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tcp md5sig: Let the caller pass appropriate key for tcp_v{4,6}_do_calc_md5_hash().
[linux-2.6/kvm.git] / include / net / tcp.h
blob07005ebb47a731c74656c826ac640412b8d870ba
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
54 /*
55 * Never offer a window over 32767 without using window scaling. Some
56 * poor stacks do signed 16bit maths!
57 */
58 #define MAX_TCP_WINDOW 32767U
59
60 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
61 #define TCP_MIN_MSS 88U
62
63 /* Minimal RCV_MSS. */
64 #define TCP_MIN_RCVMSS 536U
65
66 /* The least MTU to use for probing */
67 #define TCP_BASE_MSS 512
68
69 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
70 #define TCP_FASTRETRANS_THRESH 3
71
72 /* Maximal reordering. */
73 #define TCP_MAX_REORDERING 127
74
75 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
76 #define TCP_MAX_QUICKACKS 16U
77
78 /* urg_data states */
79 #define TCP_URG_VALID 0x0100
80 #define TCP_URG_NOTYET 0x0200
81 #define TCP_URG_READ 0x0400
82
83 #define TCP_RETR1 3 /*
84 * This is how many retries it does before it
85 * tries to figure out if the gateway is
86 * down. Minimal RFC value is 3; it corresponds
87 * to ~3sec-8min depending on RTO.
88 */
89
90 #define TCP_RETR2 15 /*
91 * This should take at least
92 * 90 minutes to time out.
93 * RFC1122 says that the limit is 100 sec.
94 * 15 is ~13-30min depending on RTO.
95 */
96
97 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
98 * connection: ~180sec is RFC minimum */
99
100 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
101 * connection: ~180sec is RFC minimum */
102
103
104 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
105 * socket. 7 is ~50sec-16min.
106 */
107
108
109 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
110 * state, about 60 seconds */
111 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
112 /* BSD style FIN_WAIT2 deadlock breaker.
113 * It used to be 3min, new value is 60sec,
114 * to combine FIN-WAIT-2 timeout with
115 * TIME-WAIT timer.
116 */
117
118 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119 #if HZ >= 100
120 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
121 #define TCP_ATO_MIN ((unsigned)(HZ/25))
122 #else
123 #define TCP_DELACK_MIN 4U
124 #define TCP_ATO_MIN 4U
125 #endif
126 #define TCP_RTO_MAX ((unsigned)(120*HZ))
127 #define TCP_RTO_MIN ((unsigned)(HZ/5))
128 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129
130 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
131 * for local resources.
132 */
133
134 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
135 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
136 #define TCP_KEEPALIVE_INTVL (75*HZ)
137
138 #define MAX_TCP_KEEPIDLE 32767
139 #define MAX_TCP_KEEPINTVL 32767
140 #define MAX_TCP_KEEPCNT 127
141 #define MAX_TCP_SYNCNT 127
142 #define MAX_TCP_ACCEPT_DEFERRED 65535
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
189 /* Flags in tp->nonagle */
190 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
191 #define TCP_NAGLE_CORK 2 /* Socket is corked */
192 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
193
194 extern struct inet_timewait_death_row tcp_death_row;
195
196 /* sysctl variables for tcp */
197 extern int sysctl_tcp_timestamps;
198 extern int sysctl_tcp_window_scaling;
199 extern int sysctl_tcp_sack;
200 extern int sysctl_tcp_fin_timeout;
201 extern int sysctl_tcp_keepalive_time;
202 extern int sysctl_tcp_keepalive_probes;
203 extern int sysctl_tcp_keepalive_intvl;
204 extern int sysctl_tcp_syn_retries;
205 extern int sysctl_tcp_synack_retries;
206 extern int sysctl_tcp_retries1;
207 extern int sysctl_tcp_retries2;
208 extern int sysctl_tcp_orphan_retries;
209 extern int sysctl_tcp_syncookies;
210 extern int sysctl_tcp_retrans_collapse;
211 extern int sysctl_tcp_stdurg;
212 extern int sysctl_tcp_rfc1337;
213 extern int sysctl_tcp_abort_on_overflow;
214 extern int sysctl_tcp_max_orphans;
215 extern int sysctl_tcp_fack;
216 extern int sysctl_tcp_reordering;
217 extern int sysctl_tcp_ecn;
218 extern int sysctl_tcp_dsack;
219 extern int sysctl_tcp_mem[3];
220 extern int sysctl_tcp_wmem[3];
221 extern int sysctl_tcp_rmem[3];
222 extern int sysctl_tcp_app_win;
223 extern int sysctl_tcp_adv_win_scale;
224 extern int sysctl_tcp_tw_reuse;
225 extern int sysctl_tcp_frto;
226 extern int sysctl_tcp_frto_response;
227 extern int sysctl_tcp_low_latency;
228 extern int sysctl_tcp_dma_copybreak;
229 extern int sysctl_tcp_nometrics_save;
230 extern int sysctl_tcp_moderate_rcvbuf;
231 extern int sysctl_tcp_tso_win_divisor;
232 extern int sysctl_tcp_abc;
233 extern int sysctl_tcp_mtu_probing;
234 extern int sysctl_tcp_base_mss;
235 extern int sysctl_tcp_workaround_signed_windows;
236 extern int sysctl_tcp_slow_start_after_idle;
237 extern int sysctl_tcp_max_ssthresh;
238
239 extern atomic_t tcp_memory_allocated;
240 extern atomic_t tcp_sockets_allocated;
241 extern int tcp_memory_pressure;
242
243 /*
244 * The next routines deal with comparing 32 bit unsigned ints
245 * and worry about wraparound (automatic with unsigned arithmetic).
246 */
247
248 static inline int before(__u32 seq1, __u32 seq2)
249 {
250 return (__s32)(seq1-seq2) < 0;
251 }
252 #define after(seq2, seq1) before(seq1, seq2)
253
254 /* is s2<=s1<=s3 ? */
255 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
256 {
257 return seq3 - seq2 >= seq1 - seq2;
258 }
259
260 static inline int tcp_too_many_orphans(struct sock *sk, int num)
261 {
262 return (num > sysctl_tcp_max_orphans) ||
263 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
264 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
265 }
266
267 extern struct proto tcp_prot;
268
269 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
270 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
271 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
272 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
273 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
274 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
275 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
276
277 extern void tcp_v4_err(struct sk_buff *skb, u32);
278
279 extern void tcp_shutdown (struct sock *sk, int how);
280
281 extern int tcp_v4_rcv(struct sk_buff *skb);
282
283 extern int tcp_v4_remember_stamp(struct sock *sk);
284
285 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
286
287 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
288 struct msghdr *msg, size_t size);
289 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
290
291 extern int tcp_ioctl(struct sock *sk,
292 int cmd,
293 unsigned long arg);
294
295 extern int tcp_rcv_state_process(struct sock *sk,
296 struct sk_buff *skb,
297 struct tcphdr *th,
298 unsigned len);
299
300 extern int tcp_rcv_established(struct sock *sk,
301 struct sk_buff *skb,
302 struct tcphdr *th,
303 unsigned len);
304
305 extern void tcp_rcv_space_adjust(struct sock *sk);
306
307 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
308
309 extern int tcp_twsk_unique(struct sock *sk,
310 struct sock *sktw, void *twp);
311
312 extern void tcp_twsk_destructor(struct sock *sk);
313
314 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
315 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
316
317 static inline void tcp_dec_quickack_mode(struct sock *sk,
318 const unsigned int pkts)
319 {
320 struct inet_connection_sock *icsk = inet_csk(sk);
321
322 if (icsk->icsk_ack.quick) {
323 if (pkts >= icsk->icsk_ack.quick) {
324 icsk->icsk_ack.quick = 0;
325 /* Leaving quickack mode we deflate ATO. */
326 icsk->icsk_ack.ato = TCP_ATO_MIN;
327 } else
328 icsk->icsk_ack.quick -= pkts;
329 }
330 }
331
332 extern void tcp_enter_quickack_mode(struct sock *sk);
333
334 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
335 {
336 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
337 }
338
339 #define TCP_ECN_OK 1
340 #define TCP_ECN_QUEUE_CWR 2
341 #define TCP_ECN_DEMAND_CWR 4
342
343 static __inline__ void
344 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
345 {
346 if (sysctl_tcp_ecn && th->ece && th->cwr)
347 inet_rsk(req)->ecn_ok = 1;
348 }
349
350 enum tcp_tw_status
351 {
352 TCP_TW_SUCCESS = 0,
353 TCP_TW_RST = 1,
354 TCP_TW_ACK = 2,
355 TCP_TW_SYN = 3
356 };
357
358
359 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
360 struct sk_buff *skb,
361 const struct tcphdr *th);
362
363 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
364 struct request_sock *req,
365 struct request_sock **prev);
366 extern int tcp_child_process(struct sock *parent,
367 struct sock *child,
368 struct sk_buff *skb);
369 extern int tcp_use_frto(struct sock *sk);
370 extern void tcp_enter_frto(struct sock *sk);
371 extern void tcp_enter_loss(struct sock *sk, int how);
372 extern void tcp_clear_retrans(struct tcp_sock *tp);
373 extern void tcp_update_metrics(struct sock *sk);
374
375 extern void tcp_close(struct sock *sk,
376 long timeout);
377 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
378
379 extern int tcp_getsockopt(struct sock *sk, int level,
380 int optname,
381 char __user *optval,
382 int __user *optlen);
383 extern int tcp_setsockopt(struct sock *sk, int level,
384 int optname, char __user *optval,
385 int optlen);
386 extern int compat_tcp_getsockopt(struct sock *sk,
387 int level, int optname,
388 char __user *optval, int __user *optlen);
389 extern int compat_tcp_setsockopt(struct sock *sk,
390 int level, int optname,
391 char __user *optval, int optlen);
392 extern void tcp_set_keepalive(struct sock *sk, int val);
393 extern 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
398 extern void tcp_parse_options(struct sk_buff *skb,
399 struct tcp_options_received *opt_rx,
400 int estab);
401
402 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
403
404 /*
405 * TCP v4 functions exported for the inet6 API
406 */
407
408 extern void tcp_v4_send_check(struct sock *sk, int len,
409 struct sk_buff *skb);
410
411 extern int tcp_v4_conn_request(struct sock *sk,
412 struct sk_buff *skb);
413
414 extern struct sock * tcp_create_openreq_child(struct sock *sk,
415 struct request_sock *req,
416 struct sk_buff *skb);
417
418 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
419 struct sk_buff *skb,
420 struct request_sock *req,
421 struct dst_entry *dst);
422
423 extern int tcp_v4_do_rcv(struct sock *sk,
424 struct sk_buff *skb);
425
426 extern int tcp_v4_connect(struct sock *sk,
427 struct sockaddr *uaddr,
428 int addr_len);
429
430 extern int tcp_connect(struct sock *sk);
431
432 extern struct sk_buff * tcp_make_synack(struct sock *sk,
433 struct dst_entry *dst,
434 struct request_sock *req);
435
436 extern int tcp_disconnect(struct sock *sk, int flags);
437
438 extern void tcp_unhash(struct sock *sk);
439
440 /* From syncookies.c */
441 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
442 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
443 struct ip_options *opt);
444 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
445 __u16 *mss);
446
447 extern __u32 cookie_init_timestamp(struct request_sock *req);
448 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
449
450 /* From net/ipv6/syncookies.c */
451 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
452 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
453 __u16 *mss);
454
455 /* tcp_output.c */
456
457 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
458 int nonagle);
459 extern int tcp_may_send_now(struct sock *sk);
460 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
461 extern void tcp_xmit_retransmit_queue(struct sock *);
462 extern void tcp_simple_retransmit(struct sock *);
463 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
464 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
465
466 extern void tcp_send_probe0(struct sock *);
467 extern void tcp_send_partial(struct sock *);
468 extern int tcp_write_wakeup(struct sock *);
469 extern void tcp_send_fin(struct sock *sk);
470 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
471 extern int tcp_send_synack(struct sock *);
472 extern void tcp_push_one(struct sock *, unsigned int mss_now);
473 extern void tcp_send_ack(struct sock *sk);
474 extern void tcp_send_delayed_ack(struct sock *sk);
475
476 /* tcp_input.c */
477 extern void tcp_cwnd_application_limited(struct sock *sk);
478
479 /* tcp_timer.c */
480 extern void tcp_init_xmit_timers(struct sock *);
481 static inline void tcp_clear_xmit_timers(struct sock *sk)
482 {
483 inet_csk_clear_xmit_timers(sk);
484 }
485
486 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
487 extern unsigned int tcp_current_mss(struct sock *sk, int large);
488
489 /* tcp.c */
490 extern void tcp_get_info(struct sock *, struct tcp_info *);
491
492 /* Read 'sendfile()'-style from a TCP socket */
493 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
494 unsigned int, size_t);
495 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
496 sk_read_actor_t recv_actor);
497
498 extern void tcp_initialize_rcv_mss(struct sock *sk);
499
500 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
501 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
502 extern void tcp_mtup_init(struct sock *sk);
503
504 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
505 {
506 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
507 ntohl(TCP_FLAG_ACK) |
508 snd_wnd);
509 }
510
511 static inline void tcp_fast_path_on(struct tcp_sock *tp)
512 {
513 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
514 }
515
516 static inline void tcp_fast_path_check(struct sock *sk)
517 {
518 struct tcp_sock *tp = tcp_sk(sk);
519
520 if (skb_queue_empty(&tp->out_of_order_queue) &&
521 tp->rcv_wnd &&
522 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
523 !tp->urg_data)
524 tcp_fast_path_on(tp);
525 }
526
527 /* Compute the actual receive window we are currently advertising.
528 * Rcv_nxt can be after the window if our peer push more data
529 * than the offered window.
530 */
531 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
532 {
533 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
534
535 if (win < 0)
536 win = 0;
537 return (u32) win;
538 }
539
540 /* Choose a new window, without checks for shrinking, and without
541 * scaling applied to the result. The caller does these things
542 * if necessary. This is a "raw" window selection.
543 */
544 extern u32 __tcp_select_window(struct sock *sk);
545
546 /* TCP timestamps are only 32-bits, this causes a slight
547 * complication on 64-bit systems since we store a snapshot
548 * of jiffies in the buffer control blocks below. We decided
549 * to use only the low 32-bits of jiffies and hide the ugly
550 * casts with the following macro.
