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