xref: /linux/net/sctp/protocol.c (revision 8a4f6d023221c4b052ddfa1db48b27871bad6e96)
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/udp_tunnel.h>
47 
48 #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024)
49 
50 /* Global data structures. */
51 struct sctp_globals sctp_globals __read_mostly;
52 
53 struct idr sctp_assocs_id;
54 DEFINE_SPINLOCK(sctp_assocs_id_lock);
55 
56 static struct sctp_pf *sctp_pf_inet6_specific;
57 static struct sctp_pf *sctp_pf_inet_specific;
58 static struct sctp_af *sctp_af_v4_specific;
59 static struct sctp_af *sctp_af_v6_specific;
60 
61 struct kmem_cache *sctp_chunk_cachep __read_mostly;
62 struct kmem_cache *sctp_bucket_cachep __read_mostly;
63 
64 long sysctl_sctp_mem[3];
65 int sysctl_sctp_rmem[3];
66 int sysctl_sctp_wmem[3];
67 
68 /* Private helper to extract ipv4 address and stash them in
69  * the protocol structure.
70  */
71 static void sctp_v4_copy_addrlist(struct list_head *addrlist,
72 				  struct net_device *dev)
73 {
74 	struct in_device *in_dev;
75 	struct in_ifaddr *ifa;
76 	struct sctp_sockaddr_entry *addr;
77 
78 	rcu_read_lock();
79 	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
80 		rcu_read_unlock();
81 		return;
82 	}
83 
84 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
85 		/* Add the address to the local list.  */
86 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
87 		if (addr) {
88 			addr->a.v4.sin_family = AF_INET;
89 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
90 			addr->valid = 1;
91 			INIT_LIST_HEAD(&addr->list);
92 			list_add_tail(&addr->list, addrlist);
93 		}
94 	}
95 
96 	rcu_read_unlock();
97 }
98 
99 /* Extract our IP addresses from the system and stash them in the
100  * protocol structure.
101  */
102 static void sctp_get_local_addr_list(struct net *net)
103 {
104 	struct net_device *dev;
105 	struct list_head *pos;
106 	struct sctp_af *af;
107 
108 	rcu_read_lock();
109 	for_each_netdev_rcu(net, dev) {
110 		list_for_each(pos, &sctp_address_families) {
111 			af = list_entry(pos, struct sctp_af, list);
112 			af->copy_addrlist(&net->sctp.local_addr_list, dev);
113 		}
114 	}
115 	rcu_read_unlock();
116 }
117 
118 /* Free the existing local addresses.  */
119 static void sctp_free_local_addr_list(struct net *net)
120 {
121 	struct sctp_sockaddr_entry *addr;
122 	struct list_head *pos, *temp;
123 
124 	list_for_each_safe(pos, temp, &net->sctp.local_addr_list) {
125 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
126 		list_del(pos);
127 		kfree(addr);
128 	}
129 }
130 
131 /* Copy the local addresses which are valid for 'scope' into 'bp'.  */
132 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
133 			      enum sctp_scope scope, gfp_t gfp, int copy_flags)
134 {
135 	struct sctp_sockaddr_entry *addr;
136 	union sctp_addr laddr;
137 	int error = 0;
138 
139 	rcu_read_lock();
140 	list_for_each_entry_rcu(addr, &net->sctp.local_addr_list, list) {
141 		if (!addr->valid)
142 			continue;
143 		if (!sctp_in_scope(net, &addr->a, scope))
144 			continue;
145 
146 		/* Now that the address is in scope, check to see if
147 		 * the address type is really supported by the local
148 		 * sock as well as the remote peer.
149 		 */
150 		if (addr->a.sa.sa_family == AF_INET &&
151 		    (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
152 		     !(copy_flags & SCTP_ADDR4_PEERSUPP)))
153 			continue;
154 		if (addr->a.sa.sa_family == AF_INET6 &&
155 		    (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
156 		     !(copy_flags & SCTP_ADDR6_PEERSUPP)))
157 			continue;
158 
159 		laddr = addr->a;
160 		/* also works for setting ipv6 address port */
161 		laddr.v4.sin_port = htons(bp->port);
162 		if (sctp_bind_addr_state(bp, &laddr) != -1)
163 			continue;
164 
165 		error = sctp_add_bind_addr(bp, &addr->a, sizeof(addr->a),
166 					   SCTP_ADDR_SRC, GFP_ATOMIC);
167 		if (error)
168 			break;
169 	}
170 
171 	rcu_read_unlock();
172 	return error;
173 }
174 
175 /* Copy over any ip options */
176 static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
177 {
178 	struct inet_sock *newinet, *inet = inet_sk(sk);
179 	struct ip_options_rcu *inet_opt, *newopt = NULL;
180 
181 	newinet = inet_sk(newsk);
182 
183 	rcu_read_lock();
184 	inet_opt = rcu_dereference(inet->inet_opt);
185 	if (inet_opt) {
186 		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
187 				      inet_opt->opt.optlen, GFP_ATOMIC);
188 		if (newopt)
189 			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
190 			       inet_opt->opt.optlen);
191 		else
192 			pr_err("%s: Failed to copy ip options\n", __func__);
193 	}
194 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
195 	rcu_read_unlock();
196 }
197 
198 /* Account for the IP options */
199 static int sctp_v4_ip_options_len(struct sock *sk)
200 {
201 	struct inet_sock *inet = inet_sk(sk);
202 	struct ip_options_rcu *inet_opt;
203 	int len = 0;
204 
205 	rcu_read_lock();
206 	inet_opt = rcu_dereference(inet->inet_opt);
207 	if (inet_opt)
208 		len = inet_opt->opt.optlen;
209 
210 	rcu_read_unlock();
211 	return len;
212 }
213 
214 /* Initialize a sctp_addr from in incoming skb.  */
215 static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
216 			     int is_saddr)
217 {
218 	/* Always called on head skb, so this is safe */
219 	struct sctphdr *sh = sctp_hdr(skb);
220 	struct sockaddr_in *sa = &addr->v4;
221 
222 	addr->v4.sin_family = AF_INET;
223 
224 	if (is_saddr) {
225 		sa->sin_port = sh->source;
226 		sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
227 	} else {
228 		sa->sin_port = sh->dest;
229 		sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
230 	}
231 	memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
232 }
233 
234 /* Initialize an sctp_addr from a socket. */
235 static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
236 {
237 	addr->v4.sin_family = AF_INET;
238 	addr->v4.sin_port = 0;
239 	addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
240 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
241 }
242 
243 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
244 static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
245 {
246 	inet_sk(sk)->inet_rcv_saddr = addr->v4.sin_addr.s_addr;
247 }
248 
249 /* Initialize sk->sk_daddr from sctp_addr. */
250 static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
251 {
252 	inet_sk(sk)->inet_daddr = addr->v4.sin_addr.s_addr;
253 }
254 
255 /* Initialize a sctp_addr from an address parameter. */
256 static bool sctp_v4_from_addr_param(union sctp_addr *addr,
257 				    union sctp_addr_param *param,
258 				    __be16 port, int iif)
259 {
260 	if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
261 		return false;
262 
263 	addr->v4.sin_family = AF_INET;
264 	addr->v4.sin_port = port;
265 	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
266 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
267 
268 	return true;
269 }
270 
271 /* Initialize an address parameter from a sctp_addr and return the length
272  * of the address parameter.
