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         struct in6_addr prefix;
  33         int prefixlen;
  34         int ifindex;
  35         int addrtype;
  36         u32 label;
  37         struct hlist_node list;
  38         atomic_t refcnt;
  39         struct rcu_head rcu;
  40 };
  41
  42 static struct ip6addrlbl_table
  43 {
  44         struct hlist_head head;
  45         spinlock_t lock;
  46         u32 seq;
  47 } ip6addrlbl_table;
  48
  49 /*
  50  * Default policy table (RFC3484 + extensions)
  51  *
  52  * prefix               addr_type       label
  53  * -------------------------------------------------------------------------
  54  * ::1/128              LOOPBACK        0
  55  * ::/0                 N/A             1
  56  * 2002::/16            N/A             2
  57  * ::/96                COMPATv4        3
  58  * ::ffff:0:0/96        V4MAPPED        4
  59  * fc00::/7             N/A             5               ULA (RFC 4193)
  60  * 2001::/32            N/A             6               Teredo (RFC 4380)
  61  *
  62  * Note: 0xffffffff is used if we do not have any policies.
  63  */
  64
  65 #define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
  66
  67 static const __initdata struct ip6addrlbl_init_table
  68 {
  69         const struct in6_addr *prefix;
  70         int prefixlen;
  71         u32 label;
  72 } ip6addrlbl_init_table[] = {
  73         {       /* ::/0 */
  74                 .prefix = &in6addr_any,
  75                 .label = 1,
  76         },{     /* fc00::/7 */
  77                 .prefix = &(struct in6_addr){{{ 0xfc }}},
  78                 .prefixlen = 7,
  79                 .label = 5,
  80         },{     /* 2002::/16 */
  81                 .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
  82                 .prefixlen = 16,
  83                 .label = 2,
  84         },{     /* 2001::/32 */
  85                 .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
  86                 .prefixlen = 32,
  87                 .label = 6,
  88         },{     /* ::ffff:0:0 */
  89                 .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
  90                 .prefixlen = 96,
  91                 .label = 4,
  92         },{     /* ::/96 */
  93                 .prefix = &in6addr_any,
  94                 .prefixlen = 96,
  95                 .label = 3,
  96         },{     /* ::1/128 */
  97                 .prefix = &in6addr_loopback,
  98                 .prefixlen = 128,
  99                 .label = 0,
 100         }
 101 };
 102
 103 /* Object management */
 104 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 105 {
 106         kfree(p);
 107 }
 108
 109 static void ip6addrlbl_free_rcu(struct rcu_head *h)
 110 {
 111         ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
 112 }
 113
 114 static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
 115 {
 116         return atomic_inc_not_zero(&p->refcnt);
 117 }
 118
 119 static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
 120 {
 121         if (atomic_dec_and_test(&p->refcnt))
 122                 call_rcu(&p->rcu, ip6addrlbl_free_rcu);
 123 }
 124
 125 /* Find label */
 126 static int __ip6addrlbl_match(struct ip6addrlbl_entry *p,
 127                               const struct in6_addr *addr,
 128                               int addrtype, int ifindex)
 129 {
 130         if (p->ifindex && p->ifindex != ifindex)
 131                 return 0;
 132         if (p->addrtype && p->addrtype != addrtype)
 133                 return 0;
 134         if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
 135                 return 0;
 136         return 1;
 137 }
 138
 139 static struct ip6addrlbl_entry *__ipv6_addr_label(const struct in6_addr *addr,
 140                                                   int type, int ifindex)
 141 {
 142         struct hlist_node *pos;
 143         struct ip6addrlbl_entry *p;
 144         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 145                 if (__ip6addrlbl_match(p, addr, type, ifindex))
 146                         return p;
 147         }
 148         return NULL;
 149 }
 150
 151 u32 ipv6_addr_label(const struct in6_addr *addr, int type, int ifindex)
 152 {
 153         u32 label;
 154         struct ip6addrlbl_entry *p;
 155
 156         type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
 157
 158         rcu_read_lock();
 159         p = __ipv6_addr_label(addr, type, ifindex);
 160         label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
 161         rcu_read_unlock();
 162
 163         ADDRLABEL(KERN_DEBUG "%s(addr=" NIP6_FMT ", type=%d, ifindex=%d) => %08x\n",
 164                         __FUNCTION__,
 165                         NIP6(*addr), type, ifindex,
