kernel/linux/net/ipv4/fib_rules.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: policy rules.
   7  *
   8  * Version:     $Id: fib_rules.c,v 1.17 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  * Fixes:
  18  *              Rani Assaf      :       local_rule cannot be deleted
  19  *              Marc Boucher    :       routing by fwmark
  20  */
  21
  22 #include <linux/config.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/system.h>
  25 #include <asm/bitops.h>
  26 #include <linux/types.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/mm.h>
  30 #include <linux/string.h>
  31 #include <linux/socket.h>
  32 #include <linux/sockios.h>
  33 #include <linux/errno.h>
  34 #include <linux/in.h>
  35 #include <linux/inet.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/if_arp.h>
  38 #include <linux/proc_fs.h>
  39 #include <linux/skbuff.h>
  40 #include <linux/netlink.h>
  41 #include <linux/init.h>
  42
  43 #include <net/ip.h>
  44 #include <net/protocol.h>
  45 #include <net/route.h>
  46 #include <net/tcp.h>
  47 #include <net/sock.h>
  48 #include <net/ip_fib.h>
  49
  50 #define FRprintk(a...)
  51
  52 struct fib_rule
  53 {
  54         struct fib_rule *r_next;
  55         atomic_t        r_clntref;
  56         u32             r_preference;
  57         unsigned char   r_table;
  58         unsigned char   r_action;
  59         unsigned char   r_dst_len;
  60         unsigned char   r_src_len;
  61         u32             r_src;
  62         u32             r_srcmask;
  63         u32             r_dst;
  64         u32             r_dstmask;
  65         u32             r_srcmap;
  66         u8              r_flags;
  67         u8              r_tos;
  68 #ifdef CONFIG_IP_ROUTE_FWMARK
  69         u32             r_fwmark;
  70 #endif
  71         int             r_ifindex;
  72 #ifdef CONFIG_NET_CLS_ROUTE
  73         __u32           r_tclassid;
  74 #endif
  75         char            r_ifname[IFNAMSIZ];
  76         int             r_dead;
  77 };
  78
  79 static struct fib_rule default_rule = {
  80         .r_clntref =    ATOMIC_INIT(2),
  81         .r_preference = 0x7FFF,
  82         .r_table =      RT_TABLE_DEFAULT,
  83         .r_action =     RTN_UNICAST,
  84 };
  85
  86 static struct fib_rule main_rule = {
  87         .r_next =       &default_rule,
  88         .r_clntref =    ATOMIC_INIT(2),
  89         .r_preference = 0x7FFE,
  90         .r_table =      RT_TABLE_MAIN,
  91         .r_action =     RTN_UNICAST,
  92 };
  93
  94 static struct fib_rule local_rule = {
  95         .r_next =       &main_rule,
  96         .r_clntref =    ATOMIC_INIT(2),
  97         .r_table =      RT_TABLE_LOCAL,
  98         .r_action =     RTN_UNICAST,
  99 };
 100
 101 static struct fib_rule *fib_rules = &local_rule;
 102 static rwlock_t fib_rules_lock = RW_LOCK_UNLOCKED;
 103
 104 int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 105 {
 106         struct rtattr **rta = arg;
 107         struct rtmsg *rtm = NLMSG_DATA(nlh);
 108         struct fib_rule *r, **rp;
 109         int err = -ESRCH;
 110
 111         for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {
 112                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&
 113                     rtm->rtm_src_len == r->r_src_len &&
 114                     rtm->rtm_dst_len == r->r_dst_len &&
 115                     (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) &&
 116                     rtm->rtm_tos == r->r_tos &&
 117 #ifdef CONFIG_IP_ROUTE_FWMARK
 118                     (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
 119 #endif
 120                     (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
 121                     (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
 122                     (!rta[RTA_IIF-1] || strcmp(RTA_DATA(rta[RTA_IIF-1]), r->r_ifname) == 0) &&
 123                     (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
 124                         err = -EPERM;
 125                         if (r == &local_rule)
 126                                 break;
 127
 128                         write_lock_bh(&fib_rules_lock);
