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Merge branch 'x86/rdrand' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
[wandboard.git] / net / ipv4 / tcp_ipv4.c
blob1eb4ad57670eb0f47c4a3ecde927819cb83ef12f
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 #include <net/tcp_memcontrol.h>
77
78 #include <linux/inet.h>
79 #include <linux/ipv6.h>
80 #include <linux/stddef.h>
81 #include <linux/proc_fs.h>
82 #include <linux/seq_file.h>
83
84 #include <linux/crypto.h>
85 #include <linux/scatterlist.h>
86
87 int sysctl_tcp_tw_reuse __read_mostly;
88 int sysctl_tcp_low_latency __read_mostly;
89 EXPORT_SYMBOL(sysctl_tcp_low_latency);
90
91
92 #ifdef CONFIG_TCP_MD5SIG
93 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
94 __be32 addr);
95 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
96 __be32 daddr, __be32 saddr, const struct tcphdr *th);
97 #else
98 static inline
99 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
100 {
101 return NULL;
102 }
103 #endif
104
105 struct inet_hashinfo tcp_hashinfo;
106 EXPORT_SYMBOL(tcp_hashinfo);
107
108 static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
109 {
110 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
111 ip_hdr(skb)->saddr,
112 tcp_hdr(skb)->dest,
113 tcp_hdr(skb)->source);
114 }
115
116 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
117 {
118 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
119 struct tcp_sock *tp = tcp_sk(sk);
120
121 /* With PAWS, it is safe from the viewpoint
122 of data integrity. Even without PAWS it is safe provided sequence
123 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
124
125 Actually, the idea is close to VJ's one, only timestamp cache is
126 held not per host, but per port pair and TW bucket is used as state
127 holder.
128
129 If TW bucket has been already destroyed we fall back to VJ's scheme
130 and use initial timestamp retrieved from peer table.
131 */
132 if (tcptw->tw_ts_recent_stamp &&
133 (twp == NULL || (sysctl_tcp_tw_reuse &&
134 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
135 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
136 if (tp->write_seq == 0)
137 tp->write_seq = 1;
138 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
139 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
140 sock_hold(sktw);
141 return 1;
142 }
143
144 return 0;
145 }
146 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
147
148 /* This will initiate an outgoing connection. */
149 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
150 {
151 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
152 struct inet_sock *inet = inet_sk(sk);
153 struct tcp_sock *tp = tcp_sk(sk);
154 __be16 orig_sport, orig_dport;
155 __be32 daddr, nexthop;
156 struct flowi4 *fl4;
157 struct rtable *rt;
158 int err;
159 struct ip_options_rcu *inet_opt;
160
161 if (addr_len < sizeof(struct sockaddr_in))
162 return -EINVAL;
163
164 if (usin->sin_family != AF_INET)
165 return -EAFNOSUPPORT;
166
167 nexthop = daddr = usin->sin_addr.s_addr;
168 inet_opt = rcu_dereference_protected(inet->inet_opt,
169 sock_owned_by_user(sk));
170 if (inet_opt && inet_opt->opt.srr) {
171 if (!daddr)
172 return -EINVAL;
173 nexthop = inet_opt->opt.faddr;
174 }
175
176 orig_sport = inet->inet_sport;
177 orig_dport = usin->sin_port;
178 fl4 = &inet->cork.fl.u.ip4;
179 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
180 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
181 IPPROTO_TCP,
182 orig_sport, orig_dport, sk, true);
183 if (IS_ERR(rt)) {
184 err = PTR_ERR(rt);
185 if (err == -ENETUNREACH)
186 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
187 return err;
188 }
189
190 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
191 ip_rt_put(rt);
192 return -ENETUNREACH;
193 }
194
195 if (!inet_opt || !inet_opt->opt.srr)
196 daddr = fl4->daddr;
197
198 if (!inet->inet_saddr)
199 inet->inet_saddr = fl4->saddr;
200 inet->inet_rcv_saddr = inet->inet_saddr;
201
202 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
203 /* Reset inherited state */
204 tp->rx_opt.ts_recent = 0;
205 tp->rx_opt.ts_recent_stamp = 0;
206 tp->write_seq = 0;
207 }
208
209 if (tcp_death_row.sysctl_tw_recycle &&
210 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
211 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
212 /*
213 * VJ's idea. We save last timestamp seen from
214 * the destination in peer table, when entering state
215 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
216 * when trying new connection.
217 */
218 if (peer) {
219 inet_peer_refcheck(peer);
220 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
221 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
222 tp->rx_opt.ts_recent = peer->tcp_ts;
223 }
224 }
225 }
226
227 inet->inet_dport = usin->sin_port;
228 inet->inet_daddr = daddr;
229
230 inet_csk(sk)->icsk_ext_hdr_len = 0;
231 if (inet_opt)
232 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
233
234 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
235
236 /* Socket identity is still unknown (sport may be zero).
237 * However we set state to SYN-SENT and not releasing socket
238 * lock select source port, enter ourselves into the hash tables and
239 * complete initialization after this.
240 */
241 tcp_set_state(sk, TCP_SYN_SENT);
242 err = inet_hash_connect(&tcp_death_row, sk);
243 if (err)
244 goto failure;
245
246 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
247 inet->inet_sport, inet->inet_dport, sk);
248 if (IS_ERR(rt)) {
249 err = PTR_ERR(rt);
250 rt = NULL;
251 goto failure;
252 }
253 /* OK, now commit destination to socket. */
254 sk->sk_gso_type = SKB_GSO_TCPV4;
255 sk_setup_caps(sk, &rt->dst);
256
257 if (!tp->write_seq)
258 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
259 inet->inet_daddr,
260 inet->inet_sport,
261 usin->sin_port);
262
263 inet->inet_id = tp->write_seq ^ jiffies;
264
265 err = tcp_connect(sk);
266 rt = NULL;
267 if (err)
268 goto failure;
269
270 return 0;
271
272 failure:
273 /*
274 * This unhashes the socket and releases the local port,
275 * if necessary.
276 */
277 tcp_set_state(sk, TCP_CLOSE);
278 ip_rt_put(rt);
279 sk->sk_route_caps = 0;
280 inet->inet_dport = 0;
281 return err;
282 }
283 EXPORT_SYMBOL(tcp_v4_connect);
284
285 /*
286 * This routine does path mtu discovery as defined in RFC1191.
287 */
288 static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
289 {
290 struct dst_entry *dst;
291 struct inet_sock *inet = inet_sk(sk);
292
293 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
294 * send out by Linux are always <576bytes so they should go through
295 * unfragmented).
296 */
297 if (sk->sk_state == TCP_LISTEN)
298 return;
299
300 /* We don't check in the destentry if pmtu discovery is forbidden
301 * on this route. We just assume that no packet_to_big packets
302 * are send back when pmtu discovery is not active.
303 * There is a small race when the user changes this flag in the
304 * route, but I think that's acceptable.
305 */
306 if ((dst = __sk_dst_check(sk, 0)) == NULL)
307 return;
308
309 dst->ops->update_pmtu(dst, mtu);
310
311 /* Something is about to be wrong... Remember soft error
312 * for the case, if this connection will not able to recover.
313 */
314 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
315 sk->sk_err_soft = EMSGSIZE;
316
317 mtu = dst_mtu(dst);
318
319 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
320 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
321 tcp_sync_mss(sk, mtu);
322
323 /* Resend the TCP packet because it's
324 * clear that the old packet has been
325 * dropped. This is the new "fast" path mtu
326 * discovery.
327 */
328 tcp_simple_retransmit(sk);
329 } /* else let the usual retransmit timer handle it */
330 }
331
332 /*
333 * This routine is called by the ICMP module when it gets some
334 * sort of error condition. If err < 0 then the socket should
335 * be closed and the error returned to the user. If err > 0
336 * it's just the icmp type << 8 | icmp code. After adjustment
337 * header points to the first 8 bytes of the tcp header. We need
338 * to find the appropriate port.
339 *
340 * The locking strategy used here is very "optimistic". When
341 * someone else accesses the socket the ICMP is just dropped
342 * and for some paths there is no check at all.
343 * A more general error queue to queue errors for later handling
344 * is probably better.
345 *
346 */
347
348 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
349 {
350 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
351 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
352 struct inet_connection_sock *icsk;
353 struct tcp_sock *tp;
354 struct inet_sock *inet;
355 const int type = icmp_hdr(icmp_skb)->type;
356 const int code = icmp_hdr(icmp_skb)->code;
357 struct sock *sk;
358 struct sk_buff *skb;
359 __u32 seq;
360 __u32 remaining;
361 int err;
362 struct net *net = dev_net(icmp_skb->dev);
363
364 if (icmp_skb->len < (iph->ihl << 2) + 8) {
365 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
366 return;
367 }
368
369 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
370 iph->saddr, th->source, inet_iif(icmp_skb));
371 if (!sk) {
372 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
373 return;
374 }
375 if (sk->sk_state == TCP_TIME_WAIT) {
376 inet_twsk_put(inet_twsk(sk));
377 return;
378 }
379
380 bh_lock_sock(sk);
381 /* If too many ICMPs get dropped on busy
382 * servers this needs to be solved differently.
