1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * IPv4 Forwarding Information Base: FIB frontend. 7 * 8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 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/module.h> 17 #include <asm/uaccess.h> 18 #include <linux/bitops.h> 19 #include <linux/capability.h> 20 #include <linux/types.h> 21 #include <linux/kernel.h> 22 #include <linux/mm.h> 23 #include <linux/string.h> 24 #include <linux/socket.h> 25 #include <linux/sockios.h> 26 #include <linux/errno.h> 27 #include <linux/in.h> 28 #include <linux/inet.h> 29 #include <linux/inetdevice.h> 30 #include <linux/netdevice.h> 31 #include <linux/if_addr.h> 32 #include <linux/if_arp.h> 33 #include <linux/skbuff.h> 34 #include <linux/cache.h> 35 #include <linux/init.h> 36 #include <linux/list.h> 37 #include <linux/slab.h> 38 39 #include <net/ip.h> 40 #include <net/protocol.h> 41 #include <net/route.h> 42 #include <net/tcp.h> 43 #include <net/sock.h> 44 #include <net/arp.h> 45 #include <net/ip_fib.h> 46 #include <net/rtnetlink.h> 47 #include <net/xfrm.h> 48 49 #ifndef CONFIG_IP_MULTIPLE_TABLES 50 51 static int __net_init fib4_rules_init(struct net *net) 52 { 53 struct fib_table *local_table, *main_table; 54 55 main_table = fib_trie_table(RT_TABLE_MAIN, NULL); 56 if (!main_table) 57 return -ENOMEM; 58 59 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table); 60 if (!local_table) 61 goto fail; 62 63 hlist_add_head_rcu(&local_table->tb_hlist, 64 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]); 65 hlist_add_head_rcu(&main_table->tb_hlist, 66 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]); 67 return 0; 68 69 fail: 70 fib_free_table(main_table); 71 return -ENOMEM; 72 } 73 #else 74 75 struct fib_table *fib_new_table(struct net *net, u32 id) 76 { 77 struct fib_table *tb, *alias = NULL; 78 unsigned int h; 79 80 if (id == 0) 81 id = RT_TABLE_MAIN; 82 tb = fib_get_table(net, id); 83 if (tb) 84 return tb; 85 86 if (id == RT_TABLE_LOCAL) 87 alias = fib_new_table(net, RT_TABLE_MAIN); 88 89 tb = fib_trie_table(id, alias); 90 if (!tb) 91 return NULL; 92 93 switch (id) { 94 case RT_TABLE_LOCAL: 95 rcu_assign_pointer(net->ipv4.fib_local, tb); 96 break; 97 case RT_TABLE_MAIN: 98 rcu_assign_pointer(net->ipv4.fib_main, tb); 99 break; 100 case RT_TABLE_DEFAULT: 101 rcu_assign_pointer(net->ipv4.fib_default, tb); 102 break; 103 default: 104 break; 105 } 106 107 h = id & (FIB_TABLE_HASHSZ - 1); 108 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]); 109 return tb; 110 } 111 112 /* caller must hold either rtnl or rcu read lock */ 113 struct fib_table *fib_get_table(struct net *net, u32 id) 114 { 115 struct fib_table *tb; 116 struct hlist_head *head; 117 unsigned int h; 118 119 if (id == 0) 120 id = RT_TABLE_MAIN; 121 h = id & (FIB_TABLE_HASHSZ - 1); 122 123 head = &net->ipv4.fib_table_hash[h]; 124 hlist_for_each_entry_rcu(tb, head, tb_hlist) { 125 if (tb->tb_id == id) 126 return tb; 127 } 128 return NULL; 129 } 130 #endif /* CONFIG_IP_MULTIPLE_TABLES */ 131 132 static void fib_replace_table(struct net *net, struct fib_table *old, 133 struct fib_table *new) 134 { 135 #ifdef CONFIG_IP_MULTIPLE_TABLES 136 switch (new->tb_id) { 137 case RT_TABLE_LOCAL: 138 rcu_assign_pointer(net->ipv4.fib_local, new); 139 break; 140 case RT_TABLE_MAIN: 141 rcu_assign_pointer(net->ipv4.fib_main, new); 142 break; 143 case RT_TABLE_DEFAULT: 144 rcu_assign_pointer(net->ipv4.fib_default, new); 145 break; 146 default: 147 break; 148 } 149 150 #endif 151 /* replace the old table in the hlist */ 152 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist); 153 } 154 155 int fib_unmerge(struct net *net) 156 { 157 struct fib_table *old, *new; 158 159 /* attempt to fetch local table if it has been allocated */ 160 old = fib_get_table(net, RT_TABLE_LOCAL); 161 if (!old) 162 return 0; 163 164 new = fib_trie_unmerge(old); 165 if (!new) 166 return -ENOMEM; 167 168 /* replace merged table with clean table */ 169 if (new != old) { 170 fib_replace_table(net, old, new); 171 fib_free_table(old); 172 } 173 174 return 0; 175 } 176 177 static void fib_flush(struct net *net) 178 { 179 int flushed = 0; 180 unsigned int h; 181 182 for (h = 0; h < FIB_TABLE_HASHSZ; h++) { 183 struct hlist_head *head = &net->ipv4.fib_table_hash[h]; 184 struct hlist_node *tmp; 185 struct fib_table *tb; 186 187 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) 188 flushed += fib_table_flush(tb); 189 } 190 191 if (flushed) 192 rt_cache_flush(net); 193 } 194 195 void fib_flush_external(struct net *net) 196 { 197 struct fib_table *tb; 198 struct hlist_head *head; 199 unsigned int h; 200 201 for (h = 0; h < FIB_TABLE_HASHSZ; h++) { 202 head = &net->ipv4.fib_table_hash[h]; 203 hlist_for_each_entry(tb, head, tb_hlist) 204 fib_table_flush_external(tb); 205 } 206 } 207 208 /* 209 * Find address type as if only "dev" was present in the system. If 210 * on_dev is NULL then all interfaces are taken into consideration. 211 */ 212 static inline unsigned int __inet_dev_addr_type(struct net *net, 213 const struct net_device *dev, 214 __be32 addr) 215 { 216 struct flowi4 fl4 = { .daddr = addr }; 217 struct fib_result res; 218 unsigned int ret = RTN_BROADCAST; 219 struct fib_table *local_table; 220 221 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr)) 222 return RTN_BROADCAST; 223 if (ipv4_is_multicast(addr)) 224 return RTN_MULTICAST; 225 226 rcu_read_lock(); 227 228 local_table = fib_get_table(net, RT_TABLE_LOCAL); 229 if (local_table) { 230 ret = RTN_UNICAST; 231 if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) { 232 if (!dev || dev == res.fi->fib_dev) 233 ret = res.type; 234 } 235 } 236 237 rcu_read_unlock(); 238 return ret; 239 } 240 241 unsigned int inet_addr_type(struct net *net, __be32 addr) 242 { 243 return __inet_dev_addr_type(net, NULL, addr); 244 } 245 EXPORT_SYMBOL(inet_addr_type); 246 247 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 248 __be32 addr) 249 { 250 return __inet_dev_addr_type(net, dev, addr); 251 } 252 EXPORT_SYMBOL(inet_dev_addr_type); 253 254 __be32 fib_compute_spec_dst(struct sk_buff *skb) 255 { 256 struct net_device *dev = skb->dev; 257 struct in_device *in_dev; 258 struct fib_result res; 259 struct rtable *rt; 260 struct flowi4 fl4; 261 struct net *net; 262 int scope; 263 264 rt = skb_rtable(skb); 265 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) == 266 RTCF_LOCAL) 267 return ip_hdr(skb)->daddr; 268 269 in_dev = __in_dev_get_rcu(dev); 270 BUG_ON(!in_dev); 271 272 net = dev_net(dev); 273 274 scope = RT_SCOPE_UNIVERSE; 275 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) { 276 fl4.flowi4_oif = 0; 277 fl4.flowi4_iif = LOOPBACK_IFINDEX; 278 fl4.daddr = ip_hdr(skb)->saddr; 279 fl4.saddr = 0; 280 fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); 281 fl4.flowi4_scope = scope; 282 fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0; 283 fl4.flowi4_tun_key.tun_id = 0; 284 if (!fib_lookup(net, &fl4, &res, 0)) 285 return FIB_RES_PREFSRC(net, res); 286 } else { 287 scope = RT_SCOPE_LINK; 288 } 289 290 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope); 291 } 292 293 /* Given (packet source, input interface) and optional (dst, oif, tos): 294 * - (main) check, that source is valid i.e. not broadcast or our local 295 * address. 296 * - figure out what "logical" interface this packet arrived 297 * and calculate "specific destination" address. 298 * - check, that packet arrived from expected physical interface. 299 * called with rcu_read_lock() 300 */ 301 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, 302 u8 tos, int oif, struct net_device *dev, 303 int rpf, struct in_device *idev, u32 *itag) 304 { 305 int ret, no_addr; 306 struct fib_result res; 307 struct flowi4 fl4; 308 struct net *net; 309 bool dev_match; 310 311 fl4.flowi4_oif = 0; 312 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX; 313 fl4.daddr = src; 314 fl4.saddr = dst; 315 fl4.flowi4_tos = tos; 316 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 317 fl4.flowi4_tun_key.tun_id = 0; 318 319 no_addr = idev->ifa_list == NULL; 320 321 fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0; 322 323 net = dev_net(dev); 324 if (fib_lookup(net, &fl4, &res, 0)) 325 goto last_resort; 326 if (res.type != RTN_UNICAST && 327 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev))) 328 goto e_inval; 329 if (!rpf && !fib_num_tclassid_users(dev_net(dev)) && 330 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) 331 goto last_resort; 332 fib_combine_itag(itag, &res); 333 dev_match = false; 334 335 #ifdef CONFIG_IP_ROUTE_MULTIPATH 336 for (ret = 0; ret < res.fi->fib_nhs; ret++) { 337 struct fib_nh *nh = &res.fi->fib_nh[ret]; 338 339 if (nh->nh_dev == dev) { 340 dev_match = true; 341 break; 342 } 343 } 344 #else 345 if (FIB_RES_DEV(res) == dev) 346 dev_match = true; 347 #endif 348 if (dev_match) { 349 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; 350 return ret; 351 } 352 if (no_addr) 353 goto last_resort; 354 if (rpf == 1) 355 goto e_rpf; 356 fl4.flowi4_oif = dev->ifindex; 357 358 ret = 0; 359 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) { 360 if (res.type == RTN_UNICAST) 361 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; 362 } 363 return ret; 364 365 last_resort: 366 if (rpf) 367 goto e_rpf; 368 *itag = 0; 369 return 0; 370 371 e_inval: 372 return -EINVAL; 373 e_rpf: 374 return -EXDEV; 375 } 376 377 /* Ignore rp_filter for packets protected by IPsec. */ 378 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, 379 u8 tos, int oif, struct net_device *dev, 380 struct in_device *idev, u32 *itag) 381 { 382 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev); 383 384 if (!r && !fib_num_tclassid_users(dev_net(dev)) && 385 IN_DEV_ACCEPT_LOCAL(idev) && 386 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) { 387 *itag = 0; 388 return 0; 389 } 390 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag); 391 } 392 393 static inline __be32 sk_extract_addr(struct sockaddr *addr) 394 { 395 return ((struct sockaddr_in *) addr)->sin_addr.s_addr; 396 } 397 398 static int put_rtax(struct nlattr *mx, int len, int type, u32 value) 399 { 400 struct nlattr *nla; 401 402 nla = (struct nlattr *) ((char *) mx + len); 403 nla->nla_type = type; 404 nla->nla_len = nla_attr_size(4); 405 *(u32 *) nla_data(nla) = value; 406 407 return len + nla_total_size(4); 408 } 409 410 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt, 411 struct fib_config *cfg) 412 { 413 __be32 addr; 414 int plen; 415 416 memset(cfg, 0, sizeof(*cfg)); 417 cfg->fc_nlinfo.nl_net = net; 418 419 if (rt->rt_dst.sa_family != AF_INET) 420 return -EAFNOSUPPORT; 421 422 /* 423 * Check mask for validity: 424 * a) it must be contiguous. 425 * b) destination must have all host bits clear. 426 * c) if application forgot to set correct family (AF_INET), 427 * reject request unless it is absolutely clear i.e. 428 * both family and mask are zero. 429 */ 430 plen = 32; 431 addr = sk_extract_addr(&rt->rt_dst); 432 if (!(rt->rt_flags & RTF_HOST)) { 433 __be32 mask = sk_extract_addr(&rt->rt_genmask); 434 435 if (rt->rt_genmask.sa_family != AF_INET) { 436 if (mask || rt->rt_genmask.sa_family) 437 return -EAFNOSUPPORT; 438 } 439 440 if (bad_mask(mask, addr)) 441 return -EINVAL; 442 443 plen = inet_mask_len(mask); 444 } 445 446 cfg->fc_dst_len = plen; 447 cfg->fc_dst = addr; 448 449 if (cmd != SIOCDELRT) { 450 cfg->fc_nlflags = NLM_F_CREATE; 451 cfg->fc_protocol = RTPROT_BOOT; 452 } 453 454 if (rt->rt_metric) 455 cfg->fc_priority = rt->rt_metric - 1; 456 457 if (rt->rt_flags & RTF_REJECT) { 458 cfg->fc_scope = RT_SCOPE_HOST; 459 cfg->fc_type = RTN_UNREACHABLE; 460 return 0; 461 } 462 463 cfg->fc_scope = RT_SCOPE_NOWHERE; 464 cfg->fc_type = RTN_UNICAST; 465 466 if (rt->rt_dev) { 467 char *colon; 468 struct net_device *dev; 469 char devname[IFNAMSIZ]; 470 471 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1)) 472 return -EFAULT; 473 474 devname[IFNAMSIZ-1] = 0; 475 colon = strchr(devname, ':'); 476 if (colon) 477 *colon = 0; 478 dev = __dev_get_by_name(net, devname); 479 if (!dev) 480 return -ENODEV; 481 cfg->fc_oif = dev->ifindex; 482 if (colon) { 483 struct in_ifaddr *ifa; 484 struct in_device *in_dev = __in_dev_get_rtnl(dev); 485 if (!in_dev) 486 return -ENODEV; 487 *colon = ':'; 488 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) 