net/ipv4/fib_frontend.c

   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
  51 static 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
  69 fail:
  70         kfree(local_table);
  71         return -ENOMEM;
  72 }
  73 #else
  74
  75 struct 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
 112 struct 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
 136 static 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, -1);
 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  */
 158 static 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
 185 unsigned int inet_addr_type(struct net *net, __be32 addr)
 186 {
 187         return __inet_dev_addr_type(net, NULL, addr);
 188 }
 189 EXPORT_SYMBOL(inet_addr_type);
 190
 191 unsigned 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 }
 196 EXPORT_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 = LOOPBACK_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  */
 244 static 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
 306 last_resort:
 307         if (rpf)
 308                 goto e_rpf;
 309         *itag = 0;
 310         return 0;
 311
 312 e_inval:
 313         return -EINVAL;
 314 e_rpf:
 315         return -EXDEV;
 316 }
 317
 318 /* Ignore rp_filter for packets protected by IPsec. */
 319 int 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
 332 static inline __be32 sk_extract_addr(struct sockaddr *addr)
 333 {
 334         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 335 }
 336
 337 static 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
 349 static 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  */
 481 int 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
 524 const 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
 537 static 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;
 604 errout:
 605         return err;
 606 }
 607
 608 static 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);
 626 errout:
 627         return err;
 628 }
 629
 630 static 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);
 648 errout:
 649         return err;
 650 }
 651
 652 static 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;
 681 next:
 682                         e++;
 683                 }
 684         }
 685 out:
 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  */
 698 static 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
 736 void 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  */
 782 void 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
 922 static 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
 952 static 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
 982 static 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
 996 static void nl_fib_lookup_exit(struct net *net)
 997 {
 998         netlink_kernel_release(net->ipv4.fibnl);
 999         net->ipv4.fibnl = NULL;
1000 }
1001
1002 static void fib_disable_ip(struct net_device *dev, int force, int delay)
1003 {
1004         if (fib_sync_down_dev(dev, force))
1005                 fib_flush(dev_net(dev));
1006         rt_cache_flush(dev_net(dev), delay);
1007         arp_ifdown(dev);
1008 }
1009
1010 static 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), -1);
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, 0);
1033                 } else {
1034                         rt_cache_flush(dev_net(dev), -1);
1035                 }
1036                 break;
1037         }
1038         return NOTIFY_DONE;
1039 }
1040
1041 static 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, -1);
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), -1);
1066                 break;
1067         case NETDEV_DOWN:
1068                 fib_disable_ip(dev, 0, 0);
1069                 break;
1070         case NETDEV_CHANGEMTU:
1071         case NETDEV_CHANGE:
1072                 rt_cache_flush(dev_net(dev), 0);
1073                 break;
1074         case NETDEV_UNREGISTER_BATCH:
1075                 break;
1076         }
1077         return NOTIFY_DONE;
1078 }
1079
1080 static struct notifier_block fib_inetaddr_notifier = {
1081         .notifier_call = fib_inetaddr_event,
1082 };
1083
1084 static struct notifier_block fib_netdev_notifier = {
1085         .notifier_call = fib_netdev_event,
1086 };
1087
1088 static 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
1105 fail:
1106         kfree(net->ipv4.fib_table_hash);
1107         return err;
1108 }
1109
1110 static 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
1135 static 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;
1151 out:
1152         return error;
1153
1154 out_proc:
1155         nl_fib_lookup_exit(net);
1156 out_nlfl:
1157         ip_fib_net_exit(net);
1158         goto out;
1159 }
1160
1161 static 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
1168 static struct pernet_operations fib_net_ops = {
1169         .init = fib_net_init,
1170         .exit = fib_net_exit,
1171 };
1172
1173 void __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 }