1 /* 2 * net/ipv6/fib6_rules.c IPv6 Routing Policy Rules 3 * 4 * Copyright (C)2003-2006 Helsinki University of Technology 5 * Copyright (C)2003-2006 USAGI/WIDE Project 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation, version 2. 10 * 11 * Authors 12 * Thomas Graf <tgraf@suug.ch> 13 * Ville Nuorvala <vnuorval@tcs.hut.fi> 14 */ 15 16 #include <linux/netdevice.h> 17 #include <linux/notifier.h> 18 #include <linux/export.h> 19 20 #include <net/fib_rules.h> 21 #include <net/ipv6.h> 22 #include <net/addrconf.h> 23 #include <net/ip6_route.h> 24 #include <net/netlink.h> 25 26 struct fib6_rule { 27 struct fib_rule common; 28 struct rt6key src; 29 struct rt6key dst; 30 u8 tclass; 31 }; 32 33 static bool fib6_rule_matchall(const struct fib_rule *rule) 34 { 35 struct fib6_rule *r = container_of(rule, struct fib6_rule, common); 36 37 if (r->dst.plen || r->src.plen || r->tclass) 38 return false; 39 return fib_rule_matchall(rule); 40 } 41 42 bool fib6_rule_default(const struct fib_rule *rule) 43 { 44 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL || 45 rule->l3mdev) 46 return false; 47 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN) 48 return false; 49 return true; 50 } 51 EXPORT_SYMBOL_GPL(fib6_rule_default); 52 53 int fib6_rules_dump(struct net *net, struct notifier_block *nb) 54 { 55 return fib_rules_dump(net, nb, AF_INET6); 56 } 57 58 unsigned int fib6_rules_seq_read(struct net *net) 59 { 60 return fib_rules_seq_read(net, AF_INET6); 61 } 62 63 /* called with rcu lock held; no reference taken on fib6_info */ 64 struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 65 int flags) 66 { 67 struct fib6_info *f6i; 68 int err; 69 70 if (net->ipv6.fib6_has_custom_rules) { 71 struct fib_lookup_arg arg = { 72 .lookup_ptr = fib6_table_lookup, 73 .lookup_data = &oif, 74 .flags = FIB_LOOKUP_NOREF, 75 }; 76 77 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 78 79 err = fib_rules_lookup(net->ipv6.fib6_rules_ops, 80 flowi6_to_flowi(fl6), flags, &arg); 81 if (err) 82 return ERR_PTR(err); 83 84 f6i = arg.result ? : net->ipv6.fib6_null_entry; 85 } else { 86 f6i = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, 87 oif, fl6, flags); 88 if (!f6i || f6i == net->ipv6.fib6_null_entry) 89 f6i = fib6_table_lookup(net, net->ipv6.fib6_main_tbl, 90 oif, fl6, flags); 91 } 92 93 return f6i; 94 } 95 96 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 97 const struct sk_buff *skb, 98 int flags, pol_lookup_t lookup) 99 { 100 if (net->ipv6.fib6_has_custom_rules) { 101 struct fib_lookup_arg arg = { 102 .lookup_ptr = lookup, 103 .lookup_data = skb, 104 .flags = FIB_LOOKUP_NOREF, 105 }; 106 107 /* update flow if oif or iif point to device enslaved to l3mdev */ 108 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 109 110 fib_rules_lookup(net->ipv6.fib6_rules_ops, 111 flowi6_to_flowi(fl6), flags, &arg); 112 113 if (arg.result) 114 return arg.result; 115 } else { 116 struct rt6_info *rt; 117 118 rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 119 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 120 return &rt->dst; 121 ip6_rt_put(rt); 122 rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 123 if (rt->dst.error != -EAGAIN) 124 return &rt->dst; 125 ip6_rt_put(rt); 126 } 127 128 dst_hold(&net->ipv6.ip6_null_entry->dst); 129 return &net->ipv6.ip6_null_entry->dst; 130 } 131 132 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 133 struct flowi6 *flp6, const struct net_device *dev) 134 { 135 struct fib6_rule *r = (struct fib6_rule *)rule; 136 137 /* If we need to find a source address for this traffic, 138 * we check the result if it meets requirement of the rule. 139 */ 140 if ((rule->flags & FIB_RULE_FIND_SADDR) && 141 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 142 struct in6_addr saddr; 143 144 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 145 rt6_flags2srcprefs(flags), &saddr)) 146 return -EAGAIN; 147 148 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 149 return -EAGAIN; 150 151 flp6->saddr = saddr; 152 } 153 154 return 0; 155 } 156 157 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 158 int flags, struct fib_lookup_arg *arg) 159 { 160 struct flowi6 *flp6 = &flp->u.ip6; 161 struct net *net = rule->fr_net; 162 struct fib6_table *table; 163 struct fib6_info *f6i; 164 int err = -EAGAIN, *oif; 165 u32 tb_id; 166 167 switch (rule->action) { 168 case FR_ACT_TO_TBL: 169 break; 170 case FR_ACT_UNREACHABLE: 171 return -ENETUNREACH; 172 case FR_ACT_PROHIBIT: 173 return -EACCES; 174 case FR_ACT_BLACKHOLE: 175 default: 176 return -EINVAL; 177 } 178 179 tb_id = fib_rule_get_table(rule, arg); 180 table = fib6_get_table(net, tb_id); 181 if (!table) 182 return -EAGAIN; 183 184 oif = (int *)arg->lookup_data; 185 f6i = fib6_table_lookup(net, table, *oif, flp6, flags); 186 if (f6i != net->ipv6.fib6_null_entry) { 187 err = fib6_rule_saddr(net, rule, flags, flp6, 188 fib6_info_nh_dev(f6i)); 189 190 if (likely(!err)) 191 arg->result = f6i; 192 } 193 194 return err; 195 } 196 197 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 198 int flags, struct fib_lookup_arg *arg) 199 { 200 struct flowi6 *flp6 = &flp->u.ip6; 201 struct rt6_info *rt = NULL; 202 struct fib6_table *table; 203 struct net *net = rule->fr_net; 204 pol_lookup_t lookup = arg->lookup_ptr; 205 int err = 0; 206 u32 tb_id; 207 208 switch (rule->action) { 209 case FR_ACT_TO_TBL: 210 break; 211 case FR_ACT_UNREACHABLE: 212 err = -ENETUNREACH; 213 rt = net->ipv6.ip6_null_entry; 214 goto discard_pkt; 215 default: 216 case FR_ACT_BLACKHOLE: 217 err = -EINVAL; 218 rt = net->ipv6.ip6_blk_hole_entry; 219 goto discard_pkt; 220 case FR_ACT_PROHIBIT: 221 err = -EACCES; 222 rt = net->ipv6.ip6_prohibit_entry; 223 goto discard_pkt; 224 } 225 226 tb_id = fib_rule_get_table(rule, arg); 227 table = fib6_get_table(net, tb_id); 228 if (!table) { 229 err = -EAGAIN; 230 goto out; 231 } 232 233 rt = lookup(net, table, flp6, arg->lookup_data, flags); 234 if (rt != net->ipv6.ip6_null_entry) { 235 err = fib6_rule_saddr(net, rule, flags, flp6, 236 ip6_dst_idev(&rt->dst)->dev); 237 238 if (err == -EAGAIN) 239 goto again; 240 241 err = rt->dst.error; 242 if (err != -EAGAIN) 243 goto out; 244 } 245 again: 246 ip6_rt_put(rt); 247 err = -EAGAIN; 248 rt = NULL; 249 goto out; 250 251 discard_pkt: 252 dst_hold(&rt->dst); 253 out: 254 arg->result = rt; 255 return err; 256 } 257 258 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 259 int flags, struct fib_lookup_arg *arg) 260 { 261 if (arg->lookup_ptr == fib6_table_lookup) 262 return fib6_rule_action_alt(rule, flp, flags, arg); 263 264 return __fib6_rule_action(rule, flp, flags, arg); 265 } 266 267 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 268 { 269 struct rt6_info *rt = (struct rt6_info *) arg->result; 270 struct net_device *dev = NULL; 271 272 if (rt->rt6i_idev) 273 dev = rt->rt6i_idev->dev; 274 275 /* do not accept result if the route does 276 * not meet the required prefix length 277 */ 278 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 279 goto suppress_route; 280 281 /* do not accept result if the route uses a device 282 * belonging to a forbidden interface group 283 */ 284 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 285 goto suppress_route; 286 287 return false; 288 289 suppress_route: 290 ip6_rt_put(rt); 291 return true; 292 } 293 294 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 295 { 296 struct fib6_rule *r = (struct fib6_rule *) rule; 297 struct flowi6 *fl6 = &fl->u.ip6; 298 299 if (r->dst.plen && 300 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 301 return 0; 302 303 /* 304 * If FIB_RULE_FIND_SADDR is set and we do not have a 305 * source address for the traffic, we defer check for 306 * source address. 307 */ 308 if (r->src.plen) { 309 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 310 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 311 r->src.plen)) 312 return 0; 313 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 314 return 0; 315 } 316 317 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 318 return 0; 319 320 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 321 return 0; 322 323 if (fib_rule_port_range_set(&rule->sport_range) && 324 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 325 return 0; 326 327 if (fib_rule_port_range_set(&rule->dport_range) && 328 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 329 return 0; 330 331 return 1; 332 } 333 334 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 335 FRA_GENERIC_POLICY, 336 }; 337 338 