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Linux 2.6.33-rc2
[pohmelfs.git] / include / net / tcp.h
blob34f5cc24d903332f9c29f2cb0484ade46dad0f54
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 #include <linux/kref.h>
34
35 #include <net/inet_connection_sock.h>
36 #include <net/inet_timewait_sock.h>
37 #include <net/inet_hashtables.h>
38 #include <net/checksum.h>
39 #include <net/request_sock.h>
40 #include <net/sock.h>
41 #include <net/snmp.h>
42 #include <net/ip.h>
43 #include <net/tcp_states.h>
44 #include <net/inet_ecn.h>
45 #include <net/dst.h>
46
47 #include <linux/seq_file.h>
48
49 extern struct inet_hashinfo tcp_hashinfo;
50
51 extern struct percpu_counter tcp_orphan_count;
52 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
53
54 #define MAX_TCP_HEADER (128 + MAX_HEADER)
55 #define MAX_TCP_OPTION_SPACE 40
56
57 /*
58 * Never offer a window over 32767 without using window scaling. Some
59 * poor stacks do signed 16bit maths!
60 */
61 #define MAX_TCP_WINDOW 32767U
62
63 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
64 #define TCP_MIN_MSS 88U
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
143 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
144
145 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
146 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
147 * after this time. It should be equal
148 * (or greater than) TCP_TIMEWAIT_LEN
149 * to provide reliability equal to one
150 * provided by timewait state.
151 */
152 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
153 * timestamps. It must be less than
154 * minimal timewait lifetime.
155 */
156 /*
157 * TCP option
158 */
159
160 #define TCPOPT_NOP 1 /* Padding */
161 #define TCPOPT_EOL 0 /* End of options */
162 #define TCPOPT_MSS 2 /* Segment size negotiating */
163 #define TCPOPT_WINDOW 3 /* Window scaling */
164 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
165 #define TCPOPT_SACK 5 /* SACK Block */
166 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
167 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
168 #define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */
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 #define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */
180 #define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */
181 #define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN)
182 #define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX)
183
184 /* But this is what stacks really send out. */
185 #define TCPOLEN_TSTAMP_ALIGNED 12
186 #define TCPOLEN_WSCALE_ALIGNED 4
187 #define TCPOLEN_SACKPERM_ALIGNED 4
188 #define TCPOLEN_SACK_BASE 2
189 #define TCPOLEN_SACK_BASE_ALIGNED 4
190 #define TCPOLEN_SACK_PERBLOCK 8
191 #define TCPOLEN_MD5SIG_ALIGNED 20
192 #define TCPOLEN_MSS_ALIGNED 4
193
194 /* Flags in tp->nonagle */
195 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
196 #define TCP_NAGLE_CORK 2 /* Socket is corked */
197 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
198
199 extern struct inet_timewait_death_row tcp_death_row;
200
201 /* sysctl variables for tcp */
202 extern int sysctl_tcp_timestamps;
203 extern int sysctl_tcp_window_scaling;
204 extern int sysctl_tcp_sack;
205 extern int sysctl_tcp_fin_timeout;
206 extern int sysctl_tcp_keepalive_time;
207 extern int sysctl_tcp_keepalive_probes;
208 extern int sysctl_tcp_keepalive_intvl;
209 extern int sysctl_tcp_syn_retries;
210 extern int sysctl_tcp_synack_retries;
211 extern int sysctl_tcp_retries1;
212 extern int sysctl_tcp_retries2;
213 extern int sysctl_tcp_orphan_retries;
214 extern int sysctl_tcp_syncookies;
215 extern int sysctl_tcp_retrans_collapse;
216 extern int sysctl_tcp_stdurg;
217 extern int sysctl_tcp_rfc1337;
218 extern int sysctl_tcp_abort_on_overflow;
219 extern int sysctl_tcp_max_orphans;
220 extern int sysctl_tcp_fack;
221 extern int sysctl_tcp_reordering;
222 extern int sysctl_tcp_ecn;
223 extern int sysctl_tcp_dsack;
224 extern int sysctl_tcp_mem[3];
225 extern int sysctl_tcp_wmem[3];
226 extern int sysctl_tcp_rmem[3];
227 extern int sysctl_tcp_app_win;
228 extern int sysctl_tcp_adv_win_scale;
229 extern int sysctl_tcp_tw_reuse;
230 extern int sysctl_tcp_frto;
231 extern int sysctl_tcp_frto_response;
232 extern int sysctl_tcp_low_latency;
233 extern int sysctl_tcp_dma_copybreak;
234 extern int sysctl_tcp_nometrics_save;
235 extern int sysctl_tcp_moderate_rcvbuf;
236 extern int sysctl_tcp_tso_win_divisor;
237 extern int sysctl_tcp_abc;
238 extern int sysctl_tcp_mtu_probing;
239 extern int sysctl_tcp_base_mss;
240 extern int sysctl_tcp_workaround_signed_windows;
241 extern int sysctl_tcp_slow_start_after_idle;
242 extern int sysctl_tcp_max_ssthresh;
243 extern int sysctl_tcp_cookie_size;
244
245 extern atomic_t tcp_memory_allocated;
246 extern struct percpu_counter tcp_sockets_allocated;
247 extern int tcp_memory_pressure;
248
249 /*
250 * The next routines deal with comparing 32 bit unsigned ints
251 * and worry about wraparound (automatic with unsigned arithmetic).