 129                         *rp = r->r_next;
 130                         r->r_dead = 1;
 131                         write_unlock_bh(&fib_rules_lock);
 132                         fib_rule_put(r);
 133                         err = 0;
 134                         break;
 135                 }
 136         }
 137         return err;
 138 }
 139
 140 /* Allocate new unique table id */
 141
 142 static struct fib_table *fib_empty_table(void)
 143 {
 144         int id;
 145
 146         for (id = 1; id <= RT_TABLE_MAX; id++)
 147                 if (fib_tables[id] == NULL)
 148                         return __fib_new_table(id);
 149         return NULL;
 150 }
 151
 152 void fib_rule_put(struct fib_rule *r)
 153 {
 154         if (atomic_dec_and_test(&r->r_clntref)) {
 155                 if (r->r_dead)
 156                         kfree(r);
 157                 else
 158                         printk("Freeing alive rule %p\n", r);
 159         }
 160 }
 161
 162 int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 163 {
 164         struct rtattr **rta = arg;
 165         struct rtmsg *rtm = NLMSG_DATA(nlh);
 166         struct fib_rule *r, *new_r, **rp;
 167         unsigned char table_id;
 168
 169         if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
 170             (rtm->rtm_tos & ~IPTOS_TOS_MASK))
 171                 return -EINVAL;
 172
 173         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 174                 return -EINVAL;
 175
 176         table_id = rtm->rtm_table;
 177         if (table_id == RT_TABLE_UNSPEC) {
 178                 struct fib_table *table;
 179                 if (rtm->rtm_type == RTN_UNICAST || rtm->rtm_type == RTN_NAT) {
 180                         if ((table = fib_empty_table()) == NULL)
 181                                 return -ENOBUFS;
 182                         table_id = table->tb_id;
 183                 }
 184         }
 185
 186         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 187         if (!new_r)
 188                 return -ENOMEM;
 189         memset(new_r, 0, sizeof(*new_r));
 190         if (rta[RTA_SRC-1])
 191                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);
 192         if (rta[RTA_DST-1])
 193                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4);
 194         if (rta[RTA_GATEWAY-1])
 195                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4);
 196         new_r->r_src_len = rtm->rtm_src_len;
 197         new_r->r_dst_len = rtm->rtm_dst_len;
 198         new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len);
 199         new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len);
 200         new_r->r_tos = rtm->rtm_tos;
 201 #ifdef CONFIG_IP_ROUTE_FWMARK
 202         if (rta[RTA_PROTOINFO-1])
 203                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 204 #endif
 205         new_r->r_action = rtm->rtm_type;
 206         new_r->r_flags = rtm->rtm_flags;
 207         if (rta[RTA_PRIORITY-1])
 208                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 209         new_r->r_table = table_id;
 210         if (rta[RTA_IIF-1]) {
 211                 struct net_device *dev;
 212                 memcpy(new_r->r_ifname, RTA_DATA(rta[RTA_IIF-1]), IFNAMSIZ);
 213                 new_r->r_ifname[IFNAMSIZ-1] = 0;
 214                 new_r->r_ifindex = -1;
 215                 dev = __dev_get_by_name(new_r->r_ifname);
 216                 if (dev)
 217                         new_r->r_ifindex = dev->ifindex;
 218         }
 219 #ifdef CONFIG_NET_CLS_ROUTE
 220         if (rta[RTA_FLOW-1])
 221                 memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);
 222 #endif
 223
 224         rp = &fib_rules;
 225         if (!new_r->r_preference) {
 226                 r = fib_rules;
 227                 if (r && (r = r->r_next) != NULL) {
 228                         rp = &fib_rules->r_next;
 229                         if (r->r_preference)
 230                                 new_r->r_preference = r->r_preference - 1;
 231                 }
 232         }
 233
 234         while ( (r = *rp) != NULL ) {
 235                 if (r->r_preference > new_r->r_preference)
 236                         break;
 237                 rp = &r->r_next;
 238         }
 239
 240         new_r->r_next = r;
 241         atomic_inc(&new_r->r_clntref);
 242         write_lock_bh(&fib_rules_lock);
 243         *rp = new_r;
 244         write_unlock_bh(&fib_rules_lock);
 245         return 0;
 246 }
 247
 248 u32 fib_rules_map_destination(u32 daddr, struct fib_result *res)
 249 {
 250         u32 mask = inet_make_mask(res->prefixlen);
 251         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 252 }
 253
 254 u32 fib_rules_policy(u32 saddr, struct fib_result *res, unsigned *flags)
 255 {
 256         struct fib_rule *r = res->r;
 257
 258         if (r->r_action == RTN_NAT) {
 259                 int addrtype = inet_addr_type(r->r_srcmap);
 260
 261                 if (addrtype == RTN_NAT) {
 262                         /* Packet is from  translated source; remember it */
 263                         saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
 264                         *flags |= RTCF_SNAT;
 265                 } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
 266                         /* Packet is from masqueraded source; remember it */
 267                         saddr = r->r_srcmap;
 268                         *flags |= RTCF_MASQ;
 269                 }
 270         }
 271         return saddr;
 272 }
 273
 274 #ifdef CONFIG_NET_CLS_ROUTE
 275 u32 fib_rules_tclass(struct fib_result *res)
 276 {
 277         if (res->r)
 278                 return res->r->r_tclassid;
 279         return 0;
 280 }
 281 #endif
 282
 283
 284 static void fib_rules_detach(struct net_device *dev)
 285 {
 286         struct fib_rule *r;
 287
 288         for (r=fib_rules; r; r=r->r_next) {
 289                 if (r->r_ifindex == dev->ifindex) {
 290                         write_lock_bh(&fib_rules_lock);
 291                         r->r_ifindex = -1;
 292                         write_unlock_bh(&fib_rules_lock);
 293                 }
 294         }
 295 }
 296
 297 static void fib_rules_attach(struct net_device *dev)
 298 {
 299         struct fib_rule *r;
 300
 301         for (r=fib_rules; r; r=r->r_next) {
 302                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
 303                         write_lock_bh(&fib_rules_lock);
 304                         r->r_ifindex = dev->ifindex;
 305                         write_unlock_bh(&fib_rules_lock);
 306                 }
 307         }
 308 }
 309
 310 int fib_lookup(const struct flowi *flp, struct fib_result *res)
 311 {
 312         int err;
 313         struct fib_rule *r, *policy;
 314         struct fib_table *tb;
 315
 316         u32 daddr = flp->fl4_dst;
 317         u32 saddr = flp->fl4_src;
 318
 319 FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",
 320         NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src));
 321         read_lock(&fib_rules_lock);
 322         for (r = fib_rules; r; r=r->r_next) {
 323                 if (((saddr^r->r_src) & r->r_srcmask) ||
 324                     ((daddr^r->r_dst) & r->r_dstmask) ||
 325 #ifdef CONFIG_IP_ROUTE_TOS
 326                     (r->r_tos && r->r_tos != flp->fl4_tos) ||
 327 #endif
 328 #ifdef CONFIG_IP_ROUTE_FWMARK
 329                     (r->r_fwmark && r->r_fwmark != flp->fl4_fwmark) ||
 330 #endif
 331                     (r->r_ifindex && r->r_ifindex != flp->iif))
 332                         continue;
 333
 334 FRprintk("tb %d r %d ", r->r_table, r->r_action);
 335                 switch (r->r_action) {
 336                 case RTN_UNICAST:
 337                 case RTN_NAT:
 338                         policy = r;
 339                         break;
 340                 case RTN_UNREACHABLE:
 341                         read_unlock(&fib_rules_lock);
 342                         return -ENETUNREACH;
 343                 default:
 344                 case RTN_BLACKHOLE:
 345                         read_unlock(&fib_rules_lock);
 346                         return -EINVAL;
 347                 case RTN_PROHIBIT:
 348                         read_unlock(&fib_rules_lock);
 349                         return -EACCES;
 350                 }
 351
 352                 if ((tb = fib_get_table(r->r_table)) == NULL)
 353                         continue;
 354                 err = tb->tb_lookup(tb, flp, res);
 355                 if (err == 0) {
 356                         res->r = policy;
 357                         if (policy)
 358                                 atomic_inc(&policy->r_clntref);
 359                         read_unlock(&fib_rules_lock);
 360                         return 0;
 361                 }
 362                 if (err < 0 && err != -EAGAIN) {
 363                         read_unlock(&fib_rules_lock);
 364                         return err;
 365                 }
 366         }
 367 FRprintk("FAILURE\n");
 368         read_unlock(&fib_rules_lock);
 369         return -ENETUNREACH;
 370 }
 371
 372 void fib_select_default(const struct flowi *flp, struct fib_result *res)
 373 {
 374         if (res->r && res->r->r_action == RTN_UNICAST &&
 375             FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
 376                 struct fib_table *tb;
 377                 if ((tb = fib_get_table(res->r->r_table)) != NULL)
 378                         tb->tb_select_default(tb, flp, res);
 379         }
 380 }
 381
 382 static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 383 {
 384         struct net_device *dev = ptr;
 385
 386         if (event == NETDEV_UNREGISTER)
 387                 fib_rules_detach(dev);
 388         else if (event == NETDEV_REGISTER)
 389                 fib_rules_attach(dev);
 390         return NOTIFY_DONE;
 391 }
 392
 393
 394 struct notifier_block fib_rules_notifier = {
 395         .notifier_call =fib_rules_event,
 396 };
 397
 398 static __inline__ int inet_fill_rule(struct sk_buff *skb,
 399                                      struct fib_rule *r,
 400                                      struct netlink_callback *cb)
 401 {
 402         struct rtmsg *rtm;
 403         struct nlmsghdr  *nlh;
 404         unsigned char    *b = skb->tail;
 405
 406         nlh = NLMSG_PUT(skb, NETLINK_CREDS(cb->skb)->pid, cb->nlh->nlmsg_seq, RTM_NEWRULE, sizeof(*rtm));
 407         rtm = NLMSG_DATA(nlh);
 408         rtm->rtm_family = AF_INET;
 409         rtm->rtm_dst_len = r->r_dst_len;
 410         rtm->rtm_src_len = r->r_src_len;
 411         rtm->rtm_tos = r->r_tos;
 412 #ifdef CONFIG_IP_ROUTE_FWMARK
 413         if (r->r_fwmark)
 414                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 415 #endif
 416         rtm->rtm_table = r->r_table;
 417         rtm->rtm_protocol = 0;
 418         rtm->rtm_scope = 0;
 419         rtm->rtm_type = r->r_action;
 420         rtm->rtm_flags = r->r_flags;
 421
 422         if (r->r_dst_len)
 423                 RTA_PUT(skb, RTA_DST, 4, &r->r_dst);
 424         if (r->r_src_len)
 425                 RTA_PUT(skb, RTA_SRC, 4, &r->r_src);
 426         if (r->r_ifname[0])
 427                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 428         if (r->r_preference)
 429                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 430         if (r->r_srcmap)
 431                 RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap);
 432 #ifdef CONFIG_NET_CLS_ROUTE
 433         if (r->r_tclassid)
 434                 RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid);
 435 #endif
 436         nlh->nlmsg_len = skb->tail - b;
 437         return skb->len;
 438
 439 nlmsg_failure:
 440 rtattr_failure:
 441         skb_trim(skb, b - skb->data);
 442         return -1;
 443 }
 444
 445 int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 446 {
 447         int idx;
 448         int s_idx = cb->args[0];
 449         struct fib_rule *r;
 450
 451         read_lock(&fib_rules_lock);
 452         for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {
 453                 if (idx < s_idx)
 454                         continue;
 455                 if (inet_fill_rule(skb, r, cb) < 0)
 456                         break;
 457         }
 458         read_unlock(&fib_rules_lock);
 459         cb->args[0] = idx;
 460
 461         return skb->len;
 462 }
 463
 464 void __init fib_rules_init(void)
 465 {
 466         register_netdevice_notifier(&fib_rules_notifier);
 467 }