linux/net/ipv4/fib_frontend.c
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              IPv4 Forwarding Information Base: FIB frontend.
   7 *
   8 * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   9 *
  10 *              This program is free software; you can redistribute it and/or
  11 *              modify it under the terms of the GNU General Public License
  12 *              as published by the Free Software Foundation; either version
  13 *              2 of the License, or (at your option) any later version.
  14 */
  15
  16#include <linux/module.h>
  17#include <asm/uaccess.h>
  18#include <asm/system.h>
  19#include <linux/bitops.h>
  20#include <linux/capability.h>
  21#include <linux/types.h>
  22#include <linux/kernel.h>
  23#include <linux/mm.h>
  24#include <linux/string.h>
  25#include <linux/socket.h>
  26#include <linux/sockios.h>
  27#include <linux/errno.h>
  28#include <linux/in.h>
  29#include <linux/inet.h>
  30#include <linux/inetdevice.h>
  31#include <linux/netdevice.h>
  32#include <linux/if_addr.h>
  33#include <linux/if_arp.h>
  34#include <linux/skbuff.h>
  35#include <linux/init.h>
  36#include <linux/list.h>
  37#include <linux/slab.h>
  38
  39#include <net/ip.h>
  40#include <net/protocol.h>
  41#include <net/route.h>
  42#include <net/tcp.h>
  43#include <net/sock.h>
  44#include <net/arp.h>
  45#include <net/ip_fib.h>
  46#include <net/rtnetlink.h>
  47#include <net/xfrm.h>
  48
  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        local_table = fib_trie_table(RT_TABLE_LOCAL);
  56        if (local_table == NULL)
  57                return -ENOMEM;
  58
  59        main_table  = fib_trie_table(RT_TABLE_MAIN);
  60        if (main_table == NULL)
  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        kfree(local_table);
  71        return -ENOMEM;
  72}
  73#else
  74
  75struct fib_table *fib_new_table(struct net *net, u32 id)
  76{
  77        struct fib_table *tb;
  78        unsigned int h;
  79
  80        if (id == 0)
  81                id = RT_TABLE_MAIN;
  82        tb = fib_get_table(net, id);
  83        if (tb)
  84                return tb;
  85
  86        tb = fib_trie_table(id);
  87        if (!tb)
  88                return NULL;
  89        h = id & (FIB_TABLE_HASHSZ - 1);
  90        hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
  91        return tb;
  92}
  93
  94struct fib_table *fib_get_table(struct net *net, u32 id)
  95{
  96        struct fib_table *tb;
  97        struct hlist_node *node;
  98        struct hlist_head *head;
  99        unsigned int h;
 100
 101        if (id == 0)
 102                id = RT_TABLE_MAIN;
 103        h = id & (FIB_TABLE_HASHSZ - 1);
 104
 105        rcu_read_lock();
 106        head = &net->ipv4.fib_table_hash[h];
 107        hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
 108                if (tb->tb_id == id) {
 109                        rcu_read_unlock();
 110                        return tb;
 111                }
 112        }
 113        rcu_read_unlock();
 114        return NULL;
 115}
 116#endif /* CONFIG_IP_MULTIPLE_TABLES */
 117
 118static void fib_flush(struct net *net)
 119{
 120        int flushed = 0;
 121        struct fib_table *tb;
 122        struct hlist_node *node;
 123        struct hlist_head *head;
 124        unsigned int h;
 125
 126        for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 127                head = &net->ipv4.fib_table_hash[h];
 128                hlist_for_each_entry(tb, node, head, tb_hlist)
 129                        flushed += fib_table_flush(tb);
 130        }
 131
 132        if (flushed)
 133                rt_cache_flush(net, -1);
 134}
 135
 136/*
 137 * Find address type as if only "dev" was present in the system. If
 138 * on_dev is NULL then all interfaces are taken into consideration.
 139 */
 140static inline unsigned __inet_dev_addr_type(struct net *net,
 141                                            const struct net_device *dev,
 142                                            __be32 addr)
 143{
 144        struct flowi4           fl4 = { .daddr = addr };
 145        struct fib_result       res;
 146        unsigned ret = RTN_BROADCAST;
 147        struct fib_table *local_table;
 148
 149        if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
 150                return RTN_BROADCAST;
 151        if (ipv4_is_multicast(addr))
 152                return RTN_MULTICAST;
 153
 154#ifdef CONFIG_IP_MULTIPLE_TABLES
 155        res.r = NULL;
 156#endif
 157
 158        local_table = fib_get_table(net, RT_TABLE_LOCAL);
 159        if (local_table) {
 160                ret = RTN_UNICAST;
 161                rcu_read_lock();
 162                if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
 163                        if (!dev || dev == res.fi->fib_dev)
 164                                ret = res.type;
 165                }
 166                rcu_read_unlock();
 167        }
 168        return ret;
 169}
 170
 171unsigned int inet_addr_type(struct net *net, __be32 addr)
 172{
 173        return __inet_dev_addr_type(net, NULL, addr);
 174}
 175EXPORT_SYMBOL(inet_addr_type);
 176
 177unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 178                                __be32 addr)
 179{
 180        return __inet_dev_addr_type(net, dev, addr);
 181}
 182EXPORT_SYMBOL(inet_dev_addr_type);
 183
 184/* Given (packet source, input interface) and optional (dst, oif, tos):
 185 * - (main) check, that source is valid i.e. not broadcast or our local
 186 *   address.
 187 * - figure out what "logical" interface this packet arrived
 188 *   and calculate "specific destination" address.
 189 * - check, that packet arrived from expected physical interface.
 190 * called with rcu_read_lock()
 191 */
 192int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, u8 tos,
 193                        int oif, struct net_device *dev, __be32 *spec_dst,
 194                        u32 *itag)
 195{
 196        struct in_device *in_dev;
 197        struct flowi4 fl4;
 198        struct fib_result res;
 199        int no_addr, rpf, accept_local;
 200        bool dev_match;
 201        int ret;
 202        struct net *net;
 203
 204        fl4.flowi4_oif = 0;
 205        fl4.flowi4_iif = oif;
 206        fl4.daddr = src;
 207        fl4.saddr = dst;
 208        fl4.flowi4_tos = tos;
 209        fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 210
 211        no_addr = rpf = accept_local = 0;
 212        in_dev = __in_dev_get_rcu(dev);
 213        if (in_dev) {
 214                no_addr = in_dev->ifa_list == NULL;
 215
 216                /* Ignore rp_filter for packets protected by IPsec. */
 217                rpf = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(in_dev);
 218
 219                accept_local = IN_DEV_ACCEPT_LOCAL(in_dev);
 220                fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
 221        }
 222
 223        if (in_dev == NULL)
 224                goto e_inval;
 225
 226        net = dev_net(dev);
 227        if (fib_lookup(net, &fl4, &res))
 228                goto last_resort;
 229        if (res.type != RTN_UNICAST) {
 230                if (res.type != RTN_LOCAL || !accept_local)
 231                        goto e_inval;
 232        }
 233        *spec_dst = FIB_RES_PREFSRC(net, res);
 234        fib_combine_itag(itag, &res);
 235        dev_match = false;
 236
 237#ifdef CONFIG_IP_ROUTE_MULTIPATH
 238        for (ret = 0; ret < res.fi->fib_nhs; ret++) {
 239                struct fib_nh *nh = &res.fi->fib_nh[ret];
 240
 241                if (nh->nh_dev == dev) {
 242                        dev_match = true;
 243                        break;
 244                }
 245        }
 246#else
 247        if (FIB_RES_DEV(res) == dev)
 248                dev_match = true;
 249#endif
 250        if (dev_match) {
 251                ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 252                return ret;
 253        }
 254        if (no_addr)
 255                goto last_resort;
 256        if (rpf == 1)
 257                goto e_rpf;
 258        fl4.flowi4_oif = dev->ifindex;
 259
 260        ret = 0;
 261        if (fib_lookup(net, &fl4, &res) == 0) {
 262                if (res.type == RTN_UNICAST) {
 263                        *spec_dst = FIB_RES_PREFSRC(net, res);
 264                        ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 265                }
 266        }
 267        return ret;
 268
 269last_resort:
 270        if (rpf)
 271                goto e_rpf;
 272        *spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
 273        *itag = 0;
 274        return 0;
 275
 276e_inval:
 277        return -EINVAL;
 278e_rpf:
 279        return -EXDEV;
 280}
 281
 282static inline __be32 sk_extract_addr(struct sockaddr *addr)
 283{
 284        return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 285}
 286
 287static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 288{
 289        struct nlattr *nla;
 290
 291        nla = (struct nlattr *) ((char *) mx + len);
 292        nla->nla_type = type;
 293        nla->nla_len = nla_attr_size(4);
 294        *(u32 *) nla_data(nla) = value;
 295
 296        return len + nla_total_size(4);
 297}
 298
 299static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 300                                 struct fib_config *cfg)
 301{
 302        __be32 addr;
 303        int plen;
 304
 305        memset(cfg, 0, sizeof(*cfg));
 306        cfg->fc_nlinfo.nl_net = net;
 307
 308        if (rt->rt_dst.sa_family != AF_INET)
 309                return -EAFNOSUPPORT;
 310
 311        /*
 312         * Check mask for validity:
 313         * a) it must be contiguous.
 314         * b) destination must have all host bits clear.
 315         * c) if application forgot to set correct family (AF_INET),
 316         *    reject request unless it is absolutely clear i.e.
 317         *    both family and mask are zero.
 318         */
 319        plen = 32;
 320        addr = sk_extract_addr(&rt->rt_dst);
 321        if (!(rt->rt_flags & RTF_HOST)) {
 322                __be32 mask = sk_extract_addr(&rt->rt_genmask);
 323
 324                if (rt->rt_genmask.sa_family != AF_INET) {
 325                        if (mask || rt->rt_genmask.sa_family)
 326                                return -EAFNOSUPPORT;
 327                }
 328
 329                if (bad_mask(mask, addr))
 330                        return -EINVAL;
 331
 332                plen = inet_mask_len(mask);
 333        }
 334
 335        cfg->fc_dst_len = plen;
 336        cfg->fc_dst = addr;
 337
 338        if (cmd != SIOCDELRT) {
 339                cfg->fc_nlflags = NLM_F_CREATE;
 340                cfg->fc_protocol = RTPROT_BOOT;
 341        }
 342
 343        if (rt->rt_metric)
 344                cfg->fc_priority = rt->rt_metric - 1;
 345
 346        if (rt->rt_flags & RTF_REJECT) {
 347                cfg->fc_scope = RT_SCOPE_HOST;
 348                cfg->fc_type = RTN_UNREACHABLE;
 349                return 0;
 350        }
 351
 352        cfg->fc_scope = RT_SCOPE_NOWHERE;
 353        cfg->fc_type = RTN_UNICAST;
 354
 355        if (rt->rt_dev) {
 356                char *colon;
 357                struct net_device *dev;
 358                char devname[IFNAMSIZ];
 359
 360                if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 361                        return -EFAULT;
 362
 363                devname[IFNAMSIZ-1] = 0;
 364                colon = strchr(devname, ':');
 365                if (colon)
 366                        *colon = 0;
 367                dev = __dev_get_by_name(net, devname);
 368                if (!dev)
 369                        return -ENODEV;
 370                cfg->fc_oif = dev->ifindex;
 371                if (colon) {
 372                        struct in_ifaddr *ifa;
 373                        struct in_device *in_dev = __in_dev_get_rtnl(dev);
 374                        if (!in_dev)
 375                                return -ENODEV;
 376                        *colon = ':';
 377                        for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
 378                                if (strcmp(ifa->ifa_label, devname) == 0)
 379                                        break;
 380                        if (ifa == NULL)
 381                                return -ENODEV;
 382                        cfg->fc_prefsrc = ifa->ifa_local;
 383                }
 384        }
 385
 386        addr = sk_extract_addr(&rt->rt_gateway);
 387        if (rt->rt_gateway.sa_family == AF_INET && addr) {
 388                cfg->fc_gw = addr;
 389                if (rt->rt_flags & RTF_GATEWAY &&
 390                    inet_addr_type(net, addr) == RTN_UNICAST)
 391                        cfg->fc_scope = RT_SCOPE_UNIVERSE;
 392        }
 393
 394        if (cmd == SIOCDELRT)
 395                return 0;
 396
 397        if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
 398                return -EINVAL;
 399
 400        if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 401                cfg->fc_scope = RT_SCOPE_LINK;
 402
 403        if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 404                struct nlattr *mx;
 405                int len = 0;
 406
 407                mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
 408                if (mx == NULL)
 409                        return -ENOMEM;
 410
 411                if (rt->rt_flags & RTF_MTU)
 412                        len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 413
 414                if (rt->rt_flags & RTF_WINDOW)
 415                        len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 416
 417                if (rt->rt_flags & RTF_IRTT)
 418                        len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 419
 420                cfg->fc_mx = mx;
 421                cfg->fc_mx_len = len;
 422        }
 423
 424        return 0;
 425}
 426
 427/*
 428 * Handle IP routing ioctl calls.