383 */
384 if (sock_owned_by_user(sk))
385 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
386
387 if (sk->sk_state == TCP_CLOSE)
388 goto out;
389
390 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
391 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
392 goto out;
393 }
394
395 icsk = inet_csk(sk);
396 tp = tcp_sk(sk);
397 seq = ntohl(th->seq);
398 if (sk->sk_state != TCP_LISTEN &&
399 !between(seq, tp->snd_una, tp->snd_nxt)) {
400 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
401 goto out;
402 }
403
404 switch (type) {
405 case ICMP_SOURCE_QUENCH:
406 /* Just silently ignore these. */
407 goto out;
408 case ICMP_PARAMETERPROB:
409 err = EPROTO;
410 break;
411 case ICMP_DEST_UNREACH:
412 if (code > NR_ICMP_UNREACH)
413 goto out;
414
415 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
416 if (!sock_owned_by_user(sk))
417 do_pmtu_discovery(sk, iph, info);
418 goto out;
419 }
420
421 err = icmp_err_convert[code].errno;
422 /* check if icmp_skb allows revert of backoff
423 * (see draft-zimmermann-tcp-lcd) */
424 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
425 break;
426 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
427 !icsk->icsk_backoff)
428 break;
429
430 if (sock_owned_by_user(sk))
431 break;
432
433 icsk->icsk_backoff--;
434 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
435 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
436 tcp_bound_rto(sk);
437
438 skb = tcp_write_queue_head(sk);
439 BUG_ON(!skb);
440
441 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
442 tcp_time_stamp - TCP_SKB_CB(skb)->when);
443
444 if (remaining) {
445 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
446 remaining, TCP_RTO_MAX);
447 } else {
448 /* RTO revert clocked out retransmission.
449 * Will retransmit now */
450 tcp_retransmit_timer(sk);
451 }
452
453 break;
454 case ICMP_TIME_EXCEEDED:
455 err = EHOSTUNREACH;
456 break;
457 default:
458 goto out;
459 }
460
461 switch (sk->sk_state) {
462 struct request_sock *req, **prev;
463 case TCP_LISTEN:
464 if (sock_owned_by_user(sk))
465 goto out;
466
467 req = inet_csk_search_req(sk, &prev, th->dest,
468 iph->daddr, iph->saddr);
469 if (!req)
470 goto out;
471
472 /* ICMPs are not backlogged, hence we cannot get
473 an established socket here.
474 */
475 WARN_ON(req->sk);
476
477 if (seq != tcp_rsk(req)->snt_isn) {
478 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
479 goto out;
480 }
481
482 /*
483 * Still in SYN_RECV, just remove it silently.
484 * There is no good way to pass the error to the newly
485 * created socket, and POSIX does not want network
486 * errors returned from accept().
487 */
488 inet_csk_reqsk_queue_drop(sk, req, prev);
489 goto out;
490
491 case TCP_SYN_SENT:
492 case TCP_SYN_RECV: /* Cannot happen.
493 It can f.e. if SYNs crossed.
494 */
495 if (!sock_owned_by_user(sk)) {
496 sk->sk_err = err;
497
498 sk->sk_error_report(sk);
499
500 tcp_done(sk);
501 } else {
502 sk->sk_err_soft = err;
503 }
504 goto out;
505 }
506
507 /* If we've already connected we will keep trying
508 * until we time out, or the user gives up.
509 *
510 * rfc1122 4.2.3.9 allows to consider as hard errors
511 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
512 * but it is obsoleted by pmtu discovery).
513 *
514 * Note, that in modern internet, where routing is unreliable
515 * and in each dark corner broken firewalls sit, sending random
516 * errors ordered by their masters even this two messages finally lose
517 * their original sense (even Linux sends invalid PORT_UNREACHs)
518 *
519 * Now we are in compliance with RFCs.
520 * --ANK (980905)
521 */
522
523 inet = inet_sk(sk);
524 if (!sock_owned_by_user(sk) && inet->recverr) {
525 sk->sk_err = err;
526 sk->sk_error_report(sk);
527 } else { /* Only an error on timeout */
528 sk->sk_err_soft = err;
529 }
530
531 out:
532 bh_unlock_sock(sk);
533 sock_put(sk);
534 }
535
536 static void __tcp_v4_send_check(struct sk_buff *skb,
537 __be32 saddr, __be32 daddr)
538 {
539 struct tcphdr *th = tcp_hdr(skb);
540
541 if (skb->ip_summed == CHECKSUM_PARTIAL) {
542 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
543 skb->csum_start = skb_transport_header(skb) - skb->head;
544 skb->csum_offset = offsetof(struct tcphdr, check);
545 } else {
546 th->check = tcp_v4_check(skb->len, saddr, daddr,
547 csum_partial(th,
548 th->doff << 2,
549 skb->csum));
550 }
551 }
552
553 /* This routine computes an IPv4 TCP checksum. */
554 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
555 {
556 const struct inet_sock *inet = inet_sk(sk);
557
558 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
559 }
560 EXPORT_SYMBOL(tcp_v4_send_check);
561
562 int tcp_v4_gso_send_check(struct sk_buff *skb)
563 {
564 const struct iphdr *iph;
565 struct tcphdr *th;
566
567 if (!pskb_may_pull(skb, sizeof(*th)))
568 return -EINVAL;
569
570 iph = ip_hdr(skb);
571 th = tcp_hdr(skb);
572
573 th->check = 0;
574 skb->ip_summed = CHECKSUM_PARTIAL;
575 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
576 return 0;
577 }
578
579 /*
580 * This routine will send an RST to the other tcp.
581 *
582 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
583 * for reset.
584 * Answer: if a packet caused RST, it is not for a socket
585 * existing in our system, if it is matched to a socket,
586 * it is just duplicate segment or bug in other side's TCP.
587 * So that we build reply only basing on parameters
588 * arrived with segment.
589 * Exception: precedence violation. We do not implement it in any case.
590 */
591
592 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
593 {
594 const struct tcphdr *th = tcp_hdr(skb);
595 struct {
596 struct tcphdr th;
597 #ifdef CONFIG_TCP_MD5SIG
598 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
599 #endif
600 } rep;
601 struct ip_reply_arg arg;
602 #ifdef CONFIG_TCP_MD5SIG
603 struct tcp_md5sig_key *key;
604 #endif
605 struct net *net;
606
607 /* Never send a reset in response to a reset. */
608 if (th->rst)
609 return;
610
611 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
612 return;
613
614 /* Swap the send and the receive. */
615 memset(&rep, 0, sizeof(rep));
616 rep.th.dest = th->source;
617 rep.th.source = th->dest;
618 rep.th.doff = sizeof(struct tcphdr) / 4;
619 rep.th.rst = 1;
620
621 if (th->ack) {
622 rep.th.seq = th->ack_seq;
623 } else {
624 rep.th.ack = 1;
625 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
626 skb->len - (th->doff << 2));
627 }
628
629 memset(&arg, 0, sizeof(arg));
630 arg.iov[0].iov_base = (unsigned char *)&rep;
631 arg.iov[0].iov_len = sizeof(rep.th);
632
633 #ifdef CONFIG_TCP_MD5SIG
634 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
635 if (key) {
636 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
637 (TCPOPT_NOP << 16) |
638 (TCPOPT_MD5SIG << 8) |
639 TCPOLEN_MD5SIG);
640 /* Update length and the length the header thinks exists */
641 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
642 rep.th.doff = arg.iov[0].iov_len / 4;
643
644 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
645 key, ip_hdr(skb)->saddr,
646 ip_hdr(skb)->daddr, &rep.th);
647 }
648 #endif
649 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
650 ip_hdr(skb)->saddr, /* XXX */
651 arg.iov[0].iov_len, IPPROTO_TCP, 0);
652 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
653 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
654
655 net = dev_net(skb_dst(skb)->dev);
656 arg.tos = ip_hdr(skb)->tos;
657 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
658 &arg, arg.iov[0].iov_len);
659
660 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
661 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
662 }
663
664 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
665 outside socket context is ugly, certainly. What can I do?
666 */
667
668 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
669 u32 win, u32 ts, int oif,
670 struct tcp_md5sig_key *key,
671 int reply_flags, u8 tos)
672 {
673 const struct tcphdr *th = tcp_hdr(skb);
674 struct {
675 struct tcphdr th;
676 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
677 #ifdef CONFIG_TCP_MD5SIG
678 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
679 #endif
680 ];
681 } rep;
682 struct ip_reply_arg arg;
683 struct net *net = dev_net(skb_dst(skb)->dev);
684
685 memset(&rep.th, 0, sizeof(struct tcphdr));
686 memset(&arg, 0, sizeof(arg));
687
688 arg.iov[0].iov_base = (unsigned char *)&rep;
689 arg.iov[0].iov_len = sizeof(rep.th);
690 if (ts) {
691 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
692 (TCPOPT_TIMESTAMP << 8) |
693 TCPOLEN_TIMESTAMP);
694 rep.opt[1] = htonl(tcp_time_stamp);
695 rep.opt[2] = htonl(ts);
696 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
697 }
698
699 /* Swap the send and the receive. */
700 rep.th.dest = th->source;
701 rep.th.source = th->dest;
702 rep.th.doff = arg.iov[0].iov_len / 4;
703 rep.th.seq = htonl(seq);
704 rep.th.ack_seq = htonl(ack);
705 rep.th.ack = 1;
706 rep.th.window = htons(win);
707
708 #ifdef CONFIG_TCP_MD5SIG
709 if (key) {
710 int offset = (ts) ? 3 : 0;
711
712 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
713 (TCPOPT_NOP << 16) |
714 (TCPOPT_MD5SIG << 8) |
715 TCPOLEN_MD5SIG);
716 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
717 rep.th.doff = arg.iov[0].iov_len/4;
718
719 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
720 key, ip_hdr(skb)->saddr,
721 ip_hdr(skb)->daddr, &rep.th);
722 }
723 #endif
724 arg.flags = reply_flags;
725 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
726 ip_hdr(skb)->saddr, /* XXX */
727 arg.iov[0].iov_len, IPPROTO_TCP, 0);
728 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
729 if (oif)
730 arg.bound_dev_if = oif;
731 arg.tos = tos;
732 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
733 &arg, arg.iov[0].iov_len);
734
735 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
736 }
737
738 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
739 {
740 struct inet_timewait_sock *tw = inet_twsk(sk);
741 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
742
743 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
744 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
745 tcptw->tw_ts_recent,
746 tw->tw_bound_dev_if,
747 tcp_twsk_md5_key(tcptw),
748 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
749 tw->tw_tos
750 );
751
752 inet_twsk_put(tw);
753 }
754
755 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
756 struct request_sock *req)
757 {
758 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
759 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
760 req->ts_recent,
761 0,
762 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
763 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
764 ip_hdr(skb)->tos);
765 }
766
767 /*
768 * Send a SYN-ACK after having received a SYN.
769 * This still operates on a request_sock only, not on a big
770 * socket.
771 */
772 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
773 struct request_sock *req,
774 struct request_values *rvp)
775 {
776 const struct inet_request_sock *ireq = inet_rsk(req);
777 struct flowi4 fl4;
778 int err = -1;
779 struct sk_buff * skb;
780
781 /* First, grab a route. */
782 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
783 return -1;
784
785 skb = tcp_make_synack(sk, dst, req, rvp);
786
787 if (skb) {
788 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
789
790 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
791 ireq->rmt_addr,
792 ireq->opt);
793 err = net_xmit_eval(err);
794 }
795
796 dst_release(dst);
797 return err;
798 }
799
800 static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
801 struct request_values *rvp)
802 {
803 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
804 return tcp_v4_send_synack(sk, NULL, req, rvp);
805 }
806
807 /*
808 * IPv4 request_sock destructor.
809 */
810 static void tcp_v4_reqsk_destructor(struct request_sock *req)
811 {
812 kfree(inet_rsk(req)->opt);
813 }
814
815 /*
816 * Return 1 if a syncookie should be sent
817 */
818 int tcp_syn_flood_action(struct sock *sk,
819 const struct sk_buff *skb,
820 const char *proto)
821 {
822 const char *msg = "Dropping request";
823 int want_cookie = 0;
824 struct listen_sock *lopt;
825
826
827
828 #ifdef CONFIG_SYN_COOKIES
829 if (sysctl_tcp_syncookies) {
830 msg = "Sending cookies";
831 want_cookie = 1;
832 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
833 } else
834 #endif
835 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
836
837 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
838 if (!lopt->synflood_warned) {
839 lopt->synflood_warned = 1;
840 pr_info("%s: Possible SYN flooding on port %d. %s. "
841 " Check SNMP counters.\n",
842 proto, ntohs(tcp_hdr(skb)->dest), msg);
843 }
844 return want_cookie;
845 }
846 EXPORT_SYMBOL(tcp_syn_flood_action);
847
848 /*
849 * Save and compile IPv4 options into the request_sock if needed.
850 */
851 static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
852 struct sk_buff *skb)
853 {
854 const struct ip_options *opt = &(IPCB(skb)->opt);
855 struct ip_options_rcu *dopt = NULL;
856
857 if (opt && opt->optlen) {
858 int opt_size = sizeof(*dopt) + opt->optlen;
859
860 dopt = kmalloc(opt_size, GFP_ATOMIC);
861 if (dopt) {
862 if (ip_options_echo(&dopt->opt, skb)) {
863 kfree(dopt);
864 dopt = NULL;
865 }
866 }
867 }
868 return dopt;
869 }
870
871 #ifdef CONFIG_TCP_MD5SIG
872 /*
873 * RFC2385 MD5 checksumming requires a mapping of
874 * IP address->MD5 Key.
875 * We need to maintain these in the sk structure.
876 */
877
878 /* Find the Key structure for an address. */
879 static struct tcp_md5sig_key *
880 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
881 {
882 struct tcp_sock *tp = tcp_sk(sk);
883 int i;
884
885 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
886 return NULL;
887 for (i = 0; i < tp->md5sig_info->entries4; i++) {
888 if (tp->md5sig_info->keys4[i].addr == addr)
889 return &tp->md5sig_info->keys4[i].base;
890 }
891 return NULL;
892 }
893
894 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
895 struct sock *addr_sk)
896 {
897 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
898 }
899 EXPORT_SYMBOL(tcp_v4_md5_lookup);
900
901 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
902 struct request_sock *req)
903 {
904 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
905 }
906
907 /* This can be called on a newly created socket, from other files */
908 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
909 u8 *newkey, u8 newkeylen)
910 {
911 /* Add Key to the list */
912 struct tcp_md5sig_key *key;
913 struct tcp_sock *tp = tcp_sk(sk);
914 struct tcp4_md5sig_key *keys;
915
916 key = tcp_v4_md5_do_lookup(sk, addr);
917 if (key) {
918 /* Pre-existing entry - just update that one. */
919 kfree(key->key);
920 key->key = newkey;
921 key->keylen = newkeylen;
922 } else {
923 struct tcp_md5sig_info *md5sig;
924
925 if (!tp->md5sig_info) {
926 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
927 GFP_ATOMIC);
928 if (!tp->md5sig_info) {
929 kfree(newkey);
930 return -ENOMEM;
931 }
932 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
933 }
934
935 md5sig = tp->md5sig_info;
936 if (md5sig->entries4 == 0 &&
937 tcp_alloc_md5sig_pool(sk) == NULL) {
938 kfree(newkey);
939 return -ENOMEM;
940 }
941
942 if (md5sig->alloced4 == md5sig->entries4) {
943 keys = kmalloc((sizeof(*keys) *
944 (md5sig->entries4 + 1)), GFP_ATOMIC);
945 if (!keys) {
946 kfree(newkey);
947 if (md5sig->entries4 == 0)
948 tcp_free_md5sig_pool();
949 return -ENOMEM;
950 }
951
952 if (md5sig->entries4)
953 memcpy(keys, md5sig->keys4,
954 sizeof(*keys) * md5sig->entries4);
955
956 /* Free old key list, and reference new one */
957 kfree(md5sig->keys4);
958 md5sig->keys4 = keys;
959 md5sig->alloced4++;
960 }
961 md5sig->entries4++;
962 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
963 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
964 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
965 }
966 return 0;
967 }
968 EXPORT_SYMBOL(tcp_v4_md5_do_add);
969
970 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
971 u8 *newkey, u8 newkeylen)
972 {
973 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
974 newkey, newkeylen);
975 }
976
977 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
978 {
979 struct tcp_sock *tp = tcp_sk(sk);
980 int i;
981
982 for (i = 0; i < tp->md5sig_info->entries4; i++) {
983 if (tp->md5sig_info->keys4[i].addr == addr) {
984 /* Free the key */
985 kfree(tp->md5sig_info->keys4[i].base.key);
986 tp->md5sig_info->entries4--;
987
988 if (tp->md5sig_info->entries4 == 0) {
989 kfree(tp->md5sig_info->keys4);
990 tp->md5sig_info->keys4 = NULL;
991 tp->md5sig_info->alloced4 = 0;
992 tcp_free_md5sig_pool();
993 } else if (tp->md5sig_info->entries4 != i) {
994 /* Need to do some manipulation */
995 memmove(&tp->md5sig_info->keys4[i],
996 &tp->md5sig_info->keys4[i+1],
997 (tp->md5sig_info->entries4 - i) *
998 sizeof(struct tcp4_md5sig_key));
999 }
1000 return 0;
1001 }
1002 }
1003 return -ENOENT;
1004 }
1005 EXPORT_SYMBOL(tcp_v4_md5_do_del);
1006
1007 static void tcp_v4_clear_md5_list(struct sock *sk)
1008 {
1009 struct tcp_sock *tp = tcp_sk(sk);
1010
1011 /* Free each key, then the set of key keys,
1012 * the crypto element, and then decrement our
1013 * hold on the last resort crypto.
1014 */
1015 if (tp->md5sig_info->entries4) {
1016 int i;
1017 for (i = 0; i < tp->md5sig_info->entries4; i++)
1018 kfree(tp->md5sig_info->keys4[i].base.key);
1019 tp->md5sig_info->entries4 = 0;
1020 tcp_free_md5sig_pool();
1021 }
1022 if (tp->md5sig_info->keys4) {
1023 kfree(tp->md5sig_info->keys4);
1024 tp->md5sig_info->keys4 = NULL;
1025 tp->md5sig_info->alloced4 = 0;
1026 }
1027 }
1028
1029 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1030 int optlen)
1031 {
1032 struct tcp_md5sig cmd;
1033 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1034 u8 *newkey;
1035
1036 if (optlen < sizeof(cmd))
1037 return -EINVAL;
1038
1039 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1040 return -EFAULT;
1041
1042 if (sin->sin_family != AF_INET)
1043 return -EINVAL;
1044
1045 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
1046 if (!tcp_sk(sk)->md5sig_info)
1047 return -ENOENT;
1048 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
1049 }
1050
1051 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1052 return -EINVAL;
1053
1054 if (!tcp_sk(sk)->md5sig_info) {
1055 struct tcp_sock *tp = tcp_sk(sk);
1056 struct tcp_md5sig_info *p;
1057
1058 p = kzalloc(sizeof(*p), sk->sk_allocation);
1059 if (!p)
1060 return -EINVAL;
1061
1062 tp->md5sig_info = p;
1063 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1064 }
1065
1066 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1067 if (!newkey)
1068 return -ENOMEM;
1069 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1070 newkey, cmd.tcpm_keylen);
1071 }
1072
1073 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1074 __be32 daddr, __be32 saddr, int nbytes)
1075 {
1076 struct tcp4_pseudohdr *bp;
1077 struct scatterlist sg;
1078
1079 bp = &hp->md5_blk.ip4;
1080
1081 /*
1082 * 1. the TCP pseudo-header (in the order: source IP address,
1083 * destination IP address, zero-padded protocol number, and
1084 * segment length)
1085 */
1086 bp->saddr = saddr;
1087 bp->daddr = daddr;
1088 bp->pad = 0;
1089 bp->protocol = IPPROTO_TCP;
1090 bp->len = cpu_to_be16(nbytes);
1091
1092 sg_init_one(&sg, bp, sizeof(*bp));
1093 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1094 }
1095
1096 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1097 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1098 {
1099 struct tcp_md5sig_pool *hp;
1100 struct hash_desc *desc;
1101
1102 hp = tcp_get_md5sig_pool();
1103 if (!hp)
1104 goto clear_hash_noput;
1105 desc = &hp->md5_desc;
1106
1107 if (crypto_hash_init(desc))
1108 goto clear_hash;
1109 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1110 goto clear_hash;
1111 if (tcp_md5_hash_header(hp, th))
1112 goto clear_hash;
1113 if (tcp_md5_hash_key(hp, key))
1114 goto clear_hash;
1115 if (crypto_hash_final(desc, md5_hash))
1116 goto clear_hash;
1117
1118 tcp_put_md5sig_pool();
1119 return 0;
1120
1121 clear_hash:
1122 tcp_put_md5sig_pool();
1123 clear_hash_noput:
1124 memset(md5_hash, 0, 16);
1125 return 1;
1126 }
1127
1128 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1129 const struct sock *sk, const struct request_sock *req,
1130 const struct sk_buff *skb)
1131 {
1132 struct tcp_md5sig_pool *hp;
1133 struct hash_desc *desc;
1134 const struct tcphdr *th = tcp_hdr(skb);
1135 __be32 saddr, daddr;
1136
1137 if (sk) {
1138 saddr = inet_sk(sk)->inet_saddr;
1139 daddr = inet_sk(sk)->inet_daddr;
1140 } else if (req) {
1141 saddr = inet_rsk(req)->loc_addr;
1142 daddr = inet_rsk(req)->rmt_addr;
1143 } else {
1144 const struct iphdr *iph = ip_hdr(skb);
1145 saddr = iph->saddr;
1146 daddr = iph->daddr;
1147 }
1148
1149 hp = tcp_get_md5sig_pool();
1150 if (!hp)
1151 goto clear_hash_noput;
1152 desc = &hp->md5_desc;
1153
1154 if (crypto_hash_init(desc))
1155 goto clear_hash;
1156
1157 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1158 goto clear_hash;
1159 if (tcp_md5_hash_header(hp, th))
1160 goto clear_hash;
1161 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1162 goto clear_hash;
1163 if (tcp_md5_hash_key(hp, key))
1164 goto clear_hash;
1165 if (crypto_hash_final(desc, md5_hash))
1166 goto clear_hash;
1167
1168 tcp_put_md5sig_pool();
1169 return 0;
1170
1171 clear_hash:
1172 tcp_put_md5sig_pool();
1173 clear_hash_noput:
1174 memset(md5_hash, 0, 16);
1175 return 1;
1176 }
1177 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1178
1179 static int tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1180 {
1181 /*
1182 * This gets called for each TCP segment that arrives
1183 * so we want to be efficient.
1184 * We have 3 drop cases:
1185 * o No MD5 hash and one expected.
1186 * o MD5 hash and we're not expecting one.
1187 * o MD5 hash and its wrong.
1188 */
1189 const __u8 *hash_location = NULL;
1190 struct tcp_md5sig_key *hash_expected;
1191 const struct iphdr *iph = ip_hdr(skb);
1192 const struct tcphdr *th = tcp_hdr(skb);
1193 int genhash;
1194 unsigned char newhash[16];
1195
1196 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1197 hash_location = tcp_parse_md5sig_option(th);
1198
1199 /* We've parsed the options - do we have a hash? */
1200 if (!hash_expected && !hash_location)
1201 return 0;
1202
1203 if (hash_expected && !hash_location) {
1204 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1205 return 1;
1206 }
1207
1208 if (!hash_expected && hash_location) {
1209 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1210 return 1;
1211 }
1212
1213 /* Okay, so this is hash_expected and hash_location -
1214 * so we need to calculate the checksum.
1215 */
1216 genhash = tcp_v4_md5_hash_skb(newhash,
1217 hash_expected,
1218 NULL, NULL, skb);
1219
1220 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1221 if (net_ratelimit()) {
1222 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1223 &iph->saddr, ntohs(th->source),
1224 &iph->daddr, ntohs(th->dest),
1225 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1226 }
1227 return 1;
1228 }
1229 return 0;
1230 }
1231
1232 #endif
1233
1234 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1235 .family = PF_INET,
1236 .obj_size = sizeof(struct tcp_request_sock),
1237 .rtx_syn_ack = tcp_v4_rtx_synack,
1238 .send_ack = tcp_v4_reqsk_send_ack,
1239 .destructor = tcp_v4_reqsk_destructor,
1240 .send_reset = tcp_v4_send_reset,
1241 .syn_ack_timeout = tcp_syn_ack_timeout,
1242 };
1243
1244 #ifdef CONFIG_TCP_MD5SIG
1245 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1246 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1247 .calc_md5_hash = tcp_v4_md5_hash_skb,
1248 };
1249 #endif
1250
1251 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1252 {
1253 struct tcp_extend_values tmp_ext;
1254 struct tcp_options_received tmp_opt;
1255 const u8 *hash_location;
1256 struct request_sock *req;
1257 struct inet_request_sock *ireq;
1258 struct tcp_sock *tp = tcp_sk(sk);
1259 struct dst_entry *dst = NULL;
1260 __be32 saddr = ip_hdr(skb)->saddr;
1261 __be32 daddr = ip_hdr(skb)->daddr;
1262 __u32 isn = TCP_SKB_CB(skb)->when;
1263 int want_cookie = 0;
1264
1265 /* Never answer to SYNs send to broadcast or multicast */
1266 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1267 goto drop;
1268
1269 /* TW buckets are converted to open requests without
1270 * limitations, they conserve resources and peer is
1271 * evidently real one.
1272 */
1273 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1274 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1275 if (!want_cookie)
1276 goto drop;
1277 }
1278
1279 /* Accept backlog is full. If we have already queued enough
1280 * of warm entries in syn queue, drop request. It is better than
1281 * clogging syn queue with openreqs with exponentially increasing
1282 * timeout.
1283 */
1284 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1285 goto drop;
1286
1287 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1288 if (!req)
1289 goto drop;
1290
1291 #ifdef CONFIG_TCP_MD5SIG
1292 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1293 #endif
1294
1295 tcp_clear_options(&tmp_opt);
1296 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1297 tmp_opt.user_mss = tp->rx_opt.user_mss;
1298 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1299
1300 if (tmp_opt.cookie_plus > 0 &&
1301 tmp_opt.saw_tstamp &&
1302 !tp->rx_opt.cookie_out_never &&
1303 (sysctl_tcp_cookie_size > 0 ||
1304 (tp->cookie_values != NULL &&
1305 tp->cookie_values->cookie_desired > 0))) {
1306 u8 *c;
1307 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1308 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1309
1310 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1311 goto drop_and_release;
1312
1313 /* Secret recipe starts with IP addresses */
1314 *mess++ ^= (__force u32)daddr;
1315 *mess++ ^= (__force u32)saddr;
1316
1317 /* plus variable length Initiator Cookie */
1318 c = (u8 *)mess;
1319 while (l-- > 0)
1320 *c++ ^= *hash_location++;
1321
1322 want_cookie = 0; /* not our kind of cookie */
1323 tmp_ext.cookie_out_never = 0; /* false */
1324 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1325 } else if (!tp->rx_opt.cookie_in_always) {
1326 /* redundant indications, but ensure initialization. */
1327 tmp_ext.cookie_out_never = 1; /* true */
1328 tmp_ext.cookie_plus = 0;
1329 } else {
1330 goto drop_and_release;
1331 }
1332 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1333
1334 if (want_cookie && !tmp_opt.saw_tstamp)
1335 tcp_clear_options(&tmp_opt);
1336
1337 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1338 tcp_openreq_init(req, &tmp_opt, skb);
1339
1340 ireq = inet_rsk(req);
1341 ireq->loc_addr = daddr;
1342 ireq->rmt_addr = saddr;
1343 ireq->no_srccheck = inet_sk(sk)->transparent;
1344 ireq->opt = tcp_v4_save_options(sk, skb);
1345
1346 if (security_inet_conn_request(sk, skb, req))
1347 goto drop_and_free;
1348
1349 if (!want_cookie || tmp_opt.tstamp_ok)
1350 TCP_ECN_create_request(req, tcp_hdr(skb));
1351
1352 if (want_cookie) {
1353 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1354 req->cookie_ts = tmp_opt.tstamp_ok;
1355 } else if (!isn) {
1356 struct inet_peer *peer = NULL;
1357 struct flowi4 fl4;
1358
1359 /* VJ's idea. We save last timestamp seen
1360 * from the destination in peer table, when entering
1361 * state TIME-WAIT, and check against it before
1362 * accepting new connection request.
1363 *
1364 * If "isn" is not zero, this request hit alive
1365 * timewait bucket, so that all the necessary checks
1366 * are made in the function processing timewait state.
1367 */
1368 if (tmp_opt.saw_tstamp &&
1369 tcp_death_row.sysctl_tw_recycle &&
1370 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1371 fl4.daddr == saddr &&
1372 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1373 inet_peer_refcheck(peer);
1374 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1375 (s32)(peer->tcp_ts - req->ts_recent) >
1376 TCP_PAWS_WINDOW) {
1377 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1378 goto drop_and_release;
1379 }
1380 }
1381 /* Kill the following clause, if you dislike this way. */
1382 else if (!sysctl_tcp_syncookies &&
1383 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1384 (sysctl_max_syn_backlog >> 2)) &&
1385 (!peer || !peer->tcp_ts_stamp) &&
1386 (!dst || !dst_metric(dst, RTAX_RTT))) {
1387 /* Without syncookies last quarter of
1388 * backlog is filled with destinations,
1389 * proven to be alive.
1390 * It means that we continue to communicate
1391 * to destinations, already remembered
1392 * to the moment of synflood.
1393 */
1394 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1395 &saddr, ntohs(tcp_hdr(skb)->source));
1396 goto drop_and_release;
1397 }
1398
1399 isn = tcp_v4_init_sequence(skb);
1400 }
1401 tcp_rsk(req)->snt_isn = isn;
1402 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1403
1404 if (tcp_v4_send_synack(sk, dst, req,
1405 (struct request_values *)&tmp_ext) ||
1406 want_cookie)
1407 goto drop_and_free;
1408
1409 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1410 return 0;
1411
1412 drop_and_release:
1413 dst_release(dst);
1414 drop_and_free:
1415 reqsk_free(req);
1416 drop:
1417 return 0;
1418 }
1419 EXPORT_SYMBOL(tcp_v4_conn_request);
1420
1421
1422 /*
1423 * The three way handshake has completed - we got a valid synack -
1424 * now create the new socket.
1425 */
1426 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1427 struct request_sock *req,
1428 struct dst_entry *dst)
1429 {
1430 struct inet_request_sock *ireq;
1431 struct inet_sock *newinet;
1432 struct tcp_sock *newtp;
1433 struct sock *newsk;
1434 #ifdef CONFIG_TCP_MD5SIG
1435 struct tcp_md5sig_key *key;
1436 #endif
1437 struct ip_options_rcu *inet_opt;
1438
1439 if (sk_acceptq_is_full(sk))
1440 goto exit_overflow;
1441
1442 newsk = tcp_create_openreq_child(sk, req, skb);
1443 if (!newsk)
1444 goto exit_nonewsk;
1445
1446 newsk->sk_gso_type = SKB_GSO_TCPV4;
1447
1448 newtp = tcp_sk(newsk);
1449 newinet = inet_sk(newsk);
1450 ireq = inet_rsk(req);
1451 newinet->inet_daddr = ireq->rmt_addr;
1452 newinet->inet_rcv_saddr = ireq->loc_addr;
1453 newinet->inet_saddr = ireq->loc_addr;
1454 inet_opt = ireq->opt;
1455 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1456 ireq->opt = NULL;
1457 newinet->mc_index = inet_iif(skb);
1458 newinet->mc_ttl = ip_hdr(skb)->ttl;
1459 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1460 if (inet_opt)
1461 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1462 newinet->inet_id = newtp->write_seq ^ jiffies;
1463
1464 if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
1465 goto put_and_exit;
1466
1467 sk_setup_caps(newsk, dst);
1468
1469 tcp_mtup_init(newsk);
1470 tcp_sync_mss(newsk, dst_mtu(dst));
1471 newtp->advmss = dst_metric_advmss(dst);
1472 if (tcp_sk(sk)->rx_opt.user_mss &&
1473 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1474 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1475
1476 tcp_initialize_rcv_mss(newsk);
1477 if (tcp_rsk(req)->snt_synack)
1478 tcp_valid_rtt_meas(newsk,
1479 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1480 newtp->total_retrans = req->retrans;
1481
1482 #ifdef CONFIG_TCP_MD5SIG
1483 /* Copy over the MD5 key from the original socket */
1484 key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
1485 if (key != NULL) {
1486 /*
1487 * We're using one, so create a matching key
1488 * on the newsk structure. If we fail to get
1489 * memory, then we end up not copying the key
1490 * across. Shucks.
1491 */
1492 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1493 if (newkey != NULL)
1494 tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1495 newkey, key->keylen);
1496 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1497 }
1498 #endif
1499
1500 if (__inet_inherit_port(sk, newsk) < 0)
1501 goto put_and_exit;
1502 __inet_hash_nolisten(newsk, NULL);
1503
1504 return newsk;
1505
1506 exit_overflow:
1507 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1508 exit_nonewsk:
1509 dst_release(dst);
1510 exit:
1511 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1512 return NULL;
1513 put_and_exit:
1514 tcp_clear_xmit_timers(newsk);
1515 tcp_cleanup_congestion_control(newsk);
1516 bh_unlock_sock(newsk);
1517 sock_put(newsk);
1518 goto exit;
1519 }
1520 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1521
1522 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1523 {
1524 struct tcphdr *th = tcp_hdr(skb);
1525 const struct iphdr *iph = ip_hdr(skb);
1526 struct sock *nsk;
1527 struct request_sock **prev;
1528 /* Find possible connection requests. */
1529 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1530 iph->saddr, iph->daddr);
1531 if (req)
1532 return tcp_check_req(sk, skb, req, prev);
1533
1534 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1535 th->source, iph->daddr, th->dest, inet_iif(skb));
1536
1537 if (nsk) {
1538 if (nsk->sk_state != TCP_TIME_WAIT) {
1539 bh_lock_sock(nsk);
1540 return nsk;
1541 }
1542 inet_twsk_put(inet_twsk(nsk));
1543 return NULL;
1544 }
1545
1546 #ifdef CONFIG_SYN_COOKIES
1547 if (!th->syn)
1548 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1549 #endif
1550 return sk;
1551 }
1552
1553 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1554 {
1555 const struct iphdr *iph = ip_hdr(skb);
1556
1557 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1558 if (!tcp_v4_check(skb->len, iph->saddr,
1559 iph->daddr, skb->csum)) {
1560 skb->ip_summed = CHECKSUM_UNNECESSARY;
1561 return 0;
1562 }
1563 }
1564
1565 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1566 skb->len, IPPROTO_TCP, 0);
1567
1568 if (skb->len <= 76) {
1569 return __skb_checksum_complete(skb);
1570 }
1571 return 0;
1572 }
1573
1574
1575 /* The socket must have it's spinlock held when we get
1576 * here.
1577 *
1578 * We have a potential double-lock case here, so even when
1579 * doing backlog processing we use the BH locking scheme.
1580 * This is because we cannot sleep with the original spinlock
1581 * held.
1582 */
1583 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1584 {
1585 struct sock *rsk;
1586 #ifdef CONFIG_TCP_MD5SIG
1587 /*
1588 * We really want to reject the packet as early as possible
1589 * if:
1590 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1591 * o There is an MD5 option and we're not expecting one
1592 */
1593 if (tcp_v4_inbound_md5_hash(sk, skb))
1594 goto discard;
1595 #endif
1596
1597 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1598 sock_rps_save_rxhash(sk, skb);
1599 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1600 rsk = sk;
1601 goto reset;
1602 }
1603 return 0;
1604 }
1605
1606 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1607 goto csum_err;
1608
1609 if (sk->sk_state == TCP_LISTEN) {
1610 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1611 if (!nsk)
1612 goto discard;
1613
1614 if (nsk != sk) {
1615 sock_rps_save_rxhash(nsk, skb);
1616 if (tcp_child_process(sk, nsk, skb)) {
1617 rsk = nsk;
1618 goto reset;
1619 }
1620 return 0;
1621 }
1622 } else
1623 sock_rps_save_rxhash(sk, skb);
1624
1625 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1626 rsk = sk;
1627 goto reset;
1628 }
1629 return 0;
1630
1631 reset:
1632 tcp_v4_send_reset(rsk, skb);
1633 discard:
1634 kfree_skb(skb);
1635 /* Be careful here. If this function gets more complicated and
1636 * gcc suffers from register pressure on the x86, sk (in %ebx)
1637 * might be destroyed here. This current version compiles correctly,
1638 * but you have been warned.
1639 */
1640 return 0;
1641
1642 csum_err:
1643 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1644 goto discard;
1645 }
1646 EXPORT_SYMBOL(tcp_v4_do_rcv);
1647
1648 /*
1649 * From tcp_input.c
1650 */
1651
1652 int tcp_v4_rcv(struct sk_buff *skb)
1653 {
1654 const struct iphdr *iph;
1655 const struct tcphdr *th;
1656 struct sock *sk;
1657 int ret;
1658 struct net *net = dev_net(skb->dev);
1659
1660 if (skb->pkt_type != PACKET_HOST)
1661 goto discard_it;
1662
1663 /* Count it even if it's bad */
1664 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1665
1666 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1667 goto discard_it;
1668
1669 th = tcp_hdr(skb);
1670
1671 if (th->doff < sizeof(struct tcphdr) / 4)
1672 goto bad_packet;
1673 if (!pskb_may_pull(skb, th->doff * 4))
1674 goto discard_it;
1675
1676 /* An explanation is required here, I think.
1677 * Packet length and doff are validated by header prediction,
1678 * provided case of th->doff==0 is eliminated.
1679 * So, we defer the checks. */
1680 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1681 goto bad_packet;
1682
1683 th = tcp_hdr(skb);
1684 iph = ip_hdr(skb);
1685 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1686 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1687 skb->len - th->doff * 4);
1688 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1689 TCP_SKB_CB(skb)->when = 0;
1690 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1691 TCP_SKB_CB(skb)->sacked = 0;
1692
1693 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1694 if (!sk)
1695 goto no_tcp_socket;
1696
1697 process:
1698 if (sk->sk_state == TCP_TIME_WAIT)
1699 goto do_time_wait;
1700
1701 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1702 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1703 goto discard_and_relse;
1704 }
1705
1706 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1707 goto discard_and_relse;
1708 nf_reset(skb);
1709
1710 if (sk_filter(sk, skb))
1711 goto discard_and_relse;
1712
1713 skb->dev = NULL;
1714
1715 bh_lock_sock_nested(sk);
1716 ret = 0;
1717 if (!sock_owned_by_user(sk)) {
1718 #ifdef CONFIG_NET_DMA
1719 struct tcp_sock *tp = tcp_sk(sk);
1720 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1721 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1722 if (tp->ucopy.dma_chan)
1723 ret = tcp_v4_do_rcv(sk, skb);
1724 else
1725 #endif
1726 {
1727 if (!tcp_prequeue(sk, skb))
1728 ret = tcp_v4_do_rcv(sk, skb);
1729 }
1730 } else if (unlikely(sk_add_backlog(sk, skb))) {
1731 bh_unlock_sock(sk);
1732 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1733 goto discard_and_relse;
1734 }
1735 bh_unlock_sock(sk);
1736
1737 sock_put(sk);
1738
1739 return ret;
1740
1741 no_tcp_socket:
1742 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1743 goto discard_it;
1744
1745 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1746 bad_packet:
1747 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1748 } else {
1749 tcp_v4_send_reset(NULL, skb);
1750 }
1751
1752 discard_it:
1753 /* Discard frame. */
1754 kfree_skb(skb);
1755 return 0;
1756
1757 discard_and_relse:
1758 sock_put(sk);
1759 goto discard_it;
1760
1761 do_time_wait:
1762 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1763 inet_twsk_put(inet_twsk(sk));
1764 goto discard_it;
1765 }
1766
1767 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1768 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1769 inet_twsk_put(inet_twsk(sk));
1770 goto discard_it;
1771 }
1772 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1773 case TCP_TW_SYN: {
1774 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1775 &tcp_hashinfo,
1776 iph->daddr, th->dest,
1777 inet_iif(skb));
1778 if (sk2) {
1779 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1780 inet_twsk_put(inet_twsk(sk));
1781 sk = sk2;
1782 goto process;
1783 }
1784 /* Fall through to ACK */
1785 }
1786 case TCP_TW_ACK:
1787 tcp_v4_timewait_ack(sk, skb);
1788 break;
1789 case TCP_TW_RST:
1790 goto no_tcp_socket;
1791 case TCP_TW_SUCCESS:;
1792 }
1793 goto discard_it;
1794 }
1795
1796 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1797 {
1798 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1799 struct inet_sock *inet = inet_sk(sk);
1800 struct inet_peer *peer;
1801
1802 if (!rt ||
1803 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1804 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1805 *release_it = true;
1806 } else {
1807 if (!rt->peer)
1808 rt_bind_peer(rt, inet->inet_daddr, 1);
1809 peer = rt->peer;
1810 *release_it = false;
1811 }
1812
1813 return peer;
1814 }
1815 EXPORT_SYMBOL(tcp_v4_get_peer);
1816
1817 void *tcp_v4_tw_get_peer(struct sock *sk)
1818 {
1819 const struct inet_timewait_sock *tw = inet_twsk(sk);
1820
1821 return inet_getpeer_v4(tw->tw_daddr, 1);
1822 }
1823 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1824
1825 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1826 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1827 .twsk_unique = tcp_twsk_unique,
1828 .twsk_destructor= tcp_twsk_destructor,
1829 .twsk_getpeer = tcp_v4_tw_get_peer,
1830 };
1831
1832 const struct inet_connection_sock_af_ops ipv4_specific = {
1833 .queue_xmit = ip_queue_xmit,
1834 .send_check = tcp_v4_send_check,
1835 .rebuild_header = inet_sk_rebuild_header,
1836 .conn_request = tcp_v4_conn_request,
1837 .syn_recv_sock = tcp_v4_syn_recv_sock,
1838 .get_peer = tcp_v4_get_peer,
1839 .net_header_len = sizeof(struct iphdr),
1840 .setsockopt = ip_setsockopt,
1841 .getsockopt = ip_getsockopt,
1842 .addr2sockaddr = inet_csk_addr2sockaddr,
1843 .sockaddr_len = sizeof(struct sockaddr_in),
1844 .bind_conflict = inet_csk_bind_conflict,
1845 #ifdef CONFIG_COMPAT
1846 .compat_setsockopt = compat_ip_setsockopt,
1847 .compat_getsockopt = compat_ip_getsockopt,
1848 #endif
1849 };
1850 EXPORT_SYMBOL(ipv4_specific);
1851
1852 #ifdef CONFIG_TCP_MD5SIG
1853 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1854 .md5_lookup = tcp_v4_md5_lookup,
1855 .calc_md5_hash = tcp_v4_md5_hash_skb,
1856 .md5_add = tcp_v4_md5_add_func,
1857 .md5_parse = tcp_v4_parse_md5_keys,
1858 };
1859 #endif
1860
1861 /* NOTE: A lot of things set to zero explicitly by call to
1862 * sk_alloc() so need not be done here.
1863 */
1864 static int tcp_v4_init_sock(struct sock *sk)
1865 {
1866 struct inet_connection_sock *icsk = inet_csk(sk);
1867 struct tcp_sock *tp = tcp_sk(sk);
1868
1869 skb_queue_head_init(&tp->out_of_order_queue);
1870 tcp_init_xmit_timers(sk);
1871 tcp_prequeue_init(tp);
1872
1873 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1874 tp->mdev = TCP_TIMEOUT_INIT;
1875
1876 /* So many TCP implementations out there (incorrectly) count the
1877 * initial SYN frame in their delayed-ACK and congestion control
1878 * algorithms that we must have the following bandaid to talk
1879 * efficiently to them. -DaveM
1880 */
1881 tp->snd_cwnd = TCP_INIT_CWND;
1882
1883 /* See draft-stevens-tcpca-spec-01 for discussion of the
1884 * initialization of these values.
1885 */
1886 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1887 tp->snd_cwnd_clamp = ~0;
1888 tp->mss_cache = TCP_MSS_DEFAULT;
1889
1890 tp->reordering = sysctl_tcp_reordering;
1891 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1892
1893 sk->sk_state = TCP_CLOSE;
1894
1895 sk->sk_write_space = sk_stream_write_space;
1896 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1897
1898 icsk->icsk_af_ops = &ipv4_specific;
1899 icsk->icsk_sync_mss = tcp_sync_mss;
1900 #ifdef CONFIG_TCP_MD5SIG
1901 tp->af_specific = &tcp_sock_ipv4_specific;
1902 #endif
1903
1904 /* TCP Cookie Transactions */
1905 if (sysctl_tcp_cookie_size > 0) {
1906 /* Default, cookies without s_data_payload. */
1907 tp->cookie_values =
1908 kzalloc(sizeof(*tp->cookie_values),
1909 sk->sk_allocation);
1910 if (tp->cookie_values != NULL)
1911 kref_init(&tp->cookie_values->kref);
1912 }
1913 /* Presumed zeroed, in order of appearance:
1914 * cookie_in_always, cookie_out_never,
1915 * s_data_constant, s_data_in, s_data_out
1916 */
1917 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1918 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1919
1920 local_bh_disable();
1921 sock_update_memcg(sk);
1922 sk_sockets_allocated_inc(sk);
1923 local_bh_enable();
1924
1925 return 0;
1926 }
1927
1928 void tcp_v4_destroy_sock(struct sock *sk)
1929 {
1930 struct tcp_sock *tp = tcp_sk(sk);
1931
1932 tcp_clear_xmit_timers(sk);
1933
1934 tcp_cleanup_congestion_control(sk);
1935
1936 /* Cleanup up the write buffer. */
1937 tcp_write_queue_purge(sk);
1938
1939 /* Cleans up our, hopefully empty, out_of_order_queue. */
1940 __skb_queue_purge(&tp->out_of_order_queue);
1941
1942 #ifdef CONFIG_TCP_MD5SIG
1943 /* Clean up the MD5 key list, if any */
1944 if (tp->md5sig_info) {
1945 tcp_v4_clear_md5_list(sk);
1946 kfree(tp->md5sig_info);
1947 tp->md5sig_info = NULL;
1948 }
1949 #endif
1950
1951 #ifdef CONFIG_NET_DMA
1952 /* Cleans up our sk_async_wait_queue */
1953 __skb_queue_purge(&sk->sk_async_wait_queue);
1954 #endif
1955
1956 /* Clean prequeue, it must be empty really */
1957 __skb_queue_purge(&tp->ucopy.prequeue);
1958
1959 /* Clean up a referenced TCP bind bucket. */
1960 if (inet_csk(sk)->icsk_bind_hash)
1961 inet_put_port(sk);
1962
1963 /*
1964 * If sendmsg cached page exists, toss it.
1965 */
1966 if (sk->sk_sndmsg_page) {
1967 __free_page(sk->sk_sndmsg_page);
1968 sk->sk_sndmsg_page = NULL;
1969 }
1970
1971 /* TCP Cookie Transactions */
1972 if (tp->cookie_values != NULL) {
1973 kref_put(&tp->cookie_values->kref,
1974 tcp_cookie_values_release);
1975 tp->cookie_values = NULL;
1976 }
1977
1978 sk_sockets_allocated_dec(sk);
1979 sock_release_memcg(sk);
1980 }
1981 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1982
1983 #ifdef CONFIG_PROC_FS
1984 /* Proc filesystem TCP sock list dumping. */
1985
1986 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1987 {
1988 return hlist_nulls_empty(head) ? NULL :
1989 list_entry(head->first, struct inet_timewait_sock, tw_node);
1990 }
1991
1992 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1993 {
1994 return !is_a_nulls(tw->tw_node.next) ?
1995 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1996 }
1997
1998 /*
1999 * Get next listener socket follow cur. If cur is NULL, get first socket
2000 * starting from bucket given in st->bucket; when st->bucket is zero the
2001 * very first socket in the hash table is returned.
2002 */
2003 static void *listening_get_next(struct seq_file *seq, void *cur)
2004 {
2005 struct inet_connection_sock *icsk;
2006 struct hlist_nulls_node *node;
2007 struct sock *sk = cur;
2008 struct inet_listen_hashbucket *ilb;
2009 struct tcp_iter_state *st = seq->private;
2010 struct net *net = seq_file_net(seq);
2011
2012 if (!sk) {
2013 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2014 spin_lock_bh(&ilb->lock);
2015 sk = sk_nulls_head(&ilb->head);
2016 st->offset = 0;
2017 goto get_sk;
2018 }
2019 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2020 ++st->num;
2021 ++st->offset;
2022
2023 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2024 struct request_sock *req = cur;
2025
2026 icsk = inet_csk(st->syn_wait_sk);
2027 req = req->dl_next;
2028 while (1) {
2029 while (req) {
2030 if (req->rsk_ops->family == st->family) {
2031 cur = req;
2032 goto out;
2033 }
2034 req = req->dl_next;
2035 }
2036 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2037 break;
2038 get_req:
2039 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2040 }
2041 sk = sk_nulls_next(st->syn_wait_sk);
2042 st->state = TCP_SEQ_STATE_LISTENING;
2043 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2044 } else {
2045 icsk = inet_csk(sk);
2046 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2047 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2048 goto start_req;
2049 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2050 sk = sk_nulls_next(sk);
2051 }
2052 get_sk:
2053 sk_nulls_for_each_from(sk, node) {
2054 if (!net_eq(sock_net(sk), net))
2055 continue;
2056 if (sk->sk_family == st->family) {
2057 cur = sk;
2058 goto out;
2059 }
2060 icsk = inet_csk(sk);
2061 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2062 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2063 start_req:
2064 st->uid = sock_i_uid(sk);
2065 st->syn_wait_sk = sk;
2066 st->state = TCP_SEQ_STATE_OPENREQ;
2067 st->sbucket = 0;
2068 goto get_req;
2069 }
2070 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2071 }
2072 spin_unlock_bh(&ilb->lock);
2073 st->offset = 0;
2074 if (++st->bucket < INET_LHTABLE_SIZE) {
2075 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2076 spin_lock_bh(&ilb->lock);
2077 sk = sk_nulls_head(&ilb->head);
2078 goto get_sk;
2079 }
2080 cur = NULL;
2081 out:
2082 return cur;
2083 }
2084
2085 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2086 {
2087 struct tcp_iter_state *st = seq->private;
2088 void *rc;
2089
2090 st->bucket = 0;
2091 st->offset = 0;
2092 rc = listening_get_next(seq, NULL);
2093
2094 while (rc && *pos) {
2095 rc = listening_get_next(seq, rc);
2096 --*pos;
2097 }
2098 return rc;
2099 }
2100
2101 static inline int empty_bucket(struct tcp_iter_state *st)
2102 {
2103 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2104 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2105 }
2106
2107 /*
2108 * Get first established socket starting from bucket given in st->bucket.
2109 * If st->bucket is zero, the very first socket in the hash is returned.
2110 */
2111 static void *established_get_first(struct seq_file *seq)
2112 {
2113 struct tcp_iter_state *st = seq->private;
2114 struct net *net = seq_file_net(seq);
2115 void *rc = NULL;
2116
2117 st->offset = 0;
2118 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2119 struct sock *sk;
2120 struct hlist_nulls_node *node;
2121 struct inet_timewait_sock *tw;
2122 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2123
2124 /* Lockless fast path for the common case of empty buckets */
2125 if (empty_bucket(st))
2126 continue;
2127
2128 spin_lock_bh(lock);
2129 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2130 if (sk->sk_family != st->family ||
2131 !net_eq(sock_net(sk), net)) {
2132 continue;
2133 }
2134 rc = sk;
2135 goto out;
2136 }
2137 st->state = TCP_SEQ_STATE_TIME_WAIT;
2138 inet_twsk_for_each(tw, node,
2139 &tcp_hashinfo.ehash[st->bucket].twchain) {
2140 if (tw->tw_family != st->family ||
2141 !net_eq(twsk_net(tw), net)) {
2142 continue;
2143 }
2144 rc = tw;
2145 goto out;
2146 }
2147 spin_unlock_bh(lock);
2148 st->state = TCP_SEQ_STATE_ESTABLISHED;
2149 }
2150 out:
2151 return rc;
2152 }
2153
2154 static void *established_get_next(struct seq_file *seq, void *cur)
2155 {
2156 struct sock *sk = cur;
2157 struct inet_timewait_sock *tw;
2158 struct hlist_nulls_node *node;
2159 struct tcp_iter_state *st = seq->private;
2160 struct net *net = seq_file_net(seq);
2161
2162 ++st->num;
2163 ++st->offset;
2164
2165 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2166 tw = cur;
2167 tw = tw_next(tw);
2168 get_tw:
2169 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2170 tw = tw_next(tw);
2171 }
2172 if (tw) {
2173 cur = tw;
2174 goto out;
2175 }
2176 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2177 st->state = TCP_SEQ_STATE_ESTABLISHED;
2178
2179 /* Look for next non empty bucket */
2180 st->offset = 0;
2181 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2182 empty_bucket(st))
2183 ;
2184 if (st->bucket > tcp_hashinfo.ehash_mask)
2185 return NULL;
2186
2187 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2188 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2189 } else
2190 sk = sk_nulls_next(sk);
2191
2192 sk_nulls_for_each_from(sk, node) {
2193 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2194 goto found;
2195 }
2196
2197 st->state = TCP_SEQ_STATE_TIME_WAIT;
2198 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2199 goto get_tw;
2200 found:
2201 cur = sk;
2202 out:
2203 return cur;
2204 }
2205
2206 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2207 {
2208 struct tcp_iter_state *st = seq->private;
2209 void *rc;
2210
2211 st->bucket = 0;
2212 rc = established_get_first(seq);
2213
2214 while (rc && pos) {
2215 rc = established_get_next(seq, rc);
2216 --pos;
2217 }
2218 return rc;
2219 }
2220
2221 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2222 {
2223 void *rc;
2224 struct tcp_iter_state *st = seq->private;
2225
2226 st->state = TCP_SEQ_STATE_LISTENING;
2227 rc = listening_get_idx(seq, &pos);
2228
2229 if (!rc) {
2230 st->state = TCP_SEQ_STATE_ESTABLISHED;
2231 rc = established_get_idx(seq, pos);
2232 }
2233
2234 return rc;
2235 }
2236
2237 static void *tcp_seek_last_pos(struct seq_file *seq)
2238 {
2239 struct tcp_iter_state *st = seq->private;
2240 int offset = st->offset;
2241 int orig_num = st->num;
2242 void *rc = NULL;
2243
2244 switch (st->state) {
2245 case TCP_SEQ_STATE_OPENREQ:
2246 case TCP_SEQ_STATE_LISTENING:
2247 if (st->bucket >= INET_LHTABLE_SIZE)
2248 break;
2249 st->state = TCP_SEQ_STATE_LISTENING;
2250 rc = listening_get_next(seq, NULL);
2251 while (offset-- && rc)
2252 rc = listening_get_next(seq, rc);
2253 if (rc)
2254 break;
2255 st->bucket = 0;
2256 /* Fallthrough */
2257 case TCP_SEQ_STATE_ESTABLISHED:
2258 case TCP_SEQ_STATE_TIME_WAIT:
2259 st->state = TCP_SEQ_STATE_ESTABLISHED;
2260 if (st->bucket > tcp_hashinfo.ehash_mask)
2261 break;
2262 rc = established_get_first(seq);
2263 while (offset-- && rc)
2264 rc = established_get_next(seq, rc);
2265 }
2266
2267 st->num = orig_num;
2268
2269 return rc;
2270 }
2271
2272 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2273 {
2274 struct tcp_iter_state *st = seq->private;
2275 void *rc;
2276
2277 if (*pos && *pos == st->last_pos) {
2278 rc = tcp_seek_last_pos(seq);
2279 if (rc)
2280 goto out;
2281 }
2282
2283 st->state = TCP_SEQ_STATE_LISTENING;
2284 st->num = 0;
2285 st->bucket = 0;
2286 st->offset = 0;
2287 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2288
2289 out:
2290 st->last_pos = *pos;
2291 return rc;
2292 }
2293
2294 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2295 {
2296 struct tcp_iter_state *st = seq->private;
2297 void *rc = NULL;
2298
2299 if (v == SEQ_START_TOKEN) {
2300 rc = tcp_get_idx(seq, 0);
2301 goto out;
2302 }
2303
2304 switch (st->state) {
2305 case TCP_SEQ_STATE_OPENREQ:
2306 case TCP_SEQ_STATE_LISTENING:
2307 rc = listening_get_next(seq, v);
2308 if (!rc) {
2309 st->state = TCP_SEQ_STATE_ESTABLISHED;
2310 st->bucket = 0;
2311 st->offset = 0;
2312 rc = established_get_first(seq);
2313 }
2314 break;
2315 case TCP_SEQ_STATE_ESTABLISHED:
2316 case TCP_SEQ_STATE_TIME_WAIT:
2317 rc = established_get_next(seq, v);
2318 break;
2319 }
2320 out:
2321 ++*pos;
2322 st->last_pos = *pos;
2323 return rc;
2324 }
2325
2326 static void tcp_seq_stop(struct seq_file *seq, void *v)
2327 {
2328 struct tcp_iter_state *st = seq->private;
2329
2330 switch (st->state) {
2331 case TCP_SEQ_STATE_OPENREQ:
2332 if (v) {
2333 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2334 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2335 }
2336 case TCP_SEQ_STATE_LISTENING:
2337 if (v != SEQ_START_TOKEN)
2338 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2339 break;
2340 case TCP_SEQ_STATE_TIME_WAIT:
2341 case TCP_SEQ_STATE_ESTABLISHED:
2342 if (v)
2343 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2344 break;
2345 }
2346 }
2347
2348 int tcp_seq_open(struct inode *inode, struct file *file)
2349 {
2350 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2351 struct tcp_iter_state *s;
2352 int err;
2353
2354 err = seq_open_net(inode, file, &afinfo->seq_ops,
2355 sizeof(struct tcp_iter_state));
2356 if (err < 0)
2357 return err;
2358
2359 s = ((struct seq_file *)file->private_data)->private;
2360 s->family = afinfo->family;
2361 s->last_pos = 0;
2362 return 0;
2363 }
2364 EXPORT_SYMBOL(tcp_seq_open);
2365
2366 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2367 {
2368 int rc = 0;
2369 struct proc_dir_entry *p;
2370
2371 afinfo->seq_ops.start = tcp_seq_start;
2372 afinfo->seq_ops.next = tcp_seq_next;
2373 afinfo->seq_ops.stop = tcp_seq_stop;
2374
2375 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2376 afinfo->seq_fops, afinfo);
2377 if (!p)
2378 rc = -ENOMEM;
2379 return rc;
2380 }
2381 EXPORT_SYMBOL(tcp_proc_register);
2382
2383 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2384 {
2385 proc_net_remove(net, afinfo->name);
2386 }
2387 EXPORT_SYMBOL(tcp_proc_unregister);
2388
2389 static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2390 struct seq_file *f, int i, int uid, int *len)
2391 {
2392 const struct inet_request_sock *ireq = inet_rsk(req);
2393 int ttd = req->expires - jiffies;
2394
2395 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2396 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2397 i,
2398 ireq->loc_addr,
2399 ntohs(inet_sk(sk)->inet_sport),
2400 ireq->rmt_addr,
2401 ntohs(ireq->rmt_port),
2402 TCP_SYN_RECV,
2403 0, 0, /* could print option size, but that is af dependent. */
2404 1, /* timers active (only the expire timer) */
2405 jiffies_to_clock_t(ttd),
2406 req->retrans,
2407 uid,
2408 0, /* non standard timer */
2409 0, /* open_requests have no inode */
2410 atomic_read(&sk->sk_refcnt),
2411 req,
2412 len);
2413 }
2414
2415 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2416 {
2417 int timer_active;
2418 unsigned long timer_expires;
2419 const struct tcp_sock *tp = tcp_sk(sk);
2420 const struct inet_connection_sock *icsk = inet_csk(sk);
2421 const struct inet_sock *inet = inet_sk(sk);
2422 __be32 dest = inet->inet_daddr;
2423 __be32 src = inet->inet_rcv_saddr;
2424 __u16 destp = ntohs(inet->inet_dport);
2425 __u16 srcp = ntohs(inet->inet_sport);
2426 int rx_queue;
2427
2428 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2429 timer_active = 1;
2430 timer_expires = icsk->icsk_timeout;
2431 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2432 timer_active = 4;
2433 timer_expires = icsk->icsk_timeout;
2434 } else if (timer_pending(&sk->sk_timer)) {
2435 timer_active = 2;
2436 timer_expires = sk->sk_timer.expires;
2437 } else {
2438 timer_active = 0;
2439 timer_expires = jiffies;
2440 }
2441
2442 if (sk->sk_state == TCP_LISTEN)
2443 rx_queue = sk->sk_ack_backlog;
2444 else
2445 /*
2446 * because we dont lock socket, we might find a transient negative value
2447 */
2448 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2449
2450 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2451 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2452 i, src, srcp, dest, destp, sk->sk_state,
2453 tp->write_seq - tp->snd_una,
2454 rx_queue,
2455 timer_active,
2456 jiffies_to_clock_t(timer_expires - jiffies),
2457 icsk->icsk_retransmits,
2458 sock_i_uid(sk),
2459 icsk->icsk_probes_out,
2460 sock_i_ino(sk),
2461 atomic_read(&sk->sk_refcnt), sk,
2462 jiffies_to_clock_t(icsk->icsk_rto),
2463 jiffies_to_clock_t(icsk->icsk_ack.ato),
2464 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2465 tp->snd_cwnd,
2466 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2467 len);
2468 }
2469
2470 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2471 struct seq_file *f, int i, int *len)
2472 {
2473 __be32 dest, src;
2474 __u16 destp, srcp;
2475 int ttd = tw->tw_ttd - jiffies;
2476
2477 if (ttd < 0)
2478 ttd = 0;
2479
2480 dest = tw->tw_daddr;
2481 src = tw->tw_rcv_saddr;
2482 destp = ntohs(tw->tw_dport);
2483 srcp = ntohs(tw->tw_sport);
2484
2485 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2486 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2487 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2488 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2489 atomic_read(&tw->tw_refcnt), tw, len);
2490 }
2491
2492 #define TMPSZ 150
2493
2494 static int tcp4_seq_show(struct seq_file *seq, void *v)
2495 {
2496 struct tcp_iter_state *st;
2497 int len;
2498
2499 if (v == SEQ_START_TOKEN) {
2500 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2501 " sl local_address rem_address st tx_queue "
2502 "rx_queue tr tm->when retrnsmt uid timeout "
2503 "inode");
2504 goto out;
2505 }
2506 st = seq->private;
2507
2508 switch (st->state) {
2509 case TCP_SEQ_STATE_LISTENING:
2510 case TCP_SEQ_STATE_ESTABLISHED:
2511 get_tcp4_sock(v, seq, st->num, &len);
2512 break;
2513 case TCP_SEQ_STATE_OPENREQ:
2514 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2515 break;
2516 case TCP_SEQ_STATE_TIME_WAIT:
2517 get_timewait4_sock(v, seq, st->num, &len);
2518 break;
2519 }
2520 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2521 out:
2522 return 0;
2523 }
2524
2525 static const struct file_operations tcp_afinfo_seq_fops = {
2526 .owner = THIS_MODULE,
2527 .open = tcp_seq_open,
2528 .read = seq_read,
2529 .llseek = seq_lseek,
2530 .release = seq_release_net
2531 };
2532
2533 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2534 .name = "tcp",
2535 .family = AF_INET,
2536 .seq_fops = &tcp_afinfo_seq_fops,
2537 .seq_ops = {
2538 .show = tcp4_seq_show,
2539 },
2540 };
2541
2542 static int __net_init tcp4_proc_init_net(struct net *net)
2543 {
2544 return tcp_proc_register(net, &tcp4_seq_afinfo);
2545 }
2546
2547 static void __net_exit tcp4_proc_exit_net(struct net *net)
2548 {
2549 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2550 }
2551
2552 static struct pernet_operations tcp4_net_ops = {
2553 .init = tcp4_proc_init_net,
2554 .exit = tcp4_proc_exit_net,
2555 };
2556
2557 int __init tcp4_proc_init(void)
2558 {
2559 return register_pernet_subsys(&tcp4_net_ops);
2560 }
2561
2562 void tcp4_proc_exit(void)
2563 {
2564 unregister_pernet_subsys(&tcp4_net_ops);
2565 }
2566 #endif /* CONFIG_PROC_FS */
2567
2568 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2569 {
2570 const struct iphdr *iph = skb_gro_network_header(skb);
2571
2572 switch (skb->ip_summed) {
2573 case CHECKSUM_COMPLETE:
2574 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2575 skb->csum)) {
2576 skb->ip_summed = CHECKSUM_UNNECESSARY;
2577 break;
2578 }
2579
2580 /* fall through */
2581 case CHECKSUM_NONE:
2582 NAPI_GRO_CB(skb)->flush = 1;
2583 return NULL;
2584 }
2585
2586 return tcp_gro_receive(head, skb);
2587 }
2588
2589 int tcp4_gro_complete(struct sk_buff *skb)
2590 {
2591 const struct iphdr *iph = ip_hdr(skb);
2592 struct tcphdr *th = tcp_hdr(skb);
2593
2594 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2595 iph->saddr, iph->daddr, 0);
2596 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2597
2598 return tcp_gro_complete(skb);
2599 }
2600
2601 struct proto tcp_prot = {
2602 .name = "TCP",
2603 .owner = THIS_MODULE,
2604 .close = tcp_close,
2605 .connect = tcp_v4_connect,
2606 .disconnect = tcp_disconnect,
2607 .accept = inet_csk_accept,
2608 .ioctl = tcp_ioctl,
2609 .init = tcp_v4_init_sock,
2610 .destroy = tcp_v4_destroy_sock,
2611 .shutdown = tcp_shutdown,
2612 .setsockopt = tcp_setsockopt,
2613 .getsockopt = tcp_getsockopt,
2614 .recvmsg = tcp_recvmsg,
2615 .sendmsg = tcp_sendmsg,
2616 .sendpage = tcp_sendpage,
2617 .backlog_rcv = tcp_v4_do_rcv,
2618 .hash = inet_hash,
2619 .unhash = inet_unhash,
2620 .get_port = inet_csk_get_port,
2621 .enter_memory_pressure = tcp_enter_memory_pressure,
2622 .sockets_allocated = &tcp_sockets_allocated,
2623 .orphan_count = &tcp_orphan_count,
2624 .memory_allocated = &tcp_memory_allocated,
2625 .memory_pressure = &tcp_memory_pressure,
2626 .sysctl_wmem = sysctl_tcp_wmem,
2627 .sysctl_rmem = sysctl_tcp_rmem,
2628 .max_header = MAX_TCP_HEADER,
2629 .obj_size = sizeof(struct tcp_sock),
2630 .slab_flags = SLAB_DESTROY_BY_RCU,
2631 .twsk_prot = &tcp_timewait_sock_ops,
2632 .rsk_prot = &tcp_request_sock_ops,
2633 .h.hashinfo = &tcp_hashinfo,
2634 .no_autobind = true,
2635 #ifdef CONFIG_COMPAT
2636 .compat_setsockopt = compat_tcp_setsockopt,
2637 .compat_getsockopt = compat_tcp_getsockopt,
2638 #endif
2639 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2640 .init_cgroup = tcp_init_cgroup,
2641 .destroy_cgroup = tcp_destroy_cgroup,
2642 .proto_cgroup = tcp_proto_cgroup,
2643 #endif
2644 };
2645 EXPORT_SYMBOL(tcp_prot);
2646
2647 static int __net_init tcp_sk_init(struct net *net)
2648 {
2649 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2650 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2651 }
2652
2653 static void __net_exit tcp_sk_exit(struct net *net)
2654 {
2655 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2656 }
2657
2658 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2659 {
2660 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2661 }
2662
2663 static struct pernet_operations __net_initdata tcp_sk_ops = {
2664 .init = tcp_sk_init,
2665 .exit = tcp_sk_exit,
2666 .exit_batch = tcp_sk_exit_batch,
2667 };
2668
2669 void __init tcp_v4_init(void)
2670 {
2671 inet_hashinfo_init(&tcp_hashinfo);
2672 if (register_pernet_subsys(&tcp_sk_ops))
2673 panic("Failed to create the TCP control socket.\n");
2674 }
WandBoard kernel