src/vnet/l2/l2_flood.c - fdio/vpp - Gitiles

 /*
  * l2_flood.c : layer 2 flooding
  *
  * 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 <vlib/cli.h>
 #include <vnet/l2/l2_input.h>
 #include <vnet/l2/feat_bitmap.h>
 #include <vnet/l2/l2_bvi.h>
 #include <vnet/replication.h>
 #include <vnet/l2/l2_fib.h>

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


 /**
  * @file
  * @brief Ethernet Flooding.
  *
  * Flooding uses the packet replication infrastructure to send a copy of the
  * packet to each member interface. Logically the replication infrastructure
  * expects two graph nodes: a prep node that initiates replication and sends the
  * packet to the first destination, and a recycle node that is passed the packet
  * after it has been transmitted.
  *
  * To decrease the amount of code, l2 flooding implements both functions in
  * the same graph node. This node can tell if is it being called as the "prep"
  * or "recycle" using replication_is_recycled().
  */


 typedef struct
 {

   /* Next nodes for each feature */
   u32 feat_next_node_index[32];

   /* next node index for the L3 input node of each ethertype */
   next_by_ethertype_t l3_next;

   /* convenience variables */
   vlib_main_t *vlib_main;
   vnet_main_t *vnet_main;
 } l2flood_main_t;

 typedef struct
 {
   u8 src[6];
   u8 dst[6];
   u32 sw_if_index;
   u16 bd_index;
 } l2flood_trace_t;


 /* packet trace format function */
 static u8 *
 format_l2flood_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 *);
   l2flood_trace_t *t = va_arg (*args, l2flood_trace_t *);

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

 l2flood_main_t l2flood_main;

 static vlib_node_registration_t l2flood_node;

 #define foreach_l2flood_error					\
 _(L2FLOOD,           "L2 flood packets")			\
 _(REPL_FAIL,         "L2 replication failures")			\
 _(NO_MEMBERS,        "L2 replication complete")			\
 _(BVI_BAD_MAC,       "BVI L3 mac mismatch")		        \
 _(BVI_ETHERTYPE,     "BVI packet with unhandled ethertype")

 typedef enum
 {
 #define _(sym,str) L2FLOOD_ERROR_##sym,
   foreach_l2flood_error
 #undef _
     L2FLOOD_N_ERROR,
 } l2flood_error_t;

 static char *l2flood_error_strings[] = {
 #define _(sym,string) string,
   foreach_l2flood_error
 #undef _
 };

 typedef enum
 {
   L2FLOOD_NEXT_L2_OUTPUT,
   L2FLOOD_NEXT_DROP,
   L2FLOOD_N_NEXT,
 } l2flood_next_t;

 /*
  * Perform flooding on one packet
  *
  * Due to the way BVI processing can modify the packet, the BVI interface
  * (if present) must be processed last in the replication. The member vector
  * is arranged so that the BVI interface is always the first element.
  * Flooding walks the vector in reverse.
  *
  * BVI processing causes the packet to go to L3 processing. This strips the
  * L2 header, which is fine because the replication infrastructure restores
  * it. However L3 processing can trigger larger changes to the packet. For
  * example, an ARP request could be turned into an ARP reply, an ICMP request
  * could be turned into an ICMP reply. If BVI processing is not performed
  * last, the modified packet would be replicated to the remaining members.
  */

 static_always_inline void
 l2flood_process (vlib_main_t * vm,
 		 vlib_node_runtime_t * node,
 		 l2flood_main_t * msm,
 		 u64 * counter_base,
 		 vlib_buffer_t * b0,
 		 u32 * sw_if_index0,
 		 l2fib_entry_key_t * key0,
 		 u32 * bucket0, l2fib_entry_result_t * result0, u32 * next0)
 {
   u16 bd_index0;
   l2_bridge_domain_t *bd_config;
   l2_flood_member_t *members;
   i32 current_member;		/* signed */
   replication_context_t *ctx;
   u8 in_shg = vnet_buffer (b0)->l2.shg;

   if (!replication_is_recycled (b0))
     {

       /* Do flood "prep node" processing */

       /* Get config for the bridge domain interface */
       bd_index0 = vnet_buffer (b0)->l2.bd_index;
       bd_config = vec_elt_at_index (l2input_main.bd_configs, bd_index0);
       members = bd_config->members;

