gre: do not keep the GRE header around in collect medata mode

For ipgre interface in collect metadata mode, it doesn't make sense for the
interface to be of ARPHRD_IPGRE type. The outer header of received packets
is not needed, as all the information from it is present in metadata_dst. We
already don't set ipgre_header_ops for collect metadata interfaces, which is
the only consumer of mac_header pointing to the outer IP header.

Just set the interface type to ARPHRD_NONE in collect metadata mode for
ipgre (not gretap, that still correctly stays ARPHRD_ETHER) and reset
mac_header.

Fixes: a64b04d86d14 ("gre: do not assign header_ops in collect metadata mode")
Fixes: 2e15ea390e6f4 ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 205a2b8a5a84..4cc84212cce1 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -398,7 +398,10 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
                                   iph->saddr, iph->daddr, tpi->key);
 
         if (tunnel) {
-                skb_pop_mac_header(skb);
+                if (tunnel->dev->type != ARPHRD_NONE)
+                        skb_pop_mac_header(skb);
+                else
+                        skb_reset_mac_header(skb);
                 if (tunnel->collect_md) {
                         __be16 flags;
                         __be64 tun_id;
@@ -1031,6 +1034,8 @@ static void ipgre_netlink_parms(struct net_device *dev,
                 struct ip_tunnel *t = netdev_priv(dev);
 
                 t->collect_md = true;
+                if (dev->type == ARPHRD_IPGRE)
+                        dev->type = ARPHRD_NONE;
         }
 }