bin/111493: [ PATCH ] routed doesn't use multicasts for RIPv2 via P2P interfaces

[Dan Lukes]

>Number:         111493
>Category:       bin
>Synopsis:       [ PATCH ] routed doesn't use multicasts for RIPv2 via P2P interfaces
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Apr 11 23:10:00 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     Dan Lukes
>Release:        FreeBSD 6.2-STABLE i386
>Organization:
Obludarium
>Environment:
System: FreeBSD 6.2-STABLE
src/sbin/routed/output.c,v 1.12 2005/05/31 20:28:48


>Description:
	RIPv2 should use multicasts when possible. Current code test IFF_MULTICAST
on IFF_BROADCAST interfaces only. It doesn't use multicast on non-broadcast interfaces 
even they are multicast capable.

>How-To-Repeat:
	Configure RIPv2 on a multicast capable point to point link (GRE or so), use
tcpdump to see packets
>Fix:

	Honor the IFF_MULTICAST on IFF_POINTOPOINT interfaces also. 

	P2P logic follow the ethernet logic - multicasts are not used when:
1. P2P interface is not multicast capable
2. RIPv1 compatibility requested
3. disabled by configuration (no_rip_mcast configuration directive - note, 
    it's not new directive created by patch, it exist already)


--- patch-sbin-routed-output.c begins here ---
--- sbin/routed/output.c.ORIG	Tue May 31 22:28:48 2005
+++ sbin/routed/output.c	Wed Apr 11 22:26:59 2007
@@ -140,7 +140,7 @@
 		flags = MSG_DONTROUTE;
 		break;
 	case OUT_MULTICAST:
-		if (ifp->int_if_flags & IFF_POINTOPOINT) {
+		if (ifp->int_if_flags & IFF_POINTOPOINT && ! ifp->int_if_flags & IFF_MULTICAST) {
 			msg = "Send pt-to-pt";
 		} else if (ifp->int_state & IS_DUP) {
 			trace_act("abort multicast output via %s"
@@ -874,7 +874,13 @@
 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
 			/* point-to-point hardware interface */
 			dst.sin_addr.s_addr = ifp->int_dstaddr;
-			type = OUT_UNICAST;
+
+			if (vers == RIPv2
+			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
+				type = OUT_MULTICAST;
+			} else {
+				type = OUT_UNICAST;
+			}
 
 		} else if (ifp->int_state & IS_REMOTE) {
 			/* remote interface */
@@ -963,7 +969,17 @@
 		} else if (ifp->int_if_flags & IFF_POINTOPOINT) {
 			/* point-to-point hardware interface */
 			dst.sin_addr.s_addr = ifp->int_dstaddr;
-			type = OUT_UNICAST;
+
+			/* Broadcast RIPv1 queries and RIPv2 queries
+			 * when the hardware cannot multicast.
+			 */
+			if (buf.rip_vers == RIPv2
+			    && (ifp->int_if_flags & IFF_MULTICAST)
+			    && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
+				type = OUT_MULTICAST;
+			} else {
+				type = OUT_UNICAST;
+			}
 
 		} else if (ifp->int_state & IS_REMOTE) {
 			/* remote interface */
--- patch-DAN-routed-output.c ends here ---


>Release-Note:
>Audit-Trail:
>Unformatted: