1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * net/ipv6/fib6_rules.c IPv6 Routing Policy Rules 4 * 5 * Copyright (C)2003-2006 Helsinki University of Technology 6 * Copyright (C)2003-2006 USAGI/WIDE Project 7 * 8 * Authors 9 * Thomas Graf <tgraf@suug.ch> 10 * Ville Nuorvala <vnuorval@tcs.hut.fi> 11 */ 12 13 #include <linux/netdevice.h> 14 #include <linux/notifier.h> 15 #include <linux/export.h> 16 17 #include <net/fib_rules.h> 18 #include <net/ipv6.h> 19 #include <net/addrconf.h> 20 #include <net/ip6_route.h> 21 #include <net/netlink.h> 22 23 struct fib6_rule { 24 struct fib_rule common; 25 struct rt6key src; 26 struct rt6key dst; 27 u8 tclass; 28 }; 29 30 static bool fib6_rule_matchall(const struct fib_rule *rule) 31 { 32 struct fib6_rule *r = container_of(rule, struct fib6_rule, common); 33 34 if (r->dst.plen || r->src.plen || r->tclass) 35 return false; 36 return fib_rule_matchall(rule); 37 } 38 39 bool fib6_rule_default(const struct fib_rule *rule) 40 { 41 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL || 42 rule->l3mdev) 43 return false; 44 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN) 45 return false; 46 return true; 47 } 48 EXPORT_SYMBOL_GPL(fib6_rule_default); 49 50 int fib6_rules_dump(struct net *net, struct notifier_block *nb, 51 struct netlink_ext_ack *extack) 52 { 53 return fib_rules_dump(net, nb, AF_INET6, extack); 54 } 55 56 unsigned int fib6_rules_seq_read(struct net *net) 57 { 58 return fib_rules_seq_read(net, AF_INET6); 59 } 60 61 /* called with rcu lock held; no reference taken on fib6_info */ 62 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 63 struct fib6_result *res, int flags) 64 { 65 int err; 66 67 if (net->ipv6.fib6_has_custom_rules) { 68 struct fib_lookup_arg arg = { 69 .lookup_ptr = fib6_table_lookup, 70 .lookup_data = &oif, 71 .result = res, 72 .flags = FIB_LOOKUP_NOREF, 73 }; 74 75 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 76 77 err = fib_rules_lookup(net->ipv6.fib6_rules_ops, 78 flowi6_to_flowi(fl6), flags, &arg); 79 } else { 80 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif, 81 fl6, res, flags); 82 if (err || res->f6i == net->ipv6.fib6_null_entry) 83 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl, 84 oif, fl6, res, flags); 85 } 86 87 return err; 88 } 89 90 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 91 const struct sk_buff *skb, 92 int flags, pol_lookup_t lookup) 93 { 94 if (net->ipv6.fib6_has_custom_rules) { 95 struct fib6_result res = {}; 96 struct fib_lookup_arg arg = { 97 .lookup_ptr = lookup, 98 .lookup_data = skb, 99 .result = &res, 100 .flags = FIB_LOOKUP_NOREF, 101 }; 102 103 /* update flow if oif or iif point to device enslaved to l3mdev */ 104 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 105 106 fib_rules_lookup(net->ipv6.fib6_rules_ops, 107 flowi6_to_flowi(fl6), flags, &arg); 108 109 if (res.rt6) 110 return &res.rt6->dst; 111 } else { 112 struct rt6_info *rt; 113 114 rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 115 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 116 return &rt->dst; 117 ip6_rt_put_flags(rt, flags); 118 rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 119 if (rt->dst.error != -EAGAIN) 120 return &rt->dst; 121 ip6_rt_put_flags(rt, flags); 122 } 123 124 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 125 dst_hold(&net->ipv6.ip6_null_entry->dst); 126 return &net->ipv6.ip6_null_entry->dst; 127 } 128 129 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 130 struct flowi6 *flp6, const struct net_device *dev) 131 { 132 struct fib6_rule *r = (struct fib6_rule *)rule; 133 134 /* If we need to find a source address for this traffic, 135 * we check the result if it meets requirement of the rule. 136 */ 137 if ((rule->flags & FIB_RULE_FIND_SADDR) && 138 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 139 struct in6_addr saddr; 140 141 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 142 rt6_flags2srcprefs(flags), &saddr)) 143 return -EAGAIN; 144 145 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 146 return -EAGAIN; 147 148 flp6->saddr = saddr; 149 } 150 151 return 0; 152 } 153 154 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 155 int flags, struct fib_lookup_arg *arg) 156 { 157 struct fib6_result *res = arg->result; 158 struct flowi6 *flp6 = &flp->u.ip6; 159 struct net *net = rule->fr_net; 160 struct fib6_table *table; 161 int err, *oif; 162 u32 tb_id; 163 164 switch (rule->action) { 165 case FR_ACT_TO_TBL: 166 break; 167 case FR_ACT_UNREACHABLE: 168 return -ENETUNREACH; 169 case FR_ACT_PROHIBIT: 170 return -EACCES; 171 case FR_ACT_BLACKHOLE: 172 default: 173 return -EINVAL; 174 } 175 176 tb_id = fib_rule_get_table(rule, arg); 177 table = fib6_get_table(net, tb_id); 178 if (!table) 179 return -EAGAIN; 180 181 oif = (int *)arg->lookup_data; 182 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 183 if (!err && res->f6i != net->ipv6.fib6_null_entry) 184 err = fib6_rule_saddr(net, rule, flags, flp6, 185 res->nh->fib_nh_dev); 186 else 187 err = -EAGAIN; 188 189 return err; 190 } 191 192 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 193 int flags, struct fib_lookup_arg *arg) 194 { 195 struct fib6_result *res = arg->result; 196 struct flowi6 *flp6 = &flp->u.ip6; 197 struct rt6_info *rt = NULL; 198 struct fib6_table *table; 199 struct net *net = rule->fr_net; 200 pol_lookup_t lookup = arg->lookup_ptr; 201 int err = 0; 202 u32 tb_id; 203 204 switch (rule->action) { 205 case FR_ACT_TO_TBL: 206 break; 207 case FR_ACT_UNREACHABLE: 208 err = -ENETUNREACH; 209 rt = net->ipv6.ip6_null_entry; 210 goto discard_pkt; 211 default: 212 case FR_ACT_BLACKHOLE: 213 err = -EINVAL; 214 rt = net->ipv6.ip6_blk_hole_entry; 215 goto discard_pkt; 216 case FR_ACT_PROHIBIT: 217 err = -EACCES; 218 rt = net->ipv6.ip6_prohibit_entry; 219 goto discard_pkt; 220 } 221 222 tb_id = fib_rule_get_table(rule, arg); 223 table = fib6_get_table(net, tb_id); 224 if (!table) { 225 err = -EAGAIN; 226 goto out; 227 } 228 229 rt = lookup(net, table, flp6, arg->lookup_data, flags); 230 if (rt != net->ipv6.ip6_null_entry) { 231 err = fib6_rule_saddr(net, rule, flags, flp6, 232 ip6_dst_idev(&rt->dst)->dev); 233 234 if (err == -EAGAIN) 235 goto again; 236 237 err = rt->dst.error; 238 if (err != -EAGAIN) 239 goto out; 240 } 241 again: 242 ip6_rt_put_flags(rt, flags); 243 err = -EAGAIN; 244 rt = NULL; 245 goto out; 246 247 discard_pkt: 248 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 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 if (!(arg->flags & FIB_LOOKUP_NOREF)) 292 ip6_rt_put(rt); 293 return true; 294 } 295 296 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 297 { 298 struct fib6_rule *r = (struct fib6_rule *) rule; 299 struct flowi6 *fl6 = &fl->u.ip6; 300 301 if (r->dst.plen && 302 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 303 return 0; 304 305 /* 306 * If FIB_RULE_FIND_SADDR is set and we do not have a 307 * source address for the traffic, we defer check for 308 * source address. 309 */ 310 if (r->src.plen) { 311 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 312 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 313 r->src.plen)) 314 return 0; 315 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 316 return 0; 317 } 318 319 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 320 return 0; 321 322 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 323 return 0; 324 325 if (fib_rule_port_range_set(&rule->sport_range) && 326 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 327 return 0; 328 329 if (fib_rule_port_range_set(&rule->dport_range) && 330 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 331 return 0; 332 333 return 1; 334 } 335 336 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 337 FRA_GENERIC_POLICY, 338 }; 339 340 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 341 struct fib_rule_hdr *frh, 342 struct nlattr **tb, 343 struct netlink_ext_ack *extack) 344 { 345 int err = -EINVAL; 346 struct net *net = sock_net(skb->sk); 347 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 348 349 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 350 if (rule->table == RT6_TABLE_UNSPEC) { 351 NL_SET_ERR_MSG(extack, "Invalid table"); 352 goto errout; 353 } 354 355 if (fib6_new_table(net, rule->table) == NULL) { 356 err = -ENOBUFS; 357 goto errout; 358 } 359 } 360 361 if (frh->src_len) 362 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 363 364 if (frh->dst_len) 365 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 366 367 rule6->src.plen = frh->src_len; 368 rule6->dst.plen = frh->dst_len; 369 rule6->tclass = frh->tos; 370 371 if (fib_rule_requires_fldissect(rule)) 372 net->ipv6.fib6_rules_require_fldissect++; 373 374 net->ipv6.fib6_has_custom_rules = true; 375 err = 0; 376 errout: 377 return err; 378 } 379 380 static int fib6_rule_delete(struct fib_rule *rule) 381 { 382 struct net *net = rule->fr_net; 383 384 if (net->ipv6.fib6_rules_require_fldissect && 385 fib_rule_requires_fldissect(rule)) 386 net->ipv6.fib6_rules_require_fldissect--; 387 388 return 0; 389 } 390 391 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 392 struct nlattr **tb) 393 { 394 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 395 396 if (frh->src_len && (rule6->src.plen != frh->src_len)) 397 return 0; 398 399 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 400 return 0; 401 402 if (frh->tos && (rule6->tclass != frh->tos)) 403 return 0; 404 405 if (frh->src_len && 406 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 407 return 0; 408 409 if (frh->dst_len && 410 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 411 return 0; 412 413 return 1; 414 } 415 416 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 417 struct fib_rule_hdr *frh) 418 { 419 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 420 421 frh->dst_len = rule6->dst.plen; 422 frh->src_len = rule6->src.plen; 423 frh->tos = rule6->tclass; 424 425 if ((rule6->dst.plen && 426 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 427 (rule6->src.plen && 428 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 429 goto nla_put_failure; 430 return 0; 431 432 nla_put_failure: 433 return -ENOBUFS; 434 } 435 436 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 437 { 438 return nla_total_size(16) /* dst */ 439 + nla_total_size(16); /* src */ 440 } 441 442 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 443 .family = AF_INET6, 444 .rule_size = sizeof(struct fib6_rule), 445 .addr_size = sizeof(struct in6_addr), 446 .action = fib6_rule_action, 447 .match = fib6_rule_match, 448 .suppress = fib6_rule_suppress, 449 .configure = fib6_rule_configure, 450 .delete = fib6_rule_delete, 451 .compare = fib6_rule_compare, 452 .fill = fib6_rule_fill, 453 .nlmsg_payload = fib6_rule_nlmsg_payload, 454 .nlgroup = RTNLGRP_IPV6_RULE, 455 .policy = fib6_rule_policy, 456 .owner = THIS_MODULE, 457 .fro_net = &init_net, 458 }; 459 460 static int __net_init fib6_rules_net_init(struct net *net) 461 { 462 struct fib_rules_ops *ops; 463 int err = -ENOMEM; 464 465 ops = fib_rules_register(&fib6_rules_ops_template, net); 466 if (IS_ERR(ops)) 467 return PTR_ERR(ops); 468 469 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 470 if (err) 471 goto out_fib6_rules_ops; 472 473 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 474 if (err) 475 goto out_fib6_rules_ops; 476 477 net->ipv6.fib6_rules_ops = ops; 478 net->ipv6.fib6_rules_require_fldissect = 0; 479 out: 480 return err; 481 482 out_fib6_rules_ops: 483 fib_rules_unregister(ops); 484 goto out; 485 } 486 487 static void __net_exit fib6_rules_net_exit(struct net *net) 488 { 489 rtnl_lock(); 490 fib_rules_unregister(net->ipv6.fib6_rules_ops); 491 rtnl_unlock(); 492 } 493 494 static struct pernet_operations fib6_rules_net_ops = { 495 .init = fib6_rules_net_init, 496 .exit = fib6_rules_net_exit, 497 }; 498 499 int __init fib6_rules_init(void) 500 { 501 return register_pernet_subsys(&fib6_rules_net_ops); 502 } 503 504 505 void fib6_rules_cleanup(void) 506 { 507 unregister_pernet_subsys(&fib6_rules_net_ops); 508 } 509