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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> | |
3f421baa ACM |
30 | |
31 | #include <net/inet_connection_sock.h> | |
295ff7ed | 32 | #include <net/inet_timewait_sock.h> |
77d8bf9c | 33 | #include <net/inet_hashtables.h> |
1da177e4 | 34 | #include <net/checksum.h> |
2e6599cb | 35 | #include <net/request_sock.h> |
1da177e4 LT |
36 | #include <net/sock.h> |
37 | #include <net/snmp.h> | |
38 | #include <net/ip.h> | |
c752f073 ACM |
39 | #include <net/tcp_states.h> |
40 | ||
1da177e4 LT |
41 | #include <linux/seq_file.h> |
42 | ||
6e04e021 | 43 | extern struct inet_hashinfo tcp_hashinfo; |
1da177e4 | 44 | |
1da177e4 | 45 | extern atomic_t tcp_orphan_count; |
1da177e4 | 46 | extern void tcp_time_wait(struct sock *sk, int state, int timeo); |
1da177e4 | 47 | |
1da177e4 LT |
48 | #define MAX_TCP_HEADER (128 + MAX_HEADER) |
49 | ||
50 | /* | |
51 | * Never offer a window over 32767 without using window scaling. Some | |
52 | * poor stacks do signed 16bit maths! | |
53 | */ | |
54 | #define MAX_TCP_WINDOW 32767U | |
55 | ||
56 | /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ | |
57 | #define TCP_MIN_MSS 88U | |
58 | ||
59 | /* Minimal RCV_MSS. */ | |
60 | #define TCP_MIN_RCVMSS 536U | |
61 | ||
62 | /* After receiving this amount of duplicate ACKs fast retransmit starts. */ | |
63 | #define TCP_FASTRETRANS_THRESH 3 | |
64 | ||
65 | /* Maximal reordering. */ | |
66 | #define TCP_MAX_REORDERING 127 | |
67 | ||
68 | /* Maximal number of ACKs sent quickly to accelerate slow-start. */ | |
69 | #define TCP_MAX_QUICKACKS 16U | |
70 | ||
71 | /* urg_data states */ | |
72 | #define TCP_URG_VALID 0x0100 | |
73 | #define TCP_URG_NOTYET 0x0200 | |
74 | #define TCP_URG_READ 0x0400 | |
75 | ||
76 | #define TCP_RETR1 3 /* | |
77 | * This is how many retries it does before it | |
78 | * tries to figure out if the gateway is | |
79 | * down. Minimal RFC value is 3; it corresponds | |
80 | * to ~3sec-8min depending on RTO. | |
81 | */ | |
82 | ||
83 | #define TCP_RETR2 15 /* | |
84 | * This should take at least | |
85 | * 90 minutes to time out. | |
86 | * RFC1122 says that the limit is 100 sec. | |
87 | * 15 is ~13-30min depending on RTO. | |
88 | */ | |
89 | ||
90 | #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a | |
91 | * connection: ~180sec is RFC minumum */ | |
92 | ||
93 | #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a | |
94 | * connection: ~180sec is RFC minumum */ | |
95 | ||
96 | ||
97 | #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned | |
98 | * socket. 7 is ~50sec-16min. | |
99 | */ | |
100 | ||
101 | ||
102 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT | |
103 | * state, about 60 seconds */ | |
104 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
105 | /* BSD style FIN_WAIT2 deadlock breaker. | |
106 | * It used to be 3min, new value is 60sec, | |
107 | * to combine FIN-WAIT-2 timeout with | |
108 | * TIME-WAIT timer. | |
109 | */ | |
110 | ||
111 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
112 | #if HZ >= 100 | |
113 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
114 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
115 | #else | |
116 | #define TCP_DELACK_MIN 4U | |
117 | #define TCP_ATO_MIN 4U | |
118 | #endif | |
119 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
120 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
121 | #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ | |
122 | ||
123 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
124 | * for local resources. | |
125 | */ | |
126 | ||
127 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
128 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
129 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
130 | ||
131 | #define MAX_TCP_KEEPIDLE 32767 | |
132 | #define MAX_TCP_KEEPINTVL 32767 | |
133 | #define MAX_TCP_KEEPCNT 127 | |
134 | #define MAX_TCP_SYNCNT 127 | |
135 | ||
136 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
137 | #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ | |
138 | ||
139 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
140 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
141 | * after this time. It should be equal | |
142 | * (or greater than) TCP_TIMEWAIT_LEN | |
143 | * to provide reliability equal to one | |
144 | * provided by timewait state. | |
145 | */ | |
146 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
147 | * timestamps. It must be less than | |
148 | * minimal timewait lifetime. | |
149 | */ | |
1da177e4 LT |
150 | /* |
151 | * TCP option | |
152 | */ | |
153 | ||
154 | #define TCPOPT_NOP 1 /* Padding */ | |
155 | #define TCPOPT_EOL 0 /* End of options */ | |
156 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
157 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
158 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
159 | #define TCPOPT_SACK 5 /* SACK Block */ | |
160 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
161 | ||
162 | /* | |
163 | * TCP option lengths | |
164 | */ | |
165 | ||
166 | #define TCPOLEN_MSS 4 | |
167 | #define TCPOLEN_WINDOW 3 | |
168 | #define TCPOLEN_SACK_PERM 2 | |
169 | #define TCPOLEN_TIMESTAMP 10 | |
170 | ||
171 | /* But this is what stacks really send out. */ | |
172 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
173 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
174 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
175 | #define TCPOLEN_SACK_BASE 2 | |
176 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
177 | #define TCPOLEN_SACK_PERBLOCK 8 | |
178 | ||
1da177e4 LT |
179 | /* Flags in tp->nonagle */ |
180 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
181 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
182 | #define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */ | |
183 | ||
295ff7ed ACM |
184 | extern struct inet_timewait_death_row tcp_death_row; |
185 | ||
1da177e4 | 186 | /* sysctl variables for tcp */ |
1da177e4 LT |
187 | extern int sysctl_tcp_timestamps; |
188 | extern int sysctl_tcp_window_scaling; | |
189 | extern int sysctl_tcp_sack; | |
190 | extern int sysctl_tcp_fin_timeout; | |
1da177e4 LT |
191 | extern int sysctl_tcp_keepalive_time; |
192 | extern int sysctl_tcp_keepalive_probes; | |
193 | extern int sysctl_tcp_keepalive_intvl; | |
194 | extern int sysctl_tcp_syn_retries; | |
195 | extern int sysctl_tcp_synack_retries; | |
196 | extern int sysctl_tcp_retries1; | |
197 | extern int sysctl_tcp_retries2; | |
198 | extern int sysctl_tcp_orphan_retries; | |
199 | extern int sysctl_tcp_syncookies; | |
200 | extern int sysctl_tcp_retrans_collapse; | |
201 | extern int sysctl_tcp_stdurg; | |
202 | extern int sysctl_tcp_rfc1337; | |
203 | extern int sysctl_tcp_abort_on_overflow; | |
204 | extern int sysctl_tcp_max_orphans; | |
1da177e4 LT |
205 | extern int sysctl_tcp_fack; |
206 | extern int sysctl_tcp_reordering; | |
207 | extern int sysctl_tcp_ecn; | |
208 | extern int sysctl_tcp_dsack; | |
209 | extern int sysctl_tcp_mem[3]; | |
210 | extern int sysctl_tcp_wmem[3]; | |
211 | extern int sysctl_tcp_rmem[3]; | |
212 | extern int sysctl_tcp_app_win; | |
213 | extern int sysctl_tcp_adv_win_scale; | |
214 | extern int sysctl_tcp_tw_reuse; | |
215 | extern int sysctl_tcp_frto; | |
216 | extern int sysctl_tcp_low_latency; | |
1da177e4 | 217 | extern int sysctl_tcp_nometrics_save; |
1da177e4 LT |
218 | extern int sysctl_tcp_moderate_rcvbuf; |
219 | extern int sysctl_tcp_tso_win_divisor; | |
220 | ||
221 | extern atomic_t tcp_memory_allocated; | |
222 | extern atomic_t tcp_sockets_allocated; | |
223 | extern int tcp_memory_pressure; | |
224 | ||
1da177e4 LT |
225 | /* |
226 | * Pointers to address related TCP functions | |
227 | * (i.e. things that depend on the address family) | |
228 | */ | |
229 | ||
230 | struct tcp_func { | |
231 | int (*queue_xmit) (struct sk_buff *skb, | |
232 | int ipfragok); | |
233 | ||
234 | void (*send_check) (struct sock *sk, | |
235 | struct tcphdr *th, | |
236 | int len, | |
237 | struct sk_buff *skb); | |
238 | ||
239 | int (*rebuild_header) (struct sock *sk); | |
240 | ||
241 | int (*conn_request) (struct sock *sk, | |
242 | struct sk_buff *skb); | |
243 | ||
244 | struct sock * (*syn_recv_sock) (struct sock *sk, | |
245 | struct sk_buff *skb, | |
60236fdd | 246 | struct request_sock *req, |
1da177e4 LT |
247 | struct dst_entry *dst); |
248 | ||
249 | int (*remember_stamp) (struct sock *sk); | |
250 | ||
251 | __u16 net_header_len; | |
252 | ||
253 | int (*setsockopt) (struct sock *sk, | |
254 | int level, | |
255 | int optname, | |
256 | char __user *optval, | |
257 | int optlen); | |
258 | ||
259 | int (*getsockopt) (struct sock *sk, | |
260 | int level, | |
261 | int optname, | |
262 | char __user *optval, | |
263 | int __user *optlen); | |
264 | ||
265 | ||
266 | void (*addr2sockaddr) (struct sock *sk, | |
267 | struct sockaddr *); | |
268 | ||
269 | int sockaddr_len; | |
270 | }; | |
271 | ||
272 | /* | |
273 | * The next routines deal with comparing 32 bit unsigned ints | |
274 | * and worry about wraparound (automatic with unsigned arithmetic). | |
275 | */ | |
276 | ||
277 | static inline int before(__u32 seq1, __u32 seq2) | |
278 | { | |
279 | return (__s32)(seq1-seq2) < 0; | |
280 | } | |
281 | ||
282 | static inline int after(__u32 seq1, __u32 seq2) | |
283 | { | |
284 | return (__s32)(seq2-seq1) < 0; | |
285 | } | |
286 | ||
287 | ||
288 | /* is s2<=s1<=s3 ? */ | |
289 | static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) | |
290 | { | |
291 | return seq3 - seq2 >= seq1 - seq2; | |
292 | } | |
293 | ||
294 | ||
295 | extern struct proto tcp_prot; | |
296 | ||
297 | DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); | |
298 | #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) | |
299 | #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) | |
300 | #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) | |
301 | #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) | |
302 | #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) | |
303 | #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) | |
304 | ||
1da177e4 LT |
305 | extern void tcp_v4_err(struct sk_buff *skb, u32); |
306 | ||
307 | extern void tcp_shutdown (struct sock *sk, int how); | |
308 | ||
309 | extern int tcp_v4_rcv(struct sk_buff *skb); | |
310 | ||
311 | extern int tcp_v4_remember_stamp(struct sock *sk); | |
312 | ||
8feaf0c0 | 313 | extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); |
1da177e4 LT |
314 | |
315 | extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, | |
316 | struct msghdr *msg, size_t size); | |
317 | extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); | |
318 | ||
319 | extern int tcp_ioctl(struct sock *sk, | |
320 | int cmd, | |
321 | unsigned long arg); | |
322 | ||
323 | extern int tcp_rcv_state_process(struct sock *sk, | |
324 | struct sk_buff *skb, | |
325 | struct tcphdr *th, | |
326 | unsigned len); | |
327 | ||
328 | extern int tcp_rcv_established(struct sock *sk, | |
329 | struct sk_buff *skb, | |
330 | struct tcphdr *th, | |
331 | unsigned len); | |
332 | ||
333 | extern void tcp_rcv_space_adjust(struct sock *sk); | |
334 | ||
463c84b9 ACM |
335 | static inline void tcp_dec_quickack_mode(struct sock *sk, |
336 | const unsigned int pkts) | |
1da177e4 | 337 | { |
463c84b9 | 338 | struct inet_connection_sock *icsk = inet_csk(sk); |
fc6415bc | 339 | |
463c84b9 ACM |
340 | if (icsk->icsk_ack.quick) { |
341 | if (pkts >= icsk->icsk_ack.quick) { | |
342 | icsk->icsk_ack.quick = 0; | |
fc6415bc | 343 | /* Leaving quickack mode we deflate ATO. */ |
463c84b9 | 344 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
fc6415bc | 345 | } else |
463c84b9 | 346 | icsk->icsk_ack.quick -= pkts; |
1da177e4 LT |
347 | } |
348 | } | |
349 | ||
463c84b9 | 350 | extern void tcp_enter_quickack_mode(struct sock *sk); |
1da177e4 | 351 | |
1da177e4 LT |
352 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
353 | { | |
354 | rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
355 | } | |
356 | ||
357 | enum tcp_tw_status | |
358 | { | |
359 | TCP_TW_SUCCESS = 0, | |
360 | TCP_TW_RST = 1, | |
361 | TCP_TW_ACK = 2, | |
362 | TCP_TW_SYN = 3 | |
363 | }; | |
364 | ||
365 | ||
8feaf0c0 | 366 | extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, |
1da177e4 | 367 | struct sk_buff *skb, |
8feaf0c0 | 368 | const struct tcphdr *th); |
1da177e4 LT |
369 | |
370 | extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, | |
60236fdd ACM |
371 | struct request_sock *req, |
372 | struct request_sock **prev); | |
1da177e4 LT |
373 | extern int tcp_child_process(struct sock *parent, |
374 | struct sock *child, | |
375 | struct sk_buff *skb); | |
376 | extern void tcp_enter_frto(struct sock *sk); | |
377 | extern void tcp_enter_loss(struct sock *sk, int how); | |
378 | extern void tcp_clear_retrans(struct tcp_sock *tp); | |
379 | extern void tcp_update_metrics(struct sock *sk); | |
380 | ||
381 | extern void tcp_close(struct sock *sk, | |
382 | long timeout); | |
1da177e4 LT |
383 | extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); |
384 | ||
385 | extern int tcp_getsockopt(struct sock *sk, int level, | |
386 | int optname, | |
387 | char __user *optval, | |
388 | int __user *optlen); | |
389 | extern int tcp_setsockopt(struct sock *sk, int level, | |
390 | int optname, char __user *optval, | |
391 | int optlen); | |
392 | extern void tcp_set_keepalive(struct sock *sk, int val); | |
393 | extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, | |
394 | struct msghdr *msg, | |
395 | size_t len, int nonblock, | |
396 | int flags, int *addr_len); | |
397 | ||
1da177e4 LT |
398 | extern void tcp_parse_options(struct sk_buff *skb, |
399 | struct tcp_options_received *opt_rx, | |
400 | int estab); | |
401 | ||
402 | /* | |
403 | * TCP v4 functions exported for the inet6 API | |
404 | */ | |
405 | ||
1da177e4 LT |
406 | extern void tcp_v4_send_check(struct sock *sk, |
407 | struct tcphdr *th, int len, | |
408 | struct sk_buff *skb); | |
409 | ||
410 | extern int tcp_v4_conn_request(struct sock *sk, | |
411 | struct sk_buff *skb); | |
412 | ||
413 | extern struct sock * tcp_create_openreq_child(struct sock *sk, | |
60236fdd | 414 | struct request_sock *req, |
1da177e4 LT |
415 | struct sk_buff *skb); |
416 | ||
417 | extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, | |
418 | struct sk_buff *skb, | |
60236fdd | 419 | struct request_sock *req, |
1da177e4 LT |
420 | struct dst_entry *dst); |
421 | ||
422 | extern int tcp_v4_do_rcv(struct sock *sk, | |
423 | struct sk_buff *skb); | |
424 | ||
425 | extern int tcp_v4_connect(struct sock *sk, | |
426 | struct sockaddr *uaddr, | |
427 | int addr_len); | |
428 | ||
429 | extern int tcp_connect(struct sock *sk); | |
430 | ||
431 | extern struct sk_buff * tcp_make_synack(struct sock *sk, | |
432 | struct dst_entry *dst, | |
60236fdd | 433 | struct request_sock *req); |
1da177e4 LT |
434 | |
435 | extern int tcp_disconnect(struct sock *sk, int flags); | |
436 | ||
437 | extern void tcp_unhash(struct sock *sk); | |
438 | ||
439 | extern int tcp_v4_hash_connecting(struct sock *sk); | |
440 | ||
441 | ||
442 | /* From syncookies.c */ | |
443 | extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, | |
444 | struct ip_options *opt); | |
445 | extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, | |
446 | __u16 *mss); | |
447 | ||
448 | /* tcp_output.c */ | |
449 | ||
f6302d1d | 450 | extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, |
a2e2a59c | 451 | unsigned int cur_mss, int nonagle); |
f6302d1d | 452 | extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); |
1da177e4 LT |
453 | extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); |
454 | extern void tcp_xmit_retransmit_queue(struct sock *); | |
455 | extern void tcp_simple_retransmit(struct sock *); | |
456 | extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
457 | ||
458 | extern void tcp_send_probe0(struct sock *); | |
459 | extern void tcp_send_partial(struct sock *); | |
460 | extern int tcp_write_wakeup(struct sock *); | |
461 | extern void tcp_send_fin(struct sock *sk); | |
86a76caf VF |
462 | extern void tcp_send_active_reset(struct sock *sk, |
463 | unsigned int __nocast priority); | |
1da177e4 | 464 | extern int tcp_send_synack(struct sock *); |
c1b4a7e6 | 465 | extern void tcp_push_one(struct sock *, unsigned int mss_now); |
1da177e4 LT |
466 | extern void tcp_send_ack(struct sock *sk); |
467 | extern void tcp_send_delayed_ack(struct sock *sk); | |
468 | ||
a762a980 DM |
469 | /* tcp_input.c */ |
470 | extern void tcp_cwnd_application_limited(struct sock *sk); | |
471 | ||
1da177e4 LT |
472 | /* tcp_timer.c */ |
473 | extern void tcp_init_xmit_timers(struct sock *); | |
463c84b9 ACM |
474 | static inline void tcp_clear_xmit_timers(struct sock *sk) |
475 | { | |
476 | inet_csk_clear_xmit_timers(sk); | |
477 | } | |
1da177e4 | 478 | |
1da177e4 LT |
479 | extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); |
480 | extern unsigned int tcp_current_mss(struct sock *sk, int large); | |
481 | ||
1da177e4 LT |
482 | /* tcp_diag.c */ |
483 | extern void tcp_get_info(struct sock *, struct tcp_info *); | |
484 | ||
485 | /* Read 'sendfile()'-style from a TCP socket */ | |
486 | typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, | |
487 | unsigned int, size_t); | |
488 | extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
489 | sk_read_actor_t recv_actor); | |
490 | ||
1da177e4 LT |
491 | /* Initialize RCV_MSS value. |
492 | * RCV_MSS is an our guess about MSS used by the peer. | |
493 | * We haven't any direct information about the MSS. | |
494 | * It's better to underestimate the RCV_MSS rather than overestimate. | |
495 | * Overestimations make us ACKing less frequently than needed. | |
496 | * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). | |
497 | */ | |
498 | ||
499 | static inline void tcp_initialize_rcv_mss(struct sock *sk) | |
500 | { | |
501 | struct tcp_sock *tp = tcp_sk(sk); | |
c1b4a7e6 | 502 | unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); |
1da177e4 LT |
503 | |
504 | hint = min(hint, tp->rcv_wnd/2); | |
505 | hint = min(hint, TCP_MIN_RCVMSS); | |
506 | hint = max(hint, TCP_MIN_MSS); | |
507 | ||
463c84b9 | 508 | inet_csk(sk)->icsk_ack.rcv_mss = hint; |
1da177e4 LT |
509 | } |
510 | ||
511 | static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) | |
512 | { | |
513 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
514 | ntohl(TCP_FLAG_ACK) | | |
515 | snd_wnd); | |
516 | } | |
517 | ||
518 | static __inline__ void tcp_fast_path_on(struct tcp_sock *tp) | |
519 | { | |
520 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
521 | } | |
522 | ||
523 | static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) | |
524 | { | |
b03efcfb | 525 | if (skb_queue_empty(&tp->out_of_order_queue) && |
1da177e4 LT |
526 | tp->rcv_wnd && |
527 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
528 | !tp->urg_data) | |
529 | tcp_fast_path_on(tp); | |
530 | } | |
531 | ||
532 | /* Compute the actual receive window we are currently advertising. | |
533 | * Rcv_nxt can be after the window if our peer push more data | |
534 | * than the offered window. | |
535 | */ | |
536 | static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) | |
537 | { | |
538 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
539 | ||
540 | if (win < 0) | |
541 | win = 0; | |
542 | return (u32) win; | |
543 | } | |
544 | ||
545 | /* Choose a new window, without checks for shrinking, and without | |
546 | * scaling applied to the result. The caller does these things | |
547 | * if necessary. This is a "raw" window selection. | |
548 | */ | |
549 | extern u32 __tcp_select_window(struct sock *sk); | |
550 | ||
551 | /* TCP timestamps are only 32-bits, this causes a slight | |
552 | * complication on 64-bit systems since we store a snapshot | |
553 | * of jiffies in the buffer control blocks below. We decidely | |
554 | * only use of the low 32-bits of jiffies and hide the ugly | |
555 | * casts with the following macro. | |
556 | */ | |
557 | #define tcp_time_stamp ((__u32)(jiffies)) | |
558 | ||
559 | /* This is what the send packet queueing engine uses to pass | |
560 | * TCP per-packet control information to the transmission | |
561 | * code. We also store the host-order sequence numbers in | |
562 | * here too. This is 36 bytes on 32-bit architectures, | |
563 | * 40 bytes on 64-bit machines, if this grows please adjust | |
564 | * skbuff.h:skbuff->cb[xxx] size appropriately. | |
565 | */ | |
566 | struct tcp_skb_cb { | |
567 | union { | |
568 | struct inet_skb_parm h4; | |
569 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
570 | struct inet6_skb_parm h6; | |
571 | #endif | |
572 | } header; /* For incoming frames */ | |
573 | __u32 seq; /* Starting sequence number */ | |
574 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
575 | __u32 when; /* used to compute rtt's */ | |
576 | __u8 flags; /* TCP header flags. */ | |
577 | ||
578 | /* NOTE: These must match up to the flags byte in a | |
579 | * real TCP header. | |
580 | */ | |
581 | #define TCPCB_FLAG_FIN 0x01 | |
582 | #define TCPCB_FLAG_SYN 0x02 | |
583 | #define TCPCB_FLAG_RST 0x04 | |
584 | #define TCPCB_FLAG_PSH 0x08 | |
585 | #define TCPCB_FLAG_ACK 0x10 | |
586 | #define TCPCB_FLAG_URG 0x20 | |
587 | #define TCPCB_FLAG_ECE 0x40 | |
588 | #define TCPCB_FLAG_CWR 0x80 | |
589 | ||
590 | __u8 sacked; /* State flags for SACK/FACK. */ | |
591 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
592 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
593 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
594 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
595 | ||
596 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
597 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) | |
598 | ||
599 | #define TCPCB_URG 0x20 /* Urgent pointer advenced here */ | |
600 | ||
601 | #define TCPCB_AT_TAIL (TCPCB_URG) | |
602 | ||
603 | __u16 urg_ptr; /* Valid w/URG flags is set. */ | |
604 | __u32 ack_seq; /* Sequence number ACK'd */ | |
605 | }; | |
606 | ||
607 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
608 | ||
609 | #include <net/tcp_ecn.h> | |
610 | ||
611 | /* Due to TSO, an SKB can be composed of multiple actual | |
612 | * packets. To keep these tracked properly, we use this. | |
613 | */ | |
614 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
615 | { | |
616 | return skb_shinfo(skb)->tso_segs; | |
617 | } | |
618 | ||
619 | /* This is valid iff tcp_skb_pcount() > 1. */ | |
620 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
621 | { | |
622 | return skb_shinfo(skb)->tso_size; | |
623 | } | |
624 | ||
625 | static inline void tcp_dec_pcount_approx(__u32 *count, | |
626 | const struct sk_buff *skb) | |
627 | { | |
628 | if (*count) { | |
629 | *count -= tcp_skb_pcount(skb); | |
630 | if ((int)*count < 0) | |
631 | *count = 0; | |
632 | } | |
633 | } | |
634 | ||
635 | static inline void tcp_packets_out_inc(struct sock *sk, | |
636 | struct tcp_sock *tp, | |
637 | const struct sk_buff *skb) | |
638 | { | |
639 | int orig = tp->packets_out; | |
640 | ||
641 | tp->packets_out += tcp_skb_pcount(skb); | |
642 | if (!orig) | |
3f421baa ACM |
643 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
644 | inet_csk(sk)->icsk_rto, TCP_RTO_MAX); | |
1da177e4 LT |
645 | } |
646 | ||
647 | static inline void tcp_packets_out_dec(struct tcp_sock *tp, | |
648 | const struct sk_buff *skb) | |
649 | { | |
650 | tp->packets_out -= tcp_skb_pcount(skb); | |
651 | } | |
652 | ||
317a76f9 SH |
653 | /* Events passed to congestion control interface */ |
654 | enum tcp_ca_event { | |
655 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
656 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
657 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
658 | CA_EVENT_FRTO, /* fast recovery timeout */ | |
659 | CA_EVENT_LOSS, /* loss timeout */ | |
660 | CA_EVENT_FAST_ACK, /* in sequence ack */ | |
661 | CA_EVENT_SLOW_ACK, /* other ack */ | |
662 | }; | |
663 | ||
664 | /* | |
665 | * Interface for adding new TCP congestion control handlers | |
666 | */ | |
667 | #define TCP_CA_NAME_MAX 16 | |
668 | struct tcp_congestion_ops { | |
669 | struct list_head list; | |
670 | ||
671 | /* initialize private data (optional) */ | |
6687e988 | 672 | void (*init)(struct sock *sk); |
317a76f9 | 673 | /* cleanup private data (optional) */ |
6687e988 | 674 | void (*release)(struct sock *sk); |
317a76f9 SH |
675 | |
676 | /* return slow start threshold (required) */ | |
6687e988 | 677 | u32 (*ssthresh)(struct sock *sk); |
317a76f9 | 678 | /* lower bound for congestion window (optional) */ |
6687e988 | 679 | u32 (*min_cwnd)(struct sock *sk); |
317a76f9 | 680 | /* do new cwnd calculation (required) */ |
6687e988 | 681 | void (*cong_avoid)(struct sock *sk, u32 ack, |
317a76f9 SH |
682 | u32 rtt, u32 in_flight, int good_ack); |
683 | /* round trip time sample per acked packet (optional) */ | |
6687e988 | 684 | void (*rtt_sample)(struct sock *sk, u32 usrtt); |
317a76f9 | 685 | /* call before changing ca_state (optional) */ |
6687e988 | 686 | void (*set_state)(struct sock *sk, u8 new_state); |
317a76f9 | 687 | /* call when cwnd event occurs (optional) */ |
6687e988 | 688 | void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); |
317a76f9 | 689 | /* new value of cwnd after loss (optional) */ |
6687e988 | 690 | u32 (*undo_cwnd)(struct sock *sk); |
317a76f9 | 691 | /* hook for packet ack accounting (optional) */ |
6687e988 | 692 | void (*pkts_acked)(struct sock *sk, u32 num_acked); |
73c1f4a0 | 693 | /* get info for inet_diag (optional) */ |
6687e988 | 694 | void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); |
317a76f9 SH |
695 | |
696 | char name[TCP_CA_NAME_MAX]; | |
697 | struct module *owner; | |
698 | }; | |
699 | ||
700 | extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
701 | extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
702 | ||
6687e988 ACM |
703 | extern void tcp_init_congestion_control(struct sock *sk); |
704 | extern void tcp_cleanup_congestion_control(struct sock *sk); | |
317a76f9 SH |
705 | extern int tcp_set_default_congestion_control(const char *name); |
706 | extern void tcp_get_default_congestion_control(char *name); | |
6687e988 | 707 | extern int tcp_set_congestion_control(struct sock *sk, const char *name); |
317a76f9 | 708 | |
5f8ef48d | 709 | extern struct tcp_congestion_ops tcp_init_congestion_ops; |
6687e988 ACM |
710 | extern u32 tcp_reno_ssthresh(struct sock *sk); |
711 | extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, | |
317a76f9 | 712 | u32 rtt, u32 in_flight, int flag); |
6687e988 | 713 | extern u32 tcp_reno_min_cwnd(struct sock *sk); |
a8acfbac | 714 | extern struct tcp_congestion_ops tcp_reno; |
317a76f9 | 715 | |
6687e988 | 716 | static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) |
317a76f9 | 717 | { |
6687e988 ACM |
718 | struct inet_connection_sock *icsk = inet_csk(sk); |
719 | ||
720 | if (icsk->icsk_ca_ops->set_state) | |
721 | icsk->icsk_ca_ops->set_state(sk, ca_state); | |
722 | icsk->icsk_ca_state = ca_state; | |
317a76f9 SH |
723 | } |
724 | ||
6687e988 | 725 | static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) |
317a76f9 | 726 | { |
6687e988 ACM |
727 | const struct inet_connection_sock *icsk = inet_csk(sk); |
728 | ||
729 | if (icsk->icsk_ca_ops->cwnd_event) | |
730 | icsk->icsk_ca_ops->cwnd_event(sk, event); | |
317a76f9 SH |
731 | } |
732 | ||
1da177e4 LT |
733 | /* This determines how many packets are "in the network" to the best |
734 | * of our knowledge. In many cases it is conservative, but where | |
735 | * detailed information is available from the receiver (via SACK | |
736 | * blocks etc.) we can make more aggressive calculations. | |
737 | * | |
738 | * Use this for decisions involving congestion control, use just | |
739 | * tp->packets_out to determine if the send queue is empty or not. | |
740 | * | |
741 | * Read this equation as: | |
742 | * | |
743 | * "Packets sent once on transmission queue" MINUS | |
744 | * "Packets left network, but not honestly ACKed yet" PLUS | |
745 | * "Packets fast retransmitted" | |
746 | */ | |
747 | static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) | |
748 | { | |
749 | return (tp->packets_out - tp->left_out + tp->retrans_out); | |
750 | } | |
751 | ||
1da177e4 LT |
752 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. |
753 | * The exception is rate halving phase, when cwnd is decreasing towards | |
754 | * ssthresh. | |
755 | */ | |
6687e988 | 756 | static inline __u32 tcp_current_ssthresh(const struct sock *sk) |
1da177e4 | 757 | { |
6687e988 ACM |
758 | const struct tcp_sock *tp = tcp_sk(sk); |
759 | if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) | |
1da177e4 LT |
760 | return tp->snd_ssthresh; |
761 | else | |
762 | return max(tp->snd_ssthresh, | |
763 | ((tp->snd_cwnd >> 1) + | |
764 | (tp->snd_cwnd >> 2))); | |
765 | } | |
766 | ||
767 | static inline void tcp_sync_left_out(struct tcp_sock *tp) | |
768 | { | |
769 | if (tp->rx_opt.sack_ok && | |
770 | (tp->sacked_out >= tp->packets_out - tp->lost_out)) | |
771 | tp->sacked_out = tp->packets_out - tp->lost_out; | |
772 | tp->left_out = tp->sacked_out + tp->lost_out; | |
773 | } | |
774 | ||
d1b04c08 | 775 | /* Set slow start threshold and cwnd not falling to slow start */ |
6687e988 | 776 | static inline void __tcp_enter_cwr(struct sock *sk) |
1da177e4 | 777 | { |
6687e988 ACM |
778 | const struct inet_connection_sock *icsk = inet_csk(sk); |
779 | struct tcp_sock *tp = tcp_sk(sk); | |
780 | ||
1da177e4 | 781 | tp->undo_marker = 0; |
6687e988 | 782 | tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); |
1da177e4 LT |
783 | tp->snd_cwnd = min(tp->snd_cwnd, |
784 | tcp_packets_in_flight(tp) + 1U); | |
785 | tp->snd_cwnd_cnt = 0; | |
786 | tp->high_seq = tp->snd_nxt; | |
787 | tp->snd_cwnd_stamp = tcp_time_stamp; | |
788 | TCP_ECN_queue_cwr(tp); | |
789 | } | |
790 | ||
6687e988 | 791 | static inline void tcp_enter_cwr(struct sock *sk) |
1da177e4 | 792 | { |
6687e988 ACM |
793 | struct tcp_sock *tp = tcp_sk(sk); |
794 | ||
1da177e4 | 795 | tp->prior_ssthresh = 0; |
6687e988 ACM |
796 | if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { |
797 | __tcp_enter_cwr(sk); | |
798 | tcp_set_ca_state(sk, TCP_CA_CWR); | |
1da177e4 LT |
799 | } |
800 | } | |
801 | ||
802 | extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); | |
803 | ||
804 | /* Slow start with delack produces 3 packets of burst, so that | |
805 | * it is safe "de facto". | |
806 | */ | |
807 | static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) | |
808 | { | |
809 | return 3; | |
810 | } | |
811 | ||
1da177e4 LT |
812 | static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, |
813 | const struct sk_buff *skb) | |
814 | { | |
815 | if (skb->len < mss) | |
816 | tp->snd_sml = TCP_SKB_CB(skb)->end_seq; | |
817 | } | |
818 | ||
1da177e4 LT |
819 | static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) |
820 | { | |
463c84b9 ACM |
821 | const struct inet_connection_sock *icsk = inet_csk(sk); |
822 | if (!tp->packets_out && !icsk->icsk_pending) | |
3f421baa ACM |
823 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, |
824 | icsk->icsk_rto, TCP_RTO_MAX); | |
1da177e4 LT |
825 | } |
826 | ||
1da177e4 LT |
827 | static __inline__ void tcp_push_pending_frames(struct sock *sk, |
828 | struct tcp_sock *tp) | |
829 | { | |
830 | __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); | |
831 | } | |
832 | ||
1da177e4 LT |
833 | static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) |
834 | { | |
835 | tp->snd_wl1 = seq; | |
836 | } | |
837 | ||
838 | static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) | |
839 | { | |
840 | tp->snd_wl1 = seq; | |
841 | } | |
842 | ||
1da177e4 LT |
843 | /* |
844 | * Calculate(/check) TCP checksum | |
845 | */ | |
846 | static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, | |
847 | unsigned long saddr, unsigned long daddr, | |
848 | unsigned long base) | |
849 | { | |
850 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
851 | } | |
852 | ||
853 | static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) | |
854 | { | |
855 | return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); | |
856 | } | |
857 | ||
858 | static __inline__ int tcp_checksum_complete(struct sk_buff *skb) | |
859 | { | |
860 | return skb->ip_summed != CHECKSUM_UNNECESSARY && | |
861 | __tcp_checksum_complete(skb); | |
862 | } | |
863 | ||
864 | /* Prequeue for VJ style copy to user, combined with checksumming. */ | |
865 | ||
866 | static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) | |
867 | { | |
868 | tp->ucopy.task = NULL; | |
869 | tp->ucopy.len = 0; | |
870 | tp->ucopy.memory = 0; | |
871 | skb_queue_head_init(&tp->ucopy.prequeue); | |
872 | } | |
873 | ||
874 | /* Packet is added to VJ-style prequeue for processing in process | |
875 | * context, if a reader task is waiting. Apparently, this exciting | |
876 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) | |
877 | * failed somewhere. Latency? Burstiness? Well, at least now we will | |
878 | * see, why it failed. 8)8) --ANK | |
879 | * | |
880 | * NOTE: is this not too big to inline? | |
881 | */ | |
882 | static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) | |
883 | { | |
884 | struct tcp_sock *tp = tcp_sk(sk); | |
885 | ||
886 | if (!sysctl_tcp_low_latency && tp->ucopy.task) { | |
887 | __skb_queue_tail(&tp->ucopy.prequeue, skb); | |
888 | tp->ucopy.memory += skb->truesize; | |
889 | if (tp->ucopy.memory > sk->sk_rcvbuf) { | |
890 | struct sk_buff *skb1; | |
891 | ||
892 | BUG_ON(sock_owned_by_user(sk)); | |
893 | ||
894 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { | |
895 | sk->sk_backlog_rcv(sk, skb1); | |
896 | NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); | |
897 | } | |
898 | ||
899 | tp->ucopy.memory = 0; | |
900 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { | |
901 | wake_up_interruptible(sk->sk_sleep); | |
463c84b9 ACM |
902 | if (!inet_csk_ack_scheduled(sk)) |
903 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
3f421baa ACM |
904 | (3 * TCP_RTO_MIN) / 4, |
905 | TCP_RTO_MAX); | |
1da177e4 LT |
906 | } |
907 | return 1; | |
908 | } | |
909 | return 0; | |
910 | } | |
911 | ||
912 | ||
913 | #undef STATE_TRACE | |
914 | ||
915 | #ifdef STATE_TRACE | |
916 | static const char *statename[]={ | |
917 | "Unused","Established","Syn Sent","Syn Recv", | |
918 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
919 | "Close Wait","Last ACK","Listen","Closing" | |
920 | }; | |
921 | #endif | |
922 | ||
923 | static __inline__ void tcp_set_state(struct sock *sk, int state) | |
924 | { | |
925 | int oldstate = sk->sk_state; | |
926 | ||
927 | switch (state) { | |
928 | case TCP_ESTABLISHED: | |
929 | if (oldstate != TCP_ESTABLISHED) | |
930 | TCP_INC_STATS(TCP_MIB_CURRESTAB); | |
931 | break; | |
932 | ||
933 | case TCP_CLOSE: | |
934 | if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) | |
935 | TCP_INC_STATS(TCP_MIB_ESTABRESETS); | |
936 | ||
937 | sk->sk_prot->unhash(sk); | |
463c84b9 | 938 | if (inet_csk(sk)->icsk_bind_hash && |
1da177e4 | 939 | !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) |
2d8c4ce5 | 940 | inet_put_port(&tcp_hashinfo, sk); |
1da177e4 LT |
941 | /* fall through */ |
942 | default: | |
943 | if (oldstate==TCP_ESTABLISHED) | |
944 | TCP_DEC_STATS(TCP_MIB_CURRESTAB); | |
945 | } | |
946 | ||
947 | /* Change state AFTER socket is unhashed to avoid closed | |
948 | * socket sitting in hash tables. | |
949 | */ | |
950 | sk->sk_state = state; | |
951 | ||
952 | #ifdef STATE_TRACE | |
953 | SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); | |
954 | #endif | |
955 | } | |
956 | ||
957 | static __inline__ void tcp_done(struct sock *sk) | |
958 | { | |
959 | tcp_set_state(sk, TCP_CLOSE); | |
960 | tcp_clear_xmit_timers(sk); | |
961 | ||
962 | sk->sk_shutdown = SHUTDOWN_MASK; | |
963 | ||
964 | if (!sock_flag(sk, SOCK_DEAD)) | |
965 | sk->sk_state_change(sk); | |
966 | else | |
0a5578cf | 967 | inet_csk_destroy_sock(sk); |
1da177e4 LT |
968 | } |
969 | ||
970 | static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) | |
971 | { | |
972 | rx_opt->dsack = 0; | |
973 | rx_opt->eff_sacks = 0; | |
974 | rx_opt->num_sacks = 0; | |
975 | } | |
976 | ||
977 | static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) | |
978 | { | |
979 | if (tp->rx_opt.tstamp_ok) { | |
980 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | | |
981 | (TCPOPT_NOP << 16) | | |
982 | (TCPOPT_TIMESTAMP << 8) | | |
983 | TCPOLEN_TIMESTAMP); | |
984 | *ptr++ = htonl(tstamp); | |
985 | *ptr++ = htonl(tp->rx_opt.ts_recent); | |
986 | } | |
987 | if (tp->rx_opt.eff_sacks) { | |
988 | struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; | |
989 | int this_sack; | |
990 | ||
991 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | | |
992 | (TCPOPT_NOP << 16) | | |
993 | (TCPOPT_SACK << 8) | | |
994 | (TCPOLEN_SACK_BASE + | |
995 | (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK))); | |
996 | for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { | |
997 | *ptr++ = htonl(sp[this_sack].start_seq); | |
998 | *ptr++ = htonl(sp[this_sack].end_seq); | |
999 | } | |
1000 | if (tp->rx_opt.dsack) { | |
1001 | tp->rx_opt.dsack = 0; | |
1002 | tp->rx_opt.eff_sacks--; | |
1003 | } | |
1004 | } | |
1005 | } | |
1006 | ||
1007 | /* Construct a tcp options header for a SYN or SYN_ACK packet. | |
1008 | * If this is every changed make sure to change the definition of | |
1009 | * MAX_SYN_SIZE to match the new maximum number of options that you | |
1010 | * can generate. | |
1011 | */ | |
1012 | static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, | |
1013 | int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) | |
1014 | { | |
1015 | /* We always get an MSS option. | |
1016 | * The option bytes which will be seen in normal data | |
1017 | * packets should timestamps be used, must be in the MSS | |
1018 | * advertised. But we subtract them from tp->mss_cache so | |
1019 | * that calculations in tcp_sendmsg are simpler etc. | |
1020 | * So account for this fact here if necessary. If we | |
1021 | * don't do this correctly, as a receiver we won't | |
1022 | * recognize data packets as being full sized when we | |
1023 | * should, and thus we won't abide by the delayed ACK | |
1024 | * rules correctly. | |
1025 | * SACKs don't matter, we never delay an ACK when we | |
1026 | * have any of those going out. | |
1027 | */ | |
1028 | *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); | |
1029 | if (ts) { | |
1030 | if(sack) | |
1031 | *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | | |
1032 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1033 | else | |
1034 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1035 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1036 | *ptr++ = htonl(tstamp); /* TSVAL */ | |
1037 | *ptr++ = htonl(ts_recent); /* TSECR */ | |
1038 | } else if(sack) | |
1039 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1040 | (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); | |
1041 | if (offer_wscale) | |
1042 | *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); | |
1043 | } | |
1044 | ||
1045 | /* Determine a window scaling and initial window to offer. */ | |
1046 | extern void tcp_select_initial_window(int __space, __u32 mss, | |
1047 | __u32 *rcv_wnd, __u32 *window_clamp, | |
1048 | int wscale_ok, __u8 *rcv_wscale); | |
1049 | ||
1050 | static inline int tcp_win_from_space(int space) | |
1051 | { | |
1052 | return sysctl_tcp_adv_win_scale<=0 ? | |
1053 | (space>>(-sysctl_tcp_adv_win_scale)) : | |
1054 | space - (space>>sysctl_tcp_adv_win_scale); | |
1055 | } | |
1056 | ||
1057 | /* Note: caller must be prepared to deal with negative returns */ | |
1058 | static inline int tcp_space(const struct sock *sk) | |
1059 | { | |
1060 | return tcp_win_from_space(sk->sk_rcvbuf - | |
1061 | atomic_read(&sk->sk_rmem_alloc)); | |
1062 | } | |
1063 | ||
1064 | static inline int tcp_full_space(const struct sock *sk) | |
1065 | { | |
1066 | return tcp_win_from_space(sk->sk_rcvbuf); | |
1067 | } | |
1068 | ||
60236fdd | 1069 | static __inline__ void tcp_openreq_init(struct request_sock *req, |
1da177e4 LT |
1070 | struct tcp_options_received *rx_opt, |
1071 | struct sk_buff *skb) | |
1072 | { | |
2e6599cb ACM |
1073 | struct inet_request_sock *ireq = inet_rsk(req); |
1074 | ||
1da177e4 | 1075 | req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
2e6599cb | 1076 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
1da177e4 LT |
1077 | req->mss = rx_opt->mss_clamp; |
1078 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; | |
2e6599cb ACM |
1079 | ireq->tstamp_ok = rx_opt->tstamp_ok; |
1080 | ireq->sack_ok = rx_opt->sack_ok; | |
1081 | ireq->snd_wscale = rx_opt->snd_wscale; | |
1082 | ireq->wscale_ok = rx_opt->wscale_ok; | |
1083 | ireq->acked = 0; | |
1084 | ireq->ecn_ok = 0; | |
1085 | ireq->rmt_port = skb->h.th->source; | |
1da177e4 LT |
1086 | } |
1087 | ||
1088 | extern void tcp_enter_memory_pressure(void); | |
1089 | ||
1da177e4 LT |
1090 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) |
1091 | { | |
1092 | return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; | |
1093 | } | |
1094 | ||
1095 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1096 | { | |
1097 | return tp->keepalive_time ? : sysctl_tcp_keepalive_time; | |
1098 | } | |
1099 | ||
463c84b9 | 1100 | static inline int tcp_fin_time(const struct sock *sk) |
1da177e4 | 1101 | { |
463c84b9 ACM |
1102 | int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; |
1103 | const int rto = inet_csk(sk)->icsk_rto; | |
1da177e4 | 1104 | |
463c84b9 ACM |
1105 | if (fin_timeout < (rto << 2) - (rto >> 1)) |
1106 | fin_timeout = (rto << 2) - (rto >> 1); | |
1da177e4 LT |
1107 | |
1108 | return fin_timeout; | |
1109 | } | |
1110 | ||
1111 | static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) | |
1112 | { | |
1113 | if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) | |
1114 | return 0; | |
1115 | if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) | |
1116 | return 0; | |
1117 | ||
1118 | /* RST segments are not recommended to carry timestamp, | |
1119 | and, if they do, it is recommended to ignore PAWS because | |
1120 | "their cleanup function should take precedence over timestamps." | |
1121 | Certainly, it is mistake. It is necessary to understand the reasons | |
1122 | of this constraint to relax it: if peer reboots, clock may go | |
1123 | out-of-sync and half-open connections will not be reset. | |
1124 | Actually, the problem would be not existing if all | |
1125 | the implementations followed draft about maintaining clock | |
1126 | via reboots. Linux-2.2 DOES NOT! | |
1127 | ||
1128 | However, we can relax time bounds for RST segments to MSL. | |
1129 | */ | |
1130 | if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) | |
1131 | return 0; | |
1132 | return 1; | |
1133 | } | |
1134 | ||
1da177e4 LT |
1135 | #define TCP_CHECK_TIMER(sk) do { } while (0) |
1136 | ||
1137 | static inline int tcp_use_frto(const struct sock *sk) | |
1138 | { | |
1139 | const struct tcp_sock *tp = tcp_sk(sk); | |
1140 | ||
1141 | /* F-RTO must be activated in sysctl and there must be some | |
1142 | * unsent new data, and the advertised window should allow | |
1143 | * sending it. | |
1144 | */ | |
1145 | return (sysctl_tcp_frto && sk->sk_send_head && | |
1146 | !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, | |
1147 | tp->snd_una + tp->snd_wnd)); | |
1148 | } | |
1149 | ||
1150 | static inline void tcp_mib_init(void) | |
1151 | { | |
1152 | /* See RFC 2012 */ | |
1153 | TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); | |
1154 | TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1155 | TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1156 | TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); | |
1157 | } | |
1158 | ||
1159 | /* /proc */ | |
1160 | enum tcp_seq_states { | |
1161 | TCP_SEQ_STATE_LISTENING, | |
1162 | TCP_SEQ_STATE_OPENREQ, | |
1163 | TCP_SEQ_STATE_ESTABLISHED, | |
1164 | TCP_SEQ_STATE_TIME_WAIT, | |
1165 | }; | |
1166 | ||
1167 | struct tcp_seq_afinfo { | |
1168 | struct module *owner; | |
1169 | char *name; | |
1170 | sa_family_t family; | |
1171 | int (*seq_show) (struct seq_file *m, void *v); | |
1172 | struct file_operations *seq_fops; | |
1173 | }; | |
1174 | ||
1175 | struct tcp_iter_state { | |
1176 | sa_family_t family; | |
1177 | enum tcp_seq_states state; | |
1178 | struct sock *syn_wait_sk; | |
1179 | int bucket, sbucket, num, uid; | |
1180 | struct seq_operations seq_ops; | |
1181 | }; | |
1182 | ||
1183 | extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); | |
1184 | extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); | |
1185 | ||
1da177e4 | 1186 | #endif /* _TCP_H */ |