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netfilter: nat: convert nat bysrc hash to rhashtable

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It did use a fixed-size bucket list plus single lock to protect add/del.

Unlike the main conntrack table we only need to add and remove keys.
Convert it to rhashtable to get table autosizing and per-bucket locking.

The maximum number of entries is -- as before -- tied to the number of
conntracks so we do not need another upperlimit.

The change does not handle rhashtable_remove_fast error, only possible
"error" is -ENOENT, and that is something that can happen legitimetely,
e.g. because nat module was inserted at a later time and no src manip
took place yet.

Tested with http-client-benchmark + httpterm with DNAT and SNAT rules
in place.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-07-05 12:07:24 +02:00 committed by Pablo Neira Ayuso
parent 7c96643519
commit 870190a9ec
3 changed files with 69 additions and 57 deletions
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3
include/net/netfilter/nf_conntrack.h
View file

@ -17,6 +17,7 @@
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/atomic.h>
#include <linux/rhashtable.h>
#include <linux/netfilter/nf_conntrack_tcp.h>
#include <linux/netfilter/nf_conntrack_dccp.h>
@ -118,7 +119,7 @@ struct nf_conn {
struct nf_ct_ext *ext;
#if IS_ENABLED(CONFIG_NF_NAT)
struct hlist_node nat_bysource;
struct rhash_head nat_bysource;
#endif
/* Storage reserved for other modules, must be the last member */
union nf_conntrack_proto proto;

1
include/net/netfilter/nf_nat.h
View file

@ -1,5 +1,6 @@
#ifndef _NF_NAT_H
#define _NF_NAT_H
#include <linux/rhashtable.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/nf_nat.h>
#include <net/netfilter/nf_conntrack_tuple.h>

