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include/linux/netdevice.h: don't export MAX_HEADER to userspace
[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / net / ipv4 / tcp_ipv4.c
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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
85int sysctl_tcp_tw_reuse __read_mostly;
86int sysctl_tcp_low_latency __read_mostly;
87
88
89#ifdef CONFIG_TCP_MD5SIG
90static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
91 __be32 addr);
92static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
93 __be32 saddr, __be32 daddr,
94 struct tcphdr *th, int protocol,
95 unsigned int tcplen);
96#endif
97
98struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
99 .lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
100 .lhash_users = ATOMIC_INIT(0),
101 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
102};
103
104static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
105{
106 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
107 ip_hdr(skb)->saddr,
108 tcp_hdr(skb)->dest,
109 tcp_hdr(skb)->source);
110}
111
112int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
113{
114 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
115 struct tcp_sock *tp = tcp_sk(sk);
116
117 /* With PAWS, it is safe from the viewpoint
118 of data integrity. Even without PAWS it is safe provided sequence
119 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
120
121 Actually, the idea is close to VJ's one, only timestamp cache is
122 held not per host, but per port pair and TW bucket is used as state
123 holder.
124
125 If TW bucket has been already destroyed we fall back to VJ's scheme
126 and use initial timestamp retrieved from peer table.
127 */
128 if (tcptw->tw_ts_recent_stamp &&
129 (twp == NULL || (sysctl_tcp_tw_reuse &&
130 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
131 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
132 if (tp->write_seq == 0)
133 tp->write_seq = 1;
134 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
135 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
136 sock_hold(sktw);
137 return 1;
138 }
139
140 return 0;
141}
142
143EXPORT_SYMBOL_GPL(tcp_twsk_unique);
144
145/* This will initiate an outgoing connection. */
146int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
147{
148 struct inet_sock *inet = inet_sk(sk);
149 struct tcp_sock *tp = tcp_sk(sk);
150 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
151 struct rtable *rt;
152 __be32 daddr, nexthop;
153 int tmp;
154 int err;
155
156 if (addr_len < sizeof(struct sockaddr_in))
157 return -EINVAL;
158
159 if (usin->sin_family != AF_INET)
160 return -EAFNOSUPPORT;
161
162 nexthop = daddr = usin->sin_addr.s_addr;
163 if (inet->opt && inet->opt->srr) {
164 if (!daddr)
165 return -EINVAL;
166 nexthop = inet->opt->faddr;
167 }
168
169 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
170 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
171 IPPROTO_TCP,
172 inet->sport, usin->sin_port, sk, 1);
173 if (tmp < 0) {
174 if (tmp == -ENETUNREACH)
175 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
176 return tmp;
177 }
178
179 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
180 ip_rt_put(rt);
181 return -ENETUNREACH;
182 }
183
184 if (!inet->opt || !inet->opt->srr)
185 daddr = rt->rt_dst;
186
187 if (!inet->saddr)
188 inet->saddr = rt->rt_src;
189 inet->rcv_saddr = inet->saddr;
190
191 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
192 /* Reset inherited state */
193 tp->rx_opt.ts_recent = 0;
194 tp->rx_opt.ts_recent_stamp = 0;
195 tp->write_seq = 0;
196 }
197
198 if (tcp_death_row.sysctl_tw_recycle &&
199 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
200 struct inet_peer *peer = rt_get_peer(rt);
201 /*
202 * VJ's idea. We save last timestamp seen from
203 * the destination in peer table, when entering state
204 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
205 * when trying new connection.
206 */
207 if (peer != NULL &&
208 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
209 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
210 tp->rx_opt.ts_recent = peer->tcp_ts;
211 }
212 }
213
214 inet->dport = usin->sin_port;
215 inet->daddr = daddr;
216
217 inet_csk(sk)->icsk_ext_hdr_len = 0;
218 if (inet->opt)
219 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
220
221 tp->rx_opt.mss_clamp = 536;
222
223 /* Socket identity is still unknown (sport may be zero).
224 * However we set state to SYN-SENT and not releasing socket
225 * lock select source port, enter ourselves into the hash tables and
226 * complete initialization after this.
227 */
228 tcp_set_state(sk, TCP_SYN_SENT);
229 err = inet_hash_connect(&tcp_death_row, sk);
230 if (err)
231 goto failure;
232
233 err = ip_route_newports(&rt, IPPROTO_TCP,
234 inet->sport, inet->dport, sk);
235 if (err)
236 goto failure;
237
238 /* OK, now commit destination to socket. */
239 sk->sk_gso_type = SKB_GSO_TCPV4;
240 sk_setup_caps(sk, &rt->u.dst);
241
242 if (!tp->write_seq)
243 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
244 inet->daddr,
245 inet->sport,
246 usin->sin_port);
247
248 inet->id = tp->write_seq ^ jiffies;
249
250 err = tcp_connect(sk);
251 rt = NULL;
252 if (err)
253 goto failure;
254
255 return 0;
256
257failure:
258 /*
259 * This unhashes the socket and releases the local port,
260 * if necessary.
261 */
262 tcp_set_state(sk, TCP_CLOSE);
263 ip_rt_put(rt);
264 sk->sk_route_caps = 0;
265 inet->dport = 0;
266 return err;
267}
268
269/*
270 * This routine does path mtu discovery as defined in RFC1191.
271 */
272static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
273{
274 struct dst_entry *dst;
275 struct inet_sock *inet = inet_sk(sk);
276
277 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
278 * send out by Linux are always <576bytes so they should go through
279 * unfragmented).
280 */
281 if (sk->sk_state == TCP_LISTEN)
282 return;
283
284 /* We don't check in the destentry if pmtu discovery is forbidden
285 * on this route. We just assume that no packet_to_big packets
286 * are send back when pmtu discovery is not active.
287 * There is a small race when the user changes this flag in the
288 * route, but I think that's acceptable.
289 */
290 if ((dst = __sk_dst_check(sk, 0)) == NULL)
291 return;
292
293 dst->ops->update_pmtu(dst, mtu);
294
295 /* Something is about to be wrong... Remember soft error
296 * for the case, if this connection will not able to recover.
297 */
298 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
299 sk->sk_err_soft = EMSGSIZE;
300
301 mtu = dst_mtu(dst);
302
303 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
304 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
305 tcp_sync_mss(sk, mtu);
306
307 /* Resend the TCP packet because it's
308 * clear that the old packet has been
309 * dropped. This is the new "fast" path mtu
310 * discovery.
311 */
312 tcp_simple_retransmit(sk);
313 } /* else let the usual retransmit timer handle it */
314}
315
316/*
317 * This routine is called by the ICMP module when it gets some
318 * sort of error condition. If err < 0 then the socket should
319 * be closed and the error returned to the user. If err > 0
320 * it's just the icmp type << 8 | icmp code. After adjustment
321 * header points to the first 8 bytes of the tcp header. We need
322 * to find the appropriate port.
323 *
324 * The locking strategy used here is very "optimistic". When
325 * someone else accesses the socket the ICMP is just dropped
326 * and for some paths there is no check at all.
327 * A more general error queue to queue errors for later handling
328 * is probably better.
329 *
330 */
331
332void tcp_v4_err(struct sk_buff *skb, u32 info)
333{
334 struct iphdr *iph = (struct iphdr *)skb->data;
335 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
336 struct tcp_sock *tp;
337 struct inet_sock *inet;
338 const int type = icmp_hdr(skb)->type;
339 const int code = icmp_hdr(skb)->code;
340 struct sock *sk;
341 __u32 seq;
342 int err;
343
344 if (skb->len < (iph->ihl << 2) + 8) {
345 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
346 return;
347 }
348
349 sk = inet_lookup(dev_net(skb->dev), &tcp_hashinfo, iph->daddr, th->dest,
350 iph->saddr, th->source, inet_iif(skb));
351 if (!sk) {
352 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
353 return;
354 }
355 if (sk->sk_state == TCP_TIME_WAIT) {
356 inet_twsk_put(inet_twsk(sk));
357 return;
358 }
359
360 bh_lock_sock(sk);
361 /* If too many ICMPs get dropped on busy
362 * servers this needs to be solved differently.
363 */
364 if (sock_owned_by_user(sk))
365 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
366
367 if (sk->sk_state == TCP_CLOSE)
368 goto out;
369
370 tp = tcp_sk(sk);
371 seq = ntohl(th->seq);
372 if (sk->sk_state != TCP_LISTEN &&
373 !between(seq, tp->snd_una, tp->snd_nxt)) {
374 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
375 goto out;
376 }
377
378 switch (type) {
379 case ICMP_SOURCE_QUENCH:
380 /* Just silently ignore these. */
381 goto out;
382 case ICMP_PARAMETERPROB:
383 err = EPROTO;
384 break;
385 case ICMP_DEST_UNREACH:
386 if (code > NR_ICMP_UNREACH)
387 goto out;
388
389 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
390 if (!sock_owned_by_user(sk))
391 do_pmtu_discovery(sk, iph, info);
392 goto out;
393 }
394
395 err = icmp_err_convert[code].errno;
396 break;
397 case ICMP_TIME_EXCEEDED:
398 err = EHOSTUNREACH;
399 break;
400 default:
401 goto out;
402 }
403
404 switch (sk->sk_state) {
405 struct request_sock *req, **prev;
406 case TCP_LISTEN:
407 if (sock_owned_by_user(sk))
408 goto out;
409
410 req = inet_csk_search_req(sk, &prev, th->dest,
411 iph->daddr, iph->saddr);
412 if (!req)
413 goto out;
414
415 /* ICMPs are not backlogged, hence we cannot get
416 an established socket here.
417 */
418 BUG_TRAP(!req->sk);
419
420 if (seq != tcp_rsk(req)->snt_isn) {
421 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
422 goto out;
423 }
424
425 /*
426 * Still in SYN_RECV, just remove it silently.
427 * There is no good way to pass the error to the newly
428 * created socket, and POSIX does not want network
429 * errors returned from accept().
430 */
431 inet_csk_reqsk_queue_drop(sk, req, prev);
432 goto out;
433
434 case TCP_SYN_SENT:
435 case TCP_SYN_RECV: /* Cannot happen.
436 It can f.e. if SYNs crossed.
437 */
438 if (!sock_owned_by_user(sk)) {
439 sk->sk_err = err;
440
441 sk->sk_error_report(sk);
442
443 tcp_done(sk);
444 } else {
445 sk->sk_err_soft = err;
446 }
447 goto out;
448 }
449
450 /* If we've already connected we will keep trying
451 * until we time out, or the user gives up.
452 *
453 * rfc1122 4.2.3.9 allows to consider as hard errors
454 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
455 * but it is obsoleted by pmtu discovery).
456 *
457 * Note, that in modern internet, where routing is unreliable
458 * and in each dark corner broken firewalls sit, sending random
459 * errors ordered by their masters even this two messages finally lose
460 * their original sense (even Linux sends invalid PORT_UNREACHs)
461 *
462 * Now we are in compliance with RFCs.
463 * --ANK (980905)
464 */
465
466 inet = inet_sk(sk);
467 if (!sock_owned_by_user(sk) && inet->recverr) {
468 sk->sk_err = err;
469 sk->sk_error_report(sk);
470 } else { /* Only an error on timeout */
471 sk->sk_err_soft = err;
472 }
473
474out:
475 bh_unlock_sock(sk);
476 sock_put(sk);
477}
478
479/* This routine computes an IPv4 TCP checksum. */
480void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
481{
482 struct inet_sock *inet = inet_sk(sk);
483 struct tcphdr *th = tcp_hdr(skb);
484
485 if (skb->ip_summed == CHECKSUM_PARTIAL) {
486 th->check = ~tcp_v4_check(len, inet->saddr,
487 inet->daddr, 0);
488 skb->csum_start = skb_transport_header(skb) - skb->head;
489 skb->csum_offset = offsetof(struct tcphdr, check);
490 } else {
491 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
492 csum_partial((char *)th,
493 th->doff << 2,
494 skb->csum));
495 }
496}
497
498int tcp_v4_gso_send_check(struct sk_buff *skb)
499{
500 const struct iphdr *iph;
501 struct tcphdr *th;
502
503 if (!pskb_may_pull(skb, sizeof(*th)))
504 return -EINVAL;
505
506 iph = ip_hdr(skb);
507 th = tcp_hdr(skb);
508
509 th->check = 0;
510 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 skb->ip_summed = CHECKSUM_PARTIAL;
514 return 0;
515}
516
517/*
518 * This routine will send an RST to the other tcp.
519 *
520 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
521 * for reset.
522 * Answer: if a packet caused RST, it is not for a socket
523 * existing in our system, if it is matched to a socket,
524 * it is just duplicate segment or bug in other side's TCP.
525 * So that we build reply only basing on parameters
526 * arrived with segment.
527 * Exception: precedence violation. We do not implement it in any case.
528 */
529
530static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
531{
532 struct tcphdr *th = tcp_hdr(skb);
533 struct {
534 struct tcphdr th;
535#ifdef CONFIG_TCP_MD5SIG
536 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
537#endif
538 } rep;
539 struct ip_reply_arg arg;
540#ifdef CONFIG_TCP_MD5SIG
541 struct tcp_md5sig_key *key;
542#endif
543
544 /* Never send a reset in response to a reset. */
545 if (th->rst)
546 return;
547
548 if (skb->rtable->rt_type != RTN_LOCAL)
549 return;
550
551 /* Swap the send and the receive. */
552 memset(&rep, 0, sizeof(rep));
553 rep.th.dest = th->source;
554 rep.th.source = th->dest;
555 rep.th.doff = sizeof(struct tcphdr) / 4;
556 rep.th.rst = 1;
557
558 if (th->ack) {
559 rep.th.seq = th->ack_seq;
560 } else {
561 rep.th.ack = 1;
562 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
563 skb->len - (th->doff << 2));
564 }
565
566 memset(&arg, 0, sizeof(arg));
567 arg.iov[0].iov_base = (unsigned char *)&rep;
568 arg.iov[0].iov_len = sizeof(rep.th);
569
570#ifdef CONFIG_TCP_MD5SIG
571 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
572 if (key) {
573 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
574 (TCPOPT_NOP << 16) |
575 (TCPOPT_MD5SIG << 8) |
576 TCPOLEN_MD5SIG);
577 /* Update length and the length the header thinks exists */
578 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
579 rep.th.doff = arg.iov[0].iov_len / 4;
580
581 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
582 key,
583 ip_hdr(skb)->daddr,
584 ip_hdr(skb)->saddr,
585 &rep.th, IPPROTO_TCP,
586 arg.iov[0].iov_len);
587 }
588#endif
589 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
590 ip_hdr(skb)->saddr, /* XXX */
591 sizeof(struct tcphdr), IPPROTO_TCP, 0);
592 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
593
594 ip_send_reply(dev_net(skb->dst->dev)->ipv4.tcp_sock, skb,
595 &arg, arg.iov[0].iov_len);
596
597 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
598 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
599}
600
601/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
602 outside socket context is ugly, certainly. What can I do?
603 */
604
605static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
606 struct sk_buff *skb, u32 seq, u32 ack,
607 u32 win, u32 ts)
608{
609 struct tcphdr *th = tcp_hdr(skb);
610 struct {
611 struct tcphdr th;
612 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
613#ifdef CONFIG_TCP_MD5SIG
614 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
615#endif
616 ];
617 } rep;
618 struct ip_reply_arg arg;
619#ifdef CONFIG_TCP_MD5SIG
620 struct tcp_md5sig_key *key;
621 struct tcp_md5sig_key tw_key;
622#endif
623
624 memset(&rep.th, 0, sizeof(struct tcphdr));
625 memset(&arg, 0, sizeof(arg));
626
627 arg.iov[0].iov_base = (unsigned char *)&rep;
628 arg.iov[0].iov_len = sizeof(rep.th);
629 if (ts) {
630 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
631 (TCPOPT_TIMESTAMP << 8) |
632 TCPOLEN_TIMESTAMP);
633 rep.opt[1] = htonl(tcp_time_stamp);
634 rep.opt[2] = htonl(ts);
635 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
636 }
637
638 /* Swap the send and the receive. */
639 rep.th.dest = th->source;
640 rep.th.source = th->dest;
641 rep.th.doff = arg.iov[0].iov_len / 4;
642 rep.th.seq = htonl(seq);
643 rep.th.ack_seq = htonl(ack);
644 rep.th.ack = 1;
645 rep.th.window = htons(win);
646
647#ifdef CONFIG_TCP_MD5SIG
648 /*
649 * The SKB holds an imcoming packet, but may not have a valid ->sk
650 * pointer. This is especially the case when we're dealing with a
651 * TIME_WAIT ack, because the sk structure is long gone, and only
652 * the tcp_timewait_sock remains. So the md5 key is stashed in that
653 * structure, and we use it in preference. I believe that (twsk ||
654 * skb->sk) holds true, but we program defensively.
655 */
656 if (!twsk && skb->sk) {
657 key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
658 } else if (twsk && twsk->tw_md5_keylen) {
659 tw_key.key = twsk->tw_md5_key;
660 tw_key.keylen = twsk->tw_md5_keylen;
661 key = &tw_key;
662 } else
663 key = NULL;
664
665 if (key) {
666 int offset = (ts) ? 3 : 0;
667
668 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
669 (TCPOPT_NOP << 16) |
670 (TCPOPT_MD5SIG << 8) |
671 TCPOLEN_MD5SIG);
672 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
673 rep.th.doff = arg.iov[0].iov_len/4;
674
675 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
676 key,
677 ip_hdr(skb)->daddr,
678 ip_hdr(skb)->saddr,
679 &rep.th, IPPROTO_TCP,
680 arg.iov[0].iov_len);
681 }
682#endif
683 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
684 ip_hdr(skb)->saddr, /* XXX */
685 arg.iov[0].iov_len, IPPROTO_TCP, 0);
686 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
687 if (twsk)
688 arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
689
690 ip_send_reply(dev_net(skb->dev)->ipv4.tcp_sock, skb,
691 &arg, arg.iov[0].iov_len);
692
693 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
694}
695
696static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
697{
698 struct inet_timewait_sock *tw = inet_twsk(sk);
699 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
700
701 tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
702 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
703 tcptw->tw_ts_recent);
704
705 inet_twsk_put(tw);
706}
707
708static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
709 struct request_sock *req)
710{
711 tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
712 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
713 req->ts_recent);
714}
715
716/*
717 * Send a SYN-ACK after having received a SYN.
