xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision 239480ab)
1 /*
2  *	TCP over IPv6
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Based on:
9  *	linux/net/ipv4/tcp.c
10  *	linux/net/ipv4/tcp_input.c
11  *	linux/net/ipv4/tcp_output.c
12  *
13  *	Fixes:
14  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
15  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
16  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
17  *					a single port at the same time.
18  *	YOSHIFUJI Hideaki @USAGI:	convert /proc/net/tcp6 to seq_file.
19  *
20  *	This program is free software; you can redistribute it and/or
21  *      modify it under the terms of the GNU General Public License
22  *      as published by the Free Software Foundation; either version
23  *      2 of the License, or (at your option) any later version.
24  */
25 
26 #include <linux/bottom_half.h>
27 #include <linux/module.h>
28 #include <linux/errno.h>
29 #include <linux/types.h>
30 #include <linux/socket.h>
31 #include <linux/sockios.h>
32 #include <linux/net.h>
33 #include <linux/jiffies.h>
34 #include <linux/in.h>
35 #include <linux/in6.h>
36 #include <linux/netdevice.h>
37 #include <linux/init.h>
38 #include <linux/jhash.h>
39 #include <linux/ipsec.h>
40 #include <linux/times.h>
41 #include <linux/slab.h>
42 #include <linux/uaccess.h>
43 #include <linux/ipv6.h>
44 #include <linux/icmpv6.h>
45 #include <linux/random.h>
46 
47 #include <net/tcp.h>
48 #include <net/ndisc.h>
49 #include <net/inet6_hashtables.h>
50 #include <net/inet6_connection_sock.h>
51 #include <net/ipv6.h>
52 #include <net/transp_v6.h>
53 #include <net/addrconf.h>
54 #include <net/ip6_route.h>
55 #include <net/ip6_checksum.h>
56 #include <net/inet_ecn.h>
57 #include <net/protocol.h>
58 #include <net/xfrm.h>
59 #include <net/snmp.h>
60 #include <net/dsfield.h>
61 #include <net/timewait_sock.h>
62 #include <net/inet_common.h>
63 #include <net/secure_seq.h>
64 #include <net/busy_poll.h>
65 
66 #include <linux/proc_fs.h>
67 #include <linux/seq_file.h>
68 
69 #include <crypto/hash.h>
70 #include <linux/scatterlist.h>
71 
72 static void	tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
73 static void	tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
74 				      struct request_sock *req);
75 
76 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
77 
78 static const struct inet_connection_sock_af_ops ipv6_mapped;
79 static const struct inet_connection_sock_af_ops ipv6_specific;
80 #ifdef CONFIG_TCP_MD5SIG
81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
83 #else
84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
85 						   const struct in6_addr *addr)
86 {
87 	return NULL;
88 }
89 #endif
90 
91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
92 {
93 	struct dst_entry *dst = skb_dst(skb);
94 
95 	if (dst && dst_hold_safe(dst)) {
96 		const struct rt6_info *rt = (const struct rt6_info *)dst;
97 
98 		sk->sk_rx_dst = dst;
99 		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
100 		inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
101 	}
102 }
103 
104 static u32 tcp_v6_init_seq(const struct sk_buff *skb)
105 {
106 	return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32,
107 				ipv6_hdr(skb)->saddr.s6_addr32,
108 				tcp_hdr(skb)->dest,
109 				tcp_hdr(skb)->source);
110 }
111 
112 static u32 tcp_v6_init_ts_off(const struct sk_buff *skb)
113 {
114 	return secure_tcpv6_ts_off(ipv6_hdr(skb)->daddr.s6_addr32,
115 				   ipv6_hdr(skb)->saddr.s6_addr32);
116 }
117 
118 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
119 			  int addr_len)
120 {
121 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
122 	struct inet_sock *inet = inet_sk(sk);
123 	struct inet_connection_sock *icsk = inet_csk(sk);
124 	struct ipv6_pinfo *np = inet6_sk(sk);
125 	struct tcp_sock *tp = tcp_sk(sk);
126 	struct in6_addr *saddr = NULL, *final_p, final;
127 	struct ipv6_txoptions *opt;
128 	struct flowi6 fl6;
129 	struct dst_entry *dst;
130 	int addr_type;
131 	int err;
132 	struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
133 
134 	if (addr_len < SIN6_LEN_RFC2133)
135 		return -EINVAL;
136 
137 	if (usin->sin6_family != AF_INET6)
138 		return -EAFNOSUPPORT;
139 
140 	memset(&fl6, 0, sizeof(fl6));
141 
142 	if (np->sndflow) {
143 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
144 		IP6_ECN_flow_init(fl6.flowlabel);
145 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
146 			struct ip6_flowlabel *flowlabel;
147 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
148 			if (!flowlabel)
149 				return -EINVAL;
150 			fl6_sock_release(flowlabel);
151 		}
152 	}
153 
154 	/*
155 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
156 	 */
157 
158 	if (ipv6_addr_any(&usin->sin6_addr)) {
159 		if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
160 			ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
161 					       &usin->sin6_addr);
162 		else
163 			usin->sin6_addr = in6addr_loopback;
164 	}
165 
166 	addr_type = ipv6_addr_type(&usin->sin6_addr);
167 
168 	if (addr_type & IPV6_ADDR_MULTICAST)
169 		return -ENETUNREACH;
170 
171 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
172 		if (addr_len >= sizeof(struct sockaddr_in6) &&
173 		    usin->sin6_scope_id) {
174 			/* If interface is set while binding, indices
175 			 * must coincide.
176 			 */
177 			if (sk->sk_bound_dev_if &&
178 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
179 				return -EINVAL;
180 
181 			sk->sk_bound_dev_if = usin->sin6_scope_id;
182 		}
183 
184 		/* Connect to link-local address requires an interface */
185 		if (!sk->sk_bound_dev_if)
186 			return -EINVAL;
187 	}
188 
189 	if (tp->rx_opt.ts_recent_stamp &&
190 	    !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
191 		tp->rx_opt.ts_recent = 0;
192 		tp->rx_opt.ts_recent_stamp = 0;
193 		tp->write_seq = 0;
194 	}
195 
196 	sk->sk_v6_daddr = usin->sin6_addr;
197 	np->flow_label = fl6.flowlabel;
198 
199 	/*
200 	 *	TCP over IPv4
201 	 */
202 
203 	if (addr_type & IPV6_ADDR_MAPPED) {
204 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
205 		struct sockaddr_in sin;
206 
207 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
208 
209 		if (__ipv6_only_sock(sk))
210 			return -ENETUNREACH;
211 
212 		sin.sin_family = AF_INET;
213 		sin.sin_port = usin->sin6_port;
214 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
215 
216 		icsk->icsk_af_ops = &ipv6_mapped;
217 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
218 #ifdef CONFIG_TCP_MD5SIG
219 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
220 #endif
221 
222 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
223 
224 		if (err) {
225 			icsk->icsk_ext_hdr_len = exthdrlen;
226 			icsk->icsk_af_ops = &ipv6_specific;
227 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
228 #ifdef CONFIG_TCP_MD5SIG
229 			tp->af_specific = &tcp_sock_ipv6_specific;
230 #endif
231 			goto failure;
232 		}
233 		np->saddr = sk->sk_v6_rcv_saddr;
234 
235 		return err;
236 	}
237 
238 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
239 		saddr = &sk->sk_v6_rcv_saddr;
240 
241 	fl6.flowi6_proto = IPPROTO_TCP;
242 	fl6.daddr = sk->sk_v6_daddr;
243 	fl6.saddr = saddr ? *saddr : np->saddr;
244 	fl6.flowi6_oif = sk->sk_bound_dev_if;
245 	fl6.flowi6_mark = sk->sk_mark;
246 	fl6.fl6_dport = usin->sin6_port;
247 	fl6.fl6_sport = inet->inet_sport;
248 	fl6.flowi6_uid = sk->sk_uid;
249 
250 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
251 	final_p = fl6_update_dst(&fl6, opt, &final);
252 
253 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
254 
255 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
256 	if (IS_ERR(dst)) {
257 		err = PTR_ERR(dst);
258 		goto failure;
259 	}
260 
261 	if (!saddr) {
262 		saddr = &fl6.saddr;
263 		sk->sk_v6_rcv_saddr = *saddr;
264 	}
265 
266 	/* set the source address */
267 	np->saddr = *saddr;
268 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
269 
270 	sk->sk_gso_type = SKB_GSO_TCPV6;
271 	ip6_dst_store(sk, dst, NULL, NULL);
272 
273 	icsk->icsk_ext_hdr_len = 0;
274 	if (opt)
275 		icsk->icsk_ext_hdr_len = opt->opt_flen +
276 					 opt->opt_nflen;
277 
278 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
279 
280 	inet->inet_dport = usin->sin6_port;
281 
282 	tcp_set_state(sk, TCP_SYN_SENT);
283 	err = inet6_hash_connect(tcp_death_row, sk);
284 	if (err)
285 		goto late_failure;
286 
287 	sk_set_txhash(sk);
288 
289 	if (likely(!tp->repair)) {
290 		if (!tp->write_seq)
291 			tp->write_seq = secure_tcpv6_seq(np->saddr.s6_addr32,
292 							 sk->sk_v6_daddr.s6_addr32,
293 							 inet->inet_sport,
294 							 inet->inet_dport);
295 		tp->tsoffset = secure_tcpv6_ts_off(np->saddr.s6_addr32,
296 						   sk->sk_v6_daddr.s6_addr32);
297 	}
298 
299 	if (tcp_fastopen_defer_connect(sk, &err))
300 		return err;
301 	if (err)
302 		goto late_failure;
303 
304 	err = tcp_connect(sk);
305 	if (err)
306 		goto late_failure;
307 
308 	return 0;
309 
310 late_failure:
311 	tcp_set_state(sk, TCP_CLOSE);
312 failure:
313 	inet->inet_dport = 0;
314 	sk->sk_route_caps = 0;
315 	return err;
316 }
317 
318 static void tcp_v6_mtu_reduced(struct sock *sk)
319 {
320 	struct dst_entry *dst;
321 
322 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
323 		return;
324 
325 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
326 	if (!dst)
327 		return;
328 
329 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
330 		tcp_sync_mss(sk, dst_mtu(dst));
331 		tcp_simple_retransmit(sk);
332 	}
333 }
334 
335 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
336 		u8 type, u8 code, int offset, __be32 info)
337 {
338 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
339 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
340 	struct net *net = dev_net(skb->dev);
341 	struct request_sock *fastopen;
342 	struct ipv6_pinfo *np;
343 	struct tcp_sock *tp;
344 	__u32 seq, snd_una;
345 	struct sock *sk;
346 	bool fatal;
347 	int err;
348 
349 	sk = __inet6_lookup_established(net, &tcp_hashinfo,
350 					&hdr->daddr, th->dest,
351 					&hdr->saddr, ntohs(th->source),
352 					skb->dev->ifindex);
353 
354 	if (!sk) {
355 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
356 				  ICMP6_MIB_INERRORS);
357 		return;
358 	}
359 
360 	if (sk->sk_state == TCP_TIME_WAIT) {
361 		inet_twsk_put(inet_twsk(sk));
362 		return;
363 	}
364 	seq = ntohl(th->seq);
365 	fatal = icmpv6_err_convert(type, code, &err);
366 	if (sk->sk_state == TCP_NEW_SYN_RECV)
367 		return tcp_req_err(sk, seq, fatal);
368 
369 	bh_lock_sock(sk);
370 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
371 		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
372 
373 	if (sk->sk_state == TCP_CLOSE)
374 		goto out;
375 
376 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
377 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
378 		goto out;
379 	}
380 
381 	tp = tcp_sk(sk);
382 	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
383 	fastopen = tp->fastopen_rsk;
384 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
385 	if (sk->sk_state != TCP_LISTEN &&
386 	    !between(seq, snd_una, tp->snd_nxt)) {
387 		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
388 		goto out;
389 	}
390 
391 	np = inet6_sk(sk);
392 
393 	if (type == NDISC_REDIRECT) {
394 		if (!sock_owned_by_user(sk)) {
395 			struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
396 
397 			if (dst)
398 				dst->ops->redirect(dst, sk, skb);
399 		}
400 		goto out;
401 	}
402 
403 	if (type == ICMPV6_PKT_TOOBIG) {
404 		/* We are not interested in TCP_LISTEN and open_requests
405 		 * (SYN-ACKs send out by Linux are always <576bytes so
406 		 * they should go through unfragmented).
407 		 */
408 		if (sk->sk_state == TCP_LISTEN)
409 			goto out;
410 
411 		if (!ip6_sk_accept_pmtu(sk))
412 			goto out;
413 
414 		tp->mtu_info = ntohl(info);
415 		if (!sock_owned_by_user(sk))
416 			tcp_v6_mtu_reduced(sk);
417 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
418 					   &sk->sk_tsq_flags))
419 			sock_hold(sk);
420 		goto out;
421 	}
422 
423 
424 	/* Might be for an request_sock */
425 	switch (sk->sk_state) {
426 	case TCP_SYN_SENT:
427 	case TCP_SYN_RECV:
428 		/* Only in fast or simultaneous open. If a fast open socket is
429 		 * is already accepted it is treated as a connected one below.
430 		 */
431 		if (fastopen && !fastopen->sk)
432 			break;
433 
434 		if (!sock_owned_by_user(sk)) {
435 			sk->sk_err = err;
436 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
437 
438 			tcp_done(sk);
439 		} else
440 			sk->sk_err_soft = err;
441 		goto out;
442 	}
443 
444 	if (!sock_owned_by_user(sk) && np->recverr) {
445 		sk->sk_err = err;
446 		sk->sk_error_report(sk);
447 	} else
448 		sk->sk_err_soft = err;
449 
450 out:
451 	bh_unlock_sock(sk);
452 	sock_put(sk);
453 }
454 
455 
456 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
457 			      struct flowi *fl,
458 			      struct request_sock *req,
459 			      struct tcp_fastopen_cookie *foc,
460 			      enum tcp_synack_type synack_type)
461 {
462 	struct inet_request_sock *ireq = inet_rsk(req);
463 	struct ipv6_pinfo *np = inet6_sk(sk);
464 	struct ipv6_txoptions *opt;
465 	struct flowi6 *fl6 = &fl->u.ip6;
466 	struct sk_buff *skb;
467 	int err = -ENOMEM;
468 
469 	/* First, grab a route. */
470 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
471 					       IPPROTO_TCP)) == NULL)
472 		goto done;
473 
474 	skb = tcp_make_synack(sk, dst, req, foc, synack_type);
475 
476 	if (skb) {
477 		__tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
478 				    &ireq->ir_v6_rmt_addr);
479 
480 		fl6->daddr = ireq->ir_v6_rmt_addr;
481 		if (np->repflow && ireq->pktopts)
482 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
483 
484 		rcu_read_lock();
485 		opt = ireq->ipv6_opt;
486 		if (!opt)
487 			opt = rcu_dereference(np->opt);
488 		err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt, np->tclass);
489 		rcu_read_unlock();
490 		err = net_xmit_eval(err);
491 	}
492 
493 done:
494 	return err;
495 }
496 
497 
498 static void tcp_v6_reqsk_destructor(struct request_sock *req)
499 {
500 	kfree(inet_rsk(req)->ipv6_opt);
501 	kfree_skb(inet_rsk(req)->pktopts);
502 }
503 
504 #ifdef CONFIG_TCP_MD5SIG
505 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
506 						   const struct in6_addr *addr)
507 {
508 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
509 }
510 
511 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
512 						const struct sock *addr_sk)
513 {
514 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
515 }
516 
517 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
518 				 int optlen)
519 {
520 	struct tcp_md5sig cmd;
521 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
522 
523 	if (optlen < sizeof(cmd))
524 		return -EINVAL;
525 
526 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
527 		return -EFAULT;
528 
529 	if (sin6->sin6_family != AF_INET6)
530 		return -EINVAL;
531 
532 	if (!cmd.tcpm_keylen) {
533 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
534 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
535 					      AF_INET);
536 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
537 				      AF_INET6);
538 	}
539 
540 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
541 		return -EINVAL;
542 
543 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
544 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
545 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
546 
547 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
548 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
549 }
550 
551 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
552 				   const struct in6_addr *daddr,
553 				   const struct in6_addr *saddr,
554 				   const struct tcphdr *th, int nbytes)
555 {
556 	struct tcp6_pseudohdr *bp;
557 	struct scatterlist sg;
558 	struct tcphdr *_th;
559 
560 	bp = hp->scratch;
561 	/* 1. TCP pseudo-header (RFC2460) */
562 	bp->saddr = *saddr;
563 	bp->daddr = *daddr;
564 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
565 	bp->len = cpu_to_be32(nbytes);
566 
567 	_th = (struct tcphdr *)(bp + 1);
568 	memcpy(_th, th, sizeof(*th));
569 	_th->check = 0;
570 
571 	sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
572 	ahash_request_set_crypt(hp->md5_req, &sg, NULL,
573 				sizeof(*bp) + sizeof(*th));
574 	return crypto_ahash_update(hp->md5_req);
575 }
576 
577 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
578 			       const struct in6_addr *daddr, struct in6_addr *saddr,
579 			       const struct tcphdr *th)
580 {
581 	struct tcp_md5sig_pool *hp;
582 	struct ahash_request *req;
583 
584 	hp = tcp_get_md5sig_pool();
585 	if (!hp)
586 		goto clear_hash_noput;
587 	req = hp->md5_req;
588 
589 	if (crypto_ahash_init(req))
590 		goto clear_hash;
591 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
592 		goto clear_hash;
593 	if (tcp_md5_hash_key(hp, key))
594 		goto clear_hash;
595 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
596 	if (crypto_ahash_final(req))
597 		goto clear_hash;
598 
599 	tcp_put_md5sig_pool();
600 	return 0;
601 
602 clear_hash:
603 	tcp_put_md5sig_pool();
604 clear_hash_noput:
605 	memset(md5_hash, 0, 16);
606 	return 1;
607 }
608 
609 static int tcp_v6_md5_hash_skb(char *md5_hash,
610 			       const struct tcp_md5sig_key *key,
611 			       const struct sock *sk,
612 			       const struct sk_buff *skb)
613 {
614 	const struct in6_addr *saddr, *daddr;
615 	struct tcp_md5sig_pool *hp;
616 	struct ahash_request *req;
617 	const struct tcphdr *th = tcp_hdr(skb);
618 
619 	if (sk) { /* valid for establish/request sockets */
620 		saddr = &sk->sk_v6_rcv_saddr;
621 		daddr = &sk->sk_v6_daddr;
622 	} else {
623 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
624 		saddr = &ip6h->saddr;
625 		daddr = &ip6h->daddr;
626 	}
627 
628 	hp = tcp_get_md5sig_pool();
629 	if (!hp)
630 		goto clear_hash_noput;
631 	req = hp->md5_req;
632 
633 	if (crypto_ahash_init(req))
634 		goto clear_hash;
635 
636 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
637 		goto clear_hash;
638 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
639 		goto clear_hash;
640 	if (tcp_md5_hash_key(hp, key))
641 		goto clear_hash;
642 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
643 	if (crypto_ahash_final(req))
644 		goto clear_hash;
645 
646 	tcp_put_md5sig_pool();
647 	return 0;
648 
649 clear_hash:
650 	tcp_put_md5sig_pool();
651 clear_hash_noput:
652 	memset(md5_hash, 0, 16);
653 	return 1;
654 }
655 
656 #endif
657 
658 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
659 				    const struct sk_buff *skb)
660 {
661 #ifdef CONFIG_TCP_MD5SIG
662 	const __u8 *hash_location = NULL;
663 	struct tcp_md5sig_key *hash_expected;
664 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
665 	const struct tcphdr *th = tcp_hdr(skb);
666 	int genhash;
667 	u8 newhash[16];
668 
669 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
670 	hash_location = tcp_parse_md5sig_option(th);
671 
672 	/* We've parsed the options - do we have a hash? */
673 	if (!hash_expected && !hash_location)
674 		return false;
675 
676 	if (hash_expected && !hash_location) {
677 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
678 		return true;
679 	}
680 
681 	if (!hash_expected && hash_location) {
682 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
683 		return true;
684 	}
685 
686 	/* check the signature */
687 	genhash = tcp_v6_md5_hash_skb(newhash,
688 				      hash_expected,
689 				      NULL, skb);
690 
691 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
692 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
693 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
694 				     genhash ? "failed" : "mismatch",
695 				     &ip6h->saddr, ntohs(th->source),
696 				     &ip6h->daddr, ntohs(th->dest));
697 		return true;
698 	}
699 #endif
700 	return false;
701 }
702 
703 static void tcp_v6_init_req(struct request_sock *req,
704 			    const struct sock *sk_listener,
705 			    struct sk_buff *skb)
706 {
707 	struct inet_request_sock *ireq = inet_rsk(req);
708 	const struct ipv6_pinfo *np = inet6_sk(sk_listener);
709 
710 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
711 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
712 
713 	/* So that link locals have meaning */
714 	if (!sk_listener->sk_bound_dev_if &&
715 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
716 		ireq->ir_iif = tcp_v6_iif(skb);
717 
718 	if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
719 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
720 	     np->rxopt.bits.rxinfo ||
721 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
722 	     np->rxopt.bits.rxohlim || np->repflow)) {
723 		atomic_inc(&skb->users);
724 		ireq->pktopts = skb;
725 	}
726 }
727 
728 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
729 					  struct flowi *fl,
730 					  const struct request_sock *req)
731 {
732 	return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
733 }
734 
735 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
736 	.family		=	AF_INET6,
737 	.obj_size	=	sizeof(struct tcp6_request_sock),
738 	.rtx_syn_ack	=	tcp_rtx_synack,
739 	.send_ack	=	tcp_v6_reqsk_send_ack,
740 	.destructor	=	tcp_v6_reqsk_destructor,
741 	.send_reset	=	tcp_v6_send_reset,
742 	.syn_ack_timeout =	tcp_syn_ack_timeout,
743 };
744 
745 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
746 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
747 				sizeof(struct ipv6hdr),
748 #ifdef CONFIG_TCP_MD5SIG
749 	.req_md5_lookup	=	tcp_v6_md5_lookup,
750 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
751 #endif
752 	.init_req	=	tcp_v6_init_req,
753 #ifdef CONFIG_SYN_COOKIES
754 	.cookie_init_seq =	cookie_v6_init_sequence,
755 #endif
756 	.route_req	=	tcp_v6_route_req,
757 	.init_seq	=	tcp_v6_init_seq,
758 	.init_ts_off	=	tcp_v6_init_ts_off,
759 	.send_synack	=	tcp_v6_send_synack,
760 };
761 
762 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
763 				 u32 ack, u32 win, u32 tsval, u32 tsecr,
764 				 int oif, struct tcp_md5sig_key *key, int rst,
765 				 u8 tclass, __be32 label)
766 {
767 	const struct tcphdr *th = tcp_hdr(skb);
768 	struct tcphdr *t1;
769 	struct sk_buff *buff;
770 	struct flowi6 fl6;
771 	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
772 	struct sock *ctl_sk = net->ipv6.tcp_sk;
773 	unsigned int tot_len = sizeof(struct tcphdr);
774 	struct dst_entry *dst;
775 	__be32 *topt;
776 
777 	if (tsecr)
778 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
779 #ifdef CONFIG_TCP_MD5SIG
780 	if (key)
781 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
782 #endif
783 
784 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
785 			 GFP_ATOMIC);
786 	if (!buff)
787 		return;
788 
789 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
790 
791 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
792 	skb_reset_transport_header(buff);
793 
794 	/* Swap the send and the receive. */
795 	memset(t1, 0, sizeof(*t1));
796 	t1->dest = th->source;
797 	t1->source = th->dest;
798 	t1->doff = tot_len / 4;
799 	t1->seq = htonl(seq);
800 	t1->ack_seq = htonl(ack);
801 	t1->ack = !rst || !th->ack;
802 	t1->rst = rst;
803 	t1->window = htons(win);
804 
805 	topt = (__be32 *)(t1 + 1);
806 
807 	if (tsecr) {
808 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
809 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
810 		*topt++ = htonl(tsval);
811 		*topt++ = htonl(tsecr);
812 	}
813 
814 #ifdef CONFIG_TCP_MD5SIG
815 	if (key) {
816 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
817 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
818 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
819 				    &ipv6_hdr(skb)->saddr,
820 				    &ipv6_hdr(skb)->daddr, t1);
821 	}
822 #endif
823 
824 	memset(&fl6, 0, sizeof(fl6));
825 	fl6.daddr = ipv6_hdr(skb)->saddr;
826 	fl6.saddr = ipv6_hdr(skb)->daddr;
827 	fl6.flowlabel = label;
828 
829 	buff->ip_summed = CHECKSUM_PARTIAL;
830 	buff->csum = 0;
831 
832 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
833 
834 	fl6.flowi6_proto = IPPROTO_TCP;
835 	if (rt6_need_strict(&fl6.daddr) && !oif)
836 		fl6.flowi6_oif = tcp_v6_iif(skb);
837 	else {
838 		if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
839 			oif = skb->skb_iif;
840 
841 		fl6.flowi6_oif = oif;
842 	}
843 
844 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
845 	fl6.fl6_dport = t1->dest;
846 	fl6.fl6_sport = t1->source;
847 	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
848 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
849 
850 	/* Pass a socket to ip6_dst_lookup either it is for RST
851 	 * Underlying function will use this to retrieve the network
852 	 * namespace
853 	 */
854 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
855 	if (!IS_ERR(dst)) {
856 		skb_dst_set(buff, dst);
857 		ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, tclass);
858 		TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
859 		if (rst)
860 			TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
861 		return;
862 	}
863 
864 	kfree_skb(buff);
865 }
866 
867 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
868 {
869 	const struct tcphdr *th = tcp_hdr(skb);
870 	u32 seq = 0, ack_seq = 0;
871 	struct tcp_md5sig_key *key = NULL;
872 #ifdef CONFIG_TCP_MD5SIG
873 	const __u8 *hash_location = NULL;
874 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
875 	unsigned char newhash[16];
876 	int genhash;
877 	struct sock *sk1 = NULL;
878 #endif
879 	int oif;
880 
881 	if (th->rst)
882 		return;
883 
884 	/* If sk not NULL, it means we did a successful lookup and incoming
885 	 * route had to be correct. prequeue might have dropped our dst.
886 	 */
887 	if (!sk && !ipv6_unicast_destination(skb))
888 		return;
889 
890 #ifdef CONFIG_TCP_MD5SIG
891 	rcu_read_lock();
892 	hash_location = tcp_parse_md5sig_option(th);
893 	if (sk && sk_fullsock(sk)) {
894 		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
895 	} else if (hash_location) {
896 		/*
897 		 * active side is lost. Try to find listening socket through
898 		 * source port, and then find md5 key through listening socket.
899 		 * we are not loose security here:
900 		 * Incoming packet is checked with md5 hash with finding key,
901 		 * no RST generated if md5 hash doesn't match.
902 		 */
903 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
904 					   &tcp_hashinfo, NULL, 0,
905 					   &ipv6h->saddr,
906 					   th->source, &ipv6h->daddr,
907 					   ntohs(th->source), tcp_v6_iif(skb));
908 		if (!sk1)
909 			goto out;
910 
911 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
912 		if (!key)
913 			goto out;
914 
915 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
916 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
917 			goto out;
918 	}
919 #endif
920 
921 	if (th->ack)
922 		seq = ntohl(th->ack_seq);
923 	else
924 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
925 			  (th->doff << 2);
926 
927 	oif = sk ? sk->sk_bound_dev_if : 0;
928 	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
929 
930 #ifdef CONFIG_TCP_MD5SIG
931 out:
932 	rcu_read_unlock();
933 #endif
934 }
935 
936 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
937 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
938 			    struct tcp_md5sig_key *key, u8 tclass,
939 			    __be32 label)
940 {
941 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
942 			     tclass, label);
943 }
944 
945 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
946 {
947 	struct inet_timewait_sock *tw = inet_twsk(sk);
948 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
949 
950 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
951 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
952 			tcp_time_stamp + tcptw->tw_ts_offset,
953 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
954 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
955 
956 	inet_twsk_put(tw);
957 }
958 
959 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
960 				  struct request_sock *req)
961 {
962 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
963 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
964 	 */
965 	/* RFC 7323 2.3
966 	 * The window field (SEG.WND) of every outgoing segment, with the
967 	 * exception of <SYN> segments, MUST be right-shifted by
968 	 * Rcv.Wind.Shift bits:
969 	 */
970 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
971 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
972 			tcp_rsk(req)->rcv_nxt,
973 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
974 			tcp_time_stamp + tcp_rsk(req)->ts_off,
975 			req->ts_recent, sk->sk_bound_dev_if,
976 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
977 			0, 0);
978 }
979 
980 
981 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
982 {
983 #ifdef CONFIG_SYN_COOKIES
984 	const struct tcphdr *th = tcp_hdr(skb);
985 
986 	if (!th->syn)
987 		sk = cookie_v6_check(sk, skb);
988 #endif
989 	return sk;
990 }
991 
992 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
993 {
994 	if (skb->protocol == htons(ETH_P_IP))
995 		return tcp_v4_conn_request(sk, skb);
996 
997 	if (!ipv6_unicast_destination(skb))
998 		goto drop;
999 
1000 	return tcp_conn_request(&tcp6_request_sock_ops,
1001 				&tcp_request_sock_ipv6_ops, sk, skb);
1002 
1003 drop:
1004 	tcp_listendrop(sk);
1005 	return 0; /* don't send reset */
1006 }
1007 
1008 static void tcp_v6_restore_cb(struct sk_buff *skb)
1009 {
1010 	/* We need to move header back to the beginning if xfrm6_policy_check()
1011 	 * and tcp_v6_fill_cb() are going to be called again.
1012 	 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1013 	 */
1014 	memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1015 		sizeof(struct inet6_skb_parm));
1016 }
1017 
1018 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1019 					 struct request_sock *req,
1020 					 struct dst_entry *dst,
1021 					 struct request_sock *req_unhash,
1022 					 bool *own_req)
1023 {
1024 	struct inet_request_sock *ireq;
1025 	struct ipv6_pinfo *newnp;
1026 	const struct ipv6_pinfo *np = inet6_sk(sk);
1027 	struct ipv6_txoptions *opt;
1028 	struct tcp6_sock *newtcp6sk;
1029 	struct inet_sock *newinet;
1030 	struct tcp_sock *newtp;
1031 	struct sock *newsk;
1032 #ifdef CONFIG_TCP_MD5SIG
1033 	struct tcp_md5sig_key *key;
1034 #endif
1035 	struct flowi6 fl6;
1036 
1037 	if (skb->protocol == htons(ETH_P_IP)) {
1038 		/*
1039 		 *	v6 mapped
1040 		 */
1041 
1042 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1043 					     req_unhash, own_req);
1044 
1045 		if (!newsk)
1046 			return NULL;
1047 
1048 		newtcp6sk = (struct tcp6_sock *)newsk;
1049 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1050 
1051 		newinet = inet_sk(newsk);
1052 		newnp = inet6_sk(newsk);
1053 		newtp = tcp_sk(newsk);
1054 
1055 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1056 
1057 		newnp->saddr = newsk->sk_v6_rcv_saddr;
1058 
1059 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1060 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1061 #ifdef CONFIG_TCP_MD5SIG
1062 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1063 #endif
1064 
1065 		newnp->ipv6_ac_list = NULL;
1066 		newnp->ipv6_fl_list = NULL;
1067 		newnp->pktoptions  = NULL;
1068 		newnp->opt	   = NULL;
1069 		newnp->mcast_oif   = tcp_v6_iif(skb);
1070 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1071 		newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1072 		if (np->repflow)
1073 			newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1074 
1075 		/*
1076 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1077 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1078 		 * that function for the gory details. -acme
1079 		 */
1080 
1081 		/* It is tricky place. Until this moment IPv4 tcp
1082 		   worked with IPv6 icsk.icsk_af_ops.
1083 		   Sync it now.
1084 		 */
1085 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1086 
1087 		return newsk;
1088 	}
1089 
1090 	ireq = inet_rsk(req);
1091 
1092 	if (sk_acceptq_is_full(sk))
1093 		goto out_overflow;
1094 
1095 	if (!dst) {
1096 		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1097 		if (!dst)
1098 			goto out;
1099 	}
1100 
1101 	newsk = tcp_create_openreq_child(sk, req, skb);
1102 	if (!newsk)
1103 		goto out_nonewsk;
1104 
1105 	/*
1106 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1107 	 * count here, tcp_create_openreq_child now does this for us, see the
1108 	 * comment in that function for the gory details. -acme
1109 	 */
1110 
1111 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1112 	ip6_dst_store(newsk, dst, NULL, NULL);
1113 	inet6_sk_rx_dst_set(newsk, skb);
1114 
1115 	newtcp6sk = (struct tcp6_sock *)newsk;
1116 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1117 
1118 	newtp = tcp_sk(newsk);
1119 	newinet = inet_sk(newsk);
1120 	newnp = inet6_sk(newsk);
1121 
1122 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1123 
1124 	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1125 	newnp->saddr = ireq->ir_v6_loc_addr;
1126 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1127 	newsk->sk_bound_dev_if = ireq->ir_iif;
1128 
1129 	/* Now IPv6 options...
1130 
1131 	   First: no IPv4 options.
1132 	 */
1133 	newinet->inet_opt = NULL;
1134 	newnp->ipv6_ac_list = NULL;
1135 	newnp->ipv6_fl_list = NULL;
1136 
1137 	/* Clone RX bits */
1138 	newnp->rxopt.all = np->rxopt.all;
1139 
1140 	newnp->pktoptions = NULL;
1141 	newnp->opt	  = NULL;
1142 	newnp->mcast_oif  = tcp_v6_iif(skb);
1143 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1144 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1145 	if (np->repflow)
1146 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1147 
1148 	/* Clone native IPv6 options from listening socket (if any)
1149 
1150 	   Yes, keeping reference count would be much more clever,
1151 	   but we make one more one thing there: reattach optmem
1152 	   to newsk.
1153 	 */
1154 	opt = ireq->ipv6_opt;
1155 	if (!opt)
1156 		opt = rcu_dereference(np->opt);
1157 	if (opt) {
1158 		opt = ipv6_dup_options(newsk, opt);
1159 		RCU_INIT_POINTER(newnp->opt, opt);
1160 	}
1161 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1162 	if (opt)
1163 		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1164 						    opt->opt_flen;
1165 
1166 	tcp_ca_openreq_child(newsk, dst);
1167 
1168 	tcp_sync_mss(newsk, dst_mtu(dst));
1169 	newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1170 
1171 	tcp_initialize_rcv_mss(newsk);
1172 
1173 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1174 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1175 
1176 #ifdef CONFIG_TCP_MD5SIG
1177 	/* Copy over the MD5 key from the original socket */
1178 	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1179 	if (key) {
1180 		/* We're using one, so create a matching key
1181 		 * on the newsk structure. If we fail to get
1182 		 * memory, then we end up not copying the key
1183 		 * across. Shucks.
1184 		 */
1185 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1186 			       AF_INET6, key->key, key->keylen,
1187 			       sk_gfp_mask(sk, GFP_ATOMIC));
1188 	}
1189 #endif
1190 
1191 	if (__inet_inherit_port(sk, newsk) < 0) {
1192 		inet_csk_prepare_forced_close(newsk);
1193 		tcp_done(newsk);
1194 		goto out;
1195 	}
1196 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1197 	if (*own_req) {
1198 		tcp_move_syn(newtp, req);
1199 
1200 		/* Clone pktoptions received with SYN, if we own the req */
1201 		if (ireq->pktopts) {
1202 			newnp->pktoptions = skb_clone(ireq->pktopts,
1203 						      sk_gfp_mask(sk, GFP_ATOMIC));
1204 			consume_skb(ireq->pktopts);
1205 			ireq->pktopts = NULL;
1206 			if (newnp->pktoptions) {
1207 				tcp_v6_restore_cb(newnp->pktoptions);
1208 				skb_set_owner_r(newnp->pktoptions, newsk);
1209 			}
1210 		}
1211 	}
1212 
1213 	return newsk;
1214 
1215 out_overflow:
1216 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1217 out_nonewsk:
1218 	dst_release(dst);
1219 out:
1220 	tcp_listendrop(sk);
1221 	return NULL;
1222 }
1223 
1224 /* The socket must have it's spinlock held when we get
1225  * here, unless it is a TCP_LISTEN socket.
1226  *
1227  * We have a potential double-lock case here, so even when
1228  * doing backlog processing we use the BH locking scheme.
1229  * This is because we cannot sleep with the original spinlock
1230  * held.
1231  */
1232 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1233 {
1234 	struct ipv6_pinfo *np = inet6_sk(sk);
1235 	struct tcp_sock *tp;
1236 	struct sk_buff *opt_skb = NULL;
1237 
1238 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1239 	   goes to IPv4 receive handler and backlogged.
1240 	   From backlog it always goes here. Kerboom...
1241 	   Fortunately, tcp_rcv_established and rcv_established
1242 	   handle them correctly, but it is not case with
1243 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1244 	 */
1245 
1246 	if (skb->protocol == htons(ETH_P_IP))
1247 		return tcp_v4_do_rcv(sk, skb);
1248 
1249 	if (tcp_filter(sk, skb))
1250 		goto discard;
1251 
1252 	/*
1253 	 *	socket locking is here for SMP purposes as backlog rcv
1254 	 *	is currently called with bh processing disabled.
1255 	 */
1256 
1257 	/* Do Stevens' IPV6_PKTOPTIONS.
1258 
1259 	   Yes, guys, it is the only place in our code, where we
1260 	   may make it not affecting IPv4.
1261 	   The rest of code is protocol independent,
1262 	   and I do not like idea to uglify IPv4.
1263 
1264 	   Actually, all the idea behind IPV6_PKTOPTIONS
1265 	   looks not very well thought. For now we latch
1266 	   options, received in the last packet, enqueued
1267 	   by tcp. Feel free to propose better solution.
1268 					       --ANK (980728)
1269 	 */
1270 	if (np->rxopt.all)
1271 		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1272 
1273 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1274 		struct dst_entry *dst = sk->sk_rx_dst;
1275 
1276 		sock_rps_save_rxhash(sk, skb);
1277 		sk_mark_napi_id(sk, skb);
1278 		if (dst) {
1279 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1280 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1281 				dst_release(dst);
1282 				sk->sk_rx_dst = NULL;
1283 			}
1284 		}
1285 
1286 		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1287 		if (opt_skb)
1288 			goto ipv6_pktoptions;
1289 		return 0;
1290 	}
1291 
1292 	if (tcp_checksum_complete(skb))
1293 		goto csum_err;
1294 
1295 	if (sk->sk_state == TCP_LISTEN) {
1296 		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1297 
1298 		if (!nsk)
1299 			goto discard;
1300 
1301 		if (nsk != sk) {
1302 			if (tcp_child_process(sk, nsk, skb))
1303 				goto reset;
1304 			if (opt_skb)
1305 				__kfree_skb(opt_skb);
1306 			return 0;
1307 		}
1308 	} else
1309 		sock_rps_save_rxhash(sk, skb);
1310 
1311 	if (tcp_rcv_state_process(sk, skb))
1312 		goto reset;
1313 	if (opt_skb)
1314 		goto ipv6_pktoptions;
1315 	return 0;
1316 
1317 reset:
1318 	tcp_v6_send_reset(sk, skb);
1319 discard:
1320 	if (opt_skb)
1321 		__kfree_skb(opt_skb);
1322 	kfree_skb(skb);
1323 	return 0;
1324 csum_err:
1325 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1326 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1327 	goto discard;
1328 
1329 
1330 ipv6_pktoptions:
1331 	/* Do you ask, what is it?
1332 
1333 	   1. skb was enqueued by tcp.
1334 	   2. skb is added to tail of read queue, rather than out of order.
1335 	   3. socket is not in passive state.
1336 	   4. Finally, it really contains options, which user wants to receive.
1337 	 */
1338 	tp = tcp_sk(sk);
1339 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1340 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1341 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1342 			np->mcast_oif = tcp_v6_iif(opt_skb);
1343 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1344 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1345 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1346 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1347 		if (np->repflow)
1348 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1349 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1350 			skb_set_owner_r(opt_skb, sk);
1351 			tcp_v6_restore_cb(opt_skb);
1352 			opt_skb = xchg(&np->pktoptions, opt_skb);
1353 		} else {
1354 			__kfree_skb(opt_skb);
1355 			opt_skb = xchg(&np->pktoptions, NULL);
1356 		}
1357 	}
1358 
1359 	kfree_skb(opt_skb);
1360 	return 0;
1361 }
1362 
1363 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1364 			   const struct tcphdr *th)
1365 {
1366 	/* This is tricky: we move IP6CB at its correct location into
1367 	 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1368 	 * _decode_session6() uses IP6CB().
1369 	 * barrier() makes sure compiler won't play aliasing games.
1370 	 */
1371 	memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1372 		sizeof(struct inet6_skb_parm));
1373 	barrier();
1374 
1375 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1376 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1377 				    skb->len - th->doff*4);
1378 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1379 	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1380 	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1381 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1382 	TCP_SKB_CB(skb)->sacked = 0;
1383 }
1384 
1385 static int tcp_v6_rcv(struct sk_buff *skb)
1386 {
1387 	const struct tcphdr *th;
1388 	const struct ipv6hdr *hdr;
1389 	bool refcounted;
1390 	struct sock *sk;
1391 	int ret;
1392 	struct net *net = dev_net(skb->dev);
1393 
1394 	if (skb->pkt_type != PACKET_HOST)
1395 		goto discard_it;
1396 
1397 	/*
1398 	 *	Count it even if it's bad.
1399 	 */
1400 	__TCP_INC_STATS(net, TCP_MIB_INSEGS);
1401 
1402 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1403 		goto discard_it;
1404 
1405 	th = (const struct tcphdr *)skb->data;
1406 
1407 	if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1408 		goto bad_packet;
1409 	if (!pskb_may_pull(skb, th->doff*4))
1410 		goto discard_it;
1411 
1412 	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1413 		goto csum_error;
1414 
1415 	th = (const struct tcphdr *)skb->data;
1416 	hdr = ipv6_hdr(skb);
1417 
1418 lookup:
1419 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1420 				th->source, th->dest, inet6_iif(skb),
1421 				&refcounted);
1422 	if (!sk)
1423 		goto no_tcp_socket;
1424 
1425 process:
1426 	if (sk->sk_state == TCP_TIME_WAIT)
1427 		goto do_time_wait;
1428 
1429 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
1430 		struct request_sock *req = inet_reqsk(sk);
1431 		struct sock *nsk;
1432 
1433 		sk = req->rsk_listener;
1434 		tcp_v6_fill_cb(skb, hdr, th);
1435 		if (tcp_v6_inbound_md5_hash(sk, skb)) {
1436 			sk_drops_add(sk, skb);
1437 			reqsk_put(req);
1438 			goto discard_it;
1439 		}
1440 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
1441 			inet_csk_reqsk_queue_drop_and_put(sk, req);
1442 			goto lookup;
1443 		}
1444 		sock_hold(sk);
1445 		refcounted = true;
1446 		nsk = tcp_check_req(sk, skb, req, false);
1447 		if (!nsk) {
1448 			reqsk_put(req);
1449 			goto discard_and_relse;
1450 		}
1451 		if (nsk == sk) {
1452 			reqsk_put(req);
1453 			tcp_v6_restore_cb(skb);
1454 		} else if (tcp_child_process(sk, nsk, skb)) {
1455 			tcp_v6_send_reset(nsk, skb);
1456 			goto discard_and_relse;
1457 		} else {
1458 			sock_put(sk);
1459 			return 0;
1460 		}
1461 	}
1462 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1463 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1464 		goto discard_and_relse;
1465 	}
1466 
1467 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1468 		goto discard_and_relse;
1469 
1470 	tcp_v6_fill_cb(skb, hdr, th);
1471 
1472 	if (tcp_v6_inbound_md5_hash(sk, skb))
1473 		goto discard_and_relse;
1474 
1475 	if (tcp_filter(sk, skb))
1476 		goto discard_and_relse;
1477 	th = (const struct tcphdr *)skb->data;
1478 	hdr = ipv6_hdr(skb);
1479 
1480 	skb->dev = NULL;
1481 
1482 	if (sk->sk_state == TCP_LISTEN) {
1483 		ret = tcp_v6_do_rcv(sk, skb);
1484 		goto put_and_return;
1485 	}
1486 
1487 	sk_incoming_cpu_update(sk);
1488 
1489 	bh_lock_sock_nested(sk);
1490 	tcp_segs_in(tcp_sk(sk), skb);
1491 	ret = 0;
1492 	if (!sock_owned_by_user(sk)) {
1493 		if (!tcp_prequeue(sk, skb))
1494 			ret = tcp_v6_do_rcv(sk, skb);
1495 	} else if (tcp_add_backlog(sk, skb)) {
1496 		goto discard_and_relse;
1497 	}
1498 	bh_unlock_sock(sk);
1499 
1500 put_and_return:
1501 	if (refcounted)
1502 		sock_put(sk);
1503 	return ret ? -1 : 0;
1504 
1505 no_tcp_socket:
1506 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1507 		goto discard_it;
1508 
1509 	tcp_v6_fill_cb(skb, hdr, th);
1510 
1511 	if (tcp_checksum_complete(skb)) {
1512 csum_error:
1513 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1514 bad_packet:
1515 		__TCP_INC_STATS(net, TCP_MIB_INERRS);
1516 	} else {
1517 		tcp_v6_send_reset(NULL, skb);
1518 	}
1519 
1520 discard_it:
1521 	kfree_skb(skb);
1522 	return 0;
1523 
1524 discard_and_relse:
1525 	sk_drops_add(sk, skb);
1526 	if (refcounted)
1527 		sock_put(sk);
1528 	goto discard_it;
1529 
1530 do_time_wait:
1531 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1532 		inet_twsk_put(inet_twsk(sk));
1533 		goto discard_it;
1534 	}
1535 
1536 	tcp_v6_fill_cb(skb, hdr, th);
1537 
1538 	if (tcp_checksum_complete(skb)) {
1539 		inet_twsk_put(inet_twsk(sk));
1540 		goto csum_error;
1541 	}
1542 
1543 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1544 	case TCP_TW_SYN:
1545 	{
1546 		struct sock *sk2;
1547 
1548 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1549 					    skb, __tcp_hdrlen(th),
1550 					    &ipv6_hdr(skb)->saddr, th->source,
1551 					    &ipv6_hdr(skb)->daddr,
1552 					    ntohs(th->dest), tcp_v6_iif(skb));
1553 		if (sk2) {
1554 			struct inet_timewait_sock *tw = inet_twsk(sk);
1555 			inet_twsk_deschedule_put(tw);
1556 			sk = sk2;
1557 			tcp_v6_restore_cb(skb);
1558 			refcounted = false;
1559 			goto process;
1560 		}
1561 		/* Fall through to ACK */
1562 	}
1563 	case TCP_TW_ACK:
1564 		tcp_v6_timewait_ack(sk, skb);
1565 		break;
1566 	case TCP_TW_RST:
1567 		tcp_v6_restore_cb(skb);
1568 		tcp_v6_send_reset(sk, skb);
1569 		inet_twsk_deschedule_put(inet_twsk(sk));
1570 		goto discard_it;
1571 	case TCP_TW_SUCCESS:
1572 		;
1573 	}
1574 	goto discard_it;
1575 }
1576 
1577 static void tcp_v6_early_demux(struct sk_buff *skb)
1578 {
1579 	const struct ipv6hdr *hdr;
1580 	const struct tcphdr *th;
1581 	struct sock *sk;
1582 
1583 	if (skb->pkt_type != PACKET_HOST)
1584 		return;
1585 
1586 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1587 		return;
1588 
1589 	hdr = ipv6_hdr(skb);
1590 	th = tcp_hdr(skb);
1591 
1592 	if (th->doff < sizeof(struct tcphdr) / 4)
1593 		return;
1594 
1595 	/* Note : We use inet6_iif() here, not tcp_v6_iif() */
1596 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1597 					&hdr->saddr, th->source,
1598 					&hdr->daddr, ntohs(th->dest),
1599 					inet6_iif(skb));
1600 	if (sk) {
1601 		skb->sk = sk;
1602 		skb->destructor = sock_edemux;
1603 		if (sk_fullsock(sk)) {
1604 			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1605 
1606 			if (dst)
1607 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1608 			if (dst &&
1609 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1610 				skb_dst_set_noref(skb, dst);
1611 		}
1612 	}
1613 }
1614 
1615 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1616 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1617 	.twsk_unique	= tcp_twsk_unique,
1618 	.twsk_destructor = tcp_twsk_destructor,
1619 };
1620 
1621 static const struct inet_connection_sock_af_ops ipv6_specific = {
1622 	.queue_xmit	   = inet6_csk_xmit,
1623 	.send_check	   = tcp_v6_send_check,
1624 	.rebuild_header	   = inet6_sk_rebuild_header,
1625 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1626 	.conn_request	   = tcp_v6_conn_request,
1627 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1628 	.net_header_len	   = sizeof(struct ipv6hdr),
1629 	.net_frag_header_len = sizeof(struct frag_hdr),
1630 	.setsockopt	   = ipv6_setsockopt,
1631 	.getsockopt	   = ipv6_getsockopt,
1632 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1633 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1634 #ifdef CONFIG_COMPAT
1635 	.compat_setsockopt = compat_ipv6_setsockopt,
1636 	.compat_getsockopt = compat_ipv6_getsockopt,
1637 #endif
1638 	.mtu_reduced	   = tcp_v6_mtu_reduced,
1639 };
1640 
1641 #ifdef CONFIG_TCP_MD5SIG
1642 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1643 	.md5_lookup	=	tcp_v6_md5_lookup,
1644 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1645 	.md5_parse	=	tcp_v6_parse_md5_keys,
1646 };
1647 #endif
1648 
1649 /*
1650  *	TCP over IPv4 via INET6 API
1651  */
1652 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1653 	.queue_xmit	   = ip_queue_xmit,
1654 	.send_check	   = tcp_v4_send_check,
1655 	.rebuild_header	   = inet_sk_rebuild_header,
1656 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1657 	.conn_request	   = tcp_v6_conn_request,
1658 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1659 	.net_header_len	   = sizeof(struct iphdr),
1660 	.setsockopt	   = ipv6_setsockopt,
1661 	.getsockopt	   = ipv6_getsockopt,
1662 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1663 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1664 #ifdef CONFIG_COMPAT
1665 	.compat_setsockopt = compat_ipv6_setsockopt,
1666 	.compat_getsockopt = compat_ipv6_getsockopt,
1667 #endif
1668 	.mtu_reduced	   = tcp_v4_mtu_reduced,
1669 };
1670 
1671 #ifdef CONFIG_TCP_MD5SIG
1672 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1673 	.md5_lookup	=	tcp_v4_md5_lookup,
1674 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1675 	.md5_parse	=	tcp_v6_parse_md5_keys,
1676 };
1677 #endif
1678 
1679 /* NOTE: A lot of things set to zero explicitly by call to
1680  *       sk_alloc() so need not be done here.
1681  */
1682 static int tcp_v6_init_sock(struct sock *sk)
1683 {
1684 	struct inet_connection_sock *icsk = inet_csk(sk);
1685 
1686 	tcp_init_sock(sk);
1687 
1688 	icsk->icsk_af_ops = &ipv6_specific;
1689 
1690 #ifdef CONFIG_TCP_MD5SIG
1691 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1692 #endif
1693 
1694 	return 0;
1695 }
1696 
1697 static void tcp_v6_destroy_sock(struct sock *sk)
1698 {
1699 	tcp_v4_destroy_sock(sk);
1700 	inet6_destroy_sock(sk);
1701 }
1702 
1703 #ifdef CONFIG_PROC_FS
1704 /* Proc filesystem TCPv6 sock list dumping. */
1705 static void get_openreq6(struct seq_file *seq,
1706 			 const struct request_sock *req, int i)
1707 {
1708 	long ttd = req->rsk_timer.expires - jiffies;
1709 	const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1710 	const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1711 
1712 	if (ttd < 0)
1713 		ttd = 0;
1714 
1715 	seq_printf(seq,
1716 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1717 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1718 		   i,
1719 		   src->s6_addr32[0], src->s6_addr32[1],
1720 		   src->s6_addr32[2], src->s6_addr32[3],
1721 		   inet_rsk(req)->ir_num,
1722 		   dest->s6_addr32[0], dest->s6_addr32[1],
1723 		   dest->s6_addr32[2], dest->s6_addr32[3],
1724 		   ntohs(inet_rsk(req)->ir_rmt_port),
1725 		   TCP_SYN_RECV,
1726 		   0, 0, /* could print option size, but that is af dependent. */
1727 		   1,   /* timers active (only the expire timer) */
1728 		   jiffies_to_clock_t(ttd),
1729 		   req->num_timeout,
1730 		   from_kuid_munged(seq_user_ns(seq),
1731 				    sock_i_uid(req->rsk_listener)),
1732 		   0,  /* non standard timer */
1733 		   0, /* open_requests have no inode */
1734 		   0, req);
1735 }
1736 
1737 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1738 {
1739 	const struct in6_addr *dest, *src;
1740 	__u16 destp, srcp;
1741 	int timer_active;
1742 	unsigned long timer_expires;
1743 	const struct inet_sock *inet = inet_sk(sp);
1744 	const struct tcp_sock *tp = tcp_sk(sp);
1745 	const struct inet_connection_sock *icsk = inet_csk(sp);
1746 	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1747 	int rx_queue;
1748 	int state;
1749 
1750 	dest  = &sp->sk_v6_daddr;
1751 	src   = &sp->sk_v6_rcv_saddr;
1752 	destp = ntohs(inet->inet_dport);
1753 	srcp  = ntohs(inet->inet_sport);
1754 
1755 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1756 	    icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
1757 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1758 		timer_active	= 1;
1759 		timer_expires	= icsk->icsk_timeout;
1760 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1761 		timer_active	= 4;
1762 		timer_expires	= icsk->icsk_timeout;
1763 	} else if (timer_pending(&sp->sk_timer)) {
1764 		timer_active	= 2;
1765 		timer_expires	= sp->sk_timer.expires;
1766 	} else {
1767 		timer_active	= 0;
1768 		timer_expires = jiffies;
1769 	}
1770 
1771 	state = sk_state_load(sp);
1772 	if (state == TCP_LISTEN)
1773 		rx_queue = sp->sk_ack_backlog;
1774 	else
1775 		/* Because we don't lock the socket,
1776 		 * we might find a transient negative value.
1777 		 */
1778 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1779 
1780 	seq_printf(seq,
1781 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1782 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1783 		   i,
1784 		   src->s6_addr32[0], src->s6_addr32[1],
1785 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1786 		   dest->s6_addr32[0], dest->s6_addr32[1],
1787 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1788 		   state,
1789 		   tp->write_seq - tp->snd_una,
1790 		   rx_queue,
1791 		   timer_active,
1792 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1793 		   icsk->icsk_retransmits,
1794 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1795 		   icsk->icsk_probes_out,
1796 		   sock_i_ino(sp),
1797 		   atomic_read(&sp->sk_refcnt), sp,
1798 		   jiffies_to_clock_t(icsk->icsk_rto),
1799 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1800 		   (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1801 		   tp->snd_cwnd,
1802 		   state == TCP_LISTEN ?
1803 			fastopenq->max_qlen :
1804 			(tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1805 		   );
1806 }
1807 
1808 static void get_timewait6_sock(struct seq_file *seq,
1809 			       struct inet_timewait_sock *tw, int i)
1810 {
1811 	long delta = tw->tw_timer.expires - jiffies;
1812 	const struct in6_addr *dest, *src;
1813 	__u16 destp, srcp;
1814 
1815 	dest = &tw->tw_v6_daddr;
1816 	src  = &tw->tw_v6_rcv_saddr;
1817 	destp = ntohs(tw->tw_dport);
1818 	srcp  = ntohs(tw->tw_sport);
1819 
1820 	seq_printf(seq,
1821 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1822 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1823 		   i,
1824 		   src->s6_addr32[0], src->s6_addr32[1],
1825 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1826 		   dest->s6_addr32[0], dest->s6_addr32[1],
1827 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1828 		   tw->tw_substate, 0, 0,
1829 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1830 		   atomic_read(&tw->tw_refcnt), tw);
1831 }
1832 
1833 static int tcp6_seq_show(struct seq_file *seq, void *v)
1834 {
1835 	struct tcp_iter_state *st;
1836 	struct sock *sk = v;
1837 
1838 	if (v == SEQ_START_TOKEN) {
1839 		seq_puts(seq,
1840 			 "  sl  "
1841 			 "local_address                         "
1842 			 "remote_address                        "
1843 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1844 			 "   uid  timeout inode\n");
1845 		goto out;
1846 	}
1847 	st = seq->private;
1848 
1849 	if (sk->sk_state == TCP_TIME_WAIT)
1850 		get_timewait6_sock(seq, v, st->num);
1851 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
1852 		get_openreq6(seq, v, st->num);
1853 	else
1854 		get_tcp6_sock(seq, v, st->num);
1855 out:
1856 	return 0;
1857 }
1858 
1859 static const struct file_operations tcp6_afinfo_seq_fops = {
1860 	.owner   = THIS_MODULE,
1861 	.open    = tcp_seq_open,
1862 	.read    = seq_read,
1863 	.llseek  = seq_lseek,
1864 	.release = seq_release_net
1865 };
1866 
1867 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1868 	.name		= "tcp6",
1869 	.family		= AF_INET6,
1870 	.seq_fops	= &tcp6_afinfo_seq_fops,
1871 	.seq_ops	= {
1872 		.show		= tcp6_seq_show,
1873 	},
1874 };
1875 
1876 int __net_init tcp6_proc_init(struct net *net)
1877 {
1878 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1879 }
1880 
1881 void tcp6_proc_exit(struct net *net)
1882 {
1883 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1884 }
1885 #endif
1886 
1887 struct proto tcpv6_prot = {
1888 	.name			= "TCPv6",
1889 	.owner			= THIS_MODULE,
1890 	.close			= tcp_close,
1891 	.connect		= tcp_v6_connect,
1892 	.disconnect		= tcp_disconnect,
1893 	.accept			= inet_csk_accept,
1894 	.ioctl			= tcp_ioctl,
1895 	.init			= tcp_v6_init_sock,
1896 	.destroy		= tcp_v6_destroy_sock,
1897 	.shutdown		= tcp_shutdown,
1898 	.setsockopt		= tcp_setsockopt,
1899 	.getsockopt		= tcp_getsockopt,
1900 	.keepalive		= tcp_set_keepalive,
1901 	.recvmsg		= tcp_recvmsg,
1902 	.sendmsg		= tcp_sendmsg,
1903 	.sendpage		= tcp_sendpage,
1904 	.backlog_rcv		= tcp_v6_do_rcv,
1905 	.release_cb		= tcp_release_cb,
1906 	.hash			= inet6_hash,
1907 	.unhash			= inet_unhash,
1908 	.get_port		= inet_csk_get_port,
1909 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1910 	.stream_memory_free	= tcp_stream_memory_free,
1911 	.sockets_allocated	= &tcp_sockets_allocated,
1912 	.memory_allocated	= &tcp_memory_allocated,
1913 	.memory_pressure	= &tcp_memory_pressure,
1914 	.orphan_count		= &tcp_orphan_count,
1915 	.sysctl_mem		= sysctl_tcp_mem,
1916 	.sysctl_wmem		= sysctl_tcp_wmem,
1917 	.sysctl_rmem		= sysctl_tcp_rmem,
1918 	.max_header		= MAX_TCP_HEADER,
1919 	.obj_size		= sizeof(struct tcp6_sock),
1920 	.slab_flags		= SLAB_TYPESAFE_BY_RCU,
1921 	.twsk_prot		= &tcp6_timewait_sock_ops,
1922 	.rsk_prot		= &tcp6_request_sock_ops,
1923 	.h.hashinfo		= &tcp_hashinfo,
1924 	.no_autobind		= true,
1925 #ifdef CONFIG_COMPAT
1926 	.compat_setsockopt	= compat_tcp_setsockopt,
1927 	.compat_getsockopt	= compat_tcp_getsockopt,
1928 #endif
1929 	.diag_destroy		= tcp_abort,
1930 };
1931 
1932 static struct inet6_protocol tcpv6_protocol = {
1933 	.early_demux	=	tcp_v6_early_demux,
1934 	.early_demux_handler =  tcp_v6_early_demux,
1935 	.handler	=	tcp_v6_rcv,
1936 	.err_handler	=	tcp_v6_err,
1937 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1938 };
1939 
1940 static struct inet_protosw tcpv6_protosw = {
1941 	.type		=	SOCK_STREAM,
1942 	.protocol	=	IPPROTO_TCP,
1943 	.prot		=	&tcpv6_prot,
1944 	.ops		=	&inet6_stream_ops,
1945 	.flags		=	INET_PROTOSW_PERMANENT |
1946 				INET_PROTOSW_ICSK,
1947 };
1948 
1949 static int __net_init tcpv6_net_init(struct net *net)
1950 {
1951 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1952 				    SOCK_RAW, IPPROTO_TCP, net);
1953 }
1954 
1955 static void __net_exit tcpv6_net_exit(struct net *net)
1956 {
1957 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1958 }
1959 
1960 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1961 {
1962 	inet_twsk_purge(&tcp_hashinfo, AF_INET6);
1963 }
1964 
1965 static struct pernet_operations tcpv6_net_ops = {
1966 	.init	    = tcpv6_net_init,
1967 	.exit	    = tcpv6_net_exit,
1968 	.exit_batch = tcpv6_net_exit_batch,
1969 };
1970 
1971 int __init tcpv6_init(void)
1972 {
1973 	int ret;
1974 
1975 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1976 	if (ret)
1977 		goto out;
1978 
1979 	/* register inet6 protocol */
1980 	ret = inet6_register_protosw(&tcpv6_protosw);
1981 	if (ret)
1982 		goto out_tcpv6_protocol;
1983 
1984 	ret = register_pernet_subsys(&tcpv6_net_ops);
1985 	if (ret)
1986 		goto out_tcpv6_protosw;
1987 out:
1988 	return ret;
1989 
1990 out_tcpv6_protosw:
1991 	inet6_unregister_protosw(&tcpv6_protosw);
1992 out_tcpv6_protocol:
1993 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1994 	goto out;
1995 }
1996 
1997 void tcpv6_exit(void)
1998 {
1999 	unregister_pernet_subsys(&tcpv6_net_ops);
2000 	inet6_unregister_protosw(&tcpv6_protosw);
2001 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2002 }
2003