Re: VLAN issues

["Sepherosa Ziehau" <sepherosa@xxxxxxxxx>]

On 3/26/07, Matthew Dillon <dillon@apollo.backplane.com> wrote:
>     One thing I noticed about this patch is that there might be a logic
>     error when clearing vlan flags.
>
>     Lets say you have four vlan's, and you turn on promiscuous mode on two
>     of them.  This propogates to the parent.   But now what happens if you
>     turn off promiscuous mode on one of them?  Will it turn off promiscuous
>     mode in the parent even though there is still one vlan interface left
>     with it turned on?
>
>     Also, if someone turns on promisc mode on the parent, and then turns it
>     on for a vlan interface, then turns it off for a vlan interface, will
>     it turn off the mode on the parent?  We wouldn't want it to.
>
>     Another example... bridging turns on promiscuous mode.  But if an
>     interface is bridged, and someone tcpdump's a vlan under that interface,
>     then stops the tcpdump, will that turn off the interface's promiscuous
>     mode?  Again we wouldn't want it to.

IFF_PROMISC is reference counted by ifnet.if_pcount, so the problems
you described do not exist :)

Best Regards,
sephe

--
Live Free or Die