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 { 52 return fib_rules_dump(net, nb, AF_INET6); 53 } 54 55 unsigned int fib6_rules_seq_read(struct net *net) 56 { 57 return fib_rules_seq_read(net, AF_INET6); 58 } 59 60 /* called with rcu lock held; no reference taken on fib6_info */ 61 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 62 struct fib6_result *res, int flags) 63 { 64 int err; 65 66 if (net->ipv6.fib6_has_custom_rules) { 67 struct fib_lookup_arg arg = { 68 .lookup_ptr = fib6_table_lookup, 69 .lookup_data = &oif, 70 .result = res, 71 .flags = FIB_LOOKUP_NOREF, 72 }; 73 74 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 75 76 err = fib_rules_lookup(net->ipv6.fib6_rules_ops, 77 flowi6_to_flowi(fl6), flags, &arg); 78 } else { 79 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif, 80 fl6, res, flags); 81 if (err || res->f6i == net->ipv6.fib6_null_entry) 82 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl, 83 oif, fl6, res, flags); 84 } 85 86 return err; 87 } 88 89 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 90 const struct sk_buff *skb, 91 int flags, pol_lookup_t lookup) 92 { 93 if (net->ipv6.fib6_has_custom_rules) { 94 struct fib6_result res = {}; 95 struct fib_lookup_arg arg = { 96 .lookup_ptr = lookup, 97 .lookup_data = skb, 98 .result = &res, 99 .flags = FIB_LOOKUP_NOREF, 100 }; 101 102 /* update flow if oif or iif point to device enslaved to l3mdev */ 103 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 104 105 fib_rules_lookup(net->ipv6.fib6_rules_ops, 106 flowi6_to_flowi(fl6), flags, &arg); 107 108 if (res.rt6) 109 return &res.rt6->dst; 110 } else { 111 struct rt6_info *rt; 112 113 rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 114 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 115 return &rt->dst; 116 ip6_rt_put_flags(rt, flags); 117 rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 118 if (rt->dst.error != -EAGAIN) 119 return &rt->dst; 120 ip6_rt_put_flags(rt, flags); 121 } 122 123 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 124 dst_hold(&net->ipv6.ip6_null_entry->dst); 125 return &net->ipv6.ip6_null_entry->dst; 126 } 127 128 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 129 struct flowi6 *flp6, const struct net_device *dev) 130 { 131 struct fib6_rule *r = (struct fib6_rule *)rule; 132 133 /* If we need to find a source address for this traffic, 134 * we check the result if it meets requirement of the rule. 135 */ 136 if ((rule->flags & FIB_RULE_FIND_SADDR) && 137 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 138 struct in6_addr saddr; 139 140 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 141 rt6_flags2srcprefs(flags), &saddr)) 142 return -EAGAIN; 143 144 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 145 return -EAGAIN; 146 147 flp6->saddr = saddr; 148 } 149 150 return 0; 151 } 152 153 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 154 int flags, struct fib_lookup_arg *arg) 155 { 156 struct fib6_result *res = arg->result; 157 struct flowi6 *flp6 = &flp->u.ip6; 158 struct net *net = rule->fr_net; 159 struct fib6_table *table; 160 int err, *oif; 161 u32 tb_id; 162 163 switch (rule->action) { 164 case FR_ACT_TO_TBL: 165 break; 166 case FR_ACT_UNREACHABLE: 167 return -ENETUNREACH; 168 case FR_ACT_PROHIBIT: 169 return -EACCES; 170 case FR_ACT_BLACKHOLE: 171 default: 172 return -EINVAL; 173 } 174 175 tb_id = fib_rule_get_table(rule, arg); 176 table = fib6_get_table(net, tb_id); 177 if (!table) 178 return -EAGAIN; 179 180 oif = (int *)arg->lookup_data; 181 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 182 if (!err && res->f6i != net->ipv6.fib6_null_entry) 183 err = fib6_rule_saddr(net, rule, flags, flp6, 184 res->nh->fib_nh_dev); 185 else 186 err = -EAGAIN; 187 188 return err; 189 } 190 191 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 192 int flags, struct fib_lookup_arg *arg) 193 { 194 struct fib6_result *res = arg->result; 195 struct flowi6 *flp6 = &flp->u.ip6; 196 struct rt6_info *rt = NULL; 197 struct fib6_table *table; 198 struct net *net = rule->fr_net; 199 pol_lookup_t lookup = arg->lookup_ptr; 200 int err = 0; 201 u32 tb_id; 202 203 switch (rule->action) { 204 case FR_ACT_TO_TBL: 205 break; 206 case FR_ACT_UNREACHABLE: 207 err = -ENETUNREACH; 208 rt = net->ipv6.ip6_null_entry; 209 goto discard_pkt; 210 default: 211 case FR_ACT_BLACKHOLE: 212 err = -EINVAL; 213 rt = net->ipv6.ip6_blk_hole_entry; 214 goto discard_pkt; 215 case FR_ACT_PROHIBIT: 216 err = -EACCES; 217 rt = net->ipv6.ip6_prohibit_entry; 218 goto discard_pkt; 219 } 220 221 tb_id = fib_rule_get_table(rule, arg); 222 table = fib6_get_table(net, tb_id); 223 if (!table) { 224 err = -EAGAIN; 225 goto out; 226 } 227 228 rt = lookup(net, table, flp6, arg->lookup_data, flags); 229 if (rt != net->ipv6.ip6_null_entry) { 230 err = fib6_rule_saddr(net, rule, flags, flp6, 231 ip6_dst_idev(&rt->dst)->dev); 232 233 if (err == -EAGAIN) 234 goto again; 235 236 err = rt->dst.error; 237 if (err != -EAGAIN) 238 goto out; 239 } 240 again: 241 ip6_rt_put_flags(rt, flags); 242 err = -EAGAIN; 243 rt = NULL; 244 goto out; 245 246 discard_pkt: 247 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 248 dst_hold(&rt->dst); 249 out: 250 res->rt6 = rt; 251 return err; 252 } 253 254 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 255 int flags, struct fib_lookup_arg *arg) 256 { 257 if (arg->lookup_ptr == fib6_table_lookup) 258 return fib6_rule_action_alt(rule, flp, flags, arg); 259 260 return __fib6_rule_action(rule, flp, flags, arg); 261 } 262 263 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 264 { 265 struct fib6_result *res = arg->result; 266 struct rt6_info *rt = res->rt6; 267 struct net_device *dev = NULL; 268 269 if (!rt) 270 return false; 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