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
25 struct 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 */
65 union 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
72 enum {
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_IS_MPTCP 43 /* Is MPTCP being used? */
139
140 #define TCP_REPAIR_ON 1
141 #define TCP_REPAIR_OFF 0
142 #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
143
144 struct tcp_repair_opt {
145 __u32 opt_code;
146 __u32 opt_val;
147 };
148
149 struct tcp_repair_window {
150 __u32 snd_wl1;
151 __u32 snd_wnd;
152 __u32 max_window;
153
154 __u32 rcv_wnd;
155 __u32 rcv_wup;
156 };
157
158 enum {
159 TCP_NO_QUEUE,
160 TCP_RECV_QUEUE,
161 TCP_SEND_QUEUE,
162 TCP_QUEUES_NR,
163 };
164
165 /* why fastopen failed from client perspective */
166 enum tcp_fastopen_client_fail {
167 TFO_STATUS_UNSPEC, /* catch-all */
168 TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
169 TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
170 TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
171 };
172
173 /* for TCP_INFO socket option */
174 #define TCPI_OPT_TIMESTAMPS 1
175 #define TCPI_OPT_SACK 2
176 #define TCPI_OPT_WSCALE 4
177 #define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */
178 #define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */
179 #define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */
180 #define TCPI_OPT_USEC_TS 64 /* usec timestamps */
181
182 /*
183 * Sender's congestion state indicating normal or abnormal situations
184 * in the last round of packets sent. The state is driven by the ACK
185 * information and timer events.
186 */
187 enum tcp_ca_state {
188 /*
189 * Nothing bad has been observed recently.
190 * No apparent reordering, packet loss, or ECN marks.
191 */
192 TCP_CA_Open = 0,
193 #define TCPF_CA_Open (1<<TCP_CA_Open)
194 /*
195 * The sender enters disordered state when it has received DUPACKs or
196 * SACKs in the last round of packets sent. This could be due to packet
197 * loss or reordering but needs further information to confirm packets
198 * have been lost.
199 */
200 TCP_CA_Disorder = 1,
201 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
202 /*
203 * The sender enters Congestion Window Reduction (CWR) state when it
204 * has received ACKs with ECN-ECE marks, or has experienced congestion
205 * or packet discard on the sender host (e.g. qdisc).
206 */
207 TCP_CA_CWR = 2,
208 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
209 /*
210 * The sender is in fast recovery and retransmitting lost packets,
211 * typically triggered by ACK events.
212 */
213 TCP_CA_Recovery = 3,
214 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
215 /*
216 * The sender is in loss recovery triggered by retransmission timeout.
217 */
218 TCP_CA_Loss = 4
219 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
220 };
221
222 struct tcp_info {
223 __u8 tcpi_state;
224 __u8 tcpi_ca_state;
225 __u8 tcpi_retransmits;
226 __u8 tcpi_probes;
227 __u8 tcpi_backoff;
228 __u8 tcpi_options;
229 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
230 __u8 tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
231
232 __u32 tcpi_rto;
233 __u32 tcpi_ato;
234 __u32 tcpi_snd_mss;
235 __u32 tcpi_rcv_mss;
236
237 __u32 tcpi_unacked;
238 __u32 tcpi_sacked;
239 __u32 tcpi_lost;
240 __u32 tcpi_retrans;
241 __u32 tcpi_fackets;
242
243 /* Times. */
244 __u32 tcpi_last_data_sent;
245 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
246 __u32 tcpi_last_data_recv;
247 __u32 tcpi_last_ack_recv;
248
249 /* Metrics. */
250 __u32 tcpi_pmtu;
251 __u32 tcpi_rcv_ssthresh;
252 __u32 tcpi_rtt;
253 __u32 tcpi_rttvar;
254 __u32 tcpi_snd_ssthresh;
255 __u32 tcpi_snd_cwnd;
256 __u32 tcpi_advmss;
257 __u32 tcpi_reordering;
258
259 __u32 tcpi_rcv_rtt;
260 __u32 tcpi_rcv_space;
261
262 __u32 tcpi_total_retrans;
263
264 __u64 tcpi_pacing_rate;
265 __u64 tcpi_max_pacing_rate;
266 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
267 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
268 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
269 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */
270
271 __u32 tcpi_notsent_bytes;
272 __u32 tcpi_min_rtt;
273 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
274 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
275
276 __u64 tcpi_delivery_rate;
277
278 __u64 tcpi_busy_time; /* Time (usec) busy sending data */
279 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
280 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
281
282 __u32 tcpi_delivered;
283 __u32 tcpi_delivered_ce;
284
285 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
286 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
287 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */
288 __u32 tcpi_reord_seen; /* reordering events seen */
289
290 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */
291
292 __u32 tcpi_snd_wnd; /* peer's advertised receive window after
293 * scaling (bytes)
294 */
295 __u32 tcpi_rcv_wnd; /* local advertised receive window after
296 * scaling (bytes)
297 */
298
299 __u32 tcpi_rehash; /* PLB or timeout triggered rehash attempts */
300
301 __u16 tcpi_total_rto; /* Total number of RTO timeouts, including
302 * SYN/SYN-ACK and recurring timeouts.