273  */
274 static int sctp_v4_to_addr_param(const union sctp_addr *addr,
275 				 union sctp_addr_param *param)
276 {
277 	int length = sizeof(struct sctp_ipv4addr_param);
278 
279 	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
280 	param->v4.param_hdr.length = htons(length);
281 	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;
282 
283 	return length;
284 }
285 
286 /* Initialize a sctp_addr from a dst_entry. */
287 static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct flowi4 *fl4,
288 			      __be16 port)
289 {
290 	saddr->v4.sin_family = AF_INET;
291 	saddr->v4.sin_port = port;
292 	saddr->v4.sin_addr.s_addr = fl4->saddr;
293 	memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
294 }
295 
296 /* Compare two addresses exactly. */
297 static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
298 			    const union sctp_addr *addr2)
299 {
300 	if (addr1->sa.sa_family != addr2->sa.sa_family)
301 		return 0;
302 	if (addr1->v4.sin_port != addr2->v4.sin_port)
303 		return 0;
304 	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
305 		return 0;
306 
307 	return 1;
308 }
309 
310 /* Initialize addr struct to INADDR_ANY. */
311 static void sctp_v4_inaddr_any(union sctp_addr *addr, __be16 port)
312 {
313 	addr->v4.sin_family = AF_INET;
314 	addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
315 	addr->v4.sin_port = port;
316 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
317 }
318 
319 /* Is this a wildcard address? */
320 static int sctp_v4_is_any(const union sctp_addr *addr)
321 {
322 	return htonl(INADDR_ANY) == addr->v4.sin_addr.s_addr;
323 }
324 
325 /* This function checks if the address is a valid address to be used for
326  * SCTP binding.
327  *
328  * Output:
329  * Return 0 - If the address is a non-unicast or an illegal address.
330  * Return 1 - If the address is a unicast.
331  */
332 static int sctp_v4_addr_valid(union sctp_addr *addr,
333 			      struct sctp_sock *sp,
334 			      const struct sk_buff *skb)
335 {
336 	/* IPv4 addresses not allowed */
337 	if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
338 		return 0;
339 
340 	/* Is this a non-unicast address or a unusable SCTP address? */
341 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr))
342 		return 0;
343 
344 	/* Is this a broadcast address? */
345 	if (skb && skb_rtable(skb)->rt_flags & RTCF_BROADCAST)
346 		return 0;
347 
348 	return 1;
349 }
350 
351 /* Should this be available for binding?   */
352 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
353 {
354 	struct sock *sk = &sp->inet.sk;
355 	struct net *net = sock_net(sk);
356 	int tb_id = RT_TABLE_LOCAL;
357 	int ret;
358 
359 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
360 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
361 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
362 	   ret != RTN_LOCAL &&
363 	   !sp->inet.freebind &&
364 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
365 		return 0;
366 
367 	if (ipv6_only_sock(sctp_opt2sk(sp)))
368 		return 0;
369 
370 	return 1;
371 }
372 
373 /* Checking the loopback, private and other address scopes as defined in
374  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
375  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
376  *
377  * Level 0 - unusable SCTP addresses
378  * Level 1 - loopback address
379  * Level 2 - link-local addresses
380  * Level 3 - private addresses.
381  * Level 4 - global addresses
382  * For INIT and INIT-ACK address list, let L be the level of
383  * requested destination address, sender and receiver
384  * SHOULD include all of its addresses with level greater
385  * than or equal to L.
386  *
387  * IPv4 scoping can be controlled through sysctl option
388  * net.sctp.addr_scope_policy
389  */
390 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
391 {
392 	enum sctp_scope retval;
393 
394 	/* Check for unusable SCTP addresses. */
395 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
396 		retval =  SCTP_SCOPE_UNUSABLE;
397 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
398 		retval = SCTP_SCOPE_LOOPBACK;
399 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
400 		retval = SCTP_SCOPE_LINK;
401 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
402 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
403 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
404 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
405 		retval = SCTP_SCOPE_PRIVATE;
406 	} else {
407 		retval = SCTP_SCOPE_GLOBAL;
408 	}
409 
410 	return retval;
411 }
412 
413 /* Returns a valid dst cache entry for the given source and destination ip
414  * addresses. If an association is passed, trys to get a dst entry with a
415  * source address that matches an address in the bind address list.
416  */
417 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
418 				struct flowi *fl, struct sock *sk)
419 {
420 	struct sctp_association *asoc = t->asoc;
421 	struct rtable *rt;
422 	struct flowi _fl;
423 	struct flowi4 *fl4 = &_fl.u.ip4;
424 	struct sctp_bind_addr *bp;
425 	struct sctp_sockaddr_entry *laddr;
426 	struct dst_entry *dst = NULL;
427 	union sctp_addr *daddr = &t->ipaddr;
428 	union sctp_addr dst_saddr;
429 	__u8 tos = inet_sk(sk)->tos;
430 
431 	if (t->dscp & SCTP_DSCP_SET_MASK)
432 		tos = t->dscp & SCTP_DSCP_VAL_MASK;
433 	memset(&_fl, 0x0, sizeof(_fl));
434 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
435 	fl4->fl4_dport = daddr->v4.sin_port;
436 	fl4->flowi4_proto = IPPROTO_SCTP;
437 	if (asoc) {
438 		fl4->flowi4_tos = RT_CONN_FLAGS_TOS(asoc->base.sk, tos);
439 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
440 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
441 	}
442 	if (saddr) {
443 		fl4->saddr = saddr->v4.sin_addr.s_addr;
444 		if (!fl4->fl4_sport)
445 			fl4->fl4_sport = saddr->v4.sin_port;
446 	}
447 
448 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
449 		 &fl4->saddr);
450 
451 	rt = ip_route_output_key(sock_net(sk), fl4);
452 	if (!IS_ERR(rt)) {
453 		dst = &rt->dst;
454 		t->dst = dst;
455 		memcpy(fl, &_fl, sizeof(_fl));
456 	}
457 
458 	/* If there is no association or if a source address is passed, no
459 	 * more validation is required.
460 	 */
461 	if (!asoc || saddr)
462 		goto out;
463 
464 	bp = &asoc->base.bind_addr;
465 
466 	if (dst) {
467 		/* Walk through the bind address list and look for a bind
468 		 * address that matches the source address of the returned dst.
469 		 */
470 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
471 		rcu_read_lock();
472 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
473 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
474 			    (laddr->state != SCTP_ADDR_SRC &&
475 			    !asoc->src_out_of_asoc_ok))
476 				continue;
477 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
478 				goto out_unlock;
479 		}
480 		rcu_read_unlock();
481 
482 		/* None of the bound addresses match the source address of the
483 		 * dst. So release it.
484 		 */
485 		dst_release(dst);
486 		dst = NULL;
487 	}
488 
489 	/* Walk through the bind address list and try to get a dst that
490 	 * matches a bind address as the source address.
491 	 */
492 	rcu_read_lock();
493 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
494 		struct net_device *odev;
495 
496 		if (!laddr->valid)
497 			continue;
498 		if (laddr->state != SCTP_ADDR_SRC ||
499 		    AF_INET != laddr->a.sa.sa_family)
500 			continue;
501 
502 		fl4->fl4_sport = laddr->a.v4.sin_port;
503 		flowi4_update_output(fl4,
504 				     asoc->base.sk->sk_bound_dev_if,
505 				     RT_CONN_FLAGS_TOS(asoc->base.sk, tos),
506 				     daddr->v4.sin_addr.s_addr,
507 				     laddr->a.v4.sin_addr.s_addr);
508 
509 		rt = ip_route_output_key(sock_net(sk), fl4);
510 		if (IS_ERR(rt))
511 			continue;
512 
513 		/* Ensure the src address belongs to the output
514 		 * interface.
515 		 */
516 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
517 				     false);
518 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
519 			if (!dst) {
520 				dst = &rt->dst;
521 				t->dst = dst;
522 				memcpy(fl, &_fl, sizeof(_fl));
523 			} else {
524 				dst_release(&rt->dst);
525 			}
526 			continue;
527 		}
528 
529 		dst_release(dst);
530 		dst = &rt->dst;
531 		t->dst = dst;
532 		memcpy(fl, &_fl, sizeof(_fl));
533 		break;
534 	}
535 
536 out_unlock:
537 	rcu_read_unlock();
538 out:
539 	if (dst) {
540 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
541 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
542 	} else {
543 		t->dst = NULL;
544 		pr_debug("no route\n");
545 	}
546 }
547 
548 /* For v4, the source address is cached in the route entry(dst). So no need
549  * to cache it separately and hence this is an empty routine.
550  */
551 static void sctp_v4_get_saddr(struct sctp_sock *sk,
552 			      struct sctp_transport *t,
553 			      struct flowi *fl)
554 {
555 	union sctp_addr *saddr = &t->saddr;
556 	struct rtable *rt = (struct rtable *)t->dst;
557 
558 	if (rt) {
559 		saddr->v4.sin_family = AF_INET;
560 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
561 	}
562 }
563 
564 /* What interface did this skb arrive on? */
565 static int sctp_v4_skb_iif(const struct sk_buff *skb)
566 {
567 	return inet_iif(skb);
568 }
569 
570 static int sctp_v4_skb_sdif(const struct sk_buff *skb)
571 {
572 	return inet_sdif(skb);
573 }
574 
575 /* Was this packet marked by Explicit Congestion Notification? */
576 static int sctp_v4_is_ce(const struct sk_buff *skb)
577 {
578 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
579 }
580 
581 /* Create and initialize a new sk for the socket returned by accept(). */
582 static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
583 					     struct sctp_association *asoc,
584 					     bool kern)
585 {
586 	struct sock *newsk = sk_alloc(sock_net(sk), PF_INET, GFP_KERNEL,
587 			sk->sk_prot, kern);
588 	struct inet_sock *newinet;
589 
590 	if (!newsk)
591 		goto out;
592 
593 	sock_init_data(NULL, newsk);
594 
595 	sctp_copy_sock(newsk, sk, asoc);
596 	sock_reset_flag(newsk, SOCK_ZAPPED);
597 
598 	sctp_v4_copy_ip_options(sk, newsk);
599 
600 	newinet = inet_sk(newsk);
601 
602 	newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
603 
604 	sk_refcnt_debug_inc(newsk);
605 
606 	if (newsk->sk_prot->init(newsk)) {
607 		sk_common_release(newsk);
608 		newsk = NULL;
609 	}
610 
611 out:
612 	return newsk;
613 }
614 
615 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
616 {
617 	/* No address mapping for V4 sockets */
618 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
619 	return sizeof(struct sockaddr_in);
620 }
621 
622 /* Dump the v4 addr to the seq file. */
623 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
624 {
625 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
626 }
627 
628 static void sctp_v4_ecn_capable(struct sock *sk)
629 {
630 	INET_ECN_xmit(sk);
631 }
632 
633 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
634 {
635 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
636 	struct sctp_sockaddr_entry *addrw, *temp;
637 	struct sctp_sock *sp;
638 
639 	spin_lock_bh(&net->sctp.addr_wq_lock);
640 
641 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
642 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
643 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
644 			 addrw->state, addrw);
645 
646 #if IS_ENABLED(CONFIG_IPV6)
647 		/* Now we send an ASCONF for each association */
648 		/* Note. we currently don't handle link local IPv6 addressees */
649 		if (addrw->a.sa.sa_family == AF_INET6) {
650 			struct in6_addr *in6;
651 
652 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
653 			    IPV6_ADDR_LINKLOCAL)
654 				goto free_next;
655 
656 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
657 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
658 			    addrw->state == SCTP_ADDR_NEW) {
659 				unsigned long timeo_val;
660 
661 				pr_debug("%s: this is on DAD, trying %d sec "
662 					 "later\n", __func__,
663 					 SCTP_ADDRESS_TICK_DELAY);
664 
665 				timeo_val = jiffies;
666 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
667 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
668 				break;
669 			}
670 		}
671 #endif
672 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
673 			struct sock *sk;
674 
675 			sk = sctp_opt2sk(sp);
676 			/* ignore bound-specific endpoints */
677 			if (!sctp_is_ep_boundall(sk))
678 				continue;
679 			bh_lock_sock(sk);
680 			if (sctp_asconf_mgmt(sp, addrw) < 0)
681 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
682 			bh_unlock_sock(sk);
683 		}
684 #if IS_ENABLED(CONFIG_IPV6)
685 free_next:
686 #endif
687 		list_del(&addrw->list);
688 		kfree(addrw);
689 	}
690 	spin_unlock_bh(&net->sctp.addr_wq_lock);
691 }
692 
693 static void sctp_free_addr_wq(struct net *net)
694 {
695 	struct sctp_sockaddr_entry *addrw;
696 	struct sctp_sockaddr_entry *temp;
697 
698 	spin_lock_bh(&net->sctp.addr_wq_lock);
699 	del_timer(&net->sctp.addr_wq_timer);
700 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
701 		list_del(&addrw->list);
702 		kfree(addrw);
703 	}
704 	spin_unlock_bh(&net->sctp.addr_wq_lock);
705 }
706 
707 /* lookup the entry for the same address in the addr_waitq
708  * sctp_addr_wq MUST be locked
709  */
710 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
711 					struct sctp_sockaddr_entry *addr)
712 {
713 	struct sctp_sockaddr_entry *addrw;
714 
715 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
716 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
717 			continue;
718 		if (addrw->a.sa.sa_family == AF_INET) {
719 			if (addrw->a.v4.sin_addr.s_addr ==
720 			    addr->a.v4.sin_addr.s_addr)
721 				return addrw;
722 		} else if (addrw->a.sa.sa_family == AF_INET6) {
723 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
724 			    &addr->a.v6.sin6_addr))
725 				return addrw;
726 		}
727 	}
728 	return NULL;
729 }
730 
731 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
732 {
733 	struct sctp_sockaddr_entry *addrw;
734 	unsigned long timeo_val;
735 
736 	/* first, we check if an opposite message already exist in the queue.
737 	 * If we found such message, it is removed.
738 	 * This operation is a bit stupid, but the DHCP client attaches the
739 	 * new address after a couple of addition and deletion of that address
740 	 */
741 
742 	spin_lock_bh(&net->sctp.addr_wq_lock);
743 	/* Offsets existing events in addr_wq */
744 	addrw = sctp_addr_wq_lookup(net, addr);
745 	if (addrw) {
746 		if (addrw->state != cmd) {
747 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
748 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
749 				 &net->sctp.addr_waitq);
750 
751 			list_del(&addrw->list);
752 			kfree(addrw);
753 		}
754 		spin_unlock_bh(&net->sctp.addr_wq_lock);
755 		return;
756 	}
757 
758 	/* OK, we have to add the new address to the wait queue */
759 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
760 	if (addrw == NULL) {
761 		spin_unlock_bh(&net->sctp.addr_wq_lock);
762 		return;
763 	}
764 	addrw->state = cmd;
765 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
766 
767 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
768 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
769 
770 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
771 		timeo_val = jiffies;
772 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
773 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
774 	}
775 	spin_unlock_bh(&net->sctp.addr_wq_lock);
776 }
777 
778 /* Event handler for inet address addition/deletion events.
779  * The sctp_local_addr_list needs to be protocted by a spin lock since
780  * multiple notifiers (say IPv4 and IPv6) may be running at the same
781  * time and thus corrupt the list.
782  * The reader side is protected with RCU.
783  */
784 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
785 			       void *ptr)
786 {
787 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
788 	struct sctp_sockaddr_entry *addr = NULL;
789 	struct sctp_sockaddr_entry *temp;
790 	struct net *net = dev_net(ifa->ifa_dev->dev);
791 	int found = 0;
792 
793 	switch (ev) {
794 	case NETDEV_UP:
795 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
796 		if (addr) {
797 			addr->a.v4.sin_family = AF_INET;
798 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
799 			addr->valid = 1;
800 			spin_lock_bh(&net->sctp.local_addr_lock);
801 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
802 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
803 			spin_unlock_bh(&net->sctp.local_addr_lock);
804 		}
805 		break;
806 	case NETDEV_DOWN:
807 		spin_lock_bh(&net->sctp.local_addr_lock);
808 		list_for_each_entry_safe(addr, temp,
809 					&net->sctp.local_addr_list, list) {
810 			if (addr->a.sa.sa_family == AF_INET &&
811 					addr->a.v4.sin_addr.s_addr ==
812 					ifa->ifa_local) {
813 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
814 				found = 1;
815 				addr->valid = 0;
816 				list_del_rcu(&addr->list);
817 				break;
818 			}
819 		}
820 		spin_unlock_bh(&net->sctp.local_addr_lock);
821 		if (found)
822 			kfree_rcu(addr, rcu);
823 		break;
824 	}
825 
826 	return NOTIFY_DONE;
827 }
828 
829 /*
830  * Initialize the control inode/socket with a control endpoint data
831  * structure.  This endpoint is reserved exclusively for the OOTB processing.
832  */
833 static int sctp_ctl_sock_init(struct net *net)
834 {
835 	int err;
836 	sa_family_t family = PF_INET;
837 
838 	if (sctp_get_pf_specific(PF_INET6))
839 		family = PF_INET6;
840 
841 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
842 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
843 
844 	/* If IPv6 socket could not be created, try the IPv4 socket */
845 	if (err < 0 && family == PF_INET6)
846 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
847 					   SOCK_SEQPACKET, IPPROTO_SCTP,
848 					   net);
849 
850 	if (err < 0) {
851 		pr_err("Failed to create the SCTP control socket\n");
852 		return err;
853 	}
854 	return 0;
855 }
856 
857 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
858 {
859 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
860 
861 	skb_set_transport_header(skb, sizeof(struct udphdr));
862 	sctp_rcv(skb);
863 	return 0;
864 }
865 
866 int sctp_udp_sock_start(struct net *net)
867 {
868 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
869 	struct udp_port_cfg udp_conf = {0};
870 	struct socket *sock;
871 	int err;
872 
873 	udp_conf.family = AF_INET;
874 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
875 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
876 	err = udp_sock_create(net, &udp_conf, &sock);
877 	if (err) {
878 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
879 		return err;
880 	}
881 
882 	tuncfg.encap_type = 1;
883 	tuncfg.encap_rcv = sctp_udp_rcv;
884 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
885 	setup_udp_tunnel_sock(net, sock, &tuncfg);
886 	net->sctp.udp4_sock = sock->sk;
887 
888 #if IS_ENABLED(CONFIG_IPV6)
889 	memset(&udp_conf, 0, sizeof(udp_conf));
890 
891 	udp_conf.family = AF_INET6;
892 	udp_conf.local_ip6 = in6addr_any;
893 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
894 	udp_conf.use_udp6_rx_checksums = true;
895 	udp_conf.ipv6_v6only = true;
896 	err = udp_sock_create(net, &udp_conf, &sock);
897 	if (err) {
898 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
899 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
900 		net->sctp.udp4_sock = NULL;
901 		return err;
902 	}
903 
904 	tuncfg.encap_type = 1;
905 	tuncfg.encap_rcv = sctp_udp_rcv;
906 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
907 	setup_udp_tunnel_sock(net, sock, &tuncfg);
908 	net->sctp.udp6_sock = sock->sk;
909 #endif
910 
911 	return 0;
912 }
913 
914 void sctp_udp_sock_stop(struct net *net)
915 {
916 	if (net->sctp.udp4_sock) {
917 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
918 		net->sctp.udp4_sock = NULL;
919 	}
920 	if (net->sctp.udp6_sock) {
921 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
922 		net->sctp.udp6_sock = NULL;
923 	}
924 }
925 
926 /* Register address family specific functions. */
927 int sctp_register_af(struct sctp_af *af)
928 {
929 	switch (af->sa_family) {
930 	case AF_INET:
931 		if (sctp_af_v4_specific)
932 			return 0;
933 		sctp_af_v4_specific = af;
934 		break;
935 	case AF_INET6:
936 		if (sctp_af_v6_specific)
937 			return 0;
938 		sctp_af_v6_specific = af;
939 		break;
940 	default:
941 		return 0;
942 	}
943 
944 	INIT_LIST_HEAD(&af->list);
945 	list_add_tail(&af->list, &sctp_address_families);
946 	return 1;
947 }
948 
949 /* Get the table of functions for manipulating a particular address
950  * family.
951  */
952 struct sctp_af *sctp_get_af_specific(sa_family_t family)
953 {
954 	switch (family) {
955 	case AF_INET:
956 		return sctp_af_v4_specific;
957 	case AF_INET6:
958 		return sctp_af_v6_specific;
959 	default:
960 		return NULL;
961 	}
962 }
963 
964 /* Common code to initialize a AF_INET msg_name. */
965 static void sctp_inet_msgname(char *msgname, int *addr_len)
966 {
967 	struct sockaddr_in *sin;
968 
969 	sin = (struct sockaddr_in *)msgname;
970 	*addr_len = sizeof(struct sockaddr_in);
971 	sin->sin_family = AF_INET;
972 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
973 }
974 
975 /* Copy the primary address of the peer primary address as the msg_name. */
976 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
977 				    int *addr_len)
978 {
979 	struct sockaddr_in *sin, *sinfrom;
980 
981 	if (msgname) {
982 		struct sctp_association *asoc;
983 
984 		asoc = event->asoc;
985 		sctp_inet_msgname(msgname, addr_len);
986 		sin = (struct sockaddr_in *)msgname;
987 		sinfrom = &asoc->peer.primary_addr.v4;
988 		sin->sin_port = htons(asoc->peer.port);
989 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
990 	}
991 }
992 
993 /* Initialize and copy out a msgname from an inbound skb. */
994 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
995 {
996 	if (msgname) {
997 		struct sctphdr *sh = sctp_hdr(skb);
998 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
999 
1000 		sctp_inet_msgname(msgname, len);
1001 		sin->sin_port = sh->source;
1002 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1003 	}
1004 }
1005 
1006 /* Do we support this AF? */
1007 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1008 {
1009 	/* PF_INET only supports AF_INET addresses. */
1010 	return AF_INET == family;
1011 }
1012 
1013 /* Address matching with wildcards allowed. */
1014 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1015 			      const union sctp_addr *addr2,
1016 			      struct sctp_sock *opt)
1017 {
1018 	/* PF_INET only supports AF_INET addresses. */
1019 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1020 		return 0;
1021 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1022 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1023 		return 1;
1024 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1025 		return 1;
1026 
1027 	return 0;
1028 }
1029 
1030 /* Verify that provided sockaddr looks bindable.  Common verification has
1031  * already been taken care of.
1032  */
1033 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1034 {
1035 	return sctp_v4_available(addr, opt);
1036 }
1037 
1038 /* Verify that sockaddr looks sendable.  Common verification has already
1039  * been taken care of.
1040  */
1041 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1042 {
1043 	return 1;
1044 }
1045 
1046 /* Fill in Supported Address Type information for INIT and INIT-ACK
1047  * chunks.  Returns number of addresses supported.
1048  */
1049 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1050 				     __be16 *types)
1051 {
1052 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1053 	return 1;
1054 }
1055 
1056 /* Wrapper routine that calls the ip transmit routine. */
1057 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1058 {
1059 	struct dst_entry *dst = dst_clone(t->dst);
1060 	struct flowi4 *fl4 = &t->fl.u.ip4;
1061 	struct sock *sk = skb->sk;
1062 	struct inet_sock *inet = inet_sk(sk);
1063 	__u8 dscp = inet->tos;
1064 	__be16 df = 0;
1065 
1066 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1067 		 skb->len, &fl4->saddr, &fl4->daddr);
1068 
1069 	if (t->dscp & SCTP_DSCP_SET_MASK)
1070 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1071 
1072 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1073 							   : IP_PMTUDISC_DONT;
1074 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1075 
1076 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1077 		skb_dst_set(skb, dst);
1078 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1079 	}
1080 
1081 	if (skb_is_gso(skb))
1082 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1083 
1084 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1085 		df = htons(IP_DF);
1086 
1087 	skb->encapsulation = 1;
1088 	skb_reset_inner_mac_header(skb);
1089 	skb_reset_inner_transport_header(skb);
1090 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1091 	udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr,
1092 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1093 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1094 	return 0;
1095 }
1096 
1097 static struct sctp_af sctp_af_inet;
1098 
1099 static struct sctp_pf sctp_pf_inet = {
1100 	.event_msgname = sctp_inet_event_msgname,
1101 	.skb_msgname   = sctp_inet_skb_msgname,
1102 	.af_supported  = sctp_inet_af_supported,
1103 	.cmp_addr      = sctp_inet_cmp_addr,
1104 	.bind_verify   = sctp_inet_bind_verify,
1105 	.send_verify   = sctp_inet_send_verify,
1106 	.supported_addrs = sctp_inet_supported_addrs,
1107 	.create_accept_sk = sctp_v4_create_accept_sk,
1108 	.addr_to_user  = sctp_v4_addr_to_user,
1109 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1110 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1111 	.copy_ip_options = sctp_v4_copy_ip_options,
1112 	.af            = &sctp_af_inet
1113 };
1114 
1115 /* Notifier for inetaddr addition/deletion events.  */
1116 static struct notifier_block sctp_inetaddr_notifier = {
1117 	.notifier_call = sctp_inetaddr_event,
1118 };
1119 
1120 /* Socket operations.  */
1121 static const struct proto_ops inet_seqpacket_ops = {
1122 	.family		   = PF_INET,
1123 	.owner		   = THIS_MODULE,
1124 	.release	   = inet_release,	/* Needs to be wrapped... */
1125 	.bind		   = inet_bind,
1126 	.connect	   = sctp_inet_connect,
1127 	.socketpair	   = sock_no_socketpair,
1128 	.accept		   = inet_accept,
1129 	.getname	   = inet_getname,	/* Semantics are different.  */
1130 	.poll		   = sctp_poll,
1131 	.ioctl		   = inet_ioctl,
1132 	.gettstamp	   = sock_gettstamp,
1133 	.listen		   = sctp_inet_listen,
1134 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1135 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1136 	.getsockopt	   = sock_common_getsockopt,
1137 	.sendmsg	   = inet_sendmsg,
1138 	.recvmsg	   = inet_recvmsg,
1139 	.mmap		   = sock_no_mmap,
1140 	.sendpage	   = sock_no_sendpage,
1141 };
1142 
1143 /* Registration with AF_INET family.  */
1144 static struct inet_protosw sctp_seqpacket_protosw = {
1145 	.type       = SOCK_SEQPACKET,
1146 	.protocol   = IPPROTO_SCTP,
1147 	.prot       = &sctp_prot,
1148 	.ops        = &inet_seqpacket_ops,
1149 	.flags      = SCTP_PROTOSW_FLAG
1150 };
1151 static struct inet_protosw sctp_stream_protosw = {
1152 	.type       = SOCK_STREAM,
1153 	.protocol   = IPPROTO_SCTP,
1154 	.prot       = &sctp_prot,
1155 	.ops        = &inet_seqpacket_ops,
1156 	.flags      = SCTP_PROTOSW_FLAG
1157 };
1158 
1159 static int sctp4_rcv(struct sk_buff *skb)
1160 {
1161 	SCTP_INPUT_CB(skb)->encap_port = 0;
1162 	return sctp_rcv(skb);
1163 }
1164 
1165 /* Register with IP layer.  */
1166 static const struct net_protocol sctp_protocol = {
1167 	.handler     = sctp4_rcv,
1168 	.err_handler = sctp_v4_err,
1169 	.no_policy   = 1,
1170 	.icmp_strict_tag_validation = 1,
1171 };
1172 
1173 /* IPv4 address related functions.  */
1174 static struct sctp_af sctp_af_inet = {
1175 	.sa_family	   = AF_INET,
1176 	.sctp_xmit	   = sctp_v4_xmit,
1177 	.setsockopt	   = ip_setsockopt,
1178 	.getsockopt	   = ip_getsockopt,
1179 	.get_dst	   = sctp_v4_get_dst,
1180 	.get_saddr	   = sctp_v4_get_saddr,
1181 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1182 	.from_skb	   = sctp_v4_from_skb,
1183 	.from_sk	   = sctp_v4_from_sk,
1184 	.from_addr_param   = sctp_v4_from_addr_param,
1185 	.to_addr_param	   = sctp_v4_to_addr_param,
1186 	.cmp_addr	   = sctp_v4_cmp_addr,
1187 	.addr_valid	   = sctp_v4_addr_valid,
1188 	.inaddr_any	   = sctp_v4_inaddr_any,
1189 	.is_any		   = sctp_v4_is_any,
1190 	.available	   = sctp_v4_available,
1191 	.scope		   = sctp_v4_scope,
1192 	.skb_iif	   = sctp_v4_skb_iif,
1193 	.skb_sdif	   = sctp_v4_skb_sdif,
1194 	.is_ce		   = sctp_v4_is_ce,
1195 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1196 	.ecn_capable	   = sctp_v4_ecn_capable,
1197 	.net_header_len	   = sizeof(struct iphdr),
1198 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1199 	.ip_options_len	   = sctp_v4_ip_options_len,
1200 };
1201 
1202 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1203 {
1204 	switch (family) {
1205 	case PF_INET:
1206 		return sctp_pf_inet_specific;
1207 	case PF_INET6:
1208 		return sctp_pf_inet6_specific;
1209 	default:
1210 		return NULL;
1211 	}
1212 }
1213 
1214 /* Register the PF specific function table.  */
1215 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1216 {
1217 	switch (family) {
1218 	case PF_INET:
1219 		if (sctp_pf_inet_specific)
1220 			return 0;
1221 		sctp_pf_inet_specific = pf;
1222 		break;
1223 	case PF_INET6:
1224 		if (sctp_pf_inet6_specific)
1225 			return 0;
1226 		sctp_pf_inet6_specific = pf;
1227 		break;
1228 	default:
1229 		return 0;
1230 	}
1231 	return 1;
1232 }
1233 
1234 static inline int init_sctp_mibs(struct net *net)
1235 {
1236 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1237 	if (!net->sctp.sctp_statistics)
1238 		return -ENOMEM;
1239 	return 0;
1240 }
1241 
1242 static inline void cleanup_sctp_mibs(struct net *net)
1243 {
1244 	free_percpu(net->sctp.sctp_statistics);
1245 }
1246 
1247 static void sctp_v4_pf_init(void)
1248 {
1249 	/* Initialize the SCTP specific PF functions. */
1250 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1251 	sctp_register_af(&sctp_af_inet);
1252 }
1253 
1254 static void sctp_v4_pf_exit(void)
1255 {
1256 	list_del(&sctp_af_inet.list);
1257 }
1258 
1259 static int sctp_v4_protosw_init(void)
1260 {
1261 	int rc;
1262 
1263 	rc = proto_register(&sctp_prot, 1);
1264 	if (rc)
1265 		return rc;
1266 
1267 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1268 	inet_register_protosw(&sctp_seqpacket_protosw);
1269 	inet_register_protosw(&sctp_stream_protosw);
1270 
1271 	return 0;
1272 }
1273 
1274 static void sctp_v4_protosw_exit(void)
1275 {
1276 	inet_unregister_protosw(&sctp_stream_protosw);
1277 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1278 	proto_unregister(&sctp_prot);
1279 }
1280 
1281 static int sctp_v4_add_protocol(void)
1282 {
1283 	/* Register notifier for inet address additions/deletions. */
1284 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1285 
1286 	/* Register SCTP with inet layer.  */
1287 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1288 		return -EAGAIN;
1289 
1290 	return 0;
1291 }
1292 
1293 static void sctp_v4_del_protocol(void)
1294 {
1295 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1296 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1297 }
1298 
1299 static int __net_init sctp_defaults_init(struct net *net)
1300 {
1301 	int status;
1302 
1303 	/*
1304 	 * 14. Suggested SCTP Protocol Parameter Values
1305 	 */
1306 	/* The following protocol parameters are RECOMMENDED:  */
1307 	/* RTO.Initial              - 3  seconds */
1308 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1309 	/* RTO.Min                  - 1  second */
1310 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1311 	/* RTO.Max                 -  60 seconds */
1312 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1313 	/* RTO.Alpha                - 1/8 */
1314 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1315 	/* RTO.Beta                 - 1/4 */
1316 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1317 
1318 	/* Valid.Cookie.Life        - 60  seconds */
1319 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1320 
1321 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1322 	net->sctp.cookie_preserve_enable 	= 1;
1323 
1324 	/* Default sctp sockets to use md5 as their hmac alg */
1325 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1326 	net->sctp.sctp_hmac_alg			= "md5";
1327 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1328 	net->sctp.sctp_hmac_alg			= "sha1";
1329 #else
1330 	net->sctp.sctp_hmac_alg			= NULL;
1331 #endif
1332 
1333 	/* Max.Burst		    - 4 */
1334 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1335 
1336 	/* Disable of Primary Path Switchover by default */
1337 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1338 
1339 	/* Enable pf state by default */
1340 	net->sctp.pf_enable = 1;
1341 
1342 	/* Ignore pf exposure feature by default */
1343 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1344 
