| Packet filtering is one of the things drivers do. Are you asking what you
see as a user of the driver, or are you looking at the case of writing a
different driver and being a user of the hardware directly?
If the former, the answer depends on the driver. If the latter, it depends
on the hardware. Either way, there isn't necessarily a general answer.
As for the CAM setup, the driver does that: when you tell it you want to listen
to a particular multicast address, it updates the CAM as needed to make sure
that address is in the CAM. (Exception: DEMFA, where you tell the adapter
what addresses plus protocols you want, and it deals with the CAM internally.
Doesn't make much difference as far as the driver goes.)
paul
|
| Let me clarify what I am refering to by 'packetfilter'. Running
on Ultrix 4.2 with a DECstation 5200, by typing 'man packetfilter'
you get the following description:
"The packet filter pseudo-device driver provides a raw interface
to Ethernets and similar network data link layers. Packets
received that are not used by the kernel ... are available through
this mechanism...."
To use this, you do a 'pfopen' then reads and writes. To
select packets, you provide a filter command sequence
using the packet filter command language. (ex: ENF_PUSHZERO etc
)
I am looking for sample code someone has written that specifically
does a 'pfopen' on the FDDI and proceeds to select and send
packets based on a packet filter command sequence.
The advantage of this over using the dli layer is that
you have more access to the underlying protocol stack.
...Cal
|