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tcp: advertise MSS requested by user
[linux-2.6-block.git] / include / net / tcp.h
CommitLineData
1da177e4
LT		 1/*
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 *
02c30a84 10 * Authors: Ross Biro
1da177e4
LT		 11 * 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
1da177e4
LT		 24#include <linux/list.h>
25#include <linux/tcp.h>
26#include <linux/slab.h>
27#include <linux/cache.h>
28#include <linux/percpu.h>
fb286bb2 29#include <linux/skbuff.h>
97fc2f08 30#include <linux/dmaengine.h>
cfb6eeb4 31#include <linux/crypto.h>
c6aefafb 32#include <linux/cryptohash.h>
3f421baa
ACM		 33
34#include <net/inet_connection_sock.h>
295ff7ed 35#include <net/inet_timewait_sock.h>
77d8bf9c 36#include <net/inet_hashtables.h>
1da177e4 37#include <net/checksum.h>
2e6599cb 38#include <net/request_sock.h>
1da177e4
LT		 39#include <net/sock.h>
40#include <net/snmp.h>
41#include <net/ip.h>
c752f073 42#include <net/tcp_states.h>
bdf1ee5d 43#include <net/inet_ecn.h>
c752f073 44
1da177e4
LT		 45#include <linux/seq_file.h>
46
6e04e021 47extern struct inet_hashinfo tcp_hashinfo;
1da177e4 48
1da177e4 49extern atomic_t tcp_orphan_count;
1da177e4 50extern void tcp_time_wait(struct sock *sk, int state, int timeo);
1da177e4 51
1da177e4 52#define MAX_TCP_HEADER (128 + MAX_HEADER)
33ad798c 53#define MAX_TCP_OPTION_SPACE 40
1da177e4
LT		 54
55/*
56 * Never offer a window over 32767 without using window scaling. Some
57 * poor stacks do signed 16bit maths!
58 */
59#define MAX_TCP_WINDOW 32767U
60
61/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
62#define TCP_MIN_MSS 88U
63
64/* Minimal RCV_MSS. */
65#define TCP_MIN_RCVMSS 536U
66
5d424d5a
JH		 67/* The least MTU to use for probing */
68#define TCP_BASE_MSS 512
69
1da177e4
LT		 70/* After receiving this amount of duplicate ACKs fast retransmit starts. */
71#define TCP_FASTRETRANS_THRESH 3
72
73/* Maximal reordering. */
74#define TCP_MAX_REORDERING 127
75
76/* Maximal number of ACKs sent quickly to accelerate slow-start. */
77#define TCP_MAX_QUICKACKS 16U
78
79/* urg_data states */
80#define TCP_URG_VALID 0x0100
81#define TCP_URG_NOTYET 0x0200
82#define TCP_URG_READ 0x0400
83
84#define TCP_RETR1 3 /*
85 * This is how many retries it does before it
86 * tries to figure out if the gateway is
87 * down. Minimal RFC value is 3; it corresponds
88 * to ~3sec-8min depending on RTO.
89 */
90
91#define TCP_RETR2 15 /*
92 * This should take at least
93 * 90 minutes to time out.
94 * RFC1122 says that the limit is 100 sec.
95 * 15 is ~13-30min depending on RTO.
96 */
97
98#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
caa20d9a 99 * connection: ~180sec is RFC minimum */
1da177e4
LT		 100
101#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
caa20d9a 102 * connection: ~180sec is RFC minimum */
1da177e4
LT		 103
104
105#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
106 * socket. 7 is ~50sec-16min.
107 */
108
109
110#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
111 * state, about 60 seconds */
112#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
113 /* BSD style FIN_WAIT2 deadlock breaker.
114 * It used to be 3min, new value is 60sec,
115 * to combine FIN-WAIT-2 timeout with
116 * TIME-WAIT timer.
117 */
118
119#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
120#if HZ >= 100
121#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
122#define TCP_ATO_MIN ((unsigned)(HZ/25))
123#else
124#define TCP_DELACK_MIN 4U
125#define TCP_ATO_MIN 4U
126#endif
127#define TCP_RTO_MAX ((unsigned)(120*HZ))
128#define TCP_RTO_MIN ((unsigned)(HZ/5))
129#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
130
131#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
132 * for local resources.
133 */
134
135#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
136#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
137#define TCP_KEEPALIVE_INTVL (75*HZ)
138
139#define MAX_TCP_KEEPIDLE 32767
140#define MAX_TCP_KEEPINTVL 32767
141#define MAX_TCP_KEEPCNT 127
142#define MAX_TCP_SYNCNT 127
143
144#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
1da177e4
LT		 145
146#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
147#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
148 * after this time. It should be equal
149 * (or greater than) TCP_TIMEWAIT_LEN
150 * to provide reliability equal to one
151 * provided by timewait state.
152 */
153#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
154 * timestamps. It must be less than
155 * minimal timewait lifetime.
156 */
1da177e4
LT		 157/*
158 * TCP option
159 */
160
161#define TCPOPT_NOP 1 /* Padding */
162#define TCPOPT_EOL 0 /* End of options */
163#define TCPOPT_MSS 2 /* Segment size negotiating */
164#define TCPOPT_WINDOW 3 /* Window scaling */
165#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
166#define TCPOPT_SACK 5 /* SACK Block */
167#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
cfb6eeb4 168#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
1da177e4
LT		 169
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
cfb6eeb4 178#define TCPOLEN_MD5SIG 18
1da177e4
LT		 179
180/* But this is what stacks really send out. */
181#define TCPOLEN_TSTAMP_ALIGNED 12
182#define TCPOLEN_WSCALE_ALIGNED 4
183#define TCPOLEN_SACKPERM_ALIGNED 4
184#define TCPOLEN_SACK_BASE 2
185#define TCPOLEN_SACK_BASE_ALIGNED 4
186#define TCPOLEN_SACK_PERBLOCK 8
cfb6eeb4 187#define TCPOLEN_MD5SIG_ALIGNED 20
33ad798c 188#define TCPOLEN_MSS_ALIGNED 4
1da177e4 189
1da177e4
LT		 190/* Flags in tp->nonagle */
191#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
192#define TCP_NAGLE_CORK 2 /* Socket is corked */
caa20d9a 193#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
1da177e4 194
295ff7ed
ACM		 195extern struct inet_timewait_death_row tcp_death_row;
196
1da177e4 197/* sysctl variables for tcp */
1da177e4
LT		 198extern int sysctl_tcp_timestamps;
199extern int sysctl_tcp_window_scaling;
200extern int sysctl_tcp_sack;
201extern int sysctl_tcp_fin_timeout;
1da177e4
LT		 202extern int sysctl_tcp_keepalive_time;
203extern int sysctl_tcp_keepalive_probes;
204extern int sysctl_tcp_keepalive_intvl;
205extern int sysctl_tcp_syn_retries;
206extern int sysctl_tcp_synack_retries;
207extern int sysctl_tcp_retries1;
208extern int sysctl_tcp_retries2;
209extern int sysctl_tcp_orphan_retries;
210extern int sysctl_tcp_syncookies;
211extern int sysctl_tcp_retrans_collapse;
212extern int sysctl_tcp_stdurg;
213extern int sysctl_tcp_rfc1337;
214extern int sysctl_tcp_abort_on_overflow;
215extern int sysctl_tcp_max_orphans;
1da177e4
LT		 216extern int sysctl_tcp_fack;
217extern int sysctl_tcp_reordering;
218extern int sysctl_tcp_ecn;
219extern int sysctl_tcp_dsack;
220extern int sysctl_tcp_mem[3];
221extern int sysctl_tcp_wmem[3];
222extern int sysctl_tcp_rmem[3];
223extern int sysctl_tcp_app_win;
224extern int sysctl_tcp_adv_win_scale;
225extern int sysctl_tcp_tw_reuse;
226extern int sysctl_tcp_frto;
3cfe3baa 227extern int sysctl_tcp_frto_response;
1da177e4 228extern int sysctl_tcp_low_latency;
95937825 229extern int sysctl_tcp_dma_copybreak;
1da177e4 230extern int sysctl_tcp_nometrics_save;
1da177e4
LT		 231extern int sysctl_tcp_moderate_rcvbuf;
232extern int sysctl_tcp_tso_win_divisor;
9772efb9 233extern int sysctl_tcp_abc;
5d424d5a
JH		 234extern int sysctl_tcp_mtu_probing;
235extern int sysctl_tcp_base_mss;
15d99e02 236extern int sysctl_tcp_workaround_signed_windows;
35089bb2 237extern int sysctl_tcp_slow_start_after_idle;
886236c1 238extern int sysctl_tcp_max_ssthresh;
1da177e4
LT		 239
240extern atomic_t tcp_memory_allocated;
241extern atomic_t tcp_sockets_allocated;
242extern int tcp_memory_pressure;
243
1da177e4
LT		 244/*
245 * The next routines deal with comparing 32 bit unsigned ints
246 * and worry about wraparound (automatic with unsigned arithmetic).
247 */
248
249static inline int before(__u32 seq1, __u32 seq2)
250{
0d630cc0 251 return (__s32)(seq1-seq2) < 0;
1da177e4 252}
9a036b9c 253#define after(seq2, seq1) before(seq1, seq2)
1da177e4
LT		 254
255/* is s2<=s1<=s3 ? */
256static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
257{
258 return seq3 - seq2 >= seq1 - seq2;
259}
260
e4fd5da3
PE		 261static inline int tcp_too_many_orphans(struct sock *sk, int num)
262{
263 return (num > sysctl_tcp_max_orphans) ||
264 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
265 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
266}
1da177e4
LT		 267
268extern struct proto tcp_prot;
269
57ef42d5
PE		 270#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
271#define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
272#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
273#define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
1da177e4 274
1da177e4
LT		 275extern void tcp_v4_err(struct sk_buff *skb, u32);
276
277extern void tcp_shutdown (struct sock *sk, int how);
278
279extern int tcp_v4_rcv(struct sk_buff *skb);
280
281extern int tcp_v4_remember_stamp(struct sock *sk);
282
8feaf0c0 283extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
1da177e4 284
3516ffb0 285extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
1da177e4
LT		 286 struct msghdr *msg, size_t size);
287extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
288
289extern int tcp_ioctl(struct sock *sk,
290 int cmd,
291 unsigned long arg);
292
293extern int tcp_rcv_state_process(struct sock *sk,
294 struct sk_buff *skb,
295 struct tcphdr *th,
296 unsigned len);
297
298extern int tcp_rcv_established(struct sock *sk,
299 struct sk_buff *skb,
300 struct tcphdr *th,
301 unsigned len);
302
303extern void tcp_rcv_space_adjust(struct sock *sk);
304
0e4b4992
CL		 305extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
306
6d6ee43e
ACM		 307extern int tcp_twsk_unique(struct sock *sk,
308 struct sock *sktw, void *twp);
309
cfb6eeb4
YH		 310extern void tcp_twsk_destructor(struct sock *sk);
311
9c55e01c
JA		 312extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
313 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
314
463c84b9
ACM		 315static inline void tcp_dec_quickack_mode(struct sock *sk,
316 const unsigned int pkts)
1da177e4 317{
463c84b9 318 struct inet_connection_sock *icsk = inet_csk(sk);
fc6415bc 319
463c84b9
ACM		 320 if (icsk->icsk_ack.quick) {
321 if (pkts >= icsk->icsk_ack.quick) {
322 icsk->icsk_ack.quick = 0;
fc6415bc 323 /* Leaving quickack mode we deflate ATO. */
463c84b9 324 icsk->icsk_ack.ato = TCP_ATO_MIN;
fc6415bc 325 } else
463c84b9 326 icsk->icsk_ack.quick -= pkts;
1da177e4
LT		 327 }
328}
329
463c84b9 330extern void tcp_enter_quickack_mode(struct sock *sk);
1da177e4 331
1da177e4
LT		 332static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
333{
334 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
335}
336
bdf1ee5d
IJ		 337#define TCP_ECN_OK 1
338#define TCP_ECN_QUEUE_CWR 2
339#define TCP_ECN_DEMAND_CWR 4
340
341static __inline__ void
342TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
343{
344 if (sysctl_tcp_ecn && th->ece && th->cwr)
345 inet_rsk(req)->ecn_ok = 1;
346}
347
1da177e4
LT		 348enum tcp_tw_status
349{
350 TCP_TW_SUCCESS = 0,
351 TCP_TW_RST = 1,
352 TCP_TW_ACK = 2,
353 TCP_TW_SYN = 3
354};
355
356
8feaf0c0 357extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
1da177e4 358 struct sk_buff *skb,
8feaf0c0 359 const struct tcphdr *th);
1da177e4
LT		 360
361extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
60236fdd
ACM		 362 struct request_sock *req,
363 struct request_sock **prev);
1da177e4
LT		 364extern int tcp_child_process(struct sock *parent,
365 struct sock *child,
366 struct sk_buff *skb);
46d0de4e 367extern int tcp_use_frto(struct sock *sk);
1da177e4
LT		 368extern void tcp_enter_frto(struct sock *sk);
369extern void tcp_enter_loss(struct sock *sk, int how);
370extern void tcp_clear_retrans(struct tcp_sock *tp);
371extern void tcp_update_metrics(struct sock *sk);
372
373extern void tcp_close(struct sock *sk,
374 long timeout);
1da177e4
LT		 375extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
376
377extern int tcp_getsockopt(struct sock *sk, int level,
378 int optname,
379 char __user *optval,
380 int __user *optlen);
381extern int tcp_setsockopt(struct sock *sk, int level,
382 int optname, char __user *optval,
383 int optlen);
3fdadf7d
DM		 384extern int compat_tcp_getsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int __user *optlen);
387extern int compat_tcp_setsockopt(struct sock *sk,
388 int level, int optname,
389 char __user *optval, int optlen);
1da177e4
LT		 390extern void tcp_set_keepalive(struct sock *sk, int val);
391extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
392 struct msghdr *msg,
393 size_t len, int nonblock,
394 int flags, int *addr_len);
395
1da177e4
LT		 396extern void tcp_parse_options(struct sk_buff *skb,
397 struct tcp_options_received *opt_rx,
398 int estab);
399
7d5d5525
YH		 400extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
401
1da177e4
LT		 402/*
403 * TCP v4 functions exported for the inet6 API
404 */
405
8292a17a 406extern void tcp_v4_send_check(struct sock *sk, int len,
1da177e4
LT		 407 struct sk_buff *skb);
408
409extern int tcp_v4_conn_request(struct sock *sk,
410 struct sk_buff *skb);
411
412extern struct sock * tcp_create_openreq_child(struct sock *sk,
60236fdd 413 struct request_sock *req,
1da177e4
LT		 414 struct sk_buff *skb);
415
416extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
417 struct sk_buff *skb,
60236fdd 418 struct request_sock *req,
1da177e4
LT		 419 struct dst_entry *dst);
420
421extern int tcp_v4_do_rcv(struct sock *sk,
422 struct sk_buff *skb);
423
424extern int tcp_v4_connect(struct sock *sk,
425 struct sockaddr *uaddr,
426 int addr_len);
427
428extern int tcp_connect(struct sock *sk);
429
430extern struct sk_buff * tcp_make_synack(struct sock *sk,
431 struct dst_entry *dst,
60236fdd 432 struct request_sock *req);
1da177e4
LT		 433
434extern int tcp_disconnect(struct sock *sk, int flags);
435
1da177e4 436
1da177e4 437/* From syncookies.c */
2051f11f 438extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
1da177e4
LT		 439extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
440 struct ip_options *opt);
441extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
442 __u16 *mss);
443
4dfc2817
FW		 444extern __u32 cookie_init_timestamp(struct request_sock *req);
445extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
446
c6aefafb
GG		 447/* From net/ipv6/syncookies.c */
448extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
449extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
450 __u16 *mss);
451
1da177e4
LT		 452/* tcp_output.c */
453
9e412ba7
IJ		 454extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
455 int nonagle);
456extern int tcp_may_send_now(struct sock *sk);
1da177e4
LT		 457extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
458extern void tcp_xmit_retransmit_queue(struct sock *);
459extern void tcp_simple_retransmit(struct sock *);
460extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
6475be16 461extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
