1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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.
7 * Definitions for the TCP protocol.
9 * Version: @(#)tcp.h 1.0.2 04/28/93
11 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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.
18 #ifndef _UAPI_LINUX_TCP_H
19 #define _UAPI_LINUX_TCP_H
21 #include <linux/types.h>
22 #include <asm/byteorder.h>
23 #include <linux/socket.h>
30 #if defined(__LITTLE_ENDIAN_BITFIELD)
41 #elif defined(__BIG_ENDIAN_BITFIELD)
53 #error "Adjust your <asm/byteorder.h> defines"
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.
70 #define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])
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)
86 * TCP general constants
88 #define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */
89 #define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */
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 */
128 #define TCP_CM_INQ TCP_INQ
130 #define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */
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 */
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 */
142 struct tcp_repair_opt {
147 struct tcp_repair_window {
163 /* why fastopen failed from client perspective */
164 enum 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 */
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 */
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.
187 * Nothing bad has been observed recently.
188 * No apparent reordering, packet loss, or ECN marks.
191 #define TCPF_CA_Open (1<<TCP_CA_Open)
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
199 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
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).
206 #define TCPF_CA_CWR (1<<TCP_CA_CWR)
208 * The sender is in fast recovery and retransmitting lost packets,
209 * typically triggered by ACK events.
212 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
214 * The sender is in loss recovery triggered by retransmission timeout.
217 #define TCPF_CA_Loss (1<<TCP_CA_Loss)
223 __u8 tcpi_retransmits;
227 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
228 __u8 tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
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;
249 __u32 tcpi_rcv_ssthresh;
252 __u32 tcpi_snd_ssthresh;
255 __u32 tcpi_reordering;
258 __u32 tcpi_rcv_space;
260 __u32 tcpi_total_retrans;
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 */
269 __u32 tcpi_notsent_bytes;
271 __u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
272 __u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */
274 __u64 tcpi_delivery_rate;
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 */
280 __u32 tcpi_delivered;
281 __u32 tcpi_delivered_ce;
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 */
288 __u32 tcpi_rcv_ooopack; /* Out-of-order packets received */
290 __u32 tcpi_snd_wnd; /* peer's advertised receive window after
293 __u32 tcpi_rcv_wnd; /* local advertised receive window after
297 __u32 tcpi_rehash; /* PLB or timeout triggered rehash attempts */
299 __u16 tcpi_total_rto; /* Total number of RTO timeouts, including
300 * SYN/SYN-ACK and recurring timeouts.
302 __u16 tcpi_total_rto_recoveries; /* Total number of RTO
303 * recoveries, including any
304 * unfinished recovery.
306 __u32 tcpi_total_rto_time; /* Total time spent in RTO recoveries
307 * in milliseconds, including any
308 * unfinished recovery.
312 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
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 */
344 /* for TCP_MD5SIG socket option */
345 #define TCP_MD5SIG_MAXKEYLEN 80
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 */
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) */
360 /* INET_DIAG_MD5SIG */
361 struct tcp_diag_md5sig {
366 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
369 #define TCP_AO_MAXKEYLEN 80
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
378 struct 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)));
395 struct 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)));
411 struct 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)));
429 struct 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
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
440 __u16 is_current :1, /* in: match and dump Current_key,
441 * out: the dumped key is Current_key
444 is_rnext :1, /* in: match and dump RNext_key,
445 * out: the dumped key is RNext_key
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
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)));
462 struct tcp_ao_repair { /* {s,g}etsockopt(TCP_AO_REPAIR) */
467 } __attribute__((aligned(8)));
469 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
471 #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
472 struct 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;
484 __u32 reserved; /* set to 0 for now */
486 #endif /* _UAPI_LINUX_TCP_H */