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From: Felix Fietkau <nbd@nbd.name>
Subject: netfilter: optional tcp window check
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
net/netfilter/nf_conntrack_proto_tcp.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -465,6 +465,9 @@ static bool tcp_in_window(struct nf_conn
s32 receiver_offset;
bool res, in_recv_win;
+ if (net->ct.sysctl_no_window_check)
+ return true;
+
/*
* Get the required data from the packet.
*/
@@ -1151,7 +1154,7 @@ int nf_conntrack_tcp_packet(struct nf_co
IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
timeout = timeouts[TCP_CONNTRACK_UNACK];
- else if (ct->proto.tcp.last_win == 0 &&
+ else if (!net->ct.sysctl_no_window_check && ct->proto.tcp.last_win == 0 &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
timeout = timeouts[TCP_CONNTRACK_RETRANS];
else
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -671,6 +671,7 @@ enum nf_ct_sysctl_index {
NF_SYSCTL_CT_LWTUNNEL,
#endif
+ NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK,
__NF_SYSCTL_CT_LAST_SYSCTL,
};
@@ -1026,6 +1027,13 @@ static struct ctl_table nf_ct_sysctl_tab
.proc_handler = nf_hooks_lwtunnel_sysctl_handler,
},
#endif
+ [NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK] = {
+ .procname = "nf_conntrack_tcp_no_window_check",
+ .data = &init_net.ct.sysctl_no_window_check,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{}
};
@@ -1153,6 +1161,7 @@ static int nf_conntrack_standalone_init_
#ifdef CONFIG_NF_CONNTRACK_EVENTS
table[NF_SYSCTL_CT_EVENTS].data = &net->ct.sysctl_events;
#endif
+ table[NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK].data = &net->ct.sysctl_no_window_check;
#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
table[NF_SYSCTL_CT_TIMESTAMP].data = &net->ct.sysctl_tstamp;
#endif
@@ -1222,6 +1231,7 @@ static int nf_conntrack_pernet_init(stru
int ret;
net->ct.sysctl_checksum = 1;
+ net->ct.sysctl_no_window_check = 1;
ret = nf_conntrack_standalone_init_sysctl(net);
if (ret < 0)
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -109,6 +109,7 @@ struct netns_ct {
u8 sysctl_auto_assign_helper;
u8 sysctl_tstamp;
u8 sysctl_checksum;
+ u8 sysctl_no_window_check;
struct ct_pcpu __percpu *pcpu_lists;
struct ip_conntrack_stat __percpu *stat;
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