net/sctp/ipv6.c

   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_BH(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                 sctp_icmp_frag_needed(sk, asoc, transport, ntohl(info));
 176                 goto out_unlock;
 177         case ICMPV6_PARAMPROB:
 178                 if (ICMPV6_UNK_NEXTHDR == code) {
 179                         sctp_icmp_proto_unreachable(sk, asoc, transport);
 180                         goto out_unlock;
 181                 }
 182                 break;
 183         case NDISC_REDIRECT:
 184                 sctp_icmp_redirect(sk, transport, skb);
 185                 goto out_unlock;
 186         default:
 187                 break;
 188         }
 189
 190         np = inet6_sk(sk);
 191         icmpv6_err_convert(type, code, &err);
 192         if (!sock_owned_by_user(sk) && np->recverr) {
 193                 sk->sk_err = err;
 194                 sk->sk_error_report(sk);
 195         } else {  /* Only an error on timeout */
 196                 sk->sk_err_soft = err;
 197         }
 198
 199 out_unlock:
 200         sctp_err_finish(sk, asoc);
 201 out:
 202         if (likely(idev != NULL))
 203                 in6_dev_put(idev);
 204 }
 205
 206 static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)
 207 {
 208         struct sock *sk = skb->sk;
 209         struct ipv6_pinfo *np = inet6_sk(sk);
 210         struct flowi6 *fl6 = &transport->fl.u.ip6;
 211
 212         pr_debug("%s: skb:%p, len:%d, src:%pI6 dst:%pI6\n", __func__, skb,
 213                  skb->len, &fl6->saddr, &fl6->daddr);
 214
 215         IP6_ECN_flow_xmit(sk, fl6->flowlabel);
 216
 217         if (!(transport->param_flags & SPP_PMTUD_ENABLE))
 218                 skb->local_df = 1;
 219
 220         SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
 221
 222         return ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
 223 }
 224
 225 /* Returns the dst cache entry for the given source and destination ip
 226  * addresses.
 227  */
 228 static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
 229                             struct flowi *fl, struct sock *sk)
 230 {
 231         struct sctp_association *asoc = t->asoc;
 232         struct dst_entry *dst = NULL;
 233         struct flowi6 *fl6 = &fl->u.ip6;
 234         struct sctp_bind_addr *bp;
 235         struct ipv6_pinfo *np = inet6_sk(sk);
 236         struct sctp_sockaddr_entry *laddr;
 237         union sctp_addr *baddr = NULL;
 238         union sctp_addr *daddr = &t->ipaddr;
 239         union sctp_addr dst_saddr;
 240         struct in6_addr *final_p, final;
 241         __u8 matchlen = 0;
 242         __u8 bmatchlen;
 243         sctp_scope_t scope;
 244
 245         memset(fl6, 0, sizeof(struct flowi6));
 246         fl6->daddr = daddr->v6.sin6_addr;
 247         fl6->fl6_dport = daddr->v6.sin6_port;
 248         fl6->flowi6_proto = IPPROTO_SCTP;
 249         if (ipv6_addr_type(&daddr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
 250                 fl6->flowi6_oif = daddr->v6.sin6_scope_id;
 251
 252         pr_debug("%s: dst=%pI6 ", __func__, &fl6->daddr);
 253
 254         if (asoc)
 255                 fl6->fl6_sport = htons(asoc->base.bind_addr.port);
 256
 257         if (saddr) {
 258                 fl6->saddr = saddr->v6.sin6_addr;
 259                 fl6->fl6_sport = saddr->v6.sin6_port;
 260
 261                 pr_debug("src=%pI6 - ", &fl6->saddr);
 262         }
 263
 264         final_p = fl6_update_dst(fl6, np->opt, &final);
 265         dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
 266         if (!asoc || saddr)
 267                 goto out;
 268
 269         bp = &asoc->base.bind_addr;
 270         scope = sctp_scope(daddr);
 271         /* ip6_dst_lookup has filled in the fl6->saddr for us.  Check
 272          * to see if we can use it.
 273          */
 274         if (!IS_ERR(dst)) {
 275                 /* Walk through the bind address list and look for a bind
 276                  * address that matches the source address of the returned dst.
