interface: Prevent bad inner-dot1q any exact-match configuration

Someone much more knowledgeable than I wrote:

    For L3 IP forwarding, any VLAN tags on a packet must be exact
    match to a sub-interface which means both outer and inner VLAN
    tag IDs must be exact-matched to specific values defined of that
    sub-interface.  Without exact match on a L3 sub-interface, VPP
    has no mechanism to know what VLAN tags to use for packet output,
    such as ARP request packets or IP packets, on that sub-interface.

    Thus, sub-interface with "inner-dot1q any" is not an exact match
    sub-interface by definition since no match is present on inner
    tag.

While in the area, fix a memory leak that would ensue on poorly
configured interfaces.

Change-Id: I8d17a96dbca3e3724c297ecc935ca61764e6ce2e
Type: fix
Signed-off-by: Jon Loeliger <jdl@netgate.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/vnet/interface.c b/src/vnet/interface.c
index b2166dcebae..5ee3a74fe0b 100644
--- a/src/vnet/interface.c
+++ b/src/vnet/interface.c
@@ -582,6 +582,16 @@ vnet_create_sw_interface (vnet_main_t * vnm, vnet_sw_interface_t * template,
   vnet_hw_interface_t *hi;
   vnet_device_class_t *dev_class;
 
+  if (template->sub.eth.flags.two_tags == 1
+      && template->sub.eth.flags.exact_match == 1
+      && (template->sub.eth.flags.inner_vlan_id_any == 1
+	  || template->sub.eth.flags.outer_vlan_id_any == 1))
+    {
+      error = clib_error_return (0,
+				 "inner-dot1q any exact-match is unsupported");
+      return error;
+    }
+
   hi = vnet_get_sup_hw_interface (vnm, template->sup_sw_if_index);
   dev_class = vnet_get_device_class (vnm, hi->dev_class_index);