Re: [PATCH net-next v3] net: introduce SO_BPF_EXTENSIONS

[David Miller <davem@davemloft.net>]

From: Michal Sekletar <msekleta@redhat.com>
Date: Fri, 17 Jan 2014 17:09:45 +0100

> For user space packet capturing libraries such as libpcap, there's
> currently only one way to check which BPF extensions are supported
> by the kernel, that is, commit aa1113d9f85d ("net: filter: return
> -EINVAL if BPF_S_ANC* operation is not supported"). For querying all
> extensions at once this might be rather inconvenient.
> 
> Therefore, this patch introduces a new option which can be used as
> an argument for getsockopt(), and allows one to obtain information
> about which BPF extensions are supported by the current kernel.
> 
> As David Miller suggests, we do not need to define any bits right
> now and status quo can just return 0 in order to state that this
> versions supports SKF_AD_PROTOCOL up to SKF_AD_PAY_OFFSET. Later
> additions to BPF extensions need to add their bits to the
> bpf_tell_extensions() function, as documented in the comment.
> 
> Signed-off-by: Michal Sekletar <msekleta@redhat.com>
> Cc: David Miller <davem@davemloft.net>
> Reviewed-by: Daniel Borkmann <dborkman@redhat.com>

Applied, thanks.