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sound: seq_midi_event: fix decoding of (N)RPN events
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv4 / tcp_ipv4.c
blob5499c2876f468a78996a7f5664e11d4a484893c6
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24 /*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53
54 #include <linux/bottom_half.h>
55 #include <linux/types.h>
56 #include <linux/fcntl.h>
57 #include <linux/module.h>
58 #include <linux/random.h>
59 #include <linux/cache.h>
60 #include <linux/jhash.h>
61 #include <linux/init.h>
62 #include <linux/times.h>
63
64 #include <net/net_namespace.h>
65 #include <net/icmp.h>
66 #include <net/inet_hashtables.h>
67 #include <net/tcp.h>
68 #include <net/transp_v6.h>
69 #include <net/ipv6.h>
70 #include <net/inet_common.h>
71 #include <net/timewait_sock.h>
72 #include <net/xfrm.h>
73 #include <net/netdma.h>
74
75 #include <linux/inet.h>
76 #include <linux/ipv6.h>
77 #include <linux/stddef.h>
78 #include <linux/proc_fs.h>
79 #include <linux/seq_file.h>
80
81 #include <linux/crypto.h>
82 #include <linux/scatterlist.h>
83
84 int sysctl_tcp_tw_reuse __read_mostly;
85 int sysctl_tcp_low_latency __read_mostly;
86
87
88 #ifdef CONFIG_TCP_MD5SIG
89 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
90 __be32 addr);
91 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
92 __be32 daddr, __be32 saddr, struct tcphdr *th);
93 #else
94 static inline
95 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
96 {
97 return NULL;
98 }
99 #endif
100
101 struct inet_hashinfo tcp_hashinfo;
102
103 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
104 {
105 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
106 ip_hdr(skb)->saddr,
107 tcp_hdr(skb)->dest,
108 tcp_hdr(skb)->source);
109 }
110
111 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112 {
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 /* With PAWS, it is safe from the viewpoint
117 of data integrity. Even without PAWS it is safe provided sequence
118 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119
120 Actually, the idea is close to VJ's one, only timestamp cache is
121 held not per host, but per port pair and TW bucket is used as state
122 holder.
123
124 If TW bucket has been already destroyed we fall back to VJ's scheme
125 and use initial timestamp retrieved from peer table.
126 */
127 if (tcptw->tw_ts_recent_stamp &&
128 (twp == NULL || (sysctl_tcp_tw_reuse &&
129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
131 if (tp->write_seq == 0)
132 tp->write_seq = 1;
133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
135 sock_hold(sktw);
136 return 1;
137 }
138
139 return 0;
140 }
141
142 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
143
144 /* This will initiate an outgoing connection. */
145 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
146 {
147 struct inet_sock *inet = inet_sk(sk);
148 struct tcp_sock *tp = tcp_sk(sk);
149 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
150 struct rtable *rt;
151 __be32 daddr, nexthop;
152 int tmp;
153 int err;
154
155 if (addr_len < sizeof(struct sockaddr_in))
156 return -EINVAL;
157
158 if (usin->sin_family != AF_INET)
159 return -EAFNOSUPPORT;
160
161 nexthop = daddr = usin->sin_addr.s_addr;
162 if (inet->opt && inet->opt->srr) {
163 if (!daddr)
164 return -EINVAL;
165 nexthop = inet->opt->faddr;
166 }
167
168 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
169 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
170 IPPROTO_TCP,
171 inet->sport, usin->sin_port, sk, 1);
172 if (tmp < 0) {
173 if (tmp == -ENETUNREACH)
174 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
175 return tmp;
176 }
177
178 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
179 ip_rt_put(rt);
180 return -ENETUNREACH;
181 }
182
183 if (!inet->opt || !inet->opt->srr)
184 daddr = rt->rt_dst;
185
186 if (!inet->saddr)
187 inet->saddr = rt->rt_src;
188 inet->rcv_saddr = inet->saddr;
189
190 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
191 /* Reset inherited state */
192 tp->rx_opt.ts_recent = 0;
193 tp->rx_opt.ts_recent_stamp = 0;
194 tp->write_seq = 0;
195 }
196
197 if (tcp_death_row.sysctl_tw_recycle &&
198 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
199 struct inet_peer *peer = rt_get_peer(rt);
200 /*
201 * VJ's idea. We save last timestamp seen from
202 * the destination in peer table, when entering state
203 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
204 * when trying new connection.
205 */
206 if (peer != NULL &&
207 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
208 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
209 tp->rx_opt.ts_recent = peer->tcp_ts;
210 }
211 }
212
213 inet->dport = usin->sin_port;
214 inet->daddr = daddr;
215
216 inet_csk(sk)->icsk_ext_hdr_len = 0;
217 if (inet->opt)
218 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
219
220 tp->rx_opt.mss_clamp = 536;
221
222 /* Socket identity is still unknown (sport may be zero).
223 * However we set state to SYN-SENT and not releasing socket
224 * lock select source port, enter ourselves into the hash tables and
225 * complete initialization after this.
226 */
227 tcp_set_state(sk, TCP_SYN_SENT);
228 err = inet_hash_connect(&tcp_death_row, sk);
229 if (err)
230 goto failure;
231
232 err = ip_route_newports(&rt, IPPROTO_TCP,
233 inet->sport, inet->dport, sk);
234 if (err)
235 goto failure;
236
237 /* OK, now commit destination to socket. */
238 sk->sk_gso_type = SKB_GSO_TCPV4;
239 sk_setup_caps(sk, &rt->u.dst);
240
241 if (!tp->write_seq)
242 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
243 inet->daddr,
244 inet->sport,
245 usin->sin_port);
246
247 inet->id = tp->write_seq ^ jiffies;
248
249 err = tcp_connect(sk);
250 rt = NULL;
251 if (err)
252 goto failure;
253
254 return 0;
255
256 failure:
257 /*
258 * This unhashes the socket and releases the local port,
259 * if necessary.
260 */
261 tcp_set_state(sk, TCP_CLOSE);
262 ip_rt_put(rt);
263 sk->sk_route_caps = 0;
264 inet->dport = 0;
265 return err;
266 }
267
268 /*
269 * This routine does path mtu discovery as defined in RFC1191.
270 */
271 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
272 {
273 struct dst_entry *dst;
274 struct inet_sock *inet = inet_sk(sk);
275
276 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
277 * send out by Linux are always <576bytes so they should go through
278 * unfragmented).
279 */
280 if (sk->sk_state == TCP_LISTEN)
281 return;
282
283 /* We don't check in the destentry if pmtu discovery is forbidden
284 * on this route. We just assume that no packet_to_big packets
285 * are send back when pmtu discovery is not active.
286 * There is a small race when the user changes this flag in the
287 * route, but I think that's acceptable.
288 */
289 if ((dst = __sk_dst_check(sk, 0)) == NULL)
290 return;
291
292 dst->ops->update_pmtu(dst, mtu);
293
294 /* Something is about to be wrong... Remember soft error
295 * for the case, if this connection will not able to recover.
296 */
297 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
298 sk->sk_err_soft = EMSGSIZE;
299
300 mtu = dst_mtu(dst);
301
302 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
303 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
304 tcp_sync_mss(sk, mtu);
305
306 /* Resend the TCP packet because it's
307 * clear that the old packet has been
308 * dropped. This is the new "fast" path mtu
309 * discovery.
310 */
311 tcp_simple_retransmit(sk);
312 } /* else let the usual retransmit timer handle it */
313 }
314
315 /*
316 * This routine is called by the ICMP module when it gets some
317 * sort of error condition. If err < 0 then the socket should
318 * be closed and the error returned to the user. If err > 0
319 * it's just the icmp type << 8 | icmp code. After adjustment
320 * header points to the first 8 bytes of the tcp header. We need
321 * to find the appropriate port.
322 *
323 * The locking strategy used here is very "optimistic". When
324 * someone else accesses the socket the ICMP is just dropped
325 * and for some paths there is no check at all.
326 * A more general error queue to queue errors for later handling
327 * is probably better.
328 *
329 */
330
331 void tcp_v4_err(struct sk_buff *skb, u32 info)
332 {
333 struct iphdr *iph = (struct iphdr *)skb->data;
334 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
335 struct tcp_sock *tp;
336 struct inet_sock *inet;
337 const int type = icmp_hdr(skb)->type;
338 const int code = icmp_hdr(skb)->code;
339 struct sock *sk;
340 __u32 seq;
341 int err;
342 struct net *net = dev_net(skb->dev);
343
344 if (skb->len < (iph->ihl << 2) + 8) {
345 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
346 return;
347 }
348
349 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
350 iph->saddr, th->source, inet_iif(skb));
351 if (!sk) {
352 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
353 return;
354 }
355 if (sk->sk_state == TCP_TIME_WAIT) {
356 inet_twsk_put(inet_twsk(sk));
357 return;
358 }
359
360 bh_lock_sock(sk);
361 /* If too many ICMPs get dropped on busy
362 * servers this needs to be solved differently.
