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 __be32 flowlabel; 30 __be32 flowlabel_mask; 31 dscp_t dscp; 32 u8 dscp_full:1; /* DSCP or TOS selector */ 33 }; 34 35 static bool fib6_rule_matchall(const struct fib_rule *rule) 36 { 37 struct fib6_rule *r = container_of(rule, struct fib6_rule, common); 38 39 if (r->dst.plen || r->src.plen || r->dscp || r->flowlabel_mask) 40 return false; 41 return fib_rule_matchall(rule); 42 } 43 44 bool fib6_rule_default(const struct fib_rule *rule) 45 { 46 if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL || 47 rule->l3mdev) 48 return false; 49 if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN) 50 return false; 51 return true; 52 } 53 EXPORT_SYMBOL_GPL(fib6_rule_default); 54 55 int fib6_rules_dump(struct net *net, struct notifier_block *nb, 56 struct netlink_ext_ack *extack) 57 { 58 return fib_rules_dump(net, nb, AF_INET6, extack); 59 } 60 61 unsigned int fib6_rules_seq_read(const struct net *net) 62 { 63 return fib_rules_seq_read(net, AF_INET6); 64 } 65 66 /* called with rcu lock held; no reference taken on fib6_info */ 67 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 68 struct fib6_result *res, int flags) 69 { 70 int err; 71 72 if (net->ipv6.fib6_has_custom_rules) { 73 struct fib_lookup_arg arg = { 74 .lookup_ptr = fib6_table_lookup, 75 .lookup_data = &oif, 76 .result = res, 77 .flags = FIB_LOOKUP_NOREF, 78 }; 79 80 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 81 82 err = fib_rules_lookup(net->ipv6.fib6_rules_ops, 83 flowi6_to_flowi(fl6), flags, &arg); 84 } else { 85 err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif, 86 fl6, res, flags); 87 if (err || res->f6i == net->ipv6.fib6_null_entry) 88 err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl, 89 oif, fl6, res, flags); 90 } 91 92 return err; 93 } 94 95 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 96 const struct sk_buff *skb, 97 int flags, pol_lookup_t lookup) 98 { 99 if (net->ipv6.fib6_has_custom_rules) { 100 struct fib6_result res = {}; 101 struct fib_lookup_arg arg = { 102 .lookup_ptr = lookup, 103 .lookup_data = skb, 104 .result = &res, 105 .flags = FIB_LOOKUP_NOREF, 106 }; 107 108 /* update flow if oif or iif point to device enslaved to l3mdev */ 109 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 110 111 fib_rules_lookup(net->ipv6.fib6_rules_ops, 112 flowi6_to_flowi(fl6), flags, &arg); 113 114 if (res.rt6) 115 return &res.rt6->dst; 116 } else { 117 struct rt6_info *rt; 118 119 rt = pol_lookup_func(lookup, 120 net, net->ipv6.fib6_local_tbl, fl6, skb, flags); 121 if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN) 122 return &rt->dst; 123 ip6_rt_put_flags(rt, flags); 124 rt = pol_lookup_func(lookup, 125 net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 126 if (rt->dst.error != -EAGAIN) 127 return &rt->dst; 128 ip6_rt_put_flags(rt, flags); 129 } 130 131 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 132 dst_hold(&net->ipv6.ip6_null_entry->dst); 133 return &net->ipv6.ip6_null_entry->dst; 134 } 135 136 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags, 137 struct flowi6 *flp6, const struct net_device *dev) 138 { 139 struct fib6_rule *r = (struct fib6_rule *)rule; 140 141 /* If we need to find a source address for this traffic, 142 * we check the result if it meets requirement of the rule. 143 */ 144 if ((rule->flags & FIB_RULE_FIND_SADDR) && 145 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 146 struct in6_addr saddr; 147 148 if (ipv6_dev_get_saddr(net, dev, &flp6->daddr, 149 rt6_flags2srcprefs(flags), &saddr)) 150 return -EAGAIN; 151 152 if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen)) 153 return -EAGAIN; 154 155 flp6->saddr = saddr; 156 } 157 158 return 0; 159 } 160 161 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp, 162 int flags, struct fib_lookup_arg *arg) 163 { 164 struct fib6_result *res = arg->result; 165 struct flowi6 *flp6 = &flp->u.ip6; 