kern/90973: [net] [patch] if_bridge does not handle arp for own addresses

Meno Abels meno.abels at
Tue Dec 27 03:00:48 PST 2005

>Number:         90973
>Category:       kern
>Synopsis:       [net] [patch] if_bridge does not handle arp for own addresses
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Dec 27 11:00:12 GMT 2005
>Originator:     Meno Abels
>Release:        FreeBSD 6.0-RELEASE i386
Adviser COM
System: FreeBSD sshd 6.0-RELEASE FreeBSD 6.0-RELEASE #1: Thu Jul 28 23:45:40 MEST 2005 root at i386

	If you have for example the following config:
	and these interfaces are bridged:
		ifconfig bridge0 addm lnc1 addm tap1 up
	If you now send packets over tap1 to the arp lookup is not answered by 
	bridged host.
	ping and arp -d
	In if_ether.c the detection of the bridge works on every bridge interfaces but
        not for the bridged(if_bridge) interface himself. This dectection is only required if
	there is a cloned bridge interface. So I added these:

--- sys/netinet/if_ether.c      7 Oct 2005 01:51:29 -0000
+++ sys/netinet/if_ether.c      27 Dec 2005 10:33:31 -0000
@@ -607,7 +607,7 @@
        int carp_match = 0;
-       if (do_bridge || ifp->if_bridge)
+       if (do_bridge || ifp->if_bridge || ifp->if_type == IFT_BRIDGE)
                bridged = 1;
        req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));


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