Date: Mon, 8 Sep 2003 11:43:19 +0400 (MSD) From: Dmitry Morozovsky <marck@rinet.ru> To: Peter Pentchev <roam@ringlet.net> Cc: hackers@freebsd.org Subject: Re: if bpf fd's select()able? Message-ID: <20030908114113.A55683@woozle.rinet.ru> In-Reply-To: <20030908070453.GO556@straylight.oblivion.bg> References: <20030907233940.M18589@woozle.rinet.ru> <3F5BB991.2050601@netli.com> <20030908070453.GO556@straylight.oblivion.bg>
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On Mon, 8 Sep 2003, Peter Pentchev wrote: PP> On Sun, Sep 07, 2003 at 04:04:49PM -0700, Lev Walkin wrote: PP> > Dmitry Morozovsky wrote: PP> > >Dear colleagues, PP> > > PP> > >[all below is for 4-STABLE] PP> > > PP> > >I'm trying to write effective arp scanner for multi-interface router (esp. PP> > >multi-vlan); I plan to use multiple bpf devices attached to different PP> > >interfaces emitting ARP requests and filters listening to ARP replies; the PP> > >most PP> > >natural way to multiplex them for me is select(). PP> > > PP> > >However, my tests show that select()ing bpf fd does not lead to trigger PP> > >packets PP> > >available to bpf filter; the process hangs in select state while parallel PP> > >tcpdump process shows packets desired *and* is in bpf state. PP> > > PP> > >Am I missing something "base"? References (surely, I'd already read PP> > >manpages for bpf, pcap and related -- but did I still missed something PP> > >serious?) would be greatly appreciated. PP> > PP> > Yes, you're missing the interactive mode. PP> > PP> > Refer to BIOCIMMEDIATE in the bpf(4) manual page. PP> PP> Also, I believe that for a month or so bpf devices have been able to PP> issue kqueue notifications, too, so - at least for FreeBSD - the "most PP> natural" way might now be kqueue() and not select() :) Thanks Peter, I'm aware of these recent changes; however, I plan to support at least one or two previous security branches, so kqueue ()is not the first option for me. Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------
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