1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2003
3  * Copyright (c) Cisco 1999,2000
4  * Copyright (c) Motorola 1999,2000,2001
5  * Copyright (c) La Monte H.P. Yarroll 2001
6  *
7  * This file is part of the SCTP kernel implementation.
8  *
9  * A collection class to handle the storage of transport addresses.
10  *
11  * This SCTP implementation is free software;
12  * you can redistribute it and/or modify it under the terms of
13  * the GNU General Public License as published by
14  * the Free Software Foundation; either version 2, or (at your option)
15  * any later version.
16  *
17  * This SCTP implementation is distributed in the hope that it
18  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
19  *                 ************************
20  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
21  * See the GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with GNU CC; see the file COPYING.  If not, write to
25  * the Free Software Foundation, 59 Temple Place - Suite 330,
26  * Boston, MA 02111-1307, USA.
27  *
28  * Please send any bug reports or fixes you make to the
29  * email address(es):
30  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
31  *
32  * Or submit a bug report through the following website:
33  *    http://www.sf.net/projects/lksctp
34  *
35  * Written or modified by:
36  *    La Monte H.P. Yarroll <piggy@acm.org>
37  *    Karl Knutson          <karl@athena.chicago.il.us>
38  *    Jon Grimm             <jgrimm@us.ibm.com>
39  *    Daisy Chang           <daisyc@us.ibm.com>
40  *
41  * Any bugs reported given to us we will try to fix... any fixes shared will
42  * be incorporated into the next SCTP release.
43  */
44 
45 #include <linux/types.h>
46 #include <linux/slab.h>
47 #include <linux/in.h>
48 #include <net/sock.h>
49 #include <net/ipv6.h>
50 #include <net/if_inet6.h>
51 #include <net/sctp/sctp.h>
52 #include <net/sctp/sm.h>
53 
54 /* Forward declarations for internal helpers. */
55 static int sctp_copy_one_addr(struct sctp_bind_addr *, union sctp_addr *,
56 			      sctp_scope_t scope, gfp_t gfp,
57 			      int flags);
58 static void sctp_bind_addr_clean(struct sctp_bind_addr *);
59 
60 /* First Level Abstractions. */
61 
62 /* Copy 'src' to 'dest' taking 'scope' into account.  Omit addresses
63  * in 'src' which have a broader scope than 'scope'.
64  */
sctp_bind_addr_copy(struct sctp_bind_addr * dest,const struct sctp_bind_addr * src,sctp_scope_t scope,gfp_t gfp,int flags)65 int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
66 			const struct sctp_bind_addr *src,
67 			sctp_scope_t scope, gfp_t gfp,
68 			int flags)
69 {
70 	struct sctp_sockaddr_entry *addr;
71 	int error = 0;
72 
73 	/* All addresses share the same port.  */
74 	dest->port = src->port;
75 
76 	/* Extract the addresses which are relevant for this scope.  */
77 	list_for_each_entry(addr, &src->address_list, list) {
78 		error = sctp_copy_one_addr(dest, &addr->a, scope,
79 					   gfp, flags);
80 		if (error < 0)
81 			goto out;
82 	}
83 
84 	/* If there are no addresses matching the scope and
85 	 * this is global scope, try to get a link scope address, with
86 	 * the assumption that we must be sitting behind a NAT.
87 	 */
88 	if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {
89 		list_for_each_entry(addr, &src->address_list, list) {
90 			error = sctp_copy_one_addr(dest, &addr->a,
91 						   SCTP_SCOPE_LINK, gfp,
92 						   flags);
93 			if (error < 0)
94 				goto out;
95 		}
96 	}
97 
98 out:
99 	if (error)
100 		sctp_bind_addr_clean(dest);
101 
102 	return error;
103 }
104 
105 /* Exactly duplicate the address lists.  This is necessary when doing
106  * peer-offs and accepts.  We don't want to put all the current system
107  * addresses into the endpoint.  That's useless.  But we do want duplicat
108  * the list of bound addresses that the older endpoint used.
109  */
sctp_bind_addr_dup(struct sctp_bind_addr * dest,const struct sctp_bind_addr * src,gfp_t gfp)110 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
111 			const struct sctp_bind_addr *src,
112 			gfp_t gfp)
113 {
114 	struct sctp_sockaddr_entry *addr;
115 	int error = 0;
116 
117 	/* All addresses share the same port.  */
118 	dest->port = src->port;
119 
120 	list_for_each_entry(addr, &src->address_list, list) {
121 		error = sctp_add_bind_addr(dest, &addr->a, 1, gfp);
122 		if (error < 0)
123 			break;
124 	}
125 
126 	return error;
127 }
128 
129 /* Initialize the SCTP_bind_addr structure for either an endpoint or
130  * an association.
131  */
sctp_bind_addr_init(struct sctp_bind_addr * bp,__u16 port)132 void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
133 {
134 	bp->malloced = 0;
135 
136 	INIT_LIST_HEAD(&bp->address_list);
137 	bp->port = port;
138 }
139 
140 /* Dispose of the address list. */
sctp_bind_addr_clean(struct sctp_bind_addr * bp)141 static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
142 {
143 	struct sctp_sockaddr_entry *addr, *temp;
144 
145 	/* Empty the bind address list. */
146 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
147 		list_del_rcu(&addr->list);
148 		kfree_rcu(addr, rcu);
149 		SCTP_DBG_OBJCNT_DEC(addr);
150 	}
151 }
152 
153 /* Dispose of an SCTP_bind_addr structure  */
sctp_bind_addr_free(struct sctp_bind_addr * bp)154 void sctp_bind_addr_free(struct sctp_bind_addr *bp)
155 {
156 	/* Empty the bind address list. */
157 	sctp_bind_addr_clean(bp);
158 
159 	if (bp->malloced) {
160 		kfree(bp);
161 		SCTP_DBG_OBJCNT_DEC(bind_addr);
162 	}
163 }
164 
165 /* Add an address to the bind address list in the SCTP_bind_addr structure. */
sctp_add_bind_addr(struct sctp_bind_addr * bp,union sctp_addr * new,__u8 addr_state,gfp_t gfp)166 int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
167 		       __u8 addr_state, gfp_t gfp)
168 {
169 	struct sctp_sockaddr_entry *addr;
170 
171 	/* Add the address to the bind address list.  */
172 	addr = t_new(struct sctp_sockaddr_entry, gfp);
173 	if (!addr)
174 		return -ENOMEM;
175 
176 	memcpy(&addr->a, new, sizeof(*new));
177 
178 	/* Fix up the port if it has not yet been set.
179 	 * Both v4 and v6 have the port at the same offset.
180 	 */
181 	if (!addr->a.v4.sin_port)
182 		addr->a.v4.sin_port = htons(bp->port);
183 
184 	addr->state = addr_state;
185 	addr->valid = 1;
186 
187 	INIT_LIST_HEAD(&addr->list);
188 
189 	/* We always hold a socket lock when calling this function,
190 	 * and that acts as a writer synchronizing lock.
191 	 */
192 	list_add_tail_rcu(&addr->list, &bp->address_list);
193 	SCTP_DBG_OBJCNT_INC(addr);
194 
195 	return 0;
196 }
197 
198 /* Delete an address from the bind address list in the SCTP_bind_addr
199  * structure.
200  */
sctp_del_bind_addr(struct sctp_bind_addr * bp,union sctp_addr * del_addr)201 int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
202 {
203 	struct sctp_sockaddr_entry *addr, *temp;
204 	int found = 0;
205 
206 	/* We hold the socket lock when calling this function,
207 	 * and that acts as a writer synchronizing lock.
208 	 */
209 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
210 		if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
211 			/* Found the exact match. */
212 			found = 1;
213 			addr->valid = 0;
214 			list_del_rcu(&addr->list);
215 			break;
216 		}
217 	}
218 
219 	if (found) {
220 		kfree_rcu(addr, rcu);
221 		SCTP_DBG_OBJCNT_DEC(addr);
222 		return 0;
223 	}
224 
225 	return -EINVAL;
226 }
227 
228 /* Create a network byte-order representation of all the addresses
229  * formated as SCTP parameters.
