From d7e7747ac5c2496c98291944c6066adaa9f3b975 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 26 Aug 2021 15:54:22 +0200 Subject: netfilter: refuse insertion if chain has grown too large Also add a stat counter for this that gets exported both via old /proc interface and ctnetlink. Assuming the old default size of 16536 buckets and max hash occupancy of 64k, this results in 128k insertions (origin+reply), so ~8 entries per chain on average. The revised settings in this series will result in about two entries per bucket on average. This allows a hard-limit ceiling of 64. This is not tunable at the moment, but its possible to either increase nf_conntrack_buckets or decrease nf_conntrack_max to reduce average lengths. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nfnetlink_conntrack.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/netfilter/nfnetlink_conntrack.h b/include/uapi/linux/netfilter/nfnetlink_conntrack.h index d8484be72fdc..5ade231f497b 100644 --- a/include/uapi/linux/netfilter/nfnetlink_conntrack.h +++ b/include/uapi/linux/netfilter/nfnetlink_conntrack.h @@ -257,6 +257,7 @@ enum ctattr_stats_cpu { CTA_STATS_ERROR, CTA_STATS_SEARCH_RESTART, CTA_STATS_CLASH_RESOLVE, + CTA_STATS_CHAIN_TOOLONG, __CTA_STATS_MAX, }; #define CTA_STATS_MAX (__CTA_STATS_MAX - 1) -- cgit v1.2.3