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USB: oti6858: cleanup
[linux/fpc-iii.git] / net / ipv4 / tcp_ipv4.c
blob77c1939a2b0d50b2dee673fa450a410cd82bc9c9
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
39 * request_sock handling and moved
40 * most of it into the af independent code.
41 * Added tail drop and some other bugfixes.
42 * Added new listen semantics.
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
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64
65 #include <net/net_namespace.h>
66 #include <net/icmp.h>
67 #include <net/inet_hashtables.h>
68 #include <net/tcp.h>
69 #include <net/transp_v6.h>
70 #include <net/ipv6.h>
71 #include <net/inet_common.h>
72 #include <net/timewait_sock.h>
73 #include <net/xfrm.h>
74 #include <net/netdma.h>
75
76 #include <linux/inet.h>
77 #include <linux/ipv6.h>
78 #include <linux/stddef.h>
79 #include <linux/proc_fs.h>
80 #include <linux/seq_file.h>
81
82 #include <linux/crypto.h>
83 #include <linux/scatterlist.h>
84
85 int sysctl_tcp_tw_reuse __read_mostly;
86 int sysctl_tcp_low_latency __read_mostly;
87
88 /* Check TCP sequence numbers in ICMP packets. */
89 #define ICMP_MIN_LENGTH 8
90
91 /* Socket used for sending RSTs */
92 static struct socket *tcp_socket __read_mostly;
93
94 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
95
96 #ifdef CONFIG_TCP_MD5SIG
97 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
98 __be32 addr);
99 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
100 __be32 saddr, __be32 daddr,
101 struct tcphdr *th, int protocol,
102 unsigned int tcplen);
103 #endif
104
105 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
106 .lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
107 .lhash_users = ATOMIC_INIT(0),
108 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
109 };
110
111 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
112 {
113 return inet_csk_get_port(&tcp_hashinfo, sk, snum,
114 inet_csk_bind_conflict);
115 }
116
117 static void tcp_v4_hash(struct sock *sk)
118 {
119 inet_hash(&tcp_hashinfo, sk);
120 }
121
122 void tcp_unhash(struct sock *sk)
123 {
124 inet_unhash(&tcp_hashinfo, sk);
125 }
126
127 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
128 {
129 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
130 ip_hdr(skb)->saddr,
131 tcp_hdr(skb)->dest,
132 tcp_hdr(skb)->source);
133 }
134
135 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
136 {
137 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
138 struct tcp_sock *tp = tcp_sk(sk);
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (twp == NULL || (sysctl_tcp_tw_reuse &&
153 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
154 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
155 if (tp->write_seq == 0)
156 tp->write_seq = 1;
157 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
158 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
159 sock_hold(sktw);
160 return 1;
161 }
162
163 return 0;
164 }
165
166 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
167
168 /* This will initiate an outgoing connection. */
169 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
170 {
171 struct inet_sock *inet = inet_sk(sk);
172 struct tcp_sock *tp = tcp_sk(sk);
173 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
174 struct rtable *rt;
175 __be32 daddr, nexthop;
176 int tmp;
177 int err;
178
179 if (addr_len < sizeof(struct sockaddr_in))
180 return -EINVAL;
181
182 if (usin->sin_family != AF_INET)
183 return -EAFNOSUPPORT;
184
185 nexthop = daddr = usin->sin_addr.s_addr;
186 if (inet->opt && inet->opt->srr) {
187 if (!daddr)
188 return -EINVAL;
189 nexthop = inet->opt->faddr;
190 }
191
192 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
193 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
194 IPPROTO_TCP,
195 inet->sport, usin->sin_port, sk, 1);
196 if (tmp < 0) {
197 if (tmp == -ENETUNREACH)
198 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
199 return tmp;
200 }
201
202 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
203 ip_rt_put(rt);
204 return -ENETUNREACH;
205 }
206
207 if (!inet->opt || !inet->opt->srr)
208 daddr = rt->rt_dst;
209
210 if (!inet->saddr)
211 inet->saddr = rt->rt_src;
212 inet->rcv_saddr = inet->saddr;
213
214 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
215 /* Reset inherited state */
216 tp->rx_opt.ts_recent = 0;
217 tp->rx_opt.ts_recent_stamp = 0;
218 tp->write_seq = 0;
219 }
220
221 if (tcp_death_row.sysctl_tw_recycle &&
222 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
223 struct inet_peer *peer = rt_get_peer(rt);
224 /*
225 * VJ's idea. We save last timestamp seen from
226 * the destination in peer table, when entering state
227 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
228 * when trying new connection.
229 */
230 if (peer != NULL &&
231 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
232 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
233 tp->rx_opt.ts_recent = peer->tcp_ts;
234 }
235 }
236
237 inet->dport = usin->sin_port;
238 inet->daddr = daddr;
239
240 inet_csk(sk)->icsk_ext_hdr_len = 0;
241 if (inet->opt)
242 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
243
244 tp->rx_opt.mss_clamp = 536;
245
246 /* Socket identity is still unknown (sport may be zero).
247 * However we set state to SYN-SENT and not releasing socket
248 * lock select source port, enter ourselves into the hash tables and
249 * complete initialization after this.
250 */
251 tcp_set_state(sk, TCP_SYN_SENT);
252 err = inet_hash_connect(&tcp_death_row, sk);
253 if (err)
254 goto failure;
255
256 err = ip_route_newports(&rt, IPPROTO_TCP,
257 inet->sport, inet->dport, sk);
258 if (err)
259 goto failure;
260
261 /* OK, now commit destination to socket. */
262 sk->sk_gso_type = SKB_GSO_TCPV4;
263 sk_setup_caps(sk, &rt->u.dst);
264
265 if (!tp->write_seq)
266 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
267 inet->daddr,
268 inet->sport,
269 usin->sin_port);
270
271 inet->id = tp->write_seq ^ jiffies;
272
273 err = tcp_connect(sk);
274 rt = NULL;
275 if (err)
276 goto failure;
277
278 return 0;
279
280 failure:
281 /*
282 * This unhashes the socket and releases the local port,
283 * if necessary.
284 */
285 tcp_set_state(sk, TCP_CLOSE);
286 ip_rt_put(rt);
287 sk->sk_route_caps = 0;
288 inet->dport = 0;
289 return err;
290 }
291
292 /*
293 * This routine does path mtu discovery as defined in RFC1191.
294 */
295 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
296 {
297 struct dst_entry *dst;
298 struct inet_sock *inet = inet_sk(sk);
299
300 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
301 * send out by Linux are always <576bytes so they should go through
302 * unfragmented).
303 */
304 if (sk->sk_state == TCP_LISTEN)
305 return;
306
307 /* We don't check in the destentry if pmtu discovery is forbidden
308 * on this route. We just assume that no packet_to_big packets
309 * are send back when pmtu discovery is not active.
310 * There is a small race when the user changes this flag in the
311 * route, but I think that's acceptable.
312 */
313 if ((dst = __sk_dst_check(sk, 0)) == NULL)
314 return;
315
316 dst->ops->update_pmtu(dst, mtu);
317
318 /* Something is about to be wrong... Remember soft error
319 * for the case, if this connection will not able to recover.
320 */
321 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
322 sk->sk_err_soft = EMSGSIZE;
323
324 mtu = dst_mtu(dst);
325
326 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
327 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
328 tcp_sync_mss(sk, mtu);
329
330 /* Resend the TCP packet because it's
331 * clear that the old packet has been
332 * dropped. This is the new "fast" path mtu
333 * discovery.
334 */
335 tcp_simple_retransmit(sk);
336 } /* else let the usual retransmit timer handle it */
337 }
338
339 /*
340 * This routine is called by the ICMP module when it gets some
341 * sort of error condition. If err < 0 then the socket should
342 * be closed and the error returned to the user. If err > 0
343 * it's just the icmp type << 8 | icmp code. After adjustment
344 * header points to the first 8 bytes of the tcp header. We need
345 * to find the appropriate port.
346 *
347 * The locking strategy used here is very "optimistic". When
348 * someone else accesses the socket the ICMP is just dropped
349 * and for some paths there is no check at all.
350 * A more general error queue to queue errors for later handling
351 * is probably better.
352 *
353 */
354
355 void tcp_v4_err(struct sk_buff *skb, u32 info)
356 {
357 struct iphdr *iph = (struct iphdr *)skb->data;
358 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
359 struct tcp_sock *tp;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(skb)->type;
362 const int code = icmp_hdr(skb)->code;
363 struct sock *sk;
364 __u32 seq;
365 int err;
366
367 if (skb->len < (iph->ihl << 2) + 8) {
368 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
369 return;
370 }
371
372 sk = inet_lookup(skb->dev->nd_net, &tcp_hashinfo, iph->daddr, th->dest,
373 iph->saddr, th->source, inet_iif(skb));
374 if (!sk) {
375 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
376 return;
377 }
378 if (sk->sk_state == TCP_TIME_WAIT) {
379 inet_twsk_put(inet_twsk(sk));
380 return;
381 }
382
383 bh_lock_sock(sk);
384 /* If too many ICMPs get dropped on busy
385 * servers this needs to be solved differently.
