xref: /linux/net/sctp/protocol.c (revision 3c4fc7bf4c9e66fe71abcbf93f62f4ddb89b7f15)
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 net *net = sock_net(&sp->inet.sk);
355 	int ret = inet_addr_type(net, addr->v4.sin_addr.s_addr);
356 
357 
358 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
359 	   ret != RTN_LOCAL &&
360 	   !sp->inet.freebind &&
361 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
362 		return 0;
363 
364 	if (ipv6_only_sock(sctp_opt2sk(sp)))
365 		return 0;
366 
367 	return 1;
368 }
369 
370 /* Checking the loopback, private and other address scopes as defined in
371  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
372  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
373  *
374  * Level 0 - unusable SCTP addresses
375  * Level 1 - loopback address
376  * Level 2 - link-local addresses
377  * Level 3 - private addresses.
378  * Level 4 - global addresses
379  * For INIT and INIT-ACK address list, let L be the level of
380  * requested destination address, sender and receiver
381  * SHOULD include all of its addresses with level greater
382  * than or equal to L.
383  *
384  * IPv4 scoping can be controlled through sysctl option
385  * net.sctp.addr_scope_policy
386  */
387 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
388 {
389 	enum sctp_scope retval;
390 
391 	/* Check for unusable SCTP addresses. */
392 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
393 		retval =  SCTP_SCOPE_UNUSABLE;
394 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
395 		retval = SCTP_SCOPE_LOOPBACK;
396 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
397 		retval = SCTP_SCOPE_LINK;
398 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
399 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
400 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
401 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
402 		retval = SCTP_SCOPE_PRIVATE;
403 	} else {
404 		retval = SCTP_SCOPE_GLOBAL;
405 	}
406 
407 	return retval;
408 }
409 
410 /* Returns a valid dst cache entry for the given source and destination ip
411  * addresses. If an association is passed, trys to get a dst entry with a
412  * source address that matches an address in the bind address list.
413  */
414 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
415 				struct flowi *fl, struct sock *sk)
416 {
417 	struct sctp_association *asoc = t->asoc;
418 	struct rtable *rt;
419 	struct flowi _fl;
420 	struct flowi4 *fl4 = &_fl.u.ip4;
421 	struct sctp_bind_addr *bp;
422 	struct sctp_sockaddr_entry *laddr;
423 	struct dst_entry *dst = NULL;
424 	union sctp_addr *daddr = &t->ipaddr;
425 	union sctp_addr dst_saddr;
426 	__u8 tos = inet_sk(sk)->tos;
427 
428 	if (t->dscp & SCTP_DSCP_SET_MASK)
429 		tos = t->dscp & SCTP_DSCP_VAL_MASK;
430 	memset(&_fl, 0x0, sizeof(_fl));
431 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
432 	fl4->fl4_dport = daddr->v4.sin_port;
433 	fl4->flowi4_proto = IPPROTO_SCTP;
434 	if (asoc) {
435 		fl4->flowi4_tos = RT_CONN_FLAGS_TOS(asoc->base.sk, tos);
436 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
437 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
438 	}
439 	if (saddr) {
440 		fl4->saddr = saddr->v4.sin_addr.s_addr;
441 		if (!fl4->fl4_sport)
442 			fl4->fl4_sport = saddr->v4.sin_port;
443 	}
444 
445 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
446 		 &fl4->saddr);
447 
448 	rt = ip_route_output_key(sock_net(sk), fl4);
449 	if (!IS_ERR(rt)) {
450 		dst = &rt->dst;
451 		t->dst = dst;
452 		memcpy(fl, &_fl, sizeof(_fl));
453 	}
454 
455 	/* If there is no association or if a source address is passed, no
456 	 * more validation is required.
457 	 */
458 	if (!asoc || saddr)
459 		goto out;
460 
461 	bp = &asoc->base.bind_addr;
462 
463 	if (dst) {
464 		/* Walk through the bind address list and look for a bind
465 		 * address that matches the source address of the returned dst.
466 		 */
467 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
468 		rcu_read_lock();
469 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
470 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
471 			    (laddr->state != SCTP_ADDR_SRC &&
472 			    !asoc->src_out_of_asoc_ok))
473 				continue;
474 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
475 				goto out_unlock;
476 		}
477 		rcu_read_unlock();
478 
479 		/* None of the bound addresses match the source address of the
480 		 * dst. So release it.
481 		 */
482 		dst_release(dst);
483 		dst = NULL;
484 	}
485 
486 	/* Walk through the bind address list and try to get a dst that
487 	 * matches a bind address as the source address.
488 	 */
489 	rcu_read_lock();
490 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
491 		struct net_device *odev;
492 
493 		if (!laddr->valid)
494 			continue;
495 		if (laddr->state != SCTP_ADDR_SRC ||
496 		    AF_INET != laddr->a.sa.sa_family)
497 			continue;
498 
499 		fl4->fl4_sport = laddr->a.v4.sin_port;
500 		flowi4_update_output(fl4,
501 				     asoc->base.sk->sk_bound_dev_if,
502 				     RT_CONN_FLAGS_TOS(asoc->base.sk, tos),
503 				     daddr->v4.sin_addr.s_addr,
504 				     laddr->a.v4.sin_addr.s_addr);
505 
506 		rt = ip_route_output_key(sock_net(sk), fl4);
507 		if (IS_ERR(rt))
508 			continue;
509 
510 		/* Ensure the src address belongs to the output
511 		 * interface.
512 		 */
513 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
514 				     false);
515 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
516 			if (!dst) {
517 				dst = &rt->dst;
518 				t->dst = dst;
519 				memcpy(fl, &_fl, sizeof(_fl));
520 			} else {
521 				dst_release(&rt->dst);
522 			}
523 			continue;
524 		}
525 
526 		dst_release(dst);
527 		dst = &rt->dst;
528 		t->dst = dst;
529 		memcpy(fl, &_fl, sizeof(_fl));
530 		break;
531 	}
532 
533 out_unlock:
534 	rcu_read_unlock();
535 out:
536 	if (dst) {
537 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
538 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
539 	} else {
540 		t->dst = NULL;
541 		pr_debug("no route\n");
542 	}
543 }
544 
545 /* For v4, the source address is cached in the route entry(dst). So no need
546  * to cache it separately and hence this is an empty routine.
547  */
548 static void sctp_v4_get_saddr(struct sctp_sock *sk,
549 			      struct sctp_transport *t,
550 			      struct flowi *fl)
551 {
552 	union sctp_addr *saddr = &t->saddr;
553 	struct rtable *rt = (struct rtable *)t->dst;
554 
555 	if (rt) {
556 		saddr->v4.sin_family = AF_INET;
557 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
558 	}
559 }
560 
561 /* What interface did this skb arrive on? */
562 static int sctp_v4_skb_iif(const struct sk_buff *skb)
563 {
564 	return inet_iif(skb);
565 }
566 
567 /* Was this packet marked by Explicit Congestion Notification? */
568 static int sctp_v4_is_ce(const struct sk_buff *skb)
569 {
570 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
571 }
572 
573 /* Create and initialize a new sk for the socket returned by accept(). */
574 static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
575 					     struct sctp_association *asoc,
576 					     bool kern)
577 {
578 	struct sock *newsk = sk_alloc(sock_net(sk), PF_INET, GFP_KERNEL,
579 			sk->sk_prot, kern);
580 	struct inet_sock *newinet;
581 
582 	if (!newsk)
583 		goto out;
584 
585 	sock_init_data(NULL, newsk);
586 
587 	sctp_copy_sock(newsk, sk, asoc);
588 	sock_reset_flag(newsk, SOCK_ZAPPED);
589 
590 	sctp_v4_copy_ip_options(sk, newsk);
591 
592 	newinet = inet_sk(newsk);
593 
594 	newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
595 
596 	sk_refcnt_debug_inc(newsk);
597 
598 	if (newsk->sk_prot->init(newsk)) {
599 		sk_common_release(newsk);
600 		newsk = NULL;
601 	}
602 
603 out:
604 	return newsk;
605 }
606 
607 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
608 {
609 	/* No address mapping for V4 sockets */
610 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
611 	return sizeof(struct sockaddr_in);
612 }
613 
614 /* Dump the v4 addr to the seq file. */
615 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
616 {
617 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
618 }
619 
620 static void sctp_v4_ecn_capable(struct sock *sk)
621 {
622 	INET_ECN_xmit(sk);
623 }
624 
625 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
626 {
627 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
628 	struct sctp_sockaddr_entry *addrw, *temp;
629 	struct sctp_sock *sp;
630 
631 	spin_lock_bh(&net->sctp.addr_wq_lock);
632 
633 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
634 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
635 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
636 			 addrw->state, addrw);
637 
638 #if IS_ENABLED(CONFIG_IPV6)
639 		/* Now we send an ASCONF for each association */
640 		/* Note. we currently don't handle link local IPv6 addressees */
641 		if (addrw->a.sa.sa_family == AF_INET6) {
642 			struct in6_addr *in6;
643 
644 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
645 			    IPV6_ADDR_LINKLOCAL)
646 				goto free_next;
647 
648 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
649 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
650 			    addrw->state == SCTP_ADDR_NEW) {
651 				unsigned long timeo_val;
652 
653 				pr_debug("%s: this is on DAD, trying %d sec "
654 					 "later\n", __func__,
655 					 SCTP_ADDRESS_TICK_DELAY);
656 
657 				timeo_val = jiffies;
658 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
659 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
660 				break;
661 			}
662 		}
663 #endif
664 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
665 			struct sock *sk;
666 
667 			sk = sctp_opt2sk(sp);
668 			/* ignore bound-specific endpoints */
669 			if (!sctp_is_ep_boundall(sk))
670 				continue;
671 			bh_lock_sock(sk);
672 			if (sctp_asconf_mgmt(sp, addrw) < 0)
673 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
674 			bh_unlock_sock(sk);
675 		}
676 #if IS_ENABLED(CONFIG_IPV6)
677 free_next:
678 #endif
679 		list_del(&addrw->list);
680 		kfree(addrw);
681 	}
682 	spin_unlock_bh(&net->sctp.addr_wq_lock);
683 }
684 
685 static void sctp_free_addr_wq(struct net *net)
686 {
687 	struct sctp_sockaddr_entry *addrw;
688 	struct sctp_sockaddr_entry *temp;
689 
690 	spin_lock_bh(&net->sctp.addr_wq_lock);
691 	del_timer(&net->sctp.addr_wq_timer);
692 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
693 		list_del(&addrw->list);
694 		kfree(addrw);
695 	}
696 	spin_unlock_bh(&net->sctp.addr_wq_lock);
697 }
698 
699 /* lookup the entry for the same address in the addr_waitq
700  * sctp_addr_wq MUST be locked
701  */
702 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
703 					struct sctp_sockaddr_entry *addr)
704 {
705 	struct sctp_sockaddr_entry *addrw;
706 
707 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
708 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
709 			continue;
710 		if (addrw->a.sa.sa_family == AF_INET) {
711 			if (addrw->a.v4.sin_addr.s_addr ==
712 			    addr->a.v4.sin_addr.s_addr)
713 				return addrw;
714 		} else if (addrw->a.sa.sa_family == AF_INET6) {
715 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
716 			    &addr->a.v6.sin6_addr))
717 				return addrw;
718 		}
719 	}
720 	return NULL;
721 }
722 
723 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
724 {
725 	struct sctp_sockaddr_entry *addrw;
726 	unsigned long timeo_val;
727 
728 	/* first, we check if an opposite message already exist in the queue.