122
net/netfilter/nf_nat_core.c
View file

@ -30,17 +30,19 @@
#include <net/netfilter/nf_conntrack_zones.h>
#include <linux/netfilter/nf_nat.h>
static DEFINE_SPINLOCK(nf_nat_lock);
static DEFINE_MUTEX(nf_nat_proto_mutex);
static const struct nf_nat_l3proto __rcu *nf_nat_l3protos[NFPROTO_NUMPROTO]
__read_mostly;
static const struct nf_nat_l4proto __rcu **nf_nat_l4protos[NFPROTO_NUMPROTO]
__read_mostly;
static struct hlist_head *nf_nat_bysource __read_mostly;
static unsigned int nf_nat_htable_size __read_mostly;
static unsigned int nf_nat_hash_rnd __read_mostly;
struct nf_nat_conn_key {
const struct net *net;
const struct nf_conntrack_tuple *tuple;
const struct nf_conntrack_zone *zone;
};
static struct rhashtable nf_nat_bysource_table;
inline const struct nf_nat_l3proto *
__nf_nat_l3proto_find(u8 family)
@ -119,19 +121,17 @@ int nf_xfrm_me_harder(struct net *net, struct sk_buff *skb, unsigned int family)
EXPORT_SYMBOL(nf_xfrm_me_harder);
#endif /* CONFIG_XFRM */
/* We keep an extra hash for each conntrack, for fast searching. */
static inline unsigned int
hash_by_src(const struct net *n, const struct nf_conntrack_tuple *tuple)
static u32 nf_nat_bysource_hash(const void *data, u32 len, u32 seed)
{
unsigned int hash;
get_random_once(&nf_nat_hash_rnd, sizeof(nf_nat_hash_rnd));
const struct nf_conntrack_tuple *t;
const struct nf_conn *ct = data;
t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
/* Original src, to ensure we map it consistently if poss. */
hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32),
tuple->dst.protonum ^ nf_nat_hash_rnd ^ net_hash_mix(n));
return reciprocal_scale(hash, nf_nat_htable_size);
seed ^= net_hash_mix(nf_ct_net(ct));
return jhash2((const u32 *)&t->src, sizeof(t->src) / sizeof(u32),
t->dst.protonum ^ seed);
}
/* Is this tuple already taken? (not by us) */
@ -187,6 +187,26 @@ same_src(const struct nf_conn *ct,
t->src.u.all == tuple->src.u.all);
}
static int nf_nat_bysource_cmp(struct rhashtable_compare_arg *arg,
const void *obj)
{
const struct nf_nat_conn_key *key = arg->key;
const struct nf_conn *ct = obj;
return same_src(ct, key->tuple) &&
net_eq(nf_ct_net(ct), key->net) &&
nf_ct_zone_equal(ct, key->zone, IP_CT_DIR_ORIGINAL);
}
static struct rhashtable_params nf_nat_bysource_params = {
.head_offset = offsetof(struct nf_conn, nat_bysource),
.obj_hashfn = nf_nat_bysource_hash,
.obj_cmpfn = nf_nat_bysource_cmp,
.nelem_hint = 256,
.min_size = 1024,
.nulls_base = (1U << RHT_BASE_SHIFT),
};
/* Only called for SRC manip */
static int
find_appropriate_src(struct net *net,
@ -197,23 +217,23 @@ find_appropriate_src(struct net *net,
struct nf_conntrack_tuple *result,
const struct nf_nat_range *range)
{
unsigned int h = hash_by_src(net, tuple);
const struct nf_conn *ct;
struct nf_nat_conn_key key = {
.net = net,
.tuple = tuple,
.zone = zone
};
hlist_for_each_entry_rcu(ct, &nf_nat_bysource[h], nat_bysource) {
if (same_src(ct, tuple) &&
net_eq(net, nf_ct_net(ct)) &&
nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) {
/* Copy source part from reply tuple. */
nf_ct_invert_tuplepr(result,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
result->dst = tuple->dst;
ct = rhashtable_lookup_fast(&nf_nat_bysource_table, &key,
nf_nat_bysource_params);
if (!ct)
return 0;
if (in_range(l3proto, l4proto, result, range))
return 1;
}
}
return 0;
nf_ct_invert_tuplepr(result,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
result->dst = tuple->dst;
return in_range(l3proto, l4proto, result, range);
}
/* For [FUTURE] fragmentation handling, we want the least-used
@ -385,7 +405,6 @@ nf_nat_setup_info(struct nf_conn *ct,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype)
{
struct net *net = nf_ct_net(ct);
struct nf_conntrack_tuple curr_tuple, new_tuple;
struct nf_conn_nat *nat;
@ -426,16 +445,13 @@ nf_nat_setup_info(struct nf_conn *ct,
}
if (maniptype == NF_NAT_MANIP_SRC) {
unsigned int srchash;
int err;
srchash = hash_by_src(net,
&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
spin_lock_bh(&nf_nat_lock);
/* nf_conntrack_alter_reply might re-allocate extension aera */
nat = nfct_nat(ct);
hlist_add_head_rcu(&ct->nat_bysource,
&nf_nat_bysource[srchash]);
spin_unlock_bh(&nf_nat_lock);
err = rhashtable_insert_fast(&nf_nat_bysource_table,
&ct->nat_bysource,
nf_nat_bysource_params);
if (err)
return NF_DROP;
}
/* It's done. */
@ -552,10 +568,10 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
if (!del_timer(&ct->timeout))
return 1;
spin_lock_bh(&nf_nat_lock);
hlist_del_rcu(&ct->nat_bysource);
ct->status &= ~IPS_NAT_DONE_MASK;
spin_unlock_bh(&nf_nat_lock);
rhashtable_remove_fast(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
add_timer(&ct->timeout);
@ -687,11 +703,8 @@ static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
if (!nat)
return;
NF_CT_ASSERT(ct->status & IPS_SRC_NAT_DONE);
spin_lock_bh(&nf_nat_lock);
hlist_del_rcu(&ct->nat_bysource);
spin_unlock_bh(&nf_nat_lock);
rhashtable_remove_fast(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
}
static struct nf_ct_ext_type nat_extend __read_mostly = {
@ -826,16 +839,13 @@ static int __init nf_nat_init(void)
{
int ret;
/* Leave them the same for the moment. */
nf_nat_htable_size = nf_conntrack_htable_size;
nf_nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
if (!nf_nat_bysource)
return -ENOMEM;
ret = rhashtable_init(&nf_nat_bysource_table, &nf_nat_bysource_params);
if (ret)
return ret;
ret = nf_ct_extend_register(&nat_extend);
if (ret < 0) {
nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
rhashtable_destroy(&nf_nat_bysource_table);
printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
return ret;
}
@ -859,7 +869,7 @@ static int __init nf_nat_init(void)
return 0;
cleanup_extend:
nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
rhashtable_destroy(&nf_nat_bysource_table);
nf_ct_extend_unregister(&nat_extend);
return ret;
}
@ -877,8 +887,8 @@ static void __exit nf_nat_cleanup(void)
#endif
for (i = 0; i < NFPROTO_NUMPROTO; i++)
kfree(nf_nat_l4protos[i]);
synchronize_net();
nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
rhashtable_destroy(&nf_nat_bysource_table);
}
MODULE_LICENSE("GPL");