386 */
387 if (sock_owned_by_user(sk))
388 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
389
390 if (sk->sk_state == TCP_CLOSE)
391 goto out;
392
393 tp = tcp_sk(sk);
394 seq = ntohl(th->seq);
395 if (sk->sk_state != TCP_LISTEN &&
396 !between(seq, tp->snd_una, tp->snd_nxt)) {
397 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
398 goto out;
399 }
400
401 switch (type) {
402 case ICMP_SOURCE_QUENCH:
403 /* Just silently ignore these. */
404 goto out;
405 case ICMP_PARAMETERPROB:
406 err = EPROTO;
407 break;
408 case ICMP_DEST_UNREACH:
409 if (code > NR_ICMP_UNREACH)
410 goto out;
411
412 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
413 if (!sock_owned_by_user(sk))
414 do_pmtu_discovery(sk, iph, info);
415 goto out;
416 }
417
418 err = icmp_err_convert[code].errno;
419 break;
420 case ICMP_TIME_EXCEEDED:
421 err = EHOSTUNREACH;
422 break;
423 default:
424 goto out;
425 }
426
427 switch (sk->sk_state) {
428 struct request_sock *req, **prev;
429 case TCP_LISTEN:
430 if (sock_owned_by_user(sk))
431 goto out;
432
433 req = inet_csk_search_req(sk, &prev, th->dest,
434 iph->daddr, iph->saddr);
435 if (!req)
436 goto out;
437
438 /* ICMPs are not backlogged, hence we cannot get
439 an established socket here.
440 */
441 BUG_TRAP(!req->sk);
442
443 if (seq != tcp_rsk(req)->snt_isn) {
444 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
445 goto out;
446 }
447
448 /*
449 * Still in SYN_RECV, just remove it silently.
450 * There is no good way to pass the error to the newly
451 * created socket, and POSIX does not want network
452 * errors returned from accept().
453 */
454 inet_csk_reqsk_queue_drop(sk, req, prev);
455 goto out;
456
457 case TCP_SYN_SENT:
458 case TCP_SYN_RECV: /* Cannot happen.
459 It can f.e. if SYNs crossed.
460 */
461 if (!sock_owned_by_user(sk)) {
462 sk->sk_err = err;
463
464 sk->sk_error_report(sk);
465
466 tcp_done(sk);
467 } else {
468 sk->sk_err_soft = err;
469 }
470 goto out;
471 }
472
473 /* If we've already connected we will keep trying
474 * until we time out, or the user gives up.
475 *
476 * rfc1122 4.2.3.9 allows to consider as hard errors
477 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
478 * but it is obsoleted by pmtu discovery).
479 *
480 * Note, that in modern internet, where routing is unreliable
481 * and in each dark corner broken firewalls sit, sending random
482 * errors ordered by their masters even this two messages finally lose
483 * their original sense (even Linux sends invalid PORT_UNREACHs)
484 *
485 * Now we are in compliance with RFCs.
486 * --ANK (980905)
487 */
488
489 inet = inet_sk(sk);
490 if (!sock_owned_by_user(sk) && inet->recverr) {
491 sk->sk_err = err;
492 sk->sk_error_report(sk);
493 } else { /* Only an error on timeout */
494 sk->sk_err_soft = err;
495 }
496
497 out:
498 bh_unlock_sock(sk);
499 sock_put(sk);
500 }
501
502 /* This routine computes an IPv4 TCP checksum. */
503 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
504 {
505 struct inet_sock *inet = inet_sk(sk);
506 struct tcphdr *th = tcp_hdr(skb);
507
508 if (skb->ip_summed == CHECKSUM_PARTIAL) {
509 th->check = ~tcp_v4_check(len, inet->saddr,
510 inet->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 } else {
514 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
515 csum_partial((char *)th,
516 th->doff << 2,
517 skb->csum));
518 }
519 }
520
521 int tcp_v4_gso_send_check(struct sk_buff *skb)
522 {
523 const struct iphdr *iph;
524 struct tcphdr *th;
525
526 if (!pskb_may_pull(skb, sizeof(*th)))
527 return -EINVAL;
528
529 iph = ip_hdr(skb);
530 th = tcp_hdr(skb);
531
532 th->check = 0;
533 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
534 skb->csum_start = skb_transport_header(skb) - skb->head;
535 skb->csum_offset = offsetof(struct tcphdr, check);
536 skb->ip_summed = CHECKSUM_PARTIAL;
537 return 0;
538 }
539
540 /*
541 * This routine will send an RST to the other tcp.
542 *
543 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
544 * for reset.
545 * Answer: if a packet caused RST, it is not for a socket
546 * existing in our system, if it is matched to a socket,
547 * it is just duplicate segment or bug in other side's TCP.
548 * So that we build reply only basing on parameters
549 * arrived with segment.
550 * Exception: precedence violation. We do not implement it in any case.
551 */
552
553 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
554 {
555 struct tcphdr *th = tcp_hdr(skb);
556 struct {
557 struct tcphdr th;
558 #ifdef CONFIG_TCP_MD5SIG
559 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
560 #endif
561 } rep;
562 struct ip_reply_arg arg;
563 #ifdef CONFIG_TCP_MD5SIG
564 struct tcp_md5sig_key *key;
565 #endif
566
567 /* Never send a reset in response to a reset. */
568 if (th->rst)
569 return;
570
571 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
572 return;
573
574 /* Swap the send and the receive. */
575 memset(&rep, 0, sizeof(rep));
576 rep.th.dest = th->source;
577 rep.th.source = th->dest;
578 rep.th.doff = sizeof(struct tcphdr) / 4;
579 rep.th.rst = 1;
580
581 if (th->ack) {
582 rep.th.seq = th->ack_seq;
583 } else {
584 rep.th.ack = 1;
585 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
586 skb->len - (th->doff << 2));
587 }
588
589 memset(&arg, 0, sizeof(arg));
590 arg.iov[0].iov_base = (unsigned char *)&rep;
591 arg.iov[0].iov_len = sizeof(rep.th);
592
593 #ifdef CONFIG_TCP_MD5SIG
594 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
595 if (key) {
596 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
597 (TCPOPT_NOP << 16) |
598 (TCPOPT_MD5SIG << 8) |
599 TCPOLEN_MD5SIG);
600 /* Update length and the length the header thinks exists */
601 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
602 rep.th.doff = arg.iov[0].iov_len / 4;
603
604 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
605 key,
606 ip_hdr(skb)->daddr,
607 ip_hdr(skb)->saddr,
608 &rep.th, IPPROTO_TCP,
609 arg.iov[0].iov_len);
610 }
611 #endif
612 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
613 ip_hdr(skb)->saddr, /* XXX */
614 sizeof(struct tcphdr), IPPROTO_TCP, 0);
615 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
616
617 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
618
619 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
620 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
621 }
622
623 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
624 outside socket context is ugly, certainly. What can I do?
625 */
626
627 static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
628 struct sk_buff *skb, u32 seq, u32 ack,
629 u32 win, u32 ts)
630 {
631 struct tcphdr *th = tcp_hdr(skb);
632 struct {
633 struct tcphdr th;
634 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
635 #ifdef CONFIG_TCP_MD5SIG
636 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
637 #endif
638 ];
639 } rep;
640 struct ip_reply_arg arg;
641 #ifdef CONFIG_TCP_MD5SIG
642 struct tcp_md5sig_key *key;
643 struct tcp_md5sig_key tw_key;
644 #endif
645
646 memset(&rep.th, 0, sizeof(struct tcphdr));
647 memset(&arg, 0, sizeof(arg));
648
649 arg.iov[0].iov_base = (unsigned char *)&rep;
650 arg.iov[0].iov_len = sizeof(rep.th);
651 if (ts) {
652 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
653 (TCPOPT_TIMESTAMP << 8) |
654 TCPOLEN_TIMESTAMP);
655 rep.opt[1] = htonl(tcp_time_stamp);
656 rep.opt[2] = htonl(ts);
657 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
658 }
659
660 /* Swap the send and the receive. */
661 rep.th.dest = th->source;
662 rep.th.source = th->dest;
663 rep.th.doff = arg.iov[0].iov_len / 4;
664 rep.th.seq = htonl(seq);
665 rep.th.ack_seq = htonl(ack);
666 rep.th.ack = 1;
667 rep.th.window = htons(win);
668
669 #ifdef CONFIG_TCP_MD5SIG
670 /*
671 * The SKB holds an imcoming packet, but may not have a valid ->sk
672 * pointer. This is especially the case when we're dealing with a
673 * TIME_WAIT ack, because the sk structure is long gone, and only
674 * the tcp_timewait_sock remains. So the md5 key is stashed in that
675 * structure, and we use it in preference. I believe that (twsk ||
676 * skb->sk) holds true, but we program defensively.
677 */
678 if (!twsk && skb->sk) {
679 key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
680 } else if (twsk && twsk->tw_md5_keylen) {
681 tw_key.key = twsk->tw_md5_key;
682 tw_key.keylen = twsk->tw_md5_keylen;
683 key = &tw_key;
684 } else
685 key = NULL;
686
687 if (key) {
688 int offset = (ts) ? 3 : 0;
689
690 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
691 (TCPOPT_NOP << 16) |
692 (TCPOPT_MD5SIG << 8) |
693 TCPOLEN_MD5SIG);
694 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
695 rep.th.doff = arg.iov[0].iov_len/4;
696
697 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
698 key,
699 ip_hdr(skb)->daddr,
700 ip_hdr(skb)->saddr,
701 &rep.th, IPPROTO_TCP,
702 arg.iov[0].iov_len);
703 }
704 #endif
705 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
706 ip_hdr(skb)->saddr, /* XXX */
707 arg.iov[0].iov_len, IPPROTO_TCP, 0);
708 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
709 if (twsk)
710 arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
711
712 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
713
714 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
715 }
716
717 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
718 {
719 struct inet_timewait_sock *tw = inet_twsk(sk);
720 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
721
722 tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
723 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
724 tcptw->tw_ts_recent);
725
726 inet_twsk_put(tw);
727 }
728
729 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
730 struct request_sock *req)
731 {
732 tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
733 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
734 req->ts_recent);
735 }
736
737 /*
738 * Send a SYN-ACK after having received an ACK.
739 * This still operates on a request_sock only, not on a big
740 * socket.
741 */
742 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
743 struct dst_entry *dst)
744 {
745 const struct inet_request_sock *ireq = inet_rsk(req);
746 int err = -1;
747 struct sk_buff * skb;
748
749 /* First, grab a route. */
750 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
751 goto out;
752
753 skb = tcp_make_synack(sk, dst, req);
754
755 if (skb) {
756 struct tcphdr *th = tcp_hdr(skb);
757
758 th->check = tcp_v4_check(skb->len,
759 ireq->loc_addr,
760 ireq->rmt_addr,
761 csum_partial((char *)th, skb->len,
762 skb->csum));
763
764 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
765 ireq->rmt_addr,
766 ireq->opt);
767 err = net_xmit_eval(err);
768 }
769
770 out:
771 dst_release(dst);
772 return err;
773 }
774
775 /*
776 * IPv4 request_sock destructor.
777 */
778 static void tcp_v4_reqsk_destructor(struct request_sock *req)
779 {
780 kfree(inet_rsk(req)->opt);
781 }
782
783 #ifdef CONFIG_SYN_COOKIES
784 static void syn_flood_warning(struct sk_buff *skb)
785 {
786 static unsigned long warntime;
787
788 if (time_after(jiffies, (warntime + HZ * 60))) {
789 warntime = jiffies;
790 printk(KERN_INFO
791 "possible SYN flooding on port %d. Sending cookies.\n",
792 ntohs(tcp_hdr(skb)->dest));
793 }
794 }
795 #endif
796
797 /*
798 * Save and compile IPv4 options into the request_sock if needed.
799 */
800 static struct ip_options *tcp_v4_save_options(struct sock *sk,
801 struct sk_buff *skb)
802 {
803 struct ip_options *opt = &(IPCB(skb)->opt);
804 struct ip_options *dopt = NULL;
805
806 if (opt && opt->optlen) {
807 int opt_size = optlength(opt);
808 dopt = kmalloc(opt_size, GFP_ATOMIC);
809 if (dopt) {
810 if (ip_options_echo(dopt, skb)) {
811 kfree(dopt);
812 dopt = NULL;
813 }
814 }
815 }
816 return dopt;
817 }
818
819 #ifdef CONFIG_TCP_MD5SIG
820 /*
821 * RFC2385 MD5 checksumming requires a mapping of
822 * IP address->MD5 Key.
823 * We need to maintain these in the sk structure.
824 */
825
826 /* Find the Key structure for an address. */
827 static struct tcp_md5sig_key *
828 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
829 {
830 struct tcp_sock *tp = tcp_sk(sk);
831 int i;
832
833 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
834 return NULL;
835 for (i = 0; i < tp->md5sig_info->entries4; i++) {
836 if (tp->md5sig_info->keys4[i].addr == addr)
837 return &tp->md5sig_info->keys4[i].base;
838 }
839 return NULL;
840 }
841
842 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
843 struct sock *addr_sk)
844 {
845 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
846 }
847
848 EXPORT_SYMBOL(tcp_v4_md5_lookup);
849
850 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
851 struct request_sock *req)
852 {
853 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
854 }
855
856 /* This can be called on a newly created socket, from other files */
857 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
858 u8 *newkey, u8 newkeylen)
859 {
860 /* Add Key to the list */
861 struct tcp_md5sig_key *key;
862 struct tcp_sock *tp = tcp_sk(sk);
863 struct tcp4_md5sig_key *keys;
864
865 key = tcp_v4_md5_do_lookup(sk, addr);
866 if (key) {
867 /* Pre-existing entry - just update that one. */
868 kfree(key->key);
869 key->key = newkey;
870 key->keylen = newkeylen;
871 } else {
872 struct tcp_md5sig_info *md5sig;
873
874 if (!tp->md5sig_info) {
875 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
876 GFP_ATOMIC);
877 if (!tp->md5sig_info) {
878 kfree(newkey);
879 return -ENOMEM;
880 }
881 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
882 }
883 if (tcp_alloc_md5sig_pool() == NULL) {
884 kfree(newkey);
885 return -ENOMEM;
886 }
887 md5sig = tp->md5sig_info;
888
889 if (md5sig->alloced4 == md5sig->entries4) {
890 keys = kmalloc((sizeof(*keys) *
891 (md5sig->entries4 + 1)), GFP_ATOMIC);
892 if (!keys) {
893 kfree(newkey);
894 tcp_free_md5sig_pool();
895 return -ENOMEM;
896 }
897
898 if (md5sig->entries4)
899 memcpy(keys, md5sig->keys4,
900 sizeof(*keys) * md5sig->entries4);
901
902 /* Free old key list, and reference new one */
903 kfree(md5sig->keys4);
904 md5sig->keys4 = keys;
905 md5sig->alloced4++;
906 }
907 md5sig->entries4++;
908 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
909 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
910 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
911 }
912 return 0;
913 }
914
915 EXPORT_SYMBOL(tcp_v4_md5_do_add);
916
917 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
918 u8 *newkey, u8 newkeylen)
919 {
920 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
921 newkey, newkeylen);
922 }
923
924 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
925 {
926 struct tcp_sock *tp = tcp_sk(sk);
927 int i;
928
929 for (i = 0; i < tp->md5sig_info->entries4; i++) {
930 if (tp->md5sig_info->keys4[i].addr == addr) {
931 /* Free the key */
932 kfree(tp->md5sig_info->keys4[i].base.key);
933 tp->md5sig_info->entries4--;
934
935 if (tp->md5sig_info->entries4 == 0) {
936 kfree(tp->md5sig_info->keys4);
937 tp->md5sig_info->keys4 = NULL;
938 tp->md5sig_info->alloced4 = 0;
939 } else if (tp->md5sig_info->entries4 != i) {
940 /* Need to do some manipulation */
941 memmove(&tp->md5sig_info->keys4[i],
942 &tp->md5sig_info->keys4[i+1],
943 (tp->md5sig_info->entries4 - i) *
944 sizeof(struct tcp4_md5sig_key));
945 }
946 tcp_free_md5sig_pool();
947 return 0;
948 }
949 }
950 return -ENOENT;
951 }
952
953 EXPORT_SYMBOL(tcp_v4_md5_do_del);
954
955 static void tcp_v4_clear_md5_list(struct sock *sk)
956 {
957 struct tcp_sock *tp = tcp_sk(sk);
958
959 /* Free each key, then the set of key keys,
960 * the crypto element, and then decrement our
961 * hold on the last resort crypto.
962 */
963 if (tp->md5sig_info->entries4) {
964 int i;
965 for (i = 0; i < tp->md5sig_info->entries4; i++)
966 kfree(tp->md5sig_info->keys4[i].base.key);
967 tp->md5sig_info->entries4 = 0;
968 tcp_free_md5sig_pool();
969 }
970 if (tp->md5sig_info->keys4) {
971 kfree(tp->md5sig_info->keys4);
972 tp->md5sig_info->keys4 = NULL;
973 tp->md5sig_info->alloced4 = 0;
974 }
975 }
976
977 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
978 int optlen)
979 {
980 struct tcp_md5sig cmd;
981 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
982 u8 *newkey;
983
984 if (optlen < sizeof(cmd))
985 return -EINVAL;
986
987 if (copy_from_user(&cmd, optval, sizeof(cmd)))
988 return -EFAULT;
989
990 if (sin->sin_family != AF_INET)
991 return -EINVAL;
992
993 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
994 if (!tcp_sk(sk)->md5sig_info)
995 return -ENOENT;
996 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
997 }
998
999 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1000 return -EINVAL;
1001
1002 if (!tcp_sk(sk)->md5sig_info) {
1003 struct tcp_sock *tp = tcp_sk(sk);
1004 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
1005
1006 if (!p)
1007 return -EINVAL;
1008
1009 tp->md5sig_info = p;
1010 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1011 }
1012
1013 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1014 if (!newkey)
1015 return -ENOMEM;
1016 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1017 newkey, cmd.tcpm_keylen);
1018 }
1019
1020 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1021 __be32 saddr, __be32 daddr,
1022 struct tcphdr *th, int protocol,
1023 unsigned int tcplen)
1024 {
1025 struct scatterlist sg[4];
1026 __u16 data_len;
1027 int block = 0;
1028 __sum16 old_checksum;
1029 struct tcp_md5sig_pool *hp;
1030 struct tcp4_pseudohdr *bp;
1031 struct hash_desc *desc;
1032 int err;
1033 unsigned int nbytes = 0;
1034
1035 /*
1036 * Okay, so RFC2385 is turned on for this connection,
1037 * so we need to generate the MD5 hash for the packet now.
1038 */
1039
1040 hp = tcp_get_md5sig_pool();
1041 if (!hp)
1042 goto clear_hash_noput;
1043
1044 bp = &hp->md5_blk.ip4;
1045 desc = &hp->md5_desc;
1046
1047 /*
1048 * 1. the TCP pseudo-header (in the order: source IP address,
1049 * destination IP address, zero-padded protocol number, and
1050 * segment length)
1051 */
1052 bp->saddr = saddr;
1053 bp->daddr = daddr;
1054 bp->pad = 0;
1055 bp->protocol = protocol;
1056 bp->len = htons(tcplen);
1057
1058 sg_init_table(sg, 4);
1059
1060 sg_set_buf(&sg[block++], bp, sizeof(*bp));
1061 nbytes += sizeof(*bp);
1062
1063 /* 2. the TCP header, excluding options, and assuming a
1064 * checksum of zero/
1065 */
1066 old_checksum = th->check;
1067 th->check = 0;
1068 sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
1069 nbytes += sizeof(struct tcphdr);
1070
1071 /* 3. the TCP segment data (if any) */
1072 data_len = tcplen - (th->doff << 2);
1073 if (data_len > 0) {
1074 unsigned char *data = (unsigned char *)th + (th->doff << 2);
1075 sg_set_buf(&sg[block++], data, data_len);
1076 nbytes += data_len;
1077 }
1078
1079 /* 4. an independently-specified key or password, known to both
1080 * TCPs and presumably connection-specific
1081 */
1082 sg_set_buf(&sg[block++], key->key, key->keylen);
1083 nbytes += key->keylen;
1084
1085 sg_mark_end(&sg[block - 1]);
1086
1087 /* Now store the Hash into the packet */
1088 err = crypto_hash_init(desc);
1089 if (err)
1090 goto clear_hash;
1091 err = crypto_hash_update(desc, sg, nbytes);
1092 if (err)
1093 goto clear_hash;
1094 err = crypto_hash_final(desc, md5_hash);
1095 if (err)
1096 goto clear_hash;
1097
1098 /* Reset header, and free up the crypto */
1099 tcp_put_md5sig_pool();
1100 th->check = old_checksum;
1101
1102 out:
1103 return 0;
1104 clear_hash:
1105 tcp_put_md5sig_pool();
1106 clear_hash_noput:
1107 memset(md5_hash, 0, 16);
1108 goto out;
1109 }
1110
1111 int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1112 struct sock *sk,
1113 struct dst_entry *dst,
1114 struct request_sock *req,
1115 struct tcphdr *th, int protocol,
1116 unsigned int tcplen)
1117 {
1118 __be32 saddr, daddr;
1119
1120 if (sk) {
1121 saddr = inet_sk(sk)->saddr;
1122 daddr = inet_sk(sk)->daddr;
1123 } else {
1124 struct rtable *rt = (struct rtable *)dst;
1125 BUG_ON(!rt);
1126 saddr = rt->rt_src;
1127 daddr = rt->rt_dst;
1128 }
1129 return tcp_v4_do_calc_md5_hash(md5_hash, key,
1130 saddr, daddr,
1131 th, protocol, tcplen);
1132 }
1133
1134 EXPORT_SYMBOL(tcp_v4_calc_md5_hash);
1135
1136 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1137 {
1138 /*
1139 * This gets called for each TCP segment that arrives
1140 * so we want to be efficient.
1141 * We have 3 drop cases:
1142 * o No MD5 hash and one expected.
1143 * o MD5 hash and we're not expecting one.
1144 * o MD5 hash and its wrong.
1145 */
1146 __u8 *hash_location = NULL;
1147 struct tcp_md5sig_key *hash_expected;
1148 const struct iphdr *iph = ip_hdr(skb);
1149 struct tcphdr *th = tcp_hdr(skb);
1150 int length = (th->doff << 2) - sizeof(struct tcphdr);
1151 int genhash;
1152 unsigned char *ptr;
1153 unsigned char newhash[16];
1154
1155 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1156
1157 /*
1158 * If the TCP option length is less than the TCP_MD5SIG
1159 * option length, then we can shortcut
1160 */
1161 if (length < TCPOLEN_MD5SIG) {
1162 if (hash_expected)
1163 return 1;
1164 else
1165 return 0;
1166 }
1167
1168 /* Okay, we can't shortcut - we have to grub through the options */
1169 ptr = (unsigned char *)(th + 1);
1170 while (length > 0) {
1171 int opcode = *ptr++;
1172 int opsize;
1173
1174 switch (opcode) {
1175 case TCPOPT_EOL:
1176 goto done_opts;
1177 case TCPOPT_NOP:
1178 length--;
1179 continue;
1180 default:
1181 opsize = *ptr++;
1182 if (opsize < 2)
1183 goto done_opts;
1184 if (opsize > length)
1185 goto done_opts;
1186
1187 if (opcode == TCPOPT_MD5SIG) {
1188 hash_location = ptr;
1189 goto done_opts;
1190 }
1191 }
1192 ptr += opsize-2;
1193 length -= opsize;
1194 }
1195 done_opts:
1196 /* We've parsed the options - do we have a hash? */
1197 if (!hash_expected && !hash_location)
1198 return 0;
1199
1200 if (hash_expected && !hash_location) {
1201 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
1202 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1203 NIPQUAD(iph->saddr), ntohs(th->source),
1204 NIPQUAD(iph->daddr), ntohs(th->dest));
1205 return 1;
1206 }
1207
1208 if (!hash_expected && hash_location) {
1209 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
1210 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1211 NIPQUAD(iph->saddr), ntohs(th->source),
1212 NIPQUAD(iph->daddr), ntohs(th->dest));
1213 return 1;
1214 }
1215
1216 /* Okay, so this is hash_expected and hash_location -
1217 * so we need to calculate the checksum.
1218 */
1219 genhash = tcp_v4_do_calc_md5_hash(newhash,
1220 hash_expected,
1221 iph->saddr, iph->daddr,
1222 th, sk->sk_protocol,
1223 skb->len);
1224
1225 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1226 if (net_ratelimit()) {
1227 printk(KERN_INFO "MD5 Hash failed for "
1228 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
1229 NIPQUAD(iph->saddr), ntohs(th->source),
1230 NIPQUAD(iph->daddr), ntohs(th->dest),
1231 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1232 }
1233 return 1;
1234 }
1235 return 0;
1236 }
1237
1238 #endif
1239
1240 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1241 .family = PF_INET,
1242 .obj_size = sizeof(struct tcp_request_sock),
1243 .rtx_syn_ack = tcp_v4_send_synack,
1244 .send_ack = tcp_v4_reqsk_send_ack,
1245 .destructor = tcp_v4_reqsk_destructor,
1246 .send_reset = tcp_v4_send_reset,
1247 };
1248
1249 #ifdef CONFIG_TCP_MD5SIG
1250 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1251 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1252 };
1253 #endif
1254
1255 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1256 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1257 .twsk_unique = tcp_twsk_unique,
1258 .twsk_destructor= tcp_twsk_destructor,
1259 };
1260
1261 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1262 {
1263 struct inet_request_sock *ireq;
1264 struct tcp_options_received tmp_opt;
1265 struct request_sock *req;
1266 __be32 saddr = ip_hdr(skb)->saddr;
1267 __be32 daddr = ip_hdr(skb)->daddr;
1268 __u32 isn = TCP_SKB_CB(skb)->when;
1269 struct dst_entry *dst = NULL;
1270 #ifdef CONFIG_SYN_COOKIES
1271 int want_cookie = 0;
1272 #else
1273 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1274 #endif
1275
1276 /* Never answer to SYNs send to broadcast or multicast */
1277 if (((struct rtable *)skb->dst)->rt_flags &
1278 (RTCF_BROADCAST | RTCF_MULTICAST))
1279 goto drop;
1280
1281 /* TW buckets are converted to open requests without
1282 * limitations, they conserve resources and peer is
1283 * evidently real one.
1284 */
1285 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1286 #ifdef CONFIG_SYN_COOKIES
1287 if (sysctl_tcp_syncookies) {
1288 want_cookie = 1;
1289 } else
1290 #endif
1291 goto drop;
1292 }
1293
1294 /* Accept backlog is full. If we have already queued enough
1295 * of warm entries in syn queue, drop request. It is better than
1296 * clogging syn queue with openreqs with exponentially increasing
1297 * timeout.
1298 */
1299 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1300 goto drop;
1301
1302 req = reqsk_alloc(&tcp_request_sock_ops);
1303 if (!req)
1304 goto drop;
1305
1306 #ifdef CONFIG_TCP_MD5SIG
1307 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1308 #endif
1309
1310 tcp_clear_options(&tmp_opt);
1311 tmp_opt.mss_clamp = 536;
1312 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1313
1314 tcp_parse_options(skb, &tmp_opt, 0);
1315
1316 if (want_cookie) {
1317 tcp_clear_options(&tmp_opt);
1318 tmp_opt.saw_tstamp = 0;
1319 }
1320
1321 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1322 /* Some OSes (unknown ones, but I see them on web server, which
1323 * contains information interesting only for windows'
1324 * users) do not send their stamp in SYN. It is easy case.
1325 * We simply do not advertise TS support.
1326 */
1327 tmp_opt.saw_tstamp = 0;
1328 tmp_opt.tstamp_ok = 0;
1329 }
1330 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1331
1332 tcp_openreq_init(req, &tmp_opt, skb);
1333
1334 if (security_inet_conn_request(sk, skb, req))
1335 goto drop_and_free;
1336
1337 ireq = inet_rsk(req);
1338 ireq->loc_addr = daddr;
1339 ireq->rmt_addr = saddr;
1340 ireq->opt = tcp_v4_save_options(sk, skb);
1341 if (!want_cookie)
1342 TCP_ECN_create_request(req, tcp_hdr(skb));
1343
1344 if (want_cookie) {
1345 #ifdef CONFIG_SYN_COOKIES
1346 syn_flood_warning(skb);
1347 #endif
1348 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1349 } else if (!isn) {
1350 struct inet_peer *peer = NULL;
1351
1352 /* VJ's idea. We save last timestamp seen
1353 * from the destination in peer table, when entering
1354 * state TIME-WAIT, and check against it before
1355 * accepting new connection request.
1356 *
1357 * If "isn" is not zero, this request hit alive
1358 * timewait bucket, so that all the necessary checks
1359 * are made in the function processing timewait state.
1360 */
1361 if (tmp_opt.saw_tstamp &&
1362 tcp_death_row.sysctl_tw_recycle &&
1363 (dst = inet_csk_route_req(sk, req)) != NULL &&
1364 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1365 peer->v4daddr == saddr) {
1366 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1367 (s32)(peer->tcp_ts - req->ts_recent) >
1368 TCP_PAWS_WINDOW) {
1369 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1370 dst_release(dst);
1371 goto drop_and_free;
1372 }
1373 }
1374 /* Kill the following clause, if you dislike this way. */
1375 else if (!sysctl_tcp_syncookies &&
1376 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1377 (sysctl_max_syn_backlog >> 2)) &&
1378 (!peer || !peer->tcp_ts_stamp) &&
1379 (!dst || !dst_metric(dst, RTAX_RTT))) {
1380 /* Without syncookies last quarter of
1381 * backlog is filled with destinations,
1382 * proven to be alive.
1383 * It means that we continue to communicate
1384 * to destinations, already remembered
1385 * to the moment of synflood.
1386 */
1387 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
1388 "request from %u.%u.%u.%u/%u\n",
1389 NIPQUAD(saddr),
1390 ntohs(tcp_hdr(skb)->source));
1391 dst_release(dst);
1392 goto drop_and_free;
1393 }
1394
1395 isn = tcp_v4_init_sequence(skb);
1396 }
1397 tcp_rsk(req)->snt_isn = isn;
1398
1399 if (tcp_v4_send_synack(sk, req, dst))
1400 goto drop_and_free;
1401
1402 if (want_cookie) {
1403 reqsk_free(req);
1404 } else {
1405 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1406 }
1407 return 0;
1408
1409 drop_and_free:
1410 reqsk_free(req);
1411 drop:
1412 return 0;
1413 }
1414
1415
1416 /*
1417 * The three way handshake has completed - we got a valid synack -
1418 * now create the new socket.
1419 */
1420 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1421 struct request_sock *req,
1422 struct dst_entry *dst)
1423 {
1424 struct inet_request_sock *ireq;
1425 struct inet_sock *newinet;
1426 struct tcp_sock *newtp;
1427 struct sock *newsk;
1428 #ifdef CONFIG_TCP_MD5SIG
1429 struct tcp_md5sig_key *key;
1430 #endif
1431
1432 if (sk_acceptq_is_full(sk))
1433 goto exit_overflow;
1434
1435 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1436 goto exit;
1437
1438 newsk = tcp_create_openreq_child(sk, req, skb);
1439 if (!newsk)
1440 goto exit;
1441
1442 newsk->sk_gso_type = SKB_GSO_TCPV4;
1443 sk_setup_caps(newsk, dst);
1444
1445 newtp = tcp_sk(newsk);
1446 newinet = inet_sk(newsk);
1447 ireq = inet_rsk(req);
1448 newinet->daddr = ireq->rmt_addr;
1449 newinet->rcv_saddr = ireq->loc_addr;
1450 newinet->saddr = ireq->loc_addr;
1451 newinet->opt = ireq->opt;
1452 ireq->opt = NULL;
1453 newinet->mc_index = inet_iif(skb);
1454 newinet->mc_ttl = ip_hdr(skb)->ttl;
1455 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1456 if (newinet->opt)
1457 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1458 newinet->id = newtp->write_seq ^ jiffies;
1459
1460 tcp_mtup_init(newsk);
1461 tcp_sync_mss(newsk, dst_mtu(dst));
1462 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1463 tcp_initialize_rcv_mss(newsk);
1464
1465 #ifdef CONFIG_TCP_MD5SIG
1466 /* Copy over the MD5 key from the original socket */
1467 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1468 /*
1469 * We're using one, so create a matching key
1470 * on the newsk structure. If we fail to get
1471 * memory, then we end up not copying the key
1472 * across. Shucks.
1473 */
1474 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1475 if (newkey != NULL)
1476 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1477 newkey, key->keylen);
1478 }
1479 #endif
1480
1481 __inet_hash_nolisten(&tcp_hashinfo, newsk);
1482 __inet_inherit_port(&tcp_hashinfo, sk, newsk);
1483
1484 return newsk;
1485
1486 exit_overflow:
1487 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1488 exit:
1489 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1490 dst_release(dst);
1491 return NULL;
1492 }
1493
1494 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1495 {
1496 struct tcphdr *th = tcp_hdr(skb);
1497 const struct iphdr *iph = ip_hdr(skb);
1498 struct sock *nsk;
1499 struct request_sock **prev;
1500 /* Find possible connection requests. */
1501 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1502 iph->saddr, iph->daddr);
1503 if (req)
1504 return tcp_check_req(sk, skb, req, prev);
1505
1506 nsk = inet_lookup_established(sk->sk_net, &tcp_hashinfo, iph->saddr,
1507 th->source, iph->daddr, th->dest, inet_iif(skb));
1508
1509 if (nsk) {
1510 if (nsk->sk_state != TCP_TIME_WAIT) {
1511 bh_lock_sock(nsk);
1512 return nsk;
1513 }
1514 inet_twsk_put(inet_twsk(nsk));
1515 return NULL;
1516 }
1517
1518 #ifdef CONFIG_SYN_COOKIES
1519 if (!th->rst && !th->syn && th->ack)
1520 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1521 #endif
1522 return sk;
1523 }
1524
1525 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1526 {
1527 const struct iphdr *iph = ip_hdr(skb);
1528
1529 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1530 if (!tcp_v4_check(skb->len, iph->saddr,
1531 iph->daddr, skb->csum)) {
1532 skb->ip_summed = CHECKSUM_UNNECESSARY;
1533 return 0;
1534 }
1535 }
1536
1537 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1538 skb->len, IPPROTO_TCP, 0);
1539
1540 if (skb->len <= 76) {
1541 return __skb_checksum_complete(skb);
1542 }
1543 return 0;
1544 }
1545
1546
1547 /* The socket must have it's spinlock held when we get
1548 * here.
1549 *
1550 * We have a potential double-lock case here, so even when
1551 * doing backlog processing we use the BH locking scheme.
1552 * This is because we cannot sleep with the original spinlock
1553 * held.
1554 */
1555 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1556 {
1557 struct sock *rsk;
1558 #ifdef CONFIG_TCP_MD5SIG
1559 /*
1560 * We really want to reject the packet as early as possible
1561 * if:
1562 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1563 * o There is an MD5 option and we're not expecting one
1564 */
1565 if (tcp_v4_inbound_md5_hash(sk, skb))
1566 goto discard;
1567 #endif
1568
1569 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1570 TCP_CHECK_TIMER(sk);
1571 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1572 rsk = sk;
1573 goto reset;
1574 }
1575 TCP_CHECK_TIMER(sk);
1576 return 0;
1577 }
1578
1579 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1580 goto csum_err;
1581
1582 if (sk->sk_state == TCP_LISTEN) {
1583 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1584 if (!nsk)
1585 goto discard;
1586
1587 if (nsk != sk) {
1588 if (tcp_child_process(sk, nsk, skb)) {
1589 rsk = nsk;
1590 goto reset;
1591 }
1592 return 0;
1593 }
1594 }
1595
1596 TCP_CHECK_TIMER(sk);
1597 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1598 rsk = sk;
1599 goto reset;
1600 }
1601 TCP_CHECK_TIMER(sk);
1602 return 0;
1603
1604 reset:
1605 tcp_v4_send_reset(rsk, skb);
1606 discard:
1607 kfree_skb(skb);
1608 /* Be careful here. If this function gets more complicated and
1609 * gcc suffers from register pressure on the x86, sk (in %ebx)
1610 * might be destroyed here. This current version compiles correctly,
1611 * but you have been warned.
1612 */
1613 return 0;
1614
1615 csum_err:
1616 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1617 goto discard;
1618 }
1619
1620 /*
1621 * From tcp_input.c
1622 */
1623
1624 int tcp_v4_rcv(struct sk_buff *skb)
1625 {
1626 const struct iphdr *iph;
1627 struct tcphdr *th;
1628 struct sock *sk;
1629 int ret;
1630
1631 if (skb->pkt_type != PACKET_HOST)
1632 goto discard_it;
1633
1634 /* Count it even if it's bad */
1635 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1636
1637 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1638 goto discard_it;
1639
1640 th = tcp_hdr(skb);
1641
1642 if (th->doff < sizeof(struct tcphdr) / 4)
1643 goto bad_packet;
1644 if (!pskb_may_pull(skb, th->doff * 4))
1645 goto discard_it;
1646
1647 /* An explanation is required here, I think.
1648 * Packet length and doff are validated by header prediction,
1649 * provided case of th->doff==0 is eliminated.
1650 * So, we defer the checks. */
1651 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1652 goto bad_packet;
1653
1654 th = tcp_hdr(skb);
1655 iph = ip_hdr(skb);
1656 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1657 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1658 skb->len - th->doff * 4);
1659 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1660 TCP_SKB_CB(skb)->when = 0;
1661 TCP_SKB_CB(skb)->flags = iph->tos;
1662 TCP_SKB_CB(skb)->sacked = 0;
1663
1664 sk = __inet_lookup(skb->dev->nd_net, &tcp_hashinfo, iph->saddr,
1665 th->source, iph->daddr, th->dest, inet_iif(skb));
1666 if (!sk)
1667 goto no_tcp_socket;
1668
1669 process:
1670 if (sk->sk_state == TCP_TIME_WAIT)
1671 goto do_time_wait;
1672
1673 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1674 goto discard_and_relse;
1675 nf_reset(skb);
1676
1677 if (sk_filter(sk, skb))
1678 goto discard_and_relse;
1679
1680 skb->dev = NULL;
1681
1682 bh_lock_sock_nested(sk);
1683 ret = 0;
1684 if (!sock_owned_by_user(sk)) {
1685 #ifdef CONFIG_NET_DMA
1686 struct tcp_sock *tp = tcp_sk(sk);
1687 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1688 tp->ucopy.dma_chan = get_softnet_dma();
1689 if (tp->ucopy.dma_chan)
1690 ret = tcp_v4_do_rcv(sk, skb);
1691 else
1692 #endif
1693 {
1694 if (!tcp_prequeue(sk, skb))
1695 ret = tcp_v4_do_rcv(sk, skb);
1696 }
1697 } else
1698 sk_add_backlog(sk, skb);
1699 bh_unlock_sock(sk);
1700
1701 sock_put(sk);
1702
1703 return ret;
1704
1705 no_tcp_socket:
1706 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1707 goto discard_it;
1708
1709 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1710 bad_packet:
1711 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1712 } else {
1713 tcp_v4_send_reset(NULL, skb);
1714 }
1715
1716 discard_it:
1717 /* Discard frame. */
1718 kfree_skb(skb);
1719 return 0;
1720
1721 discard_and_relse:
1722 sock_put(sk);
1723 goto discard_it;
1724
1725 do_time_wait:
1726 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1727 inet_twsk_put(inet_twsk(sk));
1728 goto discard_it;
1729 }
1730
1731 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1732 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1733 inet_twsk_put(inet_twsk(sk));
1734 goto discard_it;
1735 }
1736 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1737 case TCP_TW_SYN: {
1738 struct sock *sk2 = inet_lookup_listener(skb->dev->nd_net,
1739 &tcp_hashinfo,
1740 iph->daddr, th->dest,
1741 inet_iif(skb));
1742 if (sk2) {
1743 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1744 inet_twsk_put(inet_twsk(sk));
1745 sk = sk2;
1746 goto process;
1747 }
1748 /* Fall through to ACK */
1749 }
1750 case TCP_TW_ACK:
1751 tcp_v4_timewait_ack(sk, skb);
1752 break;
1753 case TCP_TW_RST:
1754 goto no_tcp_socket;
1755 case TCP_TW_SUCCESS:;
1756 }
1757 goto discard_it;
1758 }
1759
1760 /* VJ's idea. Save last timestamp seen from this destination
1761 * and hold it at least for normal timewait interval to use for duplicate
1762 * segment detection in subsequent connections, before they enter synchronized
1763 * state.
1764 */
1765
1766 int tcp_v4_remember_stamp(struct sock *sk)
1767 {
1768 struct inet_sock *inet = inet_sk(sk);
1769 struct tcp_sock *tp = tcp_sk(sk);
1770 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1771 struct inet_peer *peer = NULL;
1772 int release_it = 0;
1773
1774 if (!rt || rt->rt_dst != inet->daddr) {
1775 peer = inet_getpeer(inet->daddr, 1);
1776 release_it = 1;
1777 } else {
1778 if (!rt->peer)
1779 rt_bind_peer(rt, 1);
1780 peer = rt->peer;
1781 }
1782
1783 if (peer) {
1784 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1785 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1786 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1787 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1788 peer->tcp_ts = tp->rx_opt.ts_recent;
1789 }
1790 if (release_it)
1791 inet_putpeer(peer);
1792 return 1;
1793 }
1794
1795 return 0;
1796 }
1797
1798 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1799 {
1800 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1801
1802 if (peer) {
1803 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1804
1805 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1806 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1807 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1808 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1809 peer->tcp_ts = tcptw->tw_ts_recent;
1810 }
1811 inet_putpeer(peer);
1812 return 1;
1813 }
1814
1815 return 0;
1816 }
1817
1818 struct inet_connection_sock_af_ops ipv4_specific = {
1819 .queue_xmit = ip_queue_xmit,
1820 .send_check = tcp_v4_send_check,
1821 .rebuild_header = inet_sk_rebuild_header,
1822 .conn_request = tcp_v4_conn_request,
1823 .syn_recv_sock = tcp_v4_syn_recv_sock,
1824 .remember_stamp = tcp_v4_remember_stamp,
1825 .net_header_len = sizeof(struct iphdr),
1826 .setsockopt = ip_setsockopt,
1827 .getsockopt = ip_getsockopt,
1828 .addr2sockaddr = inet_csk_addr2sockaddr,
1829 .sockaddr_len = sizeof(struct sockaddr_in),
1830 #ifdef CONFIG_COMPAT
1831 .compat_setsockopt = compat_ip_setsockopt,
1832 .compat_getsockopt = compat_ip_getsockopt,
1833 #endif
1834 };
1835
1836 #ifdef CONFIG_TCP_MD5SIG
1837 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1838 .md5_lookup = tcp_v4_md5_lookup,
1839 .calc_md5_hash = tcp_v4_calc_md5_hash,
1840 .md5_add = tcp_v4_md5_add_func,
1841 .md5_parse = tcp_v4_parse_md5_keys,
1842 };
1843 #endif
1844
1845 /* NOTE: A lot of things set to zero explicitly by call to
1846 * sk_alloc() so need not be done here.
1847 */
1848 static int tcp_v4_init_sock(struct sock *sk)
1849 {
1850 struct inet_connection_sock *icsk = inet_csk(sk);
1851 struct tcp_sock *tp = tcp_sk(sk);
1852
1853 skb_queue_head_init(&tp->out_of_order_queue);
1854 tcp_init_xmit_timers(sk);
1855 tcp_prequeue_init(tp);
1856
1857 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1858 tp->mdev = TCP_TIMEOUT_INIT;
1859
1860 /* So many TCP implementations out there (incorrectly) count the
1861 * initial SYN frame in their delayed-ACK and congestion control
1862 * algorithms that we must have the following bandaid to talk
1863 * efficiently to them. -DaveM
1864 */
1865 tp->snd_cwnd = 2;
1866
1867 /* See draft-stevens-tcpca-spec-01 for discussion of the
1868 * initialization of these values.
1869 */
1870 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1871 tp->snd_cwnd_clamp = ~0;
1872 tp->mss_cache = 536;
1873
1874 tp->reordering = sysctl_tcp_reordering;
1875 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1876
1877 sk->sk_state = TCP_CLOSE;
1878
1879 sk->sk_write_space = sk_stream_write_space;
1880 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1881
1882 icsk->icsk_af_ops = &ipv4_specific;
1883 icsk->icsk_sync_mss = tcp_sync_mss;
1884 #ifdef CONFIG_TCP_MD5SIG
1885 tp->af_specific = &tcp_sock_ipv4_specific;
1886 #endif
1887
1888 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1889 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1890
1891 atomic_inc(&tcp_sockets_allocated);
1892
1893 return 0;
1894 }
1895
1896 int tcp_v4_destroy_sock(struct sock *sk)
1897 {
1898 struct tcp_sock *tp = tcp_sk(sk);
1899
1900 tcp_clear_xmit_timers(sk);
1901
1902 tcp_cleanup_congestion_control(sk);
1903
1904 /* Cleanup up the write buffer. */
1905 tcp_write_queue_purge(sk);
1906
1907 /* Cleans up our, hopefully empty, out_of_order_queue. */
1908 __skb_queue_purge(&tp->out_of_order_queue);
1909
1910 #ifdef CONFIG_TCP_MD5SIG
1911 /* Clean up the MD5 key list, if any */
1912 if (tp->md5sig_info) {
1913 tcp_v4_clear_md5_list(sk);
1914 kfree(tp->md5sig_info);
1915 tp->md5sig_info = NULL;
1916 }
1917 #endif
1918
1919 #ifdef CONFIG_NET_DMA
1920 /* Cleans up our sk_async_wait_queue */
1921 __skb_queue_purge(&sk->sk_async_wait_queue);
1922 #endif
1923
1924 /* Clean prequeue, it must be empty really */
1925 __skb_queue_purge(&tp->ucopy.prequeue);
1926
1927 /* Clean up a referenced TCP bind bucket. */
1928 if (inet_csk(sk)->icsk_bind_hash)
1929 inet_put_port(&tcp_hashinfo, sk);
1930
1931 /*
1932 * If sendmsg cached page exists, toss it.
1933 */
1934 if (sk->sk_sndmsg_page) {
1935 __free_page(sk->sk_sndmsg_page);
1936 sk->sk_sndmsg_page = NULL;
1937 }
1938
1939 atomic_dec(&tcp_sockets_allocated);
1940
1941 return 0;
1942 }
1943
1944 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1945
1946 #ifdef CONFIG_PROC_FS
1947 /* Proc filesystem TCP sock list dumping. */
1948
1949 static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1950 {
1951 return hlist_empty(head) ? NULL :
1952 list_entry(head->first, struct inet_timewait_sock, tw_node);
1953 }
1954
1955 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1956 {
1957 return tw->tw_node.next ?
1958 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1959 }
1960
1961 static void *listening_get_next(struct seq_file *seq, void *cur)
1962 {
1963 struct inet_connection_sock *icsk;
1964 struct hlist_node *node;
1965 struct sock *sk = cur;
1966 struct tcp_iter_state* st = seq->private;
1967
1968 if (!sk) {
1969 st->bucket = 0;
1970 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1971 goto get_sk;
1972 }
1973
1974 ++st->num;
1975
1976 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1977 struct request_sock *req = cur;
1978
1979 icsk = inet_csk(st->syn_wait_sk);
1980 req = req->dl_next;
1981 while (1) {
1982 while (req) {
1983 if (req->rsk_ops->family == st->family) {
1984 cur = req;
1985 goto out;
1986 }
1987 req = req->dl_next;
1988 }
1989 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1990 break;
1991 get_req:
1992 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1993 }
1994 sk = sk_next(st->syn_wait_sk);
1995 st->state = TCP_SEQ_STATE_LISTENING;
1996 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1997 } else {
1998 icsk = inet_csk(sk);
1999 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2000 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2001 goto start_req;
2002 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2003 sk = sk_next(sk);
2004 }
2005 get_sk:
2006 sk_for_each_from(sk, node) {
2007 if (sk->sk_family == st->family) {
2008 cur = sk;
2009 goto out;
2010 }
2011 icsk = inet_csk(sk);
2012 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2013 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2014 start_req:
2015 st->uid = sock_i_uid(sk);
2016 st->syn_wait_sk = sk;
2017 st->state = TCP_SEQ_STATE_OPENREQ;
2018 st->sbucket = 0;
2019 goto get_req;
2020 }
2021 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2022 }
2023 if (++st->bucket < INET_LHTABLE_SIZE) {
2024 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
2025 goto get_sk;
2026 }
2027 cur = NULL;
2028 out:
2029 return cur;
2030 }
2031
2032 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2033 {
2034 void *rc = listening_get_next(seq, NULL);
2035
2036 while (rc && *pos) {
2037 rc = listening_get_next(seq, rc);
2038 --*pos;
2039 }
2040 return rc;
2041 }
2042
2043 static void *established_get_first(struct seq_file *seq)
2044 {
2045 struct tcp_iter_state* st = seq->private;
2046 void *rc = NULL;
2047
2048 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2049 struct sock *sk;
2050 struct hlist_node *node;
2051 struct inet_timewait_sock *tw;
2052 rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2053
2054 read_lock_bh(lock);
2055 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2056 if (sk->sk_family != st->family) {
2057 continue;
2058 }
2059 rc = sk;
2060 goto out;
2061 }
2062 st->state = TCP_SEQ_STATE_TIME_WAIT;
2063 inet_twsk_for_each(tw, node,
2064 &tcp_hashinfo.ehash[st->bucket].twchain) {
2065 if (tw->tw_family != st->family) {
2066 continue;
2067 }
2068 rc = tw;
2069 goto out;
2070 }
2071 read_unlock_bh(lock);
2072 st->state = TCP_SEQ_STATE_ESTABLISHED;
2073 }
2074 out:
2075 return rc;
2076 }
2077
2078 static void *established_get_next(struct seq_file *seq, void *cur)
2079 {
2080 struct sock *sk = cur;
2081 struct inet_timewait_sock *tw;
2082 struct hlist_node *node;
2083 struct tcp_iter_state* st = seq->private;
2084
2085 ++st->num;
2086
2087 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2088 tw = cur;
2089 tw = tw_next(tw);
2090 get_tw:
2091 while (tw && tw->tw_family != st->family) {
2092 tw = tw_next(tw);
2093 }
2094 if (tw) {
2095 cur = tw;
2096 goto out;
2097 }
2098 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2099 st->state = TCP_SEQ_STATE_ESTABLISHED;
2100
2101 if (++st->bucket < tcp_hashinfo.ehash_size) {
2102 read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2103 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
2104 } else {
2105 cur = NULL;
2106 goto out;
2107 }
2108 } else
2109 sk = sk_next(sk);
2110
2111 sk_for_each_from(sk, node) {
2112 if (sk->sk_family == st->family)
2113 goto found;
2114 }
2115
2116 st->state = TCP_SEQ_STATE_TIME_WAIT;
2117 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2118 goto get_tw;
2119 found:
2120 cur = sk;
2121 out:
2122 return cur;
2123 }
2124
2125 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2126 {
2127 void *rc = established_get_first(seq);
2128
2129 while (rc && pos) {
2130 rc = established_get_next(seq, rc);
2131 --pos;
2132 }
2133 return rc;
2134 }
2135
2136 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2137 {
2138 void *rc;
2139 struct tcp_iter_state* st = seq->private;
2140
2141 inet_listen_lock(&tcp_hashinfo);
2142 st->state = TCP_SEQ_STATE_LISTENING;
2143 rc = listening_get_idx(seq, &pos);
2144
2145 if (!rc) {
2146 inet_listen_unlock(&tcp_hashinfo);
2147 st->state = TCP_SEQ_STATE_ESTABLISHED;
2148 rc = established_get_idx(seq, pos);
2149 }
2150
2151 return rc;
2152 }
2153
2154 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2155 {
2156 struct tcp_iter_state* st = seq->private;
2157 st->state = TCP_SEQ_STATE_LISTENING;
2158 st->num = 0;
2159 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2160 }
2161
2162 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2163 {
2164 void *rc = NULL;
2165 struct tcp_iter_state* st;
2166
2167 if (v == SEQ_START_TOKEN) {
2168 rc = tcp_get_idx(seq, 0);
2169 goto out;
2170 }
2171 st = seq->private;
2172
2173 switch (st->state) {
2174 case TCP_SEQ_STATE_OPENREQ:
2175 case TCP_SEQ_STATE_LISTENING:
2176 rc = listening_get_next(seq, v);
2177 if (!rc) {
2178 inet_listen_unlock(&tcp_hashinfo);
2179 st->state = TCP_SEQ_STATE_ESTABLISHED;
2180 rc = established_get_first(seq);
2181 }
2182 break;
2183 case TCP_SEQ_STATE_ESTABLISHED:
2184 case TCP_SEQ_STATE_TIME_WAIT:
2185 rc = established_get_next(seq, v);
2186 break;
2187 }
2188 out:
2189 ++*pos;
2190 return rc;
2191 }
2192
2193 static void tcp_seq_stop(struct seq_file *seq, void *v)
2194 {
2195 struct tcp_iter_state* st = seq->private;
2196
2197 switch (st->state) {
2198 case TCP_SEQ_STATE_OPENREQ:
2199 if (v) {
2200 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2201 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2202 }
2203 case TCP_SEQ_STATE_LISTENING:
2204 if (v != SEQ_START_TOKEN)
2205 inet_listen_unlock(&tcp_hashinfo);
2206 break;
2207 case TCP_SEQ_STATE_TIME_WAIT:
2208 case TCP_SEQ_STATE_ESTABLISHED:
2209 if (v)
2210 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2211 break;
2212 }
2213 }
2214
2215 static int tcp_seq_open(struct inode *inode, struct file *file)
2216 {
2217 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2218 struct seq_file *seq;
2219 struct tcp_iter_state *s;
2220 int rc;
2221
2222 if (unlikely(afinfo == NULL))
2223 return -EINVAL;
2224
2225 s = kzalloc(sizeof(*s), GFP_KERNEL);
2226 if (!s)
2227 return -ENOMEM;
2228 s->family = afinfo->family;
2229 s->seq_ops.start = tcp_seq_start;
2230 s->seq_ops.next = tcp_seq_next;
2231 s->seq_ops.show = afinfo->seq_show;
2232 s->seq_ops.stop = tcp_seq_stop;
2233
2234 rc = seq_open(file, &s->seq_ops);
2235 if (rc)
2236 goto out_kfree;
2237 seq = file->private_data;
2238 seq->private = s;
2239 out:
2240 return rc;
2241 out_kfree:
2242 kfree(s);
2243 goto out;
2244 }
2245
2246 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
2247 {
2248 int rc = 0;
2249 struct proc_dir_entry *p;
2250
2251 if (!afinfo)
2252 return -EINVAL;
2253 afinfo->seq_fops->owner = afinfo->owner;
2254 afinfo->seq_fops->open = tcp_seq_open;
2255 afinfo->seq_fops->read = seq_read;
2256 afinfo->seq_fops->llseek = seq_lseek;
2257 afinfo->seq_fops->release = seq_release_private;
2258
2259 p = proc_net_fops_create(&init_net, afinfo->name, S_IRUGO, afinfo->seq_fops);
2260 if (p)
2261 p->data = afinfo;
2262 else
2263 rc = -ENOMEM;
2264 return rc;
2265 }
2266
2267 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
2268 {
2269 if (!afinfo)
2270 return;
2271 proc_net_remove(&init_net, afinfo->name);
2272 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
2273 }
2274
2275 static void get_openreq4(struct sock *sk, struct request_sock *req,
2276 char *tmpbuf, int i, int uid)
2277 {
2278 const struct inet_request_sock *ireq = inet_rsk(req);
2279 int ttd = req->expires - jiffies;
2280
2281 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2282 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
2283 i,
2284 ireq->loc_addr,
2285 ntohs(inet_sk(sk)->sport),
2286 ireq->rmt_addr,
2287 ntohs(ireq->rmt_port),
2288 TCP_SYN_RECV,
2289 0, 0, /* could print option size, but that is af dependent. */
2290 1, /* timers active (only the expire timer) */
2291 jiffies_to_clock_t(ttd),
2292 req->retrans,
2293 uid,
2294 0, /* non standard timer */
2295 0, /* open_requests have no inode */
2296 atomic_read(&sk->sk_refcnt),
2297 req);
2298 }
2299
2300 static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
2301 {
2302 int timer_active;
2303 unsigned long timer_expires;
2304 struct tcp_sock *tp = tcp_sk(sk);
2305 const struct inet_connection_sock *icsk = inet_csk(sk);
2306 struct inet_sock *inet = inet_sk(sk);
2307 __be32 dest = inet->daddr;
2308 __be32 src = inet->rcv_saddr;
2309 __u16 destp = ntohs(inet->dport);
2310 __u16 srcp = ntohs(inet->sport);
2311
2312 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2313 timer_active = 1;
2314 timer_expires = icsk->icsk_timeout;
2315 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2316 timer_active = 4;
2317 timer_expires = icsk->icsk_timeout;
2318 } else if (timer_pending(&sk->sk_timer)) {
2319 timer_active = 2;
2320 timer_expires = sk->sk_timer.expires;
2321 } else {
2322 timer_active = 0;
2323 timer_expires = jiffies;
2324 }
2325
2326 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2327 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
2328 i, src, srcp, dest, destp, sk->sk_state,
2329 tp->write_seq - tp->snd_una,
2330 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2331 (tp->rcv_nxt - tp->copied_seq),
2332 timer_active,
2333 jiffies_to_clock_t(timer_expires - jiffies),
2334 icsk->icsk_retransmits,
2335 sock_i_uid(sk),
2336 icsk->icsk_probes_out,
2337 sock_i_ino(sk),
2338 atomic_read(&sk->sk_refcnt), sk,
2339 icsk->icsk_rto,
2340 icsk->icsk_ack.ato,
2341 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2342 tp->snd_cwnd,
2343 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
2344 }
2345
2346 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2347 char *tmpbuf, int i)
2348 {
2349 __be32 dest, src;
2350 __u16 destp, srcp;
2351 int ttd = tw->tw_ttd - jiffies;
2352
2353 if (ttd < 0)
2354 ttd = 0;
2355
2356 dest = tw->tw_daddr;
2357 src = tw->tw_rcv_saddr;
2358 destp = ntohs(tw->tw_dport);
2359 srcp = ntohs(tw->tw_sport);
2360
2361 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2362 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
2363 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2364 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2365 atomic_read(&tw->tw_refcnt), tw);
2366 }
2367
2368 #define TMPSZ 150
2369
2370 static int tcp4_seq_show(struct seq_file *seq, void *v)
2371 {
2372 struct tcp_iter_state* st;
2373 char tmpbuf[TMPSZ + 1];
2374
2375 if (v == SEQ_START_TOKEN) {
2376 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2377 " sl local_address rem_address st tx_queue "
2378 "rx_queue tr tm->when retrnsmt uid timeout "
2379 "inode");
2380 goto out;
2381 }
2382 st = seq->private;
2383
2384 switch (st->state) {
2385 case TCP_SEQ_STATE_LISTENING:
2386 case TCP_SEQ_STATE_ESTABLISHED:
2387 get_tcp4_sock(v, tmpbuf, st->num);
2388 break;
2389 case TCP_SEQ_STATE_OPENREQ:
2390 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
2391 break;
2392 case TCP_SEQ_STATE_TIME_WAIT:
2393 get_timewait4_sock(v, tmpbuf, st->num);
2394 break;
2395 }
2396 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
2397 out:
2398 return 0;
2399 }
2400
2401 static struct file_operations tcp4_seq_fops;
2402 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2403 .owner = THIS_MODULE,
2404 .name = "tcp",
2405 .family = AF_INET,
2406 .seq_show = tcp4_seq_show,
2407 .seq_fops = &tcp4_seq_fops,
2408 };
2409
2410 int __init tcp4_proc_init(void)
2411 {
2412 return tcp_proc_register(&tcp4_seq_afinfo);
2413 }
2414
2415 void tcp4_proc_exit(void)
2416 {
2417 tcp_proc_unregister(&tcp4_seq_afinfo);
2418 }
2419 #endif /* CONFIG_PROC_FS */
2420
2421 DEFINE_PROTO_INUSE(tcp)
2422
2423 struct proto tcp_prot = {
2424 .name = "TCP",
2425 .owner = THIS_MODULE,
2426 .close = tcp_close,
2427 .connect = tcp_v4_connect,
2428 .disconnect = tcp_disconnect,
2429 .accept = inet_csk_accept,
2430 .ioctl = tcp_ioctl,
2431 .init = tcp_v4_init_sock,
2432 .destroy = tcp_v4_destroy_sock,
2433 .shutdown = tcp_shutdown,
2434 .setsockopt = tcp_setsockopt,
2435 .getsockopt = tcp_getsockopt,
2436 .recvmsg = tcp_recvmsg,
2437 .backlog_rcv = tcp_v4_do_rcv,
2438 .hash = tcp_v4_hash,
2439 .unhash = tcp_unhash,
2440 .get_port = tcp_v4_get_port,
2441 .enter_memory_pressure = tcp_enter_memory_pressure,
2442 .sockets_allocated = &tcp_sockets_allocated,
2443 .orphan_count = &tcp_orphan_count,
2444 .memory_allocated = &tcp_memory_allocated,
2445 .memory_pressure = &tcp_memory_pressure,
2446 .sysctl_mem = sysctl_tcp_mem,
2447 .sysctl_wmem = sysctl_tcp_wmem,
2448 .sysctl_rmem = sysctl_tcp_rmem,
2449 .max_header = MAX_TCP_HEADER,
2450 .obj_size = sizeof(struct tcp_sock),
2451 .twsk_prot = &tcp_timewait_sock_ops,
2452 .rsk_prot = &tcp_request_sock_ops,
2453 #ifdef CONFIG_COMPAT
2454 .compat_setsockopt = compat_tcp_setsockopt,
2455 .compat_getsockopt = compat_tcp_getsockopt,
2456 #endif
2457 REF_PROTO_INUSE(tcp)
2458 };
2459
2460 void __init tcp_v4_init(struct net_proto_family *ops)
2461 {
2462 if (inet_csk_ctl_sock_create(&tcp_socket, PF_INET, SOCK_RAW,
2463 IPPROTO_TCP) < 0)
2464 panic("Failed to create the TCP control socket.\n");
2465 }
2466
2467 EXPORT_SYMBOL(ipv4_specific);
2468 EXPORT_SYMBOL(tcp_hashinfo);
2469 EXPORT_SYMBOL(tcp_prot);
2470 EXPORT_SYMBOL(tcp_unhash);
2471 EXPORT_SYMBOL(tcp_v4_conn_request);
2472 EXPORT_SYMBOL(tcp_v4_connect);
2473 EXPORT_SYMBOL(tcp_v4_do_rcv);
2474 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2475 EXPORT_SYMBOL(tcp_v4_send_check);
2476 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2477
2478 #ifdef CONFIG_PROC_FS
2479 EXPORT_SYMBOL(tcp_proc_register);
2480 EXPORT_SYMBOL(tcp_proc_unregister);
2481 #endif
2482 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2483
Linux with added FPC-III support