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 52 /* 53 * socket join an anycast group 54 */ 55 56 int ipv6_sock_ac_join(struct sock *sk, int ifindex, struct in6_addr *addr) 57 { 58 struct ipv6_pinfo *np = inet6_sk(sk); 59 struct net_device *dev = NULL; 60 struct inet6_dev *idev; 61 struct ipv6_ac_socklist *pac; 62 struct net *net = sock_net(sk); 63 int ishost = !net->ipv6.devconf_all->forwarding; 64 int err = 0; 65 66 if (!capable(CAP_NET_ADMIN)) 67 return -EPERM; 68 if (ipv6_addr_is_multicast(addr)) 69 return -EINVAL; 70 if (ipv6_chk_addr(net, addr, NULL, 0)) 71 return -EINVAL; 72 73 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 74 if (pac == NULL) 75 return -ENOMEM; 76 pac->acl_next = NULL; 77 ipv6_addr_copy(&pac->acl_addr, addr); 78 79 if (ifindex == 0) { 80 struct rt6_info *rt; 81 82 rt = rt6_lookup(net, addr, NULL, 0, 0); 83 if (rt) { 84 dev = rt->rt6i_dev; 85 dev_hold(dev); 86 dst_release(&rt->u.dst); 87 } else if (ishost) { 88 err = -EADDRNOTAVAIL; 89 goto out_free_pac; 90 } else { 91 /* router, no matching interface: just pick one */ 92 93 dev = dev_get_by_flags(net, IFF_UP, IFF_UP|IFF_LOOPBACK); 94 } 95 } else 96 dev = dev_get_by_index(net, ifindex); 97 98 if (dev == NULL) { 99 err = -ENODEV; 100 goto out_free_pac; 101 } 102 103 idev = in6_dev_get(dev); 104 if (!idev) { 105 if (ifindex) 106 err = -ENODEV; 107 else 108 err = -EADDRNOTAVAIL; 109 goto out_dev_put; 110 } 111 /* reset ishost, now that we have a specific device */ 112 ishost = !idev->cnf.forwarding; 113 in6_dev_put(idev); 114 115 pac->acl_ifindex = dev->ifindex; 116 117 /* XXX 118 * For hosts, allow link-local or matching prefix anycasts. 119 * This obviates the need for propagating anycast routes while 120 * still allowing some non-router anycast participation. 121 */ 122 if (!ipv6_chk_prefix(addr, dev)) { 123 if (ishost) 124 err = -EADDRNOTAVAIL; 125 if (err) 126 goto out_dev_put; 127 } 128 129 err = ipv6_dev_ac_inc(dev, addr); 130 if (err) 131 goto out_dev_put; 132 133 write_lock_bh(&ipv6_sk_ac_lock); 134 pac->acl_next = np->ipv6_ac_list; 135 np->ipv6_ac_list = pac; 136 write_unlock_bh(&ipv6_sk_ac_lock); 137 138 dev_put(dev); 139 140 return 0; 141 142 out_dev_put: 143 dev_put(dev); 144 out_free_pac: 145 sock_kfree_s(sk, pac, sizeof(*pac)); 146 return err; 147 } 148 149 /* 150 * socket leave an anycast group 151 */ 152 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, struct in6_addr *addr) 153 { 154 struct ipv6_pinfo *np = inet6_sk(sk); 155 struct net_device *dev; 156 struct ipv6_ac_socklist *pac, *prev_pac; 157 struct net *net = sock_net(sk); 158 159 write_lock_bh(&ipv6_sk_ac_lock); 160 prev_pac = NULL; 161 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 162 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 163 ipv6_addr_equal(&pac->acl_addr, addr)) 164 break; 165 prev_pac = pac; 166 } 167 if (!pac) { 168 write_unlock_bh(&ipv6_sk_ac_lock); 169 return -ENOENT; 170 } 171 if (prev_pac) 172 prev_pac->acl_next = pac->acl_next; 173 else 174 np->ipv6_ac_list = pac->acl_next; 175 176 write_unlock_bh(&ipv6_sk_ac_lock); 177 178 dev = dev_get_by_index(net, pac->acl_ifindex); 179 if (dev) { 180 ipv6_dev_ac_dec(dev, &pac->acl_addr); 181 dev_put(dev); 182 } 183 sock_kfree_s(sk, pac, sizeof(*pac)); 184 return 0; 185 } 186 187 void ipv6_sock_ac_close(struct sock *sk) 188 { 189 struct ipv6_pinfo *np = inet6_sk(sk); 190 struct net_device *dev = NULL; 191 struct ipv6_ac_socklist *pac; 192 struct net *net = sock_net(sk); 193 int prev_index; 194 195 write_lock_bh(&ipv6_sk_ac_lock); 196 pac = np->ipv6_ac_list; 197 np->ipv6_ac_list = NULL; 198 write_unlock_bh(&ipv6_sk_ac_lock); 199 200 prev_index = 0; 201 while (pac) { 202 struct ipv6_ac_socklist *next = pac->acl_next; 203 204 if (pac->acl_ifindex != prev_index) { 205 if (dev) 206 dev_put(dev); 207 dev = dev_get_by_index(net, pac->acl_ifindex); 208 prev_index = pac->acl_ifindex; 209 } 210 if (dev) 211 ipv6_dev_ac_dec(dev, &pac->acl_addr); 212 sock_kfree_s(sk, pac, sizeof(*pac)); 213 pac = next; 214 } 215 if (dev) 216 dev_put(dev); 217 } 218 219 #if 0 220 /* The function is not used, which is funny. Apparently, author 221 * supposed to use it to filter out datagrams inside udp/raw but forgot. 222 * 223 * It is OK, anycasts are not special comparing to delivery to unicasts. 224 */ 225 226 int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex) 227 { 228 struct ipv6_ac_socklist *pac; 229 struct ipv6_pinfo *np = inet6_sk(sk); 230 int found; 231 232 found = 0; 233 read_lock(&ipv6_sk_ac_lock); 234 for (pac=np->ipv6_ac_list; pac; pac=pac->acl_next) { 235 if (ifindex && pac->acl_ifindex != ifindex) 236 continue; 237 found = ipv6_addr_equal(&pac->acl_addr, addr); 238 if (found) 239 break; 240 } 241 read_unlock(&ipv6_sk_ac_lock); 242 243 return found; 244 } 245 246 #endif 247 248 static void aca_put(struct ifacaddr6 *ac) 249 { 250 if (atomic_dec_and_test(&ac->aca_refcnt)) { 251 in6_dev_put(ac->aca_idev); 252 dst_release(&ac->aca_rt->u.dst); 253 kfree(ac); 254 } 255 } 256 257 /* 258 * device anycast group inc (add if not found) 259 */ 260 int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr) 261 { 262 struct ifacaddr6 *aca; 263 struct inet6_dev *idev; 264 struct rt6_info *rt; 265 int err; 266 267 idev = in6_dev_get(dev); 268 269 if (idev == NULL) 270 return -EINVAL; 271 272 write_lock_bh(&idev->lock); 273 if (idev->dead) { 274 err = -ENODEV; 275 goto out; 276 } 277 278 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 279 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 280 aca->aca_users++; 281 err = 0; 282 goto out; 283 } 284 } 285 286 /* 287 * not found: create a new one. 288 */ 289 290 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); 291 292 if (aca == NULL) { 293 err = -ENOMEM; 294 goto out; 295 } 296 297 rt = addrconf_dst_alloc(idev, addr, 1); 298 if (IS_ERR(rt)) { 299 kfree(aca); 300 err = PTR_ERR(rt); 301 goto out; 302 } 303 304 ipv6_addr_copy(&aca->aca_addr, addr); 305 aca->aca_idev = idev; 306 aca->aca_rt = rt; 307 aca->aca_users = 1; 308 /* aca_tstamp should be updated upon changes */ 309 aca->aca_cstamp = aca->aca_tstamp = jiffies; 310 atomic_set(&aca->aca_refcnt, 2); 311 spin_lock_init(&aca->aca_lock); 312 313 aca->aca_next = idev->ac_list; 314 idev->ac_list = aca; 315 write_unlock_bh(&idev->lock); 316 317 ip6_ins_rt(rt); 318 319 addrconf_join_solict(dev, &aca->aca_addr); 320 321 aca_put(aca); 322 return 0; 323 out: 324 write_unlock_bh(&idev->lock); 325 in6_dev_put(idev); 326 return err; 327 } 328 329 /* 330 * device anycast group decrement 331 */ 332 int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr) 333 { 334 struct ifacaddr6 *aca, *prev_aca; 335 336 write_lock_bh(&idev->lock); 337 prev_aca = NULL; 338 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 339 if (ipv6_addr_equal(&aca->aca_addr, addr)) 340 break; 341 prev_aca = aca; 342 } 343 if (!aca) { 344 write_unlock_bh(&idev->lock); 345 return -ENOENT; 346 } 347 if (--aca->aca_users > 0) { 348 write_unlock_bh(&idev->lock); 349 return 0; 350 } 351 if (prev_aca) 352 prev_aca->aca_next = aca->aca_next; 353 else 354 idev->ac_list = aca->aca_next; 355 write_unlock_bh(&idev->lock); 356 addrconf_leave_solict(idev, &aca->aca_addr); 357 358 dst_hold(&aca->aca_rt->u.dst); 359 ip6_del_rt(aca->aca_rt); 360 361 aca_put(aca); 362 return 0; 363 } 364 365 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr) 366 { 367 int ret; 368 struct inet6_dev *idev = in6_dev_get(dev); 369 if (idev == NULL) 370 return -ENODEV; 371 ret = __ipv6_dev_ac_dec(idev, addr); 372 in6_dev_put(idev); 373 return ret; 374 } 375 376 /* 377 * check if the interface has this anycast address 378 */ 379 static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr) 380 { 381 struct inet6_dev *idev; 382 struct ifacaddr6 *aca; 383 384 idev = in6_dev_get(dev); 385 if (idev) { 386 read_lock_bh(&idev->lock); 387 for (aca = idev->ac_list; aca; aca = aca->aca_next) 388 if (ipv6_addr_equal(&aca->aca_addr, addr)) 389 break; 390 read_unlock_bh(&idev->lock); 391 in6_dev_put(idev); 392 return aca != NULL; 393 } 394 return 0; 395 } 396 397 /* 398 * check if given interface (or any, if dev==0) has this anycast address 399 */ 400 int ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 401 struct in6_addr *addr) 402 { 403 int found = 0; 404 405 if (dev) 406 return ipv6_chk_acast_dev(dev, addr); 407 read_lock(&dev_base_lock); 408 for_each_netdev(net, dev) 409 if (ipv6_chk_acast_dev(dev, addr)) { 410 found = 1; 411 break; 412 } 413 read_unlock(&dev_base_lock); 414 return found; 415 } 416 417 418 #ifdef CONFIG_PROC_FS 419 struct ac6_iter_state { 420 struct seq_net_private p; 421 struct net_device *dev; 422 struct inet6_dev *idev; 423 }; 424 425 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 426 427 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 428 { 429 struct ifacaddr6 *im = NULL; 430 struct ac6_iter_state *state = ac6_seq_private(seq); 431 struct net *net = seq_file_net(seq); 432 433 state->idev = NULL; 434 for_each_netdev(net, state->dev) { 435 struct inet6_dev *idev; 436 idev = in6_dev_get(state->dev); 437 if (!idev) 438 continue; 439 read_lock_bh(&idev->lock); 440 im = idev->ac_list; 441 if (im) { 442 state->idev = idev; 443 break; 444 } 445 read_unlock_bh(&idev->lock); 446 in6_dev_put(idev); 447 } 448 return im; 449 } 450 451 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 452 { 453 struct ac6_iter_state *state = ac6_seq_private(seq); 454 455 im = im->aca_next; 456 while (!im) { 457 if (likely(state->idev != NULL)) { 458 read_unlock_bh(&state->idev->lock); 459 in6_dev_put(state->idev); 460 } 461 state->dev = next_net_device(state->dev); 462 if (!state->dev) { 463 state->idev = NULL; 464 break; 465 } 466 state->idev = in6_dev_get(state->dev); 467 if (!state->idev) 468 continue; 469 read_lock_bh(&state->idev->lock); 470 im = state->idev->ac_list; 471 } 472 return im; 473 } 474 475 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 476 { 477 struct ifacaddr6 *im = ac6_get_first(seq); 478 if (im) 479 while (pos && (im = ac6_get_next(seq, im)) != NULL) 480 --pos; 481 return pos ? NULL : im; 482 } 483 484 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 485 __acquires(dev_base_lock) 486 { 487 read_lock(&dev_base_lock); 488 return ac6_get_idx(seq, *pos); 489 } 490 491 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 492 { 493 struct ifacaddr6 *im; 494 im = ac6_get_next(seq, v); 495 ++*pos; 496 return im; 497 } 498 499 static void ac6_seq_stop(struct seq_file *seq, void *v) 500 __releases(dev_base_lock) 501 { 502 struct ac6_iter_state *state = ac6_seq_private(seq); 503 if (likely(state->idev != NULL)) { 504 read_unlock_bh(&state->idev->lock); 505 in6_dev_put(state->idev); 506 } 507 read_unlock(&dev_base_lock); 508 } 509 510 static int ac6_seq_show(struct seq_file *seq, void *v) 511 { 512 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 513 struct ac6_iter_state *state = ac6_seq_private(seq); 514 515 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 516 state->dev->ifindex, state->dev->name, 517 &im->aca_addr, im->aca_users); 518 return 0; 519 } 520 521 static const struct seq_operations ac6_seq_ops = { 522 .start = ac6_seq_start, 523 .next = ac6_seq_next, 524 .stop = ac6_seq_stop, 525 .show = ac6_seq_show, 526 }; 527 528 static int ac6_seq_open(struct inode *inode, struct file *file) 529 { 530 return seq_open_net(inode, file, &ac6_seq_ops, 531 sizeof(struct ac6_iter_state)); 532 } 533 534 static const struct file_operations ac6_seq_fops = { 535 .owner = THIS_MODULE, 536 .open = ac6_seq_open, 537 .read = seq_read, 538 .llseek = seq_lseek, 539 .release = seq_release_net, 540 }; 541 542 int ac6_proc_init(struct net *net) 543 { 544 if (!proc_net_fops_create(net, "anycast6", S_IRUGO, &ac6_seq_fops)) 545 return -ENOMEM; 546 547 return 0; 548 } 549 550 void ac6_proc_exit(struct net *net) 551 { 552 proc_net_remove(net, "anycast6"); 553 } 554 #endif 555 556