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
133#define TCP_REPAIR_ON 1
134#define TCP_REPAIR_OFF 0
135#define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
136
137struct tcp_repair_opt {
138 __u32 opt_code;
139 __u32 opt_val;
140};
141
142struct tcp_repair_window {
143 __u32 snd_wl1;
144 __u32 snd_wnd;
145 __u32 max_window;
146
147 __u32 rcv_wnd;
148 __u32 rcv_wup;
149};
150
151enum {
152 TCP_NO_QUEUE,
153 TCP_RECV_QUEUE,
154 TCP_SEND_QUEUE,
155 TCP_QUEUES_NR,
156};
157
158/* why fastopen failed from client perspective */
159enum tcp_fastopen_client_fail {
160 TFO_STATUS_UNSPEC, /* catch-all */
161 TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
162 TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
163 TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
164};
165
166/* for TCP_INFO socket option */
167#define TCPI_OPT_TIMESTAMPS 1
168#define TCPI_OPT_SACK 2
169#define TCPI_OPT_WSCALE 4
170#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */
171#define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */
172#define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */
173
174/*
175 * Sender's congestion state indicating normal or abnormal situations
176 * in the last round of packets sent. The state is driven by the ACK
177 * information and timer events.
178 */
179enum tcp_ca_state {
180 /*
181 * Nothing bad has been observed recently.
182 * No apparent reordering, packet loss, or ECN marks.
183 */
184 TCP_CA_Open = 0,
185#define TCPF_CA_Open (1<<TCP_CA_Open)
186 /*
187 * The sender enters disordered state when it has received DUPACKs or
188 * SACKs in the last round of packets sent. This could be due to packet
189 * loss or reordering but needs further information to confirm packets
190 * have been lost.
191 */
192 TCP_CA_Disorder = 1,
193#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
194 /*
195 * The sender enters Congestion Window Reduction (CWR) state when it
196 * has received ACKs with ECN-ECE marks, or has experienced congestion
197 * or packet discard on the sender host (e.g. qdisc).
198 */
199 TCP_CA_CWR = 2,
200#define TCPF_CA_CWR (1<<TCP_CA_CWR)
201 /*
202 * The sender is in fast recovery and retransmitting lost packets,
203 * typically triggered by ACK events.
204 */
205 TCP_CA_Recovery = 3,
206#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
207 /*
208 * The sender is in loss recovery triggered by retransmission timeout.
209 */
210 TCP_CA_Loss = 4
211#define TCPF_CA_Loss (1<<TCP_CA_Loss)
212};
213
214struct tcp_info {
215 __u8 tcpi_state;
216 __u8 tcpi_ca_state;
217 __u8 tcpi_retransmits;
218 __u8 tcpi_probes;
219 __u8 tcpi_backoff;
220 __u8 tcpi_options;
221 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
222 __u8 tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
223
224 __u32 tcpi_rto;
225 __u32 tcpi_ato;
226 __u32 tcpi_snd_mss;
227 __u32 tcpi_rcv_mss;
228
229 __u32 tcpi_unacked;
230 __u32 tcpi_sacked;
231 __u32 tcpi_lost;
232 __u32 tcpi_retrans;
233 __u32 tcpi_fackets;
234
235 /* Times. */
236 __u32 tcpi_last_data_sent;
237 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
238 __u32 tcpi_last_data_recv;
239 __u32 tcpi_last_ack_recv;
240
241 /* Metrics. */
242 __u32 tcpi_pmtu;
243 __u32 tcpi_rcv_ssthresh;
244 __u32 tcpi_rtt;
245 __u32 tcpi_rttvar;
246 __u32 tcpi_snd_ssthresh;
247 __u32 tcpi_snd_cwnd;
248 __u32 tcpi_advmss;
249 __u32 tcpi_reordering;
250
251 __u32 tcpi_rcv_rtt;
252 __u32 tcpi_rcv_space;
253
254 __u32 tcpi_total_retrans;
255
256 __u64 tcpi_pacing_rate;
257 __u64 tcpi_max_pacing_rate;
258 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
259 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
260 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
261 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */
262
263 __u32 tcpi_notsent_bytes;
264 __u32 tcpi_min_rtt;
265 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
266 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
267
268 __u64 tcpi_delivery_rate;
269
270 __u64 tcpi_busy_time; /* Time (usec) busy sending data */
271 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
272 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
273
274 __u32 tcpi_delivered;
275 __u32 tcpi_delivered_ce;
276
277 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
278 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
279 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */
280 __u32 tcpi_reord_seen; /* reordering events seen */
281
282 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */
283
284 __u32 tcpi_snd_wnd; /* peer's advertised receive window after
285 * scaling (bytes)
286 */
287};
288
289/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
290enum {
291 TCP_NLA_PAD,
292 TCP_NLA_BUSY, /* Time (usec) busy sending data */
293 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
294 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
295 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
296 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
297 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
298 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
299 TCP_NLA_SND_CWND, /* Sending congestion window */
300 TCP_NLA_REORDERING, /* Reordering metric */
301 TCP_NLA_MIN_RTT, /* minimum RTT */
302 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
303 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
304 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
305 TCP_NLA_CA_STATE, /* ca_state of socket */
306 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
307 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
308 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
309 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
310 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */
311 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */
312 TCP_NLA_REORD_SEEN, /* reordering events seen */
313 TCP_NLA_SRTT, /* smoothed RTT in usecs */
314 TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
315 TCP_NLA_BYTES_NOTSENT, /* Bytes in write queue not yet sent */
316 TCP_NLA_EDT, /* Earliest departure time (CLOCK_MONOTONIC) */
317 TCP_NLA_TTL, /* TTL or hop limit of a packet received */
318};
319
320/* for TCP_MD5SIG socket option */
321#define TCP_MD5SIG_MAXKEYLEN 80
322
323/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
324#define TCP_MD5SIG_FLAG_PREFIX 0x1 /* address prefix length */
325#define TCP_MD5SIG_FLAG_IFINDEX 0x2 /* ifindex set */
326
327struct tcp_md5sig {
328 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
329 __u8 tcpm_flags; /* extension flags */
330 __u8 tcpm_prefixlen; /* address prefix */
331 __u16 tcpm_keylen; /* key length */
332 int tcpm_ifindex; /* device index for scope */
333 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
334};
335
336/* INET_DIAG_MD5SIG */
337struct tcp_diag_md5sig {
338 __u8 tcpm_family;
339 __u8 tcpm_prefixlen;
340 __u16 tcpm_keylen;
341 __be32 tcpm_addr[4];
342 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
343};
344
345/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
346
347#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
348struct tcp_zerocopy_receive {
349 __u64 address; /* in: address of mapping */
350 __u32 length; /* in/out: number of bytes to map/mapped */
351 __u32 recv_skip_hint; /* out: amount of bytes to skip */
352 __u32 inq; /* out: amount of bytes in read queue */
353 __s32 err; /* out: socket error */
354 __u64 copybuf_address; /* in: copybuf address (small reads) */
355 __s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
356 __u32 flags; /* in: flags */
357 __u64 msg_control; /* ancillary data */
358 __u64 msg_controllen;
359 __u32 msg_flags;
360 __u32 reserved; /* set to 0 for now */
361};
362#endif /* _UAPI_LINUX_TCP_H */
363

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