[PATCH 4.4 255/312] gre: build header correctly for collect metadata tunnels

From: Greg Kroah-Hartman
Date: Fri May 08 2020 - 09:14:48 EST


From: Jiri Benc <jbenc@xxxxxxxxxx>

commit 2090714e1d6e80979dd6926be22b0de9ca432273 upstream.

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@xxxxxxxxxx>
Acked-by: Pravin B Shelar <pshelar@xxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/ipv4/ip_gre.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -520,7 +520,8 @@ static struct rtable *gre_get_rt(struct
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;
@@ -563,7 +564,7 @@ static void gre_fb_xmit(struct sk_buff *
}

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;
@@ -605,7 +606,7 @@ static netdev_tx_t ipgre_xmit(struct sk_
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;
}

@@ -649,7 +650,7 @@ static netdev_tx_t gre_tap_xmit(struct s
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;
}