bpf.h source code [include/linux/bpf.h]

1	/ SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note /
2	/ Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com*
3	*
4	* This program is free software; you can redistribute it and/or
5	* modify it under the terms of version 2 of the GNU General Public
6	* License as published by the Free Software Foundation.
7	*/
8	#ifndef __LINUX_BPF_H__
9	#define __LINUX_BPF_H__
10
11	#include <linux/types.h>
12	#include <linux/bpf_common.h>
13
14	/ Extended instruction set based on top of classic BPF /
15
16	/ instruction classes /
17	#define BPF_JMP32 0x06 /* jmp mode in word width */
18	#define BPF_ALU64 0x07 /* alu mode in double word width */
19
20	/ ld/ldx fields /
21	#define BPF_DW 0x18 /* double word (64-bit) */
22	#define BPF_ATOMIC 0xc0 /* atomic memory ops - op type in immediate */
23	#define BPF_XADD 0xc0 /* exclusive add - legacy name */
24
25	/ alu/jmp fields /
26	#define BPF_MOV 0xb0 /* mov reg to reg */
27	#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
28
29	/ change endianness of a register /
30	#define BPF_END 0xd0 /* flags for endianness conversion: */
31	#define BPF_TO_LE 0x00 /* convert to little-endian */
32	#define BPF_TO_BE 0x08 /* convert to big-endian */
33	#define BPF_FROM_LE BPF_TO_LE
34	#define BPF_FROM_BE BPF_TO_BE
35
36	/ jmp encodings /
37	#define BPF_JNE 0x50 /* jump != */
38	#define BPF_JLT 0xa0 /* LT is unsigned, '<' */
39	#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
40	#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
41	#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
42	#define BPF_JSLT 0xc0 /* SLT is signed, '<' */
43	#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
44	#define BPF_CALL 0x80 /* function call */
45	#define BPF_EXIT 0x90 /* function return */
46
47	/ atomic op type fields (stored in immediate) /
48	#define BPF_FETCH 0x01 /* not an opcode on its own, used to build others */
49	#define BPF_XCHG (0xe0 \| BPF_FETCH) /* atomic exchange */
50	#define BPF_CMPXCHG (0xf0 \| BPF_FETCH) /* atomic compare-and-write */
51
52	/ Register numbers /
53	enum {
54	BPF_REG_0 = `0`,
55	BPF_REG_1,
56	BPF_REG_2,
57	BPF_REG_3,
58	BPF_REG_4,
59	BPF_REG_5,
60	BPF_REG_6,
61	BPF_REG_7,
62	BPF_REG_8,
63	BPF_REG_9,
64	BPF_REG_10,
65	__MAX_BPF_REG,
66	};
67
68	/ BPF has 10 general purpose 64-bit registers and stack frame. /
69	#define MAX_BPF_REG __MAX_BPF_REG
70
71	struct bpf_insn {
72	__u8 code; / opcode /
73	__u8 dst_reg:`4`; / dest register /
74	__u8 src_reg:`4`; / source register /
75	__s16 off; / signed offset /
76	__s32 imm; / signed immediate constant /
77	};
78
79	/ Key of an a BPF_MAP_TYPE_LPM_TRIE entry /
80	struct bpf_lpm_trie_key {
81	__u32 prefixlen; / up to 32 for AF_INET, 128 for AF_INET6 /
82	__u8 data[`0`]; / Arbitrary size /
83	};
84
85	struct bpf_cgroup_storage_key {
86	__u64 cgroup_inode_id; / cgroup inode id /
87	__u32 attach_type; / program attach type (enum bpf_attach_type) /
88	};
89
90	union bpf_iter_link_info {
91	struct {
92	__u32 map_fd;
93	} map;
94	};
95
96	/ BPF syscall commands, see bpf(2) man-page for more details. /
97	/**
98	* DOC: eBPF Syscall Preamble
99	*
100	* The operation to be performed by the bpf\ () system call is determined
101	* by the cmd argument. Each operation takes an accompanying argument,
102	* provided via attr, which is a pointer to a union of type bpf_attr (see
103	* below). The size argument is the size of the union pointed to by attr.
104	*/
105	/**
106	* DOC: eBPF Syscall Commands
107	*
108	* BPF_MAP_CREATE
109	* Description
110	* Create a map and return a file descriptor that refers to the
111	* map. The close-on-exec file descriptor flag (see fcntl\ (2))
112	* is automatically enabled for the new file descriptor.
113	*
114	* Applying close\ (2) to the file descriptor returned by
115	* BPF_MAP_CREATE will delete the map (but see NOTES).
116	*
117	* Return
118	* A new file descriptor (a nonnegative integer), or -1 if an
119	* error occurred (in which case, errno is set appropriately).
120	*
121	* BPF_MAP_LOOKUP_ELEM
122	* Description
123	* Look up an element with a given key in the map referred to
124	* by the file descriptor map_fd.
125	*
126	* The flags argument may be specified as one of the
127	* following:
128	*
129	* BPF_F_LOCK
130	* Look up the value of a spin-locked map without
131	* returning the lock. This must be specified if the
132	* elements contain a spinlock.
133	*
134	* Return
135	* Returns zero on success. On error, -1 is returned and errno
136	* is set appropriately.
137	*
138	* BPF_MAP_UPDATE_ELEM
139	* Description
140	* Create or update an element (key/value pair) in a specified map.
141	*
142	* The flags argument should be specified as one of the
143	* following:
144	*
145	* BPF_ANY
146	* Create a new element or update an existing element.
147	* BPF_NOEXIST
148	* Create a new element only if it did not exist.
149	* BPF_EXIST
150	* Update an existing element.
151	* BPF_F_LOCK
152	* Update a spin_lock-ed map element.
153	*
154	* Return
155	* Returns zero on success. On error, -1 is returned and errno
156	* is set appropriately.
157	*
158	* May set errno to EINVAL, EPERM, ENOMEM,
159	* E2BIG, EEXIST, or ENOENT.
160	*
161	* E2BIG
162	* The number of elements in the map reached the
163	* max_entries limit specified at map creation time.
164	* EEXIST
165	* If flags specifies BPF_NOEXIST and the element
166	* with key already exists in the map.
167	* ENOENT
168	* If flags specifies BPF_EXIST and the element with
169	* key does not exist in the map.
170	*
171	* BPF_MAP_DELETE_ELEM
172	* Description
173	* Look up and delete an element by key in a specified map.
174	*
175	* Return
176	* Returns zero on success. On error, -1 is returned and errno
177	* is set appropriately.
178	*
179	* BPF_MAP_GET_NEXT_KEY
180	* Description
181	* Look up an element by key in a specified map and return the key
182	* of the next element. Can be used to iterate over all elements
183	* in the map.
184	*
185	* Return
186	* Returns zero on success. On error, -1 is returned and errno
187	* is set appropriately.
188	*
189	* The following cases can be used to iterate over all elements of
190	* the map:
191	*
192	* * If key is not found, the operation returns zero and sets
193	* the next_key pointer to the key of the first element.
194	* * If key is found, the operation returns zero and sets the
195	* next_key pointer to the key of the next element.
196	* * If key is the last element, returns -1 and errno is set
197	* to ENOENT.
198	*
199	* May set errno to ENOMEM, EFAULT, EPERM, or
200	* EINVAL on error.
201	*
202	* BPF_PROG_LOAD
203	* Description
204	* Verify and load an eBPF program, returning a new file
205	* descriptor associated with the program.
206	*
207	* Applying close\ (2) to the file descriptor returned by
208	* BPF_PROG_LOAD will unload the eBPF program (but see NOTES).
209	*
210	* The close-on-exec file descriptor flag (see fcntl\ (2)) is
211	* automatically enabled for the new file descriptor.
212	*
213	* Return
214	* A new file descriptor (a nonnegative integer), or -1 if an
215	* error occurred (in which case, errno is set appropriately).
216	*
217	* BPF_OBJ_PIN
218	* Description
219	* Pin an eBPF program or map referred by the specified bpf_fd
220	* to the provided pathname on the filesystem.
221	*
222	* The pathname argument must not contain a dot (".").
223	*
224	* On success, pathname retains a reference to the eBPF object,
225	* preventing deallocation of the object when the original
226	* bpf_fd is closed. This allow the eBPF object to live beyond
227	* close\ (\ bpf_fd\ ), and hence the lifetime of the parent
228	* process.
229	*
230	* Applying unlink\ (2) or similar calls to the pathname
231	* unpins the object from the filesystem, removing the reference.
232	* If no other file descriptors or filesystem nodes refer to the
233	* same object, it will be deallocated (see NOTES).
234	*
235	* The filesystem type for the parent directory of pathname must
236	* be BPF_FS_MAGIC.
237	*
238	* Return
239	* Returns zero on success. On error, -1 is returned and errno
240	* is set appropriately.
241	*
242	* BPF_OBJ_GET
243	* Description
244	* Open a file descriptor for the eBPF object pinned to the
245	* specified pathname.
246	*
247	* Return
248	* A new file descriptor (a nonnegative integer), or -1 if an
249	* error occurred (in which case, errno is set appropriately).
250	*
251	* BPF_PROG_ATTACH
252	* Description
253	* Attach an eBPF program to a target_fd at the specified
254	* attach_type hook.
255	*
256	* The attach_type specifies the eBPF attachment point to
257	* attach the program to, and must be one of bpf_attach_type
258	* (see below).
259	*
260	* The attach_bpf_fd must be a valid file descriptor for a
261	* loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
262	* or sock_ops type corresponding to the specified attach_type.
263	*
264	* The target_fd must be a valid file descriptor for a kernel
265	* object which depends on the attach type of attach_bpf_fd:
266	*
267	* BPF_PROG_TYPE_CGROUP_DEVICE,
268	* BPF_PROG_TYPE_CGROUP_SKB,
269	* BPF_PROG_TYPE_CGROUP_SOCK,
270	* BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
271	* BPF_PROG_TYPE_CGROUP_SOCKOPT,
272	* BPF_PROG_TYPE_CGROUP_SYSCTL,
273	* BPF_PROG_TYPE_SOCK_OPS
274	*
275	* Control Group v2 hierarchy with the eBPF controller
276	* enabled. Requires the kernel to be compiled with
277	* CONFIG_CGROUP_BPF.
278	*
279	* BPF_PROG_TYPE_FLOW_DISSECTOR
280	*
281	* Network namespace (eg /proc/self/ns/net).
282	*
283	* BPF_PROG_TYPE_LIRC_MODE2
284	*
285	* LIRC device path (eg /dev/lircN). Requires the kernel
286	* to be compiled with CONFIG_BPF_LIRC_MODE2.
287	*
288	* BPF_PROG_TYPE_SK_SKB,
289	* BPF_PROG_TYPE_SK_MSG
290	*
291	* eBPF map of socket type (eg BPF_MAP_TYPE_SOCKHASH).
292	*
293	* Return
294	* Returns zero on success. On error, -1 is returned and errno
295	* is set appropriately.
296	*
297	* BPF_PROG_DETACH
298	* Description
299	* Detach the eBPF program associated with the target_fd at the
300	* hook specified by attach_type. The program must have been
301	* previously attached using BPF_PROG_ATTACH.
302	*
303	* Return
304	* Returns zero on success. On error, -1 is returned and errno
305	* is set appropriately.
306	*
307	* BPF_PROG_TEST_RUN
308	* Description
309	* Run the eBPF program associated with the prog_fd a repeat
310	* number of times against a provided program context ctx_in and
311	* data data_in, and return the modified program context
312	* ctx_out, data_out (for example, packet data), result of the
313	* execution retval, and duration of the test run.
314	*
315	* The sizes of the buffers provided as input and output
316	* parameters ctx_in, ctx_out, data_in, and data_out must
317	* be provided in the corresponding variables ctx_size_in,
318	* ctx_size_out, data_size_in, and/or data_size_out. If any
319	* of these parameters are not provided (ie set to NULL), the
320	* corresponding size field must be zero.
321	*
322	* Some program types have particular requirements:
323	*
324	* BPF_PROG_TYPE_SK_LOOKUP
325	* data_in and data_out must be NULL.
326	*
327	* BPF_PROG_TYPE_RAW_TRACEPOINT,
328	* BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE
329	*
330	* ctx_out, data_in and data_out must be NULL.
331	* repeat must be zero.
332	*
333	* Return
334	* Returns zero on success. On error, -1 is returned and errno
335	* is set appropriately.
336	*
337	* ENOSPC
338	* Either data_size_out or ctx_size_out is too small.
339	* ENOTSUPP
340	* This command is not supported by the program type of
341	* the program referred to by prog_fd.
342	*
343	* BPF_PROG_GET_NEXT_ID
344	* Description
345	* Fetch the next eBPF program currently loaded into the kernel.
346	*
347	* Looks for the eBPF program with an id greater than start_id
348	* and updates next_id on success. If no other eBPF programs
349	* remain with ids higher than start_id, returns -1 and sets
350	* errno to ENOENT.
351	*
352	* Return
353	* Returns zero on success. On error, or when no id remains, -1
354	* is returned and errno is set appropriately.
355	*
356	* BPF_MAP_GET_NEXT_ID
357	* Description
358	* Fetch the next eBPF map currently loaded into the kernel.
359	*
360	* Looks for the eBPF map with an id greater than start_id
361	* and updates next_id on success. If no other eBPF maps
362	* remain with ids higher than start_id, returns -1 and sets
363	* errno to ENOENT.
364	*
365	* Return
366	* Returns zero on success. On error, or when no id remains, -1
367	* is returned and errno is set appropriately.
368	*
369	* BPF_PROG_GET_FD_BY_ID
370	* Description
371	* Open a file descriptor for the eBPF program corresponding to
372	* prog_id.
373	*
374	* Return
375	* A new file descriptor (a nonnegative integer), or -1 if an
376	* error occurred (in which case, errno is set appropriately).
377	*
378	* BPF_MAP_GET_FD_BY_ID
379	* Description
380	* Open a file descriptor for the eBPF map corresponding to
381	* map_id.
382	*
383	* Return
384	* A new file descriptor (a nonnegative integer), or -1 if an
385	* error occurred (in which case, errno is set appropriately).
386	*
387	* BPF_OBJ_GET_INFO_BY_FD
388	* Description
389	* Obtain information about the eBPF object corresponding to
390	* bpf_fd.
391	*
392	* Populates up to info_len bytes of info, which will be in
393	* one of the following formats depending on the eBPF object type
394	* of bpf_fd:
395	*
396	* * struct bpf_prog_info
397	* * struct bpf_map_info
398	* * struct bpf_btf_info
399	* * struct bpf_link_info
400	*
401	* Return
402	* Returns zero on success. On error, -1 is returned and errno
403	* is set appropriately.
404	*
405	* BPF_PROG_QUERY
406	* Description
407	* Obtain information about eBPF programs associated with the
408	* specified attach_type hook.
409	*
410	* The target_fd must be a valid file descriptor for a kernel
411	* object which depends on the attach type of attach_bpf_fd:
412	*
413	* BPF_PROG_TYPE_CGROUP_DEVICE,
414	* BPF_PROG_TYPE_CGROUP_SKB,
415	* BPF_PROG_TYPE_CGROUP_SOCK,
416	* BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
417	* BPF_PROG_TYPE_CGROUP_SOCKOPT,
418	* BPF_PROG_TYPE_CGROUP_SYSCTL,
419	* BPF_PROG_TYPE_SOCK_OPS
420	*
421	* Control Group v2 hierarchy with the eBPF controller
422	* enabled. Requires the kernel to be compiled with
423	* CONFIG_CGROUP_BPF.
424	*
425	* BPF_PROG_TYPE_FLOW_DISSECTOR
426	*
427	* Network namespace (eg /proc/self/ns/net).
428	*
429	* BPF_PROG_TYPE_LIRC_MODE2
430	*
431	* LIRC device path (eg /dev/lircN). Requires the kernel
432	* to be compiled with CONFIG_BPF_LIRC_MODE2.
433	*
434	* BPF_PROG_QUERY always fetches the number of programs
435	* attached and the attach_flags which were used to attach those
436	* programs. Additionally, if prog_ids is nonzero and the number
437	* of attached programs is less than prog_cnt, populates
438	* prog_ids with the eBPF program ids of the programs attached
439	* at target_fd.
440	*
441	* The following flags may alter the result:
442	*
443	* BPF_F_QUERY_EFFECTIVE
444	* Only return information regarding programs which are
445	* currently effective at the specified target_fd.
446	*
447	* Return
448	* Returns zero on success. On error, -1 is returned and errno
449	* is set appropriately.
450	*
451	* BPF_RAW_TRACEPOINT_OPEN
452	* Description
453	* Attach an eBPF program to a tracepoint name to access kernel
454	* internal arguments of the tracepoint in their raw form.
455	*
456	* The prog_fd must be a valid file descriptor associated with
457	* a loaded eBPF program of type BPF_PROG_TYPE_RAW_TRACEPOINT.
458	*
459	* No ABI guarantees are made about the content of tracepoint
460	* arguments exposed to the corresponding eBPF program.
461	*
462	* Applying close\ (2) to the file descriptor returned by
463	* BPF_RAW_TRACEPOINT_OPEN will delete the map (but see NOTES).
464	*
465	* Return
466	* A new file descriptor (a nonnegative integer), or -1 if an
467	* error occurred (in which case, errno is set appropriately).
468	*
469	* BPF_BTF_LOAD
470	* Description
471	* Verify and load BPF Type Format (BTF) metadata into the kernel,
472	* returning a new file descriptor associated with the metadata.
473	* BTF is described in more detail at
474	* https://www.kernel.org/doc/html/latest/bpf/btf.html.
475	*
476	* The btf parameter must point to valid memory providing
477	* btf_size bytes of BTF binary metadata.
478	*
479	* The returned file descriptor can be passed to other bpf\ ()
480	* subcommands such as BPF_PROG_LOAD or BPF_MAP_CREATE to
481	* associate the BTF with those objects.
482	*
483	* Similar to BPF_PROG_LOAD, BPF_BTF_LOAD has optional
484	* parameters to specify a btf_log_buf, btf_log_size and
485	* btf_log_level which allow the kernel to return freeform log
486	* output regarding the BTF verification process.
487	*
488	* Return
489	* A new file descriptor (a nonnegative integer), or -1 if an
490	* error occurred (in which case, errno is set appropriately).
491	*
492	* BPF_BTF_GET_FD_BY_ID
493	* Description
494	* Open a file descriptor for the BPF Type Format (BTF)
495	* corresponding to btf_id.
496	*
497	* Return
498	* A new file descriptor (a nonnegative integer), or -1 if an
499	* error occurred (in which case, errno is set appropriately).
500	*
501	* BPF_TASK_FD_QUERY
502	* Description
503	* Obtain information about eBPF programs associated with the
504	* target process identified by pid and fd.
505	*
506	* If the pid and fd are associated with a tracepoint, kprobe
507	* or uprobe perf event, then the prog_id and fd_type will
508	* be populated with the eBPF program id and file descriptor type
509	* of type bpf_task_fd_type. If associated with a kprobe or
510	* uprobe, the probe_offset and probe_addr will also be
511	* populated. Optionally, if buf is provided, then up to
512	* buf_len bytes of buf will be populated with the name of
513	* the tracepoint, kprobe or uprobe.
514	*
515	* The resulting prog_id may be introspected in deeper detail
516	* using BPF_PROG_GET_FD_BY_ID and BPF_OBJ_GET_INFO_BY_FD.
517	*
518	* Return
519	* Returns zero on success. On error, -1 is returned and errno
520	* is set appropriately.
521	*
522	* BPF_MAP_LOOKUP_AND_DELETE_ELEM
523	* Description
524	* Look up an element with the given key in the map referred to
525	* by the file descriptor fd, and if found, delete the element.
526	*
527	* For BPF_MAP_TYPE_QUEUE and BPF_MAP_TYPE_STACK map
528	* types, the flags argument needs to be set to 0, but for other
529	* map types, it may be specified as:
530	*
531	* BPF_F_LOCK
532	* Look up and delete the value of a spin-locked map
533	* without returning the lock. This must be specified if
534	* the elements contain a spinlock.
535	*
536	* The BPF_MAP_TYPE_QUEUE and BPF_MAP_TYPE_STACK map types
537	* implement this command as a "pop" operation, deleting the top
538	* element rather than one corresponding to key.
539	* The key and key_len parameters should be zeroed when
540	* issuing this operation for these map types.
541	*
542	* This command is only valid for the following map types:
543	* * BPF_MAP_TYPE_QUEUE
544	* * BPF_MAP_TYPE_STACK
545	* * BPF_MAP_TYPE_HASH
546	* * BPF_MAP_TYPE_PERCPU_HASH
547	* * BPF_MAP_TYPE_LRU_HASH
548	* * BPF_MAP_TYPE_LRU_PERCPU_HASH
549	*
550	* Return
551	* Returns zero on success. On error, -1 is returned and errno
552	* is set appropriately.
553	*
554	* BPF_MAP_FREEZE
555	* Description
556	* Freeze the permissions of the specified map.
557	*
558	* Write permissions may be frozen by passing zero flags.
559	* Upon success, no future syscall invocations may alter the
560	* map state of map_fd. Write operations from eBPF programs
561	* are still possible for a frozen map.
562	*
563	* Not supported for maps of type BPF_MAP_TYPE_STRUCT_OPS.
564	*
565	* Return
566	* Returns zero on success. On error, -1 is returned and errno
567	* is set appropriately.
568	*
569	* BPF_BTF_GET_NEXT_ID
570	* Description
571	* Fetch the next BPF Type Format (BTF) object currently loaded
572	* into the kernel.
573	*
574	* Looks for the BTF object with an id greater than start_id
575	* and updates next_id on success. If no other BTF objects
576	* remain with ids higher than start_id, returns -1 and sets
577	* errno to ENOENT.
578	*
579	* Return
580	* Returns zero on success. On error, or when no id remains, -1
581	* is returned and errno is set appropriately.
582	*
583	* BPF_MAP_LOOKUP_BATCH
584	* Description
585	* Iterate and fetch multiple elements in a map.
586	*
587	* Two opaque values are used to manage batch operations,
588	* in_batch and out_batch. Initially, in_batch must be set
589	* to NULL to begin the batched operation. After each subsequent
590	* BPF_MAP_LOOKUP_BATCH, the caller should pass the resultant
591	* out_batch as the in_batch for the next operation to
592	* continue iteration from the current point.
593	*
594	* The keys and values are output parameters which must point
595	* to memory large enough to hold count items based on the key
596	* and value size of the map map_fd. The keys buffer must be
597	* of key_size * count. The values buffer must be of
598	* value_size * count.
599	*
600	* The elem_flags argument may be specified as one of the
601	* following:
602	*
603	* BPF_F_LOCK
604	* Look up the value of a spin-locked map without
605	* returning the lock. This must be specified if the
606	* elements contain a spinlock.
607	*
608	* On success, count elements from the map are copied into the
609	* user buffer, with the keys copied into keys and the values
610	* copied into the corresponding indices in values.
611	*
612	* If an error is returned and errno is not EFAULT, count
613	* is set to the number of successfully processed elements.
614	*
615	* Return
616	* Returns zero on success. On error, -1 is returned and errno
617	* is set appropriately.
618	*
619	* May set errno to ENOSPC to indicate that keys or
620	* values is too small to dump an entire bucket during
621	* iteration of a hash-based map type.
622	*
623	* BPF_MAP_LOOKUP_AND_DELETE_BATCH
624	* Description
625	* Iterate and delete all elements in a map.
626	*
627	* This operation has the same behavior as
628	* BPF_MAP_LOOKUP_BATCH with two exceptions:
629	*
630	* * Every element that is successfully returned is also deleted
631	* from the map. This is at least count elements. Note that
632	* count is both an input and an output parameter.
633	* * Upon returning with errno set to EFAULT, up to
634	* count elements may be deleted without returning the keys
635	* and values of the deleted elements.
636	*
637	* Return
638	* Returns zero on success. On error, -1 is returned and errno
639	* is set appropriately.
640	*
641	* BPF_MAP_UPDATE_BATCH
642	* Description
643	* Update multiple elements in a map by key.
644	*
645	* The keys and values are input parameters which must point
646	* to memory large enough to hold count items based on the key
647	* and value size of the map map_fd. The keys buffer must be
648	* of key_size * count. The values buffer must be of
649	* value_size * count.
650	*
651	* Each element specified in keys is sequentially updated to the
652	* value in the corresponding index in values. The in_batch
653	* and out_batch parameters are ignored and should be zeroed.
654	*
655	* The elem_flags argument should be specified as one of the
656	* following:
657	*
658	* BPF_ANY
659	* Create new elements or update a existing elements.
660	* BPF_NOEXIST
661	* Create new elements only if they do not exist.
662	* BPF_EXIST
663	* Update existing elements.
664	* BPF_F_LOCK
665	* Update spin_lock-ed map elements. This must be
666	* specified if the map value contains a spinlock.
667	*
668	* On success, count elements from the map are updated.
669	*
670	* If an error is returned and errno is not EFAULT, count
671	* is set to the number of successfully processed elements.
672	*
673	* Return
674	* Returns zero on success. On error, -1 is returned and errno
675	* is set appropriately.
676	*
677	* May set errno to EINVAL, EPERM, ENOMEM, or
678	* E2BIG. E2BIG indicates that the number of elements in
679	* the map reached the max_entries limit specified at map
680	* creation time.
681	*
682	* May set errno to one of the following error codes under
683	* specific circumstances:
684	*
685	* EEXIST
686	* If flags specifies BPF_NOEXIST and the element
687	* with key already exists in the map.
688	* ENOENT
689	* If flags specifies BPF_EXIST and the element with
690	* key does not exist in the map.
691	*
692	* BPF_MAP_DELETE_BATCH
693	* Description
694	* Delete multiple elements in a map by key.
695	*
696	* The keys parameter is an input parameter which must point
697	* to memory large enough to hold count items based on the key
698	* size of the map map_fd, that is, key_size * count.
699	*
700	* Each element specified in keys is sequentially deleted. The
701	* in_batch, out_batch, and values parameters are ignored
702	* and should be zeroed.
703	*
704	* The elem_flags argument may be specified as one of the
705	* following:
706	*
707	* BPF_F_LOCK
708	* Look up the value of a spin-locked map without
709	* returning the lock. This must be specified if the
710	* elements contain a spinlock.
711	*
712	* On success, count elements from the map are updated.
713	*
714	* If an error is returned and errno is not EFAULT, count
715	* is set to the number of successfully processed elements. If
716	* errno is EFAULT, up to count elements may be been
717	* deleted.
718	*
719	* Return
720	* Returns zero on success. On error, -1 is returned and errno
721	* is set appropriately.
722	*
723	* BPF_LINK_CREATE
724	* Description
725	* Attach an eBPF program to a target_fd at the specified
726	* attach_type hook and return a file descriptor handle for
727	* managing the link.
728	*
729	* Return
730	* A new file descriptor (a nonnegative integer), or -1 if an
731	* error occurred (in which case, errno is set appropriately).
732	*
733	* BPF_LINK_UPDATE
734	* Description
735	* Update the eBPF program in the specified link_fd to
736	* new_prog_fd.
737	*
738	* Return
739	* Returns zero on success. On error, -1 is returned and errno
740	* is set appropriately.
741	*
742	* BPF_LINK_GET_FD_BY_ID
743	* Description
744	* Open a file descriptor for the eBPF Link corresponding to
745	* link_id.
746	*
747	* Return
748	* A new file descriptor (a nonnegative integer), or -1 if an
749	* error occurred (in which case, errno is set appropriately).
750	*
751	* BPF_LINK_GET_NEXT_ID
752	* Description
753	* Fetch the next eBPF link currently loaded into the kernel.
754	*
755	* Looks for the eBPF link with an id greater than start_id
756	* and updates next_id on success. If no other eBPF links
757	* remain with ids higher than start_id, returns -1 and sets
758	* errno to ENOENT.
759	*
760	* Return
761	* Returns zero on success. On error, or when no id remains, -1
762	* is returned and errno is set appropriately.
763	*
764	* BPF_ENABLE_STATS
765	* Description
766	* Enable eBPF runtime statistics gathering.
767	*
768	* Runtime statistics gathering for the eBPF runtime is disabled
769	* by default to minimize the corresponding performance overhead.
770	* This command enables statistics globally.
771	*
772	* Multiple programs may independently enable statistics.
773	* After gathering the desired statistics, eBPF runtime statistics
774	* may be disabled again by calling close\ (2) for the file
775	* descriptor returned by this function. Statistics will only be
776	* disabled system-wide when all outstanding file descriptors
777	* returned by prior calls for this subcommand are closed.
778	*
779	* Return
780	* A new file descriptor (a nonnegative integer), or -1 if an
781	* error occurred (in which case, errno is set appropriately).
782	*
783	* BPF_ITER_CREATE
784	* Description
785	* Create an iterator on top of the specified link_fd (as
786	* previously created using BPF_LINK_CREATE) and return a
787	* file descriptor that can be used to trigger the iteration.
788	*
789	* If the resulting file descriptor is pinned to the filesystem
790	* using BPF_OBJ_PIN, then subsequent read\ (2) syscalls
791	* for that path will trigger the iterator to read kernel state
792	* using the eBPF program attached to link_fd.
793	*
794	* Return
795	* A new file descriptor (a nonnegative integer), or -1 if an
796	* error occurred (in which case, errno is set appropriately).
797	*
798	* BPF_LINK_DETACH
799	* Description
800	* Forcefully detach the specified link_fd from its
801	* corresponding attachment point.
802	*
803	* Return
804	* Returns zero on success. On error, -1 is returned and errno
805	* is set appropriately.
806	*
807	* BPF_PROG_BIND_MAP
808	* Description
809	* Bind a map to the lifetime of an eBPF program.
810	*
811	* The map identified by map_fd is bound to the program
812	* identified by prog_fd and only released when prog_fd is
813	* released. This may be used in cases where metadata should be
814	* associated with a program which otherwise does not contain any
815	* references to the map (for example, embedded in the eBPF
816	* program instructions).
817	*
818	* Return
819	* Returns zero on success. On error, -1 is returned and errno
820	* is set appropriately.
821	*
822	* NOTES
823	* eBPF objects (maps and programs) can be shared between processes.
824	*
825	* * After fork\ (2), the child inherits file descriptors
826	* referring to the same eBPF objects.
827	* * File descriptors referring to eBPF objects can be transferred over
828	* unix\ (7) domain sockets.
829	* * File descriptors referring to eBPF objects can be duplicated in the
830	* usual way, using dup\ (2) and similar calls.
831	* * File descriptors referring to eBPF objects can be pinned to the
832	* filesystem using the BPF_OBJ_PIN command of bpf\ (2).
833	*
834	* An eBPF object is deallocated only after all file descriptors referring
835	* to the object have been closed and no references remain pinned to the
836	* filesystem or attached (for example, bound to a program or device).