303 */
304 __u16 tcpi_total_rto_recoveries; /* Total number of RTO
305 * recoveries, including any
306 * unfinished recovery.
307 */
308 __u32 tcpi_total_rto_time; /* Total time spent in RTO recoveries
309 * in milliseconds, including any
310 * unfinished recovery.
311 */
312 };
313
314 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
315 enum {
316 TCP_NLA_PAD,
317 TCP_NLA_BUSY, /* Time (usec) busy sending data */
318 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
319 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
320 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
321 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
322 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
323 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
324 TCP_NLA_SND_CWND, /* Sending congestion window */
325 TCP_NLA_REORDERING, /* Reordering metric */
326 TCP_NLA_MIN_RTT, /* minimum RTT */
327 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
328 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
329 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
330 TCP_NLA_CA_STATE, /* ca_state of socket */
331 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
332 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
333 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
334 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
335 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */
336 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */
337 TCP_NLA_REORD_SEEN, /* reordering events seen */
338 TCP_NLA_SRTT, /* smoothed RTT in usecs */
339 TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
340 TCP_NLA_BYTES_NOTSENT, /* Bytes in write queue not yet sent */
341 TCP_NLA_EDT, /* Earliest departure time (CLOCK_MONOTONIC) */
342 TCP_NLA_TTL, /* TTL or hop limit of a packet received */
343 TCP_NLA_REHASH, /* PLB and timeout triggered rehash attempts */
344 };
345
346 /* for TCP_MD5SIG socket option */
347 #define TCP_MD5SIG_MAXKEYLEN 80
348
349 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
350 #define TCP_MD5SIG_FLAG_PREFIX 0x1 /* address prefix length */
351 #define TCP_MD5SIG_FLAG_IFINDEX 0x2 /* ifindex set */
352
353 struct tcp_md5sig {
354 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
355 __u8 tcpm_flags; /* extension flags */
356 __u8 tcpm_prefixlen; /* address prefix */
357 __u16 tcpm_keylen; /* key length */
358 int tcpm_ifindex; /* device index for scope */
359 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
360 };
361
362 /* INET_DIAG_MD5SIG */
363 struct tcp_diag_md5sig {
364 __u8 tcpm_family;
365 __u8 tcpm_prefixlen;
366 __u16 tcpm_keylen;
367 __be32 tcpm_addr[4];
368 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
369 };
370
371 #define TCP_AO_MAXKEYLEN 80
372
373 #define TCP_AO_KEYF_IFINDEX (1 << 0) /* L3 ifindex for VRF */
374 #define TCP_AO_KEYF_EXCLUDE_OPT (1 << 1) /* "Indicates whether TCP
375 * options other than TCP-AO
376 * are included in the MAC
377 * calculation"
378 */
379
380 struct tcp_ao_add { /* setsockopt(TCP_AO_ADD_KEY) */
381 struct __kernel_sockaddr_storage addr; /* peer's address for the key */
382 char alg_name[64]; /* crypto hash algorithm to use */
383 __s32 ifindex; /* L3 dev index for VRF */
384 __u32 set_current :1, /* set key as Current_key at once */
385 set_rnext :1, /* request it from peer with RNext_key */
386 reserved :30; /* must be 0 */
387 __u16 reserved2; /* padding, must be 0 */
388 __u8 prefix; /* peer's address prefix */
389 __u8 sndid; /* SendID for outgoing segments */
390 __u8 rcvid; /* RecvID to match for incoming seg */
391 __u8 maclen; /* length of authentication code (hash) */
392 __u8 keyflags; /* see TCP_AO_KEYF_ */
393 __u8 keylen; /* length of ::key */
394 __u8 key[TCP_AO_MAXKEYLEN];
395 } __attribute__((aligned(8)));
396
397 struct tcp_ao_del { /* setsockopt(TCP_AO_DEL_KEY) */
398 struct __kernel_sockaddr_storage addr; /* peer's address for the key */
