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USB: convert drivers/media/* to use module_usb_driver()
[zen-stable.git] / net / ipv4 / tcp_ipv4.c
bloba7443159c400450e73ff9b83230fe40a48d0da39
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, const 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(const 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 const 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 const 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 arg.tos = ip_hdr(skb)->tos;
656 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
657 &arg, arg.iov[0].iov_len);
658
659 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
660 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
661 }
662
663 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
664 outside socket context is ugly, certainly. What can I do?
665 */
666
667 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
668 u32 win, u32 ts, int oif,
669 struct tcp_md5sig_key *key,
670 int reply_flags, u8 tos)
671 {
672 const struct tcphdr *th = tcp_hdr(skb);
673 struct {
674 struct tcphdr th;
675 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
676 #ifdef CONFIG_TCP_MD5SIG
677 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
678 #endif
679 ];
680 } rep;
681 struct ip_reply_arg arg;
682 struct net *net = dev_net(skb_dst(skb)->dev);
683
684 memset(&rep.th, 0, sizeof(struct tcphdr));
685 memset(&arg, 0, sizeof(arg));
686
687 arg.iov[0].iov_base = (unsigned char *)&rep;
688 arg.iov[0].iov_len = sizeof(rep.th);
689 if (ts) {
690 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
691 (TCPOPT_TIMESTAMP << 8) |
692 TCPOLEN_TIMESTAMP);
693 rep.opt[1] = htonl(tcp_time_stamp);
694 rep.opt[2] = htonl(ts);
695 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
696 }
697
698 /* Swap the send and the receive. */
699 rep.th.dest = th->source;
700 rep.th.source = th->dest;
701 rep.th.doff = arg.iov[0].iov_len / 4;
702 rep.th.seq = htonl(seq);
703 rep.th.ack_seq = htonl(ack);
704 rep.th.ack = 1;
705 rep.th.window = htons(win);
706
707 #ifdef CONFIG_TCP_MD5SIG
708 if (key) {
709 int offset = (ts) ? 3 : 0;
710
711 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
712 (TCPOPT_NOP << 16) |
713 (TCPOPT_MD5SIG << 8) |
714 TCPOLEN_MD5SIG);
715 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
716 rep.th.doff = arg.iov[0].iov_len/4;
717
718 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
719 key, ip_hdr(skb)->saddr,
720 ip_hdr(skb)->daddr, &rep.th);
721 }
722 #endif
723 arg.flags = reply_flags;
724 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
725 ip_hdr(skb)->saddr, /* XXX */
726 arg.iov[0].iov_len, IPPROTO_TCP, 0);
727 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
728 if (oif)
729 arg.bound_dev_if = oif;
730 arg.tos = tos;
731 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
732 &arg, arg.iov[0].iov_len);
733
734 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
735 }
736
737 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
738 {
739 struct inet_timewait_sock *tw = inet_twsk(sk);
740 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
741
742 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
743 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
744 tcptw->tw_ts_recent,
745 tw->tw_bound_dev_if,
746 tcp_twsk_md5_key(tcptw),
747 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
748 tw->tw_tos
749 );
750
751 inet_twsk_put(tw);
752 }
753
754 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
755 struct request_sock *req)
756 {
757 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
758 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
759 req->ts_recent,
760 0,
761 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
762 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
763 ip_hdr(skb)->tos);
764 }
765
766 /*
767 * Send a SYN-ACK after having received a SYN.
768 * This still operates on a request_sock only, not on a big
769 * socket.
770 */
771 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
772 struct request_sock *req,
773 struct request_values *rvp)
774 {
775 const struct inet_request_sock *ireq = inet_rsk(req);
776 struct flowi4 fl4;
777 int err = -1;
778 struct sk_buff * skb;
779
780 /* First, grab a route. */
781 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
782 return -1;
783
784 skb = tcp_make_synack(sk, dst, req, rvp);
785
786 if (skb) {
787 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
788
789 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
790 ireq->rmt_addr,
791 ireq->opt);
792 err = net_xmit_eval(err);
793 }
794
795 dst_release(dst);
796 return err;
797 }
798
799 static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
800 struct request_values *rvp)
801 {
802 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
803 return tcp_v4_send_synack(sk, NULL, req, rvp);
804 }
805
806 /*
807 * IPv4 request_sock destructor.
808 */
809 static void tcp_v4_reqsk_destructor(struct request_sock *req)
810 {
811 kfree(inet_rsk(req)->opt);
812 }
813
814 /*
815 * Return 1 if a syncookie should be sent
816 */
817 int tcp_syn_flood_action(struct sock *sk,
818 const struct sk_buff *skb,
819 const char *proto)
820 {
821 const char *msg = "Dropping request";
822 int want_cookie = 0;
823 struct listen_sock *lopt;
824
825
826
827 #ifdef CONFIG_SYN_COOKIES
828 if (sysctl_tcp_syncookies) {
829 msg = "Sending cookies";
830 want_cookie = 1;
831 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
832 } else
833 #endif
834 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
835
836 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
837 if (!lopt->synflood_warned) {
838 lopt->synflood_warned = 1;
839 pr_info("%s: Possible SYN flooding on port %d. %s. "
840 " Check SNMP counters.\n",
841 proto, ntohs(tcp_hdr(skb)->dest), msg);
842 }
843 return want_cookie;
844 }
845 EXPORT_SYMBOL(tcp_syn_flood_action);
846
847 /*
848 * Save and compile IPv4 options into the request_sock if needed.
849 */
850 static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
851 struct sk_buff *skb)
852 {
853 const struct ip_options *opt = &(IPCB(skb)->opt);
854 struct ip_options_rcu *dopt = NULL;
855
856 if (opt && opt->optlen) {
857 int opt_size = sizeof(*dopt) + opt->optlen;
858
859 dopt = kmalloc(opt_size, GFP_ATOMIC);
860 if (dopt) {
861 if (ip_options_echo(&dopt->opt, skb)) {
862 kfree(dopt);
863 dopt = NULL;
864 }
865 }
866 }
867 return dopt;
868 }
869
870 #ifdef CONFIG_TCP_MD5SIG
871 /*
872 * RFC2385 MD5 checksumming requires a mapping of
873 * IP address->MD5 Key.
874 * We need to maintain these in the sk structure.
