Reorganize source tree to use single autotools instance

Change-Id: I7b51f88292e057c6443b12224486f2d0c9f8ae23
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 3345 insertions, 0 deletions

diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
new file mode 100644
index 00000000000..6e91b9e91e1
--- /dev/null
+++ b/src/vnet/ip/ip4_forward.c
@@ -0,0 +1,3345 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+ * ip/ip4_forward.c: IP v4 forwarding
+ *
+ * Copyright (c) 2008 Eliot Dresselhaus
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vnet/ethernet/ethernet.h>	/* for ethernet_header_t */
+#include <vnet/ethernet/arp_packet.h>	/* for ethernet_arp_header_t */
+#include <vnet/ppp/ppp.h>
+#include <vnet/srp/srp.h>	/* for srp_hw_interface_class */
+#include <vnet/api_errno.h>	/* for API error numbers */
+#include <vnet/fib/fib_table.h>	/* for FIB table and entry creation */
+#include <vnet/fib/fib_entry.h>	/* for FIB table and entry creation */
+#include <vnet/fib/fib_urpf_list.h>	/* for FIB uRPF check */
+#include <vnet/fib/ip4_fib.h>
+#include <vnet/dpo/load_balance.h>
+#include <vnet/dpo/classify_dpo.h>
+
+/**
+ * @file
+ * @brief IPv4 Forwarding.
+ *
+ * This file contains the source code for IPv4 forwarding.
+ */
+
+void
+ip4_forward_next_trace (vlib_main_t * vm,
+			vlib_node_runtime_t * node,
+			vlib_frame_t * frame,
+			vlib_rx_or_tx_t which_adj_index);
+
+always_inline uword
+ip4_lookup_inline (vlib_main_t * vm,
+		   vlib_node_runtime_t * node,
+		   vlib_frame_t * frame,
+		   int lookup_for_responses_to_locally_received_packets)
+{
+  ip4_main_t *im = &ip4_main;
+  vlib_combined_counter_main_t *cm = &load_balance_main.lbm_to_counters;
+  u32 n_left_from, n_left_to_next, *from, *to_next;
+  ip_lookup_next_t next;
+  u32 cpu_index = os_get_cpu_number ();
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
+
+      while (n_left_from >= 8 && n_left_to_next >= 4)
+	{
+	  vlib_buffer_t *p0, *p1, *p2, *p3;
+	  ip4_header_t *ip0, *ip1, *ip2, *ip3;
+	  __attribute__ ((unused)) tcp_header_t *tcp0, *tcp1, *tcp2, *tcp3;
+	  ip_lookup_next_t next0, next1, next2, next3;
+	  const load_balance_t *lb0, *lb1, *lb2, *lb3;
+	  ip4_fib_mtrie_t *mtrie0, *mtrie1, *mtrie2, *mtrie3;
+	  ip4_fib_mtrie_leaf_t leaf0, leaf1, leaf2, leaf3;
+	  ip4_address_t *dst_addr0, *dst_addr1, *dst_addr2, *dst_addr3;
+	  __attribute__ ((unused)) u32 pi0, fib_index0, lb_index0,
+	    is_tcp_udp0;
+	  __attribute__ ((unused)) u32 pi1, fib_index1, lb_index1,
+	    is_tcp_udp1;
+	  __attribute__ ((unused)) u32 pi2, fib_index2, lb_index2,
+	    is_tcp_udp2;
+	  __attribute__ ((unused)) u32 pi3, fib_index3, lb_index3,
+	    is_tcp_udp3;
+	  flow_hash_config_t flow_hash_config0, flow_hash_config1;
+	  flow_hash_config_t flow_hash_config2, flow_hash_config3;
+	  u32 hash_c0, hash_c1, hash_c2, hash_c3;
+	  const dpo_id_t *dpo0, *dpo1, *dpo2, *dpo3;
+
+	  /* 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]);
+
+	    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, sizeof (ip0[0]), LOAD);
+	    CLIB_PREFETCH (p5->data, sizeof (ip0[0]), LOAD);
+	    CLIB_PREFETCH (p6->data, sizeof (ip0[0]), LOAD);
+	    CLIB_PREFETCH (p7->data, sizeof (ip0[0]), LOAD);
+	  }
+
+	  pi0 = to_next[0] = from[0];
+	  pi1 = to_next[1] = from[1];
+	  pi2 = to_next[2] = from[2];
+	  pi3 = to_next[3] = from[3];
+
+	  from += 4;
+	  to_next += 4;
+	  n_left_to_next -= 4;
+	  n_left_from -= 4;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  p1 = vlib_get_buffer (vm, pi1);
+	  p2 = vlib_get_buffer (vm, pi2);
+	  p3 = vlib_get_buffer (vm, pi3);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  ip1 = vlib_buffer_get_current (p1);
+	  ip2 = vlib_buffer_get_current (p2);
+	  ip3 = vlib_buffer_get_current (p3);
+
+	  dst_addr0 = &ip0->dst_address;
+	  dst_addr1 = &ip1->dst_address;
+	  dst_addr2 = &ip2->dst_address;
+	  dst_addr3 = &ip3->dst_address;
+
+	  fib_index0 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index1 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p1)->sw_if_index[VLIB_RX]);
+	  fib_index2 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p2)->sw_if_index[VLIB_RX]);
+	  fib_index3 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p3)->sw_if_index[VLIB_RX]);
+	  fib_index0 =
+	    (vnet_buffer (p0)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+	  fib_index1 =
+	    (vnet_buffer (p1)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index1 : vnet_buffer (p1)->sw_if_index[VLIB_TX];
+	  fib_index2 =
+	    (vnet_buffer (p2)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index2 : vnet_buffer (p2)->sw_if_index[VLIB_TX];
+	  fib_index3 =
+	    (vnet_buffer (p3)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index3 : vnet_buffer (p3)->sw_if_index[VLIB_TX];
+
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    {
+	      mtrie0 = &ip4_fib_get (fib_index0)->mtrie;
+	      mtrie1 = &ip4_fib_get (fib_index1)->mtrie;
+	      mtrie2 = &ip4_fib_get (fib_index2)->mtrie;
+	      mtrie3 = &ip4_fib_get (fib_index3)->mtrie;
+
+	      leaf0 = leaf1 = leaf2 = leaf3 = IP4_FIB_MTRIE_LEAF_ROOT;
+
+	      leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 0);
+	      leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 0);
+	      leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 0);
+	      leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 0);
+	    }
+
+	  tcp0 = (void *) (ip0 + 1);
+	  tcp1 = (void *) (ip1 + 1);
+	  tcp2 = (void *) (ip2 + 1);
+	  tcp3 = (void *) (ip3 + 1);
+
+	  is_tcp_udp0 = (ip0->protocol == IP_PROTOCOL_TCP
+			 || ip0->protocol == IP_PROTOCOL_UDP);
+	  is_tcp_udp1 = (ip1->protocol == IP_PROTOCOL_TCP
+			 || ip1->protocol == IP_PROTOCOL_UDP);
+	  is_tcp_udp2 = (ip2->protocol == IP_PROTOCOL_TCP
+			 || ip2->protocol == IP_PROTOCOL_UDP);
+	  is_tcp_udp3 = (ip1->protocol == IP_PROTOCOL_TCP
+			 || ip1->protocol == IP_PROTOCOL_UDP);
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    {
+	      leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 1);
+	      leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 1);
+	      leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 1);
+	      leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 1);
+	    }
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    {
+	      leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 2);
+	      leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 2);
+	      leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 2);
+	      leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 2);
+	    }
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    {
+	      leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 3);
+	      leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 3);
+	      leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 3);
+	      leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 3);
+	    }
+
+	  if (lookup_for_responses_to_locally_received_packets)
+	    {
+	      lb_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_RX];
+	      lb_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_RX];
+	      lb_index2 = vnet_buffer (p2)->ip.adj_index[VLIB_RX];
+	      lb_index3 = vnet_buffer (p3)->ip.adj_index[VLIB_RX];
+	    }
+	  else
+	    {
+	      /* Handle default route. */
+	      leaf0 =
+		(leaf0 ==
+		 IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie0->default_leaf : leaf0);
+	      leaf1 =
+		(leaf1 ==
+		 IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie1->default_leaf : leaf1);
+	      leaf2 =
+		(leaf2 ==
+		 IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie2->default_leaf : leaf2);
+	      leaf3 =
+		(leaf3 ==
+		 IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie3->default_leaf : leaf3);
+	      lb_index0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
+	      lb_index1 = ip4_fib_mtrie_leaf_get_adj_index (leaf1);
+	      lb_index2 = ip4_fib_mtrie_leaf_get_adj_index (leaf2);
+	      lb_index3 = ip4_fib_mtrie_leaf_get_adj_index (leaf3);
+	    }
+
+	  lb0 = load_balance_get (lb_index0);
+	  lb1 = load_balance_get (lb_index1);
+	  lb2 = load_balance_get (lb_index2);
+	  lb3 = load_balance_get (lb_index3);
+
+	  /* Use flow hash to compute multipath adjacency. */
+	  hash_c0 = vnet_buffer (p0)->ip.flow_hash = 0;
+	  hash_c1 = vnet_buffer (p1)->ip.flow_hash = 0;
+	  hash_c2 = vnet_buffer (p2)->ip.flow_hash = 0;
+	  hash_c3 = vnet_buffer (p3)->ip.flow_hash = 0;
+	  if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
+	    {
+	      flow_hash_config0 = lb0->lb_hash_config;
+	      hash_c0 = vnet_buffer (p0)->ip.flow_hash =
+		ip4_compute_flow_hash (ip0, flow_hash_config0);
+	    }
+	  if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
+	    {
+	      flow_hash_config1 = lb1->lb_hash_config;
+	      hash_c1 = vnet_buffer (p1)->ip.flow_hash =
+		ip4_compute_flow_hash (ip1, flow_hash_config1);
+	    }
+	  if (PREDICT_FALSE (lb2->lb_n_buckets > 1))
+	    {
+	      flow_hash_config2 = lb2->lb_hash_config;
+	      hash_c2 = vnet_buffer (p2)->ip.flow_hash =
+		ip4_compute_flow_hash (ip2, flow_hash_config2);
+	    }
+	  if (PREDICT_FALSE (lb3->lb_n_buckets > 1))
+	    {
+	      flow_hash_config3 = lb3->lb_hash_config;
+	      hash_c3 = vnet_buffer (p3)->ip.flow_hash =
+		ip4_compute_flow_hash (ip3, flow_hash_config3);
+	    }
+
+	  ASSERT (lb0->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb0->lb_n_buckets));
+	  ASSERT (lb1->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb1->lb_n_buckets));
+	  ASSERT (lb2->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb2->lb_n_buckets));
+	  ASSERT (lb3->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb3->lb_n_buckets));
+
+	  dpo0 = load_balance_get_bucket_i (lb0,
+					    (hash_c0 &
+					     (lb0->lb_n_buckets_minus_1)));
+	  dpo1 = load_balance_get_bucket_i (lb1,
+					    (hash_c1 &
+					     (lb1->lb_n_buckets_minus_1)));
+	  dpo2 = load_balance_get_bucket_i (lb2,
+					    (hash_c2 &
+					     (lb2->lb_n_buckets_minus_1)));
+	  dpo3 = load_balance_get_bucket_i (lb3,
+					    (hash_c3 &
+					     (lb3->lb_n_buckets_minus_1)));
+
+	  next0 = dpo0->dpoi_next_node;
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+	  next1 = dpo1->dpoi_next_node;
+	  vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
+	  next2 = dpo2->dpoi_next_node;
+	  vnet_buffer (p2)->ip.adj_index[VLIB_TX] = dpo2->dpoi_index;
+	  next3 = dpo3->dpoi_next_node;
+	  vnet_buffer (p3)->ip.adj_index[VLIB_TX] = dpo3->dpoi_index;
+
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lb_index0, 1,
+	     vlib_buffer_length_in_chain (vm, p0)
+	     + sizeof (ethernet_header_t));
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lb_index1, 1,
+	     vlib_buffer_length_in_chain (vm, p1)
+	     + sizeof (ethernet_header_t));
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lb_index2, 1,
+	     vlib_buffer_length_in_chain (vm, p2)
+	     + sizeof (ethernet_header_t));
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lb_index3, 1,
+	     vlib_buffer_length_in_chain (vm, p3)
+	     + sizeof (ethernet_header_t));
+
+	  vlib_validate_buffer_enqueue_x4 (vm, node, next,
+					   to_next, n_left_to_next,
+					   pi0, pi1, pi2, pi3,
+					   next0, next1, next2, next3);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *p0;
+	  ip4_header_t *ip0;
+	  __attribute__ ((unused)) tcp_header_t *tcp0;
+	  ip_lookup_next_t next0;
+	  const load_balance_t *lb0;
+	  ip4_fib_mtrie_t *mtrie0;
+	  ip4_fib_mtrie_leaf_t leaf0;
+	  ip4_address_t *dst_addr0;
+	  __attribute__ ((unused)) u32 pi0, fib_index0, is_tcp_udp0, lbi0;
+	  flow_hash_config_t flow_hash_config0;
+	  const dpo_id_t *dpo0;
+	  u32 hash_c0;
+
+	  pi0 = from[0];
+	  to_next[0] = pi0;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  dst_addr0 = &ip0->dst_address;
+
+	  fib_index0 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index0 =
+	    (vnet_buffer (p0)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    {
+	      mtrie0 = &ip4_fib_get (fib_index0)->mtrie;
+
+	      leaf0 = IP4_FIB_MTRIE_LEAF_ROOT;
+
+	      leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 0);
+	    }
+
+	  tcp0 = (void *) (ip0 + 1);
+
+	  is_tcp_udp0 = (ip0->protocol == IP_PROTOCOL_TCP
+			 || ip0->protocol == IP_PROTOCOL_UDP);
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 1);
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 2);
+
+	  if (!lookup_for_responses_to_locally_received_packets)
+	    leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 3);
+
+	  if (lookup_for_responses_to_locally_received_packets)
+	    lbi0 = vnet_buffer (p0)->ip.adj_index[VLIB_RX];
+	  else
+	    {
+	      /* Handle default route. */
+	      leaf0 =
+		(leaf0 ==
+		 IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie0->default_leaf : leaf0);
+	      lbi0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
+	    }
+
+	  lb0 = load_balance_get (lbi0);
+
+	  /* Use flow hash to compute multipath adjacency. */
+	  hash_c0 = vnet_buffer (p0)->ip.flow_hash = 0;
+	  if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
+	    {
+	      flow_hash_config0 = lb0->lb_hash_config;
+
+	      hash_c0 = vnet_buffer (p0)->ip.flow_hash =
+		ip4_compute_flow_hash (ip0, flow_hash_config0);
+	    }
+
+	  ASSERT (lb0->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb0->lb_n_buckets));
+
+	  dpo0 = load_balance_get_bucket_i (lb0,
+					    (hash_c0 &
+					     (lb0->lb_n_buckets_minus_1)));
+
+	  next0 = dpo0->dpoi_next_node;
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lbi0, 1, vlib_buffer_length_in_chain (vm, p0));
+
+	  from += 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+	  n_left_from -= 1;
+
+	  if (PREDICT_FALSE (next0 != next))
+	    {
+	      n_left_to_next += 1;
+	      vlib_put_next_frame (vm, node, next, n_left_to_next);
+	      next = next0;
+	      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
+	      to_next[0] = pi0;
+	      to_next += 1;
+	      n_left_to_next -= 1;
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, next, n_left_to_next);
+    }
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  return frame->n_vectors;
+}
+
+/** @brief IPv4 lookup node.
+    @node ip4-lookup
+
+    This is the main IPv4 lookup dispatch node.
+
+    @param vm vlib_main_t corresponding to the current thread
+    @param node vlib_node_runtime_t
+    @param frame vlib_frame_t whose contents should be dispatched
+
+    @par Graph mechanics: buffer metadata, next index usage
+
+    @em Uses:
+    - <code>vnet_buffer(b)->sw_if_index[VLIB_RX]</code>
+        - Indicates the @c sw_if_index value of the interface that the
+	  packet was received on.
+    - <code>vnet_buffer(b)->sw_if_index[VLIB_TX]</code>
+        - When the value is @c ~0 then the node performs a longest prefix
+          match (LPM) for the packet destination address in the FIB attached
+          to the receive interface.
+        - Otherwise perform LPM for the packet destination address in the
+          indicated FIB. In this case <code>[VLIB_TX]</code> is a FIB index
+          value (0, 1, ...) and not a VRF id.
+
+    @em Sets:
+    - <code>vnet_buffer(b)->ip.adj_index[VLIB_TX]</code>
+        - The lookup result adjacency index.
+
+    <em>Next Index:</em>
+    - Dispatches the packet to the node index found in
+      ip_adjacency_t @c adj->lookup_next_index
+      (where @c adj is the lookup result adjacency).
+*/
+static uword
+ip4_lookup (vlib_main_t * vm,
+	    vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return ip4_lookup_inline (vm, node, frame,
+			    /* lookup_for_responses_to_locally_received_packets */
+			    0);
+
+}
+
+static u8 *format_ip4_lookup_trace (u8 * s, va_list * args);
+
+VLIB_REGISTER_NODE (ip4_lookup_node) =
+{
+.function = ip4_lookup,.name = "ip4-lookup",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_lookup_trace,.n_next_nodes =
+    IP_LOOKUP_N_NEXT,.next_nodes = IP4_LOOKUP_NEXT_NODES,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_lookup_node, ip4_lookup);
+
+always_inline uword
+ip4_load_balance (vlib_main_t * vm,
+		  vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  vlib_combined_counter_main_t *cm = &load_balance_main.lbm_via_counters;
+  u32 n_left_from, n_left_to_next, *from, *to_next;
+  ip_lookup_next_t next;
+  u32 cpu_index = os_get_cpu_number ();
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next = node->cached_next_index;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
+
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  ip_lookup_next_t next0, next1;
+	  const load_balance_t *lb0, *lb1;
+	  vlib_buffer_t *p0, *p1;
+	  u32 pi0, lbi0, hc0, pi1, lbi1, hc1;
+	  const ip4_header_t *ip0, *ip1;
+	  const dpo_id_t *dpo0, *dpo1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, STORE);
+	    vlib_prefetch_buffer_header (p3, STORE);
+
+	    CLIB_PREFETCH (p2->data, sizeof (ip0[0]), STORE);
+	    CLIB_PREFETCH (p3->data, sizeof (ip0[0]), STORE);
+	  }
+
+	  pi0 = to_next[0] = from[0];
+	  pi1 = to_next[1] = from[1];
+
+	  from += 2;
+	  n_left_from -= 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  p1 = vlib_get_buffer (vm, pi1);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  ip1 = vlib_buffer_get_current (p1);
+	  lbi0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+	  lbi1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];
+
+	  lb0 = load_balance_get (lbi0);
+	  lb1 = load_balance_get (lbi1);
+
+	  /*
+	   * this node is for via FIBs we can re-use the hash value from the
+	   * to node if present.
+	   * We don't want to use the same hash value at each level in the recursion
+	   * graph as that would lead to polarisation
+	   */
+	  hc0 = vnet_buffer (p0)->ip.flow_hash = 0;
+	  hc1 = vnet_buffer (p1)->ip.flow_hash = 0;
+
+	  if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
+	    {
+	      if (PREDICT_TRUE (vnet_buffer (p0)->ip.flow_hash))
+		{
+		  hc0 = vnet_buffer (p0)->ip.flow_hash =
+		    vnet_buffer (p0)->ip.flow_hash >> 1;
+		}
+	      else
+		{
+		  hc0 = vnet_buffer (p0)->ip.flow_hash =
+		    ip4_compute_flow_hash (ip0, hc0);
+		}
+	    }
+	  if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
+	    {
+	      if (PREDICT_TRUE (vnet_buffer (p1)->ip.flow_hash))
+		{
+		  hc1 = vnet_buffer (p1)->ip.flow_hash =
+		    vnet_buffer (p1)->ip.flow_hash >> 1;
+		}
+	      else
+		{
+		  hc1 = vnet_buffer (p1)->ip.flow_hash =
+		    ip4_compute_flow_hash (ip1, hc1);
+		}
+	    }
+
+	  dpo0 =
+	    load_balance_get_bucket_i (lb0,
+				       hc0 & (lb0->lb_n_buckets_minus_1));
+	  dpo1 =
+	    load_balance_get_bucket_i (lb1,
+				       hc1 & (lb1->lb_n_buckets_minus_1));
+
+	  next0 = dpo0->dpoi_next_node;
+	  next1 = dpo1->dpoi_next_node;
+
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+	  vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
+
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lbi0, 1, vlib_buffer_length_in_chain (vm, p0));
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lbi1, 1, vlib_buffer_length_in_chain (vm, p1));
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next,
+					   to_next, n_left_to_next,
+					   pi0, pi1, next0, next1);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  ip_lookup_next_t next0;
+	  const load_balance_t *lb0;
+	  vlib_buffer_t *p0;
+	  u32 pi0, lbi0, hc0;
+	  const ip4_header_t *ip0;
+	  const dpo_id_t *dpo0;
+
+	  pi0 = from[0];
+	  to_next[0] = pi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+	  n_left_from -= 1;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  lbi0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+
+	  lb0 = load_balance_get (lbi0);
+
+	  hc0 = vnet_buffer (p0)->ip.flow_hash = 0;
+	  if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
+	    {
+	      if (PREDICT_TRUE (vnet_buffer (p0)->ip.flow_hash))
+		{
+		  hc0 = vnet_buffer (p0)->ip.flow_hash =
+		    vnet_buffer (p0)->ip.flow_hash >> 1;
+		}
+	      else
+		{
+		  hc0 = vnet_buffer (p0)->ip.flow_hash =
+		    ip4_compute_flow_hash (ip0, hc0);
+		}
+	    }
+
+	  dpo0 =
+	    load_balance_get_bucket_i (lb0,
+				       hc0 & (lb0->lb_n_buckets_minus_1));
+
+	  next0 = dpo0->dpoi_next_node;
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+
+	  vlib_increment_combined_counter
+	    (cm, cpu_index, lbi0, 1, vlib_buffer_length_in_chain (vm, p0));
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next,
+					   to_next, n_left_to_next,
+					   pi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next, n_left_to_next);
+    }
+
+  return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (ip4_load_balance_node) =
+{
+.function = ip4_load_balance,.name = "ip4-load-balance",.vector_size =
+    sizeof (u32),.sibling_of = "ip4-lookup",.format_trace =
+    format_ip4_lookup_trace,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_load_balance_node, ip4_load_balance);
+
+/* get first interface address */
+ip4_address_t *
+ip4_interface_first_address (ip4_main_t * im, u32 sw_if_index,
+			     ip_interface_address_t ** result_ia)
+{
+  ip_lookup_main_t *lm = &im->lookup_main;
+  ip_interface_address_t *ia = 0;
+  ip4_address_t *result = 0;
+
+  foreach_ip_interface_address (lm, ia, sw_if_index,
+				1 /* honor unnumbered */ ,
+				(
+				  {
+				  ip4_address_t * a =
+				  ip_interface_address_get_address (lm, ia);
+				  result = a;
+				  break;
+				  }
+				));
+  if (result_ia)
+    *result_ia = result ? ia : 0;
+  return result;
+}
+
+static void
+ip4_add_interface_routes (u32 sw_if_index,
+			  ip4_main_t * im, u32 fib_index,
+			  ip_interface_address_t * a)
+{
+  ip_lookup_main_t *lm = &im->lookup_main;
+  ip4_address_t *address = ip_interface_address_get_address (lm, a);
+  fib_prefix_t pfx = {
+    .fp_len = a->address_length,
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_addr.ip4 = *address,
+  };
+
+  a->neighbor_probe_adj_index = ~0;
+
+  if (pfx.fp_len < 32)
+    {
+      fib_node_index_t fei;
+
+      fei = fib_table_entry_update_one_path (fib_index, &pfx, FIB_SOURCE_INTERFACE, (FIB_ENTRY_FLAG_CONNECTED | FIB_ENTRY_FLAG_ATTACHED), FIB_PROTOCOL_IP4, NULL,	/* No next-hop address */
+					     sw_if_index, ~0,	// invalid FIB index
+					     1, NULL,	// no out-label stack
+					     FIB_ROUTE_PATH_FLAG_NONE);
+      a->neighbor_probe_adj_index = fib_entry_get_adj (fei);
+    }
+
+  pfx.fp_len = 32;
+
+  if (sw_if_index < vec_len (lm->classify_table_index_by_sw_if_index))
+    {
+      u32 classify_table_index =
+	lm->classify_table_index_by_sw_if_index[sw_if_index];
+      if (classify_table_index != (u32) ~ 0)
+	{
+	  dpo_id_t dpo = DPO_INVALID;
+
+	  dpo_set (&dpo,
+		   DPO_CLASSIFY,
+		   DPO_PROTO_IP4,
+		   classify_dpo_create (DPO_PROTO_IP4, classify_table_index));
+
+	  fib_table_entry_special_dpo_add (fib_index,
+					   &pfx,
+					   FIB_SOURCE_CLASSIFY,
+					   FIB_ENTRY_FLAG_NONE, &dpo);
+	  dpo_reset (&dpo);
+	}
+    }
+
+  fib_table_entry_update_one_path (fib_index, &pfx, FIB_SOURCE_INTERFACE, (FIB_ENTRY_FLAG_CONNECTED | FIB_ENTRY_FLAG_LOCAL), FIB_PROTOCOL_IP4, &pfx.fp_addr, sw_if_index, ~0,	// invalid FIB index
+				   1, NULL,	// no out-label stack
+				   FIB_ROUTE_PATH_FLAG_NONE);
+}
+
+static void
+ip4_del_interface_routes (ip4_main_t * im,
+			  u32 fib_index,
+			  ip4_address_t * address, u32 address_length)
+{
+  fib_prefix_t pfx = {
+    .fp_len = address_length,
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_addr.ip4 = *address,
+  };
+
+  if (pfx.fp_len < 32)
+    {
+      fib_table_entry_delete (fib_index, &pfx, FIB_SOURCE_INTERFACE);
+    }
+
+  pfx.fp_len = 32;
+  fib_table_entry_delete (fib_index, &pfx, FIB_SOURCE_INTERFACE);
+}
+
+void
+ip4_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
+{
+  ip4_main_t *im = &ip4_main;
+
+  vec_validate_init_empty (im->ip_enabled_by_sw_if_index, sw_if_index, 0);
+
+  /*
+   * enable/disable only on the 1<->0 transition
+   */
+  if (is_enable)
+    {
+      if (1 != ++im->ip_enabled_by_sw_if_index[sw_if_index])
+	return;
+    }
+  else
+    {
+      ASSERT (im->ip_enabled_by_sw_if_index[sw_if_index] > 0);
+      if (0 != --im->ip_enabled_by_sw_if_index[sw_if_index])
+	return;
+    }
+  vnet_feature_enable_disable ("ip4-unicast", "ip4-drop", sw_if_index,
+			       !is_enable, 0, 0);
+
+  vnet_feature_enable_disable ("ip4-multicast", "ip4-drop", sw_if_index,
+			       !is_enable, 0, 0);
+
+}
+
+static clib_error_t *
+ip4_add_del_interface_address_internal (vlib_main_t * vm,
+					u32 sw_if_index,
+					ip4_address_t * address,
+					u32 address_length, u32 is_del)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  clib_error_t *error = 0;
+  u32 if_address_index, elts_before;
+  ip4_address_fib_t ip4_af, *addr_fib = 0;
+
+  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
+  ip4_addr_fib_init (&ip4_af, address,
+		     vec_elt (im->fib_index_by_sw_if_index, sw_if_index));
+  vec_add1 (addr_fib, ip4_af);
+
+  /* FIXME-LATER
+   * there is no support for adj-fib handling in the presence of overlapping
+   * subnets on interfaces. Easy fix - disallow overlapping subnets, like
+   * most routers do.
