Could These improvement be appiled to netbsd-1-6 branch?

> Module Name:	src
> Committed By:	darrenr
> Date:		Sat Apr 10 23:31:52 UTC 2004
> 
> Modified Files:
> 	src/sys/net: bpf.c bpf.h bpfdesc.h
> 
> Log Message:
> Fix bpf so that select will return for a timeout (from FreeBSD.)
> 
> Fix the behaviour of BIOCIMMEDIATE (fix from LBL BPF code via FreeBSD.)
> 
> In bpf_mtap(), optimise the calling of bpf_filter() and catchpacket()
> based on whether or not the entire packet is in one mbuf (based on
> similar change FreeBSD but fixes BIOC*SEESENT issue with that.)
> 
> Copy the implementation of BIOCSSEESENT, BIOCGSEESENT by FreeBSD.
> 
> Review Assistance: Guy Harris
> 
> PRs: kern/8674, kern/12170

-- 
Takahiro Kambe <taca@back-street.net>