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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Definitions for the TCP module.
7 *
8 * Version: @(#)tcp.h 1.0.5 05/23/93
9 *
Jesper Juhl02c30a82005-05-05 16:16:16 -070010 * Authors: Ross Biro
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * 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 _TCP_H
19#define _TCP_H
20
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#define FASTRETRANS_DEBUG 1
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/list.h>
24#include <linux/tcp.h>
Paul Gortmaker187f1882011-11-23 20:12:59 -050025#include <linux/bug.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/slab.h>
27#include <linux/cache.h>
28#include <linux/percpu.h>
Herbert Xufb286bb2005-11-10 13:01:24 -080029#include <linux/skbuff.h>
Glenn Griffinc6aefaf2008-02-07 21:49:26 -080030#include <linux/cryptohash.h>
William Allen Simpson435cf552009-12-02 18:17:05 +000031#include <linux/kref.h>
Eric Dumazet740b0f12014-02-26 14:02:48 -080032#include <linux/ktime.h>
Arnaldo Carvalho de Melo3f421ba2005-08-09 20:11:08 -070033
34#include <net/inet_connection_sock.h>
Arnaldo Carvalho de Melo295ff7e2005-08-09 20:44:40 -070035#include <net/inet_timewait_sock.h>
Arnaldo Carvalho de Melo77d8bf92005-08-09 20:00:51 -070036#include <net/inet_hashtables.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#include <net/checksum.h>
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070038#include <net/request_sock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include <net/sock.h>
40#include <net/snmp.h>
41#include <net/ip.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070042#include <net/tcp_states.h>
Ilpo Järvinenbdf1ee52007-05-27 02:04:16 -070043#include <net/inet_ecn.h>
Satoru SATOH0c266892009-05-04 11:11:01 -070044#include <net/dst.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070045
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/seq_file.h>
Glauber Costa180d8cd2011-12-11 21:47:02 +000047#include <linux/memcontrol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Arnaldo Carvalho de Melo6e04e022005-08-09 20:07:35 -070049extern struct inet_hashinfo tcp_hashinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Eric Dumazetdd24c002008-11-25 21:17:14 -080051extern struct percpu_counter tcp_orphan_count;
Joe Perches5c9f3022013-09-23 11:33:32 -070052void tcp_time_wait(struct sock *sk, int state, int timeo);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Linus Torvalds1da177e2005-04-16 15:20:36 -070054#define MAX_TCP_HEADER (128 + MAX_HEADER)
Adam Langley33ad7982008-07-19 00:04:31 -070055#define MAX_TCP_OPTION_SPACE 40
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Kenjiro Nakayama105970f2014-10-20 18:15:50 +090057/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 * Never offer a window over 32767 without using window scaling. Some
Kenjiro Nakayama105970f2014-10-20 18:15:50 +090059 * poor stacks do signed 16bit maths!
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 */
61#define MAX_TCP_WINDOW 32767U
62
63/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
64#define TCP_MIN_MSS 88U
65
John Heffner5d424d52006-03-20 17:53:41 -080066/* The least MTU to use for probing */
Fan Dudcd8fb82015-03-06 11:18:22 +080067#define TCP_BASE_MSS 1024
John Heffner5d424d52006-03-20 17:53:41 -080068
Fan Du05cbc0d2015-03-06 11:18:24 +080069/* probing interval, default to 10 minutes as per RFC4821 */
70#define TCP_PROBE_INTERVAL 600
71
Fan Du6b58e0a2015-03-06 11:18:23 +080072/* Specify interval when tcp mtu probing will stop */
73#define TCP_PROBE_THRESHOLD 8
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075/* After receiving this amount of duplicate ACKs fast retransmit starts. */
76#define TCP_FASTRETRANS_THRESH 3
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078/* Maximal number of ACKs sent quickly to accelerate slow-start. */
79#define TCP_MAX_QUICKACKS 16U
80
Gao Feng589c49c2017-04-04 21:09:48 +080081/* Maximal number of window scale according to RFC1323 */
82#define TCP_MAX_WSCALE 14U
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084/* urg_data states */
85#define TCP_URG_VALID 0x0100
86#define TCP_URG_NOTYET 0x0200
87#define TCP_URG_READ 0x0400
88
89#define TCP_RETR1 3 /*
90 * This is how many retries it does before it
91 * tries to figure out if the gateway is
92 * down. Minimal RFC value is 3; it corresponds
93 * to ~3sec-8min depending on RTO.
94 */
95
96#define TCP_RETR2 15 /*
97 * This should take at least
98 * 90 minutes to time out.
99 * RFC1122 says that the limit is 100 sec.
100 * 15 is ~13-30min depending on RTO.
101 */
102
Alex Bergmann6c9ff972012-08-31 02:48:31 +0000103#define TCP_SYN_RETRIES 6 /* This is how many retries are done
104 * when active opening a connection.
105 * RFC1122 says the minimum retry MUST
106 * be at least 180secs. Nevertheless
107 * this value is corresponding to
108 * 63secs of retransmission with the
109 * current initial RTO.
110 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
Alex Bergmann6c9ff972012-08-31 02:48:31 +0000112#define TCP_SYNACK_RETRIES 5 /* This is how may retries are done
113 * when passive opening a connection.
114 * This is corresponding to 31secs of
115 * retransmission with the current
116 * initial RTO.
117 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
120 * state, about 60 seconds */
121#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
122 /* BSD style FIN_WAIT2 deadlock breaker.
123 * It used to be 3min, new value is 60sec,
124 * to combine FIN-WAIT-2 timeout with
125 * TIME-WAIT timer.
126 */
127
128#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
129#if HZ >= 100
130#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
131#define TCP_ATO_MIN ((unsigned)(HZ/25))
132#else
133#define TCP_DELACK_MIN 4U
134#define TCP_ATO_MIN 4U
135#endif
136#define TCP_RTO_MAX ((unsigned)(120*HZ))
137#define TCP_RTO_MIN ((unsigned)(HZ/5))
Eric Dumazetfd4f2ce2012-04-12 19:48:40 +0000138#define TCP_TIMEOUT_INIT ((unsigned)(1*HZ)) /* RFC6298 2.1 initial RTO value */
Jerry Chu9ad7c042011-06-08 11:08:38 +0000139#define TCP_TIMEOUT_FALLBACK ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value, now
140 * used as a fallback RTO for the
141 * initial data transmission if no
142 * valid RTT sample has been acquired,
143 * most likely due to retrans in 3WHS.
144 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
147 * for local resources.
148 */
Yuchung Cheng57dde7f2017-01-12 22:11:33 -0800149#define TCP_REO_TIMEOUT_MIN (2000) /* Min RACK reordering timeout in usec */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
152#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
153#define TCP_KEEPALIVE_INTVL (75*HZ)
154
155#define MAX_TCP_KEEPIDLE 32767
156#define MAX_TCP_KEEPINTVL 32767
157#define MAX_TCP_KEEPCNT 127
158#define MAX_TCP_SYNCNT 127
159
160#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
162#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
163#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
164 * after this time. It should be equal
165 * (or greater than) TCP_TIMEWAIT_LEN
166 * to provide reliability equal to one
167 * provided by timewait state.
168 */
169#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
170 * timestamps. It must be less than
171 * minimal timewait lifetime.
172 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173/*
174 * TCP option
175 */
Kenjiro Nakayama105970f2014-10-20 18:15:50 +0900176
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177#define TCPOPT_NOP 1 /* Padding */
178#define TCPOPT_EOL 0 /* End of options */
179#define TCPOPT_MSS 2 /* Segment size negotiating */
180#define TCPOPT_WINDOW 3 /* Window scaling */
181#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
182#define TCPOPT_SACK 5 /* SACK Block */
183#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800184#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
Daniel Lee7f9b8382015-04-06 14:37:26 -0700185#define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
Yuchung Cheng2100c8d2012-07-19 06:43:05 +0000186#define TCPOPT_EXP 254 /* Experimental */
187/* Magic number to be after the option value for sharing TCP
188 * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
189 */
190#define TCPOPT_FASTOPEN_MAGIC 0xF989
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
192/*
193 * TCP option lengths
194 */
195
196#define TCPOLEN_MSS 4
197#define TCPOLEN_WINDOW 3
198#define TCPOLEN_SACK_PERM 2
199#define TCPOLEN_TIMESTAMP 10
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800200#define TCPOLEN_MD5SIG 18
Daniel Lee7f9b8382015-04-06 14:37:26 -0700201#define TCPOLEN_FASTOPEN_BASE 2
Yuchung Cheng2100c8d2012-07-19 06:43:05 +0000202#define TCPOLEN_EXP_FASTOPEN_BASE 4
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204/* But this is what stacks really send out. */
205#define TCPOLEN_TSTAMP_ALIGNED 12
206#define TCPOLEN_WSCALE_ALIGNED 4
207#define TCPOLEN_SACKPERM_ALIGNED 4
208#define TCPOLEN_SACK_BASE 2
209#define TCPOLEN_SACK_BASE_ALIGNED 4
210#define TCPOLEN_SACK_PERBLOCK 8
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800211#define TCPOLEN_MD5SIG_ALIGNED 20
Adam Langley33ad7982008-07-19 00:04:31 -0700212#define TCPOLEN_MSS_ALIGNED 4
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214/* Flags in tp->nonagle */
215#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
216#define TCP_NAGLE_CORK 2 /* Socket is corked */
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -0800217#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Andreas Petlund36e31b0a2010-02-18 02:47:01 +0000219/* TCP thin-stream limits */
220#define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
221
Jörg Thalheim21603fc2016-01-27 22:54:06 +0100222/* TCP initial congestion window as per rfc6928 */
David S. Miller442b9632011-02-02 17:05:11 -0800223#define TCP_INIT_CWND 10
224
Yuchung Chengcf60af02012-07-19 06:43:09 +0000225/* Bit Flags for sysctl_tcp_fastopen */
226#define TFO_CLIENT_ENABLE 1
Jerry Chu10467162012-08-31 12:29:11 +0000227#define TFO_SERVER_ENABLE 2
Yuchung Cheng67da22d2012-07-19 06:43:11 +0000228#define TFO_CLIENT_NO_COOKIE 4 /* Data in SYN w/o cookie option */
Yuchung Chengcf60af02012-07-19 06:43:09 +0000229
Jerry Chu10467162012-08-31 12:29:11 +0000230/* Accept SYN data w/o any cookie option */
231#define TFO_SERVER_COOKIE_NOT_REQD 0x200
232
233/* Force enable TFO on all listeners, i.e., not requiring the
Yuchung Chengcebc5cb2016-08-22 17:17:54 -0700234 * TCP_FASTOPEN socket option.
Jerry Chu10467162012-08-31 12:29:11 +0000235 */
236#define TFO_SERVER_WO_SOCKOPT1 0x400
Jerry Chu10467162012-08-31 12:29:11 +0000237
Arnaldo Carvalho de Melo295ff7e2005-08-09 20:44:40 -0700238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239/* sysctl variables for tcp */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240extern int sysctl_tcp_timestamps;
241extern int sysctl_tcp_window_scaling;
242extern int sysctl_tcp_sack;
Yuchung Cheng2100c8d2012-07-19 06:43:05 +0000243extern int sysctl_tcp_fastopen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244extern int sysctl_tcp_retrans_collapse;
245extern int sysctl_tcp_stdurg;
246extern int sysctl_tcp_rfc1337;
247extern int sysctl_tcp_abort_on_overflow;
248extern int sysctl_tcp_max_orphans;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249extern int sysctl_tcp_fack;
250extern int sysctl_tcp_reordering;
Eric Dumazetdca145f2014-10-27 21:45:24 -0700251extern int sysctl_tcp_max_reordering;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252extern int sysctl_tcp_dsack;
Eric W. Biedermana4fe34b2013-10-19 16:25:36 -0700253extern long sysctl_tcp_mem[3];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254extern int sysctl_tcp_wmem[3];
255extern int sysctl_tcp_rmem[3];
256extern int sysctl_tcp_app_win;
257extern int sysctl_tcp_adv_win_scale;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258extern int sysctl_tcp_frto;
259extern int sysctl_tcp_low_latency;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260extern int sysctl_tcp_nometrics_save;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261extern int sysctl_tcp_moderate_rcvbuf;
262extern int sysctl_tcp_tso_win_divisor;
Rick Jones15d99e02006-03-20 22:40:29 -0800263extern int sysctl_tcp_workaround_signed_windows;
David S. Miller35089bb2006-06-13 22:33:04 -0700264extern int sysctl_tcp_slow_start_after_idle;
Andreas Petlund36e31b0a2010-02-18 02:47:01 +0000265extern int sysctl_tcp_thin_linear_timeouts;
Andreas Petlund7e380172010-02-18 04:48:19 +0000266extern int sysctl_tcp_thin_dupack;
Yuchung Chengeed530b2012-05-02 13:30:03 +0000267extern int sysctl_tcp_early_retrans;
Yuchung Chenga0370b32017-01-12 22:11:36 -0800268extern int sysctl_tcp_recovery;
269#define TCP_RACK_LOSS_DETECTION 0x1 /* Use RACK to detect losses */
270
Eric Dumazet46d3cea2012-07-11 05:50:31 +0000271extern int sysctl_tcp_limit_output_bytes;
Eric Dumazet282f23c2012-07-17 10:13:05 +0200272extern int sysctl_tcp_challenge_ack_limit;
Eric Dumazet95bd09e2013-08-27 05:46:32 -0700273extern int sysctl_tcp_min_tso_segs;
Yuchung Chengf6722582015-10-16 21:57:42 -0700274extern int sysctl_tcp_min_rtt_wlen;
Eric Dumazetf54b3112013-12-05 22:36:05 -0800275extern int sysctl_tcp_autocorking;
Neal Cardwell032ee422015-02-06 16:04:38 -0500276extern int sysctl_tcp_invalid_ratelimit;
Eric Dumazet43e122b2015-08-21 17:38:02 -0700277extern int sysctl_tcp_pacing_ss_ratio;
278extern int sysctl_tcp_pacing_ca_ratio;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
Eric Dumazet8d987e52010-11-09 23:24:26 +0000280extern atomic_long_t tcp_memory_allocated;
Eric Dumazet17483762008-11-25 21:16:35 -0800281extern struct percpu_counter tcp_sockets_allocated;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282extern int tcp_memory_pressure;
283
Eric Dumazetb8da51e2015-05-15 12:39:27 -0700284/* optimized version of sk_under_memory_pressure() for TCP sockets */
285static inline bool tcp_under_memory_pressure(const struct sock *sk)
286{
Johannes Weinerbaac50b2016-01-14 15:21:17 -0800287 if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
288 mem_cgroup_under_socket_pressure(sk->sk_memcg))
Johannes Weinere8056052016-01-14 15:21:14 -0800289 return true;
Eric Dumazetb8da51e2015-05-15 12:39:27 -0700290
291 return tcp_memory_pressure;
292}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 * The next routines deal with comparing 32 bit unsigned ints
295 * and worry about wraparound (automatic with unsigned arithmetic).
296 */
297
Eric Dumazeta2a385d2012-05-16 23:15:34 +0000298static inline bool before(__u32 seq1, __u32 seq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299{
Gerrit Renker0d630cc2007-01-04 12:25:16 -0800300 return (__s32)(seq1-seq2) < 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301}
Gerrit Renker9a036b9c2006-12-20 10:25:55 -0800302#define after(seq2, seq1) before(seq1, seq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304/* is s2<=s1<=s3 ? */
Eric Dumazeta2a385d2012-05-16 23:15:34 +0000305static inline bool between(__u32 seq1, __u32 seq2, __u32 seq3)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306{
307 return seq3 - seq2 >= seq1 - seq2;
308}
309
Arun Sharmaefcdbf22012-01-30 14:16:06 -0800310static inline bool tcp_out_of_memory(struct sock *sk)
311{
312 if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
313 sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
314 return true;
315 return false;
316}
317
Eric Dumazeta6c5ea42015-05-15 12:39:26 -0700318void sk_forced_mem_schedule(struct sock *sk, int size);
319
David S. Millerad1af0f2010-08-25 02:27:49 -0700320static inline bool tcp_too_many_orphans(struct sock *sk, int shift)
Pavel Emelianove4fd5da2007-05-29 13:19:18 -0700321{
David S. Millerad1af0f2010-08-25 02:27:49 -0700322 struct percpu_counter *ocp = sk->sk_prot->orphan_count;
323 int orphans = percpu_counter_read_positive(ocp);
324
325 if (orphans << shift > sysctl_tcp_max_orphans) {
326 orphans = percpu_counter_sum_positive(ocp);
327 if (orphans << shift > sysctl_tcp_max_orphans)
328 return true;
329 }
David S. Millerad1af0f2010-08-25 02:27:49 -0700330 return false;
Pavel Emelianove4fd5da2007-05-29 13:19:18 -0700331}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332
Joe Perches5c9f3022013-09-23 11:33:32 -0700333bool tcp_check_oom(struct sock *sk, int shift);
Arun Sharmaefcdbf22012-01-30 14:16:06 -0800334
Florian Westphala0f82f62009-04-19 09:43:48 +0000335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336extern struct proto tcp_prot;
337
Pavel Emelyanov57ef42d2008-07-18 04:02:08 -0700338#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
Eric Dumazet13415e42016-04-27 16:44:43 -0700339#define __TCP_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.tcp_statistics, field)
Pavel Emelyanov57ef42d2008-07-18 04:02:08 -0700340#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
Tom Herbertaa2ea052010-04-22 07:00:24 +0000341#define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
Joe Perches5c9f3022013-09-23 11:33:32 -0700343void tcp_tasklet_init(void);
Eric Dumazet46d3cea2012-07-11 05:50:31 +0000344
Joe Perches5c9f3022013-09-23 11:33:32 -0700345void tcp_v4_err(struct sk_buff *skb, u32);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Joe Perches5c9f3022013-09-23 11:33:32 -0700347void tcp_shutdown(struct sock *sk, int how);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
Joe Perches5c9f3022013-09-23 11:33:32 -0700349void tcp_v4_early_demux(struct sk_buff *skb);
350int tcp_v4_rcv(struct sk_buff *skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
Joe Perches5c9f3022013-09-23 11:33:32 -0700352int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
Ying Xue1b784142015-03-02 15:37:48 +0800353int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
Joe Perches5c9f3022013-09-23 11:33:32 -0700354int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size,
355 int flags);
356void tcp_release_cb(struct sock *sk);
357void tcp_wfree(struct sk_buff *skb);
358void tcp_write_timer_handler(struct sock *sk);
359void tcp_delack_timer_handler(struct sock *sk);
360int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
Eric Dumazet72ab4a82015-09-29 07:42:41 -0700361int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
Joe Perches5c9f3022013-09-23 11:33:32 -0700362void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
363 const struct tcphdr *th, unsigned int len);
364void tcp_rcv_space_adjust(struct sock *sk);
Joe Perches5c9f3022013-09-23 11:33:32 -0700365int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
366void tcp_twsk_destructor(struct sock *sk);
367ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
368 struct pipe_inode_info *pipe, size_t len,
369 unsigned int flags);
Jens Axboe9c55e012007-11-06 23:30:13 -0800370
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700371static inline void tcp_dec_quickack_mode(struct sock *sk,
372 const unsigned int pkts)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373{
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700374 struct inet_connection_sock *icsk = inet_csk(sk);
David S. Millerfc6415bc2005-07-05 15:17:45 -0700375
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700376 if (icsk->icsk_ack.quick) {
377 if (pkts >= icsk->icsk_ack.quick) {
378 icsk->icsk_ack.quick = 0;
David S. Millerfc6415bc2005-07-05 15:17:45 -0700379 /* Leaving quickack mode we deflate ATO. */
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700380 icsk->icsk_ack.ato = TCP_ATO_MIN;
David S. Millerfc6415bc2005-07-05 15:17:45 -0700381 } else
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700382 icsk->icsk_ack.quick -= pkts;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 }
384}
385
Ilpo Järvinenbdf1ee52007-05-27 02:04:16 -0700386#define TCP_ECN_OK 1
387#define TCP_ECN_QUEUE_CWR 2
388#define TCP_ECN_DEMAND_CWR 4
Eric Dumazet7a269ff2011-09-22 20:02:19 +0000389#define TCP_ECN_SEEN 8
Ilpo Järvinenbdf1ee52007-05-27 02:04:16 -0700390
Eric Dumazetfd2c3ef2009-11-03 03:26:03 +0000391enum tcp_tw_status {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 TCP_TW_SUCCESS = 0,
393 TCP_TW_RST = 1,
394 TCP_TW_ACK = 2,
395 TCP_TW_SYN = 3
396};
397
398
Joe Perches5c9f3022013-09-23 11:33:32 -0700399enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
400 struct sk_buff *skb,
401 const struct tcphdr *th);
402struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
Eric Dumazet52452c52015-03-19 19:04:19 -0700403 struct request_sock *req, bool fastopen);
Joe Perches5c9f3022013-09-23 11:33:32 -0700404int tcp_child_process(struct sock *parent, struct sock *child,
405 struct sk_buff *skb);
Neal Cardwell5ae344c2014-08-04 19:12:29 -0400406void tcp_enter_loss(struct sock *sk);
Yuchung Cheng57dde7f2017-01-12 22:11:33 -0800407void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int flag);
Joe Perches5c9f3022013-09-23 11:33:32 -0700408void tcp_clear_retrans(struct tcp_sock *tp);
409void tcp_update_metrics(struct sock *sk);
410void tcp_init_metrics(struct sock *sk);
411void tcp_metrics_init(void);
Soheil Hassas Yeganehd82bae12017-03-15 16:30:45 -0400412bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst);
Joe Perches5c9f3022013-09-23 11:33:32 -0700413void tcp_disable_fack(struct tcp_sock *tp);
414void tcp_close(struct sock *sk, long timeout);
415void tcp_init_sock(struct sock *sk);
416unsigned int tcp_poll(struct file *file, struct socket *sock,
417 struct poll_table_struct *wait);
418int tcp_getsockopt(struct sock *sk, int level, int optname,
419 char __user *optval, int __user *optlen);
420int tcp_setsockopt(struct sock *sk, int level, int optname,
421 char __user *optval, unsigned int optlen);
422int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
Changli Gao53d31762010-07-10 20:41:06 +0000423 char __user *optval, int __user *optlen);
Joe Perches5c9f3022013-09-23 11:33:32 -0700424int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
Changli Gao53d31762010-07-10 20:41:06 +0000425 char __user *optval, unsigned int optlen);
Joe Perches5c9f3022013-09-23 11:33:32 -0700426void tcp_set_keepalive(struct sock *sk, int val);
Eric Dumazet42cb80a2015-03-22 10:22:19 -0700427void tcp_syn_ack_timeout(const struct request_sock *req);
Ying Xue1b784142015-03-02 15:37:48 +0800428int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
429 int flags, int *addr_len);
Joe Perches5c9f3022013-09-23 11:33:32 -0700430void tcp_parse_options(const struct sk_buff *skb,
431 struct tcp_options_received *opt_rx,
432 int estab, struct tcp_fastopen_cookie *foc);
433const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
YOSHIFUJI Hideaki7d5d5522008-04-17 12:29:53 +0900434
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435/*
436 * TCP v4 functions exported for the inet6 API
437 */
438
Joe Perches5c9f3022013-09-23 11:33:32 -0700439void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
Neal Cardwell4fab9072014-08-14 12:40:05 -0400440void tcp_v4_mtu_reduced(struct sock *sk);
Eric Dumazet9cf74902016-02-02 19:31:12 -0800441void tcp_req_err(struct sock *sk, u32 seq, bool abort);
Joe Perches5c9f3022013-09-23 11:33:32 -0700442int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
Eric Dumazetc28c6f02015-09-29 07:42:47 -0700443struct sock *tcp_create_openreq_child(const struct sock *sk,
Joe Perches5c9f3022013-09-23 11:33:32 -0700444 struct request_sock *req,
445 struct sk_buff *skb);
Daniel Borkmann81164412015-01-05 23:57:48 +0100446void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst);
Eric Dumazet0c271712015-09-29 07:42:48 -0700447struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
Joe Perches5c9f3022013-09-23 11:33:32 -0700448 struct request_sock *req,
Eric Dumazet5e0724d2015-10-22 08:20:46 -0700449 struct dst_entry *dst,
450 struct request_sock *req_unhash,
451 bool *own_req);
Joe Perches5c9f3022013-09-23 11:33:32 -0700452int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
453int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
454int tcp_connect(struct sock *sk);
Eric Dumazetb3d05142016-04-13 22:05:39 -0700455enum tcp_synack_type {
456 TCP_SYNACK_NORMAL,
457 TCP_SYNACK_FASTOPEN,
458 TCP_SYNACK_COOKIE,
459};
Eric Dumazet5d062de2015-09-25 07:39:19 -0700460struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
Joe Perches5c9f3022013-09-23 11:33:32 -0700461 struct request_sock *req,
Eric Dumazetca6fb062015-10-02 11:43:35 -0700462 struct tcp_fastopen_cookie *foc,
Eric Dumazetb3d05142016-04-13 22:05:39 -0700463 enum tcp_synack_type synack_type);
Joe Perches5c9f3022013-09-23 11:33:32 -0700464int tcp_disconnect(struct sock *sk, int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
Pavel Emelyanov370816a2012-04-19 03:40:01 +0000466void tcp_finish_connect(struct sock *sk, struct sk_buff *skb);
Pavel Emelyanov292e8d82012-05-10 01:49:41 +0000467int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size);
Eric Dumazet63d02d12012-08-09 14:11:00 +0000468void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470/* From syncookies.c */
Eric Dumazetb80c0e72015-06-04 18:30:43 -0700471struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
472 struct request_sock *req,
Eric Dumazet84b114b2017-05-05 06:56:54 -0700473 struct dst_entry *dst, u32 tsoff);
Joe Perches5c9f3022013-09-23 11:33:32 -0700474int __cookie_v4_check(const struct iphdr *iph, const struct tcphdr *th,
475 u32 cookie);
Cong Wang461b74c2014-10-15 14:33:22 -0700476struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb);
Eric Dumazete05c82d2011-09-18 21:02:55 -0400477#ifdef CONFIG_SYN_COOKIES
Florian Westphal8c27bd72013-09-20 22:32:55 +0200478
Eric Dumazet63262312014-03-19 21:02:21 -0700479/* Syncookies use a monotonic timer which increments every 60 seconds.
Florian Westphal8c27bd72013-09-20 22:32:55 +0200480 * This counter is used both as a hash input and partially encoded into
481 * the cookie value. A cookie is only validated further if the delta
482 * between the current counter value and the encoded one is less than this,
Eric Dumazet63262312014-03-19 21:02:21 -0700483 * i.e. a sent cookie is valid only at most for 2*60 seconds (or less if
Florian Westphal8c27bd72013-09-20 22:32:55 +0200484 * the counter advances immediately after a cookie is generated).
485 */
Eric Dumazet264ea102015-05-14 14:26:56 -0700486#define MAX_SYNCOOKIE_AGE 2
487#define TCP_SYNCOOKIE_PERIOD (60 * HZ)
488#define TCP_SYNCOOKIE_VALID (MAX_SYNCOOKIE_AGE * TCP_SYNCOOKIE_PERIOD)
489
490/* syncookies: remember time of last synqueue overflow
491 * But do not dirty this field too often (once per second is enough)
Eric Dumazet3f684b42015-09-29 07:42:49 -0700492 * It is racy as we do not hold a lock, but race is very minor.
Eric Dumazet264ea102015-05-14 14:26:56 -0700493 */
Eric Dumazet3f684b42015-09-29 07:42:49 -0700494static inline void tcp_synq_overflow(const struct sock *sk)
Eric Dumazet264ea102015-05-14 14:26:56 -0700495{
496 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
497 unsigned long now = jiffies;
498
499 if (time_after(now, last_overflow + HZ))
500 tcp_sk(sk)->rx_opt.ts_recent_stamp = now;
501}
502
503/* syncookies: no recent synqueue overflow on this listening socket? */
504static inline bool tcp_synq_no_recent_overflow(const struct sock *sk)
505{
506 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
507
508 return time_after(jiffies, last_overflow + TCP_SYNCOOKIE_VALID);
509}
Florian Westphal8c27bd72013-09-20 22:32:55 +0200510
511static inline u32 tcp_cookie_time(void)
512{
Eric Dumazet63262312014-03-19 21:02:21 -0700513 u64 val = get_jiffies_64();
514
Eric Dumazet264ea102015-05-14 14:26:56 -0700515 do_div(val, TCP_SYNCOOKIE_PERIOD);
Eric Dumazet63262312014-03-19 21:02:21 -0700516 return val;
Florian Westphal8c27bd72013-09-20 22:32:55 +0200517}
518
Joe Perches5c9f3022013-09-23 11:33:32 -0700519u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
520 u16 *mssp);
Eric Dumazet3f684b42015-09-29 07:42:49 -0700521__u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
Joe Perches5c9f3022013-09-23 11:33:32 -0700522__u32 cookie_init_timestamp(struct request_sock *req);
Florian Westphalf1673382014-11-03 17:35:02 +0100523bool cookie_timestamp_decode(struct tcp_options_received *opt);
524bool cookie_ecn_ok(const struct tcp_options_received *opt,
Florian Westphalf7b3bec2014-11-03 17:35:03 +0100525 const struct net *net, const struct dst_entry *dst);
Florian Westphal4dfc2812008-04-10 03:12:40 -0700526
Glenn Griffinc6aefaf2008-02-07 21:49:26 -0800527/* From net/ipv6/syncookies.c */
Joe Perches5c9f3022013-09-23 11:33:32 -0700528int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
529 u32 cookie);
530struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
Florian Westphalf1673382014-11-03 17:35:02 +0100531
Joe Perches5c9f3022013-09-23 11:33:32 -0700532u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
533 const struct tcphdr *th, u16 *mssp);
Eric Dumazet3f684b42015-09-29 07:42:49 -0700534__u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss);
Eric Dumazete05c82d2011-09-18 21:02:55 -0400535#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536/* tcp_output.c */
537
Neal Cardwell1b3878c2016-09-19 23:39:18 -0400538u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now,
539 int min_tso_segs);
Joe Perches5c9f3022013-09-23 11:33:32 -0700540void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
541 int nonagle);
542bool tcp_may_send_now(struct sock *sk);
Eric Dumazet10d3be52016-04-21 10:55:23 -0700543int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
544int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
Joe Perches5c9f3022013-09-23 11:33:32 -0700545void tcp_retransmit_timer(struct sock *sk);
546void tcp_xmit_retransmit_queue(struct sock *);
547void tcp_simple_retransmit(struct sock *);
Yuchung Cheng57dde7f2017-01-12 22:11:33 -0800548void tcp_enter_recovery(struct sock *sk, bool ece_ack);
Joe Perches5c9f3022013-09-23 11:33:32 -0700549int tcp_trim_head(struct sock *, struct sk_buff *, u32);
Octavian Purdila6cc55e02014-06-06 17:32:37 +0300550int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int, gfp_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551
Joe Perches5c9f3022013-09-23 11:33:32 -0700552void tcp_send_probe0(struct sock *);
553void tcp_send_partial(struct sock *);
Eric Dumazete520af42015-05-06 14:26:25 -0700554int tcp_write_wakeup(struct sock *, int mib);
Joe Perches5c9f3022013-09-23 11:33:32 -0700555void tcp_send_fin(struct sock *sk);
556void tcp_send_active_reset(struct sock *sk, gfp_t priority);
557int tcp_send_synack(struct sock *);
Joe Perches5c9f3022013-09-23 11:33:32 -0700558void tcp_push_one(struct sock *, unsigned int mss_now);
559void tcp_send_ack(struct sock *sk);
560void tcp_send_delayed_ack(struct sock *sk);
561void tcp_send_loss_probe(struct sock *sk);
562bool tcp_schedule_loss_probe(struct sock *sk);
Martin KaFai Laucfea5a62016-04-19 22:39:29 -0700563void tcp_skb_collapse_tstamp(struct sk_buff *skb,
564 const struct sk_buff *next_skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
David S. Millera762a982005-07-05 15:18:51 -0700566/* tcp_input.c */
Joe Perches5c9f3022013-09-23 11:33:32 -0700567void tcp_rearm_rto(struct sock *sk);
Yuchung Cheng0f1c28a2015-09-18 11:36:14 -0700568void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req);
Joe Perches5c9f3022013-09-23 11:33:32 -0700569void tcp_reset(struct sock *sk);
Yuchung Cheng4f41b1c2015-10-16 21:57:47 -0700570void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb);
Eric Dumazete3e17b72016-02-06 11:16:28 -0800571void tcp_fin(struct sock *sk);
David S. Millera762a982005-07-05 15:18:51 -0700572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573/* tcp_timer.c */
Joe Perches5c9f3022013-09-23 11:33:32 -0700574void tcp_init_xmit_timers(struct sock *);
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700575static inline void tcp_clear_xmit_timers(struct sock *sk)
576{
Eric Dumazet218af592017-05-16 04:24:36 -0700577 hrtimer_cancel(&tcp_sk(sk)->pacing_timer);
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700578 inet_csk_clear_xmit_timers(sk);
579}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580
Joe Perches5c9f3022013-09-23 11:33:32 -0700581unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
582unsigned int tcp_current_mss(struct sock *sk);
Ilpo Järvinen0c54b852009-03-14 14:23:05 +0000583
584/* Bound MSS / TSO packet size with the half of the window */
585static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
586{
Alexey Kuznetsov01f83d62010-09-15 10:27:52 -0700587 int cutoff;
588
589 /* When peer uses tiny windows, there is no use in packetizing
590 * to sub-MSS pieces for the sake of SWS or making sure there
591 * are enough packets in the pipe for fast recovery.
592 *
593 * On the other hand, for extremely large MSS devices, handling
594 * smaller than MSS windows in this way does make sense.
595 */
Seymour, Shane M2631b792016-06-28 23:06:48 +0000596 if (tp->max_window > TCP_MSS_DEFAULT)
Alexey Kuznetsov01f83d62010-09-15 10:27:52 -0700597 cutoff = (tp->max_window >> 1);
598 else
599 cutoff = tp->max_window;
600
601 if (cutoff && pktsize > cutoff)
602 return max_t(int, cutoff, 68U - tp->tcp_header_len);
Ilpo Järvinen0c54b852009-03-14 14:23:05 +0000603 else
604 return pktsize;
605}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606
Arnaldo Carvalho de Melo17b085e2005-08-12 12:59:17 -0300607/* tcp.c */
Eric Dumazet0df48c22015-04-28 15:28:17 -0700608void tcp_get_info(struct sock *, struct tcp_info *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609
610/* Read 'sendfile()'-style from a TCP socket */
Joe Perches5c9f3022013-09-23 11:33:32 -0700611int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
612 sk_read_actor_t recv_actor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613
Joe Perches5c9f3022013-09-23 11:33:32 -0700614void tcp_initialize_rcv_mss(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615
Joe Perches5c9f3022013-09-23 11:33:32 -0700616int tcp_mtu_to_mss(struct sock *sk, int pmtu);
617int tcp_mss_to_mtu(struct sock *sk, int mss);
618void tcp_mtup_init(struct sock *sk);
619void tcp_init_buffer_space(struct sock *sk);
John Heffner5d424d52006-03-20 17:53:41 -0800620
Damian Lukowskif1ecd5d2009-08-26 00:16:31 +0000621static inline void tcp_bound_rto(const struct sock *sk)
622{
623 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
624 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
625}
626
627static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
628{
Eric Dumazet740b0f12014-02-26 14:02:48 -0800629 return usecs_to_jiffies((tp->srtt_us >> 3) + tp->rttvar_us);
Damian Lukowskif1ecd5d2009-08-26 00:16:31 +0000630}
631
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800632static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
634 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
635 ntohl(TCP_FLAG_ACK) |
636 snd_wnd);
637}
638
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800639static inline void tcp_fast_path_on(struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640{
641 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
642}
643
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700644static inline void tcp_fast_path_check(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645{
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700646 struct tcp_sock *tp = tcp_sk(sk);
647
Yaogong Wang9f5afea2016-09-07 14:49:28 -0700648 if (RB_EMPTY_ROOT(&tp->out_of_order_queue) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 tp->rcv_wnd &&
650 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
651 !tp->urg_data)
652 tcp_fast_path_on(tp);
653}
654
Satoru SATOH0c266892009-05-04 11:11:01 -0700655/* Compute the actual rto_min value */
656static inline u32 tcp_rto_min(struct sock *sk)
657{
Eric Dumazetcf533ea2011-10-21 05:22:42 -0400658 const struct dst_entry *dst = __sk_dst_get(sk);
Satoru SATOH0c266892009-05-04 11:11:01 -0700659 u32 rto_min = TCP_RTO_MIN;
660
661 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
662 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
663 return rto_min;
664}
665
Eric Dumazet740b0f12014-02-26 14:02:48 -0800666static inline u32 tcp_rto_min_us(struct sock *sk)
667{
668 return jiffies_to_usecs(tcp_rto_min(sk));
669}
670
Daniel Borkmann81164412015-01-05 23:57:48 +0100671static inline bool tcp_ca_dst_locked(const struct dst_entry *dst)
672{
673 return dst_metric_locked(dst, RTAX_CC_ALGO);
674}
675
Yuchung Chengf6722582015-10-16 21:57:42 -0700676/* Minimum RTT in usec. ~0 means not available. */
677static inline u32 tcp_min_rtt(const struct tcp_sock *tp)
678{
Neal Cardwell64033892016-09-19 23:39:10 -0400679 return minmax_get(&tp->rtt_min);
Yuchung Chengf6722582015-10-16 21:57:42 -0700680}
681
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682/* Compute the actual receive window we are currently advertising.
683 * Rcv_nxt can be after the window if our peer push more data
684 * than the offered window.
685 */
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800686static inline u32 tcp_receive_window(const struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687{
688 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
689
690 if (win < 0)
691 win = 0;
692 return (u32) win;
693}
694
695/* Choose a new window, without checks for shrinking, and without
696 * scaling applied to the result. The caller does these things
697 * if necessary. This is a "raw" window selection.
698 */
Joe Perches5c9f3022013-09-23 11:33:32 -0700699u32 __tcp_select_window(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700
Pavel Emelyanovee995282012-04-19 03:40:39 +0000701void tcp_send_window_probe(struct sock *sk);
702
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703/* TCP timestamps are only 32-bits, this causes a slight
704 * complication on 64-bit systems since we store a snapshot
Stephen Hemminger31f34262005-11-15 15:17:10 -0800705 * of jiffies in the buffer control blocks below. We decided
706 * to use only the low 32-bits of jiffies and hide the ugly
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 * casts with the following macro.
708 */
709#define tcp_time_stamp ((__u32)(jiffies))
710
Eric Dumazet7faee5c2014-09-05 15:33:33 -0700711static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
712{
713 return skb->skb_mstamp.stamp_jiffies;
714}
715
716
Changli Gaoa3433f32010-06-12 14:01:43 +0000717#define tcp_flag_byte(th) (((u_int8_t *)th)[13])
718
719#define TCPHDR_FIN 0x01
720#define TCPHDR_SYN 0x02
721#define TCPHDR_RST 0x04
722#define TCPHDR_PSH 0x08
723#define TCPHDR_ACK 0x10
724#define TCPHDR_URG 0x20
725#define TCPHDR_ECE 0x40
726#define TCPHDR_CWR 0x80
727
Daniel Borkmann49213552015-05-19 21:04:22 +0200728#define TCPHDR_SYN_ECN (TCPHDR_SYN | TCPHDR_ECE | TCPHDR_CWR)
729
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -0800730/* This is what the send packet queuing engine uses to pass
Eric Dumazetf86586f2010-07-15 21:41:00 -0700731 * TCP per-packet control information to the transmission code.
732 * We also store the host-order sequence numbers in here too.
733 * This is 44 bytes if IPV6 is enabled.
734 * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 */
736struct tcp_skb_cb {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 __u32 seq; /* Starting sequence number */
738 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
Eric Dumazetcd7d8492014-09-24 04:11:22 -0700739 union {
740 /* Note : tcp_tw_isn is used in input path only
741 * (isn chosen by tcp_timewait_state_process())
742 *
Eric Dumazetf69ad292015-06-11 09:15:18 -0700743 * tcp_gso_segs/size are used in write queue only,
744 * cf tcp_skb_pcount()/tcp_skb_mss()
Eric Dumazetcd7d8492014-09-24 04:11:22 -0700745 */
746 __u32 tcp_tw_isn;
Eric Dumazetf69ad292015-06-11 09:15:18 -0700747 struct {
748 u16 tcp_gso_segs;
749 u16 tcp_gso_size;
750 };
Eric Dumazetcd7d8492014-09-24 04:11:22 -0700751 };
Eric Dumazet4de075e2011-09-27 13:25:05 -0400752 __u8 tcp_flags; /* TCP header flags. (tcp[13]) */
Neal Cardwellf4f9f6e2012-04-16 07:08:06 +0000753
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 __u8 sacked; /* State flags for SACK/FACK. */
755#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
756#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
757#define TCPCB_LOST 0x04 /* SKB is lost */
758#define TCPCB_TAGBITS 0x07 /* All tag bits */
Andrey Vagin9d186ca2014-08-13 16:03:10 +0400759#define TCPCB_REPAIRED 0x10 /* SKB repaired (no skb_mstamp) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
Andrey Vagin9d186ca2014-08-13 16:03:10 +0400761#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
762 TCPCB_REPAIRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
Neal Cardwellf4f9f6e2012-04-16 07:08:06 +0000764 __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
Soheil Hassas Yeganeh6b084922016-04-02 23:08:08 -0400765 __u8 txstamp_ack:1, /* Record TX timestamp for ack? */
Martin KaFai Lauc134ecb2016-04-25 14:44:48 -0700766 eor:1, /* Is skb MSG_EOR marked? */
767 unused:6;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 __u32 ack_seq; /* Sequence number ACK'd */
Eric Dumazet971f10e2014-09-27 09:50:57 -0700769 union {
Lawrence Brakmob75803d2016-05-06 20:35:35 -0700770 struct {
Yuchung Chengb9f64822016-09-19 23:39:14 -0400771 /* There is space for up to 24 bytes */
Soheil Hassas Yeganehd7722e82016-09-19 23:39:15 -0400772 __u32 in_flight:30,/* Bytes in flight at transmit */
773 is_app_limited:1, /* cwnd not fully used? */
774 unused:1;
Yuchung Chengb9f64822016-09-19 23:39:14 -0400775 /* pkts S/ACKed so far upon tx of skb, incl retrans: */
776 __u32 delivered;
777 /* start of send pipeline phase */
778 struct skb_mstamp first_tx_mstamp;
779 /* when we reached the "delivered" count */
780 struct skb_mstamp delivered_mstamp;
Lawrence Brakmob75803d2016-05-06 20:35:35 -0700781 } tx; /* only used for outgoing skbs */
782 union {
783 struct inet_skb_parm h4;
Eric Dumazet971f10e2014-09-27 09:50:57 -0700784#if IS_ENABLED(CONFIG_IPV6)
Lawrence Brakmob75803d2016-05-06 20:35:35 -0700785 struct inet6_skb_parm h6;
Eric Dumazet971f10e2014-09-27 09:50:57 -0700786#endif
Lawrence Brakmob75803d2016-05-06 20:35:35 -0700787 } header; /* For incoming skbs */
788 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789};
790
791#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
792
Eric Dumazet870c3152014-10-17 09:17:20 -0700793
Eric Dumazet815afe12014-10-18 08:34:37 -0700794#if IS_ENABLED(CONFIG_IPV6)
Eric Dumazet870c3152014-10-17 09:17:20 -0700795/* This is the variant of inet6_iif() that must be used by TCP,
796 * as TCP moves IP6CB into a different location in skb->cb[]
797 */
798static inline int tcp_v6_iif(const struct sk_buff *skb)
799{
David Aherna04a4802016-10-16 20:02:52 -0700800 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
David Ahern74b20582016-05-10 11:19:50 -0700801
802 return l3_slave ? skb->skb_iif : TCP_SKB_CB(skb)->header.h6.iif;
Eric Dumazet870c3152014-10-17 09:17:20 -0700803}
Eric Dumazet815afe12014-10-18 08:34:37 -0700804#endif
Eric Dumazet870c3152014-10-17 09:17:20 -0700805
David Aherna04a4802016-10-16 20:02:52 -0700806/* TCP_SKB_CB reference means this can not be used from early demux */
807static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb)
808{
809#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
810 if (!net->ipv4.sysctl_tcp_l3mdev_accept &&
David Ahernda967862016-11-02 12:08:25 -0700811 skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
David Aherna04a4802016-10-16 20:02:52 -0700812 return true;
813#endif
814 return false;
815}
816
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817/* Due to TSO, an SKB can be composed of multiple actual
818 * packets. To keep these tracked properly, we use this.
819 */
820static inline int tcp_skb_pcount(const struct sk_buff *skb)
821{
Eric Dumazetcd7d8492014-09-24 04:11:22 -0700822 return TCP_SKB_CB(skb)->tcp_gso_segs;
823}
824
825static inline void tcp_skb_pcount_set(struct sk_buff *skb, int segs)
826{
827 TCP_SKB_CB(skb)->tcp_gso_segs = segs;
828}
829
830static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs)
831{
832 TCP_SKB_CB(skb)->tcp_gso_segs += segs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833}
834
Eric Dumazetf69ad292015-06-11 09:15:18 -0700835/* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836static inline int tcp_skb_mss(const struct sk_buff *skb)
837{
Eric Dumazetf69ad292015-06-11 09:15:18 -0700838 return TCP_SKB_CB(skb)->tcp_gso_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839}
840
Martin KaFai Lauc134ecb2016-04-25 14:44:48 -0700841static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb)
842{
843 return likely(!TCP_SKB_CB(skb)->eor);
844}
845
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700846/* Events passed to congestion control interface */
847enum tcp_ca_event {
848 CA_EVENT_TX_START, /* first transmit when no packets in flight */
849 CA_EVENT_CWND_RESTART, /* congestion window restart */
850 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700851 CA_EVENT_LOSS, /* loss timeout */
Florian Westphal98900922014-09-26 22:37:35 +0200852 CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
853 CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
854 CA_EVENT_DELAYED_ACK, /* Delayed ack is sent */
855 CA_EVENT_NON_DELAYED_ACK,
Florian Westphal7354c8c2014-09-26 22:37:34 +0200856};
857
Florian Westphal98900922014-09-26 22:37:35 +0200858/* Information about inbound ACK, passed to cong_ops->in_ack_event() */
Florian Westphal7354c8c2014-09-26 22:37:34 +0200859enum tcp_ca_ack_event_flags {
Florian Westphal98900922014-09-26 22:37:35 +0200860 CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */
861 CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */
862 CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700863};
864
865/*
866 * Interface for adding new TCP congestion control handlers
867 */
868#define TCP_CA_NAME_MAX 16
Stephen Hemminger3ff825b2006-11-09 16:32:06 -0800869#define TCP_CA_MAX 128
870#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
871
Daniel Borkmannc5c6a8a2015-01-05 23:57:46 +0100872#define TCP_CA_UNSPEC 0
873
Daniel Borkmann30e502a2014-09-26 22:37:33 +0200874/* Algorithm can be set on socket without CAP_NET_ADMIN privileges */
Stephen Hemminger164891a2007-04-23 22:26:16 -0700875#define TCP_CONG_NON_RESTRICTED 0x1
Daniel Borkmann30e502a2014-09-26 22:37:33 +0200876/* Requires ECN/ECT set on all packets */
877#define TCP_CONG_NEEDS_ECN 0x2
Stephen Hemminger164891a2007-04-23 22:26:16 -0700878
Eric Dumazet64f40ff2015-04-28 16:23:48 -0700879union tcp_cc_info;
880
Lawrence Brakmo756ee172016-05-11 10:02:13 -0700881struct ack_sample {
882 u32 pkts_acked;
883 s32 rtt_us;
Lawrence Brakmo6f094b92016-06-08 21:16:44 -0700884 u32 in_flight;
Lawrence Brakmo756ee172016-05-11 10:02:13 -0700885};
886
Yuchung Chengb9f64822016-09-19 23:39:14 -0400887/* A rate sample measures the number of (original/retransmitted) data
888 * packets delivered "delivered" over an interval of time "interval_us".
889 * The tcp_rate.c code fills in the rate sample, and congestion
890 * control modules that define a cong_control function to run at the end
891 * of ACK processing can optionally chose to consult this sample when
892 * setting cwnd and pacing rate.
893 * A sample is invalid if "delivered" or "interval_us" is negative.
894 */
895struct rate_sample {
896 struct skb_mstamp prior_mstamp; /* starting timestamp for interval */
897 u32 prior_delivered; /* tp->delivered at "prior_mstamp" */
898 s32 delivered; /* number of packets delivered over interval */
899 long interval_us; /* time for tp->delivered to incr "delivered" */
900 long rtt_us; /* RTT of last (S)ACKed packet (or -1) */
901 int losses; /* number of packets marked lost upon ACK */
902 u32 acked_sacked; /* number of packets newly (S)ACKed upon ACK */
903 u32 prior_in_flight; /* in flight before this ACK */
Soheil Hassas Yeganehd7722e82016-09-19 23:39:15 -0400904 bool is_app_limited; /* is sample from packet with bubble in pipe? */
Yuchung Chengb9f64822016-09-19 23:39:14 -0400905 bool is_retrans; /* is sample from retransmission? */
906};
907
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700908struct tcp_congestion_ops {
909 struct list_head list;
Daniel Borkmannc5c6a8a2015-01-05 23:57:46 +0100910 u32 key;
911 u32 flags;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700912
913 /* initialize private data (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300914 void (*init)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700915 /* cleanup private data (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300916 void (*release)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700917
918 /* return slow start threshold (required) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300919 u32 (*ssthresh)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700920 /* do new cwnd calculation (required) */
Eric Dumazet24901552014-05-02 21:18:05 -0700921 void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700922 /* call before changing ca_state (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300923 void (*set_state)(struct sock *sk, u8 new_state);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700924 /* call when cwnd event occurs (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300925 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
Florian Westphal7354c8c2014-09-26 22:37:34 +0200926 /* call when ack arrives (optional) */
927 void (*in_ack_event)(struct sock *sk, u32 flags);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700928 /* new value of cwnd after loss (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300929 u32 (*undo_cwnd)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700930 /* hook for packet ack accounting (optional) */
Lawrence Brakmo756ee172016-05-11 10:02:13 -0700931 void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);
Neal Cardwelled6e7262016-09-19 23:39:17 -0400932 /* suggest number of segments for each skb to transmit (optional) */
933 u32 (*tso_segs_goal)(struct sock *sk);
Yuchung Cheng77bfc172016-09-19 23:39:20 -0400934 /* returns the multiplier used in tcp_sndbuf_expand (optional) */
935 u32 (*sndbuf_expand)(struct sock *sk);
Yuchung Chengc0402762016-09-19 23:39:21 -0400936 /* call when packets are delivered to update cwnd and pacing rate,
937 * after all the ca_state processing. (optional)
938 */
939 void (*cong_control)(struct sock *sk, const struct rate_sample *rs);
Arnaldo Carvalho de Melo73c1f4a2005-08-12 12:51:49 -0300940 /* get info for inet_diag (optional) */
Eric Dumazet64f40ff2015-04-28 16:23:48 -0700941 size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
942 union tcp_cc_info *info);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700943
944 char name[TCP_CA_NAME_MAX];
945 struct module *owner;
946};
947
Joe Perches5c9f3022013-09-23 11:33:32 -0700948int tcp_register_congestion_control(struct tcp_congestion_ops *type);
949void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700950
Florian Westphal55d86942014-09-26 22:37:32 +0200951void tcp_assign_congestion_control(struct sock *sk);
Joe Perches5c9f3022013-09-23 11:33:32 -0700952void tcp_init_congestion_control(struct sock *sk);
953void tcp_cleanup_congestion_control(struct sock *sk);
954int tcp_set_default_congestion_control(const char *name);
955void tcp_get_default_congestion_control(char *name);
956void tcp_get_available_congestion_control(char *buf, size_t len);
957void tcp_get_allowed_congestion_control(char *buf, size_t len);
958int tcp_set_allowed_congestion_control(char *allowed);
959int tcp_set_congestion_control(struct sock *sk, const char *name);
Neal Cardwelle73ebb082015-01-28 20:01:35 -0500960u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
961void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700962
Joe Perches5c9f3022013-09-23 11:33:32 -0700963u32 tcp_reno_ssthresh(struct sock *sk);
Florian Westphale9799182016-11-21 14:18:38 +0100964u32 tcp_reno_undo_cwnd(struct sock *sk);
Eric Dumazet24901552014-05-02 21:18:05 -0700965void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked);
David S. Millera8acfba2005-06-23 23:45:02 -0700966extern struct tcp_congestion_ops tcp_reno;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700967
Daniel Borkmannc5c6a8a2015-01-05 23:57:46 +0100968struct tcp_congestion_ops *tcp_ca_find_key(u32 key);
Daniel Borkmannc3a8d942015-08-31 15:58:47 +0200969u32 tcp_ca_get_key_by_name(const char *name, bool *ecn_ca);
Daniel Borkmannea697632015-01-05 23:57:47 +0100970#ifdef CONFIG_INET
Daniel Borkmannc5c6a8a2015-01-05 23:57:46 +0100971char *tcp_ca_get_name_by_key(u32 key, char *buffer);
Daniel Borkmannea697632015-01-05 23:57:47 +0100972#else
973static inline char *tcp_ca_get_name_by_key(u32 key, char *buffer)
974{
975 return NULL;
976}
977#endif
Daniel Borkmannc5c6a8a2015-01-05 23:57:46 +0100978
Daniel Borkmann30e502a2014-09-26 22:37:33 +0200979static inline bool tcp_ca_needs_ecn(const struct sock *sk)
980{
981 const struct inet_connection_sock *icsk = inet_csk(sk);
982
983 return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
984}
985
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300986static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700987{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300988 struct inet_connection_sock *icsk = inet_csk(sk);
989
990 if (icsk->icsk_ca_ops->set_state)
991 icsk->icsk_ca_ops->set_state(sk, ca_state);
992 icsk->icsk_ca_state = ca_state;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700993}
994
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300995static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700996{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300997 const struct inet_connection_sock *icsk = inet_csk(sk);
998
999 if (icsk->icsk_ca_ops->cwnd_event)
1000 icsk->icsk_ca_ops->cwnd_event(sk, event);
Stephen Hemminger317a76f2005-06-23 12:19:55 -07001001}
1002
Yuchung Chengb9f64822016-09-19 23:39:14 -04001003/* From tcp_rate.c */
1004void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
1005void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
1006 struct rate_sample *rs);
1007void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
Eric Dumazet88d5c652017-04-25 10:15:37 -07001008 struct rate_sample *rs);
Soheil Hassas Yeganehd7722e82016-09-19 23:39:15 -04001009void tcp_rate_check_app_limited(struct sock *sk);
Yuchung Chengb9f64822016-09-19 23:39:14 -04001010
Ilpo Järvinene60402d2007-08-09 15:14:46 +03001011/* These functions determine how the current flow behaves in respect of SACK
1012 * handling. SACK is negotiated with the peer, and therefore it can vary
1013 * between different flows.
1014 *
1015 * tcp_is_sack - SACK enabled
1016 * tcp_is_reno - No SACK
1017 * tcp_is_fack - FACK enabled, implies SACK enabled
1018 */
1019static inline int tcp_is_sack(const struct tcp_sock *tp)
1020{
1021 return tp->rx_opt.sack_ok;
1022}
1023
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001024static inline bool tcp_is_reno(const struct tcp_sock *tp)
Ilpo Järvinene60402d2007-08-09 15:14:46 +03001025{
1026 return !tcp_is_sack(tp);
1027}
1028
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001029static inline bool tcp_is_fack(const struct tcp_sock *tp)
Ilpo Järvinene60402d2007-08-09 15:14:46 +03001030{
Vijay Subramanianab562222011-12-20 13:23:24 +00001031 return tp->rx_opt.sack_ok & TCP_FACK_ENABLED;
Ilpo Järvinene60402d2007-08-09 15:14:46 +03001032}
1033
1034static inline void tcp_enable_fack(struct tcp_sock *tp)
1035{
Vijay Subramanianab562222011-12-20 13:23:24 +00001036 tp->rx_opt.sack_ok |= TCP_FACK_ENABLED;
Ilpo Järvinene60402d2007-08-09 15:14:46 +03001037}
1038
Ilpo Järvinen83ae4082007-08-09 14:37:30 +03001039static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
1040{
1041 return tp->sacked_out + tp->lost_out;
1042}
1043
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044/* This determines how many packets are "in the network" to the best
1045 * of our knowledge. In many cases it is conservative, but where
1046 * detailed information is available from the receiver (via SACK
1047 * blocks etc.) we can make more aggressive calculations.
1048 *
1049 * Use this for decisions involving congestion control, use just
1050 * tp->packets_out to determine if the send queue is empty or not.
1051 *
1052 * Read this equation as:
1053 *
1054 * "Packets sent once on transmission queue" MINUS
1055 * "Packets left network, but not honestly ACKed yet" PLUS
1056 * "Packets fast retransmitted"
1057 */
Stephen Hemminger40efc6f2006-01-03 16:03:49 -08001058static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059{
Ilpo Järvinen83ae4082007-08-09 14:37:30 +03001060 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061}
1062
Ilpo Järvinen0b6a05c2009-09-15 01:30:10 -07001063#define TCP_INFINITE_SSTHRESH 0x7fffffff
1064
Yuchung Cheng071d5082015-07-09 13:16:29 -07001065static inline bool tcp_in_slow_start(const struct tcp_sock *tp)
1066{
Yuchung Cheng76174002015-07-09 13:16:30 -07001067 return tp->snd_cwnd < tp->snd_ssthresh;
Yuchung Cheng071d5082015-07-09 13:16:29 -07001068}
1069
Ilpo Järvinen0b6a05c2009-09-15 01:30:10 -07001070static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
1071{
1072 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
1073}
1074
Yuchung Cheng684bad12012-09-02 17:38:04 +00001075static inline bool tcp_in_cwnd_reduction(const struct sock *sk)
1076{
1077 return (TCPF_CA_CWR | TCPF_CA_Recovery) &
1078 (1 << inet_csk(sk)->icsk_ca_state);
1079}
1080
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
Yuchung Cheng684bad12012-09-02 17:38:04 +00001082 * The exception is cwnd reduction phase, when cwnd is decreasing towards
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 * ssthresh.
1084 */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -03001085static inline __u32 tcp_current_ssthresh(const struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -03001087 const struct tcp_sock *tp = tcp_sk(sk);
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001088
Yuchung Cheng684bad12012-09-02 17:38:04 +00001089 if (tcp_in_cwnd_reduction(sk))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 return tp->snd_ssthresh;
1091 else
1092 return max(tp->snd_ssthresh,
1093 ((tp->snd_cwnd >> 1) +
1094 (tp->snd_cwnd >> 2)));
1095}
1096
Ilpo Järvinenb9c45952007-07-27 16:36:17 +03001097/* Use define here intentionally to get WARN_ON location shown at the caller */
1098#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
Christoph Paasch5ee2c942014-07-14 16:58:32 +02001100void tcp_enter_cwr(struct sock *sk);
Joe Perches5c9f3022013-09-23 11:33:32 -07001101__u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102
Neal Cardwell6b5a5c02011-11-21 17:15:14 +00001103/* The maximum number of MSS of available cwnd for which TSO defers
1104 * sending if not using sysctl_tcp_tso_win_divisor.
1105 */
1106static inline __u32 tcp_max_tso_deferred_mss(const struct tcp_sock *tp)
1107{
1108 return 3;
1109}
1110
Ilpo Järvinen90840de2007-12-31 04:48:41 -08001111/* Returns end sequence number of the receiver's advertised window */
1112static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
1113{
1114 return tp->snd_una + tp->snd_wnd;
1115}
Eric Dumazete114a712014-04-30 11:58:13 -07001116
1117/* We follow the spirit of RFC2861 to validate cwnd but implement a more
1118 * flexible approach. The RFC suggests cwnd should not be raised unless
Neal Cardwellca8a2262014-05-22 10:41:08 -04001119 * it was fully used previously. And that's exactly what we do in
1120 * congestion avoidance mode. But in slow start we allow cwnd to grow
1121 * as long as the application has used half the cwnd.
Eric Dumazete114a712014-04-30 11:58:13 -07001122 * Example :
1123 * cwnd is 10 (IW10), but application sends 9 frames.
1124 * We allow cwnd to reach 18 when all frames are ACKed.
1125 * This check is safe because it's as aggressive as slow start which already
1126 * risks 100% overshoot. The advantage is that we discourage application to
1127 * either send more filler packets or data to artificially blow up the cwnd
1128 * usage, and allow application-limited process to probe bw more aggressively.
Eric Dumazete114a712014-04-30 11:58:13 -07001129 */
Eric Dumazet24901552014-05-02 21:18:05 -07001130static inline bool tcp_is_cwnd_limited(const struct sock *sk)
Eric Dumazete114a712014-04-30 11:58:13 -07001131{
1132 const struct tcp_sock *tp = tcp_sk(sk);
1133
Neal Cardwellca8a2262014-05-22 10:41:08 -04001134 /* If in slow start, ensure cwnd grows to twice what was ACKed. */
Yuchung Cheng071d5082015-07-09 13:16:29 -07001135 if (tcp_in_slow_start(tp))
Neal Cardwellca8a2262014-05-22 10:41:08 -04001136 return tp->snd_cwnd < 2 * tp->max_packets_out;
1137
1138 return tp->is_cwnd_limited;
Eric Dumazete114a712014-04-30 11:58:13 -07001139}
Stephen Hemmingerf4805ed2005-11-10 16:53:30 -08001140
Eric Dumazet21c8fe92015-05-06 14:26:24 -07001141/* Something is really bad, we could not queue an additional packet,
1142 * because qdisc is full or receiver sent a 0 window.
1143 * We do not want to add fuel to the fire, or abort too early,
1144 * so make sure the timer we arm now is at least 200ms in the future,
1145 * regardless of current icsk_rto value (as it could be ~2ms)
1146 */
1147static inline unsigned long tcp_probe0_base(const struct sock *sk)
1148{
1149 return max_t(unsigned long, inet_csk(sk)->icsk_rto, TCP_RTO_MIN);
1150}
1151
1152/* Variant of inet_csk_rto_backoff() used for zero window probes */
1153static inline unsigned long tcp_probe0_when(const struct sock *sk,
1154 unsigned long max_when)
1155{
1156 u64 when = (u64)tcp_probe0_base(sk) << inet_csk(sk)->icsk_backoff;
1157
1158 return (unsigned long)min_t(u64, when, max_when);
1159}
1160
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -07001161static inline void tcp_check_probe_timer(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162{
Eric Dumazet21c8fe92015-05-06 14:26:24 -07001163 if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending)
Arnaldo Carvalho de Melo3f421ba2005-08-09 20:11:08 -07001164 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
Eric Dumazet21c8fe92015-05-06 14:26:24 -07001165 tcp_probe0_base(sk), TCP_RTO_MAX);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166}
1167
Hantzis Fotisee7537b2009-03-02 22:42:02 -08001168static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169{
1170 tp->snd_wl1 = seq;
1171}
1172
Hantzis Fotisee7537b2009-03-02 22:42:02 -08001173static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174{
1175 tp->snd_wl1 = seq;
1176}
1177
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178/*
1179 * Calculate(/check) TCP checksum
1180 */
Frederik Deweerdtba7808e2007-02-04 20:15:27 -08001181static inline __sum16 tcp_v4_check(int len, __be32 saddr,
1182 __be32 daddr, __wsum base)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183{
1184 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
1185}
1186
Al Virob51655b2006-11-14 21:40:42 -08001187static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188{
Herbert Xufb286bb2005-11-10 13:01:24 -08001189 return __skb_checksum_complete(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190}
1191
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001192static inline bool tcp_checksum_complete(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193{
Herbert Xu60476372007-04-09 11:59:39 -07001194 return !skb_csum_unnecessary(skb) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 __tcp_checksum_complete(skb);
1196}
1197
1198/* Prequeue for VJ style copy to user, combined with checksumming. */
1199
Stephen Hemminger40efc6f2006-01-03 16:03:49 -08001200static inline void tcp_prequeue_init(struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201{
1202 tp->ucopy.task = NULL;
1203 tp->ucopy.len = 0;
1204 tp->ucopy.memory = 0;
1205 skb_queue_head_init(&tp->ucopy.prequeue);
1206}
1207
Joe Perches5c9f3022013-09-23 11:33:32 -07001208bool tcp_prequeue(struct sock *sk, struct sk_buff *skb);
Eric Dumazetc9c33212016-08-27 07:37:54 -07001209bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb);
Eric Dumazetac6e7802016-11-10 13:12:35 -08001210int tcp_filter(struct sock *sk, struct sk_buff *skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211
1212#undef STATE_TRACE
1213
1214#ifdef STATE_TRACE
1215static const char *statename[]={
1216 "Unused","Established","Syn Sent","Syn Recv",
1217 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
1218 "Close Wait","Last ACK","Listen","Closing"
1219};
1220#endif
Joe Perches5c9f3022013-09-23 11:33:32 -07001221void tcp_set_state(struct sock *sk, int state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222
Joe Perches5c9f3022013-09-23 11:33:32 -07001223void tcp_done(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224
Lorenzo Colittic1e64e22015-12-16 12:30:05 +09001225int tcp_abort(struct sock *sk, int err);
1226
Stephen Hemminger40efc6f2006-01-03 16:03:49 -08001227static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228{
1229 rx_opt->dsack = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 rx_opt->num_sacks = 0;
1231}
1232
Joe Perches5c9f3022013-09-23 11:33:32 -07001233u32 tcp_default_init_rwnd(u32 mss);
Eric Dumazet6f021c62015-08-21 12:30:00 -07001234void tcp_cwnd_restart(struct sock *sk, s32 delta);
1235
1236static inline void tcp_slow_start_after_idle_check(struct sock *sk)
1237{
Wei Wang1b1fc3f2017-05-05 12:53:23 -07001238 const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
Eric Dumazet6f021c62015-08-21 12:30:00 -07001239 struct tcp_sock *tp = tcp_sk(sk);
1240 s32 delta;
1241
Wei Wang1b1fc3f2017-05-05 12:53:23 -07001242 if (!sysctl_tcp_slow_start_after_idle || tp->packets_out ||
1243 ca_ops->cong_control)
Eric Dumazet6f021c62015-08-21 12:30:00 -07001244 return;
1245 delta = tcp_time_stamp - tp->lsndtime;
1246 if (delta > inet_csk(sk)->icsk_rto)
1247 tcp_cwnd_restart(sk, delta);
1248}
Yuchung Cheng85f16522013-06-11 15:35:32 -07001249
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250/* Determine a window scaling and initial window to offer. */
Joe Perches5c9f3022013-09-23 11:33:32 -07001251void tcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
1252 __u32 *window_clamp, int wscale_ok,
1253 __u8 *rcv_wscale, __u32 init_rcv_wnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254
1255static inline int tcp_win_from_space(int space)
1256{
Gao Fengc4836742017-03-24 07:05:12 +08001257 int tcp_adv_win_scale = sysctl_tcp_adv_win_scale;
1258
1259 return tcp_adv_win_scale <= 0 ?
1260 (space>>(-tcp_adv_win_scale)) :
1261 space - (space>>tcp_adv_win_scale);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262}
1263
Kenjiro Nakayama105970f2014-10-20 18:15:50 +09001264/* Note: caller must be prepared to deal with negative returns */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265static inline int tcp_space(const struct sock *sk)
1266{
1267 return tcp_win_from_space(sk->sk_rcvbuf -
1268 atomic_read(&sk->sk_rmem_alloc));
Kenjiro Nakayama105970f2014-10-20 18:15:50 +09001269}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270
1271static inline int tcp_full_space(const struct sock *sk)
1272{
Kenjiro Nakayama105970f2014-10-20 18:15:50 +09001273 return tcp_win_from_space(sk->sk_rcvbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274}
1275
Yuchung Cheng843f4a52014-05-11 20:22:11 -07001276extern void tcp_openreq_init_rwin(struct request_sock *req,
Eric Dumazetb1964b52015-09-25 07:39:09 -07001277 const struct sock *sk_listener,
1278 const struct dst_entry *dst);
Yuchung Cheng843f4a52014-05-11 20:22:11 -07001279
Joe Perches5c9f3022013-09-23 11:33:32 -07001280void tcp_enter_memory_pressure(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1283{
Nikolay Borisovb840d152016-01-07 16:38:45 +02001284 struct net *net = sock_net((struct sock *)tp);
1285
1286 return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287}
1288
1289static inline int keepalive_time_when(const struct tcp_sock *tp)
1290{
Nikolay Borisov13b287e2016-01-07 16:38:43 +02001291 struct net *net = sock_net((struct sock *)tp);
1292
1293 return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294}
1295
Eric Dumazetdf19a622009-08-28 23:48:54 -07001296static inline int keepalive_probes(const struct tcp_sock *tp)
1297{
Nikolay Borisov9bd68612016-01-07 16:38:44 +02001298 struct net *net = sock_net((struct sock *)tp);
1299
1300 return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes;
Eric Dumazetdf19a622009-08-28 23:48:54 -07001301}
1302
Flavio Leitner6c37e5d2010-04-26 18:33:27 +00001303static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
1304{
1305 const struct inet_connection_sock *icsk = &tp->inet_conn;
1306
1307 return min_t(u32, tcp_time_stamp - icsk->icsk_ack.lrcvtime,
1308 tcp_time_stamp - tp->rcv_tstamp);
1309}
1310
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001311static inline int tcp_fin_time(const struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312{
Nikolay Borisov1e579ca2016-02-03 09:46:56 +02001313 int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout;
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001314 const int rto = inet_csk(sk)->icsk_rto;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001316 if (fin_timeout < (rto << 2) - (rto >> 1))
1317 fin_timeout = (rto << 2) - (rto >> 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318
1319 return fin_timeout;
1320}
1321
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001322static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt,
1323 int paws_win)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324{
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001325 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001326 return true;
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001327 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001328 return true;
Eric Dumazetbc2ce892010-12-16 14:08:34 -08001329 /*
1330 * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0,
1331 * then following tcp messages have valid values. Ignore 0 value,
1332 * or else 'negative' tsval might forbid us to accept their packets.
1333 */
1334 if (!rx_opt->ts_recent)
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001335 return true;
1336 return false;
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001337}
1338
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001339static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
1340 int rst)
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001341{
1342 if (tcp_paws_check(rx_opt, 0))
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001343 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344
1345 /* RST segments are not recommended to carry timestamp,
1346 and, if they do, it is recommended to ignore PAWS because
1347 "their cleanup function should take precedence over timestamps."
1348 Certainly, it is mistake. It is necessary to understand the reasons
1349 of this constraint to relax it: if peer reboots, clock may go
1350 out-of-sync and half-open connections will not be reset.
1351 Actually, the problem would be not existing if all
1352 the implementations followed draft about maintaining clock
1353 via reboots. Linux-2.2 DOES NOT!
1354
1355 However, we can relax time bounds for RST segments to MSL.
1356 */
James Morris9d729f72007-03-04 16:12:44 -08001357 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001358 return false;
1359 return true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360}
1361
Eric Dumazet7970ddc2015-03-16 21:06:20 -07001362bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
1363 int mib_idx, u32 *last_oow_ack_time);
Neal Cardwell032ee422015-02-06 16:04:38 -05001364
Pavel Emelyanova9c193292008-07-16 20:21:42 -07001365static inline void tcp_mib_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366{
1367 /* See RFC 2012 */
Eric Dumazet6aef70a2016-04-27 16:44:27 -07001368 TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1);
1369 TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1370 TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1371 TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372}
1373
Ilpo Järvinen5af4ec22007-09-20 11:30:48 -07001374/* from STCP */
Ilpo Järvinenef9da472008-09-20 21:25:15 -07001375static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
David S. Miller0800f172007-09-20 11:40:37 -07001376{
Stephen Hemminger6a438bb2005-11-10 17:14:59 -08001377 tp->lost_skb_hint = NULL;
Ilpo Järvinenef9da472008-09-20 21:25:15 -07001378}
1379
1380static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1381{
1382 tcp_clear_retrans_hints_partial(tp);
Stephen Hemminger6a438bb2005-11-10 17:14:59 -08001383 tp->retransmit_skb_hint = NULL;
Ilpo Järvinenb7689202007-09-20 11:37:19 -07001384}
1385
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001386union tcp_md5_addr {
1387 struct in_addr a4;
1388#if IS_ENABLED(CONFIG_IPV6)
1389 struct in6_addr a6;
1390#endif
1391};
1392
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001393/* - key database */
1394struct tcp_md5sig_key {
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001395 struct hlist_node node;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001396 u8 keylen;
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001397 u8 family; /* AF_INET or AF_INET6 */
1398 union tcp_md5_addr addr;
1399 u8 key[TCP_MD5SIG_MAXKEYLEN];
1400 struct rcu_head rcu;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001401};
1402
1403/* - sock block */
1404struct tcp_md5sig_info {
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001405 struct hlist_head head;
Eric Dumazeta8afca02012-01-31 18:45:40 +00001406 struct rcu_head rcu;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001407};
1408
1409/* - pseudo header */
1410struct tcp4_pseudohdr {
1411 __be32 saddr;
1412 __be32 daddr;
1413 __u8 pad;
1414 __u8 protocol;
1415 __be16 len;
1416};
1417
1418struct tcp6_pseudohdr {
1419 struct in6_addr saddr;
1420 struct in6_addr daddr;
1421 __be32 len;
1422 __be32 protocol; /* including padding */
1423};
1424
1425union tcp_md5sum_block {
1426 struct tcp4_pseudohdr ip4;
Eric Dumazetdfd56b82011-12-10 09:48:31 +00001427#if IS_ENABLED(CONFIG_IPV6)
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001428 struct tcp6_pseudohdr ip6;
1429#endif
1430};
1431
1432/* - pool: digest algorithm, hash description and scratch buffer */
1433struct tcp_md5sig_pool {
Herbert Xucf80e0e2016-01-24 21:20:23 +08001434 struct ahash_request *md5_req;
Eric Dumazet19689e32016-06-27 18:51:53 +02001435 void *scratch;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001436};
1437
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001438/* - functions */
Eric Dumazet39f8e582015-03-24 15:58:55 -07001439int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1440 const struct sock *sk, const struct sk_buff *skb);