875 */
876
877 /* Find the Key structure for an address. */
878 static struct tcp_md5sig_key *
879 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
880 {
881 struct tcp_sock *tp = tcp_sk(sk);
882 int i;
883
884 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
885 return NULL;
886 for (i = 0; i < tp->md5sig_info->entries4; i++) {
887 if (tp->md5sig_info->keys4[i].addr == addr)
888 return &tp->md5sig_info->keys4[i].base;
889 }
890 return NULL;
891 }
892
893 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
894 struct sock *addr_sk)
895 {
896 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
897 }
898 EXPORT_SYMBOL(tcp_v4_md5_lookup);
899
900 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
901 struct request_sock *req)
902 {
903 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
904 }
905
906 /* This can be called on a newly created socket, from other files */
907 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
908 u8 *newkey, u8 newkeylen)
909 {
910 /* Add Key to the list */
911 struct tcp_md5sig_key *key;
912 struct tcp_sock *tp = tcp_sk(sk);
913 struct tcp4_md5sig_key *keys;
914
915 key = tcp_v4_md5_do_lookup(sk, addr);
916 if (key) {
917 /* Pre-existing entry - just update that one. */
918 kfree(key->key);
919 key->key = newkey;
920 key->keylen = newkeylen;
921 } else {
922 struct tcp_md5sig_info *md5sig;
923
924 if (!tp->md5sig_info) {
925 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
926 GFP_ATOMIC);
927 if (!tp->md5sig_info) {
928 kfree(newkey);
929 return -ENOMEM;
930 }
931 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
932 }
933
934 md5sig = tp->md5sig_info;
935 if (md5sig->entries4 == 0 &&
936 tcp_alloc_md5sig_pool(sk) == NULL) {
937 kfree(newkey);
938 return -ENOMEM;
939 }
940
941 if (md5sig->alloced4 == md5sig->entries4) {
942 keys = kmalloc((sizeof(*keys) *
943 (md5sig->entries4 + 1)), GFP_ATOMIC);
944 if (!keys) {
945 kfree(newkey);
946 if (md5sig->entries4 == 0)
947 tcp_free_md5sig_pool();
948 return -ENOMEM;
949 }
950
951 if (md5sig->entries4)
952 memcpy(keys, md5sig->keys4,
953 sizeof(*keys) * md5sig->entries4);
954
955 /* Free old key list, and reference new one */
956 kfree(md5sig->keys4);
957 md5sig->keys4 = keys;
958 md5sig->alloced4++;
959 }
960 md5sig->entries4++;
961 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
962 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
963 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
964 }
965 return 0;
966 }
967 EXPORT_SYMBOL(tcp_v4_md5_do_add);
968
969 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
970 u8 *newkey, u8 newkeylen)
971 {
972 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
973 newkey, newkeylen);
974 }
975
976 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
977 {
978 struct tcp_sock *tp = tcp_sk(sk);
979 int i;
980
981 for (i = 0; i < tp->md5sig_info->entries4; i++) {
982 if (tp->md5sig_info->keys4[i].addr == addr) {
983 /* Free the key */
984 kfree(tp->md5sig_info->keys4[i].base.key);
985 tp->md5sig_info->entries4--;
986
987 if (tp->md5sig_info->entries4 == 0) {
988 kfree(tp->md5sig_info->keys4);
989 tp->md5sig_info->keys4 = NULL;
990 tp->md5sig_info->alloced4 = 0;
991 tcp_free_md5sig_pool();
992 } else if (tp->md5sig_info->entries4 != i) {
993 /* Need to do some manipulation */
994 memmove(&tp->md5sig_info->keys4[i],
995 &tp->md5sig_info->keys4[i+1],
996 (tp->md5sig_info->entries4 - i) *
997 sizeof(struct tcp4_md5sig_key));
998 }
999 return 0;
1000 }
1001 }
1002 return -ENOENT;
1003 }
1004 EXPORT_SYMBOL(tcp_v4_md5_do_del);
1005
1006 static void tcp_v4_clear_md5_list(struct sock *sk)
1007 {
1008 struct tcp_sock *tp = tcp_sk(sk);
1009
1010 /* Free each key, then the set of key keys,
1011 * the crypto element, and then decrement our
1012 * hold on the last resort crypto.
1013 */
1014 if (tp->md5sig_info->entries4) {
1015 int i;
1016 for (i = 0; i < tp->md5sig_info->entries4; i++)
1017 kfree(tp->md5sig_info->keys4[i].base.key);
1018 tp->md5sig_info->entries4 = 0;
1019 tcp_free_md5sig_pool();
1020 }
1021 if (tp->md5sig_info->keys4) {
1022 kfree(tp->md5sig_info->keys4);
1023 tp->md5sig_info->keys4 = NULL;
1024 tp->md5sig_info->alloced4 = 0;
1025 }
1026 }
1027
1028 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1029 int optlen)
1030 {
1031 struct tcp_md5sig cmd;
1032 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1033 u8 *newkey;
1034
1035 if (optlen < sizeof(cmd))
1036 return -EINVAL;
1037
1038 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1039 return -EFAULT;
1040
1041 if (sin->sin_family != AF_INET)
1042 return -EINVAL;
1043
1044 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
1045 if (!tcp_sk(sk)->md5sig_info)
1046 return -ENOENT;
1047 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
1048 }
1049
1050 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1051 return -EINVAL;
1052
1053 if (!tcp_sk(sk)->md5sig_info) {
1054 struct tcp_sock *tp = tcp_sk(sk);
1055 struct tcp_md5sig_info *p;
1056
1057 p = kzalloc(sizeof(*p), sk->sk_allocation);
1058 if (!p)
1059 return -EINVAL;
1060
1061 tp->md5sig_info = p;
1062 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1063 }
1064
1065 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1066 if (!newkey)
1067 return -ENOMEM;
1068 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1069 newkey, cmd.tcpm_keylen);
1070 }
1071
1072 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1073 __be32 daddr, __be32 saddr, int nbytes)
1074 {
1075 struct tcp4_pseudohdr *bp;
1076 struct scatterlist sg;
1077
1078 bp = &hp->md5_blk.ip4;
1079
1080 /*
1081 * 1. the TCP pseudo-header (in the order: source IP address,
1082 * destination IP address, zero-padded protocol number, and
1083 * segment length)
1084 */
1085 bp->saddr = saddr;
1086 bp->daddr = daddr;
1087 bp->pad = 0;
1088 bp->protocol = IPPROTO_TCP;
1089 bp->len = cpu_to_be16(nbytes);
1090
1091 sg_init_one(&sg, bp, sizeof(*bp));
1092 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1093 }
1094
1095 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1096 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1097 {
1098 struct tcp_md5sig_pool *hp;
1099 struct hash_desc *desc;
1100
1101 hp = tcp_get_md5sig_pool();
1102 if (!hp)
1103 goto clear_hash_noput;
1104 desc = &hp->md5_desc;
1105
1106 if (crypto_hash_init(desc))
1107 goto clear_hash;
1108 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1109 goto clear_hash;
1110 if (tcp_md5_hash_header(hp, th))
1111 goto clear_hash;
1112 if (tcp_md5_hash_key(hp, key))
1113 goto clear_hash;
1114 if (crypto_hash_final(desc, md5_hash))
1115 goto clear_hash;
1116
1117 tcp_put_md5sig_pool();
1118 return 0;
1119
1120 clear_hash:
1121 tcp_put_md5sig_pool();
1122 clear_hash_noput:
1123 memset(md5_hash, 0, 16);
1124 return 1;
1125 }
1126
1127 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1128 const struct sock *sk, const struct request_sock *req,
1129 const struct sk_buff *skb)
1130 {
1131 struct tcp_md5sig_pool *hp;
1132 struct hash_desc *desc;
1133 const struct tcphdr *th = tcp_hdr(skb);
1134 __be32 saddr, daddr;
1135
1136 if (sk) {
1137 saddr = inet_sk(sk)->inet_saddr;
1138 daddr = inet_sk(sk)->inet_daddr;
1139 } else if (req) {
1140 saddr = inet_rsk(req)->loc_addr;
1141 daddr = inet_rsk(req)->rmt_addr;
1142 } else {
1143 const struct iphdr *iph = ip_hdr(skb);
1144 saddr = iph->saddr;
1145 daddr = iph->daddr;
1146 }
1147
1148 hp = tcp_get_md5sig_pool();
1149 if (!hp)
1150 goto clear_hash_noput;
1151 desc = &hp->md5_desc;
1152
1153 if (crypto_hash_init(desc))
1154 goto clear_hash;
1155
1156 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1157 goto clear_hash;
1158 if (tcp_md5_hash_header(hp, th))
1159 goto clear_hash;
1160 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1161 goto clear_hash;
1162 if (tcp_md5_hash_key(hp, key))
1163 goto clear_hash;
1164 if (crypto_hash_final(desc, md5_hash))
1165 goto clear_hash;
1166
1167 tcp_put_md5sig_pool();
1168 return 0;
1169
1170 clear_hash:
1171 tcp_put_md5sig_pool();
1172 clear_hash_noput:
1173 memset(md5_hash, 0, 16);
1174 return 1;
1175 }
1176 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1177
1178 static int tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1179 {
1180 /*
1181 * This gets called for each TCP segment that arrives
1182 * so we want to be efficient.
1183 * We have 3 drop cases:
1184 * o No MD5 hash and one expected.
1185 * o MD5 hash and we're not expecting one.
1186 * o MD5 hash and its wrong.
1187 */
1188 const __u8 *hash_location = NULL;
1189 struct tcp_md5sig_key *hash_expected;
1190 const struct iphdr *iph = ip_hdr(skb);
1191 const struct tcphdr *th = tcp_hdr(skb);
1192 int genhash;
1193 unsigned char newhash[16];
1194
1195 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1196 hash_location = tcp_parse_md5sig_option(th);
1197
1198 /* We've parsed the options - do we have a hash? */
1199 if (!hash_expected && !hash_location)
1200 return 0;
1201
1202 if (hash_expected && !hash_location) {
1203 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1204 return 1;
1205 }
1206
1207 if (!hash_expected && hash_location) {
1208 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1209 return 1;
1210 }
1211
1212 /* Okay, so this is hash_expected and hash_location -
1213 * so we need to calculate the checksum.
1214 */
1215 genhash = tcp_v4_md5_hash_skb(newhash,
1216 hash_expected,
1217 NULL, NULL, skb);
1218
1219 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1220 if (net_ratelimit()) {
1221 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1222 &iph->saddr, ntohs(th->source),
1223 &iph->daddr, ntohs(th->dest),
1224 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1225 }
1226 return 1;
1227 }
1228 return 0;
1229 }
1230
1231 #endif
1232
1233 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1234 .family = PF_INET,
1235 .obj_size = sizeof(struct tcp_request_sock),
1236 .rtx_syn_ack = tcp_v4_rtx_synack,
1237 .send_ack = tcp_v4_reqsk_send_ack,
1238 .destructor = tcp_v4_reqsk_destructor,
1239 .send_reset = tcp_v4_send_reset,
1240 .syn_ack_timeout = tcp_syn_ack_timeout,
1241 };
1242
1243 #ifdef CONFIG_TCP_MD5SIG
1244 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1245 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1246 .calc_md5_hash = tcp_v4_md5_hash_skb,
1247 };
1248 #endif
1249
1250 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1251 {
1252 struct tcp_extend_values tmp_ext;
1253 struct tcp_options_received tmp_opt;
1254 const u8 *hash_location;
1255 struct request_sock *req;
1256 struct inet_request_sock *ireq;
1257 struct tcp_sock *tp = tcp_sk(sk);
1258 struct dst_entry *dst = NULL;
1259 __be32 saddr = ip_hdr(skb)->saddr;
1260 __be32 daddr = ip_hdr(skb)->daddr;
1261 __u32 isn = TCP_SKB_CB(skb)->when;
1262 int want_cookie = 0;
1263
1264 /* Never answer to SYNs send to broadcast or multicast */
1265 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1266 goto drop;
1267
1268 /* TW buckets are converted to open requests without
1269 * limitations, they conserve resources and peer is
1270 * evidently real one.
1271 */
1272 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1273 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1274 if (!want_cookie)
1275 goto drop;
1276 }
1277
1278 /* Accept backlog is full. If we have already queued enough
1279 * of warm entries in syn queue, drop request. It is better than
1280 * clogging syn queue with openreqs with exponentially increasing
1281 * timeout.
1282 */
1283 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1284 goto drop;
1285
1286 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1287 if (!req)
1288 goto drop;
1289
1290 #ifdef CONFIG_TCP_MD5SIG
1291 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1292 #endif
1293
1294 tcp_clear_options(&tmp_opt);
1295 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1296 tmp_opt.user_mss = tp->rx_opt.user_mss;
1297 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1298
1299 if (tmp_opt.cookie_plus > 0 &&
1300 tmp_opt.saw_tstamp &&
1301 !tp->rx_opt.cookie_out_never &&
1302 (sysctl_tcp_cookie_size > 0 ||
1303 (tp->cookie_values != NULL &&
1304 tp->cookie_values->cookie_desired > 0))) {
1305 u8 *c;
1306 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1307 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1308
1309 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1310 goto drop_and_release;
1311
1312 /* Secret recipe starts with IP addresses */
1313 *mess++ ^= (__force u32)daddr;
1314 *mess++ ^= (__force u32)saddr;
1315
1316 /* plus variable length Initiator Cookie */
1317 c = (u8 *)mess;
1318 while (l-- > 0)
1319 *c++ ^= *hash_location++;
1320
1321 want_cookie = 0; /* not our kind of cookie */
1322 tmp_ext.cookie_out_never = 0; /* false */
1323 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1324 } else if (!tp->rx_opt.cookie_in_always) {
1325 /* redundant indications, but ensure initialization. */
1326 tmp_ext.cookie_out_never = 1; /* true */
1327 tmp_ext.cookie_plus = 0;
1328 } else {
1329 goto drop_and_release;
1330 }
1331 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1332
1333 if (want_cookie && !tmp_opt.saw_tstamp)
1334 tcp_clear_options(&tmp_opt);
1335
1336 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1337 tcp_openreq_init(req, &tmp_opt, skb);
1338
1339 ireq = inet_rsk(req);
1340 ireq->loc_addr = daddr;
1341 ireq->rmt_addr = saddr;
1342 ireq->no_srccheck = inet_sk(sk)->transparent;
1343 ireq->opt = tcp_v4_save_options(sk, skb);
1344
1345 if (security_inet_conn_request(sk, skb, req))
1346 goto drop_and_free;
1347
1348 if (!want_cookie || tmp_opt.tstamp_ok)
1349 TCP_ECN_create_request(req, tcp_hdr(skb));
1350
1351 if (want_cookie) {
1352 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1353 req->cookie_ts = tmp_opt.tstamp_ok;
1354 } else if (!isn) {
1355 struct inet_peer *peer = NULL;
1356 struct flowi4 fl4;
1357
1358 /* VJ's idea. We save last timestamp seen
1359 * from the destination in peer table, when entering
1360 * state TIME-WAIT, and check against it before
1361 * accepting new connection request.
1362 *
1363 * If "isn" is not zero, this request hit alive
1364 * timewait bucket, so that all the necessary checks
1365 * are made in the function processing timewait state.
1366 */
1367 if (tmp_opt.saw_tstamp &&
1368 tcp_death_row.sysctl_tw_recycle &&
1369 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1370 fl4.daddr == saddr &&
1371 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1372 inet_peer_refcheck(peer);
1373 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1374 (s32)(peer->tcp_ts - req->ts_recent) >
1375 TCP_PAWS_WINDOW) {
1376 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1377 goto drop_and_release;
1378 }
1379 }
1380 /* Kill the following clause, if you dislike this way. */
1381 else if (!sysctl_tcp_syncookies &&
1382 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1383 (sysctl_max_syn_backlog >> 2)) &&
1384 (!peer || !peer->tcp_ts_stamp) &&
1385 (!dst || !dst_metric(dst, RTAX_RTT))) {
1386 /* Without syncookies last quarter of
1387 * backlog is filled with destinations,
1388 * proven to be alive.
1389 * It means that we continue to communicate
1390 * to destinations, already remembered
1391 * to the moment of synflood.
1392 */
1393 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1394 &saddr, ntohs(tcp_hdr(skb)->source));
1395 goto drop_and_release;
1396 }
1397
1398 isn = tcp_v4_init_sequence(skb);
1399 }
1400 tcp_rsk(req)->snt_isn = isn;
1401 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1402
1403 if (tcp_v4_send_synack(sk, dst, req,
1404 (struct request_values *)&tmp_ext) ||
1405 want_cookie)
1406 goto drop_and_free;
1407
1408 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1409 return 0;
1410
1411 drop_and_release:
1412 dst_release(dst);
1413 drop_and_free:
1414 reqsk_free(req);
1415 drop:
1416 return 0;
1417 }
1418 EXPORT_SYMBOL(tcp_v4_conn_request);
1419
1420
1421 /*
1422 * The three way handshake has completed - we got a valid synack -
1423 * now create the new socket.
1424 */
1425 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1426 struct request_sock *req,
1427 struct dst_entry *dst)
1428 {
1429 struct inet_request_sock *ireq;
1430 struct inet_sock *newinet;
1431 struct tcp_sock *newtp;
1432 struct sock *newsk;
1433 #ifdef CONFIG_TCP_MD5SIG
1434 struct tcp_md5sig_key *key;
1435 #endif
1436 struct ip_options_rcu *inet_opt;
1437
1438 if (sk_acceptq_is_full(sk))
1439 goto exit_overflow;
1440
1441 newsk = tcp_create_openreq_child(sk, req, skb);
1442 if (!newsk)
1443 goto exit_nonewsk;
1444
1445 newsk->sk_gso_type = SKB_GSO_TCPV4;
1446
1447 newtp = tcp_sk(newsk);
1448 newinet = inet_sk(newsk);
1449 ireq = inet_rsk(req);
1450 newinet->inet_daddr = ireq->rmt_addr;
1451 newinet->inet_rcv_saddr = ireq->loc_addr;
1452 newinet->inet_saddr = ireq->loc_addr;
1453 inet_opt = ireq->opt;
1454 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1455 ireq->opt = NULL;
1456 newinet->mc_index = inet_iif(skb);
1457 newinet->mc_ttl = ip_hdr(skb)->ttl;
1458 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1459 if (inet_opt)
1460 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1461 newinet->inet_id = newtp->write_seq ^ jiffies;
1462
1463 if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
1464 goto put_and_exit;
1465
1466 sk_setup_caps(newsk, dst);
1467
1468 tcp_mtup_init(newsk);
1469 tcp_sync_mss(newsk, dst_mtu(dst));
1470 newtp->advmss = dst_metric_advmss(dst);
1471 if (tcp_sk(sk)->rx_opt.user_mss &&
1472 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1473 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1474
1475 tcp_initialize_rcv_mss(newsk);
1476 if (tcp_rsk(req)->snt_synack)
1477 tcp_valid_rtt_meas(newsk,
1478 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1479 newtp->total_retrans = req->retrans;
1480
1481 #ifdef CONFIG_TCP_MD5SIG
1482 /* Copy over the MD5 key from the original socket */
1483 key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
1484 if (key != NULL) {
1485 /*
1486 * We're using one, so create a matching key
1487 * on the newsk structure. If we fail to get
1488 * memory, then we end up not copying the key
1489 * across. Shucks.
1490 */
1491 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1492 if (newkey != NULL)
1493 tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1494 newkey, key->keylen);
1495 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1496 }
1497 #endif
1498
1499 if (__inet_inherit_port(sk, newsk) < 0)
1500 goto put_and_exit;
1501 __inet_hash_nolisten(newsk, NULL);
1502
1503 return newsk;
1504
1505 exit_overflow:
1506 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1507 exit_nonewsk:
1508 dst_release(dst);
1509 exit:
1510 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1511 return NULL;
1512 put_and_exit:
1513 bh_unlock_sock(newsk);
1514 sock_put(newsk);
1515 goto exit;
1516 }
1517 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1518
1519 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1520 {
1521 struct tcphdr *th = tcp_hdr(skb);
1522 const struct iphdr *iph = ip_hdr(skb);
1523 struct sock *nsk;
1524 struct request_sock **prev;
1525 /* Find possible connection requests. */
1526 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1527 iph->saddr, iph->daddr);
1528 if (req)
1529 return tcp_check_req(sk, skb, req, prev);
1530
1531 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1532 th->source, iph->daddr, th->dest, inet_iif(skb));
1533
1534 if (nsk) {
1535 if (nsk->sk_state != TCP_TIME_WAIT) {
1536 bh_lock_sock(nsk);
1537 return nsk;
1538 }
1539 inet_twsk_put(inet_twsk(nsk));
1540 return NULL;
1541 }
1542
1543 #ifdef CONFIG_SYN_COOKIES
1544 if (!th->syn)
1545 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1546 #endif
1547 return sk;
1548 }
1549
1550 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1551 {
1552 const struct iphdr *iph = ip_hdr(skb);
1553
1554 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1555 if (!tcp_v4_check(skb->len, iph->saddr,
1556 iph->daddr, skb->csum)) {
1557 skb->ip_summed = CHECKSUM_UNNECESSARY;
1558 return 0;
1559 }
1560 }
1561
1562 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1563 skb->len, IPPROTO_TCP, 0);
1564
1565 if (skb->len <= 76) {
1566 return __skb_checksum_complete(skb);
1567 }
1568 return 0;
1569 }
1570
1571
1572 /* The socket must have it's spinlock held when we get
1573 * here.
1574 *
1575 * We have a potential double-lock case here, so even when
1576 * doing backlog processing we use the BH locking scheme.
1577 * This is because we cannot sleep with the original spinlock
1578 * held.
1579 */
1580 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1581 {
1582 struct sock *rsk;
1583 #ifdef CONFIG_TCP_MD5SIG
1584 /*
1585 * We really want to reject the packet as early as possible
1586 * if:
1587 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1588 * o There is an MD5 option and we're not expecting one
1589 */
1590 if (tcp_v4_inbound_md5_hash(sk, skb))
1591 goto discard;
1592 #endif
1593
1594 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1595 sock_rps_save_rxhash(sk, skb);
1596 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1597 rsk = sk;
1598 goto reset;
1599 }
1600 return 0;
1601 }
1602
1603 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1604 goto csum_err;
1605
1606 if (sk->sk_state == TCP_LISTEN) {
1607 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1608 if (!nsk)
1609 goto discard;
1610
1611 if (nsk != sk) {
1612 sock_rps_save_rxhash(nsk, skb);
1613 if (tcp_child_process(sk, nsk, skb)) {
1614 rsk = nsk;
1615 goto reset;
1616 }
1617 return 0;
1618 }
1619 } else
1620 sock_rps_save_rxhash(sk, skb);
1621
1622 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1623 rsk = sk;
1624 goto reset;
1625 }
1626 return 0;
1627
1628 reset:
1629 tcp_v4_send_reset(rsk, skb);
1630 discard:
1631 kfree_skb(skb);
1632 /* Be careful here. If this function gets more complicated and
1633 * gcc suffers from register pressure on the x86, sk (in %ebx)
1634 * might be destroyed here. This current version compiles correctly,
1635 * but you have been warned.
1636 */
1637 return 0;
1638
1639 csum_err:
1640 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1641 goto discard;
1642 }
1643 EXPORT_SYMBOL(tcp_v4_do_rcv);
1644
1645 /*
1646 * From tcp_input.c
1647 */
1648
1649 int tcp_v4_rcv(struct sk_buff *skb)
1650 {
1651 const struct iphdr *iph;
1652 const struct tcphdr *th;
1653 struct sock *sk;
1654 int ret;
1655 struct net *net = dev_net(skb->dev);
1656
1657 if (skb->pkt_type != PACKET_HOST)
1658 goto discard_it;
1659
1660 /* Count it even if it's bad */
1661 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1662
1663 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1664 goto discard_it;
1665
1666 th = tcp_hdr(skb);
1667
1668 if (th->doff < sizeof(struct tcphdr) / 4)
1669 goto bad_packet;
1670 if (!pskb_may_pull(skb, th->doff * 4))
1671 goto discard_it;
1672
1673 /* An explanation is required here, I think.
1674 * Packet length and doff are validated by header prediction,
1675 * provided case of th->doff==0 is eliminated.
1676 * So, we defer the checks. */
1677 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1678 goto bad_packet;
1679
1680 th = tcp_hdr(skb);
1681 iph = ip_hdr(skb);
1682 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1683 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1684 skb->len - th->doff * 4);
1685 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1686 TCP_SKB_CB(skb)->when = 0;
1687 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1688 TCP_SKB_CB(skb)->sacked = 0;
1689
1690 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1691 if (!sk)
1692 goto no_tcp_socket;
1693
1694 process:
1695 if (sk->sk_state == TCP_TIME_WAIT)
1696 goto do_time_wait;
1697
1698 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1699 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1700 goto discard_and_relse;
1701 }
1702
1703 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1704 goto discard_and_relse;
1705 nf_reset(skb);
1706
1707 if (sk_filter(sk, skb))
1708 goto discard_and_relse;
1709
1710 skb->dev = NULL;
1711
1712 bh_lock_sock_nested(sk);
1713 ret = 0;
1714 if (!sock_owned_by_user(sk)) {
1715 #ifdef CONFIG_NET_DMA
1716 struct tcp_sock *tp = tcp_sk(sk);
1717 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1718 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1719 if (tp->ucopy.dma_chan)
1720 ret = tcp_v4_do_rcv(sk, skb);
1721 else
1722 #endif
1723 {
1724 if (!tcp_prequeue(sk, skb))
1725 ret = tcp_v4_do_rcv(sk, skb);
1726 }
1727 } else if (unlikely(sk_add_backlog(sk, skb))) {
1728 bh_unlock_sock(sk);
1729 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1730 goto discard_and_relse;
1731 }
1732 bh_unlock_sock(sk);
1733
1734 sock_put(sk);
1735
1736 return ret;
1737
1738 no_tcp_socket:
1739 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1740 goto discard_it;
1741
1742 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1743 bad_packet:
1744 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1745 } else {
1746 tcp_v4_send_reset(NULL, skb);
1747 }
1748
1749 discard_it:
1750 /* Discard frame. */
1751 kfree_skb(skb);
1752 return 0;
1753
1754 discard_and_relse:
1755 sock_put(sk);
1756 goto discard_it;
1757
1758 do_time_wait:
1759 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1760 inet_twsk_put(inet_twsk(sk));
1761 goto discard_it;
1762 }
1763
1764 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1765 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1766 inet_twsk_put(inet_twsk(sk));
1767 goto discard_it;
1768 }
1769 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1770 case TCP_TW_SYN: {
1771 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1772 &tcp_hashinfo,
1773 iph->daddr, th->dest,
1774 inet_iif(skb));
1775 if (sk2) {
1776 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1777 inet_twsk_put(inet_twsk(sk));
1778 sk = sk2;
1779 goto process;
1780 }
1781 /* Fall through to ACK */
1782 }
1783 case TCP_TW_ACK:
1784 tcp_v4_timewait_ack(sk, skb);
1785 break;
1786 case TCP_TW_RST:
1787 goto no_tcp_socket;
1788 case TCP_TW_SUCCESS:;
1789 }
1790 goto discard_it;
1791 }
1792
1793 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1794 {
1795 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1796 struct inet_sock *inet = inet_sk(sk);
1797 struct inet_peer *peer;
1798
1799 if (!rt ||
1800 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1801 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1802 *release_it = true;
1803 } else {
1804 if (!rt->peer)
1805 rt_bind_peer(rt, inet->inet_daddr, 1);
1806 peer = rt->peer;
1807 *release_it = false;
1808 }
1809
1810 return peer;
1811 }
1812 EXPORT_SYMBOL(tcp_v4_get_peer);
1813
1814 void *tcp_v4_tw_get_peer(struct sock *sk)
1815 {
1816 const struct inet_timewait_sock *tw = inet_twsk(sk);
1817
1818 return inet_getpeer_v4(tw->tw_daddr, 1);
1819 }
1820 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1821
1822 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1823 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1824 .twsk_unique = tcp_twsk_unique,
1825 .twsk_destructor= tcp_twsk_destructor,
1826 .twsk_getpeer = tcp_v4_tw_get_peer,
1827 };
1828
1829 const struct inet_connection_sock_af_ops ipv4_specific = {
1830 .queue_xmit = ip_queue_xmit,
1831 .send_check = tcp_v4_send_check,
1832 .rebuild_header = inet_sk_rebuild_header,
1833 .conn_request = tcp_v4_conn_request,
1834 .syn_recv_sock = tcp_v4_syn_recv_sock,
1835 .get_peer = tcp_v4_get_peer,
1836 .net_header_len = sizeof(struct iphdr),
1837 .setsockopt = ip_setsockopt,
1838 .getsockopt = ip_getsockopt,
1839 .addr2sockaddr = inet_csk_addr2sockaddr,
1840 .sockaddr_len = sizeof(struct sockaddr_in),
1841 .bind_conflict = inet_csk_bind_conflict,
1842 #ifdef CONFIG_COMPAT
1843 .compat_setsockopt = compat_ip_setsockopt,
1844 .compat_getsockopt = compat_ip_getsockopt,
1845 #endif
1846 };
1847 EXPORT_SYMBOL(ipv4_specific);
1848
1849 #ifdef CONFIG_TCP_MD5SIG
1850 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1851 .md5_lookup = tcp_v4_md5_lookup,
1852 .calc_md5_hash = tcp_v4_md5_hash_skb,
1853 .md5_add = tcp_v4_md5_add_func,
1854 .md5_parse = tcp_v4_parse_md5_keys,
1855 };
1856 #endif
1857
1858 /* NOTE: A lot of things set to zero explicitly by call to
1859 * sk_alloc() so need not be done here.
1860 */
1861 static int tcp_v4_init_sock(struct sock *sk)
1862 {
1863 struct inet_connection_sock *icsk = inet_csk(sk);
1864 struct tcp_sock *tp = tcp_sk(sk);
1865
1866 skb_queue_head_init(&tp->out_of_order_queue);
1867 tcp_init_xmit_timers(sk);
1868 tcp_prequeue_init(tp);
1869
1870 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1871 tp->mdev = TCP_TIMEOUT_INIT;
1872
1873 /* So many TCP implementations out there (incorrectly) count the
1874 * initial SYN frame in their delayed-ACK and congestion control
1875 * algorithms that we must have the following bandaid to talk
1876 * efficiently to them. -DaveM
1877 */
1878 tp->snd_cwnd = TCP_INIT_CWND;
1879
1880 /* See draft-stevens-tcpca-spec-01 for discussion of the
1881 * initialization of these values.
1882 */
1883 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1884 tp->snd_cwnd_clamp = ~0;
1885 tp->mss_cache = TCP_MSS_DEFAULT;
1886
1887 tp->reordering = sysctl_tcp_reordering;
1888 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1889
1890 sk->sk_state = TCP_CLOSE;
1891
1892 sk->sk_write_space = sk_stream_write_space;
1893 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1894
1895 icsk->icsk_af_ops = &ipv4_specific;
1896 icsk->icsk_sync_mss = tcp_sync_mss;
1897 #ifdef CONFIG_TCP_MD5SIG
1898 tp->af_specific = &tcp_sock_ipv4_specific;
1899 #endif
1900
1901 /* TCP Cookie Transactions */
1902 if (sysctl_tcp_cookie_size > 0) {
1903 /* Default, cookies without s_data_payload. */
1904 tp->cookie_values =
1905 kzalloc(sizeof(*tp->cookie_values),
1906 sk->sk_allocation);
1907 if (tp->cookie_values != NULL)
1908 kref_init(&tp->cookie_values->kref);
1909 }
1910 /* Presumed zeroed, in order of appearance:
1911 * cookie_in_always, cookie_out_never,
1912 * s_data_constant, s_data_in, s_data_out
1913 */
1914 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1915 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1916
1917 local_bh_disable();
1918 percpu_counter_inc(&tcp_sockets_allocated);
1919 local_bh_enable();
1920
1921 return 0;
1922 }
1923
1924 void tcp_v4_destroy_sock(struct sock *sk)
1925 {
1926 struct tcp_sock *tp = tcp_sk(sk);
1927
1928 tcp_clear_xmit_timers(sk);
1929
1930 tcp_cleanup_congestion_control(sk);
1931
1932 /* Cleanup up the write buffer. */
1933 tcp_write_queue_purge(sk);
1934
1935 /* Cleans up our, hopefully empty, out_of_order_queue. */
1936 __skb_queue_purge(&tp->out_of_order_queue);
1937
1938 #ifdef CONFIG_TCP_MD5SIG
1939 /* Clean up the MD5 key list, if any */
1940 if (tp->md5sig_info) {
1941 tcp_v4_clear_md5_list(sk);
1942 kfree(tp->md5sig_info);
1943 tp->md5sig_info = NULL;
1944 }
1945 #endif
1946
1947 #ifdef CONFIG_NET_DMA
1948 /* Cleans up our sk_async_wait_queue */
1949 __skb_queue_purge(&sk->sk_async_wait_queue);
1950 #endif
1951
1952 /* Clean prequeue, it must be empty really */
1953 __skb_queue_purge(&tp->ucopy.prequeue);
1954
1955 /* Clean up a referenced TCP bind bucket. */
1956 if (inet_csk(sk)->icsk_bind_hash)
1957 inet_put_port(sk);
1958
1959 /*
1960 * If sendmsg cached page exists, toss it.