551 */
552 #define tcp_time_stamp ((__u32)(jiffies))
553
554 /* This is what the send packet queuing engine uses to pass
555 * TCP per-packet control information to the transmission
556 * code. We also store the host-order sequence numbers in
557 * here too. This is 36 bytes on 32-bit architectures,
558 * 40 bytes on 64-bit machines, if this grows please adjust
559 * skbuff.h:skbuff->cb[xxx] size appropriately.
560 */
561 struct tcp_skb_cb {
562 union {
563 struct inet_skb_parm h4;
564 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
565 struct inet6_skb_parm h6;
566 #endif
567 } header; /* For incoming frames */
568 __u32 seq; /* Starting sequence number */
569 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
570 __u32 when; /* used to compute rtt's */
571 __u8 flags; /* TCP header flags. */
572
573 /* NOTE: These must match up to the flags byte in a
574 * real TCP header.
575 */
576 #define TCPCB_FLAG_FIN 0x01
577 #define TCPCB_FLAG_SYN 0x02
578 #define TCPCB_FLAG_RST 0x04
579 #define TCPCB_FLAG_PSH 0x08
580 #define TCPCB_FLAG_ACK 0x10
581 #define TCPCB_FLAG_URG 0x20
582 #define TCPCB_FLAG_ECE 0x40
583 #define TCPCB_FLAG_CWR 0x80
584
585 __u8 sacked; /* State flags for SACK/FACK. */
586 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
587 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
588 #define TCPCB_LOST 0x04 /* SKB is lost */
589 #define TCPCB_TAGBITS 0x07 /* All tag bits */
590
591 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
592 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
593
594 __u16 urg_ptr; /* Valid w/URG flags is set. */
595 __u32 ack_seq; /* Sequence number ACK'd */
596 };
597
598 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
599
600 /* Due to TSO, an SKB can be composed of multiple actual
601 * packets. To keep these tracked properly, we use this.
602 */
603 static inline int tcp_skb_pcount(const struct sk_buff *skb)
604 {
605 return skb_shinfo(skb)->gso_segs;
606 }
607
608 /* This is valid iff tcp_skb_pcount() > 1. */
609 static inline int tcp_skb_mss(const struct sk_buff *skb)
610 {
611 return skb_shinfo(skb)->gso_size;
612 }
613
614 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
615 {
616 if (*count) {
617 *count -= decr;
618 if ((int)*count < 0)
619 *count = 0;
620 }
621 }
622
623 static inline void tcp_dec_pcount_approx(__u32 *count,
624 const struct sk_buff *skb)
625 {
626 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
627 }
628
629 /* Events passed to congestion control interface */
630 enum tcp_ca_event {
631 CA_EVENT_TX_START, /* first transmit when no packets in flight */
632 CA_EVENT_CWND_RESTART, /* congestion window restart */
633 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
634 CA_EVENT_FRTO, /* fast recovery timeout */
635 CA_EVENT_LOSS, /* loss timeout */
636 CA_EVENT_FAST_ACK, /* in sequence ack */
637 CA_EVENT_SLOW_ACK, /* other ack */
638 };
639
640 /*
641 * Interface for adding new TCP congestion control handlers
642 */
643 #define TCP_CA_NAME_MAX 16
644 #define TCP_CA_MAX 128
645 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
646
647 #define TCP_CONG_NON_RESTRICTED 0x1
648 #define TCP_CONG_RTT_STAMP 0x2
649
650 struct tcp_congestion_ops {
651 struct list_head list;
652 unsigned long flags;
653
654 /* initialize private data (optional) */
655 void (*init)(struct sock *sk);
656 /* cleanup private data (optional) */
657 void (*release)(struct sock *sk);
658
659 /* return slow start threshold (required) */
660 u32 (*ssthresh)(struct sock *sk);
661 /* lower bound for congestion window (optional) */
662 u32 (*min_cwnd)(const struct sock *sk);
663 /* do new cwnd calculation (required) */
664 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
665 /* call before changing ca_state (optional) */
666 void (*set_state)(struct sock *sk, u8 new_state);
667 /* call when cwnd event occurs (optional) */
668 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
669 /* new value of cwnd after loss (optional) */
670 u32 (*undo_cwnd)(struct sock *sk);
671 /* hook for packet ack accounting (optional) */
672 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
673 /* get info for inet_diag (optional) */
674 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
675
676 char name[TCP_CA_NAME_MAX];
677 struct module *owner;
678 };
679
680 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
681 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
682
683 extern void tcp_init_congestion_control(struct sock *sk);
684 extern void tcp_cleanup_congestion_control(struct sock *sk);
685 extern int tcp_set_default_congestion_control(const char *name);
686 extern void tcp_get_default_congestion_control(char *name);
687 extern void tcp_get_available_congestion_control(char *buf, size_t len);
688 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
689 extern int tcp_set_allowed_congestion_control(char *allowed);
690 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
691 extern void tcp_slow_start(struct tcp_sock *tp);
692
693 extern struct tcp_congestion_ops tcp_init_congestion_ops;
694 extern u32 tcp_reno_ssthresh(struct sock *sk);
695 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
696 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
697 extern struct tcp_congestion_ops tcp_reno;
698
699 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
700 {
701 struct inet_connection_sock *icsk = inet_csk(sk);
702
703 if (icsk->icsk_ca_ops->set_state)
704 icsk->icsk_ca_ops->set_state(sk, ca_state);
705 icsk->icsk_ca_state = ca_state;
706 }
707
708 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
709 {
710 const struct inet_connection_sock *icsk = inet_csk(sk);
711
712 if (icsk->icsk_ca_ops->cwnd_event)
713 icsk->icsk_ca_ops->cwnd_event(sk, event);
714 }
715
716 /* These functions determine how the current flow behaves in respect of SACK
717 * handling. SACK is negotiated with the peer, and therefore it can vary
718 * between different flows.
