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[DCCP]: Initialize icsk_rto in dccp_v4_init_sock
[GitHub/mt8127/android_kernel_alcatel_ttab.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/config.h>
25#include <linux/list.h>
26#include <linux/tcp.h>
27#include <linux/slab.h>
28#include <linux/cache.h>
29#include <linux/percpu.h>
3f421baa
ACM		 30
31#include <net/inet_connection_sock.h>
77d8bf9c 32#include <net/inet_hashtables.h>
1da177e4 33#include <net/checksum.h>
2e6599cb 34#include <net/request_sock.h>
1da177e4
LT		 35#include <net/sock.h>
36#include <net/snmp.h>
37#include <net/ip.h>
c752f073
ACM		 38#include <net/tcp_states.h>
39
1da177e4
LT		 40#include <linux/seq_file.h>
41
6e04e021 42extern struct inet_hashinfo tcp_hashinfo;
1da177e4 43
1da177e4
LT		 44extern atomic_t tcp_orphan_count;
45extern int tcp_tw_count;
46extern void tcp_time_wait(struct sock *sk, int state, int timeo);
8feaf0c0 47extern void tcp_tw_deschedule(struct inet_timewait_sock *tw);
1da177e4 48
1da177e4
LT		 49#define MAX_TCP_HEADER (128 + MAX_HEADER)
50
51/*
52 * Never offer a window over 32767 without using window scaling. Some
53 * poor stacks do signed 16bit maths!
54 */
55#define MAX_TCP_WINDOW 32767U
56
57/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
58#define TCP_MIN_MSS 88U
59
60/* Minimal RCV_MSS. */
61#define TCP_MIN_RCVMSS 536U
62
63/* After receiving this amount of duplicate ACKs fast retransmit starts. */
64#define TCP_FASTRETRANS_THRESH 3
65
66/* Maximal reordering. */
67#define TCP_MAX_REORDERING 127
68
69/* Maximal number of ACKs sent quickly to accelerate slow-start. */
70#define TCP_MAX_QUICKACKS 16U
71
72/* urg_data states */
73#define TCP_URG_VALID 0x0100
74#define TCP_URG_NOTYET 0x0200
75#define TCP_URG_READ 0x0400
76
77#define TCP_RETR1 3 /*
78 * This is how many retries it does before it
79 * tries to figure out if the gateway is
80 * down. Minimal RFC value is 3; it corresponds
81 * to ~3sec-8min depending on RTO.
82 */
83
84#define TCP_RETR2 15 /*
85 * This should take at least
86 * 90 minutes to time out.
87 * RFC1122 says that the limit is 100 sec.
88 * 15 is ~13-30min depending on RTO.
89 */
90
91#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
92 * connection: ~180sec is RFC minumum */
93
94#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
95 * connection: ~180sec is RFC minumum */
96
97
98#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
99 * socket. 7 is ~50sec-16min.
100 */
101
102
103#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
104 * state, about 60 seconds */
105#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
106 /* BSD style FIN_WAIT2 deadlock breaker.
107 * It used to be 3min, new value is 60sec,
108 * to combine FIN-WAIT-2 timeout with
109 * TIME-WAIT timer.
110 */
111
112#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
113#if HZ >= 100
114#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
115#define TCP_ATO_MIN ((unsigned)(HZ/25))
116#else
117#define TCP_DELACK_MIN 4U
118#define TCP_ATO_MIN 4U
119#endif
120#define TCP_RTO_MAX ((unsigned)(120*HZ))
121#define TCP_RTO_MIN ((unsigned)(HZ/5))
122#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
123
124#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
125 * for local resources.
126 */
127
128#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
129#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
130#define TCP_KEEPALIVE_INTVL (75*HZ)
131
132#define MAX_TCP_KEEPIDLE 32767
133#define MAX_TCP_KEEPINTVL 32767
134#define MAX_TCP_KEEPCNT 127
135#define MAX_TCP_SYNCNT 127
136
137#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
138#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
139
140#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
141#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
142 * after this time. It should be equal
143 * (or greater than) TCP_TIMEWAIT_LEN
144 * to provide reliability equal to one
145 * provided by timewait state.
146 */
147#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
148 * timestamps. It must be less than
149 * minimal timewait lifetime.
150 */
151
152#define TCP_TW_RECYCLE_SLOTS_LOG 5
153#define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG)
154
155/* If time > 4sec, it is "slow" path, no recycling is required,
156 so that we select tick to get range about 4 seconds.
157 */
158
159#if HZ <= 16 || HZ > 4096
160# error Unsupported: HZ <= 16 or HZ > 4096
161#elif HZ <= 32
162# define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
163#elif HZ <= 64
164# define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG)
165#elif HZ <= 128
166# define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
167#elif HZ <= 256
168# define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG)
169#elif HZ <= 512
170# define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG)
171#elif HZ <= 1024
172# define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
173#elif HZ <= 2048
174# define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
175#else
176# define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
177#endif
1da177e4
LT		 178/*
179 * TCP option
180 */
181
182#define TCPOPT_NOP 1 /* Padding */
183#define TCPOPT_EOL 0 /* End of options */
184#define TCPOPT_MSS 2 /* Segment size negotiating */
185#define TCPOPT_WINDOW 3 /* Window scaling */
186#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
187#define TCPOPT_SACK 5 /* SACK Block */
188#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
189
190/*
191 * TCP option lengths
192 */
193
194#define TCPOLEN_MSS 4
195#define TCPOLEN_WINDOW 3
196#define TCPOLEN_SACK_PERM 2
197#define TCPOLEN_TIMESTAMP 10
198
199/* But this is what stacks really send out. */
200#define TCPOLEN_TSTAMP_ALIGNED 12
201#define TCPOLEN_WSCALE_ALIGNED 4
202#define TCPOLEN_SACKPERM_ALIGNED 4
203#define TCPOLEN_SACK_BASE 2
204#define TCPOLEN_SACK_BASE_ALIGNED 4
205#define TCPOLEN_SACK_PERBLOCK 8
206
1da177e4
LT		 207/* Flags in tp->nonagle */
208#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
209#define TCP_NAGLE_CORK 2 /* Socket is corked */
210#define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */
211
212/* sysctl variables for tcp */
1da177e4
LT		 213extern int sysctl_tcp_timestamps;
214extern int sysctl_tcp_window_scaling;
215extern int sysctl_tcp_sack;
216extern int sysctl_tcp_fin_timeout;
217extern int sysctl_tcp_tw_recycle;
218extern int sysctl_tcp_keepalive_time;
219extern int sysctl_tcp_keepalive_probes;
220extern int sysctl_tcp_keepalive_intvl;
221extern int sysctl_tcp_syn_retries;
222extern int sysctl_tcp_synack_retries;
223extern int sysctl_tcp_retries1;
224extern int sysctl_tcp_retries2;
225extern int sysctl_tcp_orphan_retries;
226extern int sysctl_tcp_syncookies;
227extern int sysctl_tcp_retrans_collapse;
228extern int sysctl_tcp_stdurg;
229extern int sysctl_tcp_rfc1337;
230extern int sysctl_tcp_abort_on_overflow;
231extern int sysctl_tcp_max_orphans;
232extern int sysctl_tcp_max_tw_buckets;
233extern int sysctl_tcp_fack;
234extern int sysctl_tcp_reordering;
235extern int sysctl_tcp_ecn;
236extern int sysctl_tcp_dsack;
237extern int sysctl_tcp_mem[3];
238extern int sysctl_tcp_wmem[3];
239extern int sysctl_tcp_rmem[3];
240extern int sysctl_tcp_app_win;
241extern int sysctl_tcp_adv_win_scale;
242extern int sysctl_tcp_tw_reuse;
243extern int sysctl_tcp_frto;
244extern int sysctl_tcp_low_latency;
1da177e4 245extern int sysctl_tcp_nometrics_save;
1da177e4
LT		 246extern int sysctl_tcp_moderate_rcvbuf;
247extern int sysctl_tcp_tso_win_divisor;
248
249extern atomic_t tcp_memory_allocated;
250extern atomic_t tcp_sockets_allocated;
251extern int tcp_memory_pressure;
252
1da177e4
LT		 253/*
254 * Pointers to address related TCP functions
255 * (i.e. things that depend on the address family)
256 */
257
258struct tcp_func {
259 int (*queue_xmit) (struct sk_buff *skb,
260 int ipfragok);
261
262 void (*send_check) (struct sock *sk,
263 struct tcphdr *th,
264 int len,
265 struct sk_buff *skb);
266
267 int (*rebuild_header) (struct sock *sk);
268
269 int (*conn_request) (struct sock *sk,
270 struct sk_buff *skb);
271
272 struct sock * (*syn_recv_sock) (struct sock *sk,
273 struct sk_buff *skb,
60236fdd 274 struct request_sock *req,
1da177e4
LT		 275 struct dst_entry *dst);
276
277 int (*remember_stamp) (struct sock *sk);
278
279 __u16 net_header_len;
280
281 int (*setsockopt) (struct sock *sk,
282 int level,
283 int optname,
284 char __user *optval,
285 int optlen);
286
287 int (*getsockopt) (struct sock *sk,
288 int level,
289 int optname,
290 char __user *optval,
291 int __user *optlen);
292
293
294 void (*addr2sockaddr) (struct sock *sk,
295 struct sockaddr *);
296
297 int sockaddr_len;
298};
299
300/*
301 * The next routines deal with comparing 32 bit unsigned ints
302 * and worry about wraparound (automatic with unsigned arithmetic).
303 */
304
305static inline int before(__u32 seq1, __u32 seq2)
306{
307 return (__s32)(seq1-seq2) < 0;
308}
309
310static inline int after(__u32 seq1, __u32 seq2)
311{
312 return (__s32)(seq2-seq1) < 0;
313}
314
315
316/* is s2<=s1<=s3 ? */
317static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
318{
319 return seq3 - seq2 >= seq1 - seq2;
320}
321
322
323extern struct proto tcp_prot;
324
325DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
326#define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
327#define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
328#define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
329#define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
330#define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
331#define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
332
1da177e4
LT		 333extern void tcp_v4_err(struct sk_buff *skb, u32);
334
335extern void tcp_shutdown (struct sock *sk, int how);
336
337extern int tcp_v4_rcv(struct sk_buff *skb);
338
339extern int tcp_v4_remember_stamp(struct sock *sk);
340
8feaf0c0 341extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
1da177e4
LT		 342
343extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
344 struct msghdr *msg, size_t size);
345extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
346
347extern int tcp_ioctl(struct sock *sk,
348 int cmd,
349 unsigned long arg);
350
351extern int tcp_rcv_state_process(struct sock *sk,
352 struct sk_buff *skb,
353 struct tcphdr *th,
354 unsigned len);
355
356extern int tcp_rcv_established(struct sock *sk,
357 struct sk_buff *skb,
358 struct tcphdr *th,
359 unsigned len);
360
361extern void tcp_rcv_space_adjust(struct sock *sk);
362
463c84b9
ACM		 363static inline void tcp_dec_quickack_mode(struct sock *sk,
364 const unsigned int pkts)
1da177e4 365{
463c84b9 366 struct inet_connection_sock *icsk = inet_csk(sk);
fc6415bc 367
463c84b9
ACM		 368 if (icsk->icsk_ack.quick) {
369 if (pkts >= icsk->icsk_ack.quick) {
370 icsk->icsk_ack.quick = 0;
fc6415bc 371 /* Leaving quickack mode we deflate ATO. */
463c84b9 372 icsk->icsk_ack.ato = TCP_ATO_MIN;
fc6415bc 373 } else
463c84b9 374 icsk->icsk_ack.quick -= pkts;
1da177e4
LT		 375 }
376}
377
463c84b9 378extern void tcp_enter_quickack_mode(struct sock *sk);
1da177e4 379
1da177e4
LT		 380static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
381{
382 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
383}
384
385enum tcp_tw_status
386{
387 TCP_TW_SUCCESS = 0,
388 TCP_TW_RST = 1,
389 TCP_TW_ACK = 2,
390 TCP_TW_SYN = 3
391};
392
393
8feaf0c0 394extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
1da177e4 395 struct sk_buff *skb,
8feaf0c0 396 const struct tcphdr *th);
1da177e4
LT		 397
398extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
60236fdd
ACM		 399 struct request_sock *req,
400 struct request_sock **prev);
1da177e4
LT		 401extern int tcp_child_process(struct sock *parent,
402 struct sock *child,
403 struct sk_buff *skb);
404extern void tcp_enter_frto(struct sock *sk);
405extern void tcp_enter_loss(struct sock *sk, int how);
406extern void tcp_clear_retrans(struct tcp_sock *tp);
407extern void tcp_update_metrics(struct sock *sk);
408
409extern void tcp_close(struct sock *sk,
410 long timeout);
1da177e4
LT		 411extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
412
413extern int tcp_getsockopt(struct sock *sk, int level,
414 int optname,
415 char __user *optval,
416 int __user *optlen);
417extern int tcp_setsockopt(struct sock *sk, int level,
418 int optname, char __user *optval,
419 int optlen);
420extern void tcp_set_keepalive(struct sock *sk, int val);
421extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
422 struct msghdr *msg,
423 size_t len, int nonblock,
424 int flags, int *addr_len);
425
1da177e4
LT		 426extern void tcp_parse_options(struct sk_buff *skb,
427 struct tcp_options_received *opt_rx,
428 int estab);
429
430/*
431 * TCP v4 functions exported for the inet6 API
432 */
433
1da177e4
LT		 434extern void tcp_v4_send_check(struct sock *sk,
435 struct tcphdr *th, int len,
436 struct sk_buff *skb);
437
438extern int tcp_v4_conn_request(struct sock *sk,
439 struct sk_buff *skb);
440
441extern struct sock * tcp_create_openreq_child(struct sock *sk,
60236fdd 442 struct request_sock *req,
1da177e4
LT		 443 struct sk_buff *skb);
444
445extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
446 struct sk_buff *skb,
60236fdd 447 struct request_sock *req,
1da177e4
LT		 448 struct dst_entry *dst);
449
450extern int tcp_v4_do_rcv(struct sock *sk,
451 struct sk_buff *skb);
452
453extern int tcp_v4_connect(struct sock *sk,
454 struct sockaddr *uaddr,
455 int addr_len);
456
457extern int tcp_connect(struct sock *sk);
458
459extern struct sk_buff * tcp_make_synack(struct sock *sk,
460 struct dst_entry *dst,
60236fdd 461 struct request_sock *req);
1da177e4
LT		 462
463extern int tcp_disconnect(struct sock *sk, int flags);
464
465extern void tcp_unhash(struct sock *sk);
466
467extern int tcp_v4_hash_connecting(struct sock *sk);
468
469
470/* From syncookies.c */
471extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
472 struct ip_options *opt);
473extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
474 __u16 *mss);
475
476/* tcp_output.c */
477
f6302d1d 478extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
a2e2a59c 479 unsigned int cur_mss, int nonagle);
f6302d1d 480extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp);
1da177e4
LT		 481extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
482extern void tcp_xmit_retransmit_queue(struct sock *);
483extern void tcp_simple_retransmit(struct sock *);
484extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
485
486extern void tcp_send_probe0(struct sock *);
487extern void tcp_send_partial(struct sock *);
488extern int tcp_write_wakeup(struct sock *);
489extern void tcp_send_fin(struct sock *sk);
86a76caf
VF		 490extern void tcp_send_active_reset(struct sock *sk,
491 unsigned int __nocast priority);
1da177e4 492extern int tcp_send_synack(struct sock *);
c1b4a7e6 493extern void tcp_push_one(struct sock *, unsigned int mss_now);
1da177e4
LT		 494extern void tcp_send_ack(struct sock *sk);
495extern void tcp_send_delayed_ack(struct sock *sk);
496
a762a980
DM		 497/* tcp_input.c */
498extern void tcp_cwnd_application_limited(struct sock *sk);
499
1da177e4
LT		 500/* tcp_timer.c */
501extern void tcp_init_xmit_timers(struct sock *);
463c84b9
ACM		 502static inline void tcp_clear_xmit_timers(struct sock *sk)
503{
504 inet_csk_clear_xmit_timers(sk);
505}
1da177e4 506
1da177e4
LT		 507extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
508extern unsigned int tcp_current_mss(struct sock *sk, int large);
509
1da177e4
LT		 510/* tcp_diag.c */
511extern void tcp_get_info(struct sock *, struct tcp_info *);
512
513/* Read 'sendfile()'-style from a TCP socket */
514typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
515 unsigned int, size_t);
516extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
517 sk_read_actor_t recv_actor);
518
1da177e4
LT		 519/* Initialize RCV_MSS value.
520 * RCV_MSS is an our guess about MSS used by the peer.
521 * We haven't any direct information about the MSS.
522 * It's better to underestimate the RCV_MSS rather than overestimate.
523 * Overestimations make us ACKing less frequently than needed.
524 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
525 */
526
527static inline void tcp_initialize_rcv_mss(struct sock *sk)
528{
529 struct tcp_sock *tp = tcp_sk(sk);
c1b4a7e6 530 unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache);
1da177e4
LT		 531
532 hint = min(hint, tp->rcv_wnd/2);
533 hint = min(hint, TCP_MIN_RCVMSS);
534 hint = max(hint, TCP_MIN_MSS);
535
463c84b9 536 inet_csk(sk)->icsk_ack.rcv_mss = hint;
1da177e4
LT		 537}
538
539static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
540{
541 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
542 ntohl(TCP_FLAG_ACK) |
543 snd_wnd);
544}
545
546static __inline__ void tcp_fast_path_on(struct tcp_sock *tp)
547{
548 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
549}
550
551static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp)
552{
b03efcfb 553 if (skb_queue_empty(&tp->out_of_order_queue) &&
1da177e4
LT		 554 tp->rcv_wnd &&
555 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
556 !tp->urg_data)
557 tcp_fast_path_on(tp);
558}
559
560/* Compute the actual receive window we are currently advertising.
561 * Rcv_nxt can be after the window if our peer push more data
562 * than the offered window.
563 */
564static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp)
565{
566 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
567
568 if (win < 0)
569 win = 0;
570 return (u32) win;
571}
572
573/* Choose a new window, without checks for shrinking, and without
574 * scaling applied to the result. The caller does these things
575 * if necessary. This is a "raw" window selection.
576 */
577extern u32 __tcp_select_window(struct sock *sk);
578
579/* TCP timestamps are only 32-bits, this causes a slight
580 * complication on 64-bit systems since we store a snapshot
581 * of jiffies in the buffer control blocks below. We decidely
582 * only use of the low 32-bits of jiffies and hide the ugly
583 * casts with the following macro.
584 */
585#define tcp_time_stamp ((__u32)(jiffies))
586
587/* This is what the send packet queueing engine uses to pass
588 * TCP per-packet control information to the transmission
589 * code. We also store the host-order sequence numbers in
590 * here too. This is 36 bytes on 32-bit architectures,
591 * 40 bytes on 64-bit machines, if this grows please adjust
592 * skbuff.h:skbuff->cb[xxx] size appropriately.
593 */
594struct tcp_skb_cb {
595 union {
596 struct inet_skb_parm h4;
597#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
598 struct inet6_skb_parm h6;
599#endif
600 } header; /* For incoming frames */
601 __u32 seq; /* Starting sequence number */
602 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
603 __u32 when; /* used to compute rtt's */
604 __u8 flags; /* TCP header flags. */
605
606 /* NOTE: These must match up to the flags byte in a
607 * real TCP header.
