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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
21#define TCP_DEBUG 1
22#define FASTRETRANS_DEBUG 1
23
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/list.h>
25#include <linux/tcp.h>
26#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>
Chris Leech97fc2f02006-05-23 17:55:33 -070030#include <linux/dmaengine.h>
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -080031#include <linux/crypto.h>
Glenn Griffinc6aefaf2008-02-07 21:49:26 -080032#include <linux/cryptohash.h>
William Allen Simpson435cf552009-12-02 18:17:05 +000033#include <linux/kref.h>
Arnaldo Carvalho de Melo3f421ba2005-08-09 20:11:08 -070034
35#include <net/inet_connection_sock.h>
Arnaldo Carvalho de Melo295ff7e2005-08-09 20:44:40 -070036#include <net/inet_timewait_sock.h>
Arnaldo Carvalho de Melo77d8bf92005-08-09 20:00:51 -070037#include <net/inet_hashtables.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038#include <net/checksum.h>
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070039#include <net/request_sock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <net/sock.h>
41#include <net/snmp.h>
42#include <net/ip.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070043#include <net/tcp_states.h>
Ilpo Järvinenbdf1ee52007-05-27 02:04:16 -070044#include <net/inet_ecn.h>
Satoru SATOH0c266892009-05-04 11:11:01 -070045#include <net/dst.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/seq_file.h>
48
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052extern void 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
57/*
58 * Never offer a window over 32767 without using window scaling. Some
59 * poor stacks do signed 16bit maths!
60 */
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 */
67#define TCP_BASE_MSS 512
68
Linus Torvalds1da177e2005-04-16 15:20:36 -070069/* After receiving this amount of duplicate ACKs fast retransmit starts. */
70#define TCP_FASTRETRANS_THRESH 3
71
72/* Maximal reordering. */
73#define TCP_MAX_REORDERING 127
74
75/* Maximal number of ACKs sent quickly to accelerate slow-start. */
76#define TCP_MAX_QUICKACKS 16U
77
78/* urg_data states */
79#define TCP_URG_VALID 0x0100
80#define TCP_URG_NOTYET 0x0200
81#define TCP_URG_READ 0x0400
82
83#define TCP_RETR1 3 /*
84 * This is how many retries it does before it
85 * tries to figure out if the gateway is
86 * down. Minimal RFC value is 3; it corresponds
87 * to ~3sec-8min depending on RTO.
88 */
89
90#define TCP_RETR2 15 /*
91 * This should take at least
92 * 90 minutes to time out.
93 * RFC1122 says that the limit is 100 sec.
94 * 15 is ~13-30min depending on RTO.
95 */
96
97#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -080098 * connection: ~180sec is RFC minimum */
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -0800101 * connection: ~180sec is RFC minimum */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
103
104#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
105 * socket. 7 is ~50sec-16min.
106 */
107
108
109#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
110 * state, about 60 seconds */
111#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
112 /* BSD style FIN_WAIT2 deadlock breaker.
113 * It used to be 3min, new value is 60sec,
114 * to combine FIN-WAIT-2 timeout with
115 * TIME-WAIT timer.
116 */
117
118#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119#if HZ >= 100
120#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
121#define TCP_ATO_MIN ((unsigned)(HZ/25))
122#else
123#define TCP_DELACK_MIN 4U
124#define TCP_ATO_MIN 4U
125#endif
126#define TCP_RTO_MAX ((unsigned)(120*HZ))
127#define TCP_RTO_MIN ((unsigned)(HZ/5))
128#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129
130#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
131 * for local resources.
132 */
133
134#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
135#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
136#define TCP_KEEPALIVE_INTVL (75*HZ)
137
138#define MAX_TCP_KEEPIDLE 32767
139#define MAX_TCP_KEEPINTVL 32767
140#define MAX_TCP_KEEPCNT 127
141#define MAX_TCP_SYNCNT 127
142
143#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
146#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
147 * after this time. It should be equal
148 * (or greater than) TCP_TIMEWAIT_LEN
149 * to provide reliability equal to one
150 * provided by timewait state.
151 */
152#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
153 * timestamps. It must be less than
154 * minimal timewait lifetime.
155 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156/*
157 * TCP option
158 */
159
160#define TCPOPT_NOP 1 /* Padding */
161#define TCPOPT_EOL 0 /* End of options */
162#define TCPOPT_MSS 2 /* Segment size negotiating */
163#define TCPOPT_WINDOW 3 /* Window scaling */
164#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
165#define TCPOPT_SACK 5 /* SACK Block */
166#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800167#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
William Allen Simpson435cf552009-12-02 18:17:05 +0000168#define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
170/*
171 * TCP option lengths
172 */
173
174#define TCPOLEN_MSS 4
175#define TCPOLEN_WINDOW 3
176#define TCPOLEN_SACK_PERM 2
177#define TCPOLEN_TIMESTAMP 10
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800178#define TCPOLEN_MD5SIG 18
William Allen Simpson435cf552009-12-02 18:17:05 +0000179#define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */
180#define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */
181#define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN)
182#define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
184/* But this is what stacks really send out. */
185#define TCPOLEN_TSTAMP_ALIGNED 12
186#define TCPOLEN_WSCALE_ALIGNED 4
187#define TCPOLEN_SACKPERM_ALIGNED 4
188#define TCPOLEN_SACK_BASE 2
189#define TCPOLEN_SACK_BASE_ALIGNED 4
190#define TCPOLEN_SACK_PERBLOCK 8
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800191#define TCPOLEN_MD5SIG_ALIGNED 20
Adam Langley33ad7982008-07-19 00:04:31 -0700192#define TCPOLEN_MSS_ALIGNED 4
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194/* Flags in tp->nonagle */
195#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
196#define TCP_NAGLE_CORK 2 /* Socket is corked */
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -0800197#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
Andreas Petlund36e31b0a2010-02-18 02:47:01 +0000199/* TCP thin-stream limits */
200#define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */
201
Arnaldo Carvalho de Melo295ff7e2005-08-09 20:44:40 -0700202extern struct inet_timewait_death_row tcp_death_row;
203
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204/* sysctl variables for tcp */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205extern int sysctl_tcp_timestamps;
206extern int sysctl_tcp_window_scaling;
207extern int sysctl_tcp_sack;
208extern int sysctl_tcp_fin_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209extern int sysctl_tcp_keepalive_time;
210extern int sysctl_tcp_keepalive_probes;
211extern int sysctl_tcp_keepalive_intvl;
212extern int sysctl_tcp_syn_retries;
213extern int sysctl_tcp_synack_retries;
214extern int sysctl_tcp_retries1;
215extern int sysctl_tcp_retries2;
216extern int sysctl_tcp_orphan_retries;
217extern int sysctl_tcp_syncookies;
218extern int sysctl_tcp_retrans_collapse;
219extern int sysctl_tcp_stdurg;
220extern int sysctl_tcp_rfc1337;
221extern int sysctl_tcp_abort_on_overflow;
222extern int sysctl_tcp_max_orphans;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223extern int sysctl_tcp_fack;
224extern int sysctl_tcp_reordering;
225extern int sysctl_tcp_ecn;
226extern int sysctl_tcp_dsack;
227extern int sysctl_tcp_mem[3];
228extern int sysctl_tcp_wmem[3];
229extern int sysctl_tcp_rmem[3];
230extern int sysctl_tcp_app_win;
231extern int sysctl_tcp_adv_win_scale;
232extern int sysctl_tcp_tw_reuse;
233extern int sysctl_tcp_frto;
Ilpo Järvinen3cfe3ba2007-02-27 10:09:49 -0800234extern int sysctl_tcp_frto_response;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235extern int sysctl_tcp_low_latency;
Chris Leech95937822006-05-23 18:02:55 -0700236extern int sysctl_tcp_dma_copybreak;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237extern int sysctl_tcp_nometrics_save;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238extern int sysctl_tcp_moderate_rcvbuf;
239extern int sysctl_tcp_tso_win_divisor;
Stephen Hemminger9772efb2005-11-10 17:09:53 -0800240extern int sysctl_tcp_abc;
John Heffner5d424d52006-03-20 17:53:41 -0800241extern int sysctl_tcp_mtu_probing;
242extern int sysctl_tcp_base_mss;
Rick Jones15d99e02006-03-20 22:40:29 -0800243extern int sysctl_tcp_workaround_signed_windows;
David S. Miller35089bb2006-06-13 22:33:04 -0700244extern int sysctl_tcp_slow_start_after_idle;
John Heffner886236c2007-03-25 19:21:45 -0700245extern int sysctl_tcp_max_ssthresh;
William Allen Simpson519855c2009-12-02 18:14:19 +0000246extern int sysctl_tcp_cookie_size;
Andreas Petlund36e31b0a2010-02-18 02:47:01 +0000247extern int sysctl_tcp_thin_linear_timeouts;
Andreas Petlund7e380172010-02-18 04:48:19 +0000248extern int sysctl_tcp_thin_dupack;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250extern atomic_t tcp_memory_allocated;
Eric Dumazet17483762008-11-25 21:16:35 -0800251extern struct percpu_counter tcp_sockets_allocated;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252extern int tcp_memory_pressure;
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 * The next routines deal with comparing 32 bit unsigned ints
256 * and worry about wraparound (automatic with unsigned arithmetic).
257 */
258
259static inline int before(__u32 seq1, __u32 seq2)
260{
Gerrit Renker0d630cc2007-01-04 12:25:16 -0800261 return (__s32)(seq1-seq2) < 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262}
Gerrit Renker9a036b9c2006-12-20 10:25:55 -0800263#define after(seq2, seq1) before(seq1, seq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265/* is s2<=s1<=s3 ? */
266static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
267{
268 return seq3 - seq2 >= seq1 - seq2;
269}
270
Pavel Emelianove4fd5da2007-05-29 13:19:18 -0700271static inline int tcp_too_many_orphans(struct sock *sk, int num)
272{
273 return (num > sysctl_tcp_max_orphans) ||
274 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
275 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
276}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
Florian Westphala0f82f62009-04-19 09:43:48 +0000278/* syncookies: remember time of last synqueue overflow */
279static inline void tcp_synq_overflow(struct sock *sk)
280{
281 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
282}
283
284/* syncookies: no recent synqueue overflow on this listening socket? */
285static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
286{
287 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
288 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
289}
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291extern struct proto tcp_prot;
292
Pavel Emelyanov57ef42d2008-07-18 04:02:08 -0700293#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
294#define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
295#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
296#define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298extern void tcp_v4_err(struct sk_buff *skb, u32);
299
300extern void tcp_shutdown (struct sock *sk, int how);
301
302extern int tcp_v4_rcv(struct sk_buff *skb);
303
304extern int tcp_v4_remember_stamp(struct sock *sk);
305
Arnaldo Carvalho de Melo8feaf0c02005-08-09 20:09:30 -0700306extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
David S. Miller3516ffb2007-08-02 19:23:56 -0700308extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 struct msghdr *msg, size_t size);
310extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
311
312extern int tcp_ioctl(struct sock *sk,
313 int cmd,
314 unsigned long arg);
315
316extern int tcp_rcv_state_process(struct sock *sk,
317 struct sk_buff *skb,
318 struct tcphdr *th,
319 unsigned len);
320
321extern int tcp_rcv_established(struct sock *sk,
322 struct sk_buff *skb,
323 struct tcphdr *th,
324 unsigned len);
325
326extern void tcp_rcv_space_adjust(struct sock *sk);
327
Chris Leech0e4b4992006-05-23 18:00:16 -0700328extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
329
Arnaldo Carvalho de Melo6d6ee432005-12-13 23:25:19 -0800330extern int tcp_twsk_unique(struct sock *sk,
331 struct sock *sktw, void *twp);
332
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -0800333extern void tcp_twsk_destructor(struct sock *sk);
334
Jens Axboe9c55e012007-11-06 23:30:13 -0800335extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
336 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
337
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700338static inline void tcp_dec_quickack_mode(struct sock *sk,
339 const unsigned int pkts)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700341 struct inet_connection_sock *icsk = inet_csk(sk);
David S. Millerfc6415bc2005-07-05 15:17:45 -0700342
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700343 if (icsk->icsk_ack.quick) {
344 if (pkts >= icsk->icsk_ack.quick) {
345 icsk->icsk_ack.quick = 0;
David S. Millerfc6415bc2005-07-05 15:17:45 -0700346 /* Leaving quickack mode we deflate ATO. */
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700347 icsk->icsk_ack.ato = TCP_ATO_MIN;
David S. Millerfc6415bc2005-07-05 15:17:45 -0700348 } else
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700349 icsk->icsk_ack.quick -= pkts;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 }
351}
352
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700353extern void tcp_enter_quickack_mode(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354
Ilpo Järvinenbdf1ee52007-05-27 02:04:16 -0700355#define TCP_ECN_OK 1
356#define TCP_ECN_QUEUE_CWR 2
357#define TCP_ECN_DEMAND_CWR 4
358
359static __inline__ void
360TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
361{
362 if (sysctl_tcp_ecn && th->ece && th->cwr)
363 inet_rsk(req)->ecn_ok = 1;
364}
365
Eric Dumazetfd2c3ef2009-11-03 03:26:03 +0000366enum tcp_tw_status {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 TCP_TW_SUCCESS = 0,
368 TCP_TW_RST = 1,
369 TCP_TW_ACK = 2,
370 TCP_TW_SYN = 3
371};
372
373
Arnaldo Carvalho de Melo8feaf0c02005-08-09 20:09:30 -0700374extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 struct sk_buff *skb,
Arnaldo Carvalho de Melo8feaf0c02005-08-09 20:09:30 -0700376 const struct tcphdr *th);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
378extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -0700379 struct request_sock *req,
380 struct request_sock **prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381extern int tcp_child_process(struct sock *parent,
382 struct sock *child,
383 struct sk_buff *skb);
Ilpo Järvinen46d0de42007-02-21 23:10:39 -0800384extern int tcp_use_frto(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385extern void tcp_enter_frto(struct sock *sk);
386extern void tcp_enter_loss(struct sock *sk, int how);
387extern void tcp_clear_retrans(struct tcp_sock *tp);
388extern void tcp_update_metrics(struct sock *sk);
389
390extern void tcp_close(struct sock *sk,
391 long timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
393
394extern int tcp_getsockopt(struct sock *sk, int level,
395 int optname,
396 char __user *optval,
397 int __user *optlen);
398extern int tcp_setsockopt(struct sock *sk, int level,
399 int optname, char __user *optval,
David S. Millerb7058842009-09-30 16:12:20 -0700400 unsigned int optlen);
Dmitry Mishin3fdadf72006-03-20 22:45:21 -0800401extern int compat_tcp_getsockopt(struct sock *sk,
402 int level, int optname,
403 char __user *optval, int __user *optlen);
404extern int compat_tcp_setsockopt(struct sock *sk,
405 int level, int optname,
David S. Millerb7058842009-09-30 16:12:20 -0700406 char __user *optval, unsigned int optlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407extern void tcp_set_keepalive(struct sock *sk, int val);
Octavian Purdila72659ec2010-01-17 19:09:39 -0800408extern void tcp_syn_ack_timeout(struct sock *sk,
409 struct request_sock *req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
411 struct msghdr *msg,
412 size_t len, int nonblock,
413 int flags, int *addr_len);
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415extern void tcp_parse_options(struct sk_buff *skb,
416 struct tcp_options_received *opt_rx,
William Allen Simpson4957faade2009-12-02 18:25:27 +0000417 u8 **hvpp,
David S. Millerbb5b7c12009-12-15 20:56:42 -0800418 int estab);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419
YOSHIFUJI Hideaki7d5d5522008-04-17 12:29:53 +0900420extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
421
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422/*
423 * TCP v4 functions exported for the inet6 API
424 */
425
Arnaldo Carvalho de Melo8292a172005-12-13 23:15:52 -0800426extern void tcp_v4_send_check(struct sock *sk, int len,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 struct sk_buff *skb);
428
429extern int tcp_v4_conn_request(struct sock *sk,
430 struct sk_buff *skb);
431
432extern struct sock * tcp_create_openreq_child(struct sock *sk,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -0700433 struct request_sock *req,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 struct sk_buff *skb);
435
436extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
437 struct sk_buff *skb,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -0700438 struct request_sock *req,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 struct dst_entry *dst);
440
441extern int tcp_v4_do_rcv(struct sock *sk,
442 struct sk_buff *skb);
443
444extern int tcp_v4_connect(struct sock *sk,
445 struct sockaddr *uaddr,
446 int addr_len);
447
448extern int tcp_connect(struct sock *sk);
449
450extern struct sk_buff * tcp_make_synack(struct sock *sk,
451 struct dst_entry *dst,
William Allen Simpsone6b4d112009-12-02 18:07:39 +0000452 struct request_sock *req,
453 struct request_values *rvp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455extern int tcp_disconnect(struct sock *sk, int flags);
456
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458/* From syncookies.c */
Florian Westphal2051f112008-03-23 22:21:28 -0700459extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
461 struct ip_options *opt);
462extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
463 __u16 *mss);
464
Florian Westphal4dfc2812008-04-10 03:12:40 -0700465extern __u32 cookie_init_timestamp(struct request_sock *req);
466extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
467
Glenn Griffinc6aefaf2008-02-07 21:49:26 -0800468/* From net/ipv6/syncookies.c */
469extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
470extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
471 __u16 *mss);
472
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473/* tcp_output.c */
474
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700475extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
476 int nonagle);
477extern int tcp_may_send_now(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
Damian Lukowskif1ecd5d2009-08-26 00:16:31 +0000479extern void tcp_retransmit_timer(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480extern void tcp_xmit_retransmit_queue(struct sock *);
481extern void tcp_simple_retransmit(struct sock *);
482extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
David S. Miller6475be12005-09-01 22:47:01 -0700483extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485extern void tcp_send_probe0(struct sock *);
486extern void tcp_send_partial(struct sock *);
487extern int tcp_write_wakeup(struct sock *);
488extern void tcp_send_fin(struct sock *sk);
Al Virodd0fc662005-10-07 07:46:04 +0100489extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490extern int tcp_send_synack(struct sock *);
David S. Millerc1b4a7e2005-07-05 15:24:38 -0700491extern void tcp_push_one(struct sock *, unsigned int mss_now);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492extern void tcp_send_ack(struct sock *sk);
493extern void tcp_send_delayed_ack(struct sock *sk);
494
David S. Millera762a982005-07-05 15:18:51 -0700495/* tcp_input.c */
496extern void tcp_cwnd_application_limited(struct sock *sk);
497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498/* tcp_timer.c */
499extern void tcp_init_xmit_timers(struct sock *);
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700500static inline void tcp_clear_xmit_timers(struct sock *sk)
501{
502 inet_csk_clear_xmit_timers(sk);
503}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
Ilpo Järvinen0c54b852009-03-14 14:23:05 +0000506extern unsigned int tcp_current_mss(struct sock *sk);
507
508/* Bound MSS / TSO packet size with the half of the window */
509static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
510{
511 if (tp->max_window && pktsize > (tp->max_window >> 1))
512 return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
513 else
514 return pktsize;
515}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516
Arnaldo Carvalho de Melo17b085e2005-08-12 12:59:17 -0300517/* tcp.c */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518extern void tcp_get_info(struct sock *, struct tcp_info *);
519
520/* Read 'sendfile()'-style from a TCP socket */
521typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
522 unsigned int, size_t);
523extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
524 sk_read_actor_t recv_actor);
525
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800526extern void tcp_initialize_rcv_mss(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
John Heffner5d424d52006-03-20 17:53:41 -0800528extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
529extern int tcp_mss_to_mtu(struct sock *sk, int mss);
530extern void tcp_mtup_init(struct sock *sk);
531
Damian Lukowskif1ecd5d2009-08-26 00:16:31 +0000532static inline void tcp_bound_rto(const struct sock *sk)
533{
534 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
535 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
536}
537
538static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
539{
540 return (tp->srtt >> 3) + tp->rttvar;
541}
542
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800543static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544{
545 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
546 ntohl(TCP_FLAG_ACK) |
547 snd_wnd);
548}
549
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800550static inline void tcp_fast_path_on(struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
552 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
553}
554
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700555static inline void tcp_fast_path_check(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556{
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700557 struct tcp_sock *tp = tcp_sk(sk);
558
David S. Millerb03efcf2005-07-08 14:57:23 -0700559 if (skb_queue_empty(&tp->out_of_order_queue) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 tp->rcv_wnd &&
561 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
562 !tp->urg_data)
563 tcp_fast_path_on(tp);
564}
565
Satoru SATOH0c266892009-05-04 11:11:01 -0700566/* Compute the actual rto_min value */
567static inline u32 tcp_rto_min(struct sock *sk)
568{
569 struct dst_entry *dst = __sk_dst_get(sk);
570 u32 rto_min = TCP_RTO_MIN;
571
572 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
573 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
574 return rto_min;
575}
576
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577/* Compute the actual receive window we are currently advertising.
578 * Rcv_nxt can be after the window if our peer push more data
579 * than the offered window.
580 */
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800581static inline u32 tcp_receive_window(const struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582{
583 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
584
585 if (win < 0)
586 win = 0;
587 return (u32) win;
588}
589
590/* Choose a new window, without checks for shrinking, and without
591 * scaling applied to the result. The caller does these things
592 * if necessary. This is a "raw" window selection.
593 */
594extern u32 __tcp_select_window(struct sock *sk);
595
596/* TCP timestamps are only 32-bits, this causes a slight
597 * complication on 64-bit systems since we store a snapshot
Stephen Hemminger31f34262005-11-15 15:17:10 -0800598 * of jiffies in the buffer control blocks below. We decided
599 * to use only the low 32-bits of jiffies and hide the ugly
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 * casts with the following macro.
601 */
602#define tcp_time_stamp ((__u32)(jiffies))
603
Stephen Hemmingercaa20d9a2005-11-10 17:13:47 -0800604/* This is what the send packet queuing engine uses to pass
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 * TCP per-packet control information to the transmission
606 * code. We also store the host-order sequence numbers in
607 * here too. This is 36 bytes on 32-bit architectures,
608 * 40 bytes on 64-bit machines, if this grows please adjust
609 * skbuff.h:skbuff->cb[xxx] size appropriately.
610 */
611struct tcp_skb_cb {
612 union {
613 struct inet_skb_parm h4;
614#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
615 struct inet6_skb_parm h6;
616#endif
617 } header; /* For incoming frames */
618 __u32 seq; /* Starting sequence number */
619 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
620 __u32 when; /* used to compute rtt's */
621 __u8 flags; /* TCP header flags. */
622
623 /* NOTE: These must match up to the flags byte in a
624 * real TCP header.
625 */
626#define TCPCB_FLAG_FIN 0x01
627#define TCPCB_FLAG_SYN 0x02
628#define TCPCB_FLAG_RST 0x04
629#define TCPCB_FLAG_PSH 0x08
630#define TCPCB_FLAG_ACK 0x10
631#define TCPCB_FLAG_URG 0x20
632#define TCPCB_FLAG_ECE 0x40
633#define TCPCB_FLAG_CWR 0x80
634
635 __u8 sacked; /* State flags for SACK/FACK. */
636#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
637#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
638#define TCPCB_LOST 0x04 /* SKB is lost */
639#define TCPCB_TAGBITS 0x07 /* All tag bits */
640
641#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
642#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 __u32 ack_seq; /* Sequence number ACK'd */
645};
646
647#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
648
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649/* Due to TSO, an SKB can be composed of multiple actual
650 * packets. To keep these tracked properly, we use this.
651 */
652static inline int tcp_skb_pcount(const struct sk_buff *skb)
653{
Herbert Xu79671682006-06-22 02:40:14 -0700654 return skb_shinfo(skb)->gso_segs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655}
656
657/* This is valid iff tcp_skb_pcount() > 1. */
658static inline int tcp_skb_mss(const struct sk_buff *skb)
659{
Herbert Xu79671682006-06-22 02:40:14 -0700660 return skb_shinfo(skb)->gso_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661}
662
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700663/* Events passed to congestion control interface */
664enum tcp_ca_event {
665 CA_EVENT_TX_START, /* first transmit when no packets in flight */
666 CA_EVENT_CWND_RESTART, /* congestion window restart */
667 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
668 CA_EVENT_FRTO, /* fast recovery timeout */
669 CA_EVENT_LOSS, /* loss timeout */
670 CA_EVENT_FAST_ACK, /* in sequence ack */
671 CA_EVENT_SLOW_ACK, /* other ack */
672};
673
674/*
675 * Interface for adding new TCP congestion control handlers
676 */
677#define TCP_CA_NAME_MAX 16
Stephen Hemminger3ff825b2006-11-09 16:32:06 -0800678#define TCP_CA_MAX 128
679#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
680
Stephen Hemminger164891a2007-04-23 22:26:16 -0700681#define TCP_CONG_NON_RESTRICTED 0x1
682#define TCP_CONG_RTT_STAMP 0x2
683
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700684struct tcp_congestion_ops {
685 struct list_head list;
Stephen Hemminger164891a2007-04-23 22:26:16 -0700686 unsigned long flags;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700687
688 /* initialize private data (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300689 void (*init)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700690 /* cleanup private data (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300691 void (*release)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700692
693 /* return slow start threshold (required) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300694 u32 (*ssthresh)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700695 /* lower bound for congestion window (optional) */
Stephen Hemminger72dc5b92006-06-05 17:30:08 -0700696 u32 (*min_cwnd)(const struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700697 /* do new cwnd calculation (required) */
Ilpo Järvinenc3a05c62007-12-02 00:47:59 +0200698 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700699 /* call before changing ca_state (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300700 void (*set_state)(struct sock *sk, u8 new_state);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700701 /* call when cwnd event occurs (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300702 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700703 /* new value of cwnd after loss (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300704 u32 (*undo_cwnd)(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700705 /* hook for packet ack accounting (optional) */
Stephen Hemminger30cfd0b2007-07-25 23:49:34 -0700706 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
Arnaldo Carvalho de Melo73c1f4a2005-08-12 12:51:49 -0300707 /* get info for inet_diag (optional) */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300708 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700709
710 char name[TCP_CA_NAME_MAX];
711 struct module *owner;
712};
713
714extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
715extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
716
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300717extern void tcp_init_congestion_control(struct sock *sk);
718extern void tcp_cleanup_congestion_control(struct sock *sk);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700719extern int tcp_set_default_congestion_control(const char *name);
720extern void tcp_get_default_congestion_control(char *name);
Stephen Hemminger3ff825b2006-11-09 16:32:06 -0800721extern void tcp_get_available_congestion_control(char *buf, size_t len);
Stephen Hemmingerce7bc3b2006-11-09 16:35:15 -0800722extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
723extern int tcp_set_allowed_congestion_control(char *allowed);
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300724extern int tcp_set_congestion_control(struct sock *sk, const char *name);
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800725extern void tcp_slow_start(struct tcp_sock *tp);
Ilpo Järvinen758ce5c2009-02-28 04:44:37 +0000726extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700727
Stephen Hemminger5f8ef482005-06-23 20:37:36 -0700728extern struct tcp_congestion_ops tcp_init_congestion_ops;
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300729extern u32 tcp_reno_ssthresh(struct sock *sk);
Ilpo Järvinenc3a05c62007-12-02 00:47:59 +0200730extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
Stephen Hemminger72dc5b92006-06-05 17:30:08 -0700731extern u32 tcp_reno_min_cwnd(const struct sock *sk);
David S. Millera8acfba2005-06-23 23:45:02 -0700732extern struct tcp_congestion_ops tcp_reno;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700733
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300734static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700735{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300736 struct inet_connection_sock *icsk = inet_csk(sk);
737
738 if (icsk->icsk_ca_ops->set_state)
739 icsk->icsk_ca_ops->set_state(sk, ca_state);
740 icsk->icsk_ca_state = ca_state;
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700741}
742
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300743static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700744{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300745 const struct inet_connection_sock *icsk = inet_csk(sk);
746
747 if (icsk->icsk_ca_ops->cwnd_event)
748 icsk->icsk_ca_ops->cwnd_event(sk, event);
Stephen Hemminger317a76f2005-06-23 12:19:55 -0700749}
750
Ilpo Järvinene60402d2007-08-09 15:14:46 +0300751/* These functions determine how the current flow behaves in respect of SACK
752 * handling. SACK is negotiated with the peer, and therefore it can vary
753 * between different flows.
754 *
755 * tcp_is_sack - SACK enabled
756 * tcp_is_reno - No SACK
757 * tcp_is_fack - FACK enabled, implies SACK enabled
758 */
759static inline int tcp_is_sack(const struct tcp_sock *tp)
760{
761 return tp->rx_opt.sack_ok;
762}
763
764static inline int tcp_is_reno(const struct tcp_sock *tp)
765{
766 return !tcp_is_sack(tp);
767}
768
769static inline int tcp_is_fack(const struct tcp_sock *tp)
770{
771 return tp->rx_opt.sack_ok & 2;
772}
773
774static inline void tcp_enable_fack(struct tcp_sock *tp)
775{
776 tp->rx_opt.sack_ok |= 2;
777}
778
Ilpo Järvinen83ae4082007-08-09 14:37:30 +0300779static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
780{
781 return tp->sacked_out + tp->lost_out;
782}
783
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784/* This determines how many packets are "in the network" to the best
785 * of our knowledge. In many cases it is conservative, but where
786 * detailed information is available from the receiver (via SACK
787 * blocks etc.) we can make more aggressive calculations.
