l2: input performance

Type: improvement

- cache the values form the BD on the input config to avoid loading
- avoid the short write long read on the sequence number
- use vlib_buffer_enqueue_to_next

Signed-off-by: Neale Ranns <nranns@cisco.com>
Change-Id: I33442b9104b457e4c638d26e9ad3bc965687a0bc

11 files changed, 693 insertions, 469 deletions

diff --git a/src/vnet/l2/l2_api.c b/src/vnet/l2/l2_api.c
index d9bc47ab2e8..c8690c6ccae 100644
--- a/src/vnet/l2/l2_api.c
+++ b/src/vnet/l2/l2_api.c
@@ -115,7 +115,7 @@ vl_api_l2_xconnect_dump_t_handler (vl_api_l2_xconnect_dump_t * mp)
   pool_foreach (swif, im->sw_interfaces,
   ({
     config = vec_elt_at_index (l2im->configs, swif->sw_if_index);
-    if (config->xconnect)
+    if (l2_input_is_xconnect(config))
       send_l2_xconnect_details (reg, mp->context, swif->sw_if_index,
                                 config->output_sw_if_index);
   }));
@@ -236,7 +236,7 @@ vl_api_l2fib_add_del_t_handler (vl_api_l2fib_add_del_t * mp)
 	    {
 	      l2_input_config_t *config;
 	      config = vec_elt_at_index (l2im->configs, sw_if_index);
-	      if (config->bridge == 0)
+	      if (!l2_input_is_bridge (config))
 		{
 		  rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
 		  goto bad_sw_if_index;
diff --git a/src/vnet/l2/l2_arp_term.c b/src/vnet/l2/l2_arp_term.c
index 982fd9f05ea..fd21bc433e5 100644
--- a/src/vnet/l2/l2_arp_term.c
+++ b/src/vnet/l2/l2_arp_term.c
@@ -377,7 +377,7 @@ arp_term_l2bd (vlib_main_t * vm,
 	  /* For BVI, need to use l2-fwd node to send ARP reply as
 	     l2-output node cannot output packet to BVI properly */
 	  cfg0 = vec_elt_at_index (l2im->configs, sw_if_index0);
-	  if (PREDICT_FALSE (cfg0->bvi))
+	  if (PREDICT_FALSE (l2_input_is_bvi (cfg0)))
 	    {
 	      vnet_buffer (p0)->l2.feature_bitmap |= L2INPUT_FEAT_FWD;
 	      vnet_buffer (p0)->sw_if_index[VLIB_RX] = 0;
diff --git a/src/vnet/l2/l2_bd.c b/src/vnet/l2/l2_bd.c
index 94852c90769..a3acc4b6d7e 100644
--- a/src/vnet/l2/l2_bd.c
+++ b/src/vnet/l2/l2_bd.c
@@ -243,6 +243,43 @@ l2bd_init (vlib_main_t * vm)
 
 VLIB_INIT_FUNCTION (l2bd_init);
 
+l2_bridge_domain_t *
+bd_get (u32 bd_index)
+{
+  if (bd_index < vec_len (l2input_main.bd_configs))
+    return (vec_elt_at_index (l2input_main.bd_configs, bd_index));
+  return (NULL);
+}
+
+u32
+bd_input_walk (u32 bd_index, bd_input_walk_fn_t fn, void *data)
+{
+  l2_flood_member_t *member;
+  l2_bridge_domain_t *bd;
+  u32 sw_if_index;
+
+  sw_if_index = ~0;
+  bd = bd_get (bd_index);
+
+  ASSERT (bd);
+
+  vec_foreach (member, bd->members)
+  {
+    if (WALK_STOP == fn (bd_index, member->sw_if_index))
+      {
+	sw_if_index = member->sw_if_index;
+	break;
+      }
+  }
+
+  return (sw_if_index);
+}
+
+static void
+b2_input_recache (u32 bd_index)
+{
+  bd_input_walk (bd_index, l2input_recache, NULL);
+}
 
 /**
     Set the learn/forward/flood flags for the bridge domain.
@@ -290,6 +327,8 @@ bd_set_flags (vlib_main_t * vm, u32 bd_index, bd_flags_t flags, u32 enable)
       bd_config->feature_bitmap &= ~feature_bitmap;
     }
 
+  b2_input_recache (bd_index);
+
   return bd_config->feature_bitmap;
 }
 
@@ -305,6 +344,7 @@ bd_set_mac_age (vlib_main_t * vm, u32 bd_index, u8 age)
   vec_validate (l2input_main.bd_configs, bd_index);
   bd_config = vec_elt_at_index (l2input_main.bd_configs, bd_index);
   bd_config->mac_age = age;
+  b2_input_recache (bd_index);
 
   /* check if there is at least one bd with mac aging enabled */
   vec_foreach (bd_config, l2input_main.bd_configs)
@@ -1093,8 +1133,8 @@ bd_show (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
 	  else
 	    as = format (as, "off");
 	  vlib_cli_output (vm,
-			   "%=8d %=7d %=4d %=9v %=9s %=9s %=11U %=9s %=9s %=9s %=11U",
-			   bd_config->bd_id, bd_index, bd_config->seq_num, as,
+			   "%=8d %=7d %=9v %=9s %=9s %=11U %=9s %=9s %=9s %=11U",
+			   bd_config->bd_id, bd_index, as,
 			   bd_config->feature_bitmap & L2INPUT_FEAT_LEARN ?
 			   "on" : "off",
 			   bd_config->feature_bitmap & L2INPUT_FEAT_FWD ?
@@ -1108,6 +1148,8 @@ bd_show (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
 			   "on" : "off",
 			   format_vnet_sw_if_index_name_with_NA,
 			   vnm, bd_config->bvi_sw_if_index);
+	  vlib_cli_output (vm, "%U", format_l2_input_feature_bitmap,
+			   bd_config->feature_bitmap);
 	  vec_reset_length (as);
 
 	  if (detail || intf)
@@ -1118,7 +1160,7 @@ bd_show (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
 	      {
 		l2_flood_member_t *member =
 		  vec_elt_at_index (bd_config->members, i);
-		u8 swif_seq_num = *l2fib_swif_seq_num (member->sw_if_index);
+		u8 swif_seq_num = l2_input_seq_num (member->sw_if_index);
 		u32 vtr_opr, dot1q, tag1, tag2;
 		if (i == 0)
 		  {
diff --git a/src/vnet/l2/l2_bd.h b/src/vnet/l2/l2_bd.h
index 35c0e0bf0a1..943358b4e15 100644
--- a/src/vnet/l2/l2_bd.h
+++ b/src/vnet/l2/l2_bd.h
@@ -139,7 +139,6 @@ bd_is_valid (l2_bridge_domain_t * bd_config)
 /* Init bridge domain if not done already */
 void bd_validate (l2_bridge_domain_t * bd_config);
 
-
 void
 bd_add_member (l2_bridge_domain_t * bd_config, l2_flood_member_t * member);
 
@@ -201,6 +200,16 @@ bd_find_or_add_bd_index (bd_main_t * bdm, u32 bd_id)
   return bd_index;
 }
 
+/**
+ * \brief Walk all the input interfaces in the BD
+ */
+typedef walk_rc_t (*bd_input_walk_fn_t) (u32 bd_index, u32 sw_if_index);
+
+u32 bd_input_walk (u32 bd_index, bd_input_walk_fn_t fn, void *data);
+
+l2_bridge_domain_t *bd_get (u32 bd_index);
+l2_bridge_domain_t *bd_get_by_table_id (u32 table_id);
+
 u32 bd_add_del_ip_mac (u32 bd_index,
 		       ip46_type_t type,
 		       const ip46_address_t * ip_addr,
diff --git a/src/vnet/l2/l2_fib.c b/src/vnet/l2/l2_fib.c
index 4b7fdcb28b5..bb4d61404a2 100644
--- a/src/vnet/l2/l2_fib.c
+++ b/src/vnet/l2/l2_fib.c
@@ -146,6 +146,26 @@ l2fib_table_dump (u32 bd_index,
   *l2fe_res = ctx.l2fe_res;
 }
 
+void
+l2_fib_extract_seq_num (l2fib_seq_num_t sn, u8 * bd_sn, u8 * if_sn)
+{
+  *bd_sn = sn >> 8;
+  *if_sn = sn & 0xff;
+}
+
+u8 *
+format_l2_fib_seq_num (u8 * s, va_list * a)
+{
+  l2fib_seq_num_t sn = va_arg (*a, int);
+  u8 bd_sn, if_sn;
+
+  l2_fib_extract_seq_num (sn, &bd_sn, &if_sn);
+
+  s = format (s, "%3d/%-3d", bd_sn, if_sn);
+
+  return (s);
+}
+
 typedef struct l2fib_show_walk_ctx_t_
 {
   u8 first_entry;
@@ -207,12 +227,12 @@ l2fib_show_walk_cb (BVT (clib_bihash_kv) * kvp, void *arg)
 	}
 
       vlib_cli_output (ctx->vm,
-		       "%=19U%=7d%=7d %3d/%-3d%=9v%=7s%=7s%=5s%=30U",
+		       "%=19U%=7d%=7d %U%=9v%=7s%=7s%=5s%=30U",
 		       format_ethernet_address, key.fields.mac,
 		       key.fields.bd_index,
 		       result.fields.sw_if_index == ~0
 		       ? -1 : result.fields.sw_if_index,
-		       result.fields.sn.bd, result.fields.sn.swif, s,
+		       format_l2_fib_seq_num, result.fields.sn, s,
 		       l2fib_entry_result_is_set_STATIC (&result) ? "*" : "-",
 		       l2fib_entry_result_is_set_FILTER (&result) ? "*" : "-",
 		       l2fib_entry_result_is_set_BVI (&result) ? "*" : "-",
@@ -404,16 +424,13 @@ VLIB_CLI_COMMAND (clear_l2fib_cli, static) = {
 };
 /* *INDENT-ON* */
 
-static inline l2fib_seq_num_t
+static l2fib_seq_num_t
 l2fib_cur_seq_num (u32 bd_index, u32 sw_if_index)
 {
   l2_bridge_domain_t *bd_config = l2input_bd_config (bd_index);
-  /* *INDENT-OFF* */
-  return (l2fib_seq_num_t) {
-    .swif = *l2fib_swif_seq_num (sw_if_index),
-    .bd = bd_config->seq_num,
-  };
-  /* *INDENT-ON* */
+
+  return l2_fib_mk_seq_num (bd_config->seq_num,
+			    l2_input_seq_num (sw_if_index));
 }
 
 /**
@@ -835,7 +852,7 @@ l2fib_start_ager_scan (vlib_main_t * vm)
 void
 l2fib_flush_int_mac (vlib_main_t * vm, u32 sw_if_index)
 {
-  *l2fib_swif_seq_num (sw_if_index) += 1;
+  l2_input_seq_num_inc (sw_if_index);
   l2fib_start_ager_scan (vm);
 }
 
@@ -989,7 +1006,8 @@ clib_error_t *
 l2fib_sw_interface_up_down (vnet_main_t * vnm, u32 sw_if_index, u32 flags)
 {
   l2_input_config_t *config = l2input_intf_config (sw_if_index);
-  if ((flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) == 0 && config->bridge)
+  if ((flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) == 0 &&
+      l2_input_is_bridge (config))
     l2fib_flush_int_mac (vnm->vlib_main, sw_if_index);
   return 0;
 }
@@ -1136,8 +1154,8 @@ l2fib_scan (vlib_main_t * vm, f64 start_time, u8 event_only)
 	      /* start aging processing */
 	      u32 bd_index = key.fields.bd_index;
 	      u32 sw_if_index = result.fields.sw_if_index;
-	      u16 sn = l2fib_cur_seq_num (bd_index, sw_if_index).as_u16;
-	      if (result.fields.sn.as_u16 != sn)
+	      u16 sn = l2fib_cur_seq_num (bd_index, sw_if_index);
+	      if (result.fields.sn != sn)
 		goto age_out;	/* stale mac */
 
 	      l2_bridge_domain_t *bd_config =
diff --git a/src/vnet/l2/l2_fib.h b/src/vnet/l2/l2_fib.h
index 41ef4ab3461..7f7cd761e20 100644
--- a/src/vnet/l2/l2_fib.h
+++ b/src/vnet/l2/l2_fib.h
@@ -54,9 +54,6 @@ typedef struct
   /* hash table initialized */
   u8 mac_table_initialized;
 
-  /* per swif vector of sequence number for interface based flush of MACs */
-  u8 *swif_seq_num;
-
   /* last event or ager scan duration */
   f64 evt_scan_duration;
   f64 age_scan_duration;
@@ -97,19 +94,36 @@ typedef struct
 
 STATIC_ASSERT_SIZEOF (l2fib_entry_key_t, 8);
 
+/**
+ * A combined representation of the sequence number associated
+ * with the interface and the BD.
+ * The BD is in higher bits, the interface in the lower bits, but
+ * the order is not important.
+ *
+ * It's convenient to represent this as an union of two u8s,
+ * but then in the DP one is forced to do short writes, followed
+ * by long reads, which is a sure thing for a stall
+ */
+typedef u16 l2fib_seq_num_t;
 
-typedef struct
+static_always_inline l2fib_seq_num_t
+l2_fib_mk_seq_num (u8 bd_sn, u8 if_sn)
 {
-  union
-  {
-    struct
-    {
-      u8 swif;
-      u8 bd;
-    };
-    u16 as_u16;
-  };
-} l2fib_seq_num_t;
+  return (((u16) bd_sn) << 8) | if_sn;
+}
+
+static_always_inline l2fib_seq_num_t
+l2_fib_update_seq_num (l2fib_seq_num_t sn, u8 if_sn)
+{
+  sn &= 0xff00;
+  sn |= if_sn;
+
+  return (sn);
+}
+
+extern void l2_fib_extract_seq_num (l2fib_seq_num_t sn, u8 * bd_sn,
+				    u8 * if_sn);
+extern u8 *format_l2_fib_seq_num (u8 * s, va_list * a);
 
 /**
  * Flags associated with an L2 Fib Entry
@@ -459,21 +473,6 @@ l2fib_table_dump (u32 bd_index, l2fib_entry_key_t ** l2fe_key,
 
 u8 *format_vnet_sw_if_index_name_with_NA (u8 * s, va_list * args);
 
-static_always_inline u8 *
-l2fib_swif_seq_num (u32 sw_if_index)
-{
-  l2fib_main_t *mp = &l2fib_main;
-  return vec_elt_at_index (mp->swif_seq_num, sw_if_index);
-}
-
-static_always_inline u8 *
-l2fib_valid_swif_seq_num (u32 sw_if_index)
-{
-  l2fib_main_t *mp = &l2fib_main;
-  vec_validate (mp->swif_seq_num, sw_if_index);
-  return l2fib_swif_seq_num (sw_if_index);
-}
-
 BVT (clib_bihash) * get_mac_table (void);
 
 #endif
diff --git a/src/vnet/l2/l2_fwd.c b/src/vnet/l2/l2_fwd.c
index a1674e09b77..e7accc29878 100644
--- a/src/vnet/l2/l2_fwd.c
+++ b/src/vnet/l2/l2_fwd.c
@@ -156,13 +156,12 @@ l2fwd_process (vlib_main_t * vm,
       /* check l2fib seq num for stale entries */
       if (!l2fib_entry_result_is_set_AGE_NOT (result0))
 	{
-	  l2fib_seq_num_t in_sn = {.as_u16 = vnet_buffer (b0)->l2.l2fib_sn };
-	  l2fib_seq_num_t expected_sn = {
-	    .bd = in_sn.bd,
-	    .swif = *l2fib_swif_seq_num (result0->fields.sw_if_index),
-	  };
-	  l2fib_seq_num_valid =
-	    expected_sn.as_u16 == result0->fields.sn.as_u16;
+	  l2fib_seq_num_t in_sn = vnet_buffer (b0)->l2.l2fib_sn;
+	  l2fib_seq_num_t expected_sn = l2_fib_update_seq_num (in_sn,
+							       l2_input_seq_num
+							       (result0->fields.sw_if_index));
+
+	  l2fib_seq_num_valid = expected_sn == result0->fields.sn;
 	}
 
       if (PREDICT_FALSE (!l2fib_seq_num_valid))
@@ -505,7 +504,7 @@ int_fwd (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
     }
 
   /* set the interface flag */
-  if (l2input_intf_config (sw_if_index)->xconnect)
+  if (l2input_intf_config (sw_if_index))
     {
       l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_XCONNECT, enable);
     }
diff --git a/src/vnet/l2/l2_input.c b/src/vnet/l2/l2_input.c
index 5e73faa28eb..9dc452e1558 100644
--- a/src/vnet/l2/l2_input.c
+++ b/src/vnet/l2/l2_input.c
@@ -48,8 +48,6 @@
  * For interfaces in Layer 3 mode, the packets will be routed.
  */
 
-#ifndef CLIB_MARCH_VARIANT
-
 /* Feature graph node names */
 static char *l2input_feat_names[] = {
 #define _(sym,name) name,
@@ -64,7 +62,7 @@ l2input_get_feat_names (void)
 }
 
 u8 *
-format_l2_input_features (u8 * s, va_list * args)
+format_l2_input_feature_bitmap (u8 * s, va_list * args)
 {
   static char *display_names[] = {
 #define _(sym,name) #sym,
@@ -95,394 +93,51 @@ format_l2_input_features (u8 * s, va_list * args)
     }
   return s;
 }
-#endif /* CLIB_MARCH_VARIANT */
-
-typedef struct
-{
-  /* per-pkt trace data */
-  u8 dst_and_src[12];
-  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_and_src,
-	      format_ethernet_address, t->dst_and_src + 6);
-  return s;
-}
-
-extern l2input_main_t l2input_main;
-
-#ifndef CLIB_MARCH_VARIANT
-l2input_main_t l2input_main;
-#endif /* CLIB_MARCH_VARIANT */
-
-#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)
+u8 *
+format_l2_input_features (u8 * s, va_list * args)
 {
-  /*
-   * 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_UU_FWD | L2INPUT_FEAT_GBP_FWD);
-
-      if (ethertype != ETHERNET_TYPE_ARP)
-	feat_mask &= ~(L2INPUT_FEAT_ARP_UFWD);
-
-      /* 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;
+  u32 sw_if_index = va_arg (*args, u32);
+  u32 verbose = va_arg (*args, u32);
 
-      /*
-       * 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;
+  l2_input_config_t *l2_input = l2input_intf_config (sw_if_index);
+  u32 fb = l2_input->feature_bitmap;
 
-  /* mask out features from bitmap using packet type and bd config */
-  u32 feature_bitmap = config->feature_bitmap & feat_mask;
+  /* intf input features are masked by bridge domain */
+  if (l2_input_is_bridge (l2_input))
+    fb &= l2_input->bd_feature_bitmap;
 
-  /* save for next feature graph nodes */
-  vnet_buffer (b0)->l2.feature_bitmap = feature_bitmap;
+  s =
+    format (s, "\nl2-input:\n%U", format_l2_input_feature_bitmap, fb,
+	    verbose);
 
-  /* Determine the next node */
-  *next0 = feat_bitmap_get_next_node_index (msm->feat_next_node_index,
-					    feature_bitmap);
+  return (s);
 }
 
-static_always_inline uword
-l2input_node_inline (vlib_main_t * vm,
-		     vlib_node_runtime_t * node, vlib_frame_t * frame,
-		     int do_trace)
+u8 *
+format_l2_input (u8 * s, va_list * args)
 {
-  u32 n_left_from, *from, *to_next;
-  l2input_next_t next_index;
-  l2input_main_t *msm = &l2input_main;
-  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
-
-  from = vlib_frame_vector_args (frame);
-  n_left_from = frame->n_vectors;	/* number of packets to process */
-  next_index = node->cached_next_index;
-  vlib_get_buffers (vm, from, bufs, n_left_from);
+  u32 sw_if_index = va_arg (*args, u32);
+  l2_input_config_t *l2_input = l2input_intf_config (sw_if_index);
 
-  while (n_left_from > 0)
+  /* intf input features are masked by bridge domain */
+  if (l2_input_is_bridge (l2_input))
     {
-      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);
+      bd_main_t *bdm = &bd_main;
+      u32 bd_id = l2input_main.bd_configs[l2_input->bd_index].bd_id;
 
-      while (n_left_from >= 8 && n_left_to_next >= 4)
-	{
-	  u32 next0, next1, next2, next3;
-	  u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
-
-	  /* Prefetch next iteration. */
-	  {
-
-	    /* Prefetch the buffer header and packet for the N+2 loop iteration */
-	    vlib_prefetch_buffer_header (b[4], LOAD);
-	    vlib_prefetch_buffer_header (b[5], LOAD);
-	    vlib_prefetch_buffer_header (b[6], LOAD);
-	    vlib_prefetch_buffer_header (b[7], LOAD);
-
-	    CLIB_PREFETCH (b[4]->data, CLIB_CACHE_LINE_BYTES, STORE);
-	    CLIB_PREFETCH (b[5]->data, CLIB_CACHE_LINE_BYTES, STORE);
-	    CLIB_PREFETCH (b[6]->data, CLIB_CACHE_LINE_BYTES, STORE);
-	    CLIB_PREFETCH (b[7]->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 */
-
-	  if (do_trace)
-	    {
-	      /* RX interface handles */
-	      sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
-	      sw_if_index1 = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
-	      sw_if_index2 = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
-	      sw_if_index3 = vnet_buffer (b[3])->sw_if_index[VLIB_RX];
-
-	      if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
-		{
-		  ethernet_header_t *h0 = vlib_buffer_get_current (b[0]);
-		  l2input_trace_t *t =
-		    vlib_add_trace (vm, node, b[0], sizeof (*t));
-		  t->sw_if_index = sw_if_index0;
-		  clib_memcpy_fast (t->dst_and_src, h0->dst_address,
-				    sizeof (h0->dst_address) +
-				    sizeof (h0->src_address));
-		}
-	      if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
-		{
-		  ethernet_header_t *h1 = vlib_buffer_get_current (b[1]);
-		  l2input_trace_t *t =
-		    vlib_add_trace (vm, node, b[1], sizeof (*t));
-		  t->sw_if_index = sw_if_index1;
-		  clib_memcpy_fast (t->dst_and_src, h1->dst_address,
-				    sizeof (h1->dst_address) +
-				    sizeof (h1->src_address));
-		}
-	      if (b[2]->flags & VLIB_BUFFER_IS_TRACED)
-		{
-		  ethernet_header_t *h2 = vlib_buffer_get_current (b[2]);
-		  l2input_trace_t *t =
-		    vlib_add_trace (vm, node, b[2], sizeof (*t));
-		  t->sw_if_index = sw_if_index2;
-		  clib_memcpy_fast (t->dst_and_src, h2->dst_address,
-				    sizeof (h2->dst_address) +
-				    sizeof (h2->src_address));
-		}
-	      if (b[3]->flags & VLIB_BUFFER_IS_TRACED)
-		{
-		  ethernet_header_t *h3 = vlib_buffer_get_current (b[3]);
-		  l2input_trace_t *t =
-		    vlib_add_trace (vm, node, b[3], sizeof (*t));
-		  t->sw_if_index = sw_if_index3;
-		  clib_memcpy_fast (t->dst_and_src, h3->dst_address,
-				    sizeof (h3->dst_address) +
-				    sizeof (h3->src_address));
-		}
-	    }
-
-	  classify_and_dispatch (msm, b[0], &next0);
-	  classify_and_dispatch (msm, b[1], &next1);
-	  //show the better performance when clib_memcpy_fast is put here.
-	  clib_memcpy_fast (to_next, from, sizeof (from[0]) * 4);
-	  to_next += 4;
-	  classify_and_dispatch (msm, b[2], &next2);
-	  classify_and_dispatch (msm, b[3], &next3);
-	  b += 4;
-	  n_left_from -= 4;
-	  n_left_to_next -= 4;
-
-	  /* 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,
-					   from[0], from[1], from[2], from[3],
-					   next0, next1, next2, next3);
-	  from += 4;
-	}
-
-      while (n_left_from > 0 && n_left_to_next > 0)
-	{
-	  u32 next0;
-	  u32 sw_if_index0;
-
-	  /* speculatively enqueue b0 to the current next frame */
-
-	  if (do_trace && PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
-	    {
-	      ethernet_header_t *h0 = vlib_buffer_get_current (b[0]);
-	      l2input_trace_t *t =
-		vlib_add_trace (vm, node, b[0], sizeof (*t));
-	      sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
-	      t->sw_if_index = sw_if_index0;
-	      clib_memcpy_fast (t->dst_and_src, h0->dst_address,
-				sizeof (h0->dst_address) +
-				sizeof (h0->src_address));
-	    }
-
-	  classify_and_dispatch (msm, b[0], &next0);
-	  b += 1;
-	  to_next[0] = from[0];
-	  to_next += 1;
-	  n_left_from -= 1;
-	  n_left_to_next -= 1;
-
-	  /* verify speculative enqueue, maybe switch current next frame */
-	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
-					   to_next, n_left_to_next,
-					   from[0], next0);
-	  from += 1;
-	}
-
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+      s = format (s, "  L2 bridge bd-id %d idx %d shg %d %s",
+		  bd_id, bd_find_index (bdm, bd_id), l2_input->shg,
+		  l2_input_is_bvi (l2_input) ? "bvi" : " ");
     }
+  else if (l2_input_is_xconnect (l2_input))
+    s = format (s, "  L2 xconnect %U",
+		format_vnet_sw_if_index_name, vnet_get_main (),
+		l2_input->output_sw_if_index);
 
-  vlib_node_increment_counter (vm, l2input_node.index,
-			       L2INPUT_ERROR_L2INPUT, frame->n_vectors);
-
-  return frame->n_vectors;
+  return (s);
 }
 
-VLIB_NODE_FN (l2input_node) (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) = {
-  .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* */
-
-#ifndef CLIB_MARCH_VARIANT
 clib_error_t *
 l2input_init (vlib_main_t * vm)
 {
@@ -494,10 +149,6 @@ l2input_init (vlib_main_t * vm)
   /* 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,
@@ -555,7 +206,7 @@ l2input_interface_mac_change (u32 sw_if_index,
 
   intf_config = l2input_intf_config (sw_if_index);
 
-  if (intf_config->bridge && intf_config->bvi)
+  if (l2_input_is_bridge (intf_config) && l2_input_is_bvi (intf_config))
     {
       /* delete and re-add l2fib entry for the bvi interface */
       l2fib_del_entry (old_address, intf_config->bd_index, sw_if_index);
@@ -567,6 +218,32 @@ l2input_interface_mac_change (u32 sw_if_index,
     }
 }
 
+walk_rc_t
+l2input_recache (u32 bd_index, u32 sw_if_index)
+{
+  l2_input_config_t *input;
+  l2_bridge_domain_t *bd;
+
+  bd = bd_get (bd_index);
+  input = l2input_intf_config (sw_if_index);
+
+  input->bd_mac_age = bd->mac_age;
+  input->bd_seq_num = bd->seq_num;
+  input->bd_feature_bitmap = bd->feature_bitmap;
+
+  return (WALK_CONTINUE);
+}
+
+void
+l2_input_seq_num_inc (u32 sw_if_index)
+{
+  l2_input_config_t *input;
+
+  input = vec_elt_at_index (l2input_main.configs, sw_if_index);
+
+  input->seq_num++;
+}
+
 /**
  * Set the subinterface to run in l2 or l3 mode.
  * For L3 mode, just the sw_if_index is specified.
@@ -584,7 +261,6 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 		 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;
@@ -600,10 +276,10 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
   if (l2fib_main.mac_table_initialized == 0)
     l2fib_table_init ();
 
-  if (config->bridge)
+  if (l2_input_is_bridge (config))
     {
       /* Interface is already in bridge mode. Undo the existing config. */
-      bd_config = vec_elt_at_index (mp->bd_configs, config->bd_index);
+      bd_config = bd_get (config->bd_index);
 
       /* remove interface from flood vector */
       bd_remove_member (bd_config, sw_if_index);
@@ -614,7 +290,7 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 	  vnet_sw_interface_t *si;
 
 	  bd_config->bvi_sw_if_index = ~0;
-	  config->bvi = 0;
+	  config->flags &= ~L2_INPUT_FLAG_BVI;
 
