xref: /linux/net/sctp/protocol.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001 Intel Corp.
7  * Copyright (c) 2001 Nokia, Inc.
8  * Copyright (c) 2001 La Monte H.P. Yarroll
9  *
10  * This file is part of the SCTP kernel implementation
11  *
12  * Initialization/cleanup for SCTP protocol support.
13  *
14  * Please send any bug reports or fixes you make to the
15  * email address(es):
16  *    lksctp developers <linux-sctp@vger.kernel.org>
17  *
18  * Written or modified by:
19  *    La Monte H.P. Yarroll <piggy@acm.org>
20  *    Karl Knutson <karl@athena.chicago.il.us>
21  *    Jon Grimm <jgrimm@us.ibm.com>
22  *    Sridhar Samudrala <sri@us.ibm.com>
23  *    Daisy Chang <daisyc@us.ibm.com>
24  *    Ardelle Fan <ardelle.fan@intel.com>
25  */
26 
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28 
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/netdevice.h>
32 #include <linux/inetdevice.h>
33 #include <linux/seq_file.h>
34 #include <linux/memblock.h>
35 #include <linux/highmem.h>
36 #include <linux/slab.h>
37 #include <net/net_namespace.h>
38 #include <net/protocol.h>
39 #include <net/ip.h>
40 #include <net/ipv6.h>
41 #include <net/route.h>
42 #include <net/sctp/sctp.h>
43 #include <net/addrconf.h>
44 #include <net/inet_common.h>
45 #include <net/inet_ecn.h>
46 #include <net/udp_tunnel.h>
47 #include <net/inet_dscp.h>
48 
49 #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024)
50 
51 /* Global data structures. */
52 struct sctp_globals sctp_globals __read_mostly;
53 
54 struct idr sctp_assocs_id;
55 DEFINE_SPINLOCK(sctp_assocs_id_lock);
56 
57 static struct sctp_pf *sctp_pf_inet6_specific;
58 static struct sctp_pf *sctp_pf_inet_specific;
59 static struct sctp_af *sctp_af_v4_specific;
60 static struct sctp_af *sctp_af_v6_specific;
61 
62 struct kmem_cache *sctp_chunk_cachep __read_mostly;
63 struct kmem_cache *sctp_bucket_cachep __read_mostly;
64 
65 long sysctl_sctp_mem[3];
66 int sysctl_sctp_rmem[3];
67 int sysctl_sctp_wmem[3];
68 
69 /* Private helper to extract ipv4 address and stash them in
70  * the protocol structure.
71  */
72 static void sctp_v4_copy_addrlist(struct list_head *addrlist,
73 				  struct net_device *dev)
74 {
75 	struct in_device *in_dev;
76 	struct in_ifaddr *ifa;
77 	struct sctp_sockaddr_entry *addr;
78 
79 	rcu_read_lock();
80 	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
81 		rcu_read_unlock();
82 		return;
83 	}
84 
85 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
86 		/* Add the address to the local list.  */
87 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
88 		if (addr) {
89 			addr->a.v4.sin_family = AF_INET;
90 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
91 			addr->valid = 1;
92 			INIT_LIST_HEAD(&addr->list);
93 			list_add_tail(&addr->list, addrlist);
94 		}
95 	}
96 
97 	rcu_read_unlock();
98 }
99 
100 /* Extract our IP addresses from the system and stash them in the
101  * protocol structure.
102  */
103 static void sctp_get_local_addr_list(struct net *net)
104 {
105 	struct net_device *dev;
106 	struct list_head *pos;
107 	struct sctp_af *af;
108 
109 	rcu_read_lock();
110 	for_each_netdev_rcu(net, dev) {
111 		list_for_each(pos, &sctp_address_families) {
112 			af = list_entry(pos, struct sctp_af, list);
113 			af->copy_addrlist(&net->sctp.local_addr_list, dev);
114 		}
115 	}
116 	rcu_read_unlock();
117 }
118 
119 /* Free the existing local addresses.  */
120 static void sctp_free_local_addr_list(struct net *net)
121 {
122 	struct sctp_sockaddr_entry *addr;
123 	struct list_head *pos, *temp;
124 
125 	list_for_each_safe(pos, temp, &net->sctp.local_addr_list) {
126 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
127 		list_del(pos);
128 		kfree(addr);
129 	}
130 }
131 
132 /* Copy the local addresses which are valid for 'scope' into 'bp'.  */
133 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
134 			      enum sctp_scope scope, gfp_t gfp, int copy_flags)
135 {
136 	struct sctp_sockaddr_entry *addr;
137 	union sctp_addr laddr;
138 	int error = 0;
139 
140 	rcu_read_lock();
141 	list_for_each_entry_rcu(addr, &net->sctp.local_addr_list, list) {
142 		if (!addr->valid)
143 			continue;
144 		if (!sctp_in_scope(net, &addr->a, scope))
145 			continue;
146 
147 		/* Now that the address is in scope, check to see if
148 		 * the address type is really supported by the local
149 		 * sock as well as the remote peer.
150 		 */
151 		if (addr->a.sa.sa_family == AF_INET &&
152 		    (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
153 		     !(copy_flags & SCTP_ADDR4_PEERSUPP)))
154 			continue;
155 		if (addr->a.sa.sa_family == AF_INET6 &&
156 		    (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
157 		     !(copy_flags & SCTP_ADDR6_PEERSUPP)))
158 			continue;
159 
160 		laddr = addr->a;
161 		/* also works for setting ipv6 address port */
162 		laddr.v4.sin_port = htons(bp->port);
163 		if (sctp_bind_addr_state(bp, &laddr) != -1)
164 			continue;
165 
166 		error = sctp_add_bind_addr(bp, &addr->a, sizeof(addr->a),
167 					   SCTP_ADDR_SRC, GFP_ATOMIC);
168 		if (error)
169 			break;
170 	}
171 
172 	rcu_read_unlock();
173 	return error;
174 }
175 
176 /* Copy over any ip options */
177 static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
178 {
179 	struct inet_sock *newinet, *inet = inet_sk(sk);
180 	struct ip_options_rcu *inet_opt, *newopt = NULL;
181 
182 	newinet = inet_sk(newsk);
183 
184 	rcu_read_lock();
185 	inet_opt = rcu_dereference(inet->inet_opt);
186 	if (inet_opt) {
187 		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
188 				      inet_opt->opt.optlen, GFP_ATOMIC);
189 		if (newopt)
190 			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
191 			       inet_opt->opt.optlen);
192 		else
193 			pr_err("%s: Failed to copy ip options\n", __func__);
194 	}
195 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
196 	rcu_read_unlock();
197 }
198 
199 /* Account for the IP options */
200 static int sctp_v4_ip_options_len(struct sock *sk)
201 {
202 	struct inet_sock *inet = inet_sk(sk);
203 	struct ip_options_rcu *inet_opt;
204 	int len = 0;
205 
206 	rcu_read_lock();
207 	inet_opt = rcu_dereference(inet->inet_opt);
208 	if (inet_opt)
209 		len = inet_opt->opt.optlen;
210 
211 	rcu_read_unlock();
212 	return len;
213 }
214 
215 /* Initialize a sctp_addr from in incoming skb.  */
216 static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
217 			     int is_saddr)
218 {
219 	/* Always called on head skb, so this is safe */
220 	struct sctphdr *sh = sctp_hdr(skb);
221 	struct sockaddr_in *sa = &addr->v4;
222 
223 	addr->v4.sin_family = AF_INET;
224 
225 	if (is_saddr) {
226 		sa->sin_port = sh->source;
227 		sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
228 	} else {
229 		sa->sin_port = sh->dest;
230 		sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
231 	}
232 	memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
233 }
234 
235 /* Initialize an sctp_addr from a socket. */
236 static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
237 {
238 	addr->v4.sin_family = AF_INET;
239 	addr->v4.sin_port = 0;
240 	addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
241 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
242 }
243 
244 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
245 static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
246 {
247 	inet_sk(sk)->inet_rcv_saddr = addr->v4.sin_addr.s_addr;
248 }
249 
250 /* Initialize sk->sk_daddr from sctp_addr. */
251 static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
252 {
253 	inet_sk(sk)->inet_daddr = addr->v4.sin_addr.s_addr;
254 }
255 
256 /* Initialize a sctp_addr from an address parameter. */
257 static bool sctp_v4_from_addr_param(union sctp_addr *addr,
258 				    union sctp_addr_param *param,
259 				    __be16 port, int iif)
260 {
261 	if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
262 		return false;
263 
264 	addr->v4.sin_family = AF_INET;
265 	addr->v4.sin_port = port;
266 	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
267 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
268 
269 	return true;
270 }
271 
272 /* Initialize an address parameter from a sctp_addr and return the length
273  * of the address parameter.
