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 <asm/uaccess.h> 23 #include <asm/system.h> 24 #include <linux/bitops.h> 25 #include <linux/types.h> 26 #include <linux/kernel.h> 27 #include <linux/sched.h> 28 #include <linux/mm.h> 29 #include <linux/string.h> 30 #include <linux/socket.h> 31 #include <linux/sockios.h> 32 #include <linux/errno.h> 33 #include <linux/in.h> 34 #include <linux/inet.h> 35 #include <linux/inetdevice.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 #include <linux/list.h> 43 #include <linux/rcupdate.h> 44 45 #include <net/ip.h> 46 #include <net/protocol.h> 47 #include <net/route.h> 48 #include <net/tcp.h> 49 #include <net/sock.h> 50 #include <net/ip_fib.h> 51 52 #define FRprintk(a...) 53 54 struct fib_rule 55 { 56 struct hlist_node hlist; 57 atomic_t r_clntref; 58 u32 r_preference; 59 unsigned char r_table; 60 unsigned char r_action; 61 unsigned char r_dst_len; 62 unsigned char r_src_len; 63 u32 r_src; 64 u32 r_srcmask; 65 u32 r_dst; 66 u32 r_dstmask; 67 u32 r_srcmap; 68 u8 r_flags; 69 u8 r_tos; 70 #ifdef CONFIG_IP_ROUTE_FWMARK 71 u32 r_fwmark; 72 #endif 73 int r_ifindex; 74 #ifdef CONFIG_NET_CLS_ROUTE 75 __u32 r_tclassid; 76 #endif 77 char r_ifname[IFNAMSIZ]; 78 int r_dead; 79 struct rcu_head rcu; 80 }; 81 82 static struct fib_rule default_rule = { 83 .r_clntref = ATOMIC_INIT(2), 84 .r_preference = 0x7FFF, 85 .r_table = RT_TABLE_DEFAULT, 86 .r_action = RTN_UNICAST, 87 }; 88 89 static struct fib_rule main_rule = { 90 .r_clntref = ATOMIC_INIT(2), 91 .r_preference = 0x7FFE, 92 .r_table = RT_TABLE_MAIN, 93 .r_action = RTN_UNICAST, 94 }; 95 96 static struct fib_rule local_rule = { 97 .r_clntref = ATOMIC_INIT(2), 98 .r_table = RT_TABLE_LOCAL, 99 .r_action = RTN_UNICAST, 100 }; 101 102 static struct hlist_head fib_rules; 103 104 /* writer func called from netlink -- rtnl_sem hold*/ 105 106 static void rtmsg_rule(int, struct fib_rule *); 107 108 int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 109 { 110 struct rtattr **rta = arg; 111 struct rtmsg *rtm = NLMSG_DATA(nlh); 112 struct fib_rule *r; 113 struct hlist_node *node; 114 int err = -ESRCH; 115 116 hlist_for_each_entry(r, node, &fib_rules, hlist) { 117 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) && 118 rtm->rtm_src_len == r->r_src_len && 119 rtm->rtm_dst_len == r->r_dst_len && 120 (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) && 121 rtm->rtm_tos == r->r_tos && 122 #ifdef CONFIG_IP_ROUTE_FWMARK 123 (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) && 124 #endif 125 (!rtm->rtm_type || rtm->rtm_type == r->r_action) && 126 (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) && 127 (!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) && 128 (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) { 129 err = -EPERM; 130 if (r == &local_rule) 131 break; 132 133 hlist_del_rcu(&r->hlist); 134 r->r_dead = 1; 135 rtmsg_rule(RTM_DELRULE, r); 136 fib_rule_put(r); 137 err = 0; 138 break; 139 } 140 } 141 return err; 142 } 143 144 /* Allocate new unique table id */ 145 146 static struct fib_table *fib_empty_table(void) 147 { 148 int id; 149 150 for (id = 1; id <= RT_TABLE_MAX; id++) 151 if (fib_tables[id] == NULL) 152 return __fib_new_table(id); 153 return NULL; 154 } 155 156 static inline void fib_rule_put_rcu(struct rcu_head *head) 157 { 158 struct fib_rule *r = container_of(head, struct fib_rule, rcu); 159 kfree(r); 160 } 161 162 void fib_rule_put(struct fib_rule *r) 163 { 164 if (atomic_dec_and_test(&r->r_clntref)) { 165 if (r->r_dead) 166 call_rcu(&r->rcu, fib_rule_put_rcu); 167 else 168 printk("Freeing alive rule %p\n", r); 169 } 170 } 171 172 /* writer func called from netlink -- rtnl_sem hold*/ 173 174 int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 175 { 176 struct rtattr **rta = arg; 177 struct rtmsg *rtm = NLMSG_DATA(nlh); 178 struct fib_rule *r, *new_r, *last = NULL; 179 struct hlist_node *node = NULL; 180 unsigned char table_id; 181 182 if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 || 183 (rtm->rtm_tos & ~IPTOS_TOS_MASK)) 184 return -EINVAL; 185 