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sfc: Fix unreliable link detection in some loopback modes
[linux-2.6/verdex.git] / net / ipv4 / tcp_ipv4.c
blob10172487921b944d3f82b1d527b4674a9af449a4
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 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24 /*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53
54 #include <linux/types.h>
55 #include <linux/fcntl.h>
56 #include <linux/module.h>
57 #include <linux/random.h>
58 #include <linux/cache.h>
59 #include <linux/jhash.h>
60 #include <linux/init.h>
61 #include <linux/times.h>
62
63 #include <net/net_namespace.h>
64 #include <net/icmp.h>
65 #include <net/inet_hashtables.h>
66 #include <net/tcp.h>
67 #include <net/transp_v6.h>
68 #include <net/ipv6.h>
69 #include <net/inet_common.h>
70 #include <net/timewait_sock.h>
71 #include <net/xfrm.h>
72 #include <net/netdma.h>
73
74 #include <linux/inet.h>
75 #include <linux/ipv6.h>
76 #include <linux/stddef.h>
77 #include <linux/proc_fs.h>
78 #include <linux/seq_file.h>
79
80 #include <linux/crypto.h>
81 #include <linux/scatterlist.h>
82
83 int sysctl_tcp_tw_reuse __read_mostly;
84 int sysctl_tcp_low_latency __read_mostly;
85
86
87 #ifdef CONFIG_TCP_MD5SIG
88 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
89 __be32 addr);
90 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
91 __be32 daddr, __be32 saddr, struct tcphdr *th);
92 #else
93 static inline
94 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
95 {
96 return NULL;
97 }
98 #endif
99
100 struct inet_hashinfo tcp_hashinfo;
101
102 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
103 {
104 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
105 ip_hdr(skb)->saddr,
106 tcp_hdr(skb)->dest,
107 tcp_hdr(skb)->source);
108 }
109
110 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
111 {
112 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
113 struct tcp_sock *tp = tcp_sk(sk);
114
115 /* With PAWS, it is safe from the viewpoint
116 of data integrity. Even without PAWS it is safe provided sequence
117 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
118
119 Actually, the idea is close to VJ's one, only timestamp cache is
120 held not per host, but per port pair and TW bucket is used as state
121 holder.
122
123 If TW bucket has been already destroyed we fall back to VJ's scheme
124 and use initial timestamp retrieved from peer table.
125 */
126 if (tcptw->tw_ts_recent_stamp &&
127 (twp == NULL || (sysctl_tcp_tw_reuse &&
128 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
129 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
130 if (tp->write_seq == 0)
131 tp->write_seq = 1;
132 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
133 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
134 sock_hold(sktw);
135 return 1;
136 }
137
138 return 0;
139 }
140
141 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
142
143 /* This will initiate an outgoing connection. */
144 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
145 {
146 struct inet_sock *inet = inet_sk(sk);
147 struct tcp_sock *tp = tcp_sk(sk);
148 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
149 struct rtable *rt;
150 __be32 daddr, nexthop;
151 int tmp;
152 int err;
153
154 if (addr_len < sizeof(struct sockaddr_in))
155 return -EINVAL;
156
157 if (usin->sin_family != AF_INET)
158 return -EAFNOSUPPORT;
159
160 nexthop = daddr = usin->sin_addr.s_addr;
161 if (inet->opt && inet->opt->srr) {
162 if (!daddr)
163 return -EINVAL;
164 nexthop = inet->opt->faddr;
165 }
166
167 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
168 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
169 IPPROTO_TCP,
170 inet->sport, usin->sin_port, sk, 1);
171 if (tmp < 0) {
172 if (tmp == -ENETUNREACH)
173 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
174 return tmp;
175 }
176
177 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
178 ip_rt_put(rt);
179 return -ENETUNREACH;
180 }
181
182 if (!inet->opt || !inet->opt->srr)
183 daddr = rt->rt_dst;
184
185 if (!inet->saddr)
186 inet->saddr = rt->rt_src;
187 inet->rcv_saddr = inet->saddr;
188
189 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
190 /* Reset inherited state */
191 tp->rx_opt.ts_recent = 0;
192 tp->rx_opt.ts_recent_stamp = 0;
193 tp->write_seq = 0;
194 }
195
196 if (tcp_death_row.sysctl_tw_recycle &&
197 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
198 struct inet_peer *peer = rt_get_peer(rt);
199 /*
200 * VJ's idea. We save last timestamp seen from
201 * the destination in peer table, when entering state
202 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
203 * when trying new connection.
204 */
205 if (peer != NULL &&
206 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
207 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
208 tp->rx_opt.ts_recent = peer->tcp_ts;
209 }
210 }
211
212 inet->dport = usin->sin_port;
213 inet->daddr = daddr;
214
215 inet_csk(sk)->icsk_ext_hdr_len = 0;
216 if (inet->opt)
217 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
218
219 tp->rx_opt.mss_clamp = 536;
220
221 /* Socket identity is still unknown (sport may be zero).
222 * However we set state to SYN-SENT and not releasing socket
223 * lock select source port, enter ourselves into the hash tables and
224 * complete initialization after this.
225 */
226 tcp_set_state(sk, TCP_SYN_SENT);
227 err = inet_hash_connect(&tcp_death_row, sk);
228 if (err)
229 goto failure;
230
231 err = ip_route_newports(&rt, IPPROTO_TCP,
232 inet->sport, inet->dport, sk);
233 if (err)
234 goto failure;
235
236 /* OK, now commit destination to socket. */
237 sk->sk_gso_type = SKB_GSO_TCPV4;
238 sk_setup_caps(sk, &rt->u.dst);
239
240 if (!tp->write_seq)
241 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
242 inet->daddr,
243 inet->sport,
244 usin->sin_port);
245
246 inet->id = tp->write_seq ^ jiffies;
247
248 err = tcp_connect(sk);
249 rt = NULL;
250 if (err)
251 goto failure;
252
253 return 0;
254
255 failure:
256 /*
257 * This unhashes the socket and releases the local port,
258 * if necessary.
259 */
260 tcp_set_state(sk, TCP_CLOSE);
261 ip_rt_put(rt);
262 sk->sk_route_caps = 0;
263 inet->dport = 0;
264 return err;
265 }
266
267 /*
268 * This routine does path mtu discovery as defined in RFC1191.
269 */
270 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
271 {
272 struct dst_entry *dst;
273 struct inet_sock *inet = inet_sk(sk);
274
275 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
276 * send out by Linux are always <576bytes so they should go through
277 * unfragmented).
278 */
279 if (sk->sk_state == TCP_LISTEN)
280 return;
281
282 /* We don't check in the destentry if pmtu discovery is forbidden
283 * on this route. We just assume that no packet_to_big packets
284 * are send back when pmtu discovery is not active.
285 * There is a small race when the user changes this flag in the
286 * route, but I think that's acceptable.
287 */
288 if ((dst = __sk_dst_check(sk, 0)) == NULL)
289 return;
290
291 dst->ops->update_pmtu(dst, mtu);
292
293 /* Something is about to be wrong... Remember soft error
294 * for the case, if this connection will not able to recover.
295 */
296 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
297 sk->sk_err_soft = EMSGSIZE;
298
299 mtu = dst_mtu(dst);
300
301 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
302 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
303 tcp_sync_mss(sk, mtu);
304
305 /* Resend the TCP packet because it's
306 * clear that the old packet has been
307 * dropped. This is the new "fast" path mtu
308 * discovery.
309 */
310 tcp_simple_retransmit(sk);
311 } /* else let the usual retransmit timer handle it */
312 }
313
314 /*
315 * This routine is called by the ICMP module when it gets some
316 * sort of error condition. If err < 0 then the socket should
317 * be closed and the error returned to the user. If err > 0
318 * it's just the icmp type << 8 | icmp code. After adjustment
319 * header points to the first 8 bytes of the tcp header. We need
320 * to find the appropriate port.
321 *
322 * The locking strategy used here is very "optimistic". When
323 * someone else accesses the socket the ICMP is just dropped
324 * and for some paths there is no check at all.
325 * A more general error queue to queue errors for later handling
326 * is probably better.
327 *
328 */
329
330 void tcp_v4_err(struct sk_buff *skb, u32 info)
331 {
332 struct iphdr *iph = (struct iphdr *)skb->data;
333 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
334 struct tcp_sock *tp;
335 struct inet_sock *inet;
336 const int type = icmp_hdr(skb)->type;
337 const int code = icmp_hdr(skb)->code;
338 struct sock *sk;
339 __u32 seq;
340 int err;
341 struct net *net = dev_net(skb->dev);
342
343 if (skb->len < (iph->ihl << 2) + 8) {
344 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
345 return;
346 }
347
348 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
349 iph->saddr, th->source, inet_iif(skb));
350 if (!sk) {
351 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
352 return;
353 }
354 if (sk->sk_state == TCP_TIME_WAIT) {
355 inet_twsk_put(inet_twsk(sk));
356 return;
357 }
358
359 bh_lock_sock(sk);
360 /* If too many ICMPs get dropped on busy
361 * servers this needs to be solved differently.