1da177e4
LT		 462
463extern void tcp_send_probe0(struct sock *);
464extern void tcp_send_partial(struct sock *);
465extern int tcp_write_wakeup(struct sock *);
466extern void tcp_send_fin(struct sock *sk);
dd0fc66f 467extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
1da177e4 468extern int tcp_send_synack(struct sock *);
c1b4a7e6 469extern void tcp_push_one(struct sock *, unsigned int mss_now);
1da177e4
LT		 470extern void tcp_send_ack(struct sock *sk);
471extern void tcp_send_delayed_ack(struct sock *sk);
472
a762a980
DM		 473/* tcp_input.c */
474extern void tcp_cwnd_application_limited(struct sock *sk);
006f582c
IJ		 475extern void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp,
476 struct sk_buff *skb);
a762a980 477
1da177e4
LT		 478/* tcp_timer.c */
479extern void tcp_init_xmit_timers(struct sock *);
463c84b9
ACM		 480static inline void tcp_clear_xmit_timers(struct sock *sk)
481{
482 inet_csk_clear_xmit_timers(sk);
483}
1da177e4 484
1da177e4
LT		 485extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
486extern unsigned int tcp_current_mss(struct sock *sk, int large);
487
17b085ea 488/* tcp.c */
1da177e4
LT		 489extern void tcp_get_info(struct sock *, struct tcp_info *);
490
491/* Read 'sendfile()'-style from a TCP socket */
492typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
493 unsigned int, size_t);
494extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
495 sk_read_actor_t recv_actor);
496
40efc6fa 497extern void tcp_initialize_rcv_mss(struct sock *sk);
1da177e4 498
5d424d5a
JH		 499extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
500extern int tcp_mss_to_mtu(struct sock *sk, int mss);
501extern void tcp_mtup_init(struct sock *sk);
502
40efc6fa 503static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
1da177e4
LT		 504{
505 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
506 ntohl(TCP_FLAG_ACK) |
507 snd_wnd);
508}
509
40efc6fa 510static inline void tcp_fast_path_on(struct tcp_sock *tp)
1da177e4
LT		 511{
512 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
513}
514
9e412ba7 515static inline void tcp_fast_path_check(struct sock *sk)
1da177e4 516{
9e412ba7
IJ		 517 struct tcp_sock *tp = tcp_sk(sk);
518
b03efcfb 519 if (skb_queue_empty(&tp->out_of_order_queue) &&
1da177e4
LT		 520 tp->rcv_wnd &&
521 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
522 !tp->urg_data)
523 tcp_fast_path_on(tp);
524}
525
526/* Compute the actual receive window we are currently advertising.
527 * Rcv_nxt can be after the window if our peer push more data
528 * than the offered window.
529 */
40efc6fa 530static inline u32 tcp_receive_window(const struct tcp_sock *tp)
1da177e4
LT		 531{
532 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
533
534 if (win < 0)
535 win = 0;
536 return (u32) win;
537}
538
539/* Choose a new window, without checks for shrinking, and without
540 * scaling applied to the result. The caller does these things
541 * if necessary. This is a "raw" window selection.
542 */
543extern u32 __tcp_select_window(struct sock *sk);
544
545/* TCP timestamps are only 32-bits, this causes a slight
546 * complication on 64-bit systems since we store a snapshot
31f34269
SH		 547 * of jiffies in the buffer control blocks below. We decided
548 * to use only the low 32-bits of jiffies and hide the ugly
1da177e4
LT		 549 * casts with the following macro.
550 */
551#define tcp_time_stamp ((__u32)(jiffies))
552
caa20d9a 553/* This is what the send packet queuing engine uses to pass
1da177e4
LT		 554 * TCP per-packet control information to the transmission
555 * code. We also store the host-order sequence numbers in
556 * here too. This is 36 bytes on 32-bit architectures,
557 * 40 bytes on 64-bit machines, if this grows please adjust
558 * skbuff.h:skbuff->cb[xxx] size appropriately.
559 */
560struct tcp_skb_cb {
561 union {
562 struct inet_skb_parm h4;
563#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
564 struct inet6_skb_parm h6;
565#endif
566 } header; /* For incoming frames */
567 __u32 seq; /* Starting sequence number */
568 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
569 __u32 when; /* used to compute rtt's */
570 __u8 flags; /* TCP header flags. */
571
572 /* NOTE: These must match up to the flags byte in a
573 * real TCP header.
574 */
575#define TCPCB_FLAG_FIN 0x01
576#define TCPCB_FLAG_SYN 0x02
577#define TCPCB_FLAG_RST 0x04
578#define TCPCB_FLAG_PSH 0x08
579#define TCPCB_FLAG_ACK 0x10
580#define TCPCB_FLAG_URG 0x20
581#define TCPCB_FLAG_ECE 0x40
582#define TCPCB_FLAG_CWR 0x80
583
584 __u8 sacked; /* State flags for SACK/FACK. */
585#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
586#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
587#define TCPCB_LOST 0x04 /* SKB is lost */
588#define TCPCB_TAGBITS 0x07 /* All tag bits */
589
590#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
591#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
592
1da177e4
LT		 593 __u16 urg_ptr; /* Valid w/URG flags is set. */
594 __u32 ack_seq; /* Sequence number ACK'd */
595};
596
597#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
598
1da177e4
LT		 599/* Due to TSO, an SKB can be composed of multiple actual
600 * packets. To keep these tracked properly, we use this.
601 */
602static inline int tcp_skb_pcount(const struct sk_buff *skb)
603{
7967168c 604 return skb_shinfo(skb)->gso_segs;
1da177e4
LT		 605}
606
607/* This is valid iff tcp_skb_pcount() > 1. */
608static inline int tcp_skb_mss(const struct sk_buff *skb)
609{
7967168c 610 return skb_shinfo(skb)->gso_size;
1da177e4
LT		 611}
612
af610b4c 613static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
1da177e4
LT		 614{
615 if (*count) {
af610b4c 616 *count -= decr;
1da177e4
LT		 617 if ((int)*count < 0)
618 *count = 0;
619 }
620}
621
af610b4c
IJ		 622static inline void tcp_dec_pcount_approx(__u32 *count,
623 const struct sk_buff *skb)
624{
625 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
626}
627
317a76f9
SH		 628/* Events passed to congestion control interface */
629enum tcp_ca_event {
630 CA_EVENT_TX_START, /* first transmit when no packets in flight */
631 CA_EVENT_CWND_RESTART, /* congestion window restart */
632 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
633 CA_EVENT_FRTO, /* fast recovery timeout */
634 CA_EVENT_LOSS, /* loss timeout */
635 CA_EVENT_FAST_ACK, /* in sequence ack */
636 CA_EVENT_SLOW_ACK, /* other ack */
637};
638
639/*
640 * Interface for adding new TCP congestion control handlers
641 */
642#define TCP_CA_NAME_MAX 16
3ff825b2
SH		 643#define TCP_CA_MAX 128
644#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
645
164891aa
SH		 646#define TCP_CONG_NON_RESTRICTED 0x1
647#define TCP_CONG_RTT_STAMP 0x2
648
317a76f9
SH		 649struct tcp_congestion_ops {
650 struct list_head list;
164891aa 651 unsigned long flags;
317a76f9
SH		 652
653 /* initialize private data (optional) */
6687e988 654 void (*init)(struct sock *sk);
317a76f9 655 /* cleanup private data (optional) */
6687e988 656 void (*release)(struct sock *sk);
317a76f9
SH		 657
658 /* return slow start threshold (required) */
6687e988 659 u32 (*ssthresh)(struct sock *sk);
317a76f9 660 /* lower bound for congestion window (optional) */
72dc5b92 661 u32 (*min_cwnd)(const struct sock *sk);
317a76f9 662 /* do new cwnd calculation (required) */
c3a05c60 663 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
317a76f9 664 /* call before changing ca_state (optional) */
6687e988 665 void (*set_state)(struct sock *sk, u8 new_state);
317a76f9 666 /* call when cwnd event occurs (optional) */
6687e988 667 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
317a76f9 668 /* new value of cwnd after loss (optional) */
6687e988 669 u32 (*undo_cwnd)(struct sock *sk);
317a76f9 670 /* hook for packet ack accounting (optional) */
30cfd0ba 671 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
73c1f4a0 672 /* get info for inet_diag (optional) */
6687e988 673 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
317a76f9
SH		 674
675 char name[TCP_CA_NAME_MAX];
676 struct module *owner;
677};
678
679extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
680extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
681
6687e988
ACM		 682extern void tcp_init_congestion_control(struct sock *sk);
683extern void tcp_cleanup_congestion_control(struct sock *sk);
317a76f9
SH		 684extern int tcp_set_default_congestion_control(const char *name);
685extern void tcp_get_default_congestion_control(char *name);
3ff825b2 686extern void tcp_get_available_congestion_control(char *buf, size_t len);
ce7bc3bf
SH		 687extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
688extern int tcp_set_allowed_congestion_control(char *allowed);
6687e988 689extern int tcp_set_congestion_control(struct sock *sk, const char *name);
40efc6fa 690extern void tcp_slow_start(struct tcp_sock *tp);
317a76f9 691
5f8ef48d 692extern struct tcp_congestion_ops tcp_init_congestion_ops;
6687e988 693extern u32 tcp_reno_ssthresh(struct sock *sk);
c3a05c60 694extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
72dc5b92 695extern u32 tcp_reno_min_cwnd(const struct sock *sk);
a8acfbac 696extern struct tcp_congestion_ops tcp_reno;
317a76f9 697
6687e988 698static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
317a76f9 699{
6687e988
ACM		 700 struct inet_connection_sock *icsk = inet_csk(sk);
701
702 if (icsk->icsk_ca_ops->set_state)
703 icsk->icsk_ca_ops->set_state(sk, ca_state);
704 icsk->icsk_ca_state = ca_state;
317a76f9
SH		 705}
706
6687e988 707static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
317a76f9 708{
6687e988
ACM		 709 const struct inet_connection_sock *icsk = inet_csk(sk);
710
711 if (icsk->icsk_ca_ops->cwnd_event)
712 icsk->icsk_ca_ops->cwnd_event(sk, event);
317a76f9
SH		 713}
714
e60402d0
IJ		 715/* These functions determine how the current flow behaves in respect of SACK
716 * handling. SACK is negotiated with the peer, and therefore it can vary
717 * between different flows.
718 *
719 * tcp_is_sack - SACK enabled
720 * tcp_is_reno - No SACK
721 * tcp_is_fack - FACK enabled, implies SACK enabled
722 */
723static inline int tcp_is_sack(const struct tcp_sock *tp)
724{
725 return tp->rx_opt.sack_ok;
726}
727
728static inline int tcp_is_reno(const struct tcp_sock *tp)
729{
730 return !tcp_is_sack(tp);
731}
732
733static inline int tcp_is_fack(const struct tcp_sock *tp)
734{
735 return tp->rx_opt.sack_ok & 2;
736}
737
738static inline void tcp_enable_fack(struct tcp_sock *tp)
739{
740 tp->rx_opt.sack_ok |= 2;
741}
742
83ae4088
IJ		 743static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
744{
745 return tp->sacked_out + tp->lost_out;
746}
747
1da177e4
LT		 748/* This determines how many packets are "in the network" to the best
749 * of our knowledge. In many cases it is conservative, but where
750 * detailed information is available from the receiver (via SACK
751 * blocks etc.) we can make more aggressive calculations.
752 *
753 * Use this for decisions involving congestion control, use just
754 * tp->packets_out to determine if the send queue is empty or not.
755 *
756 * Read this equation as:
757 *
758 * "Packets sent once on transmission queue" MINUS
759 * "Packets left network, but not honestly ACKed yet" PLUS
760 * "Packets fast retransmitted"
761 */
40efc6fa 762static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
1da177e4 763{
83ae4088 764 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
1da177e4
LT		 765}
766
882bebaa
IJ		 767extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
768
1da177e4
LT		 769/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
770 * The exception is rate halving phase, when cwnd is decreasing towards
771 * ssthresh.
772 */
6687e988 773static inline __u32 tcp_current_ssthresh(const struct sock *sk)
1da177e4 774{
6687e988
ACM		 775 const struct tcp_sock *tp = tcp_sk(sk);
776 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
1da177e4
LT		 777 return tp->snd_ssthresh;
778 else
779 return max(tp->snd_ssthresh,
780 ((tp->snd_cwnd >> 1) +
781 (tp->snd_cwnd >> 2)));
782}
783
b9c4595b
IJ		 784/* Use define here intentionally to get WARN_ON location shown at the caller */
785#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
1da177e4 786
3cfe3baa 787extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
1da177e4
LT		 788extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
789
790/* Slow start with delack produces 3 packets of burst, so that
dd9e0dda
JH		 791 * it is safe "de facto". This will be the default - same as
792 * the default reordering threshold - but if reordering increases,
793 * we must be able to allow cwnd to burst at least this much in order
794 * to not pull it back when holes are filled.
1da177e4
LT		 795 */
796static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
797{
dd9e0dda 798 return tp->reordering;
1da177e4
LT		 799}
800
90840def
IJ		 801/* Returns end sequence number of the receiver's advertised window */
802static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
803{
804 return tp->snd_una + tp->snd_wnd;
805}
cea14e0e 806extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
f4805ede 807
c1bd24b7 808static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
40efc6fa 809 const struct sk_buff *skb)
1da177e4
LT		 810{
811 if (skb->len < mss)
812 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
813}
814
9e412ba7 815static inline void tcp_check_probe_timer(struct sock *sk)
1da177e4 816{
9e412ba7 817 struct tcp_sock *tp = tcp_sk(sk);
463c84b9 818 const struct inet_connection_sock *icsk = inet_csk(sk);
9e412ba7 819
463c84b9 820 if (!tp->packets_out && !icsk->icsk_pending)
3f421baa
ACM		 821 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
822 icsk->icsk_rto, TCP_RTO_MAX);
1da177e4
LT		 823}
824
9e412ba7 825static inline void tcp_push_pending_frames(struct sock *sk)
1da177e4 826{
9e412ba7
IJ		 827 struct tcp_sock *tp = tcp_sk(sk);
828
829 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
1da177e4
LT		 830}
831
40efc6fa 832static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
1da177e4
LT		 833{
834 tp->snd_wl1 = seq;
835}
836
40efc6fa 837static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
1da177e4
LT		 838{
839 tp->snd_wl1 = seq;
840}
841
1da177e4
LT		 842/*
843 * Calculate(/check) TCP checksum
844 */
ba7808ea
FD		 845static inline __sum16 tcp_v4_check(int len, __be32 saddr,
846 __be32 daddr, __wsum base)
1da177e4
LT		 847{
848 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
849}
850
b51655b9 851static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
1da177e4 852{
fb286bb2 853 return __skb_checksum_complete(skb);
1da177e4
LT		 854}
855
40efc6fa 856static inline int tcp_checksum_complete(struct sk_buff *skb)
1da177e4 857{
60476372 858 return !skb_csum_unnecessary(skb) &&
1da177e4
LT		 859 __tcp_checksum_complete(skb);
860}
861
862/* Prequeue for VJ style copy to user, combined with checksumming. */
863
40efc6fa 864static inline void tcp_prequeue_init(struct tcp_sock *tp)
1da177e4
LT		 865{
866 tp->ucopy.task = NULL;
867 tp->ucopy.len = 0;
868 tp->ucopy.memory = 0;
869 skb_queue_head_init(&tp->ucopy.prequeue);
97fc2f08
CL		 870#ifdef CONFIG_NET_DMA
871 tp->ucopy.dma_chan = NULL;
872 tp->ucopy.wakeup = 0;
873 tp->ucopy.pinned_list = NULL;
874 tp->ucopy.dma_cookie = 0;
875#endif
1da177e4
LT		 876}
877
878/* Packet is added to VJ-style prequeue for processing in process
879 * context, if a reader task is waiting. Apparently, this exciting
880 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
881 * failed somewhere. Latency? Burstiness? Well, at least now we will
882 * see, why it failed. 8)8) --ANK
883 *
884 * NOTE: is this not too big to inline?
885 */
40efc6fa 886static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1da177e4
LT		 887{
888 struct tcp_sock *tp = tcp_sk(sk);
889
890 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
891 __skb_queue_tail(&tp->ucopy.prequeue, skb);
892 tp->ucopy.memory += skb->truesize;
893 if (tp->ucopy.memory > sk->sk_rcvbuf) {
894 struct sk_buff *skb1;
895
896 BUG_ON(sock_owned_by_user(sk));
897
898 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
899 sk->sk_backlog_rcv(sk, skb1);
de0744af 900 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED);
1da177e4
LT		 901 }
902
903 tp->ucopy.memory = 0;
904 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
905 wake_up_interruptible(sk->sk_sleep);
463c84b9
ACM		 906 if (!inet_csk_ack_scheduled(sk))
907 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
3f421baa
ACM		 908 (3 * TCP_RTO_MIN) / 4,
909 TCP_RTO_MAX);
1da177e4
LT		 910 }
911 return 1;
912 }
913 return 0;
914}
915
916
917#undef STATE_TRACE
918
919#ifdef STATE_TRACE
920static const char *statename[]={
921 "Unused","Established","Syn Sent","Syn Recv",
922 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
923 "Close Wait","Last ACK","Listen","Closing"
924};
925#endif
490d5046 926extern void tcp_set_state(struct sock *sk, int state);
1da177e4 927
4ac02bab 928extern void tcp_done(struct sock *sk);
1da177e4 929
40efc6fa 930static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
1da177e4
LT		 931{
932 rx_opt->dsack = 0;
933 rx_opt->eff_sacks = 0;
934 rx_opt->num_sacks = 0;
935}
936
1da177e4
LT		 937/* Determine a window scaling and initial window to offer. */
938extern void tcp_select_initial_window(int __space, __u32 mss,
939 __u32 *rcv_wnd, __u32 *window_clamp,
940 int wscale_ok, __u8 *rcv_wscale);
941
942static inline int tcp_win_from_space(int space)
943{
944 return sysctl_tcp_adv_win_scale<=0 ?
