RE: Interface filtering
RE: Interface filtering
- Subject: RE: Interface filtering
- From: "Carl Smith" <email@hidden>
- Date: Tue, 12 Apr 2005 09:26:40 -0400
- Thread-topic: Interface filtering
" Since you are using an interface filter, then the packets you get from
a specific interface are either all from a wireless connection, or none
are. Perhaps I am missing the point of your question."
Well you could have a situation where the machine is both wired, DSL
cable or something, and unwired, having a wireless nic card installed,
so in my case there is a en0 and a en1. So if I only wanted to intercept
the packets from the wireless card, I was wondering if there was some
way I could do that. But it sounds like maybe not.
Thanks for the information
Carl
-----Original Message-----
From: darwin-kernel-bounces+csmith=email@hidden
[mailto:darwin-kernel-bounces+csmith=email@hidden]
On Behalf Of Justin Walker
Sent: Monday, April 11, 2005 7:50 PM
To: darwin-kernel Dev
Subject: Re: Interface filtering
On Apr 11, 2005, at 16:23, Carl Smith wrote:
> I have my Ethernet interface filtering in place and am trapping the
> packets as they come through the interface filter, I was just
wondering
> if there was some way to tell which packets from the interface may be
> from a wireless connection or not?
Since you are using an interface filter, then the packets you get from
a specific interface are either all from a wireless connection, or none
are. Perhaps I am missing the point of your question.
> In my filter I am passed a struct ifnet and the mbuf. I see that in
the
> struct ifnet it gives me the interface name, i.e. 'en', 'lo' and so
on,
> and with this I was just wondering if there is some variable in the
> struct that might also tell me if it is wireless or not.
There is nothing in the name that will give you a hint, and all will
identified as ethernet, at the "BSD network device" layer.
There is probably a mechanism available to distinguish wireless devices
from others, at the IOKit layer, but I don't know what it is (perhaps
the archives will tell). There is provision for maintaining this info
at the BSD/network layer (the if_data substructure of the ifnet
structure), but I don't know that this is ever filled in, and in any
case, this would be done by the driver, so I can't say you can count on
it.
Anyone else?
Regards,
Justin
--
Justin C. Walker, Curmudgeon-At-Large
Institute for General Semantics
--------
"Weaseling out of things is what separates us from the animals.
Well, except the weasel."
- Homer J Simpson
--------
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