363 */
364 if (sock_owned_by_user(sk))
365 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
366
367 if (sk->sk_state == TCP_CLOSE)
368 goto out;
369
370 tp = tcp_sk(sk);
371 seq = ntohl(th->seq);
372 if (sk->sk_state != TCP_LISTEN &&
373 !between(seq, tp->snd_una, tp->snd_nxt)) {
374 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
375 goto out;
376 }
377
378 switch (type) {
379 case ICMP_SOURCE_QUENCH:
380 /* Just silently ignore these. */
381 goto out;
382 case ICMP_PARAMETERPROB:
383 err = EPROTO;
384 break;
385 case ICMP_DEST_UNREACH:
386 if (code > NR_ICMP_UNREACH)
387 goto out;
388
389 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
390 if (!sock_owned_by_user(sk))
391 do_pmtu_discovery(sk, iph, info);
392 goto out;
393 }
394
395 err = icmp_err_convert[code].errno;
396 break;
397 case ICMP_TIME_EXCEEDED:
398 err = EHOSTUNREACH;
399 break;
400 default:
401 goto out;
402 }
403
404 switch (sk->sk_state) {
405 struct request_sock *req, **prev;
406 case TCP_LISTEN:
407 if (sock_owned_by_user(sk))
408 goto out;
409
410 req = inet_csk_search_req(sk, &prev, th->dest,
411 iph->daddr, iph->saddr);
412 if (!req)
413 goto out;
414
415 /* ICMPs are not backlogged, hence we cannot get
416 an established socket here.
417 */
418 WARN_ON(req->sk);
419
420 if (seq != tcp_rsk(req)->snt_isn) {
421 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
422 goto out;
423 }
424
425 /*
426 * Still in SYN_RECV, just remove it silently.
427 * There is no good way to pass the error to the newly
428 * created socket, and POSIX does not want network
429 * errors returned from accept().
430 */
431 inet_csk_reqsk_queue_drop(sk, req, prev);
432 goto out;
433
434 case TCP_SYN_SENT:
435 case TCP_SYN_RECV: /* Cannot happen.
436 It can f.e. if SYNs crossed.
437 */
438 if (!sock_owned_by_user(sk)) {
439 sk->sk_err = err;
440
441 sk->sk_error_report(sk);
442
443 tcp_done(sk);
444 } else {
445 sk->sk_err_soft = err;
446 }
447 goto out;
448 }
449
450 /* If we've already connected we will keep trying
451 * until we time out, or the user gives up.
452 *
453 * rfc1122 4.2.3.9 allows to consider as hard errors
454 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
455 * but it is obsoleted by pmtu discovery).
456 *
457 * Note, that in modern internet, where routing is unreliable
458 * and in each dark corner broken firewalls sit, sending random
459 * errors ordered by their masters even this two messages finally lose
460 * their original sense (even Linux sends invalid PORT_UNREACHs)
461 *
462 * Now we are in compliance with RFCs.
463 * --ANK (980905)
464 */
465
466 inet = inet_sk(sk);
467 if (!sock_owned_by_user(sk) && inet->recverr) {
468 sk->sk_err = err;
469 sk->sk_error_report(sk);
470 } else { /* Only an error on timeout */
471 sk->sk_err_soft = err;
472 }
473
474 out:
475 bh_unlock_sock(sk);
476 sock_put(sk);
477 }
478
479 /* This routine computes an IPv4 TCP checksum. */
480 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
481 {
482 struct inet_sock *inet = inet_sk(sk);
483 struct tcphdr *th = tcp_hdr(skb);
484
485 if (skb->ip_summed == CHECKSUM_PARTIAL) {
486 th->check = ~tcp_v4_check(len, inet->saddr,
487 inet->daddr, 0);
488 skb->csum_start = skb_transport_header(skb) - skb->head;
489 skb->csum_offset = offsetof(struct tcphdr, check);
490 } else {
491 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
492 csum_partial(th,
493 th->doff << 2,
494 skb->csum));
495 }
496 }
497
498 int tcp_v4_gso_send_check(struct sk_buff *skb)
499 {
500 const struct iphdr *iph;
501 struct tcphdr *th;
502
503 if (!pskb_may_pull(skb, sizeof(*th)))
504 return -EINVAL;
505
506 iph = ip_hdr(skb);
507 th = tcp_hdr(skb);
508
509 th->check = 0;
510 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 skb->ip_summed = CHECKSUM_PARTIAL;
514 return 0;
515 }
516
517 /*
518 * This routine will send an RST to the other tcp.
519 *
520 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
521 * for reset.
522 * Answer: if a packet caused RST, it is not for a socket
523 * existing in our system, if it is matched to a socket,
524 * it is just duplicate segment or bug in other side's TCP.
525 * So that we build reply only basing on parameters
526 * arrived with segment.
527 * Exception: precedence violation. We do not implement it in any case.
528 */
529
530 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
531 {
532 struct tcphdr *th = tcp_hdr(skb);
533 struct {
534 struct tcphdr th;
535 #ifdef CONFIG_TCP_MD5SIG
536 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
537 #endif
538 } rep;
539 struct ip_reply_arg arg;
540 #ifdef CONFIG_TCP_MD5SIG
541 struct tcp_md5sig_key *key;
542 #endif
543 struct net *net;
544
545 /* Never send a reset in response to a reset. */
546 if (th->rst)
547 return;
548
549 if (skb->rtable->rt_type != RTN_LOCAL)
550 return;
551
552 /* Swap the send and the receive. */
553 memset(&rep, 0, sizeof(rep));
554 rep.th.dest = th->source;
555 rep.th.source = th->dest;
556 rep.th.doff = sizeof(struct tcphdr) / 4;
557 rep.th.rst = 1;
558
559 if (th->ack) {
560 rep.th.seq = th->ack_seq;
561 } else {
562 rep.th.ack = 1;
563 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
564 skb->len - (th->doff << 2));
565 }
566
567 memset(&arg, 0, sizeof(arg));
568 arg.iov[0].iov_base = (unsigned char *)&rep;
569 arg.iov[0].iov_len = sizeof(rep.th);
570
571 #ifdef CONFIG_TCP_MD5SIG
572 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
573 if (key) {
574 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
575 (TCPOPT_NOP << 16) |
576 (TCPOPT_MD5SIG << 8) |
577 TCPOLEN_MD5SIG);
578 /* Update length and the length the header thinks exists */
579 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
580 rep.th.doff = arg.iov[0].iov_len / 4;
581
582 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
583 key, ip_hdr(skb)->saddr,
584 ip_hdr(skb)->daddr, &rep.th);
585 }
586 #endif
587 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
588 ip_hdr(skb)->saddr, /* XXX */
589 arg.iov[0].iov_len, IPPROTO_TCP, 0);
590 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
591 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
592
593 net = dev_net(skb->dst->dev);
594 ip_send_reply(net->ipv4.tcp_sock, skb,
595 &arg, arg.iov[0].iov_len);
596
597 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
598 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
599 }
600
601 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
602 outside socket context is ugly, certainly. What can I do?
603 */
604
605 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
606 u32 win, u32 ts, int oif,
607 struct tcp_md5sig_key *key,
608 int reply_flags)
609 {
610 struct tcphdr *th = tcp_hdr(skb);
611 struct {
612 struct tcphdr th;
613 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
614 #ifdef CONFIG_TCP_MD5SIG
615 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
616 #endif
617 ];
618 } rep;
619 struct ip_reply_arg arg;
620 struct net *net = dev_net(skb->dst->dev);
621
622 memset(&rep.th, 0, sizeof(struct tcphdr));
623 memset(&arg, 0, sizeof(arg));
624
625 arg.iov[0].iov_base = (unsigned char *)&rep;
626 arg.iov[0].iov_len = sizeof(rep.th);
627 if (ts) {
628 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
629 (TCPOPT_TIMESTAMP << 8) |
630 TCPOLEN_TIMESTAMP);
631 rep.opt[1] = htonl(tcp_time_stamp);
632 rep.opt[2] = htonl(ts);
633 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
634 }
635
636 /* Swap the send and the receive. */
637 rep.th.dest = th->source;
638 rep.th.source = th->dest;
639 rep.th.doff = arg.iov[0].iov_len / 4;
640 rep.th.seq = htonl(seq);
641 rep.th.ack_seq = htonl(ack);
642 rep.th.ack = 1;
643 rep.th.window = htons(win);
644
645 #ifdef CONFIG_TCP_MD5SIG
646 if (key) {
647 int offset = (ts) ? 3 : 0;
648
649 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
650 (TCPOPT_NOP << 16) |
651 (TCPOPT_MD5SIG << 8) |
652 TCPOLEN_MD5SIG);
653 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
654 rep.th.doff = arg.iov[0].iov_len/4;
655
656 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
657 key, ip_hdr(skb)->saddr,
658 ip_hdr(skb)->daddr, &rep.th);
659 }
660 #endif
661 arg.flags = reply_flags;
662 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
663 ip_hdr(skb)->saddr, /* XXX */
664 arg.iov[0].iov_len, IPPROTO_TCP, 0);
665 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
666 if (oif)
667 arg.bound_dev_if = oif;
668
669 ip_send_reply(net->ipv4.tcp_sock, skb,
670 &arg, arg.iov[0].iov_len);
671
672 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
673 }
674
675 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
676 {
677 struct inet_timewait_sock *tw = inet_twsk(sk);
678 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
679
680 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
681 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
682 tcptw->tw_ts_recent,
683 tw->tw_bound_dev_if,
684 tcp_twsk_md5_key(tcptw),
685 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
686 );
687
688 inet_twsk_put(tw);
689 }
690
691 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
692 struct request_sock *req)
693 {
694 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
695 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
696 req->ts_recent,
697 0,
698 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
699 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
700 }
701
702 /*
703 * Send a SYN-ACK after having received a SYN.
