[PATCH 5/5] netfilter: SYNPROXY: fix sending window update to client

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Phil Sutter <phil@xxxxxx>

Upon receipt of SYNACK from the server, ipt_SYNPROXY first sends back an ACK to
finish the server handshake, then calls nf_ct_seqadj_init() to initiate
sequence number adjustment of forwarded packets to the client and finally sends
a window update to the client to unblock it's TX queue.

Since synproxy_send_client_ack() does not set synproxy_send_tcp()'s nfct
parameter, no sequence number adjustment happens and the client receives the
window update with incorrect sequence number. Depending on client TCP
implementation, this leads to a significant delay (until a window probe is
being sent).

Signed-off-by: Phil Sutter <phil@xxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 net/ipv4/netfilter/ipt_SYNPROXY.c  |    3 ++-
 net/ipv6/netfilter/ip6t_SYNPROXY.c |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index fe8cc18..95ea633e 100644
--- a/net/ipv4/netfilter/ipt_SYNPROXY.c
+++ b/net/ipv4/netfilter/ipt_SYNPROXY.c
@@ -226,7 +226,8 @@ synproxy_send_client_ack(const struct synproxy_net *snet,
 
 	synproxy_build_options(nth, opts);
 
-	synproxy_send_tcp(skb, nskb, NULL, 0, niph, nth, tcp_hdr_size);
+	synproxy_send_tcp(skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
+	                  niph, nth, tcp_hdr_size);
 }
 
 static bool
diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c
index bcebc24..ebbb754 100644
--- a/net/ipv6/netfilter/ip6t_SYNPROXY.c
+++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c
@@ -243,7 +243,8 @@ synproxy_send_client_ack(const struct synproxy_net *snet,
 
 	synproxy_build_options(nth, opts);
 
-	synproxy_send_tcp(snet, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size);
+	synproxy_send_tcp(snet, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY,
+	                  niph, nth, tcp_hdr_size);
 }
 
 static bool
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Netfitler Users]     [LARTC]     [Bugtraq]     [Yosemite Forum]

  Powered by Linux