From: Florian Westphal <fw@xxxxxxxxx>
make the replace function only send a ctnetlink event if the contents
of the new set is different.
Otherwise 'ct label set ct label | bar'
will cause netlink event storm since we "replace" labels for each packet.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_labels.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/net/netfilter/nf_conntrack_labels.c b/net/netfilter/nf_conntrack_labels.c
index 3a30900..bd7f26b 100644
--- a/net/netfilter/nf_conntrack_labels.c
+++ b/net/netfilter/nf_conntrack_labels.c
@@ -33,14 +33,18 @@ int nf_connlabel_set(struct nf_conn *ct, u16 bit)
}
EXPORT_SYMBOL_GPL(nf_connlabel_set);
-static void replace_u32(u32 *address, u32 mask, u32 new)
+static int replace_u32(u32 *address, u32 mask, u32 new)
{
u32 old, tmp;
do {
old = *address;
tmp = (old & mask) ^ new;
+ if (old == tmp)
+ return 0;
} while (cmpxchg(address, old, tmp) != old);
+
+ return 1;
}
int nf_connlabels_replace(struct nf_conn *ct,
@@ -49,6 +53,7 @@ int nf_connlabels_replace(struct nf_conn *ct,
{
struct nf_conn_labels *labels;
unsigned int size, i;
+ int changed = 0;
u32 *dst;
labels = nf_ct_labels_find(ct);
@@ -60,16 +65,15 @@ int nf_connlabels_replace(struct nf_conn *ct,
words32 = size / sizeof(u32);
dst = (u32 *) labels->bits;
- if (words32) {
- for (i = 0; i < words32; i++)
- replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
- }
+ for (i = 0; i < words32; i++)
+ changed |= replace_u32(&dst[i], mask ? ~mask[i] : 0, data[i]);
size /= sizeof(u32);
for (i = words32; i < size; i++) /* pad */
replace_u32(&dst[i], 0, 0);
- nf_conntrack_event_cache(IPCT_LABEL, ct);
+ if (changed)
+ nf_conntrack_event_cache(IPCT_LABEL, ct);
return 0;
}
EXPORT_SYMBOL_GPL(nf_connlabels_replace);
--
2.1.4
--
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