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[IPV4]: Use the {DEFINE|REF}_PROTO_INUSE infrastructure
[linux-2.6/mini2440.git] / net / ipv4 / tcp_ipv4.c
blobe9127cdced20a0c774b780eca0a1d32a7f41fdc0
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $
9 *
10 * IPv4 specific functions
11 *
12 *
13 * code split from:
14 * linux/ipv4/tcp.c
15 * linux/ipv4/tcp_input.c
16 * linux/ipv4/tcp_output.c
17 *
18 * See tcp.c for author information
19 *
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version
23 * 2 of the License, or (at your option) any later version.
24 */
25
26 /*
27 * Changes:
28 * David S. Miller : New socket lookup architecture.
29 * This code is dedicated to John Dyson.
30 * David S. Miller : Change semantics of established hash,
31 * half is devoted to TIME_WAIT sockets
32 * and the rest go in the other half.
33 * Andi Kleen : Add support for syncookies and fixed
34 * some bugs: ip options weren't passed to
35 * the TCP layer, missed a check for an
36 * ACK bit.
37 * Andi Kleen : Implemented fast path mtu discovery.
38 * Fixed many serious bugs in the
39 * request_sock handling and moved
40 * most of it into the af independent code.
41 * Added tail drop and some other bugfixes.
42 * Added new listen semantics.
43 * Mike McLagan : Routing by source
44 * Juan Jose Ciarlante: ip_dynaddr bits
45 * Andi Kleen: various fixes.
46 * Vitaly E. Lavrov : Transparent proxy revived after year
47 * coma.
48 * Andi Kleen : Fix new listen.
49 * Andi Kleen : Fix accept error reporting.
50 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
51 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
52 * a single port at the same time.
53 */
54
55
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64
65 #include <net/net_namespace.h>
66 #include <net/icmp.h>
67 #include <net/inet_hashtables.h>
68 #include <net/tcp.h>
69 #include <net/transp_v6.h>
70 #include <net/ipv6.h>
71 #include <net/inet_common.h>
72 #include <net/timewait_sock.h>
73 #include <net/xfrm.h>
74 #include <net/netdma.h>
75
76 #include <linux/inet.h>
77 #include <linux/ipv6.h>
78 #include <linux/stddef.h>
79 #include <linux/proc_fs.h>
80 #include <linux/seq_file.h>
81
82 #include <linux/crypto.h>
83 #include <linux/scatterlist.h>
84
85 int sysctl_tcp_tw_reuse __read_mostly;
86 int sysctl_tcp_low_latency __read_mostly;
87
88 /* Check TCP sequence numbers in ICMP packets. */
89 #define ICMP_MIN_LENGTH 8
90
91 /* Socket used for sending RSTs */
92 static struct socket *tcp_socket __read_mostly;
93
94 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
95
96 #ifdef CONFIG_TCP_MD5SIG
97 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
98 __be32 addr);
99 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
100 __be32 saddr, __be32 daddr,
101 struct tcphdr *th, int protocol,
102 int tcplen);
103 #endif
104
105 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
106 .lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
107 .lhash_users = ATOMIC_INIT(0),
108 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
109 };
110
111 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
112 {
113 return inet_csk_get_port(&tcp_hashinfo, sk, snum,
114 inet_csk_bind_conflict);
115 }
116
117 static void tcp_v4_hash(struct sock *sk)
118 {
119 inet_hash(&tcp_hashinfo, sk);
120 }
121
122 void tcp_unhash(struct sock *sk)
123 {
124 inet_unhash(&tcp_hashinfo, sk);
125 }
126
127 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
128 {
129 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
130 ip_hdr(skb)->saddr,
131 tcp_hdr(skb)->dest,
132 tcp_hdr(skb)->source);
133 }
134
135 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
136 {
137 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
138 struct tcp_sock *tp = tcp_sk(sk);
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (twp == NULL || (sysctl_tcp_tw_reuse &&
153 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
154 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
155 if (tp->write_seq == 0)
156 tp->write_seq = 1;
157 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
158 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
159 sock_hold(sktw);
160 return 1;
161 }
162
163 return 0;
164 }
165
166 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
167
168 /* This will initiate an outgoing connection. */
169 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
170 {
171 struct inet_sock *inet = inet_sk(sk);
172 struct tcp_sock *tp = tcp_sk(sk);
173 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
174 struct rtable *rt;
175 __be32 daddr, nexthop;
176 int tmp;
177 int err;
178
179 if (addr_len < sizeof(struct sockaddr_in))
180 return -EINVAL;
181
182 if (usin->sin_family != AF_INET)
183 return -EAFNOSUPPORT;
184
185 nexthop = daddr = usin->sin_addr.s_addr;
186 if (inet->opt && inet->opt->srr) {
187 if (!daddr)
188 return -EINVAL;
189 nexthop = inet->opt->faddr;
190 }
191
192 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
193 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
194 IPPROTO_TCP,
195 inet->sport, usin->sin_port, sk, 1);
196 if (tmp < 0) {
197 if (tmp == -ENETUNREACH)
198 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
199 return tmp;
200 }
201
202 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
203 ip_rt_put(rt);
204 return -ENETUNREACH;
205 }
206
207 if (!inet->opt || !inet->opt->srr)
208 daddr = rt->rt_dst;
209
210 if (!inet->saddr)
211 inet->saddr = rt->rt_src;
212 inet->rcv_saddr = inet->saddr;
213
214 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
215 /* Reset inherited state */
216 tp->rx_opt.ts_recent = 0;
217 tp->rx_opt.ts_recent_stamp = 0;
218 tp->write_seq = 0;
219 }
220
221 if (tcp_death_row.sysctl_tw_recycle &&
222 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
223 struct inet_peer *peer = rt_get_peer(rt);
224 /*
225 * VJ's idea. We save last timestamp seen from
226 * the destination in peer table, when entering state
227 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
228 * when trying new connection.
229 */
230 if (peer != NULL &&
231 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
232 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
233 tp->rx_opt.ts_recent = peer->tcp_ts;
234 }
235 }
236
237 inet->dport = usin->sin_port;
238 inet->daddr = daddr;
239
240 inet_csk(sk)->icsk_ext_hdr_len = 0;
241 if (inet->opt)
242 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
243
244 tp->rx_opt.mss_clamp = 536;
245
246 /* Socket identity is still unknown (sport may be zero).
247 * However we set state to SYN-SENT and not releasing socket
248 * lock select source port, enter ourselves into the hash tables and
249 * complete initialization after this.
250 */
251 tcp_set_state(sk, TCP_SYN_SENT);
252 err = inet_hash_connect(&tcp_death_row, sk);
253 if (err)
254 goto failure;
255
256 err = ip_route_newports(&rt, IPPROTO_TCP,
257 inet->sport, inet->dport, sk);
258 if (err)
259 goto failure;
260
261 /* OK, now commit destination to socket. */
262 sk->sk_gso_type = SKB_GSO_TCPV4;
263 sk_setup_caps(sk, &rt->u.dst);
264
265 if (!tp->write_seq)
266 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
267 inet->daddr,
268 inet->sport,
269 usin->sin_port);
270
271 inet->id = tp->write_seq ^ jiffies;
272
273 err = tcp_connect(sk);
274 rt = NULL;
275 if (err)
276 goto failure;
277
278 return 0;
279
280 failure:
281 /*
282 * This unhashes the socket and releases the local port,
283 * if necessary.
284 */
285 tcp_set_state(sk, TCP_CLOSE);
286 ip_rt_put(rt);
287 sk->sk_route_caps = 0;
288 inet->dport = 0;
289 return err;
290 }
291
292 /*
293 * This routine does path mtu discovery as defined in RFC1191.
294 */
295 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
296 {
297 struct dst_entry *dst;
298 struct inet_sock *inet = inet_sk(sk);
299
300 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
301 * send out by Linux are always <576bytes so they should go through
302 * unfragmented).
303 */
304 if (sk->sk_state == TCP_LISTEN)
305 return;
306
307 /* We don't check in the destentry if pmtu discovery is forbidden
308 * on this route. We just assume that no packet_to_big packets
309 * are send back when pmtu discovery is not active.
310 * There is a small race when the user changes this flag in the
311 * route, but I think that's acceptable.
312 */
313 if ((dst = __sk_dst_check(sk, 0)) == NULL)
314 return;
315
316 dst->ops->update_pmtu(dst, mtu);
317
318 /* Something is about to be wrong... Remember soft error
319 * for the case, if this connection will not able to recover.
320 */
321 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
322 sk->sk_err_soft = EMSGSIZE;
323
324 mtu = dst_mtu(dst);
325
326 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
327 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
328 tcp_sync_mss(sk, mtu);
329
330 /* Resend the TCP packet because it's
331 * clear that the old packet has been
332 * dropped. This is the new "fast" path mtu
333 * discovery.
334 */
335 tcp_simple_retransmit(sk);
336 } /* else let the usual retransmit timer handle it */
337 }
338
339 /*
340 * This routine is called by the ICMP module when it gets some
341 * sort of error condition. If err < 0 then the socket should
342 * be closed and the error returned to the user. If err > 0
343 * it's just the icmp type << 8 | icmp code. After adjustment
344 * header points to the first 8 bytes of the tcp header. We need
345 * to find the appropriate port.
346 *
347 * The locking strategy used here is very "optimistic". When
348 * someone else accesses the socket the ICMP is just dropped
349 * and for some paths there is no check at all.
350 * A more general error queue to queue errors for later handling
351 * is probably better.
352 *
353 */
354
355 void tcp_v4_err(struct sk_buff *skb, u32 info)
356 {
357 struct iphdr *iph = (struct iphdr *)skb->data;
358 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
359 struct tcp_sock *tp;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(skb)->type;
362 const int code = icmp_hdr(skb)->code;
363 struct sock *sk;
364 __u32 seq;
365 int err;
366
367 if (skb->len < (iph->ihl << 2) + 8) {
368 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
369 return;
370 }
371
372 sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr,
373 th->source, inet_iif(skb));
374 if (!sk) {
375 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
376 return;
377 }
378 if (sk->sk_state == TCP_TIME_WAIT) {
379 inet_twsk_put(inet_twsk(sk));
380 return;
381 }
382
383 bh_lock_sock(sk);
384 /* If too many ICMPs get dropped on busy
385 * servers this needs to be solved differently.
386 */
387 if (sock_owned_by_user(sk))
388 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
389
390 if (sk->sk_state == TCP_CLOSE)
391 goto out;
392
393 tp = tcp_sk(sk);
394 seq = ntohl(th->seq);
395 if (sk->sk_state != TCP_LISTEN &&
396 !between(seq, tp->snd_una, tp->snd_nxt)) {
397 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
398 goto out;
399 }
400
401 switch (type) {
402 case ICMP_SOURCE_QUENCH:
403 /* Just silently ignore these. */
404 goto out;
405 case ICMP_PARAMETERPROB:
406 err = EPROTO;
407 break;
408 case ICMP_DEST_UNREACH:
409 if (code > NR_ICMP_UNREACH)
410 goto out;
411
412 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
413 if (!sock_owned_by_user(sk))
414 do_pmtu_discovery(sk, iph, info);
415 goto out;
416 }
417
418 err = icmp_err_convert[code].errno;
419 break;
420 case ICMP_TIME_EXCEEDED:
421 err = EHOSTUNREACH;
422 break;
423 default:
424 goto out;
425 }
426
427 switch (sk->sk_state) {
428 struct request_sock *req, **prev;
429 case TCP_LISTEN:
430 if (sock_owned_by_user(sk))
431 goto out;
432
433 req = inet_csk_search_req(sk, &prev, th->dest,
434 iph->daddr, iph->saddr);
435 if (!req)
436 goto out;
437
438 /* ICMPs are not backlogged, hence we cannot get
439 an established socket here.
440 */
441 BUG_TRAP(!req->sk);
442
443 if (seq != tcp_rsk(req)->snt_isn) {
444 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
445 goto out;
446 }
447
448 /*
449 * Still in SYN_RECV, just remove it silently.
450 * There is no good way to pass the error to the newly
451 * created socket, and POSIX does not want network
452 * errors returned from accept().
453 */
454 inet_csk_reqsk_queue_drop(sk, req, prev);
455 goto out;
456
457 case TCP_SYN_SENT:
458 case TCP_SYN_RECV: /* Cannot happen.
459 It can f.e. if SYNs crossed.
460 */
461 if (!sock_owned_by_user(sk)) {
462 sk->sk_err = err;
463
464 sk->sk_error_report(sk);
465
466 tcp_done(sk);
467 } else {
468 sk->sk_err_soft = err;
469 }
470 goto out;
471 }
472
473 /* If we've already connected we will keep trying
474 * until we time out, or the user gives up.
475 *
476 * rfc1122 4.2.3.9 allows to consider as hard errors
477 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
478 * but it is obsoleted by pmtu discovery).
479 *
480 * Note, that in modern internet, where routing is unreliable
481 * and in each dark corner broken firewalls sit, sending random
482 * errors ordered by their masters even this two messages finally lose
483 * their original sense (even Linux sends invalid PORT_UNREACHs)
484 *
485 * Now we are in compliance with RFCs.
486 * --ANK (980905)
487 */
488
489 inet = inet_sk(sk);
490 if (!sock_owned_by_user(sk) && inet->recverr) {
491 sk->sk_err = err;
492 sk->sk_error_report(sk);
493 } else { /* Only an error on timeout */
494 sk->sk_err_soft = err;
495 }
496
497 out:
498 bh_unlock_sock(sk);
499 sock_put(sk);
500 }
501
502 /* This routine computes an IPv4 TCP checksum. */
503 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
504 {
505 struct inet_sock *inet = inet_sk(sk);
506 struct tcphdr *th = tcp_hdr(skb);
507
508 if (skb->ip_summed == CHECKSUM_PARTIAL) {
509 th->check = ~tcp_v4_check(len, inet->saddr,
510 inet->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 } else {
514 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
515 csum_partial((char *)th,
516 th->doff << 2,
517 skb->csum));
518 }
519 }
520
521 int tcp_v4_gso_send_check(struct sk_buff *skb)
522 {
523 const struct iphdr *iph;
524 struct tcphdr *th;
525
526 if (!pskb_may_pull(skb, sizeof(*th)))
527 return -EINVAL;
528
529 iph = ip_hdr(skb);
530 th = tcp_hdr(skb);
531
532 th->check = 0;
533 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
534 skb->csum_start = skb_transport_header(skb) - skb->head;
535 skb->csum_offset = offsetof(struct tcphdr, check);
536 skb->ip_summed = CHECKSUM_PARTIAL;
537 return 0;
538 }
539
540 /*
541 * This routine will send an RST to the other tcp.
542 *
543 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
544 * for reset.
545 * Answer: if a packet caused RST, it is not for a socket
546 * existing in our system, if it is matched to a socket,
547 * it is just duplicate segment or bug in other side's TCP.
548 * So that we build reply only basing on parameters
549 * arrived with segment.
550 * Exception: precedence violation. We do not implement it in any case.
551 */
552
553 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
554 {
555 struct tcphdr *th = tcp_hdr(skb);
556 struct {
557 struct tcphdr th;
558 #ifdef CONFIG_TCP_MD5SIG
559 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
560 #endif
561 } rep;
562 struct ip_reply_arg arg;
563 #ifdef CONFIG_TCP_MD5SIG
564 struct tcp_md5sig_key *key;
565 #endif
566
567 /* Never send a reset in response to a reset. */
568 if (th->rst)
569 return;
570
571 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
572 return;
573
574 /* Swap the send and the receive. */
575 memset(&rep, 0, sizeof(rep));
576 rep.th.dest = th->source;
577 rep.th.source = th->dest;
578 rep.th.doff = sizeof(struct tcphdr) / 4;
579 rep.th.rst = 1;
580
581 if (th->ack) {
582 rep.th.seq = th->ack_seq;
583 } else {
584 rep.th.ack = 1;
585 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
586 skb->len - (th->doff << 2));
587 }
588
589 memset(&arg, 0, sizeof(arg));
590 arg.iov[0].iov_base = (unsigned char *)&rep;
591 arg.iov[0].iov_len = sizeof(rep.th);
592
593 #ifdef CONFIG_TCP_MD5SIG
594 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
595 if (key) {
596 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
597 (TCPOPT_NOP << 16) |
598 (TCPOPT_MD5SIG << 8) |
599 TCPOLEN_MD5SIG);
600 /* Update length and the length the header thinks exists */
601 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
602 rep.th.doff = arg.iov[0].iov_len / 4;
603
604 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
605 key,
606 ip_hdr(skb)->daddr,
607 ip_hdr(skb)->saddr,
608 &rep.th, IPPROTO_TCP,
609 arg.iov[0].iov_len);
610 }
611 #endif
612 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
613 ip_hdr(skb)->saddr, /* XXX */
614 sizeof(struct tcphdr), IPPROTO_TCP, 0);
615 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
616
617 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
618
619 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
620 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
621 }
622
623 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
624 outside socket context is ugly, certainly. What can I do?
625 */
626
627 static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
628 struct sk_buff *skb, u32 seq, u32 ack,
629 u32 win, u32 ts)
630 {
631 struct tcphdr *th = tcp_hdr(skb);
632 struct {
633 struct tcphdr th;
634 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
635 #ifdef CONFIG_TCP_MD5SIG
636 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
637 #endif
638 ];
639 } rep;
640 struct ip_reply_arg arg;
641 #ifdef CONFIG_TCP_MD5SIG
642 struct tcp_md5sig_key *key;
643 struct tcp_md5sig_key tw_key;
644 #endif
645
646 memset(&rep.th, 0, sizeof(struct tcphdr));
647 memset(&arg, 0, sizeof(arg));
648
649 arg.iov[0].iov_base = (unsigned char *)&rep;
650 arg.iov[0].iov_len = sizeof(rep.th);
651 if (ts) {
652 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
653 (TCPOPT_TIMESTAMP << 8) |
654 TCPOLEN_TIMESTAMP);
655 rep.opt[1] = htonl(tcp_time_stamp);
656 rep.opt[2] = htonl(ts);
657 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
658 }
659
660 /* Swap the send and the receive. */
661 rep.th.dest = th->source;
662 rep.th.source = th->dest;
663 rep.th.doff = arg.iov[0].iov_len / 4;
664 rep.th.seq = htonl(seq);
665 rep.th.ack_seq = htonl(ack);
666 rep.th.ack = 1;
667 rep.th.window = htons(win);
668
669 #ifdef CONFIG_TCP_MD5SIG
670 /*
671 * The SKB holds an imcoming packet, but may not have a valid ->sk
672 * pointer. This is especially the case when we're dealing with a
673 * TIME_WAIT ack, because the sk structure is long gone, and only
674 * the tcp_timewait_sock remains. So the md5 key is stashed in that
675 * structure, and we use it in preference. I believe that (twsk ||
676 * skb->sk) holds true, but we program defensively.
677 */
678 if (!twsk && skb->sk) {
679 key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
680 } else if (twsk && twsk->tw_md5_keylen) {
681 tw_key.key = twsk->tw_md5_key;
682 tw_key.keylen = twsk->tw_md5_keylen;
683 key = &tw_key;
684 } else
685 key = NULL;
686
687 if (key) {
688 int offset = (ts) ? 3 : 0;
689
690 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
691 (TCPOPT_NOP << 16) |
692 (TCPOPT_MD5SIG << 8) |
693 TCPOLEN_MD5SIG);
694 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
695 rep.th.doff = arg.iov[0].iov_len/4;
696
697 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
698 key,
699 ip_hdr(skb)->daddr,
700 ip_hdr(skb)->saddr,
701 &rep.th, IPPROTO_TCP,
702 arg.iov[0].iov_len);
703 }
704 #endif
705 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
706 ip_hdr(skb)->saddr, /* XXX */
707 arg.iov[0].iov_len, IPPROTO_TCP, 0);
708 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
709 if (twsk)
710 arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
711
712 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
713
714 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
715 }
716
717 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
718 {
719 struct inet_timewait_sock *tw = inet_twsk(sk);
720 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
721
722 tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
723 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
724 tcptw->tw_ts_recent);
725
726 inet_twsk_put(tw);
727 }
728
729 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
730 struct request_sock *req)
731 {
732 tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
733 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
734 req->ts_recent);
735 }
736
737 /*
738 * Send a SYN-ACK after having received an ACK.
739 * This still operates on a request_sock only, not on a big
740 * socket.
741 */
742 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
743 struct dst_entry *dst)
744 {
745 const struct inet_request_sock *ireq = inet_rsk(req);
746 int err = -1;
747 struct sk_buff * skb;
748
749 /* First, grab a route. */
750 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
751 goto out;
752
753 skb = tcp_make_synack(sk, dst, req);
754
755 if (skb) {
756 struct tcphdr *th = tcp_hdr(skb);
757
758 th->check = tcp_v4_check(skb->len,
759 ireq->loc_addr,
760 ireq->rmt_addr,
761 csum_partial((char *)th, skb->len,
762 skb->csum));
763
764 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
765 ireq->rmt_addr,
766 ireq->opt);
767 err = net_xmit_eval(err);
768 }
769
770 out:
771 dst_release(dst);
772 return err;
773 }
774
775 /*
776 * IPv4 request_sock destructor.
777 */
778 static void tcp_v4_reqsk_destructor(struct request_sock *req)
779 {
780 kfree(inet_rsk(req)->opt);
781 }
782
783 #ifdef CONFIG_SYN_COOKIES
784 static void syn_flood_warning(struct sk_buff *skb)
785 {
786 static unsigned long warntime;
787
788 if (time_after(jiffies, (warntime + HZ * 60))) {
789 warntime = jiffies;
790 printk(KERN_INFO
791 "possible SYN flooding on port %d. Sending cookies.\n",
792 ntohs(tcp_hdr(skb)->dest));
793 }
794 }
795 #endif
796
797 /*
798 * Save and compile IPv4 options into the request_sock if needed.
799 */
800 static struct ip_options *tcp_v4_save_options(struct sock *sk,
801 struct sk_buff *skb)
802 {
803 struct ip_options *opt = &(IPCB(skb)->opt);
804 struct ip_options *dopt = NULL;
805
806 if (opt && opt->optlen) {
807 int opt_size = optlength(opt);
808 dopt = kmalloc(opt_size, GFP_ATOMIC);
809 if (dopt) {
810 if (ip_options_echo(dopt, skb)) {
811 kfree(dopt);
812 dopt = NULL;
813 }
814 }
815 }
816 return dopt;
817 }
818
819 #ifdef CONFIG_TCP_MD5SIG
820 /*
821 * RFC2385 MD5 checksumming requires a mapping of
822 * IP address->MD5 Key.
823 * We need to maintain these in the sk structure.
824 */
825
826 /* Find the Key structure for an address. */
827 static struct tcp_md5sig_key *
828 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
829 {
830 struct tcp_sock *tp = tcp_sk(sk);
831 int i;
832
833 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
834 return NULL;
835 for (i = 0; i < tp->md5sig_info->entries4; i++) {
836 if (tp->md5sig_info->keys4[i].addr == addr)
837 return &tp->md5sig_info->keys4[i].base;
838 }
839 return NULL;
840 }
841
842 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
843 struct sock *addr_sk)
844 {
845 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
846 }
847
848 EXPORT_SYMBOL(tcp_v4_md5_lookup);
849
850 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
851 struct request_sock *req)
852 {
853 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
854 }
855
856 /* This can be called on a newly created socket, from other files */
857 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
858 u8 *newkey, u8 newkeylen)
859 {
860 /* Add Key to the list */
861 struct tcp_md5sig_key *key;
862 struct tcp_sock *tp = tcp_sk(sk);
863 struct tcp4_md5sig_key *keys;
864
865 key = tcp_v4_md5_do_lookup(sk, addr);
866 if (key) {
867 /* Pre-existing entry - just update that one. */
868 kfree(key->key);
869 key->key = newkey;
870 key->keylen = newkeylen;
871 } else {
872 struct tcp_md5sig_info *md5sig;
873
874 if (!tp->md5sig_info) {
875 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
876 GFP_ATOMIC);
877 if (!tp->md5sig_info) {
878 kfree(newkey);
879 return -ENOMEM;
880 }
881 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
882 }
883 if (tcp_alloc_md5sig_pool() == NULL) {
884 kfree(newkey);
885 return -ENOMEM;
886 }
887 md5sig = tp->md5sig_info;
888
889 if (md5sig->alloced4 == md5sig->entries4) {
890 keys = kmalloc((sizeof(*keys) *
891 (md5sig->entries4 + 1)), GFP_ATOMIC);
892 if (!keys) {
893 kfree(newkey);
894 tcp_free_md5sig_pool();
895 return -ENOMEM;
896 }
897
898 if (md5sig->entries4)
899 memcpy(keys, md5sig->keys4,
900 sizeof(*keys) * md5sig->entries4);
901
902 /* Free old key list, and reference new one */
903 if (md5sig->keys4)
904 kfree(md5sig->keys4);
905 md5sig->keys4 = keys;
906 md5sig->alloced4++;
907 }
908 md5sig->entries4++;
909 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
910 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
911 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
912 }
913 return 0;
914 }
915
916 EXPORT_SYMBOL(tcp_v4_md5_do_add);
917
918 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
919 u8 *newkey, u8 newkeylen)
920 {
921 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
922 newkey, newkeylen);
923 }
924
925 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
926 {
927 struct tcp_sock *tp = tcp_sk(sk);
928 int i;
929
930 for (i = 0; i < tp->md5sig_info->entries4; i++) {
931 if (tp->md5sig_info->keys4[i].addr == addr) {
932 /* Free the key */
933 kfree(tp->md5sig_info->keys4[i].base.key);
934 tp->md5sig_info->entries4--;
935
936 if (tp->md5sig_info->entries4 == 0) {
937 kfree(tp->md5sig_info->keys4);
938 tp->md5sig_info->keys4 = NULL;
939 tp->md5sig_info->alloced4 = 0;
940 } else if (tp->md5sig_info->entries4 != i) {
941 /* Need to do some manipulation */
942 memcpy(&tp->md5sig_info->keys4[i],
943 &tp->md5sig_info->keys4[i+1],
944 (tp->md5sig_info->entries4 - i) *
945 sizeof(struct tcp4_md5sig_key));
946 }
947 tcp_free_md5sig_pool();
948 return 0;
949 }
950 }
951 return -ENOENT;
952 }
953
954 EXPORT_SYMBOL(tcp_v4_md5_do_del);
955
956 static void tcp_v4_clear_md5_list(struct sock *sk)
957 {
958 struct tcp_sock *tp = tcp_sk(sk);
959
960 /* Free each key, then the set of key keys,
961 * the crypto element, and then decrement our
962 * hold on the last resort crypto.
963 */
964 if (tp->md5sig_info->entries4) {
965 int i;
966 for (i = 0; i < tp->md5sig_info->entries4; i++)
967 kfree(tp->md5sig_info->keys4[i].base.key);
968 tp->md5sig_info->entries4 = 0;
969 tcp_free_md5sig_pool();
970 }
971 if (tp->md5sig_info->keys4) {
972 kfree(tp->md5sig_info->keys4);
973 tp->md5sig_info->keys4 = NULL;
974 tp->md5sig_info->alloced4 = 0;
975 }
976 }
977
978 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
979 int optlen)
980 {
981 struct tcp_md5sig cmd;
982 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
983 u8 *newkey;
984
985 if (optlen < sizeof(cmd))
986 return -EINVAL;
987
988 if (copy_from_user(&cmd, optval, sizeof(cmd)))
989 return -EFAULT;
990
991 if (sin->sin_family != AF_INET)
992 return -EINVAL;
993
994 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
995 if (!tcp_sk(sk)->md5sig_info)
996 return -ENOENT;
997 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
998 }
999
1000 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1001 return -EINVAL;
1002
1003 if (!tcp_sk(sk)->md5sig_info) {
1004 struct tcp_sock *tp = tcp_sk(sk);
1005 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
1006
1007 if (!p)
1008 return -EINVAL;
1009
1010 tp->md5sig_info = p;
1011 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1012 }
1013
1014 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1015 if (!newkey)
1016 return -ENOMEM;
1017 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1018 newkey, cmd.tcpm_keylen);
1019 }
1020
1021 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1022 __be32 saddr, __be32 daddr,
1023 struct tcphdr *th, int protocol,
1024 int tcplen)
1025 {
1026 struct scatterlist sg[4];
1027 __u16 data_len;
1028 int block = 0;
1029 __sum16 old_checksum;
1030 struct tcp_md5sig_pool *hp;
1031 struct tcp4_pseudohdr *bp;
1032 struct hash_desc *desc;
1033 int err;
1034 unsigned int nbytes = 0;
1035
1036 /*
1037 * Okay, so RFC2385 is turned on for this connection,
1038 * so we need to generate the MD5 hash for the packet now.
1039 */
1040
1041 hp = tcp_get_md5sig_pool();
1042 if (!hp)
1043 goto clear_hash_noput;
1044
1045 bp = &hp->md5_blk.ip4;
1046 desc = &hp->md5_desc;
1047
1048 /*
1049 * 1. the TCP pseudo-header (in the order: source IP address,
1050 * destination IP address, zero-padded protocol number, and
1051 * segment length)
1052 */
1053 bp->saddr = saddr;
1054 bp->daddr = daddr;
1055 bp->pad = 0;
1056 bp->protocol = protocol;
1057 bp->len = htons(tcplen);
1058
1059 sg_init_table(sg, 4);
1060
1061 sg_set_buf(&sg[block++], bp, sizeof(*bp));
1062 nbytes += sizeof(*bp);
1063
1064 /* 2. the TCP header, excluding options, and assuming a
1065 * checksum of zero/
1066 */
1067 old_checksum = th->check;
1068 th->check = 0;
1069 sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
1070 nbytes += sizeof(struct tcphdr);
1071
1072 /* 3. the TCP segment data (if any) */
1073 data_len = tcplen - (th->doff << 2);
1074 if (data_len > 0) {
1075 unsigned char *data = (unsigned char *)th + (th->doff << 2);
1076 sg_set_buf(&sg[block++], data, data_len);
1077 nbytes += data_len;
1078 }
1079
1080 /* 4. an independently-specified key or password, known to both
1081 * TCPs and presumably connection-specific
1082 */
1083 sg_set_buf(&sg[block++], key->key, key->keylen);
1084 nbytes += key->keylen;
1085
1086 sg_mark_end(&sg[block - 1]);
1087
1088 /* Now store the Hash into the packet */
1089 err = crypto_hash_init(desc);
1090 if (err)
1091 goto clear_hash;
1092 err = crypto_hash_update(desc, sg, nbytes);
1093 if (err)
1094 goto clear_hash;
1095 err = crypto_hash_final(desc, md5_hash);
1096 if (err)
1097 goto clear_hash;
1098
1099 /* Reset header, and free up the crypto */
1100 tcp_put_md5sig_pool();
1101 th->check = old_checksum;
1102
1103 out:
1104 return 0;
1105 clear_hash:
1106 tcp_put_md5sig_pool();
1107 clear_hash_noput:
1108 memset(md5_hash, 0, 16);
1109 goto out;
1110 }
1111
1112 int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1113 struct sock *sk,
1114 struct dst_entry *dst,
1115 struct request_sock *req,
1116 struct tcphdr *th, int protocol,
1117 int tcplen)
1118 {
1119 __be32 saddr, daddr;
1120
1121 if (sk) {
1122 saddr = inet_sk(sk)->saddr;
1123 daddr = inet_sk(sk)->daddr;
1124 } else {
1125 struct rtable *rt = (struct rtable *)dst;
1126 BUG_ON(!rt);
1127 saddr = rt->rt_src;
1128 daddr = rt->rt_dst;
1129 }
1130 return tcp_v4_do_calc_md5_hash(md5_hash, key,
1131 saddr, daddr,
1132 th, protocol, tcplen);
1133 }
1134
1135 EXPORT_SYMBOL(tcp_v4_calc_md5_hash);
1136
1137 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1138 {
1139 /*
1140 * This gets called for each TCP segment that arrives
1141 * so we want to be efficient.
1142 * We have 3 drop cases:
1143 * o No MD5 hash and one expected.
1144 * o MD5 hash and we're not expecting one.
1145 * o MD5 hash and its wrong.
1146 */
1147 __u8 *hash_location = NULL;
1148 struct tcp_md5sig_key *hash_expected;
1149 const struct iphdr *iph = ip_hdr(skb);
1150 struct tcphdr *th = tcp_hdr(skb);
1151 int length = (th->doff << 2) - sizeof(struct tcphdr);
1152 int genhash;
1153 unsigned char *ptr;
1154 unsigned char newhash[16];
1155
1156 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1157
1158 /*
1159 * If the TCP option length is less than the TCP_MD5SIG
1160 * option length, then we can shortcut
1161 */
1162 if (length < TCPOLEN_MD5SIG) {
1163 if (hash_expected)
1164 return 1;
1165 else
1166 return 0;
1167 }
1168
1169 /* Okay, we can't shortcut - we have to grub through the options */
1170 ptr = (unsigned char *)(th + 1);
1171 while (length > 0) {
1172 int opcode = *ptr++;
1173 int opsize;
1174
1175 switch (opcode) {
1176 case TCPOPT_EOL:
1177 goto done_opts;
1178 case TCPOPT_NOP:
1179 length--;
1180 continue;
1181 default:
1182 opsize = *ptr++;
1183 if (opsize < 2)
1184 goto done_opts;
1185 if (opsize > length)
1186 goto done_opts;
1187
1188 if (opcode == TCPOPT_MD5SIG) {
1189 hash_location = ptr;
1190 goto done_opts;
1191 }
1192 }
1193 ptr += opsize-2;
1194 length -= opsize;
1195 }
1196 done_opts:
1197 /* We've parsed the options - do we have a hash? */
1198 if (!hash_expected && !hash_location)
1199 return 0;
1200
1201 if (hash_expected && !hash_location) {
1202 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
1203 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1204 NIPQUAD(iph->saddr), ntohs(th->source),
1205 NIPQUAD(iph->daddr), ntohs(th->dest));
1206 return 1;
1207 }
1208
1209 if (!hash_expected && hash_location) {
1210 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
1211 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1212 NIPQUAD(iph->saddr), ntohs(th->source),
1213 NIPQUAD(iph->daddr), ntohs(th->dest));
1214 return 1;
1215 }
1216
1217 /* Okay, so this is hash_expected and hash_location -
1218 * so we need to calculate the checksum.
1219 */
1220 genhash = tcp_v4_do_calc_md5_hash(newhash,
1221 hash_expected,
1222 iph->saddr, iph->daddr,
1223 th, sk->sk_protocol,
1224 skb->len);
1225
1226 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1227 if (net_ratelimit()) {
1228 printk(KERN_INFO "MD5 Hash failed for "
1229 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
1230 NIPQUAD(iph->saddr), ntohs(th->source),
1231 NIPQUAD(iph->daddr), ntohs(th->dest),
1232 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1233 }
1234 return 1;
1235 }
1236 return 0;
1237 }
1238
1239 #endif
1240
1241 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1242 .family = PF_INET,
1243 .obj_size = sizeof(struct tcp_request_sock),
1244 .rtx_syn_ack = tcp_v4_send_synack,
1245 .send_ack = tcp_v4_reqsk_send_ack,
1246 .destructor = tcp_v4_reqsk_destructor,
1247 .send_reset = tcp_v4_send_reset,
1248 };
1249
1250 #ifdef CONFIG_TCP_MD5SIG
1251 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1252 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1253 };
1254 #endif
1255
1256 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1257 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1258 .twsk_unique = tcp_twsk_unique,
1259 .twsk_destructor= tcp_twsk_destructor,
1260 };
1261
1262 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1263 {
1264 struct inet_request_sock *ireq;
1265 struct tcp_options_received tmp_opt;
1266 struct request_sock *req;
1267 __be32 saddr = ip_hdr(skb)->saddr;
1268 __be32 daddr = ip_hdr(skb)->daddr;
1269 __u32 isn = TCP_SKB_CB(skb)->when;
1270 struct dst_entry *dst = NULL;
1271 #ifdef CONFIG_SYN_COOKIES
1272 int want_cookie = 0;
1273 #else
1274 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1275 #endif
1276
1277 /* Never answer to SYNs send to broadcast or multicast */
1278 if (((struct rtable *)skb->dst)->rt_flags &
1279 (RTCF_BROADCAST | RTCF_MULTICAST))
1280 goto drop;
1281
1282 /* TW buckets are converted to open requests without
1283 * limitations, they conserve resources and peer is
1284 * evidently real one.
1285 */
1286 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1287 #ifdef CONFIG_SYN_COOKIES
1288 if (sysctl_tcp_syncookies) {
1289 want_cookie = 1;
1290 } else
1291 #endif
1292 goto drop;
1293 }
1294
1295 /* Accept backlog is full. If we have already queued enough
1296 * of warm entries in syn queue, drop request. It is better than
1297 * clogging syn queue with openreqs with exponentially increasing
1298 * timeout.
1299 */
1300 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1301 goto drop;
1302
1303 req = reqsk_alloc(&tcp_request_sock_ops);
1304 if (!req)
1305 goto drop;
1306
1307 #ifdef CONFIG_TCP_MD5SIG
1308 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1309 #endif
1310
1311 tcp_clear_options(&tmp_opt);
1312 tmp_opt.mss_clamp = 536;
1313 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1314
1315 tcp_parse_options(skb, &tmp_opt, 0);
1316
1317 if (want_cookie) {
1318 tcp_clear_options(&tmp_opt);
1319 tmp_opt.saw_tstamp = 0;
1320 }
1321
1322 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1323 /* Some OSes (unknown ones, but I see them on web server, which
1324 * contains information interesting only for windows'
1325 * users) do not send their stamp in SYN. It is easy case.
1326 * We simply do not advertise TS support.
1327 */
1328 tmp_opt.saw_tstamp = 0;
1329 tmp_opt.tstamp_ok = 0;
1330 }
1331 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1332
1333 tcp_openreq_init(req, &tmp_opt, skb);
1334
1335 if (security_inet_conn_request(sk, skb, req))
1336 goto drop_and_free;
1337
1338 ireq = inet_rsk(req);
1339 ireq->loc_addr = daddr;
1340 ireq->rmt_addr = saddr;
1341 ireq->opt = tcp_v4_save_options(sk, skb);
1342 if (!want_cookie)
1343 TCP_ECN_create_request(req, tcp_hdr(skb));
1344
1345 if (want_cookie) {
1346 #ifdef CONFIG_SYN_COOKIES
1347 syn_flood_warning(skb);
1348 #endif
1349 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1350 } else if (!isn) {
1351 struct inet_peer *peer = NULL;
1352
1353 /* VJ's idea. We save last timestamp seen
1354 * from the destination in peer table, when entering
1355 * state TIME-WAIT, and check against it before
1356 * accepting new connection request.
1357 *
1358 * If "isn" is not zero, this request hit alive
1359 * timewait bucket, so that all the necessary checks
1360 * are made in the function processing timewait state.
1361 */
1362 if (tmp_opt.saw_tstamp &&
1363 tcp_death_row.sysctl_tw_recycle &&
1364 (dst = inet_csk_route_req(sk, req)) != NULL &&
1365 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1366 peer->v4daddr == saddr) {
1367 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1368 (s32)(peer->tcp_ts - req->ts_recent) >
1369 TCP_PAWS_WINDOW) {
1370 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1371 dst_release(dst);
1372 goto drop_and_free;
1373 }
1374 }
1375 /* Kill the following clause, if you dislike this way. */
1376 else if (!sysctl_tcp_syncookies &&
1377 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1378 (sysctl_max_syn_backlog >> 2)) &&
1379 (!peer || !peer->tcp_ts_stamp) &&
1380 (!dst || !dst_metric(dst, RTAX_RTT))) {
1381 /* Without syncookies last quarter of
1382 * backlog is filled with destinations,
1383 * proven to be alive.
1384 * It means that we continue to communicate
1385 * to destinations, already remembered
1386 * to the moment of synflood.
1387 */
1388 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
1389 "request from %u.%u.%u.%u/%u\n",
1390 NIPQUAD(saddr),
1391 ntohs(tcp_hdr(skb)->source));
1392 dst_release(dst);
1393 goto drop_and_free;
1394 }
1395
1396 isn = tcp_v4_init_sequence(skb);
1397 }
1398 tcp_rsk(req)->snt_isn = isn;
1399
1400 if (tcp_v4_send_synack(sk, req, dst))
1401 goto drop_and_free;
1402
1403 if (want_cookie) {
1404 reqsk_free(req);
1405 } else {
1406 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1407 }
1408 return 0;
1409
1410 drop_and_free:
1411 reqsk_free(req);
1412 drop:
1413 return 0;
1414 }
1415
1416
1417 /*
1418 * The three way handshake has completed - we got a valid synack -
1419 * now create the new socket.
1420 */
1421 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1422 struct request_sock *req,
1423 struct dst_entry *dst)
1424 {
1425 struct inet_request_sock *ireq;
1426 struct inet_sock *newinet;
1427 struct tcp_sock *newtp;
1428 struct sock *newsk;
1429 #ifdef CONFIG_TCP_MD5SIG
1430 struct tcp_md5sig_key *key;
1431 #endif
1432
1433 if (sk_acceptq_is_full(sk))
1434 goto exit_overflow;
1435
1436 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1437 goto exit;
1438
1439 newsk = tcp_create_openreq_child(sk, req, skb);
1440 if (!newsk)
1441 goto exit;
1442
1443 newsk->sk_gso_type = SKB_GSO_TCPV4;
1444 sk_setup_caps(newsk, dst);
1445
1446 newtp = tcp_sk(newsk);
1447 newinet = inet_sk(newsk);
1448 ireq = inet_rsk(req);
1449 newinet->daddr = ireq->rmt_addr;
1450 newinet->rcv_saddr = ireq->loc_addr;
1451 newinet->saddr = ireq->loc_addr;
1452 newinet->opt = ireq->opt;
1453 ireq->opt = NULL;
1454 newinet->mc_index = inet_iif(skb);
1455 newinet->mc_ttl = ip_hdr(skb)->ttl;
1456 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1457 if (newinet->opt)
1458 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1459 newinet->id = newtp->write_seq ^ jiffies;
1460
1461 tcp_mtup_init(newsk);
1462 tcp_sync_mss(newsk, dst_mtu(dst));
1463 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1464 tcp_initialize_rcv_mss(newsk);
1465
1466 #ifdef CONFIG_TCP_MD5SIG
1467 /* Copy over the MD5 key from the original socket */
1468 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1469 /*
1470 * We're using one, so create a matching key
1471 * on the newsk structure. If we fail to get
1472 * memory, then we end up not copying the key
1473 * across. Shucks.
1474 */
1475 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1476 if (newkey != NULL)
1477 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1478 newkey, key->keylen);
1479 }
1480 #endif
1481
1482 __inet_hash(&tcp_hashinfo, newsk, 0);
1483 __inet_inherit_port(&tcp_hashinfo, sk, newsk);
1484
1485 return newsk;
1486
1487 exit_overflow:
1488 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1489 exit:
1490 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1491 dst_release(dst);
1492 return NULL;
1493 }
1494
1495 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1496 {
1497 struct tcphdr *th = tcp_hdr(skb);
1498 const struct iphdr *iph = ip_hdr(skb);
1499 struct sock *nsk;
1500 struct request_sock **prev;
1501 /* Find possible connection requests. */
1502 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1503 iph->saddr, iph->daddr);
1504 if (req)
1505 return tcp_check_req(sk, skb, req, prev);
1506
1507 nsk = inet_lookup_established(&tcp_hashinfo, iph->saddr, th->source,
1508 iph->daddr, th->dest, inet_iif(skb));
1509
1510 if (nsk) {
1511 if (nsk->sk_state != TCP_TIME_WAIT) {
1512 bh_lock_sock(nsk);
1513 return nsk;
1514 }
1515 inet_twsk_put(inet_twsk(nsk));
1516 return NULL;
1517 }
1518
1519 #ifdef CONFIG_SYN_COOKIES
1520 if (!th->rst && !th->syn && th->ack)
1521 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1522 #endif
1523 return sk;
1524 }
1525
1526 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1527 {
1528 const struct iphdr *iph = ip_hdr(skb);
1529
1530 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1531 if (!tcp_v4_check(skb->len, iph->saddr,
1532 iph->daddr, skb->csum)) {
1533 skb->ip_summed = CHECKSUM_UNNECESSARY;
1534 return 0;
1535 }
1536 }
1537
1538 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1539 skb->len, IPPROTO_TCP, 0);
1540
1541 if (skb->len <= 76) {
1542 return __skb_checksum_complete(skb);
1543 }
1544 return 0;
1545 }
1546
1547
1548 /* The socket must have it's spinlock held when we get
1549 * here.
1550 *
1551 * We have a potential double-lock case here, so even when
1552 * doing backlog processing we use the BH locking scheme.
1553 * This is because we cannot sleep with the original spinlock
1554 * held.
1555 */
1556 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1557 {
1558 struct sock *rsk;
1559 #ifdef CONFIG_TCP_MD5SIG
1560 /*
1561 * We really want to reject the packet as early as possible
1562 * if:
1563 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1564 * o There is an MD5 option and we're not expecting one
1565 */
1566 if (tcp_v4_inbound_md5_hash(sk, skb))
1567 goto discard;
1568 #endif
1569
1570 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1571 TCP_CHECK_TIMER(sk);
1572 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1573 rsk = sk;
1574 goto reset;
1575 }
1576 TCP_CHECK_TIMER(sk);
1577 return 0;
1578 }
1579
1580 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1581 goto csum_err;
1582
1583 if (sk->sk_state == TCP_LISTEN) {
1584 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1585 if (!nsk)
1586 goto discard;
1587
1588 if (nsk != sk) {
1589 if (tcp_child_process(sk, nsk, skb)) {
1590 rsk = nsk;
1591 goto reset;
1592 }
1593 return 0;
1594 }
1595 }
1596
1597 TCP_CHECK_TIMER(sk);
1598 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1599 rsk = sk;
1600 goto reset;
1601 }
1602 TCP_CHECK_TIMER(sk);
1603 return 0;
1604
1605 reset:
1606 tcp_v4_send_reset(rsk, skb);
1607 discard:
1608 kfree_skb(skb);
1609 /* Be careful here. If this function gets more complicated and
1610 * gcc suffers from register pressure on the x86, sk (in %ebx)
1611 * might be destroyed here. This current version compiles correctly,
1612 * but you have been warned.
1613 */
1614 return 0;
1615
1616 csum_err:
1617 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1618 goto discard;
1619 }
1620
1621 /*
1622 * From tcp_input.c
1623 */
1624
1625 int tcp_v4_rcv(struct sk_buff *skb)
1626 {
1627 const struct iphdr *iph;
1628 struct tcphdr *th;
1629 struct sock *sk;
1630 int ret;
1631
1632 if (skb->pkt_type != PACKET_HOST)
1633 goto discard_it;
1634
1635 /* Count it even if it's bad */
1636 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1637
1638 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1639 goto discard_it;
1640
1641 th = tcp_hdr(skb);
1642
1643 if (th->doff < sizeof(struct tcphdr) / 4)
1644 goto bad_packet;
1645 if (!pskb_may_pull(skb, th->doff * 4))
1646 goto discard_it;
1647
1648 /* An explanation is required here, I think.
1649 * Packet length and doff are validated by header prediction,
1650 * provided case of th->doff==0 is eliminated.
1651 * So, we defer the checks. */
1652 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1653 goto bad_packet;
1654
1655 th = tcp_hdr(skb);
1656 iph = ip_hdr(skb);
1657 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1658 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1659 skb->len - th->doff * 4);
1660 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1661 TCP_SKB_CB(skb)->when = 0;
1662 TCP_SKB_CB(skb)->flags = iph->tos;
1663 TCP_SKB_CB(skb)->sacked = 0;
1664
1665 sk = __inet_lookup(&tcp_hashinfo, iph->saddr, th->source,
1666 iph->daddr, th->dest, inet_iif(skb));
1667 if (!sk)
1668 goto no_tcp_socket;
1669
1670 process:
1671 if (sk->sk_state == TCP_TIME_WAIT)
1672 goto do_time_wait;
1673
1674 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1675 goto discard_and_relse;
1676 nf_reset(skb);
1677
1678 if (sk_filter(sk, skb))
1679 goto discard_and_relse;
1680
1681 skb->dev = NULL;
1682
1683 bh_lock_sock_nested(sk);
1684 ret = 0;
1685 if (!sock_owned_by_user(sk)) {
1686 #ifdef CONFIG_NET_DMA
1687 struct tcp_sock *tp = tcp_sk(sk);
1688 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1689 tp->ucopy.dma_chan = get_softnet_dma();
1690 if (tp->ucopy.dma_chan)
1691 ret = tcp_v4_do_rcv(sk, skb);
1692 else
1693 #endif
1694 {
1695 if (!tcp_prequeue(sk, skb))
1696 ret = tcp_v4_do_rcv(sk, skb);
1697 }
1698 } else
1699 sk_add_backlog(sk, skb);
1700 bh_unlock_sock(sk);
1701
1702 sock_put(sk);
1703
1704 return ret;
1705
1706 no_tcp_socket:
1707 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1708 goto discard_it;
1709
1710 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1711 bad_packet:
1712 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1713 } else {
1714 tcp_v4_send_reset(NULL, skb);
1715 }
1716
1717 discard_it:
1718 /* Discard frame. */
1719 kfree_skb(skb);
1720 return 0;
1721
1722 discard_and_relse:
1723 sock_put(sk);
1724 goto discard_it;
1725
1726 do_time_wait:
1727 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1728 inet_twsk_put(inet_twsk(sk));
1729 goto discard_it;
1730 }
1731
1732 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1733 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1734 inet_twsk_put(inet_twsk(sk));
1735 goto discard_it;
1736 }
1737 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1738 case TCP_TW_SYN: {
1739 struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
1740 iph->daddr, th->dest,
1741 inet_iif(skb));
1742 if (sk2) {
1743 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1744 inet_twsk_put(inet_twsk(sk));
1745 sk = sk2;
1746 goto process;
1747 }
1748 /* Fall through to ACK */
1749 }
1750 case TCP_TW_ACK:
1751 tcp_v4_timewait_ack(sk, skb);
1752 break;
1753 case TCP_TW_RST:
1754 goto no_tcp_socket;
1755 case TCP_TW_SUCCESS:;
1756 }
1757 goto discard_it;
1758 }
1759
1760 /* VJ's idea. Save last timestamp seen from this destination
1761 * and hold it at least for normal timewait interval to use for duplicate
1762 * segment detection in subsequent connections, before they enter synchronized
1763 * state.
1764 */
1765
1766 int tcp_v4_remember_stamp(struct sock *sk)
1767 {
1768 struct inet_sock *inet = inet_sk(sk);
1769 struct tcp_sock *tp = tcp_sk(sk);
1770 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1771 struct inet_peer *peer = NULL;
1772 int release_it = 0;
1773
1774 if (!rt || rt->rt_dst != inet->daddr) {
1775 peer = inet_getpeer(inet->daddr, 1);
1776 release_it = 1;
1777 } else {
1778 if (!rt->peer)
1779 rt_bind_peer(rt, 1);
1780 peer = rt->peer;
1781 }
1782
1783 if (peer) {
1784 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1785 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1786 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1787 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1788 peer->tcp_ts = tp->rx_opt.ts_recent;
1789 }
1790 if (release_it)
1791 inet_putpeer(peer);
1792 return 1;
1793 }
1794
1795 return 0;
1796 }
1797
1798 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1799 {
1800 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1801
1802 if (peer) {
1803 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1804
1805 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1806 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1807 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1808 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1809 peer->tcp_ts = tcptw->tw_ts_recent;
1810 }
1811 inet_putpeer(peer);
1812 return 1;
1813 }
1814
1815 return 0;
1816 }
1817
1818 struct inet_connection_sock_af_ops ipv4_specific = {
1819 .queue_xmit = ip_queue_xmit,
1820 .send_check = tcp_v4_send_check,
1821 .rebuild_header = inet_sk_rebuild_header,
1822 .conn_request = tcp_v4_conn_request,
1823 .syn_recv_sock = tcp_v4_syn_recv_sock,
1824 .remember_stamp = tcp_v4_remember_stamp,
1825 .net_header_len = sizeof(struct iphdr),
1826 .setsockopt = ip_setsockopt,
1827 .getsockopt = ip_getsockopt,
1828 .addr2sockaddr = inet_csk_addr2sockaddr,
1829 .sockaddr_len = sizeof(struct sockaddr_in),
1830 #ifdef CONFIG_COMPAT
1831 .compat_setsockopt = compat_ip_setsockopt,
1832 .compat_getsockopt = compat_ip_getsockopt,
1833 #endif
1834 };
1835
1836 #ifdef CONFIG_TCP_MD5SIG
1837 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1838 .md5_lookup = tcp_v4_md5_lookup,
1839 .calc_md5_hash = tcp_v4_calc_md5_hash,
1840 .md5_add = tcp_v4_md5_add_func,
1841 .md5_parse = tcp_v4_parse_md5_keys,
1842 };
1843 #endif
1844
1845 /* NOTE: A lot of things set to zero explicitly by call to
1846 * sk_alloc() so need not be done here.
1847 */
1848 static int tcp_v4_init_sock(struct sock *sk)
1849 {
1850 struct inet_connection_sock *icsk = inet_csk(sk);
1851 struct tcp_sock *tp = tcp_sk(sk);
1852
1853 skb_queue_head_init(&tp->out_of_order_queue);
1854 tcp_init_xmit_timers(sk);
1855 tcp_prequeue_init(tp);
1856
1857 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1858 tp->mdev = TCP_TIMEOUT_INIT;
1859
1860 /* So many TCP implementations out there (incorrectly) count the
1861 * initial SYN frame in their delayed-ACK and congestion control
1862 * algorithms that we must have the following bandaid to talk
1863 * efficiently to them. -DaveM
1864 */
1865 tp->snd_cwnd = 2;
1866
1867 /* See draft-stevens-tcpca-spec-01 for discussion of the
1868 * initialization of these values.
1869 */
1870 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1871 tp->snd_cwnd_clamp = ~0;
1872 tp->mss_cache = 536;
1873
1874 tp->reordering = sysctl_tcp_reordering;
1875 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1876
1877 sk->sk_state = TCP_CLOSE;
1878
1879 sk->sk_write_space = sk_stream_write_space;
1880 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1881
1882 icsk->icsk_af_ops = &ipv4_specific;
1883 icsk->icsk_sync_mss = tcp_sync_mss;
1884 #ifdef CONFIG_TCP_MD5SIG
1885 tp->af_specific = &tcp_sock_ipv4_specific;
1886 #endif
1887
1888 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1889 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1890
1891 atomic_inc(&tcp_sockets_allocated);
1892
1893 return 0;
1894 }
1895
1896 int tcp_v4_destroy_sock(struct sock *sk)
1897 {
1898 struct tcp_sock *tp = tcp_sk(sk);
1899
1900 tcp_clear_xmit_timers(sk);
1901
1902 tcp_cleanup_congestion_control(sk);
1903
1904 /* Cleanup up the write buffer. */
1905 tcp_write_queue_purge(sk);
1906
1907 /* Cleans up our, hopefully empty, out_of_order_queue. */
1908 __skb_queue_purge(&tp->out_of_order_queue);
1909
1910 #ifdef CONFIG_TCP_MD5SIG
1911 /* Clean up the MD5 key list, if any */
1912 if (tp->md5sig_info) {
1913 tcp_v4_clear_md5_list(sk);
1914 kfree(tp->md5sig_info);
1915 tp->md5sig_info = NULL;
1916 }
1917 #endif
1918
1919 #ifdef CONFIG_NET_DMA
1920 /* Cleans up our sk_async_wait_queue */
1921 __skb_queue_purge(&sk->sk_async_wait_queue);
1922 #endif
1923
1924 /* Clean prequeue, it must be empty really */
1925 __skb_queue_purge(&tp->ucopy.prequeue);
1926
1927 /* Clean up a referenced TCP bind bucket. */
1928 if (inet_csk(sk)->icsk_bind_hash)
1929 inet_put_port(&tcp_hashinfo, sk);
1930
1931 /*
1932 * If sendmsg cached page exists, toss it.
1933 */
1934 if (sk->sk_sndmsg_page) {
1935 __free_page(sk->sk_sndmsg_page);
1936 sk->sk_sndmsg_page = NULL;
1937 }
1938
1939 atomic_dec(&tcp_sockets_allocated);
1940
1941 return 0;
1942 }
1943
1944 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1945
1946 #ifdef CONFIG_PROC_FS
1947 /* Proc filesystem TCP sock list dumping. */
1948
1949 static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1950 {
1951 return hlist_empty(head) ? NULL :
1952 list_entry(head->first, struct inet_timewait_sock, tw_node);
1953 }
1954
1955 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1956 {
1957 return tw->tw_node.next ?
1958 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1959 }
1960
1961 static void *listening_get_next(struct seq_file *seq, void *cur)
1962 {
1963 struct inet_connection_sock *icsk;
1964 struct hlist_node *node;
1965 struct sock *sk = cur;
1966 struct tcp_iter_state* st = seq->private;
1967
1968 if (!sk) {
1969 st->bucket = 0;
1970 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1971 goto get_sk;
1972 }
1973
1974 ++st->num;
1975
1976 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1977 struct request_sock *req = cur;
1978
1979 icsk = inet_csk(st->syn_wait_sk);
1980 req = req->dl_next;
1981 while (1) {
1982 while (req) {
1983 if (req->rsk_ops->family == st->family) {
1984 cur = req;
1985 goto out;
1986 }
1987 req = req->dl_next;
1988 }
1989 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1990 break;
1991 get_req:
1992 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1993 }
1994 sk = sk_next(st->syn_wait_sk);
1995 st->state = TCP_SEQ_STATE_LISTENING;
1996 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1997 } else {
1998 icsk = inet_csk(sk);
1999 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2000 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2001 goto start_req;
2002 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2003 sk = sk_next(sk);
2004 }
2005 get_sk:
2006 sk_for_each_from(sk, node) {
2007 if (sk->sk_family == st->family) {
2008 cur = sk;
2009 goto out;
2010 }
2011 icsk = inet_csk(sk);
2012 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2013 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2014 start_req:
2015 st->uid = sock_i_uid(sk);
2016 st->syn_wait_sk = sk;
2017 st->state = TCP_SEQ_STATE_OPENREQ;
2018 st->sbucket = 0;
2019 goto get_req;
2020 }
2021 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2022 }
2023 if (++st->bucket < INET_LHTABLE_SIZE) {
2024 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
2025 goto get_sk;
2026 }
2027 cur = NULL;
2028 out:
2029 return cur;
2030 }
2031
2032 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2033 {
2034 void *rc = listening_get_next(seq, NULL);
2035
2036 while (rc && *pos) {
2037 rc = listening_get_next(seq, rc);
2038 --*pos;
2039 }
2040 return rc;
2041 }
2042
2043 static void *established_get_first(struct seq_file *seq)
2044 {
2045 struct tcp_iter_state* st = seq->private;
2046 void *rc = NULL;
2047
2048 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2049 struct sock *sk;
2050 struct hlist_node *node;
2051 struct inet_timewait_sock *tw;
2052
2053 read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2054 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2055 if (sk->sk_family != st->family) {
2056 continue;
2057 }
2058 rc = sk;
2059 goto out;
2060 }
2061 st->state = TCP_SEQ_STATE_TIME_WAIT;
2062 inet_twsk_for_each(tw, node,
2063 &tcp_hashinfo.ehash[st->bucket].twchain) {
2064 if (tw->tw_family != st->family) {
2065 continue;
2066 }
2067 rc = tw;
2068 goto out;
2069 }
2070 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2071 st->state = TCP_SEQ_STATE_ESTABLISHED;
2072 }
2073 out:
2074 return rc;
2075 }
2076
2077 static void *established_get_next(struct seq_file *seq, void *cur)
2078 {
2079 struct sock *sk = cur;
2080 struct inet_timewait_sock *tw;
2081 struct hlist_node *node;
2082 struct tcp_iter_state* st = seq->private;
2083
2084 ++st->num;
2085
2086 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2087 tw = cur;
2088 tw = tw_next(tw);
2089 get_tw:
2090 while (tw && tw->tw_family != st->family) {
2091 tw = tw_next(tw);
2092 }
2093 if (tw) {
2094 cur = tw;
2095 goto out;
2096 }
2097 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2098 st->state = TCP_SEQ_STATE_ESTABLISHED;
2099
2100 if (++st->bucket < tcp_hashinfo.ehash_size) {
2101 read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2102 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
2103 } else {
2104 cur = NULL;
2105 goto out;
2106 }
2107 } else
2108 sk = sk_next(sk);
2109
2110 sk_for_each_from(sk, node) {
2111 if (sk->sk_family == st->family)
2112 goto found;
2113 }
2114
2115 st->state = TCP_SEQ_STATE_TIME_WAIT;
2116 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2117 goto get_tw;
2118 found:
2119 cur = sk;
2120 out:
2121 return cur;
2122 }
2123
2124 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2125 {
2126 void *rc = established_get_first(seq);
2127
2128 while (rc && pos) {
2129 rc = established_get_next(seq, rc);
2130 --pos;
2131 }
2132 return rc;
2133 }
2134
2135 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2136 {
2137 void *rc;
2138 struct tcp_iter_state* st = seq->private;
2139
2140 inet_listen_lock(&tcp_hashinfo);
2141 st->state = TCP_SEQ_STATE_LISTENING;
2142 rc = listening_get_idx(seq, &pos);
2143
2144 if (!rc) {
2145 inet_listen_unlock(&tcp_hashinfo);
2146 st->state = TCP_SEQ_STATE_ESTABLISHED;
2147 rc = established_get_idx(seq, pos);
2148 }
2149
2150 return rc;
2151 }
2152
2153 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2154 {
2155 struct tcp_iter_state* st = seq->private;
2156 st->state = TCP_SEQ_STATE_LISTENING;
2157 st->num = 0;
2158 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2159 }
2160
2161 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2162 {
2163 void *rc = NULL;
2164 struct tcp_iter_state* st;
2165
2166 if (v == SEQ_START_TOKEN) {
2167 rc = tcp_get_idx(seq, 0);
2168 goto out;
2169 }
2170 st = seq->private;
2171
2172 switch (st->state) {
2173 case TCP_SEQ_STATE_OPENREQ:
2174 case TCP_SEQ_STATE_LISTENING:
2175 rc = listening_get_next(seq, v);
2176 if (!rc) {
2177 inet_listen_unlock(&tcp_hashinfo);
2178 st->state = TCP_SEQ_STATE_ESTABLISHED;
2179 rc = established_get_first(seq);
2180 }
2181 break;
2182 case TCP_SEQ_STATE_ESTABLISHED:
2183 case TCP_SEQ_STATE_TIME_WAIT:
2184 rc = established_get_next(seq, v);
2185 break;
2186 }
2187 out:
2188 ++*pos;
2189 return rc;
2190 }
2191
2192 static void tcp_seq_stop(struct seq_file *seq, void *v)
2193 {
2194 struct tcp_iter_state* st = seq->private;
2195
2196 switch (st->state) {
2197 case TCP_SEQ_STATE_OPENREQ:
2198 if (v) {
2199 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2200 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2201 }
2202 case TCP_SEQ_STATE_LISTENING:
2203 if (v != SEQ_START_TOKEN)
2204 inet_listen_unlock(&tcp_hashinfo);
2205 break;
2206 case TCP_SEQ_STATE_TIME_WAIT:
2207 case TCP_SEQ_STATE_ESTABLISHED:
2208 if (v)
2209 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2210 break;
2211 }
2212 }
2213
2214 static int tcp_seq_open(struct inode *inode, struct file *file)
2215 {
2216 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2217 struct seq_file *seq;
2218 struct tcp_iter_state *s;
2219 int rc;
2220
2221 if (unlikely(afinfo == NULL))
2222 return -EINVAL;
2223
2224 s = kzalloc(sizeof(*s), GFP_KERNEL);
2225 if (!s)
2226 return -ENOMEM;
2227 s->family = afinfo->family;
2228 s->seq_ops.start = tcp_seq_start;
2229 s->seq_ops.next = tcp_seq_next;
2230 s->seq_ops.show = afinfo->seq_show;
2231 s->seq_ops.stop = tcp_seq_stop;
2232
2233 rc = seq_open(file, &s->seq_ops);
2234 if (rc)
2235 goto out_kfree;
2236 seq = file->private_data;
2237 seq->private = s;
2238 out:
2239 return rc;
2240 out_kfree:
2241 kfree(s);
2242 goto out;
2243 }
2244
2245 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
2246 {
2247 int rc = 0;
2248 struct proc_dir_entry *p;
2249
2250 if (!afinfo)
2251 return -EINVAL;
2252 afinfo->seq_fops->owner = afinfo->owner;
2253 afinfo->seq_fops->open = tcp_seq_open;
2254 afinfo->seq_fops->read = seq_read;
2255 afinfo->seq_fops->llseek = seq_lseek;
2256 afinfo->seq_fops->release = seq_release_private;
2257
2258 p = proc_net_fops_create(&init_net, afinfo->name, S_IRUGO, afinfo->seq_fops);
2259 if (p)
2260 p->data = afinfo;
2261 else
2262 rc = -ENOMEM;
2263 return rc;
2264 }
2265
2266 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
2267 {
2268 if (!afinfo)
2269 return;
2270 proc_net_remove(&init_net, afinfo->name);
2271 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
2272 }
2273
2274 static void get_openreq4(struct sock *sk, struct request_sock *req,
2275 char *tmpbuf, int i, int uid)
2276 {
2277 const struct inet_request_sock *ireq = inet_rsk(req);
2278 int ttd = req->expires - jiffies;
2279
2280 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2281 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
2282 i,
2283 ireq->loc_addr,
2284 ntohs(inet_sk(sk)->sport),
2285 ireq->rmt_addr,
2286 ntohs(ireq->rmt_port),
2287 TCP_SYN_RECV,
2288 0, 0, /* could print option size, but that is af dependent. */
2289 1, /* timers active (only the expire timer) */
2290 jiffies_to_clock_t(ttd),
2291 req->retrans,
2292 uid,
2293 0, /* non standard timer */
2294 0, /* open_requests have no inode */
2295 atomic_read(&sk->sk_refcnt),
2296 req);
2297 }
2298
2299 static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
2300 {
2301 int timer_active;
2302 unsigned long timer_expires;
2303 struct tcp_sock *tp = tcp_sk(sk);
2304 const struct inet_connection_sock *icsk = inet_csk(sk);
2305 struct inet_sock *inet = inet_sk(sk);
2306 __be32 dest = inet->daddr;
2307 __be32 src = inet->rcv_saddr;
2308 __u16 destp = ntohs(inet->dport);
2309 __u16 srcp = ntohs(inet->sport);
2310
2311 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2312 timer_active = 1;
2313 timer_expires = icsk->icsk_timeout;
2314 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2315 timer_active = 4;
2316 timer_expires = icsk->icsk_timeout;
2317 } else if (timer_pending(&sk->sk_timer)) {
2318 timer_active = 2;
2319 timer_expires = sk->sk_timer.expires;
2320 } else {
2321 timer_active = 0;
2322 timer_expires = jiffies;
2323 }
2324
2325 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2326 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
2327 i, src, srcp, dest, destp, sk->sk_state,
2328 tp->write_seq - tp->snd_una,
2329 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2330 (tp->rcv_nxt - tp->copied_seq),
2331 timer_active,
2332 jiffies_to_clock_t(timer_expires - jiffies),
2333 icsk->icsk_retransmits,
2334 sock_i_uid(sk),
2335 icsk->icsk_probes_out,
2336 sock_i_ino(sk),
2337 atomic_read(&sk->sk_refcnt), sk,
2338 icsk->icsk_rto,
2339 icsk->icsk_ack.ato,
2340 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2341 tp->snd_cwnd,
2342 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
2343 }
2344
2345 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2346 char *tmpbuf, int i)
2347 {
2348 __be32 dest, src;
2349 __u16 destp, srcp;
2350 int ttd = tw->tw_ttd - jiffies;
2351
2352 if (ttd < 0)
2353 ttd = 0;
2354
2355 dest = tw->tw_daddr;
2356 src = tw->tw_rcv_saddr;
2357 destp = ntohs(tw->tw_dport);
2358 srcp = ntohs(tw->tw_sport);
2359
2360 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2361 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
2362 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2363 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2364 atomic_read(&tw->tw_refcnt), tw);
2365 }
2366
2367 #define TMPSZ 150
2368
2369 static int tcp4_seq_show(struct seq_file *seq, void *v)
2370 {
2371 struct tcp_iter_state* st;
2372 char tmpbuf[TMPSZ + 1];
2373
2374 if (v == SEQ_START_TOKEN) {
2375 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2376 " sl local_address rem_address st tx_queue "
2377 "rx_queue tr tm->when retrnsmt uid timeout "
2378 "inode");
2379 goto out;
2380 }
2381 st = seq->private;
2382
2383 switch (st->state) {
2384 case TCP_SEQ_STATE_LISTENING:
2385 case TCP_SEQ_STATE_ESTABLISHED:
2386 get_tcp4_sock(v, tmpbuf, st->num);
2387 break;
2388 case TCP_SEQ_STATE_OPENREQ:
2389 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
2390 break;
2391 case TCP_SEQ_STATE_TIME_WAIT:
2392 get_timewait4_sock(v, tmpbuf, st->num);
2393 break;
2394 }
2395 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
2396 out:
2397 return 0;
2398 }
2399
2400 static struct file_operations tcp4_seq_fops;
2401 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2402 .owner = THIS_MODULE,
2403 .name = "tcp",
2404 .family = AF_INET,
2405 .seq_show = tcp4_seq_show,
2406 .seq_fops = &tcp4_seq_fops,
2407 };
2408
2409 int __init tcp4_proc_init(void)
2410 {
2411 return tcp_proc_register(&tcp4_seq_afinfo);
2412 }
2413
2414 void tcp4_proc_exit(void)
2415 {
2416 tcp_proc_unregister(&tcp4_seq_afinfo);
2417 }
2418 #endif /* CONFIG_PROC_FS */
2419
2420 DEFINE_PROTO_INUSE(tcp)
2421
2422 struct proto tcp_prot = {
2423 .name = "TCP",
2424 .owner = THIS_MODULE,
2425 .close = tcp_close,
2426 .connect = tcp_v4_connect,
2427 .disconnect = tcp_disconnect,
2428 .accept = inet_csk_accept,
2429 .ioctl = tcp_ioctl,
2430 .init = tcp_v4_init_sock,
2431 .destroy = tcp_v4_destroy_sock,
2432 .shutdown = tcp_shutdown,
2433 .setsockopt = tcp_setsockopt,
2434 .getsockopt = tcp_getsockopt,
2435 .recvmsg = tcp_recvmsg,
2436 .backlog_rcv = tcp_v4_do_rcv,
2437 .hash = tcp_v4_hash,
2438 .unhash = tcp_unhash,
2439 .get_port = tcp_v4_get_port,
2440 .enter_memory_pressure = tcp_enter_memory_pressure,
2441 .sockets_allocated = &tcp_sockets_allocated,
2442 .orphan_count = &tcp_orphan_count,
2443 .memory_allocated = &tcp_memory_allocated,
2444 .memory_pressure = &tcp_memory_pressure,
2445 .sysctl_mem = sysctl_tcp_mem,
2446 .sysctl_wmem = sysctl_tcp_wmem,
2447 .sysctl_rmem = sysctl_tcp_rmem,
2448 .max_header = MAX_TCP_HEADER,
2449 .obj_size = sizeof(struct tcp_sock),
2450 .twsk_prot = &tcp_timewait_sock_ops,
2451 .rsk_prot = &tcp_request_sock_ops,
2452 #ifdef CONFIG_COMPAT
2453 .compat_setsockopt = compat_tcp_setsockopt,
2454 .compat_getsockopt = compat_tcp_getsockopt,
2455 #endif
2456 REF_PROTO_INUSE(tcp)
2457 };
2458
2459 void __init tcp_v4_init(struct net_proto_family *ops)
2460 {
2461 if (inet_csk_ctl_sock_create(&tcp_socket, PF_INET, SOCK_RAW,
2462 IPPROTO_TCP) < 0)
2463 panic("Failed to create the TCP control socket.\n");
2464 }
2465
2466 EXPORT_SYMBOL(ipv4_specific);
2467 EXPORT_SYMBOL(tcp_hashinfo);
2468 EXPORT_SYMBOL(tcp_prot);
2469 EXPORT_SYMBOL(tcp_unhash);
2470 EXPORT_SYMBOL(tcp_v4_conn_request);
2471 EXPORT_SYMBOL(tcp_v4_connect);
2472 EXPORT_SYMBOL(tcp_v4_do_rcv);
2473 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2474 EXPORT_SYMBOL(tcp_v4_send_check);
2475 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2476
2477 #ifdef CONFIG_PROC_FS
2478 EXPORT_SYMBOL(tcp_proc_register);
2479 EXPORT_SYMBOL(tcp_proc_unregister);
2480 #endif
2481 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2482
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