tcp: Port redirection support for TCP
Current TCP code relies on the local port of the listening socket
being the same as the destination address of the incoming
connection. Port redirection used by many transparent proxying
techniques obviously breaks this, so we have to store the original
destination port address.
This patch extends struct inet_request_sock and stores the incoming
destination port value there. It also modifies the handshake code to
use that value as the source port when sending reply packets.
Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 12c9b4f..f6cc341 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -976,6 +976,7 @@
ireq->acked = 0;
ireq->ecn_ok = 0;
ireq->rmt_port = tcp_hdr(skb)->source;
+ ireq->loc_port = tcp_hdr(skb)->dest;
}
extern void tcp_enter_memory_pressure(struct sock *sk);