1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24 /*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53
54 #include <linux/bottom_half.h>
55 #include <linux/types.h>
56 #include <linux/fcntl.h>
57 #include <linux/module.h>
58 #include <linux/random.h>
59 #include <linux/cache.h>
60 #include <linux/jhash.h>
61 #include <linux/init.h>
62 #include <linux/times.h>
63
64 #include <net/net_namespace.h>
65 #include <net/icmp.h>
66 #include <net/inet_hashtables.h>
67 #include <net/tcp.h>
68 #include <net/transp_v6.h>
69 #include <net/ipv6.h>
70 #include <net/inet_common.h>
71 #include <net/timewait_sock.h>
72 #include <net/xfrm.h>
73 #include <net/netdma.h>
74
75 #include <linux/inet.h>
76 #include <linux/ipv6.h>
77 #include <linux/stddef.h>
78 #include <linux/proc_fs.h>
79 #include <linux/seq_file.h>
80
81 #include <linux/crypto.h>
82 #include <linux/scatterlist.h>
83
84 int sysctl_tcp_tw_reuse __read_mostly;
85 int sysctl_tcp_low_latency __read_mostly;
86
87
88 #ifdef CONFIG_TCP_MD5SIG
89 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
90 __be32 addr);
91 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
92 __be32 daddr, __be32 saddr, struct tcphdr *th);
93 #else
94 static inline
tcp_v4_md5_do_lookup(struct sock * sk,__be32 addr)95 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
96 {
97 return NULL;
98 }
99 #endif
100
101 struct inet_hashinfo tcp_hashinfo;
102
tcp_v4_init_sequence(struct sk_buff * skb)103 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
104 {
105 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
106 ip_hdr(skb)->saddr,
107 tcp_hdr(skb)->dest,
108 tcp_hdr(skb)->source);
109 }
110
tcp_twsk_unique(struct sock * sk,struct sock * sktw,void * twp)111 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112 {
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 /* With PAWS, it is safe from the viewpoint
117 of data integrity. Even without PAWS it is safe provided sequence
118 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119
120 Actually, the idea is close to VJ's one, only timestamp cache is
121 held not per host, but per port pair and TW bucket is used as state
122 holder.
123
124 If TW bucket has been already destroyed we fall back to VJ's scheme
125 and use initial timestamp retrieved from peer table.
126 */
127 if (tcptw->tw_ts_recent_stamp &&
128 (twp == NULL || (sysctl_tcp_tw_reuse &&
129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
131 if (tp->write_seq == 0)
132 tp->write_seq = 1;
133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
135 sock_hold(sktw);
136 return 1;
137 }
138
139 return 0;
140 }
141
142 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
143
144 /* This will initiate an outgoing connection. */
tcp_v4_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)145 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
146 {
147 struct inet_sock *inet = inet_sk(sk);
148 struct tcp_sock *tp = tcp_sk(sk);
149 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
150 struct rtable *rt;
151 __be32 daddr, nexthop;
152 int tmp;
153 int err;
154
155 if (addr_len < sizeof(struct sockaddr_in))
156 return -EINVAL;
157
158 if (usin->sin_family != AF_INET)
159 return -EAFNOSUPPORT;
160
161 nexthop = daddr = usin->sin_addr.s_addr;
162 if (inet->opt && inet->opt->srr) {
163 if (!daddr)
164 return -EINVAL;
165 nexthop = inet->opt->faddr;
166 }
167
168 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
169 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
170 IPPROTO_TCP,
171 inet->sport, usin->sin_port, sk, 1);
172 if (tmp < 0) {
173 if (tmp == -ENETUNREACH)
174 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
175 return tmp;
176 }
177
178 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
179 ip_rt_put(rt);
180 return -ENETUNREACH;
181 }
182
183 if (!inet->opt || !inet->opt->srr)
184 daddr = rt->rt_dst;
185
186 if (!inet->saddr)
187 inet->saddr = rt->rt_src;
188 inet->rcv_saddr = inet->saddr;
189
190 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
191 /* Reset inherited state */
192 tp->rx_opt.ts_recent = 0;
193 tp->rx_opt.ts_recent_stamp = 0;
194 tp->write_seq = 0;
195 }
196
197 if (tcp_death_row.sysctl_tw_recycle &&
198 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
199 struct inet_peer *peer = rt_get_peer(rt);
200 /*
201 * VJ's idea. We save last timestamp seen from
202 * the destination in peer table, when entering state
203 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
204 * when trying new connection.
205 */
206 if (peer != NULL &&
207 peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
208 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
209 tp->rx_opt.ts_recent = peer->tcp_ts;
210 }
211 }
212
213 inet->dport = usin->sin_port;
214 inet->daddr = daddr;
215
216 inet_csk(sk)->icsk_ext_hdr_len = 0;
217 if (inet->opt)
218 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
219
220 tp->rx_opt.mss_clamp = 536;
221
222 /* Socket identity is still unknown (sport may be zero).
223 * However we set state to SYN-SENT and not releasing socket
224 * lock select source port, enter ourselves into the hash tables and
225 * complete initialization after this.
226 */
227 tcp_set_state(sk, TCP_SYN_SENT);
228 err = inet_hash_connect(&tcp_death_row, sk);
229 if (err)
230 goto failure;
231
232 err = ip_route_newports(&rt, IPPROTO_TCP,
233 inet->sport, inet->dport, sk);
234 if (err)
235 goto failure;
236
237 /* OK, now commit destination to socket. */
238 sk->sk_gso_type = SKB_GSO_TCPV4;
239 sk_setup_caps(sk, &rt->u.dst);
240
241 if (!tp->write_seq)
242 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
243 inet->daddr,
244 inet->sport,
245 usin->sin_port);
246
247 inet->id = tp->write_seq ^ jiffies;
248
249 err = tcp_connect(sk);
250 rt = NULL;
251 if (err)
252 goto failure;
253
254 return 0;
255
256 failure:
257 /*
258 * This unhashes the socket and releases the local port,
259 * if necessary.
260 */
261 tcp_set_state(sk, TCP_CLOSE);
262 ip_rt_put(rt);
263 sk->sk_route_caps = 0;
264 inet->dport = 0;
265 return err;
266 }
267
268 /*
269 * This routine does path mtu discovery as defined in RFC1191.
270 */
do_pmtu_discovery(struct sock * sk,struct iphdr * iph,u32 mtu)271 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
272 {
273 struct dst_entry *dst;
274 struct inet_sock *inet = inet_sk(sk);
275
276 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
277 * send out by Linux are always <576bytes so they should go through
278 * unfragmented).
279 */
280 if (sk->sk_state == TCP_LISTEN)
281 return;
282
283 /* We don't check in the destentry if pmtu discovery is forbidden
284 * on this route. We just assume that no packet_to_big packets
285 * are send back when pmtu discovery is not active.
286 * There is a small race when the user changes this flag in the
287 * route, but I think that's acceptable.
288 */
289 if ((dst = __sk_dst_check(sk, 0)) == NULL)
290 return;
291
292 dst->ops->update_pmtu(dst, mtu);
293
294 /* Something is about to be wrong... Remember soft error
295 * for the case, if this connection will not able to recover.
296 */
297 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
298 sk->sk_err_soft = EMSGSIZE;
299
300 mtu = dst_mtu(dst);
301
302 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
303 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
304 tcp_sync_mss(sk, mtu);
305
306 /* Resend the TCP packet because it's
307 * clear that the old packet has been
308 * dropped. This is the new "fast" path mtu
309 * discovery.
310 */
311 tcp_simple_retransmit(sk);
312 } /* else let the usual retransmit timer handle it */
313 }
314
315 /*
316 * This routine is called by the ICMP module when it gets some
317 * sort of error condition. If err < 0 then the socket should
318 * be closed and the error returned to the user. If err > 0
319 * it's just the icmp type << 8 | icmp code. After adjustment
320 * header points to the first 8 bytes of the tcp header. We need
321 * to find the appropriate port.
322 *
323 * The locking strategy used here is very "optimistic". When
324 * someone else accesses the socket the ICMP is just dropped
325 * and for some paths there is no check at all.
326 * A more general error queue to queue errors for later handling
327 * is probably better.
328 *
329 */
330
tcp_v4_err(struct sk_buff * skb,u32 info)331 void tcp_v4_err(struct sk_buff *skb, u32 info)
332 {
333 struct iphdr *iph = (struct iphdr *)skb->data;
334 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
335 struct tcp_sock *tp;
336 struct inet_sock *inet;
337 const int type = icmp_hdr(skb)->type;
338 const int code = icmp_hdr(skb)->code;
339 struct sock *sk;
340 __u32 seq;
341 int err;
342 struct net *net = dev_net(skb->dev);
343
344 if (skb->len < (iph->ihl << 2) + 8) {
345 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
346 return;
347 }
348
349 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
350 iph->saddr, th->source, inet_iif(skb));
351 if (!sk) {
352 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
353 return;
354 }
355 if (sk->sk_state == TCP_TIME_WAIT) {
356 inet_twsk_put(inet_twsk(sk));
357 return;
358 }
359
360 bh_lock_sock(sk);
361 /* If too many ICMPs get dropped on busy
362 * servers this needs to be solved differently.
363 */
364 if (sock_owned_by_user(sk))
365 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
366
367 if (sk->sk_state == TCP_CLOSE)
368 goto out;
369
370 tp = tcp_sk(sk);
371 seq = ntohl(th->seq);
372 if (sk->sk_state != TCP_LISTEN &&
373 !between(seq, tp->snd_una, tp->snd_nxt)) {
374 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
375 goto out;
376 }
377
378 switch (type) {
379 case ICMP_SOURCE_QUENCH:
380 /* Just silently ignore these. */
381 goto out;
382 case ICMP_PARAMETERPROB:
383 err = EPROTO;
384 break;
385 case ICMP_DEST_UNREACH:
386 if (code > NR_ICMP_UNREACH)
387 goto out;
388
389 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
390 if (!sock_owned_by_user(sk))
391 do_pmtu_discovery(sk, iph, info);
392 goto out;
393 }
394
395 err = icmp_err_convert[code].errno;
396 break;
397 case ICMP_TIME_EXCEEDED:
398 err = EHOSTUNREACH;
399 break;
400 default:
401 goto out;
402 }
403
404 switch (sk->sk_state) {
405 struct request_sock *req, **prev;
406 case TCP_LISTEN:
407 if (sock_owned_by_user(sk))
408 goto out;
409
410 req = inet_csk_search_req(sk, &prev, th->dest,
411 iph->daddr, iph->saddr);
412 if (!req)
413 goto out;
414
415 /* ICMPs are not backlogged, hence we cannot get
416 an established socket here.
417 */
418 WARN_ON(req->sk);
419
420 if (seq != tcp_rsk(req)->snt_isn) {
421 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
422 goto out;
423 }
424
425 /*
426 * Still in SYN_RECV, just remove it silently.
427 * There is no good way to pass the error to the newly
428 * created socket, and POSIX does not want network
429 * errors returned from accept().
430 */
431 inet_csk_reqsk_queue_drop(sk, req, prev);
432 goto out;
433
434 case TCP_SYN_SENT:
435 case TCP_SYN_RECV: /* Cannot happen.
436 It can f.e. if SYNs crossed.
437 */
438 if (!sock_owned_by_user(sk)) {
439 sk->sk_err = err;
440
441 sk->sk_error_report(sk);
442
443 tcp_done(sk);
444 } else {
445 sk->sk_err_soft = err;
446 }
447 goto out;
448 }
449
450 /* If we've already connected we will keep trying
451 * until we time out, or the user gives up.
452 *
453 * rfc1122 4.2.3.9 allows to consider as hard errors
454 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
455 * but it is obsoleted by pmtu discovery).
456 *
457 * Note, that in modern internet, where routing is unreliable
458 * and in each dark corner broken firewalls sit, sending random
459 * errors ordered by their masters even this two messages finally lose
460 * their original sense (even Linux sends invalid PORT_UNREACHs)
461 *
462 * Now we are in compliance with RFCs.
463 * --ANK (980905)
464 */
465
466 inet = inet_sk(sk);
467 if (!sock_owned_by_user(sk) && inet->recverr) {
468 sk->sk_err = err;
469 sk->sk_error_report(sk);
470 } else { /* Only an error on timeout */
471 sk->sk_err_soft = err;
472 }
473
474 out:
475 bh_unlock_sock(sk);
476 sock_put(sk);
477 }
478
479 /* This routine computes an IPv4 TCP checksum. */
tcp_v4_send_check(struct sock * sk,int len,struct sk_buff * skb)480 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
481 {
482 struct inet_sock *inet = inet_sk(sk);
483 struct tcphdr *th = tcp_hdr(skb);
484
485 if (skb->ip_summed == CHECKSUM_PARTIAL) {
486 th->check = ~tcp_v4_check(len, inet->saddr,
487 inet->daddr, 0);
488 skb->csum_start = skb_transport_header(skb) - skb->head;
489 skb->csum_offset = offsetof(struct tcphdr, check);
490 } else {
491 th->check = tcp_v4_check(len, inet->saddr, inet->daddr,
492 csum_partial(th,
493 th->doff << 2,
494 skb->csum));
495 }
496 }
497
tcp_v4_gso_send_check(struct sk_buff * skb)498 int tcp_v4_gso_send_check(struct sk_buff *skb)
499 {
500 const struct iphdr *iph;
501 struct tcphdr *th;
502
503 if (!pskb_may_pull(skb, sizeof(*th)))
504 return -EINVAL;
505
506 iph = ip_hdr(skb);
507 th = tcp_hdr(skb);
508
509 th->check = 0;
510 th->check = ~tcp_v4_check(skb->len, iph->saddr, iph->daddr, 0);
511 skb->csum_start = skb_transport_header(skb) - skb->head;
512 skb->csum_offset = offsetof(struct tcphdr, check);
513 skb->ip_summed = CHECKSUM_PARTIAL;
514 return 0;
515 }
516
517 /*
518 * This routine will send an RST to the other tcp.
519 *
520 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
521 * for reset.
522 * Answer: if a packet caused RST, it is not for a socket
523 * existing in our system, if it is matched to a socket,
524 * it is just duplicate segment or bug in other side's TCP.
525 * So that we build reply only basing on parameters
526 * arrived with segment.
527 * Exception: precedence violation. We do not implement it in any case.
528 */
529
tcp_v4_send_reset(struct sock * sk,struct sk_buff * skb)530 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
531 {
532 struct tcphdr *th = tcp_hdr(skb);
533 struct {
534 struct tcphdr th;
535 #ifdef CONFIG_TCP_MD5SIG
536 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
537 #endif
538 } rep;
539 struct ip_reply_arg arg;
540 #ifdef CONFIG_TCP_MD5SIG
541 struct tcp_md5sig_key *key;
542 #endif
543 struct net *net;
544
545 /* Never send a reset in response to a reset. */
546 if (th->rst)
547 return;
548
549 if (skb->rtable->rt_type != RTN_LOCAL)
550 return;
551
552 /* Swap the send and the receive. */
553 memset(&rep, 0, sizeof(rep));
554 rep.th.dest = th->source;
555 rep.th.source = th->dest;
556 rep.th.doff = sizeof(struct tcphdr) / 4;
557 rep.th.rst = 1;
558
559 if (th->ack) {
560 rep.th.seq = th->ack_seq;
561 } else {
562 rep.th.ack = 1;
563 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
564 skb->len - (th->doff << 2));
565 }
566
567 memset(&arg, 0, sizeof(arg));
568 arg.iov[0].iov_base = (unsigned char *)&rep;
569 arg.iov[0].iov_len = sizeof(rep.th);
570
571 #ifdef CONFIG_TCP_MD5SIG
572 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
573 if (key) {
574 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
575 (TCPOPT_NOP << 16) |
576 (TCPOPT_MD5SIG << 8) |
577 TCPOLEN_MD5SIG);
578 /* Update length and the length the header thinks exists */
579 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
580 rep.th.doff = arg.iov[0].iov_len / 4;
581
582 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
583 key, ip_hdr(skb)->saddr,
584 ip_hdr(skb)->daddr, &rep.th);
585 }
586 #endif
587 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
588 ip_hdr(skb)->saddr, /* XXX */
589 arg.iov[0].iov_len, IPPROTO_TCP, 0);
590 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
591 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
592
593 net = dev_net(skb->dst->dev);
594 ip_send_reply(net->ipv4.tcp_sock, skb,
595 &arg, arg.iov[0].iov_len);
596
597 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
598 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
599 }
600
601 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
602 outside socket context is ugly, certainly. What can I do?
603 */
604
tcp_v4_send_ack(struct sk_buff * skb,u32 seq,u32 ack,u32 win,u32 ts,int oif,struct tcp_md5sig_key * key,int reply_flags)605 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
606 u32 win, u32 ts, int oif,
607 struct tcp_md5sig_key *key,
608 int reply_flags)
609 {
610 struct tcphdr *th = tcp_hdr(skb);
611 struct {
612 struct tcphdr th;
613 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
614 #ifdef CONFIG_TCP_MD5SIG
615 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
616 #endif
617 ];
618 } rep;
619 struct ip_reply_arg arg;
620 struct net *net = dev_net(skb->dst->dev);
621
622 memset(&rep.th, 0, sizeof(struct tcphdr));
623 memset(&arg, 0, sizeof(arg));
624
625 arg.iov[0].iov_base = (unsigned char *)&rep;
626 arg.iov[0].iov_len = sizeof(rep.th);
627 if (ts) {
628 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
629 (TCPOPT_TIMESTAMP << 8) |
630 TCPOLEN_TIMESTAMP);
631 rep.opt[1] = htonl(tcp_time_stamp);
632 rep.opt[2] = htonl(ts);
633 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
634 }
635
636 /* Swap the send and the receive. */
637 rep.th.dest = th->source;
638 rep.th.source = th->dest;
639 rep.th.doff = arg.iov[0].iov_len / 4;
640 rep.th.seq = htonl(seq);
641 rep.th.ack_seq = htonl(ack);
642 rep.th.ack = 1;
643 rep.th.window = htons(win);
644
645 #ifdef CONFIG_TCP_MD5SIG
646 if (key) {
647 int offset = (ts) ? 3 : 0;
648
649 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
650 (TCPOPT_NOP << 16) |
651 (TCPOPT_MD5SIG << 8) |
652 TCPOLEN_MD5SIG);
653 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
654 rep.th.doff = arg.iov[0].iov_len/4;
655
656 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
657 key, ip_hdr(skb)->saddr,
658 ip_hdr(skb)->daddr, &rep.th);
659 }
660 #endif
661 arg.flags = reply_flags;
662 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
663 ip_hdr(skb)->saddr, /* XXX */
664 arg.iov[0].iov_len, IPPROTO_TCP, 0);
665 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
666 if (oif)
667 arg.bound_dev_if = oif;
668
669 ip_send_reply(net->ipv4.tcp_sock, skb,
670 &arg, arg.iov[0].iov_len);
671
672 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
673 }
674
tcp_v4_timewait_ack(struct sock * sk,struct sk_buff * skb)675 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
676 {
677 struct inet_timewait_sock *tw = inet_twsk(sk);
678 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
679
680 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
681 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
682 tcptw->tw_ts_recent,
683 tw->tw_bound_dev_if,
684 tcp_twsk_md5_key(tcptw),
685 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
686 );
687
688 inet_twsk_put(tw);
689 }
690
tcp_v4_reqsk_send_ack(struct sock * sk,struct sk_buff * skb,struct request_sock * req)691 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
692 struct request_sock *req)
693 {
694 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
695 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
696 req->ts_recent,
697 0,
698 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
699 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
700 }
701
702 /*
703 * Send a SYN-ACK after having received a SYN.
704 * This still operates on a request_sock only, not on a big
705 * socket.
706 */
__tcp_v4_send_synack(struct sock * sk,struct request_sock * req,struct dst_entry * dst)707 static int __tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
708 struct dst_entry *dst)
709 {
710 const struct inet_request_sock *ireq = inet_rsk(req);
711 int err = -1;
712 struct sk_buff * skb;
713
714 /* First, grab a route. */
715 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
716 return -1;
717
718 skb = tcp_make_synack(sk, dst, req);
719
720 if (skb) {
721 struct tcphdr *th = tcp_hdr(skb);
722
723 th->check = tcp_v4_check(skb->len,
724 ireq->loc_addr,
725 ireq->rmt_addr,
726 csum_partial(th, skb->len,
727 skb->csum));
728
729 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
730 ireq->rmt_addr,
731 ireq->opt);
732 err = net_xmit_eval(err);
733 }
734
735 dst_release(dst);
736 return err;
737 }
738
tcp_v4_send_synack(struct sock * sk,struct request_sock * req)739 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req)
740 {
741 return __tcp_v4_send_synack(sk, req, NULL);
742 }
743
744 /*
745 * IPv4 request_sock destructor.
746 */
tcp_v4_reqsk_destructor(struct request_sock * req)747 static void tcp_v4_reqsk_destructor(struct request_sock *req)
748 {
749 kfree(inet_rsk(req)->opt);
750 }
751
752 #ifdef CONFIG_SYN_COOKIES
syn_flood_warning(struct sk_buff * skb)753 static void syn_flood_warning(struct sk_buff *skb)
754 {
755 static unsigned long warntime;
756
757 if (time_after(jiffies, (warntime + HZ * 60))) {
758 warntime = jiffies;
759 printk(KERN_INFO
760 "possible SYN flooding on port %d. Sending cookies.\n",
761 ntohs(tcp_hdr(skb)->dest));
762 }
763 }
764 #endif
765
766 /*
767 * Save and compile IPv4 options into the request_sock if needed.
768 */
tcp_v4_save_options(struct sock * sk,struct sk_buff * skb)769 static struct ip_options *tcp_v4_save_options(struct sock *sk,
770 struct sk_buff *skb)
771 {
772 struct ip_options *opt = &(IPCB(skb)->opt);
773 struct ip_options *dopt = NULL;
774
775 if (opt && opt->optlen) {
776 int opt_size = optlength(opt);
777 dopt = kmalloc(opt_size, GFP_ATOMIC);
778 if (dopt) {
779 if (ip_options_echo(dopt, skb)) {
780 kfree(dopt);
781 dopt = NULL;
782 }
783 }
784 }
785 return dopt;
786 }
787
788 #ifdef CONFIG_TCP_MD5SIG
789 /*
790 * RFC2385 MD5 checksumming requires a mapping of
791 * IP address->MD5 Key.
792 * We need to maintain these in the sk structure.
793 */
794
795 /* Find the Key structure for an address. */
796 static struct tcp_md5sig_key *
tcp_v4_md5_do_lookup(struct sock * sk,__be32 addr)797 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
798 {
799 struct tcp_sock *tp = tcp_sk(sk);
800 int i;
801
802 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
803 return NULL;
804 for (i = 0; i < tp->md5sig_info->entries4; i++) {
805 if (tp->md5sig_info->keys4[i].addr == addr)
806 return &tp->md5sig_info->keys4[i].base;
807 }
808 return NULL;
809 }
810
tcp_v4_md5_lookup(struct sock * sk,struct sock * addr_sk)811 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
812 struct sock *addr_sk)
813 {
814 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
815 }
816
817 EXPORT_SYMBOL(tcp_v4_md5_lookup);
818
tcp_v4_reqsk_md5_lookup(struct sock * sk,struct request_sock * req)819 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
820 struct request_sock *req)
821 {
822 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
823 }
824
825 /* This can be called on a newly created socket, from other files */
tcp_v4_md5_do_add(struct sock * sk,__be32 addr,u8 * newkey,u8 newkeylen)826 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
827 u8 *newkey, u8 newkeylen)
828 {
829 /* Add Key to the list */
830 struct tcp_md5sig_key *key;
831 struct tcp_sock *tp = tcp_sk(sk);
832 struct tcp4_md5sig_key *keys;
833
834 key = tcp_v4_md5_do_lookup(sk, addr);
835 if (key) {
836 /* Pre-existing entry - just update that one. */
837 kfree(key->key);
838 key->key = newkey;
839 key->keylen = newkeylen;
840 } else {
841 struct tcp_md5sig_info *md5sig;
842
843 if (!tp->md5sig_info) {
844 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
845 GFP_ATOMIC);
846 if (!tp->md5sig_info) {
847 kfree(newkey);
848 return -ENOMEM;
849 }
850 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
851 }
852 if (tcp_alloc_md5sig_pool() == NULL) {
853 kfree(newkey);
854 return -ENOMEM;
855 }
856 md5sig = tp->md5sig_info;
857
858 if (md5sig->alloced4 == md5sig->entries4) {
859 keys = kmalloc((sizeof(*keys) *
860 (md5sig->entries4 + 1)), GFP_ATOMIC);
861 if (!keys) {
862 kfree(newkey);
863 tcp_free_md5sig_pool();
864 return -ENOMEM;
865 }
866
867 if (md5sig->entries4)
868 memcpy(keys, md5sig->keys4,
869 sizeof(*keys) * md5sig->entries4);
870
871 /* Free old key list, and reference new one */
872 kfree(md5sig->keys4);
873 md5sig->keys4 = keys;
874 md5sig->alloced4++;
875 }
876 md5sig->entries4++;
877 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
878 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
879 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
880 }
881 return 0;
882 }
883
884 EXPORT_SYMBOL(tcp_v4_md5_do_add);
885
tcp_v4_md5_add_func(struct sock * sk,struct sock * addr_sk,u8 * newkey,u8 newkeylen)886 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
887 u8 *newkey, u8 newkeylen)
888 {
889 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
890 newkey, newkeylen);
891 }
892
tcp_v4_md5_do_del(struct sock * sk,__be32 addr)893 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
894 {
895 struct tcp_sock *tp = tcp_sk(sk);
896 int i;
897
898 for (i = 0; i < tp->md5sig_info->entries4; i++) {
899 if (tp->md5sig_info->keys4[i].addr == addr) {
900 /* Free the key */
901 kfree(tp->md5sig_info->keys4[i].base.key);
902 tp->md5sig_info->entries4--;
903
904 if (tp->md5sig_info->entries4 == 0) {
905 kfree(tp->md5sig_info->keys4);
906 tp->md5sig_info->keys4 = NULL;
907 tp->md5sig_info->alloced4 = 0;
908 } else if (tp->md5sig_info->entries4 != i) {
909 /* Need to do some manipulation */
910 memmove(&tp->md5sig_info->keys4[i],
911 &tp->md5sig_info->keys4[i+1],
912 (tp->md5sig_info->entries4 - i) *
913 sizeof(struct tcp4_md5sig_key));
914 }
915 tcp_free_md5sig_pool();
916 return 0;
917 }
918 }
919 return -ENOENT;
920 }
921
922 EXPORT_SYMBOL(tcp_v4_md5_do_del);
923
tcp_v4_clear_md5_list(struct sock * sk)924 static void tcp_v4_clear_md5_list(struct sock *sk)
925 {
926 struct tcp_sock *tp = tcp_sk(sk);
927
928 /* Free each key, then the set of key keys,
929 * the crypto element, and then decrement our
930 * hold on the last resort crypto.
931 */
932 if (tp->md5sig_info->entries4) {
933 int i;
934 for (i = 0; i < tp->md5sig_info->entries4; i++)
935 kfree(tp->md5sig_info->keys4[i].base.key);
936 tp->md5sig_info->entries4 = 0;
937 tcp_free_md5sig_pool();
938 }
939 if (tp->md5sig_info->keys4) {
940 kfree(tp->md5sig_info->keys4);
941 tp->md5sig_info->keys4 = NULL;
942 tp->md5sig_info->alloced4 = 0;
943 }
944 }
945
tcp_v4_parse_md5_keys(struct sock * sk,char __user * optval,int optlen)946 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
947 int optlen)
948 {
949 struct tcp_md5sig cmd;
950 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
951 u8 *newkey;
952
953 if (optlen < sizeof(cmd))
954 return -EINVAL;
955
956 if (copy_from_user(&cmd, optval, sizeof(cmd)))
957 return -EFAULT;
958
959 if (sin->sin_family != AF_INET)
960 return -EINVAL;
961
962 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
963 if (!tcp_sk(sk)->md5sig_info)
964 return -ENOENT;
965 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
966 }
967
968 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
969 return -EINVAL;
970
971 if (!tcp_sk(sk)->md5sig_info) {
972 struct tcp_sock *tp = tcp_sk(sk);
973 struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
974
975 if (!p)
976 return -EINVAL;
977
978 tp->md5sig_info = p;
979 sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
980 }
981
982 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
983 if (!newkey)
984 return -ENOMEM;
985 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
986 newkey, cmd.tcpm_keylen);
987 }
988
tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool * hp,__be32 daddr,__be32 saddr,int nbytes)989 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
990 __be32 daddr, __be32 saddr, int nbytes)
991 {
992 struct tcp4_pseudohdr *bp;
993 struct scatterlist sg;
994
995 bp = &hp->md5_blk.ip4;
996
997 /*
998 * 1. the TCP pseudo-header (in the order: source IP address,
999 * destination IP address, zero-padded protocol number, and
1000 * segment length)
1001 */
1002 bp->saddr = saddr;
1003 bp->daddr = daddr;
1004 bp->pad = 0;
1005 bp->protocol = IPPROTO_TCP;
1006 bp->len = cpu_to_be16(nbytes);
1007
1008 sg_init_one(&sg, bp, sizeof(*bp));
1009 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1010 }
1011
tcp_v4_md5_hash_hdr(char * md5_hash,struct tcp_md5sig_key * key,__be32 daddr,__be32 saddr,struct tcphdr * th)1012 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1013 __be32 daddr, __be32 saddr, struct tcphdr *th)
1014 {
1015 struct tcp_md5sig_pool *hp;
1016 struct hash_desc *desc;
1017
1018 hp = tcp_get_md5sig_pool();
1019 if (!hp)
1020 goto clear_hash_noput;
1021 desc = &hp->md5_desc;
1022
1023 if (crypto_hash_init(desc))
1024 goto clear_hash;
1025 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1026 goto clear_hash;
1027 if (tcp_md5_hash_header(hp, th))
1028 goto clear_hash;
1029 if (tcp_md5_hash_key(hp, key))
1030 goto clear_hash;
1031 if (crypto_hash_final(desc, md5_hash))
1032 goto clear_hash;
1033
1034 tcp_put_md5sig_pool();
1035 return 0;
1036
1037 clear_hash:
1038 tcp_put_md5sig_pool();
1039 clear_hash_noput:
1040 memset(md5_hash, 0, 16);
1041 return 1;
1042 }
1043
tcp_v4_md5_hash_skb(char * md5_hash,struct tcp_md5sig_key * key,struct sock * sk,struct request_sock * req,struct sk_buff * skb)1044 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1045 struct sock *sk, struct request_sock *req,
1046 struct sk_buff *skb)
1047 {
1048 struct tcp_md5sig_pool *hp;
1049 struct hash_desc *desc;
1050 struct tcphdr *th = tcp_hdr(skb);
1051 __be32 saddr, daddr;
1052
1053 if (sk) {
1054 saddr = inet_sk(sk)->saddr;
1055 daddr = inet_sk(sk)->daddr;
1056 } else if (req) {
1057 saddr = inet_rsk(req)->loc_addr;
1058 daddr = inet_rsk(req)->rmt_addr;
1059 } else {
1060 const struct iphdr *iph = ip_hdr(skb);
1061 saddr = iph->saddr;
1062 daddr = iph->daddr;
1063 }
1064
1065 hp = tcp_get_md5sig_pool();
1066 if (!hp)
1067 goto clear_hash_noput;
1068 desc = &hp->md5_desc;
1069
1070 if (crypto_hash_init(desc))
1071 goto clear_hash;
1072
1073 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1074 goto clear_hash;
1075 if (tcp_md5_hash_header(hp, th))
1076 goto clear_hash;
1077 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1078 goto clear_hash;
1079 if (tcp_md5_hash_key(hp, key))
1080 goto clear_hash;
1081 if (crypto_hash_final(desc, md5_hash))
1082 goto clear_hash;
1083
1084 tcp_put_md5sig_pool();
1085 return 0;
1086
1087 clear_hash:
1088 tcp_put_md5sig_pool();
1089 clear_hash_noput:
1090 memset(md5_hash, 0, 16);
1091 return 1;
1092 }
1093
1094 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1095
tcp_v4_inbound_md5_hash(struct sock * sk,struct sk_buff * skb)1096 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1097 {
1098 /*
1099 * This gets called for each TCP segment that arrives
1100 * so we want to be efficient.
1101 * We have 3 drop cases:
1102 * o No MD5 hash and one expected.
1103 * o MD5 hash and we're not expecting one.
1104 * o MD5 hash and its wrong.
1105 */
1106 __u8 *hash_location = NULL;
1107 struct tcp_md5sig_key *hash_expected;
1108 const struct iphdr *iph = ip_hdr(skb);
1109 struct tcphdr *th = tcp_hdr(skb);
1110 int genhash;
1111 unsigned char newhash[16];
1112
1113 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1114 hash_location = tcp_parse_md5sig_option(th);
1115
1116 /* We've parsed the options - do we have a hash? */
1117 if (!hash_expected && !hash_location)
1118 return 0;
1119
1120 if (hash_expected && !hash_location) {
1121 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1122 return 1;
1123 }
1124
1125 if (!hash_expected && hash_location) {
1126 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1127 return 1;
1128 }
1129
1130 /* Okay, so this is hash_expected and hash_location -
1131 * so we need to calculate the checksum.
1132 */
1133 genhash = tcp_v4_md5_hash_skb(newhash,
1134 hash_expected,
1135 NULL, NULL, skb);
1136
1137 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1138 if (net_ratelimit()) {
1139 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1140 &iph->saddr, ntohs(th->source),
1141 &iph->daddr, ntohs(th->dest),
1142 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1143 }
1144 return 1;
1145 }
1146 return 0;
1147 }
1148
1149 #endif
1150
1151 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1152 .family = PF_INET,
1153 .obj_size = sizeof(struct tcp_request_sock),
1154 .rtx_syn_ack = tcp_v4_send_synack,
1155 .send_ack = tcp_v4_reqsk_send_ack,
1156 .destructor = tcp_v4_reqsk_destructor,
1157 .send_reset = tcp_v4_send_reset,
1158 };
1159
1160 #ifdef CONFIG_TCP_MD5SIG
1161 static struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1162 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1163 };
1164 #endif
1165
1166 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1167 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1168 .twsk_unique = tcp_twsk_unique,
1169 .twsk_destructor= tcp_twsk_destructor,
1170 };
1171
tcp_v4_conn_request(struct sock * sk,struct sk_buff * skb)1172 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1173 {
1174 struct inet_request_sock *ireq;
1175 struct tcp_options_received tmp_opt;
1176 struct request_sock *req;
1177 __be32 saddr = ip_hdr(skb)->saddr;
1178 __be32 daddr = ip_hdr(skb)->daddr;
1179 __u32 isn = TCP_SKB_CB(skb)->when;
1180 struct dst_entry *dst = NULL;
1181 #ifdef CONFIG_SYN_COOKIES
1182 int want_cookie = 0;
1183 #else
1184 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1185 #endif
1186
1187 /* Never answer to SYNs send to broadcast or multicast */
1188 if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1189 goto drop;
1190
1191 /* TW buckets are converted to open requests without
1192 * limitations, they conserve resources and peer is
1193 * evidently real one.
1194 */
1195 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1196 #ifdef CONFIG_SYN_COOKIES
1197 if (sysctl_tcp_syncookies) {
1198 want_cookie = 1;
1199 } else
1200 #endif
1201 goto drop;
1202 }
1203
1204 /* Accept backlog is full. If we have already queued enough
1205 * of warm entries in syn queue, drop request. It is better than
1206 * clogging syn queue with openreqs with exponentially increasing
1207 * timeout.
1208 */
1209 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1210 goto drop;
1211
1212 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1213 if (!req)
1214 goto drop;
1215
1216 #ifdef CONFIG_TCP_MD5SIG
1217 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1218 #endif
1219
1220 tcp_clear_options(&tmp_opt);
1221 tmp_opt.mss_clamp = 536;
1222 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1223
1224 tcp_parse_options(skb, &tmp_opt, 0);
1225
1226 if (want_cookie && !tmp_opt.saw_tstamp)
1227 tcp_clear_options(&tmp_opt);
1228
1229 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1230 /* Some OSes (unknown ones, but I see them on web server, which
1231 * contains information interesting only for windows'
1232 * users) do not send their stamp in SYN. It is easy case.
1233 * We simply do not advertise TS support.
1234 */
1235 tmp_opt.saw_tstamp = 0;
1236 tmp_opt.tstamp_ok = 0;
1237 }
1238 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1239
1240 tcp_openreq_init(req, &tmp_opt, skb);
1241
1242 if (security_inet_conn_request(sk, skb, req))
1243 goto drop_and_free;
1244
1245 ireq = inet_rsk(req);
1246 ireq->loc_addr = daddr;
1247 ireq->rmt_addr = saddr;
1248 ireq->no_srccheck = inet_sk(sk)->transparent;
1249 ireq->opt = tcp_v4_save_options(sk, skb);
1250 if (!want_cookie)
1251 TCP_ECN_create_request(req, tcp_hdr(skb));
1252
1253 if (want_cookie) {
1254 #ifdef CONFIG_SYN_COOKIES
1255 syn_flood_warning(skb);
1256 req->cookie_ts = tmp_opt.tstamp_ok;
1257 #endif
1258 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1259 } else if (!isn) {
1260 struct inet_peer *peer = NULL;
1261
1262 /* VJ's idea. We save last timestamp seen
1263 * from the destination in peer table, when entering
1264 * state TIME-WAIT, and check against it before
1265 * accepting new connection request.
1266 *
1267 * If "isn" is not zero, this request hit alive
1268 * timewait bucket, so that all the necessary checks
1269 * are made in the function processing timewait state.
1270 */
1271 if (tmp_opt.saw_tstamp &&
1272 tcp_death_row.sysctl_tw_recycle &&
1273 (dst = inet_csk_route_req(sk, req)) != NULL &&
1274 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1275 peer->v4daddr == saddr) {
1276 if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1277 (s32)(peer->tcp_ts - req->ts_recent) >
1278 TCP_PAWS_WINDOW) {
1279 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1280 goto drop_and_release;
1281 }
1282 }
1283 /* Kill the following clause, if you dislike this way. */
1284 else if (!sysctl_tcp_syncookies &&
1285 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1286 (sysctl_max_syn_backlog >> 2)) &&
1287 (!peer || !peer->tcp_ts_stamp) &&
1288 (!dst || !dst_metric(dst, RTAX_RTT))) {
1289 /* Without syncookies last quarter of
1290 * backlog is filled with destinations,
1291 * proven to be alive.
1292 * It means that we continue to communicate
1293 * to destinations, already remembered
1294 * to the moment of synflood.
1295 */
1296 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1297 &saddr, ntohs(tcp_hdr(skb)->source));
1298 goto drop_and_release;
1299 }
1300
1301 isn = tcp_v4_init_sequence(skb);
1302 }
1303 tcp_rsk(req)->snt_isn = isn;
1304
1305 if (__tcp_v4_send_synack(sk, req, dst) || want_cookie)
1306 goto drop_and_free;
1307
1308 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1309 return 0;
1310
1311 drop_and_release:
1312 dst_release(dst);
1313 drop_and_free:
1314 reqsk_free(req);
1315 drop:
1316 return 0;
1317 }
1318
1319
1320 /*
1321 * The three way handshake has completed - we got a valid synack -
1322 * now create the new socket.
1323 */
tcp_v4_syn_recv_sock(struct sock * sk,struct sk_buff * skb,struct request_sock * req,struct dst_entry * dst)1324 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1325 struct request_sock *req,
1326 struct dst_entry *dst)
1327 {
1328 struct inet_request_sock *ireq;
1329 struct inet_sock *newinet;
1330 struct tcp_sock *newtp;
1331 struct sock *newsk;
1332 #ifdef CONFIG_TCP_MD5SIG
1333 struct tcp_md5sig_key *key;
1334 #endif
1335
1336 if (sk_acceptq_is_full(sk))
1337 goto exit_overflow;
1338
1339 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
1340 goto exit;
1341
1342 newsk = tcp_create_openreq_child(sk, req, skb);
1343 if (!newsk)
1344 goto exit;
1345
1346 newsk->sk_gso_type = SKB_GSO_TCPV4;
1347 sk_setup_caps(newsk, dst);
1348
1349 newtp = tcp_sk(newsk);
1350 newinet = inet_sk(newsk);
1351 ireq = inet_rsk(req);
1352 newinet->daddr = ireq->rmt_addr;
1353 newinet->rcv_saddr = ireq->loc_addr;
1354 newinet->saddr = ireq->loc_addr;
1355 newinet->opt = ireq->opt;
1356 ireq->opt = NULL;
1357 newinet->mc_index = inet_iif(skb);
1358 newinet->mc_ttl = ip_hdr(skb)->ttl;
1359 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1360 if (newinet->opt)
1361 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
1362 newinet->id = newtp->write_seq ^ jiffies;
1363
1364 tcp_mtup_init(newsk);
1365 tcp_sync_mss(newsk, dst_mtu(dst));
1366 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1367 if (tcp_sk(sk)->rx_opt.user_mss &&
1368 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1369 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1370
1371 tcp_initialize_rcv_mss(newsk);
1372
1373 #ifdef CONFIG_TCP_MD5SIG
1374 /* Copy over the MD5 key from the original socket */
1375 if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
1376 /*
1377 * We're using one, so create a matching key
1378 * on the newsk structure. If we fail to get
1379 * memory, then we end up not copying the key
1380 * across. Shucks.
1381 */
1382 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1383 if (newkey != NULL)
1384 tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
1385 newkey, key->keylen);
1386 newsk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1387 }
1388 #endif
1389
1390 __inet_hash_nolisten(newsk);
1391 __inet_inherit_port(sk, newsk);
1392
1393 return newsk;
1394
1395 exit_overflow:
1396 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1397 exit:
1398 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1399 dst_release(dst);
1400 return NULL;
1401 }
1402
tcp_v4_hnd_req(struct sock * sk,struct sk_buff * skb)1403 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1404 {
1405 struct tcphdr *th = tcp_hdr(skb);
1406 const struct iphdr *iph = ip_hdr(skb);
1407 struct sock *nsk;
1408 struct request_sock **prev;
1409 /* Find possible connection requests. */
1410 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1411 iph->saddr, iph->daddr);
1412 if (req)
1413 return tcp_check_req(sk, skb, req, prev);
1414
1415 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1416 th->source, iph->daddr, th->dest, inet_iif(skb));
1417
1418 if (nsk) {
1419 if (nsk->sk_state != TCP_TIME_WAIT) {
1420 bh_lock_sock(nsk);
1421 return nsk;
1422 }
1423 inet_twsk_put(inet_twsk(nsk));
1424 return NULL;
1425 }
1426
1427 #ifdef CONFIG_SYN_COOKIES
1428 if (!th->rst && !th->syn && th->ack)
1429 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1430 #endif
1431 return sk;
1432 }
1433
tcp_v4_checksum_init(struct sk_buff * skb)1434 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1435 {
1436 const struct iphdr *iph = ip_hdr(skb);
1437
1438 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1439 if (!tcp_v4_check(skb->len, iph->saddr,
1440 iph->daddr, skb->csum)) {
1441 skb->ip_summed = CHECKSUM_UNNECESSARY;
1442 return 0;
1443 }
1444 }
1445
1446 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1447 skb->len, IPPROTO_TCP, 0);
1448
1449 if (skb->len <= 76) {
1450 return __skb_checksum_complete(skb);
1451 }
1452 return 0;
1453 }
1454
1455
1456 /* The socket must have it's spinlock held when we get
1457 * here.
1458 *
1459 * We have a potential double-lock case here, so even when
1460 * doing backlog processing we use the BH locking scheme.
1461 * This is because we cannot sleep with the original spinlock
1462 * held.
1463 */
tcp_v4_do_rcv(struct sock * sk,struct sk_buff * skb)1464 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1465 {
1466 struct sock *rsk;
1467 #ifdef CONFIG_TCP_MD5SIG
1468 /*
1469 * We really want to reject the packet as early as possible
1470 * if:
1471 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1472 * o There is an MD5 option and we're not expecting one
1473 */
1474 if (tcp_v4_inbound_md5_hash(sk, skb))
1475 goto discard;
1476 #endif
1477
1478 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1479 TCP_CHECK_TIMER(sk);
1480 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1481 rsk = sk;
1482 goto reset;
1483 }
1484 TCP_CHECK_TIMER(sk);
1485 return 0;
1486 }
1487
1488 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1489 goto csum_err;
1490
1491 if (sk->sk_state == TCP_LISTEN) {
1492 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1493 if (!nsk)
1494 goto discard;
1495
1496 if (nsk != sk) {
1497 if (tcp_child_process(sk, nsk, skb)) {
1498 rsk = nsk;
1499 goto reset;
1500 }
1501 return 0;
1502 }
1503 }
1504
1505 TCP_CHECK_TIMER(sk);
1506 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1507 rsk = sk;
1508 goto reset;
1509 }
1510 TCP_CHECK_TIMER(sk);
1511 return 0;
1512
1513 reset:
1514 tcp_v4_send_reset(rsk, skb);
1515 discard:
1516 kfree_skb(skb);
1517 /* Be careful here. If this function gets more complicated and
1518 * gcc suffers from register pressure on the x86, sk (in %ebx)
1519 * might be destroyed here. This current version compiles correctly,
1520 * but you have been warned.
1521 */
1522 return 0;
1523
1524 csum_err:
1525 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1526 goto discard;
1527 }
1528
1529 /*
1530 * From tcp_input.c
1531 */
1532
tcp_v4_rcv(struct sk_buff * skb)1533 int tcp_v4_rcv(struct sk_buff *skb)
1534 {
1535 const struct iphdr *iph;
1536 struct tcphdr *th;
1537 struct sock *sk;
1538 int ret;
1539 struct net *net = dev_net(skb->dev);
1540
1541 if (skb->pkt_type != PACKET_HOST)
1542 goto discard_it;
1543
1544 /* Count it even if it's bad */
1545 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1546
1547 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1548 goto discard_it;
1549
1550 th = tcp_hdr(skb);
1551
1552 if (th->doff < sizeof(struct tcphdr) / 4)
1553 goto bad_packet;
1554 if (!pskb_may_pull(skb, th->doff * 4))
1555 goto discard_it;
1556
1557 /* An explanation is required here, I think.
1558 * Packet length and doff are validated by header prediction,
1559 * provided case of th->doff==0 is eliminated.
1560 * So, we defer the checks. */
1561 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1562 goto bad_packet;
1563
1564 th = tcp_hdr(skb);
1565 iph = ip_hdr(skb);
1566 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1567 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1568 skb->len - th->doff * 4);
1569 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1570 TCP_SKB_CB(skb)->when = 0;
1571 TCP_SKB_CB(skb)->flags = iph->tos;
1572 TCP_SKB_CB(skb)->sacked = 0;
1573
1574 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1575 if (!sk)
1576 goto no_tcp_socket;
1577
1578 process:
1579 if (sk->sk_state == TCP_TIME_WAIT)
1580 goto do_time_wait;
1581
1582 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1583 goto discard_and_relse;
1584 nf_reset(skb);
1585
1586 if (sk_filter(sk, skb))
1587 goto discard_and_relse;
1588
1589 skb->dev = NULL;
1590
1591 bh_lock_sock_nested(sk);
1592 ret = 0;
1593 if (!sock_owned_by_user(sk)) {
1594 #ifdef CONFIG_NET_DMA
1595 struct tcp_sock *tp = tcp_sk(sk);
1596 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1597 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1598 if (tp->ucopy.dma_chan)
1599 ret = tcp_v4_do_rcv(sk, skb);
1600 else
1601 #endif
1602 {
1603 if (!tcp_prequeue(sk, skb))
1604 ret = tcp_v4_do_rcv(sk, skb);
1605 }
1606 } else
1607 sk_add_backlog(sk, skb);
1608 bh_unlock_sock(sk);
1609
1610 sock_put(sk);
1611
1612 return ret;
1613
1614 no_tcp_socket:
1615 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1616 goto discard_it;
1617
1618 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1619 bad_packet:
1620 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1621 } else {
1622 tcp_v4_send_reset(NULL, skb);
1623 }
1624
1625 discard_it:
1626 /* Discard frame. */
1627 kfree_skb(skb);
1628 return 0;
1629
1630 discard_and_relse:
1631 sock_put(sk);
1632 goto discard_it;
1633
1634 do_time_wait:
1635 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1636 inet_twsk_put(inet_twsk(sk));
1637 goto discard_it;
1638 }
1639
1640 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1641 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1642 inet_twsk_put(inet_twsk(sk));
1643 goto discard_it;
1644 }
1645 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1646 case TCP_TW_SYN: {
1647 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1648 &tcp_hashinfo,
1649 iph->daddr, th->dest,
1650 inet_iif(skb));
1651 if (sk2) {
1652 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1653 inet_twsk_put(inet_twsk(sk));
1654 sk = sk2;
1655 goto process;
1656 }
1657 /* Fall through to ACK */
1658 }
1659 case TCP_TW_ACK:
1660 tcp_v4_timewait_ack(sk, skb);
1661 break;
1662 case TCP_TW_RST:
1663 goto no_tcp_socket;
1664 case TCP_TW_SUCCESS:;
1665 }
1666 goto discard_it;
1667 }
1668
1669 /* VJ's idea. Save last timestamp seen from this destination
1670 * and hold it at least for normal timewait interval to use for duplicate
1671 * segment detection in subsequent connections, before they enter synchronized
1672 * state.
1673 */
1674
tcp_v4_remember_stamp(struct sock * sk)1675 int tcp_v4_remember_stamp(struct sock *sk)
1676 {
1677 struct inet_sock *inet = inet_sk(sk);
1678 struct tcp_sock *tp = tcp_sk(sk);
1679 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1680 struct inet_peer *peer = NULL;
1681 int release_it = 0;
1682
1683 if (!rt || rt->rt_dst != inet->daddr) {
1684 peer = inet_getpeer(inet->daddr, 1);
1685 release_it = 1;
1686 } else {
1687 if (!rt->peer)
1688 rt_bind_peer(rt, 1);
1689 peer = rt->peer;
1690 }
1691
1692 if (peer) {
1693 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1694 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1695 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1696 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1697 peer->tcp_ts = tp->rx_opt.ts_recent;
1698 }
1699 if (release_it)
1700 inet_putpeer(peer);
1701 return 1;
1702 }
1703
1704 return 0;
1705 }
1706
tcp_v4_tw_remember_stamp(struct inet_timewait_sock * tw)1707 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1708 {
1709 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1710
1711 if (peer) {
1712 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1713
1714 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1715 (peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
1716 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1717 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1718 peer->tcp_ts = tcptw->tw_ts_recent;
1719 }
1720 inet_putpeer(peer);
1721 return 1;
1722 }
1723
1724 return 0;
1725 }
1726
1727 struct inet_connection_sock_af_ops ipv4_specific = {
1728 .queue_xmit = ip_queue_xmit,
1729 .send_check = tcp_v4_send_check,
1730 .rebuild_header = inet_sk_rebuild_header,
1731 .conn_request = tcp_v4_conn_request,
1732 .syn_recv_sock = tcp_v4_syn_recv_sock,
1733 .remember_stamp = tcp_v4_remember_stamp,
1734 .net_header_len = sizeof(struct iphdr),
1735 .setsockopt = ip_setsockopt,
1736 .getsockopt = ip_getsockopt,
1737 .addr2sockaddr = inet_csk_addr2sockaddr,
1738 .sockaddr_len = sizeof(struct sockaddr_in),
1739 .bind_conflict = inet_csk_bind_conflict,
1740 #ifdef CONFIG_COMPAT
1741 .compat_setsockopt = compat_ip_setsockopt,
1742 .compat_getsockopt = compat_ip_getsockopt,
1743 #endif
1744 };
1745
1746 #ifdef CONFIG_TCP_MD5SIG
1747 static struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1748 .md5_lookup = tcp_v4_md5_lookup,
1749 .calc_md5_hash = tcp_v4_md5_hash_skb,
1750 .md5_add = tcp_v4_md5_add_func,
1751 .md5_parse = tcp_v4_parse_md5_keys,
1752 };
1753 #endif
1754
1755 /* NOTE: A lot of things set to zero explicitly by call to
1756 * sk_alloc() so need not be done here.
1757 */
tcp_v4_init_sock(struct sock * sk)1758 static int tcp_v4_init_sock(struct sock *sk)
1759 {
1760 struct inet_connection_sock *icsk = inet_csk(sk);
1761 struct tcp_sock *tp = tcp_sk(sk);
1762
1763 skb_queue_head_init(&tp->out_of_order_queue);
1764 tcp_init_xmit_timers(sk);
1765 tcp_prequeue_init(tp);
1766
1767 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1768 tp->mdev = TCP_TIMEOUT_INIT;
1769
1770 /* So many TCP implementations out there (incorrectly) count the
1771 * initial SYN frame in their delayed-ACK and congestion control
1772 * algorithms that we must have the following bandaid to talk
1773 * efficiently to them. -DaveM
1774 */
1775 tp->snd_cwnd = 2;
1776
1777 /* See draft-stevens-tcpca-spec-01 for discussion of the
1778 * initialization of these values.
1779 */
1780 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1781 tp->snd_cwnd_clamp = ~0;
1782 tp->mss_cache = 536;
1783
1784 tp->reordering = sysctl_tcp_reordering;
1785 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1786
1787 sk->sk_state = TCP_CLOSE;
1788
1789 sk->sk_write_space = sk_stream_write_space;
1790 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1791
1792 icsk->icsk_af_ops = &ipv4_specific;
1793 icsk->icsk_sync_mss = tcp_sync_mss;
1794 #ifdef CONFIG_TCP_MD5SIG
1795 tp->af_specific = &tcp_sock_ipv4_specific;
1796 #endif
1797
1798 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1799 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1800
1801 local_bh_disable();
1802 percpu_counter_inc(&tcp_sockets_allocated);
1803 local_bh_enable();
1804
1805 return 0;
1806 }
1807
tcp_v4_destroy_sock(struct sock * sk)1808 void tcp_v4_destroy_sock(struct sock *sk)
1809 {
1810 struct tcp_sock *tp = tcp_sk(sk);
1811
1812 tcp_clear_xmit_timers(sk);
1813
1814 tcp_cleanup_congestion_control(sk);
1815
1816 /* Cleanup up the write buffer. */
1817 tcp_write_queue_purge(sk);
1818
1819 /* Cleans up our, hopefully empty, out_of_order_queue. */
1820 __skb_queue_purge(&tp->out_of_order_queue);
1821
1822 #ifdef CONFIG_TCP_MD5SIG
1823 /* Clean up the MD5 key list, if any */
1824 if (tp->md5sig_info) {
1825 tcp_v4_clear_md5_list(sk);
1826 kfree(tp->md5sig_info);
1827 tp->md5sig_info = NULL;
1828 }
1829 #endif
1830
1831 #ifdef CONFIG_NET_DMA
1832 /* Cleans up our sk_async_wait_queue */
1833 __skb_queue_purge(&sk->sk_async_wait_queue);
1834 #endif
1835
1836 /* Clean prequeue, it must be empty really */
1837 __skb_queue_purge(&tp->ucopy.prequeue);
1838
1839 /* Clean up a referenced TCP bind bucket. */
1840 if (inet_csk(sk)->icsk_bind_hash)
1841 inet_put_port(sk);
1842
1843 /*
1844 * If sendmsg cached page exists, toss it.
1845 */
1846 if (sk->sk_sndmsg_page) {
1847 __free_page(sk->sk_sndmsg_page);
1848 sk->sk_sndmsg_page = NULL;
1849 }
1850
1851 percpu_counter_dec(&tcp_sockets_allocated);
1852 }
1853
1854 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1855
1856 /*
1857 * tcp_v4_nuke_addr - destroy all sockets on the given local address
1858 */
tcp_v4_nuke_addr(__u32 saddr)1859 void tcp_v4_nuke_addr(__u32 saddr)
1860 {
1861 unsigned int bucket;
1862
1863 for (bucket = 0; bucket < tcp_hashinfo.ehash_size; bucket++) {
1864 struct hlist_nulls_node *node;
1865 struct sock *sk;
1866 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, bucket);
1867
1868 restart:
1869 spin_lock_bh(lock);
1870 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[bucket].chain) {
1871 struct inet_sock *inet = inet_sk(sk);
1872
1873 if (inet->rcv_saddr != saddr)
1874 continue;
1875 if (sysctl_ip_dynaddr && sk->sk_state == TCP_SYN_SENT)
1876 continue;
1877 if (sock_flag(sk, SOCK_DEAD))
1878 continue;
1879
1880 sock_hold(sk);
1881 spin_unlock_bh(lock);
1882
1883 local_bh_disable();
1884 bh_lock_sock(sk);
1885 sk->sk_err = ETIMEDOUT;
1886 sk->sk_error_report(sk);
1887
1888 tcp_done(sk);
1889 bh_unlock_sock(sk);
1890 local_bh_enable();
1891 sock_put(sk);
1892
1893 goto restart;
1894 }
1895 spin_unlock_bh(lock);
1896 }
1897 }
1898
1899 #ifdef CONFIG_PROC_FS
1900 /* Proc filesystem TCP sock list dumping. */
1901
tw_head(struct hlist_nulls_head * head)1902 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1903 {
1904 return hlist_nulls_empty(head) ? NULL :
1905 list_entry(head->first, struct inet_timewait_sock, tw_node);
1906 }
1907
tw_next(struct inet_timewait_sock * tw)1908 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1909 {
1910 return !is_a_nulls(tw->tw_node.next) ?
1911 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1912 }
1913
listening_get_next(struct seq_file * seq,void * cur)1914 static void *listening_get_next(struct seq_file *seq, void *cur)
1915 {
1916 struct inet_connection_sock *icsk;
1917 struct hlist_nulls_node *node;
1918 struct sock *sk = cur;
1919 struct inet_listen_hashbucket *ilb;
1920 struct tcp_iter_state *st = seq->private;
1921 struct net *net = seq_file_net(seq);
1922
1923 if (!sk) {
1924 st->bucket = 0;
1925 ilb = &tcp_hashinfo.listening_hash[0];
1926 spin_lock_bh(&ilb->lock);
1927 sk = sk_nulls_head(&ilb->head);
1928 goto get_sk;
1929 }
1930 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1931 ++st->num;
1932
1933 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1934 struct request_sock *req = cur;
1935
1936 icsk = inet_csk(st->syn_wait_sk);
1937 req = req->dl_next;
1938 while (1) {
1939 while (req) {
1940 if (req->rsk_ops->family == st->family) {
1941 cur = req;
1942 goto out;
1943 }
1944 req = req->dl_next;
1945 }
1946 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1947 break;
1948 get_req:
1949 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1950 }
1951 sk = sk_next(st->syn_wait_sk);
1952 st->state = TCP_SEQ_STATE_LISTENING;
1953 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1954 } else {
1955 icsk = inet_csk(sk);
1956 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1957 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1958 goto start_req;
1959 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1960 sk = sk_next(sk);
1961 }
1962 get_sk:
1963 sk_nulls_for_each_from(sk, node) {
1964 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
1965 cur = sk;
1966 goto out;
1967 }
1968 icsk = inet_csk(sk);
1969 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1970 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1971 start_req:
1972 st->uid = sock_i_uid(sk);
1973 st->syn_wait_sk = sk;
1974 st->state = TCP_SEQ_STATE_OPENREQ;
1975 st->sbucket = 0;
1976 goto get_req;
1977 }
1978 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1979 }
1980 spin_unlock_bh(&ilb->lock);
1981 if (++st->bucket < INET_LHTABLE_SIZE) {
1982 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1983 spin_lock_bh(&ilb->lock);
1984 sk = sk_nulls_head(&ilb->head);
1985 goto get_sk;
1986 }
1987 cur = NULL;
1988 out:
1989 return cur;
1990 }
1991
listening_get_idx(struct seq_file * seq,loff_t * pos)1992 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1993 {
1994 void *rc = listening_get_next(seq, NULL);
1995
1996 while (rc && *pos) {
1997 rc = listening_get_next(seq, rc);
1998 --*pos;
1999 }
2000 return rc;
2001 }
2002
empty_bucket(struct tcp_iter_state * st)2003 static inline int empty_bucket(struct tcp_iter_state *st)
2004 {
2005 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2006 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2007 }
2008
established_get_first(struct seq_file * seq)2009 static void *established_get_first(struct seq_file *seq)
2010 {
2011 struct tcp_iter_state *st = seq->private;
2012 struct net *net = seq_file_net(seq);
2013 void *rc = NULL;
2014
2015 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
2016 struct sock *sk;
2017 struct hlist_nulls_node *node;
2018 struct inet_timewait_sock *tw;
2019 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2020
2021 /* Lockless fast path for the common case of empty buckets */
2022 if (empty_bucket(st))
2023 continue;
2024
2025 spin_lock_bh(lock);
2026 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2027 if (sk->sk_family != st->family ||
2028 !net_eq(sock_net(sk), net)) {
2029 continue;
2030 }
2031 rc = sk;
2032 goto out;
2033 }
2034 st->state = TCP_SEQ_STATE_TIME_WAIT;
2035 inet_twsk_for_each(tw, node,
2036 &tcp_hashinfo.ehash[st->bucket].twchain) {
2037 if (tw->tw_family != st->family ||
2038 !net_eq(twsk_net(tw), net)) {
2039 continue;
2040 }
2041 rc = tw;
2042 goto out;
2043 }
2044 spin_unlock_bh(lock);
2045 st->state = TCP_SEQ_STATE_ESTABLISHED;
2046 }
2047 out:
2048 return rc;
2049 }
2050
established_get_next(struct seq_file * seq,void * cur)2051 static void *established_get_next(struct seq_file *seq, void *cur)
2052 {
2053 struct sock *sk = cur;
2054 struct inet_timewait_sock *tw;
2055 struct hlist_nulls_node *node;
2056 struct tcp_iter_state *st = seq->private;
2057 struct net *net = seq_file_net(seq);
2058
2059 ++st->num;
2060
2061 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2062 tw = cur;
2063 tw = tw_next(tw);
2064 get_tw:
2065 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2066 tw = tw_next(tw);
2067 }
2068 if (tw) {
2069 cur = tw;
2070 goto out;
2071 }
2072 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2073 st->state = TCP_SEQ_STATE_ESTABLISHED;
2074
2075 /* Look for next non empty bucket */
2076 while (++st->bucket < tcp_hashinfo.ehash_size &&
2077 empty_bucket(st))
2078 ;
2079 if (st->bucket >= tcp_hashinfo.ehash_size)
2080 return NULL;
2081
2082 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2083 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2084 } else
2085 sk = sk_nulls_next(sk);
2086
2087 sk_nulls_for_each_from(sk, node) {
2088 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2089 goto found;
2090 }
2091
2092 st->state = TCP_SEQ_STATE_TIME_WAIT;
2093 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2094 goto get_tw;
2095 found:
2096 cur = sk;
2097 out:
2098 return cur;
2099 }
2100
established_get_idx(struct seq_file * seq,loff_t pos)2101 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2102 {
2103 void *rc = established_get_first(seq);
2104
2105 while (rc && pos) {
2106 rc = established_get_next(seq, rc);
2107 --pos;
2108 }
2109 return rc;
2110 }
2111
tcp_get_idx(struct seq_file * seq,loff_t pos)2112 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2113 {
2114 void *rc;
2115 struct tcp_iter_state *st = seq->private;
2116
2117 st->state = TCP_SEQ_STATE_LISTENING;
2118 rc = listening_get_idx(seq, &pos);
2119
2120 if (!rc) {
2121 st->state = TCP_SEQ_STATE_ESTABLISHED;
2122 rc = established_get_idx(seq, pos);
2123 }
2124
2125 return rc;
2126 }
2127
tcp_seq_start(struct seq_file * seq,loff_t * pos)2128 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2129 {
2130 struct tcp_iter_state *st = seq->private;
2131 st->state = TCP_SEQ_STATE_LISTENING;
2132 st->num = 0;
2133 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2134 }
2135
tcp_seq_next(struct seq_file * seq,void * v,loff_t * pos)2136 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2137 {
2138 void *rc = NULL;
2139 struct tcp_iter_state *st;
2140
2141 if (v == SEQ_START_TOKEN) {
2142 rc = tcp_get_idx(seq, 0);
2143 goto out;
2144 }
2145 st = seq->private;
2146
2147 switch (st->state) {
2148 case TCP_SEQ_STATE_OPENREQ:
2149 case TCP_SEQ_STATE_LISTENING:
2150 rc = listening_get_next(seq, v);
2151 if (!rc) {
2152 st->state = TCP_SEQ_STATE_ESTABLISHED;
2153 rc = established_get_first(seq);
2154 }
2155 break;
2156 case TCP_SEQ_STATE_ESTABLISHED:
2157 case TCP_SEQ_STATE_TIME_WAIT:
2158 rc = established_get_next(seq, v);
2159 break;
2160 }
2161 out:
2162 ++*pos;
2163 return rc;
2164 }
2165
tcp_seq_stop(struct seq_file * seq,void * v)2166 static void tcp_seq_stop(struct seq_file *seq, void *v)
2167 {
2168 struct tcp_iter_state *st = seq->private;
2169
2170 switch (st->state) {
2171 case TCP_SEQ_STATE_OPENREQ:
2172 if (v) {
2173 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2174 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2175 }
2176 case TCP_SEQ_STATE_LISTENING:
2177 if (v != SEQ_START_TOKEN)
2178 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2179 break;
2180 case TCP_SEQ_STATE_TIME_WAIT:
2181 case TCP_SEQ_STATE_ESTABLISHED:
2182 if (v)
2183 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2184 break;
2185 }
2186 }
2187
tcp_seq_open(struct inode * inode,struct file * file)2188 static int tcp_seq_open(struct inode *inode, struct file *file)
2189 {
2190 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2191 struct tcp_iter_state *s;
2192 int err;
2193
2194 err = seq_open_net(inode, file, &afinfo->seq_ops,
2195 sizeof(struct tcp_iter_state));
2196 if (err < 0)
2197 return err;
2198
2199 s = ((struct seq_file *)file->private_data)->private;
2200 s->family = afinfo->family;
2201 return 0;
2202 }
2203
tcp_proc_register(struct net * net,struct tcp_seq_afinfo * afinfo)2204 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2205 {
2206 int rc = 0;
2207 struct proc_dir_entry *p;
2208
2209 afinfo->seq_fops.open = tcp_seq_open;
2210 afinfo->seq_fops.read = seq_read;
2211 afinfo->seq_fops.llseek = seq_lseek;
2212 afinfo->seq_fops.release = seq_release_net;
2213
2214 afinfo->seq_ops.start = tcp_seq_start;
2215 afinfo->seq_ops.next = tcp_seq_next;
2216 afinfo->seq_ops.stop = tcp_seq_stop;
2217
2218 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2219 &afinfo->seq_fops, afinfo);
2220 if (!p)
2221 rc = -ENOMEM;
2222 return rc;
2223 }
2224
tcp_proc_unregister(struct net * net,struct tcp_seq_afinfo * afinfo)2225 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2226 {
2227 proc_net_remove(net, afinfo->name);
2228 }
2229
get_openreq4(struct sock * sk,struct request_sock * req,struct seq_file * f,int i,int uid,int * len)2230 static void get_openreq4(struct sock *sk, struct request_sock *req,
2231 struct seq_file *f, int i, int uid, int *len)
2232 {
2233 const struct inet_request_sock *ireq = inet_rsk(req);
2234 int ttd = req->expires - jiffies;
2235
2236 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2237 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
2238 i,
2239 ireq->loc_addr,
2240 ntohs(inet_sk(sk)->sport),
2241 ireq->rmt_addr,
2242 ntohs(ireq->rmt_port),
2243 TCP_SYN_RECV,
2244 0, 0, /* could print option size, but that is af dependent. */
2245 1, /* timers active (only the expire timer) */
2246 jiffies_to_clock_t(ttd),
2247 req->retrans,
2248 uid,
2249 0, /* non standard timer */
2250 0, /* open_requests have no inode */
2251 atomic_read(&sk->sk_refcnt),
2252 req,
2253 len);
2254 }
2255
get_tcp4_sock(struct sock * sk,struct seq_file * f,int i,int * len)2256 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2257 {
2258 int timer_active;
2259 unsigned long timer_expires;
2260 struct tcp_sock *tp = tcp_sk(sk);
2261 const struct inet_connection_sock *icsk = inet_csk(sk);
2262 struct inet_sock *inet = inet_sk(sk);
2263 __be32 dest = inet->daddr;
2264 __be32 src = inet->rcv_saddr;
2265 __u16 destp = ntohs(inet->dport);
2266 __u16 srcp = ntohs(inet->sport);
2267
2268 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2269 timer_active = 1;
2270 timer_expires = icsk->icsk_timeout;
2271 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2272 timer_active = 4;
2273 timer_expires = icsk->icsk_timeout;
2274 } else if (timer_pending(&sk->sk_timer)) {
2275 timer_active = 2;
2276 timer_expires = sk->sk_timer.expires;
2277 } else {
2278 timer_active = 0;
2279 timer_expires = jiffies;
2280 }
2281
2282 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2283 "%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
2284 i, src, srcp, dest, destp, sk->sk_state,
2285 tp->write_seq - tp->snd_una,
2286 sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
2287 (tp->rcv_nxt - tp->copied_seq),
2288 timer_active,
2289 jiffies_to_clock_t(timer_expires - jiffies),
2290 icsk->icsk_retransmits,
2291 sock_i_uid(sk),
2292 icsk->icsk_probes_out,
2293 sock_i_ino(sk),
2294 atomic_read(&sk->sk_refcnt), sk,
2295 jiffies_to_clock_t(icsk->icsk_rto),
2296 jiffies_to_clock_t(icsk->icsk_ack.ato),
2297 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2298 tp->snd_cwnd,
2299 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
2300 len);
2301 }
2302
get_timewait4_sock(struct inet_timewait_sock * tw,struct seq_file * f,int i,int * len)2303 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2304 struct seq_file *f, int i, int *len)
2305 {
2306 __be32 dest, src;
2307 __u16 destp, srcp;
2308 int ttd = tw->tw_ttd - jiffies;
2309
2310 if (ttd < 0)
2311 ttd = 0;
2312
2313 dest = tw->tw_daddr;
2314 src = tw->tw_rcv_saddr;
2315 destp = ntohs(tw->tw_dport);
2316 srcp = ntohs(tw->tw_sport);
2317
2318 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2319 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
2320 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2321 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2322 atomic_read(&tw->tw_refcnt), tw, len);
2323 }
2324
2325 #define TMPSZ 150
2326
tcp4_seq_show(struct seq_file * seq,void * v)2327 static int tcp4_seq_show(struct seq_file *seq, void *v)
2328 {
2329 struct tcp_iter_state *st;
2330 int len;
2331
2332 if (v == SEQ_START_TOKEN) {
2333 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2334 " sl local_address rem_address st tx_queue "
2335 "rx_queue tr tm->when retrnsmt uid timeout "
2336 "inode");
2337 goto out;
2338 }
2339 st = seq->private;
2340
2341 switch (st->state) {
2342 case TCP_SEQ_STATE_LISTENING:
2343 case TCP_SEQ_STATE_ESTABLISHED:
2344 get_tcp4_sock(v, seq, st->num, &len);
2345 break;
2346 case TCP_SEQ_STATE_OPENREQ:
2347 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2348 break;
2349 case TCP_SEQ_STATE_TIME_WAIT:
2350 get_timewait4_sock(v, seq, st->num, &len);
2351 break;
2352 }
2353 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2354 out:
2355 return 0;
2356 }
2357
2358 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2359 .name = "tcp",
2360 .family = AF_INET,
2361 .seq_fops = {
2362 .owner = THIS_MODULE,
2363 },
2364 .seq_ops = {
2365 .show = tcp4_seq_show,
2366 },
2367 };
2368
tcp4_proc_init_net(struct net * net)2369 static int tcp4_proc_init_net(struct net *net)
2370 {
2371 return tcp_proc_register(net, &tcp4_seq_afinfo);
2372 }
2373
tcp4_proc_exit_net(struct net * net)2374 static void tcp4_proc_exit_net(struct net *net)
2375 {
2376 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2377 }
2378
2379 static struct pernet_operations tcp4_net_ops = {
2380 .init = tcp4_proc_init_net,
2381 .exit = tcp4_proc_exit_net,
2382 };
2383
tcp4_proc_init(void)2384 int __init tcp4_proc_init(void)
2385 {
2386 return register_pernet_subsys(&tcp4_net_ops);
2387 }
2388
tcp4_proc_exit(void)2389 void tcp4_proc_exit(void)
2390 {
2391 unregister_pernet_subsys(&tcp4_net_ops);
2392 }
2393 #endif /* CONFIG_PROC_FS */
2394
tcp4_gro_receive(struct sk_buff ** head,struct sk_buff * skb)2395 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2396 {
2397 struct iphdr *iph = ip_hdr(skb);
2398
2399 switch (skb->ip_summed) {
2400 case CHECKSUM_COMPLETE:
2401 if (!tcp_v4_check(skb->len, iph->saddr, iph->daddr,
2402 skb->csum)) {
2403 skb->ip_summed = CHECKSUM_UNNECESSARY;
2404 break;
2405 }
2406
2407 /* fall through */
2408 case CHECKSUM_NONE:
2409 NAPI_GRO_CB(skb)->flush = 1;
2410 return NULL;
2411 }
2412
2413 return tcp_gro_receive(head, skb);
2414 }
2415 EXPORT_SYMBOL(tcp4_gro_receive);
2416
tcp4_gro_complete(struct sk_buff * skb)2417 int tcp4_gro_complete(struct sk_buff *skb)
2418 {
2419 struct iphdr *iph = ip_hdr(skb);
2420 struct tcphdr *th = tcp_hdr(skb);
2421
2422 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2423 iph->saddr, iph->daddr, 0);
2424 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2425
2426 return tcp_gro_complete(skb);
2427 }
2428 EXPORT_SYMBOL(tcp4_gro_complete);
2429
2430 struct proto tcp_prot = {
2431 .name = "TCP",
2432 .owner = THIS_MODULE,
2433 .close = tcp_close,
2434 .connect = tcp_v4_connect,
2435 .disconnect = tcp_disconnect,
2436 .accept = inet_csk_accept,
2437 .ioctl = tcp_ioctl,
2438 .init = tcp_v4_init_sock,
2439 .destroy = tcp_v4_destroy_sock,
2440 .shutdown = tcp_shutdown,
2441 .setsockopt = tcp_setsockopt,
2442 .getsockopt = tcp_getsockopt,
2443 .recvmsg = tcp_recvmsg,
2444 .backlog_rcv = tcp_v4_do_rcv,
2445 .hash = inet_hash,
2446 .unhash = inet_unhash,
2447 .get_port = inet_csk_get_port,
2448 .enter_memory_pressure = tcp_enter_memory_pressure,
2449 .sockets_allocated = &tcp_sockets_allocated,
2450 .orphan_count = &tcp_orphan_count,
2451 .memory_allocated = &tcp_memory_allocated,
2452 .memory_pressure = &tcp_memory_pressure,
2453 .sysctl_mem = sysctl_tcp_mem,
2454 .sysctl_wmem = sysctl_tcp_wmem,
2455 .sysctl_rmem = sysctl_tcp_rmem,
2456 .max_header = MAX_TCP_HEADER,
2457 .obj_size = sizeof(struct tcp_sock),
2458 .slab_flags = SLAB_DESTROY_BY_RCU,
2459 .twsk_prot = &tcp_timewait_sock_ops,
2460 .rsk_prot = &tcp_request_sock_ops,
2461 .h.hashinfo = &tcp_hashinfo,
2462 #ifdef CONFIG_COMPAT
2463 .compat_setsockopt = compat_tcp_setsockopt,
2464 .compat_getsockopt = compat_tcp_getsockopt,
2465 #endif
2466 };
2467
2468
tcp_sk_init(struct net * net)2469 static int __net_init tcp_sk_init(struct net *net)
2470 {
2471 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2472 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2473 }
2474
tcp_sk_exit(struct net * net)2475 static void __net_exit tcp_sk_exit(struct net *net)
2476 {
2477 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2478 inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
2479 }
2480
2481 static struct pernet_operations __net_initdata tcp_sk_ops = {
2482 .init = tcp_sk_init,
2483 .exit = tcp_sk_exit,
2484 };
2485
tcp_v4_init(void)2486 void __init tcp_v4_init(void)
2487 {
2488 inet_hashinfo_init(&tcp_hashinfo);
2489 if (register_pernet_subsys(&tcp_sk_ops))
2490 panic("Failed to create the TCP control socket.\n");
2491 }
2492
2493 EXPORT_SYMBOL(ipv4_specific);
2494 EXPORT_SYMBOL(tcp_hashinfo);
2495 EXPORT_SYMBOL(tcp_prot);
2496 EXPORT_SYMBOL(tcp_v4_conn_request);
2497 EXPORT_SYMBOL(tcp_v4_connect);
2498 EXPORT_SYMBOL(tcp_v4_do_rcv);
2499 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2500 EXPORT_SYMBOL(tcp_v4_send_check);
2501 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2502
2503 #ifdef CONFIG_PROC_FS
2504 EXPORT_SYMBOL(tcp_proc_register);
2505 EXPORT_SYMBOL(tcp_proc_unregister);
2506 #endif
2507 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2508