net/ipv4/nexthop.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Generic nexthop implementation
0003  *
0004  * Copyright (c) 2017-19 Cumulus Networks
0005  * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
0006  */
0007
0008 #include <linux/nexthop.h>
0009 #include <linux/rtnetlink.h>
0010 #include <linux/slab.h>
0011 #include <linux/vmalloc.h>
0012 #include <net/arp.h>
0013 #include <net/ipv6_stubs.h>
0014 #include <net/lwtunnel.h>
0015 #include <net/ndisc.h>
0016 #include <net/nexthop.h>
0017 #include <net/route.h>
0018 #include <net/sock.h>
0019
0020 #define NH_RES_DEFAULT_IDLE_TIMER   (120 * HZ)
0021 #define NH_RES_DEFAULT_UNBALANCED_TIMER 0   /* No forced rebalancing. */
0022
0023 static void remove_nexthop(struct net *net, struct nexthop *nh,
0024                struct nl_info *nlinfo);
0025
0026 #define NH_DEV_HASHBITS  8
0027 #define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS)
0028
0029 static const struct nla_policy rtm_nh_policy_new[] = {
0030     [NHA_ID]        = { .type = NLA_U32 },
0031     [NHA_GROUP]     = { .type = NLA_BINARY },
0032     [NHA_GROUP_TYPE]    = { .type = NLA_U16 },
0033     [NHA_BLACKHOLE]     = { .type = NLA_FLAG },
0034     [NHA_OIF]       = { .type = NLA_U32 },
0035     [NHA_GATEWAY]       = { .type = NLA_BINARY },
0036     [NHA_ENCAP_TYPE]    = { .type = NLA_U16 },
0037     [NHA_ENCAP]     = { .type = NLA_NESTED },
0038     [NHA_FDB]       = { .type = NLA_FLAG },
0039     [NHA_RES_GROUP]     = { .type = NLA_NESTED },
0040 };
0041
0042 static const struct nla_policy rtm_nh_policy_get[] = {
0043     [NHA_ID]        = { .type = NLA_U32 },
0044 };
0045
0046 static const struct nla_policy rtm_nh_policy_dump[] = {
0047     [NHA_OIF]       = { .type = NLA_U32 },
0048     [NHA_GROUPS]        = { .type = NLA_FLAG },
0049     [NHA_MASTER]        = { .type = NLA_U32 },
0050     [NHA_FDB]       = { .type = NLA_FLAG },
0051 };
0052
0053 static const struct nla_policy rtm_nh_res_policy_new[] = {
0054     [NHA_RES_GROUP_BUCKETS]         = { .type = NLA_U16 },
0055     [NHA_RES_GROUP_IDLE_TIMER]      = { .type = NLA_U32 },
0056     [NHA_RES_GROUP_UNBALANCED_TIMER]    = { .type = NLA_U32 },
0057 };
0058
0059 static const struct nla_policy rtm_nh_policy_dump_bucket[] = {
0060     [NHA_ID]        = { .type = NLA_U32 },
0061     [NHA_OIF]       = { .type = NLA_U32 },
0062     [NHA_MASTER]        = { .type = NLA_U32 },
0063     [NHA_RES_BUCKET]    = { .type = NLA_NESTED },
0064 };
0065
0066 static const struct nla_policy rtm_nh_res_bucket_policy_dump[] = {
0067     [NHA_RES_BUCKET_NH_ID]  = { .type = NLA_U32 },
0068 };
0069
0070 static const struct nla_policy rtm_nh_policy_get_bucket[] = {
0071     [NHA_ID]        = { .type = NLA_U32 },
0072     [NHA_RES_BUCKET]    = { .type = NLA_NESTED },
0073 };
0074
0075 static const struct nla_policy rtm_nh_res_bucket_policy_get[] = {
0076     [NHA_RES_BUCKET_INDEX]  = { .type = NLA_U16 },
0077 };
0078
0079 static bool nexthop_notifiers_is_empty(struct net *net)
0080 {
0081     return !net->nexthop.notifier_chain.head;
0082 }
0083
0084 static void
0085 __nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
0086                    const struct nh_info *nhi)
0087 {
0088     nh_info->dev = nhi->fib_nhc.nhc_dev;
0089     nh_info->gw_family = nhi->fib_nhc.nhc_gw_family;
0090     if (nh_info->gw_family == AF_INET)
0091         nh_info->ipv4 = nhi->fib_nhc.nhc_gw.ipv4;
0092     else if (nh_info->gw_family == AF_INET6)
0093         nh_info->ipv6 = nhi->fib_nhc.nhc_gw.ipv6;
0094
0095     nh_info->is_reject = nhi->reject_nh;
0096     nh_info->is_fdb = nhi->fdb_nh;
0097     nh_info->has_encap = !!nhi->fib_nhc.nhc_lwtstate;
0098 }
0099
0100 static int nh_notifier_single_info_init(struct nh_notifier_info *info,
0101                     const struct nexthop *nh)
0102 {
0103     struct nh_info *nhi = rtnl_dereference(nh->nh_info);
0104
0105     info->type = NH_NOTIFIER_INFO_TYPE_SINGLE;
0106     info->nh = kzalloc(sizeof(*info->nh), GFP_KERNEL);
0107     if (!info->nh)
0108         return -ENOMEM;
0109
0110     __nh_notifier_single_info_init(info->nh, nhi);
0111
0112     return 0;
0113 }
0114
0115 static void nh_notifier_single_info_fini(struct nh_notifier_info *info)
0116 {
0117     kfree(info->nh);
0118 }
0119
0120 static int nh_notifier_mpath_info_init(struct nh_notifier_info *info,
0121                        struct nh_group *nhg)
0122 {
0123     u16 num_nh = nhg->num_nh;
0124     int i;
0125
0126     info->type = NH_NOTIFIER_INFO_TYPE_GRP;
0127     info->nh_grp = kzalloc(struct_size(info->nh_grp, nh_entries, num_nh),
0128                    GFP_KERNEL);
0129     if (!info->nh_grp)
0130         return -ENOMEM;
0131
0132     info->nh_grp->num_nh = num_nh;
0133     info->nh_grp->is_fdb = nhg->fdb_nh;
0134
0135     for (i = 0; i < num_nh; i++) {
0136         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
0137         struct nh_info *nhi;
0138
0139         nhi = rtnl_dereference(nhge->nh->nh_info);
0140         info->nh_grp->nh_entries[i].id = nhge->nh->id;
0141         info->nh_grp->nh_entries[i].weight = nhge->weight;
0142         __nh_notifier_single_info_init(&info->nh_grp->nh_entries[i].nh,
0143                            nhi);
0144     }
0145
0146     return 0;
0147 }
0148
0149 static int nh_notifier_res_table_info_init(struct nh_notifier_info *info,
0150                        struct nh_group *nhg)
0151 {
0152     struct nh_res_table *res_table = rtnl_dereference(nhg->res_table);
0153     u16 num_nh_buckets = res_table->num_nh_buckets;
0154     unsigned long size;
0155     u16 i;
0156
0157     info->type = NH_NOTIFIER_INFO_TYPE_RES_TABLE;
0158     size = struct_size(info->nh_res_table, nhs, num_nh_buckets);
0159     info->nh_res_table = __vmalloc(size, GFP_KERNEL | __GFP_ZERO |
0160                        __GFP_NOWARN);
0161     if (!info->nh_res_table)
0162         return -ENOMEM;
0163
0164     info->nh_res_table->num_nh_buckets = num_nh_buckets;
0165
0166     for (i = 0; i < num_nh_buckets; i++) {
0167         struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
0168         struct nh_grp_entry *nhge;
0169         struct nh_info *nhi;
0170
0171         nhge = rtnl_dereference(bucket->nh_entry);
0172         nhi = rtnl_dereference(nhge->nh->nh_info);
0173         __nh_notifier_single_info_init(&info->nh_res_table->nhs[i],
0174                            nhi);
0175     }
0176
0177     return 0;
0178 }
0179
0180 static int nh_notifier_grp_info_init(struct nh_notifier_info *info,
0181                      const struct nexthop *nh)
0182 {
0183     struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
0184
0185     if (nhg->hash_threshold)
0186         return nh_notifier_mpath_info_init(info, nhg);
0187     else if (nhg->resilient)
0188         return nh_notifier_res_table_info_init(info, nhg);
0189     return -EINVAL;
0190 }
0191
0192 static void nh_notifier_grp_info_fini(struct nh_notifier_info *info,
0193                       const struct nexthop *nh)
0194 {
0195     struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
0196
0197     if (nhg->hash_threshold)
0198         kfree(info->nh_grp);
0199     else if (nhg->resilient)
0200         vfree(info->nh_res_table);
0201 }
0202
0203 static int nh_notifier_info_init(struct nh_notifier_info *info,
0204                  const struct nexthop *nh)
0205 {
0206     info->id = nh->id;
0207
0208     if (nh->is_group)
0209         return nh_notifier_grp_info_init(info, nh);
0210     else
0211         return nh_notifier_single_info_init(info, nh);
0212 }
0213
0214 static void nh_notifier_info_fini(struct nh_notifier_info *info,
0215                   const struct nexthop *nh)
0216 {
0217     if (nh->is_group)
0218         nh_notifier_grp_info_fini(info, nh);
0219     else
0220         nh_notifier_single_info_fini(info);
0221 }
0222
0223 static int call_nexthop_notifiers(struct net *net,
0224                   enum nexthop_event_type event_type,
0225                   struct nexthop *nh,
0226                   struct netlink_ext_ack *extack)
0227 {
0228     struct nh_notifier_info info = {
0229         .net = net,
0230         .extack = extack,
0231     };
0232     int err;
0233
0234     ASSERT_RTNL();
0235
0236     if (nexthop_notifiers_is_empty(net))
0237         return 0;
0238
0239     err = nh_notifier_info_init(&info, nh);
0240     if (err) {
0241         NL_SET_ERR_MSG(extack, "Failed to initialize nexthop notifier info");
0242         return err;
0243     }
0244
0245     err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
0246                        event_type, &info);
0247     nh_notifier_info_fini(&info, nh);
0248
0249     return notifier_to_errno(err);
0250 }
0251
0252 static int
0253 nh_notifier_res_bucket_idle_timer_get(const struct nh_notifier_info *info,
0254                       bool force, unsigned int *p_idle_timer_ms)
0255 {
0256     struct nh_res_table *res_table;
0257     struct nh_group *nhg;
0258     struct nexthop *nh;
0259     int err = 0;
0260
0261     /* When 'force' is false, nexthop bucket replacement is performed
0262      * because the bucket was deemed to be idle. In this case, capable
0263      * listeners can choose to perform an atomic replacement: The bucket is
0264      * only replaced if it is inactive. However, if the idle timer interval
0265      * is smaller than the interval in which a listener is querying
0266      * buckets' activity from the device, then atomic replacement should
0267      * not be tried. Pass the idle timer value to listeners, so that they
0268      * could determine which type of replacement to perform.
0269      */
0270     if (force) {
0271         *p_idle_timer_ms = 0;
0272         return 0;
0273     }
0274
0275     rcu_read_lock();
0276
0277     nh = nexthop_find_by_id(info->net, info->id);
0278     if (!nh) {
0279         err = -EINVAL;
0280         goto out;
0281     }
0282
0283     nhg = rcu_dereference(nh->nh_grp);
0284     res_table = rcu_dereference(nhg->res_table);
0285     *p_idle_timer_ms = jiffies_to_msecs(res_table->idle_timer);
0286
0287 out:
0288     rcu_read_unlock();
0289
0290     return err;
0291 }
0292
0293 static int nh_notifier_res_bucket_info_init(struct nh_notifier_info *info,
0294                         u16 bucket_index, bool force,
0295                         struct nh_info *oldi,
0296                         struct nh_info *newi)
0297 {
0298     unsigned int idle_timer_ms;
0299     int err;
0300
0301     err = nh_notifier_res_bucket_idle_timer_get(info, force,
0302                             &idle_timer_ms);
0303     if (err)
0304         return err;
0305
0306     info->type = NH_NOTIFIER_INFO_TYPE_RES_BUCKET;
0307     info->nh_res_bucket = kzalloc(sizeof(*info->nh_res_bucket),
0308                       GFP_KERNEL);
0309     if (!info->nh_res_bucket)
0310         return -ENOMEM;
0311
0312     info->nh_res_bucket->bucket_index = bucket_index;
0313     info->nh_res_bucket->idle_timer_ms = idle_timer_ms;
0314     info->nh_res_bucket->force = force;
0315     __nh_notifier_single_info_init(&info->nh_res_bucket->old_nh, oldi);
0316     __nh_notifier_single_info_init(&info->nh_res_bucket->new_nh, newi);
0317     return 0;
0318 }
0319
0320 static void nh_notifier_res_bucket_info_fini(struct nh_notifier_info *info)
0321 {
0322     kfree(info->nh_res_bucket);
0323 }
0324
0325 static int __call_nexthop_res_bucket_notifiers(struct net *net, u32 nhg_id,
0326                            u16 bucket_index, bool force,
0327                            struct nh_info *oldi,
0328                            struct nh_info *newi,
0329                            struct netlink_ext_ack *extack)
0330 {
0331     struct nh_notifier_info info = {
0332         .net = net,
0333         .extack = extack,
0334         .id = nhg_id,
0335     };
0336     int err;
0337
0338     if (nexthop_notifiers_is_empty(net))
0339         return 0;
0340
0341     err = nh_notifier_res_bucket_info_init(&info, bucket_index, force,
0342                            oldi, newi);
0343     if (err)
0344         return err;
0345
0346     err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
0347                        NEXTHOP_EVENT_BUCKET_REPLACE, &info);
0348     nh_notifier_res_bucket_info_fini(&info);
0349
0350     return notifier_to_errno(err);
0351 }
0352
0353 /* There are three users of RES_TABLE, and NHs etc. referenced from there:
0354  *
0355  * 1) a collection of callbacks for NH maintenance. This operates under
0356  *    RTNL,
0357  * 2) the delayed work that gradually balances the resilient table,
0358  * 3) and nexthop_select_path(), operating under RCU.
0359  *
0360  * Both the delayed work and the RTNL block are writers, and need to
0361  * maintain mutual exclusion. Since there are only two and well-known
0362  * writers for each table, the RTNL code can make sure it has exclusive
0363  * access thus:
0364  *
0365  * - Have the DW operate without locking;
0366  * - synchronously cancel the DW;
0367  * - do the writing;
0368  * - if the write was not actually a delete, call upkeep, which schedules
0369  *   DW again if necessary.
0370  *
0371  * The functions that are always called from the RTNL context use
0372  * rtnl_dereference(). The functions that can also be called from the DW do
0373  * a raw dereference and rely on the above mutual exclusion scheme.
0374  */
0375 #define nh_res_dereference(p) (rcu_dereference_raw(p))
0376
0377 static int call_nexthop_res_bucket_notifiers(struct net *net, u32 nhg_id,
0378                          u16 bucket_index, bool force,
0379                          struct nexthop *old_nh,
0380                          struct nexthop *new_nh,
0381                          struct netlink_ext_ack *extack)
0382 {
0383     struct nh_info *oldi = nh_res_dereference(old_nh->nh_info);
0384     struct nh_info *newi = nh_res_dereference(new_nh->nh_info);
0385
0386     return __call_nexthop_res_bucket_notifiers(net, nhg_id, bucket_index,
0387                            force, oldi, newi, extack);
0388 }
0389
0390 static int call_nexthop_res_table_notifiers(struct net *net, struct nexthop *nh,
0391                         struct netlink_ext_ack *extack)
0392 {
0393     struct nh_notifier_info info = {
0394         .net = net,
0395         .extack = extack,
0396     };
0397     struct nh_group *nhg;
0398     int err;
0399
0400     ASSERT_RTNL();
0401
0402     if (nexthop_notifiers_is_empty(net))
0403         return 0;
0404
0405     /* At this point, the nexthop buckets are still not populated. Only
0406      * emit a notification with the logical nexthops, so that a listener
0407      * could potentially veto it in case of unsupported configuration.
0408      */
0409     nhg = rtnl_dereference(nh->nh_grp);
0410     err = nh_notifier_mpath_info_init(&info, nhg);
0411     if (err) {
0412         NL_SET_ERR_MSG(extack, "Failed to initialize nexthop notifier info");
0413         return err;
0414     }
0415
0416     err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
0417                        NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
0418                        &info);
0419     kfree(info.nh_grp);
0420
0421     return notifier_to_errno(err);
0422 }
0423
0424 static int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
0425                  enum nexthop_event_type event_type,
0426                  struct nexthop *nh,
0427                  struct netlink_ext_ack *extack)
0428 {
0429     struct nh_notifier_info info = {
0430         .net = net,
0431         .extack = extack,
0432     };
0433     int err;
0434
0435     err = nh_notifier_info_init(&info, nh);
0436     if (err)
0437         return err;
0438
0439     err = nb->notifier_call(nb, event_type, &info);
0440     nh_notifier_info_fini(&info, nh);
0441
0442     return notifier_to_errno(err);
0443 }
0444
0445 static unsigned int nh_dev_hashfn(unsigned int val)
0446 {
0447     unsigned int mask = NH_DEV_HASHSIZE - 1;
0448
0449     return (val ^
0450         (val >> NH_DEV_HASHBITS) ^
0451         (val >> (NH_DEV_HASHBITS * 2))) & mask;
0452 }
0453
0454 static void nexthop_devhash_add(struct net *net, struct nh_info *nhi)
0455 {
0456     struct net_device *dev = nhi->fib_nhc.nhc_dev;
0457     struct hlist_head *head;
0458     unsigned int hash;
0459
0460     WARN_ON(!dev);
0461
0462     hash = nh_dev_hashfn(dev->ifindex);
0463     head = &net->nexthop.devhash[hash];
0464     hlist_add_head(&nhi->dev_hash, head);
0465 }
0466
0467 static void nexthop_free_group(struct nexthop *nh)
0468 {
0469     struct nh_group *nhg;
0470     int i;
0471
0472     nhg = rcu_dereference_raw(nh->nh_grp);
0473     for (i = 0; i < nhg->num_nh; ++i) {
0474         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
0475
0476         WARN_ON(!list_empty(&nhge->nh_list));
0477         nexthop_put(nhge->nh);
0478     }
0479
0480     WARN_ON(nhg->spare == nhg);
0481
0482     if (nhg->resilient)
0483         vfree(rcu_dereference_raw(nhg->res_table));
0484
0485     kfree(nhg->spare);
0486     kfree(nhg);
0487 }
0488
0489 static void nexthop_free_single(struct nexthop *nh)
0490 {
0491     struct nh_info *nhi;
0492
0493     nhi = rcu_dereference_raw(nh->nh_info);
0494     switch (nhi->family) {
0495     case AF_INET:
0496         fib_nh_release(nh->net, &nhi->fib_nh);
0497         break;
0498     case AF_INET6:
0499         ipv6_stub->fib6_nh_release(&nhi->fib6_nh);
0500         break;
0501     }
0502     kfree(nhi);
0503 }
0504
0505 void nexthop_free_rcu(struct rcu_head *head)
0506 {
0507     struct nexthop *nh = container_of(head, struct nexthop, rcu);
0508
0509     if (nh->is_group)
0510         nexthop_free_group(nh);
0511     else
0512         nexthop_free_single(nh);
0513
0514     kfree(nh);
0515 }
0516 EXPORT_SYMBOL_GPL(nexthop_free_rcu);
0517
0518 static struct nexthop *nexthop_alloc(void)
0519 {
0520     struct nexthop *nh;
0521
0522     nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
0523     if (nh) {
0524         INIT_LIST_HEAD(&nh->fi_list);
0525         INIT_LIST_HEAD(&nh->f6i_list);
0526         INIT_LIST_HEAD(&nh->grp_list);
0527         INIT_LIST_HEAD(&nh->fdb_list);
0528     }
0529     return nh;
0530 }
0531
0532 static struct nh_group *nexthop_grp_alloc(u16 num_nh)
0533 {
0534     struct nh_group *nhg;
0535
0536     nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL);
0537     if (nhg)
0538         nhg->num_nh = num_nh;
0539
0540     return nhg;
0541 }
0542
0543 static void nh_res_table_upkeep_dw(struct work_struct *work);
0544
0545 static struct nh_res_table *
0546 nexthop_res_table_alloc(struct net *net, u32 nhg_id, struct nh_config *cfg)
0547 {
0548     const u16 num_nh_buckets = cfg->nh_grp_res_num_buckets;
0549     struct nh_res_table *res_table;
0550     unsigned long size;
0551
0552     size = struct_size(res_table, nh_buckets, num_nh_buckets);
0553     res_table = __vmalloc(size, GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
0554     if (!res_table)
0555         return NULL;
0556
0557     res_table->net = net;
0558     res_table->nhg_id = nhg_id;
0559     INIT_DELAYED_WORK(&res_table->upkeep_dw, &nh_res_table_upkeep_dw);
0560     INIT_LIST_HEAD(&res_table->uw_nh_entries);
0561     res_table->idle_timer = cfg->nh_grp_res_idle_timer;
0562     res_table->unbalanced_timer = cfg->nh_grp_res_unbalanced_timer;
0563     res_table->num_nh_buckets = num_nh_buckets;
0564     return res_table;
0565 }
0566
0567 static void nh_base_seq_inc(struct net *net)
0568 {
0569     while (++net->nexthop.seq == 0)
0570         ;
0571 }
0572
0573 /* no reference taken; rcu lock or rtnl must be held */
0574 struct nexthop *nexthop_find_by_id(struct net *net, u32 id)
0575 {
0576     struct rb_node **pp, *parent = NULL, *next;
0577
0578     pp = &net->nexthop.rb_root.rb_node;
0579     while (1) {
0580         struct nexthop *nh;
0581
0582         next = rcu_dereference_raw(*pp);
0583         if (!next)
0584             break;
0585         parent = next;
0586
0587         nh = rb_entry(parent, struct nexthop, rb_node);
0588         if (id < nh->id)
0589             pp = &next->rb_left;
0590         else if (id > nh->id)
0591             pp = &next->rb_right;
0592         else
0593             return nh;
0594     }
0595     return NULL;
0596 }
0597 EXPORT_SYMBOL_GPL(nexthop_find_by_id);
0598
0599 /* used for auto id allocation; called with rtnl held */
0600 static u32 nh_find_unused_id(struct net *net)
0601 {
0602     u32 id_start = net->nexthop.last_id_allocated;
0603
0604     while (1) {
0605         net->nexthop.last_id_allocated++;
0606         if (net->nexthop.last_id_allocated == id_start)
0607             break;
0608
0609         if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated))
0610             return net->nexthop.last_id_allocated;
0611     }
0612     return 0;
0613 }
0614
0615 static void nh_res_time_set_deadline(unsigned long next_time,
0616                      unsigned long *deadline)
0617 {
0618     if (time_before(next_time, *deadline))
0619         *deadline = next_time;
0620 }
0621
0622 static clock_t nh_res_table_unbalanced_time(struct nh_res_table *res_table)
0623 {
0624     if (list_empty(&res_table->uw_nh_entries))
0625         return 0;
0626     return jiffies_delta_to_clock_t(jiffies - res_table->unbalanced_since);
0627 }
0628
0629 static int nla_put_nh_group_res(struct sk_buff *skb, struct nh_group *nhg)
0630 {
0631     struct nh_res_table *res_table = rtnl_dereference(nhg->res_table);
0632     struct nlattr *nest;
0633
0634     nest = nla_nest_start(skb, NHA_RES_GROUP);
0635     if (!nest)
0636         return -EMSGSIZE;
0637
0638     if (nla_put_u16(skb, NHA_RES_GROUP_BUCKETS,
0639             res_table->num_nh_buckets) ||
0640         nla_put_u32(skb, NHA_RES_GROUP_IDLE_TIMER,
0641             jiffies_to_clock_t(res_table->idle_timer)) ||
0642         nla_put_u32(skb, NHA_RES_GROUP_UNBALANCED_TIMER,
0643             jiffies_to_clock_t(res_table->unbalanced_timer)) ||
0644         nla_put_u64_64bit(skb, NHA_RES_GROUP_UNBALANCED_TIME,
0645                   nh_res_table_unbalanced_time(res_table),
0646                   NHA_RES_GROUP_PAD))
0647         goto nla_put_failure;
0648
0649     nla_nest_end(skb, nest);
0650     return 0;
0651
0652 nla_put_failure:
0653     nla_nest_cancel(skb, nest);
0654     return -EMSGSIZE;
0655 }
0656
0657 static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
0658 {
0659     struct nexthop_grp *p;
0660     size_t len = nhg->num_nh * sizeof(*p);
0661     struct nlattr *nla;
0662     u16 group_type = 0;
0663     int i;
0664
0665     if (nhg->hash_threshold)
0666         group_type = NEXTHOP_GRP_TYPE_MPATH;
0667     else if (nhg->resilient)
0668         group_type = NEXTHOP_GRP_TYPE_RES;
0669
0670     if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type))
0671         goto nla_put_failure;
0672
0673     nla = nla_reserve(skb, NHA_GROUP, len);
0674     if (!nla)
0675         goto nla_put_failure;
0676
0677     p = nla_data(nla);
0678     for (i = 0; i < nhg->num_nh; ++i) {
0679         p->id = nhg->nh_entries[i].nh->id;
0680         p->weight = nhg->nh_entries[i].weight - 1;
0681         p += 1;
0682     }
0683
0684     if (nhg->resilient && nla_put_nh_group_res(skb, nhg))
0685         goto nla_put_failure;
0686
0687     return 0;
0688
0689 nla_put_failure:
0690     return -EMSGSIZE;
0691 }
0692
0693 static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
0694             int event, u32 portid, u32 seq, unsigned int nlflags)
0695 {
0696     struct fib6_nh *fib6_nh;
0697     struct fib_nh *fib_nh;
0698     struct nlmsghdr *nlh;
0699     struct nh_info *nhi;
0700     struct nhmsg *nhm;
0701
0702     nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
0703     if (!nlh)
0704         return -EMSGSIZE;
0705
0706     nhm = nlmsg_data(nlh);
0707     nhm->nh_family = AF_UNSPEC;
0708     nhm->nh_flags = nh->nh_flags;
0709     nhm->nh_protocol = nh->protocol;
0710     nhm->nh_scope = 0;
0711     nhm->resvd = 0;
0712
0713     if (nla_put_u32(skb, NHA_ID, nh->id))
0714         goto nla_put_failure;
0715
0716     if (nh->is_group) {
0717         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
0718
0719         if (nhg->fdb_nh && nla_put_flag(skb, NHA_FDB))
0720             goto nla_put_failure;
0721         if (nla_put_nh_group(skb, nhg))
0722             goto nla_put_failure;
0723         goto out;
0724     }
0725
0726     nhi = rtnl_dereference(nh->nh_info);
0727     nhm->nh_family = nhi->family;
0728     if (nhi->reject_nh) {
0729         if (nla_put_flag(skb, NHA_BLACKHOLE))
0730             goto nla_put_failure;
0731         goto out;
0732     } else if (nhi->fdb_nh) {
0733         if (nla_put_flag(skb, NHA_FDB))
0734             goto nla_put_failure;
0735     } else {
0736         const struct net_device *dev;
0737
0738         dev = nhi->fib_nhc.nhc_dev;
0739         if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex))
0740             goto nla_put_failure;
0741     }
0742
0743     nhm->nh_scope = nhi->fib_nhc.nhc_scope;
0744     switch (nhi->family) {
0745     case AF_INET:
0746         fib_nh = &nhi->fib_nh;
0747         if (fib_nh->fib_nh_gw_family &&
0748             nla_put_be32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4))
0749             goto nla_put_failure;
0750         break;
0751
0752     case AF_INET6:
0753         fib6_nh = &nhi->fib6_nh;
0754         if (fib6_nh->fib_nh_gw_family &&
0755             nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6))
0756             goto nla_put_failure;
0757         break;
0758     }
0759
0760     if (nhi->fib_nhc.nhc_lwtstate &&
0761         lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate,
0762                 NHA_ENCAP, NHA_ENCAP_TYPE) < 0)
0763         goto nla_put_failure;
0764
0765 out:
0766     nlmsg_end(skb, nlh);
0767     return 0;
0768
0769 nla_put_failure:
0770     nlmsg_cancel(skb, nlh);
0771     return -EMSGSIZE;
0772 }
0773
0774 static size_t nh_nlmsg_size_grp_res(struct nh_group *nhg)
0775 {
0776     return nla_total_size(0) +  /* NHA_RES_GROUP */
0777         nla_total_size(2) + /* NHA_RES_GROUP_BUCKETS */
0778         nla_total_size(4) + /* NHA_RES_GROUP_IDLE_TIMER */
0779         nla_total_size(4) + /* NHA_RES_GROUP_UNBALANCED_TIMER */
0780         nla_total_size_64bit(8);/* NHA_RES_GROUP_UNBALANCED_TIME */
0781 }
0782
0783 static size_t nh_nlmsg_size_grp(struct nexthop *nh)
0784 {
0785     struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
0786     size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh;
0787     size_t tot = nla_total_size(sz) +
0788         nla_total_size(2); /* NHA_GROUP_TYPE */
0789
0790     if (nhg->resilient)
0791         tot += nh_nlmsg_size_grp_res(nhg);
0792
0793     return tot;
0794 }
0795
0796 static size_t nh_nlmsg_size_single(struct nexthop *nh)
0797 {
0798     struct nh_info *nhi = rtnl_dereference(nh->nh_info);
0799     size_t sz;
0800
0801     /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE
0802      * are mutually exclusive
0803      */
0804     sz = nla_total_size(4);  /* NHA_OIF */
0805
0806     switch (nhi->family) {
0807     case AF_INET:
0808         if (nhi->fib_nh.fib_nh_gw_family)
0809             sz += nla_total_size(4);  /* NHA_GATEWAY */
0810         break;
0811
0812     case AF_INET6:
0813         /* NHA_GATEWAY */
0814         if (nhi->fib6_nh.fib_nh_gw_family)
0815             sz += nla_total_size(sizeof(const struct in6_addr));
0816         break;
0817     }
0818
0819     if (nhi->fib_nhc.nhc_lwtstate) {
0820         sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate);
0821         sz += nla_total_size(2);  /* NHA_ENCAP_TYPE */
0822     }
0823
0824     return sz;
0825 }
0826
0827 static size_t nh_nlmsg_size(struct nexthop *nh)
0828 {
0829     size_t sz = NLMSG_ALIGN(sizeof(struct nhmsg));
0830
0831     sz += nla_total_size(4); /* NHA_ID */
0832
0833     if (nh->is_group)
0834         sz += nh_nlmsg_size_grp(nh);
0835     else
0836         sz += nh_nlmsg_size_single(nh);
0837
0838     return sz;
0839 }
0840
0841 static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info)
0842 {
0843     unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0;
0844     u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
0845     struct sk_buff *skb;
0846     int err = -ENOBUFS;
0847
0848     skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any());
0849     if (!skb)
0850         goto errout;
0851
0852     err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags);
0853     if (err < 0) {
0854         /* -EMSGSIZE implies BUG in nh_nlmsg_size() */
0855         WARN_ON(err == -EMSGSIZE);
0856         kfree_skb(skb);
0857         goto errout;
0858     }
0859
0860     rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP,
0861             info->nlh, gfp_any());
0862     return;
0863 errout:
0864     if (err < 0)
0865         rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err);
0866 }
0867
0868 static unsigned long nh_res_bucket_used_time(const struct nh_res_bucket *bucket)
0869 {
0870     return (unsigned long)atomic_long_read(&bucket->used_time);
0871 }
0872
0873 static unsigned long
0874 nh_res_bucket_idle_point(const struct nh_res_table *res_table,
0875              const struct nh_res_bucket *bucket,
0876              unsigned long now)
0877 {
0878     unsigned long time = nh_res_bucket_used_time(bucket);
0879
0880     /* Bucket was not used since it was migrated. The idle time is now. */
0881     if (time == bucket->migrated_time)
0882         return now;
0883
0884     return time + res_table->idle_timer;
0885 }
0886
0887 static unsigned long
0888 nh_res_table_unb_point(const struct nh_res_table *res_table)
0889 {
0890     return res_table->unbalanced_since + res_table->unbalanced_timer;
0891 }
0892
0893 static void nh_res_bucket_set_idle(const struct nh_res_table *res_table,
0894                    struct nh_res_bucket *bucket)
0895 {
0896     unsigned long now = jiffies;
0897
0898     atomic_long_set(&bucket->used_time, (long)now);
0899     bucket->migrated_time = now;
0900 }
0901
0902 static void nh_res_bucket_set_busy(struct nh_res_bucket *bucket)
0903 {
0904     atomic_long_set(&bucket->used_time, (long)jiffies);
0905 }
0906
0907 static clock_t nh_res_bucket_idle_time(const struct nh_res_bucket *bucket)
0908 {
0909     unsigned long used_time = nh_res_bucket_used_time(bucket);
0910
0911     return jiffies_delta_to_clock_t(jiffies - used_time);
0912 }
0913
0914 static int nh_fill_res_bucket(struct sk_buff *skb, struct nexthop *nh,
0915                   struct nh_res_bucket *bucket, u16 bucket_index,
0916                   int event, u32 portid, u32 seq,
0917                   unsigned int nlflags,
0918                   struct netlink_ext_ack *extack)
0919 {
0920     struct nh_grp_entry *nhge = nh_res_dereference(bucket->nh_entry);
0921     struct nlmsghdr *nlh;
0922     struct nlattr *nest;
0923     struct nhmsg *nhm;
0924
0925     nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
0926     if (!nlh)
0927         return -EMSGSIZE;
0928
0929     nhm = nlmsg_data(nlh);
0930     nhm->nh_family = AF_UNSPEC;
0931     nhm->nh_flags = bucket->nh_flags;
0932     nhm->nh_protocol = nh->protocol;
0933     nhm->nh_scope = 0;
0934     nhm->resvd = 0;
0935
0936     if (nla_put_u32(skb, NHA_ID, nh->id))
0937         goto nla_put_failure;
0938
0939     nest = nla_nest_start(skb, NHA_RES_BUCKET);
0940     if (!nest)
0941         goto nla_put_failure;
0942
0943     if (nla_put_u16(skb, NHA_RES_BUCKET_INDEX, bucket_index) ||
0944         nla_put_u32(skb, NHA_RES_BUCKET_NH_ID, nhge->nh->id) ||
0945         nla_put_u64_64bit(skb, NHA_RES_BUCKET_IDLE_TIME,
0946                   nh_res_bucket_idle_time(bucket),
0947                   NHA_RES_BUCKET_PAD))
0948         goto nla_put_failure_nest;
0949
0950     nla_nest_end(skb, nest);
0951     nlmsg_end(skb, nlh);
0952     return 0;
0953
0954 nla_put_failure_nest:
0955     nla_nest_cancel(skb, nest);
0956 nla_put_failure:
0957     nlmsg_cancel(skb, nlh);
0958     return -EMSGSIZE;
0959 }
0960
0961 static void nexthop_bucket_notify(struct nh_res_table *res_table,
0962                   u16 bucket_index)
0963 {
0964     struct nh_res_bucket *bucket = &res_table->nh_buckets[bucket_index];
0965     struct nh_grp_entry *nhge = nh_res_dereference(bucket->nh_entry);
0966     struct nexthop *nh = nhge->nh_parent;
0967     struct sk_buff *skb;
0968     int err = -ENOBUFS;
0969
0970     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
0971     if (!skb)
0972         goto errout;
0973
0974     err = nh_fill_res_bucket(skb, nh, bucket, bucket_index,
0975                  RTM_NEWNEXTHOPBUCKET, 0, 0, NLM_F_REPLACE,
0976                  NULL);
0977     if (err < 0) {
0978         kfree_skb(skb);
0979         goto errout;
0980     }
0981
0982     rtnl_notify(skb, nh->net, 0, RTNLGRP_NEXTHOP, NULL, GFP_KERNEL);
0983     return;
0984 errout:
0985     if (err < 0)
0986         rtnl_set_sk_err(nh->net, RTNLGRP_NEXTHOP, err);
0987 }
0988
0989 static bool valid_group_nh(struct nexthop *nh, unsigned int npaths,
0990                bool *is_fdb, struct netlink_ext_ack *extack)
0991 {
0992     if (nh->is_group) {
0993         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
0994
0995         /* Nesting groups within groups is not supported. */
0996         if (nhg->hash_threshold) {
0997             NL_SET_ERR_MSG(extack,
0998                        "Hash-threshold group can not be a nexthop within a group");
0999             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_bh();
1128
1129     n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6);
1130     if (n)
1131         state = n->nud_state;
1132
1133     rcu_read_unlock_bh();
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_bh();
1144
1145     n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
1146                       (__force u32)nh->fib_nh_gw4);
1147     if (n)
1148         state = n->nud_state;
1149
1150     rcu_read_unlock_bh();
1151
1152     return !!(state & NUD_VALID);
1153 }
1154
1155 static struct nexthop *nexthop_select_path_hthr(struct nh_group *nhg, int hash)
1156 {
1157     struct nexthop *rc = NULL;
1158     int i;
1159
1160     for (i = 0; i < nhg->num_nh; ++i) {
1161         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1162         struct nh_info *nhi;
1163
1164         if (hash > atomic_read(&nhge->hthr.upper_bound))
1165             continue;
1166
1167         nhi = rcu_dereference(nhge->nh->nh_info);
1168         if (nhi->fdb_nh)
1169             return nhge->nh;
1170
1171         /* nexthops always check if it is good and does
1172          * not rely on a sysctl for this behavior
1173          */
1174         switch (nhi->family) {
1175         case AF_INET:
1176             if (ipv4_good_nh(&nhi->fib_nh))
1177                 return nhge->nh;
1178             break;
1179         case AF_INET6:
1180             if (ipv6_good_nh(&nhi->fib6_nh))
1181                 return nhge->nh;
1182             break;
1183         }
1184
1185         if (!rc)
1186             rc = nhge->nh;
1187     }
1188
1189     return rc;
1190 }
1191
1192 static struct nexthop *nexthop_select_path_res(struct nh_group *nhg, int hash)
1193 {
1194     struct nh_res_table *res_table = rcu_dereference(nhg->res_table);
1195     u16 bucket_index = hash % res_table->num_nh_buckets;
1196     struct nh_res_bucket *bucket;
1197     struct nh_grp_entry *nhge;
1198
1199     /* nexthop_select_path() is expected to return a non-NULL value, so
1200      * skip protocol validation and just hand out whatever there is.
1201      */
1202     bucket = &res_table->nh_buckets[bucket_index];
1203     nh_res_bucket_set_busy(bucket);
1204     nhge = rcu_dereference(bucket->nh_entry);
1205     return nhge->nh;
1206 }
1207
1208 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash)
1209 {
1210     struct nh_group *nhg;
1211
1212     if (!nh->is_group)
1213         return nh;
1214
1215     nhg = rcu_dereference(nh->nh_grp);
1216     if (nhg->hash_threshold)
1217         return nexthop_select_path_hthr(nhg, hash);
1218     else if (nhg->resilient)
1219         return nexthop_select_path_res(nhg, hash);
1220
1221     /* Unreachable. */
1222     return NULL;
1223 }
1224 EXPORT_SYMBOL_GPL(nexthop_select_path);
1225
1226 int nexthop_for_each_fib6_nh(struct nexthop *nh,
1227                  int (*cb)(struct fib6_nh *nh, void *arg),
1228                  void *arg)
1229 {
1230     struct nh_info *nhi;
1231     int err;
1232
1233     if (nh->is_group) {
1234         struct nh_group *nhg;
1235         int i;
1236
1237         nhg = rcu_dereference_rtnl(nh->nh_grp);
1238         for (i = 0; i < nhg->num_nh; i++) {
1239             struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1240
1241             nhi = rcu_dereference_rtnl(nhge->nh->nh_info);
1242             err = cb(&nhi->fib6_nh, arg);
1243             if (err)
1244                 return err;
1245         }
1246     } else {
1247         nhi = rcu_dereference_rtnl(nh->nh_info);
1248         err = cb(&nhi->fib6_nh, arg);
1249         if (err)
1250             return err;
1251     }
1252
1253     return 0;
1254 }
1255 EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh);
1256
1257 static int check_src_addr(const struct in6_addr *saddr,
1258               struct netlink_ext_ack *extack)
1259 {
1260     if (!ipv6_addr_any(saddr)) {
1261         NL_SET_ERR_MSG(extack, "IPv6 routes using source address can not use nexthop objects");
1262         return -EINVAL;
1263     }
1264     return 0;
1265 }
1266
1267 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
1268                struct netlink_ext_ack *extack)
1269 {
1270     struct nh_info *nhi;
1271     bool is_fdb_nh;
1272
1273     /* fib6_src is unique to a fib6_info and limits the ability to cache
1274      * routes in fib6_nh within a nexthop that is potentially shared
1275      * across multiple fib entries. If the config wants to use source
1276      * routing it can not use nexthop objects. mlxsw also does not allow
1277      * fib6_src on routes.
1278      */
1279     if (cfg && check_src_addr(&cfg->fc_src, extack) < 0)
1280         return -EINVAL;
1281
1282     if (nh->is_group) {
1283         struct nh_group *nhg;
1284
1285         nhg = rtnl_dereference(nh->nh_grp);
1286         if (nhg->has_v4)
1287             goto no_v4_nh;
1288         is_fdb_nh = nhg->fdb_nh;
1289     } else {
1290         nhi = rtnl_dereference(nh->nh_info);
1291         if (nhi->family == AF_INET)
1292             goto no_v4_nh;
1293         is_fdb_nh = nhi->fdb_nh;
1294     }
1295
1296     if (is_fdb_nh) {
1297         NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1298         return -EINVAL;
1299     }
1300
1301     return 0;
1302 no_v4_nh:
1303     NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop");
1304     return -EINVAL;
1305 }
1306 EXPORT_SYMBOL_GPL(fib6_check_nexthop);
1307
1308 /* if existing nexthop has ipv6 routes linked to it, need
1309  * to verify this new spec works with ipv6
1310  */
1311 static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new,
1312                   struct netlink_ext_ack *extack)
1313 {
1314     struct fib6_info *f6i;
1315
1316     if (list_empty(&old->f6i_list))
1317         return 0;
1318
1319     list_for_each_entry(f6i, &old->f6i_list, nh_list) {
1320         if (check_src_addr(&f6i->fib6_src.addr, extack) < 0)
1321             return -EINVAL;
1322     }
1323
1324     return fib6_check_nexthop(new, NULL, extack);
1325 }
1326
1327 static int nexthop_check_scope(struct nh_info *nhi, u8 scope,
1328                    struct netlink_ext_ack *extack)
1329 {
1330     if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {
1331         NL_SET_ERR_MSG(extack,
1332                    "Route with host scope can not have a gateway");
1333         return -EINVAL;
1334     }
1335
1336     if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {
1337         NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");
1338         return -EINVAL;
1339     }
1340
1341     return 0;
1342 }
1343
1344 /* Invoked by fib add code to verify nexthop by id is ok with
1345  * config for prefix; parts of fib_check_nh not done when nexthop
1346  * object is used.
1347  */
1348 int fib_check_nexthop(struct nexthop *nh, u8 scope,
1349               struct netlink_ext_ack *extack)
1350 {
1351     struct nh_info *nhi;
1352     int err = 0;
1353
1354     if (nh->is_group) {
1355         struct nh_group *nhg;
1356
1357         nhg = rtnl_dereference(nh->nh_grp);
1358         if (nhg->fdb_nh) {
1359             NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1360             err = -EINVAL;
1361             goto out;
1362         }
1363
1364         if (scope == RT_SCOPE_HOST) {
1365             NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");
1366             err = -EINVAL;
1367             goto out;
1368         }
1369
1370         /* all nexthops in a group have the same scope */
1371         nhi = rtnl_dereference(nhg->nh_entries[0].nh->nh_info);
1372         err = nexthop_check_scope(nhi, scope, extack);
1373     } else {
1374         nhi = rtnl_dereference(nh->nh_info);
1375         if (nhi->fdb_nh) {
1376             NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
1377             err = -EINVAL;
1378             goto out;
1379         }
1380         err = nexthop_check_scope(nhi, scope, extack);
1381     }
1382
1383 out:
1384     return err;
1385 }
1386
1387 static int fib_check_nh_list(struct nexthop *old, struct nexthop *new,
1388                  struct netlink_ext_ack *extack)
1389 {
1390     struct fib_info *fi;
1391
1392     list_for_each_entry(fi, &old->fi_list, nh_list) {
1393         int err;
1394
1395         err = fib_check_nexthop(new, fi->fib_scope, extack);
1396         if (err)
1397             return err;
1398     }
1399     return 0;
1400 }
1401
1402 static bool nh_res_nhge_is_balanced(const struct nh_grp_entry *nhge)
1403 {
1404     return nhge->res.count_buckets == nhge->res.wants_buckets;
1405 }
1406
1407 static bool nh_res_nhge_is_ow(const struct nh_grp_entry *nhge)
1408 {
1409     return nhge->res.count_buckets > nhge->res.wants_buckets;
1410 }
1411
1412 static bool nh_res_nhge_is_uw(const struct nh_grp_entry *nhge)
1413 {
1414     return nhge->res.count_buckets < nhge->res.wants_buckets;
1415 }
1416
1417 static bool nh_res_table_is_balanced(const struct nh_res_table *res_table)
1418 {
1419     return list_empty(&res_table->uw_nh_entries);
1420 }
1421
1422 static void nh_res_bucket_unset_nh(struct nh_res_bucket *bucket)
1423 {
1424     struct nh_grp_entry *nhge;
1425
1426     if (bucket->occupied) {
1427         nhge = nh_res_dereference(bucket->nh_entry);
1428         nhge->res.count_buckets--;
1429         bucket->occupied = false;
1430     }
1431 }
1432
1433 static void nh_res_bucket_set_nh(struct nh_res_bucket *bucket,
1434                  struct nh_grp_entry *nhge)
1435 {
1436     nh_res_bucket_unset_nh(bucket);
1437
1438     bucket->occupied = true;
1439     rcu_assign_pointer(bucket->nh_entry, nhge);
1440     nhge->res.count_buckets++;
1441 }
1442
1443 static bool nh_res_bucket_should_migrate(struct nh_res_table *res_table,
1444                      struct nh_res_bucket *bucket,
1445                      unsigned long *deadline, bool *force)
1446 {
1447     unsigned long now = jiffies;
1448     struct nh_grp_entry *nhge;
1449     unsigned long idle_point;
1450
1451     if (!bucket->occupied) {
1452         /* The bucket is not occupied, its NHGE pointer is either
1453          * NULL or obsolete. We _have to_ migrate: set force.
1454          */
1455         *force = true;
1456         return true;
1457     }
1458
1459     nhge = nh_res_dereference(bucket->nh_entry);
1460
1461     /* If the bucket is populated by an underweight or balanced
1462      * nexthop, do not migrate.
1463      */
1464     if (!nh_res_nhge_is_ow(nhge))
1465         return false;
1466
1467     /* At this point we know that the bucket is populated with an
1468      * overweight nexthop. It needs to be migrated to a new nexthop if
1469      * the idle timer of unbalanced timer expired.
1470      */
1471
1472     idle_point = nh_res_bucket_idle_point(res_table, bucket, now);
1473     if (time_after_eq(now, idle_point)) {
1474         /* The bucket is idle. We _can_ migrate: unset force. */
1475         *force = false;
1476         return true;
1477     }
1478
1479     /* Unbalanced timer of 0 means "never force". */
1480     if (res_table->unbalanced_timer) {
1481         unsigned long unb_point;
1482
1483         unb_point = nh_res_table_unb_point(res_table);
1484         if (time_after(now, unb_point)) {
1485             /* The bucket is not idle, but the unbalanced timer
1486              * expired. We _can_ migrate, but set force anyway,
1487              * so that drivers know to ignore activity reports
1488              * from the HW.
1489              */
1490             *force = true;
1491             return true;
1492         }
1493
1494         nh_res_time_set_deadline(unb_point, deadline);
1495     }
1496
1497     nh_res_time_set_deadline(idle_point, deadline);
1498     return false;
1499 }
1500
1501 static bool nh_res_bucket_migrate(struct nh_res_table *res_table,
1502                   u16 bucket_index, bool notify,
1503                   bool notify_nl, bool force)
1504 {
1505     struct nh_res_bucket *bucket = &res_table->nh_buckets[bucket_index];
1506     struct nh_grp_entry *new_nhge;
1507     struct netlink_ext_ack extack;
1508     int err;
1509
1510     new_nhge = list_first_entry_or_null(&res_table->uw_nh_entries,
1511                         struct nh_grp_entry,
1512                         res.uw_nh_entry);
1513     if (WARN_ON_ONCE(!new_nhge))
1514         /* If this function is called, "bucket" is either not
1515          * occupied, or it belongs to a next hop that is
1516          * overweight. In either case, there ought to be a
1517          * corresponding underweight next hop.
1518          */
1519         return false;
1520
1521     if (notify) {
1522         struct nh_grp_entry *old_nhge;
1523
1524         old_nhge = nh_res_dereference(bucket->nh_entry);
1525         err = call_nexthop_res_bucket_notifiers(res_table->net,
1526                             res_table->nhg_id,
1527                             bucket_index, force,
1528                             old_nhge->nh,
1529                             new_nhge->nh, &extack);
1530         if (err) {
1531             pr_err_ratelimited("%s\n", extack._msg);
1532             if (!force)
1533                 return false;
1534             /* It is not possible to veto a forced replacement, so
1535              * just clear the hardware flags from the nexthop
1536              * bucket to indicate to user space that this bucket is
1537              * not correctly populated in hardware.
1538              */
1539             bucket->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
1540         }
1541     }
1542
1543     nh_res_bucket_set_nh(bucket, new_nhge);
1544     nh_res_bucket_set_idle(res_table, bucket);
1545
1546     if (notify_nl)
1547         nexthop_bucket_notify(res_table, bucket_index);
1548
1549     if (nh_res_nhge_is_balanced(new_nhge))
1550         list_del(&new_nhge->res.uw_nh_entry);
1551     return true;
1552 }
1553
1554 #define NH_RES_UPKEEP_DW_MINIMUM_INTERVAL (HZ / 2)
1555
1556 static void nh_res_table_upkeep(struct nh_res_table *res_table,
1557                 bool notify, bool notify_nl)
1558 {
1559     unsigned long now = jiffies;
1560     unsigned long deadline;
1561     u16 i;
1562
1563     /* Deadline is the next time that upkeep should be run. It is the
1564      * earliest time at which one of the buckets might be migrated.
1565      * Start at the most pessimistic estimate: either unbalanced_timer
1566      * from now, or if there is none, idle_timer from now. For each
1567      * encountered time point, call nh_res_time_set_deadline() to
1568      * refine the estimate.
1569      */
1570     if (res_table->unbalanced_timer)
1571         deadline = now + res_table->unbalanced_timer;
1572     else
1573         deadline = now + res_table->idle_timer;
1574
1575     for (i = 0; i < res_table->num_nh_buckets; i++) {
1576         struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
1577         bool force;
1578
1579         if (nh_res_bucket_should_migrate(res_table, bucket,
1580                          &deadline, &force)) {
1581             if (!nh_res_bucket_migrate(res_table, i, notify,
1582                            notify_nl, force)) {
1583                 unsigned long idle_point;
1584
1585                 /* A driver can override the migration
1586                  * decision if the HW reports that the
1587                  * bucket is actually not idle. Therefore
1588                  * remark the bucket as busy again and
1589                  * update the deadline.
1590                  */
1591                 nh_res_bucket_set_busy(bucket);
1592                 idle_point = nh_res_bucket_idle_point(res_table,
1593                                       bucket,
1594                                       now);
1595                 nh_res_time_set_deadline(idle_point, &deadline);
1596             }
1597         }
1598     }
1599
1600     /* If the group is still unbalanced, schedule the next upkeep to
1601      * either the deadline computed above, or the minimum deadline,
1602      * whichever comes later.
1603      */
1604     if (!nh_res_table_is_balanced(res_table)) {
1605         unsigned long now = jiffies;
1606         unsigned long min_deadline;
1607
1608         min_deadline = now + NH_RES_UPKEEP_DW_MINIMUM_INTERVAL;
1609         if (time_before(deadline, min_deadline))
1610             deadline = min_deadline;
1611
1612         queue_delayed_work(system_power_efficient_wq,
1613                    &res_table->upkeep_dw, deadline - now);
1614     }
1615 }
1616
1617 static void nh_res_table_upkeep_dw(struct work_struct *work)
1618 {
1619     struct delayed_work *dw = to_delayed_work(work);
1620     struct nh_res_table *res_table;
1621
1622     res_table = container_of(dw, struct nh_res_table, upkeep_dw);
1623     nh_res_table_upkeep(res_table, true, true);
1624 }
1625
1626 static void nh_res_table_cancel_upkeep(struct nh_res_table *res_table)
1627 {
1628     cancel_delayed_work_sync(&res_table->upkeep_dw);
1629 }
1630
1631 static void nh_res_group_rebalance(struct nh_group *nhg,
1632                    struct nh_res_table *res_table)
1633 {
1634     int prev_upper_bound = 0;
1635     int total = 0;
1636     int w = 0;
1637     int i;
1638
1639     INIT_LIST_HEAD(&res_table->uw_nh_entries);
1640
1641     for (i = 0; i < nhg->num_nh; ++i)
1642         total += nhg->nh_entries[i].weight;
1643
1644     for (i = 0; i < nhg->num_nh; ++i) {
1645         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1646         int upper_bound;
1647
1648         w += nhge->weight;
1649         upper_bound = DIV_ROUND_CLOSEST(res_table->num_nh_buckets * w,
1650                         total);
1651         nhge->res.wants_buckets = upper_bound - prev_upper_bound;
1652         prev_upper_bound = upper_bound;
1653
1654         if (nh_res_nhge_is_uw(nhge)) {
1655             if (list_empty(&res_table->uw_nh_entries))
1656                 res_table->unbalanced_since = jiffies;
1657             list_add(&nhge->res.uw_nh_entry,
1658                  &res_table->uw_nh_entries);
1659         }
1660     }
1661 }
1662
1663 /* Migrate buckets in res_table so that they reference NHGE's from NHG with
1664  * the right NH ID. Set those buckets that do not have a corresponding NHGE
1665  * entry in NHG as not occupied.
1666  */
1667 static void nh_res_table_migrate_buckets(struct nh_res_table *res_table,
1668                      struct nh_group *nhg)
1669 {
1670     u16 i;
1671
1672     for (i = 0; i < res_table->num_nh_buckets; i++) {
1673         struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
1674         u32 id = rtnl_dereference(bucket->nh_entry)->nh->id;
1675         bool found = false;
1676         int j;
1677
1678         for (j = 0; j < nhg->num_nh; j++) {
1679             struct nh_grp_entry *nhge = &nhg->nh_entries[j];
1680
1681             if (nhge->nh->id == id) {
1682                 nh_res_bucket_set_nh(bucket, nhge);
1683                 found = true;
1684                 break;
1685             }
1686         }
1687
1688         if (!found)
1689             nh_res_bucket_unset_nh(bucket);
1690     }
1691 }
1692
1693 static void replace_nexthop_grp_res(struct nh_group *oldg,
1694                     struct nh_group *newg)
1695 {
1696     /* For NH group replacement, the new NHG might only have a stub
1697      * hash table with 0 buckets, because the number of buckets was not
1698      * specified. For NH removal, oldg and newg both reference the same
1699      * res_table. So in any case, in the following, we want to work
1700      * with oldg->res_table.
1701      */
1702     struct nh_res_table *old_res_table = rtnl_dereference(oldg->res_table);
1703     unsigned long prev_unbalanced_since = old_res_table->unbalanced_since;
1704     bool prev_has_uw = !list_empty(&old_res_table->uw_nh_entries);
1705
1706     nh_res_table_cancel_upkeep(old_res_table);
1707     nh_res_table_migrate_buckets(old_res_table, newg);
1708     nh_res_group_rebalance(newg, old_res_table);
1709     if (prev_has_uw && !list_empty(&old_res_table->uw_nh_entries))
1710         old_res_table->unbalanced_since = prev_unbalanced_since;
1711     nh_res_table_upkeep(old_res_table, true, false);
1712 }
1713
1714 static void nh_hthr_group_rebalance(struct nh_group *nhg)
1715 {
1716     int total = 0;
1717     int w = 0;
1718     int i;
1719
1720     for (i = 0; i < nhg->num_nh; ++i)
1721         total += nhg->nh_entries[i].weight;
1722
1723     for (i = 0; i < nhg->num_nh; ++i) {
1724         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1725         int upper_bound;
1726
1727         w += nhge->weight;
1728         upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1;
1729         atomic_set(&nhge->hthr.upper_bound, upper_bound);
1730     }
1731 }
1732
1733 static void remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge,
1734                 struct nl_info *nlinfo)
1735 {
1736     struct nh_grp_entry *nhges, *new_nhges;
1737     struct nexthop *nhp = nhge->nh_parent;
1738     struct netlink_ext_ack extack;
1739     struct nexthop *nh = nhge->nh;
1740     struct nh_group *nhg, *newg;
1741     int i, j, err;
1742
1743     WARN_ON(!nh);
1744
1745     nhg = rtnl_dereference(nhp->nh_grp);
1746     newg = nhg->spare;
1747
1748     /* last entry, keep it visible and remove the parent */
1749     if (nhg->num_nh == 1) {
1750         remove_nexthop(net, nhp, nlinfo);
1751         return;
1752     }
1753
1754     newg->has_v4 = false;
1755     newg->is_multipath = nhg->is_multipath;
1756     newg->hash_threshold = nhg->hash_threshold;
1757     newg->resilient = nhg->resilient;
1758     newg->fdb_nh = nhg->fdb_nh;
1759     newg->num_nh = nhg->num_nh;
1760
1761     /* copy old entries to new except the one getting removed */
1762     nhges = nhg->nh_entries;
1763     new_nhges = newg->nh_entries;
1764     for (i = 0, j = 0; i < nhg->num_nh; ++i) {
1765         struct nh_info *nhi;
1766
1767         /* current nexthop getting removed */
1768         if (nhg->nh_entries[i].nh == nh) {
1769             newg->num_nh--;
1770             continue;
1771         }
1772
1773         nhi = rtnl_dereference(nhges[i].nh->nh_info);
1774         if (nhi->family == AF_INET)
1775             newg->has_v4 = true;
1776
1777         list_del(&nhges[i].nh_list);
1778         new_nhges[j].nh_parent = nhges[i].nh_parent;
1779         new_nhges[j].nh = nhges[i].nh;
1780         new_nhges[j].weight = nhges[i].weight;
1781         list_add(&new_nhges[j].nh_list, &new_nhges[j].nh->grp_list);
1782         j++;
1783     }
1784
1785     if (newg->hash_threshold)
1786         nh_hthr_group_rebalance(newg);
1787     else if (newg->resilient)
1788         replace_nexthop_grp_res(nhg, newg);
1789
1790     rcu_assign_pointer(nhp->nh_grp, newg);
1791
1792     list_del(&nhge->nh_list);
1793     nexthop_put(nhge->nh);
1794
1795     /* Removal of a NH from a resilient group is notified through
1796      * bucket notifications.
1797      */
1798     if (newg->hash_threshold) {
1799         err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, nhp,
1800                          &extack);
1801         if (err)
1802             pr_err("%s\n", extack._msg);
1803     }
1804
1805     if (nlinfo)
1806         nexthop_notify(RTM_NEWNEXTHOP, nhp, nlinfo);
1807 }
1808
1809 static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh,
1810                        struct nl_info *nlinfo)
1811 {
1812     struct nh_grp_entry *nhge, *tmp;
1813
1814     list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list)
1815         remove_nh_grp_entry(net, nhge, nlinfo);
1816
1817     /* make sure all see the newly published array before releasing rtnl */
1818     synchronize_net();
1819 }
1820
1821 static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo)
1822 {
1823     struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
1824     struct nh_res_table *res_table;
1825     int i, num_nh = nhg->num_nh;
1826
1827     for (i = 0; i < num_nh; ++i) {
1828         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1829
1830         if (WARN_ON(!nhge->nh))
1831             continue;
1832
1833         list_del_init(&nhge->nh_list);
1834     }
1835
1836     if (nhg->resilient) {
1837         res_table = rtnl_dereference(nhg->res_table);
1838         nh_res_table_cancel_upkeep(res_table);
1839     }
1840 }
1841
1842 /* not called for nexthop replace */
1843 static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
1844 {
1845     struct fib6_info *f6i, *tmp;
1846     bool do_flush = false;
1847     struct fib_info *fi;
1848
1849     list_for_each_entry(fi, &nh->fi_list, nh_list) {
1850         fi->fib_flags |= RTNH_F_DEAD;
1851         do_flush = true;
1852     }
1853     if (do_flush)
1854         fib_flush(net);
1855
1856     /* ip6_del_rt removes the entry from this list hence the _safe */
1857     list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) {
1858         /* __ip6_del_rt does a release, so do a hold here */
1859         fib6_info_hold(f6i);
1860         ipv6_stub->ip6_del_rt(net, f6i,
1861                       !READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
1862     }
1863 }
1864
1865 static void __remove_nexthop(struct net *net, struct nexthop *nh,
1866                  struct nl_info *nlinfo)
1867 {
1868     __remove_nexthop_fib(net, nh);
1869
1870     if (nh->is_group) {
1871         remove_nexthop_group(nh, nlinfo);
1872     } else {
1873         struct nh_info *nhi;
1874
1875         nhi = rtnl_dereference(nh->nh_info);
1876         if (nhi->fib_nhc.nhc_dev)
1877             hlist_del(&nhi->dev_hash);
1878
1879         remove_nexthop_from_groups(net, nh, nlinfo);
1880     }
1881 }
1882
1883 static void remove_nexthop(struct net *net, struct nexthop *nh,
1884                struct nl_info *nlinfo)
1885 {
1886     call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh, NULL);
1887
1888     /* remove from the tree */
1889     rb_erase(&nh->rb_node, &net->nexthop.rb_root);
1890
1891     if (nlinfo)
1892         nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
1893
1894     __remove_nexthop(net, nh, nlinfo);
1895     nh_base_seq_inc(net);
1896
1897     nexthop_put(nh);
1898 }
1899
1900 /* if any FIB entries reference this nexthop, any dst entries
1901  * need to be regenerated
1902  */
1903 static void nh_rt_cache_flush(struct net *net, struct nexthop *nh,
1904                   struct nexthop *replaced_nh)
1905 {
1906     struct fib6_info *f6i;
1907     struct nh_group *nhg;
1908     int i;
1909
1910     if (!list_empty(&nh->fi_list))
1911         rt_cache_flush(net);
1912
1913     list_for_each_entry(f6i, &nh->f6i_list, nh_list)
1914         ipv6_stub->fib6_update_sernum(net, f6i);
1915
1916     /* if an IPv6 group was replaced, we have to release all old
1917      * dsts to make sure all refcounts are released
1918      */
1919     if (!replaced_nh->is_group)
1920         return;
1921
1922     nhg = rtnl_dereference(replaced_nh->nh_grp);
1923     for (i = 0; i < nhg->num_nh; i++) {
1924         struct nh_grp_entry *nhge = &nhg->nh_entries[i];
1925         struct nh_info *nhi = rtnl_dereference(nhge->nh->nh_info);
1926
1927         if (nhi->family == AF_INET6)
1928             ipv6_stub->fib6_nh_release_dsts(&nhi->fib6_nh);
1929     }
1930 }
1931
1932 static int replace_nexthop_grp(struct net *net, struct nexthop *old,
1933                    struct nexthop *new, const struct nh_config *cfg,
1934                    struct netlink_ext_ack *extack)
1935 {
1936     struct nh_res_table *tmp_table = NULL;
1937     struct nh_res_table *new_res_table;
1938     struct nh_res_table *old_res_table;
1939     struct nh_group *oldg, *newg;
1940     int i, err;
1941
1942     if (!new->is_group) {
1943         NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a nexthop.");
1944         return -EINVAL;
1945     }
1946
1947     oldg = rtnl_dereference(old->nh_grp);
1948     newg = rtnl_dereference(new->nh_grp);
1949
1950     if (newg->hash_threshold != oldg->hash_threshold) {
1951         NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with one of a different type.");
1952         return -EINVAL;
1953     }
1954
1955     if (newg->hash_threshold) {
1956         err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new,
1957                          extack);
1958         if (err)
1959             return err;
1960     } else if (newg->resilient) {
1961         new_res_table = rtnl_dereference(newg->res_table);
1962         old_res_table = rtnl_dereference(oldg->res_table);
1963
1964         /* Accept if num_nh_buckets was not given, but if it was
1965          * given, demand that the value be correct.
1966          */
1967         if (cfg->nh_grp_res_has_num_buckets &&
1968             cfg->nh_grp_res_num_buckets !=
1969             old_res_table->num_nh_buckets) {
1970             NL_SET_ERR_MSG(extack, "Can not change number of buckets of a resilient nexthop group.");
1971             return -EINVAL;
1972         }
1973
1974         /* Emit a pre-replace notification so that listeners could veto
1975          * a potentially unsupported configuration. Otherwise,
1976          * individual bucket replacement notifications would need to be
1977          * vetoed, which is something that should only happen if the
1978          * bucket is currently active.
1979          */
1980         err = call_nexthop_res_table_notifiers(net, new, extack);
1981         if (err)
1982             return err;
1983
1984         if (cfg->nh_grp_res_has_idle_timer)
1985             old_res_table->idle_timer = cfg->nh_grp_res_idle_timer;
1986         if (cfg->nh_grp_res_has_unbalanced_timer)
1987             old_res_table->unbalanced_timer =
1988                 cfg->nh_grp_res_unbalanced_timer;
1989
1990         replace_nexthop_grp_res(oldg, newg);
1991
1992         tmp_table = new_res_table;
1993         rcu_assign_pointer(newg->res_table, old_res_table);
1994         rcu_assign_pointer(newg->spare->res_table, old_res_table);
1995     }
1996
1997     /* update parents - used by nexthop code for cleanup */
1998     for (i = 0; i < newg->num_nh; i++)
1999         newg->nh_entries[i].nh_parent = old;
2000
2001     rcu_assign_pointer(old->nh_grp, newg);
2002
2003     /* Make sure concurrent readers are not using 'oldg' anymore. */
2004     synchronize_net();
2005
2006     if (newg->resilient) {
2007         rcu_assign_pointer(oldg->res_table, tmp_table);
2008         rcu_assign_pointer(oldg->spare->res_table, tmp_table);
2009     }
2010
2011     for (i = 0; i < oldg->num_nh; i++)
2012         oldg->nh_entries[i].nh_parent = new;
2013
2014     rcu_assign_pointer(new->nh_grp, oldg);
2015
2016     return 0;
2017 }
2018
2019 static void nh_group_v4_update(struct nh_group *nhg)
2020 {
2021     struct nh_grp_entry *nhges;
2022     bool has_v4 = false;
2023     int i;
2024
2025     nhges = nhg->nh_entries;
2026     for (i = 0; i < nhg->num_nh; i++) {
2027         struct nh_info *nhi;
2028
2029         nhi = rtnl_dereference(nhges[i].nh->nh_info);
2030         if (nhi->family == AF_INET)
2031             has_v4 = true;
2032     }
2033     nhg->has_v4 = has_v4;
2034 }
2035
2036 static int replace_nexthop_single_notify_res(struct net *net,
2037                          struct nh_res_table *res_table,
2038                          struct nexthop *old,
2039                          struct nh_info *oldi,
2040                          struct nh_info *newi,
2041                          struct netlink_ext_ack *extack)
2042 {
2043     u32 nhg_id = res_table->nhg_id;
2044     int err;
2045     u16 i;
2046
2047     for (i = 0; i < res_table->num_nh_buckets; i++) {
2048         struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
2049         struct nh_grp_entry *nhge;
2050
2051         nhge = rtnl_dereference(bucket->nh_entry);
2052         if (nhge->nh == old) {
2053             err = __call_nexthop_res_bucket_notifiers(net, nhg_id,
2054                                   i, true,
2055                                   oldi, newi,
2056                                   extack);
2057             if (err)
2058                 goto err_notify;
2059         }
2060     }
2061
2062     return 0;
2063
2064 err_notify:
2065     while (i-- > 0) {
2066         struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
2067         struct nh_grp_entry *nhge;
2068
2069         nhge = rtnl_dereference(bucket->nh_entry);
2070         if (nhge->nh == old)
2071             __call_nexthop_res_bucket_notifiers(net, nhg_id, i,
2072                                 true, newi, oldi,
2073                                 extack);
2074     }
2075     return err;
2076 }
2077
2078 static int replace_nexthop_single_notify(struct net *net,
2079                      struct nexthop *group_nh,
2080                      struct nexthop *old,
2081                      struct nh_info *oldi,
2082                      struct nh_info *newi,
2083                      struct netlink_ext_ack *extack)
2084 {
2085     struct nh_group *nhg = rtnl_dereference(group_nh->nh_grp);
2086     struct nh_res_table *res_table;
2087
2088     if (nhg->hash_threshold) {
2089         return call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE,
2090                           group_nh, extack);
2091     } else if (nhg->resilient) {
2092         res_table = rtnl_dereference(nhg->res_table);
2093         return replace_nexthop_single_notify_res(net, res_table,
2094                              old, oldi, newi,
2095                              extack);
2096     }
2097
2098     return -EINVAL;
2099 }
2100
2101 static int replace_nexthop_single(struct net *net, struct nexthop *old,
2102                   struct nexthop *new,
2103                   struct netlink_ext_ack *extack)
2104 {
2105     u8 old_protocol, old_nh_flags;
2106     struct nh_info *oldi, *newi;
2107     struct nh_grp_entry *nhge;
2108     int err;
2109
2110     if (new->is_group) {
2111         NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a nexthop group.");
2112         return -EINVAL;
2113     }
2114
2115     err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new, extack);
2116     if (err)
2117         return err;
2118
2119     /* Hardware flags were set on 'old' as 'new' is not in the red-black
2120      * tree. Therefore, inherit the flags from 'old' to 'new'.
2121      */
2122     new->nh_flags |= old->nh_flags & (RTNH_F_OFFLOAD | RTNH_F_TRAP);
2123
2124     oldi = rtnl_dereference(old->nh_info);
2125     newi = rtnl_dereference(new->nh_info);
2126
2127     newi->nh_parent = old;
2128     oldi->nh_parent = new;
2129
2130     old_protocol = old->protocol;
2131     old_nh_flags = old->nh_flags;
2132
2133     old->protocol = new->protocol;
2134     old->nh_flags = new->nh_flags;
2135
2136     rcu_assign_pointer(old->nh_info, newi);
2137     rcu_assign_pointer(new->nh_info, oldi);
2138
2139     /* Send a replace notification for all the groups using the nexthop. */
2140     list_for_each_entry(nhge, &old->grp_list, nh_list) {
2141         struct nexthop *nhp = nhge->nh_parent;
2142
2143         err = replace_nexthop_single_notify(net, nhp, old, oldi, newi,
2144                             extack);
2145         if (err)
2146             goto err_notify;
2147     }
2148
2149     /* When replacing an IPv4 nexthop with an IPv6 nexthop, potentially
2150      * update IPv4 indication in all the groups using the nexthop.
2151      */
2152     if (oldi->family == AF_INET && newi->family == AF_INET6) {
2153         list_for_each_entry(nhge, &old->grp_list, nh_list) {
2154             struct nexthop *nhp = nhge->nh_parent;
2155             struct nh_group *nhg;
2156
2157             nhg = rtnl_dereference(nhp->nh_grp);
2158             nh_group_v4_update(nhg);
2159         }
2160     }
2161
2162     return 0;
2163
2164 err_notify:
2165     rcu_assign_pointer(new->nh_info, newi);
2166     rcu_assign_pointer(old->nh_info, oldi);
2167     old->nh_flags = old_nh_flags;
2168     old->protocol = old_protocol;
2169     oldi->nh_parent = old;
2170     newi->nh_parent = new;
2171     list_for_each_entry_continue_reverse(nhge, &old->grp_list, nh_list) {
2172         struct nexthop *nhp = nhge->nh_parent;
2173
2174         replace_nexthop_single_notify(net, nhp, old, newi, oldi, NULL);
2175     }
2176     call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, old, extack);
2177     return err;
2178 }
2179
2180 static void __nexthop_replace_notify(struct net *net, struct nexthop *nh,
2181                      struct nl_info *info)
2182 {
2183     struct fib6_info *f6i;
2184
2185     if (!list_empty(&nh->fi_list)) {
2186         struct fib_info *fi;
2187
2188         /* expectation is a few fib_info per nexthop and then
2189          * a lot of routes per fib_info. So mark the fib_info
2190          * and then walk the fib tables once
2191          */
2192         list_for_each_entry(fi, &nh->fi_list, nh_list)
2193             fi->nh_updated = true;
2194
2195         fib_info_notify_update(net, info);
2196
2197         list_for_each_entry(fi, &nh->fi_list, nh_list)
2198             fi->nh_updated = false;
2199     }
2200
2201     list_for_each_entry(f6i, &nh->f6i_list, nh_list)
2202         ipv6_stub->fib6_rt_update(net, f6i, info);
2203 }
2204
2205 /* send RTM_NEWROUTE with REPLACE flag set for all FIB entries
2206  * linked to this nexthop and for all groups that the nexthop
2207  * is a member of
2208  */
2209 static void nexthop_replace_notify(struct net *net, struct nexthop *nh,
2210                    struct nl_info *info)
2211 {
2212     struct nh_grp_entry *nhge;
2213
2214     __nexthop_replace_notify(net, nh, info);
2215
2216     list_for_each_entry(nhge, &nh->grp_list, nh_list)
2217         __nexthop_replace_notify(net, nhge->nh_parent, info);
2218 }
2219
2220 static int replace_nexthop(struct net *net, struct nexthop *old,
2221                struct nexthop *new, const struct nh_config *cfg,
2222                struct netlink_ext_ack *extack)
2223 {
2224     bool new_is_reject = false;
2225     struct nh_grp_entry *nhge;
2226     int err;
2227
2228     /* check that existing FIB entries are ok with the
2229      * new nexthop definition
2230      */
2231     err = fib_check_nh_list(old, new, extack);
2232     if (err)
2233         return err;
2234
2235     err = fib6_check_nh_list(old, new, extack);
2236     if (err)
2237         return err;
2238
2239     if (!new->is_group) {
2240         struct nh_info *nhi = rtnl_dereference(new->nh_info);
2241
2242         new_is_reject = nhi->reject_nh;
2243     }
2244
2245     list_for_each_entry(nhge, &old->grp_list, nh_list) {
2246         /* if new nexthop is a blackhole, any groups using this
2247          * nexthop cannot have more than 1 path
2248          */
2249         if (new_is_reject &&
2250             nexthop_num_path(nhge->nh_parent) > 1) {
2251             NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a member of a group with more than one path");
2252             return -EINVAL;
2253         }
2254
2255         err = fib_check_nh_list(nhge->nh_parent, new, extack);
2256         if (err)
2257             return err;
2258
2259         err = fib6_check_nh_list(nhge->nh_parent, new, extack);
2260         if (err)
2261             return err;
2262     }
2263
2264     if (old->is_group)
2265         err = replace_nexthop_grp(net, old, new, cfg, extack);
2266     else
2267         err = replace_nexthop_single(net, old, new, extack);
2268
2269     if (!err) {
2270         nh_rt_cache_flush(net, old, new);
2271
2272         __remove_nexthop(net, new, NULL);
2273         nexthop_put(new);
2274     }
2275
2276     return err;
2277 }
2278
2279 /* called with rtnl_lock held */
2280 static int insert_nexthop(struct net *net, struct nexthop *new_nh,
2281               struct nh_config *cfg, struct netlink_ext_ack *extack)
2282 {
2283     struct rb_node **pp, *parent = NULL, *next;
2284     struct rb_root *root = &net->nexthop.rb_root;
2285     bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
2286     bool create = !!(cfg->nlflags & NLM_F_CREATE);
2287     u32 new_id = new_nh->id;
2288     int replace_notify = 0;
2289     int rc = -EEXIST;
2290
2291     pp = &root->rb_node;
2292     while (1) {
2293         struct nexthop *nh;
2294
2295         next = *pp;
2296         if (!next)
2297             break;
2298
2299         parent = next;
2300
2301         nh = rb_entry(parent, struct nexthop, rb_node);
2302         if (new_id < nh->id) {
2303             pp = &next->rb_left;
2304         } else if (new_id > nh->id) {
2305             pp = &next->rb_right;
2306         } else if (replace) {
2307             rc = replace_nexthop(net, nh, new_nh, cfg, extack);
2308             if (!rc) {
2309                 new_nh = nh; /* send notification with old nh */
2310                 replace_notify = 1;
2311             }
2312             goto out;
2313         } else {
2314             /* id already exists and not a replace */
2315             goto out;
2316         }
2317     }
2318
2319     if (replace && !create) {
2320         NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists");
2321         rc = -ENOENT;
2322         goto out;
2323     }
2324
2325     if (new_nh->is_group) {
2326         struct nh_group *nhg = rtnl_dereference(new_nh->nh_grp);
2327         struct nh_res_table *res_table;
2328
2329         if (nhg->resilient) {
2330             res_table = rtnl_dereference(nhg->res_table);
2331
2332             /* Not passing the number of buckets is OK when
2333              * replacing, but not when creating a new group.
2334              */
2335             if (!cfg->nh_grp_res_has_num_buckets) {
2336                 NL_SET_ERR_MSG(extack, "Number of buckets not specified for nexthop group insertion");
2337                 rc = -EINVAL;
2338                 goto out;
2339             }
2340
2341             nh_res_group_rebalance(nhg, res_table);
2342
2343             /* Do not send bucket notifications, we do full
2344              * notification below.
2345              */
2346             nh_res_table_upkeep(res_table, false, false);
2347         }
2348     }
2349
2350     rb_link_node_rcu(&new_nh->rb_node, parent, pp);
2351     rb_insert_color(&new_nh->rb_node, root);
2352
2353     /* The initial insertion is a full notification for hash-threshold as
2354      * well as resilient groups.
2355      */
2356     rc = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new_nh, extack);
2357     if (rc)
2358         rb_erase(&new_nh->rb_node, &net->nexthop.rb_root);
2359
2360 out:
2361     if (!rc) {
2362         nh_base_seq_inc(net);
2363         nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
2364         if (replace_notify &&
2365             READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode))
2366             nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
2367     }
2368
2369     return rc;
2370 }
2371
2372 /* rtnl */
2373 /* remove all nexthops tied to a device being deleted */
2374 static void nexthop_flush_dev(struct net_device *dev, unsigned long event)
2375 {
2376     unsigned int hash = nh_dev_hashfn(dev->ifindex);
2377     struct net *net = dev_net(dev);
2378     struct hlist_head *head = &net->nexthop.devhash[hash];
2379     struct hlist_node *n;
2380     struct nh_info *nhi;
2381
2382     hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
2383         if (nhi->fib_nhc.nhc_dev != dev)
2384             continue;
2385
2386         if (nhi->reject_nh &&
2387             (event == NETDEV_DOWN || event == NETDEV_CHANGE))
2388             continue;
2389
2390         remove_nexthop(net, nhi->nh_parent, NULL);
2391     }
2392 }
2393
2394 /* rtnl; called when net namespace is deleted */
2395 static void flush_all_nexthops(struct net *net)
2396 {
2397     struct rb_root *root = &net->nexthop.rb_root;
2398     struct rb_node *node;
2399     struct nexthop *nh;
2400
2401     while ((node = rb_first(root))) {
2402         nh = rb_entry(node, struct nexthop, rb_node);
2403         remove_nexthop(net, nh, NULL);
2404         cond_resched();
2405     }
2406 }
2407
2408 static struct nexthop *nexthop_create_group(struct net *net,
2409                         struct nh_config *cfg)
2410 {
2411     struct nlattr *grps_attr = cfg->nh_grp;
2412     struct nexthop_grp *entry = nla_data(grps_attr);
2413     u16 num_nh = nla_len(grps_attr) / sizeof(*entry);
2414     struct nh_group *nhg;
2415     struct nexthop *nh;
2416     int err;
2417     int i;
2418
2419     if (WARN_ON(!num_nh))
2420         return ERR_PTR(-EINVAL);
2421
2422     nh = nexthop_alloc();
2423     if (!nh)
2424         return ERR_PTR(-ENOMEM);
2425
2426     nh->is_group = 1;
2427
2428     nhg = nexthop_grp_alloc(num_nh);
2429     if (!nhg) {
2430         kfree(nh);
2431         return ERR_PTR(-ENOMEM);
2432     }
2433
2434     /* spare group used for removals */
2435     nhg->spare = nexthop_grp_alloc(num_nh);
2436     if (!nhg->spare) {
2437         kfree(nhg);
2438         kfree(nh);
2439         return ERR_PTR(-ENOMEM);
2440     }
2441     nhg->spare->spare = nhg;
2442
2443     for (i = 0; i < nhg->num_nh; ++i) {
2444         struct nexthop *nhe;
2445         struct nh_info *nhi;
2446
2447         nhe = nexthop_find_by_id(net, entry[i].id);
2448         if (!nexthop_get(nhe)) {
2449             err = -ENOENT;
2450             goto out_no_nh;
2451         }
2452
2453         nhi = rtnl_dereference(nhe->nh_info);
2454         if (nhi->family == AF_INET)
2455             nhg->has_v4 = true;
2456
2457         nhg->nh_entries[i].nh = nhe;
2458         nhg->nh_entries[i].weight = entry[i].weight + 1;
2459         list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list);
2460         nhg->nh_entries[i].nh_parent = nh;
2461     }
2462
2463     if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) {
2464         nhg->hash_threshold = 1;
2465         nhg->is_multipath = true;
2466     } else if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES) {
2467         struct nh_res_table *res_table;
2468
2469         res_table = nexthop_res_table_alloc(net, cfg->nh_id, cfg);
2470         if (!res_table) {
2471             err = -ENOMEM;
2472             goto out_no_nh;
2473         }
2474
2475         rcu_assign_pointer(nhg->spare->res_table, res_table);
2476         rcu_assign_pointer(nhg->res_table, res_table);
2477         nhg->resilient = true;
2478         nhg->is_multipath = true;
2479     }
2480
2481     WARN_ON_ONCE(nhg->hash_threshold + nhg->resilient != 1);
2482
2483     if (nhg->hash_threshold)
2484         nh_hthr_group_rebalance(nhg);
2485
2486     if (cfg->nh_fdb)
2487         nhg->fdb_nh = 1;
2488
2489     rcu_assign_pointer(nh->nh_grp, nhg);
2490
2491     return nh;
2492
2493 out_no_nh:
2494     for (i--; i >= 0; --i) {
2495         list_del(&nhg->nh_entries[i].nh_list);
2496         nexthop_put(nhg->nh_entries[i].nh);
2497     }
2498
2499     kfree(nhg->spare);
2500     kfree(nhg);
2501     kfree(nh);
2502
2503     return ERR_PTR(err);
2504 }
2505
2506 static int nh_create_ipv4(struct net *net, struct nexthop *nh,
2507               struct nh_info *nhi, struct nh_config *cfg,
2508               struct netlink_ext_ack *extack)
2509 {
2510     struct fib_nh *fib_nh = &nhi->fib_nh;
2511     struct fib_config fib_cfg = {
2512         .fc_oif   = cfg->nh_ifindex,
2513         .fc_gw4   = cfg->gw.ipv4,
2514         .fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0,
2515         .fc_flags = cfg->nh_flags,
2516         .fc_nlinfo = cfg->nlinfo,
2517         .fc_encap = cfg->nh_encap,
2518         .fc_encap_type = cfg->nh_encap_type,
2519     };
2520     u32 tb_id = (cfg->dev ? l3mdev_fib_table(cfg->dev) : RT_TABLE_MAIN);
2521     int err;
2522
2523     err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack);
2524     if (err) {
2525         fib_nh_release(net, fib_nh);
2526         goto out;
2527     }
2528
2529     if (nhi->fdb_nh)
2530         goto out;
2531
2532     /* sets nh_dev if successful */
2533     err = fib_check_nh(net, fib_nh, tb_id, 0, extack);
2534     if (!err) {
2535         nh->nh_flags = fib_nh->fib_nh_flags;
2536         fib_info_update_nhc_saddr(net, &fib_nh->nh_common,
2537                       fib_nh->fib_nh_scope);
2538     } else {
2539         fib_nh_release(net, fib_nh);
2540     }
2541 out:
2542     return err;
2543 }
2544
2545 static int nh_create_ipv6(struct net *net,  struct nexthop *nh,
2546               struct nh_info *nhi, struct nh_config *cfg,
2547               struct netlink_ext_ack *extack)
2548 {
2549     struct fib6_nh *fib6_nh = &nhi->fib6_nh;
2550     struct fib6_config fib6_cfg = {
2551         .fc_table = l3mdev_fib_table(cfg->dev),
2552         .fc_ifindex = cfg->nh_ifindex,
2553         .fc_gateway = cfg->gw.ipv6,
2554         .fc_flags = cfg->nh_flags,
2555         .fc_nlinfo = cfg->nlinfo,
2556         .fc_encap = cfg->nh_encap,
2557         .fc_encap_type = cfg->nh_encap_type,
2558         .fc_is_fdb = cfg->nh_fdb,
2559     };
2560     int err;
2561
2562     if (!ipv6_addr_any(&cfg->gw.ipv6))
2563         fib6_cfg.fc_flags |= RTF_GATEWAY;
2564
2565     /* sets nh_dev if successful */
2566     err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL,
2567                       extack);
2568     if (err) {
2569         /* IPv6 is not enabled, don't call fib6_nh_release */
2570         if (err == -EAFNOSUPPORT)
2571             goto out;
2572         ipv6_stub->fib6_nh_release(fib6_nh);
2573     } else {
2574         nh->nh_flags = fib6_nh->fib_nh_flags;
2575     }
2576 out:
2577     return err;
2578 }
2579
2580 static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg,
2581                       struct netlink_ext_ack *extack)
2582 {
2583     struct nh_info *nhi;
2584     struct nexthop *nh;
2585     int err = 0;
2586
2587     nh = nexthop_alloc();
2588     if (!nh)
2589         return ERR_PTR(-ENOMEM);
2590
2591     nhi = kzalloc(sizeof(*nhi), GFP_KERNEL);
2592     if (!nhi) {
2593         kfree(nh);
2594         return ERR_PTR(-ENOMEM);
2595     }
2596
2597     nh->nh_flags = cfg->nh_flags;
2598     nh->net = net;
2599
2600     nhi->nh_parent = nh;
2601     nhi->family = cfg->nh_family;
2602     nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK;
2603
2604     if (cfg->nh_fdb)
2605         nhi->fdb_nh = 1;
2606
2607     if (cfg->nh_blackhole) {
2608         nhi->reject_nh = 1;
2609         cfg->nh_ifindex = net->loopback_dev->ifindex;
2610     }
2611
2612     switch (cfg->nh_family) {
2613     case AF_INET:
2614         err = nh_create_ipv4(net, nh, nhi, cfg, extack);
2615         break;
2616     case AF_INET6:
2617         err = nh_create_ipv6(net, nh, nhi, cfg, extack);
2618         break;
2619     }
2620
2621     if (err) {
2622         kfree(nhi);
2623         kfree(nh);
2624         return ERR_PTR(err);
2625     }
2626
2627     /* add the entry to the device based hash */
2628     if (!nhi->fdb_nh)
2629         nexthop_devhash_add(net, nhi);
2630
2631     rcu_assign_pointer(nh->nh_info, nhi);
2632
2633     return nh;
2634 }
2635
2636 /* called with rtnl lock held */
2637 static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
2638                    struct netlink_ext_ack *extack)
2639 {
2640     struct nexthop *nh;
2641     int err;
2642
2643     if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
2644         NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
2645         return ERR_PTR(-EINVAL);
2646     }
2647
2648     if (!cfg->nh_id) {
2649         cfg->nh_id = nh_find_unused_id(net);
2650         if (!cfg->nh_id) {
2651             NL_SET_ERR_MSG(extack, "No unused id");
2652             return ERR_PTR(-EINVAL);
2653         }
2654     }
2655
2656     if (cfg->nh_grp)
2657         nh = nexthop_create_group(net, cfg);
2658     else
2659         nh = nexthop_create(net, cfg, extack);
2660
2661     if (IS_ERR(nh))
2662         return nh;
2663
2664     refcount_set(&nh->refcnt, 1);
2665     nh->id = cfg->nh_id;
2666     nh->protocol = cfg->nh_protocol;
2667     nh->net = net;
2668
2669     err = insert_nexthop(net, nh, cfg, extack);
2670     if (err) {
2671         __remove_nexthop(net, nh, NULL);
2672         nexthop_put(nh);
2673         nh = ERR_PTR(err);
2674     }
2675
2676     return nh;
2677 }
2678
2679 static int rtm_nh_get_timer(struct nlattr *attr, unsigned long fallback,
2680                 unsigned long *timer_p, bool *has_p,
2681                 struct netlink_ext_ack *extack)
2682 {
2683     unsigned long timer;
2684     u32 value;
2685
2686     if (!attr) {
2687         *timer_p = fallback;
2688         *has_p = false;
2689         return 0;
2690     }
2691
2692     value = nla_get_u32(attr);
2693     timer = clock_t_to_jiffies(value);
2694     if (timer == ~0UL) {
2695         NL_SET_ERR_MSG(extack, "Timer value too large");
2696         return -EINVAL;
2697     }
2698
2699     *timer_p = timer;
2700     *has_p = true;
2701     return 0;
2702 }
2703
2704 static int rtm_to_nh_config_grp_res(struct nlattr *res, struct nh_config *cfg,
2705                     struct netlink_ext_ack *extack)
2706 {
2707     struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_policy_new)] = {};
2708     int err;
2709
2710     if (res) {
2711         err = nla_parse_nested(tb,
2712                        ARRAY_SIZE(rtm_nh_res_policy_new) - 1,
2713                        res, rtm_nh_res_policy_new, extack);
2714         if (err < 0)
2715             return err;
2716     }
2717
2718     if (tb[NHA_RES_GROUP_BUCKETS]) {
2719         cfg->nh_grp_res_num_buckets =
2720             nla_get_u16(tb[NHA_RES_GROUP_BUCKETS]);
2721         cfg->nh_grp_res_has_num_buckets = true;
2722         if (!cfg->nh_grp_res_num_buckets) {
2723             NL_SET_ERR_MSG(extack, "Number of buckets needs to be non-0");
2724             return -EINVAL;
2725         }
2726     }
2727
2728     err = rtm_nh_get_timer(tb[NHA_RES_GROUP_IDLE_TIMER],
2729                    NH_RES_DEFAULT_IDLE_TIMER,
2730                    &cfg->nh_grp_res_idle_timer,
2731                    &cfg->nh_grp_res_has_idle_timer,
2732                    extack);
2733     if (err)
2734         return err;
2735
2736     return rtm_nh_get_timer(tb[NHA_RES_GROUP_UNBALANCED_TIMER],
2737                 NH_RES_DEFAULT_UNBALANCED_TIMER,
2738                 &cfg->nh_grp_res_unbalanced_timer,
2739                 &cfg->nh_grp_res_has_unbalanced_timer,
2740                 extack);
2741 }
2742
2743 static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
2744                 struct nlmsghdr *nlh, struct nh_config *cfg,
2745                 struct netlink_ext_ack *extack)
2746 {
2747     struct nhmsg *nhm = nlmsg_data(nlh);
2748     struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_new)];
2749     int err;
2750
2751     err = nlmsg_parse(nlh, sizeof(*nhm), tb,
2752               ARRAY_SIZE(rtm_nh_policy_new) - 1,
2753               rtm_nh_policy_new, extack);
2754     if (err < 0)
2755         return err;
2756
2757     err = -EINVAL;
2758     if (nhm->resvd || nhm->nh_scope) {
2759         NL_SET_ERR_MSG(extack, "Invalid values in ancillary header");
2760         goto out;
2761     }
2762     if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
2763         NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
2764         goto out;
2765     }
2766
2767     switch (nhm->nh_family) {
2768     case AF_INET:
2769     case AF_INET6:
2770         break;
2771     case AF_UNSPEC:
2772         if (tb[NHA_GROUP])
2773             break;
2774         fallthrough;
2775     default:
2776         NL_SET_ERR_MSG(extack, "Invalid address family");
2777         goto out;
2778     }
2779
2780     memset(cfg, 0, sizeof(*cfg));
2781     cfg->nlflags = nlh->nlmsg_flags;
2782     cfg->nlinfo.portid = NETLINK_CB(skb).portid;
2783     cfg->nlinfo.nlh = nlh;
2784     cfg->nlinfo.nl_net = net;
2785
2786     cfg->nh_family = nhm->nh_family;
2787     cfg->nh_protocol = nhm->nh_protocol;
2788     cfg->nh_flags = nhm->nh_flags;
2789
2790     if (tb[NHA_ID])
2791         cfg->nh_id = nla_get_u32(tb[NHA_ID]);
2792
2793     if (tb[NHA_FDB]) {
2794         if (tb[NHA_OIF] || tb[NHA_BLACKHOLE] ||
2795             tb[NHA_ENCAP]   || tb[NHA_ENCAP_TYPE]) {
2796             NL_SET_ERR_MSG(extack, "Fdb attribute can not be used with encap, oif or blackhole");
2797             goto out;
2798         }
2799         if (nhm->nh_flags) {
2800             NL_SET_ERR_MSG(extack, "Unsupported nexthop flags in ancillary header");
2801             goto out;
2802         }
2803         cfg->nh_fdb = nla_get_flag(tb[NHA_FDB]);
2804     }
2805
2806     if (tb[NHA_GROUP]) {
2807         if (nhm->nh_family != AF_UNSPEC) {
2808             NL_SET_ERR_MSG(extack, "Invalid family for group");
2809             goto out;
2810         }
2811         cfg->nh_grp = tb[NHA_GROUP];
2812
2813         cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH;
2814         if (tb[NHA_GROUP_TYPE])
2815             cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]);
2816
2817         if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) {
2818             NL_SET_ERR_MSG(extack, "Invalid group type");
2819             goto out;
2820         }
2821         err = nh_check_attr_group(net, tb, ARRAY_SIZE(tb),
2822                       cfg->nh_grp_type, extack);
2823         if (err)
2824             goto out;
2825
2826         if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES)
