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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 | * Implementation of the Transmission Control Protocol(TCP). | |
7 | * | |
8 | * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $ | |
9 | * | |
10 | * IPv4 specific functions | |
11 | * | |
12 | * | |
13 | * code split from: | |
14 | * linux/ipv4/tcp.c | |
15 | * linux/ipv4/tcp_input.c | |
16 | * linux/ipv4/tcp_output.c | |
17 | * | |
18 | * See tcp.c for author information | |
19 | * | |
20 | * This program is free software; you can redistribute it and/or | |
21 | * modify it under the terms of the GNU General Public License | |
22 | * as published by the Free Software Foundation; either version | |
23 | * 2 of the License, or (at your option) any later version. | |
24 | */ | |
25 | ||
26 | /* | |
27 | * Changes: | |
28 | * David S. Miller : New socket lookup architecture. | |
29 | * This code is dedicated to John Dyson. | |
30 | * David S. Miller : Change semantics of established hash, | |
31 | * half is devoted to TIME_WAIT sockets | |
32 | * and the rest go in the other half. | |
33 | * Andi Kleen : Add support for syncookies and fixed | |
34 | * some bugs: ip options weren't passed to | |
35 | * the TCP layer, missed a check for an | |
36 | * ACK bit. | |
37 | * Andi Kleen : Implemented fast path mtu discovery. | |
38 | * Fixed many serious bugs in the | |
60236fdd | 39 | * request_sock handling and moved |
1da177e4 LT |
40 | * most of it into the af independent code. |
41 | * Added tail drop and some other bugfixes. | |
42 | * Added new listen sematics. | |
43 | * Mike McLagan : Routing by source | |
44 | * Juan Jose Ciarlante: ip_dynaddr bits | |
45 | * Andi Kleen: various fixes. | |
46 | * Vitaly E. Lavrov : Transparent proxy revived after year | |
47 | * coma. | |
48 | * Andi Kleen : Fix new listen. | |
49 | * Andi Kleen : Fix accept error reporting. | |
50 | * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which | |
51 | * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind | |
52 | * a single port at the same time. | |
53 | */ | |
54 | ||
55 | #include <linux/config.h> | |
56 | ||
57 | #include <linux/types.h> | |
58 | #include <linux/fcntl.h> | |
59 | #include <linux/module.h> | |
60 | #include <linux/random.h> | |
61 | #include <linux/cache.h> | |
62 | #include <linux/jhash.h> | |
63 | #include <linux/init.h> | |
64 | #include <linux/times.h> | |
65 | ||
66 | #include <net/icmp.h> | |
304a1618 | 67 | #include <net/inet_hashtables.h> |
1da177e4 LT |
68 | #include <net/tcp.h> |
69 | #include <net/ipv6.h> | |
70 | #include <net/inet_common.h> | |
71 | #include <net/xfrm.h> | |
72 | ||
73 | #include <linux/inet.h> | |
74 | #include <linux/ipv6.h> | |
75 | #include <linux/stddef.h> | |
76 | #include <linux/proc_fs.h> | |
77 | #include <linux/seq_file.h> | |
78 | ||
79 | extern int sysctl_ip_dynaddr; | |
80 | int sysctl_tcp_tw_reuse; | |
81 | int sysctl_tcp_low_latency; | |
82 | ||
83 | /* Check TCP sequence numbers in ICMP packets. */ | |
84 | #define ICMP_MIN_LENGTH 8 | |
85 | ||
86 | /* Socket used for sending RSTs */ | |
87 | static struct socket *tcp_socket; | |
88 | ||
89 | void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len, | |
90 | struct sk_buff *skb); | |
91 | ||
0f7ff927 ACM |
92 | struct inet_hashinfo __cacheline_aligned tcp_hashinfo = { |
93 | .lhash_lock = RW_LOCK_UNLOCKED, | |
94 | .lhash_users = ATOMIC_INIT(0), | |
95 | .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait), | |
96 | .portalloc_lock = SPIN_LOCK_UNLOCKED, | |
1da177e4 LT |
97 | }; |
98 | ||
99 | /* | |
100 | * This array holds the first and last local port number. | |
101 | * For high-usage systems, use sysctl to change this to | |
102 | * 32768-61000 | |
103 | */ | |
104 | int sysctl_local_port_range[2] = { 1024, 4999 }; | |
105 | int tcp_port_rover = 1024 - 1; | |
106 | ||
1da177e4 LT |
107 | /* Caller must disable local BH processing. */ |
108 | static __inline__ void __tcp_inherit_port(struct sock *sk, struct sock *child) | |
109 | { | |
0f7ff927 ACM |
110 | struct inet_bind_hashbucket *head = |
111 | &tcp_bhash[inet_bhashfn(inet_sk(child)->num, | |
112 | tcp_bhash_size)]; | |
113 | struct inet_bind_bucket *tb; | |
1da177e4 LT |
114 | |
115 | spin_lock(&head->lock); | |
a55ebcc4 | 116 | tb = inet_sk(sk)->bind_hash; |
1da177e4 | 117 | sk_add_bind_node(child, &tb->owners); |
a55ebcc4 | 118 | inet_sk(child)->bind_hash = tb; |
1da177e4 LT |
119 | spin_unlock(&head->lock); |
120 | } | |
121 | ||
122 | inline void tcp_inherit_port(struct sock *sk, struct sock *child) | |
123 | { | |
124 | local_bh_disable(); | |
125 | __tcp_inherit_port(sk, child); | |
126 | local_bh_enable(); | |
127 | } | |
128 | ||
0f7ff927 ACM |
129 | void tcp_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, |
130 | const unsigned short snum) | |
1da177e4 | 131 | { |
a55ebcc4 ACM |
132 | struct inet_sock *inet = inet_sk(sk); |
133 | inet->num = snum; | |
1da177e4 | 134 | sk_add_bind_node(sk, &tb->owners); |
a55ebcc4 | 135 | inet->bind_hash = tb; |
1da177e4 LT |
136 | } |
137 | ||
0f7ff927 | 138 | static inline int tcp_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb) |
1da177e4 LT |
139 | { |
140 | const u32 sk_rcv_saddr = tcp_v4_rcv_saddr(sk); | |
141 | struct sock *sk2; | |
142 | struct hlist_node *node; | |
143 | int reuse = sk->sk_reuse; | |
144 | ||
145 | sk_for_each_bound(sk2, node, &tb->owners) { | |
146 | if (sk != sk2 && | |
147 | !tcp_v6_ipv6only(sk2) && | |
148 | (!sk->sk_bound_dev_if || | |
149 | !sk2->sk_bound_dev_if || | |
150 | sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { | |
151 | if (!reuse || !sk2->sk_reuse || | |
152 | sk2->sk_state == TCP_LISTEN) { | |
153 | const u32 sk2_rcv_saddr = tcp_v4_rcv_saddr(sk2); | |
154 | if (!sk2_rcv_saddr || !sk_rcv_saddr || | |
155 | sk2_rcv_saddr == sk_rcv_saddr) | |
156 | break; | |
157 | } | |
158 | } | |
159 | } | |
160 | return node != NULL; | |
161 | } | |
162 | ||
163 | /* Obtain a reference to a local port for the given sock, | |
164 | * if snum is zero it means select any available local port. | |
165 | */ | |
166 | static int tcp_v4_get_port(struct sock *sk, unsigned short snum) | |
167 | { | |
0f7ff927 | 168 | struct inet_bind_hashbucket *head; |
1da177e4 | 169 | struct hlist_node *node; |
0f7ff927 | 170 | struct inet_bind_bucket *tb; |
1da177e4 LT |
171 | int ret; |
172 | ||
173 | local_bh_disable(); | |
174 | if (!snum) { | |
175 | int low = sysctl_local_port_range[0]; | |
176 | int high = sysctl_local_port_range[1]; | |
177 | int remaining = (high - low) + 1; | |
178 | int rover; | |
179 | ||
180 | spin_lock(&tcp_portalloc_lock); | |
0b2531bd FH |
181 | if (tcp_port_rover < low) |
182 | rover = low; | |
183 | else | |
184 | rover = tcp_port_rover; | |
1da177e4 LT |
185 | do { |
186 | rover++; | |
0b2531bd | 187 | if (rover > high) |
1da177e4 | 188 | rover = low; |
0f7ff927 | 189 | head = &tcp_bhash[inet_bhashfn(rover, tcp_bhash_size)]; |
1da177e4 | 190 | spin_lock(&head->lock); |
0f7ff927 | 191 | inet_bind_bucket_for_each(tb, node, &head->chain) |
1da177e4 LT |
192 | if (tb->port == rover) |
193 | goto next; | |
194 | break; | |
195 | next: | |
196 | spin_unlock(&head->lock); | |
197 | } while (--remaining > 0); | |
198 | tcp_port_rover = rover; | |
199 | spin_unlock(&tcp_portalloc_lock); | |
200 | ||
d5d28375 DM |
201 | /* Exhausted local port range during search? It is not |
202 | * possible for us to be holding one of the bind hash | |
203 | * locks if this test triggers, because if 'remaining' | |
204 | * drops to zero, we broke out of the do/while loop at | |
205 | * the top level, not from the 'break;' statement. | |
206 | */ | |
1da177e4 | 207 | ret = 1; |
d5d28375 | 208 | if (unlikely(remaining <= 0)) |
1da177e4 LT |
209 | goto fail; |
210 | ||
211 | /* OK, here is the one we will use. HEAD is | |
212 | * non-NULL and we hold it's mutex. | |
213 | */ | |
214 | snum = rover; | |
215 | } else { | |
0f7ff927 | 216 | head = &tcp_bhash[inet_bhashfn(snum, tcp_bhash_size)]; |
1da177e4 | 217 | spin_lock(&head->lock); |
0f7ff927 | 218 | inet_bind_bucket_for_each(tb, node, &head->chain) |
1da177e4 LT |
219 | if (tb->port == snum) |
220 | goto tb_found; | |
221 | } | |
222 | tb = NULL; | |
223 | goto tb_not_found; | |
224 | tb_found: | |
225 | if (!hlist_empty(&tb->owners)) { | |
226 | if (sk->sk_reuse > 1) | |
227 | goto success; | |
228 | if (tb->fastreuse > 0 && | |
229 | sk->sk_reuse && sk->sk_state != TCP_LISTEN) { | |
230 | goto success; | |
231 | } else { | |
232 | ret = 1; | |
233 | if (tcp_bind_conflict(sk, tb)) | |
234 | goto fail_unlock; | |
235 | } | |
236 | } | |
237 | tb_not_found: | |
238 | ret = 1; | |
0f7ff927 | 239 | if (!tb && (tb = inet_bind_bucket_create(tcp_bucket_cachep, head, snum)) == NULL) |
1da177e4 LT |
240 | goto fail_unlock; |
241 | if (hlist_empty(&tb->owners)) { | |
242 | if (sk->sk_reuse && sk->sk_state != TCP_LISTEN) | |
243 | tb->fastreuse = 1; | |
244 | else | |
245 | tb->fastreuse = 0; | |
246 | } else if (tb->fastreuse && | |
247 | (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) | |
248 | tb->fastreuse = 0; | |
249 | success: | |
a55ebcc4 | 250 | if (!inet_sk(sk)->bind_hash) |
1da177e4 | 251 | tcp_bind_hash(sk, tb, snum); |
a55ebcc4 | 252 | BUG_TRAP(inet_sk(sk)->bind_hash == tb); |
1da177e4 LT |
253 | ret = 0; |
254 | ||
255 | fail_unlock: | |
256 | spin_unlock(&head->lock); | |
257 | fail: | |
258 | local_bh_enable(); | |
259 | return ret; | |
260 | } | |
261 | ||
262 | /* Get rid of any references to a local port held by the | |
263 | * given sock. | |
264 | */ | |
265 | static void __tcp_put_port(struct sock *sk) | |
266 | { | |
267 | struct inet_sock *inet = inet_sk(sk); | |
0f7ff927 ACM |
268 | struct inet_bind_hashbucket *head = &tcp_bhash[inet_bhashfn(inet->num, |
269 | tcp_bhash_size)]; | |
270 | struct inet_bind_bucket *tb; | |
1da177e4 LT |
271 | |
272 | spin_lock(&head->lock); | |
a55ebcc4 | 273 | tb = inet->bind_hash; |
1da177e4 | 274 | __sk_del_bind_node(sk); |
a55ebcc4 | 275 | inet->bind_hash = NULL; |
1da177e4 | 276 | inet->num = 0; |
0f7ff927 | 277 | inet_bind_bucket_destroy(tcp_bucket_cachep, tb); |
1da177e4 LT |
278 | spin_unlock(&head->lock); |
279 | } | |
280 | ||
281 | void tcp_put_port(struct sock *sk) | |
282 | { | |
283 | local_bh_disable(); | |
284 | __tcp_put_port(sk); | |
285 | local_bh_enable(); | |
286 | } | |
287 | ||
288 | /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP. | |
289 | * Look, when several writers sleep and reader wakes them up, all but one | |
290 | * immediately hit write lock and grab all the cpus. Exclusive sleep solves | |
291 | * this, _but_ remember, it adds useless work on UP machines (wake up each | |
292 | * exclusive lock release). It should be ifdefed really. | |
293 | */ | |
294 | ||
295 | void tcp_listen_wlock(void) | |
296 | { | |
297 | write_lock(&tcp_lhash_lock); | |
298 | ||
299 | if (atomic_read(&tcp_lhash_users)) { | |
300 | DEFINE_WAIT(wait); | |
301 | ||
302 | for (;;) { | |
303 | prepare_to_wait_exclusive(&tcp_lhash_wait, | |
304 | &wait, TASK_UNINTERRUPTIBLE); | |
305 | if (!atomic_read(&tcp_lhash_users)) | |
306 | break; | |
307 | write_unlock_bh(&tcp_lhash_lock); | |
308 | schedule(); | |
309 | write_lock_bh(&tcp_lhash_lock); | |
310 | } | |
311 | ||
312 | finish_wait(&tcp_lhash_wait, &wait); | |
313 | } | |
314 | } | |
315 | ||
316 | static __inline__ void __tcp_v4_hash(struct sock *sk, const int listen_possible) | |
317 | { | |
318 | struct hlist_head *list; | |
319 | rwlock_t *lock; | |
320 | ||
321 | BUG_TRAP(sk_unhashed(sk)); | |
322 | if (listen_possible && sk->sk_state == TCP_LISTEN) { | |
0f7ff927 | 323 | list = &tcp_listening_hash[inet_sk_listen_hashfn(sk)]; |
1da177e4 LT |
324 | lock = &tcp_lhash_lock; |
325 | tcp_listen_wlock(); | |
326 | } else { | |
304a1618 ACM |
327 | sk->sk_hashent = inet_sk_ehashfn(sk, tcp_ehash_size); |
328 | list = &tcp_ehash[sk->sk_hashent].chain; | |
1da177e4 LT |
329 | lock = &tcp_ehash[sk->sk_hashent].lock; |
330 | write_lock(lock); | |
331 | } | |
332 | __sk_add_node(sk, list); | |
333 | sock_prot_inc_use(sk->sk_prot); | |
334 | write_unlock(lock); | |
335 | if (listen_possible && sk->sk_state == TCP_LISTEN) | |
336 | wake_up(&tcp_lhash_wait); | |
337 | } | |
338 | ||
339 | static void tcp_v4_hash(struct sock *sk) | |
340 | { | |
341 | if (sk->sk_state != TCP_CLOSE) { | |
342 | local_bh_disable(); | |
343 | __tcp_v4_hash(sk, 1); | |
344 | local_bh_enable(); | |
345 | } | |
346 | } | |
347 | ||
348 | void tcp_unhash(struct sock *sk) | |
349 | { | |
350 | rwlock_t *lock; | |
351 | ||
352 | if (sk_unhashed(sk)) | |
353 | goto ende; | |
354 | ||
355 | if (sk->sk_state == TCP_LISTEN) { | |
356 | local_bh_disable(); | |
357 | tcp_listen_wlock(); | |
358 | lock = &tcp_lhash_lock; | |
359 | } else { | |
0f7ff927 | 360 | struct inet_ehash_bucket *head = &tcp_ehash[sk->sk_hashent]; |
1da177e4 LT |
361 | lock = &head->lock; |
362 | write_lock_bh(&head->lock); | |
363 | } | |
364 | ||
365 | if (__sk_del_node_init(sk)) | |
366 | sock_prot_dec_use(sk->sk_prot); | |
367 | write_unlock_bh(lock); | |
368 | ||
369 | ende: | |
370 | if (sk->sk_state == TCP_LISTEN) | |
371 | wake_up(&tcp_lhash_wait); | |
372 | } | |
373 | ||
374 | /* Don't inline this cruft. Here are some nice properties to | |
375 | * exploit here. The BSD API does not allow a listening TCP | |
376 | * to specify the remote port nor the remote address for the | |
377 | * connection. So always assume those are both wildcarded | |
378 | * during the search since they can never be otherwise. | |
379 | */ | |
0f7ff927 ACM |
380 | static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head, |
381 | const u32 daddr, | |
382 | const unsigned short hnum, | |
383 | const int dif) | |
1da177e4 LT |
384 | { |
385 | struct sock *result = NULL, *sk; | |
386 | struct hlist_node *node; | |
387 | int score, hiscore; | |
388 | ||
389 | hiscore=-1; | |
390 | sk_for_each(sk, node, head) { | |
391 | struct inet_sock *inet = inet_sk(sk); | |
392 | ||
393 | if (inet->num == hnum && !ipv6_only_sock(sk)) { | |
394 | __u32 rcv_saddr = inet->rcv_saddr; | |
395 | ||
396 | score = (sk->sk_family == PF_INET ? 1 : 0); | |
397 | if (rcv_saddr) { | |
398 | if (rcv_saddr != daddr) | |
399 | continue; | |
400 | score+=2; | |
401 | } | |
402 | if (sk->sk_bound_dev_if) { | |
403 | if (sk->sk_bound_dev_if != dif) | |
404 | continue; | |
405 | score+=2; | |
406 | } | |
407 | if (score == 5) | |
408 | return sk; | |
409 | if (score > hiscore) { | |
410 | hiscore = score; | |
411 | result = sk; | |
412 | } | |
413 | } | |
414 | } | |
415 | return result; | |
416 | } | |
417 | ||
418 | /* Optimize the common listener case. */ | |
0f7ff927 ACM |
419 | static inline struct sock *tcp_v4_lookup_listener(const u32 daddr, |
420 | const unsigned short hnum, | |
421 | const int dif) | |
1da177e4 LT |
422 | { |
423 | struct sock *sk = NULL; | |
424 | struct hlist_head *head; | |
425 | ||
426 | read_lock(&tcp_lhash_lock); | |
0f7ff927 | 427 | head = &tcp_listening_hash[inet_lhashfn(hnum)]; |
1da177e4 LT |
428 | if (!hlist_empty(head)) { |
429 | struct inet_sock *inet = inet_sk((sk = __sk_head(head))); | |
430 | ||
431 | if (inet->num == hnum && !sk->sk_node.next && | |
432 | (!inet->rcv_saddr || inet->rcv_saddr == daddr) && | |
433 | (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) && | |
434 | !sk->sk_bound_dev_if) | |
435 | goto sherry_cache; | |
436 | sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif); | |
437 | } | |
438 | if (sk) { | |
439 | sherry_cache: | |
440 | sock_hold(sk); | |
441 | } | |
442 | read_unlock(&tcp_lhash_lock); | |
443 | return sk; | |
444 | } | |
445 | ||
446 | /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so | |
447 | * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM | |
448 | * | |
449 | * Local BH must be disabled here. | |
450 | */ | |
451 | ||
0f7ff927 ACM |
452 | static inline struct sock *__tcp_v4_lookup_established(const u32 saddr, |
453 | const u16 sport, | |
454 | const u32 daddr, | |
455 | const u16 hnum, | |
456 | const int dif) | |
1da177e4 | 457 | { |
0f7ff927 | 458 | struct inet_ehash_bucket *head; |
1da177e4 LT |
459 | TCP_V4_ADDR_COOKIE(acookie, saddr, daddr) |
460 | __u32 ports = TCP_COMBINED_PORTS(sport, hnum); | |
461 | struct sock *sk; | |
462 | struct hlist_node *node; | |
463 | /* Optimize here for direct hit, only listening connections can | |
464 | * have wildcards anyways. | |
465 | */ | |
304a1618 | 466 | const int hash = inet_ehashfn(daddr, hnum, saddr, sport, tcp_ehash_size); |
1da177e4 LT |
467 | head = &tcp_ehash[hash]; |
468 | read_lock(&head->lock); | |
469 | sk_for_each(sk, node, &head->chain) { | |
470 | if (TCP_IPV4_MATCH(sk, acookie, saddr, daddr, ports, dif)) | |
471 | goto hit; /* You sunk my battleship! */ | |
472 | } | |
473 | ||
474 | /* Must check for a TIME_WAIT'er before going to listener hash. */ | |
475 | sk_for_each(sk, node, &(head + tcp_ehash_size)->chain) { | |
476 | if (TCP_IPV4_TW_MATCH(sk, acookie, saddr, daddr, ports, dif)) | |
477 | goto hit; | |
478 | } | |
479 | sk = NULL; | |
480 | out: | |
481 | read_unlock(&head->lock); | |
482 | return sk; | |
483 | hit: | |
484 | sock_hold(sk); | |
485 | goto out; | |
486 | } | |
487 | ||
488 | static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport, | |
489 | u32 daddr, u16 hnum, int dif) | |
490 | { | |
491 | struct sock *sk = __tcp_v4_lookup_established(saddr, sport, | |
492 | daddr, hnum, dif); | |
493 | ||
494 | return sk ? : tcp_v4_lookup_listener(daddr, hnum, dif); | |
495 | } | |
496 | ||
497 | inline struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr, | |
498 | u16 dport, int dif) | |
499 | { | |
500 | struct sock *sk; | |
501 | ||
502 | local_bh_disable(); | |
503 | sk = __tcp_v4_lookup(saddr, sport, daddr, ntohs(dport), dif); | |
504 | local_bh_enable(); | |
505 | ||
506 | return sk; | |
507 | } | |
508 | ||
509 | EXPORT_SYMBOL_GPL(tcp_v4_lookup); | |
510 | ||
511 | static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb) | |
512 | { | |
513 | return secure_tcp_sequence_number(skb->nh.iph->daddr, | |
514 | skb->nh.iph->saddr, | |
515 | skb->h.th->dest, | |
516 | skb->h.th->source); | |
517 | } | |
518 | ||
519 | /* called with local bh disabled */ | |
520 | static int __tcp_v4_check_established(struct sock *sk, __u16 lport, | |
521 | struct tcp_tw_bucket **twp) | |
522 | { | |
523 | struct inet_sock *inet = inet_sk(sk); | |
524 | u32 daddr = inet->rcv_saddr; | |
525 | u32 saddr = inet->daddr; | |
526 | int dif = sk->sk_bound_dev_if; | |
527 | TCP_V4_ADDR_COOKIE(acookie, saddr, daddr) | |
528 | __u32 ports = TCP_COMBINED_PORTS(inet->dport, lport); | |
304a1618 | 529 | const int hash = inet_ehashfn(daddr, lport, saddr, inet->dport, tcp_ehash_size); |
0f7ff927 | 530 | struct inet_ehash_bucket *head = &tcp_ehash[hash]; |
1da177e4 LT |
531 | struct sock *sk2; |
532 | struct hlist_node *node; | |
533 | struct tcp_tw_bucket *tw; | |
534 | ||
535 | write_lock(&head->lock); | |
536 | ||
537 | /* Check TIME-WAIT sockets first. */ | |
538 | sk_for_each(sk2, node, &(head + tcp_ehash_size)->chain) { | |
539 | tw = (struct tcp_tw_bucket *)sk2; | |
540 | ||
541 | if (TCP_IPV4_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) { | |
542 | struct tcp_sock *tp = tcp_sk(sk); | |
543 | ||
544 | /* With PAWS, it is safe from the viewpoint | |
545 | of data integrity. Even without PAWS it | |
546 | is safe provided sequence spaces do not | |
547 | overlap i.e. at data rates <= 80Mbit/sec. | |
548 | ||
549 | Actually, the idea is close to VJ's one, | |
550 | only timestamp cache is held not per host, | |
551 | but per port pair and TW bucket is used | |
552 | as state holder. | |
553 | ||
554 | If TW bucket has been already destroyed we | |
555 | fall back to VJ's scheme and use initial | |
556 | timestamp retrieved from peer table. | |
557 | */ | |
558 | if (tw->tw_ts_recent_stamp && | |
559 | (!twp || (sysctl_tcp_tw_reuse && | |
560 | xtime.tv_sec - | |
561 | tw->tw_ts_recent_stamp > 1))) { | |
562 | if ((tp->write_seq = | |
563 | tw->tw_snd_nxt + 65535 + 2) == 0) | |
564 | tp->write_seq = 1; | |
565 | tp->rx_opt.ts_recent = tw->tw_ts_recent; | |
566 | tp->rx_opt.ts_recent_stamp = tw->tw_ts_recent_stamp; | |
567 | sock_hold(sk2); | |
568 | goto unique; | |
569 | } else | |
570 | goto not_unique; | |
571 | } | |
572 | } | |
573 | tw = NULL; | |
574 | ||
575 | /* And established part... */ | |
576 | sk_for_each(sk2, node, &head->chain) { | |
577 | if (TCP_IPV4_MATCH(sk2, acookie, saddr, daddr, ports, dif)) | |
578 | goto not_unique; | |
579 | } | |
580 | ||
581 | unique: | |
582 | /* Must record num and sport now. Otherwise we will see | |
583 | * in hash table socket with a funny identity. */ | |
584 | inet->num = lport; | |
585 | inet->sport = htons(lport); | |
586 | sk->sk_hashent = hash; | |
587 | BUG_TRAP(sk_unhashed(sk)); | |
588 | __sk_add_node(sk, &head->chain); | |
589 | sock_prot_inc_use(sk->sk_prot); | |
590 | write_unlock(&head->lock); | |
591 | ||
592 | if (twp) { | |
593 | *twp = tw; | |
594 | NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); | |
595 | } else if (tw) { | |
596 | /* Silly. Should hash-dance instead... */ | |
597 | tcp_tw_deschedule(tw); | |
598 | NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); | |
599 | ||
600 | tcp_tw_put(tw); | |
601 | } | |
602 | ||
603 | return 0; | |
604 | ||
605 | not_unique: | |
606 | write_unlock(&head->lock); | |
607 | return -EADDRNOTAVAIL; | |
608 | } | |
609 | ||
610 | static inline u32 connect_port_offset(const struct sock *sk) | |
611 | { | |
612 | const struct inet_sock *inet = inet_sk(sk); | |
613 | ||
614 | return secure_tcp_port_ephemeral(inet->rcv_saddr, inet->daddr, | |
615 | inet->dport); | |
616 | } | |
