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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/netdma.h>
76#include <net/secure_seq.h>
77#include <net/tcp_memcontrol.h>
78
79#include <linux/inet.h>
80#include <linux/ipv6.h>
81#include <linux/stddef.h>
82#include <linux/proc_fs.h>
83#include <linux/seq_file.h>
84
85#include <linux/crypto.h>
86#include <linux/scatterlist.h>
87
88int sysctl_tcp_tw_reuse __read_mostly;
89int sysctl_tcp_low_latency __read_mostly;
90EXPORT_SYMBOL(sysctl_tcp_low_latency);
91
92
93#ifdef CONFIG_TCP_MD5SIG
94static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, const struct tcphdr *th);
96#endif
97
98struct inet_hashinfo tcp_hashinfo;
99EXPORT_SYMBOL(tcp_hashinfo);
100
101static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
102{
103 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
104 ip_hdr(skb)->saddr,
105 tcp_hdr(skb)->dest,
106 tcp_hdr(skb)->source);
107}
108
109int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110{
111 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
112 struct tcp_sock *tp = tcp_sk(sk);
113
114 /* With PAWS, it is safe from the viewpoint
115 of data integrity. Even without PAWS it is safe provided sequence
116 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
117
118 Actually, the idea is close to VJ's one, only timestamp cache is
119 held not per host, but per port pair and TW bucket is used as state
120 holder.
121
122 If TW bucket has been already destroyed we fall back to VJ's scheme
123 and use initial timestamp retrieved from peer table.
124 */
125 if (tcptw->tw_ts_recent_stamp &&
126 (twp == NULL || (sysctl_tcp_tw_reuse &&
127 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
128 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
129 if (tp->write_seq == 0)
130 tp->write_seq = 1;
131 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
132 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
133 sock_hold(sktw);
134 return 1;
135 }
136
137 return 0;
138}
139EXPORT_SYMBOL_GPL(tcp_twsk_unique);
140
141static int tcp_repair_connect(struct sock *sk)
142{
143 tcp_connect_init(sk);
144 tcp_finish_connect(sk, NULL);
145
146 return 0;
147}
148
149/* This will initiate an outgoing connection. */
150int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
151{
152 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
153 struct inet_sock *inet = inet_sk(sk);
154 struct tcp_sock *tp = tcp_sk(sk);
155 __be16 orig_sport, orig_dport;
156 __be32 daddr, nexthop;
157 struct flowi4 *fl4;
158 struct rtable *rt;
159 int err;
160 struct ip_options_rcu *inet_opt;
161
162 if (addr_len < sizeof(struct sockaddr_in))
163 return -EINVAL;
164
165 if (usin->sin_family != AF_INET)
166 return -EAFNOSUPPORT;
167
168 nexthop = daddr = usin->sin_addr.s_addr;
169 inet_opt = rcu_dereference_protected(inet->inet_opt,
170 sock_owned_by_user(sk));
171 if (inet_opt && inet_opt->opt.srr) {
172 if (!daddr)
173 return -EINVAL;
174 nexthop = inet_opt->opt.faddr;
175 }
176
177 orig_sport = inet->inet_sport;
178 orig_dport = usin->sin_port;
179 fl4 = &inet->cork.fl.u.ip4;
180 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
181 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
182 IPPROTO_TCP,
183 orig_sport, orig_dport, sk, true);
184 if (IS_ERR(rt)) {
185 err = PTR_ERR(rt);
186 if (err == -ENETUNREACH)
187 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
188 return err;
189 }
190
191 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
192 ip_rt_put(rt);
193 return -ENETUNREACH;
194 }
195
196 if (!inet_opt || !inet_opt->opt.srr)
197 daddr = fl4->daddr;
198
199 if (!inet->inet_saddr)
200 inet->inet_saddr = fl4->saddr;
201 inet->inet_rcv_saddr = inet->inet_saddr;
202
203 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
204 /* Reset inherited state */
205 tp->rx_opt.ts_recent = 0;
206 tp->rx_opt.ts_recent_stamp = 0;
207 if (likely(!tp->repair))
208 tp->write_seq = 0;
209 }
210
211 if (tcp_death_row.sysctl_tw_recycle &&
212 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
213 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
214 /*
215 * VJ's idea. We save last timestamp seen from
216 * the destination in peer table, when entering state
217 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
218 * when trying new connection.
219 */
220 if (peer) {
221 inet_peer_refcheck(peer);
222 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
223 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
224 tp->rx_opt.ts_recent = peer->tcp_ts;
225 }
226 }
227 }
228
229 inet->inet_dport = usin->sin_port;
230 inet->inet_daddr = daddr;
231
232 inet_csk(sk)->icsk_ext_hdr_len = 0;
233 if (inet_opt)
234 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
235
236 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
237
238 /* Socket identity is still unknown (sport may be zero).
239 * However we set state to SYN-SENT and not releasing socket
240 * lock select source port, enter ourselves into the hash tables and
241 * complete initialization after this.
242 */
243 tcp_set_state(sk, TCP_SYN_SENT);
244 err = inet_hash_connect(&tcp_death_row, sk);
245 if (err)
246 goto failure;
247
248 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
249 inet->inet_sport, inet->inet_dport, sk);
250 if (IS_ERR(rt)) {
251 err = PTR_ERR(rt);
252 rt = NULL;
253 goto failure;
254 }
255 /* OK, now commit destination to socket. */
256 sk->sk_gso_type = SKB_GSO_TCPV4;
257 sk_setup_caps(sk, &rt->dst);
258
259 if (!tp->write_seq && likely(!tp->repair))
260 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
261 inet->inet_daddr,
262 inet->inet_sport,
263 usin->sin_port);
264
265 inet->inet_id = tp->write_seq ^ jiffies;
266
267 if (likely(!tp->repair))
268 err = tcp_connect(sk);
269 else
270 err = tcp_repair_connect(sk);
271
272 rt = NULL;
273 if (err)
274 goto failure;
275
276 return 0;
277
278failure:
279 /*
280 * This unhashes the socket and releases the local port,
281 * if necessary.
282 */
283 tcp_set_state(sk, TCP_CLOSE);
284 ip_rt_put(rt);
285 sk->sk_route_caps = 0;
286 inet->inet_dport = 0;
287 return err;
288}
289EXPORT_SYMBOL(tcp_v4_connect);
290
291/*
292 * This routine does path mtu discovery as defined in RFC1191.
293 */
294static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
295{
296 struct dst_entry *dst;
297 struct inet_sock *inet = inet_sk(sk);
298
299 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
300 * send out by Linux are always <576bytes so they should go through
301 * unfragmented).
302 */
303 if (sk->sk_state == TCP_LISTEN)
304 return;
305
306 /* We don't check in the destentry if pmtu discovery is forbidden
307 * on this route. We just assume that no packet_to_big packets
308 * are send back when pmtu discovery is not active.
309 * There is a small race when the user changes this flag in the
310 * route, but I think that's acceptable.
311 */
312 if ((dst = __sk_dst_check(sk, 0)) == NULL)
313 return;
314
315 dst->ops->update_pmtu(dst, mtu);
316
317 /* Something is about to be wrong... Remember soft error
318 * for the case, if this connection will not able to recover.
319 */
320 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
321 sk->sk_err_soft = EMSGSIZE;
322
323 mtu = dst_mtu(dst);
324
325 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
326 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
327 tcp_sync_mss(sk, mtu);
328
329 /* Resend the TCP packet because it's
330 * clear that the old packet has been
331 * dropped. This is the new "fast" path mtu
332 * discovery.
333 */
334 tcp_simple_retransmit(sk);
335 } /* else let the usual retransmit timer handle it */
336}
337
338/*
339 * This routine is called by the ICMP module when it gets some
340 * sort of error condition. If err < 0 then the socket should
341 * be closed and the error returned to the user. If err > 0
342 * it's just the icmp type << 8 | icmp code. After adjustment
343 * header points to the first 8 bytes of the tcp header. We need
344 * to find the appropriate port.
345 *
346 * The locking strategy used here is very "optimistic". When
347 * someone else accesses the socket the ICMP is just dropped
348 * and for some paths there is no check at all.
349 * A more general error queue to queue errors for later handling
350 * is probably better.
351 *
352 */
353
354void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
355{
356 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
357 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
358 struct inet_connection_sock *icsk;
359 struct tcp_sock *tp;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(icmp_skb)->type;
362 const int code = icmp_hdr(icmp_skb)->code;
363 struct sock *sk;
364 struct sk_buff *skb;
365 __u32 seq;
366 __u32 remaining;
367 int err;
368 struct net *net = dev_net(icmp_skb->dev);
369
370 if (icmp_skb->len < (iph->ihl << 2) + 8) {
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
372 return;
373 }
374
375 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
376 iph->saddr, th->source, inet_iif(icmp_skb));
377 if (!sk) {
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
379 return;
380 }
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
383 return;
384 }
385
386 bh_lock_sock(sk);
387 /* If too many ICMPs get dropped on busy
388 * servers this needs to be solved differently.
389 */
390 if (sock_owned_by_user(sk))
391 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
392
393 if (sk->sk_state == TCP_CLOSE)
394 goto out;
395
396 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
397 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
398 goto out;
399 }
400
401 icsk = inet_csk(sk);
402 tp = tcp_sk(sk);
403 seq = ntohl(th->seq);
404 if (sk->sk_state != TCP_LISTEN &&
405 !between(seq, tp->snd_una, tp->snd_nxt)) {
406 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
407 goto out;
408 }
409
410 switch (type) {
411 case ICMP_SOURCE_QUENCH:
412 /* Just silently ignore these. */
413 goto out;
414 case ICMP_PARAMETERPROB:
415 err = EPROTO;
416 break;
417 case ICMP_DEST_UNREACH:
418 if (code > NR_ICMP_UNREACH)
419 goto out;
420
421 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
422 if (!sock_owned_by_user(sk))
423 do_pmtu_discovery(sk, iph, info);
424 goto out;
425 }
426
427 err = icmp_err_convert[code].errno;
428 /* check if icmp_skb allows revert of backoff
429 * (see draft-zimmermann-tcp-lcd) */
430 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
431 break;
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
433 !icsk->icsk_backoff)
434 break;
435
436 if (sock_owned_by_user(sk))
437 break;
438
439 icsk->icsk_backoff--;
440 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
441 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
442 tcp_bound_rto(sk);
443
444 skb = tcp_write_queue_head(sk);
445 BUG_ON(!skb);
446
447 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
448 tcp_time_stamp - TCP_SKB_CB(skb)->when);
449
450 if (remaining) {
451 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
452 remaining, TCP_RTO_MAX);
453 } else {
454 /* RTO revert clocked out retransmission.
455 * Will retransmit now */
456 tcp_retransmit_timer(sk);
457 }
458
459 break;
460 case ICMP_TIME_EXCEEDED:
461 err = EHOSTUNREACH;
462 break;
463 default:
464 goto out;
465 }
466
467 switch (sk->sk_state) {
468 struct request_sock *req, **prev;
469 case TCP_LISTEN:
470 if (sock_owned_by_user(sk))
471 goto out;
472
473 req = inet_csk_search_req(sk, &prev, th->dest,
474 iph->daddr, iph->saddr);
475 if (!req)
476 goto out;
477
478 /* ICMPs are not backlogged, hence we cannot get
479 an established socket here.
480 */
481 WARN_ON(req->sk);
482
483 if (seq != tcp_rsk(req)->snt_isn) {
484 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
485 goto out;
486 }
487
488 /*
489 * Still in SYN_RECV, just remove it silently.
490 * There is no good way to pass the error to the newly
491 * created socket, and POSIX does not want network
492 * errors returned from accept().
493 */
494 inet_csk_reqsk_queue_drop(sk, req, prev);
495 goto out;
496
497 case TCP_SYN_SENT:
498 case TCP_SYN_RECV: /* Cannot happen.
499 It can f.e. if SYNs crossed.
500 */
501 if (!sock_owned_by_user(sk)) {
502 sk->sk_err = err;
503
504 sk->sk_error_report(sk);
505
506 tcp_done(sk);
507 } else {
508 sk->sk_err_soft = err;
509 }
510 goto out;
511 }
512
513 /* If we've already connected we will keep trying
514 * until we time out, or the user gives up.
515 *
516 * rfc1122 4.2.3.9 allows to consider as hard errors
517 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
518 * but it is obsoleted by pmtu discovery).
519 *
520 * Note, that in modern internet, where routing is unreliable
521 * and in each dark corner broken firewalls sit, sending random
522 * errors ordered by their masters even this two messages finally lose
523 * their original sense (even Linux sends invalid PORT_UNREACHs)
524 *
525 * Now we are in compliance with RFCs.
526 * --ANK (980905)
527 */
528
529 inet = inet_sk(sk);
530 if (!sock_owned_by_user(sk) && inet->recverr) {
531 sk->sk_err = err;
532 sk->sk_error_report(sk);
533 } else { /* Only an error on timeout */
534 sk->sk_err_soft = err;
535 }
536
537out:
538 bh_unlock_sock(sk);
539 sock_put(sk);
540}
541
542static void __tcp_v4_send_check(struct sk_buff *skb,
543 __be32 saddr, __be32 daddr)
544{
545 struct tcphdr *th = tcp_hdr(skb);
546
547 if (skb->ip_summed == CHECKSUM_PARTIAL) {
548 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
549 skb->csum_start = skb_transport_header(skb) - skb->head;
550 skb->csum_offset = offsetof(struct tcphdr, check);
551 } else {
552 th->check = tcp_v4_check(skb->len, saddr, daddr,
553 csum_partial(th,
554 th->doff << 2,
555 skb->csum));
556 }
557}
558
559/* This routine computes an IPv4 TCP checksum. */
560void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
561{
562 const struct inet_sock *inet = inet_sk(sk);
563
564 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
565}
566EXPORT_SYMBOL(tcp_v4_send_check);
567
568int tcp_v4_gso_send_check(struct sk_buff *skb)
569{
570 const struct iphdr *iph;
571 struct tcphdr *th;
572
573 if (!pskb_may_pull(skb, sizeof(*th)))
574 return -EINVAL;
575
576 iph = ip_hdr(skb);
577 th = tcp_hdr(skb);
578
579 th->check = 0;
580 skb->ip_summed = CHECKSUM_PARTIAL;
581 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
582 return 0;
583}
584
585/*
586 * This routine will send an RST to the other tcp.
587 *
588 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
589 * for reset.
590 * Answer: if a packet caused RST, it is not for a socket
591 * existing in our system, if it is matched to a socket,
592 * it is just duplicate segment or bug in other side's TCP.
593 * So that we build reply only basing on parameters
594 * arrived with segment.
595 * Exception: precedence violation. We do not implement it in any case.
596 */
597
598static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
599{
600 const struct tcphdr *th = tcp_hdr(skb);
601 struct {
602 struct tcphdr th;
603#ifdef CONFIG_TCP_MD5SIG
604 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
605#endif
606 } rep;
607 struct ip_reply_arg arg;
608#ifdef CONFIG_TCP_MD5SIG
609 struct tcp_md5sig_key *key;
610 const __u8 *hash_location = NULL;
611 unsigned char newhash[16];
612 int genhash;
613 struct sock *sk1 = NULL;
614#endif
615 struct net *net;
616
617 /* Never send a reset in response to a reset. */
618 if (th->rst)
619 return;
620
621 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
622 return;
623
624 /* Swap the send and the receive. */
625 memset(&rep, 0, sizeof(rep));
626 rep.th.dest = th->source;
627 rep.th.source = th->dest;
628 rep.th.doff = sizeof(struct tcphdr) / 4;
629 rep.th.rst = 1;
630
631 if (th->ack) {
632 rep.th.seq = th->ack_seq;
633 } else {
634 rep.th.ack = 1;
635 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
636 skb->len - (th->doff << 2));
637 }
638
639 memset(&arg, 0, sizeof(arg));
640 arg.iov[0].iov_base = (unsigned char *)&rep;
641 arg.iov[0].iov_len = sizeof(rep.th);
642
643#ifdef CONFIG_TCP_MD5SIG
644 hash_location = tcp_parse_md5sig_option(th);
645 if (!sk && hash_location) {
646 /*
647 * active side is lost. Try to find listening socket through
648 * source port, and then find md5 key through listening socket.
649 * we are not loose security here:
650 * Incoming packet is checked with md5 hash with finding key,
651 * no RST generated if md5 hash doesn't match.
652 */
653 sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev),
654 &tcp_hashinfo, ip_hdr(skb)->daddr,
655 ntohs(th->source), inet_iif(skb));
656 /* don't send rst if it can't find key */
657 if (!sk1)
658 return;
659 rcu_read_lock();
660 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
661 &ip_hdr(skb)->saddr, AF_INET);
662 if (!key)
663 goto release_sk1;
664
665 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
666 if (genhash || memcmp(hash_location, newhash, 16) != 0)
667 goto release_sk1;
668 } else {
669 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
670 &ip_hdr(skb)->saddr,
671 AF_INET) : NULL;
672 }
673
674 if (key) {
675 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
676 (TCPOPT_NOP << 16) |
677 (TCPOPT_MD5SIG << 8) |
678 TCPOLEN_MD5SIG);
679 /* Update length and the length the header thinks exists */
680 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
681 rep.th.doff = arg.iov[0].iov_len / 4;
682
683 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
684 key, ip_hdr(skb)->saddr,
685 ip_hdr(skb)->daddr, &rep.th);
686 }
687#endif
688 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
689 ip_hdr(skb)->saddr, /* XXX */
690 arg.iov[0].iov_len, IPPROTO_TCP, 0);
691 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
692 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
693 /* When socket is gone, all binding information is lost.
694 * routing might fail in this case. using iif for oif to
695 * make sure we can deliver it
696 */
697 arg.bound_dev_if = sk ? sk->sk_bound_dev_if : inet_iif(skb);
698
699 net = dev_net(skb_dst(skb)->dev);
700 arg.tos = ip_hdr(skb)->tos;
701 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
702 &arg, arg.iov[0].iov_len);
703
704 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
705 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
706
707#ifdef CONFIG_TCP_MD5SIG
708release_sk1:
709 if (sk1) {
710 rcu_read_unlock();
711 sock_put(sk1);
712 }
713#endif
714}
715
716/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
717 outside socket context is ugly, certainly. What can I do?
718 */
719
720static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
721 u32 win, u32 ts, 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 ip_reply_arg arg;
735 struct net *net = dev_net(skb_dst(skb)->dev);
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 (ts) {
743 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
744 (TCPOPT_TIMESTAMP << 8) |
745 TCPOLEN_TIMESTAMP);
746 rep.opt[1] = htonl(tcp_time_stamp);
747 rep.opt[2] = htonl(ts);
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 = (ts) ? 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 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
785 &arg, arg.iov[0].iov_len);
786
787 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
788}
789
790static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
791{
792 struct inet_timewait_sock *tw = inet_twsk(sk);
793 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
794
795 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
796 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
797 tcptw->tw_ts_recent,
798 tw->tw_bound_dev_if,
799 tcp_twsk_md5_key(tcptw),
800 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
801 tw->tw_tos
802 );
803
804 inet_twsk_put(tw);
805}
806
807static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
808 struct request_sock *req)
809{
810 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
811 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
812 req->ts_recent,
813 0,
814 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
815 AF_INET),
816 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
817 ip_hdr(skb)->tos);
818}
819
820/*
821 * Send a SYN-ACK after having received a SYN.
822 * This still operates on a request_sock only, not on a big
823 * socket.
824 */
825static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
826 struct request_sock *req,
827 struct request_values *rvp,
828 u16 queue_mapping)
829{
830 const struct inet_request_sock *ireq = inet_rsk(req);
831 struct flowi4 fl4;
832 int err = -1;
833 struct sk_buff * skb;
834
835 /* First, grab a route. */
836 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
837 return -1;
838
839 skb = tcp_make_synack(sk, dst, req, rvp);
840
841 if (skb) {
842 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
843
844 skb_set_queue_mapping(skb, queue_mapping);
845 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
846 ireq->rmt_addr,
847 ireq->opt);
848 err = net_xmit_eval(err);
849 }
850
851 dst_release(dst);
852 return err;
853}
854
855static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
856 struct request_values *rvp)
857{
858 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
859 return tcp_v4_send_synack(sk, NULL, req, rvp, 0);
860}
861
862/*
863 * IPv4 request_sock destructor.
864 */
865static void tcp_v4_reqsk_destructor(struct request_sock *req)
866{
867 kfree(inet_rsk(req)->opt);
868}
869
870/*
871 * Return true if a syncookie should be sent
872 */
873bool tcp_syn_flood_action(struct sock *sk,
874 const struct sk_buff *skb,
875 const char *proto)
876{
877 const char *msg = "Dropping request";
878 bool want_cookie = false;
879 struct listen_sock *lopt;
880
881
882
883#ifdef CONFIG_SYN_COOKIES
884 if (sysctl_tcp_syncookies) {
885 msg = "Sending cookies";
886 want_cookie = true;
887 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
888 } else
889#endif
890 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
891
892 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
893 if (!lopt->synflood_warned) {
894 lopt->synflood_warned = 1;
895 pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
896 proto, ntohs(tcp_hdr(skb)->dest), msg);
897 }
898 return want_cookie;
899}
900EXPORT_SYMBOL(tcp_syn_flood_action);
901
902/*
903 * Save and compile IPv4 options into the request_sock if needed.
904 */
905static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
906 struct sk_buff *skb)
907{
908 const struct ip_options *opt = &(IPCB(skb)->opt);
909 struct ip_options_rcu *dopt = NULL;
910
911 if (opt && opt->optlen) {
912 int opt_size = sizeof(*dopt) + opt->optlen;
913
914 dopt = kmalloc(opt_size, GFP_ATOMIC);
915 if (dopt) {
916 if (ip_options_echo(&dopt->opt, skb)) {
917 kfree(dopt);
918 dopt = NULL;
919 }
920 }
921 }
922 return dopt;
923}
924
925#ifdef CONFIG_TCP_MD5SIG
926/*
927 * RFC2385 MD5 checksumming requires a mapping of
928 * IP address->MD5 Key.
929 * We need to maintain these in the sk structure.
