[PATCH net 3/3] gre: receive also TEB packets for lwtunnels

[Jiri Benc]

For ipgre interfaces in collect metadata mode, receive also traffic with
encapsulated Ethernet headers. The lwtunnel users are supposed to sort this
out correctly. This allows to have mixed Ethernet + L3-only traffic on the
same lwtunnel interface.

To keep backwards compatibility and prevent any surprises, gretap interfaces
have priority in receiving packets with Ethernet headers.

Signed-off-by: Jiri Benc <jb...@redhat.com>
---
 include/net/ip_tunnels.h |  1 +
 net/ipv4/ip_gre.c        | 34 +++++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 56050f913339..ac8d6822072e 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -161,6 +161,7 @@ struct tnl_ptk_info {
 
 #define PACKET_RCVD    0
 #define PACKET_REJECT  1
+#define PACKET_NEXT    2
 
 #define IP_TNL_HASH_BITS   7
 #define IP_TNL_HASH_SIZE   (1 << IP_TNL_HASH_BITS)
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index f973e0a58993..ccd6b098928d 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -379,19 +379,13 @@ static __be32 tunnel_id_to_key(__be64 x)
 #endif
 }
 
-static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
+static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
+                      struct ip_tunnel_net *itn)
 {
-       struct net *net = dev_net(skb->dev);
        struct metadata_dst *tun_dst = NULL;
-       struct ip_tunnel_net *itn;
        const struct iphdr *iph;
        struct ip_tunnel *tunnel;
 
-       if (tpi->proto == htons(ETH_P_TEB))
-               itn = net_generic(net, gre_tap_net_id);
-       else
-               itn = net_generic(net, ipgre_net_id);
-
        iph = ip_hdr(skb);
        tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
                                  iph->saddr, iph->daddr, tpi->key);
@@ -412,7 +406,29 @@ static int ipgre_rcv(struct sk_buff *skb, const struct 
tnl_ptk_info *tpi)
                ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
                return PACKET_RCVD;
        }
-       return PACKET_REJECT;
+       return PACKET_NEXT;
+}
+
+static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
+{
+       struct net *net = dev_net(skb->dev);
+       struct ip_tunnel_net *itn;
+       int res;
+
+       if (tpi->proto == htons(ETH_P_TEB))
+               itn = net_generic(net, gre_tap_net_id);
+       else
+               itn = net_generic(net, ipgre_net_id);
+
+       res = __ipgre_rcv(skb, tpi, itn);
+       if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) {
+               /* ipgre tunnels in collect metadata mode should receive
+                * also ETH_P_TEB traffic
+                */
+               itn = net_generic(net, ipgre_net_id);
+               res = __ipgre_rcv(skb, tpi, itn);
+       }
+       return res;
 }
 
 static int gre_rcv(struct sk_buff *skb)
-- 
1.8.3.1