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Date: Mon, 10 May 2010 22:18:51 +0200
From: kaber@...sh.net
To: davem@...emloft.net
Cc: netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH 80/84] netfilter: nf_conntrack: extend with extra stat counter
From: Jesper Dangaard Brouer <hawk@...x.dk>
I suspect an unfortunatly series of events occuring under a DDoS
attack, in function __nf_conntrack_find() nf_contrack_core.c.
Adding a stats counter to see if the search is restarted too often.
Signed-off-by: Jesper Dangaard Brouer <hawk@...x.dk>
Signed-off-by: Patrick McHardy <kaber@...sh.net>
---
include/linux/netfilter/nf_conntrack_common.h | 1 +
.../netfilter/nf_conntrack_l3proto_ipv4_compat.c | 7 ++++---
net/netfilter/nf_conntrack_core.c | 4 +++-
net/netfilter/nf_conntrack_standalone.c | 7 ++++---
4 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/include/linux/netfilter/nf_conntrack_common.h b/include/linux/netfilter/nf_conntrack_common.h
index c608677..14e6d32 100644
--- a/include/linux/netfilter/nf_conntrack_common.h
+++ b/include/linux/netfilter/nf_conntrack_common.h
@@ -113,6 +113,7 @@ struct ip_conntrack_stat {
unsigned int expect_new;
unsigned int expect_create;
unsigned int expect_delete;
+ unsigned int search_restart;
};
/* call to create an explicit dependency on nf_conntrack. */
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
index 2fb7b76..244f7cb 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
@@ -336,12 +336,12 @@ static int ct_cpu_seq_show(struct seq_file *seq, void *v)
const struct ip_conntrack_stat *st = v;
if (v == SEQ_START_TOKEN) {
- seq_printf(seq, "entries searched found new invalid ignore delete delete_list insert insert_failed drop early_drop icmp_error expect_new expect_create expect_delete\n");
+ seq_printf(seq, "entries searched found new invalid ignore delete delete_list insert insert_failed drop early_drop icmp_error expect_new expect_create expect_delete search_restart\n");
return 0;
}
seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x %08x "
- "%08x %08x %08x %08x %08x %08x %08x %08x \n",
+ "%08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
nr_conntracks,
st->searched,
st->found,
@@ -358,7 +358,8 @@ static int ct_cpu_seq_show(struct seq_file *seq, void *v)
st->expect_new,
st->expect_create,
- st->expect_delete
+ st->expect_delete,
+ st->search_restart
);
return 0;
}
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 0c9bbe9..3907efb 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -319,8 +319,10 @@ begin:
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
- if (get_nulls_value(n) != hash)
+ if (get_nulls_value(n) != hash) {
+ NF_CT_STAT_INC(net, search_restart);
goto begin;
+ }
local_bh_enable();
return NULL;
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index faa8eb3..ea4a8d3 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -252,12 +252,12 @@ static int ct_cpu_seq_show(struct seq_file *seq, void *v)
const struct ip_conntrack_stat *st = v;
if (v == SEQ_START_TOKEN) {
- seq_printf(seq, "entries searched found new invalid ignore delete delete_list insert insert_failed drop early_drop icmp_error expect_new expect_create expect_delete\n");
+ seq_printf(seq, "entries searched found new invalid ignore delete delete_list insert insert_failed drop early_drop icmp_error expect_new expect_create expect_delete search_restart\n");
return 0;
}
seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x %08x "
- "%08x %08x %08x %08x %08x %08x %08x %08x \n",
+ "%08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
nr_conntracks,
st->searched,
st->found,
@@ -274,7 +274,8 @@ static int ct_cpu_seq_show(struct seq_file *seq, void *v)
st->expect_new,
st->expect_create,
- st->expect_delete
+ st->expect_delete,
+ st->search_restart
);
return 0;
}
--
1.7.0.4
--
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