1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	TCP over IPv6
4  *	Linux INET6 implementation
5  *
6  *	Authors:
7  *	Pedro Roque		<roque@di.fc.ul.pt>
8  *
9  *	Based on:
10  *	linux/net/ipv4/tcp.c
11  *	linux/net/ipv4/tcp_input.c
12  *	linux/net/ipv4/tcp_output.c
13  *
14  *	Fixes:
15  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
16  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
17  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
18  *					a single port at the same time.
19  *	YOSHIFUJI Hideaki @USAGI:	convert /proc/net/tcp6 to seq_file.
20  */
21 
22 #include <linux/bottom_half.h>
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/jiffies.h>
30 #include <linux/in.h>
31 #include <linux/in6.h>
32 #include <linux/netdevice.h>
33 #include <linux/init.h>
34 #include <linux/jhash.h>
35 #include <linux/ipsec.h>
36 #include <linux/times.h>
37 #include <linux/slab.h>
38 #include <linux/uaccess.h>
39 #include <linux/ipv6.h>
40 #include <linux/icmpv6.h>
41 #include <linux/random.h>
42 #include <linux/indirect_call_wrapper.h>
43 
44 #include <net/tcp.h>
45 #include <net/ndisc.h>
46 #include <net/inet6_hashtables.h>
47 #include <net/inet6_connection_sock.h>
48 #include <net/ipv6.h>
49 #include <net/transp_v6.h>
50 #include <net/addrconf.h>
51 #include <net/ip6_route.h>
52 #include <net/ip6_checksum.h>
53 #include <net/inet_ecn.h>
54 #include <net/protocol.h>
55 #include <net/xfrm.h>
56 #include <net/snmp.h>
57 #include <net/dsfield.h>
58 #include <net/timewait_sock.h>
59 #include <net/inet_common.h>
60 #include <net/secure_seq.h>
61 #include <net/busy_poll.h>
62 
63 #include <linux/proc_fs.h>
64 #include <linux/seq_file.h>
65 
66 #include <crypto/hash.h>
67 #include <linux/scatterlist.h>
68 
69 #include <trace/events/tcp.h>
70 
71 static void	tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
72 static void	tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
73 				      struct request_sock *req);
74 
75 INDIRECT_CALLABLE_SCOPE int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
76 
77 static const struct inet_connection_sock_af_ops ipv6_mapped;
78 const struct inet_connection_sock_af_ops ipv6_specific;
79 #ifdef CONFIG_TCP_MD5SIG
80 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
81 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
82 #else
tcp_v6_md5_do_lookup(const struct sock * sk,const struct in6_addr * addr,int l3index)83 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
84 						   const struct in6_addr *addr,
85 						   int l3index)
86 {
87 	return NULL;
88 }
89 #endif
90 
91 /* Helper returning the inet6 address from a given tcp socket.
92  * It can be used in TCP stack instead of inet6_sk(sk).
93  * This avoids a dereference and allow compiler optimizations.
94  * It is a specialized version of inet6_sk_generic().
95  */
tcp_inet6_sk(const struct sock * sk)96 static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk)
97 {
98 	unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo);
99 
100 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
101 }
102 
inet6_sk_rx_dst_set(struct sock * sk,const struct sk_buff * skb)103 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
104 {
105 	struct dst_entry *dst = skb_dst(skb);
106 
107 	if (dst && dst_hold_safe(dst)) {
108 		const struct rt6_info *rt = (const struct rt6_info *)dst;
109 
110 		rcu_assign_pointer(sk->sk_rx_dst, dst);
111 		sk->sk_rx_dst_ifindex = skb->skb_iif;
112 		sk->sk_rx_dst_cookie = rt6_get_cookie(rt);
113 	}
114 }
115 
tcp_v6_init_seq(const struct sk_buff * skb)116 static u32 tcp_v6_init_seq(const struct sk_buff *skb)
117 {
118 	return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32,
119 				ipv6_hdr(skb)->saddr.s6_addr32,
120 				tcp_hdr(skb)->dest,
121 				tcp_hdr(skb)->source);
122 }
123 
tcp_v6_init_ts_off(const struct net * net,const struct sk_buff * skb)124 static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb)
125 {
126 	return secure_tcpv6_ts_off(net, ipv6_hdr(skb)->daddr.s6_addr32,
127 				   ipv6_hdr(skb)->saddr.s6_addr32);
128 }
129 
tcp_v6_pre_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)130 static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
131 			      int addr_len)
132 {
133 	/* This check is replicated from tcp_v6_connect() and intended to
134 	 * prevent BPF program called below from accessing bytes that are out
135 	 * of the bound specified by user in addr_len.
136 	 */
137 	if (addr_len < SIN6_LEN_RFC2133)
138 		return -EINVAL;
139 
140 	sock_owned_by_me(sk);
141 
142 	return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr);
143 }
144 
tcp_v6_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)145 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
146 			  int addr_len)
147 {
148 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
149 	struct inet_connection_sock *icsk = inet_csk(sk);
150 	struct in6_addr *saddr = NULL, *final_p, final;
151 	struct inet_timewait_death_row *tcp_death_row;
152 	struct ipv6_pinfo *np = tcp_inet6_sk(sk);
153 	struct inet_sock *inet = inet_sk(sk);
154 	struct tcp_sock *tp = tcp_sk(sk);
155 	struct net *net = sock_net(sk);
156 	struct ipv6_txoptions *opt;
157 	struct dst_entry *dst;
158 	struct flowi6 fl6;
159 	int addr_type;
160 	int err;
161 
162 	if (addr_len < SIN6_LEN_RFC2133)
163 		return -EINVAL;
164 
165 	if (usin->sin6_family != AF_INET6)
166 		return -EAFNOSUPPORT;
167 
168 	memset(&fl6, 0, sizeof(fl6));
169 
170 	if (np->sndflow) {
171 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
172 		IP6_ECN_flow_init(fl6.flowlabel);
173 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
174 			struct ip6_flowlabel *flowlabel;
175 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
176 			if (IS_ERR(flowlabel))
177 				return -EINVAL;
178 			fl6_sock_release(flowlabel);
179 		}
180 	}
181 
182 	/*
183 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
184 	 */
185 
186 	if (ipv6_addr_any(&usin->sin6_addr)) {
187 		if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
188 			ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
189 					       &usin->sin6_addr);
190 		else
191 			usin->sin6_addr = in6addr_loopback;
192 	}
193 
194 	addr_type = ipv6_addr_type(&usin->sin6_addr);
195 
196 	if (addr_type & IPV6_ADDR_MULTICAST)
197 		return -ENETUNREACH;
198 
199 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
200 		if (addr_len >= sizeof(struct sockaddr_in6) &&
201 		    usin->sin6_scope_id) {
202 			/* If interface is set while binding, indices
203 			 * must coincide.
204 			 */
205 			if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id))
206 				return -EINVAL;
207 
208 			sk->sk_bound_dev_if = usin->sin6_scope_id;
209 		}
210 
211 		/* Connect to link-local address requires an interface */
212 		if (!sk->sk_bound_dev_if)
213 			return -EINVAL;
214 	}
215 
216 	if (tp->rx_opt.ts_recent_stamp &&
217 	    !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
218 		tp->rx_opt.ts_recent = 0;
219 		tp->rx_opt.ts_recent_stamp = 0;
220 		WRITE_ONCE(tp->write_seq, 0);
221 	}
222 
223 	sk->sk_v6_daddr = usin->sin6_addr;
224 	np->flow_label = fl6.flowlabel;
225 
226 	/*
227 	 *	TCP over IPv4
228 	 */
229 
230 	if (addr_type & IPV6_ADDR_MAPPED) {
231 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
232 		struct sockaddr_in sin;
233 
234 		if (ipv6_only_sock(sk))
235 			return -ENETUNREACH;
236 
237 		sin.sin_family = AF_INET;
238 		sin.sin_port = usin->sin6_port;
239 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
240 
241 		/* Paired with READ_ONCE() in tcp_(get|set)sockopt() */
242 		WRITE_ONCE(icsk->icsk_af_ops, &ipv6_mapped);
243 		if (sk_is_mptcp(sk))
244 			mptcpv6_handle_mapped(sk, true);
245 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
246 #ifdef CONFIG_TCP_MD5SIG
247 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
248 #endif
249 
250 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
251 
252 		if (err) {
253 			icsk->icsk_ext_hdr_len = exthdrlen;
254 			/* Paired with READ_ONCE() in tcp_(get|set)sockopt() */
255 			WRITE_ONCE(icsk->icsk_af_ops, &ipv6_specific);
256 			if (sk_is_mptcp(sk))
257 				mptcpv6_handle_mapped(sk, false);
258 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
259 #ifdef CONFIG_TCP_MD5SIG
260 			tp->af_specific = &tcp_sock_ipv6_specific;
261 #endif
262 			goto failure;
263 		}
264 		np->saddr = sk->sk_v6_rcv_saddr;
265 
266 		return err;
267 	}
268 
269 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
270 		saddr = &sk->sk_v6_rcv_saddr;
271 
272 	fl6.flowi6_proto = IPPROTO_TCP;
273 	fl6.daddr = sk->sk_v6_daddr;
274 	fl6.saddr = saddr ? *saddr : np->saddr;
275 	fl6.flowi6_oif = sk->sk_bound_dev_if;
276 	fl6.flowi6_mark = sk->sk_mark;
277 	fl6.fl6_dport = usin->sin6_port;
278 	fl6.fl6_sport = inet->inet_sport;
279 	fl6.flowi6_uid = sk->sk_uid;
280 
281 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
282 	final_p = fl6_update_dst(&fl6, opt, &final);
283 
284 	security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
285 
286 	dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p);
287 	if (IS_ERR(dst)) {
288 		err = PTR_ERR(dst);
289 		goto failure;
290 	}
291 
292 	tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
293 
294 	if (!saddr) {
295 		saddr = &fl6.saddr;
296 
297 		err = inet_bhash2_update_saddr(sk, saddr, AF_INET6);
298 		if (err)
299 			goto failure;
300 	}
301 
302 	/* set the source address */
303 	np->saddr = *saddr;
304 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
305 
306 	sk->sk_gso_type = SKB_GSO_TCPV6;
307 	ip6_dst_store(sk, dst, NULL, NULL);
308 
309 	icsk->icsk_ext_hdr_len = 0;
310 	if (opt)
311 		icsk->icsk_ext_hdr_len = opt->opt_flen +
312 					 opt->opt_nflen;
313 
314 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
315 
316 	inet->inet_dport = usin->sin6_port;
317 
318 	tcp_set_state(sk, TCP_SYN_SENT);
319 	err = inet6_hash_connect(tcp_death_row, sk);
320 	if (err)
321 		goto late_failure;
322 
323 	sk_set_txhash(sk);
324 
325 	if (likely(!tp->repair)) {
326 		if (!tp->write_seq)
327 			WRITE_ONCE(tp->write_seq,
328 				   secure_tcpv6_seq(np->saddr.s6_addr32,
329 						    sk->sk_v6_daddr.s6_addr32,
330 						    inet->inet_sport,
331 						    inet->inet_dport));
332 		tp->tsoffset = secure_tcpv6_ts_off(net, np->saddr.s6_addr32,
333 						   sk->sk_v6_daddr.s6_addr32);
334 	}
335 
336 	if (tcp_fastopen_defer_connect(sk, &err))
337 		return err;
338 	if (err)
339 		goto late_failure;
340 
341 	err = tcp_connect(sk);
342 	if (err)
343 		goto late_failure;
344 
345 	return 0;
346 
347 late_failure:
348 	tcp_set_state(sk, TCP_CLOSE);
349 	inet_bhash2_reset_saddr(sk);
350 failure:
351 	inet->inet_dport = 0;
352 	sk->sk_route_caps = 0;
353 	return err;
354 }
355 
tcp_v6_mtu_reduced(struct sock * sk)356 static void tcp_v6_mtu_reduced(struct sock *sk)
357 {
358 	struct dst_entry *dst;
359 	u32 mtu;
360 
361 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
362 		return;
363 
364 	mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
365 
366 	/* Drop requests trying to increase our current mss.
367 	 * Check done in __ip6_rt_update_pmtu() is too late.
368 	 */
369 	if (tcp_mtu_to_mss(sk, mtu) >= tcp_sk(sk)->mss_cache)
370 		return;
371 
372 	dst = inet6_csk_update_pmtu(sk, mtu);
373 	if (!dst)
374 		return;
375 
376 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
377 		tcp_sync_mss(sk, dst_mtu(dst));
378 		tcp_simple_retransmit(sk);
379 	}
380 }
381 
tcp_v6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)382 static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
383 		u8 type, u8 code, int offset, __be32 info)
384 {
385 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
386 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
387 	struct net *net = dev_net(skb->dev);
388 	struct request_sock *fastopen;
389 	struct ipv6_pinfo *np;
390 	struct tcp_sock *tp;
391 	__u32 seq, snd_una;
392 	struct sock *sk;
393 	bool fatal;
394 	int err;
395 
396 	sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
397 					&hdr->daddr, th->dest,
398 					&hdr->saddr, ntohs(th->source),
399 					skb->dev->ifindex, inet6_sdif(skb));
400 
401 	if (!sk) {
402 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
403 				  ICMP6_MIB_INERRORS);
404 		return -ENOENT;
405 	}
406 
407 	if (sk->sk_state == TCP_TIME_WAIT) {
408 		inet_twsk_put(inet_twsk(sk));
409 		return 0;
410 	}
411 	seq = ntohl(th->seq);
412 	fatal = icmpv6_err_convert(type, code, &err);
413 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
414 		tcp_req_err(sk, seq, fatal);
415 		return 0;
416 	}
417 
418 	bh_lock_sock(sk);
419 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
420 		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
421 
422 	if (sk->sk_state == TCP_CLOSE)
423 		goto out;
424 
425 	if (static_branch_unlikely(&ip6_min_hopcount)) {
426 		/* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
427 		if (ipv6_hdr(skb)->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) {
428 			__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
429 			goto out;
430 		}
431 	}
432 
433 	tp = tcp_sk(sk);
434 	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
435 	fastopen = rcu_dereference(tp->fastopen_rsk);
436 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
437 	if (sk->sk_state != TCP_LISTEN &&
438 	    !between(seq, snd_una, tp->snd_nxt)) {
439 		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
440 		goto out;
441 	}
442 
443 	np = tcp_inet6_sk(sk);
444 
445 	if (type == NDISC_REDIRECT) {
446 		if (!sock_owned_by_user(sk)) {
447 			struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
448 
449 			if (dst)
450 				dst->ops->redirect(dst, sk, skb);
451 		}
452 		goto out;
453 	}
454 
455 	if (type == ICMPV6_PKT_TOOBIG) {
456 		u32 mtu = ntohl(info);
457 
458 		/* We are not interested in TCP_LISTEN and open_requests
459 		 * (SYN-ACKs send out by Linux are always <576bytes so
460 		 * they should go through unfragmented).
461 		 */
462 		if (sk->sk_state == TCP_LISTEN)
463 			goto out;
464 
465 		if (!ip6_sk_accept_pmtu(sk))
466 			goto out;
467 
468 		if (mtu < IPV6_MIN_MTU)
469 			goto out;
470 
471 		WRITE_ONCE(tp->mtu_info, mtu);
472 
473 		if (!sock_owned_by_user(sk))
474 			tcp_v6_mtu_reduced(sk);
475 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
476 					   &sk->sk_tsq_flags))
477 			sock_hold(sk);
478 		goto out;
479 	}
480 
481 
482 	/* Might be for an request_sock */
483 	switch (sk->sk_state) {
484 	case TCP_SYN_SENT:
485 	case TCP_SYN_RECV:
486 		/* Only in fast or simultaneous open. If a fast open socket is
487 		 * already accepted it is treated as a connected one below.
488 		 */
489 		if (fastopen && !fastopen->sk)
490 			break;
491 
492 		ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th);
493 
494 		if (!sock_owned_by_user(sk)) {
495 			sk->sk_err = err;
496 			sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
497 
498 			tcp_done(sk);
499 		} else
500 			sk->sk_err_soft = err;
501 		goto out;
502 	case TCP_LISTEN:
503 		break;
504 	default:
505 		/* check if this ICMP message allows revert of backoff.
506 		 * (see RFC 6069)
507 		 */
508 		if (!fastopen && type == ICMPV6_DEST_UNREACH &&
509 		    code == ICMPV6_NOROUTE)
510 			tcp_ld_RTO_revert(sk, seq);
511 	}
512 
513 	if (!sock_owned_by_user(sk) && np->recverr) {
514 		sk->sk_err = err;
515 		sk_error_report(sk);
516 	} else
517 		sk->sk_err_soft = err;
518 
519 out:
520 	bh_unlock_sock(sk);
521 	sock_put(sk);
522 	return 0;
523 }
524 
525 
tcp_v6_send_synack(const struct sock * sk,struct dst_entry * dst,struct flowi * fl,struct request_sock * req,struct tcp_fastopen_cookie * foc,enum tcp_synack_type synack_type,struct sk_buff * syn_skb)526 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
527 			      struct flowi *fl,
528 			      struct request_sock *req,
529 			      struct tcp_fastopen_cookie *foc,
530 			      enum tcp_synack_type synack_type,
531 			      struct sk_buff *syn_skb)
532 {
533 	struct inet_request_sock *ireq = inet_rsk(req);
534 	struct ipv6_pinfo *np = tcp_inet6_sk(sk);
535 	struct ipv6_txoptions *opt;
536 	struct flowi6 *fl6 = &fl->u.ip6;
537 	struct sk_buff *skb;
538 	int err = -ENOMEM;
539 	u8 tclass;
540 
541 	/* First, grab a route. */
542 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
543 					       IPPROTO_TCP)) == NULL)
544 		goto done;
545 
546 	skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
547 
548 	if (skb) {
549 		__tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
550 				    &ireq->ir_v6_rmt_addr);
551 
552 		fl6->daddr = ireq->ir_v6_rmt_addr;
553 		if (np->repflow && ireq->pktopts)
554 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
555 
556 		tclass = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
557 				(tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
558 				(np->tclass & INET_ECN_MASK) :
559 				np->tclass;
560 
561 		if (!INET_ECN_is_capable(tclass) &&
562 		    tcp_bpf_ca_needs_ecn((struct sock *)req))
563 			tclass |= INET_ECN_ECT_0;
564 
565 		rcu_read_lock();
566 		opt = ireq->ipv6_opt;
567 		if (!opt)
568 			opt = rcu_dereference(np->opt);
569 		err = ip6_xmit(sk, skb, fl6, skb->mark ? : sk->sk_mark, opt,
570 			       tclass, sk->sk_priority);
571 		rcu_read_unlock();
572 		err = net_xmit_eval(err);
573 	}
574 
575 done:
576 	return err;
577 }
578 
579 
tcp_v6_reqsk_destructor(struct request_sock * req)580 static void tcp_v6_reqsk_destructor(struct request_sock *req)
581 {
582 	kfree(inet_rsk(req)->ipv6_opt);
583 	consume_skb(inet_rsk(req)->pktopts);
584 }
585 
586 #ifdef CONFIG_TCP_MD5SIG
tcp_v6_md5_do_lookup(const struct sock * sk,const struct in6_addr * addr,int l3index)587 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
588 						   const struct in6_addr *addr,
589 						   int l3index)
590 {
591 	return tcp_md5_do_lookup(sk, l3index,
592 				 (union tcp_md5_addr *)addr, AF_INET6);
593 }
594 
tcp_v6_md5_lookup(const struct sock * sk,const struct sock * addr_sk)595 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
596 						const struct sock *addr_sk)
597 {
598 	int l3index;
599 
600 	l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
601 						 addr_sk->sk_bound_dev_if);
602 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr,
603 				    l3index);
604 }
605 
tcp_v6_parse_md5_keys(struct sock * sk,int optname,sockptr_t optval,int optlen)606 static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
607 				 sockptr_t optval, int optlen)
608 {
609 	struct tcp_md5sig cmd;
610 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
611 	int l3index = 0;
612 	u8 prefixlen;
613 	u8 flags;
614 
615 	if (optlen < sizeof(cmd))
616 		return -EINVAL;
617 
618 	if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
619 		return -EFAULT;
620 
621 	if (sin6->sin6_family != AF_INET6)
622 		return -EINVAL;
623 
624 	flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
625 
626 	if (optname == TCP_MD5SIG_EXT &&
627 	    cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
628 		prefixlen = cmd.tcpm_prefixlen;
629 		if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) &&
630 					prefixlen > 32))
631 			return -EINVAL;
632 	} else {
633 		prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128;
634 	}
635 
636 	if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
637 	    cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
638 		struct net_device *dev;
639 
640 		rcu_read_lock();
641 		dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
642 		if (dev && netif_is_l3_master(dev))
643 			l3index = dev->ifindex;
644 		rcu_read_unlock();
645 
646 		/* ok to reference set/not set outside of rcu;
647 		 * right now device MUST be an L3 master
648 		 */
649 		if (!dev || !l3index)
650 			return -EINVAL;
651 	}
652 
653 	if (!cmd.tcpm_keylen) {
654 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
655 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
656 					      AF_INET, prefixlen,
657 					      l3index, flags);
658 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
659 				      AF_INET6, prefixlen, l3index, flags);
660 	}
661 
662 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
663 		return -EINVAL;
664 
665 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
666 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
667 				      AF_INET, prefixlen, l3index, flags,
668 				      cmd.tcpm_key, cmd.tcpm_keylen,
669 				      GFP_KERNEL);
670 
671 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
672 			      AF_INET6, prefixlen, l3index, flags,
673 			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
674 }
675 
tcp_v6_md5_hash_headers(struct tcp_md5sig_pool * hp,const struct in6_addr * daddr,const struct in6_addr * saddr,const struct tcphdr * th,int nbytes)676 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
677 				   const struct in6_addr *daddr,
678 				   const struct in6_addr *saddr,
679 				   const struct tcphdr *th, int nbytes)
680 {
681 	struct tcp6_pseudohdr *bp;
682 	struct scatterlist sg;
683 	struct tcphdr *_th;
684 
685 	bp = hp->scratch;
686 	/* 1. TCP pseudo-header (RFC2460) */
687 	bp->saddr = *saddr;
688 	bp->daddr = *daddr;
689 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
690 	bp->len = cpu_to_be32(nbytes);
691 
692 	_th = (struct tcphdr *)(bp + 1);
693 	memcpy(_th, th, sizeof(*th));
694 	_th->check = 0;
695 
696 	sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
697 	ahash_request_set_crypt(hp->md5_req, &sg, NULL,
698 				sizeof(*bp) + sizeof(*th));
699 	return crypto_ahash_update(hp->md5_req);
700 }
701 
tcp_v6_md5_hash_hdr(char * md5_hash,const struct tcp_md5sig_key * key,const struct in6_addr * daddr,struct in6_addr * saddr,const struct tcphdr * th)702 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
703 			       const struct in6_addr *daddr, struct in6_addr *saddr,
704 			       const struct tcphdr *th)
705 {
706 	struct tcp_md5sig_pool *hp;
707 	struct ahash_request *req;
708 
709 	hp = tcp_get_md5sig_pool();
710 	if (!hp)
711 		goto clear_hash_noput;
712 	req = hp->md5_req;
713 
714 	if (crypto_ahash_init(req))
715 		goto clear_hash;
716 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
717 		goto clear_hash;
718 	if (tcp_md5_hash_key(hp, key))
719 		goto clear_hash;
720 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
721 	if (crypto_ahash_final(req))
722 		goto clear_hash;
723 
724 	tcp_put_md5sig_pool();
725 	return 0;
726 
727 clear_hash:
728 	tcp_put_md5sig_pool();
729 clear_hash_noput:
730 	memset(md5_hash, 0, 16);
731 	return 1;
732 }
733 
tcp_v6_md5_hash_skb(char * md5_hash,const struct tcp_md5sig_key * key,const struct sock * sk,const struct sk_buff * skb)734 static int tcp_v6_md5_hash_skb(char *md5_hash,
735 			       const struct tcp_md5sig_key *key,
736 			       const struct sock *sk,
737 			       const struct sk_buff *skb)
738 {
739 	const struct in6_addr *saddr, *daddr;
740 	struct tcp_md5sig_pool *hp;
741 	struct ahash_request *req;
742 	const struct tcphdr *th = tcp_hdr(skb);
743 
744 	if (sk) { /* valid for establish/request sockets */
745 		saddr = &sk->sk_v6_rcv_saddr;
746 		daddr = &sk->sk_v6_daddr;
747 	} else {
748 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
749 		saddr = &ip6h->saddr;
750 		daddr = &ip6h->daddr;
751 	}
752 
753 	hp = tcp_get_md5sig_pool();
754 	if (!hp)
755 		goto clear_hash_noput;
756 	req = hp->md5_req;
757 
758 	if (crypto_ahash_init(req))
759 		goto clear_hash;
760 
761 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
762 		goto clear_hash;
763 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
764 		goto clear_hash;
765 	if (tcp_md5_hash_key(hp, key))
766 		goto clear_hash;
767 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
768 	if (crypto_ahash_final(req))
769 		goto clear_hash;
770 
771 	tcp_put_md5sig_pool();
772 	return 0;
773 
774 clear_hash:
775 	tcp_put_md5sig_pool();
776 clear_hash_noput:
777 	memset(md5_hash, 0, 16);
778 	return 1;
779 }
780 
781 #endif
782 
tcp_v6_init_req(struct request_sock * req,const struct sock * sk_listener,struct sk_buff * skb)783 static void tcp_v6_init_req(struct request_sock *req,
784 			    const struct sock *sk_listener,
785 			    struct sk_buff *skb)
786 {
787 	bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
788 	struct inet_request_sock *ireq = inet_rsk(req);
789 	const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener);
790 
791 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
792 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
793 
794 	/* So that link locals have meaning */
795 	if ((!sk_listener->sk_bound_dev_if || l3_slave) &&
796 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
797 		ireq->ir_iif = tcp_v6_iif(skb);
798 
799 	if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
800 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
801 	     np->rxopt.bits.rxinfo ||
802 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
803 	     np->rxopt.bits.rxohlim || np->repflow)) {
804 		refcount_inc(&skb->users);
805 		ireq->pktopts = skb;
806 	}
807 }
808 
tcp_v6_route_req(const struct sock * sk,struct sk_buff * skb,struct flowi * fl,struct request_sock * req)809 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
810 					  struct sk_buff *skb,
811 					  struct flowi *fl,
812 					  struct request_sock *req)
813 {
814 	tcp_v6_init_req(req, sk, skb);
815 
816 	if (security_inet_conn_request(sk, skb, req))
817 		return NULL;
818 
819 	return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
820 }
821 
822 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
823 	.family		=	AF_INET6,
824 	.obj_size	=	sizeof(struct tcp6_request_sock),
825 	.rtx_syn_ack	=	tcp_rtx_synack,
826 	.send_ack	=	tcp_v6_reqsk_send_ack,
827 	.destructor	=	tcp_v6_reqsk_destructor,
828 	.send_reset	=	tcp_v6_send_reset,
829 	.syn_ack_timeout =	tcp_syn_ack_timeout,
830 };
831 
832 const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
833 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
834 				sizeof(struct ipv6hdr),
835 #ifdef CONFIG_TCP_MD5SIG
836 	.req_md5_lookup	=	tcp_v6_md5_lookup,
837 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
838 #endif
839 #ifdef CONFIG_SYN_COOKIES
840 	.cookie_init_seq =	cookie_v6_init_sequence,
841 #endif
842 	.route_req	=	tcp_v6_route_req,
843 	.init_seq	=	tcp_v6_init_seq,
844 	.init_ts_off	=	tcp_v6_init_ts_off,
845 	.send_synack	=	tcp_v6_send_synack,
846 };
847 
tcp_v6_send_response(const struct sock * sk,struct sk_buff * skb,u32 seq,u32 ack,u32 win,u32 tsval,u32 tsecr,int oif,struct tcp_md5sig_key * key,int rst,u8 tclass,__be32 label,u32 priority,u32 txhash)848 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
849 				 u32 ack, u32 win, u32 tsval, u32 tsecr,
850 				 int oif, struct tcp_md5sig_key *key, int rst,
851 				 u8 tclass, __be32 label, u32 priority, u32 txhash)
852 {
853 	const struct tcphdr *th = tcp_hdr(skb);
854 	struct tcphdr *t1;
855 	struct sk_buff *buff;
856 	struct flowi6 fl6;
857 	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
858 	struct sock *ctl_sk = net->ipv6.tcp_sk;
859 	unsigned int tot_len = sizeof(struct tcphdr);
860 	__be32 mrst = 0, *topt;
861 	struct dst_entry *dst;
862 	__u32 mark = 0;
863 
864 	if (tsecr)
865 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
866 #ifdef CONFIG_TCP_MD5SIG
867 	if (key)
868 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
869 #endif
870 
871 #ifdef CONFIG_MPTCP
872 	if (rst && !key) {
873 		mrst = mptcp_reset_option(skb);
874 
875 		if (mrst)
876 			tot_len += sizeof(__be32);
877 	}
878 #endif
879 
880 	buff = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC);
881 	if (!buff)
882 		return;
883 
884 	skb_reserve(buff, MAX_TCP_HEADER);
885 
886 	t1 = skb_push(buff, tot_len);
887 	skb_reset_transport_header(buff);
888 
889 	/* Swap the send and the receive. */
890 	memset(t1, 0, sizeof(*t1));
891 	t1->dest = th->source;
892 	t1->source = th->dest;
893 	t1->doff = tot_len / 4;
894 	t1->seq = htonl(seq);
895 	t1->ack_seq = htonl(ack);
896 	t1->ack = !rst || !th->ack;
897 	t1->rst = rst;
898 	t1->window = htons(win);
899 
900 	topt = (__be32 *)(t1 + 1);
901 
902 	if (tsecr) {
903 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
904 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
905 		*topt++ = htonl(tsval);
906 		*topt++ = htonl(tsecr);
907 	}
908 
909 	if (mrst)
910 		*topt++ = mrst;
911 
912 #ifdef CONFIG_TCP_MD5SIG
913 	if (key) {
914 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
915 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
916 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
917 				    &ipv6_hdr(skb)->saddr,
918 				    &ipv6_hdr(skb)->daddr, t1);
919 	}
920 #endif
921 
922 	memset(&fl6, 0, sizeof(fl6));
923 	fl6.daddr = ipv6_hdr(skb)->saddr;
924 	fl6.saddr = ipv6_hdr(skb)->daddr;
925 	fl6.flowlabel = label;
926 
927 	buff->ip_summed = CHECKSUM_PARTIAL;
928 
929 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
930 
931 	fl6.flowi6_proto = IPPROTO_TCP;
932 	if (rt6_need_strict(&fl6.daddr) && !oif)
933 		fl6.flowi6_oif = tcp_v6_iif(skb);
934 	else {
935 		if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
936 			oif = skb->skb_iif;
937 
938 		fl6.flowi6_oif = oif;
939 	}
940 
941 	if (sk) {
942 		if (sk->sk_state == TCP_TIME_WAIT)
943 			mark = inet_twsk(sk)->tw_mark;
944 		else
945 			mark = sk->sk_mark;
946 		skb_set_delivery_time(buff, tcp_transmit_time(sk), true);
947 	}
948 	if (txhash) {
949 		/* autoflowlabel/skb_get_hash_flowi6 rely on buff->hash */
950 		skb_set_hash(buff, txhash, PKT_HASH_TYPE_L4);
951 	}
952 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;
953 	fl6.fl6_dport = t1->dest;
954 	fl6.fl6_sport = t1->source;
955 	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
956 	security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
957 
958 	/* Pass a socket to ip6_dst_lookup either it is for RST
959 	 * Underlying function will use this to retrieve the network
960 	 * namespace
961 	 */
962 	if (sk && sk->sk_state != TCP_TIME_WAIT)
963 		dst = ip6_dst_lookup_flow(net, sk, &fl6, NULL); /*sk's xfrm_policy can be referred*/
964 	else
965 		dst = ip6_dst_lookup_flow(net, ctl_sk, &fl6, NULL);
966 	if (!IS_ERR(dst)) {
967 		skb_dst_set(buff, dst);
968 		ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL,
969 			 tclass & ~INET_ECN_MASK, priority);
970 		TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
971 		if (rst)
972 			TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
973 		return;
974 	}
975 
976 	kfree_skb(buff);
977 }
978 
tcp_v6_send_reset(const struct sock * sk,struct sk_buff * skb)979 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
980 {
981 	const struct tcphdr *th = tcp_hdr(skb);
982 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
983 	u32 seq = 0, ack_seq = 0;
984 	struct tcp_md5sig_key *key = NULL;
985 #ifdef CONFIG_TCP_MD5SIG
986 	const __u8 *hash_location = NULL;
987 	unsigned char newhash[16];
988 	int genhash;
989 	struct sock *sk1 = NULL;
990 #endif
991 	__be32 label = 0;
992 	u32 priority = 0;
993 	struct net *net;
994 	u32 txhash = 0;
995 	int oif = 0;
996 
997 	if (th->rst)
998 		return;
999 
1000 	/* If sk not NULL, it means we did a successful lookup and incoming
1001 	 * route had to be correct. prequeue might have dropped our dst.
1002 	 */
1003 	if (!sk && !ipv6_unicast_destination(skb))
1004 		return;
1005 
1006 	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
1007 #ifdef CONFIG_TCP_MD5SIG
1008 	rcu_read_lock();
1009 	hash_location = tcp_parse_md5sig_option(th);
1010 	if (sk && sk_fullsock(sk)) {
1011 		int l3index;
1012 
1013 		/* sdif set, means packet ingressed via a device
1014 		 * in an L3 domain and inet_iif is set to it.
1015 		 */
1016 		l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1017 		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
1018 	} else if (hash_location) {
1019 		int dif = tcp_v6_iif_l3_slave(skb);
1020 		int sdif = tcp_v6_sdif(skb);
1021 		int l3index;
1022 
1023 		/*
1024 		 * active side is lost. Try to find listening socket through
1025 		 * source port, and then find md5 key through listening socket.
1026 		 * we are not loose security here:
1027 		 * Incoming packet is checked with md5 hash with finding key,
1028 		 * no RST generated if md5 hash doesn't match.
1029 		 */
1030 		sk1 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
1031 					    NULL, 0, &ipv6h->saddr, th->source,
1032 					    &ipv6h->daddr, ntohs(th->source),
1033 					    dif, sdif);
1034 		if (!sk1)
1035 			goto out;
1036 
1037 		/* sdif set, means packet ingressed via a device
1038 		 * in an L3 domain and dif is set to it.
1039 		 */
1040 		l3index = tcp_v6_sdif(skb) ? dif : 0;
1041 
1042 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
1043 		if (!key)
1044 			goto out;
1045 
1046 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
1047 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
1048 			goto out;
1049 	}
1050 #endif
1051 
1052 	if (th->ack)
1053 		seq = ntohl(th->ack_seq);
1054 	else
1055 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1056 			  (th->doff << 2);
1057 
1058 	if (sk) {
1059 		oif = sk->sk_bound_dev_if;
1060 		if (sk_fullsock(sk)) {
1061 			const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1062 
1063 			trace_tcp_send_reset(sk, skb);
1064 			if (np->repflow)
1065 				label = ip6_flowlabel(ipv6h);
1066 			priority = sk->sk_priority;
1067 			txhash = sk->sk_hash;
1068 		}
1069 		if (sk->sk_state == TCP_TIME_WAIT) {
1070 			label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel);
1071 			priority = inet_twsk(sk)->tw_priority;
1072 			txhash = inet_twsk(sk)->tw_txhash;
1073 		}
1074 	} else {
1075 		if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
1076 			label = ip6_flowlabel(ipv6h);
1077 	}
1078 
1079 	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1,
1080 			     ipv6_get_dsfield(ipv6h), label, priority, txhash);
1081 
1082 #ifdef CONFIG_TCP_MD5SIG
1083 out:
1084 	rcu_read_unlock();
1085 #endif
1086 }
1087 
tcp_v6_send_ack(const struct sock * sk,struct sk_buff * skb,u32 seq,u32 ack,u32 win,u32 tsval,u32 tsecr,int oif,struct tcp_md5sig_key * key,u8 tclass,__be32 label,u32 priority,u32 txhash)1088 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
1089 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
1090 			    struct tcp_md5sig_key *key, u8 tclass,
1091 			    __be32 label, u32 priority, u32 txhash)
1092 {
1093 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
1094 			     tclass, label, priority, txhash);
1095 }
1096 
tcp_v6_timewait_ack(struct sock * sk,struct sk_buff * skb)1097 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1098 {
1099 	struct inet_timewait_sock *tw = inet_twsk(sk);
1100 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1101 
1102 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1103 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1104 			tcp_time_stamp_raw() + tcptw->tw_ts_offset,
1105 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
1106 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
1107 			tw->tw_txhash);
1108 
1109 	inet_twsk_put(tw);
1110 }
1111 
tcp_v6_reqsk_send_ack(const struct sock * sk,struct sk_buff * skb,struct request_sock * req)1112 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1113 				  struct request_sock *req)
1114 {
1115 	int l3index;
1116 
1117 	l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1118 
1119 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1120 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1121 	 */
1122 	/* RFC 7323 2.3
1123 	 * The window field (SEG.WND) of every outgoing segment, with the
1124 	 * exception of <SYN> segments, MUST be right-shifted by
1125 	 * Rcv.Wind.Shift bits:
1126 	 */
1127 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
1128 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
1129 			tcp_rsk(req)->rcv_nxt,
1130 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1131 			tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
1132 			req->ts_recent, sk->sk_bound_dev_if,
1133 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index),
1134 			ipv6_get_dsfield(ipv6_hdr(skb)), 0, sk->sk_priority,
1135 			tcp_rsk(req)->txhash);
1136 }
1137 
1138 
tcp_v6_cookie_check(struct sock * sk,struct sk_buff * skb)1139 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
1140 {
1141 #ifdef CONFIG_SYN_COOKIES
1142 	const struct tcphdr *th = tcp_hdr(skb);
1143 
1144 	if (!th->syn)
1145 		sk = cookie_v6_check(sk, skb);
1146 #endif
1147 	return sk;
1148 }
1149 
tcp_v6_get_syncookie(struct sock * sk,struct ipv6hdr * iph,struct tcphdr * th,u32 * cookie)1150 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
1151 			 struct tcphdr *th, u32 *cookie)
1152 {
1153 	u16 mss = 0;
1154 #ifdef CONFIG_SYN_COOKIES
1155 	mss = tcp_get_syncookie_mss(&tcp6_request_sock_ops,
1156 				    &tcp_request_sock_ipv6_ops, sk, th);
1157 	if (mss) {
1158 		*cookie = __cookie_v6_init_sequence(iph, th, &mss);
1159 		tcp_synq_overflow(sk);
1160 	}
1161 #endif
1162 	return mss;
1163 }
1164 
tcp_v6_conn_request(struct sock * sk,struct sk_buff * skb)1165 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1166 {
1167 	if (skb->protocol == htons(ETH_P_IP))
1168 		return tcp_v4_conn_request(sk, skb);
1169 
1170 	if (!ipv6_unicast_destination(skb))
1171 		goto drop;
1172 
1173 	if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
1174 		__IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
1175 		return 0;
1176 	}
1177 
1178 	return tcp_conn_request(&tcp6_request_sock_ops,
1179 				&tcp_request_sock_ipv6_ops, sk, skb);
1180 
1181 drop:
1182 	tcp_listendrop(sk);
1183 	return 0; /* don't send reset */
1184 }
1185 
tcp_v6_restore_cb(struct sk_buff * skb)1186 static void tcp_v6_restore_cb(struct sk_buff *skb)
1187 {
1188 	/* We need to move header back to the beginning if xfrm6_policy_check()
1189 	 * and tcp_v6_fill_cb() are going to be called again.
1190 	 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1191 	 */
1192 	memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1193 		sizeof(struct inet6_skb_parm));
1194 }
1195 
tcp_v6_syn_recv_sock(const struct sock * sk,struct sk_buff * skb,struct request_sock * req,struct dst_entry * dst,struct request_sock * req_unhash,bool * own_req)1196 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1197 					 struct request_sock *req,
1198 					 struct dst_entry *dst,
1199 					 struct request_sock *req_unhash,
1200 					 bool *own_req)
1201 {
1202 	struct inet_request_sock *ireq;
1203 	struct ipv6_pinfo *newnp;
1204 	const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1205 	struct ipv6_txoptions *opt;
1206 	struct inet_sock *newinet;
1207 	bool found_dup_sk = false;
1208 	struct tcp_sock *newtp;
1209 	struct sock *newsk;
1210 #ifdef CONFIG_TCP_MD5SIG
1211 	struct tcp_md5sig_key *key;
1212 	int l3index;
1213 #endif
1214 	struct flowi6 fl6;
1215 
1216 	if (skb->protocol == htons(ETH_P_IP)) {
1217 		/*
1218 		 *	v6 mapped
1219 		 */
1220 
1221 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1222 					     req_unhash, own_req);
1223 
1224 		if (!newsk)
1225 			return NULL;
1226 
1227 		inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1228 
1229 		newnp = tcp_inet6_sk(newsk);
1230 		newtp = tcp_sk(newsk);
1231 
1232 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1233 
1234 		newnp->saddr = newsk->sk_v6_rcv_saddr;
1235 
1236 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1237 		if (sk_is_mptcp(newsk))
1238 			mptcpv6_handle_mapped(newsk, true);
1239 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1240 #ifdef CONFIG_TCP_MD5SIG
1241 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1242 #endif
1243 
1244 		newnp->ipv6_mc_list = NULL;
1245 		newnp->ipv6_ac_list = NULL;
1246 		newnp->ipv6_fl_list = NULL;
1247 		newnp->pktoptions  = NULL;
1248 		newnp->opt	   = NULL;
1249 		newnp->mcast_oif   = inet_iif(skb);
1250 		newnp->mcast_hops  = ip_hdr(skb)->ttl;
1251 		newnp->rcv_flowinfo = 0;
1252 		if (np->repflow)
1253 			newnp->flow_label = 0;
1254 
1255 		/*
1256 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1257 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1258 		 * that function for the gory details. -acme
1259 		 */
1260 
1261 		/* It is tricky place. Until this moment IPv4 tcp
1262 		   worked with IPv6 icsk.icsk_af_ops.
1263 		   Sync it now.
1264 		 */
1265 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1266 
1267 		return newsk;
1268 	}
1269 
1270 	ireq = inet_rsk(req);
1271 
1272 	if (sk_acceptq_is_full(sk))
1273 		goto out_overflow;
1274 
1275 	if (!dst) {
1276 		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1277 		if (!dst)
1278 			goto out;
1279 	}
1280 
1281 	newsk = tcp_create_openreq_child(sk, req, skb);
1282 	if (!newsk)
1283 		goto out_nonewsk;
1284 
1285 	/*
1286 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1287 	 * count here, tcp_create_openreq_child now does this for us, see the
1288 	 * comment in that function for the gory details. -acme
1289 	 */
1290 
1291 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1292 	ip6_dst_store(newsk, dst, NULL, NULL);
1293 	inet6_sk_rx_dst_set(newsk, skb);
1294 
1295 	inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1296 
1297 	newtp = tcp_sk(newsk);
1298 	newinet = inet_sk(newsk);
1299 	newnp = tcp_inet6_sk(newsk);
1300 
1301 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1302 
1303 	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1304 	newnp->saddr = ireq->ir_v6_loc_addr;
1305 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1306 	newsk->sk_bound_dev_if = ireq->ir_iif;
1307 
1308 	/* Now IPv6 options...
1309 
1310 	   First: no IPv4 options.
1311 	 */
1312 	newinet->inet_opt = NULL;
1313 	newnp->ipv6_mc_list = NULL;
1314 	newnp->ipv6_ac_list = NULL;
1315 	newnp->ipv6_fl_list = NULL;
1316 
1317 	/* Clone RX bits */
1318 	newnp->rxopt.all = np->rxopt.all;
1319 
1320 	newnp->pktoptions = NULL;
1321 	newnp->opt	  = NULL;
1322 	newnp->mcast_oif  = tcp_v6_iif(skb);
1323 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1324 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1325 	if (np->repflow)
1326 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1327 
1328 	/* Set ToS of the new socket based upon the value of incoming SYN.
1329 	 * ECT bits are set later in tcp_init_transfer().
1330 	 */
1331 	if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1332 		newnp->tclass = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1333 
1334 	/* Clone native IPv6 options from listening socket (if any)
1335 
1336 	   Yes, keeping reference count would be much more clever,
1337 	   but we make one more one thing there: reattach optmem
1338 	   to newsk.
1339 	 */
1340 	opt = ireq->ipv6_opt;
1341 	if (!opt)
1342 		opt = rcu_dereference(np->opt);
1343 	if (opt) {
1344 		opt = ipv6_dup_options(newsk, opt);
1345 		RCU_INIT_POINTER(newnp->opt, opt);
1346 	}
1347 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1348 	if (opt)
1349 		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1350 						    opt->opt_flen;
1351 
1352 	tcp_ca_openreq_child(newsk, dst);
1353 
1354 	tcp_sync_mss(newsk, dst_mtu(dst));
1355 	newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1356 
1357 	tcp_initialize_rcv_mss(newsk);
1358 
1359 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1360 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1361 
1362 #ifdef CONFIG_TCP_MD5SIG
1363 	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1364 
1365 	/* Copy over the MD5 key from the original socket */
1366 	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr, l3index);
1367 	if (key) {
1368 		/* We're using one, so create a matching key
1369 		 * on the newsk structure. If we fail to get
1370 		 * memory, then we end up not copying the key
1371 		 * across. Shucks.
1372 		 */
1373 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1374 			       AF_INET6, 128, l3index, key->flags, key->key, key->keylen,
1375 			       sk_gfp_mask(sk, GFP_ATOMIC));
1376 	}
1377 #endif
1378 
1379 	if (__inet_inherit_port(sk, newsk) < 0) {
1380 		inet_csk_prepare_forced_close(newsk);
1381 		tcp_done(newsk);
1382 		goto out;
1383 	}
1384 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1385 				       &found_dup_sk);
1386 	if (*own_req) {
1387 		tcp_move_syn(newtp, req);
1388 
1389 		/* Clone pktoptions received with SYN, if we own the req */
1390 		if (ireq->pktopts) {
1391 			newnp->pktoptions = skb_clone(ireq->pktopts,
1392 						      sk_gfp_mask(sk, GFP_ATOMIC));
1393 			consume_skb(ireq->pktopts);
1394 			ireq->pktopts = NULL;
1395 			if (newnp->pktoptions) {
1396 				tcp_v6_restore_cb(newnp->pktoptions);
1397 				skb_set_owner_r(newnp->pktoptions, newsk);
1398 			}
1399 		}
1400 	} else {
1401 		if (!req_unhash && found_dup_sk) {
1402 			/* This code path should only be executed in the
1403 			 * syncookie case only
1404 			 */
1405 			bh_unlock_sock(newsk);
1406 			sock_put(newsk);
1407 			newsk = NULL;
1408 		}
1409 	}
1410 
1411 	return newsk;
1412 
1413 out_overflow:
1414 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1415 out_nonewsk:
1416 	dst_release(dst);
1417 out:
1418 	tcp_listendrop(sk);
1419 	return NULL;
1420 }
1421 
1422 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1423 							   u32));
1424 /* The socket must have it's spinlock held when we get
1425  * here, unless it is a TCP_LISTEN socket.
1426  *
1427  * We have a potential double-lock case here, so even when
1428  * doing backlog processing we use the BH locking scheme.
1429  * This is because we cannot sleep with the original spinlock
1430  * held.
1431  */
1432 INDIRECT_CALLABLE_SCOPE
tcp_v6_do_rcv(struct sock * sk,struct sk_buff * skb)1433 int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1434 {
1435 	struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1436 	struct sk_buff *opt_skb = NULL;
1437 	enum skb_drop_reason reason;
1438 	struct tcp_sock *tp;
1439 
1440 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1441 	   goes to IPv4 receive handler and backlogged.
1442 	   From backlog it always goes here. Kerboom...
1443 	   Fortunately, tcp_rcv_established and rcv_established
1444 	   handle them correctly, but it is not case with
1445 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1446 	 */
1447 
1448 	if (skb->protocol == htons(ETH_P_IP))
1449 		return tcp_v4_do_rcv(sk, skb);
1450 
1451 	/*
1452 	 *	socket locking is here for SMP purposes as backlog rcv
1453 	 *	is currently called with bh processing disabled.
1454 	 */
1455 
1456 	/* Do Stevens' IPV6_PKTOPTIONS.
1457 
1458 	   Yes, guys, it is the only place in our code, where we
1459 	   may make it not affecting IPv4.
1460 	   The rest of code is protocol independent,
1461 	   and I do not like idea to uglify IPv4.
1462 
1463 	   Actually, all the idea behind IPV6_PKTOPTIONS
1464 	   looks not very well thought. For now we latch
1465 	   options, received in the last packet, enqueued
1466 	   by tcp. Feel free to propose better solution.
1467 					       --ANK (980728)
1468 	 */
1469 	if (np->rxopt.all)
1470 		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1471 
1472 	reason = SKB_DROP_REASON_NOT_SPECIFIED;
1473 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1474 		struct dst_entry *dst;
1475 
1476 		dst = rcu_dereference_protected(sk->sk_rx_dst,
1477 						lockdep_sock_is_held(sk));
1478 
1479 		sock_rps_save_rxhash(sk, skb);
1480 		sk_mark_napi_id(sk, skb);
1481 		if (dst) {
1482 			if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1483 			    INDIRECT_CALL_1(dst->ops->check, ip6_dst_check,
1484 					    dst, sk->sk_rx_dst_cookie) == NULL) {
1485 				RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1486 				dst_release(dst);
1487 			}
1488 		}
1489 
1490 		tcp_rcv_established(sk, skb);
1491 		if (opt_skb)
1492 			goto ipv6_pktoptions;
1493 		return 0;
1494 	}
1495 
1496 	if (tcp_checksum_complete(skb))
1497 		goto csum_err;
1498 
1499 	if (sk->sk_state == TCP_LISTEN) {
1500 		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1501 
1502 		if (!nsk)
1503 			goto discard;
1504 
1505 		if (nsk != sk) {
1506 			if (tcp_child_process(sk, nsk, skb))
1507 				goto reset;
1508 			if (opt_skb)
1509 				__kfree_skb(opt_skb);
1510 			return 0;
1511 		}
1512 	} else
1513 		sock_rps_save_rxhash(sk, skb);
1514 
1515 	if (tcp_rcv_state_process(sk, skb))
1516 		goto reset;
1517 	if (opt_skb)
1518 		goto ipv6_pktoptions;
1519 	return 0;
1520 
1521 reset:
1522 	tcp_v6_send_reset(sk, skb);
1523 discard:
1524 	if (opt_skb)
1525 		__kfree_skb(opt_skb);
1526 	kfree_skb_reason(skb, reason);
1527 	return 0;
1528 csum_err:
1529 	reason = SKB_DROP_REASON_TCP_CSUM;
1530 	trace_tcp_bad_csum(skb);
1531 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1532 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1533 	goto discard;
1534 
1535 
1536 ipv6_pktoptions:
1537 	/* Do you ask, what is it?
1538 
1539 	   1. skb was enqueued by tcp.
1540 	   2. skb is added to tail of read queue, rather than out of order.
1541 	   3. socket is not in passive state.
1542 	   4. Finally, it really contains options, which user wants to receive.
1543 	 */
1544 	tp = tcp_sk(sk);
1545 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1546 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1547 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1548 			np->mcast_oif = tcp_v6_iif(opt_skb);
1549 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1550 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1551 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1552 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1553 		if (np->repflow)
1554 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1555 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1556 			skb_set_owner_r(opt_skb, sk);
1557 			tcp_v6_restore_cb(opt_skb);
1558 			opt_skb = xchg(&np->pktoptions, opt_skb);
1559 		} else {
1560 			__kfree_skb(opt_skb);
1561 			opt_skb = xchg(&np->pktoptions, NULL);
1562 		}
1563 	}
1564 
1565 	consume_skb(opt_skb);
1566 	return 0;
1567 }
1568 
tcp_v6_fill_cb(struct sk_buff * skb,const struct ipv6hdr * hdr,const struct tcphdr * th)1569 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1570 			   const struct tcphdr *th)
1571 {
1572 	/* This is tricky: we move IP6CB at its correct location into
1573 	 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1574 	 * _decode_session6() uses IP6CB().
1575 	 * barrier() makes sure compiler won't play aliasing games.
1576 	 */
1577 	memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1578 		sizeof(struct inet6_skb_parm));
1579 	barrier();
1580 
1581 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1582 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1583 				    skb->len - th->doff*4);
1584 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1585 	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1586 	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1587 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1588 	TCP_SKB_CB(skb)->sacked = 0;
1589 	TCP_SKB_CB(skb)->has_rxtstamp =
1590 			skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1591 }
1592 
tcp_v6_rcv(struct sk_buff * skb)1593 INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
1594 {
1595 	enum skb_drop_reason drop_reason;
1596 	int sdif = inet6_sdif(skb);
1597 	int dif = inet6_iif(skb);
1598 	const struct tcphdr *th;
1599 	const struct ipv6hdr *hdr;
1600 	bool refcounted;
1601 	struct sock *sk;
1602 	int ret;
1603 	struct net *net = dev_net(skb->dev);
1604 
1605 	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1606 	if (skb->pkt_type != PACKET_HOST)
1607 		goto discard_it;
1608 
1609 	/*
1610 	 *	Count it even if it's bad.
1611 	 */
1612 	__TCP_INC_STATS(net, TCP_MIB_INSEGS);
1613 
1614 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1615 		goto discard_it;
1616 
1617 	th = (const struct tcphdr *)skb->data;
1618 
1619 	if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
1620 		drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
1621 		goto bad_packet;
1622 	}
1623 	if (!pskb_may_pull(skb, th->doff*4))
1624 		goto discard_it;
1625 
1626 	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1627 		goto csum_error;
1628 
1629 	th = (const struct tcphdr *)skb->data;
1630 	hdr = ipv6_hdr(skb);
1631 
1632 lookup:
1633 	sk = __inet6_lookup_skb(net->ipv4.tcp_death_row.hashinfo, skb, __tcp_hdrlen(th),
1634 				th->source, th->dest, inet6_iif(skb), sdif,
1635 				&refcounted);
1636 	if (!sk)
1637 		goto no_tcp_socket;
1638 
1639 process:
1640 	if (sk->sk_state == TCP_TIME_WAIT)
1641 		goto do_time_wait;
1642 
1643 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
1644 		struct request_sock *req = inet_reqsk(sk);
1645 		bool req_stolen = false;
1646 		struct sock *nsk;
1647 
1648 		sk = req->rsk_listener;
1649 		drop_reason = tcp_inbound_md5_hash(sk, skb,
1650 						   &hdr->saddr, &hdr->daddr,
1651 						   AF_INET6, dif, sdif);
1652 		if (drop_reason) {
1653 			sk_drops_add(sk, skb);
1654 			reqsk_put(req);
1655 			goto discard_it;
1656 		}
1657 		if (tcp_checksum_complete(skb)) {
1658 			reqsk_put(req);
1659 			goto csum_error;
1660 		}
1661 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
1662 			nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
1663 			if (!nsk) {
1664 				inet_csk_reqsk_queue_drop_and_put(sk, req);
1665 				goto lookup;
1666 			}
1667 			sk = nsk;
1668 			/* reuseport_migrate_sock() has already held one sk_refcnt
1669 			 * before returning.
1670 			 */
1671 		} else {
1672 			sock_hold(sk);
1673 		}
1674 		refcounted = true;
1675 		nsk = NULL;
1676 		if (!tcp_filter(sk, skb)) {
1677 			th = (const struct tcphdr *)skb->data;
1678 			hdr = ipv6_hdr(skb);
1679 			tcp_v6_fill_cb(skb, hdr, th);
1680 			nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1681 		} else {
1682 			drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1683 		}
1684 		if (!nsk) {
1685 			reqsk_put(req);
1686 			if (req_stolen) {
1687 				/* Another cpu got exclusive access to req
1688 				 * and created a full blown socket.
1689 				 * Try to feed this packet to this socket
1690 				 * instead of discarding it.
1691 				 */
1692 				tcp_v6_restore_cb(skb);
1693 				sock_put(sk);
1694 				goto lookup;
1695 			}
1696 			goto discard_and_relse;
1697 		}
1698 		if (nsk == sk) {
1699 			reqsk_put(req);
1700 			tcp_v6_restore_cb(skb);
1701 		} else if (tcp_child_process(sk, nsk, skb)) {
1702 			tcp_v6_send_reset(nsk, skb);
1703 			goto discard_and_relse;
1704 		} else {
1705 			sock_put(sk);
1706 			return 0;
1707 		}
1708 	}
1709 
1710 	if (static_branch_unlikely(&ip6_min_hopcount)) {
1711 		/* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
1712 		if (hdr->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) {
1713 			__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1714 			goto discard_and_relse;
1715 		}
1716 	}
1717 
1718 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
1719 		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
1720 		goto discard_and_relse;
1721 	}
1722 
1723 	drop_reason = tcp_inbound_md5_hash(sk, skb, &hdr->saddr, &hdr->daddr,
1724 					   AF_INET6, dif, sdif);
1725 	if (drop_reason)
1726 		goto discard_and_relse;
1727 
1728 	if (tcp_filter(sk, skb)) {
1729 		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1730 		goto discard_and_relse;
1731 	}
1732 	th = (const struct tcphdr *)skb->data;
1733 	hdr = ipv6_hdr(skb);
1734 	tcp_v6_fill_cb(skb, hdr, th);
1735 
1736 	skb->dev = NULL;
1737 
1738 	if (sk->sk_state == TCP_LISTEN) {
1739 		ret = tcp_v6_do_rcv(sk, skb);
1740 		goto put_and_return;
1741 	}
1742 
1743 	sk_incoming_cpu_update(sk);
1744 
1745 	bh_lock_sock_nested(sk);
1746 	tcp_segs_in(tcp_sk(sk), skb);
1747 	ret = 0;
1748 	if (!sock_owned_by_user(sk)) {
1749 		ret = tcp_v6_do_rcv(sk, skb);
1750 	} else {
1751 		if (tcp_add_backlog(sk, skb, &drop_reason))
1752 			goto discard_and_relse;
1753 	}
1754 	bh_unlock_sock(sk);
1755 put_and_return:
1756 	if (refcounted)
1757 		sock_put(sk);
1758 	return ret ? -1 : 0;
1759 
1760 no_tcp_socket:
1761 	drop_reason = SKB_DROP_REASON_NO_SOCKET;
1762 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1763 		goto discard_it;
1764 
1765 	tcp_v6_fill_cb(skb, hdr, th);
1766 
1767 	if (tcp_checksum_complete(skb)) {
1768 csum_error:
1769 		drop_reason = SKB_DROP_REASON_TCP_CSUM;
1770 		trace_tcp_bad_csum(skb);
1771 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1772 bad_packet:
1773 		__TCP_INC_STATS(net, TCP_MIB_INERRS);
1774 	} else {
1775 		tcp_v6_send_reset(NULL, skb);
1776 	}
1777 
1778 discard_it:
1779 	SKB_DR_OR(drop_reason, NOT_SPECIFIED);
1780 	kfree_skb_reason(skb, drop_reason);
1781 	return 0;
1782 
1783 discard_and_relse:
1784 	sk_drops_add(sk, skb);
1785 	if (refcounted)
1786 		sock_put(sk);
1787 	goto discard_it;
1788 
1789 do_time_wait:
1790 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1791 		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
1792 		inet_twsk_put(inet_twsk(sk));
1793 		goto discard_it;
1794 	}
1795 
1796 	tcp_v6_fill_cb(skb, hdr, th);
1797 
1798 	if (tcp_checksum_complete(skb)) {
1799 		inet_twsk_put(inet_twsk(sk));
1800 		goto csum_error;
1801 	}
1802 
1803 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1804 	case TCP_TW_SYN:
1805 	{
1806 		struct sock *sk2;
1807 
1808 		sk2 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
1809 					    skb, __tcp_hdrlen(th),
1810 					    &ipv6_hdr(skb)->saddr, th->source,
1811 					    &ipv6_hdr(skb)->daddr,
1812 					    ntohs(th->dest),
1813 					    tcp_v6_iif_l3_slave(skb),
1814 					    sdif);
1815 		if (sk2) {
1816 			struct inet_timewait_sock *tw = inet_twsk(sk);
1817 			inet_twsk_deschedule_put(tw);
1818 			sk = sk2;
1819 			tcp_v6_restore_cb(skb);
1820 			refcounted = false;
1821 			goto process;
1822 		}
1823 	}
1824 		/* to ACK */
1825 		fallthrough;
1826 	case TCP_TW_ACK:
1827 		tcp_v6_timewait_ack(sk, skb);
1828 		break;
1829 	case TCP_TW_RST:
1830 		tcp_v6_send_reset(sk, skb);
1831 		inet_twsk_deschedule_put(inet_twsk(sk));
1832 		goto discard_it;
1833 	case TCP_TW_SUCCESS:
1834 		;
1835 	}
1836 	goto discard_it;
1837 }
1838 
tcp_v6_early_demux(struct sk_buff * skb)1839 void tcp_v6_early_demux(struct sk_buff *skb)
1840 {
1841 	struct net *net = dev_net(skb->dev);
1842 	const struct ipv6hdr *hdr;
1843 	const struct tcphdr *th;
1844 	struct sock *sk;
1845 
1846 	if (skb->pkt_type != PACKET_HOST)
1847 		return;
1848 
1849 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1850 		return;
1851 
1852 	hdr = ipv6_hdr(skb);
1853 	th = tcp_hdr(skb);
1854 
1855 	if (th->doff < sizeof(struct tcphdr) / 4)
1856 		return;
1857 
1858 	/* Note : We use inet6_iif() here, not tcp_v6_iif() */
1859 	sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1860 					&hdr->saddr, th->source,
1861 					&hdr->daddr, ntohs(th->dest),
1862 					inet6_iif(skb), inet6_sdif(skb));
1863 	if (sk) {
1864 		skb->sk = sk;
1865 		skb->destructor = sock_edemux;
1866 		if (sk_fullsock(sk)) {
1867 			struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1868 
1869 			if (dst)
1870 				dst = dst_check(dst, sk->sk_rx_dst_cookie);
1871 			if (dst &&
1872 			    sk->sk_rx_dst_ifindex == skb->skb_iif)
1873 				skb_dst_set_noref(skb, dst);
1874 		}
1875 	}
1876 }
1877 
1878 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1879 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1880 	.twsk_unique	= tcp_twsk_unique,
1881 	.twsk_destructor = tcp_twsk_destructor,
1882 };
1883 
tcp_v6_send_check(struct sock * sk,struct sk_buff * skb)1884 INDIRECT_CALLABLE_SCOPE void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
1885 {
1886 	__tcp_v6_send_check(skb, &sk->sk_v6_rcv_saddr, &sk->sk_v6_daddr);
1887 }
1888 
1889 const struct inet_connection_sock_af_ops ipv6_specific = {
1890 	.queue_xmit	   = inet6_csk_xmit,
1891 	.send_check	   = tcp_v6_send_check,
1892 	.rebuild_header	   = inet6_sk_rebuild_header,
1893 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1894 	.conn_request	   = tcp_v6_conn_request,
1895 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1896 	.net_header_len	   = sizeof(struct ipv6hdr),
1897 	.net_frag_header_len = sizeof(struct frag_hdr),
1898 	.setsockopt	   = ipv6_setsockopt,
1899 	.getsockopt	   = ipv6_getsockopt,
1900 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1901 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1902 	.mtu_reduced	   = tcp_v6_mtu_reduced,
1903 };
1904 
1905 #ifdef CONFIG_TCP_MD5SIG
1906 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1907 	.md5_lookup	=	tcp_v6_md5_lookup,
1908 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1909 	.md5_parse	=	tcp_v6_parse_md5_keys,
1910 };
1911 #endif
1912 
1913 /*
1914  *	TCP over IPv4 via INET6 API
1915  */
1916 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1917 	.queue_xmit	   = ip_queue_xmit,
1918 	.send_check	   = tcp_v4_send_check,
1919 	.rebuild_header	   = inet_sk_rebuild_header,
1920 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1921 	.conn_request	   = tcp_v6_conn_request,
1922 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1923 	.net_header_len	   = sizeof(struct iphdr),
1924 	.setsockopt	   = ipv6_setsockopt,
1925 	.getsockopt	   = ipv6_getsockopt,
1926 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1927 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1928 	.mtu_reduced	   = tcp_v4_mtu_reduced,
1929 };
1930 
1931 #ifdef CONFIG_TCP_MD5SIG
1932 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1933 	.md5_lookup	=	tcp_v4_md5_lookup,
1934 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1935 	.md5_parse	=	tcp_v6_parse_md5_keys,
1936 };
1937 #endif
1938 
1939 /* NOTE: A lot of things set to zero explicitly by call to
1940  *       sk_alloc() so need not be done here.
1941  */
tcp_v6_init_sock(struct sock * sk)1942 static int tcp_v6_init_sock(struct sock *sk)
1943 {
1944 	struct inet_connection_sock *icsk = inet_csk(sk);
1945 
1946 	tcp_init_sock(sk);
1947 
1948 	icsk->icsk_af_ops = &ipv6_specific;
1949 
1950 #ifdef CONFIG_TCP_MD5SIG
1951 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1952 #endif
1953 
1954 	return 0;
1955 }
1956 
tcp_v6_destroy_sock(struct sock * sk)1957 static void tcp_v6_destroy_sock(struct sock *sk)
1958 {
1959 	tcp_v4_destroy_sock(sk);
1960 	inet6_destroy_sock(sk);
1961 }
1962 
1963 #ifdef CONFIG_PROC_FS
1964 /* Proc filesystem TCPv6 sock list dumping. */
get_openreq6(struct seq_file * seq,const struct request_sock * req,int i)1965 static void get_openreq6(struct seq_file *seq,
1966 			 const struct request_sock *req, int i)
1967 {
1968 	long ttd = req->rsk_timer.expires - jiffies;
1969 	const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1970 	const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1971 
1972 	if (ttd < 0)
1973 		ttd = 0;
1974 
1975 	seq_printf(seq,
1976 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1977 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1978 		   i,
1979 		   src->s6_addr32[0], src->s6_addr32[1],
1980 		   src->s6_addr32[2], src->s6_addr32[3],
1981 		   inet_rsk(req)->ir_num,
1982 		   dest->s6_addr32[0], dest->s6_addr32[1],
1983 		   dest->s6_addr32[2], dest->s6_addr32[3],
1984 		   ntohs(inet_rsk(req)->ir_rmt_port),
1985 		   TCP_SYN_RECV,
1986 		   0, 0, /* could print option size, but that is af dependent. */
1987 		   1,   /* timers active (only the expire timer) */
1988 		   jiffies_to_clock_t(ttd),
1989 		   req->num_timeout,
1990 		   from_kuid_munged(seq_user_ns(seq),
1991 				    sock_i_uid(req->rsk_listener)),
1992 		   0,  /* non standard timer */
1993 		   0, /* open_requests have no inode */
1994 		   0, req);
1995 }
1996 
get_tcp6_sock(struct seq_file * seq,struct sock * sp,int i)1997 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1998 {
1999 	const struct in6_addr *dest, *src;
2000 	__u16 destp, srcp;
2001 	int timer_active;
2002 	unsigned long timer_expires;
2003 	const struct inet_sock *inet = inet_sk(sp);
2004 	const struct tcp_sock *tp = tcp_sk(sp);
2005 	const struct inet_connection_sock *icsk = inet_csk(sp);
2006 	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2007 	int rx_queue;
2008 	int state;
2009 
2010 	dest  = &sp->sk_v6_daddr;
2011 	src   = &sp->sk_v6_rcv_saddr;
2012 	destp = ntohs(inet->inet_dport);
2013 	srcp  = ntohs(inet->inet_sport);
2014 
2015 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2016 	    icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2017 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2018 		timer_active	= 1;
2019 		timer_expires	= icsk->icsk_timeout;
2020 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2021 		timer_active	= 4;
2022 		timer_expires	= icsk->icsk_timeout;
2023 	} else if (timer_pending(&sp->sk_timer)) {
2024 		timer_active	= 2;
2025 		timer_expires	= sp->sk_timer.expires;
2026 	} else {
2027 		timer_active	= 0;
2028 		timer_expires = jiffies;
2029 	}
2030 
2031 	state = inet_sk_state_load(sp);
2032 	if (state == TCP_LISTEN)
2033 		rx_queue = READ_ONCE(sp->sk_ack_backlog);
2034 	else
2035 		/* Because we don't lock the socket,
2036 		 * we might find a transient negative value.
2037 		 */
2038 		rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2039 				      READ_ONCE(tp->copied_seq), 0);
2040 
2041 	seq_printf(seq,
2042 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2043 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
2044 		   i,
2045 		   src->s6_addr32[0], src->s6_addr32[1],
2046 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
2047 		   dest->s6_addr32[0], dest->s6_addr32[1],
2048 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
2049 		   state,
2050 		   READ_ONCE(tp->write_seq) - tp->snd_una,
2051 		   rx_queue,
2052 		   timer_active,
2053 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
2054 		   icsk->icsk_retransmits,
2055 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
2056 		   icsk->icsk_probes_out,
2057 		   sock_i_ino(sp),
2058 		   refcount_read(&sp->sk_refcnt), sp,
2059 		   jiffies_to_clock_t(icsk->icsk_rto),
2060 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
2061 		   (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp),
2062 		   tcp_snd_cwnd(tp),
2063 		   state == TCP_LISTEN ?
2064 			fastopenq->max_qlen :
2065 			(tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
2066 		   );
2067 }
2068 
get_timewait6_sock(struct seq_file * seq,struct inet_timewait_sock * tw,int i)2069 static void get_timewait6_sock(struct seq_file *seq,
2070 			       struct inet_timewait_sock *tw, int i)
2071 {
2072 	long delta = tw->tw_timer.expires - jiffies;
2073 	const struct in6_addr *dest, *src;
2074 	__u16 destp, srcp;
2075 
2076 	dest = &tw->tw_v6_daddr;
2077 	src  = &tw->tw_v6_rcv_saddr;
2078 	destp = ntohs(tw->tw_dport);
2079 	srcp  = ntohs(tw->tw_sport);
2080 
2081 	seq_printf(seq,
2082 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2083 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2084 		   i,
2085 		   src->s6_addr32[0], src->s6_addr32[1],
2086 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
2087 		   dest->s6_addr32[0], dest->s6_addr32[1],
2088 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
2089 		   tw->tw_substate, 0, 0,
2090 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2091 		   refcount_read(&tw->tw_refcnt), tw);
2092 }
2093 
tcp6_seq_show(struct seq_file * seq,void * v)2094 static int tcp6_seq_show(struct seq_file *seq, void *v)
2095 {
2096 	struct tcp_iter_state *st;
2097 	struct sock *sk = v;
2098 
2099 	if (v == SEQ_START_TOKEN) {
2100 		seq_puts(seq,
2101 			 "  sl  "
2102 			 "local_address                         "
2103 			 "remote_address                        "
2104 			 "st tx_queue rx_queue tr tm->when retrnsmt"
2105 			 "   uid  timeout inode\n");
2106 		goto out;
2107 	}
2108 	st = seq->private;
2109 
2110 	if (sk->sk_state == TCP_TIME_WAIT)
2111 		get_timewait6_sock(seq, v, st->num);
2112 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
2113 		get_openreq6(seq, v, st->num);
2114 	else
2115 		get_tcp6_sock(seq, v, st->num);
2116 out:
2117 	return 0;
2118 }
2119 
2120 static const struct seq_operations tcp6_seq_ops = {
2121 	.show		= tcp6_seq_show,
2122 	.start		= tcp_seq_start,
2123 	.next		= tcp_seq_next,
2124 	.stop		= tcp_seq_stop,
2125 };
2126 
2127 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2128 	.family		= AF_INET6,
2129 };
2130 
tcp6_proc_init(struct net * net)2131 int __net_init tcp6_proc_init(struct net *net)
2132 {
2133 	if (!proc_create_net_data("tcp6", 0444, net->proc_net, &tcp6_seq_ops,
2134 			sizeof(struct tcp_iter_state), &tcp6_seq_afinfo))
2135 		return -ENOMEM;
2136 	return 0;
2137 }
2138 
tcp6_proc_exit(struct net * net)2139 void tcp6_proc_exit(struct net *net)
2140 {
2141 	remove_proc_entry("tcp6", net->proc_net);
2142 }
2143 #endif
2144 
2145 struct proto tcpv6_prot = {
2146 	.name			= "TCPv6",
2147 	.owner			= THIS_MODULE,
2148 	.close			= tcp_close,
2149 	.pre_connect		= tcp_v6_pre_connect,
2150 	.connect		= tcp_v6_connect,
2151 	.disconnect		= tcp_disconnect,
2152 	.accept			= inet_csk_accept,
2153 	.ioctl			= tcp_ioctl,
2154 	.init			= tcp_v6_init_sock,
2155 	.destroy		= tcp_v6_destroy_sock,
2156 	.shutdown		= tcp_shutdown,
2157 	.setsockopt		= tcp_setsockopt,
2158 	.getsockopt		= tcp_getsockopt,
2159 	.bpf_bypass_getsockopt	= tcp_bpf_bypass_getsockopt,
2160 	.keepalive		= tcp_set_keepalive,
2161 	.recvmsg		= tcp_recvmsg,
2162 	.sendmsg		= tcp_sendmsg,
2163 	.sendpage		= tcp_sendpage,
2164 	.backlog_rcv		= tcp_v6_do_rcv,
2165 	.release_cb		= tcp_release_cb,
2166 	.hash			= inet6_hash,
2167 	.unhash			= inet_unhash,
2168 	.get_port		= inet_csk_get_port,
2169 	.put_port		= inet_put_port,
2170 #ifdef CONFIG_BPF_SYSCALL
2171 	.psock_update_sk_prot	= tcp_bpf_update_proto,
2172 #endif
2173 	.enter_memory_pressure	= tcp_enter_memory_pressure,
2174 	.leave_memory_pressure	= tcp_leave_memory_pressure,
2175 	.stream_memory_free	= tcp_stream_memory_free,
2176 	.sockets_allocated	= &tcp_sockets_allocated,
2177 
2178 	.memory_allocated	= &tcp_memory_allocated,
2179 	.per_cpu_fw_alloc	= &tcp_memory_per_cpu_fw_alloc,
2180 
2181 	.memory_pressure	= &tcp_memory_pressure,
2182 	.orphan_count		= &tcp_orphan_count,
2183 	.sysctl_mem		= sysctl_tcp_mem,
2184 	.sysctl_wmem_offset	= offsetof(struct net, ipv4.sysctl_tcp_wmem),
2185 	.sysctl_rmem_offset	= offsetof(struct net, ipv4.sysctl_tcp_rmem),
2186 	.max_header		= MAX_TCP_HEADER,
2187 	.obj_size		= sizeof(struct tcp6_sock),
2188 	.slab_flags		= SLAB_TYPESAFE_BY_RCU,
2189 	.twsk_prot		= &tcp6_timewait_sock_ops,
2190 	.rsk_prot		= &tcp6_request_sock_ops,
2191 	.h.hashinfo		= NULL,
2192 	.no_autobind		= true,
2193 	.diag_destroy		= tcp_abort,
2194 };
2195 EXPORT_SYMBOL_GPL(tcpv6_prot);
2196 
2197 static const struct inet6_protocol tcpv6_protocol = {
2198 	.handler	=	tcp_v6_rcv,
2199 	.err_handler	=	tcp_v6_err,
2200 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2201 };
2202 
2203 static struct inet_protosw tcpv6_protosw = {
2204 	.type		=	SOCK_STREAM,
2205 	.protocol	=	IPPROTO_TCP,
2206 	.prot		=	&tcpv6_prot,
2207 	.ops		=	&inet6_stream_ops,
2208 	.flags		=	INET_PROTOSW_PERMANENT |
2209 				INET_PROTOSW_ICSK,
2210 };
2211 
tcpv6_net_init(struct net * net)2212 static int __net_init tcpv6_net_init(struct net *net)
2213 {
2214 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2215 				    SOCK_RAW, IPPROTO_TCP, net);
2216 }
2217 
tcpv6_net_exit(struct net * net)2218 static void __net_exit tcpv6_net_exit(struct net *net)
2219 {
2220 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2221 }
2222 
tcpv6_net_exit_batch(struct list_head * net_exit_list)2223 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2224 {
2225 	tcp_twsk_purge(net_exit_list, AF_INET6);
2226 }
2227 
2228 static struct pernet_operations tcpv6_net_ops = {
2229 	.init	    = tcpv6_net_init,
2230 	.exit	    = tcpv6_net_exit,
2231 	.exit_batch = tcpv6_net_exit_batch,
2232 };
2233 
tcpv6_init(void)2234 int __init tcpv6_init(void)
2235 {
2236 	int ret;
2237 
2238 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2239 	if (ret)
2240 		goto out;
2241 
2242 	/* register inet6 protocol */
2243 	ret = inet6_register_protosw(&tcpv6_protosw);
2244 	if (ret)
2245 		goto out_tcpv6_protocol;
2246 
2247 	ret = register_pernet_subsys(&tcpv6_net_ops);
2248 	if (ret)
2249 		goto out_tcpv6_protosw;
2250 
2251 	ret = mptcpv6_init();
2252 	if (ret)
2253 		goto out_tcpv6_pernet_subsys;
2254 
2255 out:
2256 	return ret;
2257 
2258 out_tcpv6_pernet_subsys:
2259 	unregister_pernet_subsys(&tcpv6_net_ops);
2260 out_tcpv6_protosw:
2261 	inet6_unregister_protosw(&tcpv6_protosw);
2262 out_tcpv6_protocol:
2263 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2264 	goto out;
2265 }
2266 
tcpv6_exit(void)2267 void tcpv6_exit(void)
2268 {
2269 	unregister_pernet_subsys(&tcpv6_net_ops);
2270 	inet6_unregister_protosw(&tcpv6_protosw);
2271 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2272 }
2273