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tcp: md5: using remote adress for md5 lookup in rst packet
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv4 / tcp_ipv4.c
blobc89e354691368ba0046077c554e890f2dc0d995d
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)->saddr) : 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 tcp_clear_xmit_timers(newsk);
1514 bh_unlock_sock(newsk);
1515 sock_put(newsk);
1516 goto exit;
1517 }
1518 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1519
1520 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1521 {
1522 struct tcphdr *th = tcp_hdr(skb);
1523 const struct iphdr *iph = ip_hdr(skb);
1524 struct sock *nsk;
1525 struct request_sock **prev;
1526 /* Find possible connection requests. */
1527 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1528 iph->saddr, iph->daddr);
1529 if (req)
1530 return tcp_check_req(sk, skb, req, prev);
1531
1532 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1533 th->source, iph->daddr, th->dest, inet_iif(skb));
1534
1535 if (nsk) {
1536 if (nsk->sk_state != TCP_TIME_WAIT) {
1537 bh_lock_sock(nsk);
1538 return nsk;
1539 }
1540 inet_twsk_put(inet_twsk(nsk));
1541 return NULL;
1542 }
1543
1544 #ifdef CONFIG_SYN_COOKIES
1545 if (!th->syn)
1546 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1547 #endif
1548 return sk;
1549 }
1550
1551 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1552 {
1553 const struct iphdr *iph = ip_hdr(skb);
1554
1555 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1556 if (!tcp_v4_check(skb->len, iph->saddr,
1557 iph->daddr, skb->csum)) {
1558 skb->ip_summed = CHECKSUM_UNNECESSARY;
1559 return 0;
1560 }
1561 }
1562
1563 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1564 skb->len, IPPROTO_TCP, 0);
1565
1566 if (skb->len <= 76) {
1567 return __skb_checksum_complete(skb);
1568 }
1569 return 0;
1570 }
1571
1572
1573 /* The socket must have it's spinlock held when we get
1574 * here.
1575 *
1576 * We have a potential double-lock case here, so even when
1577 * doing backlog processing we use the BH locking scheme.
1578 * This is because we cannot sleep with the original spinlock
1579 * held.
1580 */
1581 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1582 {
1583 struct sock *rsk;
1584 #ifdef CONFIG_TCP_MD5SIG
1585 /*
1586 * We really want to reject the packet as early as possible
1587 * if:
1588 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1589 * o There is an MD5 option and we're not expecting one
1590 */
1591 if (tcp_v4_inbound_md5_hash(sk, skb))
1592 goto discard;
1593 #endif
1594
1595 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1596 sock_rps_save_rxhash(sk, skb);
1597 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1598 rsk = sk;
1599 goto reset;
1600 }
1601 return 0;
1602 }
1603
1604 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1605 goto csum_err;
1606
1607 if (sk->sk_state == TCP_LISTEN) {
1608 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1609 if (!nsk)
1610 goto discard;
1611
1612 if (nsk != sk) {
1613 sock_rps_save_rxhash(nsk, skb);
1614 if (tcp_child_process(sk, nsk, skb)) {
1615 rsk = nsk;
1616 goto reset;
1617 }
1618 return 0;
1619 }
1620 } else
1621 sock_rps_save_rxhash(sk, skb);
1622
1623 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1624 rsk = sk;
1625 goto reset;
1626 }
1627 return 0;
1628
1629 reset:
1630 tcp_v4_send_reset(rsk, skb);
1631 discard:
1632 kfree_skb(skb);
1633 /* Be careful here. If this function gets more complicated and
1634 * gcc suffers from register pressure on the x86, sk (in %ebx)
1635 * might be destroyed here. This current version compiles correctly,
1636 * but you have been warned.
1637 */
1638 return 0;
1639
1640 csum_err:
1641 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1642 goto discard;
1643 }
1644 EXPORT_SYMBOL(tcp_v4_do_rcv);
1645
1646 /*
1647 * From tcp_input.c
1648 */
1649
1650 int tcp_v4_rcv(struct sk_buff *skb)
1651 {
1652 const struct iphdr *iph;
1653 const struct tcphdr *th;
1654 struct sock *sk;
1655 int ret;
1656 struct net *net = dev_net(skb->dev);
1657
1658 if (skb->pkt_type != PACKET_HOST)
1659 goto discard_it;
1660
1661 /* Count it even if it's bad */
1662 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1663
1664 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1665 goto discard_it;
1666
1667 th = tcp_hdr(skb);
1668
1669 if (th->doff < sizeof(struct tcphdr) / 4)
1670 goto bad_packet;
1671 if (!pskb_may_pull(skb, th->doff * 4))
1672 goto discard_it;
1673
1674 /* An explanation is required here, I think.
1675 * Packet length and doff are validated by header prediction,
1676 * provided case of th->doff==0 is eliminated.
1677 * So, we defer the checks. */
1678 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1679 goto bad_packet;
1680
1681 th = tcp_hdr(skb);
1682 iph = ip_hdr(skb);
1683 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1684 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1685 skb->len - th->doff * 4);
1686 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1687 TCP_SKB_CB(skb)->when = 0;
1688 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1689 TCP_SKB_CB(skb)->sacked = 0;
1690
1691 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1692 if (!sk)
1693 goto no_tcp_socket;
1694
1695 process:
1696 if (sk->sk_state == TCP_TIME_WAIT)
1697 goto do_time_wait;
1698
1699 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1700 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1701 goto discard_and_relse;
1702 }
1703
1704 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1705 goto discard_and_relse;
1706 nf_reset(skb);
1707
1708 if (sk_filter(sk, skb))
1709 goto discard_and_relse;
1710
1711 skb->dev = NULL;
1712
1713 bh_lock_sock_nested(sk);
1714 ret = 0;
1715 if (!sock_owned_by_user(sk)) {
1716 #ifdef CONFIG_NET_DMA
1717 struct tcp_sock *tp = tcp_sk(sk);
1718 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1719 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1720 if (tp->ucopy.dma_chan)
1721 ret = tcp_v4_do_rcv(sk, skb);
1722 else
1723 #endif
1724 {
1725 if (!tcp_prequeue(sk, skb))
1726 ret = tcp_v4_do_rcv(sk, skb);
1727 }
1728 } else if (unlikely(sk_add_backlog(sk, skb))) {
1729 bh_unlock_sock(sk);
1730 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1731 goto discard_and_relse;
1732 }
1733 bh_unlock_sock(sk);
1734
1735 sock_put(sk);
1736
1737 return ret;
1738
1739 no_tcp_socket:
1740 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1741 goto discard_it;
1742
1743 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1744 bad_packet:
1745 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1746 } else {
1747 tcp_v4_send_reset(NULL, skb);
1748 }
1749
1750 discard_it:
1751 /* Discard frame. */
1752 kfree_skb(skb);
1753 return 0;
1754
1755 discard_and_relse:
1756 sock_put(sk);
1757 goto discard_it;
1758
1759 do_time_wait:
1760 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1761 inet_twsk_put(inet_twsk(sk));
1762 goto discard_it;
1763 }
1764
1765 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1766 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1767 inet_twsk_put(inet_twsk(sk));
1768 goto discard_it;
1769 }
1770 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1771 case TCP_TW_SYN: {
1772 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1773 &tcp_hashinfo,
1774 iph->daddr, th->dest,
1775 inet_iif(skb));
1776 if (sk2) {
1777 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1778 inet_twsk_put(inet_twsk(sk));
1779 sk = sk2;
1780 goto process;
1781 }
1782 /* Fall through to ACK */
1783 }
1784 case TCP_TW_ACK:
1785 tcp_v4_timewait_ack(sk, skb);
1786 break;
1787 case TCP_TW_RST:
1788 goto no_tcp_socket;
1789 case TCP_TW_SUCCESS:;
1790 }
1791 goto discard_it;
1792 }
1793
1794 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1795 {
1796 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1797 struct inet_sock *inet = inet_sk(sk);
1798 struct inet_peer *peer;
1799
1800 if (!rt ||
1801 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1802 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1803 *release_it = true;
1804 } else {
1805 if (!rt->peer)
1806 rt_bind_peer(rt, inet->inet_daddr, 1);
1807 peer = rt->peer;
1808 *release_it = false;
1809 }
1810
1811 return peer;
1812 }
1813 EXPORT_SYMBOL(tcp_v4_get_peer);
1814
1815 void *tcp_v4_tw_get_peer(struct sock *sk)
1816 {
1817 const struct inet_timewait_sock *tw = inet_twsk(sk);
1818
1819 return inet_getpeer_v4(tw->tw_daddr, 1);
1820 }
1821 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1822
1823 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1824 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1825 .twsk_unique = tcp_twsk_unique,
1826 .twsk_destructor= tcp_twsk_destructor,
1827 .twsk_getpeer = tcp_v4_tw_get_peer,
1828 };
1829
1830 const struct inet_connection_sock_af_ops ipv4_specific = {
1831 .queue_xmit = ip_queue_xmit,
1832 .send_check = tcp_v4_send_check,
1833 .rebuild_header = inet_sk_rebuild_header,
1834 .conn_request = tcp_v4_conn_request,
1835 .syn_recv_sock = tcp_v4_syn_recv_sock,
1836 .get_peer = tcp_v4_get_peer,
1837 .net_header_len = sizeof(struct iphdr),
1838 .setsockopt = ip_setsockopt,
1839 .getsockopt = ip_getsockopt,
1840 .addr2sockaddr = inet_csk_addr2sockaddr,
1841 .sockaddr_len = sizeof(struct sockaddr_in),
1842 .bind_conflict = inet_csk_bind_conflict,
1843 #ifdef CONFIG_COMPAT
1844 .compat_setsockopt = compat_ip_setsockopt,
1845 .compat_getsockopt = compat_ip_getsockopt,
1846 #endif
1847 };
1848 EXPORT_SYMBOL(ipv4_specific);
1849
1850 #ifdef CONFIG_TCP_MD5SIG
1851 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1852 .md5_lookup = tcp_v4_md5_lookup,
1853 .calc_md5_hash = tcp_v4_md5_hash_skb,
1854 .md5_add = tcp_v4_md5_add_func,
1855 .md5_parse = tcp_v4_parse_md5_keys,
1856 };
1857 #endif
1858
1859 /* NOTE: A lot of things set to zero explicitly by call to
1860 * sk_alloc() so need not be done here.
1861 */
1862 static int tcp_v4_init_sock(struct sock *sk)
1863 {
1864 struct inet_connection_sock *icsk = inet_csk(sk);
1865 struct tcp_sock *tp = tcp_sk(sk);
1866
1867 skb_queue_head_init(&tp->out_of_order_queue);
1868 tcp_init_xmit_timers(sk);
1869 tcp_prequeue_init(tp);
1870
1871 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1872 tp->mdev = TCP_TIMEOUT_INIT;
1873
1874 /* So many TCP implementations out there (incorrectly) count the
1875 * initial SYN frame in their delayed-ACK and congestion control
1876 * algorithms that we must have the following bandaid to talk
1877 * efficiently to them. -DaveM
1878 */
1879 tp->snd_cwnd = TCP_INIT_CWND;
1880
1881 /* See draft-stevens-tcpca-spec-01 for discussion of the
1882 * initialization of these values.
1883 */
1884 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1885 tp->snd_cwnd_clamp = ~0;
1886 tp->mss_cache = TCP_MSS_DEFAULT;
1887
1888 tp->reordering = sysctl_tcp_reordering;
1889 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1890
1891 sk->sk_state = TCP_CLOSE;
1892
1893 sk->sk_write_space = sk_stream_write_space;
1894 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1895
1896 icsk->icsk_af_ops = &ipv4_specific;
1897 icsk->icsk_sync_mss = tcp_sync_mss;
1898 #ifdef CONFIG_TCP_MD5SIG
1899 tp->af_specific = &tcp_sock_ipv4_specific;
1900 #endif
1901
1902 /* TCP Cookie Transactions */
1903 if (sysctl_tcp_cookie_size > 0) {
1904 /* Default, cookies without s_data_payload. */
1905 tp->cookie_values =
1906 kzalloc(sizeof(*tp->cookie_values),
1907 sk->sk_allocation);
1908 if (tp->cookie_values != NULL)
1909 kref_init(&tp->cookie_values->kref);
1910 }
1911 /* Presumed zeroed, in order of appearance:
1912 * cookie_in_always, cookie_out_never,
1913 * s_data_constant, s_data_in, s_data_out
1914 */
1915 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1916 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1917
1918 local_bh_disable();
1919 percpu_counter_inc(&tcp_sockets_allocated);
1920 local_bh_enable();
1921
1922 return 0;
1923 }
1924
1925 void tcp_v4_destroy_sock(struct sock *sk)
1926 {
1927 struct tcp_sock *tp = tcp_sk(sk);
1928
1929 tcp_clear_xmit_timers(sk);
1930
1931 tcp_cleanup_congestion_control(sk);
1932
1933 /* Cleanup up the write buffer. */
1934 tcp_write_queue_purge(sk);
1935
1936 /* Cleans up our, hopefully empty, out_of_order_queue. */
1937 __skb_queue_purge(&tp->out_of_order_queue);
1938
1939 #ifdef CONFIG_TCP_MD5SIG
1940 /* Clean up the MD5 key list, if any */
1941 if (tp->md5sig_info) {
1942 tcp_v4_clear_md5_list(sk);
1943 kfree(tp->md5sig_info);
1944 tp->md5sig_info = NULL;
1945 }
1946 #endif
1947
1948 #ifdef CONFIG_NET_DMA
1949 /* Cleans up our sk_async_wait_queue */
1950 __skb_queue_purge(&sk->sk_async_wait_queue);
1951 #endif
1952
1953 /* Clean prequeue, it must be empty really */
1954 __skb_queue_purge(&tp->ucopy.prequeue);
1955
1956 /* Clean up a referenced TCP bind bucket. */
1957 if (inet_csk(sk)->icsk_bind_hash)
1958 inet_put_port(sk);
1959
1960 /*
1961 * If sendmsg cached page exists, toss it.
1962 */
1963 if (sk->sk_sndmsg_page) {
1964 __free_page(sk->sk_sndmsg_page);
1965 sk->sk_sndmsg_page = NULL;
1966 }
1967
1968 /* TCP Cookie Transactions */
1969 if (tp->cookie_values != NULL) {
1970 kref_put(&tp->cookie_values->kref,
1971 tcp_cookie_values_release);
1972 tp->cookie_values = NULL;
1973 }
1974
1975 percpu_counter_dec(&tcp_sockets_allocated);
1976 }
1977 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1978
1979 #ifdef CONFIG_PROC_FS
1980 /* Proc filesystem TCP sock list dumping. */
1981
1982 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1983 {
1984 return hlist_nulls_empty(head) ? NULL :
1985 list_entry(head->first, struct inet_timewait_sock, tw_node);
1986 }
1987
1988 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1989 {
1990 return !is_a_nulls(tw->tw_node.next) ?
1991 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1992 }
1993
1994 /*
1995 * Get next listener socket follow cur. If cur is NULL, get first socket
1996 * starting from bucket given in st->bucket; when st->bucket is zero the
1997 * very first socket in the hash table is returned.
1998 */
1999 static void *listening_get_next(struct seq_file *seq, void *cur)
2000 {
2001 struct inet_connection_sock *icsk;
2002 struct hlist_nulls_node *node;
2003 struct sock *sk = cur;
2004 struct inet_listen_hashbucket *ilb;
2005 struct tcp_iter_state *st = seq->private;
2006 struct net *net = seq_file_net(seq);
2007
2008 if (!sk) {
2009 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2010 spin_lock_bh(&ilb->lock);
2011 sk = sk_nulls_head(&ilb->head);
2012 st->offset = 0;
2013 goto get_sk;
2014 }
2015 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2016 ++st->num;
2017 ++st->offset;
2018
2019 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2020 struct request_sock *req = cur;
2021
2022 icsk = inet_csk(st->syn_wait_sk);
2023 req = req->dl_next;
2024 while (1) {
2025 while (req) {
2026 if (req->rsk_ops->family == st->family) {
2027 cur = req;
2028 goto out;
2029 }
2030 req = req->dl_next;
2031 }
2032 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2033 break;
2034 get_req:
2035 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2036 }
2037 sk = sk_nulls_next(st->syn_wait_sk);
2038 st->state = TCP_SEQ_STATE_LISTENING;
2039 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2040 } else {
2041 icsk = inet_csk(sk);
2042 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2043 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2044 goto start_req;
2045 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2046 sk = sk_nulls_next(sk);
2047 }
2048 get_sk:
2049 sk_nulls_for_each_from(sk, node) {
2050 if (!net_eq(sock_net(sk), net))
2051 continue;
2052 if (sk->sk_family == st->family) {
2053 cur = sk;
2054 goto out;
2055 }
2056 icsk = inet_csk(sk);
2057 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2058 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2059 start_req:
2060 st->uid = sock_i_uid(sk);
2061 st->syn_wait_sk = sk;
2062 st->state = TCP_SEQ_STATE_OPENREQ;
2063 st->sbucket = 0;
2064 goto get_req;
2065 }
2066 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2067 }
2068 spin_unlock_bh(&ilb->lock);
2069 st->offset = 0;
2070 if (++st->bucket < INET_LHTABLE_SIZE) {
2071 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2072 spin_lock_bh(&ilb->lock);
2073 sk = sk_nulls_head(&ilb->head);
2074 goto get_sk;
2075 }
2076 cur = NULL;
2077 out:
2078 return cur;
2079 }
2080
2081 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2082 {
2083 struct tcp_iter_state *st = seq->private;
2084 void *rc;
2085
2086 st->bucket = 0;
2087 st->offset = 0;
2088 rc = listening_get_next(seq, NULL);
2089
2090 while (rc && *pos) {
2091 rc = listening_get_next(seq, rc);
2092 --*pos;
2093 }
2094 return rc;
2095 }
2096
2097 static inline int empty_bucket(struct tcp_iter_state *st)
2098 {
2099 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2100 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2101 }
2102
2103 /*
2104 * Get first established socket starting from bucket given in st->bucket.
2105 * If st->bucket is zero, the very first socket in the hash is returned.
2106 */
2107 static void *established_get_first(struct seq_file *seq)
2108 {
2109 struct tcp_iter_state *st = seq->private;
2110 struct net *net = seq_file_net(seq);
2111 void *rc = NULL;
2112
2113 st->offset = 0;
2114 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2115 struct sock *sk;
2116 struct hlist_nulls_node *node;
2117 struct inet_timewait_sock *tw;
2118 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2119
2120 /* Lockless fast path for the common case of empty buckets */
2121 if (empty_bucket(st))
2122 continue;
2123
2124 spin_lock_bh(lock);
2125 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2126 if (sk->sk_family != st->family ||
2127 !net_eq(sock_net(sk), net)) {
2128 continue;
2129 }
2130 rc = sk;
2131 goto out;
2132 }
2133 st->state = TCP_SEQ_STATE_TIME_WAIT;
2134 inet_twsk_for_each(tw, node,
2135 &tcp_hashinfo.ehash[st->bucket].twchain) {
2136 if (tw->tw_family != st->family ||
2137 !net_eq(twsk_net(tw), net)) {
2138 continue;
2139 }
2140 rc = tw;
2141 goto out;
2142 }
2143 spin_unlock_bh(lock);
2144 st->state = TCP_SEQ_STATE_ESTABLISHED;
2145 }
2146 out:
2147 return rc;
2148 }
2149
2150 static void *established_get_next(struct seq_file *seq, void *cur)
2151 {
2152 struct sock *sk = cur;
2153 struct inet_timewait_sock *tw;
2154 struct hlist_nulls_node *node;
2155 struct tcp_iter_state *st = seq->private;
2156 struct net *net = seq_file_net(seq);
2157
2158 ++st->num;
2159 ++st->offset;
2160
2161 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2162 tw = cur;
2163 tw = tw_next(tw);
2164 get_tw:
2165 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2166 tw = tw_next(tw);
2167 }
2168 if (tw) {
2169 cur = tw;
2170 goto out;
2171 }
2172 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2173 st->state = TCP_SEQ_STATE_ESTABLISHED;
2174
2175 /* Look for next non empty bucket */
2176 st->offset = 0;
2177 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2178 empty_bucket(st))
2179 ;
2180 if (st->bucket > tcp_hashinfo.ehash_mask)
2181 return NULL;
2182
2183 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2184 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2185 } else
2186 sk = sk_nulls_next(sk);
2187
2188 sk_nulls_for_each_from(sk, node) {
2189 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2190 goto found;
2191 }
2192
2193 st->state = TCP_SEQ_STATE_TIME_WAIT;
2194 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2195 goto get_tw;
2196 found:
2197 cur = sk;
2198 out:
2199 return cur;
2200 }
2201
2202 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2203 {
2204 struct tcp_iter_state *st = seq->private;
2205 void *rc;
2206
2207 st->bucket = 0;
2208 rc = established_get_first(seq);
2209
2210 while (rc && pos) {
2211 rc = established_get_next(seq, rc);
2212 --pos;
2213 }
2214 return rc;
2215 }
2216
2217 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2218 {
2219 void *rc;
2220 struct tcp_iter_state *st = seq->private;
2221
2222 st->state = TCP_SEQ_STATE_LISTENING;
2223 rc = listening_get_idx(seq, &pos);
2224
2225 if (!rc) {
2226 st->state = TCP_SEQ_STATE_ESTABLISHED;
2227 rc = established_get_idx(seq, pos);
2228 }
2229
2230 return rc;
2231 }
2232
2233 static void *tcp_seek_last_pos(struct seq_file *seq)
2234 {
2235 struct tcp_iter_state *st = seq->private;
2236 int offset = st->offset;
2237 int orig_num = st->num;
2238 void *rc = NULL;
2239
2240 switch (st->state) {
2241 case TCP_SEQ_STATE_OPENREQ:
2242 case TCP_SEQ_STATE_LISTENING:
2243 if (st->bucket >= INET_LHTABLE_SIZE)
2244 break;
2245 st->state = TCP_SEQ_STATE_LISTENING;
2246 rc = listening_get_next(seq, NULL);
2247 while (offset-- && rc)
2248 rc = listening_get_next(seq, rc);
2249 if (rc)
2250 break;
2251 st->bucket = 0;
2252 /* Fallthrough */
2253 case TCP_SEQ_STATE_ESTABLISHED:
2254 case TCP_SEQ_STATE_TIME_WAIT:
2255 st->state = TCP_SEQ_STATE_ESTABLISHED;
2256 if (st->bucket > tcp_hashinfo.ehash_mask)
2257 break;
2258 rc = established_get_first(seq);
2259 while (offset-- && rc)
2260 rc = established_get_next(seq, rc);
2261 }
2262
2263 st->num = orig_num;
2264
2265 return rc;
2266 }
2267
2268 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2269 {
2270 struct tcp_iter_state *st = seq->private;
2271 void *rc;
2272
2273 if (*pos && *pos == st->last_pos) {
2274 rc = tcp_seek_last_pos(seq);
2275 if (rc)
2276 goto out;
2277 }
2278
2279 st->state = TCP_SEQ_STATE_LISTENING;
2280 st->num = 0;
2281 st->bucket = 0;
2282 st->offset = 0;
2283 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2284
2285 out:
2286 st->last_pos = *pos;
2287 return rc;
2288 }
2289
2290 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2291 {
2292 struct tcp_iter_state *st = seq->private;
2293 void *rc = NULL;
2294
2295 if (v == SEQ_START_TOKEN) {
2296 rc = tcp_get_idx(seq, 0);
2297 goto out;
2298 }
2299
2300 switch (st->state) {
2301 case TCP_SEQ_STATE_OPENREQ:
2302 case TCP_SEQ_STATE_LISTENING:
2303 rc = listening_get_next(seq, v);
2304 if (!rc) {
2305 st->state = TCP_SEQ_STATE_ESTABLISHED;
2306 st->bucket = 0;
2307 st->offset = 0;
2308 rc = established_get_first(seq);
2309 }
2310 break;
2311 case TCP_SEQ_STATE_ESTABLISHED:
2312 case TCP_SEQ_STATE_TIME_WAIT:
2313 rc = established_get_next(seq, v);
2314 break;
2315 }
2316 out:
2317 ++*pos;
2318 st->last_pos = *pos;
2319 return rc;
2320 }
2321
2322 static void tcp_seq_stop(struct seq_file *seq, void *v)
2323 {
2324 struct tcp_iter_state *st = seq->private;
2325
2326 switch (st->state) {
2327 case TCP_SEQ_STATE_OPENREQ:
2328 if (v) {
2329 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2330 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2331 }
2332 case TCP_SEQ_STATE_LISTENING:
2333 if (v != SEQ_START_TOKEN)
2334 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2335 break;
2336 case TCP_SEQ_STATE_TIME_WAIT:
2337 case TCP_SEQ_STATE_ESTABLISHED:
2338 if (v)
2339 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2340 break;
2341 }
2342 }
2343
2344 int tcp_seq_open(struct inode *inode, struct file *file)
2345 {
2346 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2347 struct tcp_iter_state *s;
2348 int err;
2349
2350 err = seq_open_net(inode, file, &afinfo->seq_ops,
2351 sizeof(struct tcp_iter_state));
2352 if (err < 0)
2353 return err;
2354
2355 s = ((struct seq_file *)file->private_data)->private;
2356 s->family = afinfo->family;
2357 s->last_pos = 0;
2358 return 0;
2359 }
2360 EXPORT_SYMBOL(tcp_seq_open);
2361
2362 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2363 {
2364 int rc = 0;
2365 struct proc_dir_entry *p;
2366
2367 afinfo->seq_ops.start = tcp_seq_start;
2368 afinfo->seq_ops.next = tcp_seq_next;
2369 afinfo->seq_ops.stop = tcp_seq_stop;
2370
2371 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2372 afinfo->seq_fops, afinfo);
2373 if (!p)
2374 rc = -ENOMEM;
2375 return rc;
2376 }
2377 EXPORT_SYMBOL(tcp_proc_register);
2378
2379 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2380 {
2381 proc_net_remove(net, afinfo->name);
2382 }
2383 EXPORT_SYMBOL(tcp_proc_unregister);
2384
2385 static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2386 struct seq_file *f, int i, int uid, int *len)
2387 {
2388 const struct inet_request_sock *ireq = inet_rsk(req);
2389 int ttd = req->expires - jiffies;
2390
2391 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2392 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2393 i,
2394 ireq->loc_addr,
2395 ntohs(inet_sk(sk)->inet_sport),
2396 ireq->rmt_addr,
2397 ntohs(ireq->rmt_port),
2398 TCP_SYN_RECV,
2399 0, 0, /* could print option size, but that is af dependent. */
2400 1, /* timers active (only the expire timer) */
2401 jiffies_to_clock_t(ttd),
2402 req->retrans,
2403 uid,
2404 0, /* non standard timer */
2405 0, /* open_requests have no inode */
2406 atomic_read(&sk->sk_refcnt),
2407 req,
2408 len);
2409 }
2410
2411 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2412 {
2413 int timer_active;
2414 unsigned long timer_expires;
2415 const struct tcp_sock *tp = tcp_sk(sk);
2416 const struct inet_connection_sock *icsk = inet_csk(sk);
2417 const struct inet_sock *inet = inet_sk(sk);
2418 __be32 dest = inet->inet_daddr;
2419 __be32 src = inet->inet_rcv_saddr;
2420 __u16 destp = ntohs(inet->inet_dport);
2421 __u16 srcp = ntohs(inet->inet_sport);
2422 int rx_queue;
2423
2424 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2425 timer_active = 1;
2426 timer_expires = icsk->icsk_timeout;
2427 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2428 timer_active = 4;
2429 timer_expires = icsk->icsk_timeout;
2430 } else if (timer_pending(&sk->sk_timer)) {
2431 timer_active = 2;
2432 timer_expires = sk->sk_timer.expires;
2433 } else {
2434 timer_active = 0;
2435 timer_expires = jiffies;
2436 }
2437
2438 if (sk->sk_state == TCP_LISTEN)
2439 rx_queue = sk->sk_ack_backlog;
2440 else
2441 /*
2442 * because we dont lock socket, we might find a transient negative value
2443 */
2444 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2445
2446 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2447 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2448 i, src, srcp, dest, destp, sk->sk_state,
2449 tp->write_seq - tp->snd_una,
2450 rx_queue,
2451 timer_active,
2452 jiffies_to_clock_t(timer_expires - jiffies),
2453 icsk->icsk_retransmits,
2454 sock_i_uid(sk),
2455 icsk->icsk_probes_out,
2456 sock_i_ino(sk),
2457 atomic_read(&sk->sk_refcnt), sk,
2458 jiffies_to_clock_t(icsk->icsk_rto),
2459 jiffies_to_clock_t(icsk->icsk_ack.ato),
2460 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2461 tp->snd_cwnd,
2462 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2463 len);
2464 }
2465
2466 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2467 struct seq_file *f, int i, int *len)
2468 {
2469 __be32 dest, src;
2470 __u16 destp, srcp;
2471 int ttd = tw->tw_ttd - jiffies;
2472
2473 if (ttd < 0)
2474 ttd = 0;
2475
2476 dest = tw->tw_daddr;
2477 src = tw->tw_rcv_saddr;
2478 destp = ntohs(tw->tw_dport);
2479 srcp = ntohs(tw->tw_sport);
2480
2481 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2482 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2483 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2484 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2485 atomic_read(&tw->tw_refcnt), tw, len);
2486 }
2487
2488 #define TMPSZ 150
2489
2490 static int tcp4_seq_show(struct seq_file *seq, void *v)
2491 {
2492 struct tcp_iter_state *st;
2493 int len;
2494
2495 if (v == SEQ_START_TOKEN) {
2496 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2497 " sl local_address rem_address st tx_queue "
2498 "rx_queue tr tm->when retrnsmt uid timeout "
2499 "inode");
2500 goto out;
2501 }
2502 st = seq->private;
2503
2504 switch (st->state) {
2505 case TCP_SEQ_STATE_LISTENING:
2506 case TCP_SEQ_STATE_ESTABLISHED:
2507 get_tcp4_sock(v, seq, st->num, &len);
2508 break;
2509 case TCP_SEQ_STATE_OPENREQ:
2510 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2511 break;
2512 case TCP_SEQ_STATE_TIME_WAIT:
2513 get_timewait4_sock(v, seq, st->num, &len);
2514 break;
2515 }
2516 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2517 out:
2518 return 0;
2519 }
2520
2521 static const struct file_operations tcp_afinfo_seq_fops = {
2522 .owner = THIS_MODULE,
2523 .open = tcp_seq_open,
2524 .read = seq_read,
2525 .llseek = seq_lseek,
2526 .release = seq_release_net
2527 };
2528
2529 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2530 .name = "tcp",
2531 .family = AF_INET,
2532 .seq_fops = &tcp_afinfo_seq_fops,
2533 .seq_ops = {
2534 .show = tcp4_seq_show,
2535 },
2536 };
2537
2538 static int __net_init tcp4_proc_init_net(struct net *net)
2539 {
2540 return tcp_proc_register(net, &tcp4_seq_afinfo);
2541 }
2542
2543 static void __net_exit tcp4_proc_exit_net(struct net *net)
2544 {
2545 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2546 }
2547
2548 static struct pernet_operations tcp4_net_ops = {
2549 .init = tcp4_proc_init_net,
2550 .exit = tcp4_proc_exit_net,
2551 };
2552
2553 int __init tcp4_proc_init(void)
2554 {
2555 return register_pernet_subsys(&tcp4_net_ops);
2556 }
2557
2558 void tcp4_proc_exit(void)
2559 {
2560 unregister_pernet_subsys(&tcp4_net_ops);
2561 }
2562 #endif /* CONFIG_PROC_FS */
2563
2564 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2565 {
2566 const struct iphdr *iph = skb_gro_network_header(skb);
2567
2568 switch (skb->ip_summed) {
2569 case CHECKSUM_COMPLETE:
2570 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2571 skb->csum)) {
2572 skb->ip_summed = CHECKSUM_UNNECESSARY;
2573 break;
2574 }
2575
2576 /* fall through */
2577 case CHECKSUM_NONE:
2578 NAPI_GRO_CB(skb)->flush = 1;
2579 return NULL;
2580 }
2581
2582 return tcp_gro_receive(head, skb);
2583 }
2584
2585 int tcp4_gro_complete(struct sk_buff *skb)
2586 {
2587 const struct iphdr *iph = ip_hdr(skb);
2588 struct tcphdr *th = tcp_hdr(skb);
2589
2590 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2591 iph->saddr, iph->daddr, 0);
2592 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2593
2594 return tcp_gro_complete(skb);
2595 }
2596
2597 struct proto tcp_prot = {
2598 .name = "TCP",
2599 .owner = THIS_MODULE,
2600 .close = tcp_close,
2601 .connect = tcp_v4_connect,
2602 .disconnect = tcp_disconnect,
2603 .accept = inet_csk_accept,
2604 .ioctl = tcp_ioctl,
2605 .init = tcp_v4_init_sock,
2606 .destroy = tcp_v4_destroy_sock,
2607 .shutdown = tcp_shutdown,
2608 .setsockopt = tcp_setsockopt,
2609 .getsockopt = tcp_getsockopt,
2610 .recvmsg = tcp_recvmsg,
2611 .sendmsg = tcp_sendmsg,
2612 .sendpage = tcp_sendpage,
2613 .backlog_rcv = tcp_v4_do_rcv,
2614 .hash = inet_hash,
2615 .unhash = inet_unhash,
2616 .get_port = inet_csk_get_port,
2617 .enter_memory_pressure = tcp_enter_memory_pressure,
2618 .sockets_allocated = &tcp_sockets_allocated,
2619 .orphan_count = &tcp_orphan_count,
2620 .memory_allocated = &tcp_memory_allocated,
2621 .memory_pressure = &tcp_memory_pressure,
2622 .sysctl_mem = sysctl_tcp_mem,
2623 .sysctl_wmem = sysctl_tcp_wmem,
2624 .sysctl_rmem = sysctl_tcp_rmem,
2625 .max_header = MAX_TCP_HEADER,
2626 .obj_size = sizeof(struct tcp_sock),
2627 .slab_flags = SLAB_DESTROY_BY_RCU,
2628 .twsk_prot = &tcp_timewait_sock_ops,
2629 .rsk_prot = &tcp_request_sock_ops,
2630 .h.hashinfo = &tcp_hashinfo,
2631 .no_autobind = true,
2632 #ifdef CONFIG_COMPAT
2633 .compat_setsockopt = compat_tcp_setsockopt,
2634 .compat_getsockopt = compat_tcp_getsockopt,
2635 #endif
2636 };
2637 EXPORT_SYMBOL(tcp_prot);
2638
2639
2640 static int __net_init tcp_sk_init(struct net *net)
2641 {
2642 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2643 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2644 }
2645
2646 static void __net_exit tcp_sk_exit(struct net *net)
2647 {
2648 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2649 }
2650
2651 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2652 {
2653 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2654 }
2655
2656 static struct pernet_operations __net_initdata tcp_sk_ops = {
2657 .init = tcp_sk_init,
2658 .exit = tcp_sk_exit,
2659 .exit_batch = tcp_sk_exit_batch,
2660 };
2661
2662 void __init tcp_v4_init(void)
2663 {
2664 inet_hashinfo_init(&tcp_hashinfo);
2665 if (register_pernet_subsys(&tcp_sk_ops))
2666 panic("Failed to create the TCP control socket.\n");
2667 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree