From mboxrd@z Thu Jan  1 00:00:00 1970
From: Atzm Watanabe <atzm@stratosphere.co.jp>
Subject: Re: [PATCH iproute2] iplink: do not require assigning negative ifindex at link creation
Date: Wed, 01 Oct 2014 13:30:28 +0900
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Cc: netdev <netdev@vger.kernel.org>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Stephen Hemminger <stephen@networkplumber.org>
To: Cong Wang <cwang@twopensource.com>
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At Tue, 30 Sep 2014 11:26:04 -0700,
Cong Wang wrote:
> 
> On Tue, Sep 30, 2014 at 4:10 AM, Atzm Watanabe <atzm@stratosphere.co.jp> wrote:
> > Since commit 3c682146aeff, iplink requires assigning negative
> > ifindex (-1) to the kernel when creating interface without
> > specifying index.
> >
> > Cc: Cong Wang <xiyou.wangcong@gmail.com>
> > Signed-off-by: Atzm Watanabe <atzm@stratosphere.co.jp>
> > ---
> >  ip/iplink.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/ip/iplink.c b/ip/iplink.c
> > index cb9c870..de6b2a9 100644
> > --- a/ip/iplink.c
> > +++ b/ip/iplink.c
> > @@ -689,7 +689,10 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
> >                         addattr_l(&req.n, sizeof(req), IFLA_LINK, &ifindex, 4);
> >                 }
> >
> > -               req.i.ifi_index = index;
> > +               if (index <= 0)
> > +                       req.i.ifi_index = 0;
> > +               else
> > +                       req.i.ifi_index = index;
> 
> How about checking if it is -1?
> 
> if (index == -1)
>    req.i.ifi_index = 0;
> else
>    req.i.ifi_index = index;

Agreed, will fix.

Because iplink_parse() forbids specifying negative index, it will be
actually same.  But your suggestion seems more nicer than my patch.

Thanks.