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/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index 207d968a650..e4d8fc0ea88 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -239,6 +239,8 @@ void
 ip6_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
 {
   ip6_main_t *im = &ip6_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);
 
@@ -264,6 +266,11 @@ ip6_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
 
   vnet_feature_enable_disable ("ip6-multicast", "ip6-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--;
 }
 
 /* get first interface address */