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linux-stable/net/ipv4/nexthop.c
Petr Machata 283a72a559 nexthop: Add implementation of resilient next-hop groups 
At this moment, there is only one type of next-hop group: an mpath group,
which implements the hash-threshold algorithm.

To select a next hop, hash-threshold algorithm first assigns a range of
hashes to each next hop in the group, and then selects the next hop by
comparing the SKB hash with the individual ranges. When a next hop is
removed from the group, the ranges are recomputed, which leads to
reassignment of parts of hash space from one next hop to another. While
there will usually be some overlap between the previous and the new
distribution, some traffic flows change the next hop that they resolve to.
That causes problems e.g. as established TCP connections are reset, because
the traffic is forwarded to a server that is not familiar with the
connection.

Resilient hashing is a technique to address the above problem. Resilient
next-hop group has another layer of indirection between the group itself
and its constituent next hops: a hash table. The selection algorithm uses a
straightforward modulo operation to choose a hash bucket, and then reads
the next hop that this bucket contains, and forwards traffic there.

This indirection brings an important feature. In the hash-threshold
algorithm, the range of hashes associated with a next hop must be
continuous. With a hash table, mapping between the hash table buckets and
the individual next hops is arbitrary. Therefore when a next hop is deleted
the buckets that held it are simply reassigned to other next hops. When
weights of next hops in a group are altered, it may be possible to choose a
subset of buckets that are currently not used for forwarding traffic, and
use those to satisfy the new next-hop distribution demands, keeping the
"busy" buckets intact. This way, established flows are ideally kept being
forwarded to the same endpoints through the same paths as before the
next-hop group change.

In a nutshell, the algorithm works as follows. Each next hop has a number
of buckets that it wants to have, according to its weight and the number of
buckets in the hash table. In case of an event that might cause bucket
allocation change, the numbers for individual next hops are updated,
similarly to how ranges are updated for mpath group next hops. Following
that, a new "upkeep" algorithm runs, and for idle buckets that belong to a
next hop that is currently occupying more buckets than it wants (it is
"overweight"), it migrates the buckets to one of the next hops that has
fewer buckets than it wants (it is "underweight"). If, after this, there
are still underweight next hops, another upkeep run is scheduled to a
future time.

Chances are there are not enough "idle" buckets to satisfy the new demands.
The algorithm has knobs to select both what it means for a bucket to be
idle, and for whether and when to forcefully migrate buckets if there keeps
being an insufficient number of idle buckets.

There are three users of the resilient data structures.

- The forwarding code accesses them under RCU, and does not modify them
  except for updating the time a selected bucket was last used.

- Netlink code, running under RTNL, which may modify the data.

- The delayed upkeep code, which may modify the data. This runs unlocked,
  and mutual exclusion between the RTNL code and the delayed upkeep is
  maintained by canceling the delayed work synchronously before the RTNL
  code touches anything. Later it restarts the delayed work if necessary.

The RTNL code has to implement next-hop group replacement, next hop
removal, etc. For removal, the mpath code uses a neat trick of having a
backup next hop group structure, doing the necessary changes offline, and
then RCU-swapping them in. However, the hash tables for resilient hashing
are about an order of magnitude larger than the groups themselves (the size
might be e.g. 4K entries), and it was felt that keeping two of them is an
overkill. Both the primary next-hop group and the spare therefore use the
same resilient table, and writers are careful to keep all references valid
for the forwarding code. The hash table references next-hop group entries
from the next-hop group that is currently in the primary role (i.e. not
spare). During the transition from primary to spare, the table references a
mix of both the primary group and the spare. When a next hop is deleted,
the corresponding buckets are not set to NULL, but instead marked as empty,
so that the pointer is valid and can be used by the forwarding code. The
buckets are then migrated to a new next-hop group entry during upkeep. The
only times that the hash table is invalid is the very beginning and very
end of its lifetime. Between those points, it is always kept valid.

This patch introduces the core support code itself. It does not handle
notifications towards drivers, which are kept as if the group were an mpath
one. It does not handle netlink either. The only bit currently exposed to
user space is the new next-hop group type, and that is currently bounced.
There is therefore no way to actually access this code.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-11 16:12:59 -08:00

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// SPDX-License-Identifier: GPL-2.0
/* Generic nexthop implementation
*
* Copyright (c) 2017-19 Cumulus Networks
* Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
*/
#include <linux/nexthop.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <net/arp.h>
#include <net/ipv6_stubs.h>
#include <net/lwtunnel.h>
#include <net/ndisc.h>
#include <net/nexthop.h>
#include <net/route.h>
#include <net/sock.h>
static void remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo);
#define NH_DEV_HASHBITS 8
#define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS)
static const struct nla_policy rtm_nh_policy_new[] = {
[NHA_ID] = { .type = NLA_U32 },
[NHA_GROUP] = { .type = NLA_BINARY },
[NHA_GROUP_TYPE] = { .type = NLA_U16 },
[NHA_BLACKHOLE] = { .type = NLA_FLAG },
[NHA_OIF] = { .type = NLA_U32 },
[NHA_GATEWAY] = { .type = NLA_BINARY },
[NHA_ENCAP_TYPE] = { .type = NLA_U16 },
[NHA_ENCAP] = { .type = NLA_NESTED },
[NHA_FDB] = { .type = NLA_FLAG },
};
static const struct nla_policy rtm_nh_policy_get[] = {
[NHA_ID] = { .type = NLA_U32 },
};
static const struct nla_policy rtm_nh_policy_dump[] = {
[NHA_OIF] = { .type = NLA_U32 },
[NHA_GROUPS] = { .type = NLA_FLAG },
[NHA_MASTER] = { .type = NLA_U32 },
[NHA_FDB] = { .type = NLA_FLAG },
};
static bool nexthop_notifiers_is_empty(struct net *net)
{
return !net->nexthop.notifier_chain.head;
}
static void
__nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
const struct nh_info *nhi)
{
nh_info->dev = nhi->fib_nhc.nhc_dev;
nh_info->gw_family = nhi->fib_nhc.nhc_gw_family;
if (nh_info->gw_family == AF_INET)
nh_info->ipv4 = nhi->fib_nhc.nhc_gw.ipv4;
else if (nh_info->gw_family == AF_INET6)
nh_info->ipv6 = nhi->fib_nhc.nhc_gw.ipv6;
nh_info->is_reject = nhi->reject_nh;
nh_info->is_fdb = nhi->fdb_nh;
nh_info->has_encap = !!nhi->fib_nhc.nhc_lwtstate;
}
static int nh_notifier_single_info_init(struct nh_notifier_info *info,
const struct nexthop *nh)
{
struct nh_info *nhi = rtnl_dereference(nh->nh_info);
info->type = NH_NOTIFIER_INFO_TYPE_SINGLE;
info->nh = kzalloc(sizeof(*info->nh), GFP_KERNEL);
if (!info->nh)
return -ENOMEM;
__nh_notifier_single_info_init(info->nh, nhi);
return 0;
}
static void nh_notifier_single_info_fini(struct nh_notifier_info *info)
{
kfree(info->nh);
}
static int nh_notifier_mp_info_init(struct nh_notifier_info *info,
struct nh_group *nhg)
{
u16 num_nh = nhg->num_nh;
int i;
info->type = NH_NOTIFIER_INFO_TYPE_GRP;
info->nh_grp = kzalloc(struct_size(info->nh_grp, nh_entries, num_nh),
GFP_KERNEL);
if (!info->nh_grp)
return -ENOMEM;
info->nh_grp->num_nh = num_nh;
info->nh_grp->is_fdb = nhg->fdb_nh;
for (i = 0; i < num_nh; i++) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
struct nh_info *nhi;
nhi = rtnl_dereference(nhge->nh->nh_info);
info->nh_grp->nh_entries[i].id = nhge->nh->id;
info->nh_grp->nh_entries[i].weight = nhge->weight;
__nh_notifier_single_info_init(&info->nh_grp->nh_entries[i].nh,
nhi);
}
return 0;
}
static int nh_notifier_grp_info_init(struct nh_notifier_info *info,
const struct nexthop *nh)
{
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
if (nhg->mpath)
return nh_notifier_mp_info_init(info, nhg);
return -EINVAL;
}
static void nh_notifier_grp_info_fini(struct nh_notifier_info *info,
const struct nexthop *nh)
{
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
if (nhg->mpath)
kfree(info->nh_grp);
}
static int nh_notifier_info_init(struct nh_notifier_info *info,
const struct nexthop *nh)
{
info->id = nh->id;
if (nh->is_group)
return nh_notifier_grp_info_init(info, nh);
else
return nh_notifier_single_info_init(info, nh);
}
static void nh_notifier_info_fini(struct nh_notifier_info *info,
const struct nexthop *nh)
{
if (nh->is_group)
nh_notifier_grp_info_fini(info, nh);
else
nh_notifier_single_info_fini(info);
}
static int call_nexthop_notifiers(struct net *net,
enum nexthop_event_type event_type,
struct nexthop *nh,
struct netlink_ext_ack *extack)
{
struct nh_notifier_info info = {
.net = net,
.extack = extack,
};
int err;
ASSERT_RTNL();
if (nexthop_notifiers_is_empty(net))
return 0;
err = nh_notifier_info_init(&info, nh);
if (err) {
NL_SET_ERR_MSG(extack, "Failed to initialize nexthop notifier info");
return err;
}
err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
event_type, &info);
nh_notifier_info_fini(&info, nh);
return notifier_to_errno(err);
}
/* There are three users of RES_TABLE, and NHs etc. referenced from there:
*
* 1) a collection of callbacks for NH maintenance. This operates under
* RTNL,
* 2) the delayed work that gradually balances the resilient table,
* 3) and nexthop_select_path(), operating under RCU.
*
* Both the delayed work and the RTNL block are writers, and need to
* maintain mutual exclusion. Since there are only two and well-known
* writers for each table, the RTNL code can make sure it has exclusive
* access thus:
*
* - Have the DW operate without locking;
* - synchronously cancel the DW;
* - do the writing;
* - if the write was not actually a delete, call upkeep, which schedules
* DW again if necessary.
*
* The functions that are always called from the RTNL context use
* rtnl_dereference(). The functions that can also be called from the DW do
* a raw dereference and rely on the above mutual exclusion scheme.
*/
#define nh_res_dereference(p) (rcu_dereference_raw(p))
static int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
enum nexthop_event_type event_type,
struct nexthop *nh,
struct netlink_ext_ack *extack)
{
struct nh_notifier_info info = {
.net = net,
.extack = extack,
};
int err;
err = nh_notifier_info_init(&info, nh);
if (err)
return err;
err = nb->notifier_call(nb, event_type, &info);
nh_notifier_info_fini(&info, nh);
return notifier_to_errno(err);
}
static unsigned int nh_dev_hashfn(unsigned int val)
{
unsigned int mask = NH_DEV_HASHSIZE - 1;
return (val ^
(val >> NH_DEV_HASHBITS) ^
(val >> (NH_DEV_HASHBITS * 2))) & mask;
}
static void nexthop_devhash_add(struct net *net, struct nh_info *nhi)
{
struct net_device *dev = nhi->fib_nhc.nhc_dev;
struct hlist_head *head;
unsigned int hash;
WARN_ON(!dev);
hash = nh_dev_hashfn(dev->ifindex);
head = &net->nexthop.devhash[hash];
hlist_add_head(&nhi->dev_hash, head);
}
static void nexthop_free_group(struct nexthop *nh)
{
struct nh_group *nhg;
int i;
nhg = rcu_dereference_raw(nh->nh_grp);
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
WARN_ON(!list_empty(&nhge->nh_list));
nexthop_put(nhge->nh);
}
WARN_ON(nhg->spare == nhg);
if (nhg->resilient)
vfree(rcu_dereference_raw(nhg->res_table));
kfree(nhg->spare);
kfree(nhg);
}
static void nexthop_free_single(struct nexthop *nh)
{
struct nh_info *nhi;
nhi = rcu_dereference_raw(nh->nh_info);
switch (nhi->family) {
case AF_INET:
fib_nh_release(nh->net, &nhi->fib_nh);
break;
case AF_INET6:
ipv6_stub->fib6_nh_release(&nhi->fib6_nh);
break;
}
kfree(nhi);
}
void nexthop_free_rcu(struct rcu_head *head)
{
struct nexthop *nh = container_of(head, struct nexthop, rcu);
if (nh->is_group)
nexthop_free_group(nh);
else
nexthop_free_single(nh);
kfree(nh);
}
EXPORT_SYMBOL_GPL(nexthop_free_rcu);
static struct nexthop *nexthop_alloc(void)
{
struct nexthop *nh;
nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
if (nh) {
INIT_LIST_HEAD(&nh->fi_list);
INIT_LIST_HEAD(&nh->f6i_list);
INIT_LIST_HEAD(&nh->grp_list);
INIT_LIST_HEAD(&nh->fdb_list);
}
return nh;
}
static struct nh_group *nexthop_grp_alloc(u16 num_nh)
{
struct nh_group *nhg;
nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL);
if (nhg)
nhg->num_nh = num_nh;
return nhg;
}
static void nh_res_table_upkeep_dw(struct work_struct *work);
static struct nh_res_table *
nexthop_res_table_alloc(struct net *net, u32 nhg_id, struct nh_config *cfg)
{
const u16 num_nh_buckets = cfg->nh_grp_res_num_buckets;
struct nh_res_table *res_table;
unsigned long size;
size = struct_size(res_table, nh_buckets, num_nh_buckets);
res_table = __vmalloc(size, GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
if (!res_table)
return NULL;
res_table->net = net;
res_table->nhg_id = nhg_id;
INIT_DELAYED_WORK(&res_table->upkeep_dw, &nh_res_table_upkeep_dw);
INIT_LIST_HEAD(&res_table->uw_nh_entries);
res_table->idle_timer = cfg->nh_grp_res_idle_timer;
res_table->unbalanced_timer = cfg->nh_grp_res_unbalanced_timer;
res_table->num_nh_buckets = num_nh_buckets;
return res_table;
}
static void nh_base_seq_inc(struct net *net)
{
while (++net->nexthop.seq == 0)
;
}
/* no reference taken; rcu lock or rtnl must be held */
struct nexthop *nexthop_find_by_id(struct net *net, u32 id)
{
struct rb_node **pp, *parent = NULL, *next;
pp = &net->nexthop.rb_root.rb_node;
while (1) {
struct nexthop *nh;
next = rcu_dereference_raw(*pp);
if (!next)
break;
parent = next;
nh = rb_entry(parent, struct nexthop, rb_node);
if (id < nh->id)
pp = &next->rb_left;
else if (id > nh->id)
pp = &next->rb_right;
else
return nh;
}
return NULL;
}
EXPORT_SYMBOL_GPL(nexthop_find_by_id);
/* used for auto id allocation; called with rtnl held */
static u32 nh_find_unused_id(struct net *net)
{
u32 id_start = net->nexthop.last_id_allocated;
while (1) {
net->nexthop.last_id_allocated++;
if (net->nexthop.last_id_allocated == id_start)
break;
if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated))
return net->nexthop.last_id_allocated;
}
return 0;
}
static void nh_res_time_set_deadline(unsigned long next_time,
unsigned long *deadline)
{
if (time_before(next_time, *deadline))
*deadline = next_time;
}
static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
{
struct nexthop_grp *p;
size_t len = nhg->num_nh * sizeof(*p);
struct nlattr *nla;
u16 group_type = 0;
int i;
if (nhg->mpath)
group_type = NEXTHOP_GRP_TYPE_MPATH;
if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type))
goto nla_put_failure;
nla = nla_reserve(skb, NHA_GROUP, len);
if (!nla)
goto nla_put_failure;
p = nla_data(nla);
for (i = 0; i < nhg->num_nh; ++i) {
p->id = nhg->nh_entries[i].nh->id;
p->weight = nhg->nh_entries[i].weight - 1;
p += 1;
}
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
int event, u32 portid, u32 seq, unsigned int nlflags)
{
struct fib6_nh *fib6_nh;
struct fib_nh *fib_nh;
struct nlmsghdr *nlh;
struct nh_info *nhi;
struct nhmsg *nhm;
nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
if (!nlh)
return -EMSGSIZE;
nhm = nlmsg_data(nlh);
nhm->nh_family = AF_UNSPEC;
nhm->nh_flags = nh->nh_flags;
nhm->nh_protocol = nh->protocol;
nhm->nh_scope = 0;
nhm->resvd = 0;
if (nla_put_u32(skb, NHA_ID, nh->id))
goto nla_put_failure;
if (nh->is_group) {
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
if (nhg->fdb_nh && nla_put_flag(skb, NHA_FDB))
goto nla_put_failure;
if (nla_put_nh_group(skb, nhg))
goto nla_put_failure;
goto out;
}
nhi = rtnl_dereference(nh->nh_info);
nhm->nh_family = nhi->family;
if (nhi->reject_nh) {
if (nla_put_flag(skb, NHA_BLACKHOLE))
goto nla_put_failure;
goto out;
} else if (nhi->fdb_nh) {
if (nla_put_flag(skb, NHA_FDB))
goto nla_put_failure;
} else {
const struct net_device *dev;
dev = nhi->fib_nhc.nhc_dev;
if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex))
goto nla_put_failure;
}
nhm->nh_scope = nhi->fib_nhc.nhc_scope;
switch (nhi->family) {
case AF_INET:
fib_nh = &nhi->fib_nh;
if (fib_nh->fib_nh_gw_family &&
nla_put_be32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4))
goto nla_put_failure;
break;
case AF_INET6:
fib6_nh = &nhi->fib6_nh;
if (fib6_nh->fib_nh_gw_family &&
nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6))
goto nla_put_failure;
break;
}
if (nhi->fib_nhc.nhc_lwtstate &&
lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate,
NHA_ENCAP, NHA_ENCAP_TYPE) < 0)
goto nla_put_failure;
out:
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static size_t nh_nlmsg_size_grp(struct nexthop *nh)
{
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh;
return nla_total_size(sz) +
nla_total_size(2); /* NHA_GROUP_TYPE */
}
static size_t nh_nlmsg_size_single(struct nexthop *nh)
{
struct nh_info *nhi = rtnl_dereference(nh->nh_info);
size_t sz;
/* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE
* are mutually exclusive
*/
sz = nla_total_size(4); /* NHA_OIF */
switch (nhi->family) {
case AF_INET:
if (nhi->fib_nh.fib_nh_gw_family)
sz += nla_total_size(4); /* NHA_GATEWAY */
break;
case AF_INET6:
/* NHA_GATEWAY */
if (nhi->fib6_nh.fib_nh_gw_family)
sz += nla_total_size(sizeof(const struct in6_addr));
break;
}
if (nhi->fib_nhc.nhc_lwtstate) {
sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate);
sz += nla_total_size(2); /* NHA_ENCAP_TYPE */
}
return sz;
}
static size_t nh_nlmsg_size(struct nexthop *nh)
{
size_t sz = NLMSG_ALIGN(sizeof(struct nhmsg));
sz += nla_total_size(4); /* NHA_ID */
if (nh->is_group)
sz += nh_nlmsg_size_grp(nh);
else
sz += nh_nlmsg_size_single(nh);
return sz;
}
static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info)
{
unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0;
u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
struct sk_buff *skb;
int err = -ENOBUFS;
skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any());
if (!skb)
goto errout;
err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags);
if (err < 0) {
/* -EMSGSIZE implies BUG in nh_nlmsg_size() */
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto errout;
}
rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP,
info->nlh, gfp_any());
return;
errout:
if (err < 0)
rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err);
}
static unsigned long nh_res_bucket_used_time(const struct nh_res_bucket *bucket)
{
return (unsigned long)atomic_long_read(&bucket->used_time);
}
static unsigned long
nh_res_bucket_idle_point(const struct nh_res_table *res_table,
const struct nh_res_bucket *bucket,
unsigned long now)
{
unsigned long time = nh_res_bucket_used_time(bucket);
/* Bucket was not used since it was migrated. The idle time is now. */
if (time == bucket->migrated_time)
return now;
return time + res_table->idle_timer;
}
static unsigned long
nh_res_table_unb_point(const struct nh_res_table *res_table)
{
return res_table->unbalanced_since + res_table->unbalanced_timer;
}
static void nh_res_bucket_set_idle(const struct nh_res_table *res_table,
struct nh_res_bucket *bucket)
{
unsigned long now = jiffies;
atomic_long_set(&bucket->used_time, (long)now);
bucket->migrated_time = now;
}
static void nh_res_bucket_set_busy(struct nh_res_bucket *bucket)
{
atomic_long_set(&bucket->used_time, (long)jiffies);
}
static bool valid_group_nh(struct nexthop *nh, unsigned int npaths,
bool *is_fdb, struct netlink_ext_ack *extack)
{
if (nh->is_group) {
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
/* Nesting groups within groups is not supported. */
if (nhg->mpath) {
NL_SET_ERR_MSG(extack,
"Multipath group can not be a nexthop within a group");
return false;
}
if (nhg->resilient) {
NL_SET_ERR_MSG(extack,
"Resilient group can not be a nexthop within a group");
return false;
}
*is_fdb = nhg->fdb_nh;
} else {
struct nh_info *nhi = rtnl_dereference(nh->nh_info);
if (nhi->reject_nh && npaths > 1) {
NL_SET_ERR_MSG(extack,
"Blackhole nexthop can not be used in a group with more than 1 path");
return false;
}
*is_fdb = nhi->fdb_nh;
}
return true;
}
static int nh_check_attr_fdb_group(struct nexthop *nh, u8 *nh_family,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
nhi = rtnl_dereference(nh->nh_info);
if (!nhi->fdb_nh) {
NL_SET_ERR_MSG(extack, "FDB nexthop group can only have fdb nexthops");
return -EINVAL;
}
if (*nh_family == AF_UNSPEC) {
*nh_family = nhi->family;
} else if (*nh_family != nhi->family) {
NL_SET_ERR_MSG(extack, "FDB nexthop group cannot have mixed family nexthops");
return -EINVAL;
}
return 0;
}
static int nh_check_attr_group(struct net *net,
struct nlattr *tb[], size_t tb_size,
struct netlink_ext_ack *extack)
{
unsigned int len = nla_len(tb[NHA_GROUP]);
u8 nh_family = AF_UNSPEC;
struct nexthop_grp *nhg;
unsigned int i, j;
u8 nhg_fdb = 0;
if (!len || len & (sizeof(struct nexthop_grp) - 1)) {
NL_SET_ERR_MSG(extack,
"Invalid length for nexthop group attribute");
return -EINVAL;
}
/* convert len to number of nexthop ids */
len /= sizeof(*nhg);
nhg = nla_data(tb[NHA_GROUP]);
for (i = 0; i < len; ++i) {
if (nhg[i].resvd1 || nhg[i].resvd2) {
NL_SET_ERR_MSG(extack, "Reserved fields in nexthop_grp must be 0");
return -EINVAL;
}
if (nhg[i].weight > 254) {
NL_SET_ERR_MSG(extack, "Invalid value for weight");
return -EINVAL;
}
for (j = i + 1; j < len; ++j) {
if (nhg[i].id == nhg[j].id) {
NL_SET_ERR_MSG(extack, "Nexthop id can not be used twice in a group");
return -EINVAL;
}
}
}
if (tb[NHA_FDB])
nhg_fdb = 1;
nhg = nla_data(tb[NHA_GROUP]);
for (i = 0; i < len; ++i) {
struct nexthop *nh;
bool is_fdb_nh;
nh = nexthop_find_by_id(net, nhg[i].id);
if (!nh) {
NL_SET_ERR_MSG(extack, "Invalid nexthop id");
return -EINVAL;
}
if (!valid_group_nh(nh, len, &is_fdb_nh, extack))
return -EINVAL;
if (nhg_fdb && nh_check_attr_fdb_group(nh, &nh_family, extack))
return -EINVAL;
if (!nhg_fdb && is_fdb_nh) {
NL_SET_ERR_MSG(extack, "Non FDB nexthop group cannot have fdb nexthops");
return -EINVAL;
}
}
for (i = NHA_GROUP_TYPE + 1; i < tb_size; ++i) {
if (!tb[i])
continue;
if (i == NHA_FDB)
continue;
NL_SET_ERR_MSG(extack,
"No other attributes can be set in nexthop groups");
return -EINVAL;
}
return 0;
}
static bool ipv6_good_nh(const struct fib6_nh *nh)
{
int state = NUD_REACHABLE;
struct neighbour *n;
rcu_read_lock_bh();
n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6);
if (n)
state = n->nud_state;
rcu_read_unlock_bh();
return !!(state & NUD_VALID);
}
static bool ipv4_good_nh(const struct fib_nh *nh)
{
int state = NUD_REACHABLE;
struct neighbour *n;
rcu_read_lock_bh();
n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
(__force u32)nh->fib_nh_gw4);
if (n)
state = n->nud_state;
rcu_read_unlock_bh();
return !!(state & NUD_VALID);
}
static struct nexthop *nexthop_select_path_mp(struct nh_group *nhg, int hash)
{
struct nexthop *rc = NULL;
int i;
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
struct nh_info *nhi;
if (hash > atomic_read(&nhge->mpath.upper_bound))
continue;
nhi = rcu_dereference(nhge->nh->nh_info);
if (nhi->fdb_nh)
return nhge->nh;
/* nexthops always check if it is good and does
* not rely on a sysctl for this behavior
*/
switch (nhi->family) {
case AF_INET:
if (ipv4_good_nh(&nhi->fib_nh))
return nhge->nh;
break;
case AF_INET6:
if (ipv6_good_nh(&nhi->fib6_nh))
return nhge->nh;
break;
}
if (!rc)
rc = nhge->nh;
}
return rc;
}
static struct nexthop *nexthop_select_path_res(struct nh_group *nhg, int hash)
{
struct nh_res_table *res_table = rcu_dereference(nhg->res_table);
u16 bucket_index = hash % res_table->num_nh_buckets;
struct nh_res_bucket *bucket;
struct nh_grp_entry *nhge;
/* nexthop_select_path() is expected to return a non-NULL value, so
* skip protocol validation and just hand out whatever there is.
*/
bucket = &res_table->nh_buckets[bucket_index];
nh_res_bucket_set_busy(bucket);
nhge = rcu_dereference(bucket->nh_entry);
return nhge->nh;
}
struct nexthop *nexthop_select_path(struct nexthop *nh, int hash)
{
struct nh_group *nhg;
if (!nh->is_group)
return nh;
nhg = rcu_dereference(nh->nh_grp);
if (nhg->mpath)
return nexthop_select_path_mp(nhg, hash);
else if (nhg->resilient)
return nexthop_select_path_res(nhg, hash);
/* Unreachable. */
return NULL;
}
EXPORT_SYMBOL_GPL(nexthop_select_path);
int nexthop_for_each_fib6_nh(struct nexthop *nh,
int (*cb)(struct fib6_nh *nh, void *arg),
void *arg)
{
struct nh_info *nhi;
int err;
if (nh->is_group) {
struct nh_group *nhg;
int i;
nhg = rcu_dereference_rtnl(nh->nh_grp);
for (i = 0; i < nhg->num_nh; i++) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
nhi = rcu_dereference_rtnl(nhge->nh->nh_info);
err = cb(&nhi->fib6_nh, arg);
if (err)
return err;
}
} else {
nhi = rcu_dereference_rtnl(nh->nh_info);
err = cb(&nhi->fib6_nh, arg);
if (err)
return err;
}
return 0;
}
EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh);
static int check_src_addr(const struct in6_addr *saddr,
struct netlink_ext_ack *extack)
{
if (!ipv6_addr_any(saddr)) {
NL_SET_ERR_MSG(extack, "IPv6 routes using source address can not use nexthop objects");
return -EINVAL;
}
return 0;
}
int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
bool is_fdb_nh;
/* fib6_src is unique to a fib6_info and limits the ability to cache
* routes in fib6_nh within a nexthop that is potentially shared
* across multiple fib entries. If the config wants to use source
* routing it can not use nexthop objects. mlxsw also does not allow
* fib6_src on routes.
*/
if (cfg && check_src_addr(&cfg->fc_src, extack) < 0)
return -EINVAL;
if (nh->is_group) {
struct nh_group *nhg;
nhg = rtnl_dereference(nh->nh_grp);
if (nhg->has_v4)
goto no_v4_nh;
is_fdb_nh = nhg->fdb_nh;
} else {
nhi = rtnl_dereference(nh->nh_info);
if (nhi->family == AF_INET)
goto no_v4_nh;
is_fdb_nh = nhi->fdb_nh;
}
if (is_fdb_nh) {
NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
return -EINVAL;
}
return 0;
no_v4_nh:
NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop");
return -EINVAL;
}
EXPORT_SYMBOL_GPL(fib6_check_nexthop);
/* if existing nexthop has ipv6 routes linked to it, need
* to verify this new spec works with ipv6
*/
static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new,
struct netlink_ext_ack *extack)
{
struct fib6_info *f6i;
if (list_empty(&old->f6i_list))
return 0;
list_for_each_entry(f6i, &old->f6i_list, nh_list) {
if (check_src_addr(&f6i->fib6_src.addr, extack) < 0)
return -EINVAL;
}
return fib6_check_nexthop(new, NULL, extack);
}
static int nexthop_check_scope(struct nh_info *nhi, u8 scope,
struct netlink_ext_ack *extack)
{
if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {
NL_SET_ERR_MSG(extack,
"Route with host scope can not have a gateway");
return -EINVAL;
}
if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {
NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");
return -EINVAL;
}
return 0;
}
/* Invoked by fib add code to verify nexthop by id is ok with
* config for prefix; parts of fib_check_nh not done when nexthop
* object is used.
*/
int fib_check_nexthop(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
int err = 0;
if (nh->is_group) {
struct nh_group *nhg;
nhg = rtnl_dereference(nh->nh_grp);
if (nhg->fdb_nh) {
NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
err = -EINVAL;
goto out;
}
if (scope == RT_SCOPE_HOST) {
NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");
err = -EINVAL;
goto out;
}
/* all nexthops in a group have the same scope */
nhi = rtnl_dereference(nhg->nh_entries[0].nh->nh_info);
err = nexthop_check_scope(nhi, scope, extack);
} else {
nhi = rtnl_dereference(nh->nh_info);
if (nhi->fdb_nh) {
NL_SET_ERR_MSG(extack, "Route cannot point to a fdb nexthop");
err = -EINVAL;
goto out;
}
err = nexthop_check_scope(nhi, scope, extack);
}
out:
return err;
}
static int fib_check_nh_list(struct nexthop *old, struct nexthop *new,
struct netlink_ext_ack *extack)
{
struct fib_info *fi;
list_for_each_entry(fi, &old->fi_list, nh_list) {
int err;
err = fib_check_nexthop(new, fi->fib_scope, extack);
if (err)
return err;
}
return 0;
}
static bool nh_res_nhge_is_balanced(const struct nh_grp_entry *nhge)
{
return nhge->res.count_buckets == nhge->res.wants_buckets;
}
static bool nh_res_nhge_is_ow(const struct nh_grp_entry *nhge)
{
return nhge->res.count_buckets > nhge->res.wants_buckets;
}
static bool nh_res_nhge_is_uw(const struct nh_grp_entry *nhge)
{
return nhge->res.count_buckets < nhge->res.wants_buckets;
}
static bool nh_res_table_is_balanced(const struct nh_res_table *res_table)
{
return list_empty(&res_table->uw_nh_entries);
}
static void nh_res_bucket_unset_nh(struct nh_res_bucket *bucket)
{
struct nh_grp_entry *nhge;
if (bucket->occupied) {
nhge = nh_res_dereference(bucket->nh_entry);
nhge->res.count_buckets--;
bucket->occupied = false;
}
}
static void nh_res_bucket_set_nh(struct nh_res_bucket *bucket,
struct nh_grp_entry *nhge)
{
nh_res_bucket_unset_nh(bucket);
bucket->occupied = true;
rcu_assign_pointer(bucket->nh_entry, nhge);
nhge->res.count_buckets++;
}
static bool nh_res_bucket_should_migrate(struct nh_res_table *res_table,
struct nh_res_bucket *bucket,
unsigned long *deadline, bool *force)
{
unsigned long now = jiffies;
struct nh_grp_entry *nhge;
unsigned long idle_point;
if (!bucket->occupied) {
/* The bucket is not occupied, its NHGE pointer is either
* NULL or obsolete. We _have to_ migrate: set force.
*/
*force = true;
return true;
}
nhge = nh_res_dereference(bucket->nh_entry);
/* If the bucket is populated by an underweight or balanced
* nexthop, do not migrate.
*/
if (!nh_res_nhge_is_ow(nhge))
return false;
/* At this point we know that the bucket is populated with an
* overweight nexthop. It needs to be migrated to a new nexthop if
* the idle timer of unbalanced timer expired.
*/
idle_point = nh_res_bucket_idle_point(res_table, bucket, now);
if (time_after_eq(now, idle_point)) {
/* The bucket is idle. We _can_ migrate: unset force. */
*force = false;
return true;
}
/* Unbalanced timer of 0 means "never force". */
if (res_table->unbalanced_timer) {
unsigned long unb_point;
unb_point = nh_res_table_unb_point(res_table);
if (time_after(now, unb_point)) {
/* The bucket is not idle, but the unbalanced timer
* expired. We _can_ migrate, but set force anyway,
* so that drivers know to ignore activity reports
* from the HW.
*/
*force = true;
return true;
}
nh_res_time_set_deadline(unb_point, deadline);
}
nh_res_time_set_deadline(idle_point, deadline);
return false;
}
static bool nh_res_bucket_migrate(struct nh_res_table *res_table,
u16 bucket_index, bool force)
{
struct nh_res_bucket *bucket = &res_table->nh_buckets[bucket_index];
struct nh_grp_entry *new_nhge;
new_nhge = list_first_entry_or_null(&res_table->uw_nh_entries,
struct nh_grp_entry,
res.uw_nh_entry);
if (WARN_ON_ONCE(!new_nhge))
/* If this function is called, "bucket" is either not
* occupied, or it belongs to a next hop that is
* overweight. In either case, there ought to be a
* corresponding underweight next hop.
*/
return false;
nh_res_bucket_set_nh(bucket, new_nhge);
nh_res_bucket_set_idle(res_table, bucket);
if (nh_res_nhge_is_balanced(new_nhge))
list_del(&new_nhge->res.uw_nh_entry);
return true;
}
#define NH_RES_UPKEEP_DW_MINIMUM_INTERVAL (HZ / 2)
static void nh_res_table_upkeep(struct nh_res_table *res_table)
{
unsigned long now = jiffies;
unsigned long deadline;
u16 i;
/* Deadline is the next time that upkeep should be run. It is the
* earliest time at which one of the buckets might be migrated.
* Start at the most pessimistic estimate: either unbalanced_timer
* from now, or if there is none, idle_timer from now. For each
* encountered time point, call nh_res_time_set_deadline() to
* refine the estimate.
*/
if (res_table->unbalanced_timer)
deadline = now + res_table->unbalanced_timer;
else
deadline = now + res_table->idle_timer;
for (i = 0; i < res_table->num_nh_buckets; i++) {
struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
bool force;
if (nh_res_bucket_should_migrate(res_table, bucket,
&deadline, &force)) {
if (!nh_res_bucket_migrate(res_table, i, force)) {
unsigned long idle_point;
/* A driver can override the migration
* decision if the HW reports that the
* bucket is actually not idle. Therefore
* remark the bucket as busy again and
* update the deadline.
*/
nh_res_bucket_set_busy(bucket);
idle_point = nh_res_bucket_idle_point(res_table,
bucket,
now);
nh_res_time_set_deadline(idle_point, &deadline);
}
}
}
/* If the group is still unbalanced, schedule the next upkeep to
* either the deadline computed above, or the minimum deadline,
* whichever comes later.
*/
if (!nh_res_table_is_balanced(res_table)) {
unsigned long now = jiffies;
unsigned long min_deadline;
min_deadline = now + NH_RES_UPKEEP_DW_MINIMUM_INTERVAL;
if (time_before(deadline, min_deadline))
deadline = min_deadline;
queue_delayed_work(system_power_efficient_wq,
&res_table->upkeep_dw, deadline - now);
}
}
static void nh_res_table_upkeep_dw(struct work_struct *work)
{
struct delayed_work *dw = to_delayed_work(work);
struct nh_res_table *res_table;
res_table = container_of(dw, struct nh_res_table, upkeep_dw);
nh_res_table_upkeep(res_table);
}
static void nh_res_table_cancel_upkeep(struct nh_res_table *res_table)
{
cancel_delayed_work_sync(&res_table->upkeep_dw);
}
static void nh_res_group_rebalance(struct nh_group *nhg,
struct nh_res_table *res_table)
{
int prev_upper_bound = 0;
int total = 0;
int w = 0;
int i;
INIT_LIST_HEAD(&res_table->uw_nh_entries);
for (i = 0; i < nhg->num_nh; ++i)
total += nhg->nh_entries[i].weight;
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
int upper_bound;
w += nhge->weight;
upper_bound = DIV_ROUND_CLOSEST(res_table->num_nh_buckets * w,
total);
nhge->res.wants_buckets = upper_bound - prev_upper_bound;
prev_upper_bound = upper_bound;
if (nh_res_nhge_is_uw(nhge)) {
if (list_empty(&res_table->uw_nh_entries))
res_table->unbalanced_since = jiffies;
list_add(&nhge->res.uw_nh_entry,
&res_table->uw_nh_entries);
}
}
}
/* Migrate buckets in res_table so that they reference NHGE's from NHG with
* the right NH ID. Set those buckets that do not have a corresponding NHGE
* entry in NHG as not occupied.
*/
static void nh_res_table_migrate_buckets(struct nh_res_table *res_table,
struct nh_group *nhg)
{
u16 i;
for (i = 0; i < res_table->num_nh_buckets; i++) {
struct nh_res_bucket *bucket = &res_table->nh_buckets[i];
u32 id = rtnl_dereference(bucket->nh_entry)->nh->id;
bool found = false;
int j;
for (j = 0; j < nhg->num_nh; j++) {
struct nh_grp_entry *nhge = &nhg->nh_entries[j];
if (nhge->nh->id == id) {
nh_res_bucket_set_nh(bucket, nhge);
found = true;
break;
}
}
if (!found)
nh_res_bucket_unset_nh(bucket);
}
}
static void replace_nexthop_grp_res(struct nh_group *oldg,
struct nh_group *newg)
{
/* For NH group replacement, the new NHG might only have a stub
* hash table with 0 buckets, because the number of buckets was not
* specified. For NH removal, oldg and newg both reference the same
* res_table. So in any case, in the following, we want to work
* with oldg->res_table.
*/
struct nh_res_table *old_res_table = rtnl_dereference(oldg->res_table);
unsigned long prev_unbalanced_since = old_res_table->unbalanced_since;
bool prev_has_uw = !list_empty(&old_res_table->uw_nh_entries);
nh_res_table_cancel_upkeep(old_res_table);
nh_res_table_migrate_buckets(old_res_table, newg);
nh_res_group_rebalance(newg, old_res_table);
if (prev_has_uw && !list_empty(&old_res_table->uw_nh_entries))
old_res_table->unbalanced_since = prev_unbalanced_since;
nh_res_table_upkeep(old_res_table);
}
static void nh_mp_group_rebalance(struct nh_group *nhg)
{
int total = 0;
int w = 0;
int i;
for (i = 0; i < nhg->num_nh; ++i)
total += nhg->nh_entries[i].weight;
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
int upper_bound;
w += nhge->weight;
upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1;
atomic_set(&nhge->mpath.upper_bound, upper_bound);
}
}
static void remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge,
struct nl_info *nlinfo)
{
struct nh_grp_entry *nhges, *new_nhges;
struct nexthop *nhp = nhge->nh_parent;
struct netlink_ext_ack extack;
struct nexthop *nh = nhge->nh;
struct nh_group *nhg, *newg;
int i, j, err;
WARN_ON(!nh);
nhg = rtnl_dereference(nhp->nh_grp);
newg = nhg->spare;
/* last entry, keep it visible and remove the parent */
if (nhg->num_nh == 1) {
remove_nexthop(net, nhp, nlinfo);
return;
}
newg->has_v4 = false;
newg->is_multipath = nhg->is_multipath;
newg->mpath = nhg->mpath;
newg->resilient = nhg->resilient;
newg->fdb_nh = nhg->fdb_nh;
newg->num_nh = nhg->num_nh;
/* copy old entries to new except the one getting removed */
nhges = nhg->nh_entries;
new_nhges = newg->nh_entries;
for (i = 0, j = 0; i < nhg->num_nh; ++i) {
struct nh_info *nhi;
/* current nexthop getting removed */
if (nhg->nh_entries[i].nh == nh) {
newg->num_nh--;
continue;
}
nhi = rtnl_dereference(nhges[i].nh->nh_info);
if (nhi->family == AF_INET)
newg->has_v4 = true;
list_del(&nhges[i].nh_list);
new_nhges[j].nh_parent = nhges[i].nh_parent;
new_nhges[j].nh = nhges[i].nh;
new_nhges[j].weight = nhges[i].weight;
list_add(&new_nhges[j].nh_list, &new_nhges[j].nh->grp_list);
j++;
}
if (newg->mpath)
nh_mp_group_rebalance(newg);
else if (newg->resilient)
replace_nexthop_grp_res(nhg, newg);
rcu_assign_pointer(nhp->nh_grp, newg);
list_del(&nhge->nh_list);
nexthop_put(nhge->nh);
err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, nhp, &extack);
if (err)
pr_err("%s\n", extack._msg);
if (nlinfo)
nexthop_notify(RTM_NEWNEXTHOP, nhp, nlinfo);
}
static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
struct nh_grp_entry *nhge, *tmp;
list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list)
remove_nh_grp_entry(net, nhge, nlinfo);
/* make sure all see the newly published array before releasing rtnl */
synchronize_net();
}
static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo)
{
struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
struct nh_res_table *res_table;
int i, num_nh = nhg->num_nh;
for (i = 0; i < num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
if (WARN_ON(!nhge->nh))
continue;
list_del_init(&nhge->nh_list);
}
if (nhg->resilient) {
res_table = rtnl_dereference(nhg->res_table);
nh_res_table_cancel_upkeep(res_table);
}
}
/* not called for nexthop replace */
static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
{
struct fib6_info *f6i, *tmp;
bool do_flush = false;
struct fib_info *fi;
list_for_each_entry(fi, &nh->fi_list, nh_list) {
fi->fib_flags |= RTNH_F_DEAD;
do_flush = true;
}
if (do_flush)
fib_flush(net);
/* ip6_del_rt removes the entry from this list hence the _safe */
list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) {
/* __ip6_del_rt does a release, so do a hold here */
fib6_info_hold(f6i);
ipv6_stub->ip6_del_rt(net, f6i,
!net->ipv4.sysctl_nexthop_compat_mode);
}
}
static void __remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
__remove_nexthop_fib(net, nh);
if (nh->is_group) {
remove_nexthop_group(nh, nlinfo);
} else {
struct nh_info *nhi;
nhi = rtnl_dereference(nh->nh_info);
if (nhi->fib_nhc.nhc_dev)
hlist_del(&nhi->dev_hash);
remove_nexthop_from_groups(net, nh, nlinfo);
}
}
static void remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh, NULL);
/* remove from the tree */
rb_erase(&nh->rb_node, &net->nexthop.rb_root);
if (nlinfo)
nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
__remove_nexthop(net, nh, nlinfo);
nh_base_seq_inc(net);
nexthop_put(nh);
}
/* if any FIB entries reference this nexthop, any dst entries
* need to be regenerated
*/
static void nh_rt_cache_flush(struct net *net, struct nexthop *nh)
{
struct fib6_info *f6i;
if (!list_empty(&nh->fi_list))
rt_cache_flush(net);
list_for_each_entry(f6i, &nh->f6i_list, nh_list)
ipv6_stub->fib6_update_sernum(net, f6i);
}
static int replace_nexthop_grp(struct net *net, struct nexthop *old,
struct nexthop *new, const struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nh_res_table *tmp_table = NULL;
struct nh_res_table *new_res_table;
struct nh_res_table *old_res_table;
struct nh_group *oldg, *newg;
int i, err;
if (!new->is_group) {
NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a nexthop.");
return -EINVAL;
}
oldg = rtnl_dereference(old->nh_grp);
newg = rtnl_dereference(new->nh_grp);
if (newg->mpath != oldg->mpath) {
NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with one of a different type.");
return -EINVAL;
}
if (newg->mpath) {
err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new,
extack);
if (err)
return err;
} else if (newg->resilient) {
new_res_table = rtnl_dereference(newg->res_table);
old_res_table = rtnl_dereference(oldg->res_table);
/* Accept if num_nh_buckets was not given, but if it was
* given, demand that the value be correct.
*/
if (cfg->nh_grp_res_has_num_buckets &&
cfg->nh_grp_res_num_buckets !=
old_res_table->num_nh_buckets) {
NL_SET_ERR_MSG(extack, "Can not change number of buckets of a resilient nexthop group.");
return -EINVAL;
}
if (cfg->nh_grp_res_has_idle_timer)
old_res_table->idle_timer = cfg->nh_grp_res_idle_timer;
if (cfg->nh_grp_res_has_unbalanced_timer)
old_res_table->unbalanced_timer =
cfg->nh_grp_res_unbalanced_timer;
replace_nexthop_grp_res(oldg, newg);
tmp_table = new_res_table;
rcu_assign_pointer(newg->res_table, old_res_table);
rcu_assign_pointer(newg->spare->res_table, old_res_table);
}
/* update parents - used by nexthop code for cleanup */
for (i = 0; i < newg->num_nh; i++)
newg->nh_entries[i].nh_parent = old;
rcu_assign_pointer(old->nh_grp, newg);
if (newg->resilient) {
rcu_assign_pointer(oldg->res_table, tmp_table);
rcu_assign_pointer(oldg->spare->res_table, tmp_table);
}
for (i = 0; i < oldg->num_nh; i++)
oldg->nh_entries[i].nh_parent = new;
rcu_assign_pointer(new->nh_grp, oldg);
return 0;
}
static void nh_group_v4_update(struct nh_group *nhg)
{
struct nh_grp_entry *nhges;
bool has_v4 = false;
int i;
nhges = nhg->nh_entries;
for (i = 0; i < nhg->num_nh; i++) {
struct nh_info *nhi;
nhi = rtnl_dereference(nhges[i].nh->nh_info);
if (nhi->family == AF_INET)
has_v4 = true;
}
nhg->has_v4 = has_v4;
}
static int replace_nexthop_single(struct net *net, struct nexthop *old,
struct nexthop *new,
struct netlink_ext_ack *extack)
{
u8 old_protocol, old_nh_flags;
struct nh_info *oldi, *newi;
struct nh_grp_entry *nhge;
int err;
if (new->is_group) {
NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a nexthop group.");
return -EINVAL;
}
err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new, extack);
if (err)
return err;
/* Hardware flags were set on 'old' as 'new' is not in the red-black
* tree. Therefore, inherit the flags from 'old' to 'new'.
*/
new->nh_flags |= old->nh_flags & (RTNH_F_OFFLOAD | RTNH_F_TRAP);
oldi = rtnl_dereference(old->nh_info);
newi = rtnl_dereference(new->nh_info);
newi->nh_parent = old;
oldi->nh_parent = new;
old_protocol = old->protocol;
old_nh_flags = old->nh_flags;
old->protocol = new->protocol;
old->nh_flags = new->nh_flags;
rcu_assign_pointer(old->nh_info, newi);
rcu_assign_pointer(new->nh_info, oldi);
/* Send a replace notification for all the groups using the nexthop. */
list_for_each_entry(nhge, &old->grp_list, nh_list) {
struct nexthop *nhp = nhge->nh_parent;
err = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, nhp,
extack);
if (err)
goto err_notify;
}
/* When replacing an IPv4 nexthop with an IPv6 nexthop, potentially
* update IPv4 indication in all the groups using the nexthop.
*/
if (oldi->family == AF_INET && newi->family == AF_INET6) {
list_for_each_entry(nhge, &old->grp_list, nh_list) {
struct nexthop *nhp = nhge->nh_parent;
struct nh_group *nhg;
nhg = rtnl_dereference(nhp->nh_grp);
nh_group_v4_update(nhg);
}
}
return 0;
err_notify:
rcu_assign_pointer(new->nh_info, newi);
rcu_assign_pointer(old->nh_info, oldi);
old->nh_flags = old_nh_flags;
old->protocol = old_protocol;
oldi->nh_parent = old;
newi->nh_parent = new;
list_for_each_entry_continue_reverse(nhge, &old->grp_list, nh_list) {
struct nexthop *nhp = nhge->nh_parent;
call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, nhp, extack);
}
call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, old, extack);
return err;
}
static void __nexthop_replace_notify(struct net *net, struct nexthop *nh,
struct nl_info *info)
{
struct fib6_info *f6i;
if (!list_empty(&nh->fi_list)) {
struct fib_info *fi;
/* expectation is a few fib_info per nexthop and then
* a lot of routes per fib_info. So mark the fib_info
* and then walk the fib tables once
*/
list_for_each_entry(fi, &nh->fi_list, nh_list)
fi->nh_updated = true;
fib_info_notify_update(net, info);
list_for_each_entry(fi, &nh->fi_list, nh_list)
fi->nh_updated = false;
}
list_for_each_entry(f6i, &nh->f6i_list, nh_list)
ipv6_stub->fib6_rt_update(net, f6i, info);
}
/* send RTM_NEWROUTE with REPLACE flag set for all FIB entries
* linked to this nexthop and for all groups that the nexthop
* is a member of
*/
static void nexthop_replace_notify(struct net *net, struct nexthop *nh,
struct nl_info *info)
{
struct nh_grp_entry *nhge;
__nexthop_replace_notify(net, nh, info);
list_for_each_entry(nhge, &nh->grp_list, nh_list)
__nexthop_replace_notify(net, nhge->nh_parent, info);
}
static int replace_nexthop(struct net *net, struct nexthop *old,
struct nexthop *new, const struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
bool new_is_reject = false;
struct nh_grp_entry *nhge;
int err;
/* check that existing FIB entries are ok with the
* new nexthop definition
*/
err = fib_check_nh_list(old, new, extack);
if (err)
return err;
err = fib6_check_nh_list(old, new, extack);
if (err)
return err;
if (!new->is_group) {
struct nh_info *nhi = rtnl_dereference(new->nh_info);
new_is_reject = nhi->reject_nh;
}
list_for_each_entry(nhge, &old->grp_list, nh_list) {
/* if new nexthop is a blackhole, any groups using this
* nexthop cannot have more than 1 path
*/
if (new_is_reject &&
nexthop_num_path(nhge->nh_parent) > 1) {
NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a member of a group with more than one path");
return -EINVAL;
}
err = fib_check_nh_list(nhge->nh_parent, new, extack);
if (err)
return err;
err = fib6_check_nh_list(nhge->nh_parent, new, extack);
if (err)
return err;
}
if (old->is_group)
err = replace_nexthop_grp(net, old, new, cfg, extack);
else
err = replace_nexthop_single(net, old, new, extack);
if (!err) {
nh_rt_cache_flush(net, old);
__remove_nexthop(net, new, NULL);
nexthop_put(new);
}
return err;
}
/* called with rtnl_lock held */
static int insert_nexthop(struct net *net, struct nexthop *new_nh,
struct nh_config *cfg, struct netlink_ext_ack *extack)
{
struct rb_node **pp, *parent = NULL, *next;
struct rb_root *root = &net->nexthop.rb_root;
bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
bool create = !!(cfg->nlflags & NLM_F_CREATE);
u32 new_id = new_nh->id;
int replace_notify = 0;
int rc = -EEXIST;
pp = &root->rb_node;
while (1) {
struct nexthop *nh;
next = *pp;
if (!next)
break;
parent = next;
nh = rb_entry(parent, struct nexthop, rb_node);
if (new_id < nh->id) {
pp = &next->rb_left;
} else if (new_id > nh->id) {
pp = &next->rb_right;
} else if (replace) {
rc = replace_nexthop(net, nh, new_nh, cfg, extack);
if (!rc) {
new_nh = nh; /* send notification with old nh */
replace_notify = 1;
}
goto out;
} else {
/* id already exists and not a replace */
goto out;
}
}
if (replace && !create) {
NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists");
rc = -ENOENT;
goto out;
}
if (new_nh->is_group) {
struct nh_group *nhg = rtnl_dereference(new_nh->nh_grp);
struct nh_res_table *res_table;
if (nhg->resilient) {
res_table = rtnl_dereference(nhg->res_table);
/* Not passing the number of buckets is OK when
* replacing, but not when creating a new group.
*/
if (!cfg->nh_grp_res_has_num_buckets) {
NL_SET_ERR_MSG(extack, "Number of buckets not specified for nexthop group insertion");
rc = -EINVAL;
goto out;
}
nh_res_group_rebalance(nhg, res_table);
nh_res_table_upkeep(res_table);
}
}
rb_link_node_rcu(&new_nh->rb_node, parent, pp);
rb_insert_color(&new_nh->rb_node, root);
rc = call_nexthop_notifiers(net, NEXTHOP_EVENT_REPLACE, new_nh, extack);
if (rc)
rb_erase(&new_nh->rb_node, &net->nexthop.rb_root);
out:
if (!rc) {
nh_base_seq_inc(net);
nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
if (replace_notify && net->ipv4.sysctl_nexthop_compat_mode)
nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
}
return rc;
}
/* rtnl */
/* remove all nexthops tied to a device being deleted */
static void nexthop_flush_dev(struct net_device *dev, unsigned long event)
{
unsigned int hash = nh_dev_hashfn(dev->ifindex);
struct net *net = dev_net(dev);
struct hlist_head *head = &net->nexthop.devhash[hash];
struct hlist_node *n;
struct nh_info *nhi;
hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
if (nhi->fib_nhc.nhc_dev != dev)
continue;
if (nhi->reject_nh &&
(event == NETDEV_DOWN || event == NETDEV_CHANGE))
continue;
remove_nexthop(net, nhi->nh_parent, NULL);
}
}
/* rtnl; called when net namespace is deleted */
static void flush_all_nexthops(struct net *net)
{
struct rb_root *root = &net->nexthop.rb_root;
struct rb_node *node;
struct nexthop *nh;
while ((node = rb_first(root))) {
nh = rb_entry(node, struct nexthop, rb_node);
remove_nexthop(net, nh, NULL);
cond_resched();
}
}
static struct nexthop *nexthop_create_group(struct net *net,
struct nh_config *cfg)
{
struct nlattr *grps_attr = cfg->nh_grp;
struct nexthop_grp *entry = nla_data(grps_attr);
u16 num_nh = nla_len(grps_attr) / sizeof(*entry);
struct nh_group *nhg;
struct nexthop *nh;
int err;
int i;
if (WARN_ON(!num_nh))
return ERR_PTR(-EINVAL);
nh = nexthop_alloc();
if (!nh)
return ERR_PTR(-ENOMEM);
nh->is_group = 1;
nhg = nexthop_grp_alloc(num_nh);
if (!nhg) {
kfree(nh);
return ERR_PTR(-ENOMEM);
}
/* spare group used for removals */
nhg->spare = nexthop_grp_alloc(num_nh);
if (!nhg->spare) {
kfree(nhg);
kfree(nh);
return ERR_PTR(-ENOMEM);
}
nhg->spare->spare = nhg;
for (i = 0; i < nhg->num_nh; ++i) {
struct nexthop *nhe;
struct nh_info *nhi;
nhe = nexthop_find_by_id(net, entry[i].id);
if (!nexthop_get(nhe)) {
err = -ENOENT;
goto out_no_nh;
}
nhi = rtnl_dereference(nhe->nh_info);
if (nhi->family == AF_INET)
nhg->has_v4 = true;
nhg->nh_entries[i].nh = nhe;
nhg->nh_entries[i].weight = entry[i].weight + 1;
list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list);
nhg->nh_entries[i].nh_parent = nh;
}
if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) {
nhg->mpath = 1;
nhg->is_multipath = true;
} else if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_RES) {
struct nh_res_table *res_table;
/* Bounce resilient groups for now. */
err = -EINVAL;
goto out_no_nh;
res_table = nexthop_res_table_alloc(net, cfg->nh_id, cfg);
if (!res_table) {
err = -ENOMEM;
goto out_no_nh;
}
rcu_assign_pointer(nhg->spare->res_table, res_table);
rcu_assign_pointer(nhg->res_table, res_table);