+   */
+  if (!is_del)
+    {
+      /* When adding an address check that it does not conflict
+         with an existing address. */
+      ip_interface_address_t *ia;
+      foreach_ip_interface_address (&im->lookup_main, ia, sw_if_index,
+				    0 /* honor unnumbered */ ,
+				    (
+				      {
+				      ip4_address_t * x =
+				      ip_interface_address_get_address
+				      (&im->lookup_main, ia);
+				      if (ip4_destination_matches_route
+					  (im, address, x, ia->address_length)
+					  ||
+					  ip4_destination_matches_route (im,
+									 x,
+									 address,
+									 address_length))
+				      return
+				      clib_error_create
+				      ("failed to add %U which conflicts with %U for interface %U",
+				       format_ip4_address_and_length, address,
+				       address_length,
+				       format_ip4_address_and_length, x,
+				       ia->address_length,
+				       format_vnet_sw_if_index_name, vnm,
+				       sw_if_index);}
+				    ));
+    }
+
+  elts_before = pool_elts (lm->if_address_pool);
+
+  error = ip_interface_address_add_del
+    (lm, sw_if_index, addr_fib, address_length, is_del, &if_address_index);
+  if (error)
+    goto done;
+
+  ip4_sw_interface_enable_disable (sw_if_index, !is_del);
+
+  if (is_del)
+    ip4_del_interface_routes (im, ip4_af.fib_index, address, address_length);
+  else
+    ip4_add_interface_routes (sw_if_index,
+			      im, ip4_af.fib_index,
+			      pool_elt_at_index
+			      (lm->if_address_pool, if_address_index));
+
+  /* If pool did not grow/shrink: add duplicate address. */
+  if (elts_before != pool_elts (lm->if_address_pool))
+    {
+      ip4_add_del_interface_address_callback_t *cb;
+      vec_foreach (cb, im->add_del_interface_address_callbacks)
+	cb->function (im, cb->function_opaque, sw_if_index,
+		      address, address_length, if_address_index, is_del);
+    }
+
+done:
+  vec_free (addr_fib);
+  return error;
+}
+
+clib_error_t *
+ip4_add_del_interface_address (vlib_main_t * vm, u32 sw_if_index,
+			       ip4_address_t * address, u32 address_length,
+			       u32 is_del)
+{
+  return ip4_add_del_interface_address_internal
+    (vm, sw_if_index, address, address_length, is_del);
+}
+
+/* Built-in ip4 unicast rx feature path definition */
+/* *INDENT-OFF* */
+VNET_FEATURE_ARC_INIT (ip4_unicast, static) =
+{
+  .arc_name = "ip4-unicast",
+  .start_nodes = VNET_FEATURES ("ip4-input", "ip4-input-no-checksum"),
+  .end_node = "ip4-lookup",
+  .arc_index_ptr = &ip4_main.lookup_main.ucast_feature_arc_index,
+};
+
+VNET_FEATURE_INIT (ip4_flow_classify, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-flow-classify",
+  .runs_before = VNET_FEATURES ("ip4-inacl"),
+};
+
+VNET_FEATURE_INIT (ip4_inacl, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-inacl",
+  .runs_before = VNET_FEATURES ("ip4-source-check-via-rx"),
+};
+
+VNET_FEATURE_INIT (ip4_source_check_1, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-source-check-via-rx",
+  .runs_before = VNET_FEATURES ("ip4-source-check-via-any"),
+};
+
+VNET_FEATURE_INIT (ip4_source_check_2, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-source-check-via-any",
+  .runs_before = VNET_FEATURES ("ip4-policer-classify"),
+};
+
+VNET_FEATURE_INIT (ip4_source_and_port_range_check_rx, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-source-and-port-range-check-rx",
+  .runs_before = VNET_FEATURES ("ip4-policer-classify"),
+};
+
+VNET_FEATURE_INIT (ip4_policer_classify, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-policer-classify",
+  .runs_before = VNET_FEATURES ("ipsec-input-ip4"),
+};
+
+VNET_FEATURE_INIT (ip4_ipsec, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ipsec-input-ip4",
+  .runs_before = VNET_FEATURES ("vpath-input-ip4"),
+};
+
+VNET_FEATURE_INIT (ip4_vpath, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "vpath-input-ip4",
+  .runs_before = VNET_FEATURES ("ip4-vxlan-bypass"),
+};
+
+VNET_FEATURE_INIT (ip4_vxlan_bypass, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-vxlan-bypass",
+  .runs_before = VNET_FEATURES ("ip4-lookup"),
+};
+
+VNET_FEATURE_INIT (ip4_lookup, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-lookup",
+  .runs_before = VNET_FEATURES ("ip4-drop"),
+};
+
+VNET_FEATURE_INIT (ip4_drop, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-drop",
+  .runs_before = 0,	/* not before any other features */
+};
+
+
+/* Built-in ip4 multicast rx feature path definition */
+VNET_FEATURE_ARC_INIT (ip4_multicast, static) =
+{
+  .arc_name = "ip4-multicast",
+  .start_nodes = VNET_FEATURES ("ip4-input", "ip4-input-no-checksum"),
+  .end_node = "ip4-lookup-multicast",
+  .arc_index_ptr = &ip4_main.lookup_main.mcast_feature_arc_index,
+};
+
+VNET_FEATURE_INIT (ip4_vpath_mc, static) =
+{
+  .arc_name = "ip4-multicast",
+  .node_name = "vpath-input-ip4",
+  .runs_before = VNET_FEATURES ("ip4-lookup-multicast"),
+};
+
+VNET_FEATURE_INIT (ip4_lookup_mc, static) =
+{
+  .arc_name = "ip4-multicast",
+  .node_name = "ip4-lookup-multicast",
+  .runs_before = VNET_FEATURES ("ip4-drop"),
+};
+
+VNET_FEATURE_INIT (ip4_mc_drop, static) =
+{
+  .arc_name = "ip4-multicast",
+  .node_name = "ip4-drop",
+  .runs_before = 0,	/* last feature */
+};
+
+/* Source and port-range check ip4 tx feature path definition */
+VNET_FEATURE_ARC_INIT (ip4_output, static) =
+{
+  .arc_name = "ip4-output",
+  .start_nodes = VNET_FEATURES ("ip4-rewrite", "ip4-midchain"),
+  .end_node = "interface-output",
+  .arc_index_ptr = &ip4_main.lookup_main.output_feature_arc_index,
+};
+
+VNET_FEATURE_INIT (ip4_source_and_port_range_check_tx, static) =
+{
+  .arc_name = "ip4-output",
+  .node_name = "ip4-source-and-port-range-check-tx",
+  .runs_before = VNET_FEATURES ("ipsec-output-ip4"),
+};
+
+VNET_FEATURE_INIT (ip4_ipsec_output, static) =
+{
+  .arc_name = "ip4-output",
+  .node_name = "ipsec-output-ip4",
+  .runs_before = VNET_FEATURES ("interface-output"),
+};
+
+/* Built-in ip4 tx feature path definition */
+VNET_FEATURE_INIT (ip4_interface_output, static) =
+{
+  .arc_name = "ip4-output",
+  .node_name = "interface-output",
+  .runs_before = 0,	/* not before any other features */
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+ip4_sw_interface_add_del (vnet_main_t * vnm, u32 sw_if_index, u32 is_add)
+{
+  ip4_main_t *im = &ip4_main;
+
+  /* Fill in lookup tables with default table (0). */
+  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
+
+  vnet_feature_enable_disable ("ip4-unicast", "ip4-drop", sw_if_index,
+			       is_add, 0, 0);
+
+  vnet_feature_enable_disable ("ip4-multicast", "ip4-drop", sw_if_index,
+			       is_add, 0, 0);
+
+  return /* no error */ 0;
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION (ip4_sw_interface_add_del);
+
+/* Global IP4 main. */
+ip4_main_t ip4_main;
+
+clib_error_t *
+ip4_lookup_init (vlib_main_t * vm)
+{
+  ip4_main_t *im = &ip4_main;
+  clib_error_t *error;
+  uword i;
+
+  if ((error = vlib_call_init_function (vm, vnet_feature_init)))
+    return error;
+
+  for (i = 0; i < ARRAY_LEN (im->fib_masks); i++)
+    {
+      u32 m;
+
+      if (i < 32)
+	m = pow2_mask (i) << (32 - i);
+      else
+	m = ~0;
+      im->fib_masks[i] = clib_host_to_net_u32 (m);
+    }
+
+  ip_lookup_init (&im->lookup_main, /* is_ip6 */ 0);
+
+  /* Create FIB with index 0 and table id of 0. */
+  fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4, 0);
+
+  {
+    pg_node_t *pn;
+    pn = pg_get_node (ip4_lookup_node.index);
+    pn->unformat_edit = unformat_pg_ip4_header;
+  }
+
+  {
+    ethernet_arp_header_t h;
+
+    memset (&h, 0, sizeof (h));
+
+    /* Set target ethernet address to all zeros. */
+    memset (h.ip4_over_ethernet[1].ethernet, 0,
+	    sizeof (h.ip4_over_ethernet[1].ethernet));
+
+#define _16(f,v) h.f = clib_host_to_net_u16 (v);
+#define _8(f,v) h.f = v;
+    _16 (l2_type, ETHERNET_ARP_HARDWARE_TYPE_ethernet);
+    _16 (l3_type, ETHERNET_TYPE_IP4);
+    _8 (n_l2_address_bytes, 6);
+    _8 (n_l3_address_bytes, 4);
+    _16 (opcode, ETHERNET_ARP_OPCODE_request);
+#undef _16
+#undef _8
+
+    vlib_packet_template_init (vm, &im->ip4_arp_request_packet_template,
+			       /* data */ &h,
+			       sizeof (h),
+			       /* alloc chunk size */ 8,
+			       "ip4 arp");
+  }
+
+  return error;
+}
+
+VLIB_INIT_FUNCTION (ip4_lookup_init);
+
+typedef struct
+{
+  /* Adjacency taken. */
+  u32 dpo_index;
+  u32 flow_hash;
+  u32 fib_index;
+
+  /* Packet data, possibly *after* rewrite. */
+  u8 packet_data[64 - 1 * sizeof (u32)];
+}
+ip4_forward_next_trace_t;
+
+u8 *
+format_ip4_forward_next_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 *);
+  ip4_forward_next_trace_t *t = va_arg (*args, ip4_forward_next_trace_t *);
+  uword indent = format_get_indent (s);
+  s = format (s, "%U%U",
+	      format_white_space, indent,
+	      format_ip4_header, t->packet_data, sizeof (t->packet_data));
+  return s;
+}
+
+static u8 *
+format_ip4_lookup_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 *);
+  ip4_forward_next_trace_t *t = va_arg (*args, ip4_forward_next_trace_t *);
+  uword indent = format_get_indent (s);
+
+  s = format (s, "fib %d dpo-idx %d flow hash: 0x%08x",
+	      t->fib_index, t->dpo_index, t->flow_hash);
+  s = format (s, "\n%U%U",
+	      format_white_space, indent,
+	      format_ip4_header, t->packet_data, sizeof (t->packet_data));
+  return s;
+}
+
+static u8 *
+format_ip4_rewrite_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 *);
+  ip4_forward_next_trace_t *t = va_arg (*args, ip4_forward_next_trace_t *);
+  vnet_main_t *vnm = vnet_get_main ();
+  uword indent = format_get_indent (s);
+
+  s = format (s, "tx_sw_if_index %d dpo-idx %d : %U flow hash: 0x%08x",
+	      t->fib_index, t->dpo_index, format_ip_adjacency,
+	      t->dpo_index, FORMAT_IP_ADJACENCY_NONE, t->flow_hash);
+  s = format (s, "\n%U%U",
+	      format_white_space, indent,
+	      format_ip_adjacency_packet_data,
+	      vnm, t->dpo_index, t->packet_data, sizeof (t->packet_data));
+  return s;
+}
+
+/* Common trace function for all ip4-forward next nodes. */
+void
+ip4_forward_next_trace (vlib_main_t * vm,
+			vlib_node_runtime_t * node,
+			vlib_frame_t * frame, vlib_rx_or_tx_t which_adj_index)
+{
+  u32 *from, n_left;
+  ip4_main_t *im = &ip4_main;
+
+  n_left = frame->n_vectors;
+  from = vlib_frame_vector_args (frame);
+
+  while (n_left >= 4)
+    {
+      u32 bi0, bi1;
+      vlib_buffer_t *b0, *b1;
+      ip4_forward_next_trace_t *t0, *t1;
+
+      /* Prefetch next iteration. */
+      vlib_prefetch_buffer_with_index (vm, from[2], LOAD);
+      vlib_prefetch_buffer_with_index (vm, from[3], LOAD);
+
+      bi0 = from[0];
+      bi1 = from[1];
+
+      b0 = vlib_get_buffer (vm, bi0);
+      b1 = vlib_get_buffer (vm, bi1);
+
+      if (b0->flags & VLIB_BUFFER_IS_TRACED)
+	{
+	  t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
+	  t0->dpo_index = vnet_buffer (b0)->ip.adj_index[which_adj_index];
+	  t0->flow_hash = vnet_buffer (b0)->ip.flow_hash;
+	  t0->fib_index =
+	    (vnet_buffer (b0)->sw_if_index[VLIB_TX] !=
+	     (u32) ~ 0) ? vnet_buffer (b0)->sw_if_index[VLIB_TX] :
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (b0)->sw_if_index[VLIB_RX]);
+
+	  clib_memcpy (t0->packet_data,
+		       vlib_buffer_get_current (b0),
+		       sizeof (t0->packet_data));
+	}
