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 } 440