nhg->resilient = true;
nhg->is_multipath = true;
}
WARN_ON_ONCE(nhg->mpath + nhg->resilient != 1);
if (nhg->mpath)
nh_mp_group_rebalance(nhg);
if (cfg->nh_fdb)
nhg->fdb_nh = 1;
rcu_assign_pointer(nh->nh_grp, nhg);
return nh;
out_no_nh:
for (i--; i >= 0; --i) {
list_del(&nhg->nh_entries[i].nh_list);
nexthop_put(nhg->nh_entries[i].nh);
}
kfree(nhg->spare);
kfree(nhg);
kfree(nh);
return ERR_PTR(err);
}
static int nh_create_ipv4(struct net *net, struct nexthop *nh,
struct nh_info *nhi, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct fib_nh *fib_nh = &nhi->fib_nh;
struct fib_config fib_cfg = {
.fc_oif = cfg->nh_ifindex,
.fc_gw4 = cfg->gw.ipv4,
.fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0,
.fc_flags = cfg->nh_flags,
.fc_encap = cfg->nh_encap,
.fc_encap_type = cfg->nh_encap_type,
};
u32 tb_id = (cfg->dev ? l3mdev_fib_table(cfg->dev) : RT_TABLE_MAIN);
int err;
err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack);
if (err) {
fib_nh_release(net, fib_nh);
goto out;
}
if (nhi->fdb_nh)
goto out;
/* sets nh_dev if successful */
err = fib_check_nh(net, fib_nh, tb_id, 0, extack);
if (!err) {
nh->nh_flags = fib_nh->fib_nh_flags;
fib_info_update_nhc_saddr(net, &fib_nh->nh_common,
fib_nh->fib_nh_scope);
} else {
fib_nh_release(net, fib_nh);
}
out:
return err;
}
static int nh_create_ipv6(struct net *net, struct nexthop *nh,
struct nh_info *nhi, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct fib6_nh *fib6_nh = &nhi->fib6_nh;
struct fib6_config fib6_cfg = {
.fc_table = l3mdev_fib_table(cfg->dev),
.fc_ifindex = cfg->nh_ifindex,
.fc_gateway = cfg->gw.ipv6,
.fc_flags = cfg->nh_flags,
.fc_encap = cfg->nh_encap,
.fc_encap_type = cfg->nh_encap_type,
.fc_is_fdb = cfg->nh_fdb,
};
int err;
if (!ipv6_addr_any(&cfg->gw.ipv6))
fib6_cfg.fc_flags |= RTF_GATEWAY;
/* sets nh_dev if successful */
err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL,
extack);
if (err)
ipv6_stub->fib6_nh_release(fib6_nh);
else
nh->nh_flags = fib6_nh->fib_nh_flags;
return err;
}
static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
struct nexthop *nh;
int err = 0;
nh = nexthop_alloc();
if (!nh)
return ERR_PTR(-ENOMEM);
nhi = kzalloc(sizeof(*nhi), GFP_KERNEL);
if (!nhi) {
kfree(nh);
return ERR_PTR(-ENOMEM);
}
nh->nh_flags = cfg->nh_flags;
nh->net = net;
nhi->nh_parent = nh;
nhi->family = cfg->nh_family;
nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK;
if (cfg->nh_fdb)
nhi->fdb_nh = 1;
if (cfg->nh_blackhole) {
nhi->reject_nh = 1;
cfg->nh_ifindex = net->loopback_dev->ifindex;
}
switch (cfg->nh_family) {
case AF_INET:
err = nh_create_ipv4(net, nh, nhi, cfg, extack);
break;
case AF_INET6:
err = nh_create_ipv6(net, nh, nhi, cfg, extack);
break;
}
if (err) {
kfree(nhi);
kfree(nh);
return ERR_PTR(err);
}
/* add the entry to the device based hash */
if (!nhi->fdb_nh)
nexthop_devhash_add(net, nhi);
rcu_assign_pointer(nh->nh_info, nhi);
return nh;
}
/* called with rtnl lock held */
static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nexthop *nh;
int err;
if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
return ERR_PTR(-EINVAL);
}
if (!cfg->nh_id) {
cfg->nh_id = nh_find_unused_id(net);
if (!cfg->nh_id) {
NL_SET_ERR_MSG(extack, "No unused id");
return ERR_PTR(-EINVAL);
}
}
if (cfg->nh_grp)
nh = nexthop_create_group(net, cfg);
else
nh = nexthop_create(net, cfg, extack);
if (IS_ERR(nh))
return nh;
refcount_set(&nh->refcnt, 1);
nh->id = cfg->nh_id;
nh->protocol = cfg->nh_protocol;
nh->net = net;
err = insert_nexthop(net, nh, cfg, extack);
if (err) {
__remove_nexthop(net, nh, NULL);
nexthop_put(nh);
nh = ERR_PTR(err);
}
return nh;
}
static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nhmsg *nhm = nlmsg_data(nlh);
struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_new)];
int err;
err = nlmsg_parse(nlh, sizeof(*nhm), tb,
ARRAY_SIZE(rtm_nh_policy_new) - 1,
rtm_nh_policy_new, extack);
if (err < 0)
return err;
err = -EINVAL;
if (nhm->resvd || nhm->nh_scope) {
NL_SET_ERR_MSG(extack, "Invalid values in ancillary header");
goto out;
}
if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
goto out;
}
switch (nhm->nh_family) {
case AF_INET:
case AF_INET6:
break;
case AF_UNSPEC:
if (tb[NHA_GROUP])
break;
fallthrough;
default:
NL_SET_ERR_MSG(extack, "Invalid address family");
goto out;
}
memset(cfg, 0, sizeof(*cfg));
cfg->nlflags = nlh->nlmsg_flags;
cfg->nlinfo.portid = NETLINK_CB(skb).portid;
cfg->nlinfo.nlh = nlh;
cfg->nlinfo.nl_net = net;
cfg->nh_family = nhm->nh_family;
cfg->nh_protocol = nhm->nh_protocol;
cfg->nh_flags = nhm->nh_flags;
if (tb[NHA_ID])
cfg->nh_id = nla_get_u32(tb[NHA_ID]);
if (tb[NHA_FDB]) {
if (tb[NHA_OIF] || tb[NHA_BLACKHOLE] ||
tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "Fdb attribute can not be used with encap, oif or blackhole");
goto out;
}
if (nhm->nh_flags) {
NL_SET_ERR_MSG(extack, "Unsupported nexthop flags in ancillary header");
goto out;
}
cfg->nh_fdb = nla_get_flag(tb[NHA_FDB]);
}
if (tb[NHA_GROUP]) {
if (nhm->nh_family != AF_UNSPEC) {
NL_SET_ERR_MSG(extack, "Invalid family for group");
goto out;
}
cfg->nh_grp = tb[NHA_GROUP];
cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH;
if (tb[NHA_GROUP_TYPE])
cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]);
if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) {
NL_SET_ERR_MSG(extack, "Invalid group type");
goto out;
}
err = nh_check_attr_group(net, tb, ARRAY_SIZE(tb), extack);
/* no other attributes should be set */
goto out;
}
if (tb[NHA_BLACKHOLE]) {
if (tb[NHA_GATEWAY] || tb[NHA_OIF] ||
tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE] || tb[NHA_FDB]) {
NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway, oif, encap or fdb");
goto out;
}
cfg->nh_blackhole = 1;
err = 0;
goto out;
}
if (!cfg->nh_fdb && !tb[NHA_OIF]) {
NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole and non-fdb nexthops");
goto out;
}
if (!cfg->nh_fdb && tb[NHA_OIF]) {
cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]);
if (cfg->nh_ifindex)
cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex);
if (!cfg->dev) {
NL_SET_ERR_MSG(extack, "Invalid device index");
goto out;
} else if (!(cfg->dev->flags & IFF_UP)) {
NL_SET_ERR_MSG(extack, "Nexthop device is not up");
err = -ENETDOWN;
goto out;
} else if (!netif_carrier_ok(cfg->dev)) {
NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down");
err = -ENETDOWN;
goto out;
}
}
err = -EINVAL;
if (tb[NHA_GATEWAY]) {
struct nlattr *gwa = tb[NHA_GATEWAY];
switch (cfg->nh_family) {
case AF_INET:
if (nla_len(gwa) != sizeof(u32)) {
NL_SET_ERR_MSG(extack, "Invalid gateway");
goto out;
}
cfg->gw.ipv4 = nla_get_be32(gwa);
break;
case AF_INET6:
if (nla_len(gwa) != sizeof(struct in6_addr)) {
NL_SET_ERR_MSG(extack, "Invalid gateway");
goto out;
}
cfg->gw.ipv6 = nla_get_in6_addr(gwa);
break;
default:
NL_SET_ERR_MSG(extack,
"Unknown address family for gateway");
goto out;
}
} else {
/* device only nexthop (no gateway) */
if (cfg->nh_flags & RTNH_F_ONLINK) {
NL_SET_ERR_MSG(extack,
"ONLINK flag can not be set for nexthop without a gateway");
goto out;
}
}
if (tb[NHA_ENCAP]) {
cfg->nh_encap = tb[NHA_ENCAP];
if (!tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing");
goto out;
}
cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]);
err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack);
if (err < 0)
goto out;
} else if (tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing");
goto out;
}
err = 0;
out:
return err;
}
/* rtnl */
static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nh_config cfg;
struct nexthop *nh;
int err;
err = rtm_to_nh_config(net, skb, nlh, &cfg, extack);
if (!err) {
nh = nexthop_add(net, &cfg, extack);
if (IS_ERR(nh))
err = PTR_ERR(nh);
}
return err;
}
static int __nh_valid_get_del_req(const struct nlmsghdr *nlh,
struct nlattr **tb, u32 *id,
struct netlink_ext_ack *extack)
{
struct nhmsg *nhm = nlmsg_data(nlh);
if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
NL_SET_ERR_MSG(extack, "Invalid values in header");
return -EINVAL;
}
if (!tb[NHA_ID]) {
NL_SET_ERR_MSG(extack, "Nexthop id is missing");
return -EINVAL;
}
*id = nla_get_u32(tb[NHA_ID]);
if (!(*id)) {
NL_SET_ERR_MSG(extack, "Invalid nexthop id");
return -EINVAL;
}
return 0;
}
static int nh_valid_get_del_req(const struct nlmsghdr *nlh, u32 *id,
struct netlink_ext_ack *extack)
{
struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get)];
int err;
err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
ARRAY_SIZE(rtm_nh_policy_get) - 1,
rtm_nh_policy_get, extack);
if (err < 0)
return err;
return __nh_valid_get_del_req(nlh, tb, id, extack);
}
/* rtnl */
static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nl_info nlinfo = {
.nlh = nlh,
.nl_net = net,
.portid = NETLINK_CB(skb).portid,
};
struct nexthop *nh;
int err;
u32 id;
err = nh_valid_get_del_req(nlh, &id, extack);
if (err)
return err;
nh = nexthop_find_by_id(net, id);
if (!nh)
return -ENOENT;
remove_nexthop(net, nh, &nlinfo);
return 0;
}
/* rtnl */
static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(in_skb->sk);
struct sk_buff *skb = NULL;
struct nexthop *nh;
int err;
u32 id;
err = nh_valid_get_del_req(nlh, &id, extack);
if (err)
return err;
err = -ENOBUFS;
skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
if (!skb)
goto out;
err = -ENOENT;
nh = nexthop_find_by_id(net, id);
if (!nh)
goto errout_free;
err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq, 0);
if (err < 0) {
WARN_ON(err == -EMSGSIZE);
goto errout_free;
}
err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
out:
return err;
errout_free:
kfree_skb(skb);
goto out;
}
struct nh_dump_filter {
int dev_idx;
int master_idx;
bool group_filter;
bool fdb_filter;
};
static bool nh_dump_filtered(struct nexthop *nh,
struct nh_dump_filter *filter, u8 family)
{
const struct net_device *dev;
const struct nh_info *nhi;
if (filter->group_filter && !nh->is_group)
return true;
if (!filter->dev_idx && !filter->master_idx && !family)
return false;
if (nh->is_group)
return true;
nhi = rtnl_dereference(nh->nh_info);
if (family && nhi->family != family)
return true;
dev = nhi->fib_nhc.nhc_dev;
if (filter->dev_idx && (!dev || dev->ifindex != filter->dev_idx))
return true;
if (filter->master_idx) {
struct net_device *master;
if (!dev)
return true;
master = netdev_master_upper_dev_get((struct net_device *)dev);
if (!master || master->ifindex != filter->master_idx)
return true;
}
return false;
}
static int __nh_valid_dump_req(const struct nlmsghdr *nlh, struct nlattr **tb,
struct nh_dump_filter *filter,
struct netlink_ext_ack *extack)
{
struct nhmsg *nhm;
u32 idx;
if (tb[NHA_OIF]) {
idx = nla_get_u32(tb[NHA_OIF]);
if (idx > INT_MAX) {
NL_SET_ERR_MSG(extack, "Invalid device index");
return -EINVAL;
}
filter->dev_idx = idx;
}
if (tb[NHA_MASTER]) {
idx = nla_get_u32(tb[NHA_MASTER]);
if (idx > INT_MAX) {
NL_SET_ERR_MSG(extack, "Invalid master device index");
return -EINVAL;
}
filter->master_idx = idx;
}
filter->group_filter = nla_get_flag(tb[NHA_GROUPS]);
filter->fdb_filter = nla_get_flag(tb[NHA_FDB]);
nhm = nlmsg_data(nlh);
if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request");
return -EINVAL;
}
return 0;
}
static int nh_valid_dump_req(const struct nlmsghdr *nlh,
struct nh_dump_filter *filter,
struct netlink_callback *cb)
{
struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump)];
int err;
err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
ARRAY_SIZE(rtm_nh_policy_dump) - 1,
rtm_nh_policy_dump, cb->extack);
if (err < 0)
return err;
return __nh_valid_dump_req(nlh, tb, filter, cb->extack);
}
struct rtm_dump_nh_ctx {
u32 idx;
};
static struct rtm_dump_nh_ctx *
rtm_dump_nh_ctx(struct netlink_callback *cb)
{
struct rtm_dump_nh_ctx *ctx = (void *)cb->ctx;
BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
return ctx;
}
static int rtm_dump_walk_nexthops(struct sk_buff *skb,
struct netlink_callback *cb,
struct rb_root *root,
struct rtm_dump_nh_ctx *ctx,
int (*nh_cb)(struct sk_buff *skb,
struct netlink_callback *cb,
struct nexthop *nh, void *data),
void *data)
{
struct rb_node *node;
int idx = 0, s_idx;
int err;
s_idx = ctx->idx;
for (node = rb_first(root); node; node = rb_next(node)) {
struct nexthop *nh;
if (idx < s_idx)
goto cont;
nh = rb_entry(node, struct nexthop, rb_node);
ctx->idx = idx;
err = nh_cb(skb, cb, nh, data);
if (err)
return err;
cont:
idx++;
}
ctx->idx = idx;
return 0;
}
static int rtm_dump_nexthop_cb(struct sk_buff *skb, struct netlink_callback *cb,
struct nexthop *nh, void *data)
{
struct nhmsg *nhm = nlmsg_data(cb->nlh);
struct nh_dump_filter *filter = data;
if (nh_dump_filtered(nh, filter, nhm->nh_family))
return 0;
return nh_fill_node(skb, nh, RTM_NEWNEXTHOP,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI);
}
/* rtnl */
static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
{
struct rtm_dump_nh_ctx *ctx = rtm_dump_nh_ctx(cb);
struct net *net = sock_net(skb->sk);
struct rb_root *root = &net->nexthop.rb_root;
struct nh_dump_filter filter = {};
int err;
err = nh_valid_dump_req(cb->nlh, &filter, cb);
if (err < 0)
return err;
err = rtm_dump_walk_nexthops(skb, cb, root, ctx,
&rtm_dump_nexthop_cb, &filter);
if (err < 0) {
if (likely(skb->len))
goto out;
goto out_err;
}
out:
err = skb->len;
out_err:
cb->seq = net->nexthop.seq;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
return err;
}
static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu)
{
unsigned int hash = nh_dev_hashfn(dev->ifindex);
struct net *net = dev_net(dev);
struct hlist_head *head = &net->nexthop.devhash[hash];
struct hlist_node *n;
struct nh_info *nhi;
hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
if (nhi->fib_nhc.nhc_dev == dev) {
if (nhi->family == AF_INET)
fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu,
orig_mtu);
}
}
}
/* rtnl */
static int nh_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct netdev_notifier_info_ext *info_ext;
switch (event) {
case NETDEV_DOWN:
case NETDEV_UNREGISTER:
nexthop_flush_dev(dev, event);
break;
case NETDEV_CHANGE:
if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP)))
nexthop_flush_dev(dev, event);
break;
case NETDEV_CHANGEMTU:
info_ext = ptr;
nexthop_sync_mtu(dev, info_ext->ext.mtu);
rt_cache_flush(dev_net(dev));
break;
}
return NOTIFY_DONE;
}
static struct notifier_block nh_netdev_notifier = {
.notifier_call = nh_netdev_event,
};
static int nexthops_dump(struct net *net, struct notifier_block *nb,
struct netlink_ext_ack *extack)
{
struct rb_root *root = &net->nexthop.rb_root;
struct rb_node *node;
int err = 0;
for (node = rb_first(root); node; node = rb_next(node)) {
struct nexthop *nh;
nh = rb_entry(node, struct nexthop, rb_node);
err = call_nexthop_notifier(nb, net, NEXTHOP_EVENT_REPLACE, nh,
extack);
if (err)
break;
}
return err;
}
int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
struct netlink_ext_ack *extack)
{
int err;
rtnl_lock();
err = nexthops_dump(net, nb, extack);
if (err)
goto unlock;
err = blocking_notifier_chain_register(&net->nexthop.notifier_chain,
nb);
unlock:
rtnl_unlock();
return err;
}
EXPORT_SYMBOL(register_nexthop_notifier);
int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&net->nexthop.notifier_chain,
nb);
}
EXPORT_SYMBOL(unregister_nexthop_notifier);
void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap)
{
struct nexthop *nexthop;
rcu_read_lock();
nexthop = nexthop_find_by_id(net, id);
if (!nexthop)
goto out;
nexthop->nh_flags &= ~(RTNH_F_OFFLOAD | RTNH_F_TRAP);
if (offload)
nexthop->nh_flags |= RTNH_F_OFFLOAD;
if (trap)
nexthop->nh_flags |= RTNH_F_TRAP;
out:
rcu_read_unlock();
}
EXPORT_SYMBOL(nexthop_set_hw_flags);
static void __net_exit nexthop_net_exit(struct net *net)
{
rtnl_lock();
flush_all_nexthops(net);
rtnl_unlock();
kfree(net->nexthop.devhash);
}
static int __net_init nexthop_net_init(struct net *net)
{
size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE;
net->nexthop.rb_root = RB_ROOT;
net->nexthop.devhash = kzalloc(sz, GFP_KERNEL);
if (!net->nexthop.devhash)
return -ENOMEM;
BLOCKING_INIT_NOTIFIER_HEAD(&net->nexthop.notifier_chain);
return 0;
}
static struct pernet_operations nexthop_net_ops = {
.init = nexthop_net_init,
.exit = nexthop_net_exit,
};
static int __init nexthop_init(void)
{
register_pernet_subsys(&nexthop_net_ops);
register_netdevice_notifier(&nh_netdev_notifier);
rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop,
rtm_dump_nexthop, 0);
rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
return 0;
}
subsys_initcall(nexthop_init);
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