Joe Perches5c9f3022013-09-23 11:33:32 -07001441int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1442 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp);
1443int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
1444 int family);
Eric Dumazetb83e3de2015-09-25 07:39:15 -07001445struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
Eric Dumazetfd3a1542015-03-24 15:58:56 -07001446 const struct sock *addr_sk);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001447
YOSHIFUJI Hideaki9501f972008-04-18 12:45:16 +09001448#ifdef CONFIG_TCP_MD5SIG
Eric Dumazetb83e3de2015-09-25 07:39:15 -07001449struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
Joe Perches5c9f3022013-09-23 11:33:32 -07001450 const union tcp_md5_addr *addr,
1451 int family);
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001452#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key)
YOSHIFUJI Hideaki9501f972008-04-18 12:45:16 +09001453#else
Eric Dumazetb83e3de2015-09-25 07:39:15 -07001454static inline struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
Eric Dumazeta915da9b2012-01-31 05:18:33 +00001455 const union tcp_md5_addr *addr,
1456 int family)
1457{
1458 return NULL;
1459}
YOSHIFUJI Hideaki9501f972008-04-18 12:45:16 +09001460#define tcp_twsk_md5_key(twsk) NULL
1461#endif
1462
Joe Perches5c9f3022013-09-23 11:33:32 -07001463bool tcp_alloc_md5sig_pool(void);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001464
Joe Perches5c9f3022013-09-23 11:33:32 -07001465struct tcp_md5sig_pool *tcp_get_md5sig_pool(void);
Eric Dumazet71cea172013-05-20 06:52:26 +00001466static inline void tcp_put_md5sig_pool(void)
1467{
1468 local_bh_enable();
1469}
Eric Dumazet35790c02010-05-16 00:34:04 -07001470
Joe Perches5c9f3022013-09-23 11:33:32 -07001471int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *,
1472 unsigned int header_len);
1473int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1474 const struct tcp_md5sig_key *key);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001475
Jerry Chu10467162012-08-31 12:29:11 +00001476/* From tcp_fastopen.c */
Joe Perches5c9f3022013-09-23 11:33:32 -07001477void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
1478 struct tcp_fastopen_cookie *cookie, int *syn_loss,
1479 unsigned long *last_syn_loss);
1480void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
Daniel Lee2646c832015-04-06 14:37:27 -07001481 struct tcp_fastopen_cookie *cookie, bool syn_lost,
1482 u16 try_exp);
Yuchung Cheng783237e2012-07-19 06:43:07 +00001483struct tcp_fastopen_request {
1484 /* Fast Open cookie. Size 0 means a cookie request */
1485 struct tcp_fastopen_cookie cookie;
1486 struct msghdr *data; /* data in MSG_FASTOPEN */
Eric Dumazetf5ddcbb2014-02-20 10:09:18 -08001487 size_t size;
1488 int copied; /* queued in tcp_connect() */
Yuchung Cheng783237e2012-07-19 06:43:07 +00001489};
Yuchung Cheng783237e2012-07-19 06:43:07 +00001490void tcp_free_fastopen_req(struct tcp_sock *tp);
1491
Jerry Chu10467162012-08-31 12:29:11 +00001492extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
1493int tcp_fastopen_reset_cipher(void *key, unsigned int len);
Eric Dumazet61d2bca2016-02-01 21:03:07 -08001494void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
Eric Dumazet7c85af82015-09-24 17:16:05 -07001495struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
1496 struct request_sock *req,
1497 struct tcp_fastopen_cookie *foc,
1498 struct dst_entry *dst);
Hannes Frederic Sowa222e83d2013-10-19 21:48:58 +02001499void tcp_fastopen_init_key_once(bool publish);
Wei Wang065263f2017-01-23 10:59:20 -08001500bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
1501 struct tcp_fastopen_cookie *cookie);
Wei Wang19f6d3f2017-01-23 10:59:22 -08001502bool tcp_fastopen_defer_connect(struct sock *sk, int *err);
Jerry Chu10467162012-08-31 12:29:11 +00001503#define TCP_FASTOPEN_KEY_LENGTH 16
1504
1505/* Fastopen key context */
1506struct tcp_fastopen_context {
Eric Dumazet7ae86392013-06-25 01:21:06 -07001507 struct crypto_cipher *tfm;
1508 __u8 key[TCP_FASTOPEN_KEY_LENGTH];
1509 struct rcu_head rcu;
Jerry Chu10467162012-08-31 12:29:11 +00001510};
1511
Wei Wangcf1ef3f2017-04-20 14:45:46 -07001512extern unsigned int sysctl_tcp_fastopen_blackhole_timeout;
Wei Wang46c2fa32017-04-20 14:45:47 -07001513void tcp_fastopen_active_disable(struct sock *sk);
Wei Wangcf1ef3f2017-04-20 14:45:46 -07001514bool tcp_fastopen_active_should_disable(struct sock *sk);
1515void tcp_fastopen_active_disable_ofo_check(struct sock *sk);
1516void tcp_fastopen_active_timeout_reset(void);
1517
Francis Yan05b055e2016-11-27 23:07:13 -08001518/* Latencies incurred by various limits for a sender. They are
1519 * chronograph-like stats that are mutually exclusive.
1520 */
1521enum tcp_chrono {
1522 TCP_CHRONO_UNSPEC,
1523 TCP_CHRONO_BUSY, /* Actively sending data (non-empty write queue) */
1524 TCP_CHRONO_RWND_LIMITED, /* Stalled by insufficient receive window */
1525 TCP_CHRONO_SNDBUF_LIMITED, /* Stalled by insufficient send buffer */
1526 __TCP_CHRONO_MAX,
1527};
1528
1529void tcp_chrono_start(struct sock *sk, const enum tcp_chrono type);
1530void tcp_chrono_stop(struct sock *sk, const enum tcp_chrono type);
1531
David S. Millerfe067e82007-03-07 12:12:44 -08001532/* write queue abstraction */
1533static inline void tcp_write_queue_purge(struct sock *sk)
1534{
1535 struct sk_buff *skb;
1536
Francis Yan0f872302016-11-27 23:07:14 -08001537 tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
David S. Millerfe067e82007-03-07 12:12:44 -08001538 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
Hideo Aoki3ab224b2007-12-31 00:11:19 -08001539 sk_wmem_free_skb(sk, skb);
1540 sk_mem_reclaim(sk);
Ilpo Järvinen8818a9d2009-12-02 22:24:02 -08001541 tcp_clear_all_retrans_hints(tcp_sk(sk));
David S. Millerfe067e82007-03-07 12:12:44 -08001542}
1543
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001544static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk)
David S. Millerfe067e82007-03-07 12:12:44 -08001545{
David S. Millercd07a8e2008-09-23 00:50:13 -07001546 return skb_peek(&sk->sk_write_queue);
David S. Millerfe067e82007-03-07 12:12:44 -08001547}
1548
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001549static inline struct sk_buff *tcp_write_queue_tail(const struct sock *sk)
David S. Millerfe067e82007-03-07 12:12:44 -08001550{
David S. Millercd07a8e2008-09-23 00:50:13 -07001551 return skb_peek_tail(&sk->sk_write_queue);
David S. Millerfe067e82007-03-07 12:12:44 -08001552}
1553
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001554static inline struct sk_buff *tcp_write_queue_next(const struct sock *sk,
1555 const struct sk_buff *skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001556{
David S. Millercd07a8e2008-09-23 00:50:13 -07001557 return skb_queue_next(&sk->sk_write_queue, skb);
David S. Millerfe067e82007-03-07 12:12:44 -08001558}
1559
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001560static inline struct sk_buff *tcp_write_queue_prev(const struct sock *sk,
1561 const struct sk_buff *skb)
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08001562{
1563 return skb_queue_prev(&sk->sk_write_queue, skb);
1564}
1565
David S. Millerfe067e82007-03-07 12:12:44 -08001566#define tcp_for_write_queue(skb, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001567 skb_queue_walk(&(sk)->sk_write_queue, skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001568
1569#define tcp_for_write_queue_from(skb, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001570 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001571
Ilpo Järvinen234b6862007-12-02 00:48:02 +02001572#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001573 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
Ilpo Järvinen234b6862007-12-02 00:48:02 +02001574
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001575static inline struct sk_buff *tcp_send_head(const struct sock *sk)
David S. Millerfe067e82007-03-07 12:12:44 -08001576{
1577 return sk->sk_send_head;
1578}
1579
David S. Millercd07a8e2008-09-23 00:50:13 -07001580static inline bool tcp_skb_is_last(const struct sock *sk,
1581 const struct sk_buff *skb)
1582{
1583 return skb_queue_is_last(&sk->sk_write_queue, skb);
1584}
1585
Eric Dumazetcf533ea2011-10-21 05:22:42 -04001586static inline void tcp_advance_send_head(struct sock *sk, const struct sk_buff *skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001587{
David S. Millercd07a8e2008-09-23 00:50:13 -07001588 if (tcp_skb_is_last(sk, skb))
David S. Millerfe067e82007-03-07 12:12:44 -08001589 sk->sk_send_head = NULL;
David S. Millercd07a8e2008-09-23 00:50:13 -07001590 else
1591 sk->sk_send_head = tcp_write_queue_next(sk, skb);
David S. Millerfe067e82007-03-07 12:12:44 -08001592}
1593
1594static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1595{
Francis Yan0f872302016-11-27 23:07:14 -08001596 if (sk->sk_send_head == skb_unlinked) {
David S. Millerfe067e82007-03-07 12:12:44 -08001597 sk->sk_send_head = NULL;
Francis Yan0f872302016-11-27 23:07:14 -08001598 tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
1599 }
Eric Dumazetbb1fcec2016-08-17 05:56:26 -07001600 if (tcp_sk(sk)->highest_sack == skb_unlinked)
1601 tcp_sk(sk)->highest_sack = NULL;
David S. Millerfe067e82007-03-07 12:12:44 -08001602}
1603
1604static inline void tcp_init_send_head(struct sock *sk)
1605{
1606 sk->sk_send_head = NULL;
1607}
1608
1609static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1610{
1611 __skb_queue_tail(&sk->sk_write_queue, skb);
1612}
1613
1614static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1615{
1616 __tcp_add_write_queue_tail(sk, skb);
1617
1618 /* Queue it, remembering where we must start sending. */
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001619 if (sk->sk_send_head == NULL) {
David S. Millerfe067e82007-03-07 12:12:44 -08001620 sk->sk_send_head = skb;
Francis Yan0f872302016-11-27 23:07:14 -08001621 tcp_chrono_start(sk, TCP_CHRONO_BUSY);
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001622
1623 if (tcp_sk(sk)->highest_sack == NULL)
1624 tcp_sk(sk)->highest_sack = skb;
1625 }
David S. Millerfe067e82007-03-07 12:12:44 -08001626}
1627
1628static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1629{
1630 __skb_queue_head(&sk->sk_write_queue, skb);
1631}
1632
1633/* Insert buff after skb on the write queue of sk. */
1634static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1635 struct sk_buff *buff,
1636 struct sock *sk)
1637{
Gerrit Renker7de6c032008-04-14 00:05:09 -07001638 __skb_queue_after(&sk->sk_write_queue, skb, buff);
David S. Millerfe067e82007-03-07 12:12:44 -08001639}
1640
David S. Miller43f59c82008-09-21 21:28:51 -07001641/* Insert new before skb on the write queue of sk. */
David S. Millerfe067e82007-03-07 12:12:44 -08001642static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1643 struct sk_buff *skb,
1644 struct sock *sk)
1645{
David S. Miller43f59c82008-09-21 21:28:51 -07001646 __skb_queue_before(&sk->sk_write_queue, skb, new);
Ilpo Järvinen6e421412007-11-19 23:24:09 -08001647
1648 if (sk->sk_send_head == skb)
1649 sk->sk_send_head = new;
David S. Millerfe067e82007-03-07 12:12:44 -08001650}
1651
1652static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1653{
1654 __skb_unlink(skb, &sk->sk_write_queue);
1655}
1656
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001657static inline bool tcp_write_queue_empty(struct sock *sk)
David S. Millerfe067e82007-03-07 12:12:44 -08001658{
1659 return skb_queue_empty(&sk->sk_write_queue);
1660}
1661
Krishna Kumar12d50c42009-12-08 22:26:13 +00001662static inline void tcp_push_pending_frames(struct sock *sk)
1663{
1664 if (tcp_send_head(sk)) {
1665 struct tcp_sock *tp = tcp_sk(sk);
1666
1667 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
1668 }
1669}
1670
Neal Cardwellecb97192012-02-27 17:52:52 -05001671/* Start sequence of the skb just after the highest skb with SACKed
1672 * bit, valid only if sacked_out > 0 or when the caller has ensured
1673 * validity by itself.
Ilpo Järvinena47e5a92007-11-15 19:41:46 -08001674 */
1675static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1676{
1677 if (!tp->sacked_out)
1678 return tp->snd_una;
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001679
1680 if (tp->highest_sack == NULL)
1681 return tp->snd_nxt;
1682
Ilpo Järvinena47e5a92007-11-15 19:41:46 -08001683 return TCP_SKB_CB(tp->highest_sack)->seq;
1684}
1685
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001686static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1687{
1688 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1689 tcp_write_queue_next(sk, skb);
1690}
1691
1692static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1693{
1694 return tcp_sk(sk)->highest_sack;
1695}
1696
1697static inline void tcp_highest_sack_reset(struct sock *sk)
1698{
1699 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1700}
1701
1702/* Called when old skb is about to be deleted (to be combined with new skb) */
1703static inline void tcp_highest_sack_combine(struct sock *sk,
1704 struct sk_buff *old,
1705 struct sk_buff *new)
1706{
1707 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1708 tcp_sk(sk)->highest_sack = new;
1709}
1710
Florian Westphalb1f0a0e2015-12-21 21:29:24 +01001711/* This helper checks if socket has IP_TRANSPARENT set */
1712static inline bool inet_sk_transparent(const struct sock *sk)
1713{
1714 switch (sk->sk_state) {
1715 case TCP_TIME_WAIT:
1716 return inet_twsk(sk)->tw_transparent;
1717 case TCP_NEW_SYN_RECV:
1718 return inet_rsk(inet_reqsk(sk))->no_srccheck;
1719 }
1720 return inet_sk(sk)->transparent;
1721}
1722
Andreas Petlund5aa4b322010-02-18 02:45:45 +00001723/* Determines whether this is a thin stream (which may suffer from
1724 * increased latency). Used to trigger latency-reducing mechanisms.
1725 */
Eric Dumazeta2a385d2012-05-16 23:15:34 +00001726static inline bool tcp_stream_is_thin(struct tcp_sock *tp)
Andreas Petlund5aa4b322010-02-18 02:45:45 +00001727{
1728 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp);
1729}
1730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731/* /proc */
1732enum tcp_seq_states {
1733 TCP_SEQ_STATE_LISTENING,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 TCP_SEQ_STATE_ESTABLISHED,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735};
1736
Arjan van de Ven73cb88e2011-10-30 06:46:30 +00001737int tcp_seq_open(struct inode *inode, struct file *file);
1738
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739struct tcp_seq_afinfo {
Arjan van de Ven73cb88e2011-10-30 06:46:30 +00001740 char *name;
1741 sa_family_t family;
1742 const struct file_operations *seq_fops;
1743 struct seq_operations seq_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744};
1745
1746struct tcp_iter_state {
Denis V. Luneva4146b12008-04-13 22:11:14 -07001747 struct seq_net_private p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 sa_family_t family;
1749 enum tcp_seq_states state;
1750 struct sock *syn_wait_sk;
Eric W. Biedermana7cb5a42012-05-24 01:10:10 -06001751 int bucket, offset, sbucket, num;
Tom Herberta8b690f2010-06-07 00:43:42 -07001752 loff_t last_pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753};
1754
Joe Perches5c9f3022013-09-23 11:33:32 -07001755int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1756void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001758extern struct request_sock_ops tcp_request_sock_ops;
Glenn Griffinc6aefaf2008-02-07 21:49:26 -08001759extern struct request_sock_ops tcp6_request_sock_ops;
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001760
Joe Perches5c9f3022013-09-23 11:33:32 -07001761void tcp_v4_destroy_sock(struct sock *sk);
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001762
Eric Dumazet28be6e02013-10-18 10:36:17 -07001763struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
Joe Perches5c9f3022013-09-23 11:33:32 -07001764 netdev_features_t features);
1765struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb);
1766int tcp_gro_complete(struct sk_buff *skb);
Daniel Borkmann28850dc2013-06-07 05:11:46 +00001767
Joe Perches5c9f3022013-09-23 11:33:32 -07001768void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
Herbert Xuf4c50d92006-06-22 03:02:40 -07001769
Eric Dumazetc9bee3b72013-07-22 20:27:07 -07001770static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
1771{
Nikolay Borisov4979f2d2016-02-03 09:46:57 +02001772 struct net *net = sock_net((struct sock *)tp);
1773 return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat;
Eric Dumazetc9bee3b72013-07-22 20:27:07 -07001774}
1775
1776static inline bool tcp_stream_memory_free(const struct sock *sk)
1777{
1778 const struct tcp_sock *tp = tcp_sk(sk);
1779 u32 notsent_bytes = tp->write_seq - tp->snd_nxt;
1780
1781 return notsent_bytes < tcp_notsent_lowat(tp);
1782}
1783
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001784#ifdef CONFIG_PROC_FS
Joe Perches5c9f3022013-09-23 11:33:32 -07001785int tcp4_proc_init(void);
1786void tcp4_proc_exit(void);
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001787#endif
1788
Eric Dumazetea3bea32015-09-25 07:39:23 -07001789int tcp_rtx_synack(const struct sock *sk, struct request_sock *req);
Octavian Purdila1fb6f152014-06-25 17:10:02 +03001790int tcp_conn_request(struct request_sock_ops *rsk_ops,
1791 const struct tcp_request_sock_ops *af_ops,
1792 struct sock *sk, struct sk_buff *skb);
Octavian Purdila5db92c92014-06-25 17:09:59 +03001793
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001794/* TCP af-specific functions */
1795struct tcp_sock_af_ops {
1796#ifdef CONFIG_TCP_MD5SIG
Eric Dumazetb83e3de2015-09-25 07:39:15 -07001797 struct tcp_md5sig_key *(*md5_lookup) (const struct sock *sk,
Eric Dumazetfd3a1542015-03-24 15:58:56 -07001798 const struct sock *addr_sk);
Eric Dumazet39f8e582015-03-24 15:58:55 -07001799 int (*calc_md5_hash)(char *location,
1800 const struct tcp_md5sig_key *md5,
1801 const struct sock *sk,
1802 const struct sk_buff *skb);
1803 int (*md5_parse)(struct sock *sk,
1804 char __user *optval,
1805 int optlen);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001806#endif
1807};
1808
1809struct tcp_request_sock_ops {
Octavian Purdila2aec4a22014-06-25 17:10:00 +03001810 u16 mss_clamp;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001811#ifdef CONFIG_TCP_MD5SIG
Eric Dumazetb83e3de2015-09-25 07:39:15 -07001812 struct tcp_md5sig_key *(*req_md5_lookup)(const struct sock *sk,
Eric Dumazetfd3a1542015-03-24 15:58:56 -07001813 const struct sock *addr_sk);
Eric Dumazet39f8e582015-03-24 15:58:55 -07001814 int (*calc_md5_hash) (char *location,
1815 const struct tcp_md5sig_key *md5,
1816 const struct sock *sk,
1817 const struct sk_buff *skb);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001818#endif
Eric Dumazetb40cf182015-09-25 07:39:08 -07001819 void (*init_req)(struct request_sock *req,
1820 const struct sock *sk_listener,
Octavian Purdila16bea702014-06-25 17:09:53 +03001821 struct sk_buff *skb);
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001822#ifdef CONFIG_SYN_COOKIES
Eric Dumazet3f684b42015-09-29 07:42:49 -07001823 __u32 (*cookie_init_seq)(const struct sk_buff *skb,
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001824 __u16 *mss);
1825#endif
Eric Dumazetf9646292015-09-29 07:42:50 -07001826 struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl,
Soheil Hassas Yeganeh4396e462017-03-15 16:30:46 -04001827 const struct request_sock *req);
Eric Dumazet84b114b2017-05-05 06:56:54 -07001828 u32 (*init_seq)(const struct sk_buff *skb);
1829 u32 (*init_ts_off)(const struct sk_buff *skb);
Eric Dumazet0f935db2015-09-25 07:39:21 -07001830 int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
Octavian Purdilad6274bd2014-06-25 17:09:58 +03001831 struct flowi *fl, struct request_sock *req,
Eric Dumazetdc6ef6b2015-10-16 13:00:01 -07001832 struct tcp_fastopen_cookie *foc,
Eric Dumazetb3d05142016-04-13 22:05:39 -07001833 enum tcp_synack_type synack_type);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001834};
1835
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001836#ifdef CONFIG_SYN_COOKIES
1837static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
Eric Dumazet3f684b42015-09-29 07:42:49 -07001838 const struct sock *sk, struct sk_buff *skb,
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001839 __u16 *mss)
1840{
Eric Dumazet3f684b42015-09-29 07:42:49 -07001841 tcp_synq_overflow(sk);
Eric Dumazet02a1d6e2016-04-27 16:44:39 -07001842 __NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);
Eric Dumazet3f684b42015-09-29 07:42:49 -07001843 return ops->cookie_init_seq(skb, mss);
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001844}
1845#else
1846static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
Eric Dumazet3f684b42015-09-29 07:42:49 -07001847 const struct sock *sk, struct sk_buff *skb,
Octavian Purdilafb7b37a2014-06-25 17:09:54 +03001848 __u16 *mss)
1849{
1850 return 0;
1851}
1852#endif
1853
Joe Perches5c9f3022013-09-23 11:33:32 -07001854int tcpv4_offload_init(void);
Daniel Borkmann28850dc2013-06-07 05:11:46 +00001855
Joe Perches5c9f3022013-09-23 11:33:32 -07001856void tcp_v4_init(void);
1857void tcp_init(void);
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001858
Yuchung Cheng659a8ad2015-10-16 21:57:46 -07001859/* tcp_recovery.c */
Eric Dumazet128eda82017-04-25 10:15:34 -07001860extern void tcp_rack_mark_lost(struct sock *sk);
Yuchung Cheng1d0833d2017-01-12 22:11:34 -08001861extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
Eric Dumazetd2329f12017-04-25 10:15:38 -07001862 const struct skb_mstamp *xmit_time);
Yuchung Cheng57dde7f2017-01-12 22:11:33 -08001863extern void tcp_rack_reo_timeout(struct sock *sk);
Yuchung Cheng659a8ad2015-10-16 21:57:46 -07001864
Cong Wange25f8662014-10-15 14:33:21 -07001865/*
1866 * Save and compile IPv4 options, return a pointer to it
1867 */
1868static inline struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
1869{
1870 const struct ip_options *opt = &TCP_SKB_CB(skb)->header.h4.opt;
1871 struct ip_options_rcu *dopt = NULL;
1872
Cong Wang461b74c2014-10-15 14:33:22 -07001873 if (opt->optlen) {
Cong Wange25f8662014-10-15 14:33:21 -07001874 int opt_size = sizeof(*dopt) + opt->optlen;
1875
1876 dopt = kmalloc(opt_size, GFP_ATOMIC);
1877 if (dopt && __ip_options_echo(&dopt->opt, skb, opt)) {
1878 kfree(dopt);
1879 dopt = NULL;
1880 }
1881 }
1882 return dopt;
1883}
1884
Eric Dumazet98781962015-02-03 18:31:53 -08001885/* locally generated TCP pure ACKs have skb->truesize == 2
1886 * (check tcp_send_ack() in net/ipv4/tcp_output.c )
1887 * This is much faster than dissecting the packet to find out.
1888 * (Think of GRE encapsulations, IPv4, IPv6, ...)
1889 */
1890static inline bool skb_is_tcp_pure_ack(const struct sk_buff *skb)
1891{
1892 return skb->truesize == 2;
1893}
1894
1895static inline void skb_set_tcp_pure_ack(struct sk_buff *skb)
1896{
1897 skb->truesize = 2;
1898}
1899
Tom Herbert473bd232016-03-07 14:11:05 -08001900static inline int tcp_inq(struct sock *sk)
1901{
1902 struct tcp_sock *tp = tcp_sk(sk);
1903 int answ;
1904
1905 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
1906 answ = 0;
1907 } else if (sock_flag(sk, SOCK_URGINLINE) ||
1908 !tp->urg_data ||
1909 before(tp->urg_seq, tp->copied_seq) ||
1910 !before(tp->urg_seq, tp->rcv_nxt)) {
1911
1912 answ = tp->rcv_nxt - tp->copied_seq;
1913
1914 /* Subtract 1, if FIN was received */
1915 if (answ && sock_flag(sk, SOCK_DONE))
1916 answ--;
1917 } else {
1918 answ = tp->urg_seq - tp->copied_seq;
1919 }
1920
1921 return answ;
1922}
1923
Tom Herbert32035582016-08-28 14:43:18 -07001924int tcp_peek_len(struct socket *sock);
1925
Martin KaFai Laua44d6ea2016-03-14 10:52:15 -07001926static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
1927{
1928 u16 segs_in;
1929
1930 segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1931 tp->segs_in += segs_in;
1932 if (skb->len > tcp_hdrlen(skb))
1933 tp->data_segs_in += segs_in;
1934}
1935
Eric Dumazet9caad862016-04-01 08:52:20 -07001936/*
1937 * TCP listen path runs lockless.
1938 * We forced "struct sock" to be const qualified to make sure
1939 * we don't modify one of its field by mistake.
1940 * Here, we increment sk_drops which is an atomic_t, so we can safely
1941 * make sock writable again.
1942 */
1943static inline void tcp_listendrop(const struct sock *sk)
1944{
1945 atomic_inc(&((struct sock *)sk)->sk_drops);
Eric Dumazet02a1d6e2016-04-27 16:44:39 -07001946 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
Eric Dumazet9caad862016-04-01 08:52:20 -07001947}
1948
Eric Dumazet218af592017-05-16 04:24:36 -07001949enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer);
1950
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951#endif /* _TCP_H */