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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#include <net/rstreason.h>
74
75#include <linux/inet.h>
76#include <linux/ipv6.h>
77#include <linux/stddef.h>
78#include <linux/proc_fs.h>
79#include <linux/seq_file.h>
80#include <linux/inetdevice.h>
81#include <linux/btf_ids.h>
82#include <linux/skbuff_ref.h>
83
84#include <crypto/hash.h>
85#include <linux/scatterlist.h>
86
87#include <trace/events/tcp.h>
88
89#ifdef CONFIG_TCP_MD5SIG
90static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
91 __be32 daddr, __be32 saddr, const struct tcphdr *th);
92#endif
93
94struct inet_hashinfo tcp_hashinfo;
95EXPORT_SYMBOL(tcp_hashinfo);
96
97static DEFINE_PER_CPU(struct sock_bh_locked, ipv4_tcp_sk) = {
98 .bh_lock = INIT_LOCAL_LOCK(bh_lock),
99};
100
101static DEFINE_MUTEX(tcp_exit_batch_mutex);
102
103static u32 tcp_v4_init_seq(const struct sk_buff *skb)
104{
105 return secure_tcp_seq(ip_hdr(skb)->daddr,
106 ip_hdr(skb)->saddr,
107 tcp_hdr(skb)->dest,
108 tcp_hdr(skb)->source);
109}
110
111static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
112{
113 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
114}
115
116int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
117{
118 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
119 const struct inet_timewait_sock *tw = inet_twsk(sktw);
120 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
121 struct tcp_sock *tp = tcp_sk(sk);
122 int ts_recent_stamp;
123
124 if (READ_ONCE(tw->tw_substate) == TCP_FIN_WAIT2)
125 reuse = 0;
126
127 if (reuse == 2) {
128 /* Still does not detect *everything* that goes through
129 * lo, since we require a loopback src or dst address
130 * or direct binding to 'lo' interface.
131 */
132 bool loopback = false;
133 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
134 loopback = true;
135#if IS_ENABLED(CONFIG_IPV6)
136 if (tw->tw_family == AF_INET6) {
137 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
138 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
139 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
140 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
141 loopback = true;
142 } else
143#endif
144 {
145 if (ipv4_is_loopback(tw->tw_daddr) ||
146 ipv4_is_loopback(tw->tw_rcv_saddr))
147 loopback = true;
148 }
149 if (!loopback)
150 reuse = 0;
151 }
152
153 /* With PAWS, it is safe from the viewpoint
154 of data integrity. Even without PAWS it is safe provided sequence
155 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
156
157 Actually, the idea is close to VJ's one, only timestamp cache is
158 held not per host, but per port pair and TW bucket is used as state
159 holder.
160
161 If TW bucket has been already destroyed we fall back to VJ's scheme
162 and use initial timestamp retrieved from peer table.
163 */
164 ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
165 if (ts_recent_stamp &&
166 (!twp || (reuse && time_after32(ktime_get_seconds(),
167 ts_recent_stamp)))) {
168 /* inet_twsk_hashdance_schedule() sets sk_refcnt after putting twsk
169 * and releasing the bucket lock.
170 */
171 if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt)))
172 return 0;
173
174 /* In case of repair and re-using TIME-WAIT sockets we still
175 * want to be sure that it is safe as above but honor the
176 * sequence numbers and time stamps set as part of the repair
177 * process.
178 *
179 * Without this check re-using a TIME-WAIT socket with TCP
180 * repair would accumulate a -1 on the repair assigned
181 * sequence number. The first time it is reused the sequence
182 * is -1, the second time -2, etc. This fixes that issue
183 * without appearing to create any others.
184 */
185 if (likely(!tp->repair)) {
186 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
187
188 if (!seq)
189 seq = 1;
190 WRITE_ONCE(tp->write_seq, seq);
191 tp->rx_opt.ts_recent = READ_ONCE(tcptw->tw_ts_recent);
192 tp->rx_opt.ts_recent_stamp = ts_recent_stamp;
193 }
194
195 return 1;
196 }
197
198 return 0;
199}
200EXPORT_SYMBOL_GPL(tcp_twsk_unique);
201
202static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
203 int addr_len)
204{
205 /* This check is replicated from tcp_v4_connect() and intended to
206 * prevent BPF program called below from accessing bytes that are out
207 * of the bound specified by user in addr_len.
208 */
209 if (addr_len < sizeof(struct sockaddr_in))
210 return -EINVAL;
211
212 sock_owned_by_me(sk);
213
214 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
215}
216
217/* This will initiate an outgoing connection. */
218int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
219{
220 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
221 struct inet_timewait_death_row *tcp_death_row;
222 struct inet_sock *inet = inet_sk(sk);
223 struct tcp_sock *tp = tcp_sk(sk);
224 struct ip_options_rcu *inet_opt;
225 struct net *net = sock_net(sk);
226 __be16 orig_sport, orig_dport;
227 __be32 daddr, nexthop;
228 struct flowi4 *fl4;
229 struct rtable *rt;
230 int err;
231
232 if (addr_len < sizeof(struct sockaddr_in))
233 return -EINVAL;
234
235 if (usin->sin_family != AF_INET)
236 return -EAFNOSUPPORT;
237
238 nexthop = daddr = usin->sin_addr.s_addr;
239 inet_opt = rcu_dereference_protected(inet->inet_opt,
240 lockdep_sock_is_held(sk));
241 if (inet_opt && inet_opt->opt.srr) {
242 if (!daddr)
243 return -EINVAL;
244 nexthop = inet_opt->opt.faddr;
245 }
246
247 orig_sport = inet->inet_sport;
248 orig_dport = usin->sin_port;
249 fl4 = &inet->cork.fl.u.ip4;
250 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
251 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
252 orig_dport, sk);
253 if (IS_ERR(rt)) {
254 err = PTR_ERR(rt);
255 if (err == -ENETUNREACH)
256 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
257 return err;
258 }
259
260 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
261 ip_rt_put(rt);
262 return -ENETUNREACH;
263 }
264
265 if (!inet_opt || !inet_opt->opt.srr)
266 daddr = fl4->daddr;
267
268 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
269
270 if (!inet->inet_saddr) {
271 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
272 if (err) {
273 ip_rt_put(rt);
274 return err;
275 }
276 } else {
277 sk_rcv_saddr_set(sk, inet->inet_saddr);
278 }
279
280 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
281 /* Reset inherited state */
282 tp->rx_opt.ts_recent = 0;
283 tp->rx_opt.ts_recent_stamp = 0;
284 if (likely(!tp->repair))
285 WRITE_ONCE(tp->write_seq, 0);
286 }
287
288 inet->inet_dport = usin->sin_port;
289 sk_daddr_set(sk, daddr);
290
291 inet_csk(sk)->icsk_ext_hdr_len = 0;
292 if (inet_opt)
293 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
294
295 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
296
297 /* Socket identity is still unknown (sport may be zero).
298 * However we set state to SYN-SENT and not releasing socket
299 * lock select source port, enter ourselves into the hash tables and
300 * complete initialization after this.
301 */
302 tcp_set_state(sk, TCP_SYN_SENT);
303 err = inet_hash_connect(tcp_death_row, sk);
304 if (err)
305 goto failure;
306
307 sk_set_txhash(sk);
308
309 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
310 inet->inet_sport, inet->inet_dport, sk);
311 if (IS_ERR(rt)) {
312 err = PTR_ERR(rt);
313 rt = NULL;
314 goto failure;
315 }
316 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
317 /* OK, now commit destination to socket. */
318 sk->sk_gso_type = SKB_GSO_TCPV4;
319 sk_setup_caps(sk, &rt->dst);
320 rt = NULL;
321
322 if (likely(!tp->repair)) {
323 if (!tp->write_seq)
324 WRITE_ONCE(tp->write_seq,
325 secure_tcp_seq(inet->inet_saddr,
326 inet->inet_daddr,
327 inet->inet_sport,
328 usin->sin_port));
329 WRITE_ONCE(tp->tsoffset,
330 secure_tcp_ts_off(net, inet->inet_saddr,
331 inet->inet_daddr));
332 }
333
334 atomic_set(&inet->inet_id, get_random_u16());
335
336 if (tcp_fastopen_defer_connect(sk, &err))
337 return err;
338 if (err)
339 goto failure;
340
341 err = tcp_connect(sk);
342
343 if (err)
344 goto failure;
345
346 return 0;
347
348failure:
349 /*
350 * This unhashes the socket and releases the local port,
351 * if necessary.
352 */
353 tcp_set_state(sk, TCP_CLOSE);
354 inet_bhash2_reset_saddr(sk);
355 ip_rt_put(rt);
356 sk->sk_route_caps = 0;
357 inet->inet_dport = 0;
358 return err;
359}
360EXPORT_SYMBOL(tcp_v4_connect);
361
362/*
363 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
364 * It can be called through tcp_release_cb() if socket was owned by user
365 * at the time tcp_v4_err() was called to handle ICMP message.
366 */
367void tcp_v4_mtu_reduced(struct sock *sk)
368{
369 struct inet_sock *inet = inet_sk(sk);
370 struct dst_entry *dst;
371 u32 mtu;
372
373 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
374 return;
375 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
376 dst = inet_csk_update_pmtu(sk, mtu);
377 if (!dst)
378 return;
379
380 /* Something is about to be wrong... Remember soft error
381 * for the case, if this connection will not able to recover.
382 */
383 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
384 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
385
386 mtu = dst_mtu(dst);
387
388 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
389 ip_sk_accept_pmtu(sk) &&
390 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
391 tcp_sync_mss(sk, mtu);
392
393 /* Resend the TCP packet because it's
394 * clear that the old packet has been
395 * dropped. This is the new "fast" path mtu
396 * discovery.
397 */
398 tcp_simple_retransmit(sk);
399 } /* else let the usual retransmit timer handle it */
400}
401EXPORT_SYMBOL(tcp_v4_mtu_reduced);
402
403static void do_redirect(struct sk_buff *skb, struct sock *sk)
404{
405 struct dst_entry *dst = __sk_dst_check(sk, 0);
406
407 if (dst)
408 dst->ops->redirect(dst, sk, skb);
409}
410
411
412/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
413void tcp_req_err(struct sock *sk, u32 seq, bool abort)
414{
415 struct request_sock *req = inet_reqsk(sk);
416 struct net *net = sock_net(sk);
417
418 /* ICMPs are not backlogged, hence we cannot get
419 * an established socket here.
420 */
421 if (seq != tcp_rsk(req)->snt_isn) {
422 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
423 } else if (abort) {
424 /*
425 * Still in SYN_RECV, just remove it silently.
426 * There is no good way to pass the error to the newly
427 * created socket, and POSIX does not want network
428 * errors returned from accept().
429 */
430 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
431 tcp_listendrop(req->rsk_listener);
432 }
433 reqsk_put(req);
434}
435EXPORT_SYMBOL(tcp_req_err);
436
437/* TCP-LD (RFC 6069) logic */
438void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
439{
440 struct inet_connection_sock *icsk = inet_csk(sk);
441 struct tcp_sock *tp = tcp_sk(sk);
442 struct sk_buff *skb;
443 s32 remaining;
444 u32 delta_us;
445
446 if (sock_owned_by_user(sk))
447 return;
448
449 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
450 !icsk->icsk_backoff)
451 return;
452
453 skb = tcp_rtx_queue_head(sk);
454 if (WARN_ON_ONCE(!skb))
455 return;
456
457 icsk->icsk_backoff--;
458 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
459 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
460
461 tcp_mstamp_refresh(tp);
462 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
463 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
464
465 if (remaining > 0) {
466 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
467 remaining, TCP_RTO_MAX);
468 } else {
469 /* RTO revert clocked out retransmission.
470 * Will retransmit now.
471 */
472 tcp_retransmit_timer(sk);
473 }
474}
475EXPORT_SYMBOL(tcp_ld_RTO_revert);
476
477/*
478 * This routine is called by the ICMP module when it gets some
479 * sort of error condition. If err < 0 then the socket should
480 * be closed and the error returned to the user. If err > 0
481 * it's just the icmp type << 8 | icmp code. After adjustment
482 * header points to the first 8 bytes of the tcp header. We need
483 * to find the appropriate port.
484 *
485 * The locking strategy used here is very "optimistic". When
486 * someone else accesses the socket the ICMP is just dropped
487 * and for some paths there is no check at all.
488 * A more general error queue to queue errors for later handling
489 * is probably better.
490 *
491 */
492
493int tcp_v4_err(struct sk_buff *skb, u32 info)
494{
495 const struct iphdr *iph = (const struct iphdr *)skb->data;
496 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
497 struct tcp_sock *tp;
498 const int type = icmp_hdr(skb)->type;
499 const int code = icmp_hdr(skb)->code;
500 struct sock *sk;
501 struct request_sock *fastopen;
502 u32 seq, snd_una;
503 int err;
504 struct net *net = dev_net(skb->dev);
505
506 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
507 iph->daddr, th->dest, iph->saddr,
508 ntohs(th->source), inet_iif(skb), 0);
509 if (!sk) {
510 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
511 return -ENOENT;
512 }
513 if (sk->sk_state == TCP_TIME_WAIT) {
514 /* To increase the counter of ignored icmps for TCP-AO */
515 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
516 inet_twsk_put(inet_twsk(sk));
517 return 0;
518 }
519 seq = ntohl(th->seq);
520 if (sk->sk_state == TCP_NEW_SYN_RECV) {
521 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
522 type == ICMP_TIME_EXCEEDED ||
523 (type == ICMP_DEST_UNREACH &&
524 (code == ICMP_NET_UNREACH ||
525 code == ICMP_HOST_UNREACH)));
526 return 0;
527 }
528
529 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
530 sock_put(sk);
531 return 0;
532 }
533
534 bh_lock_sock(sk);
535 /* If too many ICMPs get dropped on busy
536 * servers this needs to be solved differently.
537 * We do take care of PMTU discovery (RFC1191) special case :
538 * we can receive locally generated ICMP messages while socket is held.
539 */
540 if (sock_owned_by_user(sk)) {
541 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
542 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
543 }
544 if (sk->sk_state == TCP_CLOSE)
545 goto out;
546
547 if (static_branch_unlikely(&ip4_min_ttl)) {
548 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
549 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
550 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
551 goto out;
552 }
553 }
554
555 tp = tcp_sk(sk);
556 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
557 fastopen = rcu_dereference(tp->fastopen_rsk);
558 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
559 if (sk->sk_state != TCP_LISTEN &&
560 !between(seq, snd_una, tp->snd_nxt)) {
561 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
562 goto out;
563 }
564
565 switch (type) {
566 case ICMP_REDIRECT:
567 if (!sock_owned_by_user(sk))
568 do_redirect(skb, sk);
569 goto out;
570 case ICMP_SOURCE_QUENCH:
571 /* Just silently ignore these. */
572 goto out;
573 case ICMP_PARAMETERPROB:
574 err = EPROTO;
575 break;
576 case ICMP_DEST_UNREACH:
577 if (code > NR_ICMP_UNREACH)
578 goto out;
579
580 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
581 /* We are not interested in TCP_LISTEN and open_requests
582 * (SYN-ACKs send out by Linux are always <576bytes so
583 * they should go through unfragmented).
584 */
585 if (sk->sk_state == TCP_LISTEN)
586 goto out;
587
588 WRITE_ONCE(tp->mtu_info, info);
589 if (!sock_owned_by_user(sk)) {
590 tcp_v4_mtu_reduced(sk);
591 } else {
592 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
593 sock_hold(sk);
594 }
595 goto out;
596 }
597
598 err = icmp_err_convert[code].errno;
599 /* check if this ICMP message allows revert of backoff.
600 * (see RFC 6069)
601 */
602 if (!fastopen &&
603 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
604 tcp_ld_RTO_revert(sk, seq);
605 break;
606 case ICMP_TIME_EXCEEDED:
607 err = EHOSTUNREACH;
608 break;
609 default:
610 goto out;
611 }
612
613 switch (sk->sk_state) {
614 case TCP_SYN_SENT:
615 case TCP_SYN_RECV:
616 /* Only in fast or simultaneous open. If a fast open socket is
617 * already accepted it is treated as a connected one below.
618 */
619 if (fastopen && !fastopen->sk)
620 break;
621
622 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
623
624 if (!sock_owned_by_user(sk))
625 tcp_done_with_error(sk, err);
626 else
627 WRITE_ONCE(sk->sk_err_soft, err);
628 goto out;
629 }
630
631 /* If we've already connected we will keep trying
632 * until we time out, or the user gives up.
633 *
634 * rfc1122 4.2.3.9 allows to consider as hard errors
635 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
636 * but it is obsoleted by pmtu discovery).
637 *
638 * Note, that in modern internet, where routing is unreliable
639 * and in each dark corner broken firewalls sit, sending random
640 * errors ordered by their masters even this two messages finally lose
641 * their original sense (even Linux sends invalid PORT_UNREACHs)
642 *
643 * Now we are in compliance with RFCs.
644 * --ANK (980905)
645 */
646
647 if (!sock_owned_by_user(sk) &&
648 inet_test_bit(RECVERR, sk)) {
649 WRITE_ONCE(sk->sk_err, err);
650 sk_error_report(sk);
651 } else { /* Only an error on timeout */
652 WRITE_ONCE(sk->sk_err_soft, err);
653 }
654
655out:
656 bh_unlock_sock(sk);
657 sock_put(sk);
658 return 0;
659}
660
661void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
662{
663 struct tcphdr *th = tcp_hdr(skb);
664
665 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
666 skb->csum_start = skb_transport_header(skb) - skb->head;
667 skb->csum_offset = offsetof(struct tcphdr, check);
668}
669
670/* This routine computes an IPv4 TCP checksum. */
671void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
672{
673 const struct inet_sock *inet = inet_sk(sk);
674
675 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
676}
677EXPORT_SYMBOL(tcp_v4_send_check);
678
679#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
680
681static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
682 const struct tcp_ao_hdr *aoh,
683 struct ip_reply_arg *arg, struct tcphdr *reply,
684 __be32 reply_options[REPLY_OPTIONS_LEN])
685{
686#ifdef CONFIG_TCP_AO
687 int sdif = tcp_v4_sdif(skb);
688 int dif = inet_iif(skb);
689 int l3index = sdif ? dif : 0;
690 bool allocated_traffic_key;
691 struct tcp_ao_key *key;
692 char *traffic_key;
693 bool drop = true;
694 u32 ao_sne = 0;
695 u8 keyid;
696
697 rcu_read_lock();
698 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
699 &key, &traffic_key, &allocated_traffic_key,
700 &keyid, &ao_sne))
701 goto out;
702
703 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
704 (aoh->rnext_keyid << 8) | keyid);
705 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
706 reply->doff = arg->iov[0].iov_len / 4;
707
708 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
709 key, traffic_key,
710 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
711 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
712 reply, ao_sne))
713 goto out;
714 drop = false;
715out:
716 rcu_read_unlock();
717 if (allocated_traffic_key)
718 kfree(traffic_key);
719 return drop;
720#else
721 return true;
722#endif
723}
724
725/*
726 * This routine will send an RST to the other tcp.
727 *
728 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
729 * for reset.
730 * Answer: if a packet caused RST, it is not for a socket
731 * existing in our system, if it is matched to a socket,
732 * it is just duplicate segment or bug in other side's TCP.
733 * So that we build reply only basing on parameters
734 * arrived with segment.
735 * Exception: precedence violation. We do not implement it in any case.
736 */
737
738static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
739 enum sk_rst_reason reason)
740{
741 const struct tcphdr *th = tcp_hdr(skb);
742 struct {
743 struct tcphdr th;
744 __be32 opt[REPLY_OPTIONS_LEN];
745 } rep;
746 const __u8 *md5_hash_location = NULL;
747 const struct tcp_ao_hdr *aoh;
748 struct ip_reply_arg arg;
749#ifdef CONFIG_TCP_MD5SIG
750 struct tcp_md5sig_key *key = NULL;
751 unsigned char newhash[16];
752 struct sock *sk1 = NULL;
753 int genhash;
754#endif
755 u64 transmit_time = 0;
756 struct sock *ctl_sk;
757 struct net *net;
758 u32 txhash = 0;
759
760 /* Never send a reset in response to a reset. */
761 if (th->rst)
762 return;
763
764 /* If sk not NULL, it means we did a successful lookup and incoming
765 * route had to be correct. prequeue might have dropped our dst.
766 */
767 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
768 return;
769
770 /* Swap the send and the receive. */
771 memset(&rep, 0, sizeof(rep));
772 rep.th.dest = th->source;
773 rep.th.source = th->dest;
774 rep.th.doff = sizeof(struct tcphdr) / 4;
775 rep.th.rst = 1;
776
777 if (th->ack) {
778 rep.th.seq = th->ack_seq;
779 } else {
780 rep.th.ack = 1;
781 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
782 skb->len - (th->doff << 2));
783 }
784
785 memset(&arg, 0, sizeof(arg));
786 arg.iov[0].iov_base = (unsigned char *)&rep;
787 arg.iov[0].iov_len = sizeof(rep.th);
788
789 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
790
791 /* Invalid TCP option size or twice included auth */
792 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
793 return;
794
795 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
796 return;
797
798#ifdef CONFIG_TCP_MD5SIG
799 rcu_read_lock();
800 if (sk && sk_fullsock(sk)) {
801 const union tcp_md5_addr *addr;
802 int l3index;
803
804 /* sdif set, means packet ingressed via a device
805 * in an L3 domain and inet_iif is set to it.
806 */
807 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
808 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
809 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
810 } else if (md5_hash_location) {
811 const union tcp_md5_addr *addr;
812 int sdif = tcp_v4_sdif(skb);
813 int dif = inet_iif(skb);
814 int l3index;
815
816 /*
817 * active side is lost. Try to find listening socket through
818 * source port, and then find md5 key through listening socket.
819 * we are not loose security here:
820 * Incoming packet is checked with md5 hash with finding key,
821 * no RST generated if md5 hash doesn't match.
822 */
823 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
824 NULL, 0, ip_hdr(skb)->saddr,
825 th->source, ip_hdr(skb)->daddr,
826 ntohs(th->source), dif, sdif);
827 /* don't send rst if it can't find key */
828 if (!sk1)
829 goto out;
830
831 /* sdif set, means packet ingressed via a device
832 * in an L3 domain and dif is set to it.
833 */
834 l3index = sdif ? dif : 0;
835 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
836 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
837 if (!key)
838 goto out;
839
840
841 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
842 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
843 goto out;
844
845 }
846
847 if (key) {
848 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
849 (TCPOPT_NOP << 16) |
850 (TCPOPT_MD5SIG << 8) |
851 TCPOLEN_MD5SIG);
852 /* Update length and the length the header thinks exists */
853 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
854 rep.th.doff = arg.iov[0].iov_len / 4;
855
856 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
857 key, ip_hdr(skb)->saddr,
858 ip_hdr(skb)->daddr, &rep.th);
859 }
860#endif
861 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
862 if (rep.opt[0] == 0) {
863 __be32 mrst = mptcp_reset_option(skb);
864
865 if (mrst) {
866 rep.opt[0] = mrst;
867 arg.iov[0].iov_len += sizeof(mrst);
868 rep.th.doff = arg.iov[0].iov_len / 4;
869 }
870 }
871
872 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
873 ip_hdr(skb)->saddr, /* XXX */
874 arg.iov[0].iov_len, IPPROTO_TCP, 0);
875 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
876 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
877
878 /* When socket is gone, all binding information is lost.
879 * routing might fail in this case. No choice here, if we choose to force
880 * input interface, we will misroute in case of asymmetric route.
881 */
882 if (sk)
883 arg.bound_dev_if = sk->sk_bound_dev_if;
884
885 trace_tcp_send_reset(sk, skb, reason);
886
887 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
888 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
889
890 arg.tos = ip_hdr(skb)->tos;
891 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
892 local_bh_disable();
893 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
894 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
895
896 sock_net_set(ctl_sk, net);
897 if (sk) {
898 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
899 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
900 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
901 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
902 transmit_time = tcp_transmit_time(sk);
903 xfrm_sk_clone_policy(ctl_sk, sk);
904 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
905 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
906 } else {
907 ctl_sk->sk_mark = 0;
908 ctl_sk->sk_priority = 0;
909 }
910 ip_send_unicast_reply(ctl_sk, sk,
911 skb, &TCP_SKB_CB(skb)->header.h4.opt,
912 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
913 &arg, arg.iov[0].iov_len,
914 transmit_time, txhash);
915
916 xfrm_sk_free_policy(ctl_sk);
917 sock_net_set(ctl_sk, &init_net);
918 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
919 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
920 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
921 local_bh_enable();
922
923#ifdef CONFIG_TCP_MD5SIG
924out:
925 rcu_read_unlock();
926#endif
927}
928
929/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
930 outside socket context is ugly, certainly. What can I do?
931 */
932
933static void tcp_v4_send_ack(const struct sock *sk,
934 struct sk_buff *skb, u32 seq, u32 ack,
935 u32 win, u32 tsval, u32 tsecr, int oif,
936 struct tcp_key *key,
937 int reply_flags, u8 tos, u32 txhash)
938{
939 const struct tcphdr *th = tcp_hdr(skb);
940 struct {
941 struct tcphdr th;
942 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
943 } rep;
944 struct net *net = sock_net(sk);
945 struct ip_reply_arg arg;
946 struct sock *ctl_sk;
947 u64 transmit_time;
948
949 memset(&rep.th, 0, sizeof(struct tcphdr));
950 memset(&arg, 0, sizeof(arg));
951
952 arg.iov[0].iov_base = (unsigned char *)&rep;
953 arg.iov[0].iov_len = sizeof(rep.th);
954 if (tsecr) {
955 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
956 (TCPOPT_TIMESTAMP << 8) |
957 TCPOLEN_TIMESTAMP);
958 rep.opt[1] = htonl(tsval);
959 rep.opt[2] = htonl(tsecr);
960 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
961 }
962
963 /* Swap the send and the receive. */
964 rep.th.dest = th->source;
965 rep.th.source = th->dest;
966 rep.th.doff = arg.iov[0].iov_len / 4;
967 rep.th.seq = htonl(seq);
968 rep.th.ack_seq = htonl(ack);
969 rep.th.ack = 1;
970 rep.th.window = htons(win);
971
972#ifdef CONFIG_TCP_MD5SIG
973 if (tcp_key_is_md5(key)) {
974 int offset = (tsecr) ? 3 : 0;
975
976 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
977 (TCPOPT_NOP << 16) |
978 (TCPOPT_MD5SIG << 8) |
979 TCPOLEN_MD5SIG);
980 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
981 rep.th.doff = arg.iov[0].iov_len/4;
982
983 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
984 key->md5_key, ip_hdr(skb)->saddr,
985 ip_hdr(skb)->daddr, &rep.th);
986 }
987#endif
988#ifdef CONFIG_TCP_AO
989 if (tcp_key_is_ao(key)) {
990 int offset = (tsecr) ? 3 : 0;
991
992 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
993 (tcp_ao_len(key->ao_key) << 16) |
994 (key->ao_key->sndid << 8) |
995 key->rcv_next);
996 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
997 rep.th.doff = arg.iov[0].iov_len / 4;
998
999 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
1000 key->ao_key, key->traffic_key,
1001 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
1002 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
1003 &rep.th, key->sne);
1004 }
1005#endif
1006 arg.flags = reply_flags;
1007 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
1008 ip_hdr(skb)->saddr, /* XXX */
1009 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1010 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1011 if (oif)
1012 arg.bound_dev_if = oif;
1013 arg.tos = tos;
1014 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1015 local_bh_disable();
1016 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
1017 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
1018 sock_net_set(ctl_sk, net);
1019 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1020 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1021 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1022 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1023 transmit_time = tcp_transmit_time(sk);
1024 ip_send_unicast_reply(ctl_sk, sk,
1025 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1026 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1027 &arg, arg.iov[0].iov_len,
1028 transmit_time, txhash);
1029
1030 sock_net_set(ctl_sk, &init_net);
1031 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1032 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
1033 local_bh_enable();
1034}
1035
1036static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1037{
1038 struct inet_timewait_sock *tw = inet_twsk(sk);
1039 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1040 struct tcp_key key = {};
1041#ifdef CONFIG_TCP_AO
1042 struct tcp_ao_info *ao_info;
1043
1044 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1045 /* FIXME: the segment to-be-acked is not verified yet */
1046 ao_info = rcu_dereference(tcptw->ao_info);
1047 if (ao_info) {
1048 const struct tcp_ao_hdr *aoh;
1049
1050 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1051 inet_twsk_put(tw);
1052 return;
1053 }
1054
1055 if (aoh)
1056 key.ao_key = tcp_ao_established_key(sk, ao_info,
1057 aoh->rnext_keyid, -1);
1058 }
1059 }
1060 if (key.ao_key) {
1061 struct tcp_ao_key *rnext_key;
1062
1063 key.traffic_key = snd_other_key(key.ao_key);
1064 key.sne = READ_ONCE(ao_info->snd_sne);
1065 rnext_key = READ_ONCE(ao_info->rnext_key);
1066 key.rcv_next = rnext_key->rcvid;
1067 key.type = TCP_KEY_AO;
1068#else
1069 if (0) {
1070#endif
1071 } else if (static_branch_tcp_md5()) {
1072 key.md5_key = tcp_twsk_md5_key(tcptw);
1073 if (key.md5_key)
1074 key.type = TCP_KEY_MD5;
1075 }
1076
1077 tcp_v4_send_ack(sk, skb,
1078 tcptw->tw_snd_nxt, READ_ONCE(tcptw->tw_rcv_nxt),
1079 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1080 tcp_tw_tsval(tcptw),
1081 READ_ONCE(tcptw->tw_ts_recent),
1082 tw->tw_bound_dev_if, &key,
1083 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1084 tw->tw_tos,
1085 tw->tw_txhash);
1086
1087 inet_twsk_put(tw);
1088}
1089
1090static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1091 struct request_sock *req)
1092{
1093 struct tcp_key key = {};
1094
1095 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1096 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1097 */
1098 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1099 tcp_sk(sk)->snd_nxt;
1100
1101#ifdef CONFIG_TCP_AO
1102 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1103 tcp_rsk_used_ao(req)) {
1104 const union tcp_md5_addr *addr;
1105 const struct tcp_ao_hdr *aoh;
1106 int l3index;
1107
1108 /* Invalid TCP option size or twice included auth */
1109 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1110 return;
1111 if (!aoh)
1112 return;
1113
1114 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1115 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1116 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1117 aoh->rnext_keyid, -1);
1118 if (unlikely(!key.ao_key)) {
1119 /* Send ACK with any matching MKT for the peer */
1120 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1121 /* Matching key disappeared (user removed the key?)
1122 * let the handshake timeout.
1123 */
1124 if (!key.ao_key) {
1125 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1126 addr,
1127 ntohs(tcp_hdr(skb)->source),
1128 &ip_hdr(skb)->daddr,
1129 ntohs(tcp_hdr(skb)->dest));
1130 return;
1131 }
1132 }
1133 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1134 if (!key.traffic_key)
1135 return;
1136
1137 key.type = TCP_KEY_AO;
1138 key.rcv_next = aoh->keyid;
1139 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1140#else
1141 if (0) {
1142#endif
1143 } else if (static_branch_tcp_md5()) {
1144 const union tcp_md5_addr *addr;
1145 int l3index;
1146
1147 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1148 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1149 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1150 if (key.md5_key)
1151 key.type = TCP_KEY_MD5;
1152 }
1153
1154 tcp_v4_send_ack(sk, skb, seq,
1155 tcp_rsk(req)->rcv_nxt,
1156 tcp_synack_window(req) >> inet_rsk(req)->rcv_wscale,
1157 tcp_rsk_tsval(tcp_rsk(req)),
1158 READ_ONCE(req->ts_recent),
1159 0, &key,
1160 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1161 ip_hdr(skb)->tos,
1162 READ_ONCE(tcp_rsk(req)->txhash));
1163 if (tcp_key_is_ao(&key))
1164 kfree(key.traffic_key);
1165}
1166
1167/*
1168 * Send a SYN-ACK after having received a SYN.
1169 * This still operates on a request_sock only, not on a big
1170 * socket.
1171 */
1172static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1173 struct flowi *fl,
1174 struct request_sock *req,
1175 struct tcp_fastopen_cookie *foc,
1176 enum tcp_synack_type synack_type,
1177 struct sk_buff *syn_skb)
1178{
1179 const struct inet_request_sock *ireq = inet_rsk(req);
1180 struct flowi4 fl4;
1181 int err = -1;
1182 struct sk_buff *skb;
1183 u8 tos;
1184
1185 /* First, grab a route. */
1186 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1187 return -1;
1188
1189 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1190
1191 if (skb) {
1192 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1193
1194 tos = READ_ONCE(inet_sk(sk)->tos);
1195
1196 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1197 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1198 (tos & INET_ECN_MASK);
1199
1200 if (!INET_ECN_is_capable(tos) &&
1201 tcp_bpf_ca_needs_ecn((struct sock *)req))
1202 tos |= INET_ECN_ECT_0;
1203
1204 rcu_read_lock();
1205 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1206 ireq->ir_rmt_addr,
1207 rcu_dereference(ireq->ireq_opt),
1208 tos);
1209 rcu_read_unlock();
1210 err = net_xmit_eval(err);
1211 }
1212
1213 return err;
1214}
1215
1216/*
1217 * IPv4 request_sock destructor.
1218 */
1219static void tcp_v4_reqsk_destructor(struct request_sock *req)
1220{
1221 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1222}
1223
1224#ifdef CONFIG_TCP_MD5SIG
1225/*
1226 * RFC2385 MD5 checksumming requires a mapping of
1227 * IP address->MD5 Key.
1228 * We need to maintain these in the sk structure.
1229 */
1230
1231DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1232EXPORT_SYMBOL(tcp_md5_needed);
1233
1234static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1235{
1236 if (!old)
1237 return true;
1238
1239 /* l3index always overrides non-l3index */
1240 if (old->l3index && new->l3index == 0)
1241 return false;
1242 if (old->l3index == 0 && new->l3index)
1243 return true;
1244
1245 return old->prefixlen < new->prefixlen;
1246}
1247
1248/* Find the Key structure for an address. */
1249struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1250 const union tcp_md5_addr *addr,
1251 int family, bool any_l3index)
1252{
1253 const struct tcp_sock *tp = tcp_sk(sk);
1254 struct tcp_md5sig_key *key;
1255 const struct tcp_md5sig_info *md5sig;
1256 __be32 mask;
1257 struct tcp_md5sig_key *best_match = NULL;
1258 bool match;
1259
1260 /* caller either holds rcu_read_lock() or socket lock */
1261 md5sig = rcu_dereference_check(tp->md5sig_info,
1262 lockdep_sock_is_held(sk));
1263 if (!md5sig)
1264 return NULL;
1265
1266 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1267 lockdep_sock_is_held(sk)) {
1268 if (key->family != family)
1269 continue;
1270 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1271 key->l3index != l3index)
1272 continue;
1273 if (family == AF_INET) {
1274 mask = inet_make_mask(key->prefixlen);
1275 match = (key->addr.a4.s_addr & mask) ==
1276 (addr->a4.s_addr & mask);
1277#if IS_ENABLED(CONFIG_IPV6)
1278 } else if (family == AF_INET6) {
1279 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1280 key->prefixlen);
1281#endif
1282 } else {
1283 match = false;
1284 }
1285
1286 if (match && better_md5_match(best_match, key))
1287 best_match = key;
1288 }
1289 return best_match;
1290}
1291EXPORT_SYMBOL(__tcp_md5_do_lookup);
1292
1293static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1294 const union tcp_md5_addr *addr,
1295 int family, u8 prefixlen,
1296 int l3index, u8 flags)
1297{
1298 const struct tcp_sock *tp = tcp_sk(sk);
1299 struct tcp_md5sig_key *key;
1300 unsigned int size = sizeof(struct in_addr);
1301 const struct tcp_md5sig_info *md5sig;
1302
1303 /* caller either holds rcu_read_lock() or socket lock */
1304 md5sig = rcu_dereference_check(tp->md5sig_info,
1305 lockdep_sock_is_held(sk));
1306 if (!md5sig)
1307 return NULL;
1308#if IS_ENABLED(CONFIG_IPV6)
1309 if (family == AF_INET6)
1310 size = sizeof(struct in6_addr);
1311#endif
1312 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1313 lockdep_sock_is_held(sk)) {
1314 if (key->family != family)
1315 continue;
1316 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1317 continue;
1318 if (key->l3index != l3index)
1319 continue;
1320 if (!memcmp(&key->addr, addr, size) &&
1321 key->prefixlen == prefixlen)
1322 return key;
1323 }
1324 return NULL;
1325}
1326
1327struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1328 const struct sock *addr_sk)
1329{
1330 const union tcp_md5_addr *addr;
1331 int l3index;
1332
1333 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1334 addr_sk->sk_bound_dev_if);
1335 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1336 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1337}
1338EXPORT_SYMBOL(tcp_v4_md5_lookup);
1339
1340static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1341{
1342 struct tcp_sock *tp = tcp_sk(sk);
1343 struct tcp_md5sig_info *md5sig;
1344
1345 md5sig = kmalloc(sizeof(*md5sig), gfp);
1346 if (!md5sig)
1347 return -ENOMEM;
1348
1349 sk_gso_disable(sk);
1350 INIT_HLIST_HEAD(&md5sig->head);
1351 rcu_assign_pointer(tp->md5sig_info, md5sig);
1352 return 0;
1353}
1354
1355/* This can be called on a newly created socket, from other files */
1356static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1357 int family, u8 prefixlen, int l3index, u8 flags,
1358 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1359{
1360 /* Add Key to the list */
1361 struct tcp_md5sig_key *key;
1362 struct tcp_sock *tp = tcp_sk(sk);
1363 struct tcp_md5sig_info *md5sig;
1364
1365 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1366 if (key) {
1367 /* Pre-existing entry - just update that one.
1368 * Note that the key might be used concurrently.
1369 * data_race() is telling kcsan that we do not care of
1370 * key mismatches, since changing MD5 key on live flows
1371 * can lead to packet drops.
1372 */
1373 data_race(memcpy(key->key, newkey, newkeylen));
1374
1375 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1376 * Also note that a reader could catch new key->keylen value
1377 * but old key->key[], this is the reason we use __GFP_ZERO
1378 * at sock_kmalloc() time below these lines.
1379 */
1380 WRITE_ONCE(key->keylen, newkeylen);
1381
1382 return 0;
1383 }
1384
1385 md5sig = rcu_dereference_protected(tp->md5sig_info,
1386 lockdep_sock_is_held(sk));
1387
1388 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1389 if (!key)
1390 return -ENOMEM;
1391
1392 memcpy(key->key, newkey, newkeylen);
1393 key->keylen = newkeylen;
1394 key->family = family;
1395 key->prefixlen = prefixlen;
1396 key->l3index = l3index;
1397 key->flags = flags;
1398 memcpy(&key->addr, addr,
1399 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1400 sizeof(struct in_addr));
1401 hlist_add_head_rcu(&key->node, &md5sig->head);
1402 return 0;
1403}
1404
1405int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1406 int family, u8 prefixlen, int l3index, u8 flags,
1407 const u8 *newkey, u8 newkeylen)
1408{
1409 struct tcp_sock *tp = tcp_sk(sk);
1410
1411 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1412 if (tcp_md5_alloc_sigpool())
1413 return -ENOMEM;
1414
1415 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1416 tcp_md5_release_sigpool();
1417 return -ENOMEM;
1418 }
1419
1420 if (!static_branch_inc(&tcp_md5_needed.key)) {
1421 struct tcp_md5sig_info *md5sig;
1422
1423 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1424 rcu_assign_pointer(tp->md5sig_info, NULL);
1425 kfree_rcu(md5sig, rcu);
1426 tcp_md5_release_sigpool();
1427 return -EUSERS;
1428 }
1429 }
1430
1431 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1432 newkey, newkeylen, GFP_KERNEL);
1433}
1434EXPORT_SYMBOL(tcp_md5_do_add);
1435
1436int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1437 int family, u8 prefixlen, int l3index,
1438 struct tcp_md5sig_key *key)
1439{
1440 struct tcp_sock *tp = tcp_sk(sk);
1441
1442 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1443 tcp_md5_add_sigpool();
1444
1445 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1446 tcp_md5_release_sigpool();
1447 return -ENOMEM;
1448 }
1449
1450 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1451 struct tcp_md5sig_info *md5sig;
1452
1453 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1454 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1455 rcu_assign_pointer(tp->md5sig_info, NULL);
1456 kfree_rcu(md5sig, rcu);
1457 tcp_md5_release_sigpool();
1458 return -EUSERS;
1459 }
1460 }
1461
1462 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1463 key->flags, key->key, key->keylen,
1464 sk_gfp_mask(sk, GFP_ATOMIC));
1465}
1466EXPORT_SYMBOL(tcp_md5_key_copy);
1467
1468int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1469 u8 prefixlen, int l3index, u8 flags)
1470{
1471 struct tcp_md5sig_key *key;
1472
1473 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1474 if (!key)
1475 return -ENOENT;
1476 hlist_del_rcu(&key->node);
1477 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1478 kfree_rcu(key, rcu);
1479 return 0;
1480}
1481EXPORT_SYMBOL(tcp_md5_do_del);
1482
1483void tcp_clear_md5_list(struct sock *sk)
1484{
1485 struct tcp_sock *tp = tcp_sk(sk);
1486 struct tcp_md5sig_key *key;
1487 struct hlist_node *n;
1488 struct tcp_md5sig_info *md5sig;
1489
1490 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1491
1492 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1493 hlist_del_rcu(&key->node);
1494 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1495 kfree_rcu(key, rcu);
1496 }
1497}
1498
1499static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1500 sockptr_t optval, int optlen)
1501{
1502 struct tcp_md5sig cmd;
1503 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1504 const union tcp_md5_addr *addr;
1505 u8 prefixlen = 32;
1506 int l3index = 0;
1507 bool l3flag;
1508 u8 flags;
1509
1510 if (optlen < sizeof(cmd))
1511 return -EINVAL;
1512
1513 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1514 return -EFAULT;
1515
1516 if (sin->sin_family != AF_INET)
1517 return -EINVAL;
1518
1519 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1520 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1521
1522 if (optname == TCP_MD5SIG_EXT &&
1523 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1524 prefixlen = cmd.tcpm_prefixlen;
1525 if (prefixlen > 32)
1526 return -EINVAL;
1527 }
1528
1529 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1530 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1531 struct net_device *dev;
1532
1533 rcu_read_lock();
1534 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1535 if (dev && netif_is_l3_master(dev))
1536 l3index = dev->ifindex;
1537
1538 rcu_read_unlock();
1539
1540 /* ok to reference set/not set outside of rcu;
1541 * right now device MUST be an L3 master
1542 */
1543 if (!dev || !l3index)
1544 return -EINVAL;
1545 }
1546
1547 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1548
1549 if (!cmd.tcpm_keylen)
1550 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1551
1552 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1553 return -EINVAL;
1554
1555 /* Don't allow keys for peers that have a matching TCP-AO key.
1556 * See the comment in tcp_ao_add_cmd()
1557 */
1558 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1559 return -EKEYREJECTED;
1560
1561 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1562 cmd.tcpm_key, cmd.tcpm_keylen);
1563}
1564
1565static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1566 __be32 daddr, __be32 saddr,
1567 const struct tcphdr *th, int nbytes)
1568{
1569 struct tcp4_pseudohdr *bp;
1570 struct scatterlist sg;
1571 struct tcphdr *_th;
1572
1573 bp = hp->scratch;
1574 bp->saddr = saddr;
1575 bp->daddr = daddr;
1576 bp->pad = 0;
1577 bp->protocol = IPPROTO_TCP;
1578 bp->len = cpu_to_be16(nbytes);
1579
1580 _th = (struct tcphdr *)(bp + 1);
1581 memcpy(_th, th, sizeof(*th));
1582 _th->check = 0;
1583
1584 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1585 ahash_request_set_crypt(hp->req, &sg, NULL,
1586 sizeof(*bp) + sizeof(*th));
1587 return crypto_ahash_update(hp->req);
1588}
1589
1590static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1591 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1592{
1593 struct tcp_sigpool hp;
1594
1595 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1596 goto clear_hash_nostart;
1597
1598 if (crypto_ahash_init(hp.req))
1599 goto clear_hash;
1600 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1601 goto clear_hash;
1602 if (tcp_md5_hash_key(&hp, key))
1603 goto clear_hash;
1604 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1605 if (crypto_ahash_final(hp.req))
1606 goto clear_hash;
1607
1608 tcp_sigpool_end(&hp);
1609 return 0;
1610
1611clear_hash:
1612 tcp_sigpool_end(&hp);
1613clear_hash_nostart:
1614 memset(md5_hash, 0, 16);
1615 return 1;
1616}
1617
1618int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1619 const struct sock *sk,
1620 const struct sk_buff *skb)
1621{
1622 const struct tcphdr *th = tcp_hdr(skb);
1623 struct tcp_sigpool hp;
1624 __be32 saddr, daddr;
1625
1626 if (sk) { /* valid for establish/request sockets */
1627 saddr = sk->sk_rcv_saddr;
1628 daddr = sk->sk_daddr;
1629 } else {
1630 const struct iphdr *iph = ip_hdr(skb);
1631 saddr = iph->saddr;
1632 daddr = iph->daddr;
1633 }
1634
1635 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1636 goto clear_hash_nostart;
1637
1638 if (crypto_ahash_init(hp.req))
1639 goto clear_hash;
1640
1641 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1642 goto clear_hash;
1643 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1644 goto clear_hash;
1645 if (tcp_md5_hash_key(&hp, key))
1646 goto clear_hash;
1647 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1648 if (crypto_ahash_final(hp.req))
1649 goto clear_hash;
1650
1651 tcp_sigpool_end(&hp);
1652 return 0;
1653
1654clear_hash:
1655 tcp_sigpool_end(&hp);
1656clear_hash_nostart:
1657 memset(md5_hash, 0, 16);
1658 return 1;
1659}
1660EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1661
1662#endif
1663
1664static void tcp_v4_init_req(struct request_sock *req,
1665 const struct sock *sk_listener,
1666 struct sk_buff *skb)
1667{
1668 struct inet_request_sock *ireq = inet_rsk(req);
1669 struct net *net = sock_net(sk_listener);
1670
1671 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1672 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1673 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1674}
1675
1676static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1677 struct sk_buff *skb,
1678 struct flowi *fl,
1679 struct request_sock *req,
1680 u32 tw_isn)
1681{
1682 tcp_v4_init_req(req, sk, skb);
1683
1684 if (security_inet_conn_request(sk, skb, req))
1685 return NULL;
1686
1687 return inet_csk_route_req(sk, &fl->u.ip4, req);
1688}
1689
1690struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1691 .family = PF_INET,
1692 .obj_size = sizeof(struct tcp_request_sock),
1693 .rtx_syn_ack = tcp_rtx_synack,
1694 .send_ack = tcp_v4_reqsk_send_ack,
1695 .destructor = tcp_v4_reqsk_destructor,
1696 .send_reset = tcp_v4_send_reset,
1697 .syn_ack_timeout = tcp_syn_ack_timeout,
1698};
1699
1700const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1701 .mss_clamp = TCP_MSS_DEFAULT,
1702#ifdef CONFIG_TCP_MD5SIG
1703 .req_md5_lookup = tcp_v4_md5_lookup,
1704 .calc_md5_hash = tcp_v4_md5_hash_skb,
1705#endif
1706#ifdef CONFIG_TCP_AO
1707 .ao_lookup = tcp_v4_ao_lookup_rsk,
1708 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1709 .ao_synack_hash = tcp_v4_ao_synack_hash,
1710#endif
1711#ifdef CONFIG_SYN_COOKIES
1712 .cookie_init_seq = cookie_v4_init_sequence,
1713#endif
1714 .route_req = tcp_v4_route_req,
1715 .init_seq = tcp_v4_init_seq,
1716 .init_ts_off = tcp_v4_init_ts_off,
1717 .send_synack = tcp_v4_send_synack,
1718};
1719
1720int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1721{
1722 /* Never answer to SYNs send to broadcast or multicast */
1723 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1724 goto drop;
1725
1726 return tcp_conn_request(&tcp_request_sock_ops,
1727 &tcp_request_sock_ipv4_ops, sk, skb);
1728
1729drop:
1730 tcp_listendrop(sk);
1731 return 0;
1732}
1733EXPORT_SYMBOL(tcp_v4_conn_request);
1734
1735
1736/*
1737 * The three way handshake has completed - we got a valid synack -
1738 * now create the new socket.
1739 */
1740struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1741 struct request_sock *req,
1742 struct dst_entry *dst,
1743 struct request_sock *req_unhash,
1744 bool *own_req)
1745{
1746 struct inet_request_sock *ireq;
1747 bool found_dup_sk = false;
1748 struct inet_sock *newinet;
1749 struct tcp_sock *newtp;
1750 struct sock *newsk;
1751#ifdef CONFIG_TCP_MD5SIG
1752 const union tcp_md5_addr *addr;
1753 struct tcp_md5sig_key *key;
1754 int l3index;
1755#endif
1756 struct ip_options_rcu *inet_opt;
1757
1758 if (sk_acceptq_is_full(sk))
1759 goto exit_overflow;
1760
1761 newsk = tcp_create_openreq_child(sk, req, skb);
1762 if (!newsk)
1763 goto exit_nonewsk;
1764
1765 newsk->sk_gso_type = SKB_GSO_TCPV4;
1766 inet_sk_rx_dst_set(newsk, skb);
1767
1768 newtp = tcp_sk(newsk);
1769 newinet = inet_sk(newsk);
1770 ireq = inet_rsk(req);
1771 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1772 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1773 newsk->sk_bound_dev_if = ireq->ir_iif;
1774 newinet->inet_saddr = ireq->ir_loc_addr;
1775 inet_opt = rcu_dereference(ireq->ireq_opt);
1776 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1777 newinet->mc_index = inet_iif(skb);
1778 newinet->mc_ttl = ip_hdr(skb)->ttl;
1779 newinet->rcv_tos = ip_hdr(skb)->tos;
1780 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1781 if (inet_opt)
1782 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1783 atomic_set(&newinet->inet_id, get_random_u16());
1784
1785 /* Set ToS of the new socket based upon the value of incoming SYN.
1786 * ECT bits are set later in tcp_init_transfer().
1787 */
1788 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1789 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1790
1791 if (!dst) {
1792 dst = inet_csk_route_child_sock(sk, newsk, req);
1793 if (!dst)
1794 goto put_and_exit;
1795 } else {
1796 /* syncookie case : see end of cookie_v4_check() */
1797 }
1798 sk_setup_caps(newsk, dst);
1799
1800 tcp_ca_openreq_child(newsk, dst);
1801
1802 tcp_sync_mss(newsk, dst_mtu(dst));
1803 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1804
1805 tcp_initialize_rcv_mss(newsk);
1806
1807#ifdef CONFIG_TCP_MD5SIG
1808 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1809 /* Copy over the MD5 key from the original socket */
1810 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1811 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1812 if (key && !tcp_rsk_used_ao(req)) {
1813 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1814 goto put_and_exit;
1815 sk_gso_disable(newsk);
1816 }
1817#endif
1818#ifdef CONFIG_TCP_AO
1819 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1820 goto put_and_exit; /* OOM, release back memory */
1821#endif
1822
1823 if (__inet_inherit_port(sk, newsk) < 0)
1824 goto put_and_exit;
1825 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1826 &found_dup_sk);
1827 if (likely(*own_req)) {
1828 tcp_move_syn(newtp, req);
1829 ireq->ireq_opt = NULL;
1830 } else {
1831 newinet->inet_opt = NULL;
1832
1833 if (!req_unhash && found_dup_sk) {
1834 /* This code path should only be executed in the
1835 * syncookie case only
1836 */
1837 bh_unlock_sock(newsk);
1838 sock_put(newsk);
1839 newsk = NULL;
1840 }
1841 }
1842 return newsk;
1843
1844exit_overflow:
1845 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1846exit_nonewsk:
1847 dst_release(dst);
1848exit:
1849 tcp_listendrop(sk);
1850 return NULL;
1851put_and_exit:
1852 newinet->inet_opt = NULL;
1853 inet_csk_prepare_forced_close(newsk);
1854 tcp_done(newsk);
1855 goto exit;
1856}
1857EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1858
1859static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1860{
1861#ifdef CONFIG_SYN_COOKIES
1862 const struct tcphdr *th = tcp_hdr(skb);
1863
1864 if (!th->syn)
1865 sk = cookie_v4_check(sk, skb);
1866#endif
1867 return sk;
1868}
1869
1870u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1871 struct tcphdr *th, u32 *cookie)
1872{
1873 u16 mss = 0;
1874#ifdef CONFIG_SYN_COOKIES
1875 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1876 &tcp_request_sock_ipv4_ops, sk, th);
1877 if (mss) {
1878 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1879 tcp_synq_overflow(sk);
1880 }
1881#endif
1882 return mss;
1883}
1884
1885INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1886 u32));
1887/* The socket must have it's spinlock held when we get
1888 * here, unless it is a TCP_LISTEN socket.
1889 *
1890 * We have a potential double-lock case here, so even when
1891 * doing backlog processing we use the BH locking scheme.
1892 * This is because we cannot sleep with the original spinlock
1893 * held.
1894 */
1895int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1896{
1897 enum skb_drop_reason reason;
1898 struct sock *rsk;
1899
1900 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1901 struct dst_entry *dst;
1902
1903 dst = rcu_dereference_protected(sk->sk_rx_dst,
1904 lockdep_sock_is_held(sk));
1905
1906 sock_rps_save_rxhash(sk, skb);
1907 sk_mark_napi_id(sk, skb);
1908 if (dst) {
1909 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1910 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1911 dst, 0)) {
1912 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1913 dst_release(dst);
1914 }
1915 }
1916 tcp_rcv_established(sk, skb);
1917 return 0;
1918 }
1919
1920 if (tcp_checksum_complete(skb))
1921 goto csum_err;
1922
1923 if (sk->sk_state == TCP_LISTEN) {
1924 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1925
1926 if (!nsk)
1927 return 0;
1928 if (nsk != sk) {
1929 reason = tcp_child_process(sk, nsk, skb);
1930 if (reason) {
1931 rsk = nsk;
1932 goto reset;
1933 }
1934 return 0;
1935 }
1936 } else
1937 sock_rps_save_rxhash(sk, skb);
1938
1939 reason = tcp_rcv_state_process(sk, skb);
1940 if (reason) {
1941 rsk = sk;
1942 goto reset;
1943 }
1944 return 0;
1945
1946reset:
1947 tcp_v4_send_reset(rsk, skb, sk_rst_convert_drop_reason(reason));
1948discard:
1949 sk_skb_reason_drop(sk, skb, reason);
1950 /* Be careful here. If this function gets more complicated and
1951 * gcc suffers from register pressure on the x86, sk (in %ebx)
1952 * might be destroyed here. This current version compiles correctly,
1953 * but you have been warned.
1954 */
1955 return 0;
1956
1957csum_err:
1958 reason = SKB_DROP_REASON_TCP_CSUM;
1959 trace_tcp_bad_csum(skb);
1960 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1961 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1962 goto discard;
1963}
1964EXPORT_SYMBOL(tcp_v4_do_rcv);
1965
1966int tcp_v4_early_demux(struct sk_buff *skb)
1967{
1968 struct net *net = dev_net(skb->dev);
1969 const struct iphdr *iph;
1970 const struct tcphdr *th;
1971 struct sock *sk;
1972
1973 if (skb->pkt_type != PACKET_HOST)
1974 return 0;
1975
1976 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1977 return 0;
1978
1979 iph = ip_hdr(skb);
1980 th = tcp_hdr(skb);
1981
1982 if (th->doff < sizeof(struct tcphdr) / 4)
1983 return 0;
1984
1985 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1986 iph->saddr, th->source,
1987 iph->daddr, ntohs(th->dest),
1988 skb->skb_iif, inet_sdif(skb));
1989 if (sk) {
1990 skb->sk = sk;
1991 skb->destructor = sock_edemux;
1992 if (sk_fullsock(sk)) {
1993 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1994
1995 if (dst)
1996 dst = dst_check(dst, 0);
1997 if (dst &&
1998 sk->sk_rx_dst_ifindex == skb->skb_iif)
1999 skb_dst_set_noref(skb, dst);
2000 }
2001 }
2002 return 0;
2003}
2004
2005bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
2006 enum skb_drop_reason *reason)
2007{
2008 u32 tail_gso_size, tail_gso_segs;
2009 struct skb_shared_info *shinfo;
2010 const struct tcphdr *th;
2011 struct tcphdr *thtail;
2012 struct sk_buff *tail;
2013 unsigned int hdrlen;
2014 bool fragstolen;
2015 u32 gso_segs;
2016 u32 gso_size;
2017 u64 limit;
2018 int delta;
2019
2020 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2021 * we can fix skb->truesize to its real value to avoid future drops.
2022 * This is valid because skb is not yet charged to the socket.
2023 * It has been noticed pure SACK packets were sometimes dropped
2024 * (if cooked by drivers without copybreak feature).
2025 */
2026 skb_condense(skb);
2027
2028 tcp_cleanup_skb(skb);
2029
2030 if (unlikely(tcp_checksum_complete(skb))) {
2031 bh_unlock_sock(sk);
2032 trace_tcp_bad_csum(skb);
2033 *reason = SKB_DROP_REASON_TCP_CSUM;
2034 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2035 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2036 return true;
2037 }
2038
2039 /* Attempt coalescing to last skb in backlog, even if we are
2040 * above the limits.
2041 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2042 */
2043 th = (const struct tcphdr *)skb->data;
2044 hdrlen = th->doff * 4;
2045
2046 tail = sk->sk_backlog.tail;
2047 if (!tail)
2048 goto no_coalesce;
2049 thtail = (struct tcphdr *)tail->data;
2050
2051 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2052 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2053 ((TCP_SKB_CB(tail)->tcp_flags |
2054 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2055 !((TCP_SKB_CB(tail)->tcp_flags &
2056 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2057 ((TCP_SKB_CB(tail)->tcp_flags ^
2058 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2059 !tcp_skb_can_collapse_rx(tail, skb) ||
2060 thtail->doff != th->doff ||
2061 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2062 goto no_coalesce;
2063
2064 __skb_pull(skb, hdrlen);
2065
2066 shinfo = skb_shinfo(skb);
2067 gso_size = shinfo->gso_size ?: skb->len;
2068 gso_segs = shinfo->gso_segs ?: 1;
2069
2070 shinfo = skb_shinfo(tail);
2071 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2072 tail_gso_segs = shinfo->gso_segs ?: 1;
2073
2074 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2075 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2076
2077 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2078 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2079 thtail->window = th->window;
2080 }
2081
2082 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2083 * thtail->fin, so that the fast path in tcp_rcv_established()
2084 * is not entered if we append a packet with a FIN.
2085 * SYN, RST, URG are not present.
2086 * ACK is set on both packets.
2087 * PSH : we do not really care in TCP stack,
2088 * at least for 'GRO' packets.
2089 */
2090 thtail->fin |= th->fin;
2091 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2092
2093 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2094 TCP_SKB_CB(tail)->has_rxtstamp = true;
2095 tail->tstamp = skb->tstamp;
2096 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2097 }
2098
2099 /* Not as strict as GRO. We only need to carry mss max value */
2100 shinfo->gso_size = max(gso_size, tail_gso_size);
2101 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2102
2103 sk->sk_backlog.len += delta;
2104 __NET_INC_STATS(sock_net(sk),
2105 LINUX_MIB_TCPBACKLOGCOALESCE);
2106 kfree_skb_partial(skb, fragstolen);
2107 return false;
2108 }
2109 __skb_push(skb, hdrlen);
2110
2111no_coalesce:
2112 /* sk->sk_backlog.len is reset only at the end of __release_sock().
2113 * Both sk->sk_backlog.len and sk->sk_rmem_alloc could reach
2114 * sk_rcvbuf in normal conditions.
2115 */
2116 limit = ((u64)READ_ONCE(sk->sk_rcvbuf)) << 1;
2117
2118 limit += ((u32)READ_ONCE(sk->sk_sndbuf)) >> 1;
2119
2120 /* Only socket owner can try to collapse/prune rx queues
2121 * to reduce memory overhead, so add a little headroom here.
2122 * Few sockets backlog are possibly concurrently non empty.
2123 */
2124 limit += 64 * 1024;
2125
2126 limit = min_t(u64, limit, UINT_MAX);
2127
2128 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2129 bh_unlock_sock(sk);
2130 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2131 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2132 return true;
2133 }
2134 return false;
2135}
2136EXPORT_SYMBOL(tcp_add_backlog);
2137
2138int tcp_filter(struct sock *sk, struct sk_buff *skb)
2139{
2140 struct tcphdr *th = (struct tcphdr *)skb->data;
2141
2142 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2143}
2144EXPORT_SYMBOL(tcp_filter);
2145
2146static void tcp_v4_restore_cb(struct sk_buff *skb)
2147{
2148 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2149 sizeof(struct inet_skb_parm));
2150}
2151
2152static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2153 const struct tcphdr *th)
2154{
2155 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2156 * barrier() makes sure compiler wont play fool^Waliasing games.
2157 */
2158 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2159 sizeof(struct inet_skb_parm));
2160 barrier();
2161
2162 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2163 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2164 skb->len - th->doff * 4);
2165 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2166 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
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 struct sock *sk = NULL;
2186 bool refcounted;
2187 int ret;
2188 u32 isn;
2189
2190 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2191 if (skb->pkt_type != PACKET_HOST)
2192 goto discard_it;
2193
2194 /* Count it even if it's bad */
2195 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2196
2197 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2198 goto discard_it;
2199
2200 th = (const struct tcphdr *)skb->data;
2201
2202 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2203 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2204 goto bad_packet;
2205 }
2206 if (!pskb_may_pull(skb, th->doff * 4))
2207 goto discard_it;
2208
2209 /* An explanation is required here, I think.
2210 * Packet length and doff are validated by header prediction,
2211 * provided case of th->doff==0 is eliminated.
2212 * So, we defer the checks. */
2213
2214 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2215 goto csum_error;
2216
2217 th = (const struct tcphdr *)skb->data;
2218 iph = ip_hdr(skb);
2219lookup:
2220 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2221 skb, __tcp_hdrlen(th), th->source,
2222 th->dest, sdif, &refcounted);
2223 if (!sk)
2224 goto no_tcp_socket;
2225
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 enum sk_rst_reason rst_reason;
2298
2299 rst_reason = sk_rst_convert_drop_reason(drop_reason);
2300 tcp_v4_send_reset(nsk, skb, rst_reason);
2301 goto discard_and_relse;
2302 }
2303 sock_put(sk);
2304 return 0;
2305 }
2306 }
2307
2308process:
2309 if (static_branch_unlikely(&ip4_min_ttl)) {
2310 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2311 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2312 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2313 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2314 goto discard_and_relse;
2315 }
2316 }
2317
2318 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2319 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2320 goto discard_and_relse;
2321 }
2322
2323 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2324 AF_INET, dif, sdif);
2325 if (drop_reason)
2326 goto discard_and_relse;
2327
2328 nf_reset_ct(skb);
2329
2330 if (tcp_filter(sk, skb)) {
2331 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2332 goto discard_and_relse;
2333 }
2334 th = (const struct tcphdr *)skb->data;
2335 iph = ip_hdr(skb);
2336 tcp_v4_fill_cb(skb, iph, th);
2337
2338 skb->dev = NULL;
2339
2340 if (sk->sk_state == TCP_LISTEN) {
2341 ret = tcp_v4_do_rcv(sk, skb);
2342 goto put_and_return;
2343 }
2344
2345 sk_incoming_cpu_update(sk);
2346
2347 bh_lock_sock_nested(sk);
2348 tcp_segs_in(tcp_sk(sk), skb);
2349 ret = 0;
2350 if (!sock_owned_by_user(sk)) {
2351 ret = tcp_v4_do_rcv(sk, skb);
2352 } else {
2353 if (tcp_add_backlog(sk, skb, &drop_reason))
2354 goto discard_and_relse;
2355 }
2356 bh_unlock_sock(sk);
2357
2358put_and_return:
2359 if (refcounted)
2360 sock_put(sk);
2361
2362 return ret;
2363
2364no_tcp_socket:
2365 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2366 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2367 goto discard_it;
2368
2369 tcp_v4_fill_cb(skb, iph, th);
2370
2371 if (tcp_checksum_complete(skb)) {
2372csum_error:
2373 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2374 trace_tcp_bad_csum(skb);
2375 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2376bad_packet:
2377 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2378 } else {
2379 tcp_v4_send_reset(NULL, skb, sk_rst_convert_drop_reason(drop_reason));
2380 }
2381
2382discard_it:
2383 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2384 /* Discard frame. */
2385 sk_skb_reason_drop(sk, skb, drop_reason);
2386 return 0;
2387
2388discard_and_relse:
2389 sk_drops_add(sk, skb);
2390 if (refcounted)
2391 sock_put(sk);
2392 goto discard_it;
2393
2394do_time_wait:
2395 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2396 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2397 inet_twsk_put(inet_twsk(sk));
2398 goto discard_it;
2399 }
2400
2401 tcp_v4_fill_cb(skb, iph, th);
2402
2403 if (tcp_checksum_complete(skb)) {
2404 inet_twsk_put(inet_twsk(sk));
2405 goto csum_error;
2406 }
2407 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn)) {
2408 case TCP_TW_SYN: {
2409 struct sock *sk2 = inet_lookup_listener(net,
2410 net->ipv4.tcp_death_row.hashinfo,
2411 skb, __tcp_hdrlen(th),
2412 iph->saddr, th->source,
2413 iph->daddr, th->dest,
2414 inet_iif(skb),
2415 sdif);
2416 if (sk2) {
2417 inet_twsk_deschedule_put(inet_twsk(sk));
2418 sk = sk2;
2419 tcp_v4_restore_cb(skb);
2420 refcounted = false;
2421 __this_cpu_write(tcp_tw_isn, isn);
2422 goto process;
2423 }
2424 }
2425 /* to ACK */
2426 fallthrough;
2427 case TCP_TW_ACK:
2428 tcp_v4_timewait_ack(sk, skb);
2429 break;
2430 case TCP_TW_RST:
2431 tcp_v4_send_reset(sk, skb, SK_RST_REASON_TCP_TIMEWAIT_SOCKET);
2432 inet_twsk_deschedule_put(inet_twsk(sk));
2433 goto discard_it;
2434 case TCP_TW_SUCCESS:;
2435 }
2436 goto discard_it;
2437}
2438
2439static struct timewait_sock_ops tcp_timewait_sock_ops = {
2440 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2441 .twsk_destructor= tcp_twsk_destructor,
2442};
2443
2444void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2445{
2446 struct dst_entry *dst = skb_dst(skb);
2447
2448 if (dst && dst_hold_safe(dst)) {
2449 rcu_assign_pointer(sk->sk_rx_dst, dst);
2450 sk->sk_rx_dst_ifindex = skb->skb_iif;
2451 }
2452}
2453EXPORT_SYMBOL(inet_sk_rx_dst_set);
2454
2455const struct inet_connection_sock_af_ops ipv4_specific = {
2456 .queue_xmit = ip_queue_xmit,
2457 .send_check = tcp_v4_send_check,
2458 .rebuild_header = inet_sk_rebuild_header,
2459 .sk_rx_dst_set = inet_sk_rx_dst_set,
2460 .conn_request = tcp_v4_conn_request,
2461 .syn_recv_sock = tcp_v4_syn_recv_sock,
2462 .net_header_len = sizeof(struct iphdr),
2463 .setsockopt = ip_setsockopt,
2464 .getsockopt = ip_getsockopt,
2465 .addr2sockaddr = inet_csk_addr2sockaddr,
2466 .sockaddr_len = sizeof(struct sockaddr_in),
2467 .mtu_reduced = tcp_v4_mtu_reduced,
2468};
2469EXPORT_SYMBOL(ipv4_specific);
2470
2471#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2472static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2473#ifdef CONFIG_TCP_MD5SIG
2474 .md5_lookup = tcp_v4_md5_lookup,
2475 .calc_md5_hash = tcp_v4_md5_hash_skb,
2476 .md5_parse = tcp_v4_parse_md5_keys,
2477#endif
2478#ifdef CONFIG_TCP_AO
2479 .ao_lookup = tcp_v4_ao_lookup,
2480 .calc_ao_hash = tcp_v4_ao_hash_skb,
2481 .ao_parse = tcp_v4_parse_ao,
2482 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2483#endif
2484};
2485#endif
2486
2487/* NOTE: A lot of things set to zero explicitly by call to
2488 * sk_alloc() so need not be done here.
2489 */
2490static int tcp_v4_init_sock(struct sock *sk)
2491{
2492 struct inet_connection_sock *icsk = inet_csk(sk);
2493
2494 tcp_init_sock(sk);
2495
2496 icsk->icsk_af_ops = &ipv4_specific;
2497
2498#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2499 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2500#endif
2501
2502 return 0;
2503}
2504
2505#ifdef CONFIG_TCP_MD5SIG
2506static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2507{
2508 struct tcp_md5sig_info *md5sig;
2509
2510 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2511 kfree(md5sig);
2512 static_branch_slow_dec_deferred(&tcp_md5_needed);
2513 tcp_md5_release_sigpool();
2514}
2515#endif
2516
2517static void tcp_release_user_frags(struct sock *sk)
2518{
2519#ifdef CONFIG_PAGE_POOL
2520 unsigned long index;
2521 void *netmem;
2522
2523 xa_for_each(&sk->sk_user_frags, index, netmem)
2524 WARN_ON_ONCE(!napi_pp_put_page((__force netmem_ref)netmem));
2525#endif
2526}
2527
2528void tcp_v4_destroy_sock(struct sock *sk)
2529{
2530 struct tcp_sock *tp = tcp_sk(sk);
2531
2532 tcp_release_user_frags(sk);
2533
2534 xa_destroy(&sk->sk_user_frags);
2535
2536 trace_tcp_destroy_sock(sk);
2537
2538 tcp_clear_xmit_timers(sk);
2539
2540 tcp_cleanup_congestion_control(sk);
2541
2542 tcp_cleanup_ulp(sk);
2543
2544 /* Cleanup up the write buffer. */
2545 tcp_write_queue_purge(sk);
2546
2547 /* Check if we want to disable active TFO */
2548 tcp_fastopen_active_disable_ofo_check(sk);
2549
2550 /* Cleans up our, hopefully empty, out_of_order_queue. */
2551 skb_rbtree_purge(&tp->out_of_order_queue);
2552
2553#ifdef CONFIG_TCP_MD5SIG
2554 /* Clean up the MD5 key list, if any */
2555 if (tp->md5sig_info) {
2556 struct tcp_md5sig_info *md5sig;
2557
2558 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2559 tcp_clear_md5_list(sk);
2560 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2561 rcu_assign_pointer(tp->md5sig_info, NULL);
2562 }
2563#endif
2564 tcp_ao_destroy_sock(sk, false);
2565
2566 /* Clean up a referenced TCP bind bucket. */
2567 if (inet_csk(sk)->icsk_bind_hash)
2568 inet_put_port(sk);
2569
2570 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2571
2572 /* If socket is aborted during connect operation */
2573 tcp_free_fastopen_req(tp);
2574 tcp_fastopen_destroy_cipher(sk);
2575 tcp_saved_syn_free(tp);
2576
2577 sk_sockets_allocated_dec(sk);
2578}
2579EXPORT_SYMBOL(tcp_v4_destroy_sock);
2580
2581#ifdef CONFIG_PROC_FS
2582/* Proc filesystem TCP sock list dumping. */
2583
2584static unsigned short seq_file_family(const struct seq_file *seq);
2585
2586static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2587{
2588 unsigned short family = seq_file_family(seq);
2589
2590 /* AF_UNSPEC is used as a match all */
2591 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2592 net_eq(sock_net(sk), seq_file_net(seq)));
2593}
2594
2595/* Find a non empty bucket (starting from st->bucket)
2596 * and return the first sk from it.
2597 */
2598static void *listening_get_first(struct seq_file *seq)
2599{
2600 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2601 struct tcp_iter_state *st = seq->private;
2602
2603 st->offset = 0;
2604 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2605 struct inet_listen_hashbucket *ilb2;
2606 struct hlist_nulls_node *node;
2607 struct sock *sk;
2608
2609 ilb2 = &hinfo->lhash2[st->bucket];
2610 if (hlist_nulls_empty(&ilb2->nulls_head))
2611 continue;
2612
2613 spin_lock(&ilb2->lock);
2614 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2615 if (seq_sk_match(seq, sk))
2616 return sk;
2617 }
2618 spin_unlock(&ilb2->lock);
2619 }
2620
2621 return NULL;
2622}
2623
2624/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2625 * If "cur" is the last one in the st->bucket,
2626 * call listening_get_first() to return the first sk of the next
2627 * non empty bucket.
2628 */
2629static void *listening_get_next(struct seq_file *seq, void *cur)
2630{
2631 struct tcp_iter_state *st = seq->private;
2632 struct inet_listen_hashbucket *ilb2;
2633 struct hlist_nulls_node *node;
2634 struct inet_hashinfo *hinfo;
2635 struct sock *sk = cur;
2636
2637 ++st->num;
2638 ++st->offset;
2639
2640 sk = sk_nulls_next(sk);
2641 sk_nulls_for_each_from(sk, node) {
2642 if (seq_sk_match(seq, sk))
2643 return sk;
2644 }
2645
2646 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2647 ilb2 = &hinfo->lhash2[st->bucket];
2648 spin_unlock(&ilb2->lock);
2649 ++st->bucket;
2650 return listening_get_first(seq);
2651}
2652
2653static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2654{
2655 struct tcp_iter_state *st = seq->private;
2656 void *rc;
2657
2658 st->bucket = 0;
2659 st->offset = 0;
2660 rc = listening_get_first(seq);
2661
2662 while (rc && *pos) {
2663 rc = listening_get_next(seq, rc);
2664 --*pos;
2665 }
2666 return rc;
2667}
2668
2669static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2670 const struct tcp_iter_state *st)
2671{
2672 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2673}
2674
2675/*
2676 * Get first established socket starting from bucket given in st->bucket.
2677 * If st->bucket is zero, the very first socket in the hash is returned.
2678 */
2679static void *established_get_first(struct seq_file *seq)
2680{
2681 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2682 struct tcp_iter_state *st = seq->private;
2683
2684 st->offset = 0;
2685 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2686 struct sock *sk;
2687 struct hlist_nulls_node *node;
2688 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2689
2690 cond_resched();
2691
2692 /* Lockless fast path for the common case of empty buckets */
2693 if (empty_bucket(hinfo, st))
2694 continue;
2695
2696 spin_lock_bh(lock);
2697 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2698 if (seq_sk_match(seq, sk))
2699 return sk;
2700 }
2701 spin_unlock_bh(lock);
2702 }
2703
2704 return NULL;
2705}
2706
2707static void *established_get_next(struct seq_file *seq, void *cur)
2708{
2709 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2710 struct tcp_iter_state *st = seq->private;
2711 struct hlist_nulls_node *node;
2712 struct sock *sk = cur;
2713
2714 ++st->num;
2715 ++st->offset;
2716
2717 sk = sk_nulls_next(sk);
2718
2719 sk_nulls_for_each_from(sk, node) {
2720 if (seq_sk_match(seq, sk))
2721 return sk;
2722 }
2723
2724 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2725 ++st->bucket;
2726 return established_get_first(seq);
2727}
2728
2729static void *established_get_idx(struct seq_file *seq, loff_t pos)
2730{
2731 struct tcp_iter_state *st = seq->private;
2732 void *rc;
2733
2734 st->bucket = 0;
2735 rc = established_get_first(seq);
2736
2737 while (rc && pos) {
2738 rc = established_get_next(seq, rc);
2739 --pos;
2740 }
2741 return rc;
2742}
2743
2744static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2745{
2746 void *rc;
2747 struct tcp_iter_state *st = seq->private;
2748
2749 st->state = TCP_SEQ_STATE_LISTENING;
2750 rc = listening_get_idx(seq, &pos);
2751
2752 if (!rc) {
2753 st->state = TCP_SEQ_STATE_ESTABLISHED;
2754 rc = established_get_idx(seq, pos);
2755 }
2756
2757 return rc;
2758}
2759
2760static void *tcp_seek_last_pos(struct seq_file *seq)
2761{
2762 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2763 struct tcp_iter_state *st = seq->private;
2764 int bucket = st->bucket;
2765 int offset = st->offset;
2766 int orig_num = st->num;
2767 void *rc = NULL;
2768
2769 switch (st->state) {
2770 case TCP_SEQ_STATE_LISTENING:
2771 if (st->bucket > hinfo->lhash2_mask)
2772 break;
2773 rc = listening_get_first(seq);
2774 while (offset-- && rc && bucket == st->bucket)
2775 rc = listening_get_next(seq, rc);
2776 if (rc)
2777 break;
2778 st->bucket = 0;
2779 st->state = TCP_SEQ_STATE_ESTABLISHED;
2780 fallthrough;
2781 case TCP_SEQ_STATE_ESTABLISHED:
2782 if (st->bucket > hinfo->ehash_mask)
2783 break;
2784 rc = established_get_first(seq);
2785 while (offset-- && rc && bucket == st->bucket)
2786 rc = established_get_next(seq, rc);
2787 }
2788
2789 st->num = orig_num;
2790
2791 return rc;
2792}
2793
2794void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2795{
2796 struct tcp_iter_state *st = seq->private;
2797 void *rc;
2798
2799 if (*pos && *pos == st->last_pos) {
2800 rc = tcp_seek_last_pos(seq);
2801 if (rc)
2802 goto out;
2803 }
2804
2805 st->state = TCP_SEQ_STATE_LISTENING;
2806 st->num = 0;
2807 st->bucket = 0;
2808 st->offset = 0;
2809 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2810
2811out:
2812 st->last_pos = *pos;
2813 return rc;
2814}
2815EXPORT_SYMBOL(tcp_seq_start);
2816
2817void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2818{
2819 struct tcp_iter_state *st = seq->private;
2820 void *rc = NULL;
2821
2822 if (v == SEQ_START_TOKEN) {
2823 rc = tcp_get_idx(seq, 0);
2824 goto out;
2825 }
2826
2827 switch (st->state) {
2828 case TCP_SEQ_STATE_LISTENING:
2829 rc = listening_get_next(seq, v);
2830 if (!rc) {
2831 st->state = TCP_SEQ_STATE_ESTABLISHED;
2832 st->bucket = 0;
2833 st->offset = 0;
2834 rc = established_get_first(seq);
2835 }
2836 break;
2837 case TCP_SEQ_STATE_ESTABLISHED:
2838 rc = established_get_next(seq, v);
2839 break;
2840 }
2841out:
2842 ++*pos;
2843 st->last_pos = *pos;
2844 return rc;
2845}
2846EXPORT_SYMBOL(tcp_seq_next);
2847
2848void tcp_seq_stop(struct seq_file *seq, void *v)
2849{
2850 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2851 struct tcp_iter_state *st = seq->private;
2852
2853 switch (st->state) {
2854 case TCP_SEQ_STATE_LISTENING:
2855 if (v != SEQ_START_TOKEN)
2856 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2857 break;
2858 case TCP_SEQ_STATE_ESTABLISHED:
2859 if (v)
2860 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2861 break;
2862 }
2863}
2864EXPORT_SYMBOL(tcp_seq_stop);
2865
2866static void get_openreq4(const struct request_sock *req,
2867 struct seq_file *f, int i)
2868{
2869 const struct inet_request_sock *ireq = inet_rsk(req);
2870 long delta = req->rsk_timer.expires - jiffies;
2871
2872 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2873 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2874 i,
2875 ireq->ir_loc_addr,
2876 ireq->ir_num,
2877 ireq->ir_rmt_addr,
2878 ntohs(ireq->ir_rmt_port),
2879 TCP_SYN_RECV,
2880 0, 0, /* could print option size, but that is af dependent. */
2881 1, /* timers active (only the expire timer) */
2882 jiffies_delta_to_clock_t(delta),
2883 req->num_timeout,
2884 from_kuid_munged(seq_user_ns(f),
2885 sock_i_uid(req->rsk_listener)),
2886 0, /* non standard timer */
2887 0, /* open_requests have no inode */
2888 0,
2889 req);
2890}
2891
2892static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2893{
2894 int timer_active;
2895 unsigned long timer_expires;
2896 const struct tcp_sock *tp = tcp_sk(sk);
2897 const struct inet_connection_sock *icsk = inet_csk(sk);
2898 const struct inet_sock *inet = inet_sk(sk);
2899 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2900 __be32 dest = inet->inet_daddr;
2901 __be32 src = inet->inet_rcv_saddr;
2902 __u16 destp = ntohs(inet->inet_dport);
2903 __u16 srcp = ntohs(inet->inet_sport);
2904 u8 icsk_pending;
2905 int rx_queue;
2906 int state;
2907
2908 icsk_pending = smp_load_acquire(&icsk->icsk_pending);
2909 if (icsk_pending == ICSK_TIME_RETRANS ||
2910 icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2911 icsk_pending == ICSK_TIME_LOSS_PROBE) {
2912 timer_active = 1;
2913 timer_expires = icsk->icsk_timeout;
2914 } else if (icsk_pending == ICSK_TIME_PROBE0) {
2915 timer_active = 4;
2916 timer_expires = icsk->icsk_timeout;
2917 } else if (timer_pending(&sk->sk_timer)) {
2918 timer_active = 2;
2919 timer_expires = sk->sk_timer.expires;
2920 } else {
2921 timer_active = 0;
2922 timer_expires = jiffies;
2923 }
2924
2925 state = inet_sk_state_load(sk);
2926 if (state == TCP_LISTEN)
2927 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2928 else
2929 /* Because we don't lock the socket,
2930 * we might find a transient negative value.
2931 */
2932 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2933 READ_ONCE(tp->copied_seq), 0);
2934
2935 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2936 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2937 i, src, srcp, dest, destp, state,
2938 READ_ONCE(tp->write_seq) - tp->snd_una,
2939 rx_queue,
2940 timer_active,
2941 jiffies_delta_to_clock_t(timer_expires - jiffies),
2942 icsk->icsk_retransmits,
2943 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2944 icsk->icsk_probes_out,
2945 sock_i_ino(sk),
2946 refcount_read(&sk->sk_refcnt), sk,
2947 jiffies_to_clock_t(icsk->icsk_rto),
2948 jiffies_to_clock_t(icsk->icsk_ack.ato),
2949 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2950 tcp_snd_cwnd(tp),
2951 state == TCP_LISTEN ?
2952 fastopenq->max_qlen :
2953 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2954}
2955
2956static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2957 struct seq_file *f, int i)
2958{
2959 long delta = tw->tw_timer.expires - jiffies;
2960 __be32 dest, src;
2961 __u16 destp, srcp;
2962
2963 dest = tw->tw_daddr;
2964 src = tw->tw_rcv_saddr;
2965 destp = ntohs(tw->tw_dport);
2966 srcp = ntohs(tw->tw_sport);
2967
2968 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2969 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2970 i, src, srcp, dest, destp, READ_ONCE(tw->tw_substate), 0, 0,
2971 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2972 refcount_read(&tw->tw_refcnt), tw);
2973}
2974
2975#define TMPSZ 150
2976
2977static int tcp4_seq_show(struct seq_file *seq, void *v)
2978{
2979 struct tcp_iter_state *st;
2980 struct sock *sk = v;
2981
2982 seq_setwidth(seq, TMPSZ - 1);
2983 if (v == SEQ_START_TOKEN) {
2984 seq_puts(seq, " sl local_address rem_address st tx_queue "
2985 "rx_queue tr tm->when retrnsmt uid timeout "
2986 "inode");
2987 goto out;
2988 }
2989 st = seq->private;
2990
2991 if (sk->sk_state == TCP_TIME_WAIT)
2992 get_timewait4_sock(v, seq, st->num);
2993 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2994 get_openreq4(v, seq, st->num);
2995 else
2996 get_tcp4_sock(v, seq, st->num);
2997out:
2998 seq_pad(seq, '\n');
2999 return 0;
3000}
3001
3002#ifdef CONFIG_BPF_SYSCALL
3003struct bpf_tcp_iter_state {
3004 struct tcp_iter_state state;
3005 unsigned int cur_sk;
3006 unsigned int end_sk;
3007 unsigned int max_sk;
3008 struct sock **batch;
3009 bool st_bucket_done;
3010};
3011
3012struct bpf_iter__tcp {
3013 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3014 __bpf_md_ptr(struct sock_common *, sk_common);
3015 uid_t uid __aligned(8);
3016};
3017
3018static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3019 struct sock_common *sk_common, uid_t uid)
3020{
3021 struct bpf_iter__tcp ctx;
3022
3023 meta->seq_num--; /* skip SEQ_START_TOKEN */
3024 ctx.meta = meta;
3025 ctx.sk_common = sk_common;
3026 ctx.uid = uid;
3027 return bpf_iter_run_prog(prog, &ctx);
3028}
3029
3030static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
3031{
3032 while (iter->cur_sk < iter->end_sk)
3033 sock_gen_put(iter->batch[iter->cur_sk++]);
3034}
3035
3036static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
3037 unsigned int new_batch_sz)
3038{
3039 struct sock **new_batch;
3040
3041 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3042 GFP_USER | __GFP_NOWARN);
3043 if (!new_batch)
3044 return -ENOMEM;
3045
3046 bpf_iter_tcp_put_batch(iter);
3047 kvfree(iter->batch);
3048 iter->batch = new_batch;
3049 iter->max_sk = new_batch_sz;
3050
3051 return 0;
3052}
3053
3054static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3055 struct sock *start_sk)
3056{
3057 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3058 struct bpf_tcp_iter_state *iter = seq->private;
3059 struct tcp_iter_state *st = &iter->state;
3060 struct hlist_nulls_node *node;
3061 unsigned int expected = 1;
3062 struct sock *sk;
3063
3064 sock_hold(start_sk);
3065 iter->batch[iter->end_sk++] = start_sk;
3066
3067 sk = sk_nulls_next(start_sk);
3068 sk_nulls_for_each_from(sk, node) {
3069 if (seq_sk_match(seq, sk)) {
3070 if (iter->end_sk < iter->max_sk) {
3071 sock_hold(sk);
3072 iter->batch[iter->end_sk++] = sk;
3073 }
3074 expected++;
3075 }
3076 }
3077 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3078
3079 return expected;
3080}
3081
3082static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3083 struct sock *start_sk)
3084{
3085 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3086 struct bpf_tcp_iter_state *iter = seq->private;
3087 struct tcp_iter_state *st = &iter->state;
3088 struct hlist_nulls_node *node;
3089 unsigned int expected = 1;
3090 struct sock *sk;
3091
3092 sock_hold(start_sk);
3093 iter->batch[iter->end_sk++] = start_sk;
3094
3095 sk = sk_nulls_next(start_sk);
3096 sk_nulls_for_each_from(sk, node) {
3097 if (seq_sk_match(seq, sk)) {
3098 if (iter->end_sk < iter->max_sk) {
3099 sock_hold(sk);
3100 iter->batch[iter->end_sk++] = sk;
3101 }
3102 expected++;
3103 }
3104 }
3105 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3106
3107 return expected;
3108}
3109
3110static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3111{
3112 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3113 struct bpf_tcp_iter_state *iter = seq->private;
3114 struct tcp_iter_state *st = &iter->state;
3115 unsigned int expected;
3116 bool resized = false;
3117 struct sock *sk;
3118
3119 /* The st->bucket is done. Directly advance to the next
3120 * bucket instead of having the tcp_seek_last_pos() to skip
3121 * one by one in the current bucket and eventually find out
3122 * it has to advance to the next bucket.
3123 */
3124 if (iter->st_bucket_done) {
3125 st->offset = 0;
3126 st->bucket++;
3127 if (st->state == TCP_SEQ_STATE_LISTENING &&
3128 st->bucket > hinfo->lhash2_mask) {
3129 st->state = TCP_SEQ_STATE_ESTABLISHED;
3130 st->bucket = 0;
3131 }
3132 }
3133
3134again:
3135 /* Get a new batch */
3136 iter->cur_sk = 0;
3137 iter->end_sk = 0;
3138 iter->st_bucket_done = false;
3139
3140 sk = tcp_seek_last_pos(seq);
3141 if (!sk)
3142 return NULL; /* Done */
3143
3144 if (st->state == TCP_SEQ_STATE_LISTENING)
3145 expected = bpf_iter_tcp_listening_batch(seq, sk);
3146 else
3147 expected = bpf_iter_tcp_established_batch(seq, sk);
3148
3149 if (iter->end_sk == expected) {
3150 iter->st_bucket_done = true;
3151 return sk;
3152 }
3153
3154 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3155 resized = true;
3156 goto again;
3157 }
3158
3159 return sk;
3160}
3161
3162static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3163{
3164 /* bpf iter does not support lseek, so it always
3165 * continue from where it was stop()-ped.
3166 */
3167 if (*pos)
3168 return bpf_iter_tcp_batch(seq);
3169
3170 return SEQ_START_TOKEN;
3171}
3172
3173static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3174{
3175 struct bpf_tcp_iter_state *iter = seq->private;
3176 struct tcp_iter_state *st = &iter->state;
3177 struct sock *sk;
3178
3179 /* Whenever seq_next() is called, the iter->cur_sk is
3180 * done with seq_show(), so advance to the next sk in
3181 * the batch.
3182 */
3183 if (iter->cur_sk < iter->end_sk) {
3184 /* Keeping st->num consistent in tcp_iter_state.
3185 * bpf_iter_tcp does not use st->num.
3186 * meta.seq_num is used instead.
3187 */
3188 st->num++;
3189 /* Move st->offset to the next sk in the bucket such that
3190 * the future start() will resume at st->offset in
3191 * st->bucket. See tcp_seek_last_pos().
3192 */
3193 st->offset++;
3194 sock_gen_put(iter->batch[iter->cur_sk++]);
3195 }
3196
3197 if (iter->cur_sk < iter->end_sk)
3198 sk = iter->batch[iter->cur_sk];
3199 else
3200 sk = bpf_iter_tcp_batch(seq);
3201
3202 ++*pos;
3203 /* Keeping st->last_pos consistent in tcp_iter_state.
3204 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3205 */
3206 st->last_pos = *pos;
3207 return sk;
3208}
3209
3210static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3211{
3212 struct bpf_iter_meta meta;
3213 struct bpf_prog *prog;
3214 struct sock *sk = v;
3215 uid_t uid;
3216 int ret;
3217
3218 if (v == SEQ_START_TOKEN)
3219 return 0;
3220
3221 if (sk_fullsock(sk))
3222 lock_sock(sk);
3223
3224 if (unlikely(sk_unhashed(sk))) {
3225 ret = SEQ_SKIP;
3226 goto unlock;
3227 }
3228
3229 if (sk->sk_state == TCP_TIME_WAIT) {
3230 uid = 0;
3231 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3232 const struct request_sock *req = v;
3233
3234 uid = from_kuid_munged(seq_user_ns(seq),
3235 sock_i_uid(req->rsk_listener));
3236 } else {
3237 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3238 }
3239
3240 meta.seq = seq;
3241 prog = bpf_iter_get_info(&meta, false);
3242 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3243
3244unlock:
3245 if (sk_fullsock(sk))
3246 release_sock(sk);
3247 return ret;
3248
3249}
3250
3251static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3252{
3253 struct bpf_tcp_iter_state *iter = seq->private;
3254 struct bpf_iter_meta meta;
3255 struct bpf_prog *prog;
3256
3257 if (!v) {
3258 meta.seq = seq;
3259 prog = bpf_iter_get_info(&meta, true);
3260 if (prog)
3261 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3262 }
3263
3264 if (iter->cur_sk < iter->end_sk) {
3265 bpf_iter_tcp_put_batch(iter);
3266 iter->st_bucket_done = false;
3267 }
3268}
3269
3270static const struct seq_operations bpf_iter_tcp_seq_ops = {
3271 .show = bpf_iter_tcp_seq_show,
3272 .start = bpf_iter_tcp_seq_start,
3273 .next = bpf_iter_tcp_seq_next,
3274 .stop = bpf_iter_tcp_seq_stop,
3275};
3276#endif
3277static unsigned short seq_file_family(const struct seq_file *seq)
3278{
3279 const struct tcp_seq_afinfo *afinfo;
3280
3281#ifdef CONFIG_BPF_SYSCALL
3282 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3283 if (seq->op == &bpf_iter_tcp_seq_ops)
3284 return AF_UNSPEC;
3285#endif
3286
3287 /* Iterated from proc fs */
3288 afinfo = pde_data(file_inode(seq->file));
3289 return afinfo->family;
3290}
3291
3292static const struct seq_operations tcp4_seq_ops = {
3293 .show = tcp4_seq_show,
3294 .start = tcp_seq_start,
3295 .next = tcp_seq_next,
3296 .stop = tcp_seq_stop,
3297};
3298
3299static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3300 .family = AF_INET,
3301};
3302
3303static int __net_init tcp4_proc_init_net(struct net *net)
3304{
3305 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3306 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3307 return -ENOMEM;
3308 return 0;
3309}
3310
3311static void __net_exit tcp4_proc_exit_net(struct net *net)
3312{
3313 remove_proc_entry("tcp", net->proc_net);
3314}
3315
3316static struct pernet_operations tcp4_net_ops = {
3317 .init = tcp4_proc_init_net,
3318 .exit = tcp4_proc_exit_net,
3319};
3320
3321int __init tcp4_proc_init(void)
3322{
3323 return register_pernet_subsys(&tcp4_net_ops);
3324}
3325
3326void tcp4_proc_exit(void)
3327{
3328 unregister_pernet_subsys(&tcp4_net_ops);
3329}
3330#endif /* CONFIG_PROC_FS */
3331
3332/* @wake is one when sk_stream_write_space() calls us.
3333 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3334 * This mimics the strategy used in sock_def_write_space().
3335 */
3336bool tcp_stream_memory_free(const struct sock *sk, int wake)
3337{
3338 const struct tcp_sock *tp = tcp_sk(sk);
3339 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3340 READ_ONCE(tp->snd_nxt);
3341
3342 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3343}
3344EXPORT_SYMBOL(tcp_stream_memory_free);
3345
3346struct proto tcp_prot = {
3347 .name = "TCP",
3348 .owner = THIS_MODULE,
3349 .close = tcp_close,
3350 .pre_connect = tcp_v4_pre_connect,
3351 .connect = tcp_v4_connect,
3352 .disconnect = tcp_disconnect,
3353 .accept = inet_csk_accept,
3354 .ioctl = tcp_ioctl,
3355 .init = tcp_v4_init_sock,
3356 .destroy = tcp_v4_destroy_sock,
3357 .shutdown = tcp_shutdown,
3358 .setsockopt = tcp_setsockopt,
3359 .getsockopt = tcp_getsockopt,
3360 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3361 .keepalive = tcp_set_keepalive,
3362 .recvmsg = tcp_recvmsg,
3363 .sendmsg = tcp_sendmsg,
3364 .splice_eof = tcp_splice_eof,
3365 .backlog_rcv = tcp_v4_do_rcv,
3366 .release_cb = tcp_release_cb,
3367 .hash = inet_hash,
3368 .unhash = inet_unhash,
3369 .get_port = inet_csk_get_port,
3370 .put_port = inet_put_port,
3371#ifdef CONFIG_BPF_SYSCALL
3372 .psock_update_sk_prot = tcp_bpf_update_proto,
3373#endif
3374 .enter_memory_pressure = tcp_enter_memory_pressure,
3375 .leave_memory_pressure = tcp_leave_memory_pressure,
3376 .stream_memory_free = tcp_stream_memory_free,
3377 .sockets_allocated = &tcp_sockets_allocated,
3378 .orphan_count = &tcp_orphan_count,
3379
3380 .memory_allocated = &tcp_memory_allocated,
3381 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3382
3383 .memory_pressure = &tcp_memory_pressure,
3384 .sysctl_mem = sysctl_tcp_mem,
3385 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3386 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3387 .max_header = MAX_TCP_HEADER,
3388 .obj_size = sizeof(struct tcp_sock),
3389 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3390 .twsk_prot = &tcp_timewait_sock_ops,
3391 .rsk_prot = &tcp_request_sock_ops,
3392 .h.hashinfo = NULL,
3393 .no_autobind = true,
3394 .diag_destroy = tcp_abort,
3395};
3396EXPORT_SYMBOL(tcp_prot);
3397
3398static void __net_exit tcp_sk_exit(struct net *net)
3399{
3400 if (net->ipv4.tcp_congestion_control)
3401 bpf_module_put(net->ipv4.tcp_congestion_control,
3402 net->ipv4.tcp_congestion_control->owner);
3403}
3404
3405static void __net_init tcp_set_hashinfo(struct net *net)
3406{
3407 struct inet_hashinfo *hinfo;
3408 unsigned int ehash_entries;
3409 struct net *old_net;
3410
3411 if (net_eq(net, &init_net))
3412 goto fallback;
3413
3414 old_net = current->nsproxy->net_ns;
3415 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3416 if (!ehash_entries)
3417 goto fallback;
3418
3419 ehash_entries = roundup_pow_of_two(ehash_entries);
3420 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3421 if (!hinfo) {
3422 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3423 "for a netns, fallback to the global one\n",
3424 ehash_entries);
3425fallback:
3426 hinfo = &tcp_hashinfo;
3427 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3428 }
3429
3430 net->ipv4.tcp_death_row.hashinfo = hinfo;
3431 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3432 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3433}
3434
3435static int __net_init tcp_sk_init(struct net *net)
3436{
3437 net->ipv4.sysctl_tcp_ecn = 2;
3438 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3439
3440 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3441 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3442 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3443 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3444 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3445
3446 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3447 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3448 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3449
3450 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3451 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3452 net->ipv4.sysctl_tcp_syncookies = 1;
3453 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3454 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3455 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3456 net->ipv4.sysctl_tcp_orphan_retries = 0;
3457 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3458 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3459 net->ipv4.sysctl_tcp_tw_reuse = 2;
3460 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3461
3462 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3463 tcp_set_hashinfo(net);
3464
3465 net->ipv4.sysctl_tcp_sack = 1;
3466 net->ipv4.sysctl_tcp_window_scaling = 1;
3467 net->ipv4.sysctl_tcp_timestamps = 1;
3468 net->ipv4.sysctl_tcp_early_retrans = 3;
3469 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3470 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3471 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3472 net->ipv4.sysctl_tcp_max_reordering = 300;
3473 net->ipv4.sysctl_tcp_dsack = 1;
3474 net->ipv4.sysctl_tcp_app_win = 31;
3475 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3476 net->ipv4.sysctl_tcp_frto = 2;
3477 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3478 /* This limits the percentage of the congestion window which we
3479 * will allow a single TSO frame to consume. Building TSO frames
3480 * which are too large can cause TCP streams to be bursty.
3481 */
3482 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3483 /* Default TSQ limit of 16 TSO segments */
3484 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3485
3486 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3487 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3488
3489 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3490 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3491 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3492 net->ipv4.sysctl_tcp_autocorking = 1;
3493 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3494 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3495 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3496 if (net != &init_net) {
3497 memcpy(net->ipv4.sysctl_tcp_rmem,
3498 init_net.ipv4.sysctl_tcp_rmem,
3499 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3500 memcpy(net->ipv4.sysctl_tcp_wmem,
3501 init_net.ipv4.sysctl_tcp_wmem,
3502 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3503 }
3504 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3505 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3506 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3507 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3508 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3509 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3510 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3511
3512 /* Set default values for PLB */
3513 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3514 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3515 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3516 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3517 /* Default congestion threshold for PLB to mark a round is 50% */
3518 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3519
3520 /* Reno is always built in */
3521 if (!net_eq(net, &init_net) &&
3522 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3523 init_net.ipv4.tcp_congestion_control->owner))
3524 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3525 else
3526 net->ipv4.tcp_congestion_control = &tcp_reno;
3527
3528 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3529 net->ipv4.sysctl_tcp_shrink_window = 0;
3530
3531 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3532 net->ipv4.sysctl_tcp_rto_min_us = jiffies_to_usecs(TCP_RTO_MIN);
3533
3534 return 0;
3535}
3536
3537static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3538{
3539 struct net *net;
3540
3541 /* make sure concurrent calls to tcp_sk_exit_batch from net_cleanup_work
3542 * and failed setup_net error unwinding path are serialized.
3543 *
3544 * tcp_twsk_purge() handles twsk in any dead netns, not just those in
3545 * net_exit_list, the thread that dismantles a particular twsk must
3546 * do so without other thread progressing to refcount_dec_and_test() of
3547 * tcp_death_row.tw_refcount.
3548 */
3549 mutex_lock(&tcp_exit_batch_mutex);
3550
3551 tcp_twsk_purge(net_exit_list);
3552
3553 list_for_each_entry(net, net_exit_list, exit_list) {
3554 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3555 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3556 tcp_fastopen_ctx_destroy(net);
3557 }
3558
3559 mutex_unlock(&tcp_exit_batch_mutex);
3560}
3561
3562static struct pernet_operations __net_initdata tcp_sk_ops = {
3563 .init = tcp_sk_init,
3564 .exit = tcp_sk_exit,
3565 .exit_batch = tcp_sk_exit_batch,
3566};
3567
3568#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3569DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3570 struct sock_common *sk_common, uid_t uid)
3571
3572#define INIT_BATCH_SZ 16
3573
3574static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3575{
3576 struct bpf_tcp_iter_state *iter = priv_data;
3577 int err;
3578
3579 err = bpf_iter_init_seq_net(priv_data, aux);
3580 if (err)
3581 return err;
3582
3583 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3584 if (err) {
3585 bpf_iter_fini_seq_net(priv_data);
3586 return err;
3587 }
3588
3589 return 0;
3590}
3591
3592static void bpf_iter_fini_tcp(void *priv_data)
3593{
3594 struct bpf_tcp_iter_state *iter = priv_data;
3595
3596 bpf_iter_fini_seq_net(priv_data);
3597 kvfree(iter->batch);
3598}
3599
3600static const struct bpf_iter_seq_info tcp_seq_info = {
3601 .seq_ops = &bpf_iter_tcp_seq_ops,
3602 .init_seq_private = bpf_iter_init_tcp,
3603 .fini_seq_private = bpf_iter_fini_tcp,
3604 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3605};
3606
3607static const struct bpf_func_proto *
3608bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3609 const struct bpf_prog *prog)
3610{
3611 switch (func_id) {
3612 case BPF_FUNC_setsockopt:
3613 return &bpf_sk_setsockopt_proto;
3614 case BPF_FUNC_getsockopt:
3615 return &bpf_sk_getsockopt_proto;
3616 default:
3617 return NULL;
3618 }
3619}
3620
3621static struct bpf_iter_reg tcp_reg_info = {
3622 .target = "tcp",
3623 .ctx_arg_info_size = 1,
3624 .ctx_arg_info = {
3625 { offsetof(struct bpf_iter__tcp, sk_common),
3626 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3627 },
3628 .get_func_proto = bpf_iter_tcp_get_func_proto,
3629 .seq_info = &tcp_seq_info,
3630};
3631
3632static void __init bpf_iter_register(void)
3633{
3634 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3635 if (bpf_iter_reg_target(&tcp_reg_info))
3636 pr_warn("Warning: could not register bpf iterator tcp\n");
3637}
3638
3639#endif
3640
3641void __init tcp_v4_init(void)
3642{
3643 int cpu, res;
3644
3645 for_each_possible_cpu(cpu) {
3646 struct sock *sk;
3647
3648 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3649 IPPROTO_TCP, &init_net);
3650 if (res)
3651 panic("Failed to create the TCP control socket.\n");
3652 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3653
3654 /* Please enforce IP_DF and IPID==0 for RST and
3655 * ACK sent in SYN-RECV and TIME-WAIT state.
3656 */
3657 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3658
3659 sk->sk_clockid = CLOCK_MONOTONIC;
3660
3661 per_cpu(ipv4_tcp_sk.sock, cpu) = sk;
3662 }
3663 if (register_pernet_subsys(&tcp_sk_ops))
3664 panic("Failed to create the TCP control socket.\n");
3665
3666#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3667 bpf_iter_register();
3668#endif
3669}