 166                         label);
 167
 168         return label;
 169 }
 170
 171 /* allocate one entry */
 172 static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
 173                                                  int prefixlen, int ifindex,
 174                                                  u32 label)
 175 {
 176         struct ip6addrlbl_entry *newp;
 177         int addrtype;
 178
 179         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u)\n",
 180                         __FUNCTION__,
 181                         NIP6(*prefix), prefixlen,
 182                         ifindex,
 183                         (unsigned int)label);
 184
 185         addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
 186
 187         switch (addrtype) {
 188         case IPV6_ADDR_MAPPED:
 189                 if (prefixlen > 96)
 190                         return ERR_PTR(-EINVAL);
 191                 if (prefixlen < 96)
 192                         addrtype = 0;
 193                 break;
 194         case IPV6_ADDR_COMPATv4:
 195                 if (prefixlen != 96)
 196                         addrtype = 0;
 197                 break;
 198         case IPV6_ADDR_LOOPBACK:
 199                 if (prefixlen != 128)
 200                         addrtype = 0;
 201                 break;
 202         }
 203
 204         newp = kmalloc(sizeof(*newp), GFP_KERNEL);
 205         if (!newp)
 206                 return ERR_PTR(-ENOMEM);
 207
 208         ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
 209         newp->prefixlen = prefixlen;
 210         newp->ifindex = ifindex;
 211         newp->addrtype = addrtype;
 212         newp->label = label;
 213         INIT_HLIST_NODE(&newp->list);
 214         atomic_set(&newp->refcnt, 1);
 215         return newp;
 216 }
 217
 218 /* add a label */
 219 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 220 {
 221         int ret = 0;
 222
 223         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
 224                         __FUNCTION__,
 225                         newp, replace);
 226
 227         if (hlist_empty(&ip6addrlbl_table.head)) {
 228                 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
 229         } else {
 230                 struct hlist_node *pos, *n;
 231                 struct ip6addrlbl_entry *p = NULL;
 232                 hlist_for_each_entry_safe(p, pos, n,
 233                                           &ip6addrlbl_table.head, list) {
 234                         if (p->prefixlen == newp->prefixlen &&
 235                             p->ifindex == newp->ifindex &&
 236                             ipv6_addr_equal(&p->prefix, &newp->prefix)) {
 237                                 if (!replace) {
 238                                         ret = -EEXIST;
 239                                         goto out;
 240                                 }
 241                                 hlist_replace_rcu(&p->list, &newp->list);
 242                                 ip6addrlbl_put(p);
 243                                 goto out;
 244                         } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
 245                                    (p->prefixlen < newp->prefixlen)) {
 246                                 hlist_add_before_rcu(&newp->list, &p->list);
 247                                 goto out;
 248                         }
 249                 }
 250                 hlist_add_after_rcu(&p->list, &newp->list);
 251         }
 252 out:
 253         if (!ret)
 254                 ip6addrlbl_table.seq++;
 255         return ret;
 256 }
 257
 258 /* add a label */
 259 static int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
 260                           int ifindex, u32 label, int replace)
 261 {
 262         struct ip6addrlbl_entry *newp;
 263         int ret = 0;
 264
 265         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
 266                         __FUNCTION__,
 267                         NIP6(*prefix), prefixlen,
 268                         ifindex,
 269                         (unsigned int)label,
 270                         replace);
 271
 272         newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
 273         if (IS_ERR(newp))
 274                 return PTR_ERR(newp);
 275         spin_lock(&ip6addrlbl_table.lock);
 276         ret = __ip6addrlbl_add(newp, replace);
 277         spin_unlock(&ip6addrlbl_table.lock);
 278         if (ret)
 279                 ip6addrlbl_free(newp);
 280         return ret;
 281 }
 282
 283 /* remove a label */
 284 static int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 285                             int ifindex)
 286 {
 287         struct ip6addrlbl_entry *p = NULL;
 288         struct hlist_node *pos, *n;
 289         int ret = -ESRCH;
 290
 291         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 292                         __FUNCTION__,
 293                         NIP6(*prefix), prefixlen,
 294                         ifindex);
 295
 296         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 297                 if (p->prefixlen == prefixlen &&
 298                     p->ifindex == ifindex &&
 299                     ipv6_addr_equal(&p->prefix, prefix)) {
 300                         hlist_del_rcu(&p->list);
 301                         ip6addrlbl_put(p);
 302                         ret = 0;
 303                         break;
 304                 }
 305         }
 306         return ret;
 307 }
 308
 309 static int ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 310                           int ifindex)
 311 {
 312         struct in6_addr prefix_buf;
 313         int ret;
 314
 315         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 316                         __FUNCTION__,
 317                         NIP6(*prefix), prefixlen,
 318                         ifindex);
 319
 320         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
 321         spin_lock(&ip6addrlbl_table.lock);
 322         ret = __ip6addrlbl_del(&prefix_buf, prefixlen, ifindex);
 323         spin_unlock(&ip6addrlbl_table.lock);
 324         return ret;
 325 }
 326
 327 /* add default label */
 328 static __init int ip6addrlbl_init(void)
 329 {
 330         int err = 0;
 331         int i;
 332
 333         ADDRLABEL(KERN_DEBUG "%s()\n", __FUNCTION__);
 334
 335         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 336                 int ret = ip6addrlbl_add(ip6addrlbl_init_table[i].prefix,
 337                                          ip6addrlbl_init_table[i].prefixlen,
 338                                          0,
 339                                          ip6addrlbl_init_table[i].label, 0);
 340                 /* XXX: should we free all rules when we catch an error? */
 341                 if (ret && (!err || err != -ENOMEM))
 342                         err = ret;
 343         }
 344         return err;
 345 }
 346
 347 int __init ipv6_addr_label_init(void)
 348 {
 349         spin_lock_init(&ip6addrlbl_table.lock);
 350
 351         return ip6addrlbl_init();
 352 }
 353
 354 static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 355         [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
 356         [IFAL_LABEL]            = { .len = sizeof(u32), },
 357 };
 358
 359 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 360                              void *arg)
 361 {
 362         struct net *net = skb->sk->sk_net;
 363         struct ifaddrlblmsg *ifal;
 364         struct nlattr *tb[IFAL_MAX+1];
 365         struct in6_addr *pfx;
 366         u32 label;
 367         int err = 0;
 368
 369         if (net != &init_net)
 370                 return 0;
 371
 372         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 373         if (err < 0)
 374                 return err;
 375
 376         ifal = nlmsg_data(nlh);
 377
 378         if (ifal->ifal_family != AF_INET6 ||
 379             ifal->ifal_prefixlen > 128)
 380                 return -EINVAL;
 381
 382         if (ifal->ifal_index &&
 383             !__dev_get_by_index(&init_net, ifal->ifal_index))
 384                 return -EINVAL;
 385
 386         if (!tb[IFAL_ADDRESS])
 387                 return -EINVAL;
 388
 389         pfx = nla_data(tb[IFAL_ADDRESS]);
 390         if (!pfx)
 391                 return -EINVAL;
 392
 393         if (!tb[IFAL_LABEL])
 394                 return -EINVAL;
 395         label = nla_get_u32(tb[IFAL_LABEL]);
 396         if (label == IPV6_ADDR_LABEL_DEFAULT)
 397                 return -EINVAL;
 398
 399         switch(nlh->nlmsg_type) {
 400         case RTM_NEWADDRLABEL:
 401                 err = ip6addrlbl_add(pfx, ifal->ifal_prefixlen,
 402                                      ifal->ifal_index, label,
 403                                      nlh->nlmsg_flags & NLM_F_REPLACE);
 404                 break;
 405         case RTM_DELADDRLABEL:
 406                 err = ip6addrlbl_del(pfx, ifal->ifal_prefixlen,
 407                                      ifal->ifal_index);
 408                 break;
 409         default:
 410                 err = -EOPNOTSUPP;
 411         }
 412         return err;
 413 }
 414
 415 static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
 416                                      int prefixlen, int ifindex, u32 lseq)
 417 {
 418         struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
 419         ifal->ifal_family = AF_INET6;
 420         ifal->ifal_prefixlen = prefixlen;
 421         ifal->ifal_flags = 0;
 422         ifal->ifal_index = ifindex;
 423         ifal->ifal_seq = lseq;
 424 };
 425
 426 static int ip6addrlbl_fill(struct sk_buff *skb,
 427                            struct ip6addrlbl_entry *p,
 428                            u32 lseq,
 429                            u32 pid, u32 seq, int event,
 430                            unsigned int flags)
 431 {
 432         struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
 433                                          sizeof(struct ifaddrlblmsg), flags);
 434         if (!nlh)
 435                 return -EMSGSIZE;
 436
 437         ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
 438
 439         if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
 440             nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
 441                 nlmsg_cancel(skb, nlh);
 442                 return -EMSGSIZE;
 443         }
 444
 445         return nlmsg_end(skb, nlh);
 446 }
 447
 448 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 449 {
 450         struct net *net = skb->sk->sk_net;
 451         struct ip6addrlbl_entry *p;
 452         struct hlist_node *pos;
 453         int idx = 0, s_idx = cb->args[0];
 454         int err;
 455
 456         if (net != &init_net)
 457                 return 0;
 458
 459         rcu_read_lock();
 460         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 461                 if (idx >= s_idx) {
 462                         if ((err = ip6addrlbl_fill(skb, p,
 463                                                    ip6addrlbl_table.seq,
 464                                                    NETLINK_CB(cb->skb).pid,
 465                                                    cb->nlh->nlmsg_seq,
 466                                                    RTM_NEWADDRLABEL,
 467                                                    NLM_F_MULTI)) <= 0)
 468                                 break;
 469                 }
 470                 idx++;
 471         }
 472         rcu_read_unlock();
 473         cb->args[0] = idx;
 474         return skb->len;
 475 }
 476
 477 static inline int ip6addrlbl_msgsize(void)
 478 {
 479         return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
 480                 + nla_total_size(16)    /* IFAL_ADDRESS */
 481                 + nla_total_size(4)     /* IFAL_LABEL */
 482         );
 483 }
 484
 485 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 486                           void *arg)
 487 {
 488         struct net *net = in_skb->sk->sk_net;
 489         struct ifaddrlblmsg *ifal;
 490         struct nlattr *tb[IFAL_MAX+1];
 491         struct in6_addr *addr;
 492         u32 lseq;
 493         int err = 0;
 494         struct ip6addrlbl_entry *p;
 495         struct sk_buff *skb;
 496
 497         if (net != &init_net)
 498                 return 0;
 499
 500         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 501         if (err < 0)
 502                 return err;
 503
 504         ifal = nlmsg_data(nlh);
 505
 506         if (ifal->ifal_family != AF_INET6 ||
 507             ifal->ifal_prefixlen != 128)
 508                 return -EINVAL;
 509
 510         if (ifal->ifal_index &&
 511             !__dev_get_by_index(&init_net, ifal->ifal_index))
 512                 return -EINVAL;
 513
 514         if (!tb[IFAL_ADDRESS])
 515                 return -EINVAL;
 516
 517         addr = nla_data(tb[IFAL_ADDRESS]);
 518         if (!addr)
 519                 return -EINVAL;
 520
 521         rcu_read_lock();
 522         p = __ipv6_addr_label(addr, ipv6_addr_type(addr), ifal->ifal_index);
 523         if (p && ip6addrlbl_hold(p))
 524                 p = NULL;
 525         lseq = ip6addrlbl_table.seq;
 526         rcu_read_unlock();
 527
 528         if (!p) {
 529                 err = -ESRCH;
 530                 goto out;
 531         }
 532
 533         if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
 534                 ip6addrlbl_put(p);
 535                 return -ENOBUFS;
 536         }
 537
 538         err = ip6addrlbl_fill(skb, p, lseq,
 539                               NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 540                               RTM_NEWADDRLABEL, 0);
 541
 542         ip6addrlbl_put(p);
 543
 544         if (err < 0) {
 545                 WARN_ON(err == -EMSGSIZE);
 546                 kfree_skb(skb);
 547                 goto out;
 548         }
 549
 550         err = rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
 551 out:
 552         return err;
 553 }
 554
 555 void __init ipv6_addr_label_rtnl_register(void)
 556 {
 557         __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
 558         __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
 559         __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
 560 }
 561