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/inet_dscp.h>
  36 #include <net/ip.h>
  37 #include <net/protocol.h>
  38 #include <net/route.h>
  39 #include <net/tcp.h>
  40 #include <net/sock.h>
  41 #include <net/arp.h>
  42 #include <net/ip_fib.h>
  43 #include <net/nexthop.h>
  44 #include <net/rtnetlink.h>
  45 #include <net/xfrm.h>
  46 #include <net/l3mdev.h>
  47 #include <net/lwtunnel.h>
  48 #include <trace/events/fib.h>
  49
  50 #ifndef CONFIG_IP_MULTIPLE_TABLES
  51
  52 static int __net_init fib4_rules_init(struct net *net)
  53 {
  54         struct fib_table *local_table, *main_table;
  55
  56         main_table  = fib_trie_table(RT_TABLE_MAIN, NULL);
  57         if (!main_table)
  58                 return -ENOMEM;
  59
  60         local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
  61         if (!local_table)
  62                 goto fail;
  63
  64         hlist_add_head_rcu(&local_table->tb_hlist,
  65                                 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
  66         hlist_add_head_rcu(&main_table->tb_hlist,
  67                                 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
  68         return 0;
  69
  70 fail:
  71         fib_free_table(main_table);
  72         return -ENOMEM;
  73 }
  74 #else
  75
  76 struct fib_table *fib_new_table(struct net *net, u32 id)
  77 {
  78         struct fib_table *tb, *alias = NULL;
  79         unsigned int h;
  80
  81         if (id == 0)
  82                 id = RT_TABLE_MAIN;
  83         tb = fib_get_table(net, id);
  84         if (tb)
  85                 return tb;
  86
  87         if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
  88                 alias = fib_new_table(net, RT_TABLE_MAIN);
  89
  90         tb = fib_trie_table(id, alias);
  91         if (!tb)
  92                 return NULL;
  93
  94         switch (id) {
  95         case RT_TABLE_MAIN:
  96                 rcu_assign_pointer(net->ipv4.fib_main, tb);
  97                 break;
  98         case RT_TABLE_DEFAULT:
  99                 rcu_assign_pointer(net->ipv4.fib_default, tb);
 100                 break;
 101         default:
 102                 break;
 103         }
 104
 105         h = id & (FIB_TABLE_HASHSZ - 1);
 106         hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
 107         return tb;
 108 }
 109 EXPORT_SYMBOL_GPL(fib_new_table);
 110
 111 /* caller must hold either rtnl or rcu read lock */
 112 struct fib_table *fib_get_table(struct net *net, u32 id)
 113 {
 114         struct fib_table *tb;
 115         struct hlist_head *head;
 116         unsigned int h;
 117
 118         if (id == 0)
 119                 id = RT_TABLE_MAIN;
 120         h = id & (FIB_TABLE_HASHSZ - 1);
 121
 122         head = &net->ipv4.fib_table_hash[h];
 123         hlist_for_each_entry_rcu(tb, head, tb_hlist,
 124                                  lockdep_rtnl_is_held()) {
 125                 if (tb->tb_id == id)
 126                         return tb;
 127         }
 128         return NULL;
 129 }
 130 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 131
 132 static void fib_replace_table(struct net *net, struct fib_table *old,
 133                               struct fib_table *new)
 134 {
 135 #ifdef CONFIG_IP_MULTIPLE_TABLES
 136         switch (new->tb_id) {
 137         case RT_TABLE_MAIN:
 138                 rcu_assign_pointer(net->ipv4.fib_main, new);
 139                 break;
 140         case RT_TABLE_DEFAULT:
 141                 rcu_assign_pointer(net->ipv4.fib_default, new);
 142                 break;
 143         default:
 144                 break;
 145         }
 146
 147 #endif
 148         /* replace the old table in the hlist */
 149         hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
 150 }
 151
 152 int fib_unmerge(struct net *net)
 153 {
 154         struct fib_table *old, *new, *main_table;
 155
 156         /* attempt to fetch local table if it has been allocated */
 157         old = fib_get_table(net, RT_TABLE_LOCAL);
 158         if (!old)
 159                 return 0;
 160
 161         new = fib_trie_unmerge(old);
 162         if (!new)
 163                 return -ENOMEM;
 164
 165         /* table is already unmerged */
 166         if (new == old)
 167                 return 0;
 168
 169         /* replace merged table with clean table */
 170         fib_replace_table(net, old, new);
 171         fib_free_table(old);
 172
 173         /* attempt to fetch main table if it has been allocated */
 174         main_table = fib_get_table(net, RT_TABLE_MAIN);
 175         if (!main_table)
 176                 return 0;
 177
 178         /* flush local entries from main table */
 179         fib_table_flush_external(main_table);
 180
 181         return 0;
 182 }
 183
 184 void fib_flush(struct net *net)
 185 {
 186         int flushed = 0;
 187         unsigned int h;
 188
 189         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 190                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
 191                 struct hlist_node *tmp;
 192                 struct fib_table *tb;
 193
 194                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
 195                         flushed += fib_table_flush(net, tb, false);
 196         }
 197
 198         if (flushed)
 199                 rt_cache_flush(net);
 200 }
 201
 202 /*
 203  * Find address type as if only "dev" was present in the system. If
 204  * on_dev is NULL then all interfaces are taken into consideration.