704 * This still operates on a request_sock only, not on a big
705 * socket.
706 */
707 static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
708 struct dst_entry *dst)
709 {
710 const struct inet_request_sock *ireq = inet_rsk(req);
711 int err = -1;
712 struct sk_buff * skb;
713
714 /* First, grab a route. */
715 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
716 return -1;
717
718 skb = tcp_make_synack(sk, dst, req);
719
720 if (skb) {
721 struct tcphdr *th = tcp_hdr(skb);
722
723 th->check = tcp_v4_check(skb->len,
724 ireq->loc_addr,
725 ireq->rmt_addr,
726 csum_partial(th, skb->len,
727 skb->csum));
728
729 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
730 ireq->rmt_addr,
731 ireq->opt);
732 err = net_xmit_eval(err);
733 }
734
735 dst_release(dst);
736 return err;
737 }
738
739 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
740 {
741 return __tcp_v4_send_synack(sk, req, NULL);
742 }
743
744 /*
745 * IPv4 request_sock destructor.
746 */
747 static void tcp_v4_reqsk_destructor(struct request_sock *req)
748 {
749 kfree(inet_rsk(req)->opt);
750 }
751
752 #ifdef CONFIG_SYN_COOKIES
753 static void syn_flood_warning(struct sk_buff *skb)
754 {
755 static unsigned long warntime;
756
757 if (time_after(jiffies, (warntime + HZ * 60))) {
758 warntime = jiffies;
759 printk(KERN_INFO
760 "possible SYN flooding on port %d. Sending cookies.\n",
761 ntohs(tcp_hdr(skb)->dest));
762 }
763 }
764 #endif
765
766 /*
767 * Save and compile IPv4 options into the request_sock if needed.
768 */
769 static struct ip_options *tcp_v4_save_options(struct sock *sk,
770 struct sk_buff *skb)
771 {
772 struct ip_options *opt = &(IPCB(skb)->opt);
773 struct ip_options *dopt = NULL;
774
775 if (opt && opt->optlen) {
776 int opt_size = optlength(opt);
777 dopt = kmalloc(opt_size, GFP_ATOMIC);
778 if (dopt) {
779 if (ip_options_echo(dopt, skb)) {
780 kfree(dopt);
781 dopt = NULL;
782 }
783 }
784 }
785 return dopt;
786 }
787
788 #ifdef CONFIG_TCP_MD5SIG
789 /*
790 * RFC2385 MD5 checksumming requires a mapping of
791 * IP address->MD5 Key.
792 * We need to maintain these in the sk structure.
793 */
794
795 /* Find the Key structure for an address. */
796 static struct tcp_md5sig_key *
797 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
798 {
799 struct tcp_sock *tp = tcp_sk(sk);
800 int i;
801
802 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
803 return NULL;
804 for (i = 0; i < tp->md5sig_info->entries4; i++) {
805 if (tp->md5sig_info->keys4[i].addr == addr)
806 return &tp->md5sig_info->keys4[i].base;
807 }
808 return NULL;
809 }
810
811 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
812 struct sock *addr_sk)
813 {
814 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
815 }
816
817 EXPORT_SYMBOL(tcp_v4_md5_lookup);
818
819 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
820 struct request_sock *req)
821 {
822 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
823 }
824
825 /* This can be called on a newly created socket, from other files */
826 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
827 u8 *newkey, u8 newkeylen)
828 {
829 /* Add Key to the list */
830 struct tcp_md5sig_key *key;
831 struct tcp_sock *tp = tcp_sk(sk);
832 struct tcp4_md5sig_key *keys;
833
834 key = tcp_v4_md5_do_lookup(sk, addr);
835 if (key) {
836 /* Pre-existing entry - just update that one. */
837 kfree(key->key);
838 key->key = newkey;
839 key->keylen = newkeylen;
840 } else {
841 struct tcp_md5sig_info *md5sig;
842
843 if (!tp->md5sig_info) {
844 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
845 GFP_ATOMIC);
846 if (!tp->md5sig_info) {
847 kfree(newkey);
848 return -ENOMEM;
849 }
850 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
851 }
852 if (tcp_alloc_md5sig_pool() == NULL) {
853 kfree(newkey);
854 return -ENOMEM;
855 }
856 md5sig = tp->md5sig_info;
857
858 if (md5sig->alloced4 == md5sig->entries4) {
859 keys = kmalloc((sizeof(*keys) *
860 (md5sig->entries4 + 1)), GFP_ATOMIC);
861 if (!keys) {
862 kfree(newkey);
863 tcp_free_md5sig_pool();
864 return -ENOMEM;
865 }
866
867 if (md5sig->entries4)
868 memcpy(keys, md5sig->keys4,
869 sizeof(*keys) * md5sig->entries4);
870
871 /* Free old key list, and reference new one */
872 kfree(md5sig->keys4);
873 md5sig->keys4 = keys;
874 md5sig->alloced4++;
875 }
876 md5sig->entries4++;
877 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
878 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
879 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
880 }
881 return 0;
882 }
883
884 EXPORT_SYMBOL(tcp_v4_md5_do_add);
885
886 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
887 u8 *newkey, u8 newkeylen)
888 {
889 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
890 newkey, newkeylen);
891 }
892
893 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
894 {
895 struct tcp_sock *tp = tcp_sk(sk);
896 int i;
897
898 for (i = 0; i < tp->md5sig_info->entries4; i++) {
899 if (tp->md5sig_info->keys4[i].addr == addr) {
900 /* Free the key */
901 kfree(tp->md5sig_info->keys4[i].base.key);
902 tp->md5sig_info->entries4--;
903
904 if (tp->md5sig_info->entries4 == 0) {
905 kfree(tp->md5sig_info->keys4);
906 tp->md5sig_info->keys4 = NULL;
907 tp->md5sig_info->alloced4 = 0;
908 } else if (tp->md5sig_info->entries4 != i) {
909 /* Need to do some manipulation */
910 memmove(&tp->md5sig_info->keys4[i],
911 &tp->md5sig_info->keys4[i+1],
912 (tp->md5sig_info->entries4 - i) *
913 sizeof(struct tcp4_md5sig_key));
914 }
915 tcp_free_md5sig_pool();
916 return 0;
917 }
918 }
919 return -ENOENT;
920 }
921
922 EXPORT_SYMBOL(tcp_v4_md5_do_del);
923
924 static void tcp_v4_clear_md5_list(struct sock *sk)
925 {
926 struct tcp_sock *tp = tcp_sk(sk);
927
928 /* Free each key, then the set of key keys,
929 * the crypto element, and then decrement our
930 * hold on the last resort crypto.
