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_SPINLOCK(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 (!ns_capable(net->user_ns, 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 rtnl_lock(); 81 rcu_read_lock(); 82 if (ifindex == 0) { 83 struct rt6_info *rt; 84 85 rt = rt6_lookup(net, addr, NULL, 0, 0); 86 if (rt) { 87 dev = rt->dst.dev; 88 ip6_rt_put(rt); 89 } else if (ishost) { 90 err = -EADDRNOTAVAIL; 91 goto error; 92 } else { 93 /* router, no matching interface: just pick one */ 94 dev = dev_get_by_flags_rcu(net, IFF_UP, 95 IFF_UP | IFF_LOOPBACK); 96 } 97 } else 98 dev = dev_get_by_index_rcu(net, ifindex); 99 100 if (dev == NULL) { 101 err = -ENODEV; 102 goto error; 103 } 104 105 idev = __in6_dev_get(dev); 106 if (!idev) { 107 if (ifindex) 108 err = -ENODEV; 109 else 110 err = -EADDRNOTAVAIL; 111 goto error; 112 } 113 /* reset ishost, now that we have a specific device */ 114 ishost = !idev->cnf.forwarding; 115 116 pac->acl_ifindex = dev->ifindex; 117 118 /* XXX 119 * For hosts, allow link-local or matching prefix anycasts. 120 * This obviates the need for propagating anycast routes while 121 * still allowing some non-router anycast participation. 122 */ 123 if (!ipv6_chk_prefix(addr, dev)) { 124 if (ishost) 125 err = -EADDRNOTAVAIL; 126 if (err) 127 goto error; 128 } 129 130 err = ipv6_dev_ac_inc(dev, addr); 131 if (!err) { 132 spin_lock_bh(&ipv6_sk_ac_lock); 133 pac->acl_next = np->ipv6_ac_list; 134 np->ipv6_ac_list = pac; 135 spin_unlock_bh(&ipv6_sk_ac_lock); 136 pac = NULL; 137 } 138 139 error: 140 rcu_read_unlock(); 141 rtnl_unlock(); 142 if (pac) 143 sock_kfree_s(sk, pac, sizeof(*pac)); 144 return err; 145 } 146 147 /* 148 * socket leave an anycast group 149 */ 150 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 151 { 152 struct ipv6_pinfo *np = inet6_sk(sk); 153 struct net_device *dev; 154 struct ipv6_ac_socklist *pac, *prev_pac; 155 struct net *net = sock_net(sk); 156 157 spin_lock_bh(&ipv6_sk_ac_lock); 158 prev_pac = NULL; 159 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 160 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 161 ipv6_addr_equal(&pac->acl_addr, addr)) 162 break; 163 prev_pac = pac; 164 } 165 if (!pac) { 166 spin_unlock_bh(&ipv6_sk_ac_lock); 167 return -ENOENT; 168 } 169 if (prev_pac) 170 prev_pac->acl_next = pac->acl_next; 171 else 172 np->ipv6_ac_list = pac->acl_next; 173 174 spin_unlock_bh(&ipv6_sk_ac_lock); 175 176 rtnl_lock(); 177 rcu_read_lock(); 178 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 179 if (dev) 180 ipv6_dev_ac_dec(dev, &pac->acl_addr); 181 rcu_read_unlock(); 182 rtnl_unlock(); 183 184 sock_kfree_s(sk, pac, sizeof(*pac)); 185 return 0; 186 } 187 188 void ipv6_sock_ac_close(struct sock *sk) 189 { 190 struct ipv6_pinfo *np = inet6_sk(sk); 191 struct net_device *dev = NULL; 192 struct ipv6_ac_socklist *pac; 193 struct net *net = sock_net(sk); 194 int prev_index; 195 196 if (!np->ipv6_ac_list) 197 return; 198 199 spin_lock_bh(&ipv6_sk_ac_lock); 200 pac = np->ipv6_ac_list; 201 np->ipv6_ac_list = NULL; 202 spin_unlock_bh(&ipv6_sk_ac_lock); 203 204 prev_index = 0; 205 rtnl_lock(); 206 rcu_read_lock(); 207 while (pac) { 208 struct ipv6_ac_socklist *next = pac->acl_next; 209 210 if (pac->acl_ifindex != prev_index) { 211 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 212 prev_index = pac->acl_ifindex; 213 } 214 if (dev) 215 ipv6_dev_ac_dec(dev, &pac->acl_addr); 216 sock_kfree_s(sk, pac, sizeof(*pac)); 217 pac = next; 218 } 219 rcu_read_unlock(); 220 rtnl_unlock(); 221 } 222 223 static void aca_put(struct ifacaddr6 *ac) 224 { 225 if (atomic_dec_and_test(&ac->aca_refcnt)) { 226 in6_dev_put(ac->aca_idev); 227 dst_release(&ac->aca_rt->dst); 228 kfree(ac); 229 } 230 } 231 232 /* 233 * device anycast group inc (add if not found) 234 */ 235 int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr) 236 { 237 struct ifacaddr6 *aca; 238 struct inet6_dev *idev; 239 struct rt6_info *rt; 240 int err; 241 242 ASSERT_RTNL(); 243 244 idev = in6_dev_get(dev); 245 246 if (idev == NULL) 247 return -EINVAL; 248 249 write_lock_bh(&idev->lock); 250 if (idev->dead) { 251 err = -ENODEV; 252 goto out; 253 } 254 255 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 256 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 257 aca->aca_users++; 258 err = 0; 259 goto out; 260 } 261 } 262 263 /* 264 * not found: create a new one. 265 */ 266 267 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); 268 269 if (aca == NULL) { 270 err = -ENOMEM; 271 goto out; 272 } 273 274 rt = addrconf_dst_alloc(idev, addr, true); 275 if (IS_ERR(rt)) { 276 kfree(aca); 277 err = PTR_ERR(rt); 278 goto out; 279 } 280 281 aca->aca_addr = *addr; 282 aca->aca_idev = idev; 283 aca->aca_rt = rt; 284 aca->aca_users = 1; 285 /* aca_tstamp should be updated upon changes */ 286 aca->aca_cstamp = aca->aca_tstamp = jiffies; 287 atomic_set(&aca->aca_refcnt, 2); 288 spin_lock_init(&aca->aca_lock); 289 290 aca->aca_next = idev->ac_list; 291 idev->ac_list = aca; 292 write_unlock_bh(&idev->lock); 293 294 ip6_ins_rt(rt); 295 296 addrconf_join_solict(dev, &aca->aca_addr); 297 298 aca_put(aca); 299 return 0; 300 out: 301 write_unlock_bh(&idev->lock); 302 in6_dev_put(idev); 303 return err; 304 } 305 306 /* 307 * device anycast group decrement 308 */ 309 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 310 { 311 struct ifacaddr6 *aca, *prev_aca; 312 313 ASSERT_RTNL(); 314 315 write_lock_bh(&idev->lock); 316 prev_aca = NULL; 317 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 318 if (ipv6_addr_equal(&aca->aca_addr, addr)) 319 break; 320 prev_aca = aca; 321 } 322 if (!aca) { 323 write_unlock_bh(&idev->lock); 324 return -ENOENT; 325 } 326 if (--aca->aca_users > 0) { 327 write_unlock_bh(&idev->lock); 328 return 0; 329 } 330 if (prev_aca) 331 prev_aca->aca_next = aca->aca_next; 332 else 333 idev->ac_list = aca->aca_next; 334 write_unlock_bh(&idev->lock); 335 addrconf_leave_solict(idev, &aca->aca_addr); 336 337 dst_hold(&aca->aca_rt->dst); 338 ip6_del_rt(aca->aca_rt); 339 340 aca_put(aca); 341 return 0; 342 } 343 344 /* called with rcu_read_lock() */ 345 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 346 { 347 struct inet6_dev *idev = __in6_dev_get(dev); 348 349 if (idev == NULL) 350 return -ENODEV; 351 return __ipv6_dev_ac_dec(idev, addr); 352 } 353 354 /* 355 * check if the interface has this anycast address 356 * called with rcu_read_lock() 357 */ 358 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 359 { 360 struct inet6_dev *idev; 361 struct ifacaddr6 *aca; 362 363 idev = __in6_dev_get(dev); 364 if (idev) { 365 read_lock_bh(&idev->lock); 366 for (aca = idev->ac_list; aca; aca = aca->aca_next) 367 if (ipv6_addr_equal(&aca->aca_addr, addr)) 368 break; 369 read_unlock_bh(&idev->lock); 370 return aca != NULL; 371 } 372 return false; 373 } 374 375 /* 376 * check if given interface (or any, if dev==0) has this anycast address 377 */ 378 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 379 const struct in6_addr *addr) 380 { 381 bool found = false; 382 383 rcu_read_lock(); 384 if (dev) 385 found = ipv6_chk_acast_dev(dev, addr); 386 else 387 for_each_netdev_rcu(net, dev) 388 if (ipv6_chk_acast_dev(dev, addr)) { 389 found = true; 390 break; 391 } 392 rcu_read_unlock(); 393 return found; 394 } 395 396 /* check if this anycast address is link-local on given interface or 397 * is global 398 */ 399 bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev, 400 const struct in6_addr *addr) 401 { 402 return ipv6_chk_acast_addr(net, 403 (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ? 404 dev : NULL), 405 addr); 406 } 407 408 #ifdef CONFIG_PROC_FS 409 struct ac6_iter_state { 410 struct seq_net_private p; 411 struct net_device *dev; 412 struct inet6_dev *idev; 413 }; 414 415 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 416 417 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 418 { 419 struct ifacaddr6 *im = NULL; 420 struct ac6_iter_state *state = ac6_seq_private(seq); 421 struct net *net = seq_file_net(seq); 422 423 state->idev = NULL; 424 for_each_netdev_rcu(net, state->dev) { 425 struct inet6_dev *idev; 426 idev = __in6_dev_get(state->dev); 427 if (!idev) 428 continue; 429 read_lock_bh(&idev->lock); 430 im = idev->ac_list; 431 if (im) { 432 state->idev = idev; 433 break; 434 } 435 read_unlock_bh(&idev->lock); 436 } 437 return im; 438 } 439 440 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 441 { 442 struct ac6_iter_state *state = ac6_seq_private(seq); 443 444 im = im->aca_next; 445 while (!im) { 446 if (likely(state->idev != NULL)) 447 read_unlock_bh(&state->idev->lock); 448 449 state->dev = next_net_device_rcu(state->dev); 450 if (!state->dev) { 451 state->idev = NULL; 452 break; 453 } 454 state->idev = __in6_dev_get(state->dev); 455 if (!state->idev) 456 continue; 457 read_lock_bh(&state->idev->lock); 458 im = state->idev->ac_list; 459 } 460 return im; 461 } 462 463 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 464 { 465 struct ifacaddr6 *im = ac6_get_first(seq); 466 if (im) 467 while (pos && (im = ac6_get_next(seq, im)) != NULL) 468 --pos; 469 return pos ? NULL : im; 470 } 471 472 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 473 __acquires(RCU) 474 { 475 rcu_read_lock(); 476 return ac6_get_idx(seq, *pos); 477 } 478 479 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 480 { 481 struct ifacaddr6 *im = ac6_get_next(seq, v); 482 483 ++*pos; 484 return im; 485 } 486 487 static void ac6_seq_stop(struct seq_file *seq, void *v) 488 __releases(RCU) 489 { 490 struct ac6_iter_state *state = ac6_seq_private(seq); 491 492 if (likely(state->idev != NULL)) { 493 read_unlock_bh(&state->idev->lock); 494 state->idev = NULL; 495 } 496 rcu_read_unlock(); 497 } 498 499 static int ac6_seq_show(struct seq_file *seq, void *v) 500 { 501 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 502 struct ac6_iter_state *state = ac6_seq_private(seq); 503 504 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 505 state->dev->ifindex, state->dev->name, 506 &im->aca_addr, im->aca_users); 507 return 0; 508 } 509 510 static const struct seq_operations ac6_seq_ops = { 511 .start = ac6_seq_start, 512 .next = ac6_seq_next, 513 .stop = ac6_seq_stop, 514 .show = ac6_seq_show, 515 }; 516 517 static int ac6_seq_open(struct inode *inode, struct file *file) 518 { 519 return seq_open_net(inode, file, &ac6_seq_ops, 520 sizeof(struct ac6_iter_state)); 521 } 522 523 static const struct file_operations ac6_seq_fops = { 524 .owner = THIS_MODULE, 525 .open = ac6_seq_open, 526 .read = seq_read, 527 .llseek = seq_lseek, 528 .release = seq_release_net, 529 }; 530 531 int __net_init ac6_proc_init(struct net *net) 532 { 533 if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops)) 534 return -ENOMEM; 535 536 return 0; 537 } 538 539 void ac6_proc_exit(struct net *net) 540 { 541 remove_proc_entry("anycast6", net->proc_net); 542 } 543 #endif 544 545