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irqchip: Fix dependencies for archs w/o HAS_IOMEM
[linux/fpc-iii.git] / net / ipv4 / tcp_ipv4.c
blobd8841a2f15691fd80c46fbaa62e2431e9ca16003
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 newinet->inet_saddr = ireq->ir_loc_addr;
1280 inet_opt = ireq->opt;
1281 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1282 ireq->opt = NULL;
1283 newinet->mc_index = inet_iif(skb);
1284 newinet->mc_ttl = ip_hdr(skb)->ttl;
1285 newinet->rcv_tos = ip_hdr(skb)->tos;
1286 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1287 if (inet_opt)
1288 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1289 newinet->inet_id = newtp->write_seq ^ jiffies;
1290
1291 if (!dst) {
1292 dst = inet_csk_route_child_sock(sk, newsk, req);
1293 if (!dst)
1294 goto put_and_exit;
1295 } else {
1296 /* syncookie case : see end of cookie_v4_check() */
1297 }
1298 sk_setup_caps(newsk, dst);
1299
1300 tcp_ca_openreq_child(newsk, dst);
1301
1302 tcp_sync_mss(newsk, dst_mtu(dst));
1303 newtp->advmss = dst_metric_advmss(dst);
1304 if (tcp_sk(sk)->rx_opt.user_mss &&
1305 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1306 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1307
1308 tcp_initialize_rcv_mss(newsk);
1309
1310 #ifdef CONFIG_TCP_MD5SIG
1311 /* Copy over the MD5 key from the original socket */
1312 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1313 AF_INET);
1314 if (key) {
1315 /*
1316 * We're using one, so create a matching key
1317 * on the newsk structure. If we fail to get
1318 * memory, then we end up not copying the key
1319 * across. Shucks.
1320 */
1321 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1322 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1323 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1324 }
1325 #endif
1326
1327 if (__inet_inherit_port(sk, newsk) < 0)
1328 goto put_and_exit;
1329 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1330 if (*own_req)
1331 tcp_move_syn(newtp, req);
1332
1333 return newsk;
1334
1335 exit_overflow:
1336 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1337 exit_nonewsk:
1338 dst_release(dst);
1339 exit:
1340 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1341 return NULL;
1342 put_and_exit:
1343 inet_csk_prepare_forced_close(newsk);
1344 tcp_done(newsk);
1345 goto exit;
1346 }
1347 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1348
1349 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1350 {
1351 #ifdef CONFIG_SYN_COOKIES
1352 const struct tcphdr *th = tcp_hdr(skb);
1353
1354 if (!th->syn)
1355 sk = cookie_v4_check(sk, skb);
1356 #endif
1357 return sk;
1358 }
1359
1360 /* The socket must have it's spinlock held when we get
1361 * here, unless it is a TCP_LISTEN socket.
1362 *
1363 * We have a potential double-lock case here, so even when
1364 * doing backlog processing we use the BH locking scheme.
1365 * This is because we cannot sleep with the original spinlock
1366 * held.
1367 */
1368 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1369 {
1370 struct sock *rsk;
1371
1372 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1373 struct dst_entry *dst = sk->sk_rx_dst;
1374
1375 sock_rps_save_rxhash(sk, skb);
1376 sk_mark_napi_id(sk, skb);
1377 if (dst) {
1378 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1379 !dst->ops->check(dst, 0)) {
1380 dst_release(dst);
1381 sk->sk_rx_dst = NULL;
1382 }
1383 }
1384 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1385 return 0;
1386 }
1387
1388 if (tcp_checksum_complete(skb))
1389 goto csum_err;
1390
1391 if (sk->sk_state == TCP_LISTEN) {
1392 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1393
1394 if (!nsk)
1395 goto discard;
1396 if (nsk != sk) {
1397 sock_rps_save_rxhash(nsk, skb);
1398 sk_mark_napi_id(nsk, skb);
1399 if (tcp_child_process(sk, nsk, skb)) {
1400 rsk = nsk;
1401 goto reset;
1402 }
1403 return 0;
1404 }
1405 } else
1406 sock_rps_save_rxhash(sk, skb);
1407
1408 if (tcp_rcv_state_process(sk, skb)) {
1409 rsk = sk;
1410 goto reset;
1411 }
1412 return 0;
1413
1414 reset:
1415 tcp_v4_send_reset(rsk, skb);
1416 discard:
1417 kfree_skb(skb);
1418 /* Be careful here. If this function gets more complicated and
1419 * gcc suffers from register pressure on the x86, sk (in %ebx)
1420 * might be destroyed here. This current version compiles correctly,
1421 * but you have been warned.
1422 */
1423 return 0;
1424
1425 csum_err:
1426 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1427 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1428 goto discard;
1429 }
1430 EXPORT_SYMBOL(tcp_v4_do_rcv);
1431
1432 void tcp_v4_early_demux(struct sk_buff *skb)
1433 {
1434 const struct iphdr *iph;
1435 const struct tcphdr *th;
1436 struct sock *sk;
1437
1438 if (skb->pkt_type != PACKET_HOST)
1439 return;
1440
1441 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1442 return;
1443
1444 iph = ip_hdr(skb);
1445 th = tcp_hdr(skb);
1446
1447 if (th->doff < sizeof(struct tcphdr) / 4)
1448 return;
1449
1450 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1451 iph->saddr, th->source,
1452 iph->daddr, ntohs(th->dest),
1453 skb->skb_iif);
1454 if (sk) {
1455 skb->sk = sk;
1456 skb->destructor = sock_edemux;
1457 if (sk_fullsock(sk)) {
1458 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1459
1460 if (dst)
1461 dst = dst_check(dst, 0);
1462 if (dst &&
1463 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1464 skb_dst_set_noref(skb, dst);
1465 }
1466 }
1467 }
1468
1469 /* Packet is added to VJ-style prequeue for processing in process
1470 * context, if a reader task is waiting. Apparently, this exciting
1471 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1472 * failed somewhere. Latency? Burstiness? Well, at least now we will
1473 * see, why it failed. 8)8) --ANK
1474 *
1475 */
1476 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1477 {
1478 struct tcp_sock *tp = tcp_sk(sk);
1479
1480 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1481 return false;
1482
1483 if (skb->len <= tcp_hdrlen(skb) &&
1484 skb_queue_len(&tp->ucopy.prequeue) == 0)
1485 return false;
1486
1487 /* Before escaping RCU protected region, we need to take care of skb
1488 * dst. Prequeue is only enabled for established sockets.
1489 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1490 * Instead of doing full sk_rx_dst validity here, let's perform
1491 * an optimistic check.
1492 */
1493 if (likely(sk->sk_rx_dst))
1494 skb_dst_drop(skb);
1495 else
1496 skb_dst_force_safe(skb);
1497
1498 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1499 tp->ucopy.memory += skb->truesize;
1500 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1501 struct sk_buff *skb1;
1502
1503 BUG_ON(sock_owned_by_user(sk));
1504
1505 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1506 sk_backlog_rcv(sk, skb1);
1507 NET_INC_STATS_BH(sock_net(sk),
1508 LINUX_MIB_TCPPREQUEUEDROPPED);
1509 }
1510
1511 tp->ucopy.memory = 0;
1512 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1513 wake_up_interruptible_sync_poll(sk_sleep(sk),
1514 POLLIN | POLLRDNORM | POLLRDBAND);
1515 if (!inet_csk_ack_scheduled(sk))
1516 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1517 (3 * tcp_rto_min(sk)) / 4,
1518 TCP_RTO_MAX);
1519 }
1520 return true;
1521 }
1522 EXPORT_SYMBOL(tcp_prequeue);
1523
1524 /*
1525 * From tcp_input.c
1526 */
1527
1528 int tcp_v4_rcv(struct sk_buff *skb)
1529 {
1530 const struct iphdr *iph;
1531 const struct tcphdr *th;
1532 struct sock *sk;
1533 int ret;
1534 struct net *net = dev_net(skb->dev);
1535
1536 if (skb->pkt_type != PACKET_HOST)
1537 goto discard_it;
1538
1539 /* Count it even if it's bad */
1540 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1541
1542 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1543 goto discard_it;
1544
1545 th = tcp_hdr(skb);
1546
1547 if (th->doff < sizeof(struct tcphdr) / 4)
1548 goto bad_packet;
1549 if (!pskb_may_pull(skb, th->doff * 4))
1550 goto discard_it;
1551
1552 /* An explanation is required here, I think.
1553 * Packet length and doff are validated by header prediction,
1554 * provided case of th->doff==0 is eliminated.
1555 * So, we defer the checks. */
1556
1557 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1558 goto csum_error;
1559
1560 th = tcp_hdr(skb);
1561 iph = ip_hdr(skb);
1562 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1563 * barrier() makes sure compiler wont play fool^Waliasing games.
1564 */
1565 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1566 sizeof(struct inet_skb_parm));
1567 barrier();
1568
1569 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1570 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1571 skb->len - th->doff * 4);
1572 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1573 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1574 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1575 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1576 TCP_SKB_CB(skb)->sacked = 0;
1577
1578 lookup:
1579 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1580 if (!sk)
1581 goto no_tcp_socket;
1582
1583 process:
1584 if (sk->sk_state == TCP_TIME_WAIT)
1585 goto do_time_wait;
1586
1587 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1588 struct request_sock *req = inet_reqsk(sk);
1589 struct sock *nsk = NULL;
1590
1591 sk = req->rsk_listener;
1592 if (tcp_v4_inbound_md5_hash(sk, skb))
1593 goto discard_and_relse;
1594 if (likely(sk->sk_state == TCP_LISTEN)) {
1595 nsk = tcp_check_req(sk, skb, req, false);
1596 } else {
1597 inet_csk_reqsk_queue_drop_and_put(sk, req);
1598 goto lookup;
1599 }
1600 if (!nsk) {
1601 reqsk_put(req);
1602 goto discard_it;
1603 }
1604 if (nsk == sk) {
1605 sock_hold(sk);
1606 reqsk_put(req);
1607 } else if (tcp_child_process(sk, nsk, skb)) {
1608 tcp_v4_send_reset(nsk, skb);
1609 goto discard_it;
1610 } else {
1611 return 0;
1612 }
1613 }
1614 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1615 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1616 goto discard_and_relse;
1617 }
1618
1619 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1620 goto discard_and_relse;
1621
1622 if (tcp_v4_inbound_md5_hash(sk, skb))
1623 goto discard_and_relse;
1624
1625 nf_reset(skb);
1626
1627 if (sk_filter(sk, skb))
1628 goto discard_and_relse;
1629
1630 skb->dev = NULL;
1631
1632 if (sk->sk_state == TCP_LISTEN) {
1633 ret = tcp_v4_do_rcv(sk, skb);
1634 goto put_and_return;
1635 }
1636
1637 sk_incoming_cpu_update(sk);
1638
1639 bh_lock_sock_nested(sk);
1640 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1641 ret = 0;
1642 if (!sock_owned_by_user(sk)) {
1643 if (!tcp_prequeue(sk, skb))
1644 ret = tcp_v4_do_rcv(sk, skb);
1645 } else if (unlikely(sk_add_backlog(sk, skb,
1646 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1647 bh_unlock_sock(sk);
1648 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1649 goto discard_and_relse;
1650 }
1651 bh_unlock_sock(sk);
1652
1653 put_and_return:
1654 sock_put(sk);
1655
1656 return ret;
1657
1658 no_tcp_socket:
1659 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1660 goto discard_it;
1661
1662 if (tcp_checksum_complete(skb)) {
1663 csum_error:
1664 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1665 bad_packet:
1666 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1667 } else {
1668 tcp_v4_send_reset(NULL, skb);
1669 }
1670
1671 discard_it:
1672 /* Discard frame. */
1673 kfree_skb(skb);
1674 return 0;
1675
1676 discard_and_relse:
1677 sock_put(sk);
1678 goto discard_it;
1679
1680 do_time_wait:
1681 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1682 inet_twsk_put(inet_twsk(sk));
1683 goto discard_it;
1684 }
1685
1686 if (tcp_checksum_complete(skb)) {
1687 inet_twsk_put(inet_twsk(sk));
1688 goto csum_error;
1689 }
1690 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1691 case TCP_TW_SYN: {
1692 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1693 &tcp_hashinfo,
1694 iph->saddr, th->source,
1695 iph->daddr, th->dest,
1696 inet_iif(skb));
1697 if (sk2) {
1698 inet_twsk_deschedule_put(inet_twsk(sk));
1699 sk = sk2;
1700 goto process;
1701 }
1702 /* Fall through to ACK */
1703 }
1704 case TCP_TW_ACK:
1705 tcp_v4_timewait_ack(sk, skb);
1706 break;
1707 case TCP_TW_RST:
1708 goto no_tcp_socket;
1709 case TCP_TW_SUCCESS:;
1710 }
1711 goto discard_it;
1712 }
1713
1714 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1715 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1716 .twsk_unique = tcp_twsk_unique,
1717 .twsk_destructor= tcp_twsk_destructor,
1718 };
1719
1720 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1721 {
1722 struct dst_entry *dst = skb_dst(skb);
1723
1724 if (dst && dst_hold_safe(dst)) {
1725 sk->sk_rx_dst = dst;
1726 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1727 }
1728 }
1729 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1730
1731 const struct inet_connection_sock_af_ops ipv4_specific = {
1732 .queue_xmit = ip_queue_xmit,
1733 .send_check = tcp_v4_send_check,
1734 .rebuild_header = inet_sk_rebuild_header,
1735 .sk_rx_dst_set = inet_sk_rx_dst_set,
1736 .conn_request = tcp_v4_conn_request,
1737 .syn_recv_sock = tcp_v4_syn_recv_sock,
1738 .net_header_len = sizeof(struct iphdr),
1739 .setsockopt = ip_setsockopt,
1740 .getsockopt = ip_getsockopt,
1741 .addr2sockaddr = inet_csk_addr2sockaddr,
1742 .sockaddr_len = sizeof(struct sockaddr_in),
1743 .bind_conflict = inet_csk_bind_conflict,
1744 #ifdef CONFIG_COMPAT
1745 .compat_setsockopt = compat_ip_setsockopt,
1746 .compat_getsockopt = compat_ip_getsockopt,
1747 #endif
1748 .mtu_reduced = tcp_v4_mtu_reduced,
1749 };
1750 EXPORT_SYMBOL(ipv4_specific);
1751
1752 #ifdef CONFIG_TCP_MD5SIG
1753 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1754 .md5_lookup = tcp_v4_md5_lookup,
1755 .calc_md5_hash = tcp_v4_md5_hash_skb,
1756 .md5_parse = tcp_v4_parse_md5_keys,
1757 };
1758 #endif
1759
1760 /* NOTE: A lot of things set to zero explicitly by call to
1761 * sk_alloc() so need not be done here.
1762 */
1763 static int tcp_v4_init_sock(struct sock *sk)
1764 {
1765 struct inet_connection_sock *icsk = inet_csk(sk);
1766
1767 tcp_init_sock(sk);
1768
1769 icsk->icsk_af_ops = &ipv4_specific;
1770
1771 #ifdef CONFIG_TCP_MD5SIG
1772 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1773 #endif
1774
1775 return 0;
1776 }
1777
1778 void tcp_v4_destroy_sock(struct sock *sk)
1779 {
1780 struct tcp_sock *tp = tcp_sk(sk);
1781
1782 tcp_clear_xmit_timers(sk);
1783
1784 tcp_cleanup_congestion_control(sk);
1785
1786 /* Cleanup up the write buffer. */
1787 tcp_write_queue_purge(sk);
1788
1789 /* Cleans up our, hopefully empty, out_of_order_queue. */
1790 __skb_queue_purge(&tp->out_of_order_queue);
1791
1792 #ifdef CONFIG_TCP_MD5SIG
1793 /* Clean up the MD5 key list, if any */
1794 if (tp->md5sig_info) {
1795 tcp_clear_md5_list(sk);
1796 kfree_rcu(tp->md5sig_info, rcu);
1797 tp->md5sig_info = NULL;
1798 }
1799 #endif
1800
1801 /* Clean prequeue, it must be empty really */
1802 __skb_queue_purge(&tp->ucopy.prequeue);
1803
1804 /* Clean up a referenced TCP bind bucket. */
1805 if (inet_csk(sk)->icsk_bind_hash)
1806 inet_put_port(sk);
1807
1808 BUG_ON(tp->fastopen_rsk);
1809
1810 /* If socket is aborted during connect operation */
1811 tcp_free_fastopen_req(tp);
1812 tcp_saved_syn_free(tp);
1813
1814 sk_sockets_allocated_dec(sk);
1815 sock_release_memcg(sk);
1816 }
1817 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1818
1819 #ifdef CONFIG_PROC_FS
1820 /* Proc filesystem TCP sock list dumping. */
1821
1822 /*
1823 * Get next listener socket follow cur. If cur is NULL, get first socket
1824 * starting from bucket given in st->bucket; when st->bucket is zero the
1825 * very first socket in the hash table is returned.
1826 */
1827 static void *listening_get_next(struct seq_file *seq, void *cur)
1828 {
1829 struct inet_connection_sock *icsk;
1830 struct hlist_nulls_node *node;
1831 struct sock *sk = cur;
1832 struct inet_listen_hashbucket *ilb;
1833 struct tcp_iter_state *st = seq->private;
1834 struct net *net = seq_file_net(seq);
1835
1836 if (!sk) {
1837 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1838 spin_lock_bh(&ilb->lock);
1839 sk = sk_nulls_head(&ilb->head);
1840 st->offset = 0;
1841 goto get_sk;
1842 }
1843 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1844 ++st->num;
1845 ++st->offset;
1846
1847 sk = sk_nulls_next(sk);
1848 get_sk:
1849 sk_nulls_for_each_from(sk, node) {
1850 if (!net_eq(sock_net(sk), net))
1851 continue;
1852 if (sk->sk_family == st->family) {
1853 cur = sk;
1854 goto out;
1855 }
1856 icsk = inet_csk(sk);
1857 }
1858 spin_unlock_bh(&ilb->lock);
1859 st->offset = 0;
1860 if (++st->bucket < INET_LHTABLE_SIZE) {
1861 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1862 spin_lock_bh(&ilb->lock);
1863 sk = sk_nulls_head(&ilb->head);
1864 goto get_sk;
1865 }
1866 cur = NULL;
1867 out:
1868 return cur;
1869 }
1870
1871 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1872 {
1873 struct tcp_iter_state *st = seq->private;
1874 void *rc;
1875
1876 st->bucket = 0;
1877 st->offset = 0;
1878 rc = listening_get_next(seq, NULL);
1879
1880 while (rc && *pos) {
1881 rc = listening_get_next(seq, rc);
1882 --*pos;
1883 }
1884 return rc;
1885 }
1886
1887 static inline bool empty_bucket(const struct tcp_iter_state *st)
1888 {
1889 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1890 }
1891
1892 /*
1893 * Get first established socket starting from bucket given in st->bucket.
1894 * If st->bucket is zero, the very first socket in the hash is returned.
1895 */
1896 static void *established_get_first(struct seq_file *seq)
1897 {
1898 struct tcp_iter_state *st = seq->private;
1899 struct net *net = seq_file_net(seq);
1900 void *rc = NULL;
1901
1902 st->offset = 0;
1903 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1904 struct sock *sk;
1905 struct hlist_nulls_node *node;
1906 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1907
1908 /* Lockless fast path for the common case of empty buckets */
1909 if (empty_bucket(st))
1910 continue;
1911
1912 spin_lock_bh(lock);
1913 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1914 if (sk->sk_family != st->family ||
1915 !net_eq(sock_net(sk), net)) {
1916 continue;
1917 }
1918 rc = sk;
1919 goto out;
1920 }
1921 spin_unlock_bh(lock);
1922 }
1923 out:
1924 return rc;
1925 }
1926
1927 static void *established_get_next(struct seq_file *seq, void *cur)
1928 {
1929 struct sock *sk = cur;
1930 struct hlist_nulls_node *node;
1931 struct tcp_iter_state *st = seq->private;
1932 struct net *net = seq_file_net(seq);
1933
1934 ++st->num;
1935 ++st->offset;
1936
1937 sk = sk_nulls_next(sk);
1938
1939 sk_nulls_for_each_from(sk, node) {
1940 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1941 return sk;
1942 }
1943
1944 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1945 ++st->bucket;
1946 return established_get_first(seq);
1947 }
1948
1949 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1950 {
1951 struct tcp_iter_state *st = seq->private;
1952 void *rc;
1953
1954 st->bucket = 0;
1955 rc = established_get_first(seq);
1956
1957 while (rc && pos) {
1958 rc = established_get_next(seq, rc);
1959 --pos;
1960 }
1961 return rc;
1962 }
1963
1964 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1965 {
1966 void *rc;
1967 struct tcp_iter_state *st = seq->private;
1968
1969 st->state = TCP_SEQ_STATE_LISTENING;
1970 rc = listening_get_idx(seq, &pos);
1971
1972 if (!rc) {
1973 st->state = TCP_SEQ_STATE_ESTABLISHED;
1974 rc = established_get_idx(seq, pos);
1975 }
1976
1977 return rc;
1978 }
1979
1980 static void *tcp_seek_last_pos(struct seq_file *seq)
1981 {
1982 struct tcp_iter_state *st = seq->private;
1983 int offset = st->offset;
1984 int orig_num = st->num;
1985 void *rc = NULL;
1986
1987 switch (st->state) {
1988 case TCP_SEQ_STATE_LISTENING:
1989 if (st->bucket >= INET_LHTABLE_SIZE)
1990 break;
1991 st->state = TCP_SEQ_STATE_LISTENING;
1992 rc = listening_get_next(seq, NULL);
1993 while (offset-- && rc)
1994 rc = listening_get_next(seq, rc);
1995 if (rc)
1996 break;
1997 st->bucket = 0;
1998 st->state = TCP_SEQ_STATE_ESTABLISHED;
1999 /* Fallthrough */
2000 case TCP_SEQ_STATE_ESTABLISHED:
2001 if (st->bucket > tcp_hashinfo.ehash_mask)
2002 break;
2003 rc = established_get_first(seq);
2004 while (offset-- && rc)
2005 rc = established_get_next(seq, rc);
2006 }
2007
2008 st->num = orig_num;
2009
2010 return rc;
2011 }
2012
2013 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2014 {
2015 struct tcp_iter_state *st = seq->private;
2016 void *rc;
2017
2018 if (*pos && *pos == st->last_pos) {
2019 rc = tcp_seek_last_pos(seq);
2020 if (rc)
2021 goto out;
2022 }
2023
2024 st->state = TCP_SEQ_STATE_LISTENING;
2025 st->num = 0;
2026 st->bucket = 0;
2027 st->offset = 0;
2028 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2029
2030 out:
2031 st->last_pos = *pos;
2032 return rc;
2033 }
2034
2035 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2036 {
2037 struct tcp_iter_state *st = seq->private;
2038 void *rc = NULL;
2039
2040 if (v == SEQ_START_TOKEN) {
2041 rc = tcp_get_idx(seq, 0);
2042 goto out;
2043 }
2044
2045 switch (st->state) {
2046 case TCP_SEQ_STATE_LISTENING:
2047 rc = listening_get_next(seq, v);
2048 if (!rc) {
2049 st->state = TCP_SEQ_STATE_ESTABLISHED;
2050 st->bucket = 0;
2051 st->offset = 0;
2052 rc = established_get_first(seq);
2053 }
2054 break;
2055 case TCP_SEQ_STATE_ESTABLISHED:
2056 rc = established_get_next(seq, v);
2057 break;
2058 }
2059 out:
2060 ++*pos;
2061 st->last_pos = *pos;
2062 return rc;
2063 }
2064
2065 static void tcp_seq_stop(struct seq_file *seq, void *v)
2066 {
2067 struct tcp_iter_state *st = seq->private;
2068
2069 switch (st->state) {
2070 case TCP_SEQ_STATE_LISTENING:
2071 if (v != SEQ_START_TOKEN)
2072 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2073 break;
2074 case TCP_SEQ_STATE_ESTABLISHED:
2075 if (v)
2076 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2077 break;
2078 }
2079 }
2080
2081 int tcp_seq_open(struct inode *inode, struct file *file)
2082 {
2083 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2084 struct tcp_iter_state *s;
2085 int err;
2086
2087 err = seq_open_net(inode, file, &afinfo->seq_ops,
2088 sizeof(struct tcp_iter_state));
2089 if (err < 0)
2090 return err;
2091
2092 s = ((struct seq_file *)file->private_data)->private;
2093 s->family = afinfo->family;
2094 s->last_pos = 0;
2095 return 0;
2096 }
2097 EXPORT_SYMBOL(tcp_seq_open);
2098
2099 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2100 {
2101 int rc = 0;
2102 struct proc_dir_entry *p;
2103
2104 afinfo->seq_ops.start = tcp_seq_start;
2105 afinfo->seq_ops.next = tcp_seq_next;
2106 afinfo->seq_ops.stop = tcp_seq_stop;
2107
2108 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2109 afinfo->seq_fops, afinfo);
2110 if (!p)
2111 rc = -ENOMEM;
2112 return rc;
2113 }
2114 EXPORT_SYMBOL(tcp_proc_register);
2115
2116 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2117 {
2118 remove_proc_entry(afinfo->name, net->proc_net);
2119 }
2120 EXPORT_SYMBOL(tcp_proc_unregister);
2121
2122 static void get_openreq4(const struct request_sock *req,
2123 struct seq_file *f, int i)
2124 {
2125 const struct inet_request_sock *ireq = inet_rsk(req);
2126 long delta = req->rsk_timer.expires - jiffies;
2127
2128 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2129 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2130 i,
2131 ireq->ir_loc_addr,
2132 ireq->ir_num,
2133 ireq->ir_rmt_addr,
2134 ntohs(ireq->ir_rmt_port),
2135 TCP_SYN_RECV,
2136 0, 0, /* could print option size, but that is af dependent. */
2137 1, /* timers active (only the expire timer) */
2138 jiffies_delta_to_clock_t(delta),
2139 req->num_timeout,
2140 from_kuid_munged(seq_user_ns(f),
2141 sock_i_uid(req->rsk_listener)),
2142 0, /* non standard timer */
2143 0, /* open_requests have no inode */
2144 0,
2145 req);
2146 }
2147
2148 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2149 {
2150 int timer_active;
2151 unsigned long timer_expires;
2152 const struct tcp_sock *tp = tcp_sk(sk);
2153 const struct inet_connection_sock *icsk = inet_csk(sk);
2154 const struct inet_sock *inet = inet_sk(sk);
2155 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2156 __be32 dest = inet->inet_daddr;
2157 __be32 src = inet->inet_rcv_saddr;
2158 __u16 destp = ntohs(inet->inet_dport);
2159 __u16 srcp = ntohs(inet->inet_sport);
2160 int rx_queue;
2161 int state;
2162
2163 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2164 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2165 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2166 timer_active = 1;
2167 timer_expires = icsk->icsk_timeout;
2168 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2169 timer_active = 4;
2170 timer_expires = icsk->icsk_timeout;
2171 } else if (timer_pending(&sk->sk_timer)) {
2172 timer_active = 2;
2173 timer_expires = sk->sk_timer.expires;
2174 } else {
2175 timer_active = 0;
2176 timer_expires = jiffies;
2177 }
2178
2179 state = sk_state_load(sk);
2180 if (state == TCP_LISTEN)
2181 rx_queue = sk->sk_ack_backlog;
2182 else
2183 /* Because we don't lock the socket,
2184 * we might find a transient negative value.
2185 */
2186 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2187
2188 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2189 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2190 i, src, srcp, dest, destp, state,
2191 tp->write_seq - tp->snd_una,
2192 rx_queue,
2193 timer_active,
2194 jiffies_delta_to_clock_t(timer_expires - jiffies),
2195 icsk->icsk_retransmits,
2196 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2197 icsk->icsk_probes_out,
2198 sock_i_ino(sk),
2199 atomic_read(&sk->sk_refcnt), sk,
2200 jiffies_to_clock_t(icsk->icsk_rto),
2201 jiffies_to_clock_t(icsk->icsk_ack.ato),
2202 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2203 tp->snd_cwnd,
2204 state == TCP_LISTEN ?
2205 fastopenq->max_qlen :
2206 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2207 }
2208
2209 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2210 struct seq_file *f, int i)
2211 {
2212 long delta = tw->tw_timer.expires - jiffies;
2213 __be32 dest, src;
2214 __u16 destp, srcp;
2215
2216 dest = tw->tw_daddr;
2217 src = tw->tw_rcv_saddr;
2218 destp = ntohs(tw->tw_dport);
2219 srcp = ntohs(tw->tw_sport);
2220
2221 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2222 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2223 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2224 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2225 atomic_read(&tw->tw_refcnt), tw);
2226 }
2227
2228 #define TMPSZ 150
2229
2230 static int tcp4_seq_show(struct seq_file *seq, void *v)
2231 {
2232 struct tcp_iter_state *st;
2233 struct sock *sk = v;
2234
2235 seq_setwidth(seq, TMPSZ - 1);
2236 if (v == SEQ_START_TOKEN) {
2237 seq_puts(seq, " sl local_address rem_address st tx_queue "
2238 "rx_queue tr tm->when retrnsmt uid timeout "
2239 "inode");
2240 goto out;
2241 }
2242 st = seq->private;
2243
2244 if (sk->sk_state == TCP_TIME_WAIT)
2245 get_timewait4_sock(v, seq, st->num);
2246 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2247 get_openreq4(v, seq, st->num);
2248 else
2249 get_tcp4_sock(v, seq, st->num);
2250 out:
2251 seq_pad(seq, '\n');
2252 return 0;
2253 }
2254
2255 static const struct file_operations tcp_afinfo_seq_fops = {
2256 .owner = THIS_MODULE,
2257 .open = tcp_seq_open,
2258 .read = seq_read,
2259 .llseek = seq_lseek,
2260 .release = seq_release_net
2261 };
2262
2263 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2264 .name = "tcp",
2265 .family = AF_INET,
2266 .seq_fops = &tcp_afinfo_seq_fops,
2267 .seq_ops = {
2268 .show = tcp4_seq_show,
2269 },
2270 };
2271
2272 static int __net_init tcp4_proc_init_net(struct net *net)
2273 {
2274 return tcp_proc_register(net, &tcp4_seq_afinfo);
2275 }
2276
2277 static void __net_exit tcp4_proc_exit_net(struct net *net)
2278 {
2279 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2280 }
2281
2282 static struct pernet_operations tcp4_net_ops = {
2283 .init = tcp4_proc_init_net,
2284 .exit = tcp4_proc_exit_net,
2285 };
2286
2287 int __init tcp4_proc_init(void)
2288 {
2289 return register_pernet_subsys(&tcp4_net_ops);
2290 }
2291
2292 void tcp4_proc_exit(void)
2293 {
2294 unregister_pernet_subsys(&tcp4_net_ops);
2295 }
2296 #endif /* CONFIG_PROC_FS */
2297
2298 struct proto tcp_prot = {
2299 .name = "TCP",
2300 .owner = THIS_MODULE,
2301 .close = tcp_close,
2302 .connect = tcp_v4_connect,
2303 .disconnect = tcp_disconnect,
2304 .accept = inet_csk_accept,
2305 .ioctl = tcp_ioctl,
2306 .init = tcp_v4_init_sock,
2307 .destroy = tcp_v4_destroy_sock,
2308 .shutdown = tcp_shutdown,
2309 .setsockopt = tcp_setsockopt,
2310 .getsockopt = tcp_getsockopt,
2311 .recvmsg = tcp_recvmsg,
2312 .sendmsg = tcp_sendmsg,
2313 .sendpage = tcp_sendpage,
2314 .backlog_rcv = tcp_v4_do_rcv,
2315 .release_cb = tcp_release_cb,
2316 .hash = inet_hash,
2317 .unhash = inet_unhash,
2318 .get_port = inet_csk_get_port,
2319 .enter_memory_pressure = tcp_enter_memory_pressure,
2320 .stream_memory_free = tcp_stream_memory_free,
2321 .sockets_allocated = &tcp_sockets_allocated,
2322 .orphan_count = &tcp_orphan_count,
2323 .memory_allocated = &tcp_memory_allocated,
2324 .memory_pressure = &tcp_memory_pressure,
2325 .sysctl_mem = sysctl_tcp_mem,
2326 .sysctl_wmem = sysctl_tcp_wmem,
2327 .sysctl_rmem = sysctl_tcp_rmem,
2328 .max_header = MAX_TCP_HEADER,
2329 .obj_size = sizeof(struct tcp_sock),
2330 .slab_flags = SLAB_DESTROY_BY_RCU,
2331 .twsk_prot = &tcp_timewait_sock_ops,
2332 .rsk_prot = &tcp_request_sock_ops,
2333 .h.hashinfo = &tcp_hashinfo,
2334 .no_autobind = true,
2335 #ifdef CONFIG_COMPAT
2336 .compat_setsockopt = compat_tcp_setsockopt,
2337 .compat_getsockopt = compat_tcp_getsockopt,
2338 #endif
2339 #ifdef CONFIG_MEMCG_KMEM
2340 .init_cgroup = tcp_init_cgroup,
2341 .destroy_cgroup = tcp_destroy_cgroup,
2342 .proto_cgroup = tcp_proto_cgroup,
2343 #endif
2344 };
2345 EXPORT_SYMBOL(tcp_prot);
2346
2347 static void __net_exit tcp_sk_exit(struct net *net)
2348 {
2349 int cpu;
2350
2351 for_each_possible_cpu(cpu)
2352 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2353 free_percpu(net->ipv4.tcp_sk);
2354 }
2355
2356 static int __net_init tcp_sk_init(struct net *net)
2357 {
2358 int res, cpu;
2359
2360 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2361 if (!net->ipv4.tcp_sk)
2362 return -ENOMEM;
2363
2364 for_each_possible_cpu(cpu) {
2365 struct sock *sk;
2366
2367 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2368 IPPROTO_TCP, net);
2369 if (res)
2370 goto fail;
2371 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2372 }
2373
2374 net->ipv4.sysctl_tcp_ecn = 2;
2375 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2376
2377 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2378 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2379 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2380
2381 return 0;
2382 fail:
2383 tcp_sk_exit(net);
2384
2385 return res;
2386 }
2387
2388 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2389 {
2390 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2391 }
2392
2393 static struct pernet_operations __net_initdata tcp_sk_ops = {
2394 .init = tcp_sk_init,
2395 .exit = tcp_sk_exit,
2396 .exit_batch = tcp_sk_exit_batch,
2397 };
2398
2399 void __init tcp_v4_init(void)
2400 {
2401 inet_hashinfo_init(&tcp_hashinfo);
2402 if (register_pernet_subsys(&tcp_sk_ops))
2403 panic("Failed to create the TCP control socket.\n");
2404 }
Linux with added FPC-III support