On Wed, Nov 24, 2010 at 01:59:47PM +1300, Andrew Thompson wrote:
> On 24 November 2010 13:36, Jung-uk Kim <j...@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.
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