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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
3 | * operating system. INET is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * Definitions for the TCP module. | |
7 | * | |
8 | * Version: @(#)tcp.h 1.0.5 05/23/93 | |
9 | * | |
02c30a84 | 10 | * Authors: Ross Biro |
1da177e4 LT |
11 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
12 | * | |
13 | * This program is free software; you can redistribute it and/or | |
14 | * modify it under the terms of the GNU General Public License | |
15 | * as published by the Free Software Foundation; either version | |
16 | * 2 of the License, or (at your option) any later version. | |
17 | */ | |
18 | #ifndef _TCP_H | |
19 | #define _TCP_H | |
20 | ||
21 | #define TCP_DEBUG 1 | |
22 | #define FASTRETRANS_DEBUG 1 | |
23 | ||
1da177e4 LT |
24 | #include <linux/config.h> |
25 | #include <linux/list.h> | |
26 | #include <linux/tcp.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/cache.h> | |
29 | #include <linux/percpu.h> | |
fb286bb2 | 30 | #include <linux/skbuff.h> |
3f421baa ACM |
31 | |
32 | #include <net/inet_connection_sock.h> | |
295ff7ed | 33 | #include <net/inet_timewait_sock.h> |
77d8bf9c | 34 | #include <net/inet_hashtables.h> |
1da177e4 | 35 | #include <net/checksum.h> |
2e6599cb | 36 | #include <net/request_sock.h> |
1da177e4 LT |
37 | #include <net/sock.h> |
38 | #include <net/snmp.h> | |
39 | #include <net/ip.h> | |
c752f073 ACM |
40 | #include <net/tcp_states.h> |
41 | ||
1da177e4 LT |
42 | #include <linux/seq_file.h> |
43 | ||
6e04e021 | 44 | extern struct inet_hashinfo tcp_hashinfo; |
1da177e4 | 45 | |
1da177e4 | 46 | extern atomic_t tcp_orphan_count; |
1da177e4 | 47 | extern void tcp_time_wait(struct sock *sk, int state, int timeo); |
1da177e4 | 48 | |
1da177e4 LT |
49 | #define MAX_TCP_HEADER (128 + MAX_HEADER) |
50 | ||
51 | /* | |
52 | * Never offer a window over 32767 without using window scaling. Some | |
53 | * poor stacks do signed 16bit maths! | |
54 | */ | |
55 | #define MAX_TCP_WINDOW 32767U | |
56 | ||
57 | /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ | |
58 | #define TCP_MIN_MSS 88U | |
59 | ||
60 | /* Minimal RCV_MSS. */ | |
61 | #define TCP_MIN_RCVMSS 536U | |
62 | ||
63 | /* After receiving this amount of duplicate ACKs fast retransmit starts. */ | |
64 | #define TCP_FASTRETRANS_THRESH 3 | |
65 | ||
66 | /* Maximal reordering. */ | |
67 | #define TCP_MAX_REORDERING 127 | |
68 | ||
69 | /* Maximal number of ACKs sent quickly to accelerate slow-start. */ | |
70 | #define TCP_MAX_QUICKACKS 16U | |
71 | ||
72 | /* urg_data states */ | |
73 | #define TCP_URG_VALID 0x0100 | |
74 | #define TCP_URG_NOTYET 0x0200 | |
75 | #define TCP_URG_READ 0x0400 | |
76 | ||
77 | #define TCP_RETR1 3 /* | |
78 | * This is how many retries it does before it | |
79 | * tries to figure out if the gateway is | |
80 | * down. Minimal RFC value is 3; it corresponds | |
81 | * to ~3sec-8min depending on RTO. | |
82 | */ | |
83 | ||
84 | #define TCP_RETR2 15 /* | |
85 | * This should take at least | |
86 | * 90 minutes to time out. | |
87 | * RFC1122 says that the limit is 100 sec. | |
88 | * 15 is ~13-30min depending on RTO. | |
89 | */ | |
90 | ||
91 | #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a | |
caa20d9a | 92 | * connection: ~180sec is RFC minimum */ |
1da177e4 LT |
93 | |
94 | #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a | |
caa20d9a | 95 | * connection: ~180sec is RFC minimum */ |
1da177e4 LT |
96 | |
97 | ||
98 | #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned | |
99 | * socket. 7 is ~50sec-16min. | |
100 | */ | |
101 | ||
102 | ||
103 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT | |
104 | * state, about 60 seconds */ | |
105 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
106 | /* BSD style FIN_WAIT2 deadlock breaker. | |
107 | * It used to be 3min, new value is 60sec, | |
108 | * to combine FIN-WAIT-2 timeout with | |
109 | * TIME-WAIT timer. | |
110 | */ | |
111 | ||
112 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
113 | #if HZ >= 100 | |
114 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
115 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
116 | #else | |
117 | #define TCP_DELACK_MIN 4U | |
118 | #define TCP_ATO_MIN 4U | |
119 | #endif | |
120 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
121 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
122 | #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ | |
123 | ||
124 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
125 | * for local resources. | |
126 | */ | |
127 | ||
128 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
129 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
130 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
131 | ||
132 | #define MAX_TCP_KEEPIDLE 32767 | |
133 | #define MAX_TCP_KEEPINTVL 32767 | |
134 | #define MAX_TCP_KEEPCNT 127 | |
135 | #define MAX_TCP_SYNCNT 127 | |
136 | ||
137 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
138 | #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ | |
139 | ||
140 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
141 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
142 | * after this time. It should be equal | |
143 | * (or greater than) TCP_TIMEWAIT_LEN | |
144 | * to provide reliability equal to one | |
145 | * provided by timewait state. | |
146 | */ | |
147 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
148 | * timestamps. It must be less than | |
149 | * minimal timewait lifetime. | |
150 | */ | |
1da177e4 LT |
151 | /* |
152 | * TCP option | |
153 | */ | |
154 | ||
155 | #define TCPOPT_NOP 1 /* Padding */ | |
156 | #define TCPOPT_EOL 0 /* End of options */ | |
157 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
158 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
159 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
