net/ipv6/addrlabel.c

   1 /*
   2  * IPv6 Address Label subsystem
   3  * for the IPv6 "Default" Source Address Selection
   4  *
   5  * Copyright (C)2007 USAGI/WIDE Project
   6  */
   7 /*
   8  * Author:
   9  *      YOSHIFUJI Hideaki @ USAGI/WIDE Project <yoshfuji@linux-ipv6.org>
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/list.h>
  14 #include <linux/rcupdate.h>
  15 #include <linux/in6.h>
  16 #include <net/addrconf.h>
  17 #include <linux/if_addrlabel.h>
  18 #include <linux/netlink.h>
  19 #include <linux/rtnetlink.h>
  20
  21 #if 0
  22 #define ADDRLABEL(x...) printk(x)
  23 #else
  24 #define ADDRLABEL(x...) do { ; } while(0)
  25 #endif
  26
  27 /*
  28  * Policy Table
  29  */
  30 struct ip6addrlbl_entry
  31 {
  32 #ifdef CONFIG_NET_NS
  33         struct net *lbl_net;
  34 #endif
  35         struct in6_addr prefix;
  36         int prefixlen;
  37         int ifindex;
  38         int addrtype;
  39         u32 label;
  40         struct hlist_node list;
  41         atomic_t refcnt;
  42         struct rcu_head rcu;
  43 };
  44
  45 static struct ip6addrlbl_table
  46 {
  47         struct hlist_head head;
  48         spinlock_t lock;
  49         u32 seq;
  50 } ip6addrlbl_table;
  51
  52 static inline
  53 struct net *ip6addrlbl_net(const struct ip6addrlbl_entry *lbl)
  54 {
  55 #ifdef CONFIG_NET_NS
  56         return lbl->lbl_net;
  57 #else
  58         return &init_net;
  59 #endif
  60 }
  61
  62 /*
  63  * Default policy table (RFC3484 + extensions)
  64  *
  65  * prefix               addr_type       label
  66  * -------------------------------------------------------------------------
  67  * ::1/128              LOOPBACK        0
  68  * ::/0                 N/A             1
  69  * 2002::/16            N/A             2
  70  * ::/96                COMPATv4        3
  71  * ::ffff:0:0/96        V4MAPPED        4
  72  * fc00::/7             N/A             5               ULA (RFC 4193)
  73  * 2001::/32            N/A             6               Teredo (RFC 4380)
  74  * 2001:10::/28         N/A             7               ORCHID (RFC 4843)
  75  *
  76  * Note: 0xffffffff is used if we do not have any policies.
  77  */
  78
  79 #define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
  80
  81 static const __net_initdata struct ip6addrlbl_init_table
  82 {
  83         const struct in6_addr *prefix;
  84         int prefixlen;
  85         u32 label;
  86 } ip6addrlbl_init_table[] = {
  87         {       /* ::/0 */
  88                 .prefix = &in6addr_any,
  89                 .label = 1,
  90         },{     /* fc00::/7 */
  91                 .prefix = &(struct in6_addr){{{ 0xfc }}},
  92                 .prefixlen = 7,
  93                 .label = 5,
  94         },{     /* 2002::/16 */
  95                 .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
  96                 .prefixlen = 16,
  97                 .label = 2,
  98         },{     /* 2001::/32 */
  99                 .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
 100                 .prefixlen = 32,
 101                 .label = 6,
 102         },{     /* 2001:10::/28 */
 103                 .prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}},
 104                 .prefixlen = 28,
 105                 .label = 7,
 106         },{     /* ::ffff:0:0 */
 107                 .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
 108                 .prefixlen = 96,
 109                 .label = 4,
 110         },{     /* ::/96 */
 111                 .prefix = &in6addr_any,
 112                 .prefixlen = 96,
 113                 .label = 3,
 114         },{     /* ::1/128 */
 115                 .prefix = &in6addr_loopback,
 116                 .prefixlen = 128,
 117                 .label = 0,
 118         }
 119 };
 120
 121 /* Object management */
 122 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 123 {
 124 #ifdef CONFIG_NET_NS
 125         release_net(p->lbl_net);
 126 #endif
 127         kfree(p);
 128 }
 129
 130 static void ip6addrlbl_free_rcu(struct rcu_head *h)
 131 {
 132         ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
 133 }
 134
 135 static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
 136 {
 137         return atomic_inc_not_zero(&p->refcnt);
 138 }
 139
 140 static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
 141 {
 142         if (atomic_dec_and_test(&p->refcnt))
 143                 call_rcu(&p->rcu, ip6addrlbl_free_rcu);
 144 }
 145
 146 /* Find label */
 147 static int __ip6addrlbl_match(struct net *net,
 148                               struct ip6addrlbl_entry *p,
 149                               const struct in6_addr *addr,
 150                               int addrtype, int ifindex)
 151 {
 152         if (!net_eq(ip6addrlbl_net(p), net))
 153                 return 0;
 154         if (p->ifindex && p->ifindex != ifindex)
 155                 return 0;
 156         if (p->addrtype && p->addrtype != addrtype)
 157                 return 0;
 158         if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
 159                 return 0;
 160         return 1;
 161 }
 162
 163 static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
 164                                                   const struct in6_addr *addr,
 165                                                   int type, int ifindex)
 166 {
 167         struct hlist_node *pos;
 168         struct ip6addrlbl_entry *p;
 169         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 170                 if (__ip6addrlbl_match(net, p, addr, type, ifindex))
 171                         return p;
 172         }
 173         return NULL;
 174 }
 175
 176 u32 ipv6_addr_label(struct net *net,
 177                     const struct in6_addr *addr, int type, int ifindex)
 178 {
 179         u32 label;
 180         struct ip6addrlbl_entry *p;
 181
 182         type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
 183
 184         rcu_read_lock();
 185         p = __ipv6_addr_label(net, addr, type, ifindex);
 186         label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
 187         rcu_read_unlock();
 188
 189         ADDRLABEL(KERN_DEBUG "%s(addr=" NIP6_FMT ", type=%d, ifindex=%d) => %08x\n",
 190                         __func__,
 191                         NIP6(*addr), type, ifindex,
 192                         label);
 193
 194         return label;
 195 }
 196
 197 /* allocate one entry */
 198 static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
 199                                                  const struct in6_addr *prefix,
 200                                                  int prefixlen, int ifindex,
 201                                                  u32 label)
 202 {
 203         struct ip6addrlbl_entry *newp;
 204         int addrtype;
 205
 206         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u)\n",
 207                         __func__,
 208                         NIP6(*prefix), prefixlen,
 209                         ifindex,
 210                         (unsigned int)label);
 211
 212         addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
 213
 214         switch (addrtype) {
 215         case IPV6_ADDR_MAPPED:
 216                 if (prefixlen > 96)
 217                         return ERR_PTR(-EINVAL);
 218                 if (prefixlen < 96)
 219                         addrtype = 0;
 220                 break;
 221         case IPV6_ADDR_COMPATv4:
 222                 if (prefixlen != 96)
 223                         addrtype = 0;
 224                 break;
 225         case IPV6_ADDR_LOOPBACK:
 226                 if (prefixlen != 128)
 227                         addrtype = 0;
 228                 break;
 229         }
 230
 231         newp = kmalloc(sizeof(*newp), GFP_KERNEL);
 232         if (!newp)
 233                 return ERR_PTR(-ENOMEM);
 234
 235         ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
 236         newp->prefixlen = prefixlen;
 237         newp->ifindex = ifindex;
 238         newp->addrtype = addrtype;
 239         newp->label = label;
 240         INIT_HLIST_NODE(&newp->list);
 241 #ifdef CONFIG_NET_NS
 242         newp->lbl_net = hold_net(net);
 243 #endif
 244         atomic_set(&newp->refcnt, 1);
 245         return newp;
 246 }
 247
 248 /* add a label */
 249 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 250 {
 251         int ret = 0;
 252
 253         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
 254                         __func__,
 255                         newp, replace);
 256
 257         if (hlist_empty(&ip6addrlbl_table.head)) {
 258                 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
 259         } else {
 260                 struct hlist_node *pos, *n;
 261                 struct ip6addrlbl_entry *p = NULL;
 262                 hlist_for_each_entry_safe(p, pos, n,
 263                                           &ip6addrlbl_table.head, list) {
 264                         if (p->prefixlen == newp->prefixlen &&
 265                             net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
 266                             p->ifindex == newp->ifindex &&
 267                             ipv6_addr_equal(&p->prefix, &newp->prefix)) {
 268                                 if (!replace) {
 269                                         ret = -EEXIST;
 270                                         goto out;
 271                                 }
 272                                 hlist_replace_rcu(&p->list, &newp->list);
 273                                 ip6addrlbl_put(p);
 274                                 goto out;
 275                         } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
 276                                    (p->prefixlen < newp->prefixlen)) {
 277                                 hlist_add_before_rcu(&newp->list, &p->list);
 278                                 goto out;
 279                         }
 280                 }
 281                 hlist_add_after_rcu(&p->list, &newp->list);
 282         }
 283 out:
 284         if (!ret)
 285                 ip6addrlbl_table.seq++;
 286         return ret;
 287 }
 288
 289 /* add a label */
 290 static int ip6addrlbl_add(struct net *net,
 291                           const struct in6_addr *prefix, int prefixlen,
 292                           int ifindex, u32 label, int replace)
 293 {
 294         struct ip6addrlbl_entry *newp;
 295         int ret = 0;
 296
 297         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
 298                         __func__,
 299                         NIP6(*prefix), prefixlen,
 300                         ifindex,
 301                         (unsigned int)label,
 302                         replace);
 303
 304         newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
 305         if (IS_ERR(newp))
 306                 return PTR_ERR(newp);
 307         spin_lock(&ip6addrlbl_table.lock);
 308         ret = __ip6addrlbl_add(newp, replace);
 309         spin_unlock(&ip6addrlbl_table.lock);
 310         if (ret)
 311                 ip6addrlbl_free(newp);
 312         return ret;
 313 }
 314
 315 /* remove a label */
 316 static int __ip6addrlbl_del(struct net *net,
 317                             const struct in6_addr *prefix, int prefixlen,
 318                             int ifindex)
 319 {
 320         struct ip6addrlbl_entry *p = NULL;
 321         struct hlist_node *pos, *n;
 322         int ret = -ESRCH;
 323
 324         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 325                         __func__,
 326                         NIP6(*prefix), prefixlen,
 327                         ifindex);
 328
 329         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 330                 if (p->prefixlen == prefixlen &&
 331                     net_eq(ip6addrlbl_net(p), net) &&
 332                     p->ifindex == ifindex &&
 333                     ipv6_addr_equal(&p->prefix, prefix)) {
 334                         hlist_del_rcu(&p->list);
 335                         ip6addrlbl_put(p);
 336                         ret = 0;
 337                         break;
 338                 }
 339         }
 340         return ret;
 341 }
 342
 343 static int ip6addrlbl_del(struct net *net,
 344                           const struct in6_addr *prefix, int prefixlen,
 345                           int ifindex)
 346 {
 347         struct in6_addr prefix_buf;
 348         int ret;
 349
 350         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 351                         __func__,
 352                         NIP6(*prefix), prefixlen,
 353                         ifindex);
 354
 355         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
 356         spin_lock(&ip6addrlbl_table.lock);
 357         ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
 358         spin_unlock(&ip6addrlbl_table.lock);
 359         return ret;
 360 }
 361
 362 /* add default label */
 363 static int __net_init ip6addrlbl_net_init(struct net *net)
 364 {
 365         int err = 0;
 366         int i;
 367
 368         ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
 369
 370         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 371                 int ret = ip6addrlbl_add(net,
 372                                          ip6addrlbl_init_table[i].prefix,
 373                                          ip6addrlbl_init_table[i].prefixlen,
 374                                          0,
 375                                          ip6addrlbl_init_table[i].label, 0);
 376                 /* XXX: should we free all rules when we catch an error? */
 377                 if (ret && (!err || err != -ENOMEM))
 378                         err = ret;
 379         }
 380         return err;
 381 }
 382
 383 static void __net_exit ip6addrlbl_net_exit(struct net *net)
 384 {
 385         struct ip6addrlbl_entry *p = NULL;
 386         struct hlist_node *pos, *n;
 387
 388         /* Remove all labels belonging to the exiting net */
 389         spin_lock(&ip6addrlbl_table.lock);
 390         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 391                 if (net_eq(ip6addrlbl_net(p), net)) {
 392                         hlist_del_rcu(&p->list);
 393                         ip6addrlbl_put(p);
 394                 }
 395         }
 396         spin_unlock(&ip6addrlbl_table.lock);
 397 }
 398
 399 static struct pernet_operations ipv6_addr_label_ops = {
 400         .init = ip6addrlbl_net_init,
 401         .exit = ip6addrlbl_net_exit,
 402 };
 403
 404 int __init ipv6_addr_label_init(void)
 405 {
 406         spin_lock_init(&ip6addrlbl_table.lock);
 407
 408         return register_pernet_subsys(&ipv6_addr_label_ops);
 409 }
 410
 411 static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 412         [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
 413         [IFAL_LABEL]            = { .len = sizeof(u32), },
 414 };
 415
 416 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 417                              void *arg)
 418 {
 419         struct net *net = sock_net(skb->sk);
 420         struct ifaddrlblmsg *ifal;
 421         struct nlattr *tb[IFAL_MAX+1];
 422         struct in6_addr *pfx;
 423         u32 label;
 424         int err = 0;
 425
 426         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 427         if (err < 0)
 428                 return err;
 429
 430         ifal = nlmsg_data(nlh);
 431
 432         if (ifal->ifal_family != AF_INET6 ||
 433             ifal->ifal_prefixlen > 128)
 434                 return -EINVAL;
 435
 436         if (ifal->ifal_index &&
 437             !__dev_get_by_index(net, ifal->ifal_index))
 438                 return -EINVAL;
 439
 440         if (!tb[IFAL_ADDRESS])
 441                 return -EINVAL;
 442
 443         pfx = nla_data(tb[IFAL_ADDRESS]);
 444         if (!pfx)
 445                 return -EINVAL;
 446
 447         if (!tb[IFAL_LABEL])
 448                 return -EINVAL;
 449         label = nla_get_u32(tb[IFAL_LABEL]);
 450         if (label == IPV6_ADDR_LABEL_DEFAULT)
 451                 return -EINVAL;
 452
 453         switch(nlh->nlmsg_type) {
 454         case RTM_NEWADDRLABEL:
 455                 err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
 456                                      ifal->ifal_index, label,
 457                                      nlh->nlmsg_flags & NLM_F_REPLACE);
 458                 break;
 459         case RTM_DELADDRLABEL:
 460                 err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
 461                                      ifal->ifal_index);
 462                 break;
 463         default:
 464                 err = -EOPNOTSUPP;
 465         }
 466         return err;
 467 }
 468
 469 static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
 470                                      int prefixlen, int ifindex, u32 lseq)
 471 {
 472         struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
 473         ifal->ifal_family = AF_INET6;
 474         ifal->ifal_prefixlen = prefixlen;
 475         ifal->ifal_flags = 0;
 476         ifal->ifal_index = ifindex;
 477         ifal->ifal_seq = lseq;
 478 };
 479
 480 static int ip6addrlbl_fill(struct sk_buff *skb,
 481                            struct ip6addrlbl_entry *p,
 482                            u32 lseq,
 483                            u32 pid, u32 seq, int event,
 484                            unsigned int flags)
 485 {
 486         struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
 487                                          sizeof(struct ifaddrlblmsg), flags);
 488         if (!nlh)
 489                 return -EMSGSIZE;
 490
 491         ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
 492
 493         if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
 494             nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
 495                 nlmsg_cancel(skb, nlh);
 496                 return -EMSGSIZE;
 497         }
 498
 499         return nlmsg_end(skb, nlh);
 500 }
 501
 502 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 503 {
 504         struct net *net = sock_net(skb->sk);
 505         struct ip6addrlbl_entry *p;
 506         struct hlist_node *pos;
 507         int idx = 0, s_idx = cb->args[0];
 508         int err;
 509
 510         rcu_read_lock();
 511         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 512                 if (idx >= s_idx &&
 513                     net_eq(ip6addrlbl_net(p), net)) {
 514                         if ((err = ip6addrlbl_fill(skb, p,
 515                                                    ip6addrlbl_table.seq,
 516                                                    NETLINK_CB(cb->skb).pid,
 517                                                    cb->nlh->nlmsg_seq,
 518                                                    RTM_NEWADDRLABEL,
 519                                                    NLM_F_MULTI)) <= 0)
 520                                 break;
 521                 }
 522                 idx++;
 523         }
 524         rcu_read_unlock();
 525         cb->args[0] = idx;
 526         return skb->len;
 527 }
 528
 529 static inline int ip6addrlbl_msgsize(void)
 530 {
 531         return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
 532                 + nla_total_size(16)    /* IFAL_ADDRESS */
 533                 + nla_total_size(4)     /* IFAL_LABEL */
 534         );
 535 }
 536
 537 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 538                           void *arg)
 539 {
 540         struct net *net = sock_net(in_skb->sk);
 541         struct ifaddrlblmsg *ifal;
 542         struct nlattr *tb[IFAL_MAX+1];
 543         struct in6_addr *addr;
 544         u32 lseq;
 545         int err = 0;
 546         struct ip6addrlbl_entry *p;
 547         struct sk_buff *skb;
 548
 549         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 550         if (err < 0)
 551                 return err;
 552
 553         ifal = nlmsg_data(nlh);
 554
 555         if (ifal->ifal_family != AF_INET6 ||
 556             ifal->ifal_prefixlen != 128)
 557                 return -EINVAL;
 558
 559         if (ifal->ifal_index &&
 560             !__dev_get_by_index(net, ifal->ifal_index))
 561                 return -EINVAL;
 562
 563         if (!tb[IFAL_ADDRESS])
 564                 return -EINVAL;
 565
 566         addr = nla_data(tb[IFAL_ADDRESS]);
 567         if (!addr)
 568                 return -EINVAL;
 569
 570         rcu_read_lock();
 571         p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
 572         if (p && ip6addrlbl_hold(p))
 573                 p = NULL;
 574         lseq = ip6addrlbl_table.seq;
 575         rcu_read_unlock();
 576
 577         if (!p) {
 578                 err = -ESRCH;
 579                 goto out;
 580         }
 581
 582         if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
 583                 ip6addrlbl_put(p);
 584                 return -ENOBUFS;
 585         }
 586
 587         err = ip6addrlbl_fill(skb, p, lseq,
 588                               NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 589                               RTM_NEWADDRLABEL, 0);
 590
 591         ip6addrlbl_put(p);
 592
 593         if (err < 0) {
 594                 WARN_ON(err == -EMSGSIZE);
 595                 kfree_skb(skb);
 596                 goto out;
 597         }
 598
 599         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
 600 out:
 601         return err;
 602 }
 603
 604 void __init ipv6_addr_label_rtnl_register(void)
 605 {
 606         __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
 607         __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
 608         __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
 609 }
 610