945 (space>>(-sysctl_tcp_adv_win_scale)) :
946 space - (space>>sysctl_tcp_adv_win_scale);
947}
948
949/* Note: caller must be prepared to deal with negative returns */
950static inline int tcp_space(const struct sock *sk)
951{
952 return tcp_win_from_space(sk->sk_rcvbuf -
953 atomic_read(&sk->sk_rmem_alloc));
954}
955
956static inline int tcp_full_space(const struct sock *sk)
957{
958 return tcp_win_from_space(sk->sk_rcvbuf);
959}
960
40efc6fa
SH		 961static inline void tcp_openreq_init(struct request_sock *req,
962 struct tcp_options_received *rx_opt,
963 struct sk_buff *skb)
1da177e4 964{
2e6599cb
ACM		 965 struct inet_request_sock *ireq = inet_rsk(req);
966
1da177e4 967 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
4dfc2817 968 req->cookie_ts = 0;
2e6599cb 969 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1da177e4
LT		 970 req->mss = rx_opt->mss_clamp;
971 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
2e6599cb
ACM		 972 ireq->tstamp_ok = rx_opt->tstamp_ok;
973 ireq->sack_ok = rx_opt->sack_ok;
974 ireq->snd_wscale = rx_opt->snd_wscale;
975 ireq->wscale_ok = rx_opt->wscale_ok;
976 ireq->acked = 0;
977 ireq->ecn_ok = 0;
aa8223c7 978 ireq->rmt_port = tcp_hdr(skb)->source;
1da177e4
LT		 979}
980
5c52ba17 981extern void tcp_enter_memory_pressure(struct sock *sk);
1da177e4 982
1da177e4
LT		 983static inline int keepalive_intvl_when(const struct tcp_sock *tp)
984{
985 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
986}
987
988static inline int keepalive_time_when(const struct tcp_sock *tp)
989{
990 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
991}
992
463c84b9 993static inline int tcp_fin_time(const struct sock *sk)
1da177e4 994{
463c84b9
ACM		 995 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
996 const int rto = inet_csk(sk)->icsk_rto;
1da177e4 997
463c84b9
ACM		 998 if (fin_timeout < (rto << 2) - (rto >> 1))
999 fin_timeout = (rto << 2) - (rto >> 1);
1da177e4
LT		 1000
1001 return fin_timeout;
1002}
1003
1004static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1005{
1006 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1007 return 0;
9d729f72 1008 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1da177e4
LT		 1009 return 0;
1010
1011 /* RST segments are not recommended to carry timestamp,
1012 and, if they do, it is recommended to ignore PAWS because
1013 "their cleanup function should take precedence over timestamps."
1014 Certainly, it is mistake. It is necessary to understand the reasons
1015 of this constraint to relax it: if peer reboots, clock may go
1016 out-of-sync and half-open connections will not be reset.
1017 Actually, the problem would be not existing if all
1018 the implementations followed draft about maintaining clock
1019 via reboots. Linux-2.2 DOES NOT!
1020
1021 However, we can relax time bounds for RST segments to MSL.
1022 */
9d729f72 1023 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1da177e4
LT		 1024 return 0;
1025 return 1;
1026}
1027
1da177e4
LT		 1028#define TCP_CHECK_TIMER(sk) do { } while (0)
1029
a9c19329 1030static inline void tcp_mib_init(struct net *net)
1da177e4
LT		 1031{
1032 /* See RFC 2012 */
cf1100a7
PE		 1033 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1034 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1035 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1036 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1da177e4
LT		 1037}
1038
5af4ec23 1039/* from STCP */
ef9da47c 1040static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
0800f170 1041{
6a438bbe
SH		 1042 tp->lost_skb_hint = NULL;
1043 tp->scoreboard_skb_hint = NULL;
ef9da47c
IJ		 1044}
1045
1046static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1047{
1048 tcp_clear_retrans_hints_partial(tp);
6a438bbe 1049 tp->retransmit_skb_hint = NULL;
b7689205
IJ		 1050}
1051
cfb6eeb4
YH		 1052/* MD5 Signature */
1053struct crypto_hash;
1054
1055/* - key database */
1056struct tcp_md5sig_key {
1057 u8 *key;
1058 u8 keylen;
1059};
1060
1061struct tcp4_md5sig_key {
f8ab18d2 1062 struct tcp_md5sig_key base;
cfb6eeb4
YH		 1063 __be32 addr;
1064};
1065
1066struct tcp6_md5sig_key {
f8ab18d2 1067 struct tcp_md5sig_key base;
cfb6eeb4
YH		 1068#if 0
1069 u32 scope_id; /* XXX */
1070#endif
1071 struct in6_addr addr;
1072};
1073
1074/* - sock block */
1075struct tcp_md5sig_info {
1076 struct tcp4_md5sig_key *keys4;
1077#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1078 struct tcp6_md5sig_key *keys6;
1079 u32 entries6;
1080 u32 alloced6;
1081#endif
1082 u32 entries4;
1083 u32 alloced4;
1084};
1085
1086/* - pseudo header */
1087struct tcp4_pseudohdr {
1088 __be32 saddr;
1089 __be32 daddr;
1090 __u8 pad;
1091 __u8 protocol;
1092 __be16 len;
1093};
1094
1095struct tcp6_pseudohdr {
1096 struct in6_addr saddr;
1097 struct in6_addr daddr;
1098 __be32 len;
1099 __be32 protocol; /* including padding */
1100};
1101
1102union tcp_md5sum_block {
1103 struct tcp4_pseudohdr ip4;
1104#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1105 struct tcp6_pseudohdr ip6;
1106#endif
1107};
1108
1109/* - pool: digest algorithm, hash description and scratch buffer */
1110struct tcp_md5sig_pool {
1111 struct hash_desc md5_desc;
1112 union tcp_md5sum_block md5_blk;
1113};
1114
1115#define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1116
1117/* - functions */
49a72dfb
AL		 1118extern int tcp_v4_md5_hash_skb(char *md5_hash,
1119 struct tcp_md5sig_key *key,
1120 struct sock *sk,
1121 struct request_sock *req,
1122 struct sk_buff *skb);
1123
cfb6eeb4
YH		 1124extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1125 struct sock *addr_sk);
1126
1127extern int tcp_v4_md5_do_add(struct sock *sk,
1128 __be32 addr,
1129 u8 *newkey,
1130 u8 newkeylen);
1131
1132extern int tcp_v4_md5_do_del(struct sock *sk,
8e5200f5 1133 __be32 addr);
cfb6eeb4 1134
9501f972
YH		 1135#ifdef CONFIG_TCP_MD5SIG
1136#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1137 &(struct tcp_md5sig_key) { \
1138 .key = (twsk)->tw_md5_key, \
1139 .keylen = (twsk)->tw_md5_keylen, \
1140 } : NULL)
1141#else
1142#define tcp_twsk_md5_key(twsk) NULL
1143#endif
1144
cfb6eeb4
YH		 1145extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1146extern void tcp_free_md5sig_pool(void);
1147
1148extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1149extern void __tcp_put_md5sig_pool(void);
49a72dfb
AL		 1150extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1151extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1152 unsigned header_len);
1153extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1154 struct tcp_md5sig_key *key);
cfb6eeb4
YH		 1155
1156static inline
1157struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1158{
1159 int cpu = get_cpu();
1160 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1161 if (!ret)
1162 put_cpu();
1163 return ret;
1164}
1165
1166static inline void tcp_put_md5sig_pool(void)
1167{
1168 __tcp_put_md5sig_pool();
1169 put_cpu();
1170}
1171
fe067e8a
DM		 1172/* write queue abstraction */
1173static inline void tcp_write_queue_purge(struct sock *sk)
1174{
1175 struct sk_buff *skb;
1176
1177 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
3ab224be
HA		 1178 sk_wmem_free_skb(sk, skb);
1179 sk_mem_reclaim(sk);
fe067e8a
DM		 1180}
1181
1182static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1183{
1184 struct sk_buff *skb = sk->sk_write_queue.next;
1185 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1186 return NULL;
1187 return skb;
1188}
1189
1190static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1191{
1192 struct sk_buff *skb = sk->sk_write_queue.prev;
1193 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1194 return NULL;
1195 return skb;
1196}
1197
1198static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1199{
1200 return skb->next;
1201}
1202
1203#define tcp_for_write_queue(skb, sk) \
1204 for (skb = (sk)->sk_write_queue.next; \
1205 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1206 skb = skb->next)
1207
1208#define tcp_for_write_queue_from(skb, sk) \
1209 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1210 skb = skb->next)
1211
234b6860
IJ		 1212#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1213 for (tmp = skb->next; \
1214 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1215 skb = tmp, tmp = skb->next)
1216
fe067e8a
DM		 1217static inline struct sk_buff *tcp_send_head(struct sock *sk)
1218{
1219 return sk->sk_send_head;
1220}
1221
1222static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1223{
1224 sk->sk_send_head = skb->next;
1225 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1226 sk->sk_send_head = NULL;
1227}
1228
1229static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1230{
1231 if (sk->sk_send_head == skb_unlinked)
1232 sk->sk_send_head = NULL;
1233}
1234
1235static inline void tcp_init_send_head(struct sock *sk)
1236{
1237 sk->sk_send_head = NULL;
1238}
1239
1240static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1241{
1242 __skb_queue_tail(&sk->sk_write_queue, skb);
1243}
1244
1245static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1246{
1247 __tcp_add_write_queue_tail(sk, skb);
1248
1249 /* Queue it, remembering where we must start sending. */
6859d494 1250 if (sk->sk_send_head == NULL) {
fe067e8a 1251 sk->sk_send_head = skb;
6859d494
IJ		 1252
1253 if (tcp_sk(sk)->highest_sack == NULL)
1254 tcp_sk(sk)->highest_sack = skb;
1255 }
fe067e8a
DM		 1256}
1257
1258static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1259{
1260 __skb_queue_head(&sk->sk_write_queue, skb);
1261}
1262
1263/* Insert buff after skb on the write queue of sk. */
1264static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1265 struct sk_buff *buff,
1266 struct sock *sk)
1267{
7de6c033 1268 __skb_queue_after(&sk->sk_write_queue, skb, buff);
fe067e8a
DM		 1269}
1270
1271/* Insert skb between prev and next on the write queue of sk. */
1272static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1273 struct sk_buff *skb,
1274 struct sock *sk)
1275{
1276 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);