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   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              IPv4 Forwarding Information Base: 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 <linux/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/inetdevice.h>
  37 #include <linux/netdevice.h>
  38 #include <linux/if_arp.h>
  39 #include <linux/proc_fs.h>
  40 #include <linux/skbuff.h>
  41 #include <linux/netlink.h>
  42 #include <linux/init.h>
  43
  44 #include <net/ip.h>
  45 #include <net/protocol.h>
  46 #include <net/route.h>
  47 #include <net/tcp.h>
  48 #include <net/sock.h>
  49 #include <net/ip_fib.h>
  50
  51 #define FRprintk(a...)
  52
  53 struct fib_rule
  54 {
  55         struct fib_rule *r_next;
  56         atomic_t        r_clntref;
  57         u32             r_preference;
  58         unsigned char   r_table;
  59         unsigned char   r_action;
  60         unsigned char   r_dst_len;
  61         unsigned char   r_src_len;
  62         u32             r_src;
  63         u32             r_srcmask;
  64         u32             r_dst;
  65         u32             r_dstmask;
  66         u32             r_srcmap;
  67         u8              r_flags;
  68         u8              r_tos;
  69 #ifdef CONFIG_IP_ROUTE_FWMARK
  70         u32             r_fwmark;
  71 #endif
  72         int             r_ifindex;
  73 #ifdef CONFIG_NET_CLS_ROUTE
  74         __u32           r_tclassid;
  75 #endif
  76         char            r_ifname[IFNAMSIZ];
  77         int             r_dead;
  78 };
  79
  80 static struct fib_rule default_rule = {
  81         .r_clntref =    ATOMIC_INIT(2),
  82         .r_preference = 0x7FFF,
  83         .r_table =      RT_TABLE_DEFAULT,
  84         .r_action =     RTN_UNICAST,
  85 };
  86
  87 static struct fib_rule main_rule = {
  88         .r_next =       &default_rule,
  89         .r_clntref =    ATOMIC_INIT(2),
  90         .r_preference = 0x7FFE,
  91         .r_table =      RT_TABLE_MAIN,
  92         .r_action =     RTN_UNICAST,
  93 };
  94
  95 static struct fib_rule local_rule = {
  96         .r_next =       &main_rule,
  97         .r_clntref =    ATOMIC_INIT(2),
  98         .r_table =      RT_TABLE_LOCAL,
  99         .r_action =     RTN_UNICAST,
 100 };
 101
 102 static struct fib_rule *fib_rules = &local_rule;
 103 static DEFINE_RWLOCK(fib_rules_lock);
 104
 105 int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 106 {
 107         struct rtattr **rta = arg;
 108         struct rtmsg *rtm = NLMSG_DATA(nlh);
 109         struct fib_rule *r, **rp;
 110         int err = -ESRCH;
 111
 112         for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {
 113                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&
 114                     rtm->rtm_src_len == r->r_src_len &&
 115                     rtm->rtm_dst_len == r->r_dst_len &&
 116                     (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) &&
 117                     rtm->rtm_tos == r->r_tos &&
 118 #ifdef CONFIG_IP_ROUTE_FWMARK
 119                     (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
 120 #endif
 121                     (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
 122                     (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
 123                     (!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
 124                     (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
 125                         err = -EPERM;
 126                         if (r == &local_rule)
 127                                 break;
 128
 129                         write_lock_bh(&fib_rules_lock);
 130                         *rp = r->r_next;
 131                         r->r_dead = 1;
 132                         write_unlock_bh(&fib_rules_lock);
 133                         fib_rule_put(r);
 134                         err = 0;
 135                         break;
 136                 }
 137         }
 138         return err;
 139 }
 140
 141 /* Allocate new unique table id */
 142
 143 static struct fib_table *fib_empty_table(void)
 144 {
 145         int id;
 146
 147         for (id = 1; id <= RT_TABLE_MAX; id++)
 148                 if (fib_tables[id] == NULL)
 149                         return __fib_new_table(id);
 150         return NULL;
 151 }
 152
 153 void fib_rule_put(struct fib_rule *r)
 154 {
 155         if (atomic_dec_and_test(&r->r_clntref)) {
 156                 if (r->r_dead)
 157                         kfree(r);
 158                 else
 159                         printk("Freeing alive rule %p\n", r);
 160         }
 161 }
 162
