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  * 2001:10::/28         N/A             7               ORCHID (RFC 4843)
  62  *
  63  * Note: 0xffffffff is used if we do not have any policies.
  64  */
  65
  66 #define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
  67
  68 static const __initdata struct ip6addrlbl_init_table
  69 {
  70         const struct in6_addr *prefix;
  71         int prefixlen;
  72         u32 label;
  73 } ip6addrlbl_init_table[] = {
  74         {       /* ::/0 */
  75                 .prefix = &in6addr_any,
  76                 .label = 1,
  77         },{     /* fc00::/7 */
  78                 .prefix = &(struct in6_addr){{{ 0xfc }}},
  79                 .prefixlen = 7,
  80                 .label = 5,
  81         },{     /* 2002::/16 */
  82                 .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}},
  83                 .prefixlen = 16,
  84                 .label = 2,
  85         },{     /* 2001::/32 */
  86                 .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}},
  87                 .prefixlen = 32,
  88                 .label = 6,
  89         },{     /* 2001:10::/28 */
  90                 .prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}},
  91                 .prefixlen = 28,
  92                 .label = 7,
  93         },{     /* ::ffff:0:0 */
  94                 .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}},
  95                 .prefixlen = 96,
  96                 .label = 4,
  97         },{     /* ::/96 */
  98                 .prefix = &in6addr_any,
  99                 .prefixlen = 96,
 100                 .label = 3,
 101         },{     /* ::1/128 */
 102                 .prefix = &in6addr_loopback,
 103                 .prefixlen = 128,
 104                 .label = 0,
 105         }
 106 };
 107
 108 /* Object management */
 109 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 110 {
 111         kfree(p);
 112 }
 113
 114 static void ip6addrlbl_free_rcu(struct rcu_head *h)
 115 {
 116         ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu));
 117 }
 118
 119 static inline int ip6addrlbl_hold(struct ip6addrlbl_entry *p)
 120 {
 121         return atomic_inc_not_zero(&p->refcnt);
 122 }
 123
 124 static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
 125 {
 126         if (atomic_dec_and_test(&p->refcnt))
 127                 call_rcu(&p->rcu, ip6addrlbl_free_rcu);
 128 }
 129
 130 /* Find label */
 131 static int __ip6addrlbl_match(struct ip6addrlbl_entry *p,
 132                               const struct in6_addr *addr,
 133                               int addrtype, int ifindex)
 134 {
 135         if (p->ifindex && p->ifindex != ifindex)
 136                 return 0;
 137         if (p->addrtype && p->addrtype != addrtype)
 138                 return 0;
 139         if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
 140                 return 0;
 141         return 1;
 142 }
 143
 144 static struct ip6addrlbl_entry *__ipv6_addr_label(const struct in6_addr *addr,
 145                                                   int type, int ifindex)
 146 {
 147         struct hlist_node *pos;
 148         struct ip6addrlbl_entry *p;
 149         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 150                 if (__ip6addrlbl_match(p, addr, type, ifindex))
 151                         return p;
 152         }
 153         return NULL;
 154 }
 155
 156 u32 ipv6_addr_label(const struct in6_addr *addr, int type, int ifindex)
 157 {
 158         u32 label;
 159         struct ip6addrlbl_entry *p;
 160
 161         type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
 162
 163         rcu_read_lock();
 164         p = __ipv6_addr_label(addr, type, ifindex);
 165         label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
 166         rcu_read_unlock();
 167
 168         ADDRLABEL(KERN_DEBUG "%s(addr=" NIP6_FMT ", type=%d, ifindex=%d) => %08x\n",
 169                         __func__,
 170                         NIP6(*addr), type, ifindex,
 171                         label);
 172
 173         return label;
 174 }
 175
 176 /* allocate one entry */
 177 static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
 178                                                  int prefixlen, int ifindex,
 179                                                  u32 label)
 180 {
 181         struct ip6addrlbl_entry *newp;
 182         int addrtype;
 183
 184         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u)\n",
 185                         __func__,
 186                         NIP6(*prefix), prefixlen,
 187                         ifindex,
 188                         (unsigned int)label);
 189
 190         addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
 191
 192         switch (addrtype) {
 193         case IPV6_ADDR_MAPPED:
 194                 if (prefixlen > 96)
 195                         return ERR_PTR(-EINVAL);
 196                 if (prefixlen < 96)
 197                         addrtype = 0;
 198                 break;
 199         case IPV6_ADDR_COMPATv4:
 200                 if (prefixlen != 96)
 201                         addrtype = 0;
 202                 break;
 203         case IPV6_ADDR_LOOPBACK:
 204                 if (prefixlen != 128)
 205                         addrtype = 0;
 206                 break;
 207         }
 208
 209         newp = kmalloc(sizeof(*newp), GFP_KERNEL);
 210         if (!newp)
 211                 return ERR_PTR(-ENOMEM);
 212
 213         ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
 214         newp->prefixlen = prefixlen;
 215         newp->ifindex = ifindex;
 216         newp->addrtype = addrtype;
 217         newp->label = label;
 218         INIT_HLIST_NODE(&newp->list);
 219         atomic_set(&newp->refcnt, 1);
 220         return newp;
 221 }
 222
 223 /* add a label */
 224 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
 225 {
 226         int ret = 0;
 227
 228         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",
 229                         __func__,
 230                         newp, replace);
 231
 232         if (hlist_empty(&ip6addrlbl_table.head)) {
 233                 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
 234         } else {
 235                 struct hlist_node *pos, *n;
 236                 struct ip6addrlbl_entry *p = NULL;
 237                 hlist_for_each_entry_safe(p, pos, n,
 238                                           &ip6addrlbl_table.head, list) {
 239                         if (p->prefixlen == newp->prefixlen &&
 240                             p->ifindex == newp->ifindex &&
 241                             ipv6_addr_equal(&p->prefix, &newp->prefix)) {
 242                                 if (!replace) {
 243                                         ret = -EEXIST;
 244                                         goto out;
 245                                 }
 246                                 hlist_replace_rcu(&p->list, &newp->list);
 247                                 ip6addrlbl_put(p);
 248                                 goto out;
 249                         } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
 250                                    (p->prefixlen < newp->prefixlen)) {
 251                                 hlist_add_before_rcu(&newp->list, &p->list);
 252                                 goto out;
 253                         }
 254                 }
 255                 hlist_add_after_rcu(&p->list, &newp->list);
 256         }
 257 out:
 258         if (!ret)
 259                 ip6addrlbl_table.seq++;
 260         return ret;
 261 }
 262
 263 /* add a label */
 264 static int ip6addrlbl_add(const struct in6_addr *prefix, int prefixlen,
 265                           int ifindex, u32 label, int replace)
 266 {
 267         struct ip6addrlbl_entry *newp;
 268         int ret = 0;
 269
 270         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
 271                         __func__,
 272                         NIP6(*prefix), prefixlen,
 273                         ifindex,
 274                         (unsigned int)label,
 275                         replace);
 276
 277         newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
 278         if (IS_ERR(newp))
 279                 return PTR_ERR(newp);
 280         spin_lock(&ip6addrlbl_table.lock);
 281         ret = __ip6addrlbl_add(newp, replace);
 282         spin_unlock(&ip6addrlbl_table.lock);
 283         if (ret)
 284                 ip6addrlbl_free(newp);
 285         return ret;
 286 }
 287
 288 /* remove a label */
 289 static int __ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 290                             int ifindex)
 291 {
 292         struct ip6addrlbl_entry *p = NULL;
 293         struct hlist_node *pos, *n;
 294         int ret = -ESRCH;
 295
 296         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 297                         __func__,
 298                         NIP6(*prefix), prefixlen,
 299                         ifindex);
 300
 301         hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) {
 302                 if (p->prefixlen == prefixlen &&
 303                     p->ifindex == ifindex &&
 304                     ipv6_addr_equal(&p->prefix, prefix)) {
 305                         hlist_del_rcu(&p->list);
 306                         ip6addrlbl_put(p);
 307                         ret = 0;
 308                         break;
 309                 }
 310         }
 311         return ret;
 312 }
 313
 314 static int ip6addrlbl_del(const struct in6_addr *prefix, int prefixlen,
 315                           int ifindex)
 316 {
 317         struct in6_addr prefix_buf;
 318         int ret;
 319
 320         ADDRLABEL(KERN_DEBUG "%s(prefix=" NIP6_FMT ", prefixlen=%d, ifindex=%d)\n",
 321                         __func__,
 322                         NIP6(*prefix), prefixlen,
 323                         ifindex);
 324
 325         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
 326         spin_lock(&ip6addrlbl_table.lock);
 327         ret = __ip6addrlbl_del(&prefix_buf, prefixlen, ifindex);
 328         spin_unlock(&ip6addrlbl_table.lock);
 329         return ret;
 330 }
 331
 332 /* add default label */
 333 static __init int ip6addrlbl_init(void)
 334 {
 335         int err = 0;
 336         int i;
 337
 338         ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
 339
 340         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 341                 int ret = ip6addrlbl_add(ip6addrlbl_init_table[i].prefix,
 342                                          ip6addrlbl_init_table[i].prefixlen,
 343                                          0,
 344                                          ip6addrlbl_init_table[i].label, 0);
 345                 /* XXX: should we free all rules when we catch an error? */
 346                 if (ret && (!err || err != -ENOMEM))
 347                         err = ret;
 348         }
 349         return err;
 350 }
 351
 352 int __init ipv6_addr_label_init(void)
 353 {
 354         spin_lock_init(&ip6addrlbl_table.lock);
 355
 356         return ip6addrlbl_init();
 357 }
 358
 359 static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 360         [IFAL_ADDRESS]          = { .len = sizeof(struct in6_addr), },
 361         [IFAL_LABEL]            = { .len = sizeof(u32), },
 362 };
 363
 364 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 365                              void *arg)
 366 {
 367         struct net *net = skb->sk->sk_net;
 368         struct ifaddrlblmsg *ifal;
 369         struct nlattr *tb[IFAL_MAX+1];
 370         struct in6_addr *pfx;
 371         u32 label;
 372         int err = 0;
 373
 374         if (net != &init_net)
 375                 return 0;
 376
 377         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 378         if (err < 0)
 379                 return err;
 380
 381         ifal = nlmsg_data(nlh);
 382
 383         if (ifal->ifal_family != AF_INET6 ||
 384             ifal->ifal_prefixlen > 128)
 385                 return -EINVAL;
 386
 387         if (ifal->ifal_index &&
 388             !__dev_get_by_index(&init_net, ifal->ifal_index))
 389                 return -EINVAL;
 390
 391         if (!tb[IFAL_ADDRESS])
 392                 return -EINVAL;
 393
 394         pfx = nla_data(tb[IFAL_ADDRESS]);
 395         if (!pfx)
 396                 return -EINVAL;
 397
 398         if (!tb[IFAL_LABEL])
 399                 return -EINVAL;
 400         label = nla_get_u32(tb[IFAL_LABEL]);
 401         if (label == IPV6_ADDR_LABEL_DEFAULT)
 402                 return -EINVAL;
 403
 404         switch(nlh->nlmsg_type) {
 405         case RTM_NEWADDRLABEL:
 406                 err = ip6addrlbl_add(pfx, ifal->ifal_prefixlen,
 407                                      ifal->ifal_index, label,
 408                                      nlh->nlmsg_flags & NLM_F_REPLACE);
 409                 break;
 410         case RTM_DELADDRLABEL:
 411                 err = ip6addrlbl_del(pfx, ifal->ifal_prefixlen,
 412                                      ifal->ifal_index);
 413                 break;
 414         default:
 415                 err = -EOPNOTSUPP;
 416         }
 417         return err;
 418 }
 419
 420 static inline void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
 421                                      int prefixlen, int ifindex, u32 lseq)
 422 {
 423         struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
 424         ifal->ifal_family = AF_INET6;
 425         ifal->ifal_prefixlen = prefixlen;
 426         ifal->ifal_flags = 0;
 427         ifal->ifal_index = ifindex;
 428         ifal->ifal_seq = lseq;
 429 };
 430
 431 static int ip6addrlbl_fill(struct sk_buff *skb,
 432                            struct ip6addrlbl_entry *p,
 433                            u32 lseq,
 434                            u32 pid, u32 seq, int event,
 435                            unsigned int flags)
 436 {
 437         struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event,
 438                                          sizeof(struct ifaddrlblmsg), flags);
 439         if (!nlh)
 440                 return -EMSGSIZE;
 441
 442         ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
 443
 444         if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 ||
 445             nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
 446                 nlmsg_cancel(skb, nlh);
 447                 return -EMSGSIZE;
 448         }
 449
 450         return nlmsg_end(skb, nlh);
 451 }
 452
 453 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 454 {
 455         struct net *net = skb->sk->sk_net;
 456         struct ip6addrlbl_entry *p;
 457         struct hlist_node *pos;
 458         int idx = 0, s_idx = cb->args[0];
 459         int err;
 460
 461         if (net != &init_net)
 462                 return 0;
 463
 464         rcu_read_lock();
 465         hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 466                 if (idx >= s_idx) {
 467                         if ((err = ip6addrlbl_fill(skb, p,
 468                                                    ip6addrlbl_table.seq,
 469                                                    NETLINK_CB(cb->skb).pid,
 470                                                    cb->nlh->nlmsg_seq,
 471                                                    RTM_NEWADDRLABEL,
 472                                                    NLM_F_MULTI)) <= 0)
 473                                 break;
 474                 }
 475                 idx++;
 476         }
 477         rcu_read_unlock();
 478         cb->args[0] = idx;
 479         return skb->len;
 480 }
 481
 482 static inline int ip6addrlbl_msgsize(void)
 483 {
 484         return (NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
 485                 + nla_total_size(16)    /* IFAL_ADDRESS */
 486                 + nla_total_size(4)     /* IFAL_LABEL */
 487         );
 488 }
 489
 490 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 491                           void *arg)
 492 {
 493         struct net *net = in_skb->sk->sk_net;
 494         struct ifaddrlblmsg *ifal;
 495         struct nlattr *tb[IFAL_MAX+1];
 496         struct in6_addr *addr;
 497         u32 lseq;
 498         int err = 0;
 499         struct ip6addrlbl_entry *p;
 500         struct sk_buff *skb;
 501
 502         if (net != &init_net)
 503                 return 0;
 504
 505         err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 506         if (err < 0)
 507                 return err;
 508
 509         ifal = nlmsg_data(nlh);
 510
 511         if (ifal->ifal_family != AF_INET6 ||
 512             ifal->ifal_prefixlen != 128)
 513                 return -EINVAL;
 514
 515         if (ifal->ifal_index &&
 516             !__dev_get_by_index(&init_net, ifal->ifal_index))
 517                 return -EINVAL;
 518
 519         if (!tb[IFAL_ADDRESS])
 520                 return -EINVAL;
 521
 522         addr = nla_data(tb[IFAL_ADDRESS]);
 523         if (!addr)
 524                 return -EINVAL;
 525
 526         rcu_read_lock();
 527         p = __ipv6_addr_label(addr, ipv6_addr_type(addr), ifal->ifal_index);
 528         if (p && ip6addrlbl_hold(p))
 529                 p = NULL;
 530         lseq = ip6addrlbl_table.seq;
 531         rcu_read_unlock();
 532
 533         if (!p) {
 534                 err = -ESRCH;
 535                 goto out;
 536         }
 537
 538         if (!(skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL))) {
 539                 ip6addrlbl_put(p);
 540                 return -ENOBUFS;
 541         }
 542
 543         err = ip6addrlbl_fill(skb, p, lseq,
 544                               NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 545                               RTM_NEWADDRLABEL, 0);
 546
 547         ip6addrlbl_put(p);
 548
 549         if (err < 0) {
 550                 WARN_ON(err == -EMSGSIZE);
 551                 kfree_skb(skb);
 552                 goto out;
 553         }
 554
 555         err = rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
 556 out:
 557         return err;
 558 }
 559
 560 void __init ipv6_addr_label_rtnl_register(void)
 561 {
 562         __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel, NULL);
 563         __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, NULL);
 564         __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, ip6addrlbl_dump);
 565 }
 566