netdev - Re: [RFC 03/12] net: cls_bpf: limit hardware offload by software-only flag

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Message-ID: <20160601220520.717fb5f8@jkicinski-Precision-T1700>
Date:	Wed, 1 Jun 2016 22:05:20 +0100
From:	Jakub Kicinski <jakub.kicinski@...ronome.com>
To:	Daniel Borkmann <daniel@...earbox.net>
Cc:	netdev@...r.kernel.org, ast@...nel.org,
	dinan.gunawardena@...ronome.com
Subject: Re: [RFC 03/12] net: cls_bpf: limit hardware offload by
 software-only flag

On Wed, 01 Jun 2016 21:40:23 +0200, Daniel Borkmann wrote:
> > diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
> > index f4297c8a42fe..93a86edf3bd8 100644
> > --- a/include/uapi/linux/pkt_cls.h
> > +++ b/include/uapi/linux/pkt_cls.h
> > @@ -395,6 +395,7 @@ enum {
> >   	TCA_BPF_FD,
> >   	TCA_BPF_NAME,
> >   	TCA_BPF_FLAGS,
> > +	TCA_BPF_GEN_TCA_FLAGS,  
> 
> Small nit for the non-RFC set: I'd simply name that TCA_BPF_FLAGS_GEN.

OK!

> > @@ -400,8 +406,11 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
> >
> >   		have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
> >   	}
> > +	if (tb[TCA_BPF_GEN_TCA_FLAGS])
> > +		gen_flags = nla_get_u32(tb[TCA_BPF_GEN_TCA_FLAGS]);
> >
> >   	prog->exts_integrated = have_exts;
> > +	prog->gen_flags = gen_flags & CLS_BPF_SUPPORTED_GEN_FLAGS;  
> 
> Invalid flags should probably be rejected here with -EINVAL or something.

Indeed, that would be more in line with what is done for "the other"
flags attribute, but not so much with how flower and u32 handles
flags. I like the stricter approach better, though, so unless someone
speaks up I'll do as you suggest.