718 * This still operates on a request_sock only, not on a big
719 * socket.
720 */
721static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
722 struct dst_entry *dst)
723{
724 const struct inet_request_sock *ireq = inet_rsk(req);
725 int err = -1;
726 struct sk_buff * skb;
727
728 /* First, grab a route. */
729 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
730 return -1;
731
732 skb = tcp_make_synack(sk, dst, req);
733
734 if (skb) {
735 struct tcphdr *th = tcp_hdr(skb);
736
737 th->check = tcp_v4_check(skb->len,
738 ireq->loc_addr,
739 ireq->rmt_addr,
740 csum_partial((char *)th, skb->len,
741 skb->csum));
742
743 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
744 ireq->rmt_addr,
745 ireq->opt);
746 err = net_xmit_eval(err);
747 }
748
749 dst_release(dst);
750 return err;
751}
752
753static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
754{
755 return __tcp_v4_send_synack(sk, req, NULL);
756}
757
758/*
759 * IPv4 request_sock destructor.
760 */
761static void tcp_v4_reqsk_destructor(struct request_sock *req)
762{
763 kfree(inet_rsk(req)->opt);
764}
765
766#ifdef CONFIG_SYN_COOKIES
767static void syn_flood_warning(struct sk_buff *skb)
768{
769 static unsigned long warntime;
770
771 if (time_after(jiffies, (warntime + HZ * 60))) {
772 warntime = jiffies;
773 printk(KERN_INFO
774 "possible SYN flooding on port %d. Sending cookies.\n",
775 ntohs(tcp_hdr(skb)->dest));
776 }
777}
778#endif
779
780/*
781 * Save and compile IPv4 options into the request_sock if needed.
782 */
783static struct ip_options *tcp_v4_save_options(struct sock *sk,
784 struct sk_buff *skb)
785{
786 struct ip_options *opt = &(IPCB(skb)->opt);
787 struct ip_options *dopt = NULL;
788
789 if (opt && opt->optlen) {
790 int opt_size = optlength(opt);
791 dopt = kmalloc(opt_size, GFP_ATOMIC);
792 if (dopt) {
793 if (ip_options_echo(dopt, skb)) {
794 kfree(dopt);
795 dopt = NULL;
796 }
797 }
798 }
799 return dopt;
800}
801
802#ifdef CONFIG_TCP_MD5SIG
803/*
804 * RFC2385 MD5 checksumming requires a mapping of
805 * IP address->MD5 Key.
806 * We need to maintain these in the sk structure.
807 */
808
809/* Find the Key structure for an address. */
810static struct tcp_md5sig_key *
811 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
812{
813 struct tcp_sock *tp = tcp_sk(sk);
814 int i;
815
816 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
817 return NULL;
818 for (i = 0; i < tp->md5sig_info->entries4; i++) {
819 if (tp->md5sig_info->keys4[i].addr == addr)
820 return &tp->md5sig_info->keys4[i].base;
821 }
822 return NULL;
823}
824
825struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
826 struct sock *addr_sk)
827{
828 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
829}
830
831EXPORT_SYMBOL(tcp_v4_md5_lookup);
832
833static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
834 struct request_sock *req)
835{
836 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
837}
838
839/* This can be called on a newly created socket, from other files */
840int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
841 u8 *newkey, u8 newkeylen)
842{
843 /* Add Key to the list */
844 struct tcp_md5sig_key *key;
845 struct tcp_sock *tp = tcp_sk(sk);
846 struct tcp4_md5sig_key *keys;
847
848 key = tcp_v4_md5_do_lookup(sk, addr);
849 if (key) {
850 /* Pre-existing entry - just update that one. */
851 kfree(key->key);
852 key->key = newkey;
853 key->keylen = newkeylen;
854 } else {
855 struct tcp_md5sig_info *md5sig;
856
857 if (!tp->md5sig_info) {
858 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
859 GFP_ATOMIC);
860 if (!tp->md5sig_info) {
861 kfree(newkey);
862 return -ENOMEM;
863 }
864 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
865 }
866 if (tcp_alloc_md5sig_pool() == NULL) {
867 kfree(newkey);
868 return -ENOMEM;
869 }
870 md5sig = tp->md5sig_info;
871
872 if (md5sig->alloced4 == md5sig->entries4) {
873 keys = kmalloc((sizeof(*keys) *
874 (md5sig->entries4 + 1)), GFP_ATOMIC);
875 if (!keys) {
876 kfree(newkey);
877 tcp_free_md5sig_pool();
878 return -ENOMEM;
879 }
880
881 if (md5sig->entries4)
882 memcpy(keys, md5sig->keys4,
883 sizeof(*keys) * md5sig->entries4);
884
885 /* Free old key list, and reference new one */
886 kfree(md5sig->keys4);
887 md5sig->keys4 = keys;
888 md5sig->alloced4++;
889 }
890 md5sig->entries4++;
891 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
892 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
893 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
894 }
895 return 0;
896}
897
898EXPORT_SYMBOL(tcp_v4_md5_do_add);
899
900static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
901 u8 *newkey, u8 newkeylen)
902{
903 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
904 newkey, newkeylen);
905}
906
907int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
908{
909 struct tcp_sock *tp = tcp_sk(sk);
910 int i;
911
912 for (i = 0; i < tp->md5sig_info->entries4; i++) {
913 if (tp->md5sig_info->keys4[i].addr == addr) {
914 /* Free the key */
915 kfree(tp->md5sig_info->keys4[i].base.key);
916 tp->md5sig_info->entries4--;
917
918 if (tp->md5sig_info->entries4 == 0) {
919 kfree(tp->md5sig_info->keys4);
920 tp->md5sig_info->keys4 = NULL;
921 tp->md5sig_info->alloced4 = 0;
922 } else if (tp->md5sig_info->entries4 != i) {
923 /* Need to do some manipulation */
924 memmove(&tp->md5sig_info->keys4[i],
925 &tp->md5sig_info->keys4[i+1],
926 (tp->md5sig_info->entries4 - i) *
927 sizeof(struct tcp4_md5sig_key));
928 }
929 tcp_free_md5sig_pool();
930 return 0;
931 }
932 }
933 return -ENOENT;
934}
935
936EXPORT_SYMBOL(tcp_v4_md5_do_del);
937
938static void tcp_v4_clear_md5_list(struct sock *sk)
939{
940 struct tcp_sock *tp = tcp_sk(sk);
941
942 /* Free each key, then the set of key keys,
943 * the crypto element, and then decrement our
944 * hold on the last resort crypto.
945 */
946 if (tp->md5sig_info->entries4) {
947 int i;
948 for (i = 0; i < tp->md5sig_info->entries4; i++)
949 kfree(tp->md5sig_info->keys4[i].base.key);
950 tp->md5sig_info->entries4 = 0;
951 tcp_free_md5sig_pool();
952 }
953 if (tp->md5sig_info->keys4) {
954 kfree(tp->md5sig_info->keys4);
955 tp->md5sig_info->keys4 = NULL;
956 tp->md5sig_info->alloced4 = 0;
957 }
958}
959
960static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
961 int optlen)
962{
963 struct tcp_md5sig cmd;
964 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
965 u8 *newkey;
966
967 if (optlen < sizeof(cmd))
968 return -EINVAL;
969
970 if (copy_from_user(&cmd, optval, sizeof(cmd)))
971 return -EFAULT;
972
973 if (sin->sin_family != AF_INET)
974 return -EINVAL;
975
976 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
977 if (!tcp_sk(sk)->md5sig_info)
978 return -ENOENT;
979 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
980 }
981
982 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
983 return -EINVAL;
984
985 if (!tcp_sk(sk)->md5sig_info) {
986 struct tcp_sock *tp = tcp_sk(sk);
987 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
988
989 if (!p)
990 return -EINVAL;
991
992 tp->md5sig_info = p;
993 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
994 }
995
996 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
997 if (!newkey)
998 return -ENOMEM;
999 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1000 newkey, cmd.tcpm_keylen);
1001}
1002
1003static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1004 __be32 saddr, __be32 daddr,
1005 struct tcphdr *th, int protocol,
1006 unsigned int tcplen)
1007{
1008 struct scatterlist sg[4];
1009 __u16 data_len;
1010 int block = 0;
1011 __sum16 old_checksum;
1012 struct tcp_md5sig_pool *hp;
1013 struct tcp4_pseudohdr *bp;
1014 struct hash_desc *desc;
1015 int err;
1016 unsigned int nbytes = 0;
1017
1018 /*
1019 * Okay, so RFC2385 is turned on for this connection,
1020 * so we need to generate the MD5 hash for the packet now.
1021 */
1022
1023 hp = tcp_get_md5sig_pool();
1024 if (!hp)
1025 goto clear_hash_noput;
1026
1027 bp = &hp->md5_blk.ip4;
1028 desc = &hp->md5_desc;
1029
1030 /*
1031 * 1. the TCP pseudo-header (in the order: source IP address,
1032 * destination IP address, zero-padded protocol number, and
1033 * segment length)
1034 */
1035 bp->saddr = saddr;
1036 bp->daddr = daddr;
1037 bp->pad = 0;
1038 bp->protocol = protocol;
1039 bp->len = htons(tcplen);
1040
1041 sg_init_table(sg, 4);
1042
1043 sg_set_buf(&sg[block++], bp, sizeof(*bp));
1044 nbytes += sizeof(*bp);
1045
1046 /* 2. the TCP header, excluding options, and assuming a
1047 * checksum of zero/
1048 */
1049 old_checksum = th->check;
1050 th->check = 0;
1051 sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
1052 nbytes += sizeof(struct tcphdr);
1053
1054 /* 3. the TCP segment data (if any) */
1055 data_len = tcplen - (th->doff << 2);
1056 if (data_len > 0) {
1057 unsigned char *data = (unsigned char *)th + (th->doff << 2);
1058 sg_set_buf(&sg[block++], data, data_len);
1059 nbytes += data_len;
1060 }
1061
1062 /* 4. an independently-specified key or password, known to both
1063 * TCPs and presumably connection-specific
1064 */
1065 sg_set_buf(&sg[block++], key->key, key->keylen);
1066 nbytes += key->keylen;
1067
1068 sg_mark_end(&sg[block - 1]);
1069
1070 /* Now store the Hash into the packet */
1071 err = crypto_hash_init(desc);
1072 if (err)
1073 goto clear_hash;
1074 err = crypto_hash_update(desc, sg, nbytes);
1075 if (err)
1076 goto clear_hash;
1077 err = crypto_hash_final(desc, md5_hash);
1078 if (err)
1079 goto clear_hash;
1080
1081 /* Reset header, and free up the crypto */
1082 tcp_put_md5sig_pool();
1083 th->check = old_checksum;
1084
1085out:
1086 return 0;
1087clear_hash:
1088 tcp_put_md5sig_pool();
1089clear_hash_noput:
1090 memset(md5_hash, 0, 16);
1091 goto out;
1092}
1093
1094int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1095 struct sock *sk,
1096 struct dst_entry *dst,
1097 struct request_sock *req,
1098 struct tcphdr *th, int protocol,
1099 unsigned int tcplen)
1100{
1101 __be32 saddr, daddr;
1102
1103 if (sk) {
1104 saddr = inet_sk(sk)->saddr;
1105 daddr = inet_sk(sk)->daddr;
1106 } else {
1107 struct rtable *rt = (struct rtable *)dst;
1108 BUG_ON(!rt);
1109 saddr = rt->rt_src;
1110 daddr = rt->rt_dst;
1111 }
1112 return tcp_v4_do_calc_md5_hash(md5_hash, key,
1113 saddr, daddr,
1114 th, protocol, tcplen);
1115}
1116
1117EXPORT_SYMBOL(tcp_v4_calc_md5_hash);
1118
1119static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1120{
1121 /*
1122 * This gets called for each TCP segment that arrives
1123 * so we want to be efficient.
1124 * We have 3 drop cases:
1125 * o No MD5 hash and one expected.
1126 * o MD5 hash and we're not expecting one.
1127 * o MD5 hash and its wrong.
1128 */
1129 __u8 *hash_location = NULL;
1130 struct tcp_md5sig_key *hash_expected;
1131 const struct iphdr *iph = ip_hdr(skb);
1132 struct tcphdr *th = tcp_hdr(skb);
1133 int length = (th->doff << 2) - sizeof(struct tcphdr);
1134 int genhash;
1135 unsigned char *ptr;
1136 unsigned char newhash[16];
1137
1138 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1139
1140 /*
1141 * If the TCP option length is less than the TCP_MD5SIG
1142 * option length, then we can shortcut
1143 */
1144 if (length < TCPOLEN_MD5SIG) {
1145 if (hash_expected)
1146 return 1;
1147 else
1148 return 0;
1149 }
1150
1151 /* Okay, we can't shortcut - we have to grub through the options */
1152 ptr = (unsigned char *)(th + 1);
1153 while (length > 0) {
1154 int opcode = *ptr++;
1155 int opsize;
1156
1157 switch (opcode) {
1158 case TCPOPT_EOL:
1159 goto done_opts;
1160 case TCPOPT_NOP:
1161 length--;
1162 continue;
1163 default:
1164 opsize = *ptr++;
1165 if (opsize < 2)
1166 goto done_opts;
1167 if (opsize > length)
1168 goto done_opts;
1169
1170 if (opcode == TCPOPT_MD5SIG) {
1171 hash_location = ptr;
1172 goto done_opts;
1173 }
1174 }
1175 ptr += opsize-2;
1176 length -= opsize;
1177 }
1178done_opts:
1179 /* We've parsed the options - do we have a hash? */
1180 if (!hash_expected && !hash_location)
1181 return 0;
1182
1183 if (hash_expected && !hash_location) {
1184 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
1185 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1186 NIPQUAD(iph->saddr), ntohs(th->source),
1187 NIPQUAD(iph->daddr), ntohs(th->dest));
1188 return 1;
1189 }
1190
1191 if (!hash_expected && hash_location) {
1192 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
1193 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1194 NIPQUAD(iph->saddr), ntohs(th->source),
1195 NIPQUAD(iph->daddr), ntohs(th->dest));
1196 return 1;
1197 }
1198
1199 /* Okay, so this is hash_expected and hash_location -
1200 * so we need to calculate the checksum.
1201 */
1202 genhash = tcp_v4_do_calc_md5_hash(newhash,
1203 hash_expected,
1204 iph->saddr, iph->daddr,
1205 th, sk->sk_protocol,
1206 skb->len);
1207
1208 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1209 if (net_ratelimit()) {
1210 printk(KERN_INFO "MD5 Hash failed for "
1211 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
1212 NIPQUAD(iph->saddr), ntohs(th->source),
1213 NIPQUAD(iph->daddr), ntohs(th->dest),
1214 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1215 }
1216 return 1;
1217 }
1218 return 0;
1219}
1220
1221#endif
1222
1223struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1224 .family = PF_INET,
1225 .obj_size = sizeof(struct tcp_request_sock),
1226 .rtx_syn_ack = tcp_v4_send_synack,
1227 .send_ack = tcp_v4_reqsk_send_ack,
1228 .destructor = tcp_v4_reqsk_destructor,
1229 .send_reset = tcp_v4_send_reset,
1230};
1231
1232#ifdef CONFIG_TCP_MD5SIG
1233static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1234 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1235};
1236#endif
1237
1238static struct timewait_sock_ops tcp_timewait_sock_ops = {
1239 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1240 .twsk_unique = tcp_twsk_unique,
1241 .twsk_destructor= tcp_twsk_destructor,
1242};
1243
1244int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1245{
1246 struct inet_request_sock *ireq;
1247 struct tcp_options_received tmp_opt;
1248 struct request_sock *req;
1249 __be32 saddr = ip_hdr(skb)->saddr;
1250 __be32 daddr = ip_hdr(skb)->daddr;
1251 __u32 isn = TCP_SKB_CB(skb)->when;
1252 struct dst_entry *dst = NULL;
1253#ifdef CONFIG_SYN_COOKIES
1254 int want_cookie = 0;
1255#else
1256#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1257#endif
1258
1259 /* Never answer to SYNs send to broadcast or multicast */
1260 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1261 goto drop;
1262
1263 /* TW buckets are converted to open requests without
1264 * limitations, they conserve resources and peer is
1265 * evidently real one.
1266 */
1267 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1268#ifdef CONFIG_SYN_COOKIES
1269 if (sysctl_tcp_syncookies) {
1270 want_cookie = 1;
1271 } else
1272#endif
1273 goto drop;
1274 }
1275
1276 /* Accept backlog is full. If we have already queued enough
1277 * of warm entries in syn queue, drop request. It is better than
1278 * clogging syn queue with openreqs with exponentially increasing
1279 * timeout.
1280 */
1281 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1282 goto drop;
1283
1284 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1285 if (!req)
1286 goto drop;
1287
1288#ifdef CONFIG_TCP_MD5SIG
1289 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1290#endif
1291
1292 tcp_clear_options(&tmp_opt);
1293 tmp_opt.mss_clamp = 536;
1294 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1295
1296 tcp_parse_options(skb, &tmp_opt, 0);
1297
1298 if (want_cookie && !tmp_opt.saw_tstamp)
1299 tcp_clear_options(&tmp_opt);
1300
1301 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1302 /* Some OSes (unknown ones, but I see them on web server, which
1303 * contains information interesting only for windows'
1304 * users) do not send their stamp in SYN. It is easy case.
1305 * We simply do not advertise TS support.
1306 */
1307 tmp_opt.saw_tstamp = 0;
1308 tmp_opt.tstamp_ok = 0;
1309 }
1310 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1311
1312 tcp_openreq_init(req, &tmp_opt, skb);
1313
1314 if (security_inet_conn_request(sk, skb, req))
1315 goto drop_and_free;
1316
1317 ireq = inet_rsk(req);
1318 ireq->loc_addr = daddr;
1319 ireq->rmt_addr = saddr;
1320 ireq->opt = tcp_v4_save_options(sk, skb);
1321 if (!want_cookie)
1322 TCP_ECN_create_request(req, tcp_hdr(skb));
1323
1324 if (want_cookie) {
1325#ifdef CONFIG_SYN_COOKIES
1326 syn_flood_warning(skb);
1327 req->cookie_ts = tmp_opt.tstamp_ok;
1328#endif
1329 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1330 } else if (!isn) {
1331 struct inet_peer *peer = NULL;
1332
1333 /* VJ's idea. We save last timestamp seen
1334 * from the destination in peer table, when entering
1335 * state TIME-WAIT, and check against it before
1336 * accepting new connection request.
1337 *
1338 * If "isn" is not zero, this request hit alive
1339 * timewait bucket, so that all the necessary checks
1340 * are made in the function processing timewait state.
1341 */
1342 if (tmp_opt.saw_tstamp &&
1343 tcp_death_row.sysctl_tw_recycle &&
1344 (dst = inet_csk_route_req(sk, req)) != NULL &&
1345 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1346 peer->v4daddr == saddr) {
1347 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1348 (s32)(peer->tcp_ts - req->ts_recent) >
1349 TCP_PAWS_WINDOW) {
1350 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1351 goto drop_and_release;
1352 }
1353 }
1354 /* Kill the following clause, if you dislike this way. */
1355 else if (!sysctl_tcp_syncookies &&
1356 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1357 (sysctl_max_syn_backlog >> 2)) &&
1358 (!peer || !peer->tcp_ts_stamp) &&
1359 (!dst || !dst_metric(dst, RTAX_RTT))) {
1360 /* Without syncookies last quarter of
1361 * backlog is filled with destinations,
1362 * proven to be alive.
1363 * It means that we continue to communicate
1364 * to destinations, already remembered
1365 * to the moment of synflood.
1366 */
1367 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
1368 "request from " NIPQUAD_FMT "/%u\n",
1369 NIPQUAD(saddr),
1370 ntohs(tcp_hdr(skb)->source));
1371 goto drop_and_release;
1372 }
1373
1374 isn = tcp_v4_init_sequence(skb);
1375 }
1376 tcp_rsk(req)->snt_isn = isn;
1377
1378 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1379 goto drop_and_free;
1380
1381 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1382 return 0;
1383
1384drop_and_release:
1385 dst_release(dst);
1386drop_and_free:
1387 reqsk_free(req);
1388drop:
1389 return 0;
1390}
1391
1392
1393/*
1394 * The three way handshake has completed - we got a valid synack -
1395 * now create the new socket.
1396 */
1397struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1398 struct request_sock *req,
1399 struct dst_entry *dst)
1400{
1401 struct inet_request_sock *ireq;
1402 struct inet_sock *newinet;
1403 struct tcp_sock *newtp;
1404 struct sock *newsk;
1405#ifdef CONFIG_TCP_MD5SIG
1406 struct tcp_md5sig_key *key;
1407#endif
1408
1409 if (sk_acceptq_is_full(sk))
1410 goto exit_overflow;
1411
1412 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1413 goto exit;
1414
1415 newsk = tcp_create_openreq_child(sk, req, skb);
1416 if (!newsk)
1417 goto exit;
1418
1419 newsk->sk_gso_type = SKB_GSO_TCPV4;
1420 sk_setup_caps(newsk, dst);
1421
1422 newtp = tcp_sk(newsk);
1423 newinet = inet_sk(newsk);
1424 ireq = inet_rsk(req);
1425 newinet->daddr = ireq->rmt_addr;
1426 newinet->rcv_saddr = ireq->loc_addr;
1427 newinet->saddr = ireq->loc_addr;
1428 newinet->opt = ireq->opt;
1429 ireq->opt = NULL;
1430 newinet->mc_index = inet_iif(skb);
1431 newinet->mc_ttl = ip_hdr(skb)->ttl;
1432 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1433 if (newinet->opt)
1434 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1435 newinet->id = newtp->write_seq ^ jiffies;
1436
1437 tcp_mtup_init(newsk);
1438 tcp_sync_mss(newsk, dst_mtu(dst));
1439 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1440 tcp_initialize_rcv_mss(newsk);
1441
1442#ifdef CONFIG_TCP_MD5SIG
1443 /* Copy over the MD5 key from the original socket */
1444 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1445 /*
1446 * We're using one, so create a matching key
1447 * on the newsk structure. If we fail to get
1448 * memory, then we end up not copying the key
1449 * across. Shucks.
1450 */
1451 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1452 if (newkey != NULL)
1453 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1454 newkey, key->keylen);
1455 }
1456#endif
1457
1458 __inet_hash_nolisten(newsk);
1459 __inet_inherit_port(sk, newsk);
1460
1461 return newsk;
1462
1463exit_overflow:
1464 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1465exit:
1466 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1467 dst_release(dst);
1468 return NULL;
1469}
1470
1471static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1472{
1473 struct tcphdr *th = tcp_hdr(skb);
1474 const struct iphdr *iph = ip_hdr(skb);
1475 struct sock *nsk;
1476 struct request_sock **prev;
1477 /* Find possible connection requests. */
1478 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1479 iph->saddr, iph->daddr);
1480 if (req)
1481 return tcp_check_req(sk, skb, req, prev);
1482
1483 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1484 th->source, iph->daddr, th->dest, inet_iif(skb));
1485
1486 if (nsk) {
1487 if (nsk->sk_state != TCP_TIME_WAIT) {
1488 bh_lock_sock(nsk);
1489 return nsk;
1490 }
1491 inet_twsk_put(inet_twsk(nsk));
1492 return NULL;
1493 }
1494
1495#ifdef CONFIG_SYN_COOKIES
1496 if (!th->rst && !th->syn && th->ack)
1497 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1498#endif
1499 return sk;
1500}
1501
1502static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1503{
1504 const struct iphdr *iph = ip_hdr(skb);
1505
1506 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1507 if (!tcp_v4_check(skb->len, iph->saddr,
1508 iph->daddr, skb->csum)) {
1509 skb->ip_summed = CHECKSUM_UNNECESSARY;
1510 return 0;
1511 }
1512 }
1513
1514 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1515 skb->len, IPPROTO_TCP, 0);
1516
1517 if (skb->len <= 76) {
1518 return __skb_checksum_complete(skb);
1519 }
1520 return 0;
1521}
1522
1523
1524/* The socket must have it's spinlock held when we get
1525 * here.
1526 *
1527 * We have a potential double-lock case here, so even when
1528 * doing backlog processing we use the BH locking scheme.
1529 * This is because we cannot sleep with the original spinlock
1530 * held.
1531 */
1532int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1533{
1534 struct sock *rsk;
1535#ifdef CONFIG_TCP_MD5SIG
1536 /*
1537 * We really want to reject the packet as early as possible
1538 * if:
1539 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1540 * o There is an MD5 option and we're not expecting one
1541 */
1542 if (tcp_v4_inbound_md5_hash(sk, skb))
1543 goto discard;
1544#endif
1545
1546 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1547 TCP_CHECK_TIMER(sk);
1548 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1549 rsk = sk;
1550 goto reset;
1551 }
1552 TCP_CHECK_TIMER(sk);
1553 return 0;
1554 }
1555
1556 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1557 goto csum_err;
1558
1559 if (sk->sk_state == TCP_LISTEN) {
1560 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1561 if (!nsk)
1562 goto discard;
1563
1564 if (nsk != sk) {
1565 if (tcp_child_process(sk, nsk, skb)) {
1566 rsk = nsk;
1567 goto reset;
1568 }
1569 return 0;
1570 }
1571 }
1572
1573 TCP_CHECK_TIMER(sk);
1574 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1575 rsk = sk;
1576 goto reset;
1577 }
1578 TCP_CHECK_TIMER(sk);
1579 return 0;
1580
1581reset:
1582 tcp_v4_send_reset(rsk, skb);
1583discard:
1584 kfree_skb(skb);
1585 /* Be careful here. If this function gets more complicated and
1586 * gcc suffers from register pressure on the x86, sk (in %ebx)
1587 * might be destroyed here. This current version compiles correctly,
1588 * but you have been warned.
1589 */
1590 return 0;
1591
1592csum_err:
1593 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1594 goto discard;
1595}
1596
1597/*
1598 * From tcp_input.c
1599 */
1600
1601int tcp_v4_rcv(struct sk_buff *skb)
1602{
1603 const struct iphdr *iph;
1604 struct tcphdr *th;
1605 struct sock *sk;
1606 int ret;
1607
1608 if (skb->pkt_type != PACKET_HOST)
1609 goto discard_it;
1610
1611 /* Count it even if it's bad */
1612 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1613
1614 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1615 goto discard_it;
1616
1617 th = tcp_hdr(skb);
1618
1619 if (th->doff < sizeof(struct tcphdr) / 4)
1620 goto bad_packet;
1621 if (!pskb_may_pull(skb, th->doff * 4))
1622 goto discard_it;
1623
1624 /* An explanation is required here, I think.
1625 * Packet length and doff are validated by header prediction,
1626 * provided case of th->doff==0 is eliminated.
1627 * So, we defer the checks. */
1628 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1629 goto bad_packet;
1630
1631 th = tcp_hdr(skb);
1632 iph = ip_hdr(skb);
1633 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1634 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1635 skb->len - th->doff * 4);
1636 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1637 TCP_SKB_CB(skb)->when = 0;
1638 TCP_SKB_CB(skb)->flags = iph->tos;
1639 TCP_SKB_CB(skb)->sacked = 0;
1640
1641 sk = __inet_lookup(dev_net(skb->dev), &tcp_hashinfo, iph->saddr,
1642 th->source, iph->daddr, th->dest, inet_iif(skb));
1643 if (!sk)
1644 goto no_tcp_socket;
1645
1646process:
1647 if (sk->sk_state == TCP_TIME_WAIT)
1648 goto do_time_wait;
1649
1650 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1651 goto discard_and_relse;
1652 nf_reset(skb);
1653
1654 if (sk_filter(sk, skb))
1655 goto discard_and_relse;
1656
1657 skb->dev = NULL;
1658
1659 bh_lock_sock_nested(sk);
1660 ret = 0;
1661 if (!sock_owned_by_user(sk)) {
1662#ifdef CONFIG_NET_DMA
1663 struct tcp_sock *tp = tcp_sk(sk);
1664 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1665 tp->ucopy.dma_chan = get_softnet_dma();
1666 if (tp->ucopy.dma_chan)
1667 ret = tcp_v4_do_rcv(sk, skb);
1668 else
1669#endif
1670 {
1671 if (!tcp_prequeue(sk, skb))
1672 ret = tcp_v4_do_rcv(sk, skb);
1673 }
1674 } else
1675 sk_add_backlog(sk, skb);
1676 bh_unlock_sock(sk);
1677
1678 sock_put(sk);
1679
1680 return ret;
1681
1682no_tcp_socket:
1683 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1684 goto discard_it;
1685
1686 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1687bad_packet:
1688 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1689 } else {
1690 tcp_v4_send_reset(NULL, skb);
1691 }
1692
1693discard_it:
1694 /* Discard frame. */
1695 kfree_skb(skb);
1696 return 0;
1697
1698discard_and_relse:
1699 sock_put(sk);
1700 goto discard_it;
1701
1702do_time_wait:
1703 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1704 inet_twsk_put(inet_twsk(sk));
1705 goto discard_it;
1706 }
1707
1708 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1709 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1710 inet_twsk_put(inet_twsk(sk));
1711 goto discard_it;
1712 }
1713 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1714 case TCP_TW_SYN: {
1715 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1716 &tcp_hashinfo,
1717 iph->daddr, th->dest,
1718 inet_iif(skb));
1719 if (sk2) {
1720 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1721 inet_twsk_put(inet_twsk(sk));
1722 sk = sk2;
1723 goto process;
1724 }
1725 /* Fall through to ACK */
1726 }
1727 case TCP_TW_ACK:
1728 tcp_v4_timewait_ack(sk, skb);
1729 break;
1730 case TCP_TW_RST:
1731 goto no_tcp_socket;
1732 case TCP_TW_SUCCESS:;
1733 }
1734 goto discard_it;
1735}
1736
1737/* VJ's idea. Save last timestamp seen from this destination
1738 * and hold it at least for normal timewait interval to use for duplicate
1739 * segment detection in subsequent connections, before they enter synchronized
1740 * state.
1741 */
1742
1743int tcp_v4_remember_stamp(struct sock *sk)
1744{
1745 struct inet_sock *inet = inet_sk(sk);
1746 struct tcp_sock *tp = tcp_sk(sk);
1747 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1748 struct inet_peer *peer = NULL;
1749 int release_it = 0;
1750
1751 if (!rt || rt->rt_dst != inet->daddr) {
1752 peer = inet_getpeer(inet->daddr, 1);
1753 release_it = 1;
1754 } else {
1755 if (!rt->peer)
1756 rt_bind_peer(rt, 1);
1757 peer = rt->peer;
1758 }
1759
1760 if (peer) {
1761 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1762 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1763 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1764 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1765 peer->tcp_ts = tp->rx_opt.ts_recent;
1766 }
1767 if (release_it)
1768 inet_putpeer(peer);
1769 return 1;
1770 }
1771
1772 return 0;
1773}
1774
1775int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1776{
1777 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1778
1779 if (peer) {
1780 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1781
1782 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1783 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1784 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1785 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1786 peer->tcp_ts = tcptw->tw_ts_recent;
1787 }
1788 inet_putpeer(peer);
1789 return 1;
1790 }
1791
1792 return 0;
1793}
1794
1795struct inet_connection_sock_af_ops ipv4_specific = {
1796 .queue_xmit = ip_queue_xmit,
1797 .send_check = tcp_v4_send_check,
1798 .rebuild_header = inet_sk_rebuild_header,
1799 .conn_request = tcp_v4_conn_request,
1800 .syn_recv_sock = tcp_v4_syn_recv_sock,
1801 .remember_stamp = tcp_v4_remember_stamp,
1802 .net_header_len = sizeof(struct iphdr),
1803 .setsockopt = ip_setsockopt,
1804 .getsockopt = ip_getsockopt,
1805 .addr2sockaddr = inet_csk_addr2sockaddr,
1806 .sockaddr_len = sizeof(struct sockaddr_in),
1807 .bind_conflict = inet_csk_bind_conflict,
1808#ifdef CONFIG_COMPAT
1809 .compat_setsockopt = compat_ip_setsockopt,
1810 .compat_getsockopt = compat_ip_getsockopt,
1811#endif
1812};
1813
1814#ifdef CONFIG_TCP_MD5SIG
1815static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1816 .md5_lookup = tcp_v4_md5_lookup,
1817 .calc_md5_hash = tcp_v4_calc_md5_hash,
1818 .md5_add = tcp_v4_md5_add_func,
1819 .md5_parse = tcp_v4_parse_md5_keys,
1820};
1821#endif
1822
1823/* NOTE: A lot of things set to zero explicitly by call to
1824 * sk_alloc() so need not be done here.
1825 */
1826static int tcp_v4_init_sock(struct sock *sk)
1827{
1828 struct inet_connection_sock *icsk = inet_csk(sk);
1829 struct tcp_sock *tp = tcp_sk(sk);
1830
1831 skb_queue_head_init(&tp->out_of_order_queue);
1832 tcp_init_xmit_timers(sk);
1833 tcp_prequeue_init(tp);
1834
1835 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1836 tp->mdev = TCP_TIMEOUT_INIT;
1837
1838 /* So many TCP implementations out there (incorrectly) count the
1839 * initial SYN frame in their delayed-ACK and congestion control
1840 * algorithms that we must have the following bandaid to talk
1841 * efficiently to them. -DaveM
1842 */
1843 tp->snd_cwnd = 2;
1844
1845 /* See draft-stevens-tcpca-spec-01 for discussion of the
1846 * initialization of these values.
1847 */
1848 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1849 tp->snd_cwnd_clamp = ~0;
1850 tp->mss_cache = 536;
1851
1852 tp->reordering = sysctl_tcp_reordering;
1853 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1854
1855 sk->sk_state = TCP_CLOSE;
1856
1857 sk->sk_write_space = sk_stream_write_space;
1858 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1859
1860 icsk->icsk_af_ops = &ipv4_specific;
1861 icsk->icsk_sync_mss = tcp_sync_mss;
1862#ifdef CONFIG_TCP_MD5SIG
1863 tp->af_specific = &tcp_sock_ipv4_specific;
1864#endif
1865
1866 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1867 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1868
1869 atomic_inc(&tcp_sockets_allocated);
1870
1871 return 0;
1872}
1873
1874int tcp_v4_destroy_sock(struct sock *sk)
1875{
1876 struct tcp_sock *tp = tcp_sk(sk);
1877
1878 tcp_clear_xmit_timers(sk);
1879
1880 tcp_cleanup_congestion_control(sk);
1881
1882 /* Cleanup up the write buffer. */
1883 tcp_write_queue_purge(sk);
1884
1885 /* Cleans up our, hopefully empty, out_of_order_queue. */
1886 __skb_queue_purge(&tp->out_of_order_queue);
1887
1888#ifdef CONFIG_TCP_MD5SIG
1889 /* Clean up the MD5 key list, if any */
1890 if (tp->md5sig_info) {
1891 tcp_v4_clear_md5_list(sk);
1892 kfree(tp->md5sig_info);
1893 tp->md5sig_info = NULL;
1894 }
1895#endif
1896
1897#ifdef CONFIG_NET_DMA
1898 /* Cleans up our sk_async_wait_queue */
1899 __skb_queue_purge(&sk->sk_async_wait_queue);
1900#endif
1901
1902 /* Clean prequeue, it must be empty really */
1903 __skb_queue_purge(&tp->ucopy.prequeue);
1904
1905 /* Clean up a referenced TCP bind bucket. */
1906 if (inet_csk(sk)->icsk_bind_hash)
1907 inet_put_port(sk);
1908
1909 /*
1910 * If sendmsg cached page exists, toss it.
1911 */
1912 if (sk->sk_sndmsg_page) {
1913 __free_page(sk->sk_sndmsg_page);
1914 sk->sk_sndmsg_page = NULL;
1915 }
1916
1917 atomic_dec(&tcp_sockets_allocated);
1918
1919 return 0;
1920}
1921
1922EXPORT_SYMBOL(tcp_v4_destroy_sock);
1923
1924#ifdef CONFIG_PROC_FS
1925/* Proc filesystem TCP sock list dumping. */
1926
1927static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1928{
1929 return hlist_empty(head) ? NULL :
1930 list_entry(head->first, struct inet_timewait_sock, tw_node);
1931}
1932
1933static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1934{
1935 return tw->tw_node.next ?
1936 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1937}
1938
1939static void *listening_get_next(struct seq_file *seq, void *cur)
1940{
1941 struct inet_connection_sock *icsk;
1942 struct hlist_node *node;
1943 struct sock *sk = cur;
1944 struct tcp_iter_state* st = seq->private;
1945 struct net *net = seq_file_net(seq);
1946
1947 if (!sk) {
1948 st->bucket = 0;
1949 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1950 goto get_sk;
1951 }
1952
1953 ++st->num;
1954
1955 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1956 struct request_sock *req = cur;
1957
1958 icsk = inet_csk(st->syn_wait_sk);
1959 req = req->dl_next;
1960 while (1) {
1961 while (req) {
1962 if (req->rsk_ops->family == st->family &&
1963 net_eq(sock_net(req->sk), net)) {
1964 cur = req;
1965 goto out;
1966 }
1967 req = req->dl_next;
1968 }
1969 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1970 break;
1971get_req:
1972 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1973 }
1974 sk = sk_next(st->syn_wait_sk);
1975 st->state = TCP_SEQ_STATE_LISTENING;
1976 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1977 } else {
1978 icsk = inet_csk(sk);
1979 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1980 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1981 goto start_req;
1982 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1983 sk = sk_next(sk);
1984 }
1985get_sk:
1986 sk_for_each_from(sk, node) {
1987 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
1988 cur = sk;
1989 goto out;
1990 }
1991 icsk = inet_csk(sk);
1992 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1993 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1994start_req:
1995 st->uid = sock_i_uid(sk);
1996 st->syn_wait_sk = sk;
1997 st->state = TCP_SEQ_STATE_OPENREQ;
1998 st->sbucket = 0;
1999 goto get_req;
2000 }
2001 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2002 }
2003 if (++st->bucket < INET_LHTABLE_SIZE) {
2004 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
2005 goto get_sk;
2006 }
2007 cur = NULL;
2008out:
2009 return cur;
2010}
2011
2012static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2013{
2014 void *rc = listening_get_next(seq, NULL);
2015
2016 while (rc && *pos) {
2017 rc = listening_get_next(seq, rc);
2018 --*pos;
2019 }
2020 return rc;
2021}
2022
2023static void *established_get_first(struct seq_file *seq)
2024{
2025 struct tcp_iter_state* st = seq->private;
2026 struct net *net = seq_file_net(seq);
2027 void *rc = NULL;
2028
2029 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2030 struct sock *sk;
2031 struct hlist_node *node;
2032 struct inet_timewait_sock *tw;
2033 rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2034
2035 read_lock_bh(lock);
2036 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2037 if (sk->sk_family != st->family ||
2038 !net_eq(sock_net(sk), net)) {
2039 continue;
2040 }
2041 rc = sk;
2042 goto out;
2043 }
2044 st->state = TCP_SEQ_STATE_TIME_WAIT;
2045 inet_twsk_for_each(tw, node,
2046 &tcp_hashinfo.ehash[st->bucket].twchain) {
2047 if (tw->tw_family != st->family ||
2048 !net_eq(twsk_net(tw), net)) {
2049 continue;
2050 }
2051 rc = tw;
2052 goto out;
2053 }
2054 read_unlock_bh(lock);
2055 st->state = TCP_SEQ_STATE_ESTABLISHED;
2056 }
2057out:
2058 return rc;
2059}
2060
2061static void *established_get_next(struct seq_file *seq, void *cur)
2062{
2063 struct sock *sk = cur;
2064 struct inet_timewait_sock *tw;
2065 struct hlist_node *node;
2066 struct tcp_iter_state* st = seq->private;
2067 struct net *net = seq_file_net(seq);
2068
2069 ++st->num;
2070
2071 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2072 tw = cur;
2073 tw = tw_next(tw);
2074get_tw:
2075 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2076 tw = tw_next(tw);
2077 }
2078 if (tw) {
2079 cur = tw;
2080 goto out;
2081 }
2082 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2083 st->state = TCP_SEQ_STATE_ESTABLISHED;
2084
2085 if (++st->bucket < tcp_hashinfo.ehash_size) {
2086 read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2087 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
2088 } else {
2089 cur = NULL;
2090 goto out;
2091 }
2092 } else
2093 sk = sk_next(sk);
2094
2095 sk_for_each_from(sk, node) {
2096 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2097 goto found;
2098 }
2099
2100 st->state = TCP_SEQ_STATE_TIME_WAIT;
2101 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2102 goto get_tw;
2103found:
2104 cur = sk;
2105out:
2106 return cur;
2107}
2108
2109static void *established_get_idx(struct seq_file *seq, loff_t pos)
2110{
2111 void *rc = established_get_first(seq);
2112
2113 while (rc && pos) {
2114 rc = established_get_next(seq, rc);
2115 --pos;
2116 }
2117 return rc;
2118}
2119
2120static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2121{
2122 void *rc;
2123 struct tcp_iter_state* st = seq->private;
2124
2125 inet_listen_lock(&tcp_hashinfo);
2126 st->state = TCP_SEQ_STATE_LISTENING;
2127 rc = listening_get_idx(seq, &pos);
2128
2129 if (!rc) {
2130 inet_listen_unlock(&tcp_hashinfo);
2131 st->state = TCP_SEQ_STATE_ESTABLISHED;
2132 rc = established_get_idx(seq, pos);
2133 }
2134
2135 return rc;
2136}
2137
2138static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2139{
2140 struct tcp_iter_state* st = seq->private;
2141 st->state = TCP_SEQ_STATE_LISTENING;
2142 st->num = 0;
2143 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2144}
2145
2146static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2147{
2148 void *rc = NULL;
2149 struct tcp_iter_state* st;
2150
2151 if (v == SEQ_START_TOKEN) {
2152 rc = tcp_get_idx(seq, 0);
2153 goto out;
2154 }
2155 st = seq->private;
2156
2157 switch (st->state) {
2158 case TCP_SEQ_STATE_OPENREQ:
2159 case TCP_SEQ_STATE_LISTENING:
2160 rc = listening_get_next(seq, v);
2161 if (!rc) {
2162 inet_listen_unlock(&tcp_hashinfo);
2163 st->state = TCP_SEQ_STATE_ESTABLISHED;
2164 rc = established_get_first(seq);
2165 }
2166 break;
2167 case TCP_SEQ_STATE_ESTABLISHED:
2168 case TCP_SEQ_STATE_TIME_WAIT:
2169 rc = established_get_next(seq, v);
2170 break;
2171 }
2172out:
2173 ++*pos;
2174 return rc;
2175}
2176
2177static void tcp_seq_stop(struct seq_file *seq, void *v)
2178{
2179 struct tcp_iter_state* st = seq->private;
2180
2181 switch (st->state) {
2182 case TCP_SEQ_STATE_OPENREQ:
2183 if (v) {
2184 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2185 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2186 }
2187 case TCP_SEQ_STATE_LISTENING:
2188 if (v != SEQ_START_TOKEN)
2189 inet_listen_unlock(&tcp_hashinfo);
2190 break;
2191 case TCP_SEQ_STATE_TIME_WAIT:
2192 case TCP_SEQ_STATE_ESTABLISHED:
2193 if (v)
2194 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2195 break;
2196 }
2197}
2198
2199static int tcp_seq_open(struct inode *inode, struct file *file)
2200{
2201 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2202 struct tcp_iter_state *s;
2203 int err;
2204
2205 err = seq_open_net(inode, file, &afinfo->seq_ops,
2206 sizeof(struct tcp_iter_state));
2207 if (err < 0)
2208 return err;
2209
2210 s = ((struct seq_file *)file->private_data)->private;
2211 s->family = afinfo->family;
2212 return 0;
2213}
2214
2215int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2216{
2217 int rc = 0;
2218 struct proc_dir_entry *p;
2219
2220 afinfo->seq_fops.open = tcp_seq_open;
2221 afinfo->seq_fops.read = seq_read;
2222 afinfo->seq_fops.llseek = seq_lseek;
2223 afinfo->seq_fops.release = seq_release_net;
2224
2225 afinfo->seq_ops.start = tcp_seq_start;
2226 afinfo->seq_ops.next = tcp_seq_next;
2227 afinfo->seq_ops.stop = tcp_seq_stop;
2228
2229 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2230 &afinfo->seq_fops, afinfo);
2231 if (!p)
2232 rc = -ENOMEM;
2233 return rc;
2234}
2235
2236void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2237{
2238 proc_net_remove(net, afinfo->name);
2239}
2240
2241static void get_openreq4(struct sock *sk, struct request_sock *req,
2242 struct seq_file *f, int i, int uid, int *len)
2243{
2244 const struct inet_request_sock *ireq = inet_rsk(req);
2245 int ttd = req->expires - jiffies;
2246
2247 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2248 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2249 i,
2250 ireq->loc_addr,
2251 ntohs(inet_sk(sk)->sport),
2252 ireq->rmt_addr,
2253 ntohs(ireq->rmt_port),
2254 TCP_SYN_RECV,
2255 0, 0, /* could print option size, but that is af dependent. */
2256 1, /* timers active (only the expire timer) */
2257 jiffies_to_clock_t(ttd),
2258 req->retrans,
2259 uid,
2260 0, /* non standard timer */
2261 0, /* open_requests have no inode */
2262 atomic_read(&sk->sk_refcnt),
2263 req,
2264 len);
2265}
2266
2267static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2268{
2269 int timer_active;
2270 unsigned long timer_expires;
2271 struct tcp_sock *tp = tcp_sk(sk);
2272 const struct inet_connection_sock *icsk = inet_csk(sk);
2273 struct inet_sock *inet = inet_sk(sk);
2274 __be32 dest = inet->daddr;
2275 __be32 src = inet->rcv_saddr;
2276 __u16 destp = ntohs(inet->dport);
2277 __u16 srcp = ntohs(inet->sport);
2278
2279 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2280 timer_active = 1;
2281 timer_expires = icsk->icsk_timeout;
2282 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2283 timer_active = 4;
2284 timer_expires = icsk->icsk_timeout;
2285 } else if (timer_pending(&sk->sk_timer)) {
2286 timer_active = 2;
2287 timer_expires = sk->sk_timer.expires;
2288 } else {
2289 timer_active = 0;
2290 timer_expires = jiffies;
2291 }
2292
2293 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2294 "%08X %5d %8d %lu %d %p %u %u %u %u %d%n",
2295 i, src, srcp, dest, destp, sk->sk_state,
2296 tp->write_seq - tp->snd_una,
2297 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2298 (tp->rcv_nxt - tp->copied_seq),
2299 timer_active,
2300 jiffies_to_clock_t(timer_expires - jiffies),
2301 icsk->icsk_retransmits,
2302 sock_i_uid(sk),
2303 icsk->icsk_probes_out,
2304 sock_i_ino(sk),
2305 atomic_read(&sk->sk_refcnt), sk,
2306 icsk->icsk_rto,
2307 icsk->icsk_ack.ato,
2308 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2309 tp->snd_cwnd,
2310 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2311 len);
2312}
2313
2314static void get_timewait4_sock(struct inet_timewait_sock *tw,
2315 struct seq_file *f, int i, int *len)
2316{
2317 __be32 dest, src;
2318 __u16 destp, srcp;
2319 int ttd = tw->tw_ttd - jiffies;
2320
2321 if (ttd < 0)
2322 ttd = 0;
2323
2324 dest = tw->tw_daddr;
2325 src = tw->tw_rcv_saddr;
2326 destp = ntohs(tw->tw_dport);
2327 srcp = ntohs(tw->tw_sport);
2328
2329 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2330 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2331 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2332 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2333 atomic_read(&tw->tw_refcnt), tw, len);
2334}
2335
2336#define TMPSZ 150
2337
2338static int tcp4_seq_show(struct seq_file *seq, void *v)
2339{
2340 struct tcp_iter_state* st;
2341 int len;
2342
2343 if (v == SEQ_START_TOKEN) {
2344 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2345 " sl local_address rem_address st tx_queue "
2346 "rx_queue tr tm->when retrnsmt uid timeout "
2347 "inode");
2348 goto out;
2349 }
2350 st = seq->private;
2351
2352 switch (st->state) {
2353 case TCP_SEQ_STATE_LISTENING:
2354 case TCP_SEQ_STATE_ESTABLISHED:
2355 get_tcp4_sock(v, seq, st->num, &len);
2356 break;
2357 case TCP_SEQ_STATE_OPENREQ:
2358 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2359 break;
2360 case TCP_SEQ_STATE_TIME_WAIT:
2361 get_timewait4_sock(v, seq, st->num, &len);
2362 break;
2363 }
2364 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2365out:
2366 return 0;
2367}
2368
2369static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2370 .name = "tcp",
2371 .family = AF_INET,
2372 .seq_fops = {
2373 .owner = THIS_MODULE,
2374 },
2375 .seq_ops = {
2376 .show = tcp4_seq_show,
2377 },
2378};
2379
2380static int tcp4_proc_init_net(struct net *net)
2381{
2382 return tcp_proc_register(net, &tcp4_seq_afinfo);
2383}
2384
2385static void tcp4_proc_exit_net(struct net *net)
2386{
2387 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2388}
2389
2390static struct pernet_operations tcp4_net_ops = {
2391 .init = tcp4_proc_init_net,
2392 .exit = tcp4_proc_exit_net,
2393};
2394
2395int __init tcp4_proc_init(void)
2396{
2397 return register_pernet_subsys(&tcp4_net_ops);
2398}
2399
2400void tcp4_proc_exit(void)
2401{
2402 unregister_pernet_subsys(&tcp4_net_ops);
2403}
2404#endif /* CONFIG_PROC_FS */
2405
2406struct proto tcp_prot = {
2407 .name = "TCP",
2408 .owner = THIS_MODULE,
2409 .close = tcp_close,
2410 .connect = tcp_v4_connect,
2411 .disconnect = tcp_disconnect,
2412 .accept = inet_csk_accept,
2413 .ioctl = tcp_ioctl,
2414 .init = tcp_v4_init_sock,
2415 .destroy = tcp_v4_destroy_sock,
2416 .shutdown = tcp_shutdown,
2417 .setsockopt = tcp_setsockopt,
2418 .getsockopt = tcp_getsockopt,
2419 .recvmsg = tcp_recvmsg,
2420 .backlog_rcv = tcp_v4_do_rcv,
2421 .hash = inet_hash,
2422 .unhash = inet_unhash,
2423 .get_port = inet_csk_get_port,
2424 .enter_memory_pressure = tcp_enter_memory_pressure,
2425 .sockets_allocated = &tcp_sockets_allocated,
2426 .orphan_count = &tcp_orphan_count,
2427 .memory_allocated = &tcp_memory_allocated,
2428 .memory_pressure = &tcp_memory_pressure,
2429 .sysctl_mem = sysctl_tcp_mem,
2430 .sysctl_wmem = sysctl_tcp_wmem,
2431 .sysctl_rmem = sysctl_tcp_rmem,
2432 .max_header = MAX_TCP_HEADER,
2433 .obj_size = sizeof(struct tcp_sock),
2434 .twsk_prot = &tcp_timewait_sock_ops,
2435 .rsk_prot = &tcp_request_sock_ops,
2436 .h.hashinfo = &tcp_hashinfo,
2437#ifdef CONFIG_COMPAT
2438 .compat_setsockopt = compat_tcp_setsockopt,
2439 .compat_getsockopt = compat_tcp_getsockopt,
2440#endif
2441};
2442
2443
2444static int __net_init tcp_sk_init(struct net *net)
2445{
2446 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2447 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2448}
2449
2450static void __net_exit tcp_sk_exit(struct net *net)
2451{
2452 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2453}
2454
2455static struct pernet_operations __net_initdata tcp_sk_ops = {
2456 .init = tcp_sk_init,
2457 .exit = tcp_sk_exit,
2458};
2459
2460void __init tcp_v4_init(void)
2461{
2462 if (register_pernet_device(&tcp_sk_ops))
2463 panic("Failed to create the TCP control socket.\n");
2464}
2465
2466EXPORT_SYMBOL(ipv4_specific);
2467EXPORT_SYMBOL(tcp_hashinfo);
2468EXPORT_SYMBOL(tcp_prot);
2469EXPORT_SYMBOL(tcp_v4_conn_request);
2470EXPORT_SYMBOL(tcp_v4_connect);
2471EXPORT_SYMBOL(tcp_v4_do_rcv);
2472EXPORT_SYMBOL(tcp_v4_remember_stamp);
2473EXPORT_SYMBOL(tcp_v4_send_check);
2474EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2475
2476#ifdef CONFIG_PROC_FS
2477EXPORT_SYMBOL(tcp_proc_register);
2478EXPORT_SYMBOL(tcp_proc_unregister);
2479#endif
2480EXPORT_SYMBOL(sysctl_tcp_low_latency);
2481