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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Alexey Kodanev <alexey.kodanev@oracle.com>,
        David Ahern <dsahern@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.2 055/143] ipv4: mpls: fix mpls_xmit for iptunnel
Date:   Wed,  4 Sep 2019 19:53:18 +0200
Message-Id: <20190904175316.228828422@linuxfoundation.org>
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From: Alexey Kodanev <alexey.kodanev@oracle.com>

[ Upstream commit 803f3e22ae10003a83c781498c0ac34cfe3463ff ]

When using mpls over gre/gre6 setup, rt->rt_gw4 address is not set, the
same for rt->rt_gw_family.  Therefore, when rt->rt_gw_family is checked
in mpls_xmit(), neigh_xmit() call is skipped. As a result, such setup
doesn't work anymore.

This issue was found with LTP mpls03 tests.

Fixes: 1550c171935d ("ipv4: Prepare rtable for IPv6 gateway")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mpls/mpls_iptunnel.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -133,12 +133,12 @@ static int mpls_xmit(struct sk_buff *skb
 	mpls_stats_inc_outucastpkts(out_dev, skb);
 
 	if (rt) {
-		if (rt->rt_gw_family == AF_INET)
-			err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
-					 skb);
-		else if (rt->rt_gw_family == AF_INET6)
+		if (rt->rt_gw_family == AF_INET6)
 			err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6,
 					 skb);
+		else
+			err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
+					 skb);
 	} else if (rt6) {
 		if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
 			/* 6PE (RFC 4798) */