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 = pol_lookup_func(lookup, 115 net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 116 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 117 return &rt->dst; 118 ip6_rt_put_flags(rt, flags); 119 rt = pol_lookup_func(lookup, 120 net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 121 if (rt->dst.error != -EAGAIN) 122 return &rt->dst; 123 ip6_rt_put_flags(rt, flags); 124 } 125 126 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 127 dst_hold(&net->ipv6.ip6_null_entry->dst); 128 return &net->ipv6.ip6_null_entry->dst; 129 } 130 131 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 132 struct flowi6 *flp6, const struct net_device *dev) 133 { 134 struct fib6_rule *r = (struct fib6_rule *)rule; 135 136 /* If we need to find a source address for this traffic, 137 * we check the result if it meets requirement of the rule. 138 */ 139 if ((rule->flags & FIB_RULE_FIND_SADDR) && 140 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 141 struct in6_addr saddr; 142 143 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 144 rt6_flags2srcprefs(flags), &saddr)) 145 return -EAGAIN; 146 147 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 148 return -EAGAIN; 149 150 flp6->saddr = saddr; 151 } 152 153 return 0; 154 } 155 156 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 157 int flags, struct fib_lookup_arg *arg) 158 { 159 struct fib6_result *res = arg->result; 160 struct flowi6 *flp6 = &flp->u.ip6; 161 struct net *net = rule->fr_net; 162 struct fib6_table *table; 163 int err, *oif; 164 u32 tb_id; 165 166 switch (rule->action) { 167 case FR_ACT_TO_TBL: 168 break; 169 case FR_ACT_UNREACHABLE: 170 return -ENETUNREACH; 171 case FR_ACT_PROHIBIT: 172 return -EACCES; 173 case FR_ACT_BLACKHOLE: 174 default: 175 return -EINVAL; 176 } 177 178 tb_id = fib_rule_get_table(rule, arg); 179 table = fib6_get_table(net, tb_id); 180 if (!table) 181 return -EAGAIN; 182 183 oif = (int *)arg->lookup_data; 184 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 185 if (!err && res->f6i != net->ipv6.fib6_null_entry) 186 err = fib6_rule_saddr(net, rule, flags, flp6, 187 res->nh->fib_nh_dev); 188 else 189 err = -EAGAIN; 190 191 return err; 192 } 193 194 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 195 int flags, struct fib_lookup_arg *arg) 196 { 197 struct fib6_result *res = arg->result; 198 struct flowi6 *flp6 = &flp->u.ip6; 199 struct rt6_info *rt = NULL; 200 struct fib6_table *table; 201 struct net *net = rule->fr_net; 202 pol_lookup_t lookup = arg->lookup_ptr; 203 int err = 0; 204 u32 tb_id; 205 206 switch (rule->action) { 207 case FR_ACT_TO_TBL: 208 break; 209 case FR_ACT_UNREACHABLE: 210 err = -ENETUNREACH; 211 rt = net->ipv6.ip6_null_entry; 212 goto discard_pkt; 213 default: 214 case FR_ACT_BLACKHOLE: 215 err = -EINVAL; 216 rt = net->ipv6.ip6_blk_hole_entry; 217 goto discard_pkt; 218 case FR_ACT_PROHIBIT: 219 err = -EACCES; 220 rt = net->ipv6.ip6_prohibit_entry; 221 goto discard_pkt; 222 } 223 224 tb_id = fib_rule_get_table(rule, arg); 225 table = fib6_get_table(net, tb_id); 226 if (!table) { 227 err = -EAGAIN; 228 goto out; 229 } 230 231 rt = pol_lookup_func(lookup, 232 net, table, flp6, arg->lookup_data, flags); 233 if (rt != net->ipv6.ip6_null_entry) { 234 err = fib6_rule_saddr(net, rule, flags, flp6, 235 ip6_dst_idev(&rt->dst)->dev); 236 237 if (err == -EAGAIN) 238 goto again; 239 240 err = rt->dst.error; 241 if (err != -EAGAIN) 242 goto out; 243 } 244 again: 245 ip6_rt_put_flags(rt, flags); 246 err = -EAGAIN; 247 rt = NULL; 248 goto out; 249 250 discard_pkt: 251 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 252 dst_hold(&rt->dst); 253 out: 254 res->rt6 = 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 fib6_result *res = arg->result; 270 struct rt6_info *rt = res->rt6; 271 struct net_device *dev = NULL; 272 273 if (!rt) 274 return false; 275 276 if (rt->rt6i_idev) 277 dev = rt->rt6i_idev->dev; 278 279 /* do not accept result if the route does 280 * not meet the required prefix length 281 */ 282 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 283 goto suppress_route; 284 285 /* do not accept result if the route uses a device 286 * belonging to a forbidden interface group 287 */ 288 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 289 goto suppress_route; 290 291 return false; 292 293 suppress_route: 294 if (!(arg->flags & FIB_LOOKUP_NOREF)) 295 ip6_rt_put(rt); 296 return true; 297 } 298 299 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 300 { 301 struct fib6_rule *r = (struct fib6_rule *) rule; 302 struct flowi6 *fl6 = &fl->u.ip6; 303 304 if (r->dst.plen && 305 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 306 return 0; 307 308 /* 309 * If FIB_RULE_FIND_SADDR is set and we do not have a 310 * source address for the traffic, we defer check for 311 * source address. 312 */ 313 if (r->src.plen) { 314 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 315 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 316 r->src.plen)) 317 return 0; 318 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 319 return 0; 320 } 321 322 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 323 return 0; 324 325 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 326 return 0; 327 328 if (fib_rule_port_range_set(&rule->sport_range) && 329 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 330 return 0; 331 332 if (fib_rule_port_range_set(&rule->dport_range) && 333 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 334 return 0; 335 336 return 1; 337 } 338 339 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 340 FRA_GENERIC_POLICY, 341 }; 342 343 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 344 struct fib_rule_hdr *frh, 345 struct nlattr **tb, 346 struct netlink_ext_ack *extack) 347 { 348 int err = -EINVAL; 349 struct net *net = sock_net(skb->sk); 350 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 351 352 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 353 if (rule->table == RT6_TABLE_UNSPEC) { 354 NL_SET_ERR_MSG(extack, "Invalid table"); 355 goto errout; 356 } 357 358 if (fib6_new_table(net, rule->table) == NULL) { 359 err = -ENOBUFS; 360 goto errout; 361 } 362 } 363 364 if (frh->src_len) 365 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 366 367 if (frh->dst_len) 368 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 369 370 rule6->src.plen = frh->src_len; 371 rule6->dst.plen = frh->dst_len; 372 rule6->tclass = frh->tos; 373 374 if (fib_rule_requires_fldissect(rule)) 375 net->ipv6.fib6_rules_require_fldissect++; 376 377 net->ipv6.fib6_has_custom_rules = true; 378 err = 0; 379 errout: 380 return err; 381 } 382 383 static int fib6_rule_delete(struct fib_rule *rule) 384 { 385 struct net *net = rule->fr_net; 386 387 if (net->ipv6.fib6_rules_require_fldissect && 388 fib_rule_requires_fldissect(rule)) 389 net->ipv6.fib6_rules_require_fldissect--; 390 391 return 0; 392 } 393 394 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 395 struct nlattr **tb) 396 { 397 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 398 399 if (frh->src_len && (rule6->src.plen != frh->src_len)) 400 return 0; 401 402 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 403 return 0; 404 405 if (frh->tos && (rule6->tclass != frh->tos)) 406 return 0; 407 408 if (frh->src_len && 409 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 410 return 0; 411 412 if (frh->dst_len && 413 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 414 return 0; 415 416 return 1; 417 } 418 419 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 420 struct fib_rule_hdr *frh) 421 { 422 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 423 424 frh->dst_len = rule6->dst.plen; 425 frh->src_len = rule6->src.plen; 426 frh->tos = rule6->tclass; 427 428 if ((rule6->dst.plen && 429 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 430 (rule6->src.plen && 431 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 432 goto nla_put_failure; 433 return 0; 434 435 nla_put_failure: 436 return -ENOBUFS; 437 } 438 439 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 440 { 441 return nla_total_size(16) /* dst */ 442 + nla_total_size(16); /* src */ 443 } 444 445 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 446 .family = AF_INET6, 447 .rule_size = sizeof(struct fib6_rule), 448 .addr_size = sizeof(struct in6_addr), 449 .action = fib6_rule_action, 450 .match = fib6_rule_match, 451 .suppress = fib6_rule_suppress, 452 .configure = fib6_rule_configure, 453 .delete = fib6_rule_delete, 454 .compare = fib6_rule_compare, 455 .fill = fib6_rule_fill, 456 .nlmsg_payload = fib6_rule_nlmsg_payload, 457 .nlgroup = RTNLGRP_IPV6_RULE, 458 .policy = fib6_rule_policy, 459 .owner = THIS_MODULE, 460 .fro_net = &init_net, 461 }; 462 463 static int __net_init fib6_rules_net_init(struct net *net) 464 { 465 struct fib_rules_ops *ops; 466 int err = -ENOMEM; 467 468 ops = fib_rules_register(&fib6_rules_ops_template, net); 469 if (IS_ERR(ops)) 470 return PTR_ERR(ops); 471 472 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 473 if (err) 474 goto out_fib6_rules_ops; 475 476 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 477 if (err) 478 goto out_fib6_rules_ops; 479 480 net->ipv6.fib6_rules_ops = ops; 481 net->ipv6.fib6_rules_require_fldissect = 0; 482 out: 483 return err; 484 485 out_fib6_rules_ops: 486 fib_rules_unregister(ops); 487 goto out; 488 } 489 490 static void __net_exit fib6_rules_net_exit(struct net *net) 491 { 492 rtnl_lock(); 493 fib_rules_unregister(net->ipv6.fib6_rules_ops); 494 rtnl_unlock(); 495 } 496 497 static struct pernet_operations fib6_rules_net_ops = { 498 .init = fib6_rules_net_init, 499 .exit = fib6_rules_net_exit, 500 }; 501 502 int __init fib6_rules_init(void) 503 { 504 return register_pernet_subsys(&fib6_rules_net_ops); 505 } 506 507 508 void fib6_rules_cleanup(void) 509 { 510 unregister_pernet_subsys(&fib6_rules_net_ops); 511 } 512