ethernet: fix DMAC check and skip unnecessary ones (VPP-1868)

Fix and optimize DMAC check in ethernet-input node to utilize NIC or
driver which support L3 DMAC-filtering mode so that DMAC check can be
bypassed safely for interfaces/sub-interfaces in L3 mode.
Checking of interface in L3-DMAC-filtering state to avoid DMAC check
require the following:
a) Fix interface driver init sequence for devices which supports L3
   DMAC-filtering to indicate its capability and initialize interface
   to L3 DMAC-filtering state.
b) Fix ethernet_set_flags() function and its associated callback
   flags_change() functions registered by various drivers in interface
   infra to provide proper L3 DMAC filtering status.
Maintain interface/sub-interface L3 config count so DMAC checks can be
bypassed if L3 forwarding is not setup on any main/sub-interfaces.

Type: fix
Ticket: VPP-1868

Signed-off-by: John Lo <loj@cisco.com>
Change-Id: I204d90459c13e9e486cfcba4e64e3d479bc9f2ae

1 files changed, 7 insertions, 0 deletions

diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 231912bc5ca..b76da0a248b 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -640,6 +640,8 @@ void
 ip4_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
 {
   ip4_main_t *im = &ip4_main;
+  vnet_main_t *vnm = vnet_get_main ();
+  vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 
   vec_validate_init_empty (im->ip_enabled_by_sw_if_index, sw_if_index, 0);
 
@@ -664,6 +666,11 @@ ip4_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
   vnet_feature_enable_disable ("ip4-multicast", "ip4-not-enabled",
 			       sw_if_index, !is_enable, 0, 0);
 
+  if (is_enable)
+    hi->l3_if_count++;
+  else if (hi->l3_if_count)
+    hi->l3_if_count--;
+
   {
     ip4_enable_disable_interface_callback_t *cb;
     vec_foreach (cb, im->enable_disable_interface_callbacks)