slirp: Factorizing address translation

This patch factorizes some duplicate code into a new function,
sotranslate_out(). This function perform the address translation when a
packet is transmitted to the host network. If the packet is destinated
to the host, the loopback address is used, and if the packet is
destinated to the virtual DNS, the real DNS address is used. This code
is just a copy of the existent, but factorized and ready to manage the
IPv6 case.

On the same model, the major part of udp_output() code is moved into a
new sotranslate_in(). This function is directly used in sorecvfrom(),
like sotranslate_out() in sosendto().
udp_output() becoming useless, it is removed and udp_output2() is
renamed into udp_output(). This adds consistency with the udp6_output()
function introduced by further patches.

Lastly, this factorizes some duplicate code into sotranslate_accept(), which
performs the address translation when a connection is established on the host
for port forwarding: if it comes from localhost, the host virtual address is
used instead.

This prepares for IPv6 support.

Signed-off-by: Guillaume Subiron <maethor@subiron.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 3 insertions, 34 deletions

diff --git a/slirp/udp.c b/slirp/udp.c
index 7a5c95b..8203eb1 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -236,7 +236,7 @@ bad:
 	m_free(m);
 }
 
-int udp_output2(struct socket *so, struct mbuf *m,
+int udp_output(struct socket *so, struct mbuf *m,
                 struct sockaddr_in *saddr, struct sockaddr_in *daddr,
                 int iptos)
 {
@@ -287,31 +287,6 @@ int udp_output2(struct socket *so, struct mbuf *m,
 	return (error);
 }
 
-int udp_output(struct socket *so, struct mbuf *m,
-               struct sockaddr_in *addr)
-
-{
-    Slirp *slirp = so->slirp;
-    struct sockaddr_in saddr, daddr;
-
-    saddr = *addr;
-    if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
-        slirp->vnetwork_addr.s_addr) {
-        uint32_t inv_mask = ~slirp->vnetwork_mask.s_addr;
-
-        if ((so->so_faddr.s_addr & inv_mask) == inv_mask) {
-            saddr.sin_addr = slirp->vhost_addr;
-        } else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||
-                   so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
-            saddr.sin_addr = so->so_faddr;
-        }
-    }
-    daddr.sin_addr = so->so_laddr;
-    daddr.sin_port = so->so_lport;
-
-    return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
-}
-
 int
 udp_attach(struct socket *so)
 {
@@ -378,14 +353,8 @@ udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 	socket_set_fast_reuse(so->s);
 
 	getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
-	so->so_ffamily = AF_INET;
-	so->so_fport = addr.sin_port;
-	if (addr.sin_addr.s_addr == 0 ||
-	    addr.sin_addr.s_addr == loopback_addr.s_addr) {
-	   so->so_faddr = slirp->vhost_addr;
-	} else {
-	   so->so_faddr = addr.sin_addr;
-	}
+	so->fhost.sin = addr;
+	sotranslate_accept(so);
 	so->so_lfamily = AF_INET;
 	so->so_lport = lport;
 	so->so_laddr.s_addr = laddr;