1345 	/* Association.Max.Retrans  - 10 attempts
1346 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1347 	 * Max.Init.Retransmits     - 8  attempts
1348 	 */
1349 	net->sctp.max_retrans_association	= 10;
1350 	net->sctp.max_retrans_path		= 5;
1351 	net->sctp.max_retrans_init		= 8;
1352 
1353 	/* Sendbuffer growth	    - do per-socket accounting */
1354 	net->sctp.sndbuf_policy			= 0;
1355 
1356 	/* Rcvbuffer growth	    - do per-socket accounting */
1357 	net->sctp.rcvbuf_policy			= 0;
1358 
1359 	/* HB.interval              - 30 seconds */
1360 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1361 
1362 	/* delayed SACK timeout */
1363 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1364 
1365 	/* Disable ADDIP by default. */
1366 	net->sctp.addip_enable = 0;
1367 	net->sctp.addip_noauth = 0;
1368 	net->sctp.default_auto_asconf = 0;
1369 
1370 	/* Enable PR-SCTP by default. */
1371 	net->sctp.prsctp_enable = 1;
1372 
1373 	/* Disable RECONF by default. */
1374 	net->sctp.reconf_enable = 0;
1375 
1376 	/* Disable AUTH by default. */
1377 	net->sctp.auth_enable = 0;
1378 
1379 	/* Enable ECN by default. */
1380 	net->sctp.ecn_enable = 1;
1381 
1382 	/* Set UDP tunneling listening port to 0 by default */
1383 	net->sctp.udp_port = 0;
1384 
1385 	/* Set remote encap port to 0 by default */
1386 	net->sctp.encap_port = 0;
1387 
1388 	/* Set SCOPE policy to enabled */
1389 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1390 
1391 	/* Set the default rwnd update threshold */
1392 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1393 
1394 	/* Initialize maximum autoclose timeout. */
1395 	net->sctp.max_autoclose		= INT_MAX / HZ;
1396 
1397 #ifdef CONFIG_NET_L3_MASTER_DEV
1398 	net->sctp.l3mdev_accept = 1;
1399 #endif
1400 
1401 	status = sctp_sysctl_net_register(net);
1402 	if (status)
1403 		goto err_sysctl_register;
1404 
1405 	/* Allocate and initialise sctp mibs.  */
1406 	status = init_sctp_mibs(net);
1407 	if (status)
1408 		goto err_init_mibs;
1409 
1410 #ifdef CONFIG_PROC_FS
1411 	/* Initialize proc fs directory.  */
1412 	status = sctp_proc_init(net);
1413 	if (status)
1414 		goto err_init_proc;
1415 #endif
1416 
1417 	sctp_dbg_objcnt_init(net);
1418 
1419 	/* Initialize the local address list. */
1420 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1421 	spin_lock_init(&net->sctp.local_addr_lock);
1422 	sctp_get_local_addr_list(net);
1423 
1424 	/* Initialize the address event list */
1425 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1426 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1427 	spin_lock_init(&net->sctp.addr_wq_lock);
1428 	net->sctp.addr_wq_timer.expires = 0;
1429 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1430 
1431 	return 0;
1432 
1433 #ifdef CONFIG_PROC_FS
1434 err_init_proc:
1435 	cleanup_sctp_mibs(net);
1436 #endif
1437 err_init_mibs:
1438 	sctp_sysctl_net_unregister(net);
1439 err_sysctl_register:
1440 	return status;
1441 }
1442 
1443 static void __net_exit sctp_defaults_exit(struct net *net)
1444 {
1445 	/* Free the local address list */
1446 	sctp_free_addr_wq(net);
1447 	sctp_free_local_addr_list(net);
1448 
1449 #ifdef CONFIG_PROC_FS
1450 	remove_proc_subtree("sctp", net->proc_net);
1451 	net->sctp.proc_net_sctp = NULL;
1452 #endif
1453 	cleanup_sctp_mibs(net);
1454 	sctp_sysctl_net_unregister(net);
1455 }
1456 
1457 static struct pernet_operations sctp_defaults_ops = {
1458 	.init = sctp_defaults_init,
1459 	.exit = sctp_defaults_exit,
1460 };
1461 
1462 static int __net_init sctp_ctrlsock_init(struct net *net)
1463 {
1464 	int status;
1465 
1466 	/* Initialize the control inode/socket for handling OOTB packets.  */
1467 	status = sctp_ctl_sock_init(net);
1468 	if (status)
1469 		pr_err("Failed to initialize the SCTP control sock\n");
1470 
1471 	return status;
1472 }
1473 
1474 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1475 {
1476 	/* Free the control endpoint.  */
1477 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1478 }
1479 
1480 static struct pernet_operations sctp_ctrlsock_ops = {
1481 	.init = sctp_ctrlsock_init,
1482 	.exit = sctp_ctrlsock_exit,
1483 };
1484 
1485 /* Initialize the universe into something sensible.  */
1486 static __init int sctp_init(void)
1487 {
1488 	unsigned long nr_pages = totalram_pages();
1489 	unsigned long limit;
1490 	unsigned long goal;
1491 	int max_entry_order;
1492 	int num_entries;
1493 	int max_share;
1494 	int status;
1495 	int order;
1496 	int i;
1497 
1498 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1499 
1500 	/* Allocate bind_bucket and chunk caches. */
1501 	status = -ENOBUFS;
1502 	sctp_bucket_cachep = kmem_cache_create("sctp_bind_bucket",
1503 					       sizeof(struct sctp_bind_bucket),
1504 					       0, SLAB_HWCACHE_ALIGN,
1505 					       NULL);
1506 	if (!sctp_bucket_cachep)
1507 		goto out;
1508 
1509 	sctp_chunk_cachep = kmem_cache_create("sctp_chunk",
1510 					       sizeof(struct sctp_chunk),
1511 					       0, SLAB_HWCACHE_ALIGN,
1512 					       NULL);
1513 	if (!sctp_chunk_cachep)
1514 		goto err_chunk_cachep;
1515 
1516 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1517 	if (status)
1518 		goto err_percpu_counter_init;
1519 
1520 	/* Implementation specific variables. */
1521 
1522 	/* Initialize default stream count setup information. */
1523 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1524 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1525 
1526 	/* Initialize handle used for association ids. */
1527 	idr_init(&sctp_assocs_id);
1528 
1529 	limit = nr_free_buffer_pages() / 8;
1530 	limit = max(limit, 128UL);
1531 	sysctl_sctp_mem[0] = limit / 4 * 3;
1532 	sysctl_sctp_mem[1] = limit;
1533 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1534 
1535 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1536 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1537 	max_share = min(4UL*1024*1024, limit);
1538 
1539 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1540 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1541 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1542 
1543 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1544 	sysctl_sctp_wmem[1] = 16*1024;
1545 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1546 
1547 	/* Size and allocate the association hash table.
1548 	 * The methodology is similar to that of the tcp hash tables.
1549 	 * Though not identical.  Start by getting a goal size
1550 	 */
1551 	if (nr_pages >= (128 * 1024))
1552 		goal = nr_pages >> (22 - PAGE_SHIFT);
1553 	else
1554 		goal = nr_pages >> (24 - PAGE_SHIFT);
1555 
1556 	/* Then compute the page order for said goal */
1557 	order = get_order(goal);
1558 
1559 	/* Now compute the required page order for the maximum sized table we
1560 	 * want to create
1561 	 */
1562 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1563 				    sizeof(struct sctp_bind_hashbucket));
1564 
1565 	/* Limit the page order by that maximum hash table size */
1566 	order = min(order, max_entry_order);
1567 
1568 	/* Allocate and initialize the endpoint hash table.  */
1569 	sctp_ep_hashsize = 64;
1570 	sctp_ep_hashtable =
1571 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1572 	if (!sctp_ep_hashtable) {
1573 		pr_err("Failed endpoint_hash alloc\n");
1574 		status = -ENOMEM;
1575 		goto err_ehash_alloc;
1576 	}
1577 	for (i = 0; i < sctp_ep_hashsize; i++) {
1578 		rwlock_init(&sctp_ep_hashtable[i].lock);
1579 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1580 	}
1581 
1582 	/* Allocate and initialize the SCTP port hash table.
1583 	 * Note that order is initalized to start at the max sized
1584 	 * table we want to support.  If we can't get that many pages
1585 	 * reduce the order and try again
1586 	 */
1587 	do {
1588 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1589 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1590 	} while (!sctp_port_hashtable && --order > 0);
1591 
1592 	if (!sctp_port_hashtable) {
1593 		pr_err("Failed bind hash alloc\n");
1594 		status = -ENOMEM;
1595 		goto err_bhash_alloc;
1596 	}
1597 
1598 	/* Now compute the number of entries that will fit in the
1599 	 * port hash space we allocated
1600 	 */
1601 	num_entries = (1UL << order) * PAGE_SIZE /
1602 		      sizeof(struct sctp_bind_hashbucket);
1603 
1604 	/* And finish by rounding it down to the nearest power of two.
1605 	 * This wastes some memory of course, but it's needed because
1606 	 * the hash function operates based on the assumption that
1607 	 * the number of entries is a power of two.
1608 	 */
1609 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1610 
1611 	for (i = 0; i < sctp_port_hashsize; i++) {
1612 		spin_lock_init(&sctp_port_hashtable[i].lock);
1613 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1614 	}
1615 
1616 	status = sctp_transport_hashtable_init();
1617 	if (status)
1618 		goto err_thash_alloc;
1619 
1620 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1621 		num_entries);
1622 
1623 	sctp_sysctl_register();
1624 
1625 	INIT_LIST_HEAD(&sctp_address_families);
1626 	sctp_v4_pf_init();
1627 	sctp_v6_pf_init();
1628 	sctp_sched_ops_init();
1629 
1630 	status = register_pernet_subsys(&sctp_defaults_ops);
1631 	if (status)
1632 		goto err_register_defaults;
1633 
1634 	status = sctp_v4_protosw_init();
1635 	if (status)
1636 		goto err_protosw_init;
1637 
1638 	status = sctp_v6_protosw_init();
1639 	if (status)
1640 		goto err_v6_protosw_init;
1641 
1642 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1643 	if (status)
1644 		goto err_register_ctrlsock;
1645 
1646 	status = sctp_v4_add_protocol();
1647 	if (status)
1648 		goto err_add_protocol;
1649 
1650 	/* Register SCTP with inet6 layer.  */
1651 	status = sctp_v6_add_protocol();
1652 	if (status)
1653 		goto err_v6_add_protocol;
1654 
1655 	if (sctp_offload_init() < 0)
1656 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1657 
1658 out:
1659 	return status;
1660 err_v6_add_protocol:
1661 	sctp_v4_del_protocol();
1662 err_add_protocol:
1663 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1664 err_register_ctrlsock:
1665 	sctp_v6_protosw_exit();
1666 err_v6_protosw_init:
1667 	sctp_v4_protosw_exit();
1668 err_protosw_init:
1669 	unregister_pernet_subsys(&sctp_defaults_ops);
1670 err_register_defaults:
1671 	sctp_v4_pf_exit();
1672 	sctp_v6_pf_exit();
1673 	sctp_sysctl_unregister();
1674 	free_pages((unsigned long)sctp_port_hashtable,
1675 		   get_order(sctp_port_hashsize *
1676 			     sizeof(struct sctp_bind_hashbucket)));
1677 err_bhash_alloc:
1678 	sctp_transport_hashtable_destroy();
1679 err_thash_alloc:
1680 	kfree(sctp_ep_hashtable);
1681 err_ehash_alloc:
1682 	percpu_counter_destroy(&sctp_sockets_allocated);
1683 err_percpu_counter_init:
1684 	kmem_cache_destroy(sctp_chunk_cachep);
1685 err_chunk_cachep:
1686 	kmem_cache_destroy(sctp_bucket_cachep);
1687 	goto out;
1688 }
1689 
1690 /* Exit handler for the SCTP protocol.  */
1691 static __exit void sctp_exit(void)
1692 {
1693 	/* BUG.  This should probably do something useful like clean
1694 	 * up all the remaining associations and all that memory.
1695 	 */
1696 
1697 	/* Unregister with inet6/inet layers. */
1698 	sctp_v6_del_protocol();
1699 	sctp_v4_del_protocol();
1700 
1701 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1702 
1703 	/* Free protosw registrations */
1704 	sctp_v6_protosw_exit();
1705 	sctp_v4_protosw_exit();
1706 
1707 	unregister_pernet_subsys(&sctp_defaults_ops);
1708 
1709 	/* Unregister with socket layer. */
1710 	sctp_v6_pf_exit();
1711 	sctp_v4_pf_exit();
1712 
1713 	sctp_sysctl_unregister();
1714 
1715 	free_pages((unsigned long)sctp_port_hashtable,
1716 		   get_order(sctp_port_hashsize *
1717 			     sizeof(struct sctp_bind_hashbucket)));
1718 	kfree(sctp_ep_hashtable);
1719 	sctp_transport_hashtable_destroy();
1720 
1721 	percpu_counter_destroy(&sctp_sockets_allocated);
1722 
1723 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1724 
1725 	kmem_cache_destroy(sctp_chunk_cachep);
1726 	kmem_cache_destroy(sctp_bucket_cachep);
1727 }
1728 
1729 module_init(sctp_init);
1730 module_exit(sctp_exit);
1731 
1732 /*
1733  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1734  */
1735 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1736 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1737 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1738 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1739 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1740 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1741 MODULE_LICENSE("GPL");
1742