252 */
253
254 static inline int before(__u32 seq1, __u32 seq2)
255 {
256 return (__s32)(seq1-seq2) < 0;
257 }
258 #define after(seq2, seq1) before(seq1, seq2)
259
260 /* is s2<=s1<=s3 ? */
261 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
262 {
263 return seq3 - seq2 >= seq1 - seq2;
264 }
265
266 static inline int tcp_too_many_orphans(struct sock *sk, int num)
267 {
268 return (num > sysctl_tcp_max_orphans) ||
269 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
270 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
271 }
272
273 /* syncookies: remember time of last synqueue overflow */
274 static inline void tcp_synq_overflow(struct sock *sk)
275 {
276 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
277 }
278
279 /* syncookies: no recent synqueue overflow on this listening socket? */
280 static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
281 {
282 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
283 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
284 }
285
286 extern struct proto tcp_prot;
287
288 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
289 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
290 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
291 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
292
293 extern void tcp_v4_err(struct sk_buff *skb, u32);
294
295 extern void tcp_shutdown (struct sock *sk, int how);
296
297 extern int tcp_v4_rcv(struct sk_buff *skb);
298
299 extern int tcp_v4_remember_stamp(struct sock *sk);
300
301 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
302
303 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
304 struct msghdr *msg, size_t size);
305 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
306
307 extern int tcp_ioctl(struct sock *sk,
308 int cmd,
309 unsigned long arg);
310
311 extern int tcp_rcv_state_process(struct sock *sk,
312 struct sk_buff *skb,
313 struct tcphdr *th,
314 unsigned len);
315
316 extern int tcp_rcv_established(struct sock *sk,
317 struct sk_buff *skb,
318 struct tcphdr *th,
319 unsigned len);
320
321 extern void tcp_rcv_space_adjust(struct sock *sk);
322
323 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
324
325 extern int tcp_twsk_unique(struct sock *sk,
326 struct sock *sktw, void *twp);
327
328 extern void tcp_twsk_destructor(struct sock *sk);
329
330 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
331 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
332
333 static inline void tcp_dec_quickack_mode(struct sock *sk,
334 const unsigned int pkts)
335 {
336 struct inet_connection_sock *icsk = inet_csk(sk);
337
338 if (icsk->icsk_ack.quick) {
339 if (pkts >= icsk->icsk_ack.quick) {
340 icsk->icsk_ack.quick = 0;
341 /* Leaving quickack mode we deflate ATO. */
342 icsk->icsk_ack.ato = TCP_ATO_MIN;
343 } else
344 icsk->icsk_ack.quick -= pkts;
345 }
346 }
347
348 extern void tcp_enter_quickack_mode(struct sock *sk);
349
350 #define TCP_ECN_OK 1
351 #define TCP_ECN_QUEUE_CWR 2
352 #define TCP_ECN_DEMAND_CWR 4
353
354 static __inline__ void
355 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
356 {
357 if (sysctl_tcp_ecn && th->ece && th->cwr)
358 inet_rsk(req)->ecn_ok = 1;
359 }
360
361 enum tcp_tw_status {
362 TCP_TW_SUCCESS = 0,
363 TCP_TW_RST = 1,
364 TCP_TW_ACK = 2,
365 TCP_TW_SYN = 3
366 };
367
368
369 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
370 struct sk_buff *skb,
371 const struct tcphdr *th);
372
373 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
374 struct request_sock *req,
375 struct request_sock **prev);
376 extern int tcp_child_process(struct sock *parent,
377 struct sock *child,
378 struct sk_buff *skb);
379 extern int tcp_use_frto(struct sock *sk);
380 extern void tcp_enter_frto(struct sock *sk);
381 extern void tcp_enter_loss(struct sock *sk, int how);
382 extern void tcp_clear_retrans(struct tcp_sock *tp);
383 extern void tcp_update_metrics(struct sock *sk);
384
385 extern void tcp_close(struct sock *sk,
386 long timeout);
387 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
388
389 extern int tcp_getsockopt(struct sock *sk, int level,
390 int optname,
391 char __user *optval,
392 int __user *optlen);
393 extern int tcp_setsockopt(struct sock *sk, int level,
394 int optname, char __user *optval,
395 unsigned int optlen);
396 extern int compat_tcp_getsockopt(struct sock *sk,
397 int level, int optname,
398 char __user *optval, int __user *optlen);
399 extern int compat_tcp_setsockopt(struct sock *sk,
400 int level, int optname,
401 char __user *optval, unsigned int optlen);
402 extern void tcp_set_keepalive(struct sock *sk, int val);
403 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
404 struct msghdr *msg,
405 size_t len, int nonblock,
406 int flags, int *addr_len);
407
408 extern void tcp_parse_options(struct sk_buff *skb,
409 struct tcp_options_received *opt_rx,
410 u8 **hvpp,
411 int estab);
412
413 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
414
415 /*
416 * TCP v4 functions exported for the inet6 API
417 */
418
419 extern void tcp_v4_send_check(struct sock *sk, int len,
420 struct sk_buff *skb);
421
422 extern int tcp_v4_conn_request(struct sock *sk,
423 struct sk_buff *skb);
424
425 extern struct sock * tcp_create_openreq_child(struct sock *sk,
426 struct request_sock *req,
427 struct sk_buff *skb);
428
429 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
430 struct sk_buff *skb,
431 struct request_sock *req,
432 struct dst_entry *dst);
433
434 extern int tcp_v4_do_rcv(struct sock *sk,
435 struct sk_buff *skb);
436
437 extern int tcp_v4_connect(struct sock *sk,
438 struct sockaddr *uaddr,
439 int addr_len);
440
441 extern int tcp_connect(struct sock *sk);
442
443 extern struct sk_buff * tcp_make_synack(struct sock *sk,
444 struct dst_entry *dst,
445 struct request_sock *req,
446 struct request_values *rvp);
447
448 extern int tcp_disconnect(struct sock *sk, int flags);
449
450
451 /* From syncookies.c */
452 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
453 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
454 struct ip_options *opt);
455 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
456 __u16 *mss);
457
458 extern __u32 cookie_init_timestamp(struct request_sock *req);
459 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
460
461 /* From net/ipv6/syncookies.c */
462 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
463 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
464 __u16 *mss);
465
466 /* tcp_output.c */
467
468 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
469 int nonagle);
470 extern int tcp_may_send_now(struct sock *sk);
471 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
472 extern void tcp_retransmit_timer(struct sock *sk);
473 extern void tcp_xmit_retransmit_queue(struct sock *);
474 extern void tcp_simple_retransmit(struct sock *);
475 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
476 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
477
478 extern void tcp_send_probe0(struct sock *);
479 extern void tcp_send_partial(struct sock *);
480 extern int tcp_write_wakeup(struct sock *);
481 extern void tcp_send_fin(struct sock *sk);
482 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
483 extern int tcp_send_synack(struct sock *);
484 extern void tcp_push_one(struct sock *, unsigned int mss_now);
485 extern void tcp_send_ack(struct sock *sk);
486 extern void tcp_send_delayed_ack(struct sock *sk);
487
488 /* tcp_input.c */
489 extern void tcp_cwnd_application_limited(struct sock *sk);
490
491 /* tcp_timer.c */
492 extern void tcp_init_xmit_timers(struct sock *);
493 static inline void tcp_clear_xmit_timers(struct sock *sk)
494 {
495 inet_csk_clear_xmit_timers(sk);
496 }
497
498 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
499 extern unsigned int tcp_current_mss(struct sock *sk);
500
501 /* Bound MSS / TSO packet size with the half of the window */
502 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
503 {
504 if (tp->max_window && pktsize > (tp->max_window >> 1))
505 return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
506 else
507 return pktsize;
508 }
509
510 /* tcp.c */
511 extern void tcp_get_info(struct sock *, struct tcp_info *);
512
513 /* Read 'sendfile()'-style from a TCP socket */
514 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
515 unsigned int, size_t);
516 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
517 sk_read_actor_t recv_actor);
518
519 extern void tcp_initialize_rcv_mss(struct sock *sk);
520
521 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
522 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
523 extern void tcp_mtup_init(struct sock *sk);
524
525 static inline void tcp_bound_rto(const struct sock *sk)
526 {
527 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
528 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
529 }
530
531 static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
532 {
533 return (tp->srtt >> 3) + tp->rttvar;
534 }
535
536 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
537 {
538 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
539 ntohl(TCP_FLAG_ACK) |
540 snd_wnd);
541 }
542
543 static inline void tcp_fast_path_on(struct tcp_sock *tp)
544 {
545 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
546 }
547
548 static inline void tcp_fast_path_check(struct sock *sk)
549 {
550 struct tcp_sock *tp = tcp_sk(sk);
551
552 if (skb_queue_empty(&tp->out_of_order_queue) &&
553 tp->rcv_wnd &&
554 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
555 !tp->urg_data)
556 tcp_fast_path_on(tp);
557 }
558
559 /* Compute the actual rto_min value */
560 static inline u32 tcp_rto_min(struct sock *sk)
561 {
562 struct dst_entry *dst = __sk_dst_get(sk);
563 u32 rto_min = TCP_RTO_MIN;
564
565 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
566 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
567 return rto_min;
568 }
569
570 /* Compute the actual receive window we are currently advertising.
571 * Rcv_nxt can be after the window if our peer push more data
572 * than the offered window.
573 */
574 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
575 {
576 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
577
578 if (win < 0)
579 win = 0;
580 return (u32) win;
581 }
582
583 /* Choose a new window, without checks for shrinking, and without
584 * scaling applied to the result. The caller does these things
585 * if necessary. This is a "raw" window selection.
586 */
587 extern u32 __tcp_select_window(struct sock *sk);
588
589 /* TCP timestamps are only 32-bits, this causes a slight
590 * complication on 64-bit systems since we store a snapshot
591 * of jiffies in the buffer control blocks below. We decided
592 * to use only the low 32-bits of jiffies and hide the ugly
593 * casts with the following macro.
594 */
595 #define tcp_time_stamp ((__u32)(jiffies))
596
597 /* This is what the send packet queuing engine uses to pass
598 * TCP per-packet control information to the transmission
599 * code. We also store the host-order sequence numbers in
600 * here too. This is 36 bytes on 32-bit architectures,
601 * 40 bytes on 64-bit machines, if this grows please adjust
602 * skbuff.h:skbuff->cb[xxx] size appropriately.
603 */
604 struct tcp_skb_cb {
605 union {
606 struct inet_skb_parm h4;
607 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
608 struct inet6_skb_parm h6;
609 #endif
610 } header; /* For incoming frames */
611 __u32 seq; /* Starting sequence number */
612 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
613 __u32 when; /* used to compute rtt's */
614 __u8 flags; /* TCP header flags. */
615
616 /* NOTE: These must match up to the flags byte in a
617 * real TCP header.
618 */
619 #define TCPCB_FLAG_FIN 0x01
620 #define TCPCB_FLAG_SYN 0x02
621 #define TCPCB_FLAG_RST 0x04
622 #define TCPCB_FLAG_PSH 0x08
623 #define TCPCB_FLAG_ACK 0x10
624 #define TCPCB_FLAG_URG 0x20
625 #define TCPCB_FLAG_ECE 0x40
626 #define TCPCB_FLAG_CWR 0x80
627
628 __u8 sacked; /* State flags for SACK/FACK. */
629 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
630 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
631 #define TCPCB_LOST 0x04 /* SKB is lost */
632 #define TCPCB_TAGBITS 0x07 /* All tag bits */
633
634 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
635 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
636
637 __u32 ack_seq; /* Sequence number ACK'd */
638 };
639
640 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
641
642 /* Due to TSO, an SKB can be composed of multiple actual
643 * packets. To keep these tracked properly, we use this.
