From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Sutter Subject: Re: [PATCH iproute2] vxlan: show correct ttl inherit info Date: Thu, 27 Sep 2018 11:27:45 +0200 Message-ID: <20180927092745.GV14666@orbyte.nwl.cc> References: <1538033316-32312-1-git-send-email-liuhangbin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, Stephen Hemminger , David Ahern To: Hangbin Liu Return-path: Received: from orbyte.nwl.cc ([151.80.46.58]:50908 "EHLO orbyte.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727617AbeI0PpG (ORCPT ); Thu, 27 Sep 2018 11:45:06 -0400 Content-Disposition: inline In-Reply-To: <1538033316-32312-1-git-send-email-liuhangbin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi Hangbin, On Thu, Sep 27, 2018 at 03:28:36PM +0800, Hangbin Liu wrote: > We should only show ttl inherit when IFLA_VXLAN_TTL_INHERIT supplied. > Otherwise show the ttl number, or auto when it is 0. > > Signed-off-by: Hangbin Liu > --- > ip/iplink_vxlan.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > diff --git a/ip/iplink_vxlan.c b/ip/iplink_vxlan.c > index 831f39a..7fc0e2b 100644 > --- a/ip/iplink_vxlan.c > +++ b/ip/iplink_vxlan.c > @@ -145,7 +145,7 @@ static int vxlan_parse_opt(struct link_util *lu, int argc, char **argv, > NEXT_ARG(); > check_duparg(&attrs, IFLA_VXLAN_TTL, "ttl", *argv); > if (strcmp(*argv, "inherit") == 0) { > - addattr_l(n, 1024, IFLA_VXLAN_TTL_INHERIT, NULL, 0); > + addattr(n, 1024, IFLA_VXLAN_TTL_INHERIT); So for VXLAN, the attribute is just added but with a zero value. Looking at respective kernel code, this seems fine. Now I wonder why for Geneve, you set the value to 1 and when displaying explicitly check whether the attribute is there *and* non-zero. OK, looks like Geneve driver always exports IFLA_GENEVE_TTL_INHERIT. Oddly, I can't find where VXLAN driver in kernel does export the IFLA_VXLAN_TTL_INHERIT attribute. Am I missing something? Do you know why handling of the attributes in both drivers differ? Cheers, Phil