1 // SPDX-License-Identifier: GPL-2.0 2 /* Generic nexthop implementation 3 * 4 * Copyright (c) 2017-19 Cumulus Networks 5 * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com> 6 */ 7 8 #include <linux/nexthop.h> 9 #include <linux/rtnetlink.h> 10 #include <linux/slab.h> 11 #include <net/arp.h> 12 #include <net/ipv6_stubs.h> 13 #include <net/lwtunnel.h> 14 #include <net/ndisc.h> 15 #include <net/nexthop.h> 16 #include <net/route.h> 17 #include <net/sock.h> 18 19 static void remove_nexthop(struct net *net, struct nexthop *nh, 20 struct nl_info *nlinfo); 21 22 #define NH_DEV_HASHBITS 8 23 #define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS) 24 25 static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = { 26 [NHA_ID] = { .type = NLA_U32 }, 27 [NHA_GROUP] = { .type = NLA_BINARY }, 28 [NHA_GROUP_TYPE] = { .type = NLA_U16 }, 29 [NHA_BLACKHOLE] = { .type = NLA_FLAG }, 30 [NHA_OIF] = { .type = NLA_U32 }, 31 [NHA_GATEWAY] = { .type = NLA_BINARY }, 32 [NHA_ENCAP_TYPE] = { .type = NLA_U16 }, 33 [NHA_ENCAP] = { .type = NLA_NESTED }, 34 [NHA_GROUPS] = { .type = NLA_FLAG }, 35 [NHA_MASTER] = { .type = NLA_U32 }, 36 [NHA_FDB] = { .type = NLA_FLAG }, 37 }; 38 39 static int call_nexthop_notifiers(struct net *net, 40 enum nexthop_event_type event_type, 41 struct nexthop *nh) 42 { 43 int err; 44 45 err = atomic_notifier_call_chain(&net->nexthop.notifier_chain, 46 event_type, nh); 47 return notifier_to_errno(err); 48 } 49 50 static unsigned int nh_dev_hashfn(unsigned int val) 51 { 52 unsigned int mask = NH_DEV_HASHSIZE - 1; 53 54 return (val ^ 55 (val >> NH_DEV_HASHBITS) ^ 56 (val >> (NH_DEV_HASHBITS * 2))) & mask; 57 } 58 59 static void nexthop_devhash_add(struct net *net, struct nh_info *nhi) 60 { 61 struct net_device *dev = nhi->fib_nhc.nhc_dev; 62 struct hlist_head *head; 63 unsigned int hash; 64 65 WARN_ON(!dev); 66 67 hash = nh_dev_hashfn(dev->ifindex); 68 head = &net->nexthop.devhash[hash]; 69 hlist_add_head(&nhi->dev_hash, head); 70 } 71 72 static void nexthop_free_mpath(struct nexthop *nh) 73 { 74 struct nh_group *nhg; 75 int i; 76 77 nhg = rcu_dereference_raw(nh->nh_grp); 78 for (i = 0; i < nhg->num_nh; ++i) { 79 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 80 81 WARN_ON(!list_empty(&nhge->nh_list)); 82 nexthop_put(nhge->nh); 83 } 84 85 WARN_ON(nhg->spare == nhg); 86 87 kfree(nhg->spare); 88 kfree(nhg); 89 } 90 91 static void nexthop_free_single(struct nexthop *nh) 92 { 93 struct nh_info *nhi; 94 95 nhi = rcu_dereference_raw(nh->nh_info); 96 switch (nhi->family) { 97 case AF_INET: 98 fib_nh_release(nh->net, &nhi->fib_nh); 99 break; 100 case AF_INET6: 101 ipv6_stub->fib6_nh_release(&nhi->fib6_nh); 102 break; 103 } 104 kfree(nhi); 105 } 106 107 void nexthop_free_rcu(struct rcu_head *head) 108 { 109 struct nexthop *nh = container_of(head, struct nexthop, rcu); 110 111 if (nh->is_group) 112 nexthop_free_mpath(nh); 113 else 114 nexthop_free_single(nh); 115 116 kfree(nh); 117 } 118 EXPORT_SYMBOL_GPL(nexthop_free_rcu); 119 120 static struct nexthop *nexthop_alloc(void) 121 { 122 struct nexthop *nh; 123 124 nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL); 125 if (nh) { 126 INIT_LIST_HEAD(&nh->fi_list); 127 INIT_LIST_HEAD(&nh->f6i_list); 128 INIT_LIST_HEAD(&nh->grp_list); 129 INIT_LIST_HEAD(&nh->fdb_list); 130 } 131 return nh; 132 } 133 134 static struct nh_group *nexthop_grp_alloc(u16 num_nh) 135 { 136 size_t sz = offsetof(struct nexthop, nh_grp) 137 + sizeof(struct nh_group) 138 + sizeof(struct nh_grp_entry) * num_nh; 139 struct nh_group *nhg; 140 141 nhg = kzalloc(sz, GFP_KERNEL); 142 if (nhg) 143 nhg->num_nh = num_nh; 144 145 return nhg; 146 } 147 148 static void nh_base_seq_inc(struct net *net) 149 { 150 while (++net->nexthop.seq == 0) 151 ; 152 } 153 154 /* no reference taken; rcu lock or rtnl must be held */ 155 struct nexthop *nexthop_find_by_id(struct net *net, u32 id) 156 { 157 struct rb_node **pp, *parent = NULL, *next; 158 159 pp = &net->nexthop.rb_root.rb_node; 160 while (1) { 161 struct nexthop *nh; 162 163 next = rcu_dereference_raw(*pp); 164 if (!next) 165 break; 166 parent = next; 167 168 nh = rb_entry(parent, struct nexthop, rb_node); 169 if (id < nh->id) 170 pp = &next->rb_left; 171 else if (id > nh->id) 172 pp = &next->rb_right; 173 else 174 return nh; 175 } 176 return NULL; 177 } 178 EXPORT_SYMBOL_GPL(nexthop_find_by_id); 179 180 /* used for auto id allocation; called with rtnl held */ 181 static u32 nh_find_unused_id(struct net *net) 182 { 183 u32 id_start = net->nexthop.last_id_allocated; 184 185 while (1) { 186 net->nexthop.last_id_allocated++; 187 if (net->nexthop.last_id_allocated == id_start) 188 break; 189 190 if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated)) 191 return net->nexthop.last_id_allocated; 192 } 193 return 0; 194 } 195 196 static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg) 197 { 198 struct nexthop_grp *p; 199 size_t len = nhg->num_nh * sizeof(*p); 200 struct nlattr *nla; 201 u16 group_type = 0; 202 int i; 203 204 if (nhg->mpath) 205 group_type = NEXTHOP_GRP_TYPE_MPATH; 206 207 if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type)) 208 goto nla_put_failure; 209 210 nla = nla_reserve(skb, NHA_GROUP, len); 211 if (!nla) 212 goto nla_put_failure; 213 214 p = nla_data(nla); 215 for (i = 0; i < nhg->num_nh; ++i) { 216 p->id = nhg->nh_entries[i].nh->id; 217 p->weight = nhg->nh_entries[i].weight - 1; 218 p += 1; 219 } 220 221 return 0; 222 223 nla_put_failure: 224 return -EMSGSIZE; 225 } 226 227 static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh, 228 int event, u32 portid, u32 seq, unsigned int nlflags) 229 { 230 struct fib6_nh *fib6_nh; 231 struct fib_nh *fib_nh; 232 struct nlmsghdr *nlh; 233 struct nh_info *nhi; 234 struct nhmsg *nhm; 235 236 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags); 237 if (!nlh) 238 return -EMSGSIZE; 239 240 nhm = nlmsg_data(nlh); 241 nhm->nh_family = AF_UNSPEC; 242 nhm->nh_flags = nh->nh_flags; 243 nhm->nh_protocol = nh->protocol; 244 nhm->nh_scope = 0; 245 nhm->resvd = 0; 246 247 if (nla_put_u32(skb, NHA_ID, nh->id)) 248 goto nla_put_failure; 249 250 if (nh->is_group) { 251 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 252 253 if (nhg->fdb_nh && nla_put_flag(skb, NHA_FDB)) 254 goto nla_put_failure; 255 if (nla_put_nh_group(skb, nhg)) 256 goto nla_put_failure; 257 goto out; 258 } 259 260 nhi = rtnl_dereference(nh->nh_info); 261 nhm->nh_family = nhi->family; 262 if (nhi->reject_nh) { 263 if (nla_put_flag(skb, NHA_BLACKHOLE)) 264 goto nla_put_failure; 265 goto out; 266 } else if (nhi->fdb_nh) { 267 if (nla_put_flag(skb, NHA_FDB)) 268 goto nla_put_failure; 269 } else { 270 const struct net_device *dev; 271 272 dev = nhi->fib_nhc.nhc_dev; 273 if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex)) 274 goto nla_put_failure; 275 } 276 277 nhm->nh_scope = nhi->fib_nhc.nhc_scope; 278 switch (nhi->family) { 279 case AF_INET: 280 fib_nh = &nhi->fib_nh; 281 if (fib_nh->fib_nh_gw_family && 282 nla_put_u32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4)) 283 goto nla_put_failure; 284 break; 285 286 case AF_INET6: 287 fib6_nh = &nhi->fib6_nh; 288 if (fib6_nh->fib_nh_gw_family && 289 nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6)) 290 goto nla_put_failure; 291 break; 292 } 293 294 if (nhi->fib_nhc.nhc_lwtstate && 295 lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate, 296 NHA_ENCAP, NHA_ENCAP_TYPE) < 0) 297 goto nla_put_failure; 298 299 out: 300 nlmsg_end(skb, nlh); 301 return 0; 302 303 nla_put_failure: 304 nlmsg_cancel(skb, nlh); 305 return -EMSGSIZE; 306 } 307 308 static size_t nh_nlmsg_size_grp(struct nexthop *nh) 309 { 310 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 311 size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh; 312 313 return nla_total_size(sz) + 314 nla_total_size(2); /* NHA_GROUP_TYPE */ 315 } 316 317 static size_t nh_nlmsg_size_single(struct nexthop *nh) 318 { 319 struct nh_info *nhi = rtnl_dereference(nh->nh_info); 320 size_t sz; 321 322 /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE 323 * are mutually exclusive 324 */ 325 sz = nla_total_size(4); /* NHA_OIF */ 326 327 switch (nhi->family) { 328 case AF_INET: 329 if (nhi->fib_nh.fib_nh_gw_family) 330 sz += nla_total_size(4); /* NHA_GATEWAY */ 331 break; 332 333 case AF_INET6: 334 /* NHA_GATEWAY */ 335 if (nhi->fib6_nh.fib_nh_gw_family) 336 sz += nla_total_size(sizeof(const struct in6_addr)); 337 break; 338 } 339 340 if (nhi->fib_nhc.nhc_lwtstate) { 341 sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate); 342 sz += nla_total_size(2); /* NHA_ENCAP_TYPE */ 343 } 344 345 return sz; 346 } 347 348 static size_t nh_nlmsg_size(struct nexthop *nh) 349 { 350 size_t sz = NLMSG_ALIGN(sizeof(struct nhmsg)); 351 352 sz += nla_total_size(4); /* NHA_ID */ 353 354 if (nh->is_group) 355 sz += nh_nlmsg_size_grp(nh); 356 else 357 sz += nh_nlmsg_size_single(nh); 358 359 return sz; 360 } 361 362 static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info) 363 { 364 unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0; 365 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 366 struct sk_buff *skb; 367 int err = -ENOBUFS; 368 369 skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any()); 370 if (!skb) 371 goto errout; 372 373 err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags); 374 if (err < 0) { 375 /* -EMSGSIZE implies BUG in nh_nlmsg_size() */ 376 WARN_ON(err == -EMSGSIZE); 377 kfree_skb(skb); 378 goto errout; 379 } 380 381 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP, 382 info->nlh, gfp_any()); 383 return; 384 errout: 385 if (err < 0) 386 rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err); 387 } 388 389 static bool valid_group_nh(struct nexthop *nh, unsigned int npaths, 390 bool *is_fdb, struct netlink_ext_ack *extack) 391 { 392 if (nh->is_group) { 393 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 394 395 /* nested multipath (group within a group) is not 396 * supported 397 */ 398 if (nhg->mpath) { 399 NL_SET_ERR_MSG(extack, 400 "Multipath group can not be a nexthop within a group"); 401 return false; 402 } 403 *is_fdb = nhg->fdb_nh; 404 } else { 405 struct nh_info *nhi = rtnl_dereference(nh->nh_info); 406 407 if (nhi->reject_nh && npaths > 1) { 408 NL_SET_ERR_MSG(extack, 409 "Blackhole nexthop can not be used in a group with more than 1 path"); 410 return false; 411 } 412 *is_fdb = nhi->fdb_nh; 413 } 414 415 return true; 416 } 417 418 static int nh_check_attr_fdb_group(struct nexthop *nh, u8 *nh_family, 419 struct netlink_ext_ack *extack) 420 { 421 struct nh_info *nhi; 422 423 nhi = rtnl_dereference(nh->nh_info); 424 425 if (!nhi->fdb_nh) { 426 NL_SET_ERR_MSG(extack, "FDB nexthop group can only have fdb nexthops"); 427 return -EINVAL; 428 } 429 430 if (*nh_family == AF_UNSPEC) { 431 *nh_family = nhi->family; 432 } else if (*nh_family != nhi->family) { 433 NL_SET_ERR_MSG(extack, "FDB nexthop group cannot have mixed family nexthops"); 434 return -EINVAL; 435 } 436 437 return 0; 438 } 439 440 static int nh_check_attr_group(struct net *net, struct nlattr *tb[], 441 struct netlink_ext_ack *extack) 442 { 443 unsigned int len = nla_len(tb[NHA_GROUP]); 444 u8 nh_family = AF_UNSPEC; 445 struct nexthop_grp *nhg; 446 unsigned int i, j; 447 u8 nhg_fdb = 0; 448 449 if (len & (sizeof(struct nexthop_grp) - 1)) { 450 NL_SET_ERR_MSG(extack, 451 "Invalid length for nexthop group attribute"); 452 return -EINVAL; 453 } 454 455 /* convert len to number of nexthop ids */ 456 len /= sizeof(*nhg); 457 458 nhg = nla_data(tb[NHA_GROUP]); 459 for (i = 0; i < len; ++i) { 460 if (nhg[i].resvd1 || nhg[i].resvd2) { 461 NL_SET_ERR_MSG(extack, "Reserved fields in nexthop_grp must be 0"); 462 return -EINVAL; 463 } 464 if (nhg[i].weight > 254) { 465 NL_SET_ERR_MSG(extack, "Invalid value for weight"); 466 return -EINVAL; 467 } 468 for (j = i + 1; j < len; ++j) { 469 if (nhg[i].id == nhg[j].id) { 470 NL_SET_ERR_MSG(extack, "Nexthop id can not be used twice in a group"); 471 return -EINVAL; 472 } 473 } 474 } 475 476 if (tb[NHA_FDB]) 477 nhg_fdb = 1; 478 nhg = nla_data(tb[NHA_GROUP]); 479 for (i = 0; i < len; ++i) { 480 struct nexthop *nh; 481 bool is_fdb_nh; 482 483 nh = nexthop_find_by_id(net, nhg[i].id); 484 if (!nh) { 485 NL_SET_ERR_MSG(extack, "Invalid nexthop id"); 486 return -EINVAL; 487 } 488 if (!valid_group_nh(nh, len, &is_fdb_nh, extack)) 489 return -EINVAL; 490 491 if (nhg_fdb && nh_check_attr_fdb_group(nh, &nh_family, extack)) 492 return -EINVAL; 493 494 if (!nhg_fdb && is_fdb_nh) { 495 NL_SET_ERR_MSG(extack, "Non FDB nexthop group cannot have fdb nexthops"); 496 return -EINVAL; 497 } 498 } 499 for (i = NHA_GROUP_TYPE + 1; i < __NHA_MAX; ++i) { 500 if (!tb[i]) 501 continue; 502 if (tb[NHA_FDB]) 503 continue; 504 NL_SET_ERR_MSG(extack, 505 "No other attributes can be set in nexthop groups"); 506 return -EINVAL; 507 } 508 509 return 0; 510 } 511 512 static bool ipv6_good_nh(const struct fib6_nh *nh) 513 { 514 int state = NUD_REACHABLE; 515 struct neighbour *n; 516 517 rcu_read_lock_bh(); 518 519 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6); 520 if (n) 521 state = n->nud_state; 522 523 rcu_read_unlock_bh(); 524 525 return !!(state & NUD_VALID); 526 } 527 528 static bool ipv4_good_nh(const struct fib_nh *nh) 529 { 530 int state = NUD_REACHABLE; 531 struct neighbour *n; 532 533 rcu_read_lock_bh(); 534 535 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 536 (__force u32)nh->fib_nh_gw4); 537 if (n) 538 state = n->nud_state; 539 540 rcu_read_unlock_bh(); 541 542 return !!(state & NUD_VALID); 543 } 544 545 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash) 546 { 547 struct nexthop *rc = NULL; 548 struct nh_group *nhg; 549 int i; 550 551 if (!nh->is_group) 552 return nh; 553 554 nhg = rcu_dereference(nh->nh_grp); 555 for (i = 0; i < nhg->num_nh; ++i) { 556 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 557 struct nh_info *nhi; 558 559 if (hash > atomic_read(&nhge->upper_bound)) 560 continue; 561 562 nhi = rcu_dereference(nhge->nh->nh_info); 563 if (nhi->fdb_nh) 564 return nhge->nh; 565 566 /* nexthops always check if it is good and does 567 * not rely on a sysctl for this behavior 568 */ 569 switch (nhi->family) { 570 case AF_INET: 571 if (ipv4_good_nh(&nhi->fib_nh)) 572 return nhge->nh; 573 break; 574 case AF_INET6: 575 if (ipv6_good_nh(&nhi->fib6_nh)) 576 return nhge->nh; 577 break; 578 } 579 580 if (!rc) 581 rc = nhge->nh; 582 } 583 584 return rc; 585 } 586 EXPORT_SYMBOL_GPL(nexthop_select_path); 587 588 int nexthop_for_each_fib6_nh(struct nexthop *nh, 589 int (*cb)(struct fib6_nh *nh, void *arg), 590 void *arg) 591 { 592 struct nh_info *nhi; 593 int err; 594 595 if (nh->is_group) { 596 struct nh_group *nhg; 597 int i; 598 599 nhg = rcu_dereference_rtnl(nh->nh_grp); 600 for (i = 0; i < nhg->num_nh; i++) { 601 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 602 603 nhi = rcu_dereference_rtnl(nhge->nh->nh_info); 604 err = cb(&nhi->fib6_nh, arg); 605 if (err) 606 return err; 607 } 608 } else { 609 nhi = rcu_dereference_rtnl(nh->nh_info); 610 err = cb(&nhi->fib6_nh, arg); 611 if (err) 612 return err; 613 } 614 615 return 0; 616 } 617 EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh); 618 619 static int check_src_addr(const struct in6_addr *saddr, 620 struct netlink_ext_ack *extack) 621 { 622 if (!ipv6_addr_any(saddr)) { 623 NL_SET_ERR_MSG(extack, "IPv6 routes using source address can not use nexthop objects"); 624 return -EINVAL; 625 } 626 return 0; 627 } 628 629 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg, 630 struct netlink_ext_ack *extack) 631 { 632 struct nh_info *nhi; 633 bool is_fdb_nh; 634 635 /* fib6_src is unique to a fib6_info and limits the ability to cache 636 * routes in fib6_nh within a nexthop that is potentially shared 637 * across multiple fib entries. If the config wants to use source 638 * routing it can not use nexthop objects. mlxsw also does not allow 639 * fib6_src on routes. 640 */ 641 if (cfg && check_src_addr(&cfg->fc_src, extack) < 0) 642 return -EINVAL; 643 644 if (nh->is_group) { 645 struct nh_group *nhg; 646 647 nhg = rtnl_dereference(nh->nh_grp); 648 if (nhg->has_v4) 649 goto no_v4_nh; 650 is_fdb_nh = nhg->fdb_nh; 651 } else { 652 nhi = rtnl_dereference(nh->nh_info); 653 if (nhi->family == AF_INET) 654 goto no_v4_nh; 655 is_fdb_nh = nhi->fdb_nh; 656 } 657 658 if (is_fdb_nh) { 659 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 660 return -EINVAL; 661 } 662 663 return 0; 664 no_v4_nh: 665 NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop"); 666 return -EINVAL; 667 } 668 EXPORT_SYMBOL_GPL(fib6_check_nexthop); 669 670 /* if existing nexthop has ipv6 routes linked to it, need 671 * to verify this new spec works with ipv6 672 */ 673 static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new, 674 struct netlink_ext_ack *extack) 675 { 676 struct fib6_info *f6i; 677 678 if (list_empty(&old->f6i_list)) 679 return 0; 680 681 list_for_each_entry(f6i, &old->f6i_list, nh_list) { 682 if (check_src_addr(&f6i->fib6_src.addr, extack) < 0) 683 return -EINVAL; 684 } 685 686 return fib6_check_nexthop(new, NULL, extack); 687 } 688 689 static int nexthop_check_scope(struct nh_info *nhi, u8 scope, 690 struct netlink_ext_ack *extack) 691 { 692 if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) { 693 NL_SET_ERR_MSG(extack, 694 "Route with host scope can not have a gateway"); 695 return -EINVAL; 696 } 697 698 if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) { 699 NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop"); 700 return -EINVAL; 701 } 702 703 return 0; 704 } 705 706 /* Invoked by fib add code to verify nexthop by id is ok with 707 * config for prefix; parts of fib_check_nh not done when nexthop 708 * object is used. 709 */ 710 int fib_check_nexthop(struct nexthop *nh, u8 scope, 711 struct netlink_ext_ack *extack) 712 { 713 struct nh_info *nhi; 714 int err = 0; 715 716 if (nh->is_group) { 717 struct nh_group *nhg; 718 719 nhg = rtnl_dereference(nh->nh_grp); 720 if (nhg->fdb_nh) { 721 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 722 err = -EINVAL; 723 goto out; 724 } 725 726 if (scope == RT_SCOPE_HOST) { 727 NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops"); 728 err = -EINVAL; 729 goto out; 730 } 731 732 /* all nexthops in a group have the same scope */ 733 nhi = rtnl_dereference(nhg->nh_entries[0].nh->nh_info); 734 err = nexthop_check_scope(nhi, scope, extack); 735 } else { 736 nhi = rtnl_dereference(nh->nh_info); 737 if (nhi->fdb_nh) { 738 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 739 err = -EINVAL; 740 goto out; 741 } 742 err = nexthop_check_scope(nhi, scope, extack); 743 } 744 745 out: 746 return err; 747 } 748 749 static int fib_check_nh_list(struct nexthop *old, struct nexthop *new, 750 struct netlink_ext_ack *extack) 751 { 752 struct fib_info *fi; 753 754 list_for_each_entry(fi, &old->fi_list, nh_list) { 755 int err; 756 757 err = fib_check_nexthop(new, fi->fib_scope, extack); 758 if (err) 759 return err; 760 } 761 return 0; 762 } 763 764 static void nh_group_rebalance(struct nh_group *nhg) 765 { 766 int total = 0; 767 int w = 0; 768 int i; 769 770 for (i = 0; i < nhg->num_nh; ++i) 771 total += nhg->nh_entries[i].weight; 772 773 for (i = 0; i < nhg->num_nh; ++i) { 774 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 775 int upper_bound; 776 777 w += nhge->weight; 778 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1; 779 atomic_set(&nhge->upper_bound, upper_bound); 780 } 781 } 782 783 static void remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge, 784 struct nl_info *nlinfo) 785 { 786 struct nh_grp_entry *nhges, *new_nhges; 787 struct nexthop *nhp = nhge->nh_parent; 788 struct nexthop *nh = nhge->nh; 789 struct nh_group *nhg, *newg; 790 int i, j; 791 792 WARN_ON(!nh); 793 794 nhg = rtnl_dereference(nhp->nh_grp); 795 newg = nhg->spare; 796 797 /* last entry, keep it visible and remove the parent */ 798 if (nhg->num_nh == 1) { 799 remove_nexthop(net, nhp, nlinfo); 800 return; 801 } 802 803 newg->has_v4 = nhg->has_v4; 804 newg->mpath = nhg->mpath; 805 newg->fdb_nh = nhg->fdb_nh; 806 newg->num_nh = nhg->num_nh; 807 808 /* copy old entries to new except the one getting removed */ 809 nhges = nhg->nh_entries; 810 new_nhges = newg->nh_entries; 811 for (i = 0, j = 0; i < nhg->num_nh; ++i) { 812 /* current nexthop getting removed */ 813 if (nhg->nh_entries[i].nh == nh) { 814 newg->num_nh--; 815 continue; 816 } 817 818 list_del(&nhges[i].nh_list); 819 new_nhges[j].nh_parent = nhges[i].nh_parent; 820 new_nhges[j].nh = nhges[i].nh; 821 new_nhges[j].weight = nhges[i].weight; 822 list_add(&new_nhges[j].nh_list, &new_nhges[j].nh->grp_list); 823 j++; 824 } 825 826 nh_group_rebalance(newg); 827 rcu_assign_pointer(nhp->nh_grp, newg); 828 829 list_del(&nhge->nh_list); 830 nexthop_put(nhge->nh); 831 832 if (nlinfo) 833 nexthop_notify(RTM_NEWNEXTHOP, nhp, nlinfo); 834 } 835 836 static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh, 837 struct nl_info *nlinfo) 838 { 839 struct nh_grp_entry *nhge, *tmp; 840 841 list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list) 842 remove_nh_grp_entry(net, nhge, nlinfo); 843 844 /* make sure all see the newly published array before releasing rtnl */ 845 synchronize_rcu(); 846 } 847 848 static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo) 849 { 850 struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp); 851 int i, num_nh = nhg->num_nh; 852 853 for (i = 0; i < num_nh; ++i) { 854 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 855 856 if (WARN_ON(!nhge->nh)) 857 continue; 858 859 list_del_init(&nhge->nh_list); 860 } 861 } 862 863 /* not called for nexthop replace */ 864 static void __remove_nexthop_fib(struct net *net, struct nexthop *nh) 865 { 866 struct fib6_info *f6i, *tmp; 867 bool do_flush = false; 868 struct fib_info *fi; 869 870 call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh); 871 872 list_for_each_entry(fi, &nh->fi_list, nh_list) { 873 fi->fib_flags |= RTNH_F_DEAD; 874 do_flush = true; 875 } 876 if (do_flush) 877 fib_flush(net); 878 879 /* ip6_del_rt removes the entry from this list hence the _safe */ 880 list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) { 881 /* __ip6_del_rt does a release, so do a hold here */ 882 fib6_info_hold(f6i); 883 ipv6_stub->ip6_del_rt(net, f6i, 884 !net->ipv4.sysctl_nexthop_compat_mode); 885 } 886 } 887 888 static void __remove_nexthop(struct net *net, struct nexthop *nh, 889 struct nl_info *nlinfo) 890 { 891 __remove_nexthop_fib(net, nh); 892 893 if (nh->is_group) { 894 remove_nexthop_group(nh, nlinfo); 895 } else { 896 struct nh_info *nhi; 897 898 nhi = rtnl_dereference(nh->nh_info); 899 if (nhi->fib_nhc.nhc_dev) 900 hlist_del(&nhi->dev_hash); 901 902 remove_nexthop_from_groups(net, nh, nlinfo); 903 } 904 } 905 906 static void remove_nexthop(struct net *net, struct nexthop *nh, 907 struct nl_info *nlinfo) 908 { 909 /* remove from the tree */ 910 rb_erase(&nh->rb_node, &net->nexthop.rb_root); 911 912 if (nlinfo) 913 nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo); 914 915 __remove_nexthop(net, nh, nlinfo); 916 nh_base_seq_inc(net); 917 918 nexthop_put(nh); 919 } 920 921 /* if any FIB entries reference this nexthop, any dst entries 922 * need to be regenerated 923 */ 924 static void nh_rt_cache_flush(struct net *net, struct nexthop *nh) 925 { 926 struct fib6_info *f6i; 927 928 if (!list_empty(&nh->fi_list)) 929 rt_cache_flush(net); 930 931 list_for_each_entry(f6i, &nh->f6i_list, nh_list) 932 ipv6_stub->fib6_update_sernum(net, f6i); 933 } 934 935 static int replace_nexthop_grp(struct net *net, struct nexthop *old, 936 struct nexthop *new, 937 struct netlink_ext_ack *extack) 938 { 939 struct nh_group *oldg, *newg; 940 int i; 941 942 if (!new->is_group) { 943 NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a nexthop."); 944 return -EINVAL; 945 } 946 947 oldg = rtnl_dereference(old->nh_grp); 948 newg = rtnl_dereference(new->nh_grp); 949 950 /* update parents - used by nexthop code for cleanup */ 951 for (i = 0; i < newg->num_nh; i++) 952 newg->nh_entries[i].nh_parent = old; 953 954 rcu_assign_pointer(old->nh_grp, newg); 955 956 for (i = 0; i < oldg->num_nh; i++) 957 oldg->nh_entries[i].nh_parent = new; 958 959 rcu_assign_pointer(new->nh_grp, oldg); 960 961 return 0; 962 } 963 964 static int replace_nexthop_single(struct net *net, struct nexthop *old, 965 struct nexthop *new, 966 struct netlink_ext_ack *extack) 967 { 968 struct nh_info *oldi, *newi; 969 970 if (new->is_group) { 971 NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a nexthop group."); 972 return -EINVAL; 973 } 974 975 oldi = rtnl_dereference(old->nh_info); 976 newi = rtnl_dereference(new->nh_info); 977 978 newi->nh_parent = old; 979 oldi->nh_parent = new; 980 981 old->protocol = new->protocol; 982 old->nh_flags = new->nh_flags; 983 984 rcu_assign_pointer(old->nh_info, newi); 985 rcu_assign_pointer(new->nh_info, oldi); 986 987 return 0; 988 } 989 990 static void __nexthop_replace_notify(struct net *net, struct nexthop *nh, 991 struct nl_info *info) 992 { 993 struct fib6_info *f6i; 994 995 if (!list_empty(&nh->fi_list)) { 996 struct fib_info *fi; 997 998 /* expectation is a few fib_info per nexthop and then 999 * a lot of routes per fib_info. So mark the fib_info 1000 * and then walk the fib tables once 1001 */ 1002 list_for_each_entry(fi, &nh->fi_list, nh_list) 1003 fi->nh_updated = true; 1004 1005 fib_info_notify_update(net, info); 1006 1007 list_for_each_entry(fi, &nh->fi_list, nh_list) 1008 fi->nh_updated = false; 1009 } 1010 1011 list_for_each_entry(f6i, &nh->f6i_list, nh_list) 1012 ipv6_stub->fib6_rt_update(net, f6i, info); 1013 } 1014 1015 /* send RTM_NEWROUTE with REPLACE flag set for all FIB entries 1016 * linked to this nexthop and for all groups that the nexthop 1017 * is a member of 1018 */ 1019 static void nexthop_replace_notify(struct net *net, struct nexthop *nh, 1020 struct nl_info *info) 1021 { 1022 struct nh_grp_entry *nhge; 1023 1024 __nexthop_replace_notify(net, nh, info); 1025 1026 list_for_each_entry(nhge, &nh->grp_list, nh_list) 1027 __nexthop_replace_notify(net, nhge->nh_parent, info); 1028 } 1029 1030 static int replace_nexthop(struct net *net, struct nexthop *old, 1031 struct nexthop *new, struct netlink_ext_ack *extack) 1032 { 1033 bool new_is_reject = false; 1034 struct nh_grp_entry *nhge; 1035 int err; 1036 1037 /* check that existing FIB entries are ok with the 1038 * new nexthop definition 1039 */ 1040 err = fib_check_nh_list(old, new, extack); 1041 if (err) 1042 return err; 1043 1044 err = fib6_check_nh_list(old, new, extack); 1045 if (err) 1046 return err; 1047 1048 if (!new->is_group) { 1049 struct nh_info *nhi = rtnl_dereference(new->nh_info); 1050 1051 new_is_reject = nhi->reject_nh; 1052 } 1053 1054 list_for_each_entry(nhge, &old->grp_list, nh_list) { 1055 /* if new nexthop is a blackhole, any groups using this 1056 * nexthop cannot have more than 1 path 1057 */ 1058 if (new_is_reject && 1059 nexthop_num_path(nhge->nh_parent) > 1) { 1060 NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a member of a group with more than one path"); 1061 return -EINVAL; 1062 } 1063 1064 err = fib_check_nh_list(nhge->nh_parent, new, extack); 1065 if (err) 1066 return err; 1067 1068 err = fib6_check_nh_list(nhge->nh_parent, new, extack); 1069 if (err) 1070 return err; 1071 } 1072 1073 if (old->is_group) 1074 err = replace_nexthop_grp(net, old, new, extack); 1075 else 1076 err = replace_nexthop_single(net, old, new, extack); 1077 1078 if (!err) { 1079 nh_rt_cache_flush(net, old); 1080 1081 __remove_nexthop(net, new, NULL); 1082 nexthop_put(new); 1083 } 1084 1085 return err; 1086 } 1087 1088 /* called with rtnl_lock held */ 1089 static int insert_nexthop(struct net *net, struct nexthop *new_nh, 1090 struct nh_config *cfg, struct netlink_ext_ack *extack) 1091 { 1092 struct rb_node **pp, *parent = NULL, *next; 1093 struct rb_root *root = &net->nexthop.rb_root; 1094 bool replace = !!(cfg->nlflags & NLM_F_REPLACE); 1095 bool create = !!(cfg->nlflags & NLM_F_CREATE); 1096 u32 new_id = new_nh->id; 1097 int replace_notify = 0; 1098 int rc = -EEXIST; 1099 1100 pp = &root->rb_node; 1101 while (1) { 1102 struct nexthop *nh; 1103 1104 next = rtnl_dereference(*pp); 1105 if (!next) 1106 break; 1107 1108 parent = next; 1109 1110 nh = rb_entry(parent, struct nexthop, rb_node); 1111 if (new_id < nh->id) { 1112 pp = &next->rb_left; 1113 } else if (new_id > nh->id) { 1114 pp = &next->rb_right; 1115 } else if (replace) { 1116 rc = replace_nexthop(net, nh, new_nh, extack); 1117 if (!rc) { 1118 new_nh = nh; /* send notification with old nh */ 1119 replace_notify = 1; 1120 } 1121 goto out; 1122 } else { 1123 /* id already exists and not a replace */ 1124 goto out; 1125 } 1126 } 1127 1128 if (replace && !create) { 1129 NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists"); 1130 rc = -ENOENT; 1131 goto out; 1132 } 1133 1134 rb_link_node_rcu(&new_nh->rb_node, parent, pp); 1135 rb_insert_color(&new_nh->rb_node, root); 1136 rc = 0; 1137 out: 1138 if (!rc) { 1139 nh_base_seq_inc(net); 1140 nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo); 1141 if (replace_notify && net->ipv4.sysctl_nexthop_compat_mode) 1142 nexthop_replace_notify(net, new_nh, &cfg->nlinfo); 1143 } 1144 1145 return rc; 1146 } 1147 1148 /* rtnl */ 1149 /* remove all nexthops tied to a device being deleted */ 1150 static void nexthop_flush_dev(struct net_device *dev) 1151 { 1152 unsigned int hash = nh_dev_hashfn(dev->ifindex); 1153 struct net *net = dev_net(dev); 1154 struct hlist_head *head = &net->nexthop.devhash[hash]; 1155 struct hlist_node *n; 1156 struct nh_info *nhi; 1157 1158 hlist_for_each_entry_safe(nhi, n, head, dev_hash) { 1159 if (nhi->fib_nhc.nhc_dev != dev) 1160 continue; 1161 1162 remove_nexthop(net, nhi->nh_parent, NULL); 1163 } 1164 } 1165 1166 /* rtnl; called when net namespace is deleted */ 1167 static void flush_all_nexthops(struct net *net) 1168 { 1169 struct rb_root *root = &net->nexthop.rb_root; 1170 struct rb_node *node; 1171 struct nexthop *nh; 1172 1173 while ((node = rb_first(root))) { 1174 nh = rb_entry(node, struct nexthop, rb_node); 1175 remove_nexthop(net, nh, NULL); 1176 cond_resched(); 1177 } 1178 } 1179 1180 static struct nexthop *nexthop_create_group(struct net *net, 1181 struct nh_config *cfg) 1182 { 1183 struct nlattr *grps_attr = cfg->nh_grp; 1184 struct nexthop_grp *entry = nla_data(grps_attr); 1185 u16 num_nh = nla_len(grps_attr) / sizeof(*entry); 1186 struct nh_group *nhg; 1187 struct nexthop *nh; 1188 int i; 1189 1190 nh = nexthop_alloc(); 1191 if (!nh) 1192 return ERR_PTR(-ENOMEM); 1193 1194 nh->is_group = 1; 1195 1196 nhg = nexthop_grp_alloc(num_nh); 1197 if (!nhg) { 1198 kfree(nh); 1199 return ERR_PTR(-ENOMEM); 1200 } 1201 1202 /* spare group used for removals */ 1203 nhg->spare = nexthop_grp_alloc(num_nh); 1204 if (!nhg->spare) { 1205 kfree(nhg); 1206 kfree(nh); 1207 return ERR_PTR(-ENOMEM); 1208 } 1209 nhg->spare->spare = nhg; 1210 1211 for (i = 0; i < nhg->num_nh; ++i) { 1212 struct nexthop *nhe; 1213 struct nh_info *nhi; 1214 1215 nhe = nexthop_find_by_id(net, entry[i].id); 1216 if (!nexthop_get(nhe)) 1217 goto out_no_nh; 1218 1219 nhi = rtnl_dereference(nhe->nh_info); 1220 if (nhi->family == AF_INET) 1221 nhg->has_v4 = true; 1222 1223 nhg->nh_entries[i].nh = nhe; 1224 nhg->nh_entries[i].weight = entry[i].weight + 1; 1225 list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list); 1226 nhg->nh_entries[i].nh_parent = nh; 1227 } 1228 1229 if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) { 1230 nhg->mpath = 1; 1231 nh_group_rebalance(nhg); 1232 } 1233 1234 if (cfg->nh_fdb) 1235 nhg->fdb_nh = 1; 1236 1237 rcu_assign_pointer(nh->nh_grp, nhg); 