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 #include <linux/slab.h> 33 34 #include <net/net_namespace.h> 35 #include <net/sock.h> 36 #include <net/snmp.h> 37 38 #include <net/ipv6.h> 39 #include <net/protocol.h> 40 #include <net/if_inet6.h> 41 #include <net/ndisc.h> 42 #include <net/addrconf.h> 43 #include <net/ip6_route.h> 44 45 #include <net/checksum.h> 46 47 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr); 48 49 /* Big ac list lock for all the sockets */ 50 static DEFINE_RWLOCK(ipv6_sk_ac_lock); 51 52 53 /* 54 * socket join an anycast group 55 */ 56 57 int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) 58 { 59 struct ipv6_pinfo *np = inet6_sk(sk); 60 struct net_device *dev = NULL; 61 struct inet6_dev *idev; 62 struct ipv6_ac_socklist *pac; 63 struct net *net = sock_net(sk); 64 int ishost = !net->ipv6.devconf_all->forwarding; 65 int err = 0; 66 67 if (!capable(CAP_NET_ADMIN)) 68 return -EPERM; 69 if (ipv6_addr_is_multicast(addr)) 70 return -EINVAL; 71 if (ipv6_chk_addr(net, addr, NULL, 0)) 72 return -EINVAL; 73 74 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 75 if (pac == NULL) 76 return -ENOMEM; 77 pac->acl_next = NULL; 78 pac->acl_addr = *addr; 79 80 rcu_read_lock(); 81 if (ifindex == 0) { 82 struct rt6_info *rt; 83 84 rt = rt6_lookup(net, addr, NULL, 0, 0); 85 if (rt) { 86 dev = rt->dst.dev; 87 dst_release(&rt->dst); 88 } else if (ishost) { 89 err = -EADDRNOTAVAIL; 90 goto error; 91 } else { 92 /* router, no matching interface: just pick one */ 93 dev = dev_get_by_flags_rcu(net, IFF_UP, 94 IFF_UP | IFF_LOOPBACK); 95 } 96 } else 97 dev = dev_get_by_index_rcu(net, ifindex); 98 99 if (dev == NULL) { 100 err = -ENODEV; 101 goto error; 102 } 103 104 idev = __in6_dev_get(dev); 105 if (!idev) { 106 if (ifindex) 107 err = -ENODEV; 108 else 109 err = -EADDRNOTAVAIL; 110 goto error; 111 } 112 /* reset ishost, now that we have a specific device */ 113 ishost = !idev->cnf.forwarding; 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 error; 127 } 128 129 err = ipv6_dev_ac_inc(dev, addr); 130 if (!err) { 131 write_lock_bh(&ipv6_sk_ac_lock); 132 pac->acl_next = np->ipv6_ac_list; 133 np->ipv6_ac_list = pac; 134 write_unlock_bh(&ipv6_sk_ac_lock); 135 pac = NULL; 136 } 137 138 error: 139 rcu_read_unlock(); 140 if (pac) 141 sock_kfree_s(sk, pac, sizeof(*pac)); 142 return err; 143 } 144 145 /* 146 * socket leave an anycast group 147 */ 148 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 149 { 150 struct ipv6_pinfo *np = inet6_sk(sk); 151 struct net_device *dev; 152 struct ipv6_ac_socklist *pac, *prev_pac; 153 struct net *net = sock_net(sk); 154 155 write_lock_bh(&ipv6_sk_ac_lock); 156 prev_pac = NULL; 157 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 158 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 159 ipv6_addr_equal(&pac->acl_addr, addr)) 160 break; 161 prev_pac = pac; 162 } 163 if (!pac) { 164 write_unlock_bh(&ipv6_sk_ac_lock); 165 return -ENOENT; 166 } 167 if (prev_pac) 168 prev_pac->acl_next = pac->acl_next; 169 else 170 np->ipv6_ac_list = pac->acl_next; 171 172 write_unlock_bh(&ipv6_sk_ac_lock); 173 174 rcu_read_lock(); 175 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 176 if (dev) 177 ipv6_dev_ac_dec(dev, &pac->acl_addr); 178 rcu_read_unlock(); 179 180 sock_kfree_s(sk, pac, sizeof(*pac)); 181 return 0; 182 } 183 184 void ipv6_sock_ac_close(struct sock *sk) 185 { 186 struct ipv6_pinfo *np = inet6_sk(sk); 187 struct net_device *dev = NULL; 188 struct ipv6_ac_socklist *pac; 189 struct net *net = sock_net(sk); 190 int prev_index; 191 192 write_lock_bh(&ipv6_sk_ac_lock); 193 pac = np->ipv6_ac_list; 194 np->ipv6_ac_list = NULL; 195 write_unlock_bh(&ipv6_sk_ac_lock); 196 197 prev_index = 0; 198 rcu_read_lock(); 199 while (pac) { 200 struct ipv6_ac_socklist *next = pac->acl_next; 201 202 if (pac->acl_ifindex != prev_index) { 203 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 204 prev_index = pac->acl_ifindex; 205 } 206 if (dev) 207 ipv6_dev_ac_dec(dev, &pac->acl_addr); 208 sock_kfree_s(sk, pac, sizeof(*pac)); 209 pac = next; 210 } 211 rcu_read_unlock(); 212 } 213 214 static void aca_put(struct ifacaddr6 *ac) 215 { 216 if (atomic_dec_and_test(&ac->aca_refcnt)) { 217 in6_dev_put(ac->aca_idev); 218 dst_release(&ac->aca_rt->dst); 219 kfree(ac); 220 } 221 } 222 223 /* 224 * device anycast group inc (add if not found) 225 */ 226 int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr) 227 { 228 struct ifacaddr6 *aca; 229 struct inet6_dev *idev; 230 struct rt6_info *rt; 231 int err; 232 233 idev = in6_dev_get(dev); 234 235 if (idev == NULL) 236 return -EINVAL; 237 238 write_lock_bh(&idev->lock); 239 if (idev->dead) { 240 err = -ENODEV; 241 goto out; 242 } 243 244 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 245 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 246 aca->aca_users++; 247 err = 0; 248 goto out; 249 } 250 } 251 252 /* 253 * not found: create a new one. 254 */ 255 256 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); 257 258 if (aca == NULL) { 259 err = -ENOMEM; 260 goto out; 261 } 262 263 rt = addrconf_dst_alloc(idev, addr, true); 264 if (IS_ERR(rt)) { 265 kfree(aca); 266 err = PTR_ERR(rt); 267 goto out; 268 } 269 270 aca->aca_addr = *addr; 271 aca->aca_idev = idev; 272 aca->aca_rt = rt; 273 aca->aca_users = 1; 274 /* aca_tstamp should be updated upon changes */ 275 aca->aca_cstamp = aca->aca_tstamp = jiffies; 276 atomic_set(&aca->aca_refcnt, 2); 277 spin_lock_init(&aca->aca_lock); 278 279 aca->aca_next = idev->ac_list; 280 idev->ac_list = aca; 281 write_unlock_bh(&idev->lock); 282 283 ip6_ins_rt(rt); 284 285 addrconf_join_solict(dev, &aca->aca_addr); 286 287 aca_put(aca); 288 return 0; 289 out: 290 write_unlock_bh(&idev->lock); 291 in6_dev_put(idev); 292 return err; 293 } 294 295 /* 296 * device anycast group decrement 297 */ 298 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 299 { 300 struct ifacaddr6 *aca, *prev_aca; 301 302 write_lock_bh(&idev->lock); 303 prev_aca = NULL; 304 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 305 if (ipv6_addr_equal(&aca->aca_addr, addr)) 306 break; 307 prev_aca = aca; 308 } 309 if (!aca) { 310 write_unlock_bh(&idev->lock); 311 return -ENOENT; 312 } 313 if (--aca->aca_users > 0) { 314 write_unlock_bh(&idev->lock); 315 return 0; 316 } 317 if (prev_aca) 318 prev_aca->aca_next = aca->aca_next; 319 else 320 idev->ac_list = aca->aca_next; 321 write_unlock_bh(&idev->lock); 322 addrconf_leave_solict(idev, &aca->aca_addr); 323 324 dst_hold(&aca->aca_rt->dst); 325 ip6_del_rt(aca->aca_rt); 326 327 aca_put(aca); 328 return 0; 329 } 330 331 /* called with rcu_read_lock() */ 332 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 333 { 334 struct inet6_dev *idev = __in6_dev_get(dev); 335 336 if (idev == NULL) 337 return -ENODEV; 338 return __ipv6_dev_ac_dec(idev, addr); 339 } 340 341 /* 342 * check if the interface has this anycast address 343 * called with rcu_read_lock() 344 */ 345 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 346 { 347 struct inet6_dev *idev; 348 struct ifacaddr6 *aca; 349 350 idev = __in6_dev_get(dev); 351 if (idev) { 352 read_lock_bh(&idev->lock); 353 for (aca = idev->ac_list; aca; aca = aca->aca_next) 354 if (ipv6_addr_equal(&aca->aca_addr, addr)) 355 break; 356 read_unlock_bh(&idev->lock); 357 return aca != NULL; 358 } 359 return false; 360 } 361 362 /* 363 * check if given interface (or any, if dev==0) has this anycast address 364 */ 365 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 366 const struct in6_addr *addr) 367 { 368 bool found = false; 369 370 rcu_read_lock(); 371 if (dev) 372 found = ipv6_chk_acast_dev(dev, addr); 373 else 374 for_each_netdev_rcu(net, dev) 375 if (ipv6_chk_acast_dev(dev, addr)) { 376 found = true; 377 break; 378 } 379 rcu_read_unlock(); 380 return found; 381 } 382 383 384 #ifdef CONFIG_PROC_FS 385 struct ac6_iter_state { 386 struct seq_net_private p; 387 struct net_device *dev; 388 struct inet6_dev *idev; 389 }; 390 391 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 392 393 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 394 { 395 struct ifacaddr6 *im = NULL; 396 struct ac6_iter_state *state = ac6_seq_private(seq); 397 struct net *net = seq_file_net(seq); 398 399 state->idev = NULL; 400 for_each_netdev_rcu(net, state->dev) { 401 struct inet6_dev *idev; 402 idev = __in6_dev_get(state->dev); 403 if (!idev) 404 continue; 405 read_lock_bh(&idev->lock); 406 im = idev->ac_list; 407 if (im) { 408 state->idev = idev; 409 break; 410 } 411 read_unlock_bh(&idev->lock); 412 } 413 return im; 414 } 415 416 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 417 { 418 struct ac6_iter_state *state = ac6_seq_private(seq); 419 420 im = im->aca_next; 421 while (!im) { 422 if (likely(state->idev != NULL)) 423 read_unlock_bh(&state->idev->lock); 424 425 state->dev = next_net_device_rcu(state->dev); 426 if (!state->dev) { 427 state->idev = NULL; 428 break; 429 } 430 state->idev = __in6_dev_get(state->dev); 431 if (!state->idev) 432 continue; 433 read_lock_bh(&state->idev->lock); 434 im = state->idev->ac_list; 435 } 436 return im; 437 } 438 439 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 440 { 441 struct ifacaddr6 *im = ac6_get_first(seq); 442 if (im) 443 while (pos && (im = ac6_get_next(seq, im)) != NULL) 444 --pos; 445 return pos ? NULL : im; 446 } 447 448 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 449 __acquires(RCU) 450 { 451 rcu_read_lock(); 452 return ac6_get_idx(seq, *pos); 453 } 454 455 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 456 { 457 struct ifacaddr6 *im = ac6_get_next(seq, v); 458 459 ++*pos; 460 return im; 461 } 462 463 static void ac6_seq_stop(struct seq_file *seq, void *v) 464 __releases(RCU) 465 { 466 struct ac6_iter_state *state = ac6_seq_private(seq); 467 468 if (likely(state->idev != NULL)) { 469 read_unlock_bh(&state->idev->lock); 470 state->idev = NULL; 471 } 472 rcu_read_unlock(); 473 } 474 475 static int ac6_seq_show(struct seq_file *seq, void *v) 476 { 477 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 478 struct ac6_iter_state *state = ac6_seq_private(seq); 479 480 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 481 state->dev->ifindex, state->dev->name, 482 &im->aca_addr, im->aca_users); 483 return 0; 484 } 485 486 static const struct seq_operations ac6_seq_ops = { 487 .start = ac6_seq_start, 488 .next = ac6_seq_next, 489 .stop = ac6_seq_stop, 490 .show = ac6_seq_show, 491 }; 492 493 static int ac6_seq_open(struct inode *inode, struct file *file) 494 { 495 return seq_open_net(inode, file, &ac6_seq_ops, 496 sizeof(struct ac6_iter_state)); 497 } 498 499 static const struct file_operations ac6_seq_fops = { 500 .owner = THIS_MODULE, 501 .open = ac6_seq_open, 502 .read = seq_read, 503 .llseek = seq_lseek, 504 .release = seq_release_net, 505 }; 506 507 int __net_init ac6_proc_init(struct net *net) 508 { 509 if (!proc_net_fops_create(net, "anycast6", S_IRUGO, &ac6_seq_fops)) 510 return -ENOMEM; 511 512 return 0; 513 } 514 515 void ac6_proc_exit(struct net *net) 516 { 517 proc_net_remove(net, "anycast6"); 518 } 519 #endif 520 521