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 fib6_info_release(ac->aca_rt); 216 kfree(ac); 217 } 218 } 219 220 static struct ifacaddr6 *aca_alloc(struct fib6_info *f6i, 221 const struct in6_addr *addr) 222 { 223 struct ifacaddr6 *aca; 224 225 aca = kzalloc(sizeof(*aca), GFP_ATOMIC); 226 if (!aca) 227 return NULL; 228 229 aca->aca_addr = *addr; 230 fib6_info_hold(f6i); 231 aca->aca_rt = f6i; 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 fib6_info *f6i; 247 struct net *net; 248 int err; 249 250 ASSERT_RTNL(); 251 252 write_lock_bh(&idev->lock); 253 if (idev->dead) { 254 err = -ENODEV; 255 goto out; 256 } 257 258 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 259 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 260 aca->aca_users++; 261 err = 0; 262 goto out; 263 } 264 } 265 266 net = dev_net(idev->dev); 267 f6i = addrconf_f6i_alloc(net, idev, addr, true, GFP_ATOMIC); 268 if (IS_ERR(f6i)) { 269 err = PTR_ERR(f6i); 270 goto out; 271 } 272 aca = aca_alloc(f6i, addr); 273 if (!aca) { 274 fib6_info_release(f6i); 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(net, f6i); 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 ip6_del_rt(dev_net(idev->dev), aca->aca_rt); 331 332 aca_put(aca); 333 return 0; 334 } 335 336 /* called with rtnl_lock() */ 337 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 338 { 339 struct inet6_dev *idev = __in6_dev_get(dev); 340 341 if (!idev) 342 return -ENODEV; 343 return __ipv6_dev_ac_dec(idev, addr); 344 } 345 346 void ipv6_ac_destroy_dev(struct inet6_dev *idev) 347 { 348 struct ifacaddr6 *aca; 349 350 write_lock_bh(&idev->lock); 351 while ((aca = idev->ac_list) != NULL) { 352 idev->ac_list = aca->aca_next; 353 write_unlock_bh(&idev->lock); 354 355 addrconf_leave_solict(idev, &aca->aca_addr); 356 357 ip6_del_rt(dev_net(idev->dev), 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 int __net_init ac6_proc_init(struct net *net) 530 { 531 if (!proc_create_net("anycast6", 0444, net->proc_net, &ac6_seq_ops, 532 sizeof(struct ac6_iter_state))) 533 return -ENOMEM; 534 535 return 0; 536 } 537 538 void ac6_proc_exit(struct net *net) 539 { 540 remove_proc_entry("anycast6", net->proc_net); 541 } 542 #endif 543