160 | #define TCPOPT_SACK 5 /* SACK Block */ | |
161 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
162 | ||
163 | /* | |
164 | * TCP option lengths | |
165 | */ | |
166 | ||
167 | #define TCPOLEN_MSS 4 | |
168 | #define TCPOLEN_WINDOW 3 | |
169 | #define TCPOLEN_SACK_PERM 2 | |
170 | #define TCPOLEN_TIMESTAMP 10 | |
171 | ||
172 | /* But this is what stacks really send out. */ | |
173 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
174 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
175 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
176 | #define TCPOLEN_SACK_BASE 2 | |
177 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
178 | #define TCPOLEN_SACK_PERBLOCK 8 | |
179 | ||
1da177e4 LT |
180 | /* Flags in tp->nonagle */ |
181 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
182 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
caa20d9a | 183 | #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ |
1da177e4 | 184 | |
295ff7ed ACM |
185 | extern struct inet_timewait_death_row tcp_death_row; |
186 | ||
1da177e4 | 187 | /* sysctl variables for tcp */ |
1da177e4 LT |
188 | extern int sysctl_tcp_timestamps; |
189 | extern int sysctl_tcp_window_scaling; | |
190 | extern int sysctl_tcp_sack; | |
191 | extern int sysctl_tcp_fin_timeout; | |
1da177e4 LT |
192 | extern int sysctl_tcp_keepalive_time; |
193 | extern int sysctl_tcp_keepalive_probes; | |
194 | extern int sysctl_tcp_keepalive_intvl; | |
195 | extern int sysctl_tcp_syn_retries; | |
196 | extern int sysctl_tcp_synack_retries; | |
197 | extern int sysctl_tcp_retries1; | |
198 | extern int sysctl_tcp_retries2; | |
199 | extern int sysctl_tcp_orphan_retries; | |
200 | extern int sysctl_tcp_syncookies; | |
201 | extern int sysctl_tcp_retrans_collapse; | |
202 | extern int sysctl_tcp_stdurg; | |
203 | extern int sysctl_tcp_rfc1337; | |
204 | extern int sysctl_tcp_abort_on_overflow; | |
205 | extern int sysctl_tcp_max_orphans; | |
1da177e4 LT |
206 | extern int sysctl_tcp_fack; |
207 | extern int sysctl_tcp_reordering; | |
208 | extern int sysctl_tcp_ecn; | |
209 | extern int sysctl_tcp_dsack; | |
210 | extern int sysctl_tcp_mem[3]; | |
211 | extern int sysctl_tcp_wmem[3]; | |
212 | extern int sysctl_tcp_rmem[3]; | |
213 | extern int sysctl_tcp_app_win; | |
214 | extern int sysctl_tcp_adv_win_scale; | |
215 | extern int sysctl_tcp_tw_reuse; | |
216 | extern int sysctl_tcp_frto; | |
217 | extern int sysctl_tcp_low_latency; | |
1da177e4 | 218 | extern int sysctl_tcp_nometrics_save; |
1da177e4 LT |
219 | extern int sysctl_tcp_moderate_rcvbuf; |
220 | extern int sysctl_tcp_tso_win_divisor; | |
9772efb9 | 221 | extern int sysctl_tcp_abc; |
1da177e4 LT |
222 | |
223 | extern atomic_t tcp_memory_allocated; | |
224 | extern atomic_t tcp_sockets_allocated; | |
225 | extern int tcp_memory_pressure; | |
226 | ||
1da177e4 LT |
227 | /* |
228 | * The next routines deal with comparing 32 bit unsigned ints | |
229 | * and worry about wraparound (automatic with unsigned arithmetic). | |
230 | */ | |
231 | ||
232 | static inline int before(__u32 seq1, __u32 seq2) | |
233 | { | |
234 | return (__s32)(seq1-seq2) < 0; | |
235 | } | |
236 | ||
237 | static inline int after(__u32 seq1, __u32 seq2) | |
238 | { | |
239 | return (__s32)(seq2-seq1) < 0; | |
240 | } | |
241 | ||
242 | ||
243 | /* is s2<=s1<=s3 ? */ | |
244 | static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) | |
245 | { | |
246 | return seq3 - seq2 >= seq1 - seq2; | |
247 | } | |
248 | ||
249 | ||
250 | extern struct proto tcp_prot; | |
251 | ||
252 | DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); | |
253 | #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) | |
254 | #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) | |
255 | #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) | |
256 | #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) | |
257 | #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) | |
258 | #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) | |
259 | ||
1da177e4 LT |
260 | extern void tcp_v4_err(struct sk_buff *skb, u32); |
261 | ||
262 | extern void tcp_shutdown (struct sock *sk, int how); | |
263 | ||
264 | extern int tcp_v4_rcv(struct sk_buff *skb); | |
265 | ||
266 | extern int tcp_v4_remember_stamp(struct sock *sk); | |
267 | ||
8feaf0c0 | 268 | extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); |
1da177e4 LT |
269 | |
270 | extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, | |
271 | struct msghdr *msg, size_t size); | |
272 | extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); | |
273 | ||
274 | extern int tcp_ioctl(struct sock *sk, | |
275 | int cmd, | |
276 | unsigned long arg); | |
277 | ||
278 | extern int tcp_rcv_state_process(struct sock *sk, | |
279 | struct sk_buff *skb, | |
280 | struct tcphdr *th, | |
281 | unsigned len); | |
282 | ||
283 | extern int tcp_rcv_established(struct sock *sk, | |
284 | struct sk_buff *skb, | |
285 | struct tcphdr *th, | |
286 | unsigned len); | |
287 | ||
288 | extern void tcp_rcv_space_adjust(struct sock *sk); | |
289 | ||
6d6ee43e ACM |
290 | extern int tcp_twsk_unique(struct sock *sk, |
291 | struct sock *sktw, void *twp); | |
292 | ||
463c84b9 ACM |
293 | static inline void tcp_dec_quickack_mode(struct sock *sk, |
294 | const unsigned int pkts) | |
1da177e4 | 295 | { |
463c84b9 | 296 | struct inet_connection_sock *icsk = inet_csk(sk); |
fc6415bc | 297 | |
463c84b9 ACM |
298 | if (icsk->icsk_ack.quick) { |
299 | if (pkts >= icsk->icsk_ack.quick) { | |
300 | icsk->icsk_ack.quick = 0; | |
fc6415bc | 301 | /* Leaving quickack mode we deflate ATO. */ |
463c84b9 | 302 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
fc6415bc | 303 | } else |
463c84b9 | 304 | icsk->icsk_ack.quick -= pkts; |
1da177e4 LT |
305 | } |
306 | } | |
307 | ||
463c84b9 | 308 | extern void tcp_enter_quickack_mode(struct sock *sk); |
1da177e4 | 309 | |
1da177e4 LT |
310 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
311 | { | |
312 | rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
313 | } | |
314 | ||
315 | enum tcp_tw_status | |
316 | { | |
317 | TCP_TW_SUCCESS = 0, | |
318 | TCP_TW_RST = 1, | |
319 | TCP_TW_ACK = 2, | |
320 | TCP_TW_SYN = 3 | |
321 | }; | |
322 | ||
323 | ||
8feaf0c0 | 324 | extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, |
1da177e4 | 325 | struct sk_buff *skb, |
8feaf0c0 | 326 | const struct tcphdr *th); |
1da177e4 LT |
327 | |
328 | extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, | |
60236fdd ACM |
329 | struct request_sock *req, |
330 | struct request_sock **prev); | |
1da177e4 LT |
331 | extern int tcp_child_process(struct sock *parent, |
332 | struct sock *child, | |
333 | struct sk_buff *skb); | |
334 | extern void tcp_enter_frto(struct sock *sk); | |
335 | extern void tcp_enter_loss(struct sock *sk, int how); | |
336 | extern void tcp_clear_retrans(struct tcp_sock *tp); | |
337 | extern void tcp_update_metrics(struct sock *sk); | |
338 | ||
339 | extern void tcp_close(struct sock *sk, | |
340 | long timeout); | |
1da177e4 LT |
341 | extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); |
342 | ||
343 | extern int tcp_getsockopt(struct sock *sk, int level, | |
344 | int optname, | |
345 | char __user *optval, | |
346 | int __user *optlen); | |
347 | extern int tcp_setsockopt(struct sock *sk, int level, | |
348 | int optname, char __user *optval, | |
349 | int optlen); | |
350 | extern void tcp_set_keepalive(struct sock *sk, int val); | |
351 | extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, | |
352 | struct msghdr *msg, | |
353 | size_t len, int nonblock, | |
354 | int flags, int *addr_len); | |
355 | ||
1da177e4 LT |
356 | extern void tcp_parse_options(struct sk_buff *skb, |
357 | struct tcp_options_received *opt_rx, | |
358 | int estab); | |
359 | ||
360 | /* | |
361 | * TCP v4 functions exported for the inet6 API | |
362 | */ | |
363 | ||
8292a17a | 364 | extern void tcp_v4_send_check(struct sock *sk, int len, |
1da177e4 LT |
365 | struct sk_buff *skb); |
366 | ||
367 | extern int tcp_v4_conn_request(struct sock *sk, | |
368 | struct sk_buff *skb); | |
369 | ||
370 | extern struct sock * tcp_create_openreq_child(struct sock *sk, | |
60236fdd | 371 | struct request_sock *req, |
1da177e4 LT |
372 | struct sk_buff *skb); |
373 | ||
374 | extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, | |
375 | struct sk_buff *skb, | |
60236fdd | 376 | struct request_sock *req, |
1da177e4 LT |
377 | struct dst_entry *dst); |
378 | ||
379 | extern int tcp_v4_do_rcv(struct sock *sk, | |
380 | struct sk_buff *skb); | |
381 | ||
382 | extern int tcp_v4_connect(struct sock *sk, | |
383 | struct sockaddr *uaddr, | |
384 | int addr_len); | |
385 | ||
386 | extern int tcp_connect(struct sock *sk); | |
387 | ||
388 | extern struct sk_buff * tcp_make_synack(struct sock *sk, | |
389 | struct dst_entry *dst, | |
60236fdd | 390 | struct request_sock *req); |
1da177e4 LT |
391 | |
392 | extern int tcp_disconnect(struct sock *sk, int flags); | |
393 | ||
394 | extern void tcp_unhash(struct sock *sk); | |
395 | ||
396 | extern int tcp_v4_hash_connecting(struct sock *sk); | |
397 | ||
398 | ||
399 | /* From syncookies.c */ | |
400 | extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, | |
401 | struct ip_options *opt); | |
402 | extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, | |
403 | __u16 *mss); | |
404 | ||
405 | /* tcp_output.c */ | |
406 | ||
f6302d1d | 407 | extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, |
a2e2a59c | 408 | unsigned int cur_mss, int nonagle); |
f6302d1d | 409 | extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); |
1da177e4 LT |
410 | extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); |
411 | extern void tcp_xmit_retransmit_queue(struct sock *); | |
412 | extern void tcp_simple_retransmit(struct sock *); | |
413 | extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
6475be16 | 414 | extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); |
1da177e4 LT |
415 | |
416 | extern void tcp_send_probe0(struct sock *); | |
417 | extern void tcp_send_partial(struct sock *); | |
418 | extern int tcp_write_wakeup(struct sock *); | |
419 | extern void tcp_send_fin(struct sock *sk); | |
dd0fc66f | 420 | extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); |
1da177e4 | 421 | extern int tcp_send_synack(struct sock *); |
c1b4a7e6 | 422 | extern void tcp_push_one(struct sock *, unsigned int mss_now); |
1da177e4 LT |
423 | extern void tcp_send_ack(struct sock *sk); |
424 | extern void tcp_send_delayed_ack(struct sock *sk); | |
425 | ||
a762a980 DM |
426 | /* tcp_input.c */ |
427 | extern void tcp_cwnd_application_limited(struct sock *sk); | |
428 | ||
1da177e4 LT |
429 | /* tcp_timer.c */ |
430 | extern void tcp_init_xmit_timers(struct sock *); | |
463c84b9 ACM |
431 | static inline void tcp_clear_xmit_timers(struct sock *sk) |
432 | { | |
433 | inet_csk_clear_xmit_timers(sk); | |
434 | } | |
1da177e4 | 435 | |
1da177e4 LT |
436 | extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); |
437 | extern unsigned int tcp_current_mss(struct sock *sk, int large); | |
438 | ||
17b085ea | 439 | /* tcp.c */ |
1da177e4 LT |
440 | extern void tcp_get_info(struct sock *, struct tcp_info *); |
441 | ||
442 | /* Read 'sendfile()'-style from a TCP socket */ | |
443 | typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, | |
444 | unsigned int, size_t); | |
445 | extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
446 | sk_read_actor_t recv_actor); | |
447 | ||
1da177e4 LT |
448 | /* Initialize RCV_MSS value. |
449 | * RCV_MSS is an our guess about MSS used by the peer. | |
450 | * We haven't any direct information about the MSS. | |
451 | * It's better to underestimate the RCV_MSS rather than overestimate. | |
452 | * Overestimations make us ACKing less frequently than needed. | |
453 | * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). | |
