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ucc_geth: Fix build breakage caused by a merge
[linux-2.6/mini2440.git] / net / ipv4 / tcp_ipv4.c
blobd0a314879d811981dec4d00afde21aa3582a7116
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/bottom_half.h>
55 #include <linux/types.h>
56 #include <linux/fcntl.h>
57 #include <linux/module.h>
58 #include <linux/random.h>
59 #include <linux/cache.h>
60 #include <linux/jhash.h>
61 #include <linux/init.h>
62 #include <linux/times.h>
63
64 #include <net/net_namespace.h>
65 #include <net/icmp.h>
66 #include <net/inet_hashtables.h>
67 #include <net/tcp.h>
68 #include <net/transp_v6.h>
69 #include <net/ipv6.h>
70 #include <net/inet_common.h>
71 #include <net/timewait_sock.h>
72 #include <net/xfrm.h>
73 #include <net/netdma.h>
74
75 #include <linux/inet.h>
76 #include <linux/ipv6.h>
77 #include <linux/stddef.h>
78 #include <linux/proc_fs.h>
79 #include <linux/seq_file.h>
80
81 #include <linux/crypto.h>
82 #include <linux/scatterlist.h>
83
84 int sysctl_tcp_tw_reuse __read_mostly;
85 int sysctl_tcp_low_latency __read_mostly;
86
87
88 #ifdef CONFIG_TCP_MD5SIG
89 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
90 __be32 addr);
91 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
92 __be32 daddr, __be32 saddr, struct tcphdr *th);
93 #else
94 static inline
95 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
96 {
97 return NULL;
98 }
99 #endif
100
101 struct inet_hashinfo tcp_hashinfo;
102
103 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
104 {
105 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
106 ip_hdr(skb)->saddr,
107 tcp_hdr(skb)->dest,
108 tcp_hdr(skb)->source);
109 }
110
111 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112 {
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 /* With PAWS, it is safe from the viewpoint
117 of data integrity. Even without PAWS it is safe provided sequence
118 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119
120 Actually, the idea is close to VJ's one, only timestamp cache is
121 held not per host, but per port pair and TW bucket is used as state
122 holder.
123
124 If TW bucket has been already destroyed we fall back to VJ's scheme
125 and use initial timestamp retrieved from peer table.
126 */
127 if (tcptw->tw_ts_recent_stamp &&
128 (twp == NULL || (sysctl_tcp_tw_reuse &&
129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
131 if (tp->write_seq == 0)
132 tp->write_seq = 1;
133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
135 sock_hold(sktw);
136 return 1;
137 }
138
139 return 0;
140 }
141
142 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
143
144 /* This will initiate an outgoing connection. */
145 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
146 {
147 struct inet_sock *inet = inet_sk(sk);
148 struct tcp_sock *tp = tcp_sk(sk);
149 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
150 struct rtable *rt;
151 __be32 daddr, nexthop;
152 int tmp;
153 int err;
154
155 if (addr_len < sizeof(struct sockaddr_in))
156 return -EINVAL;
157
158 if (usin->sin_family != AF_INET)
159 return -EAFNOSUPPORT;
160
161 nexthop = daddr = usin->sin_addr.s_addr;
162 if (inet->opt && inet->opt->srr) {
163 if (!daddr)
164 return -EINVAL;
165 nexthop = inet->opt->faddr;
166 }
167
168 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
169 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
170 IPPROTO_TCP,
171 inet->sport, usin->sin_port, sk, 1);
172 if (tmp < 0) {
173 if (tmp == -ENETUNREACH)
174 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
175 return tmp;
176 }
177
178 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
179 ip_rt_put(rt);
180 return -ENETUNREACH;
181 }
182
183 if (!inet->opt || !inet->opt->srr)
184 daddr = rt->rt_dst;
185
186 if (!inet->saddr)
187 inet->saddr = rt->rt_src;
188 inet->rcv_saddr = inet->saddr;
189
190 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
191 /* Reset inherited state */
192 tp->rx_opt.ts_recent = 0;
193 tp->rx_opt.ts_recent_stamp = 0;
194 tp->write_seq = 0;
195 }
196
197 if (tcp_death_row.sysctl_tw_recycle &&
198 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
199 struct inet_peer *peer = rt_get_peer(rt);
200 /*
201 * VJ's idea. We save last timestamp seen from
202 * the destination in peer table, when entering state
203 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
204 * when trying new connection.
205 */
206 if (peer != NULL &&
207 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
208 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
209 tp->rx_opt.ts_recent = peer->tcp_ts;
210 }
211 }
212
213 inet->dport = usin->sin_port;
214 inet->daddr = daddr;
215
216 inet_csk(sk)->icsk_ext_hdr_len = 0;
217 if (inet->opt)
218 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
219
220 tp->rx_opt.mss_clamp = 536;
221
222 /* Socket identity is still unknown (sport may be zero).
223 * However we set state to SYN-SENT and not releasing socket
224 * lock select source port, enter ourselves into the hash tables and
225 * complete initialization after this.
226 */
227 tcp_set_state(sk, TCP_SYN_SENT);
228 err = inet_hash_connect(&tcp_death_row, sk);
229 if (err)
230 goto failure;
231
232 err = ip_route_newports(&rt, IPPROTO_TCP,
233 inet->sport, inet->dport, sk);
234 if (err)
235 goto failure;
236
237 /* OK, now commit destination to socket. */
238 sk->sk_gso_type = SKB_GSO_TCPV4;
239 sk_setup_caps(sk, &rt->u.dst);
240
241 if (!tp->write_seq)
242 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
243 inet->daddr,
244 inet->sport,
245 usin->sin_port);
246
247 inet->id = tp->write_seq ^ jiffies;
248
249 err = tcp_connect(sk);
250 rt = NULL;
251 if (err)
252 goto failure;
253
254 return 0;
255
256 failure:
257 /*
258 * This unhashes the socket and releases the local port,
259 * if necessary.
260 */
261 tcp_set_state(sk, TCP_CLOSE);
262 ip_rt_put(rt);
263 sk->sk_route_caps = 0;
264 inet->dport = 0;
265 return err;
266 }
267
268 /*
269 * This routine does path mtu discovery as defined in RFC1191.
270 */
271 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
272 {
273 struct dst_entry *dst;
274 struct inet_sock *inet = inet_sk(sk);
275
276 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
277 * send out by Linux are always <576bytes so they should go through
278 * unfragmented).
279 */
280 if (sk->sk_state == TCP_LISTEN)
281 return;
282
283 /* We don't check in the destentry if pmtu discovery is forbidden
284 * on this route. We just assume that no packet_to_big packets
285 * are send back when pmtu discovery is not active.
286 * There is a small race when the user changes this flag in the
287 * route, but I think that's acceptable.
288 */
289 if ((dst = __sk_dst_check(sk, 0)) == NULL)
290 return;
291
292 dst->ops->update_pmtu(dst, mtu);
293
294 /* Something is about to be wrong... Remember soft error
295 * for the case, if this connection will not able to recover.
296 */
297 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
298 sk->sk_err_soft = EMSGSIZE;
299
300 mtu = dst_mtu(dst);
301
302 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
303 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
304 tcp_sync_mss(sk, mtu);
305
306 /* Resend the TCP packet because it's
307 * clear that the old packet has been
308 * dropped. This is the new "fast" path mtu
309 * discovery.
310 */
311 tcp_simple_retransmit(sk);
312 } /* else let the usual retransmit timer handle it */
313 }
314
315 /*
316 * This routine is called by the ICMP module when it gets some
317 * sort of error condition. If err < 0 then the socket should
318 * be closed and the error returned to the user. If err > 0
319 * it's just the icmp type << 8 | icmp code. After adjustment
320 * header points to the first 8 bytes of the tcp header. We need
321 * to find the appropriate port.
322 *
323 * The locking strategy used here is very "optimistic". When
324 * someone else accesses the socket the ICMP is just dropped
325 * and for some paths there is no check at all.
326 * A more general error queue to queue errors for later handling
327 * is probably better.
328 *
329 */
330
331 void tcp_v4_err(struct sk_buff *skb, u32 info)
332 {
333 struct iphdr *iph = (struct iphdr *)skb->data;
334 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
335 struct tcp_sock *tp;
336 struct inet_sock *inet;
337 const int type = icmp_hdr(skb)->type;
338 const int code = icmp_hdr(skb)->code;
339 struct sock *sk;
340 __u32 seq;
341 int err;
342 struct net *net = dev_net(skb->dev);
343
344 if (skb->len < (iph->ihl << 2) + 8) {
345 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
346 return;
347 }
348
349 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
350 iph->saddr, th->source, inet_iif(skb));
351 if (!sk) {
352 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
353 return;
354 }
355 if (sk->sk_state == TCP_TIME_WAIT) {
356 inet_twsk_put(inet_twsk(sk));
357 return;
358 }
359
360 bh_lock_sock(sk);
361 /* If too many ICMPs get dropped on busy
362 * servers this needs to be solved differently.
