[erlang-questions] low level packet access from erlang

[Garry Hodgson]

i am building an experimental firewall of sorts,
and need to be able to access incoming packets
directly, so i can muck around with low level
src/dst/ports/etc information. it looks like the standard
modules handle the low level things for me, such that
i by the time i see an incoming message, the low level
details are lost.

how can i arrange access to the lower level information
(ignoring performance issues for now)?

i see like mentioned a way in an old (2001) thread:
http://www.trapexit.org/forum/viewtopic.php?p=4258&sid=4469db61020efe9100e1e1c2504bfc8c
but the link to bluetail where his code was doesn't exist anymore.

i've read the ei/pcap approach presented here:
http://blog.listincomprehension.com/2009/12/erlang-packet-sniffer-using-ei-and.html

but i don't want to just sniff packets, but intercept them.

i'd appreciate any insights into how to tackle this.

-- 
Garry Hodgson
AT&T Chief Security Office (CSO)

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