misc/123992: ECMP does not remove/disable next-hop for downed GRE interface

[Barrett Lyon]

>Number:         123992
>Category:       misc
>Synopsis:       ECMP does not remove/disable next-hop for downed GRE interface
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 26 01:10:02 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Barrett Lyon
>Release:        8.0-CURRENT
>Organization:
>Environment:
FreeBSD home.blyon.com 8.0-CURRENT FreeBSD 8.0-CURRENT #3: Sun May 25 02:18:13 PDT 2008     blyon at home.blyon.com:/usr/obj/usr/src/sys/GENERIC  i386


>Description:
Using RADIX_MPATH support in the kernel provides the desired ECMP support.

I have two GRE tunnels setup with two routes defined for the same destination.  When using ifconfig to down one of the tunnels, the route/next-hop for the downed tunnel stays active.

I would assume that once the GRE tunnel is down, the network on that interface is no longer available, thus the next-hop on that network should also no longer be an active next-hop.

This appears to work with if_em.


>How-To-Repeat:
Create two GRE tunnels, create two routes for the same destination address which route over the two GRE interfaces.

Verify that ECMP is working over the two interfaces, then down/disable one GRE interface with ifconfig and traffic goes to a bit bucket.
>Fix:
none

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