+      if (b1->flags & VLIB_BUFFER_IS_TRACED)
+	{
+	  t1 = vlib_add_trace (vm, node, b1, sizeof (t1[0]));
+	  t1->dpo_index = vnet_buffer (b1)->ip.adj_index[which_adj_index];
+	  t1->flow_hash = vnet_buffer (b1)->ip.flow_hash;
+	  t1->fib_index =
+	    (vnet_buffer (b1)->sw_if_index[VLIB_TX] !=
+	     (u32) ~ 0) ? vnet_buffer (b1)->sw_if_index[VLIB_TX] :
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (b1)->sw_if_index[VLIB_RX]);
+	  clib_memcpy (t1->packet_data, vlib_buffer_get_current (b1),
+		       sizeof (t1->packet_data));
+	}
+      from += 2;
+      n_left -= 2;
+    }
+
+  while (n_left >= 1)
+    {
+      u32 bi0;
+      vlib_buffer_t *b0;
+      ip4_forward_next_trace_t *t0;
+
+      bi0 = from[0];
+
+      b0 = vlib_get_buffer (vm, bi0);
+
+      if (b0->flags & VLIB_BUFFER_IS_TRACED)
+	{
+	  t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
+	  t0->dpo_index = vnet_buffer (b0)->ip.adj_index[which_adj_index];
+	  t0->flow_hash = vnet_buffer (b0)->ip.flow_hash;
+	  t0->fib_index =
+	    (vnet_buffer (b0)->sw_if_index[VLIB_TX] !=
+	     (u32) ~ 0) ? vnet_buffer (b0)->sw_if_index[VLIB_TX] :
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (b0)->sw_if_index[VLIB_RX]);
+	  clib_memcpy (t0->packet_data, vlib_buffer_get_current (b0),
+		       sizeof (t0->packet_data));
+	}
+      from += 1;
+      n_left -= 1;
+    }
+}
+
+static uword
+ip4_drop_or_punt (vlib_main_t * vm,
+		  vlib_node_runtime_t * node,
+		  vlib_frame_t * frame, ip4_error_t error_code)
+{
+  u32 *buffers = vlib_frame_vector_args (frame);
+  uword n_packets = frame->n_vectors;
+
+  vlib_error_drop_buffers (vm, node, buffers,
+			   /* stride */ 1,
+			   n_packets,
+			   /* next */ 0,
+			   ip4_input_node.index, error_code);
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  return n_packets;
+}
+
+static uword
+ip4_drop (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return ip4_drop_or_punt (vm, node, frame, IP4_ERROR_ADJACENCY_DROP);
+}
+
+static uword
+ip4_punt (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return ip4_drop_or_punt (vm, node, frame, IP4_ERROR_ADJACENCY_PUNT);
+}
+
+VLIB_REGISTER_NODE (ip4_drop_node, static) =
+{
+  .function = ip4_drop,.name = "ip4-drop",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_next_nodes =
+    1,.next_nodes =
+  {
+  [0] = "error-drop",}
+,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_drop_node, ip4_drop);
+
+VLIB_REGISTER_NODE (ip4_punt_node, static) =
+{
+  .function = ip4_punt,.name = "ip4-punt",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_next_nodes =
+    1,.next_nodes =
+  {
+  [0] = "error-punt",}
+,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_punt_node, ip4_punt);
+
+/* Compute TCP/UDP/ICMP4 checksum in software. */
+u16
+ip4_tcp_udp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+			      ip4_header_t * ip0)
+{
+  ip_csum_t sum0;
+  u32 ip_header_length, payload_length_host_byte_order;
+  u32 n_this_buffer, n_bytes_left;
+  u16 sum16;
+  void *data_this_buffer;
+
+  /* Initialize checksum with ip header. */
+  ip_header_length = ip4_header_bytes (ip0);
+  payload_length_host_byte_order =
+    clib_net_to_host_u16 (ip0->length) - ip_header_length;
+  sum0 =
+    clib_host_to_net_u32 (payload_length_host_byte_order +
+			  (ip0->protocol << 16));
+
+  if (BITS (uword) == 32)
+    {
+      sum0 =
+	ip_csum_with_carry (sum0,
+			    clib_mem_unaligned (&ip0->src_address, u32));
+      sum0 =
+	ip_csum_with_carry (sum0,
+			    clib_mem_unaligned (&ip0->dst_address, u32));
+    }
+  else
+    sum0 =
+      ip_csum_with_carry (sum0, clib_mem_unaligned (&ip0->src_address, u64));
+
+  n_bytes_left = n_this_buffer = payload_length_host_byte_order;
+  data_this_buffer = (void *) ip0 + ip_header_length;
+  if (n_this_buffer + ip_header_length > p0->current_length)
+    n_this_buffer =
+      p0->current_length >
+      ip_header_length ? p0->current_length - ip_header_length : 0;
+  while (1)
+    {
+      sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
+      n_bytes_left -= n_this_buffer;
+      if (n_bytes_left == 0)
+	break;
+
+      ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT);
+      p0 = vlib_get_buffer (vm, p0->next_buffer);
+      data_this_buffer = vlib_buffer_get_current (p0);
+      n_this_buffer = p0->current_length;
+    }
+
+  sum16 = ~ip_csum_fold (sum0);
+
+  return sum16;
+}
+
+u32
+ip4_tcp_udp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0)
+{
+  ip4_header_t *ip0 = vlib_buffer_get_current (p0);
+  udp_header_t *udp0;
+  u16 sum16;
+
+  ASSERT (ip0->protocol == IP_PROTOCOL_TCP
+	  || ip0->protocol == IP_PROTOCOL_UDP);
+
+  udp0 = (void *) (ip0 + 1);
+  if (ip0->protocol == IP_PROTOCOL_UDP && udp0->checksum == 0)
+    {
+      p0->flags |= (IP_BUFFER_L4_CHECKSUM_COMPUTED
+		    | IP_BUFFER_L4_CHECKSUM_CORRECT);
+      return p0->flags;
+    }
+
+  sum16 = ip4_tcp_udp_compute_checksum (vm, p0, ip0);
+
+  p0->flags |= (IP_BUFFER_L4_CHECKSUM_COMPUTED
+		| ((sum16 == 0) << LOG2_IP_BUFFER_L4_CHECKSUM_CORRECT));
+
+  return p0->flags;
+}
+
+static uword
+ip4_local (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  ip_local_next_t next_index;
+  u32 *from, *to_next, n_left_from, n_left_to_next;
+  vlib_node_runtime_t *error_node =
+    vlib_node_get_runtime (vm, ip4_input_node.index);
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  vlib_buffer_t *p0, *p1;
+	  ip4_header_t *ip0, *ip1;
+	  udp_header_t *udp0, *udp1;
+	  ip4_fib_mtrie_t *mtrie0, *mtrie1;
+	  ip4_fib_mtrie_leaf_t leaf0, leaf1;
+	  const dpo_id_t *dpo0, *dpo1;
+	  const load_balance_t *lb0, *lb1;
+	  u32 pi0, ip_len0, udp_len0, flags0, next0, fib_index0, lbi0;
+	  u32 pi1, ip_len1, udp_len1, flags1, next1, fib_index1, lbi1;
+	  i32 len_diff0, len_diff1;
+	  u8 error0, is_udp0, is_tcp_udp0, good_tcp_udp0, proto0;
+	  u8 error1, is_udp1, is_tcp_udp1, good_tcp_udp1, proto1;
+	  u8 enqueue_code;
+
+	  pi0 = to_next[0] = from[0];
+	  pi1 = to_next[1] = from[1];
+	  from += 2;
+	  n_left_from -= 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  p1 = vlib_get_buffer (vm, pi1);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  ip1 = vlib_buffer_get_current (p1);
+
+	  vnet_buffer (p0)->ip.start_of_ip_header = p0->current_data;
+	  vnet_buffer (p1)->ip.start_of_ip_header = p1->current_data;
+
+	  fib_index0 = vec_elt (im->fib_index_by_sw_if_index,
+				vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index0 = (vnet_buffer (p0)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	    fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+
+	  fib_index1 = vec_elt (im->fib_index_by_sw_if_index,
+				vnet_buffer (p1)->sw_if_index[VLIB_RX]);
+	  fib_index1 = (vnet_buffer (p1)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	    fib_index1 : vnet_buffer (p1)->sw_if_index[VLIB_TX];
+
+	  mtrie0 = &ip4_fib_get (fib_index0)->mtrie;
+	  mtrie1 = &ip4_fib_get (fib_index1)->mtrie;
+
+	  leaf0 = leaf1 = IP4_FIB_MTRIE_LEAF_ROOT;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 0);
+	  leaf1 =
+	    ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 0);
+
+	  /* Treat IP frag packets as "experimental" protocol for now
+	     until support of IP frag reassembly is implemented */
+	  proto0 = ip4_is_fragment (ip0) ? 0xfe : ip0->protocol;
+	  proto1 = ip4_is_fragment (ip1) ? 0xfe : ip1->protocol;
+	  is_udp0 = proto0 == IP_PROTOCOL_UDP;
+	  is_udp1 = proto1 == IP_PROTOCOL_UDP;
+	  is_tcp_udp0 = is_udp0 || proto0 == IP_PROTOCOL_TCP;
+	  is_tcp_udp1 = is_udp1 || proto1 == IP_PROTOCOL_TCP;
+
+	  flags0 = p0->flags;
+	  flags1 = p1->flags;
+
+	  good_tcp_udp0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+	  good_tcp_udp1 = (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+
+	  udp0 = ip4_next_header (ip0);
+	  udp1 = ip4_next_header (ip1);
+
+	  /* Don't verify UDP checksum for packets with explicit zero checksum. */
+	  good_tcp_udp0 |= is_udp0 && udp0->checksum == 0;
+	  good_tcp_udp1 |= is_udp1 && udp1->checksum == 0;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 1);
+	  leaf1 =
+	    ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 1);
+
+	  /* Verify UDP length. */
+	  ip_len0 = clib_net_to_host_u16 (ip0->length);
+	  ip_len1 = clib_net_to_host_u16 (ip1->length);
+	  udp_len0 = clib_net_to_host_u16 (udp0->length);
+	  udp_len1 = clib_net_to_host_u16 (udp1->length);
+
+	  len_diff0 = ip_len0 - udp_len0;
+	  len_diff1 = ip_len1 - udp_len1;
+
+	  len_diff0 = is_udp0 ? len_diff0 : 0;
+	  len_diff1 = is_udp1 ? len_diff1 : 0;
+
+	  if (PREDICT_FALSE (!(is_tcp_udp0 & is_tcp_udp1
+			       & good_tcp_udp0 & good_tcp_udp1)))
+	    {
+	      if (is_tcp_udp0)
+		{
+		  if (is_tcp_udp0
+		      && !(flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED))
+		    flags0 = ip4_tcp_udp_validate_checksum (vm, p0);
+		  good_tcp_udp0 =
+		    (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+		  good_tcp_udp0 |= is_udp0 && udp0->checksum == 0;
+		}
+	      if (is_tcp_udp1)
+		{
+		  if (is_tcp_udp1
+		      && !(flags1 & IP_BUFFER_L4_CHECKSUM_COMPUTED))
+		    flags1 = ip4_tcp_udp_validate_checksum (vm, p1);
+		  good_tcp_udp1 =
+		    (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+		  good_tcp_udp1 |= is_udp1 && udp1->checksum == 0;
+		}
+	    }
+
+	  good_tcp_udp0 &= len_diff0 >= 0;
+	  good_tcp_udp1 &= len_diff1 >= 0;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 2);
+	  leaf1 =
+	    ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 2);
+
+	  error0 = error1 = IP4_ERROR_UNKNOWN_PROTOCOL;
+
+	  error0 = len_diff0 < 0 ? IP4_ERROR_UDP_LENGTH : error0;
+	  error1 = len_diff1 < 0 ? IP4_ERROR_UDP_LENGTH : error1;
+
+	  ASSERT (IP4_ERROR_TCP_CHECKSUM + 1 == IP4_ERROR_UDP_CHECKSUM);
+	  error0 = (is_tcp_udp0 && !good_tcp_udp0
+		    ? IP4_ERROR_TCP_CHECKSUM + is_udp0 : error0);
+	  error1 = (is_tcp_udp1 && !good_tcp_udp1
+		    ? IP4_ERROR_TCP_CHECKSUM + is_udp1 : error1);
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 3);
+	  leaf1 =
+	    ip4_fib_mtrie_lookup_step (mtrie1, leaf1, &ip1->src_address, 3);
+	  leaf0 =
+	    (leaf0 ==
+	     IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie0->default_leaf : leaf0);
+	  leaf1 =
+	    (leaf1 ==
+	     IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie1->default_leaf : leaf1);
+
+	  vnet_buffer (p0)->ip.adj_index[VLIB_RX] = lbi0 =
+	    ip4_fib_mtrie_leaf_get_adj_index (leaf0);
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = lbi0;
+
+	  vnet_buffer (p1)->ip.adj_index[VLIB_RX] = lbi1 =
+	    ip4_fib_mtrie_leaf_get_adj_index (leaf1);
+	  vnet_buffer (p1)->ip.adj_index[VLIB_TX] = lbi1;
+
+	  lb0 = load_balance_get (lbi0);
+	  lb1 = load_balance_get (lbi1);
+	  dpo0 = load_balance_get_bucket_i (lb0, 0);
+	  dpo1 = load_balance_get_bucket_i (lb1, 0);
+
+	  /*
+	   * Must have a route to source otherwise we drop the packet.
+	   * ip4 broadcasts are accepted, e.g. to make dhcp client work
+	   *
+	   * The checks are:
+	   *  - the source is a recieve => it's from us => bogus, do this
+	   *    first since it sets a different error code.
+	   *  - uRPF check for any route to source - accept if passes.
+	   *  - allow packets destined to the broadcast address from unknown sources
+	   */
+	  error0 = ((error0 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     dpo0->dpoi_type == DPO_RECEIVE) ?
+		    IP4_ERROR_SPOOFED_LOCAL_PACKETS : error0);
+	  error0 = ((error0 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     !fib_urpf_check_size (lb0->lb_urpf) &&
+		     ip0->dst_address.as_u32 != 0xFFFFFFFF)
+		    ? IP4_ERROR_SRC_LOOKUP_MISS : error0);
+	  error1 = ((error1 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     dpo1->dpoi_type == DPO_RECEIVE) ?
+		    IP4_ERROR_SPOOFED_LOCAL_PACKETS : error1);
+	  error1 = ((error1 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     !fib_urpf_check_size (lb1->lb_urpf) &&
+		     ip1->dst_address.as_u32 != 0xFFFFFFFF)
+		    ? IP4_ERROR_SRC_LOOKUP_MISS : error1);
+
+	  next0 = lm->local_next_by_ip_protocol[proto0];
+	  next1 = lm->local_next_by_ip_protocol[proto1];
+
+	  next0 =
+	    error0 != IP4_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next0;
+	  next1 =
+	    error1 != IP4_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next1;
+
+	  p0->error = error0 ? error_node->errors[error0] : 0;
+	  p1->error = error1 ? error_node->errors[error1] : 0;
+
+	  enqueue_code = (next0 != next_index) + 2 * (next1 != next_index);
+
+	  if (PREDICT_FALSE (enqueue_code != 0))
+	    {
+	      switch (enqueue_code)
+		{
+		case 1:
+		  /* A B A */
+		  to_next[-2] = pi1;
+		  to_next -= 1;
+		  n_left_to_next += 1;
+		  vlib_set_next_frame_buffer (vm, node, next0, pi0);
+		  break;
+
+		case 2:
+		  /* A A B */
+		  to_next -= 1;
+		  n_left_to_next += 1;
+		  vlib_set_next_frame_buffer (vm, node, next1, pi1);
+		  break;
+
+		case 3:
+		  /* A B B or A B C */
+		  to_next -= 2;
+		  n_left_to_next += 2;
+		  vlib_set_next_frame_buffer (vm, node, next0, pi0);
+		  vlib_set_next_frame_buffer (vm, node, next1, pi1);
+		  if (next0 == next1)
+		    {
+		      vlib_put_next_frame (vm, node, next_index,
+					   n_left_to_next);
+		      next_index = next1;
+		      vlib_get_next_frame (vm, node, next_index, to_next,
+					   n_left_to_next);
+		    }
+		  break;
+		}
+	    }
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *p0;
+	  ip4_header_t *ip0;
+	  udp_header_t *udp0;
+	  ip4_fib_mtrie_t *mtrie0;
+	  ip4_fib_mtrie_leaf_t leaf0;
+	  u32 pi0, next0, ip_len0, udp_len0, flags0, fib_index0, lbi0;
+	  i32 len_diff0;
+	  u8 error0, is_udp0, is_tcp_udp0, good_tcp_udp0, proto0;
+	  load_balance_t *lb0;
+	  const dpo_id_t *dpo0;
+
+	  pi0 = to_next[0] = from[0];
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  vnet_buffer (p0)->ip.start_of_ip_header = p0->current_data;
+
+	  fib_index0 = vec_elt (im->fib_index_by_sw_if_index,
+				vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index0 = (vnet_buffer (p0)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	    fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+
+	  mtrie0 = &ip4_fib_get (fib_index0)->mtrie;
+
+	  leaf0 = IP4_FIB_MTRIE_LEAF_ROOT;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 0);
+
+	  /* Treat IP frag packets as "experimental" protocol for now
+	     until support of IP frag reassembly is implemented */
+	  proto0 = ip4_is_fragment (ip0) ? 0xfe : ip0->protocol;
+	  is_udp0 = proto0 == IP_PROTOCOL_UDP;
+	  is_tcp_udp0 = is_udp0 || proto0 == IP_PROTOCOL_TCP;
+
+	  flags0 = p0->flags;
+
+	  good_tcp_udp0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+
+	  udp0 = ip4_next_header (ip0);
+
+	  /* Don't verify UDP checksum for packets with explicit zero checksum. */
+	  good_tcp_udp0 |= is_udp0 && udp0->checksum == 0;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 1);
+
+	  /* Verify UDP length. */
+	  ip_len0 = clib_net_to_host_u16 (ip0->length);
+	  udp_len0 = clib_net_to_host_u16 (udp0->length);
+
+	  len_diff0 = ip_len0 - udp_len0;
+
+	  len_diff0 = is_udp0 ? len_diff0 : 0;
+
+	  if (PREDICT_FALSE (!(is_tcp_udp0 & good_tcp_udp0)))
+	    {
+	      if (is_tcp_udp0)
+		{
+		  if (is_tcp_udp0
+		      && !(flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED))
+		    flags0 = ip4_tcp_udp_validate_checksum (vm, p0);
+		  good_tcp_udp0 =
+		    (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+		  good_tcp_udp0 |= is_udp0 && udp0->checksum == 0;
+		}
+	    }
+
+	  good_tcp_udp0 &= len_diff0 >= 0;
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 2);
+
+	  error0 = IP4_ERROR_UNKNOWN_PROTOCOL;
+
+	  error0 = len_diff0 < 0 ? IP4_ERROR_UDP_LENGTH : error0;
+
+	  ASSERT (IP4_ERROR_TCP_CHECKSUM + 1 == IP4_ERROR_UDP_CHECKSUM);
+	  error0 = (is_tcp_udp0 && !good_tcp_udp0
+		    ? IP4_ERROR_TCP_CHECKSUM + is_udp0 : error0);
+
+	  leaf0 =
+	    ip4_fib_mtrie_lookup_step (mtrie0, leaf0, &ip0->src_address, 3);
+	  leaf0 =
+	    (leaf0 ==
+	     IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie0->default_leaf : leaf0);
+
+	  lbi0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = lbi0;
+
+	  lb0 = load_balance_get (lbi0);
+	  dpo0 = load_balance_get_bucket_i (lb0, 0);
+
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
+	    vnet_buffer (p0)->ip.adj_index[VLIB_RX] = lbi0;
+
+	  error0 = ((error0 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     dpo0->dpoi_type == DPO_RECEIVE) ?
+		    IP4_ERROR_SPOOFED_LOCAL_PACKETS : error0);
+	  error0 = ((error0 == IP4_ERROR_UNKNOWN_PROTOCOL &&
+		     !fib_urpf_check_size (lb0->lb_urpf) &&
+		     ip0->dst_address.as_u32 != 0xFFFFFFFF)
+		    ? IP4_ERROR_SRC_LOOKUP_MISS : error0);
+
+	  next0 = lm->local_next_by_ip_protocol[proto0];
+
+	  next0 =
+	    error0 != IP4_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next0;
+
+	  p0->error = error0 ? error_node->errors[error0] : 0;
+
+	  if (PREDICT_FALSE (next0 != next_index))
+	    {
+	      n_left_to_next += 1;
+	      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+
+	      next_index = next0;
+	      vlib_get_next_frame (vm, node, next_index, to_next,
+				   n_left_to_next);
+	      to_next[0] = pi0;
+	      to_next += 1;
+	      n_left_to_next -= 1;
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (ip4_local_node, static) =
+{
+  .function = ip4_local,.name = "ip4-local",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_next_nodes =
+    IP_LOCAL_N_NEXT,.next_nodes =
+  {
+  [IP_LOCAL_NEXT_DROP] = "error-drop",
+      [IP_LOCAL_NEXT_PUNT] = "error-punt",
+      [IP_LOCAL_NEXT_UDP_LOOKUP] = "ip4-udp-lookup",
+      [IP_LOCAL_NEXT_ICMP] = "ip4-icmp-input",}
+,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_local_node, ip4_local);
+
+void
+ip4_register_protocol (u32 protocol, u32 node_index)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+
+  ASSERT (protocol < ARRAY_LEN (lm->local_next_by_ip_protocol));
+  lm->local_next_by_ip_protocol[protocol] =
+    vlib_node_add_next (vm, ip4_local_node.index, node_index);
+}
+
+static clib_error_t *
+show_ip_local_command_fn (vlib_main_t * vm,
+			  unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  int i;
+
+  vlib_cli_output (vm, "Protocols handled by ip4_local");
+  for (i = 0; i < ARRAY_LEN (lm->local_next_by_ip_protocol); i++)
+    {
+      if (lm->local_next_by_ip_protocol[i] != IP_LOCAL_NEXT_PUNT)
+	vlib_cli_output (vm, "%d", i);
+    }
+  return 0;
+}
+
+
+
+/*?
+ * Display the set of protocols handled by the local IPv4 stack.
+ *
+ * @cliexpar
+ * Example of how to display local protocol table:
+ * @cliexstart{show ip local}
+ * Protocols handled by ip4_local
+ * 1
+ * 17
+ * 47
+ * @cliexend
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_ip_local, static) =
+{
+  .path = "show ip local",
+  .function = show_ip_local_command_fn,
+  .short_help = "show ip local",
+};
+/* *INDENT-ON* */
+
+always_inline uword
+ip4_arp_inline (vlib_main_t * vm,
+		vlib_node_runtime_t * node,
+		vlib_frame_t * frame, int is_glean)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  ip4_main_t *im = &ip4_main;
+  ip_lookup_main_t *lm = &im->lookup_main;
+  u32 *from, *to_next_drop;
+  uword n_left_from, n_left_to_next_drop, next_index;
+  static f64 time_last_seed_change = -1e100;
+  static u32 hash_seeds[3];
+  static uword hash_bitmap[256 / BITS (uword)];
+  f64 time_now;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  time_now = vlib_time_now (vm);
+  if (time_now - time_last_seed_change > 1e-3)
+    {
+      uword i;
+      u32 *r = clib_random_buffer_get_data (&vm->random_buffer,
+					    sizeof (hash_seeds));
+      for (i = 0; i < ARRAY_LEN (hash_seeds); i++)
+	hash_seeds[i] = r[i];
+
+      /* Mark all hash keys as been no-seen before. */
+      for (i = 0; i < ARRAY_LEN (hash_bitmap); i++)
+	hash_bitmap[i] = 0;
+
+      time_last_seed_change = time_now;
+    }
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+  if (next_index == IP4_ARP_NEXT_DROP)
+    next_index = IP4_ARP_N_NEXT;	/* point to first interface */
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, IP4_ARP_NEXT_DROP,
+			   to_next_drop, n_left_to_next_drop);
+
+      while (n_left_from > 0 && n_left_to_next_drop > 0)
+	{
+	  u32 pi0, adj_index0, a0, b0, c0, m0, sw_if_index0, drop0;
+	  ip_adjacency_t *adj0;
+	  vlib_buffer_t *p0;
+	  ip4_header_t *ip0;
+	  uword bm0;
+
+	  pi0 = from[0];
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+	  adj0 = ip_get_adjacency (lm, adj_index0);
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  a0 = hash_seeds[0];
+	  b0 = hash_seeds[1];
+	  c0 = hash_seeds[2];
+
+	  sw_if_index0 = adj0->rewrite_header.sw_if_index;
+	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
+
+	  if (is_glean)
+	    {
+	      /*
+	       * this is the Glean case, so we are ARPing for the
+	       * packet's destination
+	       */
+	      a0 ^= ip0->dst_address.data_u32;
+	    }
+	  else
+	    {
+	      a0 ^= adj0->sub_type.nbr.next_hop.ip4.data_u32;
+	    }
+	  b0 ^= sw_if_index0;
+
+	  hash_v3_finalize32 (a0, b0, c0);
+
+	  c0 &= BITS (hash_bitmap) - 1;
+	  c0 = c0 / BITS (uword);
+	  m0 = (uword) 1 << (c0 % BITS (uword));
+
+	  bm0 = hash_bitmap[c0];
+	  drop0 = (bm0 & m0) != 0;
+
+	  /* Mark it as seen. */
+	  hash_bitmap[c0] = bm0 | m0;
+
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next_drop[0] = pi0;
+	  to_next_drop += 1;
+	  n_left_to_next_drop -= 1;
+
+	  p0->error =
+	    node->errors[drop0 ? IP4_ARP_ERROR_DROP :
+			 IP4_ARP_ERROR_REQUEST_SENT];
+
+	  /*
+	   * the adj has been updated to a rewrite but the node the DPO that got
+	   * us here hasn't - yet. no big deal. we'll drop while we wait.
+	   */
+	  if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
+	    continue;
+
+	  if (drop0)
+	    continue;
+
+	  /*
+	   * Can happen if the control-plane is programming tables
+	   * with traffic flowing; at least that's today's lame excuse.
+	   */
+	  if ((is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_GLEAN) ||
+	      (!is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_ARP))
+	    {
+	      p0->error = node->errors[IP4_ARP_ERROR_NON_ARP_ADJ];
+	    }
+	  else
+	    /* Send ARP request. */
+	    {
+	      u32 bi0 = 0;
+	      vlib_buffer_t *b0;
+	      ethernet_arp_header_t *h0;
+	      vnet_hw_interface_t *hw_if0;
+
+	      h0 =
+		vlib_packet_template_get_packet (vm,
+						 &im->ip4_arp_request_packet_template,
+						 &bi0);
+
+	      /* Add rewrite/encap string for ARP packet. */
+	      vnet_rewrite_one_header (adj0[0], h0,
+				       sizeof (ethernet_header_t));
+
+	      hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
+
+	      /* Src ethernet address in ARP header. */
+	      clib_memcpy (h0->ip4_over_ethernet[0].ethernet,
+			   hw_if0->hw_address,
+			   sizeof (h0->ip4_over_ethernet[0].ethernet));
+
+	      if (is_glean)
+		{
+		  /* The interface's source address is stashed in the Glean Adj */
+		  h0->ip4_over_ethernet[0].ip4 =
+		    adj0->sub_type.glean.receive_addr.ip4;
+
+		  /* Copy in destination address we are requesting. This is the
+		   * glean case, so it's the packet's destination.*/
+		  h0->ip4_over_ethernet[1].ip4.data_u32 =
+		    ip0->dst_address.data_u32;
+		}
+	      else
+		{
+		  /* Src IP address in ARP header. */
+		  if (ip4_src_address_for_packet (lm, sw_if_index0,
+						  &h0->
+						  ip4_over_ethernet[0].ip4))
+		    {
+		      /* No source address available */
+		      p0->error =
+			node->errors[IP4_ARP_ERROR_NO_SOURCE_ADDRESS];
+		      vlib_buffer_free (vm, &bi0, 1);
+		      continue;
+		    }
+
+		  /* Copy in destination address we are requesting from the
+		     incomplete adj */
+		  h0->ip4_over_ethernet[1].ip4.data_u32 =
+		    adj0->sub_type.nbr.next_hop.ip4.as_u32;
+		}
+
+	      vlib_buffer_copy_trace_flag (vm, p0, bi0);
+	      b0 = vlib_get_buffer (vm, bi0);
+	      vnet_buffer (b0)->sw_if_index[VLIB_TX] = sw_if_index0;
+
+	      vlib_buffer_advance (b0, -adj0->rewrite_header.data_bytes);
+
+	      vlib_set_next_frame_buffer (vm, node,
+					  adj0->rewrite_header.next_index,
+					  bi0);
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, IP4_ARP_NEXT_DROP, n_left_to_next_drop);
+    }
+
+  return frame->n_vectors;
+}
+
+static uword
+ip4_arp (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return (ip4_arp_inline (vm, node, frame, 0));
+}
+
+static uword
+ip4_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return (ip4_arp_inline (vm, node, frame, 1));
+}
+
+static char *ip4_arp_error_strings[] = {
+  [IP4_ARP_ERROR_DROP] = "address overflow drops",
+  [IP4_ARP_ERROR_REQUEST_SENT] = "ARP requests sent",
+  [IP4_ARP_ERROR_NON_ARP_ADJ] = "ARPs to non-ARP adjacencies",
+  [IP4_ARP_ERROR_REPLICATE_DROP] = "ARP replication completed",
+  [IP4_ARP_ERROR_REPLICATE_FAIL] = "ARP replication failed",
+  [IP4_ARP_ERROR_NO_SOURCE_ADDRESS] = "no source address for ARP request",
+};
+
+VLIB_REGISTER_NODE (ip4_arp_node) =
+{
+  .function = ip4_arp,.name = "ip4-arp",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_errors =
+    ARRAY_LEN (ip4_arp_error_strings),.error_strings =
+    ip4_arp_error_strings,.n_next_nodes = IP4_ARP_N_NEXT,.next_nodes =
+  {
+  [IP4_ARP_NEXT_DROP] = "error-drop",}
+,};
+
+VLIB_REGISTER_NODE (ip4_glean_node) =
+{
+  .function = ip4_glean,.name = "ip4-glean",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_errors =
+    ARRAY_LEN (ip4_arp_error_strings),.error_strings =
+    ip4_arp_error_strings,.n_next_nodes = IP4_ARP_N_NEXT,.next_nodes =
+  {
+  [IP4_ARP_NEXT_DROP] = "error-drop",}
+,};
+
+#define foreach_notrace_ip4_arp_error           \
+_(DROP)                                         \
+_(REQUEST_SENT)                                 \
+_(REPLICATE_DROP)                               \
+_(REPLICATE_FAIL)
+
+clib_error_t *
+arp_notrace_init (vlib_main_t * vm)
+{
+  vlib_node_runtime_t *rt = vlib_node_get_runtime (vm, ip4_arp_node.index);
+
+  /* don't trace ARP request packets */
+#define _(a)                                    \
+    vnet_pcap_drop_trace_filter_add_del         \
+        (rt->errors[IP4_ARP_ERROR_##a],         \
+         1 /* is_add */);
+  foreach_notrace_ip4_arp_error;
+#undef _
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (arp_notrace_init);
+
+
+/* Send an ARP request to see if given destination is reachable on given interface. */
+clib_error_t *
+ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  ip4_main_t *im = &ip4_main;
+  ethernet_arp_header_t *h;
+  ip4_address_t *src;
+  ip_interface_address_t *ia;
+  ip_adjacency_t *adj;
+  vnet_hw_interface_t *hi;
+  vnet_sw_interface_t *si;
+  vlib_buffer_t *b;
+  u32 bi = 0;
+
+  si = vnet_get_sw_interface (vnm, sw_if_index);
+
+  if (!(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP))
+    {
+      return clib_error_return (0, "%U: interface %U down",
+				format_ip4_address, dst,
+				format_vnet_sw_if_index_name, vnm,
+				sw_if_index);
+    }
+
+  src =
+    ip4_interface_address_matching_destination (im, dst, sw_if_index, &ia);
+  if (!src)
+    {
+      vnm->api_errno = VNET_API_ERROR_NO_MATCHING_INTERFACE;
+      return clib_error_return
+	(0, "no matching interface address for destination %U (interface %U)",
+	 format_ip4_address, dst,
+	 format_vnet_sw_if_index_name, vnm, sw_if_index);
+    }
+
+  adj = ip_get_adjacency (&im->lookup_main, ia->neighbor_probe_adj_index);
+
+  h =
+    vlib_packet_template_get_packet (vm, &im->ip4_arp_request_packet_template,
+				     &bi);
+
+  hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
+
+  clib_memcpy (h->ip4_over_ethernet[0].ethernet, hi->hw_address,
+	       sizeof (h->ip4_over_ethernet[0].ethernet));
+
+  h->ip4_over_ethernet[0].ip4 = src[0];
+  h->ip4_over_ethernet[1].ip4 = dst[0];
+
+  b = vlib_get_buffer (vm, bi);
+  vnet_buffer (b)->sw_if_index[VLIB_RX] =
+    vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
+
+  /* Add encapsulation string for software interface (e.g. ethernet header). */
+  vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
+  vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);
+
+  {
+    vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
+    u32 *to_next = vlib_frame_vector_args (f);
+    to_next[0] = bi;
+    f->n_vectors = 1;
+    vlib_put_frame_to_node (vm, hi->output_node_index, f);
+  }
+
+  return /* no error */ 0;
+}
+
+typedef enum
+{
+  IP4_REWRITE_NEXT_DROP,
+  IP4_REWRITE_NEXT_ICMP_ERROR,
+} ip4_rewrite_next_t;
+
+always_inline uword
+ip4_rewrite_inline (vlib_main_t * vm,
+		    vlib_node_runtime_t * node,
+		    vlib_frame_t * frame, int is_midchain)
+{
+  ip_lookup_main_t *lm = &ip4_main.lookup_main;
+  u32 *from = vlib_frame_vector_args (frame);
+  u32 n_left_from, n_left_to_next, *to_next, next_index;
+  vlib_node_runtime_t *error_node =
+    vlib_node_get_runtime (vm, ip4_input_node.index);
+
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+  u32 cpu_index = os_get_cpu_number ();
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  ip_adjacency_t *adj0, *adj1;
+	  vlib_buffer_t *p0, *p1;
+	  ip4_header_t *ip0, *ip1;
+	  u32 pi0, rw_len0, next0, error0, checksum0, adj_index0;
+	  u32 pi1, rw_len1, next1, error1, checksum1, adj_index1;
+	  u32 tx_sw_if_index0, tx_sw_if_index1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, STORE);
+	    vlib_prefetch_buffer_header (p3, STORE);
+
+	    CLIB_PREFETCH (p2->data, sizeof (ip0[0]), STORE);
+	    CLIB_PREFETCH (p3->data, sizeof (ip0[0]), STORE);
+	  }
+
+	  pi0 = to_next[0] = from[0];
+	  pi1 = to_next[1] = from[1];
+
+	  from += 2;
+	  n_left_from -= 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  p1 = vlib_get_buffer (vm, pi1);
+
+	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+	  adj_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];
+
+	  /* We should never rewrite a pkt using the MISS adjacency */
+	  ASSERT (adj_index0 && adj_index1);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  ip1 = vlib_buffer_get_current (p1);
+
+	  error0 = error1 = IP4_ERROR_NONE;
+	  next0 = next1 = IP4_REWRITE_NEXT_DROP;
+
+	  /* Decrement TTL & update checksum.
+	     Works either endian, so no need for byte swap. */
+	  if (PREDICT_TRUE (!(p0->flags & VNET_BUFFER_LOCALLY_ORIGINATED)))
+	    {
+	      i32 ttl0 = ip0->ttl;
+
+	      /* Input node should have reject packets with ttl 0. */
+	      ASSERT (ip0->ttl > 0);
+
+	      checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
+	      checksum0 += checksum0 >= 0xffff;
+
+	      ip0->checksum = checksum0;
+	      ttl0 -= 1;
+	      ip0->ttl = ttl0;
+
+	      /*
+	       * If the ttl drops below 1 when forwarding, generate
+	       * an ICMP response.
+	       */
+	      if (PREDICT_FALSE (ttl0 <= 0))
+		{
+		  error0 = IP4_ERROR_TIME_EXPIRED;
+		  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+		  icmp4_error_set_vnet_buffer (p0, ICMP4_time_exceeded,
+					       ICMP4_time_exceeded_ttl_exceeded_in_transit,
+					       0);
+		  next0 = IP4_REWRITE_NEXT_ICMP_ERROR;
+		}
+
+	      /* Verify checksum. */
+	      ASSERT (ip0->checksum == ip4_header_checksum (ip0));
+	    }
+	  else
+	    {
+	      p0->flags &= ~VNET_BUFFER_LOCALLY_ORIGINATED;
+	    }
+	  if (PREDICT_TRUE (!(p1->flags & VNET_BUFFER_LOCALLY_ORIGINATED)))
+	    {
+	      i32 ttl1 = ip1->ttl;
+
+	      /* Input node should have reject packets with ttl 0. */
+	      ASSERT (ip1->ttl > 0);
+
+	      checksum1 = ip1->checksum + clib_host_to_net_u16 (0x0100);
+	      checksum1 += checksum1 >= 0xffff;
+
+	      ip1->checksum = checksum1;
+	      ttl1 -= 1;
+	      ip1->ttl = ttl1;
+
+	      /*
+	       * If the ttl drops below 1 when forwarding, generate
+	       * an ICMP response.
+	       */
+	      if (PREDICT_FALSE (ttl1 <= 0))
+		{
+		  error1 = IP4_ERROR_TIME_EXPIRED;
+		  vnet_buffer (p1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+		  icmp4_error_set_vnet_buffer (p1, ICMP4_time_exceeded,
+					       ICMP4_time_exceeded_ttl_exceeded_in_transit,
+					       0);
+		  next1 = IP4_REWRITE_NEXT_ICMP_ERROR;
+		}
+
+	      /* Verify checksum. */
+	      ASSERT (ip0->checksum == ip4_header_checksum (ip0));
+	      ASSERT (ip1->checksum == ip4_header_checksum (ip1));
+	    }
+	  else
+	    {
+	      p1->flags &= ~VNET_BUFFER_LOCALLY_ORIGINATED;
+	    }
+
+	  /* Rewrite packet header and updates lengths. */
+	  adj0 = ip_get_adjacency (lm, adj_index0);
+	  adj1 = ip_get_adjacency (lm, adj_index1);
+
+	  /* Worth pipelining. No guarantee that adj0,1 are hot... */
+	  rw_len0 = adj0[0].rewrite_header.data_bytes;
+	  rw_len1 = adj1[0].rewrite_header.data_bytes;
+	  vnet_buffer (p0)->ip.save_rewrite_length = rw_len0;
+	  vnet_buffer (p1)->ip.save_rewrite_length = rw_len1;
+
+	  /* Check MTU of outgoing interface. */
+	  error0 =
+	    (vlib_buffer_length_in_chain (vm, p0) >
+	     adj0[0].
+	     rewrite_header.max_l3_packet_bytes ? IP4_ERROR_MTU_EXCEEDED :
+	     error0);
+	  error1 =
+	    (vlib_buffer_length_in_chain (vm, p1) >
+	     adj1[0].
+	     rewrite_header.max_l3_packet_bytes ? IP4_ERROR_MTU_EXCEEDED :
+	     error1);
+
+	  /*
+	   * We've already accounted for an ethernet_header_t elsewhere
+	   */
+	  if (PREDICT_FALSE (rw_len0 > sizeof (ethernet_header_t)))
+	    vlib_increment_combined_counter
+	      (&adjacency_counters, cpu_index, adj_index0,
+	       /* packet increment */ 0,
+	       /* byte increment */ rw_len0 - sizeof (ethernet_header_t));
+
+	  if (PREDICT_FALSE (rw_len1 > sizeof (ethernet_header_t)))
+	    vlib_increment_combined_counter
+	      (&adjacency_counters, cpu_index, adj_index1,
+	       /* packet increment */ 0,
+	       /* byte increment */ rw_len1 - sizeof (ethernet_header_t));
+
+	  /* Don't adjust the buffer for ttl issue; icmp-error node wants
+	   * to see the IP headerr */
+	  if (PREDICT_TRUE (error0 == IP4_ERROR_NONE))
+	    {
+	      next0 = adj0[0].rewrite_header.next_index;
+	      p0->current_data -= rw_len0;
+	      p0->current_length += rw_len0;
+	      tx_sw_if_index0 = adj0[0].rewrite_header.sw_if_index;
+	      vnet_buffer (p0)->sw_if_index[VLIB_TX] = tx_sw_if_index0;
+
+	      vnet_feature_arc_start (lm->output_feature_arc_index,
+				      tx_sw_if_index0, &next0, p0);
+	    }
+	  if (PREDICT_TRUE (error1 == IP4_ERROR_NONE))
+	    {
+	      next1 = adj1[0].rewrite_header.next_index;
+	      p1->current_data -= rw_len1;
+	      p1->current_length += rw_len1;
+
+	      tx_sw_if_index1 = adj1[0].rewrite_header.sw_if_index;
+	      vnet_buffer (p1)->sw_if_index[VLIB_TX] = tx_sw_if_index1;
+
+	      vnet_feature_arc_start (lm->output_feature_arc_index,
+				      tx_sw_if_index1, &next1, p1);
+	    }
+
+	  /* Guess we are only writing on simple Ethernet header. */
+	  vnet_rewrite_two_headers (adj0[0], adj1[0],
+				    ip0, ip1, sizeof (ethernet_header_t));
+
+	  if (is_midchain)
+	    {
+	      adj0->sub_type.midchain.fixup_func (vm, adj0, p0);
+	      adj1->sub_type.midchain.fixup_func (vm, adj1, p1);
+	    }
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   pi0, pi1, next0, next1);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  ip_adjacency_t *adj0;
+	  vlib_buffer_t *p0;
+	  ip4_header_t *ip0;
+	  u32 pi0, rw_len0, adj_index0, next0, error0, checksum0;
+	  u32 tx_sw_if_index0;
+
+	  pi0 = to_next[0] = from[0];
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
+
+	  /* We should never rewrite a pkt using the MISS adjacency */
+	  ASSERT (adj_index0);
+
+	  adj0 = ip_get_adjacency (lm, adj_index0);
+
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  error0 = IP4_ERROR_NONE;
+	  next0 = IP4_REWRITE_NEXT_DROP;	/* drop on error */
+
+	  /* Decrement TTL & update checksum. */
+	  if (PREDICT_TRUE (!(p0->flags & VNET_BUFFER_LOCALLY_ORIGINATED)))
+	    {
+	      i32 ttl0 = ip0->ttl;
+
+	      checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
+
+	      checksum0 += checksum0 >= 0xffff;
+
+	      ip0->checksum = checksum0;
+
+	      ASSERT (ip0->ttl > 0);
+
+	      ttl0 -= 1;
+
+	      ip0->ttl = ttl0;
+
+	      ASSERT (ip0->checksum == ip4_header_checksum (ip0));
+
+	      if (PREDICT_FALSE (ttl0 <= 0))
+		{
+		  /*
+		   * If the ttl drops below 1 when forwarding, generate
+		   * an ICMP response.
+		   */
+		  error0 = IP4_ERROR_TIME_EXPIRED;
+		  next0 = IP4_REWRITE_NEXT_ICMP_ERROR;
+		  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+		  icmp4_error_set_vnet_buffer (p0, ICMP4_time_exceeded,
+					       ICMP4_time_exceeded_ttl_exceeded_in_transit,
+					       0);
+		}
+	    }
+	  else
+	    {
+	      p0->flags &= ~VNET_BUFFER_LOCALLY_ORIGINATED;
+	    }
+
+	  /* Guess we are only writing on simple Ethernet header. */
+	  vnet_rewrite_one_header (adj0[0], ip0, sizeof (ethernet_header_t));
+
+	  /* Update packet buffer attributes/set output interface. */
+	  rw_len0 = adj0[0].rewrite_header.data_bytes;
+	  vnet_buffer (p0)->ip.save_rewrite_length = rw_len0;
+
+	  if (PREDICT_FALSE (rw_len0 > sizeof (ethernet_header_t)))
+	    vlib_increment_combined_counter
+	      (&adjacency_counters, cpu_index, adj_index0,
+	       /* packet increment */ 0,
+	       /* byte increment */ rw_len0 - sizeof (ethernet_header_t));
+
+	  /* Check MTU of outgoing interface. */
+	  error0 = (vlib_buffer_length_in_chain (vm, p0)
+		    > adj0[0].rewrite_header.max_l3_packet_bytes
+		    ? IP4_ERROR_MTU_EXCEEDED : error0);
+
+	  p0->error = error_node->errors[error0];
+
+	  /* Don't adjust the buffer for ttl issue; icmp-error node wants
+	   * to see the IP headerr */
+	  if (PREDICT_TRUE (error0 == IP4_ERROR_NONE))
+	    {
+	      p0->current_data -= rw_len0;
+	      p0->current_length += rw_len0;
+	      tx_sw_if_index0 = adj0[0].rewrite_header.sw_if_index;
+
+	      vnet_buffer (p0)->sw_if_index[VLIB_TX] = tx_sw_if_index0;
+	      next0 = adj0[0].rewrite_header.next_index;
+
+	      if (is_midchain)
+		{
+		  adj0->sub_type.midchain.fixup_func (vm, adj0, p0);
+		}
+
+	      vnet_feature_arc_start (lm->output_feature_arc_index,
+				      tx_sw_if_index0, &next0, p0);
+
+	    }
+
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   pi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  /* Need to do trace after rewrites to pick up new packet data. */
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  return frame->n_vectors;
+}
+
+
+/** @brief IPv4 rewrite node.
+    @node ip4-rewrite
+
+    This is the IPv4 transit-rewrite node: decrement TTL, fix the ipv4
+    header checksum, fetch the ip adjacency, check the outbound mtu,
+    apply the adjacency rewrite, and send pkts to the adjacency
+    rewrite header's rewrite_next_index.
+
+    @param vm vlib_main_t corresponding to the current thread
+    @param node vlib_node_runtime_t
+    @param frame vlib_frame_t whose contents should be dispatched
+
+    @par Graph mechanics: buffer metadata, next index usage
+
+    @em Uses:
+    - <code>vnet_buffer(b)->ip.adj_index[VLIB_TX]</code>
+        - the rewrite adjacency index
+    - <code>adj->lookup_next_index</code>
+        - Must be IP_LOOKUP_NEXT_REWRITE or IP_LOOKUP_NEXT_ARP, otherwise
+          the packet will be dropped.
+    - <code>adj->rewrite_header</code>
+        - Rewrite string length, rewrite string, next_index
+
+    @em Sets:
+    - <code>b->current_data, b->current_length</code>
+        - Updated net of applying the rewrite string
+
+    <em>Next Indices:</em>
+    - <code> adj->rewrite_header.next_index </code>
+      or @c error-drop
+*/
+static uword
+ip4_rewrite (vlib_main_t * vm,
+	     vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return ip4_rewrite_inline (vm, node, frame, 0);
+}
+
+static uword
+ip4_midchain (vlib_main_t * vm,
+	      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return ip4_rewrite_inline (vm, node, frame, 1);
+}
+
+
+VLIB_REGISTER_NODE (ip4_rewrite_node) =
+{
+  .function = ip4_rewrite,.name = "ip4-rewrite",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_rewrite_trace,.n_next_nodes =
+    2,.next_nodes =
+  {
+  [IP4_REWRITE_NEXT_DROP] = "error-drop",
+      [IP4_REWRITE_NEXT_ICMP_ERROR] = "ip4-icmp-error",}
+,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_rewrite_node, ip4_rewrite);
+
+VLIB_REGISTER_NODE (ip4_midchain_node) =
+{
+.function = ip4_midchain,.name = "ip4-midchain",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.sibling_of =
+    "ip4-rewrite",};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_midchain_node, ip4_midchain);
+
+static clib_error_t *
+add_del_interface_table (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, table_id;
+
+  sw_if_index = ~0;
+
+  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", &table_id))
+    ;
+  else
+    {
+      error = clib_error_return (0, "expected table id `%U'",
+				 format_unformat_error, input);
+      goto done;
+    }
+
+  {
+    ip4_main_t *im = &ip4_main;
+    u32 fib_index;
+
+    fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
+						   table_id);
+
+    //
+    // FIXME-LATER
+    //  changing an interface's table has consequences for any connecteds
+    //  and adj-fibs already installed.
+    //
+    vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
+    im->fib_index_by_sw_if_index[sw_if_index] = fib_index;
+  }
+
+done:
+  return error;
+}
+
+/*?
+ * Place the indicated interface into the supplied IPv4 FIB table (also known
+ * as a VRF). If the FIB table does not exist, this command creates it. To
+ * display the current IPv4 FIB table, use the command '<em>show ip fib</em>'.
+ * FIB table will only be displayed if a route has been added to the table, or
+ * an IP Address is assigned to an interface in the table (which adds a route
+ * automatically).
+ *
+ * @note IP addresses added after setting the interface IP table end up in
+ * the indicated FIB table. If the IP address is added prior to adding the
+ * interface to the FIB table, it will NOT be part of the FIB table. Predictable
+ * but potentially counter-intuitive results occur if you provision interface
+ * addresses in multiple FIBs. Upon RX, packets will be processed in the last
+ * IP table ID provisioned. It might be marginally useful to evade source RPF
+ * drops to put an interface address into multiple FIBs.
+ *
+ * @cliexpar
+ * Example of how to add an interface to an IPv4 FIB table (where 2 is the table-id):
+ * @cliexcmd{set interface ip table GigabitEthernet2/0/0 2}
+ ?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (set_interface_ip_table_command, static) =
+{
+  .path = "set interface ip table",
+  .function = add_del_interface_table,
+  .short_help = "set interface ip table <interface> <table-id>",
+};
+/* *INDENT-ON* */
+
+
+static uword
+ip4_lookup_multicast (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  ip4_main_t *im = &ip4_main;
+  vlib_combined_counter_main_t *cm = &load_balance_main.lbm_to_counters;
+  u32 n_left_from, n_left_to_next, *from, *to_next;
+  ip_lookup_next_t next;
+  u32 cpu_index = os_get_cpu_number ();
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  vlib_buffer_t *p0, *p1;
+	  u32 pi0, pi1, lb_index0, lb_index1, wrong_next;
+	  ip_lookup_next_t next0, next1;
+	  ip4_header_t *ip0, *ip1;
+	  u32 fib_index0, fib_index1;
+	  const dpo_id_t *dpo0, *dpo1;
+	  const load_balance_t *lb0, *lb1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data, sizeof (ip0[0]), LOAD);
+	    CLIB_PREFETCH (p3->data, sizeof (ip0[0]), LOAD);
+	  }
+
+	  pi0 = to_next[0] = from[0];
+	  pi1 = to_next[1] = from[1];
+
+	  p0 = vlib_get_buffer (vm, pi0);
+	  p1 = vlib_get_buffer (vm, pi1);
+
+	  ip0 = vlib_buffer_get_current (p0);
+	  ip1 = vlib_buffer_get_current (p1);
+
+	  fib_index0 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index1 =
+	    vec_elt (im->fib_index_by_sw_if_index,
+		     vnet_buffer (p1)->sw_if_index[VLIB_RX]);
+	  fib_index0 =
+	    (vnet_buffer (p0)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+	  fib_index1 =
+	    (vnet_buffer (p1)->sw_if_index[VLIB_TX] ==
+	     (u32) ~ 0) ? fib_index1 : vnet_buffer (p1)->sw_if_index[VLIB_TX];
+
+	  lb_index0 = ip4_fib_table_lookup_lb (ip4_fib_get (fib_index0),
+					       &ip0->dst_address);
+	  lb_index1 = ip4_fib_table_lookup_lb (ip4_fib_get (fib_index1),
+					       &ip1->dst_address);
+
+	  lb0 = load_balance_get (lb_index0);
+	  lb1 = load_balance_get (lb_index1);
+
+	  ASSERT (lb0->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb0->lb_n_buckets));
+	  ASSERT (lb1->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb1->lb_n_buckets));
+
+	  vnet_buffer (p0)->ip.flow_hash = ip4_compute_flow_hash
+	    (ip0, lb0->lb_hash_config);
+
+	  vnet_buffer (p1)->ip.flow_hash = ip4_compute_flow_hash
+	    (ip1, lb1->lb_hash_config);
+
+	  dpo0 = load_balance_get_bucket_i (lb0,
+					    (vnet_buffer (p0)->ip.flow_hash &
+					     (lb0->lb_n_buckets_minus_1)));
+	  dpo1 = load_balance_get_bucket_i (lb1,
+					    (vnet_buffer (p1)->ip.flow_hash &
+					     (lb1->lb_n_buckets_minus_1)));
+
+	  next0 = dpo0->dpoi_next_node;
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+	  next1 = dpo1->dpoi_next_node;
+	  vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
+
+	  if (1)		/* $$$$$$ HACK FIXME */
+	    vlib_increment_combined_counter
+	      (cm, cpu_index, lb_index0, 1,
+	       vlib_buffer_length_in_chain (vm, p0));
+	  if (1)		/* $$$$$$ HACK FIXME */
+	    vlib_increment_combined_counter
+	      (cm, cpu_index, lb_index1, 1,
+	       vlib_buffer_length_in_chain (vm, p1));
+
+	  from += 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+	  n_left_from -= 2;
+
+	  wrong_next = (next0 != next) + 2 * (next1 != next);
+	  if (PREDICT_FALSE (wrong_next != 0))
+	    {
+	      switch (wrong_next)
+		{
+		case 1:
+		  /* A B A */
+		  to_next[-2] = pi1;
+		  to_next -= 1;
+		  n_left_to_next += 1;
+		  vlib_set_next_frame_buffer (vm, node, next0, pi0);
+		  break;
+
+		case 2:
+		  /* A A B */
+		  to_next -= 1;
+		  n_left_to_next += 1;
+		  vlib_set_next_frame_buffer (vm, node, next1, pi1);
+		  break;
+
+		case 3:
+		  /* A B C */
+		  to_next -= 2;
+		  n_left_to_next += 2;
+		  vlib_set_next_frame_buffer (vm, node, next0, pi0);
+		  vlib_set_next_frame_buffer (vm, node, next1, pi1);
+		  if (next0 == next1)
+		    {
+		      /* A B B */
+		      vlib_put_next_frame (vm, node, next, n_left_to_next);
+		      next = next1;
+		      vlib_get_next_frame (vm, node, next, to_next,
+					   n_left_to_next);
+		    }
+		}
+	    }
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *p0;
+	  ip4_header_t *ip0;
+	  u32 pi0, lb_index0;
+	  ip_lookup_next_t next0;
+	  u32 fib_index0;
+	  const dpo_id_t *dpo0;
+	  const load_balance_t *lb0;
+
+	  pi0 = from[0];
+	  to_next[0] = pi0;
+
+	  p0 = vlib_get_buffer (vm, pi0);
+
+	  ip0 = vlib_buffer_get_current (p0);
+
+	  fib_index0 = vec_elt (im->fib_index_by_sw_if_index,
+				vnet_buffer (p0)->sw_if_index[VLIB_RX]);
+	  fib_index0 = (vnet_buffer (p0)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	    fib_index0 : vnet_buffer (p0)->sw_if_index[VLIB_TX];
+
+	  lb_index0 = ip4_fib_table_lookup_lb (ip4_fib_get (fib_index0),
+					       &ip0->dst_address);
+
+	  lb0 = load_balance_get (lb_index0);
+
+	  ASSERT (lb0->lb_n_buckets > 0);
+	  ASSERT (is_pow2 (lb0->lb_n_buckets));
+
+	  vnet_buffer (p0)->ip.flow_hash = ip4_compute_flow_hash
+	    (ip0, lb0->lb_hash_config);
+
+	  dpo0 = load_balance_get_bucket_i (lb0,
+					    (vnet_buffer (p0)->ip.flow_hash &
+					     (lb0->lb_n_buckets_minus_1)));
+
+	  next0 = dpo0->dpoi_next_node;
+	  vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
+
+	  if (1)		/* $$$$$$ HACK FIXME */
+	    vlib_increment_combined_counter
+	      (cm, cpu_index, lb_index0, 1,
+	       vlib_buffer_length_in_chain (vm, p0));
+
+	  from += 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+	  n_left_from -= 1;
+
+	  if (PREDICT_FALSE (next0 != next))
+	    {
+	      n_left_to_next += 1;
+	      vlib_put_next_frame (vm, node, next, n_left_to_next);
