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, 6 insertions, 3 deletions

diff --git a/icmp.c b/icmp.c
index 7cf31e6..9b95be2 100644
--- a/icmp.c
+++ b/icmp.c
@@ -162,12 +162,15 @@ static void icmp_ping_close(const struct ctx *c,
  * @id_sock:	Pointer to ping flow entry slot in icmp_id_map[] to update
  * @af:		Address family, AF_INET or AF_INET6
  * @id:		ICMP id for the new socket
+ * @saddr:	Source address
+ * @daddr:	Destination address
  *
  * Return: Newly opened ping flow, or NULL on failure
  */
 static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
 					    struct icmp_ping_flow **id_sock,
-					    sa_family_t af, uint16_t id)
+					    sa_family_t af, uint16_t id,
+					    const void *saddr, const void *daddr)
 {
 	uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6;
 	union epoll_ref ref = { .type = EPOLL_TYPE_PING };
@@ -179,7 +182,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
 	if (!flow)
 		return NULL;
 
-	flow_initiate(flow, PIF_TAP);
+	flow_initiate_af(flow, PIF_TAP, af, saddr, id, daddr, id);
 	flow_target(flow, PIF_HOST);
 	pingf = FLOW_SET_TYPE(flow, flowtype, ping);
 
@@ -285,7 +288,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	}
 
 	if (!(pingf = *id_sock))
-		if (!(pingf = icmp_ping_new(c, id_sock, af, id)))
+		if (!(pingf = icmp_ping_new(c, id_sock, af, id, saddr, daddr)))
 			return 1;
 
 	pingf->ts = now->tv_sec;