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 return read_pnet(&lbl->lbl_net); 57 } 58 59 /* 60 * Default policy table (RFC3484 + extensions) 61 * 62 * prefix addr_type label 63 * ------------------------------------------------------------------------- 64 * ::1/128 LOOPBACK 0 65 * ::/0 N/A 1 66 * 2002::/16 N/A 2 67 * ::/96 COMPATv4 3 68 * ::ffff:0:0/96 V4MAPPED 4 69 * fc00::/7 N/A 5 ULA (RFC 4193) 70 * 2001::/32 N/A 6 Teredo (RFC 4380) 71 * 2001:10::/28 N/A 7 ORCHID (RFC 4843) 72 * 73 * Note: 0xffffffff is used if we do not have any policies. 74 */ 75 76 #define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL 77 78 static const __net_initdata struct ip6addrlbl_init_table 79 { 80 const struct in6_addr *prefix; 81 int prefixlen; 82 u32 label; 83 } ip6addrlbl_init_table[] = { 84 { /* ::/0 */ 85 .prefix = &in6addr_any, 86 .label = 1, 87 },{ /* fc00::/7 */ 88 .prefix = &(struct in6_addr){{{ 0xfc }}}, 89 .prefixlen = 7, 90 .label = 5, 91 },{ /* 2002::/16 */ 92 .prefix = &(struct in6_addr){{{ 0x20, 0x02 }}}, 93 .prefixlen = 16, 94 .label = 2, 95 },{ /* 2001::/32 */ 96 .prefix = &(struct in6_addr){{{ 0x20, 0x01 }}}, 97 .prefixlen = 32, 98 .label = 6, 99 },{ /* 2001:10::/28 */ 100 .prefix = &(struct in6_addr){{{ 0x20, 0x01, 0x00, 0x10 }}}, 101 .prefixlen = 28, 102 .label = 7, 103 },{ /* ::ffff:0:0 */ 104 .prefix = &(struct in6_addr){{{ [10] = 0xff, [11] = 0xff }}}, 105 .prefixlen = 96, 106 .label = 4, 107 },{ /* ::/96 */ 108 .prefix = &in6addr_any, 109 .prefixlen = 96, 110 .label = 3, 111 },{ /* ::1/128 */ 112 .prefix = &in6addr_loopback, 113 .prefixlen = 128, 114 .label = 0, 115 } 116 }; 117 118 /* Object management */ 119 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p) 120 { 121 #ifdef CONFIG_NET_NS 122 release_net(p->lbl_net); 123 #endif 124 kfree(p); 125 } 126 127 static void ip6addrlbl_free_rcu(struct rcu_head *h) 128 { 129 ip6addrlbl_free(container_of(h, struct ip6addrlbl_entry, rcu)); 130 } 131 132 static bool ip6addrlbl_hold(struct ip6addrlbl_entry *p) 133 { 134 return atomic_inc_not_zero(&p->refcnt); 135 } 136 137 static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p) 138 { 139 if (atomic_dec_and_test(&p->refcnt)) 140 call_rcu(&p->rcu, ip6addrlbl_free_rcu); 141 } 142 143 /* Find label */ 144 static bool __ip6addrlbl_match(struct net *net, 145 const struct ip6addrlbl_entry *p, 146 const struct in6_addr *addr, 147 int addrtype, int ifindex) 148 { 149 if (!net_eq(ip6addrlbl_net(p), net)) 150 return false; 151 if (p->ifindex && p->ifindex != ifindex) 152 return false; 153 if (p->addrtype && p->addrtype != addrtype) 154 return false; 155 if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen)) 156 return false; 157 return true; 158 } 159 160 static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net, 161 const struct in6_addr *addr, 162 int type, int ifindex) 163 { 164 struct hlist_node *pos; 165 struct ip6addrlbl_entry *p; 166 hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) { 167 if (__ip6addrlbl_match(net, p, addr, type, ifindex)) 168 return p; 169 } 170 return NULL; 171 } 172 173 u32 ipv6_addr_label(struct net *net, 174 const struct in6_addr *addr, int type, int ifindex) 175 { 176 u32 label; 177 struct ip6addrlbl_entry *p; 178 179 type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK; 180 181 rcu_read_lock(); 182 p = __ipv6_addr_label(net, addr, type, ifindex); 183 label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT; 184 rcu_read_unlock(); 185 186 ADDRLABEL(KERN_DEBUG "%s(addr=%pI6, type=%d, ifindex=%d) => %08x\n", 187 __func__, addr, type, ifindex, label); 188 189 return label; 190 } 191 192 /* allocate one entry */ 193 static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net, 194 const struct in6_addr *prefix, 195 int prefixlen, int ifindex, 196 u32 label) 197 { 198 struct ip6addrlbl_entry *newp; 199 int addrtype; 200 201 ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n", 202 __func__, prefix, prefixlen, ifindex, (unsigned int)label); 203 204 addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK); 205 206 switch (addrtype) { 207 case IPV6_ADDR_MAPPED: 208 if (prefixlen > 96) 209 return ERR_PTR(-EINVAL); 210 if (prefixlen < 96) 211 addrtype = 0; 212 break; 213 case IPV6_ADDR_COMPATv4: 214 if (prefixlen != 96) 215 addrtype = 0; 216 break; 217 case IPV6_ADDR_LOOPBACK: 218 if (prefixlen != 128) 219 addrtype = 0; 220 break; 221 } 222 223 newp = kmalloc(sizeof(*newp), GFP_KERNEL); 224 if (!newp) 225 return ERR_PTR(-ENOMEM); 226 227 ipv6_addr_prefix(&newp->prefix, prefix, prefixlen); 228 newp->prefixlen = prefixlen; 229 newp->ifindex = ifindex; 230 newp->addrtype = addrtype; 231 newp->label = label; 232 INIT_HLIST_NODE(&newp->list); 233 #ifdef CONFIG_NET_NS 234 newp->lbl_net = hold_net(net); 235 #endif 236 atomic_set(&newp->refcnt, 1); 237 return newp; 238 } 239 240 /* add a label */ 241 static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace) 242 { 243 int ret = 0; 244 245 ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n", 246 __func__, 247 newp, replace); 248 249 if (hlist_empty(&ip6addrlbl_table.head)) { 250 hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head); 251 } else { 252 struct hlist_node *pos, *n; 253 struct ip6addrlbl_entry *p = NULL; 254 hlist_for_each_entry_safe(p, pos, n, 255 &ip6addrlbl_table.head, list) { 256 if (p->prefixlen == newp->prefixlen && 257 net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) && 258 p->ifindex == newp->ifindex && 259 ipv6_addr_equal(&p->prefix, &newp->prefix)) { 260 if (!replace) { 261 ret = -EEXIST; 262 goto out; 263 } 264 hlist_replace_rcu(&p->list, &newp->list); 265 ip6addrlbl_put(p); 266 goto out; 267 } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) || 268 (p->prefixlen < newp->prefixlen)) { 269 hlist_add_before_rcu(&newp->list, &p->list); 270 goto out; 271 } 272 } 273 hlist_add_after_rcu(&p->list, &newp->list); 274 } 275 out: 276 if (!ret) 277 ip6addrlbl_table.seq++; 278 return ret; 279 } 280 281 /* add a label */ 282 static int ip6addrlbl_add(struct net *net, 283 const struct in6_addr *prefix, int prefixlen, 284 int ifindex, u32 label, int replace) 285 { 286 struct ip6addrlbl_entry *newp; 287 int ret = 0; 288 289 ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n", 290 __func__, prefix, prefixlen, ifindex, (unsigned int)label, 291 replace); 292 293 newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label); 294 if (IS_ERR(newp)) 295 return PTR_ERR(newp); 296 spin_lock(&ip6addrlbl_table.lock); 297 ret = __ip6addrlbl_add(newp, replace); 298 spin_unlock(&ip6addrlbl_table.lock); 299 if (ret) 300 ip6addrlbl_free(newp); 301 return ret; 302 } 303 304 /* remove a label */ 305 static int __ip6addrlbl_del(struct net *net, 306 const struct in6_addr *prefix, int prefixlen, 307 int ifindex) 308 { 309 struct ip6addrlbl_entry *p = NULL; 310 struct hlist_node *pos, *n; 311 int ret = -ESRCH; 312 313 ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n", 314 __func__, prefix, prefixlen, ifindex); 315 316 hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) { 317 if (p->prefixlen == prefixlen && 318 net_eq(ip6addrlbl_net(p), net) && 319 p->ifindex == ifindex && 320 ipv6_addr_equal(&p->prefix, prefix)) { 321 hlist_del_rcu(&p->list); 322 ip6addrlbl_put(p); 323 ret = 0; 324 break; 325 } 326 } 327 return ret; 328 } 329 330 static int ip6addrlbl_del(struct net *net, 331 const struct in6_addr *prefix, int prefixlen, 332 int ifindex) 333 { 334 struct in6_addr prefix_buf; 335 int ret; 336 337 ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n", 338 __func__, prefix, prefixlen, ifindex); 339 340 ipv6_addr_prefix(&prefix_buf, prefix, prefixlen); 341 spin_lock(&ip6addrlbl_table.lock); 342 ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex); 343 spin_unlock(&ip6addrlbl_table.lock); 344 return ret; 345 } 346 347 /* add default label */ 348 static int __net_init ip6addrlbl_net_init(struct net *net) 349 { 350 int err = 0; 351 int i; 352 353 ADDRLABEL(KERN_DEBUG "%s\n", __func__); 354 355 for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) { 356 int ret = ip6addrlbl_add(net, 357 ip6addrlbl_init_table[i].prefix, 358 ip6addrlbl_init_table[i].prefixlen, 359 0, 360 ip6addrlbl_init_table[i].label, 0); 361 /* XXX: should we free all rules when we catch an error? */ 362 if (ret && (!err || err != -ENOMEM)) 363 err = ret; 364 } 365 return err; 366 } 367 368 static void __net_exit ip6addrlbl_net_exit(struct net *net) 369 { 370 struct ip6addrlbl_entry *p = NULL; 371 struct hlist_node *pos, *n; 372 373 /* Remove all labels belonging to the exiting net */ 374 spin_lock(&ip6addrlbl_table.lock); 375 hlist_for_each_entry_safe(p, pos, n, &ip6addrlbl_table.head, list) { 376 if (net_eq(ip6addrlbl_net(p), net)) { 377 hlist_del_rcu(&p->list); 378 ip6addrlbl_put(p); 379 } 380 } 381 spin_unlock(&ip6addrlbl_table.lock); 382 } 383 384 static struct pernet_operations ipv6_addr_label_ops = { 385 .init = ip6addrlbl_net_init, 386 .exit = ip6addrlbl_net_exit, 387 }; 388 389 int __init ipv6_addr_label_init(void) 390 { 391 spin_lock_init(&ip6addrlbl_table.lock); 392 393 return register_pernet_subsys(&ipv6_addr_label_ops); 394 } 395 396 void ipv6_addr_label_cleanup(void) 397 { 398 unregister_pernet_subsys(&ipv6_addr_label_ops); 399 } 400 401 static const struct nla_policy ifal_policy[IFAL_MAX+1] = { 402 [IFAL_ADDRESS] = { .len = sizeof(struct in6_addr), }, 403 [IFAL_LABEL] = { .len = sizeof(u32), }, 404 }; 405 406 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh, 407 void *arg) 408 { 409 struct net *net = sock_net(skb->sk); 410 struct ifaddrlblmsg *ifal; 411 struct nlattr *tb[IFAL_MAX+1]; 412 struct in6_addr *pfx; 413 u32 label; 414 int err = 0; 415 416 err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy); 417 if (err < 0) 418 return err; 419 420 ifal = nlmsg_data(nlh); 421 422 if (ifal->ifal_family != AF_INET6 || 423 ifal->ifal_prefixlen > 128) 424 return -EINVAL; 425 426 if (!tb[IFAL_ADDRESS]) 427 return -EINVAL; 428 429 pfx = nla_data(tb[IFAL_ADDRESS]); 430 if (!pfx) 431 return -EINVAL; 432 433 if (!tb[IFAL_LABEL]) 434 return -EINVAL; 435 label = nla_get_u32(tb[IFAL_LABEL]); 436 if (label == IPV6_ADDR_LABEL_DEFAULT) 437 return -EINVAL; 438 439 switch(nlh->nlmsg_type) { 440 case RTM_NEWADDRLABEL: 441 if (ifal->ifal_index && 442 !__dev_get_by_index(net, ifal->ifal_index)) 443 return -EINVAL; 444 445 err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen, 446 ifal->ifal_index, label, 447 nlh->nlmsg_flags & NLM_F_REPLACE); 448 break; 449 case RTM_DELADDRLABEL: 450 err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen, 451 ifal->ifal_index); 452 break; 453 default: 454 err = -EOPNOTSUPP; 455 } 456 return err; 457 } 458 459 static void ip6addrlbl_putmsg(struct nlmsghdr *nlh, 460 int prefixlen, int ifindex, u32 lseq) 461 { 462 struct ifaddrlblmsg *ifal = nlmsg_data(nlh); 463 ifal->ifal_family = AF_INET6; 464 ifal->ifal_prefixlen = prefixlen; 465 ifal->ifal_flags = 0; 466 ifal->ifal_index = ifindex; 467 ifal->ifal_seq = lseq; 468 }; 469 470 static int ip6addrlbl_fill(struct sk_buff *skb, 471 struct ip6addrlbl_entry *p, 472 u32 lseq, 473 u32 pid, u32 seq, int event, 474 unsigned int flags) 475 { 476 struct nlmsghdr *nlh = nlmsg_put(skb, pid, seq, event, 477 sizeof(struct ifaddrlblmsg), flags); 478 if (!nlh) 479 return -EMSGSIZE; 480 481 ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq); 482 483 if (nla_put(skb, IFAL_ADDRESS, 16, &p->prefix) < 0 || 484 nla_put_u32(skb, IFAL_LABEL, p->label) < 0) { 485 nlmsg_cancel(skb, nlh); 486 return -EMSGSIZE; 487 } 488 489 return nlmsg_end(skb, nlh); 490 } 491 492 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb) 493 { 494 struct net *net = sock_net(skb->sk); 495 struct ip6addrlbl_entry *p; 496 struct hlist_node *pos; 497 int idx = 0, s_idx = cb->args[0]; 498 int err; 499 500 rcu_read_lock(); 501 hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) { 502 if (idx >= s_idx && 503 net_eq(ip6addrlbl_net(p), net)) { 504 if ((err = ip6addrlbl_fill(skb, p, 505 ip6addrlbl_table.seq, 506 NETLINK_CB(cb->skb).pid, 507 cb->nlh->nlmsg_seq, 508 RTM_NEWADDRLABEL, 509 NLM_F_MULTI)) <= 0) 510 break; 511 } 512 idx++; 513 } 514 rcu_read_unlock(); 515 cb->args[0] = idx; 516 return skb->len; 517 } 518 519 static inline int ip6addrlbl_msgsize(void) 520 { 521 return NLMSG_ALIGN(sizeof(struct ifaddrlblmsg)) 522 + nla_total_size(16) /* IFAL_ADDRESS */ 523 + nla_total_size(4); /* IFAL_LABEL */ 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, 596 NULL, NULL); 597 __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel, 598 NULL, NULL); 599 __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get, 600 ip6addrlbl_dump, NULL); 601 } 602 603