837	*/
838	enum bpf_cmd {
839	BPF_MAP_CREATE,
840	BPF_MAP_LOOKUP_ELEM,
841	BPF_MAP_UPDATE_ELEM,
842	BPF_MAP_DELETE_ELEM,
843	BPF_MAP_GET_NEXT_KEY,
844	BPF_PROG_LOAD,
845	BPF_OBJ_PIN,
846	BPF_OBJ_GET,
847	BPF_PROG_ATTACH,
848	BPF_PROG_DETACH,
849	BPF_PROG_TEST_RUN,
850	BPF_PROG_RUN = BPF_PROG_TEST_RUN,
851	BPF_PROG_GET_NEXT_ID,
852	BPF_MAP_GET_NEXT_ID,
853	BPF_PROG_GET_FD_BY_ID,
854	BPF_MAP_GET_FD_BY_ID,
855	BPF_OBJ_GET_INFO_BY_FD,
856	BPF_PROG_QUERY,
857	BPF_RAW_TRACEPOINT_OPEN,
858	BPF_BTF_LOAD,
859	BPF_BTF_GET_FD_BY_ID,
860	BPF_TASK_FD_QUERY,
861	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
862	BPF_MAP_FREEZE,
863	BPF_BTF_GET_NEXT_ID,
864	BPF_MAP_LOOKUP_BATCH,
865	BPF_MAP_LOOKUP_AND_DELETE_BATCH,
866	BPF_MAP_UPDATE_BATCH,
867	BPF_MAP_DELETE_BATCH,
868	BPF_LINK_CREATE,
869	BPF_LINK_UPDATE,
870	BPF_LINK_GET_FD_BY_ID,
871	BPF_LINK_GET_NEXT_ID,
872	BPF_ENABLE_STATS,
873	BPF_ITER_CREATE,
874	BPF_LINK_DETACH,
875	BPF_PROG_BIND_MAP,
876	};
877
878	enum bpf_map_type {
879	BPF_MAP_TYPE_UNSPEC,
880	BPF_MAP_TYPE_HASH,
881	BPF_MAP_TYPE_ARRAY,
882	BPF_MAP_TYPE_PROG_ARRAY,
883	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
884	BPF_MAP_TYPE_PERCPU_HASH,
885	BPF_MAP_TYPE_PERCPU_ARRAY,
886	BPF_MAP_TYPE_STACK_TRACE,
887	BPF_MAP_TYPE_CGROUP_ARRAY,
888	BPF_MAP_TYPE_LRU_HASH,
889	BPF_MAP_TYPE_LRU_PERCPU_HASH,
890	BPF_MAP_TYPE_LPM_TRIE,
891	BPF_MAP_TYPE_ARRAY_OF_MAPS,
892	BPF_MAP_TYPE_HASH_OF_MAPS,
893	BPF_MAP_TYPE_DEVMAP,
894	BPF_MAP_TYPE_SOCKMAP,
895	BPF_MAP_TYPE_CPUMAP,
896	BPF_MAP_TYPE_XSKMAP,
897	BPF_MAP_TYPE_SOCKHASH,
898	BPF_MAP_TYPE_CGROUP_STORAGE,
899	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
900	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
901	BPF_MAP_TYPE_QUEUE,
902	BPF_MAP_TYPE_STACK,
903	BPF_MAP_TYPE_SK_STORAGE,
904	BPF_MAP_TYPE_DEVMAP_HASH,
905	BPF_MAP_TYPE_STRUCT_OPS,
906	BPF_MAP_TYPE_RINGBUF,
907	BPF_MAP_TYPE_INODE_STORAGE,
908	BPF_MAP_TYPE_TASK_STORAGE,
909	};
910
911	/ Note that tracing related programs such as*
912	* BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
913	* are not subject to a stable API since kernel internal data
914	* structures can change from release to release and may
915	* therefore break existing tracing BPF programs. Tracing BPF
916	* programs correspond to /a/ specific kernel which is to be
917	* analyzed, and not /a/ specific kernel /and/ all future ones.
918	*/
919	enum bpf_prog_type {
920	BPF_PROG_TYPE_UNSPEC,
921	BPF_PROG_TYPE_SOCKET_FILTER,
922	BPF_PROG_TYPE_KPROBE,
923	BPF_PROG_TYPE_SCHED_CLS,
924	BPF_PROG_TYPE_SCHED_ACT,
925	BPF_PROG_TYPE_TRACEPOINT,
926	BPF_PROG_TYPE_XDP,
927	BPF_PROG_TYPE_PERF_EVENT,
928	BPF_PROG_TYPE_CGROUP_SKB,
929	BPF_PROG_TYPE_CGROUP_SOCK,
930	BPF_PROG_TYPE_LWT_IN,
931	BPF_PROG_TYPE_LWT_OUT,
932	BPF_PROG_TYPE_LWT_XMIT,
933	BPF_PROG_TYPE_SOCK_OPS,
934	BPF_PROG_TYPE_SK_SKB,
935	BPF_PROG_TYPE_CGROUP_DEVICE,
936	BPF_PROG_TYPE_SK_MSG,
937	BPF_PROG_TYPE_RAW_TRACEPOINT,
938	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
939	BPF_PROG_TYPE_LWT_SEG6LOCAL,
940	BPF_PROG_TYPE_LIRC_MODE2,
941	BPF_PROG_TYPE_SK_REUSEPORT,
942	BPF_PROG_TYPE_FLOW_DISSECTOR,
943	BPF_PROG_TYPE_CGROUP_SYSCTL,
944	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
945	BPF_PROG_TYPE_CGROUP_SOCKOPT,
946	BPF_PROG_TYPE_TRACING,
947	BPF_PROG_TYPE_STRUCT_OPS,
948	BPF_PROG_TYPE_EXT,
949	BPF_PROG_TYPE_LSM,
950	BPF_PROG_TYPE_SK_LOOKUP,
951	BPF_PROG_TYPE_SYSCALL, / a program that can execute syscalls /
952	};
953
954	enum bpf_attach_type {
955	BPF_CGROUP_INET_INGRESS,
956	BPF_CGROUP_INET_EGRESS,
957	BPF_CGROUP_INET_SOCK_CREATE,
958	BPF_CGROUP_SOCK_OPS,
959	BPF_SK_SKB_STREAM_PARSER,
960	BPF_SK_SKB_STREAM_VERDICT,
961	BPF_CGROUP_DEVICE,
962	BPF_SK_MSG_VERDICT,
963	BPF_CGROUP_INET4_BIND,
964	BPF_CGROUP_INET6_BIND,
965	BPF_CGROUP_INET4_CONNECT,
966	BPF_CGROUP_INET6_CONNECT,
967	BPF_CGROUP_INET4_POST_BIND,
968	BPF_CGROUP_INET6_POST_BIND,
969	BPF_CGROUP_UDP4_SENDMSG,
970	BPF_CGROUP_UDP6_SENDMSG,
971	BPF_LIRC_MODE2,
972	BPF_FLOW_DISSECTOR,
973	BPF_CGROUP_SYSCTL,
974	BPF_CGROUP_UDP4_RECVMSG,
975	BPF_CGROUP_UDP6_RECVMSG,
976	BPF_CGROUP_GETSOCKOPT,
977	BPF_CGROUP_SETSOCKOPT,
978	BPF_TRACE_RAW_TP,
979	BPF_TRACE_FENTRY,
980	BPF_TRACE_FEXIT,
981	BPF_MODIFY_RETURN,
982	BPF_LSM_MAC,
983	BPF_TRACE_ITER,
984	BPF_CGROUP_INET4_GETPEERNAME,
985	BPF_CGROUP_INET6_GETPEERNAME,
986	BPF_CGROUP_INET4_GETSOCKNAME,
987	BPF_CGROUP_INET6_GETSOCKNAME,
988	BPF_XDP_DEVMAP,
989	BPF_CGROUP_INET_SOCK_RELEASE,
990	BPF_XDP_CPUMAP,
991	BPF_SK_LOOKUP,
992	BPF_XDP,
993	BPF_SK_SKB_VERDICT,
994	BPF_SK_REUSEPORT_SELECT,
995	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
996	BPF_PERF_EVENT,
997	__MAX_BPF_ATTACH_TYPE
998	};
999
1000	#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1001
1002	enum bpf_link_type {
1003	BPF_LINK_TYPE_UNSPEC = `0`,
1004	BPF_LINK_TYPE_RAW_TRACEPOINT = `1`,
1005	BPF_LINK_TYPE_TRACING = `2`,
1006	BPF_LINK_TYPE_CGROUP = `3`,
1007	BPF_LINK_TYPE_ITER = `4`,
1008	BPF_LINK_TYPE_NETNS = `5`,
1009	BPF_LINK_TYPE_XDP = `6`,
1010	BPF_LINK_TYPE_PERF_EVENT = `7`,
1011
1012	MAX_BPF_LINK_TYPE,
1013	};
1014
1015	/ cgroup-bpf attach flags used in BPF_PROG_ATTACH command*
1016	*
1017	* NONE(default): No further bpf programs allowed in the subtree.
1018	*
1019	* BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1020	* the program in this cgroup yields to sub-cgroup program.
1021	*
1022	* BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1023	* that cgroup program gets run in addition to the program in this cgroup.
1024	*
1025	* Only one program is allowed to be attached to a cgroup with
1026	* NONE or BPF_F_ALLOW_OVERRIDE flag.
1027	* Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1028	* release old program and attach the new one. Attach flags has to match.
1029	*
1030	* Multiple programs are allowed to be attached to a cgroup with
1031	* BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1032	* (those that were attached first, run first)
1033	* The programs of sub-cgroup are executed first, then programs of
1034	* this cgroup and then programs of parent cgroup.
1035	* When children program makes decision (like picking TCP CA or sock bind)
1036	* parent program has a chance to override it.
1037	*
1038	* With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1039	* programs for a cgroup. Though it's possible to replace an old program at
1040	* any position by also specifying BPF_F_REPLACE flag and position itself in
1041	* replace_bpf_fd attribute. Old program at this position will be released.
1042	*
1043	* A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1044	* A cgroup with NONE doesn't allow any programs in sub-cgroups.
1045	* Ex1:
1046	* cgrp1 (MULTI progs A, B) ->
1047	* cgrp2 (OVERRIDE prog C) ->
1048	* cgrp3 (MULTI prog D) ->
1049	* cgrp4 (OVERRIDE prog E) ->
1050	* cgrp5 (NONE prog F)
1051	* the event in cgrp5 triggers execution of F,D,A,B in that order.
1052	* if prog F is detached, the execution is E,D,A,B
1053	* if prog F and D are detached, the execution is E,A,B
1054	* if prog F, E and D are detached, the execution is C,A,B
1055	*
1056	* All eligible programs are executed regardless of return code from
1057	* earlier programs.
1058	*/
1059	#define BPF_F_ALLOW_OVERRIDE (1U << 0)
1060	#define BPF_F_ALLOW_MULTI (1U << 1)
1061	#define BPF_F_REPLACE (1U << 2)
1062
1063	/ If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the*
1064	* verifier will perform strict alignment checking as if the kernel
1065	* has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1066	* and NET_IP_ALIGN defined to 2.
1067	*/
1068	#define BPF_F_STRICT_ALIGNMENT (1U << 0)
1069
1070	/ If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the*
1071	* verifier will allow any alignment whatsoever. On platforms
1072	* with strict alignment requirements for loads ands stores (such
1073	* as sparc and mips) the verifier validates that all loads and
1074	* stores provably follow this requirement. This flag turns that
1075	* checking and enforcement off.
1076	*
1077	* It is mostly used for testing when we want to validate the
1078	* context and memory access aspects of the verifier, but because
1079	* of an unaligned access the alignment check would trigger before
1080	* the one we are interested in.
1081	*/
1082	#define BPF_F_ANY_ALIGNMENT (1U << 1)
1083
1084	/ BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.*
1085	* Verifier does sub-register def/use analysis and identifies instructions whose
1086	* def only matters for low 32-bit, high 32-bit is never referenced later
1087	* through implicit zero extension. Therefore verifier notifies JIT back-ends
1088	* that it is safe to ignore clearing high 32-bit for these instructions. This
1089	* saves some back-ends a lot of code-gen. However such optimization is not
1090	* necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1091	* hence hasn't used verifier's analysis result. But, we really want to have a
1092	* way to be able to verify the correctness of the described optimization on
1093	* x86_64 on which testsuites are frequently exercised.
1094	*
1095	* So, this flag is introduced. Once it is set, verifier will randomize high
1096	* 32-bit for those instructions who has been identified as safe to ignore them.
1097	* Then, if verifier is not doing correct analysis, such randomization will
1098	* regress tests to expose bugs.
1099	*/
1100	#define BPF_F_TEST_RND_HI32 (1U << 2)
1101
1102	/ The verifier internal test flag. Behavior is undefined /
1103	#define BPF_F_TEST_STATE_FREQ (1U << 3)
1104
1105	/ If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will*
1106	* restrict map and helper usage for such programs. Sleepable BPF programs can
1107	* only be attached to hooks where kernel execution context allows sleeping.
1108	* Such programs are allowed to use helpers that may sleep like
1109	* bpf_copy_from_user().
1110	*/
1111	#define BPF_F_SLEEPABLE (1U << 4)
1112
1113	/ When BPF ldimm64's insn[0].src_reg != 0 then this can have*
1114	* the following extensions:
1115	*
1116	* insn[0].src_reg: BPF_PSEUDO_MAP_[FD\|IDX]
1117	* insn[0].imm: map fd or fd_idx
1118	* insn[1].imm: 0
1119	* insn[0].off: 0
1120	* insn[1].off: 0
1121	* ldimm64 rewrite: address of map
1122	* verifier type: CONST_PTR_TO_MAP
1123	*/
1124	#define BPF_PSEUDO_MAP_FD 1
1125	#define BPF_PSEUDO_MAP_IDX 5
1126
1127	/ insn[0].src_reg: BPF_PSEUDO_MAP_[IDX_]VALUE*
1128	* insn[0].imm: map fd or fd_idx
1129	* insn[1].imm: offset into value
1130	* insn[0].off: 0
1131	* insn[1].off: 0
1132	* ldimm64 rewrite: address of map[0]+offset
1133	* verifier type: PTR_TO_MAP_VALUE
1134	*/
1135	#define BPF_PSEUDO_MAP_VALUE 2
1136	#define BPF_PSEUDO_MAP_IDX_VALUE 6
1137
1138	/ insn[0].src_reg: BPF_PSEUDO_BTF_ID*
1139	* insn[0].imm: kernel btd id of VAR
1140	* insn[1].imm: 0
1141	* insn[0].off: 0
1142	* insn[1].off: 0
1143	* ldimm64 rewrite: address of the kernel variable
1144	* verifier type: PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1145	* is struct/union.
1146	*/
1147	#define BPF_PSEUDO_BTF_ID 3
1148	/ insn[0].src_reg: BPF_PSEUDO_FUNC*
1149	* insn[0].imm: insn offset to the func
1150	* insn[1].imm: 0
1151	* insn[0].off: 0
1152	* insn[1].off: 0
1153	* ldimm64 rewrite: address of the function
1154	* verifier type: PTR_TO_FUNC.
1155	*/
1156	#define BPF_PSEUDO_FUNC 4
1157
1158	/ when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative*
1159	* offset to another bpf function
1160	*/
1161	#define BPF_PSEUDO_CALL 1
1162	/ when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,*
1163	* bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1164	*/
1165	#define BPF_PSEUDO_KFUNC_CALL 2
1166
1167	/ flags for BPF_MAP_UPDATE_ELEM command /
1168	enum {
1169	BPF_ANY = `0`, / create new element or update existing /
1170	BPF_NOEXIST = `1`, / create new element if it didn't exist /
1171	BPF_EXIST = `2`, / update existing element /
1172	BPF_F_LOCK = `4`, / spin_lock-ed map_lookup/map_update /
1173	};
1174
1175	/ flags for BPF_MAP_CREATE command /
1176	enum {
1177	BPF_F_NO_PREALLOC = (`1U` << `0`),
1178	/ Instead of having one common LRU list in the*
1179	* BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1180	* which can scale and perform better.
1181	* Note, the LRU nodes (including free nodes) cannot be moved
1182	* across different LRU lists.
1183	*/
1184	BPF_F_NO_COMMON_LRU = (`1U` << `1`),
1185	/ Specify numa node during map creation /
1186	BPF_F_NUMA_NODE = (`1U` << `2`),
1187
1188	/ Flags for accessing BPF object from syscall side. /
1189	BPF_F_RDONLY = (`1U` << `3`),
1190	BPF_F_WRONLY = (`1U` << `4`),
1191
1192	/ Flag for stack_map, store build_id+offset instead of pointer /
1193	BPF_F_STACK_BUILD_ID = (`1U` << `5`),
1194
1195	/ Zero-initialize hash function seed. This should only be used for testing. /
1196	BPF_F_ZERO_SEED = (`1U` << `6`),
1197
1198	/ Flags for accessing BPF object from program side. /
1199	BPF_F_RDONLY_PROG = (`1U` << `7`),
1200	BPF_F_WRONLY_PROG = (`1U` << `8`),
1201
1202	/ Clone map from listener for newly accepted socket /
1203	BPF_F_CLONE = (`1U` << `9`),
1204
1205	/ Enable memory-mapping BPF map /
1206	BPF_F_MMAPABLE = (`1U` << `10`),
1207
1208	/ Share perf_event among processes /
1209	BPF_F_PRESERVE_ELEMS = (`1U` << `11`),
1210
1211	/ Create a map that is suitable to be an inner map with dynamic max entries /
1212	BPF_F_INNER_MAP = (`1U` << `12`),
1213	};
1214
1215	/ Flags for BPF_PROG_QUERY. /
1216
1217	/ Query effective (directly attached + inherited from ancestor cgroups)*
1218	* programs that will be executed for events within a cgroup.
1219	* attach_flags with this flag are returned only for directly attached programs.
1220	*/
1221	#define BPF_F_QUERY_EFFECTIVE (1U << 0)
1222
1223	/ Flags for BPF_PROG_TEST_RUN /
1224
1225	/ If set, run the test on the cpu specified by bpf_attr.test.cpu /
1226	#define BPF_F_TEST_RUN_ON_CPU (1U << 0)
1227
1228	/ type for BPF_ENABLE_STATS /
1229	enum bpf_stats_type {
1230	/ enabled run_time_ns and run_cnt /
1231	BPF_STATS_RUN_TIME = `0`,
1232	};
1233
1234	enum bpf_stack_build_id_status {
1235	/ user space need an empty entry to identify end of a trace /
1236	BPF_STACK_BUILD_ID_EMPTY = `0`,
1237	/ with valid build_id and offset /
1238	BPF_STACK_BUILD_ID_VALID = `1`,
1239	/ couldn't get build_id, fallback to ip /
1240	BPF_STACK_BUILD_ID_IP = `2`,
1241	};
1242
1243	#define BPF_BUILD_ID_SIZE 20
1244	struct bpf_stack_build_id {
1245	__s32 status;
1246	unsigned char build_id[BPF_BUILD_ID_SIZE];
1247	union {
1248	__u64 offset;
1249	__u64 ip;
1250	};
1251	};
1252
1253	#define BPF_OBJ_NAME_LEN 16U
1254
1255	union bpf_attr {
1256	struct { / anonymous struct used by BPF_MAP_CREATE command /
1257	__u32 map_type; / one of enum bpf_map_type /
1258	__u32 key_size; / size of key in bytes /
1259	__u32 value_size; / size of value in bytes /
1260	__u32 max_entries; / max number of entries in a map /
1261	__u32 map_flags; / BPF_MAP_CREATE related*
1262	* flags defined above.
1263	*/
1264	__u32 inner_map_fd; / fd pointing to the inner map /
1265	__u32 numa_node; / numa node (effective only if*
1266	* BPF_F_NUMA_NODE is set).
1267	*/
1268	char map_name[BPF_OBJ_NAME_LEN];
1269	__u32 map_ifindex; / ifindex of netdev to create on /
1270	__u32 btf_fd; / fd pointing to a BTF type data /
1271	__u32 btf_key_type_id; / BTF type_id of the key /
1272	__u32 btf_value_type_id; / BTF type_id of the value /
1273	__u32 btf_vmlinux_value_type_id;/ BTF type_id of a kernel-*
1274	* struct stored as the
1275	* map value
1276	*/
1277	};
1278
1279	struct { / anonymous struct used by BPF_MAP__ELEM commands /*
1280	__u32 map_fd;
1281	__aligned_u64 key;
1282	union {
1283	__aligned_u64 value;
1284	__aligned_u64 next_key;
1285	};
1286	__u64 flags;
1287	};
1288
1289	struct { / struct used by BPF_MAP__BATCH commands /*
1290	__aligned_u64 in_batch; / start batch,*
1291	* NULL to start from beginning
1292	*/
1293	__aligned_u64 out_batch; / output: next start batch /
1294	__aligned_u64 keys;
1295	__aligned_u64 values;
1296	__u32 count; / input/output:*
1297	* input: # of key/value
1298	* elements
1299	* output: # of filled elements
1300	*/
1301	__u32 map_fd;
1302	__u64 elem_flags;
1303	__u64 flags;
1304	} batch;
1305
1306	struct { / anonymous struct used by BPF_PROG_LOAD command /
1307	__u32 prog_type; / one of enum bpf_prog_type /
1308	__u32 insn_cnt;
1309	__aligned_u64 insns;
1310	__aligned_u64 license;
1311	__u32 log_level; / verbosity level of verifier /
1312	__u32 log_size; / size of user buffer /
1313	__aligned_u64 log_buf; / user supplied buffer /
1314	__u32 kern_version; / not used /
1315	__u32 prog_flags;
1316	char prog_name[BPF_OBJ_NAME_LEN];
1317	__u32 prog_ifindex; / ifindex of netdev to prep for /
1318	/ For some prog types expected attach type must be known at*
1319	* load time to verify attach type specific parts of prog
1320	* (context accesses, allowed helpers, etc).
1321	*/
1322	__u32 expected_attach_type;
1323	__u32 prog_btf_fd; / fd pointing to BTF type data /
1324	__u32 func_info_rec_size; / userspace bpf_func_info size /
1325	__aligned_u64 func_info; / func info /
1326	__u32 func_info_cnt; / number of bpf_func_info records /
1327	__u32 line_info_rec_size; / userspace bpf_line_info size /
1328	__aligned_u64 line_info; / line info /
1329	__u32 line_info_cnt; / number of bpf_line_info records /
1330	__u32 attach_btf_id; / in-kernel BTF type id to attach to /
1331	union {
1332	/ valid prog_fd to attach to bpf prog /
1333	__u32 attach_prog_fd;
1334	/ or valid module BTF object fd or 0 to attach to vmlinux /
1335	__u32 attach_btf_obj_fd;
1336	};
1337	__u32 :`32`; / pad /
1338	__aligned_u64 fd_array; / array of FDs /
1339	};
1340
1341	struct { / anonymous struct used by BPF_OBJ_* commands /
1342	__aligned_u64 pathname;
1343	__u32 bpf_fd;
1344	__u32 file_flags;
1345	};
1346
1347	struct { / anonymous struct used by BPF_PROG_ATTACH/DETACH commands /
1348	__u32 target_fd; / container object to attach to /
1349	__u32 attach_bpf_fd; / eBPF program to attach /
1350	__u32 attach_type;
1351	__u32 attach_flags;
1352	__u32 replace_bpf_fd; / previously attached eBPF*
1353	* program to replace if
1354	* BPF_F_REPLACE is used
1355	*/
1356	};
1357
1358	struct { / anonymous struct used by BPF_PROG_TEST_RUN command /
1359	__u32 prog_fd;
1360	__u32 retval;
1361	__u32 data_size_in; / input: len of data_in /
1362	__u32 data_size_out; / input/output: len of data_out*
1363	* returns ENOSPC if data_out
1364	* is too small.
1365	*/
1366	__aligned_u64 data_in;
1367	__aligned_u64 data_out;
1368	__u32 repeat;
1369	__u32 duration;
1370	__u32 ctx_size_in; / input: len of ctx_in /
1371	__u32 ctx_size_out; / input/output: len of ctx_out*
1372	* returns ENOSPC if ctx_out
1373	* is too small.
1374	*/
1375	__aligned_u64 ctx_in;
1376	__aligned_u64 ctx_out;
1377	__u32 flags;
1378	__u32 cpu;
1379	} test;
1380
1381	struct { / anonymous struct used by BPF__GET__ID /
1382	union {
1383	__u32 start_id;
1384	__u32 prog_id;
1385	__u32 map_id;
1386	__u32 btf_id;
1387	__u32 link_id;
1388	};
1389	__u32 next_id;
1390	__u32 open_flags;
1391	};
1392
1393	struct { / anonymous struct used by BPF_OBJ_GET_INFO_BY_FD /
1394	__u32 bpf_fd;
1395	__u32 info_len;
1396	__aligned_u64 info;
1397	} info;
1398
1399	struct { / anonymous struct used by BPF_PROG_QUERY command /
1400	__u32 target_fd; / container object to query /
1401	__u32 attach_type;
1402	__u32 query_flags;
1403	__u32 attach_flags;
1404	__aligned_u64 prog_ids;
1405	__u32 prog_cnt;
1406	} query;
1407
1408	struct { / anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command /
1409	__u64 name;
1410	__u32 prog_fd;
1411	} raw_tracepoint;
1412
1413	struct { / anonymous struct for BPF_BTF_LOAD /
1414	__aligned_u64 btf;
1415	__aligned_u64 btf_log_buf;
1416	__u32 btf_size;
1417	__u32 btf_log_size;
1418	__u32 btf_log_level;
1419	};
1420
1421	struct {
1422	__u32 pid; / input: pid /
1423	__u32 fd; / input: fd /
1424	__u32 flags; / input: flags /
1425	__u32 buf_len; / input/output: buf len /
1426	__aligned_u64 buf; / input/output:*
1427	* tp_name for tracepoint
1428	* symbol for kprobe
1429	* filename for uprobe
1430	*/
1431	__u32 prog_id; / output: prod_id /
1432	__u32 fd_type; / output: BPF_FD_TYPE_* /
1433	__u64 probe_offset; / output: probe_offset /
1434	__u64 probe_addr; / output: probe_addr /
1435	} task_fd_query;
1436
1437	struct { / struct used by BPF_LINK_CREATE command /
1438	__u32 prog_fd; / eBPF program to attach /
1439	union {
1440	__u32 target_fd; / object to attach to /
1441	__u32 target_ifindex; / target ifindex /
1442	};
1443	__u32 attach_type; / attach type /
1444	__u32 flags; / extra flags /
1445	union {
1446	__u32 target_btf_id; / btf_id of target to attach to /
1447	struct {
1448	__aligned_u64 iter_info; / extra bpf_iter_link_info /
1449	__u32 iter_info_len; / iter_info length /
1450	};
1451	struct {
1452	/ black box user-provided value passed through*
1453	* to BPF program at the execution time and
1454	* accessible through bpf_get_attach_cookie() BPF helper
1455	*/
1456	__u64 bpf_cookie;
1457	} perf_event;
1458	};
1459	} link_create;
1460
1461	struct { / struct used by BPF_LINK_UPDATE command /
1462	__u32 link_fd; / link fd /
1463	/ new program fd to update link with /
1464	__u32 new_prog_fd;
1465	__u32 flags; / extra flags /
1466	/ expected link's program fd; is specified only if*
1467	* BPF_F_REPLACE flag is set in flags */
1468	__u32 old_prog_fd;
1469	} link_update;
1470
1471	struct {
1472	__u32 link_fd;
1473	} link_detach;
1474
1475	struct { / struct used by BPF_ENABLE_STATS command /
1476	__u32 type;
1477	} enable_stats;
1478
1479	struct { / struct used by BPF_ITER_CREATE command /
1480	__u32 link_fd;
1481	__u32 flags;
1482	} iter_create;
1483
1484	struct { / struct used by BPF_PROG_BIND_MAP command /
1485	__u32 prog_fd;
1486	__u32 map_fd;
1487	__u32 flags; / extra flags /
1488	} prog_bind_map;
1489
1490	} __attribute__((aligned(`8`)));
1491
1492	/ The description below is an attempt at providing documentation to eBPF*
1493	* developers about the multiple available eBPF helper functions. It can be
1494	* parsed and used to produce a manual page. The workflow is the following,
1495	* and requires the rst2man utility:
1496	*
1497	* $ ./scripts/bpf_doc.py \
1498	* --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1499	* $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1500	* $ man /tmp/bpf-helpers.7
1501	*
1502	* Note that in order to produce this external documentation, some RST
1503	* formatting is used in the descriptions to get "bold" and "italics" in
1504	* manual pages. Also note that the few trailing white spaces are
1505	* intentional, removing them would break paragraphs for rst2man.
1506	*
1507	* Start of BPF helper function descriptions:
1508	*
1509	* void bpf_map_lookup_elem(struct bpf_map map, const void *key)
1510	* Description
1511	* Perform a lookup in map for an entry associated to key.
1512	* Return
1513	* Map value associated to key, or NULL if no entry was
1514	* found.
1515	*
1516	* long bpf_map_update_elem(struct bpf_map map, const void key, const void *value, u64 flags)
1517	* Description
1518	* Add or update the value of the entry associated to key in
1519	* map with value. flags is one of:
1520	*
1521	* BPF_NOEXIST
1522	* The entry for key must not exist in the map.
1523	* BPF_EXIST
1524	* The entry for key must already exist in the map.
1525	* BPF_ANY
1526	* No condition on the existence of the entry for key.
1527	*
1528	* Flag value BPF_NOEXIST cannot be used for maps of types
1529	* BPF_MAP_TYPE_ARRAY or BPF_MAP_TYPE_PERCPU_ARRAY (all
1530	* elements always exist), the helper would return an error.
1531	* Return
1532	* 0 on success, or a negative error in case of failure.
1533	*
1534	* long bpf_map_delete_elem(struct bpf_map map, const void key)
1535	* Description
1536	* Delete entry with key from map.
1537	* Return
1538	* 0 on success, or a negative error in case of failure.
1539	*
1540	* long bpf_probe_read(void dst, u32 size, const void unsafe_ptr)
1541	* Description
1542	* For tracing programs, safely attempt to read size bytes from
1543	* kernel space address unsafe_ptr and store the data in dst.
1544	*
1545	* Generally, use bpf_probe_read_user\ () or
1546	* bpf_probe_read_kernel\ () instead.
1547	* Return
1548	* 0 on success, or a negative error in case of failure.
1549	*
1550	* u64 bpf_ktime_get_ns(void)
1551	* Description
1552	* Return the time elapsed since system boot, in nanoseconds.
1553	* Does not include time the system was suspended.
1554	* See: clock_gettime\ (CLOCK_MONOTONIC)
1555	* Return
1556	* Current ktime.
1557	*
1558	* long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1559	* Description
1560	* This helper is a "printk()-like" facility for debugging. It
1561	* prints a message defined by format fmt (of size fmt_size)
1562	* to file \/sys/kernel/debug/tracing/trace from DebugFS, if
1563	* available. It can take up to three additional u64
1564	* arguments (as an eBPF helpers, the total number of arguments is
1565	* limited to five).
1566	*
1567	* Each time the helper is called, it appends a line to the trace.
1568	* Lines are discarded while \/sys/kernel/debug/tracing/trace is
1569	* open, use \/sys/kernel/debug/tracing/trace_pipe to avoid this.
1570	* The format of the trace is customizable, and the exact output
1571	* one will get depends on the options set in
1572	* \/sys/kernel/debug/tracing/trace_options (see also the
1573	* README file under the same directory). However, it usually
1574	* defaults to something like:
1575	*
1576	* ::
1577	*
1578	* telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1579	*
1580	* In the above:
1581	*
1582	* * ``telnet`` is the name of the current task.
1583	* * ``470`` is the PID of the current task.
1584	* * ``001`` is the CPU number on which the task is
1585	* running.
1586	* * In ``.N..``, each character refers to a set of
1587	* options (whether irqs are enabled, scheduling
1588	* options, whether hard/softirqs are running, level of
1589	* preempt_disabled respectively). N means that
1590	* TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED
1591	* are set.
1592	* * ``419421.045894`` is a timestamp.
1593	* * ``0x00000001`` is a fake value used by BPF for the
1594	* instruction pointer register.
1595	* * ``<formatted msg>`` is the message formatted with
1596	* fmt.
1597	*
1598	* The conversion specifiers supported by fmt are similar, but
1599	* more limited than for printk(). They are %d, %i,
1600	* %u, %x, %ld, %li, %lu, %lx, %lld,
1601	* %lli, %llu, %llx, %p, %s. No modifier (size
1602	* of field, padding with zeroes, etc.) is available, and the
1603	* helper will return -EINVAL (but print nothing) if it
1604	* encounters an unknown specifier.
1605	*
1606	* Also, note that bpf_trace_printk\ () is slow, and should
1607	* only be used for debugging purposes. For this reason, a notice
1608	* block (spanning several lines) is printed to kernel logs and
1609	* states that the helper should not be used "for production use"
1610	* the first time this helper is used (or more precisely, when
1611	* trace_printk\ () buffers are allocated). For passing values
1612	* to user space, perf events should be preferred.
1613	* Return
1614	* The number of bytes written to the buffer, or a negative error
1615	* in case of failure.
1616	*
1617	* u32 bpf_get_prandom_u32(void)
1618	* Description
1619	* Get a pseudo-random number.
1620	*
1621	* From a security point of view, this helper uses its own
1622	* pseudo-random internal state, and cannot be used to infer the
1623	* seed of other random functions in the kernel. However, it is
1624	* essential to note that the generator used by the helper is not
1625	* cryptographically secure.
1626	* Return
1627	* A random 32-bit unsigned value.
1628	*
1629	* u32 bpf_get_smp_processor_id(void)
1630	* Description
1631	* Get the SMP (symmetric multiprocessing) processor id. Note that
1632	* all programs run with preemption disabled, which means that the
1633	* SMP processor id is stable during all the execution of the
1634	* program.
1635	* Return
1636	* The SMP id of the processor running the program.
1637	*
1638	* long bpf_skb_store_bytes(struct sk_buff skb, u32 offset, const void from, u32 len, u64 flags)
1639	* Description
1640	* Store len bytes from address from into the packet
1641	* associated to skb, at offset. flags are a combination of
1642	* BPF_F_RECOMPUTE_CSUM (automatically recompute the
1643	* checksum for the packet after storing the bytes) and
1644	* BPF_F_INVALIDATE_HASH (set skb\ ->hash, skb\
1645	* ->swhash and skb\ ->l4hash to 0).
1646	*
1647	* A call to this helper is susceptible to change the underlying
1648	* packet buffer. Therefore, at load time, all checks on pointers
1649	* previously done by the verifier are invalidated and must be
1650	* performed again, if the helper is used in combination with
1651	* direct packet access.
1652	* Return
1653	* 0 on success, or a negative error in case of failure.
1654	*
1655	* long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1656	* Description
1657	* Recompute the layer 3 (e.g. IP) checksum for the packet
1658	* associated to skb. Computation is incremental, so the helper
1659	* must know the former value of the header field that was
1660	* modified (from), the new value of this field (to), and the
1661	* number of bytes (2 or 4) for this field, stored in size.
1662	* Alternatively, it is possible to store the difference between
1663	* the previous and the new values of the header field in to, by
1664	* setting from and size to 0. For both methods, offset
1665	* indicates the location of the IP checksum within the packet.
1666	*
1667	* This helper works in combination with bpf_csum_diff\ (),
1668	* which does not update the checksum in-place, but offers more
1669	* flexibility and can handle sizes larger than 2 or 4 for the
1670	* checksum to update.
1671	*
1672	* A call to this helper is susceptible to change the underlying
1673	* packet buffer. Therefore, at load time, all checks on pointers
1674	* previously done by the verifier are invalidated and must be
1675	* performed again, if the helper is used in combination with
1676	* direct packet access.
1677	* Return
1678	* 0 on success, or a negative error in case of failure.
1679	*
1680	* long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1681	* Description
1682	* Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1683	* packet associated to skb. Computation is incremental, so the
1684	* helper must know the former value of the header field that was
1685	* modified (from), the new value of this field (to), and the
1686	* number of bytes (2 or 4) for this field, stored on the lowest
1687	* four bits of flags. Alternatively, it is possible to store
1688	* the difference between the previous and the new values of the
1689	* header field in to, by setting from and the four lowest
1690	* bits of flags to 0. For both methods, offset indicates the
1691	* location of the IP checksum within the packet. In addition to
1692	* the size of the field, flags can be added (bitwise OR) actual
1693	* flags. With BPF_F_MARK_MANGLED_0, a null checksum is left
1694	* untouched (unless BPF_F_MARK_ENFORCE is added as well), and
1695	* for updates resulting in a null checksum the value is set to
1696	* CSUM_MANGLED_0 instead. Flag BPF_F_PSEUDO_HDR indicates
1697	* the checksum is to be computed against a pseudo-header.
1698	*
1699	* This helper works in combination with bpf_csum_diff\ (),
1700	* which does not update the checksum in-place, but offers more
1701	* flexibility and can handle sizes larger than 2 or 4 for the
1702	* checksum to update.
1703	*
1704	* A call to this helper is susceptible to change the underlying
1705	* packet buffer. Therefore, at load time, all checks on pointers
1706	* previously done by the verifier are invalidated and must be
1707	* performed again, if the helper is used in combination with
1708	* direct packet access.
1709	* Return
1710	* 0 on success, or a negative error in case of failure.
1711	*
1712	* long bpf_tail_call(void ctx, struct bpf_map prog_array_map, u32 index)
1713	* Description
1714	* This special helper is used to trigger a "tail call", or in
1715	* other words, to jump into another eBPF program. The same stack
1716	* frame is used (but values on stack and in registers for the
1717	* caller are not accessible to the callee). This mechanism allows
1718	* for program chaining, either for raising the maximum number of
1719	* available eBPF instructions, or to execute given programs in
1720	* conditional blocks. For security reasons, there is an upper
1721	* limit to the number of successive tail calls that can be
1722	* performed.
1723	*
1724	* Upon call of this helper, the program attempts to jump into a
1725	* program referenced at index index in prog_array_map, a
1726	* special map of type BPF_MAP_TYPE_PROG_ARRAY, and passes
1727	* ctx, a pointer to the context.
1728	*
1729	* If the call succeeds, the kernel immediately runs the first
1730	* instruction of the new program. This is not a function call,
1731	* and it never returns to the previous program. If the call
1732	* fails, then the helper has no effect, and the caller continues
1733	* to run its subsequent instructions. A call can fail if the
1734	* destination program for the jump does not exist (i.e. index
1735	* is superior to the number of entries in prog_array_map), or
1736	* if the maximum number of tail calls has been reached for this
1737	* chain of programs. This limit is defined in the kernel by the
1738	* macro MAX_TAIL_CALL_CNT (not accessible to user space),
1739	* which is currently set to 32.
1740	* Return
1741	* 0 on success, or a negative error in case of failure.
1742	*
1743	* long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1744	* Description
1745	* Clone and redirect the packet associated to skb to another
1746	* net device of index ifindex. Both ingress and egress
1747	* interfaces can be used for redirection. The BPF_F_INGRESS
1748	* value in flags is used to make the distinction (ingress path
1749	* is selected if the flag is present, egress path otherwise).
1750	* This is the only flag supported for now.
1751	*
1752	* In comparison with bpf_redirect\ () helper,
1753	* bpf_clone_redirect\ () has the associated cost of
1754	* duplicating the packet buffer, but this can be executed out of
1755	* the eBPF program. Conversely, bpf_redirect\ () is more
1756	* efficient, but it is handled through an action code where the
1757	* redirection happens only after the eBPF program has returned.
1758	*
1759	* A call to this helper is susceptible to change the underlying
1760	* packet buffer. Therefore, at load time, all checks on pointers
1761	* previously done by the verifier are invalidated and must be
1762	* performed again, if the helper is used in combination with
1763	* direct packet access.
1764	* Return
1765	* 0 on success, or a negative error in case of failure. Positive
1766	* error indicates a potential drop or congestion in the target
1767	* device. The particular positive error codes are not defined.
1768	*
1769	* u64 bpf_get_current_pid_tgid(void)
1770	* Return
1771	* A 64-bit integer containing the current tgid and pid, and
1772	* created as such:
1773	* current_task\ ->tgid << 32 \\|
1774	* current_task\ ->pid.
1775	*
1776	* u64 bpf_get_current_uid_gid(void)
1777	* Return
1778	* A 64-bit integer containing the current GID and UID, and
1779	* created as such: current_gid << 32 \\| current_uid.
1780	*
1781	* long bpf_get_current_comm(void *buf, u32 size_of_buf)
1782	* Description
1783	* Copy the comm attribute of the current task into buf of
1784	* size_of_buf. The comm attribute contains the name of
1785	* the executable (excluding the path) for the current task. The
1786	* size_of_buf must be strictly positive. On success, the
1787	* helper makes sure that the buf is NUL-terminated. On failure,
1788	* it is filled with zeroes.
1789	* Return
1790	* 0 on success, or a negative error in case of failure.
1791	*
1792	* u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1793	* Description
1794	* Retrieve the classid for the current task, i.e. for the net_cls
1795	* cgroup to which skb belongs.
1796	*
1797	* This helper can be used on TC egress path, but not on ingress.
1798	*
1799	* The net_cls cgroup provides an interface to tag network packets
1800	* based on a user-provided identifier for all traffic coming from
1801	* the tasks belonging to the related cgroup. See also the related
1802	* kernel documentation, available from the Linux sources in file
1803	* Documentation/admin-guide/cgroup-v1/net_cls.rst.
1804	*
1805	* The Linux kernel has two versions for cgroups: there are
1806	* cgroups v1 and cgroups v2. Both are available to users, who can
1807	* use a mixture of them, but note that the net_cls cgroup is for
1808	* cgroup v1 only. This makes it incompatible with BPF programs
1809	* run on cgroups, which is a cgroup-v2-only feature (a socket can
1810	* only hold data for one version of cgroups at a time).
1811	*
1812	* This helper is only available is the kernel was compiled with
1813	* the CONFIG_CGROUP_NET_CLASSID configuration option set to
1814	* "y" or to "m".
1815	* Return
1816	* The classid, or 0 for the default unconfigured classid.
1817	*
1818	* long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1819	* Description
1820	* Push a vlan_tci (VLAN tag control information) of protocol
1821	* vlan_proto to the packet associated to skb, then update
1822	* the checksum. Note that if vlan_proto is different from
1823	* ETH_P_8021Q and ETH_P_8021AD, it is considered to
1824	* be ETH_P_8021Q.
1825	*
1826	* A call to this helper is susceptible to change the underlying
1827	* packet buffer. Therefore, at load time, all checks on pointers
1828	* previously done by the verifier are invalidated and must be
1829	* performed again, if the helper is used in combination with
1830	* direct packet access.
1831	* Return
1832	* 0 on success, or a negative error in case of failure.
1833	*
1834	* long bpf_skb_vlan_pop(struct sk_buff *skb)
1835	* Description
1836	* Pop a VLAN header from the packet associated to skb.
1837	*
1838	* A call to this helper is susceptible to change the underlying
1839	* packet buffer. Therefore, at load time, all checks on pointers
1840	* previously done by the verifier are invalidated and must be
1841	* performed again, if the helper is used in combination with
1842	* direct packet access.
1843	* Return
1844	* 0 on success, or a negative error in case of failure.
1845	*
1846	* long bpf_skb_get_tunnel_key(struct sk_buff skb, struct bpf_tunnel_key key, u32 size, u64 flags)
1847	* Description
1848	* Get tunnel metadata. This helper takes a pointer key to an
1849	* empty struct bpf_tunnel_key of size, that will be
1850	* filled with tunnel metadata for the packet associated to skb.
1851	* The flags can be set to BPF_F_TUNINFO_IPV6, which
1852	* indicates that the tunnel is based on IPv6 protocol instead of
1853	* IPv4.
1854	*
1855	* The struct bpf_tunnel_key is an object that generalizes the
1856	* principal parameters used by various tunneling protocols into a
1857	* single struct. This way, it can be used to easily make a
1858	* decision based on the contents of the encapsulation header,
1859	* "summarized" in this struct. In particular, it holds the IP
1860	* address of the remote end (IPv4 or IPv6, depending on the case)
1861	* in key\ ->remote_ipv4 or key\ ->remote_ipv6. Also,
1862	* this struct exposes the key\ ->tunnel_id, which is
1863	* generally mapped to a VNI (Virtual Network Identifier), making
1864	* it programmable together with the bpf_skb_set_tunnel_key\
1865	* () helper.
1866	*
1867	* Let's imagine that the following code is part of a program
1868	* attached to the TC ingress interface, on one end of a GRE
1869	* tunnel, and is supposed to filter out all messages coming from
1870	* remote ends with IPv4 address other than 10.0.0.1:
1871	*
1872	* ::
1873	*
1874	* int ret;
1875	* struct bpf_tunnel_key key = {};
1876	*
1877	* ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1878	* if (ret < 0)
1879	* return TC_ACT_SHOT; // drop packet
1880	*
1881	* if (key.remote_ipv4 != 0x0a000001)
1882	* return TC_ACT_SHOT; // drop packet
1883	*
1884	* return TC_ACT_OK; // accept packet
1885	*
1886	* This interface can also be used with all encapsulation devices
1887	* that can operate in "collect metadata" mode: instead of having
1888	* one network device per specific configuration, the "collect
1889	* metadata" mode only requires a single device where the
1890	* configuration can be extracted from this helper.
1891	*
1892	* This can be used together with various tunnels such as VXLan,
1893	* Geneve, GRE or IP in IP (IPIP).
1894	* Return
1895	* 0 on success, or a negative error in case of failure.
1896	*
1897	* long bpf_skb_set_tunnel_key(struct sk_buff skb, struct bpf_tunnel_key key, u32 size, u64 flags)
1898	* Description
1899	* Populate tunnel metadata for packet associated to skb. The
1900	* tunnel metadata is set to the contents of key, of size. The
1901	* flags can be set to a combination of the following values:
1902	*
1903	* BPF_F_TUNINFO_IPV6
1904	* Indicate that the tunnel is based on IPv6 protocol
1905	* instead of IPv4.
1906	* BPF_F_ZERO_CSUM_TX
1907	* For IPv4 packets, add a flag to tunnel metadata
1908	* indicating that checksum computation should be skipped
1909	* and checksum set to zeroes.
1910	* BPF_F_DONT_FRAGMENT
1911	* Add a flag to tunnel metadata indicating that the
1912	* packet should not be fragmented.
1913	* BPF_F_SEQ_NUMBER
1914	* Add a flag to tunnel metadata indicating that a
1915	* sequence number should be added to tunnel header before
1916	* sending the packet. This flag was added for GRE
1917	* encapsulation, but might be used with other protocols
1918	* as well in the future.
1919	*
1920	* Here is a typical usage on the transmit path:
1921	*
1922	* ::
1923	*
1924	* struct bpf_tunnel_key key;
1925	* populate key ...
1926	* bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
1927	* bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
1928	*
1929	* See also the description of the bpf_skb_get_tunnel_key\ ()
1930	* helper for additional information.
1931	* Return
1932	* 0 on success, or a negative error in case of failure.
1933	*
1934	* u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
1935	* Description
1936	* Read the value of a perf event counter. This helper relies on a
1937	* map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY. The nature of
1938	* the perf event counter is selected when map is updated with
1939	* perf event file descriptors. The map is an array whose size
1940	* is the number of available CPUs, and each cell contains a value
1941	* relative to one CPU. The value to retrieve is indicated by
1942	* flags, that contains the index of the CPU to look up, masked
1943	* with BPF_F_INDEX_MASK. Alternatively, flags can be set to
1944	* BPF_F_CURRENT_CPU to indicate that the value for the
1945	* current CPU should be retrieved.
1946	*
1947	* Note that before Linux 4.13, only hardware perf event can be
1948	* retrieved.
1949	*
1950	* Also, be aware that the newer helper
1951	* bpf_perf_event_read_value\ () is recommended over
1952	* bpf_perf_event_read\ () in general. The latter has some ABI
1953	* quirks where error and counter value are used as a return code
1954	* (which is wrong to do since ranges may overlap). This issue is
1955	* fixed with bpf_perf_event_read_value\ (), which at the same
1956	* time provides more features over the bpf_perf_event_read\
1957	* () interface. Please refer to the description of
1958	* bpf_perf_event_read_value\ () for details.
1959	* Return
1960	* The value of the perf event counter read from the map, or a
1961	* negative error code in case of failure.
1962	*
1963	* long bpf_redirect(u32 ifindex, u64 flags)
1964	* Description
1965	* Redirect the packet to another net device of index ifindex.
1966	* This helper is somewhat similar to bpf_clone_redirect\
1967	* (), except that the packet is not cloned, which provides
1968	* increased performance.
1969	*
1970	* Except for XDP, both ingress and egress interfaces can be used
1971	* for redirection. The BPF_F_INGRESS value in flags is used
1972	* to make the distinction (ingress path is selected if the flag
1973	* is present, egress path otherwise). Currently, XDP only
1974	* supports redirection to the egress interface, and accepts no
1975	* flag at all.
1976	*
1977	* The same effect can also be attained with the more generic
1978	* bpf_redirect_map\ (), which uses a BPF map to store the
1979	* redirect target instead of providing it directly to the helper.
1980	* Return
1981	* For XDP, the helper returns XDP_REDIRECT on success or
1982	* XDP_ABORTED on error. For other program types, the values
1983	* are TC_ACT_REDIRECT on success or TC_ACT_SHOT on
1984	* error.
1985	*
1986	* u32 bpf_get_route_realm(struct sk_buff *skb)
1987	* Description
1988	* Retrieve the realm or the route, that is to say the
1989	* tclassid field of the destination for the skb. The
1990	* identifier retrieved is a user-provided tag, similar to the
1991	* one used with the net_cls cgroup (see description for
1992	* bpf_get_cgroup_classid\ () helper), but here this tag is
1993	* held by a route (a destination entry), not by a task.
1994	*
1995	* Retrieving this identifier works with the clsact TC egress hook
1996	* (see also tc-bpf(8)), or alternatively on conventional
1997	* classful egress qdiscs, but not on TC ingress path. In case of
1998	* clsact TC egress hook, this has the advantage that, internally,
1999	* the destination entry has not been dropped yet in the transmit
2000	* path. Therefore, the destination entry does not need to be
2001	* artificially held via netif_keep_dst\ () for a classful
2002	* qdisc until the skb is freed.
2003	*
2004	* This helper is available only if the kernel was compiled with
2005	* CONFIG_IP_ROUTE_CLASSID configuration option.
2006	* Return
2007	* The realm of the route for the packet associated to skb, or 0
2008	* if none was found.
2009	*
2010	* long bpf_perf_event_output(void ctx, struct bpf_map map, u64 flags, void *data, u64 size)
2011	* Description
2012	* Write raw data blob into a special BPF perf event held by
2013	* map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY. This perf
2014	* event must have the following attributes: PERF_SAMPLE_RAW
2015	* as sample_type, PERF_TYPE_SOFTWARE as type, and
2016	* PERF_COUNT_SW_BPF_OUTPUT as config.
2017	*
2018	* The flags are used to indicate the index in map for which
2019	* the value must be put, masked with BPF_F_INDEX_MASK.
2020	* Alternatively, flags can be set to BPF_F_CURRENT_CPU
2021	* to indicate that the index of the current CPU core should be
2022	* used.
2023	*
2024	* The value to write, of size, is passed through eBPF stack and
2025	* pointed by data.
2026	*
2027	* The context of the program ctx needs also be passed to the
2028	* helper.
2029	*
2030	* On user space, a program willing to read the values needs to
2031	* call perf_event_open\ () on the perf event (either for
2032	* one or for all CPUs) and to store the file descriptor into the
2033	* map. This must be done before the eBPF program can send data
2034	* into it. An example is available in file
2035	* samples/bpf/trace_output_user.c in the Linux kernel source
2036	* tree (the eBPF program counterpart is in
2037	* samples/bpf/trace_output_kern.c).
2038	*
2039	* bpf_perf_event_output\ () achieves better performance
2040	* than bpf_trace_printk\ () for sharing data with user
2041	* space, and is much better suitable for streaming data from eBPF
2042	* programs.
2043	*
2044	* Note that this helper is not restricted to tracing use cases
2045	* and can be used with programs attached to TC or XDP as well,
2046	* where it allows for passing data to user space listeners. Data
2047	* can be:
2048	*
2049	* * Only custom structs,
2050	* * Only the packet payload, or
2051	* * A combination of both.
2052	* Return
2053	* 0 on success, or a negative error in case of failure.
2054	*
2055	* long bpf_skb_load_bytes(const void skb, u32 offset, void to, u32 len)
2056	* Description
2057	* This helper was provided as an easy way to load data from a
2058	* packet. It can be used to load len bytes from offset from
2059	* the packet associated to skb, into the buffer pointed by
2060	* to.
2061	*
2062	* Since Linux 4.7, usage of this helper has mostly been replaced
2063	* by "direct packet access", enabling packet data to be
2064	* manipulated with skb\ ->data and skb\ ->data_end
2065	* pointing respectively to the first byte of packet data and to
2066	* the byte after the last byte of packet data. However, it
2067	* remains useful if one wishes to read large quantities of data
2068	* at once from a packet into the eBPF stack.
2069	* Return
2070	* 0 on success, or a negative error in case of failure.
2071	*
2072	* long bpf_get_stackid(void ctx, struct bpf_map map, u64 flags)
2073	* Description
2074	* Walk a user or a kernel stack and return its id. To achieve
2075	* this, the helper needs ctx, which is a pointer to the context
2076	* on which the tracing program is executed, and a pointer to a
2077	* map of type BPF_MAP_TYPE_STACK_TRACE.
2078	*
2079	* The last argument, flags, holds the number of stack frames to
2080	* skip (from 0 to 255), masked with
2081	* BPF_F_SKIP_FIELD_MASK. The next bits can be used to set
2082	* a combination of the following flags:
2083	*
2084	* BPF_F_USER_STACK
2085	* Collect a user space stack instead of a kernel stack.
2086	* BPF_F_FAST_STACK_CMP
2087	* Compare stacks by hash only.
2088	* BPF_F_REUSE_STACKID
2089	* If two different stacks hash into the same stackid,
2090	* discard the old one.
2091	*
2092	* The stack id retrieved is a 32 bit long integer handle which
2093	* can be further combined with other data (including other stack
2094	* ids) and used as a key into maps. This can be useful for
2095	* generating a variety of graphs (such as flame graphs or off-cpu
2096	* graphs).
2097	*
2098	* For walking a stack, this helper is an improvement over
2099	* bpf_probe_read\ (), which can be used with unrolled loops
2100	* but is not efficient and consumes a lot of eBPF instructions.
2101	* Instead, bpf_get_stackid\ () can collect up to
2102	* PERF_MAX_STACK_DEPTH both kernel and user frames. Note that
2103	* this limit can be controlled with the sysctl program, and
2104	* that it should be manually increased in order to profile long
2105	* user stacks (such as stacks for Java programs). To do so, use:
2106	*
2107	* ::
2108	*
2109	* # sysctl kernel.perf_event_max_stack=<new value>
2110	* Return
2111	* The positive or null stack id on success, or a negative error
2112	* in case of failure.
2113	*
2114	* s64 bpf_csum_diff(__be32 from, u32 from_size, __be32 to, u32 to_size, __wsum seed)
2115	* Description
2116	* Compute a checksum difference, from the raw buffer pointed by
2117	* from, of length from_size (that must be a multiple of 4),
2118	* towards the raw buffer pointed by to, of size to_size
2119	* (same remark). An optional seed can be added to the value
2120	* (this can be cascaded, the seed may come from a previous call
2121	* to the helper).
2122	*
2123	* This is flexible enough to be used in several ways:
2124	*
2125	* * With from_size == 0, to_size > 0 and seed set to
2126	* checksum, it can be used when pushing new data.
2127	* * With from_size > 0, to_size == 0 and seed set to
2128	* checksum, it can be used when removing data from a packet.
2129	* * With from_size > 0, to_size > 0 and seed set to 0, it
2130	* can be used to compute a diff. Note that from_size and
2131	* to_size do not need to be equal.
2132	*
2133	* This helper can be used in combination with
2134	* bpf_l3_csum_replace\ () and bpf_l4_csum_replace\ (), to
2135	* which one can feed in the difference computed with
2136	* bpf_csum_diff\ ().
2137	* Return
2138	* The checksum result, or a negative error code in case of
2139	* failure.
2140	*
2141	* long bpf_skb_get_tunnel_opt(struct sk_buff skb, void opt, u32 size)
2142	* Description
2143	* Retrieve tunnel options metadata for the packet associated to
2144	* skb, and store the raw tunnel option data to the buffer opt
2145	* of size.
2146	*
2147	* This helper can be used with encapsulation devices that can
2148	* operate in "collect metadata" mode (please refer to the related
2149	* note in the description of bpf_skb_get_tunnel_key\ () for
2150	* more details). A particular example where this can be used is
2151	* in combination with the Geneve encapsulation protocol, where it
2152	* allows for pushing (with bpf_skb_get_tunnel_opt\ () helper)
2153	* and retrieving arbitrary TLVs (Type-Length-Value headers) from
2154	* the eBPF program. This allows for full customization of these
2155	* headers.
2156	* Return
2157	* The size of the option data retrieved.
2158	*
2159	* long bpf_skb_set_tunnel_opt(struct sk_buff skb, void opt, u32 size)
2160	* Description
2161	* Set tunnel options metadata for the packet associated to skb
2162	* to the option data contained in the raw buffer opt of size.
2163	*
2164	* See also the description of the bpf_skb_get_tunnel_opt\ ()
2165	* helper for additional information.
2166	* Return
2167	* 0 on success, or a negative error in case of failure.
2168	*
2169	* long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2170	* Description
2171	* Change the protocol of the skb to proto. Currently
2172	* supported are transition from IPv4 to IPv6, and from IPv6 to
2173	* IPv4. The helper takes care of the groundwork for the
2174	* transition, including resizing the socket buffer. The eBPF
2175	* program is expected to fill the new headers, if any, via
2176	* skb_store_bytes\ () and to recompute the checksums with
2177	* bpf_l3_csum_replace\ () and bpf_l4_csum_replace\
2178	* (). The main case for this helper is to perform NAT64
2179	* operations out of an eBPF program.
2180	*
2181	* Internally, the GSO type is marked as dodgy so that headers are
2182	* checked and segments are recalculated by the GSO/GRO engine.
2183	* The size for GSO target is adapted as well.
2184	*
2185	* All values for flags are reserved for future usage, and must
2186	* be left at zero.
2187	*
2188	* A call to this helper is susceptible to change the underlying
2189	* packet buffer. Therefore, at load time, all checks on pointers
2190	* previously done by the verifier are invalidated and must be
2191	* performed again, if the helper is used in combination with
2192	* direct packet access.
2193	* Return
2194	* 0 on success, or a negative error in case of failure.
2195	*
2196	* long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2197	* Description
2198	* Change the packet type for the packet associated to skb. This
2199	* comes down to setting skb\ ->pkt_type to type, except
2200	* the eBPF program does not have a write access to skb\
2201	* ->pkt_type beside this helper. Using a helper here allows
2202	* for graceful handling of errors.
2203	*
2204	* The major use case is to change incoming skbs to
2205	* PACKET_HOST in a programmatic way instead of having to
2206	* recirculate via redirect\ (..., BPF_F_INGRESS), for
2207	* example.
2208	*
2209	* Note that type only allows certain values. At this time, they
2210	* are:
2211	*
2212	* PACKET_HOST
2213	* Packet is for us.
2214	* PACKET_BROADCAST
2215	* Send packet to all.
2216	* PACKET_MULTICAST
2217	* Send packet to group.
2218	* PACKET_OTHERHOST
2219	* Send packet to someone else.
2220	* Return
2221	* 0 on success, or a negative error in case of failure.
2222	*
2223	* long bpf_skb_under_cgroup(struct sk_buff skb, struct bpf_map map, u32 index)
2224	* Description
2225	* Check whether skb is a descendant of the cgroup2 held by
2226	* map of type BPF_MAP_TYPE_CGROUP_ARRAY, at index.
2227	* Return
2228	* The return value depends on the result of the test, and can be:
2229	*
2230	* * 0, if the skb failed the cgroup2 descendant test.
2231	* * 1, if the skb succeeded the cgroup2 descendant test.
2232	* * A negative error code, if an error occurred.
2233	*
2234	* u32 bpf_get_hash_recalc(struct sk_buff *skb)
2235	* Description
2236	* Retrieve the hash of the packet, skb\ ->hash. If it is
2237	* not set, in particular if the hash was cleared due to mangling,
2238	* recompute this hash. Later accesses to the hash can be done
2239	* directly with skb\ ->hash.
2240	*
2241	* Calling bpf_set_hash_invalid\ (), changing a packet
2242	* prototype with bpf_skb_change_proto\ (), or calling
2243	* bpf_skb_store_bytes\ () with the
2244	* BPF_F_INVALIDATE_HASH are actions susceptible to clear
2245	* the hash and to trigger a new computation for the next call to
2246	* bpf_get_hash_recalc\ ().
2247	* Return
2248	* The 32-bit hash.
2249	*
2250	* u64 bpf_get_current_task(void)
2251	* Return
2252	* A pointer to the current task struct.
2253	*
2254	* long bpf_probe_write_user(void dst, const void src, u32 len)
2255	* Description
2256	* Attempt in a safe way to write len bytes from the buffer
2257	* src to dst in memory. It only works for threads that are in
2258	* user context, and dst must be a valid user space address.
2259	*
2260	* This helper should not be used to implement any kind of
2261	* security mechanism because of TOC-TOU attacks, but rather to
2262	* debug, divert, and manipulate execution of semi-cooperative
2263	* processes.
2264	*
2265	* Keep in mind that this feature is meant for experiments, and it
2266	* has a risk of crashing the system and running programs.
2267	* Therefore, when an eBPF program using this helper is attached,
2268	* a warning including PID and process name is printed to kernel
2269	* logs.
2270	* Return
2271	* 0 on success, or a negative error in case of failure.
2272	*
2273	* long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2274	* Description
2275	* Check whether the probe is being run is the context of a given
2276	* subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2277	* map of type BPF_MAP_TYPE_CGROUP_ARRAY, at index.
2278	* Return
2279	* The return value depends on the result of the test, and can be:
2280	*
2281	* * 1, if current task belongs to the cgroup2.
2282	* * 0, if current task does not belong to the cgroup2.
2283	* * A negative error code, if an error occurred.
2284	*
2285	* long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2286	* Description
2287	* Resize (trim or grow) the packet associated to skb to the
2288	* new len. The flags are reserved for future usage, and must
2289	* be left at zero.
2290	*
2291	* The basic idea is that the helper performs the needed work to
2292	* change the size of the packet, then the eBPF program rewrites
2293	* the rest via helpers like bpf_skb_store_bytes\ (),
2294	* bpf_l3_csum_replace\ (), bpf_l3_csum_replace\ ()
2295	* and others. This helper is a slow path utility intended for
2296	* replies with control messages. And because it is targeted for
2297	* slow path, the helper itself can afford to be slow: it
2298	* implicitly linearizes, unclones and drops offloads from the
2299	* skb.
2300	*
2301	* A call to this helper is susceptible to change the underlying
2302	* packet buffer. Therefore, at load time, all checks on pointers
2303	* previously done by the verifier are invalidated and must be
2304	* performed again, if the helper is used in combination with
2305	* direct packet access.
2306	* Return
2307	* 0 on success, or a negative error in case of failure.
2308	*
2309	* long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2310	* Description
2311	* Pull in non-linear data in case the skb is non-linear and not
2312	* all of len are part of the linear section. Make len bytes
2313	* from skb readable and writable. If a zero value is passed for
2314	* len, then the whole length of the skb is pulled.
2315	*
2316	* This helper is only needed for reading and writing with direct
2317	* packet access.
2318	*
2319	* For direct packet access, testing that offsets to access
2320	* are within packet boundaries (test on skb\ ->data_end) is
2321	* susceptible to fail if offsets are invalid, or if the requested
2322	* data is in non-linear parts of the skb. On failure the
2323	* program can just bail out, or in the case of a non-linear
2324	* buffer, use a helper to make the data available. The
2325	* bpf_skb_load_bytes\ () helper is a first solution to access
2326	* the data. Another one consists in using bpf_skb_pull_data
2327	* to pull in once the non-linear parts, then retesting and
2328	* eventually access the data.
2329	*
2330	* At the same time, this also makes sure the skb is uncloned,
2331	* which is a necessary condition for direct write. As this needs
2332	* to be an invariant for the write part only, the verifier
2333	* detects writes and adds a prologue that is calling
2334	* bpf_skb_pull_data() to effectively unclone the skb from
2335	* the very beginning in case it is indeed cloned.
2336	*
2337	* A call to this helper is susceptible to change the underlying
2338	* packet buffer. Therefore, at load time, all checks on pointers
2339	* previously done by the verifier are invalidated and must be
2340	* performed again, if the helper is used in combination with
2341	* direct packet access.
2342	* Return
2343	* 0 on success, or a negative error in case of failure.
2344	*
2345	* s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2346	* Description
2347	* Add the checksum csum into skb\ ->csum in case the
2348	* driver has supplied a checksum for the entire packet into that
2349	* field. Return an error otherwise. This helper is intended to be
2350	* used in combination with bpf_csum_diff\ (), in particular
2351	* when the checksum needs to be updated after data has been
2352	* written into the packet through direct packet access.
2353	* Return
2354	* The checksum on success, or a negative error code in case of
2355	* failure.
2356	*
2357	* void bpf_set_hash_invalid(struct sk_buff *skb)
2358	* Description
2359	* Invalidate the current skb\ ->hash. It can be used after
2360	* mangling on headers through direct packet access, in order to
2361	* indicate that the hash is outdated and to trigger a
2362	* recalculation the next time the kernel tries to access this
2363	* hash or when the bpf_get_hash_recalc\ () helper is called.
2364	*
2365	* long bpf_get_numa_node_id(void)
2366	* Description
2367	* Return the id of the current NUMA node. The primary use case
2368	* for this helper is the selection of sockets for the local NUMA
2369	* node, when the program is attached to sockets using the
2370	* SO_ATTACH_REUSEPORT_EBPF option (see also socket(7)),
2371	* but the helper is also available to other eBPF program types,
2372	* similarly to bpf_get_smp_processor_id\ ().
2373	* Return
2374	* The id of current NUMA node.
2375	*
2376	* long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2377	* Description
2378	* Grows headroom of packet associated to skb and adjusts the
2379	* offset of the MAC header accordingly, adding len bytes of
2380	* space. It automatically extends and reallocates memory as
2381	* required.
2382	*
2383	* This helper can be used on a layer 3 skb to push a MAC header
2384	* for redirection into a layer 2 device.
2385	*
2386	* All values for flags are reserved for future usage, and must
2387	* be left at zero.
2388	*
2389	* A call to this helper is susceptible to change the underlying
2390	* packet buffer. Therefore, at load time, all checks on pointers
2391	* previously done by the verifier are invalidated and must be
2392	* performed again, if the helper is used in combination with
2393	* direct packet access.
2394	* Return
2395	* 0 on success, or a negative error in case of failure.
2396	*
2397	* long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2398	* Description
2399	* Adjust (move) xdp_md\ ->data by delta bytes. Note that
2400	* it is possible to use a negative value for delta. This helper
2401	* can be used to prepare the packet for pushing or popping
2402	* headers.
2403	*
2404	* A call to this helper is susceptible to change the underlying
2405	* packet buffer. Therefore, at load time, all checks on pointers
2406	* previously done by the verifier are invalidated and must be
2407	* performed again, if the helper is used in combination with
2408	* direct packet access.
2409	* Return
2410	* 0 on success, or a negative error in case of failure.
2411	*
2412	* long bpf_probe_read_str(void dst, u32 size, const void unsafe_ptr)
2413	* Description
2414	* Copy a NUL terminated string from an unsafe kernel address
2415	* unsafe_ptr to dst. See bpf_probe_read_kernel_str\ () for
2416	* more details.
2417	*
2418	* Generally, use bpf_probe_read_user_str\ () or
2419	* bpf_probe_read_kernel_str\ () instead.
2420	* Return
2421	* On success, the strictly positive length of the string,
2422	* including the trailing NUL character. On error, a negative
2423	* value.
2424	*
2425	* u64 bpf_get_socket_cookie(struct sk_buff *skb)
2426	* Description
2427	* If the struct sk_buff pointed by skb has a known socket,
2428	* retrieve the cookie (generated by the kernel) of this socket.
2429	* If no cookie has been set yet, generate a new cookie. Once
2430	* generated, the socket cookie remains stable for the life of the
2431	* socket. This helper can be useful for monitoring per socket
2432	* networking traffic statistics as it provides a global socket
2433	* identifier that can be assumed unique.
2434	* Return
2435	* A 8-byte long unique number on success, or 0 if the socket
2436	* field is missing inside skb.
2437	*
2438	* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2439	* Description
2440	* Equivalent to bpf_get_socket_cookie() helper that accepts
2441	* skb, but gets socket from struct bpf_sock_addr context.
2442	* Return
2443	* A 8-byte long unique number.
2444	*
2445	* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2446	* Description
2447	* Equivalent to bpf_get_socket_cookie\ () helper that accepts
2448	* skb, but gets socket from struct bpf_sock_ops context.
2449	* Return
2450	* A 8-byte long unique number.
2451	*
2452	* u64 bpf_get_socket_cookie(struct sock *sk)
2453	* Description
2454	* Equivalent to bpf_get_socket_cookie\ () helper that accepts
2455	* sk, but gets socket from a BTF struct sock. This helper
2456	* also works for sleepable programs.
2457	* Return
2458	* A 8-byte long unique number or 0 if sk is NULL.
2459	*
2460	* u32 bpf_get_socket_uid(struct sk_buff *skb)
2461	* Return
2462	* The owner UID of the socket associated to skb. If the socket
2463	* is NULL, or if it is not a full socket (i.e. if it is a
2464	* time-wait or a request socket instead), overflowuid value
2465	* is returned (note that overflowuid might also be the actual
2466	* UID value for the socket).
2467	*
2468	* long bpf_set_hash(struct sk_buff *skb, u32 hash)
2469	* Description
2470	* Set the full hash for skb (set the field skb\ ->hash)
2471	* to value hash.
2472	* Return
2473	* 0
2474	*
2475	* long bpf_setsockopt(void bpf_socket, int level, int optname, void optval, int optlen)
2476	* Description
2477	* Emulate a call to setsockopt() on the socket associated to
2478	* bpf_socket, which must be a full socket. The level at
2479	* which the option resides and the name optname of the option
2480	* must be specified, see setsockopt(2) for more information.
2481	* The option value of length optlen is pointed by optval.
2482	*
2483	* bpf_socket should be one of the following:
2484	*
2485	* * struct bpf_sock_ops for BPF_PROG_TYPE_SOCK_OPS.
2486	* * struct bpf_sock_addr for BPF_CGROUP_INET4_CONNECT
2487	* and BPF_CGROUP_INET6_CONNECT.
2488	*
2489	* This helper actually implements a subset of setsockopt().
2490	* It supports the following level\ s:
2491	*
2492	* * SOL_SOCKET, which supports the following optname\ s:
2493	* SO_RCVBUF, SO_SNDBUF, SO_MAX_PACING_RATE,
2494	* SO_PRIORITY, SO_RCVLOWAT, SO_MARK,
2495	* SO_BINDTODEVICE, SO_KEEPALIVE.
2496	* * IPPROTO_TCP, which supports the following optname\ s:
2497	* TCP_CONGESTION, TCP_BPF_IW,
2498	* TCP_BPF_SNDCWND_CLAMP, TCP_SAVE_SYN,
2499	* TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_KEEPCNT,
2500	* TCP_SYNCNT, TCP_USER_TIMEOUT, TCP_NOTSENT_LOWAT.
2501	* * IPPROTO_IP, which supports optname IP_TOS.
2502	* * IPPROTO_IPV6, which supports optname IPV6_TCLASS.
2503	* Return
2504	* 0 on success, or a negative error in case of failure.
2505	*
2506	* long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2507	* Description
2508	* Grow or shrink the room for data in the packet associated to
2509	* skb by len_diff, and according to the selected mode.
2510	*
2511	* By default, the helper will reset any offloaded checksum
2512	* indicator of the skb to CHECKSUM_NONE. This can be avoided
2513	* by the following flag:
2514	*
2515	* * BPF_F_ADJ_ROOM_NO_CSUM_RESET: Do not reset offloaded
2516	* checksum data of the skb to CHECKSUM_NONE.
2517	*
2518	* There are two supported modes at this time:
2519	*
2520	* * BPF_ADJ_ROOM_MAC: Adjust room at the mac layer
2521	* (room space is added or removed below the layer 2 header).
2522	*
2523	* * BPF_ADJ_ROOM_NET: Adjust room at the network layer
2524	* (room space is added or removed below the layer 3 header).
2525	*
2526	* The following flags are supported at this time:
2527	*
2528	* * BPF_F_ADJ_ROOM_FIXED_GSO: Do not adjust gso_size.
2529	* Adjusting mss in this way is not allowed for datagrams.
2530	*
2531	* * BPF_F_ADJ_ROOM_ENCAP_L3_IPV4,
2532	* BPF_F_ADJ_ROOM_ENCAP_L3_IPV6:
2533	* Any new space is reserved to hold a tunnel header.
2534	* Configure skb offsets and other fields accordingly.
2535	*
2536	* * BPF_F_ADJ_ROOM_ENCAP_L4_GRE,
2537	* BPF_F_ADJ_ROOM_ENCAP_L4_UDP:
2538	* Use with ENCAP_L3 flags to further specify the tunnel type.
2539	*
2540	* * BPF_F_ADJ_ROOM_ENCAP_L2\ (len):
2541	* Use with ENCAP_L3/L4 flags to further specify the tunnel
2542	* type; len is the length of the inner MAC header.
2543	*
2544	* * BPF_F_ADJ_ROOM_ENCAP_L2_ETH:
2545	* Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2546	* L2 type as Ethernet.
2547	*
2548	* A call to this helper is susceptible to change the underlying
2549	* packet buffer. Therefore, at load time, all checks on pointers
2550	* previously done by the verifier are invalidated and must be
2551	* performed again, if the helper is used in combination with
2552	* direct packet access.
2553	* Return
2554	* 0 on success, or a negative error in case of failure.
2555	*
2556	* long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2557	* Description
2558	* Redirect the packet to the endpoint referenced by map at
2559	* index key. Depending on its type, this map can contain
2560	* references to net devices (for forwarding packets through other
2561	* ports), or to CPUs (for redirecting XDP frames to another CPU;
2562	* but this is only implemented for native XDP (with driver
2563	* support) as of this writing).
2564	*
2565	* The lower two bits of flags are used as the return code if
2566	* the map lookup fails. This is so that the return value can be
2567	* one of the XDP program return codes up to XDP_TX, as chosen
2568	* by the caller. The higher bits of flags can be set to
2569	* BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2570	*
2571	* With BPF_F_BROADCAST the packet will be broadcasted to all the
2572	* interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2573	* interface will be excluded when do broadcasting.
2574	*
2575	* See also bpf_redirect\ (), which only supports redirecting
2576	* to an ifindex, but doesn't require a map to do so.
2577	* Return
2578	* XDP_REDIRECT on success, or the value of the two lower bits
2579	* of the flags argument on error.
2580	*
2581	* long bpf_sk_redirect_map(struct sk_buff skb, struct bpf_map map, u32 key, u64 flags)
2582	* Description
2583	* Redirect the packet to the socket referenced by map (of type
2584	* BPF_MAP_TYPE_SOCKMAP) at index key. Both ingress and
2585	* egress interfaces can be used for redirection. The
2586	* BPF_F_INGRESS value in flags is used to make the
2587	* distinction (ingress path is selected if the flag is present,
2588	* egress path otherwise). This is the only flag supported for now.
2589	* Return
2590	* SK_PASS on success, or SK_DROP on error.
2591	*
2592	* long bpf_sock_map_update(struct bpf_sock_ops skops, struct bpf_map map, void *key, u64 flags)
2593	* Description
2594	* Add an entry to, or update a map referencing sockets. The
2595	* skops is used as a new value for the entry associated to
2596	* key. flags is one of:
2597	*
2598	* BPF_NOEXIST
2599	* The entry for key must not exist in the map.
2600	* BPF_EXIST
2601	* The entry for key must already exist in the map.
2602	* BPF_ANY
2603	* No condition on the existence of the entry for key.
2604	*
2605	* If the map has eBPF programs (parser and verdict), those will
2606	* be inherited by the socket being added. If the socket is
2607	* already attached to eBPF programs, this results in an error.
2608	* Return
2609	* 0 on success, or a negative error in case of failure.
2610	*
2611	* long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2612	* Description
2613	* Adjust the address pointed by xdp_md\ ->data_meta by
2614	* delta (which can be positive or negative). Note that this
2615	* operation modifies the address stored in xdp_md\ ->data,
2616	* so the latter must be loaded only after the helper has been
2617	* called.
2618	*
2619	* The use of xdp_md\ ->data_meta is optional and programs
2620	* are not required to use it. The rationale is that when the
2621	* packet is processed with XDP (e.g. as DoS filter), it is
2622	* possible to push further meta data along with it before passing
2623	* to the stack, and to give the guarantee that an ingress eBPF
2624	* program attached as a TC classifier on the same device can pick
2625	* this up for further post-processing. Since TC works with socket
2626	* buffers, it remains possible to set from XDP the mark or
2627	* priority pointers, or other pointers for the socket buffer.
2628	* Having this scratch space generic and programmable allows for
2629	* more flexibility as the user is free to store whatever meta
2630	* data they need.
2631	*
2632	* A call to this helper is susceptible to change the underlying
2633	* packet buffer. Therefore, at load time, all checks on pointers
2634	* previously done by the verifier are invalidated and must be
2635	* performed again, if the helper is used in combination with
2636	* direct packet access.
2637	* Return
2638	* 0 on success, or a negative error in case of failure.
2639	*
2640	* long bpf_perf_event_read_value(struct bpf_map map, u64 flags, struct bpf_perf_event_value buf, u32 buf_size)
2641	* Description
2642	* Read the value of a perf event counter, and store it into buf
2643	* of size buf_size. This helper relies on a map of type
2644	* BPF_MAP_TYPE_PERF_EVENT_ARRAY. The nature of the perf event
2645	* counter is selected when map is updated with perf event file
2646	* descriptors. The map is an array whose size is the number of
2647	* available CPUs, and each cell contains a value relative to one
2648	* CPU. The value to retrieve is indicated by flags, that
2649	* contains the index of the CPU to look up, masked with
2650	* BPF_F_INDEX_MASK. Alternatively, flags can be set to
2651	* BPF_F_CURRENT_CPU to indicate that the value for the
2652	* current CPU should be retrieved.
2653	*
2654	* This helper behaves in a way close to
2655	* bpf_perf_event_read\ () helper, save that instead of
2656	* just returning the value observed, it fills the buf
2657	* structure. This allows for additional data to be retrieved: in
2658	* particular, the enabled and running times (in buf\
2659	* ->enabled and buf\ ->running, respectively) are
2660	* copied. In general, bpf_perf_event_read_value\ () is
2661	* recommended over bpf_perf_event_read\ (), which has some
2662	* ABI issues and provides fewer functionalities.
2663	*
2664	* These values are interesting, because hardware PMU (Performance
2665	* Monitoring Unit) counters are limited resources. When there are
2666	* more PMU based perf events opened than available counters,
2667	* kernel will multiplex these events so each event gets certain
2668	* percentage (but not all) of the PMU time. In case that
2669	* multiplexing happens, the number of samples or counter value
2670	* will not reflect the case compared to when no multiplexing
2671	* occurs. This makes comparison between different runs difficult.
2672	* Typically, the counter value should be normalized before
2673	* comparing to other experiments. The usual normalization is done
2674	* as follows.
2675	*
2676	* ::
2677	*
2678	* normalized_counter = counter * t_enabled / t_running
2679	*
2680	* Where t_enabled is the time enabled for event and t_running is
2681	* the time running for event since last normalization. The
2682	* enabled and running times are accumulated since the perf event
2683	* open. To achieve scaling factor between two invocations of an
2684	* eBPF program, users can use CPU id as the key (which is
2685	* typical for perf array usage model) to remember the previous
2686	* value and do the calculation inside the eBPF program.
2687	* Return
2688	* 0 on success, or a negative error in case of failure.
2689	*
2690	* long bpf_perf_prog_read_value(struct bpf_perf_event_data ctx, struct bpf_perf_event_value buf, u32 buf_size)
2691	* Description
2692	* For en eBPF program attached to a perf event, retrieve the
2693	* value of the event counter associated to ctx and store it in
2694	* the structure pointed by buf and of size buf_size. Enabled
2695	* and running times are also stored in the structure (see
2696	* description of helper bpf_perf_event_read_value\ () for
2697	* more details).
2698	* Return
2699	* 0 on success, or a negative error in case of failure.
2700	*
2701	* long bpf_getsockopt(void bpf_socket, int level, int optname, void optval, int optlen)
2702	* Description
2703	* Emulate a call to getsockopt() on the socket associated to
2704	* bpf_socket, which must be a full socket. The level at
2705	* which the option resides and the name optname of the option
2706	* must be specified, see getsockopt(2) for more information.
2707	* The retrieved value is stored in the structure pointed by
2708	* opval and of length optlen.
2709	*
2710	* bpf_socket should be one of the following:
2711	*
2712	* * struct bpf_sock_ops for BPF_PROG_TYPE_SOCK_OPS.
2713	* * struct bpf_sock_addr for BPF_CGROUP_INET4_CONNECT
2714	* and BPF_CGROUP_INET6_CONNECT.
2715	*
2716	* This helper actually implements a subset of getsockopt().
2717	* It supports the following level\ s:
2718	*
2719	* * IPPROTO_TCP, which supports optname
2720	* TCP_CONGESTION.
2721	* * IPPROTO_IP, which supports optname IP_TOS.
2722	* * IPPROTO_IPV6, which supports optname IPV6_TCLASS.
2723	* Return
2724	* 0 on success, or a negative error in case of failure.
2725	*
2726	* long bpf_override_return(struct pt_regs *regs, u64 rc)
2727	* Description
2728	* Used for error injection, this helper uses kprobes to override
2729	* the return value of the probed function, and to set it to rc.
2730	* The first argument is the context regs on which the kprobe
2731	* works.
2732	*
2733	* This helper works by setting the PC (program counter)
2734	* to an override function which is run in place of the original
2735	* probed function. This means the probed function is not run at
2736	* all. The replacement function just returns with the required
2737	* value.
2738	*
2739	* This helper has security implications, and thus is subject to
2740	* restrictions. It is only available if the kernel was compiled
2741	* with the CONFIG_BPF_KPROBE_OVERRIDE configuration
2742	* option, and in this case it only works on functions tagged with
2743	* ALLOW_ERROR_INJECTION in the kernel code.
2744	*
2745	* Also, the helper is only available for the architectures having
2746	* the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2747	* x86 architecture is the only one to support this feature.
2748	* Return
2749	* 0
2750	*
2751	* long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2752	* Description
2753	* Attempt to set the value of the bpf_sock_ops_cb_flags field
2754	* for the full TCP socket associated to bpf_sock_ops to
2755	* argval.
2756	*
2757	* The primary use of this field is to determine if there should
2758	* be calls to eBPF programs of type
2759	* BPF_PROG_TYPE_SOCK_OPS at various points in the TCP
2760	* code. A program of the same type can change its value, per
2761	* connection and as necessary, when the connection is
2762	* established. This field is directly accessible for reading, but
2763	* this helper must be used for updates in order to return an
2764	* error if an eBPF program tries to set a callback that is not
2765	* supported in the current kernel.
2766	*
2767	* argval is a flag array which can combine these flags:
2768	*
2769	* * BPF_SOCK_OPS_RTO_CB_FLAG (retransmission time out)
2770	* * BPF_SOCK_OPS_RETRANS_CB_FLAG (retransmission)
2771	* * BPF_SOCK_OPS_STATE_CB_FLAG (TCP state change)
2772	* * BPF_SOCK_OPS_RTT_CB_FLAG (every RTT)
2773	*
2774	* Therefore, this function can be used to clear a callback flag by
2775	* setting the appropriate bit to zero. e.g. to disable the RTO
2776	* callback:
2777	*
2778	* bpf_sock_ops_cb_flags_set(bpf_sock,
2779	* bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)
2780	*
2781	* Here are some examples of where one could call such eBPF
2782	* program:
2783	*
2784	* * When RTO fires.
2785	* * When a packet is retransmitted.
2786	* * When the connection terminates.
2787	* * When a packet is sent.
2788	* * When a packet is received.
2789	* Return
2790	* Code -EINVAL if the socket is not a full TCP socket;
2791	* otherwise, a positive number containing the bits that could not
2792	* be set is returned (which comes down to 0 if all bits were set
2793	* as required).
2794	*
2795	* long bpf_msg_redirect_map(struct sk_msg_buff msg, struct bpf_map map, u32 key, u64 flags)
2796	* Description
2797	* This helper is used in programs implementing policies at the
2798	* socket level. If the message msg is allowed to pass (i.e. if
2799	* the verdict eBPF program returns SK_PASS), redirect it to
2800	* the socket referenced by map (of type
2801	* BPF_MAP_TYPE_SOCKMAP) at index key. Both ingress and
2802	* egress interfaces can be used for redirection. The
2803	* BPF_F_INGRESS value in flags is used to make the
2804	* distinction (ingress path is selected if the flag is present,
2805	* egress path otherwise). This is the only flag supported for now.
2806	* Return
2807	* SK_PASS on success, or SK_DROP on error.
2808	*
2809	* long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2810	* Description
2811	* For socket policies, apply the verdict of the eBPF program to
2812	* the next bytes (number of bytes) of message msg.
2813	*
2814	* For example, this helper can be used in the following cases:
2815	*
2816	* * A single sendmsg\ () or sendfile\ () system call
2817	* contains multiple logical messages that the eBPF program is
2818	* supposed to read and for which it should apply a verdict.
2819	* * An eBPF program only cares to read the first bytes of a
2820	* msg. If the message has a large payload, then setting up
2821	* and calling the eBPF program repeatedly for all bytes, even
2822	* though the verdict is already known, would create unnecessary
2823	* overhead.
2824	*
2825	* When called from within an eBPF program, the helper sets a
2826	* counter internal to the BPF infrastructure, that is used to
2827	* apply the last verdict to the next bytes. If bytes is
2828	* smaller than the current data being processed from a
2829	* sendmsg\ () or sendfile\ () system call, the first
2830	* bytes will be sent and the eBPF program will be re-run with
2831	* the pointer for start of data pointing to byte number bytes
2832	* + 1. If bytes is larger than the current data being
2833	* processed, then the eBPF verdict will be applied to multiple
2834	* sendmsg\ () or sendfile\ () calls until bytes are
2835	* consumed.
2836	*
2837	* Note that if a socket closes with the internal counter holding
2838	* a non-zero value, this is not a problem because data is not
2839	* being buffered for bytes and is sent as it is received.
2840	* Return
2841	* 0
2842	*
2843	* long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2844	* Description
2845	* For socket policies, prevent the execution of the verdict eBPF
2846	* program for message msg until bytes (byte number) have been
2847	* accumulated.
2848	*
2849	* This can be used when one needs a specific number of bytes
2850	* before a verdict can be assigned, even if the data spans
2851	* multiple sendmsg\ () or sendfile\ () calls. The extreme
2852	* case would be a user calling sendmsg\ () repeatedly with
2853	* 1-byte long message segments. Obviously, this is bad for
2854	* performance, but it is still valid. If the eBPF program needs
2855	* bytes bytes to validate a header, this helper can be used to
2856	* prevent the eBPF program to be called again until bytes have
2857	* been accumulated.
2858	* Return
2859	* 0
2860	*
2861	* long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2862	* Description
2863	* For socket policies, pull in non-linear data from user space
2864	* for msg and set pointers msg\ ->data and msg\
2865	* ->data_end to start and end bytes offsets into msg,
2866	* respectively.
2867	*
2868	* If a program of type BPF_PROG_TYPE_SK_MSG is run on a
2869	* msg it can only parse data that the (data, data_end)
2870	* pointers have already consumed. For sendmsg\ () hooks this
2871	* is likely the first scatterlist element. But for calls relying
2872	* on the sendpage handler (e.g. sendfile\ ()) this will
2873	* be the range (0, 0) because the data is shared with
2874	* user space and by default the objective is to avoid allowing
2875	* user space to modify data while (or after) eBPF verdict is
2876	* being decided. This helper can be used to pull in data and to
2877	* set the start and end pointer to given values. Data will be
2878	* copied if necessary (i.e. if data was not linear and if start
2879	* and end pointers do not point to the same chunk).
2880	*
2881	* A call to this helper is susceptible to change the underlying
2882	* packet buffer. Therefore, at load time, all checks on pointers
2883	* previously done by the verifier are invalidated and must be
2884	* performed again, if the helper is used in combination with
2885	* direct packet access.
2886	*
2887	* All values for flags are reserved for future usage, and must
2888	* be left at zero.
2889	* Return
2890	* 0 on success, or a negative error in case of failure.
2891	*
2892	* long bpf_bind(struct bpf_sock_addr ctx, struct sockaddr addr, int addr_len)
2893	* Description
2894	* Bind the socket associated to ctx to the address pointed by
2895	* addr, of length addr_len. This allows for making outgoing
2896	* connection from the desired IP address, which can be useful for
2897	* example when all processes inside a cgroup should use one
2898	* single IP address on a host that has multiple IP configured.
2899	*
2900	* This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2901	* domain (addr\ ->sa_family) must be AF_INET (or
2902	* AF_INET6). It's advised to pass zero port (sin_port
2903	* or sin6_port) which triggers IP_BIND_ADDRESS_NO_PORT-like
2904	* behavior and lets the kernel efficiently pick up an unused
2905	* port as long as 4-tuple is unique. Passing non-zero port might
2906	* lead to degraded performance.
2907	* Return
2908	* 0 on success, or a negative error in case of failure.
2909	*
2910	* long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2911	* Description
2912	* Adjust (move) xdp_md\ ->data_end by delta bytes. It is
2913	* possible to both shrink and grow the packet tail.
2914	* Shrink done via delta being a negative integer.
2915	*
2916	* A call to this helper is susceptible to change the underlying
2917	* packet buffer. Therefore, at load time, all checks on pointers
2918	* previously done by the verifier are invalidated and must be
2919	* performed again, if the helper is used in combination with
2920	* direct packet access.
2921	* Return
2922	* 0 on success, or a negative error in case of failure.
2923	*
2924	* long bpf_skb_get_xfrm_state(struct sk_buff skb, u32 index, struct bpf_xfrm_state xfrm_state, u32 size, u64 flags)
2925	* Description
2926	* Retrieve the XFRM state (IP transform framework, see also
2927	* ip-xfrm(8)) at index in XFRM "security path" for skb.
2928	*
2929	* The retrieved value is stored in the struct bpf_xfrm_state
2930	* pointed by xfrm_state and of length size.
2931	*
2932	* All values for flags are reserved for future usage, and must
2933	* be left at zero.
2934	*
2935	* This helper is available only if the kernel was compiled with
2936	* CONFIG_XFRM configuration option.
2937	* Return
2938	* 0 on success, or a negative error in case of failure.
2939	*
2940	* long bpf_get_stack(void ctx, void buf, u32 size, u64 flags)
2941	* Description
2942	* Return a user or a kernel stack in bpf program provided buffer.
2943	* To achieve this, the helper needs ctx, which is a pointer
2944	* to the context on which the tracing program is executed.
2945	* To store the stacktrace, the bpf program provides buf with
2946	* a nonnegative size.
2947	*
2948	* The last argument, flags, holds the number of stack frames to
2949	* skip (from 0 to 255), masked with
2950	* BPF_F_SKIP_FIELD_MASK. The next bits can be used to set
2951	* the following flags:
2952	*
2953	* BPF_F_USER_STACK
2954	* Collect a user space stack instead of a kernel stack.
2955	* BPF_F_USER_BUILD_ID
2956	* Collect buildid+offset instead of ips for user stack,
2957	* only valid if BPF_F_USER_STACK is also specified.
2958	*
2959	* bpf_get_stack\ () can collect up to
2960	* PERF_MAX_STACK_DEPTH both kernel and user frames, subject
2961	* to sufficient large buffer size. Note that
2962	* this limit can be controlled with the sysctl program, and
2963	* that it should be manually increased in order to profile long
2964	* user stacks (such as stacks for Java programs). To do so, use:
2965	*
2966	* ::
2967	*
2968	* # sysctl kernel.perf_event_max_stack=<new value>
2969	* Return
2970	* The non-negative copied buf length equal to or less than
2971	* size on success, or a negative error in case of failure.
2972	*
2973	* long bpf_skb_load_bytes_relative(const void skb, u32 offset, void to, u32 len, u32 start_header)
2974	* Description
2975	* This helper is similar to bpf_skb_load_bytes\ () in that
2976	* it provides an easy way to load len bytes from offset
2977	* from the packet associated to skb, into the buffer pointed
2978	* by to. The difference to bpf_skb_load_bytes\ () is that
2979	* a fifth argument start_header exists in order to select a
2980	* base offset to start from. start_header can be one of:
2981	*
2982	* BPF_HDR_START_MAC
2983	* Base offset to load data from is skb's mac header.
2984	* BPF_HDR_START_NET
2985	* Base offset to load data from is skb's network header.
2986	*
2987	* In general, "direct packet access" is the preferred method to
2988	* access packet data, however, this helper is in particular useful
2989	* in socket filters where skb\ ->data does not always point
2990	* to the start of the mac header and where "direct packet access"
2991	* is not available.
2992	* Return
2993	* 0 on success, or a negative error in case of failure.
2994	*
2995	* long bpf_fib_lookup(void ctx, struct bpf_fib_lookup params, int plen, u32 flags)
2996	* Description
2997	* Do FIB lookup in kernel tables using parameters in params.
2998	* If lookup is successful and result shows packet is to be
2999	* forwarded, the neighbor tables are searched for the nexthop.
3000	* If successful (ie., FIB lookup shows forwarding and nexthop
3001	* is resolved), the nexthop address is returned in ipv4_dst
3002	* or ipv6_dst based on family, smac is set to mac address of
3003	* egress device, dmac is set to nexthop mac address, rt_metric
3004	* is set to metric from route (IPv4/IPv6 only), and ifindex
3005	* is set to the device index of the nexthop from the FIB lookup.
3006	*
3007	* plen argument is the size of the passed in struct.
3008	* flags argument can be a combination of one or more of the
3009	* following values:
3010	*
3011	* BPF_FIB_LOOKUP_DIRECT
3012	* Do a direct table lookup vs full lookup using FIB
3013	* rules.
3014	* BPF_FIB_LOOKUP_OUTPUT
3015	* Perform lookup from an egress perspective (default is
3016	* ingress).
3017	*
3018	* ctx is either struct xdp_md for XDP programs or
3019	* struct sk_buff tc cls_act programs.
3020	* Return
3021	* * < 0 if any input argument is invalid
3022	* * 0 on success (packet is forwarded, nexthop neighbor exists)
3023	* * > 0 one of BPF_FIB_LKUP_RET_ codes explaining why the
3024	* packet is not forwarded or needs assist from full stack
3025	*
3026	* If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3027	* was exceeded and output params->mtu_result contains the MTU.
3028	*
3029	* long bpf_sock_hash_update(struct bpf_sock_ops skops, struct bpf_map map, void *key, u64 flags)
3030	* Description
3031	* Add an entry to, or update a sockhash map referencing sockets.
3032	* The skops is used as a new value for the entry associated to
3033	* key. flags is one of:
3034	*
3035	* BPF_NOEXIST
3036	* The entry for key must not exist in the map.
3037	* BPF_EXIST
3038	* The entry for key must already exist in the map.
3039	* BPF_ANY
3040	* No condition on the existence of the entry for key.
3041	*
3042	* If the map has eBPF programs (parser and verdict), those will
3043	* be inherited by the socket being added. If the socket is
3044	* already attached to eBPF programs, this results in an error.
3045	* Return
3046	* 0 on success, or a negative error in case of failure.
3047	*
3048	* long bpf_msg_redirect_hash(struct sk_msg_buff msg, struct bpf_map map, void *key, u64 flags)
3049	* Description
3050	* This helper is used in programs implementing policies at the
3051	* socket level. If the message msg is allowed to pass (i.e. if
3052	* the verdict eBPF program returns SK_PASS), redirect it to
3053	* the socket referenced by map (of type
3054	* BPF_MAP_TYPE_SOCKHASH) using hash key. Both ingress and
3055	* egress interfaces can be used for redirection. The
3056	* BPF_F_INGRESS value in flags is used to make the
3057	* distinction (ingress path is selected if the flag is present,
3058	* egress path otherwise). This is the only flag supported for now.
3059	* Return
3060	* SK_PASS on success, or SK_DROP on error.
3061	*
3062	* long bpf_sk_redirect_hash(struct sk_buff skb, struct bpf_map map, void *key, u64 flags)
3063	* Description
3064	* This helper is used in programs implementing policies at the
3065	* skb socket level. If the sk_buff skb is allowed to pass (i.e.
3066	* if the verdict eBPF program returns SK_PASS), redirect it
3067	* to the socket referenced by map (of type
3068	* BPF_MAP_TYPE_SOCKHASH) using hash key. Both ingress and
3069	* egress interfaces can be used for redirection. The
3070	* BPF_F_INGRESS value in flags is used to make the
3071	* distinction (ingress path is selected if the flag is present,
3072	* egress otherwise). This is the only flag supported for now.
3073	* Return
3074	* SK_PASS on success, or SK_DROP on error.
3075	*
3076	* long bpf_lwt_push_encap(struct sk_buff skb, u32 type, void hdr, u32 len)
3077	* Description
3078	* Encapsulate the packet associated to skb within a Layer 3
3079	* protocol header. This header is provided in the buffer at
3080	* address hdr, with len its size in bytes. type indicates
3081	* the protocol of the header and can be one of:
3082	*
3083	* BPF_LWT_ENCAP_SEG6
3084	* IPv6 encapsulation with Segment Routing Header
3085	* (struct ipv6_sr_hdr). hdr only contains the SRH,
3086	* the IPv6 header is computed by the kernel.
3087	* BPF_LWT_ENCAP_SEG6_INLINE
3088	* Only works if skb contains an IPv6 packet. Insert a
3089	* Segment Routing Header (struct ipv6_sr_hdr) inside
3090	* the IPv6 header.
3091	* BPF_LWT_ENCAP_IP
3092	* IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3093	* must be IPv4 or IPv6, followed by zero or more
3094	* additional headers, up to LWT_BPF_MAX_HEADROOM
3095	* total bytes in all prepended headers. Please note that
3096	* if skb_is_gso\ (skb) is true, no more than two
3097	* headers can be prepended, and the inner header, if
3098	* present, should be either GRE or UDP/GUE.
3099	*
3100	* BPF_LWT_ENCAP_SEG6\ \* types can be called by BPF programs
3101	* of type BPF_PROG_TYPE_LWT_IN; BPF_LWT_ENCAP_IP type can
3102	* be called by bpf programs of types BPF_PROG_TYPE_LWT_IN and
3103	* BPF_PROG_TYPE_LWT_XMIT.
3104	*
3105	* A call to this helper is susceptible to change the underlying
3106	* packet buffer. Therefore, at load time, all checks on pointers
3107	* previously done by the verifier are invalidated and must be
3108	* performed again, if the helper is used in combination with
3109	* direct packet access.
3110	* Return
3111	* 0 on success, or a negative error in case of failure.
3112	*
3113	* long bpf_lwt_seg6_store_bytes(struct sk_buff skb, u32 offset, const void from, u32 len)
3114	* Description
3115	* Store len bytes from address from into the packet
3116	* associated to skb, at offset. Only the flags, tag and TLVs
3117	* inside the outermost IPv6 Segment Routing Header can be
3118	* modified through this helper.
3119	*
3120	* A call to this helper is susceptible to change the underlying
3121	* packet buffer. Therefore, at load time, all checks on pointers
3122	* previously done by the verifier are invalidated and must be
3123	* performed again, if the helper is used in combination with
3124	* direct packet access.
3125	* Return
3126	* 0 on success, or a negative error in case of failure.
3127	*
3128	* long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3129	* Description
3130	* Adjust the size allocated to TLVs in the outermost IPv6
3131	* Segment Routing Header contained in the packet associated to
3132	* skb, at position offset by delta bytes. Only offsets
3133	* after the segments are accepted. delta can be as well
3134	* positive (growing) as negative (shrinking).
3135	*
3136	* A call to this helper is susceptible to change the underlying
3137	* packet buffer. Therefore, at load time, all checks on pointers
3138	* previously done by the verifier are invalidated and must be
3139	* performed again, if the helper is used in combination with
3140	* direct packet access.
3141	* Return
3142	* 0 on success, or a negative error in case of failure.
3143	*
3144	* long bpf_lwt_seg6_action(struct sk_buff skb, u32 action, void param, u32 param_len)
3145	* Description
3146	* Apply an IPv6 Segment Routing action of type action to the
3147	* packet associated to skb. Each action takes a parameter
3148	* contained at address param, and of length param_len bytes.
3149	* action can be one of:
3150	*
3151	* SEG6_LOCAL_ACTION_END_X
3152	* End.X action: Endpoint with Layer-3 cross-connect.
3153	* Type of param: struct in6_addr.
3154	* SEG6_LOCAL_ACTION_END_T
3155	* End.T action: Endpoint with specific IPv6 table lookup.
3156	* Type of param: int.
3157	* SEG6_LOCAL_ACTION_END_B6
3158	* End.B6 action: Endpoint bound to an SRv6 policy.
3159	* Type of param: struct ipv6_sr_hdr.
3160	* SEG6_LOCAL_ACTION_END_B6_ENCAP
3161	* End.B6.Encap action: Endpoint bound to an SRv6
3162	* encapsulation policy.
3163	* Type of param: struct ipv6_sr_hdr.
3164	*
3165	* A call to this helper is susceptible to change the underlying
3166	* packet buffer. Therefore, at load time, all checks on pointers
3167	* previously done by the verifier are invalidated and must be
3168	* performed again, if the helper is used in combination with
3169	* direct packet access.
3170	* Return
3171	* 0 on success, or a negative error in case of failure.
3172	*
3173	* long bpf_rc_repeat(void *ctx)
3174	* Description
3175	* This helper is used in programs implementing IR decoding, to
3176	* report a successfully decoded repeat key message. This delays
3177	* the generation of a key up event for previously generated
3178	* key down event.
3179	*
3180	* Some IR protocols like NEC have a special IR message for
3181	* repeating last button, for when a button is held down.
3182	*
3183	* The ctx should point to the lirc sample as passed into
3184	* the program.
3185	*
3186	* This helper is only available is the kernel was compiled with
3187	* the CONFIG_BPF_LIRC_MODE2 configuration option set to
3188	* "y".
3189	* Return
3190	* 0
3191	*
3192	* long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3193	* Description
3194	* This helper is used in programs implementing IR decoding, to
3195	* report a successfully decoded key press with scancode,
3196	* toggle value in the given protocol. The scancode will be
3197	* translated to a keycode using the rc keymap, and reported as
3198	* an input key down event. After a period a key up event is
3199	* generated. This period can be extended by calling either
3200	* bpf_rc_keydown\ () again with the same values, or calling
3201	* bpf_rc_repeat\ ().
3202	*
3203	* Some protocols include a toggle bit, in case the button was
3204	* released and pressed again between consecutive scancodes.
3205	*
3206	* The ctx should point to the lirc sample as passed into
3207	* the program.
3208	*
3209	* The protocol is the decoded protocol number (see
3210	* enum rc_proto for some predefined values).
3211	*
3212	* This helper is only available is the kernel was compiled with
3213	* the CONFIG_BPF_LIRC_MODE2 configuration option set to
3214	* "y".
3215	* Return
3216	* 0
3217	*
3218	* u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3219	* Description
3220	* Return the cgroup v2 id of the socket associated with the skb.
3221	* This is roughly similar to the bpf_get_cgroup_classid\ ()
3222	* helper for cgroup v1 by providing a tag resp. identifier that
3223	* can be matched on or used for map lookups e.g. to implement
3224	* policy. The cgroup v2 id of a given path in the hierarchy is
3225	* exposed in user space through the f_handle API in order to get
3226	* to the same 64-bit id.
3227	*
3228	* This helper can be used on TC egress path, but not on ingress,
3229	* and is available only if the kernel was compiled with the
3230	* CONFIG_SOCK_CGROUP_DATA configuration option.
3231	* Return
3232	* The id is returned or 0 in case the id could not be retrieved.
3233	*
3234	* u64 bpf_get_current_cgroup_id(void)
3235	* Return
3236	* A 64-bit integer containing the current cgroup id based
3237	* on the cgroup within which the current task is running.
3238	*
3239	* void bpf_get_local_storage(void map, u64 flags)
3240	* Description
3241	* Get the pointer to the local storage area.
3242	* The type and the size of the local storage is defined
3243	* by the map argument.
3244	* The flags meaning is specific for each map type,
3245	* and has to be 0 for cgroup local storage.
3246	*
3247	* Depending on the BPF program type, a local storage area
3248	* can be shared between multiple instances of the BPF program,
3249	* running simultaneously.
3250	*
3251	* A user should care about the synchronization by himself.
3252	* For example, by using the BPF_ATOMIC instructions to alter
3253	* the shared data.
3254	* Return
3255	* A pointer to the local storage area.
3256	*
3257	* long bpf_sk_select_reuseport(struct sk_reuseport_md reuse, struct bpf_map map, void *key, u64 flags)
3258	* Description
3259	* Select a SO_REUSEPORT socket from a
3260	* BPF_MAP_TYPE_REUSEPORT_SOCKARRAY map.
3261	* It checks the selected socket is matching the incoming
3262	* request in the socket buffer.
3263	* Return
3264	* 0 on success, or a negative error in case of failure.
3265	*
3266	* u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3267	* Description
3268	* Return id of cgroup v2 that is ancestor of cgroup associated
3269	* with the skb at the ancestor_level. The root cgroup is at
3270	* ancestor_level zero and each step down the hierarchy
3271	* increments the level. If ancestor_level == level of cgroup
3272	* associated with skb, then return value will be same as that
3273	* of bpf_skb_cgroup_id\ ().
3274	*
3275	* The helper is useful to implement policies based on cgroups
3276	* that are upper in hierarchy than immediate cgroup associated
3277	* with skb.
3278	*
3279	* The format of returned id and helper limitations are same as in
3280	* bpf_skb_cgroup_id\ ().
3281	* Return
3282	* The id is returned or 0 in case the id could not be retrieved.
3283	*
3284	* struct bpf_sock bpf_sk_lookup_tcp(void ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3285	* Description
3286	* Look for TCP socket matching tuple, optionally in a child
3287	* network namespace netns. The return value must be checked,
3288	* and if non-NULL, released via bpf_sk_release\ ().
3289	*
3290	* The ctx should point to the context of the program, such as
3291	* the skb or socket (depending on the hook in use). This is used
3292	* to determine the base network namespace for the lookup.
3293	*
3294	* tuple_size must be one of:
3295	*
3296	* sizeof\ (tuple\ ->ipv4)
3297	* Look for an IPv4 socket.
3298	* sizeof\ (tuple\ ->ipv6)
3299	* Look for an IPv6 socket.
3300	*
3301	* If the netns is a negative signed 32-bit integer, then the
3302	* socket lookup table in the netns associated with the ctx
3303	* will be used. For the TC hooks, this is the netns of the device
3304	* in the skb. For socket hooks, this is the netns of the socket.
3305	* If netns is any other signed 32-bit value greater than or
3306	* equal to zero then it specifies the ID of the netns relative to
3307	* the netns associated with the ctx. netns values beyond the
3308	* range of 32-bit integers are reserved for future use.
3309	*
3310	* All values for flags are reserved for future usage, and must
3311	* be left at zero.
3312	*
3313	* This helper is available only if the kernel was compiled with
3314	* CONFIG_NET configuration option.
3315	* Return
3316	* Pointer to struct bpf_sock, or NULL in case of failure.
3317	* For sockets with reuseport option, the struct bpf_sock
3318	* result is from reuse\ ->socks\ [] using the hash of the
3319	* tuple.
3320	*
3321	* struct bpf_sock bpf_sk_lookup_udp(void ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3322	* Description
3323	* Look for UDP socket matching tuple, optionally in a child
3324	* network namespace netns. The return value must be checked,
3325	* and if non-NULL, released via bpf_sk_release\ ().
3326	*
3327	* The ctx should point to the context of the program, such as
3328	* the skb or socket (depending on the hook in use). This is used
3329	* to determine the base network namespace for the lookup.
3330	*
3331	* tuple_size must be one of:
3332	*
3333	* sizeof\ (tuple\ ->ipv4)
3334	* Look for an IPv4 socket.
3335	* sizeof\ (tuple\ ->ipv6)
3336	* Look for an IPv6 socket.
3337	*
3338	* If the netns is a negative signed 32-bit integer, then the
3339	* socket lookup table in the netns associated with the ctx
3340	* will be used. For the TC hooks, this is the netns of the device
3341	* in the skb. For socket hooks, this is the netns of the socket.
3342	* If netns is any other signed 32-bit value greater than or
3343	* equal to zero then it specifies the ID of the netns relative to
3344	* the netns associated with the ctx. netns values beyond the
3345	* range of 32-bit integers are reserved for future use.
3346	*
3347	* All values for flags are reserved for future usage, and must
3348	* be left at zero.
3349	*
3350	* This helper is available only if the kernel was compiled with
3351	* CONFIG_NET configuration option.
3352	* Return
3353	* Pointer to struct bpf_sock, or NULL in case of failure.
3354	* For sockets with reuseport option, the struct bpf_sock
3355	* result is from reuse\ ->socks\ [] using the hash of the
3356	* tuple.
3357	*
3358	* long bpf_sk_release(void *sock)
3359	* Description
3360	* Release the reference held by sock. sock must be a
3361	* non-NULL pointer that was returned from
3362	* bpf_sk_lookup_xxx\ ().
3363	* Return
3364	* 0 on success, or a negative error in case of failure.
3365	*
3366	* long bpf_map_push_elem(struct bpf_map map, const void value, u64 flags)
3367	* Description
3368	* Push an element value in map. flags is one of:
3369	*
3370	* BPF_EXIST
3371	* If the queue/stack is full, the oldest element is
3372	* removed to make room for this.
3373	* Return
3374	* 0 on success, or a negative error in case of failure.
3375	*
3376	* long bpf_map_pop_elem(struct bpf_map map, void value)
3377	* Description
3378	* Pop an element from map.
3379	* Return
3380	* 0 on success, or a negative error in case of failure.
3381	*
3382	* long bpf_map_peek_elem(struct bpf_map map, void value)
3383	* Description
3384	* Get an element from map without removing it.
3385	* Return
3386	* 0 on success, or a negative error in case of failure.
3387	*
3388	* long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3389	* Description
3390	* For socket policies, insert len bytes into msg at offset
3391	* start.
3392	*
3393	* If a program of type BPF_PROG_TYPE_SK_MSG is run on a
3394	* msg it may want to insert metadata or options into the msg.
3395	* This can later be read and used by any of the lower layer BPF
3396	* hooks.
3397	*
3398	* This helper may fail if under memory pressure (a malloc
3399	* fails) in these cases BPF programs will get an appropriate
3400	* error and BPF programs will need to handle them.
3401	* Return
3402	* 0 on success, or a negative error in case of failure.
3403	*
3404	* long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3405	* Description
3406	* Will remove len bytes from a msg starting at byte start.
3407	* This may result in ENOMEM errors under certain situations if
3408	* an allocation and copy are required due to a full ring buffer.
3409	* However, the helper will try to avoid doing the allocation
3410	* if possible. Other errors can occur if input parameters are
3411	* invalid either due to start byte not being valid part of msg
3412	* payload and/or pop value being to large.
3413	* Return
3414	* 0 on success, or a negative error in case of failure.
3415	*
3416	* long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3417	* Description
3418	* This helper is used in programs implementing IR decoding, to
3419	* report a successfully decoded pointer movement.
3420	*
3421	* The ctx should point to the lirc sample as passed into
3422	* the program.
3423	*
3424	* This helper is only available is the kernel was compiled with
3425	* the CONFIG_BPF_LIRC_MODE2 configuration option set to
3426	* "y".
3427	* Return
3428	* 0
3429	*
3430	* long bpf_spin_lock(struct bpf_spin_lock *lock)
3431	* Description
3432	* Acquire a spinlock represented by the pointer lock, which is
3433	* stored as part of a value of a map. Taking the lock allows to
3434	* safely update the rest of the fields in that value. The
3435	* spinlock can (and must) later be released with a call to
3436	* bpf_spin_unlock\ (\ lock\ ).
3437	*
3438	* Spinlocks in BPF programs come with a number of restrictions
3439	* and constraints:
3440	*
3441	* * bpf_spin_lock objects are only allowed inside maps of
3442	* types BPF_MAP_TYPE_HASH and BPF_MAP_TYPE_ARRAY (this
3443	* list could be extended in the future).
3444	* * BTF description of the map is mandatory.
3445	* * The BPF program can take ONE lock at a time, since taking two
3446	* or more could cause dead locks.
3447	* * Only one struct bpf_spin_lock is allowed per map element.
3448	* * When the lock is taken, calls (either BPF to BPF or helpers)
3449	* are not allowed.
3450	* * The BPF_LD_ABS and BPF_LD_IND instructions are not
3451	* allowed inside a spinlock-ed region.
3452	* * The BPF program MUST call bpf_spin_unlock\ () to release
3453	* the lock, on all execution paths, before it returns.
3454	* * The BPF program can access struct bpf_spin_lock only via
3455	* the bpf_spin_lock\ () and bpf_spin_unlock\ ()
3456	* helpers. Loading or storing data into the **struct
3457	* bpf_spin_lock** lock\ ; field of a map is not allowed.
3458	* * To use the bpf_spin_lock\ () helper, the BTF description
3459	* of the map value must be a struct and have **struct
3460	* bpf_spin_lock** anyname\ ; field at the top level.
3461	* Nested lock inside another struct is not allowed.
3462	* * The struct bpf_spin_lock lock field in a map value must
3463	* be aligned on a multiple of 4 bytes in that value.
3464	* * Syscall with command BPF_MAP_LOOKUP_ELEM does not copy
3465	* the bpf_spin_lock field to user space.
3466	* * Syscall with command BPF_MAP_UPDATE_ELEM, or update from
3467	* a BPF program, do not update the bpf_spin_lock field.
3468	* * bpf_spin_lock cannot be on the stack or inside a
3469	* networking packet (it can only be inside of a map values).
3470	* * bpf_spin_lock is available to root only.
3471	* * Tracing programs and socket filter programs cannot use
3472	* bpf_spin_lock\ () due to insufficient preemption checks
3473	* (but this may change in the future).
3474	* * bpf_spin_lock is not allowed in inner maps of map-in-map.
3475	* Return
3476	* 0
3477	*
3478	* long bpf_spin_unlock(struct bpf_spin_lock *lock)
3479	* Description
3480	* Release the lock previously locked by a call to
3481	* bpf_spin_lock\ (\ lock\ ).
3482	* Return
3483	* 0
3484	*
3485	* struct bpf_sock bpf_sk_fullsock(struct bpf_sock sk)
3486	* Description
3487	* This helper gets a struct bpf_sock pointer such
3488	* that all the fields in this bpf_sock can be accessed.
3489	* Return
3490	* A struct bpf_sock pointer on success, or NULL in
3491	* case of failure.
3492	*
3493	* struct bpf_tcp_sock bpf_tcp_sock(struct bpf_sock sk)
3494	* Description
3495	* This helper gets a struct bpf_tcp_sock pointer from a
3496	* struct bpf_sock pointer.
3497	* Return
3498	* A struct bpf_tcp_sock pointer on success, or NULL in
3499	* case of failure.
3500	*
3501	* long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3502	* Description
3503	* Set ECN (Explicit Congestion Notification) field of IP header
3504	* to CE (Congestion Encountered) if current value is ECT
3505	* (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3506	* and IPv4.
3507	* Return
3508	* 1 if the CE flag is set (either by the current helper call
3509	* or because it was already present), 0 if it is not set.
3510	*
3511	* struct bpf_sock bpf_get_listener_sock(struct bpf_sock sk)
3512	* Description
3513	* Return a struct bpf_sock pointer in TCP_LISTEN state.
3514	* bpf_sk_release\ () is unnecessary and not allowed.
3515	* Return
3516	* A struct bpf_sock pointer on success, or NULL in
3517	* case of failure.
3518	*
3519	* struct bpf_sock bpf_skc_lookup_tcp(void ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3520	* Description
3521	* Look for TCP socket matching tuple, optionally in a child
3522	* network namespace netns. The return value must be checked,
3523	* and if non-NULL, released via bpf_sk_release\ ().
3524	*
3525	* This function is identical to bpf_sk_lookup_tcp\ (), except
3526	* that it also returns timewait or request sockets. Use
3527	* bpf_sk_fullsock\ () or bpf_tcp_sock\ () to access the
3528	* full structure.
3529	*
3530	* This helper is available only if the kernel was compiled with
3531	* CONFIG_NET configuration option.
3532	* Return
3533	* Pointer to struct bpf_sock, or NULL in case of failure.
3534	* For sockets with reuseport option, the struct bpf_sock
3535	* result is from reuse\ ->socks\ [] using the hash of the
3536	* tuple.
3537	*
3538	* long bpf_tcp_check_syncookie(void sk, void iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3539	* Description
3540	* Check whether iph and th contain a valid SYN cookie ACK for
3541	* the listening socket in sk.
3542	*
3543	* iph points to the start of the IPv4 or IPv6 header, while
3544	* iph_len contains sizeof\ (struct iphdr) or
3545	* sizeof\ (struct ip6hdr).
3546	*
3547	* th points to the start of the TCP header, while th_len
3548	* contains sizeof\ (struct tcphdr).
3549	* Return
3550	* 0 if iph and th are a valid SYN cookie ACK, or a negative
3551	* error otherwise.
3552	*
3553	* long bpf_sysctl_get_name(struct bpf_sysctl ctx, char buf, size_t buf_len, u64 flags)
3554	* Description
3555	* Get name of sysctl in /proc/sys/ and copy it into provided by
3556	* program buffer buf of size buf_len.
3557	*
3558	* The buffer is always NUL terminated, unless it's zero-sized.
3559	*
3560	* If flags is zero, full name (e.g. "net/ipv4/tcp_mem") is
3561	* copied. Use BPF_F_SYSCTL_BASE_NAME flag to copy base name
3562	* only (e.g. "tcp_mem").
3563	* Return
3564	* Number of character copied (not including the trailing NUL).
3565	*
3566	* -E2BIG if the buffer wasn't big enough (buf will contain
3567	* truncated name in this case).
3568	*
3569	* long bpf_sysctl_get_current_value(struct bpf_sysctl ctx, char buf, size_t buf_len)
3570	* Description
3571	* Get current value of sysctl as it is presented in /proc/sys
3572	* (incl. newline, etc), and copy it as a string into provided
3573	* by program buffer buf of size buf_len.
3574	*
3575	* The whole value is copied, no matter what file position user
3576	* space issued e.g. sys_read at.
3577	*
3578	* The buffer is always NUL terminated, unless it's zero-sized.
3579	* Return
3580	* Number of character copied (not including the trailing NUL).
3581	*
3582	* -E2BIG if the buffer wasn't big enough (buf will contain
3583	* truncated name in this case).
3584	*
3585	* -EINVAL if current value was unavailable, e.g. because
3586	* sysctl is uninitialized and read returns -EIO for it.
3587	*
3588	* long bpf_sysctl_get_new_value(struct bpf_sysctl ctx, char buf, size_t buf_len)
3589	* Description
3590	* Get new value being written by user space to sysctl (before
3591	* the actual write happens) and copy it as a string into
3592	* provided by program buffer buf of size buf_len.
3593	*
3594	* User space may write new value at file position > 0.
3595	*
3596	* The buffer is always NUL terminated, unless it's zero-sized.
3597	* Return
3598	* Number of character copied (not including the trailing NUL).
3599	*
3600	* -E2BIG if the buffer wasn't big enough (buf will contain
3601	* truncated name in this case).
3602	*
3603	* -EINVAL if sysctl is being read.
3604	*
3605	* long bpf_sysctl_set_new_value(struct bpf_sysctl ctx, const char buf, size_t buf_len)
3606	* Description
3607	* Override new value being written by user space to sysctl with
3608	* value provided by program in buffer buf of size buf_len.
3609	*
3610	* buf should contain a string in same form as provided by user
3611	* space on sysctl write.
3612	*
3613	* User space may write new value at file position > 0. To override
3614	* the whole sysctl value file position should be set to zero.
3615	* Return
3616	* 0 on success.
3617	*
3618	* -E2BIG if the buf_len is too big.
3619	*
3620	* -EINVAL if sysctl is being read.
3621	*
3622	* long bpf_strtol(const char buf, size_t buf_len, u64 flags, long res)
3623	* Description
3624	* Convert the initial part of the string from buffer buf of
3625	* size buf_len to a long integer according to the given base
3626	* and save the result in res.
3627	*
3628	* The string may begin with an arbitrary amount of white space
3629	* (as determined by isspace\ (3)) followed by a single
3630	* optional '-' sign.
3631	*
3632	* Five least significant bits of flags encode base, other bits
3633	* are currently unused.
3634	*
3635	* Base must be either 8, 10, 16 or 0 to detect it automatically
3636	* similar to user space strtol\ (3).
3637	* Return
3638	* Number of characters consumed on success. Must be positive but
3639	* no more than buf_len.
3640	*
3641	* -EINVAL if no valid digits were found or unsupported base
3642	* was provided.
3643	*
3644	* -ERANGE if resulting value was out of range.
3645	*
3646	* long bpf_strtoul(const char buf, size_t buf_len, u64 flags, unsigned long res)
3647	* Description
3648	* Convert the initial part of the string from buffer buf of
3649	* size buf_len to an unsigned long integer according to the
3650	* given base and save the result in res.
3651	*
3652	* The string may begin with an arbitrary amount of white space
3653	* (as determined by isspace\ (3)).
3654	*
3655	* Five least significant bits of flags encode base, other bits
3656	* are currently unused.
3657	*
3658	* Base must be either 8, 10, 16 or 0 to detect it automatically
3659	* similar to user space strtoul\ (3).
3660	* Return
3661	* Number of characters consumed on success. Must be positive but
3662	* no more than buf_len.
3663	*
3664	* -EINVAL if no valid digits were found or unsupported base
3665	* was provided.
3666	*
3667	* -ERANGE if resulting value was out of range.
3668	*
3669	* void bpf_sk_storage_get(struct bpf_map map, void sk, void value, u64 flags)
3670	* Description
3671	* Get a bpf-local-storage from a sk.
3672	*
3673	* Logically, it could be thought of getting the value from
3674	* a map with sk as the key. From this
3675	* perspective, the usage is not much different from
3676	* bpf_map_lookup_elem\ (map, &\ sk) except this
3677	* helper enforces the key must be a full socket and the map must
3678	* be a BPF_MAP_TYPE_SK_STORAGE also.
3679	*
3680	* Underneath, the value is stored locally at sk instead of
3681	* the map. The map is used as the bpf-local-storage
3682	* "type". The bpf-local-storage "type" (i.e. the map) is
3683	* searched against all bpf-local-storages residing at sk.
3684	*
3685	* sk is a kernel struct sock pointer for LSM program.
3686	* sk is a struct bpf_sock pointer for other program types.
3687	*
3688	* An optional flags (BPF_SK_STORAGE_GET_F_CREATE) can be
3689	* used such that a new bpf-local-storage will be
3690	* created if one does not exist. value can be used
3691	* together with BPF_SK_STORAGE_GET_F_CREATE to specify
3692	* the initial value of a bpf-local-storage. If value is
3693	* NULL, the new bpf-local-storage will be zero initialized.
3694	* Return
3695	* A bpf-local-storage pointer is returned on success.
3696	*
3697	* NULL if not found or there was an error in adding
3698	* a new bpf-local-storage.
3699	*
3700	* long bpf_sk_storage_delete(struct bpf_map map, void sk)
3701	* Description
3702	* Delete a bpf-local-storage from a sk.
3703	* Return
3704	* 0 on success.
3705	*
3706	* -ENOENT if the bpf-local-storage cannot be found.
3707	* -EINVAL if sk is not a fullsock (e.g. a request_sock).
3708	*
3709	* long bpf_send_signal(u32 sig)
3710	* Description
3711	* Send signal sig to the process of the current task.
3712	* The signal may be delivered to any of this process's threads.
3713	* Return
3714	* 0 on success or successfully queued.
3715	*
3716	* -EBUSY if work queue under nmi is full.
3717	*
3718	* -EINVAL if sig is invalid.
3719	*
3720	* -EPERM if no permission to send the sig.
3721	*
3722	* -EAGAIN if bpf program can try again.
3723	*
3724	* s64 bpf_tcp_gen_syncookie(void sk, void iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3725	* Description
3726	* Try to issue a SYN cookie for the packet with corresponding
3727	* IP/TCP headers, iph and th, on the listening socket in sk.
3728	*
3729	* iph points to the start of the IPv4 or IPv6 header, while
3730	* iph_len contains sizeof\ (struct iphdr) or
3731	* sizeof\ (struct ip6hdr).
3732	*
3733	* th points to the start of the TCP header, while th_len
3734	* contains the length of the TCP header.
3735	* Return
3736	* On success, lower 32 bits hold the generated SYN cookie in
3737	* followed by 16 bits which hold the MSS value for that cookie,
3738	* and the top 16 bits are unused.
3739	*
3740	* On failure, the returned value is one of the following:
3741	*
3742	* -EINVAL SYN cookie cannot be issued due to error
3743	*
3744	* -ENOENT SYN cookie should not be issued (no SYN flood)
3745	*
3746	* -EOPNOTSUPP kernel configuration does not enable SYN cookies
3747	*
3748	* -EPROTONOSUPPORT IP packet version is not 4 or 6
3749	*
3750	* long bpf_skb_output(void ctx, struct bpf_map map, u64 flags, void *data, u64 size)
3751	* Description
3752	* Write raw data blob into a special BPF perf event held by
3753	* map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY. This perf
3754	* event must have the following attributes: PERF_SAMPLE_RAW
3755	* as sample_type, PERF_TYPE_SOFTWARE as type, and
3756	* PERF_COUNT_SW_BPF_OUTPUT as config.
3757	*
3758	* The flags are used to indicate the index in map for which
3759	* the value must be put, masked with BPF_F_INDEX_MASK.
3760	* Alternatively, flags can be set to BPF_F_CURRENT_CPU
3761	* to indicate that the index of the current CPU core should be
3762	* used.
3763	*
3764	* The value to write, of size, is passed through eBPF stack and
3765	* pointed by data.
3766	*
3767	* ctx is a pointer to in-kernel struct sk_buff.
3768	*
3769	* This helper is similar to bpf_perf_event_output\ () but
3770	* restricted to raw_tracepoint bpf programs.
3771	* Return
3772	* 0 on success, or a negative error in case of failure.
3773	*
3774	* long bpf_probe_read_user(void dst, u32 size, const void unsafe_ptr)
3775	* Description
3776	* Safely attempt to read size bytes from user space address
3777	* unsafe_ptr and store the data in dst.
3778	* Return
3779	* 0 on success, or a negative error in case of failure.
3780	*
3781	* long bpf_probe_read_kernel(void dst, u32 size, const void unsafe_ptr)
3782	* Description
3783	* Safely attempt to read size bytes from kernel space address
3784	* unsafe_ptr and store the data in dst.
3785	* Return
3786	* 0 on success, or a negative error in case of failure.
3787	*
3788	* long bpf_probe_read_user_str(void dst, u32 size, const void unsafe_ptr)
3789	* Description
3790	* Copy a NUL terminated string from an unsafe user address
3791	* unsafe_ptr to dst. The size should include the
3792	* terminating NUL byte. In case the string length is smaller than
3793	* size, the target is not padded with further NUL bytes. If the
3794	* string length is larger than size, just size-1 bytes are
3795	* copied and the last byte is set to NUL.
3796	*
3797	* On success, returns the number of bytes that were written,
3798	* including the terminal NUL. This makes this helper useful in
3799	* tracing programs for reading strings, and more importantly to
3800	* get its length at runtime. See the following snippet:
3801	*
3802	* ::
3803	*
3804	* SEC("kprobe/sys_open")
3805	* void bpf_sys_open(struct pt_regs *ctx)
3806	* {
3807	* char buf[PATHLEN]; // PATHLEN is defined to 256
3808	* int res = bpf_probe_read_user_str(buf, sizeof(buf),
3809	* ctx->di);
3810	*
3811	* // Consume buf, for example push it to
3812	* // userspace via bpf_perf_event_output(); we
3813	* // can use res (the string length) as event
3814	* // size, after checking its boundaries.
3815	* }
3816	*
3817	* In comparison, using bpf_probe_read_user\ () helper here
3818	* instead to read the string would require to estimate the length
3819	* at compile time, and would often result in copying more memory
3820	* than necessary.
3821	*
3822	* Another useful use case is when parsing individual process
3823	* arguments or individual environment variables navigating
3824	* current\ ->mm->arg_start and current\
3825	* ->mm->env_start: using this helper and the return value,
3826	* one can quickly iterate at the right offset of the memory area.
3827	* Return
3828	* On success, the strictly positive length of the output string,
3829	* including the trailing NUL character. On error, a negative
3830	* value.
3831	*
3832	* long bpf_probe_read_kernel_str(void dst, u32 size, const void unsafe_ptr)
3833	* Description
3834	* Copy a NUL terminated string from an unsafe kernel address unsafe_ptr
3835	* to dst. Same semantics as with bpf_probe_read_user_str\ () apply.
3836	* Return
3837	* On success, the strictly positive length of the string, including
3838	* the trailing NUL character. On error, a negative value.
3839	*
3840	* long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3841	* Description
3842	* Send out a tcp-ack. tp is the in-kernel struct tcp_sock.
3843	* rcv_nxt is the ack_seq to be sent out.
3844	* Return
3845	* 0 on success, or a negative error in case of failure.
3846	*
3847	* long bpf_send_signal_thread(u32 sig)
3848	* Description
3849	* Send signal sig to the thread corresponding to the current task.
3850	* Return
3851	* 0 on success or successfully queued.
3852	*
3853	* -EBUSY if work queue under nmi is full.
3854	*
3855	* -EINVAL if sig is invalid.
3856	*
3857	* -EPERM if no permission to send the sig.
3858	*
3859	* -EAGAIN if bpf program can try again.
3860	*
3861	* u64 bpf_jiffies64(void)
3862	* Description
3863	* Obtain the 64bit jiffies
3864	* Return
3865	* The 64 bit jiffies
3866	*
3867	* long bpf_read_branch_records(struct bpf_perf_event_data ctx, void buf, u32 size, u64 flags)
3868	* Description
3869	* For an eBPF program attached to a perf event, retrieve the
3870	* branch records (struct perf_branch_entry) associated to ctx
3871	* and store it in the buffer pointed by buf up to size
3872	* size bytes.
3873	* Return
3874	* On success, number of bytes written to buf. On error, a
3875	* negative value.
3876	*
3877	* The flags can be set to BPF_F_GET_BRANCH_RECORDS_SIZE to
3878	* instead return the number of bytes required to store all the
3879	* branch entries. If this flag is set, buf may be NULL.
3880	*
3881	* -EINVAL if arguments invalid or size not a multiple
3882	* of sizeof\ (struct perf_branch_entry\ ).
3883	*
3884	* -ENOENT if architecture does not support branch records.
3885	*
3886	* long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3887	* Description
3888	* Returns 0 on success, values for pid and tgid as seen from the current
3889	* namespace will be returned in nsdata.
3890	* Return
3891	* 0 on success, or one of the following in case of failure:
3892	*
3893	* -EINVAL if dev and inum supplied don't match dev_t and inode number
3894	* with nsfs of current task, or if dev conversion to dev_t lost high bits.
3895	*
3896	* -ENOENT if pidns does not exists for the current task.
3897	*
3898	* long bpf_xdp_output(void ctx, struct bpf_map map, u64 flags, void *data, u64 size)
3899	* Description
3900	* Write raw data blob into a special BPF perf event held by
3901	* map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY. This perf
3902	* event must have the following attributes: PERF_SAMPLE_RAW
3903	* as sample_type, PERF_TYPE_SOFTWARE as type, and
3904	* PERF_COUNT_SW_BPF_OUTPUT as config.
3905	*
3906	* The flags are used to indicate the index in map for which
3907	* the value must be put, masked with BPF_F_INDEX_MASK.
3908	* Alternatively, flags can be set to BPF_F_CURRENT_CPU
3909	* to indicate that the index of the current CPU core should be
3910	* used.
3911	*
3912	* The value to write, of size, is passed through eBPF stack and
3913	* pointed by data.
3914	*
3915	* ctx is a pointer to in-kernel struct xdp_buff.
3916	*
3917	* This helper is similar to bpf_perf_eventoutput\ () but
3918	* restricted to raw_tracepoint bpf programs.
3919	* Return
3920	* 0 on success, or a negative error in case of failure.
3921	*
3922	* u64 bpf_get_netns_cookie(void *ctx)
3923	* Description
3924	* Retrieve the cookie (generated by the kernel) of the network
3925	* namespace the input ctx is associated with. The network
3926	* namespace cookie remains stable for its lifetime and provides
3927	* a global identifier that can be assumed unique. If ctx is
3928	* NULL, then the helper returns the cookie for the initial
3929	* network namespace. The cookie itself is very similar to that
3930	* of bpf_get_socket_cookie\ () helper, but for network
3931	* namespaces instead of sockets.
3932	* Return
3933	* A 8-byte long opaque number.
3934	*
3935	* u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
3936	* Description
3937	* Return id of cgroup v2 that is ancestor of the cgroup associated
3938	* with the current task at the ancestor_level. The root cgroup
3939	* is at ancestor_level zero and each step down the hierarchy
3940	* increments the level. If ancestor_level == level of cgroup
3941	* associated with the current task, then return value will be the
3942	* same as that of bpf_get_current_cgroup_id\ ().
3943	*
3944	* The helper is useful to implement policies based on cgroups
3945	* that are upper in hierarchy than immediate cgroup associated
3946	* with the current task.
3947	*
3948	* The format of returned id and helper limitations are same as in
3949	* bpf_get_current_cgroup_id\ ().
3950	* Return
3951	* The id is returned or 0 in case the id could not be retrieved.
3952	*
3953	* long bpf_sk_assign(struct sk_buff skb, void sk, u64 flags)
3954	* Description
3955	* Helper is overloaded depending on BPF program type. This
3956	* description applies to BPF_PROG_TYPE_SCHED_CLS and
3957	* BPF_PROG_TYPE_SCHED_ACT programs.
3958	*
3959	* Assign the sk to the skb. When combined with appropriate
3960	* routing configuration to receive the packet towards the socket,
3961	* will cause skb to be delivered to the specified socket.
3962	* Subsequent redirection of skb via bpf_redirect\ (),
3963	* bpf_clone_redirect\ () or other methods outside of BPF may
3964	* interfere with successful delivery to the socket.
3965	*
3966	* This operation is only valid from TC ingress path.
3967	*
3968	* The flags argument must be zero.
3969	* Return
3970	* 0 on success, or a negative error in case of failure:
3971	*
3972	* -EINVAL if specified flags are not supported.
3973	*
3974	* -ENOENT if the socket is unavailable for assignment.
3975	*
3976	* -ENETUNREACH if the socket is unreachable (wrong netns).
3977	*
3978	* -EOPNOTSUPP if the operation is not supported, for example
3979	* a call from outside of TC ingress.
3980	*
3981	* -ESOCKTNOSUPPORT if the socket type is not supported
3982	* (reuseport).
3983	*
3984	* long bpf_sk_assign(struct bpf_sk_lookup ctx, struct bpf_sock sk, u64 flags)
3985	* Description
3986	* Helper is overloaded depending on BPF program type. This
3987	* description applies to BPF_PROG_TYPE_SK_LOOKUP programs.
3988	*
3989	* Select the sk as a result of a socket lookup.
3990	*
3991	* For the operation to succeed passed socket must be compatible
3992	* with the packet description provided by the ctx object.
3993	*
3994	* L4 protocol (IPPROTO_TCP or IPPROTO_UDP) must
3995	* be an exact match. While IP family (AF_INET or
3996	* AF_INET6) must be compatible, that is IPv6 sockets
3997	* that are not v6-only can be selected for IPv4 packets.
3998	*
3999	* Only TCP listeners and UDP unconnected sockets can be
4000	* selected. sk can also be NULL to reset any previous
4001	* selection.
4002	*
4003	* flags argument can combination of following values:
4004	*
4005	* * BPF_SK_LOOKUP_F_REPLACE to override the previous
4006	* socket selection, potentially done by a BPF program
4007	* that ran before us.
4008	*
4009	* * BPF_SK_LOOKUP_F_NO_REUSEPORT to skip
4010	* load-balancing within reuseport group for the socket
4011	* being selected.
4012	*
4013	* On success ctx->sk will point to the selected socket.
4014	*
4015	* Return
4016	* 0 on success, or a negative errno in case of failure.
4017	*
4018	* * -EAFNOSUPPORT if socket family (sk->family) is
4019	* not compatible with packet family (ctx->family).
4020	*
4021	* * -EEXIST if socket has been already selected,
4022	* potentially by another program, and
4023	* BPF_SK_LOOKUP_F_REPLACE flag was not specified.
4024	*
4025	* * -EINVAL if unsupported flags were specified.
4026	*
4027	* * -EPROTOTYPE if socket L4 protocol
4028	* (sk->protocol) doesn't match packet protocol
4029	* (ctx->protocol).
4030	*
4031	* * -ESOCKTNOSUPPORT if socket is not in allowed
4032	* state (TCP listening or UDP unconnected).
4033	*
4034	* u64 bpf_ktime_get_boot_ns(void)
4035	* Description
4036	* Return the time elapsed since system boot, in nanoseconds.
4037	* Does include the time the system was suspended.
4038	* See: clock_gettime\ (CLOCK_BOOTTIME)
4039	* Return
4040	* Current ktime.
4041	*
4042	* long bpf_seq_printf(struct seq_file m, const char fmt, u32 fmt_size, const void *data, u32 data_len)
4043	* Description
4044	* bpf_seq_printf\ () uses seq_file seq_printf\ () to print
4045	* out the format string.
4046	* The m represents the seq_file. The fmt and fmt_size are for
4047	* the format string itself. The data and data_len are format string
4048	* arguments. The data are a u64 array and corresponding format string
4049	* values are stored in the array. For strings and pointers where pointees
4050	* are accessed, only the pointer values are stored in the data array.
4051	* The data_len is the size of data in bytes.
4052	*
4053	* Formats %s, %p{i,I}{4,6} requires to read kernel memory.
4054	* Reading kernel memory may fail due to either invalid address or
4055	* valid address but requiring a major memory fault. If reading kernel memory
4056	* fails, the string for %s will be an empty string, and the ip
4057	* address for %p{i,I}{4,6} will be 0. Not returning error to
4058	* bpf program is consistent with what bpf_trace_printk\ () does for now.
4059	* Return
4060	* 0 on success, or a negative error in case of failure:
4061	*
4062	* -EBUSY if per-CPU memory copy buffer is busy, can try again
4063	* by returning 1 from bpf program.
4064	*
4065	* -EINVAL if arguments are invalid, or if fmt is invalid/unsupported.
4066	*
4067	* -E2BIG if fmt contains too many format specifiers.
4068	*
4069	* -EOVERFLOW if an overflow happened: The same object will be tried again.
4070	*
4071	* long bpf_seq_write(struct seq_file m, const void data, u32 len)
4072	* Description
4073	* bpf_seq_write\ () uses seq_file seq_write\ () to write the data.
4074	* The m represents the seq_file. The data and len represent the
4075	* data to write in bytes.
4076	* Return
4077	* 0 on success, or a negative error in case of failure:
4078	*
4079	* -EOVERFLOW if an overflow happened: The same object will be tried again.
4080	*
4081	* u64 bpf_sk_cgroup_id(void *sk)
4082	* Description
4083	* Return the cgroup v2 id of the socket sk.
4084	*
4085	* sk must be a non-NULL pointer to a socket, e.g. one
4086	* returned from bpf_sk_lookup_xxx\ (),
4087	* bpf_sk_fullsock\ (), etc. The format of returned id is
4088	* same as in bpf_skb_cgroup_id\ ().
4089	*
4090	* This helper is available only if the kernel was compiled with
4091	* the CONFIG_SOCK_CGROUP_DATA configuration option.
4092	* Return
4093	* The id is returned or 0 in case the id could not be retrieved.
4094	*
4095	* u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4096	* Description
4097	* Return id of cgroup v2 that is ancestor of cgroup associated
4098	* with the sk at the ancestor_level. The root cgroup is at
4099	* ancestor_level zero and each step down the hierarchy
4100	* increments the level. If ancestor_level == level of cgroup
4101	* associated with sk, then return value will be same as that
4102	* of bpf_sk_cgroup_id\ ().
4103	*
4104	* The helper is useful to implement policies based on cgroups
4105	* that are upper in hierarchy than immediate cgroup associated
4106	* with sk.
4107	*
4108	* The format of returned id and helper limitations are same as in
4109	* bpf_sk_cgroup_id\ ().
4110	* Return
4111	* The id is returned or 0 in case the id could not be retrieved.
4112	*
4113	* long bpf_ringbuf_output(void ringbuf, void data, u64 size, u64 flags)
4114	* Description
4115	* Copy size bytes from data into a ring buffer ringbuf.
4116	* If BPF_RB_NO_WAKEUP is specified in flags, no notification
4117	* of new data availability is sent.
4118	* If BPF_RB_FORCE_WAKEUP is specified in flags, notification
4119	* of new data availability is sent unconditionally.
4120	* If 0 is specified in flags, an adaptive notification
4121	* of new data availability is sent.
4122	*
4123	* An adaptive notification is a notification sent whenever the user-space
4124	* process has caught up and consumed all available payloads. In case the user-space
4125	* process is still processing a previous payload, then no notification is needed
4126	* as it will process the newly added payload automatically.
4127	* Return
4128	* 0 on success, or a negative error in case of failure.
4129	*
4130	* void bpf_ringbuf_reserve(void ringbuf, u64 size, u64 flags)
4131	* Description
4132	* Reserve size bytes of payload in a ring buffer ringbuf.
4133	* flags must be 0.
4134	* Return
4135	* Valid pointer with size bytes of memory available; NULL,
4136	* otherwise.
4137	*
4138	* void bpf_ringbuf_submit(void *data, u64 flags)
4139	* Description
4140	* Submit reserved ring buffer sample, pointed to by data.
4141	* If BPF_RB_NO_WAKEUP is specified in flags, no notification
4142	* of new data availability is sent.
4143	* If BPF_RB_FORCE_WAKEUP is specified in flags, notification
4144	* of new data availability is sent unconditionally.
4145	* If 0 is specified in flags, an adaptive notification
4146	* of new data availability is sent.
4147	*
4148	* See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4149	* Return
4150	* Nothing. Always succeeds.
4151	*
4152	* void bpf_ringbuf_discard(void *data, u64 flags)
4153	* Description
4154	* Discard reserved ring buffer sample, pointed to by data.
4155	* If BPF_RB_NO_WAKEUP is specified in flags, no notification
4156	* of new data availability is sent.
4157	* If BPF_RB_FORCE_WAKEUP is specified in flags, notification
4158	* of new data availability is sent unconditionally.
4159	* If 0 is specified in flags, an adaptive notification
4160	* of new data availability is sent.
4161	*
4162	* See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4163	* Return
4164	* Nothing. Always succeeds.
4165	*
4166	* u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4167	* Description
4168	* Query various characteristics of provided ring buffer. What
4169	* exactly is queries is determined by flags:
4170	*
4171	* * BPF_RB_AVAIL_DATA: Amount of data not yet consumed.
4172	* * BPF_RB_RING_SIZE: The size of ring buffer.
4173	* * BPF_RB_CONS_POS: Consumer position (can wrap around).
4174	* * BPF_RB_PROD_POS: Producer(s) position (can wrap around).
4175	*
4176	* Data returned is just a momentary snapshot of actual values
4177	* and could be inaccurate, so this facility should be used to
4178	* power heuristics and for reporting, not to make 100% correct
4179	* calculation.
4180	* Return
4181	* Requested value, or 0, if flags are not recognized.
4182	*
4183	* long bpf_csum_level(struct sk_buff *skb, u64 level)
4184	* Description
4185	* Change the skbs checksum level by one layer up or down, or
4186	* reset it entirely to none in order to have the stack perform
4187	* checksum validation. The level is applicable to the following
4188	* protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4189	* \| ETH \| IP \| UDP \| GUE \| IP \| TCP \| into \| ETH \| IP \| TCP \|
4190	* through bpf_skb_adjust_room\ () helper with passing in
4191	* BPF_F_ADJ_ROOM_NO_CSUM_RESET flag would require one call
4192	* to bpf_csum_level\ () with BPF_CSUM_LEVEL_DEC since
4193	* the UDP header is removed. Similarly, an encap of the latter
4194	* into the former could be accompanied by a helper call to
4195	* bpf_csum_level\ () with BPF_CSUM_LEVEL_INC if the
4196	* skb is still intended to be processed in higher layers of the
4197	* stack instead of just egressing at tc.
4198	*
4199	* There are three supported level settings at this time:
4200	*
4201	* * BPF_CSUM_LEVEL_INC: Increases skb->csum_level for skbs
4202	* with CHECKSUM_UNNECESSARY.
4203	* * BPF_CSUM_LEVEL_DEC: Decreases skb->csum_level for skbs
4204	* with CHECKSUM_UNNECESSARY.
4205	* * BPF_CSUM_LEVEL_RESET: Resets skb->csum_level to 0 and
4206	* sets CHECKSUM_NONE to force checksum validation by the stack.
4207	* * BPF_CSUM_LEVEL_QUERY: No-op, returns the current
4208	* skb->csum_level.
4209	* Return
4210	* 0 on success, or a negative error in case of failure. In the
4211	* case of BPF_CSUM_LEVEL_QUERY, the current skb->csum_level
4212	* is returned or the error code -EACCES in case the skb is not
4213	* subject to CHECKSUM_UNNECESSARY.
4214	*
4215	* struct tcp6_sock bpf_skc_to_tcp6_sock(void sk)
4216	* Description
4217	* Dynamically cast a sk pointer to a tcp6_sock pointer.
4218	* Return
4219	* sk if casting is valid, or NULL otherwise.
4220	*
4221	* struct tcp_sock bpf_skc_to_tcp_sock(void sk)
4222	* Description
4223	* Dynamically cast a sk pointer to a tcp_sock pointer.
4224	* Return
4225	* sk if casting is valid, or NULL otherwise.
4226	*
4227	* struct tcp_timewait_sock bpf_skc_to_tcp_timewait_sock(void sk)
4228	* Description
4229	* Dynamically cast a sk pointer to a tcp_timewait_sock pointer.
4230	* Return
4231	* sk if casting is valid, or NULL otherwise.
4232	*
4233	* struct tcp_request_sock bpf_skc_to_tcp_request_sock(void sk)
4234	* Description
4235	* Dynamically cast a sk pointer to a tcp_request_sock pointer.
4236	* Return
4237	* sk if casting is valid, or NULL otherwise.
4238	*
4239	* struct udp6_sock bpf_skc_to_udp6_sock(void sk)
4240	* Description
4241	* Dynamically cast a sk pointer to a udp6_sock pointer.
4242	* Return
4243	* sk if casting is valid, or NULL otherwise.
4244	*
4245	* long bpf_get_task_stack(struct task_struct task, void buf, u32 size, u64 flags)
4246	* Description
4247	* Return a user or a kernel stack in bpf program provided buffer.
4248	* Note: the user stack will only be populated if the task is
4249	* the current task; all other tasks will return -EOPNOTSUPP.
4250	* To achieve this, the helper needs task, which is a valid
4251	* pointer to struct task_struct. To store the stacktrace, the
4252	* bpf program provides buf with a nonnegative size.
4253	*
4254	* The last argument, flags, holds the number of stack frames to
4255	* skip (from 0 to 255), masked with
4256	* BPF_F_SKIP_FIELD_MASK. The next bits can be used to set
4257	* the following flags:
4258	*
4259	* BPF_F_USER_STACK
4260	* Collect a user space stack instead of a kernel stack.
4261	* The task must be the current task.
4262	* BPF_F_USER_BUILD_ID
4263	* Collect buildid+offset instead of ips for user stack,
4264	* only valid if BPF_F_USER_STACK is also specified.
4265	*
4266	* bpf_get_task_stack\ () can collect up to
4267	* PERF_MAX_STACK_DEPTH both kernel and user frames, subject
4268	* to sufficient large buffer size. Note that
4269	* this limit can be controlled with the sysctl program, and
4270	* that it should be manually increased in order to profile long
4271	* user stacks (such as stacks for Java programs). To do so, use:
4272	*
4273	* ::
4274	*
4275	* # sysctl kernel.perf_event_max_stack=<new value>
4276	* Return
4277	* The non-negative copied buf length equal to or less than
4278	* size on success, or a negative error in case of failure.
4279	*
4280	* long bpf_load_hdr_opt(struct bpf_sock_ops skops, void searchby_res, u32 len, u64 flags)
4281	* Description
4282	* Load header option. Support reading a particular TCP header
4283	* option for bpf program (BPF_PROG_TYPE_SOCK_OPS).
4284	*
4285	* If flags is 0, it will search the option from the
4286	* skops\ ->skb_data. The comment in struct bpf_sock_ops
4287	* has details on what skb_data contains under different
4288	* skops\ ->op.
4289	*
4290	* The first byte of the searchby_res specifies the
4291	* kind that it wants to search.
4292	*
4293	* If the searching kind is an experimental kind
4294	* (i.e. 253 or 254 according to RFC6994). It also
4295	* needs to specify the "magic" which is either
4296	* 2 bytes or 4 bytes. It then also needs to
4297	* specify the size of the magic by using
4298	* the 2nd byte which is "kind-length" of a TCP
4299	* header option and the "kind-length" also
4300	* includes the first 2 bytes "kind" and "kind-length"
4301	* itself as a normal TCP header option also does.
4302	*
4303	* For example, to search experimental kind 254 with
4304	* 2 byte magic 0xeB9F, the searchby_res should be
4305	* [ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4306	*
4307	* To search for the standard window scale option (3),
4308	* the searchby_res should be [ 3, 0, 0, .... 0 ].
4309	* Note, kind-length must be 0 for regular option.
4310	*
4311	* Searching for No-Op (0) and End-of-Option-List (1) are
4312	* not supported.
4313	*
4314	* len must be at least 2 bytes which is the minimal size
4315	* of a header option.
4316	*
4317	* Supported flags:
4318	*
4319	* * BPF_LOAD_HDR_OPT_TCP_SYN to search from the
4320	* saved_syn packet or the just-received syn packet.
4321	*
4322	* Return
4323	* > 0 when found, the header option is copied to searchby_res.
4324	* The return value is the total length copied. On failure, a
4325	* negative error code is returned:
4326	*
4327	* -EINVAL if a parameter is invalid.
4328	*
4329	* -ENOMSG if the option is not found.
4330	*
4331	* -ENOENT if no syn packet is available when
4332	* BPF_LOAD_HDR_OPT_TCP_SYN is used.
4333	*
4334	* -ENOSPC if there is not enough space. Only len number of
4335	* bytes are copied.
4336	*
4337	* -EFAULT on failure to parse the header options in the
4338	* packet.
4339	*
4340	* -EPERM if the helper cannot be used under the current
4341	* skops\ ->op.
4342	*
4343	* long bpf_store_hdr_opt(struct bpf_sock_ops skops, const void from, u32 len, u64 flags)
4344	* Description
4345	* Store header option. The data will be copied
4346	* from buffer from with length len to the TCP header.
4347	*
4348	* The buffer from should have the whole option that
4349	* includes the kind, kind-length, and the actual
4350	* option data. The len must be at least kind-length
4351	* long. The kind-length does not have to be 4 byte
4352	* aligned. The kernel will take care of the padding
4353	* and setting the 4 bytes aligned value to th->doff.
4354	*
4355	* This helper will check for duplicated option
4356	* by searching the same option in the outgoing skb.
4357	*
4358	* This helper can only be called during
4359	* BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
4360	*
4361	* Return
4362	* 0 on success, or negative error in case of failure:
4363	*
4364	* -EINVAL If param is invalid.
4365	*
4366	* -ENOSPC if there is not enough space in the header.
4367	* Nothing has been written
4368	*
4369	* -EEXIST if the option already exists.
4370	*
4371	* -EFAULT on failrue to parse the existing header options.
4372	*
4373	* -EPERM if the helper cannot be used under the current
4374	* skops\ ->op.
4375	*
4376	* long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4377	* Description
4378	* Reserve len bytes for the bpf header option. The
4379	* space will be used by bpf_store_hdr_opt\ () later in
4380	* BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
4381	*
4382	* If bpf_reserve_hdr_opt\ () is called multiple times,
4383	* the total number of bytes will be reserved.
4384	*
4385	* This helper can only be called during
4386	* BPF_SOCK_OPS_HDR_OPT_LEN_CB.
4387	*
4388	* Return
4389	* 0 on success, or negative error in case of failure:
4390	*
4391	* -EINVAL if a parameter is invalid.
4392	*
4393	* -ENOSPC if there is not enough space in the header.
4394	*
4395	* -EPERM if the helper cannot be used under the current
4396	* skops\ ->op.
4397	*
4398	* void bpf_inode_storage_get(struct bpf_map map, void inode, void value, u64 flags)
4399	* Description
4400	* Get a bpf_local_storage from an inode.
4401	*
4402	* Logically, it could be thought of as getting the value from
4403	* a map with inode as the key. From this
4404	* perspective, the usage is not much different from
4405	* bpf_map_lookup_elem\ (map, &\ inode) except this
4406	* helper enforces the key must be an inode and the map must also
4407	* be a BPF_MAP_TYPE_INODE_STORAGE.
4408	*
4409	* Underneath, the value is stored locally at inode instead of
4410	* the map. The map is used as the bpf-local-storage
4411	* "type". The bpf-local-storage "type" (i.e. the map) is
4412	* searched against all bpf_local_storage residing at inode.
4413	*
4414	* An optional flags (BPF_LOCAL_STORAGE_GET_F_CREATE) can be
4415	* used such that a new bpf_local_storage will be
4416	* created if one does not exist. value can be used
4417	* together with BPF_LOCAL_STORAGE_GET_F_CREATE to specify
4418	* the initial value of a bpf_local_storage. If value is
4419	* NULL, the new bpf_local_storage will be zero initialized.
4420	* Return
4421	* A bpf_local_storage pointer is returned on success.
4422	*
4423	* NULL if not found or there was an error in adding
4424	* a new bpf_local_storage.
4425	*
4426	* int bpf_inode_storage_delete(struct bpf_map map, void inode)
4427	* Description
4428	* Delete a bpf_local_storage from an inode.
4429	* Return
4430	* 0 on success.
4431	*
4432	* -ENOENT if the bpf_local_storage cannot be found.
4433	*
4434	* long bpf_d_path(struct path path, char buf, u32 sz)
4435	* Description
4436	* Return full path for given struct path object, which
4437	* needs to be the kernel BTF path object. The path is
4438	* returned in the provided buffer buf of size sz and
4439	* is zero terminated.
4440	*
4441	* Return
4442	* On success, the strictly positive length of the string,
4443	* including the trailing NUL character. On error, a negative
4444	* value.
4445	*
4446	* long bpf_copy_from_user(void dst, u32 size, const void user_ptr)
4447	* Description
4448	* Read size bytes from user space address user_ptr and store
4449	* the data in dst. This is a wrapper of copy_from_user\ ().
4450	* Return
4451	* 0 on success, or a negative error in case of failure.
4452	*
4453	* long bpf_snprintf_btf(char str, u32 str_size, struct btf_ptr ptr, u32 btf_ptr_size, u64 flags)
4454	* Description
4455	* Use BTF to store a string representation of ptr->ptr in str,
4456	* using ptr->type_id. This value should specify the type
4457	* that ptr->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4458	* can be used to look up vmlinux BTF type ids. Traversing the
4459	* data structure using BTF, the type information and values are
4460	* stored in the first str_size - 1 bytes of str. Safe copy of
4461	* the pointer data is carried out to avoid kernel crashes during
4462	* operation. Smaller types can use string space on the stack;
4463	* larger programs can use map data to store the string
4464	* representation.
4465	*
4466	* The string can be subsequently shared with userspace via
4467	* bpf_perf_event_output() or ring buffer interfaces.
4468	* bpf_trace_printk() is to be avoided as it places too small
4469	* a limit on string size to be useful.
4470	*
4471	* flags is a combination of
4472	*
4473	* BTF_F_COMPACT
4474	* no formatting around type information
4475	* BTF_F_NONAME
4476	* no struct/union member names/types
4477	* BTF_F_PTR_RAW
4478	* show raw (unobfuscated) pointer values;
4479	* equivalent to printk specifier %px.
4480	* BTF_F_ZERO
4481	* show zero-valued struct/union members; they
4482	* are not displayed by default
4483	*
4484	* Return
4485	* The number of bytes that were written (or would have been
4486	* written if output had to be truncated due to string size),
4487	* or a negative error in cases of failure.
4488	*
4489	* long bpf_seq_printf_btf(struct seq_file m, struct btf_ptr ptr, u32 ptr_size, u64 flags)
4490	* Description
4491	* Use BTF to write to seq_write a string representation of
4492	* ptr->ptr, using ptr->type_id as per bpf_snprintf_btf().
4493	* flags are identical to those used for bpf_snprintf_btf.
4494	* Return
4495	* 0 on success or a negative error in case of failure.
4496	*
4497	* u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4498	* Description
4499	* See bpf_get_cgroup_classid\ () for the main description.
4500	* This helper differs from bpf_get_cgroup_classid\ () in that
4501	* the cgroup v1 net_cls class is retrieved only from the skb's
4502	* associated socket instead of the current process.
4503	* Return
4504	* The id is returned or 0 in case the id could not be retrieved.
4505	*
4506	* long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4507	* Description
4508	* Redirect the packet to another net device of index ifindex
4509	* and fill in L2 addresses from neighboring subsystem. This helper
4510	* is somewhat similar to bpf_redirect\ (), except that it
4511	* populates L2 addresses as well, meaning, internally, the helper
4512	* relies on the neighbor lookup for the L2 address of the nexthop.
4513	*
4514	* The helper will perform a FIB lookup based on the skb's
4515	* networking header to get the address of the next hop, unless
4516	* this is supplied by the caller in the params argument. The
4517	* plen argument indicates the len of params and should be set
4518	* to 0 if params is NULL.
4519	*
4520	* The flags argument is reserved and must be 0. The helper is
4521	* currently only supported for tc BPF program types, and enabled
4522	* for IPv4 and IPv6 protocols.
4523	* Return
4524	* The helper returns TC_ACT_REDIRECT on success or
4525	* TC_ACT_SHOT on error.
4526	*
4527	* void bpf_per_cpu_ptr(const void percpu_ptr, u32 cpu)
4528	* Description
4529	* Take a pointer to a percpu ksym, percpu_ptr, and return a
4530	* pointer to the percpu kernel variable on cpu. A ksym is an
4531	* extern variable decorated with '__ksym'. For ksym, there is a
4532	* global var (either static or global) defined of the same name
4533	* in the kernel. The ksym is percpu if the global var is percpu.
4534	* The returned pointer points to the global percpu var on cpu.
4535	*
4536	* bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4537	* kernel, except that bpf_per_cpu_ptr() may return NULL. This
4538	* happens if cpu is larger than nr_cpu_ids. The caller of
4539	* bpf_per_cpu_ptr() must check the returned value.
4540	* Return
4541	* A pointer pointing to the kernel percpu variable on cpu, or
4542	* NULL, if cpu is invalid.
4543	*
4544	* void bpf_this_cpu_ptr(const void percpu_ptr)
4545	* Description
4546	* Take a pointer to a percpu ksym, percpu_ptr, and return a
4547	* pointer to the percpu kernel variable on this cpu. See the
4548	* description of 'ksym' in bpf_per_cpu_ptr\ ().
4549	*
4550	* bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4551	* the kernel. Different from bpf_per_cpu_ptr\ (), it would
4552	* never return NULL.
4553	* Return
4554	* A pointer pointing to the kernel percpu variable on this cpu.
4555	*
4556	* long bpf_redirect_peer(u32 ifindex, u64 flags)
4557	* Description
4558	* Redirect the packet to another net device of index ifindex.
4559	* This helper is somewhat similar to bpf_redirect\ (), except
4560	* that the redirection happens to the ifindex' peer device and
4561	* the netns switch takes place from ingress to ingress without
4562	* going through the CPU's backlog queue.
4563	*
4564	* The flags argument is reserved and must be 0. The helper is
4565	* currently only supported for tc BPF program types at the ingress
4566	* hook and for veth device types. The peer device must reside in a
4567	* different network namespace.
4568	* Return
4569	* The helper returns TC_ACT_REDIRECT on success or
4570	* TC_ACT_SHOT on error.
4571	*
4572	* void bpf_task_storage_get(struct bpf_map map, struct task_struct task, void value, u64 flags)
4573	* Description
4574	* Get a bpf_local_storage from the task.
4575	*
4576	* Logically, it could be thought of as getting the value from
4577	* a map with task as the key. From this
4578	* perspective, the usage is not much different from
4579	* bpf_map_lookup_elem\ (map, &\ task) except this
4580	* helper enforces the key must be an task_struct and the map must also
4581	* be a BPF_MAP_TYPE_TASK_STORAGE.
4582	*
4583	* Underneath, the value is stored locally at task instead of
4584	* the map. The map is used as the bpf-local-storage
4585	* "type". The bpf-local-storage "type" (i.e. the map) is
4586	* searched against all bpf_local_storage residing at task.
4587	*
4588	* An optional flags (BPF_LOCAL_STORAGE_GET_F_CREATE) can be
4589	* used such that a new bpf_local_storage will be
4590	* created if one does not exist. value can be used
4591	* together with BPF_LOCAL_STORAGE_GET_F_CREATE to specify
4592	* the initial value of a bpf_local_storage. If value is
4593	* NULL, the new bpf_local_storage will be zero initialized.
4594	* Return
4595	* A bpf_local_storage pointer is returned on success.
4596	*
4597	* NULL if not found or there was an error in adding
4598	* a new bpf_local_storage.
4599	*
4600	* long bpf_task_storage_delete(struct bpf_map map, struct task_struct task)
4601	* Description
4602	* Delete a bpf_local_storage from a task.
4603	* Return
4604	* 0 on success.
4605	*
4606	* -ENOENT if the bpf_local_storage cannot be found.
4607	*
4608	* struct task_struct *bpf_get_current_task_btf(void)
4609	* Description
4610	* Return a BTF pointer to the "current" task.
4611	* This pointer can also be used in helpers that accept an
4612	* ARG_PTR_TO_BTF_ID of type task_struct.
4613	* Return
4614	* Pointer to the current task.
4615	*
4616	* long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4617	* Description
4618	* Set or clear certain options on bprm:
4619	*
4620	* BPF_F_BPRM_SECUREEXEC Set the secureexec bit
4621	* which sets the AT_SECURE auxv for glibc. The bit
4622	* is cleared if the flag is not specified.
4623	* Return
4624	* -EINVAL if invalid flags are passed, zero otherwise.
4625	*
4626	* u64 bpf_ktime_get_coarse_ns(void)
4627	* Description
4628	* Return a coarse-grained version of the time elapsed since
4629	* system boot, in nanoseconds. Does not include time the system
4630	* was suspended.
4631	*
4632	* See: clock_gettime\ (CLOCK_MONOTONIC_COARSE)
4633	* Return
4634	* Current ktime.
4635	*
4636	* long bpf_ima_inode_hash(struct inode inode, void dst, u32 size)
4637	* Description
4638	* Returns the stored IMA hash of the inode (if it's avaialable).
4639	* If the hash is larger than size, then only size
4640	* bytes will be copied to dst
4641	* Return
4642	* The hash_algo is returned on success,
4643	* -EOPNOTSUP if IMA is disabled or -EINVAL if
4644	* invalid arguments are passed.
4645	*
4646	* struct socket bpf_sock_from_file(struct file file)
4647	* Description
4648	* If the given file represents a socket, returns the associated
4649	* socket.
4650	* Return
4651	* A pointer to a struct socket on success or NULL if the file is
4652	* not a socket.
4653	*
4654	* long bpf_check_mtu(void ctx, u32 ifindex, u32 mtu_len, s32 len_diff, u64 flags)
4655	* Description
4656	* Check packet size against exceeding MTU of net device (based
4657	* on ifindex). This helper will likely be used in combination
4658	* with helpers that adjust/change the packet size.
4659	*
4660	* The argument len_diff can be used for querying with a planned
4661	* size change. This allows to check MTU prior to changing packet
4662	* ctx. Providing an len_diff adjustment that is larger than the
4663	* actual packet size (resulting in negative packet size) will in
4664	* principle not exceed the MTU, why it is not considered a
4665	* failure. Other BPF-helpers are needed for performing the
4666	* planned size change, why the responsability for catch a negative
4667	* packet size belong in those helpers.
4668	*
4669	* Specifying ifindex zero means the MTU check is performed
4670	* against the current net device. This is practical if this isn't
4671	* used prior to redirect.
4672	*
4673	* On input mtu_len must be a valid pointer, else verifier will
4674	* reject BPF program. If the value mtu_len is initialized to
4675	* zero then the ctx packet size is use. When value mtu_len is
4676	* provided as input this specify the L3 length that the MTU check
4677	* is done against. Remember XDP and TC length operate at L2, but
4678	* this value is L3 as this correlate to MTU and IP-header tot_len
4679	* values which are L3 (similar behavior as bpf_fib_lookup).
4680	*
4681	* The Linux kernel route table can configure MTUs on a more
4682	* specific per route level, which is not provided by this helper.
4683	* For route level MTU checks use the bpf_fib_lookup\ ()
4684	* helper.
4685	*
4686	* ctx is either struct xdp_md for XDP programs or
4687	* struct sk_buff for tc cls_act programs.
4688	*
4689	* The flags argument can be a combination of one or more of the
4690	* following values:
4691	*
4692	* BPF_MTU_CHK_SEGS
4693	* This flag will only works for ctx struct sk_buff.
4694	* If packet context contains extra packet segment buffers
4695	* (often knows as GSO skb), then MTU check is harder to
4696	* check at this point, because in transmit path it is
4697	* possible for the skb packet to get re-segmented
4698	* (depending on net device features). This could still be
4699	* a MTU violation, so this flag enables performing MTU
4700	* check against segments, with a different violation
4701	* return code to tell it apart. Check cannot use len_diff.
4702	*
4703	* On return mtu_len pointer contains the MTU value of the net
4704	* device. Remember the net device configured MTU is the L3 size,
4705	* which is returned here and XDP and TC length operate at L2.
4706	* Helper take this into account for you, but remember when using
4707	* MTU value in your BPF-code.
4708	*
4709	* Return
4710	* * 0 on success, and populate MTU value in mtu_len pointer.
4711	*
4712	* * < 0 if any input argument is invalid (mtu_len not updated)
4713	*
4714	* MTU violations return positive values, but also populate MTU
4715	* value in mtu_len pointer, as this can be needed for
4716	* implementing PMTU handing:
4717	*
4718	* * BPF_MTU_CHK_RET_FRAG_NEEDED
4719	* * BPF_MTU_CHK_RET_SEGS_TOOBIG
4720	*
4721	* long bpf_for_each_map_elem(struct bpf_map map, void callback_fn, void *callback_ctx, u64 flags)
4722	* Description
4723	* For each element in map, call callback_fn function with
4724	* map, callback_ctx and other map-specific parameters.
4725	* The callback_fn should be a static function and
4726	* the callback_ctx should be a pointer to the stack.
4727	* The flags is used to control certain aspects of the helper.
4728	* Currently, the flags must be 0.
4729	*
4730	* The following are a list of supported map types and their
4731	* respective expected callback signatures:
4732	*
4733	* BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4734	* BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4735	* BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4736	*
4737	* long (\callback_fn)(struct bpf_map \map, const void \key, void \value, void \*ctx);
4738	*
4739	* For per_cpu maps, the map_value is the value on the cpu where the
4740	* bpf_prog is running.
4741	*
4742	* If callback_fn return 0, the helper will continue to the next
4743	* element. If return value is 1, the helper will skip the rest of
4744	* elements and return. Other return values are not used now.
4745	*
4746	* Return
4747	* The number of traversed map elements for success, -EINVAL for
4748	* invalid flags.
4749	*
4750	* long bpf_snprintf(char str, u32 str_size, const char fmt, u64 *data, u32 data_len)
4751	* Description
4752	* Outputs a string into the str buffer of size str_size
4753	* based on a format string stored in a read-only map pointed by
4754	* fmt.
4755	*
4756	* Each format specifier in fmt corresponds to one u64 element
4757	* in the data array. For strings and pointers where pointees
4758	* are accessed, only the pointer values are stored in the data
4759	* array. The data_len is the size of data in bytes.
4760	*
4761	* Formats %s and %p{i,I}{4,6} require to read kernel
4762	* memory. Reading kernel memory may fail due to either invalid
4763	* address or valid address but requiring a major memory fault. If
4764	* reading kernel memory fails, the string for %s will be an
4765	* empty string, and the ip address for %p{i,I}{4,6} will be 0.
4766	* Not returning error to bpf program is consistent with what
4767	* bpf_trace_printk\ () does for now.
4768	*
4769	* Return
4770	* The strictly positive length of the formatted string, including
4771	* the trailing zero character. If the return value is greater than
4772	* str_size, str contains a truncated string, guaranteed to
4773	* be zero-terminated except when str_size is 0.
4774	*
4775	* Or -EBUSY if the per-CPU memory copy buffer is busy.
4776	*
4777	* long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4778	* Description
4779	* Execute bpf syscall with given arguments.
4780	* Return
4781	* A syscall result.
4782	*
4783	* long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4784	* Description
4785	* Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4786	* Return
4787	* Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4788	*
4789	* long bpf_sys_close(u32 fd)
4790	* Description
4791	* Execute close syscall for given FD.
4792	* Return
4793	* A syscall result.
4794	*
4795	* long bpf_timer_init(struct bpf_timer timer, struct bpf_map map, u64 flags)
4796	* Description
4797	* Initialize the timer.
4798	* First 4 bits of flags specify clockid.
4799	* Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4800	* All other bits of flags are reserved.
4801	* The verifier will reject the program if timer is not from
4802	* the same map.
4803	* Return
4804	* 0 on success.
4805	* -EBUSY if timer is already initialized.
4806	* -EINVAL if invalid flags are passed.
4807	* -EPERM if timer is in a map that doesn't have any user references.
4808	* The user space should either hold a file descriptor to a map with timers
4809	* or pin such map in bpffs. When map is unpinned or file descriptor is
4810	* closed all timers in the map will be cancelled and freed.
4811	*
4812	* long bpf_timer_set_callback(struct bpf_timer timer, void callback_fn)
4813	* Description
4814	* Configure the timer to call callback_fn static function.
4815	* Return
4816	* 0 on success.
4817	* -EINVAL if timer was not initialized with bpf_timer_init() earlier.
4818	* -EPERM if timer is in a map that doesn't have any user references.
4819	* The user space should either hold a file descriptor to a map with timers
4820	* or pin such map in bpffs. When map is unpinned or file descriptor is
4821	* closed all timers in the map will be cancelled and freed.
4822	*
4823	* long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4824	* Description
4825	* Set timer expiration N nanoseconds from the current time. The
4826	* configured callback will be invoked in soft irq context on some cpu
4827	* and will not repeat unless another bpf_timer_start() is made.
4828	* In such case the next invocation can migrate to a different cpu.
4829	* Since struct bpf_timer is a field inside map element the map
4830	* owns the timer. The bpf_timer_set_callback() will increment refcnt
4831	* of BPF program to make sure that callback_fn code stays valid.
4832	* When user space reference to a map reaches zero all timers
4833	* in a map are cancelled and corresponding program's refcnts are
4834	* decremented. This is done to make sure that Ctrl-C of a user
4835	* process doesn't leave any timers running. If map is pinned in
4836	* bpffs the callback_fn can re-arm itself indefinitely.
4837	* bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4838	* cancel and free the timer in the given map element.
4839	* The map can contain timers that invoke callback_fn-s from different
4840	* programs. The same callback_fn can serve different timers from
4841	* different maps if key/value layout matches across maps.
4842	* Every bpf_timer_set_callback() can have different callback_fn.
4843	*
4844	* Return
4845	* 0 on success.
4846	* -EINVAL if timer was not initialized with bpf_timer_init() earlier
4847	* or invalid flags are passed.
4848	*
4849	* long bpf_timer_cancel(struct bpf_timer *timer)
4850	* Description
4851	* Cancel the timer and wait for callback_fn to finish if it was running.
4852	* Return
4853	* 0 if the timer was not active.
4854	* 1 if the timer was active.
4855	* -EINVAL if timer was not initialized with bpf_timer_init() earlier.
4856	* -EDEADLK if callback_fn tried to call bpf_timer_cancel() on its
4857	* own timer which would have led to a deadlock otherwise.
4858	*
4859	* u64 bpf_get_func_ip(void *ctx)
4860	* Description
4861	* Get address of the traced function (for tracing and kprobe programs).
4862	* Return
4863	* Address of the traced function.
4864	*
4865	* u64 bpf_get_attach_cookie(void *ctx)
4866	* Description
4867	* Get bpf_cookie value provided (optionally) during the program
4868	* attachment. It might be different for each individual
4869	* attachment, even if BPF program itself is the same.
4870	* Expects BPF program context ctx as a first argument.
4871	*
4872	* Supported for the following program types:
4873	* - kprobe/uprobe;
4874	* - tracepoint;
4875	* - perf_event.
4876	* Return
4877	* Value specified by user at BPF link creation/attachment time
4878	* or 0, if it was not specified.
4879	*
4880	* long bpf_task_pt_regs(struct task_struct *task)
4881	* Description
4882	* Get the struct pt_regs associated with task.
4883	* Return
4884	* A pointer to struct pt_regs.
4885	*/
4886	#define __BPF_FUNC_MAPPER(FN) \
4887	FN(unspec), \
4888	FN(map_lookup_elem), \
4889	FN(map_update_elem), \
4890	FN(map_delete_elem), \
4891	FN(probe_read), \
4892	FN(ktime_get_ns), \
4893	FN(trace_printk), \
4894	FN(get_prandom_u32), \
4895	FN(get_smp_processor_id), \
4896	FN(skb_store_bytes), \
4897	FN(l3_csum_replace), \
4898	FN(l4_csum_replace), \
4899	FN(tail_call), \
4900	FN(clone_redirect), \
4901	FN(get_current_pid_tgid), \
4902	FN(get_current_uid_gid), \
4903	FN(get_current_comm), \
4904	FN(get_cgroup_classid), \
4905	FN(skb_vlan_push), \
4906	FN(skb_vlan_pop), \
4907	FN(skb_get_tunnel_key), \
4908	FN(skb_set_tunnel_key), \
4909	FN(perf_event_read), \
4910	FN(redirect), \
4911	FN(get_route_realm), \
4912	FN(perf_event_output), \
4913	FN(skb_load_bytes), \
4914	FN(get_stackid), \
4915	FN(csum_diff), \
4916	FN(skb_get_tunnel_opt), \
4917	FN(skb_set_tunnel_opt), \
4918	FN(skb_change_proto), \
4919	FN(skb_change_type), \
4920	FN(skb_under_cgroup), \
4921	FN(get_hash_recalc), \
4922	FN(get_current_task), \
4923	FN(probe_write_user), \
4924	FN(current_task_under_cgroup), \
4925	FN(skb_change_tail), \
4926	FN(skb_pull_data), \
4927	FN(csum_update), \
4928	FN(set_hash_invalid), \
4929	FN(get_numa_node_id), \
4930	FN(skb_change_head), \
4931	FN(xdp_adjust_head), \
4932	FN(probe_read_str), \
4933	FN(get_socket_cookie), \
4934	FN(get_socket_uid), \
4935	FN(set_hash), \
4936	FN(setsockopt), \
4937	FN(skb_adjust_room), \
4938	FN(redirect_map), \
4939	FN(sk_redirect_map), \
4940	FN(sock_map_update), \
4941	FN(xdp_adjust_meta), \
4942	FN(perf_event_read_value), \
4943	FN(perf_prog_read_value), \
4944	FN(getsockopt), \
4945	FN(override_return), \
4946	FN(sock_ops_cb_flags_set), \
4947	FN(msg_redirect_map), \
4948	FN(msg_apply_bytes), \
4949	FN(msg_cork_bytes), \
4950	FN(msg_pull_data), \
4951	FN(bind), \
4952	FN(xdp_adjust_tail), \
4953	FN(skb_get_xfrm_state), \
4954	FN(get_stack), \
4955	FN(skb_load_bytes_relative), \
4956	FN(fib_lookup), \
4957	FN(sock_hash_update), \
4958	FN(msg_redirect_hash), \
4959	FN(sk_redirect_hash), \
4960	FN(lwt_push_encap), \
4961	FN(lwt_seg6_store_bytes), \
4962	FN(lwt_seg6_adjust_srh), \
4963	FN(lwt_seg6_action), \
4964	FN(rc_repeat), \
4965	FN(rc_keydown), \
4966	FN(skb_cgroup_id), \
4967	FN(get_current_cgroup_id), \
4968	FN(get_local_storage), \
4969	FN(sk_select_reuseport), \
4970	FN(skb_ancestor_cgroup_id), \
4971	FN(sk_lookup_tcp), \
4972	FN(sk_lookup_udp), \
4973	FN(sk_release), \
4974	FN(map_push_elem), \
4975	FN(map_pop_elem), \
4976	FN(map_peek_elem), \
4977	FN(msg_push_data), \
4978	FN(msg_pop_data), \
4979	FN(rc_pointer_rel), \
4980	FN(spin_lock), \
4981	FN(spin_unlock), \
4982	FN(sk_fullsock), \
4983	FN(tcp_sock), \
4984	FN(skb_ecn_set_ce), \
4985	FN(get_listener_sock), \
4986	FN(skc_lookup_tcp), \
4987	FN(tcp_check_syncookie), \
4988	FN(sysctl_get_name), \
4989	FN(sysctl_get_current_value), \
4990	FN(sysctl_get_new_value), \
4991	FN(sysctl_set_new_value), \
4992	FN(strtol), \
4993	FN(strtoul), \
4994	FN(sk_storage_get), \
4995	FN(sk_storage_delete), \
4996	FN(send_signal), \
4997	FN(tcp_gen_syncookie), \
4998	FN(skb_output), \
4999	FN(probe_read_user), \
5000	FN(probe_read_kernel), \
5001	FN(probe_read_user_str), \
5002	FN(probe_read_kernel_str), \
5003	FN(tcp_send_ack), \
5004	FN(send_signal_thread), \
5005	FN(jiffies64), \
5006	FN(read_branch_records), \
5007	FN(get_ns_current_pid_tgid), \
5008	FN(xdp_output), \
5009	FN(get_netns_cookie), \
5010	FN(get_current_ancestor_cgroup_id), \
5011	FN(sk_assign), \
5012	FN(ktime_get_boot_ns), \
5013	FN(seq_printf), \
5014	FN(seq_write), \
5015	FN(sk_cgroup_id), \
5016	FN(sk_ancestor_cgroup_id), \
5017	FN(ringbuf_output), \
5018	FN(ringbuf_reserve), \
5019	FN(ringbuf_submit), \
5020	FN(ringbuf_discard), \
5021	FN(ringbuf_query), \
5022	FN(csum_level), \
5023	FN(skc_to_tcp6_sock), \
5024	FN(skc_to_tcp_sock), \
5025	FN(skc_to_tcp_timewait_sock), \
5026	FN(skc_to_tcp_request_sock), \
5027	FN(skc_to_udp6_sock), \
5028	FN(get_task_stack), \
5029	FN(load_hdr_opt), \
5030	FN(store_hdr_opt), \
5031	FN(reserve_hdr_opt), \
5032	FN(inode_storage_get), \
5033	FN(inode_storage_delete), \
5034	FN(d_path), \
5035	FN(copy_from_user), \
5036	FN(snprintf_btf), \
5037	FN(seq_printf_btf), \
5038	FN(skb_cgroup_classid), \
5039	FN(redirect_neigh), \
5040	FN(per_cpu_ptr), \
5041	FN(this_cpu_ptr), \
5042	FN(redirect_peer), \
5043	FN(task_storage_get), \
5044	FN(task_storage_delete), \
5045	FN(get_current_task_btf), \
5046	FN(bprm_opts_set), \
5047	FN(ktime_get_coarse_ns), \
5048	FN(ima_inode_hash), \
5049	FN(sock_from_file), \
5050	FN(check_mtu), \
5051	FN(for_each_map_elem), \
5052	FN(snprintf), \
5053	FN(sys_bpf), \
5054	FN(btf_find_by_name_kind), \
5055	FN(sys_close), \
5056	FN(timer_init), \
5057	FN(timer_set_callback), \
5058	FN(timer_start), \
5059	FN(timer_cancel), \
5060	FN(get_func_ip), \
5061	FN(get_attach_cookie), \
5062	FN(task_pt_regs), \
5063	/* */
5064
5065	/ integer value in 'imm' field of BPF_CALL instruction selects which helper*
5066	* function eBPF program intends to call
5067	*/
5068	#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5069	enum bpf_func_id {
5070	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5071	__BPF_FUNC_MAX_ID,
5072	};
5073	#undef __BPF_ENUM_FN
5074
5075	/ All flags used by eBPF helper functions, placed here. /
5076
5077	/ BPF_FUNC_skb_store_bytes flags. /
5078	enum {
5079	BPF_F_RECOMPUTE_CSUM = (`1ULL` << `0`),
5080	BPF_F_INVALIDATE_HASH = (`1ULL` << `1`),
5081	};
5082
5083	/ BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.*
5084	* First 4 bits are for passing the header field size.
5085	*/
5086	enum {
5087	BPF_F_HDR_FIELD_MASK = `0xfULL`,
5088	};
5089
5090	/ BPF_FUNC_l4_csum_replace flags. /
5091	enum {
5092	BPF_F_PSEUDO_HDR = (`1ULL` << `4`),
5093	BPF_F_MARK_MANGLED_0 = (`1ULL` << `5`),
5094	BPF_F_MARK_ENFORCE = (`1ULL` << `6`),
5095	};
5096
5097	/ BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. /
5098	enum {
5099	BPF_F_INGRESS = (`1ULL` << `0`),
5100	};
5101
5102	/ BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. /
5103	enum {
5104	BPF_F_TUNINFO_IPV6 = (`1ULL` << `0`),
5105	};
5106
5107	/ flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. /
5108	enum {
5109	BPF_F_SKIP_FIELD_MASK = `0xffULL`,
5110	BPF_F_USER_STACK = (`1ULL` << `8`),
5111	/ flags used by BPF_FUNC_get_stackid only. /
5112	BPF_F_FAST_STACK_CMP = (`1ULL` << `9`),
5113	BPF_F_REUSE_STACKID = (`1ULL` << `10`),
5114	/ flags used by BPF_FUNC_get_stack only. /
5115	BPF_F_USER_BUILD_ID = (`1ULL` << `11`),
5116	};
5117
5118	/ BPF_FUNC_skb_set_tunnel_key flags. /
5119	enum {
5120	BPF_F_ZERO_CSUM_TX = (`1ULL` << `1`),
5121	BPF_F_DONT_FRAGMENT = (`1ULL` << `2`),
5122	BPF_F_SEQ_NUMBER = (`1ULL` << `3`),
5123	};
5124
5125	/ BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and*
5126	* BPF_FUNC_perf_event_read_value flags.
5127	*/
5128	enum {
5129	BPF_F_INDEX_MASK = `0xffffffffULL`,
5130	BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK,
5131	/ BPF_FUNC_perf_event_output for sk_buff input context. /
5132	BPF_F_CTXLEN_MASK = (`0xfffffULL` << `32`),
5133	};
5134
5135	/ Current network namespace /
5136	enum {
5137	BPF_F_CURRENT_NETNS = (-`1L`),
5138	};
5139
5140	/ BPF_FUNC_csum_level level values. /
5141	enum {
5142	BPF_CSUM_LEVEL_QUERY,
5143	BPF_CSUM_LEVEL_INC,
5144	BPF_CSUM_LEVEL_DEC,
5145	BPF_CSUM_LEVEL_RESET,
5146	};
5147
5148	/ BPF_FUNC_skb_adjust_room flags. /
5149	enum {
5150	BPF_F_ADJ_ROOM_FIXED_GSO = (`1ULL` << `0`),
5151	BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 = (`1ULL` << `1`),
5152	BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 = (`1ULL` << `2`),
5153	BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (`1ULL` << `3`),
5154	BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (`1ULL` << `4`),
5155	BPF_F_ADJ_ROOM_NO_CSUM_RESET = (`1ULL` << `5`),
5156	BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (`1ULL` << `6`),
5157	};
5158
5159	enum {
5160	BPF_ADJ_ROOM_ENCAP_L2_MASK = `0xff`,
5161	BPF_ADJ_ROOM_ENCAP_L2_SHIFT = `56`,
5162	};
5163
5164	#define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \
5165	BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5166	<< BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5167
5168	/ BPF_FUNC_sysctl_get_name flags. /
5169	enum {
5170	BPF_F_SYSCTL_BASE_NAME = (`1ULL` << `0`),
5171	};
5172
5173	/ BPF_FUNC_<kernel_obj>_storage_get flags /
5174	enum {
5175	BPF_LOCAL_STORAGE_GET_F_CREATE = (`1ULL` << `0`),
5176	/ BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility*
5177	* and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5178	*/
5179	BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE,
5180	};
5181
5182	/ BPF_FUNC_read_branch_records flags. /
5183	enum {
5184	BPF_F_GET_BRANCH_RECORDS_SIZE = (`1ULL` << `0`),
5185	};
5186
5187	/ BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and*
5188	* BPF_FUNC_bpf_ringbuf_output flags.
5189	*/
5190	enum {
5191	BPF_RB_NO_WAKEUP = (`1ULL` << `0`),
5192	BPF_RB_FORCE_WAKEUP = (`1ULL` << `1`),
5193	};
5194
5195	/ BPF_FUNC_bpf_ringbuf_query flags /
5196	enum {
5197	BPF_RB_AVAIL_DATA = `0`,
5198	BPF_RB_RING_SIZE = `1`,
5199	BPF_RB_CONS_POS = `2`,
5200	BPF_RB_PROD_POS = `3`,
5201	};
5202
5203	/ BPF ring buffer constants /
5204	enum {
5205	BPF_RINGBUF_BUSY_BIT = (`1U` << `31`),
5206	BPF_RINGBUF_DISCARD_BIT = (`1U` << `30`),
5207	BPF_RINGBUF_HDR_SZ = `8`,
5208	};
5209
5210	/ BPF_FUNC_sk_assign flags in bpf_sk_lookup context. /
5211	enum {
5212	BPF_SK_LOOKUP_F_REPLACE = (`1ULL` << `0`),
5213	BPF_SK_LOOKUP_F_NO_REUSEPORT = (`1ULL` << `1`),
5214	};
5215
5216	/ Mode for BPF_FUNC_skb_adjust_room helper. /
5217	enum bpf_adj_room_mode {
5218	BPF_ADJ_ROOM_NET,
5219	BPF_ADJ_ROOM_MAC,
5220	};
5221
5222	/ Mode for BPF_FUNC_skb_load_bytes_relative helper. /
5223	enum bpf_hdr_start_off {
5224	BPF_HDR_START_MAC,
5225	BPF_HDR_START_NET,
5226	};
5227
5228	/ Encapsulation type for BPF_FUNC_lwt_push_encap helper. /
5229	enum bpf_lwt_encap_mode {
5230	BPF_LWT_ENCAP_SEG6,
5231	BPF_LWT_ENCAP_SEG6_INLINE,
5232	BPF_LWT_ENCAP_IP,
5233	};
5234
5235	/ Flags for bpf_bprm_opts_set helper /
5236	enum {
5237	BPF_F_BPRM_SECUREEXEC = (`1ULL` << `0`),
5238	};
5239
5240	/ Flags for bpf_redirect_map helper /
5241	enum {
5242	BPF_F_BROADCAST = (`1ULL` << `3`),
5243	BPF_F_EXCLUDE_INGRESS = (`1ULL` << `4`),
5244	};
5245
5246	#define __bpf_md_ptr(type, name) \
5247	union { \
5248	type name; \
5249	__u64 :64; \
5250	} __attribute__((aligned(8)))
5251
5252	/ user accessible mirror of in-kernel sk_buff.*
5253	* new fields can only be added to the end of this structure
5254	*/
5255	struct __sk_buff {
5256	__u32 len;
5257	__u32 pkt_type;
5258	__u32 mark;
5259	__u32 queue_mapping;
5260	__u32 protocol;
5261	__u32 vlan_present;
5262	__u32 vlan_tci;
5263	__u32 vlan_proto;
5264	__u32 priority;
5265	__u32 ingress_ifindex;
5266	__u32 ifindex;
5267	__u32 tc_index;
5268	__u32 cb[`5`];
5269	__u32 hash;
5270	__u32 tc_classid;
5271	__u32 data;
5272	__u32 data_end;
5273	__u32 napi_id;
5274
5275	/ Accessed by BPF_PROG_TYPE_sk_skb types from here to ... /
5276	__u32 family;
5277	__u32 remote_ip4; / Stored in network byte order /
5278	__u32 local_ip4; / Stored in network byte order /
5279	__u32 remote_ip6[`4`]; / Stored in network byte order /
5280	__u32 local_ip6[`4`]; / Stored in network byte order /
5281	__u32 remote_port; / Stored in network byte order /
5282	__u32 local_port; / stored in host byte order /
5283	/ ... here. /
5284
5285	__u32 data_meta;
5286	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5287	__u64 tstamp;
5288	__u32 wire_len;
5289	__u32 gso_segs;
5290	__bpf_md_ptr(struct bpf_sock *, sk);
5291	__u32 gso_size;
5292	};
5293
5294	struct bpf_tunnel_key {
5295	__u32 tunnel_id;
5296	union {
5297	__u32 remote_ipv4;
5298	__u32 remote_ipv6[`4`];
5299	};
5300	__u8 tunnel_tos;
5301	__u8 tunnel_ttl;
5302	__u16 tunnel_ext; / Padding, future use. /
5303	__u32 tunnel_label;
5304	};
5305
5306	/ user accessible mirror of in-kernel xfrm_state.*
5307	* new fields can only be added to the end of this structure
5308	*/
5309	struct bpf_xfrm_state {
5310	__u32 reqid;
5311	__u32 spi; / Stored in network byte order /
5312	__u16 family;
5313	__u16 ext; / Padding, future use. /
5314	union {
5315	__u32 remote_ipv4; / Stored in network byte order /
5316	__u32 remote_ipv6[`4`]; / Stored in network byte order /
5317	};
5318	};
5319
5320	/ Generic BPF return codes which all BPF program types may support.*
5321	* The values are binary compatible with their TC_ACT_* counter-part to
5322	* provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5323	* programs.
5324	*
5325	* XDP is handled seprately, see XDP_*.
5326	*/
5327	enum bpf_ret_code {
5328	BPF_OK = `0`,
5329	/ 1 reserved /
5330	BPF_DROP = `2`,
5331	/ 3-6 reserved /
5332	BPF_REDIRECT = `7`,
5333	/ >127 are reserved for prog type specific return codes.*
5334	*
5335	* BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5336	* BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5337	* changed and should be routed based on its new L3 header.
5338	* (This is an L3 redirect, as opposed to L2 redirect
5339	* represented by BPF_REDIRECT above).
5340	*/
5341	BPF_LWT_REROUTE = `128`,
5342	};
5343
5344	struct bpf_sock {
5345	__u32 bound_dev_if;
5346	__u32 family;
5347	__u32 type;
5348	__u32 protocol;
5349	__u32 mark;
5350	__u32 priority;
5351	/ IP address also allows 1 and 2 bytes access /
5352	__u32 src_ip4;
5353	__u32 src_ip6[`4`];
5354	__u32 src_port; / host byte order /
5355	__be16 dst_port; / network byte order /
5356	__u16 :`16`; / zero padding /
5357	__u32 dst_ip4;
5358	__u32 dst_ip6[`4`];
5359	__u32 state;
5360	__s32 rx_queue_mapping;
5361	};
5362
5363	struct bpf_tcp_sock {
5364	__u32 snd_cwnd; / Sending congestion window /
5365	__u32 srtt_us; / smoothed round trip time << 3 in usecs /
5366	__u32 rtt_min;
5367	__u32 snd_ssthresh; / Slow start size threshold /
5368	__u32 rcv_nxt; / What we want to receive next /
5369	__u32 snd_nxt; / Next sequence we send /
5370	__u32 snd_una; / First byte we want an ack for /
5371	__u32 mss_cache; / Cached effective mss, not including SACKS /
5372	__u32 ecn_flags; / ECN status bits. /
5373	__u32 rate_delivered; / saved rate sample: packets delivered /
5374	__u32 rate_interval_us; / saved rate sample: time elapsed /
5375	__u32 packets_out; / Packets which are "in flight" /
5376	__u32 retrans_out; / Retransmitted packets out /
5377	__u32 total_retrans; / Total retransmits for entire connection /
5378	__u32 segs_in; / RFC4898 tcpEStatsPerfSegsIn*
5379	* total number of segments in.
5380	*/
5381	__u32 data_segs_in; / RFC4898 tcpEStatsPerfDataSegsIn*
5382	* total number of data segments in.
5383	*/
5384	__u32 segs_out; / RFC4898 tcpEStatsPerfSegsOut*
5385	* The total number of segments sent.
5386	*/
5387	__u32 data_segs_out; / RFC4898 tcpEStatsPerfDataSegsOut*
5388	* total number of data segments sent.
5389	*/
5390	__u32 lost_out; / Lost packets /
5391	__u32 sacked_out; / SACK'd packets /
5392	__u64 bytes_received; / RFC4898 tcpEStatsAppHCThruOctetsReceived*
5393	* sum(delta(rcv_nxt)), or how many bytes
5394	* were acked.
5395	*/
5396	__u64 bytes_acked; / RFC4898 tcpEStatsAppHCThruOctetsAcked*
5397	* sum(delta(snd_una)), or how many bytes
5398	* were acked.
5399	*/
5400	__u32 dsack_dups; / RFC4898 tcpEStatsStackDSACKDups*
5401	* total number of DSACK blocks received
5402	*/
5403	__u32 delivered; / Total data packets delivered incl. rexmits /
5404	__u32 delivered_ce; / Like the above but only ECE marked packets /
5405	__u32 icsk_retransmits; / Number of unrecovered [RTO] timeouts /
5406	};
5407
5408	struct bpf_sock_tuple {
5409	union {
5410	struct {
5411	__be32 saddr;
5412	__be32 daddr;
5413	__be16 sport;
5414	__be16 dport;
5415	} ipv4;
5416	struct {
5417	__be32 saddr[`4`];
5418	__be32 daddr[`4`];
5419	__be16 sport;
5420	__be16 dport;
5421	} ipv6;
5422	};
5423	};
5424
5425	struct bpf_xdp_sock {
5426	__u32 queue_id;
5427	};
5428
5429	#define XDP_PACKET_HEADROOM 256
5430
5431	/ User return codes for XDP prog type.*
5432	* A valid XDP program must return one of these defined values. All other
5433	* return codes are reserved for future use. Unknown return codes will
5434	* result in packet drops and a warning via bpf_warn_invalid_xdp_action().