       /* Find first member that passes the reflection and SHG checks */
       current_member = bd_config->flood_count - 1;
       while ((current_member >= 0) &&
 	     ((members[current_member].sw_if_index == *sw_if_index0) ||
 	      (in_shg && members[current_member].shg == in_shg)))
 	{
 	  current_member--;
 	}

       if (current_member < 0)
 	{
 	  /* No members to flood to */
 	  *next0 = L2FLOOD_NEXT_DROP;
 	  b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
 	  return;
 	}

       if ((current_member > 0) &&
 	  ((current_member > 1) ||
 	   ((members[0].sw_if_index != *sw_if_index0) &&
 	    (!in_shg || members[0].shg != in_shg))))
 	{
 	  /* If more than one member then initiate replication */
 	  ctx =
 	    replication_prep (vm, b0, l2flood_node.index, 1 /* l2_packet */ );
 	  ctx->feature_replicas = (uword) members;
 	  ctx->feature_counter = current_member;
 	}

     }
   else
     {
       vnet_buffer_opaque_t *vnet_buff_op;

       /* Do flood "recycle node" processing */

       if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_REPL_FAIL))
 	{
 	  (void) replication_recycle (vm, b0, 1 /* is_last */ );
 	  *next0 = L2FLOOD_NEXT_DROP;
 	  b0->error = node->errors[L2FLOOD_ERROR_REPL_FAIL];
 	  return;
 	}

       ctx = replication_get_ctx (b0);
       replication_clear_recycled (b0);

       members = (l2_flood_member_t *) (intptr_t) ctx->feature_replicas;
       current_member = (i32) ctx->feature_counter - 1;

       /* Need to update input index from saved packet context */
       vnet_buff_op = (vnet_buffer_opaque_t *) ctx->vnet_buffer;
       *sw_if_index0 = vnet_buff_op->sw_if_index[VLIB_RX];

       /* Find next member that passes the reflection and SHG check */
       while ((current_member >= 0) &&
 	     ((members[current_member].sw_if_index == *sw_if_index0) ||
 	      (in_shg && members[current_member].shg == in_shg)))
 	{
 	  current_member--;
 	}

       if (current_member < 0)
 	{
 	  /*
 	   * No more members to flood to.
 	   * Terminate replication and drop packet.
 	   */

 	  replication_recycle (vm, b0, 1 /* is_last */ );

 	  *next0 = L2FLOOD_NEXT_DROP;
 	  /* Ideally we woudn't bump a counter here, just silently complete */
 	  b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
 	  return;
 	}

       /* Restore packet and context and continue replication */
       ctx->feature_counter = current_member;
       replication_recycle (vm, b0, ((current_member == 0) ||	/*is_last */
 				    ((current_member == 1) &&
 				     ((members[0].sw_if_index ==
 				       *sw_if_index0) || (in_shg
 							  && members[0].shg ==
 							  in_shg)))));
     }

   /* Forward packet to the current member */
   if (PREDICT_FALSE (members[current_member].flags & L2_FLOOD_MEMBER_BVI))
     {
       /* Do BVI processing */
       u32 rc;
       rc = l2_to_bvi (vm,
 		      msm->vnet_main,
 		      b0,
 		      members[current_member].sw_if_index,
 		      &msm->l3_next, next0);

       if (PREDICT_FALSE (rc))
 	{
 	  if (rc == TO_BVI_ERR_BAD_MAC)
 	    {
 	      b0->error = node->errors[L2FLOOD_ERROR_BVI_BAD_MAC];
 	      *next0 = L2FLOOD_NEXT_DROP;
 	    }
 	  else if (rc == TO_BVI_ERR_ETHERTYPE)
 	    {
 	      b0->error = node->errors[L2FLOOD_ERROR_BVI_ETHERTYPE];
 	      *next0 = L2FLOOD_NEXT_DROP;
 	    }
 	}
     }
   else
     {
       /* Do normal L2 forwarding */
       vnet_buffer (b0)->sw_if_index[VLIB_TX] =
 	members[current_member].sw_if_index;
       *next0 = L2FLOOD_NEXT_L2_OUTPUT;

     }

 }


 static uword
 l2flood_node_fn (vlib_main_t * vm,
 		 vlib_node_runtime_t * node, vlib_frame_t * frame)
 {
   u32 n_left_from, *from, *to_next;
   l2flood_next_t next_index;
   l2flood_main_t *msm = &l2flood_main;
   vlib_node_t *n = vlib_get_node (vm, l2flood_node.index);
   u32 node_counter_base_index = n->error_heap_index;
   vlib_error_main_t *em = &vm->error_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 >= 6 && n_left_to_next >= 2)
 	{
 	  u32 bi0, bi1;
 	  vlib_buffer_t *b0, *b1;
 	  u32 next0, next1;
 	  u32 sw_if_index0, sw_if_index1;
 	  l2fib_entry_key_t key0, key1;
 	  l2fib_entry_result_t result0, result1;
 	  u32 bucket0, bucket1;

 	  /* Prefetch next iteration. */
 	  {
 	    vlib_buffer_t *p2, *p3, *p4, *p5;

 	    p2 = vlib_get_buffer (vm, from[2]);
 	    p3 = vlib_get_buffer (vm, from[3]);
 	    p4 = vlib_get_buffer (vm, from[4]);
 	    p5 = vlib_get_buffer (vm, from[5]);

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

 	    /* Prefetch the replication context for the N+1 loop iteration */
 	    /* This depends on the buffer header above */
 	    replication_prefetch_ctx (p2);
 	    replication_prefetch_ctx (p3);

 	    /* Prefetch the packet for the N+1 loop iteration */
 	    CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
 	    CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
 	  }

 	  /* 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];
 	  from += 2;
 	  to_next += 2;
 	  n_left_from -= 2;
 	  n_left_to_next -= 2;

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

 	  /* 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];

 	  /* process 2 pkts */
 	  em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 2;

 	  l2flood_process (vm, node, msm,
 			   &em->counters[node_counter_base_index], b0,
 			   &sw_if_index0, &key0, &bucket0, &result0, &next0);

 	  l2flood_process (vm, node, msm,
 			   &em->counters[node_counter_base_index], b1,
 			   &sw_if_index1, &key1, &bucket1, &result1, &next1);

 	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
 	    {
 	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 		{
 		  l2flood_trace_t *t =
 		    vlib_add_trace (vm, node, b0, sizeof (*t));
 		  ethernet_header_t *h0 = vlib_buffer_get_current (b0);
 		  t->sw_if_index = sw_if_index0;
 		  t->bd_index = vnet_buffer (b0)->l2.bd_index;
 		  clib_memcpy (t->src, h0->src_address, 6);
 		  clib_memcpy (t->dst, h0->dst_address, 6);
 		}
 	      if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
 		{
 		  l2flood_trace_t *t =
 		    vlib_add_trace (vm, node, b1, sizeof (*t));
 		  ethernet_header_t *h1 = vlib_buffer_get_current (b1);
 		  t->sw_if_index = sw_if_index1;
 		  t->bd_index = vnet_buffer (b1)->l2.bd_index;
 		  clib_memcpy (t->src, h1->src_address, 6);
 		  clib_memcpy (t->dst, h1->dst_address, 6);
 		}
 	    }

 	  /* verify speculative enqueues, maybe switch current next frame */
 	  /* if next0==next1==next_index then nothing special needs to be done */
 	  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;
 	  u32 next0;
 	  u32 sw_if_index0;
 	  l2fib_entry_key_t key0;
 	  l2fib_entry_result_t result0;
 	  u32 bucket0;

 	  /* 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);

 	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];

 	  /* process 1 pkt */
 	  em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 1;

 	  l2flood_process (vm, node, msm,
 			   &em->counters[node_counter_base_index], b0,
 			   &sw_if_index0, &key0, &bucket0, &result0, &next0);

 	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
 			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	    {
 	      l2flood_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 	      ethernet_header_t *h0 = vlib_buffer_get_current (b0);
 	      t->sw_if_index = sw_if_index0;
 	      t->bd_index = vnet_buffer (b0)->l2.bd_index;
 	      clib_memcpy (t->src, h0->src_address, 6);
 	      clib_memcpy (t->dst, h0->dst_address, 6);
 	    }

 	  /* 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);
     }

   return frame->n_vectors;
 }


 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (l2flood_node,static) = {
   .function = l2flood_node_fn,
   .name = "l2-flood",
   .vector_size = sizeof (u32),
   .format_trace = format_l2flood_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,

   .n_errors = ARRAY_LEN(l2flood_error_strings),
   .error_strings = l2flood_error_strings,

   .n_next_nodes = L2FLOOD_N_NEXT,

   /* edit / add dispositions here */
   .next_nodes = {
         [L2FLOOD_NEXT_L2_OUTPUT] = "l2-output",
         [L2FLOOD_NEXT_DROP] = "error-drop",
   },
 };
 /* *INDENT-ON* */

 VLIB_NODE_FUNCTION_MULTIARCH (l2flood_node, l2flood_node_fn)
      clib_error_t *l2flood_init (vlib_main_t * vm)
 {
   l2flood_main_t *mp = &l2flood_main;

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

   /* Initialize the feature next-node indexes */
   feat_bitmap_init_next_nodes (vm,
 			       l2flood_node.index,
 			       L2INPUT_N_FEAT,
 			       l2input_get_feat_names (),
 			       mp->feat_next_node_index);

   return 0;
 }

 VLIB_INIT_FUNCTION (l2flood_init);


 /** Add the L3 input node for this ethertype to the next nodes structure. */
 void
 l2flood_register_input_type (vlib_main_t * vm,
 			     ethernet_type_t type, u32 node_index)
 {
   l2flood_main_t *mp = &l2flood_main;
   u32 next_index;

   next_index = vlib_node_add_next (vm, l2flood_node.index, node_index);

   next_by_ethertype_register (&mp->l3_next, type, next_index);
 }


 /**
  * Set subinterface flood enable/disable.
  * The CLI format is:
  * set interface l2 flood <interface> [disable]
  */
 static clib_error_t *
 int_flood (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 enable;

   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;
     }

   enable = 1;
   if (unformat (input, "disable"))
     {
       enable = 0;
     }

   /* set the interface flag */
   l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_FLOOD, enable);

 done:
   return error;
 }

 /*?
  * Layer 2 flooding can be enabled and disabled on each
  * interface and on each bridge-domain. Use this command to
  * manage interfaces. It is enabled by default.
  *
  * @cliexpar
  * Example of how to enable flooding:
  * @cliexcmd{set interface l2 flood GigabitEthernet0/8/0}
  * Example of how to disable flooding:
  * @cliexcmd{set interface l2 flood GigabitEthernet0/8/0 disable}
 ?*/
 /* *INDENT-OFF* */
 VLIB_CLI_COMMAND (int_flood_cli, static) = {
   .path = "set interface l2 flood",
   .short_help = "set interface l2 flood <interface> [disable]",
   .function = int_flood,
 };
 /* *INDENT-ON* */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* l2_flood.c : layer 2 flooding
	*
	* 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 <vlib/cli.h>
	#include <vnet/l2/l2_input.h>
	#include <vnet/l2/feat_bitmap.h>
	#include <vnet/l2/l2_bvi.h>
	#include <vnet/replication.h>
	#include <vnet/l2/l2_fib.h>

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


	/**
	* @file
	* @brief Ethernet Flooding.
	*
	* Flooding uses the packet replication infrastructure to send a copy of the
	* packet to each member interface. Logically the replication infrastructure
	* expects two graph nodes: a prep node that initiates replication and sends the
	* packet to the first destination, and a recycle node that is passed the packet
	* after it has been transmitted.
	*
	* To decrease the amount of code, l2 flooding implements both functions in
	* the same graph node. This node can tell if is it being called as the "prep"
	* or "recycle" using replication_is_recycled().
	*/


	typedef struct
	{

	/* Next nodes for each feature */
	u32 feat_next_node_index[32];

	/* next node index for the L3 input node of each ethertype */
	next_by_ethertype_t l3_next;

	/* convenience variables */
	vlib_main_t *vlib_main;
	vnet_main_t *vnet_main;
	} l2flood_main_t;

	typedef struct
	{
	u8 src[6];
	u8 dst[6];
	u32 sw_if_index;
	u16 bd_index;
	} l2flood_trace_t;


	/* packet trace format function */
	static u8 *
	format_l2flood_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 );
	l2flood_trace_t t = va_arg (args, l2flood_trace_t *);

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

	l2flood_main_t l2flood_main;

	static vlib_node_registration_t l2flood_node;

	#define foreach_l2flood_error \
	_(L2FLOOD, "L2 flood packets") \
	_(REPL_FAIL, "L2 replication failures") \
	_(NO_MEMBERS, "L2 replication complete") \
	_(BVI_BAD_MAC, "BVI L3 mac mismatch") \
	_(BVI_ETHERTYPE, "BVI packet with unhandled ethertype")

	typedef enum
	{
	#define _(sym,str) L2FLOOD_ERROR_##sym,
	foreach_l2flood_error
	#undef _
	L2FLOOD_N_ERROR,
	} l2flood_error_t;

	static char *l2flood_error_strings[] = {
	#define _(sym,string) string,
	foreach_l2flood_error
	#undef _
	};

	typedef enum
	{
	L2FLOOD_NEXT_L2_OUTPUT,
	L2FLOOD_NEXT_DROP,
	L2FLOOD_N_NEXT,
	} l2flood_next_t;

	/*
	* Perform flooding on one packet
	*
	* Due to the way BVI processing can modify the packet, the BVI interface
	* (if present) must be processed last in the replication. The member vector
	* is arranged so that the BVI interface is always the first element.
	* Flooding walks the vector in reverse.
	*
	* BVI processing causes the packet to go to L3 processing. This strips the
	* L2 header, which is fine because the replication infrastructure restores
	* it. However L3 processing can trigger larger changes to the packet. For
	* example, an ARP request could be turned into an ARP reply, an ICMP request
	* could be turned into an ICMP reply. If BVI processing is not performed
	* last, the modified packet would be replicated to the remaining members.
	*/

	static_always_inline void
	l2flood_process (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	l2flood_main_t * msm,
	u64 * counter_base,
	vlib_buffer_t * b0,
	u32 * sw_if_index0,
	l2fib_entry_key_t * key0,
	u32 * bucket0, l2fib_entry_result_t * result0, u32 * next0)
	{
	u16 bd_index0;
	l2_bridge_domain_t *bd_config;
	l2_flood_member_t *members;
	i32 current_member; /* signed */
	replication_context_t *ctx;
	u8 in_shg = vnet_buffer (b0)->l2.shg;

	if (!replication_is_recycled (b0))
	{

	/* Do flood "prep node" processing */

	/* Get config for the bridge domain interface */
	bd_index0 = vnet_buffer (b0)->l2.bd_index;
	bd_config = vec_elt_at_index (l2input_main.bd_configs, bd_index0);
	members = bd_config->members;

	/* Find first member that passes the reflection and SHG checks */
	current_member = bd_config->flood_count - 1;
	while ((current_member >= 0) &&
	((members[current_member].sw_if_index == *sw_if_index0) \|\|
	(in_shg && members[current_member].shg == in_shg)))
	{
	current_member--;
	}

	if (current_member < 0)
	{
	/* No members to flood to */
	*next0 = L2FLOOD_NEXT_DROP;
	b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
	return;
	}

	if ((current_member > 0) &&
	((current_member > 1) \|\|
	((members[0].sw_if_index != *sw_if_index0) &&
	(!in_shg \|\| members[0].shg != in_shg))))
	{
	/* If more than one member then initiate replication */
	ctx =
	replication_prep (vm, b0, l2flood_node.index, 1 /* l2_packet */ );
	ctx->feature_replicas = (uword) members;
	ctx->feature_counter = current_member;
	}

	}
	else
	{
	vnet_buffer_opaque_t *vnet_buff_op;

	/* Do flood "recycle node" processing */

	if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_REPL_FAIL))
	{
	(void) replication_recycle (vm, b0, 1 /* is_last */ );
	*next0 = L2FLOOD_NEXT_DROP;
	b0->error = node->errors[L2FLOOD_ERROR_REPL_FAIL];
	return;
	}

	ctx = replication_get_ctx (b0);
	replication_clear_recycled (b0);

	members = (l2_flood_member_t *) (intptr_t) ctx->feature_replicas;
	current_member = (i32) ctx->feature_counter - 1;

	/* Need to update input index from saved packet context */
	vnet_buff_op = (vnet_buffer_opaque_t *) ctx->vnet_buffer;
	*sw_if_index0 = vnet_buff_op->sw_if_index[VLIB_RX];

	/* Find next member that passes the reflection and SHG check */
	while ((current_member >= 0) &&
	((members[current_member].sw_if_index == *sw_if_index0) \|\|
	(in_shg && members[current_member].shg == in_shg)))
	{
	current_member--;
	}

	if (current_member < 0)
	{
	/*
	* No more members to flood to.
	* Terminate replication and drop packet.
	*/

	replication_recycle (vm, b0, 1 /* is_last */ );

	*next0 = L2FLOOD_NEXT_DROP;
	/* Ideally we woudn't bump a counter here, just silently complete */
	b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
	return;
	}

	/* Restore packet and context and continue replication */
	ctx->feature_counter = current_member;
	replication_recycle (vm, b0, ((current_member == 0) \|\| /is_last /
	((current_member == 1) &&
	((members[0].sw_if_index ==
	*sw_if_index0) \|\| (in_shg
	&& members[0].shg ==
	in_shg)))));
	}

	/* Forward packet to the current member */
	if (PREDICT_FALSE (members[current_member].flags & L2_FLOOD_MEMBER_BVI))
	{
	/* Do BVI processing */
	u32 rc;
	rc = l2_to_bvi (vm,
	msm->vnet_main,
	b0,
	members[current_member].sw_if_index,
	&msm->l3_next, next0);

	if (PREDICT_FALSE (rc))
	{
	if (rc == TO_BVI_ERR_BAD_MAC)
	{
	b0->error = node->errors[L2FLOOD_ERROR_BVI_BAD_MAC];
	*next0 = L2FLOOD_NEXT_DROP;
	}
	else if (rc == TO_BVI_ERR_ETHERTYPE)
	{
	b0->error = node->errors[L2FLOOD_ERROR_BVI_ETHERTYPE];
	*next0 = L2FLOOD_NEXT_DROP;
	}
	}
	}
	else
	{
	/* Do normal L2 forwarding */
	vnet_buffer (b0)->sw_if_index[VLIB_TX] =
	members[current_member].sw_if_index;
	*next0 = L2FLOOD_NEXT_L2_OUTPUT;

	}

	}


	static uword
	l2flood_node_fn (vlib_main_t * vm,
	vlib_node_runtime_t * node, vlib_frame_t * frame)
	{
	u32 n_left_from, from, to_next;
	l2flood_next_t next_index;
	l2flood_main_t *msm = &l2flood_main;
	vlib_node_t *n = vlib_get_node (vm, l2flood_node.index);
	u32 node_counter_base_index = n->error_heap_index;
	vlib_error_main_t *em = &vm->error_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 >= 6 && n_left_to_next >= 2)
	{
	u32 bi0, bi1;
	vlib_buffer_t b0, b1;
	u32 next0, next1;
	u32 sw_if_index0, sw_if_index1;
	l2fib_entry_key_t key0, key1;
	l2fib_entry_result_t result0, result1;
	u32 bucket0, bucket1;

	/* Prefetch next iteration. */
	{
	vlib_buffer_t p2, p3, p4, p5;

	p2 = vlib_get_buffer (vm, from[2]);
	p3 = vlib_get_buffer (vm, from[3]);
	p4 = vlib_get_buffer (vm, from[4]);
	p5 = vlib_get_buffer (vm, from[5]);

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

	/* Prefetch the replication context for the N+1 loop iteration */
	/* This depends on the buffer header above */
	replication_prefetch_ctx (p2);
	replication_prefetch_ctx (p3);

	/* Prefetch the packet for the N+1 loop iteration */
	CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
	CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
	}

	/* 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];
	from += 2;
	to_next += 2;
	n_left_from -= 2;
	n_left_to_next -= 2;

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

	/* 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];

	/* process 2 pkts */
	em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 2;

	l2flood_process (vm, node, msm,
	&em->counters[node_counter_base_index], b0,
	&sw_if_index0, &key0, &bucket0, &result0, &next0);

	l2flood_process (vm, node, msm,
	&em->counters[node_counter_base_index], b1,
	&sw_if_index1, &key1, &bucket1, &result1, &next1);

	if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
	{
	if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	l2flood_trace_t *t =
	vlib_add_trace (vm, node, b0, sizeof (*t));
	ethernet_header_t *h0 = vlib_buffer_get_current (b0);
	t->sw_if_index = sw_if_index0;
	t->bd_index = vnet_buffer (b0)->l2.bd_index;
	clib_memcpy (t->src, h0->src_address, 6);
	clib_memcpy (t->dst, h0->dst_address, 6);
	}
	if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	{
	l2flood_trace_t *t =
	vlib_add_trace (vm, node, b1, sizeof (*t));
	ethernet_header_t *h1 = vlib_buffer_get_current (b1);
	t->sw_if_index = sw_if_index1;
	t->bd_index = vnet_buffer (b1)->l2.bd_index;
	clib_memcpy (t->src, h1->src_address, 6);
	clib_memcpy (t->dst, h1->dst_address, 6);
	}
	}

	/* verify speculative enqueues, maybe switch current next frame */
	/* if next0==next1==next_index then nothing special needs to be done */
	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;
	u32 next0;
	u32 sw_if_index0;
	l2fib_entry_key_t key0;
	l2fib_entry_result_t result0;
	u32 bucket0;

	/* 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);

	sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];

	/* process 1 pkt */
	em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 1;

	l2flood_process (vm, node, msm,
	&em->counters[node_counter_base_index], b0,
	&sw_if_index0, &key0, &bucket0, &result0, &next0);

	if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
	(b0->flags & VLIB_BUFFER_IS_TRACED)))
	{
	l2flood_trace_t t = vlib_add_trace (vm, node, b0, sizeof (t));
	ethernet_header_t *h0 = vlib_buffer_get_current (b0);
	t->sw_if_index = sw_if_index0;
	t->bd_index = vnet_buffer (b0)->l2.bd_index;
	clib_memcpy (t->src, h0->src_address, 6);
	clib_memcpy (t->dst, h0->dst_address, 6);
	}

	/* 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);
	}

	return frame->n_vectors;
	}


	/* INDENT-OFF */
	VLIB_REGISTER_NODE (l2flood_node,static) = {
	.function = l2flood_node_fn,
	.name = "l2-flood",
	.vector_size = sizeof (u32),
	.format_trace = format_l2flood_trace,
	.type = VLIB_NODE_TYPE_INTERNAL,

	.n_errors = ARRAY_LEN(l2flood_error_strings),
	.error_strings = l2flood_error_strings,

	.n_next_nodes = L2FLOOD_N_NEXT,

	/* edit / add dispositions here */
	.next_nodes = {
	[L2FLOOD_NEXT_L2_OUTPUT] = "l2-output",
	[L2FLOOD_NEXT_DROP] = "error-drop",
	},
	};
	/* INDENT-ON */

	VLIB_NODE_FUNCTION_MULTIARCH (l2flood_node, l2flood_node_fn)
	clib_error_t l2flood_init (vlib_main_t vm)
	{
	l2flood_main_t *mp = &l2flood_main;

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

	/* Initialize the feature next-node indexes */
	feat_bitmap_init_next_nodes (vm,
	l2flood_node.index,
	L2INPUT_N_FEAT,
	l2input_get_feat_names (),
	mp->feat_next_node_index);

	return 0;
	}

	VLIB_INIT_FUNCTION (l2flood_init);



	/** Add the L3 input node for this ethertype to the next nodes structure. */
	void
	l2flood_register_input_type (vlib_main_t * vm,
	ethernet_type_t type, u32 node_index)
	{
	l2flood_main_t *mp = &l2flood_main;
	u32 next_index;

	next_index = vlib_node_add_next (vm, l2flood_node.index, node_index);

	next_by_ethertype_register (&mp->l3_next, type, next_index);
	}


	/**
	* Set subinterface flood enable/disable.
	* The CLI format is:
	* set interface l2 flood <interface> [disable]
	*/
	static clib_error_t *
	int_flood (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 enable;

	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;
	}

	enable = 1;
	if (unformat (input, "disable"))
	{
	enable = 0;
	}

	/* set the interface flag */
	l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_FLOOD, enable);

	done:
	return error;
	}

	/*?
	* Layer 2 flooding can be enabled and disabled on each
	* interface and on each bridge-domain. Use this command to
	* manage interfaces. It is enabled by default.
	*
	* @cliexpar
	* Example of how to enable flooding:
	* @cliexcmd{set interface l2 flood GigabitEthernet0/8/0}
	* Example of how to disable flooding:
	* @cliexcmd{set interface l2 flood GigabitEthernet0/8/0 disable}
	?*/
	/* INDENT-OFF */
	VLIB_CLI_COMMAND (int_flood_cli, static) = {
	.path = "set interface l2 flood",
	.short_help = "set interface l2 flood <interface> [disable]",
	.function = int_flood,
	};
	/* INDENT-ON */

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