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 <[email protected]>
   6  */
   7
   8 #include <linux/nexthop.h>
   9 #include <linux/rtnetlink.h>
  10 #include <linux/slab.h>
  11 #include <linux/vmalloc.h>
  12 #include <net/arp.h>
  13 #include <net/ipv6_stubs.h>
  14 #include <net/lwtunnel.h>
  15 #include <net/ndisc.h>
  16 #include <net/nexthop.h>
  17 #include <net/route.h>
  18 #include <net/sock.h>
  19
  20 #define NH_RES_DEFAULT_IDLE_TIMER       (120 * HZ)
  21 #define NH_RES_DEFAULT_UNBALANCED_TIMER 0       /* No forced rebalancing. */
  22
  23 static void remove_nexthop(struct net *net, struct nexthop *nh,
  24                            struct nl_info *nlinfo);
  25
  26 #define NH_DEV_HASHBITS  8
  27 #define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS)
  28
  29 static const struct nla_policy rtm_nh_policy_new[] = {
  30         [NHA_ID]                = { .type = NLA_U32 },
  31         [NHA_GROUP]             = { .type = NLA_BINARY },
  32         [NHA_GROUP_TYPE]        = { .type = NLA_U16 },
  33         [NHA_BLACKHOLE]         = { .type = NLA_FLAG },
  34         [NHA_OIF]               = { .type = NLA_U32 },
  35         [NHA_GATEWAY]           = { .type = NLA_BINARY },
  36         [NHA_ENCAP_TYPE]        = { .type = NLA_U16 },
  37         [NHA_ENCAP]             = { .type = NLA_NESTED },
  38         [NHA_FDB]               = { .type = NLA_FLAG },
  39         [NHA_RES_GROUP]         = { .type = NLA_NESTED },
  40 };
  41
  42 static const struct nla_policy rtm_nh_policy_get[] = {
  43         [NHA_ID]                = { .type = NLA_U32 },
  44 };
  45
  46 static const struct nla_policy rtm_nh_policy_dump[] = {
  47         [NHA_OIF]               = { .type = NLA_U32 },
  48         [NHA_GROUPS]            = { .type = NLA_FLAG },
  49         [NHA_MASTER]            = { .type = NLA_U32 },
  50         [NHA_FDB]               = { .type = NLA_FLAG },
  51 };
  52
  53 static const struct nla_policy rtm_nh_res_policy_new[] = {
  54         [NHA_RES_GROUP_BUCKETS]                 = { .type = NLA_U16 },
  55         [NHA_RES_GROUP_IDLE_TIMER]              = { .type = NLA_U32 },
  56         [NHA_RES_GROUP_UNBALANCED_TIMER]        = { .type = NLA_U32 },
  57 };
  58
  59 static const struct nla_policy rtm_nh_policy_dump_bucket[] = {
  60         [NHA_ID]                = { .type = NLA_U32 },
  61         [NHA_OIF]               = { .type = NLA_U32 },
  62         [NHA_MASTER]            = { .type = NLA_U32 },
  63         [NHA_RES_BUCKET]        = { .type = NLA_NESTED },
  64 };
  65
  66 static const struct nla_policy rtm_nh_res_bucket_policy_dump[] = {
  67         [NHA_RES_BUCKET_NH_ID]  = { .type = NLA_U32 },
  68 };
  69
  70 static const struct nla_policy rtm_nh_policy_get_bucket[] = {
  71         [NHA_ID]                = { .type = NLA_U32 },
  72         [NHA_RES_BUCKET]        = { .type = NLA_NESTED },
  73 };
  74
  75 static const struct nla_policy rtm_nh_res_bucket_policy_get[] = {
  76         [NHA_RES_BUCKET_INDEX]  = { .type = NLA_U16 },
  77 };
  78
  79 static bool nexthop_notifiers_is_empty(struct net *net)
  80 {
  81         return !net->nexthop.notifier_chain.head;
  82 }
  83
  84 static void
  85 __nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
  86                                const struct nh_info *nhi)
  87 {
  88         nh_info->dev = nhi->fib_nhc.nhc_dev;
  89         nh_info->gw_family = nhi->fib_nhc.nhc_gw_family;
  90         if (nh_info->gw_family == AF_INET)
  91                 nh_info->ipv4 = nhi->fib_nhc.nhc_gw.ipv4;
  92         else if (nh_info->gw_family == AF_INET6)
  93                 nh_info->ipv6 = nhi->fib_nhc.nhc_gw.ipv6;
  94
  95         nh_info->is_reject = nhi->reject_nh;
  96         nh_info->is_fdb = nhi->fdb_nh;
  97         nh_info->has_encap = !!nhi->fib_nhc.nhc_lwtstate;
  98 }
  99
 100 static int nh_notifier_single_info_init(struct nh_notifier_info *info,
 101                                         const struct nexthop *nh)
 102 {
 103         struct nh_info *nhi = rtnl_dereference(nh->nh_info);
 104
 105         info->type = NH_NOTIFIER_INFO_TYPE_SINGLE;
 106         info->nh = kzalloc(sizeof(*info->nh), GFP_KERNEL);
 107         if (!info->nh)
 108                 return -ENOMEM;
 109
 110         __nh_notifier_single_info_init(info->nh, nhi);
 111
 112         return 0;
 113 }
 114
 115 static void nh_notifier_single_info_fini(struct nh_notifier_info *info)
 116 {
 117         kfree(info->nh);
 118 }
 119
 120 static int nh_notifier_mpath_info_init(struct nh_notifier_info *info,
 121                                        struct nh_group *nhg)
 122 {
 123         u16 num_nh = nhg->num_nh;
 124         int i;
 125
 126         info->type = NH_NOTIFIER_INFO_TYPE_GRP;
 127         info->nh_grp = kzalloc(struct_size(info->nh_grp, nh_entries, num_nh),
 128                                GFP_KERNEL);
 129         if (!info->nh_grp)
 130                 return -ENOMEM;
 131
 132         info->nh_grp->num_nh = num_nh;
 133         info->nh_grp->is_fdb = nhg->fdb_nh;
 134
 135         for (i = 0; i < num_nh; i++) {
 136                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
 137                 struct nh_info *nhi;
 138
 139                 nhi = rtnl_dereference(nhge->nh->nh_info);
 140                 info->nh_grp->nh_entries[i].id = nhge->nh->id;
 141                 info->nh_grp->nh_entries[i].weight = nhge->weight;
 142                 __nh_notifier_single_info_init(&info->nh_grp->nh_entries[i].nh,
 143                                                nhi);
 144         }
 145
 146         return 0;
 147 }
 148
 149 static int nh_notifier_res_table_info_init(struct nh_notifier_info *info,
 150                                            struct nh_group *nhg)
 151 {
 152         struct nh_res_table *res_table = rtnl_dereference(nhg->res_table);
 153         u16 num_nh_buckets = res_table->num_nh_buckets;
 154         unsigned long size;
 155         u16 i;
 156
 157         info->type = NH_NOTIFIER_INFO_TYPE_RES_TABLE;
 158         size = struct_size(info->nh_res_table, nhs, num_nh_buckets);
 159         info->nh_res_table = __vmalloc(size, GFP_KERNEL | __GFP_ZERO |
 160                                        __GFP_NOWARN);
 161         if (!info->nh_res_table)
 162                 return -ENOMEM;
 163
 164         info->nh_res_table->num_nh_buckets = num_nh_buckets;
 165
 166         for (i = 0; i < num_nh_buckets; i++) {
 167                 struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
 168                 struct nh_grp_entry *nhge;
 169                 struct nh_info *nhi;
 170
 171                 nhge = rtnl_dereference(bucket->nh_entry);
 172                 nhi = rtnl_dereference(nhge->nh->nh_info);
 173                 __nh_notifier_single_info_init(&info->nh_res_table->nhs[i],
 174                                                nhi);
 175         }
 176
 177         return 0;
 178 }
 179
 180 static int nh_notifier_grp_info_init(struct nh_notifier_info *info,
 181                                      const struct nexthop *nh)
 182 {
 183         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 184
 185         if (nhg->hash_threshold)
 186                 return nh_notifier_mpath_info_init(info, nhg);
 187         else if (nhg->resilient)
 188                 return nh_notifier_res_table_info_init(info, nhg);
 189         return -EINVAL;
 190 }
 191
 192 static void nh_notifier_grp_info_fini(struct nh_notifier_info *info,
 193                                       const struct nexthop *nh)
 194 {
 195         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 196
 197         if (nhg->hash_threshold)
 198                 kfree(info->nh_grp);
 199         else if (nhg->resilient)
 200                 vfree(info->nh_res_table);
 201 }
 202
 203 static int nh_notifier_info_init(struct nh_notifier_info *info,
 204                                  const struct nexthop *nh)
 205 {
 206         info->id = nh->id;
 207
 208         if (nh->is_group)
 209                 return nh_notifier_grp_info_init(info, nh);
 210         else
 211                 return nh_notifier_single_info_init(info, nh);
 212 }
 213
 214 static void nh_notifier_info_fini(struct nh_notifier_info *info,
 215                                   const struct nexthop *nh)
 216 {
 217         if (nh->is_group)
 218                 nh_notifier_grp_info_fini(info, nh);
 219         else
 220                 nh_notifier_single_info_fini(info);
 221 }
 222
 223 static int call_nexthop_notifiers(struct net *net,
 224                                   enum nexthop_event_type event_type,
 225                                   struct nexthop *nh,
 226                                   struct netlink_ext_ack *extack)
 227 {
 228         struct nh_notifier_info info = {
 229                 .net = net,
 230                 .extack = extack,
 231         };
 232         int err;
 233
 234         ASSERT_RTNL();
 235
 236         if (nexthop_notifiers_is_empty(net))
 237                 return 0;
 238
 239         err = nh_notifier_info_init(&info, nh);
 240         if (err) {
 241                 NL_SET_ERR_MSG(extack, "Failed to initialize nexthop notifier info");
 242                 return err;
 243         }
 244
 245         err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
 246                                            event_type, &info);
 247         nh_notifier_info_fini(&info, nh);
 248
 249         return notifier_to_errno(err);
 250 }
 251
 252 static int
 253 nh_notifier_res_bucket_idle_timer_get(const struct nh_notifier_info *info,
 254                                       bool force, unsigned int *p_idle_timer_ms)
 255 {
 256         struct nh_res_table *res_table;
 257         struct nh_group *nhg;
 258         struct nexthop *nh;
 259         int err = 0;
 260
 261         /* When 'force' is false, nexthop bucket replacement is performed
 262          * because the bucket was deemed to be idle. In this case, capable
 263          * listeners can choose to perform an atomic replacement: The bucket is
 264          * only replaced if it is inactive. However, if the idle timer interval
 265          * is smaller than the interval in which a listener is querying
 266          * buckets' activity from the device, then atomic replacement should
 267          * not be tried. Pass the idle timer value to listeners, so that they
 268          * could determine which type of replacement to perform.
 269          */
 270         if (force) {
 271                 *p_idle_timer_ms = 0;
 272                 return 0;
 273         }
 274
 275         rcu_read_lock();
 276
 277         nh = nexthop_find_by_id(info->net, info->id);
 278         if (!nh) {
 279                 err = -EINVAL;
 280                 goto out;
 281         }
 282
 283         nhg = rcu_dereference(nh->nh_grp);
 284         res_table = rcu_dereference(nhg->res_table);
 285         *p_idle_timer_ms = jiffies_to_msecs(res_table->idle_timer);
 286
 287 out:
 288         rcu_read_unlock();
 289
 290         return err;
 291 }
 292
 293 static int nh_notifier_res_bucket_info_init(struct nh_notifier_info *info,
 294                                             u16 bucket_index, bool force,
 295                                             struct nh_info *oldi,
 296                                             struct nh_info *newi)
 297 {
 298         unsigned int idle_timer_ms;
 299         int err;
 300
 301         err = nh_notifier_res_bucket_idle_timer_get(info, force,
 302                                                     &idle_timer_ms);
 303         if (err)
 304                 return err;
 305
 306         info->type = NH_NOTIFIER_INFO_TYPE_RES_BUCKET;
 307         info->nh_res_bucket = kzalloc(sizeof(*info->nh_res_bucket),
 308                                       GFP_KERNEL);
 309         if (!info->nh_res_bucket)
 310                 return -ENOMEM;
 311
 312         info->nh_res_bucket->bucket_index = bucket_index;
 313         info->nh_res_bucket->idle_timer_ms = idle_timer_ms;
 314         info->nh_res_bucket->force = force;
 315         __nh_notifier_single_info_init(&info->nh_res_bucket->old_nh, oldi);
 316         __nh_notifier_single_info_init(&info->nh_res_bucket->new_nh, newi);
 317         return 0;
 318 }
 319
 320 static void nh_notifier_res_bucket_info_fini(struct nh_notifier_info *info)
 321 {
 322         kfree(info->nh_res_bucket);
 323 }
 324
 325 static int __call_nexthop_res_bucket_notifiers(struct net *net, u32 nhg_id,
 326                                                u16 bucket_index, bool force,
 327                                                struct nh_info *oldi,
 328                                                struct nh_info *newi,
 329                                                struct netlink_ext_ack *extack)
 330 {
 331         struct nh_notifier_info info = {
 332                 .net = net,
 333                 .extack = extack,
 334                 .id = nhg_id,
 335         };
 336         int err;
 337
 338         if (nexthop_notifiers_is_empty(net))
 339                 return 0;
 340
 341         err = nh_notifier_res_bucket_info_init(&info, bucket_index, force,
 342                                                oldi, newi);
 343         if (err)
 344                 return err;
 345
 346         err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
 347                                            NEXTHOP_EVENT_BUCKET_REPLACE, &info);
 348         nh_notifier_res_bucket_info_fini(&info);
 349
 350         return notifier_to_errno(err);
 351 }
 352
 353 /* There are three users of RES_TABLE, and NHs etc. referenced from there:
 354  *
 355  * 1) a collection of callbacks for NH maintenance. This operates under
 356  *    RTNL,
 357  * 2) the delayed work that gradually balances the resilient table,
 358  * 3) and nexthop_select_path(), operating under RCU.
 359  *
 360  * Both the delayed work and the RTNL block are writers, and need to
 361  * maintain mutual exclusion. Since there are only two and well-known
 362  * writers for each table, the RTNL code can make sure it has exclusive
 363  * access thus:
 364  *
 365  * - Have the DW operate without locking;
 366  * - synchronously cancel the DW;
 367  * - do the writing;
 368  * - if the write was not actually a delete, call upkeep, which schedules
 369  *   DW again if necessary.
 370  *
 371  * The functions that are always called from the RTNL context use
 372  * rtnl_dereference(). The functions that can also be called from the DW do
 373  * a raw dereference and rely on the above mutual exclusion scheme.
 374  */
 375 #define nh_res_dereference(p) (rcu_dereference_raw(p))
 376
 377 static int call_nexthop_res_bucket_notifiers(struct net *net, u32 nhg_id,
 378                                              u16 bucket_index, bool force,
 379                                              struct nexthop *old_nh,
 380                                              struct nexthop *new_nh,
 381                                              struct netlink_ext_ack *extack)
 382 {
 383         struct nh_info *oldi = nh_res_dereference(old_nh->nh_info);
 384         struct nh_info *newi = nh_res_dereference(new_nh->nh_info);
 385
 386         return __call_nexthop_res_bucket_notifiers(net, nhg_id, bucket_index,
 387                                                    force, oldi, newi, extack);
 388 }
 389
 390 static int call_nexthop_res_table_notifiers(struct net *net, struct nexthop *nh,
 391                                             struct netlink_ext_ack *extack)
 392 {
 393         struct nh_notifier_info info = {
 394                 .net = net,
 395                 .extack = extack,
 396         };
 397         struct nh_group *nhg;
 398         int err;
 399
 400         ASSERT_RTNL();
 401
 402         if (nexthop_notifiers_is_empty(net))
 403                 return 0;
 404
 405         /* At this point, the nexthop buckets are still not populated. Only
 406          * emit a notification with the logical nexthops, so that a listener
 407          * could potentially veto it in case of unsupported configuration.
