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