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

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>

1 files changed, 17 insertions, 16 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 3978f807fa8b..6ae89f2b541b 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1457,9 +1457,23 @@ 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,
@@ -1495,19 +1509,6 @@ 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: