Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
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
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79
80#include <crypto/hash.h>
81#include <linux/scatterlist.h>
82
83#include <trace/events/tcp.h>
84
85#ifdef CONFIG_TCP_MD5SIG
86static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
87 __be32 daddr, __be32 saddr, const struct tcphdr *th);
88#endif
89
90struct inet_hashinfo tcp_hashinfo;
91EXPORT_SYMBOL(tcp_hashinfo);
92
93static u32 tcp_v4_init_seq(const struct sk_buff *skb)
94{
95 return secure_tcp_seq(ip_hdr(skb)->daddr,
96 ip_hdr(skb)->saddr,
97 tcp_hdr(skb)->dest,
98 tcp_hdr(skb)->source);
99}
100
101static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
102{
103 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
104}
105
106int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
107{
108 const struct inet_timewait_sock *tw = inet_twsk(sktw);
109 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
110 struct tcp_sock *tp = tcp_sk(sk);
111 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
112
113 if (reuse == 2) {
114 /* Still does not detect *everything* that goes through
115 * lo, since we require a loopback src or dst address
116 * or direct binding to 'lo' interface.
117 */
118 bool loopback = false;
119 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
120 loopback = true;
121#if IS_ENABLED(CONFIG_IPV6)
122 if (tw->tw_family == AF_INET6) {
123 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
124 (ipv6_addr_v4mapped(&tw->tw_v6_daddr) &&
125 (tw->tw_v6_daddr.s6_addr[12] == 127)) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 (ipv6_addr_v4mapped(&tw->tw_v6_rcv_saddr) &&
128 (tw->tw_v6_rcv_saddr.s6_addr[12] == 127)))
129 loopback = true;
130 } else
131#endif
132 {
133 if (ipv4_is_loopback(tw->tw_daddr) ||
134 ipv4_is_loopback(tw->tw_rcv_saddr))
135 loopback = true;
136 }
137 if (!loopback)
138 reuse = 0;
139 }
140
141 /* With PAWS, it is safe from the viewpoint
142 of data integrity. Even without PAWS it is safe provided sequence
143 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
144
145 Actually, the idea is close to VJ's one, only timestamp cache is
146 held not per host, but per port pair and TW bucket is used as state
147 holder.
148
149 If TW bucket has been already destroyed we fall back to VJ's scheme
150 and use initial timestamp retrieved from peer table.
151 */
152 if (tcptw->tw_ts_recent_stamp &&
153 (!twp || (reuse && time_after32(ktime_get_seconds(),
154 tcptw->tw_ts_recent_stamp)))) {
155 /* In case of repair and re-using TIME-WAIT sockets we still
156 * want to be sure that it is safe as above but honor the
157 * sequence numbers and time stamps set as part of the repair
158 * process.
159 *
160 * Without this check re-using a TIME-WAIT socket with TCP
161 * repair would accumulate a -1 on the repair assigned
162 * sequence number. The first time it is reused the sequence
163 * is -1, the second time -2, etc. This fixes that issue
164 * without appearing to create any others.
165 */
166 if (likely(!tp->repair)) {
167 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
168
169 if (!seq)
170 seq = 1;
171 WRITE_ONCE(tp->write_seq, seq);
172 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
173 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
174 }
175 sock_hold(sktw);
176 return 1;
177 }
178
179 return 0;
180}
181EXPORT_SYMBOL_GPL(tcp_twsk_unique);
182
183static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
184 int addr_len)
185{
186 /* This check is replicated from tcp_v4_connect() and intended to
187 * prevent BPF program called below from accessing bytes that are out
188 * of the bound specified by user in addr_len.
189 */
190 if (addr_len < sizeof(struct sockaddr_in))
191 return -EINVAL;
192
193 sock_owned_by_me(sk);
194
195 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
196}
197
198/* This will initiate an outgoing connection. */
199int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
200{
201 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
202 struct inet_sock *inet = inet_sk(sk);
203 struct tcp_sock *tp = tcp_sk(sk);
204 __be16 orig_sport, orig_dport;
205 __be32 daddr, nexthop;
206 struct flowi4 *fl4;
207 struct rtable *rt;
208 int err;
209 struct ip_options_rcu *inet_opt;
210 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
211
212 if (addr_len < sizeof(struct sockaddr_in))
213 return -EINVAL;
214
215 if (usin->sin_family != AF_INET)
216 return -EAFNOSUPPORT;
217
218 nexthop = daddr = usin->sin_addr.s_addr;
219 inet_opt = rcu_dereference_protected(inet->inet_opt,
220 lockdep_sock_is_held(sk));
221 if (inet_opt && inet_opt->opt.srr) {
222 if (!daddr)
223 return -EINVAL;
224 nexthop = inet_opt->opt.faddr;
225 }
226
227 orig_sport = inet->inet_sport;
228 orig_dport = usin->sin_port;
229 fl4 = &inet->cork.fl.u.ip4;
230 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
231 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
232 IPPROTO_TCP,
233 orig_sport, orig_dport, sk);
234 if (IS_ERR(rt)) {
235 err = PTR_ERR(rt);
236 if (err == -ENETUNREACH)
237 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
238 return err;
239 }
240
241 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
242 ip_rt_put(rt);
243 return -ENETUNREACH;
244 }
245
246 if (!inet_opt || !inet_opt->opt.srr)
247 daddr = fl4->daddr;
248
249 if (!inet->inet_saddr)
250 inet->inet_saddr = fl4->saddr;
251 sk_rcv_saddr_set(sk, inet->inet_saddr);
252
253 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
254 /* Reset inherited state */
255 tp->rx_opt.ts_recent = 0;
256 tp->rx_opt.ts_recent_stamp = 0;
257 if (likely(!tp->repair))
258 WRITE_ONCE(tp->write_seq, 0);
259 }
260
261 inet->inet_dport = usin->sin_port;
262 sk_daddr_set(sk, daddr);
263
264 inet_csk(sk)->icsk_ext_hdr_len = 0;
265 if (inet_opt)
266 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
267
268 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
269
270 /* Socket identity is still unknown (sport may be zero).
271 * However we set state to SYN-SENT and not releasing socket
272 * lock select source port, enter ourselves into the hash tables and
273 * complete initialization after this.
274 */
275 tcp_set_state(sk, TCP_SYN_SENT);
276 err = inet_hash_connect(tcp_death_row, sk);
277 if (err)
278 goto failure;
279
280 sk_set_txhash(sk);
281
282 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
283 inet->inet_sport, inet->inet_dport, sk);
284 if (IS_ERR(rt)) {
285 err = PTR_ERR(rt);
286 rt = NULL;
287 goto failure;
288 }
289 /* OK, now commit destination to socket. */
290 sk->sk_gso_type = SKB_GSO_TCPV4;
291 sk_setup_caps(sk, &rt->dst);
292 rt = NULL;
293
294 if (likely(!tp->repair)) {
295 if (!tp->write_seq)
296 WRITE_ONCE(tp->write_seq,
297 secure_tcp_seq(inet->inet_saddr,
298 inet->inet_daddr,
299 inet->inet_sport,
300 usin->sin_port));
301 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
302 inet->inet_saddr,
303 inet->inet_daddr);
304 }
305
306 inet->inet_id = prandom_u32();
307
308 if (tcp_fastopen_defer_connect(sk, &err))
309 return err;
310 if (err)
311 goto failure;
312
313 err = tcp_connect(sk);
314
315 if (err)
316 goto failure;
317
318 return 0;
319
320failure:
321 /*
322 * This unhashes the socket and releases the local port,
323 * if necessary.
324 */
325 tcp_set_state(sk, TCP_CLOSE);
326 ip_rt_put(rt);
327 sk->sk_route_caps = 0;
328 inet->inet_dport = 0;
329 return err;
330}
331EXPORT_SYMBOL(tcp_v4_connect);
332
333/*
334 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
335 * It can be called through tcp_release_cb() if socket was owned by user
336 * at the time tcp_v4_err() was called to handle ICMP message.
337 */
338void tcp_v4_mtu_reduced(struct sock *sk)
339{
340 struct inet_sock *inet = inet_sk(sk);
341 struct dst_entry *dst;
342 u32 mtu;
343
344 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
345 return;
346 mtu = tcp_sk(sk)->mtu_info;
347 dst = inet_csk_update_pmtu(sk, mtu);
348 if (!dst)
349 return;
350
351 /* Something is about to be wrong... Remember soft error
352 * for the case, if this connection will not able to recover.
353 */
354 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
355 sk->sk_err_soft = EMSGSIZE;
356
357 mtu = dst_mtu(dst);
358
359 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
360 ip_sk_accept_pmtu(sk) &&
361 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
362 tcp_sync_mss(sk, mtu);
363
364 /* Resend the TCP packet because it's
365 * clear that the old packet has been
366 * dropped. This is the new "fast" path mtu
367 * discovery.
368 */
369 tcp_simple_retransmit(sk);
370 } /* else let the usual retransmit timer handle it */
371}
372EXPORT_SYMBOL(tcp_v4_mtu_reduced);
373
374static void do_redirect(struct sk_buff *skb, struct sock *sk)
375{
376 struct dst_entry *dst = __sk_dst_check(sk, 0);
377
378 if (dst)
379 dst->ops->redirect(dst, sk, skb);
380}
381
382
383/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
384void tcp_req_err(struct sock *sk, u32 seq, bool abort)
385{
386 struct request_sock *req = inet_reqsk(sk);
387 struct net *net = sock_net(sk);
388
389 /* ICMPs are not backlogged, hence we cannot get
390 * an established socket here.
391 */
392 if (seq != tcp_rsk(req)->snt_isn) {
393 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
394 } else if (abort) {
395 /*
396 * Still in SYN_RECV, just remove it silently.
397 * There is no good way to pass the error to the newly
398 * created socket, and POSIX does not want network
399 * errors returned from accept().
400 */
401 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
402 tcp_listendrop(req->rsk_listener);
403 }
404 reqsk_put(req);
405}
406EXPORT_SYMBOL(tcp_req_err);
407
408/*
409 * This routine is called by the ICMP module when it gets some
410 * sort of error condition. If err < 0 then the socket should
411 * be closed and the error returned to the user. If err > 0
412 * it's just the icmp type << 8 | icmp code. After adjustment
413 * header points to the first 8 bytes of the tcp header. We need
414 * to find the appropriate port.
415 *
416 * The locking strategy used here is very "optimistic". When
417 * someone else accesses the socket the ICMP is just dropped
418 * and for some paths there is no check at all.
419 * A more general error queue to queue errors for later handling
420 * is probably better.
421 *
422 */
423
424int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
425{
426 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
427 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
428 struct inet_connection_sock *icsk;
429 struct tcp_sock *tp;
430 struct inet_sock *inet;
431 const int type = icmp_hdr(icmp_skb)->type;
432 const int code = icmp_hdr(icmp_skb)->code;
433 struct sock *sk;
434 struct sk_buff *skb;
435 struct request_sock *fastopen;
436 u32 seq, snd_una;
437 s32 remaining;
438 u32 delta_us;
439 int err;
440 struct net *net = dev_net(icmp_skb->dev);
441
442 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
443 th->dest, iph->saddr, ntohs(th->source),
444 inet_iif(icmp_skb), 0);
445 if (!sk) {
446 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
447 return -ENOENT;
448 }
449 if (sk->sk_state == TCP_TIME_WAIT) {
450 inet_twsk_put(inet_twsk(sk));
451 return 0;
452 }
453 seq = ntohl(th->seq);
454 if (sk->sk_state == TCP_NEW_SYN_RECV) {
455 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
456 type == ICMP_TIME_EXCEEDED ||
457 (type == ICMP_DEST_UNREACH &&
458 (code == ICMP_NET_UNREACH ||
459 code == ICMP_HOST_UNREACH)));
460 return 0;
461 }
462
463 bh_lock_sock(sk);
464 /* If too many ICMPs get dropped on busy
465 * servers this needs to be solved differently.
466 * We do take care of PMTU discovery (RFC1191) special case :
467 * we can receive locally generated ICMP messages while socket is held.
468 */
469 if (sock_owned_by_user(sk)) {
470 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
471 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
472 }
473 if (sk->sk_state == TCP_CLOSE)
474 goto out;
475
476 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
477 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
478 goto out;
479 }
480
481 icsk = inet_csk(sk);
482 tp = tcp_sk(sk);
483 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
484 fastopen = rcu_dereference(tp->fastopen_rsk);
485 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
486 if (sk->sk_state != TCP_LISTEN &&
487 !between(seq, snd_una, tp->snd_nxt)) {
488 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
489 goto out;
490 }
491
492 switch (type) {
493 case ICMP_REDIRECT:
494 if (!sock_owned_by_user(sk))
495 do_redirect(icmp_skb, sk);
496 goto out;
497 case ICMP_SOURCE_QUENCH:
498 /* Just silently ignore these. */
499 goto out;
500 case ICMP_PARAMETERPROB:
501 err = EPROTO;
502 break;
503 case ICMP_DEST_UNREACH:
504 if (code > NR_ICMP_UNREACH)
505 goto out;
506
507 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
508 /* We are not interested in TCP_LISTEN and open_requests
509 * (SYN-ACKs send out by Linux are always <576bytes so
510 * they should go through unfragmented).
511 */
512 if (sk->sk_state == TCP_LISTEN)
513 goto out;
514
515 tp->mtu_info = info;
516 if (!sock_owned_by_user(sk)) {
517 tcp_v4_mtu_reduced(sk);
518 } else {
519 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
520 sock_hold(sk);
521 }
522 goto out;
523 }
524
525 err = icmp_err_convert[code].errno;
526 /* check if icmp_skb allows revert of backoff
527 * (see draft-zimmermann-tcp-lcd) */
528 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
529 break;
530 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
531 !icsk->icsk_backoff || fastopen)
532 break;
533
534 if (sock_owned_by_user(sk))
535 break;
536
537 skb = tcp_rtx_queue_head(sk);
538 if (WARN_ON_ONCE(!skb))
539 break;
540
541 icsk->icsk_backoff--;
542 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
543 TCP_TIMEOUT_INIT;
544 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
545
546
547 tcp_mstamp_refresh(tp);
548 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
549 remaining = icsk->icsk_rto -
550 usecs_to_jiffies(delta_us);
551
552 if (remaining > 0) {
553 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
554 remaining, TCP_RTO_MAX);
555 } else {
556 /* RTO revert clocked out retransmission.
557 * Will retransmit now */
558 tcp_retransmit_timer(sk);
559 }
560
561 break;
562 case ICMP_TIME_EXCEEDED:
563 err = EHOSTUNREACH;
564 break;
565 default:
566 goto out;
567 }
568
569 switch (sk->sk_state) {
570 case TCP_SYN_SENT:
571 case TCP_SYN_RECV:
572 /* Only in fast or simultaneous open. If a fast open socket is
573 * is already accepted it is treated as a connected one below.
574 */
575 if (fastopen && !fastopen->sk)
576 break;
577
578 if (!sock_owned_by_user(sk)) {
579 sk->sk_err = err;
580
581 sk->sk_error_report(sk);
582
583 tcp_done(sk);
584 } else {
585 sk->sk_err_soft = err;
586 }
587 goto out;
588 }
589
590 /* If we've already connected we will keep trying
591 * until we time out, or the user gives up.
592 *
593 * rfc1122 4.2.3.9 allows to consider as hard errors
594 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
595 * but it is obsoleted by pmtu discovery).
596 *
597 * Note, that in modern internet, where routing is unreliable
598 * and in each dark corner broken firewalls sit, sending random
599 * errors ordered by their masters even this two messages finally lose
600 * their original sense (even Linux sends invalid PORT_UNREACHs)
601 *
602 * Now we are in compliance with RFCs.
603 * --ANK (980905)
604 */
605
606 inet = inet_sk(sk);
607 if (!sock_owned_by_user(sk) && inet->recverr) {
608 sk->sk_err = err;
609 sk->sk_error_report(sk);
610 } else { /* Only an error on timeout */
611 sk->sk_err_soft = err;
612 }
613
614out:
615 bh_unlock_sock(sk);
616 sock_put(sk);
617 return 0;
618}
619
620void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
621{
622 struct tcphdr *th = tcp_hdr(skb);
623
624 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
625 skb->csum_start = skb_transport_header(skb) - skb->head;
626 skb->csum_offset = offsetof(struct tcphdr, check);
627}
628
629/* This routine computes an IPv4 TCP checksum. */
630void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
631{
632 const struct inet_sock *inet = inet_sk(sk);
633
634 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
635}
636EXPORT_SYMBOL(tcp_v4_send_check);
637
638/*
639 * This routine will send an RST to the other tcp.
640 *
641 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
642 * for reset.
643 * Answer: if a packet caused RST, it is not for a socket
644 * existing in our system, if it is matched to a socket,
645 * it is just duplicate segment or bug in other side's TCP.
646 * So that we build reply only basing on parameters
647 * arrived with segment.
648 * Exception: precedence violation. We do not implement it in any case.
649 */
650
651static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
652{
653 const struct tcphdr *th = tcp_hdr(skb);
654 struct {
655 struct tcphdr th;
656#ifdef CONFIG_TCP_MD5SIG
657 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
658#endif
659 } rep;
660 struct ip_reply_arg arg;
661#ifdef CONFIG_TCP_MD5SIG
662 struct tcp_md5sig_key *key = NULL;
663 const __u8 *hash_location = NULL;
664 unsigned char newhash[16];
665 int genhash;
666 struct sock *sk1 = NULL;
667#endif
668 u64 transmit_time = 0;
669 struct sock *ctl_sk;
670 struct net *net;
671
672 /* Never send a reset in response to a reset. */
673 if (th->rst)
674 return;
675
676 /* If sk not NULL, it means we did a successful lookup and incoming
677 * route had to be correct. prequeue might have dropped our dst.
678 */
679 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
680 return;
681
682 /* Swap the send and the receive. */
683 memset(&rep, 0, sizeof(rep));
684 rep.th.dest = th->source;
685 rep.th.source = th->dest;
686 rep.th.doff = sizeof(struct tcphdr) / 4;
687 rep.th.rst = 1;
688
689 if (th->ack) {
690 rep.th.seq = th->ack_seq;
691 } else {
692 rep.th.ack = 1;
693 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
694 skb->len - (th->doff << 2));
695 }
696
697 memset(&arg, 0, sizeof(arg));
698 arg.iov[0].iov_base = (unsigned char *)&rep;
699 arg.iov[0].iov_len = sizeof(rep.th);
700
701 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
702#ifdef CONFIG_TCP_MD5SIG
703 rcu_read_lock();
704 hash_location = tcp_parse_md5sig_option(th);
705 if (sk && sk_fullsock(sk)) {
706 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
707 &ip_hdr(skb)->saddr, AF_INET);
708 } else if (hash_location) {
709 /*
710 * active side is lost. Try to find listening socket through
711 * source port, and then find md5 key through listening socket.
712 * we are not loose security here:
713 * Incoming packet is checked with md5 hash with finding key,
714 * no RST generated if md5 hash doesn't match.
