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[TCP]: Fix MD5 signature handling on big-endian.
[linux-2.6/kmemtrace.git] / net / ipv4 / tcp_ipv4.c
blobe089a978e128057e8b7bc245beaa3aad81be12a0
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/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 /* Check TCP sequence numbers in ICMP packets. */
88 #define ICMP_MIN_LENGTH 8
89
90 /* Socket used for sending RSTs */
91 static struct socket *tcp_socket __read_mostly;
92
93 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
94
95 #ifdef CONFIG_TCP_MD5SIG
96 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
97 __be32 addr);
98 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
99 __be32 saddr, __be32 daddr,
100 struct tcphdr *th, int protocol,
101 int tcplen);
102 #endif
103
104 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
105 .lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
106 .lhash_users = ATOMIC_INIT(0),
107 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
108 };
109
110 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
111 {
112 return inet_csk_get_port(&tcp_hashinfo, sk, snum,
113 inet_csk_bind_conflict);
114 }
115
116 static void tcp_v4_hash(struct sock *sk)
117 {
118 inet_hash(&tcp_hashinfo, sk);
119 }
120
121 void tcp_unhash(struct sock *sk)
122 {
123 inet_unhash(&tcp_hashinfo, sk);
124 }
125
126 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
127 {
128 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
129 ip_hdr(skb)->saddr,
130 tcp_hdr(skb)->dest,
131 tcp_hdr(skb)->source);
132 }
133
134 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
135 {
136 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
137 struct tcp_sock *tp = tcp_sk(sk);
138
139 /* With PAWS, it is safe from the viewpoint
140 of data integrity. Even without PAWS it is safe provided sequence
141 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
142
143 Actually, the idea is close to VJ's one, only timestamp cache is
144 held not per host, but per port pair and TW bucket is used as state
145 holder.
146
147 If TW bucket has been already destroyed we fall back to VJ's scheme
148 and use initial timestamp retrieved from peer table.
149 */
150 if (tcptw->tw_ts_recent_stamp &&
151 (twp == NULL || (sysctl_tcp_tw_reuse &&
152 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
153 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
154 if (tp->write_seq == 0)
155 tp->write_seq = 1;
156 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
157 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
158 sock_hold(sktw);
159 return 1;
160 }
161
162 return 0;
163 }
164
165 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
166
167 /* This will initiate an outgoing connection. */
168 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
169 {
170 struct inet_sock *inet = inet_sk(sk);
171 struct tcp_sock *tp = tcp_sk(sk);
172 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
173 struct rtable *rt;
174 __be32 daddr, nexthop;
175 int tmp;
176 int err;
177
178 if (addr_len < sizeof(struct sockaddr_in))
179 return -EINVAL;
180
181 if (usin->sin_family != AF_INET)
182 return -EAFNOSUPPORT;
183
184 nexthop = daddr = usin->sin_addr.s_addr;
185 if (inet->opt && inet->opt->srr) {
186 if (!daddr)
187 return -EINVAL;
188 nexthop = inet->opt->faddr;
189 }
190
191 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
192 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
193 IPPROTO_TCP,
194 inet->sport, usin->sin_port, sk, 1);
195 if (tmp < 0) {
196 if (tmp == -ENETUNREACH)
197 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
198 return tmp;
199 }
200
201 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
202 ip_rt_put(rt);
203 return -ENETUNREACH;
204 }
205
206 if (!inet->opt || !inet->opt->srr)
207 daddr = rt->rt_dst;
208
209 if (!inet->saddr)
210 inet->saddr = rt->rt_src;
211 inet->rcv_saddr = inet->saddr;
212
213 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
214 /* Reset inherited state */
215 tp->rx_opt.ts_recent = 0;
216 tp->rx_opt.ts_recent_stamp = 0;
217 tp->write_seq = 0;
218 }
219
220 if (tcp_death_row.sysctl_tw_recycle &&
221 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
222 struct inet_peer *peer = rt_get_peer(rt);
223 /*
224 * VJ's idea. We save last timestamp seen from
225 * the destination in peer table, when entering state
226 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
227 * when trying new connection.
228 */
229 if (peer != NULL &&
230 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
231 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
232 tp->rx_opt.ts_recent = peer->tcp_ts;
233 }
234 }
235
236 inet->dport = usin->sin_port;
237 inet->daddr = daddr;
238
239 inet_csk(sk)->icsk_ext_hdr_len = 0;
240 if (inet->opt)
241 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
242
243 tp->rx_opt.mss_clamp = 536;
244
245 /* Socket identity is still unknown (sport may be zero).
246 * However we set state to SYN-SENT and not releasing socket
247 * lock select source port, enter ourselves into the hash tables and
248 * complete initialization after this.
249 */
250 tcp_set_state(sk, TCP_SYN_SENT);
251 err = inet_hash_connect(&tcp_death_row, sk);
252 if (err)
253 goto failure;
254
255 err = ip_route_newports(&rt, IPPROTO_TCP,
256 inet->sport, inet->dport, sk);
257 if (err)
258 goto failure;
259
260 /* OK, now commit destination to socket. */
261 sk->sk_gso_type = SKB_GSO_TCPV4;
262 sk_setup_caps(sk, &rt->u.dst);
263
264 if (!tp->write_seq)
265 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
266 inet->daddr,
267 inet->sport,
268 usin->sin_port);
269
270 inet->id = tp->write_seq ^ jiffies;
271
272 err = tcp_connect(sk);
273 rt = NULL;
274 if (err)
275 goto failure;
276
277 return 0;
278
279 failure:
280 /*
281 * This unhashes the socket and releases the local port,
282 * if necessary.
283 */
284 tcp_set_state(sk, TCP_CLOSE);
285 ip_rt_put(rt);
286 sk->sk_route_caps = 0;
287 inet->dport = 0;
288 return err;
289 }
290
291 /*
292 * This routine does path mtu discovery as defined in RFC1191.
293 */
294 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
295 {
296 struct dst_entry *dst;
297 struct inet_sock *inet = inet_sk(sk);
298
299 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
300 * send out by Linux are always <576bytes so they should go through
301 * unfragmented).
302 */
303 if (sk->sk_state == TCP_LISTEN)
304 return;
305
306 /* We don't check in the destentry if pmtu discovery is forbidden
307 * on this route. We just assume that no packet_to_big packets
308 * are send back when pmtu discovery is not active.
309 * There is a small race when the user changes this flag in the
310 * route, but I think that's acceptable.
311 */
312 if ((dst = __sk_dst_check(sk, 0)) == NULL)
313 return;
314
315 dst->ops->update_pmtu(dst, mtu);
316
317 /* Something is about to be wrong... Remember soft error
318 * for the case, if this connection will not able to recover.
319 */
320 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
321 sk->sk_err_soft = EMSGSIZE;
322
323 mtu = dst_mtu(dst);
324
325 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
326 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
327 tcp_sync_mss(sk, mtu);
328
329 /* Resend the TCP packet because it's
330 * clear that the old packet has been
331 * dropped. This is the new "fast" path mtu
332 * discovery.
333 */
334 tcp_simple_retransmit(sk);
335 } /* else let the usual retransmit timer handle it */
336 }
337
338 /*
339 * This routine is called by the ICMP module when it gets some
340 * sort of error condition. If err < 0 then the socket should
341 * be closed and the error returned to the user. If err > 0
342 * it's just the icmp type << 8 | icmp code. After adjustment
343 * header points to the first 8 bytes of the tcp header. We need
344 * to find the appropriate port.
345 *
346 * The locking strategy used here is very "optimistic". When
347 * someone else accesses the socket the ICMP is just dropped
348 * and for some paths there is no check at all.
349 * A more general error queue to queue errors for later handling
350 * is probably better.
351 *
352 */
353
354 void tcp_v4_err(struct sk_buff *skb, u32 info)
355 {
356 struct iphdr *iph = (struct iphdr *)skb->data;
357 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
358 struct tcp_sock *tp;
359 struct inet_sock *inet;
360 const int type = icmp_hdr(skb)->type;
361 const int code = icmp_hdr(skb)->code;
362 struct sock *sk;
363 __u32 seq;
364 int err;
365
366 if (skb->len < (iph->ihl << 2) + 8) {
367 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
368 return;
369 }
370
371 sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr,
372 th->source, inet_iif(skb));
373 if (!sk) {
374 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
375 return;
376 }
377 if (sk->sk_state == TCP_TIME_WAIT) {
378 inet_twsk_put(inet_twsk(sk));
379 return;
380 }
381
382 bh_lock_sock(sk);
383 /* If too many ICMPs get dropped on busy
384 * servers this needs to be solved differently.
385 */
386 if (sock_owned_by_user(sk))
387 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
388
389 if (sk->sk_state == TCP_CLOSE)
390 goto out;
391
392 tp = tcp_sk(sk);
393 seq = ntohl(th->seq);
394 if (sk->sk_state != TCP_LISTEN &&
395 !between(seq, tp->snd_una, tp->snd_nxt)) {
396 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
397 goto out;
398 }
399
400 switch (type) {
401 case ICMP_SOURCE_QUENCH:
402 /* Just silently ignore these. */
403 goto out;
404 case ICMP_PARAMETERPROB:
405 err = EPROTO;
406 break;
407 case ICMP_DEST_UNREACH:
408 if (code > NR_ICMP_UNREACH)
409 goto out;
410
411 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
412 if (!sock_owned_by_user(sk))
413 do_pmtu_discovery(sk, iph, info);
414 goto out;
415 }
416
417 err = icmp_err_convert[code].errno;
418 break;
419 case ICMP_TIME_EXCEEDED:
420 err = EHOSTUNREACH;
421 break;
422 default:
423 goto out;
424 }
425
426 switch (sk->sk_state) {
427 struct request_sock *req, **prev;
428 case TCP_LISTEN:
429 if (sock_owned_by_user(sk))
430 goto out;
431
432 req = inet_csk_search_req(sk, &prev, th->dest,
433 iph->daddr, iph->saddr);
434 if (!req)
435 goto out;
436
437 /* ICMPs are not backlogged, hence we cannot get
438 an established socket here.
439 */
440 BUG_TRAP(!req->sk);
441
442 if (seq != tcp_rsk(req)->snt_isn) {
443 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
444 goto out;
445 }
446
447 /*
448 * Still in SYN_RECV, just remove it silently.
449 * There is no good way to pass the error to the newly
450 * created socket, and POSIX does not want network
451 * errors returned from accept().
452 */
453 inet_csk_reqsk_queue_drop(sk, req, prev);
454 goto out;
455
456 case TCP_SYN_SENT:
457 case TCP_SYN_RECV: /* Cannot happen.
458 It can f.e. if SYNs crossed.
459 */
460 if (!sock_owned_by_user(sk)) {
461 sk->sk_err = err;
462
463 sk->sk_error_report(sk);
464
465 tcp_done(sk);
466 } else {
467 sk->sk_err_soft = err;
468 }
469 goto out;
470 }
471
472 /* If we've already connected we will keep trying
473 * until we time out, or the user gives up.
474 *
475 * rfc1122 4.2.3.9 allows to consider as hard errors
476 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
477 * but it is obsoleted by pmtu discovery).
478 *
479 * Note, that in modern internet, where routing is unreliable
480 * and in each dark corner broken firewalls sit, sending random
481 * errors ordered by their masters even this two messages finally lose
482 * their original sense (even Linux sends invalid PORT_UNREACHs)
483 *
484 * Now we are in compliance with RFCs.
485 * --ANK (980905)
486 */
487
488 inet = inet_sk(sk);
489 if (!sock_owned_by_user(sk) && inet->recverr) {
490 sk->sk_err = err;
491 sk->sk_error_report(sk);
492 } else { /* Only an error on timeout */
493 sk->sk_err_soft = err;
494 }
495
496 out:
497 bh_unlock_sock(sk);
498 sock_put(sk);
499 }
500
501 /* This routine computes an IPv4 TCP checksum. */
502 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
503 {
504 struct inet_sock *inet = inet_sk(sk);
505 struct tcphdr *th = tcp_hdr(skb);
506
507 if (skb->ip_summed == CHECKSUM_PARTIAL) {
508 th->check = ~tcp_v4_check(len, inet->saddr,
509 inet->daddr, 0);
510 skb->csum_start = skb_transport_header(skb) - skb->head;
511 skb->csum_offset = offsetof(struct tcphdr, check);
512 } else {
513 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
514 csum_partial((char *)th,
515 th->doff << 2,
516 skb->csum));
517 }
518 }
519
520 int tcp_v4_gso_send_check(struct sk_buff *skb)
521 {
522 const struct iphdr *iph;
523 struct tcphdr *th;
524
525 if (!pskb_may_pull(skb, sizeof(*th)))
526 return -EINVAL;
527
528 iph = ip_hdr(skb);
529 th = tcp_hdr(skb);
530
531 th->check = 0;
532 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
533 skb->csum_start = skb_transport_header(skb) - skb->head;
534 skb->csum_offset = offsetof(struct tcphdr, check);
535 skb->ip_summed = CHECKSUM_PARTIAL;
536 return 0;
537 }
538
539 /*
540 * This routine will send an RST to the other tcp.
541 *
542 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
543 * for reset.
544 * Answer: if a packet caused RST, it is not for a socket
545 * existing in our system, if it is matched to a socket,
546 * it is just duplicate segment or bug in other side's TCP.
547 * So that we build reply only basing on parameters
548 * arrived with segment.
549 * Exception: precedence violation. We do not implement it in any case.
550 */
551
552 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
553 {
554 struct tcphdr *th = tcp_hdr(skb);
555 struct {
556 struct tcphdr th;
557 #ifdef CONFIG_TCP_MD5SIG
558 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
559 #endif
560 } rep;
561 struct ip_reply_arg arg;
562 #ifdef CONFIG_TCP_MD5SIG
563 struct tcp_md5sig_key *key;
564 #endif
565
566 /* Never send a reset in response to a reset. */
567 if (th->rst)
568 return;
569
570 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
571 return;
572
573 /* Swap the send and the receive. */
574 memset(&rep, 0, sizeof(rep));
575 rep.th.dest = th->source;
576 rep.th.source = th->dest;
577 rep.th.doff = sizeof(struct tcphdr) / 4;
578 rep.th.rst = 1;
579
580 if (th->ack) {
581 rep.th.seq = th->ack_seq;
582 } else {
583 rep.th.ack = 1;
584 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
585 skb->len - (th->doff << 2));
586 }
587
588 memset(&arg, 0, sizeof(arg));
589 arg.iov[0].iov_base = (unsigned char *)&rep;
590 arg.iov[0].iov_len = sizeof(rep.th);
591
592 #ifdef CONFIG_TCP_MD5SIG
593 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
594 if (key) {
595 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
596 (TCPOPT_NOP << 16) |
597 (TCPOPT_MD5SIG << 8) |
598 TCPOLEN_MD5SIG);
599 /* Update length and the length the header thinks exists */
600 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
601 rep.th.doff = arg.iov[0].iov_len / 4;
602
603 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
604 key,
605 ip_hdr(skb)->daddr,
606 ip_hdr(skb)->saddr,
607 &rep.th, IPPROTO_TCP,
608 arg.iov[0].iov_len);
609 }
610 #endif
611 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
612 ip_hdr(skb)->saddr, /* XXX */
613 sizeof(struct tcphdr), IPPROTO_TCP, 0);
614 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
615
616 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
617
618 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
619 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
620 }
621
622 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
623 outside socket context is ugly, certainly. What can I do?
624 */
625
626 static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
627 struct sk_buff *skb, u32 seq, u32 ack,
628 u32 win, u32 ts)
629 {
630 struct tcphdr *th = tcp_hdr(skb);
631 struct {
632 struct tcphdr th;
633 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
634 #ifdef CONFIG_TCP_MD5SIG
635 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
636 #endif
637 ];
638 } rep;
639 struct ip_reply_arg arg;
640 #ifdef CONFIG_TCP_MD5SIG
641 struct tcp_md5sig_key *key;
642 struct tcp_md5sig_key tw_key;
643 #endif
644
645 memset(&rep.th, 0, sizeof(struct tcphdr));
646 memset(&arg, 0, sizeof(arg));
647
648 arg.iov[0].iov_base = (unsigned char *)&rep;
649 arg.iov[0].iov_len = sizeof(rep.th);
650 if (ts) {
651 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
652 (TCPOPT_TIMESTAMP << 8) |
653 TCPOLEN_TIMESTAMP);
654 rep.opt[1] = htonl(tcp_time_stamp);
655 rep.opt[2] = htonl(ts);
656 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
657 }
658
659 /* Swap the send and the receive. */
660 rep.th.dest = th->source;
661 rep.th.source = th->dest;
662 rep.th.doff = arg.iov[0].iov_len / 4;
663 rep.th.seq = htonl(seq);
664 rep.th.ack_seq = htonl(ack);
665 rep.th.ack = 1;
666 rep.th.window = htons(win);
667
668 #ifdef CONFIG_TCP_MD5SIG
669 /*
670 * The SKB holds an imcoming packet, but may not have a valid ->sk
671 * pointer. This is especially the case when we're dealing with a
672 * TIME_WAIT ack, because the sk structure is long gone, and only
673 * the tcp_timewait_sock remains. So the md5 key is stashed in that
674 * structure, and we use it in preference. I believe that (twsk ||
675 * skb->sk) holds true, but we program defensively.
676 */
677 if (!twsk && skb->sk) {
678 key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
679 } else if (twsk && twsk->tw_md5_keylen) {
680 tw_key.key = twsk->tw_md5_key;
681 tw_key.keylen = twsk->tw_md5_keylen;
682 key = &tw_key;
683 } else
684 key = NULL;
685
686 if (key) {
687 int offset = (ts) ? 3 : 0;
688
689 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
690 (TCPOPT_NOP << 16) |
691 (TCPOPT_MD5SIG << 8) |
692 TCPOLEN_MD5SIG);
693 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
694 rep.th.doff = arg.iov[0].iov_len/4;
695
696 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
697 key,
698 ip_hdr(skb)->daddr,
699 ip_hdr(skb)->saddr,
700 &rep.th, IPPROTO_TCP,
701 arg.iov[0].iov_len);
702 }
703 #endif
704 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
705 ip_hdr(skb)->saddr, /* XXX */
706 arg.iov[0].iov_len, IPPROTO_TCP, 0);
707 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
708 if (twsk)
709 arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
710
711 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
712
713 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
714 }
715
716 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
717 {
718 struct inet_timewait_sock *tw = inet_twsk(sk);
719 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
720
721 tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
722 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
723 tcptw->tw_ts_recent);
724
725 inet_twsk_put(tw);
726 }
727
728 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
729 struct request_sock *req)
730 {
731 tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
732 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
733 req->ts_recent);
734 }
735
736 /*
737 * Send a SYN-ACK after having received an ACK.
738 * This still operates on a request_sock only, not on a big
739 * socket.
740 */
741 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
742 struct dst_entry *dst)
743 {
744 const struct inet_request_sock *ireq = inet_rsk(req);
745 int err = -1;
746 struct sk_buff * skb;
747
748 /* First, grab a route. */
749 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
750 goto out;
751
752 skb = tcp_make_synack(sk, dst, req);
753
754 if (skb) {
755 struct tcphdr *th = tcp_hdr(skb);
756
757 th->check = tcp_v4_check(skb->len,
758 ireq->loc_addr,
759 ireq->rmt_addr,
760 csum_partial((char *)th, skb->len,
761 skb->csum));
762
763 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
764 ireq->rmt_addr,
765 ireq->opt);
766 err = net_xmit_eval(err);
767 }
768
769 out:
770 dst_release(dst);
771 return err;
772 }
773
774 /*
775 * IPv4 request_sock destructor.
776 */
777 static void tcp_v4_reqsk_destructor(struct request_sock *req)
778 {
779 kfree(inet_rsk(req)->opt);
780 }
781
782 #ifdef CONFIG_SYN_COOKIES
783 static void syn_flood_warning(struct sk_buff *skb)
784 {
785 static unsigned long warntime;
786
787 if (time_after(jiffies, (warntime + HZ * 60))) {
788 warntime = jiffies;
789 printk(KERN_INFO
790 "possible SYN flooding on port %d. Sending cookies.\n",
791 ntohs(tcp_hdr(skb)->dest));
792 }
793 }
794 #endif
795
796 /*
797 * Save and compile IPv4 options into the request_sock if needed.
798 */
799 static struct ip_options *tcp_v4_save_options(struct sock *sk,
800 struct sk_buff *skb)
801 {
802 struct ip_options *opt = &(IPCB(skb)->opt);
803 struct ip_options *dopt = NULL;
804
805 if (opt && opt->optlen) {
806 int opt_size = optlength(opt);
807 dopt = kmalloc(opt_size, GFP_ATOMIC);
808 if (dopt) {
809 if (ip_options_echo(dopt, skb)) {
810 kfree(dopt);
811 dopt = NULL;
812 }
813 }
814 }
815 return dopt;
816 }
817
818 #ifdef CONFIG_TCP_MD5SIG
819 /*
820 * RFC2385 MD5 checksumming requires a mapping of
821 * IP address->MD5 Key.
822 * We need to maintain these in the sk structure.
823 */
824
825 /* Find the Key structure for an address. */
826 static struct tcp_md5sig_key *
827 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
828 {
829 struct tcp_sock *tp = tcp_sk(sk);
830 int i;
831
832 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
833 return NULL;
834 for (i = 0; i < tp->md5sig_info->entries4; i++) {
835 if (tp->md5sig_info->keys4[i].addr == addr)
836 return &tp->md5sig_info->keys4[i].base;
837 }
838 return NULL;
839 }
840
841 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
842 struct sock *addr_sk)
843 {
844 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
845 }
846
847 EXPORT_SYMBOL(tcp_v4_md5_lookup);
848
849 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
850 struct request_sock *req)
851 {
852 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
853 }
854
855 /* This can be called on a newly created socket, from other files */
856 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
857 u8 *newkey, u8 newkeylen)
858 {
859 /* Add Key to the list */
860 struct tcp4_md5sig_key *key;
861 struct tcp_sock *tp = tcp_sk(sk);
862 struct tcp4_md5sig_key *keys;
863
864 key = (struct tcp4_md5sig_key *)tcp_v4_md5_do_lookup(sk, addr);
865 if (key) {
866 /* Pre-existing entry - just update that one. */
867 kfree(key->base.key);
868 key->base.key = newkey;
869 key->base.keylen = newkeylen;
870 } else {
871 struct tcp_md5sig_info *md5sig;
872
873 if (!tp->md5sig_info) {
874 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
875 GFP_ATOMIC);
876 if (!tp->md5sig_info) {
877 kfree(newkey);
878 return -ENOMEM;
879 }
880 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
881 }
882 if (tcp_alloc_md5sig_pool() == NULL) {
883 kfree(newkey);
884 return -ENOMEM;
885 }
886 md5sig = tp->md5sig_info;
887
888 if (md5sig->alloced4 == md5sig->entries4) {
889 keys = kmalloc((sizeof(*keys) *
890 (md5sig->entries4 + 1)), GFP_ATOMIC);
891 if (!keys) {
892 kfree(newkey);
893 tcp_free_md5sig_pool();
894 return -ENOMEM;
895 }
896
897 if (md5sig->entries4)
898 memcpy(keys, md5sig->keys4,
899 sizeof(*keys) * md5sig->entries4);
900
901 /* Free old key list, and reference new one */
902 if (md5sig->keys4)
903 kfree(md5sig->keys4);
904 md5sig->keys4 = keys;
905 md5sig->alloced4++;
906 }
907 md5sig->entries4++;
908 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
909 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
910 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
911 }
912 return 0;
913 }
914
915 EXPORT_SYMBOL(tcp_v4_md5_do_add);
916
917 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
918 u8 *newkey, u8 newkeylen)
919 {
920 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
921 newkey, newkeylen);
922 }
923
924 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
925 {
926 struct tcp_sock *tp = tcp_sk(sk);
927 int i;
928
929 for (i = 0; i < tp->md5sig_info->entries4; i++) {
930 if (tp->md5sig_info->keys4[i].addr == addr) {
931 /* Free the key */
932 kfree(tp->md5sig_info->keys4[i].base.key);
933 tp->md5sig_info->entries4--;
934
935 if (tp->md5sig_info->entries4 == 0) {
936 kfree(tp->md5sig_info->keys4);
937 tp->md5sig_info->keys4 = NULL;
938 tp->md5sig_info->alloced4 = 0;
939 } else if (tp->md5sig_info->entries4 != i) {
940 /* Need to do some manipulation */
941 memcpy(&tp->md5sig_info->keys4[i],
942 &tp->md5sig_info->keys4[i+1],
943 (tp->md5sig_info->entries4 - i) *
944 sizeof(struct tcp4_md5sig_key));
945 }
946 tcp_free_md5sig_pool();
947 return 0;
948 }
949 }
950 return -ENOENT;
951 }
952
953 EXPORT_SYMBOL(tcp_v4_md5_do_del);
954
955 static void tcp_v4_clear_md5_list(struct sock *sk)
956 {
957 struct tcp_sock *tp = tcp_sk(sk);
958
959 /* Free each key, then the set of key keys,
960 * the crypto element, and then decrement our
961 * hold on the last resort crypto.
962 */
963 if (tp->md5sig_info->entries4) {
964 int i;
965 for (i = 0; i < tp->md5sig_info->entries4; i++)
966 kfree(tp->md5sig_info->keys4[i].base.key);
967 tp->md5sig_info->entries4 = 0;
968 tcp_free_md5sig_pool();
969 }
970 if (tp->md5sig_info->keys4) {
971 kfree(tp->md5sig_info->keys4);
972 tp->md5sig_info->keys4 = NULL;
973 tp->md5sig_info->alloced4 = 0;
974 }
975 }
976
977 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
978 int optlen)
979 {
980 struct tcp_md5sig cmd;
981 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
982 u8 *newkey;
983
984 if (optlen < sizeof(cmd))
985 return -EINVAL;
986
987 if (copy_from_user(&cmd, optval, sizeof(cmd)))
988 return -EFAULT;
989
990 if (sin->sin_family != AF_INET)
991 return -EINVAL;
992
993 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
994 if (!tcp_sk(sk)->md5sig_info)
995 return -ENOENT;
996 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
997 }
998
999 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1000 return -EINVAL;
1001
1002 if (!tcp_sk(sk)->md5sig_info) {
1003 struct tcp_sock *tp = tcp_sk(sk);
1004 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
1005
1006 if (!p)
1007 return -EINVAL;
1008
1009 tp->md5sig_info = p;
1010 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1011 }
1012
1013 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1014 if (!newkey)
1015 return -ENOMEM;
1016 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1017 newkey, cmd.tcpm_keylen);
1018 }
1019
1020 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1021 __be32 saddr, __be32 daddr,
1022 struct tcphdr *th, int protocol,
1023 int tcplen)
1024 {
1025 struct scatterlist sg[4];
1026 __u16 data_len;
1027 int block = 0;
1028 __sum16 old_checksum;
1029 struct tcp_md5sig_pool *hp;
1030 struct tcp4_pseudohdr *bp;
1031 struct hash_desc *desc;
1032 int err;
1033 unsigned int nbytes = 0;
1034
1035 /*
1036 * Okay, so RFC2385 is turned on for this connection,
1037 * so we need to generate the MD5 hash for the packet now.
1038 */
1039
1040 hp = tcp_get_md5sig_pool();
1041 if (!hp)
1042 goto clear_hash_noput;
1043
1044 bp = &hp->md5_blk.ip4;
1045 desc = &hp->md5_desc;
1046
1047 /*
1048 * 1. the TCP pseudo-header (in the order: source IP address,
1049 * destination IP address, zero-padded protocol number, and
1050 * segment length)
1051 */
1052 bp->saddr = saddr;
1053 bp->daddr = daddr;
1054 bp->pad = 0;
1055 bp->protocol = protocol;
1056 bp->len = htons(tcplen);
1057 sg_set_buf(&sg[block++], bp, sizeof(*bp));
1058 nbytes += sizeof(*bp);
1059
1060 /* 2. the TCP header, excluding options, and assuming a
1061 * checksum of zero/
1062 */
1063 old_checksum = th->check;
1064 th->check = 0;
1065 sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
1066 nbytes += sizeof(struct tcphdr);
1067
1068 /* 3. the TCP segment data (if any) */
1069 data_len = tcplen - (th->doff << 2);
1070 if (data_len > 0) {
1071 unsigned char *data = (unsigned char *)th + (th->doff << 2);
1072 sg_set_buf(&sg[block++], data, data_len);
1073 nbytes += data_len;
1074 }
1075
1076 /* 4. an independently-specified key or password, known to both
1077 * TCPs and presumably connection-specific
1078 */
1079 sg_set_buf(&sg[block++], key->key, key->keylen);
1080 nbytes += key->keylen;
1081
1082 /* Now store the Hash into the packet */
1083 err = crypto_hash_init(desc);
1084 if (err)
1085 goto clear_hash;
1086 err = crypto_hash_update(desc, sg, nbytes);
1087 if (err)
1088 goto clear_hash;
1089 err = crypto_hash_final(desc, md5_hash);
1090 if (err)
1091 goto clear_hash;
1092
1093 /* Reset header, and free up the crypto */
1094 tcp_put_md5sig_pool();
1095 th->check = old_checksum;
1096
1097 out:
1098 return 0;
1099 clear_hash:
1100 tcp_put_md5sig_pool();
1101 clear_hash_noput:
1102 memset(md5_hash, 0, 16);
1103 goto out;
1104 }
1105
1106 int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1107 struct sock *sk,
1108 struct dst_entry *dst,
1109 struct request_sock *req,
1110 struct tcphdr *th, int protocol,
1111 int tcplen)
1112 {
1113 __be32 saddr, daddr;
1114
1115 if (sk) {
1116 saddr = inet_sk(sk)->saddr;
1117 daddr = inet_sk(sk)->daddr;
1118 } else {
1119 struct rtable *rt = (struct rtable *)dst;
1120 BUG_ON(!rt);
1121 saddr = rt->rt_src;
1122 daddr = rt->rt_dst;
1123 }
1124 return tcp_v4_do_calc_md5_hash(md5_hash, key,
1125 saddr, daddr,
1126 th, protocol, tcplen);
1127 }
1128
1129 EXPORT_SYMBOL(tcp_v4_calc_md5_hash);
1130
1131 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1132 {
1133 /*
1134 * This gets called for each TCP segment that arrives
1135 * so we want to be efficient.
1136 * We have 3 drop cases:
1137 * o No MD5 hash and one expected.
1138 * o MD5 hash and we're not expecting one.
1139 * o MD5 hash and its wrong.
1140 */
1141 __u8 *hash_location = NULL;
1142 struct tcp_md5sig_key *hash_expected;
1143 const struct iphdr *iph = ip_hdr(skb);
1144 struct tcphdr *th = tcp_hdr(skb);
1145 int length = (th->doff << 2) - sizeof(struct tcphdr);
1146 int genhash;
1147 unsigned char *ptr;
1148 unsigned char newhash[16];
1149
1150 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1151
1152 /*
1153 * If the TCP option length is less than the TCP_MD5SIG
1154 * option length, then we can shortcut
1155 */
1156 if (length < TCPOLEN_MD5SIG) {
1157 if (hash_expected)
1158 return 1;
1159 else
1160 return 0;
1161 }
1162
1163 /* Okay, we can't shortcut - we have to grub through the options */
1164 ptr = (unsigned char *)(th + 1);
1165 while (length > 0) {
1166 int opcode = *ptr++;
1167 int opsize;
1168
1169 switch (opcode) {
1170 case TCPOPT_EOL:
1171 goto done_opts;
1172 case TCPOPT_NOP:
1173 length--;
1174 continue;
1175 default:
1176 opsize = *ptr++;
1177 if (opsize < 2)
1178 goto done_opts;
1179 if (opsize > length)
1180 goto done_opts;
1181
1182 if (opcode == TCPOPT_MD5SIG) {
1183 hash_location = ptr;
1184 goto done_opts;
1185 }
1186 }
1187 ptr += opsize-2;
1188 length -= opsize;
1189 }
1190 done_opts:
1191 /* We've parsed the options - do we have a hash? */
1192 if (!hash_expected && !hash_location)
1193 return 0;
1194
1195 if (hash_expected && !hash_location) {
1196 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
1197 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1198 NIPQUAD(iph->saddr), ntohs(th->source),
1199 NIPQUAD(iph->daddr), ntohs(th->dest));
1200 return 1;
1201 }
1202
1203 if (!hash_expected && hash_location) {
1204 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
1205 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1206 NIPQUAD(iph->saddr), ntohs(th->source),
1207 NIPQUAD(iph->daddr), ntohs(th->dest));
1208 return 1;
1209 }
1210
1211 /* Okay, so this is hash_expected and hash_location -
1212 * so we need to calculate the checksum.
1213 */
1214 genhash = tcp_v4_do_calc_md5_hash(newhash,
1215 hash_expected,
1216 iph->saddr, iph->daddr,
1217 th, sk->sk_protocol,
1218 skb->len);
1219
1220 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1221 if (net_ratelimit()) {
1222 printk(KERN_INFO "MD5 Hash failed for "
1223 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
1224 NIPQUAD(iph->saddr), ntohs(th->source),
1225 NIPQUAD(iph->daddr), ntohs(th->dest),
1226 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1227 }
1228 return 1;
1229 }
1230 return 0;
1231 }
1232
1233 #endif
1234
1235 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1236 .family = PF_INET,
1237 .obj_size = sizeof(struct tcp_request_sock),
1238 .rtx_syn_ack = tcp_v4_send_synack,
1239 .send_ack = tcp_v4_reqsk_send_ack,
1240 .destructor = tcp_v4_reqsk_destructor,
1241 .send_reset = tcp_v4_send_reset,
1242 };
1243
1244 #ifdef CONFIG_TCP_MD5SIG
1245 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1246 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1247 };
1248 #endif
1249
1250 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1251 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1252 .twsk_unique = tcp_twsk_unique,
1253 .twsk_destructor= tcp_twsk_destructor,
1254 };
1255
1256 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1257 {
1258 struct inet_request_sock *ireq;
1259 struct tcp_options_received tmp_opt;
1260 struct request_sock *req;
1261 __be32 saddr = ip_hdr(skb)->saddr;
1262 __be32 daddr = ip_hdr(skb)->daddr;
1263 __u32 isn = TCP_SKB_CB(skb)->when;
1264 struct dst_entry *dst = NULL;
1265 #ifdef CONFIG_SYN_COOKIES
1266 int want_cookie = 0;
1267 #else
1268 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1269 #endif
1270
1271 /* Never answer to SYNs send to broadcast or multicast */
1272 if (((struct rtable *)skb->dst)->rt_flags &
1273 (RTCF_BROADCAST | RTCF_MULTICAST))
1274 goto drop;
1275
1276 /* TW buckets are converted to open requests without
1277 * limitations, they conserve resources and peer is
1278 * evidently real one.
1279 */
1280 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1281 #ifdef CONFIG_SYN_COOKIES
1282 if (sysctl_tcp_syncookies) {
1283 want_cookie = 1;
1284 } else
1285 #endif
1286 goto drop;
1287 }
1288
1289 /* Accept backlog is full. If we have already queued enough
1290 * of warm entries in syn queue, drop request. It is better than
1291 * clogging syn queue with openreqs with exponentially increasing
1292 * timeout.
1293 */
1294 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1295 goto drop;
1296
1297 req = reqsk_alloc(&tcp_request_sock_ops);
1298 if (!req)
1299 goto drop;
1300
1301 #ifdef CONFIG_TCP_MD5SIG
1302 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1303 #endif
1304
1305 tcp_clear_options(&tmp_opt);
1306 tmp_opt.mss_clamp = 536;
1307 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1308
1309 tcp_parse_options(skb, &tmp_opt, 0);
1310
1311 if (want_cookie) {
1312 tcp_clear_options(&tmp_opt);
1313 tmp_opt.saw_tstamp = 0;
1314 }
1315
1316 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1317 /* Some OSes (unknown ones, but I see them on web server, which
1318 * contains information interesting only for windows'
1319 * users) do not send their stamp in SYN. It is easy case.
1320 * We simply do not advertise TS support.
1321 */
1322 tmp_opt.saw_tstamp = 0;
1323 tmp_opt.tstamp_ok = 0;
1324 }
1325 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1326
1327 tcp_openreq_init(req, &tmp_opt, skb);
1328
1329 if (security_inet_conn_request(sk, skb, req))
1330 goto drop_and_free;
1331
1332 ireq = inet_rsk(req);
1333 ireq->loc_addr = daddr;
1334 ireq->rmt_addr = saddr;
1335 ireq->opt = tcp_v4_save_options(sk, skb);
1336 if (!want_cookie)
1337 TCP_ECN_create_request(req, tcp_hdr(skb));
1338
1339 if (want_cookie) {
1340 #ifdef CONFIG_SYN_COOKIES
1341 syn_flood_warning(skb);
1342 #endif
1343 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1344 } else if (!isn) {
1345 struct inet_peer *peer = NULL;
1346
1347 /* VJ's idea. We save last timestamp seen
1348 * from the destination in peer table, when entering
1349 * state TIME-WAIT, and check against it before
1350 * accepting new connection request.
1351 *
1352 * If "isn" is not zero, this request hit alive
1353 * timewait bucket, so that all the necessary checks
1354 * are made in the function processing timewait state.
1355 */
1356 if (tmp_opt.saw_tstamp &&
1357 tcp_death_row.sysctl_tw_recycle &&
1358 (dst = inet_csk_route_req(sk, req)) != NULL &&
1359 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1360 peer->v4daddr == saddr) {
1361 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1362 (s32)(peer->tcp_ts - req->ts_recent) >
1363 TCP_PAWS_WINDOW) {
1364 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1365 dst_release(dst);
1366 goto drop_and_free;
1367 }
1368 }
1369 /* Kill the following clause, if you dislike this way. */
1370 else if (!sysctl_tcp_syncookies &&
1371 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1372 (sysctl_max_syn_backlog >> 2)) &&
1373 (!peer || !peer->tcp_ts_stamp) &&
1374 (!dst || !dst_metric(dst, RTAX_RTT))) {
1375 /* Without syncookies last quarter of
1376 * backlog is filled with destinations,
1377 * proven to be alive.
1378 * It means that we continue to communicate
1379 * to destinations, already remembered
1380 * to the moment of synflood.
1381 */
1382 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
1383 "request from %u.%u.%u.%u/%u\n",
1384 NIPQUAD(saddr),
1385 ntohs(tcp_hdr(skb)->source));
1386 dst_release(dst);
1387 goto drop_and_free;
1388 }
1389
1390 isn = tcp_v4_init_sequence(skb);
1391 }
1392 tcp_rsk(req)->snt_isn = isn;
1393
1394 if (tcp_v4_send_synack(sk, req, dst))
1395 goto drop_and_free;
1396
1397 if (want_cookie) {
1398 reqsk_free(req);
1399 } else {
1400 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1401 }
1402 return 0;
1403
1404 drop_and_free:
1405 reqsk_free(req);
1406 drop:
1407 return 0;
1408 }
1409
1410
1411 /*
1412 * The three way handshake has completed - we got a valid synack -
1413 * now create the new socket.
1414 */
1415 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1416 struct request_sock *req,
1417 struct dst_entry *dst)
1418 {
1419 struct inet_request_sock *ireq;
1420 struct inet_sock *newinet;
1421 struct tcp_sock *newtp;
1422 struct sock *newsk;
1423 #ifdef CONFIG_TCP_MD5SIG
1424 struct tcp_md5sig_key *key;
1425 #endif
1426
1427 if (sk_acceptq_is_full(sk))
1428 goto exit_overflow;
1429
1430 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1431 goto exit;
1432
1433 newsk = tcp_create_openreq_child(sk, req, skb);
1434 if (!newsk)
1435 goto exit;
1436
1437 newsk->sk_gso_type = SKB_GSO_TCPV4;
1438 sk_setup_caps(newsk, dst);
1439
1440 newtp = tcp_sk(newsk);
1441 newinet = inet_sk(newsk);
1442 ireq = inet_rsk(req);
1443 newinet->daddr = ireq->rmt_addr;
1444 newinet->rcv_saddr = ireq->loc_addr;
1445 newinet->saddr = ireq->loc_addr;
1446 newinet->opt = ireq->opt;
1447 ireq->opt = NULL;
1448 newinet->mc_index = inet_iif(skb);
1449 newinet->mc_ttl = ip_hdr(skb)->ttl;
1450 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1451 if (newinet->opt)
1452 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1453 newinet->id = newtp->write_seq ^ jiffies;
1454
1455 tcp_mtup_init(newsk);
1456 tcp_sync_mss(newsk, dst_mtu(dst));
1457 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1458 tcp_initialize_rcv_mss(newsk);
1459
1460 #ifdef CONFIG_TCP_MD5SIG
1461 /* Copy over the MD5 key from the original socket */
1462 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1463 /*
1464 * We're using one, so create a matching key
1465 * on the newsk structure. If we fail to get
1466 * memory, then we end up not copying the key
1467 * across. Shucks.
1468 */
1469 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1470 if (newkey != NULL)
1471 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1472 newkey, key->keylen);
1473 }
1474 #endif
1475
1476 __inet_hash(&tcp_hashinfo, newsk, 0);
1477 __inet_inherit_port(&tcp_hashinfo, sk, newsk);
1478
1479 return newsk;
1480
1481 exit_overflow:
1482 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1483 exit:
1484 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1485 dst_release(dst);
1486 return NULL;
1487 }
1488
1489 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1490 {
1491 struct tcphdr *th = tcp_hdr(skb);
1492 const struct iphdr *iph = ip_hdr(skb);
1493 struct sock *nsk;
1494 struct request_sock **prev;
1495 /* Find possible connection requests. */
1496 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1497 iph->saddr, iph->daddr);
1498 if (req)
1499 return tcp_check_req(sk, skb, req, prev);
1500
1501 nsk = inet_lookup_established(&tcp_hashinfo, iph->saddr, th->source,
1502 iph->daddr, th->dest, inet_iif(skb));
1503
1504 if (nsk) {
1505 if (nsk->sk_state != TCP_TIME_WAIT) {
1506 bh_lock_sock(nsk);
1507 return nsk;
1508 }
1509 inet_twsk_put(inet_twsk(nsk));
1510 return NULL;
1511 }
1512
1513 #ifdef CONFIG_SYN_COOKIES
1514 if (!th->rst && !th->syn && th->ack)
1515 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1516 #endif
1517 return sk;
1518 }
1519
1520 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1521 {
1522 const struct iphdr *iph = ip_hdr(skb);
1523
1524 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1525 if (!tcp_v4_check(skb->len, iph->saddr,
1526 iph->daddr, skb->csum)) {
1527 skb->ip_summed = CHECKSUM_UNNECESSARY;
1528 return 0;
1529 }
1530 }
1531
1532 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1533 skb->len, IPPROTO_TCP, 0);
1534
1535 if (skb->len <= 76) {
1536 return __skb_checksum_complete(skb);
1537 }
1538 return 0;
1539 }
1540
1541
1542 /* The socket must have it's spinlock held when we get
1543 * here.
1544 *
1545 * We have a potential double-lock case here, so even when
1546 * doing backlog processing we use the BH locking scheme.
1547 * This is because we cannot sleep with the original spinlock
1548 * held.
1549 */
1550 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1551 {
1552 struct sock *rsk;
1553 #ifdef CONFIG_TCP_MD5SIG
1554 /*
1555 * We really want to reject the packet as early as possible
1556 * if:
1557 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1558 * o There is an MD5 option and we're not expecting one
1559 */
1560 if (tcp_v4_inbound_md5_hash(sk, skb))
1561 goto discard;
1562 #endif
1563
1564 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1565 TCP_CHECK_TIMER(sk);
1566 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1567 rsk = sk;
1568 goto reset;
1569 }
1570 TCP_CHECK_TIMER(sk);
1571 return 0;
1572 }
1573
1574 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1575 goto csum_err;
1576
1577 if (sk->sk_state == TCP_LISTEN) {
1578 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1579 if (!nsk)
1580 goto discard;
1581
1582 if (nsk != sk) {
1583 if (tcp_child_process(sk, nsk, skb)) {
1584 rsk = nsk;
1585 goto reset;
1586 }
1587 return 0;
1588 }
1589 }
1590
1591 TCP_CHECK_TIMER(sk);
1592 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1593 rsk = sk;
1594 goto reset;
1595 }
1596 TCP_CHECK_TIMER(sk);
1597 return 0;
1598
1599 reset:
1600 tcp_v4_send_reset(rsk, skb);
1601 discard:
1602 kfree_skb(skb);
1603 /* Be careful here. If this function gets more complicated and
1604 * gcc suffers from register pressure on the x86, sk (in %ebx)
1605 * might be destroyed here. This current version compiles correctly,
1606 * but you have been warned.
1607 */
1608 return 0;
1609
1610 csum_err:
1611 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1612 goto discard;
1613 }
1614
1615 /*
1616 * From tcp_input.c
1617 */
1618
1619 int tcp_v4_rcv(struct sk_buff *skb)
1620 {
1621 const struct iphdr *iph;
1622 struct tcphdr *th;
1623 struct sock *sk;
1624 int ret;
1625
1626 if (skb->pkt_type != PACKET_HOST)
1627 goto discard_it;
1628
1629 /* Count it even if it's bad */
1630 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1631
1632 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1633 goto discard_it;
1634
1635 th = tcp_hdr(skb);
1636
1637 if (th->doff < sizeof(struct tcphdr) / 4)
1638 goto bad_packet;
1639 if (!pskb_may_pull(skb, th->doff * 4))
1640 goto discard_it;
1641
1642 /* An explanation is required here, I think.
1643 * Packet length and doff are validated by header prediction,
1644 * provided case of th->doff==0 is eliminated.
1645 * So, we defer the checks. */
1646 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1647 goto bad_packet;
1648
1649 th = tcp_hdr(skb);
1650 iph = ip_hdr(skb);
1651 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1652 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1653 skb->len - th->doff * 4);
1654 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1655 TCP_SKB_CB(skb)->when = 0;
1656 TCP_SKB_CB(skb)->flags = iph->tos;
1657 TCP_SKB_CB(skb)->sacked = 0;
1658
1659 sk = __inet_lookup(&tcp_hashinfo, iph->saddr, th->source,
1660 iph->daddr, th->dest, inet_iif(skb));
1661 if (!sk)
1662 goto no_tcp_socket;
1663
1664 process:
1665 if (sk->sk_state == TCP_TIME_WAIT)
1666 goto do_time_wait;
1667
1668 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1669 goto discard_and_relse;
1670 nf_reset(skb);
1671
1672 if (sk_filter(sk, skb))
1673 goto discard_and_relse;
1674
1675 skb->dev = NULL;
1676
1677 bh_lock_sock_nested(sk);
1678 ret = 0;
1679 if (!sock_owned_by_user(sk)) {
1680 #ifdef CONFIG_NET_DMA
1681 struct tcp_sock *tp = tcp_sk(sk);
1682 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1683 tp->ucopy.dma_chan = get_softnet_dma();
1684 if (tp->ucopy.dma_chan)
1685 ret = tcp_v4_do_rcv(sk, skb);
1686 else
1687 #endif
1688 {
1689 if (!tcp_prequeue(sk, skb))
1690 ret = tcp_v4_do_rcv(sk, skb);
1691 }
1692 } else
1693 sk_add_backlog(sk, skb);
1694 bh_unlock_sock(sk);
1695
1696 sock_put(sk);
1697
1698 return ret;
1699
1700 no_tcp_socket:
1701 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1702 goto discard_it;
1703
1704 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1705 bad_packet:
1706 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1707 } else {
1708 tcp_v4_send_reset(NULL, skb);
1709 }
1710
1711 discard_it:
1712 /* Discard frame. */
1713 kfree_skb(skb);
1714 return 0;
1715
1716 discard_and_relse:
1717 sock_put(sk);
1718 goto discard_it;
1719
1720 do_time_wait:
1721 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1722 inet_twsk_put(inet_twsk(sk));
1723 goto discard_it;
1724 }
1725
1726 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1727 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1728 inet_twsk_put(inet_twsk(sk));
1729 goto discard_it;
1730 }
1731 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1732 case TCP_TW_SYN: {
1733 struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
1734 iph->daddr, th->dest,
1735 inet_iif(skb));
1736 if (sk2) {
1737 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1738 inet_twsk_put(inet_twsk(sk));
1739 sk = sk2;
1740 goto process;
1741 }
1742 /* Fall through to ACK */
1743 }
1744 case TCP_TW_ACK:
1745 tcp_v4_timewait_ack(sk, skb);
1746 break;
1747 case TCP_TW_RST:
1748 goto no_tcp_socket;
1749 case TCP_TW_SUCCESS:;
1750 }
1751 goto discard_it;
1752 }
1753
1754 /* VJ's idea. Save last timestamp seen from this destination
1755 * and hold it at least for normal timewait interval to use for duplicate
1756 * segment detection in subsequent connections, before they enter synchronized
1757 * state.
1758 */
1759
1760 int tcp_v4_remember_stamp(struct sock *sk)
1761 {
1762 struct inet_sock *inet = inet_sk(sk);
1763 struct tcp_sock *tp = tcp_sk(sk);
1764 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1765 struct inet_peer *peer = NULL;
1766 int release_it = 0;
1767
1768 if (!rt || rt->rt_dst != inet->daddr) {
1769 peer = inet_getpeer(inet->daddr, 1);
1770 release_it = 1;
1771 } else {
1772 if (!rt->peer)
1773 rt_bind_peer(rt, 1);
1774 peer = rt->peer;
1775 }
1776
1777 if (peer) {
1778 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1779 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1780 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1781 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1782 peer->tcp_ts = tp->rx_opt.ts_recent;
1783 }
1784 if (release_it)
1785 inet_putpeer(peer);
1786 return 1;
1787 }
1788
1789 return 0;
1790 }
1791
1792 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1793 {
1794 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1795
1796 if (peer) {
1797 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1798
1799 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1800 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1801 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1802 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1803 peer->tcp_ts = tcptw->tw_ts_recent;
1804 }
1805 inet_putpeer(peer);
1806 return 1;
1807 }
1808
1809 return 0;
1810 }
1811
1812 struct inet_connection_sock_af_ops ipv4_specific = {
1813 .queue_xmit = ip_queue_xmit,
1814 .send_check = tcp_v4_send_check,
1815 .rebuild_header = inet_sk_rebuild_header,
1816 .conn_request = tcp_v4_conn_request,
1817 .syn_recv_sock = tcp_v4_syn_recv_sock,
1818 .remember_stamp = tcp_v4_remember_stamp,
1819 .net_header_len = sizeof(struct iphdr),
1820 .setsockopt = ip_setsockopt,
1821 .getsockopt = ip_getsockopt,
1822 .addr2sockaddr = inet_csk_addr2sockaddr,
1823 .sockaddr_len = sizeof(struct sockaddr_in),
1824 #ifdef CONFIG_COMPAT
1825 .compat_setsockopt = compat_ip_setsockopt,
1826 .compat_getsockopt = compat_ip_getsockopt,
1827 #endif
1828 };
1829
1830 #ifdef CONFIG_TCP_MD5SIG
1831 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1832 .md5_lookup = tcp_v4_md5_lookup,
1833 .calc_md5_hash = tcp_v4_calc_md5_hash,
1834 .md5_add = tcp_v4_md5_add_func,
1835 .md5_parse = tcp_v4_parse_md5_keys,
1836 };
1837 #endif
1838
1839 /* NOTE: A lot of things set to zero explicitly by call to
1840 * sk_alloc() so need not be done here.
1841 */
1842 static int tcp_v4_init_sock(struct sock *sk)
1843 {
1844 struct inet_connection_sock *icsk = inet_csk(sk);
1845 struct tcp_sock *tp = tcp_sk(sk);
1846
1847 skb_queue_head_init(&tp->out_of_order_queue);
1848 tcp_init_xmit_timers(sk);
1849 tcp_prequeue_init(tp);
1850
1851 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1852 tp->mdev = TCP_TIMEOUT_INIT;
1853
1854 /* So many TCP implementations out there (incorrectly) count the
1855 * initial SYN frame in their delayed-ACK and congestion control
1856 * algorithms that we must have the following bandaid to talk
1857 * efficiently to them. -DaveM
1858 */
1859 tp->snd_cwnd = 2;
1860
1861 /* See draft-stevens-tcpca-spec-01 for discussion of the
1862 * initialization of these values.
1863 */
1864 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1865 tp->snd_cwnd_clamp = ~0;
1866 tp->mss_cache = 536;
1867
1868 tp->reordering = sysctl_tcp_reordering;
1869 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1870
1871 sk->sk_state = TCP_CLOSE;
1872
1873 sk->sk_write_space = sk_stream_write_space;
1874 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1875
1876 icsk->icsk_af_ops = &ipv4_specific;
1877 icsk->icsk_sync_mss = tcp_sync_mss;
1878 #ifdef CONFIG_TCP_MD5SIG
1879 tp->af_specific = &tcp_sock_ipv4_specific;
1880 #endif
1881
1882 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1883 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1884
1885 atomic_inc(&tcp_sockets_allocated);
1886
1887 return 0;
1888 }
1889
1890 int tcp_v4_destroy_sock(struct sock *sk)
1891 {
1892 struct tcp_sock *tp = tcp_sk(sk);
1893
1894 tcp_clear_xmit_timers(sk);
1895
1896 tcp_cleanup_congestion_control(sk);
1897
1898 /* Cleanup up the write buffer. */
1899 tcp_write_queue_purge(sk);
1900
1901 /* Cleans up our, hopefully empty, out_of_order_queue. */
1902 __skb_queue_purge(&tp->out_of_order_queue);
1903
1904 #ifdef CONFIG_TCP_MD5SIG
1905 /* Clean up the MD5 key list, if any */
1906 if (tp->md5sig_info) {
1907 tcp_v4_clear_md5_list(sk);
1908 kfree(tp->md5sig_info);
1909 tp->md5sig_info = NULL;
1910 }
1911 #endif
1912
1913 #ifdef CONFIG_NET_DMA
1914 /* Cleans up our sk_async_wait_queue */
1915 __skb_queue_purge(&sk->sk_async_wait_queue);
1916 #endif
1917
1918 /* Clean prequeue, it must be empty really */
1919 __skb_queue_purge(&tp->ucopy.prequeue);
1920
1921 /* Clean up a referenced TCP bind bucket. */
1922 if (inet_csk(sk)->icsk_bind_hash)
1923 inet_put_port(&tcp_hashinfo, sk);
1924
1925 /*
1926 * If sendmsg cached page exists, toss it.
1927 */
1928 if (sk->sk_sndmsg_page) {
1929 __free_page(sk->sk_sndmsg_page);
1930 sk->sk_sndmsg_page = NULL;
1931 }
1932
1933 atomic_dec(&tcp_sockets_allocated);
1934
1935 return 0;
1936 }
1937
1938 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1939
1940 #ifdef CONFIG_PROC_FS
1941 /* Proc filesystem TCP sock list dumping. */
1942
1943 static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1944 {
1945 return hlist_empty(head) ? NULL :
1946 list_entry(head->first, struct inet_timewait_sock, tw_node);
1947 }
1948
1949 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1950 {
1951 return tw->tw_node.next ?
1952 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1953 }
1954
1955 static void *listening_get_next(struct seq_file *seq, void *cur)
1956 {
1957 struct inet_connection_sock *icsk;
1958 struct hlist_node *node;
1959 struct sock *sk = cur;
1960 struct tcp_iter_state* st = seq->private;
1961
1962 if (!sk) {
1963 st->bucket = 0;
1964 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1965 goto get_sk;
1966 }
1967
1968 ++st->num;
1969
1970 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1971 struct request_sock *req = cur;
1972
1973 icsk = inet_csk(st->syn_wait_sk);
1974 req = req->dl_next;
1975 while (1) {
1976 while (req) {
1977 if (req->rsk_ops->family == st->family) {
1978 cur = req;
1979 goto out;
1980 }
1981 req = req->dl_next;
1982 }
1983 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1984 break;
1985 get_req:
1986 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1987 }
1988 sk = sk_next(st->syn_wait_sk);
1989 st->state = TCP_SEQ_STATE_LISTENING;
1990 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1991 } else {
1992 icsk = inet_csk(sk);
1993 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1994 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1995 goto start_req;
1996 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1997 sk = sk_next(sk);
1998 }
1999 get_sk:
2000 sk_for_each_from(sk, node) {
2001 if (sk->sk_family == st->family) {
2002 cur = sk;
2003 goto out;
2004 }
2005 icsk = inet_csk(sk);
2006 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2007 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2008 start_req:
2009 st->uid = sock_i_uid(sk);
2010 st->syn_wait_sk = sk;
2011 st->state = TCP_SEQ_STATE_OPENREQ;
2012 st->sbucket = 0;
2013 goto get_req;
2014 }
2015 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2016 }
2017 if (++st->bucket < INET_LHTABLE_SIZE) {
2018 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
2019 goto get_sk;
2020 }
2021 cur = NULL;
2022 out:
2023 return cur;
2024 }
2025
2026 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2027 {
2028 void *rc = listening_get_next(seq, NULL);
2029
2030 while (rc && *pos) {
2031 rc = listening_get_next(seq, rc);
2032 --*pos;
2033 }
2034 return rc;
2035 }
2036
2037 static void *established_get_first(struct seq_file *seq)
2038 {
2039 struct tcp_iter_state* st = seq->private;
2040 void *rc = NULL;
2041
2042 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2043 struct sock *sk;
2044 struct hlist_node *node;
2045 struct inet_timewait_sock *tw;
2046
2047 read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2048 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2049 if (sk->sk_family != st->family) {
2050 continue;
2051 }
2052 rc = sk;
2053 goto out;
2054 }
2055 st->state = TCP_SEQ_STATE_TIME_WAIT;
2056 inet_twsk_for_each(tw, node,
2057 &tcp_hashinfo.ehash[st->bucket].twchain) {
2058 if (tw->tw_family != st->family) {
2059 continue;
2060 }
2061 rc = tw;
2062 goto out;
2063 }
2064 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2065 st->state = TCP_SEQ_STATE_ESTABLISHED;
2066 }
2067 out:
2068 return rc;
2069 }
2070
2071 static void *established_get_next(struct seq_file *seq, void *cur)
2072 {
2073 struct sock *sk = cur;
2074 struct inet_timewait_sock *tw;
2075 struct hlist_node *node;
2076 struct tcp_iter_state* st = seq->private;
2077
2078 ++st->num;
2079
2080 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2081 tw = cur;
2082 tw = tw_next(tw);
2083 get_tw:
2084 while (tw && tw->tw_family != st->family) {
2085 tw = tw_next(tw);
2086 }
2087 if (tw) {
2088 cur = tw;
2089 goto out;
2090 }
2091 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2092 st->state = TCP_SEQ_STATE_ESTABLISHED;
2093
2094 if (++st->bucket < tcp_hashinfo.ehash_size) {
2095 read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2096 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
2097 } else {
2098 cur = NULL;
2099 goto out;
2100 }
2101 } else
2102 sk = sk_next(sk);
2103
2104 sk_for_each_from(sk, node) {
2105 if (sk->sk_family == st->family)
2106 goto found;
2107 }
2108
2109 st->state = TCP_SEQ_STATE_TIME_WAIT;
2110 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2111 goto get_tw;
2112 found:
2113 cur = sk;
2114 out:
2115 return cur;
2116 }
2117
2118 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2119 {
2120 void *rc = established_get_first(seq);
2121
2122 while (rc && pos) {
2123 rc = established_get_next(seq, rc);
2124 --pos;
2125 }
2126 return rc;
2127 }
2128
2129 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2130 {
2131 void *rc;
2132 struct tcp_iter_state* st = seq->private;
2133
2134 inet_listen_lock(&tcp_hashinfo);
2135 st->state = TCP_SEQ_STATE_LISTENING;
2136 rc = listening_get_idx(seq, &pos);
2137
2138 if (!rc) {
2139 inet_listen_unlock(&tcp_hashinfo);
2140 st->state = TCP_SEQ_STATE_ESTABLISHED;
2141 rc = established_get_idx(seq, pos);
2142 }
2143
2144 return rc;
2145 }
2146
2147 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2148 {
2149 struct tcp_iter_state* st = seq->private;
2150 st->state = TCP_SEQ_STATE_LISTENING;
2151 st->num = 0;
2152 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2153 }
2154
2155 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2156 {
2157 void *rc = NULL;
2158 struct tcp_iter_state* st;
2159
2160 if (v == SEQ_START_TOKEN) {
2161 rc = tcp_get_idx(seq, 0);
2162 goto out;
2163 }
2164 st = seq->private;
2165
2166 switch (st->state) {
2167 case TCP_SEQ_STATE_OPENREQ:
2168 case TCP_SEQ_STATE_LISTENING:
2169 rc = listening_get_next(seq, v);
2170 if (!rc) {
2171 inet_listen_unlock(&tcp_hashinfo);
2172 st->state = TCP_SEQ_STATE_ESTABLISHED;
2173 rc = established_get_first(seq);
2174 }
2175 break;
2176 case TCP_SEQ_STATE_ESTABLISHED:
2177 case TCP_SEQ_STATE_TIME_WAIT:
2178 rc = established_get_next(seq, v);
2179 break;
2180 }
2181 out:
2182 ++*pos;
2183 return rc;
2184 }
2185
2186 static void tcp_seq_stop(struct seq_file *seq, void *v)
2187 {
2188 struct tcp_iter_state* st = seq->private;
2189
2190 switch (st->state) {
2191 case TCP_SEQ_STATE_OPENREQ:
2192 if (v) {
2193 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2194 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2195 }
2196 case TCP_SEQ_STATE_LISTENING:
2197 if (v != SEQ_START_TOKEN)
2198 inet_listen_unlock(&tcp_hashinfo);
2199 break;
2200 case TCP_SEQ_STATE_TIME_WAIT:
2201 case TCP_SEQ_STATE_ESTABLISHED:
2202 if (v)
2203 read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock);
2204 break;
2205 }
2206 }
2207
2208 static int tcp_seq_open(struct inode *inode, struct file *file)
2209 {
2210 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2211 struct seq_file *seq;
2212 struct tcp_iter_state *s;
2213 int rc;
2214
2215 if (unlikely(afinfo == NULL))
2216 return -EINVAL;
2217
2218 s = kzalloc(sizeof(*s), GFP_KERNEL);
2219 if (!s)
2220 return -ENOMEM;
2221 s->family = afinfo->family;
2222 s->seq_ops.start = tcp_seq_start;
2223 s->seq_ops.next = tcp_seq_next;
2224 s->seq_ops.show = afinfo->seq_show;
2225 s->seq_ops.stop = tcp_seq_stop;
2226
2227 rc = seq_open(file, &s->seq_ops);
2228 if (rc)
2229 goto out_kfree;
2230 seq = file->private_data;
2231 seq->private = s;
2232 out:
2233 return rc;
2234 out_kfree:
2235 kfree(s);
2236 goto out;
2237 }
2238
2239 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
2240 {
2241 int rc = 0;
2242 struct proc_dir_entry *p;
2243
2244 if (!afinfo)
2245 return -EINVAL;
2246 afinfo->seq_fops->owner = afinfo->owner;
2247 afinfo->seq_fops->open = tcp_seq_open;
2248 afinfo->seq_fops->read = seq_read;
2249 afinfo->seq_fops->llseek = seq_lseek;
2250 afinfo->seq_fops->release = seq_release_private;
2251
2252 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
2253 if (p)
2254 p->data = afinfo;
2255 else
2256 rc = -ENOMEM;
2257 return rc;
2258 }
2259
2260 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
2261 {
2262 if (!afinfo)
2263 return;
2264 proc_net_remove(afinfo->name);
2265 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
2266 }
2267
2268 static void get_openreq4(struct sock *sk, struct request_sock *req,
2269 char *tmpbuf, int i, int uid)
2270 {
2271 const struct inet_request_sock *ireq = inet_rsk(req);
2272 int ttd = req->expires - jiffies;
2273
2274 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2275 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
2276 i,
2277 ireq->loc_addr,
2278 ntohs(inet_sk(sk)->sport),
2279 ireq->rmt_addr,
2280 ntohs(ireq->rmt_port),
2281 TCP_SYN_RECV,
2282 0, 0, /* could print option size, but that is af dependent. */
2283 1, /* timers active (only the expire timer) */
2284 jiffies_to_clock_t(ttd),
2285 req->retrans,
2286 uid,
2287 0, /* non standard timer */
2288 0, /* open_requests have no inode */
2289 atomic_read(&sk->sk_refcnt),
2290 req);
2291 }
2292
2293 static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
2294 {
2295 int timer_active;
2296 unsigned long timer_expires;
2297 struct tcp_sock *tp = tcp_sk(sk);
2298 const struct inet_connection_sock *icsk = inet_csk(sk);
2299 struct inet_sock *inet = inet_sk(sk);
2300 __be32 dest = inet->daddr;
2301 __be32 src = inet->rcv_saddr;
2302 __u16 destp = ntohs(inet->dport);
2303 __u16 srcp = ntohs(inet->sport);
2304
2305 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2306 timer_active = 1;
2307 timer_expires = icsk->icsk_timeout;
2308 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2309 timer_active = 4;
2310 timer_expires = icsk->icsk_timeout;
2311 } else if (timer_pending(&sk->sk_timer)) {
2312 timer_active = 2;
2313 timer_expires = sk->sk_timer.expires;
2314 } else {
2315 timer_active = 0;
2316 timer_expires = jiffies;
2317 }
2318
2319 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2320 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
2321 i, src, srcp, dest, destp, sk->sk_state,
2322 tp->write_seq - tp->snd_una,
2323 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2324 (tp->rcv_nxt - tp->copied_seq),
2325 timer_active,
2326 jiffies_to_clock_t(timer_expires - jiffies),
2327 icsk->icsk_retransmits,
2328 sock_i_uid(sk),
2329 icsk->icsk_probes_out,
2330 sock_i_ino(sk),
2331 atomic_read(&sk->sk_refcnt), sk,
2332 icsk->icsk_rto,
2333 icsk->icsk_ack.ato,
2334 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2335 tp->snd_cwnd,
2336 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
2337 }
2338
2339 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2340 char *tmpbuf, int i)
2341 {
2342 __be32 dest, src;
2343 __u16 destp, srcp;
2344 int ttd = tw->tw_ttd - jiffies;
2345
2346 if (ttd < 0)
2347 ttd = 0;
2348
2349 dest = tw->tw_daddr;
2350 src = tw->tw_rcv_saddr;
2351 destp = ntohs(tw->tw_dport);
2352 srcp = ntohs(tw->tw_sport);
2353
2354 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2355 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
2356 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2357 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2358 atomic_read(&tw->tw_refcnt), tw);
2359 }
2360
2361 #define TMPSZ 150
2362
2363 static int tcp4_seq_show(struct seq_file *seq, void *v)
2364 {
2365 struct tcp_iter_state* st;
2366 char tmpbuf[TMPSZ + 1];
2367
2368 if (v == SEQ_START_TOKEN) {
2369 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2370 " sl local_address rem_address st tx_queue "
2371 "rx_queue tr tm->when retrnsmt uid timeout "
2372 "inode");
2373 goto out;
2374 }
2375 st = seq->private;
2376
2377 switch (st->state) {
2378 case TCP_SEQ_STATE_LISTENING:
2379 case TCP_SEQ_STATE_ESTABLISHED:
2380 get_tcp4_sock(v, tmpbuf, st->num);
2381 break;
2382 case TCP_SEQ_STATE_OPENREQ:
2383 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
2384 break;
2385 case TCP_SEQ_STATE_TIME_WAIT:
2386 get_timewait4_sock(v, tmpbuf, st->num);
2387 break;
2388 }
2389 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
2390 out:
2391 return 0;
2392 }
2393
2394 static struct file_operations tcp4_seq_fops;
2395 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2396 .owner = THIS_MODULE,
2397 .name = "tcp",
2398 .family = AF_INET,
2399 .seq_show = tcp4_seq_show,
2400 .seq_fops = &tcp4_seq_fops,
2401 };
2402
2403 int __init tcp4_proc_init(void)
2404 {
2405 return tcp_proc_register(&tcp4_seq_afinfo);
2406 }
2407
2408 void tcp4_proc_exit(void)
2409 {
2410 tcp_proc_unregister(&tcp4_seq_afinfo);
2411 }
2412 #endif /* CONFIG_PROC_FS */
2413
2414 struct proto tcp_prot = {
2415 .name = "TCP",
2416 .owner = THIS_MODULE,
2417 .close = tcp_close,
2418 .connect = tcp_v4_connect,
2419 .disconnect = tcp_disconnect,
2420 .accept = inet_csk_accept,
2421 .ioctl = tcp_ioctl,
2422 .init = tcp_v4_init_sock,
2423 .destroy = tcp_v4_destroy_sock,
2424 .shutdown = tcp_shutdown,
2425 .setsockopt = tcp_setsockopt,
2426 .getsockopt = tcp_getsockopt,
2427 .recvmsg = tcp_recvmsg,
2428 .backlog_rcv = tcp_v4_do_rcv,
2429 .hash = tcp_v4_hash,
2430 .unhash = tcp_unhash,
2431 .get_port = tcp_v4_get_port,
2432 .enter_memory_pressure = tcp_enter_memory_pressure,
2433 .sockets_allocated = &tcp_sockets_allocated,
2434 .orphan_count = &tcp_orphan_count,
2435 .memory_allocated = &tcp_memory_allocated,
2436 .memory_pressure = &tcp_memory_pressure,
2437 .sysctl_mem = sysctl_tcp_mem,
2438 .sysctl_wmem = sysctl_tcp_wmem,
2439 .sysctl_rmem = sysctl_tcp_rmem,
2440 .max_header = MAX_TCP_HEADER,
2441 .obj_size = sizeof(struct tcp_sock),
2442 .twsk_prot = &tcp_timewait_sock_ops,
2443 .rsk_prot = &tcp_request_sock_ops,
2444 #ifdef CONFIG_COMPAT
2445 .compat_setsockopt = compat_tcp_setsockopt,
2446 .compat_getsockopt = compat_tcp_getsockopt,
2447 #endif
2448 };
2449
2450 void __init tcp_v4_init(struct net_proto_family *ops)
2451 {
2452 if (inet_csk_ctl_sock_create(&tcp_socket, PF_INET, SOCK_RAW,
2453 IPPROTO_TCP) < 0)
2454 panic("Failed to create the TCP control socket.\n");
2455 }
2456
2457 EXPORT_SYMBOL(ipv4_specific);
2458 EXPORT_SYMBOL(tcp_hashinfo);
2459 EXPORT_SYMBOL(tcp_prot);
2460 EXPORT_SYMBOL(tcp_unhash);
2461 EXPORT_SYMBOL(tcp_v4_conn_request);
2462 EXPORT_SYMBOL(tcp_v4_connect);
2463 EXPORT_SYMBOL(tcp_v4_do_rcv);
2464 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2465 EXPORT_SYMBOL(tcp_v4_send_check);
2466 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2467
2468 #ifdef CONFIG_PROC_FS
2469 EXPORT_SYMBOL(tcp_proc_register);
2470 EXPORT_SYMBOL(tcp_proc_unregister);
2471 #endif
2472 EXPORT_SYMBOL(sysctl_local_port_range);
2473 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2474
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