diff options
| author | Florian Westphal <fw@strlen.de> | 2018-12-06 11:50:49 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-12-21 00:48:38 +0100 |
| commit | d535c8a69c1924e70186d80be0a9cecaf475f166 (patch) | |
| tree | 8934ce1d48533bcf4f40c3381bd3630d6189e9f0 /net/netfilter | |
| parent | 06aa151ad1fc74a49b45336672515774a678d78d (diff) | |
netfilter: conntrack: udp: only extend timeout to stream mode after 2s
Currently DNS resolvers that send both A and AAAA queries from same source port
can trigger stream mode prematurely, which results in non-early-evictable conntrack entry
for three minutes, even though DNS requests are done in a few milliseconds.
Add a two second grace period where we continue to use the ordinary
30-second default timeout. Its enough for DNS request/response traffic,
even if two request/reply packets are involved.
ASSURED is still set, else conntrack (and thus a possible
NAT mapping ...) gets zapped too in case conntrack table runs full.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_udp.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c index c879d8d78cfd..9f2e05adba69 100644 --- a/net/netfilter/nf_conntrack_proto_udp.c +++ b/net/netfilter/nf_conntrack_proto_udp.c @@ -100,11 +100,21 @@ static int udp_packet(struct nf_conn *ct, if (!timeouts) timeouts = udp_get_timeouts(nf_ct_net(ct)); + if (!nf_ct_is_confirmed(ct)) + ct->proto.udp.stream_ts = 2 * HZ + jiffies; + /* If we've seen traffic both ways, this is some kind of UDP - stream. Extend timeout. */ + * stream. Set Assured. + */ if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { - nf_ct_refresh_acct(ct, ctinfo, skb, - timeouts[UDP_CT_REPLIED]); + unsigned long extra = timeouts[UDP_CT_UNREPLIED]; + + /* Still active after two seconds? Extend timeout. */ + if (time_after(jiffies, ct->proto.udp.stream_ts)) + extra = timeouts[UDP_CT_REPLIED]; + + nf_ct_refresh_acct(ct, ctinfo, skb, extra); + /* Also, more likely to be important, and not a probe */ if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) nf_conntrack_event_cache(IPCT_ASSURED, ct); |