1238 1239 return nh; 1240 1241 out_no_nh: 1242 for (; i >= 0; --i) 1243 nexthop_put(nhg->nh_entries[i].nh); 1244 1245 kfree(nhg->spare); 1246 kfree(nhg); 1247 kfree(nh); 1248 1249 return ERR_PTR(-ENOENT); 1250 } 1251 1252 static int nh_create_ipv4(struct net *net, struct nexthop *nh, 1253 struct nh_info *nhi, struct nh_config *cfg, 1254 struct netlink_ext_ack *extack) 1255 { 1256 struct fib_nh *fib_nh = &nhi->fib_nh; 1257 struct fib_config fib_cfg = { 1258 .fc_oif = cfg->nh_ifindex, 1259 .fc_gw4 = cfg->gw.ipv4, 1260 .fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0, 1261 .fc_flags = cfg->nh_flags, 1262 .fc_encap = cfg->nh_encap, 1263 .fc_encap_type = cfg->nh_encap_type, 1264 }; 1265 u32 tb_id = (cfg->dev ? l3mdev_fib_table(cfg->dev) : RT_TABLE_MAIN); 1266 int err; 1267 1268 err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack); 1269 if (err) { 1270 fib_nh_release(net, fib_nh); 1271 goto out; 1272 } 1273 1274 if (nhi->fdb_nh) 1275 goto out; 1276 1277 /* sets nh_dev if successful */ 1278 err = fib_check_nh(net, fib_nh, tb_id, 0, extack); 1279 if (!err) { 1280 nh->nh_flags = fib_nh->fib_nh_flags; 1281 fib_info_update_nhc_saddr(net, &fib_nh->nh_common, 1282 fib_nh->fib_nh_scope); 1283 } else { 1284 fib_nh_release(net, fib_nh); 1285 } 1286 out: 1287 return err; 1288 } 1289 1290 static int nh_create_ipv6(struct net *net, struct nexthop *nh, 1291 struct nh_info *nhi, struct nh_config *cfg, 1292 struct netlink_ext_ack *extack) 1293 { 1294 struct fib6_nh *fib6_nh = &nhi->fib6_nh; 1295 struct fib6_config fib6_cfg = { 1296 .fc_table = l3mdev_fib_table(cfg->dev), 1297 .fc_ifindex = cfg->nh_ifindex, 1298 .fc_gateway = cfg->gw.ipv6, 1299 .fc_flags = cfg->nh_flags, 1300 .fc_encap = cfg->nh_encap, 1301 .fc_encap_type = cfg->nh_encap_type, 1302 .fc_is_fdb = cfg->nh_fdb, 1303 }; 1304 int err; 1305 1306 if (!ipv6_addr_any(&cfg->gw.ipv6)) 1307 fib6_cfg.fc_flags |= RTF_GATEWAY; 1308 1309 /* sets nh_dev if successful */ 1310 err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL, 1311 extack); 1312 if (err) 1313 ipv6_stub->fib6_nh_release(fib6_nh); 1314 else 1315 nh->nh_flags = fib6_nh->fib_nh_flags; 1316 1317 return err; 1318 } 1319 1320 static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg, 1321 struct netlink_ext_ack *extack) 1322 { 1323 struct nh_info *nhi; 1324 struct nexthop *nh; 1325 int err = 0; 1326 1327 nh = nexthop_alloc(); 1328 if (!nh) 1329 return ERR_PTR(-ENOMEM); 1330 1331 nhi = kzalloc(sizeof(*nhi), GFP_KERNEL); 1332 if (!nhi) { 1333 kfree(nh); 1334 return ERR_PTR(-ENOMEM); 1335 } 1336 1337 nh->nh_flags = cfg->nh_flags; 1338 nh->net = net; 1339 1340 nhi->nh_parent = nh; 1341 nhi->family = cfg->nh_family; 1342 nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK; 1343 1344 if (cfg->nh_fdb) 1345 nhi->fdb_nh = 1; 1346 1347 if (cfg->nh_blackhole) { 1348 nhi->reject_nh = 1; 1349 cfg->nh_ifindex = net->loopback_dev->ifindex; 1350 } 1351 1352 switch (cfg->nh_family) { 1353 case AF_INET: 1354 err = nh_create_ipv4(net, nh, nhi, cfg, extack); 1355 break; 1356 case AF_INET6: 1357 err = nh_create_ipv6(net, nh, nhi, cfg, extack); 1358 break; 1359 } 1360 1361 if (err) { 1362 kfree(nhi); 1363 kfree(nh); 1364 return ERR_PTR(err); 1365 } 1366 1367 /* add the entry to the device based hash */ 1368 if (!nhi->fdb_nh) 1369 nexthop_devhash_add(net, nhi); 1370 1371 rcu_assign_pointer(nh->nh_info, nhi); 1372 1373 return nh; 1374 } 1375 1376 /* called with rtnl lock held */ 1377 static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg, 1378 struct netlink_ext_ack *extack) 1379 { 1380 struct nexthop *nh; 1381 int err; 1382 1383 if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) { 1384 NL_SET_ERR_MSG(extack, "Replace requires nexthop id"); 1385 return ERR_PTR(-EINVAL); 1386 } 1387 1388 if (!cfg->nh_id) { 1389 cfg->nh_id = nh_find_unused_id(net); 1390 if (!cfg->nh_id) { 1391 NL_SET_ERR_MSG(extack, "No unused id"); 1392 return ERR_PTR(-EINVAL); 1393 } 1394 } 1395 1396 if (cfg->nh_grp) 1397 nh = nexthop_create_group(net, cfg); 1398 else 1399 nh = nexthop_create(net, cfg, extack); 1400 1401 if (IS_ERR(nh)) 1402 return nh; 1403 1404 refcount_set(&nh->refcnt, 1); 1405 nh->id = cfg->nh_id; 1406 nh->protocol = cfg->nh_protocol; 1407 nh->net = net; 1408 1409 err = insert_nexthop(net, nh, cfg, extack); 1410 if (err) { 1411 __remove_nexthop(net, nh, NULL); 1412 nexthop_put(nh); 1413 nh = ERR_PTR(err); 1414 } 1415 1416 return nh; 1417 } 1418 1419 static int rtm_to_nh_config(struct net *net, struct sk_buff *skb, 1420 struct nlmsghdr *nlh, struct nh_config *cfg, 1421 struct netlink_ext_ack *extack) 1422 { 1423 struct nhmsg *nhm = nlmsg_data(nlh); 1424 struct nlattr *tb[NHA_MAX + 1]; 1425 int err; 1426 1427 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1428 extack); 1429 if (err < 0) 1430 return err; 1431 1432 err = -EINVAL; 1433 if (nhm->resvd || nhm->nh_scope) { 1434 NL_SET_ERR_MSG(extack, "Invalid values in ancillary header"); 1435 goto out; 1436 } 1437 if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) { 1438 NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header"); 1439 goto out; 1440 } 1441 1442 switch (nhm->nh_family) { 1443 case AF_INET: 1444 case AF_INET6: 1445 break; 1446 case AF_UNSPEC: 1447 if (tb[NHA_GROUP]) 1448 break; 1449 fallthrough; 1450 default: 1451 NL_SET_ERR_MSG(extack, "Invalid address family"); 1452 goto out; 1453 } 1454 1455 if (tb[NHA_GROUPS] || tb[NHA_MASTER]) { 1456 NL_SET_ERR_MSG(extack, "Invalid attributes in request"); 1457 goto out; 1458 } 1459 1460 memset(cfg, 0, sizeof(*cfg)); 1461 cfg->nlflags = nlh->nlmsg_flags; 1462 cfg->nlinfo.portid = NETLINK_CB(skb).portid; 1463 cfg->nlinfo.nlh = nlh; 1464 cfg->nlinfo.nl_net = net; 1465 1466 cfg->nh_family = nhm->nh_family; 1467 cfg->nh_protocol = nhm->nh_protocol; 1468 cfg->nh_flags = nhm->nh_flags; 1469 1470 if (tb[NHA_ID]) 1471 cfg->nh_id = nla_get_u32(tb[NHA_ID]); 1472 1473 if (tb[NHA_FDB]) { 1474 if (tb[NHA_OIF] || tb[NHA_BLACKHOLE] || 1475 tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE]) { 1476 NL_SET_ERR_MSG(extack, "Fdb attribute can not be used with encap, oif or blackhole"); 1477 goto out; 1478 } 1479 if (nhm->nh_flags) { 1480 NL_SET_ERR_MSG(extack, "Unsupported nexthop flags in ancillary header"); 1481 goto out; 1482 } 1483 cfg->nh_fdb = nla_get_flag(tb[NHA_FDB]); 1484 } 1485 1486 if (tb[NHA_GROUP]) { 1487 if (nhm->nh_family != AF_UNSPEC) { 1488 NL_SET_ERR_MSG(extack, "Invalid family for group"); 1489 goto out; 1490 } 1491 cfg->nh_grp = tb[NHA_GROUP]; 1492 1493 cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH; 1494 if (tb[NHA_GROUP_TYPE]) 1495 cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]); 1496 1497 if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) { 1498 NL_SET_ERR_MSG(extack, "Invalid group type"); 1499 goto out; 1500 } 1501 err = nh_check_attr_group(net, tb, extack); 1502 1503 /* no other attributes should be set */ 1504 goto out; 1505 } 1506 1507 if (tb[NHA_BLACKHOLE]) { 1508 if (tb[NHA_GATEWAY] || tb[NHA_OIF] || 1509 tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE] || tb[NHA_FDB]) { 1510 NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway, oif, encap or fdb"); 1511 goto out; 1512 } 1513 1514 cfg->nh_blackhole = 1; 1515 err = 0; 1516 goto out; 1517 } 1518 1519 if (!cfg->nh_fdb && !tb[NHA_OIF]) { 1520 NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole and non-fdb nexthops"); 1521 goto out; 1522 } 1523 1524 if (!cfg->nh_fdb && tb[NHA_OIF]) { 1525 cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]); 1526 if (cfg->nh_ifindex) 1527 cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex); 1528 1529 if (!cfg->dev) { 1530 NL_SET_ERR_MSG(extack, "Invalid device index"); 1531 goto out; 1532 } else if (!(cfg->dev->flags & IFF_UP)) { 1533 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1534 err = -ENETDOWN; 1535 goto out; 1536 } else if (!netif_carrier_ok(cfg->dev)) { 1537 NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down"); 1538 err = -ENETDOWN; 1539 goto out; 1540 } 1541 } 1542 1543 err = -EINVAL; 1544 if (tb[NHA_GATEWAY]) { 1545 struct nlattr *gwa = tb[NHA_GATEWAY]; 1546 1547 switch (cfg->nh_family) { 1548 case AF_INET: 1549 if (nla_len(gwa) != sizeof(u32)) { 1550 NL_SET_ERR_MSG(extack, "Invalid gateway"); 1551 goto out; 1552 } 1553 cfg->gw.ipv4 = nla_get_be32(gwa); 1554 break; 1555 case AF_INET6: 1556 if (nla_len(gwa) != sizeof(struct in6_addr)) { 1557 NL_SET_ERR_MSG(extack, "Invalid gateway"); 1558 goto out; 1559 } 1560 cfg->gw.ipv6 = nla_get_in6_addr(gwa); 1561 break; 1562 default: 1563 NL_SET_ERR_MSG(extack, 1564 "Unknown address family for gateway"); 1565 goto out; 1566 } 1567 } else { 1568 /* device only nexthop (no gateway) */ 1569 if (cfg->nh_flags & RTNH_F_ONLINK) { 1570 NL_SET_ERR_MSG(extack, 1571 "ONLINK flag can not be set for nexthop without a gateway"); 1572 goto out; 1573 } 1574 } 1575 1576 if (tb[NHA_ENCAP]) { 1577 cfg->nh_encap = tb[NHA_ENCAP]; 1578 1579 if (!tb[NHA_ENCAP_TYPE]) { 1580 NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing"); 1581 goto out; 1582 } 1583 1584 cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]); 1585 err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack); 1586 if (err < 0) 1587 goto out; 1588 1589 } else if (tb[NHA_ENCAP_TYPE]) { 1590 NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing"); 1591 goto out; 1592 } 1593 1594 1595 err = 0; 1596 out: 1597 return err; 1598 } 1599 1600 /* rtnl */ 1601 static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh, 1602 struct netlink_ext_ack *extack) 1603 { 1604 struct net *net = sock_net(skb->sk); 1605 struct nh_config cfg; 1606 struct nexthop *nh; 1607 int err; 1608 1609 err = rtm_to_nh_config(net, skb, nlh, &cfg, extack); 1610 if (!err) { 1611 nh = nexthop_add(net, &cfg, extack); 1612 if (IS_ERR(nh)) 1613 err = PTR_ERR(nh); 1614 } 1615 1616 return err; 1617 } 1618 1619 static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id, 1620 struct netlink_ext_ack *extack) 1621 { 1622 struct nhmsg *nhm = nlmsg_data(nlh); 1623 struct nlattr *tb[NHA_MAX + 1]; 1624 int err, i; 1625 1626 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1627 extack); 1628 if (err < 0) 1629 return err; 1630 1631 err = -EINVAL; 1632 for (i = 0; i < __NHA_MAX; ++i) { 1633 if (!tb[i]) 1634 continue; 1635 1636 switch (i) { 1637 case NHA_ID: 1638 break; 1639 default: 1640 NL_SET_ERR_MSG_ATTR(extack, tb[i], 1641 "Unexpected attribute in request"); 1642 goto out; 1643 } 1644 } 1645 if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) { 1646 NL_SET_ERR_MSG(extack, "Invalid values in header"); 1647 goto out; 1648 } 1649 1650 if (!tb[NHA_ID]) { 1651 NL_SET_ERR_MSG(extack, "Nexthop id is missing"); 1652 goto out; 1653 } 1654 1655 *id = nla_get_u32(tb[NHA_ID]); 1656 if (!(*id)) 1657 NL_SET_ERR_MSG(extack, "Invalid nexthop id"); 1658 else 1659 err = 0; 1660 out: 1661 return err; 1662 } 1663 1664 /* rtnl */ 1665 static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh, 1666 struct netlink_ext_ack *extack) 1667 { 1668 struct net *net = sock_net(skb->sk); 1669 struct nl_info nlinfo = { 1670 .nlh = nlh, 1671 .nl_net = net, 1672 .portid = NETLINK_CB(skb).portid, 1673 }; 1674 struct nexthop *nh; 1675 int err; 1676 u32 id; 1677 1678 err = nh_valid_get_del_req(nlh, &id, extack); 1679 if (err) 1680 return err; 1681 1682 nh = nexthop_find_by_id(net, id); 1683 if (!nh) 1684 return -ENOENT; 1685 1686 remove_nexthop(net, nh, &nlinfo); 1687 1688 return 0; 1689 } 1690 1691 /* rtnl */ 1692 static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh, 1693 struct netlink_ext_ack *extack) 1694 { 1695 struct net *net = sock_net(in_skb->sk); 1696 struct sk_buff *skb = NULL; 1697 struct nexthop *nh; 1698 int err; 1699 u32 id; 1700 1701 err = nh_valid_get_del_req(nlh, &id, extack); 1702 if (err) 1703 return err; 1704 1705 err = -ENOBUFS; 1706 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 1707 if (!skb) 1708 goto out; 1709 1710 err = -ENOENT; 1711 nh = nexthop_find_by_id(net, id); 1712 if (!nh) 1713 goto errout_free; 1714 1715 err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid, 1716 nlh->nlmsg_seq, 0); 1717 if (err < 0) { 1718 WARN_ON(err == -EMSGSIZE); 1719 goto errout_free; 1720 } 1721 1722 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 1723 out: 1724 return err; 1725 errout_free: 1726 kfree_skb(skb); 1727 goto out; 1728 } 1729 1730 static bool nh_dump_filtered(struct nexthop *nh, int dev_idx, int master_idx, 1731 bool group_filter, u8 family) 1732 { 1733 const struct net_device *dev; 1734 const struct nh_info *nhi; 1735 1736 if (group_filter && !nh->is_group) 1737 return true; 1738 1739 if (!dev_idx && !master_idx && !family) 1740 return false; 1741 1742 if (nh->is_group) 1743 return true; 1744 1745 nhi = rtnl_dereference(nh->nh_info); 1746 if (family && nhi->family != family) 1747 return true; 1748 1749 dev = nhi->fib_nhc.nhc_dev; 1750 if (dev_idx && (!dev || dev->ifindex != dev_idx)) 1751 return true; 1752 1753 if (master_idx) { 1754 struct net_device *master; 1755 1756 if (!dev) 1757 return true; 1758 1759 master = netdev_master_upper_dev_get((struct net_device *)dev); 1760 if (!master || master->ifindex != master_idx) 1761 return true; 1762 } 1763 1764 return false; 1765 } 1766 1767 static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx, 1768 int *master_idx, bool *group_filter, 1769 bool *fdb_filter, struct netlink_callback *cb) 1770 { 1771 struct netlink_ext_ack *extack = cb->extack; 1772 struct nlattr *tb[NHA_MAX + 1]; 1773 struct nhmsg *nhm; 1774 int err, i; 1775 u32 idx; 1776 1777 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1778 NULL); 1779 if (err < 0) 1780 return err; 1781 1782 for (i = 0; i <= NHA_MAX; ++i) { 1783 if (!tb[i]) 1784 continue; 1785 1786 switch (i) { 1787 case NHA_OIF: 1788 idx = nla_get_u32(tb[i]); 1789 if (idx > INT_MAX) { 1790 NL_SET_ERR_MSG(extack, "Invalid device index"); 1791 return -EINVAL; 1792 } 1793 *dev_idx = idx; 1794 break; 1795 case NHA_MASTER: 1796 idx = nla_get_u32(tb[i]); 1797 if (idx > INT_MAX) { 1798 NL_SET_ERR_MSG(extack, "Invalid master device index"); 1799 return -EINVAL; 1800 } 1801 *master_idx = idx; 1802 break; 1803 case NHA_GROUPS: 1804 *group_filter = true; 1805 break; 1806 case NHA_FDB: 1807 *fdb_filter = true; 1808 break; 1809 default: 1810 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request"); 1811 return -EINVAL; 1812 } 1813 } 1814 1815 nhm = nlmsg_data(nlh); 1816 if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) { 1817 NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request"); 1818 return -EINVAL; 1819 } 1820 1821 return 0; 1822 } 1823 1824 /* rtnl */ 1825 static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb) 1826 { 1827 bool group_filter = false, fdb_filter = false; 1828 struct nhmsg *nhm = nlmsg_data(cb->nlh); 1829 int dev_filter_idx = 0, master_idx = 0; 1830 struct net *net = sock_net(skb->sk); 1831 struct rb_root *root = &net->nexthop.rb_root; 1832 struct rb_node *node; 1833 int idx = 0, s_idx; 1834 int err; 1835 1836 err = nh_valid_dump_req(cb->nlh, &dev_filter_idx, &master_idx, 1837 &group_filter, &fdb_filter, cb); 1838 if (err < 0) 1839 return err; 1840 1841 s_idx = cb->args[0]; 1842 for (node = rb_first(root); node; node = rb_next(node)) { 1843 struct nexthop *nh; 1844 1845 if (idx < s_idx) 1846 goto cont; 1847 1848 nh = rb_entry(node, struct nexthop, rb_node); 1849 if (nh_dump_filtered(nh, dev_filter_idx, master_idx, 1850 group_filter, nhm->nh_family)) 1851 goto cont; 1852 1853 err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, 1854 NETLINK_CB(cb->skb).portid, 1855 cb->nlh->nlmsg_seq, NLM_F_MULTI); 1856 if (err < 0) { 1857 if (likely(skb->len)) 1858 goto out; 1859 1860 goto out_err; 1861 } 1862 cont: 1863 idx++; 1864 } 1865 1866 out: 1867 err = skb->len; 1868 out_err: 1869 cb->args[0] = idx; 1870 cb->seq = net->nexthop.seq; 1871 nl_dump_check_consistent(cb, nlmsg_hdr(skb)); 1872 1873 return err; 1874 } 1875 1876 static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu) 1877 { 1878 unsigned int hash = nh_dev_hashfn(dev->ifindex); 1879 struct net *net = dev_net(dev); 1880 struct hlist_head *head = &net->nexthop.devhash[hash]; 1881 struct hlist_node *n; 1882 struct nh_info *nhi; 1883 1884 hlist_for_each_entry_safe(nhi, n, head, dev_hash) { 1885 if (nhi->fib_nhc.nhc_dev == dev) { 1886 if (nhi->family == AF_INET) 1887 fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu, 1888 orig_mtu); 1889 } 1890 } 1891 } 1892 1893 /* rtnl */ 1894 static int nh_netdev_event(struct notifier_block *this, 1895 unsigned long event, void *ptr) 1896 { 1897 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1898 struct netdev_notifier_info_ext *info_ext; 1899 1900 switch (event) { 1901 case NETDEV_DOWN: 1902 case NETDEV_UNREGISTER: 1903 nexthop_flush_dev(dev); 1904 break; 1905 case NETDEV_CHANGE: 1906 if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP))) 1907 nexthop_flush_dev(dev); 1908 break; 1909 case NETDEV_CHANGEMTU: 1910 info_ext = ptr; 1911 nexthop_sync_mtu(dev, info_ext->ext.mtu); 1912 rt_cache_flush(dev_net(dev)); 1913 break; 1914 } 1915 return NOTIFY_DONE; 1916 } 1917 1918 static struct notifier_block nh_netdev_notifier = { 1919 .notifier_call = nh_netdev_event, 1920 }; 1921 1922 int register_nexthop_notifier(struct net *net, struct notifier_block *nb) 1923 { 1924 return atomic_notifier_chain_register(&net->nexthop.notifier_chain, nb); 1925 } 1926 EXPORT_SYMBOL(register_nexthop_notifier); 1927 1928 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb) 1929 { 1930 return atomic_notifier_chain_unregister(&net->nexthop.notifier_chain, 1931 nb); 1932 } 1933 EXPORT_SYMBOL(unregister_nexthop_notifier); 1934 1935 static void __net_exit nexthop_net_exit(struct net *net) 1936 { 1937 rtnl_lock(); 1938 flush_all_nexthops(net); 1939 rtnl_unlock(); 1940 kfree(net->nexthop.devhash); 1941 } 1942 1943 static int __net_init nexthop_net_init(struct net *net) 1944 { 1945 size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE; 1946 1947 net->nexthop.rb_root = RB_ROOT; 1948 net->nexthop.devhash = kzalloc(sz, GFP_KERNEL); 1949 if (!net->nexthop.devhash) 1950 return -ENOMEM; 1951 ATOMIC_INIT_NOTIFIER_HEAD(&net->nexthop.notifier_chain); 1952 1953 return 0; 1954 } 1955 1956 static struct pernet_operations nexthop_net_ops = { 1957 .init = nexthop_net_init, 1958 .exit = nexthop_net_exit, 1959 }; 1960 1961 static int __init nexthop_init(void) 1962 { 1963 register_pernet_subsys(&nexthop_net_ops); 1964 1965 register_netdevice_notifier(&nh_netdev_notifier); 1966 1967 rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 1968 rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0); 1969 rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop, 1970 rtm_dump_nexthop, 0); 1971 1972 rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 1973 rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0); 1974 1975 rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 1976 rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0); 1977 1978 return 0; 1979 } 1980 subsys_initcall(nexthop_init); 1981