930 */
931
932/* Find the Key structure for an address. */
933struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
934 const union tcp_md5_addr *addr,
935 int family)
936{
937 struct tcp_sock *tp = tcp_sk(sk);
938 struct tcp_md5sig_key *key;
939 struct hlist_node *pos;
940 unsigned int size = sizeof(struct in_addr);
941 struct tcp_md5sig_info *md5sig;
942
943 /* caller either holds rcu_read_lock() or socket lock */
944 md5sig = rcu_dereference_check(tp->md5sig_info,
945 sock_owned_by_user(sk) ||
946 lockdep_is_held(&sk->sk_lock.slock));
947 if (!md5sig)
948 return NULL;
949#if IS_ENABLED(CONFIG_IPV6)
950 if (family == AF_INET6)
951 size = sizeof(struct in6_addr);
952#endif
953 hlist_for_each_entry_rcu(key, pos, &md5sig->head, node) {
954 if (key->family != family)
955 continue;
956 if (!memcmp(&key->addr, addr, size))
957 return key;
958 }
959 return NULL;
960}
961EXPORT_SYMBOL(tcp_md5_do_lookup);
962
963struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
964 struct sock *addr_sk)
965{
966 union tcp_md5_addr *addr;
967
968 addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
969 return tcp_md5_do_lookup(sk, addr, AF_INET);
970}
971EXPORT_SYMBOL(tcp_v4_md5_lookup);
972
973static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
974 struct request_sock *req)
975{
976 union tcp_md5_addr *addr;
977
978 addr = (union tcp_md5_addr *)&inet_rsk(req)->rmt_addr;
979 return tcp_md5_do_lookup(sk, addr, AF_INET);
980}
981
982/* This can be called on a newly created socket, from other files */
983int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
984 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
985{
986 /* Add Key to the list */
987 struct tcp_md5sig_key *key;
988 struct tcp_sock *tp = tcp_sk(sk);
989 struct tcp_md5sig_info *md5sig;
990
991 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
992 if (key) {
993 /* Pre-existing entry - just update that one. */
994 memcpy(key->key, newkey, newkeylen);
995 key->keylen = newkeylen;
996 return 0;
997 }
998
999 md5sig = rcu_dereference_protected(tp->md5sig_info,
1000 sock_owned_by_user(sk));
1001 if (!md5sig) {
1002 md5sig = kmalloc(sizeof(*md5sig), gfp);
1003 if (!md5sig)
1004 return -ENOMEM;
1005
1006 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1007 INIT_HLIST_HEAD(&md5sig->head);
1008 rcu_assign_pointer(tp->md5sig_info, md5sig);
1009 }
1010
1011 key = sock_kmalloc(sk, sizeof(*key), gfp);
1012 if (!key)
1013 return -ENOMEM;
1014 if (hlist_empty(&md5sig->head) && !tcp_alloc_md5sig_pool(sk)) {
1015 sock_kfree_s(sk, key, sizeof(*key));
1016 return -ENOMEM;
1017 }
1018
1019 memcpy(key->key, newkey, newkeylen);
1020 key->keylen = newkeylen;
1021 key->family = family;
1022 memcpy(&key->addr, addr,
1023 (family == AF_INET6) ? sizeof(struct in6_addr) :
1024 sizeof(struct in_addr));
1025 hlist_add_head_rcu(&key->node, &md5sig->head);
1026 return 0;
1027}
1028EXPORT_SYMBOL(tcp_md5_do_add);
1029
1030int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
1031{
1032 struct tcp_sock *tp = tcp_sk(sk);
1033 struct tcp_md5sig_key *key;
1034 struct tcp_md5sig_info *md5sig;
1035
1036 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
1037 if (!key)
1038 return -ENOENT;
1039 hlist_del_rcu(&key->node);
1040 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1041 kfree_rcu(key, rcu);
1042 md5sig = rcu_dereference_protected(tp->md5sig_info,
1043 sock_owned_by_user(sk));
1044 if (hlist_empty(&md5sig->head))
1045 tcp_free_md5sig_pool();
1046 return 0;
1047}
1048EXPORT_SYMBOL(tcp_md5_do_del);
1049
1050void tcp_clear_md5_list(struct sock *sk)
1051{
1052 struct tcp_sock *tp = tcp_sk(sk);
1053 struct tcp_md5sig_key *key;
1054 struct hlist_node *pos, *n;
1055 struct tcp_md5sig_info *md5sig;
1056
1057 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1058
1059 if (!hlist_empty(&md5sig->head))
1060 tcp_free_md5sig_pool();
1061 hlist_for_each_entry_safe(key, pos, n, &md5sig->head, node) {
1062 hlist_del_rcu(&key->node);
1063 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1064 kfree_rcu(key, rcu);
1065 }
1066}
1067
1068static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1069 int optlen)
1070{
1071 struct tcp_md5sig cmd;
1072 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1073
1074 if (optlen < sizeof(cmd))
1075 return -EINVAL;
1076
1077 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1078 return -EFAULT;
1079
1080 if (sin->sin_family != AF_INET)
1081 return -EINVAL;
1082
1083 if (!cmd.tcpm_key || !cmd.tcpm_keylen)
1084 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1085 AF_INET);
1086
1087 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1088 return -EINVAL;
1089
1090 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1091 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1092 GFP_KERNEL);
1093}
1094
1095static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1096 __be32 daddr, __be32 saddr, int nbytes)
1097{
1098 struct tcp4_pseudohdr *bp;
1099 struct scatterlist sg;
1100
1101 bp = &hp->md5_blk.ip4;
1102
1103 /*
1104 * 1. the TCP pseudo-header (in the order: source IP address,
1105 * destination IP address, zero-padded protocol number, and
1106 * segment length)
1107 */
1108 bp->saddr = saddr;
1109 bp->daddr = daddr;
1110 bp->pad = 0;
1111 bp->protocol = IPPROTO_TCP;
1112 bp->len = cpu_to_be16(nbytes);
1113
1114 sg_init_one(&sg, bp, sizeof(*bp));
1115 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1116}
1117
1118static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1119 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1120{
1121 struct tcp_md5sig_pool *hp;
1122 struct hash_desc *desc;
1123
1124 hp = tcp_get_md5sig_pool();
1125 if (!hp)
1126 goto clear_hash_noput;
1127 desc = &hp->md5_desc;
1128
1129 if (crypto_hash_init(desc))
1130 goto clear_hash;
1131 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1132 goto clear_hash;
1133 if (tcp_md5_hash_header(hp, th))
1134 goto clear_hash;
1135 if (tcp_md5_hash_key(hp, key))
1136 goto clear_hash;
1137 if (crypto_hash_final(desc, md5_hash))
1138 goto clear_hash;
1139
1140 tcp_put_md5sig_pool();
1141 return 0;
1142
1143clear_hash:
1144 tcp_put_md5sig_pool();
1145clear_hash_noput:
1146 memset(md5_hash, 0, 16);
1147 return 1;
1148}
1149
1150int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1151 const struct sock *sk, const struct request_sock *req,
1152 const struct sk_buff *skb)
1153{
1154 struct tcp_md5sig_pool *hp;
1155 struct hash_desc *desc;
1156 const struct tcphdr *th = tcp_hdr(skb);
1157 __be32 saddr, daddr;
1158
1159 if (sk) {
1160 saddr = inet_sk(sk)->inet_saddr;
1161 daddr = inet_sk(sk)->inet_daddr;
1162 } else if (req) {
1163 saddr = inet_rsk(req)->loc_addr;
1164 daddr = inet_rsk(req)->rmt_addr;
1165 } else {
1166 const struct iphdr *iph = ip_hdr(skb);
1167 saddr = iph->saddr;
1168 daddr = iph->daddr;
1169 }
1170
1171 hp = tcp_get_md5sig_pool();
1172 if (!hp)
1173 goto clear_hash_noput;
1174 desc = &hp->md5_desc;
1175
1176 if (crypto_hash_init(desc))
1177 goto clear_hash;
1178
1179 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1180 goto clear_hash;
1181 if (tcp_md5_hash_header(hp, th))
1182 goto clear_hash;
1183 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1184 goto clear_hash;
1185 if (tcp_md5_hash_key(hp, key))
1186 goto clear_hash;
1187 if (crypto_hash_final(desc, md5_hash))
1188 goto clear_hash;
1189
1190 tcp_put_md5sig_pool();
1191 return 0;
1192
1193clear_hash:
1194 tcp_put_md5sig_pool();
1195clear_hash_noput:
1196 memset(md5_hash, 0, 16);
1197 return 1;
1198}
1199EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1200
1201static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1202{
1203 /*
1204 * This gets called for each TCP segment that arrives
1205 * so we want to be efficient.
1206 * We have 3 drop cases:
1207 * o No MD5 hash and one expected.
1208 * o MD5 hash and we're not expecting one.
1209 * o MD5 hash and its wrong.
1210 */
1211 const __u8 *hash_location = NULL;
1212 struct tcp_md5sig_key *hash_expected;
1213 const struct iphdr *iph = ip_hdr(skb);
1214 const struct tcphdr *th = tcp_hdr(skb);
1215 int genhash;
1216 unsigned char newhash[16];
1217
1218 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1219 AF_INET);
1220 hash_location = tcp_parse_md5sig_option(th);
1221
1222 /* We've parsed the options - do we have a hash? */
1223 if (!hash_expected && !hash_location)
1224 return false;
1225
1226 if (hash_expected && !hash_location) {
1227 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1228 return true;
1229 }
1230
1231 if (!hash_expected && hash_location) {
1232 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1233 return true;
1234 }
1235
1236 /* Okay, so this is hash_expected and hash_location -
1237 * so we need to calculate the checksum.
1238 */
1239 genhash = tcp_v4_md5_hash_skb(newhash,
1240 hash_expected,
1241 NULL, NULL, skb);
1242
1243 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1244 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1245 &iph->saddr, ntohs(th->source),
1246 &iph->daddr, ntohs(th->dest),
1247 genhash ? " tcp_v4_calc_md5_hash failed"
1248 : "");
1249 return true;
1250 }
1251 return false;
1252}
1253
1254#endif
1255
1256struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1257 .family = PF_INET,
1258 .obj_size = sizeof(struct tcp_request_sock),
1259 .rtx_syn_ack = tcp_v4_rtx_synack,
1260 .send_ack = tcp_v4_reqsk_send_ack,
1261 .destructor = tcp_v4_reqsk_destructor,
1262 .send_reset = tcp_v4_send_reset,
1263 .syn_ack_timeout = tcp_syn_ack_timeout,
1264};
1265
1266#ifdef CONFIG_TCP_MD5SIG
1267static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1268 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1269 .calc_md5_hash = tcp_v4_md5_hash_skb,
1270};
1271#endif
1272
1273int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1274{
1275 struct tcp_extend_values tmp_ext;
1276 struct tcp_options_received tmp_opt;
1277 const u8 *hash_location;
1278 struct request_sock *req;
1279 struct inet_request_sock *ireq;
1280 struct tcp_sock *tp = tcp_sk(sk);
1281 struct dst_entry *dst = NULL;
1282 __be32 saddr = ip_hdr(skb)->saddr;
1283 __be32 daddr = ip_hdr(skb)->daddr;
1284 __u32 isn = TCP_SKB_CB(skb)->when;
1285 bool want_cookie = false;
1286
1287 /* Never answer to SYNs send to broadcast or multicast */
1288 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1289 goto drop;
1290
1291 /* TW buckets are converted to open requests without
1292 * limitations, they conserve resources and peer is
1293 * evidently real one.
1294 */
1295 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1296 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1297 if (!want_cookie)
1298 goto drop;
1299 }
1300
1301 /* Accept backlog is full. If we have already queued enough
1302 * of warm entries in syn queue, drop request. It is better than
1303 * clogging syn queue with openreqs with exponentially increasing
1304 * timeout.
1305 */
1306 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1307 goto drop;
1308
1309 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1310 if (!req)
1311 goto drop;
1312
1313#ifdef CONFIG_TCP_MD5SIG
1314 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1315#endif
1316
1317 tcp_clear_options(&tmp_opt);
1318 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1319 tmp_opt.user_mss = tp->rx_opt.user_mss;
1320 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1321
1322 if (tmp_opt.cookie_plus > 0 &&
1323 tmp_opt.saw_tstamp &&
1324 !tp->rx_opt.cookie_out_never &&
1325 (sysctl_tcp_cookie_size > 0 ||
1326 (tp->cookie_values != NULL &&
1327 tp->cookie_values->cookie_desired > 0))) {
1328 u8 *c;
1329 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1330 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1331
1332 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1333 goto drop_and_release;
1334
1335 /* Secret recipe starts with IP addresses */
1336 *mess++ ^= (__force u32)daddr;
1337 *mess++ ^= (__force u32)saddr;
1338
1339 /* plus variable length Initiator Cookie */
1340 c = (u8 *)mess;
1341 while (l-- > 0)
1342 *c++ ^= *hash_location++;
1343
1344 want_cookie = false; /* not our kind of cookie */
1345 tmp_ext.cookie_out_never = 0; /* false */
1346 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1347 } else if (!tp->rx_opt.cookie_in_always) {
1348 /* redundant indications, but ensure initialization. */
1349 tmp_ext.cookie_out_never = 1; /* true */
1350 tmp_ext.cookie_plus = 0;
1351 } else {
1352 goto drop_and_release;
1353 }
1354 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1355
1356 if (want_cookie && !tmp_opt.saw_tstamp)
1357 tcp_clear_options(&tmp_opt);
1358
1359 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1360 tcp_openreq_init(req, &tmp_opt, skb);
1361
1362 ireq = inet_rsk(req);
1363 ireq->loc_addr = daddr;
1364 ireq->rmt_addr = saddr;
1365 ireq->no_srccheck = inet_sk(sk)->transparent;
1366 ireq->opt = tcp_v4_save_options(sk, skb);
1367
1368 if (security_inet_conn_request(sk, skb, req))
1369 goto drop_and_free;
1370
1371 if (!want_cookie || tmp_opt.tstamp_ok)
1372 TCP_ECN_create_request(req, skb);
1373
1374 if (want_cookie) {
1375 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1376 req->cookie_ts = tmp_opt.tstamp_ok;
1377 } else if (!isn) {
1378 struct inet_peer *peer = NULL;
1379 struct flowi4 fl4;
1380
1381 /* VJ's idea. We save last timestamp seen
1382 * from the destination in peer table, when entering
1383 * state TIME-WAIT, and check against it before
1384 * accepting new connection request.
1385 *
1386 * If "isn" is not zero, this request hit alive
1387 * timewait bucket, so that all the necessary checks
1388 * are made in the function processing timewait state.
1389 */
1390 if (tmp_opt.saw_tstamp &&
1391 tcp_death_row.sysctl_tw_recycle &&
1392 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1393 fl4.daddr == saddr &&
1394 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1395 inet_peer_refcheck(peer);
1396 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1397 (s32)(peer->tcp_ts - req->ts_recent) >
1398 TCP_PAWS_WINDOW) {
1399 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1400 goto drop_and_release;
1401 }
1402 }
1403 /* Kill the following clause, if you dislike this way. */
1404 else if (!sysctl_tcp_syncookies &&
1405 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1406 (sysctl_max_syn_backlog >> 2)) &&
1407 (!peer || !peer->tcp_ts_stamp) &&
1408 (!dst || !dst_metric(dst, RTAX_RTT))) {
1409 /* Without syncookies last quarter of
1410 * backlog is filled with destinations,
1411 * proven to be alive.
1412 * It means that we continue to communicate
1413 * to destinations, already remembered
1414 * to the moment of synflood.
1415 */
1416 LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"),
1417 &saddr, ntohs(tcp_hdr(skb)->source));
1418 goto drop_and_release;
1419 }
1420
1421 isn = tcp_v4_init_sequence(skb);
1422 }
1423 tcp_rsk(req)->snt_isn = isn;
1424 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1425
1426 if (tcp_v4_send_synack(sk, dst, req,
1427 (struct request_values *)&tmp_ext,
1428 skb_get_queue_mapping(skb)) ||
1429 want_cookie)
1430 goto drop_and_free;
1431
1432 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1433 return 0;
1434
1435drop_and_release:
1436 dst_release(dst);
1437drop_and_free:
1438 reqsk_free(req);
1439drop:
1440 return 0;
1441}
1442EXPORT_SYMBOL(tcp_v4_conn_request);
1443
1444
1445/*
1446 * The three way handshake has completed - we got a valid synack -
1447 * now create the new socket.
1448 */
1449struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1450 struct request_sock *req,
1451 struct dst_entry *dst)
1452{
1453 struct inet_request_sock *ireq;
1454 struct inet_sock *newinet;
1455 struct tcp_sock *newtp;
1456 struct sock *newsk;
1457#ifdef CONFIG_TCP_MD5SIG
1458 struct tcp_md5sig_key *key;
1459#endif
1460 struct ip_options_rcu *inet_opt;
1461
1462 if (sk_acceptq_is_full(sk))
1463 goto exit_overflow;
1464
1465 newsk = tcp_create_openreq_child(sk, req, skb);
1466 if (!newsk)
1467 goto exit_nonewsk;
1468
1469 newsk->sk_gso_type = SKB_GSO_TCPV4;
1470
1471 newtp = tcp_sk(newsk);
1472 newinet = inet_sk(newsk);
1473 ireq = inet_rsk(req);
1474 newinet->inet_daddr = ireq->rmt_addr;
1475 newinet->inet_rcv_saddr = ireq->loc_addr;
1476 newinet->inet_saddr = ireq->loc_addr;
1477 inet_opt = ireq->opt;
1478 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1479 ireq->opt = NULL;
1480 newinet->mc_index = inet_iif(skb);
1481 newinet->mc_ttl = ip_hdr(skb)->ttl;
1482 newinet->rcv_tos = ip_hdr(skb)->tos;
1483 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1484 if (inet_opt)
1485 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1486 newinet->inet_id = newtp->write_seq ^ jiffies;
1487
1488 if (!dst) {
1489 dst = inet_csk_route_child_sock(sk, newsk, req);
1490 if (!dst)
1491 goto put_and_exit;
1492 } else {
1493 /* syncookie case : see end of cookie_v4_check() */
1494 }
1495 sk_setup_caps(newsk, dst);
1496
1497 tcp_mtup_init(newsk);
1498 tcp_sync_mss(newsk, dst_mtu(dst));
1499 newtp->advmss = dst_metric_advmss(dst);
1500 if (tcp_sk(sk)->rx_opt.user_mss &&
1501 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1502 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1503
1504 tcp_initialize_rcv_mss(newsk);
1505 if (tcp_rsk(req)->snt_synack)
1506 tcp_valid_rtt_meas(newsk,
1507 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1508 newtp->total_retrans = req->retrans;
1509
1510#ifdef CONFIG_TCP_MD5SIG
1511 /* Copy over the MD5 key from the original socket */
1512 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1513 AF_INET);
1514 if (key != NULL) {
1515 /*
1516 * We're using one, so create a matching key
1517 * on the newsk structure. If we fail to get
1518 * memory, then we end up not copying the key
1519 * across. Shucks.
1520 */
1521 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1522 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1523 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1524 }
1525#endif
1526
1527 if (__inet_inherit_port(sk, newsk) < 0)
1528 goto put_and_exit;
1529 __inet_hash_nolisten(newsk, NULL);
1530
1531 return newsk;
1532
1533exit_overflow:
1534 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1535exit_nonewsk:
1536 dst_release(dst);
1537exit:
1538 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1539 return NULL;
1540put_and_exit:
1541 tcp_clear_xmit_timers(newsk);
1542 tcp_cleanup_congestion_control(newsk);
1543 bh_unlock_sock(newsk);
1544 sock_put(newsk);
1545 goto exit;
1546}
1547EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1548
1549static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1550{
1551 struct tcphdr *th = tcp_hdr(skb);
1552 const struct iphdr *iph = ip_hdr(skb);
1553 struct sock *nsk;
1554 struct request_sock **prev;
1555 /* Find possible connection requests. */
1556 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1557 iph->saddr, iph->daddr);
1558 if (req)
1559 return tcp_check_req(sk, skb, req, prev);
1560
1561 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1562 th->source, iph->daddr, th->dest, inet_iif(skb));
1563
1564 if (nsk) {
1565 if (nsk->sk_state != TCP_TIME_WAIT) {
1566 bh_lock_sock(nsk);
1567 return nsk;
1568 }
1569 inet_twsk_put(inet_twsk(nsk));
1570 return NULL;
1571 }
1572
1573#ifdef CONFIG_SYN_COOKIES
1574 if (!th->syn)
1575 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1576#endif
1577 return sk;
1578}
1579
1580static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1581{
1582 const struct iphdr *iph = ip_hdr(skb);
1583
1584 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1585 if (!tcp_v4_check(skb->len, iph->saddr,
1586 iph->daddr, skb->csum)) {
1587 skb->ip_summed = CHECKSUM_UNNECESSARY;
1588 return 0;
1589 }
1590 }
1591
1592 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1593 skb->len, IPPROTO_TCP, 0);
1594
1595 if (skb->len <= 76) {
1596 return __skb_checksum_complete(skb);
1597 }
1598 return 0;
1599}
1600
1601
1602/* The socket must have it's spinlock held when we get
1603 * here.
1604 *
1605 * We have a potential double-lock case here, so even when
1606 * doing backlog processing we use the BH locking scheme.
1607 * This is because we cannot sleep with the original spinlock
1608 * held.
1609 */
1610int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1611{
1612 struct sock *rsk;
1613#ifdef CONFIG_TCP_MD5SIG
1614 /*
1615 * We really want to reject the packet as early as possible
1616 * if:
1617 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1618 * o There is an MD5 option and we're not expecting one
1619 */
1620 if (tcp_v4_inbound_md5_hash(sk, skb))
1621 goto discard;
1622#endif
1623
1624 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1625 sock_rps_save_rxhash(sk, skb);
1626 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1627 rsk = sk;
1628 goto reset;
1629 }
1630 return 0;
1631 }
1632
1633 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1634 goto csum_err;
1635
1636 if (sk->sk_state == TCP_LISTEN) {
1637 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1638 if (!nsk)
1639 goto discard;
1640
1641 if (nsk != sk) {
1642 sock_rps_save_rxhash(nsk, skb);
1643 if (tcp_child_process(sk, nsk, skb)) {
1644 rsk = nsk;
1645 goto reset;
1646 }
1647 return 0;
1648 }
1649 } else
1650 sock_rps_save_rxhash(sk, skb);
1651
1652 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1653 rsk = sk;
1654 goto reset;
1655 }
1656 return 0;
1657
1658reset:
1659 tcp_v4_send_reset(rsk, skb);
1660discard:
1661 kfree_skb(skb);
1662 /* Be careful here. If this function gets more complicated and
1663 * gcc suffers from register pressure on the x86, sk (in %ebx)
1664 * might be destroyed here. This current version compiles correctly,
1665 * but you have been warned.
