node.c

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/*
 * Copyright (c) 2015 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.
 */
/*
 * ethernet_node.c: ethernet packet processing
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <vlib/vlib.h>
#include <vnet/pg/pg.h>
#include <vnet/ethernet/ethernet.h>
#include <vppinfra/sparse_vec.h>
#include <vnet/l2/l2_bvi.h>


#define foreach_ethernet_input_next             \
  _ (PUNT, "error-punt")                        \
  _ (DROP, "error-drop")                        \
  _ (LLC, "llc-input")                          

typedef enum {
#define _(s,n) ETHERNET_INPUT_NEXT_##s,
  foreach_ethernet_input_next
#undef _
  ETHERNET_INPUT_N_NEXT,
} ethernet_input_next_t;

typedef struct {
  u8 packet_data[32];
} ethernet_input_trace_t;

static u8 * format_ethernet_input_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  ethernet_input_trace_t * t = va_arg (*va, ethernet_input_trace_t *);

  s = format (s, "%U", format_ethernet_header, t->packet_data);

  return s;
}

vlib_node_registration_t ethernet_input_node;

typedef enum {
  ETHERNET_INPUT_VARIANT_ETHERNET,
  ETHERNET_INPUT_VARIANT_ETHERNET_TYPE,
  ETHERNET_INPUT_VARIANT_VLAN,
  ETHERNET_INPUT_VARIANT_NOT_L2,
} ethernet_input_variant_t;


// Parse the ethernet header to extract vlan tags and innermost ethertype
static_always_inline void
parse_header (ethernet_input_variant_t variant,
              vlib_buffer_t * b0,
              u16 * type, 
              u16 * orig_type, 
              u16 * outer_id,
              u16 * inner_id,
              u32 * match_flags) {
  u8 vlan_count;

  if (variant == ETHERNET_INPUT_VARIANT_ETHERNET 
      || variant == ETHERNET_INPUT_VARIANT_NOT_L2) {
    ethernet_header_t * e0;

    e0 = (void *) (b0->data + b0->current_data);

    vnet_buffer (b0)->ethernet.start_of_ethernet_header = b0->current_data;

    vlib_buffer_advance (b0, sizeof (e0[0]));

    *type = clib_net_to_host_u16(e0->type);
  } else if (variant == ETHERNET_INPUT_VARIANT_ETHERNET_TYPE) {
    // here when prior node was LLC/SNAP processing
    u16 * e0;

    e0 = (void *) (b0->data + b0->current_data);

    vlib_buffer_advance (b0, sizeof (e0[0]));

    *type = clib_net_to_host_u16(e0[0]);
  }

  // save for distinguishing between dot1q and dot1ad later
  *orig_type = *type;

  // default the tags to 0 (used if there is no corresponding tag)
  *outer_id = 0;
  *inner_id = 0;

  *match_flags = SUBINT_CONFIG_VALID | SUBINT_CONFIG_MATCH_0_TAG;
  vlan_count = 0;

  // check for vlan encaps
  if ((*type == ETHERNET_TYPE_VLAN) ||
      (*type == ETHERNET_TYPE_DOT1AD) ||
      (*type == ETHERNET_TYPE_VLAN_9100) ||
      (*type == ETHERNET_TYPE_VLAN_9200))
  {
    ethernet_vlan_header_t * h0;
    u16 tag;
 
    *match_flags = SUBINT_CONFIG_VALID | SUBINT_CONFIG_MATCH_1_TAG;

    h0 = (void *) (b0->data + b0->current_data);

    tag = clib_net_to_host_u16 (h0->priority_cfi_and_id);

    *outer_id = tag & 0xfff;

    *type = clib_net_to_host_u16(h0->type);

    vlib_buffer_advance (b0, sizeof (h0[0]));
    vlan_count = 1;

    if (*type == ETHERNET_TYPE_VLAN) {
      // Double tagged packet
      *match_flags = SUBINT_CONFIG_VALID | SUBINT_CONFIG_MATCH_2_TAG;

      h0 = (void *) (b0->data + b0->current_data);

      tag = clib_net_to_host_u16 (h0->priority_cfi_and_id);

      *inner_id = tag & 0xfff;

      *type = clib_net_to_host_u16(h0->type);

      vlib_buffer_advance (b0, sizeof (h0[0]));
      vlan_count = 2;

      if (*type == ETHERNET_TYPE_VLAN) {
        // More than double tagged packet
        *match_flags = SUBINT_CONFIG_VALID | SUBINT_CONFIG_MATCH_3_TAG;
        vlan_count = 3; // "unknown" number, aka, 3-or-more
      }
    }
  }
  ethernet_buffer_set_vlan_count(b0, vlan_count);
}

// Determine the subinterface for this packet, given the result of the
// vlan table lookups and vlan header parsing. Check the most specific
// matches first.
static_always_inline void
identify_subint (vnet_hw_interface_t * hi,
                 vlib_buffer_t * b0,
                 u32 match_flags, 
                 main_intf_t * main_intf, 
                 vlan_intf_t * vlan_intf, 
                 qinq_intf_t * qinq_intf, 
                 u32 * new_sw_if_index, 
                 u8 * error0, 
                 u32 * is_l2) 
{
  u32 matched;

  matched = eth_identify_subint (hi, b0, match_flags, 
                                 main_intf, vlan_intf, qinq_intf,
                                 new_sw_if_index, error0, is_l2);

  if (matched) {

    // Perform L3 my-mac filter
    // A unicast packet arriving on an L3 interface must have a dmac matching the interface mac.
    // This is required for promiscuous mode, else we will forward packets we aren't supposed to.
    if (!(*is_l2)) {
      ethernet_header_t * e0;
      e0 = (void *) (b0->data + vnet_buffer (b0)->ethernet.start_of_ethernet_header);

      if (!(ethernet_address_cast(e0->dst_address))) {
        if (!eth_mac_equal((u8 *)e0, hi->hw_address)) {
          *error0 = ETHERNET_ERROR_L3_MAC_MISMATCH;
        }
      }
    }

    // Check for down subinterface
    *error0 = (*new_sw_if_index) != ~0 ? (*error0) : ETHERNET_ERROR_DOWN;
  }
}

static_always_inline void
determine_next_node (ethernet_main_t * em,
                     ethernet_input_variant_t variant,
                     u32 is_l20, 
                     u32 type0, 
                     vlib_buffer_t * b0,
                     u8 * error0,
                     u8 * next0)
{
  if (PREDICT_FALSE (*error0 != ETHERNET_ERROR_NONE)) {
    // some error occurred
    *next0 = ETHERNET_INPUT_NEXT_DROP;
  } else if (is_l20) {
    *next0 = em->l2_next;
    // record the L2 len and reset the buffer so the L2 header is preserved
    vnet_buffer(b0)->l2.l2_len = b0->current_data;
    vlib_buffer_advance(b0, - ethernet_buffer_header_size(b0));

  // check for common IP/MPLS ethertypes
  } else if (type0 == ETHERNET_TYPE_IP4) {
    *next0 = em->l3_next.input_next_ip4;
  } else if (type0 == ETHERNET_TYPE_IP6) {
    *next0 = em->l3_next.input_next_ip6;
  } else if (type0 == ETHERNET_TYPE_MPLS_UNICAST) {
    *next0 = em->l3_next.input_next_mpls;

  } else if (em->redirect_l3) {
    // L3 Redirect is on, the cached common next nodes will be
    // pointing to the redirect node, catch the uncommon types here
    *next0 = em->redirect_l3_next;
  } else {
    // uncommon ethertype, check table
    u32 i0;
    i0 = sparse_vec_index (em->l3_next.input_next_by_type, type0);
    *next0 = vec_elt (em->l3_next.input_next_by_type, i0);
    *error0 = i0 == SPARSE_VEC_INVALID_INDEX ? ETHERNET_ERROR_UNKNOWN_TYPE : *error0;

    // The table is not populated with LLC values, so check that now.
    // If variant is variant_ethernet then we came from LLC processing. Don't 
    // go back there; drop instead using by keeping the drop/bad table result.
    if ((type0 < 0x600) && (variant == ETHERNET_INPUT_VARIANT_ETHERNET)) {
      *next0 = ETHERNET_INPUT_NEXT_LLC;
    }
  }
}

static_always_inline uword
ethernet_input_inline (vlib_main_t * vm,
                       vlib_node_runtime_t * node,
                       vlib_frame_t * from_frame,
                       ethernet_input_variant_t variant)
{
  vnet_main_t * vnm = vnet_get_main();
  ethernet_main_t * em = &ethernet_main;
  vlib_node_runtime_t * error_node;
  u32 n_left_from, next_index, * from, * to_next;
  u32 stats_sw_if_index, stats_n_packets, stats_n_bytes;
  u32 cpu_index = os_get_cpu_number();

  if (variant != ETHERNET_INPUT_VARIANT_ETHERNET)
    error_node = vlib_node_get_runtime (vm, ethernet_input_node.index);
  else
    error_node = node;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    vlib_trace_frame_buffers_only (vm, node,
                                   from,
                                   n_left_from,
                                   sizeof (from[0]),
                                   sizeof (ethernet_input_trace_t));

  next_index = node->cached_next_index;
  stats_sw_if_index = node->runtime_data[0];
  stats_n_packets = stats_n_bytes = 0;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          u32 bi0, bi1;
          vlib_buffer_t * b0, * b1;
          u8 next0, next1, error0, error1;
          u16 type0, orig_type0, type1, orig_type1;
          u16 outer_id0, inner_id0, outer_id1, inner_id1;
          u32 match_flags0, match_flags1;
          u32 old_sw_if_index0, new_sw_if_index0, len0, old_sw_if_index1, new_sw_if_index1, len1;
          vnet_hw_interface_t * hi0, * hi1;
          main_intf_t * main_intf0, * main_intf1;
          vlan_intf_t * vlan_intf0, * vlan_intf1;
          qinq_intf_t * qinq_intf0, * qinq_intf1;
          u32 is_l20, is_l21;

          /* Prefetch next iteration. */
          {
            vlib_buffer_t * b2, * b3;

            b2 = vlib_get_buffer (vm, from[2]);
            b3 = vlib_get_buffer (vm, from[3]);

            vlib_prefetch_buffer_header (b2, STORE);
            vlib_prefetch_buffer_header (b3, STORE);

            CLIB_PREFETCH (b2->data, sizeof (ethernet_header_t), LOAD);
            CLIB_PREFETCH (b3->data, sizeof (ethernet_header_t), LOAD);
          }

          bi0 = from[0];
          bi1 = from[1];
          to_next[0] = bi0;
          to_next[1] = bi1;
          from += 2;
          to_next += 2;
          n_left_to_next -= 2;
          n_left_from -= 2;

          b0 = vlib_get_buffer (vm, bi0);
          b1 = vlib_get_buffer (vm, bi1);

          error0 = error1 = ETHERNET_ERROR_NONE;

          parse_header (variant, 
                        b0,
                        &type0, 
                        &orig_type0, 
                        &outer_id0,
                        &inner_id0,
                        &match_flags0);

          parse_header (variant, 
                        b1,
                        &type1, 
                        &orig_type1, 
                        &outer_id1,
                        &inner_id1,
                        &match_flags1);

          old_sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
          old_sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];

          eth_vlan_table_lookups (em, 
                              vnm, 
                              old_sw_if_index0, 
                              orig_type0, 
                              outer_id0,
                              inner_id0,
                              &hi0,
                              &main_intf0,  
                              &vlan_intf0, 
                              &qinq_intf0);

          eth_vlan_table_lookups (em, 
                              vnm, 
                              old_sw_if_index1, 
                              orig_type1, 
                              outer_id1,
                              inner_id1,
                              &hi1,
                              &main_intf1,  
                              &vlan_intf1, 
                              &qinq_intf1);

          identify_subint (hi0,
                           b0,
                           match_flags0, 
                           main_intf0, 
                           vlan_intf0, 
                           qinq_intf0, 
                           &new_sw_if_index0, 
                           &error0, 
                           &is_l20);

          identify_subint (hi1,
                           b1,
                           match_flags1, 
                           main_intf1, 
                           vlan_intf1, 
                           qinq_intf1, 
                           &new_sw_if_index1, 
                           &error1, 
                           &is_l21);

          // Save RX sw_if_index for later nodes
          vnet_buffer (b0)->sw_if_index[VLIB_RX] = error0 != ETHERNET_ERROR_NONE ? old_sw_if_index0 : new_sw_if_index0;
          vnet_buffer (b1)->sw_if_index[VLIB_RX] = error1 != ETHERNET_ERROR_NONE ? old_sw_if_index1 : new_sw_if_index1;

          // Check if there is a stat to take (valid and non-main sw_if_index for pkt 0 or pkt 1)
          if (((new_sw_if_index0 != ~0) && (new_sw_if_index0 != old_sw_if_index0)) ||
              ((new_sw_if_index1 != ~0) && (new_sw_if_index1 != old_sw_if_index1))) {

            len0 = vlib_buffer_length_in_chain (vm, b0) + b0->current_data
                   - vnet_buffer (b0)->ethernet.start_of_ethernet_header;
            len1 = vlib_buffer_length_in_chain (vm, b1) + b1->current_data
                   - vnet_buffer (b1)->ethernet.start_of_ethernet_header;

            stats_n_packets += 2;
            stats_n_bytes += len0 + len1;

              if (PREDICT_FALSE (! (new_sw_if_index0 == stats_sw_if_index && new_sw_if_index1 == stats_sw_if_index)))
                {
                  stats_n_packets -= 2;
                  stats_n_bytes -= len0 + len1;

                  if (new_sw_if_index0 != old_sw_if_index0 && new_sw_if_index0 != ~0)
                    vlib_increment_combined_counter 
                        (vnm->interface_main.combined_sw_if_counters
                         + VNET_INTERFACE_COUNTER_RX,
                         cpu_index, 
                         new_sw_if_index0,
                         1,
                         len0);
                  if (new_sw_if_index1 != old_sw_if_index1 && new_sw_if_index1 != ~0)
                    vlib_increment_combined_counter 
                        (vnm->interface_main.combined_sw_if_counters
                         + VNET_INTERFACE_COUNTER_RX,
                         cpu_index, 
                         new_sw_if_index1,
                         1,
                         len1);

                  if (new_sw_if_index0 == new_sw_if_index1)
                    {
                      if (stats_n_packets > 0)
                        {
                          vlib_increment_combined_counter 
                              (vnm->interface_main.combined_sw_if_counters
                               + VNET_INTERFACE_COUNTER_RX,
                               cpu_index, 
                               stats_sw_if_index,
                               stats_n_packets,
                               stats_n_bytes);
                          stats_n_packets = stats_n_bytes = 0;
                        }
                      stats_sw_if_index = new_sw_if_index0;
                    }
                }
            }

          if (variant == ETHERNET_INPUT_VARIANT_NOT_L2)
              is_l20 = is_l21 = 0;

          determine_next_node(em, variant, is_l20, type0, b0, &error0, &next0);
          determine_next_node(em, variant, is_l21, type1, b1, &error1, &next1);
          
          b0->error = error_node->errors[error0];
          b1->error = error_node->errors[error1];

          // verify speculative enqueue
          vlib_validate_buffer_enqueue_x2(vm,node,next_index,to_next,n_left_to_next,bi0,bi1,next0,next1);
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t * b0;
          u8 error0, next0;
          u16 type0, orig_type0;
          u16 outer_id0, inner_id0;
          u32 match_flags0;
          u32 old_sw_if_index0, new_sw_if_index0, len0;
          vnet_hw_interface_t * hi0;
          main_intf_t * main_intf0;
          vlan_intf_t * vlan_intf0;
          qinq_intf_t * qinq_intf0;
          u32 is_l20;

          // Prefetch next iteration
          if (n_left_from > 1) {
            vlib_buffer_t * p2;
            
            p2 = vlib_get_buffer (vm, from[1]);
            vlib_prefetch_buffer_header (p2, STORE);
            CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
          }

          bi0 = from[0];
          to_next[0] = bi0;
          from += 1;
          to_next += 1;
          n_left_from -= 1;
          n_left_to_next -= 1;

          b0 = vlib_get_buffer (vm, bi0);

          error0 = ETHERNET_ERROR_NONE;

          parse_header (variant, 
                        b0,
                        &type0, 
                        &orig_type0, 
                        &outer_id0,
                        &inner_id0,
                        &match_flags0);

          old_sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];

          eth_vlan_table_lookups (em, 
                              vnm, 
                              old_sw_if_index0, 
                              orig_type0, 
                              outer_id0,
                              inner_id0,
                              &hi0,
                              &main_intf0,  
                              &vlan_intf0, 
                              &qinq_intf0);

          identify_subint (hi0,
                           b0,
                           match_flags0, 
                           main_intf0, 
                           vlan_intf0, 
                           qinq_intf0, 
                           &new_sw_if_index0, 
                           &error0, 
                           &is_l20);

          // Save RX sw_if_index for later nodes
          vnet_buffer (b0)->sw_if_index[VLIB_RX] = error0 != ETHERNET_ERROR_NONE ? old_sw_if_index0 : new_sw_if_index0;

          // Increment subinterface stats
          // Note that interface-level counters have already been incremented
          // prior to calling this function. Thus only subinterface counters
          // are incremented here.
          //
          // Interface level counters include packets received on the main 
          // interface and all subinterfaces. Subinterface level counters
          // include only those packets received on that subinterface
          // Increment stats if the subint is valid and it is not the main intf
          if ((new_sw_if_index0 != ~0) && (new_sw_if_index0 != old_sw_if_index0)) {

            len0 = vlib_buffer_length_in_chain (vm, b0) + b0->current_data
                - vnet_buffer (b0)->ethernet.start_of_ethernet_header;

            stats_n_packets += 1;
            stats_n_bytes += len0;

            // Batch stat increments from the same subinterface so counters
            // don't need to be incremented for every packet. 
            if (PREDICT_FALSE (new_sw_if_index0 != stats_sw_if_index)) {
              stats_n_packets -= 1;
              stats_n_bytes -= len0;

              if (new_sw_if_index0 != ~0)
                vlib_increment_combined_counter 
                    (vnm->interface_main.combined_sw_if_counters
                     + VNET_INTERFACE_COUNTER_RX,
                     cpu_index, 
                     new_sw_if_index0,
                     1,
                     len0);
              if (stats_n_packets > 0) {
                vlib_increment_combined_counter 
                    (vnm->interface_main.combined_sw_if_counters
                     + VNET_INTERFACE_COUNTER_RX,
                     cpu_index, 
                     stats_sw_if_index,
                     stats_n_packets,
                     stats_n_bytes);
                stats_n_packets = stats_n_bytes = 0;
              }
              stats_sw_if_index = new_sw_if_index0;
            }
          }

          if (variant == ETHERNET_INPUT_VARIANT_NOT_L2)
              is_l20 = 0;

          determine_next_node(em, variant, is_l20, type0, b0, &error0, &next0);

          b0->error = error_node->errors[error0];
          
