xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision f7777dcc)
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 
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/netdma.h>
63 #include <net/inet_common.h>
64 #include <net/secure_seq.h>
65 #include <net/tcp_memcontrol.h>
66 #include <net/busy_poll.h>
67 
68 #include <asm/uaccess.h>
69 
70 #include <linux/proc_fs.h>
71 #include <linux/seq_file.h>
72 
73 #include <linux/crypto.h>
74 #include <linux/scatterlist.h>
75 
76 static void	tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
77 static void	tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
78 				      struct request_sock *req);
79 
80 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
81 
82 static const struct inet_connection_sock_af_ops ipv6_mapped;
83 static const struct inet_connection_sock_af_ops ipv6_specific;
84 #ifdef CONFIG_TCP_MD5SIG
85 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
86 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
87 #else
88 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
89 						   const struct in6_addr *addr)
90 {
91 	return NULL;
92 }
93 #endif
94 
95 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
96 {
97 	struct dst_entry *dst = skb_dst(skb);
98 	const struct rt6_info *rt = (const struct rt6_info *)dst;
99 
100 	dst_hold(dst);
101 	sk->sk_rx_dst = dst;
102 	inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
103 	if (rt->rt6i_node)
104 		inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
105 }
106 
107 static void tcp_v6_hash(struct sock *sk)
108 {
109 	if (sk->sk_state != TCP_CLOSE) {
110 		if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
111 			tcp_prot.hash(sk);
112 			return;
113 		}
114 		local_bh_disable();
115 		__inet6_hash(sk, NULL);
116 		local_bh_enable();
117 	}
118 }
119 
120 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
121 {
122 	return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
123 					    ipv6_hdr(skb)->saddr.s6_addr32,
124 					    tcp_hdr(skb)->dest,
125 					    tcp_hdr(skb)->source);
126 }
127 
128 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
129 			  int addr_len)
130 {
131 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
132 	struct inet_sock *inet = inet_sk(sk);
133 	struct inet_connection_sock *icsk = inet_csk(sk);
134 	struct ipv6_pinfo *np = inet6_sk(sk);
135 	struct tcp_sock *tp = tcp_sk(sk);
136 	struct in6_addr *saddr = NULL, *final_p, final;
137 	struct rt6_info *rt;
138 	struct flowi6 fl6;
139 	struct dst_entry *dst;
140 	int addr_type;
141 	int err;
142 
143 	if (addr_len < SIN6_LEN_RFC2133)
144 		return -EINVAL;
145 
146 	if (usin->sin6_family != AF_INET6)
147 		return -EAFNOSUPPORT;
148 
149 	memset(&fl6, 0, sizeof(fl6));
150 
151 	if (np->sndflow) {
152 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
153 		IP6_ECN_flow_init(fl6.flowlabel);
154 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
155 			struct ip6_flowlabel *flowlabel;
156 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
157 			if (flowlabel == NULL)
158 				return -EINVAL;
159 			usin->sin6_addr = flowlabel->dst;
160 			fl6_sock_release(flowlabel);
161 		}
162 	}
163 
164 	/*
165 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
166 	 */
167 
168 	if(ipv6_addr_any(&usin->sin6_addr))
169 		usin->sin6_addr.s6_addr[15] = 0x1;
170 
171 	addr_type = ipv6_addr_type(&usin->sin6_addr);
172 
173 	if(addr_type & IPV6_ADDR_MULTICAST)
174 		return -ENETUNREACH;
175 
176 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
177 		if (addr_len >= sizeof(struct sockaddr_in6) &&
178 		    usin->sin6_scope_id) {
179 			/* If interface is set while binding, indices
180 			 * must coincide.
181 			 */
182 			if (sk->sk_bound_dev_if &&
183 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
184 				return -EINVAL;
185 
186 			sk->sk_bound_dev_if = usin->sin6_scope_id;
187 		}
188 
189 		/* Connect to link-local address requires an interface */
190 		if (!sk->sk_bound_dev_if)
191 			return -EINVAL;
192 	}
193 
194 	if (tp->rx_opt.ts_recent_stamp &&
195 	    !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
196 		tp->rx_opt.ts_recent = 0;
197 		tp->rx_opt.ts_recent_stamp = 0;
198 		tp->write_seq = 0;
199 	}
200 
201 	np->daddr = usin->sin6_addr;
202 	np->flow_label = fl6.flowlabel;
203 
204 	/*
205 	 *	TCP over IPv4
206 	 */
207 
208 	if (addr_type == IPV6_ADDR_MAPPED) {
209 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
210 		struct sockaddr_in sin;
211 
212 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
213 
214 		if (__ipv6_only_sock(sk))
215 			return -ENETUNREACH;
216 
217 		sin.sin_family = AF_INET;
218 		sin.sin_port = usin->sin6_port;
219 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
220 
221 		icsk->icsk_af_ops = &ipv6_mapped;
222 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
223 #ifdef CONFIG_TCP_MD5SIG
224 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
225 #endif
226 
227 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
228 
229 		if (err) {
230 			icsk->icsk_ext_hdr_len = exthdrlen;
231 			icsk->icsk_af_ops = &ipv6_specific;
232 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
233 #ifdef CONFIG_TCP_MD5SIG
234 			tp->af_specific = &tcp_sock_ipv6_specific;
235 #endif
236 			goto failure;
237 		} else {
238 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
239 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
240 					       &np->rcv_saddr);
241 		}
242 
243 		return err;
244 	}
245 
246 	if (!ipv6_addr_any(&np->rcv_saddr))
247 		saddr = &np->rcv_saddr;
248 
249 	fl6.flowi6_proto = IPPROTO_TCP;
250 	fl6.daddr = np->daddr;
251 	fl6.saddr = saddr ? *saddr : np->saddr;
252 	fl6.flowi6_oif = sk->sk_bound_dev_if;
253 	fl6.flowi6_mark = sk->sk_mark;
254 	fl6.fl6_dport = usin->sin6_port;
255 	fl6.fl6_sport = inet->inet_sport;
256 
257 	final_p = fl6_update_dst(&fl6, np->opt, &final);
258 
259 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
260 
261 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
262 	if (IS_ERR(dst)) {
263 		err = PTR_ERR(dst);
264 		goto failure;
265 	}
266 
267 	if (saddr == NULL) {
268 		saddr = &fl6.saddr;
269 		np->rcv_saddr = *saddr;
270 	}
271 
272 	/* set the source address */
273 	np->saddr = *saddr;
274 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
275 
276 	sk->sk_gso_type = SKB_GSO_TCPV6;
277 	__ip6_dst_store(sk, dst, NULL, NULL);
278 
279 	rt = (struct rt6_info *) dst;
280 	if (tcp_death_row.sysctl_tw_recycle &&
281 	    !tp->rx_opt.ts_recent_stamp &&
282 	    ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr))
283 		tcp_fetch_timewait_stamp(sk, dst);
284 
285 	icsk->icsk_ext_hdr_len = 0;
286 	if (np->opt)
287 		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
288 					  np->opt->opt_nflen);
289 
290 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
291 
292 	inet->inet_dport = usin->sin6_port;
293 
294 	tcp_set_state(sk, TCP_SYN_SENT);
295 	err = inet6_hash_connect(&tcp_death_row, sk);
296 	if (err)
297 		goto late_failure;
298 
299 	if (!tp->write_seq && likely(!tp->repair))
300 		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
301 							     np->daddr.s6_addr32,
302 							     inet->inet_sport,
303 							     inet->inet_dport);
304 
305 	err = tcp_connect(sk);
306 	if (err)
307 		goto late_failure;
308 
309 	return 0;
310 
311 late_failure:
312 	tcp_set_state(sk, TCP_CLOSE);
313 	__sk_dst_reset(sk);
314 failure:
315 	inet->inet_dport = 0;
316 	sk->sk_route_caps = 0;
317 	return err;
318 }
319 
320 static void tcp_v6_mtu_reduced(struct sock *sk)
321 {
322 	struct dst_entry *dst;
323 
324 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
325 		return;
326 
327 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
328 	if (!dst)
329 		return;
330 
331 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
332 		tcp_sync_mss(sk, dst_mtu(dst));
333 		tcp_simple_retransmit(sk);
334 	}
335 }
336 
337 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
338 		u8 type, u8 code, int offset, __be32 info)
339 {
340 	const struct ipv6hdr *hdr = (const struct ipv6hdr*)skb->data;
341 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
342 	struct ipv6_pinfo *np;
343 	struct sock *sk;
344 	int err;
345 	struct tcp_sock *tp;
346 	__u32 seq;
347 	struct net *net = dev_net(skb->dev);
348 
349 	sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
350 			th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
351 
352 	if (sk == NULL) {
353 		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
354 				   ICMP6_MIB_INERRORS);
355 		return;
356 	}
357 
358 	if (sk->sk_state == TCP_TIME_WAIT) {
359 		inet_twsk_put(inet_twsk(sk));
360 		return;
361 	}
362 
363 	bh_lock_sock(sk);
364 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
365 		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
366 
367 	if (sk->sk_state == TCP_CLOSE)
368 		goto out;
369 
370 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
371 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
372 		goto out;
373 	}
374 
375 	tp = tcp_sk(sk);
376 	seq = ntohl(th->seq);
377 	if (sk->sk_state != TCP_LISTEN &&
378 	    !between(seq, tp->snd_una, tp->snd_nxt)) {
379 		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
380 		goto out;
381 	}
382 
383 	np = inet6_sk(sk);
384 
385 	if (type == NDISC_REDIRECT) {
386 		struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
387 
388 		if (dst)
389 			dst->ops->redirect(dst, sk, skb);
390 		goto out;
391 	}
392 
393 	if (type == ICMPV6_PKT_TOOBIG) {
394 		/* We are not interested in TCP_LISTEN and open_requests
395 		 * (SYN-ACKs send out by Linux are always <576bytes so
396 		 * they should go through unfragmented).
397 		 */
398 		if (sk->sk_state == TCP_LISTEN)
399 			goto out;
400 
401 		tp->mtu_info = ntohl(info);
402 		if (!sock_owned_by_user(sk))
403 			tcp_v6_mtu_reduced(sk);
404 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
405 					   &tp->tsq_flags))
406 			sock_hold(sk);
407 		goto out;
408 	}
409 
410 	icmpv6_err_convert(type, code, &err);
411 
412 	/* Might be for an request_sock */
413 	switch (sk->sk_state) {
414 		struct request_sock *req, **prev;
415 	case TCP_LISTEN:
416 		if (sock_owned_by_user(sk))
417 			goto out;
418 
419 		req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
420 					   &hdr->saddr, inet6_iif(skb));
421 		if (!req)
422 			goto out;
423 
424 		/* ICMPs are not backlogged, hence we cannot get
425 		 * an established socket here.
426 		 */
427 		WARN_ON(req->sk != NULL);
428 
429 		if (seq != tcp_rsk(req)->snt_isn) {
430 			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
431 			goto out;
432 		}
433 
434 		inet_csk_reqsk_queue_drop(sk, req, prev);
435 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
436 		goto out;
437 
438 	case TCP_SYN_SENT:
439 	case TCP_SYN_RECV:  /* Cannot happen.
440 			       It can, it SYNs are crossed. --ANK */
441 		if (!sock_owned_by_user(sk)) {
442 			sk->sk_err = err;
443 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
444 
445 			tcp_done(sk);
446 		} else
447 			sk->sk_err_soft = err;
448 		goto out;
449 	}
450 
451 	if (!sock_owned_by_user(sk) && np->recverr) {
452 		sk->sk_err = err;
453 		sk->sk_error_report(sk);
454 	} else
455 		sk->sk_err_soft = err;
456 
457 out:
458 	bh_unlock_sock(sk);
459 	sock_put(sk);
460 }
461 
462 
463 static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
464 			      struct flowi6 *fl6,
465 			      struct request_sock *req,
466 			      u16 queue_mapping)
467 {
468 	struct inet6_request_sock *treq = inet6_rsk(req);
469 	struct ipv6_pinfo *np = inet6_sk(sk);
470 	struct sk_buff * skb;
471 	int err = -ENOMEM;
472 
473 	/* First, grab a route. */
474 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
475 		goto done;
476 
477 	skb = tcp_make_synack(sk, dst, req, NULL);
478 
479 	if (skb) {
480 		__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
481 
482 		fl6->daddr = treq->rmt_addr;
483 		skb_set_queue_mapping(skb, queue_mapping);
484 		err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
485 		err = net_xmit_eval(err);
486 	}
487 
488 done:
489 	return err;
490 }
491 
492 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req)
493 {
494 	struct flowi6 fl6;
495 	int res;
496 
497 	res = tcp_v6_send_synack(sk, NULL, &fl6, req, 0);
498 	if (!res)
499 		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
500 	return res;
501 }
502 
503 static void tcp_v6_reqsk_destructor(struct request_sock *req)
504 {
505 	kfree_skb(inet6_rsk(req)->pktopts);
506 }
507 
508 #ifdef CONFIG_TCP_MD5SIG
509 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
510 						   const struct in6_addr *addr)
511 {
512 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
513 }
514 
515 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
516 						struct sock *addr_sk)
517 {
518 	return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
519 }
520 
521 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
522 						      struct request_sock *req)
523 {
524 	return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
525 }
526 
527 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
528 				  int optlen)
529 {
530 	struct tcp_md5sig cmd;
531 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
532 
533 	if (optlen < sizeof(cmd))
534 		return -EINVAL;
535 
536 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
537 		return -EFAULT;
538 
539 	if (sin6->sin6_family != AF_INET6)
540 		return -EINVAL;
541 
542 	if (!cmd.tcpm_keylen) {
543 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
544 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
545 					      AF_INET);
546 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
547 				      AF_INET6);
548 	}
549 
550 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
551 		return -EINVAL;
552 
553 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
554 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
555 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
556 
557 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
558 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
559 }
560 
561 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
562 					const struct in6_addr *daddr,
563 					const struct in6_addr *saddr, int nbytes)
564 {
565 	struct tcp6_pseudohdr *bp;
566 	struct scatterlist sg;
567 
568 	bp = &hp->md5_blk.ip6;
569 	/* 1. TCP pseudo-header (RFC2460) */
570 	bp->saddr = *saddr;
571 	bp->daddr = *daddr;
572 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
573 	bp->len = cpu_to_be32(nbytes);
574 
575 	sg_init_one(&sg, bp, sizeof(*bp));
576 	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
577 }
578 
579 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
580 			       const struct in6_addr *daddr, struct in6_addr *saddr,
581 			       const struct tcphdr *th)
582 {
583 	struct tcp_md5sig_pool *hp;
584 	struct hash_desc *desc;
585 
586 	hp = tcp_get_md5sig_pool();
587 	if (!hp)
588 		goto clear_hash_noput;
589 	desc = &hp->md5_desc;
590 
591 	if (crypto_hash_init(desc))
592 		goto clear_hash;
593 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
594 		goto clear_hash;
595 	if (tcp_md5_hash_header(hp, th))
596 		goto clear_hash;
597 	if (tcp_md5_hash_key(hp, key))
598 		goto clear_hash;
599 	if (crypto_hash_final(desc, md5_hash))
600 		goto clear_hash;
601 
602 	tcp_put_md5sig_pool();
603 	return 0;
604 
605 clear_hash:
606 	tcp_put_md5sig_pool();
607 clear_hash_noput:
608 	memset(md5_hash, 0, 16);
609 	return 1;
610 }
611 
612 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
613 			       const struct sock *sk,
614 			       const struct request_sock *req,
615 			       const struct sk_buff *skb)
616 {
617 	const struct in6_addr *saddr, *daddr;
618 	struct tcp_md5sig_pool *hp;
619 	struct hash_desc *desc;
620 	const struct tcphdr *th = tcp_hdr(skb);
621 
622 	if (sk) {
623 		saddr = &inet6_sk(sk)->saddr;
624 		daddr = &inet6_sk(sk)->daddr;
625 	} else if (req) {
626 		saddr = &inet6_rsk(req)->loc_addr;
627 		daddr = &inet6_rsk(req)->rmt_addr;
628 	} else {
629 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
630 		saddr = &ip6h->saddr;
631 		daddr = &ip6h->daddr;
632 	}
633 
634 	hp = tcp_get_md5sig_pool();
635 	if (!hp)
636 		goto clear_hash_noput;
637 	desc = &hp->md5_desc;
638 
639 	if (crypto_hash_init(desc))
640 		goto clear_hash;
641 
642 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
643 		goto clear_hash;
644 	if (tcp_md5_hash_header(hp, th))
645 		goto clear_hash;
646 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
647 		goto clear_hash;
648 	if (tcp_md5_hash_key(hp, key))
649 		goto clear_hash;
650 	if (crypto_hash_final(desc, md5_hash))
651 		goto clear_hash;
652 
653 	tcp_put_md5sig_pool();
654 	return 0;
655 
656 clear_hash:
657 	tcp_put_md5sig_pool();
658 clear_hash_noput:
659 	memset(md5_hash, 0, 16);
660 	return 1;
661 }
662 
663 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
664 {
665 	const __u8 *hash_location = NULL;
666 	struct tcp_md5sig_key *hash_expected;
667 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
668 	const struct tcphdr *th = tcp_hdr(skb);
669 	int genhash;
670 	u8 newhash[16];
671 
672 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
673 	hash_location = tcp_parse_md5sig_option(th);
674 
675 	/* We've parsed the options - do we have a hash? */
676 	if (!hash_expected && !hash_location)
677 		return 0;
678 
679 	if (hash_expected && !hash_location) {
680 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
681 		return 1;
682 	}
683 
684 	if (!hash_expected && hash_location) {
685 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
686 		return 1;
687 	}
688 
689 	/* check the signature */
690 	genhash = tcp_v6_md5_hash_skb(newhash,
691 				      hash_expected,
692 				      NULL, NULL, skb);
693 
694 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
695 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
696 				     genhash ? "failed" : "mismatch",
697 				     &ip6h->saddr, ntohs(th->source),
698 				     &ip6h->daddr, ntohs(th->dest));
699 		return 1;
700 	}
701 	return 0;
702 }
703 #endif
704 
705 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
706 	.family		=	AF_INET6,
707 	.obj_size	=	sizeof(struct tcp6_request_sock),
708 	.rtx_syn_ack	=	tcp_v6_rtx_synack,
709 	.send_ack	=	tcp_v6_reqsk_send_ack,
710 	.destructor	=	tcp_v6_reqsk_destructor,
711 	.send_reset	=	tcp_v6_send_reset,
712 	.syn_ack_timeout = 	tcp_syn_ack_timeout,
713 };
714 
715 #ifdef CONFIG_TCP_MD5SIG
716 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
717 	.md5_lookup	=	tcp_v6_reqsk_md5_lookup,
718 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
719 };
720 #endif
721 
722 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
723 				 u32 tsval, u32 tsecr,
724 				 struct tcp_md5sig_key *key, int rst, u8 tclass)
725 {
726 	const struct tcphdr *th = tcp_hdr(skb);
727 	struct tcphdr *t1;
728 	struct sk_buff *buff;
729 	struct flowi6 fl6;
730 	struct net *net = dev_net(skb_dst(skb)->dev);
731 	struct sock *ctl_sk = net->ipv6.tcp_sk;
732 	unsigned int tot_len = sizeof(struct tcphdr);
733 	struct dst_entry *dst;
734 	__be32 *topt;
735 
736 	if (tsecr)
737 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
738 #ifdef CONFIG_TCP_MD5SIG
739 	if (key)
740 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
741 #endif
742 
743 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
744 			 GFP_ATOMIC);
745 	if (buff == NULL)
746 		return;
747 
748 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
749 
750 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
751 	skb_reset_transport_header(buff);
752 
753 	/* Swap the send and the receive. */
754 	memset(t1, 0, sizeof(*t1));
755 	t1->dest = th->source;
756 	t1->source = th->dest;
757 	t1->doff = tot_len / 4;
758 	t1->seq = htonl(seq);
759 	t1->ack_seq = htonl(ack);
760 	t1->ack = !rst || !th->ack;
761 	t1->rst = rst;
762 	t1->window = htons(win);
763 
764 	topt = (__be32 *)(t1 + 1);
765 
766 	if (tsecr) {
767 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
768 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
769 		*topt++ = htonl(tsval);
770 		*topt++ = htonl(tsecr);
771 	}
772 
773 #ifdef CONFIG_TCP_MD5SIG
774 	if (key) {
775 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
776 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
777 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
778 				    &ipv6_hdr(skb)->saddr,
779 				    &ipv6_hdr(skb)->daddr, t1);
780 	}
781 #endif
782 
783 	memset(&fl6, 0, sizeof(fl6));
784 	fl6.daddr = ipv6_hdr(skb)->saddr;
785 	fl6.saddr = ipv6_hdr(skb)->daddr;
786 
787 	buff->ip_summed = CHECKSUM_PARTIAL;
788 	buff->csum = 0;
789 
790 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
791 
792 	fl6.flowi6_proto = IPPROTO_TCP;
793 	if (ipv6_addr_type(&fl6.daddr) & IPV6_ADDR_LINKLOCAL)
794 		fl6.flowi6_oif = inet6_iif(skb);
795 	fl6.fl6_dport = t1->dest;
796 	fl6.fl6_sport = t1->source;
797 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
798 
799 	/* Pass a socket to ip6_dst_lookup either it is for RST
800 	 * Underlying function will use this to retrieve the network
801 	 * namespace
802 	 */
803 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
804 	if (!IS_ERR(dst)) {
805 		skb_dst_set(buff, dst);
806 		ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
807 		TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
808 		if (rst)
809 			TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
810 		return;
811 	}
812 
813 	kfree_skb(buff);
814 }
815 
816 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
817 {
818 	const struct tcphdr *th = tcp_hdr(skb);
819 	u32 seq = 0, ack_seq = 0;
820 	struct tcp_md5sig_key *key = NULL;
821 #ifdef CONFIG_TCP_MD5SIG
822 	const __u8 *hash_location = NULL;
823 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
824 	unsigned char newhash[16];
825 	int genhash;
826 	struct sock *sk1 = NULL;
827 #endif
828 
829 	if (th->rst)
830 		return;
831 
832 	if (!ipv6_unicast_destination(skb))
833 		return;
834 
835 #ifdef CONFIG_TCP_MD5SIG
836 	hash_location = tcp_parse_md5sig_option(th);
837 	if (!sk && hash_location) {
838 		/*
839 		 * active side is lost. Try to find listening socket through
840 		 * source port, and then find md5 key through listening socket.
841 		 * we are not loose security here:
842 		 * Incoming packet is checked with md5 hash with finding key,
843 		 * no RST generated if md5 hash doesn't match.
844 		 */
845 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
846 					   &tcp_hashinfo, &ipv6h->saddr,
847 					   th->source, &ipv6h->daddr,
848 					   ntohs(th->source), inet6_iif(skb));
849 		if (!sk1)
850 			return;
851 
852 		rcu_read_lock();
853 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
854 		if (!key)
855 			goto release_sk1;
856 
857 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, NULL, skb);
858 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
859 			goto release_sk1;
860 	} else {
861 		key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
862 	}
863 #endif
864 
865 	if (th->ack)
866 		seq = ntohl(th->ack_seq);
867 	else
868 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
869 			  (th->doff << 2);
870 
871 	tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, key, 1, 0);
872 
873 #ifdef CONFIG_TCP_MD5SIG
874 release_sk1:
875 	if (sk1) {
876 		rcu_read_unlock();
877 		sock_put(sk1);
878 	}
879 #endif
880 }
881 
882 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
883 			    u32 win, u32 tsval, u32 tsecr,
884 			    struct tcp_md5sig_key *key, u8 tclass)
885 {
886 	tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, key, 0, tclass);
887 }
888 
889 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
890 {
891 	struct inet_timewait_sock *tw = inet_twsk(sk);
892 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
893 
894 	tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
895 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
896 			tcp_time_stamp + tcptw->tw_ts_offset,
897 			tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
898 			tw->tw_tclass);
899 
900 	inet_twsk_put(tw);
901 }
902 
903 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
904 				  struct request_sock *req)
905 {
906 	tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1,
907 			req->rcv_wnd, tcp_time_stamp, req->ts_recent,
908 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
909 }
910 
911 
912 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
913 {
914 	struct request_sock *req, **prev;
915 	const struct tcphdr *th = tcp_hdr(skb);
916 	struct sock *nsk;
917 
918 	/* Find possible connection requests. */
919 	req = inet6_csk_search_req(sk, &prev, th->source,
920 				   &ipv6_hdr(skb)->saddr,
921 				   &ipv6_hdr(skb)->daddr, inet6_iif(skb));
922 	if (req)
923 		return tcp_check_req(sk, skb, req, prev, false);
924 
925 	nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
926 			&ipv6_hdr(skb)->saddr, th->source,
927 			&ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
928 
929 	if (nsk) {
930 		if (nsk->sk_state != TCP_TIME_WAIT) {
931 			bh_lock_sock(nsk);
932 			return nsk;
933 		}
934 		inet_twsk_put(inet_twsk(nsk));
935 		return NULL;
936 	}
937 
938 #ifdef CONFIG_SYN_COOKIES
939 	if (!th->syn)
940 		sk = cookie_v6_check(sk, skb);
941 #endif
942 	return sk;
943 }
944 
945 /* FIXME: this is substantially similar to the ipv4 code.
946  * Can some kind of merge be done? -- erics
947  */
948 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
949 {
950 	struct tcp_options_received tmp_opt;
951 	struct request_sock *req;
952 	struct inet6_request_sock *treq;
953 	struct ipv6_pinfo *np = inet6_sk(sk);
954 	struct tcp_sock *tp = tcp_sk(sk);
955 	__u32 isn = TCP_SKB_CB(skb)->when;
956 	struct dst_entry *dst = NULL;
957 	struct flowi6 fl6;
958 	bool want_cookie = false;
959 
960 	if (skb->protocol == htons(ETH_P_IP))
961 		return tcp_v4_conn_request(sk, skb);
962 
963 	if (!ipv6_unicast_destination(skb))
964 		goto drop;
965 
966 	if ((sysctl_tcp_syncookies == 2 ||
967 	     inet_csk_reqsk_queue_is_full(sk)) && !isn) {
968 		want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
969 		if (!want_cookie)
970 			goto drop;
971 	}
972 
973 	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
974 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
975 		goto drop;
976 	}
977 
978 	req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
979 	if (req == NULL)
980 		goto drop;
981 
982 #ifdef CONFIG_TCP_MD5SIG
983 	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
984 #endif
985 
986 	tcp_clear_options(&tmp_opt);
987 	tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
988 	tmp_opt.user_mss = tp->rx_opt.user_mss;
989 	tcp_parse_options(skb, &tmp_opt, 0, NULL);
990 
991 	if (want_cookie && !tmp_opt.saw_tstamp)
992 		tcp_clear_options(&tmp_opt);
993 
994 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
995 	tcp_openreq_init(req, &tmp_opt, skb);
996 
997 	treq = inet6_rsk(req);
998 	treq->rmt_addr = ipv6_hdr(skb)->saddr;
999 	treq->loc_addr = ipv6_hdr(skb)->daddr;
1000 	if (!want_cookie || tmp_opt.tstamp_ok)
1001 		TCP_ECN_create_request(req, skb, sock_net(sk));
1002 
1003 	treq->iif = sk->sk_bound_dev_if;
1004 
1005 	/* So that link locals have meaning */
1006 	if (!sk->sk_bound_dev_if &&
1007 	    ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1008 		treq->iif = inet6_iif(skb);
1009 
1010 	if (!isn) {
1011 		if (ipv6_opt_accepted(sk, skb) ||
1012 		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1013 		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1014 			atomic_inc(&skb->users);
1015 			treq->pktopts = skb;
1016 		}
1017 
1018 		if (want_cookie) {
1019 			isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1020 			req->cookie_ts = tmp_opt.tstamp_ok;
1021 			goto have_isn;
1022 		}
1023 
1024 		/* VJ's idea. We save last timestamp seen
1025 		 * from the destination in peer table, when entering
1026 		 * state TIME-WAIT, and check against it before
1027 		 * accepting new connection request.
1028 		 *
1029 		 * If "isn" is not zero, this request hit alive
1030 		 * timewait bucket, so that all the necessary checks
1031 		 * are made in the function processing timewait state.
1032 		 */
1033 		if (tmp_opt.saw_tstamp &&
1034 		    tcp_death_row.sysctl_tw_recycle &&
1035 		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
1036 			if (!tcp_peer_is_proven(req, dst, true)) {
1037 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1038 				goto drop_and_release;
1039 			}
1040 		}
1041 		/* Kill the following clause, if you dislike this way. */
1042 		else if (!sysctl_tcp_syncookies &&
1043 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1044 			  (sysctl_max_syn_backlog >> 2)) &&
1045 			 !tcp_peer_is_proven(req, dst, false)) {
1046 			/* Without syncookies last quarter of
1047 			 * backlog is filled with destinations,
1048 			 * proven to be alive.
1049 			 * It means that we continue to communicate
1050 			 * to destinations, already remembered
1051 			 * to the moment of synflood.
1052 			 */
1053 			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1054 				       &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1055 			goto drop_and_release;
1056 		}
1057 
1058 		isn = tcp_v6_init_sequence(skb);
1059 	}
1060 have_isn:
1061 	tcp_rsk(req)->snt_isn = isn;
1062 
1063 	if (security_inet_conn_request(sk, skb, req))
1064 		goto drop_and_release;
1065 
1066 	if (tcp_v6_send_synack(sk, dst, &fl6, req,
1067 			       skb_get_queue_mapping(skb)) ||
1068 	    want_cookie)
1069 		goto drop_and_free;
1070 
1071 	tcp_rsk(req)->snt_synack = tcp_time_stamp;
1072 	tcp_rsk(req)->listener = NULL;
1073 	inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1074 	return 0;
1075 
1076 drop_and_release:
1077 	dst_release(dst);
1078 drop_and_free:
1079 	reqsk_free(req);
1080 drop:
1081 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1082 	return 0; /* don't send reset */
1083 }
1084 
1085 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1086 					  struct request_sock *req,
1087 					  struct dst_entry *dst)
1088 {
1089 	struct inet6_request_sock *treq;
1090 	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1091 	struct tcp6_sock *newtcp6sk;
1092 	struct inet_sock *newinet;
1093 	struct tcp_sock *newtp;
1094 	struct sock *newsk;
1095 #ifdef CONFIG_TCP_MD5SIG
1096 	struct tcp_md5sig_key *key;
1097 #endif
1098 	struct flowi6 fl6;
1099 
1100 	if (skb->protocol == htons(ETH_P_IP)) {
1101 		/*
1102 		 *	v6 mapped
1103 		 */
1104 
1105 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1106 
1107 		if (newsk == NULL)
1108 			return NULL;
1109 
1110 		newtcp6sk = (struct tcp6_sock *)newsk;
1111 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1112 
1113 		newinet = inet_sk(newsk);
1114 		newnp = inet6_sk(newsk);
1115 		newtp = tcp_sk(newsk);
1116 
1117 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1118 
1119 		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1120 
1121 		ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1122 
1123 		newnp->rcv_saddr = newnp->saddr;
1124 
1125 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1126 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1127 #ifdef CONFIG_TCP_MD5SIG
1128 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1129 #endif
1130 
1131 		newnp->ipv6_ac_list = NULL;
1132 		newnp->ipv6_fl_list = NULL;
1133 		newnp->pktoptions  = NULL;
1134 		newnp->opt	   = NULL;
1135 		newnp->mcast_oif   = inet6_iif(skb);
1136 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1137 		newnp->rcv_tclass  = ipv6_get_dsfield(ipv6_hdr(skb));
1138 
1139 		/*
1140 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1141 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1142 		 * that function for the gory details. -acme
1143 		 */
1144 
1145 		/* It is tricky place. Until this moment IPv4 tcp
1146 		   worked with IPv6 icsk.icsk_af_ops.
1147 		   Sync it now.
1148 		 */
1149 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1150 
1151 		return newsk;
1152 	}
1153 
1154 	treq = inet6_rsk(req);
1155 
1156 	if (sk_acceptq_is_full(sk))
1157 		goto out_overflow;
1158 
1159 	if (!dst) {
1160 		dst = inet6_csk_route_req(sk, &fl6, req);
1161 		if (!dst)
1162 			goto out;
1163 	}
1164 
1165 	newsk = tcp_create_openreq_child(sk, req, skb);
1166 	if (newsk == NULL)
1167 		goto out_nonewsk;
1168 
1169 	/*
1170 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1171 	 * count here, tcp_create_openreq_child now does this for us, see the
1172 	 * comment in that function for the gory details. -acme
1173 	 */
1174 
1175 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1176 	__ip6_dst_store(newsk, dst, NULL, NULL);
1177 	inet6_sk_rx_dst_set(newsk, skb);
1178 
1179 	newtcp6sk = (struct tcp6_sock *)newsk;
1180 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1181 
1182 	newtp = tcp_sk(newsk);
1183 	newinet = inet_sk(newsk);
1184 	newnp = inet6_sk(newsk);
1185 
1186 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1187 
1188 	newnp->daddr = treq->rmt_addr;
1189 	newnp->saddr = treq->loc_addr;
1190 	newnp->rcv_saddr = treq->loc_addr;
1191 	newsk->sk_bound_dev_if = treq->iif;
1192 
1193 	/* Now IPv6 options...
1194 
1195 	   First: no IPv4 options.
1196 	 */
1197 	newinet->inet_opt = NULL;
1198 	newnp->ipv6_ac_list = NULL;
1199 	newnp->ipv6_fl_list = NULL;
1200 
1201 	/* Clone RX bits */
1202 	newnp->rxopt.all = np->rxopt.all;
1203 
1204 	/* Clone pktoptions received with SYN */
1205 	newnp->pktoptions = NULL;
1206 	if (treq->pktopts != NULL) {
1207 		newnp->pktoptions = skb_clone(treq->pktopts,
1208 					      sk_gfp_atomic(sk, GFP_ATOMIC));
1209 		consume_skb(treq->pktopts);
1210 		treq->pktopts = NULL;
1211 		if (newnp->pktoptions)
1212 			skb_set_owner_r(newnp->pktoptions, newsk);
1213 	}
1214 	newnp->opt	  = NULL;
1215 	newnp->mcast_oif  = inet6_iif(skb);
1216 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1217 	newnp->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
1218 
1219 	/* Clone native IPv6 options from listening socket (if any)
1220 
1221 	   Yes, keeping reference count would be much more clever,
1222 	   but we make one more one thing there: reattach optmem
1223 	   to newsk.
1224 	 */
1225 	if (np->opt)
1226 		newnp->opt = ipv6_dup_options(newsk, np->opt);
1227 
1228 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1229 	if (newnp->opt)
1230 		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1231 						     newnp->opt->opt_flen);
1232 
1233 	tcp_mtup_init(newsk);
1234 	tcp_sync_mss(newsk, dst_mtu(dst));
1235 	newtp->advmss = dst_metric_advmss(dst);
1236 	if (tcp_sk(sk)->rx_opt.user_mss &&
1237 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1238 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1239 
1240 	tcp_initialize_rcv_mss(newsk);
1241 
1242 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1243 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1244 
1245 #ifdef CONFIG_TCP_MD5SIG
1246 	/* Copy over the MD5 key from the original socket */
1247 	if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1248 		/* We're using one, so create a matching key
1249 		 * on the newsk structure. If we fail to get
1250 		 * memory, then we end up not copying the key
1251 		 * across. Shucks.
1252 		 */
1253 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1254 			       AF_INET6, key->key, key->keylen,
1255 			       sk_gfp_atomic(sk, GFP_ATOMIC));
1256 	}
1257 #endif
1258 
1259 	if (__inet_inherit_port(sk, newsk) < 0) {
1260 		inet_csk_prepare_forced_close(newsk);
1261 		tcp_done(newsk);
1262 		goto out;
1263 	}
1264 	__inet6_hash(newsk, NULL);
1265 
1266 	return newsk;
1267 
1268 out_overflow:
1269 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1270 out_nonewsk:
1271 	dst_release(dst);
1272 out:
1273 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1274 	return NULL;
1275 }
1276 
1277 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1278 {
1279 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
1280 		if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1281 				  &ipv6_hdr(skb)->daddr, skb->csum)) {
1282 			skb->ip_summed = CHECKSUM_UNNECESSARY;
1283 			return 0;
1284 		}
1285 	}
1286 
1287 	skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1288 					      &ipv6_hdr(skb)->saddr,
1289 					      &ipv6_hdr(skb)->daddr, 0));
1290 
1291 	if (skb->len <= 76) {
1292 		return __skb_checksum_complete(skb);
1293 	}
1294 	return 0;
1295 }
1296 
1297 /* The socket must have it's spinlock held when we get
1298  * here.
1299  *
1300  * We have a potential double-lock case here, so even when
1301  * doing backlog processing we use the BH locking scheme.
1302  * This is because we cannot sleep with the original spinlock
1303  * held.
1304  */
1305 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1306 {
1307 	struct ipv6_pinfo *np = inet6_sk(sk);
1308 	struct tcp_sock *tp;
1309 	struct sk_buff *opt_skb = NULL;
1310 
1311 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1312 	   goes to IPv4 receive handler and backlogged.
1313 	   From backlog it always goes here. Kerboom...
1314 	   Fortunately, tcp_rcv_established and rcv_established
1315 	   handle them correctly, but it is not case with
1316 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1317 	 */
1318 
1319 	if (skb->protocol == htons(ETH_P_IP))
1320 		return tcp_v4_do_rcv(sk, skb);
1321 
1322 #ifdef CONFIG_TCP_MD5SIG
1323 	if (tcp_v6_inbound_md5_hash (sk, skb))
1324 		goto discard;
1325 #endif
1326 
1327 	if (sk_filter(sk, skb))
1328 		goto discard;
1329 
1330 	/*
1331 	 *	socket locking is here for SMP purposes as backlog rcv
1332 	 *	is currently called with bh processing disabled.
1333 	 */
1334 
1335 	/* Do Stevens' IPV6_PKTOPTIONS.
1336 
1337 	   Yes, guys, it is the only place in our code, where we
1338 	   may make it not affecting IPv4.
1339 	   The rest of code is protocol independent,
1340 	   and I do not like idea to uglify IPv4.
1341 
1342 	   Actually, all the idea behind IPV6_PKTOPTIONS
1343 	   looks not very well thought. For now we latch
1344 	   options, received in the last packet, enqueued
1345 	   by tcp. Feel free to propose better solution.
1346 					       --ANK (980728)
1347 	 */
1348 	if (np->rxopt.all)
1349 		opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1350 
1351 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1352 		struct dst_entry *dst = sk->sk_rx_dst;
1353 
1354 		sock_rps_save_rxhash(sk, skb);
1355 		if (dst) {
1356 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1357 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1358 				dst_release(dst);
1359 				sk->sk_rx_dst = NULL;
1360 			}
1361 		}
1362 
1363 		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1364 		if (opt_skb)
1365 			goto ipv6_pktoptions;
1366 		return 0;
1367 	}
1368 
1369 	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1370 		goto csum_err;
1371 
1372 	if (sk->sk_state == TCP_LISTEN) {
1373 		struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1374 		if (!nsk)
1375 			goto discard;
1376 
1377 		/*
1378 		 * Queue it on the new socket if the new socket is active,
1379 		 * otherwise we just shortcircuit this and continue with
1380 		 * the new socket..
1381 		 */
1382 		if(nsk != sk) {
1383 			sock_rps_save_rxhash(nsk, skb);
1384 			if (tcp_child_process(sk, nsk, skb))
1385 				goto reset;
1386 			if (opt_skb)
1387 				__kfree_skb(opt_skb);
1388 			return 0;
1389 		}
1390 	} else
1391 		sock_rps_save_rxhash(sk, skb);
1392 
1393 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1394 		goto reset;
1395 	if (opt_skb)
1396 		goto ipv6_pktoptions;
1397 	return 0;
1398 
1399 reset:
1400 	tcp_v6_send_reset(sk, skb);
1401 discard:
1402 	if (opt_skb)
1403 		__kfree_skb(opt_skb);
1404 	kfree_skb(skb);
1405 	return 0;
1406 csum_err:
1407 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1408 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1409 	goto discard;
1410 
1411 
1412 ipv6_pktoptions:
1413 	/* Do you ask, what is it?
1414 
1415 	   1. skb was enqueued by tcp.
1416 	   2. skb is added to tail of read queue, rather than out of order.
1417 	   3. socket is not in passive state.
1418 	   4. Finally, it really contains options, which user wants to receive.
1419 	 */
1420 	tp = tcp_sk(sk);
1421 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1422 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1423 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1424 			np->mcast_oif = inet6_iif(opt_skb);
1425 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1426 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1427 		if (np->rxopt.bits.rxtclass)
1428 			np->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(opt_skb));
1429 		if (ipv6_opt_accepted(sk, opt_skb)) {
1430 			skb_set_owner_r(opt_skb, sk);
1431 			opt_skb = xchg(&np->pktoptions, opt_skb);
1432 		} else {
1433 			__kfree_skb(opt_skb);
1434 			opt_skb = xchg(&np->pktoptions, NULL);
1435 		}
1436 	}
1437 
1438 	kfree_skb(opt_skb);
1439 	return 0;
1440 }
1441 
1442 static int tcp_v6_rcv(struct sk_buff *skb)
1443 {
1444 	const struct tcphdr *th;
1445 	const struct ipv6hdr *hdr;
1446 	struct sock *sk;
1447 	int ret;
1448 	struct net *net = dev_net(skb->dev);
1449 
1450 	if (skb->pkt_type != PACKET_HOST)
1451 		goto discard_it;
1452 
1453 	/*
1454 	 *	Count it even if it's bad.
1455 	 */
1456 	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1457 
1458 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1459 		goto discard_it;
1460 
1461 	th = tcp_hdr(skb);
1462 
1463 	if (th->doff < sizeof(struct tcphdr)/4)
1464 		goto bad_packet;
1465 	if (!pskb_may_pull(skb, th->doff*4))
1466 		goto discard_it;
1467 
1468 	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1469 		goto csum_error;
1470 
1471 	th = tcp_hdr(skb);
1472 	hdr = ipv6_hdr(skb);
1473 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1474 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1475 				    skb->len - th->doff*4);
1476 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1477 	TCP_SKB_CB(skb)->when = 0;
1478 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1479 	TCP_SKB_CB(skb)->sacked = 0;
1480 
1481 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1482 	if (!sk)
1483 		goto no_tcp_socket;
1484 
1485 process:
1486 	if (sk->sk_state == TCP_TIME_WAIT)
1487 		goto do_time_wait;
1488 
1489 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1490 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1491 		goto discard_and_relse;
1492 	}
1493 
1494 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1495 		goto discard_and_relse;
1496 
1497 	if (sk_filter(sk, skb))
1498 		goto discard_and_relse;
1499 
1500 	sk_mark_napi_id(sk, skb);
1501 	skb->dev = NULL;
1502 
1503 	bh_lock_sock_nested(sk);
1504 	ret = 0;
1505 	if (!sock_owned_by_user(sk)) {
1506 #ifdef CONFIG_NET_DMA
1507 		struct tcp_sock *tp = tcp_sk(sk);
1508 		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1509 			tp->ucopy.dma_chan = net_dma_find_channel();
1510 		if (tp->ucopy.dma_chan)
1511 			ret = tcp_v6_do_rcv(sk, skb);
1512 		else
1513 #endif
1514 		{
1515 			if (!tcp_prequeue(sk, skb))
1516 				ret = tcp_v6_do_rcv(sk, skb);
1517 		}
1518 	} else if (unlikely(sk_add_backlog(sk, skb,
1519 					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
1520 		bh_unlock_sock(sk);
1521 		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1522 		goto discard_and_relse;
1523 	}
1524 	bh_unlock_sock(sk);
1525 
1526 	sock_put(sk);
1527 	return ret ? -1 : 0;
1528 
1529 no_tcp_socket:
1530 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1531 		goto discard_it;
1532 
1533 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1534 csum_error:
1535 		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1536 bad_packet:
1537 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1538 	} else {
1539 		tcp_v6_send_reset(NULL, skb);
1540 	}
1541 
1542 discard_it:
1543 	kfree_skb(skb);
1544 	return 0;
1545 
1546 discard_and_relse:
1547 	sock_put(sk);
1548 	goto discard_it;
1549 
1550 do_time_wait:
1551 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1552 		inet_twsk_put(inet_twsk(sk));
1553 		goto discard_it;
1554 	}
1555 
1556 	if (skb->len < (th->doff<<2)) {
1557 		inet_twsk_put(inet_twsk(sk));
1558 		goto bad_packet;
1559 	}
1560 	if (tcp_checksum_complete(skb)) {
1561 		inet_twsk_put(inet_twsk(sk));
1562 		goto csum_error;
1563 	}
1564 
1565 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1566 	case TCP_TW_SYN:
1567 	{
1568 		struct sock *sk2;
1569 
1570 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1571 					    &ipv6_hdr(skb)->saddr, th->source,
1572 					    &ipv6_hdr(skb)->daddr,
1573 					    ntohs(th->dest), inet6_iif(skb));
1574 		if (sk2 != NULL) {
1575 			struct inet_timewait_sock *tw = inet_twsk(sk);
1576 			inet_twsk_deschedule(tw, &tcp_death_row);
1577 			inet_twsk_put(tw);
1578 			sk = sk2;
1579 			goto process;
1580 		}
1581 		/* Fall through to ACK */
1582 	}
1583 	case TCP_TW_ACK:
1584 		tcp_v6_timewait_ack(sk, skb);
1585 		break;
1586 	case TCP_TW_RST:
1587 		goto no_tcp_socket;
1588 	case TCP_TW_SUCCESS:;
1589 	}
1590 	goto discard_it;
1591 }
1592 
1593 static void tcp_v6_early_demux(struct sk_buff *skb)
1594 {
1595 	const struct ipv6hdr *hdr;
1596 	const struct tcphdr *th;
1597 	struct sock *sk;
1598 
1599 	if (skb->pkt_type != PACKET_HOST)
1600 		return;
1601 
1602 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1603 		return;
1604 
1605 	hdr = ipv6_hdr(skb);
1606 	th = tcp_hdr(skb);
1607 
1608 	if (th->doff < sizeof(struct tcphdr) / 4)
1609 		return;
1610 
1611 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1612 					&hdr->saddr, th->source,
1613 					&hdr->daddr, ntohs(th->dest),
1614 					inet6_iif(skb));
1615 	if (sk) {
1616 		skb->sk = sk;
1617 		skb->destructor = sock_edemux;
1618 		if (sk->sk_state != TCP_TIME_WAIT) {
1619 			struct dst_entry *dst = sk->sk_rx_dst;
1620 
1621 			if (dst)
1622 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1623 			if (dst &&
1624 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1625 				skb_dst_set_noref(skb, dst);
1626 		}
1627 	}
1628 }
1629 
1630 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1631 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1632 	.twsk_unique	= tcp_twsk_unique,
1633 	.twsk_destructor= tcp_twsk_destructor,
1634 };
1635 
1636 static const struct inet_connection_sock_af_ops ipv6_specific = {
1637 	.queue_xmit	   = inet6_csk_xmit,
1638 	.send_check	   = tcp_v6_send_check,
1639 	.rebuild_header	   = inet6_sk_rebuild_header,
1640 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1641 	.conn_request	   = tcp_v6_conn_request,
1642 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1643 	.net_header_len	   = sizeof(struct ipv6hdr),
1644 	.net_frag_header_len = sizeof(struct frag_hdr),
1645 	.setsockopt	   = ipv6_setsockopt,
1646 	.getsockopt	   = ipv6_getsockopt,
1647 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1648 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1649 	.bind_conflict	   = inet6_csk_bind_conflict,
1650 #ifdef CONFIG_COMPAT
1651 	.compat_setsockopt = compat_ipv6_setsockopt,
1652 	.compat_getsockopt = compat_ipv6_getsockopt,
1653 #endif
1654 };
1655 
1656 #ifdef CONFIG_TCP_MD5SIG
1657 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1658 	.md5_lookup	=	tcp_v6_md5_lookup,
1659 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1660 	.md5_parse	=	tcp_v6_parse_md5_keys,
1661 };
1662 #endif
1663 
1664 /*
1665  *	TCP over IPv4 via INET6 API
1666  */
1667 
1668 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1669 	.queue_xmit	   = ip_queue_xmit,
1670 	.send_check	   = tcp_v4_send_check,
1671 	.rebuild_header	   = inet_sk_rebuild_header,
1672 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1673 	.conn_request	   = tcp_v6_conn_request,
1674 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1675 	.net_header_len	   = sizeof(struct iphdr),
1676 	.setsockopt	   = ipv6_setsockopt,
1677 	.getsockopt	   = ipv6_getsockopt,
1678 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1679 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1680 	.bind_conflict	   = inet6_csk_bind_conflict,
1681 #ifdef CONFIG_COMPAT
1682 	.compat_setsockopt = compat_ipv6_setsockopt,
1683 	.compat_getsockopt = compat_ipv6_getsockopt,
1684 #endif
1685 };
1686 
1687 #ifdef CONFIG_TCP_MD5SIG
1688 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1689 	.md5_lookup	=	tcp_v4_md5_lookup,
1690 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1691 	.md5_parse	=	tcp_v6_parse_md5_keys,
1692 };
1693 #endif
1694 
1695 /* NOTE: A lot of things set to zero explicitly by call to
1696  *       sk_alloc() so need not be done here.
1697  */
1698 static int tcp_v6_init_sock(struct sock *sk)
1699 {
1700 	struct inet_connection_sock *icsk = inet_csk(sk);
1701 
1702 	tcp_init_sock(sk);
1703 
1704 	icsk->icsk_af_ops = &ipv6_specific;
1705 
1706 #ifdef CONFIG_TCP_MD5SIG
1707 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1708 #endif
1709 
1710 	return 0;
1711 }
1712 
1713 static void tcp_v6_destroy_sock(struct sock *sk)
1714 {
1715 	tcp_v4_destroy_sock(sk);
1716 	inet6_destroy_sock(sk);
1717 }
1718 
1719 #ifdef CONFIG_PROC_FS
1720 /* Proc filesystem TCPv6 sock list dumping. */
1721 static void get_openreq6(struct seq_file *seq,
1722 			 const struct sock *sk, struct request_sock *req, int i, kuid_t uid)
1723 {
1724 	int ttd = req->expires - jiffies;
1725 	const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1726 	const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1727 
1728 	if (ttd < 0)
1729 		ttd = 0;
1730 
1731 	seq_printf(seq,
1732 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1733 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1734 		   i,
1735 		   src->s6_addr32[0], src->s6_addr32[1],
1736 		   src->s6_addr32[2], src->s6_addr32[3],
1737 		   ntohs(inet_rsk(req)->loc_port),
1738 		   dest->s6_addr32[0], dest->s6_addr32[1],
1739 		   dest->s6_addr32[2], dest->s6_addr32[3],
1740 		   ntohs(inet_rsk(req)->rmt_port),
1741 		   TCP_SYN_RECV,
1742 		   0,0, /* could print option size, but that is af dependent. */
1743 		   1,   /* timers active (only the expire timer) */
1744 		   jiffies_to_clock_t(ttd),
1745 		   req->num_timeout,
1746 		   from_kuid_munged(seq_user_ns(seq), uid),
1747 		   0,  /* non standard timer */
1748 		   0, /* open_requests have no inode */
1749 		   0, req);
1750 }
1751 
1752 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1753 {
1754 	const struct in6_addr *dest, *src;
1755 	__u16 destp, srcp;
1756 	int timer_active;
1757 	unsigned long timer_expires;
1758 	const struct inet_sock *inet = inet_sk(sp);
1759 	const struct tcp_sock *tp = tcp_sk(sp);
1760 	const struct inet_connection_sock *icsk = inet_csk(sp);
1761 	const struct ipv6_pinfo *np = inet6_sk(sp);
1762 
1763 	dest  = &np->daddr;
1764 	src   = &np->rcv_saddr;
1765 	destp = ntohs(inet->inet_dport);
1766 	srcp  = ntohs(inet->inet_sport);
1767 
1768 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1769 		timer_active	= 1;
1770 		timer_expires	= icsk->icsk_timeout;
1771 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1772 		timer_active	= 4;
1773 		timer_expires	= icsk->icsk_timeout;
1774 	} else if (timer_pending(&sp->sk_timer)) {
1775 		timer_active	= 2;
1776 		timer_expires	= sp->sk_timer.expires;
1777 	} else {
1778 		timer_active	= 0;
1779 		timer_expires = jiffies;
1780 	}
1781 
1782 	seq_printf(seq,
1783 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1784 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1785 		   i,
1786 		   src->s6_addr32[0], src->s6_addr32[1],
1787 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1788 		   dest->s6_addr32[0], dest->s6_addr32[1],
1789 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1790 		   sp->sk_state,
1791 		   tp->write_seq-tp->snd_una,
1792 		   (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1793 		   timer_active,
1794 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1795 		   icsk->icsk_retransmits,
1796 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1797 		   icsk->icsk_probes_out,
1798 		   sock_i_ino(sp),
1799 		   atomic_read(&sp->sk_refcnt), sp,
1800 		   jiffies_to_clock_t(icsk->icsk_rto),
1801 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1802 		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1803 		   tp->snd_cwnd,
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 	const struct in6_addr *dest, *src;
1812 	__u16 destp, srcp;
1813 	const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1814 	long delta = tw->tw_ttd - jiffies;
1815 
1816 	dest = &tw6->tw_v6_daddr;
1817 	src  = &tw6->tw_v6_rcv_saddr;
1818 	destp = ntohs(tw->tw_dport);
1819 	srcp  = ntohs(tw->tw_sport);
1820 
1821 	seq_printf(seq,
1822 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1823 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1824 		   i,
1825 		   src->s6_addr32[0], src->s6_addr32[1],
1826 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1827 		   dest->s6_addr32[0], dest->s6_addr32[1],
1828 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1829 		   tw->tw_substate, 0, 0,
1830 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1831 		   atomic_read(&tw->tw_refcnt), tw);
1832 }
1833 
1834 static int tcp6_seq_show(struct seq_file *seq, void *v)
1835 {
1836 	struct tcp_iter_state *st;
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 	switch (st->state) {
1850 	case TCP_SEQ_STATE_LISTENING:
1851 	case TCP_SEQ_STATE_ESTABLISHED:
1852 		get_tcp6_sock(seq, v, st->num);
1853 		break;
1854 	case TCP_SEQ_STATE_OPENREQ:
1855 		get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
1856 		break;
1857 	case TCP_SEQ_STATE_TIME_WAIT:
1858 		get_timewait6_sock(seq, v, st->num);
1859 		break;
1860 	}
1861 out:
1862 	return 0;
1863 }
1864 
1865 static const struct file_operations tcp6_afinfo_seq_fops = {
1866 	.owner   = THIS_MODULE,
1867 	.open    = tcp_seq_open,
1868 	.read    = seq_read,
1869 	.llseek  = seq_lseek,
1870 	.release = seq_release_net
1871 };
1872 
1873 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1874 	.name		= "tcp6",
1875 	.family		= AF_INET6,
1876 	.seq_fops	= &tcp6_afinfo_seq_fops,
1877 	.seq_ops	= {
1878 		.show		= tcp6_seq_show,
1879 	},
1880 };
1881 
1882 int __net_init tcp6_proc_init(struct net *net)
1883 {
1884 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1885 }
1886 
1887 void tcp6_proc_exit(struct net *net)
1888 {
1889 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1890 }
1891 #endif
1892 
1893 static void tcp_v6_clear_sk(struct sock *sk, int size)
1894 {
1895 	struct inet_sock *inet = inet_sk(sk);
1896 
1897 	/* we do not want to clear pinet6 field, because of RCU lookups */
1898 	sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1899 
1900 	size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1901 	memset(&inet->pinet6 + 1, 0, size);
1902 }
1903 
1904 struct proto tcpv6_prot = {
1905 	.name			= "TCPv6",
1906 	.owner			= THIS_MODULE,
1907 	.close			= tcp_close,
1908 	.connect		= tcp_v6_connect,
1909 	.disconnect		= tcp_disconnect,
1910 	.accept			= inet_csk_accept,
1911 	.ioctl			= tcp_ioctl,
1912 	.init			= tcp_v6_init_sock,
1913 	.destroy		= tcp_v6_destroy_sock,
1914 	.shutdown		= tcp_shutdown,
1915 	.setsockopt		= tcp_setsockopt,
1916 	.getsockopt		= tcp_getsockopt,
1917 	.recvmsg		= tcp_recvmsg,
1918 	.sendmsg		= tcp_sendmsg,
1919 	.sendpage		= tcp_sendpage,
1920 	.backlog_rcv		= tcp_v6_do_rcv,
1921 	.release_cb		= tcp_release_cb,
1922 	.mtu_reduced		= tcp_v6_mtu_reduced,
1923 	.hash			= tcp_v6_hash,
1924 	.unhash			= inet_unhash,
1925 	.get_port		= inet_csk_get_port,
1926 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1927 	.stream_memory_free	= tcp_stream_memory_free,
1928 	.sockets_allocated	= &tcp_sockets_allocated,
1929 	.memory_allocated	= &tcp_memory_allocated,
1930 	.memory_pressure	= &tcp_memory_pressure,
1931 	.orphan_count		= &tcp_orphan_count,
1932 	.sysctl_wmem		= sysctl_tcp_wmem,
1933 	.sysctl_rmem		= sysctl_tcp_rmem,
1934 	.max_header		= MAX_TCP_HEADER,
1935 	.obj_size		= sizeof(struct tcp6_sock),
1936 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1937 	.twsk_prot		= &tcp6_timewait_sock_ops,
1938 	.rsk_prot		= &tcp6_request_sock_ops,
1939 	.h.hashinfo		= &tcp_hashinfo,
1940 	.no_autobind		= true,
1941 #ifdef CONFIG_COMPAT
1942 	.compat_setsockopt	= compat_tcp_setsockopt,
1943 	.compat_getsockopt	= compat_tcp_getsockopt,
1944 #endif
1945 #ifdef CONFIG_MEMCG_KMEM
1946 	.proto_cgroup		= tcp_proto_cgroup,
1947 #endif
1948 	.clear_sk		= tcp_v6_clear_sk,
1949 };
1950 
1951 static const struct inet6_protocol tcpv6_protocol = {
1952 	.early_demux	=	tcp_v6_early_demux,
1953 	.handler	=	tcp_v6_rcv,
1954 	.err_handler	=	tcp_v6_err,
1955 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1956 };
1957 
1958 static struct inet_protosw tcpv6_protosw = {
1959 	.type		=	SOCK_STREAM,
1960 	.protocol	=	IPPROTO_TCP,
1961 	.prot		=	&tcpv6_prot,
1962 	.ops		=	&inet6_stream_ops,
1963 	.no_check	=	0,
1964 	.flags		=	INET_PROTOSW_PERMANENT |
1965 				INET_PROTOSW_ICSK,
1966 };
1967 
1968 static int __net_init tcpv6_net_init(struct net *net)
1969 {
1970 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1971 				    SOCK_RAW, IPPROTO_TCP, net);
1972 }
1973 
1974 static void __net_exit tcpv6_net_exit(struct net *net)
1975 {
1976 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1977 }
1978 
1979 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1980 {
1981 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1982 }
1983 
1984 static struct pernet_operations tcpv6_net_ops = {
1985 	.init	    = tcpv6_net_init,
1986 	.exit	    = tcpv6_net_exit,
1987 	.exit_batch = tcpv6_net_exit_batch,
1988 };
1989 
1990 int __init tcpv6_init(void)
1991 {
1992 	int ret;
1993 
1994 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1995 	if (ret)
1996 		goto out;
1997 
1998 	/* register inet6 protocol */
1999 	ret = inet6_register_protosw(&tcpv6_protosw);
2000 	if (ret)
2001 		goto out_tcpv6_protocol;
2002 
2003 	ret = register_pernet_subsys(&tcpv6_net_ops);
2004 	if (ret)
2005 		goto out_tcpv6_protosw;
2006 out:
2007 	return ret;
2008 
2009 out_tcpv6_protosw:
2010 	inet6_unregister_protosw(&tcpv6_protosw);
2011 out_tcpv6_protocol:
2012 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2013 	goto out;
2014 }
2015 
2016 void tcpv6_exit(void)
2017 {
2018 	unregister_pernet_subsys(&tcpv6_net_ops);
2019 	inet6_unregister_protosw(&tcpv6_protosw);
2020 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2021 }
2022