274  */
275 static int sctp_v4_to_addr_param(const union sctp_addr *addr,
276 				 union sctp_addr_param *param)
277 {
278 	int length = sizeof(struct sctp_ipv4addr_param);
279 
280 	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
281 	param->v4.param_hdr.length = htons(length);
282 	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;
283 
284 	return length;
285 }
286 
287 /* Initialize a sctp_addr from a dst_entry. */
288 static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct flowi4 *fl4,
289 			      __be16 port)
290 {
291 	saddr->v4.sin_family = AF_INET;
292 	saddr->v4.sin_port = port;
293 	saddr->v4.sin_addr.s_addr = fl4->saddr;
294 	memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
295 }
296 
297 /* Compare two addresses exactly. */
298 static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
299 			    const union sctp_addr *addr2)
300 {
301 	if (addr1->sa.sa_family != addr2->sa.sa_family)
302 		return 0;
303 	if (addr1->v4.sin_port != addr2->v4.sin_port)
304 		return 0;
305 	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
306 		return 0;
307 
308 	return 1;
309 }
310 
311 /* Initialize addr struct to INADDR_ANY. */
312 static void sctp_v4_inaddr_any(union sctp_addr *addr, __be16 port)
313 {
314 	addr->v4.sin_family = AF_INET;
315 	addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
316 	addr->v4.sin_port = port;
317 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
318 }
319 
320 /* Is this a wildcard address? */
321 static int sctp_v4_is_any(const union sctp_addr *addr)
322 {
323 	return htonl(INADDR_ANY) == addr->v4.sin_addr.s_addr;
324 }
325 
326 /* This function checks if the address is a valid address to be used for
327  * SCTP binding.
328  *
329  * Output:
330  * Return 0 - If the address is a non-unicast or an illegal address.
331  * Return 1 - If the address is a unicast.
332  */
333 static int sctp_v4_addr_valid(union sctp_addr *addr,
334 			      struct sctp_sock *sp,
335 			      const struct sk_buff *skb)
336 {
337 	/* IPv4 addresses not allowed */
338 	if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
339 		return 0;
340 
341 	/* Is this a non-unicast address or a unusable SCTP address? */
342 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr))
343 		return 0;
344 
345 	/* Is this a broadcast address? */
346 	if (skb && skb_rtable(skb)->rt_flags & RTCF_BROADCAST)
347 		return 0;
348 
349 	return 1;
350 }
351 
352 /* Should this be available for binding?   */
353 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
354 {
355 	struct sock *sk = &sp->inet.sk;
356 	struct net *net = sock_net(sk);
357 	int tb_id = RT_TABLE_LOCAL;
358 	int ret;
359 
360 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
361 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
362 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
363 	   ret != RTN_LOCAL &&
364 	   !inet_test_bit(FREEBIND, sk) &&
365 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
366 		return 0;
367 
368 	if (ipv6_only_sock(sctp_opt2sk(sp)))
369 		return 0;
370 
371 	return 1;
372 }
373 
374 /* Checking the loopback, private and other address scopes as defined in
375  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
376  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
377  *
378  * Level 0 - unusable SCTP addresses
379  * Level 1 - loopback address
380  * Level 2 - link-local addresses
381  * Level 3 - private addresses.
382  * Level 4 - global addresses
383  * For INIT and INIT-ACK address list, let L be the level of
384  * requested destination address, sender and receiver
385  * SHOULD include all of its addresses with level greater
386  * than or equal to L.
387  *
388  * IPv4 scoping can be controlled through sysctl option
389  * net.sctp.addr_scope_policy
390  */
391 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
392 {
393 	enum sctp_scope retval;
394 
395 	/* Check for unusable SCTP addresses. */
396 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
397 		retval =  SCTP_SCOPE_UNUSABLE;
398 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
399 		retval = SCTP_SCOPE_LOOPBACK;
400 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
401 		retval = SCTP_SCOPE_LINK;
402 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
403 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
404 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
405 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
406 		retval = SCTP_SCOPE_PRIVATE;
407 	} else {
408 		retval = SCTP_SCOPE_GLOBAL;
409 	}
410 
411 	return retval;
412 }
413 
414 /* Returns a valid dst cache entry for the given source and destination ip
415  * addresses. If an association is passed, trys to get a dst entry with a
416  * source address that matches an address in the bind address list.
417  */
418 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
419 				struct flowi *fl, struct sock *sk)
420 {
421 	struct sctp_association *asoc = t->asoc;
422 	struct rtable *rt;
423 	struct flowi _fl;
424 	struct flowi4 *fl4 = &_fl.u.ip4;
425 	struct sctp_bind_addr *bp;
426 	struct sctp_sockaddr_entry *laddr;
427 	struct dst_entry *dst = NULL;
428 	union sctp_addr *daddr = &t->ipaddr;
429 	union sctp_addr dst_saddr;
430 	u8 tos = READ_ONCE(inet_sk(sk)->tos);
431 
432 	if (t->dscp & SCTP_DSCP_SET_MASK)
433 		tos = t->dscp & SCTP_DSCP_VAL_MASK;
434 	memset(&_fl, 0x0, sizeof(_fl));
435 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
436 	fl4->fl4_dport = daddr->v4.sin_port;
437 	fl4->flowi4_proto = IPPROTO_SCTP;
438 	if (asoc) {
439 		fl4->flowi4_tos = tos & INET_DSCP_MASK;
440 		fl4->flowi4_scope = ip_sock_rt_scope(asoc->base.sk);
441 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
442 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
443 	}
444 	if (saddr) {
445 		fl4->saddr = saddr->v4.sin_addr.s_addr;
446 		if (!fl4->fl4_sport)
447 			fl4->fl4_sport = saddr->v4.sin_port;
448 	}
449 
450 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
451 		 &fl4->saddr);
452 
453 	rt = ip_route_output_key(sock_net(sk), fl4);
454 	if (!IS_ERR(rt)) {
455 		dst = &rt->dst;
456 		t->dst = dst;
457 		memcpy(fl, &_fl, sizeof(_fl));
458 	}
459 
460 	/* If there is no association or if a source address is passed, no
461 	 * more validation is required.
462 	 */
463 	if (!asoc || saddr)
464 		goto out;
465 
466 	bp = &asoc->base.bind_addr;
467 
468 	if (dst) {
469 		/* Walk through the bind address list and look for a bind
470 		 * address that matches the source address of the returned dst.
471 		 */
472 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
473 		rcu_read_lock();
474 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
475 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
476 			    (laddr->state != SCTP_ADDR_SRC &&
477 			    !asoc->src_out_of_asoc_ok))
478 				continue;
479 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
480 				goto out_unlock;
481 		}
482 		rcu_read_unlock();
483 
484 		/* None of the bound addresses match the source address of the
485 		 * dst. So release it.
486 		 */
487 		dst_release(dst);
488 		dst = NULL;
489 	}
490 
491 	/* Walk through the bind address list and try to get a dst that
492 	 * matches a bind address as the source address.
493 	 */
494 	rcu_read_lock();
495 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
496 		struct net_device *odev;
497 
498 		if (!laddr->valid)
499 			continue;
500 		if (laddr->state != SCTP_ADDR_SRC ||
501 		    AF_INET != laddr->a.sa.sa_family)
502 			continue;
503 
504 		fl4->fl4_sport = laddr->a.v4.sin_port;
505 		flowi4_update_output(fl4, asoc->base.sk->sk_bound_dev_if,
506 				     daddr->v4.sin_addr.s_addr,
507 				     laddr->a.v4.sin_addr.s_addr);
508 
509 		rt = ip_route_output_key(sock_net(sk), fl4);
510 		if (IS_ERR(rt))
511 			continue;
512 
513 		/* Ensure the src address belongs to the output
514 		 * interface.
515 		 */
516 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
517 				     false);
518 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
519 			if (!dst) {
520 				dst = &rt->dst;
521 				t->dst = dst;
522 				memcpy(fl, &_fl, sizeof(_fl));
523 			} else {
524 				dst_release(&rt->dst);
525 			}
526 			continue;
527 		}
528 
529 		dst_release(dst);
530 		dst = &rt->dst;
531 		t->dst = dst;
532 		memcpy(fl, &_fl, sizeof(_fl));
533 		break;
534 	}
535 
536 out_unlock:
537 	rcu_read_unlock();
538 out:
539 	if (dst) {
540 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
541 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
542 	} else {
543 		t->dst = NULL;
544 		pr_debug("no route\n");
545 	}
546 }
547 
548 /* For v4, the source address is cached in the route entry(dst). So no need
549  * to cache it separately and hence this is an empty routine.
550  */
551 static void sctp_v4_get_saddr(struct sctp_sock *sk,
552 			      struct sctp_transport *t,
553 			      struct flowi *fl)
554 {
555 	union sctp_addr *saddr = &t->saddr;
556 	struct rtable *rt = dst_rtable(t->dst);
557 
558 	if (rt) {
559 		saddr->v4.sin_family = AF_INET;
560 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
561 	}
562 }
563 
564 /* What interface did this skb arrive on? */
565 static int sctp_v4_skb_iif(const struct sk_buff *skb)
566 {
567 	return inet_iif(skb);
568 }
569 
570 static int sctp_v4_skb_sdif(const struct sk_buff *skb)
571 {
572 	return inet_sdif(skb);
573 }
574 
575 /* Was this packet marked by Explicit Congestion Notification? */
576 static int sctp_v4_is_ce(const struct sk_buff *skb)
577 {
578 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
579 }
580 
581 /* Create and initialize a new sk for the socket returned by accept(). */
582 static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
583 					     struct sctp_association *asoc,
584 					     bool kern)
585 {
586 	struct sock *newsk = sk_alloc(sock_net(sk), PF_INET, GFP_KERNEL,
587 			sk->sk_prot, kern);
588 	struct inet_sock *newinet;
589 
590 	if (!newsk)
591 		goto out;
592 
593 	sock_init_data(NULL, newsk);
594 
595 	sctp_copy_sock(newsk, sk, asoc);
596 	sock_reset_flag(newsk, SOCK_ZAPPED);
597 
598 	sctp_v4_copy_ip_options(sk, newsk);
599 
600 	newinet = inet_sk(newsk);
601 
602 	newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
603 
604 	if (newsk->sk_prot->init(newsk)) {
605 		sk_common_release(newsk);
606 		newsk = NULL;
607 	}
608 
609 out:
610 	return newsk;
611 }
612 
613 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
614 {
615 	/* No address mapping for V4 sockets */
616 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
617 	return sizeof(struct sockaddr_in);
618 }
619 
620 /* Dump the v4 addr to the seq file. */
621 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
622 {
623 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
624 }
625 
626 static void sctp_v4_ecn_capable(struct sock *sk)
627 {
628 	INET_ECN_xmit(sk);
629 }
630 
631 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
632 {
633 	struct net *net = from_timer(net, t, sctp.addr_wq_timer);
634 	struct sctp_sockaddr_entry *addrw, *temp;
635 	struct sctp_sock *sp;
636 
637 	spin_lock_bh(&net->sctp.addr_wq_lock);
638 
639 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
640 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
641 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
642 			 addrw->state, addrw);
643 
644 #if IS_ENABLED(CONFIG_IPV6)
645 		/* Now we send an ASCONF for each association */
646 		/* Note. we currently don't handle link local IPv6 addressees */
647 		if (addrw->a.sa.sa_family == AF_INET6) {
648 			struct in6_addr *in6;
649 
650 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
651 			    IPV6_ADDR_LINKLOCAL)
652 				goto free_next;
653 
654 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
655 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
656 			    addrw->state == SCTP_ADDR_NEW) {
657 				unsigned long timeo_val;
658 
659 				pr_debug("%s: this is on DAD, trying %d sec "
660 					 "later\n", __func__,
661 					 SCTP_ADDRESS_TICK_DELAY);
662 
663 				timeo_val = jiffies;
664 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
665 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
666 				break;
667 			}
668 		}
669 #endif
670 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
671 			struct sock *sk;
672 
673 			sk = sctp_opt2sk(sp);
674 			/* ignore bound-specific endpoints */
675 			if (!sctp_is_ep_boundall(sk))
676 				continue;
677 			bh_lock_sock(sk);
678 			if (sctp_asconf_mgmt(sp, addrw) < 0)
679 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
680 			bh_unlock_sock(sk);
681 		}
682 #if IS_ENABLED(CONFIG_IPV6)
683 free_next:
684 #endif
685 		list_del(&addrw->list);
686 		kfree(addrw);
687 	}
688 	spin_unlock_bh(&net->sctp.addr_wq_lock);
689 }
690 
691 static void sctp_free_addr_wq(struct net *net)
692 {
693 	struct sctp_sockaddr_entry *addrw;
694 	struct sctp_sockaddr_entry *temp;
695 
696 	spin_lock_bh(&net->sctp.addr_wq_lock);
697 	del_timer(&net->sctp.addr_wq_timer);
698 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
699 		list_del(&addrw->list);
700 		kfree(addrw);
701 	}
702 	spin_unlock_bh(&net->sctp.addr_wq_lock);
703 }
704 
705 /* lookup the entry for the same address in the addr_waitq
706  * sctp_addr_wq MUST be locked
707  */
708 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
709 					struct sctp_sockaddr_entry *addr)
710 {
711 	struct sctp_sockaddr_entry *addrw;
712 
713 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
714 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
715 			continue;
716 		if (addrw->a.sa.sa_family == AF_INET) {
717 			if (addrw->a.v4.sin_addr.s_addr ==
718 			    addr->a.v4.sin_addr.s_addr)
719 				return addrw;
720 		} else if (addrw->a.sa.sa_family == AF_INET6) {
721 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
722 			    &addr->a.v6.sin6_addr))
723 				return addrw;
724 		}
725 	}
726 	return NULL;
727 }
728 
729 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
730 {
731 	struct sctp_sockaddr_entry *addrw;
732 	unsigned long timeo_val;
733 
734 	/* first, we check if an opposite message already exist in the queue.
735 	 * If we found such message, it is removed.
736 	 * This operation is a bit stupid, but the DHCP client attaches the
737 	 * new address after a couple of addition and deletion of that address
738 	 */
739 
740 	spin_lock_bh(&net->sctp.addr_wq_lock);
741 	/* Offsets existing events in addr_wq */
742 	addrw = sctp_addr_wq_lookup(net, addr);
743 	if (addrw) {
744 		if (addrw->state != cmd) {
745 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
746 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
747 				 &net->sctp.addr_waitq);
748 
749 			list_del(&addrw->list);
750 			kfree(addrw);
751 		}
752 		spin_unlock_bh(&net->sctp.addr_wq_lock);
753 		return;
754 	}
755 
756 	/* OK, we have to add the new address to the wait queue */
757 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
758 	if (addrw == NULL) {
759 		spin_unlock_bh(&net->sctp.addr_wq_lock);
760 		return;
761 	}
762 	addrw->state = cmd;
763 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
764 
765 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
766 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
767 
768 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
769 		timeo_val = jiffies;
770 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
771 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
772 	}
773 	spin_unlock_bh(&net->sctp.addr_wq_lock);
774 }
775 
776 /* Event handler for inet address addition/deletion events.
777  * The sctp_local_addr_list needs to be protocted by a spin lock since
778  * multiple notifiers (say IPv4 and IPv6) may be running at the same
779  * time and thus corrupt the list.
780  * The reader side is protected with RCU.
781  */
782 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
783 			       void *ptr)
784 {
785 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
786 	struct sctp_sockaddr_entry *addr = NULL;
787 	struct sctp_sockaddr_entry *temp;
788 	struct net *net = dev_net(ifa->ifa_dev->dev);
789 	int found = 0;
790 
791 	switch (ev) {
792 	case NETDEV_UP:
793 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
794 		if (addr) {
795 			addr->a.v4.sin_family = AF_INET;
796 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
797 			addr->valid = 1;
798 			spin_lock_bh(&net->sctp.local_addr_lock);
799 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
800 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
801 			spin_unlock_bh(&net->sctp.local_addr_lock);
802 		}
803 		break;
804 	case NETDEV_DOWN:
805 		spin_lock_bh(&net->sctp.local_addr_lock);
806 		list_for_each_entry_safe(addr, temp,
807 					&net->sctp.local_addr_list, list) {
808 			if (addr->a.sa.sa_family == AF_INET &&
809 					addr->a.v4.sin_addr.s_addr ==
810 					ifa->ifa_local) {
811 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
812 				found = 1;
813 				addr->valid = 0;
814 				list_del_rcu(&addr->list);
815 				break;
816 			}
817 		}
818 		spin_unlock_bh(&net->sctp.local_addr_lock);
819 		if (found)
820 			kfree_rcu(addr, rcu);
821 		break;
822 	}
823 
824 	return NOTIFY_DONE;
825 }
826 
827 /*
828  * Initialize the control inode/socket with a control endpoint data
829  * structure.  This endpoint is reserved exclusively for the OOTB processing.
830  */
831 static int sctp_ctl_sock_init(struct net *net)
832 {
833 	int err;
834 	sa_family_t family = PF_INET;
835 
836 	if (sctp_get_pf_specific(PF_INET6))
837 		family = PF_INET6;
838 
839 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
840 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
841 
842 	/* If IPv6 socket could not be created, try the IPv4 socket */
843 	if (err < 0 && family == PF_INET6)
844 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
845 					   SOCK_SEQPACKET, IPPROTO_SCTP,
846 					   net);
847 
848 	if (err < 0) {
849 		pr_err("Failed to create the SCTP control socket\n");
850 		return err;
851 	}
852 	return 0;
853 }
854 
855 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
856 {
857 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
858 
859 	skb_set_transport_header(skb, sizeof(struct udphdr));
860 	sctp_rcv(skb);
861 	return 0;
862 }
863 
864 int sctp_udp_sock_start(struct net *net)
865 {
866 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
867 	struct udp_port_cfg udp_conf = {0};
868 	struct socket *sock;
869 	int err;
870 
871 	udp_conf.family = AF_INET;
872 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
873 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
874 	err = udp_sock_create(net, &udp_conf, &sock);
875 	if (err) {
876 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
877 		return err;
878 	}
879 
880 	tuncfg.encap_type = 1;
881 	tuncfg.encap_rcv = sctp_udp_rcv;
882 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
883 	setup_udp_tunnel_sock(net, sock, &tuncfg);
884 	net->sctp.udp4_sock = sock->sk;
885 
886 #if IS_ENABLED(CONFIG_IPV6)
887 	memset(&udp_conf, 0, sizeof(udp_conf));
888 
889 	udp_conf.family = AF_INET6;
890 	udp_conf.local_ip6 = in6addr_any;
891 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
892 	udp_conf.use_udp6_rx_checksums = true;
893 	udp_conf.ipv6_v6only = true;
894 	err = udp_sock_create(net, &udp_conf, &sock);
895 	if (err) {
896 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
897 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
898 		net->sctp.udp4_sock = NULL;
899 		return err;
900 	}
901 
902 	tuncfg.encap_type = 1;
903 	tuncfg.encap_rcv = sctp_udp_rcv;
904 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
905 	setup_udp_tunnel_sock(net, sock, &tuncfg);
906 	net->sctp.udp6_sock = sock->sk;
907 #endif
908 
909 	return 0;
910 }
911 
912 void sctp_udp_sock_stop(struct net *net)
913 {
914 	if (net->sctp.udp4_sock) {
915 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
916 		net->sctp.udp4_sock = NULL;
917 	}
918 	if (net->sctp.udp6_sock) {
919 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
920 		net->sctp.udp6_sock = NULL;
921 	}
922 }
923 
924 /* Register address family specific functions. */
925 int sctp_register_af(struct sctp_af *af)
926 {
927 	switch (af->sa_family) {
928 	case AF_INET:
929 		if (sctp_af_v4_specific)
930 			return 0;
931 		sctp_af_v4_specific = af;
932 		break;
933 	case AF_INET6:
934 		if (sctp_af_v6_specific)
935 			return 0;
936 		sctp_af_v6_specific = af;
937 		break;
938 	default:
939 		return 0;
940 	}
941 
942 	INIT_LIST_HEAD(&af->list);
943 	list_add_tail(&af->list, &sctp_address_families);
944 	return 1;
945 }
946 
947 /* Get the table of functions for manipulating a particular address
948  * family.
949  */
950 struct sctp_af *sctp_get_af_specific(sa_family_t family)
951 {
952 	switch (family) {
953 	case AF_INET:
954 		return sctp_af_v4_specific;
955 	case AF_INET6:
956 		return sctp_af_v6_specific;
957 	default:
958 		return NULL;
959 	}
960 }
961 
962 /* Common code to initialize a AF_INET msg_name. */
963 static void sctp_inet_msgname(char *msgname, int *addr_len)
964 {
965 	struct sockaddr_in *sin;
966 
967 	sin = (struct sockaddr_in *)msgname;
968 	*addr_len = sizeof(struct sockaddr_in);
969 	sin->sin_family = AF_INET;
970 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
971 }
972 
973 /* Copy the primary address of the peer primary address as the msg_name. */
974 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
975 				    int *addr_len)
976 {
977 	struct sockaddr_in *sin, *sinfrom;
978 
979 	if (msgname) {
980 		struct sctp_association *asoc;
981 
982 		asoc = event->asoc;
983 		sctp_inet_msgname(msgname, addr_len);
984 		sin = (struct sockaddr_in *)msgname;
985 		sinfrom = &asoc->peer.primary_addr.v4;
986 		sin->sin_port = htons(asoc->peer.port);
987 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
988 	}
989 }
990 
991 /* Initialize and copy out a msgname from an inbound skb. */
992 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
993 {
994 	if (msgname) {
995 		struct sctphdr *sh = sctp_hdr(skb);
996 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
997 
998 		sctp_inet_msgname(msgname, len);
999 		sin->sin_port = sh->source;
1000 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1001 	}
1002 }
1003 
1004 /* Do we support this AF? */
1005 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
1006 {
1007 	/* PF_INET only supports AF_INET addresses. */
1008 	return AF_INET == family;
1009 }
1010 
1011 /* Address matching with wildcards allowed. */
1012 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
1013 			      const union sctp_addr *addr2,
1014 			      struct sctp_sock *opt)
1015 {
1016 	/* PF_INET only supports AF_INET addresses. */
1017 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1018 		return 0;
1019 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1020 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1021 		return 1;
1022 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1023 		return 1;
1024 
1025 	return 0;
1026 }
1027 
1028 /* Verify that provided sockaddr looks bindable.  Common verification has
1029  * already been taken care of.
1030  */
1031 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1032 {
1033 	return sctp_v4_available(addr, opt);
1034 }
1035 
1036 /* Verify that sockaddr looks sendable.  Common verification has already
1037  * been taken care of.
1038  */
1039 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1040 {
1041 	return 1;
1042 }
1043 
1044 /* Fill in Supported Address Type information for INIT and INIT-ACK
1045  * chunks.  Returns number of addresses supported.
1046  */
1047 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1048 				     __be16 *types)
1049 {
1050 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1051 	return 1;
1052 }
1053 
1054 /* Wrapper routine that calls the ip transmit routine. */
1055 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1056 {
1057 	struct dst_entry *dst = dst_clone(t->dst);
1058 	struct flowi4 *fl4 = &t->fl.u.ip4;
1059 	struct sock *sk = skb->sk;
1060 	struct inet_sock *inet = inet_sk(sk);
1061 	__u8 dscp = READ_ONCE(inet->tos);
1062 	__be16 df = 0;
1063 
1064 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1065 		 skb->len, &fl4->saddr, &fl4->daddr);
1066 
1067 	if (t->dscp & SCTP_DSCP_SET_MASK)
1068 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1069 
1070 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1071 							   : IP_PMTUDISC_DONT;
1072 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1073 
1074 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1075 		skb_dst_set(skb, dst);
1076 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1077 	}
1078 
1079 	if (skb_is_gso(skb))
1080 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1081 
1082 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1083 		df = htons(IP_DF);
1084 
1085 	skb->encapsulation = 1;
1086 	skb_reset_inner_mac_header(skb);
1087 	skb_reset_inner_transport_header(skb);
1088 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1089 	udp_tunnel_xmit_skb(dst_rtable(dst), sk, skb, fl4->saddr,
1090 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1091 			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
1092 	return 0;
1093 }
1094 
1095 static struct sctp_af sctp_af_inet;
1096 
1097 static struct sctp_pf sctp_pf_inet = {
1098 	.event_msgname = sctp_inet_event_msgname,
1099 	.skb_msgname   = sctp_inet_skb_msgname,
1100 	.af_supported  = sctp_inet_af_supported,
1101 	.cmp_addr      = sctp_inet_cmp_addr,
1102 	.bind_verify   = sctp_inet_bind_verify,
1103 	.send_verify   = sctp_inet_send_verify,
1104 	.supported_addrs = sctp_inet_supported_addrs,
1105 	.create_accept_sk = sctp_v4_create_accept_sk,
1106 	.addr_to_user  = sctp_v4_addr_to_user,
1107 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1108 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1109 	.copy_ip_options = sctp_v4_copy_ip_options,
1110 	.af            = &sctp_af_inet
1111 };
1112 
1113 /* Notifier for inetaddr addition/deletion events.  */
1114 static struct notifier_block sctp_inetaddr_notifier = {
1115 	.notifier_call = sctp_inetaddr_event,
1116 };
1117 
1118 /* Socket operations.  */
1119 static const struct proto_ops inet_seqpacket_ops = {
1120 	.family		   = PF_INET,
1121 	.owner		   = THIS_MODULE,
1122 	.release	   = inet_release,	/* Needs to be wrapped... */
1123 	.bind		   = inet_bind,
1124 	.connect	   = sctp_inet_connect,
1125 	.socketpair	   = sock_no_socketpair,
1126 	.accept		   = inet_accept,
1127 	.getname	   = inet_getname,	/* Semantics are different.  */
1128 	.poll		   = sctp_poll,
1129 	.ioctl		   = inet_ioctl,
1130 	.gettstamp	   = sock_gettstamp,
1131 	.listen		   = sctp_inet_listen,
1132 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1133 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1134 	.getsockopt	   = sock_common_getsockopt,
1135 	.sendmsg	   = inet_sendmsg,
1136 	.recvmsg	   = inet_recvmsg,
1137 	.mmap		   = sock_no_mmap,
1138 };
1139 
1140 /* Registration with AF_INET family.  */
1141 static struct inet_protosw sctp_seqpacket_protosw = {
1142 	.type       = SOCK_SEQPACKET,
1143 	.protocol   = IPPROTO_SCTP,
1144 	.prot       = &sctp_prot,
1145 	.ops        = &inet_seqpacket_ops,
1146 	.flags      = SCTP_PROTOSW_FLAG
1147 };
1148 static struct inet_protosw sctp_stream_protosw = {
1149 	.type       = SOCK_STREAM,
1150 	.protocol   = IPPROTO_SCTP,
1151 	.prot       = &sctp_prot,
1152 	.ops        = &inet_seqpacket_ops,
1153 	.flags      = SCTP_PROTOSW_FLAG
1154 };
1155 
1156 static int sctp4_rcv(struct sk_buff *skb)
1157 {
1158 	SCTP_INPUT_CB(skb)->encap_port = 0;
1159 	return sctp_rcv(skb);
1160 }
1161 
1162 /* Register with IP layer.  */
1163 static const struct net_protocol sctp_protocol = {
1164 	.handler     = sctp4_rcv,
1165 	.err_handler = sctp_v4_err,
1166 	.no_policy   = 1,
1167 	.icmp_strict_tag_validation = 1,
1168 };
1169 
1170 /* IPv4 address related functions.  */
1171 static struct sctp_af sctp_af_inet = {
1172 	.sa_family	   = AF_INET,
1173 	.sctp_xmit	   = sctp_v4_xmit,
1174 	.setsockopt	   = ip_setsockopt,
1175 	.getsockopt	   = ip_getsockopt,
1176 	.get_dst	   = sctp_v4_get_dst,
1177 	.get_saddr	   = sctp_v4_get_saddr,
1178 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1179 	.from_skb	   = sctp_v4_from_skb,
1180 	.from_sk	   = sctp_v4_from_sk,
1181 	.from_addr_param   = sctp_v4_from_addr_param,
1182 	.to_addr_param	   = sctp_v4_to_addr_param,
1183 	.cmp_addr	   = sctp_v4_cmp_addr,
1184 	.addr_valid	   = sctp_v4_addr_valid,
1185 	.inaddr_any	   = sctp_v4_inaddr_any,
1186 	.is_any		   = sctp_v4_is_any,
1187 	.available	   = sctp_v4_available,
1188 	.scope		   = sctp_v4_scope,
1189 	.skb_iif	   = sctp_v4_skb_iif,
1190 	.skb_sdif	   = sctp_v4_skb_sdif,
1191 	.is_ce		   = sctp_v4_is_ce,
1192 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1193 	.ecn_capable	   = sctp_v4_ecn_capable,
1194 	.net_header_len	   = sizeof(struct iphdr),
1195 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1196 	.ip_options_len	   = sctp_v4_ip_options_len,
1197 };
1198 
1199 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1200 {
1201 	switch (family) {
1202 	case PF_INET:
1203 		return sctp_pf_inet_specific;
1204 	case PF_INET6:
1205 		return sctp_pf_inet6_specific;
1206 	default:
1207 		return NULL;
1208 	}
1209 }
1210 
1211 /* Register the PF specific function table.  */
1212 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1213 {
1214 	switch (family) {
1215 	case PF_INET:
1216 		if (sctp_pf_inet_specific)
1217 			return 0;
1218 		sctp_pf_inet_specific = pf;
1219 		break;
1220 	case PF_INET6:
1221 		if (sctp_pf_inet6_specific)
1222 			return 0;
1223 		sctp_pf_inet6_specific = pf;
1224 		break;
1225 	default:
1226 		return 0;
1227 	}
1228 	return 1;
1229 }
1230 
1231 static inline int init_sctp_mibs(struct net *net)
1232 {
1233 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1234 	if (!net->sctp.sctp_statistics)
1235 		return -ENOMEM;
1236 	return 0;
1237 }
1238 
1239 static inline void cleanup_sctp_mibs(struct net *net)
1240 {
1241 	free_percpu(net->sctp.sctp_statistics);
1242 }
1243 
1244 static void sctp_v4_pf_init(void)
1245 {
1246 	/* Initialize the SCTP specific PF functions. */
1247 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1248 	sctp_register_af(&sctp_af_inet);
1249 }
1250 
1251 static void sctp_v4_pf_exit(void)
1252 {
1253 	list_del(&sctp_af_inet.list);
1254 }
1255 
1256 static int sctp_v4_protosw_init(void)
1257 {
1258 	int rc;
1259 
1260 	rc = proto_register(&sctp_prot, 1);
1261 	if (rc)
1262 		return rc;
1263 
1264 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1265 	inet_register_protosw(&sctp_seqpacket_protosw);
1266 	inet_register_protosw(&sctp_stream_protosw);
1267 
1268 	return 0;
1269 }
1270 
1271 static void sctp_v4_protosw_exit(void)
1272 {
1273 	inet_unregister_protosw(&sctp_stream_protosw);
1274 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1275 	proto_unregister(&sctp_prot);
1276 }
1277 
1278 static int sctp_v4_add_protocol(void)
1279 {
1280 	/* Register notifier for inet address additions/deletions. */
1281 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1282 
1283 	/* Register SCTP with inet layer.  */
1284 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1285 		return -EAGAIN;
1286 
1287 	return 0;
1288 }
1289 
1290 static void sctp_v4_del_protocol(void)
1291 {
1292 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1293 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1294 }
1295 
1296 static int __net_init sctp_defaults_init(struct net *net)
1297 {
1298 	int status;
1299 
1300 	/*
1301 	 * 14. Suggested SCTP Protocol Parameter Values
1302 	 */
1303 	/* The following protocol parameters are RECOMMENDED:  */
1304 	/* RTO.Initial              - 3  seconds */
1305 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1306 	/* RTO.Min                  - 1  second */
1307 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1308 	/* RTO.Max                 -  60 seconds */
1309 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1310 	/* RTO.Alpha                - 1/8 */
1311 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1312 	/* RTO.Beta                 - 1/4 */
1313 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1314 
1315 	/* Valid.Cookie.Life        - 60  seconds */
1316 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1317 
1318 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1319 	net->sctp.cookie_preserve_enable 	= 1;
1320 
1321 	/* Default sctp sockets to use md5 as their hmac alg */
1322 #if defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5)
1323 	net->sctp.sctp_hmac_alg			= "md5";
1324 #elif defined (CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1)
1325 	net->sctp.sctp_hmac_alg			= "sha1";
1326 #else
1327 	net->sctp.sctp_hmac_alg			= NULL;
1328 #endif
1329 
1330 	/* Max.Burst		    - 4 */
1331 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1332 
1333 	/* Disable of Primary Path Switchover by default */
1334 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1335 
1336 	/* Enable pf state by default */
1337 	net->sctp.pf_enable = 1;
1338 
1339 	/* Ignore pf exposure feature by default */
1340 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1341 
1342 	/* Association.Max.Retrans  - 10 attempts
1343 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1344 	 * Max.Init.Retransmits     - 8  attempts
1345 	 */
1346 	net->sctp.max_retrans_association	= 10;
1347 	net->sctp.max_retrans_path		= 5;
1348 	net->sctp.max_retrans_init		= 8;
1349 
1350 	/* Sendbuffer growth	    - do per-socket accounting */
1351 	net->sctp.sndbuf_policy			= 0;
1352 
1353 	/* Rcvbuffer growth	    - do per-socket accounting */
1354 	net->sctp.rcvbuf_policy			= 0;
1355 
1356 	/* HB.interval              - 30 seconds */
1357 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1358 
1359 	/* delayed SACK timeout */
1360 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1361 
1362 	/* Disable ADDIP by default. */
1363 	net->sctp.addip_enable = 0;
1364 	net->sctp.addip_noauth = 0;
1365 	net->sctp.default_auto_asconf = 0;
1366 
1367 	/* Enable PR-SCTP by default. */
1368 	net->sctp.prsctp_enable = 1;
1369 
1370 	/* Disable RECONF by default. */
1371 	net->sctp.reconf_enable = 0;
1372 
1373 	/* Disable AUTH by default. */
1374 	net->sctp.auth_enable = 0;
1375 
1376 	/* Enable ECN by default. */
1377 	net->sctp.ecn_enable = 1;
1378 
1379 	/* Set UDP tunneling listening port to 0 by default */
1380 	net->sctp.udp_port = 0;
1381 
1382 	/* Set remote encap port to 0 by default */
1383 	net->sctp.encap_port = 0;
1384 
1385 	/* Set SCOPE policy to enabled */
1386 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1387 
1388 	/* Set the default rwnd update threshold */
1389 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1390 
1391 	/* Initialize maximum autoclose timeout. */
1392 	net->sctp.max_autoclose		= INT_MAX / HZ;
1393 
1394 #ifdef CONFIG_NET_L3_MASTER_DEV
1395 	net->sctp.l3mdev_accept = 1;
1396 #endif
1397 
1398 	status = sctp_sysctl_net_register(net);
1399 	if (status)
1400 		goto err_sysctl_register;
1401 
1402 	/* Allocate and initialise sctp mibs.  */
1403 	status = init_sctp_mibs(net);
1404 	if (status)
1405 		goto err_init_mibs;
1406 
1407 #ifdef CONFIG_PROC_FS
1408 	/* Initialize proc fs directory.  */
1409 	status = sctp_proc_init(net);
1410 	if (status)
1411 		goto err_init_proc;
1412 #endif
1413 
1414 	sctp_dbg_objcnt_init(net);
1415 
1416 	/* Initialize the local address list. */
1417 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1418 	spin_lock_init(&net->sctp.local_addr_lock);
1419 	sctp_get_local_addr_list(net);
1420 
1421 	/* Initialize the address event list */
1422 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1423 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1424 	spin_lock_init(&net->sctp.addr_wq_lock);
1425 	net->sctp.addr_wq_timer.expires = 0;
1426 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1427 
1428 	return 0;
1429 
1430 #ifdef CONFIG_PROC_FS
1431 err_init_proc:
1432 	cleanup_sctp_mibs(net);
1433 #endif
1434 err_init_mibs:
1435 	sctp_sysctl_net_unregister(net);
1436 err_sysctl_register:
1437 	return status;
1438 }
1439 
1440 static void __net_exit sctp_defaults_exit(struct net *net)
1441 {
1442 	/* Free the local address list */
1443 	sctp_free_addr_wq(net);
1444 	sctp_free_local_addr_list(net);
1445 
1446 #ifdef CONFIG_PROC_FS
1447 	remove_proc_subtree("sctp", net->proc_net);
1448 	net->sctp.proc_net_sctp = NULL;
1449 #endif
1450 	cleanup_sctp_mibs(net);
1451 	sctp_sysctl_net_unregister(net);
1452 }
1453 
1454 static struct pernet_operations sctp_defaults_ops = {
1455 	.init = sctp_defaults_init,
1456 	.exit = sctp_defaults_exit,
1457 };
1458 
1459 static int __net_init sctp_ctrlsock_init(struct net *net)
1460 {
1461 	int status;
1462 
1463 	/* Initialize the control inode/socket for handling OOTB packets.  */
1464 	status = sctp_ctl_sock_init(net);
1465 	if (status)
1466 		pr_err("Failed to initialize the SCTP control sock\n");
1467 
1468 	return status;
1469 }
1470 
1471 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1472 {
1473 	/* Free the control endpoint.  */
1474 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1475 }
1476 
1477 static struct pernet_operations sctp_ctrlsock_ops = {
1478 	.init = sctp_ctrlsock_init,
1479 	.exit = sctp_ctrlsock_exit,
1480 };
1481 
1482 /* Initialize the universe into something sensible.  */
1483 static __init int sctp_init(void)
1484 {
1485 	unsigned long nr_pages = totalram_pages();
1486 	unsigned long limit;
1487 	unsigned long goal;
1488 	int max_entry_order;
1489 	int num_entries;
1490 	int max_share;
1491 	int status;
1492 	int order;
1493 	int i;
1494 
1495 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1496 
1497 	/* Allocate bind_bucket and chunk caches. */
1498 	status = -ENOBUFS;
1499 	sctp_bucket_cachep = KMEM_CACHE(sctp_bind_bucket, SLAB_HWCACHE_ALIGN);
1500 	if (!sctp_bucket_cachep)
1501 		goto out;
1502 
1503 	sctp_chunk_cachep = KMEM_CACHE(sctp_chunk, SLAB_HWCACHE_ALIGN);
1504 	if (!sctp_chunk_cachep)
1505 		goto err_chunk_cachep;
1506 
1507 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1508 	if (status)
1509 		goto err_percpu_counter_init;
1510 
1511 	/* Implementation specific variables. */
1512 
1513 	/* Initialize default stream count setup information. */
1514 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1515 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1516 
1517 	/* Initialize handle used for association ids. */
1518 	idr_init(&sctp_assocs_id);
1519 
1520 	limit = nr_free_buffer_pages() / 8;
1521 	limit = max(limit, 128UL);
1522 	sysctl_sctp_mem[0] = limit / 4 * 3;
1523 	sysctl_sctp_mem[1] = limit;
1524 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1525 
1526 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1527 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1528 	max_share = min(4UL*1024*1024, limit);
1529 
1530 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1531 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1532 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1533 
1534 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1535 	sysctl_sctp_wmem[1] = 16*1024;
1536 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1537 
1538 	/* Size and allocate the association hash table.
1539 	 * The methodology is similar to that of the tcp hash tables.
1540 	 * Though not identical.  Start by getting a goal size
1541 	 */
1542 	if (nr_pages >= (128 * 1024))
1543 		goal = nr_pages >> (22 - PAGE_SHIFT);
1544 	else
1545 		goal = nr_pages >> (24 - PAGE_SHIFT);
1546 
1547 	/* Then compute the page order for said goal */
1548 	order = get_order(goal);
1549 
1550 	/* Now compute the required page order for the maximum sized table we
1551 	 * want to create
1552 	 */
1553 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1554 				    sizeof(struct sctp_bind_hashbucket));
1555 
1556 	/* Limit the page order by that maximum hash table size */
1557 	order = min(order, max_entry_order);
1558 
1559 	/* Allocate and initialize the endpoint hash table.  */
1560 	sctp_ep_hashsize = 64;
1561 	sctp_ep_hashtable =
1562 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1563 	if (!sctp_ep_hashtable) {
1564 		pr_err("Failed endpoint_hash alloc\n");
1565 		status = -ENOMEM;
1566 		goto err_ehash_alloc;
1567 	}
1568 	for (i = 0; i < sctp_ep_hashsize; i++) {
1569 		rwlock_init(&sctp_ep_hashtable[i].lock);
1570 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1571 	}
1572 
1573 	/* Allocate and initialize the SCTP port hash table.
1574 	 * Note that order is initalized to start at the max sized
1575 	 * table we want to support.  If we can't get that many pages
1576 	 * reduce the order and try again
1577 	 */
1578 	do {
1579 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1580 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1581 	} while (!sctp_port_hashtable && --order > 0);
1582 
1583 	if (!sctp_port_hashtable) {
1584 		pr_err("Failed bind hash alloc\n");
1585 		status = -ENOMEM;
1586 		goto err_bhash_alloc;
1587 	}
1588 
1589 	/* Now compute the number of entries that will fit in the
1590 	 * port hash space we allocated
1591 	 */
1592 	num_entries = (1UL << order) * PAGE_SIZE /
1593 		      sizeof(struct sctp_bind_hashbucket);
1594 
1595 	/* And finish by rounding it down to the nearest power of two.
1596 	 * This wastes some memory of course, but it's needed because
1597 	 * the hash function operates based on the assumption that
1598 	 * the number of entries is a power of two.
1599 	 */
1600 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1601 
1602 	for (i = 0; i < sctp_port_hashsize; i++) {
1603 		spin_lock_init(&sctp_port_hashtable[i].lock);
1604 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1605 	}
1606 
1607 	status = sctp_transport_hashtable_init();
1608 	if (status)
1609 		goto err_thash_alloc;
1610 
1611 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1612 		num_entries);
1613 
1614 	sctp_sysctl_register();
1615 
1616 	INIT_LIST_HEAD(&sctp_address_families);
1617 	sctp_v4_pf_init();
1618 	sctp_v6_pf_init();
1619 	sctp_sched_ops_init();
1620 
1621 	status = register_pernet_subsys(&sctp_defaults_ops);
1622 	if (status)
1623 		goto err_register_defaults;
1624 
1625 	status = sctp_v4_protosw_init();
1626 	if (status)
1627 		goto err_protosw_init;
1628 
1629 	status = sctp_v6_protosw_init();
1630 	if (status)
1631 		goto err_v6_protosw_init;
1632 
1633 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1634 	if (status)
1635 		goto err_register_ctrlsock;
1636 
1637 	status = sctp_v4_add_protocol();
1638 	if (status)
1639 		goto err_add_protocol;
1640 
1641 	/* Register SCTP with inet6 layer.  */
1642 	status = sctp_v6_add_protocol();
1643 	if (status)
1644 		goto err_v6_add_protocol;
1645 
1646 	if (sctp_offload_init() < 0)
1647 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1648 
1649 out:
1650 	return status;
1651 err_v6_add_protocol:
1652 	sctp_v4_del_protocol();
1653 err_add_protocol:
1654 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1655 err_register_ctrlsock:
1656 	sctp_v6_protosw_exit();
1657 err_v6_protosw_init:
1658 	sctp_v4_protosw_exit();
1659 err_protosw_init:
1660 	unregister_pernet_subsys(&sctp_defaults_ops);
1661 err_register_defaults:
1662 	sctp_v4_pf_exit();
1663 	sctp_v6_pf_exit();
1664 	sctp_sysctl_unregister();
1665 	free_pages((unsigned long)sctp_port_hashtable,
1666 		   get_order(sctp_port_hashsize *
1667 			     sizeof(struct sctp_bind_hashbucket)));
1668 err_bhash_alloc:
1669 	sctp_transport_hashtable_destroy();
1670 err_thash_alloc:
1671 	kfree(sctp_ep_hashtable);
1672 err_ehash_alloc:
1673 	percpu_counter_destroy(&sctp_sockets_allocated);
1674 err_percpu_counter_init:
1675 	kmem_cache_destroy(sctp_chunk_cachep);
1676 err_chunk_cachep:
1677 	kmem_cache_destroy(sctp_bucket_cachep);
1678 	goto out;
1679 }
1680 
1681 /* Exit handler for the SCTP protocol.  */
1682 static __exit void sctp_exit(void)
1683 {
1684 	/* BUG.  This should probably do something useful like clean
1685 	 * up all the remaining associations and all that memory.
1686 	 */
1687 
1688 	/* Unregister with inet6/inet layers. */
1689 	sctp_v6_del_protocol();
1690 	sctp_v4_del_protocol();
1691 
1692 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1693 
1694 	/* Free protosw registrations */
1695 	sctp_v6_protosw_exit();
1696 	sctp_v4_protosw_exit();
1697 
1698 	unregister_pernet_subsys(&sctp_defaults_ops);
1699 
1700 	/* Unregister with socket layer. */
1701 	sctp_v6_pf_exit();
1702 	sctp_v4_pf_exit();
1703 
1704 	sctp_sysctl_unregister();
1705 
1706 	free_pages((unsigned long)sctp_port_hashtable,
1707 		   get_order(sctp_port_hashsize *
1708 			     sizeof(struct sctp_bind_hashbucket)));
1709 	kfree(sctp_ep_hashtable);
1710 	sctp_transport_hashtable_destroy();
1711 
1712 	percpu_counter_destroy(&sctp_sockets_allocated);
1713 
1714 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1715 
1716 	kmem_cache_destroy(sctp_chunk_cachep);
1717 	kmem_cache_destroy(sctp_bucket_cachep);
1718 }
1719 
1720 module_init(sctp_init);
1721 module_exit(sctp_exit);
1722 
1723 /*
1724  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1725  */
1726 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1727 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1728 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1729 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1730 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1731 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1732 MODULE_LICENSE("GPL");
1733