net/ipv4/nexthop.c

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