608 */
609#define TCPCB_FLAG_FIN 0x01
610#define TCPCB_FLAG_SYN 0x02
611#define TCPCB_FLAG_RST 0x04
612#define TCPCB_FLAG_PSH 0x08
613#define TCPCB_FLAG_ACK 0x10
614#define TCPCB_FLAG_URG 0x20
615#define TCPCB_FLAG_ECE 0x40
616#define TCPCB_FLAG_CWR 0x80
617
618 __u8 sacked; /* State flags for SACK/FACK. */
619#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
620#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
621#define TCPCB_LOST 0x04 /* SKB is lost */
622#define TCPCB_TAGBITS 0x07 /* All tag bits */
623
624#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
625#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
626
627#define TCPCB_URG 0x20 /* Urgent pointer advenced here */
628
629#define TCPCB_AT_TAIL (TCPCB_URG)
630
631 __u16 urg_ptr; /* Valid w/URG flags is set. */
632 __u32 ack_seq; /* Sequence number ACK'd */
633};
634
635#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
636
637#include <net/tcp_ecn.h>
638
639/* Due to TSO, an SKB can be composed of multiple actual
640 * packets. To keep these tracked properly, we use this.
641 */
642static inline int tcp_skb_pcount(const struct sk_buff *skb)
643{
644 return skb_shinfo(skb)->tso_segs;
645}
646
647/* This is valid iff tcp_skb_pcount() > 1. */
648static inline int tcp_skb_mss(const struct sk_buff *skb)
649{
650 return skb_shinfo(skb)->tso_size;
651}
652
653static inline void tcp_dec_pcount_approx(__u32 *count,
654 const struct sk_buff *skb)
655{
656 if (*count) {
657 *count -= tcp_skb_pcount(skb);
658 if ((int)*count < 0)
659 *count = 0;
660 }
661}
662
663static inline void tcp_packets_out_inc(struct sock *sk,
664 struct tcp_sock *tp,
665 const struct sk_buff *skb)
666{
667 int orig = tp->packets_out;
668
669 tp->packets_out += tcp_skb_pcount(skb);
670 if (!orig)
3f421baa
ACM		 671 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
672 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
1da177e4
LT		 673}
674
675static inline void tcp_packets_out_dec(struct tcp_sock *tp,
676 const struct sk_buff *skb)
677{
678 tp->packets_out -= tcp_skb_pcount(skb);
679}
680
317a76f9
SH		 681/* Events passed to congestion control interface */
682enum tcp_ca_event {
683 CA_EVENT_TX_START, /* first transmit when no packets in flight */
684 CA_EVENT_CWND_RESTART, /* congestion window restart */
685 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
686 CA_EVENT_FRTO, /* fast recovery timeout */
687 CA_EVENT_LOSS, /* loss timeout */
688 CA_EVENT_FAST_ACK, /* in sequence ack */
689 CA_EVENT_SLOW_ACK, /* other ack */
690};
691
692/*
693 * Interface for adding new TCP congestion control handlers
694 */
695#define TCP_CA_NAME_MAX 16
696struct tcp_congestion_ops {
697 struct list_head list;
698
699 /* initialize private data (optional) */
700 void (*init)(struct tcp_sock *tp);
701 /* cleanup private data (optional) */
702 void (*release)(struct tcp_sock *tp);
703
704 /* return slow start threshold (required) */
705 u32 (*ssthresh)(struct tcp_sock *tp);
706 /* lower bound for congestion window (optional) */
707 u32 (*min_cwnd)(struct tcp_sock *tp);
708 /* do new cwnd calculation (required) */
709 void (*cong_avoid)(struct tcp_sock *tp, u32 ack,
710 u32 rtt, u32 in_flight, int good_ack);
711 /* round trip time sample per acked packet (optional) */
712 void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt);
713 /* call before changing ca_state (optional) */
714 void (*set_state)(struct tcp_sock *tp, u8 new_state);
715 /* call when cwnd event occurs (optional) */
716 void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev);
717 /* new value of cwnd after loss (optional) */
718 u32 (*undo_cwnd)(struct tcp_sock *tp);
719 /* hook for packet ack accounting (optional) */
720 void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked);
721 /* get info for tcp_diag (optional) */
722 void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb);
723
724 char name[TCP_CA_NAME_MAX];
725 struct module *owner;
726};
727
728extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
729extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
730
731extern void tcp_init_congestion_control(struct tcp_sock *tp);
732extern void tcp_cleanup_congestion_control(struct tcp_sock *tp);
733extern int tcp_set_default_congestion_control(const char *name);
734extern void tcp_get_default_congestion_control(char *name);
5f8ef48d 735extern int tcp_set_congestion_control(struct tcp_sock *tp, const char *name);
317a76f9 736
5f8ef48d 737extern struct tcp_congestion_ops tcp_init_congestion_ops;
317a76f9
SH		 738extern u32 tcp_reno_ssthresh(struct tcp_sock *tp);
739extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack,
740 u32 rtt, u32 in_flight, int flag);
741extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp);
a8acfbac 742extern struct tcp_congestion_ops tcp_reno;
317a76f9
SH		 743
744static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state)
745{
746 if (tp->ca_ops->set_state)
747 tp->ca_ops->set_state(tp, ca_state);
748 tp->ca_state = ca_state;
749}
750
751static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event)
752{
753 if (tp->ca_ops->cwnd_event)
754 tp->ca_ops->cwnd_event(tp, event);
755}
756
1da177e4
LT		 757/* This determines how many packets are "in the network" to the best
758 * of our knowledge. In many cases it is conservative, but where
759 * detailed information is available from the receiver (via SACK
760 * blocks etc.) we can make more aggressive calculations.
761 *
762 * Use this for decisions involving congestion control, use just
763 * tp->packets_out to determine if the send queue is empty or not.
764 *
765 * Read this equation as:
766 *
767 * "Packets sent once on transmission queue" MINUS
768 * "Packets left network, but not honestly ACKed yet" PLUS
769 * "Packets fast retransmitted"
770 */
771static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
772{
773 return (tp->packets_out - tp->left_out + tp->retrans_out);
774}
775
1da177e4
LT		 776/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
777 * The exception is rate halving phase, when cwnd is decreasing towards
778 * ssthresh.
779 */
780static inline __u32 tcp_current_ssthresh(struct tcp_sock *tp)
781{
782 if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery))
783 return tp->snd_ssthresh;
784 else
785 return max(tp->snd_ssthresh,
786 ((tp->snd_cwnd >> 1) +
787 (tp->snd_cwnd >> 2)));
788}
789
790static inline void tcp_sync_left_out(struct tcp_sock *tp)
791{
792 if (tp->rx_opt.sack_ok &&
793 (tp->sacked_out >= tp->packets_out - tp->lost_out))
794 tp->sacked_out = tp->packets_out - tp->lost_out;
795 tp->left_out = tp->sacked_out + tp->lost_out;
796}
797
d1b04c08 798/* Set slow start threshold and cwnd not falling to slow start */
1da177e4
LT		 799static inline void __tcp_enter_cwr(struct tcp_sock *tp)
800{
801 tp->undo_marker = 0;
317a76f9 802 tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
1da177e4
LT		 803 tp->snd_cwnd = min(tp->snd_cwnd,
804 tcp_packets_in_flight(tp) + 1U);
805 tp->snd_cwnd_cnt = 0;
806 tp->high_seq = tp->snd_nxt;
807 tp->snd_cwnd_stamp = tcp_time_stamp;
808 TCP_ECN_queue_cwr(tp);
809}
810
811static inline void tcp_enter_cwr(struct tcp_sock *tp)
812{
813 tp->prior_ssthresh = 0;
814 if (tp->ca_state < TCP_CA_CWR) {
815 __tcp_enter_cwr(tp);
816 tcp_set_ca_state(tp, TCP_CA_CWR);
817 }
818}
819
820extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
821
822/* Slow start with delack produces 3 packets of burst, so that
823 * it is safe "de facto".
824 */
825static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
826{
827 return 3;
828}
829
1da177e4
LT		 830static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss,
831 const struct sk_buff *skb)
832{
833 if (skb->len < mss)
834 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
835}
836
1da177e4
LT		 837static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp)
838{
463c84b9
ACM		 839 const struct inet_connection_sock *icsk = inet_csk(sk);
840 if (!tp->packets_out && !icsk->icsk_pending)
3f421baa
ACM		 841 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
842 icsk->icsk_rto, TCP_RTO_MAX);
1da177e4
LT		 843}
844
1da177e4
LT		 845static __inline__ void tcp_push_pending_frames(struct sock *sk,
846 struct tcp_sock *tp)
847{
848 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle);
849}
850
1da177e4
LT		 851static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
852{
853 tp->snd_wl1 = seq;
854}
855
856static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
857{
858 tp->snd_wl1 = seq;
859}
860
1da177e4
LT		 861/*
862 * Calculate(/check) TCP checksum
863 */
864static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len,
865 unsigned long saddr, unsigned long daddr,
866 unsigned long base)
867{
868 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
869}
870
871static __inline__ int __tcp_checksum_complete(struct sk_buff *skb)
872{
873 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
874}
875
876static __inline__ int tcp_checksum_complete(struct sk_buff *skb)
877{
878 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
879 __tcp_checksum_complete(skb);
880}
881
882/* Prequeue for VJ style copy to user, combined with checksumming. */
883
884static __inline__ void tcp_prequeue_init(struct tcp_sock *tp)
885{
886 tp->ucopy.task = NULL;
887 tp->ucopy.len = 0;
888 tp->ucopy.memory = 0;
889 skb_queue_head_init(&tp->ucopy.prequeue);
890}
891
892/* Packet is added to VJ-style prequeue for processing in process
893 * context, if a reader task is waiting. Apparently, this exciting
894 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
895 * failed somewhere. Latency? Burstiness? Well, at least now we will
896 * see, why it failed. 8)8) --ANK
897 *
898 * NOTE: is this not too big to inline?