454 | */ | |
455 | ||
456 | static inline void tcp_initialize_rcv_mss(struct sock *sk) | |
457 | { | |
458 | struct tcp_sock *tp = tcp_sk(sk); | |
c1b4a7e6 | 459 | unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); |
1da177e4 LT |
460 | |
461 | hint = min(hint, tp->rcv_wnd/2); | |
462 | hint = min(hint, TCP_MIN_RCVMSS); | |
463 | hint = max(hint, TCP_MIN_MSS); | |
464 | ||
463c84b9 | 465 | inet_csk(sk)->icsk_ack.rcv_mss = hint; |
1da177e4 LT |
466 | } |
467 | ||
468 | static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) | |
469 | { | |
470 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
471 | ntohl(TCP_FLAG_ACK) | | |
472 | snd_wnd); | |
473 | } | |
474 | ||
475 | static __inline__ void tcp_fast_path_on(struct tcp_sock *tp) | |
476 | { | |
477 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
478 | } | |
479 | ||
480 | static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) | |
481 | { | |
b03efcfb | 482 | if (skb_queue_empty(&tp->out_of_order_queue) && |
1da177e4 LT |
483 | tp->rcv_wnd && |
484 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
485 | !tp->urg_data) | |
486 | tcp_fast_path_on(tp); | |
487 | } | |
488 | ||
489 | /* Compute the actual receive window we are currently advertising. | |
490 | * Rcv_nxt can be after the window if our peer push more data | |
491 | * than the offered window. | |
492 | */ | |
493 | static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) | |
494 | { | |
495 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
496 | ||
497 | if (win < 0) | |
498 | win = 0; | |
499 | return (u32) win; | |
500 | } | |
501 | ||
502 | /* Choose a new window, without checks for shrinking, and without | |
503 | * scaling applied to the result. The caller does these things | |
504 | * if necessary. This is a "raw" window selection. | |
505 | */ | |
506 | extern u32 __tcp_select_window(struct sock *sk); | |
507 | ||
508 | /* TCP timestamps are only 32-bits, this causes a slight | |
509 | * complication on 64-bit systems since we store a snapshot | |
31f34269 SH |
510 | * of jiffies in the buffer control blocks below. We decided |
511 | * to use only the low 32-bits of jiffies and hide the ugly | |
1da177e4 LT |
512 | * casts with the following macro. |
513 | */ | |
514 | #define tcp_time_stamp ((__u32)(jiffies)) | |
515 | ||
caa20d9a | 516 | /* This is what the send packet queuing engine uses to pass |
1da177e4 LT |
517 | * TCP per-packet control information to the transmission |
518 | * code. We also store the host-order sequence numbers in | |
519 | * here too. This is 36 bytes on 32-bit architectures, | |
520 | * 40 bytes on 64-bit machines, if this grows please adjust | |
521 | * skbuff.h:skbuff->cb[xxx] size appropriately. | |
522 | */ | |
523 | struct tcp_skb_cb { | |
524 | union { | |
525 | struct inet_skb_parm h4; | |
526 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
527 | struct inet6_skb_parm h6; | |
528 | #endif | |
529 | } header; /* For incoming frames */ | |
530 | __u32 seq; /* Starting sequence number */ | |
531 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
532 | __u32 when; /* used to compute rtt's */ | |
533 | __u8 flags; /* TCP header flags. */ | |
534 | ||
535 | /* NOTE: These must match up to the flags byte in a | |
536 | * real TCP header. | |
537 | */ | |
538 | #define TCPCB_FLAG_FIN 0x01 | |
539 | #define TCPCB_FLAG_SYN 0x02 | |
540 | #define TCPCB_FLAG_RST 0x04 | |
541 | #define TCPCB_FLAG_PSH 0x08 | |
542 | #define TCPCB_FLAG_ACK 0x10 | |
543 | #define TCPCB_FLAG_URG 0x20 | |
544 | #define TCPCB_FLAG_ECE 0x40 | |
545 | #define TCPCB_FLAG_CWR 0x80 | |
546 | ||
547 | __u8 sacked; /* State flags for SACK/FACK. */ | |
548 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
549 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
550 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
551 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
552 | ||
553 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
554 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) | |
555 | ||
caa20d9a | 556 | #define TCPCB_URG 0x20 /* Urgent pointer advanced here */ |
1da177e4 LT |
557 | |
558 | #define TCPCB_AT_TAIL (TCPCB_URG) | |
559 | ||
560 | __u16 urg_ptr; /* Valid w/URG flags is set. */ | |
561 | __u32 ack_seq; /* Sequence number ACK'd */ | |
562 | }; | |
563 | ||
564 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
565 | ||
566 | #include <net/tcp_ecn.h> | |
567 | ||
568 | /* Due to TSO, an SKB can be composed of multiple actual | |
569 | * packets. To keep these tracked properly, we use this. | |
570 | */ | |
571 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
572 | { | |
573 | return skb_shinfo(skb)->tso_segs; | |
574 | } | |
575 | ||
576 | /* This is valid iff tcp_skb_pcount() > 1. */ | |
577 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
578 | { | |
579 | return skb_shinfo(skb)->tso_size; | |
580 | } | |
581 | ||
582 | static inline void tcp_dec_pcount_approx(__u32 *count, | |
583 | const struct sk_buff *skb) | |
584 | { | |
585 | if (*count) { | |
586 | *count -= tcp_skb_pcount(skb); | |
587 | if ((int)*count < 0) | |
588 | *count = 0; | |
589 | } | |
590 | } | |
591 | ||
592 | static inline void tcp_packets_out_inc(struct sock *sk, | |
593 | struct tcp_sock *tp, | |
594 | const struct sk_buff *skb) | |
595 | { | |
596 | int orig = tp->packets_out; | |
597 | ||
598 | tp->packets_out += tcp_skb_pcount(skb); | |
599 | if (!orig) | |
3f421baa ACM |
600 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
601 | inet_csk(sk)->icsk_rto, TCP_RTO_MAX); | |
1da177e4 LT |
602 | } |
603 | ||
604 | static inline void tcp_packets_out_dec(struct tcp_sock *tp, | |
605 | const struct sk_buff *skb) | |
606 | { | |
607 | tp->packets_out -= tcp_skb_pcount(skb); | |
608 | } | |
609 | ||
317a76f9 SH |
610 | /* Events passed to congestion control interface */ |
611 | enum tcp_ca_event { | |
612 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
613 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
614 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
615 | CA_EVENT_FRTO, /* fast recovery timeout */ | |
616 | CA_EVENT_LOSS, /* loss timeout */ | |
617 | CA_EVENT_FAST_ACK, /* in sequence ack */ | |
618 | CA_EVENT_SLOW_ACK, /* other ack */ | |
619 | }; | |
620 | ||
621 | /* | |
622 | * Interface for adding new TCP congestion control handlers | |
623 | */ | |
624 | #define TCP_CA_NAME_MAX 16 | |
625 | struct tcp_congestion_ops { | |
626 | struct list_head list; | |
627 | ||
628 | /* initialize private data (optional) */ | |
6687e988 | 629 | void (*init)(struct sock *sk); |
317a76f9 | 630 | /* cleanup private data (optional) */ |
6687e988 | 631 | void (*release)(struct sock *sk); |
317a76f9 SH |
632 | |
633 | /* return slow start threshold (required) */ | |
6687e988 | 634 | u32 (*ssthresh)(struct sock *sk); |
317a76f9 | 635 | /* lower bound for congestion window (optional) */ |
6687e988 | 636 | u32 (*min_cwnd)(struct sock *sk); |
317a76f9 | 637 | /* do new cwnd calculation (required) */ |
6687e988 | 638 | void (*cong_avoid)(struct sock *sk, u32 ack, |
317a76f9 SH |
639 | u32 rtt, u32 in_flight, int good_ack); |
640 | /* round trip time sample per acked packet (optional) */ | |
6687e988 | 641 | void (*rtt_sample)(struct sock *sk, u32 usrtt); |
317a76f9 | 642 | /* call before changing ca_state (optional) */ |
6687e988 | 643 | void (*set_state)(struct sock *sk, u8 new_state); |
317a76f9 | 644 | /* call when cwnd event occurs (optional) */ |
6687e988 | 645 | void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); |
317a76f9 | 646 | /* new value of cwnd after loss (optional) */ |
6687e988 | 647 | u32 (*undo_cwnd)(struct sock *sk); |
317a76f9 | 648 | /* hook for packet ack accounting (optional) */ |
6687e988 | 649 | void (*pkts_acked)(struct sock *sk, u32 num_acked); |
73c1f4a0 | 650 | /* get info for inet_diag (optional) */ |
6687e988 | 651 | void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); |
317a76f9 SH |
652 | |
653 | char name[TCP_CA_NAME_MAX]; | |
654 | struct module *owner; | |
655 | }; | |
656 | ||
657 | extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
658 | extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
659 | ||
6687e988 ACM |
660 | extern void tcp_init_congestion_control(struct sock *sk); |
661 | extern void tcp_cleanup_congestion_control(struct sock *sk); | |
317a76f9 SH |
662 | extern int tcp_set_default_congestion_control(const char *name); |
663 | extern void tcp_get_default_congestion_control(char *name); | |
6687e988 | 664 | extern int tcp_set_congestion_control(struct sock *sk, const char *name); |
317a76f9 | 665 | |
5f8ef48d | 666 | extern struct tcp_congestion_ops tcp_init_congestion_ops; |
6687e988 ACM |
667 | extern u32 tcp_reno_ssthresh(struct sock *sk); |
668 | extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, | |
317a76f9 | 669 | u32 rtt, u32 in_flight, int flag); |
6687e988 | 670 | extern u32 tcp_reno_min_cwnd(struct sock *sk); |
a8acfbac | 671 | extern struct tcp_congestion_ops tcp_reno; |
317a76f9 | 672 | |
6687e988 | 673 | static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) |
317a76f9 | 674 | { |
6687e988 ACM |
675 | struct inet_connection_sock *icsk = inet_csk(sk); |
676 | ||
677 | if (icsk->icsk_ca_ops->set_state) | |
678 | icsk->icsk_ca_ops->set_state(sk, ca_state); | |
679 | icsk->icsk_ca_state = ca_state; | |
317a76f9 SH |
680 | } |
681 | ||
6687e988 | 682 | static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) |
317a76f9 | 683 | { |
6687e988 ACM |
684 | const struct inet_connection_sock *icsk = inet_csk(sk); |
685 | ||
686 | if (icsk->icsk_ca_ops->cwnd_event) | |
687 | icsk->icsk_ca_ops->cwnd_event(sk, event); | |
317a76f9 SH |
688 | } |
689 | ||
1da177e4 LT |
690 | /* This determines how many packets are "in the network" to the best |
691 | * of our knowledge. In many cases it is conservative, but where | |
692 | * detailed information is available from the receiver (via SACK | |
693 | * blocks etc.) we can make more aggressive calculations. | |
694 | * | |
695 | * Use this for decisions involving congestion control, use just | |
696 | * tp->packets_out to determine if the send queue is empty or not. | |
697 | * | |
698 | * Read this equation as: | |
699 | * | |
700 | * "Packets sent once on transmission queue" MINUS | |
701 | * "Packets left network, but not honestly ACKed yet" PLUS | |
702 | * "Packets fast retransmitted" | |
703 | */ | |
704 | static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) | |
705 | { | |
706 | return (tp->packets_out - tp->left_out + tp->retrans_out); | |
707 | } | |
708 | ||
1da177e4 LT |
709 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. |
710 | * The exception is rate halving phase, when cwnd is decreasing towards | |
711 | * ssthresh. | |
712 | */ | |
6687e988 | 713 | static inline __u32 tcp_current_ssthresh(const struct sock *sk) |
1da177e4 | 714 | { |
6687e988 ACM |
715 | const struct tcp_sock *tp = tcp_sk(sk); |
716 | if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) | |
1da177e4 LT |
717 | return tp->snd_ssthresh; |
718 | else | |
719 | return max(tp->snd_ssthresh, | |
720 | ((tp->snd_cwnd >> 1) + | |
721 | (tp->snd_cwnd >> 2))); | |
722 | } | |
723 | ||
7faffa1c SH |
724 | /* |
725 | * Linear increase during slow start | |
726 | */ | |
727 | static inline void tcp_slow_start(struct tcp_sock *tp) | |
728 | { | |
9772efb9 SH |
729 | if (sysctl_tcp_abc) { |
730 | /* RFC3465: Slow Start | |
731 | * TCP sender SHOULD increase cwnd by the number of | |
732 | * previously unacknowledged bytes ACKed by each incoming | |
733 | * acknowledgment, provided the increase is not more than L | |
734 | */ | |
735 | if (tp->bytes_acked < tp->mss_cache) | |
736 | return; | |
737 | ||
738 | /* We MAY increase by 2 if discovered delayed ack */ | |
739 | if (sysctl_tcp_abc > 1 && tp->bytes_acked > 2*tp->mss_cache) { | |
740 | if (tp->snd_cwnd < tp->snd_cwnd_clamp) | |
741 | tp->snd_cwnd++; | |
742 | } | |
743 | } | |
744 | tp->bytes_acked = 0; | |
745 | ||
7faffa1c SH |
746 | if (tp->snd_cwnd < tp->snd_cwnd_clamp) |
747 | tp->snd_cwnd++; | |
748 | } | |
749 | ||
750 | ||
1da177e4 LT |
751 | static inline void tcp_sync_left_out(struct tcp_sock *tp) |
752 | { | |
753 | if (tp->rx_opt.sack_ok && | |
754 | (tp->sacked_out >= tp->packets_out - tp->lost_out)) | |
755 | tp->sacked_out = tp->packets_out - tp->lost_out; | |
756 | tp->left_out = tp->sacked_out + tp->lost_out; | |
757 | } | |
758 | ||
d1b04c08 | 759 | /* Set slow start threshold and cwnd not falling to slow start */ |
6687e988 | 760 | static inline void __tcp_enter_cwr(struct sock *sk) |
1da177e4 | 761 | { |
6687e988 ACM |
762 | const struct inet_connection_sock *icsk = inet_csk(sk); |
763 | struct tcp_sock *tp = tcp_sk(sk); | |
764 | ||
1da177e4 | 765 | tp->undo_marker = 0; |
6687e988 | 766 | tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); |
1da177e4 LT |
767 | tp->snd_cwnd = min(tp->snd_cwnd, |
768 | tcp_packets_in_flight(tp) + 1U); | |
769 | tp->snd_cwnd_cnt = 0; | |
770 | tp->high_seq = tp->snd_nxt; | |
771 | tp->snd_cwnd_stamp = tcp_time_stamp; | |
772 | TCP_ECN_queue_cwr(tp); | |
773 | } | |
774 | ||
6687e988 | 775 | static inline void tcp_enter_cwr(struct sock *sk) |
1da177e4 | 776 | { |
6687e988 ACM |
777 | struct tcp_sock *tp = tcp_sk(sk); |
778 | ||
1da177e4 | 779 | tp->prior_ssthresh = 0; |
9772efb9 | 780 | tp->bytes_acked = 0; |
6687e988 ACM |
781 | if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { |
782 | __tcp_enter_cwr(sk); | |
783 | tcp_set_ca_state(sk, TCP_CA_CWR); | |
1da177e4 LT |
784 | } |
785 | } | |
786 | ||
787 | extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); | |
788 | ||
789 | /* Slow start with delack produces 3 packets of burst, so that | |
790 | * it is safe "de facto". | |
791 | */ | |
792 | static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) | |
793 | { | |
794 | return 3; | |
795 | } | |
796 | ||
f4805ede SH |
797 | /* RFC2861 Check whether we are limited by application or congestion window |
798 | * This is the inverse of cwnd check in tcp_tso_should_defer | |
799 | */ | |
800 | static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight) | |
801 | { | |
802 | const struct tcp_sock *tp = tcp_sk(sk); | |
803 | u32 left; | |
804 | ||
805 | if (in_flight >= tp->snd_cwnd) | |
806 | return 1; | |
807 | ||
808 | if (!(sk->sk_route_caps & NETIF_F_TSO)) | |
809 | return 0; | |
810 | ||
811 | left = tp->snd_cwnd - in_flight; | |
812 | if (sysctl_tcp_tso_win_divisor) | |
813 | return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd; | |
814 | else | |
815 | return left <= tcp_max_burst(tp); | |
816 | } | |
817 | ||
1da177e4 LT |
818 | static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, |
819 | const struct sk_buff *skb) | |
820 | { | |
821 | if (skb->len < mss) | |
822 | tp->snd_sml = TCP_SKB_CB(skb)->end_seq; | |
823 | } | |
824 | ||
1da177e4 LT |
825 | static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) |
826 | { | |
463c84b9 ACM |
827 | const struct inet_connection_sock *icsk = inet_csk(sk); |
828 | if (!tp->packets_out && !icsk->icsk_pending) | |
3f421baa ACM |
829 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, |
830 | icsk->icsk_rto, TCP_RTO_MAX); | |
1da177e4 LT |
831 | } |
832 | ||
1da177e4 LT |
833 | static __inline__ void tcp_push_pending_frames(struct sock *sk, |
834 | struct tcp_sock *tp) | |
835 | { | |
836 | __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); | |
837 | } | |
838 | ||
1da177e4 LT |
839 | static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) |
840 | { | |
841 | tp->snd_wl1 = seq; | |
842 | } | |
843 | ||
844 | static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) | |
845 | { | |
846 | tp->snd_wl1 = seq; | |
847 | } | |
848 | ||
1da177e4 LT |
849 | /* |
850 | * Calculate(/check) TCP checksum | |
851 | */ | |
852 | static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, | |
853 | unsigned long saddr, unsigned long daddr, | |
854 | unsigned long base) | |
855 | { | |
856 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
857 | } | |
858 | ||
859 | static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) | |
860 | { | |
fb286bb2 | 861 | return __skb_checksum_complete(skb); |
1da177e4 LT |
862 | } |
863 | ||
864 | static __inline__ int tcp_checksum_complete(struct sk_buff *skb) | |
865 | { | |
866 | return skb->ip_summed != CHECKSUM_UNNECESSARY && | |
867 | __tcp_checksum_complete(skb); | |
868 | } | |
869 | ||
870 | /* Prequeue for VJ style copy to user, combined with checksumming. */ | |
871 | ||
872 | static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) | |
873 | { | |
874 | tp->ucopy.task = NULL; | |
875 | tp->ucopy.len = 0; | |
876 | tp->ucopy.memory = 0; | |
877 | skb_queue_head_init(&tp->ucopy.prequeue); | |
878 | } | |
879 | ||
880 | /* Packet is added to VJ-style prequeue for processing in process | |
881 | * context, if a reader task is waiting. Apparently, this exciting | |
882 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) | |
883 | * failed somewhere. Latency? Burstiness? Well, at least now we will | |
884 | * see, why it failed. 8)8) --ANK | |
885 | * | |
886 | * NOTE: is this not too big to inline? | |
887 | */ | |
888 | static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) | |
889 | { | |
890 | struct tcp_sock *tp = tcp_sk(sk); | |
891 | ||
892 | if (!sysctl_tcp_low_latency && tp->ucopy.task) { | |
893 | __skb_queue_tail(&tp->ucopy.prequeue, skb); | |
894 | tp->ucopy.memory += skb->truesize; | |
895 | if (tp->ucopy.memory > sk->sk_rcvbuf) { | |
896 | struct sk_buff *skb1; | |
897 | ||
898 | BUG_ON(sock_owned_by_user(sk)); | |
899 | ||
900 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { | |
901 | sk->sk_backlog_rcv(sk, skb1); | |
902 | NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); | |