186 if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ) 187 return -EINVAL; 188 189 table_id = rtm->rtm_table; 190 if (table_id == RT_TABLE_UNSPEC) { 191 struct fib_table *table; 192 if (rtm->rtm_type == RTN_UNICAST) { 193 if ((table = fib_empty_table()) == NULL) 194 return -ENOBUFS; 195 table_id = table->tb_id; 196 } 197 } 198 199 new_r = kzalloc(sizeof(*new_r), GFP_KERNEL); 200 if (!new_r) 201 return -ENOMEM; 202 203 if (rta[RTA_SRC-1]) 204 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4); 205 if (rta[RTA_DST-1]) 206 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4); 207 if (rta[RTA_GATEWAY-1]) 208 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4); 209 new_r->r_src_len = rtm->rtm_src_len; 210 new_r->r_dst_len = rtm->rtm_dst_len; 211 new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len); 212 new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len); 213 new_r->r_tos = rtm->rtm_tos; 214 #ifdef CONFIG_IP_ROUTE_FWMARK 215 if (rta[RTA_PROTOINFO-1]) 216 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4); 217 #endif 218 new_r->r_action = rtm->rtm_type; 219 new_r->r_flags = rtm->rtm_flags; 220 if (rta[RTA_PRIORITY-1]) 221 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4); 222 new_r->r_table = table_id; 223 if (rta[RTA_IIF-1]) { 224 struct net_device *dev; 225 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ); 226 new_r->r_ifindex = -1; 227 dev = __dev_get_by_name(new_r->r_ifname); 228 if (dev) 229 new_r->r_ifindex = dev->ifindex; 230 } 231 #ifdef CONFIG_NET_CLS_ROUTE 232 if (rta[RTA_FLOW-1]) 233 memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4); 234 #endif 235 r = container_of(fib_rules.first, struct fib_rule, hlist); 236 237 if (!new_r->r_preference) { 238 if (r && r->hlist.next != NULL) { 239 r = container_of(r->hlist.next, struct fib_rule, hlist); 240 if (r->r_preference) 241 new_r->r_preference = r->r_preference - 1; 242 } 243 } 244 245 hlist_for_each_entry(r, node, &fib_rules, hlist) { 246 if (r->r_preference > new_r->r_preference) 247 break; 248 last = r; 249 } 250 atomic_inc(&new_r->r_clntref); 251 252 if (last) 253 hlist_add_after_rcu(&last->hlist, &new_r->hlist); 254 else 255 hlist_add_before_rcu(&new_r->hlist, &r->hlist); 256 257 rtmsg_rule(RTM_NEWRULE, new_r); 258 return 0; 259 } 260 261 #ifdef CONFIG_NET_CLS_ROUTE 262 u32 fib_rules_tclass(struct fib_result *res) 263 { 264 if (res->r) 265 return res->r->r_tclassid; 266 return 0; 267 } 268 #endif 269 270 /* callers should hold rtnl semaphore */ 271 272 static void fib_rules_detach(struct net_device *dev) 273 { 274 struct hlist_node *node; 275 struct fib_rule *r; 276 277 hlist_for_each_entry(r, node, &fib_rules, hlist) { 278 if (r->r_ifindex == dev->ifindex) 279 r->r_ifindex = -1; 280 281 } 282 } 283 284 /* callers should hold rtnl semaphore */ 285 286 static void fib_rules_attach(struct net_device *dev) 287 { 288 struct hlist_node *node; 289 struct fib_rule *r; 290 291 hlist_for_each_entry(r, node, &fib_rules, hlist) { 292 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) 293 r->r_ifindex = dev->ifindex; 294 } 295 } 296 297 int fib_lookup(const struct flowi *flp, struct fib_result *res) 298 { 299 int err; 300 struct fib_rule *r, *policy; 301 struct fib_table *tb; 302 struct hlist_node *node; 303 304 u32 daddr = flp->fl4_dst; 305 u32 saddr = flp->fl4_src; 306 307 FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ", 308 NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src)); 309 310 rcu_read_lock(); 311 312 hlist_for_each_entry_rcu(r, node, &fib_rules, hlist) { 313 if (((saddr^r->r_src) & r->r_srcmask) || 314 ((daddr^r->r_dst) & r->r_dstmask) || 315 (r->r_tos && r->r_tos != flp->fl4_tos) || 316 #ifdef CONFIG_IP_ROUTE_FWMARK 317 (r->r_fwmark && r->r_fwmark != flp->fl4_fwmark) || 318 #endif 319 (r->r_ifindex && r->r_ifindex != flp->iif)) 320 continue; 321 322 FRprintk("tb %d r %d ", r->r_table, r->r_action); 323 switch (r->r_action) { 324 case RTN_UNICAST: 325 policy = r; 326 break; 327 case RTN_UNREACHABLE: 328 rcu_read_unlock(); 329 return -ENETUNREACH; 330 default: 331 case RTN_BLACKHOLE: 332 rcu_read_unlock(); 333 return -EINVAL; 334 case RTN_PROHIBIT: 335 rcu_read_unlock(); 336 return -EACCES; 337 } 338 339 if ((tb = fib_get_table(r->r_table)) == NULL) 340 continue; 341 err = tb->tb_lookup(tb, flp, res); 342 if (err == 0) { 343 res->r = policy; 344 if (policy) 345 atomic_inc(&policy->r_clntref); 346 rcu_read_unlock(); 347 return 0; 348 } 349 if (err < 0 && err != -EAGAIN) { 350 rcu_read_unlock(); 351 return err; 352 } 353 } 354 FRprintk("FAILURE\n"); 355 rcu_read_unlock(); 356 return -ENETUNREACH; 357 } 358 359 void fib_select_default(const struct flowi *flp, struct fib_result *res) 360 { 361 if (res->r && res->r->r_action == RTN_UNICAST && 362 FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) { 363 struct fib_table *tb; 364 if ((tb = fib_get_table(res->r->r_table)) != NULL) 365 tb->tb_select_default(tb, flp, res); 366 } 367 } 368 369 static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr) 370 { 371 struct net_device *dev = ptr; 372 373 if (event == NETDEV_UNREGISTER) 374 fib_rules_detach(dev); 375 else if (event == NETDEV_REGISTER) 376 fib_rules_attach(dev); 377 return NOTIFY_DONE; 378 } 379 380 381 static struct notifier_block fib_rules_notifier = { 382 .notifier_call =fib_rules_event, 383 }; 384 385 static __inline__ int inet_fill_rule(struct sk_buff *skb, 386 struct fib_rule *r, 387 u32 pid, u32 seq, int event, 388 unsigned int flags) 389 { 390 struct rtmsg *rtm; 391 struct nlmsghdr *nlh; 392 unsigned char *b = skb->tail; 393 394 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags); 395 rtm = NLMSG_DATA(nlh); 396 rtm->rtm_family = AF_INET; 397 rtm->rtm_dst_len = r->r_dst_len; 398 rtm->rtm_src_len = r->r_src_len; 399 rtm->rtm_tos = r->r_tos; 400 #ifdef CONFIG_IP_ROUTE_FWMARK 401 if (r->r_fwmark) 402 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark); 403 #endif 404 rtm->rtm_table = r->r_table; 405 rtm->rtm_protocol = 0; 406 rtm->rtm_scope = 0; 407 rtm->rtm_type = r->r_action; 408 rtm->rtm_flags = r->r_flags; 409 410 if (r->r_dst_len) 411 RTA_PUT(skb, RTA_DST, 4, &r->r_dst); 412 if (r->r_src_len) 413 RTA_PUT(skb, RTA_SRC, 4, &r->r_src); 414 if (r->r_ifname[0]) 415 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname); 416 if (r->r_preference) 417 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference); 418 if (r->r_srcmap) 419 RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap); 420 #ifdef CONFIG_NET_CLS_ROUTE 421 if (r->r_tclassid) 422 RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid); 423 #endif 424 nlh->nlmsg_len = skb->tail - b; 425 return skb->len; 426 427 nlmsg_failure: 428 rtattr_failure: 429 skb_trim(skb, b - skb->data); 430 return -1; 431 } 432 433 /* callers should hold rtnl semaphore */ 434 435 static void rtmsg_rule(int event, struct fib_rule *r) 436 { 437 int size = NLMSG_SPACE(sizeof(struct rtmsg) + 128); 438 struct sk_buff *skb = alloc_skb(size, GFP_KERNEL); 439 440 if (!skb) 441 netlink_set_err(rtnl, 0, RTNLGRP_IPV4_RULE, ENOBUFS); 442 else if (inet_fill_rule(skb, r, 0, 0, event, 0) < 0) { 443 kfree_skb(skb); 444 netlink_set_err(rtnl, 0, RTNLGRP_IPV4_RULE, EINVAL); 445 } else { 446 netlink_broadcast(rtnl, skb, 0, RTNLGRP_IPV4_RULE, GFP_KERNEL); 447 } 448 } 449 450 int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb) 451 { 452 int idx = 0; 453 int s_idx = cb->args[0]; 454 struct fib_rule *r; 455 struct hlist_node *node; 456 457 rcu_read_lock(); 458 hlist_for_each_entry(r, node, &fib_rules, hlist) { 459 if (idx < s_idx) 460 goto next; 461 if (inet_fill_rule(skb, r, NETLINK_CB(cb->skb).pid, 462 cb->nlh->nlmsg_seq, 463 RTM_NEWRULE, NLM_F_MULTI) < 0) 464 break; 465 next: 466 idx++; 467 } 468 rcu_read_unlock(); 469 cb->args[0] = idx; 470 471 return skb->len; 472 } 473 474 void __init fib_rules_init(void) 475 { 476 INIT_HLIST_HEAD(&fib_rules); 477 hlist_add_head(&local_rule.hlist, &fib_rules); 478 hlist_add_after(&local_rule.hlist, &main_rule.hlist); 479 hlist_add_after(&main_rule.hlist, &default_rule.hlist); 480 register_netdevice_notifier(&fib_rules_notifier); 481 } 482