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 <linux/bitops.h>
  19#include <linux/capability.h>
  20#include <linux/types.h>
  21#include <linux/kernel.h>
  22#include <linux/mm.h>
  23#include <linux/string.h>
  24#include <linux/socket.h>
  25#include <linux/sockios.h>
  26#include <linux/errno.h>
  27#include <linux/in.h>
  28#include <linux/inet.h>
  29#include <linux/inetdevice.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_addr.h>
  32#include <linux/if_arp.h>
  33#include <linux/skbuff.h>
  34#include <linux/cache.h>
  35#include <linux/init.h>
  36#include <linux/list.h>
  37#include <linux/slab.h>
  38
  39#include <net/ip.h>
  40#include <net/protocol.h>
  41#include <net/route.h>
  42#include <net/tcp.h>
  43#include <net/sock.h>
  44#include <net/arp.h>
  45#include <net/ip_fib.h>
  46#include <net/rtnetlink.h>
  47#include <net/xfrm.h>
  48
  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
  90        switch (id) {
  91        case RT_TABLE_LOCAL:
  92                net->ipv4.fib_local = tb;
  93                break;
  94
  95        case RT_TABLE_MAIN:
  96                net->ipv4.fib_main = tb;
  97                break;
  98
  99        case RT_TABLE_DEFAULT:
 100                net->ipv4.fib_default = tb;
 101                break;
 102
 103        default:
 104                break;
 105        }
 106
 107        h = id & (FIB_TABLE_HASHSZ - 1);
 108        hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
 109        return tb;
 110}
 111
 112struct fib_table *fib_get_table(struct net *net, u32 id)
 113{
 114        struct fib_table *tb;
 115        struct hlist_node *node;
 116        struct hlist_head *head;
 117        unsigned int h;
 118
 119        if (id == 0)
 120                id = RT_TABLE_MAIN;
 121        h = id & (FIB_TABLE_HASHSZ - 1);
 122
 123        rcu_read_lock();
 124        head = &net->ipv4.fib_table_hash[h];
 125        hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
 126                if (tb->tb_id == id) {
 127                        rcu_read_unlock();
 128                        return tb;
 129                }
 130        }
 131        rcu_read_unlock();
 132        return NULL;
 133}
 134#endif /* CONFIG_IP_MULTIPLE_TABLES */
 135
 136static void fib_flush(struct net *net)
 137{
 138        int flushed = 0;
 139        struct fib_table *tb;
 140        struct hlist_node *node;
 141        struct hlist_head *head;
 142        unsigned int h;
 143
 144        for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 145                head = &net->ipv4.fib_table_hash[h];
 146                hlist_for_each_entry(tb, node, head, tb_hlist)
 147                        flushed += fib_table_flush(tb);
 148        }
 149
 150        if (flushed)
 151                rt_cache_flush(net);
 152}
 153
 154/*
 155 * Find address type as if only "dev" was present in the system. If
 156 * on_dev is NULL then all interfaces are taken into consideration.
 157 */
 158static inline unsigned int __inet_dev_addr_type(struct net *net,
 159                                                const struct net_device *dev,
 160                                                __be32 addr)
 161{
 162        struct flowi4           fl4 = { .daddr = addr };
 163        struct fib_result       res;
 164        unsigned int ret = RTN_BROADCAST;
 165        struct fib_table *local_table;
 166
 167        if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
 168                return RTN_BROADCAST;
 169        if (ipv4_is_multicast(addr))
 170                return RTN_MULTICAST;
 171
 172        local_table = fib_get_table(net, RT_TABLE_LOCAL);
 173        if (local_table) {
 174                ret = RTN_UNICAST;
 175                rcu_read_lock();
 176                if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
 177                        if (!dev || dev == res.fi->fib_dev)
 178                                ret = res.type;
 179                }
 180                rcu_read_unlock();
 181        }
 182        return ret;
 183}
 184
 185unsigned int inet_addr_type(struct net *net, __be32 addr)
 186{
 187        return __inet_dev_addr_type(net, NULL, addr);
 188}
 189EXPORT_SYMBOL(inet_addr_type);
 190
 191unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 192                                __be32 addr)
 193{
 194        return __inet_dev_addr_type(net, dev, addr);
 195}
 196EXPORT_SYMBOL(inet_dev_addr_type);
 197
 198__be32 fib_compute_spec_dst(struct sk_buff *skb)
 199{
 200        struct net_device *dev = skb->dev;
 201        struct in_device *in_dev;
 202        struct fib_result res;
 203        struct rtable *rt;
 204        struct flowi4 fl4;
 205        struct net *net;
 206        int scope;
 207
 208        rt = skb_rtable(skb);
 209        if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
 210            RTCF_LOCAL)
 211                return ip_hdr(skb)->daddr;
 212
 213        in_dev = __in_dev_get_rcu(dev);
 214        BUG_ON(!in_dev);
 215
 216        net = dev_net(dev);
 217
 218        scope = RT_SCOPE_UNIVERSE;
 219        if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 220                fl4.flowi4_oif = 0;
 221                fl4.flowi4_iif = net->loopback_dev->ifindex;
 222                fl4.daddr = ip_hdr(skb)->saddr;
 223                fl4.saddr = 0;
 224                fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
 225                fl4.flowi4_scope = scope;
 226                fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
 227                if (!fib_lookup(net, &fl4, &res))
 228                        return FIB_RES_PREFSRC(net, res);
 229        } else {
 230                scope = RT_SCOPE_LINK;
 231        }
 232
 233        return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 234}
 235
 236/* Given (packet source, input interface) and optional (dst, oif, tos):
 237 * - (main) check, that source is valid i.e. not broadcast or our local
 238 *   address.
 239 * - figure out what "logical" interface this packet arrived
 240 *   and calculate "specific destination" address.
 241 * - check, that packet arrived from expected physical interface.
 242 * called with rcu_read_lock()
 243 */
 244static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 245                                 u8 tos, int oif, struct net_device *dev,
 246                                 int rpf, struct in_device *idev, u32 *itag)
 247{
 248        int ret, no_addr, accept_local;
 249        struct fib_result res;
 250        struct flowi4 fl4;
 251        struct net *net;
 252        bool dev_match;
 253
 254        fl4.flowi4_oif = 0;
 255        fl4.flowi4_iif = oif;
 256        fl4.daddr = src;
 257        fl4.saddr = dst;
 258        fl4.flowi4_tos = tos;
 259        fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 260
 261        no_addr = idev->ifa_list == NULL;
 262
 263        accept_local = IN_DEV_ACCEPT_LOCAL(idev);
 264        fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
 265
 266        net = dev_net(dev);
 267        if (fib_lookup(net, &fl4, &res))
 268                goto last_resort;
 269        if (res.type != RTN_UNICAST) {
 270                if (res.type != RTN_LOCAL || !accept_local)
 271                        goto e_inval;
 272        }
 273        fib_combine_itag(itag, &res);
 274        dev_match = false;
 275
 276#ifdef CONFIG_IP_ROUTE_MULTIPATH
 277        for (ret = 0; ret < res.fi->fib_nhs; ret++) {
 278                struct fib_nh *nh = &res.fi->fib_nh[ret];
 279
 280                if (nh->nh_dev == dev) {
 281                        dev_match = true;
 282                        break;
 283                }
 284        }
 285#else
 286        if (FIB_RES_DEV(res) == dev)
 287                dev_match = true;
 288#endif
 289        if (dev_match) {
 290                ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 291                return ret;
 292        }
 293        if (no_addr)
 294                goto last_resort;
 295        if (rpf == 1)
 296                goto e_rpf;
 297        fl4.flowi4_oif = dev->ifindex;
 298
 299        ret = 0;
 300        if (fib_lookup(net, &fl4, &res) == 0) {
 301                if (res.type == RTN_UNICAST)
 302                        ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 303        }
 304        return ret;
 305
 306last_resort:
 307        if (rpf)
 308                goto e_rpf;
 309        *itag = 0;
 310        return 0;
 311
 312e_inval:
 313        return -EINVAL;
 314e_rpf:
 315        return -EXDEV;
 316}
 317
 318/* Ignore rp_filter for packets protected by IPsec. */
 319int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 320                        u8 tos, int oif, struct net_device *dev,
 321                        struct in_device *idev, u32 *itag)
 322{
 323        int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 324
 325        if (!r && !fib_num_tclassid_users(dev_net(dev))) {
 326                *itag = 0;
 327                return 0;
 328        }
 329        return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 330}
 331
 332static inline __be32 sk_extract_addr(struct sockaddr *addr)
 333{
 334        return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 335}
 336
 337static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 338{
 339        struct nlattr *nla;
 340
 341        nla = (struct nlattr *) ((char *) mx + len);
 342        nla->nla_type = type;
 343        nla->nla_len = nla_attr_size(4);
 344        *(u32 *) nla_data(nla) = value;
 345
 346        return len + nla_total_size(4);
 347}
 348
 349static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 350                                 struct fib_config *cfg)
 351{
 352        __be32 addr;
 353        int plen;
 354
 355        memset(cfg, 0, sizeof(*cfg));
 356        cfg->fc_nlinfo.nl_net = net;
 357
 358        if (rt->rt_dst.sa_family != AF_INET)
 359                return -EAFNOSUPPORT;
 360
 361        /*
 362         * Check mask for validity:
 363         * a) it must be contiguous.
 364         * b) destination must have all host bits clear.
 365         * c) if application forgot to set correct family (AF_INET),
 366         *    reject request unless it is absolutely clear i.e.
 367         *    both family and mask are zero.
 368         */
 369        plen = 32;
 370        addr = sk_extract_addr(&rt->rt_dst);
 371        if (!(rt->rt_flags & RTF_HOST)) {
 372                __be32 mask = sk_extract_addr(&rt->rt_genmask);
 373
 374                if (rt->rt_genmask.sa_family != AF_INET) {
 375                        if (mask || rt->rt_genmask.sa_family)
 376                                return -EAFNOSUPPORT;
 377                }
 378
 379                if (bad_mask(mask, addr))
 380                        return -EINVAL;
 381
 382                plen = inet_mask_len(mask);
 383        }
 384
 385        cfg->fc_dst_len = plen;
 386        cfg->fc_dst = addr;
 387
 388        if (cmd != SIOCDELRT) {
 389                cfg->fc_nlflags = NLM_F_CREATE;
 390                cfg->fc_protocol = RTPROT_BOOT;
 391        }
 392
 393        if (rt->rt_metric)
 394                cfg->fc_priority = rt->rt_metric - 1;
 395
 396        if (rt->rt_flags & RTF_REJECT) {
 397                cfg->fc_scope = RT_SCOPE_HOST;
 398                cfg->fc_type = RTN_UNREACHABLE;
 399                return 0;
 400        }
 401
 402        cfg->fc_scope = RT_SCOPE_NOWHERE;
 403        cfg->fc_type = RTN_UNICAST;
 404
 405        if (rt->rt_dev) {
 406                char *colon;
 407                struct net_device *dev;
 408                char devname[IFNAMSIZ];
 409
 410                if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 411                        return -EFAULT;
 412
 413                devname[IFNAMSIZ-1] = 0;
 414                colon = strchr(devname, ':');
 415                if (colon)
 416                        *colon = 0;
 417                dev = __dev_get_by_name(net, devname);
 418                if (!dev)
 419                        return -ENODEV;
 420                cfg->fc_oif = dev->ifindex;
 421                if (colon) {
 422                        struct in_ifaddr *ifa;
 423                        struct in_device *in_dev = __in_dev_get_rtnl(dev);
 424                        if (!in_dev)
 425                                return -ENODEV;
 426                        *colon = ':';
 427                        for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
 428                                if (strcmp(ifa->ifa_label, devname) == 0)
 429                                        break;
 430                        if (ifa == NULL)
 431                                return -ENODEV;
 432                        cfg->fc_prefsrc = ifa->ifa_local;
 433                }
 434        }
 435
 436        addr = sk_extract_addr(&rt->rt_gateway);
 437        if (rt->rt_gateway.sa_family == AF_INET && addr) {
 438                cfg->fc_gw = addr;
 439                if (rt->rt_flags & RTF_GATEWAY &&
 440                    inet_addr_type(net, addr) == RTN_UNICAST)
 441                        cfg->fc_scope = RT_SCOPE_UNIVERSE;
 442        }
 443
 444        if (cmd == SIOCDELRT)
 445                return 0;
 446
 447        if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
 448                return -EINVAL;
 449
 450        if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 451                cfg->fc_scope = RT_SCOPE_LINK;
 452
 453        if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 454                struct nlattr *mx;
 455                int len = 0;
 456
 457                mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
 458                if (mx == NULL)
 459                        return -ENOMEM;
 460
 461                if (rt->rt_flags & RTF_MTU)
 462                        len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 463
 464                if (rt->rt_flags & RTF_WINDOW)
 465                        len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 466
 467                if (rt->rt_flags & RTF_IRTT)
 468                        len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 469
 470                cfg->fc_mx = mx;
 471                cfg->fc_mx_len = len;
 472        }
 473
 474        return 0;
 475}
 476
 477/*
 478 * Handle IP routing ioctl calls.