617 | ||
618 | /* | |
619 | * Bind a port for a connect operation and hash it. | |
620 | */ | |
621 | static inline int tcp_v4_hash_connect(struct sock *sk) | |
622 | { | |
0f7ff927 ACM |
623 | const unsigned short snum = inet_sk(sk)->num; |
624 | struct inet_bind_hashbucket *head; | |
625 | struct inet_bind_bucket *tb; | |
1da177e4 LT |
626 | int ret; |
627 | ||
628 | if (!snum) { | |
629 | int low = sysctl_local_port_range[0]; | |
630 | int high = sysctl_local_port_range[1]; | |
631 | int range = high - low; | |
632 | int i; | |
633 | int port; | |
634 | static u32 hint; | |
635 | u32 offset = hint + connect_port_offset(sk); | |
636 | struct hlist_node *node; | |
637 | struct tcp_tw_bucket *tw = NULL; | |
638 | ||
639 | local_bh_disable(); | |
640 | for (i = 1; i <= range; i++) { | |
641 | port = low + (i + offset) % range; | |
0f7ff927 | 642 | head = &tcp_bhash[inet_bhashfn(port, tcp_bhash_size)]; |
1da177e4 LT |
643 | spin_lock(&head->lock); |
644 | ||
645 | /* Does not bother with rcv_saddr checks, | |
646 | * because the established check is already | |
647 | * unique enough. | |
648 | */ | |
0f7ff927 | 649 | inet_bind_bucket_for_each(tb, node, &head->chain) { |
1da177e4 LT |
650 | if (tb->port == port) { |
651 | BUG_TRAP(!hlist_empty(&tb->owners)); | |
652 | if (tb->fastreuse >= 0) | |
653 | goto next_port; | |
654 | if (!__tcp_v4_check_established(sk, | |
655 | port, | |
656 | &tw)) | |
657 | goto ok; | |
658 | goto next_port; | |
659 | } | |
660 | } | |
661 | ||
0f7ff927 | 662 | tb = inet_bind_bucket_create(tcp_bucket_cachep, head, port); |
1da177e4 LT |
663 | if (!tb) { |
664 | spin_unlock(&head->lock); | |
665 | break; | |
666 | } | |
667 | tb->fastreuse = -1; | |
668 | goto ok; | |
669 | ||
670 | next_port: | |
671 | spin_unlock(&head->lock); | |
672 | } | |
673 | local_bh_enable(); | |
674 | ||
675 | return -EADDRNOTAVAIL; | |
676 | ||
677 | ok: | |
678 | hint += i; | |
679 | ||
680 | /* Head lock still held and bh's disabled */ | |
681 | tcp_bind_hash(sk, tb, port); | |
682 | if (sk_unhashed(sk)) { | |
683 | inet_sk(sk)->sport = htons(port); | |
684 | __tcp_v4_hash(sk, 0); | |
685 | } | |
686 | spin_unlock(&head->lock); | |
687 | ||
688 | if (tw) { | |
689 | tcp_tw_deschedule(tw); | |
690 | tcp_tw_put(tw); | |
691 | } | |
692 | ||
693 | ret = 0; | |
694 | goto out; | |
695 | } | |
696 | ||
0f7ff927 | 697 | head = &tcp_bhash[inet_bhashfn(snum, tcp_bhash_size)]; |
a55ebcc4 | 698 | tb = inet_sk(sk)->bind_hash; |
1da177e4 LT |
699 | spin_lock_bh(&head->lock); |
700 | if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { | |
701 | __tcp_v4_hash(sk, 0); | |
702 | spin_unlock_bh(&head->lock); | |
703 | return 0; | |
704 | } else { | |
705 | spin_unlock(&head->lock); | |
706 | /* No definite answer... Walk to established hash table */ | |
707 | ret = __tcp_v4_check_established(sk, snum, NULL); | |
708 | out: | |
709 | local_bh_enable(); | |
710 | return ret; | |
711 | } | |
712 | } | |
713 | ||
714 | /* This will initiate an outgoing connection. */ | |
715 | int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) | |
716 | { | |
717 | struct inet_sock *inet = inet_sk(sk); | |
718 | struct tcp_sock *tp = tcp_sk(sk); | |
719 | struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; | |
720 | struct rtable *rt; | |
721 | u32 daddr, nexthop; | |
722 | int tmp; | |
723 | int err; | |
724 | ||
725 | if (addr_len < sizeof(struct sockaddr_in)) | |
726 | return -EINVAL; | |
727 | ||
728 | if (usin->sin_family != AF_INET) | |
729 | return -EAFNOSUPPORT; | |
730 | ||
731 | nexthop = daddr = usin->sin_addr.s_addr; | |
732 | if (inet->opt && inet->opt->srr) { | |
733 | if (!daddr) | |
734 | return -EINVAL; | |
735 | nexthop = inet->opt->faddr; | |
736 | } | |
737 | ||
738 | tmp = ip_route_connect(&rt, nexthop, inet->saddr, | |
739 | RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, | |
740 | IPPROTO_TCP, | |
741 | inet->sport, usin->sin_port, sk); | |
742 | if (tmp < 0) | |
743 | return tmp; | |
744 | ||
745 | if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { | |
746 | ip_rt_put(rt); | |
747 | return -ENETUNREACH; | |
748 | } | |
749 | ||
750 | if (!inet->opt || !inet->opt->srr) | |
751 | daddr = rt->rt_dst; | |
752 | ||
753 | if (!inet->saddr) | |
754 | inet->saddr = rt->rt_src; | |
755 | inet->rcv_saddr = inet->saddr; | |
756 | ||
757 | if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) { | |
758 | /* Reset inherited state */ | |
759 | tp->rx_opt.ts_recent = 0; | |
760 | tp->rx_opt.ts_recent_stamp = 0; | |
761 | tp->write_seq = 0; | |
762 | } | |
763 | ||
764 | if (sysctl_tcp_tw_recycle && | |
765 | !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) { | |
766 | struct inet_peer *peer = rt_get_peer(rt); | |
767 | ||
768 | /* VJ's idea. We save last timestamp seen from | |
769 | * the destination in peer table, when entering state TIME-WAIT | |
770 | * and initialize rx_opt.ts_recent from it, when trying new connection. | |
771 | */ | |
772 | ||
773 | if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) { | |
774 | tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; | |
775 | tp->rx_opt.ts_recent = peer->tcp_ts; | |
776 | } | |
777 | } | |
778 | ||
779 | inet->dport = usin->sin_port; | |
780 | inet->daddr = daddr; | |
781 | ||
782 | tp->ext_header_len = 0; | |
783 | if (inet->opt) | |
784 | tp->ext_header_len = inet->opt->optlen; | |
785 | ||
786 | tp->rx_opt.mss_clamp = 536; | |
787 | ||
788 | /* Socket identity is still unknown (sport may be zero). | |
789 | * However we set state to SYN-SENT and not releasing socket | |
790 | * lock select source port, enter ourselves into the hash tables and | |
791 | * complete initialization after this. | |
792 | */ | |
793 | tcp_set_state(sk, TCP_SYN_SENT); | |
794 | err = tcp_v4_hash_connect(sk); | |
795 | if (err) | |
796 | goto failure; | |
797 | ||
798 | err = ip_route_newports(&rt, inet->sport, inet->dport, sk); | |
799 | if (err) | |
800 | goto failure; | |
801 | ||
802 | /* OK, now commit destination to socket. */ | |
6cbb0df7 | 803 | sk_setup_caps(sk, &rt->u.dst); |
1da177e4 LT |
804 | |
805 | if (!tp->write_seq) | |
806 | tp->write_seq = secure_tcp_sequence_number(inet->saddr, | |
807 | inet->daddr, | |
808 | inet->sport, | |
809 | usin->sin_port); | |
810 | ||
811 | inet->id = tp->write_seq ^ jiffies; | |
812 | ||
813 | err = tcp_connect(sk); | |
814 | rt = NULL; | |
815 | if (err) | |
816 | goto failure; | |
817 | ||
818 | return 0; | |
819 | ||
820 | failure: | |
821 | /* This unhashes the socket and releases the local port, if necessary. */ | |
822 | tcp_set_state(sk, TCP_CLOSE); | |
823 | ip_rt_put(rt); | |
824 | sk->sk_route_caps = 0; | |
825 | inet->dport = 0; | |
826 | return err; | |
827 | } | |
828 | ||
829 | static __inline__ int tcp_v4_iif(struct sk_buff *skb) | |
830 | { | |
831 | return ((struct rtable *)skb->dst)->rt_iif; | |
832 | } | |
833 | ||
834 | static __inline__ u32 tcp_v4_synq_hash(u32 raddr, u16 rport, u32 rnd) | |
835 | { | |
836 | return (jhash_2words(raddr, (u32) rport, rnd) & (TCP_SYNQ_HSIZE - 1)); | |
837 | } | |
838 | ||
60236fdd ACM |
839 | static struct request_sock *tcp_v4_search_req(struct tcp_sock *tp, |
840 | struct request_sock ***prevp, | |
1da177e4 LT |
841 | __u16 rport, |
842 | __u32 raddr, __u32 laddr) | |
843 | { | |
2ad69c55 | 844 | struct listen_sock *lopt = tp->accept_queue.listen_opt; |
60236fdd | 845 | struct request_sock *req, **prev; |
1da177e4 LT |
846 | |
847 | for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport, lopt->hash_rnd)]; | |
848 | (req = *prev) != NULL; | |
849 | prev = &req->dl_next) { | |
2e6599cb ACM |
850 | const struct inet_request_sock *ireq = inet_rsk(req); |
851 | ||
852 | if (ireq->rmt_port == rport && | |
853 | ireq->rmt_addr == raddr && | |
854 | ireq->loc_addr == laddr && | |
60236fdd | 855 | TCP_INET_FAMILY(req->rsk_ops->family)) { |
1da177e4 LT |
856 | BUG_TRAP(!req->sk); |
857 | *prevp = prev; | |
858 | break; | |
859 | } | |
860 | } | |
861 | ||
862 | return req; | |
863 | } | |
864 | ||
60236fdd | 865 | static void tcp_v4_synq_add(struct sock *sk, struct request_sock *req) |
1da177e4 LT |
866 | { |
867 | struct tcp_sock *tp = tcp_sk(sk); | |
2ad69c55 | 868 | struct listen_sock *lopt = tp->accept_queue.listen_opt; |
2e6599cb | 869 | u32 h = tcp_v4_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, lopt->hash_rnd); |
1da177e4 | 870 | |
0e87506f | 871 | reqsk_queue_hash_req(&tp->accept_queue, h, req, TCP_TIMEOUT_INIT); |
1da177e4 LT |
872 | tcp_synq_added(sk); |
873 | } | |
874 | ||
875 | ||
876 | /* | |
877 | * This routine does path mtu discovery as defined in RFC1191. | |
878 | */ | |
879 | static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, | |
880 | u32 mtu) | |
881 | { | |
882 | struct dst_entry *dst; | |
883 | struct inet_sock *inet = inet_sk(sk); | |
884 | struct tcp_sock *tp = tcp_sk(sk); | |
885 | ||
886 | /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs | |
887 | * send out by Linux are always <576bytes so they should go through | |
888 | * unfragmented). | |
889 | */ | |
890 | if (sk->sk_state == TCP_LISTEN) | |
891 | return; | |
892 | ||
893 | /* We don't check in the destentry if pmtu discovery is forbidden | |
894 | * on this route. We just assume that no packet_to_big packets | |
895 | * are send back when pmtu discovery is not active. | |
896 | * There is a small race when the user changes this flag in the | |
897 | * route, but I think that's acceptable. | |
898 | */ | |
899 | if ((dst = __sk_dst_check(sk, 0)) == NULL) | |
900 | return; | |
901 | ||
902 | dst->ops->update_pmtu(dst, mtu); | |
903 | ||
904 | /* Something is about to be wrong... Remember soft error | |
905 | * for the case, if this connection will not able to recover. | |
906 | */ | |
907 | if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) | |
908 | sk->sk_err_soft = EMSGSIZE; | |
909 | ||
910 | mtu = dst_mtu(dst); | |
911 | ||
912 | if (inet->pmtudisc != IP_PMTUDISC_DONT && | |
913 | tp->pmtu_cookie > mtu) { | |
914 | tcp_sync_mss(sk, mtu); | |
915 | ||
916 | /* Resend the TCP packet because it's | |
917 | * clear that the old packet has been | |
918 | * dropped. This is the new "fast" path mtu | |
919 | * discovery. | |
920 | */ | |
921 | tcp_simple_retransmit(sk); | |
922 | } /* else let the usual retransmit timer handle it */ | |
923 | } | |
924 | ||
925 | /* | |
926 | * This routine is called by the ICMP module when it gets some | |
927 | * sort of error condition. If err < 0 then the socket should | |
928 | * be closed and the error returned to the user. If err > 0 | |
929 | * it's just the icmp type << 8 | icmp code. After adjustment | |
930 | * header points to the first 8 bytes of the tcp header. We need | |
931 | * to find the appropriate port. | |
932 | * | |
933 | * The locking strategy used here is very "optimistic". When | |