715 */
716 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
717 ip_hdr(skb)->saddr,
718 th->source, ip_hdr(skb)->daddr,
719 ntohs(th->source), inet_iif(skb),
720 tcp_v4_sdif(skb));
721 /* don't send rst if it can't find key */
722 if (!sk1)
723 goto out;
724
725 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
726 &ip_hdr(skb)->saddr, AF_INET);
727 if (!key)
728 goto out;
729
730
731 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
732 if (genhash || memcmp(hash_location, newhash, 16) != 0)
733 goto out;
734
735 }
736
737 if (key) {
738 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
739 (TCPOPT_NOP << 16) |
740 (TCPOPT_MD5SIG << 8) |
741 TCPOLEN_MD5SIG);
742 /* Update length and the length the header thinks exists */
743 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
744 rep.th.doff = arg.iov[0].iov_len / 4;
745
746 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
747 key, ip_hdr(skb)->saddr,
748 ip_hdr(skb)->daddr, &rep.th);
749 }
750#endif
751 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
752 ip_hdr(skb)->saddr, /* XXX */
753 arg.iov[0].iov_len, IPPROTO_TCP, 0);
754 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
755 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
756
757 /* When socket is gone, all binding information is lost.
758 * routing might fail in this case. No choice here, if we choose to force
759 * input interface, we will misroute in case of asymmetric route.
760 */
761 if (sk) {
762 arg.bound_dev_if = sk->sk_bound_dev_if;
763 if (sk_fullsock(sk))
764 trace_tcp_send_reset(sk, skb);
765 }
766
767 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
768 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
769
770 arg.tos = ip_hdr(skb)->tos;
771 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
772 local_bh_disable();
773 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
774 if (sk) {
775 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
776 inet_twsk(sk)->tw_mark : sk->sk_mark;
777 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
778 inet_twsk(sk)->tw_priority : sk->sk_priority;
779 transmit_time = tcp_transmit_time(sk);
780 }
781 ip_send_unicast_reply(ctl_sk,
782 skb, &TCP_SKB_CB(skb)->header.h4.opt,
783 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
784 &arg, arg.iov[0].iov_len,
785 transmit_time);
786
787 ctl_sk->sk_mark = 0;
788 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
789 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
790 local_bh_enable();
791
792#ifdef CONFIG_TCP_MD5SIG
793out:
794 rcu_read_unlock();
795#endif
796}
797
798/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
799 outside socket context is ugly, certainly. What can I do?
800 */
801
802static void tcp_v4_send_ack(const struct sock *sk,
803 struct sk_buff *skb, u32 seq, u32 ack,
804 u32 win, u32 tsval, u32 tsecr, int oif,
805 struct tcp_md5sig_key *key,
806 int reply_flags, u8 tos)
807{
808 const struct tcphdr *th = tcp_hdr(skb);
809 struct {
810 struct tcphdr th;
811 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
812#ifdef CONFIG_TCP_MD5SIG
813 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
814#endif
815 ];
816 } rep;
817 struct net *net = sock_net(sk);
818 struct ip_reply_arg arg;
819 struct sock *ctl_sk;
820 u64 transmit_time;
821
822 memset(&rep.th, 0, sizeof(struct tcphdr));
823 memset(&arg, 0, sizeof(arg));
824
825 arg.iov[0].iov_base = (unsigned char *)&rep;
826 arg.iov[0].iov_len = sizeof(rep.th);
827 if (tsecr) {
828 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
829 (TCPOPT_TIMESTAMP << 8) |
830 TCPOLEN_TIMESTAMP);
831 rep.opt[1] = htonl(tsval);
832 rep.opt[2] = htonl(tsecr);
833 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
834 }
835
836 /* Swap the send and the receive. */
837 rep.th.dest = th->source;
838 rep.th.source = th->dest;
839 rep.th.doff = arg.iov[0].iov_len / 4;
840 rep.th.seq = htonl(seq);
841 rep.th.ack_seq = htonl(ack);
842 rep.th.ack = 1;
843 rep.th.window = htons(win);
844
845#ifdef CONFIG_TCP_MD5SIG
846 if (key) {
847 int offset = (tsecr) ? 3 : 0;
848
849 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
850 (TCPOPT_NOP << 16) |
851 (TCPOPT_MD5SIG << 8) |
852 TCPOLEN_MD5SIG);
853 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
854 rep.th.doff = arg.iov[0].iov_len/4;
855
856 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
857 key, ip_hdr(skb)->saddr,
858 ip_hdr(skb)->daddr, &rep.th);
859 }
860#endif
861 arg.flags = reply_flags;
862 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
863 ip_hdr(skb)->saddr, /* XXX */
864 arg.iov[0].iov_len, IPPROTO_TCP, 0);
865 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
866 if (oif)
867 arg.bound_dev_if = oif;
868 arg.tos = tos;
869 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
870 local_bh_disable();
871 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
872 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
873 inet_twsk(sk)->tw_mark : sk->sk_mark;
874 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
875 inet_twsk(sk)->tw_priority : sk->sk_priority;
876 transmit_time = tcp_transmit_time(sk);
877 ip_send_unicast_reply(ctl_sk,
878 skb, &TCP_SKB_CB(skb)->header.h4.opt,
879 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
880 &arg, arg.iov[0].iov_len,
881 transmit_time);
882
883 ctl_sk->sk_mark = 0;
884 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
885 local_bh_enable();
886}
887
888static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
889{
890 struct inet_timewait_sock *tw = inet_twsk(sk);
891 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
892
893 tcp_v4_send_ack(sk, skb,
894 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
895 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
896 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
897 tcptw->tw_ts_recent,
898 tw->tw_bound_dev_if,
899 tcp_twsk_md5_key(tcptw),
900 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
901 tw->tw_tos
902 );
903
904 inet_twsk_put(tw);
905}
906
907static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
908 struct request_sock *req)
909{
910 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
911 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
912 */
913 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
914 tcp_sk(sk)->snd_nxt;
915
916 /* RFC 7323 2.3
917 * The window field (SEG.WND) of every outgoing segment, with the
918 * exception of <SYN> segments, MUST be right-shifted by
919 * Rcv.Wind.Shift bits:
920 */
921 tcp_v4_send_ack(sk, skb, seq,
922 tcp_rsk(req)->rcv_nxt,
923 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
924 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
925 req->ts_recent,
926 0,
927 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
928 AF_INET),
929 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
930 ip_hdr(skb)->tos);
931}
932
933/*
934 * Send a SYN-ACK after having received a SYN.
935 * This still operates on a request_sock only, not on a big
936 * socket.
937 */
938static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
939 struct flowi *fl,
940 struct request_sock *req,
941 struct tcp_fastopen_cookie *foc,
942 enum tcp_synack_type synack_type)
943{
944 const struct inet_request_sock *ireq = inet_rsk(req);
945 struct flowi4 fl4;
946 int err = -1;
947 struct sk_buff *skb;
948
949 /* First, grab a route. */
950 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
951 return -1;
952
953 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
954
955 if (skb) {
956 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
957
958 rcu_read_lock();
959 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
960 ireq->ir_rmt_addr,
961 rcu_dereference(ireq->ireq_opt));
962 rcu_read_unlock();
963 err = net_xmit_eval(err);
964 }
965
966 return err;
967}
968
969/*
970 * IPv4 request_sock destructor.
971 */
972static void tcp_v4_reqsk_destructor(struct request_sock *req)
973{
974 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
975}
976
977#ifdef CONFIG_TCP_MD5SIG
978/*
979 * RFC2385 MD5 checksumming requires a mapping of
980 * IP address->MD5 Key.
981 * We need to maintain these in the sk structure.
982 */
983
984DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
985EXPORT_SYMBOL(tcp_md5_needed);
986
987/* Find the Key structure for an address. */
988struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk,
989 const union tcp_md5_addr *addr,
990 int family)
991{
992 const struct tcp_sock *tp = tcp_sk(sk);
993 struct tcp_md5sig_key *key;
994 const struct tcp_md5sig_info *md5sig;
995 __be32 mask;
996 struct tcp_md5sig_key *best_match = NULL;
997 bool match;
998
999 /* caller either holds rcu_read_lock() or socket lock */
1000 md5sig = rcu_dereference_check(tp->md5sig_info,
1001 lockdep_sock_is_held(sk));
1002 if (!md5sig)
1003 return NULL;
1004
1005 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
1006 if (key->family != family)
1007 continue;
1008
1009 if (family == AF_INET) {
1010 mask = inet_make_mask(key->prefixlen);
1011 match = (key->addr.a4.s_addr & mask) ==
1012 (addr->a4.s_addr & mask);
1013#if IS_ENABLED(CONFIG_IPV6)
1014 } else if (family == AF_INET6) {
1015 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1016 key->prefixlen);
1017#endif
1018 } else {
1019 match = false;
1020 }
1021
1022 if (match && (!best_match ||
1023 key->prefixlen > best_match->prefixlen))
1024 best_match = key;
1025 }
1026 return best_match;
1027}
1028EXPORT_SYMBOL(__tcp_md5_do_lookup);
1029
1030static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1031 const union tcp_md5_addr *addr,
1032 int family, u8 prefixlen)
1033{
1034 const struct tcp_sock *tp = tcp_sk(sk);
1035 struct tcp_md5sig_key *key;
1036 unsigned int size = sizeof(struct in_addr);
1037 const struct tcp_md5sig_info *md5sig;
1038
1039 /* caller either holds rcu_read_lock() or socket lock */
1040 md5sig = rcu_dereference_check(tp->md5sig_info,
1041 lockdep_sock_is_held(sk));
1042 if (!md5sig)
1043 return NULL;
1044#if IS_ENABLED(CONFIG_IPV6)
1045 if (family == AF_INET6)
1046 size = sizeof(struct in6_addr);
1047#endif
1048 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
1049 if (key->family != family)
1050 continue;
1051 if (!memcmp(&key->addr, addr, size) &&
1052 key->prefixlen == prefixlen)
1053 return key;
1054 }
1055 return NULL;
1056}
1057
1058struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1059 const struct sock *addr_sk)
1060{
1061 const union tcp_md5_addr *addr;
1062
1063 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1064 return tcp_md5_do_lookup(sk, addr, AF_INET);
1065}
1066EXPORT_SYMBOL(tcp_v4_md5_lookup);
1067
1068/* This can be called on a newly created socket, from other files */
1069int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1070 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
1071 gfp_t gfp)
1072{
1073 /* Add Key to the list */
1074 struct tcp_md5sig_key *key;
1075 struct tcp_sock *tp = tcp_sk(sk);
1076 struct tcp_md5sig_info *md5sig;
1077
1078 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1079 if (key) {
1080 /* Pre-existing entry - just update that one. */
1081 memcpy(key->key, newkey, newkeylen);
1082 key->keylen = newkeylen;
1083 return 0;
1084 }
1085
1086 md5sig = rcu_dereference_protected(tp->md5sig_info,
1087 lockdep_sock_is_held(sk));
1088 if (!md5sig) {
1089 md5sig = kmalloc(sizeof(*md5sig), gfp);
1090 if (!md5sig)
1091 return -ENOMEM;
1092
1093 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1094 INIT_HLIST_HEAD(&md5sig->head);
1095 rcu_assign_pointer(tp->md5sig_info, md5sig);
1096 }
1097
1098 key = sock_kmalloc(sk, sizeof(*key), gfp);
1099 if (!key)
1100 return -ENOMEM;
1101 if (!tcp_alloc_md5sig_pool()) {
1102 sock_kfree_s(sk, key, sizeof(*key));
1103 return -ENOMEM;
1104 }
1105
1106 memcpy(key->key, newkey, newkeylen);
1107 key->keylen = newkeylen;
1108 key->family = family;
1109 key->prefixlen = prefixlen;
1110 memcpy(&key->addr, addr,
1111 (family == AF_INET6) ? sizeof(struct in6_addr) :
1112 sizeof(struct in_addr));
1113 hlist_add_head_rcu(&key->node, &md5sig->head);
1114 return 0;
1115}
1116EXPORT_SYMBOL(tcp_md5_do_add);
1117
1118int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1119 u8 prefixlen)
1120{
1121 struct tcp_md5sig_key *key;
1122
1123 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1124 if (!key)
1125 return -ENOENT;
1126 hlist_del_rcu(&key->node);
1127 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1128 kfree_rcu(key, rcu);
1129 return 0;
1130}
1131EXPORT_SYMBOL(tcp_md5_do_del);
1132
1133static void tcp_clear_md5_list(struct sock *sk)
1134{
1135 struct tcp_sock *tp = tcp_sk(sk);
1136 struct tcp_md5sig_key *key;
1137 struct hlist_node *n;
1138 struct tcp_md5sig_info *md5sig;
1139
1140 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1141
1142 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1143 hlist_del_rcu(&key->node);
1144 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1145 kfree_rcu(key, rcu);
1146 }
1147}
1148
1149static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1150 char __user *optval, int optlen)
1151{
1152 struct tcp_md5sig cmd;
1153 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1154 u8 prefixlen = 32;
1155
1156 if (optlen < sizeof(cmd))
1157 return -EINVAL;
1158
1159 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1160 return -EFAULT;
1161
1162 if (sin->sin_family != AF_INET)
1163 return -EINVAL;
1164
1165 if (optname == TCP_MD5SIG_EXT &&
1166 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1167 prefixlen = cmd.tcpm_prefixlen;
1168 if (prefixlen > 32)
1169 return -EINVAL;
1170 }
1171
1172 if (!cmd.tcpm_keylen)
1173 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1174 AF_INET, prefixlen);
1175
1176 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1177 return -EINVAL;
1178
1179 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1180 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen,
1181 GFP_KERNEL);
1182}
1183
1184static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1185 __be32 daddr, __be32 saddr,
1186 const struct tcphdr *th, int nbytes)
1187{
1188 struct tcp4_pseudohdr *bp;
1189 struct scatterlist sg;
1190 struct tcphdr *_th;
1191
1192 bp = hp->scratch;
1193 bp->saddr = saddr;
1194 bp->daddr = daddr;
1195 bp->pad = 0;
1196 bp->protocol = IPPROTO_TCP;
1197 bp->len = cpu_to_be16(nbytes);
1198
1199 _th = (struct tcphdr *)(bp + 1);
1200 memcpy(_th, th, sizeof(*th));
1201 _th->check = 0;
1202
1203 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1204 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1205 sizeof(*bp) + sizeof(*th));
1206 return crypto_ahash_update(hp->md5_req);
1207}
1208
1209static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1210 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1211{
1212 struct tcp_md5sig_pool *hp;
1213 struct ahash_request *req;
1214
1215 hp = tcp_get_md5sig_pool();
1216 if (!hp)
1217 goto clear_hash_noput;
1218 req = hp->md5_req;
1219
1220 if (crypto_ahash_init(req))
1221 goto clear_hash;
1222 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1223 goto clear_hash;
1224 if (tcp_md5_hash_key(hp, key))
1225 goto clear_hash;
1226 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1227 if (crypto_ahash_final(req))
1228 goto clear_hash;
1229
1230 tcp_put_md5sig_pool();
1231 return 0;
1232
1233clear_hash:
1234 tcp_put_md5sig_pool();
1235clear_hash_noput:
1236 memset(md5_hash, 0, 16);
1237 return 1;
1238}
1239
1240int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1241 const struct sock *sk,
1242 const struct sk_buff *skb)
1243{
1244 struct tcp_md5sig_pool *hp;
1245 struct ahash_request *req;
1246 const struct tcphdr *th = tcp_hdr(skb);
1247 __be32 saddr, daddr;
1248
1249 if (sk) { /* valid for establish/request sockets */
1250 saddr = sk->sk_rcv_saddr;
1251 daddr = sk->sk_daddr;
1252 } else {
1253 const struct iphdr *iph = ip_hdr(skb);
1254 saddr = iph->saddr;
1255 daddr = iph->daddr;
1256 }
1257
1258 hp = tcp_get_md5sig_pool();
1259 if (!hp)
1260 goto clear_hash_noput;
1261 req = hp->md5_req;
1262
1263 if (crypto_ahash_init(req))
1264 goto clear_hash;
1265
1266 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1267 goto clear_hash;
1268 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1269 goto clear_hash;
1270 if (tcp_md5_hash_key(hp, key))
1271 goto clear_hash;
1272 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1273 if (crypto_ahash_final(req))
1274 goto clear_hash;
1275
1276 tcp_put_md5sig_pool();
1277 return 0;
1278
1279clear_hash:
1280 tcp_put_md5sig_pool();
1281clear_hash_noput:
1282 memset(md5_hash, 0, 16);
1283 return 1;
1284}
1285EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1286
1287#endif
1288
1289/* Called with rcu_read_lock() */
1290static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1291 const struct sk_buff *skb)
1292{
1293#ifdef CONFIG_TCP_MD5SIG
1294 /*
1295 * This gets called for each TCP segment that arrives
1296 * so we want to be efficient.
1297 * We have 3 drop cases:
1298 * o No MD5 hash and one expected.
1299 * o MD5 hash and we're not expecting one.
1300 * o MD5 hash and its wrong.
1301 */
1302 const __u8 *hash_location = NULL;
1303 struct tcp_md5sig_key *hash_expected;
1304 const struct iphdr *iph = ip_hdr(skb);
1305 const struct tcphdr *th = tcp_hdr(skb);
1306 int genhash;
1307 unsigned char newhash[16];
1308
1309 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1310 AF_INET);
1311 hash_location = tcp_parse_md5sig_option(th);
1312
1313 /* We've parsed the options - do we have a hash? */
1314 if (!hash_expected && !hash_location)
1315 return false;
1316
1317 if (hash_expected && !hash_location) {
1318 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1319 return true;
1320 }
1321
1322 if (!hash_expected && hash_location) {
1323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1324 return true;
1325 }
1326
1327 /* Okay, so this is hash_expected and hash_location -
1328 * so we need to calculate the checksum.
1329 */
1330 genhash = tcp_v4_md5_hash_skb(newhash,
1331 hash_expected,
1332 NULL, skb);
1333
1334 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1335 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1336 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1337 &iph->saddr, ntohs(th->source),
1338 &iph->daddr, ntohs(th->dest),
1339 genhash ? " tcp_v4_calc_md5_hash failed"
1340 : "");
1341 return true;
1342 }
1343 return false;
1344#endif
1345 return false;
1346}
1347
1348static void tcp_v4_init_req(struct request_sock *req,
1349 const struct sock *sk_listener,
1350 struct sk_buff *skb)
1351{
1352 struct inet_request_sock *ireq = inet_rsk(req);
1353 struct net *net = sock_net(sk_listener);
1354
1355 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1356 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1357 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1358}
1359
1360static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1361 struct flowi *fl,
1362 const struct request_sock *req)
1363{
1364 return inet_csk_route_req(sk, &fl->u.ip4, req);
1365}
1366
1367struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1368 .family = PF_INET,
1369 .obj_size = sizeof(struct tcp_request_sock),
1370 .rtx_syn_ack = tcp_rtx_synack,
1371 .send_ack = tcp_v4_reqsk_send_ack,
1372 .destructor = tcp_v4_reqsk_destructor,
1373 .send_reset = tcp_v4_send_reset,
1374 .syn_ack_timeout = tcp_syn_ack_timeout,
1375};
1376
1377static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1378 .mss_clamp = TCP_MSS_DEFAULT,
1379#ifdef CONFIG_TCP_MD5SIG
1380 .req_md5_lookup = tcp_v4_md5_lookup,
1381 .calc_md5_hash = tcp_v4_md5_hash_skb,
1382#endif
1383 .init_req = tcp_v4_init_req,
1384#ifdef CONFIG_SYN_COOKIES
1385 .cookie_init_seq = cookie_v4_init_sequence,
1386#endif
1387 .route_req = tcp_v4_route_req,
1388 .init_seq = tcp_v4_init_seq,
1389 .init_ts_off = tcp_v4_init_ts_off,
1390 .send_synack = tcp_v4_send_synack,
1391};
1392
1393int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1394{
1395 /* Never answer to SYNs send to broadcast or multicast */
1396 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1397 goto drop;
1398
1399 return tcp_conn_request(&tcp_request_sock_ops,
1400 &tcp_request_sock_ipv4_ops, sk, skb);
1401
1402drop:
1403 tcp_listendrop(sk);
1404 return 0;
1405}
1406EXPORT_SYMBOL(tcp_v4_conn_request);
1407
1408
1409/*
1410 * The three way handshake has completed - we got a valid synack -
1411 * now create the new socket.
