xref: /linux/net/sctp/protocol.c (revision 9052e9c95d908d6c3d7570aadc8898e1d871c8bb)
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/swap.h>
37 #include <linux/slab.h>
38 #include <net/net_namespace.h>
39 #include <net/protocol.h>
40 #include <net/ip.h>
41 #include <net/ipv6.h>
42 #include <net/route.h>
43 #include <net/sctp/sctp.h>
44 #include <net/addrconf.h>
45 #include <net/inet_common.h>
46 #include <net/inet_ecn.h>
47 #include <net/udp_tunnel.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 net *net = sock_net(&sp->inet.sk);
356 	int ret = inet_addr_type(net, addr->v4.sin_addr.s_addr);
357 
358 
359 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
360 	   ret != RTN_LOCAL &&
361 	   !sp->inet.freebind &&
362 	   !net->ipv4.sysctl_ip_nonlocal_bind)
363 		return 0;
364 
365 	if (ipv6_only_sock(sctp_opt2sk(sp)))
366 		return 0;
367 
368 	return 1;
369 }
370 
371 /* Checking the loopback, private and other address scopes as defined in
372  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
373  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
374  *
375  * Level 0 - unusable SCTP addresses
376  * Level 1 - loopback address
377  * Level 2 - link-local addresses
378  * Level 3 - private addresses.
379  * Level 4 - global addresses
380  * For INIT and INIT-ACK address list, let L be the level of
381  * requested destination address, sender and receiver
382  * SHOULD include all of its addresses with level greater
383  * than or equal to L.
384  *
385  * IPv4 scoping can be controlled through sysctl option
386  * net.sctp.addr_scope_policy
387  */
388 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
389 {
390 	enum sctp_scope retval;
391 
392 	/* Check for unusable SCTP addresses. */
393 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
394 		retval =  SCTP_SCOPE_UNUSABLE;
395 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
396 		retval = SCTP_SCOPE_LOOPBACK;
397 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
398 		retval = SCTP_SCOPE_LINK;
399 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
400 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
401 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
402 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
403 		retval = SCTP_SCOPE_PRIVATE;
404 	} else {
405 		retval = SCTP_SCOPE_GLOBAL;
406 	}
407 
408 	return retval;
409 }
410 
411 /* Returns a valid dst cache entry for the given source and destination ip
412  * addresses. If an association is passed, trys to get a dst entry with a
413  * source address that matches an address in the bind address list.
414  */
415 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
416 				struct flowi *fl, struct sock *sk)
417 {
418 	struct sctp_association *asoc = t->asoc;
419 	struct rtable *rt;
420 	struct flowi _fl;
421 	struct flowi4 *fl4 = &_fl.u.ip4;
422 	struct sctp_bind_addr *bp;
423 	struct sctp_sockaddr_entry *laddr;
424 	struct dst_entry *dst = NULL;
425 	union sctp_addr *daddr = &t->ipaddr;
426 	union sctp_addr dst_saddr;
427 	__u8 tos = inet_sk(sk)->tos;
428 
429 	if (t->dscp & SCTP_DSCP_SET_MASK)
430 		tos = t->dscp & SCTP_DSCP_VAL_MASK;
431 	memset(&_fl, 0x0, sizeof(_fl));
432 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
433 	fl4->fl4_dport = daddr->v4.sin_port;
434 	fl4->flowi4_proto = IPPROTO_SCTP;
435 	if (asoc) {
436 		fl4->flowi4_tos = RT_CONN_FLAGS_TOS(asoc->base.sk, tos);
437 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
438 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
439 	}
440 	if (saddr) {
441 		fl4->saddr = saddr->v4.sin_addr.s_addr;
442 		if (!fl4->fl4_sport)
443 			fl4->fl4_sport = saddr->v4.sin_port;
444 	}
445 
446 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
447 		 &fl4->saddr);
448 
449 	rt = ip_route_output_key(sock_net(sk), fl4);
450 	if (!IS_ERR(rt)) {
451 		dst = &rt->dst;
452 		t->dst = dst;
453 		memcpy(fl, &_fl, sizeof(_fl));
454 	}
455 
456 	/* If there is no association or if a source address is passed, no
457 	 * more validation is required.
458 	 */
459 	if (!asoc || saddr)
460 		goto out;
461 
462 	bp = &asoc->base.bind_addr;
463 
464 	if (dst) {
465 		/* Walk through the bind address list and look for a bind
466 		 * address that matches the source address of the returned dst.
467 		 */
468 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
469 		rcu_read_lock();
470 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
471 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
472 			    (laddr->state != SCTP_ADDR_SRC &&
473 			    !asoc->src_out_of_asoc_ok))
474 				continue;
475 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
476 				goto out_unlock;
477 		}
478 		rcu_read_unlock();
479 
480 		/* None of the bound addresses match the source address of the
481 		 * dst. So release it.
482 		 */
483 		dst_release(dst);
484 		dst = NULL;
485 	}
486 
487 	/* Walk through the bind address list and try to get a dst that
488 	 * matches a bind address as the source address.
489 	 */
490 	rcu_read_lock();
491 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
492 		struct net_device *odev;
493 
494 		if (!laddr->valid)
495 			continue;
496 		if (laddr->state != SCTP_ADDR_SRC ||
497 		    AF_INET != laddr->a.sa.sa_family)
498 			continue;
499 
500 		fl4->fl4_sport = laddr->a.v4.sin_port;
501 		flowi4_update_output(fl4,
502 				     asoc->base.sk->sk_bound_dev_if,
503 				     RT_CONN_FLAGS_TOS(asoc->base.sk, tos),
504 				     daddr->v4.sin_addr.s_addr,
505 				     laddr->a.v4.sin_addr.s_addr);
506 
507 		rt = ip_route_output_key(sock_net(sk), fl4);
508 		if (IS_ERR(rt))
509 			continue;
510 
511 		/* Ensure the src address belongs to the output
512 		 * interface.
513 		 */
514 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
515 				     false);
516 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
517 			if (!dst) {
518 				dst = &rt->dst;
519 				t->dst = dst;
520 				memcpy(fl, &_fl, sizeof(_fl));
521 			} else {
522 				dst_release(&rt->dst);
523 			}
524 			continue;
525 		}
526 
527 		dst_release(dst);
528 		dst = &rt->dst;
529 		t->dst = dst;
530 		memcpy(fl, &_fl, sizeof(_fl));
531 		break;
532 	}
533 
534 out_unlock:
535 	rcu_read_unlock();
536 out:
537 	if (dst) {
538 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
539 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
540 	} else {
541 		t->dst = NULL;
542 		pr_debug("no route\n");
543 	}
544 }
545 
546 /* For v4, the source address is cached in the route entry(dst). So no need
547  * to cache it separately and hence this is an empty routine.
548  */
549 static void sctp_v4_get_saddr(struct sctp_sock *sk,
550 			      struct sctp_transport *t,
551 			      struct flowi *fl)
552 {
553 	union sctp_addr *saddr = &t->saddr;
554 	struct rtable *rt = (struct rtable *)t->dst;
555 
556 	if (rt) {
557 		saddr->v4.sin_family = AF_INET;
558 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
559 	}
560 }
561 
562 /* What interface did this skb arrive on? */
563 static int sctp_v4_skb_iif(const struct sk_buff *skb)
564 {
565 	return inet_iif(skb);
566 }
567 
568 /* Was this packet marked by Explicit Congestion Notification? */
569 static int sctp_v4_is_ce(const struct sk_buff *skb)
570 {
571 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
572 }
573 
574 /* Create and initialize a new sk for the socket returned by accept(). */
575 static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
576 					     struct sctp_association *asoc,
577 					     bool kern)
578 {
579 	struct sock *newsk = sk_alloc(sock_net(sk), PF_INET, GFP_KERNEL,
580 			sk->sk_prot, kern);
581 	struct inet_sock *newinet;
582 
583 	if (!newsk)
584 		goto out;
585 
586 	sock_init_data(NULL, newsk);
587 
588 	sctp_copy_sock(newsk, sk, asoc);
589 	sock_reset_flag(newsk, SOCK_ZAPPED);
590 
591 	sctp_v4_copy_ip_options(sk, newsk);
592 
593 	newinet = inet_sk(newsk);
594 
595 	newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
596 
597 	sk_refcnt_debug_inc(newsk);
598 
599 	if (newsk->sk_prot->init(newsk)) {
600 		sk_common_release(newsk);
601 		newsk = NULL;
602 	}
603 
604 out:
605 	return newsk;
606 }
607 
608 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
609 {
610 	/* No address mapping for V4 sockets */
611 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
612 	return sizeof(struct sockaddr_in);
613 }
614 
615 /* Dump the v4 addr to the seq file. */
616 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
617 {
618 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
619 }
620 
621 static void sctp_v4_ecn_capable(struct sock *sk)
622 {
623 	INET_ECN_xmit(sk);
624 }
625 
626 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
627 {
628 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
629 	struct sctp_sockaddr_entry *addrw, *temp;
630 	struct sctp_sock *sp;
631 
632 	spin_lock_bh(&net->sctp.addr_wq_lock);
633 
634 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
635 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
636 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
637 			 addrw->state, addrw);
638 
639 #if IS_ENABLED(CONFIG_IPV6)
640 		/* Now we send an ASCONF for each association */
641 		/* Note. we currently don't handle link local IPv6 addressees */
642 		if (addrw->a.sa.sa_family == AF_INET6) {
643 			struct in6_addr *in6;
644 
645 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
646 			    IPV6_ADDR_LINKLOCAL)
647 				goto free_next;
648 
649 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
650 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
651 			    addrw->state == SCTP_ADDR_NEW) {
652 				unsigned long timeo_val;
653 
654 				pr_debug("%s: this is on DAD, trying %d sec "
655 					 "later\n", __func__,
656 					 SCTP_ADDRESS_TICK_DELAY);
657 
658 				timeo_val = jiffies;
659 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
660 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
661 				break;
662 			}
663 		}
664 #endif
665 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
666 			struct sock *sk;
667 
668 			sk = sctp_opt2sk(sp);
669 			/* ignore bound-specific endpoints */
670 			if (!sctp_is_ep_boundall(sk))
671 				continue;
672 			bh_lock_sock(sk);
673 			if (sctp_asconf_mgmt(sp, addrw) < 0)
674 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
675 			bh_unlock_sock(sk);
676 		}
677 #if IS_ENABLED(CONFIG_IPV6)
678 free_next:
679 #endif
680 		list_del(&addrw->list);
681 		kfree(addrw);
682 	}
683 	spin_unlock_bh(&net->sctp.addr_wq_lock);
684 }
685 
686 static void sctp_free_addr_wq(struct net *net)
687 {
688 	struct sctp_sockaddr_entry *addrw;
689 	struct sctp_sockaddr_entry *temp;
690 
691 	spin_lock_bh(&net->sctp.addr_wq_lock);
692 	del_timer(&net->sctp.addr_wq_timer);
693 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
694 		list_del(&addrw->list);
695 		kfree(addrw);
696 	}
697 	spin_unlock_bh(&net->sctp.addr_wq_lock);
698 }
699 
700 /* lookup the entry for the same address in the addr_waitq
701  * sctp_addr_wq MUST be locked
702  */
703 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
704 					struct sctp_sockaddr_entry *addr)
705 {
706 	struct sctp_sockaddr_entry *addrw;
707 
708 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
709 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
710 			continue;
711 		if (addrw->a.sa.sa_family == AF_INET) {
712 			if (addrw->a.v4.sin_addr.s_addr ==
713 			    addr->a.v4.sin_addr.s_addr)
714 				return addrw;
715 		} else if (addrw->a.sa.sa_family == AF_INET6) {
716 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
717 			    &addr->a.v6.sin6_addr))
718 				return addrw;
719 		}
720 	}
721 	return NULL;
722 }
723 
724 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
725 {
726 	struct sctp_sockaddr_entry *addrw;
727 	unsigned long timeo_val;
728 
729 	/* first, we check if an opposite message already exist in the queue.
730 	 * If we found such message, it is removed.
731 	 * This operation is a bit stupid, but the DHCP client attaches the
732 	 * new address after a couple of addition and deletion of that address
733 	 */
734 
735 	spin_lock_bh(&net->sctp.addr_wq_lock);
736 	/* Offsets existing events in addr_wq */
737 	addrw = sctp_addr_wq_lookup(net, addr);
738 	if (addrw) {
739 		if (addrw->state != cmd) {
740 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
741 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
742 				 &net->sctp.addr_waitq);
743 
744 			list_del(&addrw->list);
745 			kfree(addrw);
746 		}
747 		spin_unlock_bh(&net->sctp.addr_wq_lock);
748 		return;
749 	}
750 
751 	/* OK, we have to add the new address to the wait queue */
752 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
753 	if (addrw == NULL) {
754 		spin_unlock_bh(&net->sctp.addr_wq_lock);
755 		return;
756 	}
757 	addrw->state = cmd;
758 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
759 
760 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
761 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
762 
763 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
764 		timeo_val = jiffies;
765 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
766 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
767 	}
768 	spin_unlock_bh(&net->sctp.addr_wq_lock);
769 }
770 
771 /* Event handler for inet address addition/deletion events.
772  * The sctp_local_addr_list needs to be protocted by a spin lock since
773  * multiple notifiers (say IPv4 and IPv6) may be running at the same
774  * time and thus corrupt the list.
775  * The reader side is protected with RCU.
776  */
777 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
778 			       void *ptr)
779 {
780 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
781 	struct sctp_sockaddr_entry *addr = NULL;
782 	struct sctp_sockaddr_entry *temp;
783 	struct net *net = dev_net(ifa->ifa_dev->dev);
784 	int found = 0;
785 
786 	switch (ev) {
787 	case NETDEV_UP:
788 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
789 		if (addr) {
790 			addr->a.v4.sin_family = AF_INET;
791 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
792 			addr->valid = 1;
793 			spin_lock_bh(&net->sctp.local_addr_lock);
794 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
795 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
796 			spin_unlock_bh(&net->sctp.local_addr_lock);
797 		}
798 		break;
799 	case NETDEV_DOWN:
800 		spin_lock_bh(&net->sctp.local_addr_lock);
801 		list_for_each_entry_safe(addr, temp,
802 					&net->sctp.local_addr_list, list) {
803 			if (addr->a.sa.sa_family == AF_INET &&
804 					addr->a.v4.sin_addr.s_addr ==
805 					ifa->ifa_local) {
806 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
807 				found = 1;
808 				addr->valid = 0;
809 				list_del_rcu(&addr->list);
810 				break;
811 			}
812 		}
813 		spin_unlock_bh(&net->sctp.local_addr_lock);
814 		if (found)
815 			kfree_rcu(addr, rcu);
816 		break;
817 	}
818 
819 	return NOTIFY_DONE;
820 }
821 
822 /*
823  * Initialize the control inode/socket with a control endpoint data
824  * structure.  This endpoint is reserved exclusively for the OOTB processing.
825  */
826 static int sctp_ctl_sock_init(struct net *net)
827 {
828 	int err;
829 	sa_family_t family = PF_INET;
830 
831 	if (sctp_get_pf_specific(PF_INET6))
832 		family = PF_INET6;
833 
834 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
835 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
836 
837 	/* If IPv6 socket could not be created, try the IPv4 socket */
838 	if (err < 0 && family == PF_INET6)
839 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
840 					   SOCK_SEQPACKET, IPPROTO_SCTP,
841 					   net);
842 
843 	if (err < 0) {
844 		pr_err("Failed to create the SCTP control socket\n");
845 		return err;
846 	}
847 	return 0;
848 }
849 
850 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
851 {
852 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
853 
854 	skb_set_transport_header(skb, sizeof(struct udphdr));
855 	sctp_rcv(skb);
856 	return 0;
857 }
858 
859 int sctp_udp_sock_start(struct net *net)
860 {
861 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
862 	struct udp_port_cfg udp_conf = {0};
863 	struct socket *sock;
864 	int err;
865 
866 	udp_conf.family = AF_INET;
867 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
868 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
869 	err = udp_sock_create(net, &udp_conf, &sock);
870 	if (err) {
871 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
872 		return err;
873 	}
874 
875 	tuncfg.encap_type = 1;
876 	tuncfg.encap_rcv = sctp_udp_rcv;
877 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
878 	setup_udp_tunnel_sock(net, sock, &tuncfg);
879 	net->sctp.udp4_sock = sock->sk;
880 
881 #if IS_ENABLED(CONFIG_IPV6)
882 	memset(&udp_conf, 0, sizeof(udp_conf));
883 
884 	udp_conf.family = AF_INET6;
885 	udp_conf.local_ip6 = in6addr_any;
886 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
887 	udp_conf.use_udp6_rx_checksums = true;
888 	udp_conf.ipv6_v6only = true;
889 	err = udp_sock_create(net, &udp_conf, &sock);
890 	if (err) {
891 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
892 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
893 		net->sctp.udp4_sock = NULL;
894 		return err;
895 	}
896 
897 	tuncfg.encap_type = 1;
898 	tuncfg.encap_rcv = sctp_udp_rcv;
899 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
900 	setup_udp_tunnel_sock(net, sock, &tuncfg);
901 	net->sctp.udp6_sock = sock->sk;
902 #endif
903 
904 	return 0;
905 }
906 
907 void sctp_udp_sock_stop(struct net *net)
908 {
909 	if (net->sctp.udp4_sock) {
910 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
911 		net->sctp.udp4_sock = NULL;
912 	}
913 	if (net->sctp.udp6_sock) {
914 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
915 		net->sctp.udp6_sock = NULL;
916 	}
917 }
918 
919 /* Register address family specific functions. */
920 int sctp_register_af(struct sctp_af *af)
921 {
922 	switch (af->sa_family) {
923 	case AF_INET:
924 		if (sctp_af_v4_specific)
925 			return 0;
926 		sctp_af_v4_specific = af;
927 		break;
928 	case AF_INET6:
929 		if (sctp_af_v6_specific)
930 			return 0;
931 		sctp_af_v6_specific = af;
932 		break;
933 	default:
934 		return 0;
935 	}
936 
937 	INIT_LIST_HEAD(&af->list);
938 	list_add_tail(&af->list, &sctp_address_families);
939 	return 1;
940 }
941 
942 /* Get the table of functions for manipulating a particular address
943  * family.
944  */
945 struct sctp_af *sctp_get_af_specific(sa_family_t family)
946 {
947 	switch (family) {
948 	case AF_INET:
949 		return sctp_af_v4_specific;
950 	case AF_INET6:
951 		return sctp_af_v6_specific;
952 	default:
953 		return NULL;
954 	}
955 }
956 
957 /* Common code to initialize a AF_INET msg_name. */
958 static void sctp_inet_msgname(char *msgname, int *addr_len)
959 {
960 	struct sockaddr_in *sin;
961 
962 	sin = (struct sockaddr_in *)msgname;
963 	*addr_len = sizeof(struct sockaddr_in);
964 	sin->sin_family = AF_INET;
965 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
966 }
967 
968 /* Copy the primary address of the peer primary address as the msg_name. */
969 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
970 				    int *addr_len)
971 {
972 	struct sockaddr_in *sin, *sinfrom;
973 
974 	if (msgname) {
975 		struct sctp_association *asoc;
976 
977 		asoc = event->asoc;
978 		sctp_inet_msgname(msgname, addr_len);
979 		sin = (struct sockaddr_in *)msgname;
980 		sinfrom = &asoc->peer.primary_addr.v4;
981 		sin->sin_port = htons(asoc->peer.port);
982 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
983 	}
984 }
985 
986 /* Initialize and copy out a msgname from an inbound skb. */
987 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
988 {
989 	if (msgname) {
990 		struct sctphdr *sh = sctp_hdr(skb);
991 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
992 
993 		sctp_inet_msgname(msgname, len);
994 		sin->sin_port = sh->source;
995 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
996 	}
997 }
998 
999 /* Do we support this AF? */
1000 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1001 {
1002 	/* PF_INET only supports AF_INET addresses. */
1003 	return AF_INET == family;
1004 }
1005 
1006 /* Address matching with wildcards allowed. */
1007 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1008 			      const union sctp_addr *addr2,
1009 			      struct sctp_sock *opt)
1010 {
1011 	/* PF_INET only supports AF_INET addresses. */
1012 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1013 		return 0;
1014 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1015 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1016 		return 1;
1017 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1018 		return 1;
1019 
1020 	return 0;
1021 }
1022 
1023 /* Verify that provided sockaddr looks bindable.  Common verification has
1024  * already been taken care of.
1025  */
1026 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1027 {
1028 	return sctp_v4_available(addr, opt);
1029 }
1030 
1031 /* Verify that sockaddr looks sendable.  Common verification has already
1032  * been taken care of.
1033  */
1034 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1035 {
1036 	return 1;
1037 }
1038 
1039 /* Fill in Supported Address Type information for INIT and INIT-ACK
1040  * chunks.  Returns number of addresses supported.
1041  */
1042 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1043 				     __be16 *types)
1044 {
1045 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1046 	return 1;
1047 }
1048 
1049 /* Wrapper routine that calls the ip transmit routine. */
1050 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1051 {
1052 	struct dst_entry *dst = dst_clone(t->dst);
1053 	struct flowi4 *fl4 = &t->fl.u.ip4;
1054 	struct sock *sk = skb->sk;
1055 	struct inet_sock *inet = inet_sk(sk);
1056 	__u8 dscp = inet->tos;
1057 	__be16 df = 0;
1058 
1059 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1060 		 skb->len, &fl4->saddr, &fl4->daddr);
1061 
1062 	if (t->dscp & SCTP_DSCP_SET_MASK)
1063 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1064 
1065 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1066 							   : IP_PMTUDISC_DONT;
1067 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1068 
1069 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1070 		skb_dst_set(skb, dst);
1071 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1072 	}
1073 
1074 	if (skb_is_gso(skb))
1075 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1076 
1077 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1078 		df = htons(IP_DF);
1079 
1080 	skb->encapsulation = 1;
1081 	skb_reset_inner_mac_header(skb);
1082 	skb_reset_inner_transport_header(skb);
1083 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1084 	udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr,
1085 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1086 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1087 	return 0;
1088 }
1089 
1090 static struct sctp_af sctp_af_inet;
1091 
1092 static struct sctp_pf sctp_pf_inet = {
1093 	.event_msgname = sctp_inet_event_msgname,
1094 	.skb_msgname   = sctp_inet_skb_msgname,
1095 	.af_supported  = sctp_inet_af_supported,
1096 	.cmp_addr      = sctp_inet_cmp_addr,
1097 	.bind_verify   = sctp_inet_bind_verify,
1098 	.send_verify   = sctp_inet_send_verify,
1099 	.supported_addrs = sctp_inet_supported_addrs,
1100 	.create_accept_sk = sctp_v4_create_accept_sk,
1101 	.addr_to_user  = sctp_v4_addr_to_user,
1102 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1103 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1104 	.copy_ip_options = sctp_v4_copy_ip_options,
1105 	.af            = &sctp_af_inet
1106 };
1107 
1108 /* Notifier for inetaddr addition/deletion events.  */
1109 static struct notifier_block sctp_inetaddr_notifier = {
1110 	.notifier_call = sctp_inetaddr_event,
1111 };
1112 
1113 /* Socket operations.  */
1114 static const struct proto_ops inet_seqpacket_ops = {
1115 	.family		   = PF_INET,
1116 	.owner		   = THIS_MODULE,
1117 	.release	   = inet_release,	/* Needs to be wrapped... */
1118 	.bind		   = inet_bind,
1119 	.connect	   = sctp_inet_connect,
1120 	.socketpair	   = sock_no_socketpair,
1121 	.accept		   = inet_accept,
1122 	.getname	   = inet_getname,	/* Semantics are different.  */
1123 	.poll		   = sctp_poll,
1124 	.ioctl		   = inet_ioctl,
1125 	.gettstamp	   = sock_gettstamp,
1126 	.listen		   = sctp_inet_listen,
1127 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1128 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1129 	.getsockopt	   = sock_common_getsockopt,
1130 	.sendmsg	   = inet_sendmsg,
1131 	.recvmsg	   = inet_recvmsg,
1132 	.mmap		   = sock_no_mmap,
1133 	.sendpage	   = sock_no_sendpage,
1134 };
1135 
1136 /* Registration with AF_INET family.  */
1137 static struct inet_protosw sctp_seqpacket_protosw = {
1138 	.type       = SOCK_SEQPACKET,
1139 	.protocol   = IPPROTO_SCTP,
1140 	.prot       = &sctp_prot,
1141 	.ops        = &inet_seqpacket_ops,
1142 	.flags      = SCTP_PROTOSW_FLAG
1143 };
1144 static struct inet_protosw sctp_stream_protosw = {
1145 	.type       = SOCK_STREAM,
1146 	.protocol   = IPPROTO_SCTP,
1147 	.prot       = &sctp_prot,
1148 	.ops        = &inet_seqpacket_ops,
1149 	.flags      = SCTP_PROTOSW_FLAG
1150 };
1151 
1152 static int sctp4_rcv(struct sk_buff *skb)
1153 {
1154 	SCTP_INPUT_CB(skb)->encap_port = 0;
1155 	return sctp_rcv(skb);
1156 }
1157 
1158 /* Register with IP layer.  */
1159 static const struct net_protocol sctp_protocol = {
1160 	.handler     = sctp4_rcv,
1161 	.err_handler = sctp_v4_err,
1162 	.no_policy   = 1,
1163 	.icmp_strict_tag_validation = 1,
1164 };
1165 
1166 /* IPv4 address related functions.  */
1167 static struct sctp_af sctp_af_inet = {
1168 	.sa_family	   = AF_INET,
1169 	.sctp_xmit	   = sctp_v4_xmit,
1170 	.setsockopt	   = ip_setsockopt,
1171 	.getsockopt	   = ip_getsockopt,
1172 	.get_dst	   = sctp_v4_get_dst,
1173 	.get_saddr	   = sctp_v4_get_saddr,
1174 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1175 	.from_skb	   = sctp_v4_from_skb,
1176 	.from_sk	   = sctp_v4_from_sk,
1177 	.from_addr_param   = sctp_v4_from_addr_param,
1178 	.to_addr_param	   = sctp_v4_to_addr_param,
1179 	.cmp_addr	   = sctp_v4_cmp_addr,
1180 	.addr_valid	   = sctp_v4_addr_valid,
1181 	.inaddr_any	   = sctp_v4_inaddr_any,
1182 	.is_any		   = sctp_v4_is_any,
1183 	.available	   = sctp_v4_available,
1184 	.scope		   = sctp_v4_scope,
1185 	.skb_iif	   = sctp_v4_skb_iif,
1186 	.is_ce		   = sctp_v4_is_ce,
1187 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1188 	.ecn_capable	   = sctp_v4_ecn_capable,
1189 	.net_header_len	   = sizeof(struct iphdr),
1190 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1191 	.ip_options_len	   = sctp_v4_ip_options_len,
1192 };
1193 
1194 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1195 {
1196 	switch (family) {
1197 	case PF_INET:
1198 		return sctp_pf_inet_specific;
1199 	case PF_INET6:
1200 		return sctp_pf_inet6_specific;
1201 	default:
1202 		return NULL;
1203 	}
1204 }
1205 
1206 /* Register the PF specific function table.  */
1207 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1208 {
1209 	switch (family) {
1210 	case PF_INET:
1211 		if (sctp_pf_inet_specific)
1212 			return 0;
1213 		sctp_pf_inet_specific = pf;
1214 		break;
1215 	case PF_INET6:
1216 		if (sctp_pf_inet6_specific)
1217 			return 0;
1218 		sctp_pf_inet6_specific = pf;
1219 		break;
1220 	default:
1221 		return 0;
1222 	}
1223 	return 1;
1224 }
1225 
1226 static inline int init_sctp_mibs(struct net *net)
1227 {
1228 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1229 	if (!net->sctp.sctp_statistics)
1230 		return -ENOMEM;
1231 	return 0;
1232 }
1233 
1234 static inline void cleanup_sctp_mibs(struct net *net)
1235 {
1236 	free_percpu(net->sctp.sctp_statistics);
1237 }
1238 
1239 static void sctp_v4_pf_init(void)
1240 {
1241 	/* Initialize the SCTP specific PF functions. */
1242 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1243 	sctp_register_af(&sctp_af_inet);
1244 }
1245 
1246 static void sctp_v4_pf_exit(void)
1247 {
1248 	list_del(&sctp_af_inet.list);
1249 }
1250 
1251 static int sctp_v4_protosw_init(void)
1252 {
1253 	int rc;
1254 
1255 	rc = proto_register(&sctp_prot, 1);
1256 	if (rc)
1257 		return rc;
1258 
1259 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1260 	inet_register_protosw(&sctp_seqpacket_protosw);
1261 	inet_register_protosw(&sctp_stream_protosw);
1262 
1263 	return 0;
1264 }
1265 
1266 static void sctp_v4_protosw_exit(void)
1267 {
1268 	inet_unregister_protosw(&sctp_stream_protosw);
1269 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1270 	proto_unregister(&sctp_prot);
1271 }
1272 
1273 static int sctp_v4_add_protocol(void)
1274 {
1275 	/* Register notifier for inet address additions/deletions. */
1276 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1277 
1278 	/* Register SCTP with inet layer.  */
1279 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1280 		return -EAGAIN;
1281 
1282 	return 0;
1283 }
1284 
1285 static void sctp_v4_del_protocol(void)
1286 {
1287 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1288 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1289 }
1290 
1291 static int __net_init sctp_defaults_init(struct net *net)
1292 {
1293 	int status;
1294 
1295 	/*
1296 	 * 14. Suggested SCTP Protocol Parameter Values
1297 	 */
1298 	/* The following protocol parameters are RECOMMENDED:  */
1299 	/* RTO.Initial              - 3  seconds */
1300 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1301 	/* RTO.Min                  - 1  second */
1302 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1303 	/* RTO.Max                 -  60 seconds */
1304 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1305 	/* RTO.Alpha                - 1/8 */
1306 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1307 	/* RTO.Beta                 - 1/4 */
1308 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1309 
1310 	/* Valid.Cookie.Life        - 60  seconds */
1311 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1312 
1313 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1314 	net->sctp.cookie_preserve_enable 	= 1;
1315 
1316 	/* Default sctp sockets to use md5 as their hmac alg */
1317 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1318 	net->sctp.sctp_hmac_alg			= "md5";
1319 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1320 	net->sctp.sctp_hmac_alg			= "sha1";
1321 #else
1322 	net->sctp.sctp_hmac_alg			= NULL;
1323 #endif
1324 
1325 	/* Max.Burst		    - 4 */
1326 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1327 
1328 	/* Disable of Primary Path Switchover by default */
1329 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1330 
1331 	/* Enable pf state by default */
1332 	net->sctp.pf_enable = 1;
1333 
1334 	/* Ignore pf exposure feature by default */
1335 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1336 
1337 	/* Association.Max.Retrans  - 10 attempts
1338 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1339 	 * Max.Init.Retransmits     - 8  attempts
1340 	 */
1341 	net->sctp.max_retrans_association	= 10;
1342 	net->sctp.max_retrans_path		= 5;
1343 	net->sctp.max_retrans_init		= 8;
1344 
1345 	/* Sendbuffer growth	    - do per-socket accounting */
1346 	net->sctp.sndbuf_policy			= 0;
1347 
1348 	/* Rcvbuffer growth	    - do per-socket accounting */
1349 	net->sctp.rcvbuf_policy			= 0;
1350 
1351 	/* HB.interval              - 30 seconds */
1352 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1353 
1354 	/* delayed SACK timeout */
1355 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1356 
1357 	/* Disable ADDIP by default. */
1358 	net->sctp.addip_enable = 0;
1359 	net->sctp.addip_noauth = 0;
1360 	net->sctp.default_auto_asconf = 0;
1361 
1362 	/* Enable PR-SCTP by default. */
1363 	net->sctp.prsctp_enable = 1;
1364 
1365 	/* Disable RECONF by default. */
1366 	net->sctp.reconf_enable = 0;
1367 
1368 	/* Disable AUTH by default. */
1369 	net->sctp.auth_enable = 0;
1370 
1371 	/* Enable ECN by default. */
1372 	net->sctp.ecn_enable = 1;
1373 
1374 	/* Set UDP tunneling listening port to 0 by default */
1375 	net->sctp.udp_port = 0;
1376 
1377 	/* Set remote encap port to 0 by default */
1378 	net->sctp.encap_port = 0;
1379 
1380 	/* Set SCOPE policy to enabled */
1381 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1382 
1383 	/* Set the default rwnd update threshold */
1384 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1385 
1386 	/* Initialize maximum autoclose timeout. */
1387 	net->sctp.max_autoclose		= INT_MAX / HZ;
1388 
1389 	status = sctp_sysctl_net_register(net);
1390 	if (status)
1391 		goto err_sysctl_register;
1392 
1393 	/* Allocate and initialise sctp mibs.  */
1394 	status = init_sctp_mibs(net);
1395 	if (status)
1396 		goto err_init_mibs;
1397 
1398 #ifdef CONFIG_PROC_FS
1399 	/* Initialize proc fs directory.  */
1400 	status = sctp_proc_init(net);
1401 	if (status)
1402 		goto err_init_proc;
1403 #endif
1404 
1405 	sctp_dbg_objcnt_init(net);
1406 
1407 	/* Initialize the local address list. */
1408 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1409 	spin_lock_init(&net->sctp.local_addr_lock);
1410 	sctp_get_local_addr_list(net);
1411 
1412 	/* Initialize the address event list */
1413 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1414 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1415 	spin_lock_init(&net->sctp.addr_wq_lock);
1416 	net->sctp.addr_wq_timer.expires = 0;
1417 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1418 
1419 	return 0;
1420 
1421 #ifdef CONFIG_PROC_FS
1422 err_init_proc:
1423 	cleanup_sctp_mibs(net);
1424 #endif
1425 err_init_mibs:
1426 	sctp_sysctl_net_unregister(net);
1427 err_sysctl_register:
1428 	return status;
1429 }
1430 
1431 static void __net_exit sctp_defaults_exit(struct net *net)
1432 {
1433 	/* Free the local address list */
1434 	sctp_free_addr_wq(net);
1435 	sctp_free_local_addr_list(net);
1436 
1437 #ifdef CONFIG_PROC_FS
1438 	remove_proc_subtree("sctp", net->proc_net);
1439 	net->sctp.proc_net_sctp = NULL;
1440 #endif
1441 	cleanup_sctp_mibs(net);
1442 	sctp_sysctl_net_unregister(net);
1443 }
1444 
1445 static struct pernet_operations sctp_defaults_ops = {
1446 	.init = sctp_defaults_init,
1447 	.exit = sctp_defaults_exit,
1448 };
1449 
1450 static int __net_init sctp_ctrlsock_init(struct net *net)
1451 {
1452 	int status;
1453 
1454 	/* Initialize the control inode/socket for handling OOTB packets.  */
1455 	status = sctp_ctl_sock_init(net);
1456 	if (status)
1457 		pr_err("Failed to initialize the SCTP control sock\n");
1458 
1459 	return status;
1460 }
1461 
1462 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1463 {
1464 	/* Free the control endpoint.  */
1465 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1466 }
1467 
1468 static struct pernet_operations sctp_ctrlsock_ops = {
1469 	.init = sctp_ctrlsock_init,
1470 	.exit = sctp_ctrlsock_exit,
1471 };
1472 
1473 /* Initialize the universe into something sensible.  */
1474 static __init int sctp_init(void)
1475 {
1476 	unsigned long nr_pages = totalram_pages();
1477 	unsigned long limit;
1478 	unsigned long goal;
1479 	int max_entry_order;
1480 	int num_entries;
1481 	int max_share;
1482 	int status;
1483 	int order;
1484 	int i;
1485 
1486 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1487 
1488 	/* Allocate bind_bucket and chunk caches. */
1489 	status = -ENOBUFS;
1490 	sctp_bucket_cachep = kmem_cache_create("sctp_bind_bucket",
1491 					       sizeof(struct sctp_bind_bucket),
1492 					       0, SLAB_HWCACHE_ALIGN,
1493 					       NULL);
1494 	if (!sctp_bucket_cachep)
1495 		goto out;
1496 
1497 	sctp_chunk_cachep = kmem_cache_create("sctp_chunk",
1498 					       sizeof(struct sctp_chunk),
1499 					       0, SLAB_HWCACHE_ALIGN,
1500 					       NULL);
1501 	if (!sctp_chunk_cachep)
1502 		goto err_chunk_cachep;
1503 
1504 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1505 	if (status)
1506 		goto err_percpu_counter_init;
1507 
1508 	/* Implementation specific variables. */
1509 
1510 	/* Initialize default stream count setup information. */
1511 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1512 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1513 
1514 	/* Initialize handle used for association ids. */
1515 	idr_init(&sctp_assocs_id);
1516 
1517 	limit = nr_free_buffer_pages() / 8;
1518 	limit = max(limit, 128UL);
1519 	sysctl_sctp_mem[0] = limit / 4 * 3;
1520 	sysctl_sctp_mem[1] = limit;
1521 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1522 
1523 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1524 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1525 	max_share = min(4UL*1024*1024, limit);
1526 
1527 	sysctl_sctp_rmem[0] = SK_MEM_QUANTUM; /* give each asoc 1 page min */
1528 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1529 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1530 
1531 	sysctl_sctp_wmem[0] = SK_MEM_QUANTUM;
1532 	sysctl_sctp_wmem[1] = 16*1024;
1533 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1534 
1535 	/* Size and allocate the association hash table.
1536 	 * The methodology is similar to that of the tcp hash tables.
1537 	 * Though not identical.  Start by getting a goal size
1538 	 */
1539 	if (nr_pages >= (128 * 1024))
1540 		goal = nr_pages >> (22 - PAGE_SHIFT);
1541 	else
1542 		goal = nr_pages >> (24 - PAGE_SHIFT);
1543 
1544 	/* Then compute the page order for said goal */
1545 	order = get_order(goal);
1546 
1547 	/* Now compute the required page order for the maximum sized table we
1548 	 * want to create
1549 	 */
1550 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1551 				    sizeof(struct sctp_bind_hashbucket));
1552 
1553 	/* Limit the page order by that maximum hash table size */
1554 	order = min(order, max_entry_order);
1555 
1556 	/* Allocate and initialize the endpoint hash table.  */
1557 	sctp_ep_hashsize = 64;
1558 	sctp_ep_hashtable =
1559 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1560 	if (!sctp_ep_hashtable) {
1561 		pr_err("Failed endpoint_hash alloc\n");
1562 		status = -ENOMEM;
1563 		goto err_ehash_alloc;
1564 	}
1565 	for (i = 0; i < sctp_ep_hashsize; i++) {
1566 		rwlock_init(&sctp_ep_hashtable[i].lock);
1567 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1568 	}
1569 
1570 	/* Allocate and initialize the SCTP port hash table.
1571 	 * Note that order is initalized to start at the max sized
1572 	 * table we want to support.  If we can't get that many pages
1573 	 * reduce the order and try again
1574 	 */
1575 	do {
1576 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1577 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1578 	} while (!sctp_port_hashtable && --order > 0);
1579 
1580 	if (!sctp_port_hashtable) {
1581 		pr_err("Failed bind hash alloc\n");
1582 		status = -ENOMEM;
1583 		goto err_bhash_alloc;
1584 	}
1585 
1586 	/* Now compute the number of entries that will fit in the
1587 	 * port hash space we allocated
1588 	 */
1589 	num_entries = (1UL << order) * PAGE_SIZE /
1590 		      sizeof(struct sctp_bind_hashbucket);
1591 
1592 	/* And finish by rounding it down to the nearest power of two.
1593 	 * This wastes some memory of course, but it's needed because
1594 	 * the hash function operates based on the assumption that
1595 	 * the number of entries is a power of two.
1596 	 */
1597 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1598 
1599 	for (i = 0; i < sctp_port_hashsize; i++) {
1600 		spin_lock_init(&sctp_port_hashtable[i].lock);
1601 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1602 	}
1603 
1604 	status = sctp_transport_hashtable_init();
1605 	if (status)
1606 		goto err_thash_alloc;
1607 
1608 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1609 		num_entries);
1610 
1611 	sctp_sysctl_register();
1612 
1613 	INIT_LIST_HEAD(&sctp_address_families);
1614 	sctp_v4_pf_init();
1615 	sctp_v6_pf_init();
1616 	sctp_sched_ops_init();
1617 
1618 	status = register_pernet_subsys(&sctp_defaults_ops);
1619 	if (status)
1620 		goto err_register_defaults;
1621 
1622 	status = sctp_v4_protosw_init();
1623 	if (status)
1624 		goto err_protosw_init;
1625 
1626 	status = sctp_v6_protosw_init();
1627 	if (status)
1628 		goto err_v6_protosw_init;
1629 
1630 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1631 	if (status)
1632 		goto err_register_ctrlsock;
1633 
1634 	status = sctp_v4_add_protocol();
1635 	if (status)
1636 		goto err_add_protocol;
1637 
1638 	/* Register SCTP with inet6 layer.  */
1639 	status = sctp_v6_add_protocol();
1640 	if (status)
1641 		goto err_v6_add_protocol;
1642 
1643 	if (sctp_offload_init() < 0)
1644 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1645 
1646 out:
1647 	return status;
1648 err_v6_add_protocol:
1649 	sctp_v4_del_protocol();
1650 err_add_protocol:
1651 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1652 err_register_ctrlsock:
1653 	sctp_v6_protosw_exit();
1654 err_v6_protosw_init:
1655 	sctp_v4_protosw_exit();
1656 err_protosw_init:
1657 	unregister_pernet_subsys(&sctp_defaults_ops);
1658 err_register_defaults:
1659 	sctp_v4_pf_exit();
1660 	sctp_v6_pf_exit();
1661 	sctp_sysctl_unregister();
1662 	free_pages((unsigned long)sctp_port_hashtable,
1663 		   get_order(sctp_port_hashsize *
1664 			     sizeof(struct sctp_bind_hashbucket)));
1665 err_bhash_alloc:
1666 	sctp_transport_hashtable_destroy();
1667 err_thash_alloc:
1668 	kfree(sctp_ep_hashtable);
1669 err_ehash_alloc:
1670 	percpu_counter_destroy(&sctp_sockets_allocated);
1671 err_percpu_counter_init:
1672 	kmem_cache_destroy(sctp_chunk_cachep);
1673 err_chunk_cachep:
1674 	kmem_cache_destroy(sctp_bucket_cachep);
1675 	goto out;
1676 }
1677 
1678 /* Exit handler for the SCTP protocol.  */
1679 static __exit void sctp_exit(void)
1680 {
1681 	/* BUG.  This should probably do something useful like clean
1682 	 * up all the remaining associations and all that memory.
1683 	 */
1684 
1685 	/* Unregister with inet6/inet layers. */
1686 	sctp_v6_del_protocol();
1687 	sctp_v4_del_protocol();
1688 
1689 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1690 
1691 	/* Free protosw registrations */
1692 	sctp_v6_protosw_exit();
1693 	sctp_v4_protosw_exit();
1694 
1695 	unregister_pernet_subsys(&sctp_defaults_ops);
1696 
1697 	/* Unregister with socket layer. */
1698 	sctp_v6_pf_exit();
1699 	sctp_v4_pf_exit();
1700 
1701 	sctp_sysctl_unregister();
1702 
1703 	free_pages((unsigned long)sctp_port_hashtable,
1704 		   get_order(sctp_port_hashsize *
1705 			     sizeof(struct sctp_bind_hashbucket)));
1706 	kfree(sctp_ep_hashtable);
1707 	sctp_transport_hashtable_destroy();
1708 
1709 	percpu_counter_destroy(&sctp_sockets_allocated);
1710 
1711 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1712 
1713 	kmem_cache_destroy(sctp_chunk_cachep);
1714 	kmem_cache_destroy(sctp_bucket_cachep);
1715 }
1716 
1717 module_init(sctp_init);
1718 module_exit(sctp_exit);
1719 
1720 /*
1721  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1722  */
1723 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1724 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1725 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1726 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1727 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1728 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1729 MODULE_LICENSE("GPL");
1730