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OMAP3430SDP: Enable config options CONFIG_OMAP_RESET_CLOCKS and CONFIG_SUSPEND
[linux-ginger.git] / net / ipv4 / tcp_ipv4.c
blobcd601a866c2f5856e3f8b69ffc3fd542c465e34a
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $
9 *
10 * IPv4 specific functions
11 *
12 *
13 * code split from:
14 * linux/ipv4/tcp.c
15 * linux/ipv4/tcp_input.c
16 * linux/ipv4/tcp_output.c
17 *
18 * See tcp.c for author information
19 *
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version
23 * 2 of the License, or (at your option) any later version.
24 */
25
26 /*
27 * Changes:
28 * David S. Miller : New socket lookup architecture.
29 * This code is dedicated to John Dyson.
30 * David S. Miller : Change semantics of established hash,
31 * half is devoted to TIME_WAIT sockets
32 * and the rest go in the other half.
33 * Andi Kleen : Add support for syncookies and fixed
34 * some bugs: ip options weren't passed to
35 * the TCP layer, missed a check for an
36 * ACK bit.
37 * Andi Kleen : Implemented fast path mtu discovery.
38 * Fixed many serious bugs in the
39 * request_sock handling and moved
40 * most of it into the af independent code.
41 * Added tail drop and some other bugfixes.
42 * Added new listen semantics.
43 * Mike McLagan : Routing by source
44 * Juan Jose Ciarlante: ip_dynaddr bits
45 * Andi Kleen: various fixes.
46 * Vitaly E. Lavrov : Transparent proxy revived after year
47 * coma.
48 * Andi Kleen : Fix new listen.
49 * Andi Kleen : Fix accept error reporting.
50 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
51 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
52 * a single port at the same time.
53 */
54
55
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64
65 #include <net/net_namespace.h>
66 #include <net/icmp.h>
67 #include <net/inet_hashtables.h>
68 #include <net/tcp.h>
69 #include <net/transp_v6.h>
70 #include <net/ipv6.h>
71 #include <net/inet_common.h>
72 #include <net/timewait_sock.h>
73 #include <net/xfrm.h>
74 #include <net/netdma.h>
75
76 #include <linux/inet.h>
77 #include <linux/ipv6.h>
78 #include <linux/stddef.h>
79 #include <linux/proc_fs.h>
80 #include <linux/seq_file.h>
81
82 #include <linux/crypto.h>
83 #include <linux/scatterlist.h>
84
85 int sysctl_tcp_tw_reuse __read_mostly;
86 int sysctl_tcp_low_latency __read_mostly;
87
88 /* Check TCP sequence numbers in ICMP packets. */
89 #define ICMP_MIN_LENGTH 8
90
91 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
92
93 #ifdef CONFIG_TCP_MD5SIG
94 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
95 __be32 addr);
96 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
97 __be32 saddr, __be32 daddr,
98 struct tcphdr *th, int protocol,
99 unsigned int tcplen);
100 #endif
101
102 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
103 .lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
104 .lhash_users = ATOMIC_INIT(0),
105 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
106 };
107
108 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
109 {
110 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
111 ip_hdr(skb)->saddr,
112 tcp_hdr(skb)->dest,
113 tcp_hdr(skb)->source);
114 }
115
116 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
117 {
118 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
119 struct tcp_sock *tp = tcp_sk(sk);
120
121 /* With PAWS, it is safe from the viewpoint
122 of data integrity. Even without PAWS it is safe provided sequence
123 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
124
125 Actually, the idea is close to VJ's one, only timestamp cache is
126 held not per host, but per port pair and TW bucket is used as state
127 holder.
128
129 If TW bucket has been already destroyed we fall back to VJ's scheme
130 and use initial timestamp retrieved from peer table.
131 */
132 if (tcptw->tw_ts_recent_stamp &&
133 (twp == NULL || (sysctl_tcp_tw_reuse &&
134 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
135 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
136 if (tp->write_seq == 0)
137 tp->write_seq = 1;
138 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
139 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
140 sock_hold(sktw);
141 return 1;
142 }
143
144 return 0;
145 }
146
147 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
148
149 /* This will initiate an outgoing connection. */
150 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
151 {
152 struct inet_sock *inet = inet_sk(sk);
153 struct tcp_sock *tp = tcp_sk(sk);
154 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
155 struct rtable *rt;
156 __be32 daddr, nexthop;
157 int tmp;
158 int err;
159
160 if (addr_len < sizeof(struct sockaddr_in))
161 return -EINVAL;
162
163 if (usin->sin_family != AF_INET)
164 return -EAFNOSUPPORT;
165
166 nexthop = daddr = usin->sin_addr.s_addr;
167 if (inet->opt && inet->opt->srr) {
168 if (!daddr)
169 return -EINVAL;
170 nexthop = inet->opt->faddr;
171 }
172
173 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
174 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
175 IPPROTO_TCP,
176 inet->sport, usin->sin_port, sk, 1);
177 if (tmp < 0) {
178 if (tmp == -ENETUNREACH)
179 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
180 return tmp;
181 }
182
183 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
184 ip_rt_put(rt);
185 return -ENETUNREACH;
186 }
187
188 if (!inet->opt || !inet->opt->srr)
189 daddr = rt->rt_dst;
190
191 if (!inet->saddr)
192 inet->saddr = rt->rt_src;
193 inet->rcv_saddr = inet->saddr;
194
195 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
196 /* Reset inherited state */
197 tp->rx_opt.ts_recent = 0;
198 tp->rx_opt.ts_recent_stamp = 0;
199 tp->write_seq = 0;
200 }
201
202 if (tcp_death_row.sysctl_tw_recycle &&
203 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
204 struct inet_peer *peer = rt_get_peer(rt);
205 /*
206 * VJ's idea. We save last timestamp seen from
207 * the destination in peer table, when entering state
208 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
209 * when trying new connection.
210 */
211 if (peer != NULL &&
212 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
213 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
214 tp->rx_opt.ts_recent = peer->tcp_ts;
215 }
216 }
217
218 inet->dport = usin->sin_port;
219 inet->daddr = daddr;
220
221 inet_csk(sk)->icsk_ext_hdr_len = 0;
222 if (inet->opt)
223 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
224
225 tp->rx_opt.mss_clamp = 536;
226
227 /* Socket identity is still unknown (sport may be zero).
228 * However we set state to SYN-SENT and not releasing socket
229 * lock select source port, enter ourselves into the hash tables and
230 * complete initialization after this.
231 */
232 tcp_set_state(sk, TCP_SYN_SENT);
233 err = inet_hash_connect(&tcp_death_row, sk);
234 if (err)
235 goto failure;
236
237 err = ip_route_newports(&rt, IPPROTO_TCP,
238 inet->sport, inet->dport, sk);
239 if (err)
240 goto failure;
241
242 /* OK, now commit destination to socket. */
243 sk->sk_gso_type = SKB_GSO_TCPV4;
244 sk_setup_caps(sk, &rt->u.dst);
245
246 if (!tp->write_seq)
247 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
248 inet->daddr,
249 inet->sport,
250 usin->sin_port);
251
252 inet->id = tp->write_seq ^ jiffies;
253
254 err = tcp_connect(sk);
255 rt = NULL;
256 if (err)
257 goto failure;
258
259 return 0;
260
261 failure:
262 /*
263 * This unhashes the socket and releases the local port,
264 * if necessary.
265 */
266 tcp_set_state(sk, TCP_CLOSE);
267 ip_rt_put(rt);
268 sk->sk_route_caps = 0;
269 inet->dport = 0;
270 return err;
271 }
272
273 /*
274 * This routine does path mtu discovery as defined in RFC1191.
275 */
276 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
277 {
278 struct dst_entry *dst;
279 struct inet_sock *inet = inet_sk(sk);
280
281 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
282 * send out by Linux are always <576bytes so they should go through
283 * unfragmented).
284 */
285 if (sk->sk_state == TCP_LISTEN)
286 return;
287
288 /* We don't check in the destentry if pmtu discovery is forbidden
289 * on this route. We just assume that no packet_to_big packets
290 * are send back when pmtu discovery is not active.
291 * There is a small race when the user changes this flag in the
292 * route, but I think that's acceptable.
293 */
294 if ((dst = __sk_dst_check(sk, 0)) == NULL)
295 return;
296
297 dst->ops->update_pmtu(dst, mtu);
298
299 /* Something is about to be wrong... Remember soft error
300 * for the case, if this connection will not able to recover.
301 */
302 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
303 sk->sk_err_soft = EMSGSIZE;
304
305 mtu = dst_mtu(dst);
306
307 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
308 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
309 tcp_sync_mss(sk, mtu);
310
311 /* Resend the TCP packet because it's
312 * clear that the old packet has been
313 * dropped. This is the new "fast" path mtu
314 * discovery.
315 */
316 tcp_simple_retransmit(sk);
317 } /* else let the usual retransmit timer handle it */
318 }
319
320 /*
321 * This routine is called by the ICMP module when it gets some
322 * sort of error condition. If err < 0 then the socket should
323 * be closed and the error returned to the user. If err > 0
324 * it's just the icmp type << 8 | icmp code. After adjustment
325 * header points to the first 8 bytes of the tcp header. We need
326 * to find the appropriate port.
327 *
328 * The locking strategy used here is very "optimistic". When
329 * someone else accesses the socket the ICMP is just dropped
330 * and for some paths there is no check at all.
331 * A more general error queue to queue errors for later handling
332 * is probably better.
333 *
334 */
335
336 void tcp_v4_err(struct sk_buff *skb, u32 info)
337 {
338 struct iphdr *iph = (struct iphdr *)skb->data;
339 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
340 struct tcp_sock *tp;
341 struct inet_sock *inet;
342 const int type = icmp_hdr(skb)->type;
343 const int code = icmp_hdr(skb)->code;
344 struct sock *sk;
345 __u32 seq;
346 int err;
347
348 if (skb->len < (iph->ihl << 2) + 8) {
349 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
350 return;
351 }
352
353 sk = inet_lookup(dev_net(skb->dev), &tcp_hashinfo, iph->daddr, th->dest,
354 iph->saddr, th->source, inet_iif(skb));
355 if (!sk) {
356 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
357 return;
358 }
359 if (sk->sk_state == TCP_TIME_WAIT) {
360 inet_twsk_put(inet_twsk(sk));
361 return;
362 }
363
364 bh_lock_sock(sk);
365 /* If too many ICMPs get dropped on busy
366 * servers this needs to be solved differently.
367 */
368 if (sock_owned_by_user(sk))
369 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
370
371 if (sk->sk_state == TCP_CLOSE)
372 goto out;
373
374 tp = tcp_sk(sk);
375 seq = ntohl(th->seq);
376 if (sk->sk_state != TCP_LISTEN &&
377 !between(seq, tp->snd_una, tp->snd_nxt)) {
378 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
379 goto out;
380 }
381
382 switch (type) {
383 case ICMP_SOURCE_QUENCH:
384 /* Just silently ignore these. */
385 goto out;
386 case ICMP_PARAMETERPROB:
387 err = EPROTO;
388 break;
389 case ICMP_DEST_UNREACH:
390 if (code > NR_ICMP_UNREACH)
391 goto out;
392
393 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
394 if (!sock_owned_by_user(sk))
395 do_pmtu_discovery(sk, iph, info);
396 goto out;
397 }
398
399 err = icmp_err_convert[code].errno;
400 break;
401 case ICMP_TIME_EXCEEDED:
402 err = EHOSTUNREACH;
403 break;
404 default:
405 goto out;
406 }
407
408 switch (sk->sk_state) {
409 struct request_sock *req, **prev;
410 case TCP_LISTEN:
411 if (sock_owned_by_user(sk))
412 goto out;
413
414 req = inet_csk_search_req(sk, &prev, th->dest,
415 iph->daddr, iph->saddr);
416 if (!req)
417 goto out;
418
419 /* ICMPs are not backlogged, hence we cannot get
420 an established socket here.
421 */
422 BUG_TRAP(!req->sk);
423
424 if (seq != tcp_rsk(req)->snt_isn) {
425 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
426 goto out;
427 }
428
429 /*
430 * Still in SYN_RECV, just remove it silently.
431 * There is no good way to pass the error to the newly
432 * created socket, and POSIX does not want network
433 * errors returned from accept().
434 */
435 inet_csk_reqsk_queue_drop(sk, req, prev);
436 goto out;
437
438 case TCP_SYN_SENT:
439 case TCP_SYN_RECV: /* Cannot happen.
440 It can f.e. if SYNs crossed.
441 */
442 if (!sock_owned_by_user(sk)) {
443 sk->sk_err = err;
444
445 sk->sk_error_report(sk);
446
447 tcp_done(sk);
448 } else {
449 sk->sk_err_soft = err;
450 }
451 goto out;
452 }
453
454 /* If we've already connected we will keep trying
455 * until we time out, or the user gives up.
456 *
457 * rfc1122 4.2.3.9 allows to consider as hard errors
458 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
459 * but it is obsoleted by pmtu discovery).
460 *
461 * Note, that in modern internet, where routing is unreliable
462 * and in each dark corner broken firewalls sit, sending random
463 * errors ordered by their masters even this two messages finally lose
464 * their original sense (even Linux sends invalid PORT_UNREACHs)
465 *
466 * Now we are in compliance with RFCs.
467 * --ANK (980905)
468 */
469
470 inet = inet_sk(sk);
471 if (!sock_owned_by_user(sk) && inet->recverr) {
472 sk->sk_err = err;
473 sk->sk_error_report(sk);
474 } else { /* Only an error on timeout */
475 sk->sk_err_soft = err;
476 }
477
478 out:
479 bh_unlock_sock(sk);
480 sock_put(sk);
481 }
482
483 /* This routine computes an IPv4 TCP checksum. */
484 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
485 {
486 struct inet_sock *inet = inet_sk(sk);
487 struct tcphdr *th = tcp_hdr(skb);
488
489 if (skb->ip_summed == CHECKSUM_PARTIAL) {
490 th->check = ~tcp_v4_check(len, inet->saddr,
491 inet->daddr, 0);
492 skb->csum_start = skb_transport_header(skb) - skb->head;
493 skb->csum_offset = offsetof(struct tcphdr, check);
494 } else {
495 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
496 csum_partial((char *)th,
497 th->doff << 2,
498 skb->csum));
499 }
500 }
501
502 int tcp_v4_gso_send_check(struct sk_buff *skb)
503 {
504 const struct iphdr *iph;
505 struct tcphdr *th;
506
507 if (!pskb_may_pull(skb, sizeof(*th)))
508 return -EINVAL;
509
510 iph = ip_hdr(skb);
511 th = tcp_hdr(skb);
512
513 th->check = 0;
514 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
515 skb->csum_start = skb_transport_header(skb) - skb->head;
516 skb->csum_offset = offsetof(struct tcphdr, check);
517 skb->ip_summed = CHECKSUM_PARTIAL;
518 return 0;
519 }
520
521 /*
522 * This routine will send an RST to the other tcp.
523 *
524 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
525 * for reset.
526 * Answer: if a packet caused RST, it is not for a socket
527 * existing in our system, if it is matched to a socket,
528 * it is just duplicate segment or bug in other side's TCP.
529 * So that we build reply only basing on parameters
530 * arrived with segment.
531 * Exception: precedence violation. We do not implement it in any case.
532 */
533
534 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
535 {
536 struct tcphdr *th = tcp_hdr(skb);
537 struct {
538 struct tcphdr th;
539 #ifdef CONFIG_TCP_MD5SIG
540 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
541 #endif
542 } rep;
543 struct ip_reply_arg arg;
544 #ifdef CONFIG_TCP_MD5SIG
545 struct tcp_md5sig_key *key;
546 #endif
547
548 /* Never send a reset in response to a reset. */
549 if (th->rst)
550 return;
551
552 if (skb->rtable->rt_type != RTN_LOCAL)
553 return;
554
555 /* Swap the send and the receive. */
556 memset(&rep, 0, sizeof(rep));
557 rep.th.dest = th->source;
558 rep.th.source = th->dest;
559 rep.th.doff = sizeof(struct tcphdr) / 4;
560 rep.th.rst = 1;
561
562 if (th->ack) {
563 rep.th.seq = th->ack_seq;
564 } else {
565 rep.th.ack = 1;
566 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
567 skb->len - (th->doff << 2));
568 }
569
570 memset(&arg, 0, sizeof(arg));
571 arg.iov[0].iov_base = (unsigned char *)&rep;
572 arg.iov[0].iov_len = sizeof(rep.th);
573
574 #ifdef CONFIG_TCP_MD5SIG
575 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
576 if (key) {
577 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
578 (TCPOPT_NOP << 16) |
579 (TCPOPT_MD5SIG << 8) |
580 TCPOLEN_MD5SIG);
581 /* Update length and the length the header thinks exists */
582 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
583 rep.th.doff = arg.iov[0].iov_len / 4;
584
585 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
586 key,
587 ip_hdr(skb)->daddr,
588 ip_hdr(skb)->saddr,
589 &rep.th, IPPROTO_TCP,
590 arg.iov[0].iov_len);
591 }
592 #endif
593 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
594 ip_hdr(skb)->saddr, /* XXX */
595 sizeof(struct tcphdr), IPPROTO_TCP, 0);
596 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
597
598 ip_send_reply(dev_net(skb->dst->dev)->ipv4.tcp_sock, skb,
599 &arg, arg.iov[0].iov_len);
600
601 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
602 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
603 }
604
605 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
606 outside socket context is ugly, certainly. What can I do?
607 */
608
609 static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
610 struct sk_buff *skb, u32 seq, u32 ack,
611 u32 win, u32 ts)
612 {
613 struct tcphdr *th = tcp_hdr(skb);
614 struct {
615 struct tcphdr th;
616 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
617 #ifdef CONFIG_TCP_MD5SIG
618 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
619 #endif
620 ];
621 } rep;
622 struct ip_reply_arg arg;
623 #ifdef CONFIG_TCP_MD5SIG
624 struct tcp_md5sig_key *key;
625 struct tcp_md5sig_key tw_key;
626 #endif
627
628 memset(&rep.th, 0, sizeof(struct tcphdr));
629 memset(&arg, 0, sizeof(arg));
630
631 arg.iov[0].iov_base = (unsigned char *)&rep;
632 arg.iov[0].iov_len = sizeof(rep.th);
633 if (ts) {
634 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
635 (TCPOPT_TIMESTAMP << 8) |
636 TCPOLEN_TIMESTAMP);
637 rep.opt[1] = htonl(tcp_time_stamp);
638 rep.opt[2] = htonl(ts);
639 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
640 }
641
642 /* Swap the send and the receive. */
643 rep.th.dest = th->source;
644 rep.th.source = th->dest;
645 rep.th.doff = arg.iov[0].iov_len / 4;
646 rep.th.seq = htonl(seq);
647 rep.th.ack_seq = htonl(ack);
648 rep.th.ack = 1;
649 rep.th.window = htons(win);
650
651 #ifdef CONFIG_TCP_MD5SIG
652 /*
653 * The SKB holds an imcoming packet, but may not have a valid ->sk
654 * pointer. This is especially the case when we're dealing with a
655 * TIME_WAIT ack, because the sk structure is long gone, and only
656 * the tcp_timewait_sock remains. So the md5 key is stashed in that
657 * structure, and we use it in preference. I believe that (twsk ||
658 * skb->sk) holds true, but we program defensively.
659 */
660 if (!twsk && skb->sk) {
661 key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
662 } else if (twsk && twsk->tw_md5_keylen) {
663 tw_key.key = twsk->tw_md5_key;
664 tw_key.keylen = twsk->tw_md5_keylen;
665 key = &tw_key;
666 } else
667 key = NULL;
668
669 if (key) {
670 int offset = (ts) ? 3 : 0;
671
672 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
673 (TCPOPT_NOP << 16) |
674 (TCPOPT_MD5SIG << 8) |
675 TCPOLEN_MD5SIG);
676 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
677 rep.th.doff = arg.iov[0].iov_len/4;
678
679 tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
680 key,
681 ip_hdr(skb)->daddr,
682 ip_hdr(skb)->saddr,
683 &rep.th, IPPROTO_TCP,
684 arg.iov[0].iov_len);
685 }
686 #endif
687 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
688 ip_hdr(skb)->saddr, /* XXX */
689 arg.iov[0].iov_len, IPPROTO_TCP, 0);
690 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
691 if (twsk)
692 arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
693
694 ip_send_reply(dev_net(skb->dev)->ipv4.tcp_sock, skb,
695 &arg, arg.iov[0].iov_len);
696
697 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
698 }
699
700 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
701 {
702 struct inet_timewait_sock *tw = inet_twsk(sk);
703 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
704
705 tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
706 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
707 tcptw->tw_ts_recent);
708
709 inet_twsk_put(tw);
710 }
711
712 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
713 struct request_sock *req)
714 {
715 tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
716 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
717 req->ts_recent);
718 }
719
720 /*
721 * Send a SYN-ACK after having received a SYN.
722 * This still operates on a request_sock only, not on a big
723 * socket.
724 */
725 static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
726 struct dst_entry *dst)
727 {
728 const struct inet_request_sock *ireq = inet_rsk(req);
729 int err = -1;
730 struct sk_buff * skb;
731
732 /* First, grab a route. */
733 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
734 return -1;
735
736 skb = tcp_make_synack(sk, dst, req);
737
738 if (skb) {
739 struct tcphdr *th = tcp_hdr(skb);
740
741 th->check = tcp_v4_check(skb->len,
742 ireq->loc_addr,
743 ireq->rmt_addr,
744 csum_partial((char *)th, skb->len,
745 skb->csum));
746
747 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
748 ireq->rmt_addr,
749 ireq->opt);
750 err = net_xmit_eval(err);
751 }
752
753 dst_release(dst);
754 return err;
755 }
756
757 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
758 {
759 return __tcp_v4_send_synack(sk, req, NULL);
760 }
761
762 /*
763 * IPv4 request_sock destructor.
764 */
765 static void tcp_v4_reqsk_destructor(struct request_sock *req)
766 {
767 kfree(inet_rsk(req)->opt);
768 }
769
770 #ifdef CONFIG_SYN_COOKIES
771 static void syn_flood_warning(struct sk_buff *skb)
772 {
773 static unsigned long warntime;
774
775 if (time_after(jiffies, (warntime + HZ * 60))) {
776 warntime = jiffies;
777 printk(KERN_INFO
778 "possible SYN flooding on port %d. Sending cookies.\n",
779 ntohs(tcp_hdr(skb)->dest));
780 }
781 }
782 #endif
783
784 /*
785 * Save and compile IPv4 options into the request_sock if needed.
786 */
787 static struct ip_options *tcp_v4_save_options(struct sock *sk,
788 struct sk_buff *skb)
789 {
790 struct ip_options *opt = &(IPCB(skb)->opt);
791 struct ip_options *dopt = NULL;
792
793 if (opt && opt->optlen) {
794 int opt_size = optlength(opt);
795 dopt = kmalloc(opt_size, GFP_ATOMIC);
796 if (dopt) {
797 if (ip_options_echo(dopt, skb)) {
798 kfree(dopt);
799 dopt = NULL;
800 }
801 }
802 }
803 return dopt;
804 }
805
806 #ifdef CONFIG_TCP_MD5SIG
807 /*
808 * RFC2385 MD5 checksumming requires a mapping of
809 * IP address->MD5 Key.
810 * We need to maintain these in the sk structure.
811 */
812
813 /* Find the Key structure for an address. */
814 static struct tcp_md5sig_key *
815 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
816 {
817 struct tcp_sock *tp = tcp_sk(sk);
818 int i;
819
820 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
821 return NULL;
822 for (i = 0; i < tp->md5sig_info->entries4; i++) {
823 if (tp->md5sig_info->keys4[i].addr == addr)
824 return &tp->md5sig_info->keys4[i].base;
825 }
826 return NULL;
827 }
828
829 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
830 struct sock *addr_sk)
831 {
832 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
833 }
834
835 EXPORT_SYMBOL(tcp_v4_md5_lookup);
836
837 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
838 struct request_sock *req)
839 {
840 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
841 }
842
843 /* This can be called on a newly created socket, from other files */
844 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
845 u8 *newkey, u8 newkeylen)
846 {
847 /* Add Key to the list */
848 struct tcp_md5sig_key *key;
849 struct tcp_sock *tp = tcp_sk(sk);
850 struct tcp4_md5sig_key *keys;
851
852 key = tcp_v4_md5_do_lookup(sk, addr);
853 if (key) {
854 /* Pre-existing entry - just update that one. */
855 kfree(key->key);
856 key->key = newkey;
857 key->keylen = newkeylen;
858 } else {
859 struct tcp_md5sig_info *md5sig;
860
861 if (!tp->md5sig_info) {
862 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
863 GFP_ATOMIC);
864 if (!tp->md5sig_info) {
865 kfree(newkey);
866 return -ENOMEM;
867 }
868 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
869 }
870 if (tcp_alloc_md5sig_pool() == NULL) {
871 kfree(newkey);
872 return -ENOMEM;
873 }
874 md5sig = tp->md5sig_info;
875
876 if (md5sig->alloced4 == md5sig->entries4) {
877 keys = kmalloc((sizeof(*keys) *
878 (md5sig->entries4 + 1)), GFP_ATOMIC);
879 if (!keys) {
880 kfree(newkey);
881 tcp_free_md5sig_pool();
882 return -ENOMEM;
883 }
884
885 if (md5sig->entries4)
886 memcpy(keys, md5sig->keys4,
887 sizeof(*keys) * md5sig->entries4);
888
889 /* Free old key list, and reference new one */
890 kfree(md5sig->keys4);
891 md5sig->keys4 = keys;
892 md5sig->alloced4++;
893 }
894 md5sig->entries4++;
895 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
896 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
897 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
898 }
899 return 0;
900 }
901
902 EXPORT_SYMBOL(tcp_v4_md5_do_add);
903
904 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
905 u8 *newkey, u8 newkeylen)
906 {
907 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
908 newkey, newkeylen);
909 }
910
911 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
912 {
913 struct tcp_sock *tp = tcp_sk(sk);
914 int i;
915
916 for (i = 0; i < tp->md5sig_info->entries4; i++) {
917 if (tp->md5sig_info->keys4[i].addr == addr) {
918 /* Free the key */
919 kfree(tp->md5sig_info->keys4[i].base.key);
920 tp->md5sig_info->entries4--;
921
922 if (tp->md5sig_info->entries4 == 0) {
923 kfree(tp->md5sig_info->keys4);
924 tp->md5sig_info->keys4 = NULL;
925 tp->md5sig_info->alloced4 = 0;
926 } else if (tp->md5sig_info->entries4 != i) {
927 /* Need to do some manipulation */
928 memmove(&tp->md5sig_info->keys4[i],
929 &tp->md5sig_info->keys4[i+1],
930 (tp->md5sig_info->entries4 - i) *
931 sizeof(struct tcp4_md5sig_key));
932 }
933 tcp_free_md5sig_pool();
934 return 0;
935 }
936 }
937 return -ENOENT;
938 }
939
940 EXPORT_SYMBOL(tcp_v4_md5_do_del);
941
942 static void tcp_v4_clear_md5_list(struct sock *sk)
943 {
944 struct tcp_sock *tp = tcp_sk(sk);
945
946 /* Free each key, then the set of key keys,
947 * the crypto element, and then decrement our
948 * hold on the last resort crypto.
