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46e92fbd26a8fd01b9f989b7676206e2390567c2
[deliverable/linux.git] / net / ipv4 / tcp_ipv4.c
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 #define pr_fmt(fmt) "TCP: " fmt
54
55 #include <linux/bottom_half.h>
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64 #include <linux/slab.h>
65
66 #include <net/net_namespace.h>
67 #include <net/icmp.h>
68 #include <net/inet_hashtables.h>
69 #include <net/tcp.h>
70 #include <net/transp_v6.h>
71 #include <net/ipv6.h>
72 #include <net/inet_common.h>
73 #include <net/timewait_sock.h>
74 #include <net/xfrm.h>
75 #include <net/secure_seq.h>
76 #include <net/tcp_memcontrol.h>
77 #include <net/busy_poll.h>
78
79 #include <linux/inet.h>
80 #include <linux/ipv6.h>
81 #include <linux/stddef.h>
82 #include <linux/proc_fs.h>
83 #include <linux/seq_file.h>
84
85 #include <linux/crypto.h>
86 #include <linux/scatterlist.h>
87
88 int sysctl_tcp_tw_reuse __read_mostly;
89 int sysctl_tcp_low_latency __read_mostly;
90 EXPORT_SYMBOL(sysctl_tcp_low_latency);
91
92 #ifdef CONFIG_TCP_MD5SIG
93 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
94 __be32 daddr, __be32 saddr, const struct tcphdr *th);
95 #endif
96
97 struct inet_hashinfo tcp_hashinfo;
98 EXPORT_SYMBOL(tcp_hashinfo);
99
100 static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
101 {
102 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
103 ip_hdr(skb)->saddr,
104 tcp_hdr(skb)->dest,
105 tcp_hdr(skb)->source);
106 }
107
108 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
109 {
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112
113 /* With PAWS, it is safe from the viewpoint
114 of data integrity. Even without PAWS it is safe provided sequence
115 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
116
117 Actually, the idea is close to VJ's one, only timestamp cache is
118 held not per host, but per port pair and TW bucket is used as state
119 holder.
120
121 If TW bucket has been already destroyed we fall back to VJ's scheme
122 and use initial timestamp retrieved from peer table.
123 */
124 if (tcptw->tw_ts_recent_stamp &&
125 (!twp || (sysctl_tcp_tw_reuse &&
126 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
127 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
128 if (tp->write_seq == 0)
129 tp->write_seq = 1;
130 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
131 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
132 sock_hold(sktw);
133 return 1;
134 }
135
136 return 0;
137 }
138 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
139
140 /* This will initiate an outgoing connection. */
141 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
142 {
143 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
144 struct inet_sock *inet = inet_sk(sk);
145 struct tcp_sock *tp = tcp_sk(sk);
146 __be16 orig_sport, orig_dport;
147 __be32 daddr, nexthop;
148 struct flowi4 *fl4;
149 struct rtable *rt;
150 int err;
151 struct ip_options_rcu *inet_opt;
152
153 if (addr_len < sizeof(struct sockaddr_in))
154 return -EINVAL;
155
156 if (usin->sin_family != AF_INET)
157 return -EAFNOSUPPORT;
158
159 nexthop = daddr = usin->sin_addr.s_addr;
160 inet_opt = rcu_dereference_protected(inet->inet_opt,
161 sock_owned_by_user(sk));
162 if (inet_opt && inet_opt->opt.srr) {
163 if (!daddr)
164 return -EINVAL;
165 nexthop = inet_opt->opt.faddr;
166 }
167
168 orig_sport = inet->inet_sport;
169 orig_dport = usin->sin_port;
170 fl4 = &inet->cork.fl.u.ip4;
171 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
172 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
173 IPPROTO_TCP,
174 orig_sport, orig_dport, sk);
175 if (IS_ERR(rt)) {
176 err = PTR_ERR(rt);
177 if (err == -ENETUNREACH)
178 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
179 return err;
180 }
181
182 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
183 ip_rt_put(rt);
184 return -ENETUNREACH;
185 }
186
187 if (!inet_opt || !inet_opt->opt.srr)
188 daddr = fl4->daddr;
189
190 if (!inet->inet_saddr)
191 inet->inet_saddr = fl4->saddr;
192 sk_rcv_saddr_set(sk, inet->inet_saddr);
193
194 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
195 /* Reset inherited state */
196 tp->rx_opt.ts_recent = 0;
197 tp->rx_opt.ts_recent_stamp = 0;
198 if (likely(!tp->repair))
199 tp->write_seq = 0;
200 }
201
202 if (tcp_death_row.sysctl_tw_recycle &&
203 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
204 tcp_fetch_timewait_stamp(sk, &rt->dst);
205
206 inet->inet_dport = usin->sin_port;
207 sk_daddr_set(sk, daddr);
208
209 inet_csk(sk)->icsk_ext_hdr_len = 0;
210 if (inet_opt)
211 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
212
213 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
214
215 /* Socket identity is still unknown (sport may be zero).
216 * However we set state to SYN-SENT and not releasing socket
217 * lock select source port, enter ourselves into the hash tables and
218 * complete initialization after this.
219 */
220 tcp_set_state(sk, TCP_SYN_SENT);
221 err = inet_hash_connect(&tcp_death_row, sk);
222 if (err)
223 goto failure;
224
225 sk_set_txhash(sk);
226
227 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
228 inet->inet_sport, inet->inet_dport, sk);
229 if (IS_ERR(rt)) {
230 err = PTR_ERR(rt);
231 rt = NULL;
232 goto failure;
233 }
234 /* OK, now commit destination to socket. */
235 sk->sk_gso_type = SKB_GSO_TCPV4;
236 sk_setup_caps(sk, &rt->dst);
237
238 if (!tp->write_seq && likely(!tp->repair))
239 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
240 inet->inet_daddr,
241 inet->inet_sport,
242 usin->sin_port);
243
244 inet->inet_id = tp->write_seq ^ jiffies;
245
246 err = tcp_connect(sk);
247
248 rt = NULL;
249 if (err)
250 goto failure;
251
252 return 0;
253
254 failure:
255 /*
256 * This unhashes the socket and releases the local port,
257 * if necessary.
258 */
259 tcp_set_state(sk, TCP_CLOSE);
260 ip_rt_put(rt);
261 sk->sk_route_caps = 0;
262 inet->inet_dport = 0;
263 return err;
264 }
265 EXPORT_SYMBOL(tcp_v4_connect);
266
267 /*
268 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
269 * It can be called through tcp_release_cb() if socket was owned by user
270 * at the time tcp_v4_err() was called to handle ICMP message.
271 */
272 void tcp_v4_mtu_reduced(struct sock *sk)
273 {
274 struct dst_entry *dst;
275 struct inet_sock *inet = inet_sk(sk);
276 u32 mtu = tcp_sk(sk)->mtu_info;
277
278 dst = inet_csk_update_pmtu(sk, mtu);
279 if (!dst)
280 return;
281
282 /* Something is about to be wrong... Remember soft error
283 * for the case, if this connection will not able to recover.
284 */
285 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
286 sk->sk_err_soft = EMSGSIZE;
287
288 mtu = dst_mtu(dst);
289
290 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
291 ip_sk_accept_pmtu(sk) &&
292 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
293 tcp_sync_mss(sk, mtu);
294
295 /* Resend the TCP packet because it's
296 * clear that the old packet has been
297 * dropped. This is the new "fast" path mtu
298 * discovery.
299 */
300 tcp_simple_retransmit(sk);
301 } /* else let the usual retransmit timer handle it */
302 }
303 EXPORT_SYMBOL(tcp_v4_mtu_reduced);
304
305 static void do_redirect(struct sk_buff *skb, struct sock *sk)
306 {
307 struct dst_entry *dst = __sk_dst_check(sk, 0);
308
309 if (dst)
310 dst->ops->redirect(dst, sk, skb);
311 }
312
313
314 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
315 void tcp_req_err(struct sock *sk, u32 seq)
316 {
317 struct request_sock *req = inet_reqsk(sk);
318 struct net *net = sock_net(sk);
319
320 /* ICMPs are not backlogged, hence we cannot get
321 * an established socket here.
322 */
323 WARN_ON(req->sk);
324
325 if (seq != tcp_rsk(req)->snt_isn) {
326 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
327 } else {
328 /*
329 * Still in SYN_RECV, just remove it silently.
330 * There is no good way to pass the error to the newly
331 * created socket, and POSIX does not want network
332 * errors returned from accept().
333 */
334 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
335 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
336 }
337 reqsk_put(req);
338 }
339 EXPORT_SYMBOL(tcp_req_err);
340
341 /*
342 * This routine is called by the ICMP module when it gets some
343 * sort of error condition. If err < 0 then the socket should
344 * be closed and the error returned to the user. If err > 0
345 * it's just the icmp type << 8 | icmp code. After adjustment
346 * header points to the first 8 bytes of the tcp header. We need
347 * to find the appropriate port.
348 *
349 * The locking strategy used here is very "optimistic". When
350 * someone else accesses the socket the ICMP is just dropped
351 * and for some paths there is no check at all.
352 * A more general error queue to queue errors for later handling
353 * is probably better.
354 *
355 */
356
357 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
358 {
359 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
360 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
361 struct inet_connection_sock *icsk;
362 struct tcp_sock *tp;
363 struct inet_sock *inet;
364 const int type = icmp_hdr(icmp_skb)->type;
365 const int code = icmp_hdr(icmp_skb)->code;
366 struct sock *sk;
367 struct sk_buff *skb;
368 struct request_sock *fastopen;
369 __u32 seq, snd_una;
370 __u32 remaining;
371 int err;
372 struct net *net = dev_net(icmp_skb->dev);
373
374 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
375 th->dest, iph->saddr, ntohs(th->source),
376 inet_iif(icmp_skb));
377 if (!sk) {
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
379 return;
380 }
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
383 return;
384 }
385 seq = ntohl(th->seq);
386 if (sk->sk_state == TCP_NEW_SYN_RECV)
387 return tcp_req_err(sk, seq);
388
389 bh_lock_sock(sk);
390 /* If too many ICMPs get dropped on busy
391 * servers this needs to be solved differently.
392 * We do take care of PMTU discovery (RFC1191) special case :
393 * we can receive locally generated ICMP messages while socket is held.
394 */
395 if (sock_owned_by_user(sk)) {
396 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
397 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
398 }
399 if (sk->sk_state == TCP_CLOSE)
400 goto out;
401
402 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
403 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
404 goto out;
405 }
406
407 icsk = inet_csk(sk);
408 tp = tcp_sk(sk);
409 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
410 fastopen = tp->fastopen_rsk;
411 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
412 if (sk->sk_state != TCP_LISTEN &&
413 !between(seq, snd_una, tp->snd_nxt)) {
414 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
415 goto out;
416 }
417
418 switch (type) {
419 case ICMP_REDIRECT:
420 do_redirect(icmp_skb, sk);
421 goto out;
422 case ICMP_SOURCE_QUENCH:
423 /* Just silently ignore these. */
424 goto out;
425 case ICMP_PARAMETERPROB:
426 err = EPROTO;
427 break;
428 case ICMP_DEST_UNREACH:
429 if (code > NR_ICMP_UNREACH)
430 goto out;
431
432 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
433 /* We are not interested in TCP_LISTEN and open_requests
434 * (SYN-ACKs send out by Linux are always <576bytes so
435 * they should go through unfragmented).
436 */
437 if (sk->sk_state == TCP_LISTEN)
438 goto out;
439
440 tp->mtu_info = info;
441 if (!sock_owned_by_user(sk)) {
442 tcp_v4_mtu_reduced(sk);
443 } else {
444 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
445 sock_hold(sk);
446 }
447 goto out;
448 }
449
450 err = icmp_err_convert[code].errno;
451 /* check if icmp_skb allows revert of backoff
452 * (see draft-zimmermann-tcp-lcd) */
453 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
454 break;
455 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
456 !icsk->icsk_backoff || fastopen)
457 break;
458
459 if (sock_owned_by_user(sk))
460 break;
461
462 icsk->icsk_backoff--;
463 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
464 TCP_TIMEOUT_INIT;
465 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
466
467 skb = tcp_write_queue_head(sk);
468 BUG_ON(!skb);
469
470 remaining = icsk->icsk_rto -
471 min(icsk->icsk_rto,
472 tcp_time_stamp - tcp_skb_timestamp(skb));
473
474 if (remaining) {
475 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
476 remaining, TCP_RTO_MAX);
477 } else {
478 /* RTO revert clocked out retransmission.
479 * Will retransmit now */
480 tcp_retransmit_timer(sk);
481 }
482
483 break;
484 case ICMP_TIME_EXCEEDED:
485 err = EHOSTUNREACH;
486 break;
487 default:
488 goto out;
489 }
490
491 switch (sk->sk_state) {
492 case TCP_SYN_SENT:
493 case TCP_SYN_RECV:
494 /* Only in fast or simultaneous open. If a fast open socket is
495 * is already accepted it is treated as a connected one below.
496 */
497 if (fastopen && !fastopen->sk)
498 break;
499
500 if (!sock_owned_by_user(sk)) {
501 sk->sk_err = err;
502
503 sk->sk_error_report(sk);
504
505 tcp_done(sk);
506 } else {
507 sk->sk_err_soft = err;
508 }
509 goto out;
510 }
511
512 /* If we've already connected we will keep trying
513 * until we time out, or the user gives up.
514 *
515 * rfc1122 4.2.3.9 allows to consider as hard errors
516 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
517 * but it is obsoleted by pmtu discovery).
518 *
519 * Note, that in modern internet, where routing is unreliable
520 * and in each dark corner broken firewalls sit, sending random
521 * errors ordered by their masters even this two messages finally lose
522 * their original sense (even Linux sends invalid PORT_UNREACHs)
523 *
524 * Now we are in compliance with RFCs.
525 * --ANK (980905)
526 */
527
528 inet = inet_sk(sk);
529 if (!sock_owned_by_user(sk) && inet->recverr) {
530 sk->sk_err = err;
531 sk->sk_error_report(sk);
532 } else { /* Only an error on timeout */
533 sk->sk_err_soft = err;
534 }
535
536 out:
537 bh_unlock_sock(sk);
538 sock_put(sk);
539 }
540
541 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
542 {
543 struct tcphdr *th = tcp_hdr(skb);
544
545 if (skb->ip_summed == CHECKSUM_PARTIAL) {
546 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
547 skb->csum_start = skb_transport_header(skb) - skb->head;
548 skb->csum_offset = offsetof(struct tcphdr, check);
549 } else {
550 th->check = tcp_v4_check(skb->len, saddr, daddr,
551 csum_partial(th,
552 th->doff << 2,
553 skb->csum));
554 }
555 }
556
557 /* This routine computes an IPv4 TCP checksum. */
558 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
559 {
560 const struct inet_sock *inet = inet_sk(sk);
561
562 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
563 }
564 EXPORT_SYMBOL(tcp_v4_send_check);
565
566 /*
567 * This routine will send an RST to the other tcp.
568 *
569 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
570 * for reset.
571 * Answer: if a packet caused RST, it is not for a socket
572 * existing in our system, if it is matched to a socket,
573 * it is just duplicate segment or bug in other side's TCP.
574 * So that we build reply only basing on parameters
575 * arrived with segment.
576 * Exception: precedence violation. We do not implement it in any case.
577 */
578
579 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
580 {
581 const struct tcphdr *th = tcp_hdr(skb);
582 struct {
583 struct tcphdr th;
584 #ifdef CONFIG_TCP_MD5SIG
585 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
586 #endif
587 } rep;
588 struct ip_reply_arg arg;
589 #ifdef CONFIG_TCP_MD5SIG
590 struct tcp_md5sig_key *key;
591 const __u8 *hash_location = NULL;
592 unsigned char newhash[16];
593 int genhash;
594 struct sock *sk1 = NULL;
595 #endif
596 struct net *net;
597
598 /* Never send a reset in response to a reset. */
599 if (th->rst)
600 return;
601
602 /* If sk not NULL, it means we did a successful lookup and incoming
603 * route had to be correct. prequeue might have dropped our dst.
604 */
605 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
606 return;
607
608 /* Swap the send and the receive. */
609 memset(&rep, 0, sizeof(rep));
610 rep.th.dest = th->source;
611 rep.th.source = th->dest;
612 rep.th.doff = sizeof(struct tcphdr) / 4;
613 rep.th.rst = 1;
614
615 if (th->ack) {
616 rep.th.seq = th->ack_seq;
617 } else {
618 rep.th.ack = 1;
619 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
620 skb->len - (th->doff << 2));
621 }
622
623 memset(&arg, 0, sizeof(arg));
624 arg.iov[0].iov_base = (unsigned char *)&rep;
625 arg.iov[0].iov_len = sizeof(rep.th);
626
627 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
628 #ifdef CONFIG_TCP_MD5SIG
629 hash_location = tcp_parse_md5sig_option(th);
630 if (!sk && hash_location) {
631 /*
632 * active side is lost. Try to find listening socket through
633 * source port, and then find md5 key through listening socket.
634 * we are not loose security here:
635 * Incoming packet is checked with md5 hash with finding key,
636 * no RST generated if md5 hash doesn't match.
637 */
638 sk1 = __inet_lookup_listener(net,
639 &tcp_hashinfo, ip_hdr(skb)->saddr,
640 th->source, ip_hdr(skb)->daddr,
641 ntohs(th->source), inet_iif(skb));
642 /* don't send rst if it can't find key */
643 if (!sk1)
644 return;
645 rcu_read_lock();
646 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
647 &ip_hdr(skb)->saddr, AF_INET);
648 if (!key)
649 goto release_sk1;
650
651 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
652 if (genhash || memcmp(hash_location, newhash, 16) != 0)
653 goto release_sk1;
654 } else {
655 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
656 &ip_hdr(skb)->saddr,
657 AF_INET) : NULL;
658 }
659
660 if (key) {
661 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
662 (TCPOPT_NOP << 16) |
663 (TCPOPT_MD5SIG << 8) |
664 TCPOLEN_MD5SIG);
665 /* Update length and the length the header thinks exists */
666 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
667 rep.th.doff = arg.iov[0].iov_len / 4;
668
669 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
670 key, ip_hdr(skb)->saddr,
671 ip_hdr(skb)->daddr, &rep.th);
672 }
673 #endif
674 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
675 ip_hdr(skb)->saddr, /* XXX */
676 arg.iov[0].iov_len, IPPROTO_TCP, 0);
677 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
678 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
679 /* When socket is gone, all binding information is lost.
680 * routing might fail in this case. No choice here, if we choose to force
681 * input interface, we will misroute in case of asymmetric route.
682 */
683 if (sk)
684 arg.bound_dev_if = sk->sk_bound_dev_if;
685
686 arg.tos = ip_hdr(skb)->tos;
687 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
688 skb, &TCP_SKB_CB(skb)->header.h4.opt,
689 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
690 &arg, arg.iov[0].iov_len);
691
692 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
693 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
694
695 #ifdef CONFIG_TCP_MD5SIG
696 release_sk1:
697 if (sk1) {
698 rcu_read_unlock();
699 sock_put(sk1);
700 }
701 #endif
702 }
703
704 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
705 outside socket context is ugly, certainly. What can I do?
706 */
707
708 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
709 u32 win, u32 tsval, u32 tsecr, int oif,
710 struct tcp_md5sig_key *key,
711 int reply_flags, u8 tos)
712 {
713 const struct tcphdr *th = tcp_hdr(skb);
714 struct {
715 struct tcphdr th;
716 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
717 #ifdef CONFIG_TCP_MD5SIG
718 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
719 #endif
720 ];
721 } rep;
722 struct ip_reply_arg arg;
723 struct net *net = dev_net(skb_dst(skb)->dev);
724
725 memset(&rep.th, 0, sizeof(struct tcphdr));
726 memset(&arg, 0, sizeof(arg));
727
728 arg.iov[0].iov_base = (unsigned char *)&rep;
729 arg.iov[0].iov_len = sizeof(rep.th);
730 if (tsecr) {
731 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
732 (TCPOPT_TIMESTAMP << 8) |
733 TCPOLEN_TIMESTAMP);
734 rep.opt[1] = htonl(tsval);
735 rep.opt[2] = htonl(tsecr);
736 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
737 }
738
739 /* Swap the send and the receive. */
740 rep.th.dest = th->source;
741 rep.th.source = th->dest;
742 rep.th.doff = arg.iov[0].iov_len / 4;
743 rep.th.seq = htonl(seq);
744 rep.th.ack_seq = htonl(ack);
745 rep.th.ack = 1;
746 rep.th.window = htons(win);
747
748 #ifdef CONFIG_TCP_MD5SIG
749 if (key) {
750 int offset = (tsecr) ? 3 : 0;
751
752 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
753 (TCPOPT_NOP << 16) |
754 (TCPOPT_MD5SIG << 8) |
755 TCPOLEN_MD5SIG);
756 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
757 rep.th.doff = arg.iov[0].iov_len/4;
758
759 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
760 key, ip_hdr(skb)->saddr,
761 ip_hdr(skb)->daddr, &rep.th);
762 }
763 #endif
764 arg.flags = reply_flags;
765 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
766 ip_hdr(skb)->saddr, /* XXX */
767 arg.iov[0].iov_len, IPPROTO_TCP, 0);
768 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
769 if (oif)
770 arg.bound_dev_if = oif;
771 arg.tos = tos;
772 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
773 skb, &TCP_SKB_CB(skb)->header.h4.opt,
774 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
775 &arg, arg.iov[0].iov_len);
776
777 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
778 }
779
780 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
781 {
782 struct inet_timewait_sock *tw = inet_twsk(sk);
783 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
784
785 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
786 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
787 tcp_time_stamp + tcptw->tw_ts_offset,
788 tcptw->tw_ts_recent,
789 tw->tw_bound_dev_if,
790 tcp_twsk_md5_key(tcptw),
791 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
792 tw->tw_tos
793 );
794
795 inet_twsk_put(tw);
796 }
797
798 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
799 struct request_sock *req)
800 {
801 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
802 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
803 */
804 tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
805 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
806 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
807 tcp_time_stamp,
808 req->ts_recent,
809 0,
810 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
811 AF_INET),
812 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
813 ip_hdr(skb)->tos);
814 }
815
816 /*
817 * Send a SYN-ACK after having received a SYN.
818 * This still operates on a request_sock only, not on a big
819 * socket.
820 */
821 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
822 struct flowi *fl,
823 struct request_sock *req,
824 struct tcp_fastopen_cookie *foc,
825 bool attach_req)
826 {
827 const struct inet_request_sock *ireq = inet_rsk(req);
828 struct flowi4 fl4;
829 int err = -1;
830 struct sk_buff *skb;
831
832 /* First, grab a route. */
833 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
834 return -1;
835
836 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
837
838 if (skb) {
839 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
840
841 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
842 ireq->ir_rmt_addr,
843 ireq->opt);
844 err = net_xmit_eval(err);
845 }
846
847 return err;
848 }
849
850 /*
851 * IPv4 request_sock destructor.
852 */
853 static void tcp_v4_reqsk_destructor(struct request_sock *req)
854 {
855 kfree(inet_rsk(req)->opt);
856 }
857
858
859 #ifdef CONFIG_TCP_MD5SIG
860 /*
861 * RFC2385 MD5 checksumming requires a mapping of
862 * IP address->MD5 Key.
863 * We need to maintain these in the sk structure.
864 */
865
866 /* Find the Key structure for an address. */
867 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
868 const union tcp_md5_addr *addr,
869 int family)
870 {
871 const struct tcp_sock *tp = tcp_sk(sk);
872 struct tcp_md5sig_key *key;
873 unsigned int size = sizeof(struct in_addr);
874 const struct tcp_md5sig_info *md5sig;
875
876 /* caller either holds rcu_read_lock() or socket lock */
877 md5sig = rcu_dereference_check(tp->md5sig_info,
878 sock_owned_by_user(sk) ||
879 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
880 if (!md5sig)
881 return NULL;
882 #if IS_ENABLED(CONFIG_IPV6)
883 if (family == AF_INET6)
884 size = sizeof(struct in6_addr);
885 #endif
886 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
887 if (key->family != family)
888 continue;
889 if (!memcmp(&key->addr, addr, size))
890 return key;
891 }
892 return NULL;
893 }
894 EXPORT_SYMBOL(tcp_md5_do_lookup);
895
896 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
897 const struct sock *addr_sk)
898 {
899 const union tcp_md5_addr *addr;
900
901 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
902 return tcp_md5_do_lookup(sk, addr, AF_INET);
903 }
904 EXPORT_SYMBOL(tcp_v4_md5_lookup);
905
906 /* This can be called on a newly created socket, from other files */
907 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
908 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
909 {
910 /* Add Key to the list */
911 struct tcp_md5sig_key *key;
912 struct tcp_sock *tp = tcp_sk(sk);
913 struct tcp_md5sig_info *md5sig;
914
915 key = tcp_md5_do_lookup(sk, addr, family);
916 if (key) {
917 /* Pre-existing entry - just update that one. */
918 memcpy(key->key, newkey, newkeylen);
919 key->keylen = newkeylen;
920 return 0;
921 }
922
923 md5sig = rcu_dereference_protected(tp->md5sig_info,
924 sock_owned_by_user(sk) ||
925 lockdep_is_held(&sk->sk_lock.slock));
926 if (!md5sig) {
927 md5sig = kmalloc(sizeof(*md5sig), gfp);
928 if (!md5sig)
929 return -ENOMEM;
930
931 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
932 INIT_HLIST_HEAD(&md5sig->head);
933 rcu_assign_pointer(tp->md5sig_info, md5sig);
934 }
935
936 key = sock_kmalloc(sk, sizeof(*key), gfp);
937 if (!key)
938 return -ENOMEM;
939 if (!tcp_alloc_md5sig_pool()) {
940 sock_kfree_s(sk, key, sizeof(*key));
941 return -ENOMEM;
942 }
943
944 memcpy(key->key, newkey, newkeylen);
945 key->keylen = newkeylen;
946 key->family = family;
947 memcpy(&key->addr, addr,
948 (family == AF_INET6) ? sizeof(struct in6_addr) :
949 sizeof(struct in_addr));
950 hlist_add_head_rcu(&key->node, &md5sig->head);
951 return 0;
952 }
953 EXPORT_SYMBOL(tcp_md5_do_add);
954
955 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
956 {
957 struct tcp_md5sig_key *key;
958
959 key = tcp_md5_do_lookup(sk, addr, family);
960 if (!key)
961 return -ENOENT;
962 hlist_del_rcu(&key->node);
963 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
964 kfree_rcu(key, rcu);
965 return 0;
966 }
967 EXPORT_SYMBOL(tcp_md5_do_del);
968
969 static void tcp_clear_md5_list(struct sock *sk)
970 {
971 struct tcp_sock *tp = tcp_sk(sk);
972 struct tcp_md5sig_key *key;
973 struct hlist_node *n;
974 struct tcp_md5sig_info *md5sig;
975
976 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
977
978 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
979 hlist_del_rcu(&key->node);
980 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
981 kfree_rcu(key, rcu);
982 }
983 }
984
985 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
986 int optlen)
987 {
988 struct tcp_md5sig cmd;
989 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
990
991 if (optlen < sizeof(cmd))
992 return -EINVAL;
993
994 if (copy_from_user(&cmd, optval, sizeof(cmd)))
995 return -EFAULT;
996
997 if (sin->sin_family != AF_INET)
998 return -EINVAL;
999
1000 if (!cmd.tcpm_keylen)
1001 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1002 AF_INET);
1003
1004 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1005 return -EINVAL;
1006
1007 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1008 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1009 GFP_KERNEL);
1010 }
1011
1012 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1013 __be32 daddr, __be32 saddr, int nbytes)
1014 {
1015 struct tcp4_pseudohdr *bp;
1016 struct scatterlist sg;
1017
1018 bp = &hp->md5_blk.ip4;
1019
1020 /*
1021 * 1. the TCP pseudo-header (in the order: source IP address,
1022 * destination IP address, zero-padded protocol number, and
1023 * segment length)
1024 */
1025 bp->saddr = saddr;
1026 bp->daddr = daddr;
1027 bp->pad = 0;
1028 bp->protocol = IPPROTO_TCP;
1029 bp->len = cpu_to_be16(nbytes);
1030
1031 sg_init_one(&sg, bp, sizeof(*bp));
1032 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1033 }
1034
1035 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1036 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1037 {
1038 struct tcp_md5sig_pool *hp;
1039 struct hash_desc *desc;
1040
1041 hp = tcp_get_md5sig_pool();
1042 if (!hp)
1043 goto clear_hash_noput;
1044 desc = &hp->md5_desc;
1045
1046 if (crypto_hash_init(desc))
1047 goto clear_hash;
1048 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1049 goto clear_hash;
1050 if (tcp_md5_hash_header(hp, th))
1051 goto clear_hash;
1052 if (tcp_md5_hash_key(hp, key))
1053 goto clear_hash;
1054 if (crypto_hash_final(desc, md5_hash))
1055 goto clear_hash;
1056
1057 tcp_put_md5sig_pool();
1058 return 0;
1059
1060 clear_hash:
1061 tcp_put_md5sig_pool();
1062 clear_hash_noput:
1063 memset(md5_hash, 0, 16);
1064 return 1;
1065 }
1066
1067 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1068 const struct sock *sk,
1069 const struct sk_buff *skb)
1070 {
1071 struct tcp_md5sig_pool *hp;
1072 struct hash_desc *desc;
1073 const struct tcphdr *th = tcp_hdr(skb);
1074 __be32 saddr, daddr;
1075
1076 if (sk) { /* valid for establish/request sockets */
1077 saddr = sk->sk_rcv_saddr;
1078 daddr = sk->sk_daddr;
1079 } else {
1080 const struct iphdr *iph = ip_hdr(skb);
1081 saddr = iph->saddr;
1082 daddr = iph->daddr;
1083 }
1084
1085 hp = tcp_get_md5sig_pool();
1086 if (!hp)
1087 goto clear_hash_noput;
1088 desc = &hp->md5_desc;
1089
1090 if (crypto_hash_init(desc))
1091 goto clear_hash;
1092
1093 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1094 goto clear_hash;
1095 if (tcp_md5_hash_header(hp, th))
1096 goto clear_hash;
1097 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1098 goto clear_hash;
1099 if (tcp_md5_hash_key(hp, key))
1100 goto clear_hash;
1101 if (crypto_hash_final(desc, md5_hash))
1102 goto clear_hash;
1103
1104 tcp_put_md5sig_pool();
1105 return 0;
1106
1107 clear_hash:
1108 tcp_put_md5sig_pool();
1109 clear_hash_noput:
1110 memset(md5_hash, 0, 16);
1111 return 1;
1112 }
1113 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1114
1115 #endif
1116
1117 /* Called with rcu_read_lock() */
1118 static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1119 const struct sk_buff *skb)
1120 {
1121 #ifdef CONFIG_TCP_MD5SIG
1122 /*
1123 * This gets called for each TCP segment that arrives
1124 * so we want to be efficient.
1125 * We have 3 drop cases:
1126 * o No MD5 hash and one expected.
1127 * o MD5 hash and we're not expecting one.
1128 * o MD5 hash and its wrong.
1129 */
1130 const __u8 *hash_location = NULL;
1131 struct tcp_md5sig_key *hash_expected;
1132 const struct iphdr *iph = ip_hdr(skb);
1133 const struct tcphdr *th = tcp_hdr(skb);
1134 int genhash;
1135 unsigned char newhash[16];
1136
1137 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1138 AF_INET);
1139 hash_location = tcp_parse_md5sig_option(th);
1140
1141 /* We've parsed the options - do we have a hash? */
1142 if (!hash_expected && !hash_location)
1143 return false;
1144
1145 if (hash_expected && !hash_location) {
1146 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1147 return true;
1148 }
1149
1150 if (!hash_expected && hash_location) {
1151 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1152 return true;
1153 }
1154
1155 /* Okay, so this is hash_expected and hash_location -
1156 * so we need to calculate the checksum.
1157 */
1158 genhash = tcp_v4_md5_hash_skb(newhash,
1159 hash_expected,
1160 NULL, skb);
1161
1162 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1163 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1164 &iph->saddr, ntohs(th->source),
1165 &iph->daddr, ntohs(th->dest),
1166 genhash ? " tcp_v4_calc_md5_hash failed"
1167 : "");
1168 return true;
1169 }
1170 return false;
1171 #endif
1172 return false;
1173 }
1174
1175 static void tcp_v4_init_req(struct request_sock *req,
1176 const struct sock *sk_listener,
1177 struct sk_buff *skb)
1178 {
1179 struct inet_request_sock *ireq = inet_rsk(req);
1180
1181 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1182 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1183 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1184 ireq->opt = tcp_v4_save_options(skb);
1185 }
1186
1187 static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1188 struct flowi *fl,
1189 const struct request_sock *req,
1190 bool *strict)
1191 {
1192 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1193
1194 if (strict) {
1195 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1196 *strict = true;
1197 else
1198 *strict = false;
1199 }
1200
1201 return dst;
1202 }
1203
1204 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1205 .family = PF_INET,
1206 .obj_size = sizeof(struct tcp_request_sock),
1207 .rtx_syn_ack = tcp_rtx_synack,
1208 .send_ack = tcp_v4_reqsk_send_ack,
1209 .destructor = tcp_v4_reqsk_destructor,
1210 .send_reset = tcp_v4_send_reset,
1211 .syn_ack_timeout = tcp_syn_ack_timeout,
1212 };
1213
1214 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1215 .mss_clamp = TCP_MSS_DEFAULT,
1216 #ifdef CONFIG_TCP_MD5SIG
1217 .req_md5_lookup = tcp_v4_md5_lookup,
1218 .calc_md5_hash = tcp_v4_md5_hash_skb,
1219 #endif
1220 .init_req = tcp_v4_init_req,
1221 #ifdef CONFIG_SYN_COOKIES
1222 .cookie_init_seq = cookie_v4_init_sequence,
1223 #endif
1224 .route_req = tcp_v4_route_req,
1225 .init_seq = tcp_v4_init_sequence,
1226 .send_synack = tcp_v4_send_synack,
1227 };
1228
1229 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1230 {
1231 /* Never answer to SYNs send to broadcast or multicast */
1232 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1233 goto drop;
1234
1235 return tcp_conn_request(&tcp_request_sock_ops,
1236 &tcp_request_sock_ipv4_ops, sk, skb);
1237
1238 drop:
1239 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1240 return 0;
1241 }
1242 EXPORT_SYMBOL(tcp_v4_conn_request);
1243
1244
1245 /*
1246 * The three way handshake has completed - we got a valid synack -
1247 * now create the new socket.
1248 */
1249 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1250 struct request_sock *req,
1251 struct dst_entry *dst,
1252 struct request_sock *req_unhash,
1253 bool *own_req)
1254 {
1255 struct inet_request_sock *ireq;
1256 struct inet_sock *newinet;
1257 struct tcp_sock *newtp;
1258 struct sock *newsk;
1259 #ifdef CONFIG_TCP_MD5SIG
1260 struct tcp_md5sig_key *key;
1261 #endif
1262 struct ip_options_rcu *inet_opt;
1263
1264 if (sk_acceptq_is_full(sk))
1265 goto exit_overflow;
1266
1267 newsk = tcp_create_openreq_child(sk, req, skb);
1268 if (!newsk)
1269 goto exit_nonewsk;
1270
1271 newsk->sk_gso_type = SKB_GSO_TCPV4;
1272 inet_sk_rx_dst_set(newsk, skb);
1273
1274 newtp = tcp_sk(newsk);
1275 newinet = inet_sk(newsk);
1276 ireq = inet_rsk(req);
1277 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1278 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1279 newsk->sk_bound_dev_if = ireq->ir_iif;
1280 newinet->inet_saddr = ireq->ir_loc_addr;
1281 inet_opt = ireq->opt;
1282 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1283 ireq->opt = NULL;
1284 newinet->mc_index = inet_iif(skb);
1285 newinet->mc_ttl = ip_hdr(skb)->ttl;
1286 newinet->rcv_tos = ip_hdr(skb)->tos;
1287 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1288 if (inet_opt)
1289 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1290 newinet->inet_id = newtp->write_seq ^ jiffies;
1291
1292 if (!dst) {
1293 dst = inet_csk_route_child_sock(sk, newsk, req);
1294 if (!dst)
1295 goto put_and_exit;
1296 } else {
1297 /* syncookie case : see end of cookie_v4_check() */
1298 }
1299 sk_setup_caps(newsk, dst);
1300
1301 tcp_ca_openreq_child(newsk, dst);
1302
1303 tcp_sync_mss(newsk, dst_mtu(dst));
1304 newtp->advmss = dst_metric_advmss(dst);
1305 if (tcp_sk(sk)->rx_opt.user_mss &&
1306 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1307 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1308
1309 tcp_initialize_rcv_mss(newsk);
1310
1311 #ifdef CONFIG_TCP_MD5SIG
1312 /* Copy over the MD5 key from the original socket */
1313 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1314 AF_INET);
1315 if (key) {
1316 /*
1317 * We're using one, so create a matching key
1318 * on the newsk structure. If we fail to get
1319 * memory, then we end up not copying the key
1320 * across. Shucks.
1321 */
1322 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1323 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1324 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1325 }
1326 #endif
1327
1328 if (__inet_inherit_port(sk, newsk) < 0)
1329 goto put_and_exit;
1330 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1331 if (*own_req)
1332 tcp_move_syn(newtp, req);
1333
1334 return newsk;
1335
1336 exit_overflow:
1337 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1338 exit_nonewsk:
1339 dst_release(dst);
1340 exit:
1341 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1342 return NULL;
1343 put_and_exit:
1344 inet_csk_prepare_forced_close(newsk);
1345 tcp_done(newsk);
1346 goto exit;
1347 }
1348 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1349
1350 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1351 {
1352 #ifdef CONFIG_SYN_COOKIES
1353 const struct tcphdr *th = tcp_hdr(skb);
1354
1355 if (!th->syn)
1356 sk = cookie_v4_check(sk, skb);
1357 #endif
1358 return sk;
1359 }
1360
1361 /* The socket must have it's spinlock held when we get
1362 * here, unless it is a TCP_LISTEN socket.
1363 *
1364 * We have a potential double-lock case here, so even when
1365 * doing backlog processing we use the BH locking scheme.
1366 * This is because we cannot sleep with the original spinlock
1367 * held.
1368 */
1369 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1370 {
1371 struct sock *rsk;
1372
1373 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1374 struct dst_entry *dst = sk->sk_rx_dst;
1375
1376 sock_rps_save_rxhash(sk, skb);
1377 sk_mark_napi_id(sk, skb);
1378 if (dst) {
1379 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1380 !dst->ops->check(dst, 0)) {
1381 dst_release(dst);
1382 sk->sk_rx_dst = NULL;
1383 }
1384 }
1385 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1386 return 0;
1387 }
1388
1389 if (tcp_checksum_complete(skb))
1390 goto csum_err;
1391
1392 if (sk->sk_state == TCP_LISTEN) {
1393 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1394
1395 if (!nsk)
1396 goto discard;
1397 if (nsk != sk) {
1398 sock_rps_save_rxhash(nsk, skb);
1399 sk_mark_napi_id(nsk, skb);
1400 if (tcp_child_process(sk, nsk, skb)) {
1401 rsk = nsk;
1402 goto reset;
1403 }
1404 return 0;
1405 }
1406 } else
1407 sock_rps_save_rxhash(sk, skb);
1408
1409 if (tcp_rcv_state_process(sk, skb)) {
1410 rsk = sk;
1411 goto reset;
1412 }
1413 return 0;
1414
1415 reset:
1416 tcp_v4_send_reset(rsk, skb);
1417 discard:
1418 kfree_skb(skb);
1419 /* Be careful here. If this function gets more complicated and
1420 * gcc suffers from register pressure on the x86, sk (in %ebx)
1421 * might be destroyed here. This current version compiles correctly,
1422 * but you have been warned.
1423 */
1424 return 0;
1425
1426 csum_err:
1427 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1428 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1429 goto discard;
1430 }
1431 EXPORT_SYMBOL(tcp_v4_do_rcv);
1432
1433 void tcp_v4_early_demux(struct sk_buff *skb)
1434 {
1435 const struct iphdr *iph;
1436 const struct tcphdr *th;
1437 struct sock *sk;
1438
1439 if (skb->pkt_type != PACKET_HOST)
1440 return;
1441
1442 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1443 return;
1444
1445 iph = ip_hdr(skb);
1446 th = tcp_hdr(skb);
1447
1448 if (th->doff < sizeof(struct tcphdr) / 4)
1449 return;
1450
1451 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1452 iph->saddr, th->source,
1453 iph->daddr, ntohs(th->dest),
1454 skb->skb_iif);
1455 if (sk) {
1456 skb->sk = sk;
1457 skb->destructor = sock_edemux;
1458 if (sk_fullsock(sk)) {
1459 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1460
1461 if (dst)
1462 dst = dst_check(dst, 0);
1463 if (dst &&
1464 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1465 skb_dst_set_noref(skb, dst);
1466 }
1467 }
1468 }
1469
1470 /* Packet is added to VJ-style prequeue for processing in process
1471 * context, if a reader task is waiting. Apparently, this exciting
1472 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1473 * failed somewhere. Latency? Burstiness? Well, at least now we will
1474 * see, why it failed. 8)8) --ANK
1475 *
1476 */
1477 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1478 {
1479 struct tcp_sock *tp = tcp_sk(sk);
1480
1481 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1482 return false;
1483
1484 if (skb->len <= tcp_hdrlen(skb) &&
1485 skb_queue_len(&tp->ucopy.prequeue) == 0)
1486 return false;
1487
1488 /* Before escaping RCU protected region, we need to take care of skb
1489 * dst. Prequeue is only enabled for established sockets.
1490 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1491 * Instead of doing full sk_rx_dst validity here, let's perform
1492 * an optimistic check.
1493 */
1494 if (likely(sk->sk_rx_dst))
1495 skb_dst_drop(skb);
1496 else
1497 skb_dst_force_safe(skb);
1498
1499 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1500 tp->ucopy.memory += skb->truesize;
1501 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1502 struct sk_buff *skb1;
1503
1504 BUG_ON(sock_owned_by_user(sk));
1505
1506 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1507 sk_backlog_rcv(sk, skb1);
1508 NET_INC_STATS_BH(sock_net(sk),
1509 LINUX_MIB_TCPPREQUEUEDROPPED);
1510 }
1511
1512 tp->ucopy.memory = 0;
1513 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1514 wake_up_interruptible_sync_poll(sk_sleep(sk),
1515 POLLIN | POLLRDNORM | POLLRDBAND);
1516 if (!inet_csk_ack_scheduled(sk))
1517 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1518 (3 * tcp_rto_min(sk)) / 4,
1519 TCP_RTO_MAX);
1520 }
1521 return true;
1522 }
1523 EXPORT_SYMBOL(tcp_prequeue);
1524
1525 /*
1526 * From tcp_input.c
1527 */
1528
1529 int tcp_v4_rcv(struct sk_buff *skb)
1530 {
1531 const struct iphdr *iph;
1532 const struct tcphdr *th;
1533 struct sock *sk;
1534 int ret;
1535 struct net *net = dev_net(skb->dev);
1536
1537 if (skb->pkt_type != PACKET_HOST)
1538 goto discard_it;
1539
1540 /* Count it even if it's bad */
1541 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1542
1543 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1544 goto discard_it;
1545
1546 th = tcp_hdr(skb);
1547
1548 if (th->doff < sizeof(struct tcphdr) / 4)
1549 goto bad_packet;
1550 if (!pskb_may_pull(skb, th->doff * 4))
1551 goto discard_it;
1552
1553 /* An explanation is required here, I think.
1554 * Packet length and doff are validated by header prediction,
1555 * provided case of th->doff==0 is eliminated.
1556 * So, we defer the checks. */
1557
1558 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1559 goto csum_error;
1560
1561 th = tcp_hdr(skb);
1562 iph = ip_hdr(skb);
1563 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1564 * barrier() makes sure compiler wont play fool^Waliasing games.
1565 */
1566 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1567 sizeof(struct inet_skb_parm));
1568 barrier();
1569
1570 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1571 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1572 skb->len - th->doff * 4);
1573 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1574 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1575 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1576 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1577 TCP_SKB_CB(skb)->sacked = 0;
1578
1579 lookup:
1580 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1581 if (!sk)
1582 goto no_tcp_socket;
1583
1584 process:
1585 if (sk->sk_state == TCP_TIME_WAIT)
1586 goto do_time_wait;
1587
1588 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1589 struct request_sock *req = inet_reqsk(sk);
1590 struct sock *nsk = NULL;
1591
1592 sk = req->rsk_listener;
1593 if (tcp_v4_inbound_md5_hash(sk, skb))
1594 goto discard_and_relse;
1595 if (likely(sk->sk_state == TCP_LISTEN)) {
1596 nsk = tcp_check_req(sk, skb, req, false);
1597 } else {
1598 inet_csk_reqsk_queue_drop_and_put(sk, req);
1599 goto lookup;
1600 }
1601 if (!nsk) {
1602 reqsk_put(req);
1603 goto discard_it;
1604 }
1605 if (nsk == sk) {
1606 sock_hold(sk);
1607 reqsk_put(req);
1608 } else if (tcp_child_process(sk, nsk, skb)) {
1609 tcp_v4_send_reset(nsk, skb);
1610 goto discard_it;
1611 } else {
1612 return 0;
1613 }
1614 }
1615 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1616 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1617 goto discard_and_relse;
1618 }
1619
1620 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1621 goto discard_and_relse;
1622
1623 if (tcp_v4_inbound_md5_hash(sk, skb))
1624 goto discard_and_relse;
1625
1626 nf_reset(skb);
1627
1628 if (sk_filter(sk, skb))
1629 goto discard_and_relse;
1630
1631 skb->dev = NULL;
1632
1633 if (sk->sk_state == TCP_LISTEN) {
1634 ret = tcp_v4_do_rcv(sk, skb);
1635 goto put_and_return;
1636 }
1637
1638 sk_incoming_cpu_update(sk);
1639
1640 bh_lock_sock_nested(sk);
1641 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1642 ret = 0;
1643 if (!sock_owned_by_user(sk)) {
1644 if (!tcp_prequeue(sk, skb))
1645 ret = tcp_v4_do_rcv(sk, skb);
1646 } else if (unlikely(sk_add_backlog(sk, skb,
1647 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1648 bh_unlock_sock(sk);
1649 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1650 goto discard_and_relse;
1651 }
1652 bh_unlock_sock(sk);
1653
1654 put_and_return:
1655 sock_put(sk);
1656
1657 return ret;
1658
1659 no_tcp_socket:
1660 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1661 goto discard_it;
1662
1663 if (tcp_checksum_complete(skb)) {
1664 csum_error:
1665 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1666 bad_packet:
1667 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1668 } else {
1669 tcp_v4_send_reset(NULL, skb);
1670 }
1671
1672 discard_it:
1673 /* Discard frame. */
1674 kfree_skb(skb);
1675 return 0;
1676
1677 discard_and_relse:
1678 sock_put(sk);
1679 goto discard_it;
1680
1681 do_time_wait:
1682 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1683 inet_twsk_put(inet_twsk(sk));
1684 goto discard_it;
1685 }
1686
1687 if (tcp_checksum_complete(skb)) {
1688 inet_twsk_put(inet_twsk(sk));
1689 goto csum_error;
1690 }
1691 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1692 case TCP_TW_SYN: {
1693 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1694 &tcp_hashinfo,
1695 iph->saddr, th->source,
1696 iph->daddr, th->dest,
1697 inet_iif(skb));
1698 if (sk2) {
1699 inet_twsk_deschedule_put(inet_twsk(sk));
1700 sk = sk2;
1701 goto process;
1702 }
1703 /* Fall through to ACK */
1704 }
1705 case TCP_TW_ACK:
1706 tcp_v4_timewait_ack(sk, skb);
1707 break;
1708 case TCP_TW_RST:
1709 goto no_tcp_socket;
1710 case TCP_TW_SUCCESS:;
1711 }
1712 goto discard_it;
1713 }
1714
1715 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1716 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1717 .twsk_unique = tcp_twsk_unique,
1718 .twsk_destructor= tcp_twsk_destructor,
1719 };
1720
1721 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1722 {
1723 struct dst_entry *dst = skb_dst(skb);
1724
1725 if (dst && dst_hold_safe(dst)) {
1726 sk->sk_rx_dst = dst;
1727 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1728 }
1729 }
1730 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1731
1732 const struct inet_connection_sock_af_ops ipv4_specific = {
1733 .queue_xmit = ip_queue_xmit,
1734 .send_check = tcp_v4_send_check,
1735 .rebuild_header = inet_sk_rebuild_header,
1736 .sk_rx_dst_set = inet_sk_rx_dst_set,
1737 .conn_request = tcp_v4_conn_request,
1738 .syn_recv_sock = tcp_v4_syn_recv_sock,
1739 .net_header_len = sizeof(struct iphdr),
1740 .setsockopt = ip_setsockopt,
1741 .getsockopt = ip_getsockopt,
1742 .addr2sockaddr = inet_csk_addr2sockaddr,
1743 .sockaddr_len = sizeof(struct sockaddr_in),
1744 .bind_conflict = inet_csk_bind_conflict,
1745 #ifdef CONFIG_COMPAT
1746 .compat_setsockopt = compat_ip_setsockopt,
1747 .compat_getsockopt = compat_ip_getsockopt,
1748 #endif
1749 .mtu_reduced = tcp_v4_mtu_reduced,
1750 };
1751 EXPORT_SYMBOL(ipv4_specific);
1752
1753 #ifdef CONFIG_TCP_MD5SIG
1754 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1755 .md5_lookup = tcp_v4_md5_lookup,
1756 .calc_md5_hash = tcp_v4_md5_hash_skb,
1757 .md5_parse = tcp_v4_parse_md5_keys,
1758 };
1759 #endif
1760
1761 /* NOTE: A lot of things set to zero explicitly by call to
1762 * sk_alloc() so need not be done here.
1763 */
1764 static int tcp_v4_init_sock(struct sock *sk)
1765 {
1766 struct inet_connection_sock *icsk = inet_csk(sk);
1767
1768 tcp_init_sock(sk);
1769
1770 icsk->icsk_af_ops = &ipv4_specific;
1771
1772 #ifdef CONFIG_TCP_MD5SIG
1773 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1774 #endif
1775
1776 return 0;
1777 }
1778
1779 void tcp_v4_destroy_sock(struct sock *sk)
1780 {
1781 struct tcp_sock *tp = tcp_sk(sk);
1782
1783 tcp_clear_xmit_timers(sk);
1784
1785 tcp_cleanup_congestion_control(sk);
1786
1787 /* Cleanup up the write buffer. */
1788 tcp_write_queue_purge(sk);
1789
1790 /* Cleans up our, hopefully empty, out_of_order_queue. */
1791 __skb_queue_purge(&tp->out_of_order_queue);
1792
1793 #ifdef CONFIG_TCP_MD5SIG
1794 /* Clean up the MD5 key list, if any */
1795 if (tp->md5sig_info) {
1796 tcp_clear_md5_list(sk);
1797 kfree_rcu(tp->md5sig_info, rcu);
1798 tp->md5sig_info = NULL;
1799 }
1800 #endif
1801
1802 /* Clean prequeue, it must be empty really */
1803 __skb_queue_purge(&tp->ucopy.prequeue);
1804
1805 /* Clean up a referenced TCP bind bucket. */
1806 if (inet_csk(sk)->icsk_bind_hash)
1807 inet_put_port(sk);
1808
1809 BUG_ON(tp->fastopen_rsk);
1810
1811 /* If socket is aborted during connect operation */
1812 tcp_free_fastopen_req(tp);
1813 tcp_saved_syn_free(tp);
1814
1815 sk_sockets_allocated_dec(sk);
1816 sock_release_memcg(sk);
1817 }
1818 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1819
1820 #ifdef CONFIG_PROC_FS
1821 /* Proc filesystem TCP sock list dumping. */
1822
1823 /*
1824 * Get next listener socket follow cur. If cur is NULL, get first socket
1825 * starting from bucket given in st->bucket; when st->bucket is zero the
1826 * very first socket in the hash table is returned.
1827 */
1828 static void *listening_get_next(struct seq_file *seq, void *cur)
1829 {
1830 struct inet_connection_sock *icsk;
1831 struct hlist_nulls_node *node;
1832 struct sock *sk = cur;
1833 struct inet_listen_hashbucket *ilb;
1834 struct tcp_iter_state *st = seq->private;
1835 struct net *net = seq_file_net(seq);
1836
1837 if (!sk) {
1838 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1839 spin_lock_bh(&ilb->lock);
1840 sk = sk_nulls_head(&ilb->head);
1841 st->offset = 0;
1842 goto get_sk;
1843 }
1844 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1845 ++st->num;
1846 ++st->offset;
1847
1848 sk = sk_nulls_next(sk);
1849 get_sk:
1850 sk_nulls_for_each_from(sk, node) {
1851 if (!net_eq(sock_net(sk), net))
1852 continue;
1853 if (sk->sk_family == st->family) {
1854 cur = sk;
1855 goto out;
1856 }
1857 icsk = inet_csk(sk);
1858 }
1859 spin_unlock_bh(&ilb->lock);
1860 st->offset = 0;
1861 if (++st->bucket < INET_LHTABLE_SIZE) {
1862 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1863 spin_lock_bh(&ilb->lock);
1864 sk = sk_nulls_head(&ilb->head);
1865 goto get_sk;
1866 }
1867 cur = NULL;
1868 out:
1869 return cur;
1870 }
1871
1872 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1873 {
1874 struct tcp_iter_state *st = seq->private;
1875 void *rc;
1876
1877 st->bucket = 0;
1878 st->offset = 0;
1879 rc = listening_get_next(seq, NULL);
1880
1881 while (rc && *pos) {
1882 rc = listening_get_next(seq, rc);
1883 --*pos;
1884 }
1885 return rc;
1886 }
1887
1888 static inline bool empty_bucket(const struct tcp_iter_state *st)
1889 {
1890 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1891 }
1892
1893 /*
1894 * Get first established socket starting from bucket given in st->bucket.
1895 * If st->bucket is zero, the very first socket in the hash is returned.
1896 */
1897 static void *established_get_first(struct seq_file *seq)
1898 {
1899 struct tcp_iter_state *st = seq->private;
1900 struct net *net = seq_file_net(seq);
1901 void *rc = NULL;
1902
1903 st->offset = 0;
1904 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1905 struct sock *sk;
1906 struct hlist_nulls_node *node;
1907 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1908
1909 /* Lockless fast path for the common case of empty buckets */
1910 if (empty_bucket(st))
1911 continue;
1912
1913 spin_lock_bh(lock);
1914 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1915 if (sk->sk_family != st->family ||
1916 !net_eq(sock_net(sk), net)) {
1917 continue;
1918 }
1919 rc = sk;
1920 goto out;
1921 }
1922 spin_unlock_bh(lock);
1923 }
1924 out:
1925 return rc;
1926 }
1927
1928 static void *established_get_next(struct seq_file *seq, void *cur)
1929 {
1930 struct sock *sk = cur;
1931 struct hlist_nulls_node *node;
1932 struct tcp_iter_state *st = seq->private;
1933 struct net *net = seq_file_net(seq);
1934
1935 ++st->num;
1936 ++st->offset;
1937
1938 sk = sk_nulls_next(sk);
1939
1940 sk_nulls_for_each_from(sk, node) {
1941 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1942 return sk;
1943 }
1944
1945 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1946 ++st->bucket;
1947 return established_get_first(seq);
1948 }
1949
1950 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1951 {
1952 struct tcp_iter_state *st = seq->private;
1953 void *rc;
1954
1955 st->bucket = 0;
1956 rc = established_get_first(seq);
1957
1958 while (rc && pos) {
1959 rc = established_get_next(seq, rc);
1960 --pos;
1961 }
1962 return rc;
1963 }
1964
1965 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1966 {
1967 void *rc;
1968 struct tcp_iter_state *st = seq->private;
1969
1970 st->state = TCP_SEQ_STATE_LISTENING;
1971 rc = listening_get_idx(seq, &pos);
1972
1973 if (!rc) {
1974 st->state = TCP_SEQ_STATE_ESTABLISHED;
1975 rc = established_get_idx(seq, pos);
1976 }
1977
1978 return rc;
1979 }
1980
1981 static void *tcp_seek_last_pos(struct seq_file *seq)
1982 {
1983 struct tcp_iter_state *st = seq->private;
1984 int offset = st->offset;
1985 int orig_num = st->num;
1986 void *rc = NULL;
1987
1988 switch (st->state) {
1989 case TCP_SEQ_STATE_LISTENING:
1990 if (st->bucket >= INET_LHTABLE_SIZE)
1991 break;
1992 st->state = TCP_SEQ_STATE_LISTENING;
1993 rc = listening_get_next(seq, NULL);
1994 while (offset-- && rc)
1995 rc = listening_get_next(seq, rc);
1996 if (rc)
1997 break;
1998 st->bucket = 0;
1999 st->state = TCP_SEQ_STATE_ESTABLISHED;
2000 /* Fallthrough */
2001 case TCP_SEQ_STATE_ESTABLISHED:
2002 if (st->bucket > tcp_hashinfo.ehash_mask)
2003 break;
2004 rc = established_get_first(seq);
2005 while (offset-- && rc)
2006 rc = established_get_next(seq, rc);
2007 }
2008
2009 st->num = orig_num;
2010
2011 return rc;
2012 }
2013
2014 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2015 {
2016 struct tcp_iter_state *st = seq->private;
2017 void *rc;
2018
2019 if (*pos && *pos == st->last_pos) {
2020 rc = tcp_seek_last_pos(seq);
2021 if (rc)
2022 goto out;
2023 }
2024
2025 st->state = TCP_SEQ_STATE_LISTENING;
2026 st->num = 0;
2027 st->bucket = 0;
2028 st->offset = 0;
2029 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2030
2031 out:
2032 st->last_pos = *pos;
2033 return rc;
2034 }
2035
2036 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2037 {
2038 struct tcp_iter_state *st = seq->private;
2039 void *rc = NULL;
2040
2041 if (v == SEQ_START_TOKEN) {
2042 rc = tcp_get_idx(seq, 0);
2043 goto out;
2044 }
2045
2046 switch (st->state) {
2047 case TCP_SEQ_STATE_LISTENING:
2048 rc = listening_get_next(seq, v);
2049 if (!rc) {
2050 st->state = TCP_SEQ_STATE_ESTABLISHED;
2051 st->bucket = 0;
2052 st->offset = 0;
2053 rc = established_get_first(seq);
2054 }
2055 break;
2056 case TCP_SEQ_STATE_ESTABLISHED:
2057 rc = established_get_next(seq, v);
2058 break;
2059 }
2060 out:
2061 ++*pos;
2062 st->last_pos = *pos;
2063 return rc;
2064 }
2065
2066 static void tcp_seq_stop(struct seq_file *seq, void *v)
2067 {
2068 struct tcp_iter_state *st = seq->private;
2069
2070 switch (st->state) {
2071 case TCP_SEQ_STATE_LISTENING:
2072 if (v != SEQ_START_TOKEN)
2073 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2074 break;
2075 case TCP_SEQ_STATE_ESTABLISHED:
2076 if (v)
2077 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2078 break;
2079 }
2080 }
2081
2082 int tcp_seq_open(struct inode *inode, struct file *file)
2083 {
2084 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2085 struct tcp_iter_state *s;
2086 int err;
2087
2088 err = seq_open_net(inode, file, &afinfo->seq_ops,
2089 sizeof(struct tcp_iter_state));
2090 if (err < 0)
2091 return err;
2092
2093 s = ((struct seq_file *)file->private_data)->private;
2094 s->family = afinfo->family;
2095 s->last_pos = 0;
2096 return 0;
2097 }
2098 EXPORT_SYMBOL(tcp_seq_open);
2099
2100 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2101 {
2102 int rc = 0;
2103 struct proc_dir_entry *p;
2104
2105 afinfo->seq_ops.start = tcp_seq_start;
2106 afinfo->seq_ops.next = tcp_seq_next;
2107 afinfo->seq_ops.stop = tcp_seq_stop;
2108
2109 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2110 afinfo->seq_fops, afinfo);
2111 if (!p)
2112 rc = -ENOMEM;
2113 return rc;
2114 }
2115 EXPORT_SYMBOL(tcp_proc_register);
2116
2117 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2118 {
2119 remove_proc_entry(afinfo->name, net->proc_net);
2120 }
2121 EXPORT_SYMBOL(tcp_proc_unregister);
2122
2123 static void get_openreq4(const struct request_sock *req,
2124 struct seq_file *f, int i)
2125 {
2126 const struct inet_request_sock *ireq = inet_rsk(req);
2127 long delta = req->rsk_timer.expires - jiffies;
2128
2129 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2130 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2131 i,
2132 ireq->ir_loc_addr,
2133 ireq->ir_num,
2134 ireq->ir_rmt_addr,
2135 ntohs(ireq->ir_rmt_port),
2136 TCP_SYN_RECV,
2137 0, 0, /* could print option size, but that is af dependent. */
2138 1, /* timers active (only the expire timer) */
2139 jiffies_delta_to_clock_t(delta),
2140 req->num_timeout,
2141 from_kuid_munged(seq_user_ns(f),
2142 sock_i_uid(req->rsk_listener)),
2143 0, /* non standard timer */
2144 0, /* open_requests have no inode */
2145 0,
2146 req);
2147 }
2148
2149 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2150 {
2151 int timer_active;
2152 unsigned long timer_expires;
2153 const struct tcp_sock *tp = tcp_sk(sk);
2154 const struct inet_connection_sock *icsk = inet_csk(sk);
2155 const struct inet_sock *inet = inet_sk(sk);
2156 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2157 __be32 dest = inet->inet_daddr;
2158 __be32 src = inet->inet_rcv_saddr;
2159 __u16 destp = ntohs(inet->inet_dport);
2160 __u16 srcp = ntohs(inet->inet_sport);
2161 int rx_queue;
2162 int state;
2163
2164 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2165 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2166 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2167 timer_active = 1;
2168 timer_expires = icsk->icsk_timeout;
2169 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2170 timer_active = 4;
2171 timer_expires = icsk->icsk_timeout;
2172 } else if (timer_pending(&sk->sk_timer)) {
2173 timer_active = 2;
2174 timer_expires = sk->sk_timer.expires;
2175 } else {
2176 timer_active = 0;
2177 timer_expires = jiffies;
2178 }
2179
2180 state = sk_state_load(sk);
2181 if (state == TCP_LISTEN)
2182 rx_queue = sk->sk_ack_backlog;
2183 else
2184 /* Because we don't lock the socket,
2185 * we might find a transient negative value.
2186 */
2187 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2188
2189 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2190 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2191 i, src, srcp, dest, destp, state,
2192 tp->write_seq - tp->snd_una,
2193 rx_queue,
2194 timer_active,
2195 jiffies_delta_to_clock_t(timer_expires - jiffies),
2196 icsk->icsk_retransmits,
2197 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2198 icsk->icsk_probes_out,
2199 sock_i_ino(sk),
2200 atomic_read(&sk->sk_refcnt), sk,
2201 jiffies_to_clock_t(icsk->icsk_rto),
2202 jiffies_to_clock_t(icsk->icsk_ack.ato),
2203 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2204 tp->snd_cwnd,
2205 state == TCP_LISTEN ?
2206 fastopenq->max_qlen :
2207 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2208 }
2209
2210 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2211 struct seq_file *f, int i)
2212 {
2213 long delta = tw->tw_timer.expires - jiffies;
2214 __be32 dest, src;
2215 __u16 destp, srcp;
2216
2217 dest = tw->tw_daddr;
2218 src = tw->tw_rcv_saddr;
2219 destp = ntohs(tw->tw_dport);
2220 srcp = ntohs(tw->tw_sport);
2221
2222 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2223 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2224 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2225 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2226 atomic_read(&tw->tw_refcnt), tw);
2227 }
2228
2229 #define TMPSZ 150
2230
2231 static int tcp4_seq_show(struct seq_file *seq, void *v)
2232 {
2233 struct tcp_iter_state *st;
2234 struct sock *sk = v;
2235
2236 seq_setwidth(seq, TMPSZ - 1);
2237 if (v == SEQ_START_TOKEN) {
2238 seq_puts(seq, " sl local_address rem_address st tx_queue "
2239 "rx_queue tr tm->when retrnsmt uid timeout "
2240 "inode");
2241 goto out;
2242 }
2243 st = seq->private;
2244
2245 if (sk->sk_state == TCP_TIME_WAIT)
2246 get_timewait4_sock(v, seq, st->num);
2247 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2248 get_openreq4(v, seq, st->num);
2249 else
2250 get_tcp4_sock(v, seq, st->num);
2251 out:
2252 seq_pad(seq, '\n');
2253 return 0;
2254 }
2255
2256 static const struct file_operations tcp_afinfo_seq_fops = {
2257 .owner = THIS_MODULE,
2258 .open = tcp_seq_open,
2259 .read = seq_read,
2260 .llseek = seq_lseek,
2261 .release = seq_release_net
2262 };
2263
2264 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2265 .name = "tcp",
2266 .family = AF_INET,
2267 .seq_fops = &tcp_afinfo_seq_fops,
2268 .seq_ops = {
2269 .show = tcp4_seq_show,
2270 },
2271 };
2272
2273 static int __net_init tcp4_proc_init_net(struct net *net)
2274 {
2275 return tcp_proc_register(net, &tcp4_seq_afinfo);
2276 }
2277
2278 static void __net_exit tcp4_proc_exit_net(struct net *net)
2279 {
2280 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2281 }
2282
2283 static struct pernet_operations tcp4_net_ops = {
2284 .init = tcp4_proc_init_net,
2285 .exit = tcp4_proc_exit_net,
2286 };
2287
2288 int __init tcp4_proc_init(void)
2289 {
2290 return register_pernet_subsys(&tcp4_net_ops);
2291 }
2292
2293 void tcp4_proc_exit(void)
2294 {
2295 unregister_pernet_subsys(&tcp4_net_ops);
2296 }
2297 #endif /* CONFIG_PROC_FS */
2298
2299 struct proto tcp_prot = {
2300 .name = "TCP",
2301 .owner = THIS_MODULE,
2302 .close = tcp_close,
2303 .connect = tcp_v4_connect,
2304 .disconnect = tcp_disconnect,
2305 .accept = inet_csk_accept,
2306 .ioctl = tcp_ioctl,
2307 .init = tcp_v4_init_sock,
2308 .destroy = tcp_v4_destroy_sock,
2309 .shutdown = tcp_shutdown,
2310 .setsockopt = tcp_setsockopt,
2311 .getsockopt = tcp_getsockopt,
2312 .recvmsg = tcp_recvmsg,
2313 .sendmsg = tcp_sendmsg,
2314 .sendpage = tcp_sendpage,
2315 .backlog_rcv = tcp_v4_do_rcv,
2316 .release_cb = tcp_release_cb,
2317 .hash = inet_hash,
2318 .unhash = inet_unhash,
2319 .get_port = inet_csk_get_port,
2320 .enter_memory_pressure = tcp_enter_memory_pressure,
2321 .stream_memory_free = tcp_stream_memory_free,
2322 .sockets_allocated = &tcp_sockets_allocated,
2323 .orphan_count = &tcp_orphan_count,
2324 .memory_allocated = &tcp_memory_allocated,
2325 .memory_pressure = &tcp_memory_pressure,
2326 .sysctl_mem = sysctl_tcp_mem,
2327 .sysctl_wmem = sysctl_tcp_wmem,
2328 .sysctl_rmem = sysctl_tcp_rmem,
2329 .max_header = MAX_TCP_HEADER,
2330 .obj_size = sizeof(struct tcp_sock),
2331 .slab_flags = SLAB_DESTROY_BY_RCU,
2332 .twsk_prot = &tcp_timewait_sock_ops,
2333 .rsk_prot = &tcp_request_sock_ops,
2334 .h.hashinfo = &tcp_hashinfo,
2335 .no_autobind = true,
2336 #ifdef CONFIG_COMPAT
2337 .compat_setsockopt = compat_tcp_setsockopt,
2338 .compat_getsockopt = compat_tcp_getsockopt,
2339 #endif
2340 #ifdef CONFIG_MEMCG_KMEM
2341 .init_cgroup = tcp_init_cgroup,
2342 .destroy_cgroup = tcp_destroy_cgroup,
2343 .proto_cgroup = tcp_proto_cgroup,
2344 #endif
2345 .diag_destroy = tcp_abort,
2346 };
2347 EXPORT_SYMBOL(tcp_prot);
2348
2349 static void __net_exit tcp_sk_exit(struct net *net)
2350 {
2351 int cpu;
2352
2353 for_each_possible_cpu(cpu)
2354 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2355 free_percpu(net->ipv4.tcp_sk);
2356 }
2357
2358 static int __net_init tcp_sk_init(struct net *net)
2359 {
2360 int res, cpu;
2361
2362 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2363 if (!net->ipv4.tcp_sk)
2364 return -ENOMEM;
2365
2366 for_each_possible_cpu(cpu) {
2367 struct sock *sk;
2368
2369 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2370 IPPROTO_TCP, net);
2371 if (res)
2372 goto fail;
2373 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2374 }
2375
2376 net->ipv4.sysctl_tcp_ecn = 2;
2377 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2378
2379 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2380 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2381 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2382
2383 return 0;
2384 fail:
2385 tcp_sk_exit(net);
2386
2387 return res;
2388 }
2389
2390 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2391 {
2392 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2393 }
2394
2395 static struct pernet_operations __net_initdata tcp_sk_ops = {
2396 .init = tcp_sk_init,
2397 .exit = tcp_sk_exit,
2398 .exit_batch = tcp_sk_exit_batch,
2399 };
2400
2401 void __init tcp_v4_init(void)
2402 {
2403 inet_hashinfo_init(&tcp_hashinfo);
2404 if (register_pernet_subsys(&tcp_sk_ops))
2405 panic("Failed to create the TCP control socket.\n");
2406 }
Linux kernel - Deliverables
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