Re: filtering packtes before OS takes care about them
From: Asim Shankar <hidden>
Date: 2005-02-28 20:09:56
i need a possibility to catch IP4 packets (from ethernet devices) before OS' netmodules (IP, UDP, TCP, ICMP, ARP, ROUTE, NETFILTER ...) takes care about them and * to delete them from input buffer such that OS' netmodules can't receive them * to modify packet headers and move packets to interface related output buffers * to keep them in input buffers such that OS' netmodules can take care about them.
You can process packets even before ip_rcv() gets them by registering your own packet handler (struct packet_type) using dev_add_pack(). I have a small sample at: http://limnos.csrd.uiuc.edu/notes/code-samples/samples/kernel/packet_type/packet_type_test.c This may not be the cleanest way, but it isn't that dirty either. Also see: http://www.phrack.org/show.php?p=55&a=12 -- Asim