 205  */
 206 static inline unsigned int __inet_dev_addr_type(struct net *net,
 207                                                 const struct net_device *dev,
 208                                                 __be32 addr, u32 tb_id)
 209 {
 210         struct flowi4           fl4 = { .daddr = addr };
 211         struct fib_result       res;
 212         unsigned int ret = RTN_BROADCAST;
 213         struct fib_table *table;
 214
 215         if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
 216                 return RTN_BROADCAST;
 217         if (ipv4_is_multicast(addr))
 218                 return RTN_MULTICAST;
 219
 220         rcu_read_lock();
 221
 222         table = fib_get_table(net, tb_id);
 223         if (table) {
 224                 ret = RTN_UNICAST;
 225                 if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
 226                         struct fib_nh_common *nhc = fib_info_nhc(res.fi, 0);
 227
 228                         if (!dev || dev == nhc->nhc_dev)
 229                                 ret = res.type;
 230                 }
 231         }
 232
 233         rcu_read_unlock();
 234         return ret;
 235 }
 236
 237 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
 238 {
 239         return __inet_dev_addr_type(net, NULL, addr, tb_id);
 240 }
 241 EXPORT_SYMBOL(inet_addr_type_table);
 242
 243 unsigned int inet_addr_type(struct net *net, __be32 addr)
 244 {
 245         return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
 246 }
 247 EXPORT_SYMBOL(inet_addr_type);
 248
 249 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 250                                 __be32 addr)
 251 {
 252         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 253
 254         return __inet_dev_addr_type(net, dev, addr, rt_table);
 255 }
 256 EXPORT_SYMBOL(inet_dev_addr_type);
 257
 258 /* inet_addr_type with dev == NULL but using the table from a dev
 259  * if one is associated
 260  */
 261 unsigned int inet_addr_type_dev_table(struct net *net,
 262                                       const struct net_device *dev,
 263                                       __be32 addr)
 264 {
 265         u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
 266
 267         return __inet_dev_addr_type(net, NULL, addr, rt_table);
 268 }
 269 EXPORT_SYMBOL(inet_addr_type_dev_table);
 270
 271 __be32 fib_compute_spec_dst(struct sk_buff *skb)
 272 {
 273         struct net_device *dev = skb->dev;
 274         struct in_device *in_dev;
 275         struct fib_result res;
 276         struct rtable *rt;
 277         struct net *net;
 278         int scope;
 279
 280         rt = skb_rtable(skb);
 281         if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
 282             RTCF_LOCAL)
 283                 return ip_hdr(skb)->daddr;
 284
 285         in_dev = __in_dev_get_rcu(dev);
 286
 287         net = dev_net(dev);
 288
 289         scope = RT_SCOPE_UNIVERSE;
 290         if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 291                 bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
 292                 struct flowi4 fl4 = {
 293                         .flowi4_iif = LOOPBACK_IFINDEX,
 294                         .flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev),
 295                         .daddr = ip_hdr(skb)->saddr,
 296                         .flowi4_tos = ip_hdr(skb)->tos & IPTOS_RT_MASK,
 297                         .flowi4_scope = scope,
 298                         .flowi4_mark = vmark ? skb->mark : 0,
 299                 };
 300                 if (!fib_lookup(net, &fl4, &res, 0))
 301                         return fib_result_prefsrc(net, &res);
 302         } else {
 303                 scope = RT_SCOPE_LINK;
 304         }
 305
 306         return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 307 }
 308
 309 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev)
 310 {
 311         bool dev_match = false;
 312 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 313         if (unlikely(fi->nh)) {
 314                 dev_match = nexthop_uses_dev(fi->nh, dev);
 315         } else {
 316                 int ret;
 317
 318                 for (ret = 0; ret < fib_info_num_path(fi); ret++) {
 319                         const struct fib_nh_common *nhc = fib_info_nhc(fi, ret);
 320
 321                         if (nhc_l3mdev_matches_dev(nhc, dev)) {
 322                                 dev_match = true;
 323                                 break;
 324                         }
 325                 }
 326         }
 327 #else
 328         if (fib_info_nhc(fi, 0)->nhc_dev == dev)
 329                 dev_match = true;
 330 #endif
 331
 332         return dev_match;
 333 }
 334 EXPORT_SYMBOL_GPL(fib_info_nh_uses_dev);
 335
 336 /* Given (packet source, input interface) and optional (dst, oif, tos):
 337  * - (main) check, that source is valid i.e. not broadcast or our local
 338  *   address.
 339  * - figure out what "logical" interface this packet arrived
 340  *   and calculate "specific destination" address.
 341  * - check, that packet arrived from expected physical interface.
 342  * called with rcu_read_lock()
 343  */
 344 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 345                                  u8 tos, int oif, struct net_device *dev,
 346                                  int rpf, struct in_device *idev, u32 *itag)
 347 {
 348         struct net *net = dev_net(dev);
 349         struct flow_keys flkeys;
 350         int ret, no_addr;
 351         struct fib_result res;
 352         struct flowi4 fl4;
 353         bool dev_match;
 354
 355         fl4.flowi4_oif = 0;
 356         fl4.flowi4_l3mdev = l3mdev_master_ifindex_rcu(dev);
 357         fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
 358         fl4.daddr = src;
 359         fl4.saddr = dst;
 360         fl4.flowi4_tos = tos;
 361         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 362         fl4.flowi4_tun_key.tun_id = 0;
 363         fl4.flowi4_flags = 0;
 364         fl4.flowi4_uid = sock_net_uid(net, NULL);
 365         fl4.flowi4_multipath_hash = 0;
 366
 367         no_addr = idev->ifa_list == NULL;
 368
 369         fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
 370         if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
 371                 fl4.flowi4_proto = 0;
 372                 fl4.fl4_sport = 0;
 373                 fl4.fl4_dport = 0;
 374         } else {
 375                 swap(fl4.fl4_sport, fl4.fl4_dport);
 376         }
 377
 378         if (fib_lookup(net, &fl4, &res, 0))
 379                 goto last_resort;
 380         if (res.type != RTN_UNICAST &&
 381             (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
 382                 goto e_inval;
 383         fib_combine_itag(itag, &res);
 384
 385         dev_match = fib_info_nh_uses_dev(res.fi, dev);
 386         /* This is not common, loopback packets retain skb_dst so normally they
 387          * would not even hit this slow path.
 388          */
 389         dev_match = dev_match || (res.type == RTN_LOCAL &&
 390                                   dev == net->loopback_dev);
 391         if (dev_match) {
 392                 ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
 393                 return ret;
 394         }
 395         if (no_addr)
 396                 goto last_resort;
 397         if (rpf == 1)
 398                 goto e_rpf;
 399         fl4.flowi4_oif = dev->ifindex;
 400
 401         ret = 0;
 402         if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
 403                 if (res.type == RTN_UNICAST)
 404                         ret = FIB_RES_NHC(res)->nhc_scope >= RT_SCOPE_HOST;
 405         }
 406         return ret;
 407
 408 last_resort:
 409         if (rpf)
 410                 goto e_rpf;
 411         *itag = 0;
 412         return 0;
 413
 414 e_inval:
 415         return -EINVAL;
 416 e_rpf:
 417         return -EXDEV;
 418 }
 419
 420 /* Ignore rp_filter for packets protected by IPsec. */
 421 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 422                         u8 tos, int oif, struct net_device *dev,
 423                         struct in_device *idev, u32 *itag)
 424 {
 425         int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 426         struct net *net = dev_net(dev);
 427
 428         if (!r && !fib_num_tclassid_users(net) &&
 429             (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
 430                 if (IN_DEV_ACCEPT_LOCAL(idev))
 431                         goto ok;
 432                 /* with custom local routes in place, checking local addresses
 433                  * only will be too optimistic, with custom rules, checking
 434                  * local addresses only can be too strict, e.g. due to vrf
 435                  */
 436                 if (net->ipv4.fib_has_custom_local_routes ||
 437                     fib4_has_custom_rules(net))
 438                         goto full_check;
 439                 /* Within the same container, it is regarded as a martian source,
 440                  * and the same host but different containers are not.
 441                  */
 442                 if (inet_lookup_ifaddr_rcu(net, src))
 443                         return -EINVAL;
 444
 445 ok:
 446                 *itag = 0;
 447                 return 0;
 448         }
 449
 450 full_check:
 451         return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 452 }
 453
 454 static inline __be32 sk_extract_addr(struct sockaddr *addr)
 455 {
 456         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 457 }
 458
 459 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 460 {
 461         struct nlattr *nla;
 462
 463         nla = (struct nlattr *) ((char *) mx + len);
 464         nla->nla_type = type;
 465         nla->nla_len = nla_attr_size(4);
 466         *(u32 *) nla_data(nla) = value;
 467
 468         return len + nla_total_size(4);
 469 }
 470
 471 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 472                                  struct fib_config *cfg)
 473 {
 474         __be32 addr;
 475         int plen;
 476
 477         memset(cfg, 0, sizeof(*cfg));
 478         cfg->fc_nlinfo.nl_net = net;
 479
 480         if (rt->rt_dst.sa_family != AF_INET)
 481                 return -EAFNOSUPPORT;
 482
 483         /*
 484          * Check mask for validity:
 485          * a) it must be contiguous.
 486          * b) destination must have all host bits clear.
 487          * c) if application forgot to set correct family (AF_INET),
 488          *    reject request unless it is absolutely clear i.e.
 489          *    both family and mask are zero.
 490          */
 491         plen = 32;
 492         addr = sk_extract_addr(&rt->rt_dst);
 493         if (!(rt->rt_flags & RTF_HOST)) {
 494                 __be32 mask = sk_extract_addr(&rt->rt_genmask);
 495
 496                 if (rt->rt_genmask.sa_family != AF_INET) {
 497                         if (mask || rt->rt_genmask.sa_family)
 498                                 return -EAFNOSUPPORT;
 499                 }
 500
 501                 if (bad_mask(mask, addr))
 502                         return -EINVAL;
 503
 504                 plen = inet_mask_len(mask);
 505         }
 506
 507         cfg->fc_dst_len = plen;
 508         cfg->fc_dst = addr;
 509
 510         if (cmd != SIOCDELRT) {
 511                 cfg->fc_nlflags = NLM_F_CREATE;
 512                 cfg->fc_protocol = RTPROT_BOOT;
 513         }
 514
 515         if (rt->rt_metric)
 516                 cfg->fc_priority = rt->rt_metric - 1;
 517
 518         if (rt->rt_flags & RTF_REJECT) {
 519                 cfg->fc_scope = RT_SCOPE_HOST;
 520                 cfg->fc_type = RTN_UNREACHABLE;
 521                 return 0;
 522         }
 523
 524         cfg->fc_scope = RT_SCOPE_NOWHERE;
 525         cfg->fc_type = RTN_UNICAST;
 526
 527         if (rt->rt_dev) {
 528                 char *colon;
 529                 struct net_device *dev;
 530                 char devname[IFNAMSIZ];
 531
 532                 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 533                         return -EFAULT;
 534
 535                 devname[IFNAMSIZ-1] = 0;
 536                 colon = strchr(devname, ':');
 537                 if (colon)
 538                         *colon = 0;
 539                 dev = __dev_get_by_name(net, devname);
 540                 if (!dev)
 541                         return -ENODEV;
 542                 cfg->fc_oif = dev->ifindex;
 543                 cfg->fc_table = l3mdev_fib_table(dev);
 544                 if (colon) {
 545                         const struct in_ifaddr *ifa;
 546                         struct in_device *in_dev;
 547
 548                         in_dev = __in_dev_get_rtnl(dev);
 549                         if (!in_dev)
 550                                 return -ENODEV;
 551
 552                         *colon = ':';
 553
 554                         rcu_read_lock();
 555                         in_dev_for_each_ifa_rcu(ifa, in_dev) {
 556                                 if (strcmp(ifa->ifa_label, devname) == 0)
 557                                         break;
 558                         }
 559                         rcu_read_unlock();
 560
 561                         if (!ifa)
 562                                 return -ENODEV;
 563                         cfg->fc_prefsrc = ifa->ifa_local;
 564                 }
 565         }
 566
 567         addr = sk_extract_addr(&rt->rt_gateway);
 568         if (rt->rt_gateway.sa_family == AF_INET && addr) {
 569                 unsigned int addr_type;
 570
 571                 cfg->fc_gw4 = addr;
 572                 cfg->fc_gw_family = AF_INET;
 573                 addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
 574                 if (rt->rt_flags & RTF_GATEWAY &&
 575                     addr_type == RTN_UNICAST)
 576                         cfg->fc_scope = RT_SCOPE_UNIVERSE;
 577         }
 578
 579         if (!cfg->fc_table)
 580                 cfg->fc_table = RT_TABLE_MAIN;
 581
 582         if (cmd == SIOCDELRT)
 583                 return 0;
 584
 585         if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw_family)
 586                 return -EINVAL;
 587
 588         if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 589                 cfg->fc_scope = RT_SCOPE_LINK;
 590
 591         if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 592                 struct nlattr *mx;
 593                 int len = 0;
 594
 595                 mx = kcalloc(3, nla_total_size(4), GFP_KERNEL);
 596                 if (!mx)
 597                         return -ENOMEM;
 598
 599                 if (rt->rt_flags & RTF_MTU)
 600                         len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 601
 602                 if (rt->rt_flags & RTF_WINDOW)
 603                         len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 604
 605                 if (rt->rt_flags & RTF_IRTT)
 606                         len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 607
 608                 cfg->fc_mx = mx;
 609                 cfg->fc_mx_len = len;
 610         }
 611
 612         return 0;
 613 }
 614
 615 /*
 616  * Handle IP routing ioctl calls.
 617  * These are used to manipulate the routing tables
 618  */
 619 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
 620 {
 621         struct fib_config cfg;
 622         int err;
 623
 624         switch (cmd) {
 625         case SIOCADDRT:         /* Add a route */
 626         case SIOCDELRT:         /* Delete a route */
 627                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 628                         return -EPERM;
 629
 630                 rtnl_lock();
 631                 err = rtentry_to_fib_config(net, cmd, rt, &cfg);
 632                 if (err == 0) {
 633                         struct fib_table *tb;
 634
 635                         if (cmd == SIOCDELRT) {
 636                                 tb = fib_get_table(net, cfg.fc_table);
 637                                 if (tb)
 638                                         err = fib_table_delete(net, tb, &cfg,
 639                                                                NULL);
 640                                 else
 641                                         err = -ESRCH;
 642                         } else {
 643                                 tb = fib_new_table(net, cfg.fc_table);
 644                                 if (tb)
 645                                         err = fib_table_insert(net, tb,
 646                                                                &cfg, NULL);
 647                                 else
 648                                         err = -ENOBUFS;
 649                         }
 650
 651                         /* allocated by rtentry_to_fib_config() */
 652                         kfree(cfg.fc_mx);
 653                 }
 654                 rtnl_unlock();
 655                 return err;
 656         }
 657         return -EINVAL;
 658 }
 659
 660 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 661         [RTA_UNSPEC]            = { .strict_start_type = RTA_DPORT + 1 },
 662         [RTA_DST]               = { .type = NLA_U32 },
 663         [RTA_SRC]               = { .type = NLA_U32 },
 664         [RTA_IIF]               = { .type = NLA_U32 },
 665         [RTA_OIF]               = { .type = NLA_U32 },
 666         [RTA_GATEWAY]           = { .type = NLA_U32 },
 667         [RTA_PRIORITY]          = { .type = NLA_U32 },
 668         [RTA_PREFSRC]           = { .type = NLA_U32 },
 669         [RTA_METRICS]           = { .type = NLA_NESTED },
 670         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 671         [RTA_FLOW]              = { .type = NLA_U32 },
 672         [RTA_ENCAP_TYPE]        = { .type = NLA_U16 },
 673         [RTA_ENCAP]             = { .type = NLA_NESTED },
 674         [RTA_UID]               = { .type = NLA_U32 },
 675         [RTA_MARK]              = { .type = NLA_U32 },
 676         [RTA_TABLE]             = { .type = NLA_U32 },
 677         [RTA_IP_PROTO]          = { .type = NLA_U8 },
 678         [RTA_SPORT]             = { .type = NLA_U16 },
 679         [RTA_DPORT]             = { .type = NLA_U16 },
 680         [RTA_NH_ID]             = { .type = NLA_U32 },
 681 };
 682
 683 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
 684                     struct netlink_ext_ack *extack)
 685 {
 686         struct rtvia *via;
 687         int alen;
 688
 689         if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
 690                 NL_SET_ERR_MSG(extack, "Invalid attribute length for RTA_VIA");
 691                 return -EINVAL;
 692         }
 693
 694         via = nla_data(nla);
 695         alen = nla_len(nla) - offsetof(struct rtvia, rtvia_addr);
 696
 697         switch (via->rtvia_family) {
 698         case AF_INET:
 699                 if (alen != sizeof(__be32)) {
 700                         NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_VIA");
 701                         return -EINVAL;
 702                 }
 703                 cfg->fc_gw_family = AF_INET;
 704                 cfg->fc_gw4 = *((__be32 *)via->rtvia_addr);
 705                 break;
 706         case AF_INET6:
 707 #if IS_ENABLED(CONFIG_IPV6)
 708                 if (alen != sizeof(struct in6_addr)) {
 709                         NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA");
 710                         return -EINVAL;
 711                 }
 712                 cfg->fc_gw_family = AF_INET6;
 713                 cfg->fc_gw6 = *((struct in6_addr *)via->rtvia_addr);
 714 #else
 715                 NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
 716                 return -EINVAL;
 717 #endif
 718                 break;
 719         default:
 720                 NL_SET_ERR_MSG(extack, "Unsupported address family in RTA_VIA");
 721                 return -EINVAL;
 722         }
 723
 724         return 0;
 725 }
 726
 727 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 728                              struct nlmsghdr *nlh, struct fib_config *cfg,
 729                              struct netlink_ext_ack *extack)
 730 {
 731         bool has_gw = false, has_via = false;
 732         struct nlattr *attr;
 733         int err, remaining;
 734         struct rtmsg *rtm;
 735
 736         err = nlmsg_validate_deprecated(nlh, sizeof(*rtm), RTA_MAX,
 737                                         rtm_ipv4_policy, extack);
 738         if (err < 0)
 739                 goto errout;
 740
 741         memset(cfg, 0, sizeof(*cfg));
 742
 743         rtm = nlmsg_data(nlh);
 744
 745         if (!inet_validate_dscp(rtm->rtm_tos)) {
 746                 NL_SET_ERR_MSG(extack,
 747                                "Invalid dsfield (tos): ECN bits must be 0");
 748                 err = -EINVAL;
 749                 goto errout;
 750         }
 751         cfg->fc_dscp = inet_dsfield_to_dscp(rtm->rtm_tos);
 752
 753         cfg->fc_dst_len = rtm->rtm_dst_len;
 754         cfg->fc_table = rtm->rtm_table;
 755         cfg->fc_protocol = rtm->rtm_protocol;
 756         cfg->fc_scope = rtm->rtm_scope;
 757         cfg->fc_type = rtm->rtm_type;
 758         cfg->fc_flags = rtm->rtm_flags;
 759         cfg->fc_nlflags = nlh->nlmsg_flags;
 760
 761         cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 762         cfg->fc_nlinfo.nlh = nlh;
 763         cfg->fc_nlinfo.nl_net = net;
 764
 765         if (cfg->fc_type > RTN_MAX) {
 766                 NL_SET_ERR_MSG(extack, "Invalid route type");
 767                 err = -EINVAL;
 768                 goto errout;
 769         }
 770
 771         nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 772                 switch (nla_type(attr)) {
 773                 case RTA_DST:
 774                         cfg->fc_dst = nla_get_be32(attr);
 775                         break;
 776                 case RTA_OIF:
 777                         cfg->fc_oif = nla_get_u32(attr);
 778                         break;
 779                 case RTA_GATEWAY:
 780                         has_gw = true;
 781                         cfg->fc_gw4 = nla_get_be32(attr);
 782                         if (cfg->fc_gw4)
 783                                 cfg->fc_gw_family = AF_INET;
 784                         break;
 785                 case RTA_VIA:
 786                         has_via = true;
 787                         err = fib_gw_from_via(cfg, attr, extack);
 788                         if (err)
 789                                 goto errout;
 790                         break;
 791                 case RTA_PRIORITY:
 792                         cfg->fc_priority = nla_get_u32(attr);
 793                         break;
 794                 case RTA_PREFSRC:
 795                         cfg->fc_prefsrc = nla_get_be32(attr);
 796                         break;
 797                 case RTA_METRICS:
 798                         cfg->fc_mx = nla_data(attr);
 799                         cfg->fc_mx_len = nla_len(attr);
 800                         break;
 801                 case RTA_MULTIPATH:
 802                         err = lwtunnel_valid_encap_type_attr(nla_data(attr),
 803                                                              nla_len(attr),
 804                                                              extack);
 805                         if (err < 0)
 806                                 goto errout;
 807                         cfg->fc_mp = nla_data(attr);
 808                         cfg->fc_mp_len = nla_len(attr);
 809                         break;
 810                 case RTA_FLOW:
 811                         cfg->fc_flow = nla_get_u32(attr);
 812                         break;
 813                 case RTA_TABLE:
 814                         cfg->fc_table = nla_get_u32(attr);
 815                         break;
 816                 case RTA_ENCAP:
 817                         cfg->fc_encap = attr;
 818                         break;
 819                 case RTA_ENCAP_TYPE:
 820                         cfg->fc_encap_type = nla_get_u16(attr);
 821                         err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
 822                                                         extack);
 823                         if (err < 0)
 824                                 goto errout;
 825                         break;
 826                 case RTA_NH_ID:
 827                         cfg->fc_nh_id = nla_get_u32(attr);
 828                         break;
 829                 }
 830         }
 831
 832         if (cfg->fc_nh_id) {
 833                 if (cfg->fc_oif || cfg->fc_gw_family ||
 834                     cfg->fc_encap || cfg->fc_mp) {
 835                         NL_SET_ERR_MSG(extack,
 836                                        "Nexthop specification and nexthop id are mutually exclusive");
 837                         return -EINVAL;
 838                 }
 839         }
 840
 841         if (has_gw && has_via) {
 842                 NL_SET_ERR_MSG(extack,
 843                                "Nexthop configuration can not contain both GATEWAY and VIA");
 844                 return -EINVAL;
 845         }
 846
 847         if (!cfg->fc_table)
 848                 cfg->fc_table = RT_TABLE_MAIN;
 849
 850         return 0;
 851 errout:
 852         return err;
 853 }
 854
 855 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 856                              struct netlink_ext_ack *extack)
 857 {
 858         struct net *net = sock_net(skb->sk);
 859         struct fib_config cfg;
 860         struct fib_table *tb;
 861         int err;
 862
 863         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 864         if (err < 0)
 865                 goto errout;
 866
 867         if (cfg.fc_nh_id && !nexthop_find_by_id(net, cfg.fc_nh_id)) {
 868                 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
 869                 err = -EINVAL;
 870                 goto errout;
 871         }
 872
 873         tb = fib_get_table(net, cfg.fc_table);
 874         if (!tb) {
 875                 NL_SET_ERR_MSG(extack, "FIB table does not exist");
 876                 err = -ESRCH;
 877                 goto errout;
 878         }
 879
 880         err = fib_table_delete(net, tb, &cfg, extack);
 881 errout:
 882         return err;
 883 }
 884
 885 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 886                              struct netlink_ext_ack *extack)
 887 {
 888         struct net *net = sock_net(skb->sk);
 889         struct fib_config cfg;
 890         struct fib_table *tb;
 891         int err;
 892
 893         err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
 894         if (err < 0)
 895                 goto errout;
 896
 897         tb = fib_new_table(net, cfg.fc_table);
 898         if (!tb) {
 899                 err = -ENOBUFS;
 900                 goto errout;
 901         }
 902
 903         err = fib_table_insert(net, tb, &cfg, extack);
 904         if (!err && cfg.fc_type == RTN_LOCAL)
 905                 net->ipv4.fib_has_custom_local_routes = true;
 906 errout:
 907         return err;
 908 }
 909
 910 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 911                           struct fib_dump_filter *filter,
 912                           struct netlink_callback *cb)
 913 {
 914         struct netlink_ext_ack *extack = cb->extack;
 915         struct nlattr *tb[RTA_MAX + 1];
 916         struct rtmsg *rtm;
 917         int err, i;
 918
 919         if (filter->rtnl_held)
 920                 ASSERT_RTNL();
 921
 922         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
 923                 NL_SET_ERR_MSG(extack, "Invalid header for FIB dump request");
 924                 return -EINVAL;
 925         }
 926
 927         rtm = nlmsg_data(nlh);
 928         if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
 929             rtm->rtm_scope) {
 930                 NL_SET_ERR_MSG(extack, "Invalid values in header for FIB dump request");
 931                 return -EINVAL;
 932         }
 933
 934         if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
 935                 NL_SET_ERR_MSG(extack, "Invalid flags for FIB dump request");
 936                 return -EINVAL;
 937         }
 938         if (rtm->rtm_flags & RTM_F_CLONED)
 939                 filter->dump_routes = false;
 940         else
 941                 filter->dump_exceptions = false;
 942
 943         filter->flags    = rtm->rtm_flags;
 944         filter->protocol = rtm->rtm_protocol;
 945         filter->rt_type  = rtm->rtm_type;
 946         filter->table_id = rtm->rtm_table;
 947
 948         err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
 949                                             rtm_ipv4_policy, extack);
 950         if (err < 0)
 951                 return err;
 952
 953         for (i = 0; i <= RTA_MAX; ++i) {
 954                 int ifindex;
 955
 956                 if (!tb[i])
 957                         continue;
 958
 959                 switch (i) {
 960                 case RTA_TABLE:
 961                         filter->table_id = nla_get_u32(tb[i]);
 962                         break;
 963                 case RTA_OIF:
 964                         ifindex = nla_get_u32(tb[i]);
 965                         if (filter->rtnl_held)
 966                                 filter->dev = __dev_get_by_index(net, ifindex);
 967                         else
 968                                 filter->dev = dev_get_by_index_rcu(net, ifindex);
 969                         if (!filter->dev)
 970                                 return -ENODEV;
 971                         break;
 972                 default:
 973                         NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
 974                         return -EINVAL;
 975                 }
 976         }
 977
 978         if (filter->flags || filter->protocol || filter->rt_type ||
 979             filter->table_id || filter->dev) {
 980                 filter->filter_set = 1;
 981                 cb->answer_flags = NLM_F_DUMP_FILTERED;
 982         }
 983
 984         return 0;
 985 }
 986 EXPORT_SYMBOL_GPL(ip_valid_fib_dump_req);
 987
 988 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 989 {
 990         struct fib_dump_filter filter = {
 991                 .dump_routes = true,
 992                 .dump_exceptions = true,
 993                 .rtnl_held = false,
 994         };
 995         const struct nlmsghdr *nlh = cb->nlh;
 996         struct net *net = sock_net(skb->sk);
 997         unsigned int h, s_h;
 998         unsigned int e = 0, s_e;
 999         struct fib_table *tb;
1000         struct hlist_head *head;
1001         int dumped = 0, err = 0;
1002
1003         rcu_read_lock();
1004         if (cb->strict_check) {
1005                 err = ip_valid_fib_dump_req(net, nlh, &filter, cb);
1006                 if (err < 0)
1007                         goto unlock;
1008         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
1009                 struct rtmsg *rtm = nlmsg_data(nlh);
1010
1011                 filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
1012         }
1013
1014         /* ipv4 does not use prefix flag */
1015         if (filter.flags & RTM_F_PREFIX)
1016                 goto unlock;
1017
1018         if (filter.table_id) {
1019                 tb = fib_get_table(net, filter.table_id);
1020                 if (!tb) {
1021                         if (rtnl_msg_family(cb->nlh) != PF_INET)
1022                                 goto unlock;
1023
1024                         NL_SET_ERR_MSG(cb->extack, "ipv4: FIB table does not exist");
1025                         err = -ENOENT;
1026                         goto unlock;
1027                 }
1028                 err = fib_table_dump(tb, skb, cb, &filter);
1029                 goto unlock;
1030         }
1031
1032         s_h = cb->args[0];
1033         s_e = cb->args[1];
1034
1035         err = 0;
1036         for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
1037                 e = 0;
1038                 head = &net->ipv4.fib_table_hash[h];
1039                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
1040                         if (e < s_e)
1041                                 goto next;
1042                         if (dumped)
1043                                 memset(&cb->args[2], 0, sizeof(cb->args) -
1044                                                  2 * sizeof(cb->args[0]));
1045                         err = fib_table_dump(tb, skb, cb, &filter);
1046                         if (err < 0)
1047                                 goto out;
1048                         dumped = 1;
1049 next:
1050                         e++;
1051                 }
1052         }
1053
1054         /* Don't let NLM_DONE coalesce into a message, even if it could.
1055          * Some user space expects NLM_DONE in a separate recv().
1056          */
1057         err = skb->len;
1058 out:
1059
1060         cb->args[1] = e;
1061         cb->args[0] = h;
1062
1063 unlock:
1064         rcu_read_unlock();
1065         return err;
1066 }
1067
1068 /* Prepare and feed intra-kernel routing request.
1069  * Really, it should be netlink message, but :-( netlink
1070  * can be not configured, so that we feed it directly
1071  * to fib engine. It is legal, because all events occur
1072  * only when netlink is already locked.
1073  */
1074 static void fib_magic(int cmd, int type, __be32 dst, int dst_len,
1075                       struct in_ifaddr *ifa, u32 rt_priority)
1076 {
1077         struct net *net = dev_net(ifa->ifa_dev->dev);
1078         u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
1079         struct fib_table *tb;
1080         struct fib_config cfg = {
1081                 .fc_protocol = RTPROT_KERNEL,
1082                 .fc_type = type,
1083                 .fc_dst = dst,
1084                 .fc_dst_len = dst_len,
1085                 .fc_priority = rt_priority,
1086                 .fc_prefsrc = ifa->ifa_local,
1087                 .fc_oif = ifa->ifa_dev->dev->ifindex,
1088                 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
1089                 .fc_nlinfo = {
1090                         .nl_net = net,
1091                 },
1092         };
1093
1094         if (!tb_id)
1095                 tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
1096
1097         tb = fib_new_table(net, tb_id);
1098         if (!tb)
1099                 return;
1100
1101         cfg.fc_table = tb->tb_id;
1102
1103         if (type != RTN_LOCAL)
1104                 cfg.fc_scope = RT_SCOPE_LINK;
1105         else
1106                 cfg.fc_scope = RT_SCOPE_HOST;
1107
1108         if (cmd == RTM_NEWROUTE)
1109                 fib_table_insert(net, tb, &cfg, NULL);
1110         else
1111                 fib_table_delete(net, tb, &cfg, NULL);
1112 }
1113
1114 void fib_add_ifaddr(struct in_ifaddr *ifa)
1115 {
1116         struct in_device *in_dev = ifa->ifa_dev;
1117         struct net_device *dev = in_dev->dev;
1118         struct in_ifaddr *prim = ifa;
1119         __be32 mask = ifa->ifa_mask;
1120         __be32 addr = ifa->ifa_local;
1121         __be32 prefix = ifa->ifa_address & mask;
1122
1123         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1124                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
1125                 if (!prim) {
1126                         pr_warn("%s: bug: prim == NULL\n", __func__);
1127                         return;
1128                 }
1129         }
1130
1131         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim, 0);
1132
1133         if (!(dev->flags & IFF_UP))
1134                 return;
1135
1136         /* Add broadcast address, if it is explicitly assigned. */
1137         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF)) {
1138                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1139                           prim, 0);
1140                 arp_invalidate(dev, ifa->ifa_broadcast, false);
1141         }
1142
1143         if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
1144             (prefix != addr || ifa->ifa_prefixlen < 32)) {
1145                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1146                         fib_magic(RTM_NEWROUTE,
1147                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1148                                   prefix, ifa->ifa_prefixlen, prim,
1149                                   ifa->ifa_rt_priority);
1150
1151                 /* Add the network broadcast address, when it makes sense */
1152                 if (ifa->ifa_prefixlen < 31) {
1153                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
1154                                   32, prim, 0);
1155                         arp_invalidate(dev, prefix | ~mask, false);
1156                 }
1157         }
1158 }
1159
1160 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric)
1161 {
1162         __be32 prefix = ifa->ifa_address & ifa->ifa_mask;
1163         struct in_device *in_dev = ifa->ifa_dev;
1164         struct net_device *dev = in_dev->dev;
1165
1166         if (!(dev->flags & IFF_UP) ||
1167             ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) ||
1168             ipv4_is_zeronet(prefix) ||
1169             (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32))
1170                 return;
1171
1172         /* add the new */
1173         fib_magic(RTM_NEWROUTE,
1174                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1175                   prefix, ifa->ifa_prefixlen, ifa, new_metric);
1176
1177         /* delete the old */
1178         fib_magic(RTM_DELROUTE,
1179                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1180                   prefix, ifa->ifa_prefixlen, ifa, ifa->ifa_rt_priority);
1181 }
1182
1183 /* Delete primary or secondary address.
1184  * Optionally, on secondary address promotion consider the addresses
1185  * from subnet iprim as deleted, even if they are in device list.
1186  * In this case the secondary ifa can be in device list.
1187  */
1188 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
1189 {
1190         struct in_device *in_dev = ifa->ifa_dev;
1191         struct net_device *dev = in_dev->dev;
1192         struct in_ifaddr *ifa1;
1193         struct in_ifaddr *prim = ifa, *prim1 = NULL;
1194         __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
1195         __be32 any = ifa->ifa_address & ifa->ifa_mask;
1196 #define LOCAL_OK        1
1197 #define BRD_OK          2
1198 #define BRD0_OK         4
1199 #define BRD1_OK         8
1200         unsigned int ok = 0;
1201         int subnet = 0;         /* Primary network */
1202         int gone = 1;           /* Address is missing */
1203         int same_prefsrc = 0;   /* Another primary with same IP */
1204
1205         if (ifa->ifa_flags & IFA_F_SECONDARY) {
1206                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
1207                 if (!prim) {
1208                         /* if the device has been deleted, we don't perform
1209                          * address promotion
1210                          */
1211                         if (!in_dev->dead)
1212                                 pr_warn("%s: bug: prim == NULL\n", __func__);
1213                         return;
1214                 }
1215                 if (iprim && iprim != prim) {
1216                         pr_warn("%s: bug: iprim != prim\n", __func__);
1217                         return;
1218                 }
1219         } else if (!ipv4_is_zeronet(any) &&
1220                    (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
1221                 if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
1222                         fib_magic(RTM_DELROUTE,
1223                                   dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
1224                                   any, ifa->ifa_prefixlen, prim, 0);
1225                 subnet = 1;
1226         }
1227
1228         if (in_dev->dead)
1229                 goto no_promotions;
1230
1231         /* Deletion is more complicated than add.
1232          * We should take care of not to delete too much :-)
1233          *
1234          * Scan address list to be sure that addresses are really gone.
1235          */
1236         rcu_read_lock();
1237         in_dev_for_each_ifa_rcu(ifa1, in_dev) {
1238                 if (ifa1 == ifa) {
1239                         /* promotion, keep the IP */
1240                         gone = 0;
1241                         continue;
1242                 }
1243                 /* Ignore IFAs from our subnet */
1244                 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
1245                     inet_ifa_match(ifa1->ifa_address, iprim))
1246                         continue;
1247
1248                 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
1249                 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
1250                         /* Another address from our subnet? */
1251                         if (ifa1->ifa_mask == prim->ifa_mask &&
1252                             inet_ifa_match(ifa1->ifa_address, prim))
1253                                 prim1 = prim;
1254                         else {
1255                                 /* We reached the secondaries, so
1256                                  * same_prefsrc should be determined.
1257                                  */
1258                                 if (!same_prefsrc)
1259                                         continue;
1260                                 /* Search new prim1 if ifa1 is not
1261                                  * using the current prim1
1262                                  */
1263                                 if (!prim1 ||
1264                                     ifa1->ifa_mask != prim1->ifa_mask ||
1265                                     !inet_ifa_match(ifa1->ifa_address, prim1))
1266                                         prim1 = inet_ifa_byprefix(in_dev,
1267                                                         ifa1->ifa_address,
1268                                                         ifa1->ifa_mask);
1269                                 if (!prim1)
1270                                         continue;
1271                                 if (prim1->ifa_local != prim->ifa_local)
1272                                         continue;
1273                         }
1274                 } else {
1275                         if (prim->ifa_local != ifa1->ifa_local)
1276                                 continue;
1277                         prim1 = ifa1;
1278                         if (prim != prim1)
1279                                 same_prefsrc = 1;
1280                 }
1281                 if (ifa->ifa_local == ifa1->ifa_local)
1282                         ok |= LOCAL_OK;
1283                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1284                         ok |= BRD_OK;
1285                 if (brd == ifa1->ifa_broadcast)
1286                         ok |= BRD1_OK;
1287                 if (any == ifa1->ifa_broadcast)
1288                         ok |= BRD0_OK;
1289                 /* primary has network specific broadcasts */
1290                 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1291                         __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1292                         __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1293
1294                         if (!ipv4_is_zeronet(any1)) {
1295                                 if (ifa->ifa_broadcast == brd1 ||
1296                                     ifa->ifa_broadcast == any1)
1297                                         ok |= BRD_OK;
1298                                 if (brd == brd1 || brd == any1)
1299                                         ok |= BRD1_OK;
1300                                 if (any == brd1 || any == any1)
1301                                         ok |= BRD0_OK;
1302                         }
1303                 }
1304         }
1305         rcu_read_unlock();
1306
1307 no_promotions:
1308         if (!(ok & BRD_OK))
1309                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32,
1310                           prim, 0);
1311         if (subnet && ifa->ifa_prefixlen < 31) {
1312                 if (!(ok & BRD1_OK))
1313                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32,
1314                                   prim, 0);
1315                 if (!(ok & BRD0_OK))
1316                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32,
1317                                   prim, 0);
1318         }
1319         if (!(ok & LOCAL_OK)) {
1320                 unsigned int addr_type;
1321
1322                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim, 0);
1323
1324                 /* Check, that this local address finally disappeared. */
1325                 addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1326                                                      ifa->ifa_local);
1327                 if (gone && addr_type != RTN_LOCAL) {
1328                         /* And the last, but not the least thing.
1329                          * We must flush stray FIB entries.
1330                          *
1331                          * First of all, we scan fib_info list searching
1332                          * for stray nexthop entries, then ignite fib_flush.
1333                          */
1334                         if (fib_sync_down_addr(dev, ifa->ifa_local))
1335                                 fib_flush(dev_net(dev));
1336                 }
1337         }
1338 #undef LOCAL_OK
1339 #undef BRD_OK
1340 #undef BRD0_OK
1341 #undef BRD1_OK
1342 }
1343
1344 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1345 {
1346
1347         struct fib_result       res;
1348         struct flowi4           fl4 = {
1349                 .flowi4_mark = frn->fl_mark,
1350                 .daddr = frn->fl_addr,
1351                 .flowi4_tos = frn->fl_tos,
1352                 .flowi4_scope = frn->fl_scope,
1353         };
1354         struct fib_table *tb;
1355
1356         rcu_read_lock();
1357
1358         tb = fib_get_table(net, frn->tb_id_in);
1359
1360         frn->err = -ENOENT;
1361         if (tb) {
1362                 local_bh_disable();
1363
1364                 frn->tb_id = tb->tb_id;
1365                 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1366
1367                 if (!frn->err) {
1368                         frn->prefixlen = res.prefixlen;
1369                         frn->nh_sel = res.nh_sel;
1370                         frn->type = res.type;
1371                         frn->scope = res.scope;
1372                 }
1373                 local_bh_enable();
1374         }
1375
1376         rcu_read_unlock();
1377 }
1378
1379 static void nl_fib_input(struct sk_buff *skb)
1380 {
1381         struct net *net;
1382         struct fib_result_nl *frn;
1383         struct nlmsghdr *nlh;
1384         u32 portid;
1385
1386         net = sock_net(skb->sk);
1387         nlh = nlmsg_hdr(skb);
1388         if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1389             skb->len < nlh->nlmsg_len ||
1390             nlmsg_len(nlh) < sizeof(*frn))
1391                 return;
1392
1393         skb = netlink_skb_clone(skb, GFP_KERNEL);
1394         if (!skb)
1395                 return;
1396         nlh = nlmsg_hdr(skb);
1397
1398         frn = nlmsg_data(nlh);
1399         nl_fib_lookup(net, frn);
1400
1401         portid = NETLINK_CB(skb).portid;      /* netlink portid */
1402         NETLINK_CB(skb).portid = 0;        /* from kernel */
1403         NETLINK_CB(skb).dst_group = 0;  /* unicast */
1404         nlmsg_unicast(net->ipv4.fibnl, skb, portid);
1405 }
1406
1407 static int __net_init nl_fib_lookup_init(struct net *net)
1408 {
1409         struct sock *sk;
1410         struct netlink_kernel_cfg cfg = {
1411                 .input  = nl_fib_input,
1412         };
1413
1414         sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1415         if (!sk)
1416                 return -EAFNOSUPPORT;
1417         net->ipv4.fibnl = sk;
1418         return 0;
1419 }
1420
1421 static void nl_fib_lookup_exit(struct net *net)
1422 {
1423         netlink_kernel_release(net->ipv4.fibnl);
1424         net->ipv4.fibnl = NULL;
1425 }
1426
1427 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1428                            bool force)
1429 {
1430         if (fib_sync_down_dev(dev, event, force))
1431                 fib_flush(dev_net(dev));
1432         else
1433                 rt_cache_flush(dev_net(dev));
1434         arp_ifdown(dev);
1435 }
1436
1437 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1438 {
1439         struct in_ifaddr *ifa = ptr;
1440         struct net_device *dev = ifa->ifa_dev->dev;
1441         struct net *net = dev_net(dev);
1442
1443         switch (event) {
1444         case NETDEV_UP:
1445                 fib_add_ifaddr(ifa);
1446 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1447                 fib_sync_up(dev, RTNH_F_DEAD);
1448 #endif
1449                 atomic_inc(&net->ipv4.dev_addr_genid);
1450                 rt_cache_flush(dev_net(dev));
1451                 break;
1452         case NETDEV_DOWN:
1453                 fib_del_ifaddr(ifa, NULL);
1454                 atomic_inc(&net->ipv4.dev_addr_genid);
1455                 if (!ifa->ifa_dev->ifa_list) {
1456                         /* Last address was deleted from this interface.
1457                          * Disable IP.
1458                          */
1459                         fib_disable_ip(dev, event, true);
1460                 } else {
1461                         rt_cache_flush(dev_net(dev));
1462                 }
1463                 break;
1464         }
1465         return NOTIFY_DONE;
1466 }
1467
1468 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1469 {
1470         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1471         struct netdev_notifier_changeupper_info *upper_info = ptr;
1472         struct netdev_notifier_info_ext *info_ext = ptr;
1473         struct in_device *in_dev;
1474         struct net *net = dev_net(dev);
1475         struct in_ifaddr *ifa;
1476         unsigned int flags;
1477
1478         if (event == NETDEV_UNREGISTER) {
1479                 fib_disable_ip(dev, event, true);
1480                 rt_flush_dev(dev);
1481                 return NOTIFY_DONE;
1482         }
1483
1484         in_dev = __in_dev_get_rtnl(dev);
1485         if (!in_dev)
1486                 return NOTIFY_DONE;
1487
1488         switch (event) {
1489         case NETDEV_UP:
1490                 in_dev_for_each_ifa_rtnl(ifa, in_dev) {
1491                         fib_add_ifaddr(ifa);
1492                 }
1493 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1494                 fib_sync_up(dev, RTNH_F_DEAD);
1495 #endif
1496                 atomic_inc(&net->ipv4.dev_addr_genid);
1497                 rt_cache_flush(net);
1498                 break;
1499         case NETDEV_DOWN:
1500                 fib_disable_ip(dev, event, false);
1501                 break;
1502         case NETDEV_CHANGE:
1503                 flags = dev_get_flags(dev);
1504                 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1505                         fib_sync_up(dev, RTNH_F_LINKDOWN);
1506                 else
1507                         fib_sync_down_dev(dev, event, false);
1508                 rt_cache_flush(net);
1509                 break;
1510         case NETDEV_CHANGEMTU:
1511                 fib_sync_mtu(dev, info_ext->ext.mtu);
1512                 rt_cache_flush(net);
1513                 break;
1514         case NETDEV_CHANGEUPPER:
1515                 upper_info = ptr;
1516                 /* flush all routes if dev is linked to or unlinked from
1517                  * an L3 master device (e.g., VRF)
1518                  */
1519                 if (upper_info->upper_dev &&
1520                     netif_is_l3_master(upper_info->upper_dev))
1521                         fib_disable_ip(dev, NETDEV_DOWN, true);
1522                 break;
1523         }
1524         return NOTIFY_DONE;
1525 }
1526
1527 static struct notifier_block fib_inetaddr_notifier = {
1528         .notifier_call = fib_inetaddr_event,
1529 };
1530
1531 static struct notifier_block fib_netdev_notifier = {
1532         .notifier_call = fib_netdev_event,
1533 };
1534
1535 static int __net_init ip_fib_net_init(struct net *net)
1536 {
1537         int err;
1538         size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1539
1540         err = fib4_notifier_init(net);
1541         if (err)
1542                 return err;
1543
1544 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1545         /* Default to 3-tuple */
1546         net->ipv4.sysctl_fib_multipath_hash_fields =
1547                 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
1548 #endif
1549
1550         /* Avoid false sharing : Use at least a full cache line */
1551         size = max_t(size_t, size, L1_CACHE_BYTES);
1552
1553         net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1554         if (!net->ipv4.fib_table_hash) {
1555                 err = -ENOMEM;
1556                 goto err_table_hash_alloc;
1557         }
1558
1559         err = fib4_rules_init(net);
1560         if (err < 0)
1561                 goto err_rules_init;
1562         return 0;
1563
1564 err_rules_init:
1565         kfree(net->ipv4.fib_table_hash);
1566 err_table_hash_alloc:
1567         fib4_notifier_exit(net);
1568         return err;
1569 }
1570
1571 static void ip_fib_net_exit(struct net *net)
1572 {
1573         int i;
1574
1575         ASSERT_RTNL();
1576 #ifdef CONFIG_IP_MULTIPLE_TABLES
1577         RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1578         RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1579 #endif
1580         /* Destroy the tables in reverse order to guarantee that the
1581          * local table, ID 255, is destroyed before the main table, ID
1582          * 254. This is necessary as the local table may contain
1583          * references to data contained in the main table.
1584          */
1585         for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1586                 struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1587                 struct hlist_node *tmp;
1588                 struct fib_table *tb;
1589
1590                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1591                         hlist_del(&tb->tb_hlist);
1592                         fib_table_flush(net, tb, true);
1593                         fib_free_table(tb);
1594                 }
1595         }
1596
1597 #ifdef CONFIG_IP_MULTIPLE_TABLES
1598         fib4_rules_exit(net);
1599 #endif
1600
1601         kfree(net->ipv4.fib_table_hash);
1602         fib4_notifier_exit(net);
1603 }
1604
1605 static int __net_init fib_net_init(struct net *net)
1606 {
1607         int error;
1608
1609 #ifdef CONFIG_IP_ROUTE_CLASSID
1610         atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
1611 #endif
1612         error = ip_fib_net_init(net);
1613         if (error < 0)
1614                 goto out;
1615         error = nl_fib_lookup_init(net);
1616         if (error < 0)
1617                 goto out_nlfl;
1618         error = fib_proc_init(net);
1619         if (error < 0)
1620                 goto out_proc;
1621 out:
1622         return error;
1623
1624 out_proc:
1625         nl_fib_lookup_exit(net);
1626 out_nlfl:
1627         rtnl_lock();
1628         ip_fib_net_exit(net);
1629         rtnl_unlock();
1630         goto out;
1631 }
1632
1633 static void __net_exit fib_net_exit(struct net *net)
1634 {
1635         fib_proc_exit(net);
1636         nl_fib_lookup_exit(net);
1637 }
1638
1639 static void __net_exit fib_net_exit_batch(struct list_head *net_list)
1640 {
1641         struct net *net;
1642
1643         rtnl_lock();
1644         list_for_each_entry(net, net_list, exit_list)
1645                 ip_fib_net_exit(net);
1646
1647         rtnl_unlock();
1648 }
1649
1650 static struct pernet_operations fib_net_ops = {
1651         .init = fib_net_init,
1652         .exit = fib_net_exit,
1653         .exit_batch = fib_net_exit_batch,
1654 };
1655
1656 void __init ip_fib_init(void)
1657 {
1658         fib_trie_init();
1659
1660         register_pernet_subsys(&fib_net_ops);
1661
1662         register_netdevice_notifier(&fib_netdev_notifier);
1663         register_inetaddr_notifier(&fib_inetaddr_notifier);
1664
1665         rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1666         rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1667         rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib,
1668                       RTNL_FLAG_DUMP_UNLOCKED);
1669 }