Re: IFF_PROMISC bug?

[Andi Kleen <ak@xxxxxxx>]

On Tue, Feb 12, 2002 at 08:58:09PM -0800, David S. Miller wrote:
>    From: Jeff Garzik <jgarzik@xxxxxxxxxxxxxxxx>
>    Date: Tue, 12 Feb 2002 23:54:54 -0500
>    
>    Since netlink flags and dmesg show promisc mode, and promisc mode works,
>    and SIOCGIFLAGS used to return IFF_PROMISC, I made the assumption that
>    the problem was elsewhere :)
> 
> Can you trace the value of dev->gflags for me through all of these
> actions?  It should contain IFF_PROMISC when set by this bit of code:

David, it is not a bug, but more a FAQ. 

Newer libpcap uses the PACKET_ADD_MEMBERSHIP to PACKET_MR_PROMISC socket 
options. They have an reference count instead of
the old broken non ref counted bit.  packet calls dev_set_promiscuity directly.

Turning on/off the flag virtually when the reference count is >0 would
break compatibility so it is not done. 


-Andi