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[ARM] S3C: Fix scaler1 clock rate information
[linux-2.6/openmoko-kernel.git] / include / net / tcp.h
blob438014d57610d3c22355746e7f73e73ec73a3785
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 *
10 * Authors: Ross Biro
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
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>
29 #include <linux/skbuff.h>
30 #include <linux/dmaengine.h>
31 #include <linux/crypto.h>
32 #include <linux/cryptohash.h>
33
34 #include <net/inet_connection_sock.h>
35 #include <net/inet_timewait_sock.h>
36 #include <net/inet_hashtables.h>
37 #include <net/checksum.h>
38 #include <net/request_sock.h>
39 #include <net/sock.h>
40 #include <net/snmp.h>
41 #include <net/ip.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
44
45 #include <linux/seq_file.h>
46
47 extern struct inet_hashinfo tcp_hashinfo;
48
49 extern atomic_t tcp_orphan_count;
50 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
51
52 #define MAX_TCP_HEADER (128 + MAX_HEADER)
53 #define MAX_TCP_OPTION_SPACE 40
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
67 /* The least MTU to use for probing */
68 #define TCP_BASE_MSS 512
69
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
99 * connection: ~180sec is RFC minimum */
100
101 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
102 * connection: ~180sec is RFC minimum */
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 */
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 */
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 */
168 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
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
178 #define TCPOLEN_MD5SIG 18
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
187 #define TCPOLEN_MD5SIG_ALIGNED 20
188 #define TCPOLEN_MSS_ALIGNED 4
189
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 */
193 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
194
195 extern struct inet_timewait_death_row tcp_death_row;
196
197 /* sysctl variables for tcp */
198 extern int sysctl_tcp_timestamps;
199 extern int sysctl_tcp_window_scaling;
200 extern int sysctl_tcp_sack;
201 extern int sysctl_tcp_fin_timeout;
202 extern int sysctl_tcp_keepalive_time;
203 extern int sysctl_tcp_keepalive_probes;
204 extern int sysctl_tcp_keepalive_intvl;
205 extern int sysctl_tcp_syn_retries;
206 extern int sysctl_tcp_synack_retries;
207 extern int sysctl_tcp_retries1;
208 extern int sysctl_tcp_retries2;
209 extern int sysctl_tcp_orphan_retries;
210 extern int sysctl_tcp_syncookies;
211 extern int sysctl_tcp_retrans_collapse;
212 extern int sysctl_tcp_stdurg;
213 extern int sysctl_tcp_rfc1337;
214 extern int sysctl_tcp_abort_on_overflow;
215 extern int sysctl_tcp_max_orphans;
216 extern int sysctl_tcp_fack;
217 extern int sysctl_tcp_reordering;
218 extern int sysctl_tcp_ecn;
219 extern int sysctl_tcp_dsack;
220 extern int sysctl_tcp_mem[3];
221 extern int sysctl_tcp_wmem[3];
222 extern int sysctl_tcp_rmem[3];
223 extern int sysctl_tcp_app_win;
224 extern int sysctl_tcp_adv_win_scale;
225 extern int sysctl_tcp_tw_reuse;
226 extern int sysctl_tcp_frto;
227 extern int sysctl_tcp_frto_response;
228 extern int sysctl_tcp_low_latency;
229 extern int sysctl_tcp_dma_copybreak;
230 extern int sysctl_tcp_nometrics_save;
231 extern int sysctl_tcp_moderate_rcvbuf;
232 extern int sysctl_tcp_tso_win_divisor;
233 extern int sysctl_tcp_abc;
234 extern int sysctl_tcp_mtu_probing;
235 extern int sysctl_tcp_base_mss;
236 extern int sysctl_tcp_workaround_signed_windows;
237 extern int sysctl_tcp_slow_start_after_idle;
238 extern int sysctl_tcp_max_ssthresh;
239
240 extern atomic_t tcp_memory_allocated;
241 extern atomic_t tcp_sockets_allocated;
242 extern int tcp_memory_pressure;
243
244 /*
245 * The next routines deal with comparing 32 bit unsigned ints
246 * and worry about wraparound (automatic with unsigned arithmetic).
247 */
248
249 static inline int before(__u32 seq1, __u32 seq2)
250 {
251 return (__s32)(seq1-seq2) < 0;
252 }
253 #define after(seq2, seq1) before(seq1, seq2)
254
255 /* is s2<=s1<=s3 ? */
256 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
257 {
258 return seq3 - seq2 >= seq1 - seq2;
259 }
260
261 static 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 }
267
268 extern struct proto tcp_prot;
269
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)
274
275 extern void tcp_v4_err(struct sk_buff *skb, u32);
276
277 extern void tcp_shutdown (struct sock *sk, int how);
278
279 extern int tcp_v4_rcv(struct sk_buff *skb);
280
281 extern int tcp_v4_remember_stamp(struct sock *sk);
282
283 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
284
285 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
286 struct msghdr *msg, size_t size);
287 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
288
289 extern int tcp_ioctl(struct sock *sk,
290 int cmd,
291 unsigned long arg);
292
293 extern int tcp_rcv_state_process(struct sock *sk,
294 struct sk_buff *skb,
295 struct tcphdr *th,
296 unsigned len);
297
298 extern int tcp_rcv_established(struct sock *sk,
299 struct sk_buff *skb,
300 struct tcphdr *th,
301 unsigned len);
302
303 extern void tcp_rcv_space_adjust(struct sock *sk);
304
305 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
306
307 extern int tcp_twsk_unique(struct sock *sk,
308 struct sock *sktw, void *twp);
309
310 extern void tcp_twsk_destructor(struct sock *sk);
311
312 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
313 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
314
315 static inline void tcp_dec_quickack_mode(struct sock *sk,
316 const unsigned int pkts)
317 {
318 struct inet_connection_sock *icsk = inet_csk(sk);
319
320 if (icsk->icsk_ack.quick) {
321 if (pkts >= icsk->icsk_ack.quick) {
322 icsk->icsk_ack.quick = 0;
323 /* Leaving quickack mode we deflate ATO. */
324 icsk->icsk_ack.ato = TCP_ATO_MIN;
325 } else
326 icsk->icsk_ack.quick -= pkts;
327 }
328 }
329
330 extern void tcp_enter_quickack_mode(struct sock *sk);
331
332 static 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
337 #define TCP_ECN_OK 1
338 #define TCP_ECN_QUEUE_CWR 2
339 #define TCP_ECN_DEMAND_CWR 4
340
341 static __inline__ void
342 TCP_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
348 enum 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
357 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
358 struct sk_buff *skb,
359 const struct tcphdr *th);
360
361 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
362 struct request_sock *req,
363 struct request_sock **prev);
364 extern int tcp_child_process(struct sock *parent,
365 struct sock *child,
366 struct sk_buff *skb);
367 extern int tcp_use_frto(struct sock *sk);
368 extern void tcp_enter_frto(struct sock *sk);
369 extern void tcp_enter_loss(struct sock *sk, int how);
370 extern void tcp_clear_retrans(struct tcp_sock *tp);
371 extern void tcp_update_metrics(struct sock *sk);
372
373 extern void tcp_close(struct sock *sk,
374 long timeout);
375 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
376
377 extern int tcp_getsockopt(struct sock *sk, int level,
378 int optname,
379 char __user *optval,
380 int __user *optlen);
381 extern int tcp_setsockopt(struct sock *sk, int level,
382 int optname, char __user *optval,
383 int optlen);
384 extern int compat_tcp_getsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int __user *optlen);
387 extern int compat_tcp_setsockopt(struct sock *sk,
388 int level, int optname,
389 char __user *optval, int optlen);
390 extern void tcp_set_keepalive(struct sock *sk, int val);
391 extern 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
396 extern void tcp_parse_options(struct sk_buff *skb,
397 struct tcp_options_received *opt_rx,
398 int estab);
399
400 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
401
402 /*
403 * TCP v4 functions exported for the inet6 API
404 */
405
406 extern void tcp_v4_send_check(struct sock *sk, int len,
407 struct sk_buff *skb);
408
409 extern int tcp_v4_conn_request(struct sock *sk,
410 struct sk_buff *skb);
411
412 extern struct sock * tcp_create_openreq_child(struct sock *sk,
413 struct request_sock *req,
414 struct sk_buff *skb);
415
416 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
417 struct sk_buff *skb,
418 struct request_sock *req,
419 struct dst_entry *dst);
420
421 extern int tcp_v4_do_rcv(struct sock *sk,
422 struct sk_buff *skb);
423
424 extern int tcp_v4_connect(struct sock *sk,
425 struct sockaddr *uaddr,
426 int addr_len);
427
428 extern int tcp_connect(struct sock *sk);
429
430 extern struct sk_buff * tcp_make_synack(struct sock *sk,
431 struct dst_entry *dst,
432 struct request_sock *req);
433
434 extern int tcp_disconnect(struct sock *sk, int flags);
435
436
437 /* From syncookies.c */
438 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
439 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
440 struct ip_options *opt);
441 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
442 __u16 *mss);
443
444 extern __u32 cookie_init_timestamp(struct request_sock *req);
445 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
446
447 /* From net/ipv6/syncookies.c */
448 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
449 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
450 __u16 *mss);
451
452 /* tcp_output.c */
453
454 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
455 int nonagle);
456 extern int tcp_may_send_now(struct sock *sk);
457 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
458 extern void tcp_xmit_retransmit_queue(struct sock *);
459 extern void tcp_simple_retransmit(struct sock *);
460 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
461 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
462
463 extern void tcp_send_probe0(struct sock *);
464 extern void tcp_send_partial(struct sock *);
465 extern int tcp_write_wakeup(struct sock *);
466 extern void tcp_send_fin(struct sock *sk);
467 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
468 extern int tcp_send_synack(struct sock *);
469 extern void tcp_push_one(struct sock *, unsigned int mss_now);
470 extern void tcp_send_ack(struct sock *sk);
471 extern void tcp_send_delayed_ack(struct sock *sk);
472
473 /* tcp_input.c */
474 extern void tcp_cwnd_application_limited(struct sock *sk);
475 extern void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp,
476 struct sk_buff *skb);
477
478 /* tcp_timer.c */
479 extern void tcp_init_xmit_timers(struct sock *);
480 static inline void tcp_clear_xmit_timers(struct sock *sk)
481 {
482 inet_csk_clear_xmit_timers(sk);
483 }
484
485 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
486 extern unsigned int tcp_current_mss(struct sock *sk, int large);
487
488 /* tcp.c */
489 extern void tcp_get_info(struct sock *, struct tcp_info *);
490
491 /* Read 'sendfile()'-style from a TCP socket */
492 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
493 unsigned int, size_t);
494 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
495 sk_read_actor_t recv_actor);
496
497 extern void tcp_initialize_rcv_mss(struct sock *sk);
498
499 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
500 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
501 extern void tcp_mtup_init(struct sock *sk);
502
503 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
504 {
505 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
506 ntohl(TCP_FLAG_ACK) |
507 snd_wnd);
508 }
509
510 static inline void tcp_fast_path_on(struct tcp_sock *tp)
511 {
512 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
513 }
514
515 static inline void tcp_fast_path_check(struct sock *sk)
516 {
517 struct tcp_sock *tp = tcp_sk(sk);
518
519 if (skb_queue_empty(&tp->out_of_order_queue) &&
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 */
530 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
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 */
543 extern 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
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
549 * casts with the following macro.
550 */
551 #define tcp_time_stamp ((__u32)(jiffies))
552
553 /* This is what the send packet queuing engine uses to pass
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 */
560 struct 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
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
599 /* Due to TSO, an SKB can be composed of multiple actual
600 * packets. To keep these tracked properly, we use this.
601 */
602 static inline int tcp_skb_pcount(const struct sk_buff *skb)
603 {
604 return skb_shinfo(skb)->gso_segs;
605 }
606
607 /* This is valid iff tcp_skb_pcount() > 1. */
608 static inline int tcp_skb_mss(const struct sk_buff *skb)
609 {
610 return skb_shinfo(skb)->gso_size;
611 }
612
613 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
614 {
615 if (*count) {
616 *count -= decr;
617 if ((int)*count < 0)
618 *count = 0;
619 }
620 }
621
622 static 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
628 /* Events passed to congestion control interface */
629 enum 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
643 #define TCP_CA_MAX 128
644 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
645
646 #define TCP_CONG_NON_RESTRICTED 0x1
647 #define TCP_CONG_RTT_STAMP 0x2
648
649 struct tcp_congestion_ops {
650 struct list_head list;
651 unsigned long flags;
652
653 /* initialize private data (optional) */
654 void (*init)(struct sock *sk);
655 /* cleanup private data (optional) */
656 void (*release)(struct sock *sk);
657
658 /* return slow start threshold (required) */
659 u32 (*ssthresh)(struct sock *sk);
660 /* lower bound for congestion window (optional) */
661 u32 (*min_cwnd)(const struct sock *sk);
662 /* do new cwnd calculation (required) */
663 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
664 /* call before changing ca_state (optional) */
665 void (*set_state)(struct sock *sk, u8 new_state);
666 /* call when cwnd event occurs (optional) */
667 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
668 /* new value of cwnd after loss (optional) */
669 u32 (*undo_cwnd)(struct sock *sk);
670 /* hook for packet ack accounting (optional) */
671 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
672 /* get info for inet_diag (optional) */
673 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
674
675 char name[TCP_CA_NAME_MAX];
676 struct module *owner;
677 };
678
679 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
680 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
681
682 extern void tcp_init_congestion_control(struct sock *sk);
683 extern void tcp_cleanup_congestion_control(struct sock *sk);
684 extern int tcp_set_default_congestion_control(const char *name);
685 extern void tcp_get_default_congestion_control(char *name);
686 extern void tcp_get_available_congestion_control(char *buf, size_t len);
687 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
688 extern int tcp_set_allowed_congestion_control(char *allowed);
689 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
690 extern void tcp_slow_start(struct tcp_sock *tp);
691
692 extern struct tcp_congestion_ops tcp_init_congestion_ops;
693 extern u32 tcp_reno_ssthresh(struct sock *sk);
694 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
695 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
696 extern struct tcp_congestion_ops tcp_reno;
697
698 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
699 {
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;
705 }
706
707 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
708 {
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);
713 }
714
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 */
723 static inline int tcp_is_sack(const struct tcp_sock *tp)
724 {
725 return tp->rx_opt.sack_ok;
726 }
727
728 static inline int tcp_is_reno(const struct tcp_sock *tp)
729 {
730 return !tcp_is_sack(tp);
731 }
732
733 static inline int tcp_is_fack(const struct tcp_sock *tp)
734 {
735 return tp->rx_opt.sack_ok & 2;
736 }
737
738 static inline void tcp_enable_fack(struct tcp_sock *tp)
739 {
740 tp->rx_opt.sack_ok |= 2;
741 }
742
743 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
744 {
745 return tp->sacked_out + tp->lost_out;
746 }
747
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 */
762 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
763 {
764 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
765 }
766
767 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
768
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 */
773 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
774 {
775 const struct tcp_sock *tp = tcp_sk(sk);
776 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
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
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)
786
787 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
788 extern __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
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.
795 */
796 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
797 {
798 return tp->reordering;
799 }
800
801 /* Returns end sequence number of the receiver's advertised window */
802 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
803 {
804 return tp->snd_una + tp->snd_wnd;
805 }
806 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
807
808 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
809 const struct sk_buff *skb)
810 {
811 if (skb->len < mss)
812 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
813 }
814
815 static inline void tcp_check_probe_timer(struct sock *sk)
816 {
817 struct tcp_sock *tp = tcp_sk(sk);
818 const struct inet_connection_sock *icsk = inet_csk(sk);
819
820 if (!tp->packets_out && !icsk->icsk_pending)
821 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
822 icsk->icsk_rto, TCP_RTO_MAX);
823 }
824
825 static inline void tcp_push_pending_frames(struct sock *sk)
826 {
827 struct tcp_sock *tp = tcp_sk(sk);
828
829 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
830 }
831
832 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
833 {
834 tp->snd_wl1 = seq;
835 }
836
837 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
838 {
839 tp->snd_wl1 = seq;
840 }
841
842 /*
843 * Calculate(/check) TCP checksum
844 */
845 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
846 __be32 daddr, __wsum base)
847 {
848 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
849 }
850
851 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
852 {
853 return __skb_checksum_complete(skb);
854 }
855
856 static inline int tcp_checksum_complete(struct sk_buff *skb)
857 {
858 return !skb_csum_unnecessary(skb) &&
859 __tcp_checksum_complete(skb);
860 }
861
862 /* Prequeue for VJ style copy to user, combined with checksumming. */
863
864 static inline void tcp_prequeue_init(struct tcp_sock *tp)
865 {
866 tp->ucopy.task = NULL;
867 tp->ucopy.len = 0;
868 tp->ucopy.memory = 0;
869 skb_queue_head_init(&tp->ucopy.prequeue);
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
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 */
886 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
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_backlog_rcv(sk, skb1);
900 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED);
901 }
902
903 tp->ucopy.memory = 0;
904 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
905 wake_up_interruptible(sk->sk_sleep);
906 if (!inet_csk_ack_scheduled(sk))
907 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
908 (3 * TCP_RTO_MIN) / 4,
909 TCP_RTO_MAX);
910 }
911 return 1;
912 }
913 return 0;
914 }
915
916
917 #undef STATE_TRACE
918
919 #ifdef STATE_TRACE
920 static 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
926 extern void tcp_set_state(struct sock *sk, int state);
927
928 extern void tcp_done(struct sock *sk);
929
930 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
931 {
932 rx_opt->dsack = 0;
933 rx_opt->eff_sacks = 0;
934 rx_opt->num_sacks = 0;
935 }
936
937 /* Determine a window scaling and initial window to offer. */
938 extern void tcp_select_initial_window(int __space, __u32 mss,
939 __u32 *rcv_wnd, __u32 *window_clamp,
940 int wscale_ok, __u8 *rcv_wscale);
941
942 static 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 */
950 static 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
956 static inline int tcp_full_space(const struct sock *sk)
957 {
958 return tcp_win_from_space(sk->sk_rcvbuf);
959 }
960
961 static inline void tcp_openreq_init(struct request_sock *req,
962 struct tcp_options_received *rx_opt,
963 struct sk_buff *skb)
964 {
965 struct inet_request_sock *ireq = inet_rsk(req);
966
967 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
968 req->cookie_ts = 0;
969 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
970 req->mss = rx_opt->mss_clamp;
971 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
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;
978 ireq->rmt_port = tcp_hdr(skb)->source;
979 ireq->loc_port = tcp_hdr(skb)->dest;
980 }
981
982 extern void tcp_enter_memory_pressure(struct sock *sk);
983
984 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
985 {
986 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
987 }
988
989 static inline int keepalive_time_when(const struct tcp_sock *tp)
990 {
991 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
992 }
993
994 static inline int tcp_fin_time(const struct sock *sk)
995 {
996 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
997 const int rto = inet_csk(sk)->icsk_rto;
998
999 if (fin_timeout < (rto << 2) - (rto >> 1))
1000 fin_timeout = (rto << 2) - (rto >> 1);
1001
1002 return fin_timeout;
1003 }
1004
1005 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1006 {
1007 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1008 return 0;
1009 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1010 return 0;
1011
1012 /* RST segments are not recommended to carry timestamp,
1013 and, if they do, it is recommended to ignore PAWS because
1014 "their cleanup function should take precedence over timestamps."
1015 Certainly, it is mistake. It is necessary to understand the reasons
1016 of this constraint to relax it: if peer reboots, clock may go
1017 out-of-sync and half-open connections will not be reset.
1018 Actually, the problem would be not existing if all
1019 the implementations followed draft about maintaining clock
1020 via reboots. Linux-2.2 DOES NOT!
1021
1022 However, we can relax time bounds for RST segments to MSL.
1023 */
1024 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1025 return 0;
1026 return 1;
1027 }
1028
1029 #define TCP_CHECK_TIMER(sk) do { } while (0)
1030
1031 static inline void tcp_mib_init(struct net *net)
1032 {
1033 /* See RFC 2012 */
1034 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1035 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1036 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1037 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1038 }
1039
1040 /* from STCP */
1041 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1042 {
1043 tp->lost_skb_hint = NULL;
1044 tp->scoreboard_skb_hint = NULL;
1045 }
1046
1047 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1048 {
1049 tcp_clear_retrans_hints_partial(tp);
1050 tp->retransmit_skb_hint = NULL;
1051 }
1052
1053 /* MD5 Signature */
1054 struct crypto_hash;
1055
1056 /* - key database */
1057 struct tcp_md5sig_key {
1058 u8 *key;
1059 u8 keylen;
1060 };
1061
1062 struct tcp4_md5sig_key {
1063 struct tcp_md5sig_key base;
1064 __be32 addr;
1065 };
1066
1067 struct tcp6_md5sig_key {
1068 struct tcp_md5sig_key base;
1069 #if 0
1070 u32 scope_id; /* XXX */
1071 #endif
1072 struct in6_addr addr;
1073 };
1074
1075 /* - sock block */
1076 struct tcp_md5sig_info {
1077 struct tcp4_md5sig_key *keys4;
1078 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1079 struct tcp6_md5sig_key *keys6;
1080 u32 entries6;
1081 u32 alloced6;
1082 #endif
1083 u32 entries4;
1084 u32 alloced4;
1085 };
1086
1087 /* - pseudo header */
1088 struct tcp4_pseudohdr {
1089 __be32 saddr;
1090 __be32 daddr;
1091 __u8 pad;
1092 __u8 protocol;
1093 __be16 len;
1094 };
1095
1096 struct tcp6_pseudohdr {
1097 struct in6_addr saddr;
1098 struct in6_addr daddr;
1099 __be32 len;
1100 __be32 protocol; /* including padding */
1101 };
1102
1103 union tcp_md5sum_block {
1104 struct tcp4_pseudohdr ip4;
1105 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1106 struct tcp6_pseudohdr ip6;
1107 #endif
1108 };
1109
1110 /* - pool: digest algorithm, hash description and scratch buffer */
1111 struct tcp_md5sig_pool {
1112 struct hash_desc md5_desc;
1113 union tcp_md5sum_block md5_blk;
1114 };
1115
1116 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1117
1118 /* - functions */
1119 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1120 struct tcp_md5sig_key *key,
1121 struct sock *sk,
1122 struct request_sock *req,
1123 struct sk_buff *skb);
1124
1125 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1126 struct sock *addr_sk);
1127
1128 extern int tcp_v4_md5_do_add(struct sock *sk,
1129 __be32 addr,
1130 u8 *newkey,
1131 u8 newkeylen);
1132
1133 extern int tcp_v4_md5_do_del(struct sock *sk,
1134 __be32 addr);
1135
1136 #ifdef CONFIG_TCP_MD5SIG
1137 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1138 &(struct tcp_md5sig_key) { \
1139 .key = (twsk)->tw_md5_key, \
1140 .keylen = (twsk)->tw_md5_keylen, \
1141 } : NULL)
1142 #else
1143 #define tcp_twsk_md5_key(twsk) NULL
1144 #endif
1145
1146 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1147 extern void tcp_free_md5sig_pool(void);
1148
1149 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1150 extern void __tcp_put_md5sig_pool(void);
1151 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1152 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1153 unsigned header_len);
1154 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1155 struct tcp_md5sig_key *key);
1156
1157 static inline
1158 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1159 {
1160 int cpu = get_cpu();
1161 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1162 if (!ret)
1163 put_cpu();
1164 return ret;
1165 }
1166
1167 static inline void tcp_put_md5sig_pool(void)
1168 {
1169 __tcp_put_md5sig_pool();
1170 put_cpu();
1171 }
1172
1173 /* write queue abstraction */
1174 static inline void tcp_write_queue_purge(struct sock *sk)
1175 {
1176 struct sk_buff *skb;
1177
1178 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1179 sk_wmem_free_skb(sk, skb);
1180 sk_mem_reclaim(sk);
1181 }
1182
1183 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1184 {
1185 return skb_peek(&sk->sk_write_queue);
1186 }
1187
1188 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1189 {
1190 return skb_peek_tail(&sk->sk_write_queue);
1191 }
1192
1193 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1194 {
1195 return skb_queue_next(&sk->sk_write_queue, skb);
1196 }
1197
1198 #define tcp_for_write_queue(skb, sk) \
1199 skb_queue_walk(&(sk)->sk_write_queue, skb)
1200
1201 #define tcp_for_write_queue_from(skb, sk) \
1202 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1203
1204 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1205 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1206
1207 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1208 {
1209 return sk->sk_send_head;
1210 }
1211
1212 static inline bool tcp_skb_is_last(const struct sock *sk,
1213 const struct sk_buff *skb)
1214 {
1215 return skb_queue_is_last(&sk->sk_write_queue, skb);
1216 }
1217
1218 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1219 {
1220 if (tcp_skb_is_last(sk, skb))
1221 sk->sk_send_head = NULL;
1222 else
1223 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1224 }
1225
1226 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1227 {
1228 if (sk->sk_send_head == skb_unlinked)
1229 sk->sk_send_head = NULL;
1230 }
1231
1232 static inline void tcp_init_send_head(struct sock *sk)
1233 {
1234 sk->sk_send_head = NULL;
1235 }
1236
1237 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1238 {
1239 __skb_queue_tail(&sk->sk_write_queue, skb);
1240 }
1241
1242 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1243 {
1244 __tcp_add_write_queue_tail(sk, skb);
1245
1246 /* Queue it, remembering where we must start sending. */
1247 if (sk->sk_send_head == NULL) {
1248 sk->sk_send_head = skb;
1249
1250 if (tcp_sk(sk)->highest_sack == NULL)
1251 tcp_sk(sk)->highest_sack = skb;
1252 }
1253 }
1254
1255 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1256 {
1257 __skb_queue_head(&sk->sk_write_queue, skb);
1258 }
1259
1260 /* Insert buff after skb on the write queue of sk. */
1261 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1262 struct sk_buff *buff,
1263 struct sock *sk)
1264 {
1265 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1266 }
1267
1268 /* Insert new before skb on the write queue of sk. */
1269 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1270 struct sk_buff *skb,
1271 struct sock *sk)
1272 {
1273 __skb_queue_before(&sk->sk_write_queue, skb, new);
1274
1275 if (sk->sk_send_head == skb)
1276 sk->sk_send_head = new;
1277 }
1278
1279 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1280 {
1281 __skb_unlink(skb, &sk->sk_write_queue);
1282 }
1283
1284 static inline int tcp_write_queue_empty(struct sock *sk)
1285 {
1286 return skb_queue_empty(&sk->sk_write_queue);
1287 }
1288
1289 /* Start sequence of the highest skb with SACKed bit, valid only if
1290 * sacked > 0 or when the caller has ensured validity by itself.
1291 */
1292 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1293 {
1294 if (!tp->sacked_out)
1295 return tp->snd_una;
1296
1297 if (tp->highest_sack == NULL)
1298 return tp->snd_nxt;
1299
1300 return TCP_SKB_CB(tp->highest_sack)->seq;
1301 }
1302
1303 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1304 {
1305 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1306 tcp_write_queue_next(sk, skb);
1307 }
1308
1309 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1310 {
1311 return tcp_sk(sk)->highest_sack;
1312 }
1313
1314 static inline void tcp_highest_sack_reset(struct sock *sk)
1315 {
1316 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1317 }
1318
1319 /* Called when old skb is about to be deleted (to be combined with new skb) */
1320 static inline void tcp_highest_sack_combine(struct sock *sk,
1321 struct sk_buff *old,
1322 struct sk_buff *new)
1323 {
1324 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1325 tcp_sk(sk)->highest_sack = new;
1326 }
1327
1328 /* /proc */
1329 enum tcp_seq_states {
1330 TCP_SEQ_STATE_LISTENING,
1331 TCP_SEQ_STATE_OPENREQ,
1332 TCP_SEQ_STATE_ESTABLISHED,
1333 TCP_SEQ_STATE_TIME_WAIT,
1334 };
1335
1336 struct tcp_seq_afinfo {
1337 char *name;
1338 sa_family_t family;
1339 struct file_operations seq_fops;
1340 struct seq_operations seq_ops;
1341 };
1342
1343 struct tcp_iter_state {
1344 struct seq_net_private p;
1345 sa_family_t family;
1346 enum tcp_seq_states state;
1347 struct sock *syn_wait_sk;
1348 int bucket, sbucket, num, uid;
1349 };
1350
1351 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1352 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1353
1354 extern struct request_sock_ops tcp_request_sock_ops;
1355 extern struct request_sock_ops tcp6_request_sock_ops;
1356
1357 extern void tcp_v4_destroy_sock(struct sock *sk);
1358
1359 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1360 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1361
1362 #ifdef CONFIG_PROC_FS
1363 extern int tcp4_proc_init(void);
1364 extern void tcp4_proc_exit(void);
1365 #endif
1366
1367 /* TCP af-specific functions */
1368 struct tcp_sock_af_ops {
1369 #ifdef CONFIG_TCP_MD5SIG
1370 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1371 struct sock *addr_sk);
1372 int (*calc_md5_hash) (char *location,
1373 struct tcp_md5sig_key *md5,
1374 struct sock *sk,
1375 struct request_sock *req,
1376 struct sk_buff *skb);
1377 int (*md5_add) (struct sock *sk,
1378 struct sock *addr_sk,
1379 u8 *newkey,
1380 u8 len);
1381 int (*md5_parse) (struct sock *sk,
1382 char __user *optval,
1383 int optlen);
1384 #endif
1385 };
1386
1387 struct tcp_request_sock_ops {
1388 #ifdef CONFIG_TCP_MD5SIG
1389 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1390 struct request_sock *req);
1391 #endif
1392 };
1393
1394 extern void tcp_v4_init(void);
1395 extern void tcp_init(void);
1396
1397 #endif /* _TCP_H */
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