Improve mechanism for using loopback interface as BVI for BDs

When loopback interface is configured as BVI, instead of changing its
output node from loopN-output to l2-input, the loopN-output node is now
kept while its next tx node is changed from ethernet-input to l2-input.
The packet setup previously done in bvi_to_l2 as part of l2-input is now
performed in the loop output node.

This change adds an extra node in the BVI output path but provides the
following improvements:
1. IP address/route created on loopback prior to it being configured as
   BVI will still work properly. The requirement to (re)configure IP/route
   on loopback after it is configured as BVI is removed.
2. The output stats for loopback interfaces are always provided irrespective
   of their BVI configuration.
3. The loopback-BVI output stats can be batch updated outside the packet
   loop in output node, instead of per packet update in l2-input node,
   making l2-input node more efficient for BVI packets.
4. Restore original node property as implemented in node.c function
   vlib_node_add_next_with_slot() where next node indices stored in next
   slots of each node will remain unique.
5. Packet trace for BVI output includes loopN output node which provides
   useful packet data.

Change-Id: I7f5bc72ef953a367363a179088210596881f9e73
Signed-off-by: John Lo <loj@cisco.com>

1 files changed, 0 insertions, 29 deletions

diff --git a/vnet/vnet/l2/l2_bvi.h b/vnet/vnet/l2/l2_bvi.h
index ca5673373fb..b3b20d63104 100644
--- a/vnet/vnet/l2/l2_bvi.h
+++ b/vnet/vnet/l2/l2_bvi.h
@@ -86,35 +86,6 @@ l2_to_bvi (vlib_main_t * vlib_main,
   return TO_BVI_ERR_OK;
 }
 
-
-// Prepare a packet that was sent to the BVI interface for L2 processing.
-
-static_always_inline void 
-bvi_to_l2 (vlib_main_t * vlib_main,
-           vnet_main_t * vnet_main,
-           u32 cpu_index,
-           vlib_buffer_t * b0,
-           u32 bvi_sw_if_index)
-{
-  // Set the input interface to be the BVI interface
-  vnet_buffer(b0)->sw_if_index[VLIB_RX] = bvi_sw_if_index;
-  vnet_buffer(b0)->sw_if_index[VLIB_TX] = ~0;
-
-  // Update l2_len in packet which is expected by l2 path, 
-  // including l2 tag push/pop code on output
-  vnet_update_l2_len(b0);
-
-  // increment BVI TX interface stat
-  vlib_increment_combined_counter 
-      (vnet_main->interface_main.combined_sw_if_counters
-       + VNET_INTERFACE_COUNTER_TX,
-       cpu_index,
-       bvi_sw_if_index,
-       1,
-       vlib_buffer_length_in_chain (vlib_main, b0));
-}
-
-
 void
 l2bvi_register_input_type (vlib_main_t * vm,
                            ethernet_type_t type,