net/ipv4/fib_frontend.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              IPv4 Forwarding Information Base: FIB frontend.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/bitops.h>
  15 #include <linux/capability.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/string.h>
  20 #include <linux/socket.h>
  21 #include <linux/sockios.h>
  22 #include <linux/errno.h>
  23 #include <linux/in.h>
  24 #include <linux/inet.h>
  25 #include <linux/inetdevice.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/if_addr.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/cache.h>
  31 #include <linux/init.h>
  32 #include <linux/list.h>
  33 #include <linux/slab.h>
  34
  35 #include <net/ip.h>
  36 #include <net/protocol.h>
  37 #include <net/route.h>
  38 #include <net/tcp.h>
  39 #include <net/sock.h>
  40 #include <net/arp.h>
  41 #include <net/ip_fib.h>
  42 #include <net/nexthop.h>
  43 #include <net/rtnetlink.h>
  44 #include <net/xfrm.h>
  45 #include <net/l3mdev.h>
  46 #include <net/lwtunnel.h>
  47 #include <trace/events/fib.h>
  48
  49 #ifndef CONFIG_IP_MULTIPLE_TABLES
  50
  51 static int __net_init fib4_rules_init(struct net *net)
  52 {
  53         struct fib_table *local_table, *main_table;
  54
  55         main_table  = fib_trie_table(RT_TABLE_MAIN, NULL);
  56         if (!main_table)
  57                 return -ENOMEM;
  58
  59         local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
  60         if (!local_table)
  61                 goto fail;
  62
  63         hlist_add_head_rcu(&local_table->tb_hlist,
  64                                 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
  65         hlist_add_head_rcu(&main_table->tb_hlist,
  66                                 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
  67         return 0;
  68
  69 fail:
  70         fib_free_table(main_table);
  71         return -ENOMEM;
  72 }
  73
  74 static bool fib4_has_custom_rules(struct net *net)
  75 {
  76         return false;
  77 }
  78 #else
  79
  80 struct fib_table *fib_new_table(struct net *net, u32 id)
  81 {
  82         struct fib_table *tb, *alias = NULL;
  83         unsigned int h;
  84
  85         if (id == 0)
  86                 id = RT_TABLE_MAIN;
  87         tb = fib_get_table(net, id);
  88         if (tb)
  89                 return tb;
  90
  91         if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
  92                 alias = fib_new_table(net, RT_TABLE_MAIN);
  93
  94         tb = fib_trie_table(id, alias);
  95         if (!tb)
  96                 return NULL;
  97
  98         switch (id) {
  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 EXPORT_SYMBOL_GPL(fib_new_table);
 114
 115 /* caller must hold either rtnl or rcu read lock */
 116 struct fib_table *fib_get_table(struct net *net, u32 id)
 117 {
 118         struct fib_table *tb;
 119         struct hlist_head *head;
 120         unsigned int h;
 121
 122         if (id == 0)
 123                 id = RT_TABLE_MAIN;
 124         h = id & (FIB_TABLE_HASHSZ - 1);
 125
 126         head = &net->ipv4.fib_table_hash[h];
 127         hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 128                 if (tb->tb_id == id)
 129                         return tb;
 130         }
 131         return NULL;
 132 }
 133
 134 static bool fib4_has_custom_rules(struct net *net)
 135 {
 136         return net->ipv4.fib_has_custom_rules;
 137 }
 138 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 139
 140 static void fib_replace_table(struct net *net, struct fib_table *old,
 141                               struct fib_table *new)
 142 {
 143 #ifdef CONFIG_IP_MULTIPLE_TABLES
 144         switch (new->tb_id) {
 145         case RT_TABLE_MAIN:
 146                 rcu_assign_pointer(net->ipv4.fib_main, new);
 147                 break;
 148         case RT_TABLE_DEFAULT:
 149                 rcu_assign_pointer(net->ipv4.fib_default, new);
 150                 break;
 151         default:
 152                 break;
 153         }
 154
 155 #endif
 156         /* replace the old table in the hlist */
 157         hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
 158 }
 159
 160 int fib_unmerge(struct net *net)
 161 {
 162         struct fib_table *old, *new, *main_table;
 163
 164         /* attempt to fetch local table if it has been allocated */
 165         old = fib_get_table(net, RT_TABLE_LOCAL);
 166         if (!old)
 167                 return 0;
 168
 169         new = fib_trie_unmerge(old);
 170         if (!new)
 171                 return -ENOMEM;
 172
 173         /* table is already unmerged */
 174         if (new == old)
 175                 return 0;
 176
 177         /* replace merged table with clean table */
 178         fib_replace_table(net, old, new);
 179         fib_free_table(old);
 180
 181         /* attempt to fetch main table if it has been allocated */
 182         main_table = fib_get_table(net, RT_TABLE_MAIN);
 183         if (!main_table)
 184                 return 0;
 185
 186         /* flush local entries from main table */
 187         fib_table_flush_external(main_table);
 188
 189         return 0;
 190 }
 191
 192 void fib_flush(struct net *net)
 193 {
 194         int flushed = 0;
 195         unsigned int h;
 196
 197         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 198                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
 199                 struct hlist_node *tmp;
 200                 struct fib_table *tb;
 201
 202                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
 203                         flushed += fib_table_flush(net, tb, false);
 204         }
 205
 206         if (flushed)
 207                 rt_cache_flush(net);
 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                         struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
 235
 236                         if (!dev || dev == nhc->nhc_dev)
 237                                 ret = res.type;
 238                 }
 239         }
 240
 241         rcu_read_unlock();
 242         return ret;
 243 }
 244
 245 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
 246 {
 247         return __inet_dev_addr_type(net, NULL, addr, tb_id);
 248 }
 249 EXPORT_SYMBOL(inet_addr_type_table);
 250
 251 unsigned int inet_addr_type(struct net *net, __be32 addr)
 252 {
 253         return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
 254 }
 255 EXPORT_SYMBOL(inet_addr_type);
 256
 257 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 258                                 __be32 addr)
 259 {
 260         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 261
 262         return __inet_dev_addr_type(net, dev, addr, rt_table);
 263 }
 264 EXPORT_SYMBOL(inet_dev_addr_type);
 265
 266 /* inet_addr_type with dev == NULL but using the table from a dev
 267  * if one is associated
 268  */
 269 unsigned int inet_addr_type_dev_table(struct net *net,
 270                                       const struct net_device *dev,
 271                                       __be32 addr)
 272 {
 273         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 274
 275         return __inet_dev_addr_type(net, NULL, addr, rt_table);
 276 }
 277 EXPORT_SYMBOL(inet_addr_type_dev_table);
 278
 279 __be32 fib_compute_spec_dst(struct sk_buff *skb)
 280 {
 281         struct net_device *dev = skb->dev;
 282         struct in_device *in_dev;
 283         struct fib_result res;
 284         struct rtable *rt;
 285         struct net *net;
 286         int scope;
 287
 288         rt = skb_rtable(skb);
 289         if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
 290             RTCF_LOCAL)
 291                 return ip_hdr(skb)->daddr;
 292
 293         in_dev = __in_dev_get_rcu(dev);
 294
 295         net = dev_net(dev);
 296
 297         scope = RT_SCOPE_UNIVERSE;
 298         if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 299                 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
 300                 struct flowi4 fl4 = {
 301                         .flowi4_iif = LOOPBACK_IFINDEX,
 302                         .flowi4_oif = l3mdev_master_ifindex_rcu(dev),
 303                         .daddr = ip_hdr(skb)->saddr,
 304                         .flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
 305                         .flowi4_scope = scope,
 306                         .flowi4_mark = vmark ? skb->mark : 0,
 307                 };
 308                 if (!fib_lookup(net, &fl4, &res, 0))
 309                         return fib_result_prefsrc(net, &res);
 310         } else {
 311                 scope = RT_SCOPE_LINK;
 312         }
 313
 314         return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 315 }
 316
 317 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
 318 {
 319         bool dev_match = false;
 320 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 321         int ret;
 322
 323         for (ret = 0; ret < fib_info_num_path(fi); ret++) {
 324                 const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
 325
 326                 if (nhc->nhc_dev == dev) {
 327                         dev_match = true;
 328                         break;
 329                 } else if (l3mdev_master_ifindex_rcu(nhc->nhc_dev) == dev->ifindex) {
 330                         dev_match = true;
 331                         break;
 332                 }
 333         }
 334 #else
 335         if (fib_info_nhc(fi, 0)->nhc_dev == dev)
 336                 dev_match = true;
 337 #endif
 338
 339         return dev_match;
 340 }
 341 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
 342
 343 /* Given (packet source, input interface) and optional (dst, oif, tos):
 344  * - (main) check, that source is valid i.e. not broadcast or our local
 345  *   address.
 346  * - figure out what "logical" interface this packet arrived
 347  *   and calculate "specific destination" address.
 348  * - check, that packet arrived from expected physical interface.
 349  * called with rcu_read_lock()
 350  */
 351 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 352                                  u8 tos, int oif, struct net_device *dev,
 353                                  int rpf, struct in_device *idev, u32 *itag)
 354 {
 355         struct net *net = dev_net(dev);
 356         struct flow_keys flkeys;
 357         int ret, no_addr;
 358         struct fib_result res;
 359         struct flowi4 fl4;
 360         bool dev_match;
 361
 362         fl4.flowi4_oif = 0;
 363         fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
 364         if (!fl4.flowi4_iif)
 365                 fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
 366         fl4.daddr = src;
 367         fl4.saddr = dst;
 368         fl4.flowi4_tos = tos;
 369         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 370         fl4.flowi4_tun_key.tun_id = 0;
 371         fl4.flowi4_flags = 0;
 372         fl4.flowi4_uid = sock_net_uid(net, NULL);
 373
 374         no_addr = idev->ifa_list == NULL;
 375
 376         fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
 377         if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
 378                 fl4.flowi4_proto = 0;
 379                 fl4.fl4_sport = 0;
 380                 fl4.fl4_dport = 0;
 381         }
 382
 383         if (fib_lookup(net, &fl4, &res, 0))
 384                 goto last_resort;
 385         if (res.type != RTN_UNICAST &&
 386             (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
 387                 goto e_inval;
 388         fib_combine_itag(itag, &res);
 389
 390         dev_match = fib_info_nh_uses_dev(res.fi, dev);
 391         /* This is not common, loopback packets retain skb_dst so normally they
 392          * would not even hit this slow path.
 393          */
 394         dev_match = dev_match || (res.type == RTN_LOCAL &&
 395                                   dev == net->loopback_dev);
 396         if (dev_match) {
 397                 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
 398                 return ret;
 399         }
 400         if (no_addr)
 401                 goto last_resort;
 402         if (rpf == 1)
 403                 goto e_rpf;
 404         fl4.flowi4_oif = dev->ifindex;
 405
 406         ret = 0;
 407         if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
 408                 if (res.type == RTN_UNICAST)
 409                         ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
 410         }
 411         return ret;
 412
 413 last_resort:
 414         if (rpf)
 415                 goto e_rpf;
 416         *itag = 0;
 417         return 0;
 418
 419 e_inval:
 420         return -EINVAL;
 421 e_rpf:
 422         return -EXDEV;
 423 }
 424
 425 /* Ignore rp_filter for packets protected by IPsec. */
 426 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 427                         u8 tos, int oif, struct net_device *dev,
 428                         struct in_device *idev, u32 *itag)
 429 {
 430         int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 431         struct net *net = dev_net(dev);
 432
 433         if (!r && !fib_num_tclassid_users(net) &&
 434             (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
 435                 if (IN_DEV_ACCEPT_LOCAL(idev))
 436                         goto ok;
 437                 /* with custom local routes in place, checking local addresses
 438                  * only will be too optimistic, with custom rules, checking
 439                  * local addresses only can be too strict, e.g. due to vrf
 440                  */
 441                 if (net->ipv4.fib_has_custom_local_routes ||
 442                     fib4_has_custom_rules(net))
 443                         goto full_check;
 444                 if (inet_lookup_ifaddr_rcu(net, src))
 445                         return -EINVAL;
 446
 447 ok:
 448                 *itag = 0;
 449                 return 0;
 450         }
 451
 452 full_check:
 453         return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 454 }
 455
 456 static inline __be32 sk_extract_addr(struct sockaddr *addr)
 457 {
 458         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 459 }
 460
 461 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 462 {
 463         struct nlattr *nla;
 464
 465         nla = (struct nlattr *) ((char *) mx + len);
 466         nla->nla_type = type;
 467         nla->nla_len = nla_attr_size(4);
 468         *(u32 *) nla_data(nla) = value;
 469
 470         return len + nla_total_size(4);
 471 }
 472
 473 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 474                                  struct fib_config *cfg)
 475 {
 476         __be32 addr;
 477         int plen;
 478
 479         memset(cfg, 0, sizeof(*cfg));
 480         cfg->fc_nlinfo.nl_net = net;
 481
 482         if (rt->rt_dst.sa_family != AF_INET)
 483                 return -EAFNOSUPPORT;
 484
 485         /*
 486          * Check mask for validity:
 487          * a) it must be contiguous.
 488          * b) destination must have all host bits clear.
 489          * c) if application forgot to set correct family (AF_INET),
 490          *    reject request unless it is absolutely clear i.e.
 491          *    both family and mask are zero.
 492          */
 493         plen = 32;
 494         addr = sk_extract_addr(&rt->rt_dst);
 495         if (!(rt->rt_flags & RTF_HOST)) {
 496                 __be32 mask = sk_extract_addr(&rt->rt_genmask);
 497
 498                 if (rt->rt_genmask.sa_family != AF_INET) {
 499                         if (mask || rt->rt_genmask.sa_family)
 500                                 return -EAFNOSUPPORT;
 501                 }
 502
 503                 if (bad_mask(mask, addr))
 504                         return -EINVAL;
 505
 506                 plen = inet_mask_len(mask);
 507         }
 508
 509         cfg->fc_dst_len = plen;
 510         cfg->fc_dst = addr;
 511
 512         if (cmd != SIOCDELRT) {
 513                 cfg->fc_nlflags = NLM_F_CREATE;
 514                 cfg->fc_protocol = RTPROT_BOOT;
 515         }
 516
 517         if (rt->rt_metric)
 518                 cfg->fc_priority = rt->rt_metric - 1;
 519
 520         if (rt->rt_flags & RTF_REJECT) {
 521                 cfg->fc_scope = RT_SCOPE_HOST;
 522                 cfg->fc_type = RTN_UNREACHABLE;
 523                 return 0;
 524         }
 525
 526         cfg->fc_scope = RT_SCOPE_NOWHERE;
 527         cfg->fc_type = RTN_UNICAST;
 528
 529         if (rt->rt_dev) {
 530                 char *colon;
 531                 struct net_device *dev;
 532                 char devname[IFNAMSIZ];
 533
 534                 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 535                         return -EFAULT;
 536
 537                 devname[IFNAMSIZ-1] = 0;
 538                 colon = strchr(devname, ':');
 539                 if (colon)
 540                         *colon = 0;
 541                 dev = __dev_get_by_name(net, devname);
 542                 if (!dev)
 543                         return -ENODEV;
 544                 cfg->fc_oif = dev->ifindex;
 545                 cfg->fc_table = l3mdev_fib_table(dev);
 546                 if (colon) {
 547                         const struct in_ifaddr *ifa;
 548                         struct in_device *in_dev;
 549
 550                         in_dev = __in_dev_get_rtnl(dev);
 551                         if (!in_dev)
 552                                 return -ENODEV;
 553
 554                         *colon = ':';
 555
 556                         rcu_read_lock();
 557                         in_dev_for_each_ifa_rcu(ifa, in_dev) {
 558                                 if (strcmp(ifa->ifa_label, devname) == 0)
 559                                         break;
 560                         }
 561                         rcu_read_unlock();
 562
 563                         if (!ifa)
 564                                 return -ENODEV;
 565                         cfg->fc_prefsrc = ifa->ifa_local;
 566                 }
 567         }
 568
 569         addr = sk_extract_addr(&rt->rt_gateway);
 570         if (rt->rt_gateway.sa_family == AF_INET && addr) {
 571                 unsigned int addr_type;
 572
 573                 cfg->fc_gw4 = addr;
 574                 cfg->fc_gw_family = AF_INET;
 575                 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
 576                 if (rt->rt_flags & RTF_GATEWAY &&
 577                     addr_type == RTN_UNICAST)
 578                         cfg->fc_scope = RT_SCOPE_UNIVERSE;
 579         }
 580
 581         if (cmd == SIOCDELRT)
 582                 return 0;
 583
 584         if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
 585                 return -EINVAL;
 586
 587         if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 588                 cfg->fc_scope = RT_SCOPE_LINK;
 589
 590         if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 591                 struct nlattr *mx;
 592                 int len = 0;
 593
 594                 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
 595                 if (!mx)
 596                         return -ENOMEM;
 597
 598                 if (rt->rt_flags & RTF_MTU)
 599                         len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 600
 601                 if (rt->rt_flags & RTF_WINDOW)
 602                         len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 603
 604                 if (rt->rt_flags & RTF_IRTT)
 605                         len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 606
 607                 cfg->fc_mx = mx;
 608                 cfg->fc_mx_len = len;
 609         }
 610
 611         return 0;
 612 }
 613
 614 /*
 615  * Handle IP routing ioctl calls.
 616  * These are used to manipulate the routing tables
 617  */
 618 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
 619 {
 620         struct fib_config cfg;
 621         int err;
 622
 623         switch (cmd) {
 624         case SIOCADDRT:         /* Add a route */
 625         case SIOCDELRT:         /* Delete a route */
 626                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 627                         return -EPERM;
 628
 629                 rtnl_lock();
 630                 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
 631                 if (err == 0) {
 632                         struct fib_table *tb;
 633
 634                         if (cmd == SIOCDELRT) {
 635                                 tb = fib_get_table(net, cfg.fc_table);
 636                                 if (tb)
 637                                         err = fib_table_delete(net, tb, &cfg,
 638                                                                NULL);
 639                                 else
 640                                         err = -ESRCH;
 641                         } else {
 642                                 tb = fib_new_table(net, cfg.fc_table);
 643                                 if (tb)
 644                                         err = fib_table_insert(net, tb,
 645                                                                &cfg, NULL);
 646                                 else
 647                                         err = -ENOBUFS;
 648                         }
 649
 650                         /* allocated by rtentry_to_fib_config() */
 651                         kfree(cfg.fc_mx);
 652                 }
 653                 rtnl_unlock();
 654                 return err;
 655         }
 656         return -EINVAL;
 657 }
 658
 659 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 660         [RTA_UNSPEC]            = { .strict_start_type = RTA_DPORT + 1 },
 661         [RTA_DST]               = { .type = NLA_U32 },
 662         [RTA_SRC]               = { .type = NLA_U32 },
 663         [RTA_IIF]               = { .type = NLA_U32 },
 664         [RTA_OIF]               = { .type = NLA_U32 },
 665         [RTA_GATEWAY]           = { .type = NLA_U32 },
 666         [RTA_PRIORITY]          = { .type = NLA_U32 },
 667         [RTA_PREFSRC]           = { .type = NLA_U32 },
 668         [RTA_METRICS]           = { .type = NLA_NESTED },
 669         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 670         [RTA_FLOW]              = { .type = NLA_U32 },
 671         [RTA_ENCAP_TYPE]        = { .type = NLA_U16 },
 672         [RTA_ENCAP]             = { .type = NLA_NESTED },
 673         [RTA_UID]               = { .type = NLA_U32 },
 674         [RTA_MARK]              = { .type = NLA_U32 },
 675         [RTA_TABLE]             = { .type = NLA_U32 },
 676         [RTA_IP_PROTO]          = { .type = NLA_U8 },
 677         [RTA_SPORT]             = { .type = NLA_U16 },
 678         [RTA_DPORT]             = { .type = NLA_U16 },
 679         [RTA_NH_ID]             = { .type = NLA_U32 },
 680 };
 681
 682 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
 683                     struct netlink_ext_ack *extack)
 684 {
 685         struct rtvia *via;
 686         int alen;
 687
 688         if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
 689                 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
 690                 return -EINVAL;
 691         }
 692
 693         via = nla_data(nla);
 694         alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
 695
 696         switch (via->rtvia_family) {
 697         case AF_INET:
 698                 if (alen != sizeof(__be32)) {
 699                         NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
 700                         return -EINVAL;
 701                 }
 702                 cfg->fc_gw_family = AF_INET;
 703                 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
 704                 break;
 705         case AF_INET6:
 706 #ifdef CONFIG_IPV6
 707                 if (alen != sizeof(struct in6_addr)) {
 708                         NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
 709                         return -EINVAL;
 710                 }
 711                 cfg->fc_gw_family = AF_INET6;
 712                 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
 713 #else
 714                 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
 715                 return -EINVAL;
 716 #endif
 717                 break;
 718         default:
 719                 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
 720                 return -EINVAL;
 721         }
 722
 723         return 0;
 724 }
 725
 726 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 727                              struct nlmsghdr *nlh, struct fib_config *cfg,
 728                              struct netlink_ext_ack *extack)
 729 {
 730         bool has_gw = false, has_via = false;
 731         struct nlattr *attr;
 732         int err, remaining;
 733         struct rtmsg *rtm;
 734
 735         err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
 736                                         rtm_ipv4_policy, extack);
 737         if (err < 0)
 738                 goto errout;
 739
 740         memset(cfg, 0, sizeof(*cfg));
 741
 742         rtm = nlmsg_data(nlh);
 743         cfg->fc_dst_len = rtm->rtm_dst_len;
 744         cfg->fc_tos = rtm->rtm_tos;
 745         cfg->fc_table = rtm->rtm_table;
 746         cfg->fc_protocol = rtm->rtm_protocol;
 747         cfg->fc_scope = rtm->rtm_scope;
 748         cfg->fc_type = rtm->rtm_type;
 749         cfg->fc_flags = rtm->rtm_flags;
 750         cfg->fc_nlflags = nlh->nlmsg_flags;
 751
 752         cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 753         cfg->fc_nlinfo.nlh = nlh;
 754         cfg->fc_nlinfo.nl_net = net;
 755
 756         if (cfg->fc_type > RTN_MAX) {
 757                 NL_SET_ERR_MSG(extack, "Invalid route type");
 758                 err = -EINVAL;
 759                 goto errout;
 760         }
 761
 762         nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 763                 switch (nla_type(attr)) {
 764                 case RTA_DST:
 765                         cfg->fc_dst = nla_get_be32(attr);
 766                         break;
 767                 case RTA_OIF:
 768                         cfg->fc_oif = nla_get_u32(attr);
 769                         break;
 770                 case RTA_GATEWAY:
 771                         has_gw = true;
 772                         cfg->fc_gw4 = nla_get_be32(attr);
 773                         if (cfg->fc_gw4)
 774                                 cfg->fc_gw_family = AF_INET;
 775                         break;
 776                 case RTA_VIA:
 777                         has_via = true;
 778                         err = fib_gw_from_via(cfg, attr, extack);
 779                         if (err)
 780                                 goto errout;
 781                         break;
 782                 case RTA_PRIORITY:
 783                         cfg->fc_priority = nla_get_u32(attr);
 784                         break;
 785                 case RTA_PREFSRC:
 786                         cfg->fc_prefsrc = nla_get_be32(attr);
 787                         break;
 788                 case RTA_METRICS:
 789                         cfg->fc_mx = nla_data(attr);
 790                         cfg->fc_mx_len = nla_len(attr);
 791                         break;
 792                 case RTA_MULTIPATH:
 793                         err = lwtunnel_valid_encap_type_attr(nla_data(attr),
 794                                                              nla_len(attr),
 795                                                              extack);
 796                         if (err < 0)
 797                                 goto errout;
 798                         cfg->fc_mp = nla_data(attr);
 799                         cfg->fc_mp_len = nla_len(attr);
 800                         break;
 801                 case RTA_FLOW:
 802                         cfg->fc_flow = nla_get_u32(attr);
 803                         break;
 804                 case RTA_TABLE:
 805                         cfg->fc_table = nla_get_u32(attr);
 806                         break;
 807                 case RTA_ENCAP:
 808                         cfg->fc_encap = attr;
 809                         break;
 810                 case RTA_ENCAP_TYPE:
 811                         cfg->fc_encap_type = nla_get_u16(attr);
 812                         err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
 813                                                         extack);
 814                         if (err < 0)
 815                                 goto errout;
 816                         break;
 817                 case RTA_NH_ID:
 818                         cfg->fc_nh_id = nla_get_u32(attr);
 819                         break;
 820                 }
 821         }
 822
 823         if (cfg->fc_nh_id) {
 824                 if (cfg->fc_oif || cfg->fc_gw_family ||
 825                     cfg->fc_encap || cfg->fc_mp) {
 826                         NL_SET_ERR_MSG(extack,
 827                                        "Nexthop specification and nexthop id are mutually exclusive");
 828                         return -EINVAL;
 829                 }
 830         }
 831
 832         if (has_gw && has_via) {
 833                 NL_SET_ERR_MSG(extack,
 834                                "Nexthop configuration can not contain both GATEWAY and VIA");
 835                 goto errout;
 836         }
 837
 838         return 0;
 839 errout:
 840         return err;
 841 }
 842
 843 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 844                              struct netlink_ext_ack *extack)
 845 {
 846         struct net *net = sock_net(skb->sk);
 847         struct fib_config cfg;
 848         struct fib_table *tb;
 849         int err;
 850
 851         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 852         if (err < 0)
 853                 goto errout;
 854
 855         if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
 856                 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
 857                 err = -EINVAL;
 858                 goto errout;
 859         }
 860
 861         tb = fib_get_table(net, cfg.fc_table);
 862         if (!tb) {
 863                 NL_SET_ERR_MSG(extack, "FIB table does not exist");
 864                 err = -ESRCH;
 865                 goto errout;
 866         }
 867
 868         err = fib_table_delete(net, tb, &cfg, extack);
 869 errout:
 870         return err;
 871 }
 872
 873 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 874                              struct netlink_ext_ack *extack)
 875 {
 876         struct net *net = sock_net(skb->sk);
 877         struct fib_config cfg;
 878         struct fib_table *tb;
 879         int err;
 880
 881         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 882         if (err < 0)
 883                 goto errout;
 884
 885         tb = fib_new_table(net, cfg.fc_table);
 886         if (!tb) {
 887                 err = -ENOBUFS;
 888                 goto errout;
 889         }
 890
 891         err = fib_table_insert(net, tb, &cfg, extack);
 892         if (!err && cfg.fc_type == RTN_LOCAL)
 893                 net->ipv4.fib_has_custom_local_routes = true;
 894 errout:
 895         return err;
 896 }
 897
 898 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 899                           struct fib_dump_filter *filter,
 900                           struct netlink_callback *cb)
 901 {
 902         struct netlink_ext_ack *extack = cb->extack;
 903         struct nlattr *tb[RTA_MAX + 1];
 904         struct rtmsg *rtm;
 905         int err, i;
 906
 907         ASSERT_RTNL();
 908
 909         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
 910                 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
 911                 return -EINVAL;
 912         }
 913
 914         rtm = nlmsg_data(nlh);
 915         if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
 916             rtm->rtm_scope) {
 917                 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
 918                 return -EINVAL;
 919         }
 920
 921         if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
 922                 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
 923                 return -EINVAL;
 924         }
 925         if (rtm->rtm_flags & RTM_F_CLONED)
 926                 filter->dump_routes = false;
 927         else
 928                 filter->dump_exceptions = false;
 929
 930         filter->dump_all_families = (rtm->rtm_family == AF_UNSPEC);
 931         filter->flags    = rtm->rtm_flags;
 932         filter->protocol = rtm->rtm_protocol;
 933         filter->rt_type  = rtm->rtm_type;
 934         filter->table_id = rtm->rtm_table;
 935
 936         err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
 937                                             rtm_ipv4_policy, extack);
 938         if (err < 0)
 939                 return err;
 940
 941         for (i = 0; i <= RTA_MAX; ++i) {
 942                 int ifindex;
 943
 944                 if (!tb[i])
 945                         continue;
 946
 947                 switch (i) {
 948                 case RTA_TABLE:
 949                         filter->table_id = nla_get_u32(tb[i]);
 950                         break;
 951                 case RTA_OIF:
 952                         ifindex = nla_get_u32(tb[i]);
 953                         filter->dev = __dev_get_by_index(net, ifindex);
 954                         if (!filter->dev)
 955                                 return -ENODEV;
 956                         break;
 957                 default:
 958                         NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
 959                         return -EINVAL;
 960                 }
 961         }
 962
 963         if (filter->flags || filter->protocol || filter->rt_type ||
 964             filter->table_id || filter->dev) {
 965                 filter->filter_set = 1;
 966                 cb->answer_flags = NLM_F_DUMP_FILTERED;
 967         }
 968
 969         return 0;
 970 }
 971 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
 972
 973 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 974 {
 975         struct fib_dump_filter filter = { .dump_routes = true,
 976                                           .dump_exceptions = true };
 977         const struct nlmsghdr *nlh = cb->nlh;
 978         struct net *net = sock_net(skb->sk);
 979         unsigned int h, s_h;
 980         unsigned int e = 0, s_e;
 981         struct fib_table *tb;
 982         struct hlist_head *head;
 983         int dumped = 0, err;
 984
 985         if (cb->strict_check) {
 986                 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
 987                 if (err < 0)
 988                         return err;
 989         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 990                 struct rtmsg *rtm = nlmsg_data(nlh);
 991
 992                 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
 993         }
 994
 995         /* ipv4 does not use prefix flag */
 996         if (filter.flags & RTM_F_PREFIX)
 997                 return skb->len;
 998
 999         if (filter.table_id) {
1000                 tb = fib_get_table(net, filter.table_id);
1001                 if (!tb) {
1002                         if (filter.dump_all_families)
1003                                 return skb->len;
1004
1005                         NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1006                         return -ENOENT;
1007                 }
1008
1009                 err = fib_table_dump(tb, skb, cb, &filter);
1010                 return skb->len ? : err;
1011         }
1012
1013         s_h = cb->args[0];
1014         s_e = cb->args[1];
1015
1016         rcu_read_lock();
1017
1018         for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1019                 e = 0;
1020                 head = &net->ipv4.fib_table_hash[h];
1021                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1022                         if (e < s_e)
1023                                 goto next;
1024                         if (dumped)
1025                                 memset(&cb->args[2], 0, sizeof(cb->args) -
1026                                                  2 * sizeof(cb->args[0]));
1027                         err = fib_table_dump(tb, skb, cb, &filter);
1028                         if (err < 0) {
1029                                 if (likely(skb->len))
1030                                         goto out;
1031
1032                                 goto out_err;
1033                         }
1034                         dumped = 1;
1035 next:
1036                         e++;
1037                 }
1038         }
1039 out:
1040         err = skb->len;
1041 out_err:
1042         rcu_read_unlock();
1043
1044         cb->args[1] = e;
1045         cb->args[0] = h;
1046
1047         return err;
1048 }
1049
1050 /* Prepare and feed intra-kernel routing request.
1051  * Really, it should be netlink message, but :-( netlink
1052  * can be not configured, so that we feed it directly
1053  * to fib engine. It is legal, because all events occur
1054  * only when netlink is already locked.
1055  */
1056 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1057                       struct in_ifaddr *ifa, u32 rt_priority)
1058 {
1059         struct net *net = dev_net(ifa->ifa_dev->dev);
1060         u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1061         struct fib_table *tb;
1062         struct fib_config cfg = {
1063                 .fc_protocol = RTPROT_KERNEL,
1064                 .fc_type = type,
1065                 .fc_dst = dst,
1066                 .fc_dst_len = dst_len,
1067                 .fc_priority = rt_priority,
1068                 .fc_prefsrc = ifa->ifa_local,
1069                 .fc_oif = ifa->ifa_dev->dev->ifindex,
1070                 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1071                 .fc_nlinfo = {
1072                         .nl_net = net,
1073                 },
1074         };
1075
1076         if (!tb_id)
1077                 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1078
1079         tb = fib_new_table(net, tb_id);
1080         if (!tb)
1081                 return;
1082
1083         cfg.fc_table = tb->tb_id;
1084
1085         if (type != RTN_LOCAL)
1086                 cfg.fc_scope = RT_SCOPE_LINK;
1087         else
1088                 cfg.fc_scope = RT_SCOPE_HOST;
1089
1090         if (cmd == RTM_NEWROUTE)
1091                 fib_table_insert(net, tb, &cfg, NULL);
1092         else
1093                 fib_table_delete(net, tb, &cfg, NULL);
1094 }
1095
1096 void fib_add_ifaddr(struct in_ifaddr *ifa)
1097 {
1098         struct in_device *in_dev = ifa->ifa_dev;
1099         struct net_device *dev = in_dev->dev;
1100         struct in_ifaddr *prim = ifa;
1101         __be32 mask = ifa->ifa_mask;
1102         __be32 addr = ifa->ifa_local;
1103         __be32 prefix = ifa->ifa_address & mask;
1104
1105         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1106                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1107                 if (!prim) {
1108                         pr_warn("%s: bug: prim == NULL\n", __func__);
1109                         return;
1110                 }
1111         }
1112
1113         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1114
1115         if (!(dev->flags & IFF_UP))
1116                 return;
1117
1118         /* Add broadcast address, if it is explicitly assigned. */
1119         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
1120                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1121                           prim, 0);
1122
1123         if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1124             (prefix != addr || ifa->ifa_prefixlen < 32)) {
1125                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1126                         fib_magic(RTM_NEWROUTE,
1127                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1128                                   prefix, ifa->ifa_prefixlen, prim,
1129                                   ifa->ifa_rt_priority);
1130
1131                 /* Add network specific broadcasts, when it takes a sense */
1132                 if (ifa->ifa_prefixlen < 31) {
1133                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32,
1134                                   prim, 0);
1135                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1136                                   32, prim, 0);
1137                 }
1138         }
1139 }
1140
1141 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1142 {
1143         __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1144         struct in_device *in_dev = ifa->ifa_dev;
1145         struct net_device *dev = in_dev->dev;
1146
1147         if (!(dev->flags & IFF_UP) ||
1148             ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1149             ipv4_is_zeronet(prefix) ||
1150             prefix == ifa->ifa_local || ifa->ifa_prefixlen == 32)
1151                 return;
1152
1153         /* add the new */
1154         fib_magic(RTM_NEWROUTE,
1155                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1156                   prefix, ifa->ifa_prefixlen, ifa, new_metric);
1157
1158         /* delete the old */
1159         fib_magic(RTM_DELROUTE,
1160                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1161                   prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1162 }
1163
1164 /* Delete primary or secondary address.
1165  * Optionally, on secondary address promotion consider the addresses
1166  * from subnet iprim as deleted, even if they are in device list.
1167  * In this case the secondary ifa can be in device list.
1168  */
1169 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1170 {
1171         struct in_device *in_dev = ifa->ifa_dev;
1172         struct net_device *dev = in_dev->dev;
1173         struct in_ifaddr *ifa1;
1174         struct in_ifaddr *prim = ifa, *prim1 = NULL;
1175         __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1176         __be32 any = ifa->ifa_address & ifa->ifa_mask;
1177 #define LOCAL_OK        1
1178 #define BRD_OK          2
1179 #define BRD0_OK         4
1180 #define BRD1_OK         8
1181         unsigned int ok = 0;
1182         int subnet = 0;         /* Primary network */
1183         int gone = 1;           /* Address is missing */
1184         int same_prefsrc = 0;   /* Another primary with same IP */
1185
1186         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1187                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1188                 if (!prim) {
1189                         /* if the device has been deleted, we don't perform
1190                          * address promotion
1191                          */
1192                         if (!in_dev->dead)
1193                                 pr_warn("%s: bug: prim == NULL\n", __func__);
1194                         return;
1195                 }
1196                 if (iprim && iprim != prim) {
1197                         pr_warn("%s: bug: iprim != prim\n", __func__);
1198                         return;
1199                 }
1200         } else if (!ipv4_is_zeronet(any) &&
1201                    (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1202                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1203                         fib_magic(RTM_DELROUTE,
1204                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1205                                   any, ifa->ifa_prefixlen, prim, 0);
1206                 subnet = 1;
1207         }
1208
1209         if (in_dev->dead)
1210                 goto no_promotions;
1211
1212         /* Deletion is more complicated than add.
1213          * We should take care of not to delete too much :-)
1214          *
1215          * Scan address list to be sure that addresses are really gone.
1216          */
1217         rcu_read_lock();
1218         in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1219                 if (ifa1 == ifa) {
1220                         /* promotion, keep the IP */
1221                         gone = 0;
1222                         continue;
1223                 }
1224                 /* Ignore IFAs from our subnet */
1225                 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1226                     inet_ifa_match(ifa1->ifa_address, iprim))
1227                         continue;
1228
1229                 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1230                 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1231                         /* Another address from our subnet? */
1232                         if (ifa1->ifa_mask == prim->ifa_mask &&
1233                             inet_ifa_match(ifa1->ifa_address, prim))
1234                                 prim1 = prim;
1235                         else {
1236                                 /* We reached the secondaries, so
1237                                  * same_prefsrc should be determined.
1238                                  */
1239                                 if (!same_prefsrc)
1240                                         continue;
1241                                 /* Search new prim1 if ifa1 is not
1242                                  * using the current prim1
1243                                  */
1244                                 if (!prim1 ||
1245                                     ifa1->ifa_mask != prim1->ifa_mask ||
1246                                     !inet_ifa_match(ifa1->ifa_address, prim1))
1247                                         prim1 = inet_ifa_byprefix(in_dev,
1248                                                         ifa1->ifa_address,
1249                                                         ifa1->ifa_mask);
1250                                 if (!prim1)
1251                                         continue;
1252                                 if (prim1->ifa_local != prim->ifa_local)
1253                                         continue;
1254                         }
1255                 } else {
1256                         if (prim->ifa_local != ifa1->ifa_local)
1257                                 continue;
1258                         prim1 = ifa1;
1259                         if (prim != prim1)
1260                                 same_prefsrc = 1;
1261                 }
1262                 if (ifa->ifa_local == ifa1->ifa_local)
1263                         ok |= LOCAL_OK;
1264                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1265                         ok |= BRD_OK;
1266                 if (brd == ifa1->ifa_broadcast)
1267                         ok |= BRD1_OK;
1268                 if (any == ifa1->ifa_broadcast)
1269                         ok |= BRD0_OK;
1270                 /* primary has network specific broadcasts */
1271                 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1272                         __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1273                         __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1274
1275                         if (!ipv4_is_zeronet(any1)) {
1276                                 if (ifa->ifa_broadcast == brd1 ||
1277                                     ifa->ifa_broadcast == any1)
1278                                         ok |= BRD_OK;
1279                                 if (brd == brd1 || brd == any1)
1280                                         ok |= BRD1_OK;
1281                                 if (any == brd1 || any == any1)
1282                                         ok |= BRD0_OK;
1283                         }
1284                 }
1285         }
1286         rcu_read_unlock();
1287
1288 no_promotions:
1289         if (!(ok & BRD_OK))
1290                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1291                           prim, 0);
1292         if (subnet && ifa->ifa_prefixlen < 31) {
1293                 if (!(ok & BRD1_OK))
1294                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1295                                   prim, 0);
1296                 if (!(ok & BRD0_OK))
1297                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1298                                   prim, 0);
1299         }
1300         if (!(ok & LOCAL_OK)) {
1301                 unsigned int addr_type;
1302
1303                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1304
1305                 /* Check, that this local address finally disappeared. */
1306                 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1307                                                      ifa->ifa_local);
1308                 if (gone && addr_type != RTN_LOCAL) {
1309                         /* And the last, but not the least thing.
1310                          * We must flush stray FIB entries.
1311                          *
1312                          * First of all, we scan fib_info list searching
1313                          * for stray nexthop entries, then ignite fib_flush.
1314                          */
1315                         if (fib_sync_down_addr(dev, ifa->ifa_local))
1316                                 fib_flush(dev_net(dev));
1317                 }
1318         }
1319 #undef LOCAL_OK
1320 #undef BRD_OK
1321 #undef BRD0_OK
1322 #undef BRD1_OK
1323 }
1324
1325 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1326 {
1327
1328         struct fib_result       res;
1329         struct flowi4           fl4 = {
1330                 .flowi4_mark = frn->fl_mark,
1331                 .daddr = frn->fl_addr,
1332                 .flowi4_tos = frn->fl_tos,
1333                 .flowi4_scope = frn->fl_scope,
1334         };
1335         struct fib_table *tb;
1336
1337         rcu_read_lock();
1338
1339         tb = fib_get_table(net, frn->tb_id_in);
1340
1341         frn->err = -ENOENT;
1342         if (tb) {
1343                 local_bh_disable();
1344
1345                 frn->tb_id = tb->tb_id;
1346                 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1347
1348                 if (!frn->err) {
1349                         frn->prefixlen = res.prefixlen;
1350                         frn->nh_sel = res.nh_sel;
1351                         frn->type = res.type;
1352                         frn->scope = res.scope;
1353                 }
1354                 local_bh_enable();
1355         }
1356
1357         rcu_read_unlock();
1358 }
1359
1360 static void nl_fib_input(struct sk_buff *skb)
1361 {
1362         struct net *net;
1363         struct fib_result_nl *frn;
1364         struct nlmsghdr *nlh;
1365         u32 portid;
1366
1367         net = sock_net(skb->sk);
1368         nlh = nlmsg_hdr(skb);
1369         if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1370             skb->len < nlh->nlmsg_len ||
1371             nlmsg_len(nlh) < sizeof(*frn))
1372                 return;
1373
1374         skb = netlink_skb_clone(skb, GFP_KERNEL);
1375         if (!skb)
1376                 return;
1377         nlh = nlmsg_hdr(skb);
1378
1379         frn = (struct fib_result_nl *) nlmsg_data(nlh);
1380         nl_fib_lookup(net, frn);
1381
1382         portid = NETLINK_CB(skb).portid;      /* netlink portid */
1383         NETLINK_CB(skb).portid = 0;        /* from kernel */
1384         NETLINK_CB(skb).dst_group = 0;  /* unicast */
1385         netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1386 }
1387
1388 static int __net_init nl_fib_lookup_init(struct net *net)
1389 {
1390         struct sock *sk;
1391         struct netlink_kernel_cfg cfg = {
1392                 .input  = nl_fib_input,
1393         };
1394
1395         sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1396         if (!sk)
1397                 return -EAFNOSUPPORT;
1398         net->ipv4.fibnl = sk;
1399         return 0;
1400 }
1401
1402 static void nl_fib_lookup_exit(struct net *net)
1403 {
1404         netlink_kernel_release(net->ipv4.fibnl);
1405         net->ipv4.fibnl = NULL;
1406 }
1407
1408 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1409                            bool force)
1410 {
1411         if (fib_sync_down_dev(dev, event, force))
1412                 fib_flush(dev_net(dev));
1413         else
1414                 rt_cache_flush(dev_net(dev));
1415         arp_ifdown(dev);
1416 }
1417
1418 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1419 {
1420         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1421         struct net_device *dev = ifa->ifa_dev->dev;
1422         struct net *net = dev_net(dev);
1423
1424         switch (event) {
1425         case NETDEV_UP:
1426                 fib_add_ifaddr(ifa);
1427 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1428                 fib_sync_up(dev, RTNH_F_DEAD);
1429 #endif
1430                 atomic_inc(&net->ipv4.dev_addr_genid);
1431                 rt_cache_flush(dev_net(dev));
1432                 break;
1433         case NETDEV_DOWN:
1434                 fib_del_ifaddr(ifa, NULL);
1435                 atomic_inc(&net->ipv4.dev_addr_genid);
1436                 if (!ifa->ifa_dev->ifa_list) {
1437                         /* Last address was deleted from this interface.
1438                          * Disable IP.
1439                          */
1440                         fib_disable_ip(dev, event, true);
1441                 } else {
1442                         rt_cache_flush(dev_net(dev));
1443                 }
1444                 break;
1445         }
1446         return NOTIFY_DONE;
1447 }
1448
1449 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1450 {
1451         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1452         struct netdev_notifier_changeupper_info *upper_info = ptr;
1453         struct netdev_notifier_info_ext *info_ext = ptr;
1454         struct in_device *in_dev;
1455         struct net *net = dev_net(dev);
1456         struct in_ifaddr *ifa;
1457         unsigned int flags;
1458
1459         if (event == NETDEV_UNREGISTER) {
1460                 fib_disable_ip(dev, event, true);
1461                 rt_flush_dev(dev);
1462                 return NOTIFY_DONE;
1463         }
1464
1465         in_dev = __in_dev_get_rtnl(dev);
1466         if (!in_dev)
1467                 return NOTIFY_DONE;
1468
1469         switch (event) {
1470         case NETDEV_UP:
1471                 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1472                         fib_add_ifaddr(ifa);
1473                 }
1474 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1475                 fib_sync_up(dev, RTNH_F_DEAD);
1476 #endif
1477                 atomic_inc(&net->ipv4.dev_addr_genid);
1478                 rt_cache_flush(net);
1479                 break;
1480         case NETDEV_DOWN:
1481                 fib_disable_ip(dev, event, false);
1482                 break;
1483         case NETDEV_CHANGE:
1484                 flags = dev_get_flags(dev);
1485                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1486                         fib_sync_up(dev, RTNH_F_LINKDOWN);
1487                 else
1488                         fib_sync_down_dev(dev, event, false);
1489                 rt_cache_flush(net);
1490                 break;
1491         case NETDEV_CHANGEMTU:
1492                 fib_sync_mtu(dev, info_ext->ext.mtu);
1493                 rt_cache_flush(net);
1494                 break;
1495         case NETDEV_CHANGEUPPER:
1496                 upper_info = ptr;
1497                 /* flush all routes if dev is linked to or unlinked from
1498                  * an L3 master device (e.g., VRF)
1499                  */
1500                 if (upper_info->upper_dev &&
1501                     netif_is_l3_master(upper_info->upper_dev))
1502                         fib_disable_ip(dev, NETDEV_DOWN, true);
1503                 break;
1504         }
1505         return NOTIFY_DONE;
1506 }
1507
1508 static struct notifier_block fib_inetaddr_notifier = {
1509         .notifier_call = fib_inetaddr_event,
1510 };
1511
1512 static struct notifier_block fib_netdev_notifier = {
1513         .notifier_call = fib_netdev_event,
1514 };
1515
1516 static int __net_init ip_fib_net_init(struct net *net)
1517 {
1518         int err;
1519         size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1520
1521         err = fib4_notifier_init(net);
1522         if (err)
1523                 return err;
1524
1525         /* Avoid false sharing : Use at least a full cache line */
1526         size = max_t(size_t, size, L1_CACHE_BYTES);
1527
1528         net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1529         if (!net->ipv4.fib_table_hash) {
1530                 err = -ENOMEM;
1531                 goto err_table_hash_alloc;
1532         }
1533
1534         err = fib4_rules_init(net);
1535         if (err < 0)
1536                 goto err_rules_init;
1537         return 0;
1538
1539 err_rules_init:
1540         kfree(net->ipv4.fib_table_hash);
1541 err_table_hash_alloc:
1542         fib4_notifier_exit(net);
1543         return err;
1544 }
1545
1546 static void ip_fib_net_exit(struct net *net)
1547 {
1548         int i;
1549
1550         rtnl_lock();
1551 #ifdef CONFIG_IP_MULTIPLE_TABLES
1552         RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1553         RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1554 #endif
1555         /* Destroy the tables in reverse order to guarantee that the
1556          * local table, ID 255, is destroyed before the main table, ID
1557          * 254. This is necessary as the local table may contain
1558          * references to data contained in the main table.
1559          */
1560         for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1561                 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1562                 struct hlist_node *tmp;
1563                 struct fib_table *tb;
1564
1565                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1566                         hlist_del(&tb->tb_hlist);
1567                         fib_table_flush(net, tb, true);
1568                         fib_free_table(tb);
1569                 }
1570         }
1571
1572 #ifdef CONFIG_IP_MULTIPLE_TABLES
1573         fib4_rules_exit(net);
1574 #endif
1575         rtnl_unlock();
1576         kfree(net->ipv4.fib_table_hash);
1577         fib4_notifier_exit(net);
1578 }
1579
1580 static int __net_init fib_net_init(struct net *net)
1581 {
1582         int error;
1583
1584 #ifdef CONFIG_IP_ROUTE_CLASSID
1585         net->ipv4.fib_num_tclassid_users = 0;
1586 #endif
1587         error = ip_fib_net_init(net);
1588         if (error < 0)
1589                 goto out;
1590         error = nl_fib_lookup_init(net);
1591         if (error < 0)
1592                 goto out_nlfl;
1593         error = fib_proc_init(net);
1594         if (error < 0)
1595                 goto out_proc;
1596 out:
1597         return error;
1598
1599 out_proc:
1600         nl_fib_lookup_exit(net);
1601 out_nlfl:
1602         ip_fib_net_exit(net);
1603         goto out;
1604 }
1605
1606 static void __net_exit fib_net_exit(struct net *net)
1607 {
1608         fib_proc_exit(net);
1609         nl_fib_lookup_exit(net);
1610         ip_fib_net_exit(net);
1611 }
1612
1613 static struct pernet_operations fib_net_ops = {
1614         .init = fib_net_init,
1615         .exit = fib_net_exit,
1616 };
1617
1618 void __init ip_fib_init(void)
1619 {
1620         fib_trie_init();
1621
1622         register_pernet_subsys(&fib_net_ops);
1623
1624         register_netdevice_notifier(&fib_netdev_notifier);
1625         register_inetaddr_notifier(&fib_inetaddr_notifier);
1626
1627         rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1628         rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1629         rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1630 }