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 #include <linux/indirect_call_wrapper.h> 17 18 #include <net/fib_rules.h> 19 #include <net/inet_dscp.h> 20 #include <net/ipv6.h> 21 #include <net/addrconf.h> 22 #include <net/ip6_route.h> 23 #include <net/netlink.h> 24 25 struct fib6_rule { 26 struct fib_rule common; 27 struct rt6key src; 28 struct rt6key dst; 29 dscp_t dscp; 30 }; 31 32 static bool fib6_rule_matchall(const struct fib_rule *rule) 33 { 34 struct fib6_rule *r = container_of(rule, struct fib6_rule, common); 35 36 if (r->dst.plen || r->src.plen || r->dscp) 37 return false; 38 return fib_rule_matchall(rule); 39 } 40 41 bool fib6_rule_default(const struct fib_rule *rule) 42 { 43 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL || 44 rule->l3mdev) 45 return false; 46 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN) 47 return false; 48 return true; 49 } 50 EXPORT_SYMBOL_GPL(fib6_rule_default); 51 52 int fib6_rules_dump(struct net *net, struct notifier_block *nb, 53 struct netlink_ext_ack *extack) 54 { 55 return fib_rules_dump(net, nb, AF_INET6, extack); 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 = pol_lookup_func(lookup, 117 net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 118 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 119 return &rt->dst; 120 ip6_rt_put_flags(rt, flags); 121 rt = pol_lookup_func(lookup, 122 net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 123 if (rt->dst.error != -EAGAIN) 124 return &rt->dst; 125 ip6_rt_put_flags(rt, flags); 126 } 127 128 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 129 dst_hold(&net->ipv6.ip6_null_entry->dst); 130 return &net->ipv6.ip6_null_entry->dst; 131 } 132 133 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 134 struct flowi6 *flp6, const struct net_device *dev) 135 { 136 struct fib6_rule *r = (struct fib6_rule *)rule; 137 138 /* If we need to find a source address for this traffic, 139 * we check the result if it meets requirement of the rule. 140 */ 141 if ((rule->flags & FIB_RULE_FIND_SADDR) && 142 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 143 struct in6_addr saddr; 144 145 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 146 rt6_flags2srcprefs(flags), &saddr)) 147 return -EAGAIN; 148 149 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 150 return -EAGAIN; 151 152 flp6->saddr = saddr; 153 } 154 155 return 0; 156 } 157 158 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 159 int flags, struct fib_lookup_arg *arg) 160 { 161 struct fib6_result *res = arg->result; 162 struct flowi6 *flp6 = &flp->u.ip6; 163 struct net *net = rule->fr_net; 164 struct fib6_table *table; 165 int err, *oif; 166 u32 tb_id; 167 168 switch (rule->action) { 169 case FR_ACT_TO_TBL: 170 break; 171 case FR_ACT_UNREACHABLE: 172 return -ENETUNREACH; 173 case FR_ACT_PROHIBIT: 174 return -EACCES; 175 case FR_ACT_BLACKHOLE: 176 default: 177 return -EINVAL; 178 } 179 180 tb_id = fib_rule_get_table(rule, arg); 181 table = fib6_get_table(net, tb_id); 182 if (!table) 183 return -EAGAIN; 184 185 oif = (int *)arg->lookup_data; 186 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 187 if (!err && res->f6i != net->ipv6.fib6_null_entry) 188 err = fib6_rule_saddr(net, rule, flags, flp6, 189 res->nh->fib_nh_dev); 190 else 191 err = -EAGAIN; 192 193 return err; 194 } 195 196 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 197 int flags, struct fib_lookup_arg *arg) 198 { 199 struct fib6_result *res = arg->result; 200 struct flowi6 *flp6 = &flp->u.ip6; 201 struct rt6_info *rt = NULL; 202 struct fib6_table *table; 203 struct net *net = rule->fr_net; 204 pol_lookup_t lookup = arg->lookup_ptr; 205 int err = 0; 206 u32 tb_id; 207 208 switch (rule->action) { 209 case FR_ACT_TO_TBL: 210 break; 211 case FR_ACT_UNREACHABLE: 212 err = -ENETUNREACH; 213 rt = net->ipv6.ip6_null_entry; 214 goto discard_pkt; 215 default: 216 case FR_ACT_BLACKHOLE: 217 err = -EINVAL; 218 rt = net->ipv6.ip6_blk_hole_entry; 219 goto discard_pkt; 220 case FR_ACT_PROHIBIT: 221 err = -EACCES; 222 rt = net->ipv6.ip6_prohibit_entry; 223 goto discard_pkt; 224 } 225 226 tb_id = fib_rule_get_table(rule, arg); 227 table = fib6_get_table(net, tb_id); 228 if (!table) { 229 err = -EAGAIN; 230 goto out; 231 } 232 233 rt = pol_lookup_func(lookup, 234 net, table, flp6, arg->lookup_data, flags); 235 if (rt != net->ipv6.ip6_null_entry) { 236 err = fib6_rule_saddr(net, rule, flags, flp6, 237 ip6_dst_idev(&rt->dst)->dev); 238 239 if (err == -EAGAIN) 240 goto again; 241 242 err = rt->dst.error; 243 if (err != -EAGAIN) 244 goto out; 245 } 246 again: 247 ip6_rt_put_flags(rt, flags); 248 err = -EAGAIN; 249 rt = NULL; 250 goto out; 251 252 discard_pkt: 253 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 254 dst_hold(&rt->dst); 255 out: 256 res->rt6 = rt; 257 return err; 258 } 259 260 INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule, 261 struct flowi *flp, int flags, 262 struct fib_lookup_arg *arg) 263 { 264 if (arg->lookup_ptr == fib6_table_lookup) 265 return fib6_rule_action_alt(rule, flp, flags, arg); 266 267 return __fib6_rule_action(rule, flp, flags, arg); 268 } 269 270 INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule, 271 int flags, 272 struct fib_lookup_arg *arg) 273 { 274 struct fib6_result *res = arg->result; 275 struct rt6_info *rt = res->rt6; 276 struct net_device *dev = NULL; 277 278 if (!rt) 279 return false; 280 281 if (rt->rt6i_idev) 282 dev = rt->rt6i_idev->dev; 283 284 /* do not accept result if the route does 285 * not meet the required prefix length 286 */ 287 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 288 goto suppress_route; 289 290 /* do not accept result if the route uses a device 291 * belonging to a forbidden interface group 292 */ 293 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 294 goto suppress_route; 295 296 return false; 297 298 suppress_route: 299 ip6_rt_put_flags(rt, flags); 300 return true; 301 } 302 303 INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule, 304 struct flowi *fl, int flags) 305 { 306 struct fib6_rule *r = (struct fib6_rule *) rule; 307 struct flowi6 *fl6 = &fl->u.ip6; 308 309 if (r->dst.plen && 310 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 311 return 0; 312 313 /* 314 * If FIB_RULE_FIND_SADDR is set and we do not have a 315 * source address for the traffic, we defer check for 316 * source address. 317 */ 318 if (r->src.plen) { 319 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 320 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 321 r->src.plen)) 322 return 0; 323 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 324 return 0; 325 } 326 327 if (r->dscp && r->dscp != ip6_dscp(fl6->flowlabel)) 328 return 0; 329 330 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 331 return 0; 332 333 if (fib_rule_port_range_set(&rule->sport_range) && 334 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 335 return 0; 336 337 if (fib_rule_port_range_set(&rule->dport_range) && 338 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 339 return 0; 340 341 return 1; 342 } 343 344 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 345 struct fib_rule_hdr *frh, 346 struct nlattr **tb, 347 struct netlink_ext_ack *extack) 348 { 349 int err = -EINVAL; 350 struct net *net = sock_net(skb->sk); 351 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 352 353 if (!inet_validate_dscp(frh->tos)) { 354 NL_SET_ERR_MSG(extack, 355 "Invalid dsfield (tos): ECN bits must be 0"); 356 goto errout; 357 } 358 rule6->dscp = inet_dsfield_to_dscp(frh->tos); 359 360 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 361 if (rule->table == RT6_TABLE_UNSPEC) { 362 NL_SET_ERR_MSG(extack, "Invalid table"); 363 goto errout; 364 } 365 366 if (fib6_new_table(net, rule->table) == NULL) { 367 err = -ENOBUFS; 368 goto errout; 369 } 370 } 371 372 if (frh->src_len) 373 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 374 375 if (frh->dst_len) 376 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 377 378 rule6->src.plen = frh->src_len; 379 rule6->dst.plen = frh->dst_len; 380 381 if (fib_rule_requires_fldissect(rule)) 382 net->ipv6.fib6_rules_require_fldissect++; 383 384 net->ipv6.fib6_has_custom_rules = true; 385 err = 0; 386 errout: 387 return err; 388 } 389 390 static int fib6_rule_delete(struct fib_rule *rule) 391 { 392 struct net *net = rule->fr_net; 393 394 if (net->ipv6.fib6_rules_require_fldissect && 395 fib_rule_requires_fldissect(rule)) 396 net->ipv6.fib6_rules_require_fldissect--; 397 398 return 0; 399 } 400 401 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 402 struct nlattr **tb) 403 { 404 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 405 406 if (frh->src_len && (rule6->src.plen != frh->src_len)) 407 return 0; 408 409 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 410 return 0; 411 412 if (frh->tos && inet_dscp_to_dsfield(rule6->dscp) != frh->tos) 413 return 0; 414 415 if (frh->src_len && 416 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 417 return 0; 418 419 if (frh->dst_len && 420 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 421 return 0; 422 423 return 1; 424 } 425 426 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 427 struct fib_rule_hdr *frh) 428 { 429 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 430 431 frh->dst_len = rule6->dst.plen; 432 frh->src_len = rule6->src.plen; 433 frh->tos = inet_dscp_to_dsfield(rule6->dscp); 434 435 if ((rule6->dst.plen && 436 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 437 (rule6->src.plen && 438 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 439 goto nla_put_failure; 440 return 0; 441 442 nla_put_failure: 443 return -ENOBUFS; 444 } 445 446 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 447 { 448 return nla_total_size(16) /* dst */ 449 + nla_total_size(16); /* src */ 450 } 451 452 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 453 .family = AF_INET6, 454 .rule_size = sizeof(struct fib6_rule), 455 .addr_size = sizeof(struct in6_addr), 456 .action = fib6_rule_action, 457 .match = fib6_rule_match, 458 .suppress = fib6_rule_suppress, 459 .configure = fib6_rule_configure, 460 .delete = fib6_rule_delete, 461 .compare = fib6_rule_compare, 462 .fill = fib6_rule_fill, 463 .nlmsg_payload = fib6_rule_nlmsg_payload, 464 .nlgroup = RTNLGRP_IPV6_RULE, 465 .owner = THIS_MODULE, 466 .fro_net = &init_net, 467 }; 468 469 static int __net_init fib6_rules_net_init(struct net *net) 470 { 471 struct fib_rules_ops *ops; 472 int err; 473 474 ops = fib_rules_register(&fib6_rules_ops_template, net); 475 if (IS_ERR(ops)) 476 return PTR_ERR(ops); 477 478 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 479 if (err) 480 goto out_fib6_rules_ops; 481 482 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 483 if (err) 484 goto out_fib6_rules_ops; 485 486 net->ipv6.fib6_rules_ops = ops; 487 net->ipv6.fib6_rules_require_fldissect = 0; 488 out: 489 return err; 490 491 out_fib6_rules_ops: 492 fib_rules_unregister(ops); 493 goto out; 494 } 495 496 static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list) 497 { 498 struct net *net; 499 500 rtnl_lock(); 501 list_for_each_entry(net, net_list, exit_list) { 502 fib_rules_unregister(net->ipv6.fib6_rules_ops); 503 cond_resched(); 504 } 505 rtnl_unlock(); 506 } 507 508 static struct pernet_operations fib6_rules_net_ops = { 509 .init = fib6_rules_net_init, 510 .exit_batch = fib6_rules_net_exit_batch, 511 }; 512 513 int __init fib6_rules_init(void) 514 { 515 return register_pernet_subsys(&fib6_rules_net_ops); 516 } 517 518 519 void fib6_rules_cleanup(void) 520 { 521 unregister_pernet_subsys(&fib6_rules_net_ops); 522 } 523