903 | } | |
904 | ||
905 | tp->ucopy.memory = 0; | |
906 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { | |
907 | wake_up_interruptible(sk->sk_sleep); | |
463c84b9 ACM |
908 | if (!inet_csk_ack_scheduled(sk)) |
909 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
3f421baa ACM |
910 | (3 * TCP_RTO_MIN) / 4, |
911 | TCP_RTO_MAX); | |
1da177e4 LT |
912 | } |
913 | return 1; | |
914 | } | |
915 | return 0; | |
916 | } | |
917 | ||
918 | ||
919 | #undef STATE_TRACE | |
920 | ||
921 | #ifdef STATE_TRACE | |
922 | static const char *statename[]={ | |
923 | "Unused","Established","Syn Sent","Syn Recv", | |
924 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
925 | "Close Wait","Last ACK","Listen","Closing" | |
926 | }; | |
927 | #endif | |
928 | ||
929 | static __inline__ void tcp_set_state(struct sock *sk, int state) | |
930 | { | |
931 | int oldstate = sk->sk_state; | |
932 | ||
933 | switch (state) { | |
934 | case TCP_ESTABLISHED: | |
935 | if (oldstate != TCP_ESTABLISHED) | |
936 | TCP_INC_STATS(TCP_MIB_CURRESTAB); | |
937 | break; | |
938 | ||
939 | case TCP_CLOSE: | |
940 | if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) | |
941 | TCP_INC_STATS(TCP_MIB_ESTABRESETS); | |
942 | ||
943 | sk->sk_prot->unhash(sk); | |
463c84b9 | 944 | if (inet_csk(sk)->icsk_bind_hash && |
1da177e4 | 945 | !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) |
2d8c4ce5 | 946 | inet_put_port(&tcp_hashinfo, sk); |
1da177e4 LT |
947 | /* fall through */ |
948 | default: | |
949 | if (oldstate==TCP_ESTABLISHED) | |
950 | TCP_DEC_STATS(TCP_MIB_CURRESTAB); | |
951 | } | |
952 | ||
953 | /* Change state AFTER socket is unhashed to avoid closed | |
954 | * socket sitting in hash tables. | |
955 | */ | |
956 | sk->sk_state = state; | |
957 | ||
958 | #ifdef STATE_TRACE | |
959 | SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); | |
960 | #endif | |
961 | } | |
962 | ||
963 | static __inline__ void tcp_done(struct sock *sk) | |
964 | { | |
965 | tcp_set_state(sk, TCP_CLOSE); | |
966 | tcp_clear_xmit_timers(sk); | |
967 | ||
968 | sk->sk_shutdown = SHUTDOWN_MASK; | |
969 | ||
970 | if (!sock_flag(sk, SOCK_DEAD)) | |
971 | sk->sk_state_change(sk); | |
972 | else | |
0a5578cf | 973 | inet_csk_destroy_sock(sk); |
1da177e4 LT |
974 | } |
975 | ||
976 | static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) | |
977 | { | |
978 | rx_opt->dsack = 0; | |
979 | rx_opt->eff_sacks = 0; | |
980 | rx_opt->num_sacks = 0; | |
981 | } | |
982 | ||
983 | static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) | |
984 | { | |
985 | if (tp->rx_opt.tstamp_ok) { | |
986 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | | |
987 | (TCPOPT_NOP << 16) | | |
988 | (TCPOPT_TIMESTAMP << 8) | | |
989 | TCPOLEN_TIMESTAMP); | |
990 | *ptr++ = htonl(tstamp); | |
991 | *ptr++ = htonl(tp->rx_opt.ts_recent); | |
992 | } | |
993 | if (tp->rx_opt.eff_sacks) { | |
994 | struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; | |
995 | int this_sack; | |
996 | ||
8639a11e ACM |
997 | *ptr++ = htonl((TCPOPT_NOP << 24) | |
998 | (TCPOPT_NOP << 16) | | |
999 | (TCPOPT_SACK << 8) | | |
1000 | (TCPOLEN_SACK_BASE + (tp->rx_opt.eff_sacks * | |
1001 | TCPOLEN_SACK_PERBLOCK))); | |
1da177e4 LT |
1002 | for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { |
1003 | *ptr++ = htonl(sp[this_sack].start_seq); | |
1004 | *ptr++ = htonl(sp[this_sack].end_seq); | |
1005 | } | |
1006 | if (tp->rx_opt.dsack) { | |
1007 | tp->rx_opt.dsack = 0; | |
1008 | tp->rx_opt.eff_sacks--; | |
1009 | } | |
1010 | } | |
1011 | } | |
1012 | ||
1013 | /* Construct a tcp options header for a SYN or SYN_ACK packet. | |
1014 | * If this is every changed make sure to change the definition of | |
1015 | * MAX_SYN_SIZE to match the new maximum number of options that you | |
1016 | * can generate. | |
1017 | */ | |
1018 | static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, | |
1019 | int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) | |
1020 | { | |
1021 | /* We always get an MSS option. | |
1022 | * The option bytes which will be seen in normal data | |
1023 | * packets should timestamps be used, must be in the MSS | |
1024 | * advertised. But we subtract them from tp->mss_cache so | |
1025 | * that calculations in tcp_sendmsg are simpler etc. | |
1026 | * So account for this fact here if necessary. If we | |
1027 | * don't do this correctly, as a receiver we won't | |
1028 | * recognize data packets as being full sized when we | |
1029 | * should, and thus we won't abide by the delayed ACK | |
1030 | * rules correctly. | |
1031 | * SACKs don't matter, we never delay an ACK when we | |
1032 | * have any of those going out. | |
1033 | */ | |
1034 | *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); | |
1035 | if (ts) { | |
1036 | if(sack) | |
1037 | *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | | |
1038 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1039 | else | |
1040 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1041 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1042 | *ptr++ = htonl(tstamp); /* TSVAL */ | |
1043 | *ptr++ = htonl(ts_recent); /* TSECR */ | |
1044 | } else if(sack) | |
1045 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1046 | (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); | |
1047 | if (offer_wscale) | |
1048 | *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); | |
1049 | } | |
1050 | ||
1051 | /* Determine a window scaling and initial window to offer. */ | |
1052 | extern void tcp_select_initial_window(int __space, __u32 mss, | |
1053 | __u32 *rcv_wnd, __u32 *window_clamp, | |
1054 | int wscale_ok, __u8 *rcv_wscale); | |
1055 | ||
1056 | static inline int tcp_win_from_space(int space) | |
1057 | { | |
1058 | return sysctl_tcp_adv_win_scale<=0 ? | |
1059 | (space>>(-sysctl_tcp_adv_win_scale)) : | |
1060 | space - (space>>sysctl_tcp_adv_win_scale); | |
1061 | } | |
1062 | ||
1063 | /* Note: caller must be prepared to deal with negative returns */ | |
1064 | static inline int tcp_space(const struct sock *sk) | |
1065 | { | |
1066 | return tcp_win_from_space(sk->sk_rcvbuf - | |
1067 | atomic_read(&sk->sk_rmem_alloc)); | |
1068 | } | |
1069 | ||
1070 | static inline int tcp_full_space(const struct sock *sk) | |
1071 | { | |
1072 | return tcp_win_from_space(sk->sk_rcvbuf); | |
1073 | } | |
1074 | ||
60236fdd | 1075 | static __inline__ void tcp_openreq_init(struct request_sock *req, |
1da177e4 LT |
1076 | struct tcp_options_received *rx_opt, |
1077 | struct sk_buff *skb) | |
1078 | { | |
2e6599cb ACM |
1079 | struct inet_request_sock *ireq = inet_rsk(req); |
1080 | ||
1da177e4 | 1081 | req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
2e6599cb | 1082 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
1da177e4 LT |
1083 | req->mss = rx_opt->mss_clamp; |
1084 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; | |
2e6599cb ACM |
1085 | ireq->tstamp_ok = rx_opt->tstamp_ok; |
1086 | ireq->sack_ok = rx_opt->sack_ok; | |
1087 | ireq->snd_wscale = rx_opt->snd_wscale; | |
1088 | ireq->wscale_ok = rx_opt->wscale_ok; | |
1089 | ireq->acked = 0; | |
1090 | ireq->ecn_ok = 0; | |
1091 | ireq->rmt_port = skb->h.th->source; | |
1da177e4 LT |
1092 | } |
1093 | ||
1094 | extern void tcp_enter_memory_pressure(void); | |
1095 | ||
1da177e4 LT |
1096 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) |
1097 | { | |
1098 | return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; | |
1099 | } | |
1100 | ||
1101 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1102 | { | |
1103 | return tp->keepalive_time ? : sysctl_tcp_keepalive_time; | |
1104 | } | |
1105 | ||
463c84b9 | 1106 | static inline int tcp_fin_time(const struct sock *sk) |
1da177e4 | 1107 | { |
463c84b9 ACM |
1108 | int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; |
1109 | const int rto = inet_csk(sk)->icsk_rto; | |
1da177e4 | 1110 | |
463c84b9 ACM |
1111 | if (fin_timeout < (rto << 2) - (rto >> 1)) |
1112 | fin_timeout = (rto << 2) - (rto >> 1); | |
1da177e4 LT |
1113 | |
1114 | return fin_timeout; | |
1115 | } | |
1116 | ||
1117 | static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) | |
1118 | { | |
1119 | if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) | |
1120 | return 0; | |
1121 | if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) | |
1122 | return 0; | |
1123 | ||
1124 | /* RST segments are not recommended to carry timestamp, | |
1125 | and, if they do, it is recommended to ignore PAWS because | |
1126 | "their cleanup function should take precedence over timestamps." | |
1127 | Certainly, it is mistake. It is necessary to understand the reasons | |
1128 | of this constraint to relax it: if peer reboots, clock may go | |
1129 | out-of-sync and half-open connections will not be reset. | |
1130 | Actually, the problem would be not existing if all | |
1131 | the implementations followed draft about maintaining clock | |
1132 | via reboots. Linux-2.2 DOES NOT! | |
1133 | ||
1134 | However, we can relax time bounds for RST segments to MSL. | |
1135 | */ | |
1136 | if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) | |
1137 | return 0; | |
1138 | return 1; | |
1139 | } | |
1140 | ||
1da177e4 LT |
1141 | #define TCP_CHECK_TIMER(sk) do { } while (0) |
1142 | ||
1143 | static inline int tcp_use_frto(const struct sock *sk) | |
1144 | { | |
1145 | const struct tcp_sock *tp = tcp_sk(sk); | |
1146 | ||
1147 | /* F-RTO must be activated in sysctl and there must be some | |
1148 | * unsent new data, and the advertised window should allow | |
1149 | * sending it. | |
1150 | */ | |
1151 | return (sysctl_tcp_frto && sk->sk_send_head && | |
1152 | !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, | |
1153 | tp->snd_una + tp->snd_wnd)); | |
1154 | } | |
1155 | ||
1156 | static inline void tcp_mib_init(void) | |
1157 | { | |
1158 | /* See RFC 2012 */ | |
1159 | TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); | |
1160 | TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1161 | TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1162 | TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); | |
1163 | } | |
1164 | ||
6a438bbe SH |
1165 | /*from STCP */ |
1166 | static inline void clear_all_retrans_hints(struct tcp_sock *tp){ | |
1167 | tp->lost_skb_hint = NULL; | |
1168 | tp->scoreboard_skb_hint = NULL; | |
1169 | tp->retransmit_skb_hint = NULL; | |
1170 | tp->forward_skb_hint = NULL; | |
1171 | tp->fastpath_skb_hint = NULL; | |
1172 | } | |
1173 | ||
1da177e4 LT |
1174 | /* /proc */ |
1175 | enum tcp_seq_states { | |
1176 | TCP_SEQ_STATE_LISTENING, | |
1177 | TCP_SEQ_STATE_OPENREQ, | |
1178 | TCP_SEQ_STATE_ESTABLISHED, | |
1179 | TCP_SEQ_STATE_TIME_WAIT, | |
1180 | }; | |
1181 | ||
1182 | struct tcp_seq_afinfo { | |
1183 | struct module *owner; | |
1184 | char *name; | |
1185 | sa_family_t family; | |
1186 | int (*seq_show) (struct seq_file *m, void *v); | |
1187 | struct file_operations *seq_fops; | |
1188 | }; | |
1189 | ||
1190 | struct tcp_iter_state { | |
1191 | sa_family_t family; | |
1192 | enum tcp_seq_states state; | |
1193 | struct sock *syn_wait_sk; | |
1194 | int bucket, sbucket, num, uid; | |
1195 | struct seq_operations seq_ops; | |
1196 | }; | |
1197 | ||
1198 | extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); | |
1199 | extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); | |
1200 | ||
20380731 ACM |
1201 | extern struct request_sock_ops tcp_request_sock_ops; |
1202 | ||
1203 | extern int tcp_v4_destroy_sock(struct sock *sk); | |
1204 | ||
1205 | #ifdef CONFIG_PROC_FS | |
1206 | extern int tcp4_proc_init(void); | |
1207 | extern void tcp4_proc_exit(void); | |
1208 | #endif | |
1209 | ||
1210 | extern void tcp_v4_init(struct net_proto_family *ops); | |
1211 | extern void tcp_init(void); | |
1212 | ||
1da177e4 | 1213 | #endif /* _TCP_H */ |