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 19static 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 25static 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 39static 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 = blocking_notifier_call_chain(&net->nexthop.notifier_chain, 46 event_type, nh); 47 return notifier_to_errno(err); 48} 49 50static 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 59static 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 72static 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 91static 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 107void 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} 118EXPORT_SYMBOL_GPL(nexthop_free_rcu); 119 120static 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 134static struct nh_group *nexthop_grp_alloc(u16 num_nh) 135{ 136 struct nh_group *nhg; 137 138 nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL); 139 if (nhg) 140 nhg->num_nh = num_nh; 141 142 return nhg; 143} 144 145static void nh_base_seq_inc(struct net *net) 146{ 147 while (++net->nexthop.seq == 0) 148 ; 149} 150 151/* no reference taken; rcu lock or rtnl must be held */ 152struct nexthop *nexthop_find_by_id(struct net *net, u32 id) 153{ 154 struct rb_node **pp, *parent = NULL, *next; 155 156 pp = &net->nexthop.rb_root.rb_node; 157 while (1) { 158 struct nexthop *nh; 159 160 next = rcu_dereference_raw(*pp); 161 if (!next) 162 break; 163 parent = next; 164 165 nh = rb_entry(parent, struct nexthop, rb_node); 166 if (id < nh->id) 167 pp = &next->rb_left; 168 else if (id > nh->id) 169 pp = &next->rb_right; 170 else 171 return nh; 172 } 173 return NULL; 174} 175EXPORT_SYMBOL_GPL(nexthop_find_by_id); 176 177/* used for auto id allocation; called with rtnl held */ 178static u32 nh_find_unused_id(struct net *net) 179{ 180 u32 id_start = net->nexthop.last_id_allocated; 181 182 while (1) { 183 net->nexthop.last_id_allocated++; 184 if (net->nexthop.last_id_allocated == id_start) 185 break; 186 187 if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated)) 188 return net->nexthop.last_id_allocated; 189 } 190 return 0; 191} 192 193static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg) 194{ 195 struct nexthop_grp *p; 196 size_t len = nhg->num_nh * sizeof(*p); 197 struct nlattr *nla; 198 u16 group_type = 0; 199 int i; 200 201 if (nhg->mpath) 202 group_type = NEXTHOP_GRP_TYPE_MPATH; 203 204 if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type)) 205 goto nla_put_failure; 206 207 nla = nla_reserve(skb, NHA_GROUP, len); 208 if (!nla) 209 goto nla_put_failure; 210 211 p = nla_data(nla); 212 for (i = 0; i < nhg->num_nh; ++i) { 213 *p++ = (struct nexthop_grp) { 214 .id = nhg->nh_entries[i].nh->id, 215 .weight = nhg->nh_entries[i].weight - 1, 216 }; 217 } 218 219 return 0; 220 221nla_put_failure: 222 return -EMSGSIZE; 223} 224 225static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh, 226 int event, u32 portid, u32 seq, unsigned int nlflags) 227{ 228 struct fib6_nh *fib6_nh; 229 struct fib_nh *fib_nh; 230 struct nlmsghdr *nlh; 231 struct nh_info *nhi; 232 struct nhmsg *nhm; 233 234 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags); 235 if (!nlh) 236 return -EMSGSIZE; 237 238 nhm = nlmsg_data(nlh); 239 nhm->nh_family = AF_UNSPEC; 240 nhm->nh_flags = nh->nh_flags; 241 nhm->nh_protocol = nh->protocol; 242 nhm->nh_scope = 0; 243 nhm->resvd = 0; 244 245 if (nla_put_u32(skb, NHA_ID, nh->id)) 246 goto nla_put_failure; 247 248 if (nh->is_group) { 249 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 250 251 if (nhg->fdb_nh && nla_put_flag(skb, NHA_FDB)) 252 goto nla_put_failure; 253 if (nla_put_nh_group(skb, nhg)) 254 goto nla_put_failure; 255 goto out; 256 } 257 258 nhi = rtnl_dereference(nh->nh_info); 259 nhm->nh_family = nhi->family; 260 if (nhi->reject_nh) { 261 if (nla_put_flag(skb, NHA_BLACKHOLE)) 262 goto nla_put_failure; 263 goto out; 264 } else if (nhi->fdb_nh) { 265 if (nla_put_flag(skb, NHA_FDB)) 266 goto nla_put_failure; 267 } else { 268 const struct net_device *dev; 269 270 dev = nhi->fib_nhc.nhc_dev; 271 if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex)) 272 goto nla_put_failure; 273 } 274 275 nhm->nh_scope = nhi->fib_nhc.nhc_scope; 276 switch (nhi->family) { 277 case AF_INET: 278 fib_nh = &nhi->fib_nh; 279 if (fib_nh->fib_nh_gw_family && 280 nla_put_be32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4)) 281 goto nla_put_failure; 282 break; 283 284 case AF_INET6: 285 fib6_nh = &nhi->fib6_nh; 286 if (fib6_nh->fib_nh_gw_family && 287 nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6)) 288 goto nla_put_failure; 289 break; 290 } 291 292 if (nhi->fib_nhc.nhc_lwtstate && 293 lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate, 294 NHA_ENCAP, NHA_ENCAP_TYPE) < 0) 295 goto nla_put_failure; 296 297out: 298 nlmsg_end(skb, nlh); 299 return 0; 300 301nla_put_failure: 302 nlmsg_cancel(skb, nlh); 303 return -EMSGSIZE; 304} 305 306static size_t nh_nlmsg_size_grp(struct nexthop *nh) 307{ 308 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 309 size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh; 310 311 return nla_total_size(sz) + 312 nla_total_size(2); /* NHA_GROUP_TYPE */ 313} 314 315static size_t nh_nlmsg_size_single(struct nexthop *nh) 316{ 317 struct nh_info *nhi = rtnl_dereference(nh->nh_info); 318 size_t sz; 319 320 /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE 321 * are mutually exclusive 322 */ 323 sz = nla_total_size(4); /* NHA_OIF */ 324 325 switch (nhi->family) { 326 case AF_INET: 327 if (nhi->fib_nh.fib_nh_gw_family) 328 sz += nla_total_size(4); /* NHA_GATEWAY */ 329 break; 330 331 case AF_INET6: 332 /* NHA_GATEWAY */ 333 if (nhi->fib6_nh.fib_nh_gw_family) 334 sz += nla_total_size(sizeof(const struct in6_addr)); 335 break; 336 } 337 338 if (nhi->fib_nhc.nhc_lwtstate) { 339 sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate); 340 sz += nla_total_size(2); /* NHA_ENCAP_TYPE */ 341 } 342 343 return sz; 344} 345 346static size_t nh_nlmsg_size(struct nexthop *nh) 347{ 348 size_t sz = NLMSG_ALIGN(sizeof(struct nhmsg)); 349 350 sz += nla_total_size(4); /* NHA_ID */ 351 352 if (nh->is_group) 353 sz += nh_nlmsg_size_grp(nh); 354 else 355 sz += nh_nlmsg_size_single(nh); 356 357 return sz; 358} 359 360static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info) 361{ 362 unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0; 363 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; 364 struct sk_buff *skb; 365 int err = -ENOBUFS; 366 367 skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any()); 368 if (!skb) 369 goto errout; 370 371 err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags); 372 if (err < 0) { 373 /* -EMSGSIZE implies BUG in nh_nlmsg_size() */ 374 WARN_ON(err == -EMSGSIZE); 375 kfree_skb(skb); 376 goto errout; 377 } 378 379 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP, 380 info->nlh, gfp_any()); 381 return; 382errout: 383 if (err < 0) 384 rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err); 385} 386 387static bool valid_group_nh(struct nexthop *nh, unsigned int npaths, 388 bool *is_fdb, struct netlink_ext_ack *extack) 389{ 390 if (nh->is_group) { 391 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 392 393 /* nested multipath (group within a group) is not 394 * supported 395 */ 396 if (nhg->mpath) { 397 NL_SET_ERR_MSG(extack, 398 "Multipath group can not be a nexthop within a group"); 399 return false; 400 } 401 *is_fdb = nhg->fdb_nh; 402 } else { 403 struct nh_info *nhi = rtnl_dereference(nh->nh_info); 404 405 if (nhi->reject_nh && npaths > 1) { 406 NL_SET_ERR_MSG(extack, 407 "Blackhole nexthop can not be used in a group with more than 1 path"); 408 return false; 409 } 410 *is_fdb = nhi->fdb_nh; 411 } 412 413 return true; 414} 415 416static int nh_check_attr_fdb_group(struct nexthop *nh, u8 *nh_family, 417 struct netlink_ext_ack *extack) 418{ 419 struct nh_info *nhi; 420 421 nhi = rtnl_dereference(nh->nh_info); 422 423 if (!nhi->fdb_nh) { 424 NL_SET_ERR_MSG(extack, "FDB nexthop group can only have fdb nexthops"); 425 return -EINVAL; 426 } 427 428 if (*nh_family == AF_UNSPEC) { 429 *nh_family = nhi->family; 430 } else if (*nh_family != nhi->family) { 431 NL_SET_ERR_MSG(extack, "FDB nexthop group cannot have mixed family nexthops"); 432 return -EINVAL; 433 } 434 435 return 0; 436} 437 438static int nh_check_attr_group(struct net *net, struct nlattr *tb[], 439 struct netlink_ext_ack *extack) 440{ 441 unsigned int len = nla_len(tb[NHA_GROUP]); 442 u8 nh_family = AF_UNSPEC; 443 struct nexthop_grp *nhg; 444 unsigned int i, j; 445 u8 nhg_fdb = 0; 446 447 if (!len || len & (sizeof(struct nexthop_grp) - 1)) { 448 NL_SET_ERR_MSG(extack, 449 "Invalid length for nexthop group attribute"); 450 return -EINVAL; 451 } 452 453 /* convert len to number of nexthop ids */ 454 len /= sizeof(*nhg); 455 456 nhg = nla_data(tb[NHA_GROUP]); 457 for (i = 0; i < len; ++i) { 458 if (nhg[i].resvd1 || nhg[i].resvd2) { 459 NL_SET_ERR_MSG(extack, "Reserved fields in nexthop_grp must be 0"); 460 return -EINVAL; 461 } 462 if (nhg[i].weight > 254) { 463 NL_SET_ERR_MSG(extack, "Invalid value for weight"); 464 return -EINVAL; 465 } 466 for (j = i + 1; j < len; ++j) { 467 if (nhg[i].id == nhg[j].id) { 468 NL_SET_ERR_MSG(extack, "Nexthop id can not be used twice in a group"); 469 return -EINVAL; 470 } 471 } 472 } 473 474 if (tb[NHA_FDB]) 475 nhg_fdb = 1; 476 nhg = nla_data(tb[NHA_GROUP]); 477 for (i = 0; i < len; ++i) { 478 struct nexthop *nh; 479 bool is_fdb_nh; 480 481 nh = nexthop_find_by_id(net, nhg[i].id); 482 if (!nh) { 483 NL_SET_ERR_MSG(extack, "Invalid nexthop id"); 484 return -EINVAL; 485 } 486 if (!valid_group_nh(nh, len, &is_fdb_nh, extack)) 487 return -EINVAL; 488 489 if (nhg_fdb && nh_check_attr_fdb_group(nh, &nh_family, extack)) 490 return -EINVAL; 491 492 if (!nhg_fdb && is_fdb_nh) { 493 NL_SET_ERR_MSG(extack, "Non FDB nexthop group cannot have fdb nexthops"); 494 return -EINVAL; 495 } 496 } 497 for (i = NHA_GROUP_TYPE + 1; i < __NHA_MAX; ++i) { 498 if (!tb[i]) 499 continue; 500 if (i == NHA_FDB) 501 continue; 502 NL_SET_ERR_MSG(extack, 503 "No other attributes can be set in nexthop groups"); 504 return -EINVAL; 505 } 506 507 return 0; 508} 509 510static bool ipv6_good_nh(const struct fib6_nh *nh) 511{ 512 int state = NUD_REACHABLE; 513 struct neighbour *n; 514 515 rcu_read_lock_bh(); 516 517 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6); 518 if (n) 519 state = n->nud_state; 520 521 rcu_read_unlock_bh(); 522 523 return !!(state & NUD_VALID); 524} 525 526static bool ipv4_good_nh(const struct fib_nh *nh) 527{ 528 int state = NUD_REACHABLE; 529 struct neighbour *n; 530 531 rcu_read_lock_bh(); 532 533 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, 534 (__force u32)nh->fib_nh_gw4); 535 if (n) 536 state = n->nud_state; 537 538 rcu_read_unlock_bh(); 539 540 return !!(state & NUD_VALID); 541} 542 543struct nexthop *nexthop_select_path(struct nexthop *nh, int hash) 544{ 545 struct nexthop *rc = NULL; 546 struct nh_group *nhg; 547 int i; 548 549 if (!nh->is_group) 550 return nh; 551 552 nhg = rcu_dereference(nh->nh_grp); 553 for (i = 0; i < nhg->num_nh; ++i) { 554 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 555 struct nh_info *nhi; 556 557 if (hash > atomic_read(&nhge->upper_bound)) 558 continue; 559 560 nhi = rcu_dereference(nhge->nh->nh_info); 561 if (nhi->fdb_nh) 562 return nhge->nh; 563 564 /* nexthops always check if it is good and does 565 * not rely on a sysctl for this behavior 566 */ 567 switch (nhi->family) { 568 case AF_INET: 569 if (ipv4_good_nh(&nhi->fib_nh)) 570 return nhge->nh; 571 break; 572 case AF_INET6: 573 if (ipv6_good_nh(&nhi->fib6_nh)) 574 return nhge->nh; 575 break; 576 } 577 578 if (!rc) 579 rc = nhge->nh; 580 } 581 582 return rc; 583} 584EXPORT_SYMBOL_GPL(nexthop_select_path); 585 586int nexthop_for_each_fib6_nh(struct nexthop *nh, 587 int (*cb)(struct fib6_nh *nh, void *arg), 588 void *arg) 589{ 590 struct nh_info *nhi; 591 int err; 592 593 if (nh->is_group) { 594 struct nh_group *nhg; 595 int i; 596 597 nhg = rcu_dereference_rtnl(nh->nh_grp); 598 for (i = 0; i < nhg->num_nh; i++) { 599 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 600 601 nhi = rcu_dereference_rtnl(nhge->nh->nh_info); 602 err = cb(&nhi->fib6_nh, arg); 603 if (err) 604 return err; 605 } 606 } else { 607 nhi = rcu_dereference_rtnl(nh->nh_info); 608 err = cb(&nhi->fib6_nh, arg); 609 if (err) 610 return err; 611 } 612 613 return 0; 614} 615EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh); 616 617static int check_src_addr(const struct in6_addr *saddr, 618 struct netlink_ext_ack *extack) 619{ 620 if (!ipv6_addr_any(saddr)) { 621 NL_SET_ERR_MSG(extack, "IPv6 routes using source address can not use nexthop objects"); 622 return -EINVAL; 623 } 624 return 0; 625} 626 627int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg, 628 struct netlink_ext_ack *extack) 629{ 630 struct nh_info *nhi; 631 bool is_fdb_nh; 632 633 /* fib6_src is unique to a fib6_info and limits the ability to cache 634 * routes in fib6_nh within a nexthop that is potentially shared 635 * across multiple fib entries. If the config wants to use source 636 * routing it can not use nexthop objects. mlxsw also does not allow 637 * fib6_src on routes. 638 */ 639 if (cfg && check_src_addr(&cfg->fc_src, extack) < 0) 640 return -EINVAL; 641 642 if (nh->is_group) { 643 struct nh_group *nhg; 644 645 nhg = rtnl_dereference(nh->nh_grp); 646 if (nhg->has_v4) 647 goto no_v4_nh; 648 is_fdb_nh = nhg->fdb_nh; 649 } else { 650 nhi = rtnl_dereference(nh->nh_info); 651 if (nhi->family == AF_INET) 652 goto no_v4_nh; 653 is_fdb_nh = nhi->fdb_nh; 654 } 655 656 if (is_fdb_nh) { 657 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 658 return -EINVAL; 659 } 660 661 return 0; 662no_v4_nh: 663 NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop"); 664 return -EINVAL; 665} 666EXPORT_SYMBOL_GPL(fib6_check_nexthop); 667 668/* if existing nexthop has ipv6 routes linked to it, need 669 * to verify this new spec works with ipv6 670 */ 671static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new, 672 struct netlink_ext_ack *extack) 673{ 674 struct fib6_info *f6i; 675 676 if (list_empty(&old->f6i_list)) 677 return 0; 678 679 list_for_each_entry(f6i, &old->f6i_list, nh_list) { 680 if (check_src_addr(&f6i->fib6_src.addr, extack) < 0) 681 return -EINVAL; 682 } 683 684 return fib6_check_nexthop(new, NULL, extack); 685} 686 687static int nexthop_check_scope(struct nh_info *nhi, u8 scope, 688 struct netlink_ext_ack *extack) 689{ 690 if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) { 691 NL_SET_ERR_MSG(extack, 692 "Route with host scope can not have a gateway"); 693 return -EINVAL; 694 } 695 696 if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) { 697 NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop"); 698 return -EINVAL; 699 } 700 701 return 0; 702} 703 704/* Invoked by fib add code to verify nexthop by id is ok with 705 * config for prefix; parts of fib_check_nh not done when nexthop 706 * object is used. 707 */ 708int fib_check_nexthop(struct nexthop *nh, u8 scope, 709 struct netlink_ext_ack *extack) 710{ 711 struct nh_info *nhi; 712 int err = 0; 713 714 if (nh->is_group) { 715 struct nh_group *nhg; 716 717 nhg = rtnl_dereference(nh->nh_grp); 718 if (nhg->fdb_nh) { 719 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 720 err = -EINVAL; 721 goto out; 722 } 723 724 if (scope == RT_SCOPE_HOST) { 725 NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops"); 726 err = -EINVAL; 727 goto out; 728 } 729 730 /* all nexthops in a group have the same scope */ 731 nhi = rtnl_dereference(nhg->nh_entries[0].nh->nh_info); 732 err = nexthop_check_scope(nhi, scope, extack); 733 } else { 734 nhi = rtnl_dereference(nh->nh_info); 735 if (nhi->fdb_nh) { 736 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop"); 737 err = -EINVAL; 738 goto out; 739 } 740 err = nexthop_check_scope(nhi, scope, extack); 741 } 742 743out: 744 return err; 745} 746 747static int fib_check_nh_list(struct nexthop *old, struct nexthop *new, 748 struct netlink_ext_ack *extack) 749{ 750 struct fib_info *fi; 751 752 list_for_each_entry(fi, &old->fi_list, nh_list) { 753 int err; 754 755 err = fib_check_nexthop(new, fi->fib_scope, extack); 756 if (err) 757 return err; 758 } 759 return 0; 760} 761 762static void nh_group_rebalance(struct nh_group *nhg) 763{ 764 int total = 0; 765 int w = 0; 766 int i; 767 768 for (i = 0; i < nhg->num_nh; ++i) 769 total += nhg->nh_entries[i].weight; 770 771 for (i = 0; i < nhg->num_nh; ++i) { 772 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 773 int upper_bound; 774 775 w += nhge->weight; 776 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1; 777 atomic_set(&nhge->upper_bound, upper_bound); 778 } 779} 780 781static void remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge, 782 struct nl_info *nlinfo) 783{ 784 struct nh_grp_entry *nhges, *new_nhges; 785 struct nexthop *nhp = nhge->nh_parent; 786 struct nexthop *nh = nhge->nh; 787 struct nh_group *nhg, *newg; 788 int i, j; 789 790 WARN_ON(!nh); 791 792 nhg = rtnl_dereference(nhp->nh_grp); 793 newg = nhg->spare; 794 795 /* last entry, keep it visible and remove the parent */ 796 if (nhg->num_nh == 1) { 797 remove_nexthop(net, nhp, nlinfo); 798 return; 799 } 800 801 newg->has_v4 = false; 802 newg->mpath = nhg->mpath; 803 newg->fdb_nh = nhg->fdb_nh; 804 newg->num_nh = nhg->num_nh; 805 806 /* copy old entries to new except the one getting removed */ 807 nhges = nhg->nh_entries; 808 new_nhges = newg->nh_entries; 809 for (i = 0, j = 0; i < nhg->num_nh; ++i) { 810 struct nh_info *nhi; 811 812 /* current nexthop getting removed */ 813 if (nhg->nh_entries[i].nh == nh) { 814 newg->num_nh--; 815 continue; 816 } 817 818 nhi = rtnl_dereference(nhges[i].nh->nh_info); 819 if (nhi->family == AF_INET) 820 newg->has_v4 = true; 821 822 list_del(&nhges[i].nh_list); 823 new_nhges[j].nh_parent = nhges[i].nh_parent; 824 new_nhges[j].nh = nhges[i].nh; 825 new_nhges[j].weight = nhges[i].weight; 826 list_add(&new_nhges[j].nh_list, &new_nhges[j].nh->grp_list); 827 j++; 828 } 829 830 nh_group_rebalance(newg); 831 rcu_assign_pointer(nhp->nh_grp, newg); 832 833 list_del(&nhge->nh_list); 834 nexthop_put(nhge->nh); 835 836 if (nlinfo) 837 nexthop_notify(RTM_NEWNEXTHOP, nhp, nlinfo); 838} 839 840static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh, 841 struct nl_info *nlinfo) 842{ 843 struct nh_grp_entry *nhge, *tmp; 844 845 list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list) 846 remove_nh_grp_entry(net, nhge, nlinfo); 847 848 /* make sure all see the newly published array before releasing rtnl */ 849 synchronize_net(); 850} 851 852static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo) 853{ 854 struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp); 855 int i, num_nh = nhg->num_nh; 856 857 for (i = 0; i < num_nh; ++i) { 858 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 859 860 if (WARN_ON(!nhge->nh)) 861 continue; 862 863 list_del_init(&nhge->nh_list); 864 } 865} 866 867/* not called for nexthop replace */ 868static void __remove_nexthop_fib(struct net *net, struct nexthop *nh) 869{ 870 struct fib6_info *f6i, *tmp; 871 bool do_flush = false; 872 struct fib_info *fi; 873 874 list_for_each_entry(fi, &nh->fi_list, nh_list) { 875 fi->fib_flags |= RTNH_F_DEAD; 876 do_flush = true; 877 } 878 if (do_flush) 879 fib_flush(net); 880 881 /* ip6_del_rt removes the entry from this list hence the _safe */ 882 list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) { 883 /* __ip6_del_rt does a release, so do a hold here */ 884 fib6_info_hold(f6i); 885 ipv6_stub->ip6_del_rt(net, f6i, 886 !READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode)); 887 } 888} 889 890static void __remove_nexthop(struct net *net, struct nexthop *nh, 891 struct nl_info *nlinfo) 892{ 893 __remove_nexthop_fib(net, nh); 894 895 if (nh->is_group) { 896 remove_nexthop_group(nh, nlinfo); 897 } else { 898 struct nh_info *nhi; 899 900 nhi = rtnl_dereference(nh->nh_info); 901 if (nhi->fib_nhc.nhc_dev) 902 hlist_del(&nhi->dev_hash); 903 904 remove_nexthop_from_groups(net, nh, nlinfo); 905 } 906} 907 908static void remove_nexthop(struct net *net, struct nexthop *nh, 909 struct nl_info *nlinfo) 910{ 911 call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh); 912 913 /* remove from the tree */ 914 rb_erase(&nh->rb_node, &net->nexthop.rb_root); 915 916 if (nlinfo) 917 nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo); 918 919 __remove_nexthop(net, nh, nlinfo); 920 nh_base_seq_inc(net); 921 922 nexthop_put(nh); 923} 924 925/* if any FIB entries reference this nexthop, any dst entries 926 * need to be regenerated 927 */ 928static void nh_rt_cache_flush(struct net *net, struct nexthop *nh, 929 struct nexthop *replaced_nh) 930{ 931 struct fib6_info *f6i; 932 struct nh_group *nhg; 933 int i; 934 935 if (!list_empty(&nh->fi_list)) 936 rt_cache_flush(net); 937 938 list_for_each_entry(f6i, &nh->f6i_list, nh_list) 939 ipv6_stub->fib6_update_sernum(net, f6i); 940 941 /* if an IPv6 group was replaced, we have to release all old 942 * dsts to make sure all refcounts are released 943 */ 944 if (!replaced_nh->is_group) 945 return; 946 947 /* new dsts must use only the new nexthop group */ 948 synchronize_net(); 949 950 nhg = rtnl_dereference(replaced_nh->nh_grp); 951 for (i = 0; i < nhg->num_nh; i++) { 952 struct nh_grp_entry *nhge = &nhg->nh_entries[i]; 953 struct nh_info *nhi = rtnl_dereference(nhge->nh->nh_info); 954 955 if (nhi->family == AF_INET6) 956 ipv6_stub->fib6_nh_release_dsts(&nhi->fib6_nh); 957 } 958} 959 960static int replace_nexthop_grp(struct net *net, struct nexthop *old, 961 struct nexthop *new, 962 struct netlink_ext_ack *extack) 963{ 964 struct nh_group *oldg, *newg; 965 int i; 966 967 if (!new->is_group) { 968 NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a nexthop."); 969 return -EINVAL; 970 } 971 972 oldg = rtnl_dereference(old->nh_grp); 973 newg = rtnl_dereference(new->nh_grp); 974 975 /* update parents - used by nexthop code for cleanup */ 976 for (i = 0; i < newg->num_nh; i++) 977 newg->nh_entries[i].nh_parent = old; 978 979 rcu_assign_pointer(old->nh_grp, newg); 980 981 for (i = 0; i < oldg->num_nh; i++) 982 oldg->nh_entries[i].nh_parent = new; 983 984 rcu_assign_pointer(new->nh_grp, oldg); 985 986 return 0; 987} 988 989static void nh_group_v4_update(struct nh_group *nhg) 990{ 991 struct nh_grp_entry *nhges; 992 bool has_v4 = false; 993 int i; 994 995 nhges = nhg->nh_entries; 996 for (i = 0; i < nhg->num_nh; i++) { 997 struct nh_info *nhi; 998 999 nhi = rtnl_dereference(nhges[i].nh->nh_info); 1000 if (nhi->family == AF_INET) 1001 has_v4 = true; 1002 } 1003 nhg->has_v4 = has_v4; 1004} 1005 1006static int replace_nexthop_single(struct net *net, struct nexthop *old, 1007 struct nexthop *new, 1008 struct netlink_ext_ack *extack) 1009{ 1010 struct nh_info *oldi, *newi; 1011 1012 if (new->is_group) { 1013 NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a nexthop group."); 1014 return -EINVAL; 1015 } 1016 1017 oldi = rtnl_dereference(old->nh_info); 1018 newi = rtnl_dereference(new->nh_info); 1019 1020 newi->nh_parent = old; 1021 oldi->nh_parent = new; 1022 1023 old->protocol = new->protocol; 1024 old->nh_flags = new->nh_flags; 1025 1026 rcu_assign_pointer(old->nh_info, newi); 1027 rcu_assign_pointer(new->nh_info, oldi); 1028 1029 /* When replacing an IPv4 nexthop with an IPv6 nexthop, potentially 1030 * update IPv4 indication in all the groups using the nexthop. 1031 */ 1032 if (oldi->family == AF_INET && newi->family == AF_INET6) { 1033 struct nh_grp_entry *nhge; 1034 1035 list_for_each_entry(nhge, &old->grp_list, nh_list) { 1036 struct nexthop *nhp = nhge->nh_parent; 1037 struct nh_group *nhg; 1038 1039 nhg = rtnl_dereference(nhp->nh_grp); 1040 nh_group_v4_update(nhg); 1041 } 1042 } 1043 1044 return 0; 1045} 1046 1047static void __nexthop_replace_notify(struct net *net, struct nexthop *nh, 1048 struct nl_info *info) 1049{ 1050 struct fib6_info *f6i; 1051 1052 if (!list_empty(&nh->fi_list)) { 1053 struct fib_info *fi; 1054 1055 /* expectation is a few fib_info per nexthop and then 1056 * a lot of routes per fib_info. So mark the fib_info 1057 * and then walk the fib tables once 1058 */ 1059 list_for_each_entry(fi, &nh->fi_list, nh_list) 1060 fi->nh_updated = true; 1061 1062 fib_info_notify_update(net, info); 1063 1064 list_for_each_entry(fi, &nh->fi_list, nh_list) 1065 fi->nh_updated = false; 1066 } 1067 1068 list_for_each_entry(f6i, &nh->f6i_list, nh_list) 1069 ipv6_stub->fib6_rt_update(net, f6i, info); 1070} 1071 1072/* send RTM_NEWROUTE with REPLACE flag set for all FIB entries 1073 * linked to this nexthop and for all groups that the nexthop 1074 * is a member of 1075 */ 1076static void nexthop_replace_notify(struct net *net, struct nexthop *nh, 1077 struct nl_info *info) 1078{ 1079 struct nh_grp_entry *nhge; 1080 1081 __nexthop_replace_notify(net, nh, info); 1082 1083 list_for_each_entry(nhge, &nh->grp_list, nh_list) 1084 __nexthop_replace_notify(net, nhge->nh_parent, info); 1085} 1086 1087static int replace_nexthop(struct net *net, struct nexthop *old, 1088 struct nexthop *new, struct netlink_ext_ack *extack) 1089{ 1090 bool new_is_reject = false; 1091 struct nh_grp_entry *nhge; 1092 int err; 1093 1094 /* check that existing FIB entries are ok with the 1095 * new nexthop definition 1096 */ 1097 err = fib_check_nh_list(old, new, extack); 1098 if (err) 1099 return err; 1100 1101 err = fib6_check_nh_list(old, new, extack); 1102 if (err) 1103 return err; 1104 1105 if (!new->is_group) { 1106 struct nh_info *nhi = rtnl_dereference(new->nh_info); 1107 1108 new_is_reject = nhi->reject_nh; 1109 } 1110 1111 list_for_each_entry(nhge, &old->grp_list, nh_list) { 1112 /* if new nexthop is a blackhole, any groups using this 1113 * nexthop cannot have more than 1 path 1114 */ 1115 if (new_is_reject && 1116 nexthop_num_path(nhge->nh_parent) > 1) { 1117 NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a member of a group with more than one path"); 1118 return -EINVAL; 1119 } 1120 1121 err = fib_check_nh_list(nhge->nh_parent, new, extack); 1122 if (err) 1123 return err; 1124 1125 err = fib6_check_nh_list(nhge->nh_parent, new, extack); 1126 if (err) 1127 return err; 1128 } 1129 1130 if (old->is_group) 1131 err = replace_nexthop_grp(net, old, new, extack); 1132 else 1133 err = replace_nexthop_single(net, old, new, extack); 1134 1135 if (!err) { 1136 nh_rt_cache_flush(net, old, new); 1137 1138 __remove_nexthop(net, new, NULL); 1139 nexthop_put(new); 1140 } 1141 1142 return err; 1143} 1144 1145/* called with rtnl_lock held */ 1146static int insert_nexthop(struct net *net, struct nexthop *new_nh, 1147 struct nh_config *cfg, struct netlink_ext_ack *extack) 1148{ 1149 struct rb_node **pp, *parent = NULL, *next; 1150 struct rb_root *root = &net->nexthop.rb_root; 1151 bool replace = !!(cfg->nlflags & NLM_F_REPLACE); 1152 bool create = !!(cfg->nlflags & NLM_F_CREATE); 1153 u32 new_id = new_nh->id; 1154 int replace_notify = 0; 1155 int rc = -EEXIST; 1156 1157 pp = &root->rb_node; 1158 while (1) { 1159 struct nexthop *nh; 1160 1161 next = *pp; 1162 if (!next) 1163 break; 1164 1165 parent = next; 1166 1167 nh = rb_entry(parent, struct nexthop, rb_node); 1168 if (new_id < nh->id) { 1169 pp = &next->rb_left; 1170 } else if (new_id > nh->id) { 1171 pp = &next->rb_right; 1172 } else if (replace) { 1173 rc = replace_nexthop(net, nh, new_nh, extack); 1174 if (!rc) { 1175 new_nh = nh; /* send notification with old nh */ 1176 replace_notify = 1; 1177 } 1178 goto out; 1179 } else { 1180 /* id already exists and not a replace */ 1181 goto out; 1182 } 1183 } 1184 1185 if (replace && !create) { 1186 NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists"); 1187 rc = -ENOENT; 1188 goto out; 1189 } 1190 1191 rb_link_node_rcu(&new_nh->rb_node, parent, pp); 1192 rb_insert_color(&new_nh->rb_node, root); 1193 rc = 0; 1194out: 1195 if (!rc) { 1196 nh_base_seq_inc(net); 1197 nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo); 1198 if (replace_notify && 1199 READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode)) 1200 nexthop_replace_notify(net, new_nh, &cfg->nlinfo); 1201 } 1202 1203 return rc; 1204} 1205 1206/* rtnl */ 1207/* remove all nexthops tied to a device being deleted */ 1208static void nexthop_flush_dev(struct net_device *dev, unsigned long event) 1209{ 1210 unsigned int hash = nh_dev_hashfn(dev->ifindex); 1211 struct net *net = dev_net(dev); 1212 struct hlist_head *head = &net->nexthop.devhash[hash]; 1213 struct hlist_node *n; 1214 struct nh_info *nhi; 1215 1216 hlist_for_each_entry_safe(nhi, n, head, dev_hash) { 1217 if (nhi->fib_nhc.nhc_dev != dev) 1218 continue; 1219 1220 if (nhi->reject_nh && 1221 (event == NETDEV_DOWN || event == NETDEV_CHANGE)) 1222 continue; 1223 1224 remove_nexthop(net, nhi->nh_parent, NULL); 1225 } 1226} 1227 1228/* rtnl; called when net namespace is deleted */ 1229static void flush_all_nexthops(struct net *net) 1230{ 1231 struct rb_root *root = &net->nexthop.rb_root; 1232 struct rb_node *node; 1233 struct nexthop *nh; 1234 1235 while ((node = rb_first(root))) { 1236 nh = rb_entry(node, struct nexthop, rb_node); 1237 remove_nexthop(net, nh, NULL); 1238 cond_resched(); 1239 } 1240} 1241 1242static struct nexthop *nexthop_create_group(struct net *net, 1243 struct nh_config *cfg) 1244{ 1245 struct nlattr *grps_attr = cfg->nh_grp; 1246 struct nexthop_grp *entry = nla_data(grps_attr); 1247 u16 num_nh = nla_len(grps_attr) / sizeof(*entry); 1248 struct nh_group *nhg; 1249 struct nexthop *nh; 1250 int i; 1251 1252 if (WARN_ON(!num_nh)) 1253 return ERR_PTR(-EINVAL); 1254 1255 nh = nexthop_alloc(); 1256 if (!nh) 1257 return ERR_PTR(-ENOMEM); 1258 1259 nh->is_group = 1; 1260 1261 nhg = nexthop_grp_alloc(num_nh); 1262 if (!nhg) { 1263 kfree(nh); 1264 return ERR_PTR(-ENOMEM); 1265 } 1266 1267 /* spare group used for removals */ 1268 nhg->spare = nexthop_grp_alloc(num_nh); 1269 if (!nhg->spare) { 1270 kfree(nhg); 1271 kfree(nh); 1272 return ERR_PTR(-ENOMEM); 1273 } 1274 nhg->spare->spare = nhg; 1275 1276 for (i = 0; i < nhg->num_nh; ++i) { 1277 struct nexthop *nhe; 1278 struct nh_info *nhi; 1279 1280 nhe = nexthop_find_by_id(net, entry[i].id); 1281 if (!nexthop_get(nhe)) 1282 goto out_no_nh; 1283 1284 nhi = rtnl_dereference(nhe->nh_info); 1285 if (nhi->family == AF_INET) 1286 nhg->has_v4 = true; 1287 1288 nhg->nh_entries[i].nh = nhe; 1289 nhg->nh_entries[i].weight = entry[i].weight + 1; 1290 list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list); 1291 nhg->nh_entries[i].nh_parent = nh; 1292 } 1293 1294 if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) { 1295 nhg->mpath = 1; 1296 nh_group_rebalance(nhg); 1297 } 1298 1299 if (cfg->nh_fdb) 1300 nhg->fdb_nh = 1; 1301 1302 rcu_assign_pointer(nh->nh_grp, nhg); 1303 1304 return nh; 1305 1306out_no_nh: 1307 for (i--; i >= 0; --i) { 1308 list_del(&nhg->nh_entries[i].nh_list); 1309 nexthop_put(nhg->nh_entries[i].nh); 1310 } 1311 1312 kfree(nhg->spare); 1313 kfree(nhg); 1314 kfree(nh); 1315 1316 return ERR_PTR(-ENOENT); 1317} 1318 1319static int nh_create_ipv4(struct net *net, struct nexthop *nh, 1320 struct nh_info *nhi, struct nh_config *cfg, 1321 struct netlink_ext_ack *extack) 1322{ 1323 struct fib_nh *fib_nh = &nhi->fib_nh; 1324 struct fib_config fib_cfg = { 1325 .fc_oif = cfg->nh_ifindex, 1326 .fc_gw4 = cfg->gw.ipv4, 1327 .fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0, 1328 .fc_flags = cfg->nh_flags, 1329 .fc_nlinfo = cfg->nlinfo, 1330 .fc_encap = cfg->nh_encap, 1331 .fc_encap_type = cfg->nh_encap_type, 1332 }; 1333 u32 tb_id = (cfg->dev ? l3mdev_fib_table(cfg->dev) : RT_TABLE_MAIN); 1334 int err; 1335 1336 err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack); 1337 if (err) { 1338 fib_nh_release(net, fib_nh); 1339 goto out; 1340 } 1341 1342 if (nhi->fdb_nh) 1343 goto out; 1344 1345 /* sets nh_dev if successful */ 1346 err = fib_check_nh(net, fib_nh, tb_id, 0, extack); 1347 if (!err) { 1348 nh->nh_flags = fib_nh->fib_nh_flags; 1349 fib_info_update_nhc_saddr(net, &fib_nh->nh_common, 1350 !fib_nh->fib_nh_scope ? 