 479 * These are used to manipulate the routing tables
 480 */
 481int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 482{
 483        struct fib_config cfg;
 484        struct rtentry rt;
 485        int err;
 486
 487        switch (cmd) {
 488        case SIOCADDRT:         /* Add a route */
 489        case SIOCDELRT:         /* Delete a route */
 490                if (!capable(CAP_NET_ADMIN))
 491                        return -EPERM;
 492
 493                if (copy_from_user(&rt, arg, sizeof(rt)))
 494                        return -EFAULT;
 495
 496                rtnl_lock();
 497                err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
 498                if (err == 0) {
 499                        struct fib_table *tb;
 500
 501                        if (cmd == SIOCDELRT) {
 502                                tb = fib_get_table(net, cfg.fc_table);
 503                                if (tb)
 504                                        err = fib_table_delete(tb, &cfg);
 505                                else
 506                                        err = -ESRCH;
 507                        } else {
 508                                tb = fib_new_table(net, cfg.fc_table);
 509                                if (tb)
 510                                        err = fib_table_insert(tb, &cfg);
 511                                else
 512                                        err = -ENOBUFS;
 513                        }
 514
 515                        /* allocated by rtentry_to_fib_config() */
 516                        kfree(cfg.fc_mx);
 517                }
 518                rtnl_unlock();
 519                return err;
 520        }
 521        return -EINVAL;
 522}
 523
 524const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 525        [RTA_DST]               = { .type = NLA_U32 },
 526        [RTA_SRC]               = { .type = NLA_U32 },
 527        [RTA_IIF]               = { .type = NLA_U32 },
 528        [RTA_OIF]               = { .type = NLA_U32 },
 529        [RTA_GATEWAY]           = { .type = NLA_U32 },
 530        [RTA_PRIORITY]          = { .type = NLA_U32 },
 531        [RTA_PREFSRC]           = { .type = NLA_U32 },
 532        [RTA_METRICS]           = { .type = NLA_NESTED },
 533        [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 534        [RTA_FLOW]              = { .type = NLA_U32 },
 535};
 536
 537static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 538                             struct nlmsghdr *nlh, struct fib_config *cfg)
 539{
 540        struct nlattr *attr;
 541        int err, remaining;
 542        struct rtmsg *rtm;
 543
 544        err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
 545        if (err < 0)
 546                goto errout;
 547
 548        memset(cfg, 0, sizeof(*cfg));
 549
 550        rtm = nlmsg_data(nlh);
 551        cfg->fc_dst_len = rtm->rtm_dst_len;
 552        cfg->fc_tos = rtm->rtm_tos;
 553        cfg->fc_table = rtm->rtm_table;
 554        cfg->fc_protocol = rtm->rtm_protocol;
 555        cfg->fc_scope = rtm->rtm_scope;
 556        cfg->fc_type = rtm->rtm_type;
 557        cfg->fc_flags = rtm->rtm_flags;
 558        cfg->fc_nlflags = nlh->nlmsg_flags;
 559
 560        cfg->fc_nlinfo.pid = NETLINK_CB(skb).pid;
 561        cfg->fc_nlinfo.nlh = nlh;
 562        cfg->fc_nlinfo.nl_net = net;
 563
 564        if (cfg->fc_type > RTN_MAX) {
 565                err = -EINVAL;
 566                goto errout;
 567        }
 568
 569        nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 570                switch (nla_type(attr)) {
 571                case RTA_DST:
 572                        cfg->fc_dst = nla_get_be32(attr);
 573                        break;
 574                case RTA_OIF:
 575                        cfg->fc_oif = nla_get_u32(attr);
 576                        break;
 577                case RTA_GATEWAY:
 578                        cfg->fc_gw = nla_get_be32(attr);
 579                        break;
 580                case RTA_PRIORITY:
 581                        cfg->fc_priority = nla_get_u32(attr);
 582                        break;
 583                case RTA_PREFSRC:
 584                        cfg->fc_prefsrc = nla_get_be32(attr);
 585                        break;
 586                case RTA_METRICS:
 587                        cfg->fc_mx = nla_data(attr);
 588                        cfg->fc_mx_len = nla_len(attr);
 589                        break;
 590                case RTA_MULTIPATH:
 591                        cfg->fc_mp = nla_data(attr);
 592                        cfg->fc_mp_len = nla_len(attr);
 593                        break;
 594                case RTA_FLOW:
 595                        cfg->fc_flow = nla_get_u32(attr);
 596                        break;
 597                case RTA_TABLE:
 598                        cfg->fc_table = nla_get_u32(attr);
 599                        break;
 600                }
 601        }
 602
 603        return 0;
 604errout:
 605        return err;
 606}
 607
 608static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 609{
 610        struct net *net = sock_net(skb->sk);
 611        struct fib_config cfg;
 612        struct fib_table *tb;
 613        int err;
 614
 615        err = rtm_to_fib_config(net, skb, nlh, &cfg);
 616        if (err < 0)
 617                goto errout;
 618
 619        tb = fib_get_table(net, cfg.fc_table);
 620        if (tb == NULL) {
 621                err = -ESRCH;
