i386/linux/linux-2.3.21/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 1.14 1999/08/31 07:03:29 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 = { NULL, ATOMIC_INIT(2), 0x7FFF, RT_TABLE_DEFAULT, RTN_UNICAST, };
  80 static struct fib_rule main_rule = { &default_rule, ATOMIC_INIT(2), 0x7FFE, RT_TABLE_MAIN, RTN_UNICAST, };
  81 static struct fib_rule local_rule = { &main_rule, ATOMIC_INIT(2), 0, RT_TABLE_LOCAL, RTN_UNICAST, };
  82
  83 static struct fib_rule *fib_rules = &local_rule;
  84 static rwlock_t fib_rules_lock = RW_LOCK_UNLOCKED;
  85
  86 int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
  87 {
  88         struct rtattr **rta = arg;
  89         struct rtmsg *rtm = NLMSG_DATA(nlh);
  90         struct fib_rule *r, **rp;
  91         int err = -ESRCH;
  92
  93         for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {
  94                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&
  95                     rtm->rtm_src_len == r->r_src_len &&
  96                     rtm->rtm_dst_len == r->r_dst_len &&
  97                     (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) &&
  98                     rtm->rtm_tos == r->r_tos &&
  99 #ifdef CONFIG_IP_ROUTE_FWMARK
 100                     (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
 101 #endif
 102                     (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
 103                     (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
 104                     (!rta[RTA_IIF-1] || strcmp(RTA_DATA(rta[RTA_IIF-1]), r->r_ifname) == 0) &&
 105                     (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
 106                         err = -EPERM;
 107                         if (r == &local_rule)
 108                                 break;
 109
 110                         write_lock_bh(&fib_rules_lock);
 111                         *rp = r->r_next;
 112                         r->r_dead = 1;
 113                         write_unlock_bh(&fib_rules_lock);
 114                         fib_rule_put(r);
 115                         err = 0;
 116                         break;
 117                 }
 118         }
 119         return err;
 120 }
 121
 122 /* Allocate new unique table id */
 123
 124 static struct fib_table *fib_empty_table(void)
 125 {
 126         int id;
 127
 128         for (id = 1; id <= RT_TABLE_MAX; id++)
 129                 if (fib_tables[id] == NULL)
 130                         return __fib_new_table(id);
 131         return NULL;
 132 }
 133
 134 void fib_rule_put(struct fib_rule *r)
 135 {
 136         if (atomic_dec_and_test(&r->r_clntref)) {
 137                 if (r->r_dead)
 138                         kfree(r);
 139                 else
 140                         printk("Freeing alive rule %p\n", r);
 141         }
 142 }
 143
 144 int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 145 {
 146         struct rtattr **rta = arg;
 147         struct rtmsg *rtm = NLMSG_DATA(nlh);
 148         struct fib_rule *r, *new_r, **rp;
 149         unsigned char table_id;
 150
 151         if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
 152             (rtm->rtm_tos & ~IPTOS_TOS_MASK))
 153                 return -EINVAL;
 154
 155         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 156                 return -EINVAL;
 157
 158         table_id = rtm->rtm_table;
 159         if (table_id == RT_TABLE_UNSPEC) {
 160                 struct fib_table *table;
 161                 if (rtm->rtm_type == RTN_UNICAST || rtm->rtm_type == RTN_NAT) {
 162                         if ((table = fib_empty_table()) == NULL)
 163                                 return -ENOBUFS;
 164                         table_id = table->tb_id;
 165                 }
 166         }
 167
 168         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 169         if (!new_r)
 170                 return -ENOMEM;
 171         memset(new_r, 0, sizeof(*new_r));
 172         if (rta[RTA_SRC-1])
 173                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);
 174         if (rta[RTA_DST-1])
 175                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4);
 176         if (rta[RTA_GATEWAY-1])
 177                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4);
 178         new_r->r_src_len = rtm->rtm_src_len;
 179         new_r->r_dst_len = rtm->rtm_dst_len;
 180         new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len);
 181         new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len);
 182         new_r->r_tos = rtm->rtm_tos;
 183 #ifdef CONFIG_IP_ROUTE_FWMARK
 184         if (rta[RTA_PROTOINFO-1])
 185                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 186 #endif
 187         new_r->r_action = rtm->rtm_type;
 188         new_r->r_flags = rtm->rtm_flags;