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 339 struct fib_rule_hdr *frh, 340 struct nlattr **tb, 341 struct netlink_ext_ack *extack) 342 { 343 int err = -EINVAL; 344 struct net *net = sock_net(skb->sk); 345 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 346 347 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 348 if (rule->table == RT6_TABLE_UNSPEC) { 349 NL_SET_ERR_MSG(extack, "Invalid table"); 350 goto errout; 351 } 352 353 if (fib6_new_table(net, rule->table) == NULL) { 354 err = -ENOBUFS; 355 goto errout; 356 } 357 } 358 359 if (frh->src_len) 360 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 361 362 if (frh->dst_len) 363 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 364 365 rule6->src.plen = frh->src_len; 366 rule6->dst.plen = frh->dst_len; 367 rule6->tclass = frh->tos; 368 369 if (fib_rule_requires_fldissect(rule)) 370 net->ipv6.fib6_rules_require_fldissect++; 371 372 net->ipv6.fib6_has_custom_rules = true; 373 err = 0; 374 errout: 375 return err; 376 } 377 378 static int fib6_rule_delete(struct fib_rule *rule) 379 { 380 struct net *net = rule->fr_net; 381 382 if (net->ipv6.fib6_rules_require_fldissect && 383 fib_rule_requires_fldissect(rule)) 384 net->ipv6.fib6_rules_require_fldissect--; 385 386 return 0; 387 } 388 389 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 390 struct nlattr **tb) 391 { 392 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 393 394 if (frh->src_len && (rule6->src.plen != frh->src_len)) 395 return 0; 396 397 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 398 return 0; 399 400 if (frh->tos && (rule6->tclass != frh->tos)) 401 return 0; 402 403 if (frh->src_len && 404 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 405 return 0; 406 407 if (frh->dst_len && 408 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 409 return 0; 410 411 return 1; 412 } 413 414 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 415 struct fib_rule_hdr *frh) 416 { 417 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 418 419 frh->dst_len = rule6->dst.plen; 420 frh->src_len = rule6->src.plen; 421 frh->tos = rule6->tclass; 422 423 if ((rule6->dst.plen && 424 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 425 (rule6->src.plen && 426 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 427 goto nla_put_failure; 428 return 0; 429 430 nla_put_failure: 431 return -ENOBUFS; 432 } 433 434 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 435 { 436 return nla_total_size(16) /* dst */ 437 + nla_total_size(16); /* src */ 438 } 439 440 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 441 .family = AF_INET6, 442 .rule_size = sizeof(struct fib6_rule), 443 .addr_size = sizeof(struct in6_addr), 444 .action = fib6_rule_action, 445 .match = fib6_rule_match, 446 .suppress = fib6_rule_suppress, 447 .configure = fib6_rule_configure, 448 .delete = fib6_rule_delete, 449 .compare = fib6_rule_compare, 450 .fill = fib6_rule_fill, 451 .nlmsg_payload = fib6_rule_nlmsg_payload, 452 .nlgroup = RTNLGRP_IPV6_RULE, 453 .policy = fib6_rule_policy, 454 .owner = THIS_MODULE, 455 .fro_net = &init_net, 456 }; 457 458 static int __net_init fib6_rules_net_init(struct net *net) 459 { 460 struct fib_rules_ops *ops; 461 int err = -ENOMEM; 462 463 ops = fib_rules_register(&fib6_rules_ops_template, net); 464 if (IS_ERR(ops)) 465 return PTR_ERR(ops); 466 467 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 468 if (err) 469 goto out_fib6_rules_ops; 470 471 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 472 if (err) 473 goto out_fib6_rules_ops; 474 475 net->ipv6.fib6_rules_ops = ops; 476 net->ipv6.fib6_rules_require_fldissect = 0; 477 out: 478 return err; 479 480 out_fib6_rules_ops: 481 fib_rules_unregister(ops); 482 goto out; 483 } 484 485 static void __net_exit fib6_rules_net_exit(struct net *net) 486 { 487 rtnl_lock(); 488 fib_rules_unregister(net->ipv6.fib6_rules_ops); 489 rtnl_unlock(); 490 } 491 492 static struct pernet_operations fib6_rules_net_ops = { 493 .init = fib6_rules_net_init, 494 .exit = fib6_rules_net_exit, 495 }; 496 497 int __init fib6_rules_init(void) 498 { 499 return register_pernet_subsys(&fib6_rules_net_ops); 500 } 501 502 503 void fib6_rules_cleanup(void) 504 { 505 unregister_pernet_subsys(&fib6_rules_net_ops); 506 } 507