xref: /linux/net/sctp/protocol.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
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 #include <net/inet_dscp.h>
48 
49 #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024)
50 
51 /* Global data structures. */
52 struct sctp_globals sctp_globals __read_mostly;
53 
54 struct idr sctp_assocs_id;
55 DEFINE_SPINLOCK(sctp_assocs_id_lock);
56 
57 static struct sctp_pf *sctp_pf_inet6_specific;
58 static struct sctp_pf *sctp_pf_inet_specific;
59 static struct sctp_af *sctp_af_v4_specific;
60 static struct sctp_af *sctp_af_v6_specific;
61 
62 struct kmem_cache *sctp_chunk_cachep __read_mostly;
63 struct kmem_cache *sctp_bucket_cachep __read_mostly;
64 
65 long sysctl_sctp_mem[3];
66 int sysctl_sctp_rmem[3];
67 int sysctl_sctp_wmem[3];
68 
69 /* Private helper to extract ipv4 address and stash them in
70  * the protocol structure.
71  */
72 static void sctp_v4_copy_addrlist(struct list_head *addrlist,
73 				  struct net_device *dev)
74 {
75 	struct in_device *in_dev;
76 	struct in_ifaddr *ifa;
77 	struct sctp_sockaddr_entry *addr;
78 
79 	rcu_read_lock();
80 	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
81 		rcu_read_unlock();
82 		return;
83 	}
84 
85 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
86 		/* Add the address to the local list.  */
87 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
88 		if (addr) {
89 			addr->a.v4.sin_family = AF_INET;
90 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
91 			addr->valid = 1;
92 			INIT_LIST_HEAD(&addr->list);
93 			list_add_tail(&addr->list, addrlist);
94 		}
95 	}
96 
97 	rcu_read_unlock();
98 }
99 
100 /* Extract our IP addresses from the system and stash them in the
101  * protocol structure.
102  */
103 static void sctp_get_local_addr_list(struct net *net)
104 {
105 	struct net_device *dev;
106 	struct list_head *pos;
107 	struct sctp_af *af;
108 
109 	rcu_read_lock();
110 	for_each_netdev_rcu(net, dev) {
111 		list_for_each(pos, &sctp_address_families) {
112 			af = list_entry(pos, struct sctp_af, list);
113 			af->copy_addrlist(&net->sctp.local_addr_list, dev);
114 		}
115 	}
116 	rcu_read_unlock();
117 }
118 
119 /* Free the existing local addresses.  */
120 static void sctp_free_local_addr_list(struct net *net)
121 {
122 	struct sctp_sockaddr_entry *addr;
123 	struct list_head *pos, *temp;
124 
125 	list_for_each_safe(pos, temp, &net->sctp.local_addr_list) {
126 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
127 		list_del(pos);
128 		kfree(addr);
129 	}
130 }
131 
132 /* Copy the local addresses which are valid for 'scope' into 'bp'.  */
133 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
134 			      enum sctp_scope scope, gfp_t gfp, int copy_flags)
135 {
136 	struct sctp_sockaddr_entry *addr;
137 	union sctp_addr laddr;
138 	int error = 0;
139 
140 	rcu_read_lock();
141 	list_for_each_entry_rcu(addr, &net->sctp.local_addr_list, list) {
142 		if (!addr->valid)
143 			continue;
144 		if (!sctp_in_scope(net, &addr->a, scope))
145 			continue;
146 
147 		/* Now that the address is in scope, check to see if
148 		 * the address type is really supported by the local
149 		 * sock as well as the remote peer.
150 		 */
151 		if (addr->a.sa.sa_family == AF_INET &&
152 		    (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
153 		     !(copy_flags & SCTP_ADDR4_PEERSUPP)))
154 			continue;
155 		if (addr->a.sa.sa_family == AF_INET6 &&
156 		    (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
157 		     !(copy_flags & SCTP_ADDR6_PEERSUPP)))
158 			continue;
159 
160 		laddr = addr->a;
161 		/* also works for setting ipv6 address port */
162 		laddr.v4.sin_port = htons(bp->port);
163 		if (sctp_bind_addr_state(bp, &laddr) != -1)
164 			continue;
165 
166 		error = sctp_add_bind_addr(bp, &addr->a, sizeof(addr->a),
167 					   SCTP_ADDR_SRC, GFP_ATOMIC);
168 		if (error)
169 			break;
170 	}
171 
172 	rcu_read_unlock();
173 	return error;
174 }
175 
176 /* Copy over any ip options */
177 static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
178 {
179 	struct inet_sock *newinet, *inet = inet_sk(sk);
180 	struct ip_options_rcu *inet_opt, *newopt = NULL;
181 
182 	newinet = inet_sk(newsk);
183 
184 	rcu_read_lock();
185 	inet_opt = rcu_dereference(inet->inet_opt);
186 	if (inet_opt) {
187 		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
188 				      inet_opt->opt.optlen, GFP_ATOMIC);
189 		if (newopt)
190 			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
191 			       inet_opt->opt.optlen);
192 		else
193 			pr_err("%s: Failed to copy ip options\n", __func__);
194 	}
195 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
196 	rcu_read_unlock();
197 }
198 
199 /* Account for the IP options */
200 static int sctp_v4_ip_options_len(struct sock *sk)
201 {
202 	struct inet_sock *inet = inet_sk(sk);
203 	struct ip_options_rcu *inet_opt;
204 	int len = 0;
205 
206 	rcu_read_lock();
207 	inet_opt = rcu_dereference(inet->inet_opt);
208 	if (inet_opt)
209 		len = inet_opt->opt.optlen;
210 
211 	rcu_read_unlock();
212 	return len;
213 }
214 
215 /* Initialize a sctp_addr from in incoming skb.  */
216 static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
217 			     int is_saddr)
218 {
219 	/* Always called on head skb, so this is safe */
220 	struct sctphdr *sh = sctp_hdr(skb);
221 	struct sockaddr_in *sa = &addr->v4;
222 
223 	addr->v4.sin_family = AF_INET;
224 
225 	if (is_saddr) {
226 		sa->sin_port = sh->source;
227 		sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
228 	} else {
229 		sa->sin_port = sh->dest;
230 		sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
231 	}
232 	memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
233 }
234 
235 /* Initialize an sctp_addr from a socket. */
236 static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
237 {
238 	addr->v4.sin_family = AF_INET;
239 	addr->v4.sin_port = 0;
240 	addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
241 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
242 }
243 
244 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
245 static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
246 {
247 	inet_sk(sk)->inet_rcv_saddr = addr->v4.sin_addr.s_addr;
248 }
249 
250 /* Initialize sk->sk_daddr from sctp_addr. */
251 static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
252 {
253 	inet_sk(sk)->inet_daddr = addr->v4.sin_addr.s_addr;
254 }
255 
256 /* Initialize a sctp_addr from an address parameter. */
257 static bool sctp_v4_from_addr_param(union sctp_addr *addr,
258 				    union sctp_addr_param *param,
259 				    __be16 port, int iif)
260 {
261 	if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
262 		return false;
263 
264 	addr->v4.sin_family = AF_INET;
265 	addr->v4.sin_port = port;
266 	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
267 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
268 
269 	return true;
270 }
271 
272 /* Initialize an address parameter from a sctp_addr and return the length
273  * of the address parameter.