+	      next = next0;
+	      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
+	      to_next[0] = pi0;
+	      to_next += 1;
+	      n_left_to_next -= 1;
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, next, n_left_to_next);
+    }
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (ip4_lookup_multicast_node, static) =
+{
+.function = ip4_lookup_multicast,.name =
+    "ip4-lookup-multicast",.vector_size = sizeof (u32),.sibling_of =
+    "ip4-lookup",.format_trace = format_ip4_lookup_trace,.n_next_nodes = 0,};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_lookup_multicast_node,
+			      ip4_lookup_multicast);
+
+VLIB_REGISTER_NODE (ip4_multicast_node, static) =
+{
+  .function = ip4_drop,.name = "ip4-multicast",.vector_size =
+    sizeof (u32),.format_trace = format_ip4_forward_next_trace,.n_next_nodes =
+    1,.next_nodes =
+  {
+  [0] = "error-drop",}
+,};
+
+int
+ip4_lookup_validate (ip4_address_t * a, u32 fib_index0)
+{
+  ip4_fib_mtrie_t *mtrie0;
+  ip4_fib_mtrie_leaf_t leaf0;
+  u32 lbi0;
+
+  mtrie0 = &ip4_fib_get (fib_index0)->mtrie;
+
+  leaf0 = IP4_FIB_MTRIE_LEAF_ROOT;
+  leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, a, 0);
+  leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, a, 1);
+  leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, a, 2);
+  leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, a, 3);
+
+  /* Handle default route. */
+  leaf0 = (leaf0 == IP4_FIB_MTRIE_LEAF_EMPTY ? mtrie0->default_leaf : leaf0);
+
+  lbi0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
+
+  return lbi0 == ip4_fib_table_lookup_lb (ip4_fib_get (fib_index0), a);
+}
+
+static clib_error_t *
+test_lookup_command_fn (vlib_main_t * vm,
+			unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  ip4_fib_t *fib;
+  u32 table_id = 0;
+  f64 count = 1;
+  u32 n;
+  int i;
+  ip4_address_t ip4_base_address;
+  u64 errors = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "table %d", &table_id))
+	{
+	  /* Make sure the entry exists. */
+	  fib = ip4_fib_get (table_id);
+	  if ((fib) && (fib->index != table_id))
+	    return clib_error_return (0, "<fib-index> %d does not exist",
+				      table_id);
+	}
+      else if (unformat (input, "count %f", &count))
+	;
+
+      else if (unformat (input, "%U",
+			 unformat_ip4_address, &ip4_base_address))
+	;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+
+  n = count;
+
+  for (i = 0; i < n; i++)
+    {
+      if (!ip4_lookup_validate (&ip4_base_address, table_id))
+	errors++;
+
+      ip4_base_address.as_u32 =
+	clib_host_to_net_u32 (1 +
+			      clib_net_to_host_u32 (ip4_base_address.as_u32));
+    }
+
+  if (errors)
+    vlib_cli_output (vm, "%llu errors out of %d lookups\n", errors, n);
+  else
+    vlib_cli_output (vm, "No errors in %d lookups\n", n);
+
+  return 0;
+}
+
+/*?
+ * Perform a lookup of an IPv4 Address (or range of addresses) in the
+ * given FIB table to determine if there is a conflict with the
+ * adjacency table. The fib-id can be determined by using the
+ * '<em>show ip fib</em>' command. If fib-id is not entered, default value
+ * of 0 is used.
+ *
+ * @todo This command uses fib-id, other commands use table-id (not
+ * just a name, they are different indexes). Would like to change this
+ * to table-id for consistency.
+ *
+ * @cliexpar
+ * Example of how to run the test lookup command:
+ * @cliexstart{test lookup 172.16.1.1 table 1 count 2}
+ * No errors in 2 lookups
+ * @cliexend
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (lookup_test_command, static) =
+{
+  .path = "test lookup",
+  .short_help = "test lookup <ipv4-addr> [table <fib-id>] [count <nn>]",
+  .function = test_lookup_command_fn,
+};
+/* *INDENT-ON* */
+
+int
+vnet_set_ip4_flow_hash (u32 table_id, u32 flow_hash_config)
+{
+  ip4_main_t *im4 = &ip4_main;
+  ip4_fib_t *fib;
+  uword *p = hash_get (im4->fib_index_by_table_id, table_id);
+
+  if (p == 0)
+    return VNET_API_ERROR_NO_SUCH_FIB;
+
+  fib = ip4_fib_get (p[0]);
+
+  fib->flow_hash_config = flow_hash_config;
+  return 0;
+}
+
+static clib_error_t *
+set_ip_flow_hash_command_fn (vlib_main_t * vm,
+			     unformat_input_t * input,
+			     vlib_cli_command_t * cmd)
+{
+  int matched = 0;
+  u32 table_id = 0;
+  u32 flow_hash_config = 0;
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "table %d", &table_id))
+	matched = 1;
+#define _(a,v) \
+    else if (unformat (input, #a)) { flow_hash_config |= v; matched=1;}
+      foreach_flow_hash_bit
+#undef _
+	else
+	break;
+    }
+
+  if (matched == 0)
+    return clib_error_return (0, "unknown input `%U'",
+			      format_unformat_error, input);
+
+  rv = vnet_set_ip4_flow_hash (table_id, flow_hash_config);
+  switch (rv)
+    {
+    case 0:
+      break;
+
+    case VNET_API_ERROR_NO_SUCH_FIB:
+      return clib_error_return (0, "no such FIB table %d", table_id);
+
+    default:
+      clib_warning ("BUG: illegal flow hash config 0x%x", flow_hash_config);
+      break;
+    }
+
+  return 0;
+}
+
+/*?
+ * Configure the set of IPv4 fields used by the flow hash.
+ *
+ * @cliexpar
+ * Example of how to set the flow hash on a given table:
+ * @cliexcmd{set ip flow-hash table 7 dst sport dport proto}
+ * Example of display the configured flow hash:
+ * @cliexstart{show ip fib}
+ * ipv4-VRF:0, fib_index 0, flow hash: src dst sport dport proto
+ * 0.0.0.0/0
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:0 buckets:1 uRPF:0 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 0.0.0.0/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:1 buckets:1 uRPF:1 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 224.0.0.0/8
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:3 buckets:1 uRPF:3 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 6.0.1.2/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:30 buckets:1 uRPF:29 to:[0:0]]
+ *     [0] [@3]: arp-ipv4: via 6.0.0.1 af_packet0
+ * 7.0.0.1/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:31 buckets:4 uRPF:30 to:[0:0]]
+ *     [0] [@3]: arp-ipv4: via 6.0.0.2 af_packet0
+ *     [1] [@3]: arp-ipv4: via 6.0.0.2 af_packet0
+ *     [2] [@3]: arp-ipv4: via 6.0.0.2 af_packet0
+ *     [3] [@3]: arp-ipv4: via 6.0.0.1 af_packet0
+ * 240.0.0.0/8
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:2 buckets:1 uRPF:2 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 255.255.255.255/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:4 buckets:1 uRPF:4 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * ipv4-VRF:7, fib_index 1, flow hash: dst sport dport proto
+ * 0.0.0.0/0
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:12 buckets:1 uRPF:11 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 0.0.0.0/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:13 buckets:1 uRPF:12 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 172.16.1.0/24
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:17 buckets:1 uRPF:16 to:[0:0]]
+ *     [0] [@4]: ipv4-glean: af_packet0
+ * 172.16.1.1/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:18 buckets:1 uRPF:17 to:[1:84]]
+ *     [0] [@2]: dpo-receive: 172.16.1.1 on af_packet0
+ * 172.16.1.2/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:21 buckets:1 uRPF:20 to:[0:0]]
+ *     [0] [@5]: ipv4 via 172.16.1.2 af_packet0: IP4: 02:fe:9e:70:7a:2b -> 26:a5:f6:9c:3a:36
+ * 172.16.2.0/24
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:19 buckets:1 uRPF:18 to:[0:0]]
+ *     [0] [@4]: ipv4-glean: af_packet1
+ * 172.16.2.1/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:20 buckets:1 uRPF:19 to:[0:0]]
+ *     [0] [@2]: dpo-receive: 172.16.2.1 on af_packet1
+ * 224.0.0.0/8
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:15 buckets:1 uRPF:14 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 240.0.0.0/8
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:14 buckets:1 uRPF:13 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * 255.255.255.255/32
+ *   unicast-ip4-chain
+ *   [@0]: dpo-load-balance: [index:16 buckets:1 uRPF:15 to:[0:0]]
+ *     [0] [@0]: dpo-drop ip6
+ * @cliexend
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (set_ip_flow_hash_command, static) =
+{
+  .path = "set ip flow-hash",
+  .short_help =
+  "set ip flow-hash table <table-id> [src] [dst] [sport] [dport] [proto] [reverse]",
+  .function = set_ip_flow_hash_command_fn,
+};
+/* *INDENT-ON* */
+
+int
+vnet_set_ip4_classify_intfc (vlib_main_t * vm, u32 sw_if_index,
+			     u32 table_index)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  vnet_interface_main_t *im = &vnm->interface_main;
+  ip4_main_t *ipm = &ip4_main;
+  ip_lookup_main_t *lm = &ipm->lookup_main;
+  vnet_classify_main_t *cm = &vnet_classify_main;
+  ip4_address_t *if_addr;
+
+  if (pool_is_free_index (im->sw_interfaces, sw_if_index))
+    return VNET_API_ERROR_NO_MATCHING_INTERFACE;
+
+  if (table_index != ~0 && pool_is_free_index (cm->tables, table_index))
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+
+  vec_validate (lm->classify_table_index_by_sw_if_index, sw_if_index);
+  lm->classify_table_index_by_sw_if_index[sw_if_index] = table_index;
+
+  if_addr = ip4_interface_first_address (ipm, sw_if_index, NULL);
+
+  if (NULL != if_addr)
+    {
+      fib_prefix_t pfx = {
+	.fp_len = 32,
+	.fp_proto = FIB_PROTOCOL_IP4,
+	.fp_addr.ip4 = *if_addr,
+      };
+      u32 fib_index;
+
+      fib_index = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+						       sw_if_index);
+
+
+      if (table_index != (u32) ~ 0)
+	{
+	  dpo_id_t dpo = DPO_INVALID;
+
+	  dpo_set (&dpo,
+		   DPO_CLASSIFY,
+		   DPO_PROTO_IP4,
+		   classify_dpo_create (DPO_PROTO_IP4, table_index));
+
+	  fib_table_entry_special_dpo_add (fib_index,
+					   &pfx,
+					   FIB_SOURCE_CLASSIFY,
+					   FIB_ENTRY_FLAG_NONE, &dpo);
+	  dpo_reset (&dpo);
+	}
+      else
+	{
+	  fib_table_entry_special_remove (fib_index,
+					  &pfx, FIB_SOURCE_CLASSIFY);
+	}
+    }
+
+  return 0;
+}
+
+static clib_error_t *
+set_ip_classify_command_fn (vlib_main_t * vm,
+			    unformat_input_t * input,
+			    vlib_cli_command_t * cmd)
+{
+  u32 table_index = ~0;
+  int table_index_set = 0;
+  u32 sw_if_index = ~0;
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "table-index %d", &table_index))
+	table_index_set = 1;
+      else if (unformat (input, "intfc %U", unformat_vnet_sw_interface,
+			 vnet_get_main (), &sw_if_index))
+	;
+      else
+	break;
+    }
+
+  if (table_index_set == 0)
+    return clib_error_return (0, "classify table-index must be specified");
+
+  if (sw_if_index == ~0)
+    return clib_error_return (0, "interface / subif must be specified");
+
+  rv = vnet_set_ip4_classify_intfc (vm, sw_if_index, table_index);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+
+    case VNET_API_ERROR_NO_MATCHING_INTERFACE:
+      return clib_error_return (0, "No such interface");
+
+    case VNET_API_ERROR_NO_SUCH_ENTRY:
+      return clib_error_return (0, "No such classifier table");
+    }
+  return 0;
+}
+
+/*?
+ * Assign a classification table to an interface. The classification
+ * table is created using the '<em>classify table</em>' and '<em>classify session</em>'
+ * commands. Once the table is create, use this command to filter packets
+ * on an interface.
+ *
+ * @cliexpar
+ * Example of how to assign a classification table to an interface:
+ * @cliexcmd{set ip classify intfc GigabitEthernet2/0/0 table-index 1}
+?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (set_ip_classify_command, static) =
+{
+    .path = "set ip classify",
+    .short_help =
+    "set ip classify intfc <interface> table-index <classify-idx>",
+    .function = set_ip_classify_command_fn,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */