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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 | ||
24 | /* Cancel timers, when they are not required. */ | |
25 | #undef TCP_CLEAR_TIMERS | |
26 | ||
27 | #include <linux/config.h> | |
28 | #include <linux/list.h> | |
29 | #include <linux/tcp.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/cache.h> | |
32 | #include <linux/percpu.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> | |
39 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
40 | #include <linux/ipv6.h> | |
41 | #endif | |
42 | #include <linux/seq_file.h> | |
43 | ||
6e04e021 | 44 | extern struct inet_hashinfo tcp_hashinfo; |
1da177e4 | 45 | |
1da177e4 LT |
46 | #if (BITS_PER_LONG == 64) |
47 | #define TCP_ADDRCMP_ALIGN_BYTES 8 | |
48 | #else | |
49 | #define TCP_ADDRCMP_ALIGN_BYTES 4 | |
50 | #endif | |
51 | ||
52 | /* This is a TIME_WAIT bucket. It works around the memory consumption | |
53 | * problems of sockets in such a state on heavily loaded servers, but | |
54 | * without violating the protocol specification. | |
55 | */ | |
56 | struct tcp_tw_bucket { | |
57 | /* | |
58 | * Now struct sock also uses sock_common, so please just | |
59 | * don't add nothing before this first member (__tw_common) --acme | |
60 | */ | |
61 | struct sock_common __tw_common; | |
62 | #define tw_family __tw_common.skc_family | |
63 | #define tw_state __tw_common.skc_state | |
64 | #define tw_reuse __tw_common.skc_reuse | |
65 | #define tw_bound_dev_if __tw_common.skc_bound_dev_if | |
66 | #define tw_node __tw_common.skc_node | |
67 | #define tw_bind_node __tw_common.skc_bind_node | |
68 | #define tw_refcnt __tw_common.skc_refcnt | |
69 | volatile unsigned char tw_substate; | |
70 | unsigned char tw_rcv_wscale; | |
71 | __u16 tw_sport; | |
72 | /* Socket demultiplex comparisons on incoming packets. */ | |
73 | /* these five are in inet_sock */ | |
74 | __u32 tw_daddr | |
75 | __attribute__((aligned(TCP_ADDRCMP_ALIGN_BYTES))); | |
76 | __u32 tw_rcv_saddr; | |
77 | __u16 tw_dport; | |
78 | __u16 tw_num; | |
79 | /* And these are ours. */ | |
80 | int tw_hashent; | |
81 | int tw_timeout; | |
82 | __u32 tw_rcv_nxt; | |
83 | __u32 tw_snd_nxt; | |
84 | __u32 tw_rcv_wnd; | |
85 | __u32 tw_ts_recent; | |
86 | long tw_ts_recent_stamp; | |
87 | unsigned long tw_ttd; | |
0f7ff927 | 88 | struct inet_bind_bucket *tw_tb; |
1da177e4 LT |
89 | struct hlist_node tw_death_node; |
90 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
91 | struct in6_addr tw_v6_daddr; | |
92 | struct in6_addr tw_v6_rcv_saddr; | |
93 | int tw_v6_ipv6only; | |
94 | #endif | |
95 | }; | |
96 | ||
97 | static __inline__ void tw_add_node(struct tcp_tw_bucket *tw, | |
98 | struct hlist_head *list) | |
99 | { | |
100 | hlist_add_head(&tw->tw_node, list); | |
101 | } | |
102 | ||
103 | static __inline__ void tw_add_bind_node(struct tcp_tw_bucket *tw, | |
104 | struct hlist_head *list) | |
105 | { | |
106 | hlist_add_head(&tw->tw_bind_node, list); | |
107 | } | |
108 | ||
109 | static inline int tw_dead_hashed(struct tcp_tw_bucket *tw) | |
110 | { | |
111 | return tw->tw_death_node.pprev != NULL; | |
112 | } | |
113 | ||
114 | static __inline__ void tw_dead_node_init(struct tcp_tw_bucket *tw) | |
115 | { | |
116 | tw->tw_death_node.pprev = NULL; | |
117 | } | |
118 | ||
119 | static __inline__ void __tw_del_dead_node(struct tcp_tw_bucket *tw) | |
120 | { | |
121 | __hlist_del(&tw->tw_death_node); | |
122 | tw_dead_node_init(tw); | |
123 | } | |
124 | ||
125 | static __inline__ int tw_del_dead_node(struct tcp_tw_bucket *tw) | |
126 | { | |
127 | if (tw_dead_hashed(tw)) { | |
128 | __tw_del_dead_node(tw); | |
129 | return 1; | |
130 | } | |
131 | return 0; | |
132 | } | |
133 | ||
134 | #define tw_for_each(tw, node, head) \ | |
135 | hlist_for_each_entry(tw, node, head, tw_node) | |
136 | ||
137 | #define tw_for_each_inmate(tw, node, jail) \ | |
138 | hlist_for_each_entry(tw, node, jail, tw_death_node) | |
139 | ||
140 | #define tw_for_each_inmate_safe(tw, node, safe, jail) \ | |
141 | hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node) | |
142 | ||
143 | #define tcptw_sk(__sk) ((struct tcp_tw_bucket *)(__sk)) | |
144 | ||
145 | static inline u32 tcp_v4_rcv_saddr(const struct sock *sk) | |
146 | { | |
147 | return likely(sk->sk_state != TCP_TIME_WAIT) ? | |
148 | inet_sk(sk)->rcv_saddr : tcptw_sk(sk)->tw_rcv_saddr; | |
149 | } | |
150 | ||
151 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
152 | static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk) | |
153 | { | |
154 | return likely(sk->sk_state != TCP_TIME_WAIT) ? | |
155 | &inet6_sk(sk)->rcv_saddr : &tcptw_sk(sk)->tw_v6_rcv_saddr; | |
156 | } | |
157 | ||
158 | static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk) | |
159 | { | |
160 | return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL; | |
161 | } | |
162 | ||
163 | #define tcptw_sk_ipv6only(__sk) (tcptw_sk(__sk)->tw_v6_ipv6only) | |
164 | ||
165 | static inline int tcp_v6_ipv6only(const struct sock *sk) | |
166 | { | |
167 | return likely(sk->sk_state != TCP_TIME_WAIT) ? | |
168 | ipv6_only_sock(sk) : tcptw_sk_ipv6only(sk); | |
169 | } | |
170 | #else | |
171 | # define __tcp_v6_rcv_saddr(__sk) NULL | |
172 | # define tcp_v6_rcv_saddr(__sk) NULL | |
173 | # define tcptw_sk_ipv6only(__sk) 0 | |
174 | # define tcp_v6_ipv6only(__sk) 0 | |
175 | #endif | |
176 | ||
177 | extern kmem_cache_t *tcp_timewait_cachep; | |
178 | ||
179 | static inline void tcp_tw_put(struct tcp_tw_bucket *tw) | |
180 | { | |
181 | if (atomic_dec_and_test(&tw->tw_refcnt)) { | |
e6848976 | 182 | #ifdef SOCK_REFCNT_DEBUG |
1da177e4 LT |
183 | printk(KERN_DEBUG "tw_bucket %p released\n", tw); |
184 | #endif | |
185 | kmem_cache_free(tcp_timewait_cachep, tw); | |
186 | } | |
187 | } | |
188 | ||
189 | extern atomic_t tcp_orphan_count; | |
190 | extern int tcp_tw_count; | |
191 | extern void tcp_time_wait(struct sock *sk, int state, int timeo); | |
192 | extern void tcp_tw_deschedule(struct tcp_tw_bucket *tw); | |
193 | ||
194 | ||
195 | /* Socket demux engine toys. */ | |
196 | #ifdef __BIG_ENDIAN | |
197 | #define TCP_COMBINED_PORTS(__sport, __dport) \ | |
198 | (((__u32)(__sport)<<16) | (__u32)(__dport)) | |
199 | #else /* __LITTLE_ENDIAN */ | |
200 | #define TCP_COMBINED_PORTS(__sport, __dport) \ | |
201 | (((__u32)(__dport)<<16) | (__u32)(__sport)) | |
202 | #endif | |
203 | ||
204 | #if (BITS_PER_LONG == 64) | |
205 | #ifdef __BIG_ENDIAN | |
206 | #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \ | |
207 | __u64 __name = (((__u64)(__saddr))<<32)|((__u64)(__daddr)); | |
208 | #else /* __LITTLE_ENDIAN */ | |
209 | #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \ | |
210 | __u64 __name = (((__u64)(__daddr))<<32)|((__u64)(__saddr)); | |
211 | #endif /* __BIG_ENDIAN */ | |
212 | #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
213 | (((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \ | |
214 | ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ | |
215 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
216 | #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
217 | (((*((__u64 *)&(tcptw_sk(__sk)->tw_daddr))) == (__cookie)) && \ | |
218 | ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \ | |
219 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
220 | #else /* 32-bit arch */ | |
221 | #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) | |
222 | #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
223 | ((inet_sk(__sk)->daddr == (__saddr)) && \ | |
224 | (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ | |
225 | ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ | |
226 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
227 | #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ | |
228 | ((tcptw_sk(__sk)->tw_daddr == (__saddr)) && \ | |
229 | (tcptw_sk(__sk)->tw_rcv_saddr == (__daddr)) && \ | |
230 | ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \ | |
231 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
232 | #endif /* 64-bit arch */ | |
233 | ||
234 | #define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \ | |
235 | (((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ | |
236 | ((__sk)->sk_family == AF_INET6) && \ | |
237 | ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr)) && \ | |
238 | ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \ | |
239 | (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) | |
240 | ||
1da177e4 LT |
241 | #define MAX_TCP_HEADER (128 + MAX_HEADER) |
242 | ||
243 | /* | |
244 | * Never offer a window over 32767 without using window scaling. Some | |
245 | * poor stacks do signed 16bit maths! | |
246 | */ | |
247 | #define MAX_TCP_WINDOW 32767U | |
248 | ||
249 | /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ | |
250 | #define TCP_MIN_MSS 88U | |
251 | ||
252 | /* Minimal RCV_MSS. */ | |
253 | #define TCP_MIN_RCVMSS 536U | |
254 | ||
255 | /* After receiving this amount of duplicate ACKs fast retransmit starts. */ | |
256 | #define TCP_FASTRETRANS_THRESH 3 | |
257 | ||
258 | /* Maximal reordering. */ | |
259 | #define TCP_MAX_REORDERING 127 | |
260 | ||
261 | /* Maximal number of ACKs sent quickly to accelerate slow-start. */ | |
262 | #define TCP_MAX_QUICKACKS 16U | |
263 | ||
264 | /* urg_data states */ | |
265 | #define TCP_URG_VALID 0x0100 | |
266 | #define TCP_URG_NOTYET 0x0200 | |
267 | #define TCP_URG_READ 0x0400 | |
268 | ||
269 | #define TCP_RETR1 3 /* | |
270 | * This is how many retries it does before it | |
271 | * tries to figure out if the gateway is | |
272 | * down. Minimal RFC value is 3; it corresponds | |
273 | * to ~3sec-8min depending on RTO. | |
274 | */ | |
275 | ||
276 | #define TCP_RETR2 15 /* | |
277 | * This should take at least | |
278 | * 90 minutes to time out. | |
279 | * RFC1122 says that the limit is 100 sec. | |
280 | * 15 is ~13-30min depending on RTO. | |
281 | */ | |
282 | ||
283 | #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a | |
284 | * connection: ~180sec is RFC minumum */ | |
285 | ||
286 | #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a | |
287 | * connection: ~180sec is RFC minumum */ | |
288 | ||
289 | ||
290 | #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned | |
291 | * socket. 7 is ~50sec-16min. | |
292 | */ | |
293 | ||
294 | ||
295 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT | |
296 | * state, about 60 seconds */ | |
297 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
298 | /* BSD style FIN_WAIT2 deadlock breaker. | |
299 | * It used to be 3min, new value is 60sec, | |
300 | * to combine FIN-WAIT-2 timeout with | |
301 | * TIME-WAIT timer. | |
302 | */ | |
303 | ||
304 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
305 | #if HZ >= 100 | |
306 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
307 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
308 | #else | |
309 | #define TCP_DELACK_MIN 4U | |
310 | #define TCP_ATO_MIN 4U | |
311 | #endif | |
312 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
313 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
314 | #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ | |
315 | ||
316 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
317 | * for local resources. | |
318 | */ | |
319 | ||
320 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
321 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
322 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
323 | ||
324 | #define MAX_TCP_KEEPIDLE 32767 | |
325 | #define MAX_TCP_KEEPINTVL 32767 | |
326 | #define MAX_TCP_KEEPCNT 127 | |
327 | #define MAX_TCP_SYNCNT 127 | |
328 | ||
329 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
330 | #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ | |
331 | ||
332 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
333 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
334 | * after this time. It should be equal | |
335 | * (or greater than) TCP_TIMEWAIT_LEN | |
336 | * to provide reliability equal to one | |
337 | * provided by timewait state. | |
338 | */ | |
339 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
340 | * timestamps. It must be less than | |
341 | * minimal timewait lifetime. | |
342 | */ | |
343 | ||
344 | #define TCP_TW_RECYCLE_SLOTS_LOG 5 | |
345 | #define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG) | |
346 | ||
347 | /* If time > 4sec, it is "slow" path, no recycling is required, | |
348 | so that we select tick to get range about 4 seconds. | |
349 | */ | |
350 | ||
351 | #if HZ <= 16 || HZ > 4096 | |
352 | # error Unsupported: HZ <= 16 or HZ > 4096 | |
353 | #elif HZ <= 32 | |
354 | # define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
355 | #elif HZ <= 64 | |
356 | # define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
357 | #elif HZ <= 128 | |
358 | # define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
359 | #elif HZ <= 256 | |
360 | # define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
361 | #elif HZ <= 512 | |
362 | # define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
363 | #elif HZ <= 1024 | |
364 | # define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
365 | #elif HZ <= 2048 | |
366 | # define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
367 | #else | |
368 | # define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG) | |
369 | #endif | |
1da177e4 LT |
370 | /* |
371 | * TCP option | |
372 | */ | |
373 | ||
374 | #define TCPOPT_NOP 1 /* Padding */ | |
375 | #define TCPOPT_EOL 0 /* End of options */ | |
376 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
377 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
378 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
379 | #define TCPOPT_SACK 5 /* SACK Block */ | |
380 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
381 | ||
382 | /* | |
383 | * TCP option lengths | |
384 | */ | |
385 | ||
386 | #define TCPOLEN_MSS 4 | |
387 | #define TCPOLEN_WINDOW 3 | |
388 | #define TCPOLEN_SACK_PERM 2 | |
389 | #define TCPOLEN_TIMESTAMP 10 | |
390 | ||
391 | /* But this is what stacks really send out. */ | |
392 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
393 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
394 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
395 | #define TCPOLEN_SACK_BASE 2 | |
396 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
397 | #define TCPOLEN_SACK_PERBLOCK 8 | |
398 | ||
399 | #define TCP_TIME_RETRANS 1 /* Retransmit timer */ | |
400 | #define TCP_TIME_DACK 2 /* Delayed ack timer */ | |
401 | #define TCP_TIME_PROBE0 3 /* Zero window probe timer */ | |
402 | #define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */ | |
403 | ||
404 | /* Flags in tp->nonagle */ | |
405 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
406 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
407 | #define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */ | |
408 | ||
409 | /* sysctl variables for tcp */ | |
1da177e4 LT |
410 | extern int sysctl_tcp_timestamps; |
411 | extern int sysctl_tcp_window_scaling; | |
412 | extern int sysctl_tcp_sack; | |
413 | extern int sysctl_tcp_fin_timeout; | |
414 | extern int sysctl_tcp_tw_recycle; | |
415 | extern int sysctl_tcp_keepalive_time; | |
416 | extern int sysctl_tcp_keepalive_probes; | |
417 | extern int sysctl_tcp_keepalive_intvl; | |
418 | extern int sysctl_tcp_syn_retries; | |
419 | extern int sysctl_tcp_synack_retries; | |
420 | extern int sysctl_tcp_retries1; | |
421 | extern int sysctl_tcp_retries2; | |
422 | extern int sysctl_tcp_orphan_retries; | |
423 | extern int sysctl_tcp_syncookies; | |
424 | extern int sysctl_tcp_retrans_collapse; | |
425 | extern int sysctl_tcp_stdurg; | |
426 | extern int sysctl_tcp_rfc1337; | |
427 | extern int sysctl_tcp_abort_on_overflow; | |
428 | extern int sysctl_tcp_max_orphans; | |
429 | extern int sysctl_tcp_max_tw_buckets; | |
430 | extern int sysctl_tcp_fack; | |
431 | extern int sysctl_tcp_reordering; | |
432 | extern int sysctl_tcp_ecn; | |
433 | extern int sysctl_tcp_dsack; | |
434 | extern int sysctl_tcp_mem[3]; | |
435 | extern int sysctl_tcp_wmem[3]; | |
436 | extern int sysctl_tcp_rmem[3]; | |
437 | extern int sysctl_tcp_app_win; | |
438 | extern int sysctl_tcp_adv_win_scale; | |
439 | extern int sysctl_tcp_tw_reuse; | |
440 | extern int sysctl_tcp_frto; | |
441 | extern int sysctl_tcp_low_latency; | |
1da177e4 | 442 | extern int sysctl_tcp_nometrics_save; |
1da177e4 LT |
443 | extern int sysctl_tcp_moderate_rcvbuf; |
444 | extern int sysctl_tcp_tso_win_divisor; | |
445 | ||
446 | extern atomic_t tcp_memory_allocated; | |
447 | extern atomic_t tcp_sockets_allocated; | |
448 | extern int tcp_memory_pressure; | |
449 | ||
1da177e4 LT |
450 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) |
451 | #define TCP_INET_FAMILY(fam) ((fam) == AF_INET) | |
452 | #else | |
453 | #define TCP_INET_FAMILY(fam) 1 | |
454 | #endif | |
455 | ||
456 | /* | |
457 | * Pointers to address related TCP functions | |
458 | * (i.e. things that depend on the address family) | |
459 | */ | |
460 | ||
461 | struct tcp_func { | |
462 | int (*queue_xmit) (struct sk_buff *skb, | |
463 | int ipfragok); | |
464 | ||
465 | void (*send_check) (struct sock *sk, | |
466 | struct tcphdr *th, | |
467 | int len, | |
468 | struct sk_buff *skb); | |
469 | ||
470 | int (*rebuild_header) (struct sock *sk); | |
471 | ||
472 | int (*conn_request) (struct sock *sk, | |
473 | struct sk_buff *skb); | |
474 | ||
475 | struct sock * (*syn_recv_sock) (struct sock *sk, | |
476 | struct sk_buff *skb, | |
60236fdd | 477 | struct request_sock *req, |
1da177e4 LT |
478 | struct dst_entry *dst); |
479 | ||
480 | int (*remember_stamp) (struct sock *sk); | |
481 | ||
482 | __u16 net_header_len; | |
483 | ||
484 | int (*setsockopt) (struct sock *sk, | |
485 | int level, | |
486 | int optname, | |
487 | char __user *optval, | |
488 | int optlen); | |
489 | ||
490 | int (*getsockopt) (struct sock *sk, | |
491 | int level, | |
492 | int optname, | |
493 | char __user *optval, | |
494 | int __user *optlen); | |
495 | ||
496 | ||
497 | void (*addr2sockaddr) (struct sock *sk, | |
498 | struct sockaddr *); | |
499 | ||
500 | int sockaddr_len; | |
501 | }; | |
502 | ||
503 | /* | |
504 | * The next routines deal with comparing 32 bit unsigned ints | |
505 | * and worry about wraparound (automatic with unsigned arithmetic). | |
506 | */ | |
507 | ||
508 | static inline int before(__u32 seq1, __u32 seq2) | |
509 | { | |
510 | return (__s32)(seq1-seq2) < 0; | |
511 | } | |
512 | ||
513 | static inline int after(__u32 seq1, __u32 seq2) | |
514 | { | |
515 | return (__s32)(seq2-seq1) < 0; | |
516 | } | |
517 | ||
518 | ||
519 | /* is s2<=s1<=s3 ? */ | |
520 | static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) | |
521 | { | |
522 | return seq3 - seq2 >= seq1 - seq2; | |
523 | } | |
524 | ||
525 | ||
526 | extern struct proto tcp_prot; | |
527 | ||
528 | DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); | |
529 | #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) | |
530 | #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) | |
531 | #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) | |
532 | #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) | |
533 | #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) | |
534 | #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) | |
535 | ||
1da177e4 LT |
536 | extern void tcp_v4_err(struct sk_buff *skb, u32); |
537 | ||
538 | extern void tcp_shutdown (struct sock *sk, int how); | |
539 | ||
540 | extern int tcp_v4_rcv(struct sk_buff *skb); | |
541 | ||
542 | extern int tcp_v4_remember_stamp(struct sock *sk); | |
543 | ||
544 | extern int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw); | |
545 | ||
546 | extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, | |
547 | struct msghdr *msg, size_t size); | |
548 | extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); | |
549 | ||
550 | extern int tcp_ioctl(struct sock *sk, | |
551 | int cmd, | |
552 | unsigned long arg); | |
553 | ||
554 | extern int tcp_rcv_state_process(struct sock *sk, | |
555 | struct sk_buff *skb, | |
556 | struct tcphdr *th, | |
557 | unsigned len); | |
558 | ||
559 | extern int tcp_rcv_established(struct sock *sk, | |
560 | struct sk_buff *skb, | |
561 | struct tcphdr *th, | |
562 | unsigned len); | |
563 | ||
564 | extern void tcp_rcv_space_adjust(struct sock *sk); | |
565 | ||
566 | enum tcp_ack_state_t | |
567 | { | |
568 | TCP_ACK_SCHED = 1, | |
569 | TCP_ACK_TIMER = 2, | |
570 | TCP_ACK_PUSHED= 4 | |
571 | }; | |
572 | ||
573 | static inline void tcp_schedule_ack(struct tcp_sock *tp) | |
574 | { | |
575 | tp->ack.pending |= TCP_ACK_SCHED; | |
576 | } | |
577 | ||
578 | static inline int tcp_ack_scheduled(struct tcp_sock *tp) | |
579 | { | |
580 | return tp->ack.pending&TCP_ACK_SCHED; | |
581 | } | |
582 | ||
fc6415bc | 583 | static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp, unsigned int pkts) |
1da177e4 | 584 | { |
fc6415bc DM |
585 | if (tp->ack.quick) { |
586 | if (pkts >= tp->ack.quick) { | |
587 | tp->ack.quick = 0; | |
588 | ||
589 | /* Leaving quickack mode we deflate ATO. */ | |
590 | tp->ack.ato = TCP_ATO_MIN; | |
591 | } else | |
592 | tp->ack.quick -= pkts; | |
1da177e4 LT |
593 | } |
594 | } | |
595 | ||
596 | extern void tcp_enter_quickack_mode(struct tcp_sock *tp); | |
597 | ||
598 | static __inline__ void tcp_delack_init(struct tcp_sock *tp) | |
599 | { | |
600 | memset(&tp->ack, 0, sizeof(tp->ack)); | |
601 | } | |
602 | ||
603 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) | |
604 | { | |
605 | rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
606 | } | |
607 | ||
608 | enum tcp_tw_status | |
609 | { | |
610 | TCP_TW_SUCCESS = 0, | |
611 | TCP_TW_RST = 1, | |
612 | TCP_TW_ACK = 2, | |
613 | TCP_TW_SYN = 3 | |
614 | }; | |
615 | ||
616 | ||
617 | extern enum tcp_tw_status tcp_timewait_state_process(struct tcp_tw_bucket *tw, | |
618 | struct sk_buff *skb, | |
619 | struct tcphdr *th, | |
620 | unsigned len); | |
621 | ||
622 | extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, | |
60236fdd ACM |
623 | struct request_sock *req, |
624 | struct request_sock **prev); | |
1da177e4 LT |
625 | extern int tcp_child_process(struct sock *parent, |
626 | struct sock *child, | |
627 | struct sk_buff *skb); | |
628 | extern void tcp_enter_frto(struct sock *sk); | |
629 | extern void tcp_enter_loss(struct sock *sk, int how); | |
630 | extern void tcp_clear_retrans(struct tcp_sock *tp); | |
631 | extern void tcp_update_metrics(struct sock *sk); | |
632 | ||
633 | extern void tcp_close(struct sock *sk, | |
634 | long timeout); | |
635 | extern struct sock * tcp_accept(struct sock *sk, int flags, int *err); | |
636 | extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); | |
637 | ||
638 | extern int tcp_getsockopt(struct sock *sk, int level, | |
639 | int optname, | |
640 | char __user *optval, | |
641 | int __user *optlen); | |
642 | extern int tcp_setsockopt(struct sock *sk, int level, | |
643 | int optname, char __user *optval, | |
644 | int optlen); | |
645 | extern void tcp_set_keepalive(struct sock *sk, int val); | |
646 | extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, | |
647 | struct msghdr *msg, | |
648 | size_t len, int nonblock, | |
649 | int flags, int *addr_len); | |
650 | ||
651 | extern int tcp_listen_start(struct sock *sk); | |
652 | ||
653 | extern void tcp_parse_options(struct sk_buff *skb, | |
654 | struct tcp_options_received *opt_rx, | |
655 | int estab); | |
656 | ||
657 | /* | |
658 | * TCP v4 functions exported for the inet6 API | |
659 | */ | |
660 | ||
1da177e4 LT |
661 | extern void tcp_v4_send_check(struct sock *sk, |
662 | struct tcphdr *th, int len, | |
663 | struct sk_buff *skb); | |
664 | ||
665 | extern int tcp_v4_conn_request(struct sock *sk, | |
666 | struct sk_buff *skb); | |
667 | ||
668 | extern struct sock * tcp_create_openreq_child(struct sock *sk, | |
60236fdd | 669 | struct request_sock *req, |
1da177e4 LT |
670 | struct sk_buff *skb); |
671 | ||
672 | extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, | |
673 | struct sk_buff *skb, | |
60236fdd | 674 | struct request_sock *req, |
1da177e4 LT |
675 | struct dst_entry *dst); |
676 | ||
677 | extern int tcp_v4_do_rcv(struct sock *sk, | |
678 | struct sk_buff *skb); | |
679 | ||
680 | extern int tcp_v4_connect(struct sock *sk, | |
681 | struct sockaddr *uaddr, | |
682 | int addr_len); | |
683 | ||
684 | extern int tcp_connect(struct sock *sk); | |
685 | ||
686 | extern struct sk_buff * tcp_make_synack(struct sock *sk, | |
687 | struct dst_entry *dst, | |
60236fdd | 688 | struct request_sock *req); |
1da177e4 LT |
689 | |
690 | extern int tcp_disconnect(struct sock *sk, int flags); | |
691 | ||
692 | extern void tcp_unhash(struct sock *sk); | |
693 | ||
694 | extern int tcp_v4_hash_connecting(struct sock *sk); | |
695 | ||
696 | ||
697 | /* From syncookies.c */ | |
698 | extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, | |
699 | struct ip_options *opt); | |
700 | extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, | |
701 | __u16 *mss); | |
702 | ||
703 | /* tcp_output.c */ | |
704 | ||
f6302d1d | 705 | extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, |
a2e2a59c | 706 | unsigned int cur_mss, int nonagle); |
f6302d1d | 707 | extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); |
1da177e4 LT |
708 | extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); |
709 | extern void tcp_xmit_retransmit_queue(struct sock *); | |
710 | extern void tcp_simple_retransmit(struct sock *); | |
711 | extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
712 | ||
713 | extern void tcp_send_probe0(struct sock *); | |
714 | extern void tcp_send_partial(struct sock *); | |
715 | extern int tcp_write_wakeup(struct sock *); | |
716 | extern void tcp_send_fin(struct sock *sk); | |
86a76caf VF |
717 | extern void tcp_send_active_reset(struct sock *sk, |
718 | unsigned int __nocast priority); | |
1da177e4 | 719 | extern int tcp_send_synack(struct sock *); |
c1b4a7e6 | 720 | extern void tcp_push_one(struct sock *, unsigned int mss_now); |
1da177e4 LT |
721 | extern void tcp_send_ack(struct sock *sk); |
722 | extern void tcp_send_delayed_ack(struct sock *sk); | |
723 | ||
a762a980 DM |
724 | /* tcp_input.c */ |
725 | extern void tcp_cwnd_application_limited(struct sock *sk); | |
726 | ||
1da177e4 LT |
727 | /* tcp_timer.c */ |
728 | extern void tcp_init_xmit_timers(struct sock *); | |
729 | extern void tcp_clear_xmit_timers(struct sock *); | |
730 | ||
731 | extern void tcp_delete_keepalive_timer(struct sock *); | |
732 | extern void tcp_reset_keepalive_timer(struct sock *, unsigned long); | |
733 | extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); | |
734 | extern unsigned int tcp_current_mss(struct sock *sk, int large); | |
735 | ||
736 | #ifdef TCP_DEBUG | |
737 | extern const char tcp_timer_bug_msg[]; | |
738 | #endif | |
739 | ||
740 | /* tcp_diag.c */ | |
741 | extern void tcp_get_info(struct sock *, struct tcp_info *); | |
742 | ||
743 | /* Read 'sendfile()'-style from a TCP socket */ | |
744 | typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, | |
745 | unsigned int, size_t); | |
746 | extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
747 | sk_read_actor_t recv_actor); | |
748 | ||
749 | static inline void tcp_clear_xmit_timer(struct sock *sk, int what) | |
750 | { | |
751 | struct tcp_sock *tp = tcp_sk(sk); | |
752 | ||
753 | switch (what) { | |
754 | case TCP_TIME_RETRANS: | |
755 | case TCP_TIME_PROBE0: | |
756 | tp->pending = 0; | |
757 | ||
758 | #ifdef TCP_CLEAR_TIMERS | |
759 | sk_stop_timer(sk, &tp->retransmit_timer); | |
760 | #endif | |
761 | break; | |
762 | case TCP_TIME_DACK: | |
763 | tp->ack.blocked = 0; | |
764 | tp->ack.pending = 0; | |
765 | ||
766 | #ifdef TCP_CLEAR_TIMERS | |
767 | sk_stop_timer(sk, &tp->delack_timer); | |
768 | #endif | |
769 | break; | |
770 | default: | |
771 | #ifdef TCP_DEBUG | |
772 | printk(tcp_timer_bug_msg); | |
773 | #endif | |
774 | return; | |
775 | }; | |
776 | ||
777 | } | |
778 | ||
779 | /* | |
780 | * Reset the retransmission timer | |
781 | */ | |
782 | static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when) | |
783 | { | |
784 | struct tcp_sock *tp = tcp_sk(sk); | |
785 | ||
786 | if (when > TCP_RTO_MAX) { | |
787 | #ifdef TCP_DEBUG | |
788 | printk(KERN_DEBUG "reset_xmit_timer sk=%p %d when=0x%lx, caller=%p\n", sk, what, when, current_text_addr()); | |
789 | #endif | |
790 | when = TCP_RTO_MAX; | |
791 | } | |
792 | ||
793 | switch (what) { | |
794 | case TCP_TIME_RETRANS: | |
795 | case TCP_TIME_PROBE0: | |
796 | tp->pending = what; | |
797 | tp->timeout = jiffies+when; | |
798 | sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout); | |
799 | break; | |
800 | ||
801 | case TCP_TIME_DACK: | |
802 | tp->ack.pending |= TCP_ACK_TIMER; | |
803 | tp->ack.timeout = jiffies+when; | |
804 | sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout); | |
805 | break; | |
806 | ||
807 | default: | |
808 | #ifdef TCP_DEBUG | |
809 | printk(tcp_timer_bug_msg); | |
810 | #endif | |
811 | return; | |
812 | }; | |
813 | } | |
814 | ||
815 | /* Initialize RCV_MSS value. | |
816 | * RCV_MSS is an our guess about MSS used by the peer. | |
817 | * We haven't any direct information about the MSS. | |
818 | * It's better to underestimate the RCV_MSS rather than overestimate. | |
819 | * Overestimations make us ACKing less frequently than needed. | |
820 | * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). | |
821 | */ | |
822 | ||
823 | static inline void tcp_initialize_rcv_mss(struct sock *sk) | |
824 | { | |
825 | struct tcp_sock *tp = tcp_sk(sk); | |
c1b4a7e6 | 826 | unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); |
1da177e4 LT |
827 | |
828 | hint = min(hint, tp->rcv_wnd/2); | |
829 | hint = min(hint, TCP_MIN_RCVMSS); | |
830 | hint = max(hint, TCP_MIN_MSS); | |
831 | ||
832 | tp->ack.rcv_mss = hint; | |
833 | } | |
834 | ||
835 | static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) | |
836 | { | |
837 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
838 | ntohl(TCP_FLAG_ACK) | | |
839 | snd_wnd); | |
840 | } | |
841 | ||
842 | static __inline__ void tcp_fast_path_on(struct tcp_sock *tp) | |
843 | { | |
844 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
845 | } | |
846 | ||
847 | static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) | |
848 | { | |
b03efcfb | 849 | if (skb_queue_empty(&tp->out_of_order_queue) && |
1da177e4 LT |
850 | tp->rcv_wnd && |
851 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
852 | !tp->urg_data) | |
853 | tcp_fast_path_on(tp); | |
854 | } | |
855 | ||
856 | /* Compute the actual receive window we are currently advertising. | |
857 | * Rcv_nxt can be after the window if our peer push more data | |
858 | * than the offered window. | |
859 | */ | |
860 | static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) | |
861 | { | |
862 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
863 | ||
864 | if (win < 0) | |
865 | win = 0; | |
866 | return (u32) win; | |
867 | } | |
868 | ||
869 | /* Choose a new window, without checks for shrinking, and without | |
870 | * scaling applied to the result. The caller does these things | |
871 | * if necessary. This is a "raw" window selection. | |
872 | */ | |
873 | extern u32 __tcp_select_window(struct sock *sk); | |
874 | ||
875 | /* TCP timestamps are only 32-bits, this causes a slight | |
876 | * complication on 64-bit systems since we store a snapshot | |
877 | * of jiffies in the buffer control blocks below. We decidely | |
878 | * only use of the low 32-bits of jiffies and hide the ugly | |
879 | * casts with the following macro. | |
880 | */ | |
881 | #define tcp_time_stamp ((__u32)(jiffies)) | |
882 | ||
883 | /* This is what the send packet queueing engine uses to pass | |
884 | * TCP per-packet control information to the transmission | |
885 | * code. We also store the host-order sequence numbers in | |
886 | * here too. This is 36 bytes on 32-bit architectures, | |
887 | * 40 bytes on 64-bit machines, if this grows please adjust | |
888 | * skbuff.h:skbuff->cb[xxx] size appropriately. | |
889 | */ | |
890 | struct tcp_skb_cb { | |
891 | union { | |
892 | struct inet_skb_parm h4; | |
893 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
894 | struct inet6_skb_parm h6; | |
895 | #endif | |
896 | } header; /* For incoming frames */ | |
897 | __u32 seq; /* Starting sequence number */ | |
898 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
899 | __u32 when; /* used to compute rtt's */ | |
900 | __u8 flags; /* TCP header flags. */ | |
901 | ||
902 | /* NOTE: These must match up to the flags byte in a | |
903 | * real TCP header. | |
904 | */ | |
905 | #define TCPCB_FLAG_FIN 0x01 | |
906 | #define TCPCB_FLAG_SYN 0x02 | |
907 | #define TCPCB_FLAG_RST 0x04 | |
908 | #define TCPCB_FLAG_PSH 0x08 | |
909 | #define TCPCB_FLAG_ACK 0x10 | |
910 | #define TCPCB_FLAG_URG 0x20 | |
911 | #define TCPCB_FLAG_ECE 0x40 | |
912 | #define TCPCB_FLAG_CWR 0x80 | |
913 | ||
914 | __u8 sacked; /* State flags for SACK/FACK. */ | |
915 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
916 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
917 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
918 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
919 | ||
920 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
921 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) | |
922 | ||
923 | #define TCPCB_URG 0x20 /* Urgent pointer advenced here */ | |
924 | ||
925 | #define TCPCB_AT_TAIL (TCPCB_URG) | |
926 | ||
927 | __u16 urg_ptr; /* Valid w/URG flags is set. */ | |
928 | __u32 ack_seq; /* Sequence number ACK'd */ | |
929 | }; | |
930 | ||
931 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
932 | ||
933 | #include <net/tcp_ecn.h> | |
934 | ||
935 | /* Due to TSO, an SKB can be composed of multiple actual | |
936 | * packets. To keep these tracked properly, we use this. | |
937 | */ | |
938 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
939 | { | |
940 | return skb_shinfo(skb)->tso_segs; | |
941 | } | |
942 | ||
943 | /* This is valid iff tcp_skb_pcount() > 1. */ | |
944 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
945 | { | |
946 | return skb_shinfo(skb)->tso_size; | |
947 | } | |
948 | ||
949 | static inline void tcp_dec_pcount_approx(__u32 *count, | |
950 | const struct sk_buff *skb) | |
951 | { | |
952 | if (*count) { | |
953 | *count -= tcp_skb_pcount(skb); | |
954 | if ((int)*count < 0) | |
955 | *count = 0; | |
956 | } | |
957 | } | |
958 | ||
959 | static inline void tcp_packets_out_inc(struct sock *sk, | |
960 | struct tcp_sock *tp, | |
961 | const struct sk_buff *skb) | |
962 | { | |
963 | int orig = tp->packets_out; | |
964 | ||
965 | tp->packets_out += tcp_skb_pcount(skb); | |
966 | if (!orig) | |
967 | tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto); | |
968 | } | |
969 | ||
970 | static inline void tcp_packets_out_dec(struct tcp_sock *tp, | |
971 | const struct sk_buff *skb) | |
972 | { | |
973 | tp->packets_out -= tcp_skb_pcount(skb); | |
974 | } | |
975 | ||
317a76f9 SH |
976 | /* Events passed to congestion control interface */ |
977 | enum tcp_ca_event { | |
978 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
979 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
980 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
981 | CA_EVENT_FRTO, /* fast recovery timeout */ | |
982 | CA_EVENT_LOSS, /* loss timeout */ | |
983 | CA_EVENT_FAST_ACK, /* in sequence ack */ | |
984 | CA_EVENT_SLOW_ACK, /* other ack */ | |
985 | }; | |
986 | ||
987 | /* | |
988 | * Interface for adding new TCP congestion control handlers | |
989 | */ | |
990 | #define TCP_CA_NAME_MAX 16 | |
991 | struct tcp_congestion_ops { | |
992 | struct list_head list; | |
993 | ||
994 | /* initialize private data (optional) */ | |
995 | void (*init)(struct tcp_sock *tp); | |
996 | /* cleanup private data (optional) */ | |
997 | void (*release)(struct tcp_sock *tp); | |
998 | ||
999 | /* return slow start threshold (required) */ | |
1000 | u32 (*ssthresh)(struct tcp_sock *tp); | |
1001 | /* lower bound for congestion window (optional) */ | |
1002 | u32 (*min_cwnd)(struct tcp_sock *tp); | |
1003 | /* do new cwnd calculation (required) */ | |
1004 | void (*cong_avoid)(struct tcp_sock *tp, u32 ack, | |
1005 | u32 rtt, u32 in_flight, int good_ack); | |
1006 | /* round trip time sample per acked packet (optional) */ | |
1007 | void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt); | |
1008 | /* call before changing ca_state (optional) */ | |
1009 | void (*set_state)(struct tcp_sock *tp, u8 new_state); | |
1010 | /* call when cwnd event occurs (optional) */ | |
1011 | void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev); | |
1012 | /* new value of cwnd after loss (optional) */ | |
1013 | u32 (*undo_cwnd)(struct tcp_sock *tp); | |
1014 | /* hook for packet ack accounting (optional) */ | |
1015 | void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked); | |
1016 | /* get info for tcp_diag (optional) */ | |
1017 | void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb); | |
1018 | ||
1019 | char name[TCP_CA_NAME_MAX]; | |
1020 | struct module *owner; | |
1021 | }; | |
1022 | ||
1023 | extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
1024 | extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
1025 | ||
1026 | extern void tcp_init_congestion_control(struct tcp_sock *tp); | |
1027 | extern void tcp_cleanup_congestion_control(struct tcp_sock *tp); | |
1028 | extern int tcp_set_default_congestion_control(const char *name); | |
1029 | extern void tcp_get_default_congestion_control(char *name); | |
5f8ef48d | 1030 | extern int tcp_set_congestion_control(struct tcp_sock *tp, const char *name); |
317a76f9 | 1031 | |
5f8ef48d | 1032 | extern struct tcp_congestion_ops tcp_init_congestion_ops; |
317a76f9 SH |
1033 | extern u32 tcp_reno_ssthresh(struct tcp_sock *tp); |
1034 | extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack, | |
1035 | u32 rtt, u32 in_flight, int flag); | |
1036 | extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp); | |
a8acfbac | 1037 | extern struct tcp_congestion_ops tcp_reno; |
317a76f9 SH |
1038 | |
1039 | static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state) | |
1040 | { | |
1041 | if (tp->ca_ops->set_state) | |
1042 | tp->ca_ops->set_state(tp, ca_state); | |
1043 | tp->ca_state = ca_state; | |
1044 | } | |
1045 | ||
1046 | static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event) | |
1047 | { | |
1048 | if (tp->ca_ops->cwnd_event) | |
1049 | tp->ca_ops->cwnd_event(tp, event); | |
1050 | } | |
1051 | ||
1da177e4 LT |
1052 | /* This determines how many packets are "in the network" to the best |
1053 | * of our knowledge. In many cases it is conservative, but where | |
1054 | * detailed information is available from the receiver (via SACK | |
1055 | * blocks etc.) we can make more aggressive calculations. | |
1056 | * | |
1057 | * Use this for decisions involving congestion control, use just | |
1058 | * tp->packets_out to determine if the send queue is empty or not. | |
1059 | * | |
1060 | * Read this equation as: | |
1061 | * | |
1062 | * "Packets sent once on transmission queue" MINUS | |
1063 | * "Packets left network, but not honestly ACKed yet" PLUS | |
1064 | * "Packets fast retransmitted" | |
1065 | */ | |
1066 | static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) | |
1067 | { | |
1068 | return (tp->packets_out - tp->left_out + tp->retrans_out); | |
1069 | } | |
1070 | ||
1da177e4 LT |
1071 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. |
1072 | * The exception is rate halving phase, when cwnd is decreasing towards | |
1073 | * ssthresh. | |
1074 | */ | |
1075 | static inline __u32 tcp_current_ssthresh(struct tcp_sock *tp) | |
1076 | { | |
1077 | if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery)) | |
1078 | return tp->snd_ssthresh; | |
1079 | else | |
1080 | return max(tp->snd_ssthresh, | |
1081 | ((tp->snd_cwnd >> 1) + | |
1082 | (tp->snd_cwnd >> 2))); | |
1083 | } | |
1084 | ||
1085 | static inline void tcp_sync_left_out(struct tcp_sock *tp) | |
1086 | { | |
1087 | if (tp->rx_opt.sack_ok && | |
1088 | (tp->sacked_out >= tp->packets_out - tp->lost_out)) | |
1089 | tp->sacked_out = tp->packets_out - tp->lost_out; | |
1090 | tp->left_out = tp->sacked_out + tp->lost_out; | |
1091 | } | |
1092 | ||
d1b04c08 | 1093 | /* Set slow start threshold and cwnd not falling to slow start */ |
1da177e4 LT |
1094 | static inline void __tcp_enter_cwr(struct tcp_sock *tp) |
1095 | { | |
1096 | tp->undo_marker = 0; | |
317a76f9 | 1097 | tp->snd_ssthresh = tp->ca_ops->ssthresh(tp); |
1da177e4 LT |
1098 | tp->snd_cwnd = min(tp->snd_cwnd, |
1099 | tcp_packets_in_flight(tp) + 1U); | |
1100 | tp->snd_cwnd_cnt = 0; | |
1101 | tp->high_seq = tp->snd_nxt; | |
1102 | tp->snd_cwnd_stamp = tcp_time_stamp; | |
1103 | TCP_ECN_queue_cwr(tp); | |
1104 | } | |
1105 | ||
1106 | static inline void tcp_enter_cwr(struct tcp_sock *tp) | |
1107 | { | |
1108 | tp->prior_ssthresh = 0; | |
1109 | if (tp->ca_state < TCP_CA_CWR) { | |
1110 | __tcp_enter_cwr(tp); | |
1111 | tcp_set_ca_state(tp, TCP_CA_CWR); | |
1112 | } | |
1113 | } | |
1114 | ||
1115 | extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); | |
1116 | ||
1117 | /* Slow start with delack produces 3 packets of burst, so that | |
1118 | * it is safe "de facto". | |
1119 | */ | |
1120 | static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) | |
1121 | { | |
1122 | return 3; | |
1123 | } | |
1124 | ||
1da177e4 LT |
1125 | static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, |
1126 | const struct sk_buff *skb) | |
1127 | { | |
1128 | if (skb->len < mss) | |
1129 | tp->snd_sml = TCP_SKB_CB(skb)->end_seq; | |
1130 | } | |
1131 | ||
1da177e4 LT |
1132 | static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) |
1133 | { | |
1134 | if (!tp->packets_out && !tp->pending) | |
1135 | tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto); | |
1136 | } | |
1137 | ||
1da177e4 LT |
1138 | static __inline__ void tcp_push_pending_frames(struct sock *sk, |
1139 | struct tcp_sock *tp) | |
1140 | { | |
1141 | __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); | |
1142 | } | |
1143 | ||
1da177e4 LT |
1144 | static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) |
1145 | { | |
1146 | tp->snd_wl1 = seq; | |
1147 | } | |
1148 | ||
1149 | static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) | |
1150 | { | |
1151 | tp->snd_wl1 = seq; | |
1152 | } | |
1153 | ||
1154 | extern void tcp_destroy_sock(struct sock *sk); | |
1155 | ||
1156 | ||
1157 | /* | |
1158 | * Calculate(/check) TCP checksum | |
1159 | */ | |
1160 | static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, | |
1161 | unsigned long saddr, unsigned long daddr, | |
1162 | unsigned long base) | |
1163 | { | |
1164 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
1165 | } | |
1166 | ||
1167 | static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) | |
1168 | { | |
1169 | return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); | |
1170 | } | |
1171 | ||
1172 | static __inline__ int tcp_checksum_complete(struct sk_buff *skb) | |
1173 | { | |
1174 | return skb->ip_summed != CHECKSUM_UNNECESSARY && | |
1175 | __tcp_checksum_complete(skb); | |
1176 | } | |
1177 | ||
1178 | /* Prequeue for VJ style copy to user, combined with checksumming. */ | |
1179 | ||
1180 | static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) | |
1181 | { | |
1182 | tp->ucopy.task = NULL; | |
1183 | tp->ucopy.len = 0; | |
1184 | tp->ucopy.memory = 0; | |
1185 | skb_queue_head_init(&tp->ucopy.prequeue); | |
1186 | } | |
1187 | ||
1188 | /* Packet is added to VJ-style prequeue for processing in process | |
1189 | * context, if a reader task is waiting. Apparently, this exciting | |
1190 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) | |
1191 | * failed somewhere. Latency? Burstiness? Well, at least now we will | |
1192 | * see, why it failed. 8)8) --ANK | |
1193 | * | |
1194 | * NOTE: is this not too big to inline? | |
1195 | */ | |
1196 | static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) | |
1197 | { | |
1198 | struct tcp_sock *tp = tcp_sk(sk); | |
1199 | ||
1200 | if (!sysctl_tcp_low_latency && tp->ucopy.task) { | |
1201 | __skb_queue_tail(&tp->ucopy.prequeue, skb); | |
1202 | tp->ucopy.memory += skb->truesize; | |
1203 | if (tp->ucopy.memory > sk->sk_rcvbuf) { | |
1204 | struct sk_buff *skb1; | |
1205 | ||
1206 | BUG_ON(sock_owned_by_user(sk)); | |
1207 | ||
1208 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { | |
1209 | sk->sk_backlog_rcv(sk, skb1); | |
1210 | NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); | |
1211 | } | |
1212 | ||
1213 | tp->ucopy.memory = 0; | |
1214 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { | |
1215 | wake_up_interruptible(sk->sk_sleep); | |
1216 | if (!tcp_ack_scheduled(tp)) | |
1217 | tcp_reset_xmit_timer(sk, TCP_TIME_DACK, (3*TCP_RTO_MIN)/4); | |
1218 | } | |
1219 | return 1; | |
1220 | } | |
1221 | return 0; | |
1222 | } | |
1223 | ||
1224 | ||
1225 | #undef STATE_TRACE | |
1226 | ||
1227 | #ifdef STATE_TRACE | |
1228 | static const char *statename[]={ | |
1229 | "Unused","Established","Syn Sent","Syn Recv", | |
1230 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
1231 | "Close Wait","Last ACK","Listen","Closing" | |
1232 | }; | |
1233 | #endif | |
1234 | ||
1235 | static __inline__ void tcp_set_state(struct sock *sk, int state) | |
1236 | { | |
1237 | int oldstate = sk->sk_state; | |
1238 | ||
1239 | switch (state) { | |
1240 | case TCP_ESTABLISHED: | |
1241 | if (oldstate != TCP_ESTABLISHED) | |
1242 | TCP_INC_STATS(TCP_MIB_CURRESTAB); | |
1243 | break; | |
1244 | ||
1245 | case TCP_CLOSE: | |
1246 | if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) | |
1247 | TCP_INC_STATS(TCP_MIB_ESTABRESETS); | |
1248 | ||
1249 | sk->sk_prot->unhash(sk); | |
a55ebcc4 | 1250 | if (inet_sk(sk)->bind_hash && |
1da177e4 | 1251 | !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) |
2d8c4ce5 | 1252 | inet_put_port(&tcp_hashinfo, sk); |
1da177e4 LT |
1253 | /* fall through */ |
1254 | default: | |
1255 | if (oldstate==TCP_ESTABLISHED) | |
1256 | TCP_DEC_STATS(TCP_MIB_CURRESTAB); | |
1257 | } | |
1258 | ||
1259 | /* Change state AFTER socket is unhashed to avoid closed | |
1260 | * socket sitting in hash tables. | |
1261 | */ | |
1262 | sk->sk_state = state; | |
1263 | ||
1264 | #ifdef STATE_TRACE | |
1265 | SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); | |
1266 | #endif | |
1267 | } | |
1268 | ||
1269 | static __inline__ void tcp_done(struct sock *sk) | |
1270 | { | |
1271 | tcp_set_state(sk, TCP_CLOSE); | |
1272 | tcp_clear_xmit_timers(sk); | |
1273 | ||
1274 | sk->sk_shutdown = SHUTDOWN_MASK; | |
1275 | ||
1276 | if (!sock_flag(sk, SOCK_DEAD)) | |
1277 | sk->sk_state_change(sk); | |
1278 | else | |
1279 | tcp_destroy_sock(sk); | |
1280 | } | |
1281 | ||
1282 | static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) | |
1283 | { | |
1284 | rx_opt->dsack = 0; | |
1285 | rx_opt->eff_sacks = 0; | |
1286 | rx_opt->num_sacks = 0; | |
1287 | } | |
1288 | ||
1289 | static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) | |
1290 | { | |
1291 | if (tp->rx_opt.tstamp_ok) { | |
1292 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | | |
1293 | (TCPOPT_NOP << 16) | | |
1294 | (TCPOPT_TIMESTAMP << 8) | | |
1295 | TCPOLEN_TIMESTAMP); | |
1296 | *ptr++ = htonl(tstamp); | |
1297 | *ptr++ = htonl(tp->rx_opt.ts_recent); | |
1298 | } | |
1299 | if (tp->rx_opt.eff_sacks) { | |
1300 | struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; | |
1301 | int this_sack; | |
1302 | ||
1303 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | | |
1304 | (TCPOPT_NOP << 16) | | |
1305 | (TCPOPT_SACK << 8) | | |
1306 | (TCPOLEN_SACK_BASE + | |
1307 | (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK))); | |
1308 | for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { | |
1309 | *ptr++ = htonl(sp[this_sack].start_seq); | |
1310 | *ptr++ = htonl(sp[this_sack].end_seq); | |
1311 | } | |
1312 | if (tp->rx_opt.dsack) { | |
1313 | tp->rx_opt.dsack = 0; | |
1314 | tp->rx_opt.eff_sacks--; | |
1315 | } | |
1316 | } | |
1317 | } | |
1318 | ||
1319 | /* Construct a tcp options header for a SYN or SYN_ACK packet. | |
1320 | * If this is every changed make sure to change the definition of | |
1321 | * MAX_SYN_SIZE to match the new maximum number of options that you | |
1322 | * can generate. | |
1323 | */ | |
1324 | static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, | |
1325 | int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) | |
1326 | { | |
1327 | /* We always get an MSS option. | |
1328 | * The option bytes which will be seen in normal data | |
1329 | * packets should timestamps be used, must be in the MSS | |
1330 | * advertised. But we subtract them from tp->mss_cache so | |
1331 | * that calculations in tcp_sendmsg are simpler etc. | |
1332 | * So account for this fact here if necessary. If we | |
1333 | * don't do this correctly, as a receiver we won't | |
1334 | * recognize data packets as being full sized when we | |
1335 | * should, and thus we won't abide by the delayed ACK | |
1336 | * rules correctly. | |
1337 | * SACKs don't matter, we never delay an ACK when we | |
1338 | * have any of those going out. | |
1339 | */ | |
1340 | *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); | |
1341 | if (ts) { | |
1342 | if(sack) | |
1343 | *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | | |
1344 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1345 | else | |
1346 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1347 | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); | |
1348 | *ptr++ = htonl(tstamp); /* TSVAL */ | |
1349 | *ptr++ = htonl(ts_recent); /* TSECR */ | |
1350 | } else if(sack) | |
1351 | *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1352 | (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); | |
1353 | if (offer_wscale) | |
1354 | *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); | |
1355 | } | |
1356 | ||
1357 | /* Determine a window scaling and initial window to offer. */ | |
1358 | extern void tcp_select_initial_window(int __space, __u32 mss, | |
1359 | __u32 *rcv_wnd, __u32 *window_clamp, | |
1360 | int wscale_ok, __u8 *rcv_wscale); | |
1361 | ||
1362 | static inline int tcp_win_from_space(int space) | |
1363 | { | |
1364 | return sysctl_tcp_adv_win_scale<=0 ? | |
1365 | (space>>(-sysctl_tcp_adv_win_scale)) : | |
1366 | space - (space>>sysctl_tcp_adv_win_scale); | |
1367 | } | |
1368 | ||
1369 | /* Note: caller must be prepared to deal with negative returns */ | |
1370 | static inline int tcp_space(const struct sock *sk) | |
1371 | { | |
1372 | return tcp_win_from_space(sk->sk_rcvbuf - | |
1373 | atomic_read(&sk->sk_rmem_alloc)); | |
1374 | } | |
1375 | ||
1376 | static inline int tcp_full_space(const struct sock *sk) | |
1377 | { | |
1378 | return tcp_win_from_space(sk->sk_rcvbuf); | |
1379 | } | |
1380 | ||
60236fdd | 1381 | static inline void tcp_acceptq_queue(struct sock *sk, struct request_sock *req, |
1da177e4 LT |
1382 | struct sock *child) |
1383 | { | |
0e87506f | 1384 | reqsk_queue_add(&tcp_sk(sk)->accept_queue, req, sk, child); |
1da177e4 LT |
1385 | } |
1386 | ||
1da177e4 | 1387 | static inline void |
60236fdd | 1388 | tcp_synq_removed(struct sock *sk, struct request_sock *req) |
1da177e4 | 1389 | { |
0e87506f | 1390 | if (reqsk_queue_removed(&tcp_sk(sk)->accept_queue, req) == 0) |
1da177e4 | 1391 | tcp_delete_keepalive_timer(sk); |
1da177e4 LT |
1392 | } |
1393 | ||
1394 | static inline void tcp_synq_added(struct sock *sk) | |
1395 | { | |
0e87506f | 1396 | if (reqsk_queue_added(&tcp_sk(sk)->accept_queue) == 0) |
1da177e4 | 1397 | tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT); |
1da177e4 LT |
1398 | } |
1399 | ||
1400 | static inline int tcp_synq_len(struct sock *sk) | |
1401 | { | |
0e87506f | 1402 | return reqsk_queue_len(&tcp_sk(sk)->accept_queue); |
1da177e4 LT |
1403 | } |
1404 | ||
1405 | static inline int tcp_synq_young(struct sock *sk) | |
1406 | { | |
0e87506f | 1407 | return reqsk_queue_len_young(&tcp_sk(sk)->accept_queue); |
1da177e4 LT |
1408 | } |
1409 | ||
1410 | static inline int tcp_synq_is_full(struct sock *sk) | |
1411 | { | |
0e87506f | 1412 | return reqsk_queue_is_full(&tcp_sk(sk)->accept_queue); |
1da177e4 LT |
1413 | } |
1414 | ||
60236fdd | 1415 | static inline void tcp_synq_unlink(struct tcp_sock *tp, struct request_sock *req, |
0e87506f | 1416 | struct request_sock **prev) |
1da177e4 | 1417 | { |
0e87506f | 1418 | reqsk_queue_unlink(&tp->accept_queue, req, prev); |
1da177e4 LT |
1419 | } |
1420 | ||
60236fdd ACM |
1421 | static inline void tcp_synq_drop(struct sock *sk, struct request_sock *req, |
1422 | struct request_sock **prev) | |
1da177e4 LT |
1423 | { |
1424 | tcp_synq_unlink(tcp_sk(sk), req, prev); | |
1425 | tcp_synq_removed(sk, req); | |
60236fdd | 1426 | reqsk_free(req); |
1da177e4 LT |
1427 | } |
1428 | ||
60236fdd | 1429 | static __inline__ void tcp_openreq_init(struct request_sock *req, |
1da177e4 LT |
1430 | struct tcp_options_received *rx_opt, |
1431 | struct sk_buff *skb) | |
1432 | { | |
2e6599cb ACM |
1433 | struct inet_request_sock *ireq = inet_rsk(req); |
1434 | ||
1da177e4 | 1435 | req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
2e6599cb | 1436 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
1da177e4 LT |
1437 | req->mss = rx_opt->mss_clamp; |
1438 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; | |
2e6599cb ACM |
1439 | ireq->tstamp_ok = rx_opt->tstamp_ok; |
1440 | ireq->sack_ok = rx_opt->sack_ok; | |
1441 | ireq->snd_wscale = rx_opt->snd_wscale; | |
1442 | ireq->wscale_ok = rx_opt->wscale_ok; | |
1443 | ireq->acked = 0; | |
1444 | ireq->ecn_ok = 0; | |
1445 | ireq->rmt_port = skb->h.th->source; | |
1da177e4 LT |
1446 | } |
1447 | ||
1448 | extern void tcp_enter_memory_pressure(void); | |
1449 | ||
1da177e4 LT |
1450 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) |
1451 | { | |
1452 | return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; | |
1453 | } | |
1454 | ||
1455 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1456 | { | |
1457 | return tp->keepalive_time ? : sysctl_tcp_keepalive_time; | |
1458 | } | |
1459 | ||
1460 | static inline int tcp_fin_time(const struct tcp_sock *tp) | |
1461 | { | |
1462 | int fin_timeout = tp->linger2 ? : sysctl_tcp_fin_timeout; | |
1463 | ||
1464 | if (fin_timeout < (tp->rto<<2) - (tp->rto>>1)) | |
1465 | fin_timeout = (tp->rto<<2) - (tp->rto>>1); | |
1466 | ||
1467 | return fin_timeout; | |
1468 | } | |
1469 | ||
1470 | static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) | |
1471 | { | |
1472 | if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) | |
1473 | return 0; | |
1474 | if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) | |
1475 | return 0; | |
1476 | ||
1477 | /* RST segments are not recommended to carry timestamp, | |
1478 | and, if they do, it is recommended to ignore PAWS because | |
1479 | "their cleanup function should take precedence over timestamps." | |
1480 | Certainly, it is mistake. It is necessary to understand the reasons | |
1481 | of this constraint to relax it: if peer reboots, clock may go | |
1482 | out-of-sync and half-open connections will not be reset. | |
1483 | Actually, the problem would be not existing if all | |
1484 | the implementations followed draft about maintaining clock | |
1485 | via reboots. Linux-2.2 DOES NOT! | |
1486 | ||
1487 | However, we can relax time bounds for RST segments to MSL. | |
1488 | */ | |
1489 | if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) | |
1490 | return 0; | |
1491 | return 1; | |
1492 | } | |
1493 | ||
1da177e4 LT |
1494 | #define TCP_CHECK_TIMER(sk) do { } while (0) |
1495 | ||
1496 | static inline int tcp_use_frto(const struct sock *sk) | |
1497 | { | |
1498 | const struct tcp_sock *tp = tcp_sk(sk); | |
1499 | ||
1500 | /* F-RTO must be activated in sysctl and there must be some | |
1501 | * unsent new data, and the advertised window should allow | |
1502 | * sending it. | |
1503 | */ | |
1504 | return (sysctl_tcp_frto && sk->sk_send_head && | |
1505 | !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, | |
1506 | tp->snd_una + tp->snd_wnd)); | |
1507 | } | |
1508 | ||
1509 | static inline void tcp_mib_init(void) | |
1510 | { | |
1511 | /* See RFC 2012 */ | |
1512 | TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); | |
1513 | TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1514 | TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1515 | TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); | |
1516 | } | |
1517 | ||
1518 | /* /proc */ | |
1519 | enum tcp_seq_states { | |
1520 | TCP_SEQ_STATE_LISTENING, | |
1521 | TCP_SEQ_STATE_OPENREQ, | |
1522 | TCP_SEQ_STATE_ESTABLISHED, | |
1523 | TCP_SEQ_STATE_TIME_WAIT, | |
1524 | }; | |
1525 | ||
1526 | struct tcp_seq_afinfo { | |
1527 | struct module *owner; | |
1528 | char *name; | |
1529 | sa_family_t family; | |
1530 | int (*seq_show) (struct seq_file *m, void *v); | |
1531 | struct file_operations *seq_fops; | |
1532 | }; | |
1533 | ||
1534 | struct tcp_iter_state { | |
1535 | sa_family_t family; | |
1536 | enum tcp_seq_states state; | |
1537 | struct sock *syn_wait_sk; | |
1538 | int bucket, sbucket, num, uid; | |
1539 | struct seq_operations seq_ops; | |
1540 | }; | |
1541 | ||
1542 | extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); | |
1543 | extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); | |
1544 | ||
1da177e4 | 1545 | #endif /* _TCP_H */ |