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=%pI6, type=%d, ifindex=%d) => %08x\n",
 190                   __func__, addr, type, ifindex, label);
 191
 192         return label;
 193 }
 194
 195 /* allocate one entry */
 196 static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
 197                                                  const struct in6_addr *prefix,
 198                                                  int prefixlen, int ifindex,
 199                                                  u32 label)
 200 {
 201         struct ip6addrlbl_entry *newp;
 202         int addrtype;
 203
 204         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n",
 205                   __func__, prefix, prefixlen, ifindex, (unsigned int)label);
 206
 207         addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
 208
 209         switch (addrtype) {
 210         case IPV6_ADDR_MAPPED:
 211                 if (prefixlen > 96)
 212                         return ERR_PTR(-EINVAL);
 213                 if (prefixlen < 96)
 214                         addrtype = 0;
 215                 break;
 216         case IPV6_ADDR_COMPATv4:
 217                 if (prefixlen != 96)
 218                         addrtype = 0;
 219                 break;
 220         case IPV6_ADDR_LOOPBACK:
 221                 if (prefixlen != 128)
 222                         addrtype = 0;
 223                 break;
 224         }
 225
 226         newp = kmalloc(sizeof(*newp), GFP_KERNEL);
 227         if (!newp)
 228                 return ERR_PTR(-ENOMEM);
 229
 230         ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
 231         newp->prefixlen = prefixlen;
 232         newp->ifindex = ifindex;
 233         newp->addrtype = addrtype;
 234         newp->label = label;
 235         INIT_HLIST_NODE(&newp->list);
 236 #ifdef CONFIG_NET_NS
 237         newp->lbl_net = hold_net(net);
 238 #endif
 239         atomic_set(&newp->refcnt, 1);
 240         return newp;
 241 }
 242
 243 /* add a label */
 244 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 245 {
 246         int ret = 0;
 247
 248         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
 249                         __func__,
 250                         newp, replace);
 251
 252         if (hlist_empty(&ip6addrlbl_table.head)) {
 253                 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
 254         } else {
 255                 struct hlist_node *pos, *n;
 256                 struct ip6addrlbl_entry *p = NULL;
 257                 hlist_for_each_entry_safe(p, pos, n,
 258                                           &ip6addrlbl_table.head, list) {
 259                         if (p->prefixlen == newp->prefixlen &&
 260                             net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
 261                             p->ifindex == newp->ifindex &&
 262                             ipv6_addr_equal(&p->prefix, &newp->prefix)) {
 263                                 if (!replace) {
 264                                         ret = -EEXIST;
 265                                         goto out;
 266                                 }
 267                                 hlist_replace_rcu(&p->list, &newp->list);
 268                                 ip6addrlbl_put(p);
 269                                 goto out;
 270                         } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
 271                                    (p->prefixlen < newp->prefixlen)) {
 272                                 hlist_add_before_rcu(&newp->list, &p->list);
 273                                 goto out;
 274                         }
 275                 }
 276                 hlist_add_after_rcu(&p->list, &newp->list);
 277         }
 278 out:
 279         if (!ret)
 280                 ip6addrlbl_table.seq++;
 281         return ret;
 282 }
 283
 284 /* add a label */
 285 static int ip6addrlbl_add(struct net *net,
 286                           const struct in6_addr *prefix, int prefixlen,
 287                           int ifindex, u32 label, int replace)
 288 {
 289         struct ip6addrlbl_entry *newp;
 290         int ret = 0;
 291
 292         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
 293                   __func__, prefix, prefixlen, ifindex, (unsigned int)label,
 294                   replace);
 295
 296         newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
 297         if (IS_ERR(newp))
 298                 return PTR_ERR(newp);
 299         spin_lock(&ip6addrlbl_table.lock);
 300         ret = __ip6addrlbl_add(newp, replace);
 301         spin_unlock(&ip6addrlbl_table.lock);
 302         if (ret)
 303                 ip6addrlbl_free(newp);
 304         return ret;
 305 }
 306
 307 /* remove a label */
 308 static int __ip6addrlbl_del(struct net *net,
 309                             const struct in6_addr *prefix, int prefixlen,
 310                             int ifindex)
 311 {
 312         struct ip6addrlbl_entry *p = NULL;
 313         struct hlist_node *pos, *n;
 314         int ret = -ESRCH;
 315
 316         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
 317                   __func__, prefix, prefixlen, ifindex);
 318
 319         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 320                 if (p->prefixlen == prefixlen &&
 321                     net_eq(ip6addrlbl_net(p), net) &&
 322                     p->ifindex == ifindex &&
 323                     ipv6_addr_equal(&p->prefix, prefix)) {
 324                         hlist_del_rcu(&p->list);
 325                         ip6addrlbl_put(p);
 326                         ret = 0;
 327                         break;
 328                 }
 329         }
 330         return ret;
 331 }
 332
 333 static int ip6addrlbl_del(struct net *net,
 334                           const struct in6_addr *prefix, int prefixlen,
 335                           int ifindex)
 336 {
 337         struct in6_addr prefix_buf;
 338         int ret;
 339
 340         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
 341                   __func__, prefix, prefixlen, ifindex);
 342
 343         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
 344         spin_lock(&ip6addrlbl_table.lock);
 345         ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
 346         spin_unlock(&ip6addrlbl_table.lock);
 347         return ret;
 348 }
 349
 350 /* add default label */
 351 static int __net_init ip6addrlbl_net_init(struct net *net)
 352 {
 353         int err = 0;
 354         int i;
 355
 356         ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
 357
 358         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 359                 int ret = ip6addrlbl_add(net,
 360                                          ip6addrlbl_init_table[i].prefix,
 361                                          ip6addrlbl_init_table[i].prefixlen,
 362                                          0,
 363                                          ip6addrlbl_init_table[i].label, 0);
 364                 /* XXX: should we free all rules when we catch an error? */
 365                 if (ret && (!err || err != -ENOMEM))
 366                         err = ret;
 367         }
 368         return err;
 369 }
 370
 371 static void __net_exit ip6addrlbl_net_exit(struct net *net)
 372 {
 373         struct ip6addrlbl_entry *p = NULL;
 374         struct hlist_node *pos, *n;
 375
 376         /* Remove all labels belonging to the exiting net */
 377         spin_lock(&ip6addrlbl_table.lock);
 378         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 379                 if (net_eq(ip6addrlbl_net(p), net)) {
 380                         hlist_del_rcu(&p->list);
 381                         ip6addrlbl_put(p);
 382                 }
 383         }
 384         spin_unlock(&ip6addrlbl_table.lock);
 385 }
 386
 387 static struct pernet_operations ipv6_addr_label_ops = {
 388         .init = ip6addrlbl_net_init,
 389         .exit = ip6addrlbl_net_exit,
 390 };
 391
 392 int __init ipv6_addr_label_init(void)
 393 {
 394         spin_lock_init(&ip6addrlbl_table.lock);
 395
 396         return register_pernet_subsys(&ipv6_addr_label_ops);
 397 }
 398
 399 static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 400         [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
 401         [IFAL_LABEL]            = { .len = sizeof(u32), },
 402 };
 403
 404 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 405                              void *arg)
 406 {
 407         struct net *net = sock_net(skb->sk);
 408         struct ifaddrlblmsg *ifal;
 409         struct nlattr *tb[IFAL_MAX+1];
 410         struct in6_addr *pfx;
 411         u32 label;
 412         int err = 0;
 413
 414         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 415         if (err < 0)
 416                 return err;
 417
 418         ifal = nlmsg_data(nlh);
 419
 420         if (ifal->ifal_family != AF_INET6 ||
 421             ifal->ifal_prefixlen > 128)
 422                 return -EINVAL;
 423
 424         if (ifal->ifal_index &&
 425             !__dev_get_by_index(net, ifal->ifal_index))
 426                 return -EINVAL;
 427
 428         if (!tb[IFAL_ADDRESS])
 429                 return -EINVAL;
 430
 431         pfx = nla_data(tb[IFAL_ADDRESS]);
 432         if (!pfx)
 433                 return -EINVAL;
 434
 435         if (!tb[IFAL_LABEL])
 436                 return -EINVAL;
 437         label = nla_get_u32(tb[IFAL_LABEL]);
 438         if (label == IPV6_ADDR_LABEL_DEFAULT)
 439                 return -EINVAL;
 440
 441         switch(nlh->nlmsg_type) {
 442         case RTM_NEWADDRLABEL:
 443                 err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
 444                                      ifal->ifal_index, label,
 445                                      nlh->nlmsg_flags & NLM_F_REPLACE);
 446                 break;
 447         case RTM_DELADDRLABEL:
 448                 err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
 449                                      ifal->ifal_index);
 450                 break;
 451         default:
 452                 err = -EOPNOTSUPP;
 453         }
 454         return err;
 455 }
 456
 457 static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
 458                                      int prefixlen, int ifindex, u32 lseq)
 459 {
 460         struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
 461         ifal->ifal_family = AF_INET6;
 462         ifal->ifal_prefixlen = prefixlen;
 463         ifal->ifal_flags = 0;
 464         ifal->ifal_index = ifindex;
 465         ifal->ifal_seq = lseq;
 466 };
 467
 468 static int ip6addrlbl_fill(struct sk_buff *skb,
 469                            struct ip6addrlbl_entry *p,
 470                            u32 lseq,
 471                            u32 pid, u32 seq, int event,
 472                            unsigned int flags)
 473 {
 474         struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
 475                                          sizeof(struct ifaddrlblmsg), flags);
 476         if (!nlh)
 477                 return -EMSGSIZE;
 478
 479         ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
 480
 481         if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
 482             nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
 483                 nlmsg_cancel(skb, nlh);
 484                 return -EMSGSIZE;
 485         }
 486
 487         return nlmsg_end(skb, nlh);
 488 }
 489
 490 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 491 {
 492         struct net *net = sock_net(skb->sk);
 493         struct ip6addrlbl_entry *p;
 494         struct hlist_node *pos;
 495         int idx = 0, s_idx = cb->args[0];
 496         int err;
 497
 498         rcu_read_lock();
 499         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 500                 if (idx >= s_idx &&
 501                     net_eq(ip6addrlbl_net(p), net)) {
 502                         if ((err = ip6addrlbl_fill(skb, p,
 503                                                    ip6addrlbl_table.seq,
 504                                                    NETLINK_CB(cb->skb).pid,
 505                                                    cb->nlh->nlmsg_seq,
 506                                                    RTM_NEWADDRLABEL,
 507                                                    NLM_F_MULTI)) <= 0)
 508                                 break;
 509                 }
 510                 idx++;
 511         }
 512         rcu_read_unlock();
 513         cb->args[0] = idx;
 514         return skb->len;
 515 }
 516
 517 static inline int ip6addrlbl_msgsize(void)
 518 {
 519         return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
 520                 + nla_total_size(16)    /* IFAL_ADDRESS */
 521                 + nla_total_size(4)     /* IFAL_LABEL */
 522         );
 523 }
 524
 525 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 526                           void *arg)
 527 {
 528         struct net *net = sock_net(in_skb->sk);
 529         struct ifaddrlblmsg *ifal;
 530         struct nlattr *tb[IFAL_MAX+1];
 531         struct in6_addr *addr;
 532         u32 lseq;
 533         int err = 0;
 534         struct ip6addrlbl_entry *p;
 535         struct sk_buff *skb;
 536
 537         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 538         if (err < 0)
 539                 return err;
 540
 541         ifal = nlmsg_data(nlh);
 542
 543         if (ifal->ifal_family != AF_INET6 ||
 544             ifal->ifal_prefixlen != 128)
 545                 return -EINVAL;
 546
 547         if (ifal->ifal_index &&
 548             !__dev_get_by_index(net, ifal->ifal_index))
 549                 return -EINVAL;
 550
 551         if (!tb[IFAL_ADDRESS])
 552                 return -EINVAL;
 553
 554         addr = nla_data(tb[IFAL_ADDRESS]);
 555         if (!addr)
 556                 return -EINVAL;
 557
 558         rcu_read_lock();
 559         p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
 560         if (p && ip6addrlbl_hold(p))
 561                 p = NULL;
 562         lseq = ip6addrlbl_table.seq;
 563         rcu_read_unlock();
 564
 565         if (!p) {
 566                 err = -ESRCH;
 567                 goto out;
 568         }
 569
 570         if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
 571                 ip6addrlbl_put(p);
 572                 return -ENOBUFS;
 573         }
 574
 575         err = ip6addrlbl_fill(skb, p, lseq,
 576                               NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 577                               RTM_NEWADDRLABEL, 0);
 578
 579         ip6addrlbl_put(p);
 580
 581         if (err < 0) {
 582                 WARN_ON(err == -EMSGSIZE);
 583                 kfree_skb(skb);
 584                 goto out;
 585         }
 586
 587         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
 588 out:
 589         return err;
 590 }
 591
 592 void __init ipv6_addr_label_rtnl_register(void)
 593 {
 594         __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
 595         __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
 596         __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
 597 }
 598