274  */
275 static int sctp_v4_to_addr_param(const union sctp_addr *addr,
276 				 union sctp_addr_param *param)
277 {
278 	int length = sizeof(struct sctp_ipv4addr_param);
279 
280 	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
281 	param->v4.param_hdr.length = htons(length);
282 	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;
283 
284 	return length;
285 }
286 
287 /* Initialize a sctp_addr from a dst_entry. */
288 static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct flowi4 *fl4,
289 			      __be16 port)
290 {
291 	saddr->v4.sin_family = AF_INET;
292 	saddr->v4.sin_port = port;
293 	saddr->v4.sin_addr.s_addr = fl4->saddr;
294 	memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
295 }
296 
297 /* Compare two addresses exactly. */
298 static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
299 			    const union sctp_addr *addr2)
300 {
301 	if (addr1->sa.sa_family != addr2->sa.sa_family)
302 		return 0;
303 	if (addr1->v4.sin_port != addr2->v4.sin_port)
304 		return 0;
305 	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
306 		return 0;
307 
308 	return 1;
309 }
310 
311 /* Initialize addr struct to INADDR_ANY. */
312 static void sctp_v4_inaddr_any(union sctp_addr *addr, __be16 port)
313 {
314 	addr->v4.sin_family = AF_INET;
315 	addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
316 	addr->v4.sin_port = port;
317 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
318 }
319 
320 /* Is this a wildcard address? */
321 static int sctp_v4_is_any(const union sctp_addr *addr)
322 {
323 	return htonl(INADDR_ANY) == addr->v4.sin_addr.s_addr;
324 }
325 
326 /* This function checks if the address is a valid address to be used for
327  * SCTP binding.
328  *
329  * Output:
330  * Return 0 - If the address is a non-unicast or an illegal address.
331  * Return 1 - If the address is a unicast.
332  */
333 static int sctp_v4_addr_valid(union sctp_addr *addr,
334 			      struct sctp_sock *sp,
335 			      const struct sk_buff *skb)
336 {
337 	/* IPv4 addresses not allowed */
338 	if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
339 		return 0;
340 
341 	/* Is this a non-unicast address or a unusable SCTP address? */
342 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr))
343 		return 0;
344 
345 	/* Is this a broadcast address? */
346 	if (skb && skb_rtable(skb)->rt_flags & RTCF_BROADCAST)
347 		return 0;
348 
349 	return 1;
350 }
351 
352 /* Should this be available for binding?   */
353 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
354 {
355 	struct sock *sk = &sp->inet.sk;
356 	struct net *net = sock_net(sk);
357 	int tb_id = RT_TABLE_LOCAL;
358 	int ret;
359 
360 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
361 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
362 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
363 	   ret != RTN_LOCAL &&
364 	   !inet_test_bit(FREEBIND, sk) &&
365 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
366 		return 0;
367 
368 	if (ipv6_only_sock(sctp_opt2sk(sp)))
369 		return 0;
370 
371 	return 1;
372 }
373 
374 /* Checking the loopback, private and other address scopes as defined in
375  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
376  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
377  *
378  * Level 0 - unusable SCTP addresses
379  * Level 1 - loopback address
380  * Level 2 - link-local addresses
381  * Level 3 - private addresses.
382  * Level 4 - global addresses
383  * For INIT and INIT-ACK address list, let L be the level of
384  * requested destination address, sender and receiver
385  * SHOULD include all of its addresses with level greater
386  * than or equal to L.
387  *
388  * IPv4 scoping can be controlled through sysctl option
389  * net.sctp.addr_scope_policy
390  */
391 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
392 {
393 	enum sctp_scope retval;
394 
395 	/* Check for unusable SCTP addresses. */
396 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
397 		retval =  SCTP_SCOPE_UNUSABLE;
398 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
399 		retval = SCTP_SCOPE_LOOPBACK;
400 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
401 		retval = SCTP_SCOPE_LINK;
402 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
403 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
404 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
405 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
406 		retval = SCTP_SCOPE_PRIVATE;
407 	} else {
408 		retval = SCTP_SCOPE_GLOBAL;
409 	}
410 
411 	return retval;
412 }
413 
414 /* Returns a valid dst cache entry for the given source and destination ip
415  * addresses. If an association is passed, trys to get a dst entry with a
416  * source address that matches an address in the bind address list.
417  */
418 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
419 				struct flowi *fl, struct sock *sk)
420 {
421 	struct sctp_association *asoc = t->asoc;
422 	struct rtable *rt;
423 	struct flowi _fl;
424 	struct flowi4 *fl4 = &_fl.u.ip4;
425 	struct sctp_bind_addr *bp;
426 	struct sctp_sockaddr_entry *laddr;
427 	struct dst_entry *dst = NULL;
428 	union sctp_addr *daddr = &t->ipaddr;
429 	union sctp_addr dst_saddr;
430 	u8 tos = READ_ONCE(inet_sk(sk)->tos);
431 
432 	if (t->dscp & SCTP_DSCP_SET_MASK)
433 		tos = t->dscp & SCTP_DSCP_VAL_MASK;
434 	memset(&_fl, 0x0, sizeof(_fl));
435 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
436 	fl4->fl4_dport = daddr->v4.sin_port;
437 	fl4->flowi4_proto = IPPROTO_SCTP;
438 	if (asoc) {
439 		fl4->flowi4_tos = tos & INET_DSCP_MASK;
440 		fl4->flowi4_scope = ip_sock_rt_scope(asoc->base.sk);
441 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
442 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
443 	}
444 	if (saddr) {
445 		fl4->saddr = saddr->v4.sin_addr.s_addr;
446 		if (!fl4->fl4_sport)
447 			fl4->fl4_sport = saddr->v4.sin_port;
448 	}
449 
450 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
451 		 &fl4->saddr);
452 
453 	rt = ip_route_output_key(sock_net(sk), fl4);
454 	if (!IS_ERR(rt)) {
455 		dst = &rt->dst;
456 		t->dst = dst;
457 		memcpy(fl, &_fl, sizeof(_fl));
458 	}
459 
460 	/* If there is no association or if a source address is passed, no
461 	 * more validation is required.
462 	 */
463 	if (!asoc || saddr)
464 		goto out;
465 
466 	bp = &asoc->base.bind_addr;
467 
468 	if (dst) {
469 		/* Walk through the bind address list and look for a bind
470 		 * address that matches the source address of the returned dst.
471 		 */
472 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
473 		rcu_read_lock();
474 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
475 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
476 			    (laddr->state != SCTP_ADDR_SRC &&
477 			    !asoc->src_out_of_asoc_ok))
478 				continue;
479 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
480 				goto out_unlock;
481 		}
482 		rcu_read_unlock();
483 
484 		/* None of the bound addresses match the source address of the
485 		 * dst. So release it.
486 		 */
487 		dst_release(dst);
488 		dst = NULL;
489 	}
490 
491 	/* Walk through the bind address list and try to get a dst that
492 	 * matches a bind address as the source address.
493 	 */
494 	rcu_read_lock();
495 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
496 		struct net_device *odev;
497 
498 		if (!laddr->valid)
499 			continue;
500 		if (laddr->state != SCTP_ADDR_SRC ||
501 		    AF_INET != laddr->a.sa.sa_family)
502 			continue;
503 
504 		fl4->fl4_sport = laddr->a.v4.sin_port;
505 		flowi4_update_output(fl4, asoc->base.sk->sk_bound_dev_if,
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 = dst_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 	if (newsk->sk_prot->init(newsk)) {
605 		sk_common_release(newsk);
606 		newsk = NULL;
607 	}
608 
609 out:
610 	return newsk;
611 }
612 
613 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
614 {
615 	/* No address mapping for V4 sockets */
616 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
617 	return sizeof(struct sockaddr_in);
618 }
619 
620 /* Dump the v4 addr to the seq file. */
621 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
622 {
623 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
624 }
625 
626 static void sctp_v4_ecn_capable(struct sock *sk)
627 {
628 	INET_ECN_xmit(sk);
629 }
630 
631 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
632 {
633 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
634 	struct sctp_sockaddr_entry *addrw, *temp;
635 	struct sctp_sock *sp;
636 
637 	spin_lock_bh(&net->sctp.addr_wq_lock);
638 
639 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
640 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
641 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
642 			 addrw->state, addrw);
643 
644 #if IS_ENABLED(CONFIG_IPV6)
645 		/* Now we send an ASCONF for each association */
646 		/* Note. we currently don't handle link local IPv6 addressees */
647 		if (addrw->a.sa.sa_family == AF_INET6) {
648 			struct in6_addr *in6;
649 
650 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
651 			    IPV6_ADDR_LINKLOCAL)
652 				goto free_next;
653 
654 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
655 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
656 			    addrw->state == SCTP_ADDR_NEW) {
657 				unsigned long timeo_val;
658 
659 				pr_debug("%s: this is on DAD, trying %d sec "
660 					 "later\n", __func__,
661 					 SCTP_ADDRESS_TICK_DELAY);
662 
663 				timeo_val = jiffies;
664 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
665 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
666 				break;
667 			}
668 		}
669 #endif
670 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
671 			struct sock *sk;
672 
673 			sk = sctp_opt2sk(sp);
674 			/* ignore bound-specific endpoints */
675 			if (!sctp_is_ep_boundall(sk))
676 				continue;
677 			bh_lock_sock(sk);
678 			if (sctp_asconf_mgmt(sp, addrw) < 0)
679 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
680 			bh_unlock_sock(sk);
681 		}
682 #if IS_ENABLED(CONFIG_IPV6)
683 free_next:
684 #endif
685 		list_del(&addrw->list);
686 		kfree(addrw);
687 	}
688 	spin_unlock_bh(&net->sctp.addr_wq_lock);
689 }
690 
691 static void sctp_free_addr_wq(struct net *net)
692 {
693 	struct sctp_sockaddr_entry *addrw;
694 	struct sctp_sockaddr_entry *temp;
695 
696 	spin_lock_bh(&net->sctp.addr_wq_lock);
697 	del_timer(&net->sctp.addr_wq_timer);
698 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
699 		list_del(&addrw->list);
700 		kfree(addrw);
701 	}
702 	spin_unlock_bh(&net->sctp.addr_wq_lock);
703 }
704 
705 /* lookup the entry for the same address in the addr_waitq
706  * sctp_addr_wq MUST be locked
707  */
708 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
709 					struct sctp_sockaddr_entry *addr)
710 {
711 	struct sctp_sockaddr_entry *addrw;
712 
713 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
714 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
715 			continue;
716 		if (addrw->a.sa.sa_family == AF_INET) {
717 			if (addrw->a.v4.sin_addr.s_addr ==
718 			    addr->a.v4.sin_addr.s_addr)
719 				return addrw;
720 		} else if (addrw->a.sa.sa_family == AF_INET6) {
721 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
722 			    &addr->a.v6.sin6_addr))
723 				return addrw;
724 		}
725 	}
726 	return NULL;
727 }
728 
729 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
730 {
731 	struct sctp_sockaddr_entry *addrw;
732 	unsigned long timeo_val;
733 
734 	/* first, we check if an opposite message already exist in the queue.
735 	 * If we found such message, it is removed.
736 	 * This operation is a bit stupid, but the DHCP client attaches the
737 	 * new address after a couple of addition and deletion of that address
738 	 */
739 
740 	spin_lock_bh(&net->sctp.addr_wq_lock);
741 
742 	/* Avoid searching the queue or modifying it if there are no consumers,
743 	 * as it can lead to performance degradation if addresses are modified
744 	 * en-masse.
745 	 *
746 	 * If the queue already contains some events, update it anyway to avoid
747 	 * ugly races between new sessions and new address events.
748 	 */
749 	if (list_empty(&net->sctp.auto_asconf_splist) &&
750 	    list_empty(&net->sctp.addr_waitq)) {
751 		spin_unlock_bh(&net->sctp.addr_wq_lock);
752 		return;
753 	}
754 
755 	/* Offsets existing events in addr_wq */
756 	addrw = sctp_addr_wq_lookup(net, addr);
757 	if (addrw) {
758 		if (addrw->state != cmd) {
759 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
760 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
761 				 &net->sctp.addr_waitq);
762 
763 			list_del(&addrw->list);
764 			kfree(addrw);
765 		}
766 		spin_unlock_bh(&net->sctp.addr_wq_lock);
767 		return;
768 	}
769 
770 	/* OK, we have to add the new address to the wait queue */
771 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
772 	if (addrw == NULL) {
773 		spin_unlock_bh(&net->sctp.addr_wq_lock);
774 		return;
775 	}
776 	addrw->state = cmd;
777 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
778 
779 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
780 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
781 
782 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
783 		timeo_val = jiffies;
784 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
785 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
786 	}
787 	spin_unlock_bh(&net->sctp.addr_wq_lock);
788 }
789 
790 /* Event handler for inet address addition/deletion events.
791  * The sctp_local_addr_list needs to be protocted by a spin lock since
792  * multiple notifiers (say IPv4 and IPv6) may be running at the same
793  * time and thus corrupt the list.
794  * The reader side is protected with RCU.
795  */
796 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
797 			       void *ptr)
798 {
799 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
800 	struct sctp_sockaddr_entry *addr = NULL;
801 	struct sctp_sockaddr_entry *temp;
802 	struct net *net = dev_net(ifa->ifa_dev->dev);
803 	int found = 0;
804 
805 	switch (ev) {
806 	case NETDEV_UP:
807 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
808 		if (addr) {
809 			addr->a.v4.sin_family = AF_INET;
810 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
811 			addr->valid = 1;
812 			spin_lock_bh(&net->sctp.local_addr_lock);
813 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
814 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
815 			spin_unlock_bh(&net->sctp.local_addr_lock);
816 		}
817 		break;
818 	case NETDEV_DOWN:
819 		spin_lock_bh(&net->sctp.local_addr_lock);
820 		list_for_each_entry_safe(addr, temp,
821 					&net->sctp.local_addr_list, list) {
822 			if (addr->a.sa.sa_family == AF_INET &&
823 					addr->a.v4.sin_addr.s_addr ==
824 					ifa->ifa_local) {
825 				found = 1;
826 				addr->valid = 0;
827 				list_del_rcu(&addr->list);
828 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
829 				break;
830 			}
831 		}
832 		spin_unlock_bh(&net->sctp.local_addr_lock);
833 		if (found)
834 			kfree_rcu(addr, rcu);
835 		break;
836 	}
837 
838 	return NOTIFY_DONE;
839 }
840 
841 /*
842  * Initialize the control inode/socket with a control endpoint data
843  * structure.  This endpoint is reserved exclusively for the OOTB processing.
844  */
845 static int sctp_ctl_sock_init(struct net *net)
846 {
847 	int err;
848 	sa_family_t family = PF_INET;
849 
850 	if (sctp_get_pf_specific(PF_INET6))
851 		family = PF_INET6;
852 
853 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
854 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
855 
856 	/* If IPv6 socket could not be created, try the IPv4 socket */
857 	if (err < 0 && family == PF_INET6)
858 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
859 					   SOCK_SEQPACKET, IPPROTO_SCTP,
860 					   net);
861 
862 	if (err < 0) {
863 		pr_err("Failed to create the SCTP control socket\n");
864 		return err;
865 	}
866 	return 0;
867 }
868 
869 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
870 {
871 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
872 
873 	skb_set_transport_header(skb, sizeof(struct udphdr));
874 	sctp_rcv(skb);
875 	return 0;
876 }
877 
878 int sctp_udp_sock_start(struct net *net)
879 {
880 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
881 	struct udp_port_cfg udp_conf = {0};
882 	struct socket *sock;
883 	int err;
884 
885 	udp_conf.family = AF_INET;
886 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
887 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
888 	err = udp_sock_create(net, &udp_conf, &sock);
889 	if (err) {
890 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
891 		return err;
892 	}
893 
894 	tuncfg.encap_type = 1;
895 	tuncfg.encap_rcv = sctp_udp_rcv;
896 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
897 	setup_udp_tunnel_sock(net, sock, &tuncfg);
898 	net->sctp.udp4_sock = sock->sk;
899 
900 #if IS_ENABLED(CONFIG_IPV6)
901 	memset(&udp_conf, 0, sizeof(udp_conf));
902 
903 	udp_conf.family = AF_INET6;
904 	udp_conf.local_ip6 = in6addr_any;
905 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
906 	udp_conf.use_udp6_rx_checksums = true;
907 	udp_conf.ipv6_v6only = true;
908 	err = udp_sock_create(net, &udp_conf, &sock);
909 	if (err) {
910 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
911 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
912 		net->sctp.udp4_sock = NULL;
913 		return err;
914 	}
915 
916 	tuncfg.encap_type = 1;
917 	tuncfg.encap_rcv = sctp_udp_rcv;
918 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
919 	setup_udp_tunnel_sock(net, sock, &tuncfg);
920 	net->sctp.udp6_sock = sock->sk;
921 #endif
922 
923 	return 0;
924 }
925 
926 void sctp_udp_sock_stop(struct net *net)
927 {
928 	if (net->sctp.udp4_sock) {
929 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
930 		net->sctp.udp4_sock = NULL;
931 	}
932 	if (net->sctp.udp6_sock) {
933 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
934 		net->sctp.udp6_sock = NULL;
935 	}
936 }
937 
938 /* Register address family specific functions. */
939 int sctp_register_af(struct sctp_af *af)
940 {
941 	switch (af->sa_family) {
942 	case AF_INET:
943 		if (sctp_af_v4_specific)
944 			return 0;
945 		sctp_af_v4_specific = af;
946 		break;
947 	case AF_INET6:
948 		if (sctp_af_v6_specific)
949 			return 0;
950 		sctp_af_v6_specific = af;
951 		break;
952 	default:
953 		return 0;
954 	}
955 
956 	INIT_LIST_HEAD(&af->list);
957 	list_add_tail(&af->list, &sctp_address_families);
958 	return 1;
959 }
960 
961 /* Get the table of functions for manipulating a particular address
962  * family.
963  */
964 struct sctp_af *sctp_get_af_specific(sa_family_t family)
965 {
966 	switch (family) {
967 	case AF_INET:
968 		return sctp_af_v4_specific;
969 	case AF_INET6:
970 		return sctp_af_v6_specific;
971 	default:
972 		return NULL;
973 	}
974 }
975 
976 /* Common code to initialize a AF_INET msg_name. */
977 static void sctp_inet_msgname(char *msgname, int *addr_len)
978 {
979 	struct sockaddr_in *sin;
980 
981 	sin = (struct sockaddr_in *)msgname;
982 	*addr_len = sizeof(struct sockaddr_in);
983 	sin->sin_family = AF_INET;
984 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
985 }
986 
987 /* Copy the primary address of the peer primary address as the msg_name. */
988 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
989 				    int *addr_len)
990 {
991 	struct sockaddr_in *sin, *sinfrom;
992 
993 	if (msgname) {
994 		struct sctp_association *asoc;
995 
996 		asoc = event->asoc;
997 		sctp_inet_msgname(msgname, addr_len);
998 		sin = (struct sockaddr_in *)msgname;
999 		sinfrom = &asoc->peer.primary_addr.v4;
1000 		sin->sin_port = htons(asoc->peer.port);
1001 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
1002 	}
1003 }
1004 
1005 /* Initialize and copy out a msgname from an inbound skb. */
1006 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
1007 {
1008 	if (msgname) {
1009 		struct sctphdr *sh = sctp_hdr(skb);
1010 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
1011 
1012 		sctp_inet_msgname(msgname, len);
1013 		sin->sin_port = sh->source;
1014 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1015 	}
1016 }
1017 
1018 /* Do we support this AF? */
1019 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1020 {
1021 	/* PF_INET only supports AF_INET addresses. */
1022 	return AF_INET == family;
1023 }
1024 
1025 /* Address matching with wildcards allowed. */
1026 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1027 			      const union sctp_addr *addr2,
1028 			      struct sctp_sock *opt)
1029 {
1030 	/* PF_INET only supports AF_INET addresses. */
1031 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1032 		return 0;
1033 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1034 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1035 		return 1;
1036 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1037 		return 1;
1038 
1039 	return 0;
1040 }
1041 
1042 /* Verify that provided sockaddr looks bindable.  Common verification has
1043  * already been taken care of.
1044  */
1045 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1046 {
1047 	return sctp_v4_available(addr, opt);
1048 }
1049 
1050 /* Verify that sockaddr looks sendable.  Common verification has already
1051  * been taken care of.
1052  */
1053 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1054 {
1055 	return 1;
1056 }
1057 
1058 /* Fill in Supported Address Type information for INIT and INIT-ACK
1059  * chunks.  Returns number of addresses supported.
1060  */
1061 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1062 				     __be16 *types)
1063 {
1064 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1065 	return 1;
1066 }
1067 
1068 /* Wrapper routine that calls the ip transmit routine. */
1069 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1070 {
1071 	struct dst_entry *dst = dst_clone(t->dst);
1072 	struct flowi4 *fl4 = &t->fl.u.ip4;
1073 	struct sock *sk = skb->sk;
1074 	struct inet_sock *inet = inet_sk(sk);
1075 	__u8 dscp = READ_ONCE(inet->tos);
1076 	__be16 df = 0;
1077 
1078 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1079 		 skb->len, &fl4->saddr, &fl4->daddr);
1080 
1081 	if (t->dscp & SCTP_DSCP_SET_MASK)
1082 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1083 
1084 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1085 							   : IP_PMTUDISC_DONT;
1086 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1087 
1088 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1089 		skb_dst_set(skb, dst);
1090 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1091 	}
1092 
1093 	if (skb_is_gso(skb))
1094 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1095 
1096 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1097 		df = htons(IP_DF);
1098 
1099 	skb->encapsulation = 1;
1100 	skb_reset_inner_mac_header(skb);
1101 	skb_reset_inner_transport_header(skb);
1102 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1103 	udp_tunnel_xmit_skb(dst_rtable(dst), sk, skb, fl4->saddr,
1104 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1105 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1106 	return 0;
1107 }
1108 
1109 static struct sctp_af sctp_af_inet;
1110 
1111 static struct sctp_pf sctp_pf_inet = {
1112 	.event_msgname = sctp_inet_event_msgname,
1113 	.skb_msgname   = sctp_inet_skb_msgname,
1114 	.af_supported  = sctp_inet_af_supported,
1115 	.cmp_addr      = sctp_inet_cmp_addr,
1116 	.bind_verify   = sctp_inet_bind_verify,
1117 	.send_verify   = sctp_inet_send_verify,
1118 	.supported_addrs = sctp_inet_supported_addrs,
1119 	.create_accept_sk = sctp_v4_create_accept_sk,
1120 	.addr_to_user  = sctp_v4_addr_to_user,
1121 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1122 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1123 	.copy_ip_options = sctp_v4_copy_ip_options,
1124 	.af            = &sctp_af_inet
1125 };
1126 
1127 /* Notifier for inetaddr addition/deletion events.  */
1128 static struct notifier_block sctp_inetaddr_notifier = {
1129 	.notifier_call = sctp_inetaddr_event,
1130 };
1131 
1132 /* Socket operations.  */
1133 static const struct proto_ops inet_seqpacket_ops = {
1134 	.family		   = PF_INET,
1135 	.owner		   = THIS_MODULE,
1136 	.release	   = inet_release,	/* Needs to be wrapped... */
1137 	.bind		   = inet_bind,
1138 	.connect	   = sctp_inet_connect,
1139 	.socketpair	   = sock_no_socketpair,
1140 	.accept		   = inet_accept,
1141 	.getname	   = inet_getname,	/* Semantics are different.  */
1142 	.poll		   = sctp_poll,
1143 	.ioctl		   = inet_ioctl,
1144 	.gettstamp	   = sock_gettstamp,
1145 	.listen		   = sctp_inet_listen,
1146 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1147 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1148 	.getsockopt	   = sock_common_getsockopt,
1149 	.sendmsg	   = inet_sendmsg,
1150 	.recvmsg	   = inet_recvmsg,
1151 	.mmap		   = sock_no_mmap,
1152 };
1153 
1154 /* Registration with AF_INET family.  */
1155 static struct inet_protosw sctp_seqpacket_protosw = {
1156 	.type       = SOCK_SEQPACKET,
1157 	.protocol   = IPPROTO_SCTP,
1158 	.prot       = &sctp_prot,
1159 	.ops        = &inet_seqpacket_ops,
1160 	.flags      = SCTP_PROTOSW_FLAG
1161 };
1162 static struct inet_protosw sctp_stream_protosw = {
1163 	.type       = SOCK_STREAM,
1164 	.protocol   = IPPROTO_SCTP,
1165 	.prot       = &sctp_prot,
1166 	.ops        = &inet_seqpacket_ops,
1167 	.flags      = SCTP_PROTOSW_FLAG
1168 };
1169 
1170 static int sctp4_rcv(struct sk_buff *skb)
1171 {
1172 	SCTP_INPUT_CB(skb)->encap_port = 0;
1173 	return sctp_rcv(skb);
1174 }
1175 
1176 /* Register with IP layer.  */
1177 static const struct net_protocol sctp_protocol = {
1178 	.handler     = sctp4_rcv,
1179 	.err_handler = sctp_v4_err,
1180 	.no_policy   = 1,
1181 	.icmp_strict_tag_validation = 1,
1182 };
1183 
1184 /* IPv4 address related functions.  */
1185 static struct sctp_af sctp_af_inet = {
1186 	.sa_family	   = AF_INET,
1187 	.sctp_xmit	   = sctp_v4_xmit,
1188 	.setsockopt	   = ip_setsockopt,
1189 	.getsockopt	   = ip_getsockopt,
1190 	.get_dst	   = sctp_v4_get_dst,
1191 	.get_saddr	   = sctp_v4_get_saddr,
1192 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1193 	.from_skb	   = sctp_v4_from_skb,
1194 	.from_sk	   = sctp_v4_from_sk,
1195 	.from_addr_param   = sctp_v4_from_addr_param,
1196 	.to_addr_param	   = sctp_v4_to_addr_param,
1197 	.cmp_addr	   = sctp_v4_cmp_addr,
1198 	.addr_valid	   = sctp_v4_addr_valid,
1199 	.inaddr_any	   = sctp_v4_inaddr_any,
1200 	.is_any		   = sctp_v4_is_any,
1201 	.available	   = sctp_v4_available,
1202 	.scope		   = sctp_v4_scope,
1203 	.skb_iif	   = sctp_v4_skb_iif,
1204 	.skb_sdif	   = sctp_v4_skb_sdif,
1205 	.is_ce		   = sctp_v4_is_ce,
1206 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1207 	.ecn_capable	   = sctp_v4_ecn_capable,
1208 	.net_header_len	   = sizeof(struct iphdr),
1209 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1210 	.ip_options_len	   = sctp_v4_ip_options_len,
1211 };
1212 
1213 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1214 {
1215 	switch (family) {
1216 	case PF_INET:
1217 		return sctp_pf_inet_specific;
1218 	case PF_INET6:
1219 		return sctp_pf_inet6_specific;
1220 	default:
1221 		return NULL;
1222 	}
1223 }
1224 
1225 /* Register the PF specific function table.  */
1226 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1227 {
1228 	switch (family) {
1229 	case PF_INET:
1230 		if (sctp_pf_inet_specific)
1231 			return 0;
1232 		sctp_pf_inet_specific = pf;
1233 		break;
1234 	case PF_INET6:
1235 		if (sctp_pf_inet6_specific)
1236 			return 0;
1237 		sctp_pf_inet6_specific = pf;
1238 		break;
1239 	default:
1240 		return 0;
1241 	}
1242 	return 1;
1243 }
1244 
1245 static inline int init_sctp_mibs(struct net *net)
1246 {
1247 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1248 	if (!net->sctp.sctp_statistics)
1249 		return -ENOMEM;
1250 	return 0;
1251 }
1252 
1253 static inline void cleanup_sctp_mibs(struct net *net)
1254 {
1255 	free_percpu(net->sctp.sctp_statistics);
1256 }
1257 
1258 static void sctp_v4_pf_init(void)
1259 {
1260 	/* Initialize the SCTP specific PF functions. */
1261 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1262 	sctp_register_af(&sctp_af_inet);
1263 }
1264 
1265 static void sctp_v4_pf_exit(void)
1266 {
1267 	list_del(&sctp_af_inet.list);
1268 }
1269 
1270 static int sctp_v4_protosw_init(void)
1271 {
1272 	int rc;
1273 
1274 	rc = proto_register(&sctp_prot, 1);
1275 	if (rc)
1276 		return rc;
1277 
1278 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1279 	inet_register_protosw(&sctp_seqpacket_protosw);
1280 	inet_register_protosw(&sctp_stream_protosw);
1281 
1282 	return 0;
1283 }
1284 
1285 static void sctp_v4_protosw_exit(void)
1286 {
1287 	inet_unregister_protosw(&sctp_stream_protosw);
1288 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1289 	proto_unregister(&sctp_prot);
1290 }
1291 
1292 static int sctp_v4_add_protocol(void)
1293 {
1294 	/* Register notifier for inet address additions/deletions. */
1295 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1296 
1297 	/* Register SCTP with inet layer.  */
1298 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1299 		return -EAGAIN;
1300 
1301 	return 0;
1302 }
1303 
1304 static void sctp_v4_del_protocol(void)
1305 {
1306 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1307 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1308 }
1309 
1310 static int __net_init sctp_defaults_init(struct net *net)
1311 {
1312 	int status;
1313 
1314 	/*
1315 	 * 14. Suggested SCTP Protocol Parameter Values
1316 	 */
1317 	/* The following protocol parameters are RECOMMENDED:  */
1318 	/* RTO.Initial              - 3  seconds */
1319 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1320 	/* RTO.Min                  - 1  second */
1321 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1322 	/* RTO.Max                 -  60 seconds */
1323 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1324 	/* RTO.Alpha                - 1/8 */
1325 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1326 	/* RTO.Beta                 - 1/4 */
1327 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1328 
1329 	/* Valid.Cookie.Life        - 60  seconds */
1330 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1331 
1332 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1333 	net->sctp.cookie_preserve_enable 	= 1;
1334 
1335 	/* Default sctp sockets to use md5 as their hmac alg */
1336 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1337 	net->sctp.sctp_hmac_alg			= "md5";
1338 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1339 	net->sctp.sctp_hmac_alg			= "sha1";
1340 #else
1341 	net->sctp.sctp_hmac_alg			= NULL;
1342 #endif
1343 
1344 	/* Max.Burst		    - 4 */
1345 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1346 
1347 	/* Disable of Primary Path Switchover by default */
1348 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1349 
1350 	/* Enable pf state by default */
1351 	net->sctp.pf_enable = 1;
1352 
1353 	/* Ignore pf exposure feature by default */
1354 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1355 
1356 	/* Association.Max.Retrans  - 10 attempts
1357 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1358 	 * Max.Init.Retransmits     - 8  attempts
1359 	 */
1360 	net->sctp.max_retrans_association	= 10;
1361 	net->sctp.max_retrans_path		= 5;
1362 	net->sctp.max_retrans_init		= 8;
1363 
1364 	/* Sendbuffer growth	    - do per-socket accounting */
1365 	net->sctp.sndbuf_policy			= 0;
1366 
1367 	/* Rcvbuffer growth	    - do per-socket accounting */
1368 	net->sctp.rcvbuf_policy			= 0;
1369 
1370 	/* HB.interval              - 30 seconds */
1371 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1372 
1373 	/* delayed SACK timeout */
1374 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1375 
1376 	/* Disable ADDIP by default. */
1377 	net->sctp.addip_enable = 0;
1378 	net->sctp.addip_noauth = 0;
1379 	net->sctp.default_auto_asconf = 0;
1380 
1381 	/* Enable PR-SCTP by default. */
1382 	net->sctp.prsctp_enable = 1;
1383 
1384 	/* Disable RECONF by default. */
1385 	net->sctp.reconf_enable = 0;
1386 
1387 	/* Disable AUTH by default. */
1388 	net->sctp.auth_enable = 0;
1389 
1390 	/* Enable ECN by default. */
1391 	net->sctp.ecn_enable = 1;
1392 
1393 	/* Set UDP tunneling listening port to 0 by default */
1394 	net->sctp.udp_port = 0;
1395 
1396 	/* Set remote encap port to 0 by default */
1397 	net->sctp.encap_port = 0;
1398 
1399 	/* Set SCOPE policy to enabled */
1400 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1401 
1402 	/* Set the default rwnd update threshold */
1403 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1404 
1405 	/* Initialize maximum autoclose timeout. */
1406 	net->sctp.max_autoclose		= INT_MAX / HZ;
1407 
1408 #ifdef CONFIG_NET_L3_MASTER_DEV
1409 	net->sctp.l3mdev_accept = 1;
1410 #endif
1411 
1412 	status = sctp_sysctl_net_register(net);
1413 	if (status)
1414 		goto err_sysctl_register;
1415 
1416 	/* Allocate and initialise sctp mibs.  */
1417 	status = init_sctp_mibs(net);
1418 	if (status)
1419 		goto err_init_mibs;
1420 
1421 #ifdef CONFIG_PROC_FS
1422 	/* Initialize proc fs directory.  */
1423 	status = sctp_proc_init(net);
1424 	if (status)
1425 		goto err_init_proc;
1426 #endif
1427 
1428 	sctp_dbg_objcnt_init(net);
1429 
1430 	/* Initialize the local address list. */
1431 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1432 	spin_lock_init(&net->sctp.local_addr_lock);
1433 	sctp_get_local_addr_list(net);
1434 
1435 	/* Initialize the address event list */
1436 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1437 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1438 	spin_lock_init(&net->sctp.addr_wq_lock);
1439 	net->sctp.addr_wq_timer.expires = 0;
1440 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1441 
1442 	return 0;
1443 
1444 #ifdef CONFIG_PROC_FS
1445 err_init_proc:
1446 	cleanup_sctp_mibs(net);
1447 #endif
1448 err_init_mibs:
1449 	sctp_sysctl_net_unregister(net);
1450 err_sysctl_register:
1451 	return status;
1452 }
1453 
1454 static void __net_exit sctp_defaults_exit(struct net *net)
1455 {
1456 	/* Free the local address list */
1457 	sctp_free_addr_wq(net);
1458 	sctp_free_local_addr_list(net);
1459 
1460 #ifdef CONFIG_PROC_FS
1461 	remove_proc_subtree("sctp", net->proc_net);
1462 	net->sctp.proc_net_sctp = NULL;
1463 #endif
1464 	cleanup_sctp_mibs(net);
1465 	sctp_sysctl_net_unregister(net);
1466 }
1467 
1468 static struct pernet_operations sctp_defaults_ops = {
1469 	.init = sctp_defaults_init,
1470 	.exit = sctp_defaults_exit,
1471 };
1472 
1473 static int __net_init sctp_ctrlsock_init(struct net *net)
1474 {
1475 	int status;
1476 
1477 	/* Initialize the control inode/socket for handling OOTB packets.  */
1478 	status = sctp_ctl_sock_init(net);
1479 	if (status)
1480 		pr_err("Failed to initialize the SCTP control sock\n");
1481 
1482 	return status;
1483 }
1484 
1485 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1486 {
1487 	/* Free the control endpoint.  */
1488 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1489 }
1490 
1491 static struct pernet_operations sctp_ctrlsock_ops = {
1492 	.init = sctp_ctrlsock_init,
1493 	.exit = sctp_ctrlsock_exit,
1494 };
1495 
1496 /* Initialize the universe into something sensible.  */
1497 static __init int sctp_init(void)
1498 {
1499 	unsigned long nr_pages = totalram_pages();
1500 	unsigned long limit;
1501 	unsigned long goal;
1502 	int max_entry_order;
1503 	int num_entries;
1504 	int max_share;
1505 	int status;
1506 	int order;
1507 	int i;
1508 
1509 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1510 
1511 	/* Allocate bind_bucket and chunk caches. */
1512 	status = -ENOBUFS;
1513 	sctp_bucket_cachep = KMEM_CACHE(sctp_bind_bucket, SLAB_HWCACHE_ALIGN);
1514 	if (!sctp_bucket_cachep)
1515 		goto out;
1516 
1517 	sctp_chunk_cachep = KMEM_CACHE(sctp_chunk, SLAB_HWCACHE_ALIGN);
1518 	if (!sctp_chunk_cachep)
1519 		goto err_chunk_cachep;
1520 
1521 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1522 	if (status)
1523 		goto err_percpu_counter_init;
1524 
1525 	/* Implementation specific variables. */
1526 
1527 	/* Initialize default stream count setup information. */
1528 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1529 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1530 
1531 	/* Initialize handle used for association ids. */
1532 	idr_init(&sctp_assocs_id);
1533 
1534 	limit = nr_free_buffer_pages() / 8;
1535 	limit = max(limit, 128UL);
1536 	sysctl_sctp_mem[0] = limit / 4 * 3;
1537 	sysctl_sctp_mem[1] = limit;
1538 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1539 
1540 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1541 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1542 	max_share = min(4UL*1024*1024, limit);
1543 
1544 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1545 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1546 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1547 
1548 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1549 	sysctl_sctp_wmem[1] = 16*1024;
1550 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1551 
1552 	/* Size and allocate the association hash table.
1553 	 * The methodology is similar to that of the tcp hash tables.
1554 	 * Though not identical.  Start by getting a goal size
1555 	 */
1556 	if (nr_pages >= (128 * 1024))
1557 		goal = nr_pages >> (22 - PAGE_SHIFT);
1558 	else
1559 		goal = nr_pages >> (24 - PAGE_SHIFT);
1560 
1561 	/* Then compute the page order for said goal */
1562 	order = get_order(goal);
1563 
1564 	/* Now compute the required page order for the maximum sized table we
1565 	 * want to create
1566 	 */
1567 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1568 				    sizeof(struct sctp_bind_hashbucket));
1569 
1570 	/* Limit the page order by that maximum hash table size */
1571 	order = min(order, max_entry_order);
1572 
1573 	/* Allocate and initialize the endpoint hash table.  */
1574 	sctp_ep_hashsize = 64;
1575 	sctp_ep_hashtable =
1576 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1577 	if (!sctp_ep_hashtable) {
1578 		pr_err("Failed endpoint_hash alloc\n");
1579 		status = -ENOMEM;
1580 		goto err_ehash_alloc;
1581 	}
1582 	for (i = 0; i < sctp_ep_hashsize; i++) {
1583 		rwlock_init(&sctp_ep_hashtable[i].lock);
1584 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1585 	}
1586 
1587 	/* Allocate and initialize the SCTP port hash table.
1588 	 * Note that order is initalized to start at the max sized
1589 	 * table we want to support.  If we can't get that many pages
1590 	 * reduce the order and try again
1591 	 */
1592 	do {
1593 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1594 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1595 	} while (!sctp_port_hashtable && --order > 0);
1596 
1597 	if (!sctp_port_hashtable) {
1598 		pr_err("Failed bind hash alloc\n");
1599 		status = -ENOMEM;
1600 		goto err_bhash_alloc;
1601 	}
1602 
1603 	/* Now compute the number of entries that will fit in the
1604 	 * port hash space we allocated
1605 	 */
1606 	num_entries = (1UL << order) * PAGE_SIZE /
1607 		      sizeof(struct sctp_bind_hashbucket);
1608 
1609 	/* And finish by rounding it down to the nearest power of two.
1610 	 * This wastes some memory of course, but it's needed because
1611 	 * the hash function operates based on the assumption that
1612 	 * the number of entries is a power of two.
1613 	 */
1614 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1615 
1616 	for (i = 0; i < sctp_port_hashsize; i++) {
1617 		spin_lock_init(&sctp_port_hashtable[i].lock);
1618 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1619 	}
1620 
1621 	status = sctp_transport_hashtable_init();
1622 	if (status)
1623 		goto err_thash_alloc;
1624 
1625 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1626 		num_entries);
1627 
1628 	sctp_sysctl_register();
1629 
1630 	INIT_LIST_HEAD(&sctp_address_families);
1631 	sctp_v4_pf_init();
1632 	sctp_v6_pf_init();
1633 	sctp_sched_ops_init();
1634 
1635 	status = register_pernet_subsys(&sctp_defaults_ops);
1636 	if (status)
1637 		goto err_register_defaults;
1638 
1639 	status = sctp_v4_protosw_init();
1640 	if (status)
1641 		goto err_protosw_init;
1642 
1643 	status = sctp_v6_protosw_init();
1644 	if (status)
1645 		goto err_v6_protosw_init;
1646 
1647 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1648 	if (status)
1649 		goto err_register_ctrlsock;
1650 
1651 	status = sctp_v4_add_protocol();
1652 	if (status)
1653 		goto err_add_protocol;
1654 
1655 	/* Register SCTP with inet6 layer.  */
1656 	status = sctp_v6_add_protocol();
1657 	if (status)
1658 		goto err_v6_add_protocol;
1659 
1660 	if (sctp_offload_init() < 0)
1661 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1662 
1663 out:
1664 	return status;
1665 err_v6_add_protocol:
1666 	sctp_v4_del_protocol();
1667 err_add_protocol:
1668 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1669 err_register_ctrlsock:
1670 	sctp_v6_protosw_exit();
1671 err_v6_protosw_init:
1672 	sctp_v4_protosw_exit();
1673 err_protosw_init:
1674 	unregister_pernet_subsys(&sctp_defaults_ops);
1675 err_register_defaults:
1676 	sctp_v4_pf_exit();
1677 	sctp_v6_pf_exit();
1678 	sctp_sysctl_unregister();
1679 	free_pages((unsigned long)sctp_port_hashtable,
1680 		   get_order(sctp_port_hashsize *
1681 			     sizeof(struct sctp_bind_hashbucket)));
1682 err_bhash_alloc:
1683 	sctp_transport_hashtable_destroy();
1684 err_thash_alloc:
1685 	kfree(sctp_ep_hashtable);
1686 err_ehash_alloc:
1687 	percpu_counter_destroy(&sctp_sockets_allocated);
1688 err_percpu_counter_init:
1689 	kmem_cache_destroy(sctp_chunk_cachep);
1690 err_chunk_cachep:
1691 	kmem_cache_destroy(sctp_bucket_cachep);
1692 	goto out;
1693 }
1694 
1695 /* Exit handler for the SCTP protocol.  */
1696 static __exit void sctp_exit(void)
1697 {
1698 	/* BUG.  This should probably do something useful like clean
1699 	 * up all the remaining associations and all that memory.
1700 	 */
1701 
1702 	/* Unregister with inet6/inet layers. */
1703 	sctp_v6_del_protocol();
1704 	sctp_v4_del_protocol();
1705 
1706 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1707 
1708 	/* Free protosw registrations */
1709 	sctp_v6_protosw_exit();
1710 	sctp_v4_protosw_exit();
1711 
1712 	unregister_pernet_subsys(&sctp_defaults_ops);
1713 
1714 	/* Unregister with socket layer. */
1715 	sctp_v6_pf_exit();
1716 	sctp_v4_pf_exit();
1717 
1718 	sctp_sysctl_unregister();
1719 
1720 	free_pages((unsigned long)sctp_port_hashtable,
1721 		   get_order(sctp_port_hashsize *
1722 			     sizeof(struct sctp_bind_hashbucket)));
1723 	kfree(sctp_ep_hashtable);
1724 	sctp_transport_hashtable_destroy();
1725 
1726 	percpu_counter_destroy(&sctp_sockets_allocated);
1727 
1728 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1729 
1730 	kmem_cache_destroy(sctp_chunk_cachep);
1731 	kmem_cache_destroy(sctp_bucket_cachep);
1732 }
1733 
1734 module_init(sctp_init);
1735 module_exit(sctp_exit);
1736 
1737 /*
1738  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1739  */
1740 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1741 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1742 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1743 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1744 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1745 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1746 MODULE_LICENSE("GPL");
1747