+++ /dev/null
-From e1bf1687740ce1a3598a1c5e452b852ff2190682 Mon Sep 17 00:00:00 2001
-From: Florian Westphal <fw@strlen.de>
-Date: Wed, 6 Sep 2017 14:39:51 +0200
-Subject: netfilter: nat: Revert "netfilter: nat: convert nat bysrc hash to rhashtable"
-
-From: Florian Westphal <fw@strlen.de>
-
-commit e1bf1687740ce1a3598a1c5e452b852ff2190682 upstream.
-
-This reverts commit 870190a9ec9075205c0fa795a09fa931694a3ff1.
-
-It was not a good idea. The custom hash table was a much better
-fit for this purpose.
-
-A fast lookup is not essential, in fact for most cases there is no lookup
-at all because original tuple is not taken and can be used as-is.
-What needs to be fast is insertion and deletion.
-
-rhlist removal however requires a rhlist walk.
-We can have thousands of entries in such a list if source port/addresses
-are reused for multiple flows, if this happens removal requests are so
-expensive that deletions of a few thousand flows can take several
-seconds(!).
-
-The advantages that we got from rhashtable are:
-1) table auto-sizing
-2) multiple locks
-
-1) would be nice to have, but it is not essential as we have at
-most one lookup per new flow, so even a million flows in the bysource
-table are not a problem compared to current deletion cost.
-2) is easy to add to custom hash table.
-
-I tried to add hlist_node to rhlist to speed up rhltable_remove but this
-isn't doable without changing semantics. rhltable_remove_fast will
-check that the to-be-deleted object is part of the table and that
-requires a list walk that we want to avoid.
-
-Furthermore, using hlist_node increases size of struct rhlist_head, which
-in turn increases nf_conn size.
-
-Link: https://bugzilla.kernel.org/show_bug.cgi?id=196821
-Reported-by: Ivan Babrou <ibobrik@gmail.com>
-Signed-off-by: Florian Westphal <fw@strlen.de>
-Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
-
----
- include/net/netfilter/nf_conntrack.h | 3
- include/net/netfilter/nf_nat.h | 1
- net/netfilter/nf_nat_core.c | 131 ++++++++++++++---------------------
- 3 files changed, 56 insertions(+), 79 deletions(-)
-
---- a/include/net/netfilter/nf_conntrack.h
-+++ b/include/net/netfilter/nf_conntrack.h
-@@ -17,7 +17,6 @@
- #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>
-@@ -101,7 +100,7 @@ struct nf_conn {
- possible_net_t ct_net;
-
- #if IS_ENABLED(CONFIG_NF_NAT)
-- struct rhlist_head nat_bysource;
-+ struct hlist_node nat_bysource;
- #endif
- /* all members below initialized via memset */
- u8 __nfct_init_offset[0];
---- a/include/net/netfilter/nf_nat.h
-+++ b/include/net/netfilter/nf_nat.h
-@@ -1,6 +1,5 @@
- #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>
---- a/net/netfilter/nf_nat_core.c
-+++ b/net/netfilter/nf_nat_core.c
-@@ -30,19 +30,17 @@
- #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;
-
--struct nf_nat_conn_key {
-- const struct net *net;
-- const struct nf_conntrack_tuple *tuple;
-- const struct nf_conntrack_zone *zone;
--};
--
--static struct rhltable nf_nat_bysource_table;
-+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;
-
- inline const struct nf_nat_l3proto *
- __nf_nat_l3proto_find(u8 family)
-@@ -121,17 +119,19 @@ int nf_xfrm_me_harder(struct net *net, s
- EXPORT_SYMBOL(nf_xfrm_me_harder);
- #endif /* CONFIG_XFRM */
-
--static u32 nf_nat_bysource_hash(const void *data, u32 len, u32 seed)
-+/* 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)
- {
-- const struct nf_conntrack_tuple *t;
-- const struct nf_conn *ct = data;
-+ unsigned int hash;
-+
-+ get_random_once(&nf_nat_hash_rnd, sizeof(nf_nat_hash_rnd));
-
-- 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));
-
-- seed ^= net_hash_mix(nf_ct_net(ct));
-- return jhash2((const u32 *)&t->src, sizeof(t->src) / sizeof(u32),
-- t->dst.protonum ^ seed);
-+ return reciprocal_scale(hash, nf_nat_htable_size);
- }
-
- /* Is this tuple already taken? (not by us) */
-@@ -187,28 +187,6 @@ 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;
--
-- if (!same_src(ct, key->tuple) ||
-- !net_eq(nf_ct_net(ct), key->net) ||
-- !nf_ct_zone_equal(ct, key->zone, IP_CT_DIR_ORIGINAL))
-- return 1;
--
-- return 0;
--}
--
--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,
--};
--
- /* Only called for SRC manip */
- static int
- find_appropriate_src(struct net *net,
-@@ -219,26 +197,22 @@ 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
-- };
-- struct rhlist_head *hl, *h;
--
-- hl = rhltable_lookup(&nf_nat_bysource_table, &key,
-- nf_nat_bysource_params);
-
-- rhl_for_each_entry_rcu(ct, h, hl, nat_bysource) {
-- nf_ct_invert_tuplepr(result,
-- &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
-- result->dst = tuple->dst;
-+ 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;
-
-- if (in_range(l3proto, l4proto, result, range))
-- return 1;
-+ if (in_range(l3proto, l4proto, result, range))
-+ return 1;
-+ }
- }
--
- return 0;
- }
-
-@@ -411,6 +385,7 @@ 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;
-
-@@ -452,19 +427,16 @@ nf_nat_setup_info(struct nf_conn *ct,
- }
-
- if (maniptype == NF_NAT_MANIP_SRC) {
-- struct nf_nat_conn_key key = {
-- .net = nf_ct_net(ct),
-- .tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
-- .zone = nf_ct_zone(ct),
-- };
-- int err;
--
-- err = rhltable_insert_key(&nf_nat_bysource_table,
-- &key,
-- &ct->nat_bysource,
-- nf_nat_bysource_params);
-- if (err)
-- return NF_DROP;
-+ unsigned int srchash;
-+
-+ 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);
- }
-
- /* It's done. */
-@@ -578,9 +550,10 @@ static int nf_nat_proto_clean(struct nf_
- * Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
- * will delete entry from already-freed table.
- */
-+ spin_lock_bh(&nf_nat_lock);
-+ hlist_del_rcu(&ct->nat_bysource);
- ct->status &= ~IPS_NAT_DONE_MASK;
-- rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
-- nf_nat_bysource_params);
-+ spin_unlock_bh(&nf_nat_lock);
-
- /* don't delete conntrack. Although that would make things a lot
- * simpler, we'd end up flushing all conntracks on nat rmmod.
-@@ -710,8 +683,11 @@ static void nf_nat_cleanup_conntrack(str
- if (!nat)
- return;
-
-- rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
-- nf_nat_bysource_params);
-+ 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);
- }
-
- static struct nf_ct_ext_type nat_extend __read_mostly = {
-@@ -846,13 +822,16 @@ static int __init nf_nat_init(void)
- {
- int ret;
-
-- ret = rhltable_init(&nf_nat_bysource_table, &nf_nat_bysource_params);
-- if (ret)
-- return 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 = nf_ct_extend_register(&nat_extend);
- if (ret < 0) {
-- rhltable_destroy(&nf_nat_bysource_table);
-+ nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
- printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
- return ret;
- }
-@@ -876,7 +855,7 @@ static int __init nf_nat_init(void)
- return 0;
-
- cleanup_extend:
-- rhltable_destroy(&nf_nat_bysource_table);
-+ nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
- nf_ct_extend_unregister(&nat_extend);
- return ret;
- }
-@@ -896,8 +875,8 @@ static void __exit nf_nat_cleanup(void)
-
- for (i = 0; i < NFPROTO_NUMPROTO; i++)
- kfree(nf_nat_l4protos[i]);
--
-- rhltable_destroy(&nf_nat_bysource_table);
-+ synchronize_net();
-+ nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size);
- }
-
- MODULE_LICENSE("GPL");
projects / thirdparty / kernel / stable-queue.git / commitdiff