230  *
231  * The second argument is the return value for the length.
232  */
sctp_bind_addrs_to_raw(const struct sctp_bind_addr * bp,int * addrs_len,gfp_t gfp)233 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
234 					 int *addrs_len,
235 					 gfp_t gfp)
236 {
237 	union sctp_params addrparms;
238 	union sctp_params retval;
239 	int addrparms_len;
240 	union sctp_addr_param rawaddr;
241 	int len;
242 	struct sctp_sockaddr_entry *addr;
243 	struct list_head *pos;
244 	struct sctp_af *af;
245 
246 	addrparms_len = 0;
247 	len = 0;
248 
249 	/* Allocate enough memory at once. */
250 	list_for_each(pos, &bp->address_list) {
251 		len += sizeof(union sctp_addr_param);
252 	}
253 
254 	/* Don't even bother embedding an address if there
255 	 * is only one.
256 	 */
257 	if (len == sizeof(union sctp_addr_param)) {
258 		retval.v = NULL;
259 		goto end_raw;
260 	}
261 
262 	retval.v = kmalloc(len, gfp);
263 	if (!retval.v)
264 		goto end_raw;
265 
266 	addrparms = retval;
267 
268 	list_for_each_entry(addr, &bp->address_list, list) {
269 		af = sctp_get_af_specific(addr->a.v4.sin_family);
270 		len = af->to_addr_param(&addr->a, &rawaddr);
271 		memcpy(addrparms.v, &rawaddr, len);
272 		addrparms.v += len;
273 		addrparms_len += len;
274 	}
275 
276 end_raw:
277 	*addrs_len = addrparms_len;
278 	return retval;
279 }
280 
281 /*
282  * Create an address list out of the raw address list format (IPv4 and IPv6
283  * address parameters).
284  */
sctp_raw_to_bind_addrs(struct sctp_bind_addr * bp,__u8 * raw_addr_list,int addrs_len,__u16 port,gfp_t gfp)285 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
286 			   int addrs_len, __u16 port, gfp_t gfp)
287 {
288 	union sctp_addr_param *rawaddr;
289 	struct sctp_paramhdr *param;
290 	union sctp_addr addr;
291 	int retval = 0;
292 	int len;
293 	struct sctp_af *af;
294 
295 	/* Convert the raw address to standard address format */
296 	while (addrs_len) {
297 		param = (struct sctp_paramhdr *)raw_addr_list;
298 		rawaddr = (union sctp_addr_param *)raw_addr_list;
299 
300 		af = sctp_get_af_specific(param_type2af(param->type));
301 		if (unlikely(!af)) {
302 			retval = -EINVAL;
303 			sctp_bind_addr_clean(bp);
304 			break;
305 		}
306 
307 		af->from_addr_param(&addr, rawaddr, htons(port), 0);
308 		retval = sctp_add_bind_addr(bp, &addr, SCTP_ADDR_SRC, gfp);
309 		if (retval) {
310 			/* Can't finish building the list, clean up. */
311 			sctp_bind_addr_clean(bp);
312 			break;
313 		}
314 
315 		len = ntohs(param->length);
316 		addrs_len -= len;
317 		raw_addr_list += len;
318 	}
319 
320 	return retval;
321 }
322 
323 /********************************************************************
324  * 2nd Level Abstractions
325  ********************************************************************/
326 
327 /* Does this contain a specified address?  Allow wildcarding. */
sctp_bind_addr_match(struct sctp_bind_addr * bp,const union sctp_addr * addr,struct sctp_sock * opt)328 int sctp_bind_addr_match(struct sctp_bind_addr *bp,
329 			 const union sctp_addr *addr,
330 			 struct sctp_sock *opt)
331 {
332 	struct sctp_sockaddr_entry *laddr;
333 	int match = 0;
334 
335 	rcu_read_lock();
336 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
337 		if (!laddr->valid)
338 			continue;
339 		if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
340 			match = 1;
341 			break;
342 		}
343 	}
344 	rcu_read_unlock();
345 
346 	return match;
347 }
348 
349 /* Does the address 'addr' conflict with any addresses in
350  * the bp.