644 */
645 static inline int tcp_skb_pcount(const struct sk_buff *skb)
646 {
647 return skb_shinfo(skb)->gso_segs;
648 }
649
650 /* This is valid iff tcp_skb_pcount() > 1. */
651 static inline int tcp_skb_mss(const struct sk_buff *skb)
652 {
653 return skb_shinfo(skb)->gso_size;
654 }
655
656 /* Events passed to congestion control interface */
657 enum tcp_ca_event {
658 CA_EVENT_TX_START, /* first transmit when no packets in flight */
659 CA_EVENT_CWND_RESTART, /* congestion window restart */
660 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
661 CA_EVENT_FRTO, /* fast recovery timeout */
662 CA_EVENT_LOSS, /* loss timeout */
663 CA_EVENT_FAST_ACK, /* in sequence ack */
664 CA_EVENT_SLOW_ACK, /* other ack */
665 };
666
667 /*
668 * Interface for adding new TCP congestion control handlers
669 */
670 #define TCP_CA_NAME_MAX 16
671 #define TCP_CA_MAX 128
672 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
673
674 #define TCP_CONG_NON_RESTRICTED 0x1
675 #define TCP_CONG_RTT_STAMP 0x2
676
677 struct tcp_congestion_ops {
678 struct list_head list;
679 unsigned long flags;
680
681 /* initialize private data (optional) */
682 void (*init)(struct sock *sk);
683 /* cleanup private data (optional) */
684 void (*release)(struct sock *sk);
685
686 /* return slow start threshold (required) */
687 u32 (*ssthresh)(struct sock *sk);
688 /* lower bound for congestion window (optional) */
689 u32 (*min_cwnd)(const struct sock *sk);
690 /* do new cwnd calculation (required) */
691 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
692 /* call before changing ca_state (optional) */
693 void (*set_state)(struct sock *sk, u8 new_state);
694 /* call when cwnd event occurs (optional) */
695 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
696 /* new value of cwnd after loss (optional) */
697 u32 (*undo_cwnd)(struct sock *sk);
698 /* hook for packet ack accounting (optional) */
699 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
700 /* get info for inet_diag (optional) */
701 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
702
703 char name[TCP_CA_NAME_MAX];
704 struct module *owner;
705 };
706
707 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
708 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
709
710 extern void tcp_init_congestion_control(struct sock *sk);
711 extern void tcp_cleanup_congestion_control(struct sock *sk);
712 extern int tcp_set_default_congestion_control(const char *name);
713 extern void tcp_get_default_congestion_control(char *name);
714 extern void tcp_get_available_congestion_control(char *buf, size_t len);
715 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
716 extern int tcp_set_allowed_congestion_control(char *allowed);
717 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
718 extern void tcp_slow_start(struct tcp_sock *tp);
719 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
720
721 extern struct tcp_congestion_ops tcp_init_congestion_ops;
722 extern u32 tcp_reno_ssthresh(struct sock *sk);
723 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
724 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
725 extern struct tcp_congestion_ops tcp_reno;
726
727 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
728 {
729 struct inet_connection_sock *icsk = inet_csk(sk);
730
731 if (icsk->icsk_ca_ops->set_state)
732 icsk->icsk_ca_ops->set_state(sk, ca_state);
733 icsk->icsk_ca_state = ca_state;
734 }
735
736 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
737 {
738 const struct inet_connection_sock *icsk = inet_csk(sk);
739
740 if (icsk->icsk_ca_ops->cwnd_event)
741 icsk->icsk_ca_ops->cwnd_event(sk, event);
742 }
743
744 /* These functions determine how the current flow behaves in respect of SACK
745 * handling. SACK is negotiated with the peer, and therefore it can vary
746 * between different flows.
747 *
748 * tcp_is_sack - SACK enabled
749 * tcp_is_reno - No SACK
750 * tcp_is_fack - FACK enabled, implies SACK enabled
751 */
752 static inline int tcp_is_sack(const struct tcp_sock *tp)
753 {
754 return tp->rx_opt.sack_ok;
755 }
756
757 static inline int tcp_is_reno(const struct tcp_sock *tp)
758 {
759 return !tcp_is_sack(tp);
760 }
761
762 static inline int tcp_is_fack(const struct tcp_sock *tp)
763 {
764 return tp->rx_opt.sack_ok & 2;
765 }
766
767 static inline void tcp_enable_fack(struct tcp_sock *tp)
768 {
769 tp->rx_opt.sack_ok |= 2;
770 }
771
772 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
773 {
774 return tp->sacked_out + tp->lost_out;
775 }
776
777 /* This determines how many packets are "in the network" to the best
778 * of our knowledge. In many cases it is conservative, but where
779 * detailed information is available from the receiver (via SACK
780 * blocks etc.) we can make more aggressive calculations.
781 *
782 * Use this for decisions involving congestion control, use just
783 * tp->packets_out to determine if the send queue is empty or not.
784 *
785 * Read this equation as:
786 *
787 * "Packets sent once on transmission queue" MINUS
788 * "Packets left network, but not honestly ACKed yet" PLUS
789 * "Packets fast retransmitted"
790 */
791 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
792 {
793 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
794 }
795
796 #define TCP_INFINITE_SSTHRESH 0x7fffffff
797
798 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
799 {
800 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
801 }
802
803 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
804 * The exception is rate halving phase, when cwnd is decreasing towards
805 * ssthresh.
806 */
807 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
808 {
809 const struct tcp_sock *tp = tcp_sk(sk);
810 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
811 return tp->snd_ssthresh;
812 else
813 return max(tp->snd_ssthresh,
814 ((tp->snd_cwnd >> 1) +
815 (tp->snd_cwnd >> 2)));
816 }
817
818 /* Use define here intentionally to get WARN_ON location shown at the caller */
819 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
820
821 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
822 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
823
824 /* Slow start with delack produces 3 packets of burst, so that
825 * it is safe "de facto". This will be the default - same as
826 * the default reordering threshold - but if reordering increases,
827 * we must be able to allow cwnd to burst at least this much in order
828 * to not pull it back when holes are filled.
829 */
830 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
831 {
832 return tp->reordering;
833 }
834
835 /* Returns end sequence number of the receiver's advertised window */
836 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
837 {
838 return tp->snd_una + tp->snd_wnd;
839 }
840 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
841
842 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
843 const struct sk_buff *skb)
844 {
845 if (skb->len < mss)
846 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
847 }
848
849 static inline void tcp_check_probe_timer(struct sock *sk)
850 {
851 struct tcp_sock *tp = tcp_sk(sk);
852 const struct inet_connection_sock *icsk = inet_csk(sk);
853
854 if (!tp->packets_out && !icsk->icsk_pending)
855 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
856 icsk->icsk_rto, TCP_RTO_MAX);
857 }
858
859 static inline void tcp_push_pending_frames(struct sock *sk)
860 {
861 struct tcp_sock *tp = tcp_sk(sk);
862
863 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
864 }
865
866 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
867 {
868 tp->snd_wl1 = seq;
869 }
870
871 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
872 {
873 tp->snd_wl1 = seq;
874 }
875
876 /*
877 * Calculate(/check) TCP checksum
878 */
879 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
880 __be32 daddr, __wsum base)
881 {
882 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
883 }
884
885 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
886 {
887 return __skb_checksum_complete(skb);
888 }
889
890 static inline int tcp_checksum_complete(struct sk_buff *skb)
891 {
892 return !skb_csum_unnecessary(skb) &&
893 __tcp_checksum_complete(skb);
894 }
895
896 /* Prequeue for VJ style copy to user, combined with checksumming. */
897
898 static inline void tcp_prequeue_init(struct tcp_sock *tp)
899 {
900 tp->ucopy.task = NULL;
901 tp->ucopy.len = 0;
902 tp->ucopy.memory = 0;
903 skb_queue_head_init(&tp->ucopy.prequeue);
904 #ifdef CONFIG_NET_DMA
905 tp->ucopy.dma_chan = NULL;
906 tp->ucopy.wakeup = 0;
907 tp->ucopy.pinned_list = NULL;
908 tp->ucopy.dma_cookie = 0;
909 #endif
910 }
911
912 /* Packet is added to VJ-style prequeue for processing in process
913 * context, if a reader task is waiting. Apparently, this exciting
914 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
915 * failed somewhere. Latency? Burstiness? Well, at least now we will
916 * see, why it failed. 8)8) --ANK
917 *
918 * NOTE: is this not too big to inline?
919 */
920 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
921 {
922 struct tcp_sock *tp = tcp_sk(sk);
923
924 if (sysctl_tcp_low_latency || !tp->ucopy.task)
925 return 0;
926
927 __skb_queue_tail(&tp->ucopy.prequeue, skb);
928 tp->ucopy.memory += skb->truesize;
929 if (tp->ucopy.memory > sk->sk_rcvbuf) {
930 struct sk_buff *skb1;
931
932 BUG_ON(sock_owned_by_user(sk));
933
934 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
935 sk_backlog_rcv(sk, skb1);
936 NET_INC_STATS_BH(sock_net(sk),
937 LINUX_MIB_TCPPREQUEUEDROPPED);
938 }
939
940 tp->ucopy.memory = 0;
941 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
942 wake_up_interruptible_poll(sk->sk_sleep,
943 POLLIN | POLLRDNORM | POLLRDBAND);
944 if (!inet_csk_ack_scheduled(sk))
945 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
946 (3 * tcp_rto_min(sk)) / 4,
947 TCP_RTO_MAX);
948 }
949 return 1;
950 }
951
952
953 #undef STATE_TRACE
954
955 #ifdef STATE_TRACE
956 static const char *statename[]={
957 "Unused","Established","Syn Sent","Syn Recv",
958 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
959 "Close Wait","Last ACK","Listen","Closing"
960 };
961 #endif
962 extern void tcp_set_state(struct sock *sk, int state);
963
964 extern void tcp_done(struct sock *sk);
965
966 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
967 {
968 rx_opt->dsack = 0;
969 rx_opt->num_sacks = 0;
970 }
971
972 /* Determine a window scaling and initial window to offer. */
973 extern void tcp_select_initial_window(int __space, __u32 mss,
974 __u32 *rcv_wnd, __u32 *window_clamp,
975 int wscale_ok, __u8 *rcv_wscale);
976
977 static inline int tcp_win_from_space(int space)
978 {
979 return sysctl_tcp_adv_win_scale<=0 ?
