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 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 65 struct fib6_result *res, int flags) 66 { 67 int err; 68 69 if (net->ipv6.fib6_has_custom_rules) { 70 struct fib_lookup_arg arg = { 71 .lookup_ptr = fib6_table_lookup, 72 .lookup_data = &oif, 73 .result = res, 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 } else { 82 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif, 83 fl6, res, flags); 84 if (err || res->f6i == net->ipv6.fib6_null_entry) 85 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl, 86 oif, fl6, res, flags); 87 } 88 89 return err; 90 } 91 92 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 93 const struct sk_buff *skb, 94 int flags, pol_lookup_t lookup) 95 { 96 if (net->ipv6.fib6_has_custom_rules) { 97 struct fib6_result res = {}; 98 struct fib_lookup_arg arg = { 99 .lookup_ptr = lookup, 100 .lookup_data = skb, 101 .result = &res, 102 .flags = FIB_LOOKUP_NOREF, 103 }; 104 105 /* update flow if oif or iif point to device enslaved to l3mdev */ 106 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 107 108 fib_rules_lookup(net->ipv6.fib6_rules_ops, 109 flowi6_to_flowi(fl6), flags, &arg); 110 111 if (res.rt6) 112 return &res.rt6->dst; 113 } else { 114 struct rt6_info *rt; 115 116 rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 117 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 118 return &rt->dst; 119 ip6_rt_put(rt); 120 rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 121 if (rt->dst.error != -EAGAIN) 122 return &rt->dst; 123 ip6_rt_put(rt); 124 } 125 126 dst_hold(&net->ipv6.ip6_null_entry->dst); 127 return &net->ipv6.ip6_null_entry->dst; 128 } 129 130 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 131 struct flowi6 *flp6, const struct net_device *dev) 132 { 133 struct fib6_rule *r = (struct fib6_rule *)rule; 134 135 /* If we need to find a source address for this traffic, 136 * we check the result if it meets requirement of the rule. 137 */ 138 if ((rule->flags & FIB_RULE_FIND_SADDR) && 139 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 140 struct in6_addr saddr; 141 142 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 143 rt6_flags2srcprefs(flags), &saddr)) 144 return -EAGAIN; 145 146 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 147 return -EAGAIN; 148 149 flp6->saddr = saddr; 150 } 151 152 return 0; 153 } 154 155 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 156 int flags, struct fib_lookup_arg *arg) 157 { 158 struct fib6_result *res = arg->result; 159 struct flowi6 *flp6 = &flp->u.ip6; 160 struct net *net = rule->fr_net; 161 struct fib6_table *table; 162 int err, *oif; 163 u32 tb_id; 164 165 switch (rule->action) { 166 case FR_ACT_TO_TBL: 167 break; 168 case FR_ACT_UNREACHABLE: 169 return -ENETUNREACH; 170 case FR_ACT_PROHIBIT: 171 return -EACCES; 172 case FR_ACT_BLACKHOLE: 173 default: 174 return -EINVAL; 175 } 176 177 tb_id = fib_rule_get_table(rule, arg); 178 table = fib6_get_table(net, tb_id); 179 if (!table) 180 return -EAGAIN; 181 182 oif = (int *)arg->lookup_data; 183 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 184 if (!err && res->f6i != net->ipv6.fib6_null_entry) 185 err = fib6_rule_saddr(net, rule, flags, flp6, 186 res->nh->fib_nh_dev); 187 else 188 err = -EAGAIN; 189 190 return err; 191 } 192 193 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 194 int flags, struct fib_lookup_arg *arg) 195 { 196 struct fib6_result *res = arg->result; 197 struct flowi6 *flp6 = &flp->u.ip6; 198 struct rt6_info *rt = NULL; 199 struct fib6_table *table; 200 struct net *net = rule->fr_net; 201 pol_lookup_t lookup = arg->lookup_ptr; 202 int err = 0; 203 u32 tb_id; 204 205 switch (rule->action) { 206 case FR_ACT_TO_TBL: 207 break; 208 case FR_ACT_UNREACHABLE: 209 err = -ENETUNREACH; 210 rt = net->ipv6.ip6_null_entry; 211 goto discard_pkt; 212 default: 213 case FR_ACT_BLACKHOLE: 214 err = -EINVAL; 215 rt = net->ipv6.ip6_blk_hole_entry; 216 goto discard_pkt; 217 case FR_ACT_PROHIBIT: 218 err = -EACCES; 219 rt = net->ipv6.ip6_prohibit_entry; 220 goto discard_pkt; 221 } 222 223 tb_id = fib_rule_get_table(rule, arg); 224 table = fib6_get_table(net, tb_id); 225 if (!table) { 226 err = -EAGAIN; 227 goto out; 228 } 229 230 rt = lookup(net, table, flp6, arg->lookup_data, flags); 231 if (rt != net->ipv6.ip6_null_entry) { 232 err = fib6_rule_saddr(net, rule, flags, flp6, 233 ip6_dst_idev(&rt->dst)->dev); 234 235 if (err == -EAGAIN) 236 goto again; 237 238 err = rt->dst.error; 239 if (err != -EAGAIN) 240 goto out; 241 } 242 again: 243 ip6_rt_put(rt); 244 err = -EAGAIN; 245 rt = NULL; 246 goto out; 247 248 discard_pkt: 249 dst_hold(&rt->dst); 250 out: 251 res->rt6 = rt; 252 return err; 253 } 254 255 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 256 int flags, struct fib_lookup_arg *arg) 257 { 258 if (arg->lookup_ptr == fib6_table_lookup) 259 return fib6_rule_action_alt(rule, flp, flags, arg); 260 261 return __fib6_rule_action(rule, flp, flags, arg); 262 } 263 264 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 265 { 266 struct fib6_result *res = arg->result; 267 struct rt6_info *rt = res->rt6; 268 struct net_device *dev = NULL; 269 270 if (!rt) 271 return false; 272 273 if (rt->rt6i_idev) 274 dev = rt->rt6i_idev->dev; 275 276 /* do not accept result if the route does 277 * not meet the required prefix length 278 */ 279 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 280 goto suppress_route; 281 282 /* do not accept result if the route uses a device 283 * belonging to a forbidden interface group 284 */ 285 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 286 goto suppress_route; 287 288 return false; 289 290 suppress_route: 291 ip6_rt_put(rt); 292 return true; 293 } 294 295 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 296 { 297 struct fib6_rule *r = (struct fib6_rule *) rule; 298 struct flowi6 *fl6 = &fl->u.ip6; 299 300 if (r->dst.plen && 301 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 302 return 0; 303 304 /* 305 * If FIB_RULE_FIND_SADDR is set and we do not have a 306 * source address for the traffic, we defer check for 307 * source address. 308 */ 309 if (r->src.plen) { 310 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 311 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 312 r->src.plen)) 313 return 0; 314 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 315 return 0; 316 } 317 318 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 319 return 0; 320 321 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 322 return 0; 323 324 if (fib_rule_port_range_set(&rule->sport_range) && 325 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 326 return 0; 327 328 if (fib_rule_port_range_set(&rule->dport_range) && 329 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 330 return 0; 331 332 return 1; 333 } 334 335 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 336 FRA_GENERIC_POLICY, 337 }; 338 339 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 340 struct fib_rule_hdr *frh, 341 struct nlattr **tb, 342 struct netlink_ext_ack *extack) 343 { 344 int err = -EINVAL; 345 struct net *net = sock_net(skb->sk); 346 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 347 348 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 349 if (rule->table == RT6_TABLE_UNSPEC) { 350 NL_SET_ERR_MSG(extack, "Invalid table"); 351 goto errout; 352 } 353 354 if (fib6_new_table(net, rule->table) == NULL) { 355 err = -ENOBUFS; 356 goto errout; 357 } 358 } 359 360 if (frh->src_len) 361 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 362 363 if (frh->dst_len) 364 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 365 366 rule6->src.plen = frh->src_len; 367 rule6->dst.plen = frh->dst_len; 368 rule6->tclass = frh->tos; 369 370 if (fib_rule_requires_fldissect(rule)) 371 net->ipv6.fib6_rules_require_fldissect++; 372 373 net->ipv6.fib6_has_custom_rules = true; 374 err = 0; 375 errout: 376 return err; 377 } 378 379 static int fib6_rule_delete(struct fib_rule *rule) 380 { 381 struct net *net = rule->fr_net; 382 383 if (net->ipv6.fib6_rules_require_fldissect && 384 fib_rule_requires_fldissect(rule)) 385 net->ipv6.fib6_rules_require_fldissect--; 386 387 return 0; 388 } 389 390 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 391 struct nlattr **tb) 392 { 393 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 394 395 if (frh->src_len && (rule6->src.plen != frh->src_len)) 396 return 0; 397 398 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 399 return 0; 400 401 if (frh->tos && (rule6->tclass != frh->tos)) 402 return 0; 403 404 if (frh->src_len && 405 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 406 return 0; 407 408 if (frh->dst_len && 409 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 410 return 0; 411 412 return 1; 413 } 414 415 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 416 struct fib_rule_hdr *frh) 417 { 418 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 419 420 frh->dst_len = rule6->dst.plen; 421 frh->src_len = rule6->src.plen; 422 frh->tos = rule6->tclass; 423 424 if ((rule6->dst.plen && 425 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 426 (rule6->src.plen && 427 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 428 goto nla_put_failure; 429 return 0; 430 431 nla_put_failure: 432 return -ENOBUFS; 433 } 434 435 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 436 { 437 return nla_total_size(16) /* dst */ 438 + nla_total_size(16); /* src */ 439 } 440 441 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 442 .family = AF_INET6, 443 .rule_size = sizeof(struct fib6_rule), 444 .addr_size = sizeof(struct in6_addr), 445 .action = fib6_rule_action, 446 .match = fib6_rule_match, 447 .suppress = fib6_rule_suppress, 448 .configure = fib6_rule_configure, 449 .delete = fib6_rule_delete, 450 .compare = fib6_rule_compare, 451 .fill = fib6_rule_fill, 452 .nlmsg_payload = fib6_rule_nlmsg_payload, 453 .nlgroup = RTNLGRP_IPV6_RULE, 454 .policy = fib6_rule_policy, 455 .owner = THIS_MODULE, 456 .fro_net = &init_net, 457 }; 458 459 static int __net_init fib6_rules_net_init(struct net *net) 460 { 461 struct fib_rules_ops *ops; 462 int err = -ENOMEM; 463 464 ops = fib_rules_register(&fib6_rules_ops_template, net); 465 if (IS_ERR(ops)) 466 return PTR_ERR(ops); 467 468 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 469 if (err) 470 goto out_fib6_rules_ops; 471 472 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 473 if (err) 474 goto out_fib6_rules_ops; 475 476 net->ipv6.fib6_rules_ops = ops; 477 net->ipv6.fib6_rules_require_fldissect = 0; 478 out: 479 return err; 480 481 out_fib6_rules_ops: 482 fib_rules_unregister(ops); 483 goto out; 484 } 485 486 static void __net_exit fib6_rules_net_exit(struct net *net) 487 { 488 rtnl_lock(); 489 fib_rules_unregister(net->ipv6.fib6_rules_ops); 490 rtnl_unlock(); 491 } 492 493 static struct pernet_operations fib6_rules_net_ops = { 494 .init = fib6_rules_net_init, 495 .exit = fib6_rules_net_exit, 496 }; 497 498 int __init fib6_rules_init(void) 499 { 500 return register_pernet_subsys(&fib6_rules_net_ops); 501 } 502 503 504 void fib6_rules_cleanup(void) 505 { 506 unregister_pernet_subsys(&fib6_rules_net_ops); 507 } 508