931 */
932 if (tp->md5sig_info->entries4) {
933 int i;
934 for (i = 0; i < tp->md5sig_info->entries4; i++)
935 kfree(tp->md5sig_info->keys4[i].base.key);
936 tp->md5sig_info->entries4 = 0;
937 tcp_free_md5sig_pool();
938 }
939 if (tp->md5sig_info->keys4) {
940 kfree(tp->md5sig_info->keys4);
941 tp->md5sig_info->keys4 = NULL;
942 tp->md5sig_info->alloced4 = 0;
943 }
944 }
945
946 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
947 int optlen)
948 {
949 struct tcp_md5sig cmd;
950 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
951 u8 *newkey;
952
953 if (optlen < sizeof(cmd))
954 return -EINVAL;
955
956 if (copy_from_user(&cmd, optval, sizeof(cmd)))
957 return -EFAULT;
958
959 if (sin->sin_family != AF_INET)
960 return -EINVAL;
961
962 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
963 if (!tcp_sk(sk)->md5sig_info)
964 return -ENOENT;
965 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
966 }
967
968 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
969 return -EINVAL;
970
971 if (!tcp_sk(sk)->md5sig_info) {
972 struct tcp_sock *tp = tcp_sk(sk);
973 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
974
975 if (!p)
976 return -EINVAL;
977
978 tp->md5sig_info = p;
979 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
980 }
981
982 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
983 if (!newkey)
984 return -ENOMEM;
985 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
986 newkey, cmd.tcpm_keylen);
987 }
988
989 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
990 __be32 daddr, __be32 saddr, int nbytes)
991 {
992 struct tcp4_pseudohdr *bp;
993 struct scatterlist sg;
994
995 bp = &hp->md5_blk.ip4;
996
997 /*
998 * 1. the TCP pseudo-header (in the order: source IP address,
999 * destination IP address, zero-padded protocol number, and
1000 * segment length)
1001 */
1002 bp->saddr = saddr;
1003 bp->daddr = daddr;
1004 bp->pad = 0;
1005 bp->protocol = IPPROTO_TCP;
1006 bp->len = cpu_to_be16(nbytes);
1007
1008 sg_init_one(&sg, bp, sizeof(*bp));
1009 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1010 }
1011
1012 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1013 __be32 daddr, __be32 saddr, struct tcphdr *th)
1014 {
1015 struct tcp_md5sig_pool *hp;
1016 struct hash_desc *desc;
1017
1018 hp = tcp_get_md5sig_pool();
1019 if (!hp)
1020 goto clear_hash_noput;
1021 desc = &hp->md5_desc;
1022
1023 if (crypto_hash_init(desc))
1024 goto clear_hash;
1025 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1026 goto clear_hash;
1027 if (tcp_md5_hash_header(hp, th))
1028 goto clear_hash;
1029 if (tcp_md5_hash_key(hp, key))
1030 goto clear_hash;
1031 if (crypto_hash_final(desc, md5_hash))
1032 goto clear_hash;
1033
1034 tcp_put_md5sig_pool();
1035 return 0;
1036
1037 clear_hash:
1038 tcp_put_md5sig_pool();
1039 clear_hash_noput:
1040 memset(md5_hash, 0, 16);
1041 return 1;
1042 }
1043
1044 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1045 struct sock *sk, struct request_sock *req,
1046 struct sk_buff *skb)
1047 {
1048 struct tcp_md5sig_pool *hp;
1049 struct hash_desc *desc;
1050 struct tcphdr *th = tcp_hdr(skb);
1051 __be32 saddr, daddr;
1052
1053 if (sk) {
1054 saddr = inet_sk(sk)->saddr;
1055 daddr = inet_sk(sk)->daddr;
1056 } else if (req) {
1057 saddr = inet_rsk(req)->loc_addr;
1058 daddr = inet_rsk(req)->rmt_addr;
1059 } else {
1060 const struct iphdr *iph = ip_hdr(skb);
1061 saddr = iph->saddr;
1062 daddr = iph->daddr;
1063 }
1064
1065 hp = tcp_get_md5sig_pool();
1066 if (!hp)
1067 goto clear_hash_noput;
1068 desc = &hp->md5_desc;
1069
1070 if (crypto_hash_init(desc))
1071 goto clear_hash;
1072
1073 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1074 goto clear_hash;
1075 if (tcp_md5_hash_header(hp, th))
1076 goto clear_hash;
1077 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1078 goto clear_hash;
1079 if (tcp_md5_hash_key(hp, key))
1080 goto clear_hash;
1081 if (crypto_hash_final(desc, md5_hash))
1082 goto clear_hash;
1083
1084 tcp_put_md5sig_pool();
1085 return 0;
1086
1087 clear_hash:
1088 tcp_put_md5sig_pool();
1089 clear_hash_noput:
1090 memset(md5_hash, 0, 16);
1091 return 1;
1092 }
1093
1094 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1095
1096 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1097 {
1098 /*
1099 * This gets called for each TCP segment that arrives
1100 * so we want to be efficient.
1101 * We have 3 drop cases:
1102 * o No MD5 hash and one expected.
1103 * o MD5 hash and we're not expecting one.
1104 * o MD5 hash and its wrong.
1105 */
1106 __u8 *hash_location = NULL;
1107 struct tcp_md5sig_key *hash_expected;
1108 const struct iphdr *iph = ip_hdr(skb);
1109 struct tcphdr *th = tcp_hdr(skb);
1110 int genhash;
1111 unsigned char newhash[16];
1112
1113 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1114 hash_location = tcp_parse_md5sig_option(th);
1115
1116 /* We've parsed the options - do we have a hash? */
1117 if (!hash_expected && !hash_location)
1118 return 0;
1119
1120 if (hash_expected && !hash_location) {
1121 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1122 return 1;
1123 }
1124
1125 if (!hash_expected && hash_location) {
1126 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1127 return 1;
1128 }
1129
1130 /* Okay, so this is hash_expected and hash_location -
1131 * so we need to calculate the checksum.
1132 */
1133 genhash = tcp_v4_md5_hash_skb(newhash,
1134 hash_expected,
1135 NULL, NULL, skb);
1136
1137 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1138 if (net_ratelimit()) {
1139 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1140 &iph->saddr, ntohs(th->source),
1141 &iph->daddr, ntohs(th->dest),
1142 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1143 }
1144 return 1;
1145 }
1146 return 0;
1147 }
1148
1149 #endif
1150
1151 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1152 .family = PF_INET,
1153 .obj_size = sizeof(struct tcp_request_sock),
1154 .rtx_syn_ack = tcp_v4_send_synack,
1155 .send_ack = tcp_v4_reqsk_send_ack,
1156 .destructor = tcp_v4_reqsk_destructor,
1157 .send_reset = tcp_v4_send_reset,
1158 };
1159
1160 #ifdef CONFIG_TCP_MD5SIG
1161 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1162 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1163 };
1164 #endif
1165
1166 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1167 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1168 .twsk_unique = tcp_twsk_unique,
1169 .twsk_destructor= tcp_twsk_destructor,
1170 };
1171
1172 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1173 {
1174 struct inet_request_sock *ireq;
1175 struct tcp_options_received tmp_opt;
1176 struct request_sock *req;
1177 __be32 saddr = ip_hdr(skb)->saddr;
1178 __be32 daddr = ip_hdr(skb)->daddr;
1179 __u32 isn = TCP_SKB_CB(skb)->when;
1180 struct dst_entry *dst = NULL;
1181 #ifdef CONFIG_SYN_COOKIES
1182 int want_cookie = 0;
1183 #else
1184 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1185 #endif
1186
1187 /* Never answer to SYNs send to broadcast or multicast */
1188 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1189 goto drop;
1190
1191 /* TW buckets are converted to open requests without
1192 * limitations, they conserve resources and peer is
1193 * evidently real one.
1194 */
1195 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1196 #ifdef CONFIG_SYN_COOKIES
1197 if (sysctl_tcp_syncookies) {
1198 want_cookie = 1;
1199 } else
1200 #endif
1201 goto drop;
1202 }
1203
1204 /* Accept backlog is full. If we have already queued enough
1205 * of warm entries in syn queue, drop request. It is better than
1206 * clogging syn queue with openreqs with exponentially increasing
1207 * timeout.
1208 */
1209 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1210 goto drop;
1211
1212 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1213 if (!req)
1214 goto drop;
1215
1216 #ifdef CONFIG_TCP_MD5SIG
1217 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1218 #endif
1219
1220 tcp_clear_options(&tmp_opt);
1221 tmp_opt.mss_clamp = 536;
1222 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1223
1224 tcp_parse_options(skb, &tmp_opt, 0);
1225
1226 if (want_cookie && !tmp_opt.saw_tstamp)
1227 tcp_clear_options(&tmp_opt);
1228
1229 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1230 /* Some OSes (unknown ones, but I see them on web server, which
1231 * contains information interesting only for windows'
1232 * users) do not send their stamp in SYN. It is easy case.
1233 * We simply do not advertise TS support.
1234 */
1235 tmp_opt.saw_tstamp = 0;
1236 tmp_opt.tstamp_ok = 0;
1237 }
1238 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1239
1240 tcp_openreq_init(req, &tmp_opt, skb);
1241
1242 ireq = inet_rsk(req);
1243 ireq->loc_addr = daddr;
1244 ireq->rmt_addr = saddr;
1245 ireq->no_srccheck = inet_sk(sk)->transparent;
1246 ireq->opt = tcp_v4_save_options(sk, skb);
1247
1248 if (security_inet_conn_request(sk, skb, req))
1249 goto drop_and_free;
1250
1251 if (!want_cookie)
1252 TCP_ECN_create_request(req, tcp_hdr(skb));
1253
1254 if (want_cookie) {
1255 #ifdef CONFIG_SYN_COOKIES
1256 syn_flood_warning(skb);
1257 req->cookie_ts = tmp_opt.tstamp_ok;
1258 #endif
1259 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1260 } else if (!isn) {
1261 struct inet_peer *peer = NULL;
1262
1263 /* VJ's idea. We save last timestamp seen
1264 * from the destination in peer table, when entering
1265 * state TIME-WAIT, and check against it before
1266 * accepting new connection request.
1267 *
1268 * If "isn" is not zero, this request hit alive
1269 * timewait bucket, so that all the necessary checks
1270 * are made in the function processing timewait state.
1271 */
1272 if (tmp_opt.saw_tstamp &&
1273 tcp_death_row.sysctl_tw_recycle &&
1274 (dst = inet_csk_route_req(sk, req)) != NULL &&
1275 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1276 peer->v4daddr == saddr) {
1277 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1278 (s32)(peer->tcp_ts - req->ts_recent) >
1279 TCP_PAWS_WINDOW) {
1280 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1281 goto drop_and_release;
1282 }
1283 }
1284 /* Kill the following clause, if you dislike this way. */
1285 else if (!sysctl_tcp_syncookies &&
1286 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1287 (sysctl_max_syn_backlog >> 2)) &&
1288 (!peer || !peer->tcp_ts_stamp) &&
1289 (!dst || !dst_metric(dst, RTAX_RTT))) {
1290 /* Without syncookies last quarter of
1291 * backlog is filled with destinations,
1292 * proven to be alive.
1293 * It means that we continue to communicate
1294 * to destinations, already remembered
1295 * to the moment of synflood.
1296 */
1297 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1298 &saddr, ntohs(tcp_hdr(skb)->source));
1299 goto drop_and_release;
1300 }
1301
1302 isn = tcp_v4_init_sequence(skb);
1303 }
1304 tcp_rsk(req)->snt_isn = isn;
1305
1306 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1307 goto drop_and_free;
1308
1309 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1310 return 0;
1311
1312 drop_and_release:
1313 dst_release(dst);
1314 drop_and_free:
1315 reqsk_free(req);
1316 drop:
1317 return 0;
1318 }
1319
1320
1321 /*
1322 * The three way handshake has completed - we got a valid synack -
1323 * now create the new socket.
1324 */
1325 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1326 struct request_sock *req,
1327 struct dst_entry *dst)
1328 {
1329 struct inet_request_sock *ireq;
1330 struct inet_sock *newinet;
1331 struct tcp_sock *newtp;
1332 struct sock *newsk;
1333 #ifdef CONFIG_TCP_MD5SIG
1334 struct tcp_md5sig_key *key;
1335 #endif
1336
1337 if (sk_acceptq_is_full(sk))
1338 goto exit_overflow;
1339
1340 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1341 goto exit;
1342
1343 newsk = tcp_create_openreq_child(sk, req, skb);
1344 if (!newsk)
1345 goto exit;
1346
1347 newsk->sk_gso_type = SKB_GSO_TCPV4;
1348 sk_setup_caps(newsk, dst);
1349
1350 newtp = tcp_sk(newsk);
1351 newinet = inet_sk(newsk);
1352 ireq = inet_rsk(req);
1353 newinet->daddr = ireq->rmt_addr;
1354 newinet->rcv_saddr = ireq->loc_addr;
1355 newinet->saddr = ireq->loc_addr;
1356 newinet->opt = ireq->opt;
1357 ireq->opt = NULL;
1358 newinet->mc_index = inet_iif(skb);
1359 newinet->mc_ttl = ip_hdr(skb)->ttl;
1360 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1361 if (newinet->opt)
1362 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1363 newinet->id = newtp->write_seq ^ jiffies;
1364
1365 tcp_mtup_init(newsk);
1366 tcp_sync_mss(newsk, dst_mtu(dst));
1367 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1368 if (tcp_sk(sk)->rx_opt.user_mss &&
1369 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1370 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1371
1372 tcp_initialize_rcv_mss(newsk);
1373
1374 #ifdef CONFIG_TCP_MD5SIG
1375 /* Copy over the MD5 key from the original socket */
1376 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1377 /*
1378 * We're using one, so create a matching key
1379 * on the newsk structure. If we fail to get
1380 * memory, then we end up not copying the key
1381 * across. Shucks.
1382 */
1383 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1384 if (newkey != NULL)
1385 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1386 newkey, key->keylen);
1387 newsk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1388 }
1389 #endif
1390
1391 __inet_hash_nolisten(newsk);
1392 __inet_inherit_port(sk, newsk);
1393
1394 return newsk;
1395
1396 exit_overflow:
1397 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1398 exit:
1399 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1400 dst_release(dst);
1401 return NULL;
1402 }
1403
1404 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1405 {
1406 struct tcphdr *th = tcp_hdr(skb);
1407 const struct iphdr *iph = ip_hdr(skb);
1408 struct sock *nsk;
1409 struct request_sock **prev;
1410 /* Find possible connection requests. */
1411 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1412 iph->saddr, iph->daddr);
1413 if (req)
1414 return tcp_check_req(sk, skb, req, prev);
1415
1416 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1417 th->source, iph->daddr, th->dest, inet_iif(skb));
1418
1419 if (nsk) {
1420 if (nsk->sk_state != TCP_TIME_WAIT) {
1421 bh_lock_sock(nsk);
1422 return nsk;
1423 }
1424 inet_twsk_put(inet_twsk(nsk));
1425 return NULL;
1426 }
1427
1428 #ifdef CONFIG_SYN_COOKIES
1429 if (!th->rst && !th->syn && th->ack)
1430 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1431 #endif
1432 return sk;
1433 }
1434
1435 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1436 {
1437 const struct iphdr *iph = ip_hdr(skb);
1438
1439 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1440 if (!tcp_v4_check(skb->len, iph->saddr,
1441 iph->daddr, skb->csum)) {
1442 skb->ip_summed = CHECKSUM_UNNECESSARY;
1443 return 0;
1444 }
1445 }
1446
1447 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1448 skb->len, IPPROTO_TCP, 0);
1449
1450 if (skb->len <= 76) {
1451 return __skb_checksum_complete(skb);
1452 }
1453 return 0;
1454 }
1455
1456
1457 /* The socket must have it's spinlock held when we get
1458 * here.
1459 *
1460 * We have a potential double-lock case here, so even when
1461 * doing backlog processing we use the BH locking scheme.
1462 * This is because we cannot sleep with the original spinlock
1463 * held.
1464 */
1465 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1466 {
1467 struct sock *rsk;
1468 #ifdef CONFIG_TCP_MD5SIG
1469 /*
1470 * We really want to reject the packet as early as possible
1471 * if:
1472 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1473 * o There is an MD5 option and we're not expecting one
1474 */
1475 if (tcp_v4_inbound_md5_hash(sk, skb))
1476 goto discard;
1477 #endif
1478
1479 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1480 TCP_CHECK_TIMER(sk);
1481 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1482 rsk = sk;
1483 goto reset;
1484 }
1485 TCP_CHECK_TIMER(sk);
1486 return 0;
1487 }
1488
1489 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1490 goto csum_err;
1491
1492 if (sk->sk_state == TCP_LISTEN) {
1493 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1494 if (!nsk)
1495 goto discard;
1496
1497 if (nsk != sk) {
1498 if (tcp_child_process(sk, nsk, skb)) {
1499 rsk = nsk;
1500 goto reset;
1501 }
1502 return 0;
1503 }
1504 }
1505
1506 TCP_CHECK_TIMER(sk);
1507 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1508 rsk = sk;
1509 goto reset;
1510 }
1511 TCP_CHECK_TIMER(sk);
1512 return 0;
1513
1514 reset:
1515 tcp_v4_send_reset(rsk, skb);
1516 discard:
1517 kfree_skb(skb);
1518 /* Be careful here. If this function gets more complicated and
1519 * gcc suffers from register pressure on the x86, sk (in %ebx)
1520 * might be destroyed here. This current version compiles correctly,
1521 * but you have been warned.
1522 */
1523 return 0;
1524
1525 csum_err:
1526 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1527 goto discard;
1528 }
1529
1530 /*
1531 * From tcp_input.c
1532 */
1533
1534 int tcp_v4_rcv(struct sk_buff *skb)
1535 {
1536 const struct iphdr *iph;
1537 struct tcphdr *th;
1538 struct sock *sk;
1539 int ret;
1540 struct net *net = dev_net(skb->dev);
1541
1542 if (skb->pkt_type != PACKET_HOST)
1543 goto discard_it;
1544
1545 /* Count it even if it's bad */
1546 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1547
1548 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1549 goto discard_it;
1550
1551 th = tcp_hdr(skb);
1552
1553 if (th->doff < sizeof(struct tcphdr) / 4)
1554 goto bad_packet;
1555 if (!pskb_may_pull(skb, th->doff * 4))
1556 goto discard_it;
1557
1558 /* An explanation is required here, I think.
1559 * Packet length and doff are validated by header prediction,
1560 * provided case of th->doff==0 is eliminated.
1561 * So, we defer the checks. */
1562 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1563 goto bad_packet;
1564
1565 th = tcp_hdr(skb);
1566 iph = ip_hdr(skb);
1567 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1568 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1569 skb->len - th->doff * 4);
1570 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1571 TCP_SKB_CB(skb)->when = 0;
1572 TCP_SKB_CB(skb)->flags = iph->tos;
1573 TCP_SKB_CB(skb)->sacked = 0;
1574
1575 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1576 if (!sk)
1577 goto no_tcp_socket;
1578
1579 process:
1580 if (sk->sk_state == TCP_TIME_WAIT)
1581 goto do_time_wait;
1582
1583 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1584 goto discard_and_relse;
1585 nf_reset(skb);
1586
1587 if (sk_filter(sk, skb))
1588 goto discard_and_relse;
1589
1590 skb->dev = NULL;
1591
1592 bh_lock_sock_nested(sk);
1593 ret = 0;
1594 if (!sock_owned_by_user(sk)) {
1595 #ifdef CONFIG_NET_DMA
1596 struct tcp_sock *tp = tcp_sk(sk);
1597 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1598 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1599 if (tp->ucopy.dma_chan)
1600 ret = tcp_v4_do_rcv(sk, skb);
1601 else
1602 #endif
1603 {
1604 if (!tcp_prequeue(sk, skb))
1605 ret = tcp_v4_do_rcv(sk, skb);
1606 }
1607 } else
1608 sk_add_backlog(sk, skb);
1609 bh_unlock_sock(sk);
1610
1611 sock_put(sk);
1612
1613 return ret;
1614
1615 no_tcp_socket:
1616 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1617 goto discard_it;
1618
1619 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1620 bad_packet:
1621 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1622 } else {
1623 tcp_v4_send_reset(NULL, skb);
1624 }
1625
1626 discard_it:
1627 /* Discard frame. */
1628 kfree_skb(skb);
1629 return 0;
1630
1631 discard_and_relse:
1632 sock_put(sk);
1633 goto discard_it;
1634
1635 do_time_wait:
1636 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1637 inet_twsk_put(inet_twsk(sk));
1638 goto discard_it;
1639 }
1640
1641 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1642 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1643 inet_twsk_put(inet_twsk(sk));
1644 goto discard_it;
1645 }
1646 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1647 case TCP_TW_SYN: {
1648 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1649 &tcp_hashinfo,
1650 iph->daddr, th->dest,
1651 inet_iif(skb));
1652 if (sk2) {
1653 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1654 inet_twsk_put(inet_twsk(sk));
1655 sk = sk2;
1656 goto process;
1657 }
1658 /* Fall through to ACK */
1659 }
1660 case TCP_TW_ACK:
1661 tcp_v4_timewait_ack(sk, skb);
1662 break;
1663 case TCP_TW_RST:
1664 goto no_tcp_socket;
1665 case TCP_TW_SUCCESS:;
1666 }
1667 goto discard_it;
1668 }
1669
1670 /* VJ's idea. Save last timestamp seen from this destination
1671 * and hold it at least for normal timewait interval to use for duplicate
1672 * segment detection in subsequent connections, before they enter synchronized
1673 * state.
1674 */
1675
1676 int tcp_v4_remember_stamp(struct sock *sk)
1677 {
1678 struct inet_sock *inet = inet_sk(sk);
1679 struct tcp_sock *tp = tcp_sk(sk);
1680 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1681 struct inet_peer *peer = NULL;
1682 int release_it = 0;
1683
1684 if (!rt || rt->rt_dst != inet->daddr) {
1685 peer = inet_getpeer(inet->daddr, 1);
1686 release_it = 1;
1687 } else {
1688 if (!rt->peer)
1689 rt_bind_peer(rt, 1);
1690 peer = rt->peer;
1691 }
1692
1693 if (peer) {
1694 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1695 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1696 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1697 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1698 peer->tcp_ts = tp->rx_opt.ts_recent;
1699 }
1700 if (release_it)
1701 inet_putpeer(peer);
1702 return 1;
1703 }
1704
1705 return 0;
1706 }
1707
1708 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1709 {
1710 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1711
1712 if (peer) {
1713 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1714
1715 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1716 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1717 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1718 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1719 peer->tcp_ts = tcptw->tw_ts_recent;
1720 }
1721 inet_putpeer(peer);
1722 return 1;
1723 }
1724
1725 return 0;
1726 }
1727
1728 struct inet_connection_sock_af_ops ipv4_specific = {
1729 .queue_xmit = ip_queue_xmit,
1730 .send_check = tcp_v4_send_check,
1731 .rebuild_header = inet_sk_rebuild_header,
1732 .conn_request = tcp_v4_conn_request,
1733 .syn_recv_sock = tcp_v4_syn_recv_sock,
1734 .remember_stamp = tcp_v4_remember_stamp,
1735 .net_header_len = sizeof(struct iphdr),
1736 .setsockopt = ip_setsockopt,
1737 .getsockopt = ip_getsockopt,
1738 .addr2sockaddr = inet_csk_addr2sockaddr,
1739 .sockaddr_len = sizeof(struct sockaddr_in),
1740 .bind_conflict = inet_csk_bind_conflict,
1741 #ifdef CONFIG_COMPAT
1742 .compat_setsockopt = compat_ip_setsockopt,
1743 .compat_getsockopt = compat_ip_getsockopt,
1744 #endif
1745 };
1746
1747 #ifdef CONFIG_TCP_MD5SIG
1748 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1749 .md5_lookup = tcp_v4_md5_lookup,
1750 .calc_md5_hash = tcp_v4_md5_hash_skb,
1751 .md5_add = tcp_v4_md5_add_func,
1752 .md5_parse = tcp_v4_parse_md5_keys,
1753 };
1754 #endif
1755
1756 /* NOTE: A lot of things set to zero explicitly by call to
1757 * sk_alloc() so need not be done here.
1758 */
1759 static int tcp_v4_init_sock(struct sock *sk)
1760 {
1761 struct inet_connection_sock *icsk = inet_csk(sk);
1762 struct tcp_sock *tp = tcp_sk(sk);
1763
1764 skb_queue_head_init(&tp->out_of_order_queue);
1765 tcp_init_xmit_timers(sk);
1766 tcp_prequeue_init(tp);
1767
1768 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1769 tp->mdev = TCP_TIMEOUT_INIT;
1770
1771 /* So many TCP implementations out there (incorrectly) count the
1772 * initial SYN frame in their delayed-ACK and congestion control
1773 * algorithms that we must have the following bandaid to talk
1774 * efficiently to them. -DaveM
1775 */
1776 tp->snd_cwnd = 2;
1777
1778 /* See draft-stevens-tcpca-spec-01 for discussion of the
1779 * initialization of these values.
1780 */
1781 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1782 tp->snd_cwnd_clamp = ~0;
1783 tp->mss_cache = 536;
1784
1785 tp->reordering = sysctl_tcp_reordering;
1786 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1787
1788 sk->sk_state = TCP_CLOSE;
1789
1790 sk->sk_write_space = sk_stream_write_space;
1791 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1792
1793 icsk->icsk_af_ops = &ipv4_specific;
1794 icsk->icsk_sync_mss = tcp_sync_mss;
1795 #ifdef CONFIG_TCP_MD5SIG
1796 tp->af_specific = &tcp_sock_ipv4_specific;
1797 #endif
1798
1799 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1800 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1801
1802 local_bh_disable();
1803 percpu_counter_inc(&tcp_sockets_allocated);
1804 local_bh_enable();
1805
1806 return 0;
1807 }
1808
1809 void tcp_v4_destroy_sock(struct sock *sk)
1810 {
1811 struct tcp_sock *tp = tcp_sk(sk);
1812
1813 tcp_clear_xmit_timers(sk);
1814
1815 tcp_cleanup_congestion_control(sk);
1816
1817 /* Cleanup up the write buffer. */
1818 tcp_write_queue_purge(sk);
1819
1820 /* Cleans up our, hopefully empty, out_of_order_queue. */
1821 __skb_queue_purge(&tp->out_of_order_queue);
1822
1823 #ifdef CONFIG_TCP_MD5SIG
1824 /* Clean up the MD5 key list, if any */
1825 if (tp->md5sig_info) {
1826 tcp_v4_clear_md5_list(sk);
1827 kfree(tp->md5sig_info);
1828 tp->md5sig_info = NULL;
1829 }
1830 #endif
1831
1832 #ifdef CONFIG_NET_DMA
1833 /* Cleans up our sk_async_wait_queue */
1834 __skb_queue_purge(&sk->sk_async_wait_queue);
1835 #endif
1836
1837 /* Clean prequeue, it must be empty really */
1838 __skb_queue_purge(&tp->ucopy.prequeue);
1839
1840 /* Clean up a referenced TCP bind bucket. */
1841 if (inet_csk(sk)->icsk_bind_hash)
1842 inet_put_port(sk);
1843
1844 /*
1845 * If sendmsg cached page exists, toss it.
1846 */
1847 if (sk->sk_sndmsg_page) {
1848 __free_page(sk->sk_sndmsg_page);
1849 sk->sk_sndmsg_page = NULL;
1850 }
1851
1852 percpu_counter_dec(&tcp_sockets_allocated);
1853 }
1854
1855 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1856
1857 #ifdef CONFIG_PROC_FS
1858 /* Proc filesystem TCP sock list dumping. */
1859
1860 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1861 {
1862 return hlist_nulls_empty(head) ? NULL :
1863 list_entry(head->first, struct inet_timewait_sock, tw_node);
1864 }
1865
1866 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1867 {
1868 return !is_a_nulls(tw->tw_node.next) ?
1869 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1870 }
1871
1872 static void *listening_get_next(struct seq_file *seq, void *cur)
1873 {
1874 struct inet_connection_sock *icsk;
1875 struct hlist_nulls_node *node;
1876 struct sock *sk = cur;
1877 struct inet_listen_hashbucket *ilb;
1878 struct tcp_iter_state *st = seq->private;
1879 struct net *net = seq_file_net(seq);
1880
1881 if (!sk) {
1882 st->bucket = 0;
1883 ilb = &tcp_hashinfo.listening_hash[0];
1884 spin_lock_bh(&ilb->lock);
1885 sk = sk_nulls_head(&ilb->head);
1886 goto get_sk;
1887 }
1888 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1889 ++st->num;
1890
1891 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1892 struct request_sock *req = cur;
1893
1894 icsk = inet_csk(st->syn_wait_sk);
1895 req = req->dl_next;
1896 while (1) {
1897 while (req) {
1898 if (req->rsk_ops->family == st->family) {
1899 cur = req;
1900 goto out;
1901 }
1902 req = req->dl_next;
1903 }
1904 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1905 break;
1906 get_req:
1907 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1908 }
1909 sk = sk_next(st->syn_wait_sk);
1910 st->state = TCP_SEQ_STATE_LISTENING;
1911 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1912 } else {
1913 icsk = inet_csk(sk);
1914 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1915 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1916 goto start_req;
1917 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1918 sk = sk_next(sk);
1919 }
1920 get_sk:
1921 sk_nulls_for_each_from(sk, node) {
1922 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
1923 cur = sk;
1924 goto out;
1925 }
1926 icsk = inet_csk(sk);
1927 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1928 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1929 start_req:
1930 st->uid = sock_i_uid(sk);
1931 st->syn_wait_sk = sk;
1932 st->state = TCP_SEQ_STATE_OPENREQ;
1933 st->sbucket = 0;
1934 goto get_req;
1935 }
1936 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1937 }
1938 spin_unlock_bh(&ilb->lock);
1939 if (++st->bucket < INET_LHTABLE_SIZE) {
1940 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1941 spin_lock_bh(&ilb->lock);
1942 sk = sk_nulls_head(&ilb->head);
1943 goto get_sk;
1944 }
1945 cur = NULL;
1946 out:
1947 return cur;
1948 }
1949
1950 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1951 {
1952 void *rc = listening_get_next(seq, NULL);
1953
1954 while (rc && *pos) {
1955 rc = listening_get_next(seq, rc);
1956 --*pos;
1957 }
1958 return rc;
1959 }
1960
1961 static inline int empty_bucket(struct tcp_iter_state *st)
1962 {
1963 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
1964 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
1965 }
1966
1967 static void *established_get_first(struct seq_file *seq)
1968 {
1969 struct tcp_iter_state *st = seq->private;
1970 struct net *net = seq_file_net(seq);
1971 void *rc = NULL;
1972
1973 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
1974 struct sock *sk;
1975 struct hlist_nulls_node *node;
1976 struct inet_timewait_sock *tw;
1977 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1978
1979 /* Lockless fast path for the common case of empty buckets */
1980 if (empty_bucket(st))
1981 continue;
1982
1983 spin_lock_bh(lock);
1984 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1985 if (sk->sk_family != st->family ||
1986 !net_eq(sock_net(sk), net)) {
1987 continue;
1988 }
1989 rc = sk;
1990 goto out;
1991 }
1992 st->state = TCP_SEQ_STATE_TIME_WAIT;
1993 inet_twsk_for_each(tw, node,
1994 &tcp_hashinfo.ehash[st->bucket].twchain) {
1995 if (tw->tw_family != st->family ||
1996 !net_eq(twsk_net(tw), net)) {
1997 continue;
1998 }
1999 rc = tw;
2000 goto out;
2001 }
2002 spin_unlock_bh(lock);
2003 st->state = TCP_SEQ_STATE_ESTABLISHED;
2004 }
2005 out:
2006 return rc;
2007 }
2008
2009 static void *established_get_next(struct seq_file *seq, void *cur)
2010 {
2011 struct sock *sk = cur;
2012 struct inet_timewait_sock *tw;
2013 struct hlist_nulls_node *node;
2014 struct tcp_iter_state *st = seq->private;
2015 struct net *net = seq_file_net(seq);
2016
2017 ++st->num;
2018
2019 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2020 tw = cur;
2021 tw = tw_next(tw);
2022 get_tw:
2023 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2024 tw = tw_next(tw);
2025 }
2026 if (tw) {
2027 cur = tw;
2028 goto out;
2029 }
2030 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2031 st->state = TCP_SEQ_STATE_ESTABLISHED;
2032
2033 /* Look for next non empty bucket */
2034 while (++st->bucket < tcp_hashinfo.ehash_size &&
2035 empty_bucket(st))
2036 ;
2037 if (st->bucket >= tcp_hashinfo.ehash_size)
2038 return NULL;
2039
2040 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2041 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2042 } else
2043 sk = sk_nulls_next(sk);
2044
2045 sk_nulls_for_each_from(sk, node) {
2046 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2047 goto found;
2048 }
2049
2050 st->state = TCP_SEQ_STATE_TIME_WAIT;
2051 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2052 goto get_tw;
2053 found:
2054 cur = sk;
2055 out:
2056 return cur;
2057 }
2058
2059 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2060 {
2061 void *rc = established_get_first(seq);
2062
2063 while (rc && pos) {
2064 rc = established_get_next(seq, rc);
2065 --pos;
2066 }
2067 return rc;
2068 }
2069
2070 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2071 {
2072 void *rc;
2073 struct tcp_iter_state *st = seq->private;
2074
2075 st->state = TCP_SEQ_STATE_LISTENING;
2076 rc = listening_get_idx(seq, &pos);
2077
2078 if (!rc) {
2079 st->state = TCP_SEQ_STATE_ESTABLISHED;
2080 rc = established_get_idx(seq, pos);
2081 }
2082
2083 return rc;
2084 }
2085
2086 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2087 {
2088 struct tcp_iter_state *st = seq->private;
2089 st->state = TCP_SEQ_STATE_LISTENING;
2090 st->num = 0;
2091 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2092 }
2093
2094 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2095 {
2096 void *rc = NULL;
2097 struct tcp_iter_state *st;
2098
2099 if (v == SEQ_START_TOKEN) {
2100 rc = tcp_get_idx(seq, 0);
2101 goto out;
2102 }
2103 st = seq->private;
2104
2105 switch (st->state) {
2106 case TCP_SEQ_STATE_OPENREQ:
2107 case TCP_SEQ_STATE_LISTENING:
2108 rc = listening_get_next(seq, v);
2109 if (!rc) {
2110 st->state = TCP_SEQ_STATE_ESTABLISHED;
2111 rc = established_get_first(seq);
2112 }
2113 break;
2114 case TCP_SEQ_STATE_ESTABLISHED:
2115 case TCP_SEQ_STATE_TIME_WAIT:
2116 rc = established_get_next(seq, v);
2117 break;
2118 }
2119 out:
2120 ++*pos;
2121 return rc;
2122 }
2123
2124 static void tcp_seq_stop(struct seq_file *seq, void *v)
2125 {
2126 struct tcp_iter_state *st = seq->private;
2127
2128 switch (st->state) {
2129 case TCP_SEQ_STATE_OPENREQ:
2130 if (v) {
2131 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2132 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2133 }
2134 case TCP_SEQ_STATE_LISTENING:
2135 if (v != SEQ_START_TOKEN)
2136 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2137 break;
2138 case TCP_SEQ_STATE_TIME_WAIT:
2139 case TCP_SEQ_STATE_ESTABLISHED:
2140 if (v)
2141 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2142 break;
2143 }
2144 }
2145
2146 static int tcp_seq_open(struct inode *inode, struct file *file)
2147 {
2148 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2149 struct tcp_iter_state *s;
2150 int err;
2151
2152 err = seq_open_net(inode, file, &afinfo->seq_ops,
2153 sizeof(struct tcp_iter_state));
2154 if (err < 0)
2155 return err;
2156
2157 s = ((struct seq_file *)file->private_data)->private;
2158 s->family = afinfo->family;
2159 return 0;
2160 }
2161
2162 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2163 {
2164 int rc = 0;
2165 struct proc_dir_entry *p;
2166
2167 afinfo->seq_fops.open = tcp_seq_open;
2168 afinfo->seq_fops.read = seq_read;
2169 afinfo->seq_fops.llseek = seq_lseek;
2170 afinfo->seq_fops.release = seq_release_net;
2171
2172 afinfo->seq_ops.start = tcp_seq_start;
2173 afinfo->seq_ops.next = tcp_seq_next;
2174 afinfo->seq_ops.stop = tcp_seq_stop;
2175
2176 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2177 &afinfo->seq_fops, afinfo);
2178 if (!p)
2179 rc = -ENOMEM;
2180 return rc;
2181 }
2182
2183 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2184 {
2185 proc_net_remove(net, afinfo->name);
2186 }
2187
2188 static void get_openreq4(struct sock *sk, struct request_sock *req,
2189 struct seq_file *f, int i, int uid, int *len)
2190 {
2191 const struct inet_request_sock *ireq = inet_rsk(req);
2192 int ttd = req->expires - jiffies;
2193
2194 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2195 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2196 i,
2197 ireq->loc_addr,
2198 ntohs(inet_sk(sk)->sport),
2199 ireq->rmt_addr,
2200 ntohs(ireq->rmt_port),
2201 TCP_SYN_RECV,
2202 0, 0, /* could print option size, but that is af dependent. */
2203 1, /* timers active (only the expire timer) */
2204 jiffies_to_clock_t(ttd),
2205 req->retrans,
2206 uid,
2207 0, /* non standard timer */
2208 0, /* open_requests have no inode */
2209 atomic_read(&sk->sk_refcnt),
2210 req,
2211 len);
2212 }
2213
2214 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2215 {
2216 int timer_active;
2217 unsigned long timer_expires;
2218 struct tcp_sock *tp = tcp_sk(sk);
2219 const struct inet_connection_sock *icsk = inet_csk(sk);
2220 struct inet_sock *inet = inet_sk(sk);
2221 __be32 dest = inet->daddr;
2222 __be32 src = inet->rcv_saddr;
2223 __u16 destp = ntohs(inet->dport);
2224 __u16 srcp = ntohs(inet->sport);
2225
2226 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2227 timer_active = 1;
2228 timer_expires = icsk->icsk_timeout;
2229 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2230 timer_active = 4;
2231 timer_expires = icsk->icsk_timeout;
2232 } else if (timer_pending(&sk->sk_timer)) {
2233 timer_active = 2;
2234 timer_expires = sk->sk_timer.expires;
2235 } else {
2236 timer_active = 0;
2237 timer_expires = jiffies;
2238 }
2239
2240 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2241 "%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
2242 i, src, srcp, dest, destp, sk->sk_state,
2243 tp->write_seq - tp->snd_una,
2244 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2245 (tp->rcv_nxt - tp->copied_seq),
2246 timer_active,
2247 jiffies_to_clock_t(timer_expires - jiffies),
2248 icsk->icsk_retransmits,
2249 sock_i_uid(sk),
2250 icsk->icsk_probes_out,
2251 sock_i_ino(sk),
2252 atomic_read(&sk->sk_refcnt), sk,
2253 jiffies_to_clock_t(icsk->icsk_rto),
2254 jiffies_to_clock_t(icsk->icsk_ack.ato),
2255 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2256 tp->snd_cwnd,
2257 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2258 len);
2259 }
2260
2261 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2262 struct seq_file *f, int i, int *len)
2263 {
2264 __be32 dest, src;
2265 __u16 destp, srcp;
2266 int ttd = tw->tw_ttd - jiffies;
2267
2268 if (ttd < 0)
2269 ttd = 0;
2270
2271 dest = tw->tw_daddr;
2272 src = tw->tw_rcv_saddr;
2273 destp = ntohs(tw->tw_dport);
2274 srcp = ntohs(tw->tw_sport);
2275
2276 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2277 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2278 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2279 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2280 atomic_read(&tw->tw_refcnt), tw, len);
2281 }
2282
2283 #define TMPSZ 150
2284
2285 static int tcp4_seq_show(struct seq_file *seq, void *v)
2286 {
2287 struct tcp_iter_state *st;
2288 int len;
2289
2290 if (v == SEQ_START_TOKEN) {
2291 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2292 " sl local_address rem_address st tx_queue "
2293 "rx_queue tr tm->when retrnsmt uid timeout "
2294 "inode");
2295 goto out;
2296 }
2297 st = seq->private;
2298
2299 switch (st->state) {
2300 case TCP_SEQ_STATE_LISTENING:
2301 case TCP_SEQ_STATE_ESTABLISHED:
2302 get_tcp4_sock(v, seq, st->num, &len);
2303 break;
2304 case TCP_SEQ_STATE_OPENREQ:
2305 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2306 break;
2307 case TCP_SEQ_STATE_TIME_WAIT:
2308 get_timewait4_sock(v, seq, st->num, &len);
2309 break;
2310 }
2311 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2312 out:
2313 return 0;
2314 }
2315
2316 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2317 .name = "tcp",
2318 .family = AF_INET,
2319 .seq_fops = {
2320 .owner = THIS_MODULE,
2321 },
2322 .seq_ops = {
2323 .show = tcp4_seq_show,
2324 },
2325 };
2326
2327 static int tcp4_proc_init_net(struct net *net)
2328 {
2329 return tcp_proc_register(net, &tcp4_seq_afinfo);
2330 }
2331
2332 static void tcp4_proc_exit_net(struct net *net)
2333 {
2334 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2335 }
2336
2337 static struct pernet_operations tcp4_net_ops = {
2338 .init = tcp4_proc_init_net,
2339 .exit = tcp4_proc_exit_net,
2340 };
2341
2342 int __init tcp4_proc_init(void)
2343 {
2344 return register_pernet_subsys(&tcp4_net_ops);
2345 }
2346
2347 void tcp4_proc_exit(void)
2348 {
2349 unregister_pernet_subsys(&tcp4_net_ops);
2350 }
2351 #endif /* CONFIG_PROC_FS */
2352
2353 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2354 {
2355 struct iphdr *iph = ip_hdr(skb);
2356
2357 switch (skb->ip_summed) {
2358 case CHECKSUM_COMPLETE:
2359 if (!tcp_v4_check(skb->len, iph->saddr, iph->daddr,
2360 skb->csum)) {
2361 skb->ip_summed = CHECKSUM_UNNECESSARY;
2362 break;
2363 }
2364
2365 /* fall through */
2366 case CHECKSUM_NONE:
2367 NAPI_GRO_CB(skb)->flush = 1;
2368 return NULL;
2369 }
2370
2371 return tcp_gro_receive(head, skb);
2372 }
2373 EXPORT_SYMBOL(tcp4_gro_receive);
2374
2375 int tcp4_gro_complete(struct sk_buff *skb)
2376 {
2377 struct iphdr *iph = ip_hdr(skb);
2378 struct tcphdr *th = tcp_hdr(skb);
2379
2380 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2381 iph->saddr, iph->daddr, 0);
2382 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2383
2384 return tcp_gro_complete(skb);
2385 }
2386 EXPORT_SYMBOL(tcp4_gro_complete);
2387
2388 struct proto tcp_prot = {
2389 .name = "TCP",
2390 .owner = THIS_MODULE,
2391 .close = tcp_close,
2392 .connect = tcp_v4_connect,
2393 .disconnect = tcp_disconnect,
2394 .accept = inet_csk_accept,
2395 .ioctl = tcp_ioctl,
2396 .init = tcp_v4_init_sock,
2397 .destroy = tcp_v4_destroy_sock,
2398 .shutdown = tcp_shutdown,
2399 .setsockopt = tcp_setsockopt,
2400 .getsockopt = tcp_getsockopt,
2401 .recvmsg = tcp_recvmsg,
2402 .backlog_rcv = tcp_v4_do_rcv,
2403 .hash = inet_hash,
2404 .unhash = inet_unhash,
2405 .get_port = inet_csk_get_port,
2406 .enter_memory_pressure = tcp_enter_memory_pressure,
2407 .sockets_allocated = &tcp_sockets_allocated,
2408 .orphan_count = &tcp_orphan_count,
2409 .memory_allocated = &tcp_memory_allocated,
2410 .memory_pressure = &tcp_memory_pressure,
2411 .sysctl_mem = sysctl_tcp_mem,
2412 .sysctl_wmem = sysctl_tcp_wmem,
2413 .sysctl_rmem = sysctl_tcp_rmem,
2414 .max_header = MAX_TCP_HEADER,
2415 .obj_size = sizeof(struct tcp_sock),
2416 .slab_flags = SLAB_DESTROY_BY_RCU,
2417 .twsk_prot = &tcp_timewait_sock_ops,
2418 .rsk_prot = &tcp_request_sock_ops,
2419 .h.hashinfo = &tcp_hashinfo,
2420 #ifdef CONFIG_COMPAT
2421 .compat_setsockopt = compat_tcp_setsockopt,
2422 .compat_getsockopt = compat_tcp_getsockopt,
2423 #endif
2424 };
2425
2426
2427 static int __net_init tcp_sk_init(struct net *net)
2428 {
2429 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2430 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2431 }
2432
2433 static void __net_exit tcp_sk_exit(struct net *net)
2434 {
2435 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2436 inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
2437 }
2438
2439 static struct pernet_operations __net_initdata tcp_sk_ops = {
2440 .init = tcp_sk_init,
2441 .exit = tcp_sk_exit,
2442 };
2443
2444 void __init tcp_v4_init(void)
2445 {
2446 inet_hashinfo_init(&tcp_hashinfo);
2447 if (register_pernet_subsys(&tcp_sk_ops))
2448 panic("Failed to create the TCP control socket.\n");
2449 }
2450
2451 EXPORT_SYMBOL(ipv4_specific);
2452 EXPORT_SYMBOL(tcp_hashinfo);
2453 EXPORT_SYMBOL(tcp_prot);
2454 EXPORT_SYMBOL(tcp_v4_conn_request);
2455 EXPORT_SYMBOL(tcp_v4_connect);
2456 EXPORT_SYMBOL(tcp_v4_do_rcv);
2457 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2458 EXPORT_SYMBOL(tcp_v4_send_check);
2459 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2460
2461 #ifdef CONFIG_PROC_FS
2462 EXPORT_SYMBOL(tcp_proc_register);
2463 EXPORT_SYMBOL(tcp_proc_unregister);
2464 #endif
2465 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2466
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree