Re: pcap_t not writeable on OpenBSD

[Fernando Gont <fernando () gont com ar>]

On 01/10/2012 05:13 PM, Sam Roberts wrote:
> On Mon, Jan 9, 2012 at 8:49 PM, Fernando Gont <fernando () gont com ar> wrote:
> > I'm doing I/O multiplexing with the pcap descriptor, and it turns out
> > that on OpenBSD the underlying descriptor for a pcap_t is never writeable.
> > Note: No problems in Linux and FreeBSD -- so far only in OpenBSD.
>
> Are you capturing, or injecting?

Both.

> Shouldn't you be waiting for it to be readable for capture?

Yes, but I wait for writeability for injecting, to avoid blocking.


> For injection, on linux anyhow, a PF_PACKET device is always
> writeable, but I'm pretty sure it discards packets if you write too
> fast.

Does pcap_inject() or the like block, or does it actually discard the
"exceeding" packets?

Thanks,
-- 
Fernando Gont
e-mail: fernando () gont com ar || fgont () si6networks com
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1



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