kern/64167: [patch] IPFilter IPv6 fastroute - MTU bug

[Antonio Tapiador del Dujo]

>Number:         64167
>Category:       kern
>Synopsis:       [patch] IPFilter IPv6 fastroute - MTU bug
>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:   Fri Mar 12 07:50:19 PST 2004
>Closed-Date:
>Last-Modified:
>Originator:     Antonio Tapiador del Dujo
>Release:        FreeBSD 5.2.1-RELEASE
>Organization:
DIT - UPM
>Environment:
System: FreeBSD x.dit.upm.es 5.2.1-RELEASE FreeBSD 5.2.1-RELEASE #8: Fri Mar 12 16:09:48 CET 2004     root at x.dit.upm.es:/usr/src/sys/i386/compile/MH-2  i386

IP Filter: v3.4.31

>Description:
Using ipfilter IPv6 fastroute on rl0 to gif0:<ip6_addr> (moving packets 
to IPv6 over IPv6 tunnel interface) fails.

In /usr/src/sys/contrib/ipfilter/netinet/ip_fil.c, function fastroute6,
line 2022, ND_IFINFO(ifp)->linkmtu gives 0 mtu size

>How-To-Repeat:
Creating an IPv6oIPv6 tunnel and setting ipfilter ipv6 rule like:
pass out on rl0 to gif0:<ip6_addr> from <ip6_prefix>::/80 to any

>Fix:
Remplacing ND_IFINFO(ifp)->linkmtu with IN6_LINKMTU(ifp) gives the
correct mtu value

	


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