980 (space>>(-sysctl_tcp_adv_win_scale)) :
981 space - (space>>sysctl_tcp_adv_win_scale);
982 }
983
984 /* Note: caller must be prepared to deal with negative returns */
985 static inline int tcp_space(const struct sock *sk)
986 {
987 return tcp_win_from_space(sk->sk_rcvbuf -
988 atomic_read(&sk->sk_rmem_alloc));
989 }
990
991 static inline int tcp_full_space(const struct sock *sk)
992 {
993 return tcp_win_from_space(sk->sk_rcvbuf);
994 }
995
996 static inline void tcp_openreq_init(struct request_sock *req,
997 struct tcp_options_received *rx_opt,
998 struct sk_buff *skb)
999 {
1000 struct inet_request_sock *ireq = inet_rsk(req);
1001
1002 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
1003 req->cookie_ts = 0;
1004 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1005 req->mss = rx_opt->mss_clamp;
1006 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
1007 ireq->tstamp_ok = rx_opt->tstamp_ok;
1008 ireq->sack_ok = rx_opt->sack_ok;
1009 ireq->snd_wscale = rx_opt->snd_wscale;
1010 ireq->wscale_ok = rx_opt->wscale_ok;
1011 ireq->acked = 0;
1012 ireq->ecn_ok = 0;
1013 ireq->rmt_port = tcp_hdr(skb)->source;
1014 ireq->loc_port = tcp_hdr(skb)->dest;
1015 }
1016
1017 extern void tcp_enter_memory_pressure(struct sock *sk);
1018
1019 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1020 {
1021 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1022 }
1023
1024 static inline int keepalive_time_when(const struct tcp_sock *tp)
1025 {
1026 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1027 }
1028
1029 static inline int keepalive_probes(const struct tcp_sock *tp)
1030 {
1031 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1032 }
1033
1034 static inline int tcp_fin_time(const struct sock *sk)
1035 {
1036 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1037 const int rto = inet_csk(sk)->icsk_rto;
1038
1039 if (fin_timeout < (rto << 2) - (rto >> 1))
1040 fin_timeout = (rto << 2) - (rto >> 1);
1041
1042 return fin_timeout;
1043 }
1044
1045 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1046 int paws_win)
1047 {
1048 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1049 return 1;
1050 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1051 return 1;
1052
1053 return 0;
1054 }
1055
1056 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1057 int rst)
1058 {
1059 if (tcp_paws_check(rx_opt, 0))
1060 return 0;
1061
1062 /* RST segments are not recommended to carry timestamp,
1063 and, if they do, it is recommended to ignore PAWS because
1064 "their cleanup function should take precedence over timestamps."
1065 Certainly, it is mistake. It is necessary to understand the reasons
1066 of this constraint to relax it: if peer reboots, clock may go
1067 out-of-sync and half-open connections will not be reset.
1068 Actually, the problem would be not existing if all
1069 the implementations followed draft about maintaining clock
1070 via reboots. Linux-2.2 DOES NOT!
1071
1072 However, we can relax time bounds for RST segments to MSL.
1073 */
1074 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1075 return 0;
1076 return 1;
1077 }
1078
1079 #define TCP_CHECK_TIMER(sk) do { } while (0)
1080
1081 static inline void tcp_mib_init(struct net *net)
1082 {
1083 /* See RFC 2012 */
1084 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1085 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1086 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1087 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1088 }
1089
1090 /* from STCP */
1091 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1092 {
1093 tp->lost_skb_hint = NULL;
1094 tp->scoreboard_skb_hint = NULL;
1095 }
1096
1097 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1098 {
1099 tcp_clear_retrans_hints_partial(tp);
1100 tp->retransmit_skb_hint = NULL;
1101 }
1102
1103 /* MD5 Signature */
1104 struct crypto_hash;
1105
1106 /* - key database */
1107 struct tcp_md5sig_key {
1108 u8 *key;
1109 u8 keylen;
1110 };
1111
1112 struct tcp4_md5sig_key {
1113 struct tcp_md5sig_key base;
1114 __be32 addr;
1115 };
1116
1117 struct tcp6_md5sig_key {
1118 struct tcp_md5sig_key base;
1119 #if 0
1120 u32 scope_id; /* XXX */
1121 #endif
1122 struct in6_addr addr;
1123 };
1124
1125 /* - sock block */
1126 struct tcp_md5sig_info {
1127 struct tcp4_md5sig_key *keys4;
1128 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1129 struct tcp6_md5sig_key *keys6;
1130 u32 entries6;
1131 u32 alloced6;
1132 #endif
1133 u32 entries4;
1134 u32 alloced4;
1135 };
1136
1137 /* - pseudo header */
1138 struct tcp4_pseudohdr {
1139 __be32 saddr;
1140 __be32 daddr;
1141 __u8 pad;
1142 __u8 protocol;
1143 __be16 len;
1144 };
1145
1146 struct tcp6_pseudohdr {
1147 struct in6_addr saddr;
1148 struct in6_addr daddr;
1149 __be32 len;
1150 __be32 protocol; /* including padding */
1151 };
1152
1153 union tcp_md5sum_block {
1154 struct tcp4_pseudohdr ip4;
1155 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1156 struct tcp6_pseudohdr ip6;
1157 #endif
1158 };
1159
1160 /* - pool: digest algorithm, hash description and scratch buffer */
1161 struct tcp_md5sig_pool {
