net/ipv4/fib_frontend.c

   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 <linux/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 <net/lwtunnel.h>
  50 #include <trace/events/fib.h>
  51
  52 #ifndef CONFIG_IP_MULTIPLE_TABLES
  53
  54 static int __net_init fib4_rules_init(struct net *net)
  55 {
  56         struct fib_table *local_table, *main_table;
  57
  58         main_table  = fib_trie_table(RT_TABLE_MAIN, NULL);
  59         if (!main_table)
  60                 return -ENOMEM;
  61
  62         local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
  63         if (!local_table)
  64                 goto fail;
  65
  66         hlist_add_head_rcu(&local_table->tb_hlist,
  67                                 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
  68         hlist_add_head_rcu(&main_table->tb_hlist,
  69                                 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
  70         return 0;
  71
  72 fail:
  73         fib_free_table(main_table);
  74         return -ENOMEM;
  75 }
  76
  77 static bool fib4_has_custom_rules(struct net *net)
  78 {
  79         return false;
  80 }
  81 #else
  82
  83 struct fib_table *fib_new_table(struct net *net, u32 id)
  84 {
  85         struct fib_table *tb, *alias = NULL;
  86         unsigned int h;
  87
  88         if (id == 0)
  89                 id = RT_TABLE_MAIN;
  90         tb = fib_get_table(net, id);
  91         if (tb)
  92                 return tb;
  93
  94         if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
  95                 alias = fib_new_table(net, RT_TABLE_MAIN);
  96
  97         tb = fib_trie_table(id, alias);
  98         if (!tb)
  99                 return NULL;
 100
 101         switch (id) {
 102         case RT_TABLE_MAIN:
 103                 rcu_assign_pointer(net->ipv4.fib_main, tb);
 104                 break;
 105         case RT_TABLE_DEFAULT:
 106                 rcu_assign_pointer(net->ipv4.fib_default, tb);
 107                 break;
 108         default:
 109                 break;
 110         }
 111
 112         h = id & (FIB_TABLE_HASHSZ - 1);
 113         hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
 114         return tb;
 115 }
 116 EXPORT_SYMBOL_GPL(fib_new_table);
 117
 118 /* caller must hold either rtnl or rcu read lock */
 119 struct fib_table *fib_get_table(struct net *net, u32 id)
 120 {
 121         struct fib_table *tb;
 122         struct hlist_head *head;
 123         unsigned int h;
 124
 125         if (id == 0)
 126                 id = RT_TABLE_MAIN;
 127         h = id & (FIB_TABLE_HASHSZ - 1);
 128
 129         head = &net->ipv4.fib_table_hash[h];
 130         hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 131                 if (tb->tb_id == id)
 132                         return tb;
 133         }
 134         return NULL;
 135 }
 136
 137 static bool fib4_has_custom_rules(struct net *net)
 138 {
 139         return net->ipv4.fib_has_custom_rules;
 140 }
 141 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 142
 143 static void fib_replace_table(struct net *net, struct fib_table *old,
 144                               struct fib_table *new)
 145 {
 146 #ifdef CONFIG_IP_MULTIPLE_TABLES
 147         switch (new->tb_id) {
 148         case RT_TABLE_MAIN:
 149                 rcu_assign_pointer(net->ipv4.fib_main, new);
 150                 break;
 151         case RT_TABLE_DEFAULT:
 152                 rcu_assign_pointer(net->ipv4.fib_default, new);
 153                 break;
 154         default:
 155                 break;
 156         }
 157
 158 #endif
 159         /* replace the old table in the hlist */
 160         hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
 161 }
 162
 163 int fib_unmerge(struct net *net)
 164 {
 165         struct fib_table *old, *new, *main_table;
 166
 167         /* attempt to fetch local table if it has been allocated */
 168         old = fib_get_table(net, RT_TABLE_LOCAL);
 169         if (!old)
 170                 return 0;
 171
 172         new = fib_trie_unmerge(old);
 173         if (!new)
 174                 return -ENOMEM;
 175
 176         /* table is already unmerged */
 177         if (new == old)
 178                 return 0;
 179
 180         /* replace merged table with clean table */
 181         fib_replace_table(net, old, new);
 182         fib_free_table(old);
 183
 184         /* attempt to fetch main table if it has been allocated */
 185         main_table = fib_get_table(net, RT_TABLE_MAIN);
 186         if (!main_table)
 187                 return 0;
 188
 189         /* flush local entries from main table */
 190         fib_table_flush_external(main_table);
 191
 192         return 0;
 193 }
 194
 195 static void fib_flush(struct net *net)
 196 {
 197         int flushed = 0;
 198         unsigned int h;
 199
 200         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 201                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
 202                 struct hlist_node *tmp;
 203                 struct fib_table *tb;
 204
 205                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
 206                         flushed += fib_table_flush(net, tb);
 207         }
 208
 209         if (flushed)
 210                 rt_cache_flush(net);
 211 }
 212
 213 /*
 214  * Find address type as if only "dev" was present in the system. If
 215  * on_dev is NULL then all interfaces are taken into consideration.
 216  */
 217 static inline unsigned int __inet_dev_addr_type(struct net *net,
 218                                                 const struct net_device *dev,
 219                                                 __be32 addr, u32 tb_id)
 220 {
 221         struct flowi4           fl4 = { .daddr = addr };
 222         struct fib_result       res;
 223         unsigned int ret = RTN_BROADCAST;
 224         struct fib_table *table;
 225
 226         if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
 227                 return RTN_BROADCAST;
 228         if (ipv4_is_multicast(addr))
 229                 return RTN_MULTICAST;
 230
 231         rcu_read_lock();
 232
 233         table = fib_get_table(net, tb_id);
 234         if (table) {
 235                 ret = RTN_UNICAST;
 236                 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
 237                         if (!dev || dev == res.fi->fib_dev)
 238                                 ret = res.type;
 239                 }
 240         }
 241
 242         rcu_read_unlock();
 243         return ret;
 244 }
 245
 246 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
 247 {
 248         return __inet_dev_addr_type(net, NULL, addr, tb_id);
 249 }
 250 EXPORT_SYMBOL(inet_addr_type_table);
 251
 252 unsigned int inet_addr_type(struct net *net, __be32 addr)
 253 {
 254         return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
 255 }
 256 EXPORT_SYMBOL(inet_addr_type);
 257
 258 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 259                                 __be32 addr)
 260 {
 261         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 262
 263         return __inet_dev_addr_type(net, dev, addr, rt_table);
 264 }
 265 EXPORT_SYMBOL(inet_dev_addr_type);
 266
 267 /* inet_addr_type with dev == NULL but using the table from a dev
 268  * if one is associated
 269  */
 270 unsigned int inet_addr_type_dev_table(struct net *net,
 271                                       const struct net_device *dev,
 272                                       __be32 addr)
 273 {
 274         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 275
 276         return __inet_dev_addr_type(net, NULL, addr, rt_table);
 277 }
 278 EXPORT_SYMBOL(inet_addr_type_dev_table);
 279
 280 __be32 fib_compute_spec_dst(struct sk_buff *skb)
 281 {
 282         struct net_device *dev = skb->dev;
 283         struct in_device *in_dev;
 284         struct fib_result res;
 285         struct rtable *rt;
 286         struct net *net;
 287         int scope;
 288
 289         rt = skb_rtable(skb);
 290         if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
 291             RTCF_LOCAL)
 292                 return ip_hdr(skb)->daddr;
 293
 294         in_dev = __in_dev_get_rcu(dev);
 295
 296         net = dev_net(dev);
 297
 298         scope = RT_SCOPE_UNIVERSE;
 299         if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 300                 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
 301                 struct flowi4 fl4 = {
 302                         .flowi4_iif = LOOPBACK_IFINDEX,
 303                         .flowi4_oif = l3mdev_master_ifindex_rcu(dev),
 304                         .daddr = ip_hdr(skb)->saddr,
 305                         .flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
 306                         .flowi4_scope = scope,
 307                         .flowi4_mark = vmark ? skb->mark : 0,
 308                 };
 309                 if (!fib_lookup(net, &fl4, &res, 0))
 310                         return FIB_RES_PREFSRC(net, res);
 311         } else {
 312                 scope = RT_SCOPE_LINK;
 313         }
 314
 315         return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 316 }
 317
 318 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
 319 {
 320         bool dev_match = false;
 321 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 322         int ret;
 323
 324         for (ret = 0; ret < fi->fib_nhs; ret++) {
 325                 struct fib_nh *nh = &fi->fib_nh[ret];
 326
 327                 if (nh->nh_dev == dev) {
 328                         dev_match = true;
 329                         break;
 330                 } else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
 331                         dev_match = true;
 332                         break;
 333                 }
 334         }
 335 #else
 336         if (fi->fib_nh[0].nh_dev == dev)
 337                 dev_match = true;
 338 #endif
 339
 340         return dev_match;
 341 }
 342 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
 343
 344 /* Given (packet source, input interface) and optional (dst, oif, tos):
 345  * - (main) check, that source is valid i.e. not broadcast or our local
 346  *   address.
 347  * - figure out what "logical" interface this packet arrived
 348  *   and calculate "specific destination" address.
 349  * - check, that packet arrived from expected physical interface.
 350  * called with rcu_read_lock()
 351  */
 352 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 353                                  u8 tos, int oif, struct net_device *dev,
 354                                  int rpf, struct in_device *idev, u32 *itag)
 355 {
 356         struct net *net = dev_net(dev);
 357         struct flow_keys flkeys;
 358         int ret, no_addr;
 359         struct fib_result res;
 360         struct flowi4 fl4;
 361         bool dev_match;
 362
 363         fl4.flowi4_oif = 0;
 364         fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
 365         if (!fl4.flowi4_iif)
 366                 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
 367         fl4.daddr = src;
 368         fl4.saddr = dst;
 369         fl4.flowi4_tos = tos;
 370         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 371         fl4.flowi4_tun_key.tun_id = 0;
 372         fl4.flowi4_flags = 0;
 373         fl4.flowi4_uid = sock_net_uid(net, NULL);
 374
 375         no_addr = idev->ifa_list == NULL;
 376
 377         fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
 378         if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
 379                 fl4.flowi4_proto = 0;
 380                 fl4.fl4_sport = 0;
 381                 fl4.fl4_dport = 0;
 382         }
 383
 384         if (fib_lookup(net, &fl4, &res, 0))
 385                 goto last_resort;
 386         if (res.type != RTN_UNICAST &&
 387             (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
 388                 goto e_inval;
 389         fib_combine_itag(itag, &res);
 390
 391         dev_match = fib_info_nh_uses_dev(res.fi, dev);
 392         if (dev_match) {
 393                 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 394                 return ret;
 395         }
 396         if (no_addr)
 397                 goto last_resort;
 398         if (rpf == 1)
 399                 goto e_rpf;
 400         fl4.flowi4_oif = dev->ifindex;
 401
 402         ret = 0;
 403         if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
 404                 if (res.type == RTN_UNICAST)
 405                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 406         }
 407         return ret;
 408
 409 last_resort:
 410         if (rpf)
 411                 goto e_rpf;
 412         *itag = 0;
 413         return 0;
 414
 415 e_inval:
 416         return -EINVAL;
 417 e_rpf:
 418         return -EXDEV;
 419 }
 420
 421 /* Ignore rp_filter for packets protected by IPsec. */
 422 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 423                         u8 tos, int oif, struct net_device *dev,
 424                         struct in_device *idev, u32 *itag)
 425 {
 426         int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 427         struct net *net = dev_net(dev);
 428
 429         if (!r && !fib_num_tclassid_users(net) &&
 430             (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
 431                 if (IN_DEV_ACCEPT_LOCAL(idev))
 432                         goto ok;
 433                 /* with custom local routes in place, checking local addresses
 434                  * only will be too optimistic, with custom rules, checking
 435                  * local addresses only can be too strict, e.g. due to vrf
 436                  */
 437                 if (net->ipv4.fib_has_custom_local_routes ||
 438                     fib4_has_custom_rules(net))
 439                         goto full_check;
 440                 if (inet_lookup_ifaddr_rcu(net, src))
 441                         return -EINVAL;
 442
 443 ok:
 444                 *itag = 0;
 445                 return 0;
 446         }
 447
 448 full_check:
 449         return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 450 }
 451
 452 static inline __be32 sk_extract_addr(struct sockaddr *addr)
 453 {
 454         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 455 }
 456
 457 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 458 {
 459         struct nlattr *nla;
 460
 461         nla = (struct nlattr *) ((char *) mx + len);
 462         nla->nla_type = type;
 463         nla->nla_len = nla_attr_size(4);
 464         *(u32 *) nla_data(nla) = value;
 465
 466         return len + nla_total_size(4);
 467 }
 468
 469 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 470                                  struct fib_config *cfg)
 471 {
 472         __be32 addr;
 473         int plen;
 474
 475         memset(cfg, 0, sizeof(*cfg));
 476         cfg->fc_nlinfo.nl_net = net;
 477
 478         if (rt->rt_dst.sa_family != AF_INET)
 479                 return -EAFNOSUPPORT;
 480
 481         /*
 482          * Check mask for validity:
 483          * a) it must be contiguous.
 484          * b) destination must have all host bits clear.
 485          * c) if application forgot to set correct family (AF_INET),
 486          *    reject request unless it is absolutely clear i.e.
 487          *    both family and mask are zero.
 488          */
 489         plen = 32;
 490         addr = sk_extract_addr(&rt->rt_dst);
 491         if (!(rt->rt_flags & RTF_HOST)) {
 492                 __be32 mask = sk_extract_addr(&rt->rt_genmask);
 493
 494                 if (rt->rt_genmask.sa_family != AF_INET) {
 495                         if (mask || rt->rt_genmask.sa_family)
 496                                 return -EAFNOSUPPORT;
 497                 }
 498
 499                 if (bad_mask(mask, addr))
 500                         return -EINVAL;
 501
 502                 plen = inet_mask_len(mask);
 503         }
 504
 505         cfg->fc_dst_len = plen;
 506         cfg->fc_dst = addr;
 507
 508         if (cmd != SIOCDELRT) {
 509                 cfg->fc_nlflags = NLM_F_CREATE;
 510                 cfg->fc_protocol = RTPROT_BOOT;
 511         }
 512
 513         if (rt->rt_metric)
 514                 cfg->fc_priority = rt->rt_metric - 1;
 515
 516         if (rt->rt_flags & RTF_REJECT) {
 517                 cfg->fc_scope = RT_SCOPE_HOST;
 518                 cfg->fc_type = RTN_UNREACHABLE;
 519                 return 0;
 520         }
 521
 522         cfg->fc_scope = RT_SCOPE_NOWHERE;
 523         cfg->fc_type = RTN_UNICAST;
 524
 525         if (rt->rt_dev) {
 526                 char *colon;
 527                 struct net_device *dev;
 528                 char devname[IFNAMSIZ];
 529
 530                 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 531                         return -EFAULT;
 532
 533                 devname[IFNAMSIZ-1] = 0;
 534                 colon = strchr(devname, ':');
 535                 if (colon)
 536                         *colon = 0;
 537                 dev = __dev_get_by_name(net, devname);
 538                 if (!dev)
 539                         return -ENODEV;
 540                 cfg->fc_oif = dev->ifindex;
 541                 cfg->fc_table = l3mdev_fib_table(dev);
 542                 if (colon) {
 543                         struct in_ifaddr *ifa;
 544                         struct in_device *in_dev = __in_dev_get_rtnl(dev);
 545                         if (!in_dev)
 546                                 return -ENODEV;
 547                         *colon = ':';
 548                         for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
 549                                 if (strcmp(ifa->ifa_label, devname) == 0)
 550                                         break;
 551                         if (!ifa)
 552                                 return -ENODEV;
 553                         cfg->fc_prefsrc = ifa->ifa_local;
 554                 }
 555         }
 556
 557         addr = sk_extract_addr(&rt->rt_gateway);
 558         if (rt->rt_gateway.sa_family == AF_INET && addr) {
 559                 unsigned int addr_type;
 560
 561                 cfg->fc_gw = addr;
 562                 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
 563                 if (rt->rt_flags & RTF_GATEWAY &&
 564                     addr_type == RTN_UNICAST)
 565                         cfg->fc_scope = RT_SCOPE_UNIVERSE;
 566         }
 567
 568         if (cmd == SIOCDELRT)
 569                 return 0;
 570
 571         if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
 572                 return -EINVAL;
 573
 574         if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 575                 cfg->fc_scope = RT_SCOPE_LINK;
 576
 577         if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 578                 struct nlattr *mx;
 579                 int len = 0;
 580
 581                 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
 582                 if (!mx)
 583                         return -ENOMEM;
 584
 585                 if (rt->rt_flags & RTF_MTU)
 586                         len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 587
 588                 if (rt->rt_flags & RTF_WINDOW)
 589                         len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 590
 591                 if (rt->rt_flags & RTF_IRTT)
 592                         len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 593
 594                 cfg->fc_mx = mx;
 595                 cfg->fc_mx_len = len;
 596         }
 597
 598         return 0;
 599 }
 600
 601 /*
 602  * Handle IP routing ioctl calls.
 603  * These are used to manipulate the routing tables
 604  */
 605 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
 606 {
 607         struct fib_config cfg;
 608         int err;
 609
 610         switch (cmd) {
 611         case SIOCADDRT:         /* Add a route */
 612         case SIOCDELRT:         /* Delete a route */
 613                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 614                         return -EPERM;
 615
 616                 rtnl_lock();
 617                 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
 618                 if (err == 0) {
 619                         struct fib_table *tb;
 620
 621                         if (cmd == SIOCDELRT) {
 622                                 tb = fib_get_table(net, cfg.fc_table);
 623                                 if (tb)
 624                                         err = fib_table_delete(net, tb, &cfg,
 625                                                                NULL);
 626                                 else
 627                                         err = -ESRCH;
 628                         } else {
 629                                 tb = fib_new_table(net, cfg.fc_table);
 630                                 if (tb)
 631                                         err = fib_table_insert(net, tb,
 632                                                                &cfg, NULL);
 633                                 else
 634                                         err = -ENOBUFS;
 635                         }
 636
 637                         /* allocated by rtentry_to_fib_config() */
 638                         kfree(cfg.fc_mx);
 639                 }
 640                 rtnl_unlock();
 641                 return err;
 642         }
 643         return -EINVAL;
 644 }
 645
 646 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 647         [RTA_DST]               = { .type = NLA_U32 },
 648         [RTA_SRC]               = { .type = NLA_U32 },
 649         [RTA_IIF]               = { .type = NLA_U32 },
 650         [RTA_OIF]               = { .type = NLA_U32 },
 651         [RTA_GATEWAY]           = { .type = NLA_U32 },
 652         [RTA_PRIORITY]          = { .type = NLA_U32 },
 653         [RTA_PREFSRC]           = { .type = NLA_U32 },
 654         [RTA_METRICS]           = { .type = NLA_NESTED },
 655         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 656         [RTA_FLOW]              = { .type = NLA_U32 },
 657         [RTA_ENCAP_TYPE]        = { .type = NLA_U16 },
 658         [RTA_ENCAP]             = { .type = NLA_NESTED },
 659         [RTA_UID]               = { .type = NLA_U32 },
 660         [RTA_MARK]              = { .type = NLA_U32 },
 661         [RTA_TABLE]             = { .type = NLA_U32 },
 662         [RTA_IP_PROTO]          = { .type = NLA_U8 },
 663         [RTA_SPORT]             = { .type = NLA_U16 },
 664         [RTA_DPORT]             = { .type = NLA_U16 },
 665 };
 666
 667 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 668                              struct nlmsghdr *nlh, struct fib_config *cfg,
 669                              struct netlink_ext_ack *extack)
 670 {
 671         struct nlattr *attr;
 672         int err, remaining;
 673         struct rtmsg *rtm;
 674
 675         err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy,
 676                              extack);
 677         if (err < 0)
 678                 goto errout;
 679
 680         memset(cfg, 0, sizeof(*cfg));
 681
 682         rtm = nlmsg_data(nlh);
 683         cfg->fc_dst_len = rtm->rtm_dst_len;
 684         cfg->fc_tos = rtm->rtm_tos;
 685         cfg->fc_table = rtm->rtm_table;
 686         cfg->fc_protocol = rtm->rtm_protocol;
 687         cfg->fc_scope = rtm->rtm_scope;
 688         cfg->fc_type = rtm->rtm_type;
 689         cfg->fc_flags = rtm->rtm_flags;
 690         cfg->fc_nlflags = nlh->nlmsg_flags;
 691
 692         cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 693         cfg->fc_nlinfo.nlh = nlh;
 694         cfg->fc_nlinfo.nl_net = net;
 695
 696         if (cfg->fc_type > RTN_MAX) {
 697                 NL_SET_ERR_MSG(extack, "Invalid route type");
 698                 err = -EINVAL;
 699                 goto errout;
 700         }
 701
 702         nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 703                 switch (nla_type(attr)) {
 704                 case RTA_DST:
 705                         cfg->fc_dst = nla_get_be32(attr);
 706                         break;
 707                 case RTA_OIF:
 708                         cfg->fc_oif = nla_get_u32(attr);
 709                         break;
 710                 case RTA_GATEWAY:
 711                         cfg->fc_gw = nla_get_be32(attr);
 712                         break;
 713                 case RTA_PRIORITY:
 714                         cfg->fc_priority = nla_get_u32(attr);
 715                         break;
 716                 case RTA_PREFSRC:
 717                         cfg->fc_prefsrc = nla_get_be32(attr);
 718                         break;
 719                 case RTA_METRICS:
 720                         cfg->fc_mx = nla_data(attr);
 721                         cfg->fc_mx_len = nla_len(attr);
 722                         break;
 723                 case RTA_MULTIPATH:
 724                         err = lwtunnel_valid_encap_type_attr(nla_data(attr),
 725                                                              nla_len(attr),
 726                                                              extack);
 727                         if (err < 0)
 728                                 goto errout;
 729                         cfg->fc_mp = nla_data(attr);
 730                         cfg->fc_mp_len = nla_len(attr);
 731                         break;
 732                 case RTA_FLOW:
 733                         cfg->fc_flow = nla_get_u32(attr);
 734                         break;
 735                 case RTA_TABLE:
 736                         cfg->fc_table = nla_get_u32(attr);
 737                         break;
 738                 case RTA_ENCAP:
 739                         cfg->fc_encap = attr;
 740                         break;
 741                 case RTA_ENCAP_TYPE:
 742                         cfg->fc_encap_type = nla_get_u16(attr);
 743                         err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
 744                                                         extack);
 745                         if (err < 0)
 746                                 goto errout;
 747                         break;
 748                 }
 749         }
 750
 751         return 0;
 752 errout:
 753         return err;
 754 }
 755
 756 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 757                              struct netlink_ext_ack *extack)
 758 {
 759         struct net *net = sock_net(skb->sk);
 760         struct fib_config cfg;
 761         struct fib_table *tb;
 762         int err;
 763
 764         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 765         if (err < 0)
 766                 goto errout;
 767
 768         tb = fib_get_table(net, cfg.fc_table);
 769         if (!tb) {
 770                 NL_SET_ERR_MSG(extack, "FIB table does not exist");
 771                 err = -ESRCH;
 772                 goto errout;
 773         }
 774
 775         err = fib_table_delete(net, tb, &cfg, extack);
 776 errout:
 777         return err;
 778 }
 779
 780 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 781                              struct netlink_ext_ack *extack)
 782 {
 783         struct net *net = sock_net(skb->sk);
 784         struct fib_config cfg;
 785         struct fib_table *tb;
 786         int err;
 787
 788         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 789         if (err < 0)
 790                 goto errout;
 791
 792         tb = fib_new_table(net, cfg.fc_table);
 793         if (!tb) {
 794                 err = -ENOBUFS;
 795                 goto errout;
 796         }
 797
 798         err = fib_table_insert(net, tb, &cfg, extack);
 799         if (!err && cfg.fc_type == RTN_LOCAL)
 800                 net->ipv4.fib_has_custom_local_routes = true;
 801 errout:
 802         return err;
 803 }
 804
 805 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 806                           struct fib_dump_filter *filter,
 807                           struct netlink_callback *cb)
 808 {
 809         struct netlink_ext_ack *extack = cb->extack;
 810         struct nlattr *tb[RTA_MAX + 1];
 811         struct rtmsg *rtm;
 812         int err, i;
 813
 814         ASSERT_RTNL();
 815
 816         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
 817                 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
 818                 return -EINVAL;
 819         }
 820
 821         rtm = nlmsg_data(nlh);
 822         if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
 823             rtm->rtm_scope) {
 824                 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
 825                 return -EINVAL;
 826         }
 827         if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
 828                 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
 829                 return -EINVAL;
 830         }
 831
 832         filter->flags    = rtm->rtm_flags;
 833         filter->protocol = rtm->rtm_protocol;
 834         filter->rt_type  = rtm->rtm_type;
 835         filter->table_id = rtm->rtm_table;
 836
 837         err = nlmsg_parse_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
 838                                  rtm_ipv4_policy, extack);
 839         if (err < 0)
 840                 return err;
 841
 842         for (i = 0; i <= RTA_MAX; ++i) {
 843                 int ifindex;
 844
 845                 if (!tb[i])
 846                         continue;
 847
 848                 switch (i) {
 849                 case RTA_TABLE:
 850                         filter->table_id = nla_get_u32(tb[i]);
 851                         break;
 852                 case RTA_OIF:
 853                         ifindex = nla_get_u32(tb[i]);
 854                         filter->dev = __dev_get_by_index(net, ifindex);
 855                         if (!filter->dev)
 856                                 return -ENODEV;
 857                         break;
 858                 default:
 859                         NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
 860                         return -EINVAL;
 861                 }
 862         }
 863
 864         if (filter->flags || filter->protocol || filter->rt_type ||
 865             filter->table_id || filter->dev) {
 866                 filter->filter_set = 1;
 867                 cb->answer_flags = NLM_F_DUMP_FILTERED;
 868         }
 869
 870         return 0;
 871 }
 872 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
 873
 874 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 875 {
 876         const struct nlmsghdr *nlh = cb->nlh;
 877         struct net *net = sock_net(skb->sk);
 878         struct fib_dump_filter filter = {};
 879         unsigned int h, s_h;
 880         unsigned int e = 0, s_e;
 881         struct fib_table *tb;
 882         struct hlist_head *head;
 883         int dumped = 0, err;
 884
 885         if (cb->strict_check) {
 886                 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
 887                 if (err < 0)
 888                         return err;
 889         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 890                 struct rtmsg *rtm = nlmsg_data(nlh);
 891
 892                 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
 893         }
 894
 895         /* fib entries are never clones and ipv4 does not use prefix flag */
 896         if (filter.flags & (RTM_F_PREFIX | RTM_F_CLONED))
 897                 return skb->len;
 898
 899         if (filter.table_id) {
 900                 tb = fib_get_table(net, filter.table_id);
 901                 if (!tb) {
 902                         NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
 903                         return -ENOENT;
 904                 }
 905
 906                 err = fib_table_dump(tb, skb, cb, &filter);
 907                 return skb->len ? : err;
 908         }
 909
 910         s_h = cb->args[0];
 911         s_e = cb->args[1];
 912
 913         rcu_read_lock();
 914
 915         for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 916                 e = 0;
 917                 head = &net->ipv4.fib_table_hash[h];
 918                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 919                         if (e < s_e)
 920                                 goto next;
 921                         if (dumped)
 922                                 memset(&cb->args[2], 0, sizeof(cb->args) -
 923                                                  2 * sizeof(cb->args[0]));
 924                         err = fib_table_dump(tb, skb, cb, &filter);
 925                         if (err < 0) {
 926                                 if (likely(skb->len))
 927                                         goto out;
 928
 929                                 goto out_err;
 930                         }
 931                         dumped = 1;
 932 next:
 933                         e++;
 934                 }
 935         }
 936 out:
 937         err = skb->len;
 938 out_err:
 939         rcu_read_unlock();
 940
 941         cb->args[1] = e;
 942         cb->args[0] = h;
 943
 944         return err;
 945 }
 946
 947 /* Prepare and feed intra-kernel routing request.
 948  * Really, it should be netlink message, but :-( netlink
 949  * can be not configured, so that we feed it directly
 950  * to fib engine. It is legal, because all events occur
 951  * only when netlink is already locked.
 952  */
 953 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
 954                       struct in_ifaddr *ifa, u32 rt_priority)
 955 {
 956         struct net *net = dev_net(ifa->ifa_dev->dev);
 957         u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
 958         struct fib_table *tb;
 959         struct fib_config cfg = {
 960                 .fc_protocol = RTPROT_KERNEL,
 961                 .fc_type = type,
 962                 .fc_dst = dst,
 963                 .fc_dst_len = dst_len,
 964                 .fc_priority = rt_priority,
 965                 .fc_prefsrc = ifa->ifa_local,
 966                 .fc_oif = ifa->ifa_dev->dev->ifindex,
 967                 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
 968                 .fc_nlinfo = {
 969                         .nl_net = net,
 970                 },
 971         };
 972
 973         if (!tb_id)
 974                 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
 975
 976         tb = fib_new_table(net, tb_id);
 977         if (!tb)
 978                 return;
 979
 980         cfg.fc_table = tb->tb_id;
 981
 982         if (type != RTN_LOCAL)
 983                 cfg.fc_scope = RT_SCOPE_LINK;
 984         else
 985                 cfg.fc_scope = RT_SCOPE_HOST;
 986
 987         if (cmd == RTM_NEWROUTE)
 988                 fib_table_insert(net, tb, &cfg, NULL);
 989         else
 990                 fib_table_delete(net, tb, &cfg, NULL);
 991 }
 992
 993 void fib_add_ifaddr(struct in_ifaddr *ifa)
 994 {
 995         struct in_device *in_dev = ifa->ifa_dev;
 996         struct net_device *dev = in_dev->dev;
 997         struct in_ifaddr *prim = ifa;
 998         __be32 mask = ifa->ifa_mask;
 999         __be32 addr = ifa->ifa_local;
1000         __be32 prefix = ifa->ifa_address & mask;
1001
1002         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1003                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1004                 if (!prim) {
1005                         pr_warn("%s: bug: prim == NULL\n", __func__);
1006                         return;
1007                 }
1008         }
1009
1010         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1011
1012         if (!(dev->flags & IFF_UP))
1013                 return;
1014
1015         /* Add broadcast address, if it is explicitly assigned. */
1016         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
1017                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1018                           prim, 0);
1019
1020         if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1021             (prefix != addr || ifa->ifa_prefixlen < 32)) {
1022                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1023                         fib_magic(RTM_NEWROUTE,
1024                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1025                                   prefix, ifa->ifa_prefixlen, prim,
1026                                   ifa->ifa_rt_priority);
1027
1028                 /* Add network specific broadcasts, when it takes a sense */
1029                 if (ifa->ifa_prefixlen < 31) {
1030                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32,
1031                                   prim, 0);
1032                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1033                                   32, prim, 0);
1034                 }
1035         }
1036 }
1037
1038 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1039 {
1040         __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1041         struct in_device *in_dev = ifa->ifa_dev;
1042         struct net_device *dev = in_dev->dev;
1043
1044         if (!(dev->flags & IFF_UP) ||
1045             ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1046             ipv4_is_zeronet(prefix) ||
1047             prefix == ifa->ifa_local || ifa->ifa_prefixlen == 32)
1048                 return;
1049
1050         /* add the new */
1051         fib_magic(RTM_NEWROUTE,
1052                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1053                   prefix, ifa->ifa_prefixlen, ifa, new_metric);
1054
1055         /* delete the old */
1056         fib_magic(RTM_DELROUTE,
1057                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1058                   prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1059 }
1060
1061 /* Delete primary or secondary address.
1062  * Optionally, on secondary address promotion consider the addresses
1063  * from subnet iprim as deleted, even if they are in device list.
1064  * In this case the secondary ifa can be in device list.
1065  */
1066 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1067 {
1068         struct in_device *in_dev = ifa->ifa_dev;
1069         struct net_device *dev = in_dev->dev;
1070         struct in_ifaddr *ifa1;
1071         struct in_ifaddr *prim = ifa, *prim1 = NULL;
1072         __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1073         __be32 any = ifa->ifa_address & ifa->ifa_mask;
1074 #define LOCAL_OK        1
1075 #define BRD_OK          2
1076 #define BRD0_OK         4
1077 #define BRD1_OK         8
1078         unsigned int ok = 0;
1079         int subnet = 0;         /* Primary network */
1080         int gone = 1;           /* Address is missing */
1081         int same_prefsrc = 0;   /* Another primary with same IP */
1082
1083         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1084                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1085                 if (!prim) {
1086                         /* if the device has been deleted, we don't perform
1087                          * address promotion
1088                          */
1089                         if (!in_dev->dead)
1090                                 pr_warn("%s: bug: prim == NULL\n", __func__);
1091                         return;
1092                 }
1093                 if (iprim && iprim != prim) {
1094                         pr_warn("%s: bug: iprim != prim\n", __func__);
1095                         return;
1096                 }
1097         } else if (!ipv4_is_zeronet(any) &&
1098                    (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1099                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1100                         fib_magic(RTM_DELROUTE,
1101                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1102                                   any, ifa->ifa_prefixlen, prim, 0);
1103                 subnet = 1;
1104         }
1105
1106         if (in_dev->dead)
1107                 goto no_promotions;
1108
1109         /* Deletion is more complicated than add.
1110          * We should take care of not to delete too much :-)
1111          *
1112          * Scan address list to be sure that addresses are really gone.
1113          */
1114
1115         for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
1116                 if (ifa1 == ifa) {
1117                         /* promotion, keep the IP */
1118                         gone = 0;
1119                         continue;
1120                 }
1121                 /* Ignore IFAs from our subnet */
1122                 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1123                     inet_ifa_match(ifa1->ifa_address, iprim))
1124                         continue;
1125
1126                 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1127                 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1128                         /* Another address from our subnet? */
1129                         if (ifa1->ifa_mask == prim->ifa_mask &&
1130                             inet_ifa_match(ifa1->ifa_address, prim))
1131                                 prim1 = prim;
1132                         else {
1133                                 /* We reached the secondaries, so
1134                                  * same_prefsrc should be determined.
1135                                  */
1136                                 if (!same_prefsrc)
1137                                         continue;
1138                                 /* Search new prim1 if ifa1 is not
1139                                  * using the current prim1
1140                                  */
1141                                 if (!prim1 ||
1142                                     ifa1->ifa_mask != prim1->ifa_mask ||
1143                                     !inet_ifa_match(ifa1->ifa_address, prim1))
1144                                         prim1 = inet_ifa_byprefix(in_dev,
1145                                                         ifa1->ifa_address,
1146                                                         ifa1->ifa_mask);
1147                                 if (!prim1)
1148                                         continue;
1149                                 if (prim1->ifa_local != prim->ifa_local)
1150                                         continue;
1151                         }
1152                 } else {
1153                         if (prim->ifa_local != ifa1->ifa_local)
1154                                 continue;
1155                         prim1 = ifa1;
1156                         if (prim != prim1)
1157                                 same_prefsrc = 1;
1158                 }
1159                 if (ifa->ifa_local == ifa1->ifa_local)
1160                         ok |= LOCAL_OK;
1161                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1162                         ok |= BRD_OK;
1163                 if (brd == ifa1->ifa_broadcast)
1164                         ok |= BRD1_OK;
1165                 if (any == ifa1->ifa_broadcast)
1166                         ok |= BRD0_OK;
1167                 /* primary has network specific broadcasts */
1168                 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1169                         __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1170                         __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1171
1172                         if (!ipv4_is_zeronet(any1)) {
1173                                 if (ifa->ifa_broadcast == brd1 ||
1174                                     ifa->ifa_broadcast == any1)
1175                                         ok |= BRD_OK;
1176                                 if (brd == brd1 || brd == any1)
1177                                         ok |= BRD1_OK;
1178                                 if (any == brd1 || any == any1)
1179                                         ok |= BRD0_OK;
1180                         }
1181                 }
1182         }
1183
1184 no_promotions:
1185         if (!(ok & BRD_OK))
1186                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1187                           prim, 0);
1188         if (subnet && ifa->ifa_prefixlen < 31) {
1189                 if (!(ok & BRD1_OK))
1190                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1191                                   prim, 0);
1192                 if (!(ok & BRD0_OK))
1193                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1194                                   prim, 0);
1195         }
1196         if (!(ok & LOCAL_OK)) {
1197                 unsigned int addr_type;
1198
1199                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1200
1201                 /* Check, that this local address finally disappeared. */
1202                 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1203                                                      ifa->ifa_local);
1204                 if (gone && addr_type != RTN_LOCAL) {
1205                         /* And the last, but not the least thing.
1206                          * We must flush stray FIB entries.
1207                          *
1208                          * First of all, we scan fib_info list searching
1209                          * for stray nexthop entries, then ignite fib_flush.
1210                          */
1211                         if (fib_sync_down_addr(dev, ifa->ifa_local))
1212                                 fib_flush(dev_net(dev));
1213                 }
1214         }
1215 #undef LOCAL_OK
1216 #undef BRD_OK
1217 #undef BRD0_OK
1218 #undef BRD1_OK
1219 }
1220
1221 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1222 {
1223
1224         struct fib_result       res;
1225         struct flowi4           fl4 = {
1226                 .flowi4_mark = frn->fl_mark,
1227                 .daddr = frn->fl_addr,
1228                 .flowi4_tos = frn->fl_tos,
1229                 .flowi4_scope = frn->fl_scope,
1230         };
1231         struct fib_table *tb;
1232
1233         rcu_read_lock();
1234
1235         tb = fib_get_table(net, frn->tb_id_in);
1236
1237         frn->err = -ENOENT;
1238         if (tb) {
1239                 local_bh_disable();
1240
1241                 frn->tb_id = tb->tb_id;
1242                 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1243
1244                 if (!frn->err) {
1245                         frn->prefixlen = res.prefixlen;
1246                         frn->nh_sel = res.nh_sel;
1247                         frn->type = res.type;
1248                         frn->scope = res.scope;
1249                 }
1250                 local_bh_enable();
1251         }
1252
1253         rcu_read_unlock();
1254 }
1255
1256 static void nl_fib_input(struct sk_buff *skb)
1257 {
1258         struct net *net;
1259         struct fib_result_nl *frn;
1260         struct nlmsghdr *nlh;
1261         u32 portid;
1262
1263         net = sock_net(skb->sk);
1264         nlh = nlmsg_hdr(skb);
1265         if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1266             skb->len < nlh->nlmsg_len ||
1267             nlmsg_len(nlh) < sizeof(*frn))
1268                 return;
1269
1270         skb = netlink_skb_clone(skb, GFP_KERNEL);
1271         if (!skb)
1272                 return;
1273         nlh = nlmsg_hdr(skb);
1274
1275         frn = (struct fib_result_nl *) nlmsg_data(nlh);
1276         nl_fib_lookup(net, frn);
1277
1278         portid = NETLINK_CB(skb).portid;      /* netlink portid */
1279         NETLINK_CB(skb).portid = 0;        /* from kernel */
1280         NETLINK_CB(skb).dst_group = 0;  /* unicast */
1281         netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1282 }
1283
1284 static int __net_init nl_fib_lookup_init(struct net *net)
1285 {
1286         struct sock *sk;
1287         struct netlink_kernel_cfg cfg = {
1288                 .input  = nl_fib_input,
1289         };
1290
1291         sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1292         if (!sk)
1293                 return -EAFNOSUPPORT;
1294         net->ipv4.fibnl = sk;
1295         return 0;
1296 }
1297
1298 static void nl_fib_lookup_exit(struct net *net)
1299 {
1300         netlink_kernel_release(net->ipv4.fibnl);
1301         net->ipv4.fibnl = NULL;
1302 }
1303
1304 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1305                            bool force)
1306 {
1307         if (fib_sync_down_dev(dev, event, force))
1308                 fib_flush(dev_net(dev));
1309         else
1310                 rt_cache_flush(dev_net(dev));
1311         arp_ifdown(dev);
1312 }
1313
1314 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1315 {
1316         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1317         struct net_device *dev = ifa->ifa_dev->dev;
1318         struct net *net = dev_net(dev);
1319
1320         switch (event) {
1321         case NETDEV_UP:
1322                 fib_add_ifaddr(ifa);
1323 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1324                 fib_sync_up(dev, RTNH_F_DEAD);
1325 #endif
1326                 atomic_inc(&net->ipv4.dev_addr_genid);
1327                 rt_cache_flush(dev_net(dev));
1328                 break;
1329         case NETDEV_DOWN:
1330                 fib_del_ifaddr(ifa, NULL);
1331                 atomic_inc(&net->ipv4.dev_addr_genid);
1332                 if (!ifa->ifa_dev->ifa_list) {
1333                         /* Last address was deleted from this interface.
1334                          * Disable IP.
1335                          */
1336                         fib_disable_ip(dev, event, true);
1337                 } else {
1338                         rt_cache_flush(dev_net(dev));
1339                 }
1340                 break;
1341         }
1342         return NOTIFY_DONE;
1343 }
1344
1345 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1346 {
1347         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1348         struct netdev_notifier_changeupper_info *upper_info = ptr;
1349         struct netdev_notifier_info_ext *info_ext = ptr;
1350         struct in_device *in_dev;
1351         struct net *net = dev_net(dev);
1352         unsigned int flags;
1353
1354         if (event == NETDEV_UNREGISTER) {
1355                 fib_disable_ip(dev, event, true);
1356                 rt_flush_dev(dev);
1357                 return NOTIFY_DONE;
1358         }
1359
1360         in_dev = __in_dev_get_rtnl(dev);
1361         if (!in_dev)
1362                 return NOTIFY_DONE;
1363
1364         switch (event) {
1365         case NETDEV_UP:
1366                 for_ifa(in_dev) {
1367                         fib_add_ifaddr(ifa);
1368                 } endfor_ifa(in_dev);
1369 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1370                 fib_sync_up(dev, RTNH_F_DEAD);
1371 #endif
1372                 atomic_inc(&net->ipv4.dev_addr_genid);
1373                 rt_cache_flush(net);
1374                 break;
1375         case NETDEV_DOWN:
1376                 fib_disable_ip(dev, event, false);
1377                 break;
1378         case NETDEV_CHANGE:
1379                 flags = dev_get_flags(dev);
1380                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1381                         fib_sync_up(dev, RTNH_F_LINKDOWN);
1382                 else
1383                         fib_sync_down_dev(dev, event, false);
1384                 rt_cache_flush(net);
1385                 break;
1386         case NETDEV_CHANGEMTU:
1387                 fib_sync_mtu(dev, info_ext->ext.mtu);
1388                 rt_cache_flush(net);
1389                 break;
1390         case NETDEV_CHANGEUPPER:
1391                 upper_info = ptr;
1392                 /* flush all routes if dev is linked to or unlinked from
1393                  * an L3 master device (e.g., VRF)
1394                  */
1395                 if (upper_info->upper_dev &&
1396                     netif_is_l3_master(upper_info->upper_dev))
1397                         fib_disable_ip(dev, NETDEV_DOWN, true);
1398                 break;
1399         }
1400         return NOTIFY_DONE;
1401 }
1402
1403 static struct notifier_block fib_inetaddr_notifier = {
1404         .notifier_call = fib_inetaddr_event,
1405 };
1406
1407 static struct notifier_block fib_netdev_notifier = {
1408         .notifier_call = fib_netdev_event,
1409 };
1410
1411 static int __net_init ip_fib_net_init(struct net *net)
1412 {
1413         int err;
1414         size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1415
1416         err = fib4_notifier_init(net);
1417         if (err)
1418                 return err;
1419
1420         /* Avoid false sharing : Use at least a full cache line */
1421         size = max_t(size_t, size, L1_CACHE_BYTES);
1422
1423         net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1424         if (!net->ipv4.fib_table_hash) {
1425                 err = -ENOMEM;
1426                 goto err_table_hash_alloc;
1427         }
1428
1429         err = fib4_rules_init(net);
1430         if (err < 0)
1431                 goto err_rules_init;
1432         return 0;
1433
1434 err_rules_init:
1435         kfree(net->ipv4.fib_table_hash);
1436 err_table_hash_alloc:
1437         fib4_notifier_exit(net);
1438         return err;
1439 }
1440
1441 static void ip_fib_net_exit(struct net *net)
1442 {
1443         int i;
1444
1445         rtnl_lock();
1446 #ifdef CONFIG_IP_MULTIPLE_TABLES
1447         RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1448         RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1449 #endif
1450         /* Destroy the tables in reverse order to guarantee that the
1451          * local table, ID 255, is destroyed before the main table, ID
1452          * 254. This is necessary as the local table may contain
1453          * references to data contained in the main table.
1454          */
1455         for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1456                 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1457                 struct hlist_node *tmp;
1458                 struct fib_table *tb;
1459
1460                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1461                         hlist_del(&tb->tb_hlist);
1462                         fib_table_flush(net, tb);
1463                         fib_free_table(tb);
1464                 }
1465         }
1466
1467 #ifdef CONFIG_IP_MULTIPLE_TABLES
1468         fib4_rules_exit(net);
1469 #endif
1470         rtnl_unlock();
1471         kfree(net->ipv4.fib_table_hash);
1472         fib4_notifier_exit(net);
1473 }
1474
1475 static int __net_init fib_net_init(struct net *net)
1476 {
1477         int error;
1478
1479 #ifdef CONFIG_IP_ROUTE_CLASSID
1480         net->ipv4.fib_num_tclassid_users = 0;
1481 #endif
1482         error = ip_fib_net_init(net);
1483         if (error < 0)
1484                 goto out;
1485         error = nl_fib_lookup_init(net);
1486         if (error < 0)
1487                 goto out_nlfl;
1488         error = fib_proc_init(net);
1489         if (error < 0)
1490                 goto out_proc;
1491 out:
1492         return error;
1493
1494 out_proc:
1495         nl_fib_lookup_exit(net);
1496 out_nlfl:
1497         ip_fib_net_exit(net);
1498         goto out;
1499 }
1500
1501 static void __net_exit fib_net_exit(struct net *net)
1502 {
1503         fib_proc_exit(net);
1504         nl_fib_lookup_exit(net);
1505         ip_fib_net_exit(net);
1506 }
1507
1508 static struct pernet_operations fib_net_ops = {
1509         .init = fib_net_init,
1510         .exit = fib_net_exit,
1511 };
1512
1513 void __init ip_fib_init(void)
1514 {
1515         fib_trie_init();
1516
1517         register_pernet_subsys(&fib_net_ops);
1518
1519         register_netdevice_notifier(&fib_netdev_notifier);
1520         register_inetaddr_notifier(&fib_inetaddr_notifier);
1521
1522         rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1523         rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1524         rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1525 }