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 dst_release(&ac->aca_rt->dst); 217 kfree(ac); 218 } 219 } 220 221 static struct ifacaddr6 *aca_alloc(struct rt6_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 aca->aca_rt = rt; 235 aca->aca_users = 1; 236 /* aca_tstamp should be updated upon changes */ 237 aca->aca_cstamp = aca->aca_tstamp = jiffies; 238 refcount_set(&aca->aca_refcnt, 1); 239 240 return aca; 241 } 242 243 /* 244 * device anycast group inc (add if not found) 245 */ 246 int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr) 247 { 248 struct ifacaddr6 *aca; 249 struct rt6_info *rt; 250 int err; 251 252 ASSERT_RTNL(); 253 254 write_lock_bh(&idev->lock); 255 if (idev->dead) { 256 err = -ENODEV; 257 goto out; 258 } 259 260 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 261 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 262 aca->aca_users++; 263 err = 0; 264 goto out; 265 } 266 } 267 268 rt = addrconf_dst_alloc(idev, addr, true); 269 if (IS_ERR(rt)) { 270 err = PTR_ERR(rt); 271 goto out; 272 } 273 aca = aca_alloc(rt, addr); 274 if (!aca) { 275 ip6_rt_put(rt); 276 err = -ENOMEM; 277 goto out; 278 } 279 280 aca->aca_next = idev->ac_list; 281 idev->ac_list = aca; 282 283 /* Hold this for addrconf_join_solict() below before we unlock, 284 * it is already exposed via idev->ac_list. 285 */ 286 aca_get(aca); 287 write_unlock_bh(&idev->lock); 288 289 ip6_ins_rt(rt); 290 291 addrconf_join_solict(idev->dev, &aca->aca_addr); 292 293 aca_put(aca); 294 return 0; 295 out: 296 write_unlock_bh(&idev->lock); 297 return err; 298 } 299 300 /* 301 * device anycast group decrement 302 */ 303 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 304 { 305 struct ifacaddr6 *aca, *prev_aca; 306 307 ASSERT_RTNL(); 308 309 write_lock_bh(&idev->lock); 310 prev_aca = NULL; 311 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 312 if (ipv6_addr_equal(&aca->aca_addr, addr)) 313 break; 314 prev_aca = aca; 315 } 316 if (!aca) { 317 write_unlock_bh(&idev->lock); 318 return -ENOENT; 319 } 320 if (--aca->aca_users > 0) { 321 write_unlock_bh(&idev->lock); 322 return 0; 323 } 324 if (prev_aca) 325 prev_aca->aca_next = aca->aca_next; 326 else 327 idev->ac_list = aca->aca_next; 328 write_unlock_bh(&idev->lock); 329 addrconf_leave_solict(idev, &aca->aca_addr); 330 331 dst_hold(&aca->aca_rt->dst); 332 ip6_del_rt(aca->aca_rt); 333 334 aca_put(aca); 335 return 0; 336 } 337 338 /* called with rtnl_lock() */ 339 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 340 { 341 struct inet6_dev *idev = __in6_dev_get(dev); 342 343 if (!idev) 344 return -ENODEV; 345 return __ipv6_dev_ac_dec(idev, addr); 346 } 347 348 void ipv6_ac_destroy_dev(struct inet6_dev *idev) 349 { 350 struct ifacaddr6 *aca; 351 352 write_lock_bh(&idev->lock); 353 while ((aca = idev->ac_list) != NULL) { 354 idev->ac_list = aca->aca_next; 355 write_unlock_bh(&idev->lock); 356 357 addrconf_leave_solict(idev, &aca->aca_addr); 358 359 dst_hold(&aca->aca_rt->dst); 360 ip6_del_rt(aca->aca_rt); 361 362 aca_put(aca); 363 364 write_lock_bh(&idev->lock); 365 } 366 write_unlock_bh(&idev->lock); 367 } 368 369 /* 370 * check if the interface has this anycast address 371 * called with rcu_read_lock() 372 */ 373 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 374 { 375 struct inet6_dev *idev; 376 struct ifacaddr6 *aca; 377 378 idev = __in6_dev_get(dev); 379 if (idev) { 380 read_lock_bh(&idev->lock); 381 for (aca = idev->ac_list; aca; aca = aca->aca_next) 382 if (ipv6_addr_equal(&aca->aca_addr, addr)) 383 break; 384 read_unlock_bh(&idev->lock); 385 return aca != NULL; 386 } 387 return false; 388 } 389 390 /* 391 * check if given interface (or any, if dev==0) has this anycast address 392 */ 393 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 394 const struct in6_addr *addr) 395 { 396 bool found = false; 397 398 rcu_read_lock(); 399 if (dev) 400 found = ipv6_chk_acast_dev(dev, addr); 401 else 402 for_each_netdev_rcu(net, dev) 403 if (ipv6_chk_acast_dev(dev, addr)) { 404 found = true; 405 break; 406 } 407 rcu_read_unlock(); 408 return found; 409 } 410 411 /* check if this anycast address is link-local on given interface or 412 * is global 413 */ 414 bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev, 415 const struct in6_addr *addr) 416 { 417 return ipv6_chk_acast_addr(net, 418 (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ? 419 dev : NULL), 420 addr); 421 } 422 423 #ifdef CONFIG_PROC_FS 424 struct ac6_iter_state { 425 struct seq_net_private p; 426 struct net_device *dev; 427 struct inet6_dev *idev; 428 }; 429 430 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 431 432 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 433 { 434 struct ifacaddr6 *im = NULL; 435 struct ac6_iter_state *state = ac6_seq_private(seq); 436 struct net *net = seq_file_net(seq); 437 438 state->idev = NULL; 439 for_each_netdev_rcu(net, state->dev) { 440 struct inet6_dev *idev; 441 idev = __in6_dev_get(state->dev); 442 if (!idev) 443 continue; 444 read_lock_bh(&idev->lock); 445 im = idev->ac_list; 446 if (im) { 447 state->idev = idev; 448 break; 449 } 450 read_unlock_bh(&idev->lock); 451 } 452 return im; 453 } 454 455 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 456 { 457 struct ac6_iter_state *state = ac6_seq_private(seq); 458 459 im = im->aca_next; 460 while (!im) { 461 if (likely(state->idev != NULL)) 462 read_unlock_bh(&state->idev->lock); 463 464 state->dev = next_net_device_rcu(state->dev); 465 if (!state->dev) { 466 state->idev = NULL; 467 break; 468 } 469 state->idev = __in6_dev_get(state->dev); 470 if (!state->idev) 471 continue; 472 read_lock_bh(&state->idev->lock); 473 im = state->idev->ac_list; 474 } 475 return im; 476 } 477 478 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 479 { 480 struct ifacaddr6 *im = ac6_get_first(seq); 481 if (im) 482 while (pos && (im = ac6_get_next(seq, im)) != NULL) 483 --pos; 484 return pos ? NULL : im; 485 } 486 487 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 488 __acquires(RCU) 489 { 490 rcu_read_lock(); 491 return ac6_get_idx(seq, *pos); 492 } 493 494 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 495 { 496 struct ifacaddr6 *im = ac6_get_next(seq, v); 497 498 ++*pos; 499 return im; 500 } 501 502 static void ac6_seq_stop(struct seq_file *seq, void *v) 503 __releases(RCU) 504 { 505 struct ac6_iter_state *state = ac6_seq_private(seq); 506 507 if (likely(state->idev != NULL)) { 508 read_unlock_bh(&state->idev->lock); 509 state->idev = NULL; 510 } 511 rcu_read_unlock(); 512 } 513 514 static int ac6_seq_show(struct seq_file *seq, void *v) 515 { 516 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 517 struct ac6_iter_state *state = ac6_seq_private(seq); 518 519 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 520 state->dev->ifindex, state->dev->name, 521 &im->aca_addr, im->aca_users); 522 return 0; 523 } 524 525 static const struct seq_operations ac6_seq_ops = { 526 .start = ac6_seq_start, 527 .next = ac6_seq_next, 528 .stop = ac6_seq_stop, 529 .show = ac6_seq_show, 530 }; 531 532 static int ac6_seq_open(struct inode *inode, struct file *file) 533 { 534 return seq_open_net(inode, file, &ac6_seq_ops, 535 sizeof(struct ac6_iter_state)); 536 } 537 538 static const struct file_operations ac6_seq_fops = { 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", 0444, 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