719 *
720 * tcp_is_sack - SACK enabled
721 * tcp_is_reno - No SACK
722 * tcp_is_fack - FACK enabled, implies SACK enabled
723 */
724 static inline int tcp_is_sack(const struct tcp_sock *tp)
725 {
726 return tp->rx_opt.sack_ok;
727 }
728
729 static inline int tcp_is_reno(const struct tcp_sock *tp)
730 {
731 return !tcp_is_sack(tp);
732 }
733
734 static inline int tcp_is_fack(const struct tcp_sock *tp)
735 {
736 return tp->rx_opt.sack_ok & 2;
737 }
738
739 static inline void tcp_enable_fack(struct tcp_sock *tp)
740 {
741 tp->rx_opt.sack_ok |= 2;
742 }
743
744 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
745 {
746 return tp->sacked_out + tp->lost_out;
747 }
748
749 /* This determines how many packets are "in the network" to the best
750 * of our knowledge. In many cases it is conservative, but where
751 * detailed information is available from the receiver (via SACK
752 * blocks etc.) we can make more aggressive calculations.
753 *
754 * Use this for decisions involving congestion control, use just
755 * tp->packets_out to determine if the send queue is empty or not.
756 *
757 * Read this equation as:
758 *
759 * "Packets sent once on transmission queue" MINUS
760 * "Packets left network, but not honestly ACKed yet" PLUS
761 * "Packets fast retransmitted"
762 */
763 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
764 {
765 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
766 }
767
768 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
769
770 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
771 * The exception is rate halving phase, when cwnd is decreasing towards
772 * ssthresh.
773 */
774 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
775 {
776 const struct tcp_sock *tp = tcp_sk(sk);
777 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
778 return tp->snd_ssthresh;
779 else
780 return max(tp->snd_ssthresh,
781 ((tp->snd_cwnd >> 1) +
782 (tp->snd_cwnd >> 2)));
783 }
784
785 /* Use define here intentionally to get WARN_ON location shown at the caller */
786 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
787
788 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
789 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
790
791 /* Slow start with delack produces 3 packets of burst, so that
792 * it is safe "de facto". This will be the default - same as
793 * the default reordering threshold - but if reordering increases,
794 * we must be able to allow cwnd to burst at least this much in order
795 * to not pull it back when holes are filled.
796 */
797 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
798 {
799 return tp->reordering;
800 }
801
802 /* Returns end sequence number of the receiver's advertised window */
803 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
804 {
805 return tp->snd_una + tp->snd_wnd;
806 }
807 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
808
809 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
810 const struct sk_buff *skb)
811 {
812 if (skb->len < mss)
813 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
814 }
815
816 static inline void tcp_check_probe_timer(struct sock *sk)
817 {
818 struct tcp_sock *tp = tcp_sk(sk);
819 const struct inet_connection_sock *icsk = inet_csk(sk);
820
821 if (!tp->packets_out && !icsk->icsk_pending)
822 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
823 icsk->icsk_rto, TCP_RTO_MAX);
824 }
825
826 static inline void tcp_push_pending_frames(struct sock *sk)
827 {
828 struct tcp_sock *tp = tcp_sk(sk);
829
830 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
831 }
832
833 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
834 {
835 tp->snd_wl1 = seq;
836 }
837
838 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
839 {
840 tp->snd_wl1 = seq;
841 }
842
843 /*
844 * Calculate(/check) TCP checksum
845 */
846 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
847 __be32 daddr, __wsum base)
848 {
849 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
850 }
851
852 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
853 {
854 return __skb_checksum_complete(skb);
855 }
856
857 static inline int tcp_checksum_complete(struct sk_buff *skb)
858 {
859 return !skb_csum_unnecessary(skb) &&
860 __tcp_checksum_complete(skb);
861 }
862
863 /* Prequeue for VJ style copy to user, combined with checksumming. */
864
865 static inline void tcp_prequeue_init(struct tcp_sock *tp)
866 {
867 tp->ucopy.task = NULL;
868 tp->ucopy.len = 0;
869 tp->ucopy.memory = 0;
870 skb_queue_head_init(&tp->ucopy.prequeue);
871 #ifdef CONFIG_NET_DMA
872 tp->ucopy.dma_chan = NULL;
873 tp->ucopy.wakeup = 0;
874 tp->ucopy.pinned_list = NULL;
875 tp->ucopy.dma_cookie = 0;
876 #endif
877 }
878
879 /* Packet is added to VJ-style prequeue for processing in process
880 * context, if a reader task is waiting. Apparently, this exciting
881 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
882 * failed somewhere. Latency? Burstiness? Well, at least now we will
883 * see, why it failed. 8)8) --ANK
884 *
885 * NOTE: is this not too big to inline?
886 */
887 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
888 {
889 struct tcp_sock *tp = tcp_sk(sk);
890
891 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
892 __skb_queue_tail(&tp->ucopy.prequeue, skb);
893 tp->ucopy.memory += skb->truesize;
894 if (tp->ucopy.memory > sk->sk_rcvbuf) {
895 struct sk_buff *skb1;
896
897 BUG_ON(sock_owned_by_user(sk));
898
899 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
900 sk->sk_backlog_rcv(sk, skb1);
901 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
902 }
903
904 tp->ucopy.memory = 0;
905 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
906 wake_up_interruptible(sk->sk_sleep);
907 if (!inet_csk_ack_scheduled(sk))
908 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
909 (3 * TCP_RTO_MIN) / 4,
910 TCP_RTO_MAX);
911 }
912 return 1;
913 }
914 return 0;
915 }
916
917
918 #undef STATE_TRACE
919
920 #ifdef STATE_TRACE
921 static const char *statename[]={
922 "Unused","Established","Syn Sent","Syn Recv",
923 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
924 "Close Wait","Last ACK","Listen","Closing"
925 };
926 #endif
927 extern void tcp_set_state(struct sock *sk, int state);
928
929 extern void tcp_done(struct sock *sk);
930
931 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
932 {
933 rx_opt->dsack = 0;
934 rx_opt->eff_sacks = 0;
935 rx_opt->num_sacks = 0;
936 }
937
938 /* Determine a window scaling and initial window to offer. */
939 extern void tcp_select_initial_window(int __space, __u32 mss,
940 __u32 *rcv_wnd, __u32 *window_clamp,
941 int wscale_ok, __u8 *rcv_wscale);
942
943 static inline int tcp_win_from_space(int space)
944 {
945 return sysctl_tcp_adv_win_scale<=0 ?
946 (space>>(-sysctl_tcp_adv_win_scale)) :
947 space - (space>>sysctl_tcp_adv_win_scale);
948 }
949
950 /* Note: caller must be prepared to deal with negative returns */
951 static inline int tcp_space(const struct sock *sk)
952 {
953 return tcp_win_from_space(sk->sk_rcvbuf -
954 atomic_read(&sk->sk_rmem_alloc));
955 }
956
957 static inline int tcp_full_space(const struct sock *sk)
958 {
959 return tcp_win_from_space(sk->sk_rcvbuf);
960 }
961
962 static inline void tcp_openreq_init(struct request_sock *req,
963 struct tcp_options_received *rx_opt,
964 struct sk_buff *skb)
965 {
966 struct inet_request_sock *ireq = inet_rsk(req);
967
968 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
969 req->cookie_ts = 0;
970 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
971 req->mss = rx_opt->mss_clamp;
972 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
973 ireq->tstamp_ok = rx_opt->tstamp_ok;
974 ireq->sack_ok = rx_opt->sack_ok;
975 ireq->snd_wscale = rx_opt->snd_wscale;
976 ireq->wscale_ok = rx_opt->wscale_ok;
977 ireq->acked = 0;
978 ireq->ecn_ok = 0;
979 ireq->rmt_port = tcp_hdr(skb)->source;
980 }
981
982 extern void tcp_enter_memory_pressure(void);
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(void)
1032 {
1033 /* See RFC 2012 */
1034 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1035 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1036 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1037 TCP_ADD_STATS_USER(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 tp->retransmit_skb_hint = NULL;
1046 tp->forward_skb_hint = NULL;
1047 }
1048
1049 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1050 {
1051 tcp_clear_retrans_hints_partial(tp);
1052 }
1053
1054 /* MD5 Signature */
1055 struct crypto_hash;
1056
1057 /* - key database */
1058 struct tcp_md5sig_key {
1059 u8 *key;
1060 u8 keylen;
1061 };
1062
1063 struct tcp4_md5sig_key {
1064 struct tcp_md5sig_key base;
1065 __be32 addr;
1066 };
1067
1068 struct tcp6_md5sig_key {
1069 struct tcp_md5sig_key base;
1070 #if 0
1071 u32 scope_id; /* XXX */
1072 #endif
1073 struct in6_addr addr;
1074 };
1075
1076 /* - sock block */
1077 struct tcp_md5sig_info {
1078 struct tcp4_md5sig_key *keys4;
1079 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1080 struct tcp6_md5sig_key *keys6;
1081 u32 entries6;
1082 u32 alloced6;
1083 #endif
1084 u32 entries4;
1085 u32 alloced4;
1086 };
1087
1088 /* - pseudo header */
1089 struct tcp4_pseudohdr {
1090 __be32 saddr;
1091 __be32 daddr;
1092 __u8 pad;
1093 __u8 protocol;
1094 __be16 len;
1095 };
1096
1097 struct tcp6_pseudohdr {
1098 struct in6_addr saddr;