 622                goto errout;
 623        }
 624
 625        err = fib_table_delete(tb, &cfg);
 626errout:
 627        return err;
 628}
 629
 630static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 631{
 632        struct net *net = sock_net(skb->sk);
 633        struct fib_config cfg;
 634        struct fib_table *tb;
 635        int err;
 636
 637        err = rtm_to_fib_config(net, skb, nlh, &cfg);
 638        if (err < 0)
 639                goto errout;
 640
 641        tb = fib_new_table(net, cfg.fc_table);
 642        if (tb == NULL) {
 643                err = -ENOBUFS;
 644                goto errout;
 645        }
 646
 647        err = fib_table_insert(tb, &cfg);
 648errout:
 649        return err;
 650}
 651
 652static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 653{
 654        struct net *net = sock_net(skb->sk);
 655        unsigned int h, s_h;
 656        unsigned int e = 0, s_e;
 657        struct fib_table *tb;
 658        struct hlist_node *node;
 659        struct hlist_head *head;
 660        int dumped = 0;
 661
 662        if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
 663            ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
 664                return ip_rt_dump(skb, cb);
 665
 666        s_h = cb->args[0];
 667        s_e = cb->args[1];
 668
 669        for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 670                e = 0;
 671                head = &net->ipv4.fib_table_hash[h];
 672                hlist_for_each_entry(tb, node, head, tb_hlist) {
 673                        if (e < s_e)
 674                                goto next;
 675                        if (dumped)
 676                                memset(&cb->args[2], 0, sizeof(cb->args) -
 677                                                 2 * sizeof(cb->args[0]));
 678                        if (fib_table_dump(tb, skb, cb) < 0)
 679                                goto out;
 680                        dumped = 1;
 681next:
 682                        e++;
 683                }
 684        }
 685out:
 686        cb->args[1] = e;
 687        cb->args[0] = h;
 688
 689        return skb->len;
 690}
 691
 692/* Prepare and feed intra-kernel routing request.
 693 * Really, it should be netlink message, but :-( netlink
 694 * can be not configured, so that we feed it directly
 695 * to fib engine. It is legal, because all events occur
 696 * only when netlink is already locked.
 697 */
 698static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
 699{
 700        struct net *net = dev_net(ifa->ifa_dev->dev);
 701        struct fib_table *tb;
 702        struct fib_config cfg = {
 703                .fc_protocol = RTPROT_KERNEL,
 704                .fc_type = type,
 705                .fc_dst = dst,
 706                .fc_dst_len = dst_len,
 707                .fc_prefsrc = ifa->ifa_local,
 708                .fc_oif = ifa->ifa_dev->dev->ifindex,
 709                .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
 710                .fc_nlinfo = {
 711                        .nl_net = net,
 712                },
 713        };
 714
 715        if (type == RTN_UNICAST)
 716                tb = fib_new_table(net, RT_TABLE_MAIN);
 717        else
 718                tb = fib_new_table(net, RT_TABLE_LOCAL);
 719
 720        if (tb == NULL)
 721                return;
 722
 723        cfg.fc_table = tb->tb_id;
 724
 725        if (type != RTN_LOCAL)
 726                cfg.fc_scope = RT_SCOPE_LINK;
 727        else
 728                cfg.fc_scope = RT_SCOPE_HOST;
 729
 730        if (cmd == RTM_NEWROUTE)
 731                fib_table_insert(tb, &cfg);
 732        else
 733                fib_table_delete(tb, &cfg);
 734}
 735
 736void fib_add_ifaddr(struct in_ifaddr *ifa)
 737{
 738        struct in_device *in_dev = ifa->ifa_dev;
 739        struct net_device *dev = in_dev->dev;
 740        struct in_ifaddr *prim = ifa;
 741        __be32 mask = ifa->ifa_mask;
 742        __be32 addr = ifa->ifa_local;
 743        __be32 prefix = ifa->ifa_address & mask;
 744
 745        if (ifa->ifa_flags & IFA_F_SECONDARY) {
 746                prim = inet_ifa_byprefix(in_dev, prefix, mask);
 747                if (prim == NULL) {
 748                        pr_warn("%s: bug: prim == NULL\n", __func__);
 749                        return;
 750                }
 751        }
 752
 753        fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
 754
 755        if (!(dev->flags & IFF_UP))
 756                return;
 757
 758        /* Add broadcast address, if it is explicitly assigned. */
 759        if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
 760                fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 761
 762        if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
 763            (prefix != addr || ifa->ifa_prefixlen < 32)) {
 764                fib_magic(RTM_NEWROUTE,
 765                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 766                          prefix, ifa->ifa_prefixlen, prim);
 767
 768                /* Add network specific broadcasts, when it takes a sense */
 769                if (ifa->ifa_prefixlen < 31) {
 770                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
 771                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
 772                                  32, prim);
 773                }
 774        }
 775}
 776
 777/* Delete primary or secondary address.
 778 * Optionally, on secondary address promotion consider the addresses
 779 * from subnet iprim as deleted, even if they are in device list.
 780 * In this case the secondary ifa can be in device list.
 781 */
 782void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
 783{
 784        struct in_device *in_dev = ifa->ifa_dev;
 785        struct net_device *dev = in_dev->dev;
 786        struct in_ifaddr *ifa1;
 787        struct in_ifaddr *prim = ifa, *prim1 = NULL;
 788        __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
 789        __be32 any = ifa->ifa_address & ifa->ifa_mask;
 790#define LOCAL_OK        1
 791#define BRD_OK          2
 792#define BRD0_OK         4
 793#define BRD1_OK         8
 794        unsigned int ok = 0;
 795        int subnet = 0;         /* Primary network */
 796        int gone = 1;           /* Address is missing */
 797        int same_prefsrc = 0;   /* Another primary with same IP */
 798
 799        if (ifa->ifa_flags & IFA_F_SECONDARY) {
 800                prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
 801                if (prim == NULL) {
 802                        pr_warn("%s: bug: prim == NULL\n", __func__);
 803                        return;
 804                }
 805                if (iprim && iprim != prim) {
 806                        pr_warn("%s: bug: iprim != prim\n", __func__);
 807                        return;
 808                }
 809        } else if (!ipv4_is_zeronet(any) &&
 810                   (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
 811                fib_magic(RTM_DELROUTE,
 812                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 813                          any, ifa->ifa_prefixlen, prim);
 814                subnet = 1;
 815        }
 816
 817        /* Deletion is more complicated than add.
 818         * We should take care of not to delete too much :-)
 819         *
 820         * Scan address list to be sure that addresses are really gone.
 821         */
 822
 823        for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
 824                if (ifa1 == ifa) {
 825                        /* promotion, keep the IP */
 826                        gone = 0;
 827                        continue;
 828                }
 829                /* Ignore IFAs from our subnet */
 830                if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
 831                    inet_ifa_match(ifa1->ifa_address, iprim))
 832                        continue;
 833
 834                /* Ignore ifa1 if it uses different primary IP (prefsrc) */
 835                if (ifa1->ifa_flags & IFA_F_SECONDARY) {
 836                        /* Another address from our subnet? */
 837                        if (ifa1->ifa_mask == prim->ifa_mask &&
 838                            inet_ifa_match(ifa1->ifa_address, prim))
 839                                prim1 = prim;
 840                        else {
 841                                /* We reached the secondaries, so
 842                                 * same_prefsrc should be determined.
 843                                 */
 844                                if (!same_prefsrc)
 845                                        continue;
 846                                /* Search new prim1 if ifa1 is not
 847                                 * using the current prim1
 848                                 */
 849                                if (!prim1 ||
 850                                    ifa1->ifa_mask != prim1->ifa_mask ||
 851                                    !inet_ifa_match(ifa1->ifa_address, prim1))
 852                                        prim1 = inet_ifa_byprefix(in_dev,
 853                                                        ifa1->ifa_address,
 854                                                        ifa1->ifa_mask);
 855                                if (!prim1)
 856                                        continue;
 857                                if (prim1->ifa_local != prim->ifa_local)
 858                                        continue;
 859                        }
 860                } else {
 861                        if (prim->ifa_local != ifa1->ifa_local)
 862                                continue;
 863                        prim1 = ifa1;
 864                        if (prim != prim1)
 865                                same_prefsrc = 1;
 866                }
 867                if (ifa->ifa_local == ifa1->ifa_local)
 868                        ok |= LOCAL_OK;
 869                if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
 870                        ok |= BRD_OK;
 871                if (brd == ifa1->ifa_broadcast)
 872                        ok |= BRD1_OK;
 873                if (any == ifa1->ifa_broadcast)
 874                        ok |= BRD0_OK;
 875                /* primary has network specific broadcasts */
 876                if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
 877                        __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
 878                        __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
 879
 880                        if (!ipv4_is_zeronet(any1)) {
 881                                if (ifa->ifa_broadcast == brd1 ||
 882                                    ifa->ifa_broadcast == any1)
 883                                        ok |= BRD_OK;
 884                                if (brd == brd1 || brd == any1)
 885                                        ok |= BRD1_OK;
 886                                if (any == brd1 || any == any1)
 887                                        ok |= BRD0_OK;
 888                        }
 889                }
 890        }
 891
 892        if (!(ok & BRD_OK))
 893                fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 894        if (subnet && ifa->ifa_prefixlen < 31) {
 895                if (!(ok & BRD1_OK))
 896                        fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
 897                if (!(ok & BRD0_OK))
 898                        fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
 899        }
 900        if (!(ok & LOCAL_OK)) {
 901                fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
 902
 903                /* Check, that this local address finally disappeared. */
 904                if (gone &&
 905                    inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) {
 906                        /* And the last, but not the least thing.
 907                         * We must flush stray FIB entries.
 908                         *
 909                         * First of all, we scan fib_info list searching
 910                         * for stray nexthop entries, then ignite fib_flush.
 911                         */
 912                        if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local))
 913                                fib_flush(dev_net(dev));
 914                }
 915        }
 916#undef LOCAL_OK
 917#undef BRD_OK
 918#undef BRD0_OK
 919#undef BRD1_OK
 920}
 921
 922static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
 923{
 924
 925        struct fib_result       res;
 926        struct flowi4           fl4 = {
 927                .flowi4_mark = frn->fl_mark,
 928                .daddr = frn->fl_addr,
 929                .flowi4_tos = frn->fl_tos,
 930                .flowi4_scope = frn->fl_scope,
 931        };
 932
 933        frn->err = -ENOENT;
 934        if (tb) {
 935                local_bh_disable();
 936
 937                frn->tb_id = tb->tb_id;
 938                rcu_read_lock();
 939                frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
 940
 941                if (!frn->err) {
 942                        frn->prefixlen = res.prefixlen;
 943                        frn->nh_sel = res.nh_sel;
 944                        frn->type = res.type;
 945                        frn->scope = res.scope;
 946                }
 947                rcu_read_unlock();
 948                local_bh_enable();
 949        }
 950}
 951
 952static void nl_fib_input(struct sk_buff *skb)
 953{
 954        struct net *net;
 955        struct fib_result_nl *frn;
 956        struct nlmsghdr *nlh;
 957        struct fib_table *tb;
 958        u32 pid;
 959
 960        net = sock_net(skb->sk);
 961        nlh = nlmsg_hdr(skb);
 962        if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
 963            nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn)))
 964                return;
 965
 966        skb = skb_clone(skb, GFP_KERNEL);
 967        if (skb == NULL)
 968                return;
 969        nlh = nlmsg_hdr(skb);
 970
 971        frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
 972        tb = fib_get_table(net, frn->tb_id_in);
 973
 974        nl_fib_lookup(frn, tb);
 975
 976        pid = NETLINK_CB(skb).pid;      /* pid of sending process */
 977        NETLINK_CB(skb).pid = 0;        /* from kernel */
 978        NETLINK_CB(skb).dst_group = 0;  /* unicast */
 979        netlink_unicast(net->ipv4.fibnl, skb, pid, MSG_DONTWAIT);
 980}
 981
 982static int __net_init nl_fib_lookup_init(struct net *net)
 983{
 984        struct sock *sk;
 985        struct netlink_kernel_cfg cfg = {
 986                .input  = nl_fib_input,
 987        };
 988
 989        sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, THIS_MODULE, &cfg);
 990        if (sk == NULL)
 991                return -EAFNOSUPPORT;
 992        net->ipv4.fibnl = sk;
 993        return 0;
 994}
 995
 996static void nl_fib_lookup_exit(struct net *net)
 997{
 998        netlink_kernel_release(net->ipv4.fibnl);
 999        net->ipv4.fibnl = NULL;
1000}
1001
1002static void fib_disable_ip(struct net_device *dev, int force)
1003{
1004        if (fib_sync_down_dev(dev, force))
1005                fib_flush(dev_net(dev));
1006        rt_cache_flush(dev_net(dev));
1007        arp_ifdown(dev);
1008}
1009
1010static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1011{
1012        struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1013        struct net_device *dev = ifa->ifa_dev->dev;
1014        struct net *net = dev_net(dev);
1015
1016        switch (event) {
1017        case NETDEV_UP:
1018                fib_add_ifaddr(ifa);
1019#ifdef CONFIG_IP_ROUTE_MULTIPATH
1020                fib_sync_up(dev);
1021#endif
1022                atomic_inc(&net->ipv4.dev_addr_genid);
1023                rt_cache_flush(dev_net(dev));
1024                break;
1025        case NETDEV_DOWN:
1026                fib_del_ifaddr(ifa, NULL);
1027                atomic_inc(&net->ipv4.dev_addr_genid);
1028                if (ifa->ifa_dev->ifa_list == NULL) {
1029                        /* Last address was deleted from this interface.
1030                         * Disable IP.
