Re: BSDi BPF extension

[itojun () iijlab net]

> On Fri, Sep 12, 2003 at 07:07:39AM +0900, Jun-ichiro itojun Hagino wrote:
> >      bad things:
> >              BSDi BPF changed interpretation of some additional BPF insn
> >              (and new interpretation like 128bit register) without having
> >              any version identification.
> Which instructions' interpretation did they change (rather than adding
> new interpretations)?

        don't remember, i really need to look at the source (i don't have it
        handy).  maybe it's just additional insn.  anyways, we will know
        when it got released (and we need to worry about it only if it got
        released).

> >              there's no way to identify
> >              what version of BPF engine is installed in the kernel,
>
> True, unfortunately, for BSD/OS.
>
> However, if other BSDs adopt that engine, they should change the version
> from the 1.1 that's in the top-of-tree {Free,Net,Open}BSD to 1.2 or 2.0
> (1.2 if new instructions are added, 2.0 if existing supported
> instructions are changed incompatibly), so that libpcap can do a
> BIOCVERSION to determine whether the kernel's BPF interpreter supports
> the new stuff or not.  (I don't know offhand whether Darwin uses 1.1,
> but I can check it at work tomorrow - I suspect we do.)

        but still, we need to have two gencode.c (or many
        "if (old) this else that" in gencode.c).

itojun
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