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Linux/net/sctp/ipv6.c

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  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, see
 25  * <http://www.gnu.org/licenses/>.
 26  *
 27  * Please send any bug reports or fixes you make to the
 28  * email address(es):
 29  *    lksctp developers <linux-sctp@vger.kernel.org>
 30  *
 31  * Written or modified by:
 32  *    Le Yanqun             <yanqun.le@nokia.com>
 33  *    Hui Huang             <hui.huang@nokia.com>
 34  *    La Monte H.P. Yarroll <piggy@acm.org>
 35  *    Sridhar Samudrala     <sri@us.ibm.com>
 36  *    Jon Grimm             <jgrimm@us.ibm.com>
 37  *    Ardelle Fan           <ardelle.fan@intel.com>
 38  *
 39  * Based on:
 40  *      linux/net/ipv6/tcp_ipv6.c
 41  */
 42 
 43 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 44 
 45 #include <linux/module.h>
 46 #include <linux/errno.h>
 47 #include <linux/types.h>
 48 #include <linux/socket.h>
 49 #include <linux/sockios.h>
 50 #include <linux/net.h>
 51 #include <linux/in.h>
 52 #include <linux/in6.h>
 53 #include <linux/netdevice.h>
 54 #include <linux/init.h>
 55 #include <linux/ipsec.h>
 56 #include <linux/slab.h>
 57 
 58 #include <linux/ipv6.h>
 59 #include <linux/icmpv6.h>
 60 #include <linux/random.h>
 61 #include <linux/seq_file.h>
 62 
 63 #include <net/protocol.h>
 64 #include <net/ndisc.h>
 65 #include <net/ip.h>
 66 #include <net/ipv6.h>
 67 #include <net/transp_v6.h>
 68 #include <net/addrconf.h>
 69 #include <net/ip6_route.h>
 70 #include <net/inet_common.h>
 71 #include <net/inet_ecn.h>
 72 #include <net/sctp/sctp.h>
 73 
 74 #include <asm/uaccess.h>
 75 
 76 static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
 77                                          union sctp_addr *s2);
 78 static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
 79                               __be16 port);
 80 static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
 81                             const union sctp_addr *addr2);
 82 
 83 /* Event handler for inet6 address addition/deletion events.
 84  * The sctp_local_addr_list needs to be protocted by a spin lock since
 85  * multiple notifiers (say IPv4 and IPv6) may be running at the same
 86  * time and thus corrupt the list.
 87  * The reader side is protected with RCU.
 88  */
 89 static int sctp_inet6addr_event(struct notifier_block *this, unsigned long ev,
 90                                 void *ptr)
 91 {
 92         struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
 93         struct sctp_sockaddr_entry *addr = NULL;
 94         struct sctp_sockaddr_entry *temp;
 95         struct net *net = dev_net(ifa->idev->dev);
 96         int found = 0;
 97 
 98         switch (ev) {
 99         case NETDEV_UP:
100                 addr = kmalloc(sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
101                 if (addr) {
102                         addr->a.v6.sin6_family = AF_INET6;
103                         addr->a.v6.sin6_port = 0;
104                         addr->a.v6.sin6_addr = ifa->addr;
105                         addr->a.v6.sin6_scope_id = ifa->idev->dev->ifindex;
106                         addr->valid = 1;
107                         spin_lock_bh(&net->sctp.local_addr_lock);
108                         list_add_tail_rcu(&addr->list, &net->sctp.local_addr_list);
109                         sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_NEW);
110                         spin_unlock_bh(&net->sctp.local_addr_lock);
111                 }
112                 break;
113         case NETDEV_DOWN:
114                 spin_lock_bh(&net->sctp.local_addr_lock);
115                 list_for_each_entry_safe(addr, temp,
116                                         &net->sctp.local_addr_list, list) {
117                         if (addr->a.sa.sa_family == AF_INET6 &&
118                                         ipv6_addr_equal(&addr->a.v6.sin6_addr,
119                                                 &ifa->addr)) {
120                                 sctp_addr_wq_mgmt(net, addr, SCTP_ADDR_DEL);
121                                 found = 1;
122                                 addr->valid = 0;
123                                 list_del_rcu(&addr->list);
124                                 break;
125                         }
126                 }
127                 spin_unlock_bh(&net->sctp.local_addr_lock);
128                 if (found)
129                         kfree_rcu(addr, rcu);
130                 break;
131         }
132 
133         return NOTIFY_DONE;
134 }
135 
136 static struct notifier_block sctp_inet6addr_notifier = {
137         .notifier_call = sctp_inet6addr_event,
138 };
139 
140 /* ICMP error handler. */
141 static void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
142                         u8 type, u8 code, int offset, __be32 info)
143 {
144         struct inet6_dev *idev;
145         struct sock *sk;
146         struct sctp_association *asoc;
147         struct sctp_transport *transport;
148         struct ipv6_pinfo *np;
149         __u16 saveip, savesctp;
150         int err;
151         struct net *net = dev_net(skb->dev);
152 
153         idev = in6_dev_get(skb->dev);
154 
155         /* Fix up skb to look at the embedded net header. */
156         saveip   = skb->network_header;
157         savesctp = skb->transport_header;
158         skb_reset_network_header(skb);
159         skb_set_transport_header(skb, offset);
160         sk = sctp_err_lookup(net, AF_INET6, skb, sctp_hdr(skb), &asoc, &transport);
161         /* Put back, the original pointers. */
162         skb->network_header   = saveip;
163         skb->transport_header = savesctp;
164         if (!sk) {
165                 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_INERRORS);
166                 goto out;
167         }
168 
169         /* Warning:  The sock lock is held.  Remember to call
170          * sctp_err_finish!