166 struct net *net = rule->fr_net; 167 struct fib6_table *table; 168 int err, *oif; 169 u32 tb_id; 170 171 switch (rule->action) { 172 case FR_ACT_TO_TBL: 173 break; 174 case FR_ACT_UNREACHABLE: 175 return -ENETUNREACH; 176 case FR_ACT_PROHIBIT: 177 return -EACCES; 178 case FR_ACT_BLACKHOLE: 179 default: 180 return -EINVAL; 181 } 182 183 tb_id = fib_rule_get_table(rule, arg); 184 table = fib6_get_table(net, tb_id); 185 if (!table) 186 return -EAGAIN; 187 188 oif = (int *)arg->lookup_data; 189 err = fib6_table_lookup(net, table, *oif, flp6, res, flags); 190 if (!err && res->f6i != net->ipv6.fib6_null_entry) 191 err = fib6_rule_saddr(net, rule, flags, flp6, 192 res->nh->fib_nh_dev); 193 else 194 err = -EAGAIN; 195 196 return err; 197 } 198 199 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 200 int flags, struct fib_lookup_arg *arg) 201 { 202 struct fib6_result *res = arg->result; 203 struct flowi6 *flp6 = &flp->u.ip6; 204 struct rt6_info *rt = NULL; 205 struct fib6_table *table; 206 struct net *net = rule->fr_net; 207 pol_lookup_t lookup = arg->lookup_ptr; 208 int err = 0; 209 u32 tb_id; 210 211 switch (rule->action) { 212 case FR_ACT_TO_TBL: 213 break; 214 case FR_ACT_UNREACHABLE: 215 err = -ENETUNREACH; 216 rt = net->ipv6.ip6_null_entry; 217 goto discard_pkt; 218 default: 219 case FR_ACT_BLACKHOLE: 220 err = -EINVAL; 221 rt = net->ipv6.ip6_blk_hole_entry; 222 goto discard_pkt; 223 case FR_ACT_PROHIBIT: 224 err = -EACCES; 225 rt = net->ipv6.ip6_prohibit_entry; 226 goto discard_pkt; 227 } 228 229 tb_id = fib_rule_get_table(rule, arg); 230 table = fib6_get_table(net, tb_id); 231 if (!table) { 232 err = -EAGAIN; 233 goto out; 234 } 235 236 rt = pol_lookup_func(lookup, 237 net, table, flp6, arg->lookup_data, flags); 238 if (rt != net->ipv6.ip6_null_entry) { 239 struct inet6_dev *idev = ip6_dst_idev(&rt->dst); 240 241 if (!idev) 242 goto again; 243 err = fib6_rule_saddr(net, rule, flags, flp6, 244 idev->dev); 245 246 if (err == -EAGAIN) 247 goto again; 248 249 err = rt->dst.error; 250 if (err != -EAGAIN) 251 goto out; 252 } 253 again: 254 ip6_rt_put_flags(rt, flags); 255 err = -EAGAIN; 256 rt = NULL; 257 goto out; 258 259 discard_pkt: 260 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 261 dst_hold(&rt->dst); 262 out: 263 res->rt6 = rt; 264 return err; 265 } 266 267 INDIRECT_CALLABLE_SCOPE int fib6_rule_action(struct fib_rule *rule, 268 struct flowi *flp, int flags, 269 struct fib_lookup_arg *arg) 270 { 271 if (arg->lookup_ptr == fib6_table_lookup) 272 return fib6_rule_action_alt(rule, flp, flags, arg); 273 274 return __fib6_rule_action(rule, flp, flags, arg); 275 } 276 277 INDIRECT_CALLABLE_SCOPE bool fib6_rule_suppress(struct fib_rule *rule, 278 int flags, 279 struct fib_lookup_arg *arg) 280 { 281 struct fib6_result *res = arg->result; 282 struct rt6_info *rt = res->rt6; 283 struct net_device *dev = NULL; 284 285 if (!rt) 286 return false; 287 288 if (rt->rt6i_idev) 289 dev = rt->rt6i_idev->dev; 290 291 /* do not accept result if the route does 292 * not meet the required prefix length 293 */ 294 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 295 goto suppress_route; 296 297 /* do not accept result if the route uses a device 298 * belonging to a forbidden interface group 299 */ 300 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 301 goto suppress_route; 302 303 return false; 304 305 suppress_route: 306 ip6_rt_put_flags(rt, flags); 307 return true; 308 } 309 310 INDIRECT_CALLABLE_SCOPE int fib6_rule_match(struct fib_rule *rule, 311 struct flowi *fl, int flags) 312 { 313 struct fib6_rule *r = (struct fib6_rule *) rule; 314 struct flowi6 *fl6 = &fl->u.ip6; 315 316 if (r->dst.plen && 317 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 318 return 0; 319 320 /* 321 * If FIB_RULE_FIND_SADDR is set and we do not have a 322 * source address for the traffic, we defer check for 323 * source address. 324 */ 325 if (r->src.plen) { 326 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 327 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 328 r->src.plen)) 329 return 0; 330 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 331 return 0; 332 } 333 334 if (r->dscp && r->dscp != ip6_dscp(fl6->flowlabel)) 335 return 0; 336 337 if ((r->flowlabel ^ flowi6_get_flowlabel(fl6)) & r->flowlabel_mask) 338 return 0; 339 340 if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto)) 341 return 0; 342 343 if (fib_rule_port_range_set(&rule->sport_range) && 344 !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport)) 345 return 0; 346 347 if (fib_rule_port_range_set(&rule->dport_range) && 348 !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport)) 349 return 0; 350 351 return 1; 352 } 353 354 static int fib6_nl2rule_dscp(const struct nlattr *nla, struct fib6_rule *rule6, 355 struct netlink_ext_ack *extack) 356 { 357 if (rule6->dscp) { 358 NL_SET_ERR_MSG(extack, "Cannot specify both TOS and DSCP"); 359 return -EINVAL; 360 } 361 362 rule6->dscp = inet_dsfield_to_dscp(nla_get_u8(nla) << 2); 363 rule6->dscp_full = true; 364 365 return 0; 366 } 367 368 static int fib6_nl2rule_flowlabel(struct nlattr **tb, struct fib6_rule *rule6, 369 struct netlink_ext_ack *extack) 370 { 371 __be32 flowlabel, flowlabel_mask; 372 373 if (NL_REQ_ATTR_CHECK(extack, NULL, tb, FRA_FLOWLABEL) || 374 NL_REQ_ATTR_CHECK(extack, NULL, tb, FRA_FLOWLABEL_MASK)) 375 return -EINVAL; 376 377 flowlabel = nla_get_be32(tb[FRA_FLOWLABEL]); 378 flowlabel_mask = nla_get_be32(tb[FRA_FLOWLABEL_MASK]); 379 380 if (flowlabel_mask & ~IPV6_FLOWLABEL_MASK) { 381 NL_SET_ERR_MSG_ATTR(extack, tb[FRA_FLOWLABEL_MASK], 382 "Invalid flow label mask"); 383 return -EINVAL; 384 } 385 386 if (flowlabel & ~flowlabel_mask) { 387 NL_SET_ERR_MSG(extack, "Flow label and mask do not match"); 388 return -EINVAL; 389 } 390 391 rule6->flowlabel = flowlabel; 392 rule6->flowlabel_mask = flowlabel_mask; 393 394 return 0; 395 } 396 397 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 398 struct fib_rule_hdr *frh, 399 struct nlattr **tb, 400 struct netlink_ext_ack *extack) 401 { 402 int err = -EINVAL; 403 struct net *net = sock_net(skb->sk); 404 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 405 406 if (!inet_validate_dscp(frh->tos)) { 407 NL_SET_ERR_MSG(extack, 408 "Invalid dsfield (tos): ECN bits must be 0"); 409 goto errout; 410 } 411 rule6->dscp = inet_dsfield_to_dscp(frh->tos); 412 413 if (tb[FRA_DSCP] && fib6_nl2rule_dscp(tb[FRA_DSCP], rule6, extack) < 0) 414 goto errout; 415 416 if ((tb[FRA_FLOWLABEL] || tb[FRA_FLOWLABEL_MASK]) && 417 fib6_nl2rule_flowlabel(tb, rule6, extack) < 0) 418 goto errout; 419 420 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 421 if (rule->table == RT6_TABLE_UNSPEC) { 422 NL_SET_ERR_MSG(extack, "Invalid table"); 423 goto errout; 424 } 425 426 if (fib6_new_table(net, rule->table) == NULL) { 427 err = -ENOBUFS; 428 goto errout; 429 } 430 } 431 432 if (frh->src_len) 433 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 434 435 if (frh->dst_len) 436 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 437 438 rule6->src.plen = frh->src_len; 439 rule6->dst.plen = frh->dst_len; 440 441 if (fib_rule_requires_fldissect(rule)) 442 net->ipv6.fib6_rules_require_fldissect++; 443 444 net->ipv6.fib6_has_custom_rules = true; 445 err = 0; 446 errout: 447 return err; 448 } 449 450 static int fib6_rule_delete(struct fib_rule *rule) 451 { 452 struct net *net = rule->fr_net; 453 454 if (net->ipv6.fib6_rules_require_fldissect && 455 fib_rule_requires_fldissect(rule)) 456 net->ipv6.fib6_rules_require_fldissect--; 457 458 return 0; 459 } 460 461 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 462 struct nlattr **tb) 463 { 464 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 465 466 if (frh->src_len && (rule6->src.plen != frh->src_len)) 467 return 0; 468 469 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 470 return 0; 471 472 if (frh->tos && 473 (rule6->dscp_full || 474 inet_dscp_to_dsfield(rule6->dscp) != frh->tos)) 475 return 0; 476 477 if (tb[FRA_DSCP]) { 478 dscp_t dscp; 479 480 dscp = inet_dsfield_to_dscp(nla_get_u8(tb[FRA_DSCP]) << 2); 481 if (!rule6->dscp_full || rule6->dscp != dscp) 482 return 0; 483 } 484 485 if (tb[FRA_FLOWLABEL] && 486 nla_get_be32(tb[FRA_FLOWLABEL]) != rule6->flowlabel) 487 return 0; 488 489 if (tb[FRA_FLOWLABEL_MASK] && 490 nla_get_be32(tb[FRA_FLOWLABEL_MASK]) != rule6->flowlabel_mask) 491 return 0; 492 493 if (frh->src_len && 494 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 495 return 0; 496 497 if (frh->dst_len && 498 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 499 return 0; 500 501 return 1; 502 } 503 504 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 505 struct fib_rule_hdr *frh) 506 { 507 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 508 509 frh->dst_len = rule6->dst.plen; 510 frh->src_len = rule6->src.plen; 511 512 if (rule6->dscp_full) { 513 frh->tos = 0; 514 if (nla_put_u8(skb, FRA_DSCP, 515 inet_dscp_to_dsfield(rule6->dscp) >> 2)) 516 goto nla_put_failure; 517 } else { 518 frh->tos = inet_dscp_to_dsfield(rule6->dscp); 519 } 520 521 if (rule6->flowlabel_mask && 522 (nla_put_be32(skb, FRA_FLOWLABEL, rule6->flowlabel) || 523 nla_put_be32(skb, FRA_FLOWLABEL_MASK, rule6->flowlabel_mask))) 524 goto nla_put_failure; 525 526 if ((rule6->dst.plen && 527 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 528 (rule6->src.plen && 529 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 530 goto nla_put_failure; 531 return 0; 532 533 nla_put_failure: 534 return -ENOBUFS; 535 } 536 537 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 538 { 539 return nla_total_size(16) /* dst */ 540 + nla_total_size(16) /* src */ 541 + nla_total_size(1) /* dscp */ 542 + nla_total_size(4) /* flowlabel */ 543 + nla_total_size(4); /* flowlabel mask */ 544 } 545 546 static void fib6_rule_flush_cache(struct fib_rules_ops *ops) 547 { 548 rt_genid_bump_ipv6(ops->fro_net); 549 } 550 551 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 552 .family = AF_INET6, 553 .rule_size = sizeof(struct fib6_rule), 554 .addr_size = sizeof(struct in6_addr), 555 .action = fib6_rule_action, 556 .match = fib6_rule_match, 557 .suppress = fib6_rule_suppress, 558 .configure = fib6_rule_configure, 559 .delete = fib6_rule_delete, 560 .compare = fib6_rule_compare, 561 .fill = fib6_rule_fill, 562 .nlmsg_payload = fib6_rule_nlmsg_payload, 563 .flush_cache = fib6_rule_flush_cache, 564 .nlgroup = RTNLGRP_IPV6_RULE, 565 .owner = THIS_MODULE, 566 .fro_net = &init_net, 567 }; 568 569 static int __net_init fib6_rules_net_init(struct net *net) 570 { 571 struct fib_rules_ops *ops; 572 int err; 573 574 ops = fib_rules_register(&fib6_rules_ops_template, net); 575 if (IS_ERR(ops)) 576 return PTR_ERR(ops); 577 578 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL); 579 if (err) 580 goto out_fib6_rules_ops; 581 582 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN); 583 if (err) 584 goto out_fib6_rules_ops; 585 586 net->ipv6.fib6_rules_ops = ops; 587 net->ipv6.fib6_rules_require_fldissect = 0; 588 out: 589 return err; 590 591 out_fib6_rules_ops: 592 fib_rules_unregister(ops); 593 goto out; 594 } 595 596 static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list) 597 { 598 struct net *net; 599 600 rtnl_lock(); 601 list_for_each_entry(net, net_list, exit_list) { 602 fib_rules_unregister(net->ipv6.fib6_rules_ops); 603 cond_resched(); 604 } 605 rtnl_unlock(); 606 } 607 608 static struct pernet_operations fib6_rules_net_ops = { 609 .init = fib6_rules_net_init, 610 .exit_batch = fib6_rules_net_exit_batch, 611 }; 612 613 int __init fib6_rules_init(void) 614 { 615 return register_pernet_subsys(&fib6_rules_net_ops); 616 } 617 618 619 void fib6_rules_cleanup(void) 620 { 621 unregister_pernet_subsys(&fib6_rules_net_ops); 622 } 623