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
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
137 struct tcp_repair_opt {
138 __u32 opt_code;
139 __u32 opt_val;
140 };
141
142 struct 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
151 enum {
152 TCP_NO_QUEUE,
153 TCP_RECV_QUEUE,
154 TCP_SEND_QUEUE,
155 TCP_QUEUES_NR,
156 };
157
158 /* for TCP_INFO socket option */
159 #define TCPI_OPT_TIMESTAMPS 1
160 #define TCPI_OPT_SACK 2
161 #define TCPI_OPT_WSCALE 4
162 #define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */
163 #define TCPI_OPT_ECN_SEEN 16 /* we received at least one packet with ECT */
164 #define TCPI_OPT_SYN_DATA 32 /* SYN-ACK acked data in SYN sent or rcvd */
165
166 /*
167 * Sender's congestion state indicating normal or abnormal situations
168 * in the last round of packets sent. The state is driven by the ACK
169 * information and timer events.
170 */
171 enum tcp_ca_state {
172 /*
173 * Nothing bad has been observed recently.
174 * No apparent reordering, packet loss, or ECN marks.
175 */
176 TCP_CA_Open = 0,
177 #define TCPF_CA_Open (1<<TCP_CA_Open)
178 /*
179 * The sender enters disordered state when it has received DUPACKs or
180 * SACKs in the last round of packets sent. This could be due to packet
181 * loss or reordering but needs further information to confirm packets
182 * have been lost.
183 */
184 TCP_CA_Disorder = 1,
185 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
186 /*
187 * The sender enters Congestion Window Reduction (CWR) state when it
188 * has received ACKs with ECN-ECE marks, or has experienced congestion
189 * or packet discard on the sender host (e.g. qdisc).
190 */
191 TCP_CA_CWR = 2,
192 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
193 /*
194 * The sender is in fast recovery and retransmitting lost packets,
195 * typically triggered by ACK events.
196 */
197 TCP_CA_Recovery = 3,
198 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
199 /*
200 * The sender is in loss recovery triggered by retransmission timeout.
201 */
202 TCP_CA_Loss = 4
203 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
204 };
205
206 struct tcp_info {
207 __u8 tcpi_state;
208 __u8 tcpi_ca_state;
209 __u8 tcpi_retransmits;
210 __u8 tcpi_probes;
211 __u8 tcpi_backoff;
212 __u8 tcpi_options;
213 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
214 __u8 tcpi_delivery_rate_app_limited:1;
215
216 __u32 tcpi_rto;
217 __u32 tcpi_ato;
218 __u32 tcpi_snd_mss;
219 __u32 tcpi_rcv_mss;
220
221 __u32 tcpi_unacked;
222 __u32 tcpi_sacked;
223 __u32 tcpi_lost;
224 __u32 tcpi_retrans;
225 __u32 tcpi_fackets;
226
227 /* Times. */
228 __u32 tcpi_last_data_sent;
229 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
230 __u32 tcpi_last_data_recv;
231 __u32 tcpi_last_ack_recv;
232
233 /* Metrics. */
234 __u32 tcpi_pmtu;
235 __u32 tcpi_rcv_ssthresh;
236 __u32 tcpi_rtt;
237 __u32 tcpi_rttvar;
238 __u32 tcpi_snd_ssthresh;
239 __u32 tcpi_snd_cwnd;
240 __u32 tcpi_advmss;
241 __u32 tcpi_reordering;
242
243 __u32 tcpi_rcv_rtt;
244 __u32 tcpi_rcv_space;
245
246 __u32 tcpi_total_retrans;
247
248 __u64 tcpi_pacing_rate;
249 __u64 tcpi_max_pacing_rate;
250 __u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
251 __u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
252 __u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
253 __u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */
254
255 __u32 tcpi_notsent_bytes;
256 __u32 tcpi_min_rtt;
257 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
258 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
259
260 __u64 tcpi_delivery_rate;
261
262 __u64 tcpi_busy_time; /* Time (usec) busy sending data */
263 __u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
264 __u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
265
266 __u32 tcpi_delivered;
267 __u32 tcpi_delivered_ce;
268
269 __u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
270 __u64 tcpi_bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans */
271 __u32 tcpi_dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups */
272 __u32 tcpi_reord_seen; /* reordering events seen */
273
274 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */
275
276 __u32 tcpi_snd_wnd; /* peer's advertised receive window after
277 * scaling (bytes)
278 */
279 };
280
281 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
282 enum {
283 TCP_NLA_PAD,
284 TCP_NLA_BUSY, /* Time (usec) busy sending data */
285 TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
286 TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
287 TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
288 TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
289 TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
290 TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
291 TCP_NLA_SND_CWND, /* Sending congestion window */
292 TCP_NLA_REORDERING, /* Reordering metric */
293 TCP_NLA_MIN_RTT, /* minimum RTT */
294 TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
295 TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
296 TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
297 TCP_NLA_CA_STATE, /* ca_state of socket */
298 TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
299 TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
300 TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
301 TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
302 TCP_NLA_BYTES_RETRANS, /* Data bytes retransmitted */
303 TCP_NLA_DSACK_DUPS, /* DSACK blocks received */
304 TCP_NLA_REORD_SEEN, /* reordering events seen */
305 TCP_NLA_SRTT, /* smoothed RTT in usecs */
306 };
307
308 /* for TCP_MD5SIG socket option */
309 #define TCP_MD5SIG_MAXKEYLEN 80
310
311 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
312 #define TCP_MD5SIG_FLAG_PREFIX 1 /* address prefix length */
313
314 struct tcp_md5sig {
315 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
316 __u8 tcpm_flags; /* extension flags */
317 __u8 tcpm_prefixlen; /* address prefix */
318 __u16 tcpm_keylen; /* key length */
319 __u32 __tcpm_pad; /* zero */
320 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
321 };
322
323 /* INET_DIAG_MD5SIG */
324 struct tcp_diag_md5sig {
325 __u8 tcpm_family;
326 __u8 tcpm_prefixlen;
327 __u16 tcpm_keylen;
328 __be32 tcpm_addr[4];
329 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
330 };
331
332 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
333
334 struct tcp_zerocopy_receive {
335 __u64 address; /* in: address of mapping */
336 __u32 length; /* in/out: number of bytes to map/mapped */
337 __u32 recv_skip_hint; /* out: amount of bytes to skip */
338 };
339 #endif /* _UAPI_LINUX_TCP_H */