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tcp: Change possible SYN flooding messages
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv4 / tcp_ipv4.c
blobc34f015139453245238e7bd5086c35d5b5a760f4
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 #include <linux/slab.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 #include <net/secure_seq.h>
76
77 #include <linux/inet.h>
78 #include <linux/ipv6.h>
79 #include <linux/stddef.h>
80 #include <linux/proc_fs.h>
81 #include <linux/seq_file.h>
82
83 #include <linux/crypto.h>
84 #include <linux/scatterlist.h>
85
86 int sysctl_tcp_tw_reuse __read_mostly;
87 int sysctl_tcp_low_latency __read_mostly;
88 EXPORT_SYMBOL(sysctl_tcp_low_latency);
89
90
91 #ifdef CONFIG_TCP_MD5SIG
92 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
93 __be32 addr);
94 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, struct tcphdr *th);
96 #else
97 static inline
98 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
99 {
100 return NULL;
101 }
102 #endif
103
104 struct inet_hashinfo tcp_hashinfo;
105 EXPORT_SYMBOL(tcp_hashinfo);
106
107 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
108 {
109 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
110 ip_hdr(skb)->saddr,
111 tcp_hdr(skb)->dest,
112 tcp_hdr(skb)->source);
113 }
114
115 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
116 {
117 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
118 struct tcp_sock *tp = tcp_sk(sk);
119
120 /* With PAWS, it is safe from the viewpoint
121 of data integrity. Even without PAWS it is safe provided sequence
122 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
123
124 Actually, the idea is close to VJ's one, only timestamp cache is
125 held not per host, but per port pair and TW bucket is used as state
126 holder.
127
128 If TW bucket has been already destroyed we fall back to VJ's scheme
129 and use initial timestamp retrieved from peer table.
130 */
131 if (tcptw->tw_ts_recent_stamp &&
132 (twp == NULL || (sysctl_tcp_tw_reuse &&
133 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
134 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
135 if (tp->write_seq == 0)
136 tp->write_seq = 1;
137 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
138 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
139 sock_hold(sktw);
140 return 1;
141 }
142
143 return 0;
144 }
145 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
146
147 /* This will initiate an outgoing connection. */
148 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
149 {
150 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
151 struct inet_sock *inet = inet_sk(sk);
152 struct tcp_sock *tp = tcp_sk(sk);
153 __be16 orig_sport, orig_dport;
154 __be32 daddr, nexthop;
155 struct flowi4 *fl4;
156 struct rtable *rt;
157 int err;
158 struct ip_options_rcu *inet_opt;
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 inet_opt = rcu_dereference_protected(inet->inet_opt,
168 sock_owned_by_user(sk));
169 if (inet_opt && inet_opt->opt.srr) {
170 if (!daddr)
171 return -EINVAL;
172 nexthop = inet_opt->opt.faddr;
173 }
174
175 orig_sport = inet->inet_sport;
176 orig_dport = usin->sin_port;
177 fl4 = &inet->cork.fl.u.ip4;
178 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
179 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
180 IPPROTO_TCP,
181 orig_sport, orig_dport, sk, true);
182 if (IS_ERR(rt)) {
183 err = PTR_ERR(rt);
184 if (err == -ENETUNREACH)
185 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
186 return err;
187 }
188
189 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
190 ip_rt_put(rt);
191 return -ENETUNREACH;
192 }
193
194 if (!inet_opt || !inet_opt->opt.srr)
195 daddr = fl4->daddr;
196
197 if (!inet->inet_saddr)
198 inet->inet_saddr = fl4->saddr;
199 inet->inet_rcv_saddr = inet->inet_saddr;
200
201 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
202 /* Reset inherited state */
203 tp->rx_opt.ts_recent = 0;
204 tp->rx_opt.ts_recent_stamp = 0;
205 tp->write_seq = 0;
206 }
207
208 if (tcp_death_row.sysctl_tw_recycle &&
209 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
210 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
211 /*
212 * VJ's idea. We save last timestamp seen from
213 * the destination in peer table, when entering state
214 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
215 * when trying new connection.
216 */
217 if (peer) {
218 inet_peer_refcheck(peer);
219 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
220 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
221 tp->rx_opt.ts_recent = peer->tcp_ts;
222 }
223 }
224 }
225
226 inet->inet_dport = usin->sin_port;
227 inet->inet_daddr = daddr;
228
229 inet_csk(sk)->icsk_ext_hdr_len = 0;
230 if (inet_opt)
231 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
232
233 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
234
235 /* Socket identity is still unknown (sport may be zero).
236 * However we set state to SYN-SENT and not releasing socket
237 * lock select source port, enter ourselves into the hash tables and
238 * complete initialization after this.
239 */
240 tcp_set_state(sk, TCP_SYN_SENT);
241 err = inet_hash_connect(&tcp_death_row, sk);
242 if (err)
243 goto failure;
244
245 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
246 inet->inet_sport, inet->inet_dport, sk);
247 if (IS_ERR(rt)) {
248 err = PTR_ERR(rt);
249 rt = NULL;
250 goto failure;
251 }
252 /* OK, now commit destination to socket. */
253 sk->sk_gso_type = SKB_GSO_TCPV4;
254 sk_setup_caps(sk, &rt->dst);
255
256 if (!tp->write_seq)
257 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
258 inet->inet_daddr,
259 inet->inet_sport,
260 usin->sin_port);
261
262 inet->inet_id = tp->write_seq ^ jiffies;
263
264 err = tcp_connect(sk);
265 rt = NULL;
266 if (err)
267 goto failure;
268
269 return 0;
270
271 failure:
272 /*
273 * This unhashes the socket and releases the local port,
274 * if necessary.
275 */
276 tcp_set_state(sk, TCP_CLOSE);
277 ip_rt_put(rt);
278 sk->sk_route_caps = 0;
279 inet->inet_dport = 0;
280 return err;
281 }
282 EXPORT_SYMBOL(tcp_v4_connect);
283
284 /*
285 * This routine does path mtu discovery as defined in RFC1191.
286 */
287 static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
288 {
289 struct dst_entry *dst;
290 struct inet_sock *inet = inet_sk(sk);
291
292 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
293 * send out by Linux are always <576bytes so they should go through
294 * unfragmented).
295 */
296 if (sk->sk_state == TCP_LISTEN)
297 return;
298
299 /* We don't check in the destentry if pmtu discovery is forbidden
300 * on this route. We just assume that no packet_to_big packets
301 * are send back when pmtu discovery is not active.
302 * There is a small race when the user changes this flag in the
303 * route, but I think that's acceptable.
304 */
305 if ((dst = __sk_dst_check(sk, 0)) == NULL)
306 return;
307
308 dst->ops->update_pmtu(dst, mtu);
309
310 /* Something is about to be wrong... Remember soft error
311 * for the case, if this connection will not able to recover.
312 */
313 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
314 sk->sk_err_soft = EMSGSIZE;
315
316 mtu = dst_mtu(dst);
317
318 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
319 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
320 tcp_sync_mss(sk, mtu);
321
322 /* Resend the TCP packet because it's
323 * clear that the old packet has been
324 * dropped. This is the new "fast" path mtu
325 * discovery.
326 */
327 tcp_simple_retransmit(sk);
328 } /* else let the usual retransmit timer handle it */
329 }
330
331 /*
332 * This routine is called by the ICMP module when it gets some
333 * sort of error condition. If err < 0 then the socket should
334 * be closed and the error returned to the user. If err > 0
335 * it's just the icmp type << 8 | icmp code. After adjustment
336 * header points to the first 8 bytes of the tcp header. We need
337 * to find the appropriate port.
338 *
339 * The locking strategy used here is very "optimistic". When
340 * someone else accesses the socket the ICMP is just dropped
341 * and for some paths there is no check at all.
342 * A more general error queue to queue errors for later handling
343 * is probably better.
344 *
345 */
346
347 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
348 {
349 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
350 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
351 struct inet_connection_sock *icsk;
352 struct tcp_sock *tp;
353 struct inet_sock *inet;
354 const int type = icmp_hdr(icmp_skb)->type;
355 const int code = icmp_hdr(icmp_skb)->code;
356 struct sock *sk;
357 struct sk_buff *skb;
358 __u32 seq;
359 __u32 remaining;
360 int err;
361 struct net *net = dev_net(icmp_skb->dev);
362
363 if (icmp_skb->len < (iph->ihl << 2) + 8) {
364 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
365 return;
366 }
367
368 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
369 iph->saddr, th->source, inet_iif(icmp_skb));
370 if (!sk) {
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
372 return;
373 }
374 if (sk->sk_state == TCP_TIME_WAIT) {
375 inet_twsk_put(inet_twsk(sk));
376 return;
377 }
378
379 bh_lock_sock(sk);
380 /* If too many ICMPs get dropped on busy
381 * servers this needs to be solved differently.
382 */
383 if (sock_owned_by_user(sk))
384 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
385
386 if (sk->sk_state == TCP_CLOSE)
387 goto out;
388
389 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
390 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
391 goto out;
392 }
393
394 icsk = inet_csk(sk);
395 tp = tcp_sk(sk);
396 seq = ntohl(th->seq);
397 if (sk->sk_state != TCP_LISTEN &&
398 !between(seq, tp->snd_una, tp->snd_nxt)) {
399 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
400 goto out;
401 }
402
403 switch (type) {
404 case ICMP_SOURCE_QUENCH:
405 /* Just silently ignore these. */
406 goto out;
407 case ICMP_PARAMETERPROB:
408 err = EPROTO;
409 break;
410 case ICMP_DEST_UNREACH:
411 if (code > NR_ICMP_UNREACH)
412 goto out;
413
414 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
415 if (!sock_owned_by_user(sk))
416 do_pmtu_discovery(sk, iph, info);
417 goto out;
418 }
419
420 err = icmp_err_convert[code].errno;
421 /* check if icmp_skb allows revert of backoff
422 * (see draft-zimmermann-tcp-lcd) */
423 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
424 break;
425 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
426 !icsk->icsk_backoff)
427 break;
428
429 if (sock_owned_by_user(sk))
430 break;
431
432 icsk->icsk_backoff--;
433 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
434 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
435 tcp_bound_rto(sk);
436
437 skb = tcp_write_queue_head(sk);
438 BUG_ON(!skb);
439
440 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
441 tcp_time_stamp - TCP_SKB_CB(skb)->when);
442
443 if (remaining) {
444 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
445 remaining, TCP_RTO_MAX);
446 } else {
447 /* RTO revert clocked out retransmission.
448 * Will retransmit now */
449 tcp_retransmit_timer(sk);
450 }
451
452 break;
453 case ICMP_TIME_EXCEEDED:
454 err = EHOSTUNREACH;
455 break;
456 default:
457 goto out;
458 }
459
460 switch (sk->sk_state) {
461 struct request_sock *req, **prev;
462 case TCP_LISTEN:
463 if (sock_owned_by_user(sk))
464 goto out;
465
466 req = inet_csk_search_req(sk, &prev, th->dest,
467 iph->daddr, iph->saddr);
468 if (!req)
469 goto out;
470
471 /* ICMPs are not backlogged, hence we cannot get
472 an established socket here.
473 */
474 WARN_ON(req->sk);
475
476 if (seq != tcp_rsk(req)->snt_isn) {
477 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
478 goto out;
479 }
480
481 /*
482 * Still in SYN_RECV, just remove it silently.
483 * There is no good way to pass the error to the newly
484 * created socket, and POSIX does not want network
485 * errors returned from accept().
486 */
487 inet_csk_reqsk_queue_drop(sk, req, prev);
488 goto out;
489
490 case TCP_SYN_SENT:
491 case TCP_SYN_RECV: /* Cannot happen.
492 It can f.e. if SYNs crossed.
493 */
494 if (!sock_owned_by_user(sk)) {
495 sk->sk_err = err;
496
497 sk->sk_error_report(sk);
498
499 tcp_done(sk);
500 } else {
501 sk->sk_err_soft = err;
502 }
503 goto out;
504 }
505
506 /* If we've already connected we will keep trying
507 * until we time out, or the user gives up.
508 *
509 * rfc1122 4.2.3.9 allows to consider as hard errors
510 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
511 * but it is obsoleted by pmtu discovery).
512 *
513 * Note, that in modern internet, where routing is unreliable
514 * and in each dark corner broken firewalls sit, sending random
515 * errors ordered by their masters even this two messages finally lose
516 * their original sense (even Linux sends invalid PORT_UNREACHs)
517 *
518 * Now we are in compliance with RFCs.
519 * --ANK (980905)
520 */
521
522 inet = inet_sk(sk);
523 if (!sock_owned_by_user(sk) && inet->recverr) {
524 sk->sk_err = err;
525 sk->sk_error_report(sk);
526 } else { /* Only an error on timeout */
527 sk->sk_err_soft = err;
528 }
529
530 out:
531 bh_unlock_sock(sk);
532 sock_put(sk);
533 }
534
535 static void __tcp_v4_send_check(struct sk_buff *skb,
536 __be32 saddr, __be32 daddr)
537 {
538 struct tcphdr *th = tcp_hdr(skb);
539
540 if (skb->ip_summed == CHECKSUM_PARTIAL) {
541 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
542 skb->csum_start = skb_transport_header(skb) - skb->head;
543 skb->csum_offset = offsetof(struct tcphdr, check);
544 } else {
545 th->check = tcp_v4_check(skb->len, saddr, daddr,
546 csum_partial(th,
547 th->doff << 2,
548 skb->csum));
549 }
550 }
551
552 /* This routine computes an IPv4 TCP checksum. */
553 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
554 {
555 struct inet_sock *inet = inet_sk(sk);
556
557 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
558 }
559 EXPORT_SYMBOL(tcp_v4_send_check);
560
561 int tcp_v4_gso_send_check(struct sk_buff *skb)
562 {
563 const struct iphdr *iph;
564 struct tcphdr *th;
565
566 if (!pskb_may_pull(skb, sizeof(*th)))
567 return -EINVAL;
568
569 iph = ip_hdr(skb);
570 th = tcp_hdr(skb);
571
572 th->check = 0;
573 skb->ip_summed = CHECKSUM_PARTIAL;
574 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
575 return 0;
576 }
577
578 /*
579 * This routine will send an RST to the other tcp.
580 *
581 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
582 * for reset.
583 * Answer: if a packet caused RST, it is not for a socket
584 * existing in our system, if it is matched to a socket,
585 * it is just duplicate segment or bug in other side's TCP.
586 * So that we build reply only basing on parameters
587 * arrived with segment.
588 * Exception: precedence violation. We do not implement it in any case.
589 */
590
591 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
592 {
593 struct tcphdr *th = tcp_hdr(skb);
594 struct {
595 struct tcphdr th;
596 #ifdef CONFIG_TCP_MD5SIG
597 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
598 #endif
599 } rep;
600 struct ip_reply_arg arg;
601 #ifdef CONFIG_TCP_MD5SIG
602 struct tcp_md5sig_key *key;
603 #endif
604 struct net *net;
605
606 /* Never send a reset in response to a reset. */
607 if (th->rst)
608 return;
609
610 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
611 return;
612
613 /* Swap the send and the receive. */
614 memset(&rep, 0, sizeof(rep));
615 rep.th.dest = th->source;
616 rep.th.source = th->dest;
617 rep.th.doff = sizeof(struct tcphdr) / 4;
618 rep.th.rst = 1;
619
620 if (th->ack) {
621 rep.th.seq = th->ack_seq;
622 } else {
623 rep.th.ack = 1;
624 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
625 skb->len - (th->doff << 2));
626 }
627
628 memset(&arg, 0, sizeof(arg));
629 arg.iov[0].iov_base = (unsigned char *)&rep;
630 arg.iov[0].iov_len = sizeof(rep.th);
631
632 #ifdef CONFIG_TCP_MD5SIG
633 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
634 if (key) {
635 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
636 (TCPOPT_NOP << 16) |
637 (TCPOPT_MD5SIG << 8) |
638 TCPOLEN_MD5SIG);
639 /* Update length and the length the header thinks exists */
640 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
641 rep.th.doff = arg.iov[0].iov_len / 4;
642
643 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
644 key, ip_hdr(skb)->saddr,
645 ip_hdr(skb)->daddr, &rep.th);
646 }
647 #endif
648 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
649 ip_hdr(skb)->saddr, /* XXX */
650 arg.iov[0].iov_len, IPPROTO_TCP, 0);
651 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
652 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
653
654 net = dev_net(skb_dst(skb)->dev);
655 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
656 &arg, arg.iov[0].iov_len);
657
658 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
659 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
660 }
661
662 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
663 outside socket context is ugly, certainly. What can I do?
664 */
665
666 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
667 u32 win, u32 ts, int oif,
668 struct tcp_md5sig_key *key,
669 int reply_flags)
670 {
671 struct tcphdr *th = tcp_hdr(skb);
672 struct {
673 struct tcphdr th;
674 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
675 #ifdef CONFIG_TCP_MD5SIG
676 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
677 #endif
678 ];
679 } rep;
680 struct ip_reply_arg arg;
681 struct net *net = dev_net(skb_dst(skb)->dev);
682
683 memset(&rep.th, 0, sizeof(struct tcphdr));
684 memset(&arg, 0, sizeof(arg));
685
686 arg.iov[0].iov_base = (unsigned char *)&rep;
687 arg.iov[0].iov_len = sizeof(rep.th);
688 if (ts) {
689 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
690 (TCPOPT_TIMESTAMP << 8) |
691 TCPOLEN_TIMESTAMP);
692 rep.opt[1] = htonl(tcp_time_stamp);
693 rep.opt[2] = htonl(ts);
694 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
695 }
696
697 /* Swap the send and the receive. */
698 rep.th.dest = th->source;
699 rep.th.source = th->dest;
700 rep.th.doff = arg.iov[0].iov_len / 4;
701 rep.th.seq = htonl(seq);
702 rep.th.ack_seq = htonl(ack);
703 rep.th.ack = 1;
704 rep.th.window = htons(win);
705
706 #ifdef CONFIG_TCP_MD5SIG
707 if (key) {
708 int offset = (ts) ? 3 : 0;
709
710 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
711 (TCPOPT_NOP << 16) |
712 (TCPOPT_MD5SIG << 8) |
713 TCPOLEN_MD5SIG);
714 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
715 rep.th.doff = arg.iov[0].iov_len/4;
716
717 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
718 key, ip_hdr(skb)->saddr,
719 ip_hdr(skb)->daddr, &rep.th);
720 }
721 #endif
722 arg.flags = reply_flags;
723 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
724 ip_hdr(skb)->saddr, /* XXX */
725 arg.iov[0].iov_len, IPPROTO_TCP, 0);
726 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
727 if (oif)
728 arg.bound_dev_if = oif;
729
730 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
731 &arg, arg.iov[0].iov_len);
732
733 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
734 }
735
736 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
737 {
738 struct inet_timewait_sock *tw = inet_twsk(sk);
739 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
740
741 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
742 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
743 tcptw->tw_ts_recent,
744 tw->tw_bound_dev_if,
745 tcp_twsk_md5_key(tcptw),
746 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
747 );
748
749 inet_twsk_put(tw);
750 }
751
752 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
753 struct request_sock *req)
754 {
755 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
756 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
757 req->ts_recent,
758 0,
759 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
760 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
761 }
762
763 /*
764 * Send a SYN-ACK after having received a SYN.
765 * This still operates on a request_sock only, not on a big
766 * socket.
767 */
768 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
769 struct request_sock *req,
770 struct request_values *rvp)
771 {
772 const struct inet_request_sock *ireq = inet_rsk(req);
773 struct flowi4 fl4;
774 int err = -1;
775 struct sk_buff * skb;
776
777 /* First, grab a route. */
778 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
779 return -1;
780
781 skb = tcp_make_synack(sk, dst, req, rvp);
782
783 if (skb) {
784 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
785
786 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
787 ireq->rmt_addr,
788 ireq->opt);
789 err = net_xmit_eval(err);
790 }
791
792 dst_release(dst);
793 return err;
794 }
795
796 static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
797 struct request_values *rvp)
798 {
799 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
800 return tcp_v4_send_synack(sk, NULL, req, rvp);
801 }
802
803 /*
804 * IPv4 request_sock destructor.
805 */
806 static void tcp_v4_reqsk_destructor(struct request_sock *req)
807 {
808 kfree(inet_rsk(req)->opt);
809 }
810
811 /*
812 * Return 1 if a syncookie should be sent
813 */
814 int tcp_syn_flood_action(struct sock *sk,
815 const struct sk_buff *skb,
816 const char *proto)
817 {
818 const char *msg = "Dropping request";
819 int want_cookie = 0;
820 struct listen_sock *lopt;
821
822
823
824 #ifdef CONFIG_SYN_COOKIES
825 if (sysctl_tcp_syncookies) {
826 msg = "Sending cookies";
827 want_cookie = 1;
828 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
829 } else
830 #endif
831 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
832
833 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
834 if (!lopt->synflood_warned) {
835 lopt->synflood_warned = 1;
836 pr_info("%s: Possible SYN flooding on port %d. %s. "
837 " Check SNMP counters.\n",
838 proto, ntohs(tcp_hdr(skb)->dest), msg);
839 }
840 return want_cookie;
841 }
842 EXPORT_SYMBOL(tcp_syn_flood_action);
843
844 /*
845 * Save and compile IPv4 options into the request_sock if needed.
846 */
847 static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
848 struct sk_buff *skb)
849 {
850 const struct ip_options *opt = &(IPCB(skb)->opt);
851 struct ip_options_rcu *dopt = NULL;
852
853 if (opt && opt->optlen) {
854 int opt_size = sizeof(*dopt) + opt->optlen;
855
856 dopt = kmalloc(opt_size, GFP_ATOMIC);
857 if (dopt) {
858 if (ip_options_echo(&dopt->opt, skb)) {
859 kfree(dopt);
860 dopt = NULL;
861 }
862 }
863 }
864 return dopt;
865 }
866
867 #ifdef CONFIG_TCP_MD5SIG
868 /*
869 * RFC2385 MD5 checksumming requires a mapping of
870 * IP address->MD5 Key.
871 * We need to maintain these in the sk structure.
872 */
873
874 /* Find the Key structure for an address. */
875 static struct tcp_md5sig_key *
876 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
877 {
878 struct tcp_sock *tp = tcp_sk(sk);
879 int i;
880
881 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
882 return NULL;
883 for (i = 0; i < tp->md5sig_info->entries4; i++) {
884 if (tp->md5sig_info->keys4[i].addr == addr)
885 return &tp->md5sig_info->keys4[i].base;
886 }
887 return NULL;
888 }
889
890 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
891 struct sock *addr_sk)
892 {
893 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
894 }
895 EXPORT_SYMBOL(tcp_v4_md5_lookup);
896
897 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
898 struct request_sock *req)
899 {
900 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
901 }
902
903 /* This can be called on a newly created socket, from other files */
904 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
905 u8 *newkey, u8 newkeylen)
906 {
907 /* Add Key to the list */
908 struct tcp_md5sig_key *key;
909 struct tcp_sock *tp = tcp_sk(sk);
910 struct tcp4_md5sig_key *keys;
911
912 key = tcp_v4_md5_do_lookup(sk, addr);
913 if (key) {
914 /* Pre-existing entry - just update that one. */
915 kfree(key->key);
916 key->key = newkey;
917 key->keylen = newkeylen;
918 } else {
919 struct tcp_md5sig_info *md5sig;
920
921 if (!tp->md5sig_info) {
922 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
923 GFP_ATOMIC);
924 if (!tp->md5sig_info) {
925 kfree(newkey);
926 return -ENOMEM;
927 }
928 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
929 }
930 if (tcp_alloc_md5sig_pool(sk) == NULL) {
931 kfree(newkey);
932 return -ENOMEM;
933 }
934 md5sig = tp->md5sig_info;
935
936 if (md5sig->alloced4 == md5sig->entries4) {
937 keys = kmalloc((sizeof(*keys) *
938 (md5sig->entries4 + 1)), GFP_ATOMIC);
939 if (!keys) {
940 kfree(newkey);
941 tcp_free_md5sig_pool();
942 return -ENOMEM;
943 }
944
945 if (md5sig->entries4)
946 memcpy(keys, md5sig->keys4,
947 sizeof(*keys) * md5sig->entries4);
948
949 /* Free old key list, and reference new one */
950 kfree(md5sig->keys4);
951 md5sig->keys4 = keys;
952 md5sig->alloced4++;
953 }
954 md5sig->entries4++;
955 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
956 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
957 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
958 }
959 return 0;
960 }
961 EXPORT_SYMBOL(tcp_v4_md5_do_add);
962
963 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
964 u8 *newkey, u8 newkeylen)
965 {
966 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
967 newkey, newkeylen);
968 }
969
970 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
971 {
972 struct tcp_sock *tp = tcp_sk(sk);
973 int i;
974
975 for (i = 0; i < tp->md5sig_info->entries4; i++) {
976 if (tp->md5sig_info->keys4[i].addr == addr) {
977 /* Free the key */
978 kfree(tp->md5sig_info->keys4[i].base.key);
979 tp->md5sig_info->entries4--;
980
981 if (tp->md5sig_info->entries4 == 0) {
982 kfree(tp->md5sig_info->keys4);
983 tp->md5sig_info->keys4 = NULL;
984 tp->md5sig_info->alloced4 = 0;
985 } else if (tp->md5sig_info->entries4 != i) {
986 /* Need to do some manipulation */
987 memmove(&tp->md5sig_info->keys4[i],
988 &tp->md5sig_info->keys4[i+1],
989 (tp->md5sig_info->entries4 - i) *
990 sizeof(struct tcp4_md5sig_key));
991 }
992 tcp_free_md5sig_pool();
993 return 0;
994 }
995 }
996 return -ENOENT;
997 }
998 EXPORT_SYMBOL(tcp_v4_md5_do_del);
999
1000 static void tcp_v4_clear_md5_list(struct sock *sk)
1001 {
1002 struct tcp_sock *tp = tcp_sk(sk);
1003
1004 /* Free each key, then the set of key keys,
1005 * the crypto element, and then decrement our
1006 * hold on the last resort crypto.
1007 */
1008 if (tp->md5sig_info->entries4) {
1009 int i;
1010 for (i = 0; i < tp->md5sig_info->entries4; i++)
1011 kfree(tp->md5sig_info->keys4[i].base.key);
1012 tp->md5sig_info->entries4 = 0;
1013 tcp_free_md5sig_pool();
1014 }
1015 if (tp->md5sig_info->keys4) {
1016 kfree(tp->md5sig_info->keys4);
1017 tp->md5sig_info->keys4 = NULL;
1018 tp->md5sig_info->alloced4 = 0;
1019 }
1020 }
1021
1022 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1023 int optlen)
1024 {
1025 struct tcp_md5sig cmd;
1026 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1027 u8 *newkey;
1028
1029 if (optlen < sizeof(cmd))
1030 return -EINVAL;
1031
1032 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1033 return -EFAULT;
1034
1035 if (sin->sin_family != AF_INET)
1036 return -EINVAL;
1037
1038 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
1039 if (!tcp_sk(sk)->md5sig_info)
1040 return -ENOENT;
1041 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
1042 }
1043
1044 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1045 return -EINVAL;
1046
1047 if (!tcp_sk(sk)->md5sig_info) {
1048 struct tcp_sock *tp = tcp_sk(sk);
1049 struct tcp_md5sig_info *p;
1050
1051 p = kzalloc(sizeof(*p), sk->sk_allocation);
1052 if (!p)
1053 return -EINVAL;
1054
1055 tp->md5sig_info = p;
1056 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1057 }
1058
1059 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1060 if (!newkey)
1061 return -ENOMEM;
1062 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1063 newkey, cmd.tcpm_keylen);
1064 }
1065
1066 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1067 __be32 daddr, __be32 saddr, int nbytes)
1068 {
1069 struct tcp4_pseudohdr *bp;
1070 struct scatterlist sg;
1071
1072 bp = &hp->md5_blk.ip4;
1073
1074 /*
1075 * 1. the TCP pseudo-header (in the order: source IP address,
1076 * destination IP address, zero-padded protocol number, and
1077 * segment length)
1078 */
1079 bp->saddr = saddr;
1080 bp->daddr = daddr;
1081 bp->pad = 0;
1082 bp->protocol = IPPROTO_TCP;
1083 bp->len = cpu_to_be16(nbytes);
1084
1085 sg_init_one(&sg, bp, sizeof(*bp));
1086 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1087 }
1088
1089 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1090 __be32 daddr, __be32 saddr, struct tcphdr *th)
1091 {
1092 struct tcp_md5sig_pool *hp;
1093 struct hash_desc *desc;
1094
1095 hp = tcp_get_md5sig_pool();
1096 if (!hp)
1097 goto clear_hash_noput;
1098 desc = &hp->md5_desc;
1099
1100 if (crypto_hash_init(desc))
1101 goto clear_hash;
1102 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1103 goto clear_hash;
1104 if (tcp_md5_hash_header(hp, th))
1105 goto clear_hash;
1106 if (tcp_md5_hash_key(hp, key))
1107 goto clear_hash;
1108 if (crypto_hash_final(desc, md5_hash))
1109 goto clear_hash;
1110
1111 tcp_put_md5sig_pool();
1112 return 0;
1113
1114 clear_hash:
1115 tcp_put_md5sig_pool();
1116 clear_hash_noput:
1117 memset(md5_hash, 0, 16);
1118 return 1;
1119 }
1120
1121 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1122 struct sock *sk, struct request_sock *req,
1123 struct sk_buff *skb)
1124 {
1125 struct tcp_md5sig_pool *hp;
1126 struct hash_desc *desc;
1127 struct tcphdr *th = tcp_hdr(skb);
1128 __be32 saddr, daddr;
1129
1130 if (sk) {
1131 saddr = inet_sk(sk)->inet_saddr;
1132 daddr = inet_sk(sk)->inet_daddr;
1133 } else if (req) {
1134 saddr = inet_rsk(req)->loc_addr;
1135 daddr = inet_rsk(req)->rmt_addr;
1136 } else {
1137 const struct iphdr *iph = ip_hdr(skb);
1138 saddr = iph->saddr;
1139 daddr = iph->daddr;
1140 }
1141
1142 hp = tcp_get_md5sig_pool();
1143 if (!hp)
1144 goto clear_hash_noput;
1145 desc = &hp->md5_desc;
1146
1147 if (crypto_hash_init(desc))
1148 goto clear_hash;
1149
1150 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1151 goto clear_hash;
1152 if (tcp_md5_hash_header(hp, th))
1153 goto clear_hash;
1154 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1155 goto clear_hash;
1156 if (tcp_md5_hash_key(hp, key))
1157 goto clear_hash;
1158 if (crypto_hash_final(desc, md5_hash))
1159 goto clear_hash;
1160
1161 tcp_put_md5sig_pool();
1162 return 0;
1163
1164 clear_hash:
1165 tcp_put_md5sig_pool();
1166 clear_hash_noput:
1167 memset(md5_hash, 0, 16);
1168 return 1;
1169 }
1170 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1171
1172 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1173 {
1174 /*
1175 * This gets called for each TCP segment that arrives
1176 * so we want to be efficient.
1177 * We have 3 drop cases:
1178 * o No MD5 hash and one expected.
1179 * o MD5 hash and we're not expecting one.
1180 * o MD5 hash and its wrong.
1181 */
1182 __u8 *hash_location = NULL;
1183 struct tcp_md5sig_key *hash_expected;
1184 const struct iphdr *iph = ip_hdr(skb);
1185 struct tcphdr *th = tcp_hdr(skb);
1186 int genhash;
1187 unsigned char newhash[16];
1188
1189 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1190 hash_location = tcp_parse_md5sig_option(th);
1191
1192 /* We've parsed the options - do we have a hash? */
1193 if (!hash_expected && !hash_location)
1194 return 0;
1195
1196 if (hash_expected && !hash_location) {
1197 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1198 return 1;
1199 }
1200
1201 if (!hash_expected && hash_location) {
1202 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1203 return 1;
1204 }
1205
1206 /* Okay, so this is hash_expected and hash_location -
1207 * so we need to calculate the checksum.
1208 */
1209 genhash = tcp_v4_md5_hash_skb(newhash,
1210 hash_expected,
1211 NULL, NULL, skb);
1212
1213 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1214 if (net_ratelimit()) {
1215 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1216 &iph->saddr, ntohs(th->source),
1217 &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_rtx_synack,
1231 .send_ack = tcp_v4_reqsk_send_ack,
1232 .destructor = tcp_v4_reqsk_destructor,
1233 .send_reset = tcp_v4_send_reset,
1234 .syn_ack_timeout = tcp_syn_ack_timeout,
1235 };
1236
1237 #ifdef CONFIG_TCP_MD5SIG
1238 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1239 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1240 .calc_md5_hash = tcp_v4_md5_hash_skb,
1241 };
1242 #endif
1243
1244 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1245 {
1246 struct tcp_extend_values tmp_ext;
1247 struct tcp_options_received tmp_opt;
1248 u8 *hash_location;
1249 struct request_sock *req;
1250 struct inet_request_sock *ireq;
1251 struct tcp_sock *tp = tcp_sk(sk);
1252 struct dst_entry *dst = NULL;
1253 __be32 saddr = ip_hdr(skb)->saddr;
1254 __be32 daddr = ip_hdr(skb)->daddr;
1255 __u32 isn = TCP_SKB_CB(skb)->when;
1256 int want_cookie = 0;
1257
1258 /* Never answer to SYNs send to broadcast or multicast */
1259 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1260 goto drop;
1261
1262 /* TW buckets are converted to open requests without
1263 * limitations, they conserve resources and peer is
1264 * evidently real one.
1265 */
1266 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1267 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1268 if (!want_cookie)
1269 goto drop;
1270 }
1271
1272 /* Accept backlog is full. If we have already queued enough
1273 * of warm entries in syn queue, drop request. It is better than
1274 * clogging syn queue with openreqs with exponentially increasing
1275 * timeout.
1276 */
1277 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1278 goto drop;
1279
1280 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1281 if (!req)
1282 goto drop;
1283
1284 #ifdef CONFIG_TCP_MD5SIG
1285 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1286 #endif
1287
1288 tcp_clear_options(&tmp_opt);
1289 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1290 tmp_opt.user_mss = tp->rx_opt.user_mss;
1291 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1292
1293 if (tmp_opt.cookie_plus > 0 &&
1294 tmp_opt.saw_tstamp &&
1295 !tp->rx_opt.cookie_out_never &&
1296 (sysctl_tcp_cookie_size > 0 ||
1297 (tp->cookie_values != NULL &&
1298 tp->cookie_values->cookie_desired > 0))) {
1299 u8 *c;
1300 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1301 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1302
1303 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1304 goto drop_and_release;
1305
1306 /* Secret recipe starts with IP addresses */
1307 *mess++ ^= (__force u32)daddr;
1308 *mess++ ^= (__force u32)saddr;
1309
1310 /* plus variable length Initiator Cookie */
1311 c = (u8 *)mess;
1312 while (l-- > 0)
1313 *c++ ^= *hash_location++;
1314
1315 want_cookie = 0; /* not our kind of cookie */
1316 tmp_ext.cookie_out_never = 0; /* false */
1317 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1318 } else if (!tp->rx_opt.cookie_in_always) {
1319 /* redundant indications, but ensure initialization. */
1320 tmp_ext.cookie_out_never = 1; /* true */
1321 tmp_ext.cookie_plus = 0;
1322 } else {
1323 goto drop_and_release;
1324 }
1325 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1326
1327 if (want_cookie && !tmp_opt.saw_tstamp)
1328 tcp_clear_options(&tmp_opt);
1329
1330 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1331 tcp_openreq_init(req, &tmp_opt, skb);
1332
1333 ireq = inet_rsk(req);
1334 ireq->loc_addr = daddr;
1335 ireq->rmt_addr = saddr;
1336 ireq->no_srccheck = inet_sk(sk)->transparent;
1337 ireq->opt = tcp_v4_save_options(sk, skb);
1338
1339 if (security_inet_conn_request(sk, skb, req))
1340 goto drop_and_free;
1341
1342 if (!want_cookie || tmp_opt.tstamp_ok)
1343 TCP_ECN_create_request(req, tcp_hdr(skb));
1344
1345 if (want_cookie) {
1346 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1347 req->cookie_ts = tmp_opt.tstamp_ok;
1348 } else if (!isn) {
1349 struct inet_peer *peer = NULL;
1350 struct flowi4 fl4;
1351
1352 /* VJ's idea. We save last timestamp seen
1353 * from the destination in peer table, when entering
1354 * state TIME-WAIT, and check against it before
1355 * accepting new connection request.
1356 *
1357 * If "isn" is not zero, this request hit alive
1358 * timewait bucket, so that all the necessary checks
1359 * are made in the function processing timewait state.
1360 */
1361 if (tmp_opt.saw_tstamp &&
1362 tcp_death_row.sysctl_tw_recycle &&
1363 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1364 fl4.daddr == saddr &&
1365 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1366 inet_peer_refcheck(peer);
1367 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1368 (s32)(peer->tcp_ts - req->ts_recent) >
1369 TCP_PAWS_WINDOW) {
1370 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1371 goto drop_and_release;
1372 }
1373 }
1374 /* Kill the following clause, if you dislike this way. */
1375 else if (!sysctl_tcp_syncookies &&
1376 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1377 (sysctl_max_syn_backlog >> 2)) &&
1378 (!peer || !peer->tcp_ts_stamp) &&
1379 (!dst || !dst_metric(dst, RTAX_RTT))) {
1380 /* Without syncookies last quarter of
1381 * backlog is filled with destinations,
1382 * proven to be alive.
1383 * It means that we continue to communicate
1384 * to destinations, already remembered
1385 * to the moment of synflood.
1386 */
1387 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1388 &saddr, ntohs(tcp_hdr(skb)->source));
1389 goto drop_and_release;
1390 }
1391
1392 isn = tcp_v4_init_sequence(skb);
1393 }
1394 tcp_rsk(req)->snt_isn = isn;
1395 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1396
1397 if (tcp_v4_send_synack(sk, dst, req,
1398 (struct request_values *)&tmp_ext) ||
1399 want_cookie)
1400 goto drop_and_free;
1401
1402 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1403 return 0;
1404
1405 drop_and_release:
1406 dst_release(dst);
1407 drop_and_free:
1408 reqsk_free(req);
1409 drop:
1410 return 0;
1411 }
1412 EXPORT_SYMBOL(tcp_v4_conn_request);
1413
1414
1415 /*
1416 * The three way handshake has completed - we got a valid synack -
1417 * now create the new socket.
1418 */
1419 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1420 struct request_sock *req,
1421 struct dst_entry *dst)
1422 {
1423 struct inet_request_sock *ireq;
1424 struct inet_sock *newinet;
1425 struct tcp_sock *newtp;
1426 struct sock *newsk;
1427 #ifdef CONFIG_TCP_MD5SIG
1428 struct tcp_md5sig_key *key;
1429 #endif
1430 struct ip_options_rcu *inet_opt;
1431
1432 if (sk_acceptq_is_full(sk))
1433 goto exit_overflow;
1434
1435 newsk = tcp_create_openreq_child(sk, req, skb);
1436 if (!newsk)
1437 goto exit_nonewsk;
1438
1439 newsk->sk_gso_type = SKB_GSO_TCPV4;
1440
1441 newtp = tcp_sk(newsk);
1442 newinet = inet_sk(newsk);
1443 ireq = inet_rsk(req);
1444 newinet->inet_daddr = ireq->rmt_addr;
1445 newinet->inet_rcv_saddr = ireq->loc_addr;
1446 newinet->inet_saddr = ireq->loc_addr;
1447 inet_opt = ireq->opt;
1448 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1449 ireq->opt = NULL;
1450 newinet->mc_index = inet_iif(skb);
1451 newinet->mc_ttl = ip_hdr(skb)->ttl;
1452 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1453 if (inet_opt)
1454 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1455 newinet->inet_id = newtp->write_seq ^ jiffies;
1456
1457 if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
1458 goto put_and_exit;
1459
1460 sk_setup_caps(newsk, dst);
1461
1462 tcp_mtup_init(newsk);
1463 tcp_sync_mss(newsk, dst_mtu(dst));
1464 newtp->advmss = dst_metric_advmss(dst);
1465 if (tcp_sk(sk)->rx_opt.user_mss &&
1466 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1467 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1468
1469 tcp_initialize_rcv_mss(newsk);
1470 if (tcp_rsk(req)->snt_synack)
1471 tcp_valid_rtt_meas(newsk,
1472 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1473 newtp->total_retrans = req->retrans;
1474
1475 #ifdef CONFIG_TCP_MD5SIG
1476 /* Copy over the MD5 key from the original socket */
1477 key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
1478 if (key != NULL) {
1479 /*
1480 * We're using one, so create a matching key
1481 * on the newsk structure. If we fail to get
1482 * memory, then we end up not copying the key
1483 * across. Shucks.
1484 */
1485 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1486 if (newkey != NULL)
1487 tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1488 newkey, key->keylen);
1489 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1490 }
1491 #endif
1492
1493 if (__inet_inherit_port(sk, newsk) < 0)
1494 goto put_and_exit;
1495 __inet_hash_nolisten(newsk, NULL);
1496
1497 return newsk;
1498
1499 exit_overflow:
1500 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1501 exit_nonewsk:
1502 dst_release(dst);
1503 exit:
1504 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1505 return NULL;
1506 put_and_exit:
1507 sock_put(newsk);
1508 goto exit;
1509 }
1510 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1511
1512 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1513 {
1514 struct tcphdr *th = tcp_hdr(skb);
1515 const struct iphdr *iph = ip_hdr(skb);
1516 struct sock *nsk;
1517 struct request_sock **prev;
1518 /* Find possible connection requests. */
1519 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1520 iph->saddr, iph->daddr);
1521 if (req)
1522 return tcp_check_req(sk, skb, req, prev);
1523
1524 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1525 th->source, iph->daddr, th->dest, inet_iif(skb));
1526
1527 if (nsk) {
1528 if (nsk->sk_state != TCP_TIME_WAIT) {
1529 bh_lock_sock(nsk);
1530 return nsk;
1531 }
1532 inet_twsk_put(inet_twsk(nsk));
1533 return NULL;
1534 }
1535
1536 #ifdef CONFIG_SYN_COOKIES
1537 if (!th->syn)
1538 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1539 #endif
1540 return sk;
1541 }
1542
1543 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1544 {
1545 const struct iphdr *iph = ip_hdr(skb);
1546
1547 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1548 if (!tcp_v4_check(skb->len, iph->saddr,
1549 iph->daddr, skb->csum)) {
1550 skb->ip_summed = CHECKSUM_UNNECESSARY;
1551 return 0;
1552 }
1553 }
1554
1555 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1556 skb->len, IPPROTO_TCP, 0);
1557
1558 if (skb->len <= 76) {
1559 return __skb_checksum_complete(skb);
1560 }
1561 return 0;
1562 }
1563
1564
1565 /* The socket must have it's spinlock held when we get
1566 * here.
1567 *
1568 * We have a potential double-lock case here, so even when
1569 * doing backlog processing we use the BH locking scheme.
1570 * This is because we cannot sleep with the original spinlock
1571 * held.
1572 */
1573 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1574 {
1575 struct sock *rsk;
1576 #ifdef CONFIG_TCP_MD5SIG
1577 /*
1578 * We really want to reject the packet as early as possible
1579 * if:
1580 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1581 * o There is an MD5 option and we're not expecting one
1582 */
1583 if (tcp_v4_inbound_md5_hash(sk, skb))
1584 goto discard;
1585 #endif
1586
1587 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1588 sock_rps_save_rxhash(sk, skb->rxhash);
1589 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1590 rsk = sk;
1591 goto reset;
1592 }
1593 return 0;
1594 }
1595
1596 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1597 goto csum_err;
1598
1599 if (sk->sk_state == TCP_LISTEN) {
1600 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1601 if (!nsk)
1602 goto discard;
1603
1604 if (nsk != sk) {
1605 sock_rps_save_rxhash(nsk, skb->rxhash);
1606 if (tcp_child_process(sk, nsk, skb)) {
1607 rsk = nsk;
1608 goto reset;
1609 }
1610 return 0;
1611 }
1612 } else
1613 sock_rps_save_rxhash(sk, skb->rxhash);
1614
1615 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1616 rsk = sk;
1617 goto reset;
1618 }
1619 return 0;
1620
1621 reset:
1622 tcp_v4_send_reset(rsk, skb);
1623 discard:
1624 kfree_skb(skb);
1625 /* Be careful here. If this function gets more complicated and
1626 * gcc suffers from register pressure on the x86, sk (in %ebx)
1627 * might be destroyed here. This current version compiles correctly,
1628 * but you have been warned.
1629 */
1630 return 0;
1631
1632 csum_err:
1633 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1634 goto discard;
1635 }
1636 EXPORT_SYMBOL(tcp_v4_do_rcv);
1637
1638 /*
1639 * From tcp_input.c
1640 */
1641
1642 int tcp_v4_rcv(struct sk_buff *skb)
1643 {
1644 const struct iphdr *iph;
1645 struct tcphdr *th;
1646 struct sock *sk;
1647 int ret;
1648 struct net *net = dev_net(skb->dev);
1649
1650 if (skb->pkt_type != PACKET_HOST)
1651 goto discard_it;
1652
1653 /* Count it even if it's bad */
1654 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1655
1656 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1657 goto discard_it;
1658
1659 th = tcp_hdr(skb);
1660
1661 if (th->doff < sizeof(struct tcphdr) / 4)
1662 goto bad_packet;
1663 if (!pskb_may_pull(skb, th->doff * 4))
1664 goto discard_it;
1665
1666 /* An explanation is required here, I think.
1667 * Packet length and doff are validated by header prediction,
1668 * provided case of th->doff==0 is eliminated.
1669 * So, we defer the checks. */
1670 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1671 goto bad_packet;
1672
1673 th = tcp_hdr(skb);
1674 iph = ip_hdr(skb);
1675 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1676 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1677 skb->len - th->doff * 4);
1678 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1679 TCP_SKB_CB(skb)->when = 0;
1680 TCP_SKB_CB(skb)->flags = iph->tos;
1681 TCP_SKB_CB(skb)->sacked = 0;
1682
1683 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1684 if (!sk)
1685 goto no_tcp_socket;
1686
1687 process:
1688 if (sk->sk_state == TCP_TIME_WAIT)
1689 goto do_time_wait;
1690
1691 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1692 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1693 goto discard_and_relse;
1694 }
1695
1696 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1697 goto discard_and_relse;
1698 nf_reset(skb);
1699
1700 if (sk_filter(sk, skb))
1701 goto discard_and_relse;
1702
1703 skb->dev = NULL;
1704
1705 bh_lock_sock_nested(sk);
1706 ret = 0;
1707 if (!sock_owned_by_user(sk)) {
1708 #ifdef CONFIG_NET_DMA
1709 struct tcp_sock *tp = tcp_sk(sk);
1710 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1711 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1712 if (tp->ucopy.dma_chan)
1713 ret = tcp_v4_do_rcv(sk, skb);
1714 else
1715 #endif
1716 {
1717 if (!tcp_prequeue(sk, skb))
1718 ret = tcp_v4_do_rcv(sk, skb);
1719 }
1720 } else if (unlikely(sk_add_backlog(sk, skb))) {
1721 bh_unlock_sock(sk);
1722 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1723 goto discard_and_relse;
1724 }
1725 bh_unlock_sock(sk);
1726
1727 sock_put(sk);
1728
1729 return ret;
1730
1731 no_tcp_socket:
1732 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1733 goto discard_it;
1734
1735 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1736 bad_packet:
1737 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1738 } else {
1739 tcp_v4_send_reset(NULL, skb);
1740 }
1741
1742 discard_it:
1743 /* Discard frame. */
1744 kfree_skb(skb);
1745 return 0;
1746
1747 discard_and_relse:
1748 sock_put(sk);
1749 goto discard_it;
1750
1751 do_time_wait:
1752 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1753 inet_twsk_put(inet_twsk(sk));
1754 goto discard_it;
1755 }
1756
1757 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1758 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1759 inet_twsk_put(inet_twsk(sk));
1760 goto discard_it;
1761 }
1762 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1763 case TCP_TW_SYN: {
1764 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1765 &tcp_hashinfo,
1766 iph->daddr, th->dest,
1767 inet_iif(skb));
1768 if (sk2) {
1769 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1770 inet_twsk_put(inet_twsk(sk));
1771 sk = sk2;
1772 goto process;
1773 }
1774 /* Fall through to ACK */
1775 }
1776 case TCP_TW_ACK:
1777 tcp_v4_timewait_ack(sk, skb);
1778 break;
1779 case TCP_TW_RST:
1780 goto no_tcp_socket;
1781 case TCP_TW_SUCCESS:;
1782 }
1783 goto discard_it;
1784 }
1785
1786 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1787 {
1788 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1789 struct inet_sock *inet = inet_sk(sk);
1790 struct inet_peer *peer;
1791
1792 if (!rt ||
1793 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1794 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1795 *release_it = true;
1796 } else {
1797 if (!rt->peer)
1798 rt_bind_peer(rt, inet->inet_daddr, 1);
1799 peer = rt->peer;
1800 *release_it = false;
1801 }
1802
1803 return peer;
1804 }
1805 EXPORT_SYMBOL(tcp_v4_get_peer);
1806
1807 void *tcp_v4_tw_get_peer(struct sock *sk)
1808 {
1809 struct inet_timewait_sock *tw = inet_twsk(sk);
1810
1811 return inet_getpeer_v4(tw->tw_daddr, 1);
1812 }
1813 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1814
1815 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1816 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1817 .twsk_unique = tcp_twsk_unique,
1818 .twsk_destructor= tcp_twsk_destructor,
1819 .twsk_getpeer = tcp_v4_tw_get_peer,
1820 };
1821
1822 const struct inet_connection_sock_af_ops ipv4_specific = {
1823 .queue_xmit = ip_queue_xmit,
1824 .send_check = tcp_v4_send_check,
1825 .rebuild_header = inet_sk_rebuild_header,
1826 .conn_request = tcp_v4_conn_request,
1827 .syn_recv_sock = tcp_v4_syn_recv_sock,
1828 .get_peer = tcp_v4_get_peer,
1829 .net_header_len = sizeof(struct iphdr),
1830 .setsockopt = ip_setsockopt,
1831 .getsockopt = ip_getsockopt,
1832 .addr2sockaddr = inet_csk_addr2sockaddr,
1833 .sockaddr_len = sizeof(struct sockaddr_in),
1834 .bind_conflict = inet_csk_bind_conflict,
1835 #ifdef CONFIG_COMPAT
1836 .compat_setsockopt = compat_ip_setsockopt,
1837 .compat_getsockopt = compat_ip_getsockopt,
1838 #endif
1839 };
1840 EXPORT_SYMBOL(ipv4_specific);
1841
1842 #ifdef CONFIG_TCP_MD5SIG
1843 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1844 .md5_lookup = tcp_v4_md5_lookup,
1845 .calc_md5_hash = tcp_v4_md5_hash_skb,
1846 .md5_add = tcp_v4_md5_add_func,
1847 .md5_parse = tcp_v4_parse_md5_keys,
1848 };
1849 #endif
1850
1851 /* NOTE: A lot of things set to zero explicitly by call to
1852 * sk_alloc() so need not be done here.
1853 */
1854 static int tcp_v4_init_sock(struct sock *sk)
1855 {
1856 struct inet_connection_sock *icsk = inet_csk(sk);
1857 struct tcp_sock *tp = tcp_sk(sk);
1858
1859 skb_queue_head_init(&tp->out_of_order_queue);
1860 tcp_init_xmit_timers(sk);
1861 tcp_prequeue_init(tp);
1862
1863 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1864 tp->mdev = TCP_TIMEOUT_INIT;
1865
1866 /* So many TCP implementations out there (incorrectly) count the
1867 * initial SYN frame in their delayed-ACK and congestion control
1868 * algorithms that we must have the following bandaid to talk
1869 * efficiently to them. -DaveM
1870 */
1871 tp->snd_cwnd = TCP_INIT_CWND;
1872
1873 /* See draft-stevens-tcpca-spec-01 for discussion of the
1874 * initialization of these values.
1875 */
1876 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1877 tp->snd_cwnd_clamp = ~0;
1878 tp->mss_cache = TCP_MSS_DEFAULT;
1879
1880 tp->reordering = sysctl_tcp_reordering;
1881 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1882
1883 sk->sk_state = TCP_CLOSE;
1884
1885 sk->sk_write_space = sk_stream_write_space;
1886 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1887
1888 icsk->icsk_af_ops = &ipv4_specific;
1889 icsk->icsk_sync_mss = tcp_sync_mss;
1890 #ifdef CONFIG_TCP_MD5SIG
1891 tp->af_specific = &tcp_sock_ipv4_specific;
1892 #endif
1893
1894 /* TCP Cookie Transactions */
1895 if (sysctl_tcp_cookie_size > 0) {
1896 /* Default, cookies without s_data_payload. */
1897 tp->cookie_values =
1898 kzalloc(sizeof(*tp->cookie_values),
1899 sk->sk_allocation);
1900 if (tp->cookie_values != NULL)
1901 kref_init(&tp->cookie_values->kref);
1902 }
1903 /* Presumed zeroed, in order of appearance:
1904 * cookie_in_always, cookie_out_never,
1905 * s_data_constant, s_data_in, s_data_out
1906 */
1907 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1908 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1909
1910 local_bh_disable();
1911 percpu_counter_inc(&tcp_sockets_allocated);
1912 local_bh_enable();
1913
1914 return 0;
1915 }
1916
1917 void tcp_v4_destroy_sock(struct sock *sk)
1918 {
1919 struct tcp_sock *tp = tcp_sk(sk);
1920
1921 tcp_clear_xmit_timers(sk);
1922
1923 tcp_cleanup_congestion_control(sk);
1924
1925 /* Cleanup up the write buffer. */
1926 tcp_write_queue_purge(sk);
1927
1928 /* Cleans up our, hopefully empty, out_of_order_queue. */
1929 __skb_queue_purge(&tp->out_of_order_queue);
1930
1931 #ifdef CONFIG_TCP_MD5SIG
1932 /* Clean up the MD5 key list, if any */
1933 if (tp->md5sig_info) {
1934 tcp_v4_clear_md5_list(sk);
1935 kfree(tp->md5sig_info);
1936 tp->md5sig_info = NULL;
1937 }
1938 #endif
1939
1940 #ifdef CONFIG_NET_DMA
1941 /* Cleans up our sk_async_wait_queue */
1942 __skb_queue_purge(&sk->sk_async_wait_queue);
1943 #endif
1944
1945 /* Clean prequeue, it must be empty really */
1946 __skb_queue_purge(&tp->ucopy.prequeue);
1947
1948 /* Clean up a referenced TCP bind bucket. */
1949 if (inet_csk(sk)->icsk_bind_hash)
1950 inet_put_port(sk);
1951
1952 /*
1953 * If sendmsg cached page exists, toss it.
1954 */
1955 if (sk->sk_sndmsg_page) {
1956 __free_page(sk->sk_sndmsg_page);
1957 sk->sk_sndmsg_page = NULL;
1958 }
1959
1960 /* TCP Cookie Transactions */
1961 if (tp->cookie_values != NULL) {
1962 kref_put(&tp->cookie_values->kref,
1963 tcp_cookie_values_release);
1964 tp->cookie_values = NULL;
1965 }
1966
1967 percpu_counter_dec(&tcp_sockets_allocated);
1968 }
1969 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1970
1971 #ifdef CONFIG_PROC_FS
1972 /* Proc filesystem TCP sock list dumping. */
1973
1974 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1975 {
1976 return hlist_nulls_empty(head) ? NULL :
1977 list_entry(head->first, struct inet_timewait_sock, tw_node);
1978 }
1979
1980 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1981 {
1982 return !is_a_nulls(tw->tw_node.next) ?
1983 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1984 }
1985
1986 /*
1987 * Get next listener socket follow cur. If cur is NULL, get first socket
1988 * starting from bucket given in st->bucket; when st->bucket is zero the
1989 * very first socket in the hash table is returned.
1990 */
1991 static void *listening_get_next(struct seq_file *seq, void *cur)
1992 {
1993 struct inet_connection_sock *icsk;
1994 struct hlist_nulls_node *node;
1995 struct sock *sk = cur;
1996 struct inet_listen_hashbucket *ilb;
1997 struct tcp_iter_state *st = seq->private;
1998 struct net *net = seq_file_net(seq);
1999
2000 if (!sk) {
2001 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2002 spin_lock_bh(&ilb->lock);
2003 sk = sk_nulls_head(&ilb->head);
2004 st->offset = 0;
2005 goto get_sk;
2006 }
2007 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2008 ++st->num;
2009 ++st->offset;
2010
2011 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2012 struct request_sock *req = cur;
2013
2014 icsk = inet_csk(st->syn_wait_sk);
2015 req = req->dl_next;
2016 while (1) {
2017 while (req) {
2018 if (req->rsk_ops->family == st->family) {
2019 cur = req;
2020 goto out;
2021 }
2022 req = req->dl_next;
2023 }
2024 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2025 break;
2026 get_req:
2027 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2028 }
2029 sk = sk_nulls_next(st->syn_wait_sk);
2030 st->state = TCP_SEQ_STATE_LISTENING;
2031 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2032 } else {
2033 icsk = inet_csk(sk);
2034 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2035 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2036 goto start_req;
2037 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2038 sk = sk_nulls_next(sk);
2039 }
2040 get_sk:
2041 sk_nulls_for_each_from(sk, node) {
2042 if (!net_eq(sock_net(sk), net))
2043 continue;
2044 if (sk->sk_family == st->family) {
2045 cur = sk;
2046 goto out;
2047 }
2048 icsk = inet_csk(sk);
2049 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2050 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2051 start_req:
2052 st->uid = sock_i_uid(sk);
2053 st->syn_wait_sk = sk;
2054 st->state = TCP_SEQ_STATE_OPENREQ;
2055 st->sbucket = 0;
2056 goto get_req;
2057 }
2058 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2059 }
2060 spin_unlock_bh(&ilb->lock);
2061 st->offset = 0;
2062 if (++st->bucket < INET_LHTABLE_SIZE) {
2063 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2064 spin_lock_bh(&ilb->lock);
2065 sk = sk_nulls_head(&ilb->head);
2066 goto get_sk;
2067 }
2068 cur = NULL;
2069 out:
2070 return cur;
2071 }
2072
2073 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2074 {
2075 struct tcp_iter_state *st = seq->private;
2076 void *rc;
2077
2078 st->bucket = 0;
2079 st->offset = 0;
2080 rc = listening_get_next(seq, NULL);
2081
2082 while (rc && *pos) {
2083 rc = listening_get_next(seq, rc);
2084 --*pos;
2085 }
2086 return rc;
2087 }
2088
2089 static inline int empty_bucket(struct tcp_iter_state *st)
2090 {
2091 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2092 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2093 }
2094
2095 /*
2096 * Get first established socket starting from bucket given in st->bucket.
2097 * If st->bucket is zero, the very first socket in the hash is returned.
2098 */
2099 static void *established_get_first(struct seq_file *seq)
2100 {
2101 struct tcp_iter_state *st = seq->private;
2102 struct net *net = seq_file_net(seq);
2103 void *rc = NULL;
2104
2105 st->offset = 0;
2106 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2107 struct sock *sk;
2108 struct hlist_nulls_node *node;
2109 struct inet_timewait_sock *tw;
2110 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2111
2112 /* Lockless fast path for the common case of empty buckets */
2113 if (empty_bucket(st))
2114 continue;
2115
2116 spin_lock_bh(lock);
2117 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2118 if (sk->sk_family != st->family ||
2119 !net_eq(sock_net(sk), net)) {
2120 continue;
2121 }
2122 rc = sk;
2123 goto out;
2124 }
2125 st->state = TCP_SEQ_STATE_TIME_WAIT;
2126 inet_twsk_for_each(tw, node,
2127 &tcp_hashinfo.ehash[st->bucket].twchain) {
2128 if (tw->tw_family != st->family ||
2129 !net_eq(twsk_net(tw), net)) {
2130 continue;
2131 }
2132 rc = tw;
2133 goto out;
2134 }
2135 spin_unlock_bh(lock);
2136 st->state = TCP_SEQ_STATE_ESTABLISHED;
2137 }
2138 out:
2139 return rc;
2140 }
2141
2142 static void *established_get_next(struct seq_file *seq, void *cur)
2143 {
2144 struct sock *sk = cur;
2145 struct inet_timewait_sock *tw;
2146 struct hlist_nulls_node *node;
2147 struct tcp_iter_state *st = seq->private;
2148 struct net *net = seq_file_net(seq);
2149
2150 ++st->num;
2151 ++st->offset;
2152
2153 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2154 tw = cur;
2155 tw = tw_next(tw);
2156 get_tw:
2157 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2158 tw = tw_next(tw);
2159 }
2160 if (tw) {
2161 cur = tw;
2162 goto out;
2163 }
2164 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2165 st->state = TCP_SEQ_STATE_ESTABLISHED;
2166
2167 /* Look for next non empty bucket */
2168 st->offset = 0;
2169 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2170 empty_bucket(st))
2171 ;
2172 if (st->bucket > tcp_hashinfo.ehash_mask)
2173 return NULL;
2174
2175 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2176 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2177 } else
2178 sk = sk_nulls_next(sk);
2179
2180 sk_nulls_for_each_from(sk, node) {
2181 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2182 goto found;
2183 }
2184
2185 st->state = TCP_SEQ_STATE_TIME_WAIT;
2186 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2187 goto get_tw;
2188 found:
2189 cur = sk;
2190 out:
2191 return cur;
2192 }
2193
2194 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2195 {
2196 struct tcp_iter_state *st = seq->private;
2197 void *rc;
2198
2199 st->bucket = 0;
2200 rc = established_get_first(seq);
2201
2202 while (rc && pos) {
2203 rc = established_get_next(seq, rc);
2204 --pos;
2205 }
2206 return rc;
2207 }
2208
2209 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2210 {
2211 void *rc;
2212 struct tcp_iter_state *st = seq->private;
2213
2214 st->state = TCP_SEQ_STATE_LISTENING;
2215 rc = listening_get_idx(seq, &pos);
2216
2217 if (!rc) {
2218 st->state = TCP_SEQ_STATE_ESTABLISHED;
2219 rc = established_get_idx(seq, pos);
2220 }
2221
2222 return rc;
2223 }
2224
2225 static void *tcp_seek_last_pos(struct seq_file *seq)
2226 {
2227 struct tcp_iter_state *st = seq->private;
2228 int offset = st->offset;
2229 int orig_num = st->num;
2230 void *rc = NULL;
2231
2232 switch (st->state) {
2233 case TCP_SEQ_STATE_OPENREQ:
2234 case TCP_SEQ_STATE_LISTENING:
2235 if (st->bucket >= INET_LHTABLE_SIZE)
2236 break;
2237 st->state = TCP_SEQ_STATE_LISTENING;
2238 rc = listening_get_next(seq, NULL);
2239 while (offset-- && rc)
2240 rc = listening_get_next(seq, rc);
2241 if (rc)
2242 break;
2243 st->bucket = 0;
2244 /* Fallthrough */
2245 case TCP_SEQ_STATE_ESTABLISHED:
2246 case TCP_SEQ_STATE_TIME_WAIT:
2247 st->state = TCP_SEQ_STATE_ESTABLISHED;
2248 if (st->bucket > tcp_hashinfo.ehash_mask)
2249 break;
2250 rc = established_get_first(seq);
2251 while (offset-- && rc)
2252 rc = established_get_next(seq, rc);
2253 }
2254
2255 st->num = orig_num;
2256
2257 return rc;
2258 }
2259
2260 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2261 {
2262 struct tcp_iter_state *st = seq->private;
2263 void *rc;
2264
2265 if (*pos && *pos == st->last_pos) {
2266 rc = tcp_seek_last_pos(seq);
2267 if (rc)
2268 goto out;
2269 }
2270
2271 st->state = TCP_SEQ_STATE_LISTENING;
2272 st->num = 0;
2273 st->bucket = 0;
2274 st->offset = 0;
2275 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2276
2277 out:
2278 st->last_pos = *pos;
2279 return rc;
2280 }
2281
2282 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2283 {
2284 struct tcp_iter_state *st = seq->private;
2285 void *rc = NULL;
2286
2287 if (v == SEQ_START_TOKEN) {
2288 rc = tcp_get_idx(seq, 0);
2289 goto out;
2290 }
2291
2292 switch (st->state) {
2293 case TCP_SEQ_STATE_OPENREQ:
2294 case TCP_SEQ_STATE_LISTENING:
2295 rc = listening_get_next(seq, v);
2296 if (!rc) {
2297 st->state = TCP_SEQ_STATE_ESTABLISHED;
2298 st->bucket = 0;
2299 st->offset = 0;
2300 rc = established_get_first(seq);
2301 }
2302 break;
2303 case TCP_SEQ_STATE_ESTABLISHED:
2304 case TCP_SEQ_STATE_TIME_WAIT:
2305 rc = established_get_next(seq, v);
2306 break;
2307 }
2308 out:
2309 ++*pos;
2310 st->last_pos = *pos;
2311 return rc;
2312 }
2313
2314 static void tcp_seq_stop(struct seq_file *seq, void *v)
2315 {
2316 struct tcp_iter_state *st = seq->private;
2317
2318 switch (st->state) {
2319 case TCP_SEQ_STATE_OPENREQ:
2320 if (v) {
2321 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2322 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2323 }
2324 case TCP_SEQ_STATE_LISTENING:
2325 if (v != SEQ_START_TOKEN)
2326 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2327 break;
2328 case TCP_SEQ_STATE_TIME_WAIT:
2329 case TCP_SEQ_STATE_ESTABLISHED:
2330 if (v)
2331 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2332 break;
2333 }
2334 }
2335
2336 static int tcp_seq_open(struct inode *inode, struct file *file)
2337 {
2338 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2339 struct tcp_iter_state *s;
2340 int err;
2341
2342 err = seq_open_net(inode, file, &afinfo->seq_ops,
2343 sizeof(struct tcp_iter_state));
2344 if (err < 0)
2345 return err;
2346
2347 s = ((struct seq_file *)file->private_data)->private;
2348 s->family = afinfo->family;
2349 s->last_pos = 0;
2350 return 0;
2351 }
2352
2353 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2354 {
2355 int rc = 0;
2356 struct proc_dir_entry *p;
2357
2358 afinfo->seq_fops.open = tcp_seq_open;
2359 afinfo->seq_fops.read = seq_read;
2360 afinfo->seq_fops.llseek = seq_lseek;
2361 afinfo->seq_fops.release = seq_release_net;
2362
2363 afinfo->seq_ops.start = tcp_seq_start;
2364 afinfo->seq_ops.next = tcp_seq_next;
2365 afinfo->seq_ops.stop = tcp_seq_stop;
2366
2367 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2368 &afinfo->seq_fops, afinfo);
2369 if (!p)
2370 rc = -ENOMEM;
2371 return rc;
2372 }
2373 EXPORT_SYMBOL(tcp_proc_register);
2374
2375 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2376 {
2377 proc_net_remove(net, afinfo->name);
2378 }
2379 EXPORT_SYMBOL(tcp_proc_unregister);
2380
2381 static void get_openreq4(struct sock *sk, struct request_sock *req,
2382 struct seq_file *f, int i, int uid, int *len)
2383 {
2384 const struct inet_request_sock *ireq = inet_rsk(req);
2385 int ttd = req->expires - jiffies;
2386
2387 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2388 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2389 i,
2390 ireq->loc_addr,
2391 ntohs(inet_sk(sk)->inet_sport),
2392 ireq->rmt_addr,
2393 ntohs(ireq->rmt_port),
2394 TCP_SYN_RECV,
2395 0, 0, /* could print option size, but that is af dependent. */
2396 1, /* timers active (only the expire timer) */
2397 jiffies_to_clock_t(ttd),
2398 req->retrans,
2399 uid,
2400 0, /* non standard timer */
2401 0, /* open_requests have no inode */
2402 atomic_read(&sk->sk_refcnt),
2403 req,
2404 len);
2405 }
2406
2407 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2408 {
2409 int timer_active;
2410 unsigned long timer_expires;
2411 struct tcp_sock *tp = tcp_sk(sk);
2412 const struct inet_connection_sock *icsk = inet_csk(sk);
2413 struct inet_sock *inet = inet_sk(sk);
2414 __be32 dest = inet->inet_daddr;
2415 __be32 src = inet->inet_rcv_saddr;
2416 __u16 destp = ntohs(inet->inet_dport);
2417 __u16 srcp = ntohs(inet->inet_sport);
2418 int rx_queue;
2419
2420 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2421 timer_active = 1;
2422 timer_expires = icsk->icsk_timeout;
2423 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2424 timer_active = 4;
2425 timer_expires = icsk->icsk_timeout;
2426 } else if (timer_pending(&sk->sk_timer)) {
2427 timer_active = 2;
2428 timer_expires = sk->sk_timer.expires;
2429 } else {
2430 timer_active = 0;
2431 timer_expires = jiffies;
2432 }
2433
2434 if (sk->sk_state == TCP_LISTEN)
2435 rx_queue = sk->sk_ack_backlog;
2436 else
2437 /*
2438 * because we dont lock socket, we might find a transient negative value
2439 */
2440 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2441
2442 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2443 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2444 i, src, srcp, dest, destp, sk->sk_state,
2445 tp->write_seq - tp->snd_una,
2446 rx_queue,
2447 timer_active,
2448 jiffies_to_clock_t(timer_expires - jiffies),
2449 icsk->icsk_retransmits,
2450 sock_i_uid(sk),
2451 icsk->icsk_probes_out,
2452 sock_i_ino(sk),
2453 atomic_read(&sk->sk_refcnt), sk,
2454 jiffies_to_clock_t(icsk->icsk_rto),
2455 jiffies_to_clock_t(icsk->icsk_ack.ato),
2456 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2457 tp->snd_cwnd,
2458 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2459 len);
2460 }
2461
2462 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2463 struct seq_file *f, int i, int *len)
2464 {
2465 __be32 dest, src;
2466 __u16 destp, srcp;
2467 int ttd = tw->tw_ttd - jiffies;
2468
2469 if (ttd < 0)
2470 ttd = 0;
2471
2472 dest = tw->tw_daddr;
2473 src = tw->tw_rcv_saddr;
2474 destp = ntohs(tw->tw_dport);
2475 srcp = ntohs(tw->tw_sport);
2476
2477 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2478 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2479 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2480 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2481 atomic_read(&tw->tw_refcnt), tw, len);
2482 }
2483
2484 #define TMPSZ 150
2485
2486 static int tcp4_seq_show(struct seq_file *seq, void *v)
2487 {
2488 struct tcp_iter_state *st;
2489 int len;
2490
2491 if (v == SEQ_START_TOKEN) {
2492 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2493 " sl local_address rem_address st tx_queue "
2494 "rx_queue tr tm->when retrnsmt uid timeout "
2495 "inode");
2496 goto out;
2497 }
2498 st = seq->private;
2499
2500 switch (st->state) {
2501 case TCP_SEQ_STATE_LISTENING:
2502 case TCP_SEQ_STATE_ESTABLISHED:
2503 get_tcp4_sock(v, seq, st->num, &len);
2504 break;
2505 case TCP_SEQ_STATE_OPENREQ:
2506 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2507 break;
2508 case TCP_SEQ_STATE_TIME_WAIT:
2509 get_timewait4_sock(v, seq, st->num, &len);
2510 break;
2511 }
2512 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2513 out:
2514 return 0;
2515 }
2516
2517 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2518 .name = "tcp",
2519 .family = AF_INET,
2520 .seq_fops = {
2521 .owner = THIS_MODULE,
2522 },
2523 .seq_ops = {
2524 .show = tcp4_seq_show,
2525 },
2526 };
2527
2528 static int __net_init tcp4_proc_init_net(struct net *net)
2529 {
2530 return tcp_proc_register(net, &tcp4_seq_afinfo);
2531 }
2532
2533 static void __net_exit tcp4_proc_exit_net(struct net *net)
2534 {
2535 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2536 }
2537
2538 static struct pernet_operations tcp4_net_ops = {
2539 .init = tcp4_proc_init_net,
2540 .exit = tcp4_proc_exit_net,
2541 };
2542
2543 int __init tcp4_proc_init(void)
2544 {
2545 return register_pernet_subsys(&tcp4_net_ops);
2546 }
2547
2548 void tcp4_proc_exit(void)
2549 {
2550 unregister_pernet_subsys(&tcp4_net_ops);
2551 }
2552 #endif /* CONFIG_PROC_FS */
2553
2554 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2555 {
2556 const struct iphdr *iph = skb_gro_network_header(skb);
2557
2558 switch (skb->ip_summed) {
2559 case CHECKSUM_COMPLETE:
2560 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2561 skb->csum)) {
2562 skb->ip_summed = CHECKSUM_UNNECESSARY;
2563 break;
2564 }
2565
2566 /* fall through */
2567 case CHECKSUM_NONE:
2568 NAPI_GRO_CB(skb)->flush = 1;
2569 return NULL;
2570 }
2571
2572 return tcp_gro_receive(head, skb);
2573 }
2574
2575 int tcp4_gro_complete(struct sk_buff *skb)
2576 {
2577 const struct iphdr *iph = ip_hdr(skb);
2578 struct tcphdr *th = tcp_hdr(skb);
2579
2580 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2581 iph->saddr, iph->daddr, 0);
2582 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2583
2584 return tcp_gro_complete(skb);
2585 }
2586
2587 struct proto tcp_prot = {
2588 .name = "TCP",
2589 .owner = THIS_MODULE,
2590 .close = tcp_close,
2591 .connect = tcp_v4_connect,
2592 .disconnect = tcp_disconnect,
2593 .accept = inet_csk_accept,
2594 .ioctl = tcp_ioctl,
2595 .init = tcp_v4_init_sock,
2596 .destroy = tcp_v4_destroy_sock,
2597 .shutdown = tcp_shutdown,
2598 .setsockopt = tcp_setsockopt,
2599 .getsockopt = tcp_getsockopt,
2600 .recvmsg = tcp_recvmsg,
2601 .sendmsg = tcp_sendmsg,
2602 .sendpage = tcp_sendpage,
2603 .backlog_rcv = tcp_v4_do_rcv,
2604 .hash = inet_hash,
2605 .unhash = inet_unhash,
2606 .get_port = inet_csk_get_port,
2607 .enter_memory_pressure = tcp_enter_memory_pressure,
2608 .sockets_allocated = &tcp_sockets_allocated,
2609 .orphan_count = &tcp_orphan_count,
2610 .memory_allocated = &tcp_memory_allocated,
2611 .memory_pressure = &tcp_memory_pressure,
2612 .sysctl_mem = sysctl_tcp_mem,
2613 .sysctl_wmem = sysctl_tcp_wmem,
2614 .sysctl_rmem = sysctl_tcp_rmem,
2615 .max_header = MAX_TCP_HEADER,
2616 .obj_size = sizeof(struct tcp_sock),
2617 .slab_flags = SLAB_DESTROY_BY_RCU,
2618 .twsk_prot = &tcp_timewait_sock_ops,
2619 .rsk_prot = &tcp_request_sock_ops,
2620 .h.hashinfo = &tcp_hashinfo,
2621 .no_autobind = true,
2622 #ifdef CONFIG_COMPAT
2623 .compat_setsockopt = compat_tcp_setsockopt,
2624 .compat_getsockopt = compat_tcp_getsockopt,
2625 #endif
2626 };
2627 EXPORT_SYMBOL(tcp_prot);
2628
2629
2630 static int __net_init tcp_sk_init(struct net *net)
2631 {
2632 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2633 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2634 }
2635
2636 static void __net_exit tcp_sk_exit(struct net *net)
2637 {
2638 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2639 }
2640
2641 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2642 {
2643 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2644 }
2645
2646 static struct pernet_operations __net_initdata tcp_sk_ops = {
2647 .init = tcp_sk_init,
2648 .exit = tcp_sk_exit,
2649 .exit_batch = tcp_sk_exit_batch,
2650 };
2651
2652 void __init tcp_v4_init(void)
2653 {
2654 inet_hashinfo_init(&tcp_hashinfo);
2655 if (register_pernet_subsys(&tcp_sk_ops))
2656 panic("Failed to create the TCP control socket.\n");
2657 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree