From 44bd4de9c2270b22c3c898310102bc6be9ed2978 Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Fri, 11 Feb 2011 18:00:07 +0100 Subject: [PATCH] netfilter: xt_connlimit: connlimit-above early loop termination The patch below introduces an early termination of the loop that is counting matches. It terminates once the counter has exceeded the threshold provided by the user. There's no point in continuing the loop afterwards and looking at other entries. It plays together with the following code further below: return (connections > info->limit) ^ info->inverse; where connections is the result of the counted connection, which in turn is the matches variable in the loop. So once -> matches = info->limit + 1 alias -> matches > info->limit alias -> matches > threshold we can terminate the loop. Signed-off-by: Stefan Berger Signed-off-by: Patrick McHardy --- net/netfilter/xt_connlimit.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c index e029c480740..82ce7c5fbbc 100644 --- a/net/netfilter/xt_connlimit.c +++ b/net/netfilter/xt_connlimit.c @@ -97,7 +97,8 @@ static int count_them(struct net *net, const struct nf_conntrack_tuple *tuple, const union nf_inet_addr *addr, const union nf_inet_addr *mask, - u_int8_t family) + u_int8_t family, + unsigned int threshold) { const struct nf_conntrack_tuple_hash *found; struct xt_connlimit_conn *conn; @@ -151,9 +152,14 @@ static int count_them(struct net *net, continue; } - if (same_source_net(addr, mask, &conn->tuple.src.u3, family)) + if (same_source_net(addr, mask, &conn->tuple.src.u3, family)) { /* same source network -> be counted! */ ++matches; + if (matches > threshold) { + nf_ct_put(found_ct); + break; + } + } nf_ct_put(found_ct); } @@ -207,7 +213,8 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) spin_lock_bh(&info->data->lock); connections = count_them(net, info->data, tuple_ptr, &addr, - &info->mask, par->family); + &info->mask, par->family, + info->limit); spin_unlock_bh(&info->data->lock); if (connections < 0) -- 2.39.5