1031                         */
1032                        fib_disable_ip(dev, 1);
1033                } else {
1034                        rt_cache_flush(dev_net(dev));
1035                }
1036                break;
1037        }
1038        return NOTIFY_DONE;
1039}
1040
1041static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1042{
1043        struct net_device *dev = ptr;
1044        struct in_device *in_dev = __in_dev_get_rtnl(dev);
1045        struct net *net = dev_net(dev);
1046
1047        if (event == NETDEV_UNREGISTER) {
1048                fib_disable_ip(dev, 2);
1049                rt_flush_dev(dev);
1050                return NOTIFY_DONE;
1051        }
1052
1053        if (!in_dev)
1054                return NOTIFY_DONE;
1055
1056        switch (event) {
1057        case NETDEV_UP:
1058                for_ifa(in_dev) {
1059                        fib_add_ifaddr(ifa);
1060                } endfor_ifa(in_dev);
1061#ifdef CONFIG_IP_ROUTE_MULTIPATH
1062                fib_sync_up(dev);
1063#endif
1064                atomic_inc(&net->ipv4.dev_addr_genid);
1065                rt_cache_flush(dev_net(dev));
1066                break;
1067        case NETDEV_DOWN:
1068                fib_disable_ip(dev, 0);
1069                break;
1070        case NETDEV_CHANGEMTU:
1071        case NETDEV_CHANGE:
1072                rt_cache_flush(dev_net(dev));
1073                break;
1074        case NETDEV_UNREGISTER_BATCH:
1075                break;
1076        }
1077        return NOTIFY_DONE;
1078}
1079
1080static struct notifier_block fib_inetaddr_notifier = {
1081        .notifier_call = fib_inetaddr_event,
1082};
1083
1084static struct notifier_block fib_netdev_notifier = {
1085        .notifier_call = fib_netdev_event,
1086};
1087
1088static int __net_init ip_fib_net_init(struct net *net)
1089{
1090        int err;
1091        size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1092
1093        /* Avoid false sharing : Use at least a full cache line */
1094        size = max_t(size_t, size, L1_CACHE_BYTES);
1095
1096        net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1097        if (net->ipv4.fib_table_hash == NULL)
1098                return -ENOMEM;
1099
1100        err = fib4_rules_init(net);
1101        if (err < 0)
1102                goto fail;
1103        return 0;
1104
1105fail:
1106        kfree(net->ipv4.fib_table_hash);
1107        return err;
1108}
1109
1110static void ip_fib_net_exit(struct net *net)
1111{
1112        unsigned int i;
1113
1114#ifdef CONFIG_IP_MULTIPLE_TABLES
1115        fib4_rules_exit(net);
1116#endif
1117
1118        rtnl_lock();
1119        for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
1120                struct fib_table *tb;
1121                struct hlist_head *head;
1122                struct hlist_node *node, *tmp;
1123
1124                head = &net->ipv4.fib_table_hash[i];
1125                hlist_for_each_entry_safe(tb, node, tmp, head, tb_hlist) {
1126                        hlist_del(node);
1127                        fib_table_flush(tb);
1128                        fib_free_table(tb);
1129                }
1130        }
1131        rtnl_unlock();
1132        kfree(net->ipv4.fib_table_hash);
1133}
1134
1135static int __net_init fib_net_init(struct net *net)
1136{
1137        int error;
1138
1139#ifdef CONFIG_IP_ROUTE_CLASSID
1140        net->ipv4.fib_num_tclassid_users = 0;
1141#endif
1142        error = ip_fib_net_init(net);
1143        if (error < 0)
1144                goto out;
1145        error = nl_fib_lookup_init(net);
1146        if (error < 0)
1147                goto out_nlfl;
1148        error = fib_proc_init(net);
1149        if (error < 0)
1150                goto out_proc;
1151out:
1152        return error;
1153
1154out_proc:
1155        nl_fib_lookup_exit(net);
1156out_nlfl:
1157        ip_fib_net_exit(net);
1158        goto out;
1159}
1160
1161static void __net_exit fib_net_exit(struct net *net)
1162{
1163        fib_proc_exit(net);
1164        nl_fib_lookup_exit(net);
1165        ip_fib_net_exit(net);
1166}
1167
1168static struct pernet_operations fib_net_ops = {
1169        .init = fib_net_init,
1170        .exit = fib_net_exit,
1171};
1172
1173void __init ip_fib_init(void)
1174{
1175        rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL);
1176        rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL);
1177        rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL);
1178
1179        register_pernet_subsys(&fib_net_ops);
1180        register_netdevice_notifier(&fib_netdev_notifier);
1181        register_inetaddr_notifier(&fib_inetaddr_notifier);
1182
1183        fib_trie_init();
1184}
1185
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