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 #include <net/l3mdev.h> 49 #include <trace/events/fib.h> 50 51 #ifndef CONFIG_IP_MULTIPLE_TABLES 52 53 static int __net_init fib4_rules_init(struct net *net) 54 { 55 struct fib_table *local_table, *main_table; 56 57 main_table = fib_trie_table(RT_TABLE_MAIN, NULL); 58 if (!main_table) 59 return -ENOMEM; 60 61 local_table = fib_trie_table(RT_TABLE_LOCAL, main_table); 62 if (!local_table) 63 goto fail; 64 65 hlist_add_head_rcu(&local_table->tb_hlist, 66 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]); 67 hlist_add_head_rcu(&main_table->tb_hlist, 68 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]); 69 return 0; 70 71 fail: 72 fib_free_table(main_table); 73 return -ENOMEM; 74 } 75 #else 76 77 struct fib_table *fib_new_table(struct net *net, u32 id) 78 { 79 struct fib_table *tb, *alias = NULL; 80 unsigned int h; 81 82 if (id == 0) 83 id = RT_TABLE_MAIN; 84 tb = fib_get_table(net, id); 85 if (tb) 86 return tb; 87 88 if (id == RT_TABLE_LOCAL) 89 alias = fib_new_table(net, RT_TABLE_MAIN); 90 91 tb = fib_trie_table(id, alias); 92 if (!tb) 93 return NULL; 94 95 switch (id) { 96 case RT_TABLE_LOCAL: 97 rcu_assign_pointer(net->ipv4.fib_local, tb); 98 break; 99 case RT_TABLE_MAIN: 100 rcu_assign_pointer(net->ipv4.fib_main, tb); 101 break; 102 case RT_TABLE_DEFAULT: 103 rcu_assign_pointer(net->ipv4.fib_default, tb); 104 break; 105 default: 106 break; 107 } 108 109 h = id & (FIB_TABLE_HASHSZ - 1); 110 hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]); 111 return tb; 112 } 113 114 /* caller must hold either rtnl or rcu read lock */ 115 struct fib_table *fib_get_table(struct net *net, u32 id) 116 { 117 struct fib_table *tb; 118 struct hlist_head *head; 119 unsigned int h; 120 121 if (id == 0) 122 id = RT_TABLE_MAIN; 123 h = id & (FIB_TABLE_HASHSZ - 1); 124 125 head = &net->ipv4.fib_table_hash[h]; 126 hlist_for_each_entry_rcu(tb, head, tb_hlist) { 127 if (tb->tb_id == id) 128 return tb; 129 } 130 return NULL; 131 } 132 #endif /* CONFIG_IP_MULTIPLE_TABLES */ 133 134 static void fib_replace_table(struct net *net, struct fib_table *old, 135 struct fib_table *new) 136 { 137 #ifdef CONFIG_IP_MULTIPLE_TABLES 138 switch (new->tb_id) { 139 case RT_TABLE_LOCAL: 140 rcu_assign_pointer(net->ipv4.fib_local, new); 141 break; 142 case RT_TABLE_MAIN: 143 rcu_assign_pointer(net->ipv4.fib_main, new); 144 break; 145 case RT_TABLE_DEFAULT: 146 rcu_assign_pointer(net->ipv4.fib_default, new); 147 break; 148 default: 149 break; 150 } 151 152 #endif 153 /* replace the old table in the hlist */ 154 hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist); 155 } 156 157 int fib_unmerge(struct net *net) 158 { 159 struct fib_table *old, *new; 160 161 /* attempt to fetch local table if it has been allocated */ 162 old = fib_get_table(net, RT_TABLE_LOCAL); 163 if (!old) 164 return 0; 165 166 new = fib_trie_unmerge(old); 167 if (!new) 168 return -ENOMEM; 169 170 /* replace merged table with clean table */ 171 if (new != old) { 172 fib_replace_table(net, old, new); 173 fib_free_table(old); 174 } 175 176 return 0; 177 } 178 179 static void fib_flush(struct net *net) 180 { 181 int flushed = 0; 182 unsigned int h; 183 184 for (h = 0; h < FIB_TABLE_HASHSZ; h++) { 185 struct hlist_head *head = &net->ipv4.fib_table_hash[h]; 186 struct hlist_node *tmp; 187 struct fib_table *tb; 188 189 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) 190 flushed += fib_table_flush(tb); 191 } 192 193 if (flushed) 194 rt_cache_flush(net); 195 } 196 197 void fib_flush_external(struct net *net) 198 { 199 struct fib_table *tb; 200 struct hlist_head *head; 201 unsigned int h; 202 203 for (h = 0; h < FIB_TABLE_HASHSZ; h++) { 204 head = &net->ipv4.fib_table_hash[h]; 205 hlist_for_each_entry(tb, head, tb_hlist) 206 fib_table_flush_external(tb); 207 } 208 } 209 210 /* 211 * Find address type as if only "dev" was present in the system. If 212 * on_dev is NULL then all interfaces are taken into consideration. 213 */ 214 static inline unsigned int __inet_dev_addr_type(struct net *net, 215 const struct net_device *dev, 216 __be32 addr, u32 tb_id) 217 { 218 struct flowi4 fl4 = { .daddr = addr }; 219 struct fib_result res; 220 unsigned int ret = RTN_BROADCAST; 221 struct fib_table *table; 222 223 if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr)) 224 return RTN_BROADCAST; 225 if (ipv4_is_multicast(addr)) 226 return RTN_MULTICAST; 227 228 rcu_read_lock(); 229 230 table = fib_get_table(net, tb_id); 231 if (table) { 232 ret = RTN_UNICAST; 233 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) { 234 if (!dev || dev == res.fi->fib_dev) 235 ret = res.type; 236 } 237 } 238 239 rcu_read_unlock(); 240 return ret; 241 } 242 243 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id) 244 { 245 return __inet_dev_addr_type(net, NULL, addr, tb_id); 246 } 247 EXPORT_SYMBOL(inet_addr_type_table); 248 249 unsigned int inet_addr_type(struct net *net, __be32 addr) 250 { 251 return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL); 252 } 253 EXPORT_SYMBOL(inet_addr_type); 254 255 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 256 __be32 addr) 257 { 258 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL; 259 260 return __inet_dev_addr_type(net, dev, addr, rt_table); 261 } 262 EXPORT_SYMBOL(inet_dev_addr_type); 263 264 /* inet_addr_type with dev == NULL but using the table from a dev 265 * if one is associated 266 */ 267 unsigned int inet_addr_type_dev_table(struct net *net, 268 const struct net_device *dev, 269 __be32 addr) 270 { 271 u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL; 272 273 return __inet_dev_addr_type(net, NULL, addr, rt_table); 274 } 275 EXPORT_SYMBOL(inet_addr_type_dev_table); 276 277 __be32 fib_compute_spec_dst(struct sk_buff *skb) 278 { 279 struct net_device *dev = skb->dev; 280 struct in_device *in_dev; 281 struct fib_result res; 282 struct rtable *rt; 283 struct net *net; 284 int scope; 285 286 rt = skb_rtable(skb); 287 if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) == 288 RTCF_LOCAL) 289 return ip_hdr(skb)->daddr; 290 291 in_dev = __in_dev_get_rcu(dev); 292 BUG_ON(!in_dev); 293 294 net = dev_net(dev); 295 296 scope = RT_SCOPE_UNIVERSE; 297 if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) { 298 struct flowi4 fl4 = { 299 .flowi4_iif = LOOPBACK_IFINDEX, 300 .daddr = ip_hdr(skb)->saddr, 301 .flowi4_tos = RT_TOS(ip_hdr(skb)->tos), 302 .flowi4_scope = scope, 303 .flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0, 304 }; 305 if (!fib_lookup(net, &fl4, &res, 0)) 306 return FIB_RES_PREFSRC(net, res); 307 } else { 308 scope = RT_SCOPE_LINK; 309 } 310 311 return inet_select_addr(dev, ip_hdr(skb)->saddr, scope); 312 } 313 314 /* Given (packet source, input interface) and optional (dst, oif, tos): 315 * - (main) check, that source is valid i.e. not broadcast or our local 316 * address. 317 * - figure out what "logical" interface this packet arrived 318 * and calculate "specific destination" address. 319 * - check, that packet arrived from expected physical interface. 320 * called with rcu_read_lock() 321 */ 322 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, 323 u8 tos, int oif, struct net_device *dev, 324 int rpf, struct in_device *idev, u32 *itag) 325 { 326 int ret, no_addr; 327 struct fib_result res; 328 struct flowi4 fl4; 329 struct net *net; 330 bool dev_match; 331 332 fl4.flowi4_oif = 0; 333 fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev); 334 if (!fl4.flowi4_iif) 335 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX; 336 fl4.daddr = src; 337 fl4.saddr = dst; 338 fl4.flowi4_tos = tos; 339 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 340 fl4.flowi4_tun_key.tun_id = 0; 341 fl4.flowi4_flags = 0; 342 343 no_addr = idev->ifa_list == NULL; 344 345 fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0; 346 347 trace_fib_validate_source(dev, &fl4); 348 349 net = dev_net(dev); 350 if (fib_lookup(net, &fl4, &res, 0)) 351 goto last_resort; 352 if (res.type != RTN_UNICAST && 353 (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev))) 354 goto e_inval; 355 if (!rpf && !fib_num_tclassid_users(dev_net(dev)) && 356 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) 357 goto last_resort; 358 fib_combine_itag(itag, &res); 359 dev_match = false; 360 361 #ifdef CONFIG_IP_ROUTE_MULTIPATH 362 for (ret = 0; ret < res.fi->fib_nhs; ret++) { 363 struct fib_nh *nh = &res.fi->fib_nh[ret]; 