 408          */
 409         nhg = rtnl_dereference(nh->nh_grp);
 410         err = nh_notifier_mpath_info_init(&info, nhg);
 411         if (err) {
 412                 NL_SET_ERR_MSG(extack, "Failed to initialize nexthop notifier info");
 413                 return err;
 414         }
 415
 416         err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
 417                                            NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
 418                                            &info);
 419         kfree(info.nh_grp);
 420
 421         return notifier_to_errno(err);
 422 }
 423
 424 static int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
 425                                  enum nexthop_event_type event_type,
 426                                  struct nexthop *nh,
 427                                  struct netlink_ext_ack *extack)
 428 {
 429         struct nh_notifier_info info = {
 430                 .net = net,
 431                 .extack = extack,
 432         };
 433         int err;
 434
 435         err = nh_notifier_info_init(&info, nh);
 436         if (err)
 437                 return err;
 438
 439         err = nb->notifier_call(nb, event_type, &info);
 440         nh_notifier_info_fini(&info, nh);
 441
 442         return notifier_to_errno(err);
 443 }
 444
 445 static unsigned int nh_dev_hashfn(unsigned int val)
 446 {
 447         unsigned int mask = NH_DEV_HASHSIZE - 1;
 448
 449         return (val ^
 450                 (val >> NH_DEV_HASHBITS) ^
 451                 (val >> (NH_DEV_HASHBITS * 2))) & mask;
 452 }
 453
 454 static void nexthop_devhash_add(struct net *net, struct nh_info *nhi)
 455 {
 456         struct net_device *dev = nhi->fib_nhc.nhc_dev;
 457         struct hlist_head *head;
 458         unsigned int hash;
 459
 460         WARN_ON(!dev);
 461
 462         hash = nh_dev_hashfn(dev->ifindex);
 463         head = &net->nexthop.devhash[hash];
 464         hlist_add_head(&nhi->dev_hash, head);
 465 }
 466
 467 static void nexthop_free_group(struct nexthop *nh)
 468 {
 469         struct nh_group *nhg;
 470         int i;
 471
 472         nhg = rcu_dereference_raw(nh->nh_grp);
 473         for (i = 0; i < nhg->num_nh; ++i) {
 474                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
 475
 476                 WARN_ON(!list_empty(&nhge->nh_list));
 477                 nexthop_put(nhge->nh);
 478         }
 479
 480         WARN_ON(nhg->spare == nhg);
 481
 482         if (nhg->resilient)
 483                 vfree(rcu_dereference_raw(nhg->res_table));
 484
 485         kfree(nhg->spare);
 486         kfree(nhg);
 487 }
 488
 489 static void nexthop_free_single(struct nexthop *nh)
 490 {
 491         struct nh_info *nhi;
 492
 493         nhi = rcu_dereference_raw(nh->nh_info);
 494         switch (nhi->family) {
 495         case AF_INET:
 496                 fib_nh_release(nh->net, &nhi->fib_nh);
 497                 break;
 498         case AF_INET6:
 499                 ipv6_stub->fib6_nh_release(&nhi->fib6_nh);
 500                 break;
 501         }
 502         kfree(nhi);
 503 }
 504
 505 void nexthop_free_rcu(struct rcu_head *head)
 506 {
 507         struct nexthop *nh = container_of(head, struct nexthop, rcu);
 508
 509         if (nh->is_group)
 510                 nexthop_free_group(nh);
 511         else
 512                 nexthop_free_single(nh);
 513
 514         kfree(nh);
 515 }
 516 EXPORT_SYMBOL_GPL(nexthop_free_rcu);
 517
 518 static struct nexthop *nexthop_alloc(void)
 519 {
 520         struct nexthop *nh;
 521
 522         nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
 523         if (nh) {
 524                 INIT_LIST_HEAD(&nh->fi_list);
 525                 INIT_LIST_HEAD(&nh->f6i_list);
 526                 INIT_LIST_HEAD(&nh->grp_list);
 527                 INIT_LIST_HEAD(&nh->fdb_list);
 528         }
 529         return nh;
 530 }
 531
 532 static struct nh_group *nexthop_grp_alloc(u16 num_nh)
 533 {
 534         struct nh_group *nhg;
 535
 536         nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL);
 537         if (nhg)
 538                 nhg->num_nh = num_nh;
 539
 540         return nhg;
 541 }
 542
 543 static void nh_res_table_upkeep_dw(struct work_struct *work);
 544
 545 static struct nh_res_table *
 546 nexthop_res_table_alloc(struct net *net, u32 nhg_id, struct nh_config *cfg)
 547 {
 548         const u16 num_nh_buckets = cfg->nh_grp_res_num_buckets;
 549         struct nh_res_table *res_table;
 550         unsigned long size;
 551
 552         size = struct_size(res_table, nh_buckets, num_nh_buckets);
 553         res_table = __vmalloc(size, GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
 554         if (!res_table)
 555                 return NULL;
 556
 557         res_table->net = net;
 558         res_table->nhg_id = nhg_id;
 559         INIT_DELAYED_WORK(&res_table->upkeep_dw, &nh_res_table_upkeep_dw);
 560         INIT_LIST_HEAD(&res_table->uw_nh_entries);
 561         res_table->idle_timer = cfg->nh_grp_res_idle_timer;
 562         res_table->unbalanced_timer = cfg->nh_grp_res_unbalanced_timer;
 563         res_table->num_nh_buckets = num_nh_buckets;
 564         return res_table;
 565 }
 566
 567 static void nh_base_seq_inc(struct net *net)
 568 {
 569         while (++net->nexthop.seq == 0)
 570                 ;
 571 }
 572
 573 /* no reference taken; rcu lock or rtnl must be held */
 574 struct nexthop *nexthop_find_by_id(struct net *net, u32 id)
 575 {
 576         struct rb_node **pp, *parent = NULL, *next;
 577
 578         pp = &net->nexthop.rb_root.rb_node;
 579         while (1) {
 580                 struct nexthop *nh;
 581
 582                 next = rcu_dereference_raw(*pp);
 583                 if (!next)
 584                         break;
 585                 parent = next;
 586
 587                 nh = rb_entry(parent, struct nexthop, rb_node);
 588                 if (id < nh->id)
 589                         pp = &next->rb_left;
 590                 else if (id > nh->id)
 591                         pp = &next->rb_right;
 592                 else
 593                         return nh;
 594         }
 595         return NULL;
 596 }
 597 EXPORT_SYMBOL_GPL(nexthop_find_by_id);
 598
 599 /* used for auto id allocation; called with rtnl held */
 600 static u32 nh_find_unused_id(struct net *net)
 601 {
 602         u32 id_start = net->nexthop.last_id_allocated;
 603
 604         while (1) {
 605                 net->nexthop.last_id_allocated++;
 606                 if (net->nexthop.last_id_allocated == id_start)
 607                         break;
 608
 609                 if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated))
 610                         return net->nexthop.last_id_allocated;
 611         }
 612         return 0;
 613 }
 614
 615 static void nh_res_time_set_deadline(unsigned long next_time,
 616                                      unsigned long *deadline)
 617 {
 618         if (time_before(next_time, *deadline))
 619                 *deadline = next_time;
 620 }
 621
 622 static clock_t nh_res_table_unbalanced_time(struct nh_res_table *res_table)
 623 {
 624         if (list_empty(&res_table->uw_nh_entries))
 625                 return 0;
 626         return jiffies_delta_to_clock_t(jiffies - res_table->unbalanced_since);
 627 }
 628
 629 static int nla_put_nh_group_res(struct sk_buff *skb, struct nh_group *nhg)
 630 {
 631         struct nh_res_table *res_table = rtnl_dereference(nhg->res_table);
 632         struct nlattr *nest;
 633
 634         nest = nla_nest_start(skb, NHA_RES_GROUP);
 635         if (!nest)
 636                 return -EMSGSIZE;
 637
 638         if (nla_put_u16(skb, NHA_RES_GROUP_BUCKETS,
 639                         res_table->num_nh_buckets) ||
 640             nla_put_u32(skb, NHA_RES_GROUP_IDLE_TIMER,
 641                         jiffies_to_clock_t(res_table->idle_timer)) ||
 642             nla_put_u32(skb, NHA_RES_GROUP_UNBALANCED_TIMER,
 643                         jiffies_to_clock_t(res_table->unbalanced_timer)) ||
 644             nla_put_u64_64bit(skb, NHA_RES_GROUP_UNBALANCED_TIME,
 645                               nh_res_table_unbalanced_time(res_table),
 646                               NHA_RES_GROUP_PAD))
 647                 goto nla_put_failure;
 648
 649         nla_nest_end(skb, nest);
 650         return 0;
 651
 652 nla_put_failure:
 653         nla_nest_cancel(skb, nest);
 654         return -EMSGSIZE;
 655 }
 656
 657 static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
 658 {
 659         struct nexthop_grp *p;
 660         size_t len = nhg->num_nh * sizeof(*p);
 661         struct nlattr *nla;
 662         u16 group_type = 0;
 663         int i;
 664
 665         if (nhg->hash_threshold)
 666                 group_type = NEXTHOP_GRP_TYPE_MPATH;
 667         else if (nhg->resilient)
 668                 group_type = NEXTHOP_GRP_TYPE_RES;
 669
 670         if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type))
 671                 goto nla_put_failure;
 672
 673         nla = nla_reserve(skb, NHA_GROUP, len);
 674         if (!nla)
 675                 goto nla_put_failure;
 676
 677         p = nla_data(nla);
 678         for (i = 0; i < nhg->num_nh; ++i) {
 679                 p->id = nhg->nh_entries[i].nh->id;
 680                 p->weight = nhg->nh_entries[i].weight - 1;
 681                 p += 1;
 682         }
 683
 684         if (nhg->resilient && nla_put_nh_group_res(skb, nhg))
 685                 goto nla_put_failure;
 686
 687         return 0;
 688
 689 nla_put_failure:
 690         return -EMSGSIZE;
 691 }
 692
 693 static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
 694                         int event, u32 portid, u32 seq, unsigned int nlflags)
 695 {
 696         struct fib6_nh *fib6_nh;
 697         struct fib_nh *fib_nh;
 698         struct nlmsghdr *nlh;
 699         struct nh_info *nhi;
 700         struct nhmsg *nhm;
 701
 702         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
 703         if (!nlh)
 704                 return -EMSGSIZE;
 705
 706         nhm = nlmsg_data(nlh);
 707         nhm->nh_family = AF_UNSPEC;
 708         nhm->nh_flags = nh->nh_flags;
 709         nhm->nh_protocol = nh->protocol;
 710         nhm->nh_scope = 0;
 711         nhm->resvd = 0;
 712
 713         if (nla_put_u32(skb, NHA_ID, nh->id))
 714                 goto nla_put_failure;
 715
 716         if (nh->is_group) {
 717                 struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 718
 719                 if (nhg->fdb_nh && nla_put_flag(skb, NHA_FDB))
 720                         goto nla_put_failure;
 721                 if (nla_put_nh_group(skb, nhg))
 722                         goto nla_put_failure;
 723                 goto out;
 724         }
 725
 726         nhi = rtnl_dereference(nh->nh_info);
 727         nhm->nh_family = nhi->family;
 728         if (nhi->reject_nh) {
 729                 if (nla_put_flag(skb, NHA_BLACKHOLE))
 730                         goto nla_put_failure;
 731                 goto out;
 732         } else if (nhi->fdb_nh) {
 733                 if (nla_put_flag(skb, NHA_FDB))
 734                         goto nla_put_failure;
 735         } else {
 736                 const struct net_device *dev;
 737
 738                 dev = nhi->fib_nhc.nhc_dev;
 739                 if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex))
 740                         goto nla_put_failure;
 741         }
 742
 743         nhm->nh_scope = nhi->fib_nhc.nhc_scope;
 744         switch (nhi->family) {
 745         case AF_INET:
 746                 fib_nh = &nhi->fib_nh;
 747                 if (fib_nh->fib_nh_gw_family &&
 748                     nla_put_be32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4))
 749                         goto nla_put_failure;
 750                 break;
 751
 752         case AF_INET6:
 753                 fib6_nh = &nhi->fib6_nh;
 754                 if (fib6_nh->fib_nh_gw_family &&
 755                     nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6))
 756                         goto nla_put_failure;
 757                 break;
 758         }
 759
 760         if (nhi->fib_nhc.nhc_lwtstate &&
 761             lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate,
 762                                 NHA_ENCAP, NHA_ENCAP_TYPE) < 0)
 763                 goto nla_put_failure;
 764
 765 out:
 766         nlmsg_end(skb, nlh);
 767         return 0;
 768
 769 nla_put_failure:
 770         nlmsg_cancel(skb, nlh);
 771         return -EMSGSIZE;
 772 }
 773
 774 static size_t nh_nlmsg_size_grp_res(struct nh_group *nhg)
 775 {
 776         return nla_total_size(0) +      /* NHA_RES_GROUP */
 777                 nla_total_size(2) +     /* NHA_RES_GROUP_BUCKETS */
 778                 nla_total_size(4) +     /* NHA_RES_GROUP_IDLE_TIMER */
 779                 nla_total_size(4) +     /* NHA_RES_GROUP_UNBALANCED_TIMER */
 780                 nla_total_size_64bit(8);/* NHA_RES_GROUP_UNBALANCED_TIME */
 781 }
 782
 783 static size_t nh_nlmsg_size_grp(struct nexthop *nh)
 784 {
 785         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 786         size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh;
 787         size_t tot = nla_total_size(sz) +
 788                 nla_total_size(2); /* NHA_GROUP_TYPE */
 789
 790         if (nhg->resilient)
 791                 tot += nh_nlmsg_size_grp_res(nhg);
 792
 793         return tot;
 794 }
 795
 796 static size_t nh_nlmsg_size_single(struct nexthop *nh)
 797 {
 798         struct nh_info *nhi = rtnl_dereference(nh->nh_info);
 799         size_t sz;
 800
 801         /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE
 802          * are mutually exclusive
 803          */
 804         sz = nla_total_size(4);  /* NHA_OIF */
 805
 806         switch (nhi->family) {
 807         case AF_INET:
 808                 if (nhi->fib_nh.fib_nh_gw_family)
 809                         sz += nla_total_size(4);  /* NHA_GATEWAY */
 810                 break;
 811
 812         case AF_INET6:
 813                 /* NHA_GATEWAY */
 814                 if (nhi->fib6_nh.fib_nh_gw_family)
 815                         sz += nla_total_size(sizeof(const struct in6_addr));
 816                 break;
 817         }
 818
 819         if (nhi->fib_nhc.nhc_lwtstate) {
 820                 sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate);
 821                 sz += nla_total_size(2);  /* NHA_ENCAP_TYPE */
 822         }
 823
 824         return sz;
 825 }
 826
 827 static size_t nh_nlmsg_size(struct nexthop *nh)
 828 {
 829         size_t sz = NLMSG_ALIGN(sizeof(struct nhmsg));
 830
 831         sz += nla_total_size(4); /* NHA_ID */
 832
 833         if (nh->is_group)
 834                 sz += nh_nlmsg_size_grp(nh);
 835         else
 836                 sz += nh_nlmsg_size_single(nh);
 837
 838         return sz;
 839 }
 840
 841 static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info)
 842 {
 843         unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0;
 844         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 845         struct sk_buff *skb;
 846         int err = -ENOBUFS;
 847
 848         skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any());
 849         if (!skb)
 850                 goto errout;
 851
 852         err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags);
 853         if (err < 0) {
 854                 /* -EMSGSIZE implies BUG in nh_nlmsg_size() */
 855                 WARN_ON(err == -EMSGSIZE);
 856                 kfree_skb(skb);
 857                 goto errout;
 858         }
 859
 860         rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP,
 861                     info->nlh, gfp_any());
 862         return;
 863 errout:
 864         if (err < 0)
 865                 rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err);
 866 }
 867
 868 static unsigned long nh_res_bucket_used_time(const struct nh_res_bucket *bucket)
 869 {
 870         return (unsigned long)atomic_long_read(&bucket->used_time);
 871 }
 872
 873 static unsigned long
 874 nh_res_bucket_idle_point(const struct nh_res_table *res_table,
 875                          const struct nh_res_bucket *bucket,
 876                          unsigned long now)
 877 {
 878         unsigned long time = nh_res_bucket_used_time(bucket);
 879
 880         /* Bucket was not used since it was migrated. The idle time is now. */
 881         if (time == bucket->migrated_time)
 882                 return now;
 883
 884         return time + res_table->idle_timer;
 885 }
 886
 887 static unsigned long
 888 nh_res_table_unb_point(const struct nh_res_table *res_table)
 889 {
 890         return res_table->unbalanced_since + res_table->unbalanced_timer;
 891 }
 892
 893 static void nh_res_bucket_set_idle(const struct nh_res_table *res_table,
 894                                    struct nh_res_bucket *bucket)
 895 {
 896         unsigned long now = jiffies;
 897
 898         atomic_long_set(&bucket->used_time, (long)now);
 899         bucket->migrated_time = now;
 900 }
 901
 902 static void nh_res_bucket_set_busy(struct nh_res_bucket *bucket)
 903 {
 904         atomic_long_set(&bucket->used_time, (long)jiffies);
 905 }
 906
 907 static clock_t nh_res_bucket_idle_time(const struct nh_res_bucket *bucket)
 908 {
 909         unsigned long used_time = nh_res_bucket_used_time(bucket);
 910
 911         return jiffies_delta_to_clock_t(jiffies - used_time);
 912 }
 913
 914 static int nh_fill_res_bucket(struct sk_buff *skb, struct nexthop *nh,
 915                               struct nh_res_bucket *bucket, u16 bucket_index,
 916                               int event, u32 portid, u32 seq,
 917                               unsigned int nlflags,
 918                               struct netlink_ext_ack *extack)
 919 {
 920         struct nh_grp_entry *nhge = nh_res_dereference(bucket->nh_entry);
 921         struct nlmsghdr *nlh;
 922         struct nlattr *nest;
 923         struct nhmsg *nhm;
 924
 925         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
 926         if (!nlh)
 927                 return -EMSGSIZE;
 928
 929         nhm = nlmsg_data(nlh);
 930         nhm->nh_family = AF_UNSPEC;
 931         nhm->nh_flags = bucket->nh_flags;
 932         nhm->nh_protocol = nh->protocol;
 933         nhm->nh_scope = 0;
 934         nhm->resvd = 0;
 935
 936         if (nla_put_u32(skb, NHA_ID, nh->id))
 937                 goto nla_put_failure;
 938
 939         nest = nla_nest_start(skb, NHA_RES_BUCKET);
 940         if (!nest)
 941                 goto nla_put_failure;
 942
 943         if (nla_put_u16(skb, NHA_RES_BUCKET_INDEX, bucket_index) ||
 944             nla_put_u32(skb, NHA_RES_BUCKET_NH_ID, nhge->nh->id) ||
 945             nla_put_u64_64bit(skb, NHA_RES_BUCKET_IDLE_TIME,
 946                               nh_res_bucket_idle_time(bucket),
 947                               NHA_RES_BUCKET_PAD))
 948                 goto nla_put_failure_nest;
 949
 950         nla_nest_end(skb, nest);
 951         nlmsg_end(skb, nlh);
 952         return 0;
 953
 954 nla_put_failure_nest:
 955         nla_nest_cancel(skb, nest);
 956 nla_put_failure:
 957         nlmsg_cancel(skb, nlh);
 958         return -EMSGSIZE;
 959 }
 960
 961 static void nexthop_bucket_notify(struct nh_res_table *res_table,
 962                                   u16 bucket_index)
 963 {
 964         struct nh_res_bucket *bucket = &res_table->nh_buckets[bucket_index];
 965         struct nh_grp_entry *nhge = nh_res_dereference(bucket->nh_entry);
 966         struct nexthop *nh = nhge->nh_parent;
 967         struct sk_buff *skb;
 968         int err = -ENOBUFS;
 969
 970         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 971         if (!skb)
 972                 goto errout;
 973
 974         err = nh_fill_res_bucket(skb, nh, bucket, bucket_index,
 975                                  RTM_NEWNEXTHOPBUCKET, 0, 0, NLM_F_REPLACE,
 976                                  NULL);
 977         if (err < 0) {
 978                 kfree_skb(skb);
 979                 goto errout;
 980         }
 981
 982         rtnl_notify(skb, nh->net, 0, RTNLGRP_NEXTHOP, NULL, GFP_KERNEL);
 983         return;
 984 errout:
 985         if (err < 0)
 986                 rtnl_set_sk_err(nh->net, RTNLGRP_NEXTHOP, err);
 987 }
 988
 989 static bool valid_group_nh(struct nexthop *nh, unsigned int npaths,
 990                            bool *is_fdb, struct netlink_ext_ack *extack)
 991 {
 992         if (nh->is_group) {
 993                 struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 994
 995                 /* Nesting groups within groups is not supported. */
 996                 if (nhg->hash_threshold) {
 997                         NL_SET_ERR_MSG(extack,
 998                                        "Hash-threshold group can not be a nexthop within a group");
 999                         return false;
1000                 }
1001                 if (nhg->resilient) {
1002                         NL_SET_ERR_MSG(extack,
1003                                        "Resilient group can not be a nexthop within a group");
1004                         return false;
1005                 }
1006                 *is_fdb = nhg->fdb_nh;
1007         } else {
1008                 struct nh_info *nhi = rtnl_dereference(nh->nh_info);
1009
1010                 if (nhi->reject_nh && npaths > 1) {
1011                         NL_SET_ERR_MSG(extack,
1012                                        "Blackhole nexthop can not be used in a group with more than 1 path");
1013                         return false;
1014                 }
1015                 *is_fdb = nhi->fdb_nh;
1016         }
1017
1018         return true;
1019 }
1020
1021 static int nh_check_attr_fdb_group(struct nexthop *nh, u8 *nh_family,
1022                                    struct netlink_ext_ack *extack)
1023 {
1024         struct nh_info *nhi;
1025
1026         nhi = rtnl_dereference(nh->nh_info);
1027
1028         if (!nhi->fdb_nh) {
1029                 NL_SET_ERR_MSG(extack, "FDB nexthop group can only have fdb nexthops");
1030                 return -EINVAL;
1031         }
1032
1033         if (*nh_family == AF_UNSPEC) {
1034                 *nh_family = nhi->family;
1035         } else if (*nh_family != nhi->family) {
1036                 NL_SET_ERR_MSG(extack, "FDB nexthop group cannot have mixed family nexthops");
1037                 return -EINVAL;
1038         }
1039
1040         return 0;
1041 }
1042
1043 static int nh_check_attr_group(struct net *net,
1044                                struct nlattr *tb[], size_t tb_size,
1045                                u16 nh_grp_type, struct netlink_ext_ack *extack)
1046 {
1047         unsigned int len = nla_len(tb[NHA_GROUP]);
1048         u8 nh_family = AF_UNSPEC;
1049         struct nexthop_grp *nhg;
1050         unsigned int i, j;
1051         u8 nhg_fdb = 0;
1052
1053         if (!len || len & (sizeof(struct nexthop_grp) - 1)) {
1054                 NL_SET_ERR_MSG(extack,
1055                                "Invalid length for nexthop group attribute");
1056                 return -EINVAL;
1057         }
1058
1059         /* convert len to number of nexthop ids */
1060         len /= sizeof(*nhg);
1061
1062         nhg = nla_data(tb[NHA_GROUP]);
1063         for (i = 0; i < len; ++i) {
1064                 if (nhg[i].resvd1 || nhg[i].resvd2) {
1065                         NL_SET_ERR_MSG(extack, "Reserved fields in nexthop_grp must be 0");
1066                         return -EINVAL;
1067                 }
1068                 if (nhg[i].weight > 254) {
1069                         NL_SET_ERR_MSG(extack, "Invalid value for weight");
1070                         return -EINVAL;
1071                 }
1072                 for (j = i + 1; j < len; ++j) {
1073                         if (nhg[i].id == nhg[j].id) {
1074                                 NL_SET_ERR_MSG(extack, "Nexthop id can not be used twice in a group");
1075                                 return -EINVAL;
1076                         }
1077                 }
1078         }
1079
1080         if (tb[NHA_FDB])
1081                 nhg_fdb = 1;
1082         nhg = nla_data(tb[NHA_GROUP]);
1083         for (i = 0; i < len; ++i) {
1084                 struct nexthop *nh;
1085                 bool is_fdb_nh;
1086
1087                 nh = nexthop_find_by_id(net, nhg[i].id);
1088                 if (!nh) {
1089                         NL_SET_ERR_MSG(extack, "Invalid nexthop id");
1090                         return -EINVAL;
1091                 }
1092                 if (!valid_group_nh(nh, len, &is_fdb_nh, extack))
1093                         return -EINVAL;
1094
1095                 if (nhg_fdb && nh_check_attr_fdb_group(nh, &nh_family, extack))
1096                         return -EINVAL;
1097
1098                 if (!nhg_fdb && is_fdb_nh) {
1099                         NL_SET_ERR_MSG(extack, "Non FDB nexthop group cannot have fdb nexthops");
1100                         return -EINVAL;
1101                 }
1102         }
1103         for (i = NHA_GROUP_TYPE + 1; i < tb_size; ++i) {
1104                 if (!tb[i])
1105                         continue;
1106                 switch (i) {
1107                 case NHA_FDB:
1108                         continue;
1109                 case NHA_RES_GROUP:
1110                         if (nh_grp_type == NEXTHOP_GRP_TYPE_RES)
1111                                 continue;
1112                         break;
1113                 }
1114                 NL_SET_ERR_MSG(extack,
1115                                "No other attributes can be set in nexthop groups");
1116                 return -EINVAL;
1117         }
1118
1119         return 0;
1120 }
1121
1122 static bool ipv6_good_nh(const struct fib6_nh *nh)
1123 {
1124         int state = NUD_REACHABLE;
1125         struct neighbour *n;
1126
1127         rcu_read_lock();
1128
1129         n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6);
1130         if (n)
1131                 state = READ_ONCE(n->nud_state);
1132
1133         rcu_read_unlock();
1134
1135         return !!(state & NUD_VALID);
1136 }
1137
1138 static bool ipv4_good_nh(const struct fib_nh *nh)
1139 {
1140         int state = NUD_REACHABLE;
1141         struct neighbour *n;
1142
1143         rcu_read_lock();
1144
1145         n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
1146                                       (__force u32)nh->fib_nh_gw4);
1147         if (n)
1148                 state = READ_ONCE(n->nud_state);
1149
1150         rcu_read_unlock();
1151
1152         return !!(state & NUD_VALID);
1153 }
1154
1155 static bool nexthop_is_good_nh(const struct nexthop *nh)
1156 {
1157         struct nh_info *nhi = rcu_dereference(nh->nh_info);
1158
1159         switch (nhi->family) {
1160         case AF_INET:
1161                 return ipv4_good_nh(&nhi->fib_nh);
1162         case AF_INET6:
1163                 return ipv6_good_nh(&nhi->fib6_nh);
1164         }
1165
1166         return false;
1167 }
1168
1169 static struct nexthop *nexthop_select_path_fdb(struct nh_group *nhg, int hash)
1170 {
1171         int i;
1172
1173         for (i = 0; i < nhg->num_nh; i++) {
1174                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1175
1176                 if (hash > atomic_read(&nhge->hthr.upper_bound))
1177                         continue;
1178
1179                 return nhge->nh;
1180         }
1181
1182         WARN_ON_ONCE(1);
1183         return NULL;
1184 }
1185
1186 static struct nexthop *nexthop_select_path_hthr(struct nh_group *nhg, int hash)
1187 {
1188         struct nexthop *rc = NULL;
1189         int i;
1190
1191         if (nhg->fdb_nh)
1192                 return nexthop_select_path_fdb(nhg, hash);
1193
1194         for (i = 0; i < nhg->num_nh; ++i) {
1195                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1196
1197                 /* nexthops always check if it is good and does
1198                  * not rely on a sysctl for this behavior
1199                  */
1200                 if (!nexthop_is_good_nh(nhge->nh))
1201                         continue;
1202
1203                 if (!rc)
1204                         rc = nhge->nh;
1205
1206                 if (hash > atomic_read(&nhge->hthr.upper_bound))
1207                         continue;
1208
1209                 return nhge->nh;
1210         }
1211
1212         return rc ? : nhg->nh_entries[0].nh;
1213 }
1214
1215 static struct nexthop *nexthop_select_path_res(struct nh_group *nhg, int hash)
1216 {
1217         struct nh_res_table *res_table = rcu_dereference(nhg->res_table);
1218         u16 bucket_index = hash % res_table->num_nh_buckets;
1219         struct nh_res_bucket *bucket;
1220         struct nh_grp_entry *nhge;
1221
1222         /* nexthop_select_path() is expected to return a non-NULL value, so
1223          * skip protocol validation and just hand out whatever there is.
1224          */
1225         bucket = &res_table->nh_buckets[bucket_index];
1226         nh_res_bucket_set_busy(bucket);
1227         nhge = rcu_dereference(bucket->nh_entry);
1228         return nhge->nh;
1229 }
1230
1231 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash)
1232 {
1233         struct nh_group *nhg;
1234
1235         if (!nh->is_group)
1236                 return nh;
1237
1238         nhg = rcu_dereference(nh->nh_grp);
1239         if (nhg->hash_threshold)
1240                 return nexthop_select_path_hthr(nhg, hash);
1241         else if (nhg->resilient)
1242                 return nexthop_select_path_res(nhg, hash);
1243
1244         /* Unreachable. */
1245         return NULL;
1246 }
1247 EXPORT_SYMBOL_GPL(nexthop_select_path);
1248
1249 int nexthop_for_each_fib6_nh(struct nexthop *nh,
1250                              int (*cb)(struct fib6_nh *nh, void *arg),
1251                              void *arg)
1252 {
1253         struct nh_info *nhi;
1254         int err;
1255
1256         if (nh->is_group) {
1257                 struct nh_group *nhg;
1258                 int i;
1259
1260                 nhg = rcu_dereference_rtnl(nh->nh_grp);
1261                 for (i = 0; i < nhg->num_nh; i++) {
1262                         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1263
1264                         nhi = rcu_dereference_rtnl(nhge->nh->nh_info);
1265                         err = cb(&nhi->fib6_nh, arg);
1266                         if (err)
1267                                 return err;
1268                 }
1269         } else {
1270                 nhi = rcu_dereference_rtnl(nh->nh_info);
1271                 err = cb(&nhi->fib6_nh, arg);
1272                 if (err)
1273                         return err;
1274         }
1275
1276         return 0;
1277 }
1278 EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh);
1279
1280 static int check_src_addr(const struct in6_addr *saddr,
1281                           struct netlink_ext_ack *extack)
1282 {
1283         if (!ipv6_addr_any(saddr)) {
1284                 NL_SET_ERR_MSG(extack, "IPv6 routes using source address can not use nexthop objects");
1285                 return -EINVAL;
1286         }
1287         return 0;
1288 }
1289
1290 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
1291                        struct netlink_ext_ack *extack)
1292 {
1293         struct nh_info *nhi;
1294         bool is_fdb_nh;
1295
1296         /* fib6_src is unique to a fib6_info and limits the ability to cache
1297          * routes in fib6_nh within a nexthop that is potentially shared
1298          * across multiple fib entries. If the config wants to use source
1299          * routing it can not use nexthop objects. mlxsw also does not allow
1300          * fib6_src on routes.
1301          */
1302         if (cfg && check_src_addr(&cfg->fc_src, extack) < 0)
1303                 return -EINVAL;
1304
1305         if (nh->is_group) {
1306                 struct nh_group *nhg;
1307
1308                 nhg = rtnl_dereference(nh->nh_grp);
1309                 if (nhg->has_v4)
1310                         goto no_v4_nh;
1311                 is_fdb_nh = nhg->fdb_nh;
1312         } else {
1313                 nhi = rtnl_dereference(nh->nh_info);
1314                 if (nhi->family == AF_INET)
1315                         goto no_v4_nh;
1316                 is_fdb_nh = nhi->fdb_nh;
1317         }
1318
1319         if (is_fdb_nh) {
1320                 NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1321                 return -EINVAL;
1322         }
1323
1324         return 0;
1325 no_v4_nh:
1326         NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop");
1327         return -EINVAL;
1328 }
1329 EXPORT_SYMBOL_GPL(fib6_check_nexthop);
1330
1331 /* if existing nexthop has ipv6 routes linked to it, need
1332  * to verify this new spec works with ipv6
1333  */
1334 static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new,
1335                               struct netlink_ext_ack *extack)
1336 {
1337         struct fib6_info *f6i;
1338
1339         if (list_empty(&old->f6i_list))
1340                 return 0;
1341
1342         list_for_each_entry(f6i, &old->f6i_list, nh_list) {
1343                 if (check_src_addr(&f6i->fib6_src.addr, extack) < 0)
1344                         return -EINVAL;
1345         }
1346
1347         return fib6_check_nexthop(new, NULL, extack);
1348 }
1349
1350 static int nexthop_check_scope(struct nh_info *nhi, u8 scope,
1351                                struct netlink_ext_ack *extack)
1352 {
1353         if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {
1354                 NL_SET_ERR_MSG(extack,
1355                                "Route with host scope can not have a gateway");
1356                 return -EINVAL;
1357         }
1358
1359         if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {
1360                 NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");
1361                 return -EINVAL;
1362         }
1363
1364         return 0;
1365 }
1366
1367 /* Invoked by fib add code to verify nexthop by id is ok with
1368  * config for prefix; parts of fib_check_nh not done when nexthop
1369  * object is used.