399 __s32 ifindex; /* L3 dev index for VRF */
400 __u32 set_current :1, /* corresponding ::current_key */
401 set_rnext :1, /* corresponding ::rnext */
402 del_async :1, /* only valid for listen sockets */
403 reserved :29; /* must be 0 */
404 __u16 reserved2; /* padding, must be 0 */
405 __u8 prefix; /* peer's address prefix */
406 __u8 sndid; /* SendID for outgoing segments */
407 __u8 rcvid; /* RecvID to match for incoming seg */
408 __u8 current_key; /* KeyID to set as Current_key */
409 __u8 rnext; /* KeyID to set as Rnext_key */
410 __u8 keyflags; /* see TCP_AO_KEYF_ */
411 } __attribute__((aligned(8)));
412
413 struct tcp_ao_info_opt { /* setsockopt(TCP_AO_INFO), getsockopt(TCP_AO_INFO) */
414 /* Here 'in' is for setsockopt(), 'out' is for getsockopt() */
415 __u32 set_current :1, /* in/out: corresponding ::current_key */
416 set_rnext :1, /* in/out: corresponding ::rnext */
417 ao_required :1, /* in/out: don't accept non-AO connects */
418 set_counters :1, /* in: set/clear ::pkt_* counters */
419 accept_icmps :1, /* in/out: accept incoming ICMPs */
420 reserved :27; /* must be 0 */
421 __u16 reserved2; /* padding, must be 0 */
422 __u8 current_key; /* in/out: KeyID of Current_key */
423 __u8 rnext; /* in/out: keyid of RNext_key */
424 __u64 pkt_good; /* in/out: verified segments */
425 __u64 pkt_bad; /* in/out: failed verification */
426 __u64 pkt_key_not_found; /* in/out: could not find a key to verify */
427 __u64 pkt_ao_required; /* in/out: segments missing TCP-AO sign */
428 __u64 pkt_dropped_icmp; /* in/out: ICMPs that were ignored */
429 } __attribute__((aligned(8)));
430
431 struct tcp_ao_getsockopt { /* getsockopt(TCP_AO_GET_KEYS) */
432 struct __kernel_sockaddr_storage addr; /* in/out: dump keys for peer
433 * with this address/prefix
434 */
435 char alg_name[64]; /* out: crypto hash algorithm */
436 __u8 key[TCP_AO_MAXKEYLEN];
437 __u32 nkeys; /* in: size of the userspace buffer
438 * @optval, measured in @optlen - the
439 * sizeof(struct tcp_ao_getsockopt)
440 * out: number of keys that matched
441 */
442 __u16 is_current :1, /* in: match and dump Current_key,
443 * out: the dumped key is Current_key
444 */
445
446 is_rnext :1, /* in: match and dump RNext_key,
447 * out: the dumped key is RNext_key
448 */
449 get_all :1, /* in: dump all keys */
450 reserved :13; /* padding, must be 0 */
451 __u8 sndid; /* in/out: dump keys with SendID */
452 __u8 rcvid; /* in/out: dump keys with RecvID */
453 __u8 prefix; /* in/out: dump keys with address/prefix */
454 __u8 maclen; /* out: key's length of authentication
455 * code (hash)
456 */
457 __u8 keyflags; /* in/out: see TCP_AO_KEYF_ */
458 __u8 keylen; /* out: length of ::key */
459 __s32 ifindex; /* in/out: L3 dev index for VRF */
460 __u64 pkt_good; /* out: verified segments */
461 __u64 pkt_bad; /* out: segments that failed verification */
462 } __attribute__((aligned(8)));
463
464 struct tcp_ao_repair { /* {s,g}etsockopt(TCP_AO_REPAIR) */
465 __be32 snt_isn;
466 __be32 rcv_isn;
467 __u32 snd_sne;
468 __u32 rcv_sne;
469 } __attribute__((aligned(8)));
470
471 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
472
473 #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
474 struct tcp_zerocopy_receive {
475 __u64 address; /* in: address of mapping */
476 __u32 length; /* in/out: number of bytes to map/mapped */
477 __u32 recv_skip_hint; /* out: amount of bytes to skip */
478 __u32 inq; /* out: amount of bytes in read queue */
479 __s32 err; /* out: socket error */
480 __u64 copybuf_address; /* in: copybuf address (small reads) */
481 __s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
482 __u32 flags; /* in: flags */
483 __u64 msg_control; /* ancillary data */
484 __u64 msg_controllen;
485 __u32 msg_flags;
486 __u32 reserved; /* set to 0 for now */
487 };
488 #endif /* _UAPI_LINUX_TCP_H */
489
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.