171          */
172 
173         switch (type) {
174         case ICMPV6_PKT_TOOBIG:
175                 if (ip6_sk_accept_pmtu(sk))
176                         sctp_icmp_frag_needed(sk, asoc, transport, ntohl(info));
177                 goto out_unlock;
178         case ICMPV6_PARAMPROB:
179                 if (ICMPV6_UNK_NEXTHDR == code) {
180                         sctp_icmp_proto_unreachable(sk, asoc, transport);
181                         goto out_unlock;
182                 }
183                 break;
184         case NDISC_REDIRECT:
185                 sctp_icmp_redirect(sk, transport, skb);
186                 goto out_unlock;
187         default:
188                 break;
189         }
190 
191         np = inet6_sk(sk);
192         icmpv6_err_convert(type, code, &err);
193         if (!sock_owned_by_user(sk) && np->recverr) {
194                 sk->sk_err = err;
195                 sk->sk_error_report(sk);
196         } else {  /* Only an error on timeout */
197                 sk->sk_err_soft = err;
198         }
199 
200 out_unlock:
201         sctp_err_finish(sk, asoc);
202 out:
203         if (likely(idev != NULL))
204                 in6_dev_put(idev);
205 }
206 
207 static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)
208 {
209         struct sock *sk = skb->sk;
210         struct ipv6_pinfo *np = inet6_sk(sk);
211         struct flowi6 *fl6 = &transport->fl.u.ip6;
212         int res;
213 
214         pr_debug("%s: skb:%p, len:%d, src:%pI6 dst:%pI6\n", __func__, skb,
215                  skb->len, &fl6->saddr, &fl6->daddr);
216 
217         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
218 
219         if (!(transport->param_flags & SPP_PMTUD_ENABLE))
220                 skb->ignore_df = 1;
221 
222         SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
223 
224         rcu_read_lock();
225         res = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt), np->tclass);
226         rcu_read_unlock();
227         return res;
228 }
229 
230 /* Returns the dst cache entry for the given source and destination ip
231  * addresses.
232  */
233 static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
234                             struct flowi *fl, struct sock *sk)
235 {
236         struct sctp_association *asoc = t->asoc;
237         struct dst_entry *dst = NULL;
238         struct flowi6 *fl6 = &fl->u.ip6;
239         struct sctp_bind_addr *bp;
240         struct ipv6_pinfo *np = inet6_sk(sk);
241         struct sctp_sockaddr_entry *laddr;
242         union sctp_addr *baddr = NULL;
243         union sctp_addr *daddr = &t->ipaddr;
244         union sctp_addr dst_saddr;
245         struct in6_addr *final_p, final;
246         __u8 matchlen = 0;
247         __u8 bmatchlen;
248         sctp_scope_t scope;
249 
250         memset(fl6, 0, sizeof(struct flowi6));
251         fl6->daddr = daddr->v6.sin6_addr;
252         fl6->fl6_dport = daddr->v6.sin6_port;
253         fl6->flowi6_proto = IPPROTO_SCTP;
254         if (ipv6_addr_type(&daddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
255                 fl6->flowi6_oif = daddr->v6.sin6_scope_id;
256 
257         pr_debug("%s: dst=%pI6 ", __func__, &fl6->daddr);
258 
259         if (asoc)
260                 fl6->fl6_sport = htons(asoc->base.bind_addr.port);
261 
262         if (saddr) {
263                 fl6->saddr = saddr->v6.sin6_addr;
264                 fl6->fl6_sport = saddr->v6.sin6_port;
265 
266                 pr_debug("src=%pI6 - ", &fl6->saddr);
267         }
268 
269         rcu_read_lock();
270         final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
271         rcu_read_unlock();
272 
273         dst = ip6_dst_lookup_flow(sk, fl6, final_p);
274         if (!asoc || saddr)
275                 goto out;
276 
277         bp = &asoc->base.bind_addr;
278         scope = sctp_scope(daddr);
279         /* ip6_dst_lookup has filled in the fl6->saddr for us.  Check
280          * to see if we can use it.
281          */
282         if (!IS_ERR(dst)) {
283                 /* Walk through the bind address list and look for a bind
284                  * address that matches the source address of the returned dst.
285                  */
286                 sctp_v6_to_addr(&dst_saddr, &fl6->saddr, htons(bp->port));
287                 rcu_read_lock();
288                 list_for_each_entry_rcu(laddr, &bp->address_list, list) {
289                         if (!laddr->valid || laddr->state == SCTP_ADDR_DEL ||
290                             (laddr->state != SCTP_ADDR_SRC &&
291                              !asoc->src_out_of_asoc_ok))
292                                 continue;
293 
294                         /* Do not compare against v4 addrs */
295                         if ((laddr->a.sa.sa_family == AF_INET6) &&
296                             (sctp_v6_cmp_addr(&dst_saddr, &laddr->a))) {
297                                 rcu_read_unlock();
298                                 goto out;
299                         }
300                 }
301                 rcu_read_unlock();
302                 /* None of the bound addresses match the source address of the
303                  * dst. So release it.
304                  */
305                 dst_release(dst);
306                 dst = NULL;
307         }
308 
309         /* Walk through the bind address list and try to get the
310          * best source address for a given destination.
311          */
312         rcu_read_lock();
313         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
314                 if (!laddr->valid)
315                         continue;
316                 if ((laddr->state == SCTP_ADDR_SRC) &&
317                     (laddr->a.sa.sa_family == AF_INET6) &&
318                     (scope <= sctp_scope(&laddr->a))) {
319                         bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
320                         if (!baddr || (matchlen < bmatchlen)) {
321                                 baddr = &laddr->a;
322                                 matchlen = bmatchlen;
323                         }
324                 }
325         }
326         if (baddr) {
327                 fl6->saddr = baddr->v6.sin6_addr;
328                 fl6->fl6_sport = baddr->v6.sin6_port;
329                 final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
330                 dst = ip6_dst_lookup_flow(sk, fl6, final_p);
331         }
332         rcu_read_unlock();
333 
334 out:
335         if (!IS_ERR_OR_NULL(dst)) {
336                 struct rt6_info *rt;
337 
338                 rt = (struct rt6_info *)dst;
339                 t->dst = dst;
340                 t->dst_cookie = rt6_get_cookie(rt);
341                 pr_debug("rt6_dst:%pI6/%d rt6_src:%pI6\n",
342                          &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
343                          &fl6->saddr);
344         } else {
345                 t->dst = NULL;
346 
347                 pr_debug("no route\n");
348         }
349 }
350 
351 /* Returns the number of consecutive initial bits that match in the 2 ipv6
352  * addresses.
353  */
354 static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
355                                          union sctp_addr *s2)
356 {
357         return ipv6_addr_diff(&s1->v6.sin6_addr, &s2->v6.sin6_addr);
358 }
359 
360 /* Fills in the source address(saddr) based on the destination address(daddr)
361  * and asoc's bind address list.
362  */
363 static void sctp_v6_get_saddr(struct sctp_sock *sk,
364                               struct sctp_transport *t,
365                               struct flowi *fl)
366 {
367         struct flowi6 *fl6 = &fl->u.ip6;
368         union sctp_addr *saddr = &t->saddr;
369 
370         pr_debug("%s: asoc:%p dst:%p\n", __func__, t->asoc, t->dst);
371 
372         if (t->dst) {
373                 saddr->v6.sin6_family = AF_INET6;
374                 saddr->v6.sin6_addr = fl6->saddr;
375         }
376 }
377 
378 /* Make a copy of all potential local addresses. */
379 static void sctp_v6_copy_addrlist(struct list_head *addrlist,
380                                   struct net_device *dev)
381 {
382         struct inet6_dev *in6_dev;
383         struct inet6_ifaddr *ifp;
384         struct sctp_sockaddr_entry *addr;
385 
386         rcu_read_lock();
387         if ((in6_dev = __in6_dev_get(dev)) == NULL) {
388                 rcu_read_unlock();
389                 return;
390         }
391 
392         read_lock_bh(&in6_dev->lock);
393         list_for_each_entry(ifp, &in6_dev->addr_list, if_list) {
394                 /* Add the address to the local list.  */
395                 addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
396                 if (addr) {
397                         addr->a.v6.sin6_family = AF_INET6;
398                         addr->a.v6.sin6_port = 0;
399                         addr->a.v6.sin6_addr = ifp->addr;
400                         addr->a.v6.sin6_scope_id = dev->ifindex;
401                         addr->valid = 1;
402                         INIT_LIST_HEAD(&addr->list);
403                         list_add_tail(&addr->list, addrlist);
404                 }
405         }
406 
407         read_unlock_bh(&in6_dev->lock);
408         rcu_read_unlock();
409 }
410 
411 /* Initialize a sockaddr_storage from in incoming skb. */
412 static void sctp_v6_from_skb(union sctp_addr *addr, struct sk_buff *skb,
413                              int is_saddr)
414 {
415         __be16 *port;
416         struct sctphdr *sh;
417 
418         port = &addr->v6.sin6_port;
419         addr->v6.sin6_family = AF_INET6;
420         addr->v6.sin6_flowinfo = 0; /* FIXME */
421         addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;
422 
423         /* Always called on head skb, so this is safe */
424         sh = sctp_hdr(skb);
425         if (is_saddr) {
426                 *port  = sh->source;
427                 addr->v6.sin6_addr = ipv6_hdr(skb)->saddr;
428         } else {
429                 *port = sh->dest;
430                 addr->v6.sin6_addr = ipv6_hdr(skb)->daddr;
431         }
432 }
433 
434 /* Initialize an sctp_addr from a socket. */
435 static void sctp_v6_from_sk(union sctp_addr *addr, struct sock *sk)
436 {
437         addr->v6.sin6_family = AF_INET6;
438         addr->v6.sin6_port = 0;
439         addr->v6.sin6_addr = sk->sk_v6_rcv_saddr;
440 }
441 
442 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
443 static void sctp_v6_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
444 {
445         if (addr->sa.sa_family == AF_INET) {
446                 sk->sk_v6_rcv_saddr.s6_addr32[0] = 0;
447                 sk->sk_v6_rcv_saddr.s6_addr32[1] = 0;
448                 sk->sk_v6_rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
449                 sk->sk_v6_rcv_saddr.s6_addr32[3] =
450                         addr->v4.sin_addr.s_addr;
451         } else {
452                 sk->sk_v6_rcv_saddr = addr->v6.sin6_addr;
453         }
454 }
455 
456 /* Initialize sk->sk_daddr from sctp_addr. */
457 static void sctp_v6_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
458 {
459         if (addr->sa.sa_family == AF_INET) {
460                 sk->sk_v6_daddr.s6_addr32[0] = 0;
461                 sk->sk_v6_daddr.s6_addr32[1] = 0;
462                 sk->sk_v6_daddr.s6_addr32[2] = htonl(0x0000ffff);
463                 sk->sk_v6_daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
464         } else {
465                 sk->sk_v6_daddr = addr->v6.sin6_addr;
466         }
467 }
468 
469 /* Initialize a sctp_addr from an address parameter. */
470 static void sctp_v6_from_addr_param(union sctp_addr *addr,
471                                     union sctp_addr_param *param,
472                                     __be16 port, int iif)
473 {
474         addr->v6.sin6_family = AF_INET6;
475         addr->v6.sin6_port = port;
476         addr->v6.sin6_flowinfo = 0; /* BUG */
477         addr->v6.sin6_addr = param->v6.addr;
478         addr->v6.sin6_scope_id = iif;
479 }
480 
481 /* Initialize an address parameter from a sctp_addr and return the length
482  * of the address parameter.
483  */
484 static int sctp_v6_to_addr_param(const union sctp_addr *addr,
485                                  union sctp_addr_param *param)
486 {
487         int length = sizeof(sctp_ipv6addr_param_t);
488 
489         param->v6.param_hdr.type = SCTP_PARAM_IPV6_ADDRESS;
490         param->v6.param_hdr.length = htons(length);
491         param->v6.addr = addr->v6.sin6_addr;
492 
493         return length;
494 }
495 
496 /* Initialize a sctp_addr from struct in6_addr. */
497 static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
498                               __be16 port)
499 {
500         addr->sa.sa_family = AF_INET6;
501         addr->v6.sin6_port = port;
502         addr->v6.sin6_addr = *saddr;
503 }
504 
505 /* Compare addresses exactly.
506  * v4-mapped-v6 is also in consideration.
507  */
508 static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
509                             const union sctp_addr *addr2)
510 {
511         if (addr1->sa.sa_family != addr2->sa.sa_family) {
512                 if (addr1->sa.sa_family == AF_INET &&
513                     addr2->sa.sa_family == AF_INET6 &&
514                     ipv6_addr_v4mapped(&addr2->v6.sin6_addr)) {
515                         if (addr2->v6.sin6_port == addr1->v4.sin_port &&
516                             addr2->v6.sin6_addr.s6_addr32[3] ==
517                             addr1->v4.sin_addr.s_addr)
518                                 return 1;
519                 }
520                 if (addr2->sa.sa_family == AF_INET &&
521                     addr1->sa.sa_family == AF_INET6 &&
522                     ipv6_addr_v4mapped(&addr1->v6.sin6_addr)) {
523                         if (addr1->v6.sin6_port == addr2->v4.sin_port &&
524                             addr1->v6.sin6_addr.s6_addr32[3] ==
525                             addr2->v4.sin_addr.s_addr)
526                                 return 1;
527                 }
528                 return 0;
529         }
530         if (addr1->v6.sin6_port != addr2->v6.sin6_port)
531                 return 0;
532         if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
533                 return 0;
534         /* If this is a linklocal address, compare the scope_id. */
535         if (ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
536                 if (addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
537                     (addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)) {
538                         return 0;
539                 }
540         }
541 
542         return 1;
543 }
544 
545 /* Initialize addr struct to INADDR_ANY. */
546 static void sctp_v6_inaddr_any(union sctp_addr *addr, __be16 port)
547 {
548         memset(addr, 0x00, sizeof(union sctp_addr));
549         addr->v6.sin6_family = AF_INET6;
550         addr->v6.sin6_port = port;
551 }
552 
553 /* Is this a wildcard address? */
554 static int sctp_v6_is_any(const union sctp_addr *addr)
555 {
556         return ipv6_addr_any(&addr->v6.sin6_addr);
557 }
558 
559 /* Should this be available for binding?   */
560 static int sctp_v6_available(union sctp_addr *addr, struct sctp_sock *sp)
561 {
562         int type;
563         struct net *net = sock_net(&sp->inet.sk);
564         const struct in6_addr *in6 = (const struct in6_addr *)&addr->v6.sin6_addr;
565 
566         type = ipv6_addr_type(in6);
567         if (IPV6_ADDR_ANY == type)
568                 return 1;
569         if (type == IPV6_ADDR_MAPPED) {
570                 if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
571                         return 0;
572                 sctp_v6_map_v4(addr);
573                 return sctp_get_af_specific(AF_INET)->available(addr, sp);
574         }
575         if (!(type & IPV6_ADDR_UNICAST))
576                 return 0;
577 
578         return sp->inet.freebind || net->ipv6.sysctl.ip_nonlocal_bind ||
579                 ipv6_chk_addr(net, in6, NULL, 0);
580 }
581 
582 /* This function checks if the address is a valid address to be used for
583  * SCTP.
584  *
585  * Output:
586  * Return 0 - If the address is a non-unicast or an illegal address.
587  * Return 1 - If the address is a unicast.
588  */
589 static int sctp_v6_addr_valid(union sctp_addr *addr,
590                               struct sctp_sock *sp,
591                               const struct sk_buff *skb)
592 {
593         int ret = ipv6_addr_type(&addr->v6.sin6_addr);
594 
595         /* Support v4-mapped-v6 address. */
596         if (ret == IPV6_ADDR_MAPPED) {
597                 /* Note: This routine is used in input, so v4-mapped-v6
598                  * are disallowed here when there is no sctp_sock.
599                  */
600                 if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
601                         return 0;
602                 sctp_v6_map_v4(addr);
603                 return sctp_get_af_specific(AF_INET)->addr_valid(addr, sp, skb);
604         }
605 
606         /* Is this a non-unicast address */
607         if (!(ret & IPV6_ADDR_UNICAST))
608                 return 0;
609 
610         return 1;
611 }
612 
613 /* What is the scope of 'addr'?  */
614 static sctp_scope_t sctp_v6_scope(union sctp_addr *addr)
615 {
616         int v6scope;
617         sctp_scope_t retval;
618 
619         /* The IPv6 scope is really a set of bit fields.
620          * See IFA_* in <net/if_inet6.h>.  Map to a generic SCTP scope.
621          */
622 
623         v6scope = ipv6_addr_scope(&addr->v6.sin6_addr);
624         switch (v6scope) {
625         case IFA_HOST:
626                 retval = SCTP_SCOPE_LOOPBACK;
627                 break;
628         case IFA_LINK:
629                 retval = SCTP_SCOPE_LINK;
630                 break;
631         case IFA_SITE:
632                 retval = SCTP_SCOPE_PRIVATE;
633                 break;
634         default:
635                 retval = SCTP_SCOPE_GLOBAL;
636                 break;
637         }
638 
639         return retval;
640 }
641 
642 /* Create and initialize a new sk for the socket to be returned by accept(). */
643 static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
644                                              struct sctp_association *asoc)
645 {
646         struct sock *newsk;
647         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
648         struct sctp6_sock *newsctp6sk;
649         struct ipv6_txoptions *opt;
650 
651         newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot, 0);
652         if (!newsk)
653                 goto out;
654 
655         sock_init_data(NULL, newsk);
656 
657         sctp_copy_sock(newsk, sk, asoc);
658         sock_reset_flag(sk, SOCK_ZAPPED);
659 
660         newsctp6sk = (struct sctp6_sock *)newsk;
661         inet_sk(newsk)->pinet6 = &newsctp6sk->inet6;
662 
663         sctp_sk(newsk)->v4mapped = sctp_sk(sk)->v4mapped;
664 
665         newnp = inet6_sk(newsk);
666 
667         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
668 
669         rcu_read_lock();
670         opt = rcu_dereference(np->opt);
671         if (opt)
672                 opt = ipv6_dup_options(newsk, opt);
673         RCU_INIT_POINTER(newnp->opt, opt);
674         rcu_read_unlock();
675 
676         /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
677          * and getpeername().
678          */
679         sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);
680 
681         newsk->sk_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
682 
683         sk_refcnt_debug_inc(newsk);
684 
685         if (newsk->sk_prot->init(newsk)) {
686                 sk_common_release(newsk);
687                 newsk = NULL;
688         }
689 
690 out:
691         return newsk;
692 }
693 
694 /* Format a sockaddr for return to user space. This makes sure the return is
695  * AF_INET or AF_INET6 depending on the SCTP_I_WANT_MAPPED_V4_ADDR option.
696  */
697 static int sctp_v6_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
698 {
699         if (sp->v4mapped) {
700                 if (addr->sa.sa_family == AF_INET)
701                         sctp_v4_map_v6(addr);
702         } else {
703                 if (addr->sa.sa_family == AF_INET6 &&
704                     ipv6_addr_v4mapped(&addr->v6.sin6_addr))
705                         sctp_v6_map_v4(addr);
706         }
707 
708         if (addr->sa.sa_family == AF_INET)
709                 return sizeof(struct sockaddr_in);
710         return sizeof(struct sockaddr_in6);
711 }
712 
713 /* Where did this skb come from?  */
714 static int sctp_v6_skb_iif(const struct sk_buff *skb)
715 {
716         return IP6CB(skb)->iif;
717 }
718 
719 /* Was this packet marked by Explicit Congestion Notification? */
720 static int sctp_v6_is_ce(const struct sk_buff *skb)
721 {
722         return *((__u32 *)(ipv6_hdr(skb))) & htonl(1 << 20);
723 }
724 
725 /* Dump the v6 addr to the seq file. */
726 static void sctp_v6_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
727 {
728         seq_printf(seq, "%pI6 ", &addr->v6.sin6_addr);
729 }
730 
731 static void sctp_v6_ecn_capable(struct sock *sk)
732 {
733         inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
734 }
735 
736 /* Initialize a PF_INET msgname from a ulpevent. */
737 static void sctp_inet6_event_msgname(struct sctp_ulpevent *event,
738                                      char *msgname, int *addrlen)
739 {
740         union sctp_addr *addr;
741         struct sctp_association *asoc;
742         union sctp_addr *paddr;
743 
744         if (!msgname)
745                 return;
746 
747         addr = (union sctp_addr *)msgname;
748         asoc = event->asoc;
749         paddr = &asoc->peer.primary_addr;
750 
751         if (paddr->sa.sa_family == AF_INET) {
752                 addr->v4.sin_family = AF_INET;
753                 addr->v4.sin_port = htons(asoc->peer.port);
754                 addr->v4.sin_addr = paddr->v4.sin_addr;
755         } else {
756                 addr->v6.sin6_family = AF_INET6;
757                 addr->v6.sin6_flowinfo = 0;
758                 if (ipv6_addr_type(&paddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
759                         addr->v6.sin6_scope_id = paddr->v6.sin6_scope_id;
760                 else
761                         addr->v6.sin6_scope_id = 0;
762                 addr->v6.sin6_port = htons(asoc->peer.port);
763                 addr->v6.sin6_addr = paddr->v6.sin6_addr;
764         }
765 
766         *addrlen = sctp_v6_addr_to_user(sctp_sk(asoc->base.sk), addr);
767 }
768 
769 /* Initialize a msg_name from an inbound skb. */
770 static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
771                                    int *addr_len)
772 {
773         union sctp_addr *addr;
774         struct sctphdr *sh;
775 
776         if (!msgname)
777                 return;
778 
779         addr = (union sctp_addr *)msgname;
780         sh = sctp_hdr(skb);
781 
782         if (ip_hdr(skb)->version == 4) {
783                 addr->v4.sin_family = AF_INET;
784                 addr->v4.sin_port = sh->source;
785                 addr->v4.sin_addr.s_addr = ip_hdr(skb)->saddr;
786         } else {
787                 addr->v6.sin6_family = AF_INET6;
788                 addr->v6.sin6_flowinfo = 0;
789                 addr->v6.sin6_port = sh->source;
790                 addr->v6.sin6_addr = ipv6_hdr(skb)->saddr;
791                 if (ipv6_addr_type(&addr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
792                         addr->v6.sin6_scope_id = sctp_v6_skb_iif(skb);
793                 }
794         }
795 
796         *addr_len = sctp_v6_addr_to_user(sctp_sk(skb->sk), addr);
797 }
798 
799 /* Do we support this AF? */
800 static int sctp_inet6_af_supported(sa_family_t family, struct sctp_sock *sp)
801 {
802         switch (family) {
803         case AF_INET6:
804                 return 1;
805         /* v4-mapped-v6 addresses */
806         case AF_INET:
807                 if (!__ipv6_only_sock(sctp_opt2sk(sp)))
808                         return 1;
809         default:
810                 return 0;
811         }
812 }
813 
814 /* Address matching with wildcards allowed.  This extra level
815  * of indirection lets us choose whether a PF_INET6 should
816  * disallow any v4 addresses if we so choose.
817  */
818 static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
819                                const union sctp_addr *addr2,
820                                struct sctp_sock *opt)
821 {
822         struct sctp_af *af1, *af2;
823         struct sock *sk = sctp_opt2sk(opt);
824 
825         af1 = sctp_get_af_specific(addr1->sa.sa_family);
826         af2 = sctp_get_af_specific(addr2->sa.sa_family);
827 
828         if (!af1 || !af2)
829                 return 0;
830 
831         /* If the socket is IPv6 only, v4 addrs will not match */
832         if (__ipv6_only_sock(sk) && af1 != af2)
833                 return 0;
834 
835         /* Today, wildcard AF_INET/AF_INET6. */
836         if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
837                 return 1;
838 
839         if (addr1->sa.sa_family != addr2->sa.sa_family)
840                 return 0;
841 
842         return af1->cmp_addr(addr1, addr2);
843 }
844 
845 /* Verify that the provided sockaddr looks bindable.   Common verification,
846  * has already been taken care of.
847  */
848 static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
849 {
850         struct sctp_af *af;
851 
852         /* ASSERT: address family has already been verified. */
853         if (addr->sa.sa_family != AF_INET6)
854                 af = sctp_get_af_specific(addr->sa.sa_family);
855         else {
856                 int type = ipv6_addr_type(&addr->v6.sin6_addr);
857                 struct net_device *dev;
858 
859                 if (type & IPV6_ADDR_LINKLOCAL) {
860                         struct net *net;
861                         if (!addr->v6.sin6_scope_id)
862                                 return 0;
863                         net = sock_net(&opt->inet.sk);
864                         rcu_read_lock();
865                         dev = dev_get_by_index_rcu(net, addr->v6.sin6_scope_id);
866                         if (!dev ||
867                             !ipv6_chk_addr(net, &addr->v6.sin6_addr, dev, 0)) {
868                                 rcu_read_unlock();
869                                 return 0;
870                         }
871                         rcu_read_unlock();
872                 }
873 
874                 af = opt->pf->af;
875         }
876         return af->available(addr, opt);
877 }
878 
879 /* Verify that the provided sockaddr looks sendable.   Common verification,
880  * has already been taken care of.
881  */
882 static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
883 {
884         struct sctp_af *af = NULL;
885 
886         /* ASSERT: address family has already been verified. */
887         if (addr->sa.sa_family != AF_INET6)
888                 af = sctp_get_af_specific(addr->sa.sa_family);
889         else {
890                 int type = ipv6_addr_type(&addr->v6.sin6_addr);
891                 struct net_device *dev;
892 
893                 if (type & IPV6_ADDR_LINKLOCAL) {
894                         if (!addr->v6.sin6_scope_id)
895                                 return 0;
896                         rcu_read_lock();
897                         dev = dev_get_by_index_rcu(sock_net(&opt->inet.sk),
898                                                    addr->v6.sin6_scope_id);
899                         rcu_read_unlock();
900                         if (!dev)
901                                 return 0;
902                 }
903                 af = opt->pf->af;
904         }
905 
906         return af != NULL;
907 }
908 
909 /* Fill in Supported Address Type information for INIT and INIT-ACK
910  * chunks.   Note: In the future, we may want to look at sock options
911  * to determine whether a PF_INET6 socket really wants to have IPV4
912  * addresses.
913  * Returns number of addresses supported.
914  */
915 static int sctp_inet6_supported_addrs(const struct sctp_sock *opt,
916                                       __be16 *types)
917 {
918         types[0] = SCTP_PARAM_IPV6_ADDRESS;
919         if (!opt || !ipv6_only_sock(sctp_opt2sk(opt))) {
920                 types[1] = SCTP_PARAM_IPV4_ADDRESS;
921                 return 2;
922         }
923         return 1;
924 }
925 
926 /* Handle SCTP_I_WANT_MAPPED_V4_ADDR for getpeername() and getsockname() */
927 static int sctp_getname(struct socket *sock, struct sockaddr *uaddr,
928                         int *uaddr_len, int peer)
929 {
930         int rc;
931 
932         rc = inet6_getname(sock, uaddr, uaddr_len, peer);
933 
934         if (rc != 0)
935                 return rc;
936 
937         *uaddr_len = sctp_v6_addr_to_user(sctp_sk(sock->sk),
938                                           (union sctp_addr *)uaddr);
939 
940         return rc;
941 }
942 
943 static const struct proto_ops inet6_seqpacket_ops = {
944         .family            = PF_INET6,
945         .owner             = THIS_MODULE,
946         .release           = inet6_release,
947         .bind              = inet6_bind,
948         .connect           = inet_dgram_connect,
949         .socketpair        = sock_no_socketpair,
950         .accept            = inet_accept,
951         .getname           = sctp_getname,
952         .poll              = sctp_poll,
953         .ioctl             = inet6_ioctl,
954         .listen            = sctp_inet_listen,
955         .shutdown          = inet_shutdown,
956         .setsockopt        = sock_common_setsockopt,
957         .getsockopt        = sock_common_getsockopt,
958         .sendmsg           = inet_sendmsg,
959         .recvmsg           = inet_recvmsg,
960         .mmap              = sock_no_mmap,
961 #ifdef CONFIG_COMPAT
962         .compat_setsockopt = compat_sock_common_setsockopt,
963         .compat_getsockopt = compat_sock_common_getsockopt,
964 #endif
965 };
966 
967 static struct inet_protosw sctpv6_seqpacket_protosw = {
968         .type          = SOCK_SEQPACKET,
969         .protocol      = IPPROTO_SCTP,
970         .prot          = &sctpv6_prot,
971         .ops           = &inet6_seqpacket_ops,
972         .flags         = SCTP_PROTOSW_FLAG
973 };
974 static struct inet_protosw sctpv6_stream_protosw = {
975         .type          = SOCK_STREAM,
976         .protocol      = IPPROTO_SCTP,
977         .prot          = &sctpv6_prot,
978         .ops           = &inet6_seqpacket_ops,
979         .flags         = SCTP_PROTOSW_FLAG,
980 };
981 
982 static int sctp6_rcv(struct sk_buff *skb)
983 {
984         return sctp_rcv(skb) ? -1 : 0;
985 }
986 
987 static const struct inet6_protocol sctpv6_protocol = {
988         .handler      = sctp6_rcv,
989         .err_handler  = sctp_v6_err,
990         .flags        = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
991 };
992 
993 static struct sctp_af sctp_af_inet6 = {
994         .sa_family         = AF_INET6,
995         .sctp_xmit         = sctp_v6_xmit,
996         .setsockopt        = ipv6_setsockopt,
997         .getsockopt        = ipv6_getsockopt,
998         .get_dst           = sctp_v6_get_dst,
999         .get_saddr         = sctp_v6_get_saddr,
1000         .copy_addrlist     = sctp_v6_copy_addrlist,
1001         .from_skb          = sctp_v6_from_skb,
1002         .from_sk           = sctp_v6_from_sk,
1003         .from_addr_param   = sctp_v6_from_addr_param,
1004         .to_addr_param     = sctp_v6_to_addr_param,
1005         .cmp_addr          = sctp_v6_cmp_addr,
1006         .scope             = sctp_v6_scope,
1007         .addr_valid        = sctp_v6_addr_valid,
1008         .inaddr_any        = sctp_v6_inaddr_any,
1009         .is_any            = sctp_v6_is_any,
1010         .available         = sctp_v6_available,
1011         .skb_iif           = sctp_v6_skb_iif,
1012         .is_ce             = sctp_v6_is_ce,
1013         .seq_dump_addr     = sctp_v6_seq_dump_addr,
1014         .ecn_capable       = sctp_v6_ecn_capable,
1015         .net_header_len    = sizeof(struct ipv6hdr),
1016         .sockaddr_len      = sizeof(struct sockaddr_in6),
1017 #ifdef CONFIG_COMPAT
1018         .compat_setsockopt = compat_ipv6_setsockopt,
1019         .compat_getsockopt = compat_ipv6_getsockopt,
1020 #endif
1021 };
1022 
1023 static struct sctp_pf sctp_pf_inet6 = {
1024         .event_msgname = sctp_inet6_event_msgname,
1025         .skb_msgname   = sctp_inet6_skb_msgname,
1026         .af_supported  = sctp_inet6_af_supported,
1027         .cmp_addr      = sctp_inet6_cmp_addr,
1028         .bind_verify   = sctp_inet6_bind_verify,
1029         .send_verify   = sctp_inet6_send_verify,
1030         .supported_addrs = sctp_inet6_supported_addrs,
1031         .create_accept_sk = sctp_v6_create_accept_sk,
1032         .addr_to_user  = sctp_v6_addr_to_user,
1033         .to_sk_saddr   = sctp_v6_to_sk_saddr,
1034         .to_sk_daddr   = sctp_v6_to_sk_daddr,
1035         .af            = &sctp_af_inet6,
1036 };
1037 
1038 /* Initialize IPv6 support and register with socket layer.  */
1039 void sctp_v6_pf_init(void)
1040 {
1041         /* Register the SCTP specific PF_INET6 functions. */
1042         sctp_register_pf(&sctp_pf_inet6, PF_INET6);
1043 
1044         /* Register the SCTP specific AF_INET6 functions. */
1045         sctp_register_af(&sctp_af_inet6);
1046 }
1047 
1048 void sctp_v6_pf_exit(void)
1049 {
1050         list_del(&sctp_af_inet6.list);
1051 }
1052 
1053 /* Initialize IPv6 support and register with socket layer.  */
1054 int sctp_v6_protosw_init(void)
1055 {
1056         int rc;
1057 
1058         rc = proto_register(&sctpv6_prot, 1);
1059         if (rc)
1060                 return rc;
1061 
1062         /* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
1063         inet6_register_protosw(&sctpv6_seqpacket_protosw);
1064         inet6_register_protosw(&sctpv6_stream_protosw);
1065 
1066         return 0;
1067 }
1068 
1069 void sctp_v6_protosw_exit(void)
1070 {
1071         inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
1072         inet6_unregister_protosw(&sctpv6_stream_protosw);
1073         proto_unregister(&sctpv6_prot);
1074 }
1075 
1076 
1077 /* Register with inet6 layer. */
1078 int sctp_v6_add_protocol(void)
1079 {
1080         /* Register notifier for inet6 address additions/deletions. */
1081         register_inet6addr_notifier(&sctp_inet6addr_notifier);
1082 
1083         if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
1084                 return -EAGAIN;
1085 
1086         return 0;
1087 }
1088 
1089 /* Unregister with inet6 layer. */
1090 void sctp_v6_del_protocol(void)
1091 {
1092         inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
1093         unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
1094 }
1095 

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