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 = kmalloc(sizeof(*new_r), GFP_KERNEL); 200 if (!new_r) 201 return -ENOMEM; 202 memset(new_r, 0, sizeof(*new_r)); 203 204 if (rta[RTA_SRC-1]) 205 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4); 206 if (rta[RTA_DST-1]) 207 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4); 208 if (rta[RTA_GATEWAY-1]) 209 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4); 210 new_r->r_src_len = rtm->rtm_src_len; 211 new_r->r_dst_len = rtm->rtm_dst_len; 212 new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len); 213 new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len); 214 new_r->r_tos = rtm->rtm_tos; 215 #ifdef CONFIG_IP_ROUTE_FWMARK 216 if (rta[RTA_PROTOINFO-1]) 217 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4); 218 #endif 219 new_r->r_action = rtm->rtm_type; 220 new_r->r_flags = rtm->rtm_flags; 221 if (rta[RTA_PRIORITY-1]) 222 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4); 223 new_r->r_table = table_id; 224 if (rta[RTA_IIF-1]) { 225 struct net_device *dev; 226 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ); 227 new_r->r_ifindex = -1; 228 dev = __dev_get_by_name(new_r->r_ifname); 229 if (dev) 230 new_r->r_ifindex = dev->ifindex; 231 } 232 #ifdef CONFIG_NET_CLS_ROUTE 233 if (rta[RTA_FLOW-1]) 234 memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4); 235 #endif 236 r = container_of(fib_rules.first, struct fib_rule, hlist); 237 238 if (!new_r->r_preference) { 239 if (r && r->hlist.next != NULL) { 240 r = container_of(r->hlist.next, struct fib_rule, hlist); 241 if (r->r_preference) 242 new_r->r_preference = r->r_preference - 1; 243 } 244 } 245 246 hlist_for_each_entry(r, node, &fib_rules, hlist) { 247 if (r->r_preference > new_r->r_preference) 248 break; 249 last = r; 250 } 251 atomic_inc(&new_r->r_clntref); 252 253 if (last) 254 hlist_add_after_rcu(&last->hlist, &new_r->hlist); 255 else 256 hlist_add_before_rcu(&new_r->hlist, &r->hlist); 257 258 rtmsg_rule(RTM_NEWRULE, new_r); 259 return 0; 260 } 261 262 #ifdef CONFIG_NET_CLS_ROUTE 263 u32 fib_rules_tclass(struct fib_result *res) 264 { 265 if (res->r) 266 return res->r->r_tclassid; 267 return 0; 268 } 269 #endif 270 271 /* callers should hold rtnl semaphore */ 272 273 static void fib_rules_detach(struct net_device *dev) 274 { 275 struct hlist_node *node; 276 struct fib_rule *r; 277 278 hlist_for_each_entry(r, node, &fib_rules, hlist) { 279 if (r->r_ifindex == dev->ifindex) 280 r->r_ifindex = -1; 281 282 } 283 } 284 285 /* callers should hold rtnl semaphore */ 286 287 static void fib_rules_attach(struct net_device *dev) 288 { 289 struct hlist_node *node; 290 struct fib_rule *r; 291 292 hlist_for_each_entry(r, node, &fib_rules, hlist) { 293 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) 294 r->r_ifindex = dev->ifindex; 295 } 296 } 297 298 int fib_lookup(const struct flowi *flp, struct fib_result *res) 299 { 300 int err; 301 struct fib_rule *r, *policy; 302 struct fib_table *tb; 303 struct hlist_node *node; 304 305 u32 daddr = flp->fl4_dst; 306 u32 saddr = flp->fl4_src; 307 308 FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ", 309 NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src)); 310 311 rcu_read_lock(); 312 313 hlist_for_each_entry_rcu(r, node, &fib_rules, hlist) { 314 if (((saddr^r->r_src) & r->r_srcmask) || 315 ((daddr^r->r_dst) & r->r_dstmask) || 316 (r->r_tos && r->r_tos != flp->fl4_tos) || 317 #ifdef CONFIG_IP_ROUTE_FWMARK 318 (r->r_fwmark && r->r_fwmark != flp->fl4_fwmark) || 319 #endif 320 (r->r_ifindex && r->r_ifindex != flp->iif)) 321 continue; 322 323 FRprintk("tb %d r %d ", r->r_table, r->r_action); 324 switch (r->r_action) { 325 case RTN_UNICAST: 326 policy = r; 327 break; 328 case RTN_UNREACHABLE: 329 rcu_read_unlock(); 330 return -ENETUNREACH; 331 default: 332 case RTN_BLACKHOLE: 333 rcu_read_unlock(); 334 return -EINVAL; 335 case RTN_PROHIBIT: 336 rcu_read_unlock(); 337 return -EACCES; 338 } 339 340 if ((tb = fib_get_table(r->r_table)) == NULL) 341 continue; 342 err = tb->tb_lookup(tb, flp, res); 343 if (err == 0) { 344 res->r = policy; 345 if (policy) 346 atomic_inc(&policy->r_clntref); 347 rcu_read_unlock(); 348 return 0; 349 } 350 if (err < 0 && err != -EAGAIN) { 351 rcu_read_unlock(); 352 return err; 353 } 354 } 355 FRprintk("FAILURE\n"); 356 rcu_read_unlock(); 357 return -ENETUNREACH; 358 } 359 360 void fib_select_default(const struct flowi *flp, struct fib_result *res) 361 { 362 if (res->r && res->r->r_action == RTN_UNICAST && 363 FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) { 364 struct fib_table *tb; 365 if ((tb = fib_get_table(res->r->r_table)) != NULL) 366 tb->tb_select_default(tb, flp, res); 367 } 368 } 369 370 static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr) 371 { 372 struct net_device *dev = ptr; 373 374 if (event == NETDEV_UNREGISTER) 375 fib_rules_detach(dev); 376 else if (event == NETDEV_REGISTER) 377 fib_rules_attach(dev); 378 return NOTIFY_DONE; 379 } 380 381 382 static struct notifier_block fib_rules_notifier = { 383 .notifier_call =fib_rules_event, 384 }; 385 386 static __inline__ int inet_fill_rule(struct sk_buff *skb, 387 struct fib_rule *r, 388 u32 pid, u32 seq, int event, 389 unsigned int flags) 390 { 391 struct rtmsg *rtm; 392 struct nlmsghdr *nlh; 393 unsigned char *b = skb->tail; 394 395 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags); 396 rtm = NLMSG_DATA(nlh); 397 rtm->rtm_family = AF_INET; 398 rtm->rtm_dst_len = r->r_dst_len; 399 rtm->rtm_src_len = r->r_src_len; 400 rtm->rtm_tos = r->r_tos; 401 #ifdef CONFIG_IP_ROUTE_FWMARK 402 if (r->r_fwmark) 403 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark); 404 #endif 405 rtm->rtm_table = r->r_table; 406 rtm->rtm_protocol = 0; 407 rtm->rtm_scope = 0; 408 rtm->rtm_type = r->r_action; 409 rtm->rtm_flags = r->r_flags; 410 411 if (r->r_dst_len) 412 RTA_PUT(skb, RTA_DST, 4, &r->r_dst); 413 if (r->r_src_len) 414 RTA_PUT(skb, RTA_SRC, 4, &r->r_src); 415 if (r->r_ifname[0]) 416 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname); 417 if (r->r_preference) 418 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference); 419 if (r->r_srcmap) 420 RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap); 421 #ifdef CONFIG_NET_CLS_ROUTE 422 if (r->r_tclassid) 423 RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid); 424 #endif 425 nlh->nlmsg_len = skb->tail - b; 426 return skb->len; 427 428 nlmsg_failure: 429 rtattr_failure: 430 skb_trim(skb, b - skb->data); 431 return -1; 432 } 433 434 /* callers should hold rtnl semaphore */ 435 436 static void rtmsg_rule(int event, struct fib_rule *r) 437 { 438 int size = NLMSG_SPACE(sizeof(struct rtmsg) + 128); 439 struct sk_buff *skb = alloc_skb(size, GFP_KERNEL); 440 441 if (!skb) 442 netlink_set_err(rtnl, 0, RTNLGRP_IPV4_RULE, ENOBUFS); 443 else if (inet_fill_rule(skb, r, 0, 0, event, 0) < 0) { 444 kfree_skb(skb); 445 netlink_set_err(rtnl, 0, RTNLGRP_IPV4_RULE, EINVAL); 446 } else { 447 netlink_broadcast(rtnl, skb, 0, RTNLGRP_IPV4_RULE, GFP_KERNEL); 448 } 449 } 450 451 int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb) 452 { 453 int idx = 0; 454 int s_idx = cb->args[0]; 455 struct fib_rule *r; 456 struct hlist_node *node; 457 458 rcu_read_lock(); 459 hlist_for_each_entry(r, node, &fib_rules, hlist) { 460 if (idx < s_idx) 461 goto next; 462 if (inet_fill_rule(skb, r, NETLINK_CB(cb->skb).pid, 463 cb->nlh->nlmsg_seq, 464 RTM_NEWRULE, NLM_F_MULTI) < 0) 465 break; 466 next: 467 idx++; 468 } 469 rcu_read_unlock(); 470 cb->args[0] = idx; 471 472 return skb->len; 473 } 474 475 void __init fib_rules_init(void) 476 { 477 INIT_HLIST_HEAD(&fib_rules); 478 hlist_add_head(&local_rule.hlist, &fib_rules); 479 hlist_add_after(&local_rule.hlist, &main_rule.hlist); 480 hlist_add_after(&main_rule.hlist, &default_rule.hlist); 481 register_netdevice_notifier(&fib_rules_notifier); 482 } 483