2827             err = rtm_to_nh_config_grp_res(tb[NHA_RES_GROUP],
2828                                cfg, extack);
2829
2830         /* no other attributes should be set */
2831         goto out;
2832     }
2833
2834     if (tb[NHA_BLACKHOLE]) {
2835         if (tb[NHA_GATEWAY] || tb[NHA_OIF] ||
2836             tb[NHA_ENCAP]   || tb[NHA_ENCAP_TYPE] || tb[NHA_FDB]) {
2837             NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway, oif, encap or fdb");
2838             goto out;
2839         }
2840
2841         cfg->nh_blackhole = 1;
2842         err = 0;
2843         goto out;
2844     }
2845
2846     if (!cfg->nh_fdb && !tb[NHA_OIF]) {
2847         NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole and non-fdb nexthops");
2848         goto out;
2849     }
2850
2851     if (!cfg->nh_fdb && tb[NHA_OIF]) {
2852         cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]);
2853         if (cfg->nh_ifindex)
2854             cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex);
2855
2856         if (!cfg->dev) {
2857             NL_SET_ERR_MSG(extack, "Invalid device index");
2858             goto out;
2859         } else if (!(cfg->dev->flags & IFF_UP)) {
2860             NL_SET_ERR_MSG(extack, "Nexthop device is not up");
2861             err = -ENETDOWN;
2862             goto out;
2863         } else if (!netif_carrier_ok(cfg->dev)) {
2864             NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down");
2865             err = -ENETDOWN;
2866             goto out;
2867         }
2868     }
2869
2870     err = -EINVAL;
2871     if (tb[NHA_GATEWAY]) {
2872         struct nlattr *gwa = tb[NHA_GATEWAY];
2873
2874         switch (cfg->nh_family) {
2875         case AF_INET:
2876             if (nla_len(gwa) != sizeof(u32)) {
2877                 NL_SET_ERR_MSG(extack, "Invalid gateway");
2878                 goto out;
2879             }
2880             cfg->gw.ipv4 = nla_get_be32(gwa);
2881             break;
2882         case AF_INET6:
2883             if (nla_len(gwa) != sizeof(struct in6_addr)) {
2884                 NL_SET_ERR_MSG(extack, "Invalid gateway");
2885                 goto out;
2886             }
2887             cfg->gw.ipv6 = nla_get_in6_addr(gwa);
2888             break;
2889         default:
2890             NL_SET_ERR_MSG(extack,
2891                        "Unknown address family for gateway");
2892             goto out;
2893         }
2894     } else {
2895         /* device only nexthop (no gateway) */
2896         if (cfg->nh_flags & RTNH_F_ONLINK) {
2897             NL_SET_ERR_MSG(extack,
2898                        "ONLINK flag can not be set for nexthop without a gateway");
2899             goto out;
2900         }
2901     }
2902
2903     if (tb[NHA_ENCAP]) {
2904         cfg->nh_encap = tb[NHA_ENCAP];
2905
2906         if (!tb[NHA_ENCAP_TYPE]) {
2907             NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing");
2908             goto out;
2909         }
2910
2911         cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]);
2912         err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack);
2913         if (err < 0)
2914             goto out;
2915
2916     } else if (tb[NHA_ENCAP_TYPE]) {
2917         NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing");
2918         goto out;
2919     }
2920
2921
2922     err = 0;
2923 out:
2924     return err;
2925 }
2926
2927 /* rtnl */
2928 static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
2929                struct netlink_ext_ack *extack)
2930 {
2931     struct net *net = sock_net(skb->sk);
2932     struct nh_config cfg;
2933     struct nexthop *nh;
2934     int err;
2935
2936     err = rtm_to_nh_config(net, skb, nlh, &cfg, extack);
2937     if (!err) {
2938         nh = nexthop_add(net, &cfg, extack);
2939         if (IS_ERR(nh))
2940             err = PTR_ERR(nh);
2941     }
2942
2943     return err;
2944 }
2945
2946 static int __nh_valid_get_del_req(const struct nlmsghdr *nlh,
2947                   struct nlattr **tb, u32 *id,
2948                   struct netlink_ext_ack *extack)
2949 {
2950     struct nhmsg *nhm = nlmsg_data(nlh);
2951
2952     if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
2953         NL_SET_ERR_MSG(extack, "Invalid values in header");
2954         return -EINVAL;
2955     }
2956
2957     if (!tb[NHA_ID]) {
2958         NL_SET_ERR_MSG(extack, "Nexthop id is missing");
2959         return -EINVAL;
2960     }
2961
2962     *id = nla_get_u32(tb[NHA_ID]);
2963     if (!(*id)) {
2964         NL_SET_ERR_MSG(extack, "Invalid nexthop id");
2965         return -EINVAL;
2966     }
2967
2968     return 0;
2969 }
2970
2971 static int nh_valid_get_del_req(const struct nlmsghdr *nlh, u32 *id,
2972                 struct netlink_ext_ack *extack)
2973 {
2974     struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get)];
2975     int err;
2976
2977     err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
2978               ARRAY_SIZE(rtm_nh_policy_get) - 1,
2979               rtm_nh_policy_get, extack);
2980     if (err < 0)
2981         return err;
2982
2983     return __nh_valid_get_del_req(nlh, tb, id, extack);
2984 }
2985
2986 /* rtnl */
2987 static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
2988                struct netlink_ext_ack *extack)
2989 {
2990     struct net *net = sock_net(skb->sk);
2991     struct nl_info nlinfo = {
2992         .nlh = nlh,
2993         .nl_net = net,
2994         .portid = NETLINK_CB(skb).portid,
2995     };
2996     struct nexthop *nh;
2997     int err;
2998     u32 id;
2999
3000     err = nh_valid_get_del_req(nlh, &id, extack);
3001     if (err)
3002         return err;
3003
3004     nh = nexthop_find_by_id(net, id);
3005     if (!nh)
3006         return -ENOENT;
3007
3008     remove_nexthop(net, nh, &nlinfo);
3009
3010     return 0;
3011 }
3012
3013 /* rtnl */
3014 static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3015                struct netlink_ext_ack *extack)
3016 {
3017     struct net *net = sock_net(in_skb->sk);
3018     struct sk_buff *skb = NULL;
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     err = -ENOBUFS;
3028     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3029     if (!skb)
3030         goto out;
3031
3032     err = -ENOENT;
3033     nh = nexthop_find_by_id(net, id);
3034     if (!nh)
3035         goto errout_free;
3036
3037     err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid,
3038                nlh->nlmsg_seq, 0);
3039     if (err < 0) {
3040         WARN_ON(err == -EMSGSIZE);
3041         goto errout_free;
3042     }
3043
3044     err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3045 out:
3046     return err;
3047 errout_free:
3048     kfree_skb(skb);
3049     goto out;
3050 }
3051
3052 struct nh_dump_filter {
3053     u32 nh_id;
3054     int dev_idx;
3055     int master_idx;
3056     bool group_filter;
3057     bool fdb_filter;
3058     u32 res_bucket_nh_id;
3059 };
3060
3061 static bool nh_dump_filtered(struct nexthop *nh,
3062                  struct nh_dump_filter *filter, u8 family)
3063 {
3064     const struct net_device *dev;
3065     const struct nh_info *nhi;
3066
3067     if (filter->group_filter && !nh->is_group)
3068         return true;
3069
3070     if (!filter->dev_idx && !filter->master_idx && !family)
3071         return false;
3072
3073     if (nh->is_group)
3074         return true;
3075
3076     nhi = rtnl_dereference(nh->nh_info);
3077     if (family && nhi->family != family)
3078         return true;
3079
3080     dev = nhi->fib_nhc.nhc_dev;
3081     if (filter->dev_idx && (!dev || dev->ifindex != filter->dev_idx))
3082         return true;
3083
3084     if (filter->master_idx) {
3085         struct net_device *master;
3086
3087         if (!dev)
3088             return true;
3089
3090         master = netdev_master_upper_dev_get((struct net_device *)dev);
3091         if (!master || master->ifindex != filter->master_idx)
3092             return true;
3093     }
3094
3095     return false;
3096 }
3097
3098 static int __nh_valid_dump_req(const struct nlmsghdr *nlh, struct nlattr **tb,
3099                    struct nh_dump_filter *filter,
3100                    struct netlink_ext_ack *extack)
3101 {
3102     struct nhmsg *nhm;
3103     u32 idx;
3104
3105     if (tb[NHA_OIF]) {
3106         idx = nla_get_u32(tb[NHA_OIF]);
3107         if (idx > INT_MAX) {
3108             NL_SET_ERR_MSG(extack, "Invalid device index");
3109             return -EINVAL;
3110         }
3111         filter->dev_idx = idx;
3112     }
3113     if (tb[NHA_MASTER]) {
3114         idx = nla_get_u32(tb[NHA_MASTER]);
3115         if (idx > INT_MAX) {
3116             NL_SET_ERR_MSG(extack, "Invalid master device index");
3117             return -EINVAL;
3118         }
3119         filter->master_idx = idx;
3120     }
3121     filter->group_filter = nla_get_flag(tb[NHA_GROUPS]);
3122     filter->fdb_filter = nla_get_flag(tb[NHA_FDB]);
3123
3124     nhm = nlmsg_data(nlh);
3125     if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
3126         NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request");
3127         return -EINVAL;
3128     }
3129
3130     return 0;
3131 }
3132
3133 static int nh_valid_dump_req(const struct nlmsghdr *nlh,
3134                  struct nh_dump_filter *filter,
3135                  struct netlink_callback *cb)
3136 {
3137     struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump)];
3138     int err;
3139
3140     err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3141               ARRAY_SIZE(rtm_nh_policy_dump) - 1,
3142               rtm_nh_policy_dump, cb->extack);
3143     if (err < 0)
3144         return err;
3145
3146     return __nh_valid_dump_req(nlh, tb, filter, cb->extack);
3147 }
3148
3149 struct rtm_dump_nh_ctx {
3150     u32 idx;
3151 };
3152
3153 static struct rtm_dump_nh_ctx *
3154 rtm_dump_nh_ctx(struct netlink_callback *cb)
3155 {
3156     struct rtm_dump_nh_ctx *ctx = (void *)cb->ctx;
3157
3158     BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
3159     return ctx;
3160 }
3161
3162 static int rtm_dump_walk_nexthops(struct sk_buff *skb,
3163                   struct netlink_callback *cb,
3164                   struct rb_root *root,
3165                   struct rtm_dump_nh_ctx *ctx,
3166                   int (*nh_cb)(struct sk_buff *skb,
3167                            struct netlink_callback *cb,
3168                            struct nexthop *nh, void *data),
3169                   void *data)
3170 {
3171     struct rb_node *node;
3172     int s_idx;
3173     int err;
3174
3175     s_idx = ctx->idx;
3176     for (node = rb_first(root); node; node = rb_next(node)) {
3177         struct nexthop *nh;
3178
3179         nh = rb_entry(node, struct nexthop, rb_node);
3180         if (nh->id < s_idx)
3181             continue;
3182
3183         ctx->idx = nh->id;
3184         err = nh_cb(skb, cb, nh, data);
3185         if (err)
3186             return err;
3187     }
3188
3189     ctx->idx++;
3190     return 0;
3191 }
3192
3193 static int rtm_dump_nexthop_cb(struct sk_buff *skb, struct netlink_callback *cb,
3194                    struct nexthop *nh, void *data)
3195 {
3196     struct nhmsg *nhm = nlmsg_data(cb->nlh);
3197     struct nh_dump_filter *filter = data;
3198
3199     if (nh_dump_filtered(nh, filter, nhm->nh_family))
3200         return 0;
3201
3202     return nh_fill_node(skb, nh, RTM_NEWNEXTHOP,
3203                 NETLINK_CB(cb->skb).portid,
3204                 cb->nlh->nlmsg_seq, NLM_F_MULTI);
3205 }
3206
3207 /* rtnl */
3208 static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
3209 {
3210     struct rtm_dump_nh_ctx *ctx = rtm_dump_nh_ctx(cb);
3211     struct net *net = sock_net(skb->sk);
3212     struct rb_root *root = &net->nexthop.rb_root;
3213     struct nh_dump_filter filter = {};
3214     int err;
3215
3216     err = nh_valid_dump_req(cb->nlh, &filter, cb);
3217     if (err < 0)
3218         return err;
3219
3220     err = rtm_dump_walk_nexthops(skb, cb, root, ctx,
3221                      &rtm_dump_nexthop_cb, &filter);
3222     if (err < 0) {
3223         if (likely(skb->len))
3224             goto out;
3225         goto out_err;
3226     }
3227
3228 out:
3229     err = skb->len;
3230 out_err:
3231     cb->seq = net->nexthop.seq;
3232     nl_dump_check_consistent(cb, nlmsg_hdr(skb));
3233     return err;
3234 }
3235
3236 static struct nexthop *
3237 nexthop_find_group_resilient(struct net *net, u32 id,
3238                  struct netlink_ext_ack *extack)
3239 {
3240     struct nh_group *nhg;
3241     struct nexthop *nh;
3242
3243     nh = nexthop_find_by_id(net, id);
3244     if (!nh)
3245         return ERR_PTR(-ENOENT);
3246
3247     if (!nh->is_group) {
3248         NL_SET_ERR_MSG(extack, "Not a nexthop group");
3249         return ERR_PTR(-EINVAL);
3250     }
3251
3252     nhg = rtnl_dereference(nh->nh_grp);
3253     if (!nhg->resilient) {
3254         NL_SET_ERR_MSG(extack, "Nexthop group not of type resilient");
3255         return ERR_PTR(-EINVAL);
3256     }
3257
3258     return nh;
3259 }
3260
3261 static int nh_valid_dump_nhid(struct nlattr *attr, u32 *nh_id_p,
3262                   struct netlink_ext_ack *extack)
3263 {
3264     u32 idx;
3265
3266     if (attr) {
3267         idx = nla_get_u32(attr);
3268         if (!idx) {
3269             NL_SET_ERR_MSG(extack, "Invalid nexthop id");
3270             return -EINVAL;
3271         }
3272         *nh_id_p = idx;
3273     } else {
3274         *nh_id_p = 0;
3275     }
3276
3277     return 0;
3278 }
3279
3280 static int nh_valid_dump_bucket_req(const struct nlmsghdr *nlh,
3281                     struct nh_dump_filter *filter,
3282                     struct netlink_callback *cb)
3283 {
3284     struct nlattr *res_tb[ARRAY_SIZE(rtm_nh_res_bucket_policy_dump)];
3285     struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump_bucket)];
3286     int err;
3287
3288     err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3289               ARRAY_SIZE(rtm_nh_policy_dump_bucket) - 1,
3290               rtm_nh_policy_dump_bucket, NULL);
3291     if (err < 0)
3292         return err;
3293
3294     err = nh_valid_dump_nhid(tb[NHA_ID], &filter->nh_id, cb->extack);
3295     if (err)
3296         return err;
3297
3298     if (tb[NHA_RES_BUCKET]) {
3299         size_t max = ARRAY_SIZE(rtm_nh_res_bucket_policy_dump) - 1;
3300
3301         err = nla_parse_nested(res_tb, max,
3302                        tb[NHA_RES_BUCKET],
3303                        rtm_nh_res_bucket_policy_dump,
3304                        cb->extack);
3305         if (err < 0)
3306             return err;
3307
3308         err = nh_valid_dump_nhid(res_tb[NHA_RES_BUCKET_NH_ID],
3309                      &filter->res_bucket_nh_id,
3310                      cb->extack);
3311         if (err)
3312             return err;
3313     }
3314
3315     return __nh_valid_dump_req(nlh, tb, filter, cb->extack);
3316 }
3317
3318 struct rtm_dump_res_bucket_ctx {
3319     struct rtm_dump_nh_ctx nh;
3320     u16 bucket_index;
3321     u32 done_nh_idx; /* 1 + the index of the last fully processed NH. */
3322 };
3323
3324 static struct rtm_dump_res_bucket_ctx *
3325 rtm_dump_res_bucket_ctx(struct netlink_callback *cb)
3326 {
3327     struct rtm_dump_res_bucket_ctx *ctx = (void *)cb->ctx;
3328
3329     BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
3330     return ctx;
3331 }
3332
3333 struct rtm_dump_nexthop_bucket_data {
3334     struct rtm_dump_res_bucket_ctx *ctx;
3335     struct nh_dump_filter filter;
3336 };
3337
3338 static int rtm_dump_nexthop_bucket_nh(struct sk_buff *skb,
3339                       struct netlink_callback *cb,
3340                       struct nexthop *nh,
3341                       struct rtm_dump_nexthop_bucket_data *dd)
3342 {
3343     u32 portid = NETLINK_CB(cb->skb).portid;
3344     struct nhmsg *nhm = nlmsg_data(cb->nlh);
3345     struct nh_res_table *res_table;
3346     struct nh_group *nhg;
3347     u16 bucket_index;
3348     int err;
3349
3350     if (dd->ctx->nh.idx < dd->ctx->done_nh_idx)
3351         return 0;
3352
3353     nhg = rtnl_dereference(nh->nh_grp);
3354     res_table = rtnl_dereference(nhg->res_table);
3355     for (bucket_index = dd->ctx->bucket_index;
3356          bucket_index < res_table->num_nh_buckets;
3357          bucket_index++) {
3358         struct nh_res_bucket *bucket;
3359         struct nh_grp_entry *nhge;
3360
3361         bucket = &res_table->nh_buckets[bucket_index];
3362         nhge = rtnl_dereference(bucket->nh_entry);
3363         if (nh_dump_filtered(nhge->nh, &dd->filter, nhm->nh_family))
3364             continue;
3365
3366         if (dd->filter.res_bucket_nh_id &&
3367             dd->filter.res_bucket_nh_id != nhge->nh->id)
3368             continue;
3369
3370         err = nh_fill_res_bucket(skb, nh, bucket, bucket_index,
3371                      RTM_NEWNEXTHOPBUCKET, portid,
3372                      cb->nlh->nlmsg_seq, NLM_F_MULTI,
3373                      cb->extack);
3374         if (err < 0) {
3375             if (likely(skb->len))
3376                 goto out;
3377             goto out_err;
3378         }
3379     }
3380
3381     dd->ctx->done_nh_idx = dd->ctx->nh.idx + 1;
3382     bucket_index = 0;
3383
3384 out:
3385     err = skb->len;
3386 out_err:
3387     dd->ctx->bucket_index = bucket_index;
3388     return err;
3389 }
3390
3391 static int rtm_dump_nexthop_bucket_cb(struct sk_buff *skb,
3392                       struct netlink_callback *cb,
3393                       struct nexthop *nh, void *data)
3394 {
3395     struct rtm_dump_nexthop_bucket_data *dd = data;
3396     struct nh_group *nhg;
3397
3398     if (!nh->is_group)
3399         return 0;
3400
3401     nhg = rtnl_dereference(nh->nh_grp);
3402     if (!nhg->resilient)
3403         return 0;
3404
3405     return rtm_dump_nexthop_bucket_nh(skb, cb, nh, dd);
3406 }
3407
3408 /* rtnl */
3409 static int rtm_dump_nexthop_bucket(struct sk_buff *skb,
3410                    struct netlink_callback *cb)
3411 {
3412     struct rtm_dump_res_bucket_ctx *ctx = rtm_dump_res_bucket_ctx(cb);
3413     struct rtm_dump_nexthop_bucket_data dd = { .ctx = ctx };
3414     struct net *net = sock_net(skb->sk);
3415     struct nexthop *nh;
3416     int err;
3417
3418     err = nh_valid_dump_bucket_req(cb->nlh, &dd.filter, cb);
3419     if (err)
3420         return err;
3421
3422     if (dd.filter.nh_id) {
3423         nh = nexthop_find_group_resilient(net, dd.filter.nh_id,
3424                           cb->extack);
3425         if (IS_ERR(nh))
3426             return PTR_ERR(nh);
3427         err = rtm_dump_nexthop_bucket_nh(skb, cb, nh, &dd);
3428     } else {
3429         struct rb_root *root = &net->nexthop.rb_root;
3430
3431         err = rtm_dump_walk_nexthops(skb, cb, root, &ctx->nh,
3432                          &rtm_dump_nexthop_bucket_cb, &dd);
3433     }
3434
3435     if (err < 0) {
3436         if (likely(skb->len))
3437             goto out;
3438         goto out_err;
3439     }
3440
3441 out:
3442     err = skb->len;
3443 out_err:
3444     cb->seq = net->nexthop.seq;
3445     nl_dump_check_consistent(cb, nlmsg_hdr(skb));
3446     return err;
3447 }
3448
3449 static int nh_valid_get_bucket_req_res_bucket(struct nlattr *res,
3450                           u16 *bucket_index,
3451                           struct netlink_ext_ack *extack)
3452 {
3453     struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_bucket_policy_get)];
3454     int err;
3455
3456     err = nla_parse_nested(tb, ARRAY_SIZE(rtm_nh_res_bucket_policy_get) - 1,
3457                    res, rtm_nh_res_bucket_policy_get, extack);
3458     if (err < 0)
3459         return err;
3460
3461     if (!tb[NHA_RES_BUCKET_INDEX]) {
3462         NL_SET_ERR_MSG(extack, "Bucket index is missing");
3463         return -EINVAL;
3464     }
3465
3466     *bucket_index = nla_get_u16(tb[NHA_RES_BUCKET_INDEX]);
3467     return 0;
3468 }
3469
3470 static int nh_valid_get_bucket_req(const struct nlmsghdr *nlh,
3471                    u32 *id, u16 *bucket_index,
3472                    struct netlink_ext_ack *extack)
3473 {
3474     struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get_bucket)];
3475     int err;
3476
3477     err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
3478               ARRAY_SIZE(rtm_nh_policy_get_bucket) - 1,
3479               rtm_nh_policy_get_bucket, extack);
3480     if (err < 0)
3481         return err;
3482
3483     err = __nh_valid_get_del_req(nlh, tb, id, extack);
3484     if (err)
3485         return err;
3486
3487     if (!tb[NHA_RES_BUCKET]) {
3488         NL_SET_ERR_MSG(extack, "Bucket information is missing");
3489         return -EINVAL;
3490     }
3491
3492     err = nh_valid_get_bucket_req_res_bucket(tb[NHA_RES_BUCKET],
3493                          bucket_index, extack);
3494     if (err)
3495         return err;
3496
3497     return 0;
3498 }
3499
3500 /* rtnl */
3501 static int rtm_get_nexthop_bucket(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3502                   struct netlink_ext_ack *extack)
3503 {
3504     struct net *net = sock_net(in_skb->sk);
3505     struct nh_res_table *res_table;
3506     struct sk_buff *skb = NULL;
3507     struct nh_group *nhg;
3508     struct nexthop *nh;
3509     u16 bucket_index;
3510     int err;
3511     u32 id;
3512
3513     err = nh_valid_get_bucket_req(nlh, &id, &bucket_index, extack);
3514     if (err)
3515         return err;
3516
3517     nh = nexthop_find_group_resilient(net, id, extack);
3518     if (IS_ERR(nh))
3519         return PTR_ERR(nh);
3520
3521     nhg = rtnl_dereference(nh->nh_grp);
3522     res_table = rtnl_dereference(nhg->res_table);
3523     if (bucket_index >= res_table->num_nh_buckets) {
3524         NL_SET_ERR_MSG(extack, "Bucket index out of bounds");
3525         return -ENOENT;
3526     }
3527
3528     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3529     if (!skb)
3530         return -ENOBUFS;
3531
3532     err = nh_fill_res_bucket(skb, nh, &res_table->nh_buckets[bucket_index],
3533                  bucket_index, RTM_NEWNEXTHOPBUCKET,
3534                  NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
3535                  0, extack);
3536     if (err < 0) {
3537         WARN_ON(err == -EMSGSIZE);
3538         goto errout_free;
3539     }
3540
3541     return rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3542
3543 errout_free:
3544     kfree_skb(skb);
3545     return err;
3546 }
3547
3548 static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu)
3549 {
3550     unsigned int hash = nh_dev_hashfn(dev->ifindex);
3551     struct net *net = dev_net(dev);
3552     struct hlist_head *head = &net->nexthop.devhash[hash];
3553     struct hlist_node *n;
3554     struct nh_info *nhi;
3555
3556     hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
3557         if (nhi->fib_nhc.nhc_dev == dev) {
3558             if (nhi->family == AF_INET)
3559                 fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu,
3560                            orig_mtu);
3561         }
3562     }
3563 }
3564
3565 /* rtnl */
3566 static int nh_netdev_event(struct notifier_block *this,
3567                unsigned long event, void *ptr)
3568 {
3569     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3570     struct netdev_notifier_info_ext *info_ext;
3571
3572     switch (event) {
3573     case NETDEV_DOWN:
3574     case NETDEV_UNREGISTER:
3575         nexthop_flush_dev(dev, event);
3576         break;
3577     case NETDEV_CHANGE:
3578         if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP)))
3579             nexthop_flush_dev(dev, event);
3580         break;
3581     case NETDEV_CHANGEMTU:
3582         info_ext = ptr;
3583         nexthop_sync_mtu(dev, info_ext->ext.mtu);
3584         rt_cache_flush(dev_net(dev));
3585         break;
3586     }
3587     return NOTIFY_DONE;
3588 }
3589
3590 static struct notifier_block nh_netdev_notifier = {
3591     .notifier_call = nh_netdev_event,
3592 };
3593
3594 static int nexthops_dump(struct net *net, struct notifier_block *nb,
3595              enum nexthop_event_type event_type,
3596              struct netlink_ext_ack *extack)
3597 {
3598     struct rb_root *root = &net->nexthop.rb_root;
3599     struct rb_node *node;
3600     int err = 0;
3601
3602     for (node = rb_first(root); node; node = rb_next(node)) {
3603         struct nexthop *nh;
3604
3605         nh = rb_entry(node, struct nexthop, rb_node);
3606         err = call_nexthop_notifier(nb, net, event_type, nh, extack);
3607         if (err)
3608             break;
3609     }
3610
3611     return err;
3612 }
3613
3614 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
3615                   struct netlink_ext_ack *extack)
3616 {
3617     int err;
3618
3619     rtnl_lock();
3620     err = nexthops_dump(net, nb, NEXTHOP_EVENT_REPLACE, extack);
3621     if (err)
3622         goto unlock;
3623     err = blocking_notifier_chain_register(&net->nexthop.notifier_chain,
3624                            nb);
3625 unlock:
3626     rtnl_unlock();
3627     return err;
3628 }
3629 EXPORT_SYMBOL(register_nexthop_notifier);
3630
3631 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
3632 {
3633     int err;
3634
3635     rtnl_lock();
3636     err = blocking_notifier_chain_unregister(&net->nexthop.notifier_chain,
3637                          nb);
3638     if (err)
3639         goto unlock;
3640     nexthops_dump(net, nb, NEXTHOP_EVENT_DEL, NULL);
3641 unlock:
3642     rtnl_unlock();
3643     return err;
3644 }
3645 EXPORT_SYMBOL(unregister_nexthop_notifier);
3646
3647 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap)
3648 {
3649     struct nexthop *nexthop;
3650
3651     rcu_read_lock();
3652
3653     nexthop = nexthop_find_by_id(net, id);
3654     if (!nexthop)
3655         goto out;
3656
3657     nexthop->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
3658     if (offload)
3659         nexthop->nh_flags |= RTNH_F_OFFLOAD;
3660     if (trap)
3661         nexthop->nh_flags |= RTNH_F_TRAP;
3662
3663 out:
3664     rcu_read_unlock();
3665 }
3666 EXPORT_SYMBOL(nexthop_set_hw_flags);
3667
3668 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
3669                  bool offload, bool trap)
3670 {
3671     struct nh_res_table *res_table;
3672     struct nh_res_bucket *bucket;
3673     struct nexthop *nexthop;
3674     struct nh_group *nhg;
3675
3676     rcu_read_lock();
3677
3678     nexthop = nexthop_find_by_id(net, id);
3679     if (!nexthop || !nexthop->is_group)
3680         goto out;
3681
3682     nhg = rcu_dereference(nexthop->nh_grp);
3683     if (!nhg->resilient)
3684         goto out;
3685
3686     if (bucket_index >= nhg->res_table->num_nh_buckets)
3687         goto out;
3688
3689     res_table = rcu_dereference(nhg->res_table);
3690     bucket = &res_table->nh_buckets[bucket_index];
3691     bucket->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
3692     if (offload)
3693         bucket->nh_flags |= RTNH_F_OFFLOAD;
3694     if (trap)
3695         bucket->nh_flags |= RTNH_F_TRAP;
3696
3697 out:
3698     rcu_read_unlock();
3699 }
3700 EXPORT_SYMBOL(nexthop_bucket_set_hw_flags);
3701
3702 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
3703                      unsigned long *activity)
3704 {
3705     struct nh_res_table *res_table;
3706     struct nexthop *nexthop;
3707     struct nh_group *nhg;
3708     u16 i;
3709
3710     rcu_read_lock();
3711
3712     nexthop = nexthop_find_by_id(net, id);
3713     if (!nexthop || !nexthop->is_group)
3714         goto out;
3715
3716     nhg = rcu_dereference(nexthop->nh_grp);
3717     if (!nhg->resilient)
3718         goto out;
3719
3720     /* Instead of silently ignoring some buckets, demand that the sizes
3721      * be the same.
3722      */
3723     res_table = rcu_dereference(nhg->res_table);
3724     if (num_buckets != res_table->num_nh_buckets)
3725         goto out;
3726
3727     for (i = 0; i < num_buckets; i++) {
3728         if (test_bit(i, activity))
3729             nh_res_bucket_set_busy(&res_table->nh_buckets[i]);
3730     }
3731
3732 out:
3733     rcu_read_unlock();
3734 }
3735 EXPORT_SYMBOL(nexthop_res_grp_activity_update);
3736
3737 static void __net_exit nexthop_net_exit_batch(struct list_head *net_list)
3738 {
3739     struct net *net;
3740
3741     rtnl_lock();
3742     list_for_each_entry(net, net_list, exit_list) {
3743         flush_all_nexthops(net);
3744         kfree(net->nexthop.devhash);
3745     }
3746     rtnl_unlock();
3747 }
3748
3749 static int __net_init nexthop_net_init(struct net *net)
3750 {
3751     size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE;
3752
3753     net->nexthop.rb_root = RB_ROOT;
3754     net->nexthop.devhash = kzalloc(sz, GFP_KERNEL);
3755     if (!net->nexthop.devhash)
3756         return -ENOMEM;
3757     BLOCKING_INIT_NOTIFIER_HEAD(&net->nexthop.notifier_chain);
3758
3759     return 0;
3760 }
3761
3762 static struct pernet_operations nexthop_net_ops = {
3763     .init = nexthop_net_init,
3764     .exit_batch = nexthop_net_exit_batch,
3765 };
3766
3767 static int __init nexthop_init(void)
3768 {
3769     register_pernet_subsys(&nexthop_net_ops);
3770
3771     register_netdevice_notifier(&nh_netdev_notifier);
3772
3773     rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3774     rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0);
3775     rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop,
3776               rtm_dump_nexthop, 0);
3777
3778     rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3779     rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
3780
3781     rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
3782     rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
3783
3784     rtnl_register(PF_UNSPEC, RTM_GETNEXTHOPBUCKET, rtm_get_nexthop_bucket,
3785               rtm_dump_nexthop_bucket, 0);
3786
3787     return 0;
3788 }
3789 subsys_initcall(nexthop_init);