1 /* 2 * Anycast support for IPv6 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * David L Stevens (dlstevens@us.ibm.com) 7 * 8 * based heavily on net/ipv6/mcast.c 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 #include <linux/capability.h> 17 #include <linux/module.h> 18 #include <linux/errno.h> 19 #include <linux/types.h> 20 #include <linux/random.h> 21 #include <linux/string.h> 22 #include <linux/socket.h> 23 #include <linux/sockios.h> 24 #include <linux/net.h> 25 #include <linux/in6.h> 26 #include <linux/netdevice.h> 27 #include <linux/if_arp.h> 28 #include <linux/route.h> 29 #include <linux/init.h> 30 #include <linux/proc_fs.h> 31 #include <linux/seq_file.h> 32 33 #include <net/net_namespace.h> 34 #include <net/sock.h> 35 #include <net/snmp.h> 36 37 #include <net/ipv6.h> 38 #include <net/protocol.h> 39 #include <net/if_inet6.h> 40 #include <net/ndisc.h> 41 #include <net/addrconf.h> 42 #include <net/ip6_route.h> 43 44 #include <net/checksum.h> 45 46 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr); 47 48 /* Big ac list lock for all the sockets */ 49 static DEFINE_RWLOCK(ipv6_sk_ac_lock); 50 51 static int 52 ip6_onlink(struct in6_addr *addr, struct net_device *dev) 53 { 54 struct inet6_dev *idev; 55 struct inet6_ifaddr *ifa; 56 int onlink; 57 58 onlink = 0; 59 rcu_read_lock(); 60 idev = __in6_dev_get(dev); 61 if (idev) { 62 read_lock_bh(&idev->lock); 63 for (ifa=idev->addr_list; ifa; ifa=ifa->if_next) { 64 onlink = ipv6_prefix_equal(addr, &ifa->addr, 65 ifa->prefix_len); 66 if (onlink) 67 break; 68 } 69 read_unlock_bh(&idev->lock); 70 } 71 rcu_read_unlock(); 72 return onlink; 73 } 74 75 /* 76 * socket join an anycast group 77 */ 78 79 int ipv6_sock_ac_join(struct sock *sk, int ifindex, struct in6_addr *addr) 80 { 81 struct ipv6_pinfo *np = inet6_sk(sk); 82 struct net_device *dev = NULL; 83 struct inet6_dev *idev; 84 struct ipv6_ac_socklist *pac; 85 int ishost = !ipv6_devconf.forwarding; 86 int err = 0; 87 88 if (!capable(CAP_NET_ADMIN)) 89 return -EPERM; 90 if (ipv6_addr_is_multicast(addr)) 91 return -EINVAL; 92 if (ipv6_chk_addr(&init_net, addr, NULL, 0)) 93 return -EINVAL; 94 95 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 96 if (pac == NULL) 97 return -ENOMEM; 98 pac->acl_next = NULL; 99 ipv6_addr_copy(&pac->acl_addr, addr); 100 101 if (ifindex == 0) { 102 struct rt6_info *rt; 103 104 rt = rt6_lookup(addr, NULL, 0, 0); 105 if (rt) { 106 dev = rt->rt6i_dev; 107 dev_hold(dev); 108 dst_release(&rt->u.dst); 109 } else if (ishost) { 110 err = -EADDRNOTAVAIL; 111 goto out_free_pac; 112 } else { 113 /* router, no matching interface: just pick one */ 114 115 dev = dev_get_by_flags(&init_net, IFF_UP, IFF_UP|IFF_LOOPBACK); 116 } 117 } else 118 dev = dev_get_by_index(&init_net, ifindex); 119 120 if (dev == NULL) { 121 err = -ENODEV; 122 goto out_free_pac; 123 } 124 125 idev = in6_dev_get(dev); 126 if (!idev) { 127 if (ifindex) 128 err = -ENODEV; 129 else 130 err = -EADDRNOTAVAIL; 131 goto out_dev_put; 132 } 133 /* reset ishost, now that we have a specific device */ 134 ishost = !idev->cnf.forwarding; 135 in6_dev_put(idev); 136 137 pac->acl_ifindex = dev->ifindex; 138 139 /* XXX 140 * For hosts, allow link-local or matching prefix anycasts. 141 * This obviates the need for propagating anycast routes while 142 * still allowing some non-router anycast participation. 143 */ 144 if (!ip6_onlink(addr, dev)) { 145 if (ishost) 146 err = -EADDRNOTAVAIL; 147 if (err) 148 goto out_dev_put; 149 } 150 151 err = ipv6_dev_ac_inc(dev, addr); 152 if (err) 153 goto out_dev_put; 154 155 write_lock_bh(&ipv6_sk_ac_lock); 156 pac->acl_next = np->ipv6_ac_list; 157 np->ipv6_ac_list = pac; 158 write_unlock_bh(&ipv6_sk_ac_lock); 159 160 dev_put(dev); 161 162 return 0; 163 164 out_dev_put: 165 dev_put(dev); 166 out_free_pac: 167 sock_kfree_s(sk, pac, sizeof(*pac)); 168 return err; 169 } 170 171 /* 172 * socket leave an anycast group 173 */ 174 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, struct in6_addr *addr) 175 { 176 struct ipv6_pinfo *np = inet6_sk(sk); 177 struct net_device *dev; 178 struct ipv6_ac_socklist *pac, *prev_pac; 179 180 write_lock_bh(&ipv6_sk_ac_lock); 181 prev_pac = NULL; 182 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 183 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 184 ipv6_addr_equal(&pac->acl_addr, addr)) 185 break; 186 prev_pac = pac; 187 } 188 if (!pac) { 189 write_unlock_bh(&ipv6_sk_ac_lock); 190 return -ENOENT; 191 } 192 if (prev_pac) 193 prev_pac->acl_next = pac->acl_next; 194 else 195 np->ipv6_ac_list = pac->acl_next; 196 197 write_unlock_bh(&ipv6_sk_ac_lock); 198 199 dev = dev_get_by_index(&init_net, pac->acl_ifindex); 200 if (dev) { 201 ipv6_dev_ac_dec(dev, &pac->acl_addr); 202 dev_put(dev); 203 } 204 sock_kfree_s(sk, pac, sizeof(*pac)); 205 return 0; 206 } 207 208 void ipv6_sock_ac_close(struct sock *sk) 209 { 210 struct ipv6_pinfo *np = inet6_sk(sk); 211 struct net_device *dev = NULL; 212 struct ipv6_ac_socklist *pac; 213 int prev_index; 214 215 write_lock_bh(&ipv6_sk_ac_lock); 216 pac = np->ipv6_ac_list; 217 np->ipv6_ac_list = NULL; 218 write_unlock_bh(&ipv6_sk_ac_lock); 219 220 prev_index = 0; 221 while (pac) { 222 struct ipv6_ac_socklist *next = pac->acl_next; 223 224 if (pac->acl_ifindex != prev_index) { 225 if (dev) 226 dev_put(dev); 227 dev = dev_get_by_index(&init_net, pac->acl_ifindex); 228 prev_index = pac->acl_ifindex; 229 } 230 if (dev) 231 ipv6_dev_ac_dec(dev, &pac->acl_addr); 232 sock_kfree_s(sk, pac, sizeof(*pac)); 233 pac = next; 234 } 235 if (dev) 236 dev_put(dev); 237 } 238 239 #if 0 240 /* The function is not used, which is funny. Apparently, author 241 * supposed to use it to filter out datagrams inside udp/raw but forgot. 242 * 243 * It is OK, anycasts are not special comparing to delivery to unicasts. 244 */ 245 246 int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex) 247 { 248 struct ipv6_ac_socklist *pac; 249 struct ipv6_pinfo *np = inet6_sk(sk); 250 int found; 251 252 found = 0; 253 read_lock(&ipv6_sk_ac_lock); 254 for (pac=np->ipv6_ac_list; pac; pac=pac->acl_next) { 255 if (ifindex && pac->acl_ifindex != ifindex) 256 continue; 257 found = ipv6_addr_equal(&pac->acl_addr, addr); 258 if (found) 259 break; 260 } 261 read_unlock(&ipv6_sk_ac_lock); 262 263 return found; 264 } 265 266 #endif 267 268 static void aca_put(struct ifacaddr6 *ac) 269 { 270 if (atomic_dec_and_test(&ac->aca_refcnt)) { 271 in6_dev_put(ac->aca_idev); 272 dst_release(&ac->aca_rt->u.dst); 273 kfree(ac); 274 } 275 } 276 277 /* 278 * device anycast group inc (add if not found) 279 */ 280 int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr) 281 { 282 struct ifacaddr6 *aca; 283 struct inet6_dev *idev; 284 struct rt6_info *rt; 285 int err; 286 287 idev = in6_dev_get(dev); 288 289 if (idev == NULL) 290 return -EINVAL; 291 292 write_lock_bh(&idev->lock); 293 if (idev->dead) { 294 err = -ENODEV; 295 goto out; 296 } 297 298 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 299 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 300 aca->aca_users++; 301 err = 0; 302 goto out; 303 } 304 } 305 306 /* 307 * not found: create a new one. 308 */ 309 310 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); 311 312 if (aca == NULL) { 313 err = -ENOMEM; 314 goto out; 315 } 316 317 rt = addrconf_dst_alloc(idev, addr, 1); 318 if (IS_ERR(rt)) { 319 kfree(aca); 320 err = PTR_ERR(rt); 321 goto out; 322 } 323 324 ipv6_addr_copy(&aca->aca_addr, addr); 325 aca->aca_idev = idev; 326 aca->aca_rt = rt; 327 aca->aca_users = 1; 328 /* aca_tstamp should be updated upon changes */ 329 aca->aca_cstamp = aca->aca_tstamp = jiffies; 330 atomic_set(&aca->aca_refcnt, 2); 331 spin_lock_init(&aca->aca_lock); 332 333 aca->aca_next = idev->ac_list; 334 idev->ac_list = aca; 335 write_unlock_bh(&idev->lock); 336 337 ip6_ins_rt(rt); 338 339 addrconf_join_solict(dev, &aca->aca_addr); 340 341 aca_put(aca); 342 return 0; 343 out: 344 write_unlock_bh(&idev->lock); 345 in6_dev_put(idev); 346 return err; 347 } 348 349 /* 350 * device anycast group decrement 351 */ 352 int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr) 353 { 354 struct ifacaddr6 *aca, *prev_aca; 355 356 write_lock_bh(&idev->lock); 357 prev_aca = NULL; 358 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 359 if (ipv6_addr_equal(&aca->aca_addr, addr)) 360 break; 361 prev_aca = aca; 362 } 363 if (!aca) { 364 write_unlock_bh(&idev->lock); 365 return -ENOENT; 366 } 367 if (--aca->aca_users > 0) { 368 write_unlock_bh(&idev->lock); 369 return 0; 370 } 371 if (prev_aca) 372 prev_aca->aca_next = aca->aca_next; 373 else 374 idev->ac_list = aca->aca_next; 375 write_unlock_bh(&idev->lock); 376 addrconf_leave_solict(idev, &aca->aca_addr); 377 378 dst_hold(&aca->aca_rt->u.dst); 379 ip6_del_rt(aca->aca_rt); 380 381 aca_put(aca); 382 return 0; 383 } 384 385 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr) 386 { 387 int ret; 388 struct inet6_dev *idev = in6_dev_get(dev); 389 if (idev == NULL) 390 return -ENODEV; 391 ret = __ipv6_dev_ac_dec(idev, addr); 392 in6_dev_put(idev); 393 return ret; 394 } 395 396 /* 397 * check if the interface has this anycast address 398 */ 399 static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr) 400 { 401 struct inet6_dev *idev; 402 struct ifacaddr6 *aca; 403 404 idev = in6_dev_get(dev); 405 if (idev) { 406 read_lock_bh(&idev->lock); 407 for (aca = idev->ac_list; aca; aca = aca->aca_next) 408 if (ipv6_addr_equal(&aca->aca_addr, addr)) 409 break; 410 read_unlock_bh(&idev->lock); 411 in6_dev_put(idev); 412 return aca != NULL; 413 } 414 return 0; 415 } 416 417 /* 418 * check if given interface (or any, if dev==0) has this anycast address 419 */ 420 int ipv6_chk_acast_addr(struct net_device *dev, struct in6_addr *addr) 421 { 422 int found = 0; 423 424 if (dev) 425 return ipv6_chk_acast_dev(dev, addr); 426 read_lock(&dev_base_lock); 427 for_each_netdev(&init_net, dev) 428 if (ipv6_chk_acast_dev(dev, addr)) { 429 found = 1; 430 break; 431 } 432 read_unlock(&dev_base_lock); 433 return found; 434 } 435 436 437 #ifdef CONFIG_PROC_FS 438 struct ac6_iter_state { 439 struct net_device *dev; 440 struct inet6_dev *idev; 441 }; 442 443 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 444 445 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 446 { 447 struct ifacaddr6 *im = NULL; 448 struct ac6_iter_state *state = ac6_seq_private(seq); 449 450 state->idev = NULL; 451 for_each_netdev(&init_net, state->dev) { 452 struct inet6_dev *idev; 453 idev = in6_dev_get(state->dev); 454 if (!idev) 455 continue; 456 read_lock_bh(&idev->lock); 457 im = idev->ac_list; 458 if (im) { 459 state->idev = idev; 460 break; 461 } 462 read_unlock_bh(&idev->lock); 463 in6_dev_put(idev); 464 } 465 return im; 466 } 467 468 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 469 { 470 struct ac6_iter_state *state = ac6_seq_private(seq); 471 472 im = im->aca_next; 473 while (!im) { 474 if (likely(state->idev != NULL)) { 475 read_unlock_bh(&state->idev->lock); 476 in6_dev_put(state->idev); 477 } 478 state->dev = next_net_device(state->dev); 479 if (!state->dev) { 480 state->idev = NULL; 481 break; 482 } 483 state->idev = in6_dev_get(state->dev); 484 if (!state->idev) 485 continue; 486 read_lock_bh(&state->idev->lock); 487 im = state->idev->ac_list; 488 } 489 return im; 490 } 491 492 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 493 { 494 struct ifacaddr6 *im = ac6_get_first(seq); 495 if (im) 496 while (pos && (im = ac6_get_next(seq, im)) != NULL) 497 --pos; 498 return pos ? NULL : im; 499 } 500 501 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 502 __acquires(dev_base_lock) 503 { 504 read_lock(&dev_base_lock); 505 return ac6_get_idx(seq, *pos); 506 } 507 508 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 509 { 510 struct ifacaddr6 *im; 511 im = ac6_get_next(seq, v); 512 ++*pos; 513 return im; 514 } 515 516 static void ac6_seq_stop(struct seq_file *seq, void *v) 517 __releases(dev_base_lock) 518 { 519 struct ac6_iter_state *state = ac6_seq_private(seq); 520 if (likely(state->idev != NULL)) { 521 read_unlock_bh(&state->idev->lock); 522 in6_dev_put(state->idev); 523 } 524 read_unlock(&dev_base_lock); 525 } 526 527 static int ac6_seq_show(struct seq_file *seq, void *v) 528 { 529 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 530 struct ac6_iter_state *state = ac6_seq_private(seq); 531 532 seq_printf(seq, 533 "%-4d %-15s " NIP6_SEQFMT " %5d\n", 534 state->dev->ifindex, state->dev->name, 535 NIP6(im->aca_addr), 536 im->aca_users); 537 return 0; 538 } 539 540 static const struct seq_operations ac6_seq_ops = { 541 .start = ac6_seq_start, 542 .next = ac6_seq_next, 543 .stop = ac6_seq_stop, 544 .show = ac6_seq_show, 545 }; 546 547 static int ac6_seq_open(struct inode *inode, struct file *file) 548 { 549 return seq_open_private(file, &ac6_seq_ops, 550 sizeof(struct ac6_iter_state)); 551 } 552 553 static const struct file_operations ac6_seq_fops = { 554 .owner = THIS_MODULE, 555 .open = ac6_seq_open, 556 .read = seq_read, 557 .llseek = seq_lseek, 558 .release = seq_release_private, 559 }; 560 561 int __init ac6_proc_init(void) 562 { 563 if (!proc_net_fops_create(&init_net, "anycast6", S_IRUGO, &ac6_seq_fops)) 564 return -ENOMEM; 565 566 return 0; 567 } 568 569 void ac6_proc_exit(void) 570 { 571 proc_net_remove(&init_net, "anycast6"); 572 } 573 #endif 574 575