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[BNX2]: simplify parameter checks in bnx2_{get,set}_eeprom
[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>
295ff7ed 32#include <net/inet_timewait_sock.h>
77d8bf9c 33#include <net/inet_hashtables.h>
1da177e4 34#include <net/checksum.h>
2e6599cb 35#include <net/request_sock.h>
1da177e4
LT		 36#include <net/sock.h>
37#include <net/snmp.h>
38#include <net/ip.h>
c752f073
ACM		 39#include <net/tcp_states.h>
40
1da177e4
LT		 41#include <linux/seq_file.h>
42
6e04e021 43extern struct inet_hashinfo tcp_hashinfo;
1da177e4 44
1da177e4 45extern atomic_t tcp_orphan_count;
1da177e4 46extern void tcp_time_wait(struct sock *sk, int state, int timeo);
1da177e4 47
1da177e4
LT		 48#define MAX_TCP_HEADER (128 + MAX_HEADER)
49
50/*
51 * Never offer a window over 32767 without using window scaling. Some
52 * poor stacks do signed 16bit maths!
53 */
54#define MAX_TCP_WINDOW 32767U
55
56/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
57#define TCP_MIN_MSS 88U
58
59/* Minimal RCV_MSS. */
60#define TCP_MIN_RCVMSS 536U
61
62/* After receiving this amount of duplicate ACKs fast retransmit starts. */
63#define TCP_FASTRETRANS_THRESH 3
64
65/* Maximal reordering. */
66#define TCP_MAX_REORDERING 127
67
68/* Maximal number of ACKs sent quickly to accelerate slow-start. */
69#define TCP_MAX_QUICKACKS 16U
70
71/* urg_data states */
72#define TCP_URG_VALID 0x0100
73#define TCP_URG_NOTYET 0x0200
74#define TCP_URG_READ 0x0400
75
76#define TCP_RETR1 3 /*
77 * This is how many retries it does before it
78 * tries to figure out if the gateway is
79 * down. Minimal RFC value is 3; it corresponds
80 * to ~3sec-8min depending on RTO.
81 */
82
83#define TCP_RETR2 15 /*
84 * This should take at least
85 * 90 minutes to time out.
86 * RFC1122 says that the limit is 100 sec.
87 * 15 is ~13-30min depending on RTO.
88 */
89
90#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
91 * connection: ~180sec is RFC minumum */
92
93#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
94 * connection: ~180sec is RFC minumum */
95
96
97#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
98 * socket. 7 is ~50sec-16min.
99 */
100
101
102#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
103 * state, about 60 seconds */
104#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
105 /* BSD style FIN_WAIT2 deadlock breaker.
106 * It used to be 3min, new value is 60sec,
107 * to combine FIN-WAIT-2 timeout with
108 * TIME-WAIT timer.
109 */
110
111#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
112#if HZ >= 100
113#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
114#define TCP_ATO_MIN ((unsigned)(HZ/25))
115#else
116#define TCP_DELACK_MIN 4U
117#define TCP_ATO_MIN 4U
118#endif
119#define TCP_RTO_MAX ((unsigned)(120*HZ))
120#define TCP_RTO_MIN ((unsigned)(HZ/5))
121#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
122
123#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
124 * for local resources.
125 */
126
127#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
128#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
129#define TCP_KEEPALIVE_INTVL (75*HZ)
130
131#define MAX_TCP_KEEPIDLE 32767
132#define MAX_TCP_KEEPINTVL 32767
133#define MAX_TCP_KEEPCNT 127
134#define MAX_TCP_SYNCNT 127
135
136#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
137#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
138
139#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
140#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
141 * after this time. It should be equal
142 * (or greater than) TCP_TIMEWAIT_LEN
143 * to provide reliability equal to one
144 * provided by timewait state.
145 */
146#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
147 * timestamps. It must be less than
148 * minimal timewait lifetime.
149 */
1da177e4
LT		 150/*
151 * TCP option
152 */
153
154#define TCPOPT_NOP 1 /* Padding */
155#define TCPOPT_EOL 0 /* End of options */
156#define TCPOPT_MSS 2 /* Segment size negotiating */
157#define TCPOPT_WINDOW 3 /* Window scaling */
158#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
159#define TCPOPT_SACK 5 /* SACK Block */
160#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
161
162/*
163 * TCP option lengths
164 */
165
166#define TCPOLEN_MSS 4
167#define TCPOLEN_WINDOW 3
168#define TCPOLEN_SACK_PERM 2
169#define TCPOLEN_TIMESTAMP 10
170
171/* But this is what stacks really send out. */
172#define TCPOLEN_TSTAMP_ALIGNED 12
173#define TCPOLEN_WSCALE_ALIGNED 4
174#define TCPOLEN_SACKPERM_ALIGNED 4
175#define TCPOLEN_SACK_BASE 2
176#define TCPOLEN_SACK_BASE_ALIGNED 4
177#define TCPOLEN_SACK_PERBLOCK 8
178
1da177e4
LT		 179/* Flags in tp->nonagle */
180#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
181#define TCP_NAGLE_CORK 2 /* Socket is corked */
182#define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */
183
295ff7ed
ACM		 184extern struct inet_timewait_death_row tcp_death_row;
185
1da177e4 186/* sysctl variables for tcp */
1da177e4
LT		 187extern int sysctl_tcp_timestamps;
188extern int sysctl_tcp_window_scaling;
189extern int sysctl_tcp_sack;
190extern int sysctl_tcp_fin_timeout;
1da177e4
LT		 191extern int sysctl_tcp_keepalive_time;
192extern int sysctl_tcp_keepalive_probes;
193extern int sysctl_tcp_keepalive_intvl;
194extern int sysctl_tcp_syn_retries;
195extern int sysctl_tcp_synack_retries;
196extern int sysctl_tcp_retries1;
197extern int sysctl_tcp_retries2;
198extern int sysctl_tcp_orphan_retries;
199extern int sysctl_tcp_syncookies;
200extern int sysctl_tcp_retrans_collapse;
201extern int sysctl_tcp_stdurg;
202extern int sysctl_tcp_rfc1337;
203extern int sysctl_tcp_abort_on_overflow;
204extern int sysctl_tcp_max_orphans;
1da177e4
LT		 205extern int sysctl_tcp_fack;
206extern int sysctl_tcp_reordering;
207extern int sysctl_tcp_ecn;
208extern int sysctl_tcp_dsack;
209extern int sysctl_tcp_mem[3];
210extern int sysctl_tcp_wmem[3];
211extern int sysctl_tcp_rmem[3];
212extern int sysctl_tcp_app_win;
213extern int sysctl_tcp_adv_win_scale;
214extern int sysctl_tcp_tw_reuse;
215extern int sysctl_tcp_frto;
216extern int sysctl_tcp_low_latency;
1da177e4 217extern int sysctl_tcp_nometrics_save;
1da177e4
LT		 218extern int sysctl_tcp_moderate_rcvbuf;
219extern int sysctl_tcp_tso_win_divisor;
220
221extern atomic_t tcp_memory_allocated;
222extern atomic_t tcp_sockets_allocated;
223extern int tcp_memory_pressure;
224
1da177e4
LT		 225/*
226 * Pointers to address related TCP functions
227 * (i.e. things that depend on the address family)
228 */
229
230struct tcp_func {
231 int (*queue_xmit) (struct sk_buff *skb,
232 int ipfragok);
233
234 void (*send_check) (struct sock *sk,
235 struct tcphdr *th,
236 int len,
237 struct sk_buff *skb);
238
239 int (*rebuild_header) (struct sock *sk);
240
241 int (*conn_request) (struct sock *sk,
242 struct sk_buff *skb);
243
244 struct sock * (*syn_recv_sock) (struct sock *sk,
245 struct sk_buff *skb,
60236fdd 246 struct request_sock *req,
1da177e4
LT		 247 struct dst_entry *dst);
248
249 int (*remember_stamp) (struct sock *sk);
250
251 __u16 net_header_len;
252
253 int (*setsockopt) (struct sock *sk,
254 int level,
255 int optname,
256 char __user *optval,
257 int optlen);
258
259 int (*getsockopt) (struct sock *sk,
260 int level,
261 int optname,
262 char __user *optval,
263 int __user *optlen);
264
265
266 void (*addr2sockaddr) (struct sock *sk,
267 struct sockaddr *);
268
269 int sockaddr_len;
270};
271
272/*
273 * The next routines deal with comparing 32 bit unsigned ints
274 * and worry about wraparound (automatic with unsigned arithmetic).
275 */
276
277static inline int before(__u32 seq1, __u32 seq2)
278{
279 return (__s32)(seq1-seq2) < 0;
280}
281
282static inline int after(__u32 seq1, __u32 seq2)
283{
284 return (__s32)(seq2-seq1) < 0;
285}
286
287
288/* is s2<=s1<=s3 ? */
289static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
290{
291 return seq3 - seq2 >= seq1 - seq2;
292}
293
294
295extern struct proto tcp_prot;
296
297DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
298#define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
299#define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
300#define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
301#define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
302#define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
303#define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
304
1da177e4
LT		 305extern void tcp_v4_err(struct sk_buff *skb, u32);
306
307extern void tcp_shutdown (struct sock *sk, int how);
308
309extern int tcp_v4_rcv(struct sk_buff *skb);
310
311extern int tcp_v4_remember_stamp(struct sock *sk);
312
8feaf0c0 313extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
1da177e4
LT		 314
315extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
316 struct msghdr *msg, size_t size);
317extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
318
319extern int tcp_ioctl(struct sock *sk,
320 int cmd,
321 unsigned long arg);
322
323extern int tcp_rcv_state_process(struct sock *sk,
324 struct sk_buff *skb,
325 struct tcphdr *th,
326 unsigned len);
327
328extern int tcp_rcv_established(struct sock *sk,
329 struct sk_buff *skb,
330 struct tcphdr *th,
331 unsigned len);
332
333extern void tcp_rcv_space_adjust(struct sock *sk);
334
463c84b9
ACM		 335static inline void tcp_dec_quickack_mode(struct sock *sk,
336 const unsigned int pkts)
1da177e4 337{
463c84b9 338 struct inet_connection_sock *icsk = inet_csk(sk);
fc6415bc 339
463c84b9
ACM		 340 if (icsk->icsk_ack.quick) {
341 if (pkts >= icsk->icsk_ack.quick) {
342 icsk->icsk_ack.quick = 0;
fc6415bc 343 /* Leaving quickack mode we deflate ATO. */
463c84b9 344 icsk->icsk_ack.ato = TCP_ATO_MIN;
fc6415bc 345 } else
463c84b9 346 icsk->icsk_ack.quick -= pkts;
1da177e4
LT		 347 }
348}
349
463c84b9 350extern void tcp_enter_quickack_mode(struct sock *sk);
1da177e4 351
1da177e4
LT		 352static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
353{
354 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
355}
356
357enum tcp_tw_status
358{
359 TCP_TW_SUCCESS = 0,
360 TCP_TW_RST = 1,
361 TCP_TW_ACK = 2,
362 TCP_TW_SYN = 3
363};
364
365
8feaf0c0 366extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
1da177e4 367 struct sk_buff *skb,
8feaf0c0 368 const struct tcphdr *th);
1da177e4
LT		 369
370extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
60236fdd
ACM		 371 struct request_sock *req,
372 struct request_sock **prev);
1da177e4
LT		 373extern int tcp_child_process(struct sock *parent,
374 struct sock *child,
375 struct sk_buff *skb);
376extern void tcp_enter_frto(struct sock *sk);
377extern void tcp_enter_loss(struct sock *sk, int how);
378extern void tcp_clear_retrans(struct tcp_sock *tp);
379extern void tcp_update_metrics(struct sock *sk);
380
381extern void tcp_close(struct sock *sk,
382 long timeout);
1da177e4
LT		 383extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
384
385extern int tcp_getsockopt(struct sock *sk, int level,
386 int optname,
387 char __user *optval,
388 int __user *optlen);
389extern int tcp_setsockopt(struct sock *sk, int level,
390 int optname, char __user *optval,
391 int optlen);
392extern void tcp_set_keepalive(struct sock *sk, int val);
393extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
394 struct msghdr *msg,
395 size_t len, int nonblock,
396 int flags, int *addr_len);
397
1da177e4
LT		 398extern void tcp_parse_options(struct sk_buff *skb,
399 struct tcp_options_received *opt_rx,
400 int estab);
401
402/*
403 * TCP v4 functions exported for the inet6 API
404 */
405
1da177e4
LT		 406extern void tcp_v4_send_check(struct sock *sk,
407 struct tcphdr *th, int len,
408 struct sk_buff *skb);
409
410extern int tcp_v4_conn_request(struct sock *sk,
411 struct sk_buff *skb);
412
413extern struct sock * tcp_create_openreq_child(struct sock *sk,
60236fdd 414 struct request_sock *req,
1da177e4
LT		 415 struct sk_buff *skb);
416
417extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
418 struct sk_buff *skb,
60236fdd 419 struct request_sock *req,
1da177e4
LT		 420 struct dst_entry *dst);
421
422extern int tcp_v4_do_rcv(struct sock *sk,
423 struct sk_buff *skb);
424
425extern int tcp_v4_connect(struct sock *sk,
426 struct sockaddr *uaddr,
427 int addr_len);
428
429extern int tcp_connect(struct sock *sk);
430
431extern struct sk_buff * tcp_make_synack(struct sock *sk,
432 struct dst_entry *dst,
60236fdd 433 struct request_sock *req);
1da177e4
LT		 434
435extern int tcp_disconnect(struct sock *sk, int flags);
436
437extern void tcp_unhash(struct sock *sk);
438
439extern int tcp_v4_hash_connecting(struct sock *sk);
440
441
442/* From syncookies.c */
443extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
444 struct ip_options *opt);
445extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
446 __u16 *mss);
447
448/* tcp_output.c */
449
f6302d1d 450extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
a2e2a59c 451 unsigned int cur_mss, int nonagle);
f6302d1d 452extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp);
1da177e4
LT		 453extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
454extern void tcp_xmit_retransmit_queue(struct sock *);
455extern void tcp_simple_retransmit(struct sock *);
456extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
6475be16 457extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
1da177e4
LT		 458
459extern void tcp_send_probe0(struct sock *);
460extern void tcp_send_partial(struct sock *);
461extern int tcp_write_wakeup(struct sock *);
462extern void tcp_send_fin(struct sock *sk);
dd0fc66f 463extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
1da177e4 464extern int tcp_send_synack(struct sock *);
c1b4a7e6 465extern void tcp_push_one(struct sock *, unsigned int mss_now);
1da177e4
LT		 466extern void tcp_send_ack(struct sock *sk);
467extern void tcp_send_delayed_ack(struct sock *sk);
468
a762a980
DM		 469/* tcp_input.c */
470extern void tcp_cwnd_application_limited(struct sock *sk);
471
1da177e4
LT		 472/* tcp_timer.c */
473extern void tcp_init_xmit_timers(struct sock *);
463c84b9
ACM		 474static inline void tcp_clear_xmit_timers(struct sock *sk)
475{
476 inet_csk_clear_xmit_timers(sk);
477}
1da177e4 478
1da177e4
LT		 479extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
480extern unsigned int tcp_current_mss(struct sock *sk, int large);
481
17b085ea 482/* tcp.c */
1da177e4
LT		 483extern void tcp_get_info(struct sock *, struct tcp_info *);
484
485/* Read 'sendfile()'-style from a TCP socket */
486typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
487 unsigned int, size_t);
488extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
489 sk_read_actor_t recv_actor);
490
1da177e4
LT		 491/* Initialize RCV_MSS value.
492 * RCV_MSS is an our guess about MSS used by the peer.
493 * We haven't any direct information about the MSS.
494 * It's better to underestimate the RCV_MSS rather than overestimate.
495 * Overestimations make us ACKing less frequently than needed.
496 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
497 */
498
499static inline void tcp_initialize_rcv_mss(struct sock *sk)
500{
501 struct tcp_sock *tp = tcp_sk(sk);
c1b4a7e6 502 unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache);
1da177e4
LT		 503
504 hint = min(hint, tp->rcv_wnd/2);
505 hint = min(hint, TCP_MIN_RCVMSS);
506 hint = max(hint, TCP_MIN_MSS);
507
463c84b9 508 inet_csk(sk)->icsk_ack.rcv_mss = hint;
1da177e4
LT		 509}
510
511static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
512{
513 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
514 ntohl(TCP_FLAG_ACK) |
515 snd_wnd);
516}
517
518static __inline__ void tcp_fast_path_on(struct tcp_sock *tp)
519{
520 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
521}
522
523static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp)
524{
b03efcfb 525 if (skb_queue_empty(&tp->out_of_order_queue) &&
1da177e4
LT		 526 tp->rcv_wnd &&
527 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
528 !tp->urg_data)
529 tcp_fast_path_on(tp);
530}
531
532/* Compute the actual receive window we are currently advertising.
533 * Rcv_nxt can be after the window if our peer push more data
534 * than the offered window.
535 */
536static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp)
537{
538 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
539
540 if (win < 0)
541 win = 0;
542 return (u32) win;
543}
544
545/* Choose a new window, without checks for shrinking, and without
546 * scaling applied to the result. The caller does these things
547 * if necessary. This is a "raw" window selection.
548 */
549extern u32 __tcp_select_window(struct sock *sk);
550
551/* TCP timestamps are only 32-bits, this causes a slight
552 * complication on 64-bit systems since we store a snapshot
553 * of jiffies in the buffer control blocks below. We decidely
554 * only use of the low 32-bits of jiffies and hide the ugly
555 * casts with the following macro.
556 */
557#define tcp_time_stamp ((__u32)(jiffies))
558
559/* This is what the send packet queueing engine uses to pass
560 * TCP per-packet control information to the transmission
561 * code. We also store the host-order sequence numbers in
562 * here too. This is 36 bytes on 32-bit architectures,
563 * 40 bytes on 64-bit machines, if this grows please adjust
564 * skbuff.h:skbuff->cb[xxx] size appropriately.
565 */
566struct tcp_skb_cb {
567 union {
568 struct inet_skb_parm h4;
569#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
570 struct inet6_skb_parm h6;
571#endif
572 } header; /* For incoming frames */
573 __u32 seq; /* Starting sequence number */
574 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
575 __u32 when; /* used to compute rtt's */
576 __u8 flags; /* TCP header flags. */
577
578 /* NOTE: These must match up to the flags byte in a
579 * real TCP header.
580 */
581#define TCPCB_FLAG_FIN 0x01
582#define TCPCB_FLAG_SYN 0x02
583#define TCPCB_FLAG_RST 0x04
584#define TCPCB_FLAG_PSH 0x08
585#define TCPCB_FLAG_ACK 0x10
586#define TCPCB_FLAG_URG 0x20
587#define TCPCB_FLAG_ECE 0x40
588#define TCPCB_FLAG_CWR 0x80
589
590 __u8 sacked; /* State flags for SACK/FACK. */
591#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
592#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
593#define TCPCB_LOST 0x04 /* SKB is lost */
594#define TCPCB_TAGBITS 0x07 /* All tag bits */
595
596#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
597#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
598
599#define TCPCB_URG 0x20 /* Urgent pointer advenced here */
600
601#define TCPCB_AT_TAIL (TCPCB_URG)
602
603 __u16 urg_ptr; /* Valid w/URG flags is set. */
604 __u32 ack_seq; /* Sequence number ACK'd */
605};
606
607#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
608
609#include <net/tcp_ecn.h>
610
611/* Due to TSO, an SKB can be composed of multiple actual
612 * packets. To keep these tracked properly, we use this.
613 */
614static inline int tcp_skb_pcount(const struct sk_buff *skb)
615{
616 return skb_shinfo(skb)->tso_segs;
617}
618
619/* This is valid iff tcp_skb_pcount() > 1. */
620static inline int tcp_skb_mss(const struct sk_buff *skb)
621{
622 return skb_shinfo(skb)->tso_size;
623}
624
625static inline void tcp_dec_pcount_approx(__u32 *count,
626 const struct sk_buff *skb)
627{
628 if (*count) {
629 *count -= tcp_skb_pcount(skb);
630 if ((int)*count < 0)
631 *count = 0;
632 }
633}
634
635static inline void tcp_packets_out_inc(struct sock *sk,
636 struct tcp_sock *tp,
637 const struct sk_buff *skb)
638{
639 int orig = tp->packets_out;
640
641 tp->packets_out += tcp_skb_pcount(skb);
642 if (!orig)
3f421baa
ACM		 643 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
644 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
1da177e4
LT		 645}
646
647static inline void tcp_packets_out_dec(struct tcp_sock *tp,
648 const struct sk_buff *skb)
649{
650 tp->packets_out -= tcp_skb_pcount(skb);
651}
652
317a76f9
SH		 653/* Events passed to congestion control interface */
654enum tcp_ca_event {
655 CA_EVENT_TX_START, /* first transmit when no packets in flight */
656 CA_EVENT_CWND_RESTART, /* congestion window restart */
657 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
658 CA_EVENT_FRTO, /* fast recovery timeout */
659 CA_EVENT_LOSS, /* loss timeout */
660 CA_EVENT_FAST_ACK, /* in sequence ack */
661 CA_EVENT_SLOW_ACK, /* other ack */
662};
663
664/*
665 * Interface for adding new TCP congestion control handlers
666 */
667#define TCP_CA_NAME_MAX 16
668struct tcp_congestion_ops {
669 struct list_head list;
670
671 /* initialize private data (optional) */
6687e988 672 void (*init)(struct sock *sk);
317a76f9 673 /* cleanup private data (optional) */
6687e988 674 void (*release)(struct sock *sk);
317a76f9
SH		 675
676 /* return slow start threshold (required) */
6687e988 677 u32 (*ssthresh)(struct sock *sk);
317a76f9 678 /* lower bound for congestion window (optional) */
6687e988 679 u32 (*min_cwnd)(struct sock *sk);
317a76f9 680 /* do new cwnd calculation (required) */
6687e988 681 void (*cong_avoid)(struct sock *sk, u32 ack,
317a76f9
SH		 682 u32 rtt, u32 in_flight, int good_ack);
683 /* round trip time sample per acked packet (optional) */
6687e988 684 void (*rtt_sample)(struct sock *sk, u32 usrtt);
317a76f9 685 /* call before changing ca_state (optional) */
6687e988 686 void (*set_state)(struct sock *sk, u8 new_state);
317a76f9 687 /* call when cwnd event occurs (optional) */
6687e988 688 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
317a76f9 689 /* new value of cwnd after loss (optional) */
6687e988 690 u32 (*undo_cwnd)(struct sock *sk);
317a76f9 691 /* hook for packet ack accounting (optional) */
6687e988 692 void (*pkts_acked)(struct sock *sk, u32 num_acked);
73c1f4a0 693 /* get info for inet_diag (optional) */
6687e988 694 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
317a76f9
SH		 695
696 char name[TCP_CA_NAME_MAX];
697 struct module *owner;
698};
699
700extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
701extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
702
6687e988
ACM		 703extern void tcp_init_congestion_control(struct sock *sk);
704extern void tcp_cleanup_congestion_control(struct sock *sk);
317a76f9
SH		 705extern int tcp_set_default_congestion_control(const char *name);
706extern void tcp_get_default_congestion_control(char *name);
6687e988 707extern int tcp_set_congestion_control(struct sock *sk, const char *name);
317a76f9 708
5f8ef48d 709extern struct tcp_congestion_ops tcp_init_congestion_ops;
6687e988
ACM		 710extern u32 tcp_reno_ssthresh(struct sock *sk);
711extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack,
317a76f9 712 u32 rtt, u32 in_flight, int flag);
6687e988 713extern u32 tcp_reno_min_cwnd(struct sock *sk);
a8acfbac 714extern struct tcp_congestion_ops tcp_reno;
317a76f9 715
6687e988 716static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
317a76f9 717{
6687e988
ACM		 718 struct inet_connection_sock *icsk = inet_csk(sk);
719
720 if (icsk->icsk_ca_ops->set_state)
721 icsk->icsk_ca_ops->set_state(sk, ca_state);
722 icsk->icsk_ca_state = ca_state;
317a76f9
SH		 723}
724
6687e988 725static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
317a76f9 726{
6687e988
ACM		 727 const struct inet_connection_sock *icsk = inet_csk(sk);
728
729 if (icsk->icsk_ca_ops->cwnd_event)
730 icsk->icsk_ca_ops->cwnd_event(sk, event);
317a76f9
SH		 731}
732
1da177e4
LT		 733/* This determines how many packets are "in the network" to the best
734 * of our knowledge. In many cases it is conservative, but where
735 * detailed information is available from the receiver (via SACK
736 * blocks etc.) we can make more aggressive calculations.
737 *
738 * Use this for decisions involving congestion control, use just
739 * tp->packets_out to determine if the send queue is empty or not.
740 *
741 * Read this equation as:
742 *
743 * "Packets sent once on transmission queue" MINUS
744 * "Packets left network, but not honestly ACKed yet" PLUS
745 * "Packets fast retransmitted"
746 */
747static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
748{
749 return (tp->packets_out - tp->left_out + tp->retrans_out);
750}
751
1da177e4
LT		 752/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
753 * The exception is rate halving phase, when cwnd is decreasing towards
754 * ssthresh.
755 */
6687e988 756static inline __u32 tcp_current_ssthresh(const struct sock *sk)
1da177e4 757{
6687e988
ACM		 758 const struct tcp_sock *tp = tcp_sk(sk);
759 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
1da177e4
LT		 760 return tp->snd_ssthresh;
761 else
762 return max(tp->snd_ssthresh,
763 ((tp->snd_cwnd >> 1) +
764 (tp->snd_cwnd >> 2)));
765}
766
767static inline void tcp_sync_left_out(struct tcp_sock *tp)
768{
769 if (tp->rx_opt.sack_ok &&
770 (tp->sacked_out >= tp->packets_out - tp->lost_out))
771 tp->sacked_out = tp->packets_out - tp->lost_out;
772 tp->left_out = tp->sacked_out + tp->lost_out;
773}
774
d1b04c08 775/* Set slow start threshold and cwnd not falling to slow start */
6687e988 776static inline void __tcp_enter_cwr(struct sock *sk)
1da177e4 777{
6687e988
ACM		 778 const struct inet_connection_sock *icsk = inet_csk(sk);
779 struct tcp_sock *tp = tcp_sk(sk);
780
1da177e4 781 tp->undo_marker = 0;
6687e988 782 tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
1da177e4
LT		 783 tp->snd_cwnd = min(tp->snd_cwnd,
784 tcp_packets_in_flight(tp) + 1U);
785 tp->snd_cwnd_cnt = 0;
786 tp->high_seq = tp->snd_nxt;
787 tp->snd_cwnd_stamp = tcp_time_stamp;
788 TCP_ECN_queue_cwr(tp);
789}
790
6687e988 791static inline void tcp_enter_cwr(struct sock *sk)
1da177e4 792{
6687e988
ACM		 793 struct tcp_sock *tp = tcp_sk(sk);
794
1da177e4 795 tp->prior_ssthresh = 0;
6687e988
ACM		 796 if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) {
797 __tcp_enter_cwr(sk);
798 tcp_set_ca_state(sk, TCP_CA_CWR);
1da177e4
LT		 799 }
800}
801
802extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
803
804/* Slow start with delack produces 3 packets of burst, so that
805 * it is safe "de facto".
806 */
807static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
808{
809 return 3;
810}
811
1da177e4
LT		 812static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss,
813 const struct sk_buff *skb)
814{
815 if (skb->len < mss)
816 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
817}
818
1da177e4
LT		 819static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp)
820{
463c84b9
ACM		 821 const struct inet_connection_sock *icsk = inet_csk(sk);
822 if (!tp->packets_out && !icsk->icsk_pending)
3f421baa
ACM		 823 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
824 icsk->icsk_rto, TCP_RTO_MAX);
1da177e4
LT		 825}
826
1da177e4
LT		 827static __inline__ void tcp_push_pending_frames(struct sock *sk,
828 struct tcp_sock *tp)
829{
830 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle);
831}
832
1da177e4
LT		 833static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
834{
835 tp->snd_wl1 = seq;
836}
837
838static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
839{
840 tp->snd_wl1 = seq;
841}
842
1da177e4
LT		 843/*
844 * Calculate(/check) TCP checksum
845 */
846static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len,
847 unsigned long saddr, unsigned long daddr,
848 unsigned long base)
849{
850 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
851}
852
853static __inline__ int __tcp_checksum_complete(struct sk_buff *skb)
854{
855 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
856}
857
858static __inline__ int tcp_checksum_complete(struct sk_buff *skb)
859{
860 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
861 __tcp_checksum_complete(skb);
862}
863
864/* Prequeue for VJ style copy to user, combined with checksumming. */
865
866static __inline__ void tcp_prequeue_init(struct tcp_sock *tp)
867{
868 tp->ucopy.task = NULL;
869 tp->ucopy.len = 0;
870 tp->ucopy.memory = 0;
871 skb_queue_head_init(&tp->ucopy.prequeue);
872}
873
874/* Packet is added to VJ-style prequeue for processing in process
875 * context, if a reader task is waiting. Apparently, this exciting
876 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
877 * failed somewhere. Latency? Burstiness? Well, at least now we will
878 * see, why it failed. 8)8) --ANK
879 *
880 * NOTE: is this not too big to inline?
881 */
882static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
883{
884 struct tcp_sock *tp = tcp_sk(sk);
885
886 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
887 __skb_queue_tail(&tp->ucopy.prequeue, skb);
888 tp->ucopy.memory += skb->truesize;
889 if (tp->ucopy.memory > sk->sk_rcvbuf) {
890 struct sk_buff *skb1;
891
892 BUG_ON(sock_owned_by_user(sk));
893
894 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
895 sk->sk_backlog_rcv(sk, skb1);
896 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
897 }
898
899 tp->ucopy.memory = 0;
900 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
901 wake_up_interruptible(sk->sk_sleep);
463c84b9
ACM		 902 if (!inet_csk_ack_scheduled(sk))
903 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
3f421baa
ACM		 904 (3 * TCP_RTO_MIN) / 4,
905 TCP_RTO_MAX);
1da177e4
LT		 906 }
907 return 1;
908 }
909 return 0;
910}
911
912
913#undef STATE_TRACE
914
915#ifdef STATE_TRACE
916static const char *statename[]={
917 "Unused","Established","Syn Sent","Syn Recv",
918 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
919 "Close Wait","Last ACK","Listen","Closing"
920};
921#endif
922
923static __inline__ void tcp_set_state(struct sock *sk, int state)
924{
925 int oldstate = sk->sk_state;
926
927 switch (state) {
928 case TCP_ESTABLISHED:
929 if (oldstate != TCP_ESTABLISHED)
930 TCP_INC_STATS(TCP_MIB_CURRESTAB);
931 break;
932
933 case TCP_CLOSE:
934 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
935 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
936
937 sk->sk_prot->unhash(sk);
463c84b9 938 if (inet_csk(sk)->icsk_bind_hash &&
1da177e4 939 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2d8c4ce5 940 inet_put_port(&tcp_hashinfo, sk);
1da177e4
LT		 941 /* fall through */
942 default:
943 if (oldstate==TCP_ESTABLISHED)
944 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
945 }
946
947 /* Change state AFTER socket is unhashed to avoid closed
948 * socket sitting in hash tables.
949 */
950 sk->sk_state = state;
951
952#ifdef STATE_TRACE
953 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
954#endif
955}
956
957static __inline__ void tcp_done(struct sock *sk)
958{
959 tcp_set_state(sk, TCP_CLOSE);
960 tcp_clear_xmit_timers(sk);
961
962 sk->sk_shutdown = SHUTDOWN_MASK;
963
964 if (!sock_flag(sk, SOCK_DEAD))
965 sk->sk_state_change(sk);
966 else
0a5578cf 967 inet_csk_destroy_sock(sk);
1da177e4
LT		 968}
969
970static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt)
971{
972 rx_opt->dsack = 0;
973 rx_opt->eff_sacks = 0;
974 rx_opt->num_sacks = 0;
975}
976
977static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp)
978{
979 if (tp->rx_opt.tstamp_ok) {
980 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
981 (TCPOPT_NOP << 16) |
982 (TCPOPT_TIMESTAMP << 8) |
983 TCPOLEN_TIMESTAMP);
984 *ptr++ = htonl(tstamp);
985 *ptr++ = htonl(tp->rx_opt.ts_recent);
986 }
987 if (tp->rx_opt.eff_sacks) {
988 struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks;
989 int this_sack;
990
991 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
992 (TCPOPT_NOP << 16) |
993 (TCPOPT_SACK << 8) |
994 (TCPOLEN_SACK_BASE +
995 (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK)));
996 for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) {
997 *ptr++ = htonl(sp[this_sack].start_seq);
998 *ptr++ = htonl(sp[this_sack].end_seq);
999 }
1000 if (tp->rx_opt.dsack) {
1001 tp->rx_opt.dsack = 0;
1002 tp->rx_opt.eff_sacks--;
1003 }
1004 }
1005}
1006
1007/* Construct a tcp options header for a SYN or SYN_ACK packet.
1008 * If this is every changed make sure to change the definition of
1009 * MAX_SYN_SIZE to match the new maximum number of options that you
1010 * can generate.
1011 */
1012static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
1013 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent)
1014{
1015 /* We always get an MSS option.
1016 * The option bytes which will be seen in normal data
1017 * packets should timestamps be used, must be in the MSS
1018 * advertised. But we subtract them from tp->mss_cache so
1019 * that calculations in tcp_sendmsg are simpler etc.
1020 * So account for this fact here if necessary. If we
1021 * don't do this correctly, as a receiver we won't
1022 * recognize data packets as being full sized when we
1023 * should, and thus we won't abide by the delayed ACK
1024 * rules correctly.
1025 * SACKs don't matter, we never delay an ACK when we
1026 * have any of those going out.
1027 */
1028 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
1029 if (ts) {
1030 if(sack)
1031 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) |
1032 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1033 else
1034 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1035 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1036 *ptr++ = htonl(tstamp); /* TSVAL */
1037 *ptr++ = htonl(ts_recent); /* TSECR */
1038 } else if(sack)
1039 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1040 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM);
1041 if (offer_wscale)
1042 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale));
1043}
1044
1045/* Determine a window scaling and initial window to offer. */
1046extern void tcp_select_initial_window(int __space, __u32 mss,
1047 __u32 *rcv_wnd, __u32 *window_clamp,
1048 int wscale_ok, __u8 *rcv_wscale);
1049
1050static inline int tcp_win_from_space(int space)
1051{
1052 return sysctl_tcp_adv_win_scale<=0 ?
1053 (space>>(-sysctl_tcp_adv_win_scale)) :
1054 space - (space>>sysctl_tcp_adv_win_scale);
1055}
1056
1057/* Note: caller must be prepared to deal with negative returns */
1058static inline int tcp_space(const struct sock *sk)
1059{
1060 return tcp_win_from_space(sk->sk_rcvbuf -
1061 atomic_read(&sk->sk_rmem_alloc));
1062}
1063
1064static inline int tcp_full_space(const struct sock *sk)
1065{
1066 return tcp_win_from_space(sk->sk_rcvbuf);
1067}
1068
60236fdd 1069static __inline__ void tcp_openreq_init(struct request_sock *req,
1da177e4
LT		 1070 struct tcp_options_received *rx_opt,
1071 struct sk_buff *skb)
1072{
2e6599cb
ACM		 1073 struct inet_request_sock *ireq = inet_rsk(req);
1074
1da177e4 1075 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
2e6599cb 1076 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1da177e4
LT		 1077 req->mss = rx_opt->mss_clamp;
1078 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
2e6599cb
ACM		 1079 ireq->tstamp_ok = rx_opt->tstamp_ok;
1080 ireq->sack_ok = rx_opt->sack_ok;
1081 ireq->snd_wscale = rx_opt->snd_wscale;
1082 ireq->wscale_ok = rx_opt->wscale_ok;
1083 ireq->acked = 0;
1084 ireq->ecn_ok = 0;
1085 ireq->rmt_port = skb->h.th->source;
1da177e4
LT		 1086}
1087
1088extern void tcp_enter_memory_pressure(void);
1089
1da177e4
LT		 1090static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1091{
1092 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1093}
1094
1095static inline int keepalive_time_when(const struct tcp_sock *tp)
1096{
1097 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1098}
1099
463c84b9 1100static inline int tcp_fin_time(const struct sock *sk)
1da177e4 1101{
463c84b9
ACM		 1102 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1103 const int rto = inet_csk(sk)->icsk_rto;
1da177e4 1104
463c84b9
ACM		 1105 if (fin_timeout < (rto << 2) - (rto >> 1))
1106 fin_timeout = (rto << 2) - (rto >> 1);
1da177e4
LT		 1107
1108 return fin_timeout;
1109}
1110
1111static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1112{
1113 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1114 return 0;
1115 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1116 return 0;
1117
1118 /* RST segments are not recommended to carry timestamp,
1119 and, if they do, it is recommended to ignore PAWS because
1120 "their cleanup function should take precedence over timestamps."
1121 Certainly, it is mistake. It is necessary to understand the reasons
1122 of this constraint to relax it: if peer reboots, clock may go
1123 out-of-sync and half-open connections will not be reset.
1124 Actually, the problem would be not existing if all
1125 the implementations followed draft about maintaining clock
1126 via reboots. Linux-2.2 DOES NOT!
1127
1128 However, we can relax time bounds for RST segments to MSL.
1129 */
1130 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1131 return 0;
1132 return 1;
1133}
1134
1da177e4
LT		 1135#define TCP_CHECK_TIMER(sk) do { } while (0)
1136
1137static inline int tcp_use_frto(const struct sock *sk)
1138{
1139 const struct tcp_sock *tp = tcp_sk(sk);
1140
1141 /* F-RTO must be activated in sysctl and there must be some
1142 * unsent new data, and the advertised window should allow
1143 * sending it.
1144 */
1145 return (sysctl_tcp_frto && sk->sk_send_head &&
1146 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq,
1147 tp->snd_una + tp->snd_wnd));
1148}
1149
1150static inline void tcp_mib_init(void)
1151{
1152 /* See RFC 2012 */
1153 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1154 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1155 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1156 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1157}
1158
1159/* /proc */
1160enum tcp_seq_states {
1161 TCP_SEQ_STATE_LISTENING,
1162 TCP_SEQ_STATE_OPENREQ,
1163 TCP_SEQ_STATE_ESTABLISHED,
1164 TCP_SEQ_STATE_TIME_WAIT,
1165};
1166
1167struct tcp_seq_afinfo {
1168 struct module *owner;
1169 char *name;
1170 sa_family_t family;
1171 int (*seq_show) (struct seq_file *m, void *v);
1172 struct file_operations *seq_fops;
1173};
1174
1175struct tcp_iter_state {
1176 sa_family_t family;
1177 enum tcp_seq_states state;
1178 struct sock *syn_wait_sk;
1179 int bucket, sbucket, num, uid;
1180 struct seq_operations seq_ops;
1181};
1182
1183extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1184extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1185
20380731
ACM		 1186extern struct request_sock_ops tcp_request_sock_ops;
1187
1188extern int tcp_v4_destroy_sock(struct sock *sk);
1189
1190#ifdef CONFIG_PROC_FS
1191extern int tcp4_proc_init(void);
1192extern void tcp4_proc_exit(void);
1193#endif
1194
1195extern void tcp_v4_init(struct net_proto_family *ops);
1196extern void tcp_init(void);
1197
1da177e4 1198#endif /* _TCP_H */
kernel source for telekom puls (alcatel/mediatek)