 189         if (rta[RTA_PRIORITY-1])
 190                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 191         new_r->r_table = table_id;
 192         if (rta[RTA_IIF-1]) {
 193                 struct net_device *dev;
 194                 memcpy(new_r->r_ifname, RTA_DATA(rta[RTA_IIF-1]), IFNAMSIZ);
 195                 new_r->r_ifname[IFNAMSIZ-1] = 0;
 196                 new_r->r_ifindex = -1;
 197                 dev = __dev_get_by_name(new_r->r_ifname);
 198                 if (dev)
 199                         new_r->r_ifindex = dev->ifindex;
 200         }
 201 #ifdef CONFIG_NET_CLS_ROUTE
 202         if (rta[RTA_FLOW-1])
 203                 memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);
 204 #endif
 205
 206         rp = &fib_rules;
 207         if (!new_r->r_preference) {
 208                 r = fib_rules;
 209                 if (r && (r = r->r_next) != NULL) {
 210                         rp = &fib_rules->r_next;
 211                         if (r->r_preference)
 212                                 new_r->r_preference = r->r_preference - 1;
 213                 }
 214         }
 215
 216         while ( (r = *rp) != NULL ) {
 217                 if (r->r_preference > new_r->r_preference)
 218                         break;
 219                 rp = &r->r_next;
 220         }
 221
 222         new_r->r_next = r;
 223         atomic_inc(&new_r->r_clntref);
 224         write_lock_bh(&fib_rules_lock);
 225         *rp = new_r;
 226         write_unlock_bh(&fib_rules_lock);
 227         return 0;
 228 }
 229
 230 u32 fib_rules_map_destination(u32 daddr, struct fib_result *res)
 231 {
 232         u32 mask = inet_make_mask(res->prefixlen);
 233         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 234 }
 235
 236 u32 fib_rules_policy(u32 saddr, struct fib_result *res, unsigned *flags)
 237 {
 238         struct fib_rule *r = res->r;
 239
 240         if (r->r_action == RTN_NAT) {
 241                 int addrtype = inet_addr_type(r->r_srcmap);
 242
 243                 if (addrtype == RTN_NAT) {
 244                         /* Packet is from  translated source; remember it */
 245                         saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
 246                         *flags |= RTCF_SNAT;
 247                 } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
 248                         /* Packet is from masqueraded source; remember it */
 249                         saddr = r->r_srcmap;
 250                         *flags |= RTCF_MASQ;
 251                 }
 252         }
 253         return saddr;
 254 }
 255
 256 #ifdef CONFIG_NET_CLS_ROUTE
 257 u32 fib_rules_tclass(struct fib_result *res)
 258 {
 259         if (res->r)
 260                 return res->r->r_tclassid;
 261         return 0;
 262 }
 263 #endif
 264
 265
 266 static void fib_rules_detach(struct net_device *dev)
 267 {
 268         struct fib_rule *r;
 269
 270         for (r=fib_rules; r; r=r->r_next) {
 271                 if (r->r_ifindex == dev->ifindex) {
 272                         write_lock_bh(&fib_rules_lock);
 273                         r->r_ifindex = -1;
 274                         write_unlock_bh(&fib_rules_lock);
 275                 }
 276         }
 277 }
 278
 279 static void fib_rules_attach(struct net_device *dev)
 280 {
 281         struct fib_rule *r;
 282
 283         for (r=fib_rules; r; r=r->r_next) {
 284                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
 285                         write_lock_bh(&fib_rules_lock);
 286                         r->r_ifindex = dev->ifindex;
 287                         write_unlock_bh(&fib_rules_lock);
 288                 }
 289         }
 290 }
 291
 292 int fib_lookup(const struct rt_key *key, struct fib_result *res)
 293 {
 294         int err;
 295         struct fib_rule *r, *policy;
 296         struct fib_table *tb;
 297
 298         u32 daddr = key->dst;
 299         u32 saddr = key->src;
 300
 301 FRprintk("Lookup: %08x <- %08x ", key->dst, key->src);
 302         read_lock(&fib_rules_lock);
 303         for (r = fib_rules; r; r=r->r_next) {
 304                 if (((saddr^r->r_src) & r->r_srcmask) ||
 305                     ((daddr^r->r_dst) & r->r_dstmask) ||
 306 #ifdef CONFIG_IP_ROUTE_TOS
 307                     (r->r_tos && r->r_tos != key->tos) ||
 308 #endif
 309 #ifdef CONFIG_IP_ROUTE_FWMARK
 310                     (r->r_fwmark && r->r_fwmark != key->fwmark) ||
 311 #endif
 312                     (r->r_ifindex && r->r_ifindex != key->iif))
 313                         continue;
 314
 315 FRprintk("tb %d r %d ", r->r_table, r->r_action);
 316                 switch (r->r_action) {
 317                 case RTN_UNICAST:
 318                 case RTN_NAT:
 319                         policy = r;
 320                         break;
 321                 case RTN_UNREACHABLE:
 322                         read_unlock(&fib_rules_lock);
 323                         return -ENETUNREACH;
 324                 default:
 325                 case RTN_BLACKHOLE:
 326                         read_unlock(&fib_rules_lock);
 327                         return -EINVAL;
 328                 case RTN_PROHIBIT:
 329                         read_unlock(&fib_rules_lock);
 330                         return -EACCES;
 331                 }
 332
 333                 if ((tb = fib_get_table(r->r_table)) == NULL)
 334                         continue;
 335                 err = tb->tb_lookup(tb, key, res);
 336                 if (err == 0) {
 337                         res->r = policy;
 338                         if (policy)
 339                                 atomic_inc(&policy->r_clntref);
 340                         read_unlock(&fib_rules_lock);
 341                         return 0;
 342                 }
 343                 if (err < 0 && err != -EAGAIN) {
 344                         read_unlock(&fib_rules_lock);
 345                         return err;
 346                 }
 347         }
 348 FRprintk("FAILURE\n");
 349         read_unlock(&fib_rules_lock);
 350         return -ENETUNREACH;
 351 }
 352
 353 void fib_select_default(const struct rt_key *key, struct fib_result *res)
 354 {
 355         if (res->r && res->r->r_action == RTN_UNICAST &&
 356             FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
 357                 struct fib_table *tb;
 358                 if ((tb = fib_get_table(res->r->r_table)) != NULL)
 359                         tb->tb_select_default(tb, key, res);
 360         }
 361 }
 362
 363 static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 364 {
 365         struct net_device *dev = ptr;
 366
 367         if (event == NETDEV_UNREGISTER)
 368                 fib_rules_detach(dev);
 369         else if (event == NETDEV_REGISTER)
 370                 fib_rules_attach(dev);
 371         return NOTIFY_DONE;
 372 }
 373
 374
 375 struct notifier_block fib_rules_notifier = {
 376         fib_rules_event,
 377         NULL,
 378         0
 379 };
 380
 381 #ifdef CONFIG_RTNETLINK
 382
 383 extern __inline__ int inet_fill_rule(struct sk_buff *skb,
 384                                      struct fib_rule *r,
 385                                      struct netlink_callback *cb)
 386 {
 387         struct rtmsg *rtm;
 388         struct nlmsghdr  *nlh;
 389         unsigned char    *b = skb->tail;
 390
 391         nlh = NLMSG_PUT(skb, NETLINK_CREDS(cb->skb)->pid, cb->nlh->nlmsg_seq, RTM_NEWRULE, sizeof(*rtm));
 392         rtm = NLMSG_DATA(nlh);
 393         rtm->rtm_family = AF_INET;
 394         rtm->rtm_dst_len = r->r_dst_len;
 395         rtm->rtm_src_len = r->r_src_len;
 396         rtm->rtm_tos = r->r_tos;
 397 #ifdef CONFIG_IP_ROUTE_FWMARK
 398         if (r->r_fwmark)
 399                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 400 #endif
 401         rtm->rtm_table = r->r_table;
 402         rtm->rtm_protocol = 0;
 403         rtm->rtm_scope = 0;
 404         rtm->rtm_type = r->r_action;
 405         rtm->rtm_flags = r->r_flags;
 406
 407         if (r->r_dst_len)
 408                 RTA_PUT(skb, RTA_DST, 4, &r->r_dst);
 409         if (r->r_src_len)
 410                 RTA_PUT(skb, RTA_SRC, 4, &r->r_src);
 411         if (r->r_ifname[0])
 412                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 413         if (r->r_preference)
 414                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 415         if (r->r_srcmap)
 416                 RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap);
 417 #ifdef CONFIG_NET_CLS_ROUTE
 418         if (r->r_tclassid)
 419                 RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid);
 420 #endif
 421         nlh->nlmsg_len = skb->tail - b;
 422         return skb->len;
 423
 424 nlmsg_failure:
 425 rtattr_failure:
 426         skb_put(skb, b - skb->tail);
 427         return -1;
 428 }
 429
 430 int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 431 {
 432         int idx;
 433         int s_idx = cb->args[0];
 434         struct fib_rule *r;
 435
 436         read_lock(&fib_rules_lock);
 437         for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {
 438                 if (idx < s_idx)
 439                         continue;
 440                 if (inet_fill_rule(skb, r, cb) < 0)
 441                         break;
 442         }
 443         read_unlock(&fib_rules_lock);
 444         cb->args[0] = idx;
 445
 446         return skb->len;
 447 }
 448
 449 #endif /* CONFIG_RTNETLINK */
 450
 451 void __init fib_rules_init(void)
 452 {
 453         register_netdevice_notifier(&fib_rules_notifier);
 454 }