 429 * These are used to manipulate the routing tables
 430 */
 431int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 432{
 433        struct fib_config cfg;
 434        struct rtentry rt;
 435        int err;
 436
 437        switch (cmd) {
 438        case SIOCADDRT:         /* Add a route */
 439        case SIOCDELRT:         /* Delete a route */
 440                if (!capable(CAP_NET_ADMIN))
 441                        return -EPERM;
 442
 443                if (copy_from_user(&rt, arg, sizeof(rt)))
 444                        return -EFAULT;
 445
 446                rtnl_lock();
 447                err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
 448                if (err == 0) {
 449                        struct fib_table *tb;
 450
 451                        if (cmd == SIOCDELRT) {
 452                                tb = fib_get_table(net, cfg.fc_table);
 453                                if (tb)
 454                                        err = fib_table_delete(tb, &cfg);
 455                                else
 456                                        err = -ESRCH;
 457                        } else {
 458                                tb = fib_new_table(net, cfg.fc_table);
 459                                if (tb)
 460                                        err = fib_table_insert(tb, &cfg);
 461                                else
 462                                        err = -ENOBUFS;
 463                        }
 464
 465                        /* allocated by rtentry_to_fib_config() */
 466                        kfree(cfg.fc_mx);
 467                }
 468                rtnl_unlock();
 469                return err;
 470        }
 471        return -EINVAL;
 472}
 473
 474const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 475        [RTA_DST]               = { .type = NLA_U32 },
 476        [RTA_SRC]               = { .type = NLA_U32 },
 477        [RTA_IIF]               = { .type = NLA_U32 },
 478        [RTA_OIF]               = { .type = NLA_U32 },
 479        [RTA_GATEWAY]           = { .type = NLA_U32 },
 480        [RTA_PRIORITY]          = { .type = NLA_U32 },
 481        [RTA_PREFSRC]           = { .type = NLA_U32 },
 482        [RTA_METRICS]           = { .type = NLA_NESTED },
 483        [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 484        [RTA_FLOW]              = { .type = NLA_U32 },
 485};
 486
 487static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 488                             struct nlmsghdr *nlh, struct fib_config *cfg)
 489{
 490        struct nlattr *attr;
 491        int err, remaining;
 492        struct rtmsg *rtm;
 493
 494        err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
 495        if (err < 0)
 496                goto errout;
 497
 498        memset(cfg, 0, sizeof(*cfg));
 499
 500        rtm = nlmsg_data(nlh);
 501        cfg->fc_dst_len = rtm->rtm_dst_len;
 502        cfg->fc_tos = rtm->rtm_tos;
 503        cfg->fc_table = rtm->rtm_table;
 504        cfg->fc_protocol = rtm->rtm_protocol;
 505        cfg->fc_scope = rtm->rtm_scope;
 506        cfg->fc_type = rtm->rtm_type;
 507        cfg->fc_flags = rtm->rtm_flags;
 508        cfg->fc_nlflags = nlh->nlmsg_flags;
 509
 510        cfg->fc_nlinfo.pid = NETLINK_CB(skb).pid;
 511        cfg->fc_nlinfo.nlh = nlh;
 512        cfg->fc_nlinfo.nl_net = net;
 513
 514        if (cfg->fc_type > RTN_MAX) {
 515                err = -EINVAL;
 516                goto errout;
 517        }
 518
 519        nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 520                switch (nla_type(attr)) {
 521                case RTA_DST:
 522                        cfg->fc_dst = nla_get_be32(attr);
 523                        break;
 524                case RTA_OIF:
 525                        cfg->fc_oif = nla_get_u32(attr);
 526                        break;
 527                case RTA_GATEWAY:
 528                        cfg->fc_gw = nla_get_be32(attr);
 529                        break;
 530                case RTA_PRIORITY:
 531                        cfg->fc_priority = nla_get_u32(attr);
 532                        break;
 533                case RTA_PREFSRC:
 534                        cfg->fc_prefsrc = nla_get_be32(attr);
 535                        break;
 536                case RTA_METRICS:
 537                        cfg->fc_mx = nla_data(attr);
 538                        cfg->fc_mx_len = nla_len(attr);
 539                        break;
 540                case RTA_MULTIPATH:
 541                        cfg->fc_mp = nla_data(attr);
 542                        cfg->fc_mp_len = nla_len(attr);
 543                        break;
 544                case RTA_FLOW:
 545                        cfg->fc_flow = nla_get_u32(attr);
 546                        break;
 547                case RTA_TABLE:
 548                        cfg->fc_table = nla_get_u32(attr);
 549                        break;
 550                }
 551        }
 552
 553        return 0;
 554errout:
 555        return err;
 556}
 557
 558static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 559{
 560        struct net *net = sock_net(skb->sk);
 561        struct fib_config cfg;
 562        struct fib_table *tb;
 563        int err;
 564
 565        err = rtm_to_fib_config(net, skb, nlh, &cfg);
 566        if (err < 0)
 567                goto errout;
 568
 569        tb = fib_get_table(net, cfg.fc_table);
 570        if (tb == NULL) {
 571                err = -ESRCH;
 572                goto errout;
 573        }
 574
 575        err = fib_table_delete(tb, &cfg);
 576errout:
 577        return err;
 578}
 579
 580static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 581{
 582        struct net *net = sock_net(skb->sk);
 583        struct fib_config cfg;
 584        struct fib_table *tb;
 585        int err;
 586
 587        err = rtm_to_fib_config(net, skb, nlh, &cfg);
 588        if (err < 0)
 589                goto errout;
 590
 591        tb = fib_new_table(net, cfg.fc_table);
 592        if (tb == NULL) {
 593                err = -ENOBUFS;
 594                goto errout;
 595        }
 596
 597        err = fib_table_insert(tb, &cfg);
 598errout:
 599        return err;
 600}
 601
 602static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 603{
 604        struct net *net = sock_net(skb->sk);
 605        unsigned int h, s_h;
 606        unsigned int e = 0, s_e;
 607        struct fib_table *tb;
 608        struct hlist_node *node;
 609        struct hlist_head *head;
 610        int dumped = 0;
 611
 612        if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
 613            ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
 614                return ip_rt_dump(skb, cb);
 615
 616        s_h = cb->args[0];
 617        s_e = cb->args[1];
 618
 619        for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 620                e = 0;
 621                head = &net->ipv4.fib_table_hash[h];
 622                hlist_for_each_entry(tb, node, head, tb_hlist) {
 623                        if (e < s_e)
 624                                goto next;
 625                        if (dumped)
 626                                memset(&cb->args[2], 0, sizeof(cb->args) -
 627                                                 2 * sizeof(cb->args[0]));
 628                        if (fib_table_dump(tb, skb, cb) < 0)
 629                                goto out;
 630                        dumped = 1;
 631next:
 632                        e++;
 633                }
 634        }
 635out:
 636        cb->args[1] = e;
 637        cb->args[0] = h;
 638
 639        return skb->len;
 640}
 641
 642/* Prepare and feed intra-kernel routing request.
 643 * Really, it should be netlink message, but :-( netlink
 644 * can be not configured, so that we feed it directly
 645 * to fib engine. It is legal, because all events occur
 646 * only when netlink is already locked.
 647 */
 648static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
 649{
 650        struct net *net = dev_net(ifa->ifa_dev->dev);
 651        struct fib_table *tb;
 652        struct fib_config cfg = {
 653                .fc_protocol = RTPROT_KERNEL,
 654                .fc_type = type,
 655                .fc_dst = dst,
 656                .fc_dst_len = dst_len,
 657                .fc_prefsrc = ifa->ifa_local,
 658                .fc_oif = ifa->ifa_dev->dev->ifindex,
 659                .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
 660                .fc_nlinfo = {
 661                        .nl_net = net,
 662                },
 663        };
 664
 665        if (type == RTN_UNICAST)
 666                tb = fib_new_table(net, RT_TABLE_MAIN);
 667        else
 668                tb = fib_new_table(net, RT_TABLE_LOCAL);
 669
 670        if (tb == NULL)
 671                return;
 672
 673        cfg.fc_table = tb->tb_id;
 674
 675        if (type != RTN_LOCAL)
 676                cfg.fc_scope = RT_SCOPE_LINK;
 677        else
 678                cfg.fc_scope = RT_SCOPE_HOST;
 679
 680        if (cmd == RTM_NEWROUTE)
 681                fib_table_insert(tb, &cfg);
 682        else
 683                fib_table_delete(tb, &cfg);
 684}
 685
 686void fib_add_ifaddr(struct in_ifaddr *ifa)
 687{
 688        struct in_device *in_dev = ifa->ifa_dev;
 689        struct net_device *dev = in_dev->dev;
 690        struct in_ifaddr *prim = ifa;
 691        __be32 mask = ifa->ifa_mask;
 692        __be32 addr = ifa->ifa_local;
 693        __be32 prefix = ifa->ifa_address & mask;
 694
 695        if (ifa->ifa_flags & IFA_F_SECONDARY) {
 696                prim = inet_ifa_byprefix(in_dev, prefix, mask);
 697                if (prim == NULL) {
 698                        printk(KERN_WARNING "fib_add_ifaddr: bug: prim == NULL\n");
 699                        return;
 700                }
 701        }
 702
 703        fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
 704
 705        if (!(dev->flags & IFF_UP))
 706                return;
 707
 708        /* Add broadcast address, if it is explicitly assigned. */
 709        if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
 710                fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 711
 712        if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
 713            (prefix != addr || ifa->ifa_prefixlen < 32)) {
 714                fib_magic(RTM_NEWROUTE,
 715                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 716                          prefix, ifa->ifa_prefixlen, prim);
 717
 718                /* Add network specific broadcasts, when it takes a sense */
 719                if (ifa->ifa_prefixlen < 31) {
 720                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
 721                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
 722                                  32, prim);
 723                }
 724        }
 725}
 726
 727/* Delete primary or secondary address.
 728 * Optionally, on secondary address promotion consider the addresses
 729 * from subnet iprim as deleted, even if they are in device list.
 730 * In this case the secondary ifa can be in device list.
 731 */
 732void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
 733{
 734        struct in_device *in_dev = ifa->ifa_dev;
 735        struct net_device *dev = in_dev->dev;
 736        struct in_ifaddr *ifa1;
 737        struct in_ifaddr *prim = ifa, *prim1 = NULL;
 738        __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
 739        __be32 any = ifa->ifa_address & ifa->ifa_mask;
 740#define LOCAL_OK        1
 741#define BRD_OK          2
 742#define BRD0_OK         4
 743#define BRD1_OK         8
 744        unsigned ok = 0;
 745        int subnet = 0;         /* Primary network */
 746        int gone = 1;           /* Address is missing */
 747        int same_prefsrc = 0;   /* Another primary with same IP */
 748
 749        if (ifa->ifa_flags & IFA_F_SECONDARY) {
 750                prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
 751                if (prim == NULL) {
 752                        printk(KERN_WARNING "fib_del_ifaddr: bug: prim == NULL\n");
 753                        return;
 754                }
 755                if (iprim && iprim != prim) {
 756                        printk(KERN_WARNING "fib_del_ifaddr: bug: iprim != prim\n");
 757                        return;
 758                }
 759        } else if (!ipv4_is_zeronet(any) &&
 760                   (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
 761                fib_magic(RTM_DELROUTE,
 762                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 763                          any, ifa->ifa_prefixlen, prim);
 764                subnet = 1;
 765        }
 766
 767        /* Deletion is more complicated than add.
 768         * We should take care of not to delete too much :-)
 769         *
 770         * Scan address list to be sure that addresses are really gone.
 771         */
 772
 773        for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
 774                if (ifa1 == ifa) {
 775                        /* promotion, keep the IP */
 776                        gone = 0;
 777                        continue;
 778                }
 779                /* Ignore IFAs from our subnet */
 780                if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
 781                    inet_ifa_match(ifa1->ifa_address, iprim))
 782                        continue;
 783
 784                /* Ignore ifa1 if it uses different primary IP (prefsrc) */
 785                if (ifa1->ifa_flags & IFA_F_SECONDARY) {
 786                        /* Another address from our subnet? */
 787                        if (ifa1->ifa_mask == prim->ifa_mask &&
 788                            inet_ifa_match(ifa1->ifa_address, prim))
 789                                prim1 = prim;
 790                        else {
 791                                /* We reached the secondaries, so
 792                                 * same_prefsrc should be determined.
 793                                 */
 794                                if (!same_prefsrc)
 795                                        continue;
 796                                /* Search new prim1 if ifa1 is not
 797                                 * using the current prim1
 798                                 */
 799                                if (!prim1 ||
 800                                    ifa1->ifa_mask != prim1->ifa_mask ||
 801                                    !inet_ifa_match(ifa1->ifa_address, prim1))
 802                                        prim1 = inet_ifa_byprefix(in_dev,
 803                                                        ifa1->ifa_address,
 804                                                        ifa1->ifa_mask);
 805                                if (!prim1)
 806                                        continue;
 807                                if (prim1->ifa_local != prim->ifa_local)
 808                                        continue;
 809                        }
 810                } else {
 811                        if (prim->ifa_local != ifa1->ifa_local)
 812                                continue;
 813                        prim1 = ifa1;
 814                        if (prim != prim1)
 815                                same_prefsrc = 1;
 816                }
 817                if (ifa->ifa_local == ifa1->ifa_local)
 818                        ok |= LOCAL_OK;
 819                if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
 820                        ok |= BRD_OK;
 821                if (brd == ifa1->ifa_broadcast)
 822                        ok |= BRD1_OK;
 823                if (any == ifa1->ifa_broadcast)
 824                        ok |= BRD0_OK;
 825                /* primary has network specific broadcasts */
 826                if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
 827                        __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
 828                        __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
 829
 830                        if (!ipv4_is_zeronet(any1)) {
 831                                if (ifa->ifa_broadcast == brd1 ||
 832                                    ifa->ifa_broadcast == any1)
 833                                        ok |= BRD_OK;
 834                                if (brd == brd1 || brd == any1)
 835                                        ok |= BRD1_OK;
 836                                if (any == brd1 || any == any1)
 837                                        ok |= BRD0_OK;
 838                        }
 839                }
 840        }
 841
 842        if (!(ok & BRD_OK))
 843                fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 844        if (subnet && ifa->ifa_prefixlen < 31) {
 845                if (!(ok & BRD1_OK))
 846                        fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
 847                if (!(ok & BRD0_OK))
 848                        fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
 849        }
 850        if (!(ok & LOCAL_OK)) {
 851                fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
 852
 853                /* Check, that this local address finally disappeared. */
 854                if (gone &&
 855                    inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) {
 856                        /* And the last, but not the least thing.
 857                         * We must flush stray FIB entries.
 858                         *
 859                         * First of all, we scan fib_info list searching
 860                         * for stray nexthop entries, then ignite fib_flush.
 861                         */
 862                        if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local))
 863                                fib_flush(dev_net(dev));
 864                }
 865        }
 866#undef LOCAL_OK
 867#undef BRD_OK
 868#undef BRD0_OK
 869#undef BRD1_OK
 870}
 871
 872static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
 873{
 874
 875        struct fib_result       res;
 876        struct flowi4           fl4 = {
 877                .flowi4_mark = frn->fl_mark,
 878                .daddr = frn->fl_addr,
 879                .flowi4_tos = frn->fl_tos,
 880                .flowi4_scope = frn->fl_scope,
 881        };
 882
 883#ifdef CONFIG_IP_MULTIPLE_TABLES
 884        res.r = NULL;
 885#endif
 886
 887        frn->err = -ENOENT;
 888        if (tb) {
 889                local_bh_disable();
 890
 891                frn->tb_id = tb->tb_id;
 892                rcu_read_lock();
 893                frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
 894
 895                if (!frn->err) {
 896                        frn->prefixlen = res.prefixlen;
 897                        frn->nh_sel = res.nh_sel;
 898                        frn->type = res.type;
 899                        frn->scope = res.scope;
 900                }
 901                rcu_read_unlock();
 902                local_bh_enable();
 903        }
 904}
 905
 906static void nl_fib_input(struct sk_buff *skb)
 907{
 908        struct net *net;
 909        struct fib_result_nl *frn;
 910        struct nlmsghdr *nlh;
 911        struct fib_table *tb;
 912        u32 pid;
 913
 914        net = sock_net(skb->sk);
 915        nlh = nlmsg_hdr(skb);
 916        if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
 917            nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn)))
 918                return;
 919
 920        skb = skb_clone(skb, GFP_KERNEL);
 921        if (skb == NULL)
 922                return;
 923        nlh = nlmsg_hdr(skb);
 924
 925        frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
 926        tb = fib_get_table(net, frn->tb_id_in);
 927
 928        nl_fib_lookup(frn, tb);
 929
 930        pid = NETLINK_CB(skb).pid;      /* pid of sending process */
 931        NETLINK_CB(skb).pid = 0;        /* from kernel */
 932        NETLINK_CB(skb).dst_group = 0;  /* unicast */
 933        netlink_unicast(net->ipv4.fibnl, skb, pid, MSG_DONTWAIT);
 934}
 935
 936static int __net_init nl_fib_lookup_init(struct net *net)
 937{
 938        struct sock *sk;
 939        sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, 0,
 940                                   nl_fib_input, NULL, THIS_MODULE);
 941        if (sk == NULL)
 942                return -EAFNOSUPPORT;
 943        net->ipv4.fibnl = sk;
 944        return 0;
 945}
 946
 947static void nl_fib_lookup_exit(struct net *net)
 948{
 949        netlink_kernel_release(net->ipv4.fibnl);
 950        net->ipv4.fibnl = NULL;
 951}
 952
 953static void fib_disable_ip(struct net_device *dev, int force, int delay)
 954{
 955        if (fib_sync_down_dev(dev, force))
 956                fib_flush(dev_net(dev));
 957        rt_cache_flush(dev_net(dev), delay);
 958        arp_ifdown(dev);
 959}
 960
 961static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
 962{
 963        struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
 964        struct net_device *dev = ifa->ifa_dev->dev;
 965        struct net *net = dev_net(dev);
 966
 967        switch (event) {
 968        case NETDEV_UP:
 969                fib_add_ifaddr(ifa);
 970#ifdef CONFIG_IP_ROUTE_MULTIPATH
 971                fib_sync_up(dev);
 972#endif
 973                atomic_inc(&net->ipv4.dev_addr_genid);
 974                rt_cache_flush(dev_net(dev), -1);
 975                break;
 976        case NETDEV_DOWN:
 977                fib_del_ifaddr(ifa, NULL);
 978                atomic_inc(&net->ipv4.dev_addr_genid);
 979                if (ifa->ifa_dev->ifa_list == NULL) {
 980                        /* Last address was deleted from this interface.
 981                         * Disable IP.
 982                         */
 983                        fib_disable_ip(dev, 1, 0);
 984                } else {
 985                        rt_cache_flush(dev_net(dev), -1);
 986                }
 987                break;
 988        }
 989        return NOTIFY_DONE;
 990}
 991
 992static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
 993{
 994        struct net_device *dev = ptr;
 995        struct in_device *in_dev = __in_dev_get_rtnl(dev);
 996        struct net *net = dev_net(dev);
 997
 998        if (event == NETDEV_UNREGISTER) {
 999                fib_disable_ip(dev, 2, -1);
1000                return NOTIFY_DONE;
1001        }
1002
1003        if (!in_dev)
1004                return NOTIFY_DONE;
1005
1006        switch (event) {
1007        case NETDEV_UP:
1008                for_ifa(in_dev) {
1009                        fib_add_ifaddr(ifa);
1010                } endfor_ifa(in_dev);
1011#ifdef CONFIG_IP_ROUTE_MULTIPATH
1012                fib_sync_up(dev);
1013#endif
1014                atomic_inc(&net->ipv4.dev_addr_genid);
1015                rt_cache_flush(dev_net(dev), -1);
1016                break;
1017        case NETDEV_DOWN:
1018                fib_disable_ip(dev, 0, 0);
1019                break;
1020        case NETDEV_CHANGEMTU:
1021        case NETDEV_CHANGE:
1022                rt_cache_flush(dev_net(dev), 0);
1023                break;
1024        case NETDEV_UNREGISTER_BATCH:
1025                /* The batch unregister is only called on the first
1026                 * device in the list of devices being unregistered.
1027                 * Therefore we should not pass dev_net(dev) in here.
1028                 */
1029                rt_cache_flush_batch(NULL);
1030                break;
1031        }
1032        return NOTIFY_DONE;
1033}
1034
1035static struct notifier_block fib_inetaddr_notifier = {
1036        .notifier_call = fib_inetaddr_event,
1037};
1038
1039static struct notifier_block fib_netdev_notifier = {
1040        .notifier_call = fib_netdev_event,
1041};
1042
1043static int __net_init ip_fib_net_init(struct net *net)
1044{
1045        int err;
1046        size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1047
1048        /* Avoid false sharing : Use at least a full cache line */
1049        size = max_t(size_t, size, L1_CACHE_BYTES);
1050
1051        net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1052        if (net->ipv4.fib_table_hash == NULL)
1053                return -ENOMEM;
1054
1055        err = fib4_rules_init(net);
1056        if (err < 0)
1057                goto fail;
1058        return 0;
1059
1060fail:
1061        kfree(net->ipv4.fib_table_hash);
1062        return err;
1063}
1064
1065static void ip_fib_net_exit(struct net *net)
1066{
1067        unsigned int i;
1068
1069#ifdef CONFIG_IP_MULTIPLE_TABLES
1070        fib4_rules_exit(net);
1071#endif
1072
1073        rtnl_lock();
1074        for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
1075                struct fib_table *tb;
1076                struct hlist_head *head;
1077                struct hlist_node *node, *tmp;
1078
1079                head = &net->ipv4.fib_table_hash[i];
1080                hlist_for_each_entry_safe(tb, node, tmp, head, tb_hlist) {
1081                        hlist_del(node);
1082                        fib_table_flush(tb);
1083                        fib_free_table(tb);
1084                }
1085        }
1086        rtnl_unlock();
1087        kfree(net->ipv4.fib_table_hash);
1088}
1089
1090static int __net_init fib_net_init(struct net *net)
1091{
1092        int error;
1093
1094        error = ip_fib_net_init(net);
1095        if (error < 0)
1096                goto out;
1097        error = nl_fib_lookup_init(net);
1098        if (error < 0)
1099                goto out_nlfl;
1100        error = fib_proc_init(net);
1101        if (error < 0)
1102                goto out_proc;
1103out:
1104        return error;
1105
1106out_proc:
1107        nl_fib_lookup_exit(net);
1108out_nlfl:
1109        ip_fib_net_exit(net);
1110        goto out;
1111}
1112
1113static void __net_exit fib_net_exit(struct net *net)
1114{
1115        fib_proc_exit(net);
1116        nl_fib_lookup_exit(net);
1117        ip_fib_net_exit(net);
1118}
1119
1120static struct pernet_operations fib_net_ops = {
1121        .init = fib_net_init,
1122        .exit = fib_net_exit,
1123};
1124
1125void __init ip_fib_init(void)
1126{
1127        rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL);
1128        rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL);
1129        rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL);
1130
1131        register_pernet_subsys(&fib_net_ops);
1132        register_netdevice_notifier(&fib_netdev_notifier);
1133        register_inetaddr_notifier(&fib_inetaddr_notifier);
1134
1135        fib_trie_init();
1136}
1137