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author | Florian Westphal <fw@strlen.de> | 2016-07-05 12:07:23 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-07-11 11:47:50 +0200 |
commit | 7c9664351980aaa6a4b8837a314360b3a4ad382a (patch) | |
tree | b3c4b235e53c9576adc9eb7eec5ea9a73d406e9b /net/netfilter/nf_nat_core.c | |
parent | 242922a027176cd260c5adce4ba6bbfa3a05190c (diff) | |
download | linux-stable-7c9664351980aaa6a4b8837a314360b3a4ad382a.tar.gz linux-stable-7c9664351980aaa6a4b8837a314360b3a4ad382a.tar.bz2 linux-stable-7c9664351980aaa6a4b8837a314360b3a4ad382a.zip |
netfilter: move nat hlist_head to nf_conn
The nat extension structure is 32bytes in size on x86_64:
struct nf_conn_nat {
struct hlist_node bysource; /* 0 16 */
struct nf_conn * ct; /* 16 8 */
union nf_conntrack_nat_help help; /* 24 4 */
int masq_index; /* 28 4 */
/* size: 32, cachelines: 1, members: 4 */
/* last cacheline: 32 bytes */
};
The hlist is needed to quickly check for possible tuple collisions
when installing a new nat binding. Storing this in the extension
area has two drawbacks:
1. We need ct backpointer to get the conntrack struct from the extension.
2. When reallocation of extension area occurs we need to fixup the bysource
hash head via hlist_replace_rcu.
We can avoid both by placing the hlist_head in nf_conn and place nf_conn in
the bysource hash rather than the extenstion.
We can also remove the ->move support; no other extension needs it.
Moving the entire nat extension into nf_conn would be possible as well but
then we have to add yet another callback for deletion from the bysource
hash table rather than just using nat extension ->destroy hook for this.
nf_conn size doesn't increase due to aligment, followup patch replaces
hlist_node with single pointer.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nf_nat_core.c')
-rw-r--r-- | net/netfilter/nf_nat_core.c | 33 |
1 files changed, 7 insertions, 26 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 6877a396f8fc..692534701426 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -198,11 +198,9 @@ find_appropriate_src(struct net *net, const struct nf_nat_range *range) { unsigned int h = hash_by_src(net, tuple); - const struct nf_conn_nat *nat; const struct nf_conn *ct; - hlist_for_each_entry_rcu(nat, &nf_nat_bysource[h], bysource) { - ct = nat->ct; + 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)) { @@ -435,8 +433,7 @@ nf_nat_setup_info(struct nf_conn *ct, spin_lock_bh(&nf_nat_lock); /* nf_conntrack_alter_reply might re-allocate extension aera */ nat = nfct_nat(ct); - nat->ct = ct; - hlist_add_head_rcu(&nat->bysource, + hlist_add_head_rcu(&ct->nat_bysource, &nf_nat_bysource[srchash]); spin_unlock_bh(&nf_nat_lock); } @@ -543,7 +540,7 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data) if (nf_nat_proto_remove(ct, data)) return 1; - if (!nat || !nat->ct) + if (!nat) return 0; /* This netns is being destroyed, and conntrack has nat null binding. @@ -556,9 +553,8 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data) return 1; spin_lock_bh(&nf_nat_lock); - hlist_del_rcu(&nat->bysource); + hlist_del_rcu(&ct->nat_bysource); ct->status &= ~IPS_NAT_DONE_MASK; - nat->ct = NULL; spin_unlock_bh(&nf_nat_lock); add_timer(&ct->timeout); @@ -688,27 +684,13 @@ static void nf_nat_cleanup_conntrack(struct nf_conn *ct) { struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); - if (nat == NULL || nat->ct == NULL) + if (!nat) return; - NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE); - - spin_lock_bh(&nf_nat_lock); - hlist_del_rcu(&nat->bysource); - spin_unlock_bh(&nf_nat_lock); -} - -static void nf_nat_move_storage(void *new, void *old) -{ - struct nf_conn_nat *new_nat = new; - struct nf_conn_nat *old_nat = old; - struct nf_conn *ct = old_nat->ct; - - if (!ct || !(ct->status & IPS_SRC_NAT_DONE)) - return; + NF_CT_ASSERT(ct->status & IPS_SRC_NAT_DONE); spin_lock_bh(&nf_nat_lock); - hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); + hlist_del_rcu(&ct->nat_bysource); spin_unlock_bh(&nf_nat_lock); } @@ -716,7 +698,6 @@ static struct nf_ct_ext_type nat_extend __read_mostly = { .len = sizeof(struct nf_conn_nat), .align = __alignof__(struct nf_conn_nat), .destroy = nf_nat_cleanup_conntrack, - .move = nf_nat_move_storage, .id = NF_CT_EXT_NAT, .flags = NF_CT_EXT_F_PREALLOC, }; |