5435	*/
5436	enum xdp_action {
5437	XDP_ABORTED = `0`,
5438	XDP_DROP,
5439	XDP_PASS,
5440	XDP_TX,
5441	XDP_REDIRECT,
5442	};
5443
5444	/ user accessible metadata for XDP packet hook*
5445	* new fields must be added to the end of this structure
5446	*/
5447	struct xdp_md {
5448	__u32 data;
5449	__u32 data_end;
5450	__u32 data_meta;
5451	/ Below access go through struct xdp_rxq_info /
5452	__u32 ingress_ifindex; / rxq->dev->ifindex /
5453	__u32 rx_queue_index; / rxq->queue_index /
5454
5455	__u32 egress_ifindex; / txq->dev->ifindex /
5456	};
5457
5458	/ DEVMAP map-value layout*
5459	*
5460	* The struct data-layout of map-value is a configuration interface.
5461	* New members can only be added to the end of this structure.
5462	*/
5463	struct bpf_devmap_val {
5464	__u32 ifindex; / device index /
5465	union {
5466	int fd; / prog fd on map write /
5467	__u32 id; / prog id on map read /
5468	} bpf_prog;
5469	};
5470
5471	/ CPUMAP map-value layout*
5472	*
5473	* The struct data-layout of map-value is a configuration interface.
5474	* New members can only be added to the end of this structure.
5475	*/
5476	struct bpf_cpumap_val {
5477	__u32 qsize; / queue size to remote target CPU /
5478	union {
5479	int fd; / prog fd on map write /
5480	__u32 id; / prog id on map read /
5481	} bpf_prog;
5482	};
5483
5484	enum sk_action {
5485	SK_DROP = `0`,
5486	SK_PASS,
5487	};
5488
5489	/ user accessible metadata for SK_MSG packet hook, new fields must*
5490	* be added to the end of this structure
5491	*/
5492	struct sk_msg_md {
5493	__bpf_md_ptr(void *, data);
5494	__bpf_md_ptr(void *, data_end);
5495
5496	__u32 family;
5497	__u32 remote_ip4; / Stored in network byte order /
5498	__u32 local_ip4; / Stored in network byte order /
5499	__u32 remote_ip6[`4`]; / Stored in network byte order /
5500	__u32 local_ip6[`4`]; / Stored in network byte order /
5501	__u32 remote_port; / Stored in network byte order /
5502	__u32 local_port; / stored in host byte order /
5503	__u32 size; / Total size of sk_msg /
5504
5505	__bpf_md_ptr(struct bpf_sock , sk); /* current socket /
5506	};
5507
5508	struct sk_reuseport_md {
5509	/*
5510	* Start of directly accessible data. It begins from
5511	* the tcp/udp header.
5512	*/
5513	__bpf_md_ptr(void *, data);
5514	/ End of directly accessible data /
5515	__bpf_md_ptr(void *, data_end);
5516	/*
5517	* Total length of packet (starting from the tcp/udp header).
5518	* Note that the directly accessible bytes (data_end - data)
5519	* could be less than this "len". Those bytes could be
5520	* indirectly read by a helper "bpf_skb_load_bytes()".
5521	*/
5522	__u32 len;
5523	/*
5524	* Eth protocol in the mac header (network byte order). e.g.
5525	* ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
5526	*/
5527	__u32 eth_protocol;
5528	__u32 ip_protocol; / IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP /
5529	__u32 bind_inany; / Is sock bound to an INANY address? /
5530	__u32 hash; / A hash of the packet 4 tuples /
5531	/ When reuse->migrating_sk is NULL, it is selecting a sk for the*
5532	* new incoming connection request (e.g. selecting a listen sk for
5533	* the received SYN in the TCP case). reuse->sk is one of the sk
5534	* in the reuseport group. The bpf prog can use reuse->sk to learn
5535	* the local listening ip/port without looking into the skb.
5536	*
5537	* When reuse->migrating_sk is not NULL, reuse->sk is closed and
5538	* reuse->migrating_sk is the socket that needs to be migrated
5539	* to another listening socket. migrating_sk could be a fullsock
5540	* sk that is fully established or a reqsk that is in-the-middle
5541	* of 3-way handshake.
5542	*/
5543	__bpf_md_ptr(struct bpf_sock *, sk);
5544	__bpf_md_ptr(struct bpf_sock *, migrating_sk);
5545	};
5546
5547	#define BPF_TAG_SIZE 8
5548
5549	struct bpf_prog_info {
5550	__u32 type;
5551	__u32 id;
5552	__u8 tag[BPF_TAG_SIZE];
5553	__u32 jited_prog_len;
5554	__u32 xlated_prog_len;
5555	__aligned_u64 jited_prog_insns;
5556	__aligned_u64 xlated_prog_insns;
5557	__u64 load_time; / ns since boottime /
5558	__u32 created_by_uid;
5559	__u32 nr_map_ids;
5560	__aligned_u64 map_ids;
5561	char name[BPF_OBJ_NAME_LEN];
5562	__u32 ifindex;
5563	__u32 gpl_compatible:`1`;
5564	__u32 :`31`; / alignment pad /
5565	__u64 netns_dev;
5566	__u64 netns_ino;
5567	__u32 nr_jited_ksyms;
5568	__u32 nr_jited_func_lens;
5569	__aligned_u64 jited_ksyms;
5570	__aligned_u64 jited_func_lens;
5571	__u32 btf_id;
5572	__u32 func_info_rec_size;
5573	__aligned_u64 func_info;
5574	__u32 nr_func_info;
5575	__u32 nr_line_info;
5576	__aligned_u64 line_info;
5577	__aligned_u64 jited_line_info;
5578	__u32 nr_jited_line_info;
5579	__u32 line_info_rec_size;
5580	__u32 jited_line_info_rec_size;
5581	__u32 nr_prog_tags;
5582	__aligned_u64 prog_tags;
5583	__u64 run_time_ns;
5584	__u64 run_cnt;
5585	__u64 recursion_misses;
5586	} __attribute__((aligned(`8`)));
5587
5588	struct bpf_map_info {
5589	__u32 type;
5590	__u32 id;
5591	__u32 key_size;
5592	__u32 value_size;
5593	__u32 max_entries;
5594	__u32 map_flags;
5595	char name[BPF_OBJ_NAME_LEN];
5596	__u32 ifindex;
5597	__u32 btf_vmlinux_value_type_id;
5598	__u64 netns_dev;
5599	__u64 netns_ino;
5600	__u32 btf_id;
5601	__u32 btf_key_type_id;
5602	__u32 btf_value_type_id;
5603	} __attribute__((aligned(`8`)));
5604
5605	struct bpf_btf_info {
5606	__aligned_u64 btf;
5607	__u32 btf_size;
5608	__u32 id;
5609	__aligned_u64 name;
5610	__u32 name_len;
5611	__u32 kernel_btf;
5612	} __attribute__((aligned(`8`)));
5613
5614	struct bpf_link_info {
5615	__u32 type;
5616	__u32 id;
5617	__u32 prog_id;
5618	union {
5619	struct {
5620	__aligned_u64 tp_name; / in/out: tp_name buffer ptr /
5621	__u32 tp_name_len; / in/out: tp_name buffer len /
5622	} raw_tracepoint;
5623	struct {
5624	__u32 attach_type;
5625	__u32 target_obj_id; / prog_id for PROG_EXT, otherwise btf object id /
5626	__u32 target_btf_id; / BTF type id inside the object /
5627	} tracing;
5628	struct {
5629	__u64 cgroup_id;
5630	__u32 attach_type;
5631	} cgroup;
5632	struct {
5633	__aligned_u64 target_name; / in/out: target_name buffer ptr /
5634	__u32 target_name_len; / in/out: target_name buffer len /
5635	union {
5636	struct {
5637	__u32 map_id;
5638	} map;
5639	};
5640	} iter;
5641	struct {
5642	__u32 netns_ino;
5643	__u32 attach_type;
5644	} netns;
5645	struct {
5646	__u32 ifindex;
5647	} xdp;
5648	};
5649	} __attribute__((aligned(`8`)));
5650
5651	/ User bpf_sock_addr struct to access socket fields and sockaddr struct passed*
5652	* by user and intended to be used by socket (e.g. to bind to, depends on
5653	* attach type).
5654	*/
5655	struct bpf_sock_addr {
5656	__u32 user_family; / Allows 4-byte read, but no write. /
5657	__u32 user_ip4; / Allows 1,2,4-byte read and 4-byte write.*
5658	* Stored in network byte order.
5659	*/
5660	__u32 user_ip6[`4`]; / Allows 1,2,4,8-byte read and 4,8-byte write.*
5661	* Stored in network byte order.
5662	*/
5663	__u32 user_port; / Allows 1,2,4-byte read and 4-byte write.*
5664	* Stored in network byte order
5665	*/
5666	__u32 family; / Allows 4-byte read, but no write /
5667	__u32 type; / Allows 4-byte read, but no write /
5668	__u32 protocol; / Allows 4-byte read, but no write /
5669	__u32 msg_src_ip4; / Allows 1,2,4-byte read and 4-byte write.*
5670	* Stored in network byte order.
5671	*/
5672	__u32 msg_src_ip6[`4`]; / Allows 1,2,4,8-byte read and 4,8-byte write.*
5673	* Stored in network byte order.
5674	*/
5675	__bpf_md_ptr(struct bpf_sock *, sk);
5676	};
5677
5678	/ User bpf_sock_ops struct to access socket values and specify request ops*
5679	* and their replies.
5680	* Some of this fields are in network (bigendian) byte order and may need
5681	* to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
5682	* New fields can only be added at the end of this structure
5683	*/
5684	struct bpf_sock_ops {
5685	__u32 op;
5686	union {
5687	__u32 args[`4`]; / Optionally passed to bpf program /
5688	__u32 reply; / Returned by bpf program /
5689	__u32 replylong[`4`]; / Optionally returned by bpf prog /
5690	};
5691	__u32 family;
5692	__u32 remote_ip4; / Stored in network byte order /
5693	__u32 local_ip4; / Stored in network byte order /
5694	__u32 remote_ip6[`4`]; / Stored in network byte order /
5695	__u32 local_ip6[`4`]; / Stored in network byte order /
5696	__u32 remote_port; / Stored in network byte order /
5697	__u32 local_port; / stored in host byte order /
5698	__u32 is_fullsock; / Some TCP fields are only valid if*
5699	* there is a full socket. If not, the
5700	* fields read as zero.
5701	*/
5702	__u32 snd_cwnd;
5703	__u32 srtt_us; / Averaged RTT << 3 in usecs /
5704	__u32 bpf_sock_ops_cb_flags; / flags defined in uapi/linux/tcp.h /
5705	__u32 state;
5706	__u32 rtt_min;
5707	__u32 snd_ssthresh;
5708	__u32 rcv_nxt;
5709	__u32 snd_nxt;
5710	__u32 snd_una;
5711	__u32 mss_cache;
5712	__u32 ecn_flags;
5713	__u32 rate_delivered;
5714	__u32 rate_interval_us;
5715	__u32 packets_out;
5716	__u32 retrans_out;
5717	__u32 total_retrans;
5718	__u32 segs_in;
5719	__u32 data_segs_in;
5720	__u32 segs_out;
5721	__u32 data_segs_out;
5722	__u32 lost_out;
5723	__u32 sacked_out;
5724	__u32 sk_txhash;
5725	__u64 bytes_received;
5726	__u64 bytes_acked;
5727	__bpf_md_ptr(struct bpf_sock *, sk);
5728	/ [skb_data, skb_data_end) covers the whole TCP header.*
5729	*
5730	* BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
5731	* BPF_SOCK_OPS_HDR_OPT_LEN_CB: Not useful because the
5732	* header has not been written.
5733	* BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
5734	* been written so far.
5735	* BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: The SYNACK that concludes
5736	* the 3WHS.
5737	* BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
5738	* the 3WHS.
5739	*
5740	* bpf_load_hdr_opt() can also be used to read a particular option.
5741	*/
5742	__bpf_md_ptr(void *, skb_data);
5743	__bpf_md_ptr(void *, skb_data_end);
5744	__u32 skb_len; / The total length of a packet.*
5745	* It includes the header, options,
5746	* and payload.
5747	*/
5748	__u32 skb_tcp_flags; / tcp_flags of the header. It provides*
5749	* an easy way to check for tcp_flags
5750	* without parsing skb_data.
5751	*
5752	* In particular, the skb_tcp_flags
5753	* will still be available in
5754	* BPF_SOCK_OPS_HDR_OPT_LEN even though
5755	* the outgoing header has not
5756	* been written yet.
5757	*/
5758	};
5759
5760	/ Definitions for bpf_sock_ops_cb_flags /
5761	enum {
5762	BPF_SOCK_OPS_RTO_CB_FLAG = (`1`<<`0`),
5763	BPF_SOCK_OPS_RETRANS_CB_FLAG = (`1`<<`1`),
5764	BPF_SOCK_OPS_STATE_CB_FLAG = (`1`<<`2`),
5765	BPF_SOCK_OPS_RTT_CB_FLAG = (`1`<<`3`),
5766	/ Call bpf for all received TCP headers. The bpf prog will be*
5767	* called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5768	*
5769	* Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5770	* for the header option related helpers that will be useful
5771	* to the bpf programs.
5772	*
5773	* It could be used at the client/active side (i.e. connect() side)
5774	* when the server told it that the server was in syncookie
5775	* mode and required the active side to resend the bpf-written
5776	* options. The active side can keep writing the bpf-options until
5777	* it received a valid packet from the server side to confirm
5778	* the earlier packet (and options) has been received. The later
5779	* example patch is using it like this at the active side when the
5780	* server is in syncookie mode.
5781	*
5782	* The bpf prog will usually turn this off in the common cases.
5783	*/
5784	BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG = (`1`<<`4`),
5785	/ Call bpf when kernel has received a header option that*
5786	* the kernel cannot handle. The bpf prog will be called under
5787	* sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
5788	*
5789	* Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5790	* for the header option related helpers that will be useful
5791	* to the bpf programs.
5792	*/
5793	BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (`1`<<`5`),
5794	/ Call bpf when the kernel is writing header options for the*
5795	* outgoing packet. The bpf prog will first be called
5796	* to reserve space in a skb under
5797	* sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB. Then
5798	* the bpf prog will be called to write the header option(s)
5799	* under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5800	*
5801	* Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
5802	* and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
5803	* related helpers that will be useful to the bpf programs.
5804	*
5805	* The kernel gets its chance to reserve space and write
5806	* options first before the BPF program does.
5807	*/
5808	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (`1`<<`6`),
5809	/ Mask of all currently supported cb flags /
5810	BPF_SOCK_OPS_ALL_CB_FLAGS = `0x7F`,
5811	};
5812
5813	/ List of known BPF sock_ops operators.*
5814	* New entries can only be added at the end
5815	*/
5816	enum {
5817	BPF_SOCK_OPS_VOID,
5818	BPF_SOCK_OPS_TIMEOUT_INIT, / Should return SYN-RTO value to use or*
5819	* -1 if default value should be used
5820	*/
5821	BPF_SOCK_OPS_RWND_INIT, / Should return initial advertized*
5822	* window (in packets) or -1 if default
5823	* value should be used
5824	*/
5825	BPF_SOCK_OPS_TCP_CONNECT_CB, / Calls BPF program right before an*
5826	* active connection is initialized
5827	*/
5828	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, / Calls BPF program when an*
5829	* active connection is
5830	* established
5831	*/
5832	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, / Calls BPF program when a*
5833	* passive connection is
5834	* established
5835	*/
5836	BPF_SOCK_OPS_NEEDS_ECN, / If connection's congestion control*
5837	* needs ECN
5838	*/
5839	BPF_SOCK_OPS_BASE_RTT, / Get base RTT. The correct value is*
5840	* based on the path and may be
5841	* dependent on the congestion control
5842	* algorithm. In general it indicates
5843	* a congestion threshold. RTTs above
5844	* this indicate congestion
5845	*/
5846	BPF_SOCK_OPS_RTO_CB, / Called when an RTO has triggered.*
5847	* Arg1: value of icsk_retransmits
5848	* Arg2: value of icsk_rto
5849	* Arg3: whether RTO has expired
5850	*/
5851	BPF_SOCK_OPS_RETRANS_CB, / Called when skb is retransmitted.*
5852	* Arg1: sequence number of 1st byte
5853	* Arg2: # segments
5854	* Arg3: return value of
5855	* tcp_transmit_skb (0 => success)
5856	*/
5857	BPF_SOCK_OPS_STATE_CB, / Called when TCP changes state.*
5858	* Arg1: old_state
5859	* Arg2: new_state
5860	*/
5861	BPF_SOCK_OPS_TCP_LISTEN_CB, / Called on listen(2), right after*
5862	* socket transition to LISTEN state.
5863	*/
5864	BPF_SOCK_OPS_RTT_CB, / Called on every RTT.*
5865	*/
5866	BPF_SOCK_OPS_PARSE_HDR_OPT_CB, / Parse the header option.*
5867	* It will be called to handle
5868	* the packets received at
5869	* an already established
5870	* connection.
5871	*
5872	* sock_ops->skb_data:
5873	* Referring to the received skb.
5874	* It covers the TCP header only.
5875	*
5876	* bpf_load_hdr_opt() can also
5877	* be used to search for a
5878	* particular option.
5879	*/
5880	BPF_SOCK_OPS_HDR_OPT_LEN_CB, / Reserve space for writing the*
5881	* header option later in
5882	* BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5883	* Arg1: bool want_cookie. (in
5884	* writing SYNACK only)
5885	*
5886	* sock_ops->skb_data:
5887	* Not available because no header has
5888	* been written yet.
5889	*
5890	* sock_ops->skb_tcp_flags:
5891	* The tcp_flags of the
5892	* outgoing skb. (e.g. SYN, ACK, FIN).
5893	*
5894	* bpf_reserve_hdr_opt() should
5895	* be used to reserve space.
5896	*/
5897	BPF_SOCK_OPS_WRITE_HDR_OPT_CB, / Write the header options*
5898	* Arg1: bool want_cookie. (in
5899	* writing SYNACK only)
5900	*
5901	* sock_ops->skb_data:
5902	* Referring to the outgoing skb.
5903	* It covers the TCP header
5904	* that has already been written
5905	* by the kernel and the
5906	* earlier bpf-progs.
5907	*
5908	* sock_ops->skb_tcp_flags:
5909	* The tcp_flags of the outgoing
5910	* skb. (e.g. SYN, ACK, FIN).
5911	*
5912	* bpf_store_hdr_opt() should
5913	* be used to write the
5914	* option.
5915	*
5916	* bpf_load_hdr_opt() can also
5917	* be used to search for a
5918	* particular option that
5919	* has already been written
5920	* by the kernel or the
5921	* earlier bpf-progs.
5922	*/
5923	};
5924
5925	/ List of TCP states. There is a build check in net/ipv4/tcp.c to detect*
5926	* changes between the TCP and BPF versions. Ideally this should never happen.
5927	* If it does, we need to add code to convert them before calling
5928	* the BPF sock_ops function.
5929	*/
5930	enum {
5931	BPF_TCP_ESTABLISHED = `1`,
5932	BPF_TCP_SYN_SENT,
5933	BPF_TCP_SYN_RECV,
5934	BPF_TCP_FIN_WAIT1,
5935	BPF_TCP_FIN_WAIT2,
5936	BPF_TCP_TIME_WAIT,
5937	BPF_TCP_CLOSE,
5938	BPF_TCP_CLOSE_WAIT,
5939	BPF_TCP_LAST_ACK,
5940	BPF_TCP_LISTEN,
5941	BPF_TCP_CLOSING, / Now a valid state /
5942	BPF_TCP_NEW_SYN_RECV,
5943
5944	BPF_TCP_MAX_STATES / Leave at the end! /
5945	};
5946
5947	enum {
5948	TCP_BPF_IW = `1001`, / Set TCP initial congestion window /
5949	TCP_BPF_SNDCWND_CLAMP = `1002`, / Set sndcwnd_clamp /
5950	TCP_BPF_DELACK_MAX = `1003`, / Max delay ack in usecs /
5951	TCP_BPF_RTO_MIN = `1004`, / Min delay ack in usecs /
5952	/ Copy the SYN pkt to optval*
5953	*
5954	* BPF_PROG_TYPE_SOCK_OPS only. It is similar to the
5955	* bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
5956	* to only getting from the saved_syn. It can either get the
5957	* syn packet from:
5958	*
5959	* 1. the just-received SYN packet (only available when writing the
5960	* SYNACK). It will be useful when it is not necessary to
5961	* save the SYN packet for latter use. It is also the only way
5962	* to get the SYN during syncookie mode because the syn
5963	* packet cannot be saved during syncookie.
5964	*
5965	* OR
5966	*
5967	* 2. the earlier saved syn which was done by
5968	* bpf_setsockopt(TCP_SAVE_SYN).
5969	*
5970	* The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
5971	* SYN packet is obtained.
5972	*
5973	* If the bpf-prog does not need the IP[46] header, the
5974	* bpf-prog can avoid parsing the IP header by using
5975	* TCP_BPF_SYN. Otherwise, the bpf-prog can get both
5976	* IP[46] and TCP header by using TCP_BPF_SYN_IP.
5977	*
5978	* >0: Total number of bytes copied
5979	* -ENOSPC: Not enough space in optval. Only optlen number of
5980	* bytes is copied.
5981	* -ENOENT: The SYN skb is not available now and the earlier SYN pkt
5982	* is not saved by setsockopt(TCP_SAVE_SYN).
5983	*/
5984	TCP_BPF_SYN = `1005`, / Copy the TCP header /
5985	TCP_BPF_SYN_IP = `1006`, / Copy the IP[46] and TCP header /
5986	TCP_BPF_SYN_MAC = `1007`, / Copy the MAC, IP[46], and TCP header /
5987	};
5988
5989	enum {
5990	BPF_LOAD_HDR_OPT_TCP_SYN = (`1ULL` << `0`),
5991	};
5992
5993	/ args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and*
5994	* BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5995	*/
5996	enum {
5997	BPF_WRITE_HDR_TCP_CURRENT_MSS = `1`, / Kernel is finding the*
5998	* total option spaces
5999	* required for an established
6000	* sk in order to calculate the
6001	* MSS. No skb is actually
6002	* sent.
6003	*/
6004	BPF_WRITE_HDR_TCP_SYNACK_COOKIE = `2`, / Kernel is in syncookie mode*
6005	* when sending a SYN.
6006	*/
6007	};
6008
6009	struct bpf_perf_event_value {
6010	__u64 counter;
6011	__u64 enabled;
6012	__u64 running;
6013	};
6014
6015	enum {
6016	BPF_DEVCG_ACC_MKNOD = (`1ULL` << `0`),
6017	BPF_DEVCG_ACC_READ = (`1ULL` << `1`),
6018	BPF_DEVCG_ACC_WRITE = (`1ULL` << `2`),
6019	};
6020
6021	enum {
6022	BPF_DEVCG_DEV_BLOCK = (`1ULL` << `0`),
6023	BPF_DEVCG_DEV_CHAR = (`1ULL` << `1`),
6024	};
6025
6026	struct bpf_cgroup_dev_ctx {
6027	/ access_type encoded as (BPF_DEVCG_ACC_* << 16) \| BPF_DEVCG_DEV_* /
6028	__u32 access_type;
6029	__u32 major;
6030	__u32 minor;
6031	};
6032
6033	struct bpf_raw_tracepoint_args {
6034	__u64 args[`0`];
6035	};
6036
6037	/ DIRECT: Skip the FIB rules and go to FIB table associated with device*
6038	* OUTPUT: Do lookup from egress perspective; default is ingress
6039	*/
6040	enum {
6041	BPF_FIB_LOOKUP_DIRECT = (`1U` << `0`),
6042	BPF_FIB_LOOKUP_OUTPUT = (`1U` << `1`),
6043	};
6044
6045	enum {
6046	BPF_FIB_LKUP_RET_SUCCESS, / lookup successful /
6047	BPF_FIB_LKUP_RET_BLACKHOLE, / dest is blackholed; can be dropped /
6048	BPF_FIB_LKUP_RET_UNREACHABLE, / dest is unreachable; can be dropped /
6049	BPF_FIB_LKUP_RET_PROHIBIT, / dest not allowed; can be dropped /
6050	BPF_FIB_LKUP_RET_NOT_FWDED, / packet is not forwarded /
6051	BPF_FIB_LKUP_RET_FWD_DISABLED, / fwding is not enabled on ingress /
6052	BPF_FIB_LKUP_RET_UNSUPP_LWT, / fwd requires encapsulation /
6053	BPF_FIB_LKUP_RET_NO_NEIGH, / no neighbor entry for nh /
6054	BPF_FIB_LKUP_RET_FRAG_NEEDED, / fragmentation required to fwd /
6055	};
6056
6057	struct bpf_fib_lookup {
6058	/ input: network family for lookup (AF_INET, AF_INET6)*
6059	* output: network family of egress nexthop
6060	*/
6061	__u8 family;
6062
6063	/ set if lookup is to consider L4 data - e.g., FIB rules /
6064	__u8 l4_protocol;
6065	__be16 sport;
6066	__be16 dport;
6067
6068	union { / used for MTU check /
6069	/ input to lookup /
6070	__u16 tot_len; / L3 length from network hdr (iph->tot_len) /
6071
6072	/ output: MTU value /
6073	__u16 mtu_result;
6074	};
6075	/ input: L3 device index for lookup*
6076	* output: device index from FIB lookup
6077	*/
6078	__u32 ifindex;
6079
6080	union {
6081	/ inputs to lookup /
6082	__u8 tos; / AF_INET /
6083	__be32 flowinfo; / AF_INET6, flow_label + priority /
6084
6085	/ output: metric of fib result (IPv4/IPv6 only) /
6086	__u32 rt_metric;
6087	};
6088
6089	union {
6090	__be32 ipv4_src;
6091	__u32 ipv6_src[`4`]; / in6_addr; network order /
6092	};
6093
6094	/ input to bpf_fib_lookup, ipv{4,6}_dst is destination address in*
6095	* network header. output: bpf_fib_lookup sets to gateway address
6096	* if FIB lookup returns gateway route
6097	*/
6098	union {
6099	__be32 ipv4_dst;
6100	__u32 ipv6_dst[`4`]; / in6_addr; network order /
6101	};
6102
6103	/ output /
6104	__be16 h_vlan_proto;
6105	__be16 h_vlan_TCI;
6106	__u8 smac[`6`]; / ETH_ALEN /
6107	__u8 dmac[`6`]; / ETH_ALEN /
6108	};
6109
6110	struct bpf_redir_neigh {
6111	/ network family for lookup (AF_INET, AF_INET6) /
6112	__u32 nh_family;
6113	/ network address of nexthop; skips fib lookup to find gateway /
6114	union {
6115	__be32 ipv4_nh;
6116	__u32 ipv6_nh[`4`]; / in6_addr; network order /
6117	};
6118	};
6119
6120	/ bpf_check_mtu flags/
6121	enum bpf_check_mtu_flags {
6122	BPF_MTU_CHK_SEGS = (`1U` << `0`),
6123	};
6124
6125	enum bpf_check_mtu_ret {
6126	BPF_MTU_CHK_RET_SUCCESS, / check and lookup successful /
6127	BPF_MTU_CHK_RET_FRAG_NEEDED, / fragmentation required to fwd /
6128	BPF_MTU_CHK_RET_SEGS_TOOBIG, / GSO re-segmentation needed to fwd /
6129	};
6130
6131	enum bpf_task_fd_type {
6132	BPF_FD_TYPE_RAW_TRACEPOINT, / tp name /
6133	BPF_FD_TYPE_TRACEPOINT, / tp name /
6134	BPF_FD_TYPE_KPROBE, / (symbol + offset) or addr /
6135	BPF_FD_TYPE_KRETPROBE, / (symbol + offset) or addr /
6136	BPF_FD_TYPE_UPROBE, / filename + offset /
6137	BPF_FD_TYPE_URETPROBE, / filename + offset /
6138	};
6139
6140	enum {
6141	BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG = (`1U` << `0`),
6142	BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL = (`1U` << `1`),
6143	BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP = (`1U` << `2`),
6144	};
6145
6146	struct bpf_flow_keys {
6147	__u16 nhoff;
6148	__u16 thoff;
6149	__u16 addr_proto; / ETH_P_* of valid addrs /
6150	__u8 is_frag;
6151	__u8 is_first_frag;
6152	__u8 is_encap;
6153	__u8 ip_proto;
6154	__be16 n_proto;
6155	__be16 sport;
6156	__be16 dport;
6157	union {
6158	struct {
6159	__be32 ipv4_src;
6160	__be32 ipv4_dst;
6161	};
6162	struct {
6163	__u32 ipv6_src[`4`]; / in6_addr; network order /
6164	__u32 ipv6_dst[`4`]; / in6_addr; network order /
6165	};
6166	};
6167	__u32 flags;
6168	__be32 flow_label;
6169	};
6170
6171	struct bpf_func_info {
6172	__u32 insn_off;
6173	__u32 type_id;
6174	};
6175
6176	#define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
6177	#define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
6178
6179	struct bpf_line_info {
6180	__u32 insn_off;
6181	__u32 file_name_off;
6182	__u32 line_off;
6183	__u32 line_col;
6184	};
6185
6186	struct bpf_spin_lock {
6187	__u32 val;
6188	};
6189
6190	struct bpf_timer {
6191	__u64 :`64`;
6192	__u64 :`64`;
6193	} __attribute__((aligned(`8`)));
6194
6195	struct bpf_sysctl {
6196	__u32 write; / Sysctl is being read (= 0) or written (= 1).*
6197	* Allows 1,2,4-byte read, but no write.
6198	*/
6199	__u32 file_pos; / Sysctl file position to read from, write to.*
6200	* Allows 1,2,4-byte read an 4-byte write.
6201	*/
6202	};
6203
6204	struct bpf_sockopt {
6205	__bpf_md_ptr(struct bpf_sock *, sk);
6206	__bpf_md_ptr(void *, optval);
6207	__bpf_md_ptr(void *, optval_end);
6208
6209	__s32 level;
6210	__s32 optname;
6211	__s32 optlen;
6212	__s32 retval;
6213	};
6214
6215	struct bpf_pidns_info {
6216	__u32 pid;
6217	__u32 tgid;
6218	};
6219
6220	/ User accessible data for SK_LOOKUP programs. Add new fields at the end. /
6221	struct bpf_sk_lookup {
6222	union {
6223	__bpf_md_ptr(struct bpf_sock , sk); /* Selected socket /
6224	__u64 cookie; / Non-zero if socket was selected in PROG_TEST_RUN /
6225	};
6226
6227	__u32 family; / Protocol family (AF_INET, AF_INET6) /
6228	__u32 protocol; / IP protocol (IPPROTO_TCP, IPPROTO_UDP) /
6229	__u32 remote_ip4; / Network byte order /
6230	__u32 remote_ip6[`4`]; / Network byte order /
6231	__be16 remote_port; / Network byte order /
6232	__u16 :`16`; / Zero padding /
6233	__u32 local_ip4; / Network byte order /
6234	__u32 local_ip6[`4`]; / Network byte order /
6235	__u32 local_port; / Host byte order /
6236	};
6237
6238	/*
6239	* struct btf_ptr is used for typed pointer representation; the
6240	* type id is used to render the pointer data as the appropriate type
6241	* via the bpf_snprintf_btf() helper described above. A flags field -
6242	* potentially to specify additional details about the BTF pointer
6243	* (rather than its mode of display) - is included for future use.
6244	* Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
6245	*/
6246	struct btf_ptr {
6247	void *ptr;
6248	__u32 type_id;
6249	__u32 flags; / BTF ptr flags; unused at present. /
6250	};
6251
6252	/*
6253	* Flags to control bpf_snprintf_btf() behaviour.
6254	* - BTF_F_COMPACT: no formatting around type information
6255	* - BTF_F_NONAME: no struct/union member names/types
6256	* - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
6257	* equivalent to %px.
6258	* - BTF_F_ZERO: show zero-valued struct/union members; they
6259	* are not displayed by default
6260	*/
6261	enum {
6262	BTF_F_COMPACT = (`1ULL` << `0`),
6263	BTF_F_NONAME = (`1ULL` << `1`),
6264	BTF_F_PTR_RAW = (`1ULL` << `2`),
6265	BTF_F_ZERO = (`1ULL` << `3`),
6266	};
6267
6268	#endif /* __LINUX_BPF_H__ */
6269

source code of include/linux/bpf.h