Add a per-interface-address pointer to a function that can be supplied

by a protocol, to detirmine if an address matches the net this address
is part of.  This is needed by protocols for which netmasks
"just don't work", for example appletalk.

Also add the code in appletalk to make use of this new feature.
Thsi fixes one of the longest standing bugs in appletalk.
The inability to talk to machines to which the path is via a router
which is on a different net, but the same netrange, as your interface.
Protocols that do not supply this function (e.g. IP) should not be affected.

1 files changed, 19 insertions, 3 deletions

diff --git a/sys/netatalk/ddp_output.c b/sys/netatalk/ddp_output.c
index 34f010b..9759ccc 100644
--- a/sys/netatalk/ddp_output.c
+++ b/sys/netatalk/ddp_output.c
@@ -119,16 +119,32 @@ ddp_route( struct mbuf *m, struct route *ro)
     struct ifnet	*ifp = NULL;
     u_short		net;
 
-    if ( ro->ro_rt && ( ifp = ro->ro_rt->rt_ifp )) {
-	net = satosat( ro->ro_rt->rt_gateway )->sat_addr.s_net;
+    /*
+     * if we have a route, find the ifa that refers to this route.
+     * I.e The ifa used to get to the gateway.
+     */
+    if ( (ro->ro_rt == NULL)
+    || ( ro->ro_rt->rt_ifa == NULL )
+    || ( (ifp = ro->ro_rt->rt_ifa->ifa_ifp) == NULL )) {
+	rtalloc(ro);
+    }
+    if ( (ro->ro_rt != NULL)
+    && ( ro->ro_rt->rt_ifa )
+    && ( ifp = ro->ro_rt->rt_ifa->ifa_ifp )) {
+	net = satosat(ro->ro_rt->rt_gateway)->sat_addr.s_net;
 	for ( aa = at_ifaddr; aa; aa = aa->aa_next ) {
-	    if ( aa->aa_ifp == ifp &&
+	    if (((net == 0) || (aa->aa_ifp == ifp)) &&
 		    ntohs( net ) >= ntohs( aa->aa_firstnet ) &&
 		    ntohs( net ) <= ntohs( aa->aa_lastnet )) {
 		break;
 	    }
 	}
+    } else {
+	printf( "ddp_route: still have no valid route\n");
+	m_freem( m );
+	return( EINVAL );
     }
+
     if ( aa == NULL ) {
 printf( "ddp_route: oops\n" );
 	m_freem( m );