RFC ip_tunnel: specify tunnel type via template

Hi,

The following patchset adds a new field to the tunnel metadata template to restrict the configuration to a given tunnel driver. Currently, a misconfiguration may result in packets going to the wrong tunnel driver.

Although we have the tunnel option flags, they are not mandatory for some tunnel drivers, eg. vxlan, which may use it or not; and gre which does not use them.

This patch updates tc's tunnel action and netfilter's tunnel extension to use this new field. OVS netlink interface has been left unset, although they could be updated to use this.

By extending the existing tc action to support the IP_TUNNEL_INFO_BRIDGE mode, I think it should be possible to expose IP_TUNNEL_TYPE_VLAN too, although this patchset doesn't address this scenario.

The field is initialized to zero, which maps to IP_TUNNEL_TYPE_UNSPEC to retain the existing behaviour, so the existing flexibility is still in place while this new feature is added.

Cc'ing people that git annotate show as dealing with these bits more recently.

Compile tested only.

Comments welcome, thanks.

Pablo Neira Ayuso (3):
ip_tunnel: add type field to struct ip_tunnel_info
net: act_tunnel_key: support for tunnel type
netfilter: nft_tunnel: support for tunnel type

 drivers/net/geneve.c                      |  3 ++-
 drivers/net/vxlan.c                       | 13 +++++++------
 include/net/dst_metadata.h                |  1 +
 include/net/ip_tunnels.h                  | 16 ++++++++++++++++
 include/uapi/linux/netfilter/nf_tables.h  | 10 ++++++++++
 include/uapi/linux/tc_act/tc_tunnel_key.h | 10 ++++++++++
 net/ipv4/ip_gre.c                         |  2 ++
 net/ipv6/ip6_gre.c                        |  2 ++
 net/netfilter/nft_tunnel.c                |  9 ++++++++-
 net/openvswitch/flow_netlink.c            |  1 +
 net/sched/act_tunnel_key.c                |  9 +++++++++
 11 files changed, 68 insertions(+), 8 deletions(-)