1412 */
1413struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1414 struct request_sock *req,
1415 struct dst_entry *dst,
1416 struct request_sock *req_unhash,
1417 bool *own_req)
1418{
1419 struct inet_request_sock *ireq;
1420 struct inet_sock *newinet;
1421 struct tcp_sock *newtp;
1422 struct sock *newsk;
1423#ifdef CONFIG_TCP_MD5SIG
1424 struct tcp_md5sig_key *key;
1425#endif
1426 struct ip_options_rcu *inet_opt;
1427
1428 if (sk_acceptq_is_full(sk))
1429 goto exit_overflow;
1430
1431 newsk = tcp_create_openreq_child(sk, req, skb);
1432 if (!newsk)
1433 goto exit_nonewsk;
1434
1435 newsk->sk_gso_type = SKB_GSO_TCPV4;
1436 inet_sk_rx_dst_set(newsk, skb);
1437
1438 newtp = tcp_sk(newsk);
1439 newinet = inet_sk(newsk);
1440 ireq = inet_rsk(req);
1441 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1442 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1443 newsk->sk_bound_dev_if = ireq->ir_iif;
1444 newinet->inet_saddr = ireq->ir_loc_addr;
1445 inet_opt = rcu_dereference(ireq->ireq_opt);
1446 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1447 newinet->mc_index = inet_iif(skb);
1448 newinet->mc_ttl = ip_hdr(skb)->ttl;
1449 newinet->rcv_tos = ip_hdr(skb)->tos;
1450 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1451 if (inet_opt)
1452 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1453 newinet->inet_id = prandom_u32();
1454
1455 if (!dst) {
1456 dst = inet_csk_route_child_sock(sk, newsk, req);
1457 if (!dst)
1458 goto put_and_exit;
1459 } else {
1460 /* syncookie case : see end of cookie_v4_check() */
1461 }
1462 sk_setup_caps(newsk, dst);
1463
1464 tcp_ca_openreq_child(newsk, dst);
1465
1466 tcp_sync_mss(newsk, dst_mtu(dst));
1467 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1468
1469 tcp_initialize_rcv_mss(newsk);
1470
1471#ifdef CONFIG_TCP_MD5SIG
1472 /* Copy over the MD5 key from the original socket */
1473 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1474 AF_INET);
1475 if (key) {
1476 /*
1477 * We're using one, so create a matching key
1478 * on the newsk structure. If we fail to get
1479 * memory, then we end up not copying the key
1480 * across. Shucks.
1481 */
1482 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1483 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
1484 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1485 }
1486#endif
1487
1488 if (__inet_inherit_port(sk, newsk) < 0)
1489 goto put_and_exit;
1490 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1491 if (likely(*own_req)) {
1492 tcp_move_syn(newtp, req);
1493 ireq->ireq_opt = NULL;
1494 } else {
1495 newinet->inet_opt = NULL;
1496 }
1497 return newsk;
1498
1499exit_overflow:
1500 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1501exit_nonewsk:
1502 dst_release(dst);
1503exit:
1504 tcp_listendrop(sk);
1505 return NULL;
1506put_and_exit:
1507 newinet->inet_opt = NULL;
1508 inet_csk_prepare_forced_close(newsk);
1509 tcp_done(newsk);
1510 goto exit;
1511}
1512EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1513
1514static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1515{
1516#ifdef CONFIG_SYN_COOKIES
1517 const struct tcphdr *th = tcp_hdr(skb);
1518
1519 if (!th->syn)
1520 sk = cookie_v4_check(sk, skb);
1521#endif
1522 return sk;
1523}
1524
1525u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1526 struct tcphdr *th, u32 *cookie)
1527{
1528 u16 mss = 0;
1529#ifdef CONFIG_SYN_COOKIES
1530 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1531 &tcp_request_sock_ipv4_ops, sk, th);
1532 if (mss) {
1533 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1534 tcp_synq_overflow(sk);
1535 }
1536#endif
1537 return mss;
1538}
1539
1540/* The socket must have it's spinlock held when we get
1541 * here, unless it is a TCP_LISTEN socket.
1542 *
1543 * We have a potential double-lock case here, so even when
1544 * doing backlog processing we use the BH locking scheme.
1545 * This is because we cannot sleep with the original spinlock
1546 * held.
1547 */
1548int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1549{
1550 struct sock *rsk;
1551
1552 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1553 struct dst_entry *dst = sk->sk_rx_dst;
1554
1555 sock_rps_save_rxhash(sk, skb);
1556 sk_mark_napi_id(sk, skb);
1557 if (dst) {
1558 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1559 !dst->ops->check(dst, 0)) {
1560 dst_release(dst);
1561 sk->sk_rx_dst = NULL;
1562 }
1563 }
1564 tcp_rcv_established(sk, skb);
1565 return 0;
1566 }
1567
1568 if (tcp_checksum_complete(skb))
1569 goto csum_err;
1570
1571 if (sk->sk_state == TCP_LISTEN) {
1572 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1573
1574 if (!nsk)
1575 goto discard;
1576 if (nsk != sk) {
1577 if (tcp_child_process(sk, nsk, skb)) {
1578 rsk = nsk;
1579 goto reset;
1580 }
1581 return 0;
1582 }
1583 } else
1584 sock_rps_save_rxhash(sk, skb);
1585
1586 if (tcp_rcv_state_process(sk, skb)) {
1587 rsk = sk;
1588 goto reset;
1589 }
1590 return 0;
1591
1592reset:
1593 tcp_v4_send_reset(rsk, skb);
1594discard:
1595 kfree_skb(skb);
1596 /* Be careful here. If this function gets more complicated and
1597 * gcc suffers from register pressure on the x86, sk (in %ebx)
1598 * might be destroyed here. This current version compiles correctly,
1599 * but you have been warned.
1600 */
1601 return 0;
1602
1603csum_err:
1604 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1605 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1606 goto discard;
1607}
1608EXPORT_SYMBOL(tcp_v4_do_rcv);
1609
1610int tcp_v4_early_demux(struct sk_buff *skb)
1611{
1612 const struct iphdr *iph;
1613 const struct tcphdr *th;
1614 struct sock *sk;
1615
1616 if (skb->pkt_type != PACKET_HOST)
1617 return 0;
1618
1619 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1620 return 0;
1621
1622 iph = ip_hdr(skb);
1623 th = tcp_hdr(skb);
1624
1625 if (th->doff < sizeof(struct tcphdr) / 4)
1626 return 0;
1627
1628 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1629 iph->saddr, th->source,
1630 iph->daddr, ntohs(th->dest),
1631 skb->skb_iif, inet_sdif(skb));
1632 if (sk) {
1633 skb->sk = sk;
1634 skb->destructor = sock_edemux;
1635 if (sk_fullsock(sk)) {
1636 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1637
1638 if (dst)
1639 dst = dst_check(dst, 0);
1640 if (dst &&
1641 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1642 skb_dst_set_noref(skb, dst);
1643 }
1644 }
1645 return 0;
1646}
1647
1648bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1649{
1650 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1651 struct skb_shared_info *shinfo;
1652 const struct tcphdr *th;
1653 struct tcphdr *thtail;
1654 struct sk_buff *tail;
1655 unsigned int hdrlen;
1656 bool fragstolen;
1657 u32 gso_segs;
1658 int delta;
1659
1660 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1661 * we can fix skb->truesize to its real value to avoid future drops.
1662 * This is valid because skb is not yet charged to the socket.
1663 * It has been noticed pure SACK packets were sometimes dropped
1664 * (if cooked by drivers without copybreak feature).
1665 */
1666 skb_condense(skb);
1667
1668 skb_dst_drop(skb);
1669
1670 if (unlikely(tcp_checksum_complete(skb))) {
1671 bh_unlock_sock(sk);
1672 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1673 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1674 return true;
1675 }
1676
1677 /* Attempt coalescing to last skb in backlog, even if we are
1678 * above the limits.
1679 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1680 */
1681 th = (const struct tcphdr *)skb->data;
1682 hdrlen = th->doff * 4;
1683 shinfo = skb_shinfo(skb);
1684
1685 if (!shinfo->gso_size)
1686 shinfo->gso_size = skb->len - hdrlen;
1687
1688 if (!shinfo->gso_segs)
1689 shinfo->gso_segs = 1;
1690
1691 tail = sk->sk_backlog.tail;
1692 if (!tail)
1693 goto no_coalesce;
1694 thtail = (struct tcphdr *)tail->data;
1695
1696 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1697 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1698 ((TCP_SKB_CB(tail)->tcp_flags |
1699 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1700 !((TCP_SKB_CB(tail)->tcp_flags &
1701 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1702 ((TCP_SKB_CB(tail)->tcp_flags ^
1703 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1704#ifdef CONFIG_TLS_DEVICE
1705 tail->decrypted != skb->decrypted ||
1706#endif
1707 thtail->doff != th->doff ||
1708 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1709 goto no_coalesce;
1710
1711 __skb_pull(skb, hdrlen);
1712 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1713 thtail->window = th->window;
1714
1715 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1716
1717 if (after(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))
1718 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1719
1720 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1721 * thtail->fin, so that the fast path in tcp_rcv_established()
1722 * is not entered if we append a packet with a FIN.
1723 * SYN, RST, URG are not present.
1724 * ACK is set on both packets.
1725 * PSH : we do not really care in TCP stack,
1726 * at least for 'GRO' packets.
1727 */
1728 thtail->fin |= th->fin;
1729 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1730
1731 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1732 TCP_SKB_CB(tail)->has_rxtstamp = true;
1733 tail->tstamp = skb->tstamp;
1734 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1735 }
1736
1737 /* Not as strict as GRO. We only need to carry mss max value */
1738 skb_shinfo(tail)->gso_size = max(shinfo->gso_size,
1739 skb_shinfo(tail)->gso_size);
1740
1741 gso_segs = skb_shinfo(tail)->gso_segs + shinfo->gso_segs;
1742 skb_shinfo(tail)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
1743
1744 sk->sk_backlog.len += delta;
1745 __NET_INC_STATS(sock_net(sk),
1746 LINUX_MIB_TCPBACKLOGCOALESCE);
1747 kfree_skb_partial(skb, fragstolen);
1748 return false;
1749 }
1750 __skb_push(skb, hdrlen);
1751
1752no_coalesce:
1753 /* Only socket owner can try to collapse/prune rx queues
1754 * to reduce memory overhead, so add a little headroom here.
1755 * Few sockets backlog are possibly concurrently non empty.
1756 */
1757 limit += 64*1024;
1758
1759 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1760 bh_unlock_sock(sk);
1761 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1762 return true;
1763 }
1764 return false;
1765}
1766EXPORT_SYMBOL(tcp_add_backlog);
1767
1768int tcp_filter(struct sock *sk, struct sk_buff *skb)
1769{
1770 struct tcphdr *th = (struct tcphdr *)skb->data;
1771
1772 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1773}
1774EXPORT_SYMBOL(tcp_filter);
1775
1776static void tcp_v4_restore_cb(struct sk_buff *skb)
1777{
1778 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1779 sizeof(struct inet_skb_parm));
1780}
1781
1782static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1783 const struct tcphdr *th)
1784{
1785 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1786 * barrier() makes sure compiler wont play fool^Waliasing games.
1787 */
1788 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1789 sizeof(struct inet_skb_parm));
1790 barrier();
1791
1792 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1793 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1794 skb->len - th->doff * 4);
1795 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1796 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1797 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1798 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1799 TCP_SKB_CB(skb)->sacked = 0;
1800 TCP_SKB_CB(skb)->has_rxtstamp =
1801 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1802}
1803
1804/*
1805 * From tcp_input.c
1806 */
1807
1808int tcp_v4_rcv(struct sk_buff *skb)
1809{
1810 struct net *net = dev_net(skb->dev);
1811 struct sk_buff *skb_to_free;
1812 int sdif = inet_sdif(skb);
1813 const struct iphdr *iph;
1814 const struct tcphdr *th;
1815 bool refcounted;
1816 struct sock *sk;
1817 int ret;
1818
1819 if (skb->pkt_type != PACKET_HOST)
1820 goto discard_it;
1821
1822 /* Count it even if it's bad */
1823 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1824
1825 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1826 goto discard_it;
1827
1828 th = (const struct tcphdr *)skb->data;
1829
1830 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1831 goto bad_packet;
1832 if (!pskb_may_pull(skb, th->doff * 4))
1833 goto discard_it;
1834
1835 /* An explanation is required here, I think.
1836 * Packet length and doff are validated by header prediction,
1837 * provided case of th->doff==0 is eliminated.
1838 * So, we defer the checks. */
1839
1840 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1841 goto csum_error;
1842
1843 th = (const struct tcphdr *)skb->data;
1844 iph = ip_hdr(skb);
1845lookup:
1846 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1847 th->dest, sdif, &refcounted);
1848 if (!sk)
1849 goto no_tcp_socket;
1850
1851process:
1852 if (sk->sk_state == TCP_TIME_WAIT)
1853 goto do_time_wait;
1854
1855 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1856 struct request_sock *req = inet_reqsk(sk);
1857 bool req_stolen = false;
1858 struct sock *nsk;
1859
1860 sk = req->rsk_listener;
1861 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1862 sk_drops_add(sk, skb);
1863 reqsk_put(req);
1864 goto discard_it;
1865 }
1866 if (tcp_checksum_complete(skb)) {
1867 reqsk_put(req);
1868 goto csum_error;
1869 }
1870 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1871 inet_csk_reqsk_queue_drop_and_put(sk, req);
1872 goto lookup;
1873 }
1874 /* We own a reference on the listener, increase it again
1875 * as we might lose it too soon.
1876 */
1877 sock_hold(sk);
1878 refcounted = true;
1879 nsk = NULL;
1880 if (!tcp_filter(sk, skb)) {
1881 th = (const struct tcphdr *)skb->data;
1882 iph = ip_hdr(skb);
1883 tcp_v4_fill_cb(skb, iph, th);
1884 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1885 }
1886 if (!nsk) {
1887 reqsk_put(req);
1888 if (req_stolen) {
1889 /* Another cpu got exclusive access to req
1890 * and created a full blown socket.
1891 * Try to feed this packet to this socket
1892 * instead of discarding it.
1893 */
1894 tcp_v4_restore_cb(skb);
1895 sock_put(sk);
1896 goto lookup;
1897 }
1898 goto discard_and_relse;
1899 }
1900 if (nsk == sk) {
1901 reqsk_put(req);
1902 tcp_v4_restore_cb(skb);
1903 } else if (tcp_child_process(sk, nsk, skb)) {
1904 tcp_v4_send_reset(nsk, skb);
1905 goto discard_and_relse;
1906 } else {
1907 sock_put(sk);
1908 return 0;
1909 }
1910 }
1911 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1912 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1913 goto discard_and_relse;
1914 }
1915
1916 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1917 goto discard_and_relse;
1918
1919 if (tcp_v4_inbound_md5_hash(sk, skb))
1920 goto discard_and_relse;
1921
1922 nf_reset_ct(skb);
1923
1924 if (tcp_filter(sk, skb))
1925 goto discard_and_relse;
1926 th = (const struct tcphdr *)skb->data;
1927 iph = ip_hdr(skb);
1928 tcp_v4_fill_cb(skb, iph, th);
1929
1930 skb->dev = NULL;
1931
1932 if (sk->sk_state == TCP_LISTEN) {
1933 ret = tcp_v4_do_rcv(sk, skb);
1934 goto put_and_return;
1935 }
1936
1937 sk_incoming_cpu_update(sk);
1938
1939 bh_lock_sock_nested(sk);
1940 tcp_segs_in(tcp_sk(sk), skb);
1941 ret = 0;
1942 if (!sock_owned_by_user(sk)) {
1943 skb_to_free = sk->sk_rx_skb_cache;
1944 sk->sk_rx_skb_cache = NULL;
1945 ret = tcp_v4_do_rcv(sk, skb);
1946 } else {
1947 if (tcp_add_backlog(sk, skb))
1948 goto discard_and_relse;
1949 skb_to_free = NULL;
1950 }
1951 bh_unlock_sock(sk);
1952 if (skb_to_free)
1953 __kfree_skb(skb_to_free);
1954
1955put_and_return:
1956 if (refcounted)
1957 sock_put(sk);
1958
1959 return ret;
1960
1961no_tcp_socket:
1962 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1963 goto discard_it;
1964
1965 tcp_v4_fill_cb(skb, iph, th);
1966
1967 if (tcp_checksum_complete(skb)) {
1968csum_error:
1969 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1970bad_packet:
1971 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1972 } else {
1973 tcp_v4_send_reset(NULL, skb);
1974 }
1975
1976discard_it:
1977 /* Discard frame. */
1978 kfree_skb(skb);
1979 return 0;
1980
1981discard_and_relse:
1982 sk_drops_add(sk, skb);
1983 if (refcounted)
1984 sock_put(sk);
1985 goto discard_it;
1986
1987do_time_wait:
1988 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1989 inet_twsk_put(inet_twsk(sk));
1990 goto discard_it;
1991 }
1992
1993 tcp_v4_fill_cb(skb, iph, th);
1994
1995 if (tcp_checksum_complete(skb)) {
1996 inet_twsk_put(inet_twsk(sk));
1997 goto csum_error;
1998 }
1999 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2000 case TCP_TW_SYN: {
2001 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2002 &tcp_hashinfo, skb,
2003 __tcp_hdrlen(th),
2004 iph->saddr, th->source,
2005 iph->daddr, th->dest,
2006 inet_iif(skb),
2007 sdif);
2008 if (sk2) {
2009 inet_twsk_deschedule_put(inet_twsk(sk));
2010 sk = sk2;
2011 tcp_v4_restore_cb(skb);
2012 refcounted = false;
2013 goto process;
2014 }
2015 }
2016 /* to ACK */
2017 /* fall through */
2018 case TCP_TW_ACK:
2019 tcp_v4_timewait_ack(sk, skb);
2020 break;
2021 case TCP_TW_RST:
2022 tcp_v4_send_reset(sk, skb);
2023 inet_twsk_deschedule_put(inet_twsk(sk));
2024 goto discard_it;
2025 case TCP_TW_SUCCESS:;
2026 }
2027 goto discard_it;
2028}
2029
2030static struct timewait_sock_ops tcp_timewait_sock_ops = {
2031 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2032 .twsk_unique = tcp_twsk_unique,
2033 .twsk_destructor= tcp_twsk_destructor,
2034};
2035
2036void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2037{
2038 struct dst_entry *dst = skb_dst(skb);
2039
2040 if (dst && dst_hold_safe(dst)) {
2041 sk->sk_rx_dst = dst;
2042 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2043 }
2044}
2045EXPORT_SYMBOL(inet_sk_rx_dst_set);
2046
2047const struct inet_connection_sock_af_ops ipv4_specific = {
2048 .queue_xmit = ip_queue_xmit,
2049 .send_check = tcp_v4_send_check,
2050 .rebuild_header = inet_sk_rebuild_header,
2051 .sk_rx_dst_set = inet_sk_rx_dst_set,
2052 .conn_request = tcp_v4_conn_request,
2053 .syn_recv_sock = tcp_v4_syn_recv_sock,
2054 .net_header_len = sizeof(struct iphdr),
2055 .setsockopt = ip_setsockopt,
2056 .getsockopt = ip_getsockopt,
2057 .addr2sockaddr = inet_csk_addr2sockaddr,
2058 .sockaddr_len = sizeof(struct sockaddr_in),
2059#ifdef CONFIG_COMPAT
2060 .compat_setsockopt = compat_ip_setsockopt,
2061 .compat_getsockopt = compat_ip_getsockopt,
2062#endif
2063 .mtu_reduced = tcp_v4_mtu_reduced,
2064};
2065EXPORT_SYMBOL(ipv4_specific);
2066
2067#ifdef CONFIG_TCP_MD5SIG
2068static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2069 .md5_lookup = tcp_v4_md5_lookup,
2070 .calc_md5_hash = tcp_v4_md5_hash_skb,
2071 .md5_parse = tcp_v4_parse_md5_keys,
2072};
2073#endif
2074
2075/* NOTE: A lot of things set to zero explicitly by call to
2076 * sk_alloc() so need not be done here.
2077 */
2078static int tcp_v4_init_sock(struct sock *sk)
2079{
2080 struct inet_connection_sock *icsk = inet_csk(sk);
2081
2082 tcp_init_sock(sk);
2083
2084 icsk->icsk_af_ops = &ipv4_specific;
2085
2086#ifdef CONFIG_TCP_MD5SIG
2087 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2088#endif
2089
2090 return 0;
2091}
2092
2093void tcp_v4_destroy_sock(struct sock *sk)
2094{
2095 struct tcp_sock *tp = tcp_sk(sk);
2096
2097 trace_tcp_destroy_sock(sk);
2098
2099 tcp_clear_xmit_timers(sk);
2100
2101 tcp_cleanup_congestion_control(sk);
2102
2103 tcp_cleanup_ulp(sk);
2104
2105 /* Cleanup up the write buffer. */
2106 tcp_write_queue_purge(sk);
2107
2108 /* Check if we want to disable active TFO */
2109 tcp_fastopen_active_disable_ofo_check(sk);
2110
2111 /* Cleans up our, hopefully empty, out_of_order_queue. */
2112 skb_rbtree_purge(&tp->out_of_order_queue);
2113
2114#ifdef CONFIG_TCP_MD5SIG
2115 /* Clean up the MD5 key list, if any */
2116 if (tp->md5sig_info) {
2117 tcp_clear_md5_list(sk);
2118 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2119 tp->md5sig_info = NULL;
2120 }
2121#endif
2122
2123 /* Clean up a referenced TCP bind bucket. */
2124 if (inet_csk(sk)->icsk_bind_hash)
2125 inet_put_port(sk);
2126
2127 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2128
2129 /* If socket is aborted during connect operation */
2130 tcp_free_fastopen_req(tp);
2131 tcp_fastopen_destroy_cipher(sk);
2132 tcp_saved_syn_free(tp);
2133
2134 sk_sockets_allocated_dec(sk);
2135}
2136EXPORT_SYMBOL(tcp_v4_destroy_sock);
2137
2138#ifdef CONFIG_PROC_FS
2139/* Proc filesystem TCP sock list dumping. */
2140
2141/*
2142 * Get next listener socket follow cur. If cur is NULL, get first socket
2143 * starting from bucket given in st->bucket; when st->bucket is zero the
2144 * very first socket in the hash table is returned.
2145 */
2146static void *listening_get_next(struct seq_file *seq, void *cur)
2147{
2148 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2149 struct tcp_iter_state *st = seq->private;
2150 struct net *net = seq_file_net(seq);
2151 struct inet_listen_hashbucket *ilb;
2152 struct sock *sk = cur;
2153
2154 if (!sk) {
2155get_head:
2156 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2157 spin_lock(&ilb->lock);
2158 sk = sk_head(&ilb->head);
2159 st->offset = 0;
2160 goto get_sk;
2161 }
2162 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2163 ++st->num;
2164 ++st->offset;
2165
2166 sk = sk_next(sk);
2167get_sk:
2168 sk_for_each_from(sk) {
2169 if (!net_eq(sock_net(sk), net))
2170 continue;
2171 if (sk->sk_family == afinfo->family)
2172 return sk;
2173 }
2174 spin_unlock(&ilb->lock);
2175 st->offset = 0;
2176 if (++st->bucket < INET_LHTABLE_SIZE)
2177 goto get_head;
2178 return NULL;
2179}
2180
2181static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2182{
2183 struct tcp_iter_state *st = seq->private;
2184 void *rc;
2185
2186 st->bucket = 0;
2187 st->offset = 0;
2188 rc = listening_get_next(seq, NULL);
2189
2190 while (rc && *pos) {
2191 rc = listening_get_next(seq, rc);
2192 --*pos;
2193 }
2194 return rc;
2195}
2196
2197static inline bool empty_bucket(const struct tcp_iter_state *st)
2198{
2199 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2200}
2201
2202/*
2203 * Get first established socket starting from bucket given in st->bucket.
2204 * If st->bucket is zero, the very first socket in the hash is returned.
2205 */
2206static void *established_get_first(struct seq_file *seq)
2207{
2208 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2209 struct tcp_iter_state *st = seq->private;
2210 struct net *net = seq_file_net(seq);
2211 void *rc = NULL;
2212
2213 st->offset = 0;
2214 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2215 struct sock *sk;
2216 struct hlist_nulls_node *node;
2217 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2218
2219 /* Lockless fast path for the common case of empty buckets */
2220 if (empty_bucket(st))
2221 continue;
2222
2223 spin_lock_bh(lock);
2224 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2225 if (sk->sk_family != afinfo->family ||
2226 !net_eq(sock_net(sk), net)) {
2227 continue;
2228 }
2229 rc = sk;
2230 goto out;
2231 }
2232 spin_unlock_bh(lock);
2233 }
2234out:
2235 return rc;
2236}
2237
2238static void *established_get_next(struct seq_file *seq, void *cur)
2239{
2240 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2241 struct sock *sk = cur;
2242 struct hlist_nulls_node *node;
2243 struct tcp_iter_state *st = seq->private;
2244 struct net *net = seq_file_net(seq);
2245
2246 ++st->num;
2247 ++st->offset;
2248
2249 sk = sk_nulls_next(sk);
2250
2251 sk_nulls_for_each_from(sk, node) {
2252 if (sk->sk_family == afinfo->family &&
2253 net_eq(sock_net(sk), net))
2254 return sk;
2255 }
2256
2257 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2258 ++st->bucket;
2259 return established_get_first(seq);
2260}
2261
2262static void *established_get_idx(struct seq_file *seq, loff_t pos)
2263{
2264 struct tcp_iter_state *st = seq->private;
2265 void *rc;
2266
2267 st->bucket = 0;
2268 rc = established_get_first(seq);
2269
2270 while (rc && pos) {
2271 rc = established_get_next(seq, rc);
2272 --pos;
2273 }
2274 return rc;
2275}
2276
2277static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2278{
2279 void *rc;
2280 struct tcp_iter_state *st = seq->private;
2281
2282 st->state = TCP_SEQ_STATE_LISTENING;
2283 rc = listening_get_idx(seq, &pos);
2284
2285 if (!rc) {
2286 st->state = TCP_SEQ_STATE_ESTABLISHED;
2287 rc = established_get_idx(seq, pos);
2288 }
2289
2290 return rc;
2291}
2292
2293static void *tcp_seek_last_pos(struct seq_file *seq)
2294{
2295 struct tcp_iter_state *st = seq->private;
2296 int offset = st->offset;
2297 int orig_num = st->num;
2298 void *rc = NULL;
2299
2300 switch (st->state) {
2301 case TCP_SEQ_STATE_LISTENING:
2302 if (st->bucket >= INET_LHTABLE_SIZE)
2303 break;
2304 st->state = TCP_SEQ_STATE_LISTENING;
2305 rc = listening_get_next(seq, NULL);
2306 while (offset-- && rc)
2307 rc = listening_get_next(seq, rc);
2308 if (rc)
2309 break;
2310 st->bucket = 0;
2311 st->state = TCP_SEQ_STATE_ESTABLISHED;
2312 /* Fallthrough */
2313 case TCP_SEQ_STATE_ESTABLISHED:
2314 if (st->bucket > tcp_hashinfo.ehash_mask)
2315 break;
2316 rc = established_get_first(seq);
2317 while (offset-- && rc)
2318 rc = established_get_next(seq, rc);
2319 }
2320
2321 st->num = orig_num;
2322
2323 return rc;
2324}
2325
2326void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2327{
2328 struct tcp_iter_state *st = seq->private;
2329 void *rc;
2330
2331 if (*pos && *pos == st->last_pos) {
2332 rc = tcp_seek_last_pos(seq);
2333 if (rc)
2334 goto out;
2335 }
2336
2337 st->state = TCP_SEQ_STATE_LISTENING;
2338 st->num = 0;
2339 st->bucket = 0;
2340 st->offset = 0;
2341 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2342
2343out:
2344 st->last_pos = *pos;
2345 return rc;
2346}
2347EXPORT_SYMBOL(tcp_seq_start);
2348
2349void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2350{
2351 struct tcp_iter_state *st = seq->private;
2352 void *rc = NULL;
2353
2354 if (v == SEQ_START_TOKEN) {
2355 rc = tcp_get_idx(seq, 0);
2356 goto out;
2357 }
2358
2359 switch (st->state) {
2360 case TCP_SEQ_STATE_LISTENING:
2361 rc = listening_get_next(seq, v);
2362 if (!rc) {
2363 st->state = TCP_SEQ_STATE_ESTABLISHED;
2364 st->bucket = 0;
2365 st->offset = 0;
2366 rc = established_get_first(seq);
2367 }
2368 break;
2369 case TCP_SEQ_STATE_ESTABLISHED:
2370 rc = established_get_next(seq, v);
2371 break;
2372 }
2373out:
2374 ++*pos;
2375 st->last_pos = *pos;
2376 return rc;
2377}
2378EXPORT_SYMBOL(tcp_seq_next);
2379
2380void tcp_seq_stop(struct seq_file *seq, void *v)
2381{
2382 struct tcp_iter_state *st = seq->private;
2383
2384 switch (st->state) {
2385 case TCP_SEQ_STATE_LISTENING:
2386 if (v != SEQ_START_TOKEN)
2387 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2388 break;
2389 case TCP_SEQ_STATE_ESTABLISHED:
2390 if (v)
2391 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2392 break;
2393 }
2394}
2395EXPORT_SYMBOL(tcp_seq_stop);
2396
2397static void get_openreq4(const struct request_sock *req,
2398 struct seq_file *f, int i)
2399{
2400 const struct inet_request_sock *ireq = inet_rsk(req);
2401 long delta = req->rsk_timer.expires - jiffies;
2402
2403 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2404 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2405 i,
2406 ireq->ir_loc_addr,
2407 ireq->ir_num,
2408 ireq->ir_rmt_addr,
2409 ntohs(ireq->ir_rmt_port),
2410 TCP_SYN_RECV,
2411 0, 0, /* could print option size, but that is af dependent. */
2412 1, /* timers active (only the expire timer) */
2413 jiffies_delta_to_clock_t(delta),
2414 req->num_timeout,
2415 from_kuid_munged(seq_user_ns(f),
2416 sock_i_uid(req->rsk_listener)),
2417 0, /* non standard timer */
2418 0, /* open_requests have no inode */
2419 0,
2420 req);
2421}
2422
2423static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2424{
2425 int timer_active;
2426 unsigned long timer_expires;
2427 const struct tcp_sock *tp = tcp_sk(sk);
2428 const struct inet_connection_sock *icsk = inet_csk(sk);
2429 const struct inet_sock *inet = inet_sk(sk);
2430 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2431 __be32 dest = inet->inet_daddr;
2432 __be32 src = inet->inet_rcv_saddr;
2433 __u16 destp = ntohs(inet->inet_dport);
2434 __u16 srcp = ntohs(inet->inet_sport);
2435 int rx_queue;
2436 int state;
2437
2438 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2439 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2440 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2441 timer_active = 1;
2442 timer_expires = icsk->icsk_timeout;
2443 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2444 timer_active = 4;
2445 timer_expires = icsk->icsk_timeout;
2446 } else if (timer_pending(&sk->sk_timer)) {
2447 timer_active = 2;
2448 timer_expires = sk->sk_timer.expires;
2449 } else {
2450 timer_active = 0;
2451 timer_expires = jiffies;
2452 }
2453
2454 state = inet_sk_state_load(sk);
2455 if (state == TCP_LISTEN)
2456 rx_queue = sk->sk_ack_backlog;
2457 else
2458 /* Because we don't lock the socket,
2459 * we might find a transient negative value.
2460 */
2461 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2462 READ_ONCE(tp->copied_seq), 0);
2463
2464 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2465 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2466 i, src, srcp, dest, destp, state,
2467 READ_ONCE(tp->write_seq) - tp->snd_una,
2468 rx_queue,
2469 timer_active,
2470 jiffies_delta_to_clock_t(timer_expires - jiffies),
2471 icsk->icsk_retransmits,
2472 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2473 icsk->icsk_probes_out,
2474 sock_i_ino(sk),
2475 refcount_read(&sk->sk_refcnt), sk,
2476 jiffies_to_clock_t(icsk->icsk_rto),
2477 jiffies_to_clock_t(icsk->icsk_ack.ato),
2478 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2479 tp->snd_cwnd,
2480 state == TCP_LISTEN ?
2481 fastopenq->max_qlen :
2482 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2483}
2484
2485static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2486 struct seq_file *f, int i)
2487{
2488 long delta = tw->tw_timer.expires - jiffies;
2489 __be32 dest, src;
2490 __u16 destp, srcp;
2491
2492 dest = tw->tw_daddr;
2493 src = tw->tw_rcv_saddr;
2494 destp = ntohs(tw->tw_dport);
2495 srcp = ntohs(tw->tw_sport);
2496
2497 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2498 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2499 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2500 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2501 refcount_read(&tw->tw_refcnt), tw);
2502}
2503
2504#define TMPSZ 150
2505
2506static int tcp4_seq_show(struct seq_file *seq, void *v)
2507{
2508 struct tcp_iter_state *st;
2509 struct sock *sk = v;
2510
2511 seq_setwidth(seq, TMPSZ - 1);
2512 if (v == SEQ_START_TOKEN) {
2513 seq_puts(seq, " sl local_address rem_address st tx_queue "
2514 "rx_queue tr tm->when retrnsmt uid timeout "
2515 "inode");
2516 goto out;
2517 }
2518 st = seq->private;
2519
2520 if (sk->sk_state == TCP_TIME_WAIT)
2521 get_timewait4_sock(v, seq, st->num);
2522 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2523 get_openreq4(v, seq, st->num);
2524 else
2525 get_tcp4_sock(v, seq, st->num);
2526out:
2527 seq_pad(seq, '\n');
2528 return 0;
2529}
2530
2531static const struct seq_operations tcp4_seq_ops = {
2532 .show = tcp4_seq_show,
2533 .start = tcp_seq_start,
2534 .next = tcp_seq_next,
2535 .stop = tcp_seq_stop,
2536};
2537
2538static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2539 .family = AF_INET,
2540};
2541
2542static int __net_init tcp4_proc_init_net(struct net *net)
2543{
2544 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2545 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2546 return -ENOMEM;
2547 return 0;
2548}
2549
2550static void __net_exit tcp4_proc_exit_net(struct net *net)
2551{
2552 remove_proc_entry("tcp", net->proc_net);
2553}
2554
2555static struct pernet_operations tcp4_net_ops = {
2556 .init = tcp4_proc_init_net,
2557 .exit = tcp4_proc_exit_net,
2558};
2559
2560int __init tcp4_proc_init(void)
2561{
2562 return register_pernet_subsys(&tcp4_net_ops);
2563}
2564
2565void tcp4_proc_exit(void)
2566{
2567 unregister_pernet_subsys(&tcp4_net_ops);
2568}
2569#endif /* CONFIG_PROC_FS */
2570
2571struct proto tcp_prot = {
2572 .name = "TCP",
2573 .owner = THIS_MODULE,
2574 .close = tcp_close,
2575 .pre_connect = tcp_v4_pre_connect,
2576 .connect = tcp_v4_connect,
2577 .disconnect = tcp_disconnect,
2578 .accept = inet_csk_accept,
2579 .ioctl = tcp_ioctl,
2580 .init = tcp_v4_init_sock,
2581 .destroy = tcp_v4_destroy_sock,
2582 .shutdown = tcp_shutdown,
2583 .setsockopt = tcp_setsockopt,
2584 .getsockopt = tcp_getsockopt,
2585 .keepalive = tcp_set_keepalive,
2586 .recvmsg = tcp_recvmsg,
2587 .sendmsg = tcp_sendmsg,
2588 .sendpage = tcp_sendpage,
2589 .backlog_rcv = tcp_v4_do_rcv,
2590 .release_cb = tcp_release_cb,
2591 .hash = inet_hash,
2592 .unhash = inet_unhash,
2593 .get_port = inet_csk_get_port,
2594 .enter_memory_pressure = tcp_enter_memory_pressure,
2595 .leave_memory_pressure = tcp_leave_memory_pressure,
2596 .stream_memory_free = tcp_stream_memory_free,
2597 .sockets_allocated = &tcp_sockets_allocated,
2598 .orphan_count = &tcp_orphan_count,
2599 .memory_allocated = &tcp_memory_allocated,
2600 .memory_pressure = &tcp_memory_pressure,
2601 .sysctl_mem = sysctl_tcp_mem,
2602 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2603 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2604 .max_header = MAX_TCP_HEADER,
2605 .obj_size = sizeof(struct tcp_sock),
2606 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2607 .twsk_prot = &tcp_timewait_sock_ops,
2608 .rsk_prot = &tcp_request_sock_ops,
2609 .h.hashinfo = &tcp_hashinfo,
2610 .no_autobind = true,
2611#ifdef CONFIG_COMPAT
2612 .compat_setsockopt = compat_tcp_setsockopt,
2613 .compat_getsockopt = compat_tcp_getsockopt,
2614#endif
2615 .diag_destroy = tcp_abort,
2616};
2617EXPORT_SYMBOL(tcp_prot);
2618
2619static void __net_exit tcp_sk_exit(struct net *net)
2620{
2621 int cpu;
2622
2623 if (net->ipv4.tcp_congestion_control)
2624 module_put(net->ipv4.tcp_congestion_control->owner);
2625
2626 for_each_possible_cpu(cpu)
2627 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2628 free_percpu(net->ipv4.tcp_sk);
2629}
2630
2631static int __net_init tcp_sk_init(struct net *net)
2632{
2633 int res, cpu, cnt;
2634
2635 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2636 if (!net->ipv4.tcp_sk)
2637 return -ENOMEM;
2638
2639 for_each_possible_cpu(cpu) {
2640 struct sock *sk;
2641
2642 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2643 IPPROTO_TCP, net);
2644 if (res)
2645 goto fail;
2646 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2647
2648 /* Please enforce IP_DF and IPID==0 for RST and
2649 * ACK sent in SYN-RECV and TIME-WAIT state.
2650 */
2651 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2652
2653 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2654 }
2655
2656 net->ipv4.sysctl_tcp_ecn = 2;
2657 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2658
2659 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2660 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2661 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2662 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2663 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2664
2665 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2666 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2667 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2668
2669 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2670 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2671 net->ipv4.sysctl_tcp_syncookies = 1;
2672 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2673 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2674 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2675 net->ipv4.sysctl_tcp_orphan_retries = 0;
2676 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2677 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2678 net->ipv4.sysctl_tcp_tw_reuse = 2;
2679
2680 cnt = tcp_hashinfo.ehash_mask + 1;
2681 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2682 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2683
2684 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2685 net->ipv4.sysctl_tcp_sack = 1;
2686 net->ipv4.sysctl_tcp_window_scaling = 1;
2687 net->ipv4.sysctl_tcp_timestamps = 1;
2688 net->ipv4.sysctl_tcp_early_retrans = 3;
2689 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2690 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2691 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2692 net->ipv4.sysctl_tcp_max_reordering = 300;
2693 net->ipv4.sysctl_tcp_dsack = 1;
2694 net->ipv4.sysctl_tcp_app_win = 31;
2695 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2696 net->ipv4.sysctl_tcp_frto = 2;
2697 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2698 /* This limits the percentage of the congestion window which we
2699 * will allow a single TSO frame to consume. Building TSO frames
2700 * which are too large can cause TCP streams to be bursty.
2701 */
2702 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2703 /* Default TSQ limit of 16 TSO segments */
2704 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2705 /* rfc5961 challenge ack rate limiting */
2706 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2707 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2708 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2709 net->ipv4.sysctl_tcp_autocorking = 1;
2710 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2711 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2712 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2713 if (net != &init_net) {
2714 memcpy(net->ipv4.sysctl_tcp_rmem,
2715 init_net.ipv4.sysctl_tcp_rmem,
2716 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2717 memcpy(net->ipv4.sysctl_tcp_wmem,
2718 init_net.ipv4.sysctl_tcp_wmem,
2719 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2720 }
2721 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2722 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2723 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2724 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2725 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2726 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2727
2728 /* Reno is always built in */
2729 if (!net_eq(net, &init_net) &&
2730 try_module_get(init_net.ipv4.tcp_congestion_control->owner))
2731 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2732 else
2733 net->ipv4.tcp_congestion_control = &tcp_reno;
2734
2735 return 0;
2736fail:
2737 tcp_sk_exit(net);
2738
2739 return res;
2740}
2741
2742static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2743{
2744 struct net *net;
2745
2746 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2747
2748 list_for_each_entry(net, net_exit_list, exit_list)
2749 tcp_fastopen_ctx_destroy(net);
2750}
2751
2752static struct pernet_operations __net_initdata tcp_sk_ops = {
2753 .init = tcp_sk_init,
2754 .exit = tcp_sk_exit,
2755 .exit_batch = tcp_sk_exit_batch,
2756};
2757
2758void __init tcp_v4_init(void)
2759{
2760 if (register_pernet_subsys(&tcp_sk_ops))
2761 panic("Failed to create the TCP control socket.\n");
2762}
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/busy_poll.h>
77
78#include <linux/inet.h>
79#include <linux/ipv6.h>
80#include <linux/stddef.h>
81#include <linux/proc_fs.h>
82#include <linux/seq_file.h>
83
84#include <crypto/hash.h>
85#include <linux/scatterlist.h>
86
87int sysctl_tcp_low_latency __read_mostly;
88
89#ifdef CONFIG_TCP_MD5SIG
90static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
91 __be32 daddr, __be32 saddr, const struct tcphdr *th);
92#endif
93
94struct inet_hashinfo tcp_hashinfo;
95EXPORT_SYMBOL(tcp_hashinfo);
96
97static u32 tcp_v4_init_sequence(const struct sk_buff *skb, u32 *tsoff)
98{
99 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
100 ip_hdr(skb)->saddr,
101 tcp_hdr(skb)->dest,
102 tcp_hdr(skb)->source, tsoff);
103}
104
105int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
106{
107 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
108 struct tcp_sock *tp = tcp_sk(sk);
109
110 /* With PAWS, it is safe from the viewpoint
111 of data integrity. Even without PAWS it is safe provided sequence
112 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
113
114 Actually, the idea is close to VJ's one, only timestamp cache is
115 held not per host, but per port pair and TW bucket is used as state
116 holder.
117
118 If TW bucket has been already destroyed we fall back to VJ's scheme
119 and use initial timestamp retrieved from peer table.
120 */
121 if (tcptw->tw_ts_recent_stamp &&
122 (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse &&
123 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
124 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
125 if (tp->write_seq == 0)
126 tp->write_seq = 1;
127 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
128 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
129 sock_hold(sktw);
130 return 1;
131 }
132
133 return 0;
134}
135EXPORT_SYMBOL_GPL(tcp_twsk_unique);
136
137/* This will initiate an outgoing connection. */
138int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
139{
140 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
141 struct inet_sock *inet = inet_sk(sk);
142 struct tcp_sock *tp = tcp_sk(sk);
143 __be16 orig_sport, orig_dport;
144 __be32 daddr, nexthop;
145 struct flowi4 *fl4;
146 struct rtable *rt;
147 int err;
148 struct ip_options_rcu *inet_opt;
149
150 if (addr_len < sizeof(struct sockaddr_in))
151 return -EINVAL;
152
153 if (usin->sin_family != AF_INET)
154 return -EAFNOSUPPORT;
155
156 nexthop = daddr = usin->sin_addr.s_addr;
157 inet_opt = rcu_dereference_protected(inet->inet_opt,
158 lockdep_sock_is_held(sk));
159 if (inet_opt && inet_opt->opt.srr) {
160 if (!daddr)
161 return -EINVAL;
162 nexthop = inet_opt->opt.faddr;
163 }
164
165 orig_sport = inet->inet_sport;
166 orig_dport = usin->sin_port;
167 fl4 = &inet->cork.fl.u.ip4;
168 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
169 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
170 IPPROTO_TCP,
171 orig_sport, orig_dport, sk);
172 if (IS_ERR(rt)) {
173 err = PTR_ERR(rt);
174 if (err == -ENETUNREACH)
175 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
176 return err;
177 }
178
179 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
180 ip_rt_put(rt);
181 return -ENETUNREACH;
182 }
183
184 if (!inet_opt || !inet_opt->opt.srr)
185 daddr = fl4->daddr;
186
187 if (!inet->inet_saddr)
188 inet->inet_saddr = fl4->saddr;
189 sk_rcv_saddr_set(sk, inet->inet_saddr);
190
191 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
192 /* Reset inherited state */
193 tp->rx_opt.ts_recent = 0;
194 tp->rx_opt.ts_recent_stamp = 0;
195 if (likely(!tp->repair))
196 tp->write_seq = 0;
197 }
198
199 if (tcp_death_row.sysctl_tw_recycle &&
200 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
201 tcp_fetch_timewait_stamp(sk, &rt->dst);
202
203 inet->inet_dport = usin->sin_port;
204 sk_daddr_set(sk, daddr);
205
206 inet_csk(sk)->icsk_ext_hdr_len = 0;
207 if (inet_opt)
208 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
209
210 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
211
212 /* Socket identity is still unknown (sport may be zero).
213 * However we set state to SYN-SENT and not releasing socket
214 * lock select source port, enter ourselves into the hash tables and
215 * complete initialization after this.
216 */
217 tcp_set_state(sk, TCP_SYN_SENT);
218 err = inet_hash_connect(&tcp_death_row, sk);
219 if (err)
220 goto failure;
221
222 sk_set_txhash(sk);
223
224 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
225 inet->inet_sport, inet->inet_dport, sk);
226 if (IS_ERR(rt)) {
227 err = PTR_ERR(rt);
228 rt = NULL;
229 goto failure;
230 }
231 /* OK, now commit destination to socket. */
232 sk->sk_gso_type = SKB_GSO_TCPV4;
233 sk_setup_caps(sk, &rt->dst);
234
235 if (!tp->write_seq && likely(!tp->repair))
236 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
237 inet->inet_daddr,
238 inet->inet_sport,
239 usin->sin_port,
240 &tp->tsoffset);
241
242 inet->inet_id = tp->write_seq ^ jiffies;
243
244 err = tcp_connect(sk);
245
246 rt = NULL;
247 if (err)
248 goto failure;
249
250 return 0;
251
252failure:
253 /*
254 * This unhashes the socket and releases the local port,
255 * if necessary.
256 */
257 tcp_set_state(sk, TCP_CLOSE);
258 ip_rt_put(rt);
259 sk->sk_route_caps = 0;
260 inet->inet_dport = 0;
261 return err;
262}
263EXPORT_SYMBOL(tcp_v4_connect);
264
265/*
266 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
267 * It can be called through tcp_release_cb() if socket was owned by user
268 * at the time tcp_v4_err() was called to handle ICMP message.
269 */
270void tcp_v4_mtu_reduced(struct sock *sk)
271{
272 struct inet_sock *inet = inet_sk(sk);
273 struct dst_entry *dst;
274 u32 mtu;
275
276 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
277 return;
278 mtu = tcp_sk(sk)->mtu_info;
279 dst = inet_csk_update_pmtu(sk, mtu);
280 if (!dst)
281 return;
282
283 /* Something is about to be wrong... Remember soft error
284 * for the case, if this connection will not able to recover.
285 */
286 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
287 sk->sk_err_soft = EMSGSIZE;
288
289 mtu = dst_mtu(dst);
290
291 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
292 ip_sk_accept_pmtu(sk) &&
293 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
294 tcp_sync_mss(sk, mtu);
295
296 /* Resend the TCP packet because it's
297 * clear that the old packet has been
298 * dropped. This is the new "fast" path mtu
299 * discovery.
300 */
301 tcp_simple_retransmit(sk);
302 } /* else let the usual retransmit timer handle it */
303}
304EXPORT_SYMBOL(tcp_v4_mtu_reduced);
305
306static void do_redirect(struct sk_buff *skb, struct sock *sk)
307{
308 struct dst_entry *dst = __sk_dst_check(sk, 0);
309
310 if (dst)
311 dst->ops->redirect(dst, sk, skb);
312}
313
314
315/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
316void tcp_req_err(struct sock *sk, u32 seq, bool abort)
317{
318 struct request_sock *req = inet_reqsk(sk);
319 struct net *net = sock_net(sk);
320
321 /* ICMPs are not backlogged, hence we cannot get
322 * an established socket here.
323 */
324 if (seq != tcp_rsk(req)->snt_isn) {
325 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
326 } else if (abort) {
327 /*
328 * Still in SYN_RECV, just remove it silently.
329 * There is no good way to pass the error to the newly
330 * created socket, and POSIX does not want network
331 * errors returned from accept().
332 */
333 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
334 tcp_listendrop(req->rsk_listener);
335 }
336 reqsk_put(req);
337}
338EXPORT_SYMBOL(tcp_req_err);
339
340/*
341 * This routine is called by the ICMP module when it gets some
342 * sort of error condition. If err < 0 then the socket should
343 * be closed and the error returned to the user. If err > 0
344 * it's just the icmp type << 8 | icmp code. After adjustment
345 * header points to the first 8 bytes of the tcp header. We need
346 * to find the appropriate port.
347 *
348 * The locking strategy used here is very "optimistic". When
349 * someone else accesses the socket the ICMP is just dropped
350 * and for some paths there is no check at all.
351 * A more general error queue to queue errors for later handling
352 * is probably better.
353 *
354 */
355
356void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
357{
358 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
359 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
360 struct inet_connection_sock *icsk;
361 struct tcp_sock *tp;
362 struct inet_sock *inet;
363 const int type = icmp_hdr(icmp_skb)->type;
364 const int code = icmp_hdr(icmp_skb)->code;
365 struct sock *sk;
366 struct sk_buff *skb;
367 struct request_sock *fastopen;
368 __u32 seq, snd_una;
369 __u32 remaining;
370 int err;
371 struct net *net = dev_net(icmp_skb->dev);
372
373 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
374 th->dest, iph->saddr, ntohs(th->source),
375 inet_iif(icmp_skb));
376 if (!sk) {
377 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
378 return;
379 }
380 if (sk->sk_state == TCP_TIME_WAIT) {
381 inet_twsk_put(inet_twsk(sk));
382 return;
383 }
384 seq = ntohl(th->seq);
385 if (sk->sk_state == TCP_NEW_SYN_RECV)
386 return tcp_req_err(sk, seq,
387 type == ICMP_PARAMETERPROB ||
388 type == ICMP_TIME_EXCEEDED ||
389 (type == ICMP_DEST_UNREACH &&
390 (code == ICMP_NET_UNREACH ||
391 code == ICMP_HOST_UNREACH)));
392
393 bh_lock_sock(sk);
394 /* If too many ICMPs get dropped on busy
395 * servers this needs to be solved differently.
396 * We do take care of PMTU discovery (RFC1191) special case :
397 * we can receive locally generated ICMP messages while socket is held.
398 */
399 if (sock_owned_by_user(sk)) {
400 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
401 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
402 }
403 if (sk->sk_state == TCP_CLOSE)
404 goto out;
405
406 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
407 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
408 goto out;
409 }
410
411 icsk = inet_csk(sk);
412 tp = tcp_sk(sk);
413 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
414 fastopen = tp->fastopen_rsk;
415 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
416 if (sk->sk_state != TCP_LISTEN &&
417 !between(seq, snd_una, tp->snd_nxt)) {
418 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
419 goto out;
420 }
421
422 switch (type) {
423 case ICMP_REDIRECT:
424 if (!sock_owned_by_user(sk))
425 do_redirect(icmp_skb, sk);
426 goto out;
427 case ICMP_SOURCE_QUENCH:
428 /* Just silently ignore these. */
429 goto out;
430 case ICMP_PARAMETERPROB:
431 err = EPROTO;
432 break;
433 case ICMP_DEST_UNREACH:
434 if (code > NR_ICMP_UNREACH)
435 goto out;
436
437 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
438 /* We are not interested in TCP_LISTEN and open_requests
439 * (SYN-ACKs send out by Linux are always <576bytes so
440 * they should go through unfragmented).
441 */
442 if (sk->sk_state == TCP_LISTEN)
443 goto out;
444
445 tp->mtu_info = info;
446 if (!sock_owned_by_user(sk)) {
447 tcp_v4_mtu_reduced(sk);
448 } else {
449 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
450 sock_hold(sk);
451 }
452 goto out;
453 }
454
455 err = icmp_err_convert[code].errno;
456 /* check if icmp_skb allows revert of backoff
457 * (see draft-zimmermann-tcp-lcd) */
458 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
459 break;
460 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
461 !icsk->icsk_backoff || fastopen)
462 break;
463
464 if (sock_owned_by_user(sk))
465 break;
466
467 icsk->icsk_backoff--;
468 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
469 TCP_TIMEOUT_INIT;
470 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
471
472 skb = tcp_write_queue_head(sk);
473 BUG_ON(!skb);
474
475 remaining = icsk->icsk_rto -
476 min(icsk->icsk_rto,
477 tcp_time_stamp - tcp_skb_timestamp(skb));
478
479 if (remaining) {
480 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
481 remaining, TCP_RTO_MAX);
482 } else {
483 /* RTO revert clocked out retransmission.
484 * Will retransmit now */
485 tcp_retransmit_timer(sk);
486 }
487
488 break;
489 case ICMP_TIME_EXCEEDED:
490 err = EHOSTUNREACH;
491 break;
492 default:
493 goto out;
494 }
495
496 switch (sk->sk_state) {
497 case TCP_SYN_SENT:
498 case TCP_SYN_RECV:
499 /* Only in fast or simultaneous open. If a fast open socket is
500 * is already accepted it is treated as a connected one below.
501 */
502 if (fastopen && !fastopen->sk)
503 break;
504
505 if (!sock_owned_by_user(sk)) {
506 sk->sk_err = err;
507
508 sk->sk_error_report(sk);
509
510 tcp_done(sk);
511 } else {
512 sk->sk_err_soft = err;
513 }
514 goto out;
515 }
516
517 /* If we've already connected we will keep trying
518 * until we time out, or the user gives up.
519 *
520 * rfc1122 4.2.3.9 allows to consider as hard errors
521 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
522 * but it is obsoleted by pmtu discovery).
523 *
524 * Note, that in modern internet, where routing is unreliable
525 * and in each dark corner broken firewalls sit, sending random
526 * errors ordered by their masters even this two messages finally lose
527 * their original sense (even Linux sends invalid PORT_UNREACHs)
528 *
529 * Now we are in compliance with RFCs.
530 * --ANK (980905)
531 */
532
533 inet = inet_sk(sk);
534 if (!sock_owned_by_user(sk) && inet->recverr) {
535 sk->sk_err = err;
536 sk->sk_error_report(sk);
537 } else { /* Only an error on timeout */
538 sk->sk_err_soft = err;
539 }
540
541out:
542 bh_unlock_sock(sk);
543 sock_put(sk);
544}
545
546void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
547{
548 struct tcphdr *th = tcp_hdr(skb);
549
550 if (skb->ip_summed == CHECKSUM_PARTIAL) {
551 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
552 skb->csum_start = skb_transport_header(skb) - skb->head;
553 skb->csum_offset = offsetof(struct tcphdr, check);
554 } else {
555 th->check = tcp_v4_check(skb->len, saddr, daddr,
556 csum_partial(th,
557 th->doff << 2,
558 skb->csum));
559 }
560}
561
562/* This routine computes an IPv4 TCP checksum. */
563void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
564{
565 const struct inet_sock *inet = inet_sk(sk);
566
567 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
568}
569EXPORT_SYMBOL(tcp_v4_send_check);
570
571/*
572 * This routine will send an RST to the other tcp.
573 *
574 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
575 * for reset.
576 * Answer: if a packet caused RST, it is not for a socket
577 * existing in our system, if it is matched to a socket,
578 * it is just duplicate segment or bug in other side's TCP.
579 * So that we build reply only basing on parameters
580 * arrived with segment.
581 * Exception: precedence violation. We do not implement it in any case.
582 */
583
584static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
585{
586 const struct tcphdr *th = tcp_hdr(skb);
587 struct {
588 struct tcphdr th;
589#ifdef CONFIG_TCP_MD5SIG
590 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
591#endif
592 } rep;
593 struct ip_reply_arg arg;
594#ifdef CONFIG_TCP_MD5SIG
595 struct tcp_md5sig_key *key = NULL;
596 const __u8 *hash_location = NULL;
597 unsigned char newhash[16];
598 int genhash;
599 struct sock *sk1 = NULL;
600#endif
601 struct net *net;
602
603 /* Never send a reset in response to a reset. */
604 if (th->rst)
605 return;
606
607 /* If sk not NULL, it means we did a successful lookup and incoming
608 * route had to be correct. prequeue might have dropped our dst.
609 */
610 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
611 return;
612
613 /* Swap the send and the receive. */
614 memset(&rep, 0, sizeof(rep));
615 rep.th.dest = th->source;
616 rep.th.source = th->dest;
617 rep.th.doff = sizeof(struct tcphdr) / 4;
618 rep.th.rst = 1;
619
620 if (th->ack) {
621 rep.th.seq = th->ack_seq;
622 } else {
623 rep.th.ack = 1;
624 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
625 skb->len - (th->doff << 2));
626 }
627
628 memset(&arg, 0, sizeof(arg));
629 arg.iov[0].iov_base = (unsigned char *)&rep;
630 arg.iov[0].iov_len = sizeof(rep.th);
631
632 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
633#ifdef CONFIG_TCP_MD5SIG
634 rcu_read_lock();
635 hash_location = tcp_parse_md5sig_option(th);
636 if (sk && sk_fullsock(sk)) {
637 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
638 &ip_hdr(skb)->saddr, AF_INET);
639 } else if (hash_location) {
640 /*
641 * active side is lost. Try to find listening socket through
642 * source port, and then find md5 key through listening socket.
643 * we are not loose security here:
644 * Incoming packet is checked with md5 hash with finding key,
645 * no RST generated if md5 hash doesn't match.
646 */
647 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
648 ip_hdr(skb)->saddr,
649 th->source, ip_hdr(skb)->daddr,
650 ntohs(th->source), inet_iif(skb));
651 /* don't send rst if it can't find key */
652 if (!sk1)
653 goto out;
654
655 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
656 &ip_hdr(skb)->saddr, AF_INET);
657 if (!key)
658 goto out;
659
660
661 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
662 if (genhash || memcmp(hash_location, newhash, 16) != 0)
663 goto out;
664
665 }
666
667 if (key) {
668 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
669 (TCPOPT_NOP << 16) |
670 (TCPOPT_MD5SIG << 8) |
671 TCPOLEN_MD5SIG);
672 /* Update length and the length the header thinks exists */
673 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
674 rep.th.doff = arg.iov[0].iov_len / 4;
675
676 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
677 key, ip_hdr(skb)->saddr,
678 ip_hdr(skb)->daddr, &rep.th);
679 }
680#endif
681 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
682 ip_hdr(skb)->saddr, /* XXX */
683 arg.iov[0].iov_len, IPPROTO_TCP, 0);
684 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
685 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
686
687 /* When socket is gone, all binding information is lost.
688 * routing might fail in this case. No choice here, if we choose to force
689 * input interface, we will misroute in case of asymmetric route.
690 */
691 if (sk)
692 arg.bound_dev_if = sk->sk_bound_dev_if;
693
694 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
695 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
696
697 arg.tos = ip_hdr(skb)->tos;
698 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
699 local_bh_disable();
700 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
701 skb, &TCP_SKB_CB(skb)->header.h4.opt,
702 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
703 &arg, arg.iov[0].iov_len);
704
705 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
706 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
707 local_bh_enable();
708
709#ifdef CONFIG_TCP_MD5SIG
710out:
711 rcu_read_unlock();
712#endif
713}
714
715/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
716 outside socket context is ugly, certainly. What can I do?
717 */
718
719static void tcp_v4_send_ack(const struct sock *sk,
720 struct sk_buff *skb, u32 seq, u32 ack,
721 u32 win, u32 tsval, u32 tsecr, int oif,
722 struct tcp_md5sig_key *key,
723 int reply_flags, u8 tos)
724{
725 const struct tcphdr *th = tcp_hdr(skb);
726 struct {
727 struct tcphdr th;
728 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
729#ifdef CONFIG_TCP_MD5SIG
730 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
731#endif
732 ];
733 } rep;
734 struct net *net = sock_net(sk);
735 struct ip_reply_arg arg;
736
737 memset(&rep.th, 0, sizeof(struct tcphdr));
738 memset(&arg, 0, sizeof(arg));
739
740 arg.iov[0].iov_base = (unsigned char *)&rep;
741 arg.iov[0].iov_len = sizeof(rep.th);
742 if (tsecr) {
743 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
744 (TCPOPT_TIMESTAMP << 8) |
745 TCPOLEN_TIMESTAMP);
746 rep.opt[1] = htonl(tsval);
747 rep.opt[2] = htonl(tsecr);
748 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
749 }
750
751 /* Swap the send and the receive. */
752 rep.th.dest = th->source;
753 rep.th.source = th->dest;
754 rep.th.doff = arg.iov[0].iov_len / 4;
755 rep.th.seq = htonl(seq);
756 rep.th.ack_seq = htonl(ack);
757 rep.th.ack = 1;
758 rep.th.window = htons(win);
759
760#ifdef CONFIG_TCP_MD5SIG
761 if (key) {
762 int offset = (tsecr) ? 3 : 0;
763
764 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
765 (TCPOPT_NOP << 16) |
766 (TCPOPT_MD5SIG << 8) |
767 TCPOLEN_MD5SIG);
768 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
769 rep.th.doff = arg.iov[0].iov_len/4;
770
771 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
772 key, ip_hdr(skb)->saddr,
773 ip_hdr(skb)->daddr, &rep.th);
774 }
775#endif
776 arg.flags = reply_flags;
777 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
778 ip_hdr(skb)->saddr, /* XXX */
779 arg.iov[0].iov_len, IPPROTO_TCP, 0);
780 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
781 if (oif)
782 arg.bound_dev_if = oif;
783 arg.tos = tos;
784 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
785 local_bh_disable();
786 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
787 skb, &TCP_SKB_CB(skb)->header.h4.opt,
788 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
789 &arg, arg.iov[0].iov_len);
790
791 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
792 local_bh_enable();
793}
794
795static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
796{
797 struct inet_timewait_sock *tw = inet_twsk(sk);
798 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
799
800 tcp_v4_send_ack(sk, skb,
801 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
802 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
803 tcp_time_stamp + tcptw->tw_ts_offset,
804 tcptw->tw_ts_recent,
805 tw->tw_bound_dev_if,
806 tcp_twsk_md5_key(tcptw),
807 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
808 tw->tw_tos
809 );
810
811 inet_twsk_put(tw);
812}
813
814static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
815 struct request_sock *req)
816{
817 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
818 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
819 */
820 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
821 tcp_sk(sk)->snd_nxt;
822
823 /* RFC 7323 2.3
824 * The window field (SEG.WND) of every outgoing segment, with the
825 * exception of <SYN> segments, MUST be right-shifted by
826 * Rcv.Wind.Shift bits:
827 */
828 tcp_v4_send_ack(sk, skb, seq,
829 tcp_rsk(req)->rcv_nxt,
830 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
831 tcp_time_stamp + tcp_rsk(req)->ts_off,
832 req->ts_recent,
833 0,
834 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
835 AF_INET),
836 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
837 ip_hdr(skb)->tos);
838}
839
840/*
841 * Send a SYN-ACK after having received a SYN.
842 * This still operates on a request_sock only, not on a big
843 * socket.
844 */
845static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
846 struct flowi *fl,
847 struct request_sock *req,
848 struct tcp_fastopen_cookie *foc,
849 enum tcp_synack_type synack_type)
850{
851 const struct inet_request_sock *ireq = inet_rsk(req);
852 struct flowi4 fl4;
853 int err = -1;
854 struct sk_buff *skb;
855
856 /* First, grab a route. */
857 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
858 return -1;
859
860 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
861
862 if (skb) {
863 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
864
865 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
866 ireq->ir_rmt_addr,
867 ireq->opt);
868 err = net_xmit_eval(err);
869 }
870
871 return err;
872}
873
874/*
875 * IPv4 request_sock destructor.
876 */
877static void tcp_v4_reqsk_destructor(struct request_sock *req)
878{
879 kfree(inet_rsk(req)->opt);
880}
881
882#ifdef CONFIG_TCP_MD5SIG
883/*
884 * RFC2385 MD5 checksumming requires a mapping of
885 * IP address->MD5 Key.
886 * We need to maintain these in the sk structure.
887 */
888
889/* Find the Key structure for an address. */
890struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
891 const union tcp_md5_addr *addr,
892 int family)
893{
894 const struct tcp_sock *tp = tcp_sk(sk);
895 struct tcp_md5sig_key *key;
896 unsigned int size = sizeof(struct in_addr);
897 const struct tcp_md5sig_info *md5sig;
898
899 /* caller either holds rcu_read_lock() or socket lock */
900 md5sig = rcu_dereference_check(tp->md5sig_info,
901 lockdep_sock_is_held(sk));
902 if (!md5sig)
903 return NULL;
904#if IS_ENABLED(CONFIG_IPV6)
905 if (family == AF_INET6)
906 size = sizeof(struct in6_addr);
907#endif
908 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
909 if (key->family != family)
910 continue;
911 if (!memcmp(&key->addr, addr, size))
912 return key;
913 }
914 return NULL;
915}
916EXPORT_SYMBOL(tcp_md5_do_lookup);
917
918struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
919 const struct sock *addr_sk)
920{
921 const union tcp_md5_addr *addr;
922
923 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
924 return tcp_md5_do_lookup(sk, addr, AF_INET);
925}
926EXPORT_SYMBOL(tcp_v4_md5_lookup);
927
928/* This can be called on a newly created socket, from other files */
929int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
930 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
931{
932 /* Add Key to the list */
933 struct tcp_md5sig_key *key;
934 struct tcp_sock *tp = tcp_sk(sk);
935 struct tcp_md5sig_info *md5sig;
936
937 key = tcp_md5_do_lookup(sk, addr, family);
938 if (key) {
939 /* Pre-existing entry - just update that one. */
940 memcpy(key->key, newkey, newkeylen);
941 key->keylen = newkeylen;
942 return 0;
943 }
944
945 md5sig = rcu_dereference_protected(tp->md5sig_info,
946 lockdep_sock_is_held(sk));
947 if (!md5sig) {
948 md5sig = kmalloc(sizeof(*md5sig), gfp);
949 if (!md5sig)
950 return -ENOMEM;
951
952 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
953 INIT_HLIST_HEAD(&md5sig->head);
954 rcu_assign_pointer(tp->md5sig_info, md5sig);
955 }
956
957 key = sock_kmalloc(sk, sizeof(*key), gfp);
958 if (!key)
959 return -ENOMEM;
960 if (!tcp_alloc_md5sig_pool()) {
961 sock_kfree_s(sk, key, sizeof(*key));
962 return -ENOMEM;
963 }
964
965 memcpy(key->key, newkey, newkeylen);
966 key->keylen = newkeylen;
967 key->family = family;
968 memcpy(&key->addr, addr,
969 (family == AF_INET6) ? sizeof(struct in6_addr) :
970 sizeof(struct in_addr));
971 hlist_add_head_rcu(&key->node, &md5sig->head);
972 return 0;
973}
974EXPORT_SYMBOL(tcp_md5_do_add);
975
976int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
977{
978 struct tcp_md5sig_key *key;
979
980 key = tcp_md5_do_lookup(sk, addr, family);
981 if (!key)
982 return -ENOENT;
983 hlist_del_rcu(&key->node);
984 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
985 kfree_rcu(key, rcu);
986 return 0;
987}
988EXPORT_SYMBOL(tcp_md5_do_del);
989
990static void tcp_clear_md5_list(struct sock *sk)
991{
992 struct tcp_sock *tp = tcp_sk(sk);
993 struct tcp_md5sig_key *key;
994 struct hlist_node *n;
995 struct tcp_md5sig_info *md5sig;
996
997 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
998
999 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1000 hlist_del_rcu(&key->node);
1001 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1002 kfree_rcu(key, rcu);
1003 }
1004}
1005
1006static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1007 int optlen)
1008{
1009 struct tcp_md5sig cmd;
1010 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1011
1012 if (optlen < sizeof(cmd))
1013 return -EINVAL;
1014
1015 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1016 return -EFAULT;
1017
1018 if (sin->sin_family != AF_INET)
1019 return -EINVAL;
1020
1021 if (!cmd.tcpm_keylen)
1022 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1023 AF_INET);
1024
1025 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1026 return -EINVAL;
1027
1028 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1029 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1030 GFP_KERNEL);
1031}
1032
1033static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1034 __be32 daddr, __be32 saddr,
1035 const struct tcphdr *th, int nbytes)
1036{
1037 struct tcp4_pseudohdr *bp;
1038 struct scatterlist sg;
1039 struct tcphdr *_th;
1040
1041 bp = hp->scratch;
1042 bp->saddr = saddr;
1043 bp->daddr = daddr;
1044 bp->pad = 0;
1045 bp->protocol = IPPROTO_TCP;
1046 bp->len = cpu_to_be16(nbytes);
1047
1048 _th = (struct tcphdr *)(bp + 1);
1049 memcpy(_th, th, sizeof(*th));
1050 _th->check = 0;
1051
1052 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1053 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1054 sizeof(*bp) + sizeof(*th));
1055 return crypto_ahash_update(hp->md5_req);
1056}
1057
1058static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1059 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1060{
1061 struct tcp_md5sig_pool *hp;
1062 struct ahash_request *req;
1063
1064 hp = tcp_get_md5sig_pool();
1065 if (!hp)
1066 goto clear_hash_noput;
1067 req = hp->md5_req;
1068
1069 if (crypto_ahash_init(req))
1070 goto clear_hash;
1071 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1072 goto clear_hash;
1073 if (tcp_md5_hash_key(hp, key))
1074 goto clear_hash;
1075 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1076 if (crypto_ahash_final(req))
1077 goto clear_hash;
1078
1079 tcp_put_md5sig_pool();
1080 return 0;
1081
1082clear_hash:
1083 tcp_put_md5sig_pool();
1084clear_hash_noput:
1085 memset(md5_hash, 0, 16);
1086 return 1;
1087}
1088
1089int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1090 const struct sock *sk,
1091 const struct sk_buff *skb)
1092{
1093 struct tcp_md5sig_pool *hp;
1094 struct ahash_request *req;
1095 const struct tcphdr *th = tcp_hdr(skb);
1096 __be32 saddr, daddr;
1097
1098 if (sk) { /* valid for establish/request sockets */
1099 saddr = sk->sk_rcv_saddr;
1100 daddr = sk->sk_daddr;
1101 } else {
1102 const struct iphdr *iph = ip_hdr(skb);
1103 saddr = iph->saddr;
1104 daddr = iph->daddr;
1105 }
1106
1107 hp = tcp_get_md5sig_pool();
1108 if (!hp)
1109 goto clear_hash_noput;
1110 req = hp->md5_req;
1111
1112 if (crypto_ahash_init(req))
1113 goto clear_hash;
1114
1115 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1116 goto clear_hash;
1117 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1118 goto clear_hash;
1119 if (tcp_md5_hash_key(hp, key))
1120 goto clear_hash;
1121 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1122 if (crypto_ahash_final(req))
1123 goto clear_hash;
1124
1125 tcp_put_md5sig_pool();
1126 return 0;
1127
1128clear_hash:
1129 tcp_put_md5sig_pool();
1130clear_hash_noput:
1131 memset(md5_hash, 0, 16);
1132 return 1;
1133}
1134EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1135
1136#endif
1137
1138/* Called with rcu_read_lock() */
1139static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1140 const struct sk_buff *skb)
1141{
1142#ifdef CONFIG_TCP_MD5SIG
1143 /*
1144 * This gets called for each TCP segment that arrives
1145 * so we want to be efficient.
1146 * We have 3 drop cases:
1147 * o No MD5 hash and one expected.
1148 * o MD5 hash and we're not expecting one.
1149 * o MD5 hash and its wrong.
1150 */
1151 const __u8 *hash_location = NULL;
1152 struct tcp_md5sig_key *hash_expected;
1153 const struct iphdr *iph = ip_hdr(skb);
1154 const struct tcphdr *th = tcp_hdr(skb);
1155 int genhash;
1156 unsigned char newhash[16];
1157
1158 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1159 AF_INET);
1160 hash_location = tcp_parse_md5sig_option(th);
1161
1162 /* We've parsed the options - do we have a hash? */
1163 if (!hash_expected && !hash_location)
1164 return false;
1165
1166 if (hash_expected && !hash_location) {
1167 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1168 return true;
1169 }
1170
1171 if (!hash_expected && hash_location) {
1172 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1173 return true;
1174 }
1175
1176 /* Okay, so this is hash_expected and hash_location -
1177 * so we need to calculate the checksum.
1178 */
1179 genhash = tcp_v4_md5_hash_skb(newhash,
1180 hash_expected,
1181 NULL, skb);
1182
1183 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1184 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1185 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1186 &iph->saddr, ntohs(th->source),
1187 &iph->daddr, ntohs(th->dest),
1188 genhash ? " tcp_v4_calc_md5_hash failed"
1189 : "");
1190 return true;
1191 }
1192 return false;
1193#endif
1194 return false;
1195}
1196
1197static void tcp_v4_init_req(struct request_sock *req,
1198 const struct sock *sk_listener,
1199 struct sk_buff *skb)
1200{
1201 struct inet_request_sock *ireq = inet_rsk(req);
1202
1203 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1204 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1205 ireq->opt = tcp_v4_save_options(skb);
1206}
1207
1208static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1209 struct flowi *fl,
1210 const struct request_sock *req,
1211 bool *strict)
1212{
1213 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1214
1215 if (strict) {
1216 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1217 *strict = true;
1218 else
1219 *strict = false;
1220 }
1221
1222 return dst;
1223}
1224
1225struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1226 .family = PF_INET,
1227 .obj_size = sizeof(struct tcp_request_sock),
1228 .rtx_syn_ack = tcp_rtx_synack,
1229 .send_ack = tcp_v4_reqsk_send_ack,
1230 .destructor = tcp_v4_reqsk_destructor,
1231 .send_reset = tcp_v4_send_reset,
1232 .syn_ack_timeout = tcp_syn_ack_timeout,
1233};
1234
1235static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1236 .mss_clamp = TCP_MSS_DEFAULT,
1237#ifdef CONFIG_TCP_MD5SIG
1238 .req_md5_lookup = tcp_v4_md5_lookup,
1239 .calc_md5_hash = tcp_v4_md5_hash_skb,
1240#endif
1241 .init_req = tcp_v4_init_req,
1242#ifdef CONFIG_SYN_COOKIES
1243 .cookie_init_seq = cookie_v4_init_sequence,
1244#endif
1245 .route_req = tcp_v4_route_req,
1246 .init_seq = tcp_v4_init_sequence,
1247 .send_synack = tcp_v4_send_synack,
1248};
1249
1250int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1251{
1252 /* Never answer to SYNs send to broadcast or multicast */
1253 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1254 goto drop;
1255
1256 return tcp_conn_request(&tcp_request_sock_ops,
1257 &tcp_request_sock_ipv4_ops, sk, skb);
1258
1259drop:
1260 tcp_listendrop(sk);
1261 return 0;
1262}
1263EXPORT_SYMBOL(tcp_v4_conn_request);
1264
1265
1266/*
1267 * The three way handshake has completed - we got a valid synack -
1268 * now create the new socket.
1269 */
1270struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1271 struct request_sock *req,
1272 struct dst_entry *dst,
1273 struct request_sock *req_unhash,
1274 bool *own_req)
1275{
1276 struct inet_request_sock *ireq;
1277 struct inet_sock *newinet;
1278 struct tcp_sock *newtp;
1279 struct sock *newsk;
1280#ifdef CONFIG_TCP_MD5SIG
1281 struct tcp_md5sig_key *key;
1282#endif
1283 struct ip_options_rcu *inet_opt;
1284
1285 if (sk_acceptq_is_full(sk))
1286 goto exit_overflow;
1287
1288 newsk = tcp_create_openreq_child(sk, req, skb);
1289 if (!newsk)
1290 goto exit_nonewsk;
1291
1292 newsk->sk_gso_type = SKB_GSO_TCPV4;
1293 inet_sk_rx_dst_set(newsk, skb);
1294
1295 newtp = tcp_sk(newsk);
1296 newinet = inet_sk(newsk);
1297 ireq = inet_rsk(req);
1298 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1299 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1300 newsk->sk_bound_dev_if = ireq->ir_iif;
1301 newinet->inet_saddr = ireq->ir_loc_addr;
1302 inet_opt = ireq->opt;
1303 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1304 ireq->opt = NULL;
1305 newinet->mc_index = inet_iif(skb);
1306 newinet->mc_ttl = ip_hdr(skb)->ttl;
1307 newinet->rcv_tos = ip_hdr(skb)->tos;
1308 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1309 if (inet_opt)
1310 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1311 newinet->inet_id = newtp->write_seq ^ jiffies;
1312
1313 if (!dst) {
1314 dst = inet_csk_route_child_sock(sk, newsk, req);
1315 if (!dst)
1316 goto put_and_exit;
1317 } else {
1318 /* syncookie case : see end of cookie_v4_check() */
1319 }
1320 sk_setup_caps(newsk, dst);
1321
1322 tcp_ca_openreq_child(newsk, dst);
1323
1324 tcp_sync_mss(newsk, dst_mtu(dst));
1325 newtp->advmss = dst_metric_advmss(dst);
1326 if (tcp_sk(sk)->rx_opt.user_mss &&
1327 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1328 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1329
1330 tcp_initialize_rcv_mss(newsk);
1331
1332#ifdef CONFIG_TCP_MD5SIG
1333 /* Copy over the MD5 key from the original socket */
1334 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1335 AF_INET);
1336 if (key) {
1337 /*
1338 * We're using one, so create a matching key
1339 * on the newsk structure. If we fail to get
1340 * memory, then we end up not copying the key
1341 * across. Shucks.
1342 */
1343 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1344 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1345 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1346 }
1347#endif
1348
1349 if (__inet_inherit_port(sk, newsk) < 0)
1350 goto put_and_exit;
1351 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1352 if (*own_req)
1353 tcp_move_syn(newtp, req);
1354
1355 return newsk;
1356
1357exit_overflow:
1358 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1359exit_nonewsk:
1360 dst_release(dst);
1361exit:
1362 tcp_listendrop(sk);
1363 return NULL;
1364put_and_exit:
1365 inet_csk_prepare_forced_close(newsk);
1366 tcp_done(newsk);
1367 goto exit;
1368}
1369EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1370
1371static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1372{
1373#ifdef CONFIG_SYN_COOKIES
1374 const struct tcphdr *th = tcp_hdr(skb);
1375
1376 if (!th->syn)
1377 sk = cookie_v4_check(sk, skb);
1378#endif
1379 return sk;
1380}
1381
1382/* The socket must have it's spinlock held when we get
1383 * here, unless it is a TCP_LISTEN socket.
1384 *
1385 * We have a potential double-lock case here, so even when
1386 * doing backlog processing we use the BH locking scheme.
1387 * This is because we cannot sleep with the original spinlock
1388 * held.
1389 */
1390int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1391{
1392 struct sock *rsk;
1393
1394 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1395 struct dst_entry *dst = sk->sk_rx_dst;
1396
1397 sock_rps_save_rxhash(sk, skb);
1398 sk_mark_napi_id(sk, skb);
1399 if (dst) {
1400 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1401 !dst->ops->check(dst, 0)) {
1402 dst_release(dst);
1403 sk->sk_rx_dst = NULL;
1404 }
1405 }
1406 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1407 return 0;
1408 }
1409
1410 if (tcp_checksum_complete(skb))
1411 goto csum_err;
1412
1413 if (sk->sk_state == TCP_LISTEN) {
1414 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1415
1416 if (!nsk)
1417 goto discard;
1418 if (nsk != sk) {
1419 sock_rps_save_rxhash(nsk, skb);
1420 sk_mark_napi_id(nsk, skb);
1421 if (tcp_child_process(sk, nsk, skb)) {
1422 rsk = nsk;
1423 goto reset;
1424 }
1425 return 0;
1426 }
1427 } else
1428 sock_rps_save_rxhash(sk, skb);
1429
1430 if (tcp_rcv_state_process(sk, skb)) {
1431 rsk = sk;
1432 goto reset;
1433 }
1434 return 0;
1435
1436reset:
1437 tcp_v4_send_reset(rsk, skb);
1438discard:
1439 kfree_skb(skb);
1440 /* Be careful here. If this function gets more complicated and
1441 * gcc suffers from register pressure on the x86, sk (in %ebx)
1442 * might be destroyed here. This current version compiles correctly,
1443 * but you have been warned.
1444 */
1445 return 0;
1446
1447csum_err:
1448 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1449 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1450 goto discard;
1451}
1452EXPORT_SYMBOL(tcp_v4_do_rcv);
1453
1454void tcp_v4_early_demux(struct sk_buff *skb)
1455{
1456 const struct iphdr *iph;
1457 const struct tcphdr *th;
1458 struct sock *sk;
1459
1460 if (skb->pkt_type != PACKET_HOST)
1461 return;
1462
1463 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1464 return;
1465
1466 iph = ip_hdr(skb);
1467 th = tcp_hdr(skb);
1468
1469 if (th->doff < sizeof(struct tcphdr) / 4)
1470 return;
1471
1472 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1473 iph->saddr, th->source,
1474 iph->daddr, ntohs(th->dest),
1475 skb->skb_iif);
1476 if (sk) {
1477 skb->sk = sk;
1478 skb->destructor = sock_edemux;
1479 if (sk_fullsock(sk)) {
1480 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1481
1482 if (dst)
1483 dst = dst_check(dst, 0);
1484 if (dst &&
1485 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1486 skb_dst_set_noref(skb, dst);
1487 }
1488 }
1489}
1490
1491/* Packet is added to VJ-style prequeue for processing in process
1492 * context, if a reader task is waiting. Apparently, this exciting
1493 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1494 * failed somewhere. Latency? Burstiness? Well, at least now we will
1495 * see, why it failed. 8)8) --ANK
1496 *
1497 */
1498bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1499{
1500 struct tcp_sock *tp = tcp_sk(sk);
1501
1502 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1503 return false;
1504
1505 if (skb->len <= tcp_hdrlen(skb) &&
1506 skb_queue_len(&tp->ucopy.prequeue) == 0)
1507 return false;
1508
1509 /* Before escaping RCU protected region, we need to take care of skb
1510 * dst. Prequeue is only enabled for established sockets.
1511 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1512 * Instead of doing full sk_rx_dst validity here, let's perform
1513 * an optimistic check.
1514 */
1515 if (likely(sk->sk_rx_dst))
1516 skb_dst_drop(skb);
1517 else
1518 skb_dst_force_safe(skb);
1519
1520 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1521 tp->ucopy.memory += skb->truesize;
1522 if (skb_queue_len(&tp->ucopy.prequeue) >= 32 ||
1523 tp->ucopy.memory + atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) {
1524 struct sk_buff *skb1;
1525
1526 BUG_ON(sock_owned_by_user(sk));
1527 __NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED,
1528 skb_queue_len(&tp->ucopy.prequeue));
1529
1530 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1531 sk_backlog_rcv(sk, skb1);
1532
1533 tp->ucopy.memory = 0;
1534 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1535 wake_up_interruptible_sync_poll(sk_sleep(sk),
1536 POLLIN | POLLRDNORM | POLLRDBAND);
1537 if (!inet_csk_ack_scheduled(sk))
1538 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1539 (3 * tcp_rto_min(sk)) / 4,
1540 TCP_RTO_MAX);
1541 }
1542 return true;
1543}
1544EXPORT_SYMBOL(tcp_prequeue);
1545
1546bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1547{
1548 u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
1549
1550 /* Only socket owner can try to collapse/prune rx queues
1551 * to reduce memory overhead, so add a little headroom here.
1552 * Few sockets backlog are possibly concurrently non empty.
1553 */
1554 limit += 64*1024;
1555
1556 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1557 * we can fix skb->truesize to its real value to avoid future drops.
1558 * This is valid because skb is not yet charged to the socket.
1559 * It has been noticed pure SACK packets were sometimes dropped
1560 * (if cooked by drivers without copybreak feature).
1561 */
1562 if (!skb->data_len)
1563 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
1564
1565 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1566 bh_unlock_sock(sk);
1567 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1568 return true;
1569 }
1570 return false;
1571}
1572EXPORT_SYMBOL(tcp_add_backlog);
1573
1574int tcp_filter(struct sock *sk, struct sk_buff *skb)
1575{
1576 struct tcphdr *th = (struct tcphdr *)skb->data;
1577 unsigned int eaten = skb->len;
1578 int err;
1579
1580 err = sk_filter_trim_cap(sk, skb, th->doff * 4);
1581 if (!err) {
1582 eaten -= skb->len;
1583 TCP_SKB_CB(skb)->end_seq -= eaten;
1584 }
1585 return err;
1586}
1587EXPORT_SYMBOL(tcp_filter);
1588
1589/*
1590 * From tcp_input.c
1591 */
1592
1593int tcp_v4_rcv(struct sk_buff *skb)
1594{
1595 struct net *net = dev_net(skb->dev);
1596 const struct iphdr *iph;
1597 const struct tcphdr *th;
1598 bool refcounted;
1599 struct sock *sk;
1600 int ret;
1601
1602 if (skb->pkt_type != PACKET_HOST)
1603 goto discard_it;
1604
1605 /* Count it even if it's bad */
1606 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1607
1608 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1609 goto discard_it;
1610
1611 th = (const struct tcphdr *)skb->data;
1612
1613 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1614 goto bad_packet;
1615 if (!pskb_may_pull(skb, th->doff * 4))
1616 goto discard_it;
1617
1618 /* An explanation is required here, I think.
1619 * Packet length and doff are validated by header prediction,
1620 * provided case of th->doff==0 is eliminated.
1621 * So, we defer the checks. */
1622
1623 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1624 goto csum_error;
1625
1626 th = (const struct tcphdr *)skb->data;
1627 iph = ip_hdr(skb);
1628 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1629 * barrier() makes sure compiler wont play fool^Waliasing games.
1630 */
1631 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1632 sizeof(struct inet_skb_parm));
1633 barrier();
1634
1635 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1636 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1637 skb->len - th->doff * 4);
1638 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1639 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1640 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1641 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1642 TCP_SKB_CB(skb)->sacked = 0;
1643
1644lookup:
1645 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1646 th->dest, &refcounted);
1647 if (!sk)
1648 goto no_tcp_socket;
1649
1650process:
1651 if (sk->sk_state == TCP_TIME_WAIT)
1652 goto do_time_wait;
1653
1654 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1655 struct request_sock *req = inet_reqsk(sk);
1656 struct sock *nsk;
1657
1658 sk = req->rsk_listener;
1659 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1660 sk_drops_add(sk, skb);
1661 reqsk_put(req);
1662 goto discard_it;
1663 }
1664 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1665 inet_csk_reqsk_queue_drop_and_put(sk, req);
1666 goto lookup;
1667 }
1668 /* We own a reference on the listener, increase it again
1669 * as we might lose it too soon.
1670 */
1671 sock_hold(sk);
1672 refcounted = true;
1673 nsk = tcp_check_req(sk, skb, req, false);
1674 if (!nsk) {
1675 reqsk_put(req);
1676 goto discard_and_relse;
1677 }
1678 if (nsk == sk) {
1679 reqsk_put(req);
1680 } else if (tcp_child_process(sk, nsk, skb)) {
1681 tcp_v4_send_reset(nsk, skb);
1682 goto discard_and_relse;
1683 } else {
1684 sock_put(sk);
1685 return 0;
1686 }
1687 }
1688 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1689 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1690 goto discard_and_relse;
1691 }
1692
1693 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1694 goto discard_and_relse;
1695
1696 if (tcp_v4_inbound_md5_hash(sk, skb))
1697 goto discard_and_relse;
1698
1699 nf_reset(skb);
1700
1701 if (tcp_filter(sk, skb))
1702 goto discard_and_relse;
1703 th = (const struct tcphdr *)skb->data;
1704 iph = ip_hdr(skb);
1705
1706 skb->dev = NULL;
1707
1708 if (sk->sk_state == TCP_LISTEN) {
1709 ret = tcp_v4_do_rcv(sk, skb);
1710 goto put_and_return;
1711 }
1712
1713 sk_incoming_cpu_update(sk);
1714
1715 bh_lock_sock_nested(sk);
1716 tcp_segs_in(tcp_sk(sk), skb);
1717 ret = 0;
1718 if (!sock_owned_by_user(sk)) {
1719 if (!tcp_prequeue(sk, skb))
1720 ret = tcp_v4_do_rcv(sk, skb);
1721 } else if (tcp_add_backlog(sk, skb)) {
1722 goto discard_and_relse;
1723 }
1724 bh_unlock_sock(sk);
1725
1726put_and_return:
1727 if (refcounted)
1728 sock_put(sk);
1729
1730 return ret;
1731
1732no_tcp_socket:
1733 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1734 goto discard_it;
1735
1736 if (tcp_checksum_complete(skb)) {
1737csum_error:
1738 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1739bad_packet:
1740 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1741 } else {
1742 tcp_v4_send_reset(NULL, skb);
1743 }
1744
1745discard_it:
1746 /* Discard frame. */
1747 kfree_skb(skb);
1748 return 0;
1749
1750discard_and_relse:
1751 sk_drops_add(sk, skb);
1752 if (refcounted)
1753 sock_put(sk);
1754 goto discard_it;
1755
1756do_time_wait:
1757 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1758 inet_twsk_put(inet_twsk(sk));
1759 goto discard_it;
1760 }
1761
1762 if (tcp_checksum_complete(skb)) {
1763 inet_twsk_put(inet_twsk(sk));
1764 goto csum_error;
1765 }
1766 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1767 case TCP_TW_SYN: {
1768 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1769 &tcp_hashinfo, skb,
1770 __tcp_hdrlen(th),
1771 iph->saddr, th->source,
1772 iph->daddr, th->dest,
1773 inet_iif(skb));
1774 if (sk2) {
1775 inet_twsk_deschedule_put(inet_twsk(sk));
1776 sk = sk2;
1777 refcounted = false;
1778 goto process;
1779 }
1780 /* Fall through to ACK */
1781 }
1782 case TCP_TW_ACK:
1783 tcp_v4_timewait_ack(sk, skb);
1784 break;
1785 case TCP_TW_RST:
1786 tcp_v4_send_reset(sk, skb);
1787 inet_twsk_deschedule_put(inet_twsk(sk));
1788 goto discard_it;
1789 case TCP_TW_SUCCESS:;
1790 }
1791 goto discard_it;
1792}
1793
1794static struct timewait_sock_ops tcp_timewait_sock_ops = {
1795 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1796 .twsk_unique = tcp_twsk_unique,
1797 .twsk_destructor= tcp_twsk_destructor,
1798};
1799
1800void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1801{
1802 struct dst_entry *dst = skb_dst(skb);
1803
1804 if (dst && dst_hold_safe(dst)) {
1805 sk->sk_rx_dst = dst;
1806 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1807 }
1808}
1809EXPORT_SYMBOL(inet_sk_rx_dst_set);
1810
1811const struct inet_connection_sock_af_ops ipv4_specific = {
1812 .queue_xmit = ip_queue_xmit,
1813 .send_check = tcp_v4_send_check,
1814 .rebuild_header = inet_sk_rebuild_header,
1815 .sk_rx_dst_set = inet_sk_rx_dst_set,
1816 .conn_request = tcp_v4_conn_request,
1817 .syn_recv_sock = tcp_v4_syn_recv_sock,
1818 .net_header_len = sizeof(struct iphdr),
1819 .setsockopt = ip_setsockopt,
1820 .getsockopt = ip_getsockopt,
1821 .addr2sockaddr = inet_csk_addr2sockaddr,
1822 .sockaddr_len = sizeof(struct sockaddr_in),
1823 .bind_conflict = inet_csk_bind_conflict,
1824#ifdef CONFIG_COMPAT
1825 .compat_setsockopt = compat_ip_setsockopt,
1826 .compat_getsockopt = compat_ip_getsockopt,
1827#endif
1828 .mtu_reduced = tcp_v4_mtu_reduced,
1829};
1830EXPORT_SYMBOL(ipv4_specific);
1831
1832#ifdef CONFIG_TCP_MD5SIG
1833static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1834 .md5_lookup = tcp_v4_md5_lookup,
1835 .calc_md5_hash = tcp_v4_md5_hash_skb,
1836 .md5_parse = tcp_v4_parse_md5_keys,
1837};
1838#endif
1839
1840/* NOTE: A lot of things set to zero explicitly by call to
1841 * sk_alloc() so need not be done here.
1842 */
1843static int tcp_v4_init_sock(struct sock *sk)
1844{
1845 struct inet_connection_sock *icsk = inet_csk(sk);
1846
1847 tcp_init_sock(sk);
1848
1849 icsk->icsk_af_ops = &ipv4_specific;
1850
1851#ifdef CONFIG_TCP_MD5SIG
1852 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1853#endif
1854
1855 return 0;
1856}
1857
1858void tcp_v4_destroy_sock(struct sock *sk)
1859{
1860 struct tcp_sock *tp = tcp_sk(sk);
1861
1862 tcp_clear_xmit_timers(sk);
1863
1864 tcp_cleanup_congestion_control(sk);
1865
1866 /* Cleanup up the write buffer. */
1867 tcp_write_queue_purge(sk);
1868
1869 /* Cleans up our, hopefully empty, out_of_order_queue. */
1870 skb_rbtree_purge(&tp->out_of_order_queue);
1871
1872#ifdef CONFIG_TCP_MD5SIG
1873 /* Clean up the MD5 key list, if any */
1874 if (tp->md5sig_info) {
1875 tcp_clear_md5_list(sk);
1876 kfree_rcu(tp->md5sig_info, rcu);
1877 tp->md5sig_info = NULL;
1878 }
1879#endif
1880
1881 /* Clean prequeue, it must be empty really */
1882 __skb_queue_purge(&tp->ucopy.prequeue);
1883
1884 /* Clean up a referenced TCP bind bucket. */
1885 if (inet_csk(sk)->icsk_bind_hash)
1886 inet_put_port(sk);
1887
1888 BUG_ON(tp->fastopen_rsk);
1889
1890 /* If socket is aborted during connect operation */
1891 tcp_free_fastopen_req(tp);
1892 tcp_saved_syn_free(tp);
1893
1894 local_bh_disable();
1895 sk_sockets_allocated_dec(sk);
1896 local_bh_enable();
1897}
1898EXPORT_SYMBOL(tcp_v4_destroy_sock);
1899
1900#ifdef CONFIG_PROC_FS
1901/* Proc filesystem TCP sock list dumping. */
1902
1903/*
1904 * Get next listener socket follow cur. If cur is NULL, get first socket
1905 * starting from bucket given in st->bucket; when st->bucket is zero the
1906 * very first socket in the hash table is returned.
1907 */
1908static void *listening_get_next(struct seq_file *seq, void *cur)
1909{
1910 struct tcp_iter_state *st = seq->private;
1911 struct net *net = seq_file_net(seq);
1912 struct inet_listen_hashbucket *ilb;
1913 struct sock *sk = cur;
1914
1915 if (!sk) {
1916get_head:
1917 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1918 spin_lock(&ilb->lock);
1919 sk = sk_head(&ilb->head);
1920 st->offset = 0;
1921 goto get_sk;
1922 }
1923 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1924 ++st->num;
1925 ++st->offset;
1926
1927 sk = sk_next(sk);
1928get_sk:
1929 sk_for_each_from(sk) {
1930 if (!net_eq(sock_net(sk), net))
1931 continue;
1932 if (sk->sk_family == st->family)
1933 return sk;
1934 }
1935 spin_unlock(&ilb->lock);
1936 st->offset = 0;
1937 if (++st->bucket < INET_LHTABLE_SIZE)
1938 goto get_head;
1939 return NULL;
1940}
1941
1942static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1943{
1944 struct tcp_iter_state *st = seq->private;
1945 void *rc;
1946
1947 st->bucket = 0;
1948 st->offset = 0;
1949 rc = listening_get_next(seq, NULL);
1950
1951 while (rc && *pos) {
1952 rc = listening_get_next(seq, rc);
1953 --*pos;
1954 }
1955 return rc;
1956}
1957
1958static inline bool empty_bucket(const struct tcp_iter_state *st)
1959{
1960 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1961}
1962
1963/*
1964 * Get first established socket starting from bucket given in st->bucket.
1965 * If st->bucket is zero, the very first socket in the hash is returned.
1966 */
1967static void *established_get_first(struct seq_file *seq)
1968{
1969 struct tcp_iter_state *st = seq->private;
1970 struct net *net = seq_file_net(seq);
1971 void *rc = NULL;
1972
1973 st->offset = 0;
1974 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1975 struct sock *sk;
1976 struct hlist_nulls_node *node;
1977 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1978
1979 /* Lockless fast path for the common case of empty buckets */
1980 if (empty_bucket(st))
1981 continue;
1982
1983 spin_lock_bh(lock);
1984 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1985 if (sk->sk_family != st->family ||
1986 !net_eq(sock_net(sk), net)) {
1987 continue;
1988 }
1989 rc = sk;
1990 goto out;
1991 }
1992 spin_unlock_bh(lock);
1993 }
1994out:
1995 return rc;
1996}
1997
1998static void *established_get_next(struct seq_file *seq, void *cur)
1999{
2000 struct sock *sk = cur;
2001 struct hlist_nulls_node *node;
2002 struct tcp_iter_state *st = seq->private;
2003 struct net *net = seq_file_net(seq);
2004
2005 ++st->num;
2006 ++st->offset;
2007
2008 sk = sk_nulls_next(sk);
2009
2010 sk_nulls_for_each_from(sk, node) {
2011 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2012 return sk;
2013 }
2014
2015 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2016 ++st->bucket;
2017 return established_get_first(seq);
2018}
2019
2020static void *established_get_idx(struct seq_file *seq, loff_t pos)
2021{
2022 struct tcp_iter_state *st = seq->private;
2023 void *rc;
2024
2025 st->bucket = 0;
2026 rc = established_get_first(seq);
2027
2028 while (rc && pos) {
2029 rc = established_get_next(seq, rc);
2030 --pos;
2031 }
2032 return rc;
2033}
2034
2035static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2036{
2037 void *rc;
2038 struct tcp_iter_state *st = seq->private;
2039
2040 st->state = TCP_SEQ_STATE_LISTENING;
2041 rc = listening_get_idx(seq, &pos);
2042
2043 if (!rc) {
2044 st->state = TCP_SEQ_STATE_ESTABLISHED;
2045 rc = established_get_idx(seq, pos);
2046 }
2047
2048 return rc;
2049}
2050
2051static void *tcp_seek_last_pos(struct seq_file *seq)
2052{
2053 struct tcp_iter_state *st = seq->private;
2054 int offset = st->offset;
2055 int orig_num = st->num;
2056 void *rc = NULL;
2057
2058 switch (st->state) {
2059 case TCP_SEQ_STATE_LISTENING:
2060 if (st->bucket >= INET_LHTABLE_SIZE)
2061 break;
2062 st->state = TCP_SEQ_STATE_LISTENING;
2063 rc = listening_get_next(seq, NULL);
2064 while (offset-- && rc)
2065 rc = listening_get_next(seq, rc);
2066 if (rc)
2067 break;
2068 st->bucket = 0;
2069 st->state = TCP_SEQ_STATE_ESTABLISHED;
2070 /* Fallthrough */
2071 case TCP_SEQ_STATE_ESTABLISHED:
2072 if (st->bucket > tcp_hashinfo.ehash_mask)
2073 break;
2074 rc = established_get_first(seq);
2075 while (offset-- && rc)
2076 rc = established_get_next(seq, rc);
2077 }
2078
2079 st->num = orig_num;
2080
2081 return rc;
2082}
2083
2084static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2085{
2086 struct tcp_iter_state *st = seq->private;
2087 void *rc;
2088
2089 if (*pos && *pos == st->last_pos) {
2090 rc = tcp_seek_last_pos(seq);
2091 if (rc)
2092 goto out;
2093 }
2094
2095 st->state = TCP_SEQ_STATE_LISTENING;
2096 st->num = 0;
2097 st->bucket = 0;
2098 st->offset = 0;
2099 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2100
2101out:
2102 st->last_pos = *pos;
2103 return rc;
2104}
2105
2106static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2107{
2108 struct tcp_iter_state *st = seq->private;
2109 void *rc = NULL;
2110
2111 if (v == SEQ_START_TOKEN) {
2112 rc = tcp_get_idx(seq, 0);
2113 goto out;
2114 }
2115
2116 switch (st->state) {
2117 case TCP_SEQ_STATE_LISTENING:
2118 rc = listening_get_next(seq, v);
2119 if (!rc) {
2120 st->state = TCP_SEQ_STATE_ESTABLISHED;
2121 st->bucket = 0;
2122 st->offset = 0;
2123 rc = established_get_first(seq);
2124 }
2125 break;
2126 case TCP_SEQ_STATE_ESTABLISHED:
2127 rc = established_get_next(seq, v);
2128 break;
2129 }
2130out:
2131 ++*pos;
2132 st->last_pos = *pos;
2133 return rc;
2134}
2135
2136static void tcp_seq_stop(struct seq_file *seq, void *v)
2137{
2138 struct tcp_iter_state *st = seq->private;
2139
2140 switch (st->state) {
2141 case TCP_SEQ_STATE_LISTENING:
2142 if (v != SEQ_START_TOKEN)
2143 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2144 break;
2145 case TCP_SEQ_STATE_ESTABLISHED:
2146 if (v)
2147 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2148 break;
2149 }
2150}
2151
2152int tcp_seq_open(struct inode *inode, struct file *file)
2153{
2154 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2155 struct tcp_iter_state *s;
2156 int err;
2157
2158 err = seq_open_net(inode, file, &afinfo->seq_ops,
2159 sizeof(struct tcp_iter_state));
2160 if (err < 0)
2161 return err;
2162
2163 s = ((struct seq_file *)file->private_data)->private;
2164 s->family = afinfo->family;
2165 s->last_pos = 0;
2166 return 0;
2167}
2168EXPORT_SYMBOL(tcp_seq_open);
2169
2170int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2171{
2172 int rc = 0;
2173 struct proc_dir_entry *p;
2174
2175 afinfo->seq_ops.start = tcp_seq_start;
2176 afinfo->seq_ops.next = tcp_seq_next;
2177 afinfo->seq_ops.stop = tcp_seq_stop;
2178
2179 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2180 afinfo->seq_fops, afinfo);
2181 if (!p)
2182 rc = -ENOMEM;
2183 return rc;
2184}
2185EXPORT_SYMBOL(tcp_proc_register);
2186
2187void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2188{
2189 remove_proc_entry(afinfo->name, net->proc_net);
2190}
2191EXPORT_SYMBOL(tcp_proc_unregister);
2192
2193static void get_openreq4(const struct request_sock *req,
2194 struct seq_file *f, int i)
2195{
2196 const struct inet_request_sock *ireq = inet_rsk(req);
2197 long delta = req->rsk_timer.expires - jiffies;
2198
2199 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2200 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2201 i,
2202 ireq->ir_loc_addr,
2203 ireq->ir_num,
2204 ireq->ir_rmt_addr,
2205 ntohs(ireq->ir_rmt_port),
2206 TCP_SYN_RECV,
2207 0, 0, /* could print option size, but that is af dependent. */
2208 1, /* timers active (only the expire timer) */
2209 jiffies_delta_to_clock_t(delta),
2210 req->num_timeout,
2211 from_kuid_munged(seq_user_ns(f),
2212 sock_i_uid(req->rsk_listener)),
2213 0, /* non standard timer */
2214 0, /* open_requests have no inode */
2215 0,
2216 req);
2217}
2218
2219static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2220{
2221 int timer_active;
2222 unsigned long timer_expires;
2223 const struct tcp_sock *tp = tcp_sk(sk);
2224 const struct inet_connection_sock *icsk = inet_csk(sk);
2225 const struct inet_sock *inet = inet_sk(sk);
2226 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2227 __be32 dest = inet->inet_daddr;
2228 __be32 src = inet->inet_rcv_saddr;
2229 __u16 destp = ntohs(inet->inet_dport);
2230 __u16 srcp = ntohs(inet->inet_sport);
2231 int rx_queue;
2232 int state;
2233
2234 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2235 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2236 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2237 timer_active = 1;
2238 timer_expires = icsk->icsk_timeout;
2239 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2240 timer_active = 4;
2241 timer_expires = icsk->icsk_timeout;
2242 } else if (timer_pending(&sk->sk_timer)) {
2243 timer_active = 2;
2244 timer_expires = sk->sk_timer.expires;
2245 } else {
2246 timer_active = 0;
2247 timer_expires = jiffies;
2248 }
2249
2250 state = sk_state_load(sk);
2251 if (state == TCP_LISTEN)
2252 rx_queue = sk->sk_ack_backlog;
2253 else
2254 /* Because we don't lock the socket,
2255 * we might find a transient negative value.
2256 */
2257 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2258
2259 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2260 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2261 i, src, srcp, dest, destp, state,
2262 tp->write_seq - tp->snd_una,
2263 rx_queue,
2264 timer_active,
2265 jiffies_delta_to_clock_t(timer_expires - jiffies),
2266 icsk->icsk_retransmits,
2267 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2268 icsk->icsk_probes_out,
2269 sock_i_ino(sk),
2270 atomic_read(&sk->sk_refcnt), sk,
2271 jiffies_to_clock_t(icsk->icsk_rto),
2272 jiffies_to_clock_t(icsk->icsk_ack.ato),
2273 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2274 tp->snd_cwnd,
2275 state == TCP_LISTEN ?
2276 fastopenq->max_qlen :
2277 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2278}
2279
2280static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2281 struct seq_file *f, int i)
2282{
2283 long delta = tw->tw_timer.expires - jiffies;
2284 __be32 dest, src;
2285 __u16 destp, srcp;
2286
2287 dest = tw->tw_daddr;
2288 src = tw->tw_rcv_saddr;
2289 destp = ntohs(tw->tw_dport);
2290 srcp = ntohs(tw->tw_sport);
2291
2292 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2293 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2294 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2295 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2296 atomic_read(&tw->tw_refcnt), tw);
2297}
2298
2299#define TMPSZ 150
2300
2301static int tcp4_seq_show(struct seq_file *seq, void *v)
2302{
2303 struct tcp_iter_state *st;
2304 struct sock *sk = v;
2305
2306 seq_setwidth(seq, TMPSZ - 1);
2307 if (v == SEQ_START_TOKEN) {
2308 seq_puts(seq, " sl local_address rem_address st tx_queue "
2309 "rx_queue tr tm->when retrnsmt uid timeout "
2310 "inode");
2311 goto out;
2312 }
2313 st = seq->private;
2314
2315 if (sk->sk_state == TCP_TIME_WAIT)
2316 get_timewait4_sock(v, seq, st->num);
2317 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2318 get_openreq4(v, seq, st->num);
2319 else
2320 get_tcp4_sock(v, seq, st->num);
2321out:
2322 seq_pad(seq, '\n');
2323 return 0;
2324}
2325
2326static const struct file_operations tcp_afinfo_seq_fops = {
2327 .owner = THIS_MODULE,
2328 .open = tcp_seq_open,
2329 .read = seq_read,
2330 .llseek = seq_lseek,
2331 .release = seq_release_net
2332};
2333
2334static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2335 .name = "tcp",
2336 .family = AF_INET,
2337 .seq_fops = &tcp_afinfo_seq_fops,
2338 .seq_ops = {
2339 .show = tcp4_seq_show,
2340 },
2341};
2342
2343static int __net_init tcp4_proc_init_net(struct net *net)
2344{
2345 return tcp_proc_register(net, &tcp4_seq_afinfo);
2346}
2347
2348static void __net_exit tcp4_proc_exit_net(struct net *net)
2349{
2350 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2351}
2352
2353static struct pernet_operations tcp4_net_ops = {
2354 .init = tcp4_proc_init_net,
2355 .exit = tcp4_proc_exit_net,
2356};
2357
2358int __init tcp4_proc_init(void)
2359{
2360 return register_pernet_subsys(&tcp4_net_ops);
2361}
2362
2363void tcp4_proc_exit(void)
2364{
2365 unregister_pernet_subsys(&tcp4_net_ops);
2366}
2367#endif /* CONFIG_PROC_FS */
2368
2369struct proto tcp_prot = {
2370 .name = "TCP",
2371 .owner = THIS_MODULE,
2372 .close = tcp_close,
2373 .connect = tcp_v4_connect,
2374 .disconnect = tcp_disconnect,
2375 .accept = inet_csk_accept,
2376 .ioctl = tcp_ioctl,
2377 .init = tcp_v4_init_sock,
2378 .destroy = tcp_v4_destroy_sock,
2379 .shutdown = tcp_shutdown,
2380 .setsockopt = tcp_setsockopt,
2381 .getsockopt = tcp_getsockopt,
2382 .recvmsg = tcp_recvmsg,
2383 .sendmsg = tcp_sendmsg,
2384 .sendpage = tcp_sendpage,
2385 .backlog_rcv = tcp_v4_do_rcv,
2386 .release_cb = tcp_release_cb,
2387 .hash = inet_hash,
2388 .unhash = inet_unhash,
2389 .get_port = inet_csk_get_port,
2390 .enter_memory_pressure = tcp_enter_memory_pressure,
2391 .stream_memory_free = tcp_stream_memory_free,
2392 .sockets_allocated = &tcp_sockets_allocated,
2393 .orphan_count = &tcp_orphan_count,
2394 .memory_allocated = &tcp_memory_allocated,
2395 .memory_pressure = &tcp_memory_pressure,
2396 .sysctl_mem = sysctl_tcp_mem,
2397 .sysctl_wmem = sysctl_tcp_wmem,
2398 .sysctl_rmem = sysctl_tcp_rmem,
2399 .max_header = MAX_TCP_HEADER,
2400 .obj_size = sizeof(struct tcp_sock),
2401 .slab_flags = SLAB_DESTROY_BY_RCU,
2402 .twsk_prot = &tcp_timewait_sock_ops,
2403 .rsk_prot = &tcp_request_sock_ops,
2404 .h.hashinfo = &tcp_hashinfo,
2405 .no_autobind = true,
2406#ifdef CONFIG_COMPAT
2407 .compat_setsockopt = compat_tcp_setsockopt,
2408 .compat_getsockopt = compat_tcp_getsockopt,
2409#endif
2410 .diag_destroy = tcp_abort,
2411};
2412EXPORT_SYMBOL(tcp_prot);
2413
2414static void __net_exit tcp_sk_exit(struct net *net)
2415{
2416 int cpu;
2417
2418 for_each_possible_cpu(cpu)
2419 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2420 free_percpu(net->ipv4.tcp_sk);
2421}
2422
2423static int __net_init tcp_sk_init(struct net *net)
2424{
2425 int res, cpu;
2426
2427 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2428 if (!net->ipv4.tcp_sk)
2429 return -ENOMEM;
2430
2431 for_each_possible_cpu(cpu) {
2432 struct sock *sk;
2433
2434 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2435 IPPROTO_TCP, net);
2436 if (res)
2437 goto fail;
2438 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2439 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2440 }
2441
2442 net->ipv4.sysctl_tcp_ecn = 2;
2443 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2444
2445 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2446 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2447 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2448
2449 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2450 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2451 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2452
2453 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2454 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2455 net->ipv4.sysctl_tcp_syncookies = 1;
2456 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2457 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2458 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2459 net->ipv4.sysctl_tcp_orphan_retries = 0;
2460 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2461 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2462 net->ipv4.sysctl_tcp_tw_reuse = 0;
2463
2464 return 0;
2465fail:
2466 tcp_sk_exit(net);
2467
2468 return res;
2469}
2470
2471static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2472{
2473 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2474}
2475
2476static struct pernet_operations __net_initdata tcp_sk_ops = {
2477 .init = tcp_sk_init,
2478 .exit = tcp_sk_exit,
2479 .exit_batch = tcp_sk_exit_batch,
2480};
2481
2482void __init tcp_v4_init(void)
2483{
2484 inet_hashinfo_init(&tcp_hashinfo);
2485 if (register_pernet_subsys(&tcp_sk_ops))
2486 panic("Failed to create the TCP control socket.\n");
2487}