949 */
950 if (tp->md5sig_info->entries4) {
951 int i;
952 for (i = 0; i < tp->md5sig_info->entries4; i++)
953 kfree(tp->md5sig_info->keys4[i].base.key);
954 tp->md5sig_info->entries4 = 0;
955 tcp_free_md5sig_pool();
956 }
957 if (tp->md5sig_info->keys4) {
958 kfree(tp->md5sig_info->keys4);
959 tp->md5sig_info->keys4 = NULL;
960 tp->md5sig_info->alloced4 = 0;
961 }
962 }
963
964 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
965 int optlen)
966 {
967 struct tcp_md5sig cmd;
968 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
969 u8 *newkey;
970
971 if (optlen < sizeof(cmd))
972 return -EINVAL;
973
974 if (copy_from_user(&cmd, optval, sizeof(cmd)))
975 return -EFAULT;
976
977 if (sin->sin_family != AF_INET)
978 return -EINVAL;
979
980 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
981 if (!tcp_sk(sk)->md5sig_info)
982 return -ENOENT;
983 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
984 }
985
986 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
987 return -EINVAL;
988
989 if (!tcp_sk(sk)->md5sig_info) {
990 struct tcp_sock *tp = tcp_sk(sk);
991 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
992
993 if (!p)
994 return -EINVAL;
995
996 tp->md5sig_info = p;
997 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
998 }
999
1000 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1001 if (!newkey)
1002 return -ENOMEM;
1003 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1004 newkey, cmd.tcpm_keylen);
1005 }
1006
1007 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1008 __be32 saddr, __be32 daddr,
1009 struct tcphdr *th, int protocol,
1010 unsigned int tcplen)
1011 {
1012 struct scatterlist sg[4];
1013 __u16 data_len;
1014 int block = 0;
1015 __sum16 old_checksum;
1016 struct tcp_md5sig_pool *hp;
1017 struct tcp4_pseudohdr *bp;
1018 struct hash_desc *desc;
1019 int err;
1020 unsigned int nbytes = 0;
1021
1022 /*
1023 * Okay, so RFC2385 is turned on for this connection,
1024 * so we need to generate the MD5 hash for the packet now.
1025 */
1026
1027 hp = tcp_get_md5sig_pool();
1028 if (!hp)
1029 goto clear_hash_noput;
1030
1031 bp = &hp->md5_blk.ip4;
1032 desc = &hp->md5_desc;
1033
1034 /*
1035 * 1. the TCP pseudo-header (in the order: source IP address,
1036 * destination IP address, zero-padded protocol number, and
1037 * segment length)
1038 */
1039 bp->saddr = saddr;
1040 bp->daddr = daddr;
1041 bp->pad = 0;
1042 bp->protocol = protocol;
1043 bp->len = htons(tcplen);
1044
1045 sg_init_table(sg, 4);
1046
1047 sg_set_buf(&sg[block++], bp, sizeof(*bp));
1048 nbytes += sizeof(*bp);
1049
1050 /* 2. the TCP header, excluding options, and assuming a
1051 * checksum of zero/
1052 */
1053 old_checksum = th->check;
1054 th->check = 0;
1055 sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
1056 nbytes += sizeof(struct tcphdr);
1057
1058 /* 3. the TCP segment data (if any) */
1059 data_len = tcplen - (th->doff << 2);
1060 if (data_len > 0) {
1061 unsigned char *data = (unsigned char *)th + (th->doff << 2);
1062 sg_set_buf(&sg[block++], data, data_len);
1063 nbytes += data_len;
1064 }
1065
1066 /* 4. an independently-specified key or password, known to both
1067 * TCPs and presumably connection-specific
1068 */
1069 sg_set_buf(&sg[block++], key->key, key->keylen);
1070 nbytes += key->keylen;
1071
1072 sg_mark_end(&sg[block - 1]);
1073
1074 /* Now store the Hash into the packet */
1075 err = crypto_hash_init(desc);
1076 if (err)
1077 goto clear_hash;
1078 err = crypto_hash_update(desc, sg, nbytes);
1079 if (err)
1080 goto clear_hash;
1081 err = crypto_hash_final(desc, md5_hash);
1082 if (err)
1083 goto clear_hash;
1084
1085 /* Reset header, and free up the crypto */
1086 tcp_put_md5sig_pool();
1087 th->check = old_checksum;
1088
1089 out:
1090 return 0;
1091 clear_hash:
1092 tcp_put_md5sig_pool();
1093 clear_hash_noput:
1094 memset(md5_hash, 0, 16);
1095 goto out;
1096 }
1097
1098 int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
1099 struct sock *sk,
1100 struct dst_entry *dst,
1101 struct request_sock *req,
1102 struct tcphdr *th, int protocol,
1103 unsigned int tcplen)
1104 {
1105 __be32 saddr, daddr;
1106
1107 if (sk) {
1108 saddr = inet_sk(sk)->saddr;
1109 daddr = inet_sk(sk)->daddr;
1110 } else {
1111 struct rtable *rt = (struct rtable *)dst;
1112 BUG_ON(!rt);
1113 saddr = rt->rt_src;
1114 daddr = rt->rt_dst;
1115 }
1116 return tcp_v4_do_calc_md5_hash(md5_hash, key,
1117 saddr, daddr,
1118 th, protocol, tcplen);
1119 }
1120
1121 EXPORT_SYMBOL(tcp_v4_calc_md5_hash);
1122
1123 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1124 {
1125 /*
1126 * This gets called for each TCP segment that arrives
1127 * so we want to be efficient.
1128 * We have 3 drop cases:
1129 * o No MD5 hash and one expected.
1130 * o MD5 hash and we're not expecting one.
1131 * o MD5 hash and its wrong.
1132 */
1133 __u8 *hash_location = NULL;
1134 struct tcp_md5sig_key *hash_expected;
1135 const struct iphdr *iph = ip_hdr(skb);
1136 struct tcphdr *th = tcp_hdr(skb);
1137 int length = (th->doff << 2) - sizeof(struct tcphdr);
1138 int genhash;
1139 unsigned char *ptr;
1140 unsigned char newhash[16];
1141
1142 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1143
1144 /*
1145 * If the TCP option length is less than the TCP_MD5SIG
1146 * option length, then we can shortcut
1147 */
1148 if (length < TCPOLEN_MD5SIG) {
1149 if (hash_expected)
1150 return 1;
1151 else
1152 return 0;
1153 }
1154
1155 /* Okay, we can't shortcut - we have to grub through the options */
1156 ptr = (unsigned char *)(th + 1);
1157 while (length > 0) {
1158 int opcode = *ptr++;
1159 int opsize;
1160
1161 switch (opcode) {
1162 case TCPOPT_EOL:
1163 goto done_opts;
1164 case TCPOPT_NOP:
1165 length--;
1166 continue;
1167 default:
1168 opsize = *ptr++;
1169 if (opsize < 2)
1170 goto done_opts;
1171 if (opsize > length)
1172 goto done_opts;
1173
1174 if (opcode == TCPOPT_MD5SIG) {
1175 hash_location = ptr;
1176 goto done_opts;
1177 }
1178 }
1179 ptr += opsize-2;
1180 length -= opsize;
1181 }
1182 done_opts:
1183 /* We've parsed the options - do we have a hash? */
1184 if (!hash_expected && !hash_location)
1185 return 0;
1186
1187 if (hash_expected && !hash_location) {
1188 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
1189 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1190 NIPQUAD(iph->saddr), ntohs(th->source),
1191 NIPQUAD(iph->daddr), ntohs(th->dest));
1192 return 1;
1193 }
1194
1195 if (!hash_expected && hash_location) {
1196 LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
1197 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
1198 NIPQUAD(iph->saddr), ntohs(th->source),
1199 NIPQUAD(iph->daddr), ntohs(th->dest));
1200 return 1;
1201 }
1202
1203 /* Okay, so this is hash_expected and hash_location -
1204 * so we need to calculate the checksum.
1205 */
1206 genhash = tcp_v4_do_calc_md5_hash(newhash,
1207 hash_expected,
1208 iph->saddr, iph->daddr,
1209 th, sk->sk_protocol,
1210 skb->len);
1211
1212 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1213 if (net_ratelimit()) {
1214 printk(KERN_INFO "MD5 Hash failed for "
1215 "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
1216 NIPQUAD(iph->saddr), ntohs(th->source),
1217 NIPQUAD(iph->daddr), ntohs(th->dest),
1218 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1219 }
1220 return 1;
1221 }
1222 return 0;
1223 }
1224
1225 #endif
1226
1227 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1228 .family = PF_INET,
1229 .obj_size = sizeof(struct tcp_request_sock),
1230 .rtx_syn_ack = tcp_v4_send_synack,
1231 .send_ack = tcp_v4_reqsk_send_ack,
1232 .destructor = tcp_v4_reqsk_destructor,
1233 .send_reset = tcp_v4_send_reset,
1234 };
1235
1236 #ifdef CONFIG_TCP_MD5SIG
1237 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1238 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1239 };
1240 #endif
1241
1242 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1243 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1244 .twsk_unique = tcp_twsk_unique,
1245 .twsk_destructor= tcp_twsk_destructor,
1246 };
1247
1248 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1249 {
1250 struct inet_request_sock *ireq;
1251 struct tcp_options_received tmp_opt;
1252 struct request_sock *req;
1253 __be32 saddr = ip_hdr(skb)->saddr;
1254 __be32 daddr = ip_hdr(skb)->daddr;
1255 __u32 isn = TCP_SKB_CB(skb)->when;
1256 struct dst_entry *dst = NULL;
1257 #ifdef CONFIG_SYN_COOKIES
1258 int want_cookie = 0;
1259 #else
1260 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1261 #endif
1262
1263 /* Never answer to SYNs send to broadcast or multicast */
1264 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1265 goto drop;
1266
1267 /* TW buckets are converted to open requests without
1268 * limitations, they conserve resources and peer is
1269 * evidently real one.
