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 /* 50 * socket join an anycast group 51 */ 52 53 int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) 54 { 55 struct ipv6_pinfo *np = inet6_sk(sk); 56 struct net_device *dev = NULL; 57 struct inet6_dev *idev; 58 struct ipv6_ac_socklist *pac; 59 struct net *net = sock_net(sk); 60 int ishost = !net->ipv6.devconf_all->forwarding; 61 int err = 0; 62 63 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 64 return -EPERM; 65 if (ipv6_addr_is_multicast(addr)) 66 return -EINVAL; 67 if (ipv6_chk_addr(net, addr, NULL, 0)) 68 return -EINVAL; 69 70 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 71 if (pac == NULL) 72 return -ENOMEM; 73 pac->acl_next = NULL; 74 pac->acl_addr = *addr; 75 76 rtnl_lock(); 77 if (ifindex == 0) { 78 struct rt6_info *rt; 79 80 rt = rt6_lookup(net, addr, NULL, 0, 0); 81 if (rt) { 82 dev = rt->dst.dev; 83 ip6_rt_put(rt); 84 } else if (ishost) { 85 err = -EADDRNOTAVAIL; 86 goto error; 87 } else { 88 /* router, no matching interface: just pick one */ 89 dev = __dev_get_by_flags(net, IFF_UP, 90 IFF_UP | IFF_LOOPBACK); 91 } 92 } else 93 dev = __dev_get_by_index(net, ifindex); 94 95 if (dev == NULL) { 96 err = -ENODEV; 97 goto error; 98 } 99 100 idev = __in6_dev_get(dev); 101 if (!idev) { 102 if (ifindex) 103 err = -ENODEV; 104 else 105 err = -EADDRNOTAVAIL; 106 goto error; 107 } 108 /* reset ishost, now that we have a specific device */ 109 ishost = !idev->cnf.forwarding; 110 111 pac->acl_ifindex = dev->ifindex; 112 113 /* XXX 114 * For hosts, allow link-local or matching prefix anycasts. 115 * This obviates the need for propagating anycast routes while 116 * still allowing some non-router anycast participation. 117 */ 118 if (!ipv6_chk_prefix(addr, dev)) { 119 if (ishost) 120 err = -EADDRNOTAVAIL; 121 if (err) 122 goto error; 123 } 124 125 err = __ipv6_dev_ac_inc(idev, addr); 126 if (!err) { 127 pac->acl_next = np->ipv6_ac_list; 128 np->ipv6_ac_list = pac; 129 pac = NULL; 130 } 131 132 error: 133 rtnl_unlock(); 134 if (pac) 135 sock_kfree_s(sk, pac, sizeof(*pac)); 136 return err; 137 } 138 139 /* 140 * socket leave an anycast group 141 */ 142 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 143 { 144 struct ipv6_pinfo *np = inet6_sk(sk); 145 struct net_device *dev; 146 struct ipv6_ac_socklist *pac, *prev_pac; 147 struct net *net = sock_net(sk); 148 149 rtnl_lock(); 150 prev_pac = NULL; 151 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 152 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 153 ipv6_addr_equal(&pac->acl_addr, addr)) 154 break; 155 prev_pac = pac; 156 } 157 if (!pac) { 158 rtnl_unlock(); 159 return -ENOENT; 160 } 161 if (prev_pac) 162 prev_pac->acl_next = pac->acl_next; 163 else 164 np->ipv6_ac_list = pac->acl_next; 165 166 dev = __dev_get_by_index(net, pac->acl_ifindex); 167 if (dev) 168 ipv6_dev_ac_dec(dev, &pac->acl_addr); 169 rtnl_unlock(); 170 171 sock_kfree_s(sk, pac, sizeof(*pac)); 172 return 0; 173 } 174 175 void ipv6_sock_ac_close(struct sock *sk) 176 { 177 struct ipv6_pinfo *np = inet6_sk(sk); 178 struct net_device *dev = NULL; 179 struct ipv6_ac_socklist *pac; 180 struct net *net = sock_net(sk); 181 int prev_index; 182 183 if (!np->ipv6_ac_list) 184 return; 185 186 rtnl_lock(); 187 pac = np->ipv6_ac_list; 188 np->ipv6_ac_list = NULL; 189 190 prev_index = 0; 191 while (pac) { 192 struct ipv6_ac_socklist *next = pac->acl_next; 193 194 if (pac->acl_ifindex != prev_index) { 195 dev = __dev_get_by_index(net, pac->acl_ifindex); 196 prev_index = pac->acl_ifindex; 197 } 198 if (dev) 199 ipv6_dev_ac_dec(dev, &pac->acl_addr); 200 sock_kfree_s(sk, pac, sizeof(*pac)); 201 pac = next; 202 } 203 rtnl_unlock(); 204 } 205 206 static void aca_get(struct ifacaddr6 *aca) 207 { 208 atomic_inc(&aca->aca_refcnt); 209 } 210 211 static void aca_put(struct ifacaddr6 *ac) 212 { 213 if (atomic_dec_and_test(&ac->aca_refcnt)) { 214 in6_dev_put(ac->aca_idev); 215 dst_release(&ac->aca_rt->dst); 216 kfree(ac); 217 } 218 } 219 220 static struct ifacaddr6 *aca_alloc(struct rt6_info *rt, 221 const struct in6_addr *addr) 222 { 223 struct inet6_dev *idev = rt->rt6i_idev; 224 struct ifacaddr6 *aca; 225 226 aca = kzalloc(sizeof(*aca), GFP_ATOMIC); 227 if (aca == NULL) 228 return NULL; 229 230 aca->aca_addr = *addr; 231 in6_dev_hold(idev); 232 aca->aca_idev = idev; 233 aca->aca_rt = rt; 234 aca->aca_users = 1; 235 /* aca_tstamp should be updated upon changes */ 236 aca->aca_cstamp = aca->aca_tstamp = jiffies; 237 atomic_set(&aca->aca_refcnt, 1); 238 239 return aca; 240 } 241 242 /* 243 * device anycast group inc (add if not found) 244 */ 245 int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr) 246 { 247 struct ifacaddr6 *aca; 248 struct rt6_info *rt; 249 int err; 250 251 ASSERT_RTNL(); 252 253 write_lock_bh(&idev->lock); 254 if (idev->dead) { 255 err = -ENODEV; 256 goto out; 257 } 258 259 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 260 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 261 aca->aca_users++; 262 err = 0; 263 goto out; 264 } 265 } 266 267 rt = addrconf_dst_alloc(idev, addr, true); 268 if (IS_ERR(rt)) { 269 err = PTR_ERR(rt); 270 goto out; 271 } 272 aca = aca_alloc(rt, addr); 273 if (aca == NULL) { 274 ip6_rt_put(rt); 275 err = -ENOMEM; 276 goto out; 277 } 278 279 aca->aca_next = idev->ac_list; 280 idev->ac_list = aca; 281 282 /* Hold this for addrconf_join_solict() below before we unlock, 283 * it is already exposed via idev->ac_list. 284 */ 285 aca_get(aca); 286 write_unlock_bh(&idev->lock); 287 288 ip6_ins_rt(rt); 289 290 addrconf_join_solict(idev->dev, &aca->aca_addr); 291 292 aca_put(aca); 293 return 0; 294 out: 295 write_unlock_bh(&idev->lock); 296 return err; 297 } 298 299 /* 300 * device anycast group decrement 301 */ 302 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 303 { 304 struct ifacaddr6 *aca, *prev_aca; 305 306 ASSERT_RTNL(); 307 308 write_lock_bh(&idev->lock); 309 prev_aca = NULL; 310 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 311 if (ipv6_addr_equal(&aca->aca_addr, addr)) 312 break; 313 prev_aca = aca; 314 } 315 if (!aca) { 316 write_unlock_bh(&idev->lock); 317 return -ENOENT; 318 } 319 if (--aca->aca_users > 0) { 320 write_unlock_bh(&idev->lock); 321 return 0; 322 } 323 if (prev_aca) 324 prev_aca->aca_next = aca->aca_next; 325 else 326 idev->ac_list = aca->aca_next; 327 write_unlock_bh(&idev->lock); 328 addrconf_leave_solict(idev, &aca->aca_addr); 329 330 dst_hold(&aca->aca_rt->dst); 331 ip6_del_rt(aca->aca_rt); 332 333 aca_put(aca); 334 return 0; 335 } 336 337 /* called with rtnl_lock() */ 338 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 339 { 340 struct inet6_dev *idev = __in6_dev_get(dev); 341 342 if (idev == NULL) 343 return -ENODEV; 344 return __ipv6_dev_ac_dec(idev, addr); 345 } 346 347 void ipv6_ac_destroy_dev(struct inet6_dev *idev) 348 { 349 struct ifacaddr6 *aca; 350 351 write_lock_bh(&idev->lock); 352 while ((aca = idev->ac_list) != NULL) { 353 idev->ac_list = aca->aca_next; 354 write_unlock_bh(&idev->lock); 355 356 addrconf_leave_solict(idev, &aca->aca_addr); 357 358 dst_hold(&aca->aca_rt->dst); 359 ip6_del_rt(aca->aca_rt); 360 361 aca_put(aca); 362 363 write_lock_bh(&idev->lock); 364 } 365 write_unlock_bh(&idev->lock); 366 } 367 368 /* 369 * check if the interface has this anycast address 370 * called with rcu_read_lock() 371 */ 372 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 373 { 374 struct inet6_dev *idev; 375 struct ifacaddr6 *aca; 376 377 idev = __in6_dev_get(dev); 378 if (idev) { 379 read_lock_bh(&idev->lock); 380 for (aca = idev->ac_list; aca; aca = aca->aca_next) 381 if (ipv6_addr_equal(&aca->aca_addr, addr)) 382 break; 383 read_unlock_bh(&idev->lock); 384 return aca != NULL; 385 } 386 return false; 387 } 388 389 /* 390 * check if given interface (or any, if dev==0) has this anycast address 391 */ 392 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 393 const struct in6_addr *addr) 394 { 395 bool found = false; 396 397 rcu_read_lock(); 398 if (dev) 399 found = ipv6_chk_acast_dev(dev, addr); 400 else 401 for_each_netdev_rcu(net, dev) 402 if (ipv6_chk_acast_dev(dev, addr)) { 403 found = true; 404 break; 405 } 406 rcu_read_unlock(); 407 return found; 408 } 409 410 /* check if this anycast address is link-local on given interface or 411 * is global 412 */ 413 bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev, 414 const struct in6_addr *addr) 415 { 416 return ipv6_chk_acast_addr(net, 417 (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ? 418 dev : NULL), 419 addr); 420 } 421 422 #ifdef CONFIG_PROC_FS 423 struct ac6_iter_state { 424 struct seq_net_private p; 425 struct net_device *dev; 426 struct inet6_dev *idev; 427 }; 428 429 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 430 431 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 432 { 433 struct ifacaddr6 *im = NULL; 434 struct ac6_iter_state *state = ac6_seq_private(seq); 435 struct net *net = seq_file_net(seq); 436 437 state->idev = NULL; 438 for_each_netdev_rcu(net, state->dev) { 439 struct inet6_dev *idev; 440 idev = __in6_dev_get(state->dev); 441 if (!idev) 442 continue; 443 read_lock_bh(&idev->lock); 444 im = idev->ac_list; 445 if (im) { 446 state->idev = idev; 447 break; 448 } 449 read_unlock_bh(&idev->lock); 450 } 451 return im; 452 } 453 454 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 455 { 456 struct ac6_iter_state *state = ac6_seq_private(seq); 457 458 im = im->aca_next; 459 while (!im) { 460 if (likely(state->idev != NULL)) 461 read_unlock_bh(&state->idev->lock); 462 463 state->dev = next_net_device_rcu(state->dev); 464 if (!state->dev) { 465 state->idev = NULL; 466 break; 467 } 468 state->idev = __in6_dev_get(state->dev); 469 if (!state->idev) 470 continue; 471 read_lock_bh(&state->idev->lock); 472 im = state->idev->ac_list; 473 } 474 return im; 475 } 476 477 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 478 { 479 struct ifacaddr6 *im = ac6_get_first(seq); 480 if (im) 481 while (pos && (im = ac6_get_next(seq, im)) != NULL) 482 --pos; 483 return pos ? NULL : im; 484 } 485 486 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 487 __acquires(RCU) 488 { 489 rcu_read_lock(); 490 return ac6_get_idx(seq, *pos); 491 } 492 493 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 494 { 495 struct ifacaddr6 *im = ac6_get_next(seq, v); 496 497 ++*pos; 498 return im; 499 } 500 501 static void ac6_seq_stop(struct seq_file *seq, void *v) 502 __releases(RCU) 503 { 504 struct ac6_iter_state *state = ac6_seq_private(seq); 505 506 if (likely(state->idev != NULL)) { 507 read_unlock_bh(&state->idev->lock); 508 state->idev = NULL; 509 } 510 rcu_read_unlock(); 511 } 512 513 static int ac6_seq_show(struct seq_file *seq, void *v) 514 { 515 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 516 struct ac6_iter_state *state = ac6_seq_private(seq); 517 518 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 519 state->dev->ifindex, state->dev->name, 520 &im->aca_addr, im->aca_users); 521 return 0; 522 } 523 524 static const struct seq_operations ac6_seq_ops = { 525 .start = ac6_seq_start, 526 .next = ac6_seq_next, 527 .stop = ac6_seq_stop, 528 .show = ac6_seq_show, 529 }; 530 531 static int ac6_seq_open(struct inode *inode, struct file *file) 532 { 533 return seq_open_net(inode, file, &ac6_seq_ops, 534 sizeof(struct ac6_iter_state)); 535 } 536 537 static const struct file_operations ac6_seq_fops = { 538 .owner = THIS_MODULE, 539 .open = ac6_seq_open, 540 .read = seq_read, 541 .llseek = seq_lseek, 542 .release = seq_release_net, 543 }; 544 545 int __net_init ac6_proc_init(struct net *net) 546 { 547 if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops)) 548 return -ENOMEM; 549 550 return 0; 551 } 552 553 void ac6_proc_exit(struct net *net) 554 { 555 remove_proc_entry("anycast6", net->proc_net); 556 } 557 #endif 558 559