351  */
sctp_bind_addr_conflict(struct sctp_bind_addr * bp,const union sctp_addr * addr,struct sctp_sock * bp_sp,struct sctp_sock * addr_sp)352 int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
353 			    const union sctp_addr *addr,
354 			    struct sctp_sock *bp_sp,
355 			    struct sctp_sock *addr_sp)
356 {
357 	struct sctp_sockaddr_entry *laddr;
358 	int conflict = 0;
359 	struct sctp_sock *sp;
360 
361 	/* Pick the IPv6 socket as the basis of comparison
362 	 * since it's usually a superset of the IPv4.
363 	 * If there is no IPv6 socket, then default to bind_addr.
364 	 */
365 	if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
366 		sp = bp_sp;
367 	else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
368 		sp = addr_sp;
369 	else
370 		sp = bp_sp;
371 
372 	rcu_read_lock();
373 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
374 		if (!laddr->valid)
375 			continue;
376 
377 		conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
378 		if (conflict)
379 			break;
380 	}
381 	rcu_read_unlock();
382 
383 	return conflict;
384 }
385 
386 /* Get the state of the entry in the bind_addr_list */
sctp_bind_addr_state(const struct sctp_bind_addr * bp,const union sctp_addr * addr)387 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
388 			 const union sctp_addr *addr)
389 {
390 	struct sctp_sockaddr_entry *laddr;
391 	struct sctp_af *af;
392 	int state = -1;
393 
394 	af = sctp_get_af_specific(addr->sa.sa_family);
395 	if (unlikely(!af))
396 		return state;
397 
398 	rcu_read_lock();
399 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
400 		if (!laddr->valid)
401 			continue;
402 		if (af->cmp_addr(&laddr->a, addr)) {
403 			state = laddr->state;
404 			break;
405 		}
406 	}
407 	rcu_read_unlock();
408 
409 	return state;
410 }
411 
412 /* Find the first address in the bind address list that is not present in
413  * the addrs packed array.
414  */
sctp_find_unmatch_addr(struct sctp_bind_addr * bp,const union sctp_addr * addrs,int addrcnt,struct sctp_sock * opt)415 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
416 					const union sctp_addr	*addrs,
417 					int			addrcnt,
418 					struct sctp_sock	*opt)
419 {
420 	struct sctp_sockaddr_entry	*laddr;
421 	union sctp_addr			*addr;
422 	void 				*addr_buf;
423 	struct sctp_af			*af;
424 	int				i;
425 
426 	/* This is only called sctp_send_asconf_del_ip() and we hold
427 	 * the socket lock in that code patch, so that address list
428 	 * can't change.
429 	 */
430 	list_for_each_entry(laddr, &bp->address_list, list) {
431 		addr_buf = (union sctp_addr *)addrs;
432 		for (i = 0; i < addrcnt; i++) {
433 			addr = addr_buf;
434 			af = sctp_get_af_specific(addr->v4.sin_family);
435 			if (!af)
436 				break;
437 
438 			if (opt->pf->cmp_addr(&laddr->a, addr, opt))
439 				break;
440 
441 			addr_buf += af->sockaddr_len;
442 		}
443 		if (i == addrcnt)
444 			return &laddr->a;
445 	}
446 
447 	return NULL;
448 }
449 
450 /* Copy out addresses from the global local address list. */
sctp_copy_one_addr(struct sctp_bind_addr * dest,union sctp_addr * addr,sctp_scope_t scope,gfp_t gfp,int flags)451 static int sctp_copy_one_addr(struct sctp_bind_addr *dest,
452 			      union sctp_addr *addr,
453 			      sctp_scope_t scope, gfp_t gfp,
454 			      int flags)
455 {
456 	int error = 0;
457 
458 	if (sctp_is_any(NULL, addr)) {
459 		error = sctp_copy_local_addr_list(dest, scope, gfp, flags);
460 	} else if (sctp_in_scope(addr, scope)) {
461 		/* Now that the address is in scope, check to see if
462 		 * the address type is supported by local sock as
463 		 * well as the remote peer.
464 		 */
465 		if ((((AF_INET == addr->sa.sa_family) &&
466 		      (flags & SCTP_ADDR4_PEERSUPP))) ||
467 		    (((AF_INET6 == addr->sa.sa_family) &&
468 		      (flags & SCTP_ADDR6_ALLOWED) &&
469 		      (flags & SCTP_ADDR6_PEERSUPP))))
470 			error = sctp_add_bind_addr(dest, addr, SCTP_ADDR_SRC,
471 						    gfp);
472 	}
473 
474 	return error;
475 }
476 
477 /* Is this a wildcard address?  */
sctp_is_any(struct sock * sk,const union sctp_addr * addr)478 int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
479 {
480 	unsigned short fam = 0;
481 	struct sctp_af *af;
482 
483 	/* Try to get the right address family */
484 	if (addr->sa.sa_family != AF_UNSPEC)
485 		fam = addr->sa.sa_family;
486 	else if (sk)
487 		fam = sk->sk_family;
488 
489 	af = sctp_get_af_specific(fam);
490 	if (!af)
491 		return 0;
492 
493 	return af->is_any(addr);
494 }
495 
496 /* Is 'addr' valid for 'scope'?  */
sctp_in_scope(const union sctp_addr * addr,sctp_scope_t scope)497 int sctp_in_scope(const union sctp_addr *addr, sctp_scope_t scope)
498 {
499 	sctp_scope_t addr_scope = sctp_scope(addr);
500 
501 	/* The unusable SCTP addresses will not be considered with
502 	 * any defined scopes.
503 	 */
504 	if (SCTP_SCOPE_UNUSABLE == addr_scope)
505 		return 0;
506 	/*
507 	 * For INIT and INIT-ACK address list, let L be the level of
508 	 * of requested destination address, sender and receiver
509 	 * SHOULD include all of its addresses with level greater
510 	 * than or equal to L.
511 	 *
512 	 * Address scoping can be selectively controlled via sysctl
513 	 * option
514 	 */
515 	switch (sctp_scope_policy) {
516 	case SCTP_SCOPE_POLICY_DISABLE:
517 		return 1;
518 	case SCTP_SCOPE_POLICY_ENABLE:
519 		if (addr_scope <= scope)
520 			return 1;
521 		break;
522 	case SCTP_SCOPE_POLICY_PRIVATE:
523 		if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
524 			return 1;
525 		break;
526 	case SCTP_SCOPE_POLICY_LINK:
527 		if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
528 			return 1;
529 		break;
530 	default:
531 		break;
532 	}
533 
534 	return 0;
535 }
536 
sctp_is_ep_boundall(struct sock * sk)537 int sctp_is_ep_boundall(struct sock *sk)
538 {
539 	struct sctp_bind_addr *bp;
540 	struct sctp_sockaddr_entry *addr;
541 
542 	bp = &sctp_sk(sk)->ep->base.bind_addr;
543 	if (sctp_list_single_entry(&bp->address_list)) {
544 		addr = list_entry(bp->address_list.next,
545 				  struct sctp_sockaddr_entry, list);
546 		if (sctp_is_any(sk, &addr->a))
547 			return 1;
548 	}
549 	return 0;
550 }
551 
552 /********************************************************************
553  * 3rd Level Abstractions
554  ********************************************************************/
555 
556 /* What is the scope of 'addr'?  */
sctp_scope(const union sctp_addr * addr)557 sctp_scope_t sctp_scope(const union sctp_addr *addr)
558 {
559 	struct sctp_af *af;
560 
561 	af = sctp_get_af_specific(addr->sa.sa_family);
562 	if (!af)
563 		return SCTP_SCOPE_UNUSABLE;
564 
565 	return af->scope((union sctp_addr *)addr);
566 }
567