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 <linux/slab.h>
  17 #include <net/addrconf.h>
  18 #include <linux/if_addrlabel.h>
  19 #include <linux/netlink.h>
  20 #include <linux/rtnetlink.h>
  21
  22 #if 0
  23 #define ADDRLABEL(x...) printk(x)
  24 #else
  25 #define ADDRLABEL(x...) do { ; } while(0)
  26 #endif
  27
  28 /*
  29  * Policy Table
  30  */
  31 struct ip6addrlbl_entry
  32 {
  33 #ifdef CONFIG_NET_NS
  34         struct net *lbl_net;
  35 #endif
  36         struct in6_addr prefix;
  37         int prefixlen;
  38         int ifindex;
  39         int addrtype;
  40         u32 label;
  41         struct hlist_node list;
  42         atomic_t refcnt;
  43         struct rcu_head rcu;
  44 };
  45
  46 static struct ip6addrlbl_table
  47 {
  48         struct hlist_head head;
  49         spinlock_t lock;
  50         u32 seq;
  51 } ip6addrlbl_table;
  52
  53 static inline
  54 struct net *ip6addrlbl_net(const struct ip6addrlbl_entry *lbl)
  55 {
  56 #ifdef CONFIG_NET_NS
  57         return lbl->lbl_net;
  58 #else
  59         return &init_net;
  60 #endif
  61 }
  62
  63 /*
  64  * Default policy table (RFC3484 + extensions)
  65  *
  66  * prefix               addr_type       label
  67  * -------------------------------------------------------------------------
  68  * ::1/128              LOOPBACK        0
  69  * ::/0                 N/A             1
  70  * 2002::/16            N/A             2
  71  * ::/96                COMPATv4        3
  72  * ::ffff:0:0/96        V4MAPPED        4
  73  * fc00::/7             N/A             5               ULA (RFC 4193)
  74  * 2001::/32            N/A             6               Teredo (RFC 4380)
  75  * 2001:10::/28         N/A             7               ORCHID (RFC 4843)
  76  *
  77  * Note: 0xffffffff is used if we do not have any policies.
  78  */
  79
  80 #define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
  81
  82 static const __net_initdata struct ip6addrlbl_init_table
  83 {
  84         const struct in6_addr *prefix;
  85         int prefixlen;
  86         u32 label;
  87 } ip6addrlbl_init_table[] = {
  88         {       /* ::/0 */
  89                 .prefix = &in6addr_any,
  90                 .label = 1,
  91         },{     /* fc00::/7 */
  92                 .prefix = &(struct in6_addr){{{ 0xfc }}},
  93                 .prefixlen = 7,
  94                 .label = 5,
  95         },{     /* 2002::/16 */
  96                 .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
  97                 .prefixlen = 16,
  98                 .label = 2,
  99         },{     /* 2001::/32 */
 100                 .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
 101                 .prefixlen = 32,
 102                 .label = 6,
 103         },{     /* 2001:10::/28 */
 104                 .prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}},
 105                 .prefixlen = 28,
 106                 .label = 7,
 107         },{     /* ::ffff:0:0 */
 108                 .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
 109                 .prefixlen = 96,
 110                 .label = 4,
 111         },{     /* ::/96 */
 112                 .prefix = &in6addr_any,
 113                 .prefixlen = 96,
 114                 .label = 3,
 115         },{     /* ::1/128 */
 116                 .prefix = &in6addr_loopback,
 117                 .prefixlen = 128,
 118                 .label = 0,
 119         }
 120 };
 121
 122 /* Object management */
 123 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 124 {
 125 #ifdef CONFIG_NET_NS
 126         release_net(p->lbl_net);
 127 #endif
 128         kfree(p);
 129 }
 130
 131 static void ip6addrlbl_free_rcu(struct rcu_head *h)
 132 {
 133         ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
 134 }
 135
 136 static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
 137 {
 138         return atomic_inc_not_zero(&p->refcnt);
 139 }
 140
 141 static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
 142 {
 143         if (atomic_dec_and_test(&p->refcnt))
 144                 call_rcu(&p->rcu, ip6addrlbl_free_rcu);
 145 }
 146
 147 /* Find label */
 148 static int __ip6addrlbl_match(struct net *net,
 149                               struct ip6addrlbl_entry *p,
 150                               const struct in6_addr *addr,
 151                               int addrtype, int ifindex)
 152 {
 153         if (!net_eq(ip6addrlbl_net(p), net))
 154                 return 0;
 155         if (p->ifindex && p->ifindex != ifindex)
 156                 return 0;
 157         if (p->addrtype && p->addrtype != addrtype)
 158                 return 0;
 159         if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
 160                 return 0;
 161         return 1;
 162 }
 163
 164 static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
 165                                                   const struct in6_addr *addr,
 166                                                   int type, int ifindex)
 167 {
 168         struct hlist_node *pos;
 169         struct ip6addrlbl_entry *p;
 170         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 171                 if (__ip6addrlbl_match(net, p, addr, type, ifindex))
 172                         return p;
 173         }
 174         return NULL;
 175 }
 176
 177 u32 ipv6_addr_label(struct net *net,
 178                     const struct in6_addr *addr, int type, int ifindex)
 179 {
 180         u32 label;
 181         struct ip6addrlbl_entry *p;
 182
 183         type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
 184
 185         rcu_read_lock();
 186         p = __ipv6_addr_label(net, addr, type, ifindex);
 187         label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
 188         rcu_read_unlock();
 189
 190         ADDRLABEL(KERN_DEBUG "%s(addr=%pI6, type=%d, ifindex=%d) => %08x\n",
 191                   __func__, addr, type, ifindex, label);
 192
 193         return label;
 194 }
 195
 196 /* allocate one entry */
 197 static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
 198                                                  const struct in6_addr *prefix,
 199                                                  int prefixlen, int ifindex,
 200                                                  u32 label)
 201 {
 202         struct ip6addrlbl_entry *newp;
 203         int addrtype;
 204
 205         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n",
 206                   __func__, prefix, prefixlen, ifindex, (unsigned int)label);
 207
 208         addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
 209
 210         switch (addrtype) {
 211         case IPV6_ADDR_MAPPED:
 212                 if (prefixlen > 96)
 213                         return ERR_PTR(-EINVAL);
 214                 if (prefixlen < 96)
 215                         addrtype = 0;
 216                 break;
 217         case IPV6_ADDR_COMPATv4:
 218                 if (prefixlen != 96)
 219                         addrtype = 0;
 220                 break;
 221         case IPV6_ADDR_LOOPBACK:
 222                 if (prefixlen != 128)
 223                         addrtype = 0;
 224                 break;
 225         }
 226
 227         newp = kmalloc(sizeof(*newp), GFP_KERNEL);
 228         if (!newp)
 229                 return ERR_PTR(-ENOMEM);
 230
 231         ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
 232         newp->prefixlen = prefixlen;
 233         newp->ifindex = ifindex;
 234         newp->addrtype = addrtype;
 235         newp->label = label;
 236         INIT_HLIST_NODE(&newp->list);
 237 #ifdef CONFIG_NET_NS
 238         newp->lbl_net = hold_net(net);
 239 #endif
 240         atomic_set(&newp->refcnt, 1);
 241         return newp;
 242 }
 243
 244 /* add a label */
 245 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 246 {
 247         int ret = 0;
 248
 249         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
 250                         __func__,
 251                         newp, replace);
 252
 253         if (hlist_empty(&ip6addrlbl_table.head)) {
 254                 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
 255         } else {
 256                 struct hlist_node *pos, *n;
 257                 struct ip6addrlbl_entry *p = NULL;
 258                 hlist_for_each_entry_safe(p, pos, n,
 259                                           &ip6addrlbl_table.head, list) {
 260                         if (p->prefixlen == newp->prefixlen &&
 261                             net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
 262                             p->ifindex == newp->ifindex &&
 263                             ipv6_addr_equal(&p->prefix, &newp->prefix)) {
 264                                 if (!replace) {
 265                                         ret = -EEXIST;
 266                                         goto out;
 267                                 }
 268                                 hlist_replace_rcu(&p->list, &newp->list);
 269                                 ip6addrlbl_put(p);
 270                                 goto out;
 271                         } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
 272                                    (p->prefixlen < newp->prefixlen)) {
 273                                 hlist_add_before_rcu(&newp->list, &p->list);
 274                                 goto out;
 275                         }
 276                 }
 277                 hlist_add_after_rcu(&p->list, &newp->list);
 278         }
 279 out:
 280         if (!ret)
 281                 ip6addrlbl_table.seq++;
 282         return ret;
 283 }
 284
 285 /* add a label */
 286 static int ip6addrlbl_add(struct net *net,
 287                           const struct in6_addr *prefix, int prefixlen,
 288                           int ifindex, u32 label, int replace)
 289 {
 290         struct ip6addrlbl_entry *newp;
 291         int ret = 0;
 292
 293         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
 294                   __func__, prefix, prefixlen, ifindex, (unsigned int)label,
 295                   replace);
 296
 297         newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
 298         if (IS_ERR(newp))
 299                 return PTR_ERR(newp);
 300         spin_lock(&ip6addrlbl_table.lock);
 301         ret = __ip6addrlbl_add(newp, replace);
 302         spin_unlock(&ip6addrlbl_table.lock);
 303         if (ret)
 304                 ip6addrlbl_free(newp);
 305         return ret;
 306 }
 307
 308 /* remove a label */
 309 static int __ip6addrlbl_del(struct net *net,
 310                             const struct in6_addr *prefix, int prefixlen,
 311                             int ifindex)
 312 {
 313         struct ip6addrlbl_entry *p = NULL;
 314         struct hlist_node *pos, *n;
 315         int ret = -ESRCH;
 316
 317         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
 318                   __func__, prefix, prefixlen, ifindex);
 319
 320         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 321                 if (p->prefixlen == prefixlen &&
 322                     net_eq(ip6addrlbl_net(p), net) &&
 323                     p->ifindex == ifindex &&
 324                     ipv6_addr_equal(&p->prefix, prefix)) {
 325                         hlist_del_rcu(&p->list);
 326                         ip6addrlbl_put(p);
 327                         ret = 0;
 328                         break;
 329                 }
 330         }
 331         return ret;
 332 }
 333
 334 static int ip6addrlbl_del(struct net *net,
 335                           const struct in6_addr *prefix, int prefixlen,
 336                           int ifindex)
 337 {
 338         struct in6_addr prefix_buf;
 339         int ret;
 340
 341         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
 342                   __func__, prefix, prefixlen, ifindex);
 343
 344         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
 345         spin_lock(&ip6addrlbl_table.lock);
 346         ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
 347         spin_unlock(&ip6addrlbl_table.lock);
 348         return ret;
 349 }
 350
 351 /* add default label */
 352 static int __net_init ip6addrlbl_net_init(struct net *net)
 353 {
 354         int err = 0;
 355         int i;
 356
 357         ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
 358
 359         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 360                 int ret = ip6addrlbl_add(net,
 361                                          ip6addrlbl_init_table[i].prefix,
 362                                          ip6addrlbl_init_table[i].prefixlen,
 363                                          0,
 364                                          ip6addrlbl_init_table[i].label, 0);
 365                 /* XXX: should we free all rules when we catch an error? */
 366                 if (ret && (!err || err != -ENOMEM))
 367                         err = ret;
 368         }
 369         return err;
 370 }
 371
 372 static void __net_exit ip6addrlbl_net_exit(struct net *net)
 373 {
 374         struct ip6addrlbl_entry *p = NULL;
 375         struct hlist_node *pos, *n;
 376
 377         /* Remove all labels belonging to the exiting net */
 378         spin_lock(&ip6addrlbl_table.lock);
 379         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 380                 if (net_eq(ip6addrlbl_net(p), net)) {
 381                         hlist_del_rcu(&p->list);
 382                         ip6addrlbl_put(p);
 383                 }
 384         }
 385         spin_unlock(&ip6addrlbl_table.lock);
 386 }
 387
 388 static struct pernet_operations ipv6_addr_label_ops = {
 389         .init = ip6addrlbl_net_init,
 390         .exit = ip6addrlbl_net_exit,
 391 };
 392
 393 int __init ipv6_addr_label_init(void)
 394 {
 395         spin_lock_init(&ip6addrlbl_table.lock);
 396
 397         return register_pernet_subsys(&ipv6_addr_label_ops);
 398 }
 399
 400 static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 401         [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
 402         [IFAL_LABEL]            = { .len = sizeof(u32), },
 403 };
 404
 405 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 406                              void *arg)
 407 {
 408         struct net *net = sock_net(skb->sk);
 409         struct ifaddrlblmsg *ifal;
 410         struct nlattr *tb[IFAL_MAX+1];
 411         struct in6_addr *pfx;
 412         u32 label;
 413         int err = 0;
 414
 415         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 416         if (err < 0)
 417                 return err;
 418
 419         ifal = nlmsg_data(nlh);
 420
 421         if (ifal->ifal_family != AF_INET6 ||
 422             ifal->ifal_prefixlen > 128)
 423                 return -EINVAL;
 424
 425         if (ifal->ifal_index &&
 426             !__dev_get_by_index(net, ifal->ifal_index))
 427                 return -EINVAL;
 428
 429         if (!tb[IFAL_ADDRESS])
 430                 return -EINVAL;
 431
 432         pfx = nla_data(tb[IFAL_ADDRESS]);
 433         if (!pfx)
 434                 return -EINVAL;
 435
 436         if (!tb[IFAL_LABEL])
 437                 return -EINVAL;
 438         label = nla_get_u32(tb[IFAL_LABEL]);
 439         if (label == IPV6_ADDR_LABEL_DEFAULT)
 440                 return -EINVAL;
 441
 442         switch(nlh->nlmsg_type) {
 443         case RTM_NEWADDRLABEL:
 444                 err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
 445                                      ifal->ifal_index, label,
 446                                      nlh->nlmsg_flags & NLM_F_REPLACE);
 447                 break;
 448         case RTM_DELADDRLABEL:
 449                 err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
 450                                      ifal->ifal_index);
 451                 break;
 452         default:
 453                 err = -EOPNOTSUPP;
 454         }
 455         return err;
 456 }
 457
 458 static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
 459                                      int prefixlen, int ifindex, u32 lseq)
 460 {
 461         struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
 462         ifal->ifal_family = AF_INET6;
 463         ifal->ifal_prefixlen = prefixlen;
 464         ifal->ifal_flags = 0;
 465         ifal->ifal_index = ifindex;
 466         ifal->ifal_seq = lseq;
 467 };
 468
 469 static int ip6addrlbl_fill(struct sk_buff *skb,
 470                            struct ip6addrlbl_entry *p,
 471                            u32 lseq,
 472                            u32 pid, u32 seq, int event,
 473                            unsigned int flags)
 474 {
 475         struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
 476                                          sizeof(struct ifaddrlblmsg), flags);
 477         if (!nlh)
 478                 return -EMSGSIZE;
 479
 480         ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
 481
 482         if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
 483             nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
 484                 nlmsg_cancel(skb, nlh);
 485                 return -EMSGSIZE;
 486         }
 487
 488         return nlmsg_end(skb, nlh);
 489 }
 490
 491 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 492 {
 493         struct net *net = sock_net(skb->sk);
 494         struct ip6addrlbl_entry *p;
 495         struct hlist_node *pos;
 496         int idx = 0, s_idx = cb->args[0];
 497         int err;
 498
 499         rcu_read_lock();
 500         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 501                 if (idx >= s_idx &&
 502                     net_eq(ip6addrlbl_net(p), net)) {
 503                         if ((err = ip6addrlbl_fill(skb, p,
 504                                                    ip6addrlbl_table.seq,
 505                                                    NETLINK_CB(cb->skb).pid,
 506                                                    cb->nlh->nlmsg_seq,
 507                                                    RTM_NEWADDRLABEL,
 508                                                    NLM_F_MULTI)) <= 0)
 509                                 break;
 510                 }
 511                 idx++;
 512         }
 513         rcu_read_unlock();
 514         cb->args[0] = idx;
 515         return skb->len;
 516 }
 517
 518 static inline int ip6addrlbl_msgsize(void)
 519 {
 520         return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
 521                 + nla_total_size(16)    /* IFAL_ADDRESS */
 522                 + nla_total_size(4)     /* IFAL_LABEL */
 523         );
 524 }
 525
 526 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 527                           void *arg)
 528 {
 529         struct net *net = sock_net(in_skb->sk);
 530         struct ifaddrlblmsg *ifal;
 531         struct nlattr *tb[IFAL_MAX+1];
 532         struct in6_addr *addr;
 533         u32 lseq;
 534         int err = 0;
 535         struct ip6addrlbl_entry *p;
 536         struct sk_buff *skb;
 537
 538         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 539         if (err < 0)
 540                 return err;
 541
 542         ifal = nlmsg_data(nlh);
 543
 544         if (ifal->ifal_family != AF_INET6 ||
 545             ifal->ifal_prefixlen != 128)
 546                 return -EINVAL;
 547
 548         if (ifal->ifal_index &&
 549             !__dev_get_by_index(net, ifal->ifal_index))
 550                 return -EINVAL;
 551
 552         if (!tb[IFAL_ADDRESS])
 553                 return -EINVAL;
 554
 555         addr = nla_data(tb[IFAL_ADDRESS]);
 556         if (!addr)
 557                 return -EINVAL;
 558
 559         rcu_read_lock();
 560         p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
 561         if (p && ip6addrlbl_hold(p))
 562                 p = NULL;
 563         lseq = ip6addrlbl_table.seq;
 564         rcu_read_unlock();
 565
 566         if (!p) {
 567                 err = -ESRCH;
 568                 goto out;
 569         }
 570
 571         if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
 572                 ip6addrlbl_put(p);
 573                 return -ENOBUFS;
 574         }
 575
 576         err = ip6addrlbl_fill(skb, p, lseq,
 577                               NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 578                               RTM_NEWADDRLABEL, 0);
 579
 580         ip6addrlbl_put(p);
 581
 582         if (err < 0) {
 583                 WARN_ON(err == -EMSGSIZE);
 584                 kfree_skb(skb);
 585                 goto out;
 586         }
 587
 588         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
 589 out:
 590         return err;
 591 }
 592
 593 void __init ipv6_addr_label_rtnl_register(void)
 594 {
 595         __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
 596         __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
 597         __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
 598 }
 599