[NETFILTER] {ip,nf}_conntrack TCP: Accept SYN+PUSH like SYN

Some devices (e.g. Qlogic iSCSI HBA hardware like QLA4010 up to firmware
3.0.0.4) initiates TCP with SYN and PUSH flags set.

The Linux TCP/IP stack deals fine with that, but the connection tracking
code doesn't.

This patch alters TCP connection tracking to accept SYN+PUSH as a valid
flag combination.

Signed-off-by: Vlad Drukker <vlad@storewiz.com>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_conntrack_proto_tcp.c

@@ -814,6 +814,7 @@ static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG) + 1] =
 {
 	[TH_SYN]			= 1,
 	[TH_SYN|TH_ACK]			= 1,
+	[TH_SYN|TH_PUSH]		= 1,
 	[TH_SYN|TH_ACK|TH_PUSH]		= 1,
 	[TH_RST]			= 1,
 	[TH_RST|TH_ACK]			= 1,

net/netfilter/nf_conntrack_proto_tcp.c

@@ -779,6 +779,7 @@ static u8 tcp_valid_flags[(TH_FIN|TH_SYN|TH_RST|TH_PUSH|TH_ACK|TH_URG) + 1] =
 {
 	[TH_SYN]			= 1,
 	[TH_SYN|TH_ACK]			= 1,
+	[TH_SYN|TH_PUSH]		= 1,
 	[TH_SYN|TH_ACK|TH_PUSH]		= 1,
 	[TH_RST]			= 1,
 	[TH_RST|TH_ACK]			= 1,