362 */
363 if (sock_owned_by_user(sk))
364 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
365
366 if (sk->sk_state == TCP_CLOSE)
367 goto out;
368
369 tp = tcp_sk(sk);
370 seq = ntohl(th->seq);
371 if (sk->sk_state != TCP_LISTEN &&
372 !between(seq, tp->snd_una, tp->snd_nxt)) {
373 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
374 goto out;
375 }
376
377 switch (type) {
378 case ICMP_SOURCE_QUENCH:
379 /* Just silently ignore these. */
380 goto out;
381 case ICMP_PARAMETERPROB:
382 err = EPROTO;
383 break;
384 case ICMP_DEST_UNREACH:
385 if (code > NR_ICMP_UNREACH)
386 goto out;
387
388 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
389 if (!sock_owned_by_user(sk))
390 do_pmtu_discovery(sk, iph, info);
391 goto out;
392 }
393
394 err = icmp_err_convert[code].errno;
395 break;
396 case ICMP_TIME_EXCEEDED:
397 err = EHOSTUNREACH;
398 break;
399 default:
400 goto out;
401 }
402
403 switch (sk->sk_state) {
404 struct request_sock *req, **prev;
405 case TCP_LISTEN:
406 if (sock_owned_by_user(sk))
407 goto out;
408
409 req = inet_csk_search_req(sk, &prev, th->dest,
410 iph->daddr, iph->saddr);
411 if (!req)
412 goto out;
413
414 /* ICMPs are not backlogged, hence we cannot get
415 an established socket here.
416 */
417 WARN_ON(req->sk);
418
419 if (seq != tcp_rsk(req)->snt_isn) {
420 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
421 goto out;
422 }
423
424 /*
425 * Still in SYN_RECV, just remove it silently.
426 * There is no good way to pass the error to the newly
427 * created socket, and POSIX does not want network
428 * errors returned from accept().
429 */
430 inet_csk_reqsk_queue_drop(sk, req, prev);
431 goto out;
432
433 case TCP_SYN_SENT:
434 case TCP_SYN_RECV: /* Cannot happen.
435 It can f.e. if SYNs crossed.
436 */
437 if (!sock_owned_by_user(sk)) {
438 sk->sk_err = err;
439
440 sk->sk_error_report(sk);
441
442 tcp_done(sk);
443 } else {
444 sk->sk_err_soft = err;
445 }
446 goto out;
447 }
448
449 /* If we've already connected we will keep trying
450 * until we time out, or the user gives up.
451 *
452 * rfc1122 4.2.3.9 allows to consider as hard errors
453 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
454 * but it is obsoleted by pmtu discovery).
455 *
456 * Note, that in modern internet, where routing is unreliable
457 * and in each dark corner broken firewalls sit, sending random
458 * errors ordered by their masters even this two messages finally lose
459 * their original sense (even Linux sends invalid PORT_UNREACHs)
460 *
461 * Now we are in compliance with RFCs.
462 * --ANK (980905)
463 */
464
465 inet = inet_sk(sk);
466 if (!sock_owned_by_user(sk) && inet->recverr) {
467 sk->sk_err = err;
468 sk->sk_error_report(sk);
469 } else { /* Only an error on timeout */
470 sk->sk_err_soft = err;
471 }
472
473 out:
474 bh_unlock_sock(sk);
475 sock_put(sk);
476 }
477
478 /* This routine computes an IPv4 TCP checksum. */
479 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
480 {
481 struct inet_sock *inet = inet_sk(sk);
482 struct tcphdr *th = tcp_hdr(skb);
483
484 if (skb->ip_summed == CHECKSUM_PARTIAL) {
485 th->check = ~tcp_v4_check(len, inet->saddr,
486 inet->daddr, 0);
487 skb->csum_start = skb_transport_header(skb) - skb->head;
488 skb->csum_offset = offsetof(struct tcphdr, check);
489 } else {
490 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
491 csum_partial(th,
492 th->doff << 2,
493 skb->csum));
494 }
495 }
496
497 int tcp_v4_gso_send_check(struct sk_buff *skb)
498 {
499 const struct iphdr *iph;
500 struct tcphdr *th;
501
502 if (!pskb_may_pull(skb, sizeof(*th)))
503 return -EINVAL;
504
505 iph = ip_hdr(skb);
506 th = tcp_hdr(skb);
507
508 th->check = 0;
509 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
510 skb->csum_start = skb_transport_header(skb) - skb->head;
511 skb->csum_offset = offsetof(struct tcphdr, check);
512 skb->ip_summed = CHECKSUM_PARTIAL;
513 return 0;
514 }
515
516 /*
517 * This routine will send an RST to the other tcp.
518 *
519 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
520 * for reset.
521 * Answer: if a packet caused RST, it is not for a socket
522 * existing in our system, if it is matched to a socket,
523 * it is just duplicate segment or bug in other side's TCP.
524 * So that we build reply only basing on parameters
525 * arrived with segment.
526 * Exception: precedence violation. We do not implement it in any case.
527 */
528
529 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
530 {
531 struct tcphdr *th = tcp_hdr(skb);
532 struct {
533 struct tcphdr th;
534 #ifdef CONFIG_TCP_MD5SIG
535 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
536 #endif
537 } rep;
538 struct ip_reply_arg arg;
539 #ifdef CONFIG_TCP_MD5SIG
540 struct tcp_md5sig_key *key;
541 #endif
542 struct net *net;
543
544 /* Never send a reset in response to a reset. */
545 if (th->rst)
546 return;
547
548 if (skb->rtable->rt_type != RTN_LOCAL)
549 return;
550
551 /* Swap the send and the receive. */
552 memset(&rep, 0, sizeof(rep));
553 rep.th.dest = th->source;
554 rep.th.source = th->dest;
555 rep.th.doff = sizeof(struct tcphdr) / 4;
556 rep.th.rst = 1;
557
558 if (th->ack) {
559 rep.th.seq = th->ack_seq;
560 } else {
561 rep.th.ack = 1;
562 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
563 skb->len - (th->doff << 2));
564 }
565
566 memset(&arg, 0, sizeof(arg));
567 arg.iov[0].iov_base = (unsigned char *)&rep;
568 arg.iov[0].iov_len = sizeof(rep.th);
569
570 #ifdef CONFIG_TCP_MD5SIG
571 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
572 if (key) {
573 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
574 (TCPOPT_NOP << 16) |
575 (TCPOPT_MD5SIG << 8) |
576 TCPOLEN_MD5SIG);
577 /* Update length and the length the header thinks exists */
578 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
579 rep.th.doff = arg.iov[0].iov_len / 4;
580
581 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
582 key, ip_hdr(skb)->saddr,
583 ip_hdr(skb)->daddr, &rep.th);
584 }
585 #endif
586 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
587 ip_hdr(skb)->saddr, /* XXX */
588 arg.iov[0].iov_len, IPPROTO_TCP, 0);
589 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
590 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
591
592 net = dev_net(skb->dst->dev);
593 ip_send_reply(net->ipv4.tcp_sock, skb,
594 &arg, arg.iov[0].iov_len);
595
596 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
597 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
598 }
599
600 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
601 outside socket context is ugly, certainly. What can I do?
602 */
603
604 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
605 u32 win, u32 ts, int oif,
606 struct tcp_md5sig_key *key,
607 int reply_flags)
608 {
609 struct tcphdr *th = tcp_hdr(skb);
610 struct {
611 struct tcphdr th;
612 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
613 #ifdef CONFIG_TCP_MD5SIG
614 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
615 #endif
616 ];
617 } rep;
618 struct ip_reply_arg arg;
619 struct net *net = dev_net(skb->dst->dev);
620
621 memset(&rep.th, 0, sizeof(struct tcphdr));
622 memset(&arg, 0, sizeof(arg));
623
624 arg.iov[0].iov_base = (unsigned char *)&rep;
625 arg.iov[0].iov_len = sizeof(rep.th);
626 if (ts) {
627 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
628 (TCPOPT_TIMESTAMP << 8) |
629 TCPOLEN_TIMESTAMP);
630 rep.opt[1] = htonl(tcp_time_stamp);
631 rep.opt[2] = htonl(ts);
632 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
633 }
634
635 /* Swap the send and the receive. */
636 rep.th.dest = th->source;
637 rep.th.source = th->dest;
638 rep.th.doff = arg.iov[0].iov_len / 4;
639 rep.th.seq = htonl(seq);
640 rep.th.ack_seq = htonl(ack);
641 rep.th.ack = 1;
642 rep.th.window = htons(win);
643
644 #ifdef CONFIG_TCP_MD5SIG
645 if (key) {
646 int offset = (ts) ? 3 : 0;
647
648 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
649 (TCPOPT_NOP << 16) |
650 (TCPOPT_MD5SIG << 8) |
651 TCPOLEN_MD5SIG);
652 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
653 rep.th.doff = arg.iov[0].iov_len/4;
654
655 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
656 key, ip_hdr(skb)->saddr,
657 ip_hdr(skb)->daddr, &rep.th);
658 }
659 #endif
660 arg.flags = reply_flags;
661 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
662 ip_hdr(skb)->saddr, /* XXX */
663 arg.iov[0].iov_len, IPPROTO_TCP, 0);
664 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
665 if (oif)
666 arg.bound_dev_if = oif;
667
668 ip_send_reply(net->ipv4.tcp_sock, skb,
669 &arg, arg.iov[0].iov_len);
670
671 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
672 }
673
674 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
675 {
676 struct inet_timewait_sock *tw = inet_twsk(sk);
677 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
678
679 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
680 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
681 tcptw->tw_ts_recent,
682 tw->tw_bound_dev_if,
683 tcp_twsk_md5_key(tcptw),
684 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
685 );
686
687 inet_twsk_put(tw);
688 }
689
690 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
691 struct request_sock *req)
692 {
693 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
694 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
695 req->ts_recent,
696 0,
697 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
698 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
699 }
700
701 /*
702 * Send a SYN-ACK after having received a SYN.
703 * This still operates on a request_sock only, not on a big
704 * socket.
705 */
706 static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
707 struct dst_entry *dst)
708 {
709 const struct inet_request_sock *ireq = inet_rsk(req);
710 int err = -1;
711 struct sk_buff * skb;
712
713 /* First, grab a route. */
714 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
715 return -1;
716
717 skb = tcp_make_synack(sk, dst, req);
718
719 if (skb) {
720 struct tcphdr *th = tcp_hdr(skb);
721
722 th->check = tcp_v4_check(skb->len,
723 ireq->loc_addr,
724 ireq->rmt_addr,
725 csum_partial(th, skb->len,
726 skb->csum));
727
728 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
729 ireq->rmt_addr,
730 ireq->opt);
731 err = net_xmit_eval(err);
732 }
733
734 dst_release(dst);
735 return err;
736 }
737
738 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
739 {
740 return __tcp_v4_send_synack(sk, req, NULL);
741 }
742
743 /*
744 * IPv4 request_sock destructor.
745 */
746 static void tcp_v4_reqsk_destructor(struct request_sock *req)
747 {
748 kfree(inet_rsk(req)->opt);
749 }
750
751 #ifdef CONFIG_SYN_COOKIES
752 static void syn_flood_warning(struct sk_buff *skb)
753 {
754 static unsigned long warntime;
755
756 if (time_after(jiffies, (warntime + HZ * 60))) {
757 warntime = jiffies;
758 printk(KERN_INFO
759 "possible SYN flooding on port %d. Sending cookies.\n",
760 ntohs(tcp_hdr(skb)->dest));
761 }
762 }
763 #endif
764
765 /*
766 * Save and compile IPv4 options into the request_sock if needed.
767 */
768 static struct ip_options *tcp_v4_save_options(struct sock *sk,
769 struct sk_buff *skb)
770 {
771 struct ip_options *opt = &(IPCB(skb)->opt);
772 struct ip_options *dopt = NULL;
773
774 if (opt && opt->optlen) {
775 int opt_size = optlength(opt);
776 dopt = kmalloc(opt_size, GFP_ATOMIC);
777 if (dopt) {
778 if (ip_options_echo(dopt, skb)) {
779 kfree(dopt);
780 dopt = NULL;
781 }
782 }
783 }
784 return dopt;
785 }
786
787 #ifdef CONFIG_TCP_MD5SIG
788 /*
789 * RFC2385 MD5 checksumming requires a mapping of
790 * IP address->MD5 Key.
791 * We need to maintain these in the sk structure.
792 */
793
794 /* Find the Key structure for an address. */
795 static struct tcp_md5sig_key *
796 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
797 {
798 struct tcp_sock *tp = tcp_sk(sk);
799 int i;
800
801 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
802 return NULL;
803 for (i = 0; i < tp->md5sig_info->entries4; i++) {
804 if (tp->md5sig_info->keys4[i].addr == addr)
805 return &tp->md5sig_info->keys4[i].base;
806 }
807 return NULL;
808 }
809
810 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
811 struct sock *addr_sk)
812 {
813 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
814 }
815
816 EXPORT_SYMBOL(tcp_v4_md5_lookup);
817
818 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
819 struct request_sock *req)
820 {
821 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
822 }
823
824 /* This can be called on a newly created socket, from other files */
825 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
826 u8 *newkey, u8 newkeylen)
827 {
828 /* Add Key to the list */
829 struct tcp_md5sig_key *key;
830 struct tcp_sock *tp = tcp_sk(sk);
831 struct tcp4_md5sig_key *keys;
832
833 key = tcp_v4_md5_do_lookup(sk, addr);
834 if (key) {
835 /* Pre-existing entry - just update that one. */
836 kfree(key->key);
837 key->key = newkey;
838 key->keylen = newkeylen;
839 } else {
840 struct tcp_md5sig_info *md5sig;
841
842 if (!tp->md5sig_info) {
843 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
844 GFP_ATOMIC);
845 if (!tp->md5sig_info) {
846 kfree(newkey);
847 return -ENOMEM;
848 }
849 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
850 }
851 if (tcp_alloc_md5sig_pool() == NULL) {
852 kfree(newkey);
853 return -ENOMEM;
854 }
855 md5sig = tp->md5sig_info;
856
857 if (md5sig->alloced4 == md5sig->entries4) {
858 keys = kmalloc((sizeof(*keys) *
859 (md5sig->entries4 + 1)), GFP_ATOMIC);
860 if (!keys) {
861 kfree(newkey);
862 tcp_free_md5sig_pool();
863 return -ENOMEM;
864 }
865
866 if (md5sig->entries4)
867 memcpy(keys, md5sig->keys4,
868 sizeof(*keys) * md5sig->entries4);
869
870 /* Free old key list, and reference new one */
871 kfree(md5sig->keys4);
872 md5sig->keys4 = keys;
873 md5sig->alloced4++;
874 }
875 md5sig->entries4++;
876 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
877 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
878 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
879 }
880 return 0;
881 }
882
883 EXPORT_SYMBOL(tcp_v4_md5_do_add);
884
885 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
886 u8 *newkey, u8 newkeylen)
887 {
888 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
889 newkey, newkeylen);
890 }
891
892 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
893 {
894 struct tcp_sock *tp = tcp_sk(sk);
895 int i;
896
897 for (i = 0; i < tp->md5sig_info->entries4; i++) {
898 if (tp->md5sig_info->keys4[i].addr == addr) {
899 /* Free the key */
900 kfree(tp->md5sig_info->keys4[i].base.key);
901 tp->md5sig_info->entries4--;
902
903 if (tp->md5sig_info->entries4 == 0) {
904 kfree(tp->md5sig_info->keys4);
905 tp->md5sig_info->keys4 = NULL;
906 tp->md5sig_info->alloced4 = 0;
907 } else if (tp->md5sig_info->entries4 != i) {
908 /* Need to do some manipulation */
909 memmove(&tp->md5sig_info->keys4[i],
910 &tp->md5sig_info->keys4[i+1],
911 (tp->md5sig_info->entries4 - i) *
912 sizeof(struct tcp4_md5sig_key));
913 }
914 tcp_free_md5sig_pool();
915 return 0;
916 }
917 }
918 return -ENOENT;
919 }
920
921 EXPORT_SYMBOL(tcp_v4_md5_do_del);
922
923 static void tcp_v4_clear_md5_list(struct sock *sk)
924 {
925 struct tcp_sock *tp = tcp_sk(sk);
926
927 /* Free each key, then the set of key keys,
928 * the crypto element, and then decrement our
929 * hold on the last resort crypto.
930 */
931 if (tp->md5sig_info->entries4) {
932 int i;
933 for (i = 0; i < tp->md5sig_info->entries4; i++)
934 kfree(tp->md5sig_info->keys4[i].base.key);
935 tp->md5sig_info->entries4 = 0;
936 tcp_free_md5sig_pool();
937 }
938 if (tp->md5sig_info->keys4) {
939 kfree(tp->md5sig_info->keys4);
940 tp->md5sig_info->keys4 = NULL;
941 tp->md5sig_info->alloced4 = 0;
942 }
943 }
944
945 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
946 int optlen)
947 {
948 struct tcp_md5sig cmd;
949 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
950 u8 *newkey;
951
952 if (optlen < sizeof(cmd))
953 return -EINVAL;
954
955 if (copy_from_user(&cmd, optval, sizeof(cmd)))
956 return -EFAULT;
957
958 if (sin->sin_family != AF_INET)
959 return -EINVAL;
960
961 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
962 if (!tcp_sk(sk)->md5sig_info)
963 return -ENOENT;
964 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
965 }
966
967 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
968 return -EINVAL;
969
970 if (!tcp_sk(sk)->md5sig_info) {
971 struct tcp_sock *tp = tcp_sk(sk);
972 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
973
974 if (!p)
975 return -EINVAL;
976
977 tp->md5sig_info = p;
978 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
979 }
980
981 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
982 if (!newkey)
983 return -ENOMEM;
984 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
985 newkey, cmd.tcpm_keylen);
986 }
987
988 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
989 __be32 daddr, __be32 saddr, int nbytes)
990 {
991 struct tcp4_pseudohdr *bp;
992 struct scatterlist sg;
993
994 bp = &hp->md5_blk.ip4;
995
996 /*
997 * 1. the TCP pseudo-header (in the order: source IP address,
998 * destination IP address, zero-padded protocol number, and
999 * segment length)
1000 */
1001 bp->saddr = saddr;
1002 bp->daddr = daddr;
1003 bp->pad = 0;
1004 bp->protocol = IPPROTO_TCP;
1005 bp->len = cpu_to_be16(nbytes);
1006
1007 sg_init_one(&sg, bp, sizeof(*bp));
1008 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1009 }
1010
1011 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1012 __be32 daddr, __be32 saddr, struct tcphdr *th)
1013 {
1014 struct tcp_md5sig_pool *hp;
1015 struct hash_desc *desc;
1016
1017 hp = tcp_get_md5sig_pool();
1018 if (!hp)
1019 goto clear_hash_noput;
1020 desc = &hp->md5_desc;
1021
1022 if (crypto_hash_init(desc))
1023 goto clear_hash;
1024 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1025 goto clear_hash;
1026 if (tcp_md5_hash_header(hp, th))
1027 goto clear_hash;
1028 if (tcp_md5_hash_key(hp, key))
1029 goto clear_hash;
1030 if (crypto_hash_final(desc, md5_hash))
1031 goto clear_hash;
1032
1033 tcp_put_md5sig_pool();
1034 return 0;
1035
1036 clear_hash:
1037 tcp_put_md5sig_pool();
1038 clear_hash_noput:
1039 memset(md5_hash, 0, 16);
1040 return 1;
1041 }
1042
1043 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1044 struct sock *sk, struct request_sock *req,
1045 struct sk_buff *skb)
1046 {
1047 struct tcp_md5sig_pool *hp;
1048 struct hash_desc *desc;
1049 struct tcphdr *th = tcp_hdr(skb);
1050 __be32 saddr, daddr;
1051
1052 if (sk) {
1053 saddr = inet_sk(sk)->saddr;
1054 daddr = inet_sk(sk)->daddr;
1055 } else if (req) {
1056 saddr = inet_rsk(req)->loc_addr;
1057 daddr = inet_rsk(req)->rmt_addr;
1058 } else {
1059 const struct iphdr *iph = ip_hdr(skb);
1060 saddr = iph->saddr;
1061 daddr = iph->daddr;
1062 }
1063
1064 hp = tcp_get_md5sig_pool();
1065 if (!hp)
1066 goto clear_hash_noput;
1067 desc = &hp->md5_desc;
1068
1069 if (crypto_hash_init(desc))
1070 goto clear_hash;
1071
1072 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1073 goto clear_hash;
1074 if (tcp_md5_hash_header(hp, th))
1075 goto clear_hash;
1076 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1077 goto clear_hash;
1078 if (tcp_md5_hash_key(hp, key))
1079 goto clear_hash;
1080 if (crypto_hash_final(desc, md5_hash))
1081 goto clear_hash;
1082
1083 tcp_put_md5sig_pool();
1084 return 0;
1085
1086 clear_hash:
1087 tcp_put_md5sig_pool();
1088 clear_hash_noput:
1089 memset(md5_hash, 0, 16);
1090 return 1;
1091 }
1092
1093 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1094
1095 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1096 {
1097 /*
1098 * This gets called for each TCP segment that arrives
1099 * so we want to be efficient.
1100 * We have 3 drop cases:
1101 * o No MD5 hash and one expected.
1102 * o MD5 hash and we're not expecting one.
1103 * o MD5 hash and its wrong.
1104 */
1105 __u8 *hash_location = NULL;
1106 struct tcp_md5sig_key *hash_expected;
1107 const struct iphdr *iph = ip_hdr(skb);
1108 struct tcphdr *th = tcp_hdr(skb);
1109 int genhash;
1110 unsigned char newhash[16];
1111
1112 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1113 hash_location = tcp_parse_md5sig_option(th);
1114
1115 /* We've parsed the options - do we have a hash? */
1116 if (!hash_expected && !hash_location)
1117 return 0;
1118
1119 if (hash_expected && !hash_location) {
1120 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1121 return 1;
1122 }
1123
1124 if (!hash_expected && hash_location) {
1125 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1126 return 1;
1127 }
1128
1129 /* Okay, so this is hash_expected and hash_location -
1130 * so we need to calculate the checksum.
1131 */
1132 genhash = tcp_v4_md5_hash_skb(newhash,
1133 hash_expected,
1134 NULL, NULL, skb);
1135
1136 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1137 if (net_ratelimit()) {
1138 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1139 &iph->saddr, ntohs(th->source),
1140 &iph->daddr, ntohs(th->dest),
1141 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1142 }
1143 return 1;
1144 }
1145 return 0;
1146 }
1147
1148 #endif
1149
1150 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1151 .family = PF_INET,
1152 .obj_size = sizeof(struct tcp_request_sock),
1153 .rtx_syn_ack = tcp_v4_send_synack,
1154 .send_ack = tcp_v4_reqsk_send_ack,
1155 .destructor = tcp_v4_reqsk_destructor,
1156 .send_reset = tcp_v4_send_reset,
1157 };
1158
1159 #ifdef CONFIG_TCP_MD5SIG
1160 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1161 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1162 };
1163 #endif
1164
1165 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1166 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1167 .twsk_unique = tcp_twsk_unique,
1168 .twsk_destructor= tcp_twsk_destructor,
1169 };
1170
1171 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1172 {
1173 struct inet_request_sock *ireq;
1174 struct tcp_options_received tmp_opt;
1175 struct request_sock *req;
1176 __be32 saddr = ip_hdr(skb)->saddr;
1177 __be32 daddr = ip_hdr(skb)->daddr;
1178 __u32 isn = TCP_SKB_CB(skb)->when;
1179 struct dst_entry *dst = NULL;
1180 #ifdef CONFIG_SYN_COOKIES
1181 int want_cookie = 0;
1182 #else
1183 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1184 #endif
1185
1186 /* Never answer to SYNs send to broadcast or multicast */
1187 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1188 goto drop;
1189
1190 /* TW buckets are converted to open requests without
1191 * limitations, they conserve resources and peer is
1192 * evidently real one.
1193 */
1194 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1195 #ifdef CONFIG_SYN_COOKIES
1196 if (sysctl_tcp_syncookies) {
1197 want_cookie = 1;
1198 } else
1199 #endif
1200 goto drop;
1201 }
1202
1203 /* Accept backlog is full. If we have already queued enough
1204 * of warm entries in syn queue, drop request. It is better than
1205 * clogging syn queue with openreqs with exponentially increasing
1206 * timeout.
1207 */
1208 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1209 goto drop;
1210
1211 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1212 if (!req)
1213 goto drop;
1214
1215 #ifdef CONFIG_TCP_MD5SIG
1216 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1217 #endif
1218
1219 tcp_clear_options(&tmp_opt);
1220 tmp_opt.mss_clamp = 536;
1221 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1222
1223 tcp_parse_options(skb, &tmp_opt, 0);
1224
1225 if (want_cookie && !tmp_opt.saw_tstamp)
1226 tcp_clear_options(&tmp_opt);
1227
1228 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1229 /* Some OSes (unknown ones, but I see them on web server, which
1230 * contains information interesting only for windows'
1231 * users) do not send their stamp in SYN. It is easy case.
1232 * We simply do not advertise TS support.
1233 */
1234 tmp_opt.saw_tstamp = 0;
1235 tmp_opt.tstamp_ok = 0;
1236 }
1237 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1238
1239 tcp_openreq_init(req, &tmp_opt, skb);
1240
1241 if (security_inet_conn_request(sk, skb, req))
1242 goto drop_and_free;
1243
1244 ireq = inet_rsk(req);
1245 ireq->loc_addr = daddr;
1246 ireq->rmt_addr = saddr;
1247 ireq->no_srccheck = inet_sk(sk)->transparent;
1248 ireq->opt = tcp_v4_save_options(sk, skb);
1249 if (!want_cookie)
1250 TCP_ECN_create_request(req, tcp_hdr(skb));
1251
1252 if (want_cookie) {
1253 #ifdef CONFIG_SYN_COOKIES
1254 syn_flood_warning(skb);
1255 req->cookie_ts = tmp_opt.tstamp_ok;
1256 #endif
1257 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1258 } else if (!isn) {
1259 struct inet_peer *peer = NULL;
1260
1261 /* VJ's idea. We save last timestamp seen
1262 * from the destination in peer table, when entering
1263 * state TIME-WAIT, and check against it before
1264 * accepting new connection request.
1265 *
1266 * If "isn" is not zero, this request hit alive
1267 * timewait bucket, so that all the necessary checks
1268 * are made in the function processing timewait state.
1269 */
1270 if (tmp_opt.saw_tstamp &&
1271 tcp_death_row.sysctl_tw_recycle &&
1272 (dst = inet_csk_route_req(sk, req)) != NULL &&
1273 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1274 peer->v4daddr == saddr) {
1275 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1276 (s32)(peer->tcp_ts - req->ts_recent) >
1277 TCP_PAWS_WINDOW) {
1278 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1279 goto drop_and_release;
1280 }
1281 }
1282 /* Kill the following clause, if you dislike this way. */
1283 else if (!sysctl_tcp_syncookies &&
1284 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1285 (sysctl_max_syn_backlog >> 2)) &&
1286 (!peer || !peer->tcp_ts_stamp) &&
1287 (!dst || !dst_metric(dst, RTAX_RTT))) {
1288 /* Without syncookies last quarter of
1289 * backlog is filled with destinations,
1290 * proven to be alive.
1291 * It means that we continue to communicate
1292 * to destinations, already remembered
1293 * to the moment of synflood.
1294 */
1295 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1296 &saddr, ntohs(tcp_hdr(skb)->source));
1297 goto drop_and_release;
1298 }
1299
1300 isn = tcp_v4_init_sequence(skb);
1301 }
1302 tcp_rsk(req)->snt_isn = isn;
1303
1304 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1305 goto drop_and_free;
1306
1307 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1308 return 0;
1309
1310 drop_and_release:
1311 dst_release(dst);
1312 drop_and_free:
1313 reqsk_free(req);
1314 drop:
1315 return 0;
1316 }
1317
1318
1319 /*
1320 * The three way handshake has completed - we got a valid synack -
1321 * now create the new socket.
1322 */
1323 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1324 struct request_sock *req,
1325 struct dst_entry *dst)
1326 {
1327 struct inet_request_sock *ireq;
1328 struct inet_sock *newinet;
1329 struct tcp_sock *newtp;
1330 struct sock *newsk;
1331 #ifdef CONFIG_TCP_MD5SIG
1332 struct tcp_md5sig_key *key;
1333 #endif
1334
1335 if (sk_acceptq_is_full(sk))
1336 goto exit_overflow;
1337
1338 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1339 goto exit;
1340
1341 newsk = tcp_create_openreq_child(sk, req, skb);
1342 if (!newsk)
1343 goto exit;
1344
1345 newsk->sk_gso_type = SKB_GSO_TCPV4;
1346 sk_setup_caps(newsk, dst);
1347
1348 newtp = tcp_sk(newsk);
1349 newinet = inet_sk(newsk);
1350 ireq = inet_rsk(req);
1351 newinet->daddr = ireq->rmt_addr;
1352 newinet->rcv_saddr = ireq->loc_addr;
1353 newinet->saddr = ireq->loc_addr;
1354 newinet->opt = ireq->opt;
1355 ireq->opt = NULL;
1356 newinet->mc_index = inet_iif(skb);
1357 newinet->mc_ttl = ip_hdr(skb)->ttl;
1358 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1359 if (newinet->opt)
1360 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1361 newinet->id = newtp->write_seq ^ jiffies;
1362
1363 tcp_mtup_init(newsk);
1364 tcp_sync_mss(newsk, dst_mtu(dst));
1365 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1366 if (tcp_sk(sk)->rx_opt.user_mss &&
1367 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1368 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1369
1370 tcp_initialize_rcv_mss(newsk);
1371
1372 #ifdef CONFIG_TCP_MD5SIG
1373 /* Copy over the MD5 key from the original socket */
1374 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1375 /*
1376 * We're using one, so create a matching key
1377 * on the newsk structure. If we fail to get
1378 * memory, then we end up not copying the key
1379 * across. Shucks.
1380 */
1381 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1382 if (newkey != NULL)
1383 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1384 newkey, key->keylen);
1385 newsk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1386 }
1387 #endif
1388
1389 __inet_hash_nolisten(newsk);
1390 __inet_inherit_port(sk, newsk);
1391
1392 return newsk;
1393
1394 exit_overflow:
1395 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1396 exit:
1397 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1398 dst_release(dst);
1399 return NULL;
1400 }
1401
1402 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1403 {
1404 struct tcphdr *th = tcp_hdr(skb);
1405 const struct iphdr *iph = ip_hdr(skb);
1406 struct sock *nsk;
1407 struct request_sock **prev;
1408 /* Find possible connection requests. */
1409 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1410 iph->saddr, iph->daddr);
1411 if (req)
1412 return tcp_check_req(sk, skb, req, prev);
1413
1414 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1415 th->source, iph->daddr, th->dest, inet_iif(skb));
1416
1417 if (nsk) {
1418 if (nsk->sk_state != TCP_TIME_WAIT) {
1419 bh_lock_sock(nsk);
1420 return nsk;
1421 }
1422 inet_twsk_put(inet_twsk(nsk));
1423 return NULL;
1424 }
1425
1426 #ifdef CONFIG_SYN_COOKIES
1427 if (!th->rst && !th->syn && th->ack)
1428 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1429 #endif
1430 return sk;
1431 }
1432
1433 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1434 {
1435 const struct iphdr *iph = ip_hdr(skb);
1436
1437 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1438 if (!tcp_v4_check(skb->len, iph->saddr,
1439 iph->daddr, skb->csum)) {
1440 skb->ip_summed = CHECKSUM_UNNECESSARY;
1441 return 0;
1442 }
1443 }
1444
1445 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1446 skb->len, IPPROTO_TCP, 0);
1447
1448 if (skb->len <= 76) {
1449 return __skb_checksum_complete(skb);
1450 }
1451 return 0;
1452 }
1453
1454
1455 /* The socket must have it's spinlock held when we get
1456 * here.
1457 *
1458 * We have a potential double-lock case here, so even when
1459 * doing backlog processing we use the BH locking scheme.
1460 * This is because we cannot sleep with the original spinlock
1461 * held.
1462 */
1463 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1464 {
1465 struct sock *rsk;
1466 #ifdef CONFIG_TCP_MD5SIG
1467 /*
1468 * We really want to reject the packet as early as possible
1469 * if:
1470 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1471 * o There is an MD5 option and we're not expecting one
1472 */
1473 if (tcp_v4_inbound_md5_hash(sk, skb))
1474 goto discard;
1475 #endif
1476
1477 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1478 TCP_CHECK_TIMER(sk);
1479 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1480 rsk = sk;
1481 goto reset;
1482 }
1483 TCP_CHECK_TIMER(sk);
1484 return 0;
1485 }
1486
1487 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1488 goto csum_err;
1489
1490 if (sk->sk_state == TCP_LISTEN) {
1491 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1492 if (!nsk)
1493 goto discard;
1494
1495 if (nsk != sk) {
1496 if (tcp_child_process(sk, nsk, skb)) {
1497 rsk = nsk;
1498 goto reset;
1499 }
1500 return 0;
1501 }
1502 }
1503
1504 TCP_CHECK_TIMER(sk);
1505 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1506 rsk = sk;
1507 goto reset;
1508 }
1509 TCP_CHECK_TIMER(sk);
1510 return 0;
1511
1512 reset:
1513 tcp_v4_send_reset(rsk, skb);
1514 discard:
1515 kfree_skb(skb);
1516 /* Be careful here. If this function gets more complicated and
1517 * gcc suffers from register pressure on the x86, sk (in %ebx)
1518 * might be destroyed here. This current version compiles correctly,
1519 * but you have been warned.
1520 */
1521 return 0;
1522
1523 csum_err:
1524 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1525 goto discard;
1526 }
1527
1528 /*
1529 * From tcp_input.c
1530 */
1531
1532 int tcp_v4_rcv(struct sk_buff *skb)
1533 {
1534 const struct iphdr *iph;
1535 struct tcphdr *th;
1536 struct sock *sk;
1537 int ret;
1538 struct net *net = dev_net(skb->dev);
1539
1540 if (skb->pkt_type != PACKET_HOST)
1541 goto discard_it;
1542
1543 /* Count it even if it's bad */
1544 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1545
1546 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1547 goto discard_it;
1548
1549 th = tcp_hdr(skb);
1550
1551 if (th->doff < sizeof(struct tcphdr) / 4)
1552 goto bad_packet;
1553 if (!pskb_may_pull(skb, th->doff * 4))
1554 goto discard_it;
1555
1556 /* An explanation is required here, I think.
1557 * Packet length and doff are validated by header prediction,
1558 * provided case of th->doff==0 is eliminated.
1559 * So, we defer the checks. */
1560 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1561 goto bad_packet;
1562
1563 th = tcp_hdr(skb);
1564 iph = ip_hdr(skb);
1565 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1566 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1567 skb->len - th->doff * 4);
1568 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1569 TCP_SKB_CB(skb)->when = 0;
1570 TCP_SKB_CB(skb)->flags = iph->tos;
1571 TCP_SKB_CB(skb)->sacked = 0;
1572
1573 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1574 if (!sk)
1575 goto no_tcp_socket;
1576
1577 process:
1578 if (sk->sk_state == TCP_TIME_WAIT)
1579 goto do_time_wait;
1580
1581 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1582 goto discard_and_relse;
1583 nf_reset(skb);
1584
1585 if (sk_filter(sk, skb))
1586 goto discard_and_relse;
1587
1588 skb->dev = NULL;
1589
1590 bh_lock_sock_nested(sk);
1591 ret = 0;
1592 if (!sock_owned_by_user(sk)) {
1593 #ifdef CONFIG_NET_DMA
1594 struct tcp_sock *tp = tcp_sk(sk);
1595 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1596 tp->ucopy.dma_chan = get_softnet_dma();
1597 if (tp->ucopy.dma_chan)
1598 ret = tcp_v4_do_rcv(sk, skb);
1599 else
1600 #endif
1601 {
1602 if (!tcp_prequeue(sk, skb))
1603 ret = tcp_v4_do_rcv(sk, skb);
1604 }
1605 } else
1606 sk_add_backlog(sk, skb);
1607 bh_unlock_sock(sk);
1608
1609 sock_put(sk);
1610
1611 return ret;
1612
1613 no_tcp_socket:
1614 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1615 goto discard_it;
1616
1617 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1618 bad_packet:
1619 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1620 } else {
1621 tcp_v4_send_reset(NULL, skb);
1622 }
1623
1624 discard_it:
1625 /* Discard frame. */
1626 kfree_skb(skb);
1627 return 0;
1628
1629 discard_and_relse:
1630 sock_put(sk);
1631 goto discard_it;
1632
1633 do_time_wait:
1634 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1635 inet_twsk_put(inet_twsk(sk));
1636 goto discard_it;
1637 }
1638
1639 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1640 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1641 inet_twsk_put(inet_twsk(sk));
1642 goto discard_it;
1643 }
1644 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1645 case TCP_TW_SYN: {
1646 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1647 &tcp_hashinfo,
1648 iph->daddr, th->dest,
1649 inet_iif(skb));
1650 if (sk2) {
1651 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1652 inet_twsk_put(inet_twsk(sk));
1653 sk = sk2;
1654 goto process;
1655 }
1656 /* Fall through to ACK */
1657 }
1658 case TCP_TW_ACK:
1659 tcp_v4_timewait_ack(sk, skb);
1660 break;
1661 case TCP_TW_RST:
1662 goto no_tcp_socket;
1663 case TCP_TW_SUCCESS:;
1664 }
1665 goto discard_it;
1666 }
1667
1668 /* VJ's idea. Save last timestamp seen from this destination
1669 * and hold it at least for normal timewait interval to use for duplicate
1670 * segment detection in subsequent connections, before they enter synchronized
1671 * state.
1672 */
1673
1674 int tcp_v4_remember_stamp(struct sock *sk)
1675 {
1676 struct inet_sock *inet = inet_sk(sk);
1677 struct tcp_sock *tp = tcp_sk(sk);
1678 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1679 struct inet_peer *peer = NULL;
1680 int release_it = 0;
1681
1682 if (!rt || rt->rt_dst != inet->daddr) {
1683 peer = inet_getpeer(inet->daddr, 1);
1684 release_it = 1;
1685 } else {
1686 if (!rt->peer)
1687 rt_bind_peer(rt, 1);
1688 peer = rt->peer;
1689 }
1690
1691 if (peer) {
1692 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1693 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1694 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1695 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1696 peer->tcp_ts = tp->rx_opt.ts_recent;
1697 }
1698 if (release_it)
1699 inet_putpeer(peer);
1700 return 1;
1701 }
1702
1703 return 0;
1704 }
1705
1706 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1707 {
1708 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1709
1710 if (peer) {
1711 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1712
1713 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1714 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1715 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1716 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1717 peer->tcp_ts = tcptw->tw_ts_recent;
1718 }
1719 inet_putpeer(peer);
1720 return 1;
1721 }
1722
1723 return 0;
1724 }
1725
1726 struct inet_connection_sock_af_ops ipv4_specific = {
1727 .queue_xmit = ip_queue_xmit,
1728 .send_check = tcp_v4_send_check,
1729 .rebuild_header = inet_sk_rebuild_header,
1730 .conn_request = tcp_v4_conn_request,
1731 .syn_recv_sock = tcp_v4_syn_recv_sock,
1732 .remember_stamp = tcp_v4_remember_stamp,
1733 .net_header_len = sizeof(struct iphdr),
1734 .setsockopt = ip_setsockopt,
1735 .getsockopt = ip_getsockopt,
1736 .addr2sockaddr = inet_csk_addr2sockaddr,
1737 .sockaddr_len = sizeof(struct sockaddr_in),
1738 .bind_conflict = inet_csk_bind_conflict,
1739 #ifdef CONFIG_COMPAT
1740 .compat_setsockopt = compat_ip_setsockopt,
1741 .compat_getsockopt = compat_ip_getsockopt,
1742 #endif
1743 };
1744
1745 #ifdef CONFIG_TCP_MD5SIG
1746 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1747 .md5_lookup = tcp_v4_md5_lookup,
1748 .calc_md5_hash = tcp_v4_md5_hash_skb,
1749 .md5_add = tcp_v4_md5_add_func,
1750 .md5_parse = tcp_v4_parse_md5_keys,
1751 };
1752 #endif
1753
1754 /* NOTE: A lot of things set to zero explicitly by call to
1755 * sk_alloc() so need not be done here.
1756 */
1757 static int tcp_v4_init_sock(struct sock *sk)
1758 {
1759 struct inet_connection_sock *icsk = inet_csk(sk);
1760 struct tcp_sock *tp = tcp_sk(sk);
1761
1762 skb_queue_head_init(&tp->out_of_order_queue);
1763 tcp_init_xmit_timers(sk);
1764 tcp_prequeue_init(tp);
1765
1766 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1767 tp->mdev = TCP_TIMEOUT_INIT;
1768
1769 /* So many TCP implementations out there (incorrectly) count the
1770 * initial SYN frame in their delayed-ACK and congestion control
1771 * algorithms that we must have the following bandaid to talk
1772 * efficiently to them. -DaveM
1773 */
1774 tp->snd_cwnd = 2;
1775
1776 /* See draft-stevens-tcpca-spec-01 for discussion of the
1777 * initialization of these values.
1778 */
1779 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1780 tp->snd_cwnd_clamp = ~0;
1781 tp->mss_cache = 536;
1782
1783 tp->reordering = sysctl_tcp_reordering;
1784 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1785
1786 sk->sk_state = TCP_CLOSE;
1787
1788 sk->sk_write_space = sk_stream_write_space;
1789 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1790
1791 icsk->icsk_af_ops = &ipv4_specific;
1792 icsk->icsk_sync_mss = tcp_sync_mss;
1793 #ifdef CONFIG_TCP_MD5SIG
1794 tp->af_specific = &tcp_sock_ipv4_specific;
1795 #endif
1796
1797 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1798 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1799
1800 percpu_counter_inc(&tcp_sockets_allocated);
1801
1802 return 0;
1803 }
1804
1805 void tcp_v4_destroy_sock(struct sock *sk)
1806 {
1807 struct tcp_sock *tp = tcp_sk(sk);
1808
1809 tcp_clear_xmit_timers(sk);
1810
1811 tcp_cleanup_congestion_control(sk);
1812
1813 /* Cleanup up the write buffer. */
1814 tcp_write_queue_purge(sk);
1815
1816 /* Cleans up our, hopefully empty, out_of_order_queue. */
1817 __skb_queue_purge(&tp->out_of_order_queue);
1818
1819 #ifdef CONFIG_TCP_MD5SIG
1820 /* Clean up the MD5 key list, if any */
1821 if (tp->md5sig_info) {
1822 tcp_v4_clear_md5_list(sk);
1823 kfree(tp->md5sig_info);
1824 tp->md5sig_info = NULL;
1825 }
1826 #endif
1827
1828 #ifdef CONFIG_NET_DMA
1829 /* Cleans up our sk_async_wait_queue */
1830 __skb_queue_purge(&sk->sk_async_wait_queue);
1831 #endif
1832
1833 /* Clean prequeue, it must be empty really */
1834 __skb_queue_purge(&tp->ucopy.prequeue);
1835
1836 /* Clean up a referenced TCP bind bucket. */
1837 if (inet_csk(sk)->icsk_bind_hash)
1838 inet_put_port(sk);
1839
1840 /*
1841 * If sendmsg cached page exists, toss it.
1842 */
1843 if (sk->sk_sndmsg_page) {
1844 __free_page(sk->sk_sndmsg_page);
1845 sk->sk_sndmsg_page = NULL;
1846 }
1847
1848 percpu_counter_dec(&tcp_sockets_allocated);
1849 }
1850
1851 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1852
1853 #ifdef CONFIG_PROC_FS
1854 /* Proc filesystem TCP sock list dumping. */
1855
1856 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1857 {
1858 return hlist_nulls_empty(head) ? NULL :
1859 list_entry(head->first, struct inet_timewait_sock, tw_node);
1860 }
1861
1862 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1863 {
1864 return !is_a_nulls(tw->tw_node.next) ?
1865 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1866 }
1867
1868 static void *listening_get_next(struct seq_file *seq, void *cur)
1869 {
1870 struct inet_connection_sock *icsk;
1871 struct hlist_nulls_node *node;
1872 struct sock *sk = cur;
1873 struct inet_listen_hashbucket *ilb;
1874 struct tcp_iter_state *st = seq->private;
1875 struct net *net = seq_file_net(seq);
1876
1877 if (!sk) {
1878 st->bucket = 0;
1879 ilb = &tcp_hashinfo.listening_hash[0];
1880 spin_lock_bh(&ilb->lock);
1881 sk = sk_nulls_head(&ilb->head);
1882 goto get_sk;
1883 }
1884 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1885 ++st->num;
1886
1887 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1888 struct request_sock *req = cur;
1889
1890 icsk = inet_csk(st->syn_wait_sk);
1891 req = req->dl_next;
1892 while (1) {
1893 while (req) {
1894 if (req->rsk_ops->family == st->family) {
1895 cur = req;
1896 goto out;
1897 }
1898 req = req->dl_next;
1899 }
1900 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1901 break;
1902 get_req:
1903 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1904 }
1905 sk = sk_next(st->syn_wait_sk);
1906 st->state = TCP_SEQ_STATE_LISTENING;
1907 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1908 } else {
1909 icsk = inet_csk(sk);
1910 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1911 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1912 goto start_req;
1913 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1914 sk = sk_next(sk);
1915 }
1916 get_sk:
1917 sk_nulls_for_each_from(sk, node) {
1918 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
1919 cur = sk;
1920 goto out;
1921 }
1922 icsk = inet_csk(sk);
1923 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1924 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1925 start_req:
1926 st->uid = sock_i_uid(sk);
1927 st->syn_wait_sk = sk;
1928 st->state = TCP_SEQ_STATE_OPENREQ;
1929 st->sbucket = 0;
1930 goto get_req;
1931 }
1932 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1933 }
1934 spin_unlock_bh(&ilb->lock);
1935 if (++st->bucket < INET_LHTABLE_SIZE) {
1936 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1937 spin_lock_bh(&ilb->lock);
1938 sk = sk_nulls_head(&ilb->head);
1939 goto get_sk;
1940 }
1941 cur = NULL;
1942 out:
1943 return cur;
1944 }
1945
1946 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1947 {
1948 void *rc = listening_get_next(seq, NULL);
1949
1950 while (rc && *pos) {
1951 rc = listening_get_next(seq, rc);
1952 --*pos;
1953 }
1954 return rc;
1955 }
1956
1957 static inline int empty_bucket(struct tcp_iter_state *st)
1958 {
1959 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
1960 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
1961 }
1962
1963 static void *established_get_first(struct seq_file *seq)
1964 {
1965 struct tcp_iter_state *st = seq->private;
1966 struct net *net = seq_file_net(seq);
1967 void *rc = NULL;
1968
1969 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
1970 struct sock *sk;
1971 struct hlist_nulls_node *node;
1972 struct inet_timewait_sock *tw;
1973 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1974
1975 /* Lockless fast path for the common case of empty buckets */
1976 if (empty_bucket(st))
1977 continue;
1978
1979 spin_lock_bh(lock);
1980 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1981 if (sk->sk_family != st->family ||
1982 !net_eq(sock_net(sk), net)) {
1983 continue;
1984 }
1985 rc = sk;
1986 goto out;
1987 }
1988 st->state = TCP_SEQ_STATE_TIME_WAIT;
1989 inet_twsk_for_each(tw, node,
1990 &tcp_hashinfo.ehash[st->bucket].twchain) {
1991 if (tw->tw_family != st->family ||
1992 !net_eq(twsk_net(tw), net)) {
1993 continue;
1994 }
1995 rc = tw;
1996 goto out;
1997 }
1998 spin_unlock_bh(lock);
1999 st->state = TCP_SEQ_STATE_ESTABLISHED;
2000 }
2001 out:
2002 return rc;
2003 }
2004
2005 static void *established_get_next(struct seq_file *seq, void *cur)
2006 {
2007 struct sock *sk = cur;
2008 struct inet_timewait_sock *tw;
2009 struct hlist_nulls_node *node;
2010 struct tcp_iter_state *st = seq->private;
2011 struct net *net = seq_file_net(seq);
2012
2013 ++st->num;
2014
2015 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2016 tw = cur;
2017 tw = tw_next(tw);
2018 get_tw:
2019 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2020 tw = tw_next(tw);
2021 }
2022 if (tw) {
2023 cur = tw;
2024 goto out;
2025 }
2026 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2027 st->state = TCP_SEQ_STATE_ESTABLISHED;
2028
2029 /* Look for next non empty bucket */
2030 while (++st->bucket < tcp_hashinfo.ehash_size &&
2031 empty_bucket(st))
2032 ;
2033 if (st->bucket >= tcp_hashinfo.ehash_size)
2034 return NULL;
2035
2036 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2037 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2038 } else
2039 sk = sk_nulls_next(sk);
2040
2041 sk_nulls_for_each_from(sk, node) {
2042 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2043 goto found;
2044 }
2045
2046 st->state = TCP_SEQ_STATE_TIME_WAIT;
2047 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2048 goto get_tw;
2049 found:
2050 cur = sk;
2051 out:
2052 return cur;
2053 }
2054
2055 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2056 {
2057 void *rc = established_get_first(seq);
2058
2059 while (rc && pos) {
2060 rc = established_get_next(seq, rc);
2061 --pos;
2062 }
2063 return rc;
2064 }
2065
2066 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2067 {
2068 void *rc;
2069 struct tcp_iter_state *st = seq->private;
2070
2071 st->state = TCP_SEQ_STATE_LISTENING;
2072 rc = listening_get_idx(seq, &pos);
2073
2074 if (!rc) {
2075 st->state = TCP_SEQ_STATE_ESTABLISHED;
2076 rc = established_get_idx(seq, pos);
2077 }
2078
2079 return rc;
2080 }
2081
2082 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2083 {
2084 struct tcp_iter_state *st = seq->private;
2085 st->state = TCP_SEQ_STATE_LISTENING;
2086 st->num = 0;
2087 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2088 }
2089
2090 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2091 {
2092 void *rc = NULL;
2093 struct tcp_iter_state *st;
2094
2095 if (v == SEQ_START_TOKEN) {
2096 rc = tcp_get_idx(seq, 0);
2097 goto out;
2098 }
2099 st = seq->private;
2100
2101 switch (st->state) {
2102 case TCP_SEQ_STATE_OPENREQ:
2103 case TCP_SEQ_STATE_LISTENING:
2104 rc = listening_get_next(seq, v);
2105 if (!rc) {
2106 st->state = TCP_SEQ_STATE_ESTABLISHED;
2107 rc = established_get_first(seq);
2108 }
2109 break;
2110 case TCP_SEQ_STATE_ESTABLISHED:
2111 case TCP_SEQ_STATE_TIME_WAIT:
2112 rc = established_get_next(seq, v);
2113 break;
2114 }
2115 out:
2116 ++*pos;
2117 return rc;
2118 }
2119
2120 static void tcp_seq_stop(struct seq_file *seq, void *v)
2121 {
2122 struct tcp_iter_state *st = seq->private;
2123
2124 switch (st->state) {
2125 case TCP_SEQ_STATE_OPENREQ:
2126 if (v) {
2127 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2128 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2129 }
2130 case TCP_SEQ_STATE_LISTENING:
2131 if (v != SEQ_START_TOKEN)
2132 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2133 break;
2134 case TCP_SEQ_STATE_TIME_WAIT:
2135 case TCP_SEQ_STATE_ESTABLISHED:
2136 if (v)
2137 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2138 break;
2139 }
2140 }
2141
2142 static int tcp_seq_open(struct inode *inode, struct file *file)
2143 {
2144 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2145 struct tcp_iter_state *s;
2146 int err;
2147
2148 err = seq_open_net(inode, file, &afinfo->seq_ops,
2149 sizeof(struct tcp_iter_state));
2150 if (err < 0)
2151 return err;
2152
2153 s = ((struct seq_file *)file->private_data)->private;
2154 s->family = afinfo->family;
2155 return 0;
2156 }
2157
2158 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2159 {
2160 int rc = 0;
2161 struct proc_dir_entry *p;
2162
2163 afinfo->seq_fops.open = tcp_seq_open;
2164 afinfo->seq_fops.read = seq_read;
2165 afinfo->seq_fops.llseek = seq_lseek;
2166 afinfo->seq_fops.release = seq_release_net;
2167
2168 afinfo->seq_ops.start = tcp_seq_start;
2169 afinfo->seq_ops.next = tcp_seq_next;
2170 afinfo->seq_ops.stop = tcp_seq_stop;
2171
2172 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2173 &afinfo->seq_fops, afinfo);
2174 if (!p)
2175 rc = -ENOMEM;
2176 return rc;
2177 }
2178
2179 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2180 {
2181 proc_net_remove(net, afinfo->name);
2182 }
2183
2184 static void get_openreq4(struct sock *sk, struct request_sock *req,
2185 struct seq_file *f, int i, int uid, int *len)
2186 {
2187 const struct inet_request_sock *ireq = inet_rsk(req);
2188 int ttd = req->expires - jiffies;
2189
2190 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2191 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2192 i,
2193 ireq->loc_addr,
2194 ntohs(inet_sk(sk)->sport),
2195 ireq->rmt_addr,
2196 ntohs(ireq->rmt_port),
2197 TCP_SYN_RECV,
2198 0, 0, /* could print option size, but that is af dependent. */
2199 1, /* timers active (only the expire timer) */
2200 jiffies_to_clock_t(ttd),
2201 req->retrans,
2202 uid,
2203 0, /* non standard timer */
2204 0, /* open_requests have no inode */
2205 atomic_read(&sk->sk_refcnt),
2206 req,
2207 len);
2208 }
2209
2210 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2211 {
2212 int timer_active;
2213 unsigned long timer_expires;
2214 struct tcp_sock *tp = tcp_sk(sk);
2215 const struct inet_connection_sock *icsk = inet_csk(sk);
2216 struct inet_sock *inet = inet_sk(sk);
2217 __be32 dest = inet->daddr;
2218 __be32 src = inet->rcv_saddr;
2219 __u16 destp = ntohs(inet->dport);
2220 __u16 srcp = ntohs(inet->sport);
2221
2222 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2223 timer_active = 1;
2224 timer_expires = icsk->icsk_timeout;
2225 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2226 timer_active = 4;
2227 timer_expires = icsk->icsk_timeout;
2228 } else if (timer_pending(&sk->sk_timer)) {
2229 timer_active = 2;
2230 timer_expires = sk->sk_timer.expires;
2231 } else {
2232 timer_active = 0;
2233 timer_expires = jiffies;
2234 }
2235
2236 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2237 "%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
2238 i, src, srcp, dest, destp, sk->sk_state,
2239 tp->write_seq - tp->snd_una,
2240 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2241 (tp->rcv_nxt - tp->copied_seq),
2242 timer_active,
2243 jiffies_to_clock_t(timer_expires - jiffies),
2244 icsk->icsk_retransmits,
2245 sock_i_uid(sk),
2246 icsk->icsk_probes_out,
2247 sock_i_ino(sk),
2248 atomic_read(&sk->sk_refcnt), sk,
2249 jiffies_to_clock_t(icsk->icsk_rto),
2250 jiffies_to_clock_t(icsk->icsk_ack.ato),
2251 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2252 tp->snd_cwnd,
2253 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2254 len);
2255 }
2256
2257 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2258 struct seq_file *f, int i, int *len)
2259 {
2260 __be32 dest, src;
2261 __u16 destp, srcp;
2262 int ttd = tw->tw_ttd - jiffies;
2263
2264 if (ttd < 0)
2265 ttd = 0;
2266
2267 dest = tw->tw_daddr;
2268 src = tw->tw_rcv_saddr;
2269 destp = ntohs(tw->tw_dport);
2270 srcp = ntohs(tw->tw_sport);
2271
2272 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2273 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2274 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2275 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2276 atomic_read(&tw->tw_refcnt), tw, len);
2277 }
2278
2279 #define TMPSZ 150
2280
2281 static int tcp4_seq_show(struct seq_file *seq, void *v)
2282 {
2283 struct tcp_iter_state *st;
2284 int len;
2285
2286 if (v == SEQ_START_TOKEN) {
2287 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2288 " sl local_address rem_address st tx_queue "
2289 "rx_queue tr tm->when retrnsmt uid timeout "
2290 "inode");
2291 goto out;
2292 }
2293 st = seq->private;
2294
2295 switch (st->state) {
2296 case TCP_SEQ_STATE_LISTENING:
2297 case TCP_SEQ_STATE_ESTABLISHED:
2298 get_tcp4_sock(v, seq, st->num, &len);
2299 break;
2300 case TCP_SEQ_STATE_OPENREQ:
2301 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2302 break;
2303 case TCP_SEQ_STATE_TIME_WAIT:
2304 get_timewait4_sock(v, seq, st->num, &len);
2305 break;
2306 }
2307 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2308 out:
2309 return 0;
2310 }
2311
2312 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2313 .name = "tcp",
2314 .family = AF_INET,
2315 .seq_fops = {
2316 .owner = THIS_MODULE,
2317 },
2318 .seq_ops = {
2319 .show = tcp4_seq_show,
2320 },
2321 };
2322
2323 static int tcp4_proc_init_net(struct net *net)
2324 {
2325 return tcp_proc_register(net, &tcp4_seq_afinfo);
2326 }
2327
2328 static void tcp4_proc_exit_net(struct net *net)
2329 {
2330 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2331 }
2332
2333 static struct pernet_operations tcp4_net_ops = {
2334 .init = tcp4_proc_init_net,
2335 .exit = tcp4_proc_exit_net,
2336 };
2337
2338 int __init tcp4_proc_init(void)
2339 {
2340 return register_pernet_subsys(&tcp4_net_ops);
2341 }
2342
2343 void tcp4_proc_exit(void)
2344 {
2345 unregister_pernet_subsys(&tcp4_net_ops);
2346 }
2347 #endif /* CONFIG_PROC_FS */
2348
2349 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2350 {
2351 struct iphdr *iph = ip_hdr(skb);
2352
2353 switch (skb->ip_summed) {
2354 case CHECKSUM_COMPLETE:
2355 if (!tcp_v4_check(skb->len, iph->saddr, iph->daddr,
2356 skb->csum)) {
2357 skb->ip_summed = CHECKSUM_UNNECESSARY;
2358 break;
2359 }
2360
2361 /* fall through */
2362 case CHECKSUM_NONE:
2363 NAPI_GRO_CB(skb)->flush = 1;
2364 return NULL;
2365 }
2366
2367 return tcp_gro_receive(head, skb);
2368 }
2369 EXPORT_SYMBOL(tcp4_gro_receive);
2370
2371 int tcp4_gro_complete(struct sk_buff *skb)
2372 {
2373 struct iphdr *iph = ip_hdr(skb);
2374 struct tcphdr *th = tcp_hdr(skb);
2375
2376 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2377 iph->saddr, iph->daddr, 0);
2378 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2379
2380 return tcp_gro_complete(skb);
2381 }
2382 EXPORT_SYMBOL(tcp4_gro_complete);
2383
2384 struct proto tcp_prot = {
2385 .name = "TCP",
2386 .owner = THIS_MODULE,
2387 .close = tcp_close,
2388 .connect = tcp_v4_connect,
2389 .disconnect = tcp_disconnect,
2390 .accept = inet_csk_accept,
2391 .ioctl = tcp_ioctl,
2392 .init = tcp_v4_init_sock,
2393 .destroy = tcp_v4_destroy_sock,
2394 .shutdown = tcp_shutdown,
2395 .setsockopt = tcp_setsockopt,
2396 .getsockopt = tcp_getsockopt,
2397 .recvmsg = tcp_recvmsg,
2398 .backlog_rcv = tcp_v4_do_rcv,
2399 .hash = inet_hash,
2400 .unhash = inet_unhash,
2401 .get_port = inet_csk_get_port,
2402 .enter_memory_pressure = tcp_enter_memory_pressure,
2403 .sockets_allocated = &tcp_sockets_allocated,
2404 .orphan_count = &tcp_orphan_count,
2405 .memory_allocated = &tcp_memory_allocated,
2406 .memory_pressure = &tcp_memory_pressure,
2407 .sysctl_mem = sysctl_tcp_mem,
2408 .sysctl_wmem = sysctl_tcp_wmem,
2409 .sysctl_rmem = sysctl_tcp_rmem,
2410 .max_header = MAX_TCP_HEADER,
2411 .obj_size = sizeof(struct tcp_sock),
2412 .slab_flags = SLAB_DESTROY_BY_RCU,
2413 .twsk_prot = &tcp_timewait_sock_ops,
2414 .rsk_prot = &tcp_request_sock_ops,
2415 .h.hashinfo = &tcp_hashinfo,
2416 #ifdef CONFIG_COMPAT
2417 .compat_setsockopt = compat_tcp_setsockopt,
2418 .compat_getsockopt = compat_tcp_getsockopt,
2419 #endif
2420 };
2421
2422
2423 static int __net_init tcp_sk_init(struct net *net)
2424 {
2425 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2426 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2427 }
2428
2429 static void __net_exit tcp_sk_exit(struct net *net)
2430 {
2431 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2432 inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
2433 }
2434
2435 static struct pernet_operations __net_initdata tcp_sk_ops = {
2436 .init = tcp_sk_init,
2437 .exit = tcp_sk_exit,
2438 };
2439
2440 void __init tcp_v4_init(void)
2441 {
2442 inet_hashinfo_init(&tcp_hashinfo);
2443 if (register_pernet_device(&tcp_sk_ops))
2444 panic("Failed to create the TCP control socket.\n");
2445 }
2446
2447 EXPORT_SYMBOL(ipv4_specific);
2448 EXPORT_SYMBOL(tcp_hashinfo);
2449 EXPORT_SYMBOL(tcp_prot);
2450 EXPORT_SYMBOL(tcp_v4_conn_request);
2451 EXPORT_SYMBOL(tcp_v4_connect);
2452 EXPORT_SYMBOL(tcp_v4_do_rcv);
2453 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2454 EXPORT_SYMBOL(tcp_v4_send_check);
2455 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2456
2457 #ifdef CONFIG_PROC_FS
2458 EXPORT_SYMBOL(tcp_proc_register);
2459 EXPORT_SYMBOL(tcp_proc_unregister);
2460 #endif
2461 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2462
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