1099 struct in6_addr daddr;
1100 __be32 len;
1101 __be32 protocol; /* including padding */
1102 };
1103
1104 union tcp_md5sum_block {
1105 struct tcp4_pseudohdr ip4;
1106 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1107 struct tcp6_pseudohdr ip6;
1108 #endif
1109 };
1110
1111 /* - pool: digest algorithm, hash description and scratch buffer */
1112 struct tcp_md5sig_pool {
1113 struct hash_desc md5_desc;
1114 union tcp_md5sum_block md5_blk;
1115 };
1116
1117 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1118
1119 /* - functions */
1120 extern int tcp_calc_md5_hash(char *md5_hash,
1121 struct tcp_md5sig_key *key,
1122 int bplen,
1123 struct tcphdr *th,
1124 unsigned int tcplen,
1125 struct tcp_md5sig_pool *hp);
1126
1127 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1128 struct tcp_md5sig_key *key,
1129 struct sock *sk,
1130 struct dst_entry *dst,
1131 struct request_sock *req,
1132 struct tcphdr *th,
1133 unsigned int tcplen);
1134 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1135 struct sock *addr_sk);
1136
1137 extern int tcp_v4_md5_do_add(struct sock *sk,
1138 __be32 addr,
1139 u8 *newkey,
1140 u8 newkeylen);
1141
1142 extern int tcp_v4_md5_do_del(struct sock *sk,
1143 __be32 addr);
1144
1145 #ifdef CONFIG_TCP_MD5SIG
1146 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1147 &(struct tcp_md5sig_key) { \
1148 .key = (twsk)->tw_md5_key, \
1149 .keylen = (twsk)->tw_md5_keylen, \
1150 } : NULL)
1151 #else
1152 #define tcp_twsk_md5_key(twsk) NULL
1153 #endif
1154
1155 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1156 extern void tcp_free_md5sig_pool(void);
1157
1158 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1159 extern void __tcp_put_md5sig_pool(void);
1160
1161 static inline
1162 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1163 {
1164 int cpu = get_cpu();
1165 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1166 if (!ret)
1167 put_cpu();
1168 return ret;
1169 }
1170
1171 static inline void tcp_put_md5sig_pool(void)
1172 {
1173 __tcp_put_md5sig_pool();
1174 put_cpu();
1175 }
1176
1177 /* write queue abstraction */
1178 static inline void tcp_write_queue_purge(struct sock *sk)
1179 {
1180 struct sk_buff *skb;
1181
1182 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1183 sk_wmem_free_skb(sk, skb);
1184 sk_mem_reclaim(sk);
1185 }
1186
1187 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1188 {
1189 struct sk_buff *skb = sk->sk_write_queue.next;
1190 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1191 return NULL;
1192 return skb;
1193 }
1194
1195 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1196 {
1197 struct sk_buff *skb = sk->sk_write_queue.prev;
1198 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1199 return NULL;
1200 return skb;
1201 }
1202
1203 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1204 {
1205 return skb->next;
1206 }
1207
1208 #define tcp_for_write_queue(skb, sk) \
1209 for (skb = (sk)->sk_write_queue.next; \
1210 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1211 skb = skb->next)
1212
1213 #define tcp_for_write_queue_from(skb, sk) \
1214 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1215 skb = skb->next)
1216
1217 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1218 for (tmp = skb->next; \
1219 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1220 skb = tmp, tmp = skb->next)
1221
1222 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1223 {
1224 return sk->sk_send_head;
1225 }
1226
1227 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1228 {
1229 sk->sk_send_head = skb->next;
1230 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1231 sk->sk_send_head = NULL;
1232 }
1233
1234 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1235 {
1236 if (sk->sk_send_head == skb_unlinked)
1237 sk->sk_send_head = NULL;
1238 }
1239
1240 static inline void tcp_init_send_head(struct sock *sk)
1241 {
1242 sk->sk_send_head = NULL;
1243 }
1244
1245 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1246 {
1247 __skb_queue_tail(&sk->sk_write_queue, skb);
1248 }
1249
1250 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1251 {
1252 __tcp_add_write_queue_tail(sk, skb);
1253
1254 /* Queue it, remembering where we must start sending. */
1255 if (sk->sk_send_head == NULL) {
1256 sk->sk_send_head = skb;
1257
1258 if (tcp_sk(sk)->highest_sack == NULL)
1259 tcp_sk(sk)->highest_sack = skb;
1260 }
1261 }
1262
1263 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1264 {
1265 __skb_queue_head(&sk->sk_write_queue, skb);
1266 }
1267
1268 /* Insert buff after skb on the write queue of sk. */
1269 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1270 struct sk_buff *buff,
1271 struct sock *sk)
1272 {
1273 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1274 }
1275
1276 /* Insert skb between prev and next on the write queue of sk. */
1277 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1278 struct sk_buff *skb,
1279 struct sock *sk)
1280 {
1281 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1282
1283 if (sk->sk_send_head == skb)
1284 sk->sk_send_head = new;
1285 }
1286
1287 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1288 {
1289 __skb_unlink(skb, &sk->sk_write_queue);
1290 }
1291
1292 static inline int tcp_skb_is_last(const struct sock *sk,
1293 const struct sk_buff *skb)
1294 {
1295 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1296 }
1297
1298 static inline int tcp_write_queue_empty(struct sock *sk)
1299 {
1300 return skb_queue_empty(&sk->sk_write_queue);
1301 }
1302
1303 /* Start sequence of the highest skb with SACKed bit, valid only if
1304 * sacked > 0 or when the caller has ensured validity by itself.
1305 */
1306 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1307 {
1308 if (!tp->sacked_out)
1309 return tp->snd_una;
1310
1311 if (tp->highest_sack == NULL)
1312 return tp->snd_nxt;
1313
1314 return TCP_SKB_CB(tp->highest_sack)->seq;
1315 }
1316
1317 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1318 {
1319 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1320 tcp_write_queue_next(sk, skb);
1321 }
1322
1323 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1324 {
1325 return tcp_sk(sk)->highest_sack;
1326 }
1327
1328 static inline void tcp_highest_sack_reset(struct sock *sk)
1329 {
1330 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1331 }
1332
1333 /* Called when old skb is about to be deleted (to be combined with new skb) */
1334 static inline void tcp_highest_sack_combine(struct sock *sk,
1335 struct sk_buff *old,
1336 struct sk_buff *new)
1337 {
1338 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1339 tcp_sk(sk)->highest_sack = new;
1340 }
1341
1342 /* /proc */
1343 enum tcp_seq_states {
1344 TCP_SEQ_STATE_LISTENING,
1345 TCP_SEQ_STATE_OPENREQ,
1346 TCP_SEQ_STATE_ESTABLISHED,
1347 TCP_SEQ_STATE_TIME_WAIT,
1348 };
1349
1350 struct tcp_seq_afinfo {
1351 char *name;
1352 sa_family_t family;
1353 struct file_operations seq_fops;
1354 struct seq_operations seq_ops;
1355 };
1356
1357 struct tcp_iter_state {
1358 struct seq_net_private p;
1359 sa_family_t family;
1360 enum tcp_seq_states state;
1361 struct sock *syn_wait_sk;
1362 int bucket, sbucket, num, uid;
1363 };
1364
1365 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1366 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1367
1368 extern struct request_sock_ops tcp_request_sock_ops;
1369 extern struct request_sock_ops tcp6_request_sock_ops;
1370
1371 extern int tcp_v4_destroy_sock(struct sock *sk);
1372
1373 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1374 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1375
1376 #ifdef CONFIG_PROC_FS
1377 extern int tcp4_proc_init(void);
1378 extern void tcp4_proc_exit(void);
1379 #endif
1380
1381 /* TCP af-specific functions */
1382 struct tcp_sock_af_ops {
1383 #ifdef CONFIG_TCP_MD5SIG
1384 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1385 struct sock *addr_sk);
1386 int (*calc_md5_hash) (char *location,
1387 struct tcp_md5sig_key *md5,
1388 struct sock *sk,
1389 struct dst_entry *dst,
1390 struct request_sock *req,
1391 struct tcphdr *th,
1392 unsigned int len);
1393 int (*md5_add) (struct sock *sk,
1394 struct sock *addr_sk,
1395 u8 *newkey,
1396 u8 len);
1397 int (*md5_parse) (struct sock *sk,
1398 char __user *optval,
1399 int optlen);
1400 #endif
1401 };
1402
1403 struct tcp_request_sock_ops {
1404 #ifdef CONFIG_TCP_MD5SIG
1405 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1406 struct request_sock *req);
1407 #endif
1408 };
1409
1410 extern void tcp_v4_init(void);
1411 extern void tcp_init(void);
1412
1413 #endif /* _TCP_H */
kernel-based virtual machine