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 /* Big ac list lock for all the sockets */ 50 static DEFINE_SPINLOCK(ipv6_sk_ac_lock); 51 52 53 /* 54 * socket join an anycast group 55 */ 56 57 int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr) 58 { 59 struct ipv6_pinfo *np = inet6_sk(sk); 60 struct net_device *dev = NULL; 61 struct inet6_dev *idev; 62 struct ipv6_ac_socklist *pac; 63 struct net *net = sock_net(sk); 64 int ishost = !net->ipv6.devconf_all->forwarding; 65 int err = 0; 66 67 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 68 return -EPERM; 69 if (ipv6_addr_is_multicast(addr)) 70 return -EINVAL; 71 if (ipv6_chk_addr(net, addr, NULL, 0)) 72 return -EINVAL; 73 74 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); 75 if (pac == NULL) 76 return -ENOMEM; 77 pac->acl_next = NULL; 78 pac->acl_addr = *addr; 79 80 rcu_read_lock(); 81 if (ifindex == 0) { 82 struct rt6_info *rt; 83 84 rt = rt6_lookup(net, addr, NULL, 0, 0); 85 if (rt) { 86 dev = rt->dst.dev; 87 ip6_rt_put(rt); 88 } else if (ishost) { 89 err = -EADDRNOTAVAIL; 90 goto error; 91 } else { 92 /* router, no matching interface: just pick one */ 93 dev = dev_get_by_flags_rcu(net, IFF_UP, 94 IFF_UP | IFF_LOOPBACK); 95 } 96 } else 97 dev = dev_get_by_index_rcu(net, ifindex); 98 99 if (dev == NULL) { 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(dev, addr); 130 if (!err) { 131 spin_lock_bh(&ipv6_sk_ac_lock); 132 pac->acl_next = np->ipv6_ac_list; 133 np->ipv6_ac_list = pac; 134 spin_unlock_bh(&ipv6_sk_ac_lock); 135 pac = NULL; 136 } 137 138 error: 139 rcu_read_unlock(); 140 if (pac) 141 sock_kfree_s(sk, pac, sizeof(*pac)); 142 return err; 143 } 144 145 /* 146 * socket leave an anycast group 147 */ 148 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr) 149 { 150 struct ipv6_pinfo *np = inet6_sk(sk); 151 struct net_device *dev; 152 struct ipv6_ac_socklist *pac, *prev_pac; 153 struct net *net = sock_net(sk); 154 155 spin_lock_bh(&ipv6_sk_ac_lock); 156 prev_pac = NULL; 157 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) { 158 if ((ifindex == 0 || pac->acl_ifindex == ifindex) && 159 ipv6_addr_equal(&pac->acl_addr, addr)) 160 break; 161 prev_pac = pac; 162 } 163 if (!pac) { 164 spin_unlock_bh(&ipv6_sk_ac_lock); 165 return -ENOENT; 166 } 167 if (prev_pac) 168 prev_pac->acl_next = pac->acl_next; 169 else 170 np->ipv6_ac_list = pac->acl_next; 171 172 spin_unlock_bh(&ipv6_sk_ac_lock); 173 174 rcu_read_lock(); 175 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 176 if (dev) 177 ipv6_dev_ac_dec(dev, &pac->acl_addr); 178 rcu_read_unlock(); 179 180 sock_kfree_s(sk, pac, sizeof(*pac)); 181 return 0; 182 } 183 184 void ipv6_sock_ac_close(struct sock *sk) 185 { 186 struct ipv6_pinfo *np = inet6_sk(sk); 187 struct net_device *dev = NULL; 188 struct ipv6_ac_socklist *pac; 189 struct net *net = sock_net(sk); 190 int prev_index; 191 192 if (!np->ipv6_ac_list) 193 return; 194 195 spin_lock_bh(&ipv6_sk_ac_lock); 196 pac = np->ipv6_ac_list; 197 np->ipv6_ac_list = NULL; 198 spin_unlock_bh(&ipv6_sk_ac_lock); 199 200 prev_index = 0; 201 rcu_read_lock(); 202 while (pac) { 203 struct ipv6_ac_socklist *next = pac->acl_next; 204 205 if (pac->acl_ifindex != prev_index) { 206 dev = dev_get_by_index_rcu(net, pac->acl_ifindex); 207 prev_index = pac->acl_ifindex; 208 } 209 if (dev) 210 ipv6_dev_ac_dec(dev, &pac->acl_addr); 211 sock_kfree_s(sk, pac, sizeof(*pac)); 212 pac = next; 213 } 214 rcu_read_unlock(); 215 } 216 217 static void aca_put(struct ifacaddr6 *ac) 218 { 219 if (atomic_dec_and_test(&ac->aca_refcnt)) { 220 in6_dev_put(ac->aca_idev); 221 dst_release(&ac->aca_rt->dst); 222 kfree(ac); 223 } 224 } 225 226 /* 227 * device anycast group inc (add if not found) 228 */ 229 int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr) 230 { 231 struct ifacaddr6 *aca; 232 struct inet6_dev *idev; 233 struct rt6_info *rt; 234 int err; 235 236 idev = in6_dev_get(dev); 237 238 if (idev == NULL) 239 return -EINVAL; 240 241 write_lock_bh(&idev->lock); 242 if (idev->dead) { 243 err = -ENODEV; 244 goto out; 245 } 246 247 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 248 if (ipv6_addr_equal(&aca->aca_addr, addr)) { 249 aca->aca_users++; 250 err = 0; 251 goto out; 252 } 253 } 254 255 /* 256 * not found: create a new one. 257 */ 258 259 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); 260 261 if (aca == NULL) { 262 err = -ENOMEM; 263 goto out; 264 } 265 266 rt = addrconf_dst_alloc(idev, addr, true); 267 if (IS_ERR(rt)) { 268 kfree(aca); 269 err = PTR_ERR(rt); 270 goto out; 271 } 272 273 aca->aca_addr = *addr; 274 aca->aca_idev = idev; 275 aca->aca_rt = rt; 276 aca->aca_users = 1; 277 /* aca_tstamp should be updated upon changes */ 278 aca->aca_cstamp = aca->aca_tstamp = jiffies; 279 atomic_set(&aca->aca_refcnt, 2); 280 spin_lock_init(&aca->aca_lock); 281 282 aca->aca_next = idev->ac_list; 283 idev->ac_list = aca; 284 write_unlock_bh(&idev->lock); 285 286 ip6_ins_rt(rt); 287 288 addrconf_join_solict(dev, &aca->aca_addr); 289 290 aca_put(aca); 291 return 0; 292 out: 293 write_unlock_bh(&idev->lock); 294 in6_dev_put(idev); 295 return err; 296 } 297 298 /* 299 * device anycast group decrement 300 */ 301 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr) 302 { 303 struct ifacaddr6 *aca, *prev_aca; 304 305 write_lock_bh(&idev->lock); 306 prev_aca = NULL; 307 for (aca = idev->ac_list; aca; aca = aca->aca_next) { 308 if (ipv6_addr_equal(&aca->aca_addr, addr)) 309 break; 310 prev_aca = aca; 311 } 312 if (!aca) { 313 write_unlock_bh(&idev->lock); 314 return -ENOENT; 315 } 316 if (--aca->aca_users > 0) { 317 write_unlock_bh(&idev->lock); 318 return 0; 319 } 320 if (prev_aca) 321 prev_aca->aca_next = aca->aca_next; 322 else 323 idev->ac_list = aca->aca_next; 324 write_unlock_bh(&idev->lock); 325 addrconf_leave_solict(idev, &aca->aca_addr); 326 327 dst_hold(&aca->aca_rt->dst); 328 ip6_del_rt(aca->aca_rt); 329 330 aca_put(aca); 331 return 0; 332 } 333 334 /* called with rcu_read_lock() */ 335 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr) 336 { 337 struct inet6_dev *idev = __in6_dev_get(dev); 338 339 if (idev == NULL) 340 return -ENODEV; 341 return __ipv6_dev_ac_dec(idev, addr); 342 } 343 344 /* 345 * check if the interface has this anycast address 346 * called with rcu_read_lock() 347 */ 348 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr) 349 { 350 struct inet6_dev *idev; 351 struct ifacaddr6 *aca; 352 353 idev = __in6_dev_get(dev); 354 if (idev) { 355 read_lock_bh(&idev->lock); 356 for (aca = idev->ac_list; aca; aca = aca->aca_next) 357 if (ipv6_addr_equal(&aca->aca_addr, addr)) 358 break; 359 read_unlock_bh(&idev->lock); 360 return aca != NULL; 361 } 362 return false; 363 } 364 365 /* 366 * check if given interface (or any, if dev==0) has this anycast address 367 */ 368 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev, 369 const struct in6_addr *addr) 370 { 371 bool found = false; 372 373 rcu_read_lock(); 374 if (dev) 375 found = ipv6_chk_acast_dev(dev, addr); 376 else 377 for_each_netdev_rcu(net, dev) 378 if (ipv6_chk_acast_dev(dev, addr)) { 379 found = true; 380 break; 381 } 382 rcu_read_unlock(); 383 return found; 384 } 385 386 387 #ifdef CONFIG_PROC_FS 388 struct ac6_iter_state { 389 struct seq_net_private p; 390 struct net_device *dev; 391 struct inet6_dev *idev; 392 }; 393 394 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) 395 396 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) 397 { 398 struct ifacaddr6 *im = NULL; 399 struct ac6_iter_state *state = ac6_seq_private(seq); 400 struct net *net = seq_file_net(seq); 401 402 state->idev = NULL; 403 for_each_netdev_rcu(net, state->dev) { 404 struct inet6_dev *idev; 405 idev = __in6_dev_get(state->dev); 406 if (!idev) 407 continue; 408 read_lock_bh(&idev->lock); 409 im = idev->ac_list; 410 if (im) { 411 state->idev = idev; 412 break; 413 } 414 read_unlock_bh(&idev->lock); 415 } 416 return im; 417 } 418 419 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) 420 { 421 struct ac6_iter_state *state = ac6_seq_private(seq); 422 423 im = im->aca_next; 424 while (!im) { 425 if (likely(state->idev != NULL)) 426 read_unlock_bh(&state->idev->lock); 427 428 state->dev = next_net_device_rcu(state->dev); 429 if (!state->dev) { 430 state->idev = NULL; 431 break; 432 } 433 state->idev = __in6_dev_get(state->dev); 434 if (!state->idev) 435 continue; 436 read_lock_bh(&state->idev->lock); 437 im = state->idev->ac_list; 438 } 439 return im; 440 } 441 442 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos) 443 { 444 struct ifacaddr6 *im = ac6_get_first(seq); 445 if (im) 446 while (pos && (im = ac6_get_next(seq, im)) != NULL) 447 --pos; 448 return pos ? NULL : im; 449 } 450 451 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos) 452 __acquires(RCU) 453 { 454 rcu_read_lock(); 455 return ac6_get_idx(seq, *pos); 456 } 457 458 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos) 459 { 460 struct ifacaddr6 *im = ac6_get_next(seq, v); 461 462 ++*pos; 463 return im; 464 } 465 466 static void ac6_seq_stop(struct seq_file *seq, void *v) 467 __releases(RCU) 468 { 469 struct ac6_iter_state *state = ac6_seq_private(seq); 470 471 if (likely(state->idev != NULL)) { 472 read_unlock_bh(&state->idev->lock); 473 state->idev = NULL; 474 } 475 rcu_read_unlock(); 476 } 477 478 static int ac6_seq_show(struct seq_file *seq, void *v) 479 { 480 struct ifacaddr6 *im = (struct ifacaddr6 *)v; 481 struct ac6_iter_state *state = ac6_seq_private(seq); 482 483 seq_printf(seq, "%-4d %-15s %pi6 %5d\n", 484 state->dev->ifindex, state->dev->name, 485 &im->aca_addr, im->aca_users); 486 return 0; 487 } 488 489 static const struct seq_operations ac6_seq_ops = { 490 .start = ac6_seq_start, 491 .next = ac6_seq_next, 492 .stop = ac6_seq_stop, 493 .show = ac6_seq_show, 494 }; 495 496 static int ac6_seq_open(struct inode *inode, struct file *file) 497 { 498 return seq_open_net(inode, file, &ac6_seq_ops, 499 sizeof(struct ac6_iter_state)); 500 } 501 502 static const struct file_operations ac6_seq_fops = { 503 .owner = THIS_MODULE, 504 .open = ac6_seq_open, 505 .read = seq_read, 506 .llseek = seq_lseek, 507 .release = seq_release_net, 508 }; 509 510 int __net_init ac6_proc_init(struct net *net) 511 { 512 if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops)) 513 return -ENOMEM; 514 515 return 0; 516 } 517 518 void ac6_proc_exit(struct net *net) 519 { 520 remove_proc_entry("anycast6", net->proc_net); 521 } 522 #endif 523 524