1/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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 protocol.
8 *
9 * Version: @(#)tcp.h 1.0.2 04/28/93
10 *
11 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18#ifndef _UAPI_LINUX_TCP_H
19#define _UAPI_LINUX_TCP_H
20
21#include <linux/types.h>
22#include <asm/byteorder.h>
23#include <linux/socket.h>
24
25struct tcphdr {
26 __be16 source;
27 __be16 dest;
28 __be32 seq;
29 __be32 ack_seq;
30#if defined(__LITTLE_ENDIAN_BITFIELD)
31 __u16 res1:4,
32 doff:4,
33 fin:1,
34 syn:1,
35 rst:1,
36 psh:1,
37 ack:1,
38 urg:1,
39 ece:1,
40 cwr:1;
41#elif defined(__BIG_ENDIAN_BITFIELD)
42 __u16 doff:4,
43 res1:4,
44 cwr:1,
45 ece:1,
46 urg:1,
47 ack:1,
48 psh:1,
49 rst:1,
50 syn:1,
51 fin:1;
52#else
53#error "Adjust your <asm/byteorder.h> defines"
54#endif
55 __be16 window;
56 __sum16 check;
57 __be16 urg_ptr;
58};
59
60/*
61 * The union cast uses a gcc extension to avoid aliasing problems
62 * (union is compatible to any of its members)
63 * This means this part of the code is -fstrict-aliasing safe now.
64 */
65union tcp_word_hdr {
66 struct tcphdr hdr;
67 __be32 words[5];
68};
69
70#define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])
71
72enum {
73 TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000),
74 TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000),
75 TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000),
76 TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000),
77 TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000),
78 TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000),
79 TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000),
80 TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000),
81 TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000),
82 TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000)
83};
84
85/*
86 * TCP general constants
87 */
88#define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */
89#define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */
90
91/* TCP socket options */
92#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
93#define TCP_MAXSEG 2 /* Limit MSS */
94#define TCP_CORK 3 /* Never send partially complete segments */
95#define TCP_KEEPIDLE 4 /* Start keeplives after this period */
96#define TCP_KEEPINTVL 5 /* Interval between keepalives */
97#define TCP_KEEPCNT 6 /* Number of keepalives before death */
98#define TCP_SYNCNT 7 /* Number of SYN retransmits */
99#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
100#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
101#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
102#define TCP_INFO 11 /* Information about this connection. */
103#define TCP_QUICKACK 12 /* Block/reenable quick acks */
104#define TCP_CONGESTION 13 /* Congestion control algorithm */
105#define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */
106#define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/
107#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */
108#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */
109#define TCP_REPAIR 19 /* TCP sock is under repair right now */
110#define TCP_REPAIR_QUEUE 20
111#define TCP_QUEUE_SEQ 21
112#define TCP_REPAIR_OPTIONS 22
113#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */
114#define TCP_TIMESTAMP 24
115#define TCP_NOTSENT_LOWAT 25 /* limit number of unsent bytes in write queue */
116#define TCP_CC_INFO 26 /* Get Congestion Control (optional) info */
117#define TCP_SAVE_SYN 27 /* Record SYN headers for new connections */
118#define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */
119#define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */
120#define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */
121#define TCP_ULP 31 /* Attach a ULP to a TCP connection */
122#define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with extensions */
123#define TCP_FASTOPEN_KEY 33 /* Set the key for Fast Open (cookie) */
124#define TCP_FASTOPEN_NO_COOKIE 34 /* Enable TFO without a TFO cookie */
125#define TCP_ZEROCOPY_RECEIVE 35
126#define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */
127
128#define TCP_CM_INQ TCP_INQ
129
130#define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */
131
132#define TCP_AO_ADD_KEY 38 /* Add/Set MKT */
133#define TCP_AO_DEL_KEY 39 /* Delete MKT */
134#define TCP_AO_INFO 40 /* Set/list TCP-AO per-socket options */
135#define TCP_AO_GET_KEYS 41 /* List MKT(s) */
136#define TCP_AO_REPAIR 42 /* Get/Set SNEs and ISNs */
137
138#define TCP_REPAIR_ON 1
139#define TCP_REPAIR_OFF 0
140#define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
141
142struct tcp_repair_opt {
143 __u32 opt_code;
144 __u32 opt_val;
145};
146
147struct tcp_repair_window {
148 __u32 snd_wl1;
149 __u32 snd_wnd;
150 __u32 max_window;
151
152 __u32 rcv_wnd;
153 __u32 rcv_wup;
154};
155
156enum {
157 TCP_NO_QUEUE,
158 TCP_RECV_QUEUE,
159 TCP_SEND_QUEUE,
160 TCP_QUEUES_NR,
161};
162
163/* why fastopen failed from client perspective */
164enum tcp_fastopen_client_fail {
165 TFO_STATUS_UNSPEC, /* catch-all */
166 TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
167 TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
168 TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
169};
170
171/* for TCP_INFO socket option */
172#define TCPI_OPT_TIMESTAMPS 1
173#define TCPI_OPT_SACK 2
174#define TCPI_OPT_WSCALE 4
175#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */
176#define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */
177#define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */
178#define TCPI_OPT_USEC_TS 64 /* usec timestamps */
179
180/*
181 * Sender's congestion state indicating normal or abnormal situations
182 * in the last round of packets sent. The state is driven by the ACK
183 * information and timer events.
184 */
185enum tcp_ca_state {
186 /*
187 * Nothing bad has been observed recently.
188 * No apparent reordering, packet loss, or ECN marks.
189 */
190 TCP_CA_Open = 0,
191#define TCPF_CA_Open (1<<TCP_CA_Open)
192 /*
193 * The sender enters disordered state when it has received DUPACKs or
194 * SACKs in the last round of packets sent. This could be due to packet
195 * loss or reordering but needs further information to confirm packets
196 * have been lost.
197 */
198 TCP_CA_Disorder = 1,
199#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
200 /*
201 * The sender enters Congestion Window Reduction (CWR) state when it
202 * has received ACKs with ECN-ECE marks, or has experienced congestion
203 * or packet discard on the sender host (e.g. qdisc).
204 */
205 TCP_CA_CWR = 2,
206#define TCPF_CA_CWR (1<<TCP_CA_CWR)
207 /*
208 * The sender is in fast recovery and retransmitting lost packets,
209 * typically triggered by ACK events.
210 */
211 TCP_CA_Recovery = 3,
212#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
213 /*
214 * The sender is in loss recovery triggered by retransmission timeout.
215 */
216 TCP_CA_Loss = 4
217#define TCPF_CA_Loss (1<<TCP_CA_Loss)
218};
219
220struct tcp_info {
221 __u8 tcpi_state;
222 __u8 tcpi_ca_state;
223 __u8 tcpi_retransmits;
224 __u8 tcpi_probes;
225 __u8 tcpi_backoff;
226 __u8 tcpi_options;
227 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
228 __u8 tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
229
230 __u32 tcpi_rto;
231 __u32 tcpi_ato;
232 __u32 tcpi_snd_mss;
233 __u32 tcpi_rcv_mss;
234
235 __u32 tcpi_unacked;
236 __u32 tcpi_sacked;
237 __u32 tcpi_lost;
238 __u32 tcpi_retrans;
239 __u32 tcpi_fackets;
240
241 /* Times. */
242 __u32 tcpi_last_data_sent;
243 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
244 __u32 tcpi_last_data_recv;
245 __u32 tcpi_last_ack_recv;
246
247 /* Metrics. */
248 __u32 tcpi_pmtu;
249 __u32 tcpi_rcv_ssthresh;
250 __u32 tcpi_rtt;
251 __u32 tcpi_rttvar;
252 __u32 tcpi_snd_ssthresh;
253 __u32 tcpi_snd_cwnd;
254 __u32 tcpi_advmss;
255 __u32 tcpi_reordering;
256
257 __u32 tcpi_rcv_rtt;
258 __u32 tcpi_rcv_space;
259
260 __u32 tcpi_total_retrans;
261
262 __u64 tcpi_pacing_rate;
263 __u64 tcpi_max_pacing_rate;
264 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
265 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
266 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
267 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */
268
269 __u32 tcpi_notsent_bytes;
270 __u32 tcpi_min_rtt;
271 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
272 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
273
274 __u64 tcpi_delivery_rate;
275
276 __u64 tcpi_busy_time; /* Time (usec) busy sending data */
277 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
278 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
279
280 __u32 tcpi_delivered;
281 __u32 tcpi_delivered_ce;
282
283 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
284 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
285 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */
286 __u32 tcpi_reord_seen; /* reordering events seen */
287
288 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */
289
290 __u32 tcpi_snd_wnd; /* peer's advertised receive window after
291 * scaling (bytes)
292 */
293 __u32 tcpi_rcv_wnd; /* local advertised receive window after
294 * scaling (bytes)
295 */
296
297 __u32 tcpi_rehash; /* PLB or timeout triggered rehash attempts */
298
299 __u16 tcpi_total_rto; /* Total number of RTO timeouts, including
300 * SYN/SYN-ACK and recurring timeouts.
301 */
302 __u16 tcpi_total_rto_recoveries; /* Total number of RTO
303 * recoveries, including any
304 * unfinished recovery.
305 */
306 __u32 tcpi_total_rto_time; /* Total time spent in RTO recoveries
307 * in milliseconds, including any
308 * unfinished recovery.
309 */
310};
311
312/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
313enum {
314 TCP_NLA_PAD,
315 TCP_NLA_BUSY, /* Time (usec) busy sending data */
316 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
317 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
318 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
319 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
320 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
321 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
322 TCP_NLA_SND_CWND, /* Sending congestion window */
323 TCP_NLA_REORDERING, /* Reordering metric */
324 TCP_NLA_MIN_RTT, /* minimum RTT */
325 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
326 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
327 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
328 TCP_NLA_CA_STATE, /* ca_state of socket */
329 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
330 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
331 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
332 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
333 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */
334 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */
335 TCP_NLA_REORD_SEEN, /* reordering events seen */
336 TCP_NLA_SRTT, /* smoothed RTT in usecs */
337 TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
338 TCP_NLA_BYTES_NOTSENT, /* Bytes in write queue not yet sent */
339 TCP_NLA_EDT, /* Earliest departure time (CLOCK_MONOTONIC) */
340 TCP_NLA_TTL, /* TTL or hop limit of a packet received */
341 TCP_NLA_REHASH, /* PLB and timeout triggered rehash attempts */
342};
343
344/* for TCP_MD5SIG socket option */
345#define TCP_MD5SIG_MAXKEYLEN 80
346
347/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
348#define TCP_MD5SIG_FLAG_PREFIX 0x1 /* address prefix length */
349#define TCP_MD5SIG_FLAG_IFINDEX 0x2 /* ifindex set */
350
351struct tcp_md5sig {
352 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
353 __u8 tcpm_flags; /* extension flags */
354 __u8 tcpm_prefixlen; /* address prefix */
355 __u16 tcpm_keylen; /* key length */
356 int tcpm_ifindex; /* device index for scope */
357 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
358};
359
360/* INET_DIAG_MD5SIG */
361struct tcp_diag_md5sig {
362 __u8 tcpm_family;
363 __u8 tcpm_prefixlen;
364 __u16 tcpm_keylen;
365 __be32 tcpm_addr[4];
366 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
367};
368
369#define TCP_AO_MAXKEYLEN 80
370
371#define TCP_AO_KEYF_IFINDEX (1 << 0) /* L3 ifindex for VRF */
372#define TCP_AO_KEYF_EXCLUDE_OPT (1 << 1) /* "Indicates whether TCP
373 * options other than TCP-AO
374 * are included in the MAC
375 * calculation"
376 */
377
378struct tcp_ao_add { /* setsockopt(TCP_AO_ADD_KEY) */
379 struct __kernel_sockaddr_storage addr; /* peer's address for the key */
380 char alg_name[64]; /* crypto hash algorithm to use */
381 __s32 ifindex; /* L3 dev index for VRF */
382 __u32 set_current :1, /* set key as Current_key at once */
383 set_rnext :1, /* request it from peer with RNext_key */
384 reserved :30; /* must be 0 */
385 __u16 reserved2; /* padding, must be 0 */
386 __u8 prefix; /* peer's address prefix */
387 __u8 sndid; /* SendID for outgoing segments */
388 __u8 rcvid; /* RecvID to match for incoming seg */
389 __u8 maclen; /* length of authentication code (hash) */
390 __u8 keyflags; /* see TCP_AO_KEYF_ */
391 __u8 keylen; /* length of ::key */
392 __u8 key[TCP_AO_MAXKEYLEN];
393} __attribute__((aligned(8)));
394
395struct tcp_ao_del { /* setsockopt(TCP_AO_DEL_KEY) */
396 struct __kernel_sockaddr_storage addr; /* peer's address for the key */
397 __s32 ifindex; /* L3 dev index for VRF */
398 __u32 set_current :1, /* corresponding ::current_key */
399 set_rnext :1, /* corresponding ::rnext */
400 del_async :1, /* only valid for listen sockets */
401 reserved :29; /* must be 0 */
402 __u16 reserved2; /* padding, must be 0 */
403 __u8 prefix; /* peer's address prefix */
404 __u8 sndid; /* SendID for outgoing segments */
405 __u8 rcvid; /* RecvID to match for incoming seg */
406 __u8 current_key; /* KeyID to set as Current_key */
407 __u8 rnext; /* KeyID to set as Rnext_key */
408 __u8 keyflags; /* see TCP_AO_KEYF_ */
409} __attribute__((aligned(8)));
410
411struct tcp_ao_info_opt { /* setsockopt(TCP_AO_INFO), getsockopt(TCP_AO_INFO) */
412 /* Here 'in' is for setsockopt(), 'out' is for getsockopt() */
413 __u32 set_current :1, /* in/out: corresponding ::current_key */
414 set_rnext :1, /* in/out: corresponding ::rnext */
415 ao_required :1, /* in/out: don't accept non-AO connects */
416 set_counters :1, /* in: set/clear ::pkt_* counters */
417 accept_icmps :1, /* in/out: accept incoming ICMPs */
418 reserved :27; /* must be 0 */
419 __u16 reserved2; /* padding, must be 0 */
420 __u8 current_key; /* in/out: KeyID of Current_key */
421 __u8 rnext; /* in/out: keyid of RNext_key */
422 __u64 pkt_good; /* in/out: verified segments */
423 __u64 pkt_bad; /* in/out: failed verification */
424 __u64 pkt_key_not_found; /* in/out: could not find a key to verify */
425 __u64 pkt_ao_required; /* in/out: segments missing TCP-AO sign */
426 __u64 pkt_dropped_icmp; /* in/out: ICMPs that were ignored */
427} __attribute__((aligned(8)));
428
429struct tcp_ao_getsockopt { /* getsockopt(TCP_AO_GET_KEYS) */
430 struct __kernel_sockaddr_storage addr; /* in/out: dump keys for peer
431 * with this address/prefix
432 */
433 char alg_name[64]; /* out: crypto hash algorithm */
434 __u8 key[TCP_AO_MAXKEYLEN];
435 __u32 nkeys; /* in: size of the userspace buffer
436 * @optval, measured in @optlen - the
437 * sizeof(struct tcp_ao_getsockopt)
438 * out: number of keys that matched
439 */
440 __u16 is_current :1, /* in: match and dump Current_key,
441 * out: the dumped key is Current_key
442 */
443
444 is_rnext :1, /* in: match and dump RNext_key,
445 * out: the dumped key is RNext_key
446 */
447 get_all :1, /* in: dump all keys */
448 reserved :13; /* padding, must be 0 */
449 __u8 sndid; /* in/out: dump keys with SendID */
450 __u8 rcvid; /* in/out: dump keys with RecvID */
451 __u8 prefix; /* in/out: dump keys with address/prefix */
452 __u8 maclen; /* out: key's length of authentication
453 * code (hash)
454 */
455 __u8 keyflags; /* in/out: see TCP_AO_KEYF_ */
456 __u8 keylen; /* out: length of ::key */
457 __s32 ifindex; /* in/out: L3 dev index for VRF */
458 __u64 pkt_good; /* out: verified segments */
459 __u64 pkt_bad; /* out: segments that failed verification */
460} __attribute__((aligned(8)));
461
462struct tcp_ao_repair { /* {s,g}etsockopt(TCP_AO_REPAIR) */
463 __be32 snt_isn;
464 __be32 rcv_isn;
465 __u32 snd_sne;
466 __u32 rcv_sne;
467} __attribute__((aligned(8)));
468
469/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
470
471#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
472struct tcp_zerocopy_receive {
473 __u64 address; /* in: address of mapping */
474 __u32 length; /* in/out: number of bytes to map/mapped */
475 __u32 recv_skip_hint; /* out: amount of bytes to skip */
476 __u32 inq; /* out: amount of bytes in read queue */
477 __s32 err; /* out: socket error */
478 __u64 copybuf_address; /* in: copybuf address (small reads) */
479 __s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
480 __u32 flags; /* in: flags */
481 __u64 msg_control; /* ancillary data */
482 __u64 msg_controllen;
483 __u32 msg_flags;
484 __u32 reserved; /* set to 0 for now */
485};
486#endif /* _UAPI_LINUX_TCP_H */
487

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