xref: /linux/net/sctp/protocol.c (revision 0ad9617c78acbc71373fb341a6f75d4012b01d69)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001 Intel Corp.
7  * Copyright (c) 2001 Nokia, Inc.
8  * Copyright (c) 2001 La Monte H.P. Yarroll
9  *
10  * This file is part of the SCTP kernel implementation
11  *
12  * Initialization/cleanup for SCTP protocol support.
13  *
14  * Please send any bug reports or fixes you make to the
15  * email address(es):
16  *    lksctp developers <linux-sctp@vger.kernel.org>
17  *
18  * Written or modified by:
19  *    La Monte H.P. Yarroll <piggy@acm.org>
20  *    Karl Knutson <karl@athena.chicago.il.us>
21  *    Jon Grimm <jgrimm@us.ibm.com>
22  *    Sridhar Samudrala <sri@us.ibm.com>
23  *    Daisy Chang <daisyc@us.ibm.com>
24  *    Ardelle Fan <ardelle.fan@intel.com>
25  */
26 
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28 
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/netdevice.h>
32 #include <linux/inetdevice.h>
33 #include <linux/seq_file.h>
34 #include <linux/memblock.h>
35 #include <linux/highmem.h>
36 #include <linux/slab.h>
37 #include <net/net_namespace.h>
38 #include <net/protocol.h>
39 #include <net/ip.h>
40 #include <net/ipv6.h>
41 #include <net/route.h>
42 #include <net/sctp/sctp.h>
43 #include <net/addrconf.h>
44 #include <net/inet_common.h>
45 #include <net/inet_ecn.h>
46 #include <net/inet_sock.h>
47 #include <net/udp_tunnel.h>
48 #include <net/inet_dscp.h>
49 
50 #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024)
51 
52 /* Global data structures. */
53 struct sctp_globals sctp_globals __read_mostly;
54 
55 struct idr sctp_assocs_id;
56 DEFINE_SPINLOCK(sctp_assocs_id_lock);
57 
58 static struct sctp_pf *sctp_pf_inet6_specific;
59 static struct sctp_pf *sctp_pf_inet_specific;
60 static struct sctp_af *sctp_af_v4_specific;
61 static struct sctp_af *sctp_af_v6_specific;
62 
63 struct kmem_cache *sctp_chunk_cachep __read_mostly;
64 struct kmem_cache *sctp_bucket_cachep __read_mostly;
65 
66 long sysctl_sctp_mem[3];
67 int sysctl_sctp_rmem[3];
68 int sysctl_sctp_wmem[3];
69 
70 /* Private helper to extract ipv4 address and stash them in
71  * the protocol structure.
72  */
73 static void sctp_v4_copy_addrlist(struct list_head *addrlist,
74 				  struct net_device *dev)
75 {
76 	struct in_device *in_dev;
77 	struct in_ifaddr *ifa;
78 	struct sctp_sockaddr_entry *addr;
79 
80 	rcu_read_lock();
81 	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
82 		rcu_read_unlock();
83 		return;
84 	}
85 
86 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
87 		/* Add the address to the local list.  */
88 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
89 		if (addr) {
90 			addr->a.v4.sin_family = AF_INET;
91 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
92 			addr->valid = 1;
93 			INIT_LIST_HEAD(&addr->list);
94 			list_add_tail(&addr->list, addrlist);
95 		}
96 	}
97 
98 	rcu_read_unlock();
99 }
100 
101 /* Extract our IP addresses from the system and stash them in the
102  * protocol structure.
103  */
104 static void sctp_get_local_addr_list(struct net *net)
105 {
106 	struct net_device *dev;
107 	struct list_head *pos;
108 	struct sctp_af *af;
109 
110 	rcu_read_lock();
111 	for_each_netdev_rcu(net, dev) {
112 		list_for_each(pos, &sctp_address_families) {
113 			af = list_entry(pos, struct sctp_af, list);
114 			af->copy_addrlist(&net->sctp.local_addr_list, dev);
115 		}
116 	}
117 	rcu_read_unlock();
118 }
119 
120 /* Free the existing local addresses.  */
121 static void sctp_free_local_addr_list(struct net *net)
122 {
123 	struct sctp_sockaddr_entry *addr;
124 	struct list_head *pos, *temp;
125 
126 	list_for_each_safe(pos, temp, &net->sctp.local_addr_list) {
127 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
128 		list_del(pos);
129 		kfree(addr);
130 	}
131 }
132 
133 /* Copy the local addresses which are valid for 'scope' into 'bp'.  */
134 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
135 			      enum sctp_scope scope, gfp_t gfp, int copy_flags)
136 {
137 	struct sctp_sockaddr_entry *addr;
138 	union sctp_addr laddr;
139 	int error = 0;
140 
141 	rcu_read_lock();
142 	list_for_each_entry_rcu(addr, &net->sctp.local_addr_list, list) {
143 		if (!addr->valid)
144 			continue;
145 		if (!sctp_in_scope(net, &addr->a, scope))
146 			continue;
147 
148 		/* Now that the address is in scope, check to see if
149 		 * the address type is really supported by the local
150 		 * sock as well as the remote peer.
151 		 */
152 		if (addr->a.sa.sa_family == AF_INET &&
153 		    (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
154 		     !(copy_flags & SCTP_ADDR4_PEERSUPP)))
155 			continue;
156 		if (addr->a.sa.sa_family == AF_INET6 &&
157 		    (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
158 		     !(copy_flags & SCTP_ADDR6_PEERSUPP)))
159 			continue;
160 
161 		laddr = addr->a;
162 		/* also works for setting ipv6 address port */
163 		laddr.v4.sin_port = htons(bp->port);
164 		if (sctp_bind_addr_state(bp, &laddr) != -1)
165 			continue;
166 
167 		error = sctp_add_bind_addr(bp, &addr->a, sizeof(addr->a),
168 					   SCTP_ADDR_SRC, GFP_ATOMIC);
169 		if (error)
170 			break;
171 	}
172 
173 	rcu_read_unlock();
174 	return error;
175 }
176 
177 /* Copy over any ip options */
178 static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
179 {
180 	struct inet_sock *newinet, *inet = inet_sk(sk);
181 	struct ip_options_rcu *inet_opt, *newopt = NULL;
182 
183 	newinet = inet_sk(newsk);
184 
185 	rcu_read_lock();
186 	inet_opt = rcu_dereference(inet->inet_opt);
187 	if (inet_opt) {
188 		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
189 				      inet_opt->opt.optlen, GFP_ATOMIC);
190 		if (newopt)
191 			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
192 			       inet_opt->opt.optlen);
193 		else
194 			pr_err("%s: Failed to copy ip options\n", __func__);
195 	}
196 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
197 	rcu_read_unlock();
198 }
199 
200 /* Account for the IP options */
201 static int sctp_v4_ip_options_len(struct sock *sk)
202 {
203 	struct inet_sock *inet = inet_sk(sk);
204 	struct ip_options_rcu *inet_opt;
205 	int len = 0;
206 
207 	rcu_read_lock();
208 	inet_opt = rcu_dereference(inet->inet_opt);
209 	if (inet_opt)
210 		len = inet_opt->opt.optlen;
211 
212 	rcu_read_unlock();
213 	return len;
214 }
215 
216 /* Initialize a sctp_addr from in incoming skb.  */
217 static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
218 			     int is_saddr)
219 {
220 	/* Always called on head skb, so this is safe */
221 	struct sctphdr *sh = sctp_hdr(skb);
222 	struct sockaddr_in *sa = &addr->v4;
223 
224 	addr->v4.sin_family = AF_INET;
225 
226 	if (is_saddr) {
227 		sa->sin_port = sh->source;
228 		sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
229 	} else {
230 		sa->sin_port = sh->dest;
231 		sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
232 	}
233 	memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
234 }
235 
236 /* Initialize an sctp_addr from a socket. */
237 static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
238 {
239 	addr->v4.sin_family = AF_INET;
240 	addr->v4.sin_port = 0;
241 	addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
242 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
243 }
244 
245 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
246 static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
247 {
248 	inet_sk(sk)->inet_rcv_saddr = addr->v4.sin_addr.s_addr;
249 }
250 
251 /* Initialize sk->sk_daddr from sctp_addr. */
252 static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
253 {
254 	inet_sk(sk)->inet_daddr = addr->v4.sin_addr.s_addr;
255 }
256 
257 /* Initialize a sctp_addr from an address parameter. */
258 static bool sctp_v4_from_addr_param(union sctp_addr *addr,
259 				    union sctp_addr_param *param,
260 				    __be16 port, int iif)
261 {
262 	if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
263 		return false;
264 
265 	addr->v4.sin_family = AF_INET;
266 	addr->v4.sin_port = port;
267 	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
268 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
269 
270 	return true;
271 }
272 
273 /* Initialize an address parameter from a sctp_addr and return the length
274  * of the address parameter.
275  */
276 static int sctp_v4_to_addr_param(const union sctp_addr *addr,
277 				 union sctp_addr_param *param)
278 {
279 	int length = sizeof(struct sctp_ipv4addr_param);
280 
281 	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
282 	param->v4.param_hdr.length = htons(length);
283 	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;
284 
285 	return length;
286 }
287 
288 /* Initialize a sctp_addr from a dst_entry. */
289 static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct flowi4 *fl4,
290 			      __be16 port)
291 {
292 	saddr->v4.sin_family = AF_INET;
293 	saddr->v4.sin_port = port;
294 	saddr->v4.sin_addr.s_addr = fl4->saddr;
295 	memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
296 }
297 
298 /* Compare two addresses exactly. */
299 static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
300 			    const union sctp_addr *addr2)
301 {
302 	if (addr1->sa.sa_family != addr2->sa.sa_family)
303 		return 0;
304 	if (addr1->v4.sin_port != addr2->v4.sin_port)
305 		return 0;
306 	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
307 		return 0;
308 
309 	return 1;
310 }
311 
312 /* Initialize addr struct to INADDR_ANY. */
313 static void sctp_v4_inaddr_any(union sctp_addr *addr, __be16 port)
314 {
315 	addr->v4.sin_family = AF_INET;
316 	addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
317 	addr->v4.sin_port = port;
318 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
319 }
320 
321 /* Is this a wildcard address? */
322 static int sctp_v4_is_any(const union sctp_addr *addr)
323 {
324 	return htonl(INADDR_ANY) == addr->v4.sin_addr.s_addr;
325 }
326 
327 /* This function checks if the address is a valid address to be used for
328  * SCTP binding.
329  *
330  * Output:
331  * Return 0 - If the address is a non-unicast or an illegal address.
332  * Return 1 - If the address is a unicast.
333  */
334 static int sctp_v4_addr_valid(union sctp_addr *addr,
335 			      struct sctp_sock *sp,
336 			      const struct sk_buff *skb)
337 {
338 	/* IPv4 addresses not allowed */
339 	if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
340 		return 0;
341 
342 	/* Is this a non-unicast address or a unusable SCTP address? */
343 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr))
344 		return 0;
345 
346 	/* Is this a broadcast address? */
347 	if (skb && skb_rtable(skb)->rt_flags & RTCF_BROADCAST)
348 		return 0;
349 
350 	return 1;
351 }
352 
353 /* Should this be available for binding?   */
354 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
355 {
356 	struct sock *sk = &sp->inet.sk;
357 	struct net *net = sock_net(sk);
358 	int tb_id = RT_TABLE_LOCAL;
359 	int ret;
360 
361 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
362 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
363 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
364 	   ret != RTN_LOCAL &&
365 	   !inet_test_bit(FREEBIND, sk) &&
366 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
367 		return 0;
368 
369 	if (ipv6_only_sock(sctp_opt2sk(sp)))
370 		return 0;
371 
372 	return 1;
373 }
374 
375 /* Checking the loopback, private and other address scopes as defined in
376  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
377  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
378  *
379  * Level 0 - unusable SCTP addresses
380  * Level 1 - loopback address
381  * Level 2 - link-local addresses
382  * Level 3 - private addresses.
383  * Level 4 - global addresses
384  * For INIT and INIT-ACK address list, let L be the level of
385  * requested destination address, sender and receiver
386  * SHOULD include all of its addresses with level greater
387  * than or equal to L.
388  *
389  * IPv4 scoping can be controlled through sysctl option
390  * net.sctp.addr_scope_policy
391  */
392 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
393 {
394 	enum sctp_scope retval;
395 
396 	/* Check for unusable SCTP addresses. */
397 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
398 		retval =  SCTP_SCOPE_UNUSABLE;
399 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
400 		retval = SCTP_SCOPE_LOOPBACK;
401 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
402 		retval = SCTP_SCOPE_LINK;
403 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
404 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
405 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
406 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
407 		retval = SCTP_SCOPE_PRIVATE;
408 	} else {
409 		retval = SCTP_SCOPE_GLOBAL;
410 	}
411 
412 	return retval;
413 }
414 
415 /* Returns a valid dst cache entry for the given source and destination ip
416  * addresses. If an association is passed, trys to get a dst entry with a
417  * source address that matches an address in the bind address list.
418  */
419 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
420 				struct flowi *fl, struct sock *sk)
421 {
422 	struct sctp_association *asoc = t->asoc;
423 	struct rtable *rt;
424 	struct flowi _fl;
425 	struct flowi4 *fl4 = &_fl.u.ip4;
426 	struct sctp_bind_addr *bp;
427 	struct sctp_sockaddr_entry *laddr;
428 	struct dst_entry *dst = NULL;
429 	union sctp_addr *daddr = &t->ipaddr;
430 	union sctp_addr dst_saddr;
431 	dscp_t dscp;
432 
433 	if (t->dscp & SCTP_DSCP_SET_MASK)
434 		dscp = inet_dsfield_to_dscp(t->dscp);
435 	else
436 		dscp = inet_sk_dscp(inet_sk(sk));
437 
438 	memset(&_fl, 0x0, sizeof(_fl));
439 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
440 	fl4->fl4_dport = daddr->v4.sin_port;
441 	fl4->flowi4_proto = IPPROTO_SCTP;
442 	if (asoc) {
443 		fl4->flowi4_tos = inet_dscp_to_dsfield(dscp);
444 		fl4->flowi4_scope = ip_sock_rt_scope(asoc->base.sk);
445 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
446 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
447 	}
448 	if (saddr) {
449 		fl4->saddr = saddr->v4.sin_addr.s_addr;
450 		if (!fl4->fl4_sport)
451 			fl4->fl4_sport = saddr->v4.sin_port;
452 	}
453 
454 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
455 		 &fl4->saddr);
456 
457 	rt = ip_route_output_key(sock_net(sk), fl4);
458 	if (!IS_ERR(rt)) {
459 		dst = &rt->dst;
460 		t->dst = dst;
461 		memcpy(fl, &_fl, sizeof(_fl));
462 	}
463 
464 	/* If there is no association or if a source address is passed, no
465 	 * more validation is required.