788 *
789 * Use this for decisions involving congestion control, use just
790 * tp->packets_out to determine if the send queue is empty or not.
791 *
792 * Read this equation as:
793 *
794 * "Packets sent once on transmission queue" MINUS
795 * "Packets left network, but not honestly ACKed yet" PLUS
796 * "Packets fast retransmitted"
797 */
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800798static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799{
Ilpo Järvinen83ae4082007-08-09 14:37:30 +0300800 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801}
802
Ilpo Järvinen0b6a05c2009-09-15 01:30:10 -0700803#define TCP_INFINITE_SSTHRESH 0x7fffffff
804
805static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
806{
807 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
808}
809
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
811 * The exception is rate halving phase, when cwnd is decreasing towards
812 * ssthresh.
813 */
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300814static inline __u32 tcp_current_ssthresh(const struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815{
Arnaldo Carvalho de Melo6687e982005-08-10 04:03:31 -0300816 const struct tcp_sock *tp = tcp_sk(sk);
817 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 return tp->snd_ssthresh;
819 else
820 return max(tp->snd_ssthresh,
821 ((tp->snd_cwnd >> 1) +
822 (tp->snd_cwnd >> 2)));
823}
824
Ilpo Järvinenb9c45952007-07-27 16:36:17 +0300825/* Use define here intentionally to get WARN_ON location shown at the caller */
826#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827
Ilpo Järvinen3cfe3ba2007-02-27 10:09:49 -0800828extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
830
831/* Slow start with delack produces 3 packets of burst, so that
John Heffnerdd9e0dd2008-04-15 15:26:39 -0700832 * it is safe "de facto". This will be the default - same as
833 * the default reordering threshold - but if reordering increases,
834 * we must be able to allow cwnd to burst at least this much in order
835 * to not pull it back when holes are filled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 */
837static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
838{
John Heffnerdd9e0dd2008-04-15 15:26:39 -0700839 return tp->reordering;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840}
841
Ilpo Järvinen90840de2007-12-31 04:48:41 -0800842/* Returns end sequence number of the receiver's advertised window */
843static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
844{
845 return tp->snd_una + tp->snd_wnd;
846}
Ilpo Järvinencea14e02008-01-12 03:19:12 -0800847extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
Stephen Hemmingerf4805ed2005-11-10 16:53:30 -0800848
Chuck Leverc1bd24b2007-10-23 21:08:54 -0700849static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800850 const struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851{
852 if (skb->len < mss)
853 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
854}
855
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700856static inline void tcp_check_probe_timer(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857{
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700858 struct tcp_sock *tp = tcp_sk(sk);
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700859 const struct inet_connection_sock *icsk = inet_csk(sk);
Ilpo Järvinen9e412ba2007-04-20 22:18:02 -0700860
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700861 if (!tp->packets_out && !icsk->icsk_pending)
Arnaldo Carvalho de Melo3f421ba2005-08-09 20:11:08 -0700862 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
863 icsk->icsk_rto, TCP_RTO_MAX);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864}
865
Hantzis Fotisee7537b2009-03-02 22:42:02 -0800866static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867{
868 tp->snd_wl1 = seq;
869}
870
Hantzis Fotisee7537b2009-03-02 22:42:02 -0800871static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872{
873 tp->snd_wl1 = seq;
874}
875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876/*
877 * Calculate(/check) TCP checksum
878 */
Frederik Deweerdtba7808e2007-02-04 20:15:27 -0800879static inline __sum16 tcp_v4_check(int len, __be32 saddr,
880 __be32 daddr, __wsum base)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881{
882 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
883}
884
Al Virob51655b2006-11-14 21:40:42 -0800885static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886{
Herbert Xufb286bb2005-11-10 13:01:24 -0800887 return __skb_checksum_complete(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888}
889
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800890static inline int tcp_checksum_complete(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891{
Herbert Xu60476372007-04-09 11:59:39 -0700892 return !skb_csum_unnecessary(skb) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 __tcp_checksum_complete(skb);
894}
895
896/* Prequeue for VJ style copy to user, combined with checksumming. */
897
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800898static inline void tcp_prequeue_init(struct tcp_sock *tp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899{
900 tp->ucopy.task = NULL;
901 tp->ucopy.len = 0;
902 tp->ucopy.memory = 0;
903 skb_queue_head_init(&tp->ucopy.prequeue);
Chris Leech97fc2f02006-05-23 17:55:33 -0700904#ifdef CONFIG_NET_DMA
905 tp->ucopy.dma_chan = NULL;
906 tp->ucopy.wakeup = 0;
907 tp->ucopy.pinned_list = NULL;
908 tp->ucopy.dma_cookie = 0;
909#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910}
911
912/* Packet is added to VJ-style prequeue for processing in process
913 * context, if a reader task is waiting. Apparently, this exciting
914 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
915 * failed somewhere. Latency? Burstiness? Well, at least now we will
916 * see, why it failed. 8)8) --ANK
917 *
918 * NOTE: is this not too big to inline?
919 */
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800920static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921{
922 struct tcp_sock *tp = tcp_sk(sk);
923
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000924 if (sysctl_tcp_low_latency || !tp->ucopy.task)
925 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000927 __skb_queue_tail(&tp->ucopy.prequeue, skb);
928 tp->ucopy.memory += skb->truesize;
929 if (tp->ucopy.memory > sk->sk_rcvbuf) {
930 struct sk_buff *skb1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000932 BUG_ON(sock_owned_by_user(sk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000934 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
935 sk_backlog_rcv(sk, skb1);
936 NET_INC_STATS_BH(sock_net(sk),
937 LINUX_MIB_TCPPREQUEUEDROPPED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 }
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000939
940 tp->ucopy.memory = 0;
941 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
Mike Galbraithc839d302010-03-03 04:46:50 +0000942 wake_up_interruptible_sync_poll(sk->sk_sleep,
Eric Dumazet7aedec22009-05-07 07:20:39 +0000943 POLLIN | POLLRDNORM | POLLRDBAND);
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000944 if (!inet_csk_ack_scheduled(sk))
945 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
David S. Miller22f6dac2009-05-08 02:48:30 -0700946 (3 * tcp_rto_min(sk)) / 4,
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000947 TCP_RTO_MAX);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 }
Eric Dumazetf5f8d862009-05-07 07:08:38 +0000949 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950}
951
952
953#undef STATE_TRACE
954
955#ifdef STATE_TRACE
956static const char *statename[]={
957 "Unused","Established","Syn Sent","Syn Recv",
958 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
959 "Close Wait","Last ACK","Listen","Closing"
960};
961#endif
Ilpo Järvinen490d5042008-01-12 03:17:20 -0800962extern void tcp_set_state(struct sock *sk, int state);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963
Andi Kleen4ac02ba2007-04-20 17:11:46 -0700964extern void tcp_done(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800966static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967{
968 rx_opt->dsack = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 rx_opt->num_sacks = 0;
970}
971
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972/* Determine a window scaling and initial window to offer. */
973extern void tcp_select_initial_window(int __space, __u32 mss,
974 __u32 *rcv_wnd, __u32 *window_clamp,
laurent chavey31d12922009-12-15 11:15:28 +0000975 int wscale_ok, __u8 *rcv_wscale,
976 __u32 init_rcv_wnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
978static inline int tcp_win_from_space(int space)
979{
980 return sysctl_tcp_adv_win_scale<=0 ?
981 (space>>(-sysctl_tcp_adv_win_scale)) :
982 space - (space>>sysctl_tcp_adv_win_scale);
983}
984
985/* Note: caller must be prepared to deal with negative returns */
986static inline int tcp_space(const struct sock *sk)
987{
988 return tcp_win_from_space(sk->sk_rcvbuf -
989 atomic_read(&sk->sk_rmem_alloc));
990}
991
992static inline int tcp_full_space(const struct sock *sk)
993{
994 return tcp_win_from_space(sk->sk_rcvbuf);
995}
996
Stephen Hemminger40efc6f2006-01-03 16:03:49 -0800997static inline void tcp_openreq_init(struct request_sock *req,
998 struct tcp_options_received *rx_opt,
999 struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000{
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -07001001 struct inet_request_sock *ireq = inet_rsk(req);
1002
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
Florian Westphal4dfc2812008-04-10 03:12:40 -07001004 req->cookie_ts = 0;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -07001005 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 req->mss = rx_opt->mss_clamp;
1007 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -07001008 ireq->tstamp_ok = rx_opt->tstamp_ok;
1009 ireq->sack_ok = rx_opt->sack_ok;
1010 ireq->snd_wscale = rx_opt->snd_wscale;
1011 ireq->wscale_ok = rx_opt->wscale_ok;
1012 ireq->acked = 0;
1013 ireq->ecn_ok = 0;
Arnaldo Carvalho de Meloaa8223c2007-04-10 21:04:22 -07001014 ireq->rmt_port = tcp_hdr(skb)->source;
KOVACS Krisztiana3116ac52008-10-01 07:46:49 -07001015 ireq->loc_port = tcp_hdr(skb)->dest;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016}
1017
Pavel Emelyanov5c52ba12008-07-16 20:28:10 -07001018extern void tcp_enter_memory_pressure(struct sock *sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1021{
1022 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1023}
1024
1025static inline int keepalive_time_when(const struct tcp_sock *tp)
1026{
1027 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1028}
1029
Eric Dumazetdf19a622009-08-28 23:48:54 -07001030static inline int keepalive_probes(const struct tcp_sock *tp)
1031{
1032 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1033}
1034
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001035static inline int tcp_fin_time(const struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036{
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001037 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1038 const int rto = inet_csk(sk)->icsk_rto;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -07001040 if (fin_timeout < (rto << 2) - (rto >> 1))
1041 fin_timeout = (rto << 2) - (rto >> 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042
1043 return fin_timeout;
1044}
1045
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001046static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1047 int paws_win)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048{
Ilpo Järvinenc887e6d2009-03-14 14:23:03 +00001049 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1050 return 1;
1051 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1052 return 1;
1053
1054 return 0;
1055}
1056
1057static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1058 int rst)
1059{
1060 if (tcp_paws_check(rx_opt, 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 return 0;
1062
1063 /* RST segments are not recommended to carry timestamp,
1064 and, if they do, it is recommended to ignore PAWS because
1065 "their cleanup function should take precedence over timestamps."
1066 Certainly, it is mistake. It is necessary to understand the reasons
1067 of this constraint to relax it: if peer reboots, clock may go
1068 out-of-sync and half-open connections will not be reset.
1069 Actually, the problem would be not existing if all
1070 the implementations followed draft about maintaining clock
1071 via reboots. Linux-2.2 DOES NOT!
1072
1073 However, we can relax time bounds for RST segments to MSL.
1074 */
James Morris9d729f72007-03-04 16:12:44 -08001075 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 return 0;
1077 return 1;
1078}
1079
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080#define TCP_CHECK_TIMER(sk) do { } while (0)
1081
Pavel Emelyanova9c193292008-07-16 20:21:42 -07001082static inline void tcp_mib_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083{
1084 /* See RFC 2012 */
Pavel Emelyanovcf1100a2008-07-16 20:27:38 -07001085 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1086 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1087 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1088 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089}
1090
Ilpo Järvinen5af4ec22007-09-20 11:30:48 -07001091/* from STCP */
Ilpo Järvinenef9da472008-09-20 21:25:15 -07001092static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
David S. Miller0800f172007-09-20 11:40:37 -07001093{
Stephen Hemminger6a438bb2005-11-10 17:14:59 -08001094 tp->lost_skb_hint = NULL;
1095 tp->scoreboard_skb_hint = NULL;
Ilpo Järvinenef9da472008-09-20 21:25:15 -07001096}
1097
1098static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1099{
1100 tcp_clear_retrans_hints_partial(tp);
Stephen Hemminger6a438bb2005-11-10 17:14:59 -08001101 tp->retransmit_skb_hint = NULL;
Ilpo Järvinenb7689202007-09-20 11:37:19 -07001102}
1103
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001104/* MD5 Signature */
1105struct crypto_hash;
1106
1107/* - key database */
1108struct tcp_md5sig_key {
1109 u8 *key;
1110 u8 keylen;
1111};
1112
1113struct tcp4_md5sig_key {
David S. Millerf8ab18d2007-09-28 15:18:35 -07001114 struct tcp_md5sig_key base;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001115 __be32 addr;
1116};
1117
1118struct tcp6_md5sig_key {
David S. Millerf8ab18d2007-09-28 15:18:35 -07001119 struct tcp_md5sig_key base;
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001120#if 0
1121 u32 scope_id; /* XXX */
1122#endif
1123 struct in6_addr addr;
1124};
1125
1126/* - sock block */
1127struct tcp_md5sig_info {
1128 struct tcp4_md5sig_key *keys4;
1129#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1130 struct tcp6_md5sig_key *keys6;
1131 u32 entries6;
1132 u32 alloced6;
1133#endif
1134 u32 entries4;
1135 u32 alloced4;
1136};
1137
1138/* - pseudo header */
1139struct tcp4_pseudohdr {
1140 __be32 saddr;
1141 __be32 daddr;
1142 __u8 pad;
1143 __u8 protocol;
1144 __be16 len;
1145};
1146
1147struct tcp6_pseudohdr {
1148 struct in6_addr saddr;
1149 struct in6_addr daddr;
1150 __be32 len;
1151 __be32 protocol; /* including padding */
1152};
1153
1154union tcp_md5sum_block {
1155 struct tcp4_pseudohdr ip4;
1156#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1157 struct tcp6_pseudohdr ip6;
1158#endif
1159};
1160
1161/* - pool: digest algorithm, hash description and scratch buffer */
1162struct tcp_md5sig_pool {
1163 struct hash_desc md5_desc;
1164 union tcp_md5sum_block md5_blk;
1165};
1166
1167#define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1168
1169/* - functions */
Adam Langley49a72df2008-07-19 00:01:42 -07001170extern int tcp_v4_md5_hash_skb(char *md5_hash,
1171 struct tcp_md5sig_key *key,
1172 struct sock *sk,
1173 struct request_sock *req,
1174 struct sk_buff *skb);
YOSHIFUJI Hideaki8d26d762008-04-17 13:19:16 +09001175
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001176extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1177 struct sock *addr_sk);
1178
1179extern int tcp_v4_md5_do_add(struct sock *sk,
1180 __be32 addr,
1181 u8 *newkey,
1182 u8 newkeylen);
1183
1184extern int tcp_v4_md5_do_del(struct sock *sk,
Al Viro8e5200f2006-11-20 18:06:37 -08001185 __be32 addr);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001186
YOSHIFUJI Hideaki9501f972008-04-18 12:45:16 +09001187#ifdef CONFIG_TCP_MD5SIG
1188#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1189 &(struct tcp_md5sig_key) { \
1190 .key = (twsk)->tw_md5_key, \
1191 .keylen = (twsk)->tw_md5_keylen, \
1192 } : NULL)
1193#else
1194#define tcp_twsk_md5_key(twsk) NULL
1195#endif
1196
Tejun Heo7d720c32010-02-16 15:20:26 +00001197extern struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001198extern void tcp_free_md5sig_pool(void);
1199
1200extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1201extern void __tcp_put_md5sig_pool(void);
Adam Langley49a72df2008-07-19 00:01:42 -07001202extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1203extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1204 unsigned header_len);
1205extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1206 struct tcp_md5sig_key *key);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001207
1208static inline
1209struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1210{
1211 int cpu = get_cpu();
1212 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1213 if (!ret)
1214 put_cpu();
1215 return ret;
1216}
1217
1218static inline void tcp_put_md5sig_pool(void)
1219{
1220 __tcp_put_md5sig_pool();
1221 put_cpu();
1222}
1223
David S. Millerfe067e82007-03-07 12:12:44 -08001224/* write queue abstraction */
1225static inline void tcp_write_queue_purge(struct sock *sk)
1226{
1227 struct sk_buff *skb;
1228
1229 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
Hideo Aoki3ab224b2007-12-31 00:11:19 -08001230 sk_wmem_free_skb(sk, skb);
1231 sk_mem_reclaim(sk);
Ilpo Järvinen8818a9d2009-12-02 22:24:02 -08001232 tcp_clear_all_retrans_hints(tcp_sk(sk));
David S. Millerfe067e82007-03-07 12:12:44 -08001233}
1234
1235static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1236{
David S. Millercd07a8e2008-09-23 00:50:13 -07001237 return skb_peek(&sk->sk_write_queue);
David S. Millerfe067e82007-03-07 12:12:44 -08001238}
1239
1240static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1241{
David S. Millercd07a8e2008-09-23 00:50:13 -07001242 return skb_peek_tail(&sk->sk_write_queue);
David S. Millerfe067e82007-03-07 12:12:44 -08001243}
1244
1245static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1246{
David S. Millercd07a8e2008-09-23 00:50:13 -07001247 return skb_queue_next(&sk->sk_write_queue, skb);
David S. Millerfe067e82007-03-07 12:12:44 -08001248}
1249
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08001250static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1251{
1252 return skb_queue_prev(&sk->sk_write_queue, skb);
1253}
1254
David S. Millerfe067e82007-03-07 12:12:44 -08001255#define tcp_for_write_queue(skb, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001256 skb_queue_walk(&(sk)->sk_write_queue, skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001257
1258#define tcp_for_write_queue_from(skb, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001259 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
David S. Millerfe067e82007-03-07 12:12:44 -08001260
Ilpo Järvinen234b6862007-12-02 00:48:02 +02001261#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
David S. Millercd07a8e2008-09-23 00:50:13 -07001262 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
Ilpo Järvinen234b6862007-12-02 00:48:02 +02001263
David S. Millerfe067e82007-03-07 12:12:44 -08001264static inline struct sk_buff *tcp_send_head(struct sock *sk)
1265{
1266 return sk->sk_send_head;
1267}
1268
David S. Millercd07a8e2008-09-23 00:50:13 -07001269static inline bool tcp_skb_is_last(const struct sock *sk,
1270 const struct sk_buff *skb)
1271{
1272 return skb_queue_is_last(&sk->sk_write_queue, skb);
1273}
1274
David S. Millerfe067e82007-03-07 12:12:44 -08001275static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1276{
David S. Millercd07a8e2008-09-23 00:50:13 -07001277 if (tcp_skb_is_last(sk, skb))
David S. Millerfe067e82007-03-07 12:12:44 -08001278 sk->sk_send_head = NULL;
David S. Millercd07a8e2008-09-23 00:50:13 -07001279 else
1280 sk->sk_send_head = tcp_write_queue_next(sk, skb);
David S. Millerfe067e82007-03-07 12:12:44 -08001281}
1282
1283static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1284{
1285 if (sk->sk_send_head == skb_unlinked)
1286 sk->sk_send_head = NULL;
1287}
1288
1289static inline void tcp_init_send_head(struct sock *sk)
1290{
1291 sk->sk_send_head = NULL;
1292}
1293
1294static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1295{
1296 __skb_queue_tail(&sk->sk_write_queue, skb);
1297}
1298
1299static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1300{
1301 __tcp_add_write_queue_tail(sk, skb);
1302
1303 /* Queue it, remembering where we must start sending. */
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001304 if (sk->sk_send_head == NULL) {
David S. Millerfe067e82007-03-07 12:12:44 -08001305 sk->sk_send_head = skb;
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001306
1307 if (tcp_sk(sk)->highest_sack == NULL)
1308 tcp_sk(sk)->highest_sack = skb;
1309 }
David S. Millerfe067e82007-03-07 12:12:44 -08001310}
1311
1312static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1313{
1314 __skb_queue_head(&sk->sk_write_queue, skb);
1315}
1316
1317/* Insert buff after skb on the write queue of sk. */
1318static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1319 struct sk_buff *buff,
1320 struct sock *sk)
1321{
Gerrit Renker7de6c032008-04-14 00:05:09 -07001322 __skb_queue_after(&sk->sk_write_queue, skb, buff);
David S. Millerfe067e82007-03-07 12:12:44 -08001323}
1324
David S. Miller43f59c82008-09-21 21:28:51 -07001325/* Insert new before skb on the write queue of sk. */
David S. Millerfe067e82007-03-07 12:12:44 -08001326static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1327 struct sk_buff *skb,
1328 struct sock *sk)
1329{
David S. Miller43f59c82008-09-21 21:28:51 -07001330 __skb_queue_before(&sk->sk_write_queue, skb, new);
Ilpo Järvinen6e421412007-11-19 23:24:09 -08001331
1332 if (sk->sk_send_head == skb)
1333 sk->sk_send_head = new;
David S. Millerfe067e82007-03-07 12:12:44 -08001334}
1335
1336static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1337{
1338 __skb_unlink(skb, &sk->sk_write_queue);
1339}
1340
David S. Millerfe067e82007-03-07 12:12:44 -08001341static inline int tcp_write_queue_empty(struct sock *sk)
1342{
1343 return skb_queue_empty(&sk->sk_write_queue);
1344}
1345
Krishna Kumar12d50c42009-12-08 22:26:13 +00001346static inline void tcp_push_pending_frames(struct sock *sk)
1347{
1348 if (tcp_send_head(sk)) {
1349 struct tcp_sock *tp = tcp_sk(sk);
1350
1351 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
1352 }
1353}
1354
Ilpo Järvinena47e5a92007-11-15 19:41:46 -08001355/* Start sequence of the highest skb with SACKed bit, valid only if
1356 * sacked > 0 or when the caller has ensured validity by itself.
1357 */
1358static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1359{
1360 if (!tp->sacked_out)
1361 return tp->snd_una;
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001362
1363 if (tp->highest_sack == NULL)
1364 return tp->snd_nxt;
1365
Ilpo Järvinena47e5a92007-11-15 19:41:46 -08001366 return TCP_SKB_CB(tp->highest_sack)->seq;
1367}
1368
Ilpo Järvinen6859d492007-12-02 00:48:06 +02001369static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1370{
1371 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1372 tcp_write_queue_next(sk, skb);
1373}
1374
1375static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1376{
1377 return tcp_sk(sk)->highest_sack;
1378}
1379
1380static inline void tcp_highest_sack_reset(struct sock *sk)
1381{
1382 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1383}
1384
1385/* Called when old skb is about to be deleted (to be combined with new skb) */
1386static inline void tcp_highest_sack_combine(struct sock *sk,
1387 struct sk_buff *old,
1388 struct sk_buff *new)
1389{
1390 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1391 tcp_sk(sk)->highest_sack = new;
1392}
1393
Andreas Petlund5aa4b322010-02-18 02:45:45 +00001394/* Determines whether this is a thin stream (which may suffer from
1395 * increased latency). Used to trigger latency-reducing mechanisms.
1396 */
1397static inline unsigned int tcp_stream_is_thin(struct tcp_sock *tp)
1398{
1399 return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp);
1400}
1401
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402/* /proc */
1403enum tcp_seq_states {
1404 TCP_SEQ_STATE_LISTENING,
1405 TCP_SEQ_STATE_OPENREQ,
1406 TCP_SEQ_STATE_ESTABLISHED,
1407 TCP_SEQ_STATE_TIME_WAIT,
1408};
1409
1410struct tcp_seq_afinfo {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 char *name;
1412 sa_family_t family;
Denis V. Lunev68fcadd2008-04-13 22:13:30 -07001413 struct file_operations seq_fops;
Denis V. Lunev9427c4b2008-04-13 22:12:13 -07001414 struct seq_operations seq_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415};
1416
1417struct tcp_iter_state {
Denis V. Luneva4146b12008-04-13 22:11:14 -07001418 struct seq_net_private p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 sa_family_t family;
1420 enum tcp_seq_states state;
1421 struct sock *syn_wait_sk;
1422 int bucket, sbucket, num, uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423};
1424
Daniel Lezcano6f8b13b2008-03-21 04:14:45 -07001425extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1426extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001428extern struct request_sock_ops tcp_request_sock_ops;
Glenn Griffinc6aefaf2008-02-07 21:49:26 -08001429extern struct request_sock_ops tcp6_request_sock_ops;
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001430
Brian Haley7d06b2e2008-06-14 17:04:49 -07001431extern void tcp_v4_destroy_sock(struct sock *sk);
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001432
Herbert Xua430a432006-07-08 13:34:56 -07001433extern int tcp_v4_gso_send_check(struct sk_buff *skb);
Herbert Xu576a30e2006-06-27 13:22:38 -07001434extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
Herbert Xubf296b12008-12-15 23:43:36 -08001435extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1436 struct sk_buff *skb);
1437extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1438 struct sk_buff *skb);
1439extern int tcp_gro_complete(struct sk_buff *skb);
1440extern int tcp4_gro_complete(struct sk_buff *skb);
Herbert Xuf4c50d92006-06-22 03:02:40 -07001441
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001442#ifdef CONFIG_PROC_FS
1443extern int tcp4_proc_init(void);
1444extern void tcp4_proc_exit(void);
1445#endif
1446
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001447/* TCP af-specific functions */
1448struct tcp_sock_af_ops {
1449#ifdef CONFIG_TCP_MD5SIG
1450 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1451 struct sock *addr_sk);
1452 int (*calc_md5_hash) (char *location,
1453 struct tcp_md5sig_key *md5,
1454 struct sock *sk,
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001455 struct request_sock *req,
Adam Langley49a72df2008-07-19 00:01:42 -07001456 struct sk_buff *skb);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001457 int (*md5_add) (struct sock *sk,
1458 struct sock *addr_sk,
1459 u8 *newkey,
1460 u8 len);
1461 int (*md5_parse) (struct sock *sk,
1462 char __user *optval,
1463 int optlen);
1464#endif
1465};
1466
1467struct tcp_request_sock_ops {
1468#ifdef CONFIG_TCP_MD5SIG
1469 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1470 struct request_sock *req);
John Dykstrae3afe7b2009-07-16 05:04:51 +00001471 int (*calc_md5_hash) (char *location,
1472 struct tcp_md5sig_key *md5,
1473 struct sock *sk,
1474 struct request_sock *req,
1475 struct sk_buff *skb);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -08001476#endif
1477};
1478
William Allen Simpsonda5c78c2009-12-02 18:12:09 +00001479/* Using SHA1 for now, define some constants.
1480 */
1481#define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS)
1482#define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4)
1483#define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS)
1484
1485extern int tcp_cookie_generator(u32 *bakery);
1486
William Allen Simpson435cf552009-12-02 18:17:05 +00001487/**
1488 * struct tcp_cookie_values - each socket needs extra space for the
1489 * cookies, together with (optional) space for any SYN data.
1490 *
1491 * A tcp_sock contains a pointer to the current value, and this is
1492 * cloned to the tcp_timewait_sock.
1493 *
1494 * @cookie_pair: variable data from the option exchange.
1495 *
1496 * @cookie_desired: user specified tcpct_cookie_desired. Zero
1497 * indicates default (sysctl_tcp_cookie_size).
1498 * After cookie sent, remembers size of cookie.
1499 * Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX.
1500 *
1501 * @s_data_desired: user specified tcpct_s_data_desired. When the
1502 * constant payload is specified (@s_data_constant),
1503 * holds its length instead.
1504 * Range 0 to TCP_MSS_DESIRED.
1505 *
1506 * @s_data_payload: constant data that is to be included in the
1507 * payload of SYN or SYNACK segments when the
1508 * cookie option is present.
1509 */
1510struct tcp_cookie_values {
1511 struct kref kref;
1512 u8 cookie_pair[TCP_COOKIE_PAIR_SIZE];
1513 u8 cookie_pair_size;
1514 u8 cookie_desired;
1515 u16 s_data_desired:11,
1516 s_data_constant:1,
1517 s_data_in:1,
1518 s_data_out:1,
1519 s_data_unused:2;
1520 u8 s_data_payload[0];
1521};
1522
1523static inline void tcp_cookie_values_release(struct kref *kref)
1524{
1525 kfree(container_of(kref, struct tcp_cookie_values, kref));
1526}
1527
1528/* The length of constant payload data. Note that s_data_desired is
1529 * overloaded, depending on s_data_constant: either the length of constant
1530 * data (returned here) or the limit on variable data.
1531 */
1532static inline int tcp_s_data_size(const struct tcp_sock *tp)
1533{
1534 return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant)
1535 ? tp->cookie_values->s_data_desired
1536 : 0;
1537}
1538
1539/**
1540 * struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace.
1541 *
1542 * As tcp_request_sock has already been extended in other places, the
1543 * only remaining method is to pass stack values along as function
1544 * parameters. These parameters are not needed after sending SYNACK.
1545 *
1546 * @cookie_bakery: cryptographic secret and message workspace.
1547 *
1548 * @cookie_plus: bytes in authenticator/cookie option, copied from
1549 * struct tcp_options_received (above).
1550 */
1551struct tcp_extend_values {
1552 struct request_values rv;
1553 u32 cookie_bakery[COOKIE_WORKSPACE_WORDS];
1554 u8 cookie_plus:6,
1555 cookie_out_never:1,
1556 cookie_in_always:1;
1557};
1558
1559static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp)
1560{
1561 return (struct tcp_extend_values *)rvp;
1562}
1563
Denis V. Lunev9b0f9762008-02-29 11:13:15 -08001564extern void tcp_v4_init(void);
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001565extern void tcp_init(void);
1566
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567#endif /* _TCP_H */