flow: Common address information for initiating side

Handling of each protocol needs some degree of tracking of the
addresses and ports at the end of each connection or flow.  Sometimes
that's explicit (as in the guest visible addresses for TCP
connections), sometimes implicit (the bound and connected addresses of
sockets).

To allow more consistent handling across protocols we want to
uniformly track the address and port at each end of the connection.
Furthermore, because we allow port remapping, and we sometimes need to
apply NAT, the addresses and ports can be different as seen by the
guest/namespace and as by the host.

Introduce 'struct flowside' to keep track of address and port
information related to one side of a flow. Store two of these in the
common fields of a flow to track that information for both sides.

For now we only populate the initiating side, requiring that
information be completed when a flows enter INI.  Later patches will
populate the target side.

For now this leaves some information redundantly recorded in both generic
and type specific fields.  We'll fix that in later patches.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/tcp.c b/tcp.c
index c5431f1..286a417 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1666,7 +1666,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 	if (!(flow = flow_alloc()))
 		return;
 
-	flow_initiate(flow, PIF_TAP);
+	flow_initiate_af(flow, PIF_TAP, af, saddr, srcport, daddr, dstport);
 
 	flow_target(flow, PIF_HOST);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
@@ -2351,7 +2351,9 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 	if (s < 0)
 		goto cancel;
 
-	flow_initiate(flow, ref.tcp_listen.pif);
+	/* FIXME: When listening port has a specific bound address, record that
+	 * as the forwarding address */
+	flow_initiate_sa(flow, ref.tcp_listen.pif, &sa, ref.tcp_listen.port);
 
 	if (sa.sa_family == AF_INET) {
 		const struct in_addr *addr = &sa.sa4.sin_addr;