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_REPAIR_ON 1
131#define TCP_REPAIR_OFF 0
132#define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
133
134struct tcp_repair_opt {
135 __u32 opt_code;
136 __u32 opt_val;
137};
138
139struct tcp_repair_window {
140 __u32 snd_wl1;
141 __u32 snd_wnd;
142 __u32 max_window;
143
144 __u32 rcv_wnd;
145 __u32 rcv_wup;
146};
147
148enum {
149 TCP_NO_QUEUE,
150 TCP_RECV_QUEUE,
151 TCP_SEND_QUEUE,
152 TCP_QUEUES_NR,
153};
154
155/* for TCP_INFO socket option */
156#define TCPI_OPT_TIMESTAMPS 1
157#define TCPI_OPT_SACK 2
158#define TCPI_OPT_WSCALE 4
159#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */
160#define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */
161#define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */
162
163enum tcp_ca_state {
164 TCP_CA_Open = 0,
165#define TCPF_CA_Open (1<<TCP_CA_Open)
166 TCP_CA_Disorder = 1,
167#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
168 TCP_CA_CWR = 2,
169#define TCPF_CA_CWR (1<<TCP_CA_CWR)
170 TCP_CA_Recovery = 3,
171#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
172 TCP_CA_Loss = 4
173#define TCPF_CA_Loss (1<<TCP_CA_Loss)
174};
175
176struct tcp_info {
177 __u8 tcpi_state;
178 __u8 tcpi_ca_state;
179 __u8 tcpi_retransmits;
180 __u8 tcpi_probes;
181 __u8 tcpi_backoff;
182 __u8 tcpi_options;
183 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
184 __u8 tcpi_delivery_rate_app_limited:1;
185
186 __u32 tcpi_rto;
187 __u32 tcpi_ato;
188 __u32 tcpi_snd_mss;
189 __u32 tcpi_rcv_mss;
190
191 __u32 tcpi_unacked;
192 __u32 tcpi_sacked;
193 __u32 tcpi_lost;
194 __u32 tcpi_retrans;
195 __u32 tcpi_fackets;
196
197 /* Times. */
198 __u32 tcpi_last_data_sent;
199 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
200 __u32 tcpi_last_data_recv;
201 __u32 tcpi_last_ack_recv;
202
203 /* Metrics. */
204 __u32 tcpi_pmtu;
205 __u32 tcpi_rcv_ssthresh;
206 __u32 tcpi_rtt;
207 __u32 tcpi_rttvar;
208 __u32 tcpi_snd_ssthresh;
209 __u32 tcpi_snd_cwnd;
210 __u32 tcpi_advmss;
211 __u32 tcpi_reordering;
212
213 __u32 tcpi_rcv_rtt;
214 __u32 tcpi_rcv_space;
215
216 __u32 tcpi_total_retrans;
217
218 __u64 tcpi_pacing_rate;
219 __u64 tcpi_max_pacing_rate;
220 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
221 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
222 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
223 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */
224
225 __u32 tcpi_notsent_bytes;
226 __u32 tcpi_min_rtt;
227 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
228 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
229
230 __u64 tcpi_delivery_rate;
231
232 __u64 tcpi_busy_time; /* Time (usec) busy sending data */
233 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
234 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
235
236 __u32 tcpi_delivered;
237 __u32 tcpi_delivered_ce;
238
239 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
240 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
241 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */
242 __u32 tcpi_reord_seen; /* reordering events seen */
243};
244
245/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
246enum {
247 TCP_NLA_PAD,
248 TCP_NLA_BUSY, /* Time (usec) busy sending data */
249 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
250 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
251 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
252 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
253 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
254 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
255 TCP_NLA_SND_CWND, /* Sending congestion window */
256 TCP_NLA_REORDERING, /* Reordering metric */
257 TCP_NLA_MIN_RTT, /* minimum RTT */
258 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
259 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
260 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
261 TCP_NLA_CA_STATE, /* ca_state of socket */
262 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
263 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
264 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
265 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
266 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */
267 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */
268 TCP_NLA_REORD_SEEN, /* reordering events seen */
269 TCP_NLA_SRTT, /* smoothed RTT in usecs */
270};
271
272/* for TCP_MD5SIG socket option */
273#define TCP_MD5SIG_MAXKEYLEN 80
274
275/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
276#define TCP_MD5SIG_FLAG_PREFIX 1 /* address prefix length */
277
278struct tcp_md5sig {
279 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
280 __u8 tcpm_flags; /* extension flags */
281 __u8 tcpm_prefixlen; /* address prefix */
282 __u16 tcpm_keylen; /* key length */
283 __u32 __tcpm_pad; /* zero */
284 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
285};
286
287/* INET_DIAG_MD5SIG */
288struct tcp_diag_md5sig {
289 __u8 tcpm_family;
290 __u8 tcpm_prefixlen;
291 __u16 tcpm_keylen;
292 __be32 tcpm_addr[4];
293 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
294};
295
296/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
297
298struct tcp_zerocopy_receive {
299 __u64 address; /* in: address of mapping */
300 __u32 length; /* in/out: number of bytes to map/mapped */
301 __u32 recv_skip_hint; /* out: amount of bytes to skip */
302};
303#endif /* _UAPI_LINUX_TCP_H */
304