l2_input.c

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/*
 * l2_input.c : layer 2 input packet processing
 *
 * 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.
 */

#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/pg/pg.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ethernet/packet.h>
#include <vnet/ip/ip_packet.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/ip6_packet.h>
#include <vnet/fib/fib_node.h>
#include <vnet/ethernet/arp_packet.h>
#include <vlib/cli.h>
#include <vnet/l2/l2_input.h>
#include <vnet/l2/l2_output.h>
#include <vnet/l2/feat_bitmap.h>
#include <vnet/l2/l2_bvi.h>
#include <vnet/l2/l2_fib.h>
#include <vnet/l2/l2_bd.h>

#include <vppinfra/error.h>
#include <vppinfra/hash.h>
#include <vppinfra/cache.h>

/**
 * @file
 * @brief Interface Input Mode (Layer 2 Cross-Connect or Bridge / Layer 3).
 *
 * This file contains the CLI Commands that modify the input mode of an
 * interface. For interfaces in a Layer 2 cross-connect, all packets
 * received on one interface will be transmitted to the other. For
 * interfaces in a bridge-domain, packets will be forwarded to other
 * interfaces in the same bridge-domain based on destination mac address.
 * For interfaces in Layer 3 mode, the packets will be routed.
 */

/* Feature graph node names */
static char *l2input_feat_names[] = {
#define _(sym,name) name,
  foreach_l2input_feat
#undef _
};

char **
l2input_get_feat_names (void)
{
  return l2input_feat_names;
}

u8 *
format_l2_input_features (u8 * s, va_list * args)
{
  static char *display_names[] = {
#define _(sym,name) #sym,
    foreach_l2input_feat
#undef _
  };
  u32 feature_bitmap = va_arg (*args, u32);

  if (feature_bitmap == 0)
    {
      s = format (s, "  none configured");
      return s;
    }

  feature_bitmap &= ~L2INPUT_FEAT_DROP; /* Not a feature */
  int i;
  for (i = L2INPUT_N_FEAT; i >= 0; i--)
    if (feature_bitmap & (1 << i))
      s = format (s, "%10s (%s)\n", display_names[i], l2input_feat_names[i]);
  return s;
}

typedef struct
{
  /* per-pkt trace data */
  u8 src[6];
  u8 dst[6];
  u32 next_index;
  u32 sw_if_index;
} l2input_trace_t;

/* packet trace format function */
static u8 *
format_l2input_trace (u8 * s, va_list * args)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  l2input_trace_t *t = va_arg (*args, l2input_trace_t *);

  s = format (s, "l2-input: sw_if_index %d dst %U src %U",
              t->sw_if_index,
              format_ethernet_address, t->dst,
              format_ethernet_address, t->src);
  return s;
}

l2input_main_t l2input_main;

#define foreach_l2input_error                   \
_(L2INPUT,     "L2 input packets")              \
_(DROP,        "L2 input drops")

typedef enum
{
#define _(sym,str) L2INPUT_ERROR_##sym,
  foreach_l2input_error
#undef _
    L2INPUT_N_ERROR,
} l2input_error_t;

static char *l2input_error_strings[] = {
#define _(sym,string) string,
  foreach_l2input_error
#undef _
};

typedef enum
{                               /*  */
  L2INPUT_NEXT_LEARN,
  L2INPUT_NEXT_FWD,
  L2INPUT_NEXT_DROP,
  L2INPUT_N_NEXT,
} l2input_next_t;


static_always_inline void
classify_and_dispatch (l2input_main_t * msm, vlib_buffer_t * b0, u32 * next0)
{
  /*
   * Load L2 input feature struct
   * Load bridge domain struct
   * Parse ethernet header to determine unicast/mcast/broadcast
   * take L2 input stat
   * classify packet as IP/UDP/TCP, control, other
   * mask feature bitmap
   * go to first node in bitmap
   * Later: optimize VTM
   *
   * For L2XC,
   *   set tx sw-if-handle
   */

  u32 feat_mask = ~0;
  u32 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  ethernet_header_t *h0 = vlib_buffer_get_current (b0);

  /* Get config for the input interface */
  l2_input_config_t *config = vec_elt_at_index (msm->configs, sw_if_index0);

  /* Save split horizon group */
  vnet_buffer (b0)->l2.shg = config->shg;

  /* determine layer2 kind for stat and mask */
  if (PREDICT_FALSE (ethernet_address_cast (h0->dst_address)))
    {
      u8 *l3h0 = (u8 *) h0 + vnet_buffer (b0)->l2.l2_len;

#define get_u16(addr) ( *((u16 *)(addr)) )
      u16 ethertype = clib_net_to_host_u16 (get_u16 (l3h0 - 2));
      u8 protocol = ((ip6_header_t *) l3h0)->protocol;

      /* Disable bridge forwarding (flooding will execute instead if not xconnect) */
      feat_mask &= ~(L2INPUT_FEAT_FWD |
                     L2INPUT_FEAT_UU_FLOOD | L2INPUT_FEAT_GBP_FWD);

      /* Disable ARP-term for non-ARP and non-ICMP6 packet */
      if (ethertype != ETHERNET_TYPE_ARP &&
          (ethertype != ETHERNET_TYPE_IP6 || protocol != IP_PROTOCOL_ICMP6))
        feat_mask &= ~(L2INPUT_FEAT_ARP_TERM);

      /*
       * For packet from BVI - set SHG of ARP request or ICMPv6 neighbor
       * solicitation packet from BVI to 0 so it can also flood to VXLAN
       * tunnels or other ports with the same SHG as that of the BVI.
       */
      else if (PREDICT_FALSE (vnet_buffer (b0)->sw_if_index[VLIB_TX] ==
                              L2INPUT_BVI))
        {
          if (ethertype == ETHERNET_TYPE_ARP)
            {
              ethernet_arp_header_t *arp0 = (ethernet_arp_header_t *) l3h0;
              if (arp0->opcode ==
                  clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request))
                vnet_buffer (b0)->l2.shg = 0;
            }
          else                  /* must be ICMPv6 */
            {
              ip6_header_t *iph0 = (ip6_header_t *) l3h0;
              icmp6_neighbor_solicitation_or_advertisement_header_t *ndh0;
              ndh0 = ip6_next_header (iph0);
              if (ndh0->icmp.type == ICMP6_neighbor_solicitation)
                vnet_buffer (b0)->l2.shg = 0;
            }
        }
    }
  else
    {
      /*
       * For packet from BVI - set SHG of unicast packet from BVI to 0 so it
       * is not dropped on output to VXLAN tunnels or other ports with the
       * same SHG as that of the BVI.
       */
      if (PREDICT_FALSE (vnet_buffer (b0)->sw_if_index[VLIB_TX] ==
                         L2INPUT_BVI))
        vnet_buffer (b0)->l2.shg = 0;
    }


  if (config->bridge)
    {
      /* Do bridge-domain processing */
      u16 bd_index0 = config->bd_index;
      /* save BD ID for next feature graph nodes */
      vnet_buffer (b0)->l2.bd_index = bd_index0;

      /* Get config for the bridge domain interface */
      l2_bridge_domain_t *bd_config =
        vec_elt_at_index (msm->bd_configs, bd_index0);

      /* Save bridge domain and interface seq_num */
      /* *INDENT-OFF* */
      l2fib_seq_num_t sn = {
        .swif = *l2fib_swif_seq_num(sw_if_index0),
        .bd = bd_config->seq_num,
      };
      /* *INDENT-ON* */
      vnet_buffer (b0)->l2.l2fib_sn = sn.as_u16;;
      vnet_buffer (b0)->l2.bd_age = bd_config->mac_age;

      /*
       * Process bridge domain feature enables.
       * To perform learning/flooding/forwarding, the corresponding bit
       * must be enabled in both the input interface config and in the
       * bridge domain config. In the bd_bitmap, bits for features other
       * than learning/flooding/forwarding should always be set.
       */
      feat_mask = feat_mask & bd_config->feature_bitmap;
    }
  else if (config->xconnect)
    {
      /* Set the output interface */
      vnet_buffer (b0)->sw_if_index[VLIB_TX] = config->output_sw_if_index;
    }
  else
    feat_mask = L2INPUT_FEAT_DROP;

  /* mask out features from bitmap using packet type and bd config */
  u32 feature_bitmap = config->feature_bitmap & feat_mask;

  /* save for next feature graph nodes */
  vnet_buffer (b0)->l2.feature_bitmap = feature_bitmap;

  /* Determine the next node */
  *next0 = feat_bitmap_get_next_node_index (msm->feat_next_node_index,
                                            feature_bitmap);
}

static_always_inline uword
l2input_node_inline (vlib_main_t * vm,
                     vlib_node_runtime_t * node, vlib_frame_t * frame,
                     int do_trace)
{
  u32 n_left_from, *from, *to_next;
  l2input_next_t next_index;
  l2input_main_t *msm = &l2input_main;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;       /* number of packets to process */
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      /* get space to enqueue frame to graph node "next_index" */
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from >= 8 && n_left_to_next >= 4)
        {
          u32 bi0, bi1, bi2, bi3;
          vlib_buffer_t *b0, *b1, *b2, *b3;
          u32 next0, next1, next2, next3;
          u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;

          /* Prefetch next iteration. */
          {
            vlib_buffer_t *p4, *p5, *p6, *p7;

            p4 = vlib_get_buffer (vm, from[4]);
            p5 = vlib_get_buffer (vm, from[5]);
            p6 = vlib_get_buffer (vm, from[6]);
            p7 = vlib_get_buffer (vm, from[7]);

            /* Prefetch the buffer header and packet for the N+2 loop iteration */
            vlib_prefetch_buffer_header (p4, LOAD);
            vlib_prefetch_buffer_header (p5, LOAD);
            vlib_prefetch_buffer_header (p6, LOAD);
            vlib_prefetch_buffer_header (p7, LOAD);

            CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
            CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
            CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
            CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);

            /*
             * Don't bother prefetching the bridge-domain config (which
             * depends on the input config above). Only a small number of
             * bridge domains are expected. Plus the structure is small
             * and several fit in a cache line.
             */
          }

          /* speculatively enqueue b0 and b1 to the current next frame */
          /* bi is "buffer index", b is pointer to the buffer */
          to_next[0] = bi0 = from[0];
          to_next[1] = bi1 = from[1];
          to_next[2] = bi2 = from[2];
          to_next[3] = bi3 = from[3];
          from += 4;
          to_next += 4;
          n_left_from -= 4;
          n_left_to_next -= 4;

          b0 = vlib_get_buffer (vm, bi0);
          b1 = vlib_get_buffer (vm, bi1);
          b2 = vlib_get_buffer (vm, bi2);
          b3 = vlib_get_buffer (vm, bi3);

          if (do_trace)
            {
              /* RX interface handles */
              sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
              sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
              sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
              sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];

              if (b0->flags & VLIB_BUFFER_IS_TRACED)
                {
                  ethernet_header_t *h0 = vlib_buffer_get_current (b0);
                  l2input_trace_t *t =
                    vlib_add_trace (vm, node, b0, sizeof (*t));
                  t->sw_if_index = sw_if_index0;
                  clib_memcpy (t->src, h0->src_address, 6);
                  clib_memcpy (t->dst, h0->dst_address, 6);
                }
              if (b1->flags & VLIB_BUFFER_IS_TRACED)
                {
                  ethernet_header_t *h1 = vlib_buffer_get_current (b1);
                  l2input_trace_t *t =
                    vlib_add_trace (vm, node, b1, sizeof (*t));
                  t->sw_if_index = sw_if_index1;
                  clib_memcpy (t->src, h1->src_address, 6);
                  clib_memcpy (t->dst, h1->dst_address, 6);
                }
              if (b2->flags & VLIB_BUFFER_IS_TRACED)
                {
                  ethernet_header_t *h2 = vlib_buffer_get_current (b2);
                  l2input_trace_t *t =
                    vlib_add_trace (vm, node, b2, sizeof (*t));
                  t->sw_if_index = sw_if_index2;
                  clib_memcpy (t->src, h2->src_address, 6);
                  clib_memcpy (t->dst, h2->dst_address, 6);
                }
              if (b3->flags & VLIB_BUFFER_IS_TRACED)
                {
                  ethernet_header_t *h3 = vlib_buffer_get_current (b3);
                  l2input_trace_t *t =
                    vlib_add_trace (vm, node, b3, sizeof (*t));
                  t->sw_if_index = sw_if_index3;
                  clib_memcpy (t->src, h3->src_address, 6);
                  clib_memcpy (t->dst, h3->dst_address, 6);
                }
            }

          classify_and_dispatch (msm, b0, &next0);
          classify_and_dispatch (msm, b1, &next1);
          classify_and_dispatch (msm, b2, &next2);
          classify_and_dispatch (msm, b3, &next3);

          /* verify speculative enqueues, maybe switch current next frame */
          /* if next0==next1==next_index then nothing special needs to be done */
          vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           bi0, bi1, bi2, bi3,
                                           next0, next1, next2, next3);
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          u32 next0;
          u32 sw_if_index0;

          /* speculatively enqueue b0 to the current next frame */
          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);

          if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              ethernet_header_t *h0 = vlib_buffer_get_current (b0);
              l2input_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
              sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
              t->sw_if_index = sw_if_index0;
              clib_memcpy (t->src, h0->src_address, 6);
              clib_memcpy (t->dst, h0->dst_address, 6);
            }

          classify_and_dispatch (msm, b0, &next0);

          /* verify speculative enqueue, maybe switch current next frame */
          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);
    }

  vlib_node_increment_counter (vm, l2input_node.index,
                               L2INPUT_ERROR_L2INPUT, frame->n_vectors);

  return frame->n_vectors;
}

static uword
l2input_node_fn (vlib_main_t * vm,
                 vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
    return l2input_node_inline (vm, node, frame, 1 /* do_trace */ );
  return l2input_node_inline (vm, node, frame, 0 /* do_trace */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (l2input_node) = {
  .function = l2input_node_fn,
  .name = "l2-input",
  .vector_size = sizeof (u32),
  .format_trace = format_l2input_trace,
  .format_buffer = format_ethernet_header_with_length,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(l2input_error_strings),
  .error_strings = l2input_error_strings,

  .n_next_nodes = L2INPUT_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
       [L2INPUT_NEXT_LEARN] = "l2-learn",
       [L2INPUT_NEXT_FWD]   = "l2-fwd",
       [L2INPUT_NEXT_DROP]  = "error-drop",
  },
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (l2input_node, l2input_node_fn)
     clib_error_t *l2input_init (vlib_main_t * vm)
{
  l2input_main_t *mp = &l2input_main;

  mp->vlib_main = vm;
  mp->vnet_main = vnet_get_main ();

  /* Get packets RX'd from L2 interfaces */
  ethernet_register_l2_input (vm, l2input_node.index);

  /* Create the config vector */
  vec_validate (mp->configs, 100);
  /* create 100 sw interface entries and zero them */

  /* Initialize the feature next-node indexes */
  feat_bitmap_init_next_nodes (vm,
                               l2input_node.index,
                               L2INPUT_N_FEAT,
                               l2input_get_feat_names (),
                               mp->feat_next_node_index);

  return 0;
}

VLIB_INIT_FUNCTION (l2input_init);


/** Get a pointer to the config for the given interface. */
l2_input_config_t *
l2input_intf_config (u32 sw_if_index)
{
  l2input_main_t *mp = &l2input_main;

  vec_validate (mp->configs, sw_if_index);
  return vec_elt_at_index (mp->configs, sw_if_index);
}

/** Enable (or disable) the feature in the bitmap for the given interface. */
u32
l2input_intf_bitmap_enable (u32 sw_if_index, u32 feature_bitmap, u32 enable)
{
  l2_input_config_t *config = l2input_intf_config (sw_if_index);

  if (enable)
    config->feature_bitmap |= feature_bitmap;
  else
    config->feature_bitmap &= ~feature_bitmap;

  return config->feature_bitmap;
}

u32
l2input_set_bridge_features (u32 bd_index, u32 feat_mask, u32 feat_value)
{
  l2_bridge_domain_t *bd_config = l2input_bd_config (bd_index);;
  bd_validate (bd_config);
  bd_config->feature_bitmap =
    (bd_config->feature_bitmap & ~feat_mask) | feat_value;
  return bd_config->feature_bitmap;
}

void
l2input_interface_mac_change (u32 sw_if_index,
                              const u8 * old_address, const u8 * new_address)
{
  /* check if the sw_if_index passed is a BVI in a BD */
  l2_input_config_t *intf_config;

  intf_config = l2input_intf_config (sw_if_index);

  if (intf_config->bridge && intf_config->bvi)
    {
      /* delete and re-add l2fib entry for the bvi interface */
      l2fib_del_entry (old_address, intf_config->bd_index, sw_if_index);
      l2fib_add_entry (new_address,
                       intf_config->bd_index,
                       sw_if_index,
                       L2FIB_ENTRY_RESULT_FLAG_BVI |
                       L2FIB_ENTRY_RESULT_FLAG_STATIC);
    }
}

/**
 * Set the subinterface to run in l2 or l3 mode.
 * For L3 mode, just the sw_if_index is specified.
 * For bridged mode, the bd id and bvi flag are also specified.
 * For xconnect mode, the peer sw_if_index is also specified.
 * Return 0 if ok, or non-0 if there was an error.
 */

u32
set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,     /*           */
                 u32 mode,      /* One of L2 modes or back to L3 mode        */
                 u32 sw_if_index,       /* sw interface index                */
                 u32 bd_index,  /* for bridged interface                     */
                 l2_bd_port_type_t port_type,   /* port_type */
                 u32 shg,       /* the bridged interface split horizon group */
                 u32 xc_sw_if_index)    /* peer interface for xconnect       */
{
  l2input_main_t *mp = &l2input_main;
  l2output_main_t *l2om = &l2output_main;
  vnet_main_t *vnm = vnet_get_main ();
  vnet_hw_interface_t *hi;
  l2_output_config_t *out_config;
  l2_input_config_t *config;
  l2_bridge_domain_t *bd_config;
  i32 l2_if_adjust = 0;
  vnet_device_class_t *dev_class;

  hi = vnet_get_sup_hw_interface (vnet_main, sw_if_index);
  config = l2input_intf_config (sw_if_index);

  if (config->bridge)
    {
      /* Interface is already in bridge mode. Undo the existing config. */
      bd_config = vec_elt_at_index (mp->bd_configs, config->bd_index);

      /* remove interface from flood vector */
      bd_remove_member (bd_config, sw_if_index);

      /* undo any BVI-related config */
      if (bd_config->bvi_sw_if_index == sw_if_index)
        {
          vnet_sw_interface_t *si;

          bd_config->bvi_sw_if_index = ~0;
          config->bvi = 0;

          /* delete the l2fib entry for the bvi interface */
          l2fib_del_entry (hi->hw_address, config->bd_index, sw_if_index);

          /* since this is a no longer BVI interface do not to flood to it */
          si = vnet_get_sw_interface (vnm, sw_if_index);
          si->flood_class = VNET_FLOOD_CLASS_NO_FLOOD;
        }
      if (bd_config->uu_fwd_sw_if_index == sw_if_index)
        {
          bd_config->uu_fwd_sw_if_index = ~0;
          bd_config->feature_bitmap &= ~L2INPUT_FEAT_UU_FWD;
        }

      /* Clear MACs learned on the interface */
      if ((config->feature_bitmap & L2INPUT_FEAT_LEARN) ||
          (bd_config->feature_bitmap & L2INPUT_FEAT_LEARN))
        l2fib_flush_int_mac (vm, sw_if_index);

      l2_if_adjust--;
    }
  else if (config->xconnect)
    {
      l2_if_adjust--;
    }

  /* Make sure vector is big enough */
  vec_validate_init_empty (l2om->output_node_index_vec, sw_if_index,
                           L2OUTPUT_NEXT_DROP);

  /* Initialize the l2-input configuration for the interface */
  if (mode == MODE_L3)
    {
      /* Set L2 config to BD index 0 so that if any packet accidentally
       * came in on L2 path, it will be dropped in BD 0 */
      config->xconnect = 0;
      config->bridge = 0;
      config->shg = 0;
      config->bd_index = 0;
      config->feature_bitmap = L2INPUT_FEAT_DROP;

      /* Clear L2 output config */
      out_config = l2output_intf_config (sw_if_index);
      memset (out_config, 0, sizeof (l2_output_config_t));

      /* Make sure any L2-output packet to this interface now in L3 mode is
       * dropped. This may happen if L2 FIB MAC entry is stale */
      l2om->output_node_index_vec[sw_if_index] = L2OUTPUT_NEXT_BAD_INTF;
    }
  else
    {
      /* Add or update l2-output node next-arc and output_node_index_vec table
       * for the interface */
      l2output_create_output_node_mapping (vm, vnet_main, sw_if_index);

      if (mode == MODE_L2_BRIDGE)
        {
          u8 member_flags;

          /*
           * Remove a check that the interface must be an Ethernet.
           * Specifically so we can bridge to L3 tunnel interfaces.
           * Here's the check:
           * if (hi->hw_class_index != ethernet_hw_interface_class.index)
           *
           */
          if (!hi)
            return MODE_ERROR_ETH;      /* non-ethernet */

          config->xconnect = 0;
          config->bridge = 1;
          config->bd_index = bd_index;
          *l2fib_valid_swif_seq_num (sw_if_index) += 1;

          /*
           * Enable forwarding, flooding, learning and ARP termination by default
           * (note that ARP term is disabled on BD feature bitmap by default)
           */
          config->feature_bitmap |= (L2INPUT_FEAT_FWD |
                                     L2INPUT_FEAT_UU_FLOOD |
                                     L2INPUT_FEAT_UU_FWD |
                                     L2INPUT_FEAT_FLOOD |
                                     L2INPUT_FEAT_LEARN |
                                     L2INPUT_FEAT_ARP_TERM);

          /* Make sure last-chance drop is configured */
          config->feature_bitmap |= L2INPUT_FEAT_DROP;

          /* Make sure xconnect is disabled */
          config->feature_bitmap &= ~L2INPUT_FEAT_XCONNECT;

          /* Set up bridge domain */
          bd_config = l2input_bd_config (bd_index);
          bd_validate (bd_config);

          /* TODO: think: add l2fib entry even for non-bvi interface? */

          /* Do BVI interface initializations */
          if (L2_BD_PORT_TYPE_BVI == port_type)
            {
              vnet_sw_interface_t *si;

              /* ensure BD has no bvi interface (or replace that one with this??) */
              if (bd_config->bvi_sw_if_index != ~0)
                {
                  return MODE_ERROR_BVI_DEF;    /* bd already has a bvi interface */
                }
              bd_config->bvi_sw_if_index = sw_if_index;
              config->bvi = 1;

              /* create the l2fib entry for the bvi interface */
              l2fib_add_entry (hi->hw_address, bd_index, sw_if_index,
                               L2FIB_ENTRY_RESULT_FLAG_BVI |
                               L2FIB_ENTRY_RESULT_FLAG_STATIC);

              /* Disable learning by default. no use since l2fib entry is static. */
              config->feature_bitmap &= ~L2INPUT_FEAT_LEARN;

              /* since this is a BVI interface we want to flood to it */
              si = vnet_get_sw_interface (vnm, sw_if_index);
              si->flood_class = VNET_FLOOD_CLASS_BVI;
              member_flags = L2_FLOOD_MEMBER_BVI;
            }
          else if (L2_BD_PORT_TYPE_UU_FWD == port_type)
            {
              bd_config->uu_fwd_sw_if_index = sw_if_index;
              bd_config->feature_bitmap |= L2INPUT_FEAT_UU_FWD;
            }
          else
            {
              member_flags = L2_FLOOD_MEMBER_NORMAL;
            }

          if (L2_BD_PORT_TYPE_NORMAL == port_type ||
              L2_BD_PORT_TYPE_BVI == port_type)
            {
              /* Add interface to bridge-domain flood vector */
              l2_flood_member_t member = {
                .sw_if_index = sw_if_index,
                .flags = member_flags,
                .shg = shg,
              };
              bd_add_member (bd_config, &member);
            }
        }
      else if (mode == MODE_L2_XC)
        {
          config->xconnect = 1;
          config->bridge = 0;
          config->output_sw_if_index = xc_sw_if_index;

          /* Make sure last-chance drop is configured */
          config->feature_bitmap |= L2INPUT_FEAT_DROP;

          /* Make sure bridging features are disabled */
          config->feature_bitmap &=
            ~(L2INPUT_FEAT_LEARN | L2INPUT_FEAT_FWD | L2INPUT_FEAT_FLOOD);

          config->feature_bitmap |= L2INPUT_FEAT_XCONNECT;
          shg = 0;              /* not used in xconnect */
        }
      else if (mode == MODE_L2_CLASSIFY)
        {
          config->xconnect = 1;
          config->bridge = 0;
          config->output_sw_if_index = xc_sw_if_index;

          /* Make sure last-chance drop is configured */
          config->feature_bitmap |=
            L2INPUT_FEAT_DROP | L2INPUT_FEAT_INPUT_CLASSIFY;

          /* Make sure bridging features are disabled */
          config->feature_bitmap &=
            ~(L2INPUT_FEAT_LEARN | L2INPUT_FEAT_FWD | L2INPUT_FEAT_FLOOD);
          shg = 0;              /* not used in xconnect */

          /* Insure all packets go to ethernet-input */
          ethernet_set_rx_redirect (vnet_main, hi, 1);
        }

      /* set up split-horizon group and set output feature bit */
      config->shg = shg;
      out_config = l2output_intf_config (sw_if_index);
      out_config->shg = shg;
      out_config->feature_bitmap |= L2OUTPUT_FEAT_OUTPUT;

      /*
       * Test: remove this when non-IP features can be configured.
       * Enable a non-IP feature to test IP feature masking
       * config->feature_bitmap |= L2INPUT_FEAT_CTRL_PKT;
       */

      l2_if_adjust++;
    }

  /* Adjust count of L2 interfaces */
  hi->l2_if_count += l2_if_adjust;

  if (hi->hw_class_index == ethernet_hw_interface_class.index)
    {
      if ((hi->l2_if_count == 1) && (l2_if_adjust == 1))
        {
          /* Just added first L2 interface on this port */

          /* Set promiscuous mode on the l2 interface */
          ethernet_set_flags (vnet_main, hi->hw_if_index,
                              ETHERNET_INTERFACE_FLAG_ACCEPT_ALL);

          /* ensure all packets go to ethernet-input */
          ethernet_set_rx_redirect (vnet_main, hi, 1);

        }
      else if ((hi->l2_if_count == 0) && (l2_if_adjust == -1))
        {
          /* Just removed only L2 subinterface on this port */

          /* Disable promiscuous mode on the l2 interface */
          ethernet_set_flags (vnet_main, hi->hw_if_index, 0);

          /* Allow ip packets to go directly to ip4-input etc */
          ethernet_set_rx_redirect (vnet_main, hi, 0);
        }
    }

  /* Set up the L2/L3 flag in the interface parsing tables */
  ethernet_sw_interface_set_l2_mode (vnm, sw_if_index, (mode != MODE_L3));

  dev_class = vnet_get_device_class (vnet_main, hi->dev_class_index);
  if (dev_class->set_l2_mode_function)
    {
      dev_class->set_l2_mode_function (vnet_main, hi, l2_if_adjust);
    }

  return 0;
}

/**
 * Set subinterface in bridging mode with a bridge-domain ID.
 * The CLI format is:
 *   set interface l2 bridge <interface> <bd> [bvi] [split-horizon-group]
 */
static clib_error_t *
int_l2_bridge (vlib_main_t * vm,
               unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  l2_bd_port_type_t port_type;
  clib_error_t *error = 0;
  u32 bd_index, bd_id;
  u32 sw_if_index;
  u32 rc;
  u32 shg;

  if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
    {
      error = clib_error_return (0, "unknown interface `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  if (!unformat (input, "%d", &bd_id))
    {
      error = clib_error_return (0, "expected bridge domain ID `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  if (bd_id > L2_BD_ID_MAX)
    {
      error = clib_error_return (0, "bridge domain ID exceed 16M limit",
                                 format_unformat_error, input);
      goto done;
    }
  bd_index = bd_find_or_add_bd_index (&bd_main, bd_id);

  /* optional bvi  */
  port_type = L2_BD_PORT_TYPE_NORMAL;
  if (unformat (input, "bvi"))
    port_type = L2_BD_PORT_TYPE_BVI;
  if (unformat (input, "uu-fwd"))
    port_type = L2_BD_PORT_TYPE_UU_FWD;

  /* optional split horizon group */
  shg = 0;
  (void) unformat (input, "%d", &shg);

  /* set the interface mode */
  if ((rc =
       set_int_l2_mode (vm, vnm, MODE_L2_BRIDGE, sw_if_index, bd_index,
                        port_type, shg, 0)))
    {
      if (rc == MODE_ERROR_ETH)
        {
          error = clib_error_return (0, "bridged interface must be ethernet",
                                     format_unformat_error, input);
        }
      else if (rc == MODE_ERROR_BVI_DEF)
        {
          error =
            clib_error_return (0, "bridge-domain already has a bvi interface",
                               format_unformat_error, input);
        }
      else
        {
          error = clib_error_return (0, "invalid configuration for interface",
                                     format_unformat_error, input);
        }
      goto done;
    }

done:
  return error;
}

/*?
 * Use this command put an interface into Layer 2 bridge domain. If a
 * bridge-domain with the provided bridge-domain-id does not exist, it
 * will be created. Interfaces in a bridge-domain forward packets to
 * other interfaces in the same bridge-domain based on destination mac
 * address. To remove an interface from a the Layer 2 bridge domain,
 * put the interface in a different mode, for example Layer 3 mode.
 *
 * Optionally, an interface can be added to a Layer 2 bridge-domain as
 * a Bridged Virtual Interface (bvi). Only one interface in a Layer 2
 * bridge-domain can be a bvi.
 *
 * Optionally, a split-horizon group can also be specified. This defaults
 * to 0 if not specified.
 *
 * @cliexpar
 * Example of how to configure a Layer 2 bridge-domain with three
 * interfaces (where 200 is the bridge-domain-id):
 * @cliexcmd{set interface l2 bridge GigabitEthernet0/8/0.200 200}
 * This interface is added a BVI interface:
 * @cliexcmd{set interface l2 bridge GigabitEthernet0/9/0.200 200 bvi}
 * This interface also has a split-horizon group of 1 specified:
 * @cliexcmd{set interface l2 bridge GigabitEthernet0/a/0.200 200 1}
 * Example of how to remove an interface from a Layer2 bridge-domain:
 * @cliexcmd{set interface l3 GigabitEthernet0/a/0.200}
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (int_l2_bridge_cli, static) = {
  .path = "set interface l2 bridge",
  .short_help = "set interface l2 bridge <interface> <bridge-domain-id> [bvi|uu-fwd] [shg]",
  .function = int_l2_bridge,
};
/* *INDENT-ON* */

/**
 * Set subinterface in xconnect mode with another interface.
 * The CLI format is:
 *   set interface l2 xconnect <interface> <peer interface>
 */
static clib_error_t *
int_l2_xc (vlib_main_t * vm,
           unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  clib_error_t *error = 0;
  u32 sw_if_index;
  u32 xc_sw_if_index;

  if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
    {
      error = clib_error_return (0, "unknown interface `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  if (!unformat_user
      (input, unformat_vnet_sw_interface, vnm, &xc_sw_if_index))
    {
      error = clib_error_return (0, "unknown peer interface `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  /* set the interface mode */
  if (set_int_l2_mode
      (vm, vnm, MODE_L2_XC, sw_if_index, 0, L2_BD_PORT_TYPE_NORMAL,
       0, xc_sw_if_index))
    {
      error = clib_error_return (0, "invalid configuration for interface",
                                 format_unformat_error, input);
      goto done;
    }

done:
  return error;
}

/*?
 * Use this command put an interface into Layer 2 cross-connect mode.
 * Both interfaces must be in this mode for bi-directional traffic. All
 * packets received on one interface will be transmitted to the other.
 * To remove the Layer 2 cross-connect, put the interface in a different
 * mode, for example Layer 3 mode.
 *
 * @cliexpar
 * Example of how to configure a Layer2 cross-connect between two interfaces:
 * @cliexcmd{set interface l2 xconnect GigabitEthernet0/8/0.300 GigabitEthernet0/9/0.300}
 * @cliexcmd{set interface l2 xconnect GigabitEthernet0/9/0.300 GigabitEthernet0/8/0.300}
 * Example of how to remove a Layer2 cross-connect:
 * @cliexcmd{set interface l3 GigabitEthernet0/8/0.300}
 * @cliexcmd{set interface l3 GigabitEthernet0/9/0.300}
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (int_l2_xc_cli, static) = {
  .path = "set interface l2 xconnect",
  .short_help = "set interface l2 xconnect <interface> <peer interface>",
  .function = int_l2_xc,
};
/* *INDENT-ON* */

/**
 * Set subinterface in L3 mode.
 * The CLI format is:
 *   set interface l3 <interface>
 */
static clib_error_t *
int_l3 (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  clib_error_t *error = 0;
  u32 sw_if_index;

  if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
    {
      error = clib_error_return (0, "unknown interface `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  /* set the interface mode */
  if (set_int_l2_mode (vm, vnm, MODE_L3, sw_if_index, 0,
                       L2_BD_PORT_TYPE_NORMAL, 0, 0))
    {
      error = clib_error_return (0, "invalid configuration for interface",
                                 format_unformat_error, input);
      goto done;
    }

done:
  return error;
}

/*?
 * Modify the packet processing mode of the interface to Layer 3, which
 * implies packets will be routed. This is the default mode of an interface.
 * Use this command to remove an interface from a Layer 2 cross-connect or a
 * Layer 2 bridge.
 *
 * @cliexpar
 * Example of how to set the mode of an interface to Layer 3:
 * @cliexcmd{set interface l3 GigabitEthernet0/8/0.200}
?*/
/* *INDENT-OFF* */
     VLIB_CLI_COMMAND (int_l3_cli, static) = {
  .path = "set interface l3",
  .short_help = "set interface l3 <interface>",
  .function = int_l3,
};
/* *INDENT-ON* */

/**
 * Show interface mode.
 * The CLI format is:
 *    show mode [<if-name1> <if-name2> ...]
 */
static clib_error_t *
show_int_mode (vlib_main_t * vm,
               unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  clib_error_t *error = 0;
  char *mode;
  u8 *args;
  vnet_interface_main_t *im = &vnm->interface_main;

  vnet_sw_interface_t *si, *sis = 0;
  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      u32 sw_if_index;

      /* See if user wants to show specific interface */
      if (unformat
          (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index))
        {
          si = pool_elt_at_index (im->sw_interfaces, sw_if_index);
          vec_add1 (sis, si[0]);
        }
      else
        {
          error = clib_error_return (0, "unknown input `%U'",
                                     format_unformat_error, input);
          goto done;
        }
    }

  if (vec_len (sis) == 0)       /* Get all interfaces */
    {
      /* Gather interfaces. */
      sis = vec_new (vnet_sw_interface_t, pool_elts (im->sw_interfaces));
      _vec_len (sis) = 0;
      /* *INDENT-OFF* */
      pool_foreach (si, im->sw_interfaces, ({ vec_add1 (sis, si[0]); }));
      /* *INDENT-ON* */
    }

  vec_foreach (si, sis)
  {
    l2_input_config_t *config = l2input_intf_config (si->sw_if_index);
    if (config->bridge)
      {
        u32 bd_id;
        mode = "l2 bridge";
        bd_id = l2input_main.bd_configs[config->bd_index].bd_id;

        args = format (0, "bd_id %d%s%d", bd_id,
                       config->bvi ? " bvi shg " : " shg ", config->shg);
      }
    else if (config->xconnect)
      {
        mode = "l2 xconnect";
        args = format (0, "%U",
                       format_vnet_sw_if_index_name,
                       vnm, config->output_sw_if_index);
      }
    else
      {
        mode = "l3";
        args = format (0, " ");
      }
    vlib_cli_output (vm, "%s %U %v\n",
                     mode,
                     format_vnet_sw_if_index_name,
                     vnm, si->sw_if_index, args);
    vec_free (args);
  }

done:
  vec_free (sis);

  return error;
}

/*?
 * Show the packet processing mode (Layer2 cross-connect, Layer 2 bridge,
 * Layer 3 routed) of all interfaces and sub-interfaces, or limit the
 * output to just the provided list of interfaces and sub-interfaces.
 * The output shows the mode, the interface, and if the interface is
 * a member of a bridge, the bridge-domain-id and the split horizon group (shg).
 *
 * @cliexpar
 * Example of displaying the mode of all interfaces:
 * @cliexstart{show mode}
 * l3 local0
 * l3 GigabitEthernet0/8/0
 * l3 GigabitEthernet0/9/0
 * l3 GigabitEthernet0/a/0
 * l2 bridge GigabitEthernet0/8/0.200 bd_id 200 shg 0
 * l2 bridge GigabitEthernet0/9/0.200 bd_id 200 shg 0
 * l2 bridge GigabitEthernet0/a/0.200 bd_id 200 shg 0
 * l2 xconnect GigabitEthernet0/8/0.300 GigabitEthernet0/9/0.300
 * l2 xconnect GigabitEthernet0/9/0.300 GigabitEthernet0/8/0.300
 * @cliexend
 * Example of displaying the mode of a selected list of interfaces:
 * @cliexstart{show mode GigabitEthernet0/8/0 GigabitEthernet0/8/0.200}
 * l3 GigabitEthernet0/8/0
 * l2 bridge GigabitEthernet0/8/0.200 bd_id 200 shg 0
 * @cliexend
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_l2_mode, static) = {
  .path = "show mode",
  .short_help = "show mode [<if-name1> <if-name2> ...]",
  .function = show_int_mode,
};
/* *INDENT-ON* */

#define foreach_l2_init_function                \
_(feat_bitmap_drop_init)                        \
_(l2fib_init)                                   \
_(l2_input_classify_init)                             \
_(l2bd_init)                                    \
_(l2fwd_init)                                   \
_(l2_in_out_acl_init)                           \
_(l2input_init)                                 \
_(l2_vtr_init)                                  \
_(l2_invtr_init)                                \
_(l2_efp_filter_init)                           \
_(l2learn_init)                                 \
_(l2flood_init)                                 \
_(l2output_init)                                \
_(l2_patch_init)                                \
_(l2_xcrw_init)

clib_error_t *
l2_init (vlib_main_t * vm)
{
  clib_error_t *error;

#define _(a) do {                                                       \
  if ((error = vlib_call_init_function (vm, a))) return error; }        \
while (0);
  foreach_l2_init_function;
#undef _
  return 0;
}

VLIB_INIT_FUNCTION (l2_init);

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */