gre: build header correctly for collect metadata tunnels

In ipgre (i.e. not gretap) + collect metadata mode, the skb was assumed to
contain Ethernet header and was encapsulated as ETH_P_TEB. This is not the
case, the interface is ARPHRD_IPGRE and the protocol to be used for
encapsulation is skb->protocol.

Fixes: 2e15ea390e6f4 ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d0abde4236af..f973e0a58993 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -523,7 +523,8 @@ static struct rtable *gre_get_rt(struct sk_buff *skb,
         return ip_route_output_key(net, fl);
 }
 
-static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
+static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
+                        __be16 proto)
 {
         struct ip_tunnel_info *tun_info;
         const struct ip_tunnel_key *key;
@@ -575,7 +576,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
         }
 
         flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
-        build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
+        build_header(skb, tunnel_hlen, flags, proto,
                      tunnel_id_to_key(tun_info->key.tun_id), 0);
 
         df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
@@ -616,7 +617,7 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
         const struct iphdr *tnl_params;
 
         if (tunnel->collect_md) {
-                gre_fb_xmit(skb, dev);
+                gre_fb_xmit(skb, dev, skb->protocol);
                 return NETDEV_TX_OK;
         }
 
@@ -660,7 +661,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
         struct ip_tunnel *tunnel = netdev_priv(dev);
 
         if (tunnel->collect_md) {
-                gre_fb_xmit(skb, dev);
+                gre_fb_xmit(skb, dev, htons(ETH_P_TEB));
                 return NETDEV_TX_OK;
         }