364 365 if (nh->nh_dev == dev) { 366 dev_match = true; 367 break; 368 } else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) { 369 dev_match = true; 370 break; 371 } 372 } 373 #else 374 if (FIB_RES_DEV(res) == dev) 375 dev_match = true; 376 #endif 377 if (dev_match) { 378 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; 379 return ret; 380 } 381 if (no_addr) 382 goto last_resort; 383 if (rpf == 1) 384 goto e_rpf; 385 fl4.flowi4_oif = dev->ifindex; 386 387 ret = 0; 388 if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) { 389 if (res.type == RTN_UNICAST) 390 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; 391 } 392 return ret; 393 394 last_resort: 395 if (rpf) 396 goto e_rpf; 397 *itag = 0; 398 return 0; 399 400 e_inval: 401 return -EINVAL; 402 e_rpf: 403 return -EXDEV; 404 } 405 406 /* Ignore rp_filter for packets protected by IPsec. */ 407 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, 408 u8 tos, int oif, struct net_device *dev, 409 struct in_device *idev, u32 *itag) 410 { 411 int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev); 412 413 if (!r && !fib_num_tclassid_users(dev_net(dev)) && 414 IN_DEV_ACCEPT_LOCAL(idev) && 415 (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) { 416 *itag = 0; 417 return 0; 418 } 419 return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag); 420 } 421 422 static inline __be32 sk_extract_addr(struct sockaddr *addr) 423 { 424 return ((struct sockaddr_in *) addr)->sin_addr.s_addr; 425 } 426 427 static int put_rtax(struct nlattr *mx, int len, int type, u32 value) 428 { 429 struct nlattr *nla; 430 431 nla = (struct nlattr *) ((char *) mx + len); 432 nla->nla_type = type; 433 nla->nla_len = nla_attr_size(4); 434 *(u32 *) nla_data(nla) = value; 435 436 return len + nla_total_size(4); 437 } 438 439 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt, 440 struct fib_config *cfg) 441 { 442 __be32 addr; 443 int plen; 444 445 memset(cfg, 0, sizeof(*cfg)); 446 cfg->fc_nlinfo.nl_net = net; 447 448 if (rt->rt_dst.sa_family != AF_INET) 449 return -EAFNOSUPPORT; 450 451 /* 452 * Check mask for validity: 453 * a) it must be contiguous. 454 * b) destination must have all host bits clear. 455 * c) if application forgot to set correct family (AF_INET), 456 * reject request unless it is absolutely clear i.e. 457 * both family and mask are zero. 458 */ 459 plen = 32; 460 addr = sk_extract_addr(&rt->rt_dst); 461 if (!(rt->rt_flags & RTF_HOST)) { 462 __be32 mask = sk_extract_addr(&rt->rt_genmask); 463 464 if (rt->rt_genmask.sa_family != AF_INET) { 465 if (mask || rt->rt_genmask.sa_family) 466 return -EAFNOSUPPORT; 467 } 468 469 if (bad_mask(mask, addr)) 470 return -EINVAL; 471 472 plen = inet_mask_len(mask); 473 } 474 475 cfg->fc_dst_len = plen; 476 cfg->fc_dst = addr; 477 478 if (cmd != SIOCDELRT) { 479 cfg->fc_nlflags = NLM_F_CREATE; 480 cfg->fc_protocol = RTPROT_BOOT; 481 } 482 483 if (rt->rt_metric) 484 cfg->fc_priority = rt->rt_metric - 1; 485 486 if (rt->rt_flags & RTF_REJECT) { 487 cfg->fc_scope = RT_SCOPE_HOST; 488 cfg->fc_type = RTN_UNREACHABLE; 489 return 0; 490 } 491 492 cfg->fc_scope = RT_SCOPE_NOWHERE; 493 cfg->fc_type = RTN_UNICAST; 494 495 if (rt->rt_dev) { 496 char *colon; 497 struct net_device *dev; 498 char devname[IFNAMSIZ]; 499 500 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1)) 501 return -EFAULT; 502 503 devname[IFNAMSIZ-1] = 0; 504 colon = strchr(devname, ':'); 505 if (colon) 506 *colon = 0; 507 dev = __dev_get_by_name(net, devname); 508 if (!dev) 509 return -ENODEV; 510 cfg->fc_oif = dev->ifindex; 511 if (colon) { 512 struct in_ifaddr *ifa; 513 struct in_device *in_dev = __in_dev_get_rtnl(dev); 514 if (!in_dev) 515 return -ENODEV; 516 *colon = ':'; 517 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) 518 if (strcmp(ifa->ifa_label, devname) == 0) 519 break; 520 if (!ifa) 521 return -ENODEV; 522 cfg->fc_prefsrc = ifa->ifa_local; 523 } 524 } 525 526 addr = sk_extract_addr(&rt->rt_gateway); 527 if (rt->rt_gateway.sa_family == AF_INET && addr) { 528 unsigned int addr_type; 529 530 cfg->fc_gw = addr; 531 addr_type = inet_addr_type_table(net, addr, cfg->fc_table); 532 if (rt->rt_flags & RTF_GATEWAY && 533 addr_type == RTN_UNICAST) 534 cfg->fc_scope = RT_SCOPE_UNIVERSE; 535 } 536 537 if (cmd == SIOCDELRT) 538 return 0; 539 540 if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw) 541 return -EINVAL; 542 543 if (cfg->fc_scope == RT_SCOPE_NOWHERE) 544 cfg->fc_scope = RT_SCOPE_LINK; 545 546 if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) { 547 struct nlattr *mx; 548 int len = 0; 549 550 mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL); 551 if (!mx) 552 return -ENOMEM; 553 554 if (rt->rt_flags & RTF_MTU) 555 len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40); 556 557 if (rt->rt_flags & RTF_WINDOW) 558 len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window); 559 560 if (rt->rt_flags & RTF_IRTT) 561 len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3); 562 563 cfg->fc_mx = mx; 564 cfg->fc_mx_len = len; 565 } 566 567 return 0; 568 } 569 570 /* 571 * Handle IP routing ioctl calls. 572 * These are used to manipulate the routing tables 573 */ 574 int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg) 575 { 576 struct fib_config cfg; 577 struct rtentry rt; 578 int err; 579 580 switch (cmd) { 581 case SIOCADDRT: /* Add a route */ 582 case SIOCDELRT: /* Delete a route */ 583 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 584 return -EPERM; 585 586 if (copy_from_user(&rt, arg, sizeof(rt))) 587 return -EFAULT; 588 589 rtnl_lock(); 590 err = rtentry_to_fib_config(net, cmd, &rt, &cfg); 591 if (err == 0) { 592 struct fib_table *tb; 593 594 if (cmd == SIOCDELRT) { 595 tb = fib_get_table(net, cfg.fc_table); 596 if (tb) 597 err = fib_table_delete(tb, &cfg); 598 else 599 err = -ESRCH; 600 } else { 601 tb = fib_new_table(net, cfg.fc_table); 602 if (tb) 603 err = fib_table_insert(tb, &cfg); 604 else 605 err = -ENOBUFS; 606 } 607 608 /* allocated by rtentry_to_fib_config() */ 609 kfree(cfg.fc_mx); 610 } 611 rtnl_unlock(); 612 return err; 613 } 614 return -EINVAL; 615 } 616 617 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = { 618 [RTA_DST] = { .type = NLA_U32 }, 619 [RTA_SRC] = { .type = NLA_U32 }, 620 [RTA_IIF] = { .type = NLA_U32 }, 621 [RTA_OIF] = { .type = NLA_U32 }, 622 [RTA_GATEWAY] = { .type = NLA_U32 }, 623 [RTA_PRIORITY] = { .type = NLA_U32 }, 624 [RTA_PREFSRC] = { .type = NLA_U32 }, 625 [RTA_METRICS] = { .type = NLA_NESTED }, 626 [RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) }, 627 [RTA_FLOW] = { .type = NLA_U32 }, 628 [RTA_ENCAP_TYPE] = { .type = NLA_U16 }, 629 [RTA_ENCAP] = { .type = NLA_NESTED }, 630 }; 631 632 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, 633 struct nlmsghdr *nlh, struct fib_config *cfg) 634 { 635 struct nlattr *attr; 636 int err, remaining; 637 struct rtmsg *rtm; 638 639 err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy); 640 if (err < 0) 641 goto errout; 642 643 memset(cfg, 0, sizeof(*cfg)); 644 645 rtm = nlmsg_data(nlh); 646 cfg->fc_dst_len = rtm->rtm_dst_len; 647 cfg->fc_tos = rtm->rtm_tos; 648 cfg->fc_table = rtm->rtm_table; 649 cfg->fc_protocol = rtm->rtm_protocol; 650 cfg->fc_scope = rtm->rtm_scope; 651 cfg->fc_type = rtm->rtm_type; 652 cfg->fc_flags = rtm->rtm_flags; 653 cfg->fc_nlflags = nlh->nlmsg_flags; 654 655 cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid; 656 cfg->fc_nlinfo.nlh = nlh; 657 cfg->fc_nlinfo.nl_net = net; 658 659 if (cfg->fc_type > RTN_MAX) { 660 err = -EINVAL; 661 goto errout; 662 } 663 664 nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) { 665 switch (nla_type(attr)) { 666 case RTA_DST: 667 cfg->fc_dst = nla_get_be32(attr); 668 break; 669 case RTA_OIF: 670 cfg->fc_oif = nla_get_u32(attr); 671 break; 672 case RTA_GATEWAY: 673 cfg->fc_gw = nla_get_be32(attr); 674 break; 675 case RTA_PRIORITY: 676 cfg->fc_priority = nla_get_u32(attr); 677 break; 678 case RTA_PREFSRC: 679 cfg->fc_prefsrc = nla_get_be32(attr); 680 break; 681 case RTA_METRICS: 682 cfg->fc_mx = nla_data(attr); 683 cfg->fc_mx_len = nla_len(attr); 684 break; 685 case RTA_MULTIPATH: 686 cfg->fc_mp = nla_data(attr); 687 cfg->fc_mp_len = nla_len(attr); 688 break; 689 case RTA_FLOW: 690 cfg->fc_flow = nla_get_u32(attr); 691 break; 692 case RTA_TABLE: 693 cfg->fc_table = nla_get_u32(attr); 694 break; 695 case RTA_ENCAP: 696 cfg->fc_encap = attr; 697 break; 698 case RTA_ENCAP_TYPE: 699 cfg->fc_encap_type = nla_get_u16(attr); 700 break; 701 } 702 } 703 704 return 0; 705 errout: 706 return err; 707 } 708 709 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh) 710 { 711 struct net *net = sock_net(skb->sk); 712 struct fib_config cfg; 713 struct fib_table *tb; 714 int err; 715 716 err = rtm_to_fib_config(net, skb, nlh, &cfg); 717 if (err < 0) 718 goto errout; 719 720 tb = fib_get_table(net, cfg.fc_table); 721 if (!tb) { 722 err = -ESRCH; 723 goto errout; 724 } 725 726 err = fib_table_delete(tb, &cfg); 727 errout: 728 return err; 729 } 730 731 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh) 732 { 733 struct net *net = sock_net(skb->sk); 734 struct fib_config cfg; 735 struct fib_table *tb; 736 int err; 737 738 err = rtm_to_fib_config(net, skb, nlh, &cfg); 739 if (err < 0) 740 goto errout; 741 742 tb = fib_new_table(net, cfg.fc_table); 743 if (!tb) { 744 err = -ENOBUFS; 745 goto errout; 746 } 747 748 err = fib_table_insert(tb, &cfg); 749 errout: 750 return err; 751 } 752 753 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) 754 { 755 struct net *net = sock_net(skb->sk); 756 unsigned int h, s_h; 757 unsigned int e = 0, s_e; 758 struct fib_table *tb; 759 struct hlist_head *head; 760 int dumped = 0; 761 762 if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) && 763 ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED) 764 return skb->len; 765 766 s_h = cb->args[0]; 767 s_e = cb->args[1]; 768 769 rcu_read_lock(); 770 771 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) { 772 e = 0; 773 head = &net->ipv4.fib_table_hash[h]; 774 hlist_for_each_entry_rcu(tb, head, tb_hlist) { 775 if (e < s_e) 776 goto next; 777 if (dumped) 778 memset(&cb->args[2], 0, sizeof(cb->args) - 779 2 * sizeof(cb->args[0])); 780 if (fib_table_dump(tb, skb, cb) < 0) 781 goto out; 782 dumped = 1; 783 next: 784 e++; 785 } 786 } 787 out: 788 rcu_read_unlock(); 789 790 cb->args[1] = e; 791 cb->args[0] = h; 792 793 return skb->len; 794 } 795 796 /* Prepare and feed intra-kernel routing request. 797 * Really, it should be netlink message, but :-( netlink 798 * can be not configured, so that we feed it directly 799 * to fib engine. It is legal, because all events occur 800 * only when netlink is already locked. 801 */ 802 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa) 803 { 804 struct net *net = dev_net(ifa->ifa_dev->dev); 805 u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev); 806 struct fib_table *tb; 807 struct fib_config cfg = { 808 .fc_protocol = RTPROT_KERNEL, 809 .fc_type = type, 810 .fc_dst = dst, 811 .fc_dst_len = dst_len, 812 .fc_prefsrc = ifa->ifa_local, 813 .fc_oif = ifa->ifa_dev->dev->ifindex, 814 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND, 815 .fc_nlinfo = { 816 .nl_net = net, 817 }, 818 }; 819 820 if (!tb_id) 821 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL; 822 823 tb = fib_new_table(net, tb_id); 824 if (!tb) 825 return; 826 827 cfg.fc_table = tb->tb_id; 828 829 if (type != RTN_LOCAL) 830 cfg.fc_scope = RT_SCOPE_LINK; 831 else 832 cfg.fc_scope = RT_SCOPE_HOST; 833 834 if (cmd == RTM_NEWROUTE) 835 fib_table_insert(tb, &cfg); 836 else 837 fib_table_delete(tb, &cfg); 838 } 839 840 void fib_add_ifaddr(struct in_ifaddr *ifa) 841 { 842 struct in_device *in_dev = ifa->ifa_dev; 843 struct net_device *dev = in_dev->dev; 844 struct in_ifaddr *prim = ifa; 845 __be32 mask = ifa->ifa_mask; 846 __be32 addr = ifa->ifa_local; 847 __be32 prefix = ifa->ifa_address & mask; 848 849 if (ifa->ifa_flags & IFA_F_SECONDARY) { 850 prim = inet_ifa_byprefix(in_dev, prefix, mask); 851 if (!prim) { 852 pr_warn("%s: bug: prim == NULL\n", __func__); 853 return; 854 } 855 } 856 857 fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim); 858 859 if (!(dev->flags & IFF_UP)) 860 return; 861 862 /* Add broadcast address, if it is explicitly assigned. */ 863 if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) 864 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); 865 866 if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) && 867 (prefix != addr || ifa->ifa_prefixlen < 32)) { 868 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE)) 869 fib_magic(RTM_NEWROUTE, 870 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, 871 prefix, ifa->ifa_prefixlen, prim); 872 873 /* Add network specific broadcasts, when it takes a sense */ 874 if (ifa->ifa_prefixlen < 31) { 875 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim); 876 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask, 877 32, prim); 878 } 879 } 880 } 881 882 /* Delete primary or secondary address. 883 * Optionally, on secondary address promotion consider the addresses 884 * from subnet iprim as deleted, even if they are in device list. 885 * In this case the secondary ifa can be in device list. 886 */ 887 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) 888 { 889 struct in_device *in_dev = ifa->ifa_dev; 890 struct net_device *dev = in_dev->dev; 891 struct in_ifaddr *ifa1; 892 struct in_ifaddr *prim = ifa, *prim1 = NULL; 893 __be32 brd = ifa->ifa_address | ~ifa->ifa_mask; 894 __be32 any = ifa->ifa_address & ifa->ifa_mask; 895 #define LOCAL_OK 1 896 #define BRD_OK 2 897 #define BRD0_OK 4 898 #define BRD1_OK 8 899 unsigned int ok = 0; 900 int subnet = 0; /* Primary network */ 901 int gone = 1; /* Address is missing */ 902 int same_prefsrc = 0; /* Another primary with same IP */ 903 904 if (ifa->ifa_flags & IFA_F_SECONDARY) { 905 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask); 906 if (!prim) { 907 /* if the device has been deleted, we don't perform 908 * address promotion 909 */ 910 if (!in_dev->dead) 911 pr_warn("%s: bug: prim == NULL\n", __func__); 912 return; 913 } 914 if (iprim && iprim != prim) { 915 pr_warn("%s: bug: iprim != prim\n", __func__); 916 return; 917 } 918 } else if (!ipv4_is_zeronet(any) && 919 (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) { 920 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE)) 921 fib_magic(RTM_DELROUTE, 922 dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, 923 any, ifa->ifa_prefixlen, prim); 924 subnet = 1; 925 } 926 927 if (in_dev->dead) 928 goto no_promotions; 929 930 /* Deletion is more complicated than add. 931 * We should take care of not to delete too much :-) 932 * 933 * Scan address list to be sure that addresses are really gone. 934 */ 935 936 for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) { 937 if (ifa1 == ifa) { 938 /* promotion, keep the IP */ 939 gone = 0; 940 continue; 941 } 942 /* Ignore IFAs from our subnet */ 943 if (iprim && ifa1->ifa_mask == iprim->ifa_mask && 944 inet_ifa_match(ifa1->ifa_address, iprim)) 945 continue; 946 947 /* Ignore ifa1 if it uses different primary IP (prefsrc) */ 948 if (ifa1->ifa_flags & IFA_F_SECONDARY) { 949 /* Another address from our subnet? */ 950 if (ifa1->ifa_mask == prim->ifa_mask && 951 inet_ifa_match(ifa1->ifa_address, prim)) 952 prim1 = prim; 953 else { 954 /* We reached the secondaries, so 955 * same_prefsrc should be determined. 956 */ 957 if (!same_prefsrc) 958 continue; 959 /* Search new prim1 if ifa1 is not 960 * using the current prim1 961 */ 962 if (!prim1 || 963 ifa1->ifa_mask != prim1->ifa_mask || 964 !inet_ifa_match(ifa1->ifa_address, prim1)) 965 prim1 = inet_ifa_byprefix(in_dev, 966 ifa1->ifa_address, 967 ifa1->ifa_mask); 968 if (!prim1) 969 continue; 970 if (prim1->ifa_local != prim->ifa_local) 971 continue; 972 } 973 } else { 974 if (prim->ifa_local != ifa1->ifa_local) 975 continue; 976 prim1 = ifa1; 977 if (prim != prim1) 978 same_prefsrc = 1; 979 } 980 if (ifa->ifa_local == ifa1->ifa_local) 981 ok |= LOCAL_OK; 982 if (ifa->ifa_broadcast == ifa1->ifa_broadcast) 983 ok |= BRD_OK; 984 if (brd == ifa1->ifa_broadcast) 985 ok |= BRD1_OK; 986 if (any == ifa1->ifa_broadcast) 987 ok |= BRD0_OK; 988 /* primary has network specific broadcasts */ 989 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) { 990 __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask; 991 __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask; 992 993 if (!ipv4_is_zeronet(any1)) { 994 if (ifa->ifa_broadcast == brd1 || 995 ifa->ifa_broadcast == any1) 996 ok |= BRD_OK; 997 if (brd == brd1 || brd == any1) 998 ok |= BRD1_OK; 999 if (any == brd1 || any == any1) 1000 ok |= BRD0_OK; 1001 } 1002 } 1003 } 1004 1005 no_promotions: 1006 if (!(ok & BRD_OK)) 1007 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); 1008 if (subnet && ifa->ifa_prefixlen < 31) { 1009 if (!(ok & BRD1_OK)) 1010 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim); 1011 if (!(ok & BRD0_OK)) 1012 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim); 1013 } 1014 if (!(ok & LOCAL_OK)) { 1015 unsigned int addr_type; 1016 1017 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim); 1018 1019 /* Check, that this local address finally disappeared. */ 1020 addr_type = inet_addr_type_dev_table(dev_net(dev), dev, 1021 ifa->ifa_local); 1022 if (gone && addr_type != RTN_LOCAL) { 1023 /* And the last, but not the least thing. 1024 * We must flush stray FIB entries. 1025 * 1026 * First of all, we scan fib_info list searching 1027 * for stray nexthop entries, then ignite fib_flush. 1028 */ 1029 if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local)) 1030 fib_flush(dev_net(dev)); 1031 } 1032 } 1033 #undef LOCAL_OK 1034 #undef BRD_OK 1035 #undef BRD0_OK 1036 #undef BRD1_OK 1037 } 1038 1039 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn) 1040 { 1041 1042 struct fib_result res; 1043 struct flowi4 fl4 = { 1044 .flowi4_mark = frn->fl_mark, 1045 .daddr = frn->fl_addr, 1046 .flowi4_tos = frn->fl_tos, 1047 .flowi4_scope = frn->fl_scope, 1048 }; 1049 struct fib_table *tb; 1050 1051 rcu_read_lock(); 1052 1053 tb = fib_get_table(net, frn->tb_id_in); 1054 1055 frn->err = -ENOENT; 1056 if (tb) { 1057 local_bh_disable(); 1058 1059 frn->tb_id = tb->tb_id; 1060 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF); 1061 1062 if (!frn->err) { 1063 frn->prefixlen = res.prefixlen; 1064 frn->nh_sel = res.nh_sel; 1065 frn->type = res.type; 1066 frn->scope = res.scope; 1067 } 1068 local_bh_enable(); 1069 } 1070 1071 rcu_read_unlock(); 1072 } 1073 1074 static void nl_fib_input(struct sk_buff *skb) 1075 { 1076 struct net *net; 1077 struct fib_result_nl *frn; 1078 struct nlmsghdr *nlh; 1079 u32 portid; 1080 1081 net = sock_net(skb->sk); 1082 nlh = nlmsg_hdr(skb); 1083 if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len || 1084 nlmsg_len(nlh) < sizeof(*frn)) 1085 return; 1086 1087 skb = netlink_skb_clone(skb, GFP_KERNEL); 1088 if (!skb) 1089 return; 1090 nlh = nlmsg_hdr(skb); 1091 1092 frn = (struct fib_result_nl *) nlmsg_data(nlh); 1093 nl_fib_lookup(net, frn); 1094 1095 portid = NETLINK_CB(skb).portid; /* netlink portid */ 1096 NETLINK_CB(skb).portid = 0; /* from kernel */ 1097 NETLINK_CB(skb).dst_group = 0; /* unicast */ 1098 netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT); 1099 } 1100 1101 static int __net_init nl_fib_lookup_init(struct net *net) 1102 { 1103 struct sock *sk; 1104 struct netlink_kernel_cfg cfg = { 1105 .input = nl_fib_input, 1106 }; 1107 1108 sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg); 1109 if (!sk) 1110 return -EAFNOSUPPORT; 1111 net->ipv4.fibnl = sk; 1112 return 0; 1113 } 1114 1115 static void nl_fib_lookup_exit(struct net *net) 1116 { 1117 netlink_kernel_release(net->ipv4.fibnl); 1118 net->ipv4.fibnl = NULL; 1119 } 1120 1121 static void fib_disable_ip(struct net_device *dev, unsigned long event, 1122 bool force) 1123 { 1124 if (fib_sync_down_dev(dev, event, force)) 1125 fib_flush(dev_net(dev)); 1126 rt_cache_flush(dev_net(dev)); 1127 arp_ifdown(dev); 1128 } 1129 1130 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr) 1131 { 1132 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr; 1133 struct net_device *dev = ifa->ifa_dev->dev; 1134 struct net *net = dev_net(dev); 1135 1136 switch (event) { 1137 case NETDEV_UP: 1138 fib_add_ifaddr(ifa); 1139 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1140 fib_sync_up(dev, RTNH_F_DEAD); 1141 #endif 1142 atomic_inc(&net->ipv4.dev_addr_genid); 1143 rt_cache_flush(dev_net(dev)); 1144 break; 1145 case NETDEV_DOWN: 1146 fib_del_ifaddr(ifa, NULL); 1147 atomic_inc(&net->ipv4.dev_addr_genid); 1148 if (!ifa->ifa_dev->ifa_list) { 1149 /* Last address was deleted from this interface. 1150 * Disable IP. 1151 */ 1152 fib_disable_ip(dev, event, true); 1153 } else { 1154 rt_cache_flush(dev_net(dev)); 1155 } 1156 break; 1157 } 1158 return NOTIFY_DONE; 1159 } 1160 1161 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) 1162 { 1163 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1164 struct netdev_notifier_changeupper_info *info; 1165 struct in_device *in_dev; 1166 struct net *net = dev_net(dev); 1167 unsigned int flags; 1168 1169 if (event == NETDEV_UNREGISTER) { 1170 fib_disable_ip(dev, event, true); 1171 rt_flush_dev(dev); 1172 return NOTIFY_DONE; 1173 } 1174 1175 in_dev = __in_dev_get_rtnl(dev); 1176 if (!in_dev) 1177 return NOTIFY_DONE; 1178 1179 switch (event) { 1180 case NETDEV_UP: 1181 for_ifa(in_dev) { 1182 fib_add_ifaddr(ifa); 1183 } endfor_ifa(in_dev); 1184 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1185 fib_sync_up(dev, RTNH_F_DEAD); 1186 #endif 1187 atomic_inc(&net->ipv4.dev_addr_genid); 1188 rt_cache_flush(net); 1189 break; 1190 case NETDEV_DOWN: 1191 fib_disable_ip(dev, event, false); 1192 break; 1193 case NETDEV_CHANGE: 1194 flags = dev_get_flags(dev); 1195 if (flags & (IFF_RUNNING | IFF_LOWER_UP)) 1196 fib_sync_up(dev, RTNH_F_LINKDOWN); 1197 else 1198 fib_sync_down_dev(dev, event, false); 1199 /* fall through */ 1200 case NETDEV_CHANGEMTU: 1201 rt_cache_flush(net); 1202 break; 1203 case NETDEV_CHANGEUPPER: 1204 info = ptr; 1205 /* flush all routes if dev is linked to or unlinked from 1206 * an L3 master device (e.g., VRF) 1207 */ 1208 if (info->upper_dev && netif_is_l3_master(info->upper_dev)) 1209 fib_disable_ip(dev, NETDEV_DOWN, true); 1210 break; 1211 } 1212 return NOTIFY_DONE; 1213 } 1214 1215 static struct notifier_block fib_inetaddr_notifier = { 1216 .notifier_call = fib_inetaddr_event, 1217 }; 1218 1219 static struct notifier_block fib_netdev_notifier = { 1220 .notifier_call = fib_netdev_event, 1221 }; 1222 1223 static int __net_init ip_fib_net_init(struct net *net) 1224 { 1225 int err; 1226 size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ; 1227 1228 /* Avoid false sharing : Use at least a full cache line */ 1229 size = max_t(size_t, size, L1_CACHE_BYTES); 1230 1231 net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL); 1232 if (!net->ipv4.fib_table_hash) 1233 return -ENOMEM; 1234 1235 err = fib4_rules_init(net); 1236 if (err < 0) 1237 goto fail; 1238 return 0; 1239 1240 fail: 1241 kfree(net->ipv4.fib_table_hash); 1242 return err; 1243 } 1244 1245 static void ip_fib_net_exit(struct net *net) 1246 { 1247 unsigned int i; 1248 1249 rtnl_lock(); 1250 #ifdef CONFIG_IP_MULTIPLE_TABLES 1251 RCU_INIT_POINTER(net->ipv4.fib_local, NULL); 1252 RCU_INIT_POINTER(net->ipv4.fib_main, NULL); 1253 RCU_INIT_POINTER(net->ipv4.fib_default, NULL); 1254 #endif 1255 for (i = 0; i < FIB_TABLE_HASHSZ; i++) { 1256 struct hlist_head *head = &net->ipv4.fib_table_hash[i]; 1257 struct hlist_node *tmp; 1258 struct fib_table *tb; 1259 1260 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) { 1261 hlist_del(&tb->tb_hlist); 1262 fib_table_flush(tb); 1263 fib_free_table(tb); 1264 } 1265 } 1266 1267 #ifdef CONFIG_IP_MULTIPLE_TABLES 1268 fib4_rules_exit(net); 1269 #endif 1270 rtnl_unlock(); 1271 kfree(net->ipv4.fib_table_hash); 1272 } 1273 1274 static int __net_init fib_net_init(struct net *net) 1275 { 1276 int error; 1277 1278 #ifdef CONFIG_IP_ROUTE_CLASSID 1279 net->ipv4.fib_num_tclassid_users = 0; 1280 #endif 1281 error = ip_fib_net_init(net); 1282 if (error < 0) 1283 goto out; 1284 error = nl_fib_lookup_init(net); 1285 if (error < 0) 1286 goto out_nlfl; 1287 error = fib_proc_init(net); 1288 if (error < 0) 1289 goto out_proc; 1290 out: 1291 return error; 1292 1293 out_proc: 1294 nl_fib_lookup_exit(net); 1295 out_nlfl: 1296 ip_fib_net_exit(net); 1297 goto out; 1298 } 1299 1300 static void __net_exit fib_net_exit(struct net *net) 1301 { 1302 fib_proc_exit(net); 1303 nl_fib_lookup_exit(net); 1304 ip_fib_net_exit(net); 1305 } 1306 1307 static struct pernet_operations fib_net_ops = { 1308 .init = fib_net_init, 1309 .exit = fib_net_exit, 1310 }; 1311 1312 void __init ip_fib_init(void) 1313 { 1314 rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL); 1315 rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL); 1316 rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL); 1317 1318 register_pernet_subsys(&fib_net_ops); 1319 register_netdevice_notifier(&fib_netdev_notifier); 1320 register_inetaddr_notifier(&fib_inetaddr_notifier); 1321 1322 fib_trie_init(); 1323 } 1324