489 if (strcmp(ifa->ifa_label, devname) == 0) 490 break; 491 if (!ifa) 492 return -ENODEV; 493 cfg->fc_prefsrc = ifa->ifa_local; 494 } 495 } 496 497 addr = sk_extract_addr(&rt->rt_gateway); 498 if (rt->rt_gateway.sa_family == AF_INET && addr) { 499 cfg->fc_gw = addr; 500 if (rt->rt_flags & RTF_GATEWAY && 501 inet_addr_type(net, addr) == RTN_UNICAST) 502 cfg->fc_scope = RT_SCOPE_UNIVERSE; 503 } 504 505 if (cmd == SIOCDELRT) 506 return 0; 507 508 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw) 509 return -EINVAL; 510 511 if (cfg->fc_scope == RT_SCOPE_NOWHERE) 512 cfg->fc_scope = RT_SCOPE_LINK; 513 514 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) { 515 struct nlattr *mx; 516 int len = 0; 517 518 mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL); 519 if (!mx) 520 return -ENOMEM; 521 522 if (rt->rt_flags & RTF_MTU) 523 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40); 524 525 if (rt->rt_flags & RTF_WINDOW) 526 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window); 527 528 if (rt->rt_flags & RTF_IRTT) 529 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3); 530 531 cfg->fc_mx = mx; 532 cfg->fc_mx_len = len; 533 } 534 535 return 0; 536 } 537 538 /* 539 * Handle IP routing ioctl calls. 540 * These are used to manipulate the routing tables 541 */ 542 int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg) 543 { 544 struct fib_config cfg; 545 struct rtentry rt; 546 int err; 547 548 switch (cmd) { 549 case SIOCADDRT: /* Add a route */ 550 case SIOCDELRT: /* Delete a route */ 551 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 552 return -EPERM; 553 554 if (copy_from_user(&rt, arg, sizeof(rt))) 555 return -EFAULT; 556 557 rtnl_lock(); 558 err = rtentry_to_fib_config(net, cmd, &rt, &cfg); 559 if (err == 0) { 560 struct fib_table *tb; 561 562 if (cmd == SIOCDELRT) { 563 tb = fib_get_table(net, cfg.fc_table); 564 if (tb) 565 err = fib_table_delete(tb, &cfg); 566 else 567 err = -ESRCH; 568 } else { 569 tb = fib_new_table(net, cfg.fc_table); 570 if (tb) 571 err = fib_table_insert(tb, &cfg); 572 else 573 err = -ENOBUFS; 574 } 575 576 /* allocated by rtentry_to_fib_config() */ 577 kfree(cfg.fc_mx); 578 } 579 rtnl_unlock(); 580 return err; 581 } 582 return -EINVAL; 583 } 584 585 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = { 586 [RTA_DST] = { .type = NLA_U32 }, 587 [RTA_SRC] = { .type = NLA_U32 }, 588 [RTA_IIF] = { .type = NLA_U32 }, 589 [RTA_OIF] = { .type = NLA_U32 }, 590 [RTA_GATEWAY] = { .type = NLA_U32 }, 591 [RTA_PRIORITY] = { .type = NLA_U32 }, 592 [RTA_PREFSRC] = { .type = NLA_U32 }, 593 [RTA_METRICS] = { .type = NLA_NESTED }, 594 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) }, 595 [RTA_FLOW] = { .type = NLA_U32 }, 596 [RTA_ENCAP_TYPE] = { .type = NLA_U16 }, 597 [RTA_ENCAP] = { .type = NLA_NESTED }, 598 }; 599 600 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, 601 struct nlmsghdr *nlh, struct fib_config *cfg) 602 { 603 struct nlattr *attr; 604 int err, remaining; 605 struct rtmsg *rtm; 606 607 err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy); 608 if (err < 0) 609 goto errout; 610 611 memset(cfg, 0, sizeof(*cfg)); 612 613 rtm = nlmsg_data(nlh); 614 cfg->fc_dst_len = rtm->rtm_dst_len; 615 cfg->fc_tos = rtm->rtm_tos; 616 cfg->fc_table = rtm->rtm_table; 617 cfg->fc_protocol = rtm->rtm_protocol; 618 cfg->fc_scope = rtm->rtm_scope; 619 cfg->fc_type = rtm->rtm_type; 620 cfg->fc_flags = rtm->rtm_flags; 621 cfg->fc_nlflags = nlh->nlmsg_flags; 622 623 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid; 624 cfg->fc_nlinfo.nlh = nlh; 625 cfg->fc_nlinfo.nl_net = net; 626 627 if (cfg->fc_type > RTN_MAX) { 628 err = -EINVAL; 629 goto errout; 630 } 631 632 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) { 633 switch (nla_type(attr)) { 634 case RTA_DST: 635 cfg->fc_dst = nla_get_be32(attr); 636 break; 637 case RTA_OIF: 638 cfg->fc_oif = nla_get_u32(attr); 639 break; 640 case RTA_GATEWAY: 641 cfg->fc_gw = nla_get_be32(attr); 642 break; 643 case RTA_PRIORITY: 644 cfg->fc_priority = nla_get_u32(attr); 645 break; 646 case RTA_PREFSRC: 647 cfg->fc_prefsrc = nla_get_be32(attr); 648 break; 649 case RTA_METRICS: 650 cfg->fc_mx = nla_data(attr); 651 cfg->fc_mx_len = nla_len(attr); 652 break; 653 case RTA_MULTIPATH: 654 cfg->fc_mp = nla_data(attr); 655 cfg->fc_mp_len = nla_len(attr); 656 break; 657 case RTA_FLOW: 658 cfg->fc_flow = nla_get_u32(attr); 659 break; 660 case RTA_TABLE: 661 cfg->fc_table = nla_get_u32(attr); 662 break; 663 case RTA_ENCAP: 664 cfg->fc_encap = attr; 665 break; 666 case RTA_ENCAP_TYPE: 667 cfg->fc_encap_type = nla_get_u16(attr); 668 break; 669 } 670 } 671 672 return 0; 673 errout: 674 return err; 675 } 676 677 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh) 678 { 679 struct net *net = sock_net(skb->sk); 680 struct fib_config cfg; 681 struct fib_table *tb; 682 int err; 683 684 err = rtm_to_fib_config(net, skb, nlh, &cfg); 685 if (err < 0) 686 goto errout; 687 688 tb = fib_get_table(net, cfg.fc_table); 689 if (!tb) { 690 err = -ESRCH; 691 goto errout; 692 } 693 694 err = fib_table_delete(tb, &cfg); 695 errout: 696 return err; 697 } 698 699 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh) 700 { 701 struct net *net = sock_net(skb->sk); 702 struct fib_config cfg; 703 struct fib_table *tb; 704 int err; 705 706 err = rtm_to_fib_config(net, skb, nlh, &cfg); 707 if (err < 0) 708 goto errout; 709 710 tb = fib_new_table(net, cfg.fc_table); 711 if (!tb) { 712 err = -ENOBUFS; 713 goto errout; 714 } 715 716 err = fib_table_insert(tb, &cfg); 717 errout: 718 return err; 719 } 720 721 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) 722 { 723 struct net *net = sock_net(skb->sk); 724 unsigned int h, s_h; 725 unsigned int e = 0, s_e; 726 struct fib_table *tb; 727 struct hlist_head *head; 728 int dumped = 0; 729 730 if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) && 731 ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED) 732 return skb->len; 733 734 s_h = cb->args[0]; 735 s_e = cb->args[1]; 736 737 rcu_read_lock(); 738 739 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) { 740 e = 0; 741 head = &net->ipv4.fib_table_hash[h]; 742 hlist_for_each_entry_rcu(tb, head, tb_hlist) { 743 if (e < s_e) 744 goto next; 745 if (dumped) 746 memset(&cb->args[2], 0, sizeof(cb->args) - 747 2 * sizeof(cb->args[0])); 748 if (fib_table_dump(tb, skb, cb) < 0) 749 goto out; 750 dumped = 1; 751 next: 752 e++; 753 } 754 } 755 out: 756 rcu_read_unlock(); 757 758 cb->args[1] = e; 759 cb->args[0] = h; 760 761 return skb->len; 762 } 763 764 /* Prepare and feed intra-kernel routing request. 765 * Really, it should be netlink message, but :-( netlink 766 * can be not configured, so that we feed it directly 767 * to fib engine. It is legal, because all events occur 768 * only when netlink is already locked. 769 */ 770 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa) 771 { 772 struct net *net = dev_net(ifa->ifa_dev->dev); 773 struct fib_table *tb; 774 struct fib_config cfg = { 775 .fc_protocol = RTPROT_KERNEL, 776 .fc_type = type, 777 .fc_dst = dst, 778 .fc_dst_len = dst_len, 779 .fc_prefsrc = ifa->ifa_local, 780 .fc_oif = ifa->ifa_dev->dev->ifindex, 781 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND, 782 .fc_nlinfo = { 783 .nl_net = net, 784 }, 785 }; 786 787 if (type == RTN_UNICAST) 788 tb = fib_new_table(net, RT_TABLE_MAIN); 789 else 790 tb = fib_new_table(net, RT_TABLE_LOCAL); 791 792 if (!tb) 793 return; 794 795 cfg.fc_table = tb->tb_id; 796 797 if (type != RTN_LOCAL) 798 cfg.fc_scope = RT_SCOPE_LINK; 799 else 800 cfg.fc_scope = RT_SCOPE_HOST; 801 802 if (cmd == RTM_NEWROUTE) 803 fib_table_insert(tb, &cfg); 804 else 805 fib_table_delete(tb, &cfg); 806 } 807 808 void fib_add_ifaddr(struct in_ifaddr *ifa) 809 { 810 struct in_device *in_dev = ifa->ifa_dev; 811 struct net_device *dev = in_dev->dev; 812 struct in_ifaddr *prim = ifa; 813 __be32 mask = ifa->ifa_mask; 814 __be32 addr = ifa->ifa_local; 815 __be32 prefix = ifa->ifa_address & mask; 816 817 if (ifa->ifa_flags & IFA_F_SECONDARY) { 818 prim = inet_ifa_byprefix(in_dev, prefix, mask); 819 if (!prim) { 820 pr_warn("%s: bug: prim == NULL\n", __func__); 821 return; 822 } 823 } 824 825 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim); 826 827 if (!(dev->flags & IFF_UP)) 828 return; 829 830 /* Add broadcast address, if it is explicitly assigned. */ 831 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) 832 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); 833 834 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) && 835 (prefix != addr || ifa->ifa_prefixlen < 32)) { 836 fib_magic(RTM_NEWROUTE, 837 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, 838 prefix, ifa->ifa_prefixlen, prim); 839 840 /* Add network specific broadcasts, when it takes a sense */ 841 if (ifa->ifa_prefixlen < 31) { 842 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim); 843 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask, 844 32, prim); 845 } 846 } 847 } 848 849 /* Delete primary or secondary address. 850 * Optionally, on secondary address promotion consider the addresses 851 * from subnet iprim as deleted, even if they are in device list. 852 * In this case the secondary ifa can be in device list. 853 */ 854 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) 855 { 856 struct in_device *in_dev = ifa->ifa_dev; 857 struct net_device *dev = in_dev->dev; 858 struct in_ifaddr *ifa1; 859 struct in_ifaddr *prim = ifa, *prim1 = NULL; 860 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask; 861 __be32 any = ifa->ifa_address & ifa->ifa_mask; 862 #define LOCAL_OK 1 863 #define BRD_OK 2 864 #define BRD0_OK 4 865 #define BRD1_OK 8 866 unsigned int ok = 0; 867 int subnet = 0; /* Primary network */ 868 int gone = 1; /* Address is missing */ 869 int same_prefsrc = 0; /* Another primary with same IP */ 870 871 if (ifa->ifa_flags & IFA_F_SECONDARY) { 872 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask); 873 if (!prim) { 874 pr_warn("%s: bug: prim == NULL\n", __func__); 875 return; 876 } 877 if (iprim && iprim != prim) { 878 pr_warn("%s: bug: iprim != prim\n", __func__); 879 return; 880 } 881 } else if (!ipv4_is_zeronet(any) && 882 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) { 883 fib_magic(RTM_DELROUTE, 884 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, 885 any, ifa->ifa_prefixlen, prim); 886 subnet = 1; 887 } 888 889 /* Deletion is more complicated than add. 890 * We should take care of not to delete too much :-) 891 * 892 * Scan address list to be sure that addresses are really gone. 893 */ 894 895 for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) { 896 if (ifa1 == ifa) { 897 /* promotion, keep the IP */ 898 gone = 0; 899 continue; 900 } 901 /* Ignore IFAs from our subnet */ 902 if (iprim && ifa1->ifa_mask == iprim->ifa_mask && 903 inet_ifa_match(ifa1->ifa_address, iprim)) 904 continue; 905 906 /* Ignore ifa1 if it uses different primary IP (prefsrc) */ 907 if (ifa1->ifa_flags & IFA_F_SECONDARY) { 908 /* Another address from our subnet? */ 909 if (ifa1->ifa_mask == prim->ifa_mask && 910 inet_ifa_match(ifa1->ifa_address, prim)) 911 prim1 = prim; 912 else { 913 /* We reached the secondaries, so 914 * same_prefsrc should be determined. 915 */ 916 if (!same_prefsrc) 917 continue; 918 /* Search new prim1 if ifa1 is not 919 * using the current prim1 920 */ 921 if (!prim1 || 922 ifa1->ifa_mask != prim1->ifa_mask || 923 !inet_ifa_match(ifa1->ifa_address, prim1)) 924 prim1 = inet_ifa_byprefix(in_dev, 925 ifa1->ifa_address, 926 ifa1->ifa_mask); 927 if (!prim1) 928 continue; 929 if (prim1->ifa_local != prim->ifa_local) 930 continue; 931 } 932 } else { 933 if (prim->ifa_local != ifa1->ifa_local) 934 continue; 935 prim1 = ifa1; 936 if (prim != prim1) 937 same_prefsrc = 1; 938 } 939 if (ifa->ifa_local == ifa1->ifa_local) 940 ok |= LOCAL_OK; 941 if (ifa->ifa_broadcast == ifa1->ifa_broadcast) 942 ok |= BRD_OK; 943 if (brd == ifa1->ifa_broadcast) 944 ok |= BRD1_OK; 945 if (any == ifa1->ifa_broadcast) 946 ok |= BRD0_OK; 947 /* primary has network specific broadcasts */ 948 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) { 949 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask; 950 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask; 951 952 if (!ipv4_is_zeronet(any1)) { 953 if (ifa->ifa_broadcast == brd1 || 954 ifa->ifa_broadcast == any1) 955 ok |= BRD_OK; 956 if (brd == brd1 || brd == any1) 957 ok |= BRD1_OK; 958 if (any == brd1 || any == any1) 959 ok |= BRD0_OK; 960 } 961 } 962 } 963 964 if (!(ok & BRD_OK)) 965 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); 966 if (subnet && ifa->ifa_prefixlen < 31) { 967 if (!(ok & BRD1_OK)) 968 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim); 969 if (!(ok & BRD0_OK)) 970 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim); 971 } 972 if (!(ok & LOCAL_OK)) { 973 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim); 974 975 /* Check, that this local address finally disappeared. */ 976 if (gone && 977 inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) { 978 /* And the last, but not the least thing. 979 * We must flush stray FIB entries. 980 * 981 * First of all, we scan fib_info list searching 982 * for stray nexthop entries, then ignite fib_flush. 983 */ 984 if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local)) 985 fib_flush(dev_net(dev)); 986 } 987 } 988 #undef LOCAL_OK 989 #undef BRD_OK 990 #undef BRD0_OK 991 #undef BRD1_OK 992 } 993 994 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn) 995 { 996 997 struct fib_result res; 998 struct flowi4 fl4 = { 999 .flowi4_mark = frn->fl_mark, 1000 .daddr = frn->fl_addr, 1001 .flowi4_tos = frn->fl_tos, 1002 .flowi4_scope = frn->fl_scope, 1003 }; 1004 struct fib_table *tb; 1005 1006 rcu_read_lock(); 1007 1008 tb = fib_get_table(net, frn->tb_id_in); 1009 1010 frn->err = -ENOENT; 1011 if (tb) { 1012 local_bh_disable(); 1013 1014 frn->tb_id = tb->tb_id; 1015 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF); 1016 1017 if (!frn->err) { 1018 frn->prefixlen = res.prefixlen; 1019 frn->nh_sel = res.nh_sel; 1020 frn->type = res.type; 1021 frn->scope = res.scope; 1022 } 1023 local_bh_enable(); 1024 } 1025 1026 rcu_read_unlock(); 1027 } 1028 1029 static void nl_fib_input(struct sk_buff *skb) 1030 { 1031 struct net *net; 1032 struct fib_result_nl *frn; 1033 struct nlmsghdr *nlh; 1034 u32 portid; 1035 1036 net = sock_net(skb->sk); 1037 nlh = nlmsg_hdr(skb); 1038 if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len || 1039 nlmsg_len(nlh) < sizeof(*frn)) 1040 return; 1041 1042 skb = netlink_skb_clone(skb, GFP_KERNEL); 1043 if (!skb) 1044 return; 1045 nlh = nlmsg_hdr(skb); 1046 1047 frn = (struct fib_result_nl *) nlmsg_data(nlh); 1048 nl_fib_lookup(net, frn); 1049 1050 portid = NETLINK_CB(skb).portid; /* netlink portid */ 1051 NETLINK_CB(skb).portid = 0; /* from kernel */ 1052 NETLINK_CB(skb).dst_group = 0; /* unicast */ 1053 netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT); 1054 } 1055 1056 static int __net_init nl_fib_lookup_init(struct net *net) 1057 { 1058 struct sock *sk; 1059 struct netlink_kernel_cfg cfg = { 1060 .input = nl_fib_input, 1061 }; 1062 1063 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg); 1064 if (!sk) 1065 return -EAFNOSUPPORT; 1066 net->ipv4.fibnl = sk; 1067 return 0; 1068 } 1069 1070 static void nl_fib_lookup_exit(struct net *net) 1071 { 1072 netlink_kernel_release(net->ipv4.fibnl); 1073 net->ipv4.fibnl = NULL; 1074 } 1075 1076 static void fib_disable_ip(struct net_device *dev, unsigned long event) 1077 { 1078 if (fib_sync_down_dev(dev, event)) 1079 fib_flush(dev_net(dev)); 1080 rt_cache_flush(dev_net(dev)); 1081 arp_ifdown(dev); 1082 } 1083 1084 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr) 1085 { 1086 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr; 1087 struct net_device *dev = ifa->ifa_dev->dev; 1088 struct net *net = dev_net(dev); 1089 1090 switch (event) { 1091 case NETDEV_UP: 1092 fib_add_ifaddr(ifa); 1093 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1094 fib_sync_up(dev, RTNH_F_DEAD); 1095 #endif 1096 atomic_inc(&net->ipv4.dev_addr_genid); 1097 rt_cache_flush(dev_net(dev)); 1098 break; 1099 case NETDEV_DOWN: 1100 fib_del_ifaddr(ifa, NULL); 1101 atomic_inc(&net->ipv4.dev_addr_genid); 1102 if (!ifa->ifa_dev->ifa_list) { 1103 /* Last address was deleted from this interface. 1104 * Disable IP. 1105 */ 1106 fib_disable_ip(dev, event); 1107 } else { 1108 rt_cache_flush(dev_net(dev)); 1109 } 1110 break; 1111 } 1112 return NOTIFY_DONE; 1113 } 1114 1115 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1116 { 1117 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1118 struct in_device *in_dev; 1119 struct net *net = dev_net(dev); 1120 unsigned int flags; 1121 1122 if (event == NETDEV_UNREGISTER) { 1123 fib_disable_ip(dev, event); 1124 rt_flush_dev(dev); 1125 return NOTIFY_DONE; 1126 } 1127 1128 in_dev = __in_dev_get_rtnl(dev); 1129 if (!in_dev) 1130 return NOTIFY_DONE; 1131 1132 switch (event) { 1133 case NETDEV_UP: 1134 for_ifa(in_dev) { 1135 fib_add_ifaddr(ifa); 1136 } endfor_ifa(in_dev); 1137 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1138 fib_sync_up(dev, RTNH_F_DEAD); 1139 #endif 1140 atomic_inc(&net->ipv4.dev_addr_genid); 1141 rt_cache_flush(net); 1142 break; 1143 case NETDEV_DOWN: 1144 fib_disable_ip(dev, event); 1145 break; 1146 case NETDEV_CHANGE: 1147 flags = dev_get_flags(dev); 1148 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1149 fib_sync_up(dev, RTNH_F_LINKDOWN); 1150 else 1151 fib_sync_down_dev(dev, event); 1152 /* fall through */ 1153 case NETDEV_CHANGEMTU: 1154 rt_cache_flush(net); 1155 break; 1156 } 1157 return NOTIFY_DONE; 1158 } 1159 1160 static struct notifier_block fib_inetaddr_notifier = { 1161 .notifier_call = fib_inetaddr_event, 1162 }; 1163 1164 static struct notifier_block fib_netdev_notifier = { 1165 .notifier_call = fib_netdev_event, 1166 }; 1167 1168 static int __net_init ip_fib_net_init(struct net *net) 1169 { 1170 int err; 1171 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ; 1172 1173 /* Avoid false sharing : Use at least a full cache line */ 1174 size = max_t(size_t, size, L1_CACHE_BYTES); 1175 1176 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL); 1177 if (!net->ipv4.fib_table_hash) 1178 return -ENOMEM; 1179 1180 err = fib4_rules_init(net); 1181 if (err < 0) 1182 goto fail; 1183 return 0; 1184 1185 fail: 1186 kfree(net->ipv4.fib_table_hash); 1187 return err; 1188 } 1189 1190 static void ip_fib_net_exit(struct net *net) 1191 { 1192 unsigned int i; 1193 1194 rtnl_lock(); 1195 #ifdef CONFIG_IP_MULTIPLE_TABLES 1196 RCU_INIT_POINTER(net->ipv4.fib_local, NULL); 1197 RCU_INIT_POINTER(net->ipv4.fib_main, NULL); 1198 RCU_INIT_POINTER(net->ipv4.fib_default, NULL); 1199 #endif 1200 for (i = 0; i < FIB_TABLE_HASHSZ; i++) { 1201 struct hlist_head *head = &net->ipv4.fib_table_hash[i]; 1202 struct hlist_node *tmp; 1203 struct fib_table *tb; 1204 1205 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) { 1206 hlist_del(&tb->tb_hlist); 1207 fib_table_flush(tb); 1208 fib_free_table(tb); 1209 } 1210 } 1211 1212 #ifdef CONFIG_IP_MULTIPLE_TABLES 1213 fib4_rules_exit(net); 1214 #endif 1215 rtnl_unlock(); 1216 kfree(net->ipv4.fib_table_hash); 1217 } 1218 1219 static int __net_init fib_net_init(struct net *net) 1220 { 1221 int error; 1222 1223 #ifdef CONFIG_IP_ROUTE_CLASSID 1224 net->ipv4.fib_num_tclassid_users = 0; 1225 #endif 1226 error = ip_fib_net_init(net); 1227 if (error < 0) 1228 goto out; 1229 error = nl_fib_lookup_init(net); 1230 if (error < 0) 1231 goto out_nlfl; 1232 error = fib_proc_init(net); 1233 if (error < 0) 1234 goto out_proc; 1235 out: 1236 return error; 1237 1238 out_proc: 1239 nl_fib_lookup_exit(net); 1240 out_nlfl: 1241 ip_fib_net_exit(net); 1242 goto out; 1243 } 1244 1245 static void __net_exit fib_net_exit(struct net *net) 1246 { 1247 fib_proc_exit(net); 1248 nl_fib_lookup_exit(net); 1249 ip_fib_net_exit(net); 1250 } 1251 1252 static struct pernet_operations fib_net_ops = { 1253 .init = fib_net_init, 1254 .exit = fib_net_exit, 1255 }; 1256 1257 void __init ip_fib_init(void) 1258 { 1259 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL); 1260 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL); 1261 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL); 1262 1263 register_pernet_subsys(&fib_net_ops); 1264 register_netdevice_notifier(&fib_netdev_notifier); 1265 register_inetaddr_notifier(&fib_inetaddr_notifier); 1266 1267 fib_trie_init(); 1268 } 1269