 163 int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 164 {
 165         struct rtattr **rta = arg;
 166         struct rtmsg *rtm = NLMSG_DATA(nlh);
 167         struct fib_rule *r, *new_r, **rp;
 168         unsigned char table_id;
 169
 170         if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
 171             (rtm->rtm_tos & ~IPTOS_TOS_MASK))
 172                 return -EINVAL;
 173
 174         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 175                 return -EINVAL;
 176
 177         table_id = rtm->rtm_table;
 178         if (table_id == RT_TABLE_UNSPEC) {
 179                 struct fib_table *table;
 180                 if (rtm->rtm_type == RTN_UNICAST) {
 181                         if ((table = fib_empty_table()) == NULL)
 182                                 return -ENOBUFS;
 183                         table_id = table->tb_id;
 184                 }
 185         }
 186
 187         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 188         if (!new_r)
 189                 return -ENOMEM;
 190         memset(new_r, 0, sizeof(*new_r));
 191         if (rta[RTA_SRC-1])
 192                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);
 193         if (rta[RTA_DST-1])
 194                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4);
 195         if (rta[RTA_GATEWAY-1])
 196                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4);
 197         new_r->r_src_len = rtm->rtm_src_len;
 198         new_r->r_dst_len = rtm->rtm_dst_len;
 199         new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len);
 200         new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len);
 201         new_r->r_tos = rtm->rtm_tos;
 202 #ifdef CONFIG_IP_ROUTE_FWMARK
 203         if (rta[RTA_PROTOINFO-1])
 204                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 205 #endif
 206         new_r->r_action = rtm->rtm_type;
 207         new_r->r_flags = rtm->rtm_flags;
 208         if (rta[RTA_PRIORITY-1])
 209                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 210         new_r->r_table = table_id;
 211         if (rta[RTA_IIF-1]) {
 212                 struct net_device *dev;
 213                 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
 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 #ifdef CONFIG_NET_CLS_ROUTE
 249 u32 fib_rules_tclass(struct fib_result *res)
 250 {
 251         if (res->r)
 252                 return res->r->r_tclassid;
 253         return 0;
 254 }
 255 #endif
 256
 257
 258 static void fib_rules_detach(struct net_device *dev)
 259 {
 260         struct fib_rule *r;
 261
 262         for (r=fib_rules; r; r=r->r_next) {
 263                 if (r->r_ifindex == dev->ifindex) {
 264                         write_lock_bh(&fib_rules_lock);
 265                         r->r_ifindex = -1;
 266                         write_unlock_bh(&fib_rules_lock);
 267                 }
 268         }
 269 }
 270
 271 static void fib_rules_attach(struct net_device *dev)
 272 {
 273         struct fib_rule *r;
 274
 275         for (r=fib_rules; r; r=r->r_next) {
 276                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
 277                         write_lock_bh(&fib_rules_lock);
 278                         r->r_ifindex = dev->ifindex;
 279                         write_unlock_bh(&fib_rules_lock);
 280                 }
 281         }
 282 }
 283
 284 int fib_lookup(const struct flowi *flp, struct fib_result *res)
 285 {
 286         int err;
 287         struct fib_rule *r, *policy;
 288         struct fib_table *tb;
 289
 290         u32 daddr = flp->fl4_dst;
 291         u32 saddr = flp->fl4_src;
 292
 293 FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",
 294         NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src));
 295         read_lock(&fib_rules_lock);
 296         for (r = fib_rules; r; r=r->r_next) {
 297                 if (((saddr^r->r_src) & r->r_srcmask) ||
 298                     ((daddr^r->r_dst) & r->r_dstmask) ||
 299                     (r->r_tos && r->r_tos != flp->fl4_tos) ||
 300 #ifdef CONFIG_IP_ROUTE_FWMARK
 301                     (r->r_fwmark && r->r_fwmark != flp->fl4_fwmark) ||
 302 #endif
 303                     (r->r_ifindex && r->r_ifindex != flp->iif))
 304                         continue;
 305
 306 FRprintk("tb %d r %d ", r->r_table, r->r_action);
 307                 switch (r->r_action) {
 308                 case RTN_UNICAST:
 309                         policy = r;
 310                         break;
 311                 case RTN_UNREACHABLE:
 312                         read_unlock(&fib_rules_lock);
 313                         return -ENETUNREACH;
 314                 default:
 315                 case RTN_BLACKHOLE:
 316                         read_unlock(&fib_rules_lock);
 317                         return -EINVAL;
 318                 case RTN_PROHIBIT:
 319                         read_unlock(&fib_rules_lock);
 320                         return -EACCES;
 321                 }
 322
 323                 if ((tb = fib_get_table(r->r_table)) == NULL)
 324                         continue;
 325                 err = tb->tb_lookup(tb, flp, res);
 326                 if (err == 0) {
 327                         res->r = policy;
 328                         if (policy)
 329                                 atomic_inc(&policy->r_clntref);
 330                         read_unlock(&fib_rules_lock);
 331                         return 0;
 332                 }
 333                 if (err < 0 && err != -EAGAIN) {
 334                         read_unlock(&fib_rules_lock);
 335                         return err;
 336                 }
 337         }
 338 FRprintk("FAILURE\n");
 339         read_unlock(&fib_rules_lock);
 340         return -ENETUNREACH;
 341 }
 342
 343 void fib_select_default(const struct flowi *flp, struct fib_result *res)
 344 {
 345         if (res->r && res->r->r_action == RTN_UNICAST &&
 346             FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
 347                 struct fib_table *tb;
 348                 if ((tb = fib_get_table(res->r->r_table)) != NULL)
 349                         tb->tb_select_default(tb, flp, res);
 350         }
 351 }
 352
 353 static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 354 {
 355         struct net_device *dev = ptr;
 356
 357         if (event == NETDEV_UNREGISTER)
 358                 fib_rules_detach(dev);
 359         else if (event == NETDEV_REGISTER)
 360                 fib_rules_attach(dev);
 361         return NOTIFY_DONE;
 362 }
 363
 364
 365 static struct notifier_block fib_rules_notifier = {
 366         .notifier_call =fib_rules_event,
 367 };
 368
 369 static __inline__ int inet_fill_rule(struct sk_buff *skb,
 370                                      struct fib_rule *r,
 371                                      struct netlink_callback *cb,
 372                                      unsigned int flags)
 373 {
 374         struct rtmsg *rtm;
 375         struct nlmsghdr  *nlh;
 376         unsigned char    *b = skb->tail;
 377
 378         nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
 379         rtm = NLMSG_DATA(nlh);
 380         rtm->rtm_family = AF_INET;
 381         rtm->rtm_dst_len = r->r_dst_len;
 382         rtm->rtm_src_len = r->r_src_len;
 383         rtm->rtm_tos = r->r_tos;
 384 #ifdef CONFIG_IP_ROUTE_FWMARK
 385         if (r->r_fwmark)
 386                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 387 #endif
 388         rtm->rtm_table = r->r_table;
 389         rtm->rtm_protocol = 0;
 390         rtm->rtm_scope = 0;
 391         rtm->rtm_type = r->r_action;
 392         rtm->rtm_flags = r->r_flags;
 393
 394         if (r->r_dst_len)
 395                 RTA_PUT(skb, RTA_DST, 4, &r->r_dst);
 396         if (r->r_src_len)
 397                 RTA_PUT(skb, RTA_SRC, 4, &r->r_src);
 398         if (r->r_ifname[0])
 399                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 400         if (r->r_preference)
 401                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 402         if (r->r_srcmap)
 403                 RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap);
 404 #ifdef CONFIG_NET_CLS_ROUTE
 405         if (r->r_tclassid)
 406                 RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid);
 407 #endif
 408         nlh->nlmsg_len = skb->tail - b;
 409         return skb->len;
 410
 411 nlmsg_failure:
 412 rtattr_failure:
 413         skb_trim(skb, b - skb->data);
 414         return -1;
 415 }
 416
 417 int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 418 {
 419         int idx;
 420         int s_idx = cb->args[0];
 421         struct fib_rule *r;
 422
 423         read_lock(&fib_rules_lock);
 424         for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {
 425                 if (idx < s_idx)
 426                         continue;
 427                 if (inet_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
 428                         break;
 429         }
 430         read_unlock(&fib_rules_lock);
 431         cb->args[0] = idx;
 432
 433         return skb->len;
 434 }
 435
 436 void __init fib_rules_init(void)
 437 {
 438         register_netdevice_notifier(&fib_rules_notifier);
 439 }