899 */
900static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
901{
902 struct tcp_sock *tp = tcp_sk(sk);
903
904 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
905 __skb_queue_tail(&tp->ucopy.prequeue, skb);
906 tp->ucopy.memory += skb->truesize;
907 if (tp->ucopy.memory > sk->sk_rcvbuf) {
908 struct sk_buff *skb1;
909
910 BUG_ON(sock_owned_by_user(sk));
911
912 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
913 sk->sk_backlog_rcv(sk, skb1);
914 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
915 }
916
917 tp->ucopy.memory = 0;
918 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
919 wake_up_interruptible(sk->sk_sleep);
463c84b9
ACM		 920 if (!inet_csk_ack_scheduled(sk))
921 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
3f421baa
ACM		 922 (3 * TCP_RTO_MIN) / 4,
923 TCP_RTO_MAX);
1da177e4
LT		 924 }
925 return 1;
926 }
927 return 0;
928}
929
930
931#undef STATE_TRACE
932
933#ifdef STATE_TRACE
934static const char *statename[]={
935 "Unused","Established","Syn Sent","Syn Recv",
936 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
937 "Close Wait","Last ACK","Listen","Closing"
938};
939#endif
940
941static __inline__ void tcp_set_state(struct sock *sk, int state)
942{
943 int oldstate = sk->sk_state;
944
945 switch (state) {
946 case TCP_ESTABLISHED:
947 if (oldstate != TCP_ESTABLISHED)
948 TCP_INC_STATS(TCP_MIB_CURRESTAB);
949 break;
950
951 case TCP_CLOSE:
952 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
953 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
954
955 sk->sk_prot->unhash(sk);
463c84b9 956 if (inet_csk(sk)->icsk_bind_hash &&
1da177e4 957 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2d8c4ce5 958 inet_put_port(&tcp_hashinfo, sk);
1da177e4
LT		 959 /* fall through */
960 default:
961 if (oldstate==TCP_ESTABLISHED)
962 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
963 }
964
965 /* Change state AFTER socket is unhashed to avoid closed
966 * socket sitting in hash tables.
967 */
968 sk->sk_state = state;
969
970#ifdef STATE_TRACE
971 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
972#endif
973}
974
975static __inline__ void tcp_done(struct sock *sk)
976{
977 tcp_set_state(sk, TCP_CLOSE);
978 tcp_clear_xmit_timers(sk);
979
980 sk->sk_shutdown = SHUTDOWN_MASK;
981
982 if (!sock_flag(sk, SOCK_DEAD))
983 sk->sk_state_change(sk);
984 else
0a5578cf 985 inet_csk_destroy_sock(sk);
1da177e4
LT		 986}
987
988static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt)
989{
990 rx_opt->dsack = 0;
991 rx_opt->eff_sacks = 0;
992 rx_opt->num_sacks = 0;
993}
994
995static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp)
996{
997 if (tp->rx_opt.tstamp_ok) {
998 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
999 (TCPOPT_NOP << 16) |
1000 (TCPOPT_TIMESTAMP << 8) |
1001 TCPOLEN_TIMESTAMP);
1002 *ptr++ = htonl(tstamp);
1003 *ptr++ = htonl(tp->rx_opt.ts_recent);
1004 }
1005 if (tp->rx_opt.eff_sacks) {
1006 struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks;
1007 int this_sack;
1008
1009 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
1010 (TCPOPT_NOP << 16) |
1011 (TCPOPT_SACK << 8) |
1012 (TCPOLEN_SACK_BASE +
1013 (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK)));
1014 for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) {
1015 *ptr++ = htonl(sp[this_sack].start_seq);
1016 *ptr++ = htonl(sp[this_sack].end_seq);
1017 }
1018 if (tp->rx_opt.dsack) {
1019 tp->rx_opt.dsack = 0;
1020 tp->rx_opt.eff_sacks--;
1021 }
1022 }
1023}
1024
1025/* Construct a tcp options header for a SYN or SYN_ACK packet.
1026 * If this is every changed make sure to change the definition of
1027 * MAX_SYN_SIZE to match the new maximum number of options that you
1028 * can generate.
1029 */
1030static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
1031 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent)
1032{
1033 /* We always get an MSS option.
1034 * The option bytes which will be seen in normal data
1035 * packets should timestamps be used, must be in the MSS
1036 * advertised. But we subtract them from tp->mss_cache so
1037 * that calculations in tcp_sendmsg are simpler etc.
1038 * So account for this fact here if necessary. If we
1039 * don't do this correctly, as a receiver we won't
1040 * recognize data packets as being full sized when we
1041 * should, and thus we won't abide by the delayed ACK
1042 * rules correctly.
1043 * SACKs don't matter, we never delay an ACK when we
1044 * have any of those going out.
1045 */
1046 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
1047 if (ts) {
1048 if(sack)
1049 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) |
1050 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1051 else
1052 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1053 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1054 *ptr++ = htonl(tstamp); /* TSVAL */
1055 *ptr++ = htonl(ts_recent); /* TSECR */
1056 } else if(sack)
1057 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1058 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM);
1059 if (offer_wscale)
1060 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale));
1061}
1062
1063/* Determine a window scaling and initial window to offer. */
1064extern void tcp_select_initial_window(int __space, __u32 mss,
1065 __u32 *rcv_wnd, __u32 *window_clamp,
1066 int wscale_ok, __u8 *rcv_wscale);
1067
1068static inline int tcp_win_from_space(int space)
1069{
1070 return sysctl_tcp_adv_win_scale<=0 ?
1071 (space>>(-sysctl_tcp_adv_win_scale)) :
1072 space - (space>>sysctl_tcp_adv_win_scale);
1073}
1074
1075/* Note: caller must be prepared to deal with negative returns */
1076static inline int tcp_space(const struct sock *sk)
1077{
1078 return tcp_win_from_space(sk->sk_rcvbuf -
1079 atomic_read(&sk->sk_rmem_alloc));
1080}
1081
1082static inline int tcp_full_space(const struct sock *sk)
1083{
1084 return tcp_win_from_space(sk->sk_rcvbuf);
1085}
1086
60236fdd 1087static __inline__ void tcp_openreq_init(struct request_sock *req,
1da177e4
LT		 1088 struct tcp_options_received *rx_opt,
1089 struct sk_buff *skb)
1090{
2e6599cb
ACM		 1091 struct inet_request_sock *ireq = inet_rsk(req);
1092
1da177e4 1093 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
2e6599cb 1094 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1da177e4
LT		 1095 req->mss = rx_opt->mss_clamp;
1096 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
2e6599cb
ACM		 1097 ireq->tstamp_ok = rx_opt->tstamp_ok;
1098 ireq->sack_ok = rx_opt->sack_ok;
1099 ireq->snd_wscale = rx_opt->snd_wscale;
1100 ireq->wscale_ok = rx_opt->wscale_ok;
1101 ireq->acked = 0;
1102 ireq->ecn_ok = 0;
1103 ireq->rmt_port = skb->h.th->source;
1da177e4
LT		 1104}
1105
1106extern void tcp_enter_memory_pressure(void);
1107
1da177e4
LT		 1108static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1109{
1110 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1111}
1112
1113static inline int keepalive_time_when(const struct tcp_sock *tp)
1114{
1115 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1116}
1117
463c84b9 1118static inline int tcp_fin_time(const struct sock *sk)
1da177e4 1119{
463c84b9
ACM		 1120 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1121 const int rto = inet_csk(sk)->icsk_rto;
1da177e4 1122
463c84b9
ACM		 1123 if (fin_timeout < (rto << 2) - (rto >> 1))
1124 fin_timeout = (rto << 2) - (rto >> 1);
1da177e4
LT		 1125
1126 return fin_timeout;
1127}
1128
1129static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1130{
1131 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1132 return 0;
1133 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1134 return 0;
1135
1136 /* RST segments are not recommended to carry timestamp,
1137 and, if they do, it is recommended to ignore PAWS because
1138 "their cleanup function should take precedence over timestamps."
1139 Certainly, it is mistake. It is necessary to understand the reasons
1140 of this constraint to relax it: if peer reboots, clock may go
1141 out-of-sync and half-open connections will not be reset.
1142 Actually, the problem would be not existing if all
1143 the implementations followed draft about maintaining clock
1144 via reboots. Linux-2.2 DOES NOT!
1145
1146 However, we can relax time bounds for RST segments to MSL.
1147 */
1148 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1149 return 0;
1150 return 1;
1151}
1152
1da177e4
LT		 1153#define TCP_CHECK_TIMER(sk) do { } while (0)
1154
1155static inline int tcp_use_frto(const struct sock *sk)
1156{
1157 const struct tcp_sock *tp = tcp_sk(sk);
1158
1159 /* F-RTO must be activated in sysctl and there must be some
1160 * unsent new data, and the advertised window should allow
1161 * sending it.
1162 */
1163 return (sysctl_tcp_frto && sk->sk_send_head &&
1164 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq,
1165 tp->snd_una + tp->snd_wnd));
1166}
1167
1168static inline void tcp_mib_init(void)
1169{
1170 /* See RFC 2012 */
1171 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1172 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1173 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1174 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1175}
1176
1177/* /proc */
1178enum tcp_seq_states {
1179 TCP_SEQ_STATE_LISTENING,
1180 TCP_SEQ_STATE_OPENREQ,
1181 TCP_SEQ_STATE_ESTABLISHED,
1182 TCP_SEQ_STATE_TIME_WAIT,
1183};
1184
1185struct tcp_seq_afinfo {
1186 struct module *owner;
1187 char *name;
1188 sa_family_t family;
1189 int (*seq_show) (struct seq_file *m, void *v);
1190 struct file_operations *seq_fops;
1191};
1192
1193struct tcp_iter_state {
1194 sa_family_t family;
1195 enum tcp_seq_states state;
1196 struct sock *syn_wait_sk;
1197 int bucket, sbucket, num, uid;
1198 struct seq_operations seq_ops;
1199};
1200
1201extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1202extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1203
1da177e4 1204#endif /* _TCP_H */
kernel source for telekom puls (alcatel/mediatek)