 277                  */
 278                 sctp_v6_to_addr(&dst_saddr, &fl6->saddr, htons(bp->port));
 279                 rcu_read_lock();
 280                 list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 281                         if (!laddr->valid || laddr->state == SCTP_ADDR_DEL ||
 282                             (laddr->state != SCTP_ADDR_SRC &&
 283                              !asoc->src_out_of_asoc_ok))
 284                                 continue;
 285
 286                         /* Do not compare against v4 addrs */
 287                         if ((laddr->a.sa.sa_family == AF_INET6) &&
 288                             (sctp_v6_cmp_addr(&dst_saddr, &laddr->a))) {
 289                                 rcu_read_unlock();
 290                                 goto out;
 291                         }
 292                 }
 293                 rcu_read_unlock();
 294                 /* None of the bound addresses match the source address of the
 295                  * dst. So release it.
 296                  */
 297                 dst_release(dst);
 298                 dst = NULL;
 299         }
 300
 301         /* Walk through the bind address list and try to get the
 302          * best source address for a given destination.
 303          */
 304         rcu_read_lock();
 305         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 306                 if (!laddr->valid)
 307                         continue;
 308                 if ((laddr->state == SCTP_ADDR_SRC) &&
 309                     (laddr->a.sa.sa_family == AF_INET6) &&
 310                     (scope <= sctp_scope(&laddr->a))) {
 311                         bmatchlen = sctp_v6_addr_match_len(daddr, &laddr->a);
 312                         if (!baddr || (matchlen < bmatchlen)) {
 313                                 baddr = &laddr->a;
 314                                 matchlen = bmatchlen;
 315                         }
 316                 }
 317         }
 318         rcu_read_unlock();
 319
 320         if (baddr) {
 321                 fl6->saddr = baddr->v6.sin6_addr;
 322                 fl6->fl6_sport = baddr->v6.sin6_port;
 323                 final_p = fl6_update_dst(fl6, np->opt, &final);
 324                 dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
 325         }
 326
 327 out:
 328         if (!IS_ERR_OR_NULL(dst)) {
 329                 struct rt6_info *rt;
 330
 331                 rt = (struct rt6_info *)dst;
 332                 t->dst = dst;
 333                 t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 334                 pr_debug("rt6_dst:%pI6 rt6_src:%pI6\n", &rt->rt6i_dst.addr,
 335                          &fl6->saddr);
 336         } else {
 337                 t->dst = NULL;
 338
 339                 pr_debug("no route\n");
 340         }
 341 }
 342
 343 /* Returns the number of consecutive initial bits that match in the 2 ipv6
 344  * addresses.
 345  */
 346 static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
 347                                          union sctp_addr *s2)
 348 {
 349         return ipv6_addr_diff(&s1->v6.sin6_addr, &s2->v6.sin6_addr);
 350 }
 351
 352 /* Fills in the source address(saddr) based on the destination address(daddr)
 353  * and asoc's bind address list.
 354  */
 355 static void sctp_v6_get_saddr(struct sctp_sock *sk,
 356                               struct sctp_transport *t,
 357                               struct flowi *fl)
 358 {
 359         struct flowi6 *fl6 = &fl->u.ip6;
 360         union sctp_addr *saddr = &t->saddr;
 361
 362         pr_debug("%s: asoc:%p dst:%p\n", __func__, t->asoc, t->dst);
 363
 364         if (t->dst) {
 365                 saddr->v6.sin6_family = AF_INET6;
 366                 saddr->v6.sin6_addr = fl6->saddr;
 367         }
 368 }
 369
 370 /* Make a copy of all potential local addresses. */
 371 static void sctp_v6_copy_addrlist(struct list_head *addrlist,
 372                                   struct net_device *dev)
 373 {
 374         struct inet6_dev *in6_dev;
 375         struct inet6_ifaddr *ifp;
 376         struct sctp_sockaddr_entry *addr;
 377
 378         rcu_read_lock();
 379         if ((in6_dev = __in6_dev_get(dev)) == NULL) {
 380                 rcu_read_unlock();
 381                 return;
 382         }
 383
 384         read_lock_bh(&in6_dev->lock);
 385         list_for_each_entry(ifp, &in6_dev->addr_list, if_list) {
 386                 /* Add the address to the local list.  */
 387                 addr = kzalloc(sizeof(*addr), GFP_ATOMIC);
 388                 if (addr) {
 389                         addr->a.v6.sin6_family = AF_INET6;
 390                         addr->a.v6.sin6_port = 0;
 391                         addr->a.v6.sin6_addr = ifp->addr;
 392                         addr->a.v6.sin6_scope_id = dev->ifindex;
 393                         addr->valid = 1;
 394                         INIT_LIST_HEAD(&addr->list);
 395                         list_add_tail(&addr->list, addrlist);
 396                 }
 397         }
 398
 399         read_unlock_bh(&in6_dev->lock);
 400         rcu_read_unlock();
 401 }
 402
 403 /* Initialize a sockaddr_storage from in incoming skb. */
 404 static void sctp_v6_from_skb(union sctp_addr *addr,struct sk_buff *skb,
 405                              int is_saddr)
 406 {
 407         __be16 *port;
 408         struct sctphdr *sh;
 409
 410         port = &addr->v6.sin6_port;
 411         addr->v6.sin6_family = AF_INET6;
 412         addr->v6.sin6_flowinfo = 0; /* FIXME */
 413         addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;
 414
 415         sh = sctp_hdr(skb);
 416         if (is_saddr) {
 417                 *port  = sh->source;
 418                 addr->v6.sin6_addr = ipv6_hdr(skb)->saddr;
 419         } else {
 420                 *port = sh->dest;
 421                 addr->v6.sin6_addr = ipv6_hdr(skb)->daddr;
 422         }
 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 = sk->sk_v6_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                 sk->sk_v6_rcv_saddr.s6_addr32[0] = 0;
 438                 sk->sk_v6_rcv_saddr.s6_addr32[1] = 0;
 439                 sk->sk_v6_rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
 440                 sk->sk_v6_rcv_saddr.s6_addr32[3] =
 441                         addr->v4.sin_addr.s_addr;
 442         } else {
 443                 sk->sk_v6_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                 sk->sk_v6_daddr.s6_addr32[0] = 0;
 452                 sk->sk_v6_daddr.s6_addr32[1] = 0;
 453                 sk->sk_v6_daddr.s6_addr32[2] = htonl(0x0000ffff);
 454                 sk->sk_v6_daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
 455         } else {
 456                 sk->sk_v6_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         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         param->v6.addr = addr->v6.sin6_addr;
 483
 484         return length;
 485 }
 486
 487 /* Initialize a sctp_addr from struct in6_addr. */
 488 static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
 489                               __be16 port)
 490 {
 491         addr->sa.sa_family = AF_INET6;
 492         addr->v6.sin6_port = port;
 493         addr->v6.sin6_addr = *saddr;
 494 }
 495
 496 /* Compare addresses exactly.
 497  * v4-mapped-v6 is also in consideration.
 498  */
 499 static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
 500                             const union sctp_addr *addr2)
 501 {
 502         if (addr1->sa.sa_family != addr2->sa.sa_family) {
 503                 if (addr1->sa.sa_family == AF_INET &&
 504                     addr2->sa.sa_family == AF_INET6 &&
 505                     ipv6_addr_v4mapped(&addr2->v6.sin6_addr)) {
 506                         if (addr2->v6.sin6_port == addr1->v4.sin_port &&
 507                             addr2->v6.sin6_addr.s6_addr32[3] ==
 508                             addr1->v4.sin_addr.s_addr)
 509                                 return 1;
 510                 }
 511                 if (addr2->sa.sa_family == AF_INET &&
 512                     addr1->sa.sa_family == AF_INET6 &&
 513                     ipv6_addr_v4mapped(&addr1->v6.sin6_addr)) {
 514                         if (addr1->v6.sin6_port == addr2->v4.sin_port &&
 515                             addr1->v6.sin6_addr.s6_addr32[3] ==
 516                             addr2->v4.sin_addr.s_addr)
 517                                 return 1;
 518                 }
 519                 return 0;
 520         }
 521         if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
 522                 return 0;
 523         /* If this is a linklocal address, compare the scope_id. */
 524         if (ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
 525                 if (addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
 526                     (addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)) {
 527                         return 0;
 528                 }
 529         }
 530
 531         return 1;
 532 }
 533
 534 /* Initialize addr struct to INADDR_ANY. */
 535 static void sctp_v6_inaddr_any(union sctp_addr *addr, __be16 port)
 536 {
 537         memset(addr, 0x00, sizeof(union sctp_addr));
 538         addr->v6.sin6_family = AF_INET6;
 539         addr->v6.sin6_port = port;
 540 }
 541
 542 /* Is this a wildcard address? */
 543 static int sctp_v6_is_any(const union sctp_addr *addr)
 544 {
 545         return ipv6_addr_any(&addr->v6.sin6_addr);
 546 }
 547
 548 /* Should this be available for binding?   */
 549 static int sctp_v6_available(union sctp_addr *addr, struct sctp_sock *sp)
 550 {
 551         int type;
 552         const struct in6_addr *in6 = (const struct in6_addr *)&addr->v6.sin6_addr;
 553
 554         type = ipv6_addr_type(in6);
 555         if (IPV6_ADDR_ANY == type)
 556                 return 1;
 557         if (type == IPV6_ADDR_MAPPED) {
 558                 if (sp && !sp->v4mapped)
 559                         return 0;
 560                 if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
 561                         return 0;
 562                 sctp_v6_map_v4(addr);
 563                 return sctp_get_af_specific(AF_INET)->available(addr, sp);
 564         }
 565         if (!(type & IPV6_ADDR_UNICAST))
 566                 return 0;
 567
 568         return ipv6_chk_addr(sock_net(&sp->inet.sk), in6, NULL, 0);
 569 }
 570
 571 /* This function checks if the address is a valid address to be used for
 572  * SCTP.
 573  *
 574  * Output:
 575  * Return 0 - If the address is a non-unicast or an illegal address.
 576  * Return 1 - If the address is a unicast.
 577  */
 578 static int sctp_v6_addr_valid(union sctp_addr *addr,
 579                               struct sctp_sock *sp,
 580                               const struct sk_buff *skb)
 581 {
 582         int ret = ipv6_addr_type(&addr->v6.sin6_addr);
 583
 584         /* Support v4-mapped-v6 address. */
 585         if (ret == IPV6_ADDR_MAPPED) {
 586                 /* Note: This routine is used in input, so v4-mapped-v6
 587                  * are disallowed here when there is no sctp_sock.
 588                  */
 589                 if (!sp || !sp->v4mapped)
 590                         return 0;
 591                 if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
 592                         return 0;
 593                 sctp_v6_map_v4(addr);
 594                 return sctp_get_af_specific(AF_INET)->addr_valid(addr, sp, skb);
 595         }
 596
 597         /* Is this a non-unicast address */
 598         if (!(ret & IPV6_ADDR_UNICAST))
 599                 return 0;
 600
 601         return 1;
 602 }
 603
 604 /* What is the scope of 'addr'?  */
 605 static sctp_scope_t sctp_v6_scope(union sctp_addr *addr)
 606 {
 607         int v6scope;
 608         sctp_scope_t retval;
 609
 610         /* The IPv6 scope is really a set of bit fields.
 611          * See IFA_* in <net/if_inet6.h>.  Map to a generic SCTP scope.
 612          */
 613
 614         v6scope = ipv6_addr_scope(&addr->v6.sin6_addr);
 615         switch (v6scope) {
 616         case IFA_HOST:
 617                 retval = SCTP_SCOPE_LOOPBACK;
 618                 break;
 619         case IFA_LINK:
 620                 retval = SCTP_SCOPE_LINK;
 621                 break;
 622         case IFA_SITE:
 623                 retval = SCTP_SCOPE_PRIVATE;
 624                 break;
 625         default:
 626                 retval = SCTP_SCOPE_GLOBAL;
 627                 break;
 628         }
 629
 630         return retval;
 631 }
 632
 633 /* Create and initialize a new sk for the socket to be returned by accept(). */
 634 static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
 635                                              struct sctp_association *asoc)
 636 {
 637         struct sock *newsk;
 638         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
 639         struct sctp6_sock *newsctp6sk;
 640
 641         newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot);
 642         if (!newsk)
 643                 goto out;
 644
 645         sock_init_data(NULL, newsk);
 646
 647         sctp_copy_sock(newsk, sk, asoc);
 648         sock_reset_flag(sk, SOCK_ZAPPED);
 649
 650         newsctp6sk = (struct sctp6_sock *)newsk;
 651         inet_sk(newsk)->pinet6 = &newsctp6sk->inet6;
 652
 653         sctp_sk(newsk)->v4mapped = sctp_sk(sk)->v4mapped;
 654
 655         newnp = inet6_sk(newsk);
 656
 657         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
 658
 659         /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
 660          * and getpeername().
 661          */
 662         sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);
 663
 664         sk_refcnt_debug_inc(newsk);
 665
 666         if (newsk->sk_prot->init(newsk)) {
 667                 sk_common_release(newsk);
 668                 newsk = NULL;
 669         }
 670
 671 out:
 672         return newsk;
 673 }
 674
 675 /* Map v4 address to mapped v6 address */
 676 static void sctp_v6_addr_v4map(struct sctp_sock *sp, union sctp_addr *addr)
 677 {
 678         if (sp->v4mapped && AF_INET == addr->sa.sa_family)
 679                 sctp_v4_map_v6(addr);
 680 }
 681
 682 /* Where did this skb come from?  */
 683 static int sctp_v6_skb_iif(const struct sk_buff *skb)
 684 {
 685         struct inet6_skb_parm *opt = (struct inet6_skb_parm *) skb->cb;
 686         return opt->iif;
 687 }
 688
 689 /* Was this packet marked by Explicit Congestion Notification? */
 690 static int sctp_v6_is_ce(const struct sk_buff *skb)
 691 {
 692         return *((__u32 *)(ipv6_hdr(skb))) & htonl(1 << 20);
 693 }
 694
 695 /* Dump the v6 addr to the seq file. */
 696 static void sctp_v6_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
 697 {
 698         seq_printf(seq, "%pI6 ", &addr->v6.sin6_addr);
 699 }
 700
 701 static void sctp_v6_ecn_capable(struct sock *sk)
 702 {
 703         inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
 704 }
 705
 706 /* Initialize a PF_INET6 socket msg_name. */
 707 static void sctp_inet6_msgname(char *msgname, int *addr_len)
 708 {
 709         struct sockaddr_in6 *sin6;
 710
 711         sin6 = (struct sockaddr_in6 *)msgname;
 712         sin6->sin6_family = AF_INET6;
 713         sin6->sin6_flowinfo = 0;
 714         sin6->sin6_scope_id = 0; /*FIXME */
 715         *addr_len = sizeof(struct sockaddr_in6);
 716 }
 717
 718 /* Initialize a PF_INET msgname from a ulpevent. */
 719 static void sctp_inet6_event_msgname(struct sctp_ulpevent *event,
 720                                      char *msgname, int *addrlen)
 721 {
 722         struct sockaddr_in6 *sin6, *sin6from;
 723
 724         if (msgname) {
 725                 union sctp_addr *addr;
 726                 struct sctp_association *asoc;
 727
 728                 asoc = event->asoc;
 729                 sctp_inet6_msgname(msgname, addrlen);
 730                 sin6 = (struct sockaddr_in6 *)msgname;
 731                 sin6->sin6_port = htons(asoc->peer.port);
 732                 addr = &asoc->peer.primary_addr;
 733
 734                 /* Note: If we go to a common v6 format, this code
 735                  * will change.
 736                  */
 737
 738                 /* Map ipv4 address into v4-mapped-on-v6 address.  */
 739                 if (sctp_sk(asoc->base.sk)->v4mapped &&
 740                     AF_INET == addr->sa.sa_family) {
 741                         sctp_v4_map_v6((union sctp_addr *)sin6);
 742                         sin6->sin6_addr.s6_addr32[3] =
 743                                 addr->v4.sin_addr.s_addr;
 744                         return;
 745                 }
 746
 747                 sin6from = &asoc->peer.primary_addr.v6;
 748                 sin6->sin6_addr = sin6from->sin6_addr;
 749                 if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
 750                         sin6->sin6_scope_id = sin6from->sin6_scope_id;
 751         }
 752 }
 753
 754 /* Initialize a msg_name from an inbound skb. */
 755 static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
 756                                    int *addr_len)
 757 {
 758         struct sctphdr *sh;
 759         struct sockaddr_in6 *sin6;
 760
 761         if (msgname) {
 762                 sctp_inet6_msgname(msgname, addr_len);
 763                 sin6 = (struct sockaddr_in6 *)msgname;
 764                 sh = sctp_hdr(skb);
 765                 sin6->sin6_port = sh->source;
 766
 767                 /* Map ipv4 address into v4-mapped-on-v6 address. */
 768                 if (sctp_sk(skb->sk)->v4mapped &&
 769                     ip_hdr(skb)->version == 4) {
 770                         sctp_v4_map_v6((union sctp_addr *)sin6);
 771                         sin6->sin6_addr.s6_addr32[3] = ip_hdr(skb)->saddr;
 772                         return;
 773                 }
 774
 775                 /* Otherwise, just copy the v6 address. */
 776                 sin6->sin6_addr = ipv6_hdr(skb)->saddr;
 777                 if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL) {
 778                         struct sctp_ulpevent *ev = sctp_skb2event(skb);
 779                         sin6->sin6_scope_id = ev->iif;
 780                 }
 781         }
 782 }
 783
 784 /* Do we support this AF? */
 785 static int sctp_inet6_af_supported(sa_family_t family, struct sctp_sock *sp)
 786 {
 787         switch (family) {
 788         case AF_INET6:
 789                 return 1;
 790         /* v4-mapped-v6 addresses */
 791         case AF_INET:
 792                 if (!__ipv6_only_sock(sctp_opt2sk(sp)))
 793                         return 1;
 794         default:
 795                 return 0;
 796         }
 797 }
 798
 799 /* Address matching with wildcards allowed.  This extra level
 800  * of indirection lets us choose whether a PF_INET6 should
 801  * disallow any v4 addresses if we so choose.
 802  */
 803 static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
 804                                const union sctp_addr *addr2,
 805                                struct sctp_sock *opt)
 806 {
 807         struct sctp_af *af1, *af2;
 808         struct sock *sk = sctp_opt2sk(opt);
 809
 810         af1 = sctp_get_af_specific(addr1->sa.sa_family);
 811         af2 = sctp_get_af_specific(addr2->sa.sa_family);
 812
 813         if (!af1 || !af2)
 814                 return 0;
 815
 816         /* If the socket is IPv6 only, v4 addrs will not match */
 817         if (__ipv6_only_sock(sk) && af1 != af2)
 818                 return 0;
 819
 820         /* Today, wildcard AF_INET/AF_INET6. */
 821         if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
 822                 return 1;
 823
 824         if (addr1->sa.sa_family != addr2->sa.sa_family)
 825                 return 0;
 826
 827         return af1->cmp_addr(addr1, addr2);
 828 }
 829
 830 /* Verify that the provided sockaddr looks bindable.   Common verification,
 831  * has already been taken care of.
 832  */
 833 static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
 834 {
 835         struct sctp_af *af;
 836
 837         /* ASSERT: address family has already been verified. */
 838         if (addr->sa.sa_family != AF_INET6)
 839                 af = sctp_get_af_specific(addr->sa.sa_family);
 840         else {
 841                 int type = ipv6_addr_type(&addr->v6.sin6_addr);
 842                 struct net_device *dev;
 843
 844                 if (type & IPV6_ADDR_LINKLOCAL) {
 845                         struct net *net;
 846                         if (!addr->v6.sin6_scope_id)
 847                                 return 0;
 848                         net = sock_net(&opt->inet.sk);
 849                         rcu_read_lock();
 850                         dev = dev_get_by_index_rcu(net, addr->v6.sin6_scope_id);
 851                         if (!dev ||
 852                             !ipv6_chk_addr(net, &addr->v6.sin6_addr, dev, 0)) {
 853                                 rcu_read_unlock();
 854                                 return 0;
 855                         }
 856                         rcu_read_unlock();
 857                 } else if (type == IPV6_ADDR_MAPPED) {
 858                         if (!opt->v4mapped)
 859                                 return 0;
 860                 }
 861
 862                 af = opt->pf->af;
 863         }
 864         return af->available(addr, opt);
 865 }
 866
 867 /* Verify that the provided sockaddr looks sendable.   Common verification,
 868  * has already been taken care of.
 869  */
 870 static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
 871 {
 872         struct sctp_af *af = NULL;
 873
 874         /* ASSERT: address family has already been verified. */
 875         if (addr->sa.sa_family != AF_INET6)
 876                 af = sctp_get_af_specific(addr->sa.sa_family);
 877         else {
 878                 int type = ipv6_addr_type(&addr->v6.sin6_addr);
 879                 struct net_device *dev;
 880
 881                 if (type & IPV6_ADDR_LINKLOCAL) {
 882                         if (!addr->v6.sin6_scope_id)
 883                                 return 0;
 884                         rcu_read_lock();
 885                         dev = dev_get_by_index_rcu(sock_net(&opt->inet.sk),
 886                                                    addr->v6.sin6_scope_id);
 887                         rcu_read_unlock();
 888                         if (!dev)
 889                                 return 0;
 890                 }
 891                 af = opt->pf->af;
 892         }
 893
 894         return af != NULL;
 895 }
 896
 897 /* Fill in Supported Address Type information for INIT and INIT-ACK
 898  * chunks.   Note: In the future, we may want to look at sock options
 899  * to determine whether a PF_INET6 socket really wants to have IPV4
 900  * addresses.
 901  * Returns number of addresses supported.
 902  */
 903 static int sctp_inet6_supported_addrs(const struct sctp_sock *opt,
 904                                       __be16 *types)
 905 {
 906         types[0] = SCTP_PARAM_IPV6_ADDRESS;
 907         if (!opt || !ipv6_only_sock(sctp_opt2sk(opt))) {
 908                 types[1] = SCTP_PARAM_IPV4_ADDRESS;
 909                 return 2;
 910         }
 911         return 1;
 912 }
 913
 914 static const struct proto_ops inet6_seqpacket_ops = {
 915         .family            = PF_INET6,
 916         .owner             = THIS_MODULE,
 917         .release           = inet6_release,
 918         .bind              = inet6_bind,
 919         .connect           = inet_dgram_connect,
 920         .socketpair        = sock_no_socketpair,
 921         .accept            = inet_accept,
 922         .getname           = inet6_getname,
 923         .poll              = sctp_poll,
 924         .ioctl             = inet6_ioctl,
 925         .listen            = sctp_inet_listen,
 926         .shutdown          = inet_shutdown,
 927         .setsockopt        = sock_common_setsockopt,
 928         .getsockopt        = sock_common_getsockopt,
 929         .sendmsg           = inet_sendmsg,
 930         .recvmsg           = sock_common_recvmsg,
 931         .mmap              = sock_no_mmap,
 932 #ifdef CONFIG_COMPAT
 933         .compat_setsockopt = compat_sock_common_setsockopt,
 934         .compat_getsockopt = compat_sock_common_getsockopt,
 935 #endif
 936 };
 937
 938 static struct inet_protosw sctpv6_seqpacket_protosw = {
 939         .type          = SOCK_SEQPACKET,
 940         .protocol      = IPPROTO_SCTP,
 941         .prot          = &sctpv6_prot,
 942         .ops           = &inet6_seqpacket_ops,
 943         .no_check      = 0,
 944         .flags         = SCTP_PROTOSW_FLAG
 945 };
 946 static struct inet_protosw sctpv6_stream_protosw = {
 947         .type          = SOCK_STREAM,
 948         .protocol      = IPPROTO_SCTP,
 949         .prot          = &sctpv6_prot,
 950         .ops           = &inet6_seqpacket_ops,
 951         .no_check      = 0,
 952         .flags         = SCTP_PROTOSW_FLAG,
 953 };
 954
 955 static int sctp6_rcv(struct sk_buff *skb)
 956 {
 957         return sctp_rcv(skb) ? -1 : 0;
 958 }
 959
 960 static const struct inet6_protocol sctpv6_protocol = {
 961         .handler      = sctp6_rcv,
 962         .err_handler  = sctp_v6_err,
 963         .flags        = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
 964 };
 965
 966 static struct sctp_af sctp_af_inet6 = {
 967         .sa_family         = AF_INET6,
 968         .sctp_xmit         = sctp_v6_xmit,
 969         .setsockopt        = ipv6_setsockopt,
 970         .getsockopt        = ipv6_getsockopt,
 971         .get_dst           = sctp_v6_get_dst,
 972         .get_saddr         = sctp_v6_get_saddr,
 973         .copy_addrlist     = sctp_v6_copy_addrlist,
 974         .from_skb          = sctp_v6_from_skb,
 975         .from_sk           = sctp_v6_from_sk,
 976         .to_sk_saddr       = sctp_v6_to_sk_saddr,
 977         .to_sk_daddr       = sctp_v6_to_sk_daddr,
 978         .from_addr_param   = sctp_v6_from_addr_param,
 979         .to_addr_param     = sctp_v6_to_addr_param,
 980         .cmp_addr          = sctp_v6_cmp_addr,
 981         .scope             = sctp_v6_scope,
 982         .addr_valid        = sctp_v6_addr_valid,
 983         .inaddr_any        = sctp_v6_inaddr_any,
 984         .is_any            = sctp_v6_is_any,
 985         .available         = sctp_v6_available,
 986         .skb_iif           = sctp_v6_skb_iif,
 987         .is_ce             = sctp_v6_is_ce,
 988         .seq_dump_addr     = sctp_v6_seq_dump_addr,
 989         .ecn_capable       = sctp_v6_ecn_capable,
 990         .net_header_len    = sizeof(struct ipv6hdr),
 991         .sockaddr_len      = sizeof(struct sockaddr_in6),
 992 #ifdef CONFIG_COMPAT
 993         .compat_setsockopt = compat_ipv6_setsockopt,
 994         .compat_getsockopt = compat_ipv6_getsockopt,
 995 #endif
 996 };
 997
 998 static struct sctp_pf sctp_pf_inet6 = {
 999         .event_msgname = sctp_inet6_event_msgname,
1000         .skb_msgname   = sctp_inet6_skb_msgname,
1001         .af_supported  = sctp_inet6_af_supported,
1002         .cmp_addr      = sctp_inet6_cmp_addr,
1003         .bind_verify   = sctp_inet6_bind_verify,
1004         .send_verify   = sctp_inet6_send_verify,
1005         .supported_addrs = sctp_inet6_supported_addrs,
1006         .create_accept_sk = sctp_v6_create_accept_sk,
1007         .addr_v4map    = sctp_v6_addr_v4map,
1008         .af            = &sctp_af_inet6,
1009 };
1010
1011 /* Initialize IPv6 support and register with socket layer.  */
1012 void sctp_v6_pf_init(void)
1013 {
1014         /* Register the SCTP specific PF_INET6 functions. */
1015         sctp_register_pf(&sctp_pf_inet6, PF_INET6);
1016
1017         /* Register the SCTP specific AF_INET6 functions. */
1018         sctp_register_af(&sctp_af_inet6);
1019 }
1020
1021 void sctp_v6_pf_exit(void)
1022 {
1023         list_del(&sctp_af_inet6.list);
1024 }
1025
1026 /* Initialize IPv6 support and register with socket layer.  */
1027 int sctp_v6_protosw_init(void)
1028 {
1029         int rc;
1030
1031         rc = proto_register(&sctpv6_prot, 1);
1032         if (rc)
1033                 return rc;
1034
1035         /* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
1036         inet6_register_protosw(&sctpv6_seqpacket_protosw);
1037         inet6_register_protosw(&sctpv6_stream_protosw);
1038
1039         return 0;
1040 }
1041
1042 void sctp_v6_protosw_exit(void)
1043 {
1044         inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
1045         inet6_unregister_protosw(&sctpv6_stream_protosw);
1046         proto_unregister(&sctpv6_prot);
1047 }
1048
1049
1050 /* Register with inet6 layer. */
1051 int sctp_v6_add_protocol(void)
1052 {
1053         /* Register notifier for inet6 address additions/deletions. */
1054         register_inet6addr_notifier(&sctp_inet6addr_notifier);
1055
1056         if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
1057                 return -EAGAIN;
1058
1059         return 0;
1060 }
1061
1062 /* Unregister with inet6 layer. */
1063 void sctp_v6_del_protocol(void)
1064 {
1065         inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
1066         unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
1067 }