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netfilter: nf_conntrack_tcp: decrease timeouts while data in unacknowledged 

In order to time out dead connections quicker, keep track of outstanding data
and cap the timeout.

Suggested by Herbert Xu.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2008-07-31 00:38:01 -07:00 committed by David S. Miller
parent a97a6f1077
commit ae375044d3
2 changed files with 27 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/netfilter/nf_conntrack_tcp.h
View File

@ -30,6 +30,9 @@ enum tcp_conntrack {
/* Be liberal in window checking */
#define IP_CT_TCP_FLAG_BE_LIBERAL 0x08
/* Has unacknowledged data */
#define IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED 0x10
struct nf_ct_tcp_flags {
u_int8_t flags;
u_int8_t mask;

29
net/netfilter/nf_conntrack_proto_tcp.c
View File

@ -67,7 +67,8 @@ static const char *const tcp_conntrack_names[] = {
/* RFC1122 says the R2 limit should be at least 100 seconds.
Linux uses 15 packets as limit, which corresponds
to ~13-30min depending on RTO. */
static unsigned int nf_ct_tcp_timeout_max_retrans __read_mostly = 5 MINS;
static unsigned int nf_ct_tcp_timeout_max_retrans __read_mostly = 5 MINS;
static unsigned int nf_ct_tcp_timeout_unacknowledged __read_mostly = 5 MINS;
static unsigned int tcp_timeouts[TCP_CONNTRACK_MAX] __read_mostly = {
[TCP_CONNTRACK_SYN_SENT] = 2 MINS,
@ -625,8 +626,10 @@ static bool tcp_in_window(const struct nf_conn *ct,
swin = win + (sack - ack);
if (sender->td_maxwin < swin)
sender->td_maxwin = swin;
if (after(end, sender->td_end))
if (after(end, sender->td_end)) {
sender->td_end = end;
sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
}
/*
* Update receiver data.
*/
@ -637,6 +640,8 @@ static bool tcp_in_window(const struct nf_conn *ct,
if (win == 0)
receiver->td_maxend++;
}
if (ack == receiver->td_end)
receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED;
/*
* Check retransmissions.
@ -951,9 +956,16 @@ static int tcp_packet(struct nf_conn *ct,
if (old_state != new_state
&& new_state == TCP_CONNTRACK_FIN_WAIT)
ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
timeout = ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans
&& tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
? nf_ct_tcp_timeout_max_retrans : tcp_timeouts[new_state];
if (ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans &&
tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans)
timeout = nf_ct_tcp_timeout_max_retrans;
else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
tcp_timeouts[new_state] > nf_ct_tcp_timeout_unacknowledged)
timeout = nf_ct_tcp_timeout_unacknowledged;
else
timeout = tcp_timeouts[new_state];
write_unlock_bh(&tcp_lock);
nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
@ -1235,6 +1247,13 @@ static struct ctl_table tcp_sysctl_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_tcp_timeout_unacknowledged",
.data = &nf_ct_tcp_timeout_unacknowledged,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = &proc_dointvec_jiffies,
},
{
.ctl_name = NET_NF_CONNTRACK_TCP_LOOSE,
.procname = "nf_conntrack_tcp_loose",