1666 */
1667 return 0;
1668
1669csum_err:
1670 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1671 goto discard;
1672}
1673EXPORT_SYMBOL(tcp_v4_do_rcv);
1674
1675/*
1676 * From tcp_input.c
1677 */
1678
1679int tcp_v4_rcv(struct sk_buff *skb)
1680{
1681 const struct iphdr *iph;
1682 const struct tcphdr *th;
1683 struct sock *sk;
1684 int ret;
1685 struct net *net = dev_net(skb->dev);
1686
1687 if (skb->pkt_type != PACKET_HOST)
1688 goto discard_it;
1689
1690 /* Count it even if it's bad */
1691 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1692
1693 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1694 goto discard_it;
1695
1696 th = tcp_hdr(skb);
1697
1698 if (th->doff < sizeof(struct tcphdr) / 4)
1699 goto bad_packet;
1700 if (!pskb_may_pull(skb, th->doff * 4))
1701 goto discard_it;
1702
1703 /* An explanation is required here, I think.
1704 * Packet length and doff are validated by header prediction,
1705 * provided case of th->doff==0 is eliminated.
1706 * So, we defer the checks. */
1707 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1708 goto bad_packet;
1709
1710 th = tcp_hdr(skb);
1711 iph = ip_hdr(skb);
1712 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1713 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1714 skb->len - th->doff * 4);
1715 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1716 TCP_SKB_CB(skb)->when = 0;
1717 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1718 TCP_SKB_CB(skb)->sacked = 0;
1719
1720 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1721 if (!sk)
1722 goto no_tcp_socket;
1723
1724process:
1725 if (sk->sk_state == TCP_TIME_WAIT)
1726 goto do_time_wait;
1727
1728 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1729 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1730 goto discard_and_relse;
1731 }
1732
1733 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1734 goto discard_and_relse;
1735 nf_reset(skb);
1736
1737 if (sk_filter(sk, skb))
1738 goto discard_and_relse;
1739
1740 skb->dev = NULL;
1741
1742 bh_lock_sock_nested(sk);
1743 ret = 0;
1744 if (!sock_owned_by_user(sk)) {
1745#ifdef CONFIG_NET_DMA
1746 struct tcp_sock *tp = tcp_sk(sk);
1747 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1748 tp->ucopy.dma_chan = net_dma_find_channel();
1749 if (tp->ucopy.dma_chan)
1750 ret = tcp_v4_do_rcv(sk, skb);
1751 else
1752#endif
1753 {
1754 if (!tcp_prequeue(sk, skb))
1755 ret = tcp_v4_do_rcv(sk, skb);
1756 }
1757 } else if (unlikely(sk_add_backlog(sk, skb,
1758 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1759 bh_unlock_sock(sk);
1760 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1761 goto discard_and_relse;
1762 }
1763 bh_unlock_sock(sk);
1764
1765 sock_put(sk);
1766
1767 return ret;
1768
1769no_tcp_socket:
1770 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1771 goto discard_it;
1772
1773 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1774bad_packet:
1775 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1776 } else {
1777 tcp_v4_send_reset(NULL, skb);
1778 }
1779
1780discard_it:
1781 /* Discard frame. */
1782 kfree_skb(skb);
1783 return 0;
1784
1785discard_and_relse:
1786 sock_put(sk);
1787 goto discard_it;
1788
1789do_time_wait:
1790 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1791 inet_twsk_put(inet_twsk(sk));
1792 goto discard_it;
1793 }
1794
1795 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1796 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1797 inet_twsk_put(inet_twsk(sk));
1798 goto discard_it;
1799 }
1800 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1801 case TCP_TW_SYN: {
1802 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1803 &tcp_hashinfo,
1804 iph->daddr, th->dest,
1805 inet_iif(skb));
1806 if (sk2) {
1807 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1808 inet_twsk_put(inet_twsk(sk));
1809 sk = sk2;
1810 goto process;
1811 }
1812 /* Fall through to ACK */
1813 }
1814 case TCP_TW_ACK:
1815 tcp_v4_timewait_ack(sk, skb);
1816 break;
1817 case TCP_TW_RST:
1818 goto no_tcp_socket;
1819 case TCP_TW_SUCCESS:;
1820 }
1821 goto discard_it;
1822}
1823
1824struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1825{
1826 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1827 struct inet_sock *inet = inet_sk(sk);
1828 struct inet_peer *peer;
1829
1830 if (!rt ||
1831 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1832 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1833 *release_it = true;
1834 } else {
1835 if (!rt->peer)
1836 rt_bind_peer(rt, inet->inet_daddr, 1);
1837 peer = rt->peer;
1838 *release_it = false;
1839 }
1840
1841 return peer;
1842}
1843EXPORT_SYMBOL(tcp_v4_get_peer);
1844
1845void *tcp_v4_tw_get_peer(struct sock *sk)
1846{
1847 const struct inet_timewait_sock *tw = inet_twsk(sk);
1848
1849 return inet_getpeer_v4(tw->tw_daddr, 1);
1850}
1851EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1852
1853static struct timewait_sock_ops tcp_timewait_sock_ops = {
1854 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1855 .twsk_unique = tcp_twsk_unique,
1856 .twsk_destructor= tcp_twsk_destructor,
1857 .twsk_getpeer = tcp_v4_tw_get_peer,
1858};
1859
1860const struct inet_connection_sock_af_ops ipv4_specific = {
1861 .queue_xmit = ip_queue_xmit,
1862 .send_check = tcp_v4_send_check,
1863 .rebuild_header = inet_sk_rebuild_header,
1864 .conn_request = tcp_v4_conn_request,
1865 .syn_recv_sock = tcp_v4_syn_recv_sock,
1866 .get_peer = tcp_v4_get_peer,
1867 .net_header_len = sizeof(struct iphdr),
1868 .setsockopt = ip_setsockopt,
1869 .getsockopt = ip_getsockopt,
1870 .addr2sockaddr = inet_csk_addr2sockaddr,
1871 .sockaddr_len = sizeof(struct sockaddr_in),
1872 .bind_conflict = inet_csk_bind_conflict,
1873#ifdef CONFIG_COMPAT
1874 .compat_setsockopt = compat_ip_setsockopt,
1875 .compat_getsockopt = compat_ip_getsockopt,
1876#endif
1877};
1878EXPORT_SYMBOL(ipv4_specific);
1879
1880#ifdef CONFIG_TCP_MD5SIG
1881static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1882 .md5_lookup = tcp_v4_md5_lookup,
1883 .calc_md5_hash = tcp_v4_md5_hash_skb,
1884 .md5_parse = tcp_v4_parse_md5_keys,
1885};
1886#endif
1887
1888/* NOTE: A lot of things set to zero explicitly by call to
1889 * sk_alloc() so need not be done here.
1890 */
1891static int tcp_v4_init_sock(struct sock *sk)
1892{
1893 struct inet_connection_sock *icsk = inet_csk(sk);
1894
1895 tcp_init_sock(sk);
1896
1897 icsk->icsk_af_ops = &ipv4_specific;
1898
1899#ifdef CONFIG_TCP_MD5SIG
1900 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1901#endif
1902
1903 return 0;
1904}
1905
1906void tcp_v4_destroy_sock(struct sock *sk)
1907{
1908 struct tcp_sock *tp = tcp_sk(sk);
1909
1910 tcp_clear_xmit_timers(sk);
1911
1912 tcp_cleanup_congestion_control(sk);
1913
1914 /* Cleanup up the write buffer. */
1915 tcp_write_queue_purge(sk);
1916
1917 /* Cleans up our, hopefully empty, out_of_order_queue. */
1918 __skb_queue_purge(&tp->out_of_order_queue);
1919
1920#ifdef CONFIG_TCP_MD5SIG
1921 /* Clean up the MD5 key list, if any */
1922 if (tp->md5sig_info) {
1923 tcp_clear_md5_list(sk);
1924 kfree_rcu(tp->md5sig_info, rcu);
1925 tp->md5sig_info = NULL;
1926 }
1927#endif
1928
1929#ifdef CONFIG_NET_DMA
1930 /* Cleans up our sk_async_wait_queue */
1931 __skb_queue_purge(&sk->sk_async_wait_queue);
1932#endif
1933
1934 /* Clean prequeue, it must be empty really */
1935 __skb_queue_purge(&tp->ucopy.prequeue);
1936
1937 /* Clean up a referenced TCP bind bucket. */
1938 if (inet_csk(sk)->icsk_bind_hash)
1939 inet_put_port(sk);
1940
1941 /*
1942 * If sendmsg cached page exists, toss it.
1943 */
1944 if (sk->sk_sndmsg_page) {
1945 __free_page(sk->sk_sndmsg_page);
1946 sk->sk_sndmsg_page = NULL;
1947 }
1948
1949 /* TCP Cookie Transactions */
1950 if (tp->cookie_values != NULL) {
1951 kref_put(&tp->cookie_values->kref,
1952 tcp_cookie_values_release);
1953 tp->cookie_values = NULL;
1954 }
1955
1956 sk_sockets_allocated_dec(sk);
1957 sock_release_memcg(sk);
1958}
1959EXPORT_SYMBOL(tcp_v4_destroy_sock);
1960
1961#ifdef CONFIG_PROC_FS
1962/* Proc filesystem TCP sock list dumping. */
1963
1964static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1965{
1966 return hlist_nulls_empty(head) ? NULL :
1967 list_entry(head->first, struct inet_timewait_sock, tw_node);
1968}
1969
1970static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1971{
1972 return !is_a_nulls(tw->tw_node.next) ?
1973 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1974}
1975
1976/*
1977 * Get next listener socket follow cur. If cur is NULL, get first socket
1978 * starting from bucket given in st->bucket; when st->bucket is zero the
1979 * very first socket in the hash table is returned.
1980 */
1981static void *listening_get_next(struct seq_file *seq, void *cur)
1982{
1983 struct inet_connection_sock *icsk;
1984 struct hlist_nulls_node *node;
1985 struct sock *sk = cur;
1986 struct inet_listen_hashbucket *ilb;
1987 struct tcp_iter_state *st = seq->private;
1988 struct net *net = seq_file_net(seq);
1989
1990 if (!sk) {
1991 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1992 spin_lock_bh(&ilb->lock);
1993 sk = sk_nulls_head(&ilb->head);
1994 st->offset = 0;
1995 goto get_sk;
1996 }
1997 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1998 ++st->num;
1999 ++st->offset;
2000
2001 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2002 struct request_sock *req = cur;
2003
2004 icsk = inet_csk(st->syn_wait_sk);
2005 req = req->dl_next;
2006 while (1) {
2007 while (req) {
2008 if (req->rsk_ops->family == st->family) {
2009 cur = req;
2010 goto out;
2011 }
2012 req = req->dl_next;
2013 }
2014 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2015 break;
2016get_req:
2017 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2018 }
2019 sk = sk_nulls_next(st->syn_wait_sk);
2020 st->state = TCP_SEQ_STATE_LISTENING;
2021 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2022 } else {
2023 icsk = inet_csk(sk);
2024 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2025 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2026 goto start_req;
2027 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2028 sk = sk_nulls_next(sk);
2029 }
2030get_sk:
2031 sk_nulls_for_each_from(sk, node) {
2032 if (!net_eq(sock_net(sk), net))
2033 continue;
2034 if (sk->sk_family == st->family) {
2035 cur = sk;
2036 goto out;
2037 }
2038 icsk = inet_csk(sk);
2039 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2040 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2041start_req:
2042 st->uid = sock_i_uid(sk);
2043 st->syn_wait_sk = sk;
2044 st->state = TCP_SEQ_STATE_OPENREQ;
2045 st->sbucket = 0;
2046 goto get_req;
2047 }
2048 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2049 }
2050 spin_unlock_bh(&ilb->lock);
2051 st->offset = 0;
2052 if (++st->bucket < INET_LHTABLE_SIZE) {
2053 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2054 spin_lock_bh(&ilb->lock);
2055 sk = sk_nulls_head(&ilb->head);
2056 goto get_sk;
2057 }
2058 cur = NULL;
2059out:
2060 return cur;
2061}
2062
2063static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2064{
2065 struct tcp_iter_state *st = seq->private;
2066 void *rc;
2067
2068 st->bucket = 0;
2069 st->offset = 0;
2070 rc = listening_get_next(seq, NULL);
2071
2072 while (rc && *pos) {
2073 rc = listening_get_next(seq, rc);
2074 --*pos;
2075 }
2076 return rc;
2077}
2078
2079static inline bool empty_bucket(struct tcp_iter_state *st)
2080{
2081 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2082 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2083}
2084
2085/*
2086 * Get first established socket starting from bucket given in st->bucket.
2087 * If st->bucket is zero, the very first socket in the hash is returned.
2088 */
2089static void *established_get_first(struct seq_file *seq)
2090{
2091 struct tcp_iter_state *st = seq->private;
2092 struct net *net = seq_file_net(seq);
2093 void *rc = NULL;
2094
2095 st->offset = 0;
2096 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2097 struct sock *sk;
2098 struct hlist_nulls_node *node;
2099 struct inet_timewait_sock *tw;
2100 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2101
2102 /* Lockless fast path for the common case of empty buckets */
2103 if (empty_bucket(st))
2104 continue;
2105
2106 spin_lock_bh(lock);
2107 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2108 if (sk->sk_family != st->family ||
2109 !net_eq(sock_net(sk), net)) {
2110 continue;
2111 }
2112 rc = sk;
2113 goto out;
2114 }
2115 st->state = TCP_SEQ_STATE_TIME_WAIT;
2116 inet_twsk_for_each(tw, node,
2117 &tcp_hashinfo.ehash[st->bucket].twchain) {
2118 if (tw->tw_family != st->family ||
2119 !net_eq(twsk_net(tw), net)) {
2120 continue;
2121 }
2122 rc = tw;
2123 goto out;
2124 }
2125 spin_unlock_bh(lock);
2126 st->state = TCP_SEQ_STATE_ESTABLISHED;
2127 }
2128out:
2129 return rc;
2130}
2131
2132static void *established_get_next(struct seq_file *seq, void *cur)
2133{
2134 struct sock *sk = cur;
2135 struct inet_timewait_sock *tw;
2136 struct hlist_nulls_node *node;
2137 struct tcp_iter_state *st = seq->private;
2138 struct net *net = seq_file_net(seq);
2139
2140 ++st->num;
2141 ++st->offset;
2142
2143 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2144 tw = cur;
2145 tw = tw_next(tw);
2146get_tw:
2147 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2148 tw = tw_next(tw);
2149 }
2150 if (tw) {
2151 cur = tw;
2152 goto out;
2153 }
2154 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2155 st->state = TCP_SEQ_STATE_ESTABLISHED;
2156
2157 /* Look for next non empty bucket */
2158 st->offset = 0;
2159 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2160 empty_bucket(st))
2161 ;
2162 if (st->bucket > tcp_hashinfo.ehash_mask)
2163 return NULL;
2164
2165 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2166 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2167 } else
2168 sk = sk_nulls_next(sk);
2169
2170 sk_nulls_for_each_from(sk, node) {
2171 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2172 goto found;
2173 }
2174
2175 st->state = TCP_SEQ_STATE_TIME_WAIT;
2176 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2177 goto get_tw;
2178found:
2179 cur = sk;
2180out:
2181 return cur;
2182}
2183
2184static void *established_get_idx(struct seq_file *seq, loff_t pos)
2185{
2186 struct tcp_iter_state *st = seq->private;
2187 void *rc;
2188
2189 st->bucket = 0;
2190 rc = established_get_first(seq);
2191
2192 while (rc && pos) {
2193 rc = established_get_next(seq, rc);
2194 --pos;
2195 }
2196 return rc;
2197}
2198
2199static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2200{
2201 void *rc;
2202 struct tcp_iter_state *st = seq->private;
2203
2204 st->state = TCP_SEQ_STATE_LISTENING;
2205 rc = listening_get_idx(seq, &pos);
2206
2207 if (!rc) {
2208 st->state = TCP_SEQ_STATE_ESTABLISHED;
2209 rc = established_get_idx(seq, pos);
2210 }
2211
2212 return rc;
2213}
2214
2215static void *tcp_seek_last_pos(struct seq_file *seq)
2216{
2217 struct tcp_iter_state *st = seq->private;
2218 int offset = st->offset;
2219 int orig_num = st->num;
2220 void *rc = NULL;
2221
2222 switch (st->state) {
2223 case TCP_SEQ_STATE_OPENREQ:
2224 case TCP_SEQ_STATE_LISTENING:
2225 if (st->bucket >= INET_LHTABLE_SIZE)
2226 break;
2227 st->state = TCP_SEQ_STATE_LISTENING;
2228 rc = listening_get_next(seq, NULL);
2229 while (offset-- && rc)
2230 rc = listening_get_next(seq, rc);
2231 if (rc)
2232 break;
2233 st->bucket = 0;
2234 /* Fallthrough */
2235 case TCP_SEQ_STATE_ESTABLISHED:
2236 case TCP_SEQ_STATE_TIME_WAIT:
2237 st->state = TCP_SEQ_STATE_ESTABLISHED;
2238 if (st->bucket > tcp_hashinfo.ehash_mask)
2239 break;
2240 rc = established_get_first(seq);
2241 while (offset-- && rc)
2242 rc = established_get_next(seq, rc);
2243 }
2244
2245 st->num = orig_num;
2246
2247 return rc;
2248}
2249
2250static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2251{
2252 struct tcp_iter_state *st = seq->private;
2253 void *rc;
2254
2255 if (*pos && *pos == st->last_pos) {
2256 rc = tcp_seek_last_pos(seq);
2257 if (rc)
2258 goto out;
2259 }
2260
2261 st->state = TCP_SEQ_STATE_LISTENING;
2262 st->num = 0;
2263 st->bucket = 0;
2264 st->offset = 0;
2265 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2266
2267out:
2268 st->last_pos = *pos;
2269 return rc;
2270}
2271
2272static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2273{
2274 struct tcp_iter_state *st = seq->private;
2275 void *rc = NULL;
2276
2277 if (v == SEQ_START_TOKEN) {
2278 rc = tcp_get_idx(seq, 0);
2279 goto out;
2280 }
2281
2282 switch (st->state) {
2283 case TCP_SEQ_STATE_OPENREQ:
2284 case TCP_SEQ_STATE_LISTENING:
2285 rc = listening_get_next(seq, v);
2286 if (!rc) {
2287 st->state = TCP_SEQ_STATE_ESTABLISHED;
2288 st->bucket = 0;
2289 st->offset = 0;
2290 rc = established_get_first(seq);
2291 }
2292 break;
2293 case TCP_SEQ_STATE_ESTABLISHED:
2294 case TCP_SEQ_STATE_TIME_WAIT:
2295 rc = established_get_next(seq, v);
2296 break;
2297 }
2298out:
2299 ++*pos;
2300 st->last_pos = *pos;
2301 return rc;
2302}
2303
2304static void tcp_seq_stop(struct seq_file *seq, void *v)
2305{
2306 struct tcp_iter_state *st = seq->private;
2307
2308 switch (st->state) {
2309 case TCP_SEQ_STATE_OPENREQ:
2310 if (v) {
2311 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2312 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2313 }
2314 case TCP_SEQ_STATE_LISTENING:
2315 if (v != SEQ_START_TOKEN)
2316 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2317 break;
2318 case TCP_SEQ_STATE_TIME_WAIT:
2319 case TCP_SEQ_STATE_ESTABLISHED:
2320 if (v)
2321 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2322 break;
2323 }
2324}
2325
2326int tcp_seq_open(struct inode *inode, struct file *file)
2327{
2328 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2329 struct tcp_iter_state *s;
2330 int err;
2331
2332 err = seq_open_net(inode, file, &afinfo->seq_ops,
2333 sizeof(struct tcp_iter_state));
2334 if (err < 0)
2335 return err;
2336
2337 s = ((struct seq_file *)file->private_data)->private;
2338 s->family = afinfo->family;
2339 s->last_pos = 0;
2340 return 0;
2341}
2342EXPORT_SYMBOL(tcp_seq_open);
2343
2344int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2345{
2346 int rc = 0;
2347 struct proc_dir_entry *p;
2348
2349 afinfo->seq_ops.start = tcp_seq_start;
2350 afinfo->seq_ops.next = tcp_seq_next;
2351 afinfo->seq_ops.stop = tcp_seq_stop;
2352
2353 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2354 afinfo->seq_fops, afinfo);
2355 if (!p)
2356 rc = -ENOMEM;
2357 return rc;
2358}
2359EXPORT_SYMBOL(tcp_proc_register);
2360
2361void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2362{
2363 proc_net_remove(net, afinfo->name);
2364}
2365EXPORT_SYMBOL(tcp_proc_unregister);
2366
2367static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2368 struct seq_file *f, int i, int uid, int *len)
2369{
2370 const struct inet_request_sock *ireq = inet_rsk(req);
2371 int ttd = req->expires - jiffies;
2372
2373 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2374 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2375 i,
2376 ireq->loc_addr,
2377 ntohs(inet_sk(sk)->inet_sport),
2378 ireq->rmt_addr,
2379 ntohs(ireq->rmt_port),
2380 TCP_SYN_RECV,
2381 0, 0, /* could print option size, but that is af dependent. */
2382 1, /* timers active (only the expire timer) */
2383 jiffies_to_clock_t(ttd),
2384 req->retrans,
2385 uid,
2386 0, /* non standard timer */
2387 0, /* open_requests have no inode */
2388 atomic_read(&sk->sk_refcnt),
2389 req,
2390 len);
2391}
2392
2393static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2394{
2395 int timer_active;
2396 unsigned long timer_expires;
2397 const struct tcp_sock *tp = tcp_sk(sk);
2398 const struct inet_connection_sock *icsk = inet_csk(sk);
2399 const struct inet_sock *inet = inet_sk(sk);
2400 __be32 dest = inet->inet_daddr;
2401 __be32 src = inet->inet_rcv_saddr;
2402 __u16 destp = ntohs(inet->inet_dport);
2403 __u16 srcp = ntohs(inet->inet_sport);
2404 int rx_queue;
2405
2406 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2407 timer_active = 1;
2408 timer_expires = icsk->icsk_timeout;
2409 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2410 timer_active = 4;
2411 timer_expires = icsk->icsk_timeout;
2412 } else if (timer_pending(&sk->sk_timer)) {
2413 timer_active = 2;
2414 timer_expires = sk->sk_timer.expires;
2415 } else {
2416 timer_active = 0;
2417 timer_expires = jiffies;
2418 }
2419
2420 if (sk->sk_state == TCP_LISTEN)
2421 rx_queue = sk->sk_ack_backlog;
2422 else
2423 /*
2424 * because we dont lock socket, we might find a transient negative value
2425 */
2426 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2427
2428 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2429 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2430 i, src, srcp, dest, destp, sk->sk_state,
2431 tp->write_seq - tp->snd_una,
2432 rx_queue,
2433 timer_active,
2434 jiffies_to_clock_t(timer_expires - jiffies),
2435 icsk->icsk_retransmits,
2436 sock_i_uid(sk),
2437 icsk->icsk_probes_out,
2438 sock_i_ino(sk),
2439 atomic_read(&sk->sk_refcnt), sk,
2440 jiffies_to_clock_t(icsk->icsk_rto),
2441 jiffies_to_clock_t(icsk->icsk_ack.ato),
2442 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2443 tp->snd_cwnd,
2444 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2445 len);
2446}
2447
2448static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2449 struct seq_file *f, int i, int *len)
2450{
2451 __be32 dest, src;
2452 __u16 destp, srcp;
2453 int ttd = tw->tw_ttd - jiffies;
2454
2455 if (ttd < 0)
2456 ttd = 0;
2457
2458 dest = tw->tw_daddr;
2459 src = tw->tw_rcv_saddr;
2460 destp = ntohs(tw->tw_dport);
2461 srcp = ntohs(tw->tw_sport);
2462
2463 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2464 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2465 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2466 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2467 atomic_read(&tw->tw_refcnt), tw, len);
2468}
2469
2470#define TMPSZ 150
2471
2472static int tcp4_seq_show(struct seq_file *seq, void *v)
2473{
2474 struct tcp_iter_state *st;
2475 int len;
2476
2477 if (v == SEQ_START_TOKEN) {
2478 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2479 " sl local_address rem_address st tx_queue "
2480 "rx_queue tr tm->when retrnsmt uid timeout "
2481 "inode");
2482 goto out;
2483 }
2484 st = seq->private;
2485
2486 switch (st->state) {
2487 case TCP_SEQ_STATE_LISTENING:
2488 case TCP_SEQ_STATE_ESTABLISHED:
2489 get_tcp4_sock(v, seq, st->num, &len);
2490 break;
2491 case TCP_SEQ_STATE_OPENREQ:
2492 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2493 break;
2494 case TCP_SEQ_STATE_TIME_WAIT:
2495 get_timewait4_sock(v, seq, st->num, &len);
2496 break;
2497 }
2498 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2499out:
2500 return 0;
2501}
2502
2503static const struct file_operations tcp_afinfo_seq_fops = {
2504 .owner = THIS_MODULE,
2505 .open = tcp_seq_open,
2506 .read = seq_read,
2507 .llseek = seq_lseek,
2508 .release = seq_release_net
2509};
2510
2511static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2512 .name = "tcp",
2513 .family = AF_INET,
2514 .seq_fops = &tcp_afinfo_seq_fops,
2515 .seq_ops = {
2516 .show = tcp4_seq_show,
2517 },
2518};
2519
2520static int __net_init tcp4_proc_init_net(struct net *net)
2521{
2522 return tcp_proc_register(net, &tcp4_seq_afinfo);
2523}
2524
2525static void __net_exit tcp4_proc_exit_net(struct net *net)
2526{
2527 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2528}
2529
2530static struct pernet_operations tcp4_net_ops = {
2531 .init = tcp4_proc_init_net,
2532 .exit = tcp4_proc_exit_net,
2533};
2534
2535int __init tcp4_proc_init(void)
2536{
2537 return register_pernet_subsys(&tcp4_net_ops);
2538}
2539
2540void tcp4_proc_exit(void)
2541{
2542 unregister_pernet_subsys(&tcp4_net_ops);
2543}
2544#endif /* CONFIG_PROC_FS */
2545
2546struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2547{
2548 const struct iphdr *iph = skb_gro_network_header(skb);
2549
2550 switch (skb->ip_summed) {
2551 case CHECKSUM_COMPLETE:
2552 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2553 skb->csum)) {
2554 skb->ip_summed = CHECKSUM_UNNECESSARY;
2555 break;
2556 }
2557
2558 /* fall through */
2559 case CHECKSUM_NONE:
2560 NAPI_GRO_CB(skb)->flush = 1;
2561 return NULL;
2562 }
2563
2564 return tcp_gro_receive(head, skb);
2565}
2566
2567int tcp4_gro_complete(struct sk_buff *skb)
2568{
2569 const struct iphdr *iph = ip_hdr(skb);
2570 struct tcphdr *th = tcp_hdr(skb);
2571
2572 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2573 iph->saddr, iph->daddr, 0);
2574 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2575
2576 return tcp_gro_complete(skb);
2577}
2578
2579struct proto tcp_prot = {
2580 .name = "TCP",
2581 .owner = THIS_MODULE,
2582 .close = tcp_close,
2583 .connect = tcp_v4_connect,
2584 .disconnect = tcp_disconnect,
2585 .accept = inet_csk_accept,
2586 .ioctl = tcp_ioctl,
2587 .init = tcp_v4_init_sock,
2588 .destroy = tcp_v4_destroy_sock,
2589 .shutdown = tcp_shutdown,
2590 .setsockopt = tcp_setsockopt,
2591 .getsockopt = tcp_getsockopt,
2592 .recvmsg = tcp_recvmsg,
2593 .sendmsg = tcp_sendmsg,
2594 .sendpage = tcp_sendpage,
2595 .backlog_rcv = tcp_v4_do_rcv,
2596 .hash = inet_hash,
2597 .unhash = inet_unhash,
2598 .get_port = inet_csk_get_port,
2599 .enter_memory_pressure = tcp_enter_memory_pressure,
2600 .sockets_allocated = &tcp_sockets_allocated,
2601 .orphan_count = &tcp_orphan_count,
2602 .memory_allocated = &tcp_memory_allocated,
2603 .memory_pressure = &tcp_memory_pressure,
2604 .sysctl_wmem = sysctl_tcp_wmem,
2605 .sysctl_rmem = sysctl_tcp_rmem,
2606 .max_header = MAX_TCP_HEADER,
2607 .obj_size = sizeof(struct tcp_sock),
2608 .slab_flags = SLAB_DESTROY_BY_RCU,
2609 .twsk_prot = &tcp_timewait_sock_ops,
2610 .rsk_prot = &tcp_request_sock_ops,
2611 .h.hashinfo = &tcp_hashinfo,
2612 .no_autobind = true,
2613#ifdef CONFIG_COMPAT
2614 .compat_setsockopt = compat_tcp_setsockopt,
2615 .compat_getsockopt = compat_tcp_getsockopt,
2616#endif
2617#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2618 .init_cgroup = tcp_init_cgroup,
2619 .destroy_cgroup = tcp_destroy_cgroup,
2620 .proto_cgroup = tcp_proto_cgroup,
2621#endif
2622};
2623EXPORT_SYMBOL(tcp_prot);
2624
2625static int __net_init tcp_sk_init(struct net *net)
2626{
2627 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2628 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2629}
2630
2631static void __net_exit tcp_sk_exit(struct net *net)
2632{
2633 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2634}
2635
2636static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2637{
2638 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2639}
2640
2641static struct pernet_operations __net_initdata tcp_sk_ops = {
2642 .init = tcp_sk_init,
2643 .exit = tcp_sk_exit,
2644 .exit_batch = tcp_sk_exit_batch,
2645};
2646
2647void __init tcp_v4_init(void)
2648{
2649 inet_hashinfo_init(&tcp_hashinfo);
2650 if (register_pernet_subsys(&tcp_sk_ops))
2651 panic("Failed to create the TCP control socket.\n");
2652}
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#include <linux/sched.h>
61
62#include <net/net_namespace.h>
63#include <net/icmp.h>
64#include <net/inet_hashtables.h>
65#include <net/tcp.h>
66#include <net/transp_v6.h>
67#include <net/ipv6.h>
68#include <net/inet_common.h>
69#include <net/timewait_sock.h>
70#include <net/xfrm.h>
71#include <net/secure_seq.h>
72#include <net/busy_poll.h>
73
74#include <linux/inet.h>
75#include <linux/ipv6.h>
76#include <linux/stddef.h>
77#include <linux/proc_fs.h>
78#include <linux/seq_file.h>
79#include <linux/inetdevice.h>
80#include <linux/btf_ids.h>
81
82#include <crypto/hash.h>
83#include <linux/scatterlist.h>
84
85#include <trace/events/tcp.h>
86
87#ifdef CONFIG_TCP_MD5SIG
88static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
89 __be32 daddr, __be32 saddr, const struct tcphdr *th);
90#endif
91
92struct inet_hashinfo tcp_hashinfo;
93EXPORT_SYMBOL(tcp_hashinfo);
94
95static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
96
97static u32 tcp_v4_init_seq(const struct sk_buff *skb)
98{
99 return secure_tcp_seq(ip_hdr(skb)->daddr,
100 ip_hdr(skb)->saddr,
101 tcp_hdr(skb)->dest,
102 tcp_hdr(skb)->source);
103}
104
105static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
106{
107 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
108}
109
110int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
111{
112 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
113 const struct inet_timewait_sock *tw = inet_twsk(sktw);
114 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
115 struct tcp_sock *tp = tcp_sk(sk);
116
117 if (reuse == 2) {
118 /* Still does not detect *everything* that goes through
119 * lo, since we require a loopback src or dst address
120 * or direct binding to 'lo' interface.
121 */
122 bool loopback = false;
123 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
124 loopback = true;
125#if IS_ENABLED(CONFIG_IPV6)
126 if (tw->tw_family == AF_INET6) {
127 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
129 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
130 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
131 loopback = true;
132 } else
133#endif
134 {
135 if (ipv4_is_loopback(tw->tw_daddr) ||
136 ipv4_is_loopback(tw->tw_rcv_saddr))
137 loopback = true;
138 }
139 if (!loopback)
140 reuse = 0;
141 }
142
143 /* With PAWS, it is safe from the viewpoint
144 of data integrity. Even without PAWS it is safe provided sequence
145 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
146
147 Actually, the idea is close to VJ's one, only timestamp cache is
148 held not per host, but per port pair and TW bucket is used as state
149 holder.
150
151 If TW bucket has been already destroyed we fall back to VJ's scheme
152 and use initial timestamp retrieved from peer table.
153 */
154 if (tcptw->tw_ts_recent_stamp &&
155 (!twp || (reuse && time_after32(ktime_get_seconds(),
156 tcptw->tw_ts_recent_stamp)))) {
157 /* In case of repair and re-using TIME-WAIT sockets we still
158 * want to be sure that it is safe as above but honor the
159 * sequence numbers and time stamps set as part of the repair
160 * process.
161 *
162 * Without this check re-using a TIME-WAIT socket with TCP
163 * repair would accumulate a -1 on the repair assigned
164 * sequence number. The first time it is reused the sequence
165 * is -1, the second time -2, etc. This fixes that issue
166 * without appearing to create any others.
167 */
168 if (likely(!tp->repair)) {
169 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
170
171 if (!seq)
172 seq = 1;
173 WRITE_ONCE(tp->write_seq, seq);
174 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
175 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
176 }
177 sock_hold(sktw);
178 return 1;
179 }
180
181 return 0;
182}
183EXPORT_SYMBOL_GPL(tcp_twsk_unique);
184
185static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
186 int addr_len)
187{
188 /* This check is replicated from tcp_v4_connect() and intended to
189 * prevent BPF program called below from accessing bytes that are out
190 * of the bound specified by user in addr_len.
191 */
192 if (addr_len < sizeof(struct sockaddr_in))
193 return -EINVAL;
194
195 sock_owned_by_me(sk);
196
197 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
198}
199
200/* This will initiate an outgoing connection. */
201int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
202{
203 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
204 struct inet_timewait_death_row *tcp_death_row;
205 struct inet_sock *inet = inet_sk(sk);
206 struct tcp_sock *tp = tcp_sk(sk);
207 struct ip_options_rcu *inet_opt;
208 struct net *net = sock_net(sk);
209 __be16 orig_sport, orig_dport;
210 __be32 daddr, nexthop;
211 struct flowi4 *fl4;
212 struct rtable *rt;
213 int err;
214
215 if (addr_len < sizeof(struct sockaddr_in))
216 return -EINVAL;
217
218 if (usin->sin_family != AF_INET)
219 return -EAFNOSUPPORT;
220
221 nexthop = daddr = usin->sin_addr.s_addr;
222 inet_opt = rcu_dereference_protected(inet->inet_opt,
223 lockdep_sock_is_held(sk));
224 if (inet_opt && inet_opt->opt.srr) {
225 if (!daddr)
226 return -EINVAL;
227 nexthop = inet_opt->opt.faddr;
228 }
229
230 orig_sport = inet->inet_sport;
231 orig_dport = usin->sin_port;
232 fl4 = &inet->cork.fl.u.ip4;
233 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
234 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
235 orig_dport, sk);
236 if (IS_ERR(rt)) {
237 err = PTR_ERR(rt);
238 if (err == -ENETUNREACH)
239 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
240 return err;
241 }
242
243 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
244 ip_rt_put(rt);
245 return -ENETUNREACH;
246 }
247
248 if (!inet_opt || !inet_opt->opt.srr)
249 daddr = fl4->daddr;
250
251 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
252
253 if (!inet->inet_saddr) {
254 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
255 if (err) {
256 ip_rt_put(rt);
257 return err;
258 }
259 } else {
260 sk_rcv_saddr_set(sk, inet->inet_saddr);
261 }
262
263 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
264 /* Reset inherited state */
265 tp->rx_opt.ts_recent = 0;
266 tp->rx_opt.ts_recent_stamp = 0;
267 if (likely(!tp->repair))
268 WRITE_ONCE(tp->write_seq, 0);
269 }
270
271 inet->inet_dport = usin->sin_port;
272 sk_daddr_set(sk, daddr);
273
274 inet_csk(sk)->icsk_ext_hdr_len = 0;
275 if (inet_opt)
276 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
277
278 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
279
280 /* Socket identity is still unknown (sport may be zero).
281 * However we set state to SYN-SENT and not releasing socket
282 * lock select source port, enter ourselves into the hash tables and
283 * complete initialization after this.
284 */
285 tcp_set_state(sk, TCP_SYN_SENT);
286 err = inet_hash_connect(tcp_death_row, sk);
287 if (err)
288 goto failure;
289
290 sk_set_txhash(sk);
291
292 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
293 inet->inet_sport, inet->inet_dport, sk);
294 if (IS_ERR(rt)) {
295 err = PTR_ERR(rt);
296 rt = NULL;
297 goto failure;
298 }
299 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
300 /* OK, now commit destination to socket. */
301 sk->sk_gso_type = SKB_GSO_TCPV4;
302 sk_setup_caps(sk, &rt->dst);
303 rt = NULL;
304
305 if (likely(!tp->repair)) {
306 if (!tp->write_seq)
307 WRITE_ONCE(tp->write_seq,
308 secure_tcp_seq(inet->inet_saddr,
309 inet->inet_daddr,
310 inet->inet_sport,
311 usin->sin_port));
312 WRITE_ONCE(tp->tsoffset,
313 secure_tcp_ts_off(net, inet->inet_saddr,
314 inet->inet_daddr));
315 }
316
317 atomic_set(&inet->inet_id, get_random_u16());
318
319 if (tcp_fastopen_defer_connect(sk, &err))
320 return err;
321 if (err)
322 goto failure;
323
324 err = tcp_connect(sk);
325
326 if (err)
327 goto failure;
328
329 return 0;
330
331failure:
332 /*
333 * This unhashes the socket and releases the local port,
334 * if necessary.
335 */
336 tcp_set_state(sk, TCP_CLOSE);
337 inet_bhash2_reset_saddr(sk);
338 ip_rt_put(rt);
339 sk->sk_route_caps = 0;
340 inet->inet_dport = 0;
341 return err;
342}
343EXPORT_SYMBOL(tcp_v4_connect);
344
345/*
346 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
347 * It can be called through tcp_release_cb() if socket was owned by user
348 * at the time tcp_v4_err() was called to handle ICMP message.
349 */
350void tcp_v4_mtu_reduced(struct sock *sk)
351{
352 struct inet_sock *inet = inet_sk(sk);
353 struct dst_entry *dst;
354 u32 mtu;
355
356 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
357 return;
358 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
359 dst = inet_csk_update_pmtu(sk, mtu);
360 if (!dst)
361 return;
362
363 /* Something is about to be wrong... Remember soft error
364 * for the case, if this connection will not able to recover.
365 */
366 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
367 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
368
369 mtu = dst_mtu(dst);
370
371 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
372 ip_sk_accept_pmtu(sk) &&
373 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
374 tcp_sync_mss(sk, mtu);
375
376 /* Resend the TCP packet because it's
377 * clear that the old packet has been
378 * dropped. This is the new "fast" path mtu
379 * discovery.
380 */
381 tcp_simple_retransmit(sk);
382 } /* else let the usual retransmit timer handle it */
383}
384EXPORT_SYMBOL(tcp_v4_mtu_reduced);
385
386static void do_redirect(struct sk_buff *skb, struct sock *sk)
387{
388 struct dst_entry *dst = __sk_dst_check(sk, 0);
389
390 if (dst)
391 dst->ops->redirect(dst, sk, skb);
392}
393
394
395/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
396void tcp_req_err(struct sock *sk, u32 seq, bool abort)
397{
398 struct request_sock *req = inet_reqsk(sk);
399 struct net *net = sock_net(sk);
400
401 /* ICMPs are not backlogged, hence we cannot get
402 * an established socket here.
403 */
404 if (seq != tcp_rsk(req)->snt_isn) {
405 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
406 } else if (abort) {
407 /*
408 * Still in SYN_RECV, just remove it silently.
409 * There is no good way to pass the error to the newly
410 * created socket, and POSIX does not want network
411 * errors returned from accept().
412 */
413 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
414 tcp_listendrop(req->rsk_listener);
415 }
416 reqsk_put(req);
417}
418EXPORT_SYMBOL(tcp_req_err);
419
420/* TCP-LD (RFC 6069) logic */
421void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
422{
423 struct inet_connection_sock *icsk = inet_csk(sk);
424 struct tcp_sock *tp = tcp_sk(sk);
425 struct sk_buff *skb;
426 s32 remaining;
427 u32 delta_us;
428
429 if (sock_owned_by_user(sk))
430 return;
431
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
433 !icsk->icsk_backoff)
434 return;
435
436 skb = tcp_rtx_queue_head(sk);
437 if (WARN_ON_ONCE(!skb))
438 return;
439
440 icsk->icsk_backoff--;
441 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
442 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
443
444 tcp_mstamp_refresh(tp);
445 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
446 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
447
448 if (remaining > 0) {
449 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
450 remaining, TCP_RTO_MAX);
451 } else {
452 /* RTO revert clocked out retransmission.
453 * Will retransmit now.
454 */
455 tcp_retransmit_timer(sk);
456 }
457}
458EXPORT_SYMBOL(tcp_ld_RTO_revert);
459
460/*
461 * This routine is called by the ICMP module when it gets some
462 * sort of error condition. If err < 0 then the socket should
463 * be closed and the error returned to the user. If err > 0
464 * it's just the icmp type << 8 | icmp code. After adjustment
465 * header points to the first 8 bytes of the tcp header. We need
466 * to find the appropriate port.
467 *
468 * The locking strategy used here is very "optimistic". When
469 * someone else accesses the socket the ICMP is just dropped
470 * and for some paths there is no check at all.
471 * A more general error queue to queue errors for later handling
472 * is probably better.
473 *
474 */
475
476int tcp_v4_err(struct sk_buff *skb, u32 info)
477{
478 const struct iphdr *iph = (const struct iphdr *)skb->data;
479 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
480 struct tcp_sock *tp;
481 const int type = icmp_hdr(skb)->type;
482 const int code = icmp_hdr(skb)->code;
483 struct sock *sk;
484 struct request_sock *fastopen;
485 u32 seq, snd_una;
486 int err;
487 struct net *net = dev_net(skb->dev);
488
489 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
490 iph->daddr, th->dest, iph->saddr,
491 ntohs(th->source), inet_iif(skb), 0);
492 if (!sk) {
493 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
494 return -ENOENT;
495 }
496 if (sk->sk_state == TCP_TIME_WAIT) {
497 /* To increase the counter of ignored icmps for TCP-AO */
498 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
499 inet_twsk_put(inet_twsk(sk));
500 return 0;
501 }
502 seq = ntohl(th->seq);
503 if (sk->sk_state == TCP_NEW_SYN_RECV) {
504 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
505 type == ICMP_TIME_EXCEEDED ||
506 (type == ICMP_DEST_UNREACH &&
507 (code == ICMP_NET_UNREACH ||
508 code == ICMP_HOST_UNREACH)));
509 return 0;
510 }
511
512 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
513 sock_put(sk);
514 return 0;
515 }
516
517 bh_lock_sock(sk);
518 /* If too many ICMPs get dropped on busy
519 * servers this needs to be solved differently.
520 * We do take care of PMTU discovery (RFC1191) special case :
521 * we can receive locally generated ICMP messages while socket is held.
522 */
523 if (sock_owned_by_user(sk)) {
524 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
525 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
526 }
527 if (sk->sk_state == TCP_CLOSE)
528 goto out;
529
530 if (static_branch_unlikely(&ip4_min_ttl)) {
531 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
532 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
533 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
534 goto out;
535 }
536 }
537
538 tp = tcp_sk(sk);
539 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
540 fastopen = rcu_dereference(tp->fastopen_rsk);
541 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
542 if (sk->sk_state != TCP_LISTEN &&
543 !between(seq, snd_una, tp->snd_nxt)) {
544 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
545 goto out;
546 }
547
548 switch (type) {
549 case ICMP_REDIRECT:
550 if (!sock_owned_by_user(sk))
551 do_redirect(skb, sk);
552 goto out;
553 case ICMP_SOURCE_QUENCH:
554 /* Just silently ignore these. */
555 goto out;
556 case ICMP_PARAMETERPROB:
557 err = EPROTO;
558 break;
559 case ICMP_DEST_UNREACH:
560 if (code > NR_ICMP_UNREACH)
561 goto out;
562
563 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
564 /* We are not interested in TCP_LISTEN and open_requests
565 * (SYN-ACKs send out by Linux are always <576bytes so
566 * they should go through unfragmented).
567 */
568 if (sk->sk_state == TCP_LISTEN)
569 goto out;
570
571 WRITE_ONCE(tp->mtu_info, info);
572 if (!sock_owned_by_user(sk)) {
573 tcp_v4_mtu_reduced(sk);
574 } else {
575 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
576 sock_hold(sk);
577 }
578 goto out;
579 }
580
581 err = icmp_err_convert[code].errno;
582 /* check if this ICMP message allows revert of backoff.
583 * (see RFC 6069)
584 */
585 if (!fastopen &&
586 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
587 tcp_ld_RTO_revert(sk, seq);
588 break;
589 case ICMP_TIME_EXCEEDED:
590 err = EHOSTUNREACH;
591 break;
592 default:
593 goto out;
594 }
595
596 switch (sk->sk_state) {
597 case TCP_SYN_SENT:
598 case TCP_SYN_RECV:
599 /* Only in fast or simultaneous open. If a fast open socket is
600 * already accepted it is treated as a connected one below.
601 */
602 if (fastopen && !fastopen->sk)
603 break;
604
605 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
606
607 if (!sock_owned_by_user(sk)) {
608 WRITE_ONCE(sk->sk_err, err);
609
610 sk_error_report(sk);
611
612 tcp_done(sk);
613 } else {
614 WRITE_ONCE(sk->sk_err_soft, err);
615 }
616 goto out;
617 }
618
619 /* If we've already connected we will keep trying
620 * until we time out, or the user gives up.
621 *
622 * rfc1122 4.2.3.9 allows to consider as hard errors
623 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
624 * but it is obsoleted by pmtu discovery).
625 *
626 * Note, that in modern internet, where routing is unreliable
627 * and in each dark corner broken firewalls sit, sending random
628 * errors ordered by their masters even this two messages finally lose
629 * their original sense (even Linux sends invalid PORT_UNREACHs)
630 *
631 * Now we are in compliance with RFCs.
632 * --ANK (980905)
633 */
634
635 if (!sock_owned_by_user(sk) &&
636 inet_test_bit(RECVERR, sk)) {
637 WRITE_ONCE(sk->sk_err, err);
638 sk_error_report(sk);
639 } else { /* Only an error on timeout */
640 WRITE_ONCE(sk->sk_err_soft, err);
641 }
642
643out:
644 bh_unlock_sock(sk);
645 sock_put(sk);
646 return 0;
647}
648
649void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
650{
651 struct tcphdr *th = tcp_hdr(skb);
652
653 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
654 skb->csum_start = skb_transport_header(skb) - skb->head;
655 skb->csum_offset = offsetof(struct tcphdr, check);
656}
657
658/* This routine computes an IPv4 TCP checksum. */
659void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
660{
661 const struct inet_sock *inet = inet_sk(sk);
662
663 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
664}
665EXPORT_SYMBOL(tcp_v4_send_check);
666
667#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
668
669static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
670 const struct tcp_ao_hdr *aoh,
671 struct ip_reply_arg *arg, struct tcphdr *reply,
672 __be32 reply_options[REPLY_OPTIONS_LEN])
673{
674#ifdef CONFIG_TCP_AO
675 int sdif = tcp_v4_sdif(skb);
676 int dif = inet_iif(skb);
677 int l3index = sdif ? dif : 0;
678 bool allocated_traffic_key;
679 struct tcp_ao_key *key;
680 char *traffic_key;
681 bool drop = true;
682 u32 ao_sne = 0;
683 u8 keyid;
684
685 rcu_read_lock();
686 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
687 &key, &traffic_key, &allocated_traffic_key,
688 &keyid, &ao_sne))
689 goto out;
690
691 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
692 (aoh->rnext_keyid << 8) | keyid);
693 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
694 reply->doff = arg->iov[0].iov_len / 4;
695
696 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
697 key, traffic_key,
698 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
699 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
700 reply, ao_sne))
701 goto out;
702 drop = false;
703out:
704 rcu_read_unlock();
705 if (allocated_traffic_key)
706 kfree(traffic_key);
707 return drop;
708#else
709 return true;
710#endif
711}
712
713/*
714 * This routine will send an RST to the other tcp.
715 *
716 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
717 * for reset.
718 * Answer: if a packet caused RST, it is not for a socket
719 * existing in our system, if it is matched to a socket,
720 * it is just duplicate segment or bug in other side's TCP.
721 * So that we build reply only basing on parameters
722 * arrived with segment.
723 * Exception: precedence violation. We do not implement it in any case.
724 */
725
726static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
727{
728 const struct tcphdr *th = tcp_hdr(skb);
729 struct {
730 struct tcphdr th;
731 __be32 opt[REPLY_OPTIONS_LEN];
732 } rep;
733 const __u8 *md5_hash_location = NULL;
734 const struct tcp_ao_hdr *aoh;
735 struct ip_reply_arg arg;
736#ifdef CONFIG_TCP_MD5SIG
737 struct tcp_md5sig_key *key = NULL;
738 unsigned char newhash[16];
739 struct sock *sk1 = NULL;
740 int genhash;
741#endif
742 u64 transmit_time = 0;
743 struct sock *ctl_sk;
744 struct net *net;
745 u32 txhash = 0;
746
747 /* Never send a reset in response to a reset. */
748 if (th->rst)
749 return;
750
751 /* If sk not NULL, it means we did a successful lookup and incoming
752 * route had to be correct. prequeue might have dropped our dst.
753 */
754 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
755 return;
756
757 /* Swap the send and the receive. */
758 memset(&rep, 0, sizeof(rep));
759 rep.th.dest = th->source;
760 rep.th.source = th->dest;
761 rep.th.doff = sizeof(struct tcphdr) / 4;
762 rep.th.rst = 1;
763
764 if (th->ack) {
765 rep.th.seq = th->ack_seq;
766 } else {
767 rep.th.ack = 1;
768 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
769 skb->len - (th->doff << 2));
770 }
771
772 memset(&arg, 0, sizeof(arg));
773 arg.iov[0].iov_base = (unsigned char *)&rep;
774 arg.iov[0].iov_len = sizeof(rep.th);
775
776 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
777
778 /* Invalid TCP option size or twice included auth */
779 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
780 return;
781
782 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
783 return;
784
785#ifdef CONFIG_TCP_MD5SIG
786 rcu_read_lock();
787 if (sk && sk_fullsock(sk)) {
788 const union tcp_md5_addr *addr;
789 int l3index;
790
791 /* sdif set, means packet ingressed via a device
792 * in an L3 domain and inet_iif is set to it.
793 */
794 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
795 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
796 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
797 } else if (md5_hash_location) {
798 const union tcp_md5_addr *addr;
799 int sdif = tcp_v4_sdif(skb);
800 int dif = inet_iif(skb);
801 int l3index;
802
803 /*
804 * active side is lost. Try to find listening socket through
805 * source port, and then find md5 key through listening socket.
806 * we are not loose security here:
807 * Incoming packet is checked with md5 hash with finding key,
808 * no RST generated if md5 hash doesn't match.
809 */
810 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
811 NULL, 0, ip_hdr(skb)->saddr,
812 th->source, ip_hdr(skb)->daddr,
813 ntohs(th->source), dif, sdif);
814 /* don't send rst if it can't find key */
815 if (!sk1)
816 goto out;
817
818 /* sdif set, means packet ingressed via a device
819 * in an L3 domain and dif is set to it.
820 */
821 l3index = sdif ? dif : 0;
822 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
823 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
824 if (!key)
825 goto out;
826
827
828 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
829 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
830 goto out;
831
832 }
833
834 if (key) {
835 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
836 (TCPOPT_NOP << 16) |
837 (TCPOPT_MD5SIG << 8) |
838 TCPOLEN_MD5SIG);
839 /* Update length and the length the header thinks exists */
840 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
841 rep.th.doff = arg.iov[0].iov_len / 4;
842
843 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
844 key, ip_hdr(skb)->saddr,
845 ip_hdr(skb)->daddr, &rep.th);
846 }
847#endif
848 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
849 if (rep.opt[0] == 0) {
850 __be32 mrst = mptcp_reset_option(skb);
851
852 if (mrst) {
853 rep.opt[0] = mrst;
854 arg.iov[0].iov_len += sizeof(mrst);
855 rep.th.doff = arg.iov[0].iov_len / 4;
856 }
857 }
858
859 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
860 ip_hdr(skb)->saddr, /* XXX */
861 arg.iov[0].iov_len, IPPROTO_TCP, 0);
862 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
863 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
864
865 /* When socket is gone, all binding information is lost.
866 * routing might fail in this case. No choice here, if we choose to force
867 * input interface, we will misroute in case of asymmetric route.
868 */
869 if (sk) {
870 arg.bound_dev_if = sk->sk_bound_dev_if;
871 if (sk_fullsock(sk))
872 trace_tcp_send_reset(sk, skb);
873 }
874
875 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
876 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
877
878 arg.tos = ip_hdr(skb)->tos;
879 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
880 local_bh_disable();
881 ctl_sk = this_cpu_read(ipv4_tcp_sk);
882 sock_net_set(ctl_sk, net);
883 if (sk) {
884 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
885 inet_twsk(sk)->tw_mark : sk->sk_mark;
886 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
887 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
888 transmit_time = tcp_transmit_time(sk);
889 xfrm_sk_clone_policy(ctl_sk, sk);
890 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
891 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
892 } else {
893 ctl_sk->sk_mark = 0;
894 ctl_sk->sk_priority = 0;
895 }
896 ip_send_unicast_reply(ctl_sk,
897 skb, &TCP_SKB_CB(skb)->header.h4.opt,
898 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
899 &arg, arg.iov[0].iov_len,
900 transmit_time, txhash);
901
902 xfrm_sk_free_policy(ctl_sk);
903 sock_net_set(ctl_sk, &init_net);
904 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
905 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
906 local_bh_enable();
907
908#ifdef CONFIG_TCP_MD5SIG
909out:
910 rcu_read_unlock();
911#endif
912}
913
914/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
915 outside socket context is ugly, certainly. What can I do?
916 */
917
918static void tcp_v4_send_ack(const struct sock *sk,
919 struct sk_buff *skb, u32 seq, u32 ack,
920 u32 win, u32 tsval, u32 tsecr, int oif,
921 struct tcp_key *key,
922 int reply_flags, u8 tos, u32 txhash)
923{
924 const struct tcphdr *th = tcp_hdr(skb);
925 struct {
926 struct tcphdr th;
927 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
928 } rep;
929 struct net *net = sock_net(sk);
930 struct ip_reply_arg arg;
931 struct sock *ctl_sk;
932 u64 transmit_time;
933
934 memset(&rep.th, 0, sizeof(struct tcphdr));
935 memset(&arg, 0, sizeof(arg));
936
937 arg.iov[0].iov_base = (unsigned char *)&rep;
938 arg.iov[0].iov_len = sizeof(rep.th);
939 if (tsecr) {
940 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
941 (TCPOPT_TIMESTAMP << 8) |
942 TCPOLEN_TIMESTAMP);
943 rep.opt[1] = htonl(tsval);
944 rep.opt[2] = htonl(tsecr);
945 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
946 }
947
948 /* Swap the send and the receive. */
949 rep.th.dest = th->source;
950 rep.th.source = th->dest;
951 rep.th.doff = arg.iov[0].iov_len / 4;
952 rep.th.seq = htonl(seq);
953 rep.th.ack_seq = htonl(ack);
954 rep.th.ack = 1;
955 rep.th.window = htons(win);
956
957#ifdef CONFIG_TCP_MD5SIG
958 if (tcp_key_is_md5(key)) {
959 int offset = (tsecr) ? 3 : 0;
960
961 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
962 (TCPOPT_NOP << 16) |
963 (TCPOPT_MD5SIG << 8) |
964 TCPOLEN_MD5SIG);
965 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
966 rep.th.doff = arg.iov[0].iov_len/4;
967
968 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
969 key->md5_key, ip_hdr(skb)->saddr,
970 ip_hdr(skb)->daddr, &rep.th);
971 }
972#endif
973#ifdef CONFIG_TCP_AO
974 if (tcp_key_is_ao(key)) {
975 int offset = (tsecr) ? 3 : 0;
976
977 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
978 (tcp_ao_len(key->ao_key) << 16) |
979 (key->ao_key->sndid << 8) |
980 key->rcv_next);
981 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
982 rep.th.doff = arg.iov[0].iov_len / 4;
983
984 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
985 key->ao_key, key->traffic_key,
986 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
987 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
988 &rep.th, key->sne);
989 }
990#endif
991 arg.flags = reply_flags;
992 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
993 ip_hdr(skb)->saddr, /* XXX */
994 arg.iov[0].iov_len, IPPROTO_TCP, 0);
995 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
996 if (oif)
997 arg.bound_dev_if = oif;
998 arg.tos = tos;
999 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1000 local_bh_disable();
1001 ctl_sk = this_cpu_read(ipv4_tcp_sk);
1002 sock_net_set(ctl_sk, net);
1003 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1004 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1005 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1006 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1007 transmit_time = tcp_transmit_time(sk);
1008 ip_send_unicast_reply(ctl_sk,
1009 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1010 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1011 &arg, arg.iov[0].iov_len,
1012 transmit_time, txhash);
1013
1014 sock_net_set(ctl_sk, &init_net);
1015 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1016 local_bh_enable();
1017}
1018
1019static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1020{
1021 struct inet_timewait_sock *tw = inet_twsk(sk);
1022 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1023 struct tcp_key key = {};
1024#ifdef CONFIG_TCP_AO
1025 struct tcp_ao_info *ao_info;
1026
1027 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1028 /* FIXME: the segment to-be-acked is not verified yet */
1029 ao_info = rcu_dereference(tcptw->ao_info);
1030 if (ao_info) {
1031 const struct tcp_ao_hdr *aoh;
1032
1033 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1034 inet_twsk_put(tw);
1035 return;
1036 }
1037
1038 if (aoh)
1039 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
1040 }
1041 }
1042 if (key.ao_key) {
1043 struct tcp_ao_key *rnext_key;
1044
1045 key.traffic_key = snd_other_key(key.ao_key);
1046 key.sne = READ_ONCE(ao_info->snd_sne);
1047 rnext_key = READ_ONCE(ao_info->rnext_key);
1048 key.rcv_next = rnext_key->rcvid;
1049 key.type = TCP_KEY_AO;
1050#else
1051 if (0) {
1052#endif
1053#ifdef CONFIG_TCP_MD5SIG
1054 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1055 key.md5_key = tcp_twsk_md5_key(tcptw);
1056 if (key.md5_key)
1057 key.type = TCP_KEY_MD5;
1058#endif
1059 }
1060
1061 tcp_v4_send_ack(sk, skb,
1062 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1063 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1064 tcp_tw_tsval(tcptw),
1065 tcptw->tw_ts_recent,
1066 tw->tw_bound_dev_if, &key,
1067 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1068 tw->tw_tos,
1069 tw->tw_txhash);
1070
1071 inet_twsk_put(tw);
1072}
1073
1074static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1075 struct request_sock *req)
1076{
1077 struct tcp_key key = {};
1078
1079 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1080 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1081 */
1082 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1083 tcp_sk(sk)->snd_nxt;
1084
1085#ifdef CONFIG_TCP_AO
1086 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1087 tcp_rsk_used_ao(req)) {
1088 const union tcp_md5_addr *addr;
1089 const struct tcp_ao_hdr *aoh;
1090 int l3index;
1091
1092 /* Invalid TCP option size or twice included auth */
1093 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1094 return;
1095 if (!aoh)
1096 return;
1097
1098 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1099 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1100 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1101 aoh->rnext_keyid, -1);
1102 if (unlikely(!key.ao_key)) {
1103 /* Send ACK with any matching MKT for the peer */
1104 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1105 /* Matching key disappeared (user removed the key?)
1106 * let the handshake timeout.
1107 */
1108 if (!key.ao_key) {
1109 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1110 addr,
1111 ntohs(tcp_hdr(skb)->source),
1112 &ip_hdr(skb)->daddr,
1113 ntohs(tcp_hdr(skb)->dest));
1114 return;
1115 }
1116 }
1117 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1118 if (!key.traffic_key)
1119 return;
1120
1121 key.type = TCP_KEY_AO;
1122 key.rcv_next = aoh->keyid;
1123 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1124#else
1125 if (0) {
1126#endif
1127#ifdef CONFIG_TCP_MD5SIG
1128 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1129 const union tcp_md5_addr *addr;
1130 int l3index;
1131
1132 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1133 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1134 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1135 if (key.md5_key)
1136 key.type = TCP_KEY_MD5;
1137#endif
1138 }
1139
1140 /* RFC 7323 2.3
1141 * The window field (SEG.WND) of every outgoing segment, with the
1142 * exception of <SYN> segments, MUST be right-shifted by
1143 * Rcv.Wind.Shift bits:
1144 */
1145 tcp_v4_send_ack(sk, skb, seq,
1146 tcp_rsk(req)->rcv_nxt,
1147 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1148 tcp_rsk_tsval(tcp_rsk(req)),
1149 READ_ONCE(req->ts_recent),
1150 0, &key,
1151 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1152 ip_hdr(skb)->tos,
1153 READ_ONCE(tcp_rsk(req)->txhash));
1154 if (tcp_key_is_ao(&key))
1155 kfree(key.traffic_key);
1156}
1157
1158/*
1159 * Send a SYN-ACK after having received a SYN.
1160 * This still operates on a request_sock only, not on a big
1161 * socket.
1162 */
1163static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1164 struct flowi *fl,
1165 struct request_sock *req,
1166 struct tcp_fastopen_cookie *foc,
1167 enum tcp_synack_type synack_type,
1168 struct sk_buff *syn_skb)
1169{
1170 const struct inet_request_sock *ireq = inet_rsk(req);
1171 struct flowi4 fl4;
1172 int err = -1;
1173 struct sk_buff *skb;
1174 u8 tos;
1175
1176 /* First, grab a route. */
1177 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1178 return -1;
1179
1180 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1181
1182 if (skb) {
1183 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1184
1185 tos = READ_ONCE(inet_sk(sk)->tos);
1186
1187 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1188 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1189 (tos & INET_ECN_MASK);
1190
1191 if (!INET_ECN_is_capable(tos) &&
1192 tcp_bpf_ca_needs_ecn((struct sock *)req))
1193 tos |= INET_ECN_ECT_0;
1194
1195 rcu_read_lock();
1196 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1197 ireq->ir_rmt_addr,
1198 rcu_dereference(ireq->ireq_opt),
1199 tos);
1200 rcu_read_unlock();
1201 err = net_xmit_eval(err);
1202 }
1203
1204 return err;
1205}
1206
1207/*
1208 * IPv4 request_sock destructor.
1209 */
1210static void tcp_v4_reqsk_destructor(struct request_sock *req)
1211{
1212 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1213}
1214
1215#ifdef CONFIG_TCP_MD5SIG
1216/*
1217 * RFC2385 MD5 checksumming requires a mapping of
1218 * IP address->MD5 Key.
1219 * We need to maintain these in the sk structure.
1220 */
1221
1222DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1223EXPORT_SYMBOL(tcp_md5_needed);
1224
1225static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1226{
1227 if (!old)
1228 return true;
1229
1230 /* l3index always overrides non-l3index */
1231 if (old->l3index && new->l3index == 0)
1232 return false;
1233 if (old->l3index == 0 && new->l3index)
1234 return true;
1235
1236 return old->prefixlen < new->prefixlen;
1237}
1238
1239/* Find the Key structure for an address. */
1240struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1241 const union tcp_md5_addr *addr,
1242 int family, bool any_l3index)
1243{
1244 const struct tcp_sock *tp = tcp_sk(sk);
1245 struct tcp_md5sig_key *key;
1246 const struct tcp_md5sig_info *md5sig;
1247 __be32 mask;
1248 struct tcp_md5sig_key *best_match = NULL;
1249 bool match;
1250
1251 /* caller either holds rcu_read_lock() or socket lock */
1252 md5sig = rcu_dereference_check(tp->md5sig_info,
1253 lockdep_sock_is_held(sk));
1254 if (!md5sig)
1255 return NULL;
1256
1257 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1258 lockdep_sock_is_held(sk)) {
1259 if (key->family != family)
1260 continue;
1261 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1262 key->l3index != l3index)
1263 continue;
1264 if (family == AF_INET) {
1265 mask = inet_make_mask(key->prefixlen);
1266 match = (key->addr.a4.s_addr & mask) ==
1267 (addr->a4.s_addr & mask);
1268#if IS_ENABLED(CONFIG_IPV6)
1269 } else if (family == AF_INET6) {
1270 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1271 key->prefixlen);
1272#endif
1273 } else {
1274 match = false;
1275 }
1276
1277 if (match && better_md5_match(best_match, key))
1278 best_match = key;
1279 }
1280 return best_match;
1281}
1282EXPORT_SYMBOL(__tcp_md5_do_lookup);
1283
1284static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1285 const union tcp_md5_addr *addr,
1286 int family, u8 prefixlen,
1287 int l3index, u8 flags)
1288{
1289 const struct tcp_sock *tp = tcp_sk(sk);
1290 struct tcp_md5sig_key *key;
1291 unsigned int size = sizeof(struct in_addr);
1292 const struct tcp_md5sig_info *md5sig;
1293
1294 /* caller either holds rcu_read_lock() or socket lock */
1295 md5sig = rcu_dereference_check(tp->md5sig_info,
1296 lockdep_sock_is_held(sk));
1297 if (!md5sig)
1298 return NULL;
1299#if IS_ENABLED(CONFIG_IPV6)
1300 if (family == AF_INET6)
1301 size = sizeof(struct in6_addr);
1302#endif
1303 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1304 lockdep_sock_is_held(sk)) {
1305 if (key->family != family)
1306 continue;
1307 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1308 continue;
1309 if (key->l3index != l3index)
1310 continue;
1311 if (!memcmp(&key->addr, addr, size) &&
1312 key->prefixlen == prefixlen)
1313 return key;
1314 }
1315 return NULL;
1316}
1317
1318struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1319 const struct sock *addr_sk)
1320{
1321 const union tcp_md5_addr *addr;
1322 int l3index;
1323
1324 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1325 addr_sk->sk_bound_dev_if);
1326 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1327 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1328}
1329EXPORT_SYMBOL(tcp_v4_md5_lookup);
1330
1331static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1332{
1333 struct tcp_sock *tp = tcp_sk(sk);
1334 struct tcp_md5sig_info *md5sig;
1335
1336 md5sig = kmalloc(sizeof(*md5sig), gfp);
1337 if (!md5sig)
1338 return -ENOMEM;
1339
1340 sk_gso_disable(sk);
1341 INIT_HLIST_HEAD(&md5sig->head);
1342 rcu_assign_pointer(tp->md5sig_info, md5sig);
1343 return 0;
1344}
1345
1346/* This can be called on a newly created socket, from other files */
1347static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1348 int family, u8 prefixlen, int l3index, u8 flags,
1349 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1350{
1351 /* Add Key to the list */
1352 struct tcp_md5sig_key *key;
1353 struct tcp_sock *tp = tcp_sk(sk);
1354 struct tcp_md5sig_info *md5sig;
1355
1356 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1357 if (key) {
1358 /* Pre-existing entry - just update that one.
1359 * Note that the key might be used concurrently.
1360 * data_race() is telling kcsan that we do not care of
1361 * key mismatches, since changing MD5 key on live flows
1362 * can lead to packet drops.
1363 */
1364 data_race(memcpy(key->key, newkey, newkeylen));
1365
1366 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1367 * Also note that a reader could catch new key->keylen value
1368 * but old key->key[], this is the reason we use __GFP_ZERO
1369 * at sock_kmalloc() time below these lines.
1370 */
1371 WRITE_ONCE(key->keylen, newkeylen);
1372
1373 return 0;
1374 }
1375
1376 md5sig = rcu_dereference_protected(tp->md5sig_info,
1377 lockdep_sock_is_held(sk));
1378
1379 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1380 if (!key)
1381 return -ENOMEM;
1382
1383 memcpy(key->key, newkey, newkeylen);
1384 key->keylen = newkeylen;
1385 key->family = family;
1386 key->prefixlen = prefixlen;
1387 key->l3index = l3index;
1388 key->flags = flags;
1389 memcpy(&key->addr, addr,
1390 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1391 sizeof(struct in_addr));
1392 hlist_add_head_rcu(&key->node, &md5sig->head);
1393 return 0;
1394}
1395
1396int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1397 int family, u8 prefixlen, int l3index, u8 flags,
1398 const u8 *newkey, u8 newkeylen)
1399{
1400 struct tcp_sock *tp = tcp_sk(sk);
1401
1402 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1403 if (tcp_md5_alloc_sigpool())
1404 return -ENOMEM;
1405
1406 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1407 tcp_md5_release_sigpool();
1408 return -ENOMEM;
1409 }
1410
1411 if (!static_branch_inc(&tcp_md5_needed.key)) {
1412 struct tcp_md5sig_info *md5sig;
1413
1414 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1415 rcu_assign_pointer(tp->md5sig_info, NULL);
1416 kfree_rcu(md5sig, rcu);
1417 tcp_md5_release_sigpool();
1418 return -EUSERS;
1419 }
1420 }
1421
1422 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1423 newkey, newkeylen, GFP_KERNEL);
1424}
1425EXPORT_SYMBOL(tcp_md5_do_add);
1426
1427int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1428 int family, u8 prefixlen, int l3index,
1429 struct tcp_md5sig_key *key)
1430{
1431 struct tcp_sock *tp = tcp_sk(sk);
1432
1433 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1434 tcp_md5_add_sigpool();
1435
1436 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1437 tcp_md5_release_sigpool();
1438 return -ENOMEM;
1439 }
1440
1441 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1442 struct tcp_md5sig_info *md5sig;
1443
1444 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1445 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1446 rcu_assign_pointer(tp->md5sig_info, NULL);
1447 kfree_rcu(md5sig, rcu);
1448 tcp_md5_release_sigpool();
1449 return -EUSERS;
1450 }
1451 }
1452
1453 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1454 key->flags, key->key, key->keylen,
1455 sk_gfp_mask(sk, GFP_ATOMIC));
1456}
1457EXPORT_SYMBOL(tcp_md5_key_copy);
1458
1459int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1460 u8 prefixlen, int l3index, u8 flags)
1461{
1462 struct tcp_md5sig_key *key;
1463
1464 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1465 if (!key)
1466 return -ENOENT;
1467 hlist_del_rcu(&key->node);
1468 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1469 kfree_rcu(key, rcu);
1470 return 0;
1471}
1472EXPORT_SYMBOL(tcp_md5_do_del);
1473
1474void tcp_clear_md5_list(struct sock *sk)
1475{
1476 struct tcp_sock *tp = tcp_sk(sk);
1477 struct tcp_md5sig_key *key;
1478 struct hlist_node *n;
1479 struct tcp_md5sig_info *md5sig;
1480
1481 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1482
1483 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1484 hlist_del_rcu(&key->node);
1485 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1486 kfree_rcu(key, rcu);
1487 }
1488}
1489
1490static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1491 sockptr_t optval, int optlen)
1492{
1493 struct tcp_md5sig cmd;
1494 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1495 const union tcp_md5_addr *addr;
1496 u8 prefixlen = 32;
1497 int l3index = 0;
1498 bool l3flag;
1499 u8 flags;
1500
1501 if (optlen < sizeof(cmd))
1502 return -EINVAL;
1503
1504 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1505 return -EFAULT;
1506
1507 if (sin->sin_family != AF_INET)
1508 return -EINVAL;
1509
1510 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1511 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1512
1513 if (optname == TCP_MD5SIG_EXT &&
1514 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1515 prefixlen = cmd.tcpm_prefixlen;
1516 if (prefixlen > 32)
1517 return -EINVAL;
1518 }
1519
1520 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1521 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1522 struct net_device *dev;
1523
1524 rcu_read_lock();
1525 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1526 if (dev && netif_is_l3_master(dev))
1527 l3index = dev->ifindex;
1528
1529 rcu_read_unlock();
1530
1531 /* ok to reference set/not set outside of rcu;
1532 * right now device MUST be an L3 master
1533 */
1534 if (!dev || !l3index)
1535 return -EINVAL;
1536 }
1537
1538 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1539
1540 if (!cmd.tcpm_keylen)
1541 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1542
1543 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1544 return -EINVAL;
1545
1546 /* Don't allow keys for peers that have a matching TCP-AO key.
1547 * See the comment in tcp_ao_add_cmd()
1548 */
1549 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1550 return -EKEYREJECTED;
1551
1552 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1553 cmd.tcpm_key, cmd.tcpm_keylen);
1554}
1555
1556static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1557 __be32 daddr, __be32 saddr,
1558 const struct tcphdr *th, int nbytes)
1559{
1560 struct tcp4_pseudohdr *bp;
1561 struct scatterlist sg;
1562 struct tcphdr *_th;
1563
1564 bp = hp->scratch;
1565 bp->saddr = saddr;
1566 bp->daddr = daddr;
1567 bp->pad = 0;
1568 bp->protocol = IPPROTO_TCP;
1569 bp->len = cpu_to_be16(nbytes);
1570
1571 _th = (struct tcphdr *)(bp + 1);
1572 memcpy(_th, th, sizeof(*th));
1573 _th->check = 0;
1574
1575 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1576 ahash_request_set_crypt(hp->req, &sg, NULL,
1577 sizeof(*bp) + sizeof(*th));
1578 return crypto_ahash_update(hp->req);
1579}
1580
1581static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1582 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1583{
1584 struct tcp_sigpool hp;
1585
1586 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1587 goto clear_hash_nostart;
1588
1589 if (crypto_ahash_init(hp.req))
1590 goto clear_hash;
1591 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1592 goto clear_hash;
1593 if (tcp_md5_hash_key(&hp, key))
1594 goto clear_hash;
1595 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1596 if (crypto_ahash_final(hp.req))
1597 goto clear_hash;
1598
1599 tcp_sigpool_end(&hp);
1600 return 0;
1601
1602clear_hash:
1603 tcp_sigpool_end(&hp);
1604clear_hash_nostart:
1605 memset(md5_hash, 0, 16);
1606 return 1;
1607}
1608
1609int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1610 const struct sock *sk,
1611 const struct sk_buff *skb)
1612{
1613 const struct tcphdr *th = tcp_hdr(skb);
1614 struct tcp_sigpool hp;
1615 __be32 saddr, daddr;
1616
1617 if (sk) { /* valid for establish/request sockets */
1618 saddr = sk->sk_rcv_saddr;
1619 daddr = sk->sk_daddr;
1620 } else {
1621 const struct iphdr *iph = ip_hdr(skb);
1622 saddr = iph->saddr;
1623 daddr = iph->daddr;
1624 }
1625
1626 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1627 goto clear_hash_nostart;
1628
1629 if (crypto_ahash_init(hp.req))
1630 goto clear_hash;
1631
1632 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1633 goto clear_hash;
1634 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1635 goto clear_hash;
1636 if (tcp_md5_hash_key(&hp, key))
1637 goto clear_hash;
1638 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1639 if (crypto_ahash_final(hp.req))
1640 goto clear_hash;
1641
1642 tcp_sigpool_end(&hp);
1643 return 0;
1644
1645clear_hash:
1646 tcp_sigpool_end(&hp);
1647clear_hash_nostart:
1648 memset(md5_hash, 0, 16);
1649 return 1;
1650}
1651EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1652
1653#endif
1654
1655static void tcp_v4_init_req(struct request_sock *req,
1656 const struct sock *sk_listener,
1657 struct sk_buff *skb)
1658{
1659 struct inet_request_sock *ireq = inet_rsk(req);
1660 struct net *net = sock_net(sk_listener);
1661
1662 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1663 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1664 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1665}
1666
1667static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1668 struct sk_buff *skb,
1669 struct flowi *fl,
1670 struct request_sock *req)
1671{
1672 tcp_v4_init_req(req, sk, skb);
1673
1674 if (security_inet_conn_request(sk, skb, req))
1675 return NULL;
1676
1677 return inet_csk_route_req(sk, &fl->u.ip4, req);
1678}
1679
1680struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1681 .family = PF_INET,
1682 .obj_size = sizeof(struct tcp_request_sock),
1683 .rtx_syn_ack = tcp_rtx_synack,
1684 .send_ack = tcp_v4_reqsk_send_ack,
1685 .destructor = tcp_v4_reqsk_destructor,
1686 .send_reset = tcp_v4_send_reset,
1687 .syn_ack_timeout = tcp_syn_ack_timeout,
1688};
1689
1690const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1691 .mss_clamp = TCP_MSS_DEFAULT,
1692#ifdef CONFIG_TCP_MD5SIG
1693 .req_md5_lookup = tcp_v4_md5_lookup,
1694 .calc_md5_hash = tcp_v4_md5_hash_skb,
1695#endif
1696#ifdef CONFIG_TCP_AO
1697 .ao_lookup = tcp_v4_ao_lookup_rsk,
1698 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1699 .ao_synack_hash = tcp_v4_ao_synack_hash,
1700#endif
1701#ifdef CONFIG_SYN_COOKIES
1702 .cookie_init_seq = cookie_v4_init_sequence,
1703#endif
1704 .route_req = tcp_v4_route_req,
1705 .init_seq = tcp_v4_init_seq,
1706 .init_ts_off = tcp_v4_init_ts_off,
1707 .send_synack = tcp_v4_send_synack,
1708};
1709
1710int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1711{
1712 /* Never answer to SYNs send to broadcast or multicast */
1713 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1714 goto drop;
1715
1716 return tcp_conn_request(&tcp_request_sock_ops,
1717 &tcp_request_sock_ipv4_ops, sk, skb);
1718
1719drop:
1720 tcp_listendrop(sk);
1721 return 0;
1722}
1723EXPORT_SYMBOL(tcp_v4_conn_request);
1724
1725
1726/*
1727 * The three way handshake has completed - we got a valid synack -
1728 * now create the new socket.
1729 */
1730struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1731 struct request_sock *req,
1732 struct dst_entry *dst,
1733 struct request_sock *req_unhash,
1734 bool *own_req)
1735{
1736 struct inet_request_sock *ireq;
1737 bool found_dup_sk = false;
1738 struct inet_sock *newinet;
1739 struct tcp_sock *newtp;
1740 struct sock *newsk;
1741#ifdef CONFIG_TCP_MD5SIG
1742 const union tcp_md5_addr *addr;
1743 struct tcp_md5sig_key *key;
1744 int l3index;
1745#endif
1746 struct ip_options_rcu *inet_opt;
1747
1748 if (sk_acceptq_is_full(sk))
1749 goto exit_overflow;
1750
1751 newsk = tcp_create_openreq_child(sk, req, skb);
1752 if (!newsk)
1753 goto exit_nonewsk;
1754
1755 newsk->sk_gso_type = SKB_GSO_TCPV4;
1756 inet_sk_rx_dst_set(newsk, skb);
1757
1758 newtp = tcp_sk(newsk);
1759 newinet = inet_sk(newsk);
1760 ireq = inet_rsk(req);
1761 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1762 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1763 newsk->sk_bound_dev_if = ireq->ir_iif;
1764 newinet->inet_saddr = ireq->ir_loc_addr;
1765 inet_opt = rcu_dereference(ireq->ireq_opt);
1766 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1767 newinet->mc_index = inet_iif(skb);
1768 newinet->mc_ttl = ip_hdr(skb)->ttl;
1769 newinet->rcv_tos = ip_hdr(skb)->tos;
1770 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1771 if (inet_opt)
1772 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1773 atomic_set(&newinet->inet_id, get_random_u16());
1774
1775 /* Set ToS of the new socket based upon the value of incoming SYN.
1776 * ECT bits are set later in tcp_init_transfer().
1777 */
1778 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1779 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1780
1781 if (!dst) {
1782 dst = inet_csk_route_child_sock(sk, newsk, req);
1783 if (!dst)
1784 goto put_and_exit;
1785 } else {
1786 /* syncookie case : see end of cookie_v4_check() */
1787 }
1788 sk_setup_caps(newsk, dst);
1789
1790 tcp_ca_openreq_child(newsk, dst);
1791
1792 tcp_sync_mss(newsk, dst_mtu(dst));
1793 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1794
1795 tcp_initialize_rcv_mss(newsk);
1796
1797#ifdef CONFIG_TCP_MD5SIG
1798 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1799 /* Copy over the MD5 key from the original socket */
1800 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1801 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1802 if (key && !tcp_rsk_used_ao(req)) {
1803 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1804 goto put_and_exit;
1805 sk_gso_disable(newsk);
1806 }
1807#endif
1808#ifdef CONFIG_TCP_AO
1809 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1810 goto put_and_exit; /* OOM, release back memory */
1811#endif
1812
1813 if (__inet_inherit_port(sk, newsk) < 0)
1814 goto put_and_exit;
1815 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1816 &found_dup_sk);
1817 if (likely(*own_req)) {
1818 tcp_move_syn(newtp, req);
1819 ireq->ireq_opt = NULL;
1820 } else {
1821 newinet->inet_opt = NULL;
1822
1823 if (!req_unhash && found_dup_sk) {
1824 /* This code path should only be executed in the
1825 * syncookie case only
1826 */
1827 bh_unlock_sock(newsk);
1828 sock_put(newsk);
1829 newsk = NULL;
1830 }
1831 }
1832 return newsk;
1833
1834exit_overflow:
1835 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1836exit_nonewsk:
1837 dst_release(dst);
1838exit:
1839 tcp_listendrop(sk);
1840 return NULL;
1841put_and_exit:
1842 newinet->inet_opt = NULL;
1843 inet_csk_prepare_forced_close(newsk);
1844 tcp_done(newsk);
1845 goto exit;
1846}
1847EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1848
1849static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1850{
1851#ifdef CONFIG_SYN_COOKIES
1852 const struct tcphdr *th = tcp_hdr(skb);
1853
1854 if (!th->syn)
1855 sk = cookie_v4_check(sk, skb);
1856#endif
1857 return sk;
1858}
1859
1860u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1861 struct tcphdr *th, u32 *cookie)
1862{
1863 u16 mss = 0;
1864#ifdef CONFIG_SYN_COOKIES
1865 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1866 &tcp_request_sock_ipv4_ops, sk, th);
1867 if (mss) {
1868 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1869 tcp_synq_overflow(sk);
1870 }
1871#endif
1872 return mss;
1873}
1874
1875INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1876 u32));
1877/* The socket must have it's spinlock held when we get
1878 * here, unless it is a TCP_LISTEN socket.
1879 *
1880 * We have a potential double-lock case here, so even when
1881 * doing backlog processing we use the BH locking scheme.
1882 * This is because we cannot sleep with the original spinlock
1883 * held.
1884 */
1885int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1886{
1887 enum skb_drop_reason reason;
1888 struct sock *rsk;
1889
1890 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1891 struct dst_entry *dst;
1892
1893 dst = rcu_dereference_protected(sk->sk_rx_dst,
1894 lockdep_sock_is_held(sk));
1895
1896 sock_rps_save_rxhash(sk, skb);
1897 sk_mark_napi_id(sk, skb);
1898 if (dst) {
1899 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1900 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1901 dst, 0)) {
1902 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1903 dst_release(dst);
1904 }
1905 }
1906 tcp_rcv_established(sk, skb);
1907 return 0;
1908 }
1909
1910 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1911 if (tcp_checksum_complete(skb))
1912 goto csum_err;
1913
1914 if (sk->sk_state == TCP_LISTEN) {
1915 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1916
1917 if (!nsk)
1918 goto discard;
1919 if (nsk != sk) {
1920 if (tcp_child_process(sk, nsk, skb)) {
1921 rsk = nsk;
1922 goto reset;
1923 }
1924 return 0;
1925 }
1926 } else
1927 sock_rps_save_rxhash(sk, skb);
1928
1929 if (tcp_rcv_state_process(sk, skb)) {
1930 rsk = sk;
1931 goto reset;
1932 }
1933 return 0;
1934
1935reset:
1936 tcp_v4_send_reset(rsk, skb);
1937discard:
1938 kfree_skb_reason(skb, reason);
1939 /* Be careful here. If this function gets more complicated and
1940 * gcc suffers from register pressure on the x86, sk (in %ebx)
1941 * might be destroyed here. This current version compiles correctly,
1942 * but you have been warned.
1943 */
1944 return 0;
1945
1946csum_err:
1947 reason = SKB_DROP_REASON_TCP_CSUM;
1948 trace_tcp_bad_csum(skb);
1949 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1950 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1951 goto discard;
1952}
1953EXPORT_SYMBOL(tcp_v4_do_rcv);
1954
1955int tcp_v4_early_demux(struct sk_buff *skb)
1956{
1957 struct net *net = dev_net(skb->dev);
1958 const struct iphdr *iph;
1959 const struct tcphdr *th;
1960 struct sock *sk;
1961
1962 if (skb->pkt_type != PACKET_HOST)
1963 return 0;
1964
1965 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1966 return 0;
1967
1968 iph = ip_hdr(skb);
1969 th = tcp_hdr(skb);
1970
1971 if (th->doff < sizeof(struct tcphdr) / 4)
1972 return 0;
1973
1974 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1975 iph->saddr, th->source,
1976 iph->daddr, ntohs(th->dest),
1977 skb->skb_iif, inet_sdif(skb));
1978 if (sk) {
1979 skb->sk = sk;
1980 skb->destructor = sock_edemux;
1981 if (sk_fullsock(sk)) {
1982 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1983
1984 if (dst)
1985 dst = dst_check(dst, 0);
1986 if (dst &&
1987 sk->sk_rx_dst_ifindex == skb->skb_iif)
1988 skb_dst_set_noref(skb, dst);
1989 }
1990 }
1991 return 0;
1992}
1993
1994bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1995 enum skb_drop_reason *reason)
1996{
1997 u32 limit, tail_gso_size, tail_gso_segs;
1998 struct skb_shared_info *shinfo;
1999 const struct tcphdr *th;
2000 struct tcphdr *thtail;
2001 struct sk_buff *tail;
2002 unsigned int hdrlen;
2003 bool fragstolen;
2004 u32 gso_segs;
2005 u32 gso_size;
2006 int delta;
2007
2008 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2009 * we can fix skb->truesize to its real value to avoid future drops.
2010 * This is valid because skb is not yet charged to the socket.
2011 * It has been noticed pure SACK packets were sometimes dropped
2012 * (if cooked by drivers without copybreak feature).
2013 */
2014 skb_condense(skb);
2015
2016 skb_dst_drop(skb);
2017
2018 if (unlikely(tcp_checksum_complete(skb))) {
2019 bh_unlock_sock(sk);
2020 trace_tcp_bad_csum(skb);
2021 *reason = SKB_DROP_REASON_TCP_CSUM;
2022 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2023 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2024 return true;
2025 }
2026
2027 /* Attempt coalescing to last skb in backlog, even if we are
2028 * above the limits.
2029 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2030 */
2031 th = (const struct tcphdr *)skb->data;
2032 hdrlen = th->doff * 4;
2033
2034 tail = sk->sk_backlog.tail;
2035 if (!tail)
2036 goto no_coalesce;
2037 thtail = (struct tcphdr *)tail->data;
2038
2039 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2040 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2041 ((TCP_SKB_CB(tail)->tcp_flags |
2042 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2043 !((TCP_SKB_CB(tail)->tcp_flags &
2044 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2045 ((TCP_SKB_CB(tail)->tcp_flags ^
2046 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2047#ifdef CONFIG_TLS_DEVICE
2048 tail->decrypted != skb->decrypted ||
2049#endif
2050 !mptcp_skb_can_collapse(tail, skb) ||
2051 thtail->doff != th->doff ||
2052 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2053 goto no_coalesce;
2054
2055 __skb_pull(skb, hdrlen);
2056
2057 shinfo = skb_shinfo(skb);
2058 gso_size = shinfo->gso_size ?: skb->len;
2059 gso_segs = shinfo->gso_segs ?: 1;
2060
2061 shinfo = skb_shinfo(tail);
2062 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2063 tail_gso_segs = shinfo->gso_segs ?: 1;
2064
2065 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2066 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2067
2068 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2069 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2070 thtail->window = th->window;
2071 }
2072
2073 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2074 * thtail->fin, so that the fast path in tcp_rcv_established()
2075 * is not entered if we append a packet with a FIN.
2076 * SYN, RST, URG are not present.
2077 * ACK is set on both packets.
2078 * PSH : we do not really care in TCP stack,
2079 * at least for 'GRO' packets.
2080 */
2081 thtail->fin |= th->fin;
2082 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2083
2084 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2085 TCP_SKB_CB(tail)->has_rxtstamp = true;
2086 tail->tstamp = skb->tstamp;
2087 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2088 }
2089
2090 /* Not as strict as GRO. We only need to carry mss max value */
2091 shinfo->gso_size = max(gso_size, tail_gso_size);
2092 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2093
2094 sk->sk_backlog.len += delta;
2095 __NET_INC_STATS(sock_net(sk),
2096 LINUX_MIB_TCPBACKLOGCOALESCE);
2097 kfree_skb_partial(skb, fragstolen);
2098 return false;
2099 }
2100 __skb_push(skb, hdrlen);
2101
2102no_coalesce:
2103 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
2104
2105 /* Only socket owner can try to collapse/prune rx queues
2106 * to reduce memory overhead, so add a little headroom here.
2107 * Few sockets backlog are possibly concurrently non empty.
2108 */
2109 limit += 64 * 1024;
2110
2111 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2112 bh_unlock_sock(sk);
2113 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2114 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2115 return true;
2116 }
2117 return false;
2118}
2119EXPORT_SYMBOL(tcp_add_backlog);
2120
2121int tcp_filter(struct sock *sk, struct sk_buff *skb)
2122{
2123 struct tcphdr *th = (struct tcphdr *)skb->data;
2124
2125 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2126}
2127EXPORT_SYMBOL(tcp_filter);
2128
2129static void tcp_v4_restore_cb(struct sk_buff *skb)
2130{
2131 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2132 sizeof(struct inet_skb_parm));
2133}
2134
2135static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2136 const struct tcphdr *th)
2137{
2138 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2139 * barrier() makes sure compiler wont play fool^Waliasing games.
2140 */
2141 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2142 sizeof(struct inet_skb_parm));
2143 barrier();
2144
2145 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2146 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2147 skb->len - th->doff * 4);
2148 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2149 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2150 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
2151 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2152 TCP_SKB_CB(skb)->sacked = 0;
2153 TCP_SKB_CB(skb)->has_rxtstamp =
2154 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2155}
2156
2157/*
2158 * From tcp_input.c
2159 */
2160
2161int tcp_v4_rcv(struct sk_buff *skb)
2162{
2163 struct net *net = dev_net(skb->dev);
2164 enum skb_drop_reason drop_reason;
2165 int sdif = inet_sdif(skb);
2166 int dif = inet_iif(skb);
2167 const struct iphdr *iph;
2168 const struct tcphdr *th;
2169 bool refcounted;
2170 struct sock *sk;
2171 int ret;
2172
2173 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2174 if (skb->pkt_type != PACKET_HOST)
2175 goto discard_it;
2176
2177 /* Count it even if it's bad */
2178 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2179
2180 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2181 goto discard_it;
2182
2183 th = (const struct tcphdr *)skb->data;
2184
2185 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2186 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2187 goto bad_packet;
2188 }
2189 if (!pskb_may_pull(skb, th->doff * 4))
2190 goto discard_it;
2191
2192 /* An explanation is required here, I think.
2193 * Packet length and doff are validated by header prediction,
2194 * provided case of th->doff==0 is eliminated.
2195 * So, we defer the checks. */
2196
2197 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2198 goto csum_error;
2199
2200 th = (const struct tcphdr *)skb->data;
2201 iph = ip_hdr(skb);
2202lookup:
2203 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2204 skb, __tcp_hdrlen(th), th->source,
2205 th->dest, sdif, &refcounted);
2206 if (!sk)
2207 goto no_tcp_socket;
2208
2209process:
2210 if (sk->sk_state == TCP_TIME_WAIT)
2211 goto do_time_wait;
2212
2213 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2214 struct request_sock *req = inet_reqsk(sk);
2215 bool req_stolen = false;
2216 struct sock *nsk;
2217
2218 sk = req->rsk_listener;
2219 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2220 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2221 else
2222 drop_reason = tcp_inbound_hash(sk, req, skb,
2223 &iph->saddr, &iph->daddr,
2224 AF_INET, dif, sdif);
2225 if (unlikely(drop_reason)) {
2226 sk_drops_add(sk, skb);
2227 reqsk_put(req);
2228 goto discard_it;
2229 }
2230 if (tcp_checksum_complete(skb)) {
2231 reqsk_put(req);
2232 goto csum_error;
2233 }
2234 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2235 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2236 if (!nsk) {
2237 inet_csk_reqsk_queue_drop_and_put(sk, req);
2238 goto lookup;
2239 }
2240 sk = nsk;
2241 /* reuseport_migrate_sock() has already held one sk_refcnt
2242 * before returning.
2243 */
2244 } else {
2245 /* We own a reference on the listener, increase it again
2246 * as we might lose it too soon.
2247 */
2248 sock_hold(sk);
2249 }
2250 refcounted = true;
2251 nsk = NULL;
2252 if (!tcp_filter(sk, skb)) {
2253 th = (const struct tcphdr *)skb->data;
2254 iph = ip_hdr(skb);
2255 tcp_v4_fill_cb(skb, iph, th);
2256 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2257 } else {
2258 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2259 }
2260 if (!nsk) {
2261 reqsk_put(req);
2262 if (req_stolen) {
2263 /* Another cpu got exclusive access to req
2264 * and created a full blown socket.
2265 * Try to feed this packet to this socket
2266 * instead of discarding it.
2267 */
2268 tcp_v4_restore_cb(skb);
2269 sock_put(sk);
2270 goto lookup;
2271 }
2272 goto discard_and_relse;
2273 }
2274 nf_reset_ct(skb);
2275 if (nsk == sk) {
2276 reqsk_put(req);
2277 tcp_v4_restore_cb(skb);
2278 } else if (tcp_child_process(sk, nsk, skb)) {
2279 tcp_v4_send_reset(nsk, skb);
2280 goto discard_and_relse;
2281 } else {
2282 sock_put(sk);
2283 return 0;
2284 }
2285 }
2286
2287 if (static_branch_unlikely(&ip4_min_ttl)) {
2288 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2289 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2290 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2291 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2292 goto discard_and_relse;
2293 }
2294 }
2295
2296 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2297 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2298 goto discard_and_relse;
2299 }
2300
2301 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2302 AF_INET, dif, sdif);
2303 if (drop_reason)
2304 goto discard_and_relse;
2305
2306 nf_reset_ct(skb);
2307
2308 if (tcp_filter(sk, skb)) {
2309 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2310 goto discard_and_relse;
2311 }
2312 th = (const struct tcphdr *)skb->data;
2313 iph = ip_hdr(skb);
2314 tcp_v4_fill_cb(skb, iph, th);
2315
2316 skb->dev = NULL;
2317
2318 if (sk->sk_state == TCP_LISTEN) {
2319 ret = tcp_v4_do_rcv(sk, skb);
2320 goto put_and_return;
2321 }
2322
2323 sk_incoming_cpu_update(sk);
2324
2325 bh_lock_sock_nested(sk);
2326 tcp_segs_in(tcp_sk(sk), skb);
2327 ret = 0;
2328 if (!sock_owned_by_user(sk)) {
2329 ret = tcp_v4_do_rcv(sk, skb);
2330 } else {
2331 if (tcp_add_backlog(sk, skb, &drop_reason))
2332 goto discard_and_relse;
2333 }
2334 bh_unlock_sock(sk);
2335
2336put_and_return:
2337 if (refcounted)
2338 sock_put(sk);
2339
2340 return ret;
2341
2342no_tcp_socket:
2343 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2344 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2345 goto discard_it;
2346
2347 tcp_v4_fill_cb(skb, iph, th);
2348
2349 if (tcp_checksum_complete(skb)) {
2350csum_error:
2351 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2352 trace_tcp_bad_csum(skb);
2353 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2354bad_packet:
2355 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2356 } else {
2357 tcp_v4_send_reset(NULL, skb);
2358 }
2359
2360discard_it:
2361 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2362 /* Discard frame. */
2363 kfree_skb_reason(skb, drop_reason);
2364 return 0;
2365
2366discard_and_relse:
2367 sk_drops_add(sk, skb);
2368 if (refcounted)
2369 sock_put(sk);
2370 goto discard_it;
2371
2372do_time_wait:
2373 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2374 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2375 inet_twsk_put(inet_twsk(sk));
2376 goto discard_it;
2377 }
2378
2379 tcp_v4_fill_cb(skb, iph, th);
2380
2381 if (tcp_checksum_complete(skb)) {
2382 inet_twsk_put(inet_twsk(sk));
2383 goto csum_error;
2384 }
2385 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2386 case TCP_TW_SYN: {
2387 struct sock *sk2 = inet_lookup_listener(net,
2388 net->ipv4.tcp_death_row.hashinfo,
2389 skb, __tcp_hdrlen(th),
2390 iph->saddr, th->source,
2391 iph->daddr, th->dest,
2392 inet_iif(skb),
2393 sdif);
2394 if (sk2) {
2395 inet_twsk_deschedule_put(inet_twsk(sk));
2396 sk = sk2;
2397 tcp_v4_restore_cb(skb);
2398 refcounted = false;
2399 goto process;
2400 }
2401 }
2402 /* to ACK */
2403 fallthrough;
2404 case TCP_TW_ACK:
2405 tcp_v4_timewait_ack(sk, skb);
2406 break;
2407 case TCP_TW_RST:
2408 tcp_v4_send_reset(sk, skb);
2409 inet_twsk_deschedule_put(inet_twsk(sk));
2410 goto discard_it;
2411 case TCP_TW_SUCCESS:;
2412 }
2413 goto discard_it;
2414}
2415
2416static struct timewait_sock_ops tcp_timewait_sock_ops = {
2417 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2418 .twsk_unique = tcp_twsk_unique,
2419 .twsk_destructor= tcp_twsk_destructor,
2420};
2421
2422void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2423{
2424 struct dst_entry *dst = skb_dst(skb);
2425
2426 if (dst && dst_hold_safe(dst)) {
2427 rcu_assign_pointer(sk->sk_rx_dst, dst);
2428 sk->sk_rx_dst_ifindex = skb->skb_iif;
2429 }
2430}
2431EXPORT_SYMBOL(inet_sk_rx_dst_set);
2432
2433const struct inet_connection_sock_af_ops ipv4_specific = {
2434 .queue_xmit = ip_queue_xmit,
2435 .send_check = tcp_v4_send_check,
2436 .rebuild_header = inet_sk_rebuild_header,
2437 .sk_rx_dst_set = inet_sk_rx_dst_set,
2438 .conn_request = tcp_v4_conn_request,
2439 .syn_recv_sock = tcp_v4_syn_recv_sock,
2440 .net_header_len = sizeof(struct iphdr),
2441 .setsockopt = ip_setsockopt,
2442 .getsockopt = ip_getsockopt,
2443 .addr2sockaddr = inet_csk_addr2sockaddr,
2444 .sockaddr_len = sizeof(struct sockaddr_in),
2445 .mtu_reduced = tcp_v4_mtu_reduced,
2446};
2447EXPORT_SYMBOL(ipv4_specific);
2448
2449#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2450static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2451#ifdef CONFIG_TCP_MD5SIG
2452 .md5_lookup = tcp_v4_md5_lookup,
2453 .calc_md5_hash = tcp_v4_md5_hash_skb,
2454 .md5_parse = tcp_v4_parse_md5_keys,
2455#endif
2456#ifdef CONFIG_TCP_AO
2457 .ao_lookup = tcp_v4_ao_lookup,
2458 .calc_ao_hash = tcp_v4_ao_hash_skb,
2459 .ao_parse = tcp_v4_parse_ao,
2460 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2461#endif
2462};
2463#endif
2464
2465/* NOTE: A lot of things set to zero explicitly by call to
2466 * sk_alloc() so need not be done here.
2467 */
2468static int tcp_v4_init_sock(struct sock *sk)
2469{
2470 struct inet_connection_sock *icsk = inet_csk(sk);
2471
2472 tcp_init_sock(sk);
2473
2474 icsk->icsk_af_ops = &ipv4_specific;
2475
2476#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2477 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2478#endif
2479
2480 return 0;
2481}
2482
2483#ifdef CONFIG_TCP_MD5SIG
2484static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2485{
2486 struct tcp_md5sig_info *md5sig;
2487
2488 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2489 kfree(md5sig);
2490 static_branch_slow_dec_deferred(&tcp_md5_needed);
2491 tcp_md5_release_sigpool();
2492}
2493#endif
2494
2495void tcp_v4_destroy_sock(struct sock *sk)
2496{
2497 struct tcp_sock *tp = tcp_sk(sk);
2498
2499 trace_tcp_destroy_sock(sk);
2500
2501 tcp_clear_xmit_timers(sk);
2502
2503 tcp_cleanup_congestion_control(sk);
2504
2505 tcp_cleanup_ulp(sk);
2506
2507 /* Cleanup up the write buffer. */
2508 tcp_write_queue_purge(sk);
2509
2510 /* Check if we want to disable active TFO */
2511 tcp_fastopen_active_disable_ofo_check(sk);
2512
2513 /* Cleans up our, hopefully empty, out_of_order_queue. */
2514 skb_rbtree_purge(&tp->out_of_order_queue);
2515
2516#ifdef CONFIG_TCP_MD5SIG
2517 /* Clean up the MD5 key list, if any */
2518 if (tp->md5sig_info) {
2519 struct tcp_md5sig_info *md5sig;
2520
2521 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2522 tcp_clear_md5_list(sk);
2523 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2524 rcu_assign_pointer(tp->md5sig_info, NULL);
2525 }
2526#endif
2527 tcp_ao_destroy_sock(sk, false);
2528
2529 /* Clean up a referenced TCP bind bucket. */
2530 if (inet_csk(sk)->icsk_bind_hash)
2531 inet_put_port(sk);
2532
2533 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2534
2535 /* If socket is aborted during connect operation */
2536 tcp_free_fastopen_req(tp);
2537 tcp_fastopen_destroy_cipher(sk);
2538 tcp_saved_syn_free(tp);
2539
2540 sk_sockets_allocated_dec(sk);
2541}
2542EXPORT_SYMBOL(tcp_v4_destroy_sock);
2543
2544#ifdef CONFIG_PROC_FS
2545/* Proc filesystem TCP sock list dumping. */
2546
2547static unsigned short seq_file_family(const struct seq_file *seq);
2548
2549static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2550{
2551 unsigned short family = seq_file_family(seq);
2552
2553 /* AF_UNSPEC is used as a match all */
2554 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2555 net_eq(sock_net(sk), seq_file_net(seq)));
2556}
2557
2558/* Find a non empty bucket (starting from st->bucket)
2559 * and return the first sk from it.
2560 */
2561static void *listening_get_first(struct seq_file *seq)
2562{
2563 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2564 struct tcp_iter_state *st = seq->private;
2565
2566 st->offset = 0;
2567 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2568 struct inet_listen_hashbucket *ilb2;
2569 struct hlist_nulls_node *node;
2570 struct sock *sk;
2571
2572 ilb2 = &hinfo->lhash2[st->bucket];
2573 if (hlist_nulls_empty(&ilb2->nulls_head))
2574 continue;
2575
2576 spin_lock(&ilb2->lock);
2577 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2578 if (seq_sk_match(seq, sk))
2579 return sk;
2580 }
2581 spin_unlock(&ilb2->lock);
2582 }
2583
2584 return NULL;
2585}
2586
2587/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2588 * If "cur" is the last one in the st->bucket,
2589 * call listening_get_first() to return the first sk of the next
2590 * non empty bucket.
2591 */
2592static void *listening_get_next(struct seq_file *seq, void *cur)
2593{
2594 struct tcp_iter_state *st = seq->private;
2595 struct inet_listen_hashbucket *ilb2;
2596 struct hlist_nulls_node *node;
2597 struct inet_hashinfo *hinfo;
2598 struct sock *sk = cur;
2599
2600 ++st->num;
2601 ++st->offset;
2602
2603 sk = sk_nulls_next(sk);
2604 sk_nulls_for_each_from(sk, node) {
2605 if (seq_sk_match(seq, sk))
2606 return sk;
2607 }
2608
2609 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2610 ilb2 = &hinfo->lhash2[st->bucket];
2611 spin_unlock(&ilb2->lock);
2612 ++st->bucket;
2613 return listening_get_first(seq);
2614}
2615
2616static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2617{
2618 struct tcp_iter_state *st = seq->private;
2619 void *rc;
2620
2621 st->bucket = 0;
2622 st->offset = 0;
2623 rc = listening_get_first(seq);
2624
2625 while (rc && *pos) {
2626 rc = listening_get_next(seq, rc);
2627 --*pos;
2628 }
2629 return rc;
2630}
2631
2632static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2633 const struct tcp_iter_state *st)
2634{
2635 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2636}
2637
2638/*
2639 * Get first established socket starting from bucket given in st->bucket.
2640 * If st->bucket is zero, the very first socket in the hash is returned.
2641 */
2642static void *established_get_first(struct seq_file *seq)
2643{
2644 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2645 struct tcp_iter_state *st = seq->private;
2646
2647 st->offset = 0;
2648 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2649 struct sock *sk;
2650 struct hlist_nulls_node *node;
2651 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2652
2653 cond_resched();
2654
2655 /* Lockless fast path for the common case of empty buckets */
2656 if (empty_bucket(hinfo, st))
2657 continue;
2658
2659 spin_lock_bh(lock);
2660 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2661 if (seq_sk_match(seq, sk))
2662 return sk;
2663 }
2664 spin_unlock_bh(lock);
2665 }
2666
2667 return NULL;
2668}
2669
2670static void *established_get_next(struct seq_file *seq, void *cur)
2671{
2672 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2673 struct tcp_iter_state *st = seq->private;
2674 struct hlist_nulls_node *node;
2675 struct sock *sk = cur;
2676
2677 ++st->num;
2678 ++st->offset;
2679
2680 sk = sk_nulls_next(sk);
2681
2682 sk_nulls_for_each_from(sk, node) {
2683 if (seq_sk_match(seq, sk))
2684 return sk;
2685 }
2686
2687 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2688 ++st->bucket;
2689 return established_get_first(seq);
2690}
2691
2692static void *established_get_idx(struct seq_file *seq, loff_t pos)
2693{
2694 struct tcp_iter_state *st = seq->private;
2695 void *rc;
2696
2697 st->bucket = 0;
2698 rc = established_get_first(seq);
2699
2700 while (rc && pos) {
2701 rc = established_get_next(seq, rc);
2702 --pos;
2703 }
2704 return rc;
2705}
2706
2707static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2708{
2709 void *rc;
2710 struct tcp_iter_state *st = seq->private;
2711
2712 st->state = TCP_SEQ_STATE_LISTENING;
2713 rc = listening_get_idx(seq, &pos);
2714
2715 if (!rc) {
2716 st->state = TCP_SEQ_STATE_ESTABLISHED;
2717 rc = established_get_idx(seq, pos);
2718 }
2719
2720 return rc;
2721}
2722
2723static void *tcp_seek_last_pos(struct seq_file *seq)
2724{
2725 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2726 struct tcp_iter_state *st = seq->private;
2727 int bucket = st->bucket;
2728 int offset = st->offset;
2729 int orig_num = st->num;
2730 void *rc = NULL;
2731
2732 switch (st->state) {
2733 case TCP_SEQ_STATE_LISTENING:
2734 if (st->bucket > hinfo->lhash2_mask)
2735 break;
2736 rc = listening_get_first(seq);
2737 while (offset-- && rc && bucket == st->bucket)
2738 rc = listening_get_next(seq, rc);
2739 if (rc)
2740 break;
2741 st->bucket = 0;
2742 st->state = TCP_SEQ_STATE_ESTABLISHED;
2743 fallthrough;
2744 case TCP_SEQ_STATE_ESTABLISHED:
2745 if (st->bucket > hinfo->ehash_mask)
2746 break;
2747 rc = established_get_first(seq);
2748 while (offset-- && rc && bucket == st->bucket)
2749 rc = established_get_next(seq, rc);
2750 }
2751
2752 st->num = orig_num;
2753
2754 return rc;
2755}
2756
2757void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2758{
2759 struct tcp_iter_state *st = seq->private;
2760 void *rc;
2761
2762 if (*pos && *pos == st->last_pos) {
2763 rc = tcp_seek_last_pos(seq);
2764 if (rc)
2765 goto out;
2766 }
2767
2768 st->state = TCP_SEQ_STATE_LISTENING;
2769 st->num = 0;
2770 st->bucket = 0;
2771 st->offset = 0;
2772 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2773
2774out:
2775 st->last_pos = *pos;
2776 return rc;
2777}
2778EXPORT_SYMBOL(tcp_seq_start);
2779
2780void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2781{
2782 struct tcp_iter_state *st = seq->private;
2783 void *rc = NULL;
2784
2785 if (v == SEQ_START_TOKEN) {
2786 rc = tcp_get_idx(seq, 0);
2787 goto out;
2788 }
2789
2790 switch (st->state) {
2791 case TCP_SEQ_STATE_LISTENING:
2792 rc = listening_get_next(seq, v);
2793 if (!rc) {
2794 st->state = TCP_SEQ_STATE_ESTABLISHED;
2795 st->bucket = 0;
2796 st->offset = 0;
2797 rc = established_get_first(seq);
2798 }
2799 break;
2800 case TCP_SEQ_STATE_ESTABLISHED:
2801 rc = established_get_next(seq, v);
2802 break;
2803 }
2804out:
2805 ++*pos;
2806 st->last_pos = *pos;
2807 return rc;
2808}
2809EXPORT_SYMBOL(tcp_seq_next);
2810
2811void tcp_seq_stop(struct seq_file *seq, void *v)
2812{
2813 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2814 struct tcp_iter_state *st = seq->private;
2815
2816 switch (st->state) {
2817 case TCP_SEQ_STATE_LISTENING:
2818 if (v != SEQ_START_TOKEN)
2819 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2820 break;
2821 case TCP_SEQ_STATE_ESTABLISHED:
2822 if (v)
2823 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2824 break;
2825 }
2826}
2827EXPORT_SYMBOL(tcp_seq_stop);
2828
2829static void get_openreq4(const struct request_sock *req,
2830 struct seq_file *f, int i)
2831{
2832 const struct inet_request_sock *ireq = inet_rsk(req);
2833 long delta = req->rsk_timer.expires - jiffies;
2834
2835 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2836 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2837 i,
2838 ireq->ir_loc_addr,
2839 ireq->ir_num,
2840 ireq->ir_rmt_addr,
2841 ntohs(ireq->ir_rmt_port),
2842 TCP_SYN_RECV,
2843 0, 0, /* could print option size, but that is af dependent. */
2844 1, /* timers active (only the expire timer) */
2845 jiffies_delta_to_clock_t(delta),
2846 req->num_timeout,
2847 from_kuid_munged(seq_user_ns(f),
2848 sock_i_uid(req->rsk_listener)),
2849 0, /* non standard timer */
2850 0, /* open_requests have no inode */
2851 0,
2852 req);
2853}
2854
2855static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2856{
2857 int timer_active;
2858 unsigned long timer_expires;
2859 const struct tcp_sock *tp = tcp_sk(sk);
2860 const struct inet_connection_sock *icsk = inet_csk(sk);
2861 const struct inet_sock *inet = inet_sk(sk);
2862 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2863 __be32 dest = inet->inet_daddr;
2864 __be32 src = inet->inet_rcv_saddr;
2865 __u16 destp = ntohs(inet->inet_dport);
2866 __u16 srcp = ntohs(inet->inet_sport);
2867 int rx_queue;
2868 int state;
2869
2870 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2871 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2872 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2873 timer_active = 1;
2874 timer_expires = icsk->icsk_timeout;
2875 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2876 timer_active = 4;
2877 timer_expires = icsk->icsk_timeout;
2878 } else if (timer_pending(&sk->sk_timer)) {
2879 timer_active = 2;
2880 timer_expires = sk->sk_timer.expires;
2881 } else {
2882 timer_active = 0;
2883 timer_expires = jiffies;
2884 }
2885
2886 state = inet_sk_state_load(sk);
2887 if (state == TCP_LISTEN)
2888 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2889 else
2890 /* Because we don't lock the socket,
2891 * we might find a transient negative value.
2892 */
2893 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2894 READ_ONCE(tp->copied_seq), 0);
2895
2896 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2897 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2898 i, src, srcp, dest, destp, state,
2899 READ_ONCE(tp->write_seq) - tp->snd_una,
2900 rx_queue,
2901 timer_active,
2902 jiffies_delta_to_clock_t(timer_expires - jiffies),
2903 icsk->icsk_retransmits,
2904 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2905 icsk->icsk_probes_out,
2906 sock_i_ino(sk),
2907 refcount_read(&sk->sk_refcnt), sk,
2908 jiffies_to_clock_t(icsk->icsk_rto),
2909 jiffies_to_clock_t(icsk->icsk_ack.ato),
2910 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2911 tcp_snd_cwnd(tp),
2912 state == TCP_LISTEN ?
2913 fastopenq->max_qlen :
2914 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2915}
2916
2917static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2918 struct seq_file *f, int i)
2919{
2920 long delta = tw->tw_timer.expires - jiffies;
2921 __be32 dest, src;
2922 __u16 destp, srcp;
2923
2924 dest = tw->tw_daddr;
2925 src = tw->tw_rcv_saddr;
2926 destp = ntohs(tw->tw_dport);
2927 srcp = ntohs(tw->tw_sport);
2928
2929 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2930 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2931 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2932 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2933 refcount_read(&tw->tw_refcnt), tw);
2934}
2935
2936#define TMPSZ 150
2937
2938static int tcp4_seq_show(struct seq_file *seq, void *v)
2939{
2940 struct tcp_iter_state *st;
2941 struct sock *sk = v;
2942
2943 seq_setwidth(seq, TMPSZ - 1);
2944 if (v == SEQ_START_TOKEN) {
2945 seq_puts(seq, " sl local_address rem_address st tx_queue "
2946 "rx_queue tr tm->when retrnsmt uid timeout "
2947 "inode");
2948 goto out;
2949 }
2950 st = seq->private;
2951
2952 if (sk->sk_state == TCP_TIME_WAIT)
2953 get_timewait4_sock(v, seq, st->num);
2954 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2955 get_openreq4(v, seq, st->num);
2956 else
2957 get_tcp4_sock(v, seq, st->num);
2958out:
2959 seq_pad(seq, '\n');
2960 return 0;
2961}
2962
2963#ifdef CONFIG_BPF_SYSCALL
2964struct bpf_tcp_iter_state {
2965 struct tcp_iter_state state;
2966 unsigned int cur_sk;
2967 unsigned int end_sk;
2968 unsigned int max_sk;
2969 struct sock **batch;
2970 bool st_bucket_done;
2971};
2972
2973struct bpf_iter__tcp {
2974 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2975 __bpf_md_ptr(struct sock_common *, sk_common);
2976 uid_t uid __aligned(8);
2977};
2978
2979static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2980 struct sock_common *sk_common, uid_t uid)
2981{
2982 struct bpf_iter__tcp ctx;
2983
2984 meta->seq_num--; /* skip SEQ_START_TOKEN */
2985 ctx.meta = meta;
2986 ctx.sk_common = sk_common;
2987 ctx.uid = uid;
2988 return bpf_iter_run_prog(prog, &ctx);
2989}
2990
2991static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2992{
2993 while (iter->cur_sk < iter->end_sk)
2994 sock_gen_put(iter->batch[iter->cur_sk++]);
2995}
2996
2997static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2998 unsigned int new_batch_sz)
2999{
3000 struct sock **new_batch;
3001
3002 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3003 GFP_USER | __GFP_NOWARN);
3004 if (!new_batch)
3005 return -ENOMEM;
3006
3007 bpf_iter_tcp_put_batch(iter);
3008 kvfree(iter->batch);
3009 iter->batch = new_batch;
3010 iter->max_sk = new_batch_sz;
3011
3012 return 0;
3013}
3014
3015static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3016 struct sock *start_sk)
3017{
3018 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3019 struct bpf_tcp_iter_state *iter = seq->private;
3020 struct tcp_iter_state *st = &iter->state;
3021 struct hlist_nulls_node *node;
3022 unsigned int expected = 1;
3023 struct sock *sk;
3024
3025 sock_hold(start_sk);
3026 iter->batch[iter->end_sk++] = start_sk;
3027
3028 sk = sk_nulls_next(start_sk);
3029 sk_nulls_for_each_from(sk, node) {
3030 if (seq_sk_match(seq, sk)) {
3031 if (iter->end_sk < iter->max_sk) {
3032 sock_hold(sk);
3033 iter->batch[iter->end_sk++] = sk;
3034 }
3035 expected++;
3036 }
3037 }
3038 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3039
3040 return expected;
3041}
3042
3043static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3044 struct sock *start_sk)
3045{
3046 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3047 struct bpf_tcp_iter_state *iter = seq->private;
3048 struct tcp_iter_state *st = &iter->state;
3049 struct hlist_nulls_node *node;
3050 unsigned int expected = 1;
3051 struct sock *sk;
3052
3053 sock_hold(start_sk);
3054 iter->batch[iter->end_sk++] = start_sk;
3055
3056 sk = sk_nulls_next(start_sk);
3057 sk_nulls_for_each_from(sk, node) {
3058 if (seq_sk_match(seq, sk)) {
3059 if (iter->end_sk < iter->max_sk) {
3060 sock_hold(sk);
3061 iter->batch[iter->end_sk++] = sk;
3062 }
3063 expected++;
3064 }
3065 }
3066 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3067
3068 return expected;
3069}
3070
3071static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3072{
3073 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3074 struct bpf_tcp_iter_state *iter = seq->private;
3075 struct tcp_iter_state *st = &iter->state;
3076 unsigned int expected;
3077 bool resized = false;
3078 struct sock *sk;
3079
3080 /* The st->bucket is done. Directly advance to the next
3081 * bucket instead of having the tcp_seek_last_pos() to skip
3082 * one by one in the current bucket and eventually find out
3083 * it has to advance to the next bucket.
3084 */
3085 if (iter->st_bucket_done) {
3086 st->offset = 0;
3087 st->bucket++;
3088 if (st->state == TCP_SEQ_STATE_LISTENING &&
3089 st->bucket > hinfo->lhash2_mask) {
3090 st->state = TCP_SEQ_STATE_ESTABLISHED;
3091 st->bucket = 0;
3092 }
3093 }
3094
3095again:
3096 /* Get a new batch */
3097 iter->cur_sk = 0;
3098 iter->end_sk = 0;
3099 iter->st_bucket_done = false;
3100
3101 sk = tcp_seek_last_pos(seq);
3102 if (!sk)
3103 return NULL; /* Done */
3104
3105 if (st->state == TCP_SEQ_STATE_LISTENING)
3106 expected = bpf_iter_tcp_listening_batch(seq, sk);
3107 else
3108 expected = bpf_iter_tcp_established_batch(seq, sk);
3109
3110 if (iter->end_sk == expected) {
3111 iter->st_bucket_done = true;
3112 return sk;
3113 }
3114
3115 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3116 resized = true;
3117 goto again;
3118 }
3119
3120 return sk;
3121}
3122
3123static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3124{
3125 /* bpf iter does not support lseek, so it always
3126 * continue from where it was stop()-ped.
3127 */
3128 if (*pos)
3129 return bpf_iter_tcp_batch(seq);
3130
3131 return SEQ_START_TOKEN;
3132}
3133
3134static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3135{
3136 struct bpf_tcp_iter_state *iter = seq->private;
3137 struct tcp_iter_state *st = &iter->state;
3138 struct sock *sk;
3139
3140 /* Whenever seq_next() is called, the iter->cur_sk is
3141 * done with seq_show(), so advance to the next sk in
3142 * the batch.
3143 */
3144 if (iter->cur_sk < iter->end_sk) {
3145 /* Keeping st->num consistent in tcp_iter_state.
3146 * bpf_iter_tcp does not use st->num.
3147 * meta.seq_num is used instead.
3148 */
3149 st->num++;
3150 /* Move st->offset to the next sk in the bucket such that
3151 * the future start() will resume at st->offset in
3152 * st->bucket. See tcp_seek_last_pos().
3153 */
3154 st->offset++;
3155 sock_gen_put(iter->batch[iter->cur_sk++]);
3156 }
3157
3158 if (iter->cur_sk < iter->end_sk)
3159 sk = iter->batch[iter->cur_sk];
3160 else
3161 sk = bpf_iter_tcp_batch(seq);
3162
3163 ++*pos;
3164 /* Keeping st->last_pos consistent in tcp_iter_state.
3165 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3166 */
3167 st->last_pos = *pos;
3168 return sk;
3169}
3170
3171static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3172{
3173 struct bpf_iter_meta meta;
3174 struct bpf_prog *prog;
3175 struct sock *sk = v;
3176 uid_t uid;
3177 int ret;
3178
3179 if (v == SEQ_START_TOKEN)
3180 return 0;
3181
3182 if (sk_fullsock(sk))
3183 lock_sock(sk);
3184
3185 if (unlikely(sk_unhashed(sk))) {
3186 ret = SEQ_SKIP;
3187 goto unlock;
3188 }
3189
3190 if (sk->sk_state == TCP_TIME_WAIT) {
3191 uid = 0;
3192 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3193 const struct request_sock *req = v;
3194
3195 uid = from_kuid_munged(seq_user_ns(seq),
3196 sock_i_uid(req->rsk_listener));
3197 } else {
3198 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3199 }
3200
3201 meta.seq = seq;
3202 prog = bpf_iter_get_info(&meta, false);
3203 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3204
3205unlock:
3206 if (sk_fullsock(sk))
3207 release_sock(sk);
3208 return ret;
3209
3210}
3211
3212static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3213{
3214 struct bpf_tcp_iter_state *iter = seq->private;
3215 struct bpf_iter_meta meta;
3216 struct bpf_prog *prog;
3217
3218 if (!v) {
3219 meta.seq = seq;
3220 prog = bpf_iter_get_info(&meta, true);
3221 if (prog)
3222 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3223 }
3224
3225 if (iter->cur_sk < iter->end_sk) {
3226 bpf_iter_tcp_put_batch(iter);
3227 iter->st_bucket_done = false;
3228 }
3229}
3230
3231static const struct seq_operations bpf_iter_tcp_seq_ops = {
3232 .show = bpf_iter_tcp_seq_show,
3233 .start = bpf_iter_tcp_seq_start,
3234 .next = bpf_iter_tcp_seq_next,
3235 .stop = bpf_iter_tcp_seq_stop,
3236};
3237#endif
3238static unsigned short seq_file_family(const struct seq_file *seq)
3239{
3240 const struct tcp_seq_afinfo *afinfo;
3241
3242#ifdef CONFIG_BPF_SYSCALL
3243 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3244 if (seq->op == &bpf_iter_tcp_seq_ops)
3245 return AF_UNSPEC;
3246#endif
3247
3248 /* Iterated from proc fs */
3249 afinfo = pde_data(file_inode(seq->file));
3250 return afinfo->family;
3251}
3252
3253static const struct seq_operations tcp4_seq_ops = {
3254 .show = tcp4_seq_show,
3255 .start = tcp_seq_start,
3256 .next = tcp_seq_next,
3257 .stop = tcp_seq_stop,
3258};
3259
3260static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3261 .family = AF_INET,
3262};
3263
3264static int __net_init tcp4_proc_init_net(struct net *net)
3265{
3266 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3267 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3268 return -ENOMEM;
3269 return 0;
3270}
3271
3272static void __net_exit tcp4_proc_exit_net(struct net *net)
3273{
3274 remove_proc_entry("tcp", net->proc_net);
3275}
3276
3277static struct pernet_operations tcp4_net_ops = {
3278 .init = tcp4_proc_init_net,
3279 .exit = tcp4_proc_exit_net,
3280};
3281
3282int __init tcp4_proc_init(void)
3283{
3284 return register_pernet_subsys(&tcp4_net_ops);
3285}
3286
3287void tcp4_proc_exit(void)
3288{
3289 unregister_pernet_subsys(&tcp4_net_ops);
3290}
3291#endif /* CONFIG_PROC_FS */
3292
3293/* @wake is one when sk_stream_write_space() calls us.
3294 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3295 * This mimics the strategy used in sock_def_write_space().
3296 */
3297bool tcp_stream_memory_free(const struct sock *sk, int wake)
3298{
3299 const struct tcp_sock *tp = tcp_sk(sk);
3300 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3301 READ_ONCE(tp->snd_nxt);
3302
3303 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3304}
3305EXPORT_SYMBOL(tcp_stream_memory_free);
3306
3307struct proto tcp_prot = {
3308 .name = "TCP",
3309 .owner = THIS_MODULE,
3310 .close = tcp_close,
3311 .pre_connect = tcp_v4_pre_connect,
3312 .connect = tcp_v4_connect,
3313 .disconnect = tcp_disconnect,
3314 .accept = inet_csk_accept,
3315 .ioctl = tcp_ioctl,
3316 .init = tcp_v4_init_sock,
3317 .destroy = tcp_v4_destroy_sock,
3318 .shutdown = tcp_shutdown,
3319 .setsockopt = tcp_setsockopt,
3320 .getsockopt = tcp_getsockopt,
3321 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3322 .keepalive = tcp_set_keepalive,
3323 .recvmsg = tcp_recvmsg,
3324 .sendmsg = tcp_sendmsg,
3325 .splice_eof = tcp_splice_eof,
3326 .backlog_rcv = tcp_v4_do_rcv,
3327 .release_cb = tcp_release_cb,
3328 .hash = inet_hash,
3329 .unhash = inet_unhash,
3330 .get_port = inet_csk_get_port,
3331 .put_port = inet_put_port,
3332#ifdef CONFIG_BPF_SYSCALL
3333 .psock_update_sk_prot = tcp_bpf_update_proto,
3334#endif
3335 .enter_memory_pressure = tcp_enter_memory_pressure,
3336 .leave_memory_pressure = tcp_leave_memory_pressure,
3337 .stream_memory_free = tcp_stream_memory_free,
3338 .sockets_allocated = &tcp_sockets_allocated,
3339 .orphan_count = &tcp_orphan_count,
3340
3341 .memory_allocated = &tcp_memory_allocated,
3342 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3343
3344 .memory_pressure = &tcp_memory_pressure,
3345 .sysctl_mem = sysctl_tcp_mem,
3346 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3347 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3348 .max_header = MAX_TCP_HEADER,
3349 .obj_size = sizeof(struct tcp_sock),
3350 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3351 .twsk_prot = &tcp_timewait_sock_ops,
3352 .rsk_prot = &tcp_request_sock_ops,
3353 .h.hashinfo = NULL,
3354 .no_autobind = true,
3355 .diag_destroy = tcp_abort,
3356};
3357EXPORT_SYMBOL(tcp_prot);
3358
3359static void __net_exit tcp_sk_exit(struct net *net)
3360{
3361 if (net->ipv4.tcp_congestion_control)
3362 bpf_module_put(net->ipv4.tcp_congestion_control,
3363 net->ipv4.tcp_congestion_control->owner);
3364}
3365
3366static void __net_init tcp_set_hashinfo(struct net *net)
3367{
3368 struct inet_hashinfo *hinfo;
3369 unsigned int ehash_entries;
3370 struct net *old_net;
3371
3372 if (net_eq(net, &init_net))
3373 goto fallback;
3374
3375 old_net = current->nsproxy->net_ns;
3376 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3377 if (!ehash_entries)
3378 goto fallback;
3379
3380 ehash_entries = roundup_pow_of_two(ehash_entries);
3381 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3382 if (!hinfo) {
3383 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3384 "for a netns, fallback to the global one\n",
3385 ehash_entries);
3386fallback:
3387 hinfo = &tcp_hashinfo;
3388 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3389 }
3390
3391 net->ipv4.tcp_death_row.hashinfo = hinfo;
3392 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3393 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3394}
3395
3396static int __net_init tcp_sk_init(struct net *net)
3397{
3398 net->ipv4.sysctl_tcp_ecn = 2;
3399 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3400
3401 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3402 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3403 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3404 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3405 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3406
3407 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3408 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3409 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3410
3411 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3412 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3413 net->ipv4.sysctl_tcp_syncookies = 1;
3414 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3415 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3416 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3417 net->ipv4.sysctl_tcp_orphan_retries = 0;
3418 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3419 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3420 net->ipv4.sysctl_tcp_tw_reuse = 2;
3421 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3422
3423 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3424 tcp_set_hashinfo(net);
3425
3426 net->ipv4.sysctl_tcp_sack = 1;
3427 net->ipv4.sysctl_tcp_window_scaling = 1;
3428 net->ipv4.sysctl_tcp_timestamps = 1;
3429 net->ipv4.sysctl_tcp_early_retrans = 3;
3430 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3431 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3432 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3433 net->ipv4.sysctl_tcp_max_reordering = 300;
3434 net->ipv4.sysctl_tcp_dsack = 1;
3435 net->ipv4.sysctl_tcp_app_win = 31;
3436 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3437 net->ipv4.sysctl_tcp_frto = 2;
3438 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3439 /* This limits the percentage of the congestion window which we
3440 * will allow a single TSO frame to consume. Building TSO frames
3441 * which are too large can cause TCP streams to be bursty.
3442 */
3443 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3444 /* Default TSQ limit of 16 TSO segments */
3445 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3446
3447 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3448 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3449
3450 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3451 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3452 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3453 net->ipv4.sysctl_tcp_autocorking = 1;
3454 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3455 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3456 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3457 if (net != &init_net) {
3458 memcpy(net->ipv4.sysctl_tcp_rmem,
3459 init_net.ipv4.sysctl_tcp_rmem,
3460 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3461 memcpy(net->ipv4.sysctl_tcp_wmem,
3462 init_net.ipv4.sysctl_tcp_wmem,
3463 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3464 }
3465 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3466 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3467 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3468 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3469 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3470 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3471 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3472
3473 /* Set default values for PLB */
3474 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3475 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3476 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3477 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3478 /* Default congestion threshold for PLB to mark a round is 50% */
3479 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3480
3481 /* Reno is always built in */
3482 if (!net_eq(net, &init_net) &&
3483 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3484 init_net.ipv4.tcp_congestion_control->owner))
3485 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3486 else
3487 net->ipv4.tcp_congestion_control = &tcp_reno;
3488
3489 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3490 net->ipv4.sysctl_tcp_shrink_window = 0;
3491
3492 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3493
3494 return 0;
3495}
3496
3497static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3498{
3499 struct net *net;
3500
3501 tcp_twsk_purge(net_exit_list, AF_INET);
3502
3503 list_for_each_entry(net, net_exit_list, exit_list) {
3504 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3505 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3506 tcp_fastopen_ctx_destroy(net);
3507 }
3508}
3509
3510static struct pernet_operations __net_initdata tcp_sk_ops = {
3511 .init = tcp_sk_init,
3512 .exit = tcp_sk_exit,
3513 .exit_batch = tcp_sk_exit_batch,
3514};
3515
3516#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3517DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3518 struct sock_common *sk_common, uid_t uid)
3519
3520#define INIT_BATCH_SZ 16
3521
3522static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3523{
3524 struct bpf_tcp_iter_state *iter = priv_data;
3525 int err;
3526
3527 err = bpf_iter_init_seq_net(priv_data, aux);
3528 if (err)
3529 return err;
3530
3531 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3532 if (err) {
3533 bpf_iter_fini_seq_net(priv_data);
3534 return err;
3535 }
3536
3537 return 0;
3538}
3539
3540static void bpf_iter_fini_tcp(void *priv_data)
3541{
3542 struct bpf_tcp_iter_state *iter = priv_data;
3543
3544 bpf_iter_fini_seq_net(priv_data);
3545 kvfree(iter->batch);
3546}
3547
3548static const struct bpf_iter_seq_info tcp_seq_info = {
3549 .seq_ops = &bpf_iter_tcp_seq_ops,
3550 .init_seq_private = bpf_iter_init_tcp,
3551 .fini_seq_private = bpf_iter_fini_tcp,
3552 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3553};
3554
3555static const struct bpf_func_proto *
3556bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3557 const struct bpf_prog *prog)
3558{
3559 switch (func_id) {
3560 case BPF_FUNC_setsockopt:
3561 return &bpf_sk_setsockopt_proto;
3562 case BPF_FUNC_getsockopt:
3563 return &bpf_sk_getsockopt_proto;
3564 default:
3565 return NULL;
3566 }
3567}
3568
3569static struct bpf_iter_reg tcp_reg_info = {
3570 .target = "tcp",
3571 .ctx_arg_info_size = 1,
3572 .ctx_arg_info = {
3573 { offsetof(struct bpf_iter__tcp, sk_common),
3574 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3575 },
3576 .get_func_proto = bpf_iter_tcp_get_func_proto,
3577 .seq_info = &tcp_seq_info,
3578};
3579
3580static void __init bpf_iter_register(void)
3581{
3582 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3583 if (bpf_iter_reg_target(&tcp_reg_info))
3584 pr_warn("Warning: could not register bpf iterator tcp\n");
3585}
3586
3587#endif
3588
3589void __init tcp_v4_init(void)
3590{
3591 int cpu, res;
3592
3593 for_each_possible_cpu(cpu) {
3594 struct sock *sk;
3595
3596 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3597 IPPROTO_TCP, &init_net);
3598 if (res)
3599 panic("Failed to create the TCP control socket.\n");
3600 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3601
3602 /* Please enforce IP_DF and IPID==0 for RST and
3603 * ACK sent in SYN-RECV and TIME-WAIT state.
3604 */
3605 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3606
3607 per_cpu(ipv4_tcp_sk, cpu) = sk;
3608 }
3609 if (register_pernet_subsys(&tcp_sk_ops))
3610 panic("Failed to create the TCP control socket.\n");
3611
3612#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3613 bpf_iter_register();
3614#endif
3615}