xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision 9ee0034b8f49aaaa7e7c2da8db1038915db99c19)
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_sequence(const struct sk_buff *skb)
105 {
106 	return secure_tcpv6_sequence_number(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 int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
113 			  int addr_len)
114 {
115 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
116 	struct inet_sock *inet = inet_sk(sk);
117 	struct inet_connection_sock *icsk = inet_csk(sk);
118 	struct ipv6_pinfo *np = inet6_sk(sk);
119 	struct tcp_sock *tp = tcp_sk(sk);
120 	struct in6_addr *saddr = NULL, *final_p, final;
121 	struct ipv6_txoptions *opt;
122 	struct flowi6 fl6;
123 	struct dst_entry *dst;
124 	int addr_type;
125 	int err;
126 
127 	if (addr_len < SIN6_LEN_RFC2133)
128 		return -EINVAL;
129 
130 	if (usin->sin6_family != AF_INET6)
131 		return -EAFNOSUPPORT;
132 
133 	memset(&fl6, 0, sizeof(fl6));
134 
135 	if (np->sndflow) {
136 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
137 		IP6_ECN_flow_init(fl6.flowlabel);
138 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
139 			struct ip6_flowlabel *flowlabel;
140 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
141 			if (!flowlabel)
142 				return -EINVAL;
143 			fl6_sock_release(flowlabel);
144 		}
145 	}
146 
147 	/*
148 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
149 	 */
150 
151 	if (ipv6_addr_any(&usin->sin6_addr))
152 		usin->sin6_addr.s6_addr[15] = 0x1;
153 
154 	addr_type = ipv6_addr_type(&usin->sin6_addr);
155 
156 	if (addr_type & IPV6_ADDR_MULTICAST)
157 		return -ENETUNREACH;
158 
159 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
160 		if (addr_len >= sizeof(struct sockaddr_in6) &&
161 		    usin->sin6_scope_id) {
162 			/* If interface is set while binding, indices
163 			 * must coincide.
164 			 */
165 			if (sk->sk_bound_dev_if &&
166 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
167 				return -EINVAL;
168 
169 			sk->sk_bound_dev_if = usin->sin6_scope_id;
170 		}
171 
172 		/* Connect to link-local address requires an interface */
173 		if (!sk->sk_bound_dev_if)
174 			return -EINVAL;
175 	}
176 
177 	if (tp->rx_opt.ts_recent_stamp &&
178 	    !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
179 		tp->rx_opt.ts_recent = 0;
180 		tp->rx_opt.ts_recent_stamp = 0;
181 		tp->write_seq = 0;
182 	}
183 
184 	sk->sk_v6_daddr = usin->sin6_addr;
185 	np->flow_label = fl6.flowlabel;
186 
187 	/*
188 	 *	TCP over IPv4
189 	 */
190 
191 	if (addr_type == IPV6_ADDR_MAPPED) {
192 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
193 		struct sockaddr_in sin;
194 
195 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
196 
197 		if (__ipv6_only_sock(sk))
198 			return -ENETUNREACH;
199 
200 		sin.sin_family = AF_INET;
201 		sin.sin_port = usin->sin6_port;
202 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
203 
204 		icsk->icsk_af_ops = &ipv6_mapped;
205 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
206 #ifdef CONFIG_TCP_MD5SIG
207 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
208 #endif
209 
210 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
211 
212 		if (err) {
213 			icsk->icsk_ext_hdr_len = exthdrlen;
214 			icsk->icsk_af_ops = &ipv6_specific;
215 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
216 #ifdef CONFIG_TCP_MD5SIG
217 			tp->af_specific = &tcp_sock_ipv6_specific;
218 #endif
219 			goto failure;
220 		}
221 		np->saddr = sk->sk_v6_rcv_saddr;
222 
223 		return err;
224 	}
225 
226 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
227 		saddr = &sk->sk_v6_rcv_saddr;
228 
229 	fl6.flowi6_proto = IPPROTO_TCP;
230 	fl6.daddr = sk->sk_v6_daddr;
231 	fl6.saddr = saddr ? *saddr : np->saddr;
232 	fl6.flowi6_oif = sk->sk_bound_dev_if;
233 	fl6.flowi6_mark = sk->sk_mark;
234 	fl6.fl6_dport = usin->sin6_port;
235 	fl6.fl6_sport = inet->inet_sport;
236 
237 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
238 	final_p = fl6_update_dst(&fl6, opt, &final);
239 
240 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
241 
242 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
243 	if (IS_ERR(dst)) {
244 		err = PTR_ERR(dst);
245 		goto failure;
246 	}
247 
248 	if (!saddr) {
249 		saddr = &fl6.saddr;
250 		sk->sk_v6_rcv_saddr = *saddr;
251 	}
252 
253 	/* set the source address */
254 	np->saddr = *saddr;
255 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
256 
257 	sk->sk_gso_type = SKB_GSO_TCPV6;
258 	ip6_dst_store(sk, dst, NULL, NULL);
259 
260 	if (tcp_death_row.sysctl_tw_recycle &&
261 	    !tp->rx_opt.ts_recent_stamp &&
262 	    ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
263 		tcp_fetch_timewait_stamp(sk, dst);
264 
265 	icsk->icsk_ext_hdr_len = 0;
266 	if (opt)
267 		icsk->icsk_ext_hdr_len = opt->opt_flen +
268 					 opt->opt_nflen;
269 
270 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
271 
272 	inet->inet_dport = usin->sin6_port;
273 
274 	tcp_set_state(sk, TCP_SYN_SENT);
275 	err = inet6_hash_connect(&tcp_death_row, sk);
276 	if (err)
277 		goto late_failure;
278 
279 	sk_set_txhash(sk);
280 
281 	if (!tp->write_seq && likely(!tp->repair))
282 		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
283 							     sk->sk_v6_daddr.s6_addr32,
284 							     inet->inet_sport,
285 							     inet->inet_dport);
286 
287 	err = tcp_connect(sk);
288 	if (err)
289 		goto late_failure;
290 
291 	return 0;
292 
293 late_failure:
294 	tcp_set_state(sk, TCP_CLOSE);
295 	__sk_dst_reset(sk);
296 failure:
297 	inet->inet_dport = 0;
298 	sk->sk_route_caps = 0;
299 	return err;
300 }
301 
302 static void tcp_v6_mtu_reduced(struct sock *sk)
303 {
304 	struct dst_entry *dst;
305 
306 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
307 		return;
308 
309 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
310 	if (!dst)
311 		return;
312 
313 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
314 		tcp_sync_mss(sk, dst_mtu(dst));
315 		tcp_simple_retransmit(sk);
316 	}
317 }
318 
319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
320 		u8 type, u8 code, int offset, __be32 info)
321 {
322 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
323 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
324 	struct net *net = dev_net(skb->dev);
325 	struct request_sock *fastopen;
326 	struct ipv6_pinfo *np;
327 	struct tcp_sock *tp;
328 	__u32 seq, snd_una;
329 	struct sock *sk;
330 	bool fatal;
331 	int err;
332 
333 	sk = __inet6_lookup_established(net, &tcp_hashinfo,
334 					&hdr->daddr, th->dest,
335 					&hdr->saddr, ntohs(th->source),
336 					skb->dev->ifindex);
337 
338 	if (!sk) {
339 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
340 				  ICMP6_MIB_INERRORS);
341 		return;
342 	}
343 
344 	if (sk->sk_state == TCP_TIME_WAIT) {
345 		inet_twsk_put(inet_twsk(sk));
346 		return;
347 	}
348 	seq = ntohl(th->seq);
349 	fatal = icmpv6_err_convert(type, code, &err);
350 	if (sk->sk_state == TCP_NEW_SYN_RECV)
351 		return tcp_req_err(sk, seq, fatal);
352 
353 	bh_lock_sock(sk);
354 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
355 		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
356 
357 	if (sk->sk_state == TCP_CLOSE)
358 		goto out;
359 
360 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
361 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
362 		goto out;
363 	}
364 
365 	tp = tcp_sk(sk);
366 	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
367 	fastopen = tp->fastopen_rsk;
368 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
369 	if (sk->sk_state != TCP_LISTEN &&
370 	    !between(seq, snd_una, tp->snd_nxt)) {
371 		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
372 		goto out;
373 	}
374 
375 	np = inet6_sk(sk);
376 
377 	if (type == NDISC_REDIRECT) {
378 		struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
379 
380 		if (dst)
381 			dst->ops->redirect(dst, sk, skb);
382 		goto out;
383 	}
384 
385 	if (type == ICMPV6_PKT_TOOBIG) {
386 		/* We are not interested in TCP_LISTEN and open_requests
387 		 * (SYN-ACKs send out by Linux are always <576bytes so
388 		 * they should go through unfragmented).
389 		 */
390 		if (sk->sk_state == TCP_LISTEN)
391 			goto out;
392 
393 		if (!ip6_sk_accept_pmtu(sk))
394 			goto out;
395 
396 		tp->mtu_info = ntohl(info);
397 		if (!sock_owned_by_user(sk))
398 			tcp_v6_mtu_reduced(sk);
399 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
400 					   &tp->tsq_flags))
401 			sock_hold(sk);
402 		goto out;
403 	}
404 
405 
406 	/* Might be for an request_sock */
407 	switch (sk->sk_state) {
408 	case TCP_SYN_SENT:
409 	case TCP_SYN_RECV:
410 		/* Only in fast or simultaneous open. If a fast open socket is
411 		 * is already accepted it is treated as a connected one below.
412 		 */
413 		if (fastopen && !fastopen->sk)
414 			break;
415 
416 		if (!sock_owned_by_user(sk)) {
417 			sk->sk_err = err;
418 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
419 
420 			tcp_done(sk);
421 		} else
422 			sk->sk_err_soft = err;
423 		goto out;
424 	}
425 
426 	if (!sock_owned_by_user(sk) && np->recverr) {
427 		sk->sk_err = err;
428 		sk->sk_error_report(sk);
429 	} else
430 		sk->sk_err_soft = err;
431 
432 out:
433 	bh_unlock_sock(sk);
434 	sock_put(sk);
435 }
436 
437 
438 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
439 			      struct flowi *fl,
440 			      struct request_sock *req,
441 			      struct tcp_fastopen_cookie *foc,
442 			      enum tcp_synack_type synack_type)
443 {
444 	struct inet_request_sock *ireq = inet_rsk(req);
445 	struct ipv6_pinfo *np = inet6_sk(sk);
446 	struct ipv6_txoptions *opt;
447 	struct flowi6 *fl6 = &fl->u.ip6;
448 	struct sk_buff *skb;
449 	int err = -ENOMEM;
450 
451 	/* First, grab a route. */
452 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
453 					       IPPROTO_TCP)) == NULL)
454 		goto done;
455 
456 	skb = tcp_make_synack(sk, dst, req, foc, synack_type);
457 
458 	if (skb) {
459 		__tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
460 				    &ireq->ir_v6_rmt_addr);
461 
462 		fl6->daddr = ireq->ir_v6_rmt_addr;
463 		if (np->repflow && ireq->pktopts)
464 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
465 
466 		rcu_read_lock();
467 		opt = ireq->ipv6_opt;
468 		if (!opt)
469 			opt = rcu_dereference(np->opt);
470 		err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
471 		rcu_read_unlock();
472 		err = net_xmit_eval(err);
473 	}
474 
475 done:
476 	return err;
477 }
478 
479 
480 static void tcp_v6_reqsk_destructor(struct request_sock *req)
481 {
482 	kfree(inet_rsk(req)->ipv6_opt);
483 	kfree_skb(inet_rsk(req)->pktopts);
484 }
485 
486 #ifdef CONFIG_TCP_MD5SIG
487 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
488 						   const struct in6_addr *addr)
489 {
490 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
491 }
492 
493 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
494 						const struct sock *addr_sk)
495 {
496 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
497 }
498 
499 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
500 				 int optlen)
501 {
502 	struct tcp_md5sig cmd;
503 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
504 
505 	if (optlen < sizeof(cmd))
506 		return -EINVAL;
507 
508 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
509 		return -EFAULT;
510 
511 	if (sin6->sin6_family != AF_INET6)
512 		return -EINVAL;
513 
514 	if (!cmd.tcpm_keylen) {
515 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
516 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
517 					      AF_INET);
518 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
519 				      AF_INET6);
520 	}
521 
522 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
523 		return -EINVAL;
524 
525 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
526 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
527 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
528 
529 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
530 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
531 }
532 
533 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
534 				   const struct in6_addr *daddr,
535 				   const struct in6_addr *saddr,
536 				   const struct tcphdr *th, int nbytes)
537 {
538 	struct tcp6_pseudohdr *bp;
539 	struct scatterlist sg;
540 	struct tcphdr *_th;
541 
542 	bp = hp->scratch;
543 	/* 1. TCP pseudo-header (RFC2460) */
544 	bp->saddr = *saddr;
545 	bp->daddr = *daddr;
546 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
547 	bp->len = cpu_to_be32(nbytes);
548 
549 	_th = (struct tcphdr *)(bp + 1);
550 	memcpy(_th, th, sizeof(*th));
551 	_th->check = 0;
552 
553 	sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
554 	ahash_request_set_crypt(hp->md5_req, &sg, NULL,
555 				sizeof(*bp) + sizeof(*th));
556 	return crypto_ahash_update(hp->md5_req);
557 }
558 
559 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
560 			       const struct in6_addr *daddr, struct in6_addr *saddr,
561 			       const struct tcphdr *th)
562 {
563 	struct tcp_md5sig_pool *hp;
564 	struct ahash_request *req;
565 
566 	hp = tcp_get_md5sig_pool();
567 	if (!hp)
568 		goto clear_hash_noput;
569 	req = hp->md5_req;
570 
571 	if (crypto_ahash_init(req))
572 		goto clear_hash;
573 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
574 		goto clear_hash;
575 	if (tcp_md5_hash_key(hp, key))
576 		goto clear_hash;
577 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
578 	if (crypto_ahash_final(req))
579 		goto clear_hash;
580 
581 	tcp_put_md5sig_pool();
582 	return 0;
583 
584 clear_hash:
585 	tcp_put_md5sig_pool();
586 clear_hash_noput:
587 	memset(md5_hash, 0, 16);
588 	return 1;
589 }
590 
591 static int tcp_v6_md5_hash_skb(char *md5_hash,
592 			       const struct tcp_md5sig_key *key,
593 			       const struct sock *sk,
594 			       const struct sk_buff *skb)
595 {
596 	const struct in6_addr *saddr, *daddr;
597 	struct tcp_md5sig_pool *hp;
598 	struct ahash_request *req;
599 	const struct tcphdr *th = tcp_hdr(skb);
600 
601 	if (sk) { /* valid for establish/request sockets */
602 		saddr = &sk->sk_v6_rcv_saddr;
603 		daddr = &sk->sk_v6_daddr;
604 	} else {
605 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
606 		saddr = &ip6h->saddr;
607 		daddr = &ip6h->daddr;
608 	}
609 
610 	hp = tcp_get_md5sig_pool();
611 	if (!hp)
612 		goto clear_hash_noput;
613 	req = hp->md5_req;
614 
615 	if (crypto_ahash_init(req))
616 		goto clear_hash;
617 
618 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
619 		goto clear_hash;
620 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
621 		goto clear_hash;
622 	if (tcp_md5_hash_key(hp, key))
623 		goto clear_hash;
624 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
625 	if (crypto_ahash_final(req))
626 		goto clear_hash;
627 
628 	tcp_put_md5sig_pool();
629 	return 0;
630 
631 clear_hash:
632 	tcp_put_md5sig_pool();
633 clear_hash_noput:
634 	memset(md5_hash, 0, 16);
635 	return 1;
636 }
637 
638 #endif
639 
640 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
641 				    const struct sk_buff *skb)
642 {
643 #ifdef CONFIG_TCP_MD5SIG
644 	const __u8 *hash_location = NULL;
645 	struct tcp_md5sig_key *hash_expected;
646 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
647 	const struct tcphdr *th = tcp_hdr(skb);
648 	int genhash;
649 	u8 newhash[16];
650 
651 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
652 	hash_location = tcp_parse_md5sig_option(th);
653 
654 	/* We've parsed the options - do we have a hash? */
655 	if (!hash_expected && !hash_location)
656 		return false;
657 
658 	if (hash_expected && !hash_location) {
659 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
660 		return true;
661 	}
662 
663 	if (!hash_expected && hash_location) {
664 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
665 		return true;
666 	}
667 
668 	/* check the signature */
669 	genhash = tcp_v6_md5_hash_skb(newhash,
670 				      hash_expected,
671 				      NULL, skb);
672 
673 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
674 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
675 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
676 				     genhash ? "failed" : "mismatch",
677 				     &ip6h->saddr, ntohs(th->source),
678 				     &ip6h->daddr, ntohs(th->dest));
679 		return true;
680 	}
681 #endif
682 	return false;
683 }
684 
685 static void tcp_v6_init_req(struct request_sock *req,
686 			    const struct sock *sk_listener,
687 			    struct sk_buff *skb)
688 {
689 	struct inet_request_sock *ireq = inet_rsk(req);
690 	const struct ipv6_pinfo *np = inet6_sk(sk_listener);
691 
692 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
693 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
694 
695 	/* So that link locals have meaning */
696 	if (!sk_listener->sk_bound_dev_if &&
697 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
698 		ireq->ir_iif = tcp_v6_iif(skb);
699 
700 	if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
701 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
702 	     np->rxopt.bits.rxinfo ||
703 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
704 	     np->rxopt.bits.rxohlim || np->repflow)) {
705 		atomic_inc(&skb->users);
706 		ireq->pktopts = skb;
707 	}
708 }
709 
710 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
711 					  struct flowi *fl,
712 					  const struct request_sock *req,
713 					  bool *strict)
714 {
715 	if (strict)
716 		*strict = true;
717 	return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
718 }
719 
720 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
721 	.family		=	AF_INET6,
722 	.obj_size	=	sizeof(struct tcp6_request_sock),
723 	.rtx_syn_ack	=	tcp_rtx_synack,
724 	.send_ack	=	tcp_v6_reqsk_send_ack,
725 	.destructor	=	tcp_v6_reqsk_destructor,
726 	.send_reset	=	tcp_v6_send_reset,
727 	.syn_ack_timeout =	tcp_syn_ack_timeout,
728 };
729 
730 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
731 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
732 				sizeof(struct ipv6hdr),
733 #ifdef CONFIG_TCP_MD5SIG
734 	.req_md5_lookup	=	tcp_v6_md5_lookup,
735 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
736 #endif
737 	.init_req	=	tcp_v6_init_req,
738 #ifdef CONFIG_SYN_COOKIES
739 	.cookie_init_seq =	cookie_v6_init_sequence,
740 #endif
741 	.route_req	=	tcp_v6_route_req,
742 	.init_seq	=	tcp_v6_init_sequence,
743 	.send_synack	=	tcp_v6_send_synack,
744 };
745 
746 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
747 				 u32 ack, u32 win, u32 tsval, u32 tsecr,
748 				 int oif, struct tcp_md5sig_key *key, int rst,
749 				 u8 tclass, __be32 label)
750 {
751 	const struct tcphdr *th = tcp_hdr(skb);
752 	struct tcphdr *t1;
753 	struct sk_buff *buff;
754 	struct flowi6 fl6;
755 	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
756 	struct sock *ctl_sk = net->ipv6.tcp_sk;
757 	unsigned int tot_len = sizeof(struct tcphdr);
758 	struct dst_entry *dst;
759 	__be32 *topt;
760 
761 	if (tsecr)
762 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
763 #ifdef CONFIG_TCP_MD5SIG
764 	if (key)
765 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
766 #endif
767 
768 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
769 			 GFP_ATOMIC);
770 	if (!buff)
771 		return;
772 
773 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
774 
775 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
776 	skb_reset_transport_header(buff);
777 
778 	/* Swap the send and the receive. */
779 	memset(t1, 0, sizeof(*t1));
780 	t1->dest = th->source;
781 	t1->source = th->dest;
782 	t1->doff = tot_len / 4;
783 	t1->seq = htonl(seq);
784 	t1->ack_seq = htonl(ack);
785 	t1->ack = !rst || !th->ack;
786 	t1->rst = rst;
787 	t1->window = htons(win);
788 
789 	topt = (__be32 *)(t1 + 1);
790 
791 	if (tsecr) {
792 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
793 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
794 		*topt++ = htonl(tsval);
795 		*topt++ = htonl(tsecr);
796 	}
797 
798 #ifdef CONFIG_TCP_MD5SIG
799 	if (key) {
800 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
801 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
802 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
803 				    &ipv6_hdr(skb)->saddr,
804 				    &ipv6_hdr(skb)->daddr, t1);
805 	}
806 #endif
807 
808 	memset(&fl6, 0, sizeof(fl6));
809 	fl6.daddr = ipv6_hdr(skb)->saddr;
810 	fl6.saddr = ipv6_hdr(skb)->daddr;
811 	fl6.flowlabel = label;
812 
813 	buff->ip_summed = CHECKSUM_PARTIAL;
814 	buff->csum = 0;
815 
816 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
817 
818 	fl6.flowi6_proto = IPPROTO_TCP;
819 	if (rt6_need_strict(&fl6.daddr) && !oif)
820 		fl6.flowi6_oif = tcp_v6_iif(skb);
821 	else {
822 		if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
823 			oif = skb->skb_iif;
824 
825 		fl6.flowi6_oif = oif;
826 	}
827 
828 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
829 	fl6.fl6_dport = t1->dest;
830 	fl6.fl6_sport = t1->source;
831 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
832 
833 	/* Pass a socket to ip6_dst_lookup either it is for RST
834 	 * Underlying function will use this to retrieve the network
835 	 * namespace
836 	 */
837 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
838 	if (!IS_ERR(dst)) {
839 		skb_dst_set(buff, dst);
840 		ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
841 		TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
842 		if (rst)
843 			TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
844 		return;
845 	}
846 
847 	kfree_skb(buff);
848 }
849 
850 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
851 {
852 	const struct tcphdr *th = tcp_hdr(skb);
853 	u32 seq = 0, ack_seq = 0;
854 	struct tcp_md5sig_key *key = NULL;
855 #ifdef CONFIG_TCP_MD5SIG
856 	const __u8 *hash_location = NULL;
857 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
858 	unsigned char newhash[16];
859 	int genhash;
860 	struct sock *sk1 = NULL;
861 #endif
862 	int oif;
863 
864 	if (th->rst)
865 		return;
866 
867 	/* If sk not NULL, it means we did a successful lookup and incoming
868 	 * route had to be correct. prequeue might have dropped our dst.
869 	 */
870 	if (!sk && !ipv6_unicast_destination(skb))
871 		return;
872 
873 #ifdef CONFIG_TCP_MD5SIG
874 	rcu_read_lock();
875 	hash_location = tcp_parse_md5sig_option(th);
876 	if (sk && sk_fullsock(sk)) {
877 		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
878 	} else if (hash_location) {
879 		/*
880 		 * active side is lost. Try to find listening socket through
881 		 * source port, and then find md5 key through listening socket.
882 		 * we are not loose security here:
883 		 * Incoming packet is checked with md5 hash with finding key,
884 		 * no RST generated if md5 hash doesn't match.
885 		 */
886 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
887 					   &tcp_hashinfo, NULL, 0,
888 					   &ipv6h->saddr,
889 					   th->source, &ipv6h->daddr,
890 					   ntohs(th->source), tcp_v6_iif(skb));
891 		if (!sk1)
892 			goto out;
893 
894 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
895 		if (!key)
896 			goto out;
897 
898 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
899 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
900 			goto out;
901 	}
902 #endif
903 
904 	if (th->ack)
905 		seq = ntohl(th->ack_seq);
906 	else
907 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
908 			  (th->doff << 2);
909 
910 	oif = sk ? sk->sk_bound_dev_if : 0;
911 	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
912 
913 #ifdef CONFIG_TCP_MD5SIG
914 out:
915 	rcu_read_unlock();
916 #endif
917 }
918 
919 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
920 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
921 			    struct tcp_md5sig_key *key, u8 tclass,
922 			    __be32 label)
923 {
924 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
925 			     tclass, label);
926 }
927 
928 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
929 {
930 	struct inet_timewait_sock *tw = inet_twsk(sk);
931 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
932 
933 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
934 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
935 			tcp_time_stamp + tcptw->tw_ts_offset,
936 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
937 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
938 
939 	inet_twsk_put(tw);
940 }
941 
942 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
943 				  struct request_sock *req)
944 {
945 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
946 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
947 	 */
948 	/* RFC 7323 2.3
949 	 * The window field (SEG.WND) of every outgoing segment, with the
950 	 * exception of <SYN> segments, MUST be right-shifted by
951 	 * Rcv.Wind.Shift bits:
952 	 */
953 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
954 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
955 			tcp_rsk(req)->rcv_nxt,
956 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
957 			tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
958 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
959 			0, 0);
960 }
961 
962 
963 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
964 {
965 #ifdef CONFIG_SYN_COOKIES
966 	const struct tcphdr *th = tcp_hdr(skb);
967 
968 	if (!th->syn)
969 		sk = cookie_v6_check(sk, skb);
970 #endif
971 	return sk;
972 }
973 
974 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
975 {
976 	if (skb->protocol == htons(ETH_P_IP))
977 		return tcp_v4_conn_request(sk, skb);
978 
979 	if (!ipv6_unicast_destination(skb))
980 		goto drop;
981 
982 	return tcp_conn_request(&tcp6_request_sock_ops,
983 				&tcp_request_sock_ipv6_ops, sk, skb);
984 
985 drop:
986 	tcp_listendrop(sk);
987 	return 0; /* don't send reset */
988 }
989 
990 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
991 					 struct request_sock *req,
992 					 struct dst_entry *dst,
993 					 struct request_sock *req_unhash,
994 					 bool *own_req)
995 {
996 	struct inet_request_sock *ireq;
997 	struct ipv6_pinfo *newnp;
998 	const struct ipv6_pinfo *np = inet6_sk(sk);
999 	struct ipv6_txoptions *opt;
1000 	struct tcp6_sock *newtcp6sk;
1001 	struct inet_sock *newinet;
1002 	struct tcp_sock *newtp;
1003 	struct sock *newsk;
1004 #ifdef CONFIG_TCP_MD5SIG
1005 	struct tcp_md5sig_key *key;
1006 #endif
1007 	struct flowi6 fl6;
1008 
1009 	if (skb->protocol == htons(ETH_P_IP)) {
1010 		/*
1011 		 *	v6 mapped
1012 		 */
1013 
1014 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1015 					     req_unhash, own_req);
1016 
1017 		if (!newsk)
1018 			return NULL;
1019 
1020 		newtcp6sk = (struct tcp6_sock *)newsk;
1021 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1022 
1023 		newinet = inet_sk(newsk);
1024 		newnp = inet6_sk(newsk);
1025 		newtp = tcp_sk(newsk);
1026 
1027 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1028 
1029 		newnp->saddr = newsk->sk_v6_rcv_saddr;
1030 
1031 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1032 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1033 #ifdef CONFIG_TCP_MD5SIG
1034 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1035 #endif
1036 
1037 		newnp->ipv6_ac_list = NULL;
1038 		newnp->ipv6_fl_list = NULL;
1039 		newnp->pktoptions  = NULL;
1040 		newnp->opt	   = NULL;
1041 		newnp->mcast_oif   = tcp_v6_iif(skb);
1042 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1043 		newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1044 		if (np->repflow)
1045 			newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1046 
1047 		/*
1048 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1049 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1050 		 * that function for the gory details. -acme
1051 		 */
1052 
1053 		/* It is tricky place. Until this moment IPv4 tcp
1054 		   worked with IPv6 icsk.icsk_af_ops.
1055 		   Sync it now.
1056 		 */
1057 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1058 
1059 		return newsk;
1060 	}
1061 
1062 	ireq = inet_rsk(req);
1063 
1064 	if (sk_acceptq_is_full(sk))
1065 		goto out_overflow;
1066 
1067 	if (!dst) {
1068 		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1069 		if (!dst)
1070 			goto out;
1071 	}
1072 
1073 	newsk = tcp_create_openreq_child(sk, req, skb);
1074 	if (!newsk)
1075 		goto out_nonewsk;
1076 
1077 	/*
1078 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1079 	 * count here, tcp_create_openreq_child now does this for us, see the
1080 	 * comment in that function for the gory details. -acme
1081 	 */
1082 
1083 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1084 	ip6_dst_store(newsk, dst, NULL, NULL);
1085 	inet6_sk_rx_dst_set(newsk, skb);
1086 
1087 	newtcp6sk = (struct tcp6_sock *)newsk;
1088 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1089 
1090 	newtp = tcp_sk(newsk);
1091 	newinet = inet_sk(newsk);
1092 	newnp = inet6_sk(newsk);
1093 
1094 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1095 
1096 	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1097 	newnp->saddr = ireq->ir_v6_loc_addr;
1098 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1099 	newsk->sk_bound_dev_if = ireq->ir_iif;
1100 
1101 	/* Now IPv6 options...
1102 
1103 	   First: no IPv4 options.
1104 	 */
1105 	newinet->inet_opt = NULL;
1106 	newnp->ipv6_ac_list = NULL;
1107 	newnp->ipv6_fl_list = NULL;
1108 
1109 	/* Clone RX bits */
1110 	newnp->rxopt.all = np->rxopt.all;
1111 
1112 	newnp->pktoptions = NULL;
1113 	newnp->opt	  = NULL;
1114 	newnp->mcast_oif  = tcp_v6_iif(skb);
1115 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1116 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1117 	if (np->repflow)
1118 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1119 
1120 	/* Clone native IPv6 options from listening socket (if any)
1121 
1122 	   Yes, keeping reference count would be much more clever,
1123 	   but we make one more one thing there: reattach optmem
1124 	   to newsk.
1125 	 */
1126 	opt = ireq->ipv6_opt;
1127 	if (!opt)
1128 		opt = rcu_dereference(np->opt);
1129 	if (opt) {
1130 		opt = ipv6_dup_options(newsk, opt);
1131 		RCU_INIT_POINTER(newnp->opt, opt);
1132 	}
1133 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1134 	if (opt)
1135 		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1136 						    opt->opt_flen;
1137 
1138 	tcp_ca_openreq_child(newsk, dst);
1139 
1140 	tcp_sync_mss(newsk, dst_mtu(dst));
1141 	newtp->advmss = dst_metric_advmss(dst);
1142 	if (tcp_sk(sk)->rx_opt.user_mss &&
1143 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1144 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1145 
1146 	tcp_initialize_rcv_mss(newsk);
1147 
1148 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1149 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1150 
1151 #ifdef CONFIG_TCP_MD5SIG
1152 	/* Copy over the MD5 key from the original socket */
1153 	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1154 	if (key) {
1155 		/* We're using one, so create a matching key
1156 		 * on the newsk structure. If we fail to get
1157 		 * memory, then we end up not copying the key
1158 		 * across. Shucks.
1159 		 */
1160 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1161 			       AF_INET6, key->key, key->keylen,
1162 			       sk_gfp_mask(sk, GFP_ATOMIC));
1163 	}
1164 #endif
1165 
1166 	if (__inet_inherit_port(sk, newsk) < 0) {
1167 		inet_csk_prepare_forced_close(newsk);
1168 		tcp_done(newsk);
1169 		goto out;
1170 	}
1171 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1172 	if (*own_req) {
1173 		tcp_move_syn(newtp, req);
1174 
1175 		/* Clone pktoptions received with SYN, if we own the req */
1176 		if (ireq->pktopts) {
1177 			newnp->pktoptions = skb_clone(ireq->pktopts,
1178 						      sk_gfp_mask(sk, GFP_ATOMIC));
1179 			consume_skb(ireq->pktopts);
1180 			ireq->pktopts = NULL;
1181 			if (newnp->pktoptions)
1182 				skb_set_owner_r(newnp->pktoptions, newsk);
1183 		}
1184 	}
1185 
1186 	return newsk;
1187 
1188 out_overflow:
1189 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1190 out_nonewsk:
1191 	dst_release(dst);
1192 out:
1193 	tcp_listendrop(sk);
1194 	return NULL;
1195 }
1196 
1197 /* The socket must have it's spinlock held when we get
1198  * here, unless it is a TCP_LISTEN socket.
1199  *
1200  * We have a potential double-lock case here, so even when
1201  * doing backlog processing we use the BH locking scheme.
1202  * This is because we cannot sleep with the original spinlock
1203  * held.
1204  */
1205 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1206 {
1207 	struct ipv6_pinfo *np = inet6_sk(sk);
1208 	struct tcp_sock *tp;
1209 	struct sk_buff *opt_skb = NULL;
1210 
1211 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1212 	   goes to IPv4 receive handler and backlogged.
1213 	   From backlog it always goes here. Kerboom...
1214 	   Fortunately, tcp_rcv_established and rcv_established
1215 	   handle them correctly, but it is not case with
1216 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1217 	 */
1218 
1219 	if (skb->protocol == htons(ETH_P_IP))
1220 		return tcp_v4_do_rcv(sk, skb);
1221 
1222 	if (sk_filter(sk, skb))
1223 		goto discard;
1224 
1225 	/*
1226 	 *	socket locking is here for SMP purposes as backlog rcv
1227 	 *	is currently called with bh processing disabled.
1228 	 */
1229 
1230 	/* Do Stevens' IPV6_PKTOPTIONS.
1231 
1232 	   Yes, guys, it is the only place in our code, where we
1233 	   may make it not affecting IPv4.
1234 	   The rest of code is protocol independent,
1235 	   and I do not like idea to uglify IPv4.
1236 
1237 	   Actually, all the idea behind IPV6_PKTOPTIONS
1238 	   looks not very well thought. For now we latch
1239 	   options, received in the last packet, enqueued
1240 	   by tcp. Feel free to propose better solution.
1241 					       --ANK (980728)
1242 	 */
1243 	if (np->rxopt.all)
1244 		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1245 
1246 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1247 		struct dst_entry *dst = sk->sk_rx_dst;
1248 
1249 		sock_rps_save_rxhash(sk, skb);
1250 		sk_mark_napi_id(sk, skb);
1251 		if (dst) {
1252 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1253 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1254 				dst_release(dst);
1255 				sk->sk_rx_dst = NULL;
1256 			}
1257 		}
1258 
1259 		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1260 		if (opt_skb)
1261 			goto ipv6_pktoptions;
1262 		return 0;
1263 	}
1264 
1265 	if (tcp_checksum_complete(skb))
1266 		goto csum_err;
1267 
1268 	if (sk->sk_state == TCP_LISTEN) {
1269 		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1270 
1271 		if (!nsk)
1272 			goto discard;
1273 
1274 		if (nsk != sk) {
1275 			sock_rps_save_rxhash(nsk, skb);
1276 			sk_mark_napi_id(nsk, skb);
1277 			if (tcp_child_process(sk, nsk, skb))
1278 				goto reset;
1279 			if (opt_skb)
1280 				__kfree_skb(opt_skb);
1281 			return 0;
1282 		}
1283 	} else
1284 		sock_rps_save_rxhash(sk, skb);
1285 
1286 	if (tcp_rcv_state_process(sk, skb))
1287 		goto reset;
1288 	if (opt_skb)
1289 		goto ipv6_pktoptions;
1290 	return 0;
1291 
1292 reset:
1293 	tcp_v6_send_reset(sk, skb);
1294 discard:
1295 	if (opt_skb)
1296 		__kfree_skb(opt_skb);
1297 	kfree_skb(skb);
1298 	return 0;
1299 csum_err:
1300 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1301 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1302 	goto discard;
1303 
1304 
1305 ipv6_pktoptions:
1306 	/* Do you ask, what is it?
1307 
1308 	   1. skb was enqueued by tcp.
1309 	   2. skb is added to tail of read queue, rather than out of order.
1310 	   3. socket is not in passive state.
1311 	   4. Finally, it really contains options, which user wants to receive.
1312 	 */
1313 	tp = tcp_sk(sk);
1314 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1315 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1316 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1317 			np->mcast_oif = tcp_v6_iif(opt_skb);
1318 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1319 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1320 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1321 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1322 		if (np->repflow)
1323 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1324 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1325 			skb_set_owner_r(opt_skb, sk);
1326 			opt_skb = xchg(&np->pktoptions, opt_skb);
1327 		} else {
1328 			__kfree_skb(opt_skb);
1329 			opt_skb = xchg(&np->pktoptions, NULL);
1330 		}
1331 	}
1332 
1333 	kfree_skb(opt_skb);
1334 	return 0;
1335 }
1336 
1337 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1338 			   const struct tcphdr *th)
1339 {
1340 	/* This is tricky: we move IP6CB at its correct location into
1341 	 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1342 	 * _decode_session6() uses IP6CB().
1343 	 * barrier() makes sure compiler won't play aliasing games.
1344 	 */
1345 	memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1346 		sizeof(struct inet6_skb_parm));
1347 	barrier();
1348 
1349 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1350 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1351 				    skb->len - th->doff*4);
1352 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1353 	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1354 	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1355 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1356 	TCP_SKB_CB(skb)->sacked = 0;
1357 }
1358 
1359 static void tcp_v6_restore_cb(struct sk_buff *skb)
1360 {
1361 	/* We need to move header back to the beginning if xfrm6_policy_check()
1362 	 * and tcp_v6_fill_cb() are going to be called again.
1363 	 */
1364 	memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1365 		sizeof(struct inet6_skb_parm));
1366 }
1367 
1368 static int tcp_v6_rcv(struct sk_buff *skb)
1369 {
1370 	const struct tcphdr *th;
1371 	const struct ipv6hdr *hdr;
1372 	bool refcounted;
1373 	struct sock *sk;
1374 	int ret;
1375 	struct net *net = dev_net(skb->dev);
1376 
1377 	if (skb->pkt_type != PACKET_HOST)
1378 		goto discard_it;
1379 
1380 	/*
1381 	 *	Count it even if it's bad.
1382 	 */
1383 	__TCP_INC_STATS(net, TCP_MIB_INSEGS);
1384 
1385 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1386 		goto discard_it;
1387 
1388 	th = (const struct tcphdr *)skb->data;
1389 
1390 	if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1391 		goto bad_packet;
1392 	if (!pskb_may_pull(skb, th->doff*4))
1393 		goto discard_it;
1394 
1395 	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1396 		goto csum_error;
1397 
1398 	th = (const struct tcphdr *)skb->data;
1399 	hdr = ipv6_hdr(skb);
1400 
1401 lookup:
1402 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1403 				th->source, th->dest, inet6_iif(skb),
1404 				&refcounted);
1405 	if (!sk)
1406 		goto no_tcp_socket;
1407 
1408 process:
1409 	if (sk->sk_state == TCP_TIME_WAIT)
1410 		goto do_time_wait;
1411 
1412 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
1413 		struct request_sock *req = inet_reqsk(sk);
1414 		struct sock *nsk;
1415 
1416 		sk = req->rsk_listener;
1417 		tcp_v6_fill_cb(skb, hdr, th);
1418 		if (tcp_v6_inbound_md5_hash(sk, skb)) {
1419 			sk_drops_add(sk, skb);
1420 			reqsk_put(req);
1421 			goto discard_it;
1422 		}
1423 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
1424 			inet_csk_reqsk_queue_drop_and_put(sk, req);
1425 			goto lookup;
1426 		}
1427 		sock_hold(sk);
1428 		refcounted = true;
1429 		nsk = tcp_check_req(sk, skb, req, false);
1430 		if (!nsk) {
1431 			reqsk_put(req);
1432 			goto discard_and_relse;
1433 		}
1434 		if (nsk == sk) {
1435 			reqsk_put(req);
1436 			tcp_v6_restore_cb(skb);
1437 		} else if (tcp_child_process(sk, nsk, skb)) {
1438 			tcp_v6_send_reset(nsk, skb);
1439 			goto discard_and_relse;
1440 		} else {
1441 			sock_put(sk);
1442 			return 0;
1443 		}
1444 	}
1445 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1446 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1447 		goto discard_and_relse;
1448 	}
1449 
1450 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1451 		goto discard_and_relse;
1452 
1453 	tcp_v6_fill_cb(skb, hdr, th);
1454 
1455 	if (tcp_v6_inbound_md5_hash(sk, skb))
1456 		goto discard_and_relse;
1457 
1458 	if (sk_filter(sk, skb))
1459 		goto discard_and_relse;
1460 
1461 	skb->dev = NULL;
1462 
1463 	if (sk->sk_state == TCP_LISTEN) {
1464 		ret = tcp_v6_do_rcv(sk, skb);
1465 		goto put_and_return;
1466 	}
1467 
1468 	sk_incoming_cpu_update(sk);
1469 
1470 	bh_lock_sock_nested(sk);
1471 	tcp_segs_in(tcp_sk(sk), skb);
1472 	ret = 0;
1473 	if (!sock_owned_by_user(sk)) {
1474 		if (!tcp_prequeue(sk, skb))
1475 			ret = tcp_v6_do_rcv(sk, skb);
1476 	} else if (tcp_add_backlog(sk, skb)) {
1477 		goto discard_and_relse;
1478 	}
1479 	bh_unlock_sock(sk);
1480 
1481 put_and_return:
1482 	if (refcounted)
1483 		sock_put(sk);
1484 	return ret ? -1 : 0;
1485 
1486 no_tcp_socket:
1487 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1488 		goto discard_it;
1489 
1490 	tcp_v6_fill_cb(skb, hdr, th);
1491 
1492 	if (tcp_checksum_complete(skb)) {
1493 csum_error:
1494 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1495 bad_packet:
1496 		__TCP_INC_STATS(net, TCP_MIB_INERRS);
1497 	} else {
1498 		tcp_v6_send_reset(NULL, skb);
1499 	}
1500 
1501 discard_it:
1502 	kfree_skb(skb);
1503 	return 0;
1504 
1505 discard_and_relse:
1506 	sk_drops_add(sk, skb);
1507 	if (refcounted)
1508 		sock_put(sk);
1509 	goto discard_it;
1510 
1511 do_time_wait:
1512 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1513 		inet_twsk_put(inet_twsk(sk));
1514 		goto discard_it;
1515 	}
1516 
1517 	tcp_v6_fill_cb(skb, hdr, th);
1518 
1519 	if (tcp_checksum_complete(skb)) {
1520 		inet_twsk_put(inet_twsk(sk));
1521 		goto csum_error;
1522 	}
1523 
1524 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1525 	case TCP_TW_SYN:
1526 	{
1527 		struct sock *sk2;
1528 
1529 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1530 					    skb, __tcp_hdrlen(th),
1531 					    &ipv6_hdr(skb)->saddr, th->source,
1532 					    &ipv6_hdr(skb)->daddr,
1533 					    ntohs(th->dest), tcp_v6_iif(skb));
1534 		if (sk2) {
1535 			struct inet_timewait_sock *tw = inet_twsk(sk);
1536 			inet_twsk_deschedule_put(tw);
1537 			sk = sk2;
1538 			tcp_v6_restore_cb(skb);
1539 			refcounted = false;
1540 			goto process;
1541 		}
1542 		/* Fall through to ACK */
1543 	}
1544 	case TCP_TW_ACK:
1545 		tcp_v6_timewait_ack(sk, skb);
1546 		break;
1547 	case TCP_TW_RST:
1548 		tcp_v6_restore_cb(skb);
1549 		tcp_v6_send_reset(sk, skb);
1550 		inet_twsk_deschedule_put(inet_twsk(sk));
1551 		goto discard_it;
1552 	case TCP_TW_SUCCESS:
1553 		;
1554 	}
1555 	goto discard_it;
1556 }
1557 
1558 static void tcp_v6_early_demux(struct sk_buff *skb)
1559 {
1560 	const struct ipv6hdr *hdr;
1561 	const struct tcphdr *th;
1562 	struct sock *sk;
1563 
1564 	if (skb->pkt_type != PACKET_HOST)
1565 		return;
1566 
1567 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1568 		return;
1569 
1570 	hdr = ipv6_hdr(skb);
1571 	th = tcp_hdr(skb);
1572 
1573 	if (th->doff < sizeof(struct tcphdr) / 4)
1574 		return;
1575 
1576 	/* Note : We use inet6_iif() here, not tcp_v6_iif() */
1577 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1578 					&hdr->saddr, th->source,
1579 					&hdr->daddr, ntohs(th->dest),
1580 					inet6_iif(skb));
1581 	if (sk) {
1582 		skb->sk = sk;
1583 		skb->destructor = sock_edemux;
1584 		if (sk_fullsock(sk)) {
1585 			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1586 
1587 			if (dst)
1588 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1589 			if (dst &&
1590 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1591 				skb_dst_set_noref(skb, dst);
1592 		}
1593 	}
1594 }
1595 
1596 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1597 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1598 	.twsk_unique	= tcp_twsk_unique,
1599 	.twsk_destructor = tcp_twsk_destructor,
1600 };
1601 
1602 static const struct inet_connection_sock_af_ops ipv6_specific = {
1603 	.queue_xmit	   = inet6_csk_xmit,
1604 	.send_check	   = tcp_v6_send_check,
1605 	.rebuild_header	   = inet6_sk_rebuild_header,
1606 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1607 	.conn_request	   = tcp_v6_conn_request,
1608 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1609 	.net_header_len	   = sizeof(struct ipv6hdr),
1610 	.net_frag_header_len = sizeof(struct frag_hdr),
1611 	.setsockopt	   = ipv6_setsockopt,
1612 	.getsockopt	   = ipv6_getsockopt,
1613 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1614 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1615 	.bind_conflict	   = inet6_csk_bind_conflict,
1616 #ifdef CONFIG_COMPAT
1617 	.compat_setsockopt = compat_ipv6_setsockopt,
1618 	.compat_getsockopt = compat_ipv6_getsockopt,
1619 #endif
1620 	.mtu_reduced	   = tcp_v6_mtu_reduced,
1621 };
1622 
1623 #ifdef CONFIG_TCP_MD5SIG
1624 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1625 	.md5_lookup	=	tcp_v6_md5_lookup,
1626 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1627 	.md5_parse	=	tcp_v6_parse_md5_keys,
1628 };
1629 #endif
1630 
1631 /*
1632  *	TCP over IPv4 via INET6 API
1633  */
1634 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1635 	.queue_xmit	   = ip_queue_xmit,
1636 	.send_check	   = tcp_v4_send_check,
1637 	.rebuild_header	   = inet_sk_rebuild_header,
1638 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1639 	.conn_request	   = tcp_v6_conn_request,
1640 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1641 	.net_header_len	   = sizeof(struct iphdr),
1642 	.setsockopt	   = ipv6_setsockopt,
1643 	.getsockopt	   = ipv6_getsockopt,
1644 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1645 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1646 	.bind_conflict	   = inet6_csk_bind_conflict,
1647 #ifdef CONFIG_COMPAT
1648 	.compat_setsockopt = compat_ipv6_setsockopt,
1649 	.compat_getsockopt = compat_ipv6_getsockopt,
1650 #endif
1651 	.mtu_reduced	   = tcp_v4_mtu_reduced,
1652 };
1653 
1654 #ifdef CONFIG_TCP_MD5SIG
1655 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1656 	.md5_lookup	=	tcp_v4_md5_lookup,
1657 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1658 	.md5_parse	=	tcp_v6_parse_md5_keys,
1659 };
1660 #endif
1661 
1662 /* NOTE: A lot of things set to zero explicitly by call to
1663  *       sk_alloc() so need not be done here.
1664  */
1665 static int tcp_v6_init_sock(struct sock *sk)
1666 {
1667 	struct inet_connection_sock *icsk = inet_csk(sk);
1668 
1669 	tcp_init_sock(sk);
1670 
1671 	icsk->icsk_af_ops = &ipv6_specific;
1672 
1673 #ifdef CONFIG_TCP_MD5SIG
1674 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1675 #endif
1676 
1677 	return 0;
1678 }
1679 
1680 static void tcp_v6_destroy_sock(struct sock *sk)
1681 {
1682 	tcp_v4_destroy_sock(sk);
1683 	inet6_destroy_sock(sk);
1684 }
1685 
1686 #ifdef CONFIG_PROC_FS
1687 /* Proc filesystem TCPv6 sock list dumping. */
1688 static void get_openreq6(struct seq_file *seq,
1689 			 const struct request_sock *req, int i)
1690 {
1691 	long ttd = req->rsk_timer.expires - jiffies;
1692 	const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1693 	const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1694 
1695 	if (ttd < 0)
1696 		ttd = 0;
1697 
1698 	seq_printf(seq,
1699 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1700 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1701 		   i,
1702 		   src->s6_addr32[0], src->s6_addr32[1],
1703 		   src->s6_addr32[2], src->s6_addr32[3],
1704 		   inet_rsk(req)->ir_num,
1705 		   dest->s6_addr32[0], dest->s6_addr32[1],
1706 		   dest->s6_addr32[2], dest->s6_addr32[3],
1707 		   ntohs(inet_rsk(req)->ir_rmt_port),
1708 		   TCP_SYN_RECV,
1709 		   0, 0, /* could print option size, but that is af dependent. */
1710 		   1,   /* timers active (only the expire timer) */
1711 		   jiffies_to_clock_t(ttd),
1712 		   req->num_timeout,
1713 		   from_kuid_munged(seq_user_ns(seq),
1714 				    sock_i_uid(req->rsk_listener)),
1715 		   0,  /* non standard timer */
1716 		   0, /* open_requests have no inode */
1717 		   0, req);
1718 }
1719 
1720 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1721 {
1722 	const struct in6_addr *dest, *src;
1723 	__u16 destp, srcp;
1724 	int timer_active;
1725 	unsigned long timer_expires;
1726 	const struct inet_sock *inet = inet_sk(sp);
1727 	const struct tcp_sock *tp = tcp_sk(sp);
1728 	const struct inet_connection_sock *icsk = inet_csk(sp);
1729 	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1730 	int rx_queue;
1731 	int state;
1732 
1733 	dest  = &sp->sk_v6_daddr;
1734 	src   = &sp->sk_v6_rcv_saddr;
1735 	destp = ntohs(inet->inet_dport);
1736 	srcp  = ntohs(inet->inet_sport);
1737 
1738 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1739 	    icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1740 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1741 		timer_active	= 1;
1742 		timer_expires	= icsk->icsk_timeout;
1743 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1744 		timer_active	= 4;
1745 		timer_expires	= icsk->icsk_timeout;
1746 	} else if (timer_pending(&sp->sk_timer)) {
1747 		timer_active	= 2;
1748 		timer_expires	= sp->sk_timer.expires;
1749 	} else {
1750 		timer_active	= 0;
1751 		timer_expires = jiffies;
1752 	}
1753 
1754 	state = sk_state_load(sp);
1755 	if (state == TCP_LISTEN)
1756 		rx_queue = sp->sk_ack_backlog;
1757 	else
1758 		/* Because we don't lock the socket,
1759 		 * we might find a transient negative value.
1760 		 */
1761 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1762 
1763 	seq_printf(seq,
1764 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1765 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1766 		   i,
1767 		   src->s6_addr32[0], src->s6_addr32[1],
1768 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1769 		   dest->s6_addr32[0], dest->s6_addr32[1],
1770 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1771 		   state,
1772 		   tp->write_seq - tp->snd_una,
1773 		   rx_queue,
1774 		   timer_active,
1775 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1776 		   icsk->icsk_retransmits,
1777 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1778 		   icsk->icsk_probes_out,
1779 		   sock_i_ino(sp),
1780 		   atomic_read(&sp->sk_refcnt), sp,
1781 		   jiffies_to_clock_t(icsk->icsk_rto),
1782 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1783 		   (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1784 		   tp->snd_cwnd,
1785 		   state == TCP_LISTEN ?
1786 			fastopenq->max_qlen :
1787 			(tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1788 		   );
1789 }
1790 
1791 static void get_timewait6_sock(struct seq_file *seq,
1792 			       struct inet_timewait_sock *tw, int i)
1793 {
1794 	long delta = tw->tw_timer.expires - jiffies;
1795 	const struct in6_addr *dest, *src;
1796 	__u16 destp, srcp;
1797 
1798 	dest = &tw->tw_v6_daddr;
1799 	src  = &tw->tw_v6_rcv_saddr;
1800 	destp = ntohs(tw->tw_dport);
1801 	srcp  = ntohs(tw->tw_sport);
1802 
1803 	seq_printf(seq,
1804 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1805 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1806 		   i,
1807 		   src->s6_addr32[0], src->s6_addr32[1],
1808 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1809 		   dest->s6_addr32[0], dest->s6_addr32[1],
1810 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1811 		   tw->tw_substate, 0, 0,
1812 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1813 		   atomic_read(&tw->tw_refcnt), tw);
1814 }
1815 
1816 static int tcp6_seq_show(struct seq_file *seq, void *v)
1817 {
1818 	struct tcp_iter_state *st;
1819 	struct sock *sk = v;
1820 
1821 	if (v == SEQ_START_TOKEN) {
1822 		seq_puts(seq,
1823 			 "  sl  "
1824 			 "local_address                         "
1825 			 "remote_address                        "
1826 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1827 			 "   uid  timeout inode\n");
1828 		goto out;
1829 	}
1830 	st = seq->private;
1831 
1832 	if (sk->sk_state == TCP_TIME_WAIT)
1833 		get_timewait6_sock(seq, v, st->num);
1834 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
1835 		get_openreq6(seq, v, st->num);
1836 	else
1837 		get_tcp6_sock(seq, v, st->num);
1838 out:
1839 	return 0;
1840 }
1841 
1842 static const struct file_operations tcp6_afinfo_seq_fops = {
1843 	.owner   = THIS_MODULE,
1844 	.open    = tcp_seq_open,
1845 	.read    = seq_read,
1846 	.llseek  = seq_lseek,
1847 	.release = seq_release_net
1848 };
1849 
1850 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1851 	.name		= "tcp6",
1852 	.family		= AF_INET6,
1853 	.seq_fops	= &tcp6_afinfo_seq_fops,
1854 	.seq_ops	= {
1855 		.show		= tcp6_seq_show,
1856 	},
1857 };
1858 
1859 int __net_init tcp6_proc_init(struct net *net)
1860 {
1861 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1862 }
1863 
1864 void tcp6_proc_exit(struct net *net)
1865 {
1866 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1867 }
1868 #endif
1869 
1870 struct proto tcpv6_prot = {
1871 	.name			= "TCPv6",
1872 	.owner			= THIS_MODULE,
1873 	.close			= tcp_close,
1874 	.connect		= tcp_v6_connect,
1875 	.disconnect		= tcp_disconnect,
1876 	.accept			= inet_csk_accept,
1877 	.ioctl			= tcp_ioctl,
1878 	.init			= tcp_v6_init_sock,
1879 	.destroy		= tcp_v6_destroy_sock,
1880 	.shutdown		= tcp_shutdown,
1881 	.setsockopt		= tcp_setsockopt,
1882 	.getsockopt		= tcp_getsockopt,
1883 	.recvmsg		= tcp_recvmsg,
1884 	.sendmsg		= tcp_sendmsg,
1885 	.sendpage		= tcp_sendpage,
1886 	.backlog_rcv		= tcp_v6_do_rcv,
1887 	.release_cb		= tcp_release_cb,
1888 	.hash			= inet6_hash,
1889 	.unhash			= inet_unhash,
1890 	.get_port		= inet_csk_get_port,
1891 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1892 	.stream_memory_free	= tcp_stream_memory_free,
1893 	.sockets_allocated	= &tcp_sockets_allocated,
1894 	.memory_allocated	= &tcp_memory_allocated,
1895 	.memory_pressure	= &tcp_memory_pressure,
1896 	.orphan_count		= &tcp_orphan_count,
1897 	.sysctl_mem		= sysctl_tcp_mem,
1898 	.sysctl_wmem		= sysctl_tcp_wmem,
1899 	.sysctl_rmem		= sysctl_tcp_rmem,
1900 	.max_header		= MAX_TCP_HEADER,
1901 	.obj_size		= sizeof(struct tcp6_sock),
1902 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1903 	.twsk_prot		= &tcp6_timewait_sock_ops,
1904 	.rsk_prot		= &tcp6_request_sock_ops,
1905 	.h.hashinfo		= &tcp_hashinfo,
1906 	.no_autobind		= true,
1907 #ifdef CONFIG_COMPAT
1908 	.compat_setsockopt	= compat_tcp_setsockopt,
1909 	.compat_getsockopt	= compat_tcp_getsockopt,
1910 #endif
1911 	.diag_destroy		= tcp_abort,
1912 };
1913 
1914 static const struct inet6_protocol tcpv6_protocol = {
1915 	.early_demux	=	tcp_v6_early_demux,
1916 	.handler	=	tcp_v6_rcv,
1917 	.err_handler	=	tcp_v6_err,
1918 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1919 };
1920 
1921 static struct inet_protosw tcpv6_protosw = {
1922 	.type		=	SOCK_STREAM,
1923 	.protocol	=	IPPROTO_TCP,
1924 	.prot		=	&tcpv6_prot,
1925 	.ops		=	&inet6_stream_ops,
1926 	.flags		=	INET_PROTOSW_PERMANENT |
1927 				INET_PROTOSW_ICSK,
1928 };
1929 
1930 static int __net_init tcpv6_net_init(struct net *net)
1931 {
1932 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1933 				    SOCK_RAW, IPPROTO_TCP, net);
1934 }
1935 
1936 static void __net_exit tcpv6_net_exit(struct net *net)
1937 {
1938 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1939 }
1940 
1941 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1942 {
1943 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1944 }
1945 
1946 static struct pernet_operations tcpv6_net_ops = {
1947 	.init	    = tcpv6_net_init,
1948 	.exit	    = tcpv6_net_exit,
1949 	.exit_batch = tcpv6_net_exit_batch,
1950 };
1951 
1952 int __init tcpv6_init(void)
1953 {
1954 	int ret;
1955 
1956 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1957 	if (ret)
1958 		goto out;
1959 
1960 	/* register inet6 protocol */
1961 	ret = inet6_register_protosw(&tcpv6_protosw);
1962 	if (ret)
1963 		goto out_tcpv6_protocol;
1964 
1965 	ret = register_pernet_subsys(&tcpv6_net_ops);
1966 	if (ret)
1967 		goto out_tcpv6_protosw;
1968 out:
1969 	return ret;
1970 
1971 out_tcpv6_protosw:
1972 	inet6_unregister_protosw(&tcpv6_protosw);
1973 out_tcpv6_protocol:
1974 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1975 	goto out;
1976 }
1977 
1978 void tcpv6_exit(void)
1979 {
1980 	unregister_pernet_subsys(&tcpv6_net_ops);
1981 	inet6_unregister_protosw(&tcpv6_protosw);
1982 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1983 }
1984