466 	 */
467 	if (!asoc || saddr)
468 		goto out;
469 
470 	bp = &asoc->base.bind_addr;
471 
472 	if (dst) {
473 		/* Walk through the bind address list and look for a bind
474 		 * address that matches the source address of the returned dst.
475 		 */
476 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
477 		rcu_read_lock();
478 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
479 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
480 			    (laddr->state != SCTP_ADDR_SRC &&
481 			    !asoc->src_out_of_asoc_ok))
482 				continue;
483 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
484 				goto out_unlock;
485 		}
486 		rcu_read_unlock();
487 
488 		/* None of the bound addresses match the source address of the
489 		 * dst. So release it.
490 		 */
491 		dst_release(dst);
492 		dst = NULL;
493 	}
494 
495 	/* Walk through the bind address list and try to get a dst that
496 	 * matches a bind address as the source address.
497 	 */
498 	rcu_read_lock();
499 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
500 		struct net_device *odev;
501 
502 		if (!laddr->valid)
503 			continue;
504 		if (laddr->state != SCTP_ADDR_SRC ||
505 		    AF_INET != laddr->a.sa.sa_family)
506 			continue;
507 
508 		fl4->fl4_sport = laddr->a.v4.sin_port;
509 		flowi4_update_output(fl4, asoc->base.sk->sk_bound_dev_if,
510 				     daddr->v4.sin_addr.s_addr,
511 				     laddr->a.v4.sin_addr.s_addr);
512 
513 		rt = ip_route_output_key(sock_net(sk), fl4);
514 		if (IS_ERR(rt))
515 			continue;
516 
517 		/* Ensure the src address belongs to the output
518 		 * interface.
519 		 */
520 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
521 				     false);
522 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
523 			if (!dst) {
524 				dst = &rt->dst;
525 				t->dst = dst;
526 				memcpy(fl, &_fl, sizeof(_fl));
527 			} else {
528 				dst_release(&rt->dst);
529 			}
530 			continue;
531 		}
532 
533 		dst_release(dst);
534 		dst = &rt->dst;
535 		t->dst = dst;
536 		memcpy(fl, &_fl, sizeof(_fl));
537 		break;
538 	}
539 
540 out_unlock:
541 	rcu_read_unlock();
542 out:
543 	if (dst) {
544 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
545 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
546 	} else {
547 		t->dst = NULL;
548 		pr_debug("no route\n");
549 	}
550 }
551 
552 /* For v4, the source address is cached in the route entry(dst). So no need
553  * to cache it separately and hence this is an empty routine.
554  */
555 static void sctp_v4_get_saddr(struct sctp_sock *sk,
556 			      struct sctp_transport *t,
557 			      struct flowi *fl)
558 {
559 	union sctp_addr *saddr = &t->saddr;
560 	struct rtable *rt = dst_rtable(t->dst);
561 
562 	if (rt) {
563 		saddr->v4.sin_family = AF_INET;
564 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
565 	}
566 }
567 
568 /* What interface did this skb arrive on? */
569 static int sctp_v4_skb_iif(const struct sk_buff *skb)
570 {
571 	return inet_iif(skb);
572 }
573 
574 static int sctp_v4_skb_sdif(const struct sk_buff *skb)
575 {
576 	return inet_sdif(skb);
577 }
578 
579 /* Was this packet marked by Explicit Congestion Notification? */
580 static int sctp_v4_is_ce(const struct sk_buff *skb)
581 {
582 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
583 }
584 
585 /* Create and initialize a new sk for the socket returned by accept(). */
586 static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
587 					     struct sctp_association *asoc,
588 					     bool kern)
589 {
590 	struct sock *newsk = sk_alloc(sock_net(sk), PF_INET, GFP_KERNEL,
591 			sk->sk_prot, kern);
592 	struct inet_sock *newinet;
593 
594 	if (!newsk)
595 		goto out;
596 
597 	sock_init_data(NULL, newsk);
598 
599 	sctp_copy_sock(newsk, sk, asoc);
600 	sock_reset_flag(newsk, SOCK_ZAPPED);
601 
602 	sctp_v4_copy_ip_options(sk, newsk);
603 
604 	newinet = inet_sk(newsk);
605 
606 	newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
607 
608 	if (newsk->sk_prot->init(newsk)) {
609 		sk_common_release(newsk);
610 		newsk = NULL;
611 	}
612 
613 out:
614 	return newsk;
615 }
616 
617 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
618 {
619 	/* No address mapping for V4 sockets */
620 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
621 	return sizeof(struct sockaddr_in);
622 }
623 
624 /* Dump the v4 addr to the seq file. */
625 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
626 {
627 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
628 }
629 
630 static void sctp_v4_ecn_capable(struct sock *sk)
631 {
632 	INET_ECN_xmit(sk);
633 }
634 
635 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
636 {
637 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
638 	struct sctp_sockaddr_entry *addrw, *temp;
639 	struct sctp_sock *sp;
640 
641 	spin_lock_bh(&net->sctp.addr_wq_lock);
642 
643 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
644 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
645 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
646 			 addrw->state, addrw);
647 
648 #if IS_ENABLED(CONFIG_IPV6)
649 		/* Now we send an ASCONF for each association */
650 		/* Note. we currently don't handle link local IPv6 addressees */
651 		if (addrw->a.sa.sa_family == AF_INET6) {
652 			struct in6_addr *in6;
653 
654 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
655 			    IPV6_ADDR_LINKLOCAL)
656 				goto free_next;
657 
658 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
659 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
660 			    addrw->state == SCTP_ADDR_NEW) {
661 				unsigned long timeo_val;
662 
663 				pr_debug("%s: this is on DAD, trying %d sec "
664 					 "later\n", __func__,
665 					 SCTP_ADDRESS_TICK_DELAY);
666 
667 				timeo_val = jiffies;
668 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
669 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
670 				break;
671 			}
672 		}
673 #endif
674 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
675 			struct sock *sk;
676 
677 			sk = sctp_opt2sk(sp);
678 			/* ignore bound-specific endpoints */
679 			if (!sctp_is_ep_boundall(sk))
680 				continue;
681 			bh_lock_sock(sk);
682 			if (sctp_asconf_mgmt(sp, addrw) < 0)
683 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
684 			bh_unlock_sock(sk);
685 		}
686 #if IS_ENABLED(CONFIG_IPV6)
687 free_next:
688 #endif
689 		list_del(&addrw->list);
690 		kfree(addrw);
691 	}
692 	spin_unlock_bh(&net->sctp.addr_wq_lock);
693 }
694 
695 static void sctp_free_addr_wq(struct net *net)
696 {
697 	struct sctp_sockaddr_entry *addrw;
698 	struct sctp_sockaddr_entry *temp;
699 
700 	spin_lock_bh(&net->sctp.addr_wq_lock);
701 	del_timer(&net->sctp.addr_wq_timer);
702 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
703 		list_del(&addrw->list);
704 		kfree(addrw);
705 	}
706 	spin_unlock_bh(&net->sctp.addr_wq_lock);
707 }
708 
709 /* lookup the entry for the same address in the addr_waitq
710  * sctp_addr_wq MUST be locked
711  */
712 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
713 					struct sctp_sockaddr_entry *addr)
714 {
715 	struct sctp_sockaddr_entry *addrw;
716 
717 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
718 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
719 			continue;
720 		if (addrw->a.sa.sa_family == AF_INET) {
721 			if (addrw->a.v4.sin_addr.s_addr ==
722 			    addr->a.v4.sin_addr.s_addr)
723 				return addrw;
724 		} else if (addrw->a.sa.sa_family == AF_INET6) {
725 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
726 			    &addr->a.v6.sin6_addr))
727 				return addrw;
728 		}
729 	}
730 	return NULL;
731 }
732 
733 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
734 {
735 	struct sctp_sockaddr_entry *addrw;
736 	unsigned long timeo_val;
737 
738 	/* first, we check if an opposite message already exist in the queue.
739 	 * If we found such message, it is removed.
740 	 * This operation is a bit stupid, but the DHCP client attaches the
741 	 * new address after a couple of addition and deletion of that address
742 	 */
743 
744 	spin_lock_bh(&net->sctp.addr_wq_lock);
745 
746 	/* Avoid searching the queue or modifying it if there are no consumers,
747 	 * as it can lead to performance degradation if addresses are modified
748 	 * en-masse.
749 	 *
750 	 * If the queue already contains some events, update it anyway to avoid
751 	 * ugly races between new sessions and new address events.
752 	 */
753 	if (list_empty(&net->sctp.auto_asconf_splist) &&
754 	    list_empty(&net->sctp.addr_waitq)) {
755 		spin_unlock_bh(&net->sctp.addr_wq_lock);
756 		return;
757 	}
758 
759 	/* Offsets existing events in addr_wq */
760 	addrw = sctp_addr_wq_lookup(net, addr);
761 	if (addrw) {
762 		if (addrw->state != cmd) {
763 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
764 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
765 				 &net->sctp.addr_waitq);
766 
767 			list_del(&addrw->list);
768 			kfree(addrw);
769 		}
770 		spin_unlock_bh(&net->sctp.addr_wq_lock);
771 		return;
772 	}
773 
774 	/* OK, we have to add the new address to the wait queue */
775 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
776 	if (addrw == NULL) {
777 		spin_unlock_bh(&net->sctp.addr_wq_lock);
778 		return;
779 	}
780 	addrw->state = cmd;
781 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
782 
783 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
784 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
785 
786 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
787 		timeo_val = jiffies;
788 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
789 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
790 	}
791 	spin_unlock_bh(&net->sctp.addr_wq_lock);
792 }
793 
794 /* Event handler for inet address addition/deletion events.
795  * The sctp_local_addr_list needs to be protocted by a spin lock since
796  * multiple notifiers (say IPv4 and IPv6) may be running at the same
797  * time and thus corrupt the list.
798  * The reader side is protected with RCU.
799  */
800 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
801 			       void *ptr)
802 {
803 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
804 	struct sctp_sockaddr_entry *addr = NULL;
805 	struct sctp_sockaddr_entry *temp;
806 	struct net *net = dev_net(ifa->ifa_dev->dev);
807 	int found = 0;
808 
809 	switch (ev) {
810 	case NETDEV_UP:
811 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
812 		if (addr) {
813 			addr->a.v4.sin_family = AF_INET;
814 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
815 			addr->valid = 1;
816 			spin_lock_bh(&net->sctp.local_addr_lock);
817 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
818 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
819 			spin_unlock_bh(&net->sctp.local_addr_lock);
820 		}
821 		break;
822 	case NETDEV_DOWN:
823 		spin_lock_bh(&net->sctp.local_addr_lock);
824 		list_for_each_entry_safe(addr, temp,
825 					&net->sctp.local_addr_list, list) {
826 			if (addr->a.sa.sa_family == AF_INET &&
827 					addr->a.v4.sin_addr.s_addr ==
828 					ifa->ifa_local) {
829 				found = 1;
830 				addr->valid = 0;
831 				list_del_rcu(&addr->list);
832 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
833 				break;
834 			}
835 		}
836 		spin_unlock_bh(&net->sctp.local_addr_lock);
837 		if (found)
838 			kfree_rcu(addr, rcu);
839 		break;
840 	}
841 
842 	return NOTIFY_DONE;
843 }
844 
845 /*
846  * Initialize the control inode/socket with a control endpoint data
847  * structure.  This endpoint is reserved exclusively for the OOTB processing.
848  */
849 static int sctp_ctl_sock_init(struct net *net)
850 {
851 	int err;
852 	sa_family_t family = PF_INET;
853 
854 	if (sctp_get_pf_specific(PF_INET6))
855 		family = PF_INET6;
856 
857 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
858 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
859 
860 	/* If IPv6 socket could not be created, try the IPv4 socket */
861 	if (err < 0 && family == PF_INET6)
862 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
863 					   SOCK_SEQPACKET, IPPROTO_SCTP,
864 					   net);
865 
866 	if (err < 0) {
867 		pr_err("Failed to create the SCTP control socket\n");
868 		return err;
869 	}
870 	return 0;
871 }
872 
873 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
874 {
875 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
876 
877 	skb_set_transport_header(skb, sizeof(struct udphdr));
878 	sctp_rcv(skb);
879 	return 0;
880 }
881 
882 int sctp_udp_sock_start(struct net *net)
883 {
884 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
885 	struct udp_port_cfg udp_conf = {0};
886 	struct socket *sock;
887 	int err;
888 
889 	udp_conf.family = AF_INET;
890 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
891 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
892 	err = udp_sock_create(net, &udp_conf, &sock);
893 	if (err) {
894 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
895 		return err;
896 	}
897 
898 	tuncfg.encap_type = 1;
899 	tuncfg.encap_rcv = sctp_udp_rcv;
900 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
901 	setup_udp_tunnel_sock(net, sock, &tuncfg);
902 	net->sctp.udp4_sock = sock->sk;
903 
904 #if IS_ENABLED(CONFIG_IPV6)
905 	memset(&udp_conf, 0, sizeof(udp_conf));
906 
907 	udp_conf.family = AF_INET6;
908 	udp_conf.local_ip6 = in6addr_any;
909 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
910 	udp_conf.use_udp6_rx_checksums = true;
911 	udp_conf.ipv6_v6only = true;
912 	err = udp_sock_create(net, &udp_conf, &sock);
913 	if (err) {
914 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
915 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
916 		net->sctp.udp4_sock = NULL;
917 		return err;
918 	}
919 
920 	tuncfg.encap_type = 1;
921 	tuncfg.encap_rcv = sctp_udp_rcv;
922 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
923 	setup_udp_tunnel_sock(net, sock, &tuncfg);
924 	net->sctp.udp6_sock = sock->sk;
925 #endif
926 
927 	return 0;
928 }
929 
930 void sctp_udp_sock_stop(struct net *net)
931 {
932 	if (net->sctp.udp4_sock) {
933 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
934 		net->sctp.udp4_sock = NULL;
935 	}
936 	if (net->sctp.udp6_sock) {
937 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
938 		net->sctp.udp6_sock = NULL;
939 	}
940 }
941 
942 /* Register address family specific functions. */
943 int sctp_register_af(struct sctp_af *af)
944 {
945 	switch (af->sa_family) {
946 	case AF_INET:
947 		if (sctp_af_v4_specific)
948 			return 0;
949 		sctp_af_v4_specific = af;
950 		break;
951 	case AF_INET6:
952 		if (sctp_af_v6_specific)
953 			return 0;
954 		sctp_af_v6_specific = af;
955 		break;
956 	default:
957 		return 0;
958 	}
959 
960 	INIT_LIST_HEAD(&af->list);
961 	list_add_tail(&af->list, &sctp_address_families);
962 	return 1;
963 }
964 
965 /* Get the table of functions for manipulating a particular address
966  * family.
967  */
968 struct sctp_af *sctp_get_af_specific(sa_family_t family)
969 {
970 	switch (family) {
971 	case AF_INET:
972 		return sctp_af_v4_specific;
973 	case AF_INET6:
974 		return sctp_af_v6_specific;
975 	default:
976 		return NULL;
977 	}
978 }
979 
980 /* Common code to initialize a AF_INET msg_name. */
981 static void sctp_inet_msgname(char *msgname, int *addr_len)
982 {
983 	struct sockaddr_in *sin;
984 
985 	sin = (struct sockaddr_in *)msgname;
986 	*addr_len = sizeof(struct sockaddr_in);
987 	sin->sin_family = AF_INET;
988 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
989 }
990 
991 /* Copy the primary address of the peer primary address as the msg_name. */
992 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
993 				    int *addr_len)
994 {
995 	struct sockaddr_in *sin, *sinfrom;
996 
997 	if (msgname) {
998 		struct sctp_association *asoc;
999 
1000 		asoc = event->asoc;
1001 		sctp_inet_msgname(msgname, addr_len);
1002 		sin = (struct sockaddr_in *)msgname;
1003 		sinfrom = &asoc->peer.primary_addr.v4;
1004 		sin->sin_port = htons(asoc->peer.port);
1005 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
1006 	}
1007 }
1008 
1009 /* Initialize and copy out a msgname from an inbound skb. */
1010 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
1011 {
1012 	if (msgname) {
1013 		struct sctphdr *sh = sctp_hdr(skb);
1014 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
1015 
1016 		sctp_inet_msgname(msgname, len);
1017 		sin->sin_port = sh->source;
1018 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1019 	}
1020 }
1021 
1022 /* Do we support this AF? */
1023 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1024 {
1025 	/* PF_INET only supports AF_INET addresses. */
1026 	return AF_INET == family;
1027 }
1028 
1029 /* Address matching with wildcards allowed. */
1030 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1031 			      const union sctp_addr *addr2,
1032 			      struct sctp_sock *opt)
1033 {
1034 	/* PF_INET only supports AF_INET addresses. */
1035 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1036 		return 0;
1037 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1038 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1039 		return 1;
1040 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1041 		return 1;
1042 
1043 	return 0;
1044 }
1045 
1046 /* Verify that provided sockaddr looks bindable.  Common verification has
1047  * already been taken care of.
1048  */
1049 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1050 {
1051 	return sctp_v4_available(addr, opt);
1052 }
1053 
1054 /* Verify that sockaddr looks sendable.  Common verification has already
1055  * been taken care of.
1056  */
1057 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1058 {
1059 	return 1;
1060 }
1061 
1062 /* Fill in Supported Address Type information for INIT and INIT-ACK
1063  * chunks.  Returns number of addresses supported.
1064  */
1065 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1066 				     __be16 *types)
1067 {
1068 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1069 	return 1;
1070 }
1071 
1072 /* Wrapper routine that calls the ip transmit routine. */
1073 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1074 {
1075 	struct dst_entry *dst = dst_clone(t->dst);
1076 	struct flowi4 *fl4 = &t->fl.u.ip4;
1077 	struct sock *sk = skb->sk;
1078 	struct inet_sock *inet = inet_sk(sk);
1079 	__u8 dscp = READ_ONCE(inet->tos);
1080 	__be16 df = 0;
1081 
1082 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1083 		 skb->len, &fl4->saddr, &fl4->daddr);
1084 
1085 	if (t->dscp & SCTP_DSCP_SET_MASK)
1086 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1087 
1088 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1089 							   : IP_PMTUDISC_DONT;
1090 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1091 
1092 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1093 		skb_dst_set(skb, dst);
1094 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1095 	}
1096 
1097 	if (skb_is_gso(skb))
1098 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1099 
1100 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1101 		df = htons(IP_DF);
1102 
1103 	skb->encapsulation = 1;
1104 	skb_reset_inner_mac_header(skb);
1105 	skb_reset_inner_transport_header(skb);
1106 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1107 	udp_tunnel_xmit_skb(dst_rtable(dst), sk, skb, fl4->saddr,
1108 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1109 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1110 	return 0;
1111 }
1112 
1113 static struct sctp_af sctp_af_inet;
1114 
1115 static struct sctp_pf sctp_pf_inet = {
1116 	.event_msgname = sctp_inet_event_msgname,
1117 	.skb_msgname   = sctp_inet_skb_msgname,
1118 	.af_supported  = sctp_inet_af_supported,
1119 	.cmp_addr      = sctp_inet_cmp_addr,
1120 	.bind_verify   = sctp_inet_bind_verify,
1121 	.send_verify   = sctp_inet_send_verify,
1122 	.supported_addrs = sctp_inet_supported_addrs,
1123 	.create_accept_sk = sctp_v4_create_accept_sk,
1124 	.addr_to_user  = sctp_v4_addr_to_user,
1125 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1126 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1127 	.copy_ip_options = sctp_v4_copy_ip_options,
1128 	.af            = &sctp_af_inet
1129 };
1130 
1131 /* Notifier for inetaddr addition/deletion events.  */
1132 static struct notifier_block sctp_inetaddr_notifier = {
1133 	.notifier_call = sctp_inetaddr_event,
1134 };
1135 
1136 /* Socket operations.  */
1137 static const struct proto_ops inet_seqpacket_ops = {
1138 	.family		   = PF_INET,
1139 	.owner		   = THIS_MODULE,
1140 	.release	   = inet_release,	/* Needs to be wrapped... */
1141 	.bind		   = inet_bind,
1142 	.connect	   = sctp_inet_connect,
1143 	.socketpair	   = sock_no_socketpair,
1144 	.accept		   = inet_accept,
1145 	.getname	   = inet_getname,	/* Semantics are different.  */
1146 	.poll		   = sctp_poll,
1147 	.ioctl		   = inet_ioctl,
1148 	.gettstamp	   = sock_gettstamp,
1149 	.listen		   = sctp_inet_listen,
1150 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1151 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1152 	.getsockopt	   = sock_common_getsockopt,
1153 	.sendmsg	   = inet_sendmsg,
1154 	.recvmsg	   = inet_recvmsg,
1155 	.mmap		   = sock_no_mmap,
1156 };
1157 
1158 /* Registration with AF_INET family.  */
1159 static struct inet_protosw sctp_seqpacket_protosw = {
1160 	.type       = SOCK_SEQPACKET,
1161 	.protocol   = IPPROTO_SCTP,
1162 	.prot       = &sctp_prot,
1163 	.ops        = &inet_seqpacket_ops,
1164 	.flags      = SCTP_PROTOSW_FLAG
1165 };
1166 static struct inet_protosw sctp_stream_protosw = {
1167 	.type       = SOCK_STREAM,
1168 	.protocol   = IPPROTO_SCTP,
1169 	.prot       = &sctp_prot,
1170 	.ops        = &inet_seqpacket_ops,
1171 	.flags      = SCTP_PROTOSW_FLAG
1172 };
1173 
1174 static int sctp4_rcv(struct sk_buff *skb)
1175 {
1176 	SCTP_INPUT_CB(skb)->encap_port = 0;
1177 	return sctp_rcv(skb);
1178 }
1179 
1180 /* Register with IP layer.  */
1181 static const struct net_protocol sctp_protocol = {
1182 	.handler     = sctp4_rcv,
1183 	.err_handler = sctp_v4_err,
1184 	.no_policy   = 1,
1185 	.icmp_strict_tag_validation = 1,
1186 };
1187 
1188 /* IPv4 address related functions.  */
1189 static struct sctp_af sctp_af_inet = {
1190 	.sa_family	   = AF_INET,
1191 	.sctp_xmit	   = sctp_v4_xmit,
1192 	.setsockopt	   = ip_setsockopt,
1193 	.getsockopt	   = ip_getsockopt,
1194 	.get_dst	   = sctp_v4_get_dst,
1195 	.get_saddr	   = sctp_v4_get_saddr,
1196 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1197 	.from_skb	   = sctp_v4_from_skb,
1198 	.from_sk	   = sctp_v4_from_sk,
1199 	.from_addr_param   = sctp_v4_from_addr_param,
1200 	.to_addr_param	   = sctp_v4_to_addr_param,
1201 	.cmp_addr	   = sctp_v4_cmp_addr,
1202 	.addr_valid	   = sctp_v4_addr_valid,
1203 	.inaddr_any	   = sctp_v4_inaddr_any,
1204 	.is_any		   = sctp_v4_is_any,
1205 	.available	   = sctp_v4_available,
1206 	.scope		   = sctp_v4_scope,
1207 	.skb_iif	   = sctp_v4_skb_iif,
1208 	.skb_sdif	   = sctp_v4_skb_sdif,
1209 	.is_ce		   = sctp_v4_is_ce,
1210 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1211 	.ecn_capable	   = sctp_v4_ecn_capable,
1212 	.net_header_len	   = sizeof(struct iphdr),
1213 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1214 	.ip_options_len	   = sctp_v4_ip_options_len,
1215 };
1216 
1217 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1218 {
1219 	switch (family) {
1220 	case PF_INET:
1221 		return sctp_pf_inet_specific;
1222 	case PF_INET6:
1223 		return sctp_pf_inet6_specific;
1224 	default:
1225 		return NULL;
1226 	}
1227 }
1228 
1229 /* Register the PF specific function table.  */
1230 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1231 {
1232 	switch (family) {
1233 	case PF_INET:
1234 		if (sctp_pf_inet_specific)
1235 			return 0;
1236 		sctp_pf_inet_specific = pf;
1237 		break;
1238 	case PF_INET6:
1239 		if (sctp_pf_inet6_specific)
1240 			return 0;
1241 		sctp_pf_inet6_specific = pf;
1242 		break;
1243 	default:
1244 		return 0;
1245 	}
1246 	return 1;
1247 }
1248 
1249 static inline int init_sctp_mibs(struct net *net)
1250 {
1251 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1252 	if (!net->sctp.sctp_statistics)
1253 		return -ENOMEM;
1254 	return 0;
1255 }
1256 
1257 static inline void cleanup_sctp_mibs(struct net *net)
1258 {
1259 	free_percpu(net->sctp.sctp_statistics);
1260 }
1261 
1262 static void sctp_v4_pf_init(void)
1263 {
1264 	/* Initialize the SCTP specific PF functions. */
1265 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1266 	sctp_register_af(&sctp_af_inet);
1267 }
1268 
1269 static void sctp_v4_pf_exit(void)
1270 {
1271 	list_del(&sctp_af_inet.list);
1272 }
1273 
1274 static int sctp_v4_protosw_init(void)
1275 {
1276 	int rc;
1277 
1278 	rc = proto_register(&sctp_prot, 1);
1279 	if (rc)
1280 		return rc;
1281 
1282 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1283 	inet_register_protosw(&sctp_seqpacket_protosw);
1284 	inet_register_protosw(&sctp_stream_protosw);
1285 
1286 	return 0;
1287 }
1288 
1289 static void sctp_v4_protosw_exit(void)
1290 {
1291 	inet_unregister_protosw(&sctp_stream_protosw);
1292 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1293 	proto_unregister(&sctp_prot);
1294 }
1295 
1296 static int sctp_v4_add_protocol(void)
1297 {
1298 	/* Register notifier for inet address additions/deletions. */
1299 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1300 
1301 	/* Register SCTP with inet layer.  */
1302 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1303 		return -EAGAIN;
1304 
1305 	return 0;
1306 }
1307 
1308 static void sctp_v4_del_protocol(void)
1309 {
1310 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1311 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1312 }
1313 
1314 static int __net_init sctp_defaults_init(struct net *net)
1315 {
1316 	int status;
1317 
1318 	/*
1319 	 * 14. Suggested SCTP Protocol Parameter Values
1320 	 */
1321 	/* The following protocol parameters are RECOMMENDED:  */
1322 	/* RTO.Initial              - 3  seconds */
1323 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1324 	/* RTO.Min                  - 1  second */
1325 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1326 	/* RTO.Max                 -  60 seconds */
1327 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1328 	/* RTO.Alpha                - 1/8 */
1329 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1330 	/* RTO.Beta                 - 1/4 */
1331 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1332 
1333 	/* Valid.Cookie.Life        - 60  seconds */
1334 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1335 
1336 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1337 	net->sctp.cookie_preserve_enable 	= 1;
1338 
1339 	/* Default sctp sockets to use md5 as their hmac alg */
1340 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1341 	net->sctp.sctp_hmac_alg			= "md5";
1342 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1343 	net->sctp.sctp_hmac_alg			= "sha1";
1344 #else
1345 	net->sctp.sctp_hmac_alg			= NULL;
1346 #endif
1347 
1348 	/* Max.Burst		    - 4 */
1349 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1350 
1351 	/* Disable of Primary Path Switchover by default */
1352 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1353 
1354 	/* Enable pf state by default */
1355 	net->sctp.pf_enable = 1;
1356 
1357 	/* Ignore pf exposure feature by default */
1358 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1359 
1360 	/* Association.Max.Retrans  - 10 attempts
1361 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1362 	 * Max.Init.Retransmits     - 8  attempts
1363 	 */
1364 	net->sctp.max_retrans_association	= 10;
1365 	net->sctp.max_retrans_path		= 5;
1366 	net->sctp.max_retrans_init		= 8;
1367 
1368 	/* Sendbuffer growth	    - do per-socket accounting */
1369 	net->sctp.sndbuf_policy			= 0;
1370 
1371 	/* Rcvbuffer growth	    - do per-socket accounting */
1372 	net->sctp.rcvbuf_policy			= 0;
1373 
1374 	/* HB.interval              - 30 seconds */
1375 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1376 
1377 	/* delayed SACK timeout */
1378 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1379 
1380 	/* Disable ADDIP by default. */
1381 	net->sctp.addip_enable = 0;
1382 	net->sctp.addip_noauth = 0;
1383 	net->sctp.default_auto_asconf = 0;
1384 
1385 	/* Enable PR-SCTP by default. */
1386 	net->sctp.prsctp_enable = 1;
1387 
1388 	/* Disable RECONF by default. */
1389 	net->sctp.reconf_enable = 0;
1390 
1391 	/* Disable AUTH by default. */
1392 	net->sctp.auth_enable = 0;
1393 
1394 	/* Enable ECN by default. */
1395 	net->sctp.ecn_enable = 1;
1396 
1397 	/* Set UDP tunneling listening port to 0 by default */
1398 	net->sctp.udp_port = 0;
1399 
1400 	/* Set remote encap port to 0 by default */
1401 	net->sctp.encap_port = 0;
1402 
1403 	/* Set SCOPE policy to enabled */
1404 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1405 
1406 	/* Set the default rwnd update threshold */
1407 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1408 
1409 	/* Initialize maximum autoclose timeout. */
1410 	net->sctp.max_autoclose		= INT_MAX / HZ;
1411 
1412 #ifdef CONFIG_NET_L3_MASTER_DEV
1413 	net->sctp.l3mdev_accept = 1;
1414 #endif
1415 
1416 	status = sctp_sysctl_net_register(net);
1417 	if (status)
1418 		goto err_sysctl_register;
1419 
1420 	/* Allocate and initialise sctp mibs.  */
1421 	status = init_sctp_mibs(net);
1422 	if (status)
1423 		goto err_init_mibs;
1424 
1425 #ifdef CONFIG_PROC_FS
1426 	/* Initialize proc fs directory.  */
1427 	status = sctp_proc_init(net);
1428 	if (status)
1429 		goto err_init_proc;
1430 #endif
1431 
1432 	sctp_dbg_objcnt_init(net);
1433 
1434 	/* Initialize the local address list. */
1435 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1436 	spin_lock_init(&net->sctp.local_addr_lock);
1437 	sctp_get_local_addr_list(net);
1438 
1439 	/* Initialize the address event list */
1440 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1441 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1442 	spin_lock_init(&net->sctp.addr_wq_lock);
1443 	net->sctp.addr_wq_timer.expires = 0;
1444 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1445 
1446 	return 0;
1447 
1448 #ifdef CONFIG_PROC_FS
1449 err_init_proc:
1450 	cleanup_sctp_mibs(net);
1451 #endif
1452 err_init_mibs:
1453 	sctp_sysctl_net_unregister(net);
1454 err_sysctl_register:
1455 	return status;
1456 }
1457 
1458 static void __net_exit sctp_defaults_exit(struct net *net)
1459 {
1460 	/* Free the local address list */
1461 	sctp_free_addr_wq(net);
1462 	sctp_free_local_addr_list(net);
1463 
1464 #ifdef CONFIG_PROC_FS
1465 	remove_proc_subtree("sctp", net->proc_net);
1466 	net->sctp.proc_net_sctp = NULL;
1467 #endif
1468 	cleanup_sctp_mibs(net);
1469 	sctp_sysctl_net_unregister(net);
1470 }
1471 
1472 static struct pernet_operations sctp_defaults_ops = {
1473 	.init = sctp_defaults_init,
1474 	.exit = sctp_defaults_exit,
1475 };
1476 
1477 static int __net_init sctp_ctrlsock_init(struct net *net)
1478 {
1479 	int status;
1480 
1481 	/* Initialize the control inode/socket for handling OOTB packets.  */
1482 	status = sctp_ctl_sock_init(net);
1483 	if (status)
1484 		pr_err("Failed to initialize the SCTP control sock\n");
1485 
1486 	return status;
1487 }
1488 
1489 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1490 {
1491 	/* Free the control endpoint.  */
1492 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1493 }
1494 
1495 static struct pernet_operations sctp_ctrlsock_ops = {
1496 	.init = sctp_ctrlsock_init,
1497 	.exit = sctp_ctrlsock_exit,
1498 };
1499 
1500 /* Initialize the universe into something sensible.  */
1501 static __init int sctp_init(void)
1502 {
1503 	unsigned long nr_pages = totalram_pages();
1504 	unsigned long limit;
1505 	unsigned long goal;
1506 	int max_entry_order;
1507 	int num_entries;
1508 	int max_share;
1509 	int status;
1510 	int order;
1511 	int i;
1512 
1513 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1514 
1515 	/* Allocate bind_bucket and chunk caches. */
1516 	status = -ENOBUFS;
1517 	sctp_bucket_cachep = KMEM_CACHE(sctp_bind_bucket, SLAB_HWCACHE_ALIGN);
1518 	if (!sctp_bucket_cachep)
1519 		goto out;
1520 
1521 	sctp_chunk_cachep = KMEM_CACHE(sctp_chunk, SLAB_HWCACHE_ALIGN);
1522 	if (!sctp_chunk_cachep)
1523 		goto err_chunk_cachep;
1524 
1525 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1526 	if (status)
1527 		goto err_percpu_counter_init;
1528 
1529 	/* Implementation specific variables. */
1530 
1531 	/* Initialize default stream count setup information. */
1532 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1533 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1534 
1535 	/* Initialize handle used for association ids. */
1536 	idr_init(&sctp_assocs_id);
1537 
1538 	limit = nr_free_buffer_pages() / 8;
1539 	limit = max(limit, 128UL);
1540 	sysctl_sctp_mem[0] = limit / 4 * 3;
1541 	sysctl_sctp_mem[1] = limit;
1542 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1543 
1544 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1545 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1546 	max_share = min(4UL*1024*1024, limit);
1547 
1548 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1549 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1550 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1551 
1552 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1553 	sysctl_sctp_wmem[1] = 16*1024;
1554 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1555 
1556 	/* Size and allocate the association hash table.
1557 	 * The methodology is similar to that of the tcp hash tables.
1558 	 * Though not identical.  Start by getting a goal size
1559 	 */
1560 	if (nr_pages >= (128 * 1024))
1561 		goal = nr_pages >> (22 - PAGE_SHIFT);
1562 	else
1563 		goal = nr_pages >> (24 - PAGE_SHIFT);
1564 
1565 	/* Then compute the page order for said goal */
1566 	order = get_order(goal);
1567 
1568 	/* Now compute the required page order for the maximum sized table we
1569 	 * want to create
1570 	 */
1571 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1572 				    sizeof(struct sctp_bind_hashbucket));
1573 
1574 	/* Limit the page order by that maximum hash table size */
1575 	order = min(order, max_entry_order);
1576 
1577 	/* Allocate and initialize the endpoint hash table.  */
1578 	sctp_ep_hashsize = 64;
1579 	sctp_ep_hashtable =
1580 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1581 	if (!sctp_ep_hashtable) {
1582 		pr_err("Failed endpoint_hash alloc\n");
1583 		status = -ENOMEM;
1584 		goto err_ehash_alloc;
1585 	}
1586 	for (i = 0; i < sctp_ep_hashsize; i++) {
1587 		rwlock_init(&sctp_ep_hashtable[i].lock);
1588 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1589 	}
1590 
1591 	/* Allocate and initialize the SCTP port hash table.
1592 	 * Note that order is initalized to start at the max sized
1593 	 * table we want to support.  If we can't get that many pages
1594 	 * reduce the order and try again
1595 	 */
1596 	do {
1597 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1598 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1599 	} while (!sctp_port_hashtable && --order > 0);
1600 
1601 	if (!sctp_port_hashtable) {
1602 		pr_err("Failed bind hash alloc\n");
1603 		status = -ENOMEM;
1604 		goto err_bhash_alloc;
1605 	}
1606 
1607 	/* Now compute the number of entries that will fit in the
1608 	 * port hash space we allocated
1609 	 */
1610 	num_entries = (1UL << order) * PAGE_SIZE /
1611 		      sizeof(struct sctp_bind_hashbucket);
1612 
1613 	/* And finish by rounding it down to the nearest power of two.
1614 	 * This wastes some memory of course, but it's needed because
1615 	 * the hash function operates based on the assumption that
1616 	 * the number of entries is a power of two.
1617 	 */
1618 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1619 
1620 	for (i = 0; i < sctp_port_hashsize; i++) {
1621 		spin_lock_init(&sctp_port_hashtable[i].lock);
1622 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1623 	}
1624 
1625 	status = sctp_transport_hashtable_init();
1626 	if (status)
1627 		goto err_thash_alloc;
1628 
1629 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1630 		num_entries);
1631 
1632 	sctp_sysctl_register();
1633 
1634 	INIT_LIST_HEAD(&sctp_address_families);
1635 	sctp_v4_pf_init();
1636 	sctp_v6_pf_init();
1637 	sctp_sched_ops_init();
1638 
1639 	status = register_pernet_subsys(&sctp_defaults_ops);
1640 	if (status)
1641 		goto err_register_defaults;
1642 
1643 	status = sctp_v4_protosw_init();
1644 	if (status)
1645 		goto err_protosw_init;
1646 
1647 	status = sctp_v6_protosw_init();
1648 	if (status)
1649 		goto err_v6_protosw_init;
1650 
1651 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1652 	if (status)
1653 		goto err_register_ctrlsock;
1654 
1655 	status = sctp_v4_add_protocol();
1656 	if (status)
1657 		goto err_add_protocol;
1658 
1659 	/* Register SCTP with inet6 layer.  */
1660 	status = sctp_v6_add_protocol();
1661 	if (status)
1662 		goto err_v6_add_protocol;
1663 
1664 	if (sctp_offload_init() < 0)
1665 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1666 
1667 out:
1668 	return status;
1669 err_v6_add_protocol:
1670 	sctp_v4_del_protocol();
1671 err_add_protocol:
1672 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1673 err_register_ctrlsock:
1674 	sctp_v6_protosw_exit();
1675 err_v6_protosw_init:
1676 	sctp_v4_protosw_exit();
1677 err_protosw_init:
1678 	unregister_pernet_subsys(&sctp_defaults_ops);
1679 err_register_defaults:
1680 	sctp_v4_pf_exit();
1681 	sctp_v6_pf_exit();
1682 	sctp_sysctl_unregister();
1683 	free_pages((unsigned long)sctp_port_hashtable,
1684 		   get_order(sctp_port_hashsize *
1685 			     sizeof(struct sctp_bind_hashbucket)));
1686 err_bhash_alloc:
1687 	sctp_transport_hashtable_destroy();
1688 err_thash_alloc:
1689 	kfree(sctp_ep_hashtable);
1690 err_ehash_alloc:
1691 	percpu_counter_destroy(&sctp_sockets_allocated);
1692 err_percpu_counter_init:
1693 	kmem_cache_destroy(sctp_chunk_cachep);
1694 err_chunk_cachep:
1695 	kmem_cache_destroy(sctp_bucket_cachep);
1696 	goto out;
1697 }
1698 
1699 /* Exit handler for the SCTP protocol.  */
1700 static __exit void sctp_exit(void)
1701 {
1702 	/* BUG.  This should probably do something useful like clean
1703 	 * up all the remaining associations and all that memory.
1704 	 */
1705 
1706 	/* Unregister with inet6/inet layers. */
1707 	sctp_v6_del_protocol();
1708 	sctp_v4_del_protocol();
1709 
1710 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1711 
1712 	/* Free protosw registrations */
1713 	sctp_v6_protosw_exit();
1714 	sctp_v4_protosw_exit();
1715 
1716 	unregister_pernet_subsys(&sctp_defaults_ops);
1717 
1718 	/* Unregister with socket layer. */
1719 	sctp_v6_pf_exit();
1720 	sctp_v4_pf_exit();
1721 
1722 	sctp_sysctl_unregister();
1723 
1724 	free_pages((unsigned long)sctp_port_hashtable,
1725 		   get_order(sctp_port_hashsize *
1726 			     sizeof(struct sctp_bind_hashbucket)));
1727 	kfree(sctp_ep_hashtable);
1728 	sctp_transport_hashtable_destroy();
1729 
1730 	percpu_counter_destroy(&sctp_sockets_allocated);
1731 
1732 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1733 
1734 	kmem_cache_destroy(sctp_chunk_cachep);
1735 	kmem_cache_destroy(sctp_bucket_cachep);
1736 }
1737 
1738 module_init(sctp_init);
1739 module_exit(sctp_exit);
1740 
1741 /*
1742  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1743  */
1744 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1745 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1746 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1747 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1748 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1749 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1750 MODULE_LICENSE("GPL");
1751