0 : fib_nh->fib_nh_scope - 1); 1351 } else { 1352 fib_nh_release(net, fib_nh); 1353 } 1354out: 1355 return err; 1356} 1357 1358static int nh_create_ipv6(struct net *net, struct nexthop *nh, 1359 struct nh_info *nhi, struct nh_config *cfg, 1360 struct netlink_ext_ack *extack) 1361{ 1362 struct fib6_nh *fib6_nh = &nhi->fib6_nh; 1363 struct fib6_config fib6_cfg = { 1364 .fc_table = l3mdev_fib_table(cfg->dev), 1365 .fc_ifindex = cfg->nh_ifindex, 1366 .fc_gateway = cfg->gw.ipv6, 1367 .fc_flags = cfg->nh_flags, 1368 .fc_nlinfo = cfg->nlinfo, 1369 .fc_encap = cfg->nh_encap, 1370 .fc_encap_type = cfg->nh_encap_type, 1371 .fc_is_fdb = cfg->nh_fdb, 1372 }; 1373 int err; 1374 1375 if (!ipv6_addr_any(&cfg->gw.ipv6)) 1376 fib6_cfg.fc_flags |= RTF_GATEWAY; 1377 1378 /* sets nh_dev if successful */ 1379 err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL, 1380 extack); 1381 if (err) { 1382 /* IPv6 is not enabled, don't call fib6_nh_release */ 1383 if (err == -EAFNOSUPPORT) 1384 goto out; 1385 ipv6_stub->fib6_nh_release(fib6_nh); 1386 } else { 1387 nh->nh_flags = fib6_nh->fib_nh_flags; 1388 } 1389out: 1390 return err; 1391} 1392 1393static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg, 1394 struct netlink_ext_ack *extack) 1395{ 1396 struct nh_info *nhi; 1397 struct nexthop *nh; 1398 int err = 0; 1399 1400 nh = nexthop_alloc(); 1401 if (!nh) 1402 return ERR_PTR(-ENOMEM); 1403 1404 nhi = kzalloc(sizeof(*nhi), GFP_KERNEL); 1405 if (!nhi) { 1406 kfree(nh); 1407 return ERR_PTR(-ENOMEM); 1408 } 1409 1410 nh->nh_flags = cfg->nh_flags; 1411 nh->net = net; 1412 1413 nhi->nh_parent = nh; 1414 nhi->family = cfg->nh_family; 1415 nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK; 1416 1417 if (cfg->nh_fdb) 1418 nhi->fdb_nh = 1; 1419 1420 if (cfg->nh_blackhole) { 1421 nhi->reject_nh = 1; 1422 cfg->nh_ifindex = net->loopback_dev->ifindex; 1423 } 1424 1425 switch (cfg->nh_family) { 1426 case AF_INET: 1427 err = nh_create_ipv4(net, nh, nhi, cfg, extack); 1428 break; 1429 case AF_INET6: 1430 err = nh_create_ipv6(net, nh, nhi, cfg, extack); 1431 break; 1432 } 1433 1434 if (err) { 1435 kfree(nhi); 1436 kfree(nh); 1437 return ERR_PTR(err); 1438 } 1439 1440 /* add the entry to the device based hash */ 1441 if (!nhi->fdb_nh) 1442 nexthop_devhash_add(net, nhi); 1443 1444 rcu_assign_pointer(nh->nh_info, nhi); 1445 1446 return nh; 1447} 1448 1449/* called with rtnl lock held */ 1450static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg, 1451 struct netlink_ext_ack *extack) 1452{ 1453 struct nexthop *nh; 1454 int err; 1455 1456 if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) { 1457 NL_SET_ERR_MSG(extack, "Replace requires nexthop id"); 1458 return ERR_PTR(-EINVAL); 1459 } 1460 1461 if (!cfg->nh_id) { 1462 cfg->nh_id = nh_find_unused_id(net); 1463 if (!cfg->nh_id) { 1464 NL_SET_ERR_MSG(extack, "No unused id"); 1465 return ERR_PTR(-EINVAL); 1466 } 1467 } 1468 1469 if (cfg->nh_grp) 1470 nh = nexthop_create_group(net, cfg); 1471 else 1472 nh = nexthop_create(net, cfg, extack); 1473 1474 if (IS_ERR(nh)) 1475 return nh; 1476 1477 refcount_set(&nh->refcnt, 1); 1478 nh->id = cfg->nh_id; 1479 nh->protocol = cfg->nh_protocol; 1480 nh->net = net; 1481 1482 err = insert_nexthop(net, nh, cfg, extack); 1483 if (err) { 1484 __remove_nexthop(net, nh, NULL); 1485 nexthop_put(nh); 1486 nh = ERR_PTR(err); 1487 } 1488 1489 return nh; 1490} 1491 1492static int rtm_to_nh_config(struct net *net, struct sk_buff *skb, 1493 struct nlmsghdr *nlh, struct nh_config *cfg, 1494 struct netlink_ext_ack *extack) 1495{ 1496 struct nhmsg *nhm = nlmsg_data(nlh); 1497 struct nlattr *tb[NHA_MAX + 1]; 1498 int err; 1499 1500 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1501 extack); 1502 if (err < 0) 1503 return err; 1504 1505 err = -EINVAL; 1506 if (nhm->resvd || nhm->nh_scope) { 1507 NL_SET_ERR_MSG(extack, "Invalid values in ancillary header"); 1508 goto out; 1509 } 1510 if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) { 1511 NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header"); 1512 goto out; 1513 } 1514 1515 switch (nhm->nh_family) { 1516 case AF_INET: 1517 case AF_INET6: 1518 break; 1519 case AF_UNSPEC: 1520 if (tb[NHA_GROUP]) 1521 break; 1522 fallthrough; 1523 default: 1524 NL_SET_ERR_MSG(extack, "Invalid address family"); 1525 goto out; 1526 } 1527 1528 if (tb[NHA_GROUPS] || tb[NHA_MASTER]) { 1529 NL_SET_ERR_MSG(extack, "Invalid attributes in request"); 1530 goto out; 1531 } 1532 1533 memset(cfg, 0, sizeof(*cfg)); 1534 cfg->nlflags = nlh->nlmsg_flags; 1535 cfg->nlinfo.portid = NETLINK_CB(skb).portid; 1536 cfg->nlinfo.nlh = nlh; 1537 cfg->nlinfo.nl_net = net; 1538 1539 cfg->nh_family = nhm->nh_family; 1540 cfg->nh_protocol = nhm->nh_protocol; 1541 cfg->nh_flags = nhm->nh_flags; 1542 1543 if (tb[NHA_ID]) 1544 cfg->nh_id = nla_get_u32(tb[NHA_ID]); 1545 1546 if (tb[NHA_FDB]) { 1547 if (tb[NHA_OIF] || tb[NHA_BLACKHOLE] || 1548 tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE]) { 1549 NL_SET_ERR_MSG(extack, "Fdb attribute can not be used with encap, oif or blackhole"); 1550 goto out; 1551 } 1552 if (nhm->nh_flags) { 1553 NL_SET_ERR_MSG(extack, "Unsupported nexthop flags in ancillary header"); 1554 goto out; 1555 } 1556 cfg->nh_fdb = nla_get_flag(tb[NHA_FDB]); 1557 } 1558 1559 if (tb[NHA_GROUP]) { 1560 if (nhm->nh_family != AF_UNSPEC) { 1561 NL_SET_ERR_MSG(extack, "Invalid family for group"); 1562 goto out; 1563 } 1564 cfg->nh_grp = tb[NHA_GROUP]; 1565 1566 cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH; 1567 if (tb[NHA_GROUP_TYPE]) 1568 cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]); 1569 1570 if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) { 1571 NL_SET_ERR_MSG(extack, "Invalid group type"); 1572 goto out; 1573 } 1574 err = nh_check_attr_group(net, tb, extack); 1575 1576 /* no other attributes should be set */ 1577 goto out; 1578 } 1579 1580 if (tb[NHA_BLACKHOLE]) { 1581 if (tb[NHA_GATEWAY] || tb[NHA_OIF] || 1582 tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE] || tb[NHA_FDB]) { 1583 NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway, oif, encap or fdb"); 1584 goto out; 1585 } 1586 1587 cfg->nh_blackhole = 1; 1588 err = 0; 1589 goto out; 1590 } 1591 1592 if (!cfg->nh_fdb && !tb[NHA_OIF]) { 1593 NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole and non-fdb nexthops"); 1594 goto out; 1595 } 1596 1597 if (!cfg->nh_fdb && tb[NHA_OIF]) { 1598 cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]); 1599 if (cfg->nh_ifindex) 1600 cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex); 1601 1602 if (!cfg->dev) { 1603 NL_SET_ERR_MSG(extack, "Invalid device index"); 1604 goto out; 1605 } else if (!(cfg->dev->flags & IFF_UP)) { 1606 NL_SET_ERR_MSG(extack, "Nexthop device is not up"); 1607 err = -ENETDOWN; 1608 goto out; 1609 } else if (!netif_carrier_ok(cfg->dev)) { 1610 NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down"); 1611 err = -ENETDOWN; 1612 goto out; 1613 } 1614 } 1615 1616 err = -EINVAL; 1617 if (tb[NHA_GATEWAY]) { 1618 struct nlattr *gwa = tb[NHA_GATEWAY]; 1619 1620 switch (cfg->nh_family) { 1621 case AF_INET: 1622 if (nla_len(gwa) != sizeof(u32)) { 1623 NL_SET_ERR_MSG(extack, "Invalid gateway"); 1624 goto out; 1625 } 1626 cfg->gw.ipv4 = nla_get_be32(gwa); 1627 break; 1628 case AF_INET6: 1629 if (nla_len(gwa) != sizeof(struct in6_addr)) { 1630 NL_SET_ERR_MSG(extack, "Invalid gateway"); 1631 goto out; 1632 } 1633 cfg->gw.ipv6 = nla_get_in6_addr(gwa); 1634 break; 1635 default: 1636 NL_SET_ERR_MSG(extack, 1637 "Unknown address family for gateway"); 1638 goto out; 1639 } 1640 } else { 1641 /* device only nexthop (no gateway) */ 1642 if (cfg->nh_flags & RTNH_F_ONLINK) { 1643 NL_SET_ERR_MSG(extack, 1644 "ONLINK flag can not be set for nexthop without a gateway"); 1645 goto out; 1646 } 1647 } 1648 1649 if (tb[NHA_ENCAP]) { 1650 cfg->nh_encap = tb[NHA_ENCAP]; 1651 1652 if (!tb[NHA_ENCAP_TYPE]) { 1653 NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing"); 1654 goto out; 1655 } 1656 1657 cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]); 1658 err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack); 1659 if (err < 0) 1660 goto out; 1661 1662 } else if (tb[NHA_ENCAP_TYPE]) { 1663 NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing"); 1664 goto out; 1665 } 1666 1667 1668 err = 0; 1669out: 1670 return err; 1671} 1672 1673/* rtnl */ 1674static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh, 1675 struct netlink_ext_ack *extack) 1676{ 1677 struct net *net = sock_net(skb->sk); 1678 struct nh_config cfg; 1679 struct nexthop *nh; 1680 int err; 1681 1682 err = rtm_to_nh_config(net, skb, nlh, &cfg, extack); 1683 if (!err) { 1684 nh = nexthop_add(net, &cfg, extack); 1685 if (IS_ERR(nh)) 1686 err = PTR_ERR(nh); 1687 } 1688 1689 return err; 1690} 1691 1692static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id, 1693 struct netlink_ext_ack *extack) 1694{ 1695 struct nhmsg *nhm = nlmsg_data(nlh); 1696 struct nlattr *tb[NHA_MAX + 1]; 1697 int err, i; 1698 1699 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1700 extack); 1701 if (err < 0) 1702 return err; 1703 1704 err = -EINVAL; 1705 for (i = 0; i < __NHA_MAX; ++i) { 1706 if (!tb[i]) 1707 continue; 1708 1709 switch (i) { 1710 case NHA_ID: 1711 break; 1712 default: 1713 NL_SET_ERR_MSG_ATTR(extack, tb[i], 1714 "Unexpected attribute in request"); 1715 goto out; 1716 } 1717 } 1718 if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) { 1719 NL_SET_ERR_MSG(extack, "Invalid values in header"); 1720 goto out; 1721 } 1722 1723 if (!tb[NHA_ID]) { 1724 NL_SET_ERR_MSG(extack, "Nexthop id is missing"); 1725 goto out; 1726 } 1727 1728 *id = nla_get_u32(tb[NHA_ID]); 1729 if (!(*id)) 1730 NL_SET_ERR_MSG(extack, "Invalid nexthop id"); 1731 else 1732 err = 0; 1733out: 1734 return err; 1735} 1736 1737/* rtnl */ 1738static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh, 1739 struct netlink_ext_ack *extack) 1740{ 1741 struct net *net = sock_net(skb->sk); 1742 struct nl_info nlinfo = { 1743 .nlh = nlh, 1744 .nl_net = net, 1745 .portid = NETLINK_CB(skb).portid, 1746 }; 1747 struct nexthop *nh; 1748 int err; 1749 u32 id; 1750 1751 err = nh_valid_get_del_req(nlh, &id, extack); 1752 if (err) 1753 return err; 1754 1755 nh = nexthop_find_by_id(net, id); 1756 if (!nh) 1757 return -ENOENT; 1758 1759 remove_nexthop(net, nh, &nlinfo); 1760 1761 return 0; 1762} 1763 1764/* rtnl */ 1765static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh, 1766 struct netlink_ext_ack *extack) 1767{ 1768 struct net *net = sock_net(in_skb->sk); 1769 struct sk_buff *skb = NULL; 1770 struct nexthop *nh; 1771 int err; 1772 u32 id; 1773 1774 err = nh_valid_get_del_req(nlh, &id, extack); 1775 if (err) 1776 return err; 1777 1778 err = -ENOBUFS; 1779 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 1780 if (!skb) 1781 goto out; 1782 1783 err = -ENOENT; 1784 nh = nexthop_find_by_id(net, id); 1785 if (!nh) 1786 goto errout_free; 1787 1788 err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid, 1789 nlh->nlmsg_seq, 0); 1790 if (err < 0) { 1791 WARN_ON(err == -EMSGSIZE); 1792 goto errout_free; 1793 } 1794 1795 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 1796out: 1797 return err; 1798errout_free: 1799 kfree_skb(skb); 1800 goto out; 1801} 1802 1803static bool nh_dump_filtered(struct nexthop *nh, int dev_idx, int master_idx, 1804 bool group_filter, u8 family) 1805{ 1806 const struct net_device *dev; 1807 const struct nh_info *nhi; 1808 1809 if (group_filter && !nh->is_group) 1810 return true; 1811 1812 if (!dev_idx && !master_idx && !family) 1813 return false; 1814 1815 if (nh->is_group) 1816 return true; 1817 1818 nhi = rtnl_dereference(nh->nh_info); 1819 if (family && nhi->family != family) 1820 return true; 1821 1822 dev = nhi->fib_nhc.nhc_dev; 1823 if (dev_idx && (!dev || dev->ifindex != dev_idx)) 1824 return true; 1825 1826 if (master_idx) { 1827 struct net_device *master; 1828 1829 if (!dev) 1830 return true; 1831 1832 master = netdev_master_upper_dev_get((struct net_device *)dev); 1833 if (!master || master->ifindex != master_idx) 1834 return true; 1835 } 1836 1837 return false; 1838} 1839 1840static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx, 1841 int *master_idx, bool *group_filter, 1842 bool *fdb_filter, struct netlink_callback *cb) 1843{ 1844 struct netlink_ext_ack *extack = cb->extack; 1845 struct nlattr *tb[NHA_MAX + 1]; 1846 struct nhmsg *nhm; 1847 int err, i; 1848 u32 idx; 1849 1850 err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy, 1851 NULL); 1852 if (err < 0) 1853 return err; 1854 1855 for (i = 0; i <= NHA_MAX; ++i) { 1856 if (!tb[i]) 1857 continue; 1858 1859 switch (i) { 1860 case NHA_OIF: 1861 idx = nla_get_u32(tb[i]); 1862 if (idx > INT_MAX) { 1863 NL_SET_ERR_MSG(extack, "Invalid device index"); 1864 return -EINVAL; 1865 } 1866 *dev_idx = idx; 1867 break; 1868 case NHA_MASTER: 1869 idx = nla_get_u32(tb[i]); 1870 if (idx > INT_MAX) { 1871 NL_SET_ERR_MSG(extack, "Invalid master device index"); 1872 return -EINVAL; 1873 } 1874 *master_idx = idx; 1875 break; 1876 case NHA_GROUPS: 1877 *group_filter = true; 1878 break; 1879 case NHA_FDB: 1880 *fdb_filter = true; 1881 break; 1882 default: 1883 NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request"); 1884 return -EINVAL; 1885 } 1886 } 1887 1888 nhm = nlmsg_data(nlh); 1889 if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) { 1890 NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request"); 1891 return -EINVAL; 1892 } 1893 1894 return 0; 1895} 1896 1897/* rtnl */ 1898static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb) 1899{ 1900 bool group_filter = false, fdb_filter = false; 1901 struct nhmsg *nhm = nlmsg_data(cb->nlh); 1902 int dev_filter_idx = 0, master_idx = 0; 1903 struct net *net = sock_net(skb->sk); 1904 struct rb_root *root = &net->nexthop.rb_root; 1905 struct rb_node *node; 1906 int idx = 0, s_idx; 1907 int err; 1908 1909 err = nh_valid_dump_req(cb->nlh, &dev_filter_idx, &master_idx, 1910 &group_filter, &fdb_filter, cb); 1911 if (err < 0) 1912 return err; 1913 1914 s_idx = cb->args[0]; 1915 for (node = rb_first(root); node; node = rb_next(node)) { 1916 struct nexthop *nh; 1917 1918 if (idx < s_idx) 1919 goto cont; 1920 1921 nh = rb_entry(node, struct nexthop, rb_node); 1922 if (nh_dump_filtered(nh, dev_filter_idx, master_idx, 1923 group_filter, nhm->nh_family)) 1924 goto cont; 1925 1926 err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, 1927 NETLINK_CB(cb->skb).portid, 1928 cb->nlh->nlmsg_seq, NLM_F_MULTI); 1929 if (err < 0) { 1930 if (likely(skb->len)) 1931 goto out; 1932 1933 goto out_err; 1934 } 1935cont: 1936 idx++; 1937 } 1938 1939out: 1940 err = skb->len; 1941out_err: 1942 cb->args[0] = idx; 1943 cb->seq = net->nexthop.seq; 1944 nl_dump_check_consistent(cb, nlmsg_hdr(skb)); 1945 1946 return err; 1947} 1948 1949static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu) 1950{ 1951 unsigned int hash = nh_dev_hashfn(dev->ifindex); 1952 struct net *net = dev_net(dev); 1953 struct hlist_head *head = &net->nexthop.devhash[hash]; 1954 struct hlist_node *n; 1955 struct nh_info *nhi; 1956 1957 hlist_for_each_entry_safe(nhi, n, head, dev_hash) { 1958 if (nhi->fib_nhc.nhc_dev == dev) { 1959 if (nhi->family == AF_INET) 1960 fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu, 1961 orig_mtu); 1962 } 1963 } 1964} 1965 1966/* rtnl */ 1967static int nh_netdev_event(struct notifier_block *this, 1968 unsigned long event, void *ptr) 1969{ 1970 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1971 struct netdev_notifier_info_ext *info_ext; 1972 1973 switch (event) { 1974 case NETDEV_DOWN: 1975 case NETDEV_UNREGISTER: 1976 nexthop_flush_dev(dev, event); 1977 break; 1978 case NETDEV_CHANGE: 1979 if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP))) 1980 nexthop_flush_dev(dev, event); 1981 break; 1982 case NETDEV_CHANGEMTU: 1983 info_ext = ptr; 1984 nexthop_sync_mtu(dev, info_ext->ext.mtu); 1985 rt_cache_flush(dev_net(dev)); 1986 break; 1987 } 1988 return NOTIFY_DONE; 1989} 1990 1991static struct notifier_block nh_netdev_notifier = { 1992 .notifier_call = nh_netdev_event, 1993}; 1994 1995int register_nexthop_notifier(struct net *net, struct notifier_block *nb) 1996{ 1997 return blocking_notifier_chain_register(&net->nexthop.notifier_chain, 1998 nb); 1999} 2000EXPORT_SYMBOL(register_nexthop_notifier); 2001 2002int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb) 2003{ 2004 return blocking_notifier_chain_unregister(&net->nexthop.notifier_chain, 2005 nb); 2006} 2007EXPORT_SYMBOL(unregister_nexthop_notifier); 2008 2009static void __net_exit nexthop_net_exit(struct net *net) 2010{ 2011 rtnl_lock(); 2012 flush_all_nexthops(net); 2013 rtnl_unlock(); 2014 kfree(net->nexthop.devhash); 2015} 2016 2017static int __net_init nexthop_net_init(struct net *net) 2018{ 2019 size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE; 2020 2021 net->nexthop.rb_root = RB_ROOT; 2022 net->nexthop.devhash = kzalloc(sz, GFP_KERNEL); 2023 if (!net->nexthop.devhash) 2024 return -ENOMEM; 2025 BLOCKING_INIT_NOTIFIER_HEAD(&net->nexthop.notifier_chain); 2026 2027 return 0; 2028} 2029 2030static struct pernet_operations nexthop_net_ops = { 2031 .init = nexthop_net_init, 2032 .exit = nexthop_net_exit, 2033}; 2034 2035static int __init nexthop_init(void) 2036{ 2037 register_pernet_subsys(&nexthop_net_ops); 2038 2039 register_netdevice_notifier(&nh_netdev_notifier); 2040 2041 rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 2042 rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0); 2043 rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop, 2044 rtm_dump_nexthop, 0); 2045 2046 rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 2047 rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0); 2048 2049 rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0); 2050 rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0); 2051 2052 return 0; 2053} 2054subsys_initcall(nexthop_init); 2055