From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [PATCH net-next v2] net: Add table id from route lookup to route response Date: Wed, 2 Sep 2015 13:41:08 -0700 Message-ID: <55E75EE4.2050602@gmail.com> References: <20150902190836.GD20527@pox.localdomain> <1441224980-6201-1-git-send-email-dsa@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: David Ahern , netdev@vger.kernel.org Return-path: Received: from mail-pa0-f45.google.com ([209.85.220.45]:35559 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755419AbbIBUlL (ORCPT ); Wed, 2 Sep 2015 16:41:11 -0400 Received: by pacfv12 with SMTP id fv12so22670612pac.2 for ; Wed, 02 Sep 2015 13:41:10 -0700 (PDT) In-Reply-To: <1441224980-6201-1-git-send-email-dsa@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 09/02/2015 01:16 PM, David Ahern wrote: > IPv4 ABI has the table hardcoded as RT_TABLE_MAIN regardless of the table > hit for the route lookup. Add the table using a new attribute, > RTA_TABLE_LOOKUP, to maintain the ABI yet return the right table id. > > Signed-off-by: David Ahern > --- > > Thomas: Something like this? > > The current ABI is returning wrong data in some cases; that seems worse > to me than breaking the ABI. > > include/uapi/linux/rtnetlink.h | 1 + > net/ipv4/route.c | 5 +++++ > net/ipv6/route.c | 4 ++++ > 3 files changed, 10 insertions(+) > > diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h > index 702024769c74..5add1468350a 100644 > --- a/include/uapi/linux/rtnetlink.h > +++ b/include/uapi/linux/rtnetlink.h > @@ -310,6 +310,7 @@ enum rtattr_type_t { > RTA_PREF, > RTA_ENCAP_TYPE, > RTA_ENCAP, > + RTA_TABLE_LOOKUP, /* table hit for fib lookup */ > __RTA_MAX > }; > > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index 92acc95b7578..95454c368e66 100644 > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -2328,6 +2328,11 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, > r->rtm_table = RT_TABLE_MAIN; > if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN)) > goto nla_put_failure; > + > + if (rt->rt_table_id && rt->rt_table_id != RT_TABLE_MAIN && > + nla_put_u32(skb, RTA_TABLE_LOOKUP, rt->rt_table_id)) > + goto nla_put_failure; > + > r->rtm_type = rt->rt_type; > r->rtm_scope = RT_SCOPE_UNIVERSE; > r->rtm_protocol = RTPROT_UNSPEC; Why not implement this this same for IPv4 and IPv6? It looks like it is only included if it is non-zer and not MAIN in the above case, and then below as long as a table ID is non-zero you are setting the value. Why not just include the value in all cases where it is defined just like for IPv6? > diff --git a/net/ipv6/route.c b/net/ipv6/route.c > index f45cac6f8356..3c5d3a50bb7b 100644 > --- a/net/ipv6/route.c > +++ b/net/ipv6/route.c > @@ -2922,6 +2922,10 @@ static int rt6_fill_node(struct net *net, > rtm->rtm_table = table; > if (nla_put_u32(skb, RTA_TABLE, table)) > goto nla_put_failure; > + > + if (table && nla_put_u32(skb, RTA_TABLE_LOOKUP, table)) > + goto nla_put_failure; > + > if (rt->rt6i_flags & RTF_REJECT) { > switch (rt->dst.error) { > case -EINVAL: >