          // verify speculative enqueue
          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           bi0, next0);
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

    // Increment any remaining batched stats
    if (stats_n_packets > 0)
    {
      vlib_increment_combined_counter 
          (vnm->interface_main.combined_sw_if_counters
           + VNET_INTERFACE_COUNTER_RX,
           cpu_index, 
           stats_sw_if_index,
           stats_n_packets,
           stats_n_bytes);
      node->runtime_data[0] = stats_sw_if_index;
    }

  return from_frame->n_vectors;
}

static uword
ethernet_input (vlib_main_t * vm,
                vlib_node_runtime_t * node,
                vlib_frame_t * from_frame)
{ return ethernet_input_inline (vm, node, from_frame, ETHERNET_INPUT_VARIANT_ETHERNET); }

static uword
ethernet_input_type (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * from_frame)
{ return ethernet_input_inline (vm, node, from_frame, ETHERNET_INPUT_VARIANT_ETHERNET_TYPE); }

static uword
ethernet_input_not_l2 (vlib_main_t * vm,
                       vlib_node_runtime_t * node,
                     vlib_frame_t * from_frame)
{ return ethernet_input_inline (vm, node, from_frame, ETHERNET_INPUT_VARIANT_NOT_L2); }


// Return the subinterface config struct for the given sw_if_index
// Also return via parameter the appropriate match flags for the
// configured number of tags.
// On error (unsupported or not ethernet) return 0.
static subint_config_t *
ethernet_sw_interface_get_config (vnet_main_t * vnm,
                                  u32 sw_if_index,
                                  u32 * flags,
                                  u32 * unsupported) {
  ethernet_main_t * em = &ethernet_main;
  vnet_hw_interface_t * hi;
  vnet_sw_interface_t * si;
  main_intf_t * main_intf;
  vlan_table_t * vlan_table;
  qinq_table_t * qinq_table;
  subint_config_t * subint = 0;
  
  hi = vnet_get_sup_hw_interface (vnm, sw_if_index);

  if (!hi || (hi->hw_class_index != ethernet_hw_interface_class.index)) {
    *unsupported = 0;
    goto done;  // non-ethernet interface
  }

  // ensure there's an entry for the main intf (shouldn't really be necessary)
  vec_validate (em->main_intfs, hi->hw_if_index);
  main_intf = vec_elt_at_index (em->main_intfs, hi->hw_if_index);

  // Locate the subint for the given ethernet config
  si = vnet_get_sw_interface (vnm, sw_if_index);

  if (si->sub.eth.flags.default_sub) {
    subint = &main_intf->default_subint;
    *flags = SUBINT_CONFIG_MATCH_0_TAG |
             SUBINT_CONFIG_MATCH_1_TAG |
             SUBINT_CONFIG_MATCH_2_TAG |
             SUBINT_CONFIG_MATCH_3_TAG;
  } else if ((si->sub.eth.flags.no_tags) ||
             (si->sub.eth.raw_flags == 0)) {
    // if no flags are set then this is a main interface
    // so treat as untagged
    subint = &main_intf->untagged_subint;
    *flags = SUBINT_CONFIG_MATCH_0_TAG;
  } else {
    // one or two tags
    // first get the vlan table
    if (si->sub.eth.flags.dot1ad) {
      if (main_intf->dot1ad_vlans == 0) {
        // Allocate a vlan table from the pool
        pool_get(em->vlan_pool, vlan_table); 
        main_intf->dot1ad_vlans = vlan_table - em->vlan_pool;
      } else {
        // Get ptr to existing vlan table
        vlan_table = vec_elt_at_index (em->vlan_pool, main_intf->dot1ad_vlans);
      }
    } else { // dot1q
      if (main_intf->dot1q_vlans == 0) {
        // Allocate a vlan table from the pool
        pool_get(em->vlan_pool, vlan_table); 
        main_intf->dot1q_vlans = vlan_table - em->vlan_pool;
      } else {
        // Get ptr to existing vlan table
        vlan_table = vec_elt_at_index (em->vlan_pool, main_intf->dot1q_vlans);
      }
    }

    if (si->sub.eth.flags.one_tag) {
      *flags = si->sub.eth.flags.exact_match ?
        SUBINT_CONFIG_MATCH_1_TAG :
        (SUBINT_CONFIG_MATCH_1_TAG |
         SUBINT_CONFIG_MATCH_2_TAG |
         SUBINT_CONFIG_MATCH_3_TAG);

      if (si->sub.eth.flags.outer_vlan_id_any) {
        // not implemented yet
        *unsupported =1;
        goto done;
      } else {
        // a single vlan, a common case
        subint = &vlan_table->vlans[si->sub.eth.outer_vlan_id].single_tag_subint;
      }

    } else {
      // Two tags
      *flags = si->sub.eth.flags.exact_match ?
        SUBINT_CONFIG_MATCH_2_TAG :
        (SUBINT_CONFIG_MATCH_2_TAG |
         SUBINT_CONFIG_MATCH_3_TAG);

      if (si->sub.eth.flags.outer_vlan_id_any && si->sub.eth.flags.inner_vlan_id_any) {
        // not implemented yet
        *unsupported = 1;
        goto done;
      }

      if (si->sub.eth.flags.inner_vlan_id_any) {
        // a specific outer and "any" inner
        // don't need a qinq table for this
        subint = &vlan_table->vlans[si->sub.eth.outer_vlan_id].inner_any_subint;
        if (si->sub.eth.flags.exact_match) {
          *flags = SUBINT_CONFIG_MATCH_2_TAG;
        } else {
          *flags = SUBINT_CONFIG_MATCH_2_TAG |
                   SUBINT_CONFIG_MATCH_3_TAG;
        }
      } else {
        // a specific outer + specifc innner vlan id, a common case

        // get the qinq table
        if (vlan_table->vlans[si->sub.eth.outer_vlan_id].qinqs == 0) {
          // Allocate a qinq table from the pool
          pool_get(em->qinq_pool, qinq_table); 
          vlan_table->vlans[si->sub.eth.outer_vlan_id].qinqs = qinq_table - em->qinq_pool;
        } else {
          // Get ptr to existing qinq table
          qinq_table = vec_elt_at_index (em->qinq_pool, vlan_table->vlans[si->sub.eth.outer_vlan_id].qinqs);
        }
        subint = &qinq_table->vlans[si->sub.eth.inner_vlan_id].subint;
      }
    }
  }

 done:
  return subint;
}

clib_error_t *
ethernet_sw_interface_up_down (vnet_main_t * vnm,
                               u32 sw_if_index,
                               u32 flags)
{
  subint_config_t * subint;
  u32 dummy_flags;
  u32 dummy_unsup;
  clib_error_t * error = 0;

  // Find the config for this subinterface
  subint = ethernet_sw_interface_get_config (vnm, sw_if_index, &dummy_flags, &dummy_unsup);

  if (subint == 0) {
    // not implemented yet or not ethernet
    goto done;
  }

  subint->sw_if_index =
    ((flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) ? sw_if_index : ~0);

 done:
  return error;
}

VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (ethernet_sw_interface_up_down);


// Set the L2/L3 mode for the subinterface
void
ethernet_sw_interface_set_l2_mode (vnet_main_t * vnm,
                                   u32 sw_if_index,
                                   u32 l2)
{
  subint_config_t *subint;
  u32 dummy_flags;
  u32 dummy_unsup;
  int is_port;
  vnet_sw_interface_t * sw = vnet_get_sw_interface (vnm, sw_if_index);

  is_port = !(sw->type == VNET_SW_INTERFACE_TYPE_SUB);

  // Find the config for this subinterface
  subint = ethernet_sw_interface_get_config (vnm, sw_if_index, &dummy_flags, &dummy_unsup);

  if (subint == 0) {
    // unimplemented or not ethernet
    goto done;
  }

  // Double check that the config we found is for our interface (or the interface is down)
  ASSERT ((subint->sw_if_index == sw_if_index) | (subint->sw_if_index == ~0));

  if (l2) {
    subint->flags |= SUBINT_CONFIG_L2;
    if (is_port) 
        subint->flags |= 
            SUBINT_CONFIG_MATCH_0_TAG | SUBINT_CONFIG_MATCH_1_TAG
            | SUBINT_CONFIG_MATCH_2_TAG | SUBINT_CONFIG_MATCH_3_TAG;
  } else {
    subint->flags &= ~SUBINT_CONFIG_L2;
    if (is_port) 
        subint->flags &= 
            ~(SUBINT_CONFIG_MATCH_1_TAG | SUBINT_CONFIG_MATCH_2_TAG
                    | SUBINT_CONFIG_MATCH_3_TAG);
  }

 done:
  return;
}

/*
 * Set the L2/L3 mode for the subinterface regardless of port
 */
void
ethernet_sw_interface_set_l2_mode_noport (vnet_main_t * vnm,
                                          u32 sw_if_index,
                                          u32 l2)
{
  subint_config_t *subint;
  u32 dummy_flags;
  u32 dummy_unsup;

  /* Find the config for this subinterface */
  subint = ethernet_sw_interface_get_config (vnm, sw_if_index, &dummy_flags, &dummy_unsup);

  if (subint == 0) {
    /* unimplemented or not ethernet */
    goto done;
  }

  /*
   * Double check that the config we found is for our interface (or the
   * interface is down)
   */
  ASSERT ((subint->sw_if_index == sw_if_index) | (subint->sw_if_index == ~0));

  if (l2) {
    subint->flags |= SUBINT_CONFIG_L2;
  } else {
    subint->flags &= ~SUBINT_CONFIG_L2;
  }

 done:
  return;
}

static clib_error_t *
ethernet_sw_interface_add_del (vnet_main_t * vnm,
                               u32 sw_if_index,
                               u32 is_create)
{
  clib_error_t * error = 0;
  subint_config_t *subint;
  u32 match_flags;
  u32 unsupported=0;

