Date: Wed, 24 Nov 2010 10:54:38 -0800 From: Weongyo Jeong <weongyo.jeong@gmail.com> To: Andrew Thompson <thompsa@FreeBSD.org> Cc: freebsd-usb@FreeBSD.org, Jung-uk Kim <jkim@FreeBSD.org> Subject: Re: [RFC] USBdump patches Message-ID: <20101124185438.GM92881@weongyo> In-Reply-To: <AANLkTi==szVY%2B=ForwwYxqL1fE7CG9pecYiDAx4Gtw5-@mail.gmail.com> References: <AANLkTinaUNi3FGRiOkeTN2FKx3ybqE=F3W6%2BsV8qVCTf@mail.gmail.com> <201011231852.40484.jkim@FreeBSD.org> <20101124001832.GI92881@weongyo> <201011231936.57818.jkim@FreeBSD.org> <AANLkTi=D5Spta67JfA%2BSXh2VF8dDV_aKN%2BgHYF01Znb4@mail.gmail.com> <20101124054659.GL92881@weongyo> <AANLkTi==szVY%2B=ForwwYxqL1fE7CG9pecYiDAx4Gtw5-@mail.gmail.com>
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On Wed, Nov 24, 2010 at 07:35:30PM +1300, Andrew Thompson wrote: > On 24 November 2010 18:46, Weongyo Jeong <weongyo.jeong@gmail.com> wrote: > > On Wed, Nov 24, 2010 at 01:59:47PM +1300, Andrew Thompson wrote: > >> On 24 November 2010 13:36, Jung-uk Kim <jkim@freebsd.org> wrote: > >> > On Tuesday 23 November 2010 07:18 pm, Weongyo Jeong wrote: > >> >> - BPF was normally for ethernet frames (most operations were > >> >> based on mbuf including the machine filter and there were a lot of > >> >> assumptions the input buffer is mbuf type. For example, handling > >> >> BPF_LD|BPF_W|BPF_ABS). However the USB packet isn't like mbuf > >> >> style that it's just a linear buffer. So the most important code > >> >> or assumption wasn't compatible. > >> > > >> > BPF can deal with linear buffer just fine. For example, ng_bpf(4) > >> > does it. Please see sys/netgraph/ng_bpf.c. > >> > > >> >> - Just making the patch for BPF code, it looked like a trick or > >> >> a hack to me because I couldn't define what BPF should be. > >> > > >> > If you don't want to touch bpf.c for some reason, netgraph(4) (-> > >> > ng_bpf) may be an alternate solution for you. > >> > > >> >> - I could not define BPF exactly myself that what BPF should > >> >> cover. I agreed with that BPF is for ethernet packet filtering but > >> >> could not make sure myself that BPF could cover USB packets. > >> > > >> > BPF is a generic packet filter machine, i.e., bytecode is generic > >> > enough for any type of data stream. > >> > >> I agree that this is the best way forward, if it can be achieved. > > > > Attached is what I really wanted to do. USB pf is greatly simplified > > and perfectly satisfy me. It'll fully benefit from changes of BPF code. > > > > I'll commit this version into HEAD if no objections. > > Looks good. Is this compatible with the wireshark pcap format? Not yet. I think it could happen soon. regards, Weongyo Jeong
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