1370  */
1371 int fib_check_nexthop(struct nexthop *nh, u8 scope,
1372                       struct netlink_ext_ack *extack)
1373 {
1374         struct nh_info *nhi;
1375         int err = 0;
1376
1377         if (nh->is_group) {
1378                 struct nh_group *nhg;
1379
1380                 nhg = rtnl_dereference(nh->nh_grp);
1381                 if (nhg->fdb_nh) {
1382                         NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1383                         err = -EINVAL;
1384                         goto out;
1385                 }
1386
1387                 if (scope == RT_SCOPE_HOST) {
1388                         NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");
1389                         err = -EINVAL;
1390                         goto out;
1391                 }
1392
1393                 /* all nexthops in a group have the same scope */
1394                 nhi = rtnl_dereference(nhg->nh_entries[0].nh->nh_info);
1395                 err = nexthop_check_scope(nhi, scope, extack);
1396         } else {
1397                 nhi = rtnl_dereference(nh->nh_info);
1398                 if (nhi->fdb_nh) {
1399                         NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1400                         err = -EINVAL;
1401                         goto out;
1402                 }
1403                 err = nexthop_check_scope(nhi, scope, extack);
1404         }
1405
1406 out:
1407         return err;
1408 }
1409
1410 static int fib_check_nh_list(struct nexthop *old, struct nexthop *new,
1411                              struct netlink_ext_ack *extack)
1412 {
1413         struct fib_info *fi;
1414
1415         list_for_each_entry(fi, &old->fi_list, nh_list) {
1416                 int err;
1417
1418                 err = fib_check_nexthop(new, fi->fib_scope, extack);
1419                 if (err)
1420                         return err;
1421         }
1422         return 0;
1423 }
1424
1425 static bool nh_res_nhge_is_balanced(const struct nh_grp_entry *nhge)
1426 {
1427         return nhge->res.count_buckets == nhge->res.wants_buckets;
1428 }
1429
1430 static bool nh_res_nhge_is_ow(const struct nh_grp_entry *nhge)
1431 {
1432         return nhge->res.count_buckets > nhge->res.wants_buckets;
1433 }
1434
1435 static bool nh_res_nhge_is_uw(const struct nh_grp_entry *nhge)
1436 {
1437         return nhge->res.count_buckets < nhge->res.wants_buckets;
1438 }
1439
1440 static bool nh_res_table_is_balanced(const struct nh_res_table *res_table)
1441 {
1442         return list_empty(&res_table->uw_nh_entries);
1443 }
1444
1445 static void nh_res_bucket_unset_nh(struct nh_res_bucket *bucket)
1446 {
1447         struct nh_grp_entry *nhge;
1448
1449         if (bucket->occupied) {
1450                 nhge = nh_res_dereference(bucket->nh_entry);
1451                 nhge->res.count_buckets--;
1452                 bucket->occupied = false;
1453         }
1454 }
1455
1456 static void nh_res_bucket_set_nh(struct nh_res_bucket *bucket,
1457                                  struct nh_grp_entry *nhge)
1458 {
1459         nh_res_bucket_unset_nh(bucket);
1460
1461         bucket->occupied = true;
1462         rcu_assign_pointer(bucket->nh_entry, nhge);
1463         nhge->res.count_buckets++;
1464 }
1465
1466 static bool nh_res_bucket_should_migrate(struct nh_res_table *res_table,
1467                                          struct nh_res_bucket *bucket,
1468                                          unsigned long *deadline, bool *force)
1469 {
1470         unsigned long now = jiffies;
1471         struct nh_grp_entry *nhge;
1472         unsigned long idle_point;
1473
1474         if (!bucket->occupied) {
1475                 /* The bucket is not occupied, its NHGE pointer is either
1476                  * NULL or obsolete. We _have to_ migrate: set force.
1477                  */
1478                 *force = true;
1479                 return true;
1480         }
1481
1482         nhge = nh_res_dereference(bucket->nh_entry);
1483
1484         /* If the bucket is populated by an underweight or balanced
1485          * nexthop, do not migrate.
1486          */
1487         if (!nh_res_nhge_is_ow(nhge))
1488                 return false;
1489
1490         /* At this point we know that the bucket is populated with an
1491          * overweight nexthop. It needs to be migrated to a new nexthop if
1492          * the idle timer of unbalanced timer expired.
1493          */
1494
1495         idle_point = nh_res_bucket_idle_point(res_table, bucket, now);
1496         if (time_after_eq(now, idle_point)) {
1497                 /* The bucket is idle. We _can_ migrate: unset force. */
1498                 *force = false;
1499                 return true;
1500         }
1501
1502         /* Unbalanced timer of 0 means "never force". */
1503         if (res_table->unbalanced_timer) {
1504                 unsigned long unb_point;
1505
1506                 unb_point = nh_res_table_unb_point(res_table);
1507                 if (time_after(now, unb_point)) {
1508                         /* The bucket is not idle, but the unbalanced timer
1509                          * expired. We _can_ migrate, but set force anyway,
1510                          * so that drivers know to ignore activity reports
1511                          * from the HW.
1512                          */
1513                         *force = true;
1514                         return true;
1515                 }
1516
1517                 nh_res_time_set_deadline(unb_point, deadline);
1518         }
1519
1520         nh_res_time_set_deadline(idle_point, deadline);
1521         return false;
1522 }
1523
1524 static bool nh_res_bucket_migrate(struct nh_res_table *res_table,
1525                                   u16 bucket_index, bool notify,
1526                                   bool notify_nl, bool force)
1527 {
1528         struct nh_res_bucket *bucket = &res_table->nh_buckets[bucket_index];
1529         struct nh_grp_entry *new_nhge;
1530         struct netlink_ext_ack extack;
1531         int err;
1532
1533         new_nhge = list_first_entry_or_null(&res_table->uw_nh_entries,
1534                                             struct nh_grp_entry,
1535                                             res.uw_nh_entry);
1536         if (WARN_ON_ONCE(!new_nhge))
1537                 /* If this function is called, "bucket" is either not
1538                  * occupied, or it belongs to a next hop that is
1539                  * overweight. In either case, there ought to be a
1540                  * corresponding underweight next hop.
1541                  */
1542                 return false;
1543
1544         if (notify) {
1545                 struct nh_grp_entry *old_nhge;
1546
1547                 old_nhge = nh_res_dereference(bucket->nh_entry);
1548                 err = call_nexthop_res_bucket_notifiers(res_table->net,
1549                                                         res_table->nhg_id,
1550                                                         bucket_index, force,
1551                                                         old_nhge->nh,
1552                                                         new_nhge->nh, &extack);
1553                 if (err) {
1554                         pr_err_ratelimited("%s\n", extack._msg);
1555                         if (!force)
1556                                 return false;
1557                         /* It is not possible to veto a forced replacement, so
1558                          * just clear the hardware flags from the nexthop
1559                          * bucket to indicate to user space that this bucket is
1560                          * not correctly populated in hardware.
1561                          */
1562                         bucket->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
1563                 }
1564         }
1565
1566         nh_res_bucket_set_nh(bucket, new_nhge);
1567         nh_res_bucket_set_idle(res_table, bucket);
1568
1569         if (notify_nl)
1570                 nexthop_bucket_notify(res_table, bucket_index);
1571
1572         if (nh_res_nhge_is_balanced(new_nhge))
1573                 list_del(&new_nhge->res.uw_nh_entry);
1574         return true;
1575 }
1576
1577 #define NH_RES_UPKEEP_DW_MINIMUM_INTERVAL (HZ / 2)
1578
1579 static void nh_res_table_upkeep(struct nh_res_table *res_table,
1580                                 bool notify, bool notify_nl)
1581 {
1582         unsigned long now = jiffies;
1583         unsigned long deadline;
1584         u16 i;
1585
1586         /* Deadline is the next time that upkeep should be run. It is the
1587          * earliest time at which one of the buckets might be migrated.
1588          * Start at the most pessimistic estimate: either unbalanced_timer
1589          * from now, or if there is none, idle_timer from now. For each
1590          * encountered time point, call nh_res_time_set_deadline() to
1591          * refine the estimate.
1592          */
1593         if (res_table->unbalanced_timer)
1594                 deadline = now + res_table->unbalanced_timer;
1595         else
1596                 deadline = now + res_table->idle_timer;
1597
1598         for (i = 0; i < res_table->num_nh_buckets; i++) {
1599                 struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
1600                 bool force;
1601
1602                 if (nh_res_bucket_should_migrate(res_table, bucket,
1603                                                  &deadline, &force)) {
1604                         if (!nh_res_bucket_migrate(res_table, i, notify,
1605                                                    notify_nl, force)) {
1606                                 unsigned long idle_point;
1607
1608                                 /* A driver can override the migration
1609                                  * decision if the HW reports that the
1610                                  * bucket is actually not idle. Therefore
1611                                  * remark the bucket as busy again and
1612                                  * update the deadline.
1613                                  */
1614                                 nh_res_bucket_set_busy(bucket);
1615                                 idle_point = nh_res_bucket_idle_point(res_table,
1616                                                                       bucket,
1617                                                                       now);
1618                                 nh_res_time_set_deadline(idle_point, &deadline);
1619                         }
1620                 }
1621         }
1622
1623         /* If the group is still unbalanced, schedule the next upkeep to
1624          * either the deadline computed above, or the minimum deadline,
1625          * whichever comes later.
1626          */
1627         if (!nh_res_table_is_balanced(res_table)) {
1628                 unsigned long now = jiffies;
1629                 unsigned long min_deadline;
1630
1631                 min_deadline = now + NH_RES_UPKEEP_DW_MINIMUM_INTERVAL;
1632                 if (time_before(deadline, min_deadline))
1633                         deadline = min_deadline;
1634
1635                 queue_delayed_work(system_power_efficient_wq,
1636                                    &res_table->upkeep_dw, deadline - now);
1637         }
1638 }
1639
1640 static void nh_res_table_upkeep_dw(struct work_struct *work)
1641 {
1642         struct delayed_work *dw = to_delayed_work(work);
1643         struct nh_res_table *res_table;
1644
1645         res_table = container_of(dw, struct nh_res_table, upkeep_dw);
1646         nh_res_table_upkeep(res_table, true, true);
1647 }
1648
1649 static void nh_res_table_cancel_upkeep(struct nh_res_table *res_table)
1650 {
1651         cancel_delayed_work_sync(&res_table->upkeep_dw);
1652 }
1653
1654 static void nh_res_group_rebalance(struct nh_group *nhg,
1655                                    struct nh_res_table *res_table)
1656 {
1657         int prev_upper_bound = 0;
1658         int total = 0;
1659         int w = 0;
1660         int i;
1661
1662         INIT_LIST_HEAD(&res_table->uw_nh_entries);
1663
1664         for (i = 0; i < nhg->num_nh; ++i)
1665                 total += nhg->nh_entries[i].weight;
1666
1667         for (i = 0; i < nhg->num_nh; ++i) {
1668                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1669                 int upper_bound;
1670
1671                 w += nhge->weight;
1672                 upper_bound = DIV_ROUND_CLOSEST(res_table->num_nh_buckets * w,
1673                                                 total);
1674                 nhge->res.wants_buckets = upper_bound - prev_upper_bound;
1675                 prev_upper_bound = upper_bound;
1676
1677                 if (nh_res_nhge_is_uw(nhge)) {
1678                         if (list_empty(&res_table->uw_nh_entries))
1679                                 res_table->unbalanced_since = jiffies;
1680                         list_add(&nhge->res.uw_nh_entry,
1681                                  &res_table->uw_nh_entries);
1682                 }
1683         }
1684 }
1685
1686 /* Migrate buckets in res_table so that they reference NHGE's from NHG with
1687  * the right NH ID. Set those buckets that do not have a corresponding NHGE
1688  * entry in NHG as not occupied.
1689  */
1690 static void nh_res_table_migrate_buckets(struct nh_res_table *res_table,
1691                                          struct nh_group *nhg)
1692 {
1693         u16 i;
1694
1695         for (i = 0; i < res_table->num_nh_buckets; i++) {
1696                 struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
1697                 u32 id = rtnl_dereference(bucket->nh_entry)->nh->id;
1698                 bool found = false;
1699                 int j;
1700
1701                 for (j = 0; j < nhg->num_nh; j++) {
1702                         struct nh_grp_entry *nhge = &nhg->nh_entries[j];
1703
1704                         if (nhge->nh->id == id) {
1705                                 nh_res_bucket_set_nh(bucket, nhge);
1706                                 found = true;
1707                                 break;
1708                         }
1709                 }
1710
1711                 if (!found)
1712                         nh_res_bucket_unset_nh(bucket);
1713         }
1714 }
1715
1716 static void replace_nexthop_grp_res(struct nh_group *oldg,
1717                                     struct nh_group *newg)
1718 {
1719         /* For NH group replacement, the new NHG might only have a stub
1720          * hash table with 0 buckets, because the number of buckets was not
1721          * specified. For NH removal, oldg and newg both reference the same
1722          * res_table. So in any case, in the following, we want to work
1723          * with oldg->res_table.
1724          */
1725         struct nh_res_table *old_res_table = rtnl_dereference(oldg->res_table);
1726         unsigned long prev_unbalanced_since = old_res_table->unbalanced_since;
1727         bool prev_has_uw = !list_empty(&old_res_table->uw_nh_entries);
1728
1729         nh_res_table_cancel_upkeep(old_res_table);
1730         nh_res_table_migrate_buckets(old_res_table, newg);
1731         nh_res_group_rebalance(newg, old_res_table);
1732         if (prev_has_uw && !list_empty(&old_res_table->uw_nh_entries))
1733                 old_res_table->unbalanced_since = prev_unbalanced_since;
1734         nh_res_table_upkeep(old_res_table, true, false);
1735 }
1736
1737 static void nh_hthr_group_rebalance(struct nh_group *nhg)
1738 {
1739         int total = 0;
1740         int w = 0;
1741         int i;
1742
1743         for (i = 0; i < nhg->num_nh; ++i)
1744                 total += nhg->nh_entries[i].weight;
1745
1746         for (i = 0; i < nhg->num_nh; ++i) {
1747                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1748                 int upper_bound;
1749
1750                 w += nhge->weight;
1751                 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1;
1752                 atomic_set(&nhge->hthr.upper_bound, upper_bound);
1753         }
1754 }
1755
1756 static void remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge,
1757                                 struct nl_info *nlinfo)
1758 {
1759         struct nh_grp_entry *nhges, *new_nhges;
1760         struct nexthop *nhp = nhge->nh_parent;
1761         struct netlink_ext_ack extack;
1762         struct nexthop *nh = nhge->nh;
1763         struct nh_group *nhg, *newg;
1764         int i, j, err;
1765
1766         WARN_ON(!nh);
1767
1768         nhg = rtnl_dereference(nhp->nh_grp);
1769         newg = nhg->spare;
1770
1771         /* last entry, keep it visible and remove the parent */
1772         if (nhg->num_nh == 1) {
1773                 remove_nexthop(net, nhp, nlinfo);
1774                 return;
1775         }
1776
1777         newg->has_v4 = false;
1778         newg->is_multipath = nhg->is_multipath;
1779         newg->hash_threshold = nhg->hash_threshold;
1780         newg->resilient = nhg->resilient;
1781         newg->fdb_nh = nhg->fdb_nh;
1782         newg->num_nh = nhg->num_nh;
1783
1784         /* copy old entries to new except the one getting removed */
1785         nhges = nhg->nh_entries;
1786         new_nhges = newg->nh_entries;
1787         for (i = 0, j = 0; i < nhg->num_nh; ++i) {
1788                 struct nh_info *nhi;
1789
1790                 /* current nexthop getting removed */
1791                 if (nhg->nh_entries[i].nh == nh) {
1792                         newg->num_nh--;
1793                         continue;
1794                 }
1795
1796                 nhi = rtnl_dereference(nhges[i].nh->nh_info);
1797                 if (nhi->family == AF_INET)
1798                         newg->has_v4 = true;
1799
1800                 list_del(&nhges[i].nh_list);
1801                 new_nhges[j].nh_parent = nhges[i].nh_parent;
1802                 new_nhges[j].nh = nhges[i].nh;
1803                 new_nhges[j].weight = nhges[i].weight;
1804                 list_add(&new_nhges[j].nh_list, &new_nhges[j].nh->grp_list);
1805                 j++;
1806         }
1807
1808         if (newg->hash_threshold)
1809                 nh_hthr_group_rebalance(newg);
1810         else if (newg->resilient)
1811                 replace_nexthop_grp_res(nhg, newg);
1812
1813         rcu_assign_pointer(nhp->nh_grp, newg);
1814
1815         list_del(&nhge->nh_list);
1816         nexthop_put(nhge->nh);
1817
1818         /* Removal of a NH from a resilient group is notified through
1819          * bucket notifications.
1820          */
1821         if (newg->hash_threshold) {
1822                 err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, nhp,
1823                                              &extack);
1824                 if (err)
1825                         pr_err("%s\n", extack._msg);
1826         }
1827
1828         if (nlinfo)
1829                 nexthop_notify(RTM_NEWNEXTHOP, nhp, nlinfo);
1830 }
1831
1832 static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh,
1833                                        struct nl_info *nlinfo)
1834 {
1835         struct nh_grp_entry *nhge, *tmp;
1836
1837         list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list)
1838                 remove_nh_grp_entry(net, nhge, nlinfo);
1839
1840         /* make sure all see the newly published array before releasing rtnl */
1841         synchronize_net();
1842 }
1843
1844 static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo)
1845 {
1846         struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
1847         struct nh_res_table *res_table;
1848         int i, num_nh = nhg->num_nh;
1849
1850         for (i = 0; i < num_nh; ++i) {
1851                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1852
1853                 if (WARN_ON(!nhge->nh))
1854                         continue;
1855
1856                 list_del_init(&nhge->nh_list);
1857         }
1858
1859         if (nhg->resilient) {
1860                 res_table = rtnl_dereference(nhg->res_table);
1861                 nh_res_table_cancel_upkeep(res_table);
1862         }
1863 }
1864
1865 /* not called for nexthop replace */
1866 static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
1867 {
1868         struct fib6_info *f6i, *tmp;
1869         bool do_flush = false;
1870         struct fib_info *fi;
1871
1872         list_for_each_entry(fi, &nh->fi_list, nh_list) {
1873                 fi->fib_flags |= RTNH_F_DEAD;
1874                 do_flush = true;
1875         }
1876         if (do_flush)
1877                 fib_flush(net);
1878
1879         /* ip6_del_rt removes the entry from this list hence the _safe */
1880         list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) {
1881                 /* __ip6_del_rt does a release, so do a hold here */
1882                 fib6_info_hold(f6i);
1883                 ipv6_stub->ip6_del_rt(net, f6i,
1884                                       !READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
1885         }
1886 }
1887
1888 static void __remove_nexthop(struct net *net, struct nexthop *nh,
1889                              struct nl_info *nlinfo)
1890 {
1891         __remove_nexthop_fib(net, nh);
1892
1893         if (nh->is_group) {
1894                 remove_nexthop_group(nh, nlinfo);
1895         } else {
1896                 struct nh_info *nhi;
1897
1898                 nhi = rtnl_dereference(nh->nh_info);
1899                 if (nhi->fib_nhc.nhc_dev)
1900                         hlist_del(&nhi->dev_hash);
1901
1902                 remove_nexthop_from_groups(net, nh, nlinfo);
1903         }
1904 }
1905
1906 static void remove_nexthop(struct net *net, struct nexthop *nh,
1907                            struct nl_info *nlinfo)
1908 {
1909         call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh, NULL);
1910
1911         /* remove from the tree */
1912         rb_erase(&nh->rb_node, &net->nexthop.rb_root);
1913
1914         if (nlinfo)
1915                 nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
1916
1917         __remove_nexthop(net, nh, nlinfo);
1918         nh_base_seq_inc(net);
1919
1920         nexthop_put(nh);
1921 }
1922
1923 /* if any FIB entries reference this nexthop, any dst entries
1924  * need to be regenerated
1925  */
1926 static void nh_rt_cache_flush(struct net *net, struct nexthop *nh,
1927                               struct nexthop *replaced_nh)
1928 {
1929         struct fib6_info *f6i;
1930         struct nh_group *nhg;
1931         int i;
1932
1933         if (!list_empty(&nh->fi_list))
1934                 rt_cache_flush(net);
1935
1936         list_for_each_entry(f6i, &nh->f6i_list, nh_list)
1937                 ipv6_stub->fib6_update_sernum(net, f6i);
1938
1939         /* if an IPv6 group was replaced, we have to release all old
1940          * dsts to make sure all refcounts are released
1941          */
1942         if (!replaced_nh->is_group)
1943                 return;
1944
1945         nhg = rtnl_dereference(replaced_nh->nh_grp);
1946         for (i = 0; i < nhg->num_nh; i++) {
1947                 struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1948                 struct nh_info *nhi = rtnl_dereference(nhge->nh->nh_info);
1949
1950                 if (nhi->family == AF_INET6)
1951                         ipv6_stub->fib6_nh_release_dsts(&nhi->fib6_nh);
1952         }
1953 }
1954
1955 static int replace_nexthop_grp(struct net *net, struct nexthop *old,
1956                                struct nexthop *new, const struct nh_config *cfg,
1957                                struct netlink_ext_ack *extack)
1958 {
1959         struct nh_res_table *tmp_table = NULL;
1960         struct nh_res_table *new_res_table;
1961         struct nh_res_table *old_res_table;
1962         struct nh_group *oldg, *newg;
1963         int i, err;
1964
1965         if (!new->is_group) {
1966                 NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a nexthop.");
1967                 return -EINVAL;
1968         }
1969
1970         oldg = rtnl_dereference(old->nh_grp);
1971         newg = rtnl_dereference(new->nh_grp);
1972
1973         if (newg->hash_threshold != oldg->hash_threshold) {
1974                 NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with one of a different type.");
1975                 return -EINVAL;
1976         }
1977
1978         if (newg->hash_threshold) {
1979                 err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new,
1980                                              extack);
1981                 if (err)
1982                         return err;
1983         } else if (newg->resilient) {
1984                 new_res_table = rtnl_dereference(newg->res_table);
1985                 old_res_table = rtnl_dereference(oldg->res_table);
1986
1987                 /* Accept if num_nh_buckets was not given, but if it was
1988                  * given, demand that the value be correct.
1989                  */
1990                 if (cfg->nh_grp_res_has_num_buckets &&
1991                     cfg->nh_grp_res_num_buckets !=
1992                     old_res_table->num_nh_buckets) {
1993                         NL_SET_ERR_MSG(extack, "Can not change number of buckets of a resilient nexthop group.");
1994                         return -EINVAL;
1995                 }
1996
1997                 /* Emit a pre-replace notification so that listeners could veto
1998                  * a potentially unsupported configuration. Otherwise,
1999                  * individual bucket replacement notifications would need to be
2000                  * vetoed, which is something that should only happen if the
2001                  * bucket is currently active.
2002                  */
2003                 err = call_nexthop_res_table_notifiers(net, new, extack);
2004                 if (err)
2005                         return err;
2006
2007                 if (cfg->nh_grp_res_has_idle_timer)
2008                         old_res_table->idle_timer = cfg->nh_grp_res_idle_timer;
2009                 if (cfg->nh_grp_res_has_unbalanced_timer)
2010                         old_res_table->unbalanced_timer =
2011                                 cfg->nh_grp_res_unbalanced_timer;
2012
2013                 replace_nexthop_grp_res(oldg, newg);
2014
2015                 tmp_table = new_res_table;
2016                 rcu_assign_pointer(newg->res_table, old_res_table);
2017                 rcu_assign_pointer(newg->spare->res_table, old_res_table);
2018         }
2019
2020         /* update parents - used by nexthop code for cleanup */
2021         for (i = 0; i < newg->num_nh; i++)
2022                 newg->nh_entries[i].nh_parent = old;
2023
2024         rcu_assign_pointer(old->nh_grp, newg);
2025
2026         /* Make sure concurrent readers are not using 'oldg' anymore. */
2027         synchronize_net();
2028
2029         if (newg->resilient) {
2030                 rcu_assign_pointer(oldg->res_table, tmp_table);
2031                 rcu_assign_pointer(oldg->spare->res_table, tmp_table);
2032         }
2033
2034         for (i = 0; i < oldg->num_nh; i++)
2035                 oldg->nh_entries[i].nh_parent = new;
2036
2037         rcu_assign_pointer(new->nh_grp, oldg);
2038
2039         return 0;
2040 }
2041
2042 static void nh_group_v4_update(struct nh_group *nhg)
2043 {
2044         struct nh_grp_entry *nhges;
2045         bool has_v4 = false;
2046         int i;
2047
2048         nhges = nhg->nh_entries;
2049         for (i = 0; i < nhg->num_nh; i++) {
2050                 struct nh_info *nhi;
2051
2052                 nhi = rtnl_dereference(nhges[i].nh->nh_info);
2053                 if (nhi->family == AF_INET)
2054                         has_v4 = true;
2055         }
2056         nhg->has_v4 = has_v4;
2057 }
2058
2059 static int replace_nexthop_single_notify_res(struct net *net,
2060                                              struct nh_res_table *res_table,
2061                                              struct nexthop *old,
2062                                              struct nh_info *oldi,
2063                                              struct nh_info *newi,
2064                                              struct netlink_ext_ack *extack)
2065 {
2066         u32 nhg_id = res_table->nhg_id;
2067         int err;
2068         u16 i;
2069
2070         for (i = 0; i < res_table->num_nh_buckets; i++) {
2071                 struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
2072                 struct nh_grp_entry *nhge;
2073
2074                 nhge = rtnl_dereference(bucket->nh_entry);
2075                 if (nhge->nh == old) {
2076                         err = __call_nexthop_res_bucket_notifiers(net, nhg_id,
2077                                                                   i, true,
2078                                                                   oldi, newi,
2079                                                                   extack);
2080                         if (err)
2081                                 goto err_notify;
2082                 }
2083         }
2084
2085         return 0;
2086
2087 err_notify:
2088         while (i-- > 0) {
2089                 struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
2090                 struct nh_grp_entry *nhge;
2091
2092                 nhge = rtnl_dereference(bucket->nh_entry);
2093                 if (nhge->nh == old)
2094                         __call_nexthop_res_bucket_notifiers(net, nhg_id, i,
2095                                                             true, newi, oldi,
2096                                                             extack);
2097         }
2098         return err;
2099 }
2100
2101 static int replace_nexthop_single_notify(struct net *net,
2102                                          struct nexthop *group_nh,
2103                                          struct nexthop *old,
2104                                          struct nh_info *oldi,
2105                                          struct nh_info *newi,
2106                                          struct netlink_ext_ack *extack)
2107 {
2108         struct nh_group *nhg = rtnl_dereference(group_nh->nh_grp);
2109         struct nh_res_table *res_table;
2110
2111         if (nhg->hash_threshold) {
2112                 return call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE,
2113                                               group_nh, extack);
2114         } else if (nhg->resilient) {
2115                 res_table = rtnl_dereference(nhg->res_table);
2116                 return replace_nexthop_single_notify_res(net, res_table,
2117                                                          old, oldi, newi,
2118                                                          extack);
2119         }
2120
2121         return -EINVAL;
2122 }
2123
2124 static int replace_nexthop_single(struct net *net, struct nexthop *old,
2125                                   struct nexthop *new,
2126                                   struct netlink_ext_ack *extack)
2127 {
2128         u8 old_protocol, old_nh_flags;
2129         struct nh_info *oldi, *newi;
2130         struct nh_grp_entry *nhge;
2131         int err;
2132
2133         if (new->is_group) {
2134                 NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a nexthop group.");
2135                 return -EINVAL;
2136         }
2137
2138         err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new, extack);
2139         if (err)
2140                 return err;
2141
2142         /* Hardware flags were set on 'old' as 'new' is not in the red-black
2143          * tree. Therefore, inherit the flags from 'old' to 'new'.
2144          */
2145         new->nh_flags |= old->nh_flags & (RTNH_F_OFFLOAD | RTNH_F_TRAP);
2146
2147         oldi = rtnl_dereference(old->nh_info);
2148         newi = rtnl_dereference(new->nh_info);
2149
2150         newi->nh_parent = old;
2151         oldi->nh_parent = new;
2152
2153         old_protocol = old->protocol;
2154         old_nh_flags = old->nh_flags;
2155
2156         old->protocol = new->protocol;
2157         old->nh_flags = new->nh_flags;
2158
2159         rcu_assign_pointer(old->nh_info, newi);
2160         rcu_assign_pointer(new->nh_info, oldi);
2161
2162         /* Send a replace notification for all the groups using the nexthop. */
2163         list_for_each_entry(nhge, &old->grp_list, nh_list) {
2164                 struct nexthop *nhp = nhge->nh_parent;
2165
2166                 err = replace_nexthop_single_notify(net, nhp, old, oldi, newi,
2167                                                     extack);
2168                 if (err)
2169                         goto err_notify;
2170         }
2171
2172         /* When replacing an IPv4 nexthop with an IPv6 nexthop, potentially
2173          * update IPv4 indication in all the groups using the nexthop.
2174          */
2175         if (oldi->family == AF_INET && newi->family == AF_INET6) {
2176                 list_for_each_entry(nhge, &old->grp_list, nh_list) {
2177                         struct nexthop *nhp = nhge->nh_parent;
2178                         struct nh_group *nhg;
2179
2180                         nhg = rtnl_dereference(nhp->nh_grp);
2181                         nh_group_v4_update(nhg);
2182                 }
2183         }
2184
2185         return 0;
2186
2187 err_notify:
2188         rcu_assign_pointer(new->nh_info, newi);
2189         rcu_assign_pointer(old->nh_info, oldi);
2190         old->nh_flags = old_nh_flags;
2191         old->protocol = old_protocol;
2192         oldi->nh_parent = old;
2193         newi->nh_parent = new;
2194         list_for_each_entry_continue_reverse(nhge, &old->grp_list, nh_list) {
2195                 struct nexthop *nhp = nhge->nh_parent;
2196
2197                 replace_nexthop_single_notify(net, nhp, old, newi, oldi, NULL);
2198         }
2199         call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, old, extack);
2200         return err;
2201 }
2202
2203 static void __nexthop_replace_notify(struct net *net, struct nexthop *nh,
2204                                      struct nl_info *info)
2205 {
2206         struct fib6_info *f6i;
2207
2208         if (!list_empty(&nh->fi_list)) {
2209                 struct fib_info *fi;
2210
2211                 /* expectation is a few fib_info per nexthop and then
2212                  * a lot of routes per fib_info. So mark the fib_info
2213                  * and then walk the fib tables once
2214                  */
2215                 list_for_each_entry(fi, &nh->fi_list, nh_list)
2216                         fi->nh_updated = true;
2217
2218                 fib_info_notify_update(net, info);
2219
2220                 list_for_each_entry(fi, &nh->fi_list, nh_list)
2221                         fi->nh_updated = false;
2222         }
2223
2224         list_for_each_entry(f6i, &nh->f6i_list, nh_list)
2225                 ipv6_stub->fib6_rt_update(net, f6i, info);
2226 }
2227
2228 /* send RTM_NEWROUTE with REPLACE flag set for all FIB entries
2229  * linked to this nexthop and for all groups that the nexthop
2230  * is a member of
2231  */
2232 static void nexthop_replace_notify(struct net *net, struct nexthop *nh,
2233                                    struct nl_info *info)
2234 {
2235         struct nh_grp_entry *nhge;
2236
2237         __nexthop_replace_notify(net, nh, info);
2238
2239         list_for_each_entry(nhge, &nh->grp_list, nh_list)
2240                 __nexthop_replace_notify(net, nhge->nh_parent, info);
2241 }
2242
2243 static int replace_nexthop(struct net *net, struct nexthop *old,
2244                            struct nexthop *new, const struct nh_config *cfg,
2245                            struct netlink_ext_ack *extack)
2246 {
2247         bool new_is_reject = false;
2248         struct nh_grp_entry *nhge;
2249         int err;
2250
2251         /* check that existing FIB entries are ok with the
2252          * new nexthop definition
2253          */
2254         err = fib_check_nh_list(old, new, extack);
2255         if (err)
2256                 return err;
2257
2258         err = fib6_check_nh_list(old, new, extack);
2259         if (err)
2260                 return err;
2261
2262         if (!new->is_group) {
2263                 struct nh_info *nhi = rtnl_dereference(new->nh_info);
2264
2265                 new_is_reject = nhi->reject_nh;
2266         }
2267
2268         list_for_each_entry(nhge, &old->grp_list, nh_list) {
2269                 /* if new nexthop is a blackhole, any groups using this
2270                  * nexthop cannot have more than 1 path
2271                  */
2272                 if (new_is_reject &&
2273                     nexthop_num_path(nhge->nh_parent) > 1) {
2274                         NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a member of a group with more than one path");
2275                         return -EINVAL;
2276                 }
2277
2278                 err = fib_check_nh_list(nhge->nh_parent, new, extack);
2279                 if (err)
2280                         return err;
2281
2282                 err = fib6_check_nh_list(nhge->nh_parent, new, extack);
2283                 if (err)
2284                         return err;
2285         }
2286
2287         if (old->is_group)
2288                 err = replace_nexthop_grp(net, old, new, cfg, extack);
2289         else
2290                 err = replace_nexthop_single(net, old, new, extack);
2291
2292         if (!err) {
2293                 nh_rt_cache_flush(net, old, new);
2294
2295                 __remove_nexthop(net, new, NULL);
2296                 nexthop_put(new);
2297         }
2298
2299         return err;
2300 }
2301
2302 /* called with rtnl_lock held */
2303 static int insert_nexthop(struct net *net, struct nexthop *new_nh,
2304                           struct nh_config *cfg, struct netlink_ext_ack *extack)
2305 {
2306         struct rb_node **pp, *parent = NULL, *next;
2307         struct rb_root *root = &net->nexthop.rb_root;
2308         bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
2309         bool create = !!(cfg->nlflags & NLM_F_CREATE);
2310         u32 new_id = new_nh->id;
2311         int replace_notify = 0;
2312         int rc = -EEXIST;
2313
2314         pp = &root->rb_node;
2315         while (1) {
2316                 struct nexthop *nh;
2317
2318                 next = *pp;
2319                 if (!next)
2320                         break;
2321
2322                 parent = next;
2323
2324                 nh = rb_entry(parent, struct nexthop, rb_node);
2325                 if (new_id < nh->id) {
2326                         pp = &next->rb_left;
2327                 } else if (new_id > nh->id) {
2328                         pp = &next->rb_right;
2329                 } else if (replace) {
2330                         rc = replace_nexthop(net, nh, new_nh, cfg, extack);
2331                         if (!rc) {
2332                                 new_nh = nh; /* send notification with old nh */
2333                                 replace_notify = 1;
2334                         }
2335                         goto out;
2336                 } else {
2337                         /* id already exists and not a replace */
2338                         goto out;
2339                 }
2340         }
2341
2342         if (replace && !create) {
2343                 NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists");
2344                 rc = -ENOENT;
2345                 goto out;
2346         }
2347
2348         if (new_nh->is_group) {
2349                 struct nh_group *nhg = rtnl_dereference(new_nh->nh_grp);
2350                 struct nh_res_table *res_table;
2351
2352                 if (nhg->resilient) {
2353                         res_table = rtnl_dereference(nhg->res_table);
2354
2355                         /* Not passing the number of buckets is OK when
2356                          * replacing, but not when creating a new group.
2357                          */
2358                         if (!cfg->nh_grp_res_has_num_buckets) {
2359                                 NL_SET_ERR_MSG(extack, "Number of buckets not specified for nexthop group insertion");
2360                                 rc = -EINVAL;
2361                                 goto out;
2362                         }
2363
2364                         nh_res_group_rebalance(nhg, res_table);
2365
2366                         /* Do not send bucket notifications, we do full
2367                          * notification below.
2368                          */
2369                         nh_res_table_upkeep(res_table, false, false);
2370                 }
2371         }
2372
2373         rb_link_node_rcu(&new_nh->rb_node, parent, pp);
2374         rb_insert_color(&new_nh->rb_node, root);
2375
2376         /* The initial insertion is a full notification for hash-threshold as
2377          * well as resilient groups.
2378          */
2379         rc = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new_nh, extack);
2380         if (rc)
2381                 rb_erase(&new_nh->rb_node, &net->nexthop.rb_root);
2382
2383 out:
2384         if (!rc) {
2385                 nh_base_seq_inc(net);
2386                 nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
2387                 if (replace_notify &&
2388                     READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode))
2389                         nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
2390         }
2391
2392         return rc;
2393 }
2394
2395 /* rtnl */
2396 /* remove all nexthops tied to a device being deleted */
2397 static void nexthop_flush_dev(struct net_device *dev, unsigned long event)
2398 {
2399         unsigned int hash = nh_dev_hashfn(dev->ifindex);
2400         struct net *net = dev_net(dev);
2401         struct hlist_head *head = &net->nexthop.devhash[hash];
2402         struct hlist_node *n;
2403         struct nh_info *nhi;
2404
2405         hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
2406                 if (nhi->fib_nhc.nhc_dev != dev)
2407                         continue;
2408
2409                 if (nhi->reject_nh &&
2410                     (event == NETDEV_DOWN || event == NETDEV_CHANGE))
2411                         continue;
2412
2413                 remove_nexthop(net, nhi->nh_parent, NULL);
2414         }
2415 }
2416
2417 /* rtnl; called when net namespace is deleted */
2418 static void flush_all_nexthops(struct net *net)
2419 {
2420         struct rb_root *root = &net->nexthop.rb_root;
2421         struct rb_node *node;
2422         struct nexthop *nh;
2423
2424         while ((node = rb_first(root))) {
2425                 nh = rb_entry(node, struct nexthop, rb_node);
2426                 remove_nexthop(net, nh, NULL);
2427                 cond_resched();
2428         }
2429 }
2430
2431 static struct nexthop *nexthop_create_group(struct net *net,
2432                                             struct nh_config *cfg)
2433 {
2434         struct nlattr *grps_attr = cfg->nh_grp;
2435         struct nexthop_grp *entry = nla_data(grps_attr);
2436         u16 num_nh = nla_len(grps_attr) / sizeof(*entry);
2437         struct nh_group *nhg;
2438         struct nexthop *nh;
2439         int err;
2440         int i;
2441
2442         if (WARN_ON(!num_nh))
2443                 return ERR_PTR(-EINVAL);
2444
2445         nh = nexthop_alloc();
2446         if (!nh)
2447                 return ERR_PTR(-ENOMEM);
2448
2449         nh->is_group = 1;
2450
2451         nhg = nexthop_grp_alloc(num_nh);
2452         if (!nhg) {
2453                 kfree(nh);
2454                 return ERR_PTR(-ENOMEM);
2455         }
2456
2457         /* spare group used for removals */
2458         nhg->spare = nexthop_grp_alloc(num_nh);
2459         if (!nhg->spare) {
2460                 kfree(nhg);
2461                 kfree(nh);
2462                 return ERR_PTR(-ENOMEM);
2463         }
2464         nhg->spare->spare = nhg;
2465
2466         for (i = 0; i < nhg->num_nh; ++i) {
2467                 struct nexthop *nhe;
2468                 struct nh_info *nhi;
2469
2470                 nhe = nexthop_find_by_id(net, entry[i].id);
2471                 if (!nexthop_get(nhe)) {
2472                         err = -ENOENT;
2473                         goto out_no_nh;
2474                 }
2475
2476                 nhi = rtnl_dereference(nhe->nh_info);
2477                 if (nhi->family == AF_INET)
2478                         nhg->has_v4 = true;
2479
2480                 nhg->nh_entries[i].nh = nhe;
2481                 nhg->nh_entries[i].weight = entry[i].weight + 1;
2482                 list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list);
2483                 nhg->nh_entries[i].nh_parent = nh;
2484         }
2485
2486         if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) {
2487                 nhg->hash_threshold = 1;
2488                 nhg->is_multipath = true;
2489         } else if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES) {
2490                 struct nh_res_table *res_table;
2491
2492                 res_table = nexthop_res_table_alloc(net, cfg->nh_id, cfg);
2493                 if (!res_table) {
2494                         err = -ENOMEM;
2495                         goto out_no_nh;
2496                 }
2497
2498                 rcu_assign_pointer(nhg->spare->res_table, res_table);
2499                 rcu_assign_pointer(nhg->res_table, res_table);
2500                 nhg->resilient = true;
2501                 nhg->is_multipath = true;
2502         }
2503
2504         WARN_ON_ONCE(nhg->hash_threshold + nhg->resilient != 1);
2505
2506         if (nhg->hash_threshold)
2507                 nh_hthr_group_rebalance(nhg);
2508
2509         if (cfg->nh_fdb)
2510                 nhg->fdb_nh = 1;
2511
2512         rcu_assign_pointer(nh->nh_grp, nhg);
2513
2514         return nh;
2515
2516 out_no_nh:
2517         for (i--; i >= 0; --i) {
2518                 list_del(&nhg->nh_entries[i].nh_list);
2519                 nexthop_put(nhg->nh_entries[i].nh);
2520         }
2521
2522         kfree(nhg->spare);
2523         kfree(nhg);
2524         kfree(nh);
2525
2526         return ERR_PTR(err);
2527 }
2528
2529 static int nh_create_ipv4(struct net *net, struct nexthop *nh,
2530                           struct nh_info *nhi, struct nh_config *cfg,
2531                           struct netlink_ext_ack *extack)
2532 {
2533         struct fib_nh *fib_nh = &nhi->fib_nh;
2534         struct fib_config fib_cfg = {
2535                 .fc_oif   = cfg->nh_ifindex,
2536                 .fc_gw4   = cfg->gw.ipv4,
2537                 .fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0,
2538                 .fc_flags = cfg->nh_flags,
2539                 .fc_nlinfo = cfg->nlinfo,
2540                 .fc_encap = cfg->nh_encap,
2541                 .fc_encap_type = cfg->nh_encap_type,
2542         };
2543         u32 tb_id = (cfg->dev ? l3mdev_fib_table(cfg->dev) : RT_TABLE_MAIN);
2544         int err;
2545
2546         err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack);
2547         if (err) {
2548                 fib_nh_release(net, fib_nh);
2549                 goto out;
2550         }
2551
2552         if (nhi->fdb_nh)
2553                 goto out;
2554
2555         /* sets nh_dev if successful */
2556         err = fib_check_nh(net, fib_nh, tb_id, 0, extack);
2557         if (!err) {
2558                 nh->nh_flags = fib_nh->fib_nh_flags;
2559                 fib_info_update_nhc_saddr(net, &fib_nh->nh_common,
2560                                           !fib_nh->fib_nh_scope ? 0 : fib_nh->fib_nh_scope - 1);
2561         } else {
2562                 fib_nh_release(net, fib_nh);
2563         }
2564 out:
2565         return err;
2566 }
2567
2568 static int nh_create_ipv6(struct net *net,  struct nexthop *nh,
2569                           struct nh_info *nhi, struct nh_config *cfg,
2570                           struct netlink_ext_ack *extack)
2571 {
2572         struct fib6_nh *fib6_nh = &nhi->fib6_nh;
2573         struct fib6_config fib6_cfg = {
2574                 .fc_table = l3mdev_fib_table(cfg->dev),
2575                 .fc_ifindex = cfg->nh_ifindex,
2576                 .fc_gateway = cfg->gw.ipv6,
2577                 .fc_flags = cfg->nh_flags,
2578                 .fc_nlinfo = cfg->nlinfo,
2579                 .fc_encap = cfg->nh_encap,
2580                 .fc_encap_type = cfg->nh_encap_type,
2581                 .fc_is_fdb = cfg->nh_fdb,
2582         };
2583         int err;
2584
2585         if (!ipv6_addr_any(&cfg->gw.ipv6))
2586                 fib6_cfg.fc_flags |= RTF_GATEWAY;
2587
2588         /* sets nh_dev if successful */
2589         err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL,
2590                                       extack);
2591         if (err) {
2592                 /* IPv6 is not enabled, don't call fib6_nh_release */
2593                 if (err == -EAFNOSUPPORT)
2594                         goto out;
2595                 ipv6_stub->fib6_nh_release(fib6_nh);
2596         } else {
2597                 nh->nh_flags = fib6_nh->fib_nh_flags;
2598         }
2599 out:
2600         return err;
2601 }
2602
2603 static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg,
2604                                       struct netlink_ext_ack *extack)
2605 {
2606         struct nh_info *nhi;
2607         struct nexthop *nh;
2608         int err = 0;
2609
2610         nh = nexthop_alloc();
2611         if (!nh)
2612                 return ERR_PTR(-ENOMEM);
2613
2614         nhi = kzalloc(sizeof(*nhi), GFP_KERNEL);
2615         if (!nhi) {
2616                 kfree(nh);
2617                 return ERR_PTR(-ENOMEM);
2618         }
2619
2620         nh->nh_flags = cfg->nh_flags;
2621         nh->net = net;
2622
2623         nhi->nh_parent = nh;
2624         nhi->family = cfg->nh_family;
2625         nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK;
2626
2627         if (cfg->nh_fdb)
2628                 nhi->fdb_nh = 1;
2629
2630         if (cfg->nh_blackhole) {
2631                 nhi->reject_nh = 1;
2632                 cfg->nh_ifindex = net->loopback_dev->ifindex;
2633         }
2634
2635         switch (cfg->nh_family) {
2636         case AF_INET:
2637                 err = nh_create_ipv4(net, nh, nhi, cfg, extack);
2638                 break;
2639         case AF_INET6:
2640                 err = nh_create_ipv6(net, nh, nhi, cfg, extack);
2641                 break;
2642         }
2643
2644         if (err) {
2645                 kfree(nhi);
2646                 kfree(nh);
2647                 return ERR_PTR(err);
2648         }
2649
2650         /* add the entry to the device based hash */
2651         if (!nhi->fdb_nh)
2652                 nexthop_devhash_add(net, nhi);
2653
2654         rcu_assign_pointer(nh->nh_info, nhi);
2655
2656         return nh;
2657 }
2658
2659 /* called with rtnl lock held */
2660 static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
2661                                    struct netlink_ext_ack *extack)
2662 {
2663         struct nexthop *nh;
2664         int err;
2665
2666         if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
2667                 NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
2668                 return ERR_PTR(-EINVAL);
2669         }
2670
2671         if (!cfg->nh_id) {
2672                 cfg->nh_id = nh_find_unused_id(net);
2673                 if (!cfg->nh_id) {
2674                         NL_SET_ERR_MSG(extack, "No unused id");
2675                         return ERR_PTR(-EINVAL);
2676                 }
2677         }
2678
2679         if (cfg->nh_grp)
2680                 nh = nexthop_create_group(net, cfg);
2681         else
2682                 nh = nexthop_create(net, cfg, extack);
2683
2684         if (IS_ERR(nh))
2685                 return nh;
2686
2687         refcount_set(&nh->refcnt, 1);
2688         nh->id = cfg->nh_id;
2689         nh->protocol = cfg->nh_protocol;
2690         nh->net = net;
2691
2692         err = insert_nexthop(net, nh, cfg, extack);
2693         if (err) {
2694                 __remove_nexthop(net, nh, NULL);
2695                 nexthop_put(nh);
2696                 nh = ERR_PTR(err);
2697         }
2698
2699         return nh;
2700 }
2701
2702 static int rtm_nh_get_timer(struct nlattr *attr, unsigned long fallback,
2703                             unsigned long *timer_p, bool *has_p,
2704                             struct netlink_ext_ack *extack)
2705 {
2706         unsigned long timer;
2707         u32 value;
2708
2709         if (!attr) {
2710                 *timer_p = fallback;
2711                 *has_p = false;
2712                 return 0;
2713         }
2714
2715         value = nla_get_u32(attr);
2716         timer = clock_t_to_jiffies(value);
2717         if (timer == ~0UL) {
2718                 NL_SET_ERR_MSG(extack, "Timer value too large");
2719                 return -EINVAL;
2720         }
2721
2722         *timer_p = timer;
2723         *has_p = true;
2724         return 0;
2725 }
2726
2727 static int rtm_to_nh_config_grp_res(struct nlattr *res, struct nh_config *cfg,
2728                                     struct netlink_ext_ack *extack)
2729 {
2730         struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_policy_new)] = {};
2731         int err;
2732
2733         if (res) {
2734                 err = nla_parse_nested(tb,
2735                                        ARRAY_SIZE(rtm_nh_res_policy_new) - 1,
2736                                        res, rtm_nh_res_policy_new, extack);
2737                 if (err < 0)
2738                         return err;
2739         }
2740
2741         if (tb[NHA_RES_GROUP_BUCKETS]) {
2742                 cfg->nh_grp_res_num_buckets =
2743                         nla_get_u16(tb[NHA_RES_GROUP_BUCKETS]);
2744                 cfg->nh_grp_res_has_num_buckets = true;
2745                 if (!cfg->nh_grp_res_num_buckets) {
2746                         NL_SET_ERR_MSG(extack, "Number of buckets needs to be non-0");
2747                         return -EINVAL;
2748                 }
2749         }
2750
2751         err = rtm_nh_get_timer(tb[NHA_RES_GROUP_IDLE_TIMER],
2752                                NH_RES_DEFAULT_IDLE_TIMER,
2753                                &cfg->nh_grp_res_idle_timer,
2754                                &cfg->nh_grp_res_has_idle_timer,
2755                                extack);
2756         if (err)
2757                 return err;
2758
2759         return rtm_nh_get_timer(tb[NHA_RES_GROUP_UNBALANCED_TIMER],
2760                                 NH_RES_DEFAULT_UNBALANCED_TIMER,
2761                                 &cfg->nh_grp_res_unbalanced_timer,
2762                                 &cfg->nh_grp_res_has_unbalanced_timer,
2763                                 extack);
2764 }
2765
2766 static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
2767                             struct nlmsghdr *nlh, struct nh_config *cfg,
2768                             struct netlink_ext_ack *extack)
2769 {
2770         struct nhmsg *nhm = nlmsg_data(nlh);
2771         struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_new)];
2772         int err;
2773
2774         err = nlmsg_parse(nlh, sizeof(*nhm), tb,
2775                           ARRAY_SIZE(rtm_nh_policy_new) - 1,
2776                           rtm_nh_policy_new, extack);
2777         if (err < 0)
2778                 return err;
2779
2780         err = -EINVAL;
2781         if (nhm->resvd || nhm->nh_scope) {
2782                 NL_SET_ERR_MSG(extack, "Invalid values in ancillary header");
2783                 goto out;
2784         }
2785         if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
2786                 NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
2787                 goto out;
2788         }
2789
2790         switch (nhm->nh_family) {
2791         case AF_INET:
2792         case AF_INET6:
2793                 break;
2794         case AF_UNSPEC:
2795                 if (tb[NHA_GROUP])
2796                         break;
2797                 fallthrough;
2798         default:
2799                 NL_SET_ERR_MSG(extack, "Invalid address family");
2800                 goto out;
2801         }
2802
2803         memset(cfg, 0, sizeof(*cfg));
2804         cfg->nlflags = nlh->nlmsg_flags;
2805         cfg->nlinfo.portid = NETLINK_CB(skb).portid;
2806         cfg->nlinfo.nlh = nlh;
2807         cfg->nlinfo.nl_net = net;
2808
2809         cfg->nh_family = nhm->nh_family;
2810         cfg->nh_protocol = nhm->nh_protocol;
2811         cfg->nh_flags = nhm->nh_flags;
2812
2813         if (tb[NHA_ID])
2814                 cfg->nh_id = nla_get_u32(tb[NHA_ID]);
2815
2816         if (tb[NHA_FDB]) {
2817                 if (tb[NHA_OIF] || tb[NHA_BLACKHOLE] ||
2818                     tb[NHA_ENCAP]   || tb[NHA_ENCAP_TYPE]) {
2819                         NL_SET_ERR_MSG(extack, "Fdb attribute can not be used with encap, oif or blackhole");
2820                         goto out;
2821                 }
2822                 if (nhm->nh_flags) {
2823                         NL_SET_ERR_MSG(extack, "Unsupported nexthop flags in ancillary header");
2824                         goto out;
2825                 }
2826                 cfg->nh_fdb = nla_get_flag(tb[NHA_FDB]);
2827         }
2828
2829         if (tb[NHA_GROUP]) {
2830                 if (nhm->nh_family != AF_UNSPEC) {
2831                         NL_SET_ERR_MSG(extack, "Invalid family for group");
2832                         goto out;
2833                 }
2834                 cfg->nh_grp = tb[NHA_GROUP];
2835
2836                 cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH;
2837                 if (tb[NHA_GROUP_TYPE])
2838                         cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]);
2839
2840                 if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) {
2841                         NL_SET_ERR_MSG(extack, "Invalid group type");
2842                         goto out;
2843                 }
2844                 err = nh_check_attr_group(net, tb, ARRAY_SIZE(tb),
2845                                           cfg->nh_grp_type, extack);
2846                 if (err)
2847                         goto out;
2848
2849                 if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES)
2850                         err = rtm_to_nh_config_grp_res(tb[NHA_RES_GROUP],
2851                                                        cfg, extack);
2852
2853                 /* no other attributes should be set */
2854                 goto out;
2855         }
2856
2857         if (tb[NHA_BLACKHOLE]) {
2858                 if (tb[NHA_GATEWAY] || tb[NHA_OIF] ||
2859                     tb[NHA_ENCAP]   || tb[NHA_ENCAP_TYPE] || tb[NHA_FDB]) {
2860                         NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway, oif, encap or fdb");
2861                         goto out;
2862                 }
2863
2864                 cfg->nh_blackhole = 1;
2865                 err = 0;
2866                 goto out;
2867         }
2868
2869         if (!cfg->nh_fdb && !tb[NHA_OIF]) {
2870                 NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole and non-fdb nexthops");
2871                 goto out;
2872         }
2873
2874         if (!cfg->nh_fdb && tb[NHA_OIF]) {
2875                 cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]);
2876                 if (cfg->nh_ifindex)
2877                         cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex);
2878
2879                 if (!cfg->dev) {
2880                         NL_SET_ERR_MSG(extack, "Invalid device index");
2881                         goto out;
2882                 } else if (!(cfg->dev->flags & IFF_UP)) {
2883                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
2884                         err = -ENETDOWN;
2885                         goto out;
2886                 } else if (!netif_carrier_ok(cfg->dev)) {
2887                         NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down");
2888                         err = -ENETDOWN;
2889                         goto out;
2890                 }
2891         }
2892
2893         err = -EINVAL;
2894         if (tb[NHA_GATEWAY]) {
2895                 struct nlattr *gwa = tb[NHA_GATEWAY];
2896
2897                 switch (cfg->nh_family) {
2898                 case AF_INET:
2899                         if (nla_len(gwa) != sizeof(u32)) {
2900                                 NL_SET_ERR_MSG(extack, "Invalid gateway");
2901                                 goto out;
2902                         }
2903                         cfg->gw.ipv4 = nla_get_be32(gwa);
2904                         break;
2905                 case AF_INET6:
2906                         if (nla_len(gwa) != sizeof(struct in6_addr)) {
2907                                 NL_SET_ERR_MSG(extack, "Invalid gateway");
2908                                 goto out;
2909                         }
2910                         cfg->gw.ipv6 = nla_get_in6_addr(gwa);
2911                         break;
2912                 default:
2913                         NL_SET_ERR_MSG(extack,
2914                                        "Unknown address family for gateway");
2915                         goto out;
2916                 }
2917         } else {
2918                 /* device only nexthop (no gateway) */
2919                 if (cfg->nh_flags & RTNH_F_ONLINK) {
2920                         NL_SET_ERR_MSG(extack,
2921                                        "ONLINK flag can not be set for nexthop without a gateway");
2922                         goto out;
2923                 }
2924         }
2925
2926         if (tb[NHA_ENCAP]) {
2927                 cfg->nh_encap = tb[NHA_ENCAP];
2928
2929                 if (!tb[NHA_ENCAP_TYPE]) {
2930                         NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing");
2931                         goto out;
2932                 }
2933
2934                 cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]);
2935                 err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack);
2936                 if (err < 0)
2937                         goto out;
2938
2939         } else if (tb[NHA_ENCAP_TYPE]) {
2940                 NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing");
2941                 goto out;
2942         }
2943
2944
2945         err = 0;
2946 out:
2947         return err;
2948 }
2949
2950 /* rtnl */
2951 static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
2952                            struct netlink_ext_ack *extack)
2953 {
2954         struct net *net = sock_net(skb->sk);
2955         struct nh_config cfg;
2956         struct nexthop *nh;
2957         int err;
2958
2959         err = rtm_to_nh_config(net, skb, nlh, &cfg, extack);
2960         if (!err) {
2961                 nh = nexthop_add(net, &cfg, extack);
2962                 if (IS_ERR(nh))
2963                         err = PTR_ERR(nh);
2964         }
2965
2966         return err;
2967 }
2968
2969 static int __nh_valid_get_del_req(const struct nlmsghdr *nlh,
2970                                   struct nlattr **tb, u32 *id,
2971                                   struct netlink_ext_ack *extack)
2972 {
2973         struct nhmsg *nhm = nlmsg_data(nlh);
2974
2975         if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
2976                 NL_SET_ERR_MSG(extack, "Invalid values in header");
2977                 return -EINVAL;
2978         }
2979
2980         if (!tb[NHA_ID]) {
2981                 NL_SET_ERR_MSG(extack, "Nexthop id is missing");
2982                 return -EINVAL;
2983         }
2984
2985         *id = nla_get_u32(tb[NHA_ID]);
2986         if (!(*id)) {
2987                 NL_SET_ERR_MSG(extack, "Invalid nexthop id");
2988                 return -EINVAL;
2989         }
2990
2991         return 0;
2992 }
2993
2994 static int nh_valid_get_del_req(const struct nlmsghdr *nlh, u32 *id,
2995                                 struct netlink_ext_ack *extack)
2996 {
2997         struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get)];
2998         int err;
2999
3000         err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3001                           ARRAY_SIZE(rtm_nh_policy_get) - 1,
3002                           rtm_nh_policy_get, extack);
3003         if (err < 0)
3004                 return err;
3005
3006         return __nh_valid_get_del_req(nlh, tb, id, extack);
3007 }
3008
3009 /* rtnl */
3010 static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
3011                            struct netlink_ext_ack *extack)
3012 {
3013         struct net *net = sock_net(skb->sk);
3014         struct nl_info nlinfo = {
3015                 .nlh = nlh,
3016                 .nl_net = net,
3017                 .portid = NETLINK_CB(skb).portid,
3018         };
3019         struct nexthop *nh;
3020         int err;
3021         u32 id;
3022
3023         err = nh_valid_get_del_req(nlh, &id, extack);
3024         if (err)
3025                 return err;
3026
3027         nh = nexthop_find_by_id(net, id);
3028         if (!nh)
3029                 return -ENOENT;
3030
3031         remove_nexthop(net, nh, &nlinfo);
3032
3033         return 0;
3034 }
3035
3036 /* rtnl */
3037 static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3038                            struct netlink_ext_ack *extack)
3039 {
3040         struct net *net = sock_net(in_skb->sk);
3041         struct sk_buff *skb = NULL;
3042         struct nexthop *nh;
3043         int err;
3044         u32 id;
3045
3046         err = nh_valid_get_del_req(nlh, &id, extack);
3047         if (err)
3048                 return err;
3049
3050         err = -ENOBUFS;
3051         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3052         if (!skb)
3053                 goto out;
3054
3055         err = -ENOENT;
3056         nh = nexthop_find_by_id(net, id);
3057         if (!nh)
3058                 goto errout_free;
3059
3060         err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid,
3061                            nlh->nlmsg_seq, 0);
3062         if (err < 0) {
3063                 WARN_ON(err == -EMSGSIZE);
3064                 goto errout_free;
3065         }
3066
3067         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3068 out:
3069         return err;
3070 errout_free:
3071         kfree_skb(skb);
3072         goto out;
3073 }
3074
3075 struct nh_dump_filter {
3076         u32 nh_id;
3077         int dev_idx;
3078         int master_idx;
3079         bool group_filter;
3080         bool fdb_filter;
3081         u32 res_bucket_nh_id;
3082 };
3083
3084 static bool nh_dump_filtered(struct nexthop *nh,
3085                              struct nh_dump_filter *filter, u8 family)
3086 {
3087         const struct net_device *dev;
3088         const struct nh_info *nhi;
3089
3090         if (filter->group_filter && !nh->is_group)
3091                 return true;
3092
3093         if (!filter->dev_idx && !filter->master_idx && !family)
3094                 return false;
3095
3096         if (nh->is_group)
3097                 return true;
3098
3099         nhi = rtnl_dereference(nh->nh_info);
3100         if (family && nhi->family != family)
3101                 return true;
3102
3103         dev = nhi->fib_nhc.nhc_dev;
3104         if (filter->dev_idx && (!dev || dev->ifindex != filter->dev_idx))
3105                 return true;
3106
3107         if (filter->master_idx) {
3108                 struct net_device *master;
3109
3110                 if (!dev)
3111                         return true;
3112
3113                 master = netdev_master_upper_dev_get((struct net_device *)dev);
3114                 if (!master || master->ifindex != filter->master_idx)
3115                         return true;
3116         }
3117
3118         return false;
3119 }
3120
3121 static int __nh_valid_dump_req(const struct nlmsghdr *nlh, struct nlattr **tb,
3122                                struct nh_dump_filter *filter,
3123                                struct netlink_ext_ack *extack)
3124 {
3125         struct nhmsg *nhm;
3126         u32 idx;
3127
3128         if (tb[NHA_OIF]) {
3129                 idx = nla_get_u32(tb[NHA_OIF]);
3130                 if (idx > INT_MAX) {
3131                         NL_SET_ERR_MSG(extack, "Invalid device index");
3132                         return -EINVAL;
3133                 }
3134                 filter->dev_idx = idx;
3135         }
3136         if (tb[NHA_MASTER]) {
3137                 idx = nla_get_u32(tb[NHA_MASTER]);
3138                 if (idx > INT_MAX) {
3139                         NL_SET_ERR_MSG(extack, "Invalid master device index");
3140                         return -EINVAL;
3141                 }
3142                 filter->master_idx = idx;
3143         }
3144         filter->group_filter = nla_get_flag(tb[NHA_GROUPS]);
3145         filter->fdb_filter = nla_get_flag(tb[NHA_FDB]);
3146
3147         nhm = nlmsg_data(nlh);
3148         if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
3149                 NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request");
3150                 return -EINVAL;
3151         }
3152
3153         return 0;
3154 }
3155
3156 static int nh_valid_dump_req(const struct nlmsghdr *nlh,
3157                              struct nh_dump_filter *filter,
3158                              struct netlink_callback *cb)
3159 {
3160         struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump)];
3161         int err;
3162
3163         err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3164                           ARRAY_SIZE(rtm_nh_policy_dump) - 1,
3165                           rtm_nh_policy_dump, cb->extack);
3166         if (err < 0)
3167                 return err;
3168
3169         return __nh_valid_dump_req(nlh, tb, filter, cb->extack);
3170 }
3171
3172 struct rtm_dump_nh_ctx {
3173         u32 idx;
3174 };
3175
3176 static struct rtm_dump_nh_ctx *
3177 rtm_dump_nh_ctx(struct netlink_callback *cb)
3178 {
3179         struct rtm_dump_nh_ctx *ctx = (void *)cb->ctx;
3180
3181         BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
3182         return ctx;
3183 }
3184
3185 static int rtm_dump_walk_nexthops(struct sk_buff *skb,
3186                                   struct netlink_callback *cb,
3187                                   struct rb_root *root,
3188                                   struct rtm_dump_nh_ctx *ctx,
3189                                   int (*nh_cb)(struct sk_buff *skb,
3190                                                struct netlink_callback *cb,
3191                                                struct nexthop *nh, void *data),
3192                                   void *data)
3193 {
3194         struct rb_node *node;
3195         int s_idx;
3196         int err;
3197
3198         s_idx = ctx->idx;
3199         for (node = rb_first(root); node; node = rb_next(node)) {
3200                 struct nexthop *nh;
3201
3202                 nh = rb_entry(node, struct nexthop, rb_node);
3203                 if (nh->id < s_idx)
3204                         continue;
3205
3206                 ctx->idx = nh->id;
3207                 err = nh_cb(skb, cb, nh, data);
3208                 if (err)
3209                         return err;
3210         }
3211
3212         return 0;
3213 }
3214
3215 static int rtm_dump_nexthop_cb(struct sk_buff *skb, struct netlink_callback *cb,
3216                                struct nexthop *nh, void *data)
3217 {
3218         struct nhmsg *nhm = nlmsg_data(cb->nlh);
3219         struct nh_dump_filter *filter = data;
3220
3221         if (nh_dump_filtered(nh, filter, nhm->nh_family))
3222                 return 0;
3223
3224         return nh_fill_node(skb, nh, RTM_NEWNEXTHOP,
3225                             NETLINK_CB(cb->skb).portid,
3226                             cb->nlh->nlmsg_seq, NLM_F_MULTI);
3227 }
3228
3229 /* rtnl */
3230 static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
3231 {
3232         struct rtm_dump_nh_ctx *ctx = rtm_dump_nh_ctx(cb);
3233         struct net *net = sock_net(skb->sk);
3234         struct rb_root *root = &net->nexthop.rb_root;
3235         struct nh_dump_filter filter = {};
3236         int err;
3237
3238         err = nh_valid_dump_req(cb->nlh, &filter, cb);
3239         if (err < 0)
3240                 return err;
3241
3242         err = rtm_dump_walk_nexthops(skb, cb, root, ctx,
3243                                      &rtm_dump_nexthop_cb, &filter);
3244         if (err < 0) {
3245                 if (likely(skb->len))
3246                         err = skb->len;
3247         }
3248
3249         cb->seq = net->nexthop.seq;
3250         nl_dump_check_consistent(cb, nlmsg_hdr(skb));
3251         return err;
3252 }
3253
3254 static struct nexthop *
3255 nexthop_find_group_resilient(struct net *net, u32 id,
3256                              struct netlink_ext_ack *extack)
3257 {
3258         struct nh_group *nhg;
3259         struct nexthop *nh;
3260
3261         nh = nexthop_find_by_id(net, id);
3262         if (!nh)
3263                 return ERR_PTR(-ENOENT);
3264
3265         if (!nh->is_group) {
3266                 NL_SET_ERR_MSG(extack, "Not a nexthop group");
3267                 return ERR_PTR(-EINVAL);
3268         }
3269
3270         nhg = rtnl_dereference(nh->nh_grp);
3271         if (!nhg->resilient) {
3272                 NL_SET_ERR_MSG(extack, "Nexthop group not of type resilient");
3273                 return ERR_PTR(-EINVAL);
3274         }
3275
3276         return nh;
3277 }
3278
3279 static int nh_valid_dump_nhid(struct nlattr *attr, u32 *nh_id_p,
3280                               struct netlink_ext_ack *extack)
3281 {
3282         u32 idx;
3283
3284         if (attr) {
3285                 idx = nla_get_u32(attr);
3286                 if (!idx) {
3287                         NL_SET_ERR_MSG(extack, "Invalid nexthop id");
3288                         return -EINVAL;
3289                 }
3290                 *nh_id_p = idx;
3291         } else {
3292                 *nh_id_p = 0;
3293         }
3294
3295         return 0;
3296 }
3297
3298 static int nh_valid_dump_bucket_req(const struct nlmsghdr *nlh,
3299                                     struct nh_dump_filter *filter,
3300                                     struct netlink_callback *cb)
3301 {
3302         struct nlattr *res_tb[ARRAY_SIZE(rtm_nh_res_bucket_policy_dump)];
3303         struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump_bucket)];
3304         int err;
3305
3306         err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3307                           ARRAY_SIZE(rtm_nh_policy_dump_bucket) - 1,
3308                           rtm_nh_policy_dump_bucket, NULL);
3309         if (err < 0)
3310                 return err;
3311
3312         err = nh_valid_dump_nhid(tb[NHA_ID], &filter->nh_id, cb->extack);
3313         if (err)
3314                 return err;
3315
3316         if (tb[NHA_RES_BUCKET]) {
3317                 size_t max = ARRAY_SIZE(rtm_nh_res_bucket_policy_dump) - 1;
3318
3319                 err = nla_parse_nested(res_tb, max,
3320                                        tb[NHA_RES_BUCKET],
3321                                        rtm_nh_res_bucket_policy_dump,
3322                                        cb->extack);
3323                 if (err < 0)
3324                         return err;
3325
3326                 err = nh_valid_dump_nhid(res_tb[NHA_RES_BUCKET_NH_ID],
3327                                          &filter->res_bucket_nh_id,
3328                                          cb->extack);
3329                 if (err)
3330                         return err;
3331         }
3332
3333         return __nh_valid_dump_req(nlh, tb, filter, cb->extack);
3334 }
3335
3336 struct rtm_dump_res_bucket_ctx {
3337         struct rtm_dump_nh_ctx nh;
3338         u16 bucket_index;
3339 };
3340
3341 static struct rtm_dump_res_bucket_ctx *
3342 rtm_dump_res_bucket_ctx(struct netlink_callback *cb)
3343 {
3344         struct rtm_dump_res_bucket_ctx *ctx = (void *)cb->ctx;
3345
3346         BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
3347         return ctx;
3348 }
3349
3350 struct rtm_dump_nexthop_bucket_data {
3351         struct rtm_dump_res_bucket_ctx *ctx;
3352         struct nh_dump_filter filter;
3353 };
3354
3355 static int rtm_dump_nexthop_bucket_nh(struct sk_buff *skb,
3356                                       struct netlink_callback *cb,
3357                                       struct nexthop *nh,
3358                                       struct rtm_dump_nexthop_bucket_data *dd)
3359 {
3360         u32 portid = NETLINK_CB(cb->skb).portid;
3361         struct nhmsg *nhm = nlmsg_data(cb->nlh);
3362         struct nh_res_table *res_table;
3363         struct nh_group *nhg;
3364         u16 bucket_index;
3365         int err;
3366
3367         nhg = rtnl_dereference(nh->nh_grp);
3368         res_table = rtnl_dereference(nhg->res_table);
3369         for (bucket_index = dd->ctx->bucket_index;
3370              bucket_index < res_table->num_nh_buckets;
3371              bucket_index++) {
3372                 struct nh_res_bucket *bucket;
3373                 struct nh_grp_entry *nhge;
3374
3375                 bucket = &res_table->nh_buckets[bucket_index];
3376                 nhge = rtnl_dereference(bucket->nh_entry);
3377                 if (nh_dump_filtered(nhge->nh, &dd->filter, nhm->nh_family))
3378                         continue;
3379
3380                 if (dd->filter.res_bucket_nh_id &&
3381                     dd->filter.res_bucket_nh_id != nhge->nh->id)
3382                         continue;
3383
3384                 dd->ctx->bucket_index = bucket_index;
3385                 err = nh_fill_res_bucket(skb, nh, bucket, bucket_index,
3386                                          RTM_NEWNEXTHOPBUCKET, portid,
3387                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
3388                                          cb->extack);
3389                 if (err)
3390                         return err;
3391         }
3392
3393         dd->ctx->bucket_index = 0;
3394
3395         return 0;
3396 }
3397
3398 static int rtm_dump_nexthop_bucket_cb(struct sk_buff *skb,
3399                                       struct netlink_callback *cb,
3400                                       struct nexthop *nh, void *data)
3401 {
3402         struct rtm_dump_nexthop_bucket_data *dd = data;
3403         struct nh_group *nhg;
3404
3405         if (!nh->is_group)
3406                 return 0;
3407
3408         nhg = rtnl_dereference(nh->nh_grp);
3409         if (!nhg->resilient)
3410                 return 0;
3411
3412         return rtm_dump_nexthop_bucket_nh(skb, cb, nh, dd);
3413 }
3414
3415 /* rtnl */
3416 static int rtm_dump_nexthop_bucket(struct sk_buff *skb,
3417                                    struct netlink_callback *cb)
3418 {
3419         struct rtm_dump_res_bucket_ctx *ctx = rtm_dump_res_bucket_ctx(cb);
3420         struct rtm_dump_nexthop_bucket_data dd = { .ctx = ctx };
3421         struct net *net = sock_net(skb->sk);
3422         struct nexthop *nh;
3423         int err;
3424
3425         err = nh_valid_dump_bucket_req(cb->nlh, &dd.filter, cb);
3426         if (err)
3427                 return err;
3428
3429         if (dd.filter.nh_id) {
3430                 nh = nexthop_find_group_resilient(net, dd.filter.nh_id,
3431                                                   cb->extack);
3432                 if (IS_ERR(nh))
3433                         return PTR_ERR(nh);
3434                 err = rtm_dump_nexthop_bucket_nh(skb, cb, nh, &dd);
3435         } else {
3436                 struct rb_root *root = &net->nexthop.rb_root;
3437
3438                 err = rtm_dump_walk_nexthops(skb, cb, root, &ctx->nh,
3439                                              &rtm_dump_nexthop_bucket_cb, &dd);
3440         }
3441
3442         if (err < 0) {
3443                 if (likely(skb->len))
3444                         err = skb->len;
3445         }
3446
3447         cb->seq = net->nexthop.seq;
3448         nl_dump_check_consistent(cb, nlmsg_hdr(skb));
3449         return err;
3450 }
3451
3452 static int nh_valid_get_bucket_req_res_bucket(struct nlattr *res,
3453                                               u16 *bucket_index,
3454                                               struct netlink_ext_ack *extack)
3455 {
3456         struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_bucket_policy_get)];
3457         int err;
3458
3459         err = nla_parse_nested(tb, ARRAY_SIZE(rtm_nh_res_bucket_policy_get) - 1,
3460                                res, rtm_nh_res_bucket_policy_get, extack);
3461         if (err < 0)
3462                 return err;
3463
3464         if (!tb[NHA_RES_BUCKET_INDEX]) {
3465                 NL_SET_ERR_MSG(extack, "Bucket index is missing");
3466                 return -EINVAL;
3467         }
3468
3469         *bucket_index = nla_get_u16(tb[NHA_RES_BUCKET_INDEX]);
3470         return 0;
3471 }
3472
3473 static int nh_valid_get_bucket_req(const struct nlmsghdr *nlh,
3474                                    u32 *id, u16 *bucket_index,
3475                                    struct netlink_ext_ack *extack)
3476 {
3477         struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get_bucket)];
3478         int err;
3479
3480         err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3481                           ARRAY_SIZE(rtm_nh_policy_get_bucket) - 1,
3482                           rtm_nh_policy_get_bucket, extack);
3483         if (err < 0)
3484                 return err;
3485
3486         err = __nh_valid_get_del_req(nlh, tb, id, extack);
3487         if (err)
3488                 return err;
3489
3490         if (!tb[NHA_RES_BUCKET]) {
3491                 NL_SET_ERR_MSG(extack, "Bucket information is missing");
3492                 return -EINVAL;
3493         }
3494
3495         err = nh_valid_get_bucket_req_res_bucket(tb[NHA_RES_BUCKET],
3496                                                  bucket_index, extack);
3497         if (err)
3498                 return err;
3499
3500         return 0;
3501 }
3502
3503 /* rtnl */
3504 static int rtm_get_nexthop_bucket(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3505                                   struct netlink_ext_ack *extack)
3506 {
3507         struct net *net = sock_net(in_skb->sk);
3508         struct nh_res_table *res_table;
3509         struct sk_buff *skb = NULL;
3510         struct nh_group *nhg;
3511         struct nexthop *nh;
3512         u16 bucket_index;
3513         int err;
3514         u32 id;
3515
3516         err = nh_valid_get_bucket_req(nlh, &id, &bucket_index, extack);
3517         if (err)
3518                 return err;
3519
3520         nh = nexthop_find_group_resilient(net, id, extack);
3521         if (IS_ERR(nh))
3522                 return PTR_ERR(nh);
3523
3524         nhg = rtnl_dereference(nh->nh_grp);
3525         res_table = rtnl_dereference(nhg->res_table);
3526         if (bucket_index >= res_table->num_nh_buckets) {
3527                 NL_SET_ERR_MSG(extack, "Bucket index out of bounds");
3528                 return -ENOENT;
3529         }
3530
3531         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3532         if (!skb)
3533                 return -ENOBUFS;
3534
3535         err = nh_fill_res_bucket(skb, nh, &res_table->nh_buckets[bucket_index],
3536                                  bucket_index, RTM_NEWNEXTHOPBUCKET,
3537                                  NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
3538                                  0, extack);
3539         if (err < 0) {
3540                 WARN_ON(err == -EMSGSIZE);
3541                 goto errout_free;
3542         }
3543
3544         return rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3545
3546 errout_free:
3547         kfree_skb(skb);
3548         return err;
3549 }
3550
3551 static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu)
3552 {
3553         unsigned int hash = nh_dev_hashfn(dev->ifindex);
3554         struct net *net = dev_net(dev);
3555         struct hlist_head *head = &net->nexthop.devhash[hash];
3556         struct hlist_node *n;
3557         struct nh_info *nhi;
3558
3559         hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
3560                 if (nhi->fib_nhc.nhc_dev == dev) {
3561                         if (nhi->family == AF_INET)
3562                                 fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu,
3563                                                    orig_mtu);
3564                 }
3565         }
3566 }
3567
3568 /* rtnl */
3569 static int nh_netdev_event(struct notifier_block *this,
3570                            unsigned long event, void *ptr)
3571 {
3572         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3573         struct netdev_notifier_info_ext *info_ext;
3574
3575         switch (event) {
3576         case NETDEV_DOWN:
3577         case NETDEV_UNREGISTER:
3578                 nexthop_flush_dev(dev, event);
3579                 break;
3580         case NETDEV_CHANGE:
3581                 if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP)))
3582                         nexthop_flush_dev(dev, event);
3583                 break;
3584         case NETDEV_CHANGEMTU:
3585                 info_ext = ptr;
3586                 nexthop_sync_mtu(dev, info_ext->ext.mtu);
3587                 rt_cache_flush(dev_net(dev));
3588                 break;
3589         }
3590         return NOTIFY_DONE;
3591 }
3592
3593 static struct notifier_block nh_netdev_notifier = {
3594         .notifier_call = nh_netdev_event,
3595 };
3596
3597 static int nexthops_dump(struct net *net, struct notifier_block *nb,
3598                          enum nexthop_event_type event_type,
3599                          struct netlink_ext_ack *extack)
3600 {
3601         struct rb_root *root = &net->nexthop.rb_root;
3602         struct rb_node *node;
3603         int err = 0;
3604
3605         for (node = rb_first(root); node; node = rb_next(node)) {
3606                 struct nexthop *nh;
3607
3608                 nh = rb_entry(node, struct nexthop, rb_node);
3609                 err = call_nexthop_notifier(nb, net, event_type, nh, extack);
3610                 if (err)
3611                         break;
3612         }
3613
3614         return err;
3615 }
3616
3617 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
3618                               struct netlink_ext_ack *extack)
3619 {
3620         int err;
3621
3622         rtnl_lock();
3623         err = nexthops_dump(net, nb, NEXTHOP_EVENT_REPLACE, extack);
3624         if (err)
3625                 goto unlock;
3626         err = blocking_notifier_chain_register(&net->nexthop.notifier_chain,
3627                                                nb);
3628 unlock:
3629         rtnl_unlock();
3630         return err;
3631 }
3632 EXPORT_SYMBOL(register_nexthop_notifier);
3633
3634 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
3635 {
3636         int err;
3637
3638         rtnl_lock();
3639         err = blocking_notifier_chain_unregister(&net->nexthop.notifier_chain,
3640                                                  nb);
3641         if (err)
3642                 goto unlock;
3643         nexthops_dump(net, nb, NEXTHOP_EVENT_DEL, NULL);
3644 unlock:
3645         rtnl_unlock();
3646         return err;
3647 }
3648 EXPORT_SYMBOL(unregister_nexthop_notifier);
3649
3650 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap)
3651 {
3652         struct nexthop *nexthop;
3653
3654         rcu_read_lock();
3655
3656         nexthop = nexthop_find_by_id(net, id);
3657         if (!nexthop)
3658                 goto out;
3659
3660         nexthop->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
3661         if (offload)
3662                 nexthop->nh_flags |= RTNH_F_OFFLOAD;
3663         if (trap)
3664                 nexthop->nh_flags |= RTNH_F_TRAP;
3665
3666 out:
3667         rcu_read_unlock();
3668 }
3669 EXPORT_SYMBOL(nexthop_set_hw_flags);
3670
3671 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
3672                                  bool offload, bool trap)
3673 {
3674         struct nh_res_table *res_table;
3675         struct nh_res_bucket *bucket;
3676         struct nexthop *nexthop;
3677         struct nh_group *nhg;
3678
3679         rcu_read_lock();
3680
3681         nexthop = nexthop_find_by_id(net, id);
3682         if (!nexthop || !nexthop->is_group)
3683                 goto out;
3684
3685         nhg = rcu_dereference(nexthop->nh_grp);
3686         if (!nhg->resilient)
3687                 goto out;
3688
3689         if (bucket_index >= nhg->res_table->num_nh_buckets)
3690                 goto out;
3691
3692         res_table = rcu_dereference(nhg->res_table);
3693         bucket = &res_table->nh_buckets[bucket_index];
3694         bucket->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
3695         if (offload)
3696                 bucket->nh_flags |= RTNH_F_OFFLOAD;
3697         if (trap)
3698                 bucket->nh_flags |= RTNH_F_TRAP;
3699
3700 out:
3701         rcu_read_unlock();
3702 }
3703 EXPORT_SYMBOL(nexthop_bucket_set_hw_flags);
3704
3705 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
3706                                      unsigned long *activity)
3707 {
3708         struct nh_res_table *res_table;
3709         struct nexthop *nexthop;
3710         struct nh_group *nhg;
3711         u16 i;
3712
3713         rcu_read_lock();
3714
3715         nexthop = nexthop_find_by_id(net, id);
3716         if (!nexthop || !nexthop->is_group)
3717                 goto out;
3718
3719         nhg = rcu_dereference(nexthop->nh_grp);
3720         if (!nhg->resilient)
3721                 goto out;
3722
3723         /* Instead of silently ignoring some buckets, demand that the sizes
3724          * be the same.
3725          */
3726         res_table = rcu_dereference(nhg->res_table);
3727         if (num_buckets != res_table->num_nh_buckets)
3728                 goto out;
3729
3730         for (i = 0; i < num_buckets; i++) {
3731                 if (test_bit(i, activity))
3732                         nh_res_bucket_set_busy(&res_table->nh_buckets[i]);
3733         }
3734
3735 out:
3736         rcu_read_unlock();
3737 }
3738 EXPORT_SYMBOL(nexthop_res_grp_activity_update);
3739
3740 static void __net_exit nexthop_net_exit_batch(struct list_head *net_list)
3741 {
3742         struct net *net;
3743
3744         rtnl_lock();
3745         list_for_each_entry(net, net_list, exit_list) {
3746                 flush_all_nexthops(net);
3747                 kfree(net->nexthop.devhash);
3748         }
3749         rtnl_unlock();
3750 }
3751
3752 static int __net_init nexthop_net_init(struct net *net)
3753 {
3754         size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE;
3755
3756         net->nexthop.rb_root = RB_ROOT;
3757         net->nexthop.devhash = kzalloc(sz, GFP_KERNEL);
3758         if (!net->nexthop.devhash)
3759                 return -ENOMEM;
3760         BLOCKING_INIT_NOTIFIER_HEAD(&net->nexthop.notifier_chain);
3761
3762         return 0;
3763 }
3764
3765 static struct pernet_operations nexthop_net_ops = {
3766         .init = nexthop_net_init,
3767         .exit_batch = nexthop_net_exit_batch,
3768 };
3769
3770 static int __init nexthop_init(void)
3771 {
3772         register_pernet_subsys(&nexthop_net_ops);
3773
3774         register_netdevice_notifier(&nh_netdev_notifier);
3775
3776         rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3777         rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0);
3778         rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop,
3779                       rtm_dump_nexthop, 0);
3780
3781         rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3782         rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
3783
3784         rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3785         rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
3786
3787         rtnl_register(PF_UNSPEC, RTM_GETNEXTHOPBUCKET, rtm_get_nexthop_bucket,
3788                       rtm_dump_nexthop_bucket, 0);
3789
3790         return 0;
3791 }
3792 subsys_initcall(nexthop_init);