xref: /linux/net/ipv6/af_inet6.c (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	PF_INET6 socket protocol family
4  *	Linux INET6 implementation
5  *
6  *	Authors:
7  *	Pedro Roque		<roque@di.fc.ul.pt>
8  *
9  *	Adapted from linux/net/ipv4/af_inet.c
10  *
11  *	Fixes:
12  *	piggy, Karl Knutson	:	Socket protocol table
13  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
14  *	Arnaldo Melo		:	check proc_net_create return, cleanups
15  */
16 
17 #define pr_fmt(fmt) "IPv6: " fmt
18 
19 #include <linux/module.h>
20 #include <linux/capability.h>
21 #include <linux/errno.h>
22 #include <linux/types.h>
23 #include <linux/socket.h>
24 #include <linux/in.h>
25 #include <linux/kernel.h>
26 #include <linux/timer.h>
27 #include <linux/string.h>
28 #include <linux/sockios.h>
29 #include <linux/net.h>
30 #include <linux/fcntl.h>
31 #include <linux/mm.h>
32 #include <linux/interrupt.h>
33 #include <linux/proc_fs.h>
34 #include <linux/stat.h>
35 #include <linux/init.h>
36 #include <linux/slab.h>
37 
38 #include <linux/inet.h>
39 #include <linux/netdevice.h>
40 #include <linux/icmpv6.h>
41 #include <linux/netfilter_ipv6.h>
42 
43 #include <net/ip.h>
44 #include <net/ipv6.h>
45 #include <net/udp.h>
46 #include <net/udplite.h>
47 #include <net/tcp.h>
48 #include <net/ping.h>
49 #include <net/protocol.h>
50 #include <net/inet_common.h>
51 #include <net/route.h>
52 #include <net/transp_v6.h>
53 #include <net/ip6_route.h>
54 #include <net/addrconf.h>
55 #include <net/ipv6_stubs.h>
56 #include <net/ndisc.h>
57 #ifdef CONFIG_IPV6_TUNNEL
58 #include <net/ip6_tunnel.h>
59 #endif
60 #include <net/calipso.h>
61 #include <net/seg6.h>
62 
63 #include <linux/uaccess.h>
64 #include <linux/mroute6.h>
65 
66 #include "ip6_offload.h"
67 
68 MODULE_AUTHOR("Cast of dozens");
69 MODULE_DESCRIPTION("IPv6 protocol stack for Linux");
70 MODULE_LICENSE("GPL");
71 
72 /* The inetsw6 table contains everything that inet6_create needs to
73  * build a new socket.
74  */
75 static struct list_head inetsw6[SOCK_MAX];
76 static DEFINE_SPINLOCK(inetsw6_lock);
77 
78 struct ipv6_params ipv6_defaults = {
79 	.disable_ipv6 = 0,
80 	.autoconf = 1,
81 };
82 
83 static int disable_ipv6_mod;
84 
85 module_param_named(disable, disable_ipv6_mod, int, 0444);
86 MODULE_PARM_DESC(disable, "Disable IPv6 module such that it is non-functional");
87 
88 module_param_named(disable_ipv6, ipv6_defaults.disable_ipv6, int, 0444);
89 MODULE_PARM_DESC(disable_ipv6, "Disable IPv6 on all interfaces");
90 
91 module_param_named(autoconf, ipv6_defaults.autoconf, int, 0444);
92 MODULE_PARM_DESC(autoconf, "Enable IPv6 address autoconfiguration on all interfaces");
93 
94 bool ipv6_mod_enabled(void)
95 {
96 	return disable_ipv6_mod == 0;
97 }
98 EXPORT_SYMBOL_GPL(ipv6_mod_enabled);
99 
100 static __inline__ struct ipv6_pinfo *inet6_sk_generic(struct sock *sk)
101 {
102 	const int offset = sk->sk_prot->obj_size - sizeof(struct ipv6_pinfo);
103 
104 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
105 }
106 
107 static int inet6_create(struct net *net, struct socket *sock, int protocol,
108 			int kern)
109 {
110 	struct inet_sock *inet;
111 	struct ipv6_pinfo *np;
112 	struct sock *sk;
113 	struct inet_protosw *answer;
114 	struct proto *answer_prot;
115 	unsigned char answer_flags;
116 	int try_loading_module = 0;
117 	int err;
118 
119 	if (protocol < 0 || protocol >= IPPROTO_MAX)
120 		return -EINVAL;
121 
122 	/* Look for the requested type/protocol pair. */
123 lookup_protocol:
124 	err = -ESOCKTNOSUPPORT;
125 	rcu_read_lock();
126 	list_for_each_entry_rcu(answer, &inetsw6[sock->type], list) {
127 
128 		err = 0;
129 		/* Check the non-wild match. */
130 		if (protocol == answer->protocol) {
131 			if (protocol != IPPROTO_IP)
132 				break;
133 		} else {
134 			/* Check for the two wild cases. */
135 			if (IPPROTO_IP == protocol) {
136 				protocol = answer->protocol;
137 				break;
138 			}
139 			if (IPPROTO_IP == answer->protocol)
140 				break;
141 		}
142 		err = -EPROTONOSUPPORT;
143 	}
144 
145 	if (err) {
146 		if (try_loading_module < 2) {
147 			rcu_read_unlock();
148 			/*
149 			 * Be more specific, e.g. net-pf-10-proto-132-type-1
150 			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP-type-SOCK_STREAM)
151 			 */
152 			if (++try_loading_module == 1)
153 				request_module("net-pf-%d-proto-%d-type-%d",
154 						PF_INET6, protocol, sock->type);
155 			/*
156 			 * Fall back to generic, e.g. net-pf-10-proto-132
157 			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP)
158 			 */
159 			else
160 				request_module("net-pf-%d-proto-%d",
161 						PF_INET6, protocol);
162 			goto lookup_protocol;
163 		} else
164 			goto out_rcu_unlock;
165 	}
166 
167 	err = -EPERM;
168 	if (sock->type == SOCK_RAW && !kern &&
169 	    !ns_capable(net->user_ns, CAP_NET_RAW))
170 		goto out_rcu_unlock;
171 
172 	sock->ops = answer->ops;
173 	answer_prot = answer->prot;
174 	answer_flags = answer->flags;
175 	rcu_read_unlock();
176 
177 	WARN_ON(!answer_prot->slab);
178 
179 	err = -ENOBUFS;
180 	sk = sk_alloc(net, PF_INET6, GFP_KERNEL, answer_prot, kern);
181 	if (!sk)
182 		goto out;
183 
184 	sock_init_data(sock, sk);
185 
186 	err = 0;
187 	if (INET_PROTOSW_REUSE & answer_flags)
188 		sk->sk_reuse = SK_CAN_REUSE;
189 
190 	inet = inet_sk(sk);
191 	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
192 
193 	if (SOCK_RAW == sock->type) {
194 		inet->inet_num = protocol;
195 		if (IPPROTO_RAW == protocol)
196 			inet->hdrincl = 1;
197 	}
198 
199 	sk->sk_destruct		= inet_sock_destruct;
200 	sk->sk_family		= PF_INET6;
201 	sk->sk_protocol		= protocol;
202 
203 	sk->sk_backlog_rcv	= answer->prot->backlog_rcv;
204 
205 	inet_sk(sk)->pinet6 = np = inet6_sk_generic(sk);
206 	np->hop_limit	= -1;
207 	np->mcast_hops	= IPV6_DEFAULT_MCASTHOPS;
208 	np->mc_loop	= 1;
209 	np->mc_all	= 1;
210 	np->pmtudisc	= IPV6_PMTUDISC_WANT;
211 	np->repflow	= net->ipv6.sysctl.flowlabel_reflect;
212 	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;
213 
214 	/* Init the ipv4 part of the socket since we can have sockets
215 	 * using v6 API for ipv4.
216 	 */
217 	inet->uc_ttl	= -1;
218 
219 	inet->mc_loop	= 1;
220 	inet->mc_ttl	= 1;
221 	inet->mc_index	= 0;
222 	inet->mc_list	= NULL;
223 	inet->rcv_tos	= 0;
224 
225 	if (net->ipv4.sysctl_ip_no_pmtu_disc)
226 		inet->pmtudisc = IP_PMTUDISC_DONT;
227 	else
228 		inet->pmtudisc = IP_PMTUDISC_WANT;
229 	/*
230 	 * Increment only the relevant sk_prot->socks debug field, this changes
231 	 * the previous behaviour of incrementing both the equivalent to
232 	 * answer->prot->socks (inet6_sock_nr) and inet_sock_nr.
233 	 *
234 	 * This allows better debug granularity as we'll know exactly how many
235 	 * UDPv6, TCPv6, etc socks were allocated, not the sum of all IPv6
236 	 * transport protocol socks. -acme
237 	 */
238 	sk_refcnt_debug_inc(sk);
239 
240 	if (inet->inet_num) {
241 		/* It assumes that any protocol which allows
242 		 * the user to assign a number at socket
243 		 * creation time automatically shares.
244 		 */
245 		inet->inet_sport = htons(inet->inet_num);
246 		err = sk->sk_prot->hash(sk);
247 		if (err) {
248 			sk_common_release(sk);
249 			goto out;
250 		}
251 	}
252 	if (sk->sk_prot->init) {
253 		err = sk->sk_prot->init(sk);
254 		if (err) {
255 			sk_common_release(sk);
256 			goto out;
257 		}
258 	}
259 
260 	if (!kern) {
261 		err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
262 		if (err) {
263 			sk_common_release(sk);
264 			goto out;
265 		}
266 	}
267 out:
268 	return err;
269 out_rcu_unlock:
270 	rcu_read_unlock();
271 	goto out;
272 }
273 
274 static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
275 			bool force_bind_address_no_port, bool with_lock)
276 {
277 	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr;
278 	struct inet_sock *inet = inet_sk(sk);
279 	struct ipv6_pinfo *np = inet6_sk(sk);
280 	struct net *net = sock_net(sk);
281 	__be32 v4addr = 0;
282 	unsigned short snum;
283 	bool saved_ipv6only;
284 	int addr_type = 0;
285 	int err = 0;
286 
287 	if (addr->sin6_family != AF_INET6)
288 		return -EAFNOSUPPORT;
289 
290 	addr_type = ipv6_addr_type(&addr->sin6_addr);
291 	if ((addr_type & IPV6_ADDR_MULTICAST) && sk->sk_type == SOCK_STREAM)
292 		return -EINVAL;
293 
294 	snum = ntohs(addr->sin6_port);
295 	if (snum && snum < inet_prot_sock(net) &&
296 	    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
297 		return -EACCES;
298 
299 	if (with_lock)
300 		lock_sock(sk);
301 
302 	/* Check these errors (active socket, double bind). */
303 	if (sk->sk_state != TCP_CLOSE || inet->inet_num) {
304 		err = -EINVAL;
305 		goto out;
306 	}
307 
308 	/* Check if the address belongs to the host. */
309 	if (addr_type == IPV6_ADDR_MAPPED) {
310 		struct net_device *dev = NULL;
311 		int chk_addr_ret;
312 
313 		/* Binding to v4-mapped address on a v6-only socket
314 		 * makes no sense
315 		 */
316 		if (sk->sk_ipv6only) {
317 			err = -EINVAL;
318 			goto out;
319 		}
320 
321 		rcu_read_lock();
322 		if (sk->sk_bound_dev_if) {
323 			dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
324 			if (!dev) {
325 				err = -ENODEV;
326 				goto out_unlock;
327 			}
328 		}
329 
330 		/* Reproduce AF_INET checks to make the bindings consistent */
331 		v4addr = addr->sin6_addr.s6_addr32[3];
332 		chk_addr_ret = inet_addr_type_dev_table(net, dev, v4addr);
333 		rcu_read_unlock();
334 
335 		if (!inet_can_nonlocal_bind(net, inet) &&
336 		    v4addr != htonl(INADDR_ANY) &&
337 		    chk_addr_ret != RTN_LOCAL &&
338 		    chk_addr_ret != RTN_MULTICAST &&
339 		    chk_addr_ret != RTN_BROADCAST) {
340 			err = -EADDRNOTAVAIL;
341 			goto out;
342 		}
343 	} else {
344 		if (addr_type != IPV6_ADDR_ANY) {
345 			struct net_device *dev = NULL;
346 
347 			rcu_read_lock();
348 			if (__ipv6_addr_needs_scope_id(addr_type)) {
349 				if (addr_len >= sizeof(struct sockaddr_in6) &&
350 				    addr->sin6_scope_id) {
351 					/* Override any existing binding, if another one
352 					 * is supplied by user.
353 					 */
354 					sk->sk_bound_dev_if = addr->sin6_scope_id;
355 				}
356 
357 				/* Binding to link-local address requires an interface */
358 				if (!sk->sk_bound_dev_if) {
359 					err = -EINVAL;
360 					goto out_unlock;
361 				}
362 			}
363 
364 			if (sk->sk_bound_dev_if) {
365 				dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
366 				if (!dev) {
367 					err = -ENODEV;
368 					goto out_unlock;
369 				}
370 			}
371 
372 			/* ipv4 addr of the socket is invalid.  Only the
373 			 * unspecified and mapped address have a v4 equivalent.
374 			 */
375 			v4addr = LOOPBACK4_IPV6;
376 			if (!(addr_type & IPV6_ADDR_MULTICAST))	{
377 				if (!ipv6_can_nonlocal_bind(net, inet) &&
378 				    !ipv6_chk_addr(net, &addr->sin6_addr,
379 						   dev, 0)) {
380 					err = -EADDRNOTAVAIL;
381 					goto out_unlock;
382 				}
383 			}
384 			rcu_read_unlock();
385 		}
386 	}
387 
388 	inet->inet_rcv_saddr = v4addr;
389 	inet->inet_saddr = v4addr;
390 
391 	sk->sk_v6_rcv_saddr = addr->sin6_addr;
392 
393 	if (!(addr_type & IPV6_ADDR_MULTICAST))
394 		np->saddr = addr->sin6_addr;
395 
396 	saved_ipv6only = sk->sk_ipv6only;
397 	if (addr_type != IPV6_ADDR_ANY && addr_type != IPV6_ADDR_MAPPED)
398 		sk->sk_ipv6only = 1;
399 
400 	/* Make sure we are allowed to bind here. */
401 	if (snum || !(inet->bind_address_no_port ||
402 		      force_bind_address_no_port)) {
403 		if (sk->sk_prot->get_port(sk, snum)) {
404 			sk->sk_ipv6only = saved_ipv6only;
405 			inet_reset_saddr(sk);
406 			err = -EADDRINUSE;
407 			goto out;
408 		}
409 		err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk);
410 		if (err) {
411 			sk->sk_ipv6only = saved_ipv6only;
412 			inet_reset_saddr(sk);
413 			goto out;
414 		}
415 	}
416 
417 	if (addr_type != IPV6_ADDR_ANY)
418 		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
419 	if (snum)
420 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
421 	inet->inet_sport = htons(inet->inet_num);
422 	inet->inet_dport = 0;
423 	inet->inet_daddr = 0;
424 out:
425 	if (with_lock)
426 		release_sock(sk);
427 	return err;
428 out_unlock:
429 	rcu_read_unlock();
430 	goto out;
431 }
432 
433 /* bind for INET6 API */
434 int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
435 {
436 	struct sock *sk = sock->sk;
437 	int err = 0;
438 
439 	/* If the socket has its own bind function then use it. */
440 	if (sk->sk_prot->bind)
441 		return sk->sk_prot->bind(sk, uaddr, addr_len);
442 
443 	if (addr_len < SIN6_LEN_RFC2133)
444 		return -EINVAL;
445 
446 	/* BPF prog is run before any checks are done so that if the prog
447 	 * changes context in a wrong way it will be caught.
448 	 */
449 	err = BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr);
450 	if (err)
451 		return err;
452 
453 	return __inet6_bind(sk, uaddr, addr_len, false, true);
454 }
455 EXPORT_SYMBOL(inet6_bind);
456 
457 int inet6_release(struct socket *sock)
458 {
459 	struct sock *sk = sock->sk;
460 
461 	if (!sk)
462 		return -EINVAL;
463 
464 	/* Free mc lists */
465 	ipv6_sock_mc_close(sk);
466 
467 	/* Free ac lists */
468 	ipv6_sock_ac_close(sk);
469 
470 	return inet_release(sock);
471 }
472 EXPORT_SYMBOL(inet6_release);
473 
474 void inet6_destroy_sock(struct sock *sk)
475 {
476 	struct ipv6_pinfo *np = inet6_sk(sk);
477 	struct sk_buff *skb;
478 	struct ipv6_txoptions *opt;
479 
480 	/* Release rx options */
481 
482 	skb = xchg(&np->pktoptions, NULL);
483 	kfree_skb(skb);
484 
485 	skb = xchg(&np->rxpmtu, NULL);
486 	kfree_skb(skb);
487 
488 	/* Free flowlabels */
489 	fl6_free_socklist(sk);
490 
491 	/* Free tx options */
492 
493 	opt = xchg((__force struct ipv6_txoptions **)&np->opt, NULL);
494 	if (opt) {
495 		atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
496 		txopt_put(opt);
497 	}
498 }
499 EXPORT_SYMBOL_GPL(inet6_destroy_sock);
500 
501 /*
502  *	This does both peername and sockname.
503  */
504 
505 int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
506 		 int peer)
507 {
508 	struct sockaddr_in6 *sin = (struct sockaddr_in6 *)uaddr;
509 	struct sock *sk = sock->sk;
510 	struct inet_sock *inet = inet_sk(sk);
511 	struct ipv6_pinfo *np = inet6_sk(sk);
512 
513 	sin->sin6_family = AF_INET6;
514 	sin->sin6_flowinfo = 0;
515 	sin->sin6_scope_id = 0;
516 	if (peer) {
517 		if (!inet->inet_dport)
518 			return -ENOTCONN;
519 		if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
520 		    peer == 1)
521 			return -ENOTCONN;
522 		sin->sin6_port = inet->inet_dport;
523 		sin->sin6_addr = sk->sk_v6_daddr;
524 		if (np->sndflow)
525 			sin->sin6_flowinfo = np->flow_label;
526 	} else {
527 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
528 			sin->sin6_addr = np->saddr;
529 		else
530 			sin->sin6_addr = sk->sk_v6_rcv_saddr;
531 
532 		sin->sin6_port = inet->inet_sport;
533 	}
534 	sin->sin6_scope_id = ipv6_iface_scope_id(&sin->sin6_addr,
535 						 sk->sk_bound_dev_if);
536 	return sizeof(*sin);
537 }
538 EXPORT_SYMBOL(inet6_getname);
539 
540 int inet6_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
541 {
542 	struct sock *sk = sock->sk;
543 	struct net *net = sock_net(sk);
544 
545 	switch (cmd) {
546 	case SIOCADDRT:
547 	case SIOCDELRT:
548 
549 		return ipv6_route_ioctl(net, cmd, (void __user *)arg);
550 
551 	case SIOCSIFADDR:
552 		return addrconf_add_ifaddr(net, (void __user *) arg);
553 	case SIOCDIFADDR:
554 		return addrconf_del_ifaddr(net, (void __user *) arg);
555 	case SIOCSIFDSTADDR:
556 		return addrconf_set_dstaddr(net, (void __user *) arg);
557 	default:
558 		if (!sk->sk_prot->ioctl)
559 			return -ENOIOCTLCMD;
560 		return sk->sk_prot->ioctl(sk, cmd, arg);
561 	}
562 	/*NOTREACHED*/
563 	return 0;
564 }
565 EXPORT_SYMBOL(inet6_ioctl);
566 
567 const struct proto_ops inet6_stream_ops = {
568 	.family		   = PF_INET6,
569 	.owner		   = THIS_MODULE,
570 	.release	   = inet6_release,
571 	.bind		   = inet6_bind,
572 	.connect	   = inet_stream_connect,	/* ok		*/
573 	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
574 	.accept		   = inet_accept,		/* ok		*/
575 	.getname	   = inet6_getname,
576 	.poll		   = tcp_poll,			/* ok		*/
577 	.ioctl		   = inet6_ioctl,		/* must change  */
578 	.gettstamp	   = sock_gettstamp,
579 	.listen		   = inet_listen,		/* ok		*/
580 	.shutdown	   = inet_shutdown,		/* ok		*/
581 	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
582 	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
583 	.sendmsg	   = inet_sendmsg,		/* ok		*/
584 	.recvmsg	   = inet_recvmsg,		/* ok		*/
585 #ifdef CONFIG_MMU
586 	.mmap		   = tcp_mmap,
587 #endif
588 	.sendpage	   = inet_sendpage,
589 	.sendmsg_locked    = tcp_sendmsg_locked,
590 	.sendpage_locked   = tcp_sendpage_locked,
591 	.splice_read	   = tcp_splice_read,
592 	.read_sock	   = tcp_read_sock,
593 	.peek_len	   = tcp_peek_len,
594 #ifdef CONFIG_COMPAT
595 	.compat_setsockopt = compat_sock_common_setsockopt,
596 	.compat_getsockopt = compat_sock_common_getsockopt,
597 #endif
598 	.set_rcvlowat	   = tcp_set_rcvlowat,
599 };
600 
601 const struct proto_ops inet6_dgram_ops = {
602 	.family		   = PF_INET6,
603 	.owner		   = THIS_MODULE,
604 	.release	   = inet6_release,
605 	.bind		   = inet6_bind,
606 	.connect	   = inet_dgram_connect,	/* ok		*/
607 	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
608 	.accept		   = sock_no_accept,		/* a do nothing	*/
609 	.getname	   = inet6_getname,
610 	.poll		   = udp_poll,			/* ok		*/
611 	.ioctl		   = inet6_ioctl,		/* must change  */
612 	.gettstamp	   = sock_gettstamp,
613 	.listen		   = sock_no_listen,		/* ok		*/
614 	.shutdown	   = inet_shutdown,		/* ok		*/
615 	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
616 	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
617 	.sendmsg	   = inet_sendmsg,		/* ok		*/
618 	.recvmsg	   = inet_recvmsg,		/* ok		*/
619 	.mmap		   = sock_no_mmap,
620 	.sendpage	   = sock_no_sendpage,
621 	.set_peek_off	   = sk_set_peek_off,
622 #ifdef CONFIG_COMPAT
623 	.compat_setsockopt = compat_sock_common_setsockopt,
624 	.compat_getsockopt = compat_sock_common_getsockopt,
625 #endif
626 };
627 
628 static const struct net_proto_family inet6_family_ops = {
629 	.family = PF_INET6,
630 	.create = inet6_create,
631 	.owner	= THIS_MODULE,
632 };
633 
634 int inet6_register_protosw(struct inet_protosw *p)
635 {
636 	struct list_head *lh;
637 	struct inet_protosw *answer;
638 	struct list_head *last_perm;
639 	int protocol = p->protocol;
640 	int ret;
641 
642 	spin_lock_bh(&inetsw6_lock);
643 
644 	ret = -EINVAL;
645 	if (p->type >= SOCK_MAX)
646 		goto out_illegal;
647 
648 	/* If we are trying to override a permanent protocol, bail. */
649 	answer = NULL;
650 	ret = -EPERM;
651 	last_perm = &inetsw6[p->type];
652 	list_for_each(lh, &inetsw6[p->type]) {
653 		answer = list_entry(lh, struct inet_protosw, list);
654 
655 		/* Check only the non-wild match. */
656 		if (INET_PROTOSW_PERMANENT & answer->flags) {
657 			if (protocol == answer->protocol)
658 				break;
659 			last_perm = lh;
660 		}
661 
662 		answer = NULL;
663 	}
664 	if (answer)
665 		goto out_permanent;
666 
667 	/* Add the new entry after the last permanent entry if any, so that
668 	 * the new entry does not override a permanent entry when matched with
669 	 * a wild-card protocol. But it is allowed to override any existing
670 	 * non-permanent entry.  This means that when we remove this entry, the
671 	 * system automatically returns to the old behavior.
672 	 */
673 	list_add_rcu(&p->list, last_perm);
674 	ret = 0;
675 out:
676 	spin_unlock_bh(&inetsw6_lock);
677 	return ret;
678 
679 out_permanent:
680 	pr_err("Attempt to override permanent protocol %d\n", protocol);
681 	goto out;
682 
683 out_illegal:
684 	pr_err("Ignoring attempt to register invalid socket type %d\n",
685 	       p->type);
686 	goto out;
687 }
688 EXPORT_SYMBOL(inet6_register_protosw);
689 
690 void
691 inet6_unregister_protosw(struct inet_protosw *p)
692 {
693 	if (INET_PROTOSW_PERMANENT & p->flags) {
694 		pr_err("Attempt to unregister permanent protocol %d\n",
695 		       p->protocol);
696 	} else {
697 		spin_lock_bh(&inetsw6_lock);
698 		list_del_rcu(&p->list);
699 		spin_unlock_bh(&inetsw6_lock);
700 
701 		synchronize_net();
702 	}
703 }
704 EXPORT_SYMBOL(inet6_unregister_protosw);
705 
706 int inet6_sk_rebuild_header(struct sock *sk)
707 {
708 	struct ipv6_pinfo *np = inet6_sk(sk);
709 	struct dst_entry *dst;
710 
711 	dst = __sk_dst_check(sk, np->dst_cookie);
712 
713 	if (!dst) {
714 		struct inet_sock *inet = inet_sk(sk);
715 		struct in6_addr *final_p, final;
716 		struct flowi6 fl6;
717 
718 		memset(&fl6, 0, sizeof(fl6));
719 		fl6.flowi6_proto = sk->sk_protocol;
720 		fl6.daddr = sk->sk_v6_daddr;
721 		fl6.saddr = np->saddr;
722 		fl6.flowlabel = np->flow_label;
723 		fl6.flowi6_oif = sk->sk_bound_dev_if;
724 		fl6.flowi6_mark = sk->sk_mark;
725 		fl6.fl6_dport = inet->inet_dport;
726 		fl6.fl6_sport = inet->inet_sport;
727 		fl6.flowi6_uid = sk->sk_uid;
728 		security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
729 
730 		rcu_read_lock();
731 		final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt),
732 					 &final);
733 		rcu_read_unlock();
734 
735 		dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
736 		if (IS_ERR(dst)) {
737 			sk->sk_route_caps = 0;
738 			sk->sk_err_soft = -PTR_ERR(dst);
739 			return PTR_ERR(dst);
740 		}
741 
742 		ip6_dst_store(sk, dst, NULL, NULL);
743 	}
744 
745 	return 0;
746 }
747 EXPORT_SYMBOL_GPL(inet6_sk_rebuild_header);
748 
749 bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb,
750 		       const struct inet6_skb_parm *opt)
751 {
752 	const struct ipv6_pinfo *np = inet6_sk(sk);
753 
754 	if (np->rxopt.all) {
755 		if (((opt->flags & IP6SKB_HOPBYHOP) &&
756 		     (np->rxopt.bits.hopopts || np->rxopt.bits.ohopopts)) ||
757 		    (ip6_flowinfo((struct ipv6hdr *) skb_network_header(skb)) &&
758 		     np->rxopt.bits.rxflow) ||
759 		    (opt->srcrt && (np->rxopt.bits.srcrt ||
760 		     np->rxopt.bits.osrcrt)) ||
761 		    ((opt->dst1 || opt->dst0) &&
762 		     (np->rxopt.bits.dstopts || np->rxopt.bits.odstopts)))
763 			return true;
764 	}
765 	return false;
766 }
767 EXPORT_SYMBOL_GPL(ipv6_opt_accepted);
768 
769 static struct packet_type ipv6_packet_type __read_mostly = {
770 	.type = cpu_to_be16(ETH_P_IPV6),
771 	.func = ipv6_rcv,
772 	.list_func = ipv6_list_rcv,
773 };
774 
775 static int __init ipv6_packet_init(void)
776 {
777 	dev_add_pack(&ipv6_packet_type);
778 	return 0;
779 }
780 
781 static void ipv6_packet_cleanup(void)
782 {
783 	dev_remove_pack(&ipv6_packet_type);
784 }
785 
786 static int __net_init ipv6_init_mibs(struct net *net)
787 {
788 	int i;
789 
790 	net->mib.udp_stats_in6 = alloc_percpu(struct udp_mib);
791 	if (!net->mib.udp_stats_in6)
792 		return -ENOMEM;
793 	net->mib.udplite_stats_in6 = alloc_percpu(struct udp_mib);
794 	if (!net->mib.udplite_stats_in6)
795 		goto err_udplite_mib;
796 	net->mib.ipv6_statistics = alloc_percpu(struct ipstats_mib);
797 	if (!net->mib.ipv6_statistics)
798 		goto err_ip_mib;
799 
800 	for_each_possible_cpu(i) {
801 		struct ipstats_mib *af_inet6_stats;
802 		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics, i);
803 		u64_stats_init(&af_inet6_stats->syncp);
804 	}
805 
806 
807 	net->mib.icmpv6_statistics = alloc_percpu(struct icmpv6_mib);
808 	if (!net->mib.icmpv6_statistics)
809 		goto err_icmp_mib;
810 	net->mib.icmpv6msg_statistics = kzalloc(sizeof(struct icmpv6msg_mib),
811 						GFP_KERNEL);
812 	if (!net->mib.icmpv6msg_statistics)
813 		goto err_icmpmsg_mib;
814 	return 0;
815 
816 err_icmpmsg_mib:
817 	free_percpu(net->mib.icmpv6_statistics);
818 err_icmp_mib:
819 	free_percpu(net->mib.ipv6_statistics);
820 err_ip_mib:
821 	free_percpu(net->mib.udplite_stats_in6);
822 err_udplite_mib:
823 	free_percpu(net->mib.udp_stats_in6);
824 	return -ENOMEM;
825 }
826 
827 static void ipv6_cleanup_mibs(struct net *net)
828 {
829 	free_percpu(net->mib.udp_stats_in6);
830 	free_percpu(net->mib.udplite_stats_in6);
831 	free_percpu(net->mib.ipv6_statistics);
832 	free_percpu(net->mib.icmpv6_statistics);
833 	kfree(net->mib.icmpv6msg_statistics);
834 }
835 
836 static int __net_init inet6_net_init(struct net *net)
837 {
838 	int err = 0;
839 
840 	net->ipv6.sysctl.bindv6only = 0;
841 	net->ipv6.sysctl.icmpv6_time = 1*HZ;
842 	net->ipv6.sysctl.icmpv6_echo_ignore_all = 0;
843 	net->ipv6.sysctl.icmpv6_echo_ignore_multicast = 0;
844 	net->ipv6.sysctl.icmpv6_echo_ignore_anycast = 0;
845 
846 	/* By default, rate limit error messages.
847 	 * Except for pmtu discovery, it would break it.
848 	 * proc_do_large_bitmap needs pointer to the bitmap.
849 	 */
850 	bitmap_set(net->ipv6.sysctl.icmpv6_ratemask, 0, ICMPV6_ERRMSG_MAX + 1);
851 	bitmap_clear(net->ipv6.sysctl.icmpv6_ratemask, ICMPV6_PKT_TOOBIG, 1);
852 	net->ipv6.sysctl.icmpv6_ratemask_ptr = net->ipv6.sysctl.icmpv6_ratemask;
853 
854 	net->ipv6.sysctl.flowlabel_consistency = 1;
855 	net->ipv6.sysctl.auto_flowlabels = IP6_DEFAULT_AUTO_FLOW_LABELS;
856 	net->ipv6.sysctl.idgen_retries = 3;
857 	net->ipv6.sysctl.idgen_delay = 1 * HZ;
858 	net->ipv6.sysctl.flowlabel_state_ranges = 0;
859 	net->ipv6.sysctl.max_dst_opts_cnt = IP6_DEFAULT_MAX_DST_OPTS_CNT;
860 	net->ipv6.sysctl.max_hbh_opts_cnt = IP6_DEFAULT_MAX_HBH_OPTS_CNT;
861 	net->ipv6.sysctl.max_dst_opts_len = IP6_DEFAULT_MAX_DST_OPTS_LEN;
862 	net->ipv6.sysctl.max_hbh_opts_len = IP6_DEFAULT_MAX_HBH_OPTS_LEN;
863 	atomic_set(&net->ipv6.fib6_sernum, 1);
864 
865 	err = ipv6_init_mibs(net);
866 	if (err)
867 		return err;
868 #ifdef CONFIG_PROC_FS
869 	err = udp6_proc_init(net);
870 	if (err)
871 		goto out;
872 	err = tcp6_proc_init(net);
873 	if (err)
874 		goto proc_tcp6_fail;
875 	err = ac6_proc_init(net);
876 	if (err)
877 		goto proc_ac6_fail;
878 #endif
879 	return err;
880 
881 #ifdef CONFIG_PROC_FS
882 proc_ac6_fail:
883 	tcp6_proc_exit(net);
884 proc_tcp6_fail:
885 	udp6_proc_exit(net);
886 out:
887 	ipv6_cleanup_mibs(net);
888 	return err;
889 #endif
890 }
891 
892 static void __net_exit inet6_net_exit(struct net *net)
893 {
894 #ifdef CONFIG_PROC_FS
895 	udp6_proc_exit(net);
896 	tcp6_proc_exit(net);
897 	ac6_proc_exit(net);
898 #endif
899 	ipv6_cleanup_mibs(net);
900 }
901 
902 static struct pernet_operations inet6_net_ops = {
903 	.init = inet6_net_init,
904 	.exit = inet6_net_exit,
905 };
906 
907 static int ipv6_route_input(struct sk_buff *skb)
908 {
909 	ip6_route_input(skb);
910 	return skb_dst(skb)->error;
911 }
912 
913 static const struct ipv6_stub ipv6_stub_impl = {
914 	.ipv6_sock_mc_join = ipv6_sock_mc_join,
915 	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
916 	.ipv6_dst_lookup   = ip6_dst_lookup,
917 	.ipv6_route_input  = ipv6_route_input,
918 	.fib6_get_table	   = fib6_get_table,
919 	.fib6_table_lookup = fib6_table_lookup,
920 	.fib6_lookup       = fib6_lookup,
921 	.fib6_select_path  = fib6_select_path,
922 	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
923 	.fib6_nh_init	   = fib6_nh_init,
924 	.fib6_nh_release   = fib6_nh_release,
925 	.udpv6_encap_enable = udpv6_encap_enable,
926 	.ndisc_send_na = ndisc_send_na,
927 	.nd_tbl	= &nd_tbl,
928 };
929 
930 static const struct ipv6_bpf_stub ipv6_bpf_stub_impl = {
931 	.inet6_bind = __inet6_bind,
932 	.udp6_lib_lookup = __udp6_lib_lookup,
933 };
934 
935 static int __init inet6_init(void)
936 {
937 	struct list_head *r;
938 	int err = 0;
939 
940 	sock_skb_cb_check_size(sizeof(struct inet6_skb_parm));
941 
942 	/* Register the socket-side information for inet6_create.  */
943 	for (r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
944 		INIT_LIST_HEAD(r);
945 
946 	if (disable_ipv6_mod) {
947 		pr_info("Loaded, but administratively disabled, reboot required to enable\n");
948 		goto out;
949 	}
950 
951 	err = proto_register(&tcpv6_prot, 1);
952 	if (err)
953 		goto out;
954 
955 	err = proto_register(&udpv6_prot, 1);
956 	if (err)
957 		goto out_unregister_tcp_proto;
958 
959 	err = proto_register(&udplitev6_prot, 1);
960 	if (err)
961 		goto out_unregister_udp_proto;
962 
963 	err = proto_register(&rawv6_prot, 1);
964 	if (err)
965 		goto out_unregister_udplite_proto;
966 
967 	err = proto_register(&pingv6_prot, 1);
968 	if (err)
969 		goto out_unregister_raw_proto;
970 
971 	/* We MUST register RAW sockets before we create the ICMP6,
972 	 * IGMP6, or NDISC control sockets.
973 	 */
974 	err = rawv6_init();
975 	if (err)
976 		goto out_unregister_ping_proto;
977 
978 	/* Register the family here so that the init calls below will
979 	 * be able to create sockets. (?? is this dangerous ??)
980 	 */
981 	err = sock_register(&inet6_family_ops);
982 	if (err)
983 		goto out_sock_register_fail;
984 
985 	/*
986 	 *	ipngwg API draft makes clear that the correct semantics
987 	 *	for TCP and UDP is to consider one TCP and UDP instance
988 	 *	in a host available by both INET and INET6 APIs and
989 	 *	able to communicate via both network protocols.
990 	 */
991 
992 	err = register_pernet_subsys(&inet6_net_ops);
993 	if (err)
994 		goto register_pernet_fail;
995 	err = ip6_mr_init();
996 	if (err)
997 		goto ipmr_fail;
998 	err = icmpv6_init();
999 	if (err)
1000 		goto icmp_fail;
1001 	err = ndisc_init();
1002 	if (err)
1003 		goto ndisc_fail;
1004 	err = igmp6_init();
1005 	if (err)
1006 		goto igmp_fail;
1007 
1008 	err = ipv6_netfilter_init();
1009 	if (err)
1010 		goto netfilter_fail;
1011 	/* Create /proc/foo6 entries. */
1012 #ifdef CONFIG_PROC_FS
1013 	err = -ENOMEM;
1014 	if (raw6_proc_init())
1015 		goto proc_raw6_fail;
1016 	if (udplite6_proc_init())
1017 		goto proc_udplite6_fail;
1018 	if (ipv6_misc_proc_init())
1019 		goto proc_misc6_fail;
1020 	if (if6_proc_init())
1021 		goto proc_if6_fail;
1022 #endif
1023 	err = ip6_route_init();
1024 	if (err)
1025 		goto ip6_route_fail;
1026 	err = ndisc_late_init();
1027 	if (err)
1028 		goto ndisc_late_fail;
1029 	err = ip6_flowlabel_init();
1030 	if (err)
1031 		goto ip6_flowlabel_fail;
1032 	err = ipv6_anycast_init();
1033 	if (err)
1034 		goto ipv6_anycast_fail;
1035 	err = addrconf_init();
1036 	if (err)
1037 		goto addrconf_fail;
1038 
1039 	/* Init v6 extension headers. */
1040 	err = ipv6_exthdrs_init();
1041 	if (err)
1042 		goto ipv6_exthdrs_fail;
1043 
1044 	err = ipv6_frag_init();
1045 	if (err)
1046 		goto ipv6_frag_fail;
1047 
1048 	/* Init v6 transport protocols. */
1049 	err = udpv6_init();
1050 	if (err)
1051 		goto udpv6_fail;
1052 
1053 	err = udplitev6_init();
1054 	if (err)
1055 		goto udplitev6_fail;
1056 
1057 	err = udpv6_offload_init();
1058 	if (err)
1059 		goto udpv6_offload_fail;
1060 
1061 	err = tcpv6_init();
1062 	if (err)
1063 		goto tcpv6_fail;
1064 
1065 	err = ipv6_packet_init();
1066 	if (err)
1067 		goto ipv6_packet_fail;
1068 
1069 	err = pingv6_init();
1070 	if (err)
1071 		goto pingv6_fail;
1072 
1073 	err = calipso_init();
1074 	if (err)
1075 		goto calipso_fail;
1076 
1077 	err = seg6_init();
1078 	if (err)
1079 		goto seg6_fail;
1080 
1081 	err = igmp6_late_init();
1082 	if (err)
1083 		goto igmp6_late_err;
1084 
1085 #ifdef CONFIG_SYSCTL
1086 	err = ipv6_sysctl_register();
1087 	if (err)
1088 		goto sysctl_fail;
1089 #endif
1090 
1091 	/* ensure that ipv6 stubs are visible only after ipv6 is ready */
1092 	wmb();
1093 	ipv6_stub = &ipv6_stub_impl;
1094 	ipv6_bpf_stub = &ipv6_bpf_stub_impl;
1095 out:
1096 	return err;
1097 
1098 #ifdef CONFIG_SYSCTL
1099 sysctl_fail:
1100 	igmp6_late_cleanup();
1101 #endif
1102 igmp6_late_err:
1103 	seg6_exit();
1104 seg6_fail:
1105 	calipso_exit();
1106 calipso_fail:
1107 	pingv6_exit();
1108 pingv6_fail:
1109 	ipv6_packet_cleanup();
1110 ipv6_packet_fail:
1111 	tcpv6_exit();
1112 tcpv6_fail:
1113 	udpv6_offload_exit();
1114 udpv6_offload_fail:
1115 	udplitev6_exit();
1116 udplitev6_fail:
1117 	udpv6_exit();
1118 udpv6_fail:
1119 	ipv6_frag_exit();
1120 ipv6_frag_fail:
1121 	ipv6_exthdrs_exit();
1122 ipv6_exthdrs_fail:
1123 	addrconf_cleanup();
1124 addrconf_fail:
1125 	ipv6_anycast_cleanup();
1126 ipv6_anycast_fail:
1127 	ip6_flowlabel_cleanup();
1128 ip6_flowlabel_fail:
1129 	ndisc_late_cleanup();
1130 ndisc_late_fail:
1131 	ip6_route_cleanup();
1132 ip6_route_fail:
1133 #ifdef CONFIG_PROC_FS
1134 	if6_proc_exit();
1135 proc_if6_fail:
1136 	ipv6_misc_proc_exit();
1137 proc_misc6_fail:
1138 	udplite6_proc_exit();
1139 proc_udplite6_fail:
1140 	raw6_proc_exit();
1141 proc_raw6_fail:
1142 #endif
1143 	ipv6_netfilter_fini();
1144 netfilter_fail:
1145 	igmp6_cleanup();
1146 igmp_fail:
1147 	ndisc_cleanup();
1148 ndisc_fail:
1149 	icmpv6_cleanup();
1150 icmp_fail:
1151 	ip6_mr_cleanup();
1152 ipmr_fail:
1153 	unregister_pernet_subsys(&inet6_net_ops);
1154 register_pernet_fail:
1155 	sock_unregister(PF_INET6);
1156 	rtnl_unregister_all(PF_INET6);
1157 out_sock_register_fail:
1158 	rawv6_exit();
1159 out_unregister_ping_proto:
1160 	proto_unregister(&pingv6_prot);
1161 out_unregister_raw_proto:
1162 	proto_unregister(&rawv6_prot);
1163 out_unregister_udplite_proto:
1164 	proto_unregister(&udplitev6_prot);
1165 out_unregister_udp_proto:
1166 	proto_unregister(&udpv6_prot);
1167 out_unregister_tcp_proto:
1168 	proto_unregister(&tcpv6_prot);
1169 	goto out;
1170 }
1171 module_init(inet6_init);
1172 
1173 MODULE_ALIAS_NETPROTO(PF_INET6);
1174