/*
 * l2_bvi.h : layer 2 Bridged Virtual Interface
 *
 * Copyright (c) 2013 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef included_l2bvi_h
#define included_l2bvi_h

#include <vlib/vlib.h>
#include <vnet/ethernet/ethernet.h>
#include <vppinfra/sparse_vec.h>

#include <vnet/l2/l2_input.h>

#define TO_BVI_ERR_OK        0
#define TO_BVI_ERR_TAGGED    1
#define TO_BVI_ERR_ETHERTYPE 2

// Send a packet from L2 processing to L3 via the BVI interface.
// Set next0 to the proper L3 input node.
// Return an error if the packet isn't what we expect.

static_always_inline u32 
l2_to_bvi (vlib_main_t * vlib_main,
           vnet_main_t * vnet_main,
           vlib_buffer_t * b0,
           u32 bvi_sw_if_index,
           next_by_ethertype_t * l3_next,
           u32 * next0)
{
  u8 l2_len;
  u16 ethertype;
  u8 * l3h;

  // Save L2 header position which may be changed due to packet replication
  vnet_buffer (b0)->ethernet.start_of_ethernet_header = b0->current_data;

  // Strip L2 header
  l2_len = vnet_buffer(b0)->l2.l2_len;
  vlib_buffer_advance (b0, l2_len);

  l3h = vlib_buffer_get_current (b0);
  ethertype = clib_net_to_host_u16(*(u16 *)(l3h - 2));

  // 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;

  // Go to appropriate L3 input node
  if (ethertype == ETHERNET_TYPE_IP4) {
    *next0 = l3_next->input_next_ip4;
  } else if (ethertype == ETHERNET_TYPE_IP6) {
    *next0 = l3_next->input_next_ip6;
  } else {
    // uncommon ethertype, check table
    u32 i0;

    i0 = sparse_vec_index (l3_next->input_next_by_type, ethertype);
    *next0 = vec_elt (l3_next->input_next_by_type, i0);

    if (i0 == SPARSE_VEC_INVALID_INDEX) {
      return TO_BVI_ERR_ETHERTYPE;
    } 
  }

  // increment BVI RX interface stat
  vlib_increment_combined_counter 
      (vnet_main->interface_main.combined_sw_if_counters
       + VNET_INTERFACE_COUNTER_RX,
       vlib_main->cpu_index, 
       vnet_buffer(b0)->sw_if_index[VLIB_RX],
       1,
       vlib_buffer_length_in_chain (vlib_main, b0));
  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,
                           u32 node_index);
#endif