729 	 * If we found such message, it is removed.
730 	 * This operation is a bit stupid, but the DHCP client attaches the
731 	 * new address after a couple of addition and deletion of that address
732 	 */
733 
734 	spin_lock_bh(&net->sctp.addr_wq_lock);
735 	/* Offsets existing events in addr_wq */
736 	addrw = sctp_addr_wq_lookup(net, addr);
737 	if (addrw) {
738 		if (addrw->state != cmd) {
739 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
740 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
741 				 &net->sctp.addr_waitq);
742 
743 			list_del(&addrw->list);
744 			kfree(addrw);
745 		}
746 		spin_unlock_bh(&net->sctp.addr_wq_lock);
747 		return;
748 	}
749 
750 	/* OK, we have to add the new address to the wait queue */
751 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
752 	if (addrw == NULL) {
753 		spin_unlock_bh(&net->sctp.addr_wq_lock);
754 		return;
755 	}
756 	addrw->state = cmd;
757 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
758 
759 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
760 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
761 
762 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
763 		timeo_val = jiffies;
764 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
765 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
766 	}
767 	spin_unlock_bh(&net->sctp.addr_wq_lock);
768 }
769 
770 /* Event handler for inet address addition/deletion events.
771  * The sctp_local_addr_list needs to be protocted by a spin lock since
772  * multiple notifiers (say IPv4 and IPv6) may be running at the same
773  * time and thus corrupt the list.
774  * The reader side is protected with RCU.
775  */
776 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
777 			       void *ptr)
778 {
779 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
780 	struct sctp_sockaddr_entry *addr = NULL;
781 	struct sctp_sockaddr_entry *temp;
782 	struct net *net = dev_net(ifa->ifa_dev->dev);
783 	int found = 0;
784 
785 	switch (ev) {
786 	case NETDEV_UP:
787 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
788 		if (addr) {
789 			addr->a.v4.sin_family = AF_INET;
790 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
791 			addr->valid = 1;
792 			spin_lock_bh(&net->sctp.local_addr_lock);
793 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
794 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
795 			spin_unlock_bh(&net->sctp.local_addr_lock);
796 		}
797 		break;
798 	case NETDEV_DOWN:
799 		spin_lock_bh(&net->sctp.local_addr_lock);
800 		list_for_each_entry_safe(addr, temp,
801 					&net->sctp.local_addr_list, list) {
802 			if (addr->a.sa.sa_family == AF_INET &&
803 					addr->a.v4.sin_addr.s_addr ==
804 					ifa->ifa_local) {
805 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
806 				found = 1;
807 				addr->valid = 0;
808 				list_del_rcu(&addr->list);
809 				break;
810 			}
811 		}
812 		spin_unlock_bh(&net->sctp.local_addr_lock);
813 		if (found)
814 			kfree_rcu(addr, rcu);
815 		break;
816 	}
817 
818 	return NOTIFY_DONE;
819 }
820 
821 /*
822  * Initialize the control inode/socket with a control endpoint data
823  * structure.  This endpoint is reserved exclusively for the OOTB processing.
824  */
825 static int sctp_ctl_sock_init(struct net *net)
826 {
827 	int err;
828 	sa_family_t family = PF_INET;
829 
830 	if (sctp_get_pf_specific(PF_INET6))
831 		family = PF_INET6;
832 
833 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
834 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
835 
836 	/* If IPv6 socket could not be created, try the IPv4 socket */
837 	if (err < 0 && family == PF_INET6)
838 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
839 					   SOCK_SEQPACKET, IPPROTO_SCTP,
840 					   net);
841 
842 	if (err < 0) {
843 		pr_err("Failed to create the SCTP control socket\n");
844 		return err;
845 	}
846 	return 0;
847 }
848 
849 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
850 {
851 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
852 
853 	skb_set_transport_header(skb, sizeof(struct udphdr));
854 	sctp_rcv(skb);
855 	return 0;
856 }
857 
858 int sctp_udp_sock_start(struct net *net)
859 {
860 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
861 	struct udp_port_cfg udp_conf = {0};
862 	struct socket *sock;
863 	int err;
864 
865 	udp_conf.family = AF_INET;
866 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
867 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
868 	err = udp_sock_create(net, &udp_conf, &sock);
869 	if (err) {
870 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
871 		return err;
872 	}
873 
874 	tuncfg.encap_type = 1;
875 	tuncfg.encap_rcv = sctp_udp_rcv;
876 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
877 	setup_udp_tunnel_sock(net, sock, &tuncfg);
878 	net->sctp.udp4_sock = sock->sk;
879 
880 #if IS_ENABLED(CONFIG_IPV6)
881 	memset(&udp_conf, 0, sizeof(udp_conf));
882 
883 	udp_conf.family = AF_INET6;
884 	udp_conf.local_ip6 = in6addr_any;
885 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
886 	udp_conf.use_udp6_rx_checksums = true;
887 	udp_conf.ipv6_v6only = true;
888 	err = udp_sock_create(net, &udp_conf, &sock);
889 	if (err) {
890 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
891 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
892 		net->sctp.udp4_sock = NULL;
893 		return err;
894 	}
895 
896 	tuncfg.encap_type = 1;
897 	tuncfg.encap_rcv = sctp_udp_rcv;
898 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
899 	setup_udp_tunnel_sock(net, sock, &tuncfg);
900 	net->sctp.udp6_sock = sock->sk;
901 #endif
902 
903 	return 0;
904 }
905 
906 void sctp_udp_sock_stop(struct net *net)
907 {
908 	if (net->sctp.udp4_sock) {
909 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
910 		net->sctp.udp4_sock = NULL;
911 	}
912 	if (net->sctp.udp6_sock) {
913 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
914 		net->sctp.udp6_sock = NULL;
915 	}
916 }
917 
918 /* Register address family specific functions. */
919 int sctp_register_af(struct sctp_af *af)
920 {
921 	switch (af->sa_family) {
922 	case AF_INET:
923 		if (sctp_af_v4_specific)
924 			return 0;
925 		sctp_af_v4_specific = af;
926 		break;
927 	case AF_INET6:
928 		if (sctp_af_v6_specific)
929 			return 0;
930 		sctp_af_v6_specific = af;
931 		break;
932 	default:
933 		return 0;
934 	}
935 
936 	INIT_LIST_HEAD(&af->list);
937 	list_add_tail(&af->list, &sctp_address_families);
938 	return 1;
939 }
940 
941 /* Get the table of functions for manipulating a particular address
942  * family.
943  */
944 struct sctp_af *sctp_get_af_specific(sa_family_t family)
945 {
946 	switch (family) {
947 	case AF_INET:
948 		return sctp_af_v4_specific;
949 	case AF_INET6:
950 		return sctp_af_v6_specific;
951 	default:
952 		return NULL;
953 	}
954 }
955 
956 /* Common code to initialize a AF_INET msg_name. */
957 static void sctp_inet_msgname(char *msgname, int *addr_len)
958 {
959 	struct sockaddr_in *sin;
960 
961 	sin = (struct sockaddr_in *)msgname;
962 	*addr_len = sizeof(struct sockaddr_in);
963 	sin->sin_family = AF_INET;
964 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
965 }
966 
967 /* Copy the primary address of the peer primary address as the msg_name. */
968 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
969 				    int *addr_len)
970 {
971 	struct sockaddr_in *sin, *sinfrom;
972 
973 	if (msgname) {
974 		struct sctp_association *asoc;
975 
976 		asoc = event->asoc;
977 		sctp_inet_msgname(msgname, addr_len);
978 		sin = (struct sockaddr_in *)msgname;
979 		sinfrom = &asoc->peer.primary_addr.v4;
980 		sin->sin_port = htons(asoc->peer.port);
981 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
982 	}
983 }
984 
985 /* Initialize and copy out a msgname from an inbound skb. */
986 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
987 {
988 	if (msgname) {
989 		struct sctphdr *sh = sctp_hdr(skb);
990 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
991 
992 		sctp_inet_msgname(msgname, len);
993 		sin->sin_port = sh->source;
994 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
995 	}
996 }
997 
998 /* Do we support this AF? */
999 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1000 {
1001 	/* PF_INET only supports AF_INET addresses. */
1002 	return AF_INET == family;
1003 }
1004 
1005 /* Address matching with wildcards allowed. */
1006 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1007 			      const union sctp_addr *addr2,
1008 			      struct sctp_sock *opt)
1009 {
1010 	/* PF_INET only supports AF_INET addresses. */
1011 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1012 		return 0;
1013 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1014 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1015 		return 1;
1016 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1017 		return 1;
1018 
1019 	return 0;
1020 }
1021 
1022 /* Verify that provided sockaddr looks bindable.  Common verification has
1023  * already been taken care of.
1024  */
1025 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1026 {
1027 	return sctp_v4_available(addr, opt);
1028 }
1029 
1030 /* Verify that sockaddr looks sendable.  Common verification has already
1031  * been taken care of.
1032  */
1033 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1034 {
1035 	return 1;
1036 }
1037 
1038 /* Fill in Supported Address Type information for INIT and INIT-ACK
1039  * chunks.  Returns number of addresses supported.
1040  */
1041 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1042 				     __be16 *types)
1043 {
1044 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1045 	return 1;
1046 }
1047 
1048 /* Wrapper routine that calls the ip transmit routine. */
1049 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1050 {
1051 	struct dst_entry *dst = dst_clone(t->dst);
1052 	struct flowi4 *fl4 = &t->fl.u.ip4;
1053 	struct sock *sk = skb->sk;
1054 	struct inet_sock *inet = inet_sk(sk);
1055 	__u8 dscp = inet->tos;
1056 	__be16 df = 0;
1057 
1058 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1059 		 skb->len, &fl4->saddr, &fl4->daddr);
1060 
1061 	if (t->dscp & SCTP_DSCP_SET_MASK)
1062 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1063 
1064 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1065 							   : IP_PMTUDISC_DONT;
1066 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1067 
1068 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1069 		skb_dst_set(skb, dst);
1070 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1071 	}
1072 
1073 	if (skb_is_gso(skb))
1074 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1075 
1076 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1077 		df = htons(IP_DF);
1078 
1079 	skb->encapsulation = 1;
1080 	skb_reset_inner_mac_header(skb);
1081 	skb_reset_inner_transport_header(skb);
1082 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1083 	udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr,
1084 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1085 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1086 	return 0;
1087 }
1088 
1089 static struct sctp_af sctp_af_inet;
1090 
1091 static struct sctp_pf sctp_pf_inet = {
1092 	.event_msgname = sctp_inet_event_msgname,
1093 	.skb_msgname   = sctp_inet_skb_msgname,
1094 	.af_supported  = sctp_inet_af_supported,
1095 	.cmp_addr      = sctp_inet_cmp_addr,
1096 	.bind_verify   = sctp_inet_bind_verify,
1097 	.send_verify   = sctp_inet_send_verify,
1098 	.supported_addrs = sctp_inet_supported_addrs,
1099 	.create_accept_sk = sctp_v4_create_accept_sk,
1100 	.addr_to_user  = sctp_v4_addr_to_user,
1101 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1102 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1103 	.copy_ip_options = sctp_v4_copy_ip_options,
1104 	.af            = &sctp_af_inet
1105 };
1106 
1107 /* Notifier for inetaddr addition/deletion events.  */
1108 static struct notifier_block sctp_inetaddr_notifier = {
1109 	.notifier_call = sctp_inetaddr_event,
1110 };
1111 
1112 /* Socket operations.  */
1113 static const struct proto_ops inet_seqpacket_ops = {
1114 	.family		   = PF_INET,
1115 	.owner		   = THIS_MODULE,
1116 	.release	   = inet_release,	/* Needs to be wrapped... */
1117 	.bind		   = inet_bind,
1118 	.connect	   = sctp_inet_connect,
1119 	.socketpair	   = sock_no_socketpair,
1120 	.accept		   = inet_accept,
1121 	.getname	   = inet_getname,	/* Semantics are different.  */
1122 	.poll		   = sctp_poll,
1123 	.ioctl		   = inet_ioctl,
1124 	.gettstamp	   = sock_gettstamp,
1125 	.listen		   = sctp_inet_listen,
1126 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1127 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1128 	.getsockopt	   = sock_common_getsockopt,
1129 	.sendmsg	   = inet_sendmsg,
1130 	.recvmsg	   = inet_recvmsg,
1131 	.mmap		   = sock_no_mmap,
1132 	.sendpage	   = sock_no_sendpage,
1133 };
1134 
1135 /* Registration with AF_INET family.  */
1136 static struct inet_protosw sctp_seqpacket_protosw = {
1137 	.type       = SOCK_SEQPACKET,
1138 	.protocol   = IPPROTO_SCTP,
1139 	.prot       = &sctp_prot,
1140 	.ops        = &inet_seqpacket_ops,
1141 	.flags      = SCTP_PROTOSW_FLAG
1142 };
1143 static struct inet_protosw sctp_stream_protosw = {
1144 	.type       = SOCK_STREAM,
1145 	.protocol   = IPPROTO_SCTP,
1146 	.prot       = &sctp_prot,
1147 	.ops        = &inet_seqpacket_ops,
1148 	.flags      = SCTP_PROTOSW_FLAG
1149 };
1150 
1151 static int sctp4_rcv(struct sk_buff *skb)
1152 {
1153 	SCTP_INPUT_CB(skb)->encap_port = 0;
1154 	return sctp_rcv(skb);
1155 }
1156 
1157 /* Register with IP layer.  */
1158 static const struct net_protocol sctp_protocol = {
1159 	.handler     = sctp4_rcv,
1160 	.err_handler = sctp_v4_err,
1161 	.no_policy   = 1,
1162 	.icmp_strict_tag_validation = 1,
1163 };
1164 
1165 /* IPv4 address related functions.  */
1166 static struct sctp_af sctp_af_inet = {
1167 	.sa_family	   = AF_INET,
1168 	.sctp_xmit	   = sctp_v4_xmit,
1169 	.setsockopt	   = ip_setsockopt,
1170 	.getsockopt	   = ip_getsockopt,
1171 	.get_dst	   = sctp_v4_get_dst,
1172 	.get_saddr	   = sctp_v4_get_saddr,
1173 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1174 	.from_skb	   = sctp_v4_from_skb,
1175 	.from_sk	   = sctp_v4_from_sk,
1176 	.from_addr_param   = sctp_v4_from_addr_param,
1177 	.to_addr_param	   = sctp_v4_to_addr_param,
1178 	.cmp_addr	   = sctp_v4_cmp_addr,
1179 	.addr_valid	   = sctp_v4_addr_valid,
1180 	.inaddr_any	   = sctp_v4_inaddr_any,
1181 	.is_any		   = sctp_v4_is_any,
1182 	.available	   = sctp_v4_available,
1183 	.scope		   = sctp_v4_scope,
1184 	.skb_iif	   = sctp_v4_skb_iif,
1185 	.is_ce		   = sctp_v4_is_ce,
1186 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1187 	.ecn_capable	   = sctp_v4_ecn_capable,
1188 	.net_header_len	   = sizeof(struct iphdr),
1189 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1190 	.ip_options_len	   = sctp_v4_ip_options_len,
1191 };
1192 
1193 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1194 {
1195 	switch (family) {
1196 	case PF_INET:
1197 		return sctp_pf_inet_specific;
1198 	case PF_INET6:
1199 		return sctp_pf_inet6_specific;
1200 	default:
1201 		return NULL;
1202 	}
1203 }
1204 
1205 /* Register the PF specific function table.  */
1206 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1207 {
1208 	switch (family) {
1209 	case PF_INET:
1210 		if (sctp_pf_inet_specific)
1211 			return 0;
1212 		sctp_pf_inet_specific = pf;
1213 		break;
1214 	case PF_INET6:
1215 		if (sctp_pf_inet6_specific)
1216 			return 0;
1217 		sctp_pf_inet6_specific = pf;
1218 		break;
1219 	default:
1220 		return 0;
1221 	}
1222 	return 1;
1223 }
1224 
1225 static inline int init_sctp_mibs(struct net *net)
1226 {
1227 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1228 	if (!net->sctp.sctp_statistics)
1229 		return -ENOMEM;
1230 	return 0;
1231 }
1232 
1233 static inline void cleanup_sctp_mibs(struct net *net)
1234 {
1235 	free_percpu(net->sctp.sctp_statistics);
1236 }
1237 
1238 static void sctp_v4_pf_init(void)
1239 {
1240 	/* Initialize the SCTP specific PF functions. */
1241 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1242 	sctp_register_af(&sctp_af_inet);
1243 }
1244 
1245 static void sctp_v4_pf_exit(void)
1246 {
1247 	list_del(&sctp_af_inet.list);
1248 }
1249 
1250 static int sctp_v4_protosw_init(void)
1251 {
1252 	int rc;
1253 
1254 	rc = proto_register(&sctp_prot, 1);
1255 	if (rc)
1256 		return rc;
1257 
1258 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1259 	inet_register_protosw(&sctp_seqpacket_protosw);
1260 	inet_register_protosw(&sctp_stream_protosw);
1261 
1262 	return 0;
1263 }
1264 
1265 static void sctp_v4_protosw_exit(void)
1266 {
1267 	inet_unregister_protosw(&sctp_stream_protosw);
1268 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1269 	proto_unregister(&sctp_prot);
1270 }
1271 
1272 static int sctp_v4_add_protocol(void)
1273 {
1274 	/* Register notifier for inet address additions/deletions. */
1275 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1276 
1277 	/* Register SCTP with inet layer.  */
1278 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1279 		return -EAGAIN;
1280 
1281 	return 0;
1282 }
1283 
1284 static void sctp_v4_del_protocol(void)
1285 {
1286 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1287 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1288 }
1289 
1290 static int __net_init sctp_defaults_init(struct net *net)
1291 {
1292 	int status;
1293 
1294 	/*
1295 	 * 14. Suggested SCTP Protocol Parameter Values
1296 	 */
1297 	/* The following protocol parameters are RECOMMENDED:  */
1298 	/* RTO.Initial              - 3  seconds */
1299 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1300 	/* RTO.Min                  - 1  second */
1301 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1302 	/* RTO.Max                 -  60 seconds */
1303 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1304 	/* RTO.Alpha                - 1/8 */
1305 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1306 	/* RTO.Beta                 - 1/4 */
1307 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1308 
1309 	/* Valid.Cookie.Life        - 60  seconds */
1310 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1311 
1312 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1313 	net->sctp.cookie_preserve_enable 	= 1;
1314 
1315 	/* Default sctp sockets to use md5 as their hmac alg */
1316 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1317 	net->sctp.sctp_hmac_alg			= "md5";
1318 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1319 	net->sctp.sctp_hmac_alg			= "sha1";
1320 #else
1321 	net->sctp.sctp_hmac_alg			= NULL;
1322 #endif
1323 
1324 	/* Max.Burst		    - 4 */
1325 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1326 
1327 	/* Disable of Primary Path Switchover by default */
1328 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1329 
1330 	/* Enable pf state by default */
1331 	net->sctp.pf_enable = 1;
1332 
1333 	/* Ignore pf exposure feature by default */
1334 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1335 
1336 	/* Association.Max.Retrans  - 10 attempts
1337 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1338 	 * Max.Init.Retransmits     - 8  attempts
1339 	 */
1340 	net->sctp.max_retrans_association	= 10;
1341 	net->sctp.max_retrans_path		= 5;
1342 	net->sctp.max_retrans_init		= 8;
1343 
1344 	/* Sendbuffer growth	    - do per-socket accounting */
1345 	net->sctp.sndbuf_policy			= 0;
1346 
1347 	/* Rcvbuffer growth	    - do per-socket accounting */
1348 	net->sctp.rcvbuf_policy			= 0;
1349 
1350 	/* HB.interval              - 30 seconds */
1351 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1352 
1353 	/* delayed SACK timeout */
1354 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1355 
1356 	/* Disable ADDIP by default. */
1357 	net->sctp.addip_enable = 0;
1358 	net->sctp.addip_noauth = 0;
1359 	net->sctp.default_auto_asconf = 0;
1360 
1361 	/* Enable PR-SCTP by default. */
1362 	net->sctp.prsctp_enable = 1;
1363 
1364 	/* Disable RECONF by default. */
1365 	net->sctp.reconf_enable = 0;
1366 
1367 	/* Disable AUTH by default. */
1368 	net->sctp.auth_enable = 0;
1369 
1370 	/* Enable ECN by default. */
1371 	net->sctp.ecn_enable = 1;
1372 
1373 	/* Set UDP tunneling listening port to 0 by default */
1374 	net->sctp.udp_port = 0;
1375 
1376 	/* Set remote encap port to 0 by default */
1377 	net->sctp.encap_port = 0;
1378 
1379 	/* Set SCOPE policy to enabled */
1380 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1381 
1382 	/* Set the default rwnd update threshold */
1383 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1384 
1385 	/* Initialize maximum autoclose timeout. */
1386 	net->sctp.max_autoclose		= INT_MAX / HZ;
1387 
1388 	status = sctp_sysctl_net_register(net);
1389 	if (status)
1390 		goto err_sysctl_register;
1391 
1392 	/* Allocate and initialise sctp mibs.  */
1393 	status = init_sctp_mibs(net);
1394 	if (status)
1395 		goto err_init_mibs;
1396 
1397 #ifdef CONFIG_PROC_FS
1398 	/* Initialize proc fs directory.  */
1399 	status = sctp_proc_init(net);
1400 	if (status)
1401 		goto err_init_proc;
1402 #endif
1403 
1404 	sctp_dbg_objcnt_init(net);
1405 
1406 	/* Initialize the local address list. */
1407 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1408 	spin_lock_init(&net->sctp.local_addr_lock);
1409 	sctp_get_local_addr_list(net);
1410 
1411 	/* Initialize the address event list */
1412 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1413 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1414 	spin_lock_init(&net->sctp.addr_wq_lock);
1415 	net->sctp.addr_wq_timer.expires = 0;
1416 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1417 
1418 	return 0;
1419 
1420 #ifdef CONFIG_PROC_FS
1421 err_init_proc:
1422 	cleanup_sctp_mibs(net);
1423 #endif
1424 err_init_mibs:
1425 	sctp_sysctl_net_unregister(net);
1426 err_sysctl_register:
1427 	return status;
1428 }
1429 
1430 static void __net_exit sctp_defaults_exit(struct net *net)
1431 {
1432 	/* Free the local address list */
1433 	sctp_free_addr_wq(net);
1434 	sctp_free_local_addr_list(net);
1435 
1436 #ifdef CONFIG_PROC_FS
1437 	remove_proc_subtree("sctp", net->proc_net);
1438 	net->sctp.proc_net_sctp = NULL;
1439 #endif
1440 	cleanup_sctp_mibs(net);
1441 	sctp_sysctl_net_unregister(net);
1442 }
1443 
1444 static struct pernet_operations sctp_defaults_ops = {
1445 	.init = sctp_defaults_init,
1446 	.exit = sctp_defaults_exit,
1447 };
1448 
1449 static int __net_init sctp_ctrlsock_init(struct net *net)
1450 {
1451 	int status;
1452 
1453 	/* Initialize the control inode/socket for handling OOTB packets.  */
1454 	status = sctp_ctl_sock_init(net);
1455 	if (status)
1456 		pr_err("Failed to initialize the SCTP control sock\n");
1457 
1458 	return status;
1459 }
1460 
1461 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1462 {
1463 	/* Free the control endpoint.  */
1464 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1465 }
1466 
1467 static struct pernet_operations sctp_ctrlsock_ops = {
1468 	.init = sctp_ctrlsock_init,
1469 	.exit = sctp_ctrlsock_exit,
1470 };
1471 
1472 /* Initialize the universe into something sensible.  */
1473 static __init int sctp_init(void)
1474 {
1475 	unsigned long nr_pages = totalram_pages();
1476 	unsigned long limit;
1477 	unsigned long goal;
1478 	int max_entry_order;
1479 	int num_entries;
1480 	int max_share;
1481 	int status;
1482 	int order;
1483 	int i;
1484 
1485 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1486 
1487 	/* Allocate bind_bucket and chunk caches. */
1488 	status = -ENOBUFS;
1489 	sctp_bucket_cachep = kmem_cache_create("sctp_bind_bucket",
1490 					       sizeof(struct sctp_bind_bucket),
1491 					       0, SLAB_HWCACHE_ALIGN,
1492 					       NULL);
1493 	if (!sctp_bucket_cachep)
1494 		goto out;
1495 
1496 	sctp_chunk_cachep = kmem_cache_create("sctp_chunk",
1497 					       sizeof(struct sctp_chunk),
1498 					       0, SLAB_HWCACHE_ALIGN,
1499 					       NULL);
1500 	if (!sctp_chunk_cachep)
1501 		goto err_chunk_cachep;
1502 
1503 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1504 	if (status)
1505 		goto err_percpu_counter_init;
1506 
1507 	/* Implementation specific variables. */
1508 
1509 	/* Initialize default stream count setup information. */
1510 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1511 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1512 
1513 	/* Initialize handle used for association ids. */
1514 	idr_init(&sctp_assocs_id);
1515 
1516 	limit = nr_free_buffer_pages() / 8;
1517 	limit = max(limit, 128UL);
1518 	sysctl_sctp_mem[0] = limit / 4 * 3;
1519 	sysctl_sctp_mem[1] = limit;
1520 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1521 
1522 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1523 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1524 	max_share = min(4UL*1024*1024, limit);
1525 
1526 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1527 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1528 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1529 
1530 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1531 	sysctl_sctp_wmem[1] = 16*1024;
1532 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1533 
1534 	/* Size and allocate the association hash table.
1535 	 * The methodology is similar to that of the tcp hash tables.
1536 	 * Though not identical.  Start by getting a goal size
1537 	 */
1538 	if (nr_pages >= (128 * 1024))
1539 		goal = nr_pages >> (22 - PAGE_SHIFT);
1540 	else
1541 		goal = nr_pages >> (24 - PAGE_SHIFT);
1542 
1543 	/* Then compute the page order for said goal */
1544 	order = get_order(goal);
1545 
1546 	/* Now compute the required page order for the maximum sized table we
1547 	 * want to create
1548 	 */
1549 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1550 				    sizeof(struct sctp_bind_hashbucket));
1551 
1552 	/* Limit the page order by that maximum hash table size */
1553 	order = min(order, max_entry_order);
1554 
1555 	/* Allocate and initialize the endpoint hash table.  */
1556 	sctp_ep_hashsize = 64;
1557 	sctp_ep_hashtable =
1558 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1559 	if (!sctp_ep_hashtable) {
1560 		pr_err("Failed endpoint_hash alloc\n");
1561 		status = -ENOMEM;
1562 		goto err_ehash_alloc;
1563 	}
1564 	for (i = 0; i < sctp_ep_hashsize; i++) {
1565 		rwlock_init(&sctp_ep_hashtable[i].lock);
1566 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1567 	}
1568 
1569 	/* Allocate and initialize the SCTP port hash table.
1570 	 * Note that order is initalized to start at the max sized
1571 	 * table we want to support.  If we can't get that many pages
1572 	 * reduce the order and try again
1573 	 */
1574 	do {
1575 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1576 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1577 	} while (!sctp_port_hashtable && --order > 0);
1578 
1579 	if (!sctp_port_hashtable) {
1580 		pr_err("Failed bind hash alloc\n");
1581 		status = -ENOMEM;
1582 		goto err_bhash_alloc;
1583 	}
1584 
1585 	/* Now compute the number of entries that will fit in the
1586 	 * port hash space we allocated
1587 	 */
1588 	num_entries = (1UL << order) * PAGE_SIZE /
1589 		      sizeof(struct sctp_bind_hashbucket);
1590 
1591 	/* And finish by rounding it down to the nearest power of two.
1592 	 * This wastes some memory of course, but it's needed because
1593 	 * the hash function operates based on the assumption that
1594 	 * the number of entries is a power of two.
1595 	 */
1596 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1597 
1598 	for (i = 0; i < sctp_port_hashsize; i++) {
1599 		spin_lock_init(&sctp_port_hashtable[i].lock);
1600 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1601 	}
1602 
1603 	status = sctp_transport_hashtable_init();
1604 	if (status)
1605 		goto err_thash_alloc;
1606 
1607 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1608 		num_entries);
1609 
1610 	sctp_sysctl_register();
1611 
1612 	INIT_LIST_HEAD(&sctp_address_families);
1613 	sctp_v4_pf_init();
1614 	sctp_v6_pf_init();
1615 	sctp_sched_ops_init();
1616 
1617 	status = register_pernet_subsys(&sctp_defaults_ops);
1618 	if (status)
1619 		goto err_register_defaults;
1620 
1621 	status = sctp_v4_protosw_init();
1622 	if (status)
1623 		goto err_protosw_init;
1624 
1625 	status = sctp_v6_protosw_init();
1626 	if (status)
1627 		goto err_v6_protosw_init;
1628 
1629 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1630 	if (status)
1631 		goto err_register_ctrlsock;
1632 
1633 	status = sctp_v4_add_protocol();
1634 	if (status)
1635 		goto err_add_protocol;
1636 
1637 	/* Register SCTP with inet6 layer.  */
1638 	status = sctp_v6_add_protocol();
1639 	if (status)
1640 		goto err_v6_add_protocol;
1641 
1642 	if (sctp_offload_init() < 0)
1643 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1644 
1645 out:
1646 	return status;
1647 err_v6_add_protocol:
1648 	sctp_v4_del_protocol();
1649 err_add_protocol:
1650 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1651 err_register_ctrlsock:
1652 	sctp_v6_protosw_exit();
1653 err_v6_protosw_init:
1654 	sctp_v4_protosw_exit();
1655 err_protosw_init:
1656 	unregister_pernet_subsys(&sctp_defaults_ops);
1657 err_register_defaults:
1658 	sctp_v4_pf_exit();
1659 	sctp_v6_pf_exit();
1660 	sctp_sysctl_unregister();
1661 	free_pages((unsigned long)sctp_port_hashtable,
1662 		   get_order(sctp_port_hashsize *
1663 			     sizeof(struct sctp_bind_hashbucket)));
1664 err_bhash_alloc:
1665 	sctp_transport_hashtable_destroy();
1666 err_thash_alloc:
1667 	kfree(sctp_ep_hashtable);
1668 err_ehash_alloc:
1669 	percpu_counter_destroy(&sctp_sockets_allocated);
1670 err_percpu_counter_init:
1671 	kmem_cache_destroy(sctp_chunk_cachep);
1672 err_chunk_cachep:
1673 	kmem_cache_destroy(sctp_bucket_cachep);
1674 	goto out;
1675 }
1676 
1677 /* Exit handler for the SCTP protocol.  */
1678 static __exit void sctp_exit(void)
1679 {
1680 	/* BUG.  This should probably do something useful like clean
1681 	 * up all the remaining associations and all that memory.
1682 	 */
1683 
1684 	/* Unregister with inet6/inet layers. */
1685 	sctp_v6_del_protocol();
1686 	sctp_v4_del_protocol();
1687 
1688 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1689 
1690 	/* Free protosw registrations */
1691 	sctp_v6_protosw_exit();
1692 	sctp_v4_protosw_exit();
1693 
1694 	unregister_pernet_subsys(&sctp_defaults_ops);
1695 
1696 	/* Unregister with socket layer. */
1697 	sctp_v6_pf_exit();
1698 	sctp_v4_pf_exit();
1699 
1700 	sctp_sysctl_unregister();
1701 
1702 	free_pages((unsigned long)sctp_port_hashtable,
1703 		   get_order(sctp_port_hashsize *
1704 			     sizeof(struct sctp_bind_hashbucket)));
1705 	kfree(sctp_ep_hashtable);
1706 	sctp_transport_hashtable_destroy();
1707 
1708 	percpu_counter_destroy(&sctp_sockets_allocated);
1709 
1710 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1711 
1712 	kmem_cache_destroy(sctp_chunk_cachep);
1713 	kmem_cache_destroy(sctp_bucket_cachep);
1714 }
1715 
1716 module_init(sctp_init);
1717 module_exit(sctp_exit);
1718 
1719 /*
1720  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1721  */
1722 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1723 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1724 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1725 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1726 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1727 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1728 MODULE_LICENSE("GPL");
1729