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  * Version:     $Id: fib_frontend.c,v 1.26 2001/10/31 21:55:54 davem Exp $
   9  *
  10  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  */
  17
  18 #include <linux/config.h>
  19 #include <linux/module.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/system.h>
  22 #include <linux/bitops.h>
  23 #include <linux/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/sched.h>
  26 #include <linux/mm.h>
  27 #include <linux/string.h>
  28 #include <linux/socket.h>
  29 #include <linux/sockios.h>
  30 #include <linux/errno.h>
  31 #include <linux/in.h>
  32 #include <linux/inet.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/if_arp.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/netlink.h>
  37 #include <linux/init.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/icmp.h>
  45 #include <net/arp.h>
  46 #include <net/ip_fib.h>
  47
  48 #define FFprint(a...) printk(KERN_DEBUG a)
  49
  50 #ifndef CONFIG_IP_MULTIPLE_TABLES
  51
  52 #define RT_TABLE_MIN RT_TABLE_MAIN
  53
  54 struct fib_table *ip_fib_local_table;
  55 struct fib_table *ip_fib_main_table;
  56
  57 #else
  58
  59 #define RT_TABLE_MIN 1
  60
  61 struct fib_table *fib_tables[RT_TABLE_MAX+1];
  62
  63 struct fib_table *__fib_new_table(int id)
  64 {
  65         struct fib_table *tb;
  66
  67         tb = fib_hash_init(id);
  68         if (!tb)
  69                 return NULL;
  70         fib_tables[id] = tb;
  71         return tb;
  72 }
  73
  74
  75 #endif /* CONFIG_IP_MULTIPLE_TABLES */
  76
  77
  78 static void fib_flush(void)
  79 {
  80         int flushed = 0;
  81 #ifdef CONFIG_IP_MULTIPLE_TABLES
  82         struct fib_table *tb;
  83         int id;
  84
  85         for (id = RT_TABLE_MAX; id>0; id--) {
  86                 if ((tb = fib_get_table(id))==NULL)
  87                         continue;
  88                 flushed += tb->tb_flush(tb);
  89         }
  90 #else /* CONFIG_IP_MULTIPLE_TABLES */
  91         flushed += ip_fib_main_table->tb_flush(ip_fib_main_table);
  92         flushed += ip_fib_local_table->tb_flush(ip_fib_local_table);
  93 #endif /* CONFIG_IP_MULTIPLE_TABLES */
  94
  95         if (flushed)
  96                 rt_cache_flush(-1);
  97 }
  98
  99 /*
 100  *      Find the first device with a given source address.
 101  */
 102
 103 struct net_device * ip_dev_find(u32 addr)
 104 {
 105         struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
 106         struct fib_result res;
 107         struct net_device *dev = NULL;
 108
 109 #ifdef CONFIG_IP_MULTIPLE_TABLES
 110         res.r = NULL;
 111 #endif
 112
 113         if (!ip_fib_local_table ||
 114             ip_fib_local_table->tb_lookup(ip_fib_local_table, &fl, &res))
 115                 return NULL;
 116         if (res.type != RTN_LOCAL)
 117                 goto out;
 118         dev = FIB_RES_DEV(res);
 119
 120         if (dev)
 121                 dev_hold(dev);
 122 out:
 123         fib_res_put(&res);
 124         return dev;
 125 }
 126
 127 unsigned inet_addr_type(u32 addr)
 128 {
 129         struct flowi            fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
 130         struct fib_result       res;
 131         unsigned ret = RTN_BROADCAST;
 132
 133         if (ZERONET(addr) || BADCLASS(addr))
 134                 return RTN_BROADCAST;
 135         if (MULTICAST(addr))
 136                 return RTN_MULTICAST;
 137
 138 #ifdef CONFIG_IP_MULTIPLE_TABLES
 139         res.r = NULL;
 140 #endif
 141
 142         if (ip_fib_local_table) {
 143                 ret = RTN_UNICAST;
 144                 if (!ip_fib_local_table->tb_lookup(ip_fib_local_table,
 145                                                    &fl, &res)) {
 146                         ret = res.type;
 147                         fib_res_put(&res);
 148                 }
 149         }
 150         return ret;
 151 }
 152
 153 /* Given (packet source, input interface) and optional (dst, oif, tos):
 154    - (main) check, that source is valid i.e. not broadcast or our local
 155      address.
 156    - figure out what "logical" interface this packet arrived
 157      and calculate "specific destination" address.
 158    - check, that packet arrived from expected physical interface.
 159  */
 160
 161 int fib_validate_source(u32 src, u32 dst, u8 tos, int oif,
 162                         struct net_device *dev, u32 *spec_dst, u32 *itag)
 163 {
 164         struct in_device *in_dev;
 165         struct flowi fl = { .nl_u = { .ip4_u =
 166                                       { .daddr = src,
 167                                         .saddr = dst,
 168                                         .tos = tos } },
 169                             .iif = oif };
 170         struct fib_result res;
 171         int no_addr, rpf;
 172         int ret;
 173
 174         no_addr = rpf = 0;
 175         rcu_read_lock();
 176         in_dev = __in_dev_get(dev);
 177         if (in_dev) {
 178                 no_addr = in_dev->ifa_list == NULL;
 179                 rpf = IN_DEV_RPFILTER(in_dev);
 180         }
 181         rcu_read_unlock();
 182
 183         if (in_dev == NULL)
 184                 goto e_inval;
 185
 186         if (fib_lookup(&fl, &res))
 187                 goto last_resort;
 188         if (res.type != RTN_UNICAST)
 189                 goto e_inval_res;
 190         *spec_dst = FIB_RES_PREFSRC(res);
 191         fib_combine_itag(itag, &res);
 192 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 193         if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1)
 194 #else
 195         if (FIB_RES_DEV(res) == dev)
 196 #endif
 197         {
 198                 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 199                 fib_res_put(&res);
 200                 return ret;
 201         }
 202         fib_res_put(&res);
 203         if (no_addr)
 204                 goto last_resort;
 205         if (rpf)
 206                 goto e_inval;
 207         fl.oif = dev->ifindex;
 208
 209         ret = 0;
 210         if (fib_lookup(&fl, &res) == 0) {
 211                 if (res.type == RTN_UNICAST) {
 212                         *spec_dst = FIB_RES_PREFSRC(res);
 213                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 214                 }
 215                 fib_res_put(&res);
 216         }
 217         return ret;
 218
 219 last_resort:
 220         if (rpf)
 221                 goto e_inval;
 222         *spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
 223         *itag = 0;
 224         return 0;
 225
 226 e_inval_res:
 227         fib_res_put(&res);
 228 e_inval:
 229         return -EINVAL;
 230 }
 231
 232 #ifndef CONFIG_IP_NOSIOCRT
 233
 234 /*
 235  *      Handle IP routing ioctl calls. These are used to manipulate the routing tables
 236  */
 237
 238 int ip_rt_ioctl(unsigned int cmd, void __user *arg)
 239 {
 240         int err;
 241         struct kern_rta rta;
 242         struct rtentry  r;
 243         struct {
 244                 struct nlmsghdr nlh;
 245                 struct rtmsg    rtm;
 246         } req;
 247
 248         switch (cmd) {
 249         case SIOCADDRT:         /* Add a route */
 250         case SIOCDELRT:         /* Delete a route */
 251                 if (!capable(CAP_NET_ADMIN))
 252                         return -EPERM;
 253                 if (copy_from_user(&r, arg, sizeof(struct rtentry)))
 254                         return -EFAULT;
 255                 rtnl_lock();
 256                 err = fib_convert_rtentry(cmd, &req.nlh, &req.rtm, &rta, &r);
 257                 if (err == 0) {
 258                         if (cmd == SIOCDELRT) {
 259                                 struct fib_table *tb = fib_get_table(req.rtm.rtm_table);
 260                                 err = -ESRCH;
 261                                 if (tb)
 262                                         err = tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL);
 263                         } else {
 264                                 struct fib_table *tb = fib_new_table(req.rtm.rtm_table);
 265                                 err = -ENOBUFS;
 266                                 if (tb)
 267                                         err = tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL);
 268                         }
 269                         if (rta.rta_mx)
 270                                 kfree(rta.rta_mx);
 271                 }
 272                 rtnl_unlock();
 273                 return err;
 274         }
 275         return -EINVAL;
 276 }
 277
 278 #else
 279
 280 int ip_rt_ioctl(unsigned int cmd, void *arg)
 281 {
 282         return -EINVAL;
 283 }
 284
 285 #endif
 286
 287 static int inet_check_attr(struct rtmsg *r, struct rtattr **rta)
 288 {
 289         int i;
 290
 291         for (i=1; i<=RTA_MAX; i++) {
 292                 struct rtattr *attr = rta[i-1];
 293                 if (attr) {
 294                         if (RTA_PAYLOAD(attr) < 4)
 295                                 return -EINVAL;
 296                         if (i != RTA_MULTIPATH && i != RTA_METRICS)
 297                                 rta[i-1] = (struct rtattr*)RTA_DATA(attr);
 298                 }
 299         }
 300         return 0;
 301 }
 302
 303 int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 304 {
 305         struct fib_table * tb;
 306         struct rtattr **rta = arg;
 307         struct rtmsg *r = NLMSG_DATA(nlh);
 308
 309         if (inet_check_attr(r, rta))
 310                 return -EINVAL;
 311
 312         tb = fib_get_table(r->rtm_table);
 313         if (tb)
 314                 return tb->tb_delete(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb));
 315         return -ESRCH;
 316 }
 317
 318 int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 319 {
 320         struct fib_table * tb;
 321         struct rtattr **rta = arg;
 322         struct rtmsg *r = NLMSG_DATA(nlh);
 323
 324         if (inet_check_attr(r, rta))
 325                 return -EINVAL;
 326
 327         tb = fib_new_table(r->rtm_table);
 328         if (tb)
 329                 return tb->tb_insert(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb));
 330         return -ENOBUFS;
 331 }
 332
 333 int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 334 {
 335         int t;
 336         int s_t;
 337         struct fib_table *tb;
 338
 339         if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&
 340             ((struct rtmsg*)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)
 341                 return ip_rt_dump(skb, cb);
 342
 343         s_t = cb->args[0];
 344         if (s_t == 0)
 345                 s_t = cb->args[0] = RT_TABLE_MIN;
 346
 347         for (t=s_t; t<=RT_TABLE_MAX; t++) {
 348                 if (t < s_t) continue;
 349                 if (t > s_t)
 350                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 351                 if ((tb = fib_get_table(t))==NULL)
 352                         continue;
 353                 if (tb->tb_dump(tb, skb, cb) < 0)
 354                         break;
 355         }
 356
 357         cb->args[0] = t;
 358
 359         return skb->len;
 360 }
 361
 362 /* Prepare and feed intra-kernel routing request.
 363    Really, it should be netlink message, but :-( netlink
 364    can be not configured, so that we feed it directly
 365    to fib engine. It is legal, because all events occur
 366    only when netlink is already locked.
 367  */
 368
 369 static void fib_magic(int cmd, int type, u32 dst, int dst_len, struct in_ifaddr *ifa)
 370 {
 371         struct fib_table * tb;
 372         struct {
 373                 struct nlmsghdr nlh;
 374                 struct rtmsg    rtm;
 375         } req;
 376         struct kern_rta rta;
 377
 378         memset(&req.rtm, 0, sizeof(req.rtm));
 379         memset(&rta, 0, sizeof(rta));
 380
 381         if (type == RTN_UNICAST)
 382                 tb = fib_new_table(RT_TABLE_MAIN);
 383         else
 384                 tb = fib_new_table(RT_TABLE_LOCAL);
 385
 386         if (tb == NULL)
 387                 return;
 388
 389         req.nlh.nlmsg_len = sizeof(req);
 390         req.nlh.nlmsg_type = cmd;
 391         req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_APPEND;
 392         req.nlh.nlmsg_pid = 0;
 393         req.nlh.nlmsg_seq = 0;
 394
 395         req.rtm.rtm_dst_len = dst_len;
 396         req.rtm.rtm_table = tb->tb_id;
 397         req.rtm.rtm_protocol = RTPROT_KERNEL;
 398         req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
 399         req.rtm.rtm_type = type;
 400
 401         rta.rta_dst = &dst;
 402         rta.rta_prefsrc = &ifa->ifa_local;
 403         rta.rta_oif = &ifa->ifa_dev->dev->ifindex;
 404
 405         if (cmd == RTM_NEWROUTE)
 406                 tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL);
 407         else
 408                 tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL);
 409 }
 410
 411 static void fib_add_ifaddr(struct in_ifaddr *ifa)
 412 {
 413         struct in_device *in_dev = ifa->ifa_dev;
 414         struct net_device *dev = in_dev->dev;
 415         struct in_ifaddr *prim = ifa;
 416         u32 mask = ifa->ifa_mask;
 417         u32 addr = ifa->ifa_local;
 418         u32 prefix = ifa->ifa_address&mask;
 419
 420         if (ifa->ifa_flags&IFA_F_SECONDARY) {
 421                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
 422                 if (prim == NULL) {
 423                         printk(KERN_DEBUG "fib_add_ifaddr: bug: prim == NULL\n");
 424                         return;
 425                 }
 426         }
 427
 428         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
 429
 430         if (!(dev->flags&IFF_UP))
 431                 return;
 432
 433         /* Add broadcast address, if it is explicitly assigned. */
 434         if (ifa->ifa_broadcast && ifa->ifa_broadcast != 0xFFFFFFFF)
 435                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 436
 437         if (!ZERONET(prefix) && !(ifa->ifa_flags&IFA_F_SECONDARY) &&
 438             (prefix != addr || ifa->ifa_prefixlen < 32)) {
 439                 fib_magic(RTM_NEWROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
 440                           RTN_UNICAST, prefix, ifa->ifa_prefixlen, prim);
 441
 442                 /* Add network specific broadcasts, when it takes a sense */
 443                 if (ifa->ifa_prefixlen < 31) {
 444                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
 445                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix|~mask, 32, prim);
 446                 }
 447         }
 448 }
 449
 450 static void fib_del_ifaddr(struct in_ifaddr *ifa)
 451 {
 452         struct in_device *in_dev = ifa->ifa_dev;
 453         struct net_device *dev = in_dev->dev;
 454         struct in_ifaddr *ifa1;
 455         struct in_ifaddr *prim = ifa;
 456         u32 brd = ifa->ifa_address|~ifa->ifa_mask;
 457         u32 any = ifa->ifa_address&ifa->ifa_mask;
 458 #define LOCAL_OK        1
 459 #define BRD_OK          2
 460 #define BRD0_OK         4
 461 #define BRD1_OK         8
 462         unsigned ok = 0;
 463
 464         if (!(ifa->ifa_flags&IFA_F_SECONDARY))
 465                 fib_magic(RTM_DELROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
 466                           RTN_UNICAST, any, ifa->ifa_prefixlen, prim);
 467         else {
 468                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
 469                 if (prim == NULL) {
 470                         printk(KERN_DEBUG "fib_del_ifaddr: bug: prim == NULL\n");
 471                         return;
 472                 }
 473         }
 474
 475         /* Deletion is more complicated than add.
 476            We should take care of not to delete too much :-)
 477
 478            Scan address list to be sure that addresses are really gone.
 479          */
 480
 481         for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
 482                 if (ifa->ifa_local == ifa1->ifa_local)
 483                         ok |= LOCAL_OK;
 484                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
 485                         ok |= BRD_OK;
 486                 if (brd == ifa1->ifa_broadcast)
 487                         ok |= BRD1_OK;
 488                 if (any == ifa1->ifa_broadcast)
 489                         ok |= BRD0_OK;
 490         }
 491
 492         if (!(ok&BRD_OK))
 493                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 494         if (!(ok&BRD1_OK))
 495                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
 496         if (!(ok&BRD0_OK))
 497                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
 498         if (!(ok&LOCAL_OK)) {
 499                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
 500
 501                 /* Check, that this local address finally disappeared. */
 502                 if (inet_addr_type(ifa->ifa_local) != RTN_LOCAL) {
 503                         /* And the last, but not the least thing.
