xref: /openbmc/linux/net/ipv6/af_inet6.c (revision 09bae3b6)
1 /*
2  *	PF_INET6 socket protocol family
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Adapted from linux/net/ipv4/af_inet.c
9  *
10  *	Fixes:
11  *	piggy, Karl Knutson	:	Socket protocol table
12  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
13  *	Arnaldo Melo		:	check proc_net_create return, cleanups
14  *
15  *	This program is free software; you can redistribute it and/or
16  *	modify it under the terms of the GNU General Public License
17  *	as published by the Free Software Foundation; either version
18  *	2 of the License, or (at your option) any later version.
19  */
20 
21 #define pr_fmt(fmt) "IPv6: " fmt
22 
23 #include <linux/module.h>
24 #include <linux/capability.h>
25 #include <linux/errno.h>
26 #include <linux/types.h>
27 #include <linux/socket.h>
28 #include <linux/in.h>
29 #include <linux/kernel.h>
30 #include <linux/timer.h>
31 #include <linux/string.h>
32 #include <linux/sockios.h>
33 #include <linux/net.h>
34 #include <linux/fcntl.h>
35 #include <linux/mm.h>
36 #include <linux/interrupt.h>
37 #include <linux/proc_fs.h>
38 #include <linux/stat.h>
39 #include <linux/init.h>
40 #include <linux/slab.h>
41 
42 #include <linux/inet.h>
43 #include <linux/netdevice.h>
44 #include <linux/icmpv6.h>
45 #include <linux/netfilter_ipv6.h>
46 
47 #include <net/ip.h>
48 #include <net/ipv6.h>
49 #include <net/udp.h>
50 #include <net/udplite.h>
51 #include <net/tcp.h>
52 #include <net/ping.h>
53 #include <net/protocol.h>
54 #include <net/inet_common.h>
55 #include <net/route.h>
56 #include <net/transp_v6.h>
57 #include <net/ip6_route.h>
58 #include <net/addrconf.h>
59 #include <net/ndisc.h>
60 #ifdef CONFIG_IPV6_TUNNEL
61 #include <net/ip6_tunnel.h>
62 #endif
63 #include <net/calipso.h>
64 #include <net/seg6.h>
65 
66 #include <linux/uaccess.h>
67 #include <linux/mroute6.h>
68 
69 #include "ip6_offload.h"
70 
71 MODULE_AUTHOR("Cast of dozens");
72 MODULE_DESCRIPTION("IPv6 protocol stack for Linux");
73 MODULE_LICENSE("GPL");
74 
75 /* The inetsw6 table contains everything that inet6_create needs to
76  * build a new socket.
77  */
78 static struct list_head inetsw6[SOCK_MAX];
79 static DEFINE_SPINLOCK(inetsw6_lock);
80 
81 struct ipv6_params ipv6_defaults = {
82 	.disable_ipv6 = 0,
83 	.autoconf = 1,
84 };
85 
86 static int disable_ipv6_mod;
87 
88 module_param_named(disable, disable_ipv6_mod, int, 0444);
89 MODULE_PARM_DESC(disable, "Disable IPv6 module such that it is non-functional");
90 
91 module_param_named(disable_ipv6, ipv6_defaults.disable_ipv6, int, 0444);
92 MODULE_PARM_DESC(disable_ipv6, "Disable IPv6 on all interfaces");
93 
94 module_param_named(autoconf, ipv6_defaults.autoconf, int, 0444);
95 MODULE_PARM_DESC(autoconf, "Enable IPv6 address autoconfiguration on all interfaces");
96 
97 bool ipv6_mod_enabled(void)
98 {
99 	return disable_ipv6_mod == 0;
100 }
101 EXPORT_SYMBOL_GPL(ipv6_mod_enabled);
102 
103 static __inline__ struct ipv6_pinfo *inet6_sk_generic(struct sock *sk)
104 {
105 	const int offset = sk->sk_prot->obj_size - sizeof(struct ipv6_pinfo);
106 
107 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
108 }
109 
110 static int inet6_create(struct net *net, struct socket *sock, int protocol,
111 			int kern)
112 {
113 	struct inet_sock *inet;
114 	struct ipv6_pinfo *np;
115 	struct sock *sk;
116 	struct inet_protosw *answer;
117 	struct proto *answer_prot;
118 	unsigned char answer_flags;
119 	int try_loading_module = 0;
120 	int err;
121 
122 	if (protocol < 0 || protocol >= IPPROTO_MAX)
123 		return -EINVAL;
124 
125 	/* Look for the requested type/protocol pair. */
126 lookup_protocol:
127 	err = -ESOCKTNOSUPPORT;
128 	rcu_read_lock();
129 	list_for_each_entry_rcu(answer, &inetsw6[sock->type], list) {
130 
131 		err = 0;
132 		/* Check the non-wild match. */
133 		if (protocol == answer->protocol) {
134 			if (protocol != IPPROTO_IP)
135 				break;
136 		} else {
137 			/* Check for the two wild cases. */
138 			if (IPPROTO_IP == protocol) {
139 				protocol = answer->protocol;
140 				break;
141 			}
142 			if (IPPROTO_IP == answer->protocol)
143 				break;
144 		}
145 		err = -EPROTONOSUPPORT;
146 	}
147 
148 	if (err) {
149 		if (try_loading_module < 2) {
150 			rcu_read_unlock();
151 			/*
152 			 * Be more specific, e.g. net-pf-10-proto-132-type-1
153 			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP-type-SOCK_STREAM)
154 			 */
155 			if (++try_loading_module == 1)
156 				request_module("net-pf-%d-proto-%d-type-%d",
157 						PF_INET6, protocol, sock->type);
158 			/*
159 			 * Fall back to generic, e.g. net-pf-10-proto-132
160 			 * (net-pf-PF_INET6-proto-IPPROTO_SCTP)
161 			 */
162 			else
163 				request_module("net-pf-%d-proto-%d",
164 						PF_INET6, protocol);
165 			goto lookup_protocol;
166 		} else
167 			goto out_rcu_unlock;
168 	}
169 
170 	err = -EPERM;
171 	if (sock->type == SOCK_RAW && !kern &&
172 	    !ns_capable(net->user_ns, CAP_NET_RAW))
173 		goto out_rcu_unlock;
174 
175 	sock->ops = answer->ops;
176 	answer_prot = answer->prot;
177 	answer_flags = answer->flags;
178 	rcu_read_unlock();
179 
180 	WARN_ON(!answer_prot->slab);
181 
182 	err = -ENOBUFS;
183 	sk = sk_alloc(net, PF_INET6, GFP_KERNEL, answer_prot, kern);
184 	if (!sk)
185 		goto out;
186 
187 	sock_init_data(sock, sk);
188 
189 	err = 0;
190 	if (INET_PROTOSW_REUSE & answer_flags)
191 		sk->sk_reuse = SK_CAN_REUSE;
192 
193 	inet = inet_sk(sk);
194 	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
195 
196 	if (SOCK_RAW == sock->type) {
197 		inet->inet_num = protocol;
198 		if (IPPROTO_RAW == protocol)
199 			inet->hdrincl = 1;
200 	}
201 
202 	sk->sk_destruct		= inet_sock_destruct;
203 	sk->sk_family		= PF_INET6;
204 	sk->sk_protocol		= protocol;
205 
206 	sk->sk_backlog_rcv	= answer->prot->backlog_rcv;
207 
208 	inet_sk(sk)->pinet6 = np = inet6_sk_generic(sk);
209 	np->hop_limit	= -1;
210 	np->mcast_hops	= IPV6_DEFAULT_MCASTHOPS;
211 	np->mc_loop	= 1;
212 	np->pmtudisc	= IPV6_PMTUDISC_WANT;
213 	np->repflow	= net->ipv6.sysctl.flowlabel_reflect;
214 	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;
215 
216 	/* Init the ipv4 part of the socket since we can have sockets
217 	 * using v6 API for ipv4.
218 	 */
219 	inet->uc_ttl	= -1;
220 
221 	inet->mc_loop	= 1;
222 	inet->mc_ttl	= 1;
223 	inet->mc_index	= 0;
224 	inet->mc_list	= NULL;
225 	inet->rcv_tos	= 0;
226 
227 	if (net->ipv4.sysctl_ip_no_pmtu_disc)
228 		inet->pmtudisc = IP_PMTUDISC_DONT;
229 	else
230 		inet->pmtudisc = IP_PMTUDISC_WANT;
231 	/*
232 	 * Increment only the relevant sk_prot->socks debug field, this changes
233 	 * the previous behaviour of incrementing both the equivalent to
234 	 * answer->prot->socks (inet6_sock_nr) and inet_sock_nr.
235 	 *
236 	 * This allows better debug granularity as we'll know exactly how many
237 	 * UDPv6, TCPv6, etc socks were allocated, not the sum of all IPv6
238 	 * transport protocol socks. -acme
239 	 */
240 	sk_refcnt_debug_inc(sk);
241 
242 	if (inet->inet_num) {
243 		/* It assumes that any protocol which allows
244 		 * the user to assign a number at socket
245 		 * creation time automatically shares.
246 		 */
247 		inet->inet_sport = htons(inet->inet_num);
248 		err = sk->sk_prot->hash(sk);
249 		if (err) {
250 			sk_common_release(sk);
251 			goto out;
252 		}
253 	}
254 	if (sk->sk_prot->init) {
255 		err = sk->sk_prot->init(sk);
256 		if (err) {
257 			sk_common_release(sk);
258 			goto out;
259 		}
260 	}
261 
262 	if (!kern) {
263 		err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
264 		if (err) {
265 			sk_common_release(sk);
266 			goto out;
267 		}
268 	}
269 out:
270 	return err;
271 out_rcu_unlock:
272 	rcu_read_unlock();
273 	goto out;
274 }
275 
276 static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
277 			bool force_bind_address_no_port, bool with_lock)
278 {
279 	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr;
280 	struct inet_sock *inet = inet_sk(sk);
281 	struct ipv6_pinfo *np = inet6_sk(sk);
282 	struct net *net = sock_net(sk);
283 	__be32 v4addr = 0;
284 	unsigned short snum;
285 	bool saved_ipv6only;
286 	int addr_type = 0;
287 	int err = 0;
288 
289 	if (addr->sin6_family != AF_INET6)
290 		return -EAFNOSUPPORT;
291 
292 	addr_type = ipv6_addr_type(&addr->sin6_addr);
293 	if ((addr_type & IPV6_ADDR_MULTICAST) && sk->sk_type == SOCK_STREAM)
294 		return -EINVAL;
295 
296 	snum = ntohs(addr->sin6_port);
297 	if (snum && snum < inet_prot_sock(net) &&
298 	    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
299 		return -EACCES;
300 
301 	if (with_lock)
302 		lock_sock(sk);
303 
304 	/* Check these errors (active socket, double bind). */
305 	if (sk->sk_state != TCP_CLOSE || inet->inet_num) {
306 		err = -EINVAL;
307 		goto out;
308 	}
309 
310 	/* Check if the address belongs to the host. */
311 	if (addr_type == IPV6_ADDR_MAPPED) {
312 		int chk_addr_ret;
313 
314 		/* Binding to v4-mapped address on a v6-only socket
315 		 * makes no sense
316 		 */
317 		if (sk->sk_ipv6only) {
318 			err = -EINVAL;
319 			goto out;
320 		}
321 
322 		/* Reproduce AF_INET checks to make the bindings consistent */
323 		v4addr = addr->sin6_addr.s6_addr32[3];
324 		chk_addr_ret = inet_addr_type(net, v4addr);
325 		if (!inet_can_nonlocal_bind(net, inet) &&
326 		    v4addr != htonl(INADDR_ANY) &&
327 		    chk_addr_ret != RTN_LOCAL &&
328 		    chk_addr_ret != RTN_MULTICAST &&
329 		    chk_addr_ret != RTN_BROADCAST) {
330 			err = -EADDRNOTAVAIL;
331 			goto out;
332 		}
333 	} else {
334 		if (addr_type != IPV6_ADDR_ANY) {
335 			struct net_device *dev = NULL;
336 
337 			rcu_read_lock();
338 			if (__ipv6_addr_needs_scope_id(addr_type)) {
339 				if (addr_len >= sizeof(struct sockaddr_in6) &&
340 				    addr->sin6_scope_id) {
341 					/* Override any existing binding, if another one
342 					 * is supplied by user.
343 					 */
344 					sk->sk_bound_dev_if = addr->sin6_scope_id;
345 				}
346 
347 				/* Binding to link-local address requires an interface */
348 				if (!sk->sk_bound_dev_if) {
349 					err = -EINVAL;
350 					goto out_unlock;
351 				}
352 				dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
353 				if (!dev) {
354 					err = -ENODEV;
355 					goto out_unlock;
356 				}
357 			}
358 
359 			/* ipv4 addr of the socket is invalid.  Only the
360 			 * unspecified and mapped address have a v4 equivalent.
361 			 */
362 			v4addr = LOOPBACK4_IPV6;
363 			if (!(addr_type & IPV6_ADDR_MULTICAST))	{
364 				if (!ipv6_can_nonlocal_bind(net, inet) &&
365 				    !ipv6_chk_addr(net, &addr->sin6_addr,
366 						   dev, 0)) {
367 					err = -EADDRNOTAVAIL;
368 					goto out_unlock;
369 				}
370 			}
371 			rcu_read_unlock();
372 		}
373 	}
374 
375 	inet->inet_rcv_saddr = v4addr;
376 	inet->inet_saddr = v4addr;
377 
378 	sk->sk_v6_rcv_saddr = addr->sin6_addr;
379 
380 	if (!(addr_type & IPV6_ADDR_MULTICAST))
381 		np->saddr = addr->sin6_addr;
382 
383 	saved_ipv6only = sk->sk_ipv6only;
384 	if (addr_type != IPV6_ADDR_ANY && addr_type != IPV6_ADDR_MAPPED)
385 		sk->sk_ipv6only = 1;
386 
387 	/* Make sure we are allowed to bind here. */
388 	if (snum || !(inet->bind_address_no_port ||
389 		      force_bind_address_no_port)) {
390 		if (sk->sk_prot->get_port(sk, snum)) {
391 			sk->sk_ipv6only = saved_ipv6only;
392 			inet_reset_saddr(sk);
393 			err = -EADDRINUSE;
394 			goto out;
395 		}
396 		err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk);
397 		if (err) {
398 			sk->sk_ipv6only = saved_ipv6only;
399 			inet_reset_saddr(sk);
400 			goto out;
401 		}
402 	}
403 
404 	if (addr_type != IPV6_ADDR_ANY)
405 		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
406 	if (snum)
407 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
408 	inet->inet_sport = htons(inet->inet_num);
409 	inet->inet_dport = 0;
410 	inet->inet_daddr = 0;
411 out:
412 	if (with_lock)
413 		release_sock(sk);
414 	return err;
415 out_unlock:
416 	rcu_read_unlock();
417 	goto out;
418 }
419 
420 /* bind for INET6 API */
421 int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
422 {
423 	struct sock *sk = sock->sk;
424 	int err = 0;
425 
426 	/* If the socket has its own bind function then use it. */
427 	if (sk->sk_prot->bind)
428 		return sk->sk_prot->bind(sk, uaddr, addr_len);
429 
430 	if (addr_len < SIN6_LEN_RFC2133)
431 		return -EINVAL;
432 
433 	/* BPF prog is run before any checks are done so that if the prog
434 	 * changes context in a wrong way it will be caught.
435 	 */
436 	err = BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr);
437 	if (err)
438 		return err;
439 
440 	return __inet6_bind(sk, uaddr, addr_len, false, true);
441 }
442 EXPORT_SYMBOL(inet6_bind);
443 
444 int inet6_release(struct socket *sock)
445 {
446 	struct sock *sk = sock->sk;
447 
448 	if (!sk)
449 		return -EINVAL;
450 
451 	/* Free mc lists */
452 	ipv6_sock_mc_close(sk);
453 
454 	/* Free ac lists */
455 	ipv6_sock_ac_close(sk);
456 
457 	return inet_release(sock);
458 }
459 EXPORT_SYMBOL(inet6_release);
460 
461 void inet6_destroy_sock(struct sock *sk)
462 {
463 	struct ipv6_pinfo *np = inet6_sk(sk);
464 	struct sk_buff *skb;
465 	struct ipv6_txoptions *opt;
466 
467 	/* Release rx options */
468 
469 	skb = xchg(&np->pktoptions, NULL);
470 	if (skb)
471 		kfree_skb(skb);
472 
473 	skb = xchg(&np->rxpmtu, NULL);
474 	if (skb)
475 		kfree_skb(skb);
476 
477 	/* Free flowlabels */
478 	fl6_free_socklist(sk);
479 
480 	/* Free tx options */
481 
482 	opt = xchg((__force struct ipv6_txoptions **)&np->opt, NULL);
483 	if (opt) {
484 		atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
485 		txopt_put(opt);
486 	}
487 }
488 EXPORT_SYMBOL_GPL(inet6_destroy_sock);
489 
490 /*
491  *	This does both peername and sockname.
492  */
493 
494 int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
495 		 int peer)
496 {
497 	struct sockaddr_in6 *sin = (struct sockaddr_in6 *)uaddr;
498 	struct sock *sk = sock->sk;
499 	struct inet_sock *inet = inet_sk(sk);
500 	struct ipv6_pinfo *np = inet6_sk(sk);
501 
502 	sin->sin6_family = AF_INET6;
503 	sin->sin6_flowinfo = 0;
504 	sin->sin6_scope_id = 0;
505 	if (peer) {
506 		if (!inet->inet_dport)
507 			return -ENOTCONN;
508 		if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
509 		    peer == 1)
510 			return -ENOTCONN;
511 		sin->sin6_port = inet->inet_dport;
512 		sin->sin6_addr = sk->sk_v6_daddr;
513 		if (np->sndflow)
514 			sin->sin6_flowinfo = np->flow_label;
515 	} else {
516 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
517 			sin->sin6_addr = np->saddr;
518 		else
519 			sin->sin6_addr = sk->sk_v6_rcv_saddr;
520 
521 		sin->sin6_port = inet->inet_sport;
522 	}
523 	sin->sin6_scope_id = ipv6_iface_scope_id(&sin->sin6_addr,
524 						 sk->sk_bound_dev_if);
525 	return sizeof(*sin);
526 }
527 EXPORT_SYMBOL(inet6_getname);
528 
529 int inet6_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
530 {
531 	struct sock *sk = sock->sk;
532 	struct net *net = sock_net(sk);
533 
534 	switch (cmd) {
535 	case SIOCGSTAMP:
536 		return sock_get_timestamp(sk, (struct timeval __user *)arg);
537 
538 	case SIOCGSTAMPNS:
539 		return sock_get_timestampns(sk, (struct timespec __user *)arg);
540 
541 	case SIOCADDRT:
542 	case SIOCDELRT:
543 
544 		return ipv6_route_ioctl(net, cmd, (void __user *)arg);
545 
546 	case SIOCSIFADDR:
547 		return addrconf_add_ifaddr(net, (void __user *) arg);
548 	case SIOCDIFADDR:
549 		return addrconf_del_ifaddr(net, (void __user *) arg);
550 	case SIOCSIFDSTADDR:
551 		return addrconf_set_dstaddr(net, (void __user *) arg);
552 	default:
553 		if (!sk->sk_prot->ioctl)
554 			return -ENOIOCTLCMD;
555 		return sk->sk_prot->ioctl(sk, cmd, arg);
556 	}
557 	/*NOTREACHED*/
558 	return 0;
559 }
560 EXPORT_SYMBOL(inet6_ioctl);
561 
562 const struct proto_ops inet6_stream_ops = {
563 	.family		   = PF_INET6,
564 	.owner		   = THIS_MODULE,
565 	.release	   = inet6_release,
566 	.bind		   = inet6_bind,
567 	.connect	   = inet_stream_connect,	/* ok		*/
568 	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
569 	.accept		   = inet_accept,		/* ok		*/
570 	.getname	   = inet6_getname,
571 	.poll		   = tcp_poll,			/* ok		*/
572 	.ioctl		   = inet6_ioctl,		/* must change  */
573 	.listen		   = inet_listen,		/* ok		*/
574 	.shutdown	   = inet_shutdown,		/* ok		*/
575 	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
576 	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
577 	.sendmsg	   = inet_sendmsg,		/* ok		*/
578 	.recvmsg	   = inet_recvmsg,		/* ok		*/
579 #ifdef CONFIG_MMU
580 	.mmap		   = tcp_mmap,
581 #endif
582 	.sendpage	   = inet_sendpage,
583 	.sendmsg_locked    = tcp_sendmsg_locked,
584 	.sendpage_locked   = tcp_sendpage_locked,
585 	.splice_read	   = tcp_splice_read,
586 	.read_sock	   = tcp_read_sock,
587 	.peek_len	   = tcp_peek_len,
588 #ifdef CONFIG_COMPAT
589 	.compat_setsockopt = compat_sock_common_setsockopt,
590 	.compat_getsockopt = compat_sock_common_getsockopt,
591 #endif
592 	.set_rcvlowat	   = tcp_set_rcvlowat,
593 };
594 
595 const struct proto_ops inet6_dgram_ops = {
596 	.family		   = PF_INET6,
597 	.owner		   = THIS_MODULE,
598 	.release	   = inet6_release,
599 	.bind		   = inet6_bind,
600 	.connect	   = inet_dgram_connect,	/* ok		*/
601 	.socketpair	   = sock_no_socketpair,	/* a do nothing	*/
602 	.accept		   = sock_no_accept,		/* a do nothing	*/
603 	.getname	   = inet6_getname,
604 	.poll		   = udp_poll,			/* ok		*/
605 	.ioctl		   = inet6_ioctl,		/* must change  */
606 	.listen		   = sock_no_listen,		/* ok		*/
607 	.shutdown	   = inet_shutdown,		/* ok		*/
608 	.setsockopt	   = sock_common_setsockopt,	/* ok		*/
609 	.getsockopt	   = sock_common_getsockopt,	/* ok		*/
610 	.sendmsg	   = inet_sendmsg,		/* ok		*/
611 	.recvmsg	   = inet_recvmsg,		/* ok		*/
612 	.mmap		   = sock_no_mmap,
613 	.sendpage	   = sock_no_sendpage,
614 	.set_peek_off	   = sk_set_peek_off,
615 #ifdef CONFIG_COMPAT
616 	.compat_setsockopt = compat_sock_common_setsockopt,
617 	.compat_getsockopt = compat_sock_common_getsockopt,
618 #endif
619 };
620 
621 static const struct net_proto_family inet6_family_ops = {
622 	.family = PF_INET6,
623 	.create = inet6_create,
624 	.owner	= THIS_MODULE,
625 };
626 
627 int inet6_register_protosw(struct inet_protosw *p)
628 {
629 	struct list_head *lh;
630 	struct inet_protosw *answer;
631 	struct list_head *last_perm;
632 	int protocol = p->protocol;
633 	int ret;
634 
635 	spin_lock_bh(&inetsw6_lock);
636 
637 	ret = -EINVAL;
638 	if (p->type >= SOCK_MAX)
639 		goto out_illegal;
640 
641 	/* If we are trying to override a permanent protocol, bail. */
642 	answer = NULL;
643 	ret = -EPERM;
644 	last_perm = &inetsw6[p->type];
645 	list_for_each(lh, &inetsw6[p->type]) {
646 		answer = list_entry(lh, struct inet_protosw, list);
647 
648 		/* Check only the non-wild match. */
649 		if (INET_PROTOSW_PERMANENT & answer->flags) {
650 			if (protocol == answer->protocol)
651 				break;
652 			last_perm = lh;
653 		}
654 
655 		answer = NULL;
656 	}
657 	if (answer)
658 		goto out_permanent;
659 
660 	/* Add the new entry after the last permanent entry if any, so that
661 	 * the new entry does not override a permanent entry when matched with
662 	 * a wild-card protocol. But it is allowed to override any existing
663 	 * non-permanent entry.  This means that when we remove this entry, the
664 	 * system automatically returns to the old behavior.
665 	 */
666 	list_add_rcu(&p->list, last_perm);
667 	ret = 0;
668 out:
669 	spin_unlock_bh(&inetsw6_lock);
670 	return ret;
671 
672 out_permanent:
673 	pr_err("Attempt to override permanent protocol %d\n", protocol);
674 	goto out;
675 
676 out_illegal:
677 	pr_err("Ignoring attempt to register invalid socket type %d\n",
678 	       p->type);
679 	goto out;
680 }
681 EXPORT_SYMBOL(inet6_register_protosw);
682 
683 void
684 inet6_unregister_protosw(struct inet_protosw *p)
685 {
686 	if (INET_PROTOSW_PERMANENT & p->flags) {
687 		pr_err("Attempt to unregister permanent protocol %d\n",
688 		       p->protocol);
689 	} else {
690 		spin_lock_bh(&inetsw6_lock);
691 		list_del_rcu(&p->list);
692 		spin_unlock_bh(&inetsw6_lock);
693 
694 		synchronize_net();
695 	}
696 }
697 EXPORT_SYMBOL(inet6_unregister_protosw);
698 
699 int inet6_sk_rebuild_header(struct sock *sk)
700 {
701 	struct ipv6_pinfo *np = inet6_sk(sk);
702 	struct dst_entry *dst;
703 
704 	dst = __sk_dst_check(sk, np->dst_cookie);
705 
706 	if (!dst) {
707 		struct inet_sock *inet = inet_sk(sk);
708 		struct in6_addr *final_p, final;
709 		struct flowi6 fl6;
710 
711 		memset(&fl6, 0, sizeof(fl6));
712 		fl6.flowi6_proto = sk->sk_protocol;
713 		fl6.daddr = sk->sk_v6_daddr;
714 		fl6.saddr = np->saddr;
715 		fl6.flowlabel = np->flow_label;
716 		fl6.flowi6_oif = sk->sk_bound_dev_if;
717 		fl6.flowi6_mark = sk->sk_mark;
718 		fl6.fl6_dport = inet->inet_dport;
719 		fl6.fl6_sport = inet->inet_sport;
720 		fl6.flowi6_uid = sk->sk_uid;
721 		security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
722 
723 		rcu_read_lock();
724 		final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt),
725 					 &final);
726 		rcu_read_unlock();
727 
728 		dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
729 		if (IS_ERR(dst)) {
730 			sk->sk_route_caps = 0;
731 			sk->sk_err_soft = -PTR_ERR(dst);
732 			return PTR_ERR(dst);
733 		}
734 
735 		ip6_dst_store(sk, dst, NULL, NULL);
736 	}
737 
738 	return 0;
739 }
740 EXPORT_SYMBOL_GPL(inet6_sk_rebuild_header);
741 
742 bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb,
743 		       const struct inet6_skb_parm *opt)
744 {
745 	const struct ipv6_pinfo *np = inet6_sk(sk);
746 
747 	if (np->rxopt.all) {
748 		if (((opt->flags & IP6SKB_HOPBYHOP) &&
749 		     (np->rxopt.bits.hopopts || np->rxopt.bits.ohopopts)) ||
750 		    (ip6_flowinfo((struct ipv6hdr *) skb_network_header(skb)) &&
751 		     np->rxopt.bits.rxflow) ||
752 		    (opt->srcrt && (np->rxopt.bits.srcrt ||
753 		     np->rxopt.bits.osrcrt)) ||
754 		    ((opt->dst1 || opt->dst0) &&
755 		     (np->rxopt.bits.dstopts || np->rxopt.bits.odstopts)))
756 			return true;
757 	}
758 	return false;
759 }
760 EXPORT_SYMBOL_GPL(ipv6_opt_accepted);
761 
762 static struct packet_type ipv6_packet_type __read_mostly = {
763 	.type = cpu_to_be16(ETH_P_IPV6),
764 	.func = ipv6_rcv,
765 	.list_func = ipv6_list_rcv,
766 };
767 
768 static int __init ipv6_packet_init(void)
769 {
770 	dev_add_pack(&ipv6_packet_type);
771 	return 0;
772 }
773 
774 static void ipv6_packet_cleanup(void)
775 {
776 	dev_remove_pack(&ipv6_packet_type);
777 }
778 
779 static int __net_init ipv6_init_mibs(struct net *net)
780 {
781 	int i;
782 
783 	net->mib.udp_stats_in6 = alloc_percpu(struct udp_mib);
784 	if (!net->mib.udp_stats_in6)
785 		return -ENOMEM;
786 	net->mib.udplite_stats_in6 = alloc_percpu(struct udp_mib);
787 	if (!net->mib.udplite_stats_in6)
788 		goto err_udplite_mib;
789 	net->mib.ipv6_statistics = alloc_percpu(struct ipstats_mib);
790 	if (!net->mib.ipv6_statistics)
791 		goto err_ip_mib;
792 
793 	for_each_possible_cpu(i) {
794 		struct ipstats_mib *af_inet6_stats;
795 		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics, i);
796 		u64_stats_init(&af_inet6_stats->syncp);
797 	}
798 
799 
800 	net->mib.icmpv6_statistics = alloc_percpu(struct icmpv6_mib);
801 	if (!net->mib.icmpv6_statistics)
802 		goto err_icmp_mib;
803 	net->mib.icmpv6msg_statistics = kzalloc(sizeof(struct icmpv6msg_mib),
804 						GFP_KERNEL);
805 	if (!net->mib.icmpv6msg_statistics)
806 		goto err_icmpmsg_mib;
807 	return 0;
808 
809 err_icmpmsg_mib:
810 	free_percpu(net->mib.icmpv6_statistics);
811 err_icmp_mib:
812 	free_percpu(net->mib.ipv6_statistics);
813 err_ip_mib:
814 	free_percpu(net->mib.udplite_stats_in6);
815 err_udplite_mib:
816 	free_percpu(net->mib.udp_stats_in6);
817 	return -ENOMEM;
818 }
819 
820 static void ipv6_cleanup_mibs(struct net *net)
821 {
822 	free_percpu(net->mib.udp_stats_in6);
823 	free_percpu(net->mib.udplite_stats_in6);
824 	free_percpu(net->mib.ipv6_statistics);
825 	free_percpu(net->mib.icmpv6_statistics);
826 	kfree(net->mib.icmpv6msg_statistics);
827 }
828 
829 static int __net_init inet6_net_init(struct net *net)
830 {
831 	int err = 0;
832 
833 	net->ipv6.sysctl.bindv6only = 0;
834 	net->ipv6.sysctl.icmpv6_time = 1*HZ;
835 	net->ipv6.sysctl.icmpv6_echo_ignore_all = 0;
836 	net->ipv6.sysctl.flowlabel_consistency = 1;
837 	net->ipv6.sysctl.auto_flowlabels = IP6_DEFAULT_AUTO_FLOW_LABELS;
838 	net->ipv6.sysctl.idgen_retries = 3;
839 	net->ipv6.sysctl.idgen_delay = 1 * HZ;
840 	net->ipv6.sysctl.flowlabel_state_ranges = 0;
841 	net->ipv6.sysctl.max_dst_opts_cnt = IP6_DEFAULT_MAX_DST_OPTS_CNT;
842 	net->ipv6.sysctl.max_hbh_opts_cnt = IP6_DEFAULT_MAX_HBH_OPTS_CNT;
843 	net->ipv6.sysctl.max_dst_opts_len = IP6_DEFAULT_MAX_DST_OPTS_LEN;
844 	net->ipv6.sysctl.max_hbh_opts_len = IP6_DEFAULT_MAX_HBH_OPTS_LEN;
845 	atomic_set(&net->ipv6.fib6_sernum, 1);
846 
847 	err = ipv6_init_mibs(net);
848 	if (err)
849 		return err;
850 #ifdef CONFIG_PROC_FS
851 	err = udp6_proc_init(net);
852 	if (err)
853 		goto out;
854 	err = tcp6_proc_init(net);
855 	if (err)
856 		goto proc_tcp6_fail;
857 	err = ac6_proc_init(net);
858 	if (err)
859 		goto proc_ac6_fail;
860 #endif
861 	return err;
862 
863 #ifdef CONFIG_PROC_FS
864 proc_ac6_fail:
865 	tcp6_proc_exit(net);
866 proc_tcp6_fail:
867 	udp6_proc_exit(net);
868 out:
869 	ipv6_cleanup_mibs(net);
870 	return err;
871 #endif
872 }
873 
874 static void __net_exit inet6_net_exit(struct net *net)
875 {
876 #ifdef CONFIG_PROC_FS
877 	udp6_proc_exit(net);
878 	tcp6_proc_exit(net);
879 	ac6_proc_exit(net);
880 #endif
881 	ipv6_cleanup_mibs(net);
882 }
883 
884 static struct pernet_operations inet6_net_ops = {
885 	.init = inet6_net_init,
886 	.exit = inet6_net_exit,
887 };
888 
889 static const struct ipv6_stub ipv6_stub_impl = {
890 	.ipv6_sock_mc_join = ipv6_sock_mc_join,
891 	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
892 	.ipv6_dst_lookup   = ip6_dst_lookup,
893 	.fib6_get_table	   = fib6_get_table,
894 	.fib6_table_lookup = fib6_table_lookup,
895 	.fib6_lookup       = fib6_lookup,
896 	.fib6_multipath_select = fib6_multipath_select,
897 	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
898 	.udpv6_encap_enable = udpv6_encap_enable,
899 	.ndisc_send_na = ndisc_send_na,
900 	.nd_tbl	= &nd_tbl,
901 };
902 
903 static const struct ipv6_bpf_stub ipv6_bpf_stub_impl = {
904 	.inet6_bind = __inet6_bind,
905 };
906 
907 static int __init inet6_init(void)
908 {
909 	struct list_head *r;
910 	int err = 0;
911 
912 	sock_skb_cb_check_size(sizeof(struct inet6_skb_parm));
913 
914 	/* Register the socket-side information for inet6_create.  */
915 	for (r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
916 		INIT_LIST_HEAD(r);
917 
918 	if (disable_ipv6_mod) {
919 		pr_info("Loaded, but administratively disabled, reboot required to enable\n");
920 		goto out;
921 	}
922 
923 	err = proto_register(&tcpv6_prot, 1);
924 	if (err)
925 		goto out;
926 
927 	err = proto_register(&udpv6_prot, 1);
928 	if (err)
929 		goto out_unregister_tcp_proto;
930 
931 	err = proto_register(&udplitev6_prot, 1);
932 	if (err)
933 		goto out_unregister_udp_proto;
934 
935 	err = proto_register(&rawv6_prot, 1);
936 	if (err)
937 		goto out_unregister_udplite_proto;
938 
939 	err = proto_register(&pingv6_prot, 1);
940 	if (err)
941 		goto out_unregister_ping_proto;
942 
943 	/* We MUST register RAW sockets before we create the ICMP6,
944 	 * IGMP6, or NDISC control sockets.
945 	 */
946 	err = rawv6_init();
947 	if (err)
948 		goto out_unregister_raw_proto;
949 
950 	/* Register the family here so that the init calls below will
951 	 * be able to create sockets. (?? is this dangerous ??)
952 	 */
953 	err = sock_register(&inet6_family_ops);
954 	if (err)
955 		goto out_sock_register_fail;
956 
957 	/*
958 	 *	ipngwg API draft makes clear that the correct semantics
959 	 *	for TCP and UDP is to consider one TCP and UDP instance
960 	 *	in a host available by both INET and INET6 APIs and
961 	 *	able to communicate via both network protocols.
962 	 */
963 
964 	err = register_pernet_subsys(&inet6_net_ops);
965 	if (err)
966 		goto register_pernet_fail;
967 	err = ip6_mr_init();
968 	if (err)
969 		goto ipmr_fail;
970 	err = icmpv6_init();
971 	if (err)
972 		goto icmp_fail;
973 	err = ndisc_init();
974 	if (err)
975 		goto ndisc_fail;
976 	err = igmp6_init();
977 	if (err)
978 		goto igmp_fail;
979 
980 	err = ipv6_netfilter_init();
981 	if (err)
982 		goto netfilter_fail;
983 	/* Create /proc/foo6 entries. */
984 #ifdef CONFIG_PROC_FS
985 	err = -ENOMEM;
986 	if (raw6_proc_init())
987 		goto proc_raw6_fail;
988 	if (udplite6_proc_init())
989 		goto proc_udplite6_fail;
990 	if (ipv6_misc_proc_init())
991 		goto proc_misc6_fail;
992 	if (if6_proc_init())
993 		goto proc_if6_fail;
994 #endif
995 	err = ip6_route_init();
996 	if (err)
997 		goto ip6_route_fail;
998 	err = ndisc_late_init();
999 	if (err)
1000 		goto ndisc_late_fail;
1001 	err = ip6_flowlabel_init();
1002 	if (err)
1003 		goto ip6_flowlabel_fail;
1004 	err = addrconf_init();
1005 	if (err)
1006 		goto addrconf_fail;
1007 
1008 	/* Init v6 extension headers. */
1009 	err = ipv6_exthdrs_init();
1010 	if (err)
1011 		goto ipv6_exthdrs_fail;
1012 
1013 	err = ipv6_frag_init();
1014 	if (err)
1015 		goto ipv6_frag_fail;
1016 
1017 	/* Init v6 transport protocols. */
1018 	err = udpv6_init();
1019 	if (err)
1020 		goto udpv6_fail;
1021 
1022 	err = udplitev6_init();
1023 	if (err)
1024 		goto udplitev6_fail;
1025 
1026 	err = udpv6_offload_init();
1027 	if (err)
1028 		goto udpv6_offload_fail;
1029 
1030 	err = tcpv6_init();
1031 	if (err)
1032 		goto tcpv6_fail;
1033 
1034 	err = ipv6_packet_init();
1035 	if (err)
1036 		goto ipv6_packet_fail;
1037 
1038 	err = pingv6_init();
1039 	if (err)
1040 		goto pingv6_fail;
1041 
1042 	err = calipso_init();
1043 	if (err)
1044 		goto calipso_fail;
1045 
1046 	err = seg6_init();
1047 	if (err)
1048 		goto seg6_fail;
1049 
1050 	err = igmp6_late_init();
1051 	if (err)
1052 		goto igmp6_late_err;
1053 
1054 #ifdef CONFIG_SYSCTL
1055 	err = ipv6_sysctl_register();
1056 	if (err)
1057 		goto sysctl_fail;
1058 #endif
1059 
1060 	/* ensure that ipv6 stubs are visible only after ipv6 is ready */
1061 	wmb();
1062 	ipv6_stub = &ipv6_stub_impl;
1063 	ipv6_bpf_stub = &ipv6_bpf_stub_impl;
1064 out:
1065 	return err;
1066 
1067 #ifdef CONFIG_SYSCTL
1068 sysctl_fail:
1069 	igmp6_late_cleanup();
1070 #endif
1071 igmp6_late_err:
1072 	seg6_exit();
1073 seg6_fail:
1074 	calipso_exit();
1075 calipso_fail:
1076 	pingv6_exit();
1077 pingv6_fail:
1078 	ipv6_packet_cleanup();
1079 ipv6_packet_fail:
1080 	tcpv6_exit();
1081 tcpv6_fail:
1082 	udpv6_offload_exit();
1083 udpv6_offload_fail:
1084 	udplitev6_exit();
1085 udplitev6_fail:
1086 	udpv6_exit();
1087 udpv6_fail:
1088 	ipv6_frag_exit();
1089 ipv6_frag_fail:
1090 	ipv6_exthdrs_exit();
1091 ipv6_exthdrs_fail:
1092 	addrconf_cleanup();
1093 addrconf_fail:
1094 	ip6_flowlabel_cleanup();
1095 ip6_flowlabel_fail:
1096 	ndisc_late_cleanup();
1097 ndisc_late_fail:
1098 	ip6_route_cleanup();
1099 ip6_route_fail:
1100 #ifdef CONFIG_PROC_FS
1101 	if6_proc_exit();
1102 proc_if6_fail:
1103 	ipv6_misc_proc_exit();
1104 proc_misc6_fail:
1105 	udplite6_proc_exit();
1106 proc_udplite6_fail:
1107 	raw6_proc_exit();
1108 proc_raw6_fail:
1109 #endif
1110 	ipv6_netfilter_fini();
1111 netfilter_fail:
1112 	igmp6_cleanup();
1113 igmp_fail:
1114 	ndisc_cleanup();
1115 ndisc_fail:
1116 	ip6_mr_cleanup();
1117 icmp_fail:
1118 	unregister_pernet_subsys(&inet6_net_ops);
1119 ipmr_fail:
1120 	icmpv6_cleanup();
1121 register_pernet_fail:
1122 	sock_unregister(PF_INET6);
1123 	rtnl_unregister_all(PF_INET6);
1124 out_sock_register_fail:
1125 	rawv6_exit();
1126 out_unregister_ping_proto:
1127 	proto_unregister(&pingv6_prot);
1128 out_unregister_raw_proto:
1129 	proto_unregister(&rawv6_prot);
1130 out_unregister_udplite_proto:
1131 	proto_unregister(&udplitev6_prot);
1132 out_unregister_udp_proto:
1133 	proto_unregister(&udpv6_prot);
1134 out_unregister_tcp_proto:
1135 	proto_unregister(&tcpv6_prot);
1136 	goto out;
1137 }
1138 module_init(inet6_init);
1139 
1140 MODULE_ALIAS_NETPROTO(PF_INET6);
1141