1162 struct hash_desc md5_desc;
1163 union tcp_md5sum_block md5_blk;
1164 };
1165
1166 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1167
1168 /* - functions */
1169 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1170 struct tcp_md5sig_key *key,
1171 struct sock *sk,
1172 struct request_sock *req,
1173 struct sk_buff *skb);
1174
1175 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1176 struct sock *addr_sk);
1177
1178 extern int tcp_v4_md5_do_add(struct sock *sk,
1179 __be32 addr,
1180 u8 *newkey,
1181 u8 newkeylen);
1182
1183 extern int tcp_v4_md5_do_del(struct sock *sk,
1184 __be32 addr);
1185
1186 #ifdef CONFIG_TCP_MD5SIG
1187 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1188 &(struct tcp_md5sig_key) { \
1189 .key = (twsk)->tw_md5_key, \
1190 .keylen = (twsk)->tw_md5_keylen, \
1191 } : NULL)
1192 #else
1193 #define tcp_twsk_md5_key(twsk) NULL
1194 #endif
1195
1196 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *);
1197 extern void tcp_free_md5sig_pool(void);
1198
1199 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1200 extern void __tcp_put_md5sig_pool(void);
1201 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1202 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1203 unsigned header_len);
1204 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1205 struct tcp_md5sig_key *key);
1206
1207 static inline
1208 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1209 {
1210 int cpu = get_cpu();
1211 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1212 if (!ret)
1213 put_cpu();
1214 return ret;
1215 }
1216
1217 static inline void tcp_put_md5sig_pool(void)
1218 {
1219 __tcp_put_md5sig_pool();
1220 put_cpu();
1221 }
1222
1223 /* write queue abstraction */
1224 static inline void tcp_write_queue_purge(struct sock *sk)
1225 {
1226 struct sk_buff *skb;
1227
1228 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1229 sk_wmem_free_skb(sk, skb);
1230 sk_mem_reclaim(sk);
1231 tcp_clear_all_retrans_hints(tcp_sk(sk));
1232 }
1233
1234 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1235 {
1236 return skb_peek(&sk->sk_write_queue);
1237 }
1238
1239 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1240 {
1241 return skb_peek_tail(&sk->sk_write_queue);
1242 }
1243
1244 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1245 {
1246 return skb_queue_next(&sk->sk_write_queue, skb);
1247 }
1248
1249 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1250 {
1251 return skb_queue_prev(&sk->sk_write_queue, skb);
1252 }
1253
1254 #define tcp_for_write_queue(skb, sk) \
1255 skb_queue_walk(&(sk)->sk_write_queue, skb)
1256
1257 #define tcp_for_write_queue_from(skb, sk) \
1258 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1259
1260 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1261 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1262
1263 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1264 {
1265 return sk->sk_send_head;
1266 }
1267
1268 static inline bool tcp_skb_is_last(const struct sock *sk,
1269 const struct sk_buff *skb)
1270 {
1271 return skb_queue_is_last(&sk->sk_write_queue, skb);
1272 }
1273
1274 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1275 {
1276 if (tcp_skb_is_last(sk, skb))
1277 sk->sk_send_head = NULL;
1278 else
1279 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1280 }
1281
1282 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1283 {
1284 if (sk->sk_send_head == skb_unlinked)
1285 sk->sk_send_head = NULL;
1286 }
1287
1288 static inline void tcp_init_send_head(struct sock *sk)
1289 {
1290 sk->sk_send_head = NULL;
1291 }
1292
1293 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1294 {
1295 __skb_queue_tail(&sk->sk_write_queue, skb);
1296 }
1297
1298 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1299 {
1300 __tcp_add_write_queue_tail(sk, skb);
1301
1302 /* Queue it, remembering where we must start sending. */
1303 if (sk->sk_send_head == NULL) {
1304 sk->sk_send_head = skb;
1305
1306 if (tcp_sk(sk)->highest_sack == NULL)
1307 tcp_sk(sk)->highest_sack = skb;
1308 }
1309 }
1310
1311 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1312 {
1313 __skb_queue_head(&sk->sk_write_queue, skb);
1314 }
1315
1316 /* Insert buff after skb on the write queue of sk. */
1317 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1318 struct sk_buff *buff,
1319 struct sock *sk)
1320 {
1321 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1322 }
1323
1324 /* Insert new before skb on the write queue of sk. */
1325 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1326 struct sk_buff *skb,
1327 struct sock *sk)
1328 {
1329 __skb_queue_before(&sk->sk_write_queue, skb, new);
1330
1331 if (sk->sk_send_head == skb)
1332 sk->sk_send_head = new;
1333 }
1334
1335 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1336 {
1337 __skb_unlink(skb, &sk->sk_write_queue);
1338 }
1339
1340 static inline int tcp_write_queue_empty(struct sock *sk)
1341 {
1342 return skb_queue_empty(&sk->sk_write_queue);
1343 }
1344
1345 /* Start sequence of the highest skb with SACKed bit, valid only if
1346 * sacked > 0 or when the caller has ensured validity by itself.
1347 */
1348 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1349 {
1350 if (!tp->sacked_out)
1351 return tp->snd_una;
1352
1353 if (tp->highest_sack == NULL)
1354 return tp->snd_nxt;
1355
1356 return TCP_SKB_CB(tp->highest_sack)->seq;
1357 }
1358
1359 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1360 {
1361 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1362 tcp_write_queue_next(sk, skb);
1363 }
1364
1365 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1366 {
1367 return tcp_sk(sk)->highest_sack;
1368 }
1369
1370 static inline void tcp_highest_sack_reset(struct sock *sk)
1371 {
1372 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1373 }
1374
1375 /* Called when old skb is about to be deleted (to be combined with new skb) */
1376 static inline void tcp_highest_sack_combine(struct sock *sk,
1377 struct sk_buff *old,
1378 struct sk_buff *new)
1379 {
1380 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1381 tcp_sk(sk)->highest_sack = new;
1382 }
1383
1384 /* /proc */
1385 enum tcp_seq_states {
1386 TCP_SEQ_STATE_LISTENING,
1387 TCP_SEQ_STATE_OPENREQ,
1388 TCP_SEQ_STATE_ESTABLISHED,
1389 TCP_SEQ_STATE_TIME_WAIT,
1390 };
1391
1392 struct tcp_seq_afinfo {
1393 char *name;
1394 sa_family_t family;
1395 struct file_operations seq_fops;
1396 struct seq_operations seq_ops;
1397 };
1398
1399 struct tcp_iter_state {
1400 struct seq_net_private p;
1401 sa_family_t family;
1402 enum tcp_seq_states state;
1403 struct sock *syn_wait_sk;
1404 int bucket, sbucket, num, uid;
1405 };
1406
1407 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1408 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1409
1410 extern struct request_sock_ops tcp_request_sock_ops;
1411 extern struct request_sock_ops tcp6_request_sock_ops;
1412
1413 extern void tcp_v4_destroy_sock(struct sock *sk);
1414
1415 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1416 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1417 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1418 struct sk_buff *skb);
1419 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1420 struct sk_buff *skb);
1421 extern int tcp_gro_complete(struct sk_buff *skb);
1422 extern int tcp4_gro_complete(struct sk_buff *skb);
1423
1424 #ifdef CONFIG_PROC_FS
1425 extern int tcp4_proc_init(void);
1426 extern void tcp4_proc_exit(void);
1427 #endif
1428
1429 /* TCP af-specific functions */
1430 struct tcp_sock_af_ops {
1431 #ifdef CONFIG_TCP_MD5SIG
1432 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1433 struct sock *addr_sk);
1434 int (*calc_md5_hash) (char *location,
1435 struct tcp_md5sig_key *md5,
1436 struct sock *sk,
1437 struct request_sock *req,
1438 struct sk_buff *skb);
1439 int (*md5_add) (struct sock *sk,
1440 struct sock *addr_sk,
1441 u8 *newkey,
1442 u8 len);
1443 int (*md5_parse) (struct sock *sk,
1444 char __user *optval,
1445 int optlen);
1446 #endif
1447 };
1448
1449 struct tcp_request_sock_ops {
1450 #ifdef CONFIG_TCP_MD5SIG
1451 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1452 struct request_sock *req);
1453 int (*calc_md5_hash) (char *location,
1454 struct tcp_md5sig_key *md5,
1455 struct sock *sk,
1456 struct request_sock *req,
1457 struct sk_buff *skb);
1458 #endif
1459 };
1460
1461 /* Using SHA1 for now, define some constants.
1462 */
1463 #define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS)
1464 #define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4)
1465 #define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS)
1466
1467 extern int tcp_cookie_generator(u32 *bakery);
1468
1469 /**
1470 * struct tcp_cookie_values - each socket needs extra space for the
1471 * cookies, together with (optional) space for any SYN data.
1472 *
1473 * A tcp_sock contains a pointer to the current value, and this is
1474 * cloned to the tcp_timewait_sock.
1475 *
1476 * @cookie_pair: variable data from the option exchange.
1477 *
1478 * @cookie_desired: user specified tcpct_cookie_desired. Zero
1479 * indicates default (sysctl_tcp_cookie_size).
1480 * After cookie sent, remembers size of cookie.
1481 * Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX.
1482 *
1483 * @s_data_desired: user specified tcpct_s_data_desired. When the
1484 * constant payload is specified (@s_data_constant),
1485 * holds its length instead.
1486 * Range 0 to TCP_MSS_DESIRED.
1487 *
1488 * @s_data_payload: constant data that is to be included in the
1489 * payload of SYN or SYNACK segments when the
1490 * cookie option is present.
1491 */
1492 struct tcp_cookie_values {
1493 struct kref kref;
1494 u8 cookie_pair[TCP_COOKIE_PAIR_SIZE];
1495 u8 cookie_pair_size;
1496 u8 cookie_desired;
1497 u16 s_data_desired:11,
1498 s_data_constant:1,
1499 s_data_in:1,
1500 s_data_out:1,
1501 s_data_unused:2;
1502 u8 s_data_payload[0];
1503 };
1504
1505 static inline void tcp_cookie_values_release(struct kref *kref)
1506 {
1507 kfree(container_of(kref, struct tcp_cookie_values, kref));
1508 }
1509
1510 /* The length of constant payload data. Note that s_data_desired is
1511 * overloaded, depending on s_data_constant: either the length of constant
1512 * data (returned here) or the limit on variable data.
1513 */
1514 static inline int tcp_s_data_size(const struct tcp_sock *tp)
1515 {
1516 return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant)
1517 ? tp->cookie_values->s_data_desired
1518 : 0;
1519 }
1520
1521 /**
1522 * struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace.
1523 *
1524 * As tcp_request_sock has already been extended in other places, the
1525 * only remaining method is to pass stack values along as function
1526 * parameters. These parameters are not needed after sending SYNACK.
1527 *
1528 * @cookie_bakery: cryptographic secret and message workspace.
1529 *
1530 * @cookie_plus: bytes in authenticator/cookie option, copied from
1531 * struct tcp_options_received (above).
1532 */
1533 struct tcp_extend_values {
1534 struct request_values rv;
1535 u32 cookie_bakery[COOKIE_WORKSPACE_WORDS];
1536 u8 cookie_plus:6,
1537 cookie_out_never:1,
1538 cookie_in_always:1;
1539 };
1540
1541 static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp)
1542 {
1543 return (struct tcp_extend_values *)rvp;
1544 }
1545
1546 extern void tcp_v4_init(void);
1547 extern void tcp_init(void);
1548
1549 #endif /* _TCP_H */