--------
> (sorry i lost the original posting)
>
> BSDi BPF extension is part of BSDi packet filter ("ipfw", don't confuse
> it with FreeBSD one with the same name). i've contacted BSDi guy if
> they could release the code to the public, so please hold for a moment
> on the official answer. time have passed since he gave me an OK to
> release BSDi BPF, his management have changed (WindRiver chewed up
> BSDi and stuff), so we need a positive response from him before making
> any action.
>
> BSDi BPF extension has a few good things and a few bad things:
> good things:
> it can do "protochain" in one BPF insn. backward jump is
> prohibited in kernel BPF interpreter to avoid infinite loop,
> so BSDi BPF has a BPF insn to do "protochain" operation.
>
> it has 128bit registers, which would help IPv6 parsing.
>
> bad things:
> BSDi BPF changed interpretation of some additional BPF insn
> (and new interpretation like 128bit register) without having
> any version identification. there's no way to identify
> what version of BPF engine is installed in the kernel, so we
> can't make libpcap compiler to work on pre-BSDi and BSDi BPF
> engine.
>
> the "bad things" part really bothers me, as if we switch to BSDi BPF,
> we require every operating system to switch their kernel BPF evaluation
> engine to BSDi one. it is not a smooth transition, there needs to be
> a big "flag day".
>
>itojun
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