 	  /* delete the l2fib entry for the bvi interface */
 	  l2fib_del_entry (hi->hw_address, config->bd_index, sw_if_index);
@@ -634,9 +310,10 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 	  (bd_config->feature_bitmap & L2INPUT_FEAT_LEARN))
 	l2fib_flush_int_mac (vm, sw_if_index);
 
+      bd_input_walk (config->bd_index, l2input_recache, NULL);
       l2_if_adjust--;
     }
-  else if (config->xconnect)
+  else if (l2_input_is_xconnect (config))
     {
       l2_if_adjust--;
     }
@@ -650,8 +327,7 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
     {
       /* 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->flags = L2_INPUT_FLAG_NONE;
       config->shg = 0;
       config->bd_index = 0;
       config->feature_bitmap = L2INPUT_FEAT_DROP;
@@ -684,10 +360,9 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 	  if (!hi)
 	    return MODE_ERROR_ETH;	/* non-ethernet */
 
-	  config->xconnect = 0;
-	  config->bridge = 1;
+	  config->flags = L2_INPUT_FLAG_BRIDGE;
 	  config->bd_index = bd_index;
-	  *l2fib_valid_swif_seq_num (sw_if_index) += 1;
+	  l2_input_seq_num_inc (sw_if_index);
 
 	  /*
 	   * Enable forwarding, flooding, learning and ARP termination by default
@@ -724,7 +399,7 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 		  return MODE_ERROR_BVI_DEF;	/* bd already has a bvi interface */
 		}
 	      bd_config->bvi_sw_if_index = sw_if_index;
-	      config->bvi = 1;
+	      config->flags |= L2_INPUT_FLAG_BVI;
 
 	      /* create the l2fib entry for the bvi interface */
 	      l2fib_add_entry (hi->hw_address, bd_index, sw_if_index,
@@ -763,8 +438,7 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 	}
       else if (mode == MODE_L2_XC)
 	{
-	  config->xconnect = 1;
-	  config->bridge = 0;
+	  config->flags = L2_INPUT_FLAG_XCONNECT;
 	  config->output_sw_if_index = xc_sw_if_index;
 
 	  /* Make sure last-chance drop is configured */
@@ -779,8 +453,7 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 	}
       else if (mode == MODE_L2_CLASSIFY)
 	{
-	  config->xconnect = 1;
-	  config->bridge = 0;
+	  config->flags = L2_INPUT_FLAG_XCONNECT;
 	  config->output_sw_if_index = xc_sw_if_index;
 
 	  /* Make sure last-chance drop is configured */
@@ -806,6 +479,8 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
        */
 
       l2_if_adjust++;
+
+      bd_input_walk (bd_index, l2input_recache, NULL);
     }
 
   /* Adjust count of L2 interfaces */
@@ -841,7 +516,31 @@ set_int_l2_mode (vlib_main_t * vm, vnet_main_t * vnet_main,	/*           */
 
   return 0;
 }
-#endif /* CLIB_MARCH_VARIANT */
+
+static clib_error_t *
+l2_input_interface_add_del (vnet_main_t * vnm, u32 sw_if_index, u32 is_add)
+{
+  if (!is_add)
+    {
+      vlib_main_t *vm = vlib_get_main ();
+      l2_input_config_t *config;
+
+      if (sw_if_index < vec_len (l2input_main.configs))
+	{
+	  config = vec_elt_at_index (l2input_main.configs, sw_if_index);
+	  if (l2_input_is_xconnect (config))
+	    set_int_l2_mode (vm, vnm, MODE_L3, config->output_sw_if_index, 0,
+			     L2_BD_PORT_TYPE_NORMAL, 0, 0);
+	  if (l2_input_is_xconnect (config) || l2_input_is_bridge (config))
+	    set_int_l2_mode (vm, vnm, MODE_L3, sw_if_index, 0,
+			     L2_BD_PORT_TYPE_NORMAL, 0, 0);
+	}
+    }
+
+  return (NULL);
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION (l2_input_interface_add_del);
 
 /**
  * Set subinterface in bridging mode with a bridge-domain ID.
@@ -1119,16 +818,16 @@ show_int_mode (vlib_main_t * vm,
   vec_foreach (si, sis)
   {
     l2_input_config_t *config = l2input_intf_config (si->sw_if_index);
-    if (config->bridge)
+    if (l2_input_is_bridge (config))
       {
 	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);
+	args = format (0, "bd_id %d%s shg %d", bd_id,
+		       l2_input_is_bvi (config) ? " bvi" : "", config->shg);
       }
-    else if (config->xconnect)
+    else if (l2_input_is_xconnect (config))
       {
 	mode = "l2 xconnect";
 	args = format (0, "%U",
@@ -1204,7 +903,6 @@ _(l2output_init)				\
 _(l2_patch_init)				\
 _(l2_xcrw_init)
 
-#ifndef CLIB_MARCH_VARIANT
 clib_error_t *
 l2_init (vlib_main_t * vm)
 {
@@ -1219,7 +917,6 @@ while (0);
 }
 
 VLIB_INIT_FUNCTION (l2_init);
-#endif /* CLIB_MARCH_VARIANT */
 
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/vnet/l2/l2_input.h b/src/vnet/l2/l2_input.h
index 0e1e98f883d..9a59d3521d0 100644
--- a/src/vnet/l2/l2_input.h
+++ b/src/vnet/l2/l2_input.h
@@ -25,32 +25,57 @@
 #include <vnet/ethernet/packet.h>
 #include <vnet/ip/ip.h>
 
-/* Per-subinterface L2 feature configuration */
+/* l2 connection type */
+typedef enum l2_input_flags_t_
+{
+  /* NONE imples L3 mode. */
+  L2_INPUT_FLAG_NONE = 0,
+  L2_INPUT_FLAG_XCONNECT = (1 << 0),
+  L2_INPUT_FLAG_BRIDGE = (1 << 1),
+  L2_INPUT_FLAG_BVI = (1 << 2),
+} __clib_packed l2_input_flags_t;
 
+/* Per-subinterface L2 feature configuration */
 typedef struct
 {
+  u8 __force_u64_alignement[0] __attribute__ ((aligned (8)));
 
   union
   {
-    u16 bd_index;		/* bridge domain id */
-    u32 output_sw_if_index;	/* for xconnect */
+    /* bridge domain id and values cached from the BD */
+    struct
+    {
+      u16 bd_index;
+      u8 bd_seq_num;
+      u8 bd_mac_age;
+    };
+    /* for xconnect */
+    u32 output_sw_if_index;
   };
 
   /* config for which input features are configured on this interface */
   u32 feature_bitmap;
 
+  /* config for which input features are configured on this interface's
+   * BD - this is cahced from the BD struct*/
+  u32 bd_feature_bitmap;
+
   /* split horizon group */
   u8 shg;
 
-  /* Interface mode. If both are 0, this interface is in L3 mode */
-  u8 xconnect;
-  u8 bridge;
+  /* Interface sequence number */
+  u8 seq_num;
 
-  /* this is the bvi interface for the bridge-domain */
-  u8 bvi;
+  /* Flags describing this interface */
+  l2_input_flags_t flags;
 
+  /* A wee bit of spare space */
+  u8 __pad;
 } l2_input_config_t;
 
+/* Ensure a struct is an even multiple of 8 bytes,
+ * so they do not stradle cache lines */
+STATIC_ASSERT_SIZEOF (l2_input_config_t, 2 * sizeof (u64));
 
 typedef struct
 {
@@ -157,7 +182,9 @@ STATIC_ASSERT ((u64) L2INPUT_VALID_MASK == (1ull << L2INPUT_N_FEAT) - 1, "");
 char **l2input_get_feat_names (void);
 
 /* arg0 - u32 feature_bitmap, arg1 - u32 verbose */
+u8 *format_l2_input_feature_bitmap (u8 * s, va_list * args);
 u8 *format_l2_input_features (u8 * s, va_list * args);
+u8 *format_l2_input (u8 * s, va_list * args);
 
 static_always_inline u8
 bd_feature_flood (l2_bridge_domain_t * bd_config)
@@ -200,6 +227,35 @@ bd_feature_arp_ufwd (l2_bridge_domain_t * bd_config)
 	  L2INPUT_FEAT_ARP_UFWD);
 }
 
+static inline bool
+l2_input_is_bridge (const l2_input_config_t * input)
+{
+  return (input->flags & L2_INPUT_FLAG_BRIDGE);
+}
+
+static inline bool
+l2_input_is_xconnect (const l2_input_config_t * input)
+{
+  return (input->flags & L2_INPUT_FLAG_XCONNECT);
+}
+
+static inline bool
+l2_input_is_bvi (const l2_input_config_t * input)
+{
+  return (input->flags & L2_INPUT_FLAG_BVI);
+}
+
+static_always_inline u8
+l2_input_seq_num (u32 sw_if_index)
+{
+  l2_input_config_t *input;
+
+  input = vec_elt_at_index (l2input_main.configs, sw_if_index);
+
+  return input->seq_num;
+}
+
+
 /** Masks for eliminating features that do not apply to a packet */
 
 /** Get a pointer to the config for the given interface */
@@ -217,6 +273,9 @@ void l2input_interface_mac_change (u32 sw_if_index,
 				   const u8 * old_address,
 				   const u8 * new_address);
 
+void l2_input_seq_num_inc (u32 sw_if_index);
+walk_rc_t l2input_recache (u32 bd_index, u32 sw_if_index);
+
 #define MODE_L3        0
 #define MODE_L2_BRIDGE 1
 #define MODE_L2_XC     2
diff --git a/src/vnet/l2/l2_input_node.c b/src/vnet/l2/l2_input_node.c
new file mode 100644
index 00000000000..898e16ab347
--- /dev/null
+++ b/src/vnet/l2/l2_input_node.c
@@ -0,0 +1,401 @@
+/*
+ * 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.
+ */
+
+typedef struct
+{
+  /* per-pkt trace data */
+  u8 dst_and_src[12];
+  u32 next_index;
+  u32 sw_if_index;
+  u32 feat_mask;
+} 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 [%U]",
+	      t->sw_if_index,
+	      format_ethernet_address, t->dst_and_src,
+	      format_ethernet_address, t->dst_and_src + 6,
+	      format_l2_input_feature_bitmap, t->feat_mask, 0);
+  return s;
+}
+
+extern l2input_main_t l2input_main;
+
+#ifndef CLIB_MARCH_VARIANT
+l2input_main_t l2input_main;
+#endif /* CLIB_MARCH_VARIANT */
+
+#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, u16 * 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_UU_FWD | L2INPUT_FEAT_GBP_FWD);
+
+      if (ethertype != ETHERNET_TYPE_ARP)
+	feat_mask &= ~(L2INPUT_FEAT_ARP_UFWD);
+
+      /* 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 (l2_input_is_bridge (config))
+    {
+      /* Do bridge-domain processing */
+      /* save BD ID for next feature graph nodes */
+      vnet_buffer (b0)->l2.bd_index = config->bd_index;
+
+      /* Save bridge domain and interface seq_num */
+      vnet_buffer (b0)->l2.l2fib_sn = l2_fib_mk_seq_num
+	(config->bd_seq_num, config->seq_num);
+      vnet_buffer (b0)->l2.bd_age = config->bd_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 & config->bd_feature_bitmap;
+    }
+  else if (l2_input_is_xconnect (config))
+    {
+      /* 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;
+  l2input_next_t next_index;
+  l2input_main_t *msm = &l2input_main;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
+  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
+
+  from = vlib_frame_vector_args (frame);
+  n_left = frame->n_vectors;	/* number of packets to process */
+  next_index = node->cached_next_index;
+
+  vlib_get_buffers (vm, from, bufs, n_left);
+
+  while (n_left > 0)
+    {
+      while (n_left >= 8)
+	{
+	  u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
+
+	  /* Prefetch next iteration. */
+	  {
+	    /* Prefetch the buffer header and packet for the N+2 loop iteration */
+	    vlib_prefetch_buffer_header (b[4], LOAD);
+	    vlib_prefetch_buffer_header (b[5], LOAD);
+	    vlib_prefetch_buffer_header (b[6], LOAD);
+	    vlib_prefetch_buffer_header (b[7], LOAD);
+
+	    CLIB_PREFETCH (b[4]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (b[5]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (b[6]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (b[7]->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  }
+
+	  classify_and_dispatch (msm, b[0], &next[0]);
+	  classify_and_dispatch (msm, b[1], &next[1]);
+	  classify_and_dispatch (msm, b[2], &next[2]);
+	  classify_and_dispatch (msm, b[3], &next[3]);
+
+	  if (do_trace)
+	    {
+	      /* RX interface handles */
+	      sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	      sw_if_index1 = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
+	      sw_if_index2 = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
+	      sw_if_index3 = vnet_buffer (b[3])->sw_if_index[VLIB_RX];
+
+	      if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  ethernet_header_t *h0 = vlib_buffer_get_current (b[0]);
+		  l2input_trace_t *t =
+		    vlib_add_trace (vm, node, b[0], sizeof (*t));
+		  t->sw_if_index = sw_if_index0;
+		  t->feat_mask = vnet_buffer (b[0])->l2.feature_bitmap;
+		  clib_memcpy_fast (t->dst_and_src, h0->dst_address,
+				    sizeof (h0->dst_address) +
+				    sizeof (h0->src_address));
+		}
+	      if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  ethernet_header_t *h1 = vlib_buffer_get_current (b[1]);
+		  l2input_trace_t *t =
+		    vlib_add_trace (vm, node, b[1], sizeof (*t));
+		  t->sw_if_index = sw_if_index1;
+		  t->feat_mask = vnet_buffer (b[1])->l2.feature_bitmap;
+		  clib_memcpy_fast (t->dst_and_src, h1->dst_address,
+				    sizeof (h1->dst_address) +
+				    sizeof (h1->src_address));
+		}
+	      if (b[2]->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  ethernet_header_t *h2 = vlib_buffer_get_current (b[2]);
+		  l2input_trace_t *t =
+		    vlib_add_trace (vm, node, b[2], sizeof (*t));
+		  t->sw_if_index = sw_if_index2;
+		  t->feat_mask = vnet_buffer (b[2])->l2.feature_bitmap;
+		  clib_memcpy_fast (t->dst_and_src, h2->dst_address,
+				    sizeof (h2->dst_address) +
+				    sizeof (h2->src_address));
+		}
+	      if (b[3]->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  ethernet_header_t *h3 = vlib_buffer_get_current (b[3]);
+		  l2input_trace_t *t =
+		    vlib_add_trace (vm, node, b[3], sizeof (*t));
+		  t->sw_if_index = sw_if_index3;
+		  t->feat_mask = vnet_buffer (b[3])->l2.feature_bitmap;
+		  clib_memcpy_fast (t->dst_and_src, h3->dst_address,
+				    sizeof (h3->dst_address) +
+				    sizeof (h3->src_address));
+		}
+	    }
+
+	  b += 4;
+	  n_left -= 4;
+	  next += 4;
+	}
+
+      while (n_left > 0)
+	{
+	  classify_and_dispatch (msm, b[0], &next[0]);
+
+	  if (do_trace && PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      ethernet_header_t *h0 = vlib_buffer_get_current (b[0]);
+	      l2input_trace_t *t =
+		vlib_add_trace (vm, node, b[0], sizeof (*t));
+	      t->sw_if_index = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
+	      t->feat_mask = vnet_buffer (b[0])->l2.feature_bitmap;
+	      clib_memcpy_fast (t->dst_and_src, h0->dst_address,
+				sizeof (h0->dst_address) +
+				sizeof (h0->src_address));
+	    }
+
+	  b += 1;
+	  next += 1;
+	  n_left -= 1;
+	}
+    }
+
+  vlib_node_increment_counter (vm, l2input_node.index,
+			       L2INPUT_ERROR_L2INPUT, frame->n_vectors);
+
+  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
+
+  return frame->n_vectors;
+}
+
+VLIB_NODE_FN (l2input_node) (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) = {
+  .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* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/l2/l2_learn.c b/src/vnet/l2/l2_learn.c
index 3f5b48bfa99..6f2201b3ade 100644
--- a/src/vnet/l2/l2_learn.c
+++ b/src/vnet/l2/l2_learn.c
@@ -128,7 +128,7 @@ l2learn_process (vlib_node_runtime_t * node,
     {
       /* Entry in L2FIB with matching sw_if_index matched - normal fast path */
       u32 dtime = timestamp - result0->fields.timestamp;
-      u32 dsn = result0->fields.sn.as_u16 - vnet_buffer (b0)->l2.l2fib_sn;
+      u32 dsn = (result0->fields.sn - vnet_buffer (b0)->l2.l2fib_sn);
       u32 check = (dtime && vnet_buffer (b0)->l2.bd_age) || dsn;
 
       if (PREDICT_TRUE (check == 0))
@@ -224,7 +224,7 @@ l2learn_process (vlib_node_runtime_t * node,
 
   /* Update the entry */
   result0->fields.timestamp = timestamp;
-  result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
+  result0->fields.sn = vnet_buffer (b0)->l2.l2fib_sn;
 
   BVT (clib_bihash_kv) kv;
   kv.key = key0->raw;