363 */
364 if (sock_owned_by_user(sk))
365 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
366
367 if (sk->sk_state == TCP_CLOSE)
368 goto out;
369
370 tp = tcp_sk(sk);
371 seq = ntohl(th->seq);
372 if (sk->sk_state != TCP_LISTEN &&
373 !between(seq, tp->snd_una, tp->snd_nxt)) {
374 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
375 goto out;
376 }
377
378 switch (type) {
379 case ICMP_SOURCE_QUENCH:
380 /* Just silently ignore these. */
381 goto out;
382 case ICMP_PARAMETERPROB:
383 err = EPROTO;
384 break;
385 case ICMP_DEST_UNREACH:
386 if (code > NR_ICMP_UNREACH)
387 goto out;
388
389 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
390 if (!sock_owned_by_user(sk))
391 do_pmtu_discovery(sk, iph, info);
392 goto out;
393 }
394
395 err = icmp_err_convert[code].errno;
396 break;
397 case ICMP_TIME_EXCEEDED:
398 err = EHOSTUNREACH;
399 break;
400 default:
401 goto out;
402 }
403
404 switch (sk->sk_state) {
405 struct request_sock *req, **prev;
406 case TCP_LISTEN:
407 if (sock_owned_by_user(sk))
408 goto out;
409
410 req = inet_csk_search_req(sk, &prev, th->dest,
411 iph->daddr, iph->saddr);
412 if (!req)
413 goto out;
414
415 /* ICMPs are not backlogged, hence we cannot get
416 an established socket here.
417 */
418 WARN_ON(req->sk);
419
420 if (seq != tcp_rsk(req)->snt_isn) {
421 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
422 goto out;
423 }
424
425 /*
426 * Still in SYN_RECV, just remove it silently.
427 * There is no good way to pass the error to the newly
428 * created socket, and POSIX does not want network
429 * errors returned from accept().
430 */
431 inet_csk_reqsk_queue_drop(sk, req, prev);
432 goto out;
433
434 case TCP_SYN_SENT:
435 case TCP_SYN_RECV: /* Cannot happen.
436 It can f.e. if SYNs crossed.
437 */
438 if (!sock_owned_by_user(sk)) {
439 sk->sk_err = err;
440
441 sk->sk_error_report(sk);
442
443 tcp_done(sk);
444 } else {
445 sk->sk_err_soft = err;
446 }
447 goto out;
448 }
449
450 /* If we've already connected we will keep trying
451 * until we time out, or the user gives up.
452 *
453 * rfc1122 4.2.3.9 allows to consider as hard errors
454 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
455 * but it is obsoleted by pmtu discovery).
456 *
457 * Note, that in modern internet, where routing is unreliable
458 * and in each dark corner broken firewalls sit, sending random
459 * errors ordered by their masters even this two messages finally lose
460 * their original sense (even Linux sends invalid PORT_UNREACHs)
461 *
462 * Now we are in compliance with RFCs.
463 * --ANK (980905)
464 */
465
466 inet = inet_sk(sk);
467 if (!sock_owned_by_user(sk) && inet->recverr) {
468 sk->sk_err = err;
469 sk->sk_error_report(sk);
470 } else { /* Only an error on timeout */
471 sk->sk_err_soft = err;
472 }
473
474 out:
475 bh_unlock_sock(sk);
476 sock_put(sk);
477 }
478
479 /* This routine computes an IPv4 TCP checksum. */
480 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
481 {
482 struct inet_sock *inet = inet_sk(sk);
483 struct tcphdr *th = tcp_hdr(skb);
484
485 if (skb->ip_summed == CHECKSUM_PARTIAL) {
486 th->check = ~tcp_v4_check(len, inet->saddr,
487 inet->daddr, 0);
488 skb->csum_start = skb_transport_header(skb) - skb->head;
489 skb->csum_offset = offsetof(struct tcphdr, check);
490 } else {
491 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
492 csum_partial(th,
493 th->doff << 2,
494 skb->csum));
495 }
496 }
497
498 int tcp_v4_gso_send_check(struct sk_buff *skb)
499 {
500 const struct iphdr *iph;
501 struct tcphdr *th;
502
503 if (!pskb_may_pull(skb, sizeof(*th)))
504 return -EINVAL;
505
506 iph = ip_hdr(skb);
507 th = tcp_hdr(skb);
508
509 th->check = 0;
510 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 skb->ip_summed = CHECKSUM_PARTIAL;
514 return 0;
515 }
516
517 /*
518 * This routine will send an RST to the other tcp.
519 *
520 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
521 * for reset.
522 * Answer: if a packet caused RST, it is not for a socket
523 * existing in our system, if it is matched to a socket,
524 * it is just duplicate segment or bug in other side's TCP.
525 * So that we build reply only basing on parameters
526 * arrived with segment.
527 * Exception: precedence violation. We do not implement it in any case.
528 */
529
530 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
531 {
532 struct tcphdr *th = tcp_hdr(skb);
533 struct {
534 struct tcphdr th;
535 #ifdef CONFIG_TCP_MD5SIG
536 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
537 #endif
538 } rep;
539 struct ip_reply_arg arg;
540 #ifdef CONFIG_TCP_MD5SIG
541 struct tcp_md5sig_key *key;
542 #endif
543 struct net *net;
544
545 /* Never send a reset in response to a reset. */
546 if (th->rst)
547 return;
548
549 if (skb->rtable->rt_type != RTN_LOCAL)
550 return;
551
552 /* Swap the send and the receive. */
553 memset(&rep, 0, sizeof(rep));
554 rep.th.dest = th->source;
555 rep.th.source = th->dest;
556 rep.th.doff = sizeof(struct tcphdr) / 4;
557 rep.th.rst = 1;
558
559 if (th->ack) {
560 rep.th.seq = th->ack_seq;
561 } else {
562 rep.th.ack = 1;
563 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
564 skb->len - (th->doff << 2));
565 }
566
567 memset(&arg, 0, sizeof(arg));
568 arg.iov[0].iov_base = (unsigned char *)&rep;
569 arg.iov[0].iov_len = sizeof(rep.th);
570
571 #ifdef CONFIG_TCP_MD5SIG
572 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
573 if (key) {
574 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
575 (TCPOPT_NOP << 16) |
576 (TCPOPT_MD5SIG << 8) |
577 TCPOLEN_MD5SIG);
578 /* Update length and the length the header thinks exists */
579 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
580 rep.th.doff = arg.iov[0].iov_len / 4;
581
582 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
583 key, ip_hdr(skb)->saddr,
584 ip_hdr(skb)->daddr, &rep.th);
585 }
586 #endif
587 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
588 ip_hdr(skb)->saddr, /* XXX */
589 arg.iov[0].iov_len, IPPROTO_TCP, 0);
590 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
591 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
592
593 net = dev_net(skb->dst->dev);
594 ip_send_reply(net->ipv4.tcp_sock, skb,
595 &arg, arg.iov[0].iov_len);
596
597 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
598 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
599 }
600
601 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
602 outside socket context is ugly, certainly. What can I do?
603 */
604
605 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
606 u32 win, u32 ts, int oif,
607 struct tcp_md5sig_key *key,
608 int reply_flags)
609 {
610 struct tcphdr *th = tcp_hdr(skb);
611 struct {
612 struct tcphdr th;
613 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
614 #ifdef CONFIG_TCP_MD5SIG
615 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
616 #endif
617 ];
618 } rep;
619 struct ip_reply_arg arg;
620 struct net *net = dev_net(skb->dst->dev);
621
622 memset(&rep.th, 0, sizeof(struct tcphdr));
623 memset(&arg, 0, sizeof(arg));
624
625 arg.iov[0].iov_base = (unsigned char *)&rep;
626 arg.iov[0].iov_len = sizeof(rep.th);
627 if (ts) {
628 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
629 (TCPOPT_TIMESTAMP << 8) |
630 TCPOLEN_TIMESTAMP);
631 rep.opt[1] = htonl(tcp_time_stamp);
632 rep.opt[2] = htonl(ts);
633 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
634 }
635
636 /* Swap the send and the receive. */
637 rep.th.dest = th->source;
638 rep.th.source = th->dest;
639 rep.th.doff = arg.iov[0].iov_len / 4;
640 rep.th.seq = htonl(seq);
641 rep.th.ack_seq = htonl(ack);
642 rep.th.ack = 1;
643 rep.th.window = htons(win);
644
645 #ifdef CONFIG_TCP_MD5SIG
646 if (key) {
647 int offset = (ts) ? 3 : 0;
648
649 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
650 (TCPOPT_NOP << 16) |
651 (TCPOPT_MD5SIG << 8) |
652 TCPOLEN_MD5SIG);
653 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
654 rep.th.doff = arg.iov[0].iov_len/4;
655
656 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
657 key, ip_hdr(skb)->saddr,
658 ip_hdr(skb)->daddr, &rep.th);
659 }
660 #endif
661 arg.flags = reply_flags;
662 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
663 ip_hdr(skb)->saddr, /* XXX */
664 arg.iov[0].iov_len, IPPROTO_TCP, 0);
665 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
666 if (oif)
667 arg.bound_dev_if = oif;
668
669 ip_send_reply(net->ipv4.tcp_sock, skb,
670 &arg, arg.iov[0].iov_len);
671
672 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
673 }
674
675 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
676 {
677 struct inet_timewait_sock *tw = inet_twsk(sk);
678 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
679
680 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
681 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
682 tcptw->tw_ts_recent,
683 tw->tw_bound_dev_if,
684 tcp_twsk_md5_key(tcptw),
685 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
686 );
687
688 inet_twsk_put(tw);
689 }
690
691 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
692 struct request_sock *req)
693 {
694 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
695 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
696 req->ts_recent,
697 0,
698 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
699 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
700 }
701
702 /*
703 * Send a SYN-ACK after having received a SYN.
704 * This still operates on a request_sock only, not on a big
705 * socket.
706 */
707 static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
708 struct dst_entry *dst)
709 {
710 const struct inet_request_sock *ireq = inet_rsk(req);
711 int err = -1;
712 struct sk_buff * skb;
713
714 /* First, grab a route. */
715 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
716 return -1;
717
718 skb = tcp_make_synack(sk, dst, req);
719
720 if (skb) {
721 struct tcphdr *th = tcp_hdr(skb);
722
723 th->check = tcp_v4_check(skb->len,
724 ireq->loc_addr,
725 ireq->rmt_addr,
726 csum_partial(th, skb->len,
727 skb->csum));
728
729 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
730 ireq->rmt_addr,
731 ireq->opt);
732 err = net_xmit_eval(err);
733 }
734
735 dst_release(dst);
736 return err;
737 }
738
739 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
740 {
741 return __tcp_v4_send_synack(sk, req, NULL);
742 }
743
744 /*
745 * IPv4 request_sock destructor.
746 */
747 static void tcp_v4_reqsk_destructor(struct request_sock *req)
748 {
749 kfree(inet_rsk(req)->opt);
750 }
751
752 #ifdef CONFIG_SYN_COOKIES
753 static void syn_flood_warning(struct sk_buff *skb)
754 {
755 static unsigned long warntime;
756
757 if (time_after(jiffies, (warntime + HZ * 60))) {
758 warntime = jiffies;
759 printk(KERN_INFO
760 "possible SYN flooding on port %d. Sending cookies.\n",
761 ntohs(tcp_hdr(skb)->dest));
762 }
763 }
764 #endif
765
766 /*
767 * Save and compile IPv4 options into the request_sock if needed.
768 */
769 static struct ip_options *tcp_v4_save_options(struct sock *sk,
770 struct sk_buff *skb)
771 {
772 struct ip_options *opt = &(IPCB(skb)->opt);
773 struct ip_options *dopt = NULL;
774
775 if (opt && opt->optlen) {
776 int opt_size = optlength(opt);
777 dopt = kmalloc(opt_size, GFP_ATOMIC);
778 if (dopt) {
779 if (ip_options_echo(dopt, skb)) {
780 kfree(dopt);
781 dopt = NULL;
782 }
783 }
784 }
785 return dopt;
786 }
787
788 #ifdef CONFIG_TCP_MD5SIG
789 /*
790 * RFC2385 MD5 checksumming requires a mapping of
791 * IP address->MD5 Key.
792 * We need to maintain these in the sk structure.
793 */
794
795 /* Find the Key structure for an address. */
796 static struct tcp_md5sig_key *
797 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
798 {
799 struct tcp_sock *tp = tcp_sk(sk);
800 int i;
801
802 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
803 return NULL;
804 for (i = 0; i < tp->md5sig_info->entries4; i++) {
805 if (tp->md5sig_info->keys4[i].addr == addr)
806 return &tp->md5sig_info->keys4[i].base;
807 }
808 return NULL;
809 }
810
811 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
812 struct sock *addr_sk)
813 {
814 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
815 }
816
817 EXPORT_SYMBOL(tcp_v4_md5_lookup);
818
819 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
820 struct request_sock *req)
821 {
822 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
823 }
824
825 /* This can be called on a newly created socket, from other files */
826 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
827 u8 *newkey, u8 newkeylen)
828 {
829 /* Add Key to the list */
830 struct tcp_md5sig_key *key;
831 struct tcp_sock *tp = tcp_sk(sk);
832 struct tcp4_md5sig_key *keys;
833
834 key = tcp_v4_md5_do_lookup(sk, addr);
835 if (key) {
836 /* Pre-existing entry - just update that one. */
837 kfree(key->key);
838 key->key = newkey;
839 key->keylen = newkeylen;
840 } else {
841 struct tcp_md5sig_info *md5sig;
842
843 if (!tp->md5sig_info) {
844 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
845 GFP_ATOMIC);
846 if (!tp->md5sig_info) {
847 kfree(newkey);
848 return -ENOMEM;
849 }
850 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
851 }
852 if (tcp_alloc_md5sig_pool() == NULL) {
853 kfree(newkey);
854 return -ENOMEM;
855 }
856 md5sig = tp->md5sig_info;
857
858 if (md5sig->alloced4 == md5sig->entries4) {
859 keys = kmalloc((sizeof(*keys) *
860 (md5sig->entries4 + 1)), GFP_ATOMIC);
861 if (!keys) {
862 kfree(newkey);
863 tcp_free_md5sig_pool();
864 return -ENOMEM;
865 }
866
867 if (md5sig->entries4)
868 memcpy(keys, md5sig->keys4,
869 sizeof(*keys) * md5sig->entries4);
870
871 /* Free old key list, and reference new one */
872 kfree(md5sig->keys4);
873 md5sig->keys4 = keys;
874 md5sig->alloced4++;
875 }
876 md5sig->entries4++;
877 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
878 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
879 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
880 }
881 return 0;
882 }
883
884 EXPORT_SYMBOL(tcp_v4_md5_do_add);
885
886 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
887 u8 *newkey, u8 newkeylen)
888 {
889 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
890 newkey, newkeylen);
891 }
892
893 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
894 {
895 struct tcp_sock *tp = tcp_sk(sk);
896 int i;
897
898 for (i = 0; i < tp->md5sig_info->entries4; i++) {
899 if (tp->md5sig_info->keys4[i].addr == addr) {
900 /* Free the key */
901 kfree(tp->md5sig_info->keys4[i].base.key);
902 tp->md5sig_info->entries4--;
903
904 if (tp->md5sig_info->entries4 == 0) {
905 kfree(tp->md5sig_info->keys4);
906 tp->md5sig_info->keys4 = NULL;
907 tp->md5sig_info->alloced4 = 0;
908 } else if (tp->md5sig_info->entries4 != i) {
909 /* Need to do some manipulation */
910 memmove(&tp->md5sig_info->keys4[i],
911 &tp->md5sig_info->keys4[i+1],
912 (tp->md5sig_info->entries4 - i) *
913 sizeof(struct tcp4_md5sig_key));
914 }
915 tcp_free_md5sig_pool();
916 return 0;
917 }
918 }
919 return -ENOENT;
920 }
921
922 EXPORT_SYMBOL(tcp_v4_md5_do_del);
923
924 static void tcp_v4_clear_md5_list(struct sock *sk)
925 {
926 struct tcp_sock *tp = tcp_sk(sk);
927
928 /* Free each key, then the set of key keys,
929 * the crypto element, and then decrement our
930 * hold on the last resort crypto.
931 */
932 if (tp->md5sig_info->entries4) {
933 int i;
934 for (i = 0; i < tp->md5sig_info->entries4; i++)
935 kfree(tp->md5sig_info->keys4[i].base.key);
936 tp->md5sig_info->entries4 = 0;
937 tcp_free_md5sig_pool();
938 }
939 if (tp->md5sig_info->keys4) {
940 kfree(tp->md5sig_info->keys4);
941 tp->md5sig_info->keys4 = NULL;
942 tp->md5sig_info->alloced4 = 0;
943 }
944 }
945
946 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
947 int optlen)
948 {
949 struct tcp_md5sig cmd;
950 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
951 u8 *newkey;
952
953 if (optlen < sizeof(cmd))
954 return -EINVAL;
955
956 if (copy_from_user(&cmd, optval, sizeof(cmd)))
957 return -EFAULT;
958
959 if (sin->sin_family != AF_INET)
960 return -EINVAL;
961
962 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
963 if (!tcp_sk(sk)->md5sig_info)
964 return -ENOENT;
965 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
966 }
967
968 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
969 return -EINVAL;
970
971 if (!tcp_sk(sk)->md5sig_info) {
972 struct tcp_sock *tp = tcp_sk(sk);
973 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
974
975 if (!p)
976 return -EINVAL;
977
978 tp->md5sig_info = p;
979 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
980 }
981
982 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
983 if (!newkey)
984 return -ENOMEM;
985 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
986 newkey, cmd.tcpm_keylen);
987 }
988
989 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
990 __be32 daddr, __be32 saddr, int nbytes)
991 {
992 struct tcp4_pseudohdr *bp;
993 struct scatterlist sg;
994
995 bp = &hp->md5_blk.ip4;
996
997 /*
998 * 1. the TCP pseudo-header (in the order: source IP address,
999 * destination IP address, zero-padded protocol number, and
1000 * segment length)
1001 */
1002 bp->saddr = saddr;
1003 bp->daddr = daddr;
1004 bp->pad = 0;
1005 bp->protocol = IPPROTO_TCP;
1006 bp->len = cpu_to_be16(nbytes);
1007
1008 sg_init_one(&sg, bp, sizeof(*bp));
1009 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1010 }
1011
1012 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1013 __be32 daddr, __be32 saddr, struct tcphdr *th)
1014 {
1015 struct tcp_md5sig_pool *hp;
1016 struct hash_desc *desc;
1017
1018 hp = tcp_get_md5sig_pool();
1019 if (!hp)
1020 goto clear_hash_noput;
1021 desc = &hp->md5_desc;
1022
1023 if (crypto_hash_init(desc))
1024 goto clear_hash;
1025 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1026 goto clear_hash;
1027 if (tcp_md5_hash_header(hp, th))
1028 goto clear_hash;
1029 if (tcp_md5_hash_key(hp, key))
1030 goto clear_hash;
1031 if (crypto_hash_final(desc, md5_hash))
1032 goto clear_hash;
1033
1034 tcp_put_md5sig_pool();
1035 return 0;
1036
1037 clear_hash:
1038 tcp_put_md5sig_pool();
1039 clear_hash_noput:
1040 memset(md5_hash, 0, 16);
1041 return 1;
1042 }
1043
1044 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1045 struct sock *sk, struct request_sock *req,
1046 struct sk_buff *skb)
1047 {
1048 struct tcp_md5sig_pool *hp;
1049 struct hash_desc *desc;
1050 struct tcphdr *th = tcp_hdr(skb);
1051 __be32 saddr, daddr;
1052
1053 if (sk) {
1054 saddr = inet_sk(sk)->saddr;
1055 daddr = inet_sk(sk)->daddr;
1056 } else if (req) {
1057 saddr = inet_rsk(req)->loc_addr;
1058 daddr = inet_rsk(req)->rmt_addr;
1059 } else {
1060 const struct iphdr *iph = ip_hdr(skb);
1061 saddr = iph->saddr;
1062 daddr = iph->daddr;
1063 }
1064
1065 hp = tcp_get_md5sig_pool();
1066 if (!hp)
1067 goto clear_hash_noput;
1068 desc = &hp->md5_desc;
1069
1070 if (crypto_hash_init(desc))
1071 goto clear_hash;
1072
1073 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1074 goto clear_hash;
1075 if (tcp_md5_hash_header(hp, th))
1076 goto clear_hash;
1077 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1078 goto clear_hash;
1079 if (tcp_md5_hash_key(hp, key))
1080 goto clear_hash;
1081 if (crypto_hash_final(desc, md5_hash))
1082 goto clear_hash;
1083
1084 tcp_put_md5sig_pool();
1085 return 0;
1086
1087 clear_hash:
1088 tcp_put_md5sig_pool();
1089 clear_hash_noput:
1090 memset(md5_hash, 0, 16);
1091 return 1;
1092 }
1093
1094 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1095
1096 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1097 {
1098 /*
1099 * This gets called for each TCP segment that arrives
1100 * so we want to be efficient.
1101 * We have 3 drop cases:
1102 * o No MD5 hash and one expected.
1103 * o MD5 hash and we're not expecting one.
1104 * o MD5 hash and its wrong.
1105 */
1106 __u8 *hash_location = NULL;
1107 struct tcp_md5sig_key *hash_expected;
1108 const struct iphdr *iph = ip_hdr(skb);
1109 struct tcphdr *th = tcp_hdr(skb);
1110 int genhash;
1111 unsigned char newhash[16];
1112
1113 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1114 hash_location = tcp_parse_md5sig_option(th);
1115
1116 /* We've parsed the options - do we have a hash? */
1117 if (!hash_expected && !hash_location)
1118 return 0;
1119
1120 if (hash_expected && !hash_location) {
1121 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1122 return 1;
1123 }
1124
1125 if (!hash_expected && hash_location) {
1126 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1127 return 1;
1128 }
1129
1130 /* Okay, so this is hash_expected and hash_location -
1131 * so we need to calculate the checksum.
1132 */
1133 genhash = tcp_v4_md5_hash_skb(newhash,
1134 hash_expected,
1135 NULL, NULL, skb);
1136
1137 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1138 if (net_ratelimit()) {
1139 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1140 &iph->saddr, ntohs(th->source),
1141 &iph->daddr, ntohs(th->dest),
1142 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1143 }
1144 return 1;
1145 }
1146 return 0;
1147 }
1148
1149 #endif
1150
1151 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1152 .family = PF_INET,
1153 .obj_size = sizeof(struct tcp_request_sock),
1154 .rtx_syn_ack = tcp_v4_send_synack,
1155 .send_ack = tcp_v4_reqsk_send_ack,
1156 .destructor = tcp_v4_reqsk_destructor,
1157 .send_reset = tcp_v4_send_reset,
1158 };
1159
1160 #ifdef CONFIG_TCP_MD5SIG
1161 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1162 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1163 };
1164 #endif
1165
1166 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1167 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1168 .twsk_unique = tcp_twsk_unique,
1169 .twsk_destructor= tcp_twsk_destructor,
1170 };
1171
1172 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1173 {
1174 struct inet_request_sock *ireq;
1175 struct tcp_options_received tmp_opt;
1176 struct request_sock *req;
1177 __be32 saddr = ip_hdr(skb)->saddr;
1178 __be32 daddr = ip_hdr(skb)->daddr;
1179 __u32 isn = TCP_SKB_CB(skb)->when;
1180 struct dst_entry *dst = NULL;
1181 #ifdef CONFIG_SYN_COOKIES
1182 int want_cookie = 0;
1183 #else
1184 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1185 #endif
1186
1187 /* Never answer to SYNs send to broadcast or multicast */
1188 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1189 goto drop;
1190
1191 /* TW buckets are converted to open requests without
1192 * limitations, they conserve resources and peer is
1193 * evidently real one.
1194 */
1195 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1196 #ifdef CONFIG_SYN_COOKIES
1197 if (sysctl_tcp_syncookies) {
1198 want_cookie = 1;
1199 } else
1200 #endif
1201 goto drop;
1202 }
1203
1204 /* Accept backlog is full. If we have already queued enough
1205 * of warm entries in syn queue, drop request. It is better than
1206 * clogging syn queue with openreqs with exponentially increasing
1207 * timeout.
1208 */
1209 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1210 goto drop;
1211
1212 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1213 if (!req)
1214 goto drop;
1215
1216 #ifdef CONFIG_TCP_MD5SIG
1217 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1218 #endif
1219
1220 tcp_clear_options(&tmp_opt);
1221 tmp_opt.mss_clamp = 536;
1222 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1223
1224 tcp_parse_options(skb, &tmp_opt, 0);
1225
1226 if (want_cookie && !tmp_opt.saw_tstamp)
1227 tcp_clear_options(&tmp_opt);
1228
1229 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1230
1231 tcp_openreq_init(req, &tmp_opt, skb);
1232
1233 if (security_inet_conn_request(sk, skb, req))
1234 goto drop_and_free;
1235
1236 ireq = inet_rsk(req);
1237 ireq->loc_addr = daddr;
1238 ireq->rmt_addr = saddr;
1239 ireq->no_srccheck = inet_sk(sk)->transparent;
1240 ireq->opt = tcp_v4_save_options(sk, skb);
1241 if (!want_cookie)
1242 TCP_ECN_create_request(req, tcp_hdr(skb));
1243
1244 if (want_cookie) {
1245 #ifdef CONFIG_SYN_COOKIES
1246 syn_flood_warning(skb);
1247 req->cookie_ts = tmp_opt.tstamp_ok;
1248 #endif
1249 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1250 } else if (!isn) {
1251 struct inet_peer *peer = NULL;
1252
1253 /* VJ's idea. We save last timestamp seen
1254 * from the destination in peer table, when entering
1255 * state TIME-WAIT, and check against it before
1256 * accepting new connection request.
1257 *
1258 * If "isn" is not zero, this request hit alive
1259 * timewait bucket, so that all the necessary checks
1260 * are made in the function processing timewait state.
1261 */
1262 if (tmp_opt.saw_tstamp &&
1263 tcp_death_row.sysctl_tw_recycle &&
1264 (dst = inet_csk_route_req(sk, req)) != NULL &&
1265 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1266 peer->v4daddr == saddr) {
1267 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1268 (s32)(peer->tcp_ts - req->ts_recent) >
1269 TCP_PAWS_WINDOW) {
1270 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1271 goto drop_and_release;
1272 }
1273 }
1274 /* Kill the following clause, if you dislike this way. */
1275 else if (!sysctl_tcp_syncookies &&
1276 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1277 (sysctl_max_syn_backlog >> 2)) &&
1278 (!peer || !peer->tcp_ts_stamp) &&
1279 (!dst || !dst_metric(dst, RTAX_RTT))) {
1280 /* Without syncookies last quarter of
1281 * backlog is filled with destinations,
1282 * proven to be alive.
1283 * It means that we continue to communicate
1284 * to destinations, already remembered
1285 * to the moment of synflood.
1286 */
1287 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1288 &saddr, ntohs(tcp_hdr(skb)->source));
1289 goto drop_and_release;
1290 }
1291
1292 isn = tcp_v4_init_sequence(skb);
1293 }
1294 tcp_rsk(req)->snt_isn = isn;
1295
1296 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1297 goto drop_and_free;
1298
1299 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1300 return 0;
1301
1302 drop_and_release:
1303 dst_release(dst);
1304 drop_and_free:
1305 reqsk_free(req);
1306 drop:
1307 return 0;
1308 }
1309
1310
1311 /*
1312 * The three way handshake has completed - we got a valid synack -
1313 * now create the new socket.
1314 */
1315 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1316 struct request_sock *req,
1317 struct dst_entry *dst)
1318 {
1319 struct inet_request_sock *ireq;
1320 struct inet_sock *newinet;
1321 struct tcp_sock *newtp;
1322 struct sock *newsk;
1323 #ifdef CONFIG_TCP_MD5SIG
1324 struct tcp_md5sig_key *key;
1325 #endif
1326
1327 if (sk_acceptq_is_full(sk))
1328 goto exit_overflow;
1329
1330 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1331 goto exit;
1332
1333 newsk = tcp_create_openreq_child(sk, req, skb);
1334 if (!newsk)
1335 goto exit;
1336
1337 newsk->sk_gso_type = SKB_GSO_TCPV4;
1338 sk_setup_caps(newsk, dst);
1339
1340 newtp = tcp_sk(newsk);
1341 newinet = inet_sk(newsk);
1342 ireq = inet_rsk(req);
1343 newinet->daddr = ireq->rmt_addr;
1344 newinet->rcv_saddr = ireq->loc_addr;
1345 newinet->saddr = ireq->loc_addr;
1346 newinet->opt = ireq->opt;
1347 ireq->opt = NULL;
1348 newinet->mc_index = inet_iif(skb);
1349 newinet->mc_ttl = ip_hdr(skb)->ttl;
1350 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1351 if (newinet->opt)
1352 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1353 newinet->id = newtp->write_seq ^ jiffies;
1354
1355 tcp_mtup_init(newsk);
1356 tcp_sync_mss(newsk, dst_mtu(dst));
1357 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1358 if (tcp_sk(sk)->rx_opt.user_mss &&
1359 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1360 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1361
1362 tcp_initialize_rcv_mss(newsk);
1363
1364 #ifdef CONFIG_TCP_MD5SIG
1365 /* Copy over the MD5 key from the original socket */
1366 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1367 /*
1368 * We're using one, so create a matching key
1369 * on the newsk structure. If we fail to get
1370 * memory, then we end up not copying the key
1371 * across. Shucks.
1372 */
1373 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1374 if (newkey != NULL)
1375 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1376 newkey, key->keylen);
1377 newsk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1378 }
1379 #endif
1380
1381 __inet_hash_nolisten(newsk);
1382 __inet_inherit_port(sk, newsk);
1383
1384 return newsk;
1385
1386 exit_overflow:
1387 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1388 exit:
1389 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1390 dst_release(dst);
1391 return NULL;
1392 }
1393
1394 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1395 {
1396 struct tcphdr *th = tcp_hdr(skb);
1397 const struct iphdr *iph = ip_hdr(skb);
1398 struct sock *nsk;
1399 struct request_sock **prev;
1400 /* Find possible connection requests. */
1401 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1402 iph->saddr, iph->daddr);
1403 if (req)
1404 return tcp_check_req(sk, skb, req, prev);
1405
1406 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1407 th->source, iph->daddr, th->dest, inet_iif(skb));
1408
1409 if (nsk) {
1410 if (nsk->sk_state != TCP_TIME_WAIT) {
1411 bh_lock_sock(nsk);
1412 return nsk;
1413 }
1414 inet_twsk_put(inet_twsk(nsk));
1415 return NULL;
1416 }
1417
1418 #ifdef CONFIG_SYN_COOKIES
1419 if (!th->rst && !th->syn && th->ack)
1420 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1421 #endif
1422 return sk;
1423 }
1424
1425 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1426 {
1427 const struct iphdr *iph = ip_hdr(skb);
1428
1429 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1430 if (!tcp_v4_check(skb->len, iph->saddr,
1431 iph->daddr, skb->csum)) {
1432 skb->ip_summed = CHECKSUM_UNNECESSARY;
1433 return 0;
1434 }
1435 }
1436
1437 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1438 skb->len, IPPROTO_TCP, 0);
1439
1440 if (skb->len <= 76) {
1441 return __skb_checksum_complete(skb);
1442 }
1443 return 0;
1444 }
1445
1446
1447 /* The socket must have it's spinlock held when we get
1448 * here.
1449 *
1450 * We have a potential double-lock case here, so even when
1451 * doing backlog processing we use the BH locking scheme.
1452 * This is because we cannot sleep with the original spinlock
1453 * held.
1454 */
1455 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1456 {
1457 struct sock *rsk;
1458 #ifdef CONFIG_TCP_MD5SIG
1459 /*
1460 * We really want to reject the packet as early as possible
1461 * if:
1462 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1463 * o There is an MD5 option and we're not expecting one
1464 */
1465 if (tcp_v4_inbound_md5_hash(sk, skb))
1466 goto discard;
1467 #endif
1468
1469 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1470 TCP_CHECK_TIMER(sk);
1471 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1472 rsk = sk;
1473 goto reset;
1474 }
1475 TCP_CHECK_TIMER(sk);
1476 return 0;
1477 }
1478
1479 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1480 goto csum_err;
1481
1482 if (sk->sk_state == TCP_LISTEN) {
1483 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1484 if (!nsk)
1485 goto discard;
1486
1487 if (nsk != sk) {
1488 if (tcp_child_process(sk, nsk, skb)) {
1489 rsk = nsk;
1490 goto reset;
1491 }
1492 return 0;
1493 }
1494 }
1495
1496 TCP_CHECK_TIMER(sk);
1497 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1498 rsk = sk;
1499 goto reset;
1500 }
1501 TCP_CHECK_TIMER(sk);
1502 return 0;
1503
1504 reset:
1505 tcp_v4_send_reset(rsk, skb);
1506 discard:
1507 kfree_skb(skb);
1508 /* Be careful here. If this function gets more complicated and
1509 * gcc suffers from register pressure on the x86, sk (in %ebx)
1510 * might be destroyed here. This current version compiles correctly,
1511 * but you have been warned.
1512 */
1513 return 0;
1514
1515 csum_err:
1516 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1517 goto discard;
1518 }
1519
1520 /*
1521 * From tcp_input.c
1522 */
1523
1524 int tcp_v4_rcv(struct sk_buff *skb)
1525 {
1526 const struct iphdr *iph;
1527 struct tcphdr *th;
1528 struct sock *sk;
1529 int ret;
1530 struct net *net = dev_net(skb->dev);
1531
1532 if (skb->pkt_type != PACKET_HOST)
1533 goto discard_it;
1534
1535 /* Count it even if it's bad */
1536 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1537
1538 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1539 goto discard_it;
1540
1541 th = tcp_hdr(skb);
1542
1543 if (th->doff < sizeof(struct tcphdr) / 4)
1544 goto bad_packet;
1545 if (!pskb_may_pull(skb, th->doff * 4))
1546 goto discard_it;
1547
1548 /* An explanation is required here, I think.
1549 * Packet length and doff are validated by header prediction,
1550 * provided case of th->doff==0 is eliminated.
1551 * So, we defer the checks. */
1552 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1553 goto bad_packet;
1554
1555 th = tcp_hdr(skb);
1556 iph = ip_hdr(skb);
1557 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1558 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1559 skb->len - th->doff * 4);
1560 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1561 TCP_SKB_CB(skb)->when = 0;
1562 TCP_SKB_CB(skb)->flags = iph->tos;
1563 TCP_SKB_CB(skb)->sacked = 0;
1564
1565 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1566 if (!sk)
1567 goto no_tcp_socket;
1568
1569 process:
1570 if (sk->sk_state == TCP_TIME_WAIT)
1571 goto do_time_wait;
1572
1573 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1574 goto discard_and_relse;
1575 nf_reset(skb);
1576
1577 if (sk_filter(sk, skb))
1578 goto discard_and_relse;
1579
1580 skb->dev = NULL;
1581
1582 bh_lock_sock_nested(sk);
1583 ret = 0;
1584 if (!sock_owned_by_user(sk)) {
1585 #ifdef CONFIG_NET_DMA
1586 struct tcp_sock *tp = tcp_sk(sk);
1587 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1588 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1589 if (tp->ucopy.dma_chan)
1590 ret = tcp_v4_do_rcv(sk, skb);
1591 else
1592 #endif
1593 {
1594 if (!tcp_prequeue(sk, skb))
1595 ret = tcp_v4_do_rcv(sk, skb);
1596 }
1597 } else
1598 sk_add_backlog(sk, skb);
1599 bh_unlock_sock(sk);
1600
1601 sock_put(sk);
1602
1603 return ret;
1604
1605 no_tcp_socket:
1606 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1607 goto discard_it;
1608
1609 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1610 bad_packet:
1611 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1612 } else {
1613 tcp_v4_send_reset(NULL, skb);
1614 }
1615
1616 discard_it:
1617 /* Discard frame. */
1618 kfree_skb(skb);
1619 return 0;
1620
1621 discard_and_relse:
1622 sock_put(sk);
1623 goto discard_it;
1624
1625 do_time_wait:
1626 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1627 inet_twsk_put(inet_twsk(sk));
1628 goto discard_it;
1629 }
1630
1631 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1632 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1633 inet_twsk_put(inet_twsk(sk));
1634 goto discard_it;
1635 }
1636 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1637 case TCP_TW_SYN: {
1638 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1639 &tcp_hashinfo,
1640 iph->daddr, th->dest,
1641 inet_iif(skb));
1642 if (sk2) {
1643 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1644 inet_twsk_put(inet_twsk(sk));
1645 sk = sk2;
1646 goto process;
1647 }
1648 /* Fall through to ACK */
1649 }
1650 case TCP_TW_ACK:
1651 tcp_v4_timewait_ack(sk, skb);
1652 break;
1653 case TCP_TW_RST:
1654 goto no_tcp_socket;
1655 case TCP_TW_SUCCESS:;
1656 }
1657 goto discard_it;
1658 }
1659
1660 /* VJ's idea. Save last timestamp seen from this destination
1661 * and hold it at least for normal timewait interval to use for duplicate
1662 * segment detection in subsequent connections, before they enter synchronized
1663 * state.
1664 */
1665
1666 int tcp_v4_remember_stamp(struct sock *sk)
1667 {
1668 struct inet_sock *inet = inet_sk(sk);
1669 struct tcp_sock *tp = tcp_sk(sk);
1670 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1671 struct inet_peer *peer = NULL;
1672 int release_it = 0;
1673
1674 if (!rt || rt->rt_dst != inet->daddr) {
1675 peer = inet_getpeer(inet->daddr, 1);
1676 release_it = 1;
1677 } else {
1678 if (!rt->peer)
1679 rt_bind_peer(rt, 1);
1680 peer = rt->peer;
1681 }
1682
1683 if (peer) {
1684 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1685 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1686 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1687 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1688 peer->tcp_ts = tp->rx_opt.ts_recent;
1689 }
1690 if (release_it)
1691 inet_putpeer(peer);
1692 return 1;
1693 }
1694
1695 return 0;
1696 }
1697
1698 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1699 {
1700 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1701
1702 if (peer) {
1703 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1704
1705 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1706 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1707 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1708 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1709 peer->tcp_ts = tcptw->tw_ts_recent;
1710 }
1711 inet_putpeer(peer);
1712 return 1;
1713 }
1714
1715 return 0;
1716 }
1717
1718 struct inet_connection_sock_af_ops ipv4_specific = {
1719 .queue_xmit = ip_queue_xmit,
1720 .send_check = tcp_v4_send_check,
1721 .rebuild_header = inet_sk_rebuild_header,
1722 .conn_request = tcp_v4_conn_request,
1723 .syn_recv_sock = tcp_v4_syn_recv_sock,
1724 .remember_stamp = tcp_v4_remember_stamp,
1725 .net_header_len = sizeof(struct iphdr),
1726 .setsockopt = ip_setsockopt,
1727 .getsockopt = ip_getsockopt,
1728 .addr2sockaddr = inet_csk_addr2sockaddr,
1729 .sockaddr_len = sizeof(struct sockaddr_in),
1730 .bind_conflict = inet_csk_bind_conflict,
1731 #ifdef CONFIG_COMPAT
1732 .compat_setsockopt = compat_ip_setsockopt,
1733 .compat_getsockopt = compat_ip_getsockopt,
1734 #endif
1735 };
1736
1737 #ifdef CONFIG_TCP_MD5SIG
1738 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1739 .md5_lookup = tcp_v4_md5_lookup,
1740 .calc_md5_hash = tcp_v4_md5_hash_skb,
1741 .md5_add = tcp_v4_md5_add_func,
1742 .md5_parse = tcp_v4_parse_md5_keys,
1743 };
1744 #endif
1745
1746 /* NOTE: A lot of things set to zero explicitly by call to
1747 * sk_alloc() so need not be done here.
1748 */
1749 static int tcp_v4_init_sock(struct sock *sk)
1750 {
1751 struct inet_connection_sock *icsk = inet_csk(sk);
1752 struct tcp_sock *tp = tcp_sk(sk);
1753
1754 skb_queue_head_init(&tp->out_of_order_queue);
1755 tcp_init_xmit_timers(sk);
1756 tcp_prequeue_init(tp);
1757
1758 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1759 tp->mdev = TCP_TIMEOUT_INIT;
1760
1761 /* So many TCP implementations out there (incorrectly) count the
1762 * initial SYN frame in their delayed-ACK and congestion control
1763 * algorithms that we must have the following bandaid to talk
1764 * efficiently to them. -DaveM
1765 */
1766 tp->snd_cwnd = 2;
1767
1768 /* See draft-stevens-tcpca-spec-01 for discussion of the
1769 * initialization of these values.
1770 */
1771 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1772 tp->snd_cwnd_clamp = ~0;
1773 tp->mss_cache = 536;
1774
1775 tp->reordering = sysctl_tcp_reordering;
1776 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1777
1778 sk->sk_state = TCP_CLOSE;
1779
1780 sk->sk_write_space = sk_stream_write_space;
1781 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1782
1783 icsk->icsk_af_ops = &ipv4_specific;
1784 icsk->icsk_sync_mss = tcp_sync_mss;
1785 #ifdef CONFIG_TCP_MD5SIG
1786 tp->af_specific = &tcp_sock_ipv4_specific;
1787 #endif
1788
1789 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1790 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1791
1792 local_bh_disable();
1793 percpu_counter_inc(&tcp_sockets_allocated);
1794 local_bh_enable();
1795
1796 return 0;
1797 }
1798
1799 void tcp_v4_destroy_sock(struct sock *sk)
1800 {
1801 struct tcp_sock *tp = tcp_sk(sk);
1802
1803 tcp_clear_xmit_timers(sk);
1804
1805 tcp_cleanup_congestion_control(sk);
1806
1807 /* Cleanup up the write buffer. */
1808 tcp_write_queue_purge(sk);
1809
1810 /* Cleans up our, hopefully empty, out_of_order_queue. */
1811 __skb_queue_purge(&tp->out_of_order_queue);
1812
1813 #ifdef CONFIG_TCP_MD5SIG
1814 /* Clean up the MD5 key list, if any */
1815 if (tp->md5sig_info) {
1816 tcp_v4_clear_md5_list(sk);
1817 kfree(tp->md5sig_info);
1818 tp->md5sig_info = NULL;
1819 }
1820 #endif
1821
1822 #ifdef CONFIG_NET_DMA
1823 /* Cleans up our sk_async_wait_queue */
1824 __skb_queue_purge(&sk->sk_async_wait_queue);
1825 #endif
1826
1827 /* Clean prequeue, it must be empty really */
1828 __skb_queue_purge(&tp->ucopy.prequeue);
1829
1830 /* Clean up a referenced TCP bind bucket. */
1831 if (inet_csk(sk)->icsk_bind_hash)
1832 inet_put_port(sk);
1833
1834 /*
1835 * If sendmsg cached page exists, toss it.
1836 */
1837 if (sk->sk_sndmsg_page) {
1838 __free_page(sk->sk_sndmsg_page);
1839 sk->sk_sndmsg_page = NULL;
1840 }
1841
1842 percpu_counter_dec(&tcp_sockets_allocated);
1843 }
1844
1845 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1846
1847 #ifdef CONFIG_PROC_FS
1848 /* Proc filesystem TCP sock list dumping. */
1849
1850 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1851 {
1852 return hlist_nulls_empty(head) ? NULL :
1853 list_entry(head->first, struct inet_timewait_sock, tw_node);
1854 }
1855
1856 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1857 {
1858 return !is_a_nulls(tw->tw_node.next) ?
1859 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1860 }
1861
1862 static void *listening_get_next(struct seq_file *seq, void *cur)
1863 {
1864 struct inet_connection_sock *icsk;
1865 struct hlist_nulls_node *node;
1866 struct sock *sk = cur;
1867 struct inet_listen_hashbucket *ilb;
1868 struct tcp_iter_state *st = seq->private;
1869 struct net *net = seq_file_net(seq);
1870
1871 if (!sk) {
1872 st->bucket = 0;
1873 ilb = &tcp_hashinfo.listening_hash[0];
1874 spin_lock_bh(&ilb->lock);
1875 sk = sk_nulls_head(&ilb->head);
1876 goto get_sk;
1877 }
1878 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1879 ++st->num;
1880
1881 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1882 struct request_sock *req = cur;
1883
1884 icsk = inet_csk(st->syn_wait_sk);
1885 req = req->dl_next;
1886 while (1) {
1887 while (req) {
1888 if (req->rsk_ops->family == st->family) {
1889 cur = req;
1890 goto out;
1891 }
1892 req = req->dl_next;
1893 }
1894 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1895 break;
1896 get_req:
1897 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1898 }
1899 sk = sk_next(st->syn_wait_sk);
1900 st->state = TCP_SEQ_STATE_LISTENING;
1901 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1902 } else {
1903 icsk = inet_csk(sk);
1904 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1905 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1906 goto start_req;
1907 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1908 sk = sk_next(sk);
1909 }
1910 get_sk:
1911 sk_nulls_for_each_from(sk, node) {
1912 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
1913 cur = sk;
1914 goto out;
1915 }
1916 icsk = inet_csk(sk);
1917 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1918 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1919 start_req:
1920 st->uid = sock_i_uid(sk);
1921 st->syn_wait_sk = sk;
1922 st->state = TCP_SEQ_STATE_OPENREQ;
1923 st->sbucket = 0;
1924 goto get_req;
1925 }
1926 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1927 }
1928 spin_unlock_bh(&ilb->lock);
1929 if (++st->bucket < INET_LHTABLE_SIZE) {
1930 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1931 spin_lock_bh(&ilb->lock);
1932 sk = sk_nulls_head(&ilb->head);
1933 goto get_sk;
1934 }
1935 cur = NULL;
1936 out:
1937 return cur;
1938 }
1939
1940 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1941 {
1942 void *rc = listening_get_next(seq, NULL);
1943
1944 while (rc && *pos) {
1945 rc = listening_get_next(seq, rc);
1946 --*pos;
1947 }
1948 return rc;
1949 }
1950
1951 static inline int empty_bucket(struct tcp_iter_state *st)
1952 {
1953 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
1954 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
1955 }
1956
1957 static void *established_get_first(struct seq_file *seq)
1958 {
1959 struct tcp_iter_state *st = seq->private;
1960 struct net *net = seq_file_net(seq);
1961 void *rc = NULL;
1962
1963 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
1964 struct sock *sk;
1965 struct hlist_nulls_node *node;
1966 struct inet_timewait_sock *tw;
1967 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1968
1969 /* Lockless fast path for the common case of empty buckets */
1970 if (empty_bucket(st))
1971 continue;
1972
1973 spin_lock_bh(lock);
1974 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1975 if (sk->sk_family != st->family ||
1976 !net_eq(sock_net(sk), net)) {
1977 continue;
1978 }
1979 rc = sk;
1980 goto out;
1981 }
1982 st->state = TCP_SEQ_STATE_TIME_WAIT;
1983 inet_twsk_for_each(tw, node,
1984 &tcp_hashinfo.ehash[st->bucket].twchain) {
1985 if (tw->tw_family != st->family ||
1986 !net_eq(twsk_net(tw), net)) {
1987 continue;
1988 }
1989 rc = tw;
1990 goto out;
1991 }
1992 spin_unlock_bh(lock);
1993 st->state = TCP_SEQ_STATE_ESTABLISHED;
1994 }
1995 out:
1996 return rc;
1997 }
1998
1999 static void *established_get_next(struct seq_file *seq, void *cur)
2000 {
2001 struct sock *sk = cur;
2002 struct inet_timewait_sock *tw;
2003 struct hlist_nulls_node *node;
2004 struct tcp_iter_state *st = seq->private;
2005 struct net *net = seq_file_net(seq);
2006
2007 ++st->num;
2008
2009 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2010 tw = cur;
2011 tw = tw_next(tw);
2012 get_tw:
2013 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2014 tw = tw_next(tw);
2015 }
2016 if (tw) {
2017 cur = tw;
2018 goto out;
2019 }
2020 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2021 st->state = TCP_SEQ_STATE_ESTABLISHED;
2022
2023 /* Look for next non empty bucket */
2024 while (++st->bucket < tcp_hashinfo.ehash_size &&
2025 empty_bucket(st))
2026 ;
2027 if (st->bucket >= tcp_hashinfo.ehash_size)
2028 return NULL;
2029
2030 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2031 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2032 } else
2033 sk = sk_nulls_next(sk);
2034
2035 sk_nulls_for_each_from(sk, node) {
2036 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2037 goto found;
2038 }
2039
2040 st->state = TCP_SEQ_STATE_TIME_WAIT;
2041 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2042 goto get_tw;
2043 found:
2044 cur = sk;
2045 out:
2046 return cur;
2047 }
2048
2049 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2050 {
2051 void *rc = established_get_first(seq);
2052
2053 while (rc && pos) {
2054 rc = established_get_next(seq, rc);
2055 --pos;
2056 }
2057 return rc;
2058 }
2059
2060 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2061 {
2062 void *rc;
2063 struct tcp_iter_state *st = seq->private;
2064
2065 st->state = TCP_SEQ_STATE_LISTENING;
2066 rc = listening_get_idx(seq, &pos);
2067
2068 if (!rc) {
2069 st->state = TCP_SEQ_STATE_ESTABLISHED;
2070 rc = established_get_idx(seq, pos);
2071 }
2072
2073 return rc;
2074 }
2075
2076 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2077 {
2078 struct tcp_iter_state *st = seq->private;
2079 st->state = TCP_SEQ_STATE_LISTENING;
2080 st->num = 0;
2081 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2082 }
2083
2084 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2085 {
2086 void *rc = NULL;
2087 struct tcp_iter_state *st;
2088
2089 if (v == SEQ_START_TOKEN) {
2090 rc = tcp_get_idx(seq, 0);
2091 goto out;
2092 }
2093 st = seq->private;
2094
2095 switch (st->state) {
2096 case TCP_SEQ_STATE_OPENREQ:
2097 case TCP_SEQ_STATE_LISTENING:
2098 rc = listening_get_next(seq, v);
2099 if (!rc) {
2100 st->state = TCP_SEQ_STATE_ESTABLISHED;
2101 rc = established_get_first(seq);
2102 }
2103 break;
2104 case TCP_SEQ_STATE_ESTABLISHED:
2105 case TCP_SEQ_STATE_TIME_WAIT:
2106 rc = established_get_next(seq, v);
2107 break;
2108 }
2109 out:
2110 ++*pos;
2111 return rc;
2112 }
2113
2114 static void tcp_seq_stop(struct seq_file *seq, void *v)
2115 {
2116 struct tcp_iter_state *st = seq->private;
2117
2118 switch (st->state) {
2119 case TCP_SEQ_STATE_OPENREQ:
2120 if (v) {
2121 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2122 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2123 }
2124 case TCP_SEQ_STATE_LISTENING:
2125 if (v != SEQ_START_TOKEN)
2126 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2127 break;
2128 case TCP_SEQ_STATE_TIME_WAIT:
2129 case TCP_SEQ_STATE_ESTABLISHED:
2130 if (v)
2131 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2132 break;
2133 }
2134 }
2135
2136 static int tcp_seq_open(struct inode *inode, struct file *file)
2137 {
2138 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2139 struct tcp_iter_state *s;
2140 int err;
2141
2142 err = seq_open_net(inode, file, &afinfo->seq_ops,
2143 sizeof(struct tcp_iter_state));
2144 if (err < 0)
2145 return err;
2146
2147 s = ((struct seq_file *)file->private_data)->private;
2148 s->family = afinfo->family;
2149 return 0;
2150 }
2151
2152 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2153 {
2154 int rc = 0;
2155 struct proc_dir_entry *p;
2156
2157 afinfo->seq_fops.open = tcp_seq_open;
2158 afinfo->seq_fops.read = seq_read;
2159 afinfo->seq_fops.llseek = seq_lseek;
2160 afinfo->seq_fops.release = seq_release_net;
2161
2162 afinfo->seq_ops.start = tcp_seq_start;
2163 afinfo->seq_ops.next = tcp_seq_next;
2164 afinfo->seq_ops.stop = tcp_seq_stop;
2165
2166 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2167 &afinfo->seq_fops, afinfo);
2168 if (!p)
2169 rc = -ENOMEM;
2170 return rc;
2171 }
2172
2173 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2174 {
2175 proc_net_remove(net, afinfo->name);
2176 }
2177
2178 static void get_openreq4(struct sock *sk, struct request_sock *req,
2179 struct seq_file *f, int i, int uid, int *len)
2180 {
2181 const struct inet_request_sock *ireq = inet_rsk(req);
2182 int ttd = req->expires - jiffies;
2183
2184 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2185 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2186 i,
2187 ireq->loc_addr,
2188 ntohs(inet_sk(sk)->sport),
2189 ireq->rmt_addr,
2190 ntohs(ireq->rmt_port),
2191 TCP_SYN_RECV,
2192 0, 0, /* could print option size, but that is af dependent. */
2193 1, /* timers active (only the expire timer) */
2194 jiffies_to_clock_t(ttd),
2195 req->retrans,
2196 uid,
2197 0, /* non standard timer */
2198 0, /* open_requests have no inode */
2199 atomic_read(&sk->sk_refcnt),
2200 req,
2201 len);
2202 }
2203
2204 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2205 {
2206 int timer_active;
2207 unsigned long timer_expires;
2208 struct tcp_sock *tp = tcp_sk(sk);
2209 const struct inet_connection_sock *icsk = inet_csk(sk);
2210 struct inet_sock *inet = inet_sk(sk);
2211 __be32 dest = inet->daddr;
2212 __be32 src = inet->rcv_saddr;
2213 __u16 destp = ntohs(inet->dport);
2214 __u16 srcp = ntohs(inet->sport);
2215
2216 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2217 timer_active = 1;
2218 timer_expires = icsk->icsk_timeout;
2219 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2220 timer_active = 4;
2221 timer_expires = icsk->icsk_timeout;
2222 } else if (timer_pending(&sk->sk_timer)) {
2223 timer_active = 2;
2224 timer_expires = sk->sk_timer.expires;
2225 } else {
2226 timer_active = 0;
2227 timer_expires = jiffies;
2228 }
2229
2230 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2231 "%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
2232 i, src, srcp, dest, destp, sk->sk_state,
2233 tp->write_seq - tp->snd_una,
2234 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2235 (tp->rcv_nxt - tp->copied_seq),
2236 timer_active,
2237 jiffies_to_clock_t(timer_expires - jiffies),
2238 icsk->icsk_retransmits,
2239 sock_i_uid(sk),
2240 icsk->icsk_probes_out,
2241 sock_i_ino(sk),
2242 atomic_read(&sk->sk_refcnt), sk,
2243 jiffies_to_clock_t(icsk->icsk_rto),
2244 jiffies_to_clock_t(icsk->icsk_ack.ato),
2245 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2246 tp->snd_cwnd,
2247 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2248 len);
2249 }
2250
2251 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2252 struct seq_file *f, int i, int *len)
2253 {
2254 __be32 dest, src;
2255 __u16 destp, srcp;
2256 int ttd = tw->tw_ttd - jiffies;
2257
2258 if (ttd < 0)
2259 ttd = 0;
2260
2261 dest = tw->tw_daddr;
2262 src = tw->tw_rcv_saddr;
2263 destp = ntohs(tw->tw_dport);
2264 srcp = ntohs(tw->tw_sport);
2265
2266 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2267 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2268 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2269 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2270 atomic_read(&tw->tw_refcnt), tw, len);
2271 }
2272
2273 #define TMPSZ 150
2274
2275 static int tcp4_seq_show(struct seq_file *seq, void *v)
2276 {
2277 struct tcp_iter_state *st;
2278 int len;
2279
2280 if (v == SEQ_START_TOKEN) {
2281 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2282 " sl local_address rem_address st tx_queue "
2283 "rx_queue tr tm->when retrnsmt uid timeout "
2284 "inode");
2285 goto out;
2286 }
2287 st = seq->private;
2288
2289 switch (st->state) {
2290 case TCP_SEQ_STATE_LISTENING:
2291 case TCP_SEQ_STATE_ESTABLISHED:
2292 get_tcp4_sock(v, seq, st->num, &len);
2293 break;
2294 case TCP_SEQ_STATE_OPENREQ:
2295 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2296 break;
2297 case TCP_SEQ_STATE_TIME_WAIT:
2298 get_timewait4_sock(v, seq, st->num, &len);
2299 break;
2300 }
2301 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2302 out:
2303 return 0;
2304 }
2305
2306 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2307 .name = "tcp",
2308 .family = AF_INET,
2309 .seq_fops = {
2310 .owner = THIS_MODULE,
2311 },
2312 .seq_ops = {
2313 .show = tcp4_seq_show,
2314 },
2315 };
2316
2317 static int tcp4_proc_init_net(struct net *net)
2318 {
2319 return tcp_proc_register(net, &tcp4_seq_afinfo);
2320 }
2321
2322 static void tcp4_proc_exit_net(struct net *net)
2323 {
2324 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2325 }
2326
2327 static struct pernet_operations tcp4_net_ops = {
2328 .init = tcp4_proc_init_net,
2329 .exit = tcp4_proc_exit_net,
2330 };
2331
2332 int __init tcp4_proc_init(void)
2333 {
2334 return register_pernet_subsys(&tcp4_net_ops);
2335 }
2336
2337 void tcp4_proc_exit(void)
2338 {
2339 unregister_pernet_subsys(&tcp4_net_ops);
2340 }
2341 #endif /* CONFIG_PROC_FS */
2342
2343 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2344 {
2345 struct iphdr *iph = ip_hdr(skb);
2346
2347 switch (skb->ip_summed) {
2348 case CHECKSUM_COMPLETE:
2349 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2350 skb->csum)) {
2351 skb->ip_summed = CHECKSUM_UNNECESSARY;
2352 break;
2353 }
2354
2355 /* fall through */
2356 case CHECKSUM_NONE:
2357 NAPI_GRO_CB(skb)->flush = 1;
2358 return NULL;
2359 }
2360
2361 return tcp_gro_receive(head, skb);
2362 }
2363 EXPORT_SYMBOL(tcp4_gro_receive);
2364
2365 int tcp4_gro_complete(struct sk_buff *skb)
2366 {
2367 struct iphdr *iph = ip_hdr(skb);
2368 struct tcphdr *th = tcp_hdr(skb);
2369
2370 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2371 iph->saddr, iph->daddr, 0);
2372 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2373
2374 return tcp_gro_complete(skb);
2375 }
2376 EXPORT_SYMBOL(tcp4_gro_complete);
2377
2378 struct proto tcp_prot = {
2379 .name = "TCP",
2380 .owner = THIS_MODULE,
2381 .close = tcp_close,
2382 .connect = tcp_v4_connect,
2383 .disconnect = tcp_disconnect,
2384 .accept = inet_csk_accept,
2385 .ioctl = tcp_ioctl,
2386 .init = tcp_v4_init_sock,
2387 .destroy = tcp_v4_destroy_sock,
2388 .shutdown = tcp_shutdown,
2389 .setsockopt = tcp_setsockopt,
2390 .getsockopt = tcp_getsockopt,
2391 .recvmsg = tcp_recvmsg,
2392 .backlog_rcv = tcp_v4_do_rcv,
2393 .hash = inet_hash,
2394 .unhash = inet_unhash,
2395 .get_port = inet_csk_get_port,
2396 .enter_memory_pressure = tcp_enter_memory_pressure,
2397 .sockets_allocated = &tcp_sockets_allocated,
2398 .orphan_count = &tcp_orphan_count,
2399 .memory_allocated = &tcp_memory_allocated,
2400 .memory_pressure = &tcp_memory_pressure,
2401 .sysctl_mem = sysctl_tcp_mem,
2402 .sysctl_wmem = sysctl_tcp_wmem,
2403 .sysctl_rmem = sysctl_tcp_rmem,
2404 .max_header = MAX_TCP_HEADER,
2405 .obj_size = sizeof(struct tcp_sock),
2406 .slab_flags = SLAB_DESTROY_BY_RCU,
2407 .twsk_prot = &tcp_timewait_sock_ops,
2408 .rsk_prot = &tcp_request_sock_ops,
2409 .h.hashinfo = &tcp_hashinfo,
2410 #ifdef CONFIG_COMPAT
2411 .compat_setsockopt = compat_tcp_setsockopt,
2412 .compat_getsockopt = compat_tcp_getsockopt,
2413 #endif
2414 };
2415
2416
2417 static int __net_init tcp_sk_init(struct net *net)
2418 {
2419 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2420 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2421 }
2422
2423 static void __net_exit tcp_sk_exit(struct net *net)
2424 {
2425 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2426 inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
2427 }
2428
2429 static struct pernet_operations __net_initdata tcp_sk_ops = {
2430 .init = tcp_sk_init,
2431 .exit = tcp_sk_exit,
2432 };
2433
2434 void __init tcp_v4_init(void)
2435 {
2436 inet_hashinfo_init(&tcp_hashinfo);
2437 if (register_pernet_subsys(&tcp_sk_ops))
2438 panic("Failed to create the TCP control socket.\n");
2439 }
2440
2441 EXPORT_SYMBOL(ipv4_specific);
2442 EXPORT_SYMBOL(tcp_hashinfo);
2443 EXPORT_SYMBOL(tcp_prot);
2444 EXPORT_SYMBOL(tcp_v4_conn_request);
2445 EXPORT_SYMBOL(tcp_v4_connect);
2446 EXPORT_SYMBOL(tcp_v4_do_rcv);
2447 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2448 EXPORT_SYMBOL(tcp_v4_send_check);
2449 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2450
2451 #ifdef CONFIG_PROC_FS
2452 EXPORT_SYMBOL(tcp_proc_register);
2453 EXPORT_SYMBOL(tcp_proc_unregister);
2454 #endif
2455 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2456
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