  // Find the config for this subinterface
  subint = ethernet_sw_interface_get_config (vnm, sw_if_index, &match_flags, &unsupported);

  if (subint == 0) {
    // not implemented yet or not ethernet
    if (unsupported) {
      // this is the NYI case 
      error = clib_error_return (0, "not implemented yet");
    }
    goto done;
  }

 if (!is_create) {
   subint->flags = 0;
   return error;
 }

  // Initialize the subint
  if (subint->flags & SUBINT_CONFIG_VALID) {
    // Error vlan already in use
    error = clib_error_return (0, "vlan is already in use");
  } else {
    // Note that config is L3 by defaulty
    subint->flags = SUBINT_CONFIG_VALID | match_flags;
    subint->sw_if_index = ~0;  // because interfaces are initially down
  }

 done:
  return error;
}

VNET_SW_INTERFACE_ADD_DEL_FUNCTION (ethernet_sw_interface_add_del);

static char * ethernet_error_strings[] = {
#define ethernet_error(n,c,s) s,
#include "error.def"
#undef ethernet_error
};

VLIB_REGISTER_NODE (ethernet_input_node) = {
  .function = ethernet_input,
  .name = "ethernet-input",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),

  .n_errors = ETHERNET_N_ERROR,
  .error_strings = ethernet_error_strings,

  .n_next_nodes = ETHERNET_INPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [ETHERNET_INPUT_NEXT_##s] = n,
    foreach_ethernet_input_next
#undef _
  },

  .format_buffer = format_ethernet_header_with_length,
  .format_trace = format_ethernet_input_trace,
  .unformat_buffer = unformat_ethernet_header,
};

VLIB_REGISTER_NODE (ethernet_input_type_node,static) = {
  .function = ethernet_input_type,
  .name = "ethernet-input-type",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),

  .n_next_nodes = ETHERNET_INPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [ETHERNET_INPUT_NEXT_##s] = n,
    foreach_ethernet_input_next
#undef _
  },
};

VLIB_REGISTER_NODE (ethernet_input_not_l2_node,static) = {
  .function = ethernet_input_not_l2,
  .name = "ethernet-input-not-l2",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),

  .n_next_nodes = ETHERNET_INPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [ETHERNET_INPUT_NEXT_##s] = n,
    foreach_ethernet_input_next
#undef _
  },
};

void ethernet_set_rx_redirect (vnet_main_t * vnm, 
                               vnet_hw_interface_t * hi, 
                               u32 enable)
{
  // Insure all packets go to ethernet-input (i.e. untagged ipv4 packets
  // don't go directly to ip4-input)
  vnet_hw_interface_rx_redirect_to_node 
      (vnm, hi->hw_if_index, enable ? ethernet_input_node.index : ~0);
}


/*
 * Initialization and registration for the next_by_ethernet structure
 */

clib_error_t * next_by_ethertype_init (next_by_ethertype_t * l3_next)
{
  l3_next->input_next_by_type = sparse_vec_new
    (/* elt bytes */ sizeof (l3_next->input_next_by_type[0]),
     /* bits in index */ BITS (((ethernet_header_t *) 0)->type));

  vec_validate (l3_next->sparse_index_by_input_next_index, ETHERNET_INPUT_NEXT_DROP);
  vec_validate (l3_next->sparse_index_by_input_next_index, ETHERNET_INPUT_NEXT_PUNT);
  l3_next->sparse_index_by_input_next_index[ETHERNET_INPUT_NEXT_DROP]
    = SPARSE_VEC_INVALID_INDEX;
  l3_next->sparse_index_by_input_next_index[ETHERNET_INPUT_NEXT_PUNT]
    = SPARSE_VEC_INVALID_INDEX;
 
  /* 
   * Make sure we don't wipe out an ethernet registration by mistake 
   * Can happen if init function ordering constraints are missing.
   */
  if (CLIB_DEBUG > 0)
    {
      ethernet_main_t * em = &ethernet_main;
      ASSERT(em->next_by_ethertype_register_called == 0);
    }

  return 0;
}

// Add an ethertype -> next index mapping to the structure
clib_error_t * next_by_ethertype_register (next_by_ethertype_t * l3_next,
                                           u32                   ethertype,
                                           u32                   next_index)
{
  u32 i;
  u16 * n;
  ethernet_main_t * em = &ethernet_main;

  if (CLIB_DEBUG > 0)
    {
      ethernet_main_t * em = &ethernet_main;
      em->next_by_ethertype_register_called = 1;
    }

  /* Setup ethernet type -> next index sparse vector mapping. */
  n = sparse_vec_validate (l3_next->input_next_by_type, ethertype);
  n[0] = next_index;

  /* Rebuild next index -> sparse index inverse mapping when sparse vector
     is updated. */
  vec_validate (l3_next->sparse_index_by_input_next_index, next_index);
  for (i = 1; i < vec_len (l3_next->input_next_by_type); i++)
    l3_next->sparse_index_by_input_next_index[l3_next->input_next_by_type[i]] = i;

  // do not allow the cached next index's to be updated if L3
  // redirect is enabled, as it will have overwritten them
  if (!em->redirect_l3) {
    // Cache common ethertypes directly
    if (ethertype == ETHERNET_TYPE_IP4) {
      l3_next->input_next_ip4 = next_index;
    } else if (ethertype == ETHERNET_TYPE_IP6) {
      l3_next->input_next_ip6 = next_index;
    } else if (ethertype == ETHERNET_TYPE_MPLS_UNICAST) {
      l3_next->input_next_mpls = next_index;
    }
  }
  return 0;
}


static clib_error_t * ethernet_input_init (vlib_main_t * vm)
{
  ethernet_main_t * em = &ethernet_main;
  __attribute__((unused)) vlan_table_t * invalid_vlan_table;
  __attribute__((unused)) qinq_table_t * invalid_qinq_table;

  ethernet_setup_node (vm, ethernet_input_node.index);
  ethernet_setup_node (vm, ethernet_input_type_node.index);
  ethernet_setup_node (vm, ethernet_input_not_l2_node.index);

  next_by_ethertype_init (&em->l3_next);
 
  // Initialize pools and vector for vlan parsing
  vec_validate (em->main_intfs, 10);  // 10 main interfaces
  pool_alloc(em->vlan_pool, 10);
  pool_alloc(em->qinq_pool, 1);

  // The first vlan pool will always be reserved for an invalid table
  pool_get(em->vlan_pool, invalid_vlan_table); // first id = 0
  // The first qinq pool will always be reserved for an invalid table
  pool_get(em->qinq_pool, invalid_qinq_table); // first id = 0

  return 0;
}

VLIB_INIT_FUNCTION (ethernet_input_init);

void
ethernet_register_input_type (vlib_main_t * vm,
                              ethernet_type_t type,
                              u32 node_index)
{
  ethernet_main_t * em = &ethernet_main;
  ethernet_type_info_t * ti;
  u32 i;

  {
    clib_error_t * error = vlib_call_init_function (vm, ethernet_init);
    if (error)
      clib_error_report (error);
  }

  ti = ethernet_get_type_info (em, type);
  ti->node_index = node_index;
  ti->next_index = vlib_node_add_next (vm, 
                                       ethernet_input_node.index,
                                       node_index);
  i = vlib_node_add_next (vm, 
                          ethernet_input_type_node.index,
                          node_index);
  ASSERT (i == ti->next_index);

  i = vlib_node_add_next (vm, 
                          ethernet_input_not_l2_node.index,
                          node_index);
  ASSERT (i == ti->next_index);

  // Add the L3 node for this ethertype to the next nodes structure
  next_by_ethertype_register (&em->l3_next, type, ti->next_index);

  // Call the registration functions for other nodes that want a mapping
  l2bvi_register_input_type (vm, type, node_index);
}

void
ethernet_register_l2_input (vlib_main_t * vm,
                            u32 node_index)
{
  ethernet_main_t * em = &ethernet_main;
  u32 i;

  em->l2_next = vlib_node_add_next (vm, ethernet_input_node.index, node_index);

  /* 
   * Even if we never use these arcs, we have to align the next indices...
   */
  i = vlib_node_add_next (vm, ethernet_input_type_node.index, node_index);

  ASSERT (i == em->l2_next);

  i = vlib_node_add_next (vm, 
                          ethernet_input_not_l2_node.index,
                          node_index);
  ASSERT (i == em->l2_next);
}

// Register a next node for L3 redirect, and enable L3 redirect
void
ethernet_register_l3_redirect (vlib_main_t * vm,
                               u32 node_index)
{
  ethernet_main_t * em = &ethernet_main;
  u32 i;

  em->redirect_l3 = 1;
  em->redirect_l3_next = vlib_node_add_next(vm,
                                            ethernet_input_node.index,
                                            node_index);
  /*
   * Change the cached next nodes to the redirect node
   */
  em->l3_next.input_next_ip4 = em->redirect_l3_next;
  em->l3_next.input_next_ip6 = em->redirect_l3_next;
  em->l3_next.input_next_mpls = em->redirect_l3_next;

  /*
   * Even if we never use these arcs, we have to align the next indices...
   */
  i = vlib_node_add_next (vm, ethernet_input_type_node.index, node_index);

  ASSERT (i == em->redirect_l3_next);
}