xref: /openbmc/linux/net/sctp/ipv6.c (revision 384740dc)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2002, 2004
3  * Copyright (c) 2001 Nokia, Inc.
4  * Copyright (c) 2001 La Monte H.P. Yarroll
5  * Copyright (c) 2002-2003 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * SCTP over IPv6.
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  *    Le Yanqun		    <yanqun.le@nokia.com>
37  *    Hui Huang		    <hui.huang@nokia.com>
38  *    La Monte H.P. Yarroll <piggy@acm.org>
39  *    Sridhar Samudrala	    <sri@us.ibm.com>
40  *    Jon Grimm		    <jgrimm@us.ibm.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *
43  * Based on:
44  *	linux/net/ipv6/tcp_ipv6.c
45  *
46  * Any bugs reported given to us we will try to fix... any fixes shared will
47  * be incorporated into the next SCTP release.
48  */
49 
50 #include <linux/module.h>
51 #include <linux/errno.h>
52 #include <linux/types.h>
53 #include <linux/socket.h>
54 #include <linux/sockios.h>
55 #include <linux/net.h>
56 #include <linux/in.h>
57 #include <linux/in6.h>
58 #include <linux/netdevice.h>
59 #include <linux/init.h>
60 #include <linux/ipsec.h>
61 
62 #include <linux/ipv6.h>
63 #include <linux/icmpv6.h>
64 #include <linux/random.h>
65 #include <linux/seq_file.h>
66 
67 #include <net/protocol.h>
68 #include <net/ndisc.h>
69 #include <net/ip.h>
70 #include <net/ipv6.h>
71 #include <net/transp_v6.h>
72 #include <net/addrconf.h>
73 #include <net/ip6_route.h>
74 #include <net/inet_common.h>
75 #include <net/inet_ecn.h>
76 #include <net/sctp/sctp.h>
77 
78 #include <asm/uaccess.h>
79 
80 /* Event handler for inet6 address addition/deletion events.
81  * The sctp_local_addr_list needs to be protocted by a spin lock since
82  * multiple notifiers (say IPv4 and IPv6) may be running at the same
83  * time and thus corrupt the list.
84  * The reader side is protected with RCU.
85  */
86 static int sctp_inet6addr_event(struct notifier_block *this, unsigned long ev,
87 				void *ptr)
88 {
89 	struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
90 	struct sctp_sockaddr_entry *addr = NULL;
91 	struct sctp_sockaddr_entry *temp;
92 	int found = 0;
93 
94 	switch (ev) {
95 	case NETDEV_UP:
96 		addr = kmalloc(sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
97 		if (addr) {
98 			addr->a.v6.sin6_family = AF_INET6;
99 			addr->a.v6.sin6_port = 0;
100 			memcpy(&addr->a.v6.sin6_addr, &ifa->addr,
101 				 sizeof(struct in6_addr));
102 			addr->a.v6.sin6_scope_id = ifa->idev->dev->ifindex;
103 			addr->valid = 1;
104 			spin_lock_bh(&sctp_local_addr_lock);
105 			list_add_tail_rcu(&addr->list, &sctp_local_addr_list);
106 			spin_unlock_bh(&sctp_local_addr_lock);
107 		}
108 		break;
109 	case NETDEV_DOWN:
110 		spin_lock_bh(&sctp_local_addr_lock);
111 		list_for_each_entry_safe(addr, temp,
112 					&sctp_local_addr_list, list) {
113 			if (addr->a.sa.sa_family == AF_INET6 &&
114 					ipv6_addr_equal(&addr->a.v6.sin6_addr,
115 						&ifa->addr)) {
116 				found = 1;
117 				addr->valid = 0;
118 				list_del_rcu(&addr->list);
119 				break;
120 			}
121 		}
122 		spin_unlock_bh(&sctp_local_addr_lock);
123 		if (found)
124 			call_rcu(&addr->rcu, sctp_local_addr_free);
125 		break;
126 	}
127 
128 	return NOTIFY_DONE;
129 }
130 
131 static struct notifier_block sctp_inet6addr_notifier = {
132 	.notifier_call = sctp_inet6addr_event,
133 };
134 
135 /* ICMP error handler. */
136 SCTP_STATIC void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
137 			     int type, int code, int offset, __be32 info)
138 {
139 	struct inet6_dev *idev;
140 	struct sock *sk;
141 	struct sctp_association *asoc;
142 	struct sctp_transport *transport;
143 	struct ipv6_pinfo *np;
144 	sk_buff_data_t saveip, savesctp;
145 	int err;
146 
147 	idev = in6_dev_get(skb->dev);
148 
149 	/* Fix up skb to look at the embedded net header. */
150 	saveip	 = skb->network_header;
151 	savesctp = skb->transport_header;
152 	skb_reset_network_header(skb);
153 	skb_set_transport_header(skb, offset);
154 	sk = sctp_err_lookup(AF_INET6, skb, sctp_hdr(skb), &asoc, &transport);
155 	/* Put back, the original pointers. */
156 	skb->network_header   = saveip;
157 	skb->transport_header = savesctp;
158 	if (!sk) {
159 		ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
160 		goto out;
161 	}
162 
163 	/* Warning:  The sock lock is held.  Remember to call
164 	 * sctp_err_finish!
165 	 */
166 
167 	switch (type) {
168 	case ICMPV6_PKT_TOOBIG:
169 		sctp_icmp_frag_needed(sk, asoc, transport, ntohl(info));
170 		goto out_unlock;
171 	case ICMPV6_PARAMPROB:
172 		if (ICMPV6_UNK_NEXTHDR == code) {
173 			sctp_icmp_proto_unreachable(sk, asoc, transport);
174 			goto out_unlock;
175 		}
176 		break;
177 	default:
178 		break;
179 	}
180 
181 	np = inet6_sk(sk);
182 	icmpv6_err_convert(type, code, &err);
183 	if (!sock_owned_by_user(sk) && np->recverr) {
184 		sk->sk_err = err;
185 		sk->sk_error_report(sk);
186 	} else {  /* Only an error on timeout */
187 		sk->sk_err_soft = err;
188 	}
189 
190 out_unlock:
191 	sctp_err_finish(sk, asoc);
192 out:
193 	if (likely(idev != NULL))
194 		in6_dev_put(idev);
195 }
196 
197 /* Based on tcp_v6_xmit() in tcp_ipv6.c. */
198 static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)
199 {
200 	struct sock *sk = skb->sk;
201 	struct ipv6_pinfo *np = inet6_sk(sk);
202 	struct flowi fl;
203 
204 	memset(&fl, 0, sizeof(fl));
205 
206 	fl.proto = sk->sk_protocol;
207 
208 	/* Fill in the dest address from the route entry passed with the skb
209 	 * and the source address from the transport.
210 	 */
211 	ipv6_addr_copy(&fl.fl6_dst, &transport->ipaddr.v6.sin6_addr);
212 	ipv6_addr_copy(&fl.fl6_src, &transport->saddr.v6.sin6_addr);
213 
214 	fl.fl6_flowlabel = np->flow_label;
215 	IP6_ECN_flow_xmit(sk, fl.fl6_flowlabel);
216 	if (ipv6_addr_type(&fl.fl6_src) & IPV6_ADDR_LINKLOCAL)
217 		fl.oif = transport->saddr.v6.sin6_scope_id;
218 	else
219 		fl.oif = sk->sk_bound_dev_if;
220 
221 	if (np->opt && np->opt->srcrt) {
222 		struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
223 		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
224 	}
225 
226 	SCTP_DEBUG_PRINTK("%s: skb:%p, len:%d, "
227 			  "src:" NIP6_FMT " dst:" NIP6_FMT "\n",
228 			  __func__, skb, skb->len,
229 			  NIP6(fl.fl6_src), NIP6(fl.fl6_dst));
230 
231 	SCTP_INC_STATS(SCTP_MIB_OUTSCTPPACKS);
232 
233 	if (!(transport->param_flags & SPP_PMTUD_ENABLE))
234 		skb->local_df = 1;
235 
236 	return ip6_xmit(sk, skb, &fl, np->opt, 0);
237 }
238 
239 /* Returns the dst cache entry for the given source and destination ip
240  * addresses.
241  */
242 static struct dst_entry *sctp_v6_get_dst(struct sctp_association *asoc,
243 					 union sctp_addr *daddr,
244 					 union sctp_addr *saddr)
245 {
246 	struct dst_entry *dst;
247 	struct flowi fl;
248 
249 	memset(&fl, 0, sizeof(fl));
250 	ipv6_addr_copy(&fl.fl6_dst, &daddr->v6.sin6_addr);
251 	if (ipv6_addr_type(&daddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
252 		fl.oif = daddr->v6.sin6_scope_id;
253 
254 
255 	SCTP_DEBUG_PRINTK("%s: DST=" NIP6_FMT " ",
256 			  __func__, NIP6(fl.fl6_dst));
257 
258 	if (saddr) {
259 		ipv6_addr_copy(&fl.fl6_src, &saddr->v6.sin6_addr);
260 		SCTP_DEBUG_PRINTK(
261 			"SRC=" NIP6_FMT " - ",
262 			NIP6(fl.fl6_src));
263 	}
264 
265 	dst = ip6_route_output(&init_net, NULL, &fl);
266 	if (!dst->error) {
267 		struct rt6_info *rt;
268 		rt = (struct rt6_info *)dst;
269 		SCTP_DEBUG_PRINTK(
270 			"rt6_dst:" NIP6_FMT " rt6_src:" NIP6_FMT "\n",
271 			NIP6(rt->rt6i_dst.addr), NIP6(rt->rt6i_src.addr));
272 		return dst;
273 	}
274 	SCTP_DEBUG_PRINTK("NO ROUTE\n");
275 	dst_release(dst);
276 	return NULL;
277 }
278 
279 /* Returns the number of consecutive initial bits that match in the 2 ipv6
280  * addresses.
281  */
282 static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
283 					 union sctp_addr *s2)
284 {
285 	struct in6_addr *a1 = &s1->v6.sin6_addr;
286 	struct in6_addr *a2 = &s2->v6.sin6_addr;
287 	int i, j;
288 
289 	for (i = 0; i < 4 ; i++) {
290 		__be32 a1xora2;
291 
292 		a1xora2 = a1->s6_addr32[i] ^ a2->s6_addr32[i];
293 
294 		if ((j = fls(ntohl(a1xora2))))
295 			return (i * 32 + 32 - j);
296 	}
297 
298 	return (i*32);
299 }
300 
301 /* Fills in the source address(saddr) based on the destination address(daddr)
302  * and asoc's bind address list.
303  */
304 static void sctp_v6_get_saddr(struct sctp_sock *sk,
305 			      struct sctp_association *asoc,
306 			      struct dst_entry *dst,
307 			      union sctp_addr *daddr,
308 			      union sctp_addr *saddr)
309 {
310 	struct sctp_bind_addr *bp;
311 	struct sctp_sockaddr_entry *laddr;
312 	sctp_scope_t scope;
313 	union sctp_addr *baddr = NULL;
314 	__u8 matchlen = 0;
315 	__u8 bmatchlen;
316 
317 	SCTP_DEBUG_PRINTK("%s: asoc:%p dst:%p "
318 			  "daddr:" NIP6_FMT " ",
319 			  __func__, asoc, dst, NIP6(daddr->v6.sin6_addr));
320 
321 	if (!asoc) {
322 		ipv6_dev_get_saddr(sock_net(sctp_opt2sk(sk)),
323 				   dst ? ip6_dst_idev(dst)->dev : NULL,
324 				   &daddr->v6.sin6_addr,
325 				   inet6_sk(&sk->inet.sk)->srcprefs,
326 				   &saddr->v6.sin6_addr);
327 		SCTP_DEBUG_PRINTK("saddr from ipv6_get_saddr: " NIP6_FMT "\n",
328 				  NIP6(saddr->v6.sin6_addr));
329 		return;
330 	}
331 
332 	scope = sctp_scope(daddr);
333 
334 	bp = &asoc->base.bind_addr;
335 
336 	/* Go through the bind address list and find the best source address
337 	 * that matches the scope of the destination address.
338 	 */
339 	rcu_read_lock();
340 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
341 		if (!laddr->valid)
342 			continue;
343 		if ((laddr->state == SCTP_ADDR_SRC) &&
344 		    (laddr->a.sa.sa_family == AF_INET6) &&
345 		    (scope <= sctp_scope(&laddr->a))) {
346 			bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
347 			if (!baddr || (matchlen < bmatchlen)) {
348 				baddr = &laddr->a;
349 				matchlen = bmatchlen;
350 			}
351 		}
352 	}
353 
354 	if (baddr) {
355 		memcpy(saddr, baddr, sizeof(union sctp_addr));
356 		SCTP_DEBUG_PRINTK("saddr: " NIP6_FMT "\n",
357 				  NIP6(saddr->v6.sin6_addr));
358 	} else {
359 		printk(KERN_ERR "%s: asoc:%p Could not find a valid source "
360 		       "address for the dest:" NIP6_FMT "\n",
361 		       __func__, asoc, NIP6(daddr->v6.sin6_addr));
362 	}
363 
364 	rcu_read_unlock();
365 }
366 
367 /* Make a copy of all potential local addresses. */
368 static void sctp_v6_copy_addrlist(struct list_head *addrlist,
369 				  struct net_device *dev)
370 {
371 	struct inet6_dev *in6_dev;
372 	struct inet6_ifaddr *ifp;
373 	struct sctp_sockaddr_entry *addr;
374 
375 	rcu_read_lock();
376 	if ((in6_dev = __in6_dev_get(dev)) == NULL) {
377 		rcu_read_unlock();
378 		return;
379 	}
380 
381 	read_lock_bh(&in6_dev->lock);
382 	for (ifp = in6_dev->addr_list; ifp; ifp = ifp->if_next) {
383 		/* Add the address to the local list.  */
384 		addr = t_new(struct sctp_sockaddr_entry, GFP_ATOMIC);
385 		if (addr) {
386 			addr->a.v6.sin6_family = AF_INET6;
387 			addr->a.v6.sin6_port = 0;
388 			addr->a.v6.sin6_addr = ifp->addr;
389 			addr->a.v6.sin6_scope_id = dev->ifindex;
390 			addr->valid = 1;
391 			INIT_LIST_HEAD(&addr->list);
392 			INIT_RCU_HEAD(&addr->rcu);
393 			list_add_tail(&addr->list, addrlist);
394 		}
395 	}
396 
397 	read_unlock_bh(&in6_dev->lock);
398 	rcu_read_unlock();
399 }
400 
401 /* Initialize a sockaddr_storage from in incoming skb. */
402 static void sctp_v6_from_skb(union sctp_addr *addr,struct sk_buff *skb,
403 			     int is_saddr)
404 {
405 	void *from;
406 	__be16 *port;
407 	struct sctphdr *sh;
408 
409 	port = &addr->v6.sin6_port;
410 	addr->v6.sin6_family = AF_INET6;
411 	addr->v6.sin6_flowinfo = 0; /* FIXME */
412 	addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;
413 
414 	sh = sctp_hdr(skb);
415 	if (is_saddr) {
416 		*port  = sh->source;
417 		from = &ipv6_hdr(skb)->saddr;
418 	} else {
419 		*port = sh->dest;
420 		from = &ipv6_hdr(skb)->daddr;
421 	}
422 	ipv6_addr_copy(&addr->v6.sin6_addr, from);
423 }
424 
425 /* Initialize an sctp_addr from a socket. */
426 static void sctp_v6_from_sk(union sctp_addr *addr, struct sock *sk)
427 {
428 	addr->v6.sin6_family = AF_INET6;
429 	addr->v6.sin6_port = 0;
430 	addr->v6.sin6_addr = inet6_sk(sk)->rcv_saddr;
431 }
432 
433 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
434 static void sctp_v6_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
435 {
436 	if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
437 		inet6_sk(sk)->rcv_saddr.s6_addr32[0] = 0;
438 		inet6_sk(sk)->rcv_saddr.s6_addr32[1] = 0;
439 		inet6_sk(sk)->rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
440 		inet6_sk(sk)->rcv_saddr.s6_addr32[3] =
441 			addr->v4.sin_addr.s_addr;
442 	} else {
443 		inet6_sk(sk)->rcv_saddr = addr->v6.sin6_addr;
444 	}
445 }
446 
447 /* Initialize sk->sk_daddr from sctp_addr. */
448 static void sctp_v6_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
449 {
450 	if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
451 		inet6_sk(sk)->daddr.s6_addr32[0] = 0;
452 		inet6_sk(sk)->daddr.s6_addr32[1] = 0;
453 		inet6_sk(sk)->daddr.s6_addr32[2] = htonl(0x0000ffff);
454 		inet6_sk(sk)->daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
455 	} else {
456 		inet6_sk(sk)->daddr = addr->v6.sin6_addr;
457 	}
458 }
459 
460 /* Initialize a sctp_addr from an address parameter. */
461 static void sctp_v6_from_addr_param(union sctp_addr *addr,
462 				    union sctp_addr_param *param,
463 				    __be16 port, int iif)
464 {
465 	addr->v6.sin6_family = AF_INET6;
466 	addr->v6.sin6_port = port;
467 	addr->v6.sin6_flowinfo = 0; /* BUG */
468 	ipv6_addr_copy(&addr->v6.sin6_addr, &param->v6.addr);
469 	addr->v6.sin6_scope_id = iif;
470 }
471 
472 /* Initialize an address parameter from a sctp_addr and return the length
473  * of the address parameter.
474  */
475 static int sctp_v6_to_addr_param(const union sctp_addr *addr,
476 				 union sctp_addr_param *param)
477 {
478 	int length = sizeof(sctp_ipv6addr_param_t);
479 
480 	param->v6.param_hdr.type = SCTP_PARAM_IPV6_ADDRESS;
481 	param->v6.param_hdr.length = htons(length);
482 	ipv6_addr_copy(&param->v6.addr, &addr->v6.sin6_addr);
483 
484 	return length;
485 }
486 
487 /* Initialize a sctp_addr from a dst_entry. */
488 static void sctp_v6_dst_saddr(union sctp_addr *addr, struct dst_entry *dst,
489 			      __be16 port)
490 {
491 	struct rt6_info *rt = (struct rt6_info *)dst;
492 	addr->sa.sa_family = AF_INET6;
493 	addr->v6.sin6_port = port;
494 	ipv6_addr_copy(&addr->v6.sin6_addr, &rt->rt6i_src.addr);
495 }
496 
497 /* Compare addresses exactly.
498  * v4-mapped-v6 is also in consideration.
499  */
500 static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
501 			    const union sctp_addr *addr2)
502 {
503 	if (addr1->sa.sa_family != addr2->sa.sa_family) {
504 		if (addr1->sa.sa_family == AF_INET &&
505 		    addr2->sa.sa_family == AF_INET6 &&
506 		    ipv6_addr_v4mapped(&addr2->v6.sin6_addr)) {
507 			if (addr2->v6.sin6_port == addr1->v4.sin_port &&
508 			    addr2->v6.sin6_addr.s6_addr32[3] ==
509 			    addr1->v4.sin_addr.s_addr)
510 				return 1;
511 		}
512 		if (addr2->sa.sa_family == AF_INET &&
513 		    addr1->sa.sa_family == AF_INET6 &&
514 		    ipv6_addr_v4mapped(&addr1->v6.sin6_addr)) {
515 			if (addr1->v6.sin6_port == addr2->v4.sin_port &&
516 			    addr1->v6.sin6_addr.s6_addr32[3] ==
517 			    addr2->v4.sin_addr.s_addr)
518 				return 1;
519 		}
520 		return 0;
521 	}
522 	if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
523 		return 0;
524 	/* If this is a linklocal address, compare the scope_id. */
525 	if (ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
526 		if (addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
527 		    (addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)) {
528 			return 0;
529 		}
530 	}
531 
532 	return 1;
533 }
534 
535 /* Initialize addr struct to INADDR_ANY. */
536 static void sctp_v6_inaddr_any(union sctp_addr *addr, __be16 port)
537 {
538 	memset(addr, 0x00, sizeof(union sctp_addr));
539 	addr->v6.sin6_family = AF_INET6;
540 	addr->v6.sin6_port = port;
541 }
542 
543 /* Is this a wildcard address? */
544 static int sctp_v6_is_any(const union sctp_addr *addr)
545 {
546 	return ipv6_addr_any(&addr->v6.sin6_addr);
547 }
548 
549 /* Should this be available for binding?   */
550 static int sctp_v6_available(union sctp_addr *addr, struct sctp_sock *sp)
551 {
552 	int type;
553 	struct in6_addr *in6 = (struct in6_addr *)&addr->v6.sin6_addr;
554 
555 	type = ipv6_addr_type(in6);
556 	if (IPV6_ADDR_ANY == type)
557 		return 1;
558 	if (type == IPV6_ADDR_MAPPED) {
559 		if (sp && !sp->v4mapped)
560 			return 0;
561 		if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
562 			return 0;
563 		sctp_v6_map_v4(addr);
564 		return sctp_get_af_specific(AF_INET)->available(addr, sp);
565 	}
566 	if (!(type & IPV6_ADDR_UNICAST))
567 		return 0;
568 
569 	return ipv6_chk_addr(&init_net, in6, NULL, 0);
570 }
571 
572 /* This function checks if the address is a valid address to be used for
573  * SCTP.
574  *
575  * Output:
576  * Return 0 - If the address is a non-unicast or an illegal address.
577  * Return 1 - If the address is a unicast.
578  */
579 static int sctp_v6_addr_valid(union sctp_addr *addr,
580 			      struct sctp_sock *sp,
581 			      const struct sk_buff *skb)
582 {
583 	int ret = ipv6_addr_type(&addr->v6.sin6_addr);
584 
585 	/* Support v4-mapped-v6 address. */
586 	if (ret == IPV6_ADDR_MAPPED) {
587 		/* Note: This routine is used in input, so v4-mapped-v6
588 		 * are disallowed here when there is no sctp_sock.
589 		 */
590 		if (!sp || !sp->v4mapped)
591 			return 0;
592 		if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
593 			return 0;
594 		sctp_v6_map_v4(addr);
595 		return sctp_get_af_specific(AF_INET)->addr_valid(addr, sp, skb);
596 	}
597 
598 	/* Is this a non-unicast address */
599 	if (!(ret & IPV6_ADDR_UNICAST))
600 		return 0;
601 
602 	return 1;
603 }
604 
605 /* What is the scope of 'addr'?  */
606 static sctp_scope_t sctp_v6_scope(union sctp_addr *addr)
607 {
608 	int v6scope;
609 	sctp_scope_t retval;
610 
611 	/* The IPv6 scope is really a set of bit fields.
612 	 * See IFA_* in <net/if_inet6.h>.  Map to a generic SCTP scope.
613 	 */
614 
615 	v6scope = ipv6_addr_scope(&addr->v6.sin6_addr);
616 	switch (v6scope) {
617 	case IFA_HOST:
618 		retval = SCTP_SCOPE_LOOPBACK;
619 		break;
620 	case IFA_LINK:
621 		retval = SCTP_SCOPE_LINK;
622 		break;
623 	case IFA_SITE:
624 		retval = SCTP_SCOPE_PRIVATE;
625 		break;
626 	default:
627 		retval = SCTP_SCOPE_GLOBAL;
628 		break;
629 	}
630 
631 	return retval;
632 }
633 
634 /* Create and initialize a new sk for the socket to be returned by accept(). */
635 static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
636 					     struct sctp_association *asoc)
637 {
638 	struct inet_sock *inet = inet_sk(sk);
639 	struct sock *newsk;
640 	struct inet_sock *newinet;
641 	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
642 	struct sctp6_sock *newsctp6sk;
643 
644 	newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot);
645 	if (!newsk)
646 		goto out;
647 
648 	sock_init_data(NULL, newsk);
649 
650 	newsk->sk_type = SOCK_STREAM;
651 
652 	newsk->sk_prot = sk->sk_prot;
653 	newsk->sk_no_check = sk->sk_no_check;
654 	newsk->sk_reuse = sk->sk_reuse;
655 
656 	newsk->sk_destruct = inet_sock_destruct;
657 	newsk->sk_family = PF_INET6;
658 	newsk->sk_protocol = IPPROTO_SCTP;
659 	newsk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
660 	newsk->sk_shutdown = sk->sk_shutdown;
661 	sock_reset_flag(sk, SOCK_ZAPPED);
662 
663 	newsctp6sk = (struct sctp6_sock *)newsk;
664 	inet_sk(newsk)->pinet6 = &newsctp6sk->inet6;
665 
666 	sctp_sk(newsk)->v4mapped = sctp_sk(sk)->v4mapped;
667 
668 	newinet = inet_sk(newsk);
669 	newnp = inet6_sk(newsk);
670 
671 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
672 
673 	/* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
674 	 * and getpeername().
675 	 */
676 	newinet->sport = inet->sport;
677 	newnp->saddr = np->saddr;
678 	newnp->rcv_saddr = np->rcv_saddr;
679 	newinet->dport = htons(asoc->peer.port);
680 	sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);
681 
682 	/* Init the ipv4 part of the socket since we can have sockets
683 	 * using v6 API for ipv4.
684 	 */
685 	newinet->uc_ttl = -1;
686 	newinet->mc_loop = 1;
687 	newinet->mc_ttl = 1;
688 	newinet->mc_index = 0;
689 	newinet->mc_list = NULL;
690 
691 	if (ipv4_config.no_pmtu_disc)
692 		newinet->pmtudisc = IP_PMTUDISC_DONT;
693 	else
694 		newinet->pmtudisc = IP_PMTUDISC_WANT;
695 
696 	sk_refcnt_debug_inc(newsk);
697 
698 	if (newsk->sk_prot->init(newsk)) {
699 		sk_common_release(newsk);
700 		newsk = NULL;
701 	}
702 
703 out:
704 	return newsk;
705 }
706 
707 /* Map v4 address to mapped v6 address */
708 static void sctp_v6_addr_v4map(struct sctp_sock *sp, union sctp_addr *addr)
709 {
710 	if (sp->v4mapped && AF_INET == addr->sa.sa_family)
711 		sctp_v4_map_v6(addr);
712 }
713 
714 /* Where did this skb come from?  */
715 static int sctp_v6_skb_iif(const struct sk_buff *skb)
716 {
717 	struct inet6_skb_parm *opt = (struct inet6_skb_parm *) skb->cb;
718 	return opt->iif;
719 }
720 
721 /* Was this packet marked by Explicit Congestion Notification? */
722 static int sctp_v6_is_ce(const struct sk_buff *skb)
723 {
724 	return *((__u32 *)(ipv6_hdr(skb))) & htonl(1 << 20);
725 }
726 
727 /* Dump the v6 addr to the seq file. */
728 static void sctp_v6_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
729 {
730 	seq_printf(seq, NIP6_FMT " ", NIP6(addr->v6.sin6_addr));
731 }
732 
733 static void sctp_v6_ecn_capable(struct sock *sk)
734 {
735 	inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
736 }
737 
738 /* Initialize a PF_INET6 socket msg_name. */
739 static void sctp_inet6_msgname(char *msgname, int *addr_len)
740 {
741 	struct sockaddr_in6 *sin6;
742 
743 	sin6 = (struct sockaddr_in6 *)msgname;
744 	sin6->sin6_family = AF_INET6;
745 	sin6->sin6_flowinfo = 0;
746 	sin6->sin6_scope_id = 0; /*FIXME */
747 	*addr_len = sizeof(struct sockaddr_in6);
748 }
749 
750 /* Initialize a PF_INET msgname from a ulpevent. */
751 static void sctp_inet6_event_msgname(struct sctp_ulpevent *event,
752 				     char *msgname, int *addrlen)
753 {
754 	struct sockaddr_in6 *sin6, *sin6from;
755 
756 	if (msgname) {
757 		union sctp_addr *addr;
758 		struct sctp_association *asoc;
759 
760 		asoc = event->asoc;
761 		sctp_inet6_msgname(msgname, addrlen);
762 		sin6 = (struct sockaddr_in6 *)msgname;
763 		sin6->sin6_port = htons(asoc->peer.port);
764 		addr = &asoc->peer.primary_addr;
765 
766 		/* Note: If we go to a common v6 format, this code
767 		 * will change.
768 		 */
769 
770 		/* Map ipv4 address into v4-mapped-on-v6 address.  */
771 		if (sctp_sk(asoc->base.sk)->v4mapped &&
772 		    AF_INET == addr->sa.sa_family) {
773 			sctp_v4_map_v6((union sctp_addr *)sin6);
774 			sin6->sin6_addr.s6_addr32[3] =
775 				addr->v4.sin_addr.s_addr;
776 			return;
777 		}
778 
779 		sin6from = &asoc->peer.primary_addr.v6;
780 		ipv6_addr_copy(&sin6->sin6_addr, &sin6from->sin6_addr);
781 		if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
782 			sin6->sin6_scope_id = sin6from->sin6_scope_id;
783 	}
784 }
785 
786 /* Initialize a msg_name from an inbound skb. */
787 static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
788 				   int *addr_len)
789 {
790 	struct sctphdr *sh;
791 	struct sockaddr_in6 *sin6;
792 
793 	if (msgname) {
794 		sctp_inet6_msgname(msgname, addr_len);
795 		sin6 = (struct sockaddr_in6 *)msgname;
796 		sh = sctp_hdr(skb);
797 		sin6->sin6_port = sh->source;
798 
799 		/* Map ipv4 address into v4-mapped-on-v6 address. */
800 		if (sctp_sk(skb->sk)->v4mapped &&
801 		    ip_hdr(skb)->version == 4) {
802 			sctp_v4_map_v6((union sctp_addr *)sin6);
803 			sin6->sin6_addr.s6_addr32[3] = ip_hdr(skb)->saddr;
804 			return;
805 		}
806 
807 		/* Otherwise, just copy the v6 address. */
808 		ipv6_addr_copy(&sin6->sin6_addr, &ipv6_hdr(skb)->saddr);
809 		if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL) {
810 			struct sctp_ulpevent *ev = sctp_skb2event(skb);
811 			sin6->sin6_scope_id = ev->iif;
812 		}
813 	}
814 }
815 
816 /* Do we support this AF? */
817 static int sctp_inet6_af_supported(sa_family_t family, struct sctp_sock *sp)
818 {
819 	switch (family) {
820 	case AF_INET6:
821 		return 1;
822 	/* v4-mapped-v6 addresses */
823 	case AF_INET:
824 		if (!__ipv6_only_sock(sctp_opt2sk(sp)))
825 			return 1;
826 	default:
827 		return 0;
828 	}
829 }
830 
831 /* Address matching with wildcards allowed.  This extra level
832  * of indirection lets us choose whether a PF_INET6 should
833  * disallow any v4 addresses if we so choose.
834  */
835 static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
836 			       const union sctp_addr *addr2,
837 			       struct sctp_sock *opt)
838 {
839 	struct sctp_af *af1, *af2;
840 
841 	af1 = sctp_get_af_specific(addr1->sa.sa_family);
842 	af2 = sctp_get_af_specific(addr2->sa.sa_family);
843 
844 	if (!af1 || !af2)
845 		return 0;
846 
847 	/* If the socket is IPv6 only, v4 addrs will not match */
848 	if (__ipv6_only_sock(sctp_opt2sk(opt)) && af1 != af2)
849 		return 0;
850 
851 	/* Today, wildcard AF_INET/AF_INET6. */
852 	if (sctp_is_any(addr1) || sctp_is_any(addr2))
853 		return 1;
854 
855 	if (addr1->sa.sa_family != addr2->sa.sa_family)
856 		return 0;
857 
858 	return af1->cmp_addr(addr1, addr2);
859 }
860 
861 /* Verify that the provided sockaddr looks bindable.   Common verification,
862  * has already been taken care of.
863  */
864 static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
865 {
866 	struct sctp_af *af;
867 
868 	/* ASSERT: address family has already been verified. */
869 	if (addr->sa.sa_family != AF_INET6)
870 		af = sctp_get_af_specific(addr->sa.sa_family);
871 	else {
872 		int type = ipv6_addr_type(&addr->v6.sin6_addr);
873 		struct net_device *dev;
874 
875 		if (type & IPV6_ADDR_LINKLOCAL) {
876 			if (!addr->v6.sin6_scope_id)
877 				return 0;
878 			dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
879 			if (!dev)
880 				return 0;
881 			if (!ipv6_chk_addr(&init_net, &addr->v6.sin6_addr,
882 					   dev, 0)) {
883 				dev_put(dev);
884 				return 0;
885 			}
886 			dev_put(dev);
887 		} else if (type == IPV6_ADDR_MAPPED) {
888 			if (!opt->v4mapped)
889 				return 0;
890 		}
891 
892 		af = opt->pf->af;
893 	}
894 	return af->available(addr, opt);
895 }
896 
897 /* Verify that the provided sockaddr looks sendable.   Common verification,
898  * has already been taken care of.
899  */
900 static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
901 {
902 	struct sctp_af *af = NULL;
903 
904 	/* ASSERT: address family has already been verified. */
905 	if (addr->sa.sa_family != AF_INET6)
906 		af = sctp_get_af_specific(addr->sa.sa_family);
907 	else {
908 		int type = ipv6_addr_type(&addr->v6.sin6_addr);
909 		struct net_device *dev;
910 
911 		if (type & IPV6_ADDR_LINKLOCAL) {
912 			if (!addr->v6.sin6_scope_id)
913 				return 0;
914 			dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
915 			if (!dev)
916 				return 0;
917 			dev_put(dev);
918 		}
919 		af = opt->pf->af;
920 	}
921 
922 	return af != NULL;
923 }
924 
925 /* Fill in Supported Address Type information for INIT and INIT-ACK
926  * chunks.   Note: In the future, we may want to look at sock options
927  * to determine whether a PF_INET6 socket really wants to have IPV4
928  * addresses.
929  * Returns number of addresses supported.
930  */
931 static int sctp_inet6_supported_addrs(const struct sctp_sock *opt,
932 				      __be16 *types)
933 {
934 	types[0] = SCTP_PARAM_IPV6_ADDRESS;
935 	if (!opt || !ipv6_only_sock(sctp_opt2sk(opt))) {
936 		types[1] = SCTP_PARAM_IPV4_ADDRESS;
937 		return 2;
938 	}
939 	return 1;
940 }
941 
942 static const struct proto_ops inet6_seqpacket_ops = {
943 	.family		   = PF_INET6,
944 	.owner		   = THIS_MODULE,
945 	.release	   = inet6_release,
946 	.bind		   = inet6_bind,
947 	.connect	   = inet_dgram_connect,
948 	.socketpair	   = sock_no_socketpair,
949 	.accept		   = inet_accept,
950 	.getname	   = inet6_getname,
951 	.poll		   = sctp_poll,
952 	.ioctl		   = inet6_ioctl,
953 	.listen		   = sctp_inet_listen,
954 	.shutdown	   = inet_shutdown,
955 	.setsockopt	   = sock_common_setsockopt,
956 	.getsockopt	   = sock_common_getsockopt,
957 	.sendmsg	   = inet_sendmsg,
958 	.recvmsg	   = sock_common_recvmsg,
959 	.mmap		   = sock_no_mmap,
960 #ifdef CONFIG_COMPAT
961 	.compat_setsockopt = compat_sock_common_setsockopt,
962 	.compat_getsockopt = compat_sock_common_getsockopt,
963 #endif
964 };
965 
966 static struct inet_protosw sctpv6_seqpacket_protosw = {
967 	.type          = SOCK_SEQPACKET,
968 	.protocol      = IPPROTO_SCTP,
969 	.prot 	       = &sctpv6_prot,
970 	.ops           = &inet6_seqpacket_ops,
971 	.capability    = -1,
972 	.no_check      = 0,
973 	.flags         = SCTP_PROTOSW_FLAG
974 };
975 static struct inet_protosw sctpv6_stream_protosw = {
976 	.type          = SOCK_STREAM,
977 	.protocol      = IPPROTO_SCTP,
978 	.prot 	       = &sctpv6_prot,
979 	.ops           = &inet6_seqpacket_ops,
980 	.capability    = -1,
981 	.no_check      = 0,
982 	.flags         = SCTP_PROTOSW_FLAG,
983 };
984 
985 static int sctp6_rcv(struct sk_buff *skb)
986 {
987 	return sctp_rcv(skb) ? -1 : 0;
988 }
989 
990 static struct inet6_protocol sctpv6_protocol = {
991 	.handler      = sctp6_rcv,
992 	.err_handler  = sctp_v6_err,
993 	.flags        = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
994 };
995 
996 static struct sctp_af sctp_af_inet6 = {
997 	.sa_family	   = AF_INET6,
998 	.sctp_xmit	   = sctp_v6_xmit,
999 	.setsockopt	   = ipv6_setsockopt,
1000 	.getsockopt	   = ipv6_getsockopt,
1001 	.get_dst	   = sctp_v6_get_dst,
1002 	.get_saddr	   = sctp_v6_get_saddr,
1003 	.copy_addrlist	   = sctp_v6_copy_addrlist,
1004 	.from_skb	   = sctp_v6_from_skb,
1005 	.from_sk	   = sctp_v6_from_sk,
1006 	.to_sk_saddr	   = sctp_v6_to_sk_saddr,
1007 	.to_sk_daddr	   = sctp_v6_to_sk_daddr,
1008 	.from_addr_param   = sctp_v6_from_addr_param,
1009 	.to_addr_param	   = sctp_v6_to_addr_param,
1010 	.dst_saddr	   = sctp_v6_dst_saddr,
1011 	.cmp_addr	   = sctp_v6_cmp_addr,
1012 	.scope		   = sctp_v6_scope,
1013 	.addr_valid	   = sctp_v6_addr_valid,
1014 	.inaddr_any	   = sctp_v6_inaddr_any,
1015 	.is_any		   = sctp_v6_is_any,
1016 	.available	   = sctp_v6_available,
1017 	.skb_iif	   = sctp_v6_skb_iif,
1018 	.is_ce		   = sctp_v6_is_ce,
1019 	.seq_dump_addr	   = sctp_v6_seq_dump_addr,
1020 	.ecn_capable	   = sctp_v6_ecn_capable,
1021 	.net_header_len	   = sizeof(struct ipv6hdr),
1022 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1023 #ifdef CONFIG_COMPAT
1024 	.compat_setsockopt = compat_ipv6_setsockopt,
1025 	.compat_getsockopt = compat_ipv6_getsockopt,
1026 #endif
1027 };
1028 
1029 static struct sctp_pf sctp_pf_inet6 = {
1030 	.event_msgname = sctp_inet6_event_msgname,
1031 	.skb_msgname   = sctp_inet6_skb_msgname,
1032 	.af_supported  = sctp_inet6_af_supported,
1033 	.cmp_addr      = sctp_inet6_cmp_addr,
1034 	.bind_verify   = sctp_inet6_bind_verify,
1035 	.send_verify   = sctp_inet6_send_verify,
1036 	.supported_addrs = sctp_inet6_supported_addrs,
1037 	.create_accept_sk = sctp_v6_create_accept_sk,
1038 	.addr_v4map    = sctp_v6_addr_v4map,
1039 	.af            = &sctp_af_inet6,
1040 };
1041 
1042 /* Initialize IPv6 support and register with socket layer.  */
1043 void sctp_v6_pf_init(void)
1044 {
1045 	/* Register the SCTP specific PF_INET6 functions. */
1046 	sctp_register_pf(&sctp_pf_inet6, PF_INET6);
1047 
1048 	/* Register the SCTP specific AF_INET6 functions. */
1049 	sctp_register_af(&sctp_af_inet6);
1050 }
1051 
1052 void sctp_v6_pf_exit(void)
1053 {
1054 	list_del(&sctp_af_inet6.list);
1055 }
1056 
1057 /* Initialize IPv6 support and register with socket layer.  */
1058 int sctp_v6_protosw_init(void)
1059 {
1060 	int rc;
1061 
1062 	rc = proto_register(&sctpv6_prot, 1);
1063 	if (rc)
1064 		return rc;
1065 
1066 	/* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
1067 	inet6_register_protosw(&sctpv6_seqpacket_protosw);
1068 	inet6_register_protosw(&sctpv6_stream_protosw);
1069 
1070 	return 0;
1071 }
1072 
1073 void sctp_v6_protosw_exit(void)
1074 {
1075 	inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
1076 	inet6_unregister_protosw(&sctpv6_stream_protosw);
1077 	proto_unregister(&sctpv6_prot);
1078 }
1079 
1080 
1081 /* Register with inet6 layer. */
1082 int sctp_v6_add_protocol(void)
1083 {
1084 	/* Register notifier for inet6 address additions/deletions. */
1085 	register_inet6addr_notifier(&sctp_inet6addr_notifier);
1086 
1087 	if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
1088 		return -EAGAIN;
1089 
1090 	return 0;
1091 }
1092 
1093 /* Unregister with inet6 layer. */
1094 void sctp_v6_del_protocol(void)
1095 {
1096 	inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
1097 	unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
1098 }
1099