xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision ee8a99bd)
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 (inet_csk_reqsk_queue_is_full(sk) && !isn) {
967 		want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
968 		if (!want_cookie)
969 			goto drop;
970 	}
971 
972 	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
973 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
974 		goto drop;
975 	}
976 
977 	req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
978 	if (req == NULL)
979 		goto drop;
980 
981 #ifdef CONFIG_TCP_MD5SIG
982 	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
983 #endif
984 
985 	tcp_clear_options(&tmp_opt);
986 	tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
987 	tmp_opt.user_mss = tp->rx_opt.user_mss;
988 	tcp_parse_options(skb, &tmp_opt, 0, NULL);
989 
990 	if (want_cookie && !tmp_opt.saw_tstamp)
991 		tcp_clear_options(&tmp_opt);
992 
993 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
994 	tcp_openreq_init(req, &tmp_opt, skb);
995 
996 	treq = inet6_rsk(req);
997 	treq->rmt_addr = ipv6_hdr(skb)->saddr;
998 	treq->loc_addr = ipv6_hdr(skb)->daddr;
999 	if (!want_cookie || tmp_opt.tstamp_ok)
1000 		TCP_ECN_create_request(req, skb, sock_net(sk));
1001 
1002 	treq->iif = sk->sk_bound_dev_if;
1003 
1004 	/* So that link locals have meaning */
1005 	if (!sk->sk_bound_dev_if &&
1006 	    ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1007 		treq->iif = inet6_iif(skb);
1008 
1009 	if (!isn) {
1010 		if (ipv6_opt_accepted(sk, skb) ||
1011 		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1012 		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1013 			atomic_inc(&skb->users);
1014 			treq->pktopts = skb;
1015 		}
1016 
1017 		if (want_cookie) {
1018 			isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1019 			req->cookie_ts = tmp_opt.tstamp_ok;
1020 			goto have_isn;
1021 		}
1022 
1023 		/* VJ's idea. We save last timestamp seen
1024 		 * from the destination in peer table, when entering
1025 		 * state TIME-WAIT, and check against it before
1026 		 * accepting new connection request.
1027 		 *
1028 		 * If "isn" is not zero, this request hit alive
1029 		 * timewait bucket, so that all the necessary checks
1030 		 * are made in the function processing timewait state.
1031 		 */
1032 		if (tmp_opt.saw_tstamp &&
1033 		    tcp_death_row.sysctl_tw_recycle &&
1034 		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
1035 			if (!tcp_peer_is_proven(req, dst, true)) {
1036 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1037 				goto drop_and_release;
1038 			}
1039 		}
1040 		/* Kill the following clause, if you dislike this way. */
1041 		else if (!sysctl_tcp_syncookies &&
1042 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1043 			  (sysctl_max_syn_backlog >> 2)) &&
1044 			 !tcp_peer_is_proven(req, dst, false)) {
1045 			/* Without syncookies last quarter of
1046 			 * backlog is filled with destinations,
1047 			 * proven to be alive.
1048 			 * It means that we continue to communicate
1049 			 * to destinations, already remembered
1050 			 * to the moment of synflood.
1051 			 */
1052 			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1053 				       &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1054 			goto drop_and_release;
1055 		}
1056 
1057 		isn = tcp_v6_init_sequence(skb);
1058 	}
1059 have_isn:
1060 	tcp_rsk(req)->snt_isn = isn;
1061 
1062 	if (security_inet_conn_request(sk, skb, req))
1063 		goto drop_and_release;
1064 
1065 	if (tcp_v6_send_synack(sk, dst, &fl6, req,
1066 			       skb_get_queue_mapping(skb)) ||
1067 	    want_cookie)
1068 		goto drop_and_free;
1069 
1070 	tcp_rsk(req)->snt_synack = tcp_time_stamp;
1071 	tcp_rsk(req)->listener = NULL;
1072 	inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1073 	return 0;
1074 
1075 drop_and_release:
1076 	dst_release(dst);
1077 drop_and_free:
1078 	reqsk_free(req);
1079 drop:
1080 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1081 	return 0; /* don't send reset */
1082 }
1083 
1084 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1085 					  struct request_sock *req,
1086 					  struct dst_entry *dst)
1087 {
1088 	struct inet6_request_sock *treq;
1089 	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1090 	struct tcp6_sock *newtcp6sk;
1091 	struct inet_sock *newinet;
1092 	struct tcp_sock *newtp;
1093 	struct sock *newsk;
1094 #ifdef CONFIG_TCP_MD5SIG
1095 	struct tcp_md5sig_key *key;
1096 #endif
1097 	struct flowi6 fl6;
1098 
1099 	if (skb->protocol == htons(ETH_P_IP)) {
1100 		/*
1101 		 *	v6 mapped
1102 		 */
1103 
1104 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1105 
1106 		if (newsk == NULL)
1107 			return NULL;
1108 
1109 		newtcp6sk = (struct tcp6_sock *)newsk;
1110 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1111 
1112 		newinet = inet_sk(newsk);
1113 		newnp = inet6_sk(newsk);
1114 		newtp = tcp_sk(newsk);
1115 
1116 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1117 
1118 		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1119 
1120 		ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1121 
1122 		newnp->rcv_saddr = newnp->saddr;
1123 
1124 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1125 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1126 #ifdef CONFIG_TCP_MD5SIG
1127 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1128 #endif
1129 
1130 		newnp->ipv6_ac_list = NULL;
1131 		newnp->ipv6_fl_list = NULL;
1132 		newnp->pktoptions  = NULL;
1133 		newnp->opt	   = NULL;
1134 		newnp->mcast_oif   = inet6_iif(skb);
1135 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1136 		newnp->rcv_tclass  = ipv6_get_dsfield(ipv6_hdr(skb));
1137 
1138 		/*
1139 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1140 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1141 		 * that function for the gory details. -acme
1142 		 */
1143 
1144 		/* It is tricky place. Until this moment IPv4 tcp
1145 		   worked with IPv6 icsk.icsk_af_ops.
1146 		   Sync it now.
1147 		 */
1148 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1149 
1150 		return newsk;
1151 	}
1152 
1153 	treq = inet6_rsk(req);
1154 
1155 	if (sk_acceptq_is_full(sk))
1156 		goto out_overflow;
1157 
1158 	if (!dst) {
1159 		dst = inet6_csk_route_req(sk, &fl6, req);
1160 		if (!dst)
1161 			goto out;
1162 	}
1163 
1164 	newsk = tcp_create_openreq_child(sk, req, skb);
1165 	if (newsk == NULL)
1166 		goto out_nonewsk;
1167 
1168 	/*
1169 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1170 	 * count here, tcp_create_openreq_child now does this for us, see the
1171 	 * comment in that function for the gory details. -acme
1172 	 */
1173 
1174 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1175 	__ip6_dst_store(newsk, dst, NULL, NULL);
1176 	inet6_sk_rx_dst_set(newsk, skb);
1177 
1178 	newtcp6sk = (struct tcp6_sock *)newsk;
1179 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1180 
1181 	newtp = tcp_sk(newsk);
1182 	newinet = inet_sk(newsk);
1183 	newnp = inet6_sk(newsk);
1184 
1185 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1186 
1187 	newnp->daddr = treq->rmt_addr;
1188 	newnp->saddr = treq->loc_addr;
1189 	newnp->rcv_saddr = treq->loc_addr;
1190 	newsk->sk_bound_dev_if = treq->iif;
1191 
1192 	/* Now IPv6 options...
1193 
1194 	   First: no IPv4 options.
1195 	 */
1196 	newinet->inet_opt = NULL;
1197 	newnp->ipv6_ac_list = NULL;
1198 	newnp->ipv6_fl_list = NULL;
1199 
1200 	/* Clone RX bits */
1201 	newnp->rxopt.all = np->rxopt.all;
1202 
1203 	/* Clone pktoptions received with SYN */
1204 	newnp->pktoptions = NULL;
1205 	if (treq->pktopts != NULL) {
1206 		newnp->pktoptions = skb_clone(treq->pktopts,
1207 					      sk_gfp_atomic(sk, GFP_ATOMIC));
1208 		consume_skb(treq->pktopts);
1209 		treq->pktopts = NULL;
1210 		if (newnp->pktoptions)
1211 			skb_set_owner_r(newnp->pktoptions, newsk);
1212 	}
1213 	newnp->opt	  = NULL;
1214 	newnp->mcast_oif  = inet6_iif(skb);
1215 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1216 	newnp->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
1217 
1218 	/* Clone native IPv6 options from listening socket (if any)
1219 
1220 	   Yes, keeping reference count would be much more clever,
1221 	   but we make one more one thing there: reattach optmem
1222 	   to newsk.
1223 	 */
1224 	if (np->opt)
1225 		newnp->opt = ipv6_dup_options(newsk, np->opt);
1226 
1227 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1228 	if (newnp->opt)
1229 		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1230 						     newnp->opt->opt_flen);
1231 
1232 	tcp_mtup_init(newsk);
1233 	tcp_sync_mss(newsk, dst_mtu(dst));
1234 	newtp->advmss = dst_metric_advmss(dst);
1235 	if (tcp_sk(sk)->rx_opt.user_mss &&
1236 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1237 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1238 
1239 	tcp_initialize_rcv_mss(newsk);
1240 	tcp_synack_rtt_meas(newsk, req);
1241 	newtp->total_retrans = req->num_retrans;
1242 
1243 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1244 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1245 
1246 #ifdef CONFIG_TCP_MD5SIG
1247 	/* Copy over the MD5 key from the original socket */
1248 	if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1249 		/* We're using one, so create a matching key
1250 		 * on the newsk structure. If we fail to get
1251 		 * memory, then we end up not copying the key
1252 		 * across. Shucks.
1253 		 */
1254 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1255 			       AF_INET6, key->key, key->keylen,
1256 			       sk_gfp_atomic(sk, GFP_ATOMIC));
1257 	}
1258 #endif
1259 
1260 	if (__inet_inherit_port(sk, newsk) < 0) {
1261 		inet_csk_prepare_forced_close(newsk);
1262 		tcp_done(newsk);
1263 		goto out;
1264 	}
1265 	__inet6_hash(newsk, NULL);
1266 
1267 	return newsk;
1268 
1269 out_overflow:
1270 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1271 out_nonewsk:
1272 	dst_release(dst);
1273 out:
1274 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1275 	return NULL;
1276 }
1277 
1278 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1279 {
1280 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
1281 		if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1282 				  &ipv6_hdr(skb)->daddr, skb->csum)) {
1283 			skb->ip_summed = CHECKSUM_UNNECESSARY;
1284 			return 0;
1285 		}
1286 	}
1287 
1288 	skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1289 					      &ipv6_hdr(skb)->saddr,
1290 					      &ipv6_hdr(skb)->daddr, 0));
1291 
1292 	if (skb->len <= 76) {
1293 		return __skb_checksum_complete(skb);
1294 	}
1295 	return 0;
1296 }
1297 
1298 /* The socket must have it's spinlock held when we get
1299  * here.
1300  *
1301  * We have a potential double-lock case here, so even when
1302  * doing backlog processing we use the BH locking scheme.
1303  * This is because we cannot sleep with the original spinlock
1304  * held.
1305  */
1306 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1307 {
1308 	struct ipv6_pinfo *np = inet6_sk(sk);
1309 	struct tcp_sock *tp;
1310 	struct sk_buff *opt_skb = NULL;
1311 
1312 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1313 	   goes to IPv4 receive handler and backlogged.
1314 	   From backlog it always goes here. Kerboom...
1315 	   Fortunately, tcp_rcv_established and rcv_established
1316 	   handle them correctly, but it is not case with
1317 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1318 	 */
1319 
1320 	if (skb->protocol == htons(ETH_P_IP))
1321 		return tcp_v4_do_rcv(sk, skb);
1322 
1323 #ifdef CONFIG_TCP_MD5SIG
1324 	if (tcp_v6_inbound_md5_hash (sk, skb))
1325 		goto discard;
1326 #endif
1327 
1328 	if (sk_filter(sk, skb))
1329 		goto discard;
1330 
1331 	/*
1332 	 *	socket locking is here for SMP purposes as backlog rcv
1333 	 *	is currently called with bh processing disabled.
1334 	 */
1335 
1336 	/* Do Stevens' IPV6_PKTOPTIONS.
1337 
1338 	   Yes, guys, it is the only place in our code, where we
1339 	   may make it not affecting IPv4.
1340 	   The rest of code is protocol independent,
1341 	   and I do not like idea to uglify IPv4.
1342 
1343 	   Actually, all the idea behind IPV6_PKTOPTIONS
1344 	   looks not very well thought. For now we latch
1345 	   options, received in the last packet, enqueued
1346 	   by tcp. Feel free to propose better solution.
1347 					       --ANK (980728)
1348 	 */
1349 	if (np->rxopt.all)
1350 		opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1351 
1352 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1353 		struct dst_entry *dst = sk->sk_rx_dst;
1354 
1355 		sock_rps_save_rxhash(sk, skb);
1356 		if (dst) {
1357 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1358 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1359 				dst_release(dst);
1360 				sk->sk_rx_dst = NULL;
1361 			}
1362 		}
1363 
1364 		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1365 			goto reset;
1366 		if (opt_skb)
1367 			goto ipv6_pktoptions;
1368 		return 0;
1369 	}
1370 
1371 	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1372 		goto csum_err;
1373 
1374 	if (sk->sk_state == TCP_LISTEN) {
1375 		struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1376 		if (!nsk)
1377 			goto discard;
1378 
1379 		/*
1380 		 * Queue it on the new socket if the new socket is active,
1381 		 * otherwise we just shortcircuit this and continue with
1382 		 * the new socket..
1383 		 */
1384 		if(nsk != sk) {
1385 			sock_rps_save_rxhash(nsk, skb);
1386 			if (tcp_child_process(sk, nsk, skb))
1387 				goto reset;
1388 			if (opt_skb)
1389 				__kfree_skb(opt_skb);
1390 			return 0;
1391 		}
1392 	} else
1393 		sock_rps_save_rxhash(sk, skb);
1394 
1395 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1396 		goto reset;
1397 	if (opt_skb)
1398 		goto ipv6_pktoptions;
1399 	return 0;
1400 
1401 reset:
1402 	tcp_v6_send_reset(sk, skb);
1403 discard:
1404 	if (opt_skb)
1405 		__kfree_skb(opt_skb);
1406 	kfree_skb(skb);
1407 	return 0;
1408 csum_err:
1409 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1410 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1411 	goto discard;
1412 
1413 
1414 ipv6_pktoptions:
1415 	/* Do you ask, what is it?
1416 
1417 	   1. skb was enqueued by tcp.
1418 	   2. skb is added to tail of read queue, rather than out of order.
1419 	   3. socket is not in passive state.
1420 	   4. Finally, it really contains options, which user wants to receive.
1421 	 */
1422 	tp = tcp_sk(sk);
1423 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1424 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1425 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1426 			np->mcast_oif = inet6_iif(opt_skb);
1427 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1428 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1429 		if (np->rxopt.bits.rxtclass)
1430 			np->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
1431 		if (ipv6_opt_accepted(sk, opt_skb)) {
1432 			skb_set_owner_r(opt_skb, sk);
1433 			opt_skb = xchg(&np->pktoptions, opt_skb);
1434 		} else {
1435 			__kfree_skb(opt_skb);
1436 			opt_skb = xchg(&np->pktoptions, NULL);
1437 		}
1438 	}
1439 
1440 	kfree_skb(opt_skb);
1441 	return 0;
1442 }
1443 
1444 static int tcp_v6_rcv(struct sk_buff *skb)
1445 {
1446 	const struct tcphdr *th;
1447 	const struct ipv6hdr *hdr;
1448 	struct sock *sk;
1449 	int ret;
1450 	struct net *net = dev_net(skb->dev);
1451 
1452 	if (skb->pkt_type != PACKET_HOST)
1453 		goto discard_it;
1454 
1455 	/*
1456 	 *	Count it even if it's bad.
1457 	 */
1458 	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1459 
1460 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1461 		goto discard_it;
1462 
1463 	th = tcp_hdr(skb);
1464 
1465 	if (th->doff < sizeof(struct tcphdr)/4)
1466 		goto bad_packet;
1467 	if (!pskb_may_pull(skb, th->doff*4))
1468 		goto discard_it;
1469 
1470 	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1471 		goto csum_error;
1472 
1473 	th = tcp_hdr(skb);
1474 	hdr = ipv6_hdr(skb);
1475 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1476 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1477 				    skb->len - th->doff*4);
1478 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1479 	TCP_SKB_CB(skb)->when = 0;
1480 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1481 	TCP_SKB_CB(skb)->sacked = 0;
1482 
1483 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1484 	if (!sk)
1485 		goto no_tcp_socket;
1486 
1487 process:
1488 	if (sk->sk_state == TCP_TIME_WAIT)
1489 		goto do_time_wait;
1490 
1491 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1492 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1493 		goto discard_and_relse;
1494 	}
1495 
1496 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1497 		goto discard_and_relse;
1498 
1499 	if (sk_filter(sk, skb))
1500 		goto discard_and_relse;
1501 
1502 	sk_mark_napi_id(sk, skb);
1503 	skb->dev = NULL;
1504 
1505 	bh_lock_sock_nested(sk);
1506 	ret = 0;
1507 	if (!sock_owned_by_user(sk)) {
1508 #ifdef CONFIG_NET_DMA
1509 		struct tcp_sock *tp = tcp_sk(sk);
1510 		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1511 			tp->ucopy.dma_chan = net_dma_find_channel();
1512 		if (tp->ucopy.dma_chan)
1513 			ret = tcp_v6_do_rcv(sk, skb);
1514 		else
1515 #endif
1516 		{
1517 			if (!tcp_prequeue(sk, skb))
1518 				ret = tcp_v6_do_rcv(sk, skb);
1519 		}
1520 	} else if (unlikely(sk_add_backlog(sk, skb,
1521 					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
1522 		bh_unlock_sock(sk);
1523 		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1524 		goto discard_and_relse;
1525 	}
1526 	bh_unlock_sock(sk);
1527 
1528 	sock_put(sk);
1529 	return ret ? -1 : 0;
1530 
1531 no_tcp_socket:
1532 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1533 		goto discard_it;
1534 
1535 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1536 csum_error:
1537 		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1538 bad_packet:
1539 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1540 	} else {
1541 		tcp_v6_send_reset(NULL, skb);
1542 	}
1543 
1544 discard_it:
1545 	kfree_skb(skb);
1546 	return 0;
1547 
1548 discard_and_relse:
1549 	sock_put(sk);
1550 	goto discard_it;
1551 
1552 do_time_wait:
1553 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1554 		inet_twsk_put(inet_twsk(sk));
1555 		goto discard_it;
1556 	}
1557 
1558 	if (skb->len < (th->doff<<2)) {
1559 		inet_twsk_put(inet_twsk(sk));
1560 		goto bad_packet;
1561 	}
1562 	if (tcp_checksum_complete(skb)) {
1563 		inet_twsk_put(inet_twsk(sk));
1564 		goto csum_error;
1565 	}
1566 
1567 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1568 	case TCP_TW_SYN:
1569 	{
1570 		struct sock *sk2;
1571 
1572 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1573 					    &ipv6_hdr(skb)->saddr, th->source,
1574 					    &ipv6_hdr(skb)->daddr,
1575 					    ntohs(th->dest), inet6_iif(skb));
1576 		if (sk2 != NULL) {
1577 			struct inet_timewait_sock *tw = inet_twsk(sk);
1578 			inet_twsk_deschedule(tw, &tcp_death_row);
1579 			inet_twsk_put(tw);
1580 			sk = sk2;
1581 			goto process;
1582 		}
1583 		/* Fall through to ACK */
1584 	}
1585 	case TCP_TW_ACK:
1586 		tcp_v6_timewait_ack(sk, skb);
1587 		break;
1588 	case TCP_TW_RST:
1589 		goto no_tcp_socket;
1590 	case TCP_TW_SUCCESS:;
1591 	}
1592 	goto discard_it;
1593 }
1594 
1595 static void tcp_v6_early_demux(struct sk_buff *skb)
1596 {
1597 	const struct ipv6hdr *hdr;
1598 	const struct tcphdr *th;
1599 	struct sock *sk;
1600 
1601 	if (skb->pkt_type != PACKET_HOST)
1602 		return;
1603 
1604 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1605 		return;
1606 
1607 	hdr = ipv6_hdr(skb);
1608 	th = tcp_hdr(skb);
1609 
1610 	if (th->doff < sizeof(struct tcphdr) / 4)
1611 		return;
1612 
1613 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1614 					&hdr->saddr, th->source,
1615 					&hdr->daddr, ntohs(th->dest),
1616 					inet6_iif(skb));
1617 	if (sk) {
1618 		skb->sk = sk;
1619 		skb->destructor = sock_edemux;
1620 		if (sk->sk_state != TCP_TIME_WAIT) {
1621 			struct dst_entry *dst = sk->sk_rx_dst;
1622 
1623 			if (dst)
1624 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1625 			if (dst &&
1626 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1627 				skb_dst_set_noref(skb, dst);
1628 		}
1629 	}
1630 }
1631 
1632 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1633 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1634 	.twsk_unique	= tcp_twsk_unique,
1635 	.twsk_destructor= tcp_twsk_destructor,
1636 };
1637 
1638 static const struct inet_connection_sock_af_ops ipv6_specific = {
1639 	.queue_xmit	   = inet6_csk_xmit,
1640 	.send_check	   = tcp_v6_send_check,
1641 	.rebuild_header	   = inet6_sk_rebuild_header,
1642 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1643 	.conn_request	   = tcp_v6_conn_request,
1644 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1645 	.net_header_len	   = sizeof(struct ipv6hdr),
1646 	.net_frag_header_len = sizeof(struct frag_hdr),
1647 	.setsockopt	   = ipv6_setsockopt,
1648 	.getsockopt	   = ipv6_getsockopt,
1649 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1650 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1651 	.bind_conflict	   = inet6_csk_bind_conflict,
1652 #ifdef CONFIG_COMPAT
1653 	.compat_setsockopt = compat_ipv6_setsockopt,
1654 	.compat_getsockopt = compat_ipv6_getsockopt,
1655 #endif
1656 };
1657 
1658 #ifdef CONFIG_TCP_MD5SIG
1659 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1660 	.md5_lookup	=	tcp_v6_md5_lookup,
1661 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1662 	.md5_parse	=	tcp_v6_parse_md5_keys,
1663 };
1664 #endif
1665 
1666 /*
1667  *	TCP over IPv4 via INET6 API
1668  */
1669 
1670 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1671 	.queue_xmit	   = ip_queue_xmit,
1672 	.send_check	   = tcp_v4_send_check,
1673 	.rebuild_header	   = inet_sk_rebuild_header,
1674 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1675 	.conn_request	   = tcp_v6_conn_request,
1676 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1677 	.net_header_len	   = sizeof(struct iphdr),
1678 	.setsockopt	   = ipv6_setsockopt,
1679 	.getsockopt	   = ipv6_getsockopt,
1680 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1681 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1682 	.bind_conflict	   = inet6_csk_bind_conflict,
1683 #ifdef CONFIG_COMPAT
1684 	.compat_setsockopt = compat_ipv6_setsockopt,
1685 	.compat_getsockopt = compat_ipv6_getsockopt,
1686 #endif
1687 };
1688 
1689 #ifdef CONFIG_TCP_MD5SIG
1690 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1691 	.md5_lookup	=	tcp_v4_md5_lookup,
1692 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1693 	.md5_parse	=	tcp_v6_parse_md5_keys,
1694 };
1695 #endif
1696 
1697 /* NOTE: A lot of things set to zero explicitly by call to
1698  *       sk_alloc() so need not be done here.
1699  */
1700 static int tcp_v6_init_sock(struct sock *sk)
1701 {
1702 	struct inet_connection_sock *icsk = inet_csk(sk);
1703 
1704 	tcp_init_sock(sk);
1705 
1706 	icsk->icsk_af_ops = &ipv6_specific;
1707 
1708 #ifdef CONFIG_TCP_MD5SIG
1709 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1710 #endif
1711 
1712 	return 0;
1713 }
1714 
1715 static void tcp_v6_destroy_sock(struct sock *sk)
1716 {
1717 	tcp_v4_destroy_sock(sk);
1718 	inet6_destroy_sock(sk);
1719 }
1720 
1721 #ifdef CONFIG_PROC_FS
1722 /* Proc filesystem TCPv6 sock list dumping. */
1723 static void get_openreq6(struct seq_file *seq,
1724 			 const struct sock *sk, struct request_sock *req, int i, kuid_t uid)
1725 {
1726 	int ttd = req->expires - jiffies;
1727 	const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1728 	const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1729 
1730 	if (ttd < 0)
1731 		ttd = 0;
1732 
1733 	seq_printf(seq,
1734 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1735 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1736 		   i,
1737 		   src->s6_addr32[0], src->s6_addr32[1],
1738 		   src->s6_addr32[2], src->s6_addr32[3],
1739 		   ntohs(inet_rsk(req)->loc_port),
1740 		   dest->s6_addr32[0], dest->s6_addr32[1],
1741 		   dest->s6_addr32[2], dest->s6_addr32[3],
1742 		   ntohs(inet_rsk(req)->rmt_port),
1743 		   TCP_SYN_RECV,
1744 		   0,0, /* could print option size, but that is af dependent. */
1745 		   1,   /* timers active (only the expire timer) */
1746 		   jiffies_to_clock_t(ttd),
1747 		   req->num_timeout,
1748 		   from_kuid_munged(seq_user_ns(seq), uid),
1749 		   0,  /* non standard timer */
1750 		   0, /* open_requests have no inode */
1751 		   0, req);
1752 }
1753 
1754 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1755 {
1756 	const struct in6_addr *dest, *src;
1757 	__u16 destp, srcp;
1758 	int timer_active;
1759 	unsigned long timer_expires;
1760 	const struct inet_sock *inet = inet_sk(sp);
1761 	const struct tcp_sock *tp = tcp_sk(sp);
1762 	const struct inet_connection_sock *icsk = inet_csk(sp);
1763 	const struct ipv6_pinfo *np = inet6_sk(sp);
1764 
1765 	dest  = &np->daddr;
1766 	src   = &np->rcv_saddr;
1767 	destp = ntohs(inet->inet_dport);
1768 	srcp  = ntohs(inet->inet_sport);
1769 
1770 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1771 		timer_active	= 1;
1772 		timer_expires	= icsk->icsk_timeout;
1773 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1774 		timer_active	= 4;
1775 		timer_expires	= icsk->icsk_timeout;
1776 	} else if (timer_pending(&sp->sk_timer)) {
1777 		timer_active	= 2;
1778 		timer_expires	= sp->sk_timer.expires;
1779 	} else {
1780 		timer_active	= 0;
1781 		timer_expires = jiffies;
1782 	}
1783 
1784 	seq_printf(seq,
1785 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1786 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
1787 		   i,
1788 		   src->s6_addr32[0], src->s6_addr32[1],
1789 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1790 		   dest->s6_addr32[0], dest->s6_addr32[1],
1791 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1792 		   sp->sk_state,
1793 		   tp->write_seq-tp->snd_una,
1794 		   (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1795 		   timer_active,
1796 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1797 		   icsk->icsk_retransmits,
1798 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1799 		   icsk->icsk_probes_out,
1800 		   sock_i_ino(sp),
1801 		   atomic_read(&sp->sk_refcnt), sp,
1802 		   jiffies_to_clock_t(icsk->icsk_rto),
1803 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1804 		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1805 		   tp->snd_cwnd,
1806 		   tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
1807 		   );
1808 }
1809 
1810 static void get_timewait6_sock(struct seq_file *seq,
1811 			       struct inet_timewait_sock *tw, int i)
1812 {
1813 	const struct in6_addr *dest, *src;
1814 	__u16 destp, srcp;
1815 	const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1816 	long delta = tw->tw_ttd - jiffies;
1817 
1818 	dest = &tw6->tw_v6_daddr;
1819 	src  = &tw6->tw_v6_rcv_saddr;
1820 	destp = ntohs(tw->tw_dport);
1821 	srcp  = ntohs(tw->tw_sport);
1822 
1823 	seq_printf(seq,
1824 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1825 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1826 		   i,
1827 		   src->s6_addr32[0], src->s6_addr32[1],
1828 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1829 		   dest->s6_addr32[0], dest->s6_addr32[1],
1830 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1831 		   tw->tw_substate, 0, 0,
1832 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1833 		   atomic_read(&tw->tw_refcnt), tw);
1834 }
1835 
1836 static int tcp6_seq_show(struct seq_file *seq, void *v)
1837 {
1838 	struct tcp_iter_state *st;
1839 
1840 	if (v == SEQ_START_TOKEN) {
1841 		seq_puts(seq,
1842 			 "  sl  "
1843 			 "local_address                         "
1844 			 "remote_address                        "
1845 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1846 			 "   uid  timeout inode\n");
1847 		goto out;
1848 	}
1849 	st = seq->private;
1850 
1851 	switch (st->state) {
1852 	case TCP_SEQ_STATE_LISTENING:
1853 	case TCP_SEQ_STATE_ESTABLISHED:
1854 		get_tcp6_sock(seq, v, st->num);
1855 		break;
1856 	case TCP_SEQ_STATE_OPENREQ:
1857 		get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
1858 		break;
1859 	case TCP_SEQ_STATE_TIME_WAIT:
1860 		get_timewait6_sock(seq, v, st->num);
1861 		break;
1862 	}
1863 out:
1864 	return 0;
1865 }
1866 
1867 static const struct file_operations tcp6_afinfo_seq_fops = {
1868 	.owner   = THIS_MODULE,
1869 	.open    = tcp_seq_open,
1870 	.read    = seq_read,
1871 	.llseek  = seq_lseek,
1872 	.release = seq_release_net
1873 };
1874 
1875 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1876 	.name		= "tcp6",
1877 	.family		= AF_INET6,
1878 	.seq_fops	= &tcp6_afinfo_seq_fops,
1879 	.seq_ops	= {
1880 		.show		= tcp6_seq_show,
1881 	},
1882 };
1883 
1884 int __net_init tcp6_proc_init(struct net *net)
1885 {
1886 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1887 }
1888 
1889 void tcp6_proc_exit(struct net *net)
1890 {
1891 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1892 }
1893 #endif
1894 
1895 static void tcp_v6_clear_sk(struct sock *sk, int size)
1896 {
1897 	struct inet_sock *inet = inet_sk(sk);
1898 
1899 	/* we do not want to clear pinet6 field, because of RCU lookups */
1900 	sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1901 
1902 	size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1903 	memset(&inet->pinet6 + 1, 0, size);
1904 }
1905 
1906 struct proto tcpv6_prot = {
1907 	.name			= "TCPv6",
1908 	.owner			= THIS_MODULE,
1909 	.close			= tcp_close,
1910 	.connect		= tcp_v6_connect,
1911 	.disconnect		= tcp_disconnect,
1912 	.accept			= inet_csk_accept,
1913 	.ioctl			= tcp_ioctl,
1914 	.init			= tcp_v6_init_sock,
1915 	.destroy		= tcp_v6_destroy_sock,
1916 	.shutdown		= tcp_shutdown,
1917 	.setsockopt		= tcp_setsockopt,
1918 	.getsockopt		= tcp_getsockopt,
1919 	.recvmsg		= tcp_recvmsg,
1920 	.sendmsg		= tcp_sendmsg,
1921 	.sendpage		= tcp_sendpage,
1922 	.backlog_rcv		= tcp_v6_do_rcv,
1923 	.release_cb		= tcp_release_cb,
1924 	.mtu_reduced		= tcp_v6_mtu_reduced,
1925 	.hash			= tcp_v6_hash,
1926 	.unhash			= inet_unhash,
1927 	.get_port		= inet_csk_get_port,
1928 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1929 	.sockets_allocated	= &tcp_sockets_allocated,
1930 	.memory_allocated	= &tcp_memory_allocated,
1931 	.memory_pressure	= &tcp_memory_pressure,
1932 	.orphan_count		= &tcp_orphan_count,
1933 	.sysctl_wmem		= sysctl_tcp_wmem,
1934 	.sysctl_rmem		= sysctl_tcp_rmem,
1935 	.max_header		= MAX_TCP_HEADER,
1936 	.obj_size		= sizeof(struct tcp6_sock),
1937 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1938 	.twsk_prot		= &tcp6_timewait_sock_ops,
1939 	.rsk_prot		= &tcp6_request_sock_ops,
1940 	.h.hashinfo		= &tcp_hashinfo,
1941 	.no_autobind		= true,
1942 #ifdef CONFIG_COMPAT
1943 	.compat_setsockopt	= compat_tcp_setsockopt,
1944 	.compat_getsockopt	= compat_tcp_getsockopt,
1945 #endif
1946 #ifdef CONFIG_MEMCG_KMEM
1947 	.proto_cgroup		= tcp_proto_cgroup,
1948 #endif
1949 	.clear_sk		= tcp_v6_clear_sk,
1950 };
1951 
1952 static const struct inet6_protocol tcpv6_protocol = {
1953 	.early_demux	=	tcp_v6_early_demux,
1954 	.handler	=	tcp_v6_rcv,
1955 	.err_handler	=	tcp_v6_err,
1956 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1957 };
1958 
1959 static struct inet_protosw tcpv6_protosw = {
1960 	.type		=	SOCK_STREAM,
1961 	.protocol	=	IPPROTO_TCP,
1962 	.prot		=	&tcpv6_prot,
1963 	.ops		=	&inet6_stream_ops,
1964 	.no_check	=	0,
1965 	.flags		=	INET_PROTOSW_PERMANENT |
1966 				INET_PROTOSW_ICSK,
1967 };
1968 
1969 static int __net_init tcpv6_net_init(struct net *net)
1970 {
1971 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1972 				    SOCK_RAW, IPPROTO_TCP, net);
1973 }
1974 
1975 static void __net_exit tcpv6_net_exit(struct net *net)
1976 {
1977 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1978 }
1979 
1980 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1981 {
1982 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1983 }
1984 
1985 static struct pernet_operations tcpv6_net_ops = {
1986 	.init	    = tcpv6_net_init,
1987 	.exit	    = tcpv6_net_exit,
1988 	.exit_batch = tcpv6_net_exit_batch,
1989 };
1990 
1991 int __init tcpv6_init(void)
1992 {
1993 	int ret;
1994 
1995 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1996 	if (ret)
1997 		goto out;
1998 
1999 	/* register inet6 protocol */
2000 	ret = inet6_register_protosw(&tcpv6_protosw);
2001 	if (ret)
2002 		goto out_tcpv6_protocol;
2003 
2004 	ret = register_pernet_subsys(&tcpv6_net_ops);
2005 	if (ret)
2006 		goto out_tcpv6_protosw;
2007 out:
2008 	return ret;
2009 
2010 out_tcpv6_protosw:
2011 	inet6_unregister_protosw(&tcpv6_protosw);
2012 out_tcpv6_protocol:
2013 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2014 	goto out;
2015 }
2016 
2017 void tcpv6_exit(void)
2018 {
2019 	unregister_pernet_subsys(&tcpv6_net_ops);
2020 	inet6_unregister_protosw(&tcpv6_protosw);
2021 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2022 }
2023