1961 */
1962 if (sk->sk_sndmsg_page) {
1963 __free_page(sk->sk_sndmsg_page);
1964 sk->sk_sndmsg_page = NULL;
1965 }
1966
1967 /* TCP Cookie Transactions */
1968 if (tp->cookie_values != NULL) {
1969 kref_put(&tp->cookie_values->kref,
1970 tcp_cookie_values_release);
1971 tp->cookie_values = NULL;
1972 }
1973
1974 percpu_counter_dec(&tcp_sockets_allocated);
1975 }
1976 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1977
1978 #ifdef CONFIG_PROC_FS
1979 /* Proc filesystem TCP sock list dumping. */
1980
1981 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1982 {
1983 return hlist_nulls_empty(head) ? NULL :
1984 list_entry(head->first, struct inet_timewait_sock, tw_node);
1985 }
1986
1987 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1988 {
1989 return !is_a_nulls(tw->tw_node.next) ?
1990 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1991 }
1992
1993 /*
1994 * Get next listener socket follow cur. If cur is NULL, get first socket
1995 * starting from bucket given in st->bucket; when st->bucket is zero the
1996 * very first socket in the hash table is returned.
1997 */
1998 static void *listening_get_next(struct seq_file *seq, void *cur)
1999 {
2000 struct inet_connection_sock *icsk;
2001 struct hlist_nulls_node *node;
2002 struct sock *sk = cur;
2003 struct inet_listen_hashbucket *ilb;
2004 struct tcp_iter_state *st = seq->private;
2005 struct net *net = seq_file_net(seq);
2006
2007 if (!sk) {
2008 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2009 spin_lock_bh(&ilb->lock);
2010 sk = sk_nulls_head(&ilb->head);
2011 st->offset = 0;
2012 goto get_sk;
2013 }
2014 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2015 ++st->num;
2016 ++st->offset;
2017
2018 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2019 struct request_sock *req = cur;
2020
2021 icsk = inet_csk(st->syn_wait_sk);
2022 req = req->dl_next;
2023 while (1) {
2024 while (req) {
2025 if (req->rsk_ops->family == st->family) {
2026 cur = req;
2027 goto out;
2028 }
2029 req = req->dl_next;
2030 }
2031 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2032 break;
2033 get_req:
2034 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2035 }
2036 sk = sk_nulls_next(st->syn_wait_sk);
2037 st->state = TCP_SEQ_STATE_LISTENING;
2038 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2039 } else {
2040 icsk = inet_csk(sk);
2041 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2042 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2043 goto start_req;
2044 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2045 sk = sk_nulls_next(sk);
2046 }
2047 get_sk:
2048 sk_nulls_for_each_from(sk, node) {
2049 if (!net_eq(sock_net(sk), net))
2050 continue;
2051 if (sk->sk_family == st->family) {
2052 cur = sk;
2053 goto out;
2054 }
2055 icsk = inet_csk(sk);
2056 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2057 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2058 start_req:
2059 st->uid = sock_i_uid(sk);
2060 st->syn_wait_sk = sk;
2061 st->state = TCP_SEQ_STATE_OPENREQ;
2062 st->sbucket = 0;
2063 goto get_req;
2064 }
2065 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2066 }
2067 spin_unlock_bh(&ilb->lock);
2068 st->offset = 0;
2069 if (++st->bucket < INET_LHTABLE_SIZE) {
2070 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2071 spin_lock_bh(&ilb->lock);
2072 sk = sk_nulls_head(&ilb->head);
2073 goto get_sk;
2074 }
2075 cur = NULL;
2076 out:
2077 return cur;
2078 }
2079
2080 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2081 {
2082 struct tcp_iter_state *st = seq->private;
2083 void *rc;
2084
2085 st->bucket = 0;
2086 st->offset = 0;
2087 rc = listening_get_next(seq, NULL);
2088
2089 while (rc && *pos) {
2090 rc = listening_get_next(seq, rc);
2091 --*pos;
2092 }
2093 return rc;
2094 }
2095
2096 static inline int empty_bucket(struct tcp_iter_state *st)
2097 {
2098 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2099 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2100 }
2101
2102 /*
2103 * Get first established socket starting from bucket given in st->bucket.
2104 * If st->bucket is zero, the very first socket in the hash is returned.
2105 */
2106 static void *established_get_first(struct seq_file *seq)
2107 {
2108 struct tcp_iter_state *st = seq->private;
2109 struct net *net = seq_file_net(seq);
2110 void *rc = NULL;
2111
2112 st->offset = 0;
2113 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2114 struct sock *sk;
2115 struct hlist_nulls_node *node;
2116 struct inet_timewait_sock *tw;
2117 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2118
2119 /* Lockless fast path for the common case of empty buckets */
2120 if (empty_bucket(st))
2121 continue;
2122
2123 spin_lock_bh(lock);
2124 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2125 if (sk->sk_family != st->family ||
2126 !net_eq(sock_net(sk), net)) {
2127 continue;
2128 }
2129 rc = sk;
2130 goto out;
2131 }
2132 st->state = TCP_SEQ_STATE_TIME_WAIT;
2133 inet_twsk_for_each(tw, node,
2134 &tcp_hashinfo.ehash[st->bucket].twchain) {
2135 if (tw->tw_family != st->family ||
2136 !net_eq(twsk_net(tw), net)) {
2137 continue;
2138 }
2139 rc = tw;
2140 goto out;
2141 }
2142 spin_unlock_bh(lock);
2143 st->state = TCP_SEQ_STATE_ESTABLISHED;
2144 }
2145 out:
2146 return rc;
2147 }
2148
2149 static void *established_get_next(struct seq_file *seq, void *cur)
2150 {
2151 struct sock *sk = cur;
2152 struct inet_timewait_sock *tw;
2153 struct hlist_nulls_node *node;
2154 struct tcp_iter_state *st = seq->private;
2155 struct net *net = seq_file_net(seq);
2156
2157 ++st->num;
2158 ++st->offset;
2159
2160 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2161 tw = cur;
2162 tw = tw_next(tw);
2163 get_tw:
2164 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2165 tw = tw_next(tw);
2166 }
2167 if (tw) {
2168 cur = tw;
2169 goto out;
2170 }
2171 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2172 st->state = TCP_SEQ_STATE_ESTABLISHED;
2173
2174 /* Look for next non empty bucket */
2175 st->offset = 0;
2176 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2177 empty_bucket(st))
2178 ;
2179 if (st->bucket > tcp_hashinfo.ehash_mask)
2180 return NULL;
2181
2182 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2183 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2184 } else
2185 sk = sk_nulls_next(sk);
2186
2187 sk_nulls_for_each_from(sk, node) {
2188 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2189 goto found;
2190 }
2191
2192 st->state = TCP_SEQ_STATE_TIME_WAIT;
2193 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2194 goto get_tw;
2195 found:
2196 cur = sk;
2197 out:
2198 return cur;
2199 }
2200
2201 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2202 {
2203 struct tcp_iter_state *st = seq->private;
2204 void *rc;
2205
2206 st->bucket = 0;
2207 rc = established_get_first(seq);
2208
2209 while (rc && pos) {
2210 rc = established_get_next(seq, rc);
2211 --pos;
2212 }
2213 return rc;
2214 }
2215
2216 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2217 {
2218 void *rc;
2219 struct tcp_iter_state *st = seq->private;
2220
2221 st->state = TCP_SEQ_STATE_LISTENING;
2222 rc = listening_get_idx(seq, &pos);
2223
2224 if (!rc) {
2225 st->state = TCP_SEQ_STATE_ESTABLISHED;
2226 rc = established_get_idx(seq, pos);
2227 }
2228
2229 return rc;
2230 }
2231
2232 static void *tcp_seek_last_pos(struct seq_file *seq)
2233 {
2234 struct tcp_iter_state *st = seq->private;
2235 int offset = st->offset;
2236 int orig_num = st->num;
2237 void *rc = NULL;
2238
2239 switch (st->state) {
2240 case TCP_SEQ_STATE_OPENREQ:
2241 case TCP_SEQ_STATE_LISTENING:
2242 if (st->bucket >= INET_LHTABLE_SIZE)
2243 break;
2244 st->state = TCP_SEQ_STATE_LISTENING;
2245 rc = listening_get_next(seq, NULL);
2246 while (offset-- && rc)
2247 rc = listening_get_next(seq, rc);
2248 if (rc)
2249 break;
2250 st->bucket = 0;
2251 /* Fallthrough */
2252 case TCP_SEQ_STATE_ESTABLISHED:
2253 case TCP_SEQ_STATE_TIME_WAIT:
2254 st->state = TCP_SEQ_STATE_ESTABLISHED;
2255 if (st->bucket > tcp_hashinfo.ehash_mask)
2256 break;
2257 rc = established_get_first(seq);
2258 while (offset-- && rc)
2259 rc = established_get_next(seq, rc);
2260 }
2261
2262 st->num = orig_num;
2263
2264 return rc;
2265 }
2266
2267 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2268 {
2269 struct tcp_iter_state *st = seq->private;
2270 void *rc;
2271
2272 if (*pos && *pos == st->last_pos) {
2273 rc = tcp_seek_last_pos(seq);
2274 if (rc)
2275 goto out;
2276 }
2277
2278 st->state = TCP_SEQ_STATE_LISTENING;
2279 st->num = 0;
2280 st->bucket = 0;
2281 st->offset = 0;
2282 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2283
2284 out:
2285 st->last_pos = *pos;
2286 return rc;
2287 }
2288
2289 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2290 {
2291 struct tcp_iter_state *st = seq->private;
2292 void *rc = NULL;
2293
2294 if (v == SEQ_START_TOKEN) {
2295 rc = tcp_get_idx(seq, 0);
2296 goto out;
2297 }
2298
2299 switch (st->state) {
2300 case TCP_SEQ_STATE_OPENREQ:
2301 case TCP_SEQ_STATE_LISTENING:
2302 rc = listening_get_next(seq, v);
2303 if (!rc) {
2304 st->state = TCP_SEQ_STATE_ESTABLISHED;
2305 st->bucket = 0;
2306 st->offset = 0;
2307 rc = established_get_first(seq);
2308 }
2309 break;
2310 case TCP_SEQ_STATE_ESTABLISHED:
2311 case TCP_SEQ_STATE_TIME_WAIT:
2312 rc = established_get_next(seq, v);
2313 break;
2314 }
2315 out:
2316 ++*pos;
2317 st->last_pos = *pos;
2318 return rc;
2319 }
2320
2321 static void tcp_seq_stop(struct seq_file *seq, void *v)
2322 {
2323 struct tcp_iter_state *st = seq->private;
2324
2325 switch (st->state) {
2326 case TCP_SEQ_STATE_OPENREQ:
2327 if (v) {
2328 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2329 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2330 }
2331 case TCP_SEQ_STATE_LISTENING:
2332 if (v != SEQ_START_TOKEN)
2333 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2334 break;
2335 case TCP_SEQ_STATE_TIME_WAIT:
2336 case TCP_SEQ_STATE_ESTABLISHED:
2337 if (v)
2338 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2339 break;
2340 }
2341 }
2342
2343 int tcp_seq_open(struct inode *inode, struct file *file)
2344 {
2345 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2346 struct tcp_iter_state *s;
2347 int err;
2348
2349 err = seq_open_net(inode, file, &afinfo->seq_ops,
2350 sizeof(struct tcp_iter_state));
2351 if (err < 0)
2352 return err;
2353
2354 s = ((struct seq_file *)file->private_data)->private;
2355 s->family = afinfo->family;
2356 s->last_pos = 0;
2357 return 0;
2358 }
2359 EXPORT_SYMBOL(tcp_seq_open);
2360
2361 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2362 {
2363 int rc = 0;
2364 struct proc_dir_entry *p;
2365
2366 afinfo->seq_ops.start = tcp_seq_start;
2367 afinfo->seq_ops.next = tcp_seq_next;
2368 afinfo->seq_ops.stop = tcp_seq_stop;
2369
2370 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2371 afinfo->seq_fops, afinfo);
2372 if (!p)
2373 rc = -ENOMEM;
2374 return rc;
2375 }
2376 EXPORT_SYMBOL(tcp_proc_register);
2377
2378 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2379 {
2380 proc_net_remove(net, afinfo->name);
2381 }
2382 EXPORT_SYMBOL(tcp_proc_unregister);
2383
2384 static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2385 struct seq_file *f, int i, int uid, int *len)
2386 {
2387 const struct inet_request_sock *ireq = inet_rsk(req);
2388 int ttd = req->expires - jiffies;
2389
2390 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2391 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2392 i,
2393 ireq->loc_addr,
2394 ntohs(inet_sk(sk)->inet_sport),
2395 ireq->rmt_addr,
2396 ntohs(ireq->rmt_port),
2397 TCP_SYN_RECV,
2398 0, 0, /* could print option size, but that is af dependent. */
2399 1, /* timers active (only the expire timer) */
2400 jiffies_to_clock_t(ttd),
2401 req->retrans,
2402 uid,
2403 0, /* non standard timer */
2404 0, /* open_requests have no inode */
2405 atomic_read(&sk->sk_refcnt),
2406 req,
2407 len);
2408 }
2409
2410 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2411 {
2412 int timer_active;
2413 unsigned long timer_expires;
2414 const struct tcp_sock *tp = tcp_sk(sk);
2415 const struct inet_connection_sock *icsk = inet_csk(sk);
2416 const struct inet_sock *inet = inet_sk(sk);
2417 __be32 dest = inet->inet_daddr;
2418 __be32 src = inet->inet_rcv_saddr;
2419 __u16 destp = ntohs(inet->inet_dport);
2420 __u16 srcp = ntohs(inet->inet_sport);
2421 int rx_queue;
2422
2423 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2424 timer_active = 1;
2425 timer_expires = icsk->icsk_timeout;
2426 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2427 timer_active = 4;
2428 timer_expires = icsk->icsk_timeout;
2429 } else if (timer_pending(&sk->sk_timer)) {
2430 timer_active = 2;
2431 timer_expires = sk->sk_timer.expires;
2432 } else {
2433 timer_active = 0;
2434 timer_expires = jiffies;
2435 }
2436
2437 if (sk->sk_state == TCP_LISTEN)
2438 rx_queue = sk->sk_ack_backlog;
2439 else
2440 /*
2441 * because we dont lock socket, we might find a transient negative value
2442 */
2443 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2444
2445 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2446 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2447 i, src, srcp, dest, destp, sk->sk_state,
2448 tp->write_seq - tp->snd_una,
2449 rx_queue,
2450 timer_active,
2451 jiffies_to_clock_t(timer_expires - jiffies),
2452 icsk->icsk_retransmits,
2453 sock_i_uid(sk),
2454 icsk->icsk_probes_out,
2455 sock_i_ino(sk),
2456 atomic_read(&sk->sk_refcnt), sk,
2457 jiffies_to_clock_t(icsk->icsk_rto),
2458 jiffies_to_clock_t(icsk->icsk_ack.ato),
2459 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2460 tp->snd_cwnd,
2461 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2462 len);
2463 }
2464
2465 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2466 struct seq_file *f, int i, int *len)
2467 {
2468 __be32 dest, src;
2469 __u16 destp, srcp;
2470 int ttd = tw->tw_ttd - jiffies;
2471
2472 if (ttd < 0)
2473 ttd = 0;
2474
2475 dest = tw->tw_daddr;
2476 src = tw->tw_rcv_saddr;
2477 destp = ntohs(tw->tw_dport);
2478 srcp = ntohs(tw->tw_sport);
2479
2480 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2481 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2482 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2483 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2484 atomic_read(&tw->tw_refcnt), tw, len);
2485 }
2486
2487 #define TMPSZ 150
2488
2489 static int tcp4_seq_show(struct seq_file *seq, void *v)
2490 {
2491 struct tcp_iter_state *st;
2492 int len;
2493
2494 if (v == SEQ_START_TOKEN) {
2495 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2496 " sl local_address rem_address st tx_queue "
2497 "rx_queue tr tm->when retrnsmt uid timeout "
2498 "inode");
2499 goto out;
2500 }
2501 st = seq->private;
2502
2503 switch (st->state) {
2504 case TCP_SEQ_STATE_LISTENING:
2505 case TCP_SEQ_STATE_ESTABLISHED:
2506 get_tcp4_sock(v, seq, st->num, &len);
2507 break;
2508 case TCP_SEQ_STATE_OPENREQ:
2509 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2510 break;
2511 case TCP_SEQ_STATE_TIME_WAIT:
2512 get_timewait4_sock(v, seq, st->num, &len);
2513 break;
2514 }
2515 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2516 out:
2517 return 0;
2518 }
2519
2520 static const struct file_operations tcp_afinfo_seq_fops = {
2521 .owner = THIS_MODULE,
2522 .open = tcp_seq_open,
2523 .read = seq_read,
2524 .llseek = seq_lseek,
2525 .release = seq_release_net
2526 };
2527
2528 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2529 .name = "tcp",
2530 .family = AF_INET,
2531 .seq_fops = &tcp_afinfo_seq_fops,
2532 .seq_ops = {
2533 .show = tcp4_seq_show,
2534 },
2535 };
2536
2537 static int __net_init tcp4_proc_init_net(struct net *net)
2538 {
2539 return tcp_proc_register(net, &tcp4_seq_afinfo);
2540 }
2541
2542 static void __net_exit tcp4_proc_exit_net(struct net *net)
2543 {
2544 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2545 }
2546
2547 static struct pernet_operations tcp4_net_ops = {
2548 .init = tcp4_proc_init_net,
2549 .exit = tcp4_proc_exit_net,
2550 };
2551
2552 int __init tcp4_proc_init(void)
2553 {
2554 return register_pernet_subsys(&tcp4_net_ops);
2555 }
2556
2557 void tcp4_proc_exit(void)
2558 {
2559 unregister_pernet_subsys(&tcp4_net_ops);
2560 }
2561 #endif /* CONFIG_PROC_FS */
2562
2563 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2564 {
2565 const struct iphdr *iph = skb_gro_network_header(skb);
2566
2567 switch (skb->ip_summed) {
2568 case CHECKSUM_COMPLETE:
2569 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2570 skb->csum)) {
2571 skb->ip_summed = CHECKSUM_UNNECESSARY;
2572 break;
2573 }
2574
2575 /* fall through */
2576 case CHECKSUM_NONE:
2577 NAPI_GRO_CB(skb)->flush = 1;
2578 return NULL;
2579 }
2580
2581 return tcp_gro_receive(head, skb);
2582 }
2583
2584 int tcp4_gro_complete(struct sk_buff *skb)
2585 {
2586 const struct iphdr *iph = ip_hdr(skb);
2587 struct tcphdr *th = tcp_hdr(skb);
2588
2589 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2590 iph->saddr, iph->daddr, 0);
2591 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2592
2593 return tcp_gro_complete(skb);
2594 }
2595
2596 struct proto tcp_prot = {
2597 .name = "TCP",
2598 .owner = THIS_MODULE,
2599 .close = tcp_close,
2600 .connect = tcp_v4_connect,
2601 .disconnect = tcp_disconnect,
2602 .accept = inet_csk_accept,
2603 .ioctl = tcp_ioctl,
2604 .init = tcp_v4_init_sock,
2605 .destroy = tcp_v4_destroy_sock,
2606 .shutdown = tcp_shutdown,
2607 .setsockopt = tcp_setsockopt,
2608 .getsockopt = tcp_getsockopt,
2609 .recvmsg = tcp_recvmsg,
2610 .sendmsg = tcp_sendmsg,
2611 .sendpage = tcp_sendpage,
2612 .backlog_rcv = tcp_v4_do_rcv,
2613 .hash = inet_hash,
2614 .unhash = inet_unhash,
2615 .get_port = inet_csk_get_port,
2616 .enter_memory_pressure = tcp_enter_memory_pressure,
2617 .sockets_allocated = &tcp_sockets_allocated,
2618 .orphan_count = &tcp_orphan_count,
2619 .memory_allocated = &tcp_memory_allocated,
2620 .memory_pressure = &tcp_memory_pressure,
2621 .sysctl_mem = sysctl_tcp_mem,
2622 .sysctl_wmem = sysctl_tcp_wmem,
2623 .sysctl_rmem = sysctl_tcp_rmem,
2624 .max_header = MAX_TCP_HEADER,
2625 .obj_size = sizeof(struct tcp_sock),
2626 .slab_flags = SLAB_DESTROY_BY_RCU,
2627 .twsk_prot = &tcp_timewait_sock_ops,
2628 .rsk_prot = &tcp_request_sock_ops,
2629 .h.hashinfo = &tcp_hashinfo,
2630 .no_autobind = true,
2631 #ifdef CONFIG_COMPAT
2632 .compat_setsockopt = compat_tcp_setsockopt,
2633 .compat_getsockopt = compat_tcp_getsockopt,
2634 #endif
2635 };
2636 EXPORT_SYMBOL(tcp_prot);
2637
2638
2639 static int __net_init tcp_sk_init(struct net *net)
2640 {
2641 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2642 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2643 }
2644
2645 static void __net_exit tcp_sk_exit(struct net *net)
2646 {
2647 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2648 }
2649
2650 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2651 {
2652 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2653 }
2654
2655 static struct pernet_operations __net_initdata tcp_sk_ops = {
2656 .init = tcp_sk_init,
2657 .exit = tcp_sk_exit,
2658 .exit_batch = tcp_sk_exit_batch,
2659 };
2660
2661 void __init tcp_v4_init(void)
2662 {
2663 inet_hashinfo_init(&tcp_hashinfo);
2664 if (register_pernet_subsys(&tcp_sk_ops))
2665 panic("Failed to create the TCP control socket.\n");
2666 }