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