*BSD News Article 36688


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From: phowlett@angus.ASG.unb.ca (Peter Howlett)
Newsgroups: comp.os.386bsd.questions
Subject: BPF Filter
Date: 7 Oct 1994 15:10:06 GMT
Organization: University of New Brunswick
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Message-ID: <373oce$pv0@sol.sun.csd.unb.ca>
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Has anyone ever tried _writing_ to a bpf filter? The filter works
great to read packets. To write, I build an ethernet packet in a
buffer and try to write to the device. The write never returns.
Hmmm. The man page devotes one short paragraph to writing, simply
saying that it can be done on ethernet and slip and also that its
a non-buffered write.

In case you are wondering, I tried opening the device(s) two ways.
The first way the device is opened O_RDWR. The second way two
devices are opened, one O_RDONLY, one O_WRONLY and both devices
attached to the same interface. Same result with both methods.

Any thoughts?

--------------------------------------------------------------------
Peter Howlett			Atlantic Systems Group
E-Mail: phowlett@ASG.unb.ca	Fredericton, N.B. Canada
http://www.ASG.unb.ca		Phone: (506) 453-3505
PGP Key on Personal Home Page	Fax:   (506) 453-5004