 504                            We must flush stray FIB entries.
 505
 506                            First of all, we scan fib_info list searching
 507                            for stray nexthop entries, then ignite fib_flush.
 508                         */
 509                         if (fib_sync_down(ifa->ifa_local, NULL, 0))
 510                                 fib_flush();
 511                 }
 512         }
 513 #undef LOCAL_OK
 514 #undef BRD_OK
 515 #undef BRD0_OK
 516 #undef BRD1_OK
 517 }
 518
 519 static void fib_disable_ip(struct net_device *dev, int force)
 520 {
 521         if (fib_sync_down(0, dev, force))
 522                 fib_flush();
 523         rt_cache_flush(0);
 524         arp_ifdown(dev);
 525 }
 526
 527 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
 528 {
 529         struct in_ifaddr *ifa = (struct in_ifaddr*)ptr;
 530
 531         switch (event) {
 532         case NETDEV_UP:
 533                 fib_add_ifaddr(ifa);
 534 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 535                 fib_sync_up(ifa->ifa_dev->dev);
 536 #endif
 537                 rt_cache_flush(-1);
 538                 break;
 539         case NETDEV_DOWN:
 540                 fib_del_ifaddr(ifa);
 541                 if (ifa->ifa_dev && ifa->ifa_dev->ifa_list == NULL) {
 542                         /* Last address was deleted from this interface.
 543                            Disable IP.
 544                          */
 545                         fib_disable_ip(ifa->ifa_dev->dev, 1);
 546                 } else {
 547                         rt_cache_flush(-1);
 548                 }
 549                 break;
 550         }
 551         return NOTIFY_DONE;
 552 }
 553
 554 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
 555 {
 556         struct net_device *dev = ptr;
 557         struct in_device *in_dev = __in_dev_get(dev);
 558
 559         if (event == NETDEV_UNREGISTER) {
 560                 fib_disable_ip(dev, 2);
 561                 return NOTIFY_DONE;
 562         }
 563
 564         if (!in_dev)
 565                 return NOTIFY_DONE;
 566
 567         switch (event) {
 568         case NETDEV_UP:
 569                 for_ifa(in_dev) {
 570                         fib_add_ifaddr(ifa);
 571                 } endfor_ifa(in_dev);
 572 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 573                 fib_sync_up(dev);
 574 #endif
 575                 rt_cache_flush(-1);
 576                 break;
 577         case NETDEV_DOWN:
 578                 fib_disable_ip(dev, 0);
 579                 break;
 580         case NETDEV_CHANGEMTU:
 581         case NETDEV_CHANGE:
 582                 rt_cache_flush(0);
 583                 break;
 584         }
 585         return NOTIFY_DONE;
 586 }
 587
 588 static struct notifier_block fib_inetaddr_notifier = {
 589         .notifier_call =fib_inetaddr_event,
 590 };
 591
 592 static struct notifier_block fib_netdev_notifier = {
 593         .notifier_call =fib_netdev_event,
 594 };
 595
 596 void __init ip_fib_init(void)
 597 {
 598 #ifndef CONFIG_IP_MULTIPLE_TABLES
 599         ip_fib_local_table = fib_hash_init(RT_TABLE_LOCAL);
 600         ip_fib_main_table  = fib_hash_init(RT_TABLE_MAIN);
 601 #else
 602         fib_rules_init();
 603 #endif
 604
 605         register_netdevice_notifier(&fib_netdev_notifier);
 606         register_inetaddr_notifier(&fib_inetaddr_notifier);
 607 }
 608
 609 EXPORT_SYMBOL(inet_addr_type);
 610 EXPORT_SYMBOL(ip_dev_find);
 611 EXPORT_SYMBOL(ip_rt_ioctl);