net: ip_gre: do not report erspan_ver for gre or gretap

[ Upstream commit 2bdf700e538828d6456150b9319e5f689b062d54 ]

Report erspan version field to userspace in ipgre_fill_info just for
erspan tunnels. The issue can be triggered with the following reproducer:

$ip link add name gre1 type gre local 192.168.0.1 remote 192.168.1.1
$ip link set dev gre1 up
$ip -d link sh gre1
13: gre1@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1476 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/gre 192.168.0.1 peer 192.168.1.1 promiscuity 0 minmtu 0 maxmtu 0
    gre remote 192.168.1.1 local 192.168.0.1 ttl inherit erspan_ver 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1

Fixes: f551c91de262 ("net: erspan: introduce erspan v2 for ip_gre")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 6812761..a3f7744 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1466,9 +1466,23 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
        struct ip_tunnel_parm *p = &t->parms;
        __be16 o_flags = p->o_flags;
 
-       if ((t->erspan_ver == 1 || t->erspan_ver == 2) &&
-           !t->collect_md)
-               o_flags |= TUNNEL_KEY;
+       if (t->erspan_ver == 1 || t->erspan_ver == 2) {
+               if (!t->collect_md)
+                       o_flags |= TUNNEL_KEY;
+
+               if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
+                       goto nla_put_failure;
+
+               if (t->erspan_ver == 1) {
+                       if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
+                               goto nla_put_failure;
+               } else {
+                       if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
+                               goto nla_put_failure;
+                       if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
+                               goto nla_put_failure;
+               }
+       }
 
        if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
            nla_put_be16(skb, IFLA_GRE_IFLAGS,
@@ -1504,19 +1518,6 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
                        goto nla_put_failure;
        }
 
-       if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
-               goto nla_put_failure;
-
-       if (t->erspan_ver == 1) {
-               if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
-                       goto nla_put_failure;
-       } else if (t->erspan_ver == 2) {
-               if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
-                       goto nla_put_failure;
-               if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
-                       goto nla_put_failure;
-       }
-
        return 0;
 
 nla_put_failure: