Handling packets from kernel click to user process

[Brecht Vermeulen]

Hi Eddie,

thanks for your information.

> > - in the manpage of tolinuxsniffers : 'Hands packets to any packet
> > sniffers registered with Linux, such as packet sockets.'
> > What are exactly 'packet sockets' ?
> 
> man 7 packet. For code, check out userlevel FromDevice.
> 

I've done some investigation and I've seen that the libpcap library is
based on packet sockets (in case of Linux) or Berkeley Packet Filters
for some other OSs.

Am I correct by saying that the Click FromDevice (userlevel) is written
directly on top of the packet sockets in the case of Linux (for other
systems via libpcap) because you could then use non blocking sockets and
that for Linux libpcap isn't needed (neither for compilation nor for
running userlevel click) ?

Maybe it would be interesting to mark this in the INSTALL file (or in
the FAQ file), now it says only : 

The user-level version of Click should compile and run on any Intel x86
Unix system that has the pcap library. (The pcap library is necessary to
communicate with the network.


For my kernel to userlevel communication, I will use the pcap library
combined with tolinuxsniffers for now, because the hand over has to
happen only rarely. Starting in September, a student will work on a
CORBA monitoring platform (where the sniffing and classification will be
based on click because it doesn't suffer from receive livelock and the
effective handling of the interesting packets will be done in
userspace).

regards,
Brecht