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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
54#include <linux/bottom_half.h>
55#include <linux/types.h>
56#include <linux/fcntl.h>
57#include <linux/module.h>
58#include <linux/random.h>
59#include <linux/cache.h>
60#include <linux/jhash.h>
61#include <linux/init.h>
62#include <linux/times.h>
63#include <linux/slab.h>
64
65#include <net/net_namespace.h>
66#include <net/icmp.h>
67#include <net/inet_hashtables.h>
68#include <net/tcp.h>
69#include <net/transp_v6.h>
70#include <net/ipv6.h>
71#include <net/inet_common.h>
72#include <net/timewait_sock.h>
73#include <net/xfrm.h>
74#include <net/netdma.h>
75#include <net/secure_seq.h>
76
77#include <linux/inet.h>
78#include <linux/ipv6.h>
79#include <linux/stddef.h>
80#include <linux/proc_fs.h>
81#include <linux/seq_file.h>
82
83#include <linux/crypto.h>
84#include <linux/scatterlist.h>
85
86int sysctl_tcp_tw_reuse __read_mostly;
87int sysctl_tcp_low_latency __read_mostly;
88EXPORT_SYMBOL(sysctl_tcp_low_latency);
89
90
91#ifdef CONFIG_TCP_MD5SIG
92static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
93 __be32 addr);
94static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, struct tcphdr *th);
96#else
97static inline
98struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
99{
100 return NULL;
101}
102#endif
103
104struct inet_hashinfo tcp_hashinfo;
105EXPORT_SYMBOL(tcp_hashinfo);
106
107static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
108{
109 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
110 ip_hdr(skb)->saddr,
111 tcp_hdr(skb)->dest,
112 tcp_hdr(skb)->source);
113}
114
115int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
116{
117 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
118 struct tcp_sock *tp = tcp_sk(sk);
119
120 /* With PAWS, it is safe from the viewpoint
121 of data integrity. Even without PAWS it is safe provided sequence
122 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
123
124 Actually, the idea is close to VJ's one, only timestamp cache is
125 held not per host, but per port pair and TW bucket is used as state
126 holder.
127
128 If TW bucket has been already destroyed we fall back to VJ's scheme
129 and use initial timestamp retrieved from peer table.
130 */
131 if (tcptw->tw_ts_recent_stamp &&
132 (twp == NULL || (sysctl_tcp_tw_reuse &&
133 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
134 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
135 if (tp->write_seq == 0)
136 tp->write_seq = 1;
137 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
138 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
139 sock_hold(sktw);
140 return 1;
141 }
142
143 return 0;
144}
145EXPORT_SYMBOL_GPL(tcp_twsk_unique);
146
147/* This will initiate an outgoing connection. */
148int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
149{
150 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
151 struct inet_sock *inet = inet_sk(sk);
152 struct tcp_sock *tp = tcp_sk(sk);
153 __be16 orig_sport, orig_dport;
154 __be32 daddr, nexthop;
155 struct flowi4 *fl4;
156 struct rtable *rt;
157 int err;
158 struct ip_options_rcu *inet_opt;
159
160 if (addr_len < sizeof(struct sockaddr_in))
161 return -EINVAL;
162
163 if (usin->sin_family != AF_INET)
164 return -EAFNOSUPPORT;
165
166 nexthop = daddr = usin->sin_addr.s_addr;
167 inet_opt = rcu_dereference_protected(inet->inet_opt,
168 sock_owned_by_user(sk));
169 if (inet_opt && inet_opt->opt.srr) {
170 if (!daddr)
171 return -EINVAL;
172 nexthop = inet_opt->opt.faddr;
173 }
174
175 orig_sport = inet->inet_sport;
176 orig_dport = usin->sin_port;
177 fl4 = &inet->cork.fl.u.ip4;
178 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
179 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
180 IPPROTO_TCP,
181 orig_sport, orig_dport, sk, true);
182 if (IS_ERR(rt)) {
183 err = PTR_ERR(rt);
184 if (err == -ENETUNREACH)
185 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
186 return err;
187 }
188
189 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
190 ip_rt_put(rt);
191 return -ENETUNREACH;
192 }
193
194 if (!inet_opt || !inet_opt->opt.srr)
195 daddr = fl4->daddr;
196
197 if (!inet->inet_saddr)
198 inet->inet_saddr = fl4->saddr;
199 inet->inet_rcv_saddr = inet->inet_saddr;
200
201 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
202 /* Reset inherited state */
203 tp->rx_opt.ts_recent = 0;
204 tp->rx_opt.ts_recent_stamp = 0;
205 tp->write_seq = 0;
206 }
207
208 if (tcp_death_row.sysctl_tw_recycle &&
209 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
210 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
211 /*
212 * VJ's idea. We save last timestamp seen from
213 * the destination in peer table, when entering state
214 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
215 * when trying new connection.
216 */
217 if (peer) {
218 inet_peer_refcheck(peer);
219 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
220 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
221 tp->rx_opt.ts_recent = peer->tcp_ts;
222 }
223 }
224 }
225
226 inet->inet_dport = usin->sin_port;
227 inet->inet_daddr = daddr;
228
229 inet_csk(sk)->icsk_ext_hdr_len = 0;
230 if (inet_opt)
231 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
232
233 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
234
235 /* Socket identity is still unknown (sport may be zero).
236 * However we set state to SYN-SENT and not releasing socket
237 * lock select source port, enter ourselves into the hash tables and
238 * complete initialization after this.
239 */
240 tcp_set_state(sk, TCP_SYN_SENT);
241 err = inet_hash_connect(&tcp_death_row, sk);
242 if (err)
243 goto failure;
244
245 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
246 inet->inet_sport, inet->inet_dport, sk);
247 if (IS_ERR(rt)) {
248 err = PTR_ERR(rt);
249 rt = NULL;
250 goto failure;
251 }
252 /* OK, now commit destination to socket. */
253 sk->sk_gso_type = SKB_GSO_TCPV4;
254 sk_setup_caps(sk, &rt->dst);
255
256 if (!tp->write_seq)
257 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
258 inet->inet_daddr,
259 inet->inet_sport,
260 usin->sin_port);
261
262 inet->inet_id = tp->write_seq ^ jiffies;
263
264 err = tcp_connect(sk);
265 rt = NULL;
266 if (err)
267 goto failure;
268
269 return 0;
270
271failure:
272 /*
273 * This unhashes the socket and releases the local port,
274 * if necessary.
275 */
276 tcp_set_state(sk, TCP_CLOSE);
277 ip_rt_put(rt);
278 sk->sk_route_caps = 0;
279 inet->inet_dport = 0;
280 return err;
281}
282EXPORT_SYMBOL(tcp_v4_connect);
283
284/*
285 * This routine does path mtu discovery as defined in RFC1191.
286 */
287static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
288{
289 struct dst_entry *dst;
290 struct inet_sock *inet = inet_sk(sk);
291
292 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
293 * send out by Linux are always <576bytes so they should go through
294 * unfragmented).
295 */
296 if (sk->sk_state == TCP_LISTEN)
297 return;
298
299 /* We don't check in the destentry if pmtu discovery is forbidden
300 * on this route. We just assume that no packet_to_big packets
301 * are send back when pmtu discovery is not active.
302 * There is a small race when the user changes this flag in the
303 * route, but I think that's acceptable.
304 */
305 if ((dst = __sk_dst_check(sk, 0)) == NULL)
306 return;
307
308 dst->ops->update_pmtu(dst, mtu);
309
310 /* Something is about to be wrong... Remember soft error
311 * for the case, if this connection will not able to recover.
312 */
313 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
314 sk->sk_err_soft = EMSGSIZE;
315
316 mtu = dst_mtu(dst);
317
318 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
319 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
320 tcp_sync_mss(sk, mtu);
321
322 /* Resend the TCP packet because it's
323 * clear that the old packet has been
324 * dropped. This is the new "fast" path mtu
325 * discovery.
326 */
327 tcp_simple_retransmit(sk);
328 } /* else let the usual retransmit timer handle it */
329}
330
331/*
332 * This routine is called by the ICMP module when it gets some
333 * sort of error condition. If err < 0 then the socket should
334 * be closed and the error returned to the user. If err > 0
335 * it's just the icmp type << 8 | icmp code. After adjustment
336 * header points to the first 8 bytes of the tcp header. We need
337 * to find the appropriate port.
338 *
339 * The locking strategy used here is very "optimistic". When
340 * someone else accesses the socket the ICMP is just dropped
341 * and for some paths there is no check at all.
342 * A more general error queue to queue errors for later handling
343 * is probably better.
344 *
345 */
346
347void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
348{
349 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
350 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
351 struct inet_connection_sock *icsk;
352 struct tcp_sock *tp;
353 struct inet_sock *inet;
354 const int type = icmp_hdr(icmp_skb)->type;
355 const int code = icmp_hdr(icmp_skb)->code;
356 struct sock *sk;
357 struct sk_buff *skb;
358 __u32 seq;
359 __u32 remaining;
360 int err;
361 struct net *net = dev_net(icmp_skb->dev);
362
363 if (icmp_skb->len < (iph->ihl << 2) + 8) {
364 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
365 return;
366 }
367
368 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
369 iph->saddr, th->source, inet_iif(icmp_skb));
370 if (!sk) {
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
372 return;
373 }
374 if (sk->sk_state == TCP_TIME_WAIT) {
375 inet_twsk_put(inet_twsk(sk));
376 return;
377 }
378
379 bh_lock_sock(sk);
380 /* If too many ICMPs get dropped on busy
381 * servers this needs to be solved differently.
382 */
383 if (sock_owned_by_user(sk))
384 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
385
386 if (sk->sk_state == TCP_CLOSE)
387 goto out;
388
389 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
390 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
391 goto out;
392 }
393
394 icsk = inet_csk(sk);
395 tp = tcp_sk(sk);
396 seq = ntohl(th->seq);
397 if (sk->sk_state != TCP_LISTEN &&
398 !between(seq, tp->snd_una, tp->snd_nxt)) {
399 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
400 goto out;
401 }
402
403 switch (type) {
404 case ICMP_SOURCE_QUENCH:
405 /* Just silently ignore these. */
406 goto out;
407 case ICMP_PARAMETERPROB:
408 err = EPROTO;
409 break;
410 case ICMP_DEST_UNREACH:
411 if (code > NR_ICMP_UNREACH)
412 goto out;
413
414 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
415 if (!sock_owned_by_user(sk))
416 do_pmtu_discovery(sk, iph, info);
417 goto out;
418 }
419
420 err = icmp_err_convert[code].errno;
421 /* check if icmp_skb allows revert of backoff
422 * (see draft-zimmermann-tcp-lcd) */
423 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
424 break;
425 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
426 !icsk->icsk_backoff)
427 break;
428
429 if (sock_owned_by_user(sk))
430 break;
431
432 icsk->icsk_backoff--;
433 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
434 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
435 tcp_bound_rto(sk);
436
437 skb = tcp_write_queue_head(sk);
438 BUG_ON(!skb);
439
440 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
441 tcp_time_stamp - TCP_SKB_CB(skb)->when);
442
443 if (remaining) {
444 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
445 remaining, TCP_RTO_MAX);
446 } else {
447 /* RTO revert clocked out retransmission.
448 * Will retransmit now */
449 tcp_retransmit_timer(sk);
450 }
451
452 break;
453 case ICMP_TIME_EXCEEDED:
454 err = EHOSTUNREACH;
455 break;
456 default:
457 goto out;
458 }
459
460 switch (sk->sk_state) {
461 struct request_sock *req, **prev;
462 case TCP_LISTEN:
463 if (sock_owned_by_user(sk))
464 goto out;
465
466 req = inet_csk_search_req(sk, &prev, th->dest,
467 iph->daddr, iph->saddr);
468 if (!req)
469 goto out;
470
471 /* ICMPs are not backlogged, hence we cannot get
472 an established socket here.
473 */
474 WARN_ON(req->sk);
475
476 if (seq != tcp_rsk(req)->snt_isn) {
477 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
478 goto out;
479 }
480
481 /*
482 * Still in SYN_RECV, just remove it silently.
483 * There is no good way to pass the error to the newly
484 * created socket, and POSIX does not want network
485 * errors returned from accept().
486 */
487 inet_csk_reqsk_queue_drop(sk, req, prev);
488 goto out;
489
490 case TCP_SYN_SENT:
491 case TCP_SYN_RECV: /* Cannot happen.
492 It can f.e. if SYNs crossed.
493 */
494 if (!sock_owned_by_user(sk)) {
495 sk->sk_err = err;
496
497 sk->sk_error_report(sk);
498
499 tcp_done(sk);
500 } else {
501 sk->sk_err_soft = err;
502 }
503 goto out;
504 }
505
506 /* If we've already connected we will keep trying
507 * until we time out, or the user gives up.
508 *
509 * rfc1122 4.2.3.9 allows to consider as hard errors
510 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
511 * but it is obsoleted by pmtu discovery).
512 *
513 * Note, that in modern internet, where routing is unreliable
514 * and in each dark corner broken firewalls sit, sending random
515 * errors ordered by their masters even this two messages finally lose
516 * their original sense (even Linux sends invalid PORT_UNREACHs)
517 *
518 * Now we are in compliance with RFCs.
519 * --ANK (980905)
520 */
521
522 inet = inet_sk(sk);
523 if (!sock_owned_by_user(sk) && inet->recverr) {
524 sk->sk_err = err;
525 sk->sk_error_report(sk);
526 } else { /* Only an error on timeout */
527 sk->sk_err_soft = err;
528 }
529
530out:
531 bh_unlock_sock(sk);
532 sock_put(sk);
533}
534
535static void __tcp_v4_send_check(struct sk_buff *skb,
536 __be32 saddr, __be32 daddr)
537{
538 struct tcphdr *th = tcp_hdr(skb);
539
540 if (skb->ip_summed == CHECKSUM_PARTIAL) {
541 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
542 skb->csum_start = skb_transport_header(skb) - skb->head;
543 skb->csum_offset = offsetof(struct tcphdr, check);
544 } else {
545 th->check = tcp_v4_check(skb->len, saddr, daddr,
546 csum_partial(th,
547 th->doff << 2,
548 skb->csum));
549 }
550}
551
552/* This routine computes an IPv4 TCP checksum. */
553void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
554{
555 struct inet_sock *inet = inet_sk(sk);
556
557 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
558}
559EXPORT_SYMBOL(tcp_v4_send_check);
560
561int tcp_v4_gso_send_check(struct sk_buff *skb)
562{
563 const struct iphdr *iph;
564 struct tcphdr *th;
565
566 if (!pskb_may_pull(skb, sizeof(*th)))
567 return -EINVAL;
568
569 iph = ip_hdr(skb);
570 th = tcp_hdr(skb);
571
572 th->check = 0;
573 skb->ip_summed = CHECKSUM_PARTIAL;
574 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
575 return 0;
576}
577
578/*
579 * This routine will send an RST to the other tcp.
580 *
581 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
582 * for reset.
583 * Answer: if a packet caused RST, it is not for a socket
584 * existing in our system, if it is matched to a socket,
585 * it is just duplicate segment or bug in other side's TCP.
586 * So that we build reply only basing on parameters
587 * arrived with segment.
588 * Exception: precedence violation. We do not implement it in any case.
589 */
590
591static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
592{
593 struct tcphdr *th = tcp_hdr(skb);
594 struct {
595 struct tcphdr th;
596#ifdef CONFIG_TCP_MD5SIG
597 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
598#endif
599 } rep;
600 struct ip_reply_arg arg;
601#ifdef CONFIG_TCP_MD5SIG
602 struct tcp_md5sig_key *key;
603#endif
604 struct net *net;
605
606 /* Never send a reset in response to a reset. */
607 if (th->rst)
608 return;
609
610 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
611 return;
612
613 /* Swap the send and the receive. */
614 memset(&rep, 0, sizeof(rep));
615 rep.th.dest = th->source;
616 rep.th.source = th->dest;
617 rep.th.doff = sizeof(struct tcphdr) / 4;
618 rep.th.rst = 1;
619
620 if (th->ack) {
621 rep.th.seq = th->ack_seq;
622 } else {
623 rep.th.ack = 1;
624 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
625 skb->len - (th->doff << 2));
626 }
627
628 memset(&arg, 0, sizeof(arg));
629 arg.iov[0].iov_base = (unsigned char *)&rep;
630 arg.iov[0].iov_len = sizeof(rep.th);
631
632#ifdef CONFIG_TCP_MD5SIG
633 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
634 if (key) {
635 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
636 (TCPOPT_NOP << 16) |
637 (TCPOPT_MD5SIG << 8) |
638 TCPOLEN_MD5SIG);
639 /* Update length and the length the header thinks exists */
640 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
641 rep.th.doff = arg.iov[0].iov_len / 4;
642
643 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
644 key, ip_hdr(skb)->saddr,
645 ip_hdr(skb)->daddr, &rep.th);
646 }
647#endif
648 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
649 ip_hdr(skb)->saddr, /* XXX */
650 arg.iov[0].iov_len, IPPROTO_TCP, 0);
651 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
652 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
653
654 net = dev_net(skb_dst(skb)->dev);
655 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
656 &arg, arg.iov[0].iov_len);
657
658 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
659 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
660}
661
662/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
663 outside socket context is ugly, certainly. What can I do?
664 */
665
666static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
667 u32 win, u32 ts, int oif,
668 struct tcp_md5sig_key *key,
669 int reply_flags)
670{
671 struct tcphdr *th = tcp_hdr(skb);
672 struct {
673 struct tcphdr th;
674 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
675#ifdef CONFIG_TCP_MD5SIG
676 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
677#endif
678 ];
679 } rep;
680 struct ip_reply_arg arg;
681 struct net *net = dev_net(skb_dst(skb)->dev);
682
683 memset(&rep.th, 0, sizeof(struct tcphdr));
684 memset(&arg, 0, sizeof(arg));
685
686 arg.iov[0].iov_base = (unsigned char *)&rep;
687 arg.iov[0].iov_len = sizeof(rep.th);
688 if (ts) {
689 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
690 (TCPOPT_TIMESTAMP << 8) |
691 TCPOLEN_TIMESTAMP);
692 rep.opt[1] = htonl(tcp_time_stamp);
693 rep.opt[2] = htonl(ts);
694 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
695 }
696
697 /* Swap the send and the receive. */
698 rep.th.dest = th->source;
699 rep.th.source = th->dest;
700 rep.th.doff = arg.iov[0].iov_len / 4;
701 rep.th.seq = htonl(seq);
702 rep.th.ack_seq = htonl(ack);
703 rep.th.ack = 1;
704 rep.th.window = htons(win);
705
706#ifdef CONFIG_TCP_MD5SIG
707 if (key) {
708 int offset = (ts) ? 3 : 0;
709
710 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
711 (TCPOPT_NOP << 16) |
712 (TCPOPT_MD5SIG << 8) |
713 TCPOLEN_MD5SIG);
714 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
715 rep.th.doff = arg.iov[0].iov_len/4;
716
717 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
718 key, ip_hdr(skb)->saddr,
719 ip_hdr(skb)->daddr, &rep.th);
720 }
721#endif
722 arg.flags = reply_flags;
723 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
724 ip_hdr(skb)->saddr, /* XXX */
725 arg.iov[0].iov_len, IPPROTO_TCP, 0);
726 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
727 if (oif)
728 arg.bound_dev_if = oif;
729
730 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
731 &arg, arg.iov[0].iov_len);
732
733 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
734}
735
736static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
737{
738 struct inet_timewait_sock *tw = inet_twsk(sk);
739 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
740
741 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
742 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
743 tcptw->tw_ts_recent,
744 tw->tw_bound_dev_if,
745 tcp_twsk_md5_key(tcptw),
746 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
747 );
748
749 inet_twsk_put(tw);
750}
751
752static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
753 struct request_sock *req)
754{
755 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
756 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
757 req->ts_recent,
758 0,
759 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
760 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
761}
762
763/*
764 * Send a SYN-ACK after having received a SYN.
765 * This still operates on a request_sock only, not on a big
766 * socket.
767 */
768static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
769 struct request_sock *req,
770 struct request_values *rvp)
771{
772 const struct inet_request_sock *ireq = inet_rsk(req);
773 struct flowi4 fl4;
774 int err = -1;
775 struct sk_buff * skb;
776
777 /* First, grab a route. */
778 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
779 return -1;
780
781 skb = tcp_make_synack(sk, dst, req, rvp);
782
783 if (skb) {
784 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
785
786 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
787 ireq->rmt_addr,
788 ireq->opt);
789 err = net_xmit_eval(err);
790 }
791
792 dst_release(dst);
793 return err;
794}
795
796static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
797 struct request_values *rvp)
798{
799 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
800 return tcp_v4_send_synack(sk, NULL, req, rvp);
801}
802
803/*
804 * IPv4 request_sock destructor.
805 */
806static void tcp_v4_reqsk_destructor(struct request_sock *req)
807{
808 kfree(inet_rsk(req)->opt);
809}
810
811/*
812 * Return 1 if a syncookie should be sent
813 */
814int tcp_syn_flood_action(struct sock *sk,
815 const struct sk_buff *skb,
816 const char *proto)
817{
818 const char *msg = "Dropping request";
819 int want_cookie = 0;
820 struct listen_sock *lopt;
821
822
823
824#ifdef CONFIG_SYN_COOKIES
825 if (sysctl_tcp_syncookies) {
826 msg = "Sending cookies";
827 want_cookie = 1;
828 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
829 } else
830#endif
831 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
832
833 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
834 if (!lopt->synflood_warned) {
835 lopt->synflood_warned = 1;
836 pr_info("%s: Possible SYN flooding on port %d. %s. "
837 " Check SNMP counters.\n",
838 proto, ntohs(tcp_hdr(skb)->dest), msg);
839 }
840 return want_cookie;
841}
842EXPORT_SYMBOL(tcp_syn_flood_action);
843
844/*
845 * Save and compile IPv4 options into the request_sock if needed.
846 */
847static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
848 struct sk_buff *skb)
849{
850 const struct ip_options *opt = &(IPCB(skb)->opt);
851 struct ip_options_rcu *dopt = NULL;
852
853 if (opt && opt->optlen) {
854 int opt_size = sizeof(*dopt) + opt->optlen;
855
856 dopt = kmalloc(opt_size, GFP_ATOMIC);
857 if (dopt) {
858 if (ip_options_echo(&dopt->opt, skb)) {
859 kfree(dopt);
860 dopt = NULL;
861 }
862 }
863 }
864 return dopt;
865}
866
867#ifdef CONFIG_TCP_MD5SIG
868/*
869 * RFC2385 MD5 checksumming requires a mapping of
870 * IP address->MD5 Key.
871 * We need to maintain these in the sk structure.
872 */
873
874/* Find the Key structure for an address. */
875static struct tcp_md5sig_key *
876 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
877{
878 struct tcp_sock *tp = tcp_sk(sk);
879 int i;
880
881 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
882 return NULL;
883 for (i = 0; i < tp->md5sig_info->entries4; i++) {
884 if (tp->md5sig_info->keys4[i].addr == addr)
885 return &tp->md5sig_info->keys4[i].base;
886 }
887 return NULL;
888}
889
890struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
891 struct sock *addr_sk)
892{
893 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
894}
895EXPORT_SYMBOL(tcp_v4_md5_lookup);
896
897static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
898 struct request_sock *req)
899{
900 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
901}
902
903/* This can be called on a newly created socket, from other files */
904int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
905 u8 *newkey, u8 newkeylen)
906{
907 /* Add Key to the list */
908 struct tcp_md5sig_key *key;
909 struct tcp_sock *tp = tcp_sk(sk);
910 struct tcp4_md5sig_key *keys;
911
912 key = tcp_v4_md5_do_lookup(sk, addr);
913 if (key) {
914 /* Pre-existing entry - just update that one. */
915 kfree(key->key);
916 key->key = newkey;
917 key->keylen = newkeylen;
918 } else {
919 struct tcp_md5sig_info *md5sig;
920
921 if (!tp->md5sig_info) {
922 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
923 GFP_ATOMIC);
924 if (!tp->md5sig_info) {
925 kfree(newkey);
926 return -ENOMEM;
927 }
928 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
929 }
930
931 md5sig = tp->md5sig_info;
932 if (md5sig->entries4 == 0 &&
933 tcp_alloc_md5sig_pool(sk) == NULL) {
934 kfree(newkey);
935 return -ENOMEM;
936 }
937
938 if (md5sig->alloced4 == md5sig->entries4) {
939 keys = kmalloc((sizeof(*keys) *
940 (md5sig->entries4 + 1)), GFP_ATOMIC);
941 if (!keys) {
942 kfree(newkey);
943 if (md5sig->entries4 == 0)
944 tcp_free_md5sig_pool();
945 return -ENOMEM;
946 }
947
948 if (md5sig->entries4)
949 memcpy(keys, md5sig->keys4,
950 sizeof(*keys) * md5sig->entries4);
951
952 /* Free old key list, and reference new one */
953 kfree(md5sig->keys4);
954 md5sig->keys4 = keys;
955 md5sig->alloced4++;
956 }
957 md5sig->entries4++;
958 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
959 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
960 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
961 }
962 return 0;
963}
964EXPORT_SYMBOL(tcp_v4_md5_do_add);
965
966static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
967 u8 *newkey, u8 newkeylen)
968{
969 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
970 newkey, newkeylen);
971}
972
973int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
974{
975 struct tcp_sock *tp = tcp_sk(sk);
976 int i;
977
978 for (i = 0; i < tp->md5sig_info->entries4; i++) {
979 if (tp->md5sig_info->keys4[i].addr == addr) {
980 /* Free the key */
981 kfree(tp->md5sig_info->keys4[i].base.key);
982 tp->md5sig_info->entries4--;
983
984 if (tp->md5sig_info->entries4 == 0) {
985 kfree(tp->md5sig_info->keys4);
986 tp->md5sig_info->keys4 = NULL;
987 tp->md5sig_info->alloced4 = 0;
988 tcp_free_md5sig_pool();
989 } else if (tp->md5sig_info->entries4 != i) {
990 /* Need to do some manipulation */
991 memmove(&tp->md5sig_info->keys4[i],
992 &tp->md5sig_info->keys4[i+1],
993 (tp->md5sig_info->entries4 - i) *
994 sizeof(struct tcp4_md5sig_key));
995 }
996 return 0;
997 }
998 }
999 return -ENOENT;
1000}
1001EXPORT_SYMBOL(tcp_v4_md5_do_del);
1002
1003static void tcp_v4_clear_md5_list(struct sock *sk)
1004{
1005 struct tcp_sock *tp = tcp_sk(sk);
1006
1007 /* Free each key, then the set of key keys,
1008 * the crypto element, and then decrement our
1009 * hold on the last resort crypto.
1010 */
1011 if (tp->md5sig_info->entries4) {
1012 int i;
1013 for (i = 0; i < tp->md5sig_info->entries4; i++)
1014 kfree(tp->md5sig_info->keys4[i].base.key);
1015 tp->md5sig_info->entries4 = 0;
1016 tcp_free_md5sig_pool();
1017 }
1018 if (tp->md5sig_info->keys4) {
1019 kfree(tp->md5sig_info->keys4);
1020 tp->md5sig_info->keys4 = NULL;
1021 tp->md5sig_info->alloced4 = 0;
1022 }
1023}
1024
1025static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1026 int optlen)
1027{
1028 struct tcp_md5sig cmd;
1029 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1030 u8 *newkey;
1031
1032 if (optlen < sizeof(cmd))
1033 return -EINVAL;
1034
1035 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1036 return -EFAULT;
1037
1038 if (sin->sin_family != AF_INET)
1039 return -EINVAL;
1040
1041 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
1042 if (!tcp_sk(sk)->md5sig_info)
1043 return -ENOENT;
1044 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
1045 }
1046
1047 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1048 return -EINVAL;
1049
1050 if (!tcp_sk(sk)->md5sig_info) {
1051 struct tcp_sock *tp = tcp_sk(sk);
1052 struct tcp_md5sig_info *p;
1053
1054 p = kzalloc(sizeof(*p), sk->sk_allocation);
1055 if (!p)
1056 return -EINVAL;
1057
1058 tp->md5sig_info = p;
1059 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1060 }
1061
1062 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1063 if (!newkey)
1064 return -ENOMEM;
1065 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1066 newkey, cmd.tcpm_keylen);
1067}
1068
1069static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1070 __be32 daddr, __be32 saddr, int nbytes)
1071{
1072 struct tcp4_pseudohdr *bp;
1073 struct scatterlist sg;
1074
1075 bp = &hp->md5_blk.ip4;
1076
1077 /*
1078 * 1. the TCP pseudo-header (in the order: source IP address,
1079 * destination IP address, zero-padded protocol number, and
1080 * segment length)
1081 */
1082 bp->saddr = saddr;
1083 bp->daddr = daddr;
1084 bp->pad = 0;
1085 bp->protocol = IPPROTO_TCP;
1086 bp->len = cpu_to_be16(nbytes);
1087
1088 sg_init_one(&sg, bp, sizeof(*bp));
1089 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1090}
1091
1092static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1093 __be32 daddr, __be32 saddr, struct tcphdr *th)
1094{
1095 struct tcp_md5sig_pool *hp;
1096 struct hash_desc *desc;
1097
1098 hp = tcp_get_md5sig_pool();
1099 if (!hp)
1100 goto clear_hash_noput;
1101 desc = &hp->md5_desc;
1102
1103 if (crypto_hash_init(desc))
1104 goto clear_hash;
1105 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1106 goto clear_hash;
1107 if (tcp_md5_hash_header(hp, th))
1108 goto clear_hash;
1109 if (tcp_md5_hash_key(hp, key))
1110 goto clear_hash;
1111 if (crypto_hash_final(desc, md5_hash))
1112 goto clear_hash;
1113
1114 tcp_put_md5sig_pool();
1115 return 0;
1116
1117clear_hash:
1118 tcp_put_md5sig_pool();
1119clear_hash_noput:
1120 memset(md5_hash, 0, 16);
1121 return 1;
1122}
1123
1124int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1125 struct sock *sk, struct request_sock *req,
1126 struct sk_buff *skb)
1127{
1128 struct tcp_md5sig_pool *hp;
1129 struct hash_desc *desc;
1130 struct tcphdr *th = tcp_hdr(skb);
1131 __be32 saddr, daddr;
1132
1133 if (sk) {
1134 saddr = inet_sk(sk)->inet_saddr;
1135 daddr = inet_sk(sk)->inet_daddr;
1136 } else if (req) {
1137 saddr = inet_rsk(req)->loc_addr;
1138 daddr = inet_rsk(req)->rmt_addr;
1139 } else {
1140 const struct iphdr *iph = ip_hdr(skb);
1141 saddr = iph->saddr;
1142 daddr = iph->daddr;
1143 }
1144
1145 hp = tcp_get_md5sig_pool();
1146 if (!hp)
1147 goto clear_hash_noput;
1148 desc = &hp->md5_desc;
1149
1150 if (crypto_hash_init(desc))
1151 goto clear_hash;
1152
1153 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1154 goto clear_hash;
1155 if (tcp_md5_hash_header(hp, th))
1156 goto clear_hash;
1157 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1158 goto clear_hash;
1159 if (tcp_md5_hash_key(hp, key))
1160 goto clear_hash;
1161 if (crypto_hash_final(desc, md5_hash))
1162 goto clear_hash;
1163
1164 tcp_put_md5sig_pool();
1165 return 0;
1166
1167clear_hash:
1168 tcp_put_md5sig_pool();
1169clear_hash_noput:
1170 memset(md5_hash, 0, 16);
1171 return 1;
1172}
1173EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1174
1175static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1176{
1177 /*
1178 * This gets called for each TCP segment that arrives
1179 * so we want to be efficient.
1180 * We have 3 drop cases:
1181 * o No MD5 hash and one expected.
1182 * o MD5 hash and we're not expecting one.
1183 * o MD5 hash and its wrong.
1184 */
1185 __u8 *hash_location = NULL;
1186 struct tcp_md5sig_key *hash_expected;
1187 const struct iphdr *iph = ip_hdr(skb);
1188 struct tcphdr *th = tcp_hdr(skb);
1189 int genhash;
1190 unsigned char newhash[16];
1191
1192 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1193 hash_location = tcp_parse_md5sig_option(th);
1194
1195 /* We've parsed the options - do we have a hash? */
1196 if (!hash_expected && !hash_location)
1197 return 0;
1198
1199 if (hash_expected && !hash_location) {
1200 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1201 return 1;
1202 }
1203
1204 if (!hash_expected && hash_location) {
1205 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1206 return 1;
1207 }
1208
1209 /* Okay, so this is hash_expected and hash_location -
1210 * so we need to calculate the checksum.
1211 */
1212 genhash = tcp_v4_md5_hash_skb(newhash,
1213 hash_expected,
1214 NULL, NULL, skb);
1215
1216 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1217 if (net_ratelimit()) {
1218 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1219 &iph->saddr, ntohs(th->source),
1220 &iph->daddr, ntohs(th->dest),
1221 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1222 }
1223 return 1;
1224 }
1225 return 0;
1226}
1227
1228#endif
1229
1230struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1231 .family = PF_INET,
1232 .obj_size = sizeof(struct tcp_request_sock),
1233 .rtx_syn_ack = tcp_v4_rtx_synack,
1234 .send_ack = tcp_v4_reqsk_send_ack,
1235 .destructor = tcp_v4_reqsk_destructor,
1236 .send_reset = tcp_v4_send_reset,
1237 .syn_ack_timeout = tcp_syn_ack_timeout,
1238};
1239
1240#ifdef CONFIG_TCP_MD5SIG
1241static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1242 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1243 .calc_md5_hash = tcp_v4_md5_hash_skb,
1244};
1245#endif
1246
1247int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1248{
1249 struct tcp_extend_values tmp_ext;
1250 struct tcp_options_received tmp_opt;
1251 u8 *hash_location;
1252 struct request_sock *req;
1253 struct inet_request_sock *ireq;
1254 struct tcp_sock *tp = tcp_sk(sk);
1255 struct dst_entry *dst = NULL;
1256 __be32 saddr = ip_hdr(skb)->saddr;
1257 __be32 daddr = ip_hdr(skb)->daddr;
1258 __u32 isn = TCP_SKB_CB(skb)->when;
1259 int want_cookie = 0;
1260
1261 /* Never answer to SYNs send to broadcast or multicast */
1262 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1263 goto drop;
1264
1265 /* TW buckets are converted to open requests without
1266 * limitations, they conserve resources and peer is
1267 * evidently real one.
1268 */
1269 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1270 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1271 if (!want_cookie)
1272 goto drop;
1273 }
1274
1275 /* Accept backlog is full. If we have already queued enough
1276 * of warm entries in syn queue, drop request. It is better than
1277 * clogging syn queue with openreqs with exponentially increasing
1278 * timeout.
1279 */
1280 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1281 goto drop;
1282
1283 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1284 if (!req)
1285 goto drop;
1286
1287#ifdef CONFIG_TCP_MD5SIG
1288 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1289#endif
1290
1291 tcp_clear_options(&tmp_opt);
1292 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1293 tmp_opt.user_mss = tp->rx_opt.user_mss;
1294 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1295
1296 if (tmp_opt.cookie_plus > 0 &&
1297 tmp_opt.saw_tstamp &&
1298 !tp->rx_opt.cookie_out_never &&
1299 (sysctl_tcp_cookie_size > 0 ||
1300 (tp->cookie_values != NULL &&
1301 tp->cookie_values->cookie_desired > 0))) {
1302 u8 *c;
1303 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1304 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1305
1306 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1307 goto drop_and_release;
1308
1309 /* Secret recipe starts with IP addresses */
1310 *mess++ ^= (__force u32)daddr;
1311 *mess++ ^= (__force u32)saddr;
1312
1313 /* plus variable length Initiator Cookie */
1314 c = (u8 *)mess;
1315 while (l-- > 0)
1316 *c++ ^= *hash_location++;
1317
1318 want_cookie = 0; /* not our kind of cookie */
1319 tmp_ext.cookie_out_never = 0; /* false */
1320 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1321 } else if (!tp->rx_opt.cookie_in_always) {
1322 /* redundant indications, but ensure initialization. */
1323 tmp_ext.cookie_out_never = 1; /* true */
1324 tmp_ext.cookie_plus = 0;
1325 } else {
1326 goto drop_and_release;
1327 }
1328 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1329
1330 if (want_cookie && !tmp_opt.saw_tstamp)
1331 tcp_clear_options(&tmp_opt);
1332
1333 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1334 tcp_openreq_init(req, &tmp_opt, skb);
1335
1336 ireq = inet_rsk(req);
1337 ireq->loc_addr = daddr;
1338 ireq->rmt_addr = saddr;
1339 ireq->no_srccheck = inet_sk(sk)->transparent;
1340 ireq->opt = tcp_v4_save_options(sk, skb);
1341
1342 if (security_inet_conn_request(sk, skb, req))
1343 goto drop_and_free;
1344
1345 if (!want_cookie || tmp_opt.tstamp_ok)
1346 TCP_ECN_create_request(req, tcp_hdr(skb));
1347
1348 if (want_cookie) {
1349 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1350 req->cookie_ts = tmp_opt.tstamp_ok;
1351 } else if (!isn) {
1352 struct inet_peer *peer = NULL;
1353 struct flowi4 fl4;
1354
1355 /* VJ's idea. We save last timestamp seen
1356 * from the destination in peer table, when entering
1357 * state TIME-WAIT, and check against it before
1358 * accepting new connection request.
1359 *
1360 * If "isn" is not zero, this request hit alive
1361 * timewait bucket, so that all the necessary checks
1362 * are made in the function processing timewait state.
1363 */
1364 if (tmp_opt.saw_tstamp &&
1365 tcp_death_row.sysctl_tw_recycle &&
1366 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1367 fl4.daddr == saddr &&
1368 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1369 inet_peer_refcheck(peer);
1370 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1371 (s32)(peer->tcp_ts - req->ts_recent) >
1372 TCP_PAWS_WINDOW) {
1373 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1374 goto drop_and_release;
1375 }
1376 }
1377 /* Kill the following clause, if you dislike this way. */
1378 else if (!sysctl_tcp_syncookies &&
1379 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1380 (sysctl_max_syn_backlog >> 2)) &&
1381 (!peer || !peer->tcp_ts_stamp) &&
1382 (!dst || !dst_metric(dst, RTAX_RTT))) {
1383 /* Without syncookies last quarter of
1384 * backlog is filled with destinations,
1385 * proven to be alive.
1386 * It means that we continue to communicate
1387 * to destinations, already remembered
1388 * to the moment of synflood.
1389 */
1390 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1391 &saddr, ntohs(tcp_hdr(skb)->source));
1392 goto drop_and_release;
1393 }
1394
1395 isn = tcp_v4_init_sequence(skb);
1396 }
1397 tcp_rsk(req)->snt_isn = isn;
1398 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1399
1400 if (tcp_v4_send_synack(sk, dst, req,
1401 (struct request_values *)&tmp_ext) ||
1402 want_cookie)
1403 goto drop_and_free;
1404
1405 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1406 return 0;
1407
1408drop_and_release:
1409 dst_release(dst);
1410drop_and_free:
1411 reqsk_free(req);
1412drop:
1413 return 0;
1414}
1415EXPORT_SYMBOL(tcp_v4_conn_request);
1416
1417
1418/*
1419 * The three way handshake has completed - we got a valid synack -
1420 * now create the new socket.
1421 */
1422struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1423 struct request_sock *req,
1424 struct dst_entry *dst)
1425{
1426 struct inet_request_sock *ireq;
1427 struct inet_sock *newinet;
1428 struct tcp_sock *newtp;
1429 struct sock *newsk;
1430#ifdef CONFIG_TCP_MD5SIG
1431 struct tcp_md5sig_key *key;
1432#endif
1433 struct ip_options_rcu *inet_opt;
1434
1435 if (sk_acceptq_is_full(sk))
1436 goto exit_overflow;
1437
1438 newsk = tcp_create_openreq_child(sk, req, skb);
1439 if (!newsk)
1440 goto exit_nonewsk;
1441
1442 newsk->sk_gso_type = SKB_GSO_TCPV4;
1443
1444 newtp = tcp_sk(newsk);
1445 newinet = inet_sk(newsk);
1446 ireq = inet_rsk(req);
1447 newinet->inet_daddr = ireq->rmt_addr;
1448 newinet->inet_rcv_saddr = ireq->loc_addr;
1449 newinet->inet_saddr = ireq->loc_addr;
1450 inet_opt = ireq->opt;
1451 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1452 ireq->opt = NULL;
1453 newinet->mc_index = inet_iif(skb);
1454 newinet->mc_ttl = ip_hdr(skb)->ttl;
1455 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1456 if (inet_opt)
1457 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1458 newinet->inet_id = newtp->write_seq ^ jiffies;
1459
1460 if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
1461 goto put_and_exit;
1462
1463 sk_setup_caps(newsk, dst);
1464
1465 tcp_mtup_init(newsk);
1466 tcp_sync_mss(newsk, dst_mtu(dst));
1467 newtp->advmss = dst_metric_advmss(dst);
1468 if (tcp_sk(sk)->rx_opt.user_mss &&
1469 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1470 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1471
1472 tcp_initialize_rcv_mss(newsk);
1473 if (tcp_rsk(req)->snt_synack)
1474 tcp_valid_rtt_meas(newsk,
1475 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1476 newtp->total_retrans = req->retrans;
1477
1478#ifdef CONFIG_TCP_MD5SIG
1479 /* Copy over the MD5 key from the original socket */
1480 key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
1481 if (key != NULL) {
1482 /*
1483 * We're using one, so create a matching key
1484 * on the newsk structure. If we fail to get
1485 * memory, then we end up not copying the key
1486 * across. Shucks.
1487 */
1488 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1489 if (newkey != NULL)
1490 tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1491 newkey, key->keylen);
1492 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1493 }
1494#endif
1495
1496 if (__inet_inherit_port(sk, newsk) < 0)
1497 goto put_and_exit;
1498 __inet_hash_nolisten(newsk, NULL);
1499
1500 return newsk;
1501
1502exit_overflow:
1503 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1504exit_nonewsk:
1505 dst_release(dst);
1506exit:
1507 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1508 return NULL;
1509put_and_exit:
1510 sock_put(newsk);
1511 goto exit;
1512}
1513EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1514
1515static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1516{
1517 struct tcphdr *th = tcp_hdr(skb);
1518 const struct iphdr *iph = ip_hdr(skb);
1519 struct sock *nsk;
1520 struct request_sock **prev;
1521 /* Find possible connection requests. */
1522 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1523 iph->saddr, iph->daddr);
1524 if (req)
1525 return tcp_check_req(sk, skb, req, prev);
1526
1527 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1528 th->source, iph->daddr, th->dest, inet_iif(skb));
1529
1530 if (nsk) {
1531 if (nsk->sk_state != TCP_TIME_WAIT) {
1532 bh_lock_sock(nsk);
1533 return nsk;
1534 }
1535 inet_twsk_put(inet_twsk(nsk));
1536 return NULL;
1537 }
1538
1539#ifdef CONFIG_SYN_COOKIES
1540 if (!th->syn)
1541 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1542#endif
1543 return sk;
1544}
1545
1546static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1547{
1548 const struct iphdr *iph = ip_hdr(skb);
1549
1550 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1551 if (!tcp_v4_check(skb->len, iph->saddr,
1552 iph->daddr, skb->csum)) {
1553 skb->ip_summed = CHECKSUM_UNNECESSARY;
1554 return 0;
1555 }
1556 }
1557
1558 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1559 skb->len, IPPROTO_TCP, 0);
1560
1561 if (skb->len <= 76) {
1562 return __skb_checksum_complete(skb);
1563 }
1564 return 0;
1565}
1566
1567
1568/* The socket must have it's spinlock held when we get
1569 * here.
1570 *
1571 * We have a potential double-lock case here, so even when
1572 * doing backlog processing we use the BH locking scheme.
1573 * This is because we cannot sleep with the original spinlock
1574 * held.
1575 */
1576int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1577{
1578 struct sock *rsk;
1579#ifdef CONFIG_TCP_MD5SIG
1580 /*
1581 * We really want to reject the packet as early as possible
1582 * if:
1583 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1584 * o There is an MD5 option and we're not expecting one
1585 */
1586 if (tcp_v4_inbound_md5_hash(sk, skb))
1587 goto discard;
1588#endif
1589
1590 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1591 sock_rps_save_rxhash(sk, skb->rxhash);
1592 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1593 rsk = sk;
1594 goto reset;
1595 }
1596 return 0;
1597 }
1598
1599 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1600 goto csum_err;
1601
1602 if (sk->sk_state == TCP_LISTEN) {
1603 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1604 if (!nsk)
1605 goto discard;
1606
1607 if (nsk != sk) {
1608 sock_rps_save_rxhash(nsk, skb->rxhash);
1609 if (tcp_child_process(sk, nsk, skb)) {
1610 rsk = nsk;
1611 goto reset;
1612 }
1613 return 0;
1614 }
1615 } else
1616 sock_rps_save_rxhash(sk, skb->rxhash);
1617
1618 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1619 rsk = sk;
1620 goto reset;
1621 }
1622 return 0;
1623
1624reset:
1625 tcp_v4_send_reset(rsk, skb);
1626discard:
1627 kfree_skb(skb);
1628 /* Be careful here. If this function gets more complicated and
1629 * gcc suffers from register pressure on the x86, sk (in %ebx)
1630 * might be destroyed here. This current version compiles correctly,
1631 * but you have been warned.
1632 */
1633 return 0;
1634
1635csum_err:
1636 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1637 goto discard;
1638}
1639EXPORT_SYMBOL(tcp_v4_do_rcv);
1640
1641/*
1642 * From tcp_input.c
1643 */
1644
1645int tcp_v4_rcv(struct sk_buff *skb)
1646{
1647 const struct iphdr *iph;
1648 struct tcphdr *th;
1649 struct sock *sk;
1650 int ret;
1651 struct net *net = dev_net(skb->dev);
1652
1653 if (skb->pkt_type != PACKET_HOST)
1654 goto discard_it;
1655
1656 /* Count it even if it's bad */
1657 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1658
1659 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1660 goto discard_it;
1661
1662 th = tcp_hdr(skb);
1663
1664 if (th->doff < sizeof(struct tcphdr) / 4)
1665 goto bad_packet;
1666 if (!pskb_may_pull(skb, th->doff * 4))
1667 goto discard_it;
1668
1669 /* An explanation is required here, I think.
1670 * Packet length and doff are validated by header prediction,
1671 * provided case of th->doff==0 is eliminated.
1672 * So, we defer the checks. */
1673 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1674 goto bad_packet;
1675
1676 th = tcp_hdr(skb);
1677 iph = ip_hdr(skb);
1678 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1679 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1680 skb->len - th->doff * 4);
1681 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1682 TCP_SKB_CB(skb)->when = 0;
1683 TCP_SKB_CB(skb)->flags = iph->tos;
1684 TCP_SKB_CB(skb)->sacked = 0;
1685
1686 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1687 if (!sk)
1688 goto no_tcp_socket;
1689
1690process:
1691 if (sk->sk_state == TCP_TIME_WAIT)
1692 goto do_time_wait;
1693
1694 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1695 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1696 goto discard_and_relse;
1697 }
1698
1699 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1700 goto discard_and_relse;
1701 nf_reset(skb);
1702
1703 if (sk_filter(sk, skb))
1704 goto discard_and_relse;
1705
1706 skb->dev = NULL;
1707
1708 bh_lock_sock_nested(sk);
1709 ret = 0;
1710 if (!sock_owned_by_user(sk)) {
1711#ifdef CONFIG_NET_DMA
1712 struct tcp_sock *tp = tcp_sk(sk);
1713 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1714 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1715 if (tp->ucopy.dma_chan)
1716 ret = tcp_v4_do_rcv(sk, skb);
1717 else
1718#endif
1719 {
1720 if (!tcp_prequeue(sk, skb))
1721 ret = tcp_v4_do_rcv(sk, skb);
1722 }
1723 } else if (unlikely(sk_add_backlog(sk, skb))) {
1724 bh_unlock_sock(sk);
1725 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1726 goto discard_and_relse;
1727 }
1728 bh_unlock_sock(sk);
1729
1730 sock_put(sk);
1731
1732 return ret;
1733
1734no_tcp_socket:
1735 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1736 goto discard_it;
1737
1738 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1739bad_packet:
1740 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1741 } else {
1742 tcp_v4_send_reset(NULL, skb);
1743 }
1744
1745discard_it:
1746 /* Discard frame. */
1747 kfree_skb(skb);
1748 return 0;
1749
1750discard_and_relse:
1751 sock_put(sk);
1752 goto discard_it;
1753
1754do_time_wait:
1755 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1756 inet_twsk_put(inet_twsk(sk));
1757 goto discard_it;
1758 }
1759
1760 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1761 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1762 inet_twsk_put(inet_twsk(sk));
1763 goto discard_it;
1764 }
1765 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1766 case TCP_TW_SYN: {
1767 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1768 &tcp_hashinfo,
1769 iph->daddr, th->dest,
1770 inet_iif(skb));
1771 if (sk2) {
1772 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1773 inet_twsk_put(inet_twsk(sk));
1774 sk = sk2;
1775 goto process;
1776 }
1777 /* Fall through to ACK */
1778 }
1779 case TCP_TW_ACK:
1780 tcp_v4_timewait_ack(sk, skb);
1781 break;
1782 case TCP_TW_RST:
1783 goto no_tcp_socket;
1784 case TCP_TW_SUCCESS:;
1785 }
1786 goto discard_it;
1787}
1788
1789struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1790{
1791 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1792 struct inet_sock *inet = inet_sk(sk);
1793 struct inet_peer *peer;
1794
1795 if (!rt ||
1796 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1797 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1798 *release_it = true;
1799 } else {
1800 if (!rt->peer)
1801 rt_bind_peer(rt, inet->inet_daddr, 1);
1802 peer = rt->peer;
1803 *release_it = false;
1804 }
1805
1806 return peer;
1807}
1808EXPORT_SYMBOL(tcp_v4_get_peer);
1809
1810void *tcp_v4_tw_get_peer(struct sock *sk)
1811{
1812 struct inet_timewait_sock *tw = inet_twsk(sk);
1813
1814 return inet_getpeer_v4(tw->tw_daddr, 1);
1815}
1816EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1817
1818static struct timewait_sock_ops tcp_timewait_sock_ops = {
1819 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1820 .twsk_unique = tcp_twsk_unique,
1821 .twsk_destructor= tcp_twsk_destructor,
1822 .twsk_getpeer = tcp_v4_tw_get_peer,
1823};
1824
1825const struct inet_connection_sock_af_ops ipv4_specific = {
1826 .queue_xmit = ip_queue_xmit,
1827 .send_check = tcp_v4_send_check,
1828 .rebuild_header = inet_sk_rebuild_header,
1829 .conn_request = tcp_v4_conn_request,
1830 .syn_recv_sock = tcp_v4_syn_recv_sock,
1831 .get_peer = tcp_v4_get_peer,
1832 .net_header_len = sizeof(struct iphdr),
1833 .setsockopt = ip_setsockopt,
1834 .getsockopt = ip_getsockopt,
1835 .addr2sockaddr = inet_csk_addr2sockaddr,
1836 .sockaddr_len = sizeof(struct sockaddr_in),
1837 .bind_conflict = inet_csk_bind_conflict,
1838#ifdef CONFIG_COMPAT
1839 .compat_setsockopt = compat_ip_setsockopt,
1840 .compat_getsockopt = compat_ip_getsockopt,
1841#endif
1842};
1843EXPORT_SYMBOL(ipv4_specific);
1844
1845#ifdef CONFIG_TCP_MD5SIG
1846static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1847 .md5_lookup = tcp_v4_md5_lookup,
1848 .calc_md5_hash = tcp_v4_md5_hash_skb,
1849 .md5_add = tcp_v4_md5_add_func,
1850 .md5_parse = tcp_v4_parse_md5_keys,
1851};
1852#endif
1853
1854/* NOTE: A lot of things set to zero explicitly by call to
1855 * sk_alloc() so need not be done here.
1856 */
1857static int tcp_v4_init_sock(struct sock *sk)
1858{
1859 struct inet_connection_sock *icsk = inet_csk(sk);
1860 struct tcp_sock *tp = tcp_sk(sk);
1861
1862 skb_queue_head_init(&tp->out_of_order_queue);
1863 tcp_init_xmit_timers(sk);
1864 tcp_prequeue_init(tp);
1865
1866 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1867 tp->mdev = TCP_TIMEOUT_INIT;
1868
1869 /* So many TCP implementations out there (incorrectly) count the
1870 * initial SYN frame in their delayed-ACK and congestion control
1871 * algorithms that we must have the following bandaid to talk
1872 * efficiently to them. -DaveM
1873 */
1874 tp->snd_cwnd = TCP_INIT_CWND;
1875
1876 /* See draft-stevens-tcpca-spec-01 for discussion of the
1877 * initialization of these values.
1878 */
1879 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1880 tp->snd_cwnd_clamp = ~0;
1881 tp->mss_cache = TCP_MSS_DEFAULT;
1882
1883 tp->reordering = sysctl_tcp_reordering;
1884 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1885
1886 sk->sk_state = TCP_CLOSE;
1887
1888 sk->sk_write_space = sk_stream_write_space;
1889 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1890
1891 icsk->icsk_af_ops = &ipv4_specific;
1892 icsk->icsk_sync_mss = tcp_sync_mss;
1893#ifdef CONFIG_TCP_MD5SIG
1894 tp->af_specific = &tcp_sock_ipv4_specific;
1895#endif
1896
1897 /* TCP Cookie Transactions */
1898 if (sysctl_tcp_cookie_size > 0) {
1899 /* Default, cookies without s_data_payload. */
1900 tp->cookie_values =
1901 kzalloc(sizeof(*tp->cookie_values),
1902 sk->sk_allocation);
1903 if (tp->cookie_values != NULL)
1904 kref_init(&tp->cookie_values->kref);
1905 }
1906 /* Presumed zeroed, in order of appearance:
1907 * cookie_in_always, cookie_out_never,
1908 * s_data_constant, s_data_in, s_data_out
1909 */
1910 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1911 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1912
1913 local_bh_disable();
1914 percpu_counter_inc(&tcp_sockets_allocated);
1915 local_bh_enable();
1916
1917 return 0;
1918}
1919
1920void tcp_v4_destroy_sock(struct sock *sk)
1921{
1922 struct tcp_sock *tp = tcp_sk(sk);
1923
1924 tcp_clear_xmit_timers(sk);
1925
1926 tcp_cleanup_congestion_control(sk);
1927
1928 /* Cleanup up the write buffer. */
1929 tcp_write_queue_purge(sk);
1930
1931 /* Cleans up our, hopefully empty, out_of_order_queue. */
1932 __skb_queue_purge(&tp->out_of_order_queue);
1933
1934#ifdef CONFIG_TCP_MD5SIG
1935 /* Clean up the MD5 key list, if any */
1936 if (tp->md5sig_info) {
1937 tcp_v4_clear_md5_list(sk);
1938 kfree(tp->md5sig_info);
1939 tp->md5sig_info = NULL;
1940 }
1941#endif
1942
1943#ifdef CONFIG_NET_DMA
1944 /* Cleans up our sk_async_wait_queue */
1945 __skb_queue_purge(&sk->sk_async_wait_queue);
1946#endif
1947
1948 /* Clean prequeue, it must be empty really */
1949 __skb_queue_purge(&tp->ucopy.prequeue);
1950
1951 /* Clean up a referenced TCP bind bucket. */
1952 if (inet_csk(sk)->icsk_bind_hash)
1953 inet_put_port(sk);
1954
1955 /*
1956 * If sendmsg cached page exists, toss it.
1957 */
1958 if (sk->sk_sndmsg_page) {
1959 __free_page(sk->sk_sndmsg_page);
1960 sk->sk_sndmsg_page = NULL;
1961 }
1962
1963 /* TCP Cookie Transactions */
1964 if (tp->cookie_values != NULL) {
1965 kref_put(&tp->cookie_values->kref,
1966 tcp_cookie_values_release);
1967 tp->cookie_values = NULL;
1968 }
1969
1970 percpu_counter_dec(&tcp_sockets_allocated);
1971}
1972EXPORT_SYMBOL(tcp_v4_destroy_sock);
1973
1974#ifdef CONFIG_PROC_FS
1975/* Proc filesystem TCP sock list dumping. */
1976
1977static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1978{
1979 return hlist_nulls_empty(head) ? NULL :
1980 list_entry(head->first, struct inet_timewait_sock, tw_node);
1981}
1982
1983static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1984{
1985 return !is_a_nulls(tw->tw_node.next) ?
1986 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1987}
1988
1989/*
1990 * Get next listener socket follow cur. If cur is NULL, get first socket
1991 * starting from bucket given in st->bucket; when st->bucket is zero the
1992 * very first socket in the hash table is returned.
1993 */
1994static void *listening_get_next(struct seq_file *seq, void *cur)
1995{
1996 struct inet_connection_sock *icsk;
1997 struct hlist_nulls_node *node;
1998 struct sock *sk = cur;
1999 struct inet_listen_hashbucket *ilb;
2000 struct tcp_iter_state *st = seq->private;
2001 struct net *net = seq_file_net(seq);
2002
2003 if (!sk) {
2004 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2005 spin_lock_bh(&ilb->lock);
2006 sk = sk_nulls_head(&ilb->head);
2007 st->offset = 0;
2008 goto get_sk;
2009 }
2010 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2011 ++st->num;
2012 ++st->offset;
2013
2014 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2015 struct request_sock *req = cur;
2016
2017 icsk = inet_csk(st->syn_wait_sk);
2018 req = req->dl_next;
2019 while (1) {
2020 while (req) {
2021 if (req->rsk_ops->family == st->family) {
2022 cur = req;
2023 goto out;
2024 }
2025 req = req->dl_next;
2026 }
2027 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2028 break;
2029get_req:
2030 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2031 }
2032 sk = sk_nulls_next(st->syn_wait_sk);
2033 st->state = TCP_SEQ_STATE_LISTENING;
2034 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2035 } else {
2036 icsk = inet_csk(sk);
2037 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2038 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2039 goto start_req;
2040 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2041 sk = sk_nulls_next(sk);
2042 }
2043get_sk:
2044 sk_nulls_for_each_from(sk, node) {
2045 if (!net_eq(sock_net(sk), net))
2046 continue;
2047 if (sk->sk_family == st->family) {
2048 cur = sk;
2049 goto out;
2050 }
2051 icsk = inet_csk(sk);
2052 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2053 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2054start_req:
2055 st->uid = sock_i_uid(sk);
2056 st->syn_wait_sk = sk;
2057 st->state = TCP_SEQ_STATE_OPENREQ;
2058 st->sbucket = 0;
2059 goto get_req;
2060 }
2061 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2062 }
2063 spin_unlock_bh(&ilb->lock);
2064 st->offset = 0;
2065 if (++st->bucket < INET_LHTABLE_SIZE) {
2066 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2067 spin_lock_bh(&ilb->lock);
2068 sk = sk_nulls_head(&ilb->head);
2069 goto get_sk;
2070 }
2071 cur = NULL;
2072out:
2073 return cur;
2074}
2075
2076static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2077{
2078 struct tcp_iter_state *st = seq->private;
2079 void *rc;
2080
2081 st->bucket = 0;
2082 st->offset = 0;
2083 rc = listening_get_next(seq, NULL);
2084
2085 while (rc && *pos) {
2086 rc = listening_get_next(seq, rc);
2087 --*pos;
2088 }
2089 return rc;
2090}
2091
2092static inline int empty_bucket(struct tcp_iter_state *st)
2093{
2094 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2095 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2096}
2097
2098/*
2099 * Get first established socket starting from bucket given in st->bucket.
2100 * If st->bucket is zero, the very first socket in the hash is returned.
2101 */
2102static void *established_get_first(struct seq_file *seq)
2103{
2104 struct tcp_iter_state *st = seq->private;
2105 struct net *net = seq_file_net(seq);
2106 void *rc = NULL;
2107
2108 st->offset = 0;
2109 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2110 struct sock *sk;
2111 struct hlist_nulls_node *node;
2112 struct inet_timewait_sock *tw;
2113 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2114
2115 /* Lockless fast path for the common case of empty buckets */
2116 if (empty_bucket(st))
2117 continue;
2118
2119 spin_lock_bh(lock);
2120 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2121 if (sk->sk_family != st->family ||
2122 !net_eq(sock_net(sk), net)) {
2123 continue;
2124 }
2125 rc = sk;
2126 goto out;
2127 }
2128 st->state = TCP_SEQ_STATE_TIME_WAIT;
2129 inet_twsk_for_each(tw, node,
2130 &tcp_hashinfo.ehash[st->bucket].twchain) {
2131 if (tw->tw_family != st->family ||
2132 !net_eq(twsk_net(tw), net)) {
2133 continue;
2134 }
2135 rc = tw;
2136 goto out;
2137 }
2138 spin_unlock_bh(lock);
2139 st->state = TCP_SEQ_STATE_ESTABLISHED;
2140 }
2141out:
2142 return rc;
2143}
2144
2145static void *established_get_next(struct seq_file *seq, void *cur)
2146{
2147 struct sock *sk = cur;
2148 struct inet_timewait_sock *tw;
2149 struct hlist_nulls_node *node;
2150 struct tcp_iter_state *st = seq->private;
2151 struct net *net = seq_file_net(seq);
2152
2153 ++st->num;
2154 ++st->offset;
2155
2156 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2157 tw = cur;
2158 tw = tw_next(tw);
2159get_tw:
2160 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2161 tw = tw_next(tw);
2162 }
2163 if (tw) {
2164 cur = tw;
2165 goto out;
2166 }
2167 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2168 st->state = TCP_SEQ_STATE_ESTABLISHED;
2169
2170 /* Look for next non empty bucket */
2171 st->offset = 0;
2172 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2173 empty_bucket(st))
2174 ;
2175 if (st->bucket > tcp_hashinfo.ehash_mask)
2176 return NULL;
2177
2178 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2179 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2180 } else
2181 sk = sk_nulls_next(sk);
2182
2183 sk_nulls_for_each_from(sk, node) {
2184 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2185 goto found;
2186 }
2187
2188 st->state = TCP_SEQ_STATE_TIME_WAIT;
2189 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2190 goto get_tw;
2191found:
2192 cur = sk;
2193out:
2194 return cur;
2195}
2196
2197static void *established_get_idx(struct seq_file *seq, loff_t pos)
2198{
2199 struct tcp_iter_state *st = seq->private;
2200 void *rc;
2201
2202 st->bucket = 0;
2203 rc = established_get_first(seq);
2204
2205 while (rc && pos) {
2206 rc = established_get_next(seq, rc);
2207 --pos;
2208 }
2209 return rc;
2210}
2211
2212static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2213{
2214 void *rc;
2215 struct tcp_iter_state *st = seq->private;
2216
2217 st->state = TCP_SEQ_STATE_LISTENING;
2218 rc = listening_get_idx(seq, &pos);
2219
2220 if (!rc) {
2221 st->state = TCP_SEQ_STATE_ESTABLISHED;
2222 rc = established_get_idx(seq, pos);
2223 }
2224
2225 return rc;
2226}
2227
2228static void *tcp_seek_last_pos(struct seq_file *seq)
2229{
2230 struct tcp_iter_state *st = seq->private;
2231 int offset = st->offset;
2232 int orig_num = st->num;
2233 void *rc = NULL;
2234
2235 switch (st->state) {
2236 case TCP_SEQ_STATE_OPENREQ:
2237 case TCP_SEQ_STATE_LISTENING:
2238 if (st->bucket >= INET_LHTABLE_SIZE)
2239 break;
2240 st->state = TCP_SEQ_STATE_LISTENING;
2241 rc = listening_get_next(seq, NULL);
2242 while (offset-- && rc)
2243 rc = listening_get_next(seq, rc);
2244 if (rc)
2245 break;
2246 st->bucket = 0;
2247 /* Fallthrough */
2248 case TCP_SEQ_STATE_ESTABLISHED:
2249 case TCP_SEQ_STATE_TIME_WAIT:
2250 st->state = TCP_SEQ_STATE_ESTABLISHED;
2251 if (st->bucket > tcp_hashinfo.ehash_mask)
2252 break;
2253 rc = established_get_first(seq);
2254 while (offset-- && rc)
2255 rc = established_get_next(seq, rc);
2256 }
2257
2258 st->num = orig_num;
2259
2260 return rc;
2261}
2262
2263static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2264{
2265 struct tcp_iter_state *st = seq->private;
2266 void *rc;
2267
2268 if (*pos && *pos == st->last_pos) {
2269 rc = tcp_seek_last_pos(seq);
2270 if (rc)
2271 goto out;
2272 }
2273
2274 st->state = TCP_SEQ_STATE_LISTENING;
2275 st->num = 0;
2276 st->bucket = 0;
2277 st->offset = 0;
2278 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2279
2280out:
2281 st->last_pos = *pos;
2282 return rc;
2283}
2284
2285static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2286{
2287 struct tcp_iter_state *st = seq->private;
2288 void *rc = NULL;
2289
2290 if (v == SEQ_START_TOKEN) {
2291 rc = tcp_get_idx(seq, 0);
2292 goto out;
2293 }
2294
2295 switch (st->state) {
2296 case TCP_SEQ_STATE_OPENREQ:
2297 case TCP_SEQ_STATE_LISTENING:
2298 rc = listening_get_next(seq, v);
2299 if (!rc) {
2300 st->state = TCP_SEQ_STATE_ESTABLISHED;
2301 st->bucket = 0;
2302 st->offset = 0;
2303 rc = established_get_first(seq);
2304 }
2305 break;
2306 case TCP_SEQ_STATE_ESTABLISHED:
2307 case TCP_SEQ_STATE_TIME_WAIT:
2308 rc = established_get_next(seq, v);
2309 break;
2310 }
2311out:
2312 ++*pos;
2313 st->last_pos = *pos;
2314 return rc;
2315}
2316
2317static void tcp_seq_stop(struct seq_file *seq, void *v)
2318{
2319 struct tcp_iter_state *st = seq->private;
2320
2321 switch (st->state) {
2322 case TCP_SEQ_STATE_OPENREQ:
2323 if (v) {
2324 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2325 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2326 }
2327 case TCP_SEQ_STATE_LISTENING:
2328 if (v != SEQ_START_TOKEN)
2329 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2330 break;
2331 case TCP_SEQ_STATE_TIME_WAIT:
2332 case TCP_SEQ_STATE_ESTABLISHED:
2333 if (v)
2334 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2335 break;
2336 }
2337}
2338
2339static int tcp_seq_open(struct inode *inode, struct file *file)
2340{
2341 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2342 struct tcp_iter_state *s;
2343 int err;
2344
2345 err = seq_open_net(inode, file, &afinfo->seq_ops,
2346 sizeof(struct tcp_iter_state));
2347 if (err < 0)
2348 return err;
2349
2350 s = ((struct seq_file *)file->private_data)->private;
2351 s->family = afinfo->family;
2352 s->last_pos = 0;
2353 return 0;
2354}
2355
2356int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2357{
2358 int rc = 0;
2359 struct proc_dir_entry *p;
2360
2361 afinfo->seq_fops.open = tcp_seq_open;
2362 afinfo->seq_fops.read = seq_read;
2363 afinfo->seq_fops.llseek = seq_lseek;
2364 afinfo->seq_fops.release = seq_release_net;
2365
2366 afinfo->seq_ops.start = tcp_seq_start;
2367 afinfo->seq_ops.next = tcp_seq_next;
2368 afinfo->seq_ops.stop = tcp_seq_stop;
2369
2370 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2371 &afinfo->seq_fops, afinfo);
2372 if (!p)
2373 rc = -ENOMEM;
2374 return rc;
2375}
2376EXPORT_SYMBOL(tcp_proc_register);
2377
2378void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2379{
2380 proc_net_remove(net, afinfo->name);
2381}
2382EXPORT_SYMBOL(tcp_proc_unregister);
2383
2384static void get_openreq4(struct sock *sk, struct request_sock *req,
2385 struct seq_file *f, int i, int uid, int *len)
2386{
2387 const struct inet_request_sock *ireq = inet_rsk(req);
2388 int ttd = req->expires - jiffies;
2389
2390 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2391 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2392 i,
2393 ireq->loc_addr,
2394 ntohs(inet_sk(sk)->inet_sport),
2395 ireq->rmt_addr,
2396 ntohs(ireq->rmt_port),
2397 TCP_SYN_RECV,
2398 0, 0, /* could print option size, but that is af dependent. */
2399 1, /* timers active (only the expire timer) */
2400 jiffies_to_clock_t(ttd),
2401 req->retrans,
2402 uid,
2403 0, /* non standard timer */
2404 0, /* open_requests have no inode */
2405 atomic_read(&sk->sk_refcnt),
2406 req,
2407 len);
2408}
2409
2410static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2411{
2412 int timer_active;
2413 unsigned long timer_expires;
2414 struct tcp_sock *tp = tcp_sk(sk);
2415 const struct inet_connection_sock *icsk = inet_csk(sk);
2416 struct inet_sock *inet = inet_sk(sk);
2417 __be32 dest = inet->inet_daddr;
2418 __be32 src = inet->inet_rcv_saddr;
2419 __u16 destp = ntohs(inet->inet_dport);
2420 __u16 srcp = ntohs(inet->inet_sport);
2421 int rx_queue;
2422
2423 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2424 timer_active = 1;
2425 timer_expires = icsk->icsk_timeout;
2426 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2427 timer_active = 4;
2428 timer_expires = icsk->icsk_timeout;
2429 } else if (timer_pending(&sk->sk_timer)) {
2430 timer_active = 2;
2431 timer_expires = sk->sk_timer.expires;
2432 } else {
2433 timer_active = 0;
2434 timer_expires = jiffies;
2435 }
2436
2437 if (sk->sk_state == TCP_LISTEN)
2438 rx_queue = sk->sk_ack_backlog;
2439 else
2440 /*
2441 * because we dont lock socket, we might find a transient negative value
2442 */
2443 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2444
2445 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2446 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2447 i, src, srcp, dest, destp, sk->sk_state,
2448 tp->write_seq - tp->snd_una,
2449 rx_queue,
2450 timer_active,
2451 jiffies_to_clock_t(timer_expires - jiffies),
2452 icsk->icsk_retransmits,
2453 sock_i_uid(sk),
2454 icsk->icsk_probes_out,
2455 sock_i_ino(sk),
2456 atomic_read(&sk->sk_refcnt), sk,
2457 jiffies_to_clock_t(icsk->icsk_rto),
2458 jiffies_to_clock_t(icsk->icsk_ack.ato),
2459 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2460 tp->snd_cwnd,
2461 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2462 len);
2463}
2464
2465static void get_timewait4_sock(struct inet_timewait_sock *tw,
2466 struct seq_file *f, int i, int *len)
2467{
2468 __be32 dest, src;
2469 __u16 destp, srcp;
2470 int ttd = tw->tw_ttd - jiffies;
2471
2472 if (ttd < 0)
2473 ttd = 0;
2474
2475 dest = tw->tw_daddr;
2476 src = tw->tw_rcv_saddr;
2477 destp = ntohs(tw->tw_dport);
2478 srcp = ntohs(tw->tw_sport);
2479
2480 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2481 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2482 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2483 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2484 atomic_read(&tw->tw_refcnt), tw, len);
2485}
2486
2487#define TMPSZ 150
2488
2489static int tcp4_seq_show(struct seq_file *seq, void *v)
2490{
2491 struct tcp_iter_state *st;
2492 int len;
2493
2494 if (v == SEQ_START_TOKEN) {
2495 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2496 " sl local_address rem_address st tx_queue "
2497 "rx_queue tr tm->when retrnsmt uid timeout "
2498 "inode");
2499 goto out;
2500 }
2501 st = seq->private;
2502
2503 switch (st->state) {
2504 case TCP_SEQ_STATE_LISTENING:
2505 case TCP_SEQ_STATE_ESTABLISHED:
2506 get_tcp4_sock(v, seq, st->num, &len);
2507 break;
2508 case TCP_SEQ_STATE_OPENREQ:
2509 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2510 break;
2511 case TCP_SEQ_STATE_TIME_WAIT:
2512 get_timewait4_sock(v, seq, st->num, &len);
2513 break;
2514 }
2515 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2516out:
2517 return 0;
2518}
2519
2520static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2521 .name = "tcp",
2522 .family = AF_INET,
2523 .seq_fops = {
2524 .owner = THIS_MODULE,
2525 },
2526 .seq_ops = {
2527 .show = tcp4_seq_show,
2528 },
2529};
2530
2531static int __net_init tcp4_proc_init_net(struct net *net)
2532{
2533 return tcp_proc_register(net, &tcp4_seq_afinfo);
2534}
2535
2536static void __net_exit tcp4_proc_exit_net(struct net *net)
2537{
2538 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2539}
2540
2541static struct pernet_operations tcp4_net_ops = {
2542 .init = tcp4_proc_init_net,
2543 .exit = tcp4_proc_exit_net,
2544};
2545
2546int __init tcp4_proc_init(void)
2547{
2548 return register_pernet_subsys(&tcp4_net_ops);
2549}
2550
2551void tcp4_proc_exit(void)
2552{
2553 unregister_pernet_subsys(&tcp4_net_ops);
2554}
2555#endif /* CONFIG_PROC_FS */
2556
2557struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2558{
2559 const struct iphdr *iph = skb_gro_network_header(skb);
2560
2561 switch (skb->ip_summed) {
2562 case CHECKSUM_COMPLETE:
2563 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2564 skb->csum)) {
2565 skb->ip_summed = CHECKSUM_UNNECESSARY;
2566 break;
2567 }
2568
2569 /* fall through */
2570 case CHECKSUM_NONE:
2571 NAPI_GRO_CB(skb)->flush = 1;
2572 return NULL;
2573 }
2574
2575 return tcp_gro_receive(head, skb);
2576}
2577
2578int tcp4_gro_complete(struct sk_buff *skb)
2579{
2580 const struct iphdr *iph = ip_hdr(skb);
2581 struct tcphdr *th = tcp_hdr(skb);
2582
2583 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2584 iph->saddr, iph->daddr, 0);
2585 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2586
2587 return tcp_gro_complete(skb);
2588}
2589
2590struct proto tcp_prot = {
2591 .name = "TCP",
2592 .owner = THIS_MODULE,
2593 .close = tcp_close,
2594 .connect = tcp_v4_connect,
2595 .disconnect = tcp_disconnect,
2596 .accept = inet_csk_accept,
2597 .ioctl = tcp_ioctl,
2598 .init = tcp_v4_init_sock,
2599 .destroy = tcp_v4_destroy_sock,
2600 .shutdown = tcp_shutdown,
2601 .setsockopt = tcp_setsockopt,
2602 .getsockopt = tcp_getsockopt,
2603 .recvmsg = tcp_recvmsg,
2604 .sendmsg = tcp_sendmsg,
2605 .sendpage = tcp_sendpage,
2606 .backlog_rcv = tcp_v4_do_rcv,
2607 .hash = inet_hash,
2608 .unhash = inet_unhash,
2609 .get_port = inet_csk_get_port,
2610 .enter_memory_pressure = tcp_enter_memory_pressure,
2611 .sockets_allocated = &tcp_sockets_allocated,
2612 .orphan_count = &tcp_orphan_count,
2613 .memory_allocated = &tcp_memory_allocated,
2614 .memory_pressure = &tcp_memory_pressure,
2615 .sysctl_mem = sysctl_tcp_mem,
2616 .sysctl_wmem = sysctl_tcp_wmem,
2617 .sysctl_rmem = sysctl_tcp_rmem,
2618 .max_header = MAX_TCP_HEADER,
2619 .obj_size = sizeof(struct tcp_sock),
2620 .slab_flags = SLAB_DESTROY_BY_RCU,
2621 .twsk_prot = &tcp_timewait_sock_ops,
2622 .rsk_prot = &tcp_request_sock_ops,
2623 .h.hashinfo = &tcp_hashinfo,
2624 .no_autobind = true,
2625#ifdef CONFIG_COMPAT
2626 .compat_setsockopt = compat_tcp_setsockopt,
2627 .compat_getsockopt = compat_tcp_getsockopt,
2628#endif
2629};
2630EXPORT_SYMBOL(tcp_prot);
2631
2632
2633static int __net_init tcp_sk_init(struct net *net)
2634{
2635 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2636 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2637}
2638
2639static void __net_exit tcp_sk_exit(struct net *net)
2640{
2641 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2642}
2643
2644static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2645{
2646 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2647}
2648
2649static struct pernet_operations __net_initdata tcp_sk_ops = {
2650 .init = tcp_sk_init,
2651 .exit = tcp_sk_exit,
2652 .exit_batch = tcp_sk_exit_batch,
2653};
2654
2655void __init tcp_v4_init(void)
2656{
2657 inet_hashinfo_init(&tcp_hashinfo);
2658 if (register_pernet_subsys(&tcp_sk_ops))
2659 panic("Failed to create the TCP control socket.\n");
2660}
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 /* inet_twsk_hashdance() sets sk_refcnt after putting twsk
158 * and releasing the bucket lock.
159 */
160 if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt)))
161 return 0;
162
163 /* In case of repair and re-using TIME-WAIT sockets we still
164 * want to be sure that it is safe as above but honor the
165 * sequence numbers and time stamps set as part of the repair
166 * process.
167 *
168 * Without this check re-using a TIME-WAIT socket with TCP
169 * repair would accumulate a -1 on the repair assigned
170 * sequence number. The first time it is reused the sequence
171 * is -1, the second time -2, etc. This fixes that issue
172 * without appearing to create any others.
173 */
174 if (likely(!tp->repair)) {
175 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
176
177 if (!seq)
178 seq = 1;
179 WRITE_ONCE(tp->write_seq, seq);
180 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
181 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
182 }
183
184 return 1;
185 }
186
187 return 0;
188}
189EXPORT_SYMBOL_GPL(tcp_twsk_unique);
190
191static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
192 int addr_len)
193{
194 /* This check is replicated from tcp_v4_connect() and intended to
195 * prevent BPF program called below from accessing bytes that are out
196 * of the bound specified by user in addr_len.
197 */
198 if (addr_len < sizeof(struct sockaddr_in))
199 return -EINVAL;
200
201 sock_owned_by_me(sk);
202
203 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
204}
205
206/* This will initiate an outgoing connection. */
207int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
208{
209 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
210 struct inet_timewait_death_row *tcp_death_row;
211 struct inet_sock *inet = inet_sk(sk);
212 struct tcp_sock *tp = tcp_sk(sk);
213 struct ip_options_rcu *inet_opt;
214 struct net *net = sock_net(sk);
215 __be16 orig_sport, orig_dport;
216 __be32 daddr, nexthop;
217 struct flowi4 *fl4;
218 struct rtable *rt;
219 int err;
220
221 if (addr_len < sizeof(struct sockaddr_in))
222 return -EINVAL;
223
224 if (usin->sin_family != AF_INET)
225 return -EAFNOSUPPORT;
226
227 nexthop = daddr = usin->sin_addr.s_addr;
228 inet_opt = rcu_dereference_protected(inet->inet_opt,
229 lockdep_sock_is_held(sk));
230 if (inet_opt && inet_opt->opt.srr) {
231 if (!daddr)
232 return -EINVAL;
233 nexthop = inet_opt->opt.faddr;
234 }
235
236 orig_sport = inet->inet_sport;
237 orig_dport = usin->sin_port;
238 fl4 = &inet->cork.fl.u.ip4;
239 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
240 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
241 orig_dport, sk);
242 if (IS_ERR(rt)) {
243 err = PTR_ERR(rt);
244 if (err == -ENETUNREACH)
245 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
246 return err;
247 }
248
249 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
250 ip_rt_put(rt);
251 return -ENETUNREACH;
252 }
253
254 if (!inet_opt || !inet_opt->opt.srr)
255 daddr = fl4->daddr;
256
257 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
258
259 if (!inet->inet_saddr) {
260 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
261 if (err) {
262 ip_rt_put(rt);
263 return err;
264 }
265 } else {
266 sk_rcv_saddr_set(sk, inet->inet_saddr);
267 }
268
269 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
270 /* Reset inherited state */
271 tp->rx_opt.ts_recent = 0;
272 tp->rx_opt.ts_recent_stamp = 0;
273 if (likely(!tp->repair))
274 WRITE_ONCE(tp->write_seq, 0);
275 }
276
277 inet->inet_dport = usin->sin_port;
278 sk_daddr_set(sk, daddr);
279
280 inet_csk(sk)->icsk_ext_hdr_len = 0;
281 if (inet_opt)
282 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
283
284 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
285
286 /* Socket identity is still unknown (sport may be zero).
287 * However we set state to SYN-SENT and not releasing socket
288 * lock select source port, enter ourselves into the hash tables and
289 * complete initialization after this.
290 */
291 tcp_set_state(sk, TCP_SYN_SENT);
292 err = inet_hash_connect(tcp_death_row, sk);
293 if (err)
294 goto failure;
295
296 sk_set_txhash(sk);
297
298 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
299 inet->inet_sport, inet->inet_dport, sk);
300 if (IS_ERR(rt)) {
301 err = PTR_ERR(rt);
302 rt = NULL;
303 goto failure;
304 }
305 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
306 /* OK, now commit destination to socket. */
307 sk->sk_gso_type = SKB_GSO_TCPV4;
308 sk_setup_caps(sk, &rt->dst);
309 rt = NULL;
310
311 if (likely(!tp->repair)) {
312 if (!tp->write_seq)
313 WRITE_ONCE(tp->write_seq,
314 secure_tcp_seq(inet->inet_saddr,
315 inet->inet_daddr,
316 inet->inet_sport,
317 usin->sin_port));
318 WRITE_ONCE(tp->tsoffset,
319 secure_tcp_ts_off(net, inet->inet_saddr,
320 inet->inet_daddr));
321 }
322
323 atomic_set(&inet->inet_id, get_random_u16());
324
325 if (tcp_fastopen_defer_connect(sk, &err))
326 return err;
327 if (err)
328 goto failure;
329
330 err = tcp_connect(sk);
331
332 if (err)
333 goto failure;
334
335 return 0;
336
337failure:
338 /*
339 * This unhashes the socket and releases the local port,
340 * if necessary.
341 */
342 tcp_set_state(sk, TCP_CLOSE);
343 inet_bhash2_reset_saddr(sk);
344 ip_rt_put(rt);
345 sk->sk_route_caps = 0;
346 inet->inet_dport = 0;
347 return err;
348}
349EXPORT_SYMBOL(tcp_v4_connect);
350
351/*
352 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
353 * It can be called through tcp_release_cb() if socket was owned by user
354 * at the time tcp_v4_err() was called to handle ICMP message.
355 */
356void tcp_v4_mtu_reduced(struct sock *sk)
357{
358 struct inet_sock *inet = inet_sk(sk);
359 struct dst_entry *dst;
360 u32 mtu;
361
362 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
363 return;
364 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
365 dst = inet_csk_update_pmtu(sk, mtu);
366 if (!dst)
367 return;
368
369 /* Something is about to be wrong... Remember soft error
370 * for the case, if this connection will not able to recover.
371 */
372 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
373 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
374
375 mtu = dst_mtu(dst);
376
377 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
378 ip_sk_accept_pmtu(sk) &&
379 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
380 tcp_sync_mss(sk, mtu);
381
382 /* Resend the TCP packet because it's
383 * clear that the old packet has been
384 * dropped. This is the new "fast" path mtu
385 * discovery.
386 */
387 tcp_simple_retransmit(sk);
388 } /* else let the usual retransmit timer handle it */
389}
390EXPORT_SYMBOL(tcp_v4_mtu_reduced);
391
392static void do_redirect(struct sk_buff *skb, struct sock *sk)
393{
394 struct dst_entry *dst = __sk_dst_check(sk, 0);
395
396 if (dst)
397 dst->ops->redirect(dst, sk, skb);
398}
399
400
401/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
402void tcp_req_err(struct sock *sk, u32 seq, bool abort)
403{
404 struct request_sock *req = inet_reqsk(sk);
405 struct net *net = sock_net(sk);
406
407 /* ICMPs are not backlogged, hence we cannot get
408 * an established socket here.
409 */
410 if (seq != tcp_rsk(req)->snt_isn) {
411 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
412 } else if (abort) {
413 /*
414 * Still in SYN_RECV, just remove it silently.
415 * There is no good way to pass the error to the newly
416 * created socket, and POSIX does not want network
417 * errors returned from accept().
418 */
419 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
420 tcp_listendrop(req->rsk_listener);
421 }
422 reqsk_put(req);
423}
424EXPORT_SYMBOL(tcp_req_err);
425
426/* TCP-LD (RFC 6069) logic */
427void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
428{
429 struct inet_connection_sock *icsk = inet_csk(sk);
430 struct tcp_sock *tp = tcp_sk(sk);
431 struct sk_buff *skb;
432 s32 remaining;
433 u32 delta_us;
434
435 if (sock_owned_by_user(sk))
436 return;
437
438 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
439 !icsk->icsk_backoff)
440 return;
441
442 skb = tcp_rtx_queue_head(sk);
443 if (WARN_ON_ONCE(!skb))
444 return;
445
446 icsk->icsk_backoff--;
447 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
448 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
449
450 tcp_mstamp_refresh(tp);
451 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
452 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
453
454 if (remaining > 0) {
455 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
456 remaining, TCP_RTO_MAX);
457 } else {
458 /* RTO revert clocked out retransmission.
459 * Will retransmit now.
460 */
461 tcp_retransmit_timer(sk);
462 }
463}
464EXPORT_SYMBOL(tcp_ld_RTO_revert);
465
466/*
467 * This routine is called by the ICMP module when it gets some
468 * sort of error condition. If err < 0 then the socket should
469 * be closed and the error returned to the user. If err > 0
470 * it's just the icmp type << 8 | icmp code. After adjustment
471 * header points to the first 8 bytes of the tcp header. We need
472 * to find the appropriate port.
473 *
474 * The locking strategy used here is very "optimistic". When
475 * someone else accesses the socket the ICMP is just dropped
476 * and for some paths there is no check at all.
477 * A more general error queue to queue errors for later handling
478 * is probably better.
479 *
480 */
481
482int tcp_v4_err(struct sk_buff *skb, u32 info)
483{
484 const struct iphdr *iph = (const struct iphdr *)skb->data;
485 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
486 struct tcp_sock *tp;
487 const int type = icmp_hdr(skb)->type;
488 const int code = icmp_hdr(skb)->code;
489 struct sock *sk;
490 struct request_sock *fastopen;
491 u32 seq, snd_una;
492 int err;
493 struct net *net = dev_net(skb->dev);
494
495 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
496 iph->daddr, th->dest, iph->saddr,
497 ntohs(th->source), inet_iif(skb), 0);
498 if (!sk) {
499 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
500 return -ENOENT;
501 }
502 if (sk->sk_state == TCP_TIME_WAIT) {
503 /* To increase the counter of ignored icmps for TCP-AO */
504 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
505 inet_twsk_put(inet_twsk(sk));
506 return 0;
507 }
508 seq = ntohl(th->seq);
509 if (sk->sk_state == TCP_NEW_SYN_RECV) {
510 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
511 type == ICMP_TIME_EXCEEDED ||
512 (type == ICMP_DEST_UNREACH &&
513 (code == ICMP_NET_UNREACH ||
514 code == ICMP_HOST_UNREACH)));
515 return 0;
516 }
517
518 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
519 sock_put(sk);
520 return 0;
521 }
522
523 bh_lock_sock(sk);
524 /* If too many ICMPs get dropped on busy
525 * servers this needs to be solved differently.
526 * We do take care of PMTU discovery (RFC1191) special case :
527 * we can receive locally generated ICMP messages while socket is held.
528 */
529 if (sock_owned_by_user(sk)) {
530 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
531 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
532 }
533 if (sk->sk_state == TCP_CLOSE)
534 goto out;
535
536 if (static_branch_unlikely(&ip4_min_ttl)) {
537 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
538 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
539 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
540 goto out;
541 }
542 }
543
544 tp = tcp_sk(sk);
545 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
546 fastopen = rcu_dereference(tp->fastopen_rsk);
547 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
548 if (sk->sk_state != TCP_LISTEN &&
549 !between(seq, snd_una, tp->snd_nxt)) {
550 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
551 goto out;
552 }
553
554 switch (type) {
555 case ICMP_REDIRECT:
556 if (!sock_owned_by_user(sk))
557 do_redirect(skb, sk);
558 goto out;
559 case ICMP_SOURCE_QUENCH:
560 /* Just silently ignore these. */
561 goto out;
562 case ICMP_PARAMETERPROB:
563 err = EPROTO;
564 break;
565 case ICMP_DEST_UNREACH:
566 if (code > NR_ICMP_UNREACH)
567 goto out;
568
569 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
570 /* We are not interested in TCP_LISTEN and open_requests
571 * (SYN-ACKs send out by Linux are always <576bytes so
572 * they should go through unfragmented).
573 */
574 if (sk->sk_state == TCP_LISTEN)
575 goto out;
576
577 WRITE_ONCE(tp->mtu_info, info);
578 if (!sock_owned_by_user(sk)) {
579 tcp_v4_mtu_reduced(sk);
580 } else {
581 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
582 sock_hold(sk);
583 }
584 goto out;
585 }
586
587 err = icmp_err_convert[code].errno;
588 /* check if this ICMP message allows revert of backoff.
589 * (see RFC 6069)
590 */
591 if (!fastopen &&
592 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
593 tcp_ld_RTO_revert(sk, seq);
594 break;
595 case ICMP_TIME_EXCEEDED:
596 err = EHOSTUNREACH;
597 break;
598 default:
599 goto out;
600 }
601
602 switch (sk->sk_state) {
603 case TCP_SYN_SENT:
604 case TCP_SYN_RECV:
605 /* Only in fast or simultaneous open. If a fast open socket is
606 * already accepted it is treated as a connected one below.
607 */
608 if (fastopen && !fastopen->sk)
609 break;
610
611 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
612
613 if (!sock_owned_by_user(sk)) {
614 WRITE_ONCE(sk->sk_err, err);
615
616 sk_error_report(sk);
617
618 tcp_done(sk);
619 } else {
620 WRITE_ONCE(sk->sk_err_soft, err);
621 }
622 goto out;
623 }
624
625 /* If we've already connected we will keep trying
626 * until we time out, or the user gives up.
627 *
628 * rfc1122 4.2.3.9 allows to consider as hard errors
629 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
630 * but it is obsoleted by pmtu discovery).
631 *
632 * Note, that in modern internet, where routing is unreliable
633 * and in each dark corner broken firewalls sit, sending random
634 * errors ordered by their masters even this two messages finally lose
635 * their original sense (even Linux sends invalid PORT_UNREACHs)
636 *
637 * Now we are in compliance with RFCs.
638 * --ANK (980905)
639 */
640
641 if (!sock_owned_by_user(sk) &&
642 inet_test_bit(RECVERR, sk)) {
643 WRITE_ONCE(sk->sk_err, err);
644 sk_error_report(sk);
645 } else { /* Only an error on timeout */
646 WRITE_ONCE(sk->sk_err_soft, err);
647 }
648
649out:
650 bh_unlock_sock(sk);
651 sock_put(sk);
652 return 0;
653}
654
655void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
656{
657 struct tcphdr *th = tcp_hdr(skb);
658
659 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
660 skb->csum_start = skb_transport_header(skb) - skb->head;
661 skb->csum_offset = offsetof(struct tcphdr, check);
662}
663
664/* This routine computes an IPv4 TCP checksum. */
665void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
666{
667 const struct inet_sock *inet = inet_sk(sk);
668
669 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
670}
671EXPORT_SYMBOL(tcp_v4_send_check);
672
673#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
674
675static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
676 const struct tcp_ao_hdr *aoh,
677 struct ip_reply_arg *arg, struct tcphdr *reply,
678 __be32 reply_options[REPLY_OPTIONS_LEN])
679{
680#ifdef CONFIG_TCP_AO
681 int sdif = tcp_v4_sdif(skb);
682 int dif = inet_iif(skb);
683 int l3index = sdif ? dif : 0;
684 bool allocated_traffic_key;
685 struct tcp_ao_key *key;
686 char *traffic_key;
687 bool drop = true;
688 u32 ao_sne = 0;
689 u8 keyid;
690
691 rcu_read_lock();
692 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
693 &key, &traffic_key, &allocated_traffic_key,
694 &keyid, &ao_sne))
695 goto out;
696
697 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
698 (aoh->rnext_keyid << 8) | keyid);
699 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
700 reply->doff = arg->iov[0].iov_len / 4;
701
702 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
703 key, traffic_key,
704 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
705 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
706 reply, ao_sne))
707 goto out;
708 drop = false;
709out:
710 rcu_read_unlock();
711 if (allocated_traffic_key)
712 kfree(traffic_key);
713 return drop;
714#else
715 return true;
716#endif
717}
718
719/*
720 * This routine will send an RST to the other tcp.
721 *
722 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
723 * for reset.
724 * Answer: if a packet caused RST, it is not for a socket
725 * existing in our system, if it is matched to a socket,
726 * it is just duplicate segment or bug in other side's TCP.
727 * So that we build reply only basing on parameters
728 * arrived with segment.
729 * Exception: precedence violation. We do not implement it in any case.
730 */
731
732static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
733{
734 const struct tcphdr *th = tcp_hdr(skb);
735 struct {
736 struct tcphdr th;
737 __be32 opt[REPLY_OPTIONS_LEN];
738 } rep;
739 const __u8 *md5_hash_location = NULL;
740 const struct tcp_ao_hdr *aoh;
741 struct ip_reply_arg arg;
742#ifdef CONFIG_TCP_MD5SIG
743 struct tcp_md5sig_key *key = NULL;
744 unsigned char newhash[16];
745 struct sock *sk1 = NULL;
746 int genhash;
747#endif
748 u64 transmit_time = 0;
749 struct sock *ctl_sk;
750 struct net *net;
751 u32 txhash = 0;
752
753 /* Never send a reset in response to a reset. */
754 if (th->rst)
755 return;
756
757 /* If sk not NULL, it means we did a successful lookup and incoming
758 * route had to be correct. prequeue might have dropped our dst.
759 */
760 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
761 return;
762
763 /* Swap the send and the receive. */
764 memset(&rep, 0, sizeof(rep));
765 rep.th.dest = th->source;
766 rep.th.source = th->dest;
767 rep.th.doff = sizeof(struct tcphdr) / 4;
768 rep.th.rst = 1;
769
770 if (th->ack) {
771 rep.th.seq = th->ack_seq;
772 } else {
773 rep.th.ack = 1;
774 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
775 skb->len - (th->doff << 2));
776 }
777
778 memset(&arg, 0, sizeof(arg));
779 arg.iov[0].iov_base = (unsigned char *)&rep;
780 arg.iov[0].iov_len = sizeof(rep.th);
781
782 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
783
784 /* Invalid TCP option size or twice included auth */
785 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
786 return;
787
788 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
789 return;
790
791#ifdef CONFIG_TCP_MD5SIG
792 rcu_read_lock();
793 if (sk && sk_fullsock(sk)) {
794 const union tcp_md5_addr *addr;
795 int l3index;
796
797 /* sdif set, means packet ingressed via a device
798 * in an L3 domain and inet_iif is set to it.
799 */
800 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
801 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
802 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
803 } else if (md5_hash_location) {
804 const union tcp_md5_addr *addr;
805 int sdif = tcp_v4_sdif(skb);
806 int dif = inet_iif(skb);
807 int l3index;
808
809 /*
810 * active side is lost. Try to find listening socket through
811 * source port, and then find md5 key through listening socket.
812 * we are not loose security here:
813 * Incoming packet is checked with md5 hash with finding key,
814 * no RST generated if md5 hash doesn't match.
815 */
816 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
817 NULL, 0, ip_hdr(skb)->saddr,
818 th->source, ip_hdr(skb)->daddr,
819 ntohs(th->source), dif, sdif);
820 /* don't send rst if it can't find key */
821 if (!sk1)
822 goto out;
823
824 /* sdif set, means packet ingressed via a device
825 * in an L3 domain and dif is set to it.
826 */
827 l3index = sdif ? dif : 0;
828 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
829 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
830 if (!key)
831 goto out;
832
833
834 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
835 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
836 goto out;
837
838 }
839
840 if (key) {
841 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
842 (TCPOPT_NOP << 16) |
843 (TCPOPT_MD5SIG << 8) |
844 TCPOLEN_MD5SIG);
845 /* Update length and the length the header thinks exists */
846 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
847 rep.th.doff = arg.iov[0].iov_len / 4;
848
849 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
850 key, ip_hdr(skb)->saddr,
851 ip_hdr(skb)->daddr, &rep.th);
852 }
853#endif
854 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
855 if (rep.opt[0] == 0) {
856 __be32 mrst = mptcp_reset_option(skb);
857
858 if (mrst) {
859 rep.opt[0] = mrst;
860 arg.iov[0].iov_len += sizeof(mrst);
861 rep.th.doff = arg.iov[0].iov_len / 4;
862 }
863 }
864
865 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
866 ip_hdr(skb)->saddr, /* XXX */
867 arg.iov[0].iov_len, IPPROTO_TCP, 0);
868 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
869 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
870
871 /* When socket is gone, all binding information is lost.
872 * routing might fail in this case. No choice here, if we choose to force
873 * input interface, we will misroute in case of asymmetric route.
874 */
875 if (sk) {
876 arg.bound_dev_if = sk->sk_bound_dev_if;
877 if (sk_fullsock(sk))
878 trace_tcp_send_reset(sk, skb);
879 }
880
881 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
882 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
883
884 arg.tos = ip_hdr(skb)->tos;
885 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
886 local_bh_disable();
887 ctl_sk = this_cpu_read(ipv4_tcp_sk);
888 sock_net_set(ctl_sk, net);
889 if (sk) {
890 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
891 inet_twsk(sk)->tw_mark : sk->sk_mark;
892 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
893 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
894 transmit_time = tcp_transmit_time(sk);
895 xfrm_sk_clone_policy(ctl_sk, sk);
896 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
897 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
898 } else {
899 ctl_sk->sk_mark = 0;
900 ctl_sk->sk_priority = 0;
901 }
902 ip_send_unicast_reply(ctl_sk,
903 skb, &TCP_SKB_CB(skb)->header.h4.opt,
904 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
905 &arg, arg.iov[0].iov_len,
906 transmit_time, txhash);
907
908 xfrm_sk_free_policy(ctl_sk);
909 sock_net_set(ctl_sk, &init_net);
910 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
911 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
912 local_bh_enable();
913
914#ifdef CONFIG_TCP_MD5SIG
915out:
916 rcu_read_unlock();
917#endif
918}
919
920/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
921 outside socket context is ugly, certainly. What can I do?
922 */
923
924static void tcp_v4_send_ack(const struct sock *sk,
925 struct sk_buff *skb, u32 seq, u32 ack,
926 u32 win, u32 tsval, u32 tsecr, int oif,
927 struct tcp_key *key,
928 int reply_flags, u8 tos, u32 txhash)
929{
930 const struct tcphdr *th = tcp_hdr(skb);
931 struct {
932 struct tcphdr th;
933 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
934 } rep;
935 struct net *net = sock_net(sk);
936 struct ip_reply_arg arg;
937 struct sock *ctl_sk;
938 u64 transmit_time;
939
940 memset(&rep.th, 0, sizeof(struct tcphdr));
941 memset(&arg, 0, sizeof(arg));
942
943 arg.iov[0].iov_base = (unsigned char *)&rep;
944 arg.iov[0].iov_len = sizeof(rep.th);
945 if (tsecr) {
946 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
947 (TCPOPT_TIMESTAMP << 8) |
948 TCPOLEN_TIMESTAMP);
949 rep.opt[1] = htonl(tsval);
950 rep.opt[2] = htonl(tsecr);
951 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
952 }
953
954 /* Swap the send and the receive. */
955 rep.th.dest = th->source;
956 rep.th.source = th->dest;
957 rep.th.doff = arg.iov[0].iov_len / 4;
958 rep.th.seq = htonl(seq);
959 rep.th.ack_seq = htonl(ack);
960 rep.th.ack = 1;
961 rep.th.window = htons(win);
962
963#ifdef CONFIG_TCP_MD5SIG
964 if (tcp_key_is_md5(key)) {
965 int offset = (tsecr) ? 3 : 0;
966
967 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
968 (TCPOPT_NOP << 16) |
969 (TCPOPT_MD5SIG << 8) |
970 TCPOLEN_MD5SIG);
971 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
972 rep.th.doff = arg.iov[0].iov_len/4;
973
974 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
975 key->md5_key, ip_hdr(skb)->saddr,
976 ip_hdr(skb)->daddr, &rep.th);
977 }
978#endif
979#ifdef CONFIG_TCP_AO
980 if (tcp_key_is_ao(key)) {
981 int offset = (tsecr) ? 3 : 0;
982
983 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
984 (tcp_ao_len(key->ao_key) << 16) |
985 (key->ao_key->sndid << 8) |
986 key->rcv_next);
987 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
988 rep.th.doff = arg.iov[0].iov_len / 4;
989
990 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
991 key->ao_key, key->traffic_key,
992 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
993 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
994 &rep.th, key->sne);
995 }
996#endif
997 arg.flags = reply_flags;
998 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
999 ip_hdr(skb)->saddr, /* XXX */
1000 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1001 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1002 if (oif)
1003 arg.bound_dev_if = oif;
1004 arg.tos = tos;
1005 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1006 local_bh_disable();
1007 ctl_sk = this_cpu_read(ipv4_tcp_sk);
1008 sock_net_set(ctl_sk, net);
1009 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1010 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1011 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1012 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1013 transmit_time = tcp_transmit_time(sk);
1014 ip_send_unicast_reply(ctl_sk,
1015 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1016 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1017 &arg, arg.iov[0].iov_len,
1018 transmit_time, txhash);
1019
1020 sock_net_set(ctl_sk, &init_net);
1021 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1022 local_bh_enable();
1023}
1024
1025static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1026{
1027 struct inet_timewait_sock *tw = inet_twsk(sk);
1028 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1029 struct tcp_key key = {};
1030#ifdef CONFIG_TCP_AO
1031 struct tcp_ao_info *ao_info;
1032
1033 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1034 /* FIXME: the segment to-be-acked is not verified yet */
1035 ao_info = rcu_dereference(tcptw->ao_info);
1036 if (ao_info) {
1037 const struct tcp_ao_hdr *aoh;
1038
1039 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1040 inet_twsk_put(tw);
1041 return;
1042 }
1043
1044 if (aoh)
1045 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
1046 }
1047 }
1048 if (key.ao_key) {
1049 struct tcp_ao_key *rnext_key;
1050
1051 key.traffic_key = snd_other_key(key.ao_key);
1052 key.sne = READ_ONCE(ao_info->snd_sne);
1053 rnext_key = READ_ONCE(ao_info->rnext_key);
1054 key.rcv_next = rnext_key->rcvid;
1055 key.type = TCP_KEY_AO;
1056#else
1057 if (0) {
1058#endif
1059#ifdef CONFIG_TCP_MD5SIG
1060 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1061 key.md5_key = tcp_twsk_md5_key(tcptw);
1062 if (key.md5_key)
1063 key.type = TCP_KEY_MD5;
1064#endif
1065 }
1066
1067 tcp_v4_send_ack(sk, skb,
1068 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1069 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1070 tcp_tw_tsval(tcptw),
1071 tcptw->tw_ts_recent,
1072 tw->tw_bound_dev_if, &key,
1073 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1074 tw->tw_tos,
1075 tw->tw_txhash);
1076
1077 inet_twsk_put(tw);
1078}
1079
1080static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1081 struct request_sock *req)
1082{
1083 struct tcp_key key = {};
1084
1085 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1086 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1087 */
1088 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1089 tcp_sk(sk)->snd_nxt;
1090
1091#ifdef CONFIG_TCP_AO
1092 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1093 tcp_rsk_used_ao(req)) {
1094 const union tcp_md5_addr *addr;
1095 const struct tcp_ao_hdr *aoh;
1096 int l3index;
1097
1098 /* Invalid TCP option size or twice included auth */
1099 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1100 return;
1101 if (!aoh)
1102 return;
1103
1104 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1105 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1106 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1107 aoh->rnext_keyid, -1);
1108 if (unlikely(!key.ao_key)) {
1109 /* Send ACK with any matching MKT for the peer */
1110 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1111 /* Matching key disappeared (user removed the key?)
1112 * let the handshake timeout.
1113 */
1114 if (!key.ao_key) {
1115 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1116 addr,
1117 ntohs(tcp_hdr(skb)->source),
1118 &ip_hdr(skb)->daddr,
1119 ntohs(tcp_hdr(skb)->dest));
1120 return;
1121 }
1122 }
1123 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1124 if (!key.traffic_key)
1125 return;
1126
1127 key.type = TCP_KEY_AO;
1128 key.rcv_next = aoh->keyid;
1129 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1130#else
1131 if (0) {
1132#endif
1133#ifdef CONFIG_TCP_MD5SIG
1134 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1135 const union tcp_md5_addr *addr;
1136 int l3index;
1137
1138 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1139 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1140 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1141 if (key.md5_key)
1142 key.type = TCP_KEY_MD5;
1143#endif
1144 }
1145
1146 /* RFC 7323 2.3
1147 * The window field (SEG.WND) of every outgoing segment, with the
1148 * exception of <SYN> segments, MUST be right-shifted by
1149 * Rcv.Wind.Shift bits:
1150 */
1151 tcp_v4_send_ack(sk, skb, seq,
1152 tcp_rsk(req)->rcv_nxt,
1153 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1154 tcp_rsk_tsval(tcp_rsk(req)),
1155 READ_ONCE(req->ts_recent),
1156 0, &key,
1157 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1158 ip_hdr(skb)->tos,
1159 READ_ONCE(tcp_rsk(req)->txhash));
1160 if (tcp_key_is_ao(&key))
1161 kfree(key.traffic_key);
1162}
1163
1164/*
1165 * Send a SYN-ACK after having received a SYN.
1166 * This still operates on a request_sock only, not on a big
1167 * socket.
1168 */
1169static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1170 struct flowi *fl,
1171 struct request_sock *req,
1172 struct tcp_fastopen_cookie *foc,
1173 enum tcp_synack_type synack_type,
1174 struct sk_buff *syn_skb)
1175{
1176 const struct inet_request_sock *ireq = inet_rsk(req);
1177 struct flowi4 fl4;
1178 int err = -1;
1179 struct sk_buff *skb;
1180 u8 tos;
1181
1182 /* First, grab a route. */
1183 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1184 return -1;
1185
1186 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1187
1188 if (skb) {
1189 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1190
1191 tos = READ_ONCE(inet_sk(sk)->tos);
1192
1193 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1194 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1195 (tos & INET_ECN_MASK);
1196
1197 if (!INET_ECN_is_capable(tos) &&
1198 tcp_bpf_ca_needs_ecn((struct sock *)req))
1199 tos |= INET_ECN_ECT_0;
1200
1201 rcu_read_lock();
1202 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1203 ireq->ir_rmt_addr,
1204 rcu_dereference(ireq->ireq_opt),
1205 tos);
1206 rcu_read_unlock();
1207 err = net_xmit_eval(err);
1208 }
1209
1210 return err;
1211}
1212
1213/*
1214 * IPv4 request_sock destructor.
1215 */
1216static void tcp_v4_reqsk_destructor(struct request_sock *req)
1217{
1218 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1219}
1220
1221#ifdef CONFIG_TCP_MD5SIG
1222/*
1223 * RFC2385 MD5 checksumming requires a mapping of
1224 * IP address->MD5 Key.
1225 * We need to maintain these in the sk structure.
1226 */
1227
1228DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1229EXPORT_SYMBOL(tcp_md5_needed);
1230
1231static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1232{
1233 if (!old)
1234 return true;
1235
1236 /* l3index always overrides non-l3index */
1237 if (old->l3index && new->l3index == 0)
1238 return false;
1239 if (old->l3index == 0 && new->l3index)
1240 return true;
1241
1242 return old->prefixlen < new->prefixlen;
1243}
1244
1245/* Find the Key structure for an address. */
1246struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1247 const union tcp_md5_addr *addr,
1248 int family, bool any_l3index)
1249{
1250 const struct tcp_sock *tp = tcp_sk(sk);
1251 struct tcp_md5sig_key *key;
1252 const struct tcp_md5sig_info *md5sig;
1253 __be32 mask;
1254 struct tcp_md5sig_key *best_match = NULL;
1255 bool match;
1256
1257 /* caller either holds rcu_read_lock() or socket lock */
1258 md5sig = rcu_dereference_check(tp->md5sig_info,
1259 lockdep_sock_is_held(sk));
1260 if (!md5sig)
1261 return NULL;
1262
1263 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1264 lockdep_sock_is_held(sk)) {
1265 if (key->family != family)
1266 continue;
1267 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1268 key->l3index != l3index)
1269 continue;
1270 if (family == AF_INET) {
1271 mask = inet_make_mask(key->prefixlen);
1272 match = (key->addr.a4.s_addr & mask) ==
1273 (addr->a4.s_addr & mask);
1274#if IS_ENABLED(CONFIG_IPV6)
1275 } else if (family == AF_INET6) {
1276 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1277 key->prefixlen);
1278#endif
1279 } else {
1280 match = false;
1281 }
1282
1283 if (match && better_md5_match(best_match, key))
1284 best_match = key;
1285 }
1286 return best_match;
1287}
1288EXPORT_SYMBOL(__tcp_md5_do_lookup);
1289
1290static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1291 const union tcp_md5_addr *addr,
1292 int family, u8 prefixlen,
1293 int l3index, u8 flags)
1294{
1295 const struct tcp_sock *tp = tcp_sk(sk);
1296 struct tcp_md5sig_key *key;
1297 unsigned int size = sizeof(struct in_addr);
1298 const struct tcp_md5sig_info *md5sig;
1299
1300 /* caller either holds rcu_read_lock() or socket lock */
1301 md5sig = rcu_dereference_check(tp->md5sig_info,
1302 lockdep_sock_is_held(sk));
1303 if (!md5sig)
1304 return NULL;
1305#if IS_ENABLED(CONFIG_IPV6)
1306 if (family == AF_INET6)
1307 size = sizeof(struct in6_addr);
1308#endif
1309 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1310 lockdep_sock_is_held(sk)) {
1311 if (key->family != family)
1312 continue;
1313 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1314 continue;
1315 if (key->l3index != l3index)
1316 continue;
1317 if (!memcmp(&key->addr, addr, size) &&
1318 key->prefixlen == prefixlen)
1319 return key;
1320 }
1321 return NULL;
1322}
1323
1324struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1325 const struct sock *addr_sk)
1326{
1327 const union tcp_md5_addr *addr;
1328 int l3index;
1329
1330 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1331 addr_sk->sk_bound_dev_if);
1332 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1333 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1334}
1335EXPORT_SYMBOL(tcp_v4_md5_lookup);
1336
1337static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1338{
1339 struct tcp_sock *tp = tcp_sk(sk);
1340 struct tcp_md5sig_info *md5sig;
1341
1342 md5sig = kmalloc(sizeof(*md5sig), gfp);
1343 if (!md5sig)
1344 return -ENOMEM;
1345
1346 sk_gso_disable(sk);
1347 INIT_HLIST_HEAD(&md5sig->head);
1348 rcu_assign_pointer(tp->md5sig_info, md5sig);
1349 return 0;
1350}
1351
1352/* This can be called on a newly created socket, from other files */
1353static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1354 int family, u8 prefixlen, int l3index, u8 flags,
1355 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1356{
1357 /* Add Key to the list */
1358 struct tcp_md5sig_key *key;
1359 struct tcp_sock *tp = tcp_sk(sk);
1360 struct tcp_md5sig_info *md5sig;
1361
1362 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1363 if (key) {
1364 /* Pre-existing entry - just update that one.
1365 * Note that the key might be used concurrently.
1366 * data_race() is telling kcsan that we do not care of
1367 * key mismatches, since changing MD5 key on live flows
1368 * can lead to packet drops.
1369 */
1370 data_race(memcpy(key->key, newkey, newkeylen));
1371
1372 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1373 * Also note that a reader could catch new key->keylen value
1374 * but old key->key[], this is the reason we use __GFP_ZERO
1375 * at sock_kmalloc() time below these lines.
1376 */
1377 WRITE_ONCE(key->keylen, newkeylen);
1378
1379 return 0;
1380 }
1381
1382 md5sig = rcu_dereference_protected(tp->md5sig_info,
1383 lockdep_sock_is_held(sk));
1384
1385 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1386 if (!key)
1387 return -ENOMEM;
1388
1389 memcpy(key->key, newkey, newkeylen);
1390 key->keylen = newkeylen;
1391 key->family = family;
1392 key->prefixlen = prefixlen;
1393 key->l3index = l3index;
1394 key->flags = flags;
1395 memcpy(&key->addr, addr,
1396 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1397 sizeof(struct in_addr));
1398 hlist_add_head_rcu(&key->node, &md5sig->head);
1399 return 0;
1400}
1401
1402int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1403 int family, u8 prefixlen, int l3index, u8 flags,
1404 const u8 *newkey, u8 newkeylen)
1405{
1406 struct tcp_sock *tp = tcp_sk(sk);
1407
1408 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1409 if (tcp_md5_alloc_sigpool())
1410 return -ENOMEM;
1411
1412 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1413 tcp_md5_release_sigpool();
1414 return -ENOMEM;
1415 }
1416
1417 if (!static_branch_inc(&tcp_md5_needed.key)) {
1418 struct tcp_md5sig_info *md5sig;
1419
1420 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1421 rcu_assign_pointer(tp->md5sig_info, NULL);
1422 kfree_rcu(md5sig, rcu);
1423 tcp_md5_release_sigpool();
1424 return -EUSERS;
1425 }
1426 }
1427
1428 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1429 newkey, newkeylen, GFP_KERNEL);
1430}
1431EXPORT_SYMBOL(tcp_md5_do_add);
1432
1433int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1434 int family, u8 prefixlen, int l3index,
1435 struct tcp_md5sig_key *key)
1436{
1437 struct tcp_sock *tp = tcp_sk(sk);
1438
1439 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1440 tcp_md5_add_sigpool();
1441
1442 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1443 tcp_md5_release_sigpool();
1444 return -ENOMEM;
1445 }
1446
1447 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1448 struct tcp_md5sig_info *md5sig;
1449
1450 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1451 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1452 rcu_assign_pointer(tp->md5sig_info, NULL);
1453 kfree_rcu(md5sig, rcu);
1454 tcp_md5_release_sigpool();
1455 return -EUSERS;
1456 }
1457 }
1458
1459 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1460 key->flags, key->key, key->keylen,
1461 sk_gfp_mask(sk, GFP_ATOMIC));
1462}
1463EXPORT_SYMBOL(tcp_md5_key_copy);
1464
1465int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1466 u8 prefixlen, int l3index, u8 flags)
1467{
1468 struct tcp_md5sig_key *key;
1469
1470 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1471 if (!key)
1472 return -ENOENT;
1473 hlist_del_rcu(&key->node);
1474 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1475 kfree_rcu(key, rcu);
1476 return 0;
1477}
1478EXPORT_SYMBOL(tcp_md5_do_del);
1479
1480void tcp_clear_md5_list(struct sock *sk)
1481{
1482 struct tcp_sock *tp = tcp_sk(sk);
1483 struct tcp_md5sig_key *key;
1484 struct hlist_node *n;
1485 struct tcp_md5sig_info *md5sig;
1486
1487 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1488
1489 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1490 hlist_del_rcu(&key->node);
1491 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1492 kfree_rcu(key, rcu);
1493 }
1494}
1495
1496static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1497 sockptr_t optval, int optlen)
1498{
1499 struct tcp_md5sig cmd;
1500 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1501 const union tcp_md5_addr *addr;
1502 u8 prefixlen = 32;
1503 int l3index = 0;
1504 bool l3flag;
1505 u8 flags;
1506
1507 if (optlen < sizeof(cmd))
1508 return -EINVAL;
1509
1510 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1511 return -EFAULT;
1512
1513 if (sin->sin_family != AF_INET)
1514 return -EINVAL;
1515
1516 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1517 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1518
1519 if (optname == TCP_MD5SIG_EXT &&
1520 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1521 prefixlen = cmd.tcpm_prefixlen;
1522 if (prefixlen > 32)
1523 return -EINVAL;
1524 }
1525
1526 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1527 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1528 struct net_device *dev;
1529
1530 rcu_read_lock();
1531 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1532 if (dev && netif_is_l3_master(dev))
1533 l3index = dev->ifindex;
1534
1535 rcu_read_unlock();
1536
1537 /* ok to reference set/not set outside of rcu;
1538 * right now device MUST be an L3 master
1539 */
1540 if (!dev || !l3index)
1541 return -EINVAL;
1542 }
1543
1544 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1545
1546 if (!cmd.tcpm_keylen)
1547 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1548
1549 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1550 return -EINVAL;
1551
1552 /* Don't allow keys for peers that have a matching TCP-AO key.
1553 * See the comment in tcp_ao_add_cmd()
1554 */
1555 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1556 return -EKEYREJECTED;
1557
1558 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1559 cmd.tcpm_key, cmd.tcpm_keylen);
1560}
1561
1562static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1563 __be32 daddr, __be32 saddr,
1564 const struct tcphdr *th, int nbytes)
1565{
1566 struct tcp4_pseudohdr *bp;
1567 struct scatterlist sg;
1568 struct tcphdr *_th;
1569
1570 bp = hp->scratch;
1571 bp->saddr = saddr;
1572 bp->daddr = daddr;
1573 bp->pad = 0;
1574 bp->protocol = IPPROTO_TCP;
1575 bp->len = cpu_to_be16(nbytes);
1576
1577 _th = (struct tcphdr *)(bp + 1);
1578 memcpy(_th, th, sizeof(*th));
1579 _th->check = 0;
1580
1581 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1582 ahash_request_set_crypt(hp->req, &sg, NULL,
1583 sizeof(*bp) + sizeof(*th));
1584 return crypto_ahash_update(hp->req);
1585}
1586
1587static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1588 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1589{
1590 struct tcp_sigpool hp;
1591
1592 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1593 goto clear_hash_nostart;
1594
1595 if (crypto_ahash_init(hp.req))
1596 goto clear_hash;
1597 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1598 goto clear_hash;
1599 if (tcp_md5_hash_key(&hp, key))
1600 goto clear_hash;
1601 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1602 if (crypto_ahash_final(hp.req))
1603 goto clear_hash;
1604
1605 tcp_sigpool_end(&hp);
1606 return 0;
1607
1608clear_hash:
1609 tcp_sigpool_end(&hp);
1610clear_hash_nostart:
1611 memset(md5_hash, 0, 16);
1612 return 1;
1613}
1614
1615int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1616 const struct sock *sk,
1617 const struct sk_buff *skb)
1618{
1619 const struct tcphdr *th = tcp_hdr(skb);
1620 struct tcp_sigpool hp;
1621 __be32 saddr, daddr;
1622
1623 if (sk) { /* valid for establish/request sockets */
1624 saddr = sk->sk_rcv_saddr;
1625 daddr = sk->sk_daddr;
1626 } else {
1627 const struct iphdr *iph = ip_hdr(skb);
1628 saddr = iph->saddr;
1629 daddr = iph->daddr;
1630 }
1631
1632 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1633 goto clear_hash_nostart;
1634
1635 if (crypto_ahash_init(hp.req))
1636 goto clear_hash;
1637
1638 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1639 goto clear_hash;
1640 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1641 goto clear_hash;
1642 if (tcp_md5_hash_key(&hp, key))
1643 goto clear_hash;
1644 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1645 if (crypto_ahash_final(hp.req))
1646 goto clear_hash;
1647
1648 tcp_sigpool_end(&hp);
1649 return 0;
1650
1651clear_hash:
1652 tcp_sigpool_end(&hp);
1653clear_hash_nostart:
1654 memset(md5_hash, 0, 16);
1655 return 1;
1656}
1657EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1658
1659#endif
1660
1661static void tcp_v4_init_req(struct request_sock *req,
1662 const struct sock *sk_listener,
1663 struct sk_buff *skb)
1664{
1665 struct inet_request_sock *ireq = inet_rsk(req);
1666 struct net *net = sock_net(sk_listener);
1667
1668 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1669 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1670 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1671}
1672
1673static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1674 struct sk_buff *skb,
1675 struct flowi *fl,
1676 struct request_sock *req)
1677{
1678 tcp_v4_init_req(req, sk, skb);
1679
1680 if (security_inet_conn_request(sk, skb, req))
1681 return NULL;
1682
1683 return inet_csk_route_req(sk, &fl->u.ip4, req);
1684}
1685
1686struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1687 .family = PF_INET,
1688 .obj_size = sizeof(struct tcp_request_sock),
1689 .rtx_syn_ack = tcp_rtx_synack,
1690 .send_ack = tcp_v4_reqsk_send_ack,
1691 .destructor = tcp_v4_reqsk_destructor,
1692 .send_reset = tcp_v4_send_reset,
1693 .syn_ack_timeout = tcp_syn_ack_timeout,
1694};
1695
1696const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1697 .mss_clamp = TCP_MSS_DEFAULT,
1698#ifdef CONFIG_TCP_MD5SIG
1699 .req_md5_lookup = tcp_v4_md5_lookup,
1700 .calc_md5_hash = tcp_v4_md5_hash_skb,
1701#endif
1702#ifdef CONFIG_TCP_AO
1703 .ao_lookup = tcp_v4_ao_lookup_rsk,
1704 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1705 .ao_synack_hash = tcp_v4_ao_synack_hash,
1706#endif
1707#ifdef CONFIG_SYN_COOKIES
1708 .cookie_init_seq = cookie_v4_init_sequence,
1709#endif
1710 .route_req = tcp_v4_route_req,
1711 .init_seq = tcp_v4_init_seq,
1712 .init_ts_off = tcp_v4_init_ts_off,
1713 .send_synack = tcp_v4_send_synack,
1714};
1715
1716int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1717{
1718 /* Never answer to SYNs send to broadcast or multicast */
1719 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1720 goto drop;
1721
1722 return tcp_conn_request(&tcp_request_sock_ops,
1723 &tcp_request_sock_ipv4_ops, sk, skb);
1724
1725drop:
1726 tcp_listendrop(sk);
1727 return 0;
1728}
1729EXPORT_SYMBOL(tcp_v4_conn_request);
1730
1731
1732/*
1733 * The three way handshake has completed - we got a valid synack -
1734 * now create the new socket.
1735 */
1736struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1737 struct request_sock *req,
1738 struct dst_entry *dst,
1739 struct request_sock *req_unhash,
1740 bool *own_req)
1741{
1742 struct inet_request_sock *ireq;
1743 bool found_dup_sk = false;
1744 struct inet_sock *newinet;
1745 struct tcp_sock *newtp;
1746 struct sock *newsk;
1747#ifdef CONFIG_TCP_MD5SIG
1748 const union tcp_md5_addr *addr;
1749 struct tcp_md5sig_key *key;
1750 int l3index;
1751#endif
1752 struct ip_options_rcu *inet_opt;
1753
1754 if (sk_acceptq_is_full(sk))
1755 goto exit_overflow;
1756
1757 newsk = tcp_create_openreq_child(sk, req, skb);
1758 if (!newsk)
1759 goto exit_nonewsk;
1760
1761 newsk->sk_gso_type = SKB_GSO_TCPV4;
1762 inet_sk_rx_dst_set(newsk, skb);
1763
1764 newtp = tcp_sk(newsk);
1765 newinet = inet_sk(newsk);
1766 ireq = inet_rsk(req);
1767 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1768 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1769 newsk->sk_bound_dev_if = ireq->ir_iif;
1770 newinet->inet_saddr = ireq->ir_loc_addr;
1771 inet_opt = rcu_dereference(ireq->ireq_opt);
1772 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1773 newinet->mc_index = inet_iif(skb);
1774 newinet->mc_ttl = ip_hdr(skb)->ttl;
1775 newinet->rcv_tos = ip_hdr(skb)->tos;
1776 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1777 if (inet_opt)
1778 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1779 atomic_set(&newinet->inet_id, get_random_u16());
1780
1781 /* Set ToS of the new socket based upon the value of incoming SYN.
1782 * ECT bits are set later in tcp_init_transfer().
1783 */
1784 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1785 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1786
1787 if (!dst) {
1788 dst = inet_csk_route_child_sock(sk, newsk, req);
1789 if (!dst)
1790 goto put_and_exit;
1791 } else {
1792 /* syncookie case : see end of cookie_v4_check() */
1793 }
1794 sk_setup_caps(newsk, dst);
1795
1796 tcp_ca_openreq_child(newsk, dst);
1797
1798 tcp_sync_mss(newsk, dst_mtu(dst));
1799 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1800
1801 tcp_initialize_rcv_mss(newsk);
1802
1803#ifdef CONFIG_TCP_MD5SIG
1804 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1805 /* Copy over the MD5 key from the original socket */
1806 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1807 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1808 if (key && !tcp_rsk_used_ao(req)) {
1809 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1810 goto put_and_exit;
1811 sk_gso_disable(newsk);
1812 }
1813#endif
1814#ifdef CONFIG_TCP_AO
1815 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1816 goto put_and_exit; /* OOM, release back memory */
1817#endif
1818
1819 if (__inet_inherit_port(sk, newsk) < 0)
1820 goto put_and_exit;
1821 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1822 &found_dup_sk);
1823 if (likely(*own_req)) {
1824 tcp_move_syn(newtp, req);
1825 ireq->ireq_opt = NULL;
1826 } else {
1827 newinet->inet_opt = NULL;
1828
1829 if (!req_unhash && found_dup_sk) {
1830 /* This code path should only be executed in the
1831 * syncookie case only
1832 */
1833 bh_unlock_sock(newsk);
1834 sock_put(newsk);
1835 newsk = NULL;
1836 }
1837 }
1838 return newsk;
1839
1840exit_overflow:
1841 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1842exit_nonewsk:
1843 dst_release(dst);
1844exit:
1845 tcp_listendrop(sk);
1846 return NULL;
1847put_and_exit:
1848 newinet->inet_opt = NULL;
1849 inet_csk_prepare_forced_close(newsk);
1850 tcp_done(newsk);
1851 goto exit;
1852}
1853EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1854
1855static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1856{
1857#ifdef CONFIG_SYN_COOKIES
1858 const struct tcphdr *th = tcp_hdr(skb);
1859
1860 if (!th->syn)
1861 sk = cookie_v4_check(sk, skb);
1862#endif
1863 return sk;
1864}
1865
1866u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1867 struct tcphdr *th, u32 *cookie)
1868{
1869 u16 mss = 0;
1870#ifdef CONFIG_SYN_COOKIES
1871 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1872 &tcp_request_sock_ipv4_ops, sk, th);
1873 if (mss) {
1874 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1875 tcp_synq_overflow(sk);
1876 }
1877#endif
1878 return mss;
1879}
1880
1881INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1882 u32));
1883/* The socket must have it's spinlock held when we get
1884 * here, unless it is a TCP_LISTEN socket.
1885 *
1886 * We have a potential double-lock case here, so even when
1887 * doing backlog processing we use the BH locking scheme.
1888 * This is because we cannot sleep with the original spinlock
1889 * held.
1890 */
1891int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1892{
1893 enum skb_drop_reason reason;
1894 struct sock *rsk;
1895
1896 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1897 struct dst_entry *dst;
1898
1899 dst = rcu_dereference_protected(sk->sk_rx_dst,
1900 lockdep_sock_is_held(sk));
1901
1902 sock_rps_save_rxhash(sk, skb);
1903 sk_mark_napi_id(sk, skb);
1904 if (dst) {
1905 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1906 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1907 dst, 0)) {
1908 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1909 dst_release(dst);
1910 }
1911 }
1912 tcp_rcv_established(sk, skb);
1913 return 0;
1914 }
1915
1916 if (tcp_checksum_complete(skb))
1917 goto csum_err;
1918
1919 if (sk->sk_state == TCP_LISTEN) {
1920 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1921
1922 if (!nsk)
1923 return 0;
1924 if (nsk != sk) {
1925 reason = tcp_child_process(sk, nsk, skb);
1926 if (reason) {
1927 rsk = nsk;
1928 goto reset;
1929 }
1930 return 0;
1931 }
1932 } else
1933 sock_rps_save_rxhash(sk, skb);
1934
1935 reason = tcp_rcv_state_process(sk, skb);
1936 if (reason) {
1937 rsk = sk;
1938 goto reset;
1939 }
1940 return 0;
1941
1942reset:
1943 tcp_v4_send_reset(rsk, skb);
1944discard:
1945 kfree_skb_reason(skb, reason);
1946 /* Be careful here. If this function gets more complicated and
1947 * gcc suffers from register pressure on the x86, sk (in %ebx)
1948 * might be destroyed here. This current version compiles correctly,
1949 * but you have been warned.
1950 */
1951 return 0;
1952
1953csum_err:
1954 reason = SKB_DROP_REASON_TCP_CSUM;
1955 trace_tcp_bad_csum(skb);
1956 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1957 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1958 goto discard;
1959}
1960EXPORT_SYMBOL(tcp_v4_do_rcv);
1961
1962int tcp_v4_early_demux(struct sk_buff *skb)
1963{
1964 struct net *net = dev_net(skb->dev);
1965 const struct iphdr *iph;
1966 const struct tcphdr *th;
1967 struct sock *sk;
1968
1969 if (skb->pkt_type != PACKET_HOST)
1970 return 0;
1971
1972 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1973 return 0;
1974
1975 iph = ip_hdr(skb);
1976 th = tcp_hdr(skb);
1977
1978 if (th->doff < sizeof(struct tcphdr) / 4)
1979 return 0;
1980
1981 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1982 iph->saddr, th->source,
1983 iph->daddr, ntohs(th->dest),
1984 skb->skb_iif, inet_sdif(skb));
1985 if (sk) {
1986 skb->sk = sk;
1987 skb->destructor = sock_edemux;
1988 if (sk_fullsock(sk)) {
1989 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1990
1991 if (dst)
1992 dst = dst_check(dst, 0);
1993 if (dst &&
1994 sk->sk_rx_dst_ifindex == skb->skb_iif)
1995 skb_dst_set_noref(skb, dst);
1996 }
1997 }
1998 return 0;
1999}
2000
2001bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
2002 enum skb_drop_reason *reason)
2003{
2004 u32 tail_gso_size, tail_gso_segs;
2005 struct skb_shared_info *shinfo;
2006 const struct tcphdr *th;
2007 struct tcphdr *thtail;
2008 struct sk_buff *tail;
2009 unsigned int hdrlen;
2010 bool fragstolen;
2011 u32 gso_segs;
2012 u32 gso_size;
2013 u64 limit;
2014 int delta;
2015
2016 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2017 * we can fix skb->truesize to its real value to avoid future drops.
2018 * This is valid because skb is not yet charged to the socket.
2019 * It has been noticed pure SACK packets were sometimes dropped
2020 * (if cooked by drivers without copybreak feature).
2021 */
2022 skb_condense(skb);
2023
2024 skb_dst_drop(skb);
2025
2026 if (unlikely(tcp_checksum_complete(skb))) {
2027 bh_unlock_sock(sk);
2028 trace_tcp_bad_csum(skb);
2029 *reason = SKB_DROP_REASON_TCP_CSUM;
2030 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2031 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2032 return true;
2033 }
2034
2035 /* Attempt coalescing to last skb in backlog, even if we are
2036 * above the limits.
2037 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2038 */
2039 th = (const struct tcphdr *)skb->data;
2040 hdrlen = th->doff * 4;
2041
2042 tail = sk->sk_backlog.tail;
2043 if (!tail)
2044 goto no_coalesce;
2045 thtail = (struct tcphdr *)tail->data;
2046
2047 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2048 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2049 ((TCP_SKB_CB(tail)->tcp_flags |
2050 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2051 !((TCP_SKB_CB(tail)->tcp_flags &
2052 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2053 ((TCP_SKB_CB(tail)->tcp_flags ^
2054 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2055#ifdef CONFIG_TLS_DEVICE
2056 tail->decrypted != skb->decrypted ||
2057#endif
2058 !mptcp_skb_can_collapse(tail, skb) ||
2059 thtail->doff != th->doff ||
2060 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2061 goto no_coalesce;
2062
2063 __skb_pull(skb, hdrlen);
2064
2065 shinfo = skb_shinfo(skb);
2066 gso_size = shinfo->gso_size ?: skb->len;
2067 gso_segs = shinfo->gso_segs ?: 1;
2068
2069 shinfo = skb_shinfo(tail);
2070 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2071 tail_gso_segs = shinfo->gso_segs ?: 1;
2072
2073 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2074 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2075
2076 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2077 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2078 thtail->window = th->window;
2079 }
2080
2081 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2082 * thtail->fin, so that the fast path in tcp_rcv_established()
2083 * is not entered if we append a packet with a FIN.
2084 * SYN, RST, URG are not present.
2085 * ACK is set on both packets.
2086 * PSH : we do not really care in TCP stack,
2087 * at least for 'GRO' packets.
2088 */
2089 thtail->fin |= th->fin;
2090 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2091
2092 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2093 TCP_SKB_CB(tail)->has_rxtstamp = true;
2094 tail->tstamp = skb->tstamp;
2095 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2096 }
2097
2098 /* Not as strict as GRO. We only need to carry mss max value */
2099 shinfo->gso_size = max(gso_size, tail_gso_size);
2100 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2101
2102 sk->sk_backlog.len += delta;
2103 __NET_INC_STATS(sock_net(sk),
2104 LINUX_MIB_TCPBACKLOGCOALESCE);
2105 kfree_skb_partial(skb, fragstolen);
2106 return false;
2107 }
2108 __skb_push(skb, hdrlen);
2109
2110no_coalesce:
2111 /* sk->sk_backlog.len is reset only at the end of __release_sock().
2112 * Both sk->sk_backlog.len and sk->sk_rmem_alloc could reach
2113 * sk_rcvbuf in normal conditions.
2114 */
2115 limit = ((u64)READ_ONCE(sk->sk_rcvbuf)) << 1;
2116
2117 limit += ((u32)READ_ONCE(sk->sk_sndbuf)) >> 1;
2118
2119 /* Only socket owner can try to collapse/prune rx queues
2120 * to reduce memory overhead, so add a little headroom here.
2121 * Few sockets backlog are possibly concurrently non empty.
2122 */
2123 limit += 64 * 1024;
2124
2125 limit = min_t(u64, limit, UINT_MAX);
2126
2127 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2128 bh_unlock_sock(sk);
2129 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2130 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2131 return true;
2132 }
2133 return false;
2134}
2135EXPORT_SYMBOL(tcp_add_backlog);
2136
2137int tcp_filter(struct sock *sk, struct sk_buff *skb)
2138{
2139 struct tcphdr *th = (struct tcphdr *)skb->data;
2140
2141 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2142}
2143EXPORT_SYMBOL(tcp_filter);
2144
2145static void tcp_v4_restore_cb(struct sk_buff *skb)
2146{
2147 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2148 sizeof(struct inet_skb_parm));
2149}
2150
2151static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2152 const struct tcphdr *th)
2153{
2154 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2155 * barrier() makes sure compiler wont play fool^Waliasing games.
2156 */
2157 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2158 sizeof(struct inet_skb_parm));
2159 barrier();
2160
2161 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2162 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2163 skb->len - th->doff * 4);
2164 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2165 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2166 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
2167 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2168 TCP_SKB_CB(skb)->sacked = 0;
2169 TCP_SKB_CB(skb)->has_rxtstamp =
2170 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2171}
2172
2173/*
2174 * From tcp_input.c
2175 */
2176
2177int tcp_v4_rcv(struct sk_buff *skb)
2178{
2179 struct net *net = dev_net(skb->dev);
2180 enum skb_drop_reason drop_reason;
2181 int sdif = inet_sdif(skb);
2182 int dif = inet_iif(skb);
2183 const struct iphdr *iph;
2184 const struct tcphdr *th;
2185 bool refcounted;
2186 struct sock *sk;
2187 int ret;
2188
2189 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2190 if (skb->pkt_type != PACKET_HOST)
2191 goto discard_it;
2192
2193 /* Count it even if it's bad */
2194 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2195
2196 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2197 goto discard_it;
2198
2199 th = (const struct tcphdr *)skb->data;
2200
2201 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2202 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2203 goto bad_packet;
2204 }
2205 if (!pskb_may_pull(skb, th->doff * 4))
2206 goto discard_it;
2207
2208 /* An explanation is required here, I think.
2209 * Packet length and doff are validated by header prediction,
2210 * provided case of th->doff==0 is eliminated.
2211 * So, we defer the checks. */
2212
2213 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2214 goto csum_error;
2215
2216 th = (const struct tcphdr *)skb->data;
2217 iph = ip_hdr(skb);
2218lookup:
2219 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2220 skb, __tcp_hdrlen(th), th->source,
2221 th->dest, sdif, &refcounted);
2222 if (!sk)
2223 goto no_tcp_socket;
2224
2225process:
2226 if (sk->sk_state == TCP_TIME_WAIT)
2227 goto do_time_wait;
2228
2229 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2230 struct request_sock *req = inet_reqsk(sk);
2231 bool req_stolen = false;
2232 struct sock *nsk;
2233
2234 sk = req->rsk_listener;
2235 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2236 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2237 else
2238 drop_reason = tcp_inbound_hash(sk, req, skb,
2239 &iph->saddr, &iph->daddr,
2240 AF_INET, dif, sdif);
2241 if (unlikely(drop_reason)) {
2242 sk_drops_add(sk, skb);
2243 reqsk_put(req);
2244 goto discard_it;
2245 }
2246 if (tcp_checksum_complete(skb)) {
2247 reqsk_put(req);
2248 goto csum_error;
2249 }
2250 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2251 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2252 if (!nsk) {
2253 inet_csk_reqsk_queue_drop_and_put(sk, req);
2254 goto lookup;
2255 }
2256 sk = nsk;
2257 /* reuseport_migrate_sock() has already held one sk_refcnt
2258 * before returning.
2259 */
2260 } else {
2261 /* We own a reference on the listener, increase it again
2262 * as we might lose it too soon.
2263 */
2264 sock_hold(sk);
2265 }
2266 refcounted = true;
2267 nsk = NULL;
2268 if (!tcp_filter(sk, skb)) {
2269 th = (const struct tcphdr *)skb->data;
2270 iph = ip_hdr(skb);
2271 tcp_v4_fill_cb(skb, iph, th);
2272 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2273 } else {
2274 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2275 }
2276 if (!nsk) {
2277 reqsk_put(req);
2278 if (req_stolen) {
2279 /* Another cpu got exclusive access to req
2280 * and created a full blown socket.
2281 * Try to feed this packet to this socket
2282 * instead of discarding it.
2283 */
2284 tcp_v4_restore_cb(skb);
2285 sock_put(sk);
2286 goto lookup;
2287 }
2288 goto discard_and_relse;
2289 }
2290 nf_reset_ct(skb);
2291 if (nsk == sk) {
2292 reqsk_put(req);
2293 tcp_v4_restore_cb(skb);
2294 } else {
2295 drop_reason = tcp_child_process(sk, nsk, skb);
2296 if (drop_reason) {
2297 tcp_v4_send_reset(nsk, skb);
2298 goto discard_and_relse;
2299 }
2300 sock_put(sk);
2301 return 0;
2302 }
2303 }
2304
2305 if (static_branch_unlikely(&ip4_min_ttl)) {
2306 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2307 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2308 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2309 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2310 goto discard_and_relse;
2311 }
2312 }
2313
2314 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2315 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2316 goto discard_and_relse;
2317 }
2318
2319 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2320 AF_INET, dif, sdif);
2321 if (drop_reason)
2322 goto discard_and_relse;
2323
2324 nf_reset_ct(skb);
2325
2326 if (tcp_filter(sk, skb)) {
2327 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2328 goto discard_and_relse;
2329 }
2330 th = (const struct tcphdr *)skb->data;
2331 iph = ip_hdr(skb);
2332 tcp_v4_fill_cb(skb, iph, th);
2333
2334 skb->dev = NULL;
2335
2336 if (sk->sk_state == TCP_LISTEN) {
2337 ret = tcp_v4_do_rcv(sk, skb);
2338 goto put_and_return;
2339 }
2340
2341 sk_incoming_cpu_update(sk);
2342
2343 bh_lock_sock_nested(sk);
2344 tcp_segs_in(tcp_sk(sk), skb);
2345 ret = 0;
2346 if (!sock_owned_by_user(sk)) {
2347 ret = tcp_v4_do_rcv(sk, skb);
2348 } else {
2349 if (tcp_add_backlog(sk, skb, &drop_reason))
2350 goto discard_and_relse;
2351 }
2352 bh_unlock_sock(sk);
2353
2354put_and_return:
2355 if (refcounted)
2356 sock_put(sk);
2357
2358 return ret;
2359
2360no_tcp_socket:
2361 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2362 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2363 goto discard_it;
2364
2365 tcp_v4_fill_cb(skb, iph, th);
2366
2367 if (tcp_checksum_complete(skb)) {
2368csum_error:
2369 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2370 trace_tcp_bad_csum(skb);
2371 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2372bad_packet:
2373 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2374 } else {
2375 tcp_v4_send_reset(NULL, skb);
2376 }
2377
2378discard_it:
2379 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2380 /* Discard frame. */
2381 kfree_skb_reason(skb, drop_reason);
2382 return 0;
2383
2384discard_and_relse:
2385 sk_drops_add(sk, skb);
2386 if (refcounted)
2387 sock_put(sk);
2388 goto discard_it;
2389
2390do_time_wait:
2391 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2392 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2393 inet_twsk_put(inet_twsk(sk));
2394 goto discard_it;
2395 }
2396
2397 tcp_v4_fill_cb(skb, iph, th);
2398
2399 if (tcp_checksum_complete(skb)) {
2400 inet_twsk_put(inet_twsk(sk));
2401 goto csum_error;
2402 }
2403 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2404 case TCP_TW_SYN: {
2405 struct sock *sk2 = inet_lookup_listener(net,
2406 net->ipv4.tcp_death_row.hashinfo,
2407 skb, __tcp_hdrlen(th),
2408 iph->saddr, th->source,
2409 iph->daddr, th->dest,
2410 inet_iif(skb),
2411 sdif);
2412 if (sk2) {
2413 inet_twsk_deschedule_put(inet_twsk(sk));
2414 sk = sk2;
2415 tcp_v4_restore_cb(skb);
2416 refcounted = false;
2417 goto process;
2418 }
2419 }
2420 /* to ACK */
2421 fallthrough;
2422 case TCP_TW_ACK:
2423 tcp_v4_timewait_ack(sk, skb);
2424 break;
2425 case TCP_TW_RST:
2426 tcp_v4_send_reset(sk, skb);
2427 inet_twsk_deschedule_put(inet_twsk(sk));
2428 goto discard_it;
2429 case TCP_TW_SUCCESS:;
2430 }
2431 goto discard_it;
2432}
2433
2434static struct timewait_sock_ops tcp_timewait_sock_ops = {
2435 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2436 .twsk_unique = tcp_twsk_unique,
2437 .twsk_destructor= tcp_twsk_destructor,
2438};
2439
2440void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2441{
2442 struct dst_entry *dst = skb_dst(skb);
2443
2444 if (dst && dst_hold_safe(dst)) {
2445 rcu_assign_pointer(sk->sk_rx_dst, dst);
2446 sk->sk_rx_dst_ifindex = skb->skb_iif;
2447 }
2448}
2449EXPORT_SYMBOL(inet_sk_rx_dst_set);
2450
2451const struct inet_connection_sock_af_ops ipv4_specific = {
2452 .queue_xmit = ip_queue_xmit,
2453 .send_check = tcp_v4_send_check,
2454 .rebuild_header = inet_sk_rebuild_header,
2455 .sk_rx_dst_set = inet_sk_rx_dst_set,
2456 .conn_request = tcp_v4_conn_request,
2457 .syn_recv_sock = tcp_v4_syn_recv_sock,
2458 .net_header_len = sizeof(struct iphdr),
2459 .setsockopt = ip_setsockopt,
2460 .getsockopt = ip_getsockopt,
2461 .addr2sockaddr = inet_csk_addr2sockaddr,
2462 .sockaddr_len = sizeof(struct sockaddr_in),
2463 .mtu_reduced = tcp_v4_mtu_reduced,
2464};
2465EXPORT_SYMBOL(ipv4_specific);
2466
2467#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2468static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2469#ifdef CONFIG_TCP_MD5SIG
2470 .md5_lookup = tcp_v4_md5_lookup,
2471 .calc_md5_hash = tcp_v4_md5_hash_skb,
2472 .md5_parse = tcp_v4_parse_md5_keys,
2473#endif
2474#ifdef CONFIG_TCP_AO
2475 .ao_lookup = tcp_v4_ao_lookup,
2476 .calc_ao_hash = tcp_v4_ao_hash_skb,
2477 .ao_parse = tcp_v4_parse_ao,
2478 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2479#endif
2480};
2481#endif
2482
2483/* NOTE: A lot of things set to zero explicitly by call to
2484 * sk_alloc() so need not be done here.
2485 */
2486static int tcp_v4_init_sock(struct sock *sk)
2487{
2488 struct inet_connection_sock *icsk = inet_csk(sk);
2489
2490 tcp_init_sock(sk);
2491
2492 icsk->icsk_af_ops = &ipv4_specific;
2493
2494#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2495 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2496#endif
2497
2498 return 0;
2499}
2500
2501#ifdef CONFIG_TCP_MD5SIG
2502static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2503{
2504 struct tcp_md5sig_info *md5sig;
2505
2506 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2507 kfree(md5sig);
2508 static_branch_slow_dec_deferred(&tcp_md5_needed);
2509 tcp_md5_release_sigpool();
2510}
2511#endif
2512
2513void tcp_v4_destroy_sock(struct sock *sk)
2514{
2515 struct tcp_sock *tp = tcp_sk(sk);
2516
2517 trace_tcp_destroy_sock(sk);
2518
2519 tcp_clear_xmit_timers(sk);
2520
2521 tcp_cleanup_congestion_control(sk);
2522
2523 tcp_cleanup_ulp(sk);
2524
2525 /* Cleanup up the write buffer. */
2526 tcp_write_queue_purge(sk);
2527
2528 /* Check if we want to disable active TFO */
2529 tcp_fastopen_active_disable_ofo_check(sk);
2530
2531 /* Cleans up our, hopefully empty, out_of_order_queue. */
2532 skb_rbtree_purge(&tp->out_of_order_queue);
2533
2534#ifdef CONFIG_TCP_MD5SIG
2535 /* Clean up the MD5 key list, if any */
2536 if (tp->md5sig_info) {
2537 struct tcp_md5sig_info *md5sig;
2538
2539 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2540 tcp_clear_md5_list(sk);
2541 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2542 rcu_assign_pointer(tp->md5sig_info, NULL);
2543 }
2544#endif
2545 tcp_ao_destroy_sock(sk, false);
2546
2547 /* Clean up a referenced TCP bind bucket. */
2548 if (inet_csk(sk)->icsk_bind_hash)
2549 inet_put_port(sk);
2550
2551 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2552
2553 /* If socket is aborted during connect operation */
2554 tcp_free_fastopen_req(tp);
2555 tcp_fastopen_destroy_cipher(sk);
2556 tcp_saved_syn_free(tp);
2557
2558 sk_sockets_allocated_dec(sk);
2559}
2560EXPORT_SYMBOL(tcp_v4_destroy_sock);
2561
2562#ifdef CONFIG_PROC_FS
2563/* Proc filesystem TCP sock list dumping. */
2564
2565static unsigned short seq_file_family(const struct seq_file *seq);
2566
2567static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2568{
2569 unsigned short family = seq_file_family(seq);
2570
2571 /* AF_UNSPEC is used as a match all */
2572 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2573 net_eq(sock_net(sk), seq_file_net(seq)));
2574}
2575
2576/* Find a non empty bucket (starting from st->bucket)
2577 * and return the first sk from it.
2578 */
2579static void *listening_get_first(struct seq_file *seq)
2580{
2581 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2582 struct tcp_iter_state *st = seq->private;
2583
2584 st->offset = 0;
2585 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2586 struct inet_listen_hashbucket *ilb2;
2587 struct hlist_nulls_node *node;
2588 struct sock *sk;
2589
2590 ilb2 = &hinfo->lhash2[st->bucket];
2591 if (hlist_nulls_empty(&ilb2->nulls_head))
2592 continue;
2593
2594 spin_lock(&ilb2->lock);
2595 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2596 if (seq_sk_match(seq, sk))
2597 return sk;
2598 }
2599 spin_unlock(&ilb2->lock);
2600 }
2601
2602 return NULL;
2603}
2604
2605/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2606 * If "cur" is the last one in the st->bucket,
2607 * call listening_get_first() to return the first sk of the next
2608 * non empty bucket.
2609 */
2610static void *listening_get_next(struct seq_file *seq, void *cur)
2611{
2612 struct tcp_iter_state *st = seq->private;
2613 struct inet_listen_hashbucket *ilb2;
2614 struct hlist_nulls_node *node;
2615 struct inet_hashinfo *hinfo;
2616 struct sock *sk = cur;
2617
2618 ++st->num;
2619 ++st->offset;
2620
2621 sk = sk_nulls_next(sk);
2622 sk_nulls_for_each_from(sk, node) {
2623 if (seq_sk_match(seq, sk))
2624 return sk;
2625 }
2626
2627 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2628 ilb2 = &hinfo->lhash2[st->bucket];
2629 spin_unlock(&ilb2->lock);
2630 ++st->bucket;
2631 return listening_get_first(seq);
2632}
2633
2634static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2635{
2636 struct tcp_iter_state *st = seq->private;
2637 void *rc;
2638
2639 st->bucket = 0;
2640 st->offset = 0;
2641 rc = listening_get_first(seq);
2642
2643 while (rc && *pos) {
2644 rc = listening_get_next(seq, rc);
2645 --*pos;
2646 }
2647 return rc;
2648}
2649
2650static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2651 const struct tcp_iter_state *st)
2652{
2653 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2654}
2655
2656/*
2657 * Get first established socket starting from bucket given in st->bucket.
2658 * If st->bucket is zero, the very first socket in the hash is returned.
2659 */
2660static void *established_get_first(struct seq_file *seq)
2661{
2662 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2663 struct tcp_iter_state *st = seq->private;
2664
2665 st->offset = 0;
2666 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2667 struct sock *sk;
2668 struct hlist_nulls_node *node;
2669 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2670
2671 cond_resched();
2672
2673 /* Lockless fast path for the common case of empty buckets */
2674 if (empty_bucket(hinfo, st))
2675 continue;
2676
2677 spin_lock_bh(lock);
2678 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2679 if (seq_sk_match(seq, sk))
2680 return sk;
2681 }
2682 spin_unlock_bh(lock);
2683 }
2684
2685 return NULL;
2686}
2687
2688static void *established_get_next(struct seq_file *seq, void *cur)
2689{
2690 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2691 struct tcp_iter_state *st = seq->private;
2692 struct hlist_nulls_node *node;
2693 struct sock *sk = cur;
2694
2695 ++st->num;
2696 ++st->offset;
2697
2698 sk = sk_nulls_next(sk);
2699
2700 sk_nulls_for_each_from(sk, node) {
2701 if (seq_sk_match(seq, sk))
2702 return sk;
2703 }
2704
2705 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2706 ++st->bucket;
2707 return established_get_first(seq);
2708}
2709
2710static void *established_get_idx(struct seq_file *seq, loff_t pos)
2711{
2712 struct tcp_iter_state *st = seq->private;
2713 void *rc;
2714
2715 st->bucket = 0;
2716 rc = established_get_first(seq);
2717
2718 while (rc && pos) {
2719 rc = established_get_next(seq, rc);
2720 --pos;
2721 }
2722 return rc;
2723}
2724
2725static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2726{
2727 void *rc;
2728 struct tcp_iter_state *st = seq->private;
2729
2730 st->state = TCP_SEQ_STATE_LISTENING;
2731 rc = listening_get_idx(seq, &pos);
2732
2733 if (!rc) {
2734 st->state = TCP_SEQ_STATE_ESTABLISHED;
2735 rc = established_get_idx(seq, pos);
2736 }
2737
2738 return rc;
2739}
2740
2741static void *tcp_seek_last_pos(struct seq_file *seq)
2742{
2743 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2744 struct tcp_iter_state *st = seq->private;
2745 int bucket = st->bucket;
2746 int offset = st->offset;
2747 int orig_num = st->num;
2748 void *rc = NULL;
2749
2750 switch (st->state) {
2751 case TCP_SEQ_STATE_LISTENING:
2752 if (st->bucket > hinfo->lhash2_mask)
2753 break;
2754 rc = listening_get_first(seq);
2755 while (offset-- && rc && bucket == st->bucket)
2756 rc = listening_get_next(seq, rc);
2757 if (rc)
2758 break;
2759 st->bucket = 0;
2760 st->state = TCP_SEQ_STATE_ESTABLISHED;
2761 fallthrough;
2762 case TCP_SEQ_STATE_ESTABLISHED:
2763 if (st->bucket > hinfo->ehash_mask)
2764 break;
2765 rc = established_get_first(seq);
2766 while (offset-- && rc && bucket == st->bucket)
2767 rc = established_get_next(seq, rc);
2768 }
2769
2770 st->num = orig_num;
2771
2772 return rc;
2773}
2774
2775void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2776{
2777 struct tcp_iter_state *st = seq->private;
2778 void *rc;
2779
2780 if (*pos && *pos == st->last_pos) {
2781 rc = tcp_seek_last_pos(seq);
2782 if (rc)
2783 goto out;
2784 }
2785
2786 st->state = TCP_SEQ_STATE_LISTENING;
2787 st->num = 0;
2788 st->bucket = 0;
2789 st->offset = 0;
2790 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2791
2792out:
2793 st->last_pos = *pos;
2794 return rc;
2795}
2796EXPORT_SYMBOL(tcp_seq_start);
2797
2798void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2799{
2800 struct tcp_iter_state *st = seq->private;
2801 void *rc = NULL;
2802
2803 if (v == SEQ_START_TOKEN) {
2804 rc = tcp_get_idx(seq, 0);
2805 goto out;
2806 }
2807
2808 switch (st->state) {
2809 case TCP_SEQ_STATE_LISTENING:
2810 rc = listening_get_next(seq, v);
2811 if (!rc) {
2812 st->state = TCP_SEQ_STATE_ESTABLISHED;
2813 st->bucket = 0;
2814 st->offset = 0;
2815 rc = established_get_first(seq);
2816 }
2817 break;
2818 case TCP_SEQ_STATE_ESTABLISHED:
2819 rc = established_get_next(seq, v);
2820 break;
2821 }
2822out:
2823 ++*pos;
2824 st->last_pos = *pos;
2825 return rc;
2826}
2827EXPORT_SYMBOL(tcp_seq_next);
2828
2829void tcp_seq_stop(struct seq_file *seq, void *v)
2830{
2831 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2832 struct tcp_iter_state *st = seq->private;
2833
2834 switch (st->state) {
2835 case TCP_SEQ_STATE_LISTENING:
2836 if (v != SEQ_START_TOKEN)
2837 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2838 break;
2839 case TCP_SEQ_STATE_ESTABLISHED:
2840 if (v)
2841 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2842 break;
2843 }
2844}
2845EXPORT_SYMBOL(tcp_seq_stop);
2846
2847static void get_openreq4(const struct request_sock *req,
2848 struct seq_file *f, int i)
2849{
2850 const struct inet_request_sock *ireq = inet_rsk(req);
2851 long delta = req->rsk_timer.expires - jiffies;
2852
2853 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2854 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2855 i,
2856 ireq->ir_loc_addr,
2857 ireq->ir_num,
2858 ireq->ir_rmt_addr,
2859 ntohs(ireq->ir_rmt_port),
2860 TCP_SYN_RECV,
2861 0, 0, /* could print option size, but that is af dependent. */
2862 1, /* timers active (only the expire timer) */
2863 jiffies_delta_to_clock_t(delta),
2864 req->num_timeout,
2865 from_kuid_munged(seq_user_ns(f),
2866 sock_i_uid(req->rsk_listener)),
2867 0, /* non standard timer */
2868 0, /* open_requests have no inode */
2869 0,
2870 req);
2871}
2872
2873static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2874{
2875 int timer_active;
2876 unsigned long timer_expires;
2877 const struct tcp_sock *tp = tcp_sk(sk);
2878 const struct inet_connection_sock *icsk = inet_csk(sk);
2879 const struct inet_sock *inet = inet_sk(sk);
2880 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2881 __be32 dest = inet->inet_daddr;
2882 __be32 src = inet->inet_rcv_saddr;
2883 __u16 destp = ntohs(inet->inet_dport);
2884 __u16 srcp = ntohs(inet->inet_sport);
2885 int rx_queue;
2886 int state;
2887
2888 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2889 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2890 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2891 timer_active = 1;
2892 timer_expires = icsk->icsk_timeout;
2893 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2894 timer_active = 4;
2895 timer_expires = icsk->icsk_timeout;
2896 } else if (timer_pending(&sk->sk_timer)) {
2897 timer_active = 2;
2898 timer_expires = sk->sk_timer.expires;
2899 } else {
2900 timer_active = 0;
2901 timer_expires = jiffies;
2902 }
2903
2904 state = inet_sk_state_load(sk);
2905 if (state == TCP_LISTEN)
2906 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2907 else
2908 /* Because we don't lock the socket,
2909 * we might find a transient negative value.
2910 */
2911 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2912 READ_ONCE(tp->copied_seq), 0);
2913
2914 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2915 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2916 i, src, srcp, dest, destp, state,
2917 READ_ONCE(tp->write_seq) - tp->snd_una,
2918 rx_queue,
2919 timer_active,
2920 jiffies_delta_to_clock_t(timer_expires - jiffies),
2921 icsk->icsk_retransmits,
2922 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2923 icsk->icsk_probes_out,
2924 sock_i_ino(sk),
2925 refcount_read(&sk->sk_refcnt), sk,
2926 jiffies_to_clock_t(icsk->icsk_rto),
2927 jiffies_to_clock_t(icsk->icsk_ack.ato),
2928 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2929 tcp_snd_cwnd(tp),
2930 state == TCP_LISTEN ?
2931 fastopenq->max_qlen :
2932 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2933}
2934
2935static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2936 struct seq_file *f, int i)
2937{
2938 long delta = tw->tw_timer.expires - jiffies;
2939 __be32 dest, src;
2940 __u16 destp, srcp;
2941
2942 dest = tw->tw_daddr;
2943 src = tw->tw_rcv_saddr;
2944 destp = ntohs(tw->tw_dport);
2945 srcp = ntohs(tw->tw_sport);
2946
2947 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2948 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2949 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2950 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2951 refcount_read(&tw->tw_refcnt), tw);
2952}
2953
2954#define TMPSZ 150
2955
2956static int tcp4_seq_show(struct seq_file *seq, void *v)
2957{
2958 struct tcp_iter_state *st;
2959 struct sock *sk = v;
2960
2961 seq_setwidth(seq, TMPSZ - 1);
2962 if (v == SEQ_START_TOKEN) {
2963 seq_puts(seq, " sl local_address rem_address st tx_queue "
2964 "rx_queue tr tm->when retrnsmt uid timeout "
2965 "inode");
2966 goto out;
2967 }
2968 st = seq->private;
2969
2970 if (sk->sk_state == TCP_TIME_WAIT)
2971 get_timewait4_sock(v, seq, st->num);
2972 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2973 get_openreq4(v, seq, st->num);
2974 else
2975 get_tcp4_sock(v, seq, st->num);
2976out:
2977 seq_pad(seq, '\n');
2978 return 0;
2979}
2980
2981#ifdef CONFIG_BPF_SYSCALL
2982struct bpf_tcp_iter_state {
2983 struct tcp_iter_state state;
2984 unsigned int cur_sk;
2985 unsigned int end_sk;
2986 unsigned int max_sk;
2987 struct sock **batch;
2988 bool st_bucket_done;
2989};
2990
2991struct bpf_iter__tcp {
2992 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2993 __bpf_md_ptr(struct sock_common *, sk_common);
2994 uid_t uid __aligned(8);
2995};
2996
2997static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2998 struct sock_common *sk_common, uid_t uid)
2999{
3000 struct bpf_iter__tcp ctx;
3001
3002 meta->seq_num--; /* skip SEQ_START_TOKEN */
3003 ctx.meta = meta;
3004 ctx.sk_common = sk_common;
3005 ctx.uid = uid;
3006 return bpf_iter_run_prog(prog, &ctx);
3007}
3008
3009static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
3010{
3011 while (iter->cur_sk < iter->end_sk)
3012 sock_gen_put(iter->batch[iter->cur_sk++]);
3013}
3014
3015static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
3016 unsigned int new_batch_sz)
3017{
3018 struct sock **new_batch;
3019
3020 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3021 GFP_USER | __GFP_NOWARN);
3022 if (!new_batch)
3023 return -ENOMEM;
3024
3025 bpf_iter_tcp_put_batch(iter);
3026 kvfree(iter->batch);
3027 iter->batch = new_batch;
3028 iter->max_sk = new_batch_sz;
3029
3030 return 0;
3031}
3032
3033static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3034 struct sock *start_sk)
3035{
3036 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3037 struct bpf_tcp_iter_state *iter = seq->private;
3038 struct tcp_iter_state *st = &iter->state;
3039 struct hlist_nulls_node *node;
3040 unsigned int expected = 1;
3041 struct sock *sk;
3042
3043 sock_hold(start_sk);
3044 iter->batch[iter->end_sk++] = start_sk;
3045
3046 sk = sk_nulls_next(start_sk);
3047 sk_nulls_for_each_from(sk, node) {
3048 if (seq_sk_match(seq, sk)) {
3049 if (iter->end_sk < iter->max_sk) {
3050 sock_hold(sk);
3051 iter->batch[iter->end_sk++] = sk;
3052 }
3053 expected++;
3054 }
3055 }
3056 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3057
3058 return expected;
3059}
3060
3061static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3062 struct sock *start_sk)
3063{
3064 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3065 struct bpf_tcp_iter_state *iter = seq->private;
3066 struct tcp_iter_state *st = &iter->state;
3067 struct hlist_nulls_node *node;
3068 unsigned int expected = 1;
3069 struct sock *sk;
3070
3071 sock_hold(start_sk);
3072 iter->batch[iter->end_sk++] = start_sk;
3073
3074 sk = sk_nulls_next(start_sk);
3075 sk_nulls_for_each_from(sk, node) {
3076 if (seq_sk_match(seq, sk)) {
3077 if (iter->end_sk < iter->max_sk) {
3078 sock_hold(sk);
3079 iter->batch[iter->end_sk++] = sk;
3080 }
3081 expected++;
3082 }
3083 }
3084 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3085
3086 return expected;
3087}
3088
3089static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3090{
3091 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3092 struct bpf_tcp_iter_state *iter = seq->private;
3093 struct tcp_iter_state *st = &iter->state;
3094 unsigned int expected;
3095 bool resized = false;
3096 struct sock *sk;
3097
3098 /* The st->bucket is done. Directly advance to the next
3099 * bucket instead of having the tcp_seek_last_pos() to skip
3100 * one by one in the current bucket and eventually find out
3101 * it has to advance to the next bucket.
3102 */
3103 if (iter->st_bucket_done) {
3104 st->offset = 0;
3105 st->bucket++;
3106 if (st->state == TCP_SEQ_STATE_LISTENING &&
3107 st->bucket > hinfo->lhash2_mask) {
3108 st->state = TCP_SEQ_STATE_ESTABLISHED;
3109 st->bucket = 0;
3110 }
3111 }
3112
3113again:
3114 /* Get a new batch */
3115 iter->cur_sk = 0;
3116 iter->end_sk = 0;
3117 iter->st_bucket_done = false;
3118
3119 sk = tcp_seek_last_pos(seq);
3120 if (!sk)
3121 return NULL; /* Done */
3122
3123 if (st->state == TCP_SEQ_STATE_LISTENING)
3124 expected = bpf_iter_tcp_listening_batch(seq, sk);
3125 else
3126 expected = bpf_iter_tcp_established_batch(seq, sk);
3127
3128 if (iter->end_sk == expected) {
3129 iter->st_bucket_done = true;
3130 return sk;
3131 }
3132
3133 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3134 resized = true;
3135 goto again;
3136 }
3137
3138 return sk;
3139}
3140
3141static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3142{
3143 /* bpf iter does not support lseek, so it always
3144 * continue from where it was stop()-ped.
3145 */
3146 if (*pos)
3147 return bpf_iter_tcp_batch(seq);
3148
3149 return SEQ_START_TOKEN;
3150}
3151
3152static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3153{
3154 struct bpf_tcp_iter_state *iter = seq->private;
3155 struct tcp_iter_state *st = &iter->state;
3156 struct sock *sk;
3157
3158 /* Whenever seq_next() is called, the iter->cur_sk is
3159 * done with seq_show(), so advance to the next sk in
3160 * the batch.
3161 */
3162 if (iter->cur_sk < iter->end_sk) {
3163 /* Keeping st->num consistent in tcp_iter_state.
3164 * bpf_iter_tcp does not use st->num.
3165 * meta.seq_num is used instead.
3166 */
3167 st->num++;
3168 /* Move st->offset to the next sk in the bucket such that
3169 * the future start() will resume at st->offset in
3170 * st->bucket. See tcp_seek_last_pos().
3171 */
3172 st->offset++;
3173 sock_gen_put(iter->batch[iter->cur_sk++]);
3174 }
3175
3176 if (iter->cur_sk < iter->end_sk)
3177 sk = iter->batch[iter->cur_sk];
3178 else
3179 sk = bpf_iter_tcp_batch(seq);
3180
3181 ++*pos;
3182 /* Keeping st->last_pos consistent in tcp_iter_state.
3183 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3184 */
3185 st->last_pos = *pos;
3186 return sk;
3187}
3188
3189static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3190{
3191 struct bpf_iter_meta meta;
3192 struct bpf_prog *prog;
3193 struct sock *sk = v;
3194 uid_t uid;
3195 int ret;
3196
3197 if (v == SEQ_START_TOKEN)
3198 return 0;
3199
3200 if (sk_fullsock(sk))
3201 lock_sock(sk);
3202
3203 if (unlikely(sk_unhashed(sk))) {
3204 ret = SEQ_SKIP;
3205 goto unlock;
3206 }
3207
3208 if (sk->sk_state == TCP_TIME_WAIT) {
3209 uid = 0;
3210 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3211 const struct request_sock *req = v;
3212
3213 uid = from_kuid_munged(seq_user_ns(seq),
3214 sock_i_uid(req->rsk_listener));
3215 } else {
3216 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3217 }
3218
3219 meta.seq = seq;
3220 prog = bpf_iter_get_info(&meta, false);
3221 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3222
3223unlock:
3224 if (sk_fullsock(sk))
3225 release_sock(sk);
3226 return ret;
3227
3228}
3229
3230static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3231{
3232 struct bpf_tcp_iter_state *iter = seq->private;
3233 struct bpf_iter_meta meta;
3234 struct bpf_prog *prog;
3235
3236 if (!v) {
3237 meta.seq = seq;
3238 prog = bpf_iter_get_info(&meta, true);
3239 if (prog)
3240 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3241 }
3242
3243 if (iter->cur_sk < iter->end_sk) {
3244 bpf_iter_tcp_put_batch(iter);
3245 iter->st_bucket_done = false;
3246 }
3247}
3248
3249static const struct seq_operations bpf_iter_tcp_seq_ops = {
3250 .show = bpf_iter_tcp_seq_show,
3251 .start = bpf_iter_tcp_seq_start,
3252 .next = bpf_iter_tcp_seq_next,
3253 .stop = bpf_iter_tcp_seq_stop,
3254};
3255#endif
3256static unsigned short seq_file_family(const struct seq_file *seq)
3257{
3258 const struct tcp_seq_afinfo *afinfo;
3259
3260#ifdef CONFIG_BPF_SYSCALL
3261 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3262 if (seq->op == &bpf_iter_tcp_seq_ops)
3263 return AF_UNSPEC;
3264#endif
3265
3266 /* Iterated from proc fs */
3267 afinfo = pde_data(file_inode(seq->file));
3268 return afinfo->family;
3269}
3270
3271static const struct seq_operations tcp4_seq_ops = {
3272 .show = tcp4_seq_show,
3273 .start = tcp_seq_start,
3274 .next = tcp_seq_next,
3275 .stop = tcp_seq_stop,
3276};
3277
3278static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3279 .family = AF_INET,
3280};
3281
3282static int __net_init tcp4_proc_init_net(struct net *net)
3283{
3284 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3285 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3286 return -ENOMEM;
3287 return 0;
3288}
3289
3290static void __net_exit tcp4_proc_exit_net(struct net *net)
3291{
3292 remove_proc_entry("tcp", net->proc_net);
3293}
3294
3295static struct pernet_operations tcp4_net_ops = {
3296 .init = tcp4_proc_init_net,
3297 .exit = tcp4_proc_exit_net,
3298};
3299
3300int __init tcp4_proc_init(void)
3301{
3302 return register_pernet_subsys(&tcp4_net_ops);
3303}
3304
3305void tcp4_proc_exit(void)
3306{
3307 unregister_pernet_subsys(&tcp4_net_ops);
3308}
3309#endif /* CONFIG_PROC_FS */
3310
3311/* @wake is one when sk_stream_write_space() calls us.
3312 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3313 * This mimics the strategy used in sock_def_write_space().
3314 */
3315bool tcp_stream_memory_free(const struct sock *sk, int wake)
3316{
3317 const struct tcp_sock *tp = tcp_sk(sk);
3318 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3319 READ_ONCE(tp->snd_nxt);
3320
3321 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3322}
3323EXPORT_SYMBOL(tcp_stream_memory_free);
3324
3325struct proto tcp_prot = {
3326 .name = "TCP",
3327 .owner = THIS_MODULE,
3328 .close = tcp_close,
3329 .pre_connect = tcp_v4_pre_connect,
3330 .connect = tcp_v4_connect,
3331 .disconnect = tcp_disconnect,
3332 .accept = inet_csk_accept,
3333 .ioctl = tcp_ioctl,
3334 .init = tcp_v4_init_sock,
3335 .destroy = tcp_v4_destroy_sock,
3336 .shutdown = tcp_shutdown,
3337 .setsockopt = tcp_setsockopt,
3338 .getsockopt = tcp_getsockopt,
3339 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3340 .keepalive = tcp_set_keepalive,
3341 .recvmsg = tcp_recvmsg,
3342 .sendmsg = tcp_sendmsg,
3343 .splice_eof = tcp_splice_eof,
3344 .backlog_rcv = tcp_v4_do_rcv,
3345 .release_cb = tcp_release_cb,
3346 .hash = inet_hash,
3347 .unhash = inet_unhash,
3348 .get_port = inet_csk_get_port,
3349 .put_port = inet_put_port,
3350#ifdef CONFIG_BPF_SYSCALL
3351 .psock_update_sk_prot = tcp_bpf_update_proto,
3352#endif
3353 .enter_memory_pressure = tcp_enter_memory_pressure,
3354 .leave_memory_pressure = tcp_leave_memory_pressure,
3355 .stream_memory_free = tcp_stream_memory_free,
3356 .sockets_allocated = &tcp_sockets_allocated,
3357 .orphan_count = &tcp_orphan_count,
3358
3359 .memory_allocated = &tcp_memory_allocated,
3360 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3361
3362 .memory_pressure = &tcp_memory_pressure,
3363 .sysctl_mem = sysctl_tcp_mem,
3364 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3365 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3366 .max_header = MAX_TCP_HEADER,
3367 .obj_size = sizeof(struct tcp_sock),
3368 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3369 .twsk_prot = &tcp_timewait_sock_ops,
3370 .rsk_prot = &tcp_request_sock_ops,
3371 .h.hashinfo = NULL,
3372 .no_autobind = true,
3373 .diag_destroy = tcp_abort,
3374};
3375EXPORT_SYMBOL(tcp_prot);
3376
3377static void __net_exit tcp_sk_exit(struct net *net)
3378{
3379 if (net->ipv4.tcp_congestion_control)
3380 bpf_module_put(net->ipv4.tcp_congestion_control,
3381 net->ipv4.tcp_congestion_control->owner);
3382}
3383
3384static void __net_init tcp_set_hashinfo(struct net *net)
3385{
3386 struct inet_hashinfo *hinfo;
3387 unsigned int ehash_entries;
3388 struct net *old_net;
3389
3390 if (net_eq(net, &init_net))
3391 goto fallback;
3392
3393 old_net = current->nsproxy->net_ns;
3394 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3395 if (!ehash_entries)
3396 goto fallback;
3397
3398 ehash_entries = roundup_pow_of_two(ehash_entries);
3399 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3400 if (!hinfo) {
3401 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3402 "for a netns, fallback to the global one\n",
3403 ehash_entries);
3404fallback:
3405 hinfo = &tcp_hashinfo;
3406 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3407 }
3408
3409 net->ipv4.tcp_death_row.hashinfo = hinfo;
3410 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3411 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3412}
3413
3414static int __net_init tcp_sk_init(struct net *net)
3415{
3416 net->ipv4.sysctl_tcp_ecn = 2;
3417 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3418
3419 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3420 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3421 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3422 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3423 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3424
3425 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3426 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3427 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3428
3429 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3430 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3431 net->ipv4.sysctl_tcp_syncookies = 1;
3432 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3433 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3434 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3435 net->ipv4.sysctl_tcp_orphan_retries = 0;
3436 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3437 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3438 net->ipv4.sysctl_tcp_tw_reuse = 2;
3439 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3440
3441 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3442 tcp_set_hashinfo(net);
3443
3444 net->ipv4.sysctl_tcp_sack = 1;
3445 net->ipv4.sysctl_tcp_window_scaling = 1;
3446 net->ipv4.sysctl_tcp_timestamps = 1;
3447 net->ipv4.sysctl_tcp_early_retrans = 3;
3448 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3449 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3450 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3451 net->ipv4.sysctl_tcp_max_reordering = 300;
3452 net->ipv4.sysctl_tcp_dsack = 1;
3453 net->ipv4.sysctl_tcp_app_win = 31;
3454 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3455 net->ipv4.sysctl_tcp_frto = 2;
3456 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3457 /* This limits the percentage of the congestion window which we
3458 * will allow a single TSO frame to consume. Building TSO frames
3459 * which are too large can cause TCP streams to be bursty.
3460 */
3461 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3462 /* Default TSQ limit of 16 TSO segments */
3463 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3464
3465 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3466 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3467
3468 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3469 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3470 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3471 net->ipv4.sysctl_tcp_autocorking = 1;
3472 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3473 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3474 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3475 if (net != &init_net) {
3476 memcpy(net->ipv4.sysctl_tcp_rmem,
3477 init_net.ipv4.sysctl_tcp_rmem,
3478 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3479 memcpy(net->ipv4.sysctl_tcp_wmem,
3480 init_net.ipv4.sysctl_tcp_wmem,
3481 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3482 }
3483 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3484 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3485 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3486 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3487 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3488 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3489 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3490
3491 /* Set default values for PLB */
3492 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3493 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3494 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3495 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3496 /* Default congestion threshold for PLB to mark a round is 50% */
3497 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3498
3499 /* Reno is always built in */
3500 if (!net_eq(net, &init_net) &&
3501 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3502 init_net.ipv4.tcp_congestion_control->owner))
3503 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3504 else
3505 net->ipv4.tcp_congestion_control = &tcp_reno;
3506
3507 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3508 net->ipv4.sysctl_tcp_shrink_window = 0;
3509
3510 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3511
3512 return 0;
3513}
3514
3515static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3516{
3517 struct net *net;
3518
3519 tcp_twsk_purge(net_exit_list, AF_INET);
3520
3521 list_for_each_entry(net, net_exit_list, exit_list) {
3522 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3523 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3524 tcp_fastopen_ctx_destroy(net);
3525 }
3526}
3527
3528static struct pernet_operations __net_initdata tcp_sk_ops = {
3529 .init = tcp_sk_init,
3530 .exit = tcp_sk_exit,
3531 .exit_batch = tcp_sk_exit_batch,
3532};
3533
3534#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3535DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3536 struct sock_common *sk_common, uid_t uid)
3537
3538#define INIT_BATCH_SZ 16
3539
3540static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3541{
3542 struct bpf_tcp_iter_state *iter = priv_data;
3543 int err;
3544
3545 err = bpf_iter_init_seq_net(priv_data, aux);
3546 if (err)
3547 return err;
3548
3549 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3550 if (err) {
3551 bpf_iter_fini_seq_net(priv_data);
3552 return err;
3553 }
3554
3555 return 0;
3556}
3557
3558static void bpf_iter_fini_tcp(void *priv_data)
3559{
3560 struct bpf_tcp_iter_state *iter = priv_data;
3561
3562 bpf_iter_fini_seq_net(priv_data);
3563 kvfree(iter->batch);
3564}
3565
3566static const struct bpf_iter_seq_info tcp_seq_info = {
3567 .seq_ops = &bpf_iter_tcp_seq_ops,
3568 .init_seq_private = bpf_iter_init_tcp,
3569 .fini_seq_private = bpf_iter_fini_tcp,
3570 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3571};
3572
3573static const struct bpf_func_proto *
3574bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3575 const struct bpf_prog *prog)
3576{
3577 switch (func_id) {
3578 case BPF_FUNC_setsockopt:
3579 return &bpf_sk_setsockopt_proto;
3580 case BPF_FUNC_getsockopt:
3581 return &bpf_sk_getsockopt_proto;
3582 default:
3583 return NULL;
3584 }
3585}
3586
3587static struct bpf_iter_reg tcp_reg_info = {
3588 .target = "tcp",
3589 .ctx_arg_info_size = 1,
3590 .ctx_arg_info = {
3591 { offsetof(struct bpf_iter__tcp, sk_common),
3592 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3593 },
3594 .get_func_proto = bpf_iter_tcp_get_func_proto,
3595 .seq_info = &tcp_seq_info,
3596};
3597
3598static void __init bpf_iter_register(void)
3599{
3600 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3601 if (bpf_iter_reg_target(&tcp_reg_info))
3602 pr_warn("Warning: could not register bpf iterator tcp\n");
3603}
3604
3605#endif
3606
3607void __init tcp_v4_init(void)
3608{
3609 int cpu, res;
3610
3611 for_each_possible_cpu(cpu) {
3612 struct sock *sk;
3613
3614 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3615 IPPROTO_TCP, &init_net);
3616 if (res)
3617 panic("Failed to create the TCP control socket.\n");
3618 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3619
3620 /* Please enforce IP_DF and IPID==0 for RST and
3621 * ACK sent in SYN-RECV and TIME-WAIT state.
3622 */
3623 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3624
3625 per_cpu(ipv4_tcp_sk, cpu) = sk;
3626 }
3627 if (register_pernet_subsys(&tcp_sk_ops))
3628 panic("Failed to create the TCP control socket.\n");
3629
3630#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3631 bpf_iter_register();
3632#endif
3633}