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