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 70 if (ifindex) 71 dev = __dev_get_by_index(net, ifindex); 72 73 if (ipv6_chk_addr_and_flags(net, addr, dev, true, 0, IFA_F_TENTATIVE)) 74 return -EINVAL; 75 76 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 77 if (!pac) 78 return -ENOMEM; 79 pac->acl_next = NULL; 80 pac->acl_addr = *addr; 81 82 if (ifindex == 0) { 83 struct rt6_info *rt; 84 85 rt = rt6_lookup(net, addr, NULL, 0, NULL, 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(net, IFF_UP, 95 IFF_UP | IFF_LOOPBACK); 96 } 97 } 98 99 if (!dev) { 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(idev, addr); 130 if (!err) { 131 pac->acl_next = np->ipv6_ac_list; 132 np->ipv6_ac_list = pac; 133 pac = NULL; 134 } 135 136 error: 137 if (pac) 138 sock_kfree_s(sk, pac, sizeof(*pac)); 139 return err; 140 } 141 142 /* 143 * socket leave an anycast group 144 */ 145 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 146 { 147 struct ipv6_pinfo *np = inet6_sk(sk); 148 struct net_device *dev; 149 struct ipv6_ac_socklist *pac, *prev_pac; 150 struct net *net = sock_net(sk); 151 152 ASSERT_RTNL(); 153 154 prev_pac = NULL; 155 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 156 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 157 ipv6_addr_equal(&pac->acl_addr, addr)) 158 break; 159 prev_pac = pac; 160 } 161 if (!pac) 162 return -ENOENT; 163 if (prev_pac) 164 prev_pac->acl_next = pac->acl_next; 165 else 166 np->ipv6_ac_list = pac->acl_next; 167 168 dev = __dev_get_by_index(net, pac->acl_ifindex); 169 if (dev) 170 ipv6_dev_ac_dec(dev, &pac->acl_addr); 171 172 sock_kfree_s(sk, pac, sizeof(*pac)); 173 return 0; 174 } 175 176 void ipv6_sock_ac_close(struct sock *sk) 177 { 178 struct ipv6_pinfo *np = inet6_sk(sk); 179 struct net_device *dev = NULL; 180 struct ipv6_ac_socklist *pac; 181 struct net *net = sock_net(sk); 182 int prev_index; 183 184 if (!np->ipv6_ac_list) 185 return; 186 187 rtnl_lock(); 188 pac = np->ipv6_ac_list; 189 np->ipv6_ac_list = NULL; 190 191 prev_index = 0; 192 while (pac) { 193 struct ipv6_ac_socklist *next = pac->acl_next; 194 195 if (pac->acl_ifindex != prev_index) { 196 dev = __dev_get_by_index(net, pac->acl_ifindex); 197 prev_index = pac->acl_ifindex; 198 } 199 if (dev) 200 ipv6_dev_ac_dec(dev, &pac->acl_addr); 201 sock_kfree_s(sk, pac, sizeof(*pac)); 202 pac = next; 203 } 204 rtnl_unlock(); 205 } 206 207 static void aca_get(struct ifacaddr6 *aca) 208 { 209 refcount_inc(&aca->aca_refcnt); 210 } 211 212 static void aca_put(struct ifacaddr6 *ac) 213 { 214 if (refcount_dec_and_test(&ac->aca_refcnt)) { 215 in6_dev_put(ac->aca_idev); 216 fib6_info_release(ac->aca_rt); 217 kfree(ac); 218 } 219 } 220 221 static struct ifacaddr6 *aca_alloc(struct fib6_info *rt, 222 const struct in6_addr *addr) 223 { 224 struct inet6_dev *idev = rt->rt6i_idev; 225 struct ifacaddr6 *aca; 226 227 aca = kzalloc(sizeof(*aca), GFP_ATOMIC); 228 if (!aca) 229 return NULL; 230 231 aca->aca_addr = *addr; 232 in6_dev_hold(idev); 233 aca->aca_idev = idev; 234 fib6_info_hold(rt); 235 aca->aca_rt = rt; 236 aca->aca_users = 1; 237 /* aca_tstamp should be updated upon changes */ 238 aca->aca_cstamp = aca->aca_tstamp = jiffies; 239 refcount_set(&aca->aca_refcnt, 1); 240 241 return aca; 242 } 243 244 /* 245 * device anycast group inc (add if not found) 246 */ 247 int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr) 248 { 249 struct ifacaddr6 *aca; 250 struct fib6_info *rt; 251 struct net *net; 252 int err; 253 254 ASSERT_RTNL(); 255 256 write_lock_bh(&idev->lock); 257 if (idev->dead) { 258 err = -ENODEV; 259 goto out; 260 } 261 262 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 263 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 264 aca->aca_users++; 265 err = 0; 266 goto out; 267 } 268 } 269 270 net = dev_net(idev->dev); 271 rt = addrconf_dst_alloc(net, idev, addr, true, GFP_ATOMIC); 272 if (IS_ERR(rt)) { 273 err = PTR_ERR(rt); 274 goto out; 275 } 276 aca = aca_alloc(rt, addr); 277 if (!aca) { 278 fib6_info_release(rt); 279 err = -ENOMEM; 280 goto out; 281 } 282 283 aca->aca_next = idev->ac_list; 284 idev->ac_list = aca; 285 286 /* Hold this for addrconf_join_solict() below before we unlock, 287 * it is already exposed via idev->ac_list. 288 */ 289 aca_get(aca); 290 write_unlock_bh(&idev->lock); 291 292 ip6_ins_rt(net, rt); 293 294 addrconf_join_solict(idev->dev, &aca->aca_addr); 295 296 aca_put(aca); 297 return 0; 298 out: 299 write_unlock_bh(&idev->lock); 300 return err; 301 } 302 303 /* 304 * device anycast group decrement 305 */ 306 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 307 { 308 struct ifacaddr6 *aca, *prev_aca; 309 310 ASSERT_RTNL(); 311 312 write_lock_bh(&idev->lock); 313 prev_aca = NULL; 314 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 315 if (ipv6_addr_equal(&aca->aca_addr, addr)) 316 break; 317 prev_aca = aca; 318 } 319 if (!aca) { 320 write_unlock_bh(&idev->lock); 321 return -ENOENT; 322 } 323 if (--aca->aca_users > 0) { 324 write_unlock_bh(&idev->lock); 325 return 0; 326 } 327 if (prev_aca) 328 prev_aca->aca_next = aca->aca_next; 329 else 330 idev->ac_list = aca->aca_next; 331 write_unlock_bh(&idev->lock); 332 addrconf_leave_solict(idev, &aca->aca_addr); 333 334 ip6_del_rt(dev_net(idev->dev), aca->aca_rt); 335 336 aca_put(aca); 337 return 0; 338 } 339 340 /* called with rtnl_lock() */ 341 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 342 { 343 struct inet6_dev *idev = __in6_dev_get(dev); 344 345 if (!idev) 346 return -ENODEV; 347 return __ipv6_dev_ac_dec(idev, addr); 348 } 349 350 void ipv6_ac_destroy_dev(struct inet6_dev *idev) 351 { 352 struct ifacaddr6 *aca; 353 354 write_lock_bh(&idev->lock); 355 while ((aca = idev->ac_list) != NULL) { 356 idev->ac_list = aca->aca_next; 357 write_unlock_bh(&idev->lock); 358 359 addrconf_leave_solict(idev, &aca->aca_addr); 360 361 ip6_del_rt(dev_net(idev->dev), aca->aca_rt); 362 363 aca_put(aca); 364 365 write_lock_bh(&idev->lock); 366 } 367 write_unlock_bh(&idev->lock); 368 } 369 370 /* 371 * check if the interface has this anycast address 372 * called with rcu_read_lock() 373 */ 374 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 375 { 376 struct inet6_dev *idev; 377 struct ifacaddr6 *aca; 378 379 idev = __in6_dev_get(dev); 380 if (idev) { 381 read_lock_bh(&idev->lock); 382 for (aca = idev->ac_list; aca; aca = aca->aca_next) 383 if (ipv6_addr_equal(&aca->aca_addr, addr)) 384 break; 385 read_unlock_bh(&idev->lock); 386 return aca != NULL; 387 } 388 return false; 389 } 390 391 /* 392 * check if given interface (or any, if dev==0) has this anycast address 393 */ 394 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 395 const struct in6_addr *addr) 396 { 397 bool found = false; 398 399 rcu_read_lock(); 400 if (dev) 401 found = ipv6_chk_acast_dev(dev, addr); 402 else 403 for_each_netdev_rcu(net, dev) 404 if (ipv6_chk_acast_dev(dev, addr)) { 405 found = true; 406 break; 407 } 408 rcu_read_unlock(); 409 return found; 410 } 411 412 /* check if this anycast address is link-local on given interface or 413 * is global 414 */ 415 bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev, 416 const struct in6_addr *addr) 417 { 418 return ipv6_chk_acast_addr(net, 419 (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ? 420 dev : NULL), 421 addr); 422 } 423 424 #ifdef CONFIG_PROC_FS 425 struct ac6_iter_state { 426 struct seq_net_private p; 427 struct net_device *dev; 428 struct inet6_dev *idev; 429 }; 430 431 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 432 433 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 434 { 435 struct ifacaddr6 *im = NULL; 436 struct ac6_iter_state *state = ac6_seq_private(seq); 437 struct net *net = seq_file_net(seq); 438 439 state->idev = NULL; 440 for_each_netdev_rcu(net, state->dev) { 441 struct inet6_dev *idev; 442 idev = __in6_dev_get(state->dev); 443 if (!idev) 444 continue; 445 read_lock_bh(&idev->lock); 446 im = idev->ac_list; 447 if (im) { 448 state->idev = idev; 449 break; 450 } 451 read_unlock_bh(&idev->lock); 452 } 453 return im; 454 } 455 456 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 457 { 458 struct ac6_iter_state *state = ac6_seq_private(seq); 459 460 im = im->aca_next; 461 while (!im) { 462 if (likely(state->idev != NULL)) 463 read_unlock_bh(&state->idev->lock); 464 465 state->dev = next_net_device_rcu(state->dev); 466 if (!state->dev) { 467 state->idev = NULL; 468 break; 469 } 470 state->idev = __in6_dev_get(state->dev); 471 if (!state->idev) 472 continue; 473 read_lock_bh(&state->idev->lock); 474 im = state->idev->ac_list; 475 } 476 return im; 477 } 478 479 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 480 { 481 struct ifacaddr6 *im = ac6_get_first(seq); 482 if (im) 483 while (pos && (im = ac6_get_next(seq, im)) != NULL) 484 --pos; 485 return pos ? NULL : im; 486 } 487 488 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 489 __acquires(RCU) 490 { 491 rcu_read_lock(); 492 return ac6_get_idx(seq, *pos); 493 } 494 495 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 496 { 497 struct ifacaddr6 *im = ac6_get_next(seq, v); 498 499 ++*pos; 500 return im; 501 } 502 503 static void ac6_seq_stop(struct seq_file *seq, void *v) 504 __releases(RCU) 505 { 506 struct ac6_iter_state *state = ac6_seq_private(seq); 507 508 if (likely(state->idev != NULL)) { 509 read_unlock_bh(&state->idev->lock); 510 state->idev = NULL; 511 } 512 rcu_read_unlock(); 513 } 514 515 static int ac6_seq_show(struct seq_file *seq, void *v) 516 { 517 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 518 struct ac6_iter_state *state = ac6_seq_private(seq); 519 520 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 521 state->dev->ifindex, state->dev->name, 522 &im->aca_addr, im->aca_users); 523 return 0; 524 } 525 526 static const struct seq_operations ac6_seq_ops = { 527 .start = ac6_seq_start, 528 .next = ac6_seq_next, 529 .stop = ac6_seq_stop, 530 .show = ac6_seq_show, 531 }; 532 533 static int ac6_seq_open(struct inode *inode, struct file *file) 534 { 535 return seq_open_net(inode, file, &ac6_seq_ops, 536 sizeof(struct ac6_iter_state)); 537 } 538 539 static const struct file_operations ac6_seq_fops = { 540 .open = ac6_seq_open, 541 .read = seq_read, 542 .llseek = seq_lseek, 543 .release = seq_release_net, 544 }; 545 546 int __net_init ac6_proc_init(struct net *net) 547 { 548 if (!proc_create("anycast6", 0444, net->proc_net, &ac6_seq_fops)) 549 return -ENOMEM; 550 551 return 0; 552 } 553 554 void ac6_proc_exit(struct net *net) 555 { 556 remove_proc_entry("anycast6", net->proc_net); 557 } 558 #endif 559