1270 */
1271 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1272 #ifdef CONFIG_SYN_COOKIES
1273 if (sysctl_tcp_syncookies) {
1274 want_cookie = 1;
1275 } else
1276 #endif
1277 goto drop;
1278 }
1279
1280 /* Accept backlog is full. If we have already queued enough
1281 * of warm entries in syn queue, drop request. It is better than
1282 * clogging syn queue with openreqs with exponentially increasing
1283 * timeout.
1284 */
1285 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1286 goto drop;
1287
1288 req = reqsk_alloc(&tcp_request_sock_ops);
1289 if (!req)
1290 goto drop;
1291
1292 #ifdef CONFIG_TCP_MD5SIG
1293 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1294 #endif
1295
1296 tcp_clear_options(&tmp_opt);
1297 tmp_opt.mss_clamp = 536;
1298 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1299
1300 tcp_parse_options(skb, &tmp_opt, 0);
1301
1302 if (want_cookie && !tmp_opt.saw_tstamp)
1303 tcp_clear_options(&tmp_opt);
1304
1305 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1306 /* Some OSes (unknown ones, but I see them on web server, which
1307 * contains information interesting only for windows'
1308 * users) do not send their stamp in SYN. It is easy case.
1309 * We simply do not advertise TS support.
1310 */
1311 tmp_opt.saw_tstamp = 0;
1312 tmp_opt.tstamp_ok = 0;
1313 }
1314 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1315
1316 tcp_openreq_init(req, &tmp_opt, skb);
1317
1318 if (security_inet_conn_request(sk, skb, req))
1319 goto drop_and_free;
1320
1321 ireq = inet_rsk(req);
1322 ireq->loc_addr = daddr;
1323 ireq->rmt_addr = saddr;
1324 ireq->opt = tcp_v4_save_options(sk, skb);
1325 if (!want_cookie)
1326 TCP_ECN_create_request(req, tcp_hdr(skb));
1327
1328 if (want_cookie) {
1329 #ifdef CONFIG_SYN_COOKIES
1330 syn_flood_warning(skb);
1331 req->cookie_ts = tmp_opt.tstamp_ok;
1332 #endif
1333 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1334 } else if (!isn) {
1335 struct inet_peer *peer = NULL;
1336
1337 /* VJ's idea. We save last timestamp seen
1338 * from the destination in peer table, when entering
1339 * state TIME-WAIT, and check against it before
1340 * accepting new connection request.
1341 *
1342 * If "isn" is not zero, this request hit alive
1343 * timewait bucket, so that all the necessary checks
1344 * are made in the function processing timewait state.
1345 */
1346 if (tmp_opt.saw_tstamp &&
1347 tcp_death_row.sysctl_tw_recycle &&
1348 (dst = inet_csk_route_req(sk, req)) != NULL &&
1349 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1350 peer->v4daddr == saddr) {
1351 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1352 (s32)(peer->tcp_ts - req->ts_recent) >
1353 TCP_PAWS_WINDOW) {
1354 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1355 goto drop_and_release;
1356 }
1357 }
1358 /* Kill the following clause, if you dislike this way. */
1359 else if (!sysctl_tcp_syncookies &&
1360 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1361 (sysctl_max_syn_backlog >> 2)) &&
1362 (!peer || !peer->tcp_ts_stamp) &&
1363 (!dst || !dst_metric(dst, RTAX_RTT))) {
1364 /* Without syncookies last quarter of
1365 * backlog is filled with destinations,
1366 * proven to be alive.
1367 * It means that we continue to communicate
1368 * to destinations, already remembered
1369 * to the moment of synflood.
1370 */
1371 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
1372 "request from " NIPQUAD_FMT "/%u\n",
1373 NIPQUAD(saddr),
1374 ntohs(tcp_hdr(skb)->source));
1375 goto drop_and_release;
1376 }
1377
1378 isn = tcp_v4_init_sequence(skb);
1379 }
1380 tcp_rsk(req)->snt_isn = isn;
1381
1382 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1383 goto drop_and_free;
1384
1385 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1386 return 0;
1387
1388 drop_and_release:
1389 dst_release(dst);
1390 drop_and_free:
1391 reqsk_free(req);
1392 drop:
1393 return 0;
1394 }
1395
1396
1397 /*
1398 * The three way handshake has completed - we got a valid synack -
1399 * now create the new socket.
1400 */
1401 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1402 struct request_sock *req,
1403 struct dst_entry *dst)
1404 {
1405 struct inet_request_sock *ireq;
1406 struct inet_sock *newinet;
1407 struct tcp_sock *newtp;
1408 struct sock *newsk;
1409 #ifdef CONFIG_TCP_MD5SIG
1410 struct tcp_md5sig_key *key;
1411 #endif
1412
1413 if (sk_acceptq_is_full(sk))
1414 goto exit_overflow;
1415
1416 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1417 goto exit;
1418
1419 newsk = tcp_create_openreq_child(sk, req, skb);
1420 if (!newsk)
1421 goto exit;
1422
1423 newsk->sk_gso_type = SKB_GSO_TCPV4;
1424 sk_setup_caps(newsk, dst);
1425
1426 newtp = tcp_sk(newsk);
1427 newinet = inet_sk(newsk);
1428 ireq = inet_rsk(req);
1429 newinet->daddr = ireq->rmt_addr;
1430 newinet->rcv_saddr = ireq->loc_addr;
1431 newinet->saddr = ireq->loc_addr;
1432 newinet->opt = ireq->opt;
1433 ireq->opt = NULL;
1434 newinet->mc_index = inet_iif(skb);
1435 newinet->mc_ttl = ip_hdr(skb)->ttl;
1436 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1437 if (newinet->opt)
1438 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1439 newinet->id = newtp->write_seq ^ jiffies;
1440
1441 tcp_mtup_init(newsk);
1442 tcp_sync_mss(newsk, dst_mtu(dst));
1443 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1444 tcp_initialize_rcv_mss(newsk);
1445
1446 #ifdef CONFIG_TCP_MD5SIG
1447 /* Copy over the MD5 key from the original socket */
1448 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1449 /*
1450 * We're using one, so create a matching key
1451 * on the newsk structure. If we fail to get
1452 * memory, then we end up not copying the key
1453 * across. Shucks.
1454 */
1455 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1456 if (newkey != NULL)
1457 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1458 newkey, key->keylen);
1459 }
1460 #endif
1461
1462 __inet_hash_nolisten(newsk);
1463 __inet_inherit_port(sk, newsk);
1464
1465 return newsk;
1466
1467 exit_overflow:
1468 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1469 exit:
1470 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1471 dst_release(dst);
1472 return NULL;
1473 }
1474
1475 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1476 {
1477 struct tcphdr *th = tcp_hdr(skb);
1478 const struct iphdr *iph = ip_hdr(skb);
1479 struct sock *nsk;
1480 struct request_sock **prev;
1481 /* Find possible connection requests. */
1482 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1483 iph->saddr, iph->daddr);
1484 if (req)
1485 return tcp_check_req(sk, skb, req, prev);
1486
1487 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1488 th->source, iph->daddr, th->dest, inet_iif(skb));
1489
1490 if (nsk) {
1491 if (nsk->sk_state != TCP_TIME_WAIT) {
1492 bh_lock_sock(nsk);
1493 return nsk;
1494 }
1495 inet_twsk_put(inet_twsk(nsk));
1496 return NULL;
1497 }
1498
1499 #ifdef CONFIG_SYN_COOKIES
1500 if (!th->rst && !th->syn && th->ack)
1501 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1502 #endif
1503 return sk;
1504 }
1505
1506 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1507 {
1508 const struct iphdr *iph = ip_hdr(skb);
1509
1510 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1511 if (!tcp_v4_check(skb->len, iph->saddr,
1512 iph->daddr, skb->csum)) {
1513 skb->ip_summed = CHECKSUM_UNNECESSARY;
1514 return 0;
1515 }
1516 }
1517
1518 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1519 skb->len, IPPROTO_TCP, 0);
1520
1521 if (skb->len <= 76) {
1522 return __skb_checksum_complete(skb);
1523 }
1524 return 0;
1525 }
1526
1527
1528 /* The socket must have it's spinlock held when we get
1529 * here.
1530 *
1531 * We have a potential double-lock case here, so even when
1532 * doing backlog processing we use the BH locking scheme.
1533 * This is because we cannot sleep with the original spinlock
1534 * held.
1535 */
1536 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1537 {
1538 struct sock *rsk;
1539 #ifdef CONFIG_TCP_MD5SIG
1540 /*
1541 * We really want to reject the packet as early as possible
1542 * if:
1543 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1544 * o There is an MD5 option and we're not expecting one
1545 */
1546 if (tcp_v4_inbound_md5_hash(sk, skb))
1547 goto discard;
1548 #endif
1549
1550 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1551 TCP_CHECK_TIMER(sk);
1552 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1553 rsk = sk;
1554 goto reset;
1555 }
1556 TCP_CHECK_TIMER(sk);
1557 return 0;
1558 }
1559
1560 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1561 goto csum_err;
1562
1563 if (sk->sk_state == TCP_LISTEN) {
1564 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1565 if (!nsk)
1566 goto discard;
1567
1568 if (nsk != sk) {
1569 if (tcp_child_process(sk, nsk, skb)) {
1570 rsk = nsk;
1571 goto reset;
1572 }
1573 return 0;
1574 }
1575 }
1576
1577 TCP_CHECK_TIMER(sk);
1578 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1579 rsk = sk;
1580 goto reset;
1581 }
1582 TCP_CHECK_TIMER(sk);
1583 return 0;
1584
1585 reset:
1586 tcp_v4_send_reset(rsk, skb);
1587 discard:
1588 kfree_skb(skb);
1589 /* Be careful here. If this function gets more complicated and
1590 * gcc suffers from register pressure on the x86, sk (in %ebx)
1591 * might be destroyed here. This current version compiles correctly,
1592 * but you have been warned.
1593 */
1594 return 0;
1595
1596 csum_err:
1597 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1598 goto discard;
1599 }
1600
1601 /*
1602 * From tcp_input.c
1603 */
1604
1605 int tcp_v4_rcv(struct sk_buff *skb)
1606 {
1607 const struct iphdr *iph;
1608 struct tcphdr *th;
1609 struct sock *sk;
1610 int ret;
1611
1612 if (skb->pkt_type != PACKET_HOST)
1613 goto discard_it;
1614
1615 /* Count it even if it's bad */
1616 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1617
1618 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1619 goto discard_it;
1620
1621 th = tcp_hdr(skb);
1622
1623 if (th->doff < sizeof(struct tcphdr) / 4)
1624 goto bad_packet;
1625 if (!pskb_may_pull(skb, th->doff * 4))
1626 goto discard_it;
1627
1628 /* An explanation is required here, I think.
1629 * Packet length and doff are validated by header prediction,
1630 * provided case of th->doff==0 is eliminated.
1631 * So, we defer the checks. */
1632 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1633 goto bad_packet;
1634
1635 th = tcp_hdr(skb);
1636 iph = ip_hdr(skb);
1637 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1638 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1639 skb->len - th->doff * 4);
1640 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1641 TCP_SKB_CB(skb)->when = 0;
1642 TCP_SKB_CB(skb)->flags = iph->tos;
1643 TCP_SKB_CB(skb)->sacked = 0;
1644
1645 sk = __inet_lookup(dev_net(skb->dev), &tcp_hashinfo, iph->saddr,
1646 th->source, iph->daddr, th->dest, inet_iif(skb));
1647 if (!sk)
1648 goto no_tcp_socket;
1649
1650 process:
1651 if (sk->sk_state == TCP_TIME_WAIT)
1652 goto do_time_wait;
1653
1654 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1655 goto discard_and_relse;
1656 nf_reset(skb);
1657
1658 if (sk_filter(sk, skb))
1659 goto discard_and_relse;
1660
1661 skb->dev = NULL;
1662
1663 bh_lock_sock_nested(sk);
1664 ret = 0;
1665 if (!sock_owned_by_user(sk)) {
1666 #ifdef CONFIG_NET_DMA
1667 struct tcp_sock *tp = tcp_sk(sk);
1668 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1669 tp->ucopy.dma_chan = get_softnet_dma();
1670 if (tp->ucopy.dma_chan)
1671 ret = tcp_v4_do_rcv(sk, skb);
1672 else
1673 #endif
1674 {
1675 if (!tcp_prequeue(sk, skb))
1676 ret = tcp_v4_do_rcv(sk, skb);
1677 }
1678 } else
1679 sk_add_backlog(sk, skb);
1680 bh_unlock_sock(sk);
1681
1682 sock_put(sk);
1683
1684 return ret;
1685
1686 no_tcp_socket:
1687 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1688 goto discard_it;
1689
1690 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1691 bad_packet:
1692 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1693 } else {
1694 tcp_v4_send_reset(NULL, skb);
1695 }
1696
1697 discard_it:
1698 /* Discard frame. */
1699 kfree_skb(skb);
1700 return 0;
1701
1702 discard_and_relse:
1703 sock_put(sk);
1704 goto discard_it;
1705
1706 do_time_wait:
1707 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1708 inet_twsk_put(inet_twsk(sk));
1709 goto discard_it;
1710 }
1711
1712 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1713 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1714 inet_twsk_put(inet_twsk(sk));
1715 goto discard_it;
1716 }
1717 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1718 case TCP_TW_SYN: {
1719 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1720 &tcp_hashinfo,
1721 iph->daddr, th->dest,
1722 inet_iif(skb));
1723 if (sk2) {
1724 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1725 inet_twsk_put(inet_twsk(sk));
1726 sk = sk2;
1727 goto process;
1728 }
1729 /* Fall through to ACK */
1730 }
1731 case TCP_TW_ACK:
1732 tcp_v4_timewait_ack(sk, skb);
1733 break;
1734 case TCP_TW_RST:
1735 goto no_tcp_socket;
1736 case TCP_TW_SUCCESS:;
1737 }
1738 goto discard_it;
1739 }
1740
1741 /* VJ's idea. Save last timestamp seen from this destination
1742 * and hold it at least for normal timewait interval to use for duplicate
1743 * segment detection in subsequent connections, before they enter synchronized
1744 * state.
1745 */
1746
1747 int tcp_v4_remember_stamp(struct sock *sk)
1748 {
1749 struct inet_sock *inet = inet_sk(sk);
1750 struct tcp_sock *tp = tcp_sk(sk);
1751 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1752 struct inet_peer *peer = NULL;
1753 int release_it = 0;
1754
1755 if (!rt || rt->rt_dst != inet->daddr) {
1756 peer = inet_getpeer(inet->daddr, 1);
1757 release_it = 1;
1758 } else {
1759 if (!rt->peer)
1760 rt_bind_peer(rt, 1);
1761 peer = rt->peer;
1762 }
1763
1764 if (peer) {
1765 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1766 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1767 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1768 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1769 peer->tcp_ts = tp->rx_opt.ts_recent;
1770 }
1771 if (release_it)
1772 inet_putpeer(peer);
1773 return 1;
1774 }
1775
1776 return 0;
1777 }
1778
1779 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1780 {
1781 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1782
1783 if (peer) {
1784 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1785
1786 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1787 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1788 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1789 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1790 peer->tcp_ts = tcptw->tw_ts_recent;
1791 }
1792 inet_putpeer(peer);
1793 return 1;
1794 }
1795
1796 return 0;
1797 }
1798
1799 struct inet_connection_sock_af_ops ipv4_specific = {
1800 .queue_xmit = ip_queue_xmit,
1801 .send_check = tcp_v4_send_check,
1802 .rebuild_header = inet_sk_rebuild_header,
1803 .conn_request = tcp_v4_conn_request,
1804 .syn_recv_sock = tcp_v4_syn_recv_sock,
1805 .remember_stamp = tcp_v4_remember_stamp,
1806 .net_header_len = sizeof(struct iphdr),
1807 .setsockopt = ip_setsockopt,
1808 .getsockopt = ip_getsockopt,
1809 .addr2sockaddr = inet_csk_addr2sockaddr,
1810 .sockaddr_len = sizeof(struct sockaddr_in),
1811 .bind_conflict = inet_csk_bind_conflict,
1812 #ifdef CONFIG_COMPAT
1813 .compat_setsockopt = compat_ip_setsockopt,
1814 .compat_getsockopt = compat_ip_getsockopt,
1815 #endif
1816 };
1817
1818 #ifdef CONFIG_TCP_MD5SIG
1819 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1820 .md5_lookup = tcp_v4_md5_lookup,
1821 .calc_md5_hash = tcp_v4_calc_md5_hash,
1822 .md5_add = tcp_v4_md5_add_func,
1823 .md5_parse = tcp_v4_parse_md5_keys,
1824 };
1825 #endif
1826
1827 /* NOTE: A lot of things set to zero explicitly by call to
1828 * sk_alloc() so need not be done here.
1829 */
1830 static int tcp_v4_init_sock(struct sock *sk)
1831 {
1832 struct inet_connection_sock *icsk = inet_csk(sk);
1833 struct tcp_sock *tp = tcp_sk(sk);
1834
1835 skb_queue_head_init(&tp->out_of_order_queue);
1836 tcp_init_xmit_timers(sk);
1837 tcp_prequeue_init(tp);
1838
1839 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1840 tp->mdev = TCP_TIMEOUT_INIT;
1841
1842 /* So many TCP implementations out there (incorrectly) count the
1843 * initial SYN frame in their delayed-ACK and congestion control
1844 * algorithms that we must have the following bandaid to talk
1845 * efficiently to them. -DaveM
1846 */
1847 tp->snd_cwnd = 2;
1848
1849 /* See draft-stevens-tcpca-spec-01 for discussion of the
1850 * initialization of these values.
1851 */
1852 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1853 tp->snd_cwnd_clamp = ~0;
1854 tp->mss_cache = 536;
1855
1856 tp->reordering = sysctl_tcp_reordering;
1857 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1858
1859 sk->sk_state = TCP_CLOSE;
1860
1861 sk->sk_write_space = sk_stream_write_space;
1862 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1863
1864 icsk->icsk_af_ops = &ipv4_specific;
1865 icsk->icsk_sync_mss = tcp_sync_mss;
1866 #ifdef CONFIG_TCP_MD5SIG
1867 tp->af_specific = &tcp_sock_ipv4_specific;
1868 #endif
1869
1870 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1871 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1872
1873 atomic_inc(&tcp_sockets_allocated);
1874
1875 return 0;
1876 }
1877
1878 int tcp_v4_destroy_sock(struct sock *sk)
1879 {
1880 struct tcp_sock *tp = tcp_sk(sk);
1881
1882 tcp_clear_xmit_timers(sk);
1883
1884 tcp_cleanup_congestion_control(sk);
1885
1886 /* Cleanup up the write buffer. */
1887 tcp_write_queue_purge(sk);
1888
1889 /* Cleans up our, hopefully empty, out_of_order_queue. */
1890 __skb_queue_purge(&tp->out_of_order_queue);
1891
1892 #ifdef CONFIG_TCP_MD5SIG
1893 /* Clean up the MD5 key list, if any */
1894 if (tp->md5sig_info) {
1895 tcp_v4_clear_md5_list(sk);
1896 kfree(tp->md5sig_info);
1897 tp->md5sig_info = NULL;
1898 }
1899 #endif
1900
1901 #ifdef CONFIG_NET_DMA
1902 /* Cleans up our sk_async_wait_queue */
1903 __skb_queue_purge(&sk->sk_async_wait_queue);
1904 #endif
1905
1906 /* Clean prequeue, it must be empty really */
1907 __skb_queue_purge(&tp->ucopy.prequeue);
1908
1909 /* Clean up a referenced TCP bind bucket. */
1910 if (inet_csk(sk)->icsk_bind_hash)
1911 inet_put_port(sk);
1912
1913 /*
1914 * If sendmsg cached page exists, toss it.
1915 */
1916 if (sk->sk_sndmsg_page) {
1917 __free_page(sk->sk_sndmsg_page);
1918 sk->sk_sndmsg_page = NULL;
1919 }
1920
1921 if (tp->defer_tcp_accept.request) {
1922 reqsk_free(tp->defer_tcp_accept.request);
1923 sock_put(tp->defer_tcp_accept.listen_sk);
1924 sock_put(sk);
1925 tp->defer_tcp_accept.listen_sk = NULL;
1926 tp->defer_tcp_accept.request = NULL;
1927 }
1928
1929 atomic_dec(&tcp_sockets_allocated);
1930
1931 return 0;
1932 }
1933
1934 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1935
1936 #ifdef CONFIG_PROC_FS
1937 /* Proc filesystem TCP sock list dumping. */
1938
1939 static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1940 {
1941 return hlist_empty(head) ? NULL :
1942 list_entry(head->first, struct inet_timewait_sock, tw_node);
1943 }
1944
1945 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1946 {
1947 return tw->tw_node.next ?
1948 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1949 }
1950
1951 static void *listening_get_next(struct seq_file *seq, void *cur)
1952 {
1953 struct inet_connection_sock *icsk;
1954 struct hlist_node *node;
1955 struct sock *sk = cur;
1956 struct tcp_iter_state* st = seq->private;
1957 struct net *net = seq_file_net(seq);
1958
1959 if (!sk) {
1960 st->bucket = 0;
1961 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1962 goto get_sk;
1963 }
1964
1965 ++st->num;
1966
1967 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1968 struct request_sock *req = cur;
1969
1970 icsk = inet_csk(st->syn_wait_sk);
1971 req = req->dl_next;
1972 while (1) {
1973 while (req) {
1974 if (req->rsk_ops->family == st->family &&
1975 net_eq(sock_net(req->sk), net)) {
1976 cur = req;
1977 goto out;
1978 }
1979 req = req->dl_next;
1980 }
1981 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1982 break;
1983 get_req:
1984 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1985 }
1986 sk = sk_next(st->syn_wait_sk);
1987 st->state = TCP_SEQ_STATE_LISTENING;
1988 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1989 } else {
1990 icsk = inet_csk(sk);
1991 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1992 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1993 goto start_req;
1994 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1995 sk = sk_next(sk);
1996 }
1997 get_sk:
1998 sk_for_each_from(sk, node) {
1999 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
2000 cur = sk;
2001 goto out;
2002 }
2003 icsk = inet_csk(sk);
2004 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2005 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2006 start_req:
2007 st->uid = sock_i_uid(sk);
2008 st->syn_wait_sk = sk;
2009 st->state = TCP_SEQ_STATE_OPENREQ;
2010 st->sbucket = 0;
2011 goto get_req;
2012 }
2013 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2014 }
2015 if (++st->bucket < INET_LHTABLE_SIZE) {
2016 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
2017 goto get_sk;
2018 }
2019 cur = NULL;
2020 out:
2021 return cur;
2022 }
2023
2024 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2025 {
2026 void *rc = listening_get_next(seq, NULL);
2027
2028 while (rc && *pos) {
2029 rc = listening_get_next(seq, rc);
2030 --*pos;
2031 }
2032 return rc;
2033 }
2034
2035 static void *established_get_first(struct seq_file *seq)
2036 {
2037 struct tcp_iter_state* st = seq->private;
2038 struct net *net = seq_file_net(seq);
2039 void *rc = NULL;
2040
2041 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2042 struct sock *sk;
2043 struct hlist_node *node;
2044 struct inet_timewait_sock *tw;
2045 rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2046
2047 read_lock_bh(lock);
2048 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2049 if (sk->sk_family != st->family ||
2050 !net_eq(sock_net(sk), net)) {
2051 continue;
2052 }
2053 rc = sk;
2054 goto out;
2055 }
2056 st->state = TCP_SEQ_STATE_TIME_WAIT;
2057 inet_twsk_for_each(tw, node,
2058 &tcp_hashinfo.ehash[st->bucket].twchain) {
2059 if (tw->tw_family != st->family ||
2060 !net_eq(twsk_net(tw), net)) {
2061 continue;
2062 }
2063 rc = tw;
2064 goto out;
2065 }
2066 read_unlock_bh(lock);
2067 st->state = TCP_SEQ_STATE_ESTABLISHED;
2068 }
2069 out:
2070 return rc;
2071 }
2072
2073 static void *established_get_next(struct seq_file *seq, void *cur)
2074 {
2075 struct sock *sk = cur;
2076 struct inet_timewait_sock *tw;
2077 struct hlist_node *node;
2078 struct tcp_iter_state* st = seq->private;
2079 struct net *net = seq_file_net(seq);
2080
2081 ++st->num;
2082
2083 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2084 tw = cur;
2085 tw = tw_next(tw);
2086 get_tw:
2087 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2088 tw = tw_next(tw);
2089 }
2090 if (tw) {
2091 cur = tw;
2092 goto out;
2093 }
2094 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2095 st->state = TCP_SEQ_STATE_ESTABLISHED;
2096
2097 if (++st->bucket < tcp_hashinfo.ehash_size) {
2098 read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2099 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
2100 } else {
2101 cur = NULL;
2102 goto out;
2103 }
2104 } else
2105 sk = sk_next(sk);
2106
2107 sk_for_each_from(sk, node) {
2108 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2109 goto found;
2110 }
2111
2112 st->state = TCP_SEQ_STATE_TIME_WAIT;
2113 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2114 goto get_tw;
2115 found:
2116 cur = sk;
2117 out:
2118 return cur;
2119 }
2120
2121 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2122 {
2123 void *rc = established_get_first(seq);
2124
2125 while (rc && pos) {
2126 rc = established_get_next(seq, rc);
2127 --pos;
2128 }
2129 return rc;
2130 }
2131
2132 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2133 {
2134 void *rc;
2135 struct tcp_iter_state* st = seq->private;
2136
2137 inet_listen_lock(&tcp_hashinfo);
2138 st->state = TCP_SEQ_STATE_LISTENING;
2139 rc = listening_get_idx(seq, &pos);
2140
2141 if (!rc) {
2142 inet_listen_unlock(&tcp_hashinfo);
2143 st->state = TCP_SEQ_STATE_ESTABLISHED;
2144 rc = established_get_idx(seq, pos);
2145 }
2146
2147 return rc;
2148 }
2149
2150 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2151 {
2152 struct tcp_iter_state* st = seq->private;
2153 st->state = TCP_SEQ_STATE_LISTENING;
2154 st->num = 0;
2155 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2156 }
2157
2158 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2159 {
2160 void *rc = NULL;
2161 struct tcp_iter_state* st;
2162
2163 if (v == SEQ_START_TOKEN) {
2164 rc = tcp_get_idx(seq, 0);
2165 goto out;
2166 }
2167 st = seq->private;
2168
2169 switch (st->state) {
2170 case TCP_SEQ_STATE_OPENREQ:
2171 case TCP_SEQ_STATE_LISTENING:
2172 rc = listening_get_next(seq, v);
2173 if (!rc) {
2174 inet_listen_unlock(&tcp_hashinfo);
2175 st->state = TCP_SEQ_STATE_ESTABLISHED;
2176 rc = established_get_first(seq);
2177 }
2178 break;
2179 case TCP_SEQ_STATE_ESTABLISHED:
2180 case TCP_SEQ_STATE_TIME_WAIT:
2181 rc = established_get_next(seq, v);
2182 break;
2183 }
2184 out:
2185 ++*pos;
2186 return rc;
2187 }
2188
2189 static void tcp_seq_stop(struct seq_file *seq, void *v)
2190 {
2191 struct tcp_iter_state* st = seq->private;
2192
2193 switch (st->state) {
2194 case TCP_SEQ_STATE_OPENREQ:
2195 if (v) {
2196 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2197 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2198 }
2199 case TCP_SEQ_STATE_LISTENING:
2200 if (v != SEQ_START_TOKEN)
2201 inet_listen_unlock(&tcp_hashinfo);
2202 break;
2203 case TCP_SEQ_STATE_TIME_WAIT:
2204 case TCP_SEQ_STATE_ESTABLISHED:
2205 if (v)
2206 read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2207 break;
2208 }
2209 }
2210
2211 static int tcp_seq_open(struct inode *inode, struct file *file)
2212 {
2213 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2214 struct tcp_iter_state *s;
2215 int err;
2216
2217 err = seq_open_net(inode, file, &afinfo->seq_ops,
2218 sizeof(struct tcp_iter_state));
2219 if (err < 0)
2220 return err;
2221
2222 s = ((struct seq_file *)file->private_data)->private;
2223 s->family = afinfo->family;
2224 return 0;
2225 }
2226
2227 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2228 {
2229 int rc = 0;
2230 struct proc_dir_entry *p;
2231
2232 afinfo->seq_fops.open = tcp_seq_open;
2233 afinfo->seq_fops.read = seq_read;
2234 afinfo->seq_fops.llseek = seq_lseek;
2235 afinfo->seq_fops.release = seq_release_net;
2236
2237 afinfo->seq_ops.start = tcp_seq_start;
2238 afinfo->seq_ops.next = tcp_seq_next;
2239 afinfo->seq_ops.stop = tcp_seq_stop;
2240
2241 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2242 &afinfo->seq_fops, afinfo);
2243 if (!p)
2244 rc = -ENOMEM;
2245 return rc;
2246 }
2247
2248 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2249 {
2250 proc_net_remove(net, afinfo->name);
2251 }
2252
2253 static void get_openreq4(struct sock *sk, struct request_sock *req,
2254 struct seq_file *f, int i, int uid, int *len)
2255 {
2256 const struct inet_request_sock *ireq = inet_rsk(req);
2257 int ttd = req->expires - jiffies;
2258
2259 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2260 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2261 i,
2262 ireq->loc_addr,
2263 ntohs(inet_sk(sk)->sport),
2264 ireq->rmt_addr,
2265 ntohs(ireq->rmt_port),
2266 TCP_SYN_RECV,
2267 0, 0, /* could print option size, but that is af dependent. */
2268 1, /* timers active (only the expire timer) */
2269 jiffies_to_clock_t(ttd),
2270 req->retrans,
2271 uid,
2272 0, /* non standard timer */
2273 0, /* open_requests have no inode */
2274 atomic_read(&sk->sk_refcnt),
2275 req,
2276 len);
2277 }
2278
2279 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2280 {
2281 int timer_active;
2282 unsigned long timer_expires;
2283 struct tcp_sock *tp = tcp_sk(sk);
2284 const struct inet_connection_sock *icsk = inet_csk(sk);
2285 struct inet_sock *inet = inet_sk(sk);
2286 __be32 dest = inet->daddr;
2287 __be32 src = inet->rcv_saddr;
2288 __u16 destp = ntohs(inet->dport);
2289 __u16 srcp = ntohs(inet->sport);
2290
2291 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2292 timer_active = 1;
2293 timer_expires = icsk->icsk_timeout;
2294 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2295 timer_active = 4;
2296 timer_expires = icsk->icsk_timeout;
2297 } else if (timer_pending(&sk->sk_timer)) {
2298 timer_active = 2;
2299 timer_expires = sk->sk_timer.expires;
2300 } else {
2301 timer_active = 0;
2302 timer_expires = jiffies;
2303 }
2304
2305 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2306 "%08X %5d %8d %lu %d %p %u %u %u %u %d%n",
2307 i, src, srcp, dest, destp, sk->sk_state,
2308 tp->write_seq - tp->snd_una,
2309 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2310 (tp->rcv_nxt - tp->copied_seq),
2311 timer_active,
2312 jiffies_to_clock_t(timer_expires - jiffies),
2313 icsk->icsk_retransmits,
2314 sock_i_uid(sk),
2315 icsk->icsk_probes_out,
2316 sock_i_ino(sk),
2317 atomic_read(&sk->sk_refcnt), sk,
2318 icsk->icsk_rto,
2319 icsk->icsk_ack.ato,
2320 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2321 tp->snd_cwnd,
2322 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2323 len);
2324 }
2325
2326 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2327 struct seq_file *f, int i, int *len)
2328 {
2329 __be32 dest, src;
2330 __u16 destp, srcp;
2331 int ttd = tw->tw_ttd - jiffies;
2332
2333 if (ttd < 0)
2334 ttd = 0;
2335
2336 dest = tw->tw_daddr;
2337 src = tw->tw_rcv_saddr;
2338 destp = ntohs(tw->tw_dport);
2339 srcp = ntohs(tw->tw_sport);
2340
2341 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2342 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2343 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2344 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2345 atomic_read(&tw->tw_refcnt), tw, len);
2346 }
2347
2348 #define TMPSZ 150
2349
2350 static int tcp4_seq_show(struct seq_file *seq, void *v)
2351 {
2352 struct tcp_iter_state* st;
2353 int len;
2354
2355 if (v == SEQ_START_TOKEN) {
2356 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2357 " sl local_address rem_address st tx_queue "
2358 "rx_queue tr tm->when retrnsmt uid timeout "
2359 "inode");
2360 goto out;
2361 }
2362 st = seq->private;
2363
2364 switch (st->state) {
2365 case TCP_SEQ_STATE_LISTENING:
2366 case TCP_SEQ_STATE_ESTABLISHED:
2367 get_tcp4_sock(v, seq, st->num, &len);
2368 break;
2369 case TCP_SEQ_STATE_OPENREQ:
2370 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2371 break;
2372 case TCP_SEQ_STATE_TIME_WAIT:
2373 get_timewait4_sock(v, seq, st->num, &len);
2374 break;
2375 }
2376 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2377 out:
2378 return 0;
2379 }
2380
2381 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2382 .name = "tcp",
2383 .family = AF_INET,
2384 .seq_fops = {
2385 .owner = THIS_MODULE,
2386 },
2387 .seq_ops = {
2388 .show = tcp4_seq_show,
2389 },
2390 };
2391
2392 static int tcp4_proc_init_net(struct net *net)
2393 {
2394 return tcp_proc_register(net, &tcp4_seq_afinfo);
2395 }
2396
2397 static void tcp4_proc_exit_net(struct net *net)
2398 {
2399 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2400 }
2401
2402 static struct pernet_operations tcp4_net_ops = {
2403 .init = tcp4_proc_init_net,
2404 .exit = tcp4_proc_exit_net,
2405 };
2406
2407 int __init tcp4_proc_init(void)
2408 {
2409 return register_pernet_subsys(&tcp4_net_ops);
2410 }
2411
2412 void tcp4_proc_exit(void)
2413 {
2414 unregister_pernet_subsys(&tcp4_net_ops);
2415 }
2416 #endif /* CONFIG_PROC_FS */
2417
2418 struct proto tcp_prot = {
2419 .name = "TCP",
2420 .owner = THIS_MODULE,
2421 .close = tcp_close,
2422 .connect = tcp_v4_connect,
2423 .disconnect = tcp_disconnect,
2424 .accept = inet_csk_accept,
2425 .ioctl = tcp_ioctl,
2426 .init = tcp_v4_init_sock,
2427 .destroy = tcp_v4_destroy_sock,
2428 .shutdown = tcp_shutdown,
2429 .setsockopt = tcp_setsockopt,
2430 .getsockopt = tcp_getsockopt,
2431 .recvmsg = tcp_recvmsg,
2432 .backlog_rcv = tcp_v4_do_rcv,
2433 .hash = inet_hash,
2434 .unhash = inet_unhash,
2435 .get_port = inet_csk_get_port,
2436 .enter_memory_pressure = tcp_enter_memory_pressure,
2437 .sockets_allocated = &tcp_sockets_allocated,
2438 .orphan_count = &tcp_orphan_count,
2439 .memory_allocated = &tcp_memory_allocated,
2440 .memory_pressure = &tcp_memory_pressure,
2441 .sysctl_mem = sysctl_tcp_mem,
2442 .sysctl_wmem = sysctl_tcp_wmem,
2443 .sysctl_rmem = sysctl_tcp_rmem,
2444 .max_header = MAX_TCP_HEADER,
2445 .obj_size = sizeof(struct tcp_sock),
2446 .twsk_prot = &tcp_timewait_sock_ops,
2447 .rsk_prot = &tcp_request_sock_ops,
2448 .h.hashinfo = &tcp_hashinfo,
2449 #ifdef CONFIG_COMPAT
2450 .compat_setsockopt = compat_tcp_setsockopt,
2451 .compat_getsockopt = compat_tcp_getsockopt,
2452 #endif
2453 };
2454
2455
2456 static int __net_init tcp_sk_init(struct net *net)
2457 {
2458 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2459 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2460 }
2461
2462 static void __net_exit tcp_sk_exit(struct net *net)
2463 {
2464 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2465 }
2466
2467 static struct pernet_operations __net_initdata tcp_sk_ops = {
2468 .init = tcp_sk_init,
2469 .exit = tcp_sk_exit,
2470 };
2471
2472 void __init tcp_v4_init(void)
2473 {
2474 if (register_pernet_device(&tcp_sk_ops))
2475 panic("Failed to create the TCP control socket.\n");
2476 }
2477
2478 EXPORT_SYMBOL(ipv4_specific);
2479 EXPORT_SYMBOL(tcp_hashinfo);
2480 EXPORT_SYMBOL(tcp_prot);
2481 EXPORT_SYMBOL(tcp_v4_conn_request);
2482 EXPORT_SYMBOL(tcp_v4_connect);
2483 EXPORT_SYMBOL(tcp_v4_do_rcv);
2484 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2485 EXPORT_SYMBOL(tcp_v4_send_check);
2486 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2487
2488 #ifdef CONFIG_PROC_FS
2489 EXPORT_SYMBOL(tcp_proc_register);
2490 EXPORT_SYMBOL(tcp_proc_unregister);
2491 #endif
2492 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2493
Linux for Ginger Game Console