1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the TCP module.
8 *
9 * Version: @(#)tcp.h 1.0.5 05/23/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 */
14#ifndef _TCP_H
15#define _TCP_H
16
17#define FASTRETRANS_DEBUG 1
18
19#include <linux/list.h>
20#include <linux/tcp.h>
21#include <linux/bug.h>
22#include <linux/slab.h>
23#include <linux/cache.h>
24#include <linux/percpu.h>
25#include <linux/skbuff.h>
26#include <linux/kref.h>
27#include <linux/ktime.h>
28#include <linux/indirect_call_wrapper.h>
29
30#include <net/inet_connection_sock.h>
31#include <net/inet_timewait_sock.h>
32#include <net/inet_hashtables.h>
33#include <net/checksum.h>
34#include <net/request_sock.h>
35#include <net/sock_reuseport.h>
36#include <net/sock.h>
37#include <net/snmp.h>
38#include <net/ip.h>
39#include <net/tcp_states.h>
40#include <net/inet_ecn.h>
41#include <net/dst.h>
42#include <net/mptcp.h>
43
44#include <linux/seq_file.h>
45#include <linux/memcontrol.h>
46#include <linux/bpf-cgroup.h>
47#include <linux/siphash.h>
48
49extern struct inet_hashinfo tcp_hashinfo;
50
51DECLARE_PER_CPU(unsigned int, tcp_orphan_count);
52int tcp_orphan_count_sum(void);
53
54void tcp_time_wait(struct sock *sk, int state, int timeo);
55
56#define MAX_TCP_HEADER L1_CACHE_ALIGN(128 + MAX_HEADER)
57#define MAX_TCP_OPTION_SPACE 40
58#define TCP_MIN_SND_MSS 48
59#define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
60
61/*
62 * Never offer a window over 32767 without using window scaling. Some
63 * poor stacks do signed 16bit maths!
64 */
65#define MAX_TCP_WINDOW 32767U
66
67/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
68#define TCP_MIN_MSS 88U
69
70/* The initial MTU to use for probing */
71#define TCP_BASE_MSS 1024
72
73/* probing interval, default to 10 minutes as per RFC4821 */
74#define TCP_PROBE_INTERVAL 600
75
76/* Specify interval when tcp mtu probing will stop */
77#define TCP_PROBE_THRESHOLD 8
78
79/* After receiving this amount of duplicate ACKs fast retransmit starts. */
80#define TCP_FASTRETRANS_THRESH 3
81
82/* Maximal number of ACKs sent quickly to accelerate slow-start. */
83#define TCP_MAX_QUICKACKS 16U
84
85/* Maximal number of window scale according to RFC1323 */
86#define TCP_MAX_WSCALE 14U
87
88/* urg_data states */
89#define TCP_URG_VALID 0x0100
90#define TCP_URG_NOTYET 0x0200
91#define TCP_URG_READ 0x0400
92
93#define TCP_RETR1 3 /*
94 * This is how many retries it does before it
95 * tries to figure out if the gateway is
96 * down. Minimal RFC value is 3; it corresponds
97 * to ~3sec-8min depending on RTO.
98 */
99
100#define TCP_RETR2 15 /*
101 * This should take at least
102 * 90 minutes to time out.
103 * RFC1122 says that the limit is 100 sec.
104 * 15 is ~13-30min depending on RTO.
105 */
106
107#define TCP_SYN_RETRIES 6 /* This is how many retries are done
108 * when active opening a connection.
109 * RFC1122 says the minimum retry MUST
110 * be at least 180secs. Nevertheless
111 * this value is corresponding to
112 * 63secs of retransmission with the
113 * current initial RTO.
114 */
115
116#define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
117 * when passive opening a connection.
118 * This is corresponding to 31secs of
119 * retransmission with the current
120 * initial RTO.
121 */
122
123#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
124 * state, about 60 seconds */
125#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
126 /* BSD style FIN_WAIT2 deadlock breaker.
127 * It used to be 3min, new value is 60sec,
128 * to combine FIN-WAIT-2 timeout with
129 * TIME-WAIT timer.
130 */
131#define TCP_FIN_TIMEOUT_MAX (120 * HZ) /* max TCP_LINGER2 value (two minutes) */
132
133#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
134#if HZ >= 100
135#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
136#define TCP_ATO_MIN ((unsigned)(HZ/25))
137#else
138#define TCP_DELACK_MIN 4U
139#define TCP_ATO_MIN 4U
140#endif
141#define TCP_RTO_MAX ((unsigned)(120*HZ))
142#define TCP_RTO_MIN ((unsigned)(HZ/5))
143#define TCP_TIMEOUT_MIN (2U) /* Min timeout for TCP timers in jiffies */
144#define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
145#define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
146 * used as a fallback RTO for the
147 * initial data transmission if no
148 * valid RTT sample has been acquired,
149 * most likely due to retrans in 3WHS.
150 */
151
152#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
153 * for local resources.
154 */
155#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
156#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
157#define TCP_KEEPALIVE_INTVL (75*HZ)
158
159#define MAX_TCP_KEEPIDLE 32767
160#define MAX_TCP_KEEPINTVL 32767
161#define MAX_TCP_KEEPCNT 127
162#define MAX_TCP_SYNCNT 127
163
164#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
165
166#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
167#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
168 * after this time. It should be equal
169 * (or greater than) TCP_TIMEWAIT_LEN
170 * to provide reliability equal to one
171 * provided by timewait state.
172 */
173#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
174 * timestamps. It must be less than
175 * minimal timewait lifetime.
176 */
177/*
178 * TCP option
179 */
180
181#define TCPOPT_NOP 1 /* Padding */
182#define TCPOPT_EOL 0 /* End of options */
183#define TCPOPT_MSS 2 /* Segment size negotiating */
184#define TCPOPT_WINDOW 3 /* Window scaling */
185#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
186#define TCPOPT_SACK 5 /* SACK Block */
187#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
188#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
189#define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */
190#define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
191#define TCPOPT_EXP 254 /* Experimental */
192/* Magic number to be after the option value for sharing TCP
193 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
194 */
195#define TCPOPT_FASTOPEN_MAGIC 0xF989
196#define TCPOPT_SMC_MAGIC 0xE2D4C3D9
197
198/*
199 * TCP option lengths
200 */
201
202#define TCPOLEN_MSS 4
203#define TCPOLEN_WINDOW 3
204#define TCPOLEN_SACK_PERM 2
205#define TCPOLEN_TIMESTAMP 10
206#define TCPOLEN_MD5SIG 18
207#define TCPOLEN_FASTOPEN_BASE 2
208#define TCPOLEN_EXP_FASTOPEN_BASE 4
209#define TCPOLEN_EXP_SMC_BASE 6
210
211/* But this is what stacks really send out. */
212#define TCPOLEN_TSTAMP_ALIGNED 12
213#define TCPOLEN_WSCALE_ALIGNED 4
214#define TCPOLEN_SACKPERM_ALIGNED 4
215#define TCPOLEN_SACK_BASE 2
216#define TCPOLEN_SACK_BASE_ALIGNED 4
217#define TCPOLEN_SACK_PERBLOCK 8
218#define TCPOLEN_MD5SIG_ALIGNED 20
219#define TCPOLEN_MSS_ALIGNED 4
220#define TCPOLEN_EXP_SMC_BASE_ALIGNED 8
221
222/* Flags in tp->nonagle */
223#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
224#define TCP_NAGLE_CORK 2 /* Socket is corked */
225#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
226
227/* TCP thin-stream limits */
228#define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
229
230/* TCP initial congestion window as per rfc6928 */
231#define TCP_INIT_CWND 10
232
233/* Bit Flags for sysctl_tcp_fastopen */
234#define TFO_CLIENT_ENABLE 1
235#define TFO_SERVER_ENABLE 2
236#define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
237
238/* Accept SYN data w/o any cookie option */
239#define TFO_SERVER_COOKIE_NOT_REQD 0x200
240
241/* Force enable TFO on all listeners, i.e., not requiring the
242 * TCP_FASTOPEN socket option.
243 */
244#define TFO_SERVER_WO_SOCKOPT1 0x400
245
246
247/* sysctl variables for tcp */
248extern int sysctl_tcp_max_orphans;
249extern long sysctl_tcp_mem[3];
250
251#define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
252#define TCP_RACK_STATIC_REO_WND 0x2 /* Use static RACK reo wnd */
253#define TCP_RACK_NO_DUPTHRESH 0x4 /* Do not use DUPACK threshold in RACK */
254
255extern atomic_long_t tcp_memory_allocated;
256DECLARE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc);
257
258extern struct percpu_counter tcp_sockets_allocated;
259extern unsigned long tcp_memory_pressure;
260
261/* optimized version of sk_under_memory_pressure() for TCP sockets */
262static inline bool tcp_under_memory_pressure(const struct sock *sk)
263{
264 if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
265 mem_cgroup_under_socket_pressure(sk->sk_memcg))
266 return true;
267
268 return READ_ONCE(tcp_memory_pressure);
269}
270/*
271 * The next routines deal with comparing 32 bit unsigned ints
272 * and worry about wraparound (automatic with unsigned arithmetic).
273 */
274
275static inline bool before(__u32 seq1, __u32 seq2)
276{
277 return (__s32)(seq1-seq2) < 0;
278}
279#define after(seq2, seq1) before(seq1, seq2)
280
281/* is s2<=s1<=s3 ? */
282static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3)
283{
284 return seq3 - seq2 >= seq1 - seq2;
285}
286
287static inline bool tcp_out_of_memory(struct sock *sk)
288{
289 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
290 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
291 return true;
292 return false;
293}
294
295static inline void tcp_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
296{
297 sk_wmem_queued_add(sk, -skb->truesize);
298 if (!skb_zcopy_pure(skb))
299 sk_mem_uncharge(sk, skb->truesize);
300 else
301 sk_mem_uncharge(sk, SKB_TRUESIZE(skb_end_offset(skb)));
302 __kfree_skb(skb);
303}
304
305void sk_forced_mem_schedule(struct sock *sk, int size);
306
307bool tcp_check_oom(struct sock *sk, int shift);
308
309
310extern struct proto tcp_prot;
311
312#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
313#define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field)
314#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
315#define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
316
317void tcp_tasklet_init(void);
318
319int tcp_v4_err(struct sk_buff *skb, u32);
320
321void tcp_shutdown(struct sock *sk, int how);
322
323int tcp_v4_early_demux(struct sk_buff *skb);
324int tcp_v4_rcv(struct sk_buff *skb);
325
326void tcp_remove_empty_skb(struct sock *sk);
327int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
328int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
329int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size);
330int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size,
331 int flags);
332int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,
333 size_t size, int flags);
334ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
335 size_t size, int flags);
336int tcp_send_mss(struct sock *sk, int *size_goal, int flags);
337void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle,
338 int size_goal);
339void tcp_release_cb(struct sock *sk);
340void tcp_wfree(struct sk_buff *skb);
341void tcp_write_timer_handler(struct sock *sk);
342void tcp_delack_timer_handler(struct sock *sk);
343int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
344int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
345void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
346void tcp_rcv_space_adjust(struct sock *sk);
347int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
348void tcp_twsk_destructor(struct sock *sk);
349ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
350 struct pipe_inode_info *pipe, size_t len,
351 unsigned int flags);
352struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
353 bool force_schedule);
354
355void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks);
356static inline void tcp_dec_quickack_mode(struct sock *sk,
357 const unsigned int pkts)
358{
359 struct inet_connection_sock *icsk = inet_csk(sk);
360
361 if (icsk->icsk_ack.quick) {
362 if (pkts >= icsk->icsk_ack.quick) {
363 icsk->icsk_ack.quick = 0;
364 /* Leaving quickack mode we deflate ATO. */
365 icsk->icsk_ack.ato = TCP_ATO_MIN;
366 } else
367 icsk->icsk_ack.quick -= pkts;
368 }
369}
370
371#define TCP_ECN_OK 1
372#define TCP_ECN_QUEUE_CWR 2
373#define TCP_ECN_DEMAND_CWR 4
374#define TCP_ECN_SEEN 8
375
376enum tcp_tw_status {
377 TCP_TW_SUCCESS = 0,
378 TCP_TW_RST = 1,
379 TCP_TW_ACK = 2,
380 TCP_TW_SYN = 3
381};
382
383
384enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
385 struct sk_buff *skb,
386 const struct tcphdr *th);
387struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
388 struct request_sock *req, bool fastopen,
389 bool *lost_race);
390int tcp_child_process(struct sock *parent, struct sock *child,
391 struct sk_buff *skb);
392void tcp_enter_loss(struct sock *sk);
393void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag);
394void tcp_clear_retrans(struct tcp_sock *tp);
395void tcp_update_metrics(struct sock *sk);
396void tcp_init_metrics(struct sock *sk);
397void tcp_metrics_init(void);
398bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst);
399void __tcp_close(struct sock *sk, long timeout);
400void tcp_close(struct sock *sk, long timeout);
401void tcp_init_sock(struct sock *sk);
402void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb);
403__poll_t tcp_poll(struct file *file, struct socket *sock,
404 struct poll_table_struct *wait);
405int tcp_getsockopt(struct sock *sk, int level, int optname,
406 char __user *optval, int __user *optlen);
407bool tcp_bpf_bypass_getsockopt(int level, int optname);
408int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
409 unsigned int optlen);
410void tcp_set_keepalive(struct sock *sk, int val);
411void tcp_syn_ack_timeout(const struct request_sock *req);
412int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
413 int flags, int *addr_len);
414int tcp_set_rcvlowat(struct sock *sk, int val);
415int tcp_set_window_clamp(struct sock *sk, int val);
416void tcp_update_recv_tstamps(struct sk_buff *skb,
417 struct scm_timestamping_internal *tss);
418void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
419 struct scm_timestamping_internal *tss);
420void tcp_data_ready(struct sock *sk);
421#ifdef CONFIG_MMU
422int tcp_mmap(struct file *file, struct socket *sock,
423 struct vm_area_struct *vma);
424#endif
425void tcp_parse_options(const struct net *net, const struct sk_buff *skb,
426 struct tcp_options_received *opt_rx,
427 int estab, struct tcp_fastopen_cookie *foc);
428const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
429
430/*
431 * BPF SKB-less helpers
432 */
433u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
434 struct tcphdr *th, u32 *cookie);
435u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
436 struct tcphdr *th, u32 *cookie);
437u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss);
438u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops,
439 const struct tcp_request_sock_ops *af_ops,
440 struct sock *sk, struct tcphdr *th);
441/*
442 * TCP v4 functions exported for the inet6 API
443 */
444
445void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
446void tcp_v4_mtu_reduced(struct sock *sk);
447void tcp_req_err(struct sock *sk, u32 seq, bool abort);
448void tcp_ld_RTO_revert(struct sock *sk, u32 seq);
449int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
450struct sock *tcp_create_openreq_child(const struct sock *sk,
451 struct request_sock *req,
452 struct sk_buff *skb);
453void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst);
454struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
455 struct request_sock *req,
456 struct dst_entry *dst,
457 struct request_sock *req_unhash,
458 bool *own_req);
459int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
460int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
461int tcp_connect(struct sock *sk);
462enum tcp_synack_type {
463 TCP_SYNACK_NORMAL,
464 TCP_SYNACK_FASTOPEN,
465 TCP_SYNACK_COOKIE,
466};
467struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
468 struct request_sock *req,
469 struct tcp_fastopen_cookie *foc,
470 enum tcp_synack_type synack_type,
471 struct sk_buff *syn_skb);
472int tcp_disconnect(struct sock *sk, int flags);
473
474void tcp_finish_connect(struct sock *sk, struct sk_buff *skb);
475int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size);
476void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
477
478/* From syncookies.c */
479struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
480 struct request_sock *req,
481 struct dst_entry *dst, u32 tsoff);
482int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th,
483 u32 cookie);
484struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb);
485struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
486 const struct tcp_request_sock_ops *af_ops,
487 struct sock *sk, struct sk_buff *skb);
488#ifdef CONFIG_SYN_COOKIES
489
490/* Syncookies use a monotonic timer which increments every 60 seconds.
491 * This counter is used both as a hash input and partially encoded into
492 * the cookie value. A cookie is only validated further if the delta
493 * between the current counter value and the encoded one is less than this,
494 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
495 * the counter advances immediately after a cookie is generated).
496 */
497#define MAX_SYNCOOKIE_AGE 2
498#define TCP_SYNCOOKIE_PERIOD (60 * HZ)
499#define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
500
501/* syncookies: remember time of last synqueue overflow
502 * But do not dirty this field too often (once per second is enough)
503 * It is racy as we do not hold a lock, but race is very minor.
504 */
505static inline void tcp_synq_overflow(const struct sock *sk)
506{
507 unsigned int last_overflow;
508 unsigned int now = jiffies;
509
510 if (sk->sk_reuseport) {
511 struct sock_reuseport *reuse;
512
513 reuse = rcu_dereference(sk->sk_reuseport_cb);
514 if (likely(reuse)) {
515 last_overflow = READ_ONCE(reuse->synq_overflow_ts);
516 if (!time_between32(now, last_overflow,
517 last_overflow + HZ))
518 WRITE_ONCE(reuse->synq_overflow_ts, now);
519 return;
520 }
521 }
522
523 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp);
524 if (!time_between32(now, last_overflow, last_overflow + HZ))
525 WRITE_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp, now);
526}
527
528/* syncookies: no recent synqueue overflow on this listening socket? */
529static inline bool tcp_synq_no_recent_overflow(const struct sock *sk)
530{
531 unsigned int last_overflow;
532 unsigned int now = jiffies;
533
534 if (sk->sk_reuseport) {
535 struct sock_reuseport *reuse;
536
537 reuse = rcu_dereference(sk->sk_reuseport_cb);
538 if (likely(reuse)) {
539 last_overflow = READ_ONCE(reuse->synq_overflow_ts);
540 return !time_between32(now, last_overflow - HZ,
541 last_overflow +
542 TCP_SYNCOOKIE_VALID);
543 }
544 }
545
546 last_overflow = READ_ONCE(tcp_sk(sk)->rx_opt.ts_recent_stamp);
547
548 /* If last_overflow <= jiffies <= last_overflow + TCP_SYNCOOKIE_VALID,
549 * then we're under synflood. However, we have to use
550 * 'last_overflow - HZ' as lower bound. That's because a concurrent
551 * tcp_synq_overflow() could update .ts_recent_stamp after we read
552 * jiffies but before we store .ts_recent_stamp into last_overflow,
553 * which could lead to rejecting a valid syncookie.
554 */
555 return !time_between32(now, last_overflow - HZ,
556 last_overflow + TCP_SYNCOOKIE_VALID);
557}
558
559static inline u32 tcp_cookie_time(void)
560{
561 u64 val = get_jiffies_64();
562
563 do_div(val, TCP_SYNCOOKIE_PERIOD);
564 return val;
565}
566
567u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
568 u16 *mssp);
569__u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
570u64 cookie_init_timestamp(struct request_sock *req, u64 now);
571bool cookie_timestamp_decode(const struct net *net,
572 struct tcp_options_received *opt);
573bool cookie_ecn_ok(const struct tcp_options_received *opt,
574 const struct net *net, const struct dst_entry *dst);
575
576/* From net/ipv6/syncookies.c */
577int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
578 u32 cookie);
579struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
580
581u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
582 const struct tcphdr *th, u16 *mssp);
583__u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss);
584#endif
585/* tcp_output.c */
586
587void tcp_skb_entail(struct sock *sk, struct sk_buff *skb);
588void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb);
589void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
590 int nonagle);
591int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
592int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
593void tcp_retransmit_timer(struct sock *sk);
594void tcp_xmit_retransmit_queue(struct sock *);
595void tcp_simple_retransmit(struct sock *);
596void tcp_enter_recovery(struct sock *sk, bool ece_ack);
597int tcp_trim_head(struct sock *, struct sk_buff *, u32);
598enum tcp_queue {
599 TCP_FRAG_IN_WRITE_QUEUE,
600 TCP_FRAG_IN_RTX_QUEUE,
601};
602int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
603 struct sk_buff *skb, u32 len,
604 unsigned int mss_now, gfp_t gfp);
605
606void tcp_send_probe0(struct sock *);
607void tcp_send_partial(struct sock *);
608int tcp_write_wakeup(struct sock *, int mib);
609void tcp_send_fin(struct sock *sk);
610void tcp_send_active_reset(struct sock *sk, gfp_t priority);
611int tcp_send_synack(struct sock *);
612void tcp_push_one(struct sock *, unsigned int mss_now);
613void __tcp_send_ack(struct sock *sk, u32 rcv_nxt);
614void tcp_send_ack(struct sock *sk);
615void tcp_send_delayed_ack(struct sock *sk);
616void tcp_send_loss_probe(struct sock *sk);
617bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto);
618void tcp_skb_collapse_tstamp(struct sk_buff *skb,
619 const struct sk_buff *next_skb);
620
621/* tcp_input.c */
622void tcp_rearm_rto(struct sock *sk);
623void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req);
624void tcp_reset(struct sock *sk, struct sk_buff *skb);
625void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb);
626void tcp_fin(struct sock *sk);
627void tcp_check_space(struct sock *sk);
628
629/* tcp_timer.c */
630void tcp_init_xmit_timers(struct sock *);
631static inline void tcp_clear_xmit_timers(struct sock *sk)
632{
633 if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1)
634 __sock_put(sk);
635
636 if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1)
637 __sock_put(sk);
638
639 inet_csk_clear_xmit_timers(sk);
640}
641
642unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
643unsigned int tcp_current_mss(struct sock *sk);
644u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when);
645
646/* Bound MSS / TSO packet size with the half of the window */
647static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
648{
649 int cutoff;
650
651 /* When peer uses tiny windows, there is no use in packetizing
652 * to sub-MSS pieces for the sake of SWS or making sure there
653 * are enough packets in the pipe for fast recovery.
654 *
655 * On the other hand, for extremely large MSS devices, handling
656 * smaller than MSS windows in this way does make sense.
657 */
658 if (tp->max_window > TCP_MSS_DEFAULT)
659 cutoff = (tp->max_window >> 1);
660 else
661 cutoff = tp->max_window;
662
663 if (cutoff && pktsize > cutoff)
664 return max_t(int, cutoff, 68U - tp->tcp_header_len);
665 else
666 return pktsize;
667}
668
669/* tcp.c */
670void tcp_get_info(struct sock *, struct tcp_info *);
671
672/* Read 'sendfile()'-style from a TCP socket */
673int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
674 sk_read_actor_t recv_actor);
675int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
676struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off);
677void tcp_read_done(struct sock *sk, size_t len);
678
679void tcp_initialize_rcv_mss(struct sock *sk);
680
681int tcp_mtu_to_mss(struct sock *sk, int pmtu);
682int tcp_mss_to_mtu(struct sock *sk, int mss);
683void tcp_mtup_init(struct sock *sk);
684
685static inline void tcp_bound_rto(const struct sock *sk)
686{
687 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
688 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
689}
690
691static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
692{
693 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us);
694}
695
696static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
697{
698 /* mptcp hooks are only on the slow path */
699 if (sk_is_mptcp((struct sock *)tp))
700 return;
701
702 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
703 ntohl(TCP_FLAG_ACK) |
704 snd_wnd);
705}
706
707static inline void tcp_fast_path_on(struct tcp_sock *tp)
708{
709 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
710}
711
712static inline void tcp_fast_path_check(struct sock *sk)
713{
714 struct tcp_sock *tp = tcp_sk(sk);
715
716 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) &&
717 tp->rcv_wnd &&
718 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
719 !tp->urg_data)
720 tcp_fast_path_on(tp);
721}
722
723/* Compute the actual rto_min value */
724static inline u32 tcp_rto_min(struct sock *sk)
725{
726 const struct dst_entry *dst = __sk_dst_get(sk);
727 u32 rto_min = inet_csk(sk)->icsk_rto_min;
728
729 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
730 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
731 return rto_min;
732}
733
734static inline u32 tcp_rto_min_us(struct sock *sk)
735{
736 return jiffies_to_usecs(tcp_rto_min(sk));
737}
738
739static inline bool tcp_ca_dst_locked(const struct dst_entry *dst)
740{
741 return dst_metric_locked(dst, RTAX_CC_ALGO);
742}
743
744/* Minimum RTT in usec. ~0 means not available. */
745static inline u32 tcp_min_rtt(const struct tcp_sock *tp)
746{
747 return minmax_get(&tp->rtt_min);
748}
749
750/* Compute the actual receive window we are currently advertising.
751 * Rcv_nxt can be after the window if our peer push more data
752 * than the offered window.
753 */
754static inline u32 tcp_receive_window(const struct tcp_sock *tp)
755{
756 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
757
758 if (win < 0)
759 win = 0;
760 return (u32) win;
761}
762
763/* Choose a new window, without checks for shrinking, and without
764 * scaling applied to the result. The caller does these things
765 * if necessary. This is a "raw" window selection.
766 */
767u32 __tcp_select_window(struct sock *sk);
768
769void tcp_send_window_probe(struct sock *sk);
770
771/* TCP uses 32bit jiffies to save some space.
772 * Note that this is different from tcp_time_stamp, which
773 * historically has been the same until linux-4.13.
774 */
775#define tcp_jiffies32 ((u32)jiffies)
776
777/*
778 * Deliver a 32bit value for TCP timestamp option (RFC 7323)
779 * It is no longer tied to jiffies, but to 1 ms clock.
780 * Note: double check if you want to use tcp_jiffies32 instead of this.
781 */
782#define TCP_TS_HZ 1000
783
784static inline u64 tcp_clock_ns(void)
785{
786 return ktime_get_ns();
787}
788
789static inline u64 tcp_clock_us(void)
790{
791 return div_u64(tcp_clock_ns(), NSEC_PER_USEC);
792}
793
794/* This should only be used in contexts where tp->tcp_mstamp is up to date */
795static inline u32 tcp_time_stamp(const struct tcp_sock *tp)
796{
797 return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ);
798}
799
800/* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */
801static inline u32 tcp_ns_to_ts(u64 ns)
802{
803 return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ);
804}
805
806/* Could use tcp_clock_us() / 1000, but this version uses a single divide */
807static inline u32 tcp_time_stamp_raw(void)
808{
809 return tcp_ns_to_ts(tcp_clock_ns());
810}
811
812void tcp_mstamp_refresh(struct tcp_sock *tp);
813
814static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0)
815{
816 return max_t(s64, t1 - t0, 0);
817}
818
819static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
820{
821 return tcp_ns_to_ts(skb->skb_mstamp_ns);
822}
823
824/* provide the departure time in us unit */
825static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb)
826{
827 return div_u64(skb->skb_mstamp_ns, NSEC_PER_USEC);
828}
829
830
831#define tcp_flag_byte(th) (((u_int8_t *)th)[13])
832
833#define TCPHDR_FIN 0x01
834#define TCPHDR_SYN 0x02
835#define TCPHDR_RST 0x04
836#define TCPHDR_PSH 0x08
837#define TCPHDR_ACK 0x10
838#define TCPHDR_URG 0x20
839#define TCPHDR_ECE 0x40
840#define TCPHDR_CWR 0x80
841
842#define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
843
844/* This is what the send packet queuing engine uses to pass
845 * TCP per-packet control information to the transmission code.
846 * We also store the host-order sequence numbers in here too.
847 * This is 44 bytes if IPV6 is enabled.
848 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
849 */
850struct tcp_skb_cb {
851 __u32 seq; /* Starting sequence number */
852 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
853 union {
854 /* Note : tcp_tw_isn is used in input path only
855 * (isn chosen by tcp_timewait_state_process())
856 *
857 * tcp_gso_segs/size are used in write queue only,
858 * cf tcp_skb_pcount()/tcp_skb_mss()
859 */
860 __u32 tcp_tw_isn;
861 struct {
862 u16 tcp_gso_segs;
863 u16 tcp_gso_size;
864 };
865 };
866 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */
867
868 __u8 sacked; /* State flags for SACK. */
869#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
870#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
871#define TCPCB_LOST 0x04 /* SKB is lost */
872#define TCPCB_TAGBITS 0x07 /* All tag bits */
873#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp_ns) */
874#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
875#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
876 TCPCB_REPAIRED)
877
878 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
879 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */
880 eor:1, /* Is skb MSG_EOR marked? */
881 has_rxtstamp:1, /* SKB has a RX timestamp */
882 unused:5;
883 __u32 ack_seq; /* Sequence number ACK'd */
884 union {
885 struct {
886#define TCPCB_DELIVERED_CE_MASK ((1U<<20) - 1)
887 /* There is space for up to 24 bytes */
888 __u32 is_app_limited:1, /* cwnd not fully used? */
889 delivered_ce:20,
890 unused:11;
891 /* pkts S/ACKed so far upon tx of skb, incl retrans: */
892 __u32 delivered;
893 /* start of send pipeline phase */
894 u64 first_tx_mstamp;
895 /* when we reached the "delivered" count */
896 u64 delivered_mstamp;
897 } tx; /* only used for outgoing skbs */
898 union {
899 struct inet_skb_parm h4;
900#if IS_ENABLED(CONFIG_IPV6)
901 struct inet6_skb_parm h6;
902#endif
903 } header; /* For incoming skbs */
904 };
905};
906
907#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
908
909extern const struct inet_connection_sock_af_ops ipv4_specific;
910
911#if IS_ENABLED(CONFIG_IPV6)
912/* This is the variant of inet6_iif() that must be used by TCP,
913 * as TCP moves IP6CB into a different location in skb->cb[]
914 */
915static inline int tcp_v6_iif(const struct sk_buff *skb)
916{
917 return TCP_SKB_CB(skb)->header.h6.iif;
918}
919
920static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb)
921{
922 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
923
924 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif;
925}
926
927/* TCP_SKB_CB reference means this can not be used from early demux */
928static inline int tcp_v6_sdif(const struct sk_buff *skb)
929{
930#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
931 if (skb && ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags))
932 return TCP_SKB_CB(skb)->header.h6.iif;
933#endif
934 return 0;
935}
936
937extern const struct inet_connection_sock_af_ops ipv6_specific;
938
939INDIRECT_CALLABLE_DECLARE(void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb));
940INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb));
941void tcp_v6_early_demux(struct sk_buff *skb);
942
943#endif
944
945/* TCP_SKB_CB reference means this can not be used from early demux */
946static inline int tcp_v4_sdif(struct sk_buff *skb)
947{
948#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
949 if (skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
950 return TCP_SKB_CB(skb)->header.h4.iif;
951#endif
952 return 0;
953}
954
955/* Due to TSO, an SKB can be composed of multiple actual
956 * packets. To keep these tracked properly, we use this.
957 */
958static inline int tcp_skb_pcount(const struct sk_buff *skb)
959{
960 return TCP_SKB_CB(skb)->tcp_gso_segs;
961}
962
963static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs)
964{
965 TCP_SKB_CB(skb)->tcp_gso_segs = segs;
966}
967
968static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs)
969{
970 TCP_SKB_CB(skb)->tcp_gso_segs += segs;
971}
972
973/* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
974static inline int tcp_skb_mss(const struct sk_buff *skb)
975{
976 return TCP_SKB_CB(skb)->tcp_gso_size;
977}
978
979static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb)
980{
981 return likely(!TCP_SKB_CB(skb)->eor);
982}
983
984static inline bool tcp_skb_can_collapse(const struct sk_buff *to,
985 const struct sk_buff *from)
986{
987 return likely(tcp_skb_can_collapse_to(to) &&
988 mptcp_skb_can_collapse(to, from) &&
989 skb_pure_zcopy_same(to, from));
990}
991
992/* Events passed to congestion control interface */
993enum tcp_ca_event {
994 CA_EVENT_TX_START, /* first transmit when no packets in flight */
995 CA_EVENT_CWND_RESTART, /* congestion window restart */
996 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
997 CA_EVENT_LOSS, /* loss timeout */
998 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
999 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
1000};
1001
1002/* Information about inbound ACK, passed to cong_ops->in_ack_event() */
1003enum tcp_ca_ack_event_flags {
1004 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */
1005 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */
1006 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */
1007};
1008
1009/*
1010 * Interface for adding new TCP congestion control handlers
1011 */
1012#define TCP_CA_NAME_MAX 16
1013#define TCP_CA_MAX 128
1014#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
1015
1016#define TCP_CA_UNSPEC 0
1017
1018/* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
1019#define TCP_CONG_NON_RESTRICTED 0x1
1020/* Requires ECN/ECT set on all packets */
1021#define TCP_CONG_NEEDS_ECN 0x2
1022#define TCP_CONG_MASK (TCP_CONG_NON_RESTRICTED | TCP_CONG_NEEDS_ECN)
1023
1024union tcp_cc_info;
1025
1026struct ack_sample {
1027 u32 pkts_acked;
1028 s32 rtt_us;
1029 u32 in_flight;
1030};
1031
1032/* A rate sample measures the number of (original/retransmitted) data
1033 * packets delivered "delivered" over an interval of time "interval_us".
1034 * The tcp_rate.c code fills in the rate sample, and congestion
1035 * control modules that define a cong_control function to run at the end
1036 * of ACK processing can optionally chose to consult this sample when
1037 * setting cwnd and pacing rate.
1038 * A sample is invalid if "delivered" or "interval_us" is negative.
1039 */
1040struct rate_sample {
1041 u64 prior_mstamp; /* starting timestamp for interval */
1042 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */
1043 u32 prior_delivered_ce;/* tp->delivered_ce at "prior_mstamp" */
1044 s32 delivered; /* number of packets delivered over interval */
1045 s32 delivered_ce; /* number of packets delivered w/ CE marks*/
1046 long interval_us; /* time for tp->delivered to incr "delivered" */
1047 u32 snd_interval_us; /* snd interval for delivered packets */
1048 u32 rcv_interval_us; /* rcv interval for delivered packets */
1049 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */
1050 int losses; /* number of packets marked lost upon ACK */
1051 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */
1052 u32 prior_in_flight; /* in flight before this ACK */
1053 u32 last_end_seq; /* end_seq of most recently ACKed packet */
1054 bool is_app_limited; /* is sample from packet with bubble in pipe? */
1055 bool is_retrans; /* is sample from retransmission? */
1056 bool is_ack_delayed; /* is this (likely) a delayed ACK? */
1057};
1058
1059struct tcp_congestion_ops {
1060/* fast path fields are put first to fill one cache line */
1061
1062 /* return slow start threshold (required) */
1063 u32 (*ssthresh)(struct sock *sk);
1064
1065 /* do new cwnd calculation (required) */
1066 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked);
1067
1068 /* call before changing ca_state (optional) */
1069 void (*set_state)(struct sock *sk, u8 new_state);
1070
1071 /* call when cwnd event occurs (optional) */
1072 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
1073
1074 /* call when ack arrives (optional) */
1075 void (*in_ack_event)(struct sock *sk, u32 flags);
1076
1077 /* hook for packet ack accounting (optional) */
1078 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);
1079
1080 /* override sysctl_tcp_min_tso_segs */
1081 u32 (*min_tso_segs)(struct sock *sk);
1082
1083 /* call when packets are delivered to update cwnd and pacing rate,
1084 * after all the ca_state processing. (optional)
1085 */
1086 void (*cong_control)(struct sock *sk, const struct rate_sample *rs);
1087
1088
1089 /* new value of cwnd after loss (required) */
1090 u32 (*undo_cwnd)(struct sock *sk);
1091 /* returns the multiplier used in tcp_sndbuf_expand (optional) */
1092 u32 (*sndbuf_expand)(struct sock *sk);
1093
1094/* control/slow paths put last */
1095 /* get info for inet_diag (optional) */
1096 size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
1097 union tcp_cc_info *info);
1098
1099 char name[TCP_CA_NAME_MAX];
1100 struct module *owner;
1101 struct list_head list;
1102 u32 key;
1103 u32 flags;
1104
1105 /* initialize private data (optional) */
1106 void (*init)(struct sock *sk);
1107 /* cleanup private data (optional) */
1108 void (*release)(struct sock *sk);
1109} ____cacheline_aligned_in_smp;
1110
1111int tcp_register_congestion_control(struct tcp_congestion_ops *type);
1112void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
1113
1114void tcp_assign_congestion_control(struct sock *sk);
1115void tcp_init_congestion_control(struct sock *sk);
1116void tcp_cleanup_congestion_control(struct sock *sk);
1117int tcp_set_default_congestion_control(struct net *net, const char *name);
1118void tcp_get_default_congestion_control(struct net *net, char *name);
1119void tcp_get_available_congestion_control(char *buf, size_t len);
1120void tcp_get_allowed_congestion_control(char *buf, size_t len);
1121int tcp_set_allowed_congestion_control(char *allowed);
1122int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
1123 bool cap_net_admin);
1124u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
1125void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
1126
1127u32 tcp_reno_ssthresh(struct sock *sk);
1128u32 tcp_reno_undo_cwnd(struct sock *sk);
1129void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked);
1130extern struct tcp_congestion_ops tcp_reno;
1131
1132struct tcp_congestion_ops *tcp_ca_find(const char *name);
1133struct tcp_congestion_ops *tcp_ca_find_key(u32 key);
1134u32 tcp_ca_get_key_by_name(struct net *net, const char *name, bool *ecn_ca);
1135#ifdef CONFIG_INET
1136char *tcp_ca_get_name_by_key(u32 key, char *buffer);
1137#else
1138static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer)
1139{
1140 return NULL;
1141}
1142#endif
1143
1144static inline bool tcp_ca_needs_ecn(const struct sock *sk)
1145{
1146 const struct inet_connection_sock *icsk = inet_csk(sk);
1147
1148 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
1149}
1150
1151static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
1152{
1153 const struct inet_connection_sock *icsk = inet_csk(sk);
1154
1155 if (icsk->icsk_ca_ops->cwnd_event)
1156 icsk->icsk_ca_ops->cwnd_event(sk, event);
1157}
1158
1159/* From tcp_cong.c */
1160void tcp_set_ca_state(struct sock *sk, const u8 ca_state);
1161
1162/* From tcp_rate.c */
1163void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
1164void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
1165 struct rate_sample *rs);
1166void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
1167 bool is_sack_reneg, struct rate_sample *rs);
1168void tcp_rate_check_app_limited(struct sock *sk);
1169
1170static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)
1171{
1172 return t1 > t2 || (t1 == t2 && after(seq1, seq2));
1173}
1174
1175/* These functions determine how the current flow behaves in respect of SACK
1176 * handling. SACK is negotiated with the peer, and therefore it can vary
1177 * between different flows.
1178 *
1179 * tcp_is_sack - SACK enabled
1180 * tcp_is_reno - No SACK
1181 */
1182static inline int tcp_is_sack(const struct tcp_sock *tp)
1183{
1184 return likely(tp->rx_opt.sack_ok);
1185}
1186
1187static inline bool tcp_is_reno(const struct tcp_sock *tp)
1188{
1189 return !tcp_is_sack(tp);
1190}
1191
1192static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
1193{
1194 return tp->sacked_out + tp->lost_out;
1195}
1196
1197/* This determines how many packets are "in the network" to the best
1198 * of our knowledge. In many cases it is conservative, but where
1199 * detailed information is available from the receiver (via SACK
1200 * blocks etc.) we can make more aggressive calculations.
1201 *
1202 * Use this for decisions involving congestion control, use just
1203 * tp->packets_out to determine if the send queue is empty or not.
1204 *
1205 * Read this equation as:
1206 *
1207 * "Packets sent once on transmission queue" MINUS
1208 * "Packets left network, but not honestly ACKed yet" PLUS
1209 * "Packets fast retransmitted"
1210 */
1211static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
1212{
1213 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
1214}
1215
1216#define TCP_INFINITE_SSTHRESH 0x7fffffff
1217
1218static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp)
1219{
1220 return tp->snd_cwnd;
1221}
1222
1223static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val)
1224{
1225 WARN_ON_ONCE((int)val <= 0);
1226 tp->snd_cwnd = val;
1227}
1228
1229static inline bool tcp_in_slow_start(const struct tcp_sock *tp)
1230{
1231 return tcp_snd_cwnd(tp) < tp->snd_ssthresh;
1232}
1233
1234static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
1235{
1236 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
1237}
1238
1239static inline bool tcp_in_cwnd_reduction(const struct sock *sk)
1240{
1241 return (TCPF_CA_CWR | TCPF_CA_Recovery) &
1242 (1 << inet_csk(sk)->icsk_ca_state);
1243}
1244
1245/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1246 * The exception is cwnd reduction phase, when cwnd is decreasing towards
1247 * ssthresh.
1248 */
1249static inline __u32 tcp_current_ssthresh(const struct sock *sk)
1250{
1251 const struct tcp_sock *tp = tcp_sk(sk);
1252
1253 if (tcp_in_cwnd_reduction(sk))
1254 return tp->snd_ssthresh;
1255 else
1256 return max(tp->snd_ssthresh,
1257 ((tcp_snd_cwnd(tp) >> 1) +
1258 (tcp_snd_cwnd(tp) >> 2)));
1259}
1260
1261/* Use define here intentionally to get WARN_ON location shown at the caller */
1262#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
1263
1264void tcp_enter_cwr(struct sock *sk);
1265__u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst);
1266
1267/* The maximum number of MSS of available cwnd for which TSO defers
1268 * sending if not using sysctl_tcp_tso_win_divisor.
1269 */
1270static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp)
1271{
1272 return 3;
1273}
1274
1275/* Returns end sequence number of the receiver's advertised window */
1276static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
1277{
1278 return tp->snd_una + tp->snd_wnd;
1279}
1280
1281/* We follow the spirit of RFC2861 to validate cwnd but implement a more
1282 * flexible approach. The RFC suggests cwnd should not be raised unless
1283 * it was fully used previously. And that's exactly what we do in
1284 * congestion avoidance mode. But in slow start we allow cwnd to grow
1285 * as long as the application has used half the cwnd.
1286 * Example :
1287 * cwnd is 10 (IW10), but application sends 9 frames.
1288 * We allow cwnd to reach 18 when all frames are ACKed.
1289 * This check is safe because it's as aggressive as slow start which already
1290 * risks 100% overshoot. The advantage is that we discourage application to
1291 * either send more filler packets or data to artificially blow up the cwnd
1292 * usage, and allow application-limited process to probe bw more aggressively.
1293 */
1294static inline bool tcp_is_cwnd_limited(const struct sock *sk)
1295{
1296 const struct tcp_sock *tp = tcp_sk(sk);
1297
1298 /* If in slow start, ensure cwnd grows to twice what was ACKed. */
1299 if (tcp_in_slow_start(tp))
1300 return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out;
1301
1302 return tp->is_cwnd_limited;
1303}
1304
1305/* BBR congestion control needs pacing.
1306 * Same remark for SO_MAX_PACING_RATE.
1307 * sch_fq packet scheduler is efficiently handling pacing,
1308 * but is not always installed/used.
1309 * Return true if TCP stack should pace packets itself.
1310 */
1311static inline bool tcp_needs_internal_pacing(const struct sock *sk)
1312{
1313 return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED;
1314}
1315
1316/* Estimates in how many jiffies next packet for this flow can be sent.
1317 * Scheduling a retransmit timer too early would be silly.
1318 */
1319static inline unsigned long tcp_pacing_delay(const struct sock *sk)
1320{
1321 s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache;
1322
1323 return delay > 0 ? nsecs_to_jiffies(delay) : 0;
1324}
1325
1326static inline void tcp_reset_xmit_timer(struct sock *sk,
1327 const int what,
1328 unsigned long when,
1329 const unsigned long max_when)
1330{
1331 inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk),
1332 max_when);
1333}
1334
1335/* Something is really bad, we could not queue an additional packet,
1336 * because qdisc is full or receiver sent a 0 window, or we are paced.
1337 * We do not want to add fuel to the fire, or abort too early,
1338 * so make sure the timer we arm now is at least 200ms in the future,
1339 * regardless of current icsk_rto value (as it could be ~2ms)
1340 */
1341static inline unsigned long tcp_probe0_base(const struct sock *sk)
1342{
1343 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN);
1344}
1345
1346/* Variant of inet_csk_rto_backoff() used for zero window probes */
1347static inline unsigned long tcp_probe0_when(const struct sock *sk,
1348 unsigned long max_when)
1349{
1350 u8 backoff = min_t(u8, ilog2(TCP_RTO_MAX / TCP_RTO_MIN) + 1,
1351 inet_csk(sk)->icsk_backoff);
1352 u64 when = (u64)tcp_probe0_base(sk) << backoff;
1353
1354 return (unsigned long)min_t(u64, when, max_when);
1355}
1356
1357static inline void tcp_check_probe_timer(struct sock *sk)
1358{
1359 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending)
1360 tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
1361 tcp_probe0_base(sk), TCP_RTO_MAX);
1362}
1363
1364static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
1365{
1366 tp->snd_wl1 = seq;
1367}
1368
1369static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
1370{
1371 tp->snd_wl1 = seq;
1372}
1373
1374/*
1375 * Calculate(/check) TCP checksum
1376 */
1377static inline __sum16 tcp_v4_check(int len, __be32 saddr,
1378 __be32 daddr, __wsum base)
1379{
1380 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_TCP, base);
1381}
1382
1383static inline bool tcp_checksum_complete(struct sk_buff *skb)
1384{
1385 return !skb_csum_unnecessary(skb) &&
1386 __skb_checksum_complete(skb);
1387}
1388
1389bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1390 enum skb_drop_reason *reason);
1391
1392
1393int tcp_filter(struct sock *sk, struct sk_buff *skb);
1394void tcp_set_state(struct sock *sk, int state);
1395void tcp_done(struct sock *sk);
1396int tcp_abort(struct sock *sk, int err);
1397
1398static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
1399{
1400 rx_opt->dsack = 0;
1401 rx_opt->num_sacks = 0;
1402}
1403
1404void tcp_cwnd_restart(struct sock *sk, s32 delta);
1405
1406static inline void tcp_slow_start_after_idle_check(struct sock *sk)
1407{
1408 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
1409 struct tcp_sock *tp = tcp_sk(sk);
1410 s32 delta;
1411
1412 if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) ||
1413 tp->packets_out || ca_ops->cong_control)
1414 return;
1415 delta = tcp_jiffies32 - tp->lsndtime;
1416 if (delta > inet_csk(sk)->icsk_rto)
1417 tcp_cwnd_restart(sk, delta);
1418}
1419
1420/* Determine a window scaling and initial window to offer. */
1421void tcp_select_initial_window(const struct sock *sk, int __space,
1422 __u32 mss, __u32 *rcv_wnd,
1423 __u32 *window_clamp, int wscale_ok,
1424 __u8 *rcv_wscale, __u32 init_rcv_wnd);
1425
1426static inline int tcp_win_from_space(const struct sock *sk, int space)
1427{
1428 int tcp_adv_win_scale = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_adv_win_scale);
1429
1430 return tcp_adv_win_scale <= 0 ?
1431 (space>>(-tcp_adv_win_scale)) :
1432 space - (space>>tcp_adv_win_scale);
1433}
1434
1435/* Note: caller must be prepared to deal with negative returns */
1436static inline int tcp_space(const struct sock *sk)
1437{
1438 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) -
1439 READ_ONCE(sk->sk_backlog.len) -
1440 atomic_read(&sk->sk_rmem_alloc));
1441}
1442
1443static inline int tcp_full_space(const struct sock *sk)
1444{
1445 return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf));
1446}
1447
1448static inline void tcp_adjust_rcv_ssthresh(struct sock *sk)
1449{
1450 int unused_mem = sk_unused_reserved_mem(sk);
1451 struct tcp_sock *tp = tcp_sk(sk);
1452
1453 tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
1454 if (unused_mem)
1455 tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh,
1456 tcp_win_from_space(sk, unused_mem));
1457}
1458
1459void tcp_cleanup_rbuf(struct sock *sk, int copied);
1460
1461/* We provision sk_rcvbuf around 200% of sk_rcvlowat.
1462 * If 87.5 % (7/8) of the space has been consumed, we want to override
1463 * SO_RCVLOWAT constraint, since we are receiving skbs with too small
1464 * len/truesize ratio.
1465 */
1466static inline bool tcp_rmem_pressure(const struct sock *sk)
1467{
1468 int rcvbuf, threshold;
1469
1470 if (tcp_under_memory_pressure(sk))
1471 return true;
1472
1473 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
1474 threshold = rcvbuf - (rcvbuf >> 3);
1475
1476 return atomic_read(&sk->sk_rmem_alloc) > threshold;
1477}
1478
1479static inline bool tcp_epollin_ready(const struct sock *sk, int target)
1480{
1481 const struct tcp_sock *tp = tcp_sk(sk);
1482 int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq);
1483
1484 if (avail <= 0)
1485 return false;
1486
1487 return (avail >= target) || tcp_rmem_pressure(sk) ||
1488 (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss);
1489}
1490
1491extern void tcp_openreq_init_rwin(struct request_sock *req,
1492 const struct sock *sk_listener,
1493 const struct dst_entry *dst);
1494
1495void tcp_enter_memory_pressure(struct sock *sk);
1496void tcp_leave_memory_pressure(struct sock *sk);
1497
1498static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1499{
1500 struct net *net = sock_net((struct sock *)tp);
1501
1502 return tp->keepalive_intvl ? :
1503 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl);
1504}
1505
1506static inline int keepalive_time_when(const struct tcp_sock *tp)
1507{
1508 struct net *net = sock_net((struct sock *)tp);
1509
1510 return tp->keepalive_time ? :
1511 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time);
1512}
1513
1514static inline int keepalive_probes(const struct tcp_sock *tp)
1515{
1516 struct net *net = sock_net((struct sock *)tp);
1517
1518 return tp->keepalive_probes ? :
1519 READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes);
1520}
1521
1522static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
1523{
1524 const struct inet_connection_sock *icsk = &tp->inet_conn;
1525
1526 return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime,
1527 tcp_jiffies32 - tp->rcv_tstamp);
1528}
1529
1530static inline int tcp_fin_time(const struct sock *sk)
1531{
1532 int fin_timeout = tcp_sk(sk)->linger2 ? :
1533 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fin_timeout);
1534 const int rto = inet_csk(sk)->icsk_rto;
1535
1536 if (fin_timeout < (rto << 2) - (rto >> 1))
1537 fin_timeout = (rto << 2) - (rto >> 1);
1538
1539 return fin_timeout;
1540}
1541
1542static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt,
1543 int paws_win)
1544{
1545 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1546 return true;
1547 if (unlikely(!time_before32(ktime_get_seconds(),
1548 rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)))
1549 return true;
1550 /*
1551 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
1552 * then following tcp messages have valid values. Ignore 0 value,
1553 * or else 'negative' tsval might forbid us to accept their packets.
1554 */
1555 if (!rx_opt->ts_recent)
1556 return true;
1557 return false;
1558}
1559
1560static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
1561 int rst)
1562{
1563 if (tcp_paws_check(rx_opt, 0))
1564 return false;
1565
1566 /* RST segments are not recommended to carry timestamp,
1567 and, if they do, it is recommended to ignore PAWS because
1568 "their cleanup function should take precedence over timestamps."
1569 Certainly, it is mistake. It is necessary to understand the reasons
1570 of this constraint to relax it: if peer reboots, clock may go
1571 out-of-sync and half-open connections will not be reset.
1572 Actually, the problem would be not existing if all
1573 the implementations followed draft about maintaining clock
1574 via reboots. Linux-2.2 DOES NOT!
1575
1576 However, we can relax time bounds for RST segments to MSL.
1577 */
1578 if (rst && !time_before32(ktime_get_seconds(),
1579 rx_opt->ts_recent_stamp + TCP_PAWS_MSL))
1580 return false;
1581 return true;
1582}
1583
1584bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
1585 int mib_idx, u32 *last_oow_ack_time);
1586
1587static inline void tcp_mib_init(struct net *net)
1588{
1589 /* See RFC 2012 */
1590 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1);
1591 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1592 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1593 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1);
1594}
1595
1596/* from STCP */
1597static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1598{
1599 tp->lost_skb_hint = NULL;
1600}
1601
1602static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1603{
1604 tcp_clear_retrans_hints_partial(tp);
1605 tp->retransmit_skb_hint = NULL;
1606}
1607
1608union tcp_md5_addr {
1609 struct in_addr a4;
1610#if IS_ENABLED(CONFIG_IPV6)
1611 struct in6_addr a6;
1612#endif
1613};
1614
1615/* - key database */
1616struct tcp_md5sig_key {
1617 struct hlist_node node;
1618 u8 keylen;
1619 u8 family; /* AF_INET or AF_INET6 */
1620 u8 prefixlen;
1621 u8 flags;
1622 union tcp_md5_addr addr;
1623 int l3index; /* set if key added with L3 scope */
1624 u8 key[TCP_MD5SIG_MAXKEYLEN];
1625 struct rcu_head rcu;
1626};
1627
1628/* - sock block */
1629struct tcp_md5sig_info {
1630 struct hlist_head head;
1631 struct rcu_head rcu;
1632};
1633
1634/* - pseudo header */
1635struct tcp4_pseudohdr {
1636 __be32 saddr;
1637 __be32 daddr;
1638 __u8 pad;
1639 __u8 protocol;
1640 __be16 len;
1641};
1642
1643struct tcp6_pseudohdr {
1644 struct in6_addr saddr;
1645 struct in6_addr daddr;
1646 __be32 len;
1647 __be32 protocol; /* including padding */
1648};
1649
1650union tcp_md5sum_block {
1651 struct tcp4_pseudohdr ip4;
1652#if IS_ENABLED(CONFIG_IPV6)
1653 struct tcp6_pseudohdr ip6;
1654#endif
1655};
1656
1657/* - pool: digest algorithm, hash description and scratch buffer */
1658struct tcp_md5sig_pool {
1659 struct ahash_request *md5_req;
1660 void *scratch;
1661};
1662
1663/* - functions */
1664int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1665 const struct sock *sk, const struct sk_buff *skb);
1666int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1667 int family, u8 prefixlen, int l3index, u8 flags,
1668 const u8 *newkey, u8 newkeylen, gfp_t gfp);
1669int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
1670 int family, u8 prefixlen, int l3index, u8 flags);
1671struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1672 const struct sock *addr_sk);
1673
1674#ifdef CONFIG_TCP_MD5SIG
1675#include <linux/jump_label.h>
1676extern struct static_key_false tcp_md5_needed;
1677struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1678 const union tcp_md5_addr *addr,
1679 int family);
1680static inline struct tcp_md5sig_key *
1681tcp_md5_do_lookup(const struct sock *sk, int l3index,
1682 const union tcp_md5_addr *addr, int family)
1683{
1684 if (!static_branch_unlikely(&tcp_md5_needed))
1685 return NULL;
1686 return __tcp_md5_do_lookup(sk, l3index, addr, family);
1687}
1688
1689enum skb_drop_reason
1690tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
1691 const void *saddr, const void *daddr,
1692 int family, int dif, int sdif);
1693
1694
1695#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
1696#else
1697static inline struct tcp_md5sig_key *
1698tcp_md5_do_lookup(const struct sock *sk, int l3index,
1699 const union tcp_md5_addr *addr, int family)
1700{
1701 return NULL;
1702}
1703
1704static inline enum skb_drop_reason
1705tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
1706 const void *saddr, const void *daddr,
1707 int family, int dif, int sdif)
1708{
1709 return SKB_NOT_DROPPED_YET;
1710}
1711#define tcp_twsk_md5_key(twsk) NULL
1712#endif
1713
1714bool tcp_alloc_md5sig_pool(void);
1715
1716struct tcp_md5sig_pool *tcp_get_md5sig_pool(void);
1717static inline void tcp_put_md5sig_pool(void)
1718{
1719 local_bh_enable();
1720}
1721
1722int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *,
1723 unsigned int header_len);
1724int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1725 const struct tcp_md5sig_key *key);
1726
1727/* From tcp_fastopen.c */
1728void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
1729 struct tcp_fastopen_cookie *cookie);
1730void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
1731 struct tcp_fastopen_cookie *cookie, bool syn_lost,
1732 u16 try_exp);
1733struct tcp_fastopen_request {
1734 /* Fast Open cookie. Size 0 means a cookie request */
1735 struct tcp_fastopen_cookie cookie;
1736 struct msghdr *data; /* data in MSG_FASTOPEN */
1737 size_t size;
1738 int copied; /* queued in tcp_connect() */
1739 struct ubuf_info *uarg;
1740};
1741void tcp_free_fastopen_req(struct tcp_sock *tp);
1742void tcp_fastopen_destroy_cipher(struct sock *sk);
1743void tcp_fastopen_ctx_destroy(struct net *net);
1744int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
1745 void *primary_key, void *backup_key);
1746int tcp_fastopen_get_cipher(struct net *net, struct inet_connection_sock *icsk,
1747 u64 *key);
1748void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
1749struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
1750 struct request_sock *req,
1751 struct tcp_fastopen_cookie *foc,
1752 const struct dst_entry *dst);
1753void tcp_fastopen_init_key_once(struct net *net);
1754bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
1755 struct tcp_fastopen_cookie *cookie);
1756bool tcp_fastopen_defer_connect(struct sock *sk, int *err);
1757#define TCP_FASTOPEN_KEY_LENGTH sizeof(siphash_key_t)
1758#define TCP_FASTOPEN_KEY_MAX 2
1759#define TCP_FASTOPEN_KEY_BUF_LENGTH \
1760 (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX)
1761
1762/* Fastopen key context */
1763struct tcp_fastopen_context {
1764 siphash_key_t key[TCP_FASTOPEN_KEY_MAX];
1765 int num;
1766 struct rcu_head rcu;
1767};
1768
1769void tcp_fastopen_active_disable(struct sock *sk);
1770bool tcp_fastopen_active_should_disable(struct sock *sk);
1771void tcp_fastopen_active_disable_ofo_check(struct sock *sk);
1772void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired);
1773
1774/* Caller needs to wrap with rcu_read_(un)lock() */
1775static inline
1776struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk)
1777{
1778 struct tcp_fastopen_context *ctx;
1779
1780 ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
1781 if (!ctx)
1782 ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
1783 return ctx;
1784}
1785
1786static inline
1787bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc,
1788 const struct tcp_fastopen_cookie *orig)
1789{
1790 if (orig->len == TCP_FASTOPEN_COOKIE_SIZE &&
1791 orig->len == foc->len &&
1792 !memcmp(orig->val, foc->val, foc->len))
1793 return true;
1794 return false;
1795}
1796
1797static inline
1798int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx)
1799{
1800 return ctx->num;
1801}
1802
1803/* Latencies incurred by various limits for a sender. They are
1804 * chronograph-like stats that are mutually exclusive.
1805 */
1806enum tcp_chrono {
1807 TCP_CHRONO_UNSPEC,
1808 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */
1809 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */
1810 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */
1811 __TCP_CHRONO_MAX,
1812};
1813
1814void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type);
1815void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type);
1816
1817/* This helper is needed, because skb->tcp_tsorted_anchor uses
1818 * the same memory storage than skb->destructor/_skb_refdst
1819 */
1820static inline void tcp_skb_tsorted_anchor_cleanup(struct sk_buff *skb)
1821{
1822 skb->destructor = NULL;
1823 skb->_skb_refdst = 0UL;
1824}
1825
1826#define tcp_skb_tsorted_save(skb) { \
1827 unsigned long _save = skb->_skb_refdst; \
1828 skb->_skb_refdst = 0UL;
1829
1830#define tcp_skb_tsorted_restore(skb) \
1831 skb->_skb_refdst = _save; \
1832}
1833
1834void tcp_write_queue_purge(struct sock *sk);
1835
1836static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk)
1837{
1838 return skb_rb_first(&sk->tcp_rtx_queue);
1839}
1840
1841static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk)
1842{
1843 return skb_rb_last(&sk->tcp_rtx_queue);
1844}
1845
1846static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk)
1847{
1848 return skb_peek_tail(&sk->sk_write_queue);
1849}
1850
1851#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1852 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1853
1854static inline struct sk_buff *tcp_send_head(const struct sock *sk)
1855{
1856 return skb_peek(&sk->sk_write_queue);
1857}
1858
1859static inline bool tcp_skb_is_last(const struct sock *sk,
1860 const struct sk_buff *skb)
1861{
1862 return skb_queue_is_last(&sk->sk_write_queue, skb);
1863}
1864
1865/**
1866 * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue
1867 * @sk: socket
1868 *
1869 * Since the write queue can have a temporary empty skb in it,
1870 * we must not use "return skb_queue_empty(&sk->sk_write_queue)"
1871 */
1872static inline bool tcp_write_queue_empty(const struct sock *sk)
1873{
1874 const struct tcp_sock *tp = tcp_sk(sk);
1875
1876 return tp->write_seq == tp->snd_nxt;
1877}
1878
1879static inline bool tcp_rtx_queue_empty(const struct sock *sk)
1880{
1881 return RB_EMPTY_ROOT(&sk->tcp_rtx_queue);
1882}
1883
1884static inline bool tcp_rtx_and_write_queues_empty(const struct sock *sk)
1885{
1886 return tcp_rtx_queue_empty(sk) && tcp_write_queue_empty(sk);
1887}
1888
1889static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1890{
1891 __skb_queue_tail(&sk->sk_write_queue, skb);
1892
1893 /* Queue it, remembering where we must start sending. */
1894 if (sk->sk_write_queue.next == skb)
1895 tcp_chrono_start(sk, TCP_CHRONO_BUSY);
1896}
1897
1898/* Insert new before skb on the write queue of sk. */
1899static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1900 struct sk_buff *skb,
1901 struct sock *sk)
1902{
1903 __skb_queue_before(&sk->sk_write_queue, skb, new);
1904}
1905
1906static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1907{
1908 tcp_skb_tsorted_anchor_cleanup(skb);
1909 __skb_unlink(skb, &sk->sk_write_queue);
1910}
1911
1912void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb);
1913
1914static inline void tcp_rtx_queue_unlink(struct sk_buff *skb, struct sock *sk)
1915{
1916 tcp_skb_tsorted_anchor_cleanup(skb);
1917 rb_erase(&skb->rbnode, &sk->tcp_rtx_queue);
1918}
1919
1920static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct sock *sk)
1921{
1922 list_del(&skb->tcp_tsorted_anchor);
1923 tcp_rtx_queue_unlink(skb, sk);
1924 tcp_wmem_free_skb(sk, skb);
1925}
1926
1927static inline void tcp_push_pending_frames(struct sock *sk)
1928{
1929 if (tcp_send_head(sk)) {
1930 struct tcp_sock *tp = tcp_sk(sk);
1931
1932 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
1933 }
1934}
1935
1936/* Start sequence of the skb just after the highest skb with SACKed
1937 * bit, valid only if sacked_out > 0 or when the caller has ensured
1938 * validity by itself.
1939 */
1940static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1941{
1942 if (!tp->sacked_out)
1943 return tp->snd_una;
1944
1945 if (tp->highest_sack == NULL)
1946 return tp->snd_nxt;
1947
1948 return TCP_SKB_CB(tp->highest_sack)->seq;
1949}
1950
1951static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1952{
1953 tcp_sk(sk)->highest_sack = skb_rb_next(skb);
1954}
1955
1956static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1957{
1958 return tcp_sk(sk)->highest_sack;
1959}
1960
1961static inline void tcp_highest_sack_reset(struct sock *sk)
1962{
1963 tcp_sk(sk)->highest_sack = tcp_rtx_queue_head(sk);
1964}
1965
1966/* Called when old skb is about to be deleted and replaced by new skb */
1967static inline void tcp_highest_sack_replace(struct sock *sk,
1968 struct sk_buff *old,
1969 struct sk_buff *new)
1970{
1971 if (old == tcp_highest_sack(sk))
1972 tcp_sk(sk)->highest_sack = new;
1973}
1974
1975/* This helper checks if socket has IP_TRANSPARENT set */
1976static inline bool inet_sk_transparent(const struct sock *sk)
1977{
1978 switch (sk->sk_state) {
1979 case TCP_TIME_WAIT:
1980 return inet_twsk(sk)->tw_transparent;
1981 case TCP_NEW_SYN_RECV:
1982 return inet_rsk(inet_reqsk(sk))->no_srccheck;
1983 }
1984 return inet_sk(sk)->transparent;
1985}
1986
1987/* Determines whether this is a thin stream (which may suffer from
1988 * increased latency). Used to trigger latency-reducing mechanisms.
1989 */
1990static inline bool tcp_stream_is_thin(struct tcp_sock *tp)
1991{
1992 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp);
1993}
1994
1995/* /proc */
1996enum tcp_seq_states {
1997 TCP_SEQ_STATE_LISTENING,
1998 TCP_SEQ_STATE_ESTABLISHED,
1999};
2000
2001void *tcp_seq_start(struct seq_file *seq, loff_t *pos);
2002void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
2003void tcp_seq_stop(struct seq_file *seq, void *v);
2004
2005struct tcp_seq_afinfo {
2006 sa_family_t family;
2007};
2008
2009struct tcp_iter_state {
2010 struct seq_net_private p;
2011 enum tcp_seq_states state;
2012 struct sock *syn_wait_sk;
2013 int bucket, offset, sbucket, num;
2014 loff_t last_pos;
2015};
2016
2017extern struct request_sock_ops tcp_request_sock_ops;
2018extern struct request_sock_ops tcp6_request_sock_ops;
2019
2020void tcp_v4_destroy_sock(struct sock *sk);
2021
2022struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
2023 netdev_features_t features);
2024struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb);
2025INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff));
2026INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb));
2027INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff));
2028INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb));
2029int tcp_gro_complete(struct sk_buff *skb);
2030
2031void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
2032
2033static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
2034{
2035 struct net *net = sock_net((struct sock *)tp);
2036 return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
2037}
2038
2039bool tcp_stream_memory_free(const struct sock *sk, int wake);
2040
2041#ifdef CONFIG_PROC_FS
2042int tcp4_proc_init(void);
2043void tcp4_proc_exit(void);
2044#endif
2045
2046int tcp_rtx_synack(const struct sock *sk, struct request_sock *req);
2047int tcp_conn_request(struct request_sock_ops *rsk_ops,
2048 const struct tcp_request_sock_ops *af_ops,
2049 struct sock *sk, struct sk_buff *skb);
2050
2051/* TCP af-specific functions */
2052struct tcp_sock_af_ops {
2053#ifdef CONFIG_TCP_MD5SIG
2054 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk,
2055 const struct sock *addr_sk);
2056 int (*calc_md5_hash)(char *location,
2057 const struct tcp_md5sig_key *md5,
2058 const struct sock *sk,
2059 const struct sk_buff *skb);
2060 int (*md5_parse)(struct sock *sk,
2061 int optname,
2062 sockptr_t optval,
2063 int optlen);
2064#endif
2065};
2066
2067struct tcp_request_sock_ops {
2068 u16 mss_clamp;
2069#ifdef CONFIG_TCP_MD5SIG
2070 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk,
2071 const struct sock *addr_sk);
2072 int (*calc_md5_hash) (char *location,
2073 const struct tcp_md5sig_key *md5,
2074 const struct sock *sk,
2075 const struct sk_buff *skb);
2076#endif
2077#ifdef CONFIG_SYN_COOKIES
2078 __u32 (*cookie_init_seq)(const struct sk_buff *skb,
2079 __u16 *mss);
2080#endif
2081 struct dst_entry *(*route_req)(const struct sock *sk,
2082 struct sk_buff *skb,
2083 struct flowi *fl,
2084 struct request_sock *req);
2085 u32 (*init_seq)(const struct sk_buff *skb);
2086 u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb);
2087 int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
2088 struct flowi *fl, struct request_sock *req,
2089 struct tcp_fastopen_cookie *foc,
2090 enum tcp_synack_type synack_type,
2091 struct sk_buff *syn_skb);
2092};
2093
2094extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops;
2095#if IS_ENABLED(CONFIG_IPV6)
2096extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops;
2097#endif
2098
2099#ifdef CONFIG_SYN_COOKIES
2100static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
2101 const struct sock *sk, struct sk_buff *skb,
2102 __u16 *mss)
2103{
2104 tcp_synq_overflow(sk);
2105 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);
2106 return ops->cookie_init_seq(skb, mss);
2107}
2108#else
2109static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
2110 const struct sock *sk, struct sk_buff *skb,
2111 __u16 *mss)
2112{
2113 return 0;
2114}
2115#endif
2116
2117int tcpv4_offload_init(void);
2118
2119void tcp_v4_init(void);
2120void tcp_init(void);
2121
2122/* tcp_recovery.c */
2123void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb);
2124void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced);
2125extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb,
2126 u32 reo_wnd);
2127extern bool tcp_rack_mark_lost(struct sock *sk);
2128extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
2129 u64 xmit_time);
2130extern void tcp_rack_reo_timeout(struct sock *sk);
2131extern void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs);
2132
2133/* At how many usecs into the future should the RTO fire? */
2134static inline s64 tcp_rto_delta_us(const struct sock *sk)
2135{
2136 const struct sk_buff *skb = tcp_rtx_queue_head(sk);
2137 u32 rto = inet_csk(sk)->icsk_rto;
2138 u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto);
2139
2140 return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;
2141}
2142
2143/*
2144 * Save and compile IPv4 options, return a pointer to it
2145 */
2146static inline struct ip_options_rcu *tcp_v4_save_options(struct net *net,
2147 struct sk_buff *skb)
2148{
2149 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt;
2150 struct ip_options_rcu *dopt = NULL;
2151
2152 if (opt->optlen) {
2153 int opt_size = sizeof(*dopt) + opt->optlen;
2154
2155 dopt = kmalloc(opt_size, GFP_ATOMIC);
2156 if (dopt && __ip_options_echo(net, &dopt->opt, skb, opt)) {
2157 kfree(dopt);
2158 dopt = NULL;
2159 }
2160 }
2161 return dopt;
2162}
2163
2164/* locally generated TCP pure ACKs have skb->truesize == 2
2165 * (check tcp_send_ack() in net/ipv4/tcp_output.c )
2166 * This is much faster than dissecting the packet to find out.
2167 * (Think of GRE encapsulations, IPv4, IPv6, ...)
2168 */
2169static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb)
2170{
2171 return skb->truesize == 2;
2172}
2173
2174static inline void skb_set_tcp_pure_ack(struct sk_buff *skb)
2175{
2176 skb->truesize = 2;
2177}
2178
2179static inline int tcp_inq(struct sock *sk)
2180{
2181 struct tcp_sock *tp = tcp_sk(sk);
2182 int answ;
2183
2184 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
2185 answ = 0;
2186 } else if (sock_flag(sk, SOCK_URGINLINE) ||
2187 !tp->urg_data ||
2188 before(tp->urg_seq, tp->copied_seq) ||
2189 !before(tp->urg_seq, tp->rcv_nxt)) {
2190
2191 answ = tp->rcv_nxt - tp->copied_seq;
2192
2193 /* Subtract 1, if FIN was received */
2194 if (answ && sock_flag(sk, SOCK_DONE))
2195 answ--;
2196 } else {
2197 answ = tp->urg_seq - tp->copied_seq;
2198 }
2199
2200 return answ;
2201}
2202
2203int tcp_peek_len(struct socket *sock);
2204
2205static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
2206{
2207 u16 segs_in;
2208
2209 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2210
2211 /* We update these fields while other threads might
2212 * read them from tcp_get_info()
2213 */
2214 WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in);
2215 if (skb->len > tcp_hdrlen(skb))
2216 WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in);
2217}
2218
2219/*
2220 * TCP listen path runs lockless.
2221 * We forced "struct sock" to be const qualified to make sure
2222 * we don't modify one of its field by mistake.
2223 * Here, we increment sk_drops which is an atomic_t, so we can safely
2224 * make sock writable again.
2225 */
2226static inline void tcp_listendrop(const struct sock *sk)
2227{
2228 atomic_inc(&((struct sock *)sk)->sk_drops);
2229 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
2230}
2231
2232enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer);
2233
2234/*
2235 * Interface for adding Upper Level Protocols over TCP
2236 */
2237
2238#define TCP_ULP_NAME_MAX 16
2239#define TCP_ULP_MAX 128
2240#define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX)
2241
2242struct tcp_ulp_ops {
2243 struct list_head list;
2244
2245 /* initialize ulp */
2246 int (*init)(struct sock *sk);
2247 /* update ulp */
2248 void (*update)(struct sock *sk, struct proto *p,
2249 void (*write_space)(struct sock *sk));
2250 /* cleanup ulp */
2251 void (*release)(struct sock *sk);
2252 /* diagnostic */
2253 int (*get_info)(const struct sock *sk, struct sk_buff *skb);
2254 size_t (*get_info_size)(const struct sock *sk);
2255 /* clone ulp */
2256 void (*clone)(const struct request_sock *req, struct sock *newsk,
2257 const gfp_t priority);
2258
2259 char name[TCP_ULP_NAME_MAX];
2260 struct module *owner;
2261};
2262int tcp_register_ulp(struct tcp_ulp_ops *type);
2263void tcp_unregister_ulp(struct tcp_ulp_ops *type);
2264int tcp_set_ulp(struct sock *sk, const char *name);
2265void tcp_get_available_ulp(char *buf, size_t len);
2266void tcp_cleanup_ulp(struct sock *sk);
2267void tcp_update_ulp(struct sock *sk, struct proto *p,
2268 void (*write_space)(struct sock *sk));
2269
2270#define MODULE_ALIAS_TCP_ULP(name) \
2271 __MODULE_INFO(alias, alias_userspace, name); \
2272 __MODULE_INFO(alias, alias_tcp_ulp, "tcp-ulp-" name)
2273
2274#ifdef CONFIG_NET_SOCK_MSG
2275struct sk_msg;
2276struct sk_psock;
2277
2278#ifdef CONFIG_BPF_SYSCALL
2279struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
2280int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
2281void tcp_bpf_clone(const struct sock *sk, struct sock *newsk);
2282#endif /* CONFIG_BPF_SYSCALL */
2283
2284int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, u32 bytes,
2285 int flags);
2286#endif /* CONFIG_NET_SOCK_MSG */
2287
2288#if !defined(CONFIG_BPF_SYSCALL) || !defined(CONFIG_NET_SOCK_MSG)
2289static inline void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
2290{
2291}
2292#endif
2293
2294#ifdef CONFIG_CGROUP_BPF
2295static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
2296 struct sk_buff *skb,
2297 unsigned int end_offset)
2298{
2299 skops->skb = skb;
2300 skops->skb_data_end = skb->data + end_offset;
2301}
2302#else
2303static inline void bpf_skops_init_skb(struct bpf_sock_ops_kern *skops,
2304 struct sk_buff *skb,
2305 unsigned int end_offset)
2306{
2307}
2308#endif
2309
2310/* Call BPF_SOCK_OPS program that returns an int. If the return value
2311 * is < 0, then the BPF op failed (for example if the loaded BPF
2312 * program does not support the chosen operation or there is no BPF
2313 * program loaded).
2314 */
2315#ifdef CONFIG_BPF
2316static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
2317{
2318 struct bpf_sock_ops_kern sock_ops;
2319 int ret;
2320
2321 memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
2322 if (sk_fullsock(sk)) {
2323 sock_ops.is_fullsock = 1;
2324 sock_owned_by_me(sk);
2325 }
2326
2327 sock_ops.sk = sk;
2328 sock_ops.op = op;
2329 if (nargs > 0)
2330 memcpy(sock_ops.args, args, nargs * sizeof(*args));
2331
2332 ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);
2333 if (ret == 0)
2334 ret = sock_ops.reply;
2335 else
2336 ret = -1;
2337 return ret;
2338}
2339
2340static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
2341{
2342 u32 args[2] = {arg1, arg2};
2343
2344 return tcp_call_bpf(sk, op, 2, args);
2345}
2346
2347static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
2348 u32 arg3)
2349{
2350 u32 args[3] = {arg1, arg2, arg3};
2351
2352 return tcp_call_bpf(sk, op, 3, args);
2353}
2354
2355#else
2356static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
2357{
2358 return -EPERM;
2359}
2360
2361static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
2362{
2363 return -EPERM;
2364}
2365
2366static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
2367 u32 arg3)
2368{
2369 return -EPERM;
2370}
2371
2372#endif
2373
2374static inline u32 tcp_timeout_init(struct sock *sk)
2375{
2376 int timeout;
2377
2378 timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL);
2379
2380 if (timeout <= 0)
2381 timeout = TCP_TIMEOUT_INIT;
2382 return min_t(int, timeout, TCP_RTO_MAX);
2383}
2384
2385static inline u32 tcp_rwnd_init_bpf(struct sock *sk)
2386{
2387 int rwnd;
2388
2389 rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL);
2390
2391 if (rwnd < 0)
2392 rwnd = 0;
2393 return rwnd;
2394}
2395
2396static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk)
2397{
2398 return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);
2399}
2400
2401static inline void tcp_bpf_rtt(struct sock *sk)
2402{
2403 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_RTT_CB_FLAG))
2404 tcp_call_bpf(sk, BPF_SOCK_OPS_RTT_CB, 0, NULL);
2405}
2406
2407#if IS_ENABLED(CONFIG_SMC)
2408extern struct static_key_false tcp_have_smc;
2409#endif
2410
2411#if IS_ENABLED(CONFIG_TLS_DEVICE)
2412void clean_acked_data_enable(struct inet_connection_sock *icsk,
2413 void (*cad)(struct sock *sk, u32 ack_seq));
2414void clean_acked_data_disable(struct inet_connection_sock *icsk);
2415void clean_acked_data_flush(void);
2416#endif
2417
2418DECLARE_STATIC_KEY_FALSE(tcp_tx_delay_enabled);
2419static inline void tcp_add_tx_delay(struct sk_buff *skb,
2420 const struct tcp_sock *tp)
2421{
2422 if (static_branch_unlikely(&tcp_tx_delay_enabled))
2423 skb->skb_mstamp_ns += (u64)tp->tcp_tx_delay * NSEC_PER_USEC;
2424}
2425
2426/* Compute Earliest Departure Time for some control packets
2427 * like ACK or RST for TIME_WAIT or non ESTABLISHED sockets.
2428 */
2429static inline u64 tcp_transmit_time(const struct sock *sk)
2430{
2431 if (static_branch_unlikely(&tcp_tx_delay_enabled)) {
2432 u32 delay = (sk->sk_state == TCP_TIME_WAIT) ?
2433 tcp_twsk(sk)->tw_tx_delay : tcp_sk(sk)->tcp_tx_delay;
2434
2435 return tcp_clock_ns() + (u64)delay * NSEC_PER_USEC;
2436 }
2437 return 0;
2438}
2439
2440#endif /* _TCP_H */
2441

source code of linux/include/net/tcp.h