diff options
| author |   Florian Westphal <fw@strlen.de> | 2017-04-16 22:08:53 +0200 |
|---|---|---|
| committer |   Pablo Neira Ayuso <pablo@netfilter.org> | 2017-04-19 17:55:17 +0200 |
| commit | c6dd940b1f747bee62865e348d360f602057196e (patch) | |
| tree | 1798d94ac1667544a3c00cd04641cdfec8e385de /net/netfilter/nf_conntrack_proto_tcp.c | |
| parent | netfilter: conntrack: use u8 for extension sizes again (diff) | |
| download | linux-dev-c6dd940b1f747bee62865e348d360f602057196e.tar.xz linux-dev-c6dd940b1f747bee62865e348d360f602057196e.zip | |
netfilter: allow early drop of assured conntracks
If insertion of a new conntrack fails because the table is full, the kernel
searches the next buckets of the hash slot where the new connection
was supposed to be inserted at for an entry that hasn't seen traffic
in reply direction (non-assured), if it finds one, that entry is
is dropped and the new connection entry is allocated.
Allow the conntrack gc worker to also remove *assured* conntracks if
resources are low.
Do this by querying the l4 tracker, e.g. tcp connections are now dropped
if they are no longer established (e.g. in finwait).
This could be refined further, e.g. by adding 'soft' established timeout
(i.e., a timeout that is only used once we get close to resource
exhaustion).
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to '')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index b122e9dacfed..d0c0a31dfe74 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -1172,6 +1172,22 @@ static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, return true; } +static bool tcp_can_early_drop(const struct nf_conn *ct) +{ + switch (ct->proto.tcp.state) { + case TCP_CONNTRACK_FIN_WAIT: + case TCP_CONNTRACK_LAST_ACK: + case TCP_CONNTRACK_TIME_WAIT: + case TCP_CONNTRACK_CLOSE: + case TCP_CONNTRACK_CLOSE_WAIT: + return true; + default: + break; + } + + return false; +} + #if IS_ENABLED(CONFIG_NF_CT_NETLINK) #include <linux/netfilter/nfnetlink.h> @@ -1549,6 +1565,7 @@ struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly = .get_timeouts = tcp_get_timeouts, .new = tcp_new, .error = tcp_error, + .can_early_drop = tcp_can_early_drop, #if IS_ENABLED(CONFIG_NF_CT_NETLINK) .to_nlattr = tcp_to_nlattr, .nlattr_size = tcp_nlattr_size, @@ -1586,6 +1603,7 @@ struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly = .get_timeouts = tcp_get_timeouts, .new = tcp_new, .error = tcp_error, + .can_early_drop = tcp_can_early_drop, #if IS_ENABLED(CONFIG_NF_CT_NETLINK) .to_nlattr = tcp_to_nlattr, .nlattr_size = tcp_nlattr_size, |