Subject: Re: sys/net/if_arcsubr.c:arc_ifattach: if_mtu initialization
To: None <firstname.lastname@example.org>
From: None <email@example.com>
Date: 06/03/2002 10:09:45
>> ifp->if_mtu is not initialized in arc_ifattach(). is it intentional?
> openbsd has the following line in arc_ifattach().
>> ifp->if_mtu = (ifp->if_flags & IFF_LINK0 ? arc_phdsmtu : ARCMTU);
With the IFF_LINK0 flag cleared, IP and ARP encoding is done according to
the deprecated, but popular among Amiga users, RFC 1051 encoding (that
is, with simple header, packet type 240 / 241), and the MTU is 507.
With the IFF_LINK0 flag set, IP/ARP/RARP encoding is done according to
RFC 1201 (that is, with Packet Header Definition Standard header and
packet type 212/213). The MTU is normally 1500.
When switching between the two modes, do a
ifconfig interfacename down up to switch the mtu.
i don't see code to change IFF_LINK0 on "down up" processing.