xref: /linux/net/sctp/protocol.c (revision 6dfafbd0299a60bfb5d5e277fdf100037c7ded07)
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/flow.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/inet_sock.h>
48 #include <net/udp_tunnel.h>
49 #include <net/inet_dscp.h>
50 
51 #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024)
52 
53 /* Global data structures. */
54 struct sctp_globals sctp_globals __read_mostly;
55 
56 struct idr sctp_assocs_id;
57 DEFINE_SPINLOCK(sctp_assocs_id_lock);
58 
59 static struct sctp_pf *sctp_pf_inet6_specific;
60 static struct sctp_pf *sctp_pf_inet_specific;
61 static struct sctp_af *sctp_af_v4_specific;
62 static struct sctp_af *sctp_af_v6_specific;
63 
64 struct kmem_cache *sctp_chunk_cachep __read_mostly;
65 struct kmem_cache *sctp_bucket_cachep __read_mostly;
66 
67 long sysctl_sctp_mem[3];
68 int sysctl_sctp_rmem[3];
69 int sysctl_sctp_wmem[3];
70 
71 /* Private helper to extract ipv4 address and stash them in
72  * the protocol structure.
73  */
74 static void sctp_v4_copy_addrlist(struct list_head *addrlist,
75 				  struct net_device *dev)
76 {
77 	struct in_device *in_dev;
78 	struct in_ifaddr *ifa;
79 	struct sctp_sockaddr_entry *addr;
80 
81 	rcu_read_lock();
82 	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
83 		rcu_read_unlock();
84 		return;
85 	}
86 
87 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
88 		/* Add the address to the local list.  */
89 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
90 		if (addr) {
91 			addr->a.v4.sin_family = AF_INET;
92 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
93 			addr->valid = 1;
94 			INIT_LIST_HEAD(&addr->list);
95 			list_add_tail(&addr->list, addrlist);
96 		}
97 	}
98 
99 	rcu_read_unlock();
100 }
101 
102 /* Extract our IP addresses from the system and stash them in the
103  * protocol structure.
104  */
105 static void sctp_get_local_addr_list(struct net *net)
106 {
107 	struct net_device *dev;
108 	struct list_head *pos;
109 	struct sctp_af *af;
110 
111 	rcu_read_lock();
112 	for_each_netdev_rcu(net, dev) {
113 		list_for_each(pos, &sctp_address_families) {
114 			af = list_entry(pos, struct sctp_af, list);
115 			af->copy_addrlist(&net->sctp.local_addr_list, dev);
116 		}
117 	}
118 	rcu_read_unlock();
119 }
120 
121 /* Free the existing local addresses.  */
122 static void sctp_free_local_addr_list(struct net *net)
123 {
124 	struct sctp_sockaddr_entry *addr;
125 	struct list_head *pos, *temp;
126 
127 	list_for_each_safe(pos, temp, &net->sctp.local_addr_list) {
128 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
129 		list_del(pos);
130 		kfree(addr);
131 	}
132 }
133 
134 /* Copy the local addresses which are valid for 'scope' into 'bp'.  */
135 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
136 			      enum sctp_scope scope, gfp_t gfp, int copy_flags)
137 {
138 	struct sctp_sockaddr_entry *addr;
139 	union sctp_addr laddr;
140 	int error = 0;
141 
142 	rcu_read_lock();
143 	list_for_each_entry_rcu(addr, &net->sctp.local_addr_list, list) {
144 		if (!addr->valid)
145 			continue;
146 		if (!sctp_in_scope(net, &addr->a, scope))
147 			continue;
148 
149 		/* Now that the address is in scope, check to see if
150 		 * the address type is really supported by the local
151 		 * sock as well as the remote peer.
152 		 */
153 		if (addr->a.sa.sa_family == AF_INET &&
154 		    (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
155 		     !(copy_flags & SCTP_ADDR4_PEERSUPP)))
156 			continue;
157 		if (addr->a.sa.sa_family == AF_INET6 &&
158 		    (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
159 		     !(copy_flags & SCTP_ADDR6_PEERSUPP)))
160 			continue;
161 
162 		laddr = addr->a;
163 		/* also works for setting ipv6 address port */
164 		laddr.v4.sin_port = htons(bp->port);
165 		if (sctp_bind_addr_state(bp, &laddr) != -1)
166 			continue;
167 
168 		error = sctp_add_bind_addr(bp, &addr->a, sizeof(addr->a),
169 					   SCTP_ADDR_SRC, GFP_ATOMIC);
170 		if (error)
171 			break;
172 	}
173 
174 	rcu_read_unlock();
175 	return error;
176 }
177 
178 /* Copy over any ip options */
179 static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
180 {
181 	struct inet_sock *newinet, *inet = inet_sk(sk);
182 	struct ip_options_rcu *inet_opt, *newopt = NULL;
183 
184 	newinet = inet_sk(newsk);
185 
186 	rcu_read_lock();
187 	inet_opt = rcu_dereference(inet->inet_opt);
188 	if (inet_opt) {
189 		newopt = sock_kmemdup(newsk, inet_opt, sizeof(*inet_opt) +
190 				      inet_opt->opt.optlen, GFP_ATOMIC);
191 		if (!newopt)
192 			pr_err("%s: Failed to copy ip options\n", __func__);
193 	}
194 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
195 	rcu_read_unlock();
196 }
197 
198 /* Account for the IP options */
199 static int sctp_v4_ip_options_len(struct sock *sk)
200 {
201 	struct inet_sock *inet = inet_sk(sk);
202 	struct ip_options_rcu *inet_opt;
203 	int len = 0;
204 
205 	rcu_read_lock();
206 	inet_opt = rcu_dereference(inet->inet_opt);
207 	if (inet_opt)
208 		len = inet_opt->opt.optlen;
209 
210 	rcu_read_unlock();
211 	return len;
212 }
213 
214 /* Initialize a sctp_addr from in incoming skb.  */
215 static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
216 			     int is_saddr)
217 {
218 	/* Always called on head skb, so this is safe */
219 	struct sctphdr *sh = sctp_hdr(skb);
220 	struct sockaddr_in *sa = &addr->v4;
221 
222 	addr->v4.sin_family = AF_INET;
223 
224 	if (is_saddr) {
225 		sa->sin_port = sh->source;
226 		sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
227 	} else {
228 		sa->sin_port = sh->dest;
229 		sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
230 	}
231 	memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
232 }
233 
234 /* Initialize an sctp_addr from a socket. */
235 static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
236 {
237 	addr->v4.sin_family = AF_INET;
238 	addr->v4.sin_port = 0;
239 	addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
240 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
241 }
242 
243 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
244 static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
245 {
246 	inet_sk(sk)->inet_rcv_saddr = addr->v4.sin_addr.s_addr;
247 }
248 
249 /* Initialize sk->sk_daddr from sctp_addr. */
250 static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
251 {
252 	inet_sk(sk)->inet_daddr = addr->v4.sin_addr.s_addr;
253 }
254 
255 /* Initialize a sctp_addr from an address parameter. */
256 static bool sctp_v4_from_addr_param(union sctp_addr *addr,
257 				    union sctp_addr_param *param,
258 				    __be16 port, int iif)
259 {
260 	if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
261 		return false;
262 
263 	addr->v4.sin_family = AF_INET;
264 	addr->v4.sin_port = port;
265 	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
266 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
267 
268 	return true;
269 }
270 
271 /* Initialize an address parameter from a sctp_addr and return the length
272  * of the address parameter.
273  */
274 static int sctp_v4_to_addr_param(const union sctp_addr *addr,
275 				 union sctp_addr_param *param)
276 {
277 	int length = sizeof(struct sctp_ipv4addr_param);
278 
279 	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
280 	param->v4.param_hdr.length = htons(length);
281 	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;
282 
283 	return length;
284 }
285 
286 /* Initialize a sctp_addr from a dst_entry. */
287 static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct flowi4 *fl4,
288 			      __be16 port)
289 {
290 	saddr->v4.sin_family = AF_INET;
291 	saddr->v4.sin_port = port;
292 	saddr->v4.sin_addr.s_addr = fl4->saddr;
293 	memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
294 }
295 
296 /* Compare two addresses exactly. */
297 static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
298 			    const union sctp_addr *addr2)
299 {
300 	if (addr1->sa.sa_family != addr2->sa.sa_family)
301 		return 0;
302 	if (addr1->v4.sin_port != addr2->v4.sin_port)
303 		return 0;
304 	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
305 		return 0;
306 
307 	return 1;
308 }
309 
310 /* Initialize addr struct to INADDR_ANY. */
311 static void sctp_v4_inaddr_any(union sctp_addr *addr, __be16 port)
312 {
313 	addr->v4.sin_family = AF_INET;
314 	addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
315 	addr->v4.sin_port = port;
316 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
317 }
318 
319 /* Is this a wildcard address? */
320 static int sctp_v4_is_any(const union sctp_addr *addr)
321 {
322 	return htonl(INADDR_ANY) == addr->v4.sin_addr.s_addr;
323 }
324 
325 /* This function checks if the address is a valid address to be used for
326  * SCTP binding.
327  *
328  * Output:
329  * Return 0 - If the address is a non-unicast or an illegal address.
330  * Return 1 - If the address is a unicast.
331  */
332 static int sctp_v4_addr_valid(union sctp_addr *addr,
333 			      struct sctp_sock *sp,
334 			      const struct sk_buff *skb)
335 {
336 	/* IPv4 addresses not allowed */
337 	if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
338 		return 0;
339 
340 	/* Is this a non-unicast address or a unusable SCTP address? */
341 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr))
342 		return 0;
343 
344 	/* Is this a broadcast address? */
345 	if (skb && skb_rtable(skb)->rt_flags & RTCF_BROADCAST)
346 		return 0;
347 
348 	return 1;
349 }
350 
351 /* Should this be available for binding?   */
352 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
353 {
354 	struct sock *sk = &sp->inet.sk;
355 	struct net *net = sock_net(sk);
356 	int tb_id = RT_TABLE_LOCAL;
357 	int ret;
358 
359 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
360 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
361 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
362 	   ret != RTN_LOCAL &&
363 	   !inet_test_bit(FREEBIND, sk) &&
364 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
365 		return 0;
366 
367 	if (ipv6_only_sock(sctp_opt2sk(sp)))
368 		return 0;
369 
370 	return 1;
371 }
372 
373 /* Checking the loopback, private and other address scopes as defined in
374  * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
375  * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
376  *
377  * Level 0 - unusable SCTP addresses
378  * Level 1 - loopback address
379  * Level 2 - link-local addresses
380  * Level 3 - private addresses.
381  * Level 4 - global addresses
382  * For INIT and INIT-ACK address list, let L be the level of
383  * requested destination address, sender and receiver
384  * SHOULD include all of its addresses with level greater
385  * than or equal to L.
386  *
387  * IPv4 scoping can be controlled through sysctl option
388  * net.sctp.addr_scope_policy
389  */
390 static enum sctp_scope sctp_v4_scope(union sctp_addr *addr)
391 {
392 	enum sctp_scope retval;
393 
394 	/* Check for unusable SCTP addresses. */
395 	if (IS_IPV4_UNUSABLE_ADDRESS(addr->v4.sin_addr.s_addr)) {
396 		retval =  SCTP_SCOPE_UNUSABLE;
397 	} else if (ipv4_is_loopback(addr->v4.sin_addr.s_addr)) {
398 		retval = SCTP_SCOPE_LOOPBACK;
399 	} else if (ipv4_is_linklocal_169(addr->v4.sin_addr.s_addr)) {
400 		retval = SCTP_SCOPE_LINK;
401 	} else if (ipv4_is_private_10(addr->v4.sin_addr.s_addr) ||
402 		   ipv4_is_private_172(addr->v4.sin_addr.s_addr) ||
403 		   ipv4_is_private_192(addr->v4.sin_addr.s_addr) ||
404 		   ipv4_is_test_198(addr->v4.sin_addr.s_addr)) {
405 		retval = SCTP_SCOPE_PRIVATE;
406 	} else {
407 		retval = SCTP_SCOPE_GLOBAL;
408 	}
409 
410 	return retval;
411 }
412 
413 /* Returns a valid dst cache entry for the given source and destination ip
414  * addresses. If an association is passed, trys to get a dst entry with a
415  * source address that matches an address in the bind address list.
416  */
417 static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
418 				struct flowi *fl, struct sock *sk)
419 {
420 	struct sctp_association *asoc = t->asoc;
421 	struct rtable *rt;
422 	struct flowi _fl;
423 	struct flowi4 *fl4 = &_fl.u.ip4;
424 	struct sctp_bind_addr *bp;
425 	struct sctp_sockaddr_entry *laddr;
426 	struct dst_entry *dst = NULL;
427 	union sctp_addr *daddr = &t->ipaddr;
428 	union sctp_addr dst_saddr;
429 	dscp_t dscp;
430 
431 	if (t->dscp & SCTP_DSCP_SET_MASK)
432 		dscp = inet_dsfield_to_dscp(t->dscp);
433 	else
434 		dscp = inet_sk_dscp(inet_sk(sk));
435 
436 	memset(&_fl, 0x0, sizeof(_fl));
437 	fl4->daddr  = daddr->v4.sin_addr.s_addr;
438 	fl4->fl4_dport = daddr->v4.sin_port;
439 	fl4->flowi4_proto = IPPROTO_SCTP;
440 	if (asoc) {
441 		fl4->flowi4_dscp = dscp;
442 		fl4->flowi4_scope = ip_sock_rt_scope(asoc->base.sk);
443 		fl4->flowi4_oif = asoc->base.sk->sk_bound_dev_if;
444 		fl4->fl4_sport = htons(asoc->base.bind_addr.port);
445 	}
446 	if (saddr) {
447 		fl4->saddr = saddr->v4.sin_addr.s_addr;
448 		if (!fl4->fl4_sport)
449 			fl4->fl4_sport = saddr->v4.sin_port;
450 	}
451 
452 	pr_debug("%s: dst:%pI4, src:%pI4 - ", __func__, &fl4->daddr,
453 		 &fl4->saddr);
454 
455 	rt = ip_route_output_key(sock_net(sk), fl4);
456 	if (!IS_ERR(rt)) {
457 		dst = &rt->dst;
458 		t->dst = dst;
459 		memcpy(fl, &_fl, sizeof(_fl));
460 	}
461 
462 	/* If there is no association or if a source address is passed, no
463 	 * more validation is required.
464 	 */
465 	if (!asoc || saddr)
466 		goto out;
467 
468 	bp = &asoc->base.bind_addr;
469 
470 	if (dst) {
471 		/* Walk through the bind address list and look for a bind
472 		 * address that matches the source address of the returned dst.
473 		 */
474 		sctp_v4_dst_saddr(&dst_saddr, fl4, htons(bp->port));
475 		rcu_read_lock();
476 		list_for_each_entry_rcu(laddr, &bp->address_list, list) {
477 			if (!laddr->valid || (laddr->state == SCTP_ADDR_DEL) ||
478 			    (laddr->state != SCTP_ADDR_SRC &&
479 			    !asoc->src_out_of_asoc_ok))
480 				continue;
481 			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
482 				goto out_unlock;
483 		}
484 		rcu_read_unlock();
485 
486 		/* None of the bound addresses match the source address of the
487 		 * dst. So release it.
488 		 */
489 		dst_release(dst);
490 		dst = NULL;
491 	}
492 
493 	/* Walk through the bind address list and try to get a dst that
494 	 * matches a bind address as the source address.
495 	 */
496 	rcu_read_lock();
497 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
498 		struct net_device *odev;
499 
500 		if (!laddr->valid)
501 			continue;
502 		if (laddr->state != SCTP_ADDR_SRC ||
503 		    AF_INET != laddr->a.sa.sa_family)
504 			continue;
505 
506 		fl4->fl4_sport = laddr->a.v4.sin_port;
507 		flowi4_update_output(fl4, asoc->base.sk->sk_bound_dev_if,
508 				     daddr->v4.sin_addr.s_addr,
509 				     laddr->a.v4.sin_addr.s_addr);
510 
511 		rt = ip_route_output_key(sock_net(sk), fl4);
512 		if (IS_ERR(rt))
513 			continue;
514 
515 		/* Ensure the src address belongs to the output
516 		 * interface.
517 		 */
518 		odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr,
519 				     false);
520 		if (!odev || odev->ifindex != fl4->flowi4_oif) {
521 			if (!dst) {
522 				dst = &rt->dst;
523 				t->dst = dst;
524 				memcpy(fl, &_fl, sizeof(_fl));
525 			} else {
526 				dst_release(&rt->dst);
527 			}
528 			continue;
529 		}
530 
531 		dst_release(dst);
532 		dst = &rt->dst;
533 		t->dst = dst;
534 		memcpy(fl, &_fl, sizeof(_fl));
535 		break;
536 	}
537 
538 out_unlock:
539 	rcu_read_unlock();
540 out:
541 	if (dst) {
542 		pr_debug("rt_dst:%pI4, rt_src:%pI4\n",
543 			 &fl->u.ip4.daddr, &fl->u.ip4.saddr);
544 	} else {
545 		t->dst = NULL;
546 		pr_debug("no route\n");
547 	}
548 }
549 
550 /* For v4, the source address is cached in the route entry(dst). So no need
551  * to cache it separately and hence this is an empty routine.
552  */
553 static void sctp_v4_get_saddr(struct sctp_sock *sk,
554 			      struct sctp_transport *t,
555 			      struct flowi *fl)
556 {
557 	union sctp_addr *saddr = &t->saddr;
558 	struct rtable *rt = dst_rtable(t->dst);
559 
560 	if (rt) {
561 		saddr->v4.sin_family = AF_INET;
562 		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
563 	}
564 }
565 
566 /* What interface did this skb arrive on? */
567 static int sctp_v4_skb_iif(const struct sk_buff *skb)
568 {
569 	return inet_iif(skb);
570 }
571 
572 static int sctp_v4_skb_sdif(const struct sk_buff *skb)
573 {
574 	return inet_sdif(skb);
575 }
576 
577 /* Was this packet marked by Explicit Congestion Notification? */
578 static int sctp_v4_is_ce(const struct sk_buff *skb)
579 {
580 	return INET_ECN_is_ce(ip_hdr(skb)->tos);
581 }
582 
583 static int sctp_v4_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
584 {
585 	/* No address mapping for V4 sockets */
586 	memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
587 	return sizeof(struct sockaddr_in);
588 }
589 
590 /* Dump the v4 addr to the seq file. */
591 static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
592 {
593 	seq_printf(seq, "%pI4 ", &addr->v4.sin_addr);
594 }
595 
596 static void sctp_v4_ecn_capable(struct sock *sk)
597 {
598 	INET_ECN_xmit(sk);
599 }
600 
601 static void sctp_addr_wq_timeout_handler(struct timer_list *t)
602 {
603 	struct net *net = timer_container_of(net, t, sctp.addr_wq_timer);
604 	struct sctp_sockaddr_entry *addrw, *temp;
605 	struct sctp_sock *sp;
606 
607 	spin_lock_bh(&net->sctp.addr_wq_lock);
608 
609 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
610 		pr_debug("%s: the first ent in wq:%p is addr:%pISc for cmd:%d at "
611 			 "entry:%p\n", __func__, &net->sctp.addr_waitq, &addrw->a.sa,
612 			 addrw->state, addrw);
613 
614 #if IS_ENABLED(CONFIG_IPV6)
615 		/* Now we send an ASCONF for each association */
616 		/* Note. we currently don't handle link local IPv6 addressees */
617 		if (addrw->a.sa.sa_family == AF_INET6) {
618 			struct in6_addr *in6;
619 
620 			if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
621 			    IPV6_ADDR_LINKLOCAL)
622 				goto free_next;
623 
624 			in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
625 			if (ipv6_chk_addr(net, in6, NULL, 0) == 0 &&
626 			    addrw->state == SCTP_ADDR_NEW) {
627 				unsigned long timeo_val;
628 
629 				pr_debug("%s: this is on DAD, trying %d sec "
630 					 "later\n", __func__,
631 					 SCTP_ADDRESS_TICK_DELAY);
632 
633 				timeo_val = jiffies;
634 				timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
635 				mod_timer(&net->sctp.addr_wq_timer, timeo_val);
636 				break;
637 			}
638 		}
639 #endif
640 		list_for_each_entry(sp, &net->sctp.auto_asconf_splist, auto_asconf_list) {
641 			struct sock *sk;
642 
643 			sk = sctp_opt2sk(sp);
644 			/* ignore bound-specific endpoints */
645 			if (!sctp_is_ep_boundall(sk))
646 				continue;
647 			bh_lock_sock(sk);
648 			if (sctp_asconf_mgmt(sp, addrw) < 0)
649 				pr_debug("%s: sctp_asconf_mgmt failed\n", __func__);
650 			bh_unlock_sock(sk);
651 		}
652 #if IS_ENABLED(CONFIG_IPV6)
653 free_next:
654 #endif
655 		list_del(&addrw->list);
656 		kfree(addrw);
657 	}
658 	spin_unlock_bh(&net->sctp.addr_wq_lock);
659 }
660 
661 static void sctp_free_addr_wq(struct net *net)
662 {
663 	struct sctp_sockaddr_entry *addrw;
664 	struct sctp_sockaddr_entry *temp;
665 
666 	spin_lock_bh(&net->sctp.addr_wq_lock);
667 	timer_delete(&net->sctp.addr_wq_timer);
668 	list_for_each_entry_safe(addrw, temp, &net->sctp.addr_waitq, list) {
669 		list_del(&addrw->list);
670 		kfree(addrw);
671 	}
672 	spin_unlock_bh(&net->sctp.addr_wq_lock);
673 }
674 
675 /* lookup the entry for the same address in the addr_waitq
676  * sctp_addr_wq MUST be locked
677  */
678 static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct net *net,
679 					struct sctp_sockaddr_entry *addr)
680 {
681 	struct sctp_sockaddr_entry *addrw;
682 
683 	list_for_each_entry(addrw, &net->sctp.addr_waitq, list) {
684 		if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
685 			continue;
686 		if (addrw->a.sa.sa_family == AF_INET) {
687 			if (addrw->a.v4.sin_addr.s_addr ==
688 			    addr->a.v4.sin_addr.s_addr)
689 				return addrw;
690 		} else if (addrw->a.sa.sa_family == AF_INET6) {
691 			if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
692 			    &addr->a.v6.sin6_addr))
693 				return addrw;
694 		}
695 	}
696 	return NULL;
697 }
698 
699 void sctp_addr_wq_mgmt(struct net *net, struct sctp_sockaddr_entry *addr, int cmd)
700 {
701 	struct sctp_sockaddr_entry *addrw;
702 	unsigned long timeo_val;
703 
704 	/* first, we check if an opposite message already exist in the queue.
705 	 * If we found such message, it is removed.
706 	 * This operation is a bit stupid, but the DHCP client attaches the
707 	 * new address after a couple of addition and deletion of that address
708 	 */
709 
710 	spin_lock_bh(&net->sctp.addr_wq_lock);
711 
712 	/* Avoid searching the queue or modifying it if there are no consumers,
713 	 * as it can lead to performance degradation if addresses are modified
714 	 * en-masse.
715 	 *
716 	 * If the queue already contains some events, update it anyway to avoid
717 	 * ugly races between new sessions and new address events.
718 	 */
719 	if (list_empty(&net->sctp.auto_asconf_splist) &&
720 	    list_empty(&net->sctp.addr_waitq)) {
721 		spin_unlock_bh(&net->sctp.addr_wq_lock);
722 		return;
723 	}
724 
725 	/* Offsets existing events in addr_wq */
726 	addrw = sctp_addr_wq_lookup(net, addr);
727 	if (addrw) {
728 		if (addrw->state != cmd) {
729 			pr_debug("%s: offsets existing entry for %d, addr:%pISc "
730 				 "in wq:%p\n", __func__, addrw->state, &addrw->a.sa,
731 				 &net->sctp.addr_waitq);
732 
733 			list_del(&addrw->list);
734 			kfree(addrw);
735 		}
736 		spin_unlock_bh(&net->sctp.addr_wq_lock);
737 		return;
738 	}
739 
740 	/* OK, we have to add the new address to the wait queue */
741 	addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
742 	if (addrw == NULL) {
743 		spin_unlock_bh(&net->sctp.addr_wq_lock);
744 		return;
745 	}
746 	addrw->state = cmd;
747 	list_add_tail(&addrw->list, &net->sctp.addr_waitq);
748 
749 	pr_debug("%s: add new entry for cmd:%d, addr:%pISc in wq:%p\n",
750 		 __func__, addrw->state, &addrw->a.sa, &net->sctp.addr_waitq);
751 
752 	if (!timer_pending(&net->sctp.addr_wq_timer)) {
753 		timeo_val = jiffies;
754 		timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
755 		mod_timer(&net->sctp.addr_wq_timer, timeo_val);
756 	}
757 	spin_unlock_bh(&net->sctp.addr_wq_lock);
758 }
759 
760 /* Event handler for inet address addition/deletion events.
761  * The sctp_local_addr_list needs to be protocted by a spin lock since
762  * multiple notifiers (say IPv4 and IPv6) may be running at the same
763  * time and thus corrupt the list.
764  * The reader side is protected with RCU.
765  */
766 static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
767 			       void *ptr)
768 {
769 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
770 	struct sctp_sockaddr_entry *addr = NULL;
771 	struct sctp_sockaddr_entry *temp;
772 	struct net *net = dev_net(ifa->ifa_dev->dev);
773 	int found = 0;
774 
775 	switch (ev) {
776 	case NETDEV_UP:
777 		addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
778 		if (addr) {
779 			addr->a.v4.sin_family = AF_INET;
780 			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
781 			addr->valid = 1;
782 			spin_lock_bh(&net->sctp.local_addr_lock);
783 			list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
784 			sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
785 			spin_unlock_bh(&net->sctp.local_addr_lock);
786 		}
787 		break;
788 	case NETDEV_DOWN:
789 		spin_lock_bh(&net->sctp.local_addr_lock);
790 		list_for_each_entry_safe(addr, temp,
791 					&net->sctp.local_addr_list, list) {
792 			if (addr->a.sa.sa_family == AF_INET &&
793 					addr->a.v4.sin_addr.s_addr ==
794 					ifa->ifa_local) {
795 				found = 1;
796 				addr->valid = 0;
797 				list_del_rcu(&addr->list);
798 				sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
799 				break;
800 			}
801 		}
802 		spin_unlock_bh(&net->sctp.local_addr_lock);
803 		if (found)
804 			kfree_rcu(addr, rcu);
805 		break;
806 	}
807 
808 	return NOTIFY_DONE;
809 }
810 
811 /*
812  * Initialize the control inode/socket with a control endpoint data
813  * structure.  This endpoint is reserved exclusively for the OOTB processing.
814  */
815 static int sctp_ctl_sock_init(struct net *net)
816 {
817 	int err;
818 	sa_family_t family = PF_INET;
819 
820 	if (sctp_get_pf_specific(PF_INET6))
821 		family = PF_INET6;
822 
823 	err = inet_ctl_sock_create(&net->sctp.ctl_sock, family,
824 				   SOCK_SEQPACKET, IPPROTO_SCTP, net);
825 
826 	/* If IPv6 socket could not be created, try the IPv4 socket */
827 	if (err < 0 && family == PF_INET6)
828 		err = inet_ctl_sock_create(&net->sctp.ctl_sock, AF_INET,
829 					   SOCK_SEQPACKET, IPPROTO_SCTP,
830 					   net);
831 
832 	if (err < 0) {
833 		pr_err("Failed to create the SCTP control socket\n");
834 		return err;
835 	}
836 	return 0;
837 }
838 
839 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
840 {
841 	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
842 
843 	skb_set_transport_header(skb, sizeof(struct udphdr));
844 	sctp_rcv(skb);
845 	return 0;
846 }
847 
848 int sctp_udp_sock_start(struct net *net)
849 {
850 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
851 	struct udp_port_cfg udp_conf = {0};
852 	struct socket *sock;
853 	int err;
854 
855 	udp_conf.family = AF_INET;
856 	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
857 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
858 	err = udp_sock_create(net, &udp_conf, &sock);
859 	if (err) {
860 		pr_err("Failed to create the SCTP UDP tunneling v4 sock\n");
861 		return err;
862 	}
863 
864 	tuncfg.encap_type = 1;
865 	tuncfg.encap_rcv = sctp_udp_rcv;
866 	tuncfg.encap_err_lookup = sctp_udp_v4_err;
867 	setup_udp_tunnel_sock(net, sock, &tuncfg);
868 	net->sctp.udp4_sock = sock->sk;
869 
870 #if IS_ENABLED(CONFIG_IPV6)
871 	memset(&udp_conf, 0, sizeof(udp_conf));
872 
873 	udp_conf.family = AF_INET6;
874 	udp_conf.local_ip6 = in6addr_any;
875 	udp_conf.local_udp_port = htons(net->sctp.udp_port);
876 	udp_conf.use_udp6_rx_checksums = true;
877 	udp_conf.ipv6_v6only = true;
878 	err = udp_sock_create(net, &udp_conf, &sock);
879 	if (err) {
880 		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
881 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
882 		net->sctp.udp4_sock = NULL;
883 		return err;
884 	}
885 
886 	tuncfg.encap_type = 1;
887 	tuncfg.encap_rcv = sctp_udp_rcv;
888 	tuncfg.encap_err_lookup = sctp_udp_v6_err;
889 	setup_udp_tunnel_sock(net, sock, &tuncfg);
890 	net->sctp.udp6_sock = sock->sk;
891 #endif
892 
893 	return 0;
894 }
895 
896 void sctp_udp_sock_stop(struct net *net)
897 {
898 	if (net->sctp.udp4_sock) {
899 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
900 		net->sctp.udp4_sock = NULL;
901 	}
902 	if (net->sctp.udp6_sock) {
903 		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
904 		net->sctp.udp6_sock = NULL;
905 	}
906 }
907 
908 /* Register address family specific functions. */
909 int sctp_register_af(struct sctp_af *af)
910 {
911 	switch (af->sa_family) {
912 	case AF_INET:
913 		if (sctp_af_v4_specific)
914 			return 0;
915 		sctp_af_v4_specific = af;
916 		break;
917 	case AF_INET6:
918 		if (sctp_af_v6_specific)
919 			return 0;
920 		sctp_af_v6_specific = af;
921 		break;
922 	default:
923 		return 0;
924 	}
925 
926 	INIT_LIST_HEAD(&af->list);
927 	list_add_tail(&af->list, &sctp_address_families);
928 	return 1;
929 }
930 
931 /* Get the table of functions for manipulating a particular address
932  * family.
933  */
934 struct sctp_af *sctp_get_af_specific(sa_family_t family)
935 {
936 	switch (family) {
937 	case AF_INET:
938 		return sctp_af_v4_specific;
939 	case AF_INET6:
940 		return sctp_af_v6_specific;
941 	default:
942 		return NULL;
943 	}
944 }
945 
946 /* Common code to initialize a AF_INET msg_name. */
947 static void sctp_inet_msgname(char *msgname, int *addr_len)
948 {
949 	struct sockaddr_in *sin;
950 
951 	sin = (struct sockaddr_in *)msgname;
952 	*addr_len = sizeof(struct sockaddr_in);
953 	sin->sin_family = AF_INET;
954 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
955 }
956 
957 /* Copy the primary address of the peer primary address as the msg_name. */
958 static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
959 				    int *addr_len)
960 {
961 	struct sockaddr_in *sin, *sinfrom;
962 
963 	if (msgname) {
964 		struct sctp_association *asoc;
965 
966 		asoc = event->asoc;
967 		sctp_inet_msgname(msgname, addr_len);
968 		sin = (struct sockaddr_in *)msgname;
969 		sinfrom = &asoc->peer.primary_addr.v4;
970 		sin->sin_port = htons(asoc->peer.port);
971 		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
972 	}
973 }
974 
975 /* Initialize and copy out a msgname from an inbound skb. */
976 static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
977 {
978 	if (msgname) {
979 		struct sctphdr *sh = sctp_hdr(skb);
980 		struct sockaddr_in *sin = (struct sockaddr_in *)msgname;
981 
982 		sctp_inet_msgname(msgname, len);
983 		sin->sin_port = sh->source;
984 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
985 	}
986 }
987 
988 /* Do we support this AF? */
989 static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
990 {
991 	/* PF_INET only supports AF_INET addresses. */
992 	return AF_INET == family;
993 }
994 
995 /* Address matching with wildcards allowed. */
996 static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
997 			      const union sctp_addr *addr2,
998 			      struct sctp_sock *opt)
999 {
1000 	/* PF_INET only supports AF_INET addresses. */
1001 	if (addr1->sa.sa_family != addr2->sa.sa_family)
1002 		return 0;
1003 	if (htonl(INADDR_ANY) == addr1->v4.sin_addr.s_addr ||
1004 	    htonl(INADDR_ANY) == addr2->v4.sin_addr.s_addr)
1005 		return 1;
1006 	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
1007 		return 1;
1008 
1009 	return 0;
1010 }
1011 
1012 /* Verify that provided sockaddr looks bindable.  Common verification has
1013  * already been taken care of.
1014  */
1015 static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
1016 {
1017 	return sctp_v4_available(addr, opt);
1018 }
1019 
1020 /* Verify that sockaddr looks sendable.  Common verification has already
1021  * been taken care of.
1022  */
1023 static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
1024 {
1025 	return 1;
1026 }
1027 
1028 /* Fill in Supported Address Type information for INIT and INIT-ACK
1029  * chunks.  Returns number of addresses supported.
1030  */
1031 static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
1032 				     __be16 *types)
1033 {
1034 	types[0] = SCTP_PARAM_IPV4_ADDRESS;
1035 	return 1;
1036 }
1037 
1038 /* Wrapper routine that calls the ip transmit routine. */
1039 static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
1040 {
1041 	struct dst_entry *dst = dst_clone(t->dst);
1042 	struct flowi4 *fl4 = &t->fl.u.ip4;
1043 	struct sock *sk = skb->sk;
1044 	struct inet_sock *inet = inet_sk(sk);
1045 	__u8 dscp = READ_ONCE(inet->tos);
1046 	__be16 df = 0;
1047 
1048 	pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
1049 		 skb->len, &fl4->saddr, &fl4->daddr);
1050 
1051 	if (t->dscp & SCTP_DSCP_SET_MASK)
1052 		dscp = t->dscp & SCTP_DSCP_VAL_MASK;
1053 
1054 	inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO
1055 							   : IP_PMTUDISC_DONT;
1056 	SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
1057 
1058 	if (!t->encap_port || !sctp_sk(sk)->udp_port) {
1059 		skb_dst_set(skb, dst);
1060 		return __ip_queue_xmit(sk, skb, &t->fl, dscp);
1061 	}
1062 
1063 	if (skb_is_gso(skb))
1064 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1065 
1066 	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
1067 		df = htons(IP_DF);
1068 
1069 	skb->encapsulation = 1;
1070 	skb_reset_inner_mac_header(skb);
1071 	skb_reset_inner_transport_header(skb);
1072 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
1073 	udp_tunnel_xmit_skb(dst_rtable(dst), sk, skb, fl4->saddr,
1074 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
1075 			    sctp_sk(sk)->udp_port, t->encap_port, false, false,
1076 			    0);
1077 	return 0;
1078 }
1079 
1080 static struct sctp_af sctp_af_inet;
1081 
1082 static struct sctp_pf sctp_pf_inet = {
1083 	.event_msgname = sctp_inet_event_msgname,
1084 	.skb_msgname   = sctp_inet_skb_msgname,
1085 	.af_supported  = sctp_inet_af_supported,
1086 	.cmp_addr      = sctp_inet_cmp_addr,
1087 	.bind_verify   = sctp_inet_bind_verify,
1088 	.send_verify   = sctp_inet_send_verify,
1089 	.supported_addrs = sctp_inet_supported_addrs,
1090 	.addr_to_user  = sctp_v4_addr_to_user,
1091 	.to_sk_saddr   = sctp_v4_to_sk_saddr,
1092 	.to_sk_daddr   = sctp_v4_to_sk_daddr,
1093 	.copy_ip_options = sctp_v4_copy_ip_options,
1094 	.af            = &sctp_af_inet
1095 };
1096 
1097 /* Notifier for inetaddr addition/deletion events.  */
1098 static struct notifier_block sctp_inetaddr_notifier = {
1099 	.notifier_call = sctp_inetaddr_event,
1100 };
1101 
1102 /* Socket operations.  */
1103 static const struct proto_ops inet_seqpacket_ops = {
1104 	.family		   = PF_INET,
1105 	.owner		   = THIS_MODULE,
1106 	.release	   = inet_release,	/* Needs to be wrapped... */
1107 	.bind		   = inet_bind,
1108 	.connect	   = sctp_inet_connect,
1109 	.socketpair	   = sock_no_socketpair,
1110 	.accept		   = inet_accept,
1111 	.getname	   = inet_getname,	/* Semantics are different.  */
1112 	.poll		   = sctp_poll,
1113 	.ioctl		   = inet_ioctl,
1114 	.gettstamp	   = sock_gettstamp,
1115 	.listen		   = sctp_inet_listen,
1116 	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
1117 	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
1118 	.getsockopt	   = sock_common_getsockopt,
1119 	.sendmsg	   = inet_sendmsg,
1120 	.recvmsg	   = inet_recvmsg,
1121 	.mmap		   = sock_no_mmap,
1122 };
1123 
1124 /* Registration with AF_INET family.  */
1125 static struct inet_protosw sctp_seqpacket_protosw = {
1126 	.type       = SOCK_SEQPACKET,
1127 	.protocol   = IPPROTO_SCTP,
1128 	.prot       = &sctp_prot,
1129 	.ops        = &inet_seqpacket_ops,
1130 	.flags      = SCTP_PROTOSW_FLAG
1131 };
1132 static struct inet_protosw sctp_stream_protosw = {
1133 	.type       = SOCK_STREAM,
1134 	.protocol   = IPPROTO_SCTP,
1135 	.prot       = &sctp_prot,
1136 	.ops        = &inet_seqpacket_ops,
1137 	.flags      = SCTP_PROTOSW_FLAG
1138 };
1139 
1140 static int sctp4_rcv(struct sk_buff *skb)
1141 {
1142 	SCTP_INPUT_CB(skb)->encap_port = 0;
1143 	return sctp_rcv(skb);
1144 }
1145 
1146 /* Register with IP layer.  */
1147 static const struct net_protocol sctp_protocol = {
1148 	.handler     = sctp4_rcv,
1149 	.err_handler = sctp_v4_err,
1150 	.no_policy   = 1,
1151 	.icmp_strict_tag_validation = 1,
1152 };
1153 
1154 /* IPv4 address related functions.  */
1155 static struct sctp_af sctp_af_inet = {
1156 	.sa_family	   = AF_INET,
1157 	.sctp_xmit	   = sctp_v4_xmit,
1158 	.setsockopt	   = ip_setsockopt,
1159 	.getsockopt	   = ip_getsockopt,
1160 	.get_dst	   = sctp_v4_get_dst,
1161 	.get_saddr	   = sctp_v4_get_saddr,
1162 	.copy_addrlist	   = sctp_v4_copy_addrlist,
1163 	.from_skb	   = sctp_v4_from_skb,
1164 	.from_sk	   = sctp_v4_from_sk,
1165 	.from_addr_param   = sctp_v4_from_addr_param,
1166 	.to_addr_param	   = sctp_v4_to_addr_param,
1167 	.cmp_addr	   = sctp_v4_cmp_addr,
1168 	.addr_valid	   = sctp_v4_addr_valid,
1169 	.inaddr_any	   = sctp_v4_inaddr_any,
1170 	.is_any		   = sctp_v4_is_any,
1171 	.available	   = sctp_v4_available,
1172 	.scope		   = sctp_v4_scope,
1173 	.skb_iif	   = sctp_v4_skb_iif,
1174 	.skb_sdif	   = sctp_v4_skb_sdif,
1175 	.is_ce		   = sctp_v4_is_ce,
1176 	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
1177 	.ecn_capable	   = sctp_v4_ecn_capable,
1178 	.net_header_len	   = sizeof(struct iphdr),
1179 	.sockaddr_len	   = sizeof(struct sockaddr_in),
1180 	.ip_options_len	   = sctp_v4_ip_options_len,
1181 };
1182 
1183 struct sctp_pf *sctp_get_pf_specific(sa_family_t family)
1184 {
1185 	switch (family) {
1186 	case PF_INET:
1187 		return sctp_pf_inet_specific;
1188 	case PF_INET6:
1189 		return sctp_pf_inet6_specific;
1190 	default:
1191 		return NULL;
1192 	}
1193 }
1194 
1195 /* Register the PF specific function table.  */
1196 int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
1197 {
1198 	switch (family) {
1199 	case PF_INET:
1200 		if (sctp_pf_inet_specific)
1201 			return 0;
1202 		sctp_pf_inet_specific = pf;
1203 		break;
1204 	case PF_INET6:
1205 		if (sctp_pf_inet6_specific)
1206 			return 0;
1207 		sctp_pf_inet6_specific = pf;
1208 		break;
1209 	default:
1210 		return 0;
1211 	}
1212 	return 1;
1213 }
1214 
1215 static inline int init_sctp_mibs(struct net *net)
1216 {
1217 	net->sctp.sctp_statistics = alloc_percpu(struct sctp_mib);
1218 	if (!net->sctp.sctp_statistics)
1219 		return -ENOMEM;
1220 	return 0;
1221 }
1222 
1223 static inline void cleanup_sctp_mibs(struct net *net)
1224 {
1225 	free_percpu(net->sctp.sctp_statistics);
1226 }
1227 
1228 static void sctp_v4_pf_init(void)
1229 {
1230 	/* Initialize the SCTP specific PF functions. */
1231 	sctp_register_pf(&sctp_pf_inet, PF_INET);
1232 	sctp_register_af(&sctp_af_inet);
1233 }
1234 
1235 static void sctp_v4_pf_exit(void)
1236 {
1237 	list_del(&sctp_af_inet.list);
1238 }
1239 
1240 static int sctp_v4_protosw_init(void)
1241 {
1242 	int rc;
1243 
1244 	rc = proto_register(&sctp_prot, 1);
1245 	if (rc)
1246 		return rc;
1247 
1248 	/* Register SCTP(UDP and TCP style) with socket layer.  */
1249 	inet_register_protosw(&sctp_seqpacket_protosw);
1250 	inet_register_protosw(&sctp_stream_protosw);
1251 
1252 	return 0;
1253 }
1254 
1255 static void sctp_v4_protosw_exit(void)
1256 {
1257 	inet_unregister_protosw(&sctp_stream_protosw);
1258 	inet_unregister_protosw(&sctp_seqpacket_protosw);
1259 	proto_unregister(&sctp_prot);
1260 }
1261 
1262 static int sctp_v4_add_protocol(void)
1263 {
1264 	/* Register notifier for inet address additions/deletions. */
1265 	register_inetaddr_notifier(&sctp_inetaddr_notifier);
1266 
1267 	/* Register SCTP with inet layer.  */
1268 	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
1269 		return -EAGAIN;
1270 
1271 	return 0;
1272 }
1273 
1274 static void sctp_v4_del_protocol(void)
1275 {
1276 	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
1277 	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
1278 }
1279 
1280 static int __net_init sctp_defaults_init(struct net *net)
1281 {
1282 	int status;
1283 
1284 	/*
1285 	 * 14. Suggested SCTP Protocol Parameter Values
1286 	 */
1287 	/* The following protocol parameters are RECOMMENDED:  */
1288 	/* RTO.Initial              - 3  seconds */
1289 	net->sctp.rto_initial			= SCTP_RTO_INITIAL;
1290 	/* RTO.Min                  - 1  second */
1291 	net->sctp.rto_min	 		= SCTP_RTO_MIN;
1292 	/* RTO.Max                 -  60 seconds */
1293 	net->sctp.rto_max 			= SCTP_RTO_MAX;
1294 	/* RTO.Alpha                - 1/8 */
1295 	net->sctp.rto_alpha			= SCTP_RTO_ALPHA;
1296 	/* RTO.Beta                 - 1/4 */
1297 	net->sctp.rto_beta			= SCTP_RTO_BETA;
1298 
1299 	/* Valid.Cookie.Life        - 60  seconds */
1300 	net->sctp.valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;
1301 
1302 	/* Whether Cookie Preservative is enabled(1) or not(0) */
1303 	net->sctp.cookie_preserve_enable 	= 1;
1304 
1305 	/* Whether cookie authentication is enabled(1) or not(0) */
1306 	net->sctp.cookie_auth_enable =
1307 		!IS_ENABLED(CONFIG_SCTP_DEFAULT_COOKIE_HMAC_NONE);
1308 
1309 	/* Max.Burst		    - 4 */
1310 	net->sctp.max_burst			= SCTP_DEFAULT_MAX_BURST;
1311 
1312 	/* Disable of Primary Path Switchover by default */
1313 	net->sctp.ps_retrans = SCTP_PS_RETRANS_MAX;
1314 
1315 	/* Enable pf state by default */
1316 	net->sctp.pf_enable = 1;
1317 
1318 	/* Ignore pf exposure feature by default */
1319 	net->sctp.pf_expose = SCTP_PF_EXPOSE_UNSET;
1320 
1321 	/* Association.Max.Retrans  - 10 attempts
1322 	 * Path.Max.Retrans         - 5  attempts (per destination address)
1323 	 * Max.Init.Retransmits     - 8  attempts
1324 	 */
1325 	net->sctp.max_retrans_association	= 10;
1326 	net->sctp.max_retrans_path		= 5;
1327 	net->sctp.max_retrans_init		= 8;
1328 
1329 	/* Sendbuffer growth	    - do per-socket accounting */
1330 	net->sctp.sndbuf_policy			= 0;
1331 
1332 	/* Rcvbuffer growth	    - do per-socket accounting */
1333 	net->sctp.rcvbuf_policy			= 0;
1334 
1335 	/* HB.interval              - 30 seconds */
1336 	net->sctp.hb_interval			= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
1337 
1338 	/* delayed SACK timeout */
1339 	net->sctp.sack_timeout			= SCTP_DEFAULT_TIMEOUT_SACK;
1340 
1341 	/* Disable ADDIP by default. */
1342 	net->sctp.addip_enable = 0;
1343 	net->sctp.addip_noauth = 0;
1344 	net->sctp.default_auto_asconf = 0;
1345 
1346 	/* Enable PR-SCTP by default. */
1347 	net->sctp.prsctp_enable = 1;
1348 
1349 	/* Disable RECONF by default. */
1350 	net->sctp.reconf_enable = 0;
1351 
1352 	/* Disable AUTH by default. */
1353 	net->sctp.auth_enable = 0;
1354 
1355 	/* Enable ECN by default. */
1356 	net->sctp.ecn_enable = 1;
1357 
1358 	/* Set UDP tunneling listening port to 0 by default */
1359 	net->sctp.udp_port = 0;
1360 
1361 	/* Set remote encap port to 0 by default */
1362 	net->sctp.encap_port = 0;
1363 
1364 	/* Set SCOPE policy to enabled */
1365 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
1366 
1367 	/* Set the default rwnd update threshold */
1368 	net->sctp.rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT;
1369 
1370 	/* Initialize maximum autoclose timeout. */
1371 	net->sctp.max_autoclose		= INT_MAX / HZ;
1372 
1373 #ifdef CONFIG_NET_L3_MASTER_DEV
1374 	net->sctp.l3mdev_accept = 1;
1375 #endif
1376 
1377 	status = sctp_sysctl_net_register(net);
1378 	if (status)
1379 		goto err_sysctl_register;
1380 
1381 	/* Allocate and initialise sctp mibs.  */
1382 	status = init_sctp_mibs(net);
1383 	if (status)
1384 		goto err_init_mibs;
1385 
1386 #ifdef CONFIG_PROC_FS
1387 	/* Initialize proc fs directory.  */
1388 	status = sctp_proc_init(net);
1389 	if (status)
1390 		goto err_init_proc;
1391 #endif
1392 
1393 	sctp_dbg_objcnt_init(net);
1394 
1395 	/* Initialize the local address list. */
1396 	INIT_LIST_HEAD(&net->sctp.local_addr_list);
1397 	spin_lock_init(&net->sctp.local_addr_lock);
1398 	sctp_get_local_addr_list(net);
1399 
1400 	/* Initialize the address event list */
1401 	INIT_LIST_HEAD(&net->sctp.addr_waitq);
1402 	INIT_LIST_HEAD(&net->sctp.auto_asconf_splist);
1403 	spin_lock_init(&net->sctp.addr_wq_lock);
1404 	net->sctp.addr_wq_timer.expires = 0;
1405 	timer_setup(&net->sctp.addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
1406 
1407 	return 0;
1408 
1409 #ifdef CONFIG_PROC_FS
1410 err_init_proc:
1411 	cleanup_sctp_mibs(net);
1412 #endif
1413 err_init_mibs:
1414 	sctp_sysctl_net_unregister(net);
1415 err_sysctl_register:
1416 	return status;
1417 }
1418 
1419 static void __net_exit sctp_defaults_exit(struct net *net)
1420 {
1421 	/* Free the local address list */
1422 	sctp_free_addr_wq(net);
1423 	sctp_free_local_addr_list(net);
1424 
1425 #ifdef CONFIG_PROC_FS
1426 	remove_proc_subtree("sctp", net->proc_net);
1427 	net->sctp.proc_net_sctp = NULL;
1428 #endif
1429 	cleanup_sctp_mibs(net);
1430 	sctp_sysctl_net_unregister(net);
1431 }
1432 
1433 static struct pernet_operations sctp_defaults_ops = {
1434 	.init = sctp_defaults_init,
1435 	.exit = sctp_defaults_exit,
1436 };
1437 
1438 static int __net_init sctp_ctrlsock_init(struct net *net)
1439 {
1440 	int status;
1441 
1442 	/* Initialize the control inode/socket for handling OOTB packets.  */
1443 	status = sctp_ctl_sock_init(net);
1444 	if (status)
1445 		pr_err("Failed to initialize the SCTP control sock\n");
1446 
1447 	return status;
1448 }
1449 
1450 static void __net_exit sctp_ctrlsock_exit(struct net *net)
1451 {
1452 	/* Free the control endpoint.  */
1453 	inet_ctl_sock_destroy(net->sctp.ctl_sock);
1454 }
1455 
1456 static struct pernet_operations sctp_ctrlsock_ops = {
1457 	.init = sctp_ctrlsock_init,
1458 	.exit = sctp_ctrlsock_exit,
1459 };
1460 
1461 /* Initialize the universe into something sensible.  */
1462 static __init int sctp_init(void)
1463 {
1464 	unsigned long nr_pages = totalram_pages();
1465 	unsigned long limit;
1466 	unsigned long goal;
1467 	int max_entry_order;
1468 	int num_entries;
1469 	int max_share;
1470 	int status;
1471 	int order;
1472 	int i;
1473 
1474 	sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
1475 
1476 	/* Allocate bind_bucket and chunk caches. */
1477 	status = -ENOBUFS;
1478 	sctp_bucket_cachep = KMEM_CACHE(sctp_bind_bucket, SLAB_HWCACHE_ALIGN);
1479 	if (!sctp_bucket_cachep)
1480 		goto out;
1481 
1482 	sctp_chunk_cachep = KMEM_CACHE(sctp_chunk, SLAB_HWCACHE_ALIGN);
1483 	if (!sctp_chunk_cachep)
1484 		goto err_chunk_cachep;
1485 
1486 	status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
1487 	if (status)
1488 		goto err_percpu_counter_init;
1489 
1490 	/* Implementation specific variables. */
1491 
1492 	/* Initialize default stream count setup information. */
1493 	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
1494 	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;
1495 
1496 	/* Initialize handle used for association ids. */
1497 	idr_init(&sctp_assocs_id);
1498 
1499 	limit = nr_free_buffer_pages() / 8;
1500 	limit = max(limit, 128UL);
1501 	sysctl_sctp_mem[0] = limit / 4 * 3;
1502 	sysctl_sctp_mem[1] = limit;
1503 	sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;
1504 
1505 	/* Set per-socket limits to no more than 1/128 the pressure threshold*/
1506 	limit = (sysctl_sctp_mem[1]) << (PAGE_SHIFT - 7);
1507 	max_share = min(4UL*1024*1024, limit);
1508 
1509 	sysctl_sctp_rmem[0] = PAGE_SIZE; /* give each asoc 1 page min */
1510 	sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
1511 	sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
1512 
1513 	sysctl_sctp_wmem[0] = PAGE_SIZE;
1514 	sysctl_sctp_wmem[1] = 16*1024;
1515 	sysctl_sctp_wmem[2] = max(64*1024, max_share);
1516 
1517 	/* Size and allocate the association hash table.
1518 	 * The methodology is similar to that of the tcp hash tables.
