From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: [PATCH] net: ipv4: fix l3slave check for index returned in IP_PKTINFO Date: Wed, 13 Sep 2017 17:11:37 -0700 Message-ID: <1505347897-27422-1-git-send-email-dsahern@gmail.com> Cc: David Ahern To: netdev@vger.kernel.org Return-path: Received: from mail-pg0-f66.google.com ([74.125.83.66]:37010 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751173AbdINALq (ORCPT ); Wed, 13 Sep 2017 20:11:46 -0400 Received: by mail-pg0-f66.google.com with SMTP id v5so807230pgn.4 for ; Wed, 13 Sep 2017 17:11:45 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: rt_iif is only set to the actual egress device for the output path. The recent change to consider the l3slave flag when returning IP_PKTINFO works for local traffic (the correct device index is returned), but it broke the more typical use case of packets received from a remote host always returning the VRF index rather than the original ingress device. Update the fixup to consider l3slave and rt_iif actually getting set. Fixes: 1dfa76390bf05 ("net: ipv4: add check for l3slave for index returned in IP_PKTINFO") Signed-off-by: David Ahern --- net/ipv4/ip_sockglue.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index e558e4f9597b..a599aa83fdad 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1207,7 +1207,6 @@ static int do_ip_setsockopt(struct sock *sk, int level, void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb) { struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb); - bool l3slave = ipv4_l3mdev_skb(IPCB(skb)->flags); bool prepare = (inet_sk(sk)->cmsg_flags & IP_CMSG_PKTINFO) || ipv6_sk_rxinfo(sk); @@ -1221,8 +1220,13 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb) * (e.g., process binds socket to eth0 for Tx which is * redirected to loopback in the rtable/dst). */ - if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX || l3slave) + struct rtable *rt = skb_rtable(skb); + bool l3slave = ipv4_l3mdev_skb(IPCB(skb)->flags); + + if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) pktinfo->ipi_ifindex = inet_iif(skb); + else if (l3slave && rt && rt->rt_iif) + pktinfo->ipi_ifindex = rt->rt_iif; pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb); } else { -- 2.1.4