934 | * someone else accesses the socket the ICMP is just dropped | |
935 | * and for some paths there is no check at all. | |
936 | * A more general error queue to queue errors for later handling | |
937 | * is probably better. | |
938 | * | |
939 | */ | |
940 | ||
941 | void tcp_v4_err(struct sk_buff *skb, u32 info) | |
942 | { | |
943 | struct iphdr *iph = (struct iphdr *)skb->data; | |
944 | struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2)); | |
945 | struct tcp_sock *tp; | |
946 | struct inet_sock *inet; | |
947 | int type = skb->h.icmph->type; | |
948 | int code = skb->h.icmph->code; | |
949 | struct sock *sk; | |
950 | __u32 seq; | |
951 | int err; | |
952 | ||
953 | if (skb->len < (iph->ihl << 2) + 8) { | |
954 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
955 | return; | |
956 | } | |
957 | ||
958 | sk = tcp_v4_lookup(iph->daddr, th->dest, iph->saddr, | |
959 | th->source, tcp_v4_iif(skb)); | |
960 | if (!sk) { | |
961 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
962 | return; | |
963 | } | |
964 | if (sk->sk_state == TCP_TIME_WAIT) { | |
965 | tcp_tw_put((struct tcp_tw_bucket *)sk); | |
966 | return; | |
967 | } | |
968 | ||
969 | bh_lock_sock(sk); | |
970 | /* If too many ICMPs get dropped on busy | |
971 | * servers this needs to be solved differently. | |
972 | */ | |
973 | if (sock_owned_by_user(sk)) | |
974 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
975 | ||
976 | if (sk->sk_state == TCP_CLOSE) | |
977 | goto out; | |
978 | ||
979 | tp = tcp_sk(sk); | |
980 | seq = ntohl(th->seq); | |
981 | if (sk->sk_state != TCP_LISTEN && | |
982 | !between(seq, tp->snd_una, tp->snd_nxt)) { | |
983 | NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS); | |
984 | goto out; | |
985 | } | |
986 | ||
987 | switch (type) { | |
988 | case ICMP_SOURCE_QUENCH: | |
989 | /* Just silently ignore these. */ | |
990 | goto out; | |
991 | case ICMP_PARAMETERPROB: | |
992 | err = EPROTO; | |
993 | break; | |
994 | case ICMP_DEST_UNREACH: | |
995 | if (code > NR_ICMP_UNREACH) | |
996 | goto out; | |
997 | ||
998 | if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ | |
999 | if (!sock_owned_by_user(sk)) | |
1000 | do_pmtu_discovery(sk, iph, info); | |
1001 | goto out; | |
1002 | } | |
1003 | ||
1004 | err = icmp_err_convert[code].errno; | |
1005 | break; | |
1006 | case ICMP_TIME_EXCEEDED: | |
1007 | err = EHOSTUNREACH; | |
1008 | break; | |
1009 | default: | |
1010 | goto out; | |
1011 | } | |
1012 | ||
1013 | switch (sk->sk_state) { | |
60236fdd | 1014 | struct request_sock *req, **prev; |
1da177e4 LT |
1015 | case TCP_LISTEN: |
1016 | if (sock_owned_by_user(sk)) | |
1017 | goto out; | |
1018 | ||
1019 | req = tcp_v4_search_req(tp, &prev, th->dest, | |
1020 | iph->daddr, iph->saddr); | |
1021 | if (!req) | |
1022 | goto out; | |
1023 | ||
1024 | /* ICMPs are not backlogged, hence we cannot get | |
1025 | an established socket here. | |
1026 | */ | |
1027 | BUG_TRAP(!req->sk); | |
1028 | ||
2e6599cb | 1029 | if (seq != tcp_rsk(req)->snt_isn) { |
1da177e4 LT |
1030 | NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS); |
1031 | goto out; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * Still in SYN_RECV, just remove it silently. | |
1036 | * There is no good way to pass the error to the newly | |
1037 | * created socket, and POSIX does not want network | |
1038 | * errors returned from accept(). | |
1039 | */ | |
1040 | tcp_synq_drop(sk, req, prev); | |
1041 | goto out; | |
1042 | ||
1043 | case TCP_SYN_SENT: | |
1044 | case TCP_SYN_RECV: /* Cannot happen. | |
1045 | It can f.e. if SYNs crossed. | |
1046 | */ | |
1047 | if (!sock_owned_by_user(sk)) { | |
1048 | TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); | |
1049 | sk->sk_err = err; | |
1050 | ||
1051 | sk->sk_error_report(sk); | |
1052 | ||
1053 | tcp_done(sk); | |
1054 | } else { | |
1055 | sk->sk_err_soft = err; | |
1056 | } | |
1057 | goto out; | |
1058 | } | |
1059 | ||
1060 | /* If we've already connected we will keep trying | |
1061 | * until we time out, or the user gives up. | |
1062 | * | |
1063 | * rfc1122 4.2.3.9 allows to consider as hard errors | |
1064 | * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, | |
1065 | * but it is obsoleted by pmtu discovery). | |
1066 | * | |
1067 | * Note, that in modern internet, where routing is unreliable | |
1068 | * and in each dark corner broken firewalls sit, sending random | |
1069 | * errors ordered by their masters even this two messages finally lose | |
1070 | * their original sense (even Linux sends invalid PORT_UNREACHs) | |
1071 | * | |
1072 | * Now we are in compliance with RFCs. | |
1073 | * --ANK (980905) | |
1074 | */ | |
1075 | ||
1076 | inet = inet_sk(sk); | |
1077 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
1078 | sk->sk_err = err; | |
1079 | sk->sk_error_report(sk); | |
1080 | } else { /* Only an error on timeout */ | |
1081 | sk->sk_err_soft = err; | |
1082 | } | |
1083 | ||
1084 | out: | |
1085 | bh_unlock_sock(sk); | |
1086 | sock_put(sk); | |
1087 | } | |
1088 | ||
1089 | /* This routine computes an IPv4 TCP checksum. */ | |
1090 | void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len, | |
1091 | struct sk_buff *skb) | |
1092 | { | |
1093 | struct inet_sock *inet = inet_sk(sk); | |
1094 | ||
1095 | if (skb->ip_summed == CHECKSUM_HW) { | |
1096 | th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0); | |
1097 | skb->csum = offsetof(struct tcphdr, check); | |
1098 | } else { | |
1099 | th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr, | |
1100 | csum_partial((char *)th, | |
1101 | th->doff << 2, | |
1102 | skb->csum)); | |
1103 | } | |
1104 | } | |
1105 | ||
1106 | /* | |
1107 | * This routine will send an RST to the other tcp. | |
1108 | * | |
1109 | * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) | |
1110 | * for reset. | |
1111 | * Answer: if a packet caused RST, it is not for a socket | |
1112 | * existing in our system, if it is matched to a socket, | |
1113 | * it is just duplicate segment or bug in other side's TCP. | |
1114 | * So that we build reply only basing on parameters | |
1115 | * arrived with segment. | |
1116 | * Exception: precedence violation. We do not implement it in any case. | |
1117 | */ | |
1118 | ||
1119 | static void tcp_v4_send_reset(struct sk_buff *skb) | |
1120 | { | |
1121 | struct tcphdr *th = skb->h.th; | |
1122 | struct tcphdr rth; | |
1123 | struct ip_reply_arg arg; | |
1124 | ||
1125 | /* Never send a reset in response to a reset. */ | |
1126 | if (th->rst) | |
1127 | return; | |
1128 | ||
1129 | if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL) | |
1130 | return; | |
1131 | ||
1132 | /* Swap the send and the receive. */ | |
1133 | memset(&rth, 0, sizeof(struct tcphdr)); | |
1134 | rth.dest = th->source; | |
1135 | rth.source = th->dest; | |
1136 | rth.doff = sizeof(struct tcphdr) / 4; | |
1137 | rth.rst = 1; | |
1138 | ||
1139 | if (th->ack) { | |
1140 | rth.seq = th->ack_seq; | |
1141 | } else { | |
1142 | rth.ack = 1; | |
1143 | rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + | |
1144 | skb->len - (th->doff << 2)); | |
1145 | } | |
1146 | ||
1147 | memset(&arg, 0, sizeof arg); | |
1148 | arg.iov[0].iov_base = (unsigned char *)&rth; | |
1149 | arg.iov[0].iov_len = sizeof rth; | |
1150 | arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, | |
1151 | skb->nh.iph->saddr, /*XXX*/ | |
1152 | sizeof(struct tcphdr), IPPROTO_TCP, 0); | |
1153 | arg.csumoffset = offsetof(struct tcphdr, check) / 2; | |
1154 | ||
1155 | ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth); | |
1156 | ||
1157 | TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); | |
1158 | TCP_INC_STATS_BH(TCP_MIB_OUTRSTS); | |
1159 | } | |
1160 | ||
1161 | /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states | |
1162 | outside socket context is ugly, certainly. What can I do? | |
1163 | */ | |
1164 | ||
1165 | static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, | |
1166 | u32 win, u32 ts) | |
1167 | { | |
1168 | struct tcphdr *th = skb->h.th; | |
1169 | struct { | |
1170 | struct tcphdr th; | |
1171 | u32 tsopt[3]; | |
1172 | } rep; | |
1173 | struct ip_reply_arg arg; | |
1174 | ||
1175 | memset(&rep.th, 0, sizeof(struct tcphdr)); | |
1176 | memset(&arg, 0, sizeof arg); | |
1177 | ||
1178 | arg.iov[0].iov_base = (unsigned char *)&rep; | |
1179 | arg.iov[0].iov_len = sizeof(rep.th); | |
1180 | if (ts) { | |
1181 | rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | | |
1182 | (TCPOPT_TIMESTAMP << 8) | | |
1183 | TCPOLEN_TIMESTAMP); | |
1184 | rep.tsopt[1] = htonl(tcp_time_stamp); | |
1185 | rep.tsopt[2] = htonl(ts); | |
1186 | arg.iov[0].iov_len = sizeof(rep); | |
1187 | } | |
1188 | ||
1189 | /* Swap the send and the receive. */ | |
1190 | rep.th.dest = th->source; | |
1191 | rep.th.source = th->dest; | |
1192 | rep.th.doff = arg.iov[0].iov_len / 4; | |
1193 | rep.th.seq = htonl(seq); | |
1194 | rep.th.ack_seq = htonl(ack); | |
1195 | rep.th.ack = 1; | |
1196 | rep.th.window = htons(win); | |
1197 | ||
1198 | arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, | |
1199 | skb->nh.iph->saddr, /*XXX*/ | |
1200 | arg.iov[0].iov_len, IPPROTO_TCP, 0); | |
1201 | arg.csumoffset = offsetof(struct tcphdr, check) / 2; | |
1202 | ||
1203 | ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len); | |
1204 | ||
1205 | TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); | |
1206 | } | |
1207 | ||
1208 | static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) | |
1209 | { | |
1210 | struct tcp_tw_bucket *tw = (struct tcp_tw_bucket *)sk; | |
1211 | ||
1212 | tcp_v4_send_ack(skb, tw->tw_snd_nxt, tw->tw_rcv_nxt, | |
1213 | tw->tw_rcv_wnd >> tw->tw_rcv_wscale, tw->tw_ts_recent); | |
1214 | ||
1215 | tcp_tw_put(tw); | |
1216 | } | |
1217 | ||
60236fdd | 1218 | static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req) |
1da177e4 | 1219 | { |
2e6599cb | 1220 | tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, |
1da177e4 LT |
1221 | req->ts_recent); |
1222 | } | |
1223 | ||
1224 | static struct dst_entry* tcp_v4_route_req(struct sock *sk, | |
60236fdd | 1225 | struct request_sock *req) |
1da177e4 LT |
1226 | { |
1227 | struct rtable *rt; | |
2e6599cb ACM |
1228 | const struct inet_request_sock *ireq = inet_rsk(req); |
1229 | struct ip_options *opt = inet_rsk(req)->opt; | |
1da177e4 LT |
1230 | struct flowi fl = { .oif = sk->sk_bound_dev_if, |
1231 | .nl_u = { .ip4_u = | |
1232 | { .daddr = ((opt && opt->srr) ? | |
1233 | opt->faddr : | |
2e6599cb ACM |
1234 | ireq->rmt_addr), |
1235 | .saddr = ireq->loc_addr, | |
1da177e4 LT |
1236 | .tos = RT_CONN_FLAGS(sk) } }, |
1237 | .proto = IPPROTO_TCP, | |
1238 | .uli_u = { .ports = | |
1239 | { .sport = inet_sk(sk)->sport, | |
2e6599cb | 1240 | .dport = ireq->rmt_port } } }; |
1da177e4 LT |
1241 | |
1242 | if (ip_route_output_flow(&rt, &fl, sk, 0)) { | |
1243 | IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); | |
1244 | return NULL; | |
1245 | } | |
1246 | if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) { | |
1247 | ip_rt_put(rt); | |
1248 | IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); | |
1249 | return NULL; | |
1250 | } | |
1251 | return &rt->u.dst; | |
1252 | } | |
1253 | ||
1254 | /* | |
1255 | * Send a SYN-ACK after having received an ACK. | |
60236fdd | 1256 | * This still operates on a request_sock only, not on a big |
1da177e4 LT |
1257 | * socket. |
1258 | */ | |
60236fdd | 1259 | static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req, |
1da177e4 LT |
1260 | struct dst_entry *dst) |
1261 | { | |
2e6599cb | 1262 | const struct inet_request_sock *ireq = inet_rsk(req); |
1da177e4 LT |
1263 | int err = -1; |
1264 | struct sk_buff * skb; | |
1265 | ||
1266 | /* First, grab a route. */ | |
1267 | if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL) | |
1268 | goto out; | |
1269 | ||
1270 | skb = tcp_make_synack(sk, dst, req); | |
1271 | ||
1272 | if (skb) { | |
1273 | struct tcphdr *th = skb->h.th; | |
1274 | ||
1275 | th->check = tcp_v4_check(th, skb->len, | |
2e6599cb ACM |
1276 | ireq->loc_addr, |
1277 | ireq->rmt_addr, | |
1da177e4 LT |
1278 | csum_partial((char *)th, skb->len, |
1279 | skb->csum)); | |
1280 | ||
2e6599cb ACM |
1281 | err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, |
1282 | ireq->rmt_addr, | |
1283 | ireq->opt); | |
1da177e4 LT |
1284 | if (err == NET_XMIT_CN) |
1285 | err = 0; | |
1286 | } | |
1287 | ||
1288 | out: | |
1289 | dst_release(dst); | |
1290 | return err; | |
1291 | } | |
1292 | ||
1293 | /* | |
60236fdd | 1294 | * IPv4 request_sock destructor. |
1da177e4 | 1295 | */ |
60236fdd | 1296 | static void tcp_v4_reqsk_destructor(struct request_sock *req) |
1da177e4 | 1297 | { |
2e6599cb ACM |
1298 | if (inet_rsk(req)->opt) |
1299 | kfree(inet_rsk(req)->opt); | |
1da177e4 LT |
1300 | } |
1301 | ||
1302 | static inline void syn_flood_warning(struct sk_buff *skb) | |
1303 | { | |
1304 | static unsigned long warntime; | |
1305 | ||
1306 | if (time_after(jiffies, (warntime + HZ * 60))) { | |
1307 | warntime = jiffies; | |
1308 | printk(KERN_INFO | |
1309 | "possible SYN flooding on port %d. Sending cookies.\n", | |
1310 | ntohs(skb->h.th->dest)); | |
1311 | } | |
1312 | } | |
1313 | ||
1314 | /* | |
60236fdd | 1315 | * Save and compile IPv4 options into the request_sock if needed. |
1da177e4 LT |
1316 | */ |
1317 | static inline struct ip_options *tcp_v4_save_options(struct sock *sk, | |
1318 | struct sk_buff *skb) | |
1319 | { | |
1320 | struct ip_options *opt = &(IPCB(skb)->opt); | |
1321 | struct ip_options *dopt = NULL; | |
1322 | ||
1323 | if (opt && opt->optlen) { | |
1324 | int opt_size = optlength(opt); | |
1325 | dopt = kmalloc(opt_size, GFP_ATOMIC); | |
1326 | if (dopt) { | |
1327 | if (ip_options_echo(dopt, skb)) { | |
1328 | kfree(dopt); | |
1329 | dopt = NULL; | |
1330 | } | |
1331 | } | |
1332 | } | |
1333 | return dopt; | |
1334 | } | |
1335 | ||
60236fdd | 1336 | struct request_sock_ops tcp_request_sock_ops = { |
1da177e4 | 1337 | .family = PF_INET, |
2e6599cb | 1338 | .obj_size = sizeof(struct tcp_request_sock), |
1da177e4 | 1339 | .rtx_syn_ack = tcp_v4_send_synack, |
60236fdd ACM |
1340 | .send_ack = tcp_v4_reqsk_send_ack, |
1341 | .destructor = tcp_v4_reqsk_destructor, | |
1da177e4 LT |
1342 | .send_reset = tcp_v4_send_reset, |
1343 | }; | |
1344 | ||
1345 | int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) | |
1346 | { | |
2e6599cb | 1347 | struct inet_request_sock *ireq; |
1da177e4 | 1348 | struct tcp_options_received tmp_opt; |
60236fdd | 1349 | struct request_sock *req; |
1da177e4 LT |
1350 | __u32 saddr = skb->nh.iph->saddr; |
1351 | __u32 daddr = skb->nh.iph->daddr; | |
1352 | __u32 isn = TCP_SKB_CB(skb)->when; | |
1353 | struct dst_entry *dst = NULL; | |
1354 | #ifdef CONFIG_SYN_COOKIES | |
1355 | int want_cookie = 0; | |
1356 | #else | |
1357 | #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */ | |
1358 | #endif | |
1359 | ||
1360 | /* Never answer to SYNs send to broadcast or multicast */ | |
1361 | if (((struct rtable *)skb->dst)->rt_flags & | |
1362 | (RTCF_BROADCAST | RTCF_MULTICAST)) | |
1363 | goto drop; | |
1364 | ||
1365 | /* TW buckets are converted to open requests without | |
1366 | * limitations, they conserve resources and peer is | |
1367 | * evidently real one. | |
1368 | */ | |
1369 | if (tcp_synq_is_full(sk) && !isn) { | |
1370 | #ifdef CONFIG_SYN_COOKIES | |
1371 | if (sysctl_tcp_syncookies) { | |
1372 | want_cookie = 1; | |
1373 | } else | |
1374 | #endif | |
1375 | goto drop; | |
1376 | } | |
1377 | ||
1378 | /* Accept backlog is full. If we have already queued enough | |
1379 | * of warm entries in syn queue, drop request. It is better than | |
1380 | * clogging syn queue with openreqs with exponentially increasing | |
1381 | * timeout. | |
1382 | */ | |
1383 | if (sk_acceptq_is_full(sk) && tcp_synq_young(sk) > 1) | |
1384 | goto drop; | |
1385 | ||
60236fdd | 1386 | req = reqsk_alloc(&tcp_request_sock_ops); |
1da177e4 LT |
1387 | if (!req) |
1388 | goto drop; | |
1389 | ||
1390 | tcp_clear_options(&tmp_opt); | |
1391 | tmp_opt.mss_clamp = 536; | |
1392 | tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss; | |
1393 | ||
1394 | tcp_parse_options(skb, &tmp_opt, 0); | |
1395 | ||
1396 | if (want_cookie) { | |
1397 | tcp_clear_options(&tmp_opt); | |
1398 | tmp_opt.saw_tstamp = 0; | |
1399 | } | |
1400 | ||
1401 | if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) { | |
1402 | /* Some OSes (unknown ones, but I see them on web server, which | |
1403 | * contains information interesting only for windows' | |
1404 | * users) do not send their stamp in SYN. It is easy case. | |
1405 | * We simply do not advertise TS support. | |
1406 | */ | |
1407 | tmp_opt.saw_tstamp = 0; | |
1408 | tmp_opt.tstamp_ok = 0; | |
1409 | } | |
1410 | tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; | |
1411 | ||
1412 | tcp_openreq_init(req, &tmp_opt, skb); | |
1413 | ||
2e6599cb ACM |
1414 | ireq = inet_rsk(req); |
1415 | ireq->loc_addr = daddr; | |
1416 | ireq->rmt_addr = saddr; | |
1417 | ireq->opt = tcp_v4_save_options(sk, skb); | |
1da177e4 LT |
1418 | if (!want_cookie) |
1419 | TCP_ECN_create_request(req, skb->h.th); | |
1420 | ||
1421 | if (want_cookie) { | |
1422 | #ifdef CONFIG_SYN_COOKIES | |
1423 | syn_flood_warning(skb); | |
1424 | #endif | |
1425 | isn = cookie_v4_init_sequence(sk, skb, &req->mss); | |
1426 | } else if (!isn) { | |
1427 | struct inet_peer *peer = NULL; | |
1428 | ||
1429 | /* VJ's idea. We save last timestamp seen | |
1430 | * from the destination in peer table, when entering | |
1431 | * state TIME-WAIT, and check against it before | |
1432 | * accepting new connection request. | |
1433 | * | |
1434 | * If "isn" is not zero, this request hit alive | |
1435 | * timewait bucket, so that all the necessary checks | |
1436 | * are made in the function processing timewait state. | |
1437 | */ | |
1438 | if (tmp_opt.saw_tstamp && | |
1439 | sysctl_tcp_tw_recycle && | |
1440 | (dst = tcp_v4_route_req(sk, req)) != NULL && | |
1441 | (peer = rt_get_peer((struct rtable *)dst)) != NULL && | |
1442 | peer->v4daddr == saddr) { | |
1443 | if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL && | |
1444 | (s32)(peer->tcp_ts - req->ts_recent) > | |
1445 | TCP_PAWS_WINDOW) { | |
1446 | NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED); | |
1447 | dst_release(dst); | |
1448 | goto drop_and_free; | |
1449 | } | |
1450 | } | |
1451 | /* Kill the following clause, if you dislike this way. */ | |
1452 | else if (!sysctl_tcp_syncookies && | |
1453 | (sysctl_max_syn_backlog - tcp_synq_len(sk) < | |
1454 | (sysctl_max_syn_backlog >> 2)) && | |
1455 | (!peer || !peer->tcp_ts_stamp) && | |
1456 | (!dst || !dst_metric(dst, RTAX_RTT))) { | |
1457 | /* Without syncookies last quarter of | |
1458 | * backlog is filled with destinations, | |
1459 | * proven to be alive. | |
1460 | * It means that we continue to communicate | |
1461 | * to destinations, already remembered | |
1462 | * to the moment of synflood. | |
1463 | */ | |
ca933452 HO |
1464 | LIMIT_NETDEBUG(printk(KERN_DEBUG "TCP: drop open " |
1465 | "request from %u.%u." | |
1466 | "%u.%u/%u\n", | |
1467 | NIPQUAD(saddr), | |
1468 | ntohs(skb->h.th->source))); | |
1da177e4 LT |
1469 | dst_release(dst); |
1470 | goto drop_and_free; | |
1471 | } | |
1472 | ||
1473 | isn = tcp_v4_init_sequence(sk, skb); | |
1474 | } | |
2e6599cb | 1475 | tcp_rsk(req)->snt_isn = isn; |
1da177e4 LT |
1476 | |
1477 | if (tcp_v4_send_synack(sk, req, dst)) | |
1478 | goto drop_and_free; | |
1479 | ||
1480 | if (want_cookie) { | |
60236fdd | 1481 | reqsk_free(req); |
1da177e4 LT |
1482 | } else { |
1483 | tcp_v4_synq_add(sk, req); | |
1484 | } | |
1485 | return 0; | |
1486 | ||
1487 | drop_and_free: | |
60236fdd | 1488 | reqsk_free(req); |
1da177e4 LT |
1489 | drop: |
1490 | TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); | |
1491 | return 0; | |
1492 | } | |
1493 | ||
1494 | ||
1495 | /* | |
1496 | * The three way handshake has completed - we got a valid synack - | |
1497 | * now create the new socket. | |
1498 | */ | |
1499 | struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, | |
60236fdd | 1500 | struct request_sock *req, |
1da177e4 LT |
1501 | struct dst_entry *dst) |
1502 | { | |
2e6599cb | 1503 | struct inet_request_sock *ireq; |
1da177e4 LT |
1504 | struct inet_sock *newinet; |
1505 | struct tcp_sock *newtp; | |
1506 | struct sock *newsk; | |
1507 | ||
1508 | if (sk_acceptq_is_full(sk)) | |
1509 | goto exit_overflow; | |
1510 | ||
1511 | if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL) | |
1512 | goto exit; | |
1513 | ||
1514 | newsk = tcp_create_openreq_child(sk, req, skb); | |
1515 | if (!newsk) | |
1516 | goto exit; | |
1517 | ||
6cbb0df7 | 1518 | sk_setup_caps(newsk, dst); |
1da177e4 LT |
1519 | |
1520 | newtp = tcp_sk(newsk); | |
1521 | newinet = inet_sk(newsk); | |
2e6599cb ACM |
1522 | ireq = inet_rsk(req); |
1523 | newinet->daddr = ireq->rmt_addr; | |
1524 | newinet->rcv_saddr = ireq->loc_addr; | |
1525 | newinet->saddr = ireq->loc_addr; | |
1526 | newinet->opt = ireq->opt; | |
1527 | ireq->opt = NULL; | |
1da177e4 LT |
1528 | newinet->mc_index = tcp_v4_iif(skb); |
1529 | newinet->mc_ttl = skb->nh.iph->ttl; | |
1530 | newtp->ext_header_len = 0; | |
1531 | if (newinet->opt) | |
1532 | newtp->ext_header_len = newinet->opt->optlen; | |
1533 | newinet->id = newtp->write_seq ^ jiffies; | |
1534 | ||
1535 | tcp_sync_mss(newsk, dst_mtu(dst)); | |
1536 | newtp->advmss = dst_metric(dst, RTAX_ADVMSS); | |
1537 | tcp_initialize_rcv_mss(newsk); | |
1538 | ||
1539 | __tcp_v4_hash(newsk, 0); | |
1540 | __tcp_inherit_port(sk, newsk); | |
1541 | ||
1542 | return newsk; | |
1543 | ||
1544 | exit_overflow: | |
1545 | NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS); | |
1546 | exit: | |
1547 | NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS); | |
1548 | dst_release(dst); | |
1549 | return NULL; | |
1550 | } | |
1551 | ||
1552 | static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) | |
1553 | { | |
1554 | struct tcphdr *th = skb->h.th; | |
1555 | struct iphdr *iph = skb->nh.iph; | |
1556 | struct tcp_sock *tp = tcp_sk(sk); | |
1557 | struct sock *nsk; | |
60236fdd | 1558 | struct request_sock **prev; |
1da177e4 | 1559 | /* Find possible connection requests. */ |
60236fdd | 1560 | struct request_sock *req = tcp_v4_search_req(tp, &prev, th->source, |
1da177e4 LT |
1561 | iph->saddr, iph->daddr); |
1562 | if (req) | |
1563 | return tcp_check_req(sk, skb, req, prev); | |
1564 | ||
1565 | nsk = __tcp_v4_lookup_established(skb->nh.iph->saddr, | |
1566 | th->source, | |
1567 | skb->nh.iph->daddr, | |
1568 | ntohs(th->dest), | |
1569 | tcp_v4_iif(skb)); | |
1570 | ||
1571 | if (nsk) { | |
1572 | if (nsk->sk_state != TCP_TIME_WAIT) { | |
1573 | bh_lock_sock(nsk); | |
1574 | return nsk; | |
1575 | } | |
1576 | tcp_tw_put((struct tcp_tw_bucket *)nsk); | |
1577 | return NULL; | |
1578 | } | |
1579 | ||
1580 | #ifdef CONFIG_SYN_COOKIES | |
1581 | if (!th->rst && !th->syn && th->ack) | |
1582 | sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt)); | |
1583 | #endif | |
1584 | return sk; | |
1585 | } | |
1586 | ||
1587 | static int tcp_v4_checksum_init(struct sk_buff *skb) | |
1588 | { | |
1589 | if (skb->ip_summed == CHECKSUM_HW) { | |
1590 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
1591 | if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr, | |
1592 | skb->nh.iph->daddr, skb->csum)) | |
1593 | return 0; | |
1594 | ||
ca933452 | 1595 | LIMIT_NETDEBUG(printk(KERN_DEBUG "hw tcp v4 csum failed\n")); |
1da177e4 LT |
1596 | skb->ip_summed = CHECKSUM_NONE; |
1597 | } | |
1598 | if (skb->len <= 76) { | |
1599 | if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr, | |
1600 | skb->nh.iph->daddr, | |
1601 | skb_checksum(skb, 0, skb->len, 0))) | |
1602 | return -1; | |
1603 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
1604 | } else { | |
1605 | skb->csum = ~tcp_v4_check(skb->h.th, skb->len, | |
1606 | skb->nh.iph->saddr, | |
1607 | skb->nh.iph->daddr, 0); | |
1608 | } | |
1609 | return 0; | |
1610 | } | |
1611 | ||
1612 | ||
1613 | /* The socket must have it's spinlock held when we get | |
1614 | * here. | |
1615 | * | |
1616 | * We have a potential double-lock case here, so even when | |
1617 | * doing backlog processing we use the BH locking scheme. | |
1618 | * This is because we cannot sleep with the original spinlock | |
1619 | * held. | |
1620 | */ | |
1621 | int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) | |
1622 | { | |
1623 | if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ | |
1624 | TCP_CHECK_TIMER(sk); | |
1625 | if (tcp_rcv_established(sk, skb, skb->h.th, skb->len)) | |
1626 | goto reset; | |
1627 | TCP_CHECK_TIMER(sk); | |
1628 | return 0; | |
1629 | } | |
1630 | ||
1631 | if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb)) | |
1632 | goto csum_err; | |
1633 | ||
1634 | if (sk->sk_state == TCP_LISTEN) { | |
1635 | struct sock *nsk = tcp_v4_hnd_req(sk, skb); | |
1636 | if (!nsk) | |
1637 | goto discard; | |
1638 | ||
1639 | if (nsk != sk) { | |
1640 | if (tcp_child_process(sk, nsk, skb)) | |
1641 | goto reset; | |
1642 | return 0; | |
1643 | } | |
1644 | } | |
1645 | ||
1646 | TCP_CHECK_TIMER(sk); | |
1647 | if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len)) | |
1648 | goto reset; | |
1649 | TCP_CHECK_TIMER(sk); | |
1650 | return 0; | |
1651 | ||
1652 | reset: | |
1653 | tcp_v4_send_reset(skb); | |
1654 | discard: | |
1655 | kfree_skb(skb); | |
1656 | /* Be careful here. If this function gets more complicated and | |
1657 | * gcc suffers from register pressure on the x86, sk (in %ebx) | |
1658 | * might be destroyed here. This current version compiles correctly, | |
1659 | * but you have been warned. | |
1660 | */ | |
1661 | return 0; | |
1662 | ||
1663 | csum_err: | |
1664 | TCP_INC_STATS_BH(TCP_MIB_INERRS); | |
1665 | goto discard; | |
1666 | } | |
1667 | ||
1668 | /* | |
1669 | * From tcp_input.c | |
1670 | */ | |
1671 | ||
1672 | int tcp_v4_rcv(struct sk_buff *skb) | |
1673 | { | |
1674 | struct tcphdr *th; | |
1675 | struct sock *sk; | |
1676 | int ret; | |
1677 | ||
1678 | if (skb->pkt_type != PACKET_HOST) | |
1679 | goto discard_it; | |
1680 | ||
1681 | /* Count it even if it's bad */ | |
1682 | TCP_INC_STATS_BH(TCP_MIB_INSEGS); | |
1683 | ||
1684 | if (!pskb_may_pull(skb, sizeof(struct tcphdr))) | |
1685 | goto discard_it; | |
1686 | ||
1687 | th = skb->h.th; | |
1688 | ||
1689 | if (th->doff < sizeof(struct tcphdr) / 4) | |
1690 | goto bad_packet; | |
1691 | if (!pskb_may_pull(skb, th->doff * 4)) | |
1692 | goto discard_it; | |
1693 | ||
1694 | /* An explanation is required here, I think. | |
1695 | * Packet length and doff are validated by header prediction, | |
1696 | * provided case of th->doff==0 is elimineted. | |
1697 | * So, we defer the checks. */ | |
1698 | if ((skb->ip_summed != CHECKSUM_UNNECESSARY && | |
1699 | tcp_v4_checksum_init(skb) < 0)) | |
1700 | goto bad_packet; | |
1701 | ||
1702 | th = skb->h.th; | |
1703 | TCP_SKB_CB(skb)->seq = ntohl(th->seq); | |
1704 | TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + | |
1705 | skb->len - th->doff * 4); | |
1706 | TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); | |
1707 | TCP_SKB_CB(skb)->when = 0; | |
1708 | TCP_SKB_CB(skb)->flags = skb->nh.iph->tos; | |
1709 | TCP_SKB_CB(skb)->sacked = 0; | |
1710 | ||
1711 | sk = __tcp_v4_lookup(skb->nh.iph->saddr, th->source, | |
1712 | skb->nh.iph->daddr, ntohs(th->dest), | |
1713 | tcp_v4_iif(skb)); | |
1714 | ||
1715 | if (!sk) | |
1716 | goto no_tcp_socket; | |
1717 | ||
1718 | process: | |
1719 | if (sk->sk_state == TCP_TIME_WAIT) | |
1720 | goto do_time_wait; | |
1721 | ||
1722 | if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) | |
1723 | goto discard_and_relse; | |
1724 | ||
1725 | if (sk_filter(sk, skb, 0)) | |
1726 | goto discard_and_relse; | |
1727 | ||
1728 | skb->dev = NULL; | |
1729 | ||
1730 | bh_lock_sock(sk); | |
1731 | ret = 0; | |
1732 | if (!sock_owned_by_user(sk)) { | |
1733 | if (!tcp_prequeue(sk, skb)) | |
1734 | ret = tcp_v4_do_rcv(sk, skb); | |
1735 | } else | |
1736 | sk_add_backlog(sk, skb); | |
1737 | bh_unlock_sock(sk); | |
1738 | ||
1739 | sock_put(sk); | |
1740 | ||
1741 | return ret; | |
1742 | ||
1743 | no_tcp_socket: | |
1744 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) | |
1745 | goto discard_it; | |
1746 | ||
1747 | if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { | |
1748 | bad_packet: | |
1749 | TCP_INC_STATS_BH(TCP_MIB_INERRS); | |
1750 | } else { | |
1751 | tcp_v4_send_reset(skb); | |
1752 | } | |
1753 | ||
1754 | discard_it: | |
1755 | /* Discard frame. */ | |
1756 | kfree_skb(skb); | |
1757 | return 0; | |
1758 | ||
1759 | discard_and_relse: | |
1760 | sock_put(sk); | |
1761 | goto discard_it; | |
1762 | ||
1763 | do_time_wait: | |
1764 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { | |
1765 | tcp_tw_put((struct tcp_tw_bucket *) sk); | |
1766 | goto discard_it; | |
1767 | } | |
1768 | ||
1769 | if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { | |
1770 | TCP_INC_STATS_BH(TCP_MIB_INERRS); | |
1771 | tcp_tw_put((struct tcp_tw_bucket *) sk); | |
1772 | goto discard_it; | |
1773 | } | |
1774 | switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk, | |
1775 | skb, th, skb->len)) { | |
1776 | case TCP_TW_SYN: { | |
1777 | struct sock *sk2 = tcp_v4_lookup_listener(skb->nh.iph->daddr, | |
1778 | ntohs(th->dest), | |
1779 | tcp_v4_iif(skb)); | |
1780 | if (sk2) { | |
1781 | tcp_tw_deschedule((struct tcp_tw_bucket *)sk); | |
1782 | tcp_tw_put((struct tcp_tw_bucket *)sk); | |
1783 | sk = sk2; | |
1784 | goto process; | |
1785 | } | |
1786 | /* Fall through to ACK */ | |
1787 | } | |
1788 | case TCP_TW_ACK: | |
1789 | tcp_v4_timewait_ack(sk, skb); | |
1790 | break; | |
1791 | case TCP_TW_RST: | |
1792 | goto no_tcp_socket; | |
1793 | case TCP_TW_SUCCESS:; | |
1794 | } | |
1795 | goto discard_it; | |
1796 | } | |
1797 | ||
1da177e4 LT |
1798 | static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr) |
1799 | { | |
1800 | struct sockaddr_in *sin = (struct sockaddr_in *) uaddr; | |
1801 | struct inet_sock *inet = inet_sk(sk); | |
1802 | ||
1803 | sin->sin_family = AF_INET; | |
1804 | sin->sin_addr.s_addr = inet->daddr; | |
1805 | sin->sin_port = inet->dport; | |
1806 | } | |
1807 | ||
1808 | /* VJ's idea. Save last timestamp seen from this destination | |
1809 | * and hold it at least for normal timewait interval to use for duplicate | |
1810 | * segment detection in subsequent connections, before they enter synchronized | |
1811 | * state. | |
1812 | */ | |
1813 | ||
1814 | int tcp_v4_remember_stamp(struct sock *sk) | |
1815 | { | |
1816 | struct inet_sock *inet = inet_sk(sk); | |
1817 | struct tcp_sock *tp = tcp_sk(sk); | |
1818 | struct rtable *rt = (struct rtable *)__sk_dst_get(sk); | |
1819 | struct inet_peer *peer = NULL; | |
1820 | int release_it = 0; | |
1821 | ||
1822 | if (!rt || rt->rt_dst != inet->daddr) { | |
1823 | peer = inet_getpeer(inet->daddr, 1); | |
1824 | release_it = 1; | |
1825 | } else { | |
1826 | if (!rt->peer) | |
1827 | rt_bind_peer(rt, 1); | |
1828 | peer = rt->peer; | |
1829 | } | |
1830 | ||
1831 | if (peer) { | |
1832 | if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 || | |
1833 | (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && | |
1834 | peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) { | |
1835 | peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp; | |
1836 | peer->tcp_ts = tp->rx_opt.ts_recent; | |
1837 | } | |
1838 | if (release_it) | |
1839 | inet_putpeer(peer); | |
1840 | return 1; | |
1841 | } | |
1842 | ||
1843 | return 0; | |
1844 | } | |
1845 | ||
1846 | int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw) | |
1847 | { | |
1848 | struct inet_peer *peer = NULL; | |
1849 | ||
1850 | peer = inet_getpeer(tw->tw_daddr, 1); | |
1851 | ||
1852 | if (peer) { | |
1853 | if ((s32)(peer->tcp_ts - tw->tw_ts_recent) <= 0 || | |
1854 | (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && | |
1855 | peer->tcp_ts_stamp <= tw->tw_ts_recent_stamp)) { | |
1856 | peer->tcp_ts_stamp = tw->tw_ts_recent_stamp; | |
1857 | peer->tcp_ts = tw->tw_ts_recent; | |
1858 | } | |
1859 | inet_putpeer(peer); | |
1860 | return 1; | |
1861 | } | |
1862 | ||
1863 | return 0; | |
1864 | } | |
1865 | ||
1866 | struct tcp_func ipv4_specific = { | |
1867 | .queue_xmit = ip_queue_xmit, | |
1868 | .send_check = tcp_v4_send_check, | |
32519f11 | 1869 | .rebuild_header = inet_sk_rebuild_header, |
1da177e4 LT |
1870 | .conn_request = tcp_v4_conn_request, |
1871 | .syn_recv_sock = tcp_v4_syn_recv_sock, | |
1872 | .remember_stamp = tcp_v4_remember_stamp, | |
1873 | .net_header_len = sizeof(struct iphdr), | |
1874 | .setsockopt = ip_setsockopt, | |
1875 | .getsockopt = ip_getsockopt, | |
1876 | .addr2sockaddr = v4_addr2sockaddr, | |
1877 | .sockaddr_len = sizeof(struct sockaddr_in), | |
1878 | }; | |
1879 | ||
1880 | /* NOTE: A lot of things set to zero explicitly by call to | |
1881 | * sk_alloc() so need not be done here. | |
1882 | */ | |
1883 | static int tcp_v4_init_sock(struct sock *sk) | |
1884 | { | |
1885 | struct tcp_sock *tp = tcp_sk(sk); | |
1886 | ||
1887 | skb_queue_head_init(&tp->out_of_order_queue); | |
1888 | tcp_init_xmit_timers(sk); | |
1889 | tcp_prequeue_init(tp); | |
1890 | ||
1891 | tp->rto = TCP_TIMEOUT_INIT; | |
1892 | tp->mdev = TCP_TIMEOUT_INIT; | |
1893 | ||
1894 | /* So many TCP implementations out there (incorrectly) count the | |
1895 | * initial SYN frame in their delayed-ACK and congestion control | |
1896 | * algorithms that we must have the following bandaid to talk | |
1897 | * efficiently to them. -DaveM | |
1898 | */ | |
1899 | tp->snd_cwnd = 2; | |
1900 | ||
1901 | /* See draft-stevens-tcpca-spec-01 for discussion of the | |
1902 | * initialization of these values. | |
1903 | */ | |
1904 | tp->snd_ssthresh = 0x7fffffff; /* Infinity */ | |
1905 | tp->snd_cwnd_clamp = ~0; | |
c1b4a7e6 | 1906 | tp->mss_cache = 536; |
1da177e4 LT |
1907 | |
1908 | tp->reordering = sysctl_tcp_reordering; | |
5f8ef48d | 1909 | tp->ca_ops = &tcp_init_congestion_ops; |
1da177e4 LT |
1910 | |
1911 | sk->sk_state = TCP_CLOSE; | |
1912 | ||
1913 | sk->sk_write_space = sk_stream_write_space; | |
1914 | sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); | |
1915 | ||
1916 | tp->af_specific = &ipv4_specific; | |
1917 | ||
1918 | sk->sk_sndbuf = sysctl_tcp_wmem[1]; | |
1919 | sk->sk_rcvbuf = sysctl_tcp_rmem[1]; | |
1920 | ||
1921 | atomic_inc(&tcp_sockets_allocated); | |
1922 | ||
1923 | return 0; | |
1924 | } | |
1925 | ||
1926 | int tcp_v4_destroy_sock(struct sock *sk) | |
1927 | { | |
1928 | struct tcp_sock *tp = tcp_sk(sk); | |
1929 | ||
1930 | tcp_clear_xmit_timers(sk); | |
1931 | ||
317a76f9 SH |
1932 | tcp_cleanup_congestion_control(tp); |
1933 | ||
1da177e4 LT |
1934 | /* Cleanup up the write buffer. */ |
1935 | sk_stream_writequeue_purge(sk); | |
1936 | ||
1937 | /* Cleans up our, hopefully empty, out_of_order_queue. */ | |
1938 | __skb_queue_purge(&tp->out_of_order_queue); | |
1939 | ||
1940 | /* Clean prequeue, it must be empty really */ | |
1941 | __skb_queue_purge(&tp->ucopy.prequeue); | |
1942 | ||
1943 | /* Clean up a referenced TCP bind bucket. */ | |
a55ebcc4 | 1944 | if (inet_sk(sk)->bind_hash) |
1da177e4 LT |
1945 | tcp_put_port(sk); |
1946 | ||
1947 | /* | |
1948 | * If sendmsg cached page exists, toss it. | |
1949 | */ | |
1950 | if (sk->sk_sndmsg_page) { | |
1951 | __free_page(sk->sk_sndmsg_page); | |
1952 | sk->sk_sndmsg_page = NULL; | |
1953 | } | |
1954 | ||
1955 | atomic_dec(&tcp_sockets_allocated); | |
1956 | ||
1957 | return 0; | |
1958 | } | |
1959 | ||
1960 | EXPORT_SYMBOL(tcp_v4_destroy_sock); | |
1961 | ||
1962 | #ifdef CONFIG_PROC_FS | |
1963 | /* Proc filesystem TCP sock list dumping. */ | |
1964 | ||
1965 | static inline struct tcp_tw_bucket *tw_head(struct hlist_head *head) | |
1966 | { | |
1967 | return hlist_empty(head) ? NULL : | |
1968 | list_entry(head->first, struct tcp_tw_bucket, tw_node); | |
1969 | } | |
1970 | ||
1971 | static inline struct tcp_tw_bucket *tw_next(struct tcp_tw_bucket *tw) | |
1972 | { | |
1973 | return tw->tw_node.next ? | |
1974 | hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL; | |
1975 | } | |
1976 | ||
1977 | static void *listening_get_next(struct seq_file *seq, void *cur) | |
1978 | { | |
1979 | struct tcp_sock *tp; | |
1980 | struct hlist_node *node; | |
1981 | struct sock *sk = cur; | |
1982 | struct tcp_iter_state* st = seq->private; | |
1983 | ||
1984 | if (!sk) { | |
1985 | st->bucket = 0; | |
1986 | sk = sk_head(&tcp_listening_hash[0]); | |
1987 | goto get_sk; | |
1988 | } | |
1989 | ||
1990 | ++st->num; | |
1991 | ||
1992 | if (st->state == TCP_SEQ_STATE_OPENREQ) { | |
60236fdd | 1993 | struct request_sock *req = cur; |
1da177e4 LT |
1994 | |
1995 | tp = tcp_sk(st->syn_wait_sk); | |
1996 | req = req->dl_next; | |
1997 | while (1) { | |
1998 | while (req) { | |
60236fdd | 1999 | if (req->rsk_ops->family == st->family) { |
1da177e4 LT |
2000 | cur = req; |
2001 | goto out; | |
2002 | } | |
2003 | req = req->dl_next; | |
2004 | } | |
2005 | if (++st->sbucket >= TCP_SYNQ_HSIZE) | |
2006 | break; | |
2007 | get_req: | |
0e87506f | 2008 | req = tp->accept_queue.listen_opt->syn_table[st->sbucket]; |
1da177e4 LT |
2009 | } |
2010 | sk = sk_next(st->syn_wait_sk); | |
2011 | st->state = TCP_SEQ_STATE_LISTENING; | |
0e87506f | 2012 | read_unlock_bh(&tp->accept_queue.syn_wait_lock); |
1da177e4 LT |
2013 | } else { |
2014 | tp = tcp_sk(sk); | |
0e87506f ACM |
2015 | read_lock_bh(&tp->accept_queue.syn_wait_lock); |
2016 | if (reqsk_queue_len(&tp->accept_queue)) | |
1da177e4 | 2017 | goto start_req; |
0e87506f | 2018 | read_unlock_bh(&tp->accept_queue.syn_wait_lock); |
1da177e4 LT |
2019 | sk = sk_next(sk); |
2020 | } | |
2021 | get_sk: | |
2022 | sk_for_each_from(sk, node) { | |
2023 | if (sk->sk_family == st->family) { | |
2024 | cur = sk; | |
2025 | goto out; | |
2026 | } | |
2027 | tp = tcp_sk(sk); | |
0e87506f ACM |
2028 | read_lock_bh(&tp->accept_queue.syn_wait_lock); |
2029 | if (reqsk_queue_len(&tp->accept_queue)) { | |
1da177e4 LT |
2030 | start_req: |
2031 | st->uid = sock_i_uid(sk); | |
2032 | st->syn_wait_sk = sk; | |
2033 | st->state = TCP_SEQ_STATE_OPENREQ; | |
2034 | st->sbucket = 0; | |
2035 | goto get_req; | |
2036 | } | |
0e87506f | 2037 | read_unlock_bh(&tp->accept_queue.syn_wait_lock); |
1da177e4 | 2038 | } |
0f7ff927 | 2039 | if (++st->bucket < INET_LHTABLE_SIZE) { |
1da177e4 LT |
2040 | sk = sk_head(&tcp_listening_hash[st->bucket]); |
2041 | goto get_sk; | |
2042 | } | |
2043 | cur = NULL; | |
2044 | out: | |
2045 | return cur; | |
2046 | } | |
2047 | ||
2048 | static void *listening_get_idx(struct seq_file *seq, loff_t *pos) | |
2049 | { | |
2050 | void *rc = listening_get_next(seq, NULL); | |
2051 | ||
2052 | while (rc && *pos) { | |
2053 | rc = listening_get_next(seq, rc); | |
2054 | --*pos; | |
2055 | } | |
2056 | return rc; | |
2057 | } | |
2058 | ||
2059 | static void *established_get_first(struct seq_file *seq) | |
2060 | { | |
2061 | struct tcp_iter_state* st = seq->private; | |
2062 | void *rc = NULL; | |
2063 | ||
2064 | for (st->bucket = 0; st->bucket < tcp_ehash_size; ++st->bucket) { | |
2065 | struct sock *sk; | |
2066 | struct hlist_node *node; | |
2067 | struct tcp_tw_bucket *tw; | |
2068 | ||
2069 | /* We can reschedule _before_ having picked the target: */ | |
2070 | cond_resched_softirq(); | |
2071 | ||
2072 | read_lock(&tcp_ehash[st->bucket].lock); | |
2073 | sk_for_each(sk, node, &tcp_ehash[st->bucket].chain) { | |
2074 | if (sk->sk_family != st->family) { | |
2075 | continue; | |
2076 | } | |
2077 | rc = sk; | |
2078 | goto out; | |
2079 | } | |
2080 | st->state = TCP_SEQ_STATE_TIME_WAIT; | |
2081 | tw_for_each(tw, node, | |
2082 | &tcp_ehash[st->bucket + tcp_ehash_size].chain) { | |
2083 | if (tw->tw_family != st->family) { | |
2084 | continue; | |
2085 | } | |
2086 | rc = tw; | |
2087 | goto out; | |
2088 | } | |
2089 | read_unlock(&tcp_ehash[st->bucket].lock); | |
2090 | st->state = TCP_SEQ_STATE_ESTABLISHED; | |
2091 | } | |
2092 | out: | |
2093 | return rc; | |
2094 | } | |
2095 | ||
2096 | static void *established_get_next(struct seq_file *seq, void *cur) | |
2097 | { | |
2098 | struct sock *sk = cur; | |
2099 | struct tcp_tw_bucket *tw; | |
2100 | struct hlist_node *node; | |
2101 | struct tcp_iter_state* st = seq->private; | |
2102 | ||
2103 | ++st->num; | |
2104 | ||
2105 | if (st->state == TCP_SEQ_STATE_TIME_WAIT) { | |
2106 | tw = cur; | |
2107 | tw = tw_next(tw); | |
2108 | get_tw: | |
2109 | while (tw && tw->tw_family != st->family) { | |
2110 | tw = tw_next(tw); | |
2111 | } | |
2112 | if (tw) { | |
2113 | cur = tw; | |
2114 | goto out; | |
2115 | } | |
2116 | read_unlock(&tcp_ehash[st->bucket].lock); | |
2117 | st->state = TCP_SEQ_STATE_ESTABLISHED; | |
2118 | ||
2119 | /* We can reschedule between buckets: */ | |
2120 | cond_resched_softirq(); | |
2121 | ||
2122 | if (++st->bucket < tcp_ehash_size) { | |
2123 | read_lock(&tcp_ehash[st->bucket].lock); | |
2124 | sk = sk_head(&tcp_ehash[st->bucket].chain); | |
2125 | } else { | |
2126 | cur = NULL; | |
2127 | goto out; | |
2128 | } | |
2129 | } else | |
2130 | sk = sk_next(sk); | |
2131 | ||
2132 | sk_for_each_from(sk, node) { | |
2133 | if (sk->sk_family == st->family) | |
2134 | goto found; | |
2135 | } | |
2136 | ||
2137 | st->state = TCP_SEQ_STATE_TIME_WAIT; | |
2138 | tw = tw_head(&tcp_ehash[st->bucket + tcp_ehash_size].chain); | |
2139 | goto get_tw; | |
2140 | found: | |
2141 | cur = sk; | |
2142 | out: | |
2143 | return cur; | |
2144 | } | |
2145 | ||
2146 | static void *established_get_idx(struct seq_file *seq, loff_t pos) | |
2147 | { | |
2148 | void *rc = established_get_first(seq); | |
2149 | ||
2150 | while (rc && pos) { | |
2151 | rc = established_get_next(seq, rc); | |
2152 | --pos; | |
2153 | } | |
2154 | return rc; | |
2155 | } | |
2156 | ||
2157 | static void *tcp_get_idx(struct seq_file *seq, loff_t pos) | |
2158 | { | |
2159 | void *rc; | |
2160 | struct tcp_iter_state* st = seq->private; | |
2161 | ||
2162 | tcp_listen_lock(); | |
2163 | st->state = TCP_SEQ_STATE_LISTENING; | |
2164 | rc = listening_get_idx(seq, &pos); | |
2165 | ||
2166 | if (!rc) { | |
2167 | tcp_listen_unlock(); | |
2168 | local_bh_disable(); | |
2169 | st->state = TCP_SEQ_STATE_ESTABLISHED; | |
2170 | rc = established_get_idx(seq, pos); | |
2171 | } | |
2172 | ||
2173 | return rc; | |
2174 | } | |
2175 | ||
2176 | static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) | |
2177 | { | |
2178 | struct tcp_iter_state* st = seq->private; | |
2179 | st->state = TCP_SEQ_STATE_LISTENING; | |
2180 | st->num = 0; | |
2181 | return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; | |
2182 | } | |
2183 | ||
2184 | static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
2185 | { | |
2186 | void *rc = NULL; | |
2187 | struct tcp_iter_state* st; | |
2188 | ||
2189 | if (v == SEQ_START_TOKEN) { | |
2190 | rc = tcp_get_idx(seq, 0); | |
2191 | goto out; | |
2192 | } | |
2193 | st = seq->private; | |
2194 | ||
2195 | switch (st->state) { | |
2196 | case TCP_SEQ_STATE_OPENREQ: | |
2197 | case TCP_SEQ_STATE_LISTENING: | |
2198 | rc = listening_get_next(seq, v); | |
2199 | if (!rc) { | |
2200 | tcp_listen_unlock(); | |
2201 | local_bh_disable(); | |
2202 | st->state = TCP_SEQ_STATE_ESTABLISHED; | |
2203 | rc = established_get_first(seq); | |
2204 | } | |
2205 | break; | |
2206 | case TCP_SEQ_STATE_ESTABLISHED: | |
2207 | case TCP_SEQ_STATE_TIME_WAIT: | |
2208 | rc = established_get_next(seq, v); | |
2209 | break; | |
2210 | } | |
2211 | out: | |
2212 | ++*pos; | |
2213 | return rc; | |
2214 | } | |
2215 | ||
2216 | static void tcp_seq_stop(struct seq_file *seq, void *v) | |
2217 | { | |
2218 | struct tcp_iter_state* st = seq->private; | |
2219 | ||
2220 | switch (st->state) { | |
2221 | case TCP_SEQ_STATE_OPENREQ: | |
2222 | if (v) { | |
2223 | struct tcp_sock *tp = tcp_sk(st->syn_wait_sk); | |
0e87506f | 2224 | read_unlock_bh(&tp->accept_queue.syn_wait_lock); |
1da177e4 LT |
2225 | } |
2226 | case TCP_SEQ_STATE_LISTENING: | |
2227 | if (v != SEQ_START_TOKEN) | |
2228 | tcp_listen_unlock(); | |
2229 | break; | |
2230 | case TCP_SEQ_STATE_TIME_WAIT: | |
2231 | case TCP_SEQ_STATE_ESTABLISHED: | |
2232 | if (v) | |
2233 | read_unlock(&tcp_ehash[st->bucket].lock); | |
2234 | local_bh_enable(); | |
2235 | break; | |
2236 | } | |
2237 | } | |
2238 | ||
2239 | static int tcp_seq_open(struct inode *inode, struct file *file) | |
2240 | { | |
2241 | struct tcp_seq_afinfo *afinfo = PDE(inode)->data; | |
2242 | struct seq_file *seq; | |
2243 | struct tcp_iter_state *s; | |
2244 | int rc; | |
2245 | ||
2246 | if (unlikely(afinfo == NULL)) | |
2247 | return -EINVAL; | |
2248 | ||
2249 | s = kmalloc(sizeof(*s), GFP_KERNEL); | |
2250 | if (!s) | |
2251 | return -ENOMEM; | |
2252 | memset(s, 0, sizeof(*s)); | |
2253 | s->family = afinfo->family; | |
2254 | s->seq_ops.start = tcp_seq_start; | |
2255 | s->seq_ops.next = tcp_seq_next; | |
2256 | s->seq_ops.show = afinfo->seq_show; | |
2257 | s->seq_ops.stop = tcp_seq_stop; | |
2258 | ||
2259 | rc = seq_open(file, &s->seq_ops); | |
2260 | if (rc) | |
2261 | goto out_kfree; | |
2262 | seq = file->private_data; | |
2263 | seq->private = s; | |
2264 | out: | |
2265 | return rc; | |
2266 | out_kfree: | |
2267 | kfree(s); | |
2268 | goto out; | |
2269 | } | |
2270 | ||
2271 | int tcp_proc_register(struct tcp_seq_afinfo *afinfo) | |
2272 | { | |
2273 | int rc = 0; | |
2274 | struct proc_dir_entry *p; | |
2275 | ||
2276 | if (!afinfo) | |
2277 | return -EINVAL; | |
2278 | afinfo->seq_fops->owner = afinfo->owner; | |
2279 | afinfo->seq_fops->open = tcp_seq_open; | |
2280 | afinfo->seq_fops->read = seq_read; | |
2281 | afinfo->seq_fops->llseek = seq_lseek; | |
2282 | afinfo->seq_fops->release = seq_release_private; | |
2283 | ||
2284 | p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops); | |
2285 | if (p) | |
2286 | p->data = afinfo; | |
2287 | else | |
2288 | rc = -ENOMEM; | |
2289 | return rc; | |
2290 | } | |
2291 | ||
2292 | void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo) | |
2293 | { | |
2294 | if (!afinfo) | |
2295 | return; | |
2296 | proc_net_remove(afinfo->name); | |
2297 | memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops)); | |
2298 | } | |
2299 | ||
60236fdd | 2300 | static void get_openreq4(struct sock *sk, struct request_sock *req, |
1da177e4 LT |
2301 | char *tmpbuf, int i, int uid) |
2302 | { | |
2e6599cb | 2303 | const struct inet_request_sock *ireq = inet_rsk(req); |
1da177e4 LT |
2304 | int ttd = req->expires - jiffies; |
2305 | ||
2306 | sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" | |
2307 | " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p", | |
2308 | i, | |
2e6599cb | 2309 | ireq->loc_addr, |
1da177e4 | 2310 | ntohs(inet_sk(sk)->sport), |
2e6599cb ACM |
2311 | ireq->rmt_addr, |
2312 | ntohs(ireq->rmt_port), | |
1da177e4 LT |
2313 | TCP_SYN_RECV, |
2314 | 0, 0, /* could print option size, but that is af dependent. */ | |
2315 | 1, /* timers active (only the expire timer) */ | |
2316 | jiffies_to_clock_t(ttd), | |
2317 | req->retrans, | |
2318 | uid, | |
2319 | 0, /* non standard timer */ | |
2320 | 0, /* open_requests have no inode */ | |
2321 | atomic_read(&sk->sk_refcnt), | |
2322 | req); | |
2323 | } | |
2324 | ||
2325 | static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i) | |
2326 | { | |
2327 | int timer_active; | |
2328 | unsigned long timer_expires; | |
2329 | struct tcp_sock *tp = tcp_sk(sp); | |
2330 | struct inet_sock *inet = inet_sk(sp); | |
2331 | unsigned int dest = inet->daddr; | |
2332 | unsigned int src = inet->rcv_saddr; | |
2333 | __u16 destp = ntohs(inet->dport); | |
2334 | __u16 srcp = ntohs(inet->sport); | |
2335 | ||
2336 | if (tp->pending == TCP_TIME_RETRANS) { | |
2337 | timer_active = 1; | |
2338 | timer_expires = tp->timeout; | |
2339 | } else if (tp->pending == TCP_TIME_PROBE0) { | |
2340 | timer_active = 4; | |
2341 | timer_expires = tp->timeout; | |
2342 | } else if (timer_pending(&sp->sk_timer)) { | |
2343 | timer_active = 2; | |
2344 | timer_expires = sp->sk_timer.expires; | |
2345 | } else { | |
2346 | timer_active = 0; | |
2347 | timer_expires = jiffies; | |
2348 | } | |
2349 | ||
2350 | sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " | |
2351 | "%08X %5d %8d %lu %d %p %u %u %u %u %d", | |
2352 | i, src, srcp, dest, destp, sp->sk_state, | |
2353 | tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq, | |
2354 | timer_active, | |
2355 | jiffies_to_clock_t(timer_expires - jiffies), | |
2356 | tp->retransmits, | |
2357 | sock_i_uid(sp), | |
2358 | tp->probes_out, | |
2359 | sock_i_ino(sp), | |
2360 | atomic_read(&sp->sk_refcnt), sp, | |
2361 | tp->rto, tp->ack.ato, (tp->ack.quick << 1) | tp->ack.pingpong, | |
2362 | tp->snd_cwnd, | |
2363 | tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh); | |
2364 | } | |
2365 | ||
2366 | static void get_timewait4_sock(struct tcp_tw_bucket *tw, char *tmpbuf, int i) | |
2367 | { | |
2368 | unsigned int dest, src; | |
2369 | __u16 destp, srcp; | |
2370 | int ttd = tw->tw_ttd - jiffies; | |
2371 | ||
2372 | if (ttd < 0) | |
2373 | ttd = 0; | |
2374 | ||
2375 | dest = tw->tw_daddr; | |
2376 | src = tw->tw_rcv_saddr; | |
2377 | destp = ntohs(tw->tw_dport); | |
2378 | srcp = ntohs(tw->tw_sport); | |
2379 | ||
2380 | sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" | |
2381 | " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p", | |
2382 | i, src, srcp, dest, destp, tw->tw_substate, 0, 0, | |
2383 | 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, | |
2384 | atomic_read(&tw->tw_refcnt), tw); | |
2385 | } | |
2386 | ||
2387 | #define TMPSZ 150 | |
2388 | ||
2389 | static int tcp4_seq_show(struct seq_file *seq, void *v) | |
2390 | { | |
2391 | struct tcp_iter_state* st; | |
2392 | char tmpbuf[TMPSZ + 1]; | |
2393 | ||
2394 | if (v == SEQ_START_TOKEN) { | |
2395 | seq_printf(seq, "%-*s\n", TMPSZ - 1, | |
2396 | " sl local_address rem_address st tx_queue " | |
2397 | "rx_queue tr tm->when retrnsmt uid timeout " | |
2398 | "inode"); | |
2399 | goto out; | |
2400 | } | |
2401 | st = seq->private; | |
2402 | ||
2403 | switch (st->state) { | |
2404 | case TCP_SEQ_STATE_LISTENING: | |
2405 | case TCP_SEQ_STATE_ESTABLISHED: | |
2406 | get_tcp4_sock(v, tmpbuf, st->num); | |
2407 | break; | |
2408 | case TCP_SEQ_STATE_OPENREQ: | |
2409 | get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid); | |
2410 | break; | |
2411 | case TCP_SEQ_STATE_TIME_WAIT: | |
2412 | get_timewait4_sock(v, tmpbuf, st->num); | |
2413 | break; | |
2414 | } | |
2415 | seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf); | |
2416 | out: | |
2417 | return 0; | |
2418 | } | |
2419 | ||
2420 | static struct file_operations tcp4_seq_fops; | |
2421 | static struct tcp_seq_afinfo tcp4_seq_afinfo = { | |
2422 | .owner = THIS_MODULE, | |
2423 | .name = "tcp", | |
2424 | .family = AF_INET, | |
2425 | .seq_show = tcp4_seq_show, | |
2426 | .seq_fops = &tcp4_seq_fops, | |
2427 | }; | |
2428 | ||
2429 | int __init tcp4_proc_init(void) | |
2430 | { | |
2431 | return tcp_proc_register(&tcp4_seq_afinfo); | |
2432 | } | |
2433 | ||
2434 | void tcp4_proc_exit(void) | |
2435 | { | |
2436 | tcp_proc_unregister(&tcp4_seq_afinfo); | |
2437 | } | |
2438 | #endif /* CONFIG_PROC_FS */ | |
2439 | ||
2440 | struct proto tcp_prot = { | |
2441 | .name = "TCP", | |
2442 | .owner = THIS_MODULE, | |
2443 | .close = tcp_close, | |
2444 | .connect = tcp_v4_connect, | |
2445 | .disconnect = tcp_disconnect, | |
2446 | .accept = tcp_accept, | |
2447 | .ioctl = tcp_ioctl, | |
2448 | .init = tcp_v4_init_sock, | |
2449 | .destroy = tcp_v4_destroy_sock, | |
2450 | .shutdown = tcp_shutdown, | |
2451 | .setsockopt = tcp_setsockopt, | |
2452 | .getsockopt = tcp_getsockopt, | |
2453 | .sendmsg = tcp_sendmsg, | |
2454 | .recvmsg = tcp_recvmsg, | |
2455 | .backlog_rcv = tcp_v4_do_rcv, | |
2456 | .hash = tcp_v4_hash, | |
2457 | .unhash = tcp_unhash, | |
2458 | .get_port = tcp_v4_get_port, | |
2459 | .enter_memory_pressure = tcp_enter_memory_pressure, | |
2460 | .sockets_allocated = &tcp_sockets_allocated, | |
2461 | .memory_allocated = &tcp_memory_allocated, | |
2462 | .memory_pressure = &tcp_memory_pressure, | |
2463 | .sysctl_mem = sysctl_tcp_mem, | |
2464 | .sysctl_wmem = sysctl_tcp_wmem, | |
2465 | .sysctl_rmem = sysctl_tcp_rmem, | |
2466 | .max_header = MAX_TCP_HEADER, | |
2467 | .obj_size = sizeof(struct tcp_sock), | |
60236fdd | 2468 | .rsk_prot = &tcp_request_sock_ops, |
1da177e4 LT |
2469 | }; |
2470 | ||
2471 | ||
2472 | ||
2473 | void __init tcp_v4_init(struct net_proto_family *ops) | |
2474 | { | |
2475 | int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket); | |
2476 | if (err < 0) | |
2477 | panic("Failed to create the TCP control socket.\n"); | |
2478 | tcp_socket->sk->sk_allocation = GFP_ATOMIC; | |
2479 | inet_sk(tcp_socket->sk)->uc_ttl = -1; | |
2480 | ||
2481 | /* Unhash it so that IP input processing does not even | |
2482 | * see it, we do not wish this socket to see incoming | |
2483 | * packets. | |
2484 | */ | |
2485 | tcp_socket->sk->sk_prot->unhash(tcp_socket->sk); | |
2486 | } | |
2487 | ||
2488 | EXPORT_SYMBOL(ipv4_specific); | |
2489 | EXPORT_SYMBOL(tcp_bind_hash); | |
0f7ff927 | 2490 | EXPORT_SYMBOL(inet_bind_bucket_create); |
1da177e4 LT |
2491 | EXPORT_SYMBOL(tcp_hashinfo); |
2492 | EXPORT_SYMBOL(tcp_inherit_port); | |
2493 | EXPORT_SYMBOL(tcp_listen_wlock); | |
2494 | EXPORT_SYMBOL(tcp_port_rover); | |
2495 | EXPORT_SYMBOL(tcp_prot); | |
2496 | EXPORT_SYMBOL(tcp_put_port); | |
2497 | EXPORT_SYMBOL(tcp_unhash); | |
2498 | EXPORT_SYMBOL(tcp_v4_conn_request); | |
2499 | EXPORT_SYMBOL(tcp_v4_connect); | |
2500 | EXPORT_SYMBOL(tcp_v4_do_rcv); | |
1da177e4 LT |
2501 | EXPORT_SYMBOL(tcp_v4_remember_stamp); |
2502 | EXPORT_SYMBOL(tcp_v4_send_check); | |
2503 | EXPORT_SYMBOL(tcp_v4_syn_recv_sock); | |
2504 | ||
2505 | #ifdef CONFIG_PROC_FS | |
2506 | EXPORT_SYMBOL(tcp_proc_register); | |
2507 | EXPORT_SYMBOL(tcp_proc_unregister); | |
2508 | #endif | |
2509 | EXPORT_SYMBOL(sysctl_local_port_range); | |
1da177e4 LT |
2510 | EXPORT_SYMBOL(sysctl_tcp_low_latency); |
2511 | EXPORT_SYMBOL(sysctl_tcp_tw_reuse); | |
2512 |