1519 	 * Though not identical.  Start by getting a goal size
1520 	 */
1521 	if (nr_pages >= (128 * 1024))
1522 		goal = nr_pages >> (22 - PAGE_SHIFT);
1523 	else
1524 		goal = nr_pages >> (24 - PAGE_SHIFT);
1525 
1526 	/* Then compute the page order for said goal */
1527 	order = get_order(goal);
1528 
1529 	/* Now compute the required page order for the maximum sized table we
1530 	 * want to create
1531 	 */
1532 	max_entry_order = get_order(MAX_SCTP_PORT_HASH_ENTRIES *
1533 				    sizeof(struct sctp_bind_hashbucket));
1534 
1535 	/* Limit the page order by that maximum hash table size */
1536 	order = min(order, max_entry_order);
1537 
1538 	/* Allocate and initialize the endpoint hash table.  */
1539 	sctp_ep_hashsize = 64;
1540 	sctp_ep_hashtable =
1541 		kmalloc_array(64, sizeof(struct sctp_hashbucket), GFP_KERNEL);
1542 	if (!sctp_ep_hashtable) {
1543 		pr_err("Failed endpoint_hash alloc\n");
1544 		status = -ENOMEM;
1545 		goto err_ehash_alloc;
1546 	}
1547 	for (i = 0; i < sctp_ep_hashsize; i++) {
1548 		rwlock_init(&sctp_ep_hashtable[i].lock);
1549 		INIT_HLIST_HEAD(&sctp_ep_hashtable[i].chain);
1550 	}
1551 
1552 	/* Allocate and initialize the SCTP port hash table.
1553 	 * Note that order is initalized to start at the max sized
1554 	 * table we want to support.  If we can't get that many pages
1555 	 * reduce the order and try again
1556 	 */
1557 	do {
1558 		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
1559 			__get_free_pages(GFP_KERNEL | __GFP_NOWARN, order);
1560 	} while (!sctp_port_hashtable && --order > 0);
1561 
1562 	if (!sctp_port_hashtable) {
1563 		pr_err("Failed bind hash alloc\n");
1564 		status = -ENOMEM;
1565 		goto err_bhash_alloc;
1566 	}
1567 
1568 	/* Now compute the number of entries that will fit in the
1569 	 * port hash space we allocated
1570 	 */
1571 	num_entries = (1UL << order) * PAGE_SIZE /
1572 		      sizeof(struct sctp_bind_hashbucket);
1573 
1574 	/* And finish by rounding it down to the nearest power of two.
1575 	 * This wastes some memory of course, but it's needed because
1576 	 * the hash function operates based on the assumption that
1577 	 * the number of entries is a power of two.
1578 	 */
1579 	sctp_port_hashsize = rounddown_pow_of_two(num_entries);
1580 
1581 	for (i = 0; i < sctp_port_hashsize; i++) {
1582 		spin_lock_init(&sctp_port_hashtable[i].lock);
1583 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
1584 	}
1585 
1586 	status = sctp_transport_hashtable_init();
1587 	if (status)
1588 		goto err_thash_alloc;
1589 
1590 	pr_info("Hash tables configured (bind %d/%d)\n", sctp_port_hashsize,
1591 		num_entries);
1592 
1593 	sctp_sysctl_register();
1594 
1595 	INIT_LIST_HEAD(&sctp_address_families);
1596 	sctp_v4_pf_init();
1597 	sctp_v6_pf_init();
1598 	sctp_sched_ops_init();
1599 
1600 	status = register_pernet_subsys(&sctp_defaults_ops);
1601 	if (status)
1602 		goto err_register_defaults;
1603 
1604 	status = sctp_v4_protosw_init();
1605 	if (status)
1606 		goto err_protosw_init;
1607 
1608 	status = sctp_v6_protosw_init();
1609 	if (status)
1610 		goto err_v6_protosw_init;
1611 
1612 	status = register_pernet_subsys(&sctp_ctrlsock_ops);
1613 	if (status)
1614 		goto err_register_ctrlsock;
1615 
1616 	status = sctp_v4_add_protocol();
1617 	if (status)
1618 		goto err_add_protocol;
1619 
1620 	/* Register SCTP with inet6 layer.  */
1621 	status = sctp_v6_add_protocol();
1622 	if (status)
1623 		goto err_v6_add_protocol;
1624 
1625 	if (sctp_offload_init() < 0)
1626 		pr_crit("%s: Cannot add SCTP protocol offload\n", __func__);
1627 
1628 out:
1629 	return status;
1630 err_v6_add_protocol:
1631 	sctp_v4_del_protocol();
1632 err_add_protocol:
1633 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1634 err_register_ctrlsock:
1635 	sctp_v6_protosw_exit();
1636 err_v6_protosw_init:
1637 	sctp_v4_protosw_exit();
1638 err_protosw_init:
1639 	unregister_pernet_subsys(&sctp_defaults_ops);
1640 err_register_defaults:
1641 	sctp_v4_pf_exit();
1642 	sctp_v6_pf_exit();
1643 	sctp_sysctl_unregister();
1644 	free_pages((unsigned long)sctp_port_hashtable,
1645 		   get_order(sctp_port_hashsize *
1646 			     sizeof(struct sctp_bind_hashbucket)));
1647 err_bhash_alloc:
1648 	sctp_transport_hashtable_destroy();
1649 err_thash_alloc:
1650 	kfree(sctp_ep_hashtable);
1651 err_ehash_alloc:
1652 	percpu_counter_destroy(&sctp_sockets_allocated);
1653 err_percpu_counter_init:
1654 	kmem_cache_destroy(sctp_chunk_cachep);
1655 err_chunk_cachep:
1656 	kmem_cache_destroy(sctp_bucket_cachep);
1657 	goto out;
1658 }
1659 
1660 /* Exit handler for the SCTP protocol.  */
1661 static __exit void sctp_exit(void)
1662 {
1663 	/* BUG.  This should probably do something useful like clean
1664 	 * up all the remaining associations and all that memory.
1665 	 */
1666 
1667 	/* Unregister with inet6/inet layers. */
1668 	sctp_v6_del_protocol();
1669 	sctp_v4_del_protocol();
1670 
1671 	unregister_pernet_subsys(&sctp_ctrlsock_ops);
1672 
1673 	/* Free protosw registrations */
1674 	sctp_v6_protosw_exit();
1675 	sctp_v4_protosw_exit();
1676 
1677 	unregister_pernet_subsys(&sctp_defaults_ops);
1678 
1679 	/* Unregister with socket layer. */
1680 	sctp_v6_pf_exit();
1681 	sctp_v4_pf_exit();
1682 
1683 	sctp_sysctl_unregister();
1684 
1685 	free_pages((unsigned long)sctp_port_hashtable,
1686 		   get_order(sctp_port_hashsize *
1687 			     sizeof(struct sctp_bind_hashbucket)));
1688 	kfree(sctp_ep_hashtable);
1689 	sctp_transport_hashtable_destroy();
1690 
1691 	percpu_counter_destroy(&sctp_sockets_allocated);
1692 
1693 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1694 
1695 	kmem_cache_destroy(sctp_chunk_cachep);
1696 	kmem_cache_destroy(sctp_bucket_cachep);
1697 }
1698 
1699 module_init(sctp_init);
1700 module_exit(sctp_exit);
1701 
1702 /*
1703  * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
1704  */
1705 MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
1706 MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-132");
1707 MODULE_AUTHOR("Linux Kernel SCTP developers <linux-sctp@vger.kernel.org>");
1708 MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
1709 module_param_named(no_checksums, sctp_checksum_disable, bool, 0644);
1710 MODULE_PARM_DESC(no_checksums, "Disable checksums computing and verification");
1711 MODULE_LICENSE("GPL");
1712