dhcp: Move to plugin

Type: feature

Change-Id: I3fe27a8ef577741d9a5c4f090ec91cf68fb44fe3
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 1255 insertions, 0 deletions

diff --git a/src/plugins/dhcp/client.c b/src/plugins/dhcp/client.c
new file mode 100644
index 00000000000..800da3e504a
--- /dev/null
+++ b/src/plugins/dhcp/client.c
@@ -0,0 +1,1255 @@
+/*
+ * 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.
+ */
+#include <vlib/vlib.h>
+#include <vlibmemory/api.h>
+#include <dhcp/client.h>
+#include <dhcp/dhcp_proxy.h>
+#include <vnet/fib/fib_table.h>
+#include <vnet/qos/qos_types.h>
+
+dhcp_client_main_t dhcp_client_main;
+static u8 *format_dhcp_client_state (u8 * s, va_list * va);
+static vlib_node_registration_t dhcp_client_process_node;
+
+#define foreach_dhcp_sent_packet_stat           \
+_(DISCOVER, "DHCP discover packets sent")       \
+_(OFFER, "DHCP offer packets sent")             \
+_(REQUEST, "DHCP request packets sent")         \
+_(ACK, "DHCP ack packets sent")
+
+#define foreach_dhcp_error_counter                                      \
+_(NOT_FOR_US, "DHCP packets for other hosts, dropped")                  \
+_(NAK, "DHCP nak packets received")                                     \
+_(NON_OFFER_DISCOVER, "DHCP non-offer packets in discover state")       \
+_(ODDBALL, "DHCP non-ack, non-offer packets received")                  \
+_(BOUND, "DHCP bind success")
+
+typedef enum
+{
+#define _(sym,str) DHCP_STAT_##sym,
+  foreach_dhcp_sent_packet_stat foreach_dhcp_error_counter
+#undef _
+    DHCP_STAT_UNKNOWN,
+  DHCP_STAT_N_STAT,
+} sample_error_t;
+
+static char *dhcp_client_process_stat_strings[] = {
+#define _(sym,string) string,
+  foreach_dhcp_sent_packet_stat foreach_dhcp_error_counter
+#undef _
+    "DHCP unknown packets sent",
+};
+
+static void
+dhcp_client_acquire_address (dhcp_client_main_t * dcm, dhcp_client_t * c)
+{
+  /*
+   * Install any/all info gleaned from dhcp, right here
+   */
+  ip4_add_del_interface_address (dcm->vlib_main, c->sw_if_index,
+				 (void *) &c->leased_address,
+				 c->subnet_mask_width, 0 /*is_del */ );
+}
+
+static void
+dhcp_client_release_address (dhcp_client_main_t * dcm, dhcp_client_t * c)
+{
+  /*
+   * Remove any/all info gleaned from dhcp, right here. Caller(s)
+   * have not wiped out the info yet.
+   */
+
+  ip4_add_del_interface_address (dcm->vlib_main, c->sw_if_index,
+				 (void *) &c->leased_address,
+				 c->subnet_mask_width, 1 /*is_del */ );
+}
+
+static void
+dhcp_client_proc_callback (uword * client_index)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  ASSERT (vlib_get_thread_index () == 0);
+  vlib_process_signal_event (vm, dhcp_client_process_node.index,
+			     EVENT_DHCP_CLIENT_WAKEUP, *client_index);
+}
+
+static void
+dhcp_client_addr_callback (dhcp_client_t * c)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+
+  /* disable the feature */
+  vnet_feature_enable_disable ("ip4-unicast",
+			       "ip4-dhcp-client-detect",
+			       c->sw_if_index, 0 /* disable */ , 0, 0);
+  c->client_detect_feature_enabled = 0;
+
+  /* if renewing the lease, the address and route have already been added */
+  if (c->state == DHCP_BOUND)
+    return;
+
+  /* add the address to the interface */
+  dhcp_client_acquire_address (dcm, c);
+
+  /*
+   * Configure default IP route:
+   */
+  if (c->router_address.as_u32)
+    {
+      fib_prefix_t all_0s = {
+	.fp_len = 0,
+	.fp_addr.ip4.as_u32 = 0x0,
+	.fp_proto = FIB_PROTOCOL_IP4,
+      };
+      ip46_address_t nh = {
+	.ip4 = c->router_address,
+      };
+
+      /* *INDENT-OFF* */
+      fib_table_entry_path_add (
+	fib_table_get_index_for_sw_if_index (
+	  FIB_PROTOCOL_IP4,
+	  c->sw_if_index),
+	  &all_0s,
+	  FIB_SOURCE_DHCP,
+	  FIB_ENTRY_FLAG_NONE,
+          DPO_PROTO_IP4,
+          &nh, c->sw_if_index,
+          ~0, 1, NULL,	// no label stack
+          FIB_ROUTE_PATH_FLAG_NONE);
+      /* *INDENT-ON* */
+    }
+  if (c->dhcp_server.as_u32)
+    {
+      ip46_address_t dst = {
+	.ip4 = c->dhcp_server,
+      };
+      c->ai_ucast = adj_nbr_add_or_lock (FIB_PROTOCOL_IP4,
+					 VNET_LINK_IP4, &dst, c->sw_if_index);
+    }
+
+  /*
+   * Call the user's event callback to report DHCP information
+   */
+  if (c->event_callback)
+    c->event_callback (c->client_index, c);
+}
+
+/*
+ * dhcp_client_for_us - server-to-client callback.
+ * Called from proxy_node.c:dhcp_proxy_to_client_input().
+ * This function first decides that the packet in question is
+ * actually for the dhcp client code in case we're also acting as
+ * a dhcp proxy. Ay caramba, what a folly!
+ */
+int
+dhcp_client_for_us (u32 bi, vlib_buffer_t * b,
+		    ip4_header_t * ip,
+		    udp_header_t * udp, dhcp_header_t * dhcp)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  vlib_main_t *vm = dcm->vlib_main;
+  dhcp_client_t *c;
+  uword *p;
+  f64 now = vlib_time_now (dcm->vlib_main);
+  u8 dhcp_message_type = 0;
+  dhcp_option_t *o;
+
+  /*
+   * Doing dhcp client on this interface?
+   * Presumably we will always receive dhcp clnt for-us pkts on
+   * the interface that's asking for an address.
+   */
+  p = hash_get (dcm->client_by_sw_if_index,
+		vnet_buffer (b)->sw_if_index[VLIB_RX]);
+  if (p == 0)
+    return 0;			/* no */
+
+  c = pool_elt_at_index (dcm->clients, p[0]);
+
+  /* Mixing dhcp relay and dhcp proxy? DGMS... */
+  if (c->state == DHCP_BOUND && c->retry_count == 0)
+    return 0;
+
+  /* Packet not for us? Turf it... */
+  if (memcmp (dhcp->client_hardware_address, c->client_hardware_address,
+	      sizeof (c->client_hardware_address)))
+    {
+      vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+				   DHCP_STAT_NOT_FOR_US, 1);
+      return 0;
+    }
+
+  /* parse through the packet, learn what we can */
+  if (dhcp->your_ip_address.as_u32)
+    c->leased_address.as_u32 = dhcp->your_ip_address.as_u32;
+
+  c->dhcp_server.as_u32 = dhcp->server_ip_address.as_u32;
+
+  o = (dhcp_option_t *) dhcp->options;
+
+  while (o->option != 0xFF /* end of options */  &&
+	 (u8 *) o < (b->data + b->current_data + b->current_length))
+    {
+      switch (o->option)
+	{
+	case 53:		/* dhcp message type */
+	  dhcp_message_type = o->data[0];
+	  break;
+
+	case 51:		/* lease time */
+	  {
+	    u32 lease_time_in_seconds =
+	      clib_host_to_net_u32 (o->data_as_u32[0]);
+	    // for debug: lease_time_in_seconds = 20; /*$$$$*/
+	    c->lease_expires = now + (f64) lease_time_in_seconds;
+	    c->lease_lifetime = lease_time_in_seconds;
+	    /* Set a sensible default, in case we don't get opt 58 */
+	    c->lease_renewal_interval = lease_time_in_seconds / 2;
+	  }
+	  break;
+
+	case 58:		/* lease renew time in seconds */
+	  {
+	    u32 lease_renew_time_in_seconds =
+	      clib_host_to_net_u32 (o->data_as_u32[0]);
+	    c->lease_renewal_interval = lease_renew_time_in_seconds;
+	  }
+	  break;
+
+	case 54:		/* dhcp server address */
+	  c->dhcp_server.as_u32 = o->data_as_u32[0];
+	  break;
+
+	case 1:		/* subnet mask */
+	  {
+	    u32 subnet_mask = clib_host_to_net_u32 (o->data_as_u32[0]);
+	    c->subnet_mask_width = count_set_bits (subnet_mask);
+	  }
+	  break;
+	case 3:		/* router address */
+	  {
+	    u32 router_address = o->data_as_u32[0];
+	    c->router_address.as_u32 = router_address;
+	  }
+	  break;
+	case 6:		/* domain server address */
+	  {
+	    vec_free (c->domain_server_address);
+	    vec_validate (c->domain_server_address,
+			  o->length / sizeof (ip4_address_t) - 1);
+	    clib_memcpy (c->domain_server_address, o->data, o->length);
+	  }
+	  break;
+	case 12:		/* hostname */
+	  {
+	    /* Replace the existing hostname if necessary */
+	    vec_free (c->hostname);
+	    vec_validate (c->hostname, o->length - 1);
+	    clib_memcpy (c->hostname, o->data, o->length);
+	  }
+	  break;
+
+	  /* $$$$ Your message in this space, parse more options */
+	default:
+	  break;
+	}
+
+      o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+    }
+
+  switch (c->state)
+    {
+    case DHCP_DISCOVER:
+      if (dhcp_message_type != DHCP_PACKET_OFFER)
+	{
+	  vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+				       DHCP_STAT_NON_OFFER_DISCOVER, 1);
+	  c->next_transmit = now + 5.0;
+	  break;
+	}
+
+      /* Received an offer, go send a request */
+      c->state = DHCP_REQUEST;
+      c->retry_count = 0;
+      c->next_transmit = 0;	/* send right now... */
+      /* Poke the client process, which will send the request */
+      uword client_id = c - dcm->clients;
+      vl_api_rpc_call_main_thread (dhcp_client_proc_callback,
+				   (u8 *) & client_id, sizeof (uword));
+      break;
+
+    case DHCP_BOUND:
+    case DHCP_REQUEST:
+      if (dhcp_message_type == DHCP_PACKET_NAK)
+	{
+	  vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+				       DHCP_STAT_NAK, 1);
+	  /* Probably never happens in bound state, but anyhow... */
+	  if (c->state == DHCP_BOUND)
+	    {
+	      ip4_add_del_interface_address (dcm->vlib_main, c->sw_if_index,
+					     (void *) &c->leased_address,
+					     c->subnet_mask_width,
+					     1 /*is_del */ );
+	      vnet_feature_enable_disable ("ip4-unicast",
+					   "ip4-dhcp-client-detect",
+					   c->sw_if_index, 1 /* enable */ ,
+					   0, 0);
+	      c->client_detect_feature_enabled = 1;
+	    }
+	  /* Wipe out any memory of the address we had... */
+	  c->state = DHCP_DISCOVER;
+	  c->next_transmit = now;
+	  c->retry_count = 0;
+	  c->leased_address.as_u32 = 0;
+	  c->subnet_mask_width = 0;
+	  c->router_address.as_u32 = 0;
+	  c->lease_renewal_interval = 0;
+	  c->dhcp_server.as_u32 = 0;
+	  vec_free (c->domain_server_address);
+	  break;
+	}
+
+      if (dhcp_message_type != DHCP_PACKET_ACK &&
+	  dhcp_message_type != DHCP_PACKET_OFFER)
+	{
+	  vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+				       DHCP_STAT_NON_OFFER_DISCOVER, 1);
+	  clib_warning ("sw_if_index %d state %U message type %d",
+			c->sw_if_index, format_dhcp_client_state,
+			c->state, dhcp_message_type);
+	  c->next_transmit = now + 5.0;
+	  break;
+	}
+      /* OK, we own the address (etc), add to the routing table(s) */
+      vl_api_rpc_call_main_thread (dhcp_client_addr_callback,
+				   (u8 *) c, sizeof (*c));
+
+      c->state = DHCP_BOUND;
+      c->retry_count = 0;
+      c->next_transmit = now + (f64) c->lease_renewal_interval;
+      c->lease_expires = now + (f64) c->lease_lifetime;
+      vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+				   DHCP_STAT_BOUND, 1);
+      break;
+
+    default:
+      clib_warning ("client %d bogus state %d", c - dcm->clients, c->state);
+      break;
+    }
+
+  /* drop the pkt, return 1 */
+  vlib_buffer_free (vm, &bi, 1);
+  return 1;
+}
+
+static void
+send_dhcp_pkt (dhcp_client_main_t * dcm, dhcp_client_t * c,
+	       dhcp_packet_type_t type, int is_broadcast)
+{
+  vlib_main_t *vm = dcm->vlib_main;
+  vnet_main_t *vnm = dcm->vnet_main;
+  vnet_hw_interface_t *hw = vnet_get_sup_hw_interface (vnm, c->sw_if_index);
+  vnet_sw_interface_t *sup_sw
+    = vnet_get_sup_sw_interface (vnm, c->sw_if_index);
+  vnet_sw_interface_t *sw = vnet_get_sw_interface (vnm, c->sw_if_index);
+  vlib_buffer_t *b;
+  u32 bi;
+  ip4_header_t *ip;
+  udp_header_t *udp;
+  dhcp_header_t *dhcp;
+  u32 *to_next;
+  vlib_frame_t *f;
+  dhcp_option_t *o;
+  u16 udp_length, ip_length;
+  u32 counter_index, node_index;
+
+  /* Interface(s) down? */
+  if ((hw->flags & VNET_HW_INTERFACE_FLAG_LINK_UP) == 0)
+    return;
+  if ((sup_sw->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) == 0)
+    return;
+  if ((sw->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) == 0)
+    return;
+
+  if (vlib_buffer_alloc (vm, &bi, 1) != 1)
+    {
+      clib_warning ("buffer allocation failure");
+      c->next_transmit = 0;
+      return;
+    }
+
+  /* Build a dhcpv4 pkt from whole cloth */
+  b = vlib_get_buffer (vm, bi);
+  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
+
+  ASSERT (b->current_data == 0);
+
+  vnet_buffer (b)->sw_if_index[VLIB_RX] = c->sw_if_index;
+
+  if (is_broadcast)
+    {
+      node_index = ip4_rewrite_node.index;
+      vnet_buffer (b)->ip.adj_index[VLIB_TX] = c->ai_bcast;
+    }
+  else
+    {
+      ip_adjacency_t *adj = adj_get (c->ai_ucast);
+
+      if (IP_LOOKUP_NEXT_ARP == adj->lookup_next_index)
+	node_index = ip4_arp_node.index;
+      else
+	node_index = ip4_rewrite_node.index;
+      vnet_buffer (b)->ip.adj_index[VLIB_TX] = c->ai_ucast;
+    }
+
+  /* Enqueue the packet right now */
+  f = vlib_get_frame_to_node (vm, node_index);
+  to_next = vlib_frame_vector_args (f);
+  to_next[0] = bi;
+  f->n_vectors = 1;
+  vlib_put_frame_to_node (vm, node_index, f);
+
+  /* build the headers */
+  ip = vlib_buffer_get_current (b);
+  udp = (udp_header_t *) (ip + 1);
+  dhcp = (dhcp_header_t *) (udp + 1);
+
+  /* $$$ optimize, maybe */
+  clib_memset (ip, 0, sizeof (*ip) + sizeof (*udp) + sizeof (*dhcp));
+
+  ip->ip_version_and_header_length = 0x45;
+  ip->ttl = 128;
+  ip->protocol = IP_PROTOCOL_UDP;
+
+  ip->tos = c->dscp;
+
+  if (ip->tos)
+    {
+      /*
+       * Setup the buffer's QoS settings so any QoS marker on the egress
+       * interface, that might set VLAN CoS bits, based on this DSCP setting
+       */
+      vnet_buffer2 (b)->qos.source = QOS_SOURCE_IP;
+      vnet_buffer2 (b)->qos.bits = ip->tos;
+      b->flags |= VNET_BUFFER_F_QOS_DATA_VALID;
+    }
+
+  if (is_broadcast)
+    {
+      /* src = 0.0.0.0, dst = 255.255.255.255 */
+      ip->dst_address.as_u32 = ~0;
+    }
+  else
+    {
+      /* Renewing an active lease, plain old ip4 src/dst */
+      ip->src_address.as_u32 = c->leased_address.as_u32;
+      ip->dst_address.as_u32 = c->dhcp_server.as_u32;
+    }
+
+  udp->src_port = clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client);
+  udp->dst_port = clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_server);
+
+  /* Send the interface MAC address */
+  clib_memcpy (dhcp->client_hardware_address,
+	       vnet_sw_interface_get_hw_address (vnm, c->sw_if_index), 6);
+
+  /* And remember it for rx-packet-for-us checking */
+  clib_memcpy (c->client_hardware_address, dhcp->client_hardware_address,
+	       sizeof (c->client_hardware_address));
+
+  /* Lease renewal, set up client_ip_address */
+  if (is_broadcast == 0)
+    dhcp->client_ip_address.as_u32 = c->leased_address.as_u32;
+
+  dhcp->opcode = 1;		/* request, all we send */
+  dhcp->hardware_type = 1;	/* ethernet */
+  dhcp->hardware_address_length = 6;
+  dhcp->transaction_identifier = c->transaction_id;
+  dhcp->flags =
+    clib_host_to_net_u16 (is_broadcast && c->set_broadcast_flag ?
+			  DHCP_FLAG_BROADCAST : 0);
+  dhcp->magic_cookie.as_u32 = DHCP_MAGIC;
+
+  o = (dhcp_option_t *) dhcp->options;
+
+  /* Send option 53, the DHCP message type */
+  o->option = DHCP_PACKET_OPTION_MSG_TYPE;
+  o->length = 1;
+  o->data[0] = type;
+  o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+
+  /* Send option 57, max msg length */
+  if (0 /* not needed, apparently */ )
+    {
+      o->option = 57;
+      o->length = 2;
+      {
+	u16 *o2 = (u16 *) o->data;
+	*o2 = clib_host_to_net_u16 (1152);
+	o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+      }
+    }
+
+  /*
+   * If server ip address is available with non-zero value,
+   * option 54 (DHCP Server Identifier) is sent.
+   */
+  if (c->dhcp_server.as_u32)
+    {
+      o->option = 54;
+      o->length = 4;
+      clib_memcpy (o->data, &c->dhcp_server.as_u32, 4);
+      o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+    }
+
+  /* send option 50, requested IP address */
+  if (c->leased_address.as_u32)
+    {
+      o->option = 50;
+      o->length = 4;
+      clib_memcpy (o->data, &c->leased_address.as_u32, 4);
+      o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+    }
+
+  /* send option 12, host name */
+  if (vec_len (c->hostname))
+    {
+      o->option = 12;
+      o->length = vec_len (c->hostname);
+      clib_memcpy (o->data, c->hostname, vec_len (c->hostname));
+      o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+    }
+
+  /* send option 61, client_id */
+  if (vec_len (c->client_identifier))
+    {
+      o->option = 61;
+      o->length = vec_len (c->client_identifier);
+      clib_memcpy (o->data, c->client_identifier,
+		   vec_len (c->client_identifier));
+      o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+    }
+
+  /* $$ maybe send the client s/w version if anyone cares */
+
+  /*
+   * send option 55, parameter request list
+   * The current list - see below, matches the Linux dhcp client's list
+   * Any specific dhcp server config and/or dhcp server may or may
+   * not yield specific options.
+   */
+  o->option = 55;
+  o->length = vec_len (c->option_55_data);
+  clib_memcpy (o->data, c->option_55_data, vec_len (c->option_55_data));
+  o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+
+  /* End of list */
+  o->option = 0xff;
+  o->length = 0;
+  o++;
+
+  b->current_length = ((u8 *) o) - b->data;
+
+  /* fix ip length, checksum and udp length */
+  ip_length = vlib_buffer_length_in_chain (vm, b);
+
+  ip->length = clib_host_to_net_u16 (ip_length);
+  ip->checksum = ip4_header_checksum (ip);
+
+  udp_length = ip_length - (sizeof (*ip));
+  udp->length = clib_host_to_net_u16 (udp_length);
+
+  switch (type)
+    {
+#define _(a,b) case DHCP_PACKET_##a: {counter_index = DHCP_STAT_##a; break;}
+      foreach_dhcp_sent_packet_stat
+#undef _
+    default:
+      counter_index = DHCP_STAT_UNKNOWN;
+      break;
+    }
+
+  vlib_node_increment_counter (vm, dhcp_client_process_node.index,
+			       counter_index, 1);
+}
+
+static int
+dhcp_discover_state (dhcp_client_main_t * dcm, dhcp_client_t * c, f64 now)
+{
+  /*
+   * State machine "DISCOVER" state. Send a dhcp discover packet,
+   * eventually back off the retry rate.
+   */
+
+  if (c->client_detect_feature_enabled == 0)
+    {
+      vnet_feature_enable_disable ("ip4-unicast",
+				   "ip4-dhcp-client-detect",
+				   c->sw_if_index, 1 /* enable */ , 0, 0);
+      c->client_detect_feature_enabled = 1;
+    }
+
+  send_dhcp_pkt (dcm, c, DHCP_PACKET_DISCOVER, 1 /* is_broadcast */ );
+
+  c->retry_count++;
+  if (c->retry_count > 10)
+    c->next_transmit = now + 5.0;
+  else
+    c->next_transmit = now + 1.0;
+  return 0;
+}
+
+static int
+dhcp_request_state (dhcp_client_main_t * dcm, dhcp_client_t * c, f64 now)
+{
+  /*
+   * State machine "REQUEST" state. Send a dhcp request packet,
+   * eventually drop back to the discover state.
+   */
+  send_dhcp_pkt (dcm, c, DHCP_PACKET_REQUEST, 1 /* is_broadcast */ );
+
+  c->retry_count++;
+  if (c->retry_count > 7 /* lucky you */ )
+    {
+      c->state = DHCP_DISCOVER;
+      c->next_transmit = now;
+      c->retry_count = 0;
+      return 1;
+    }
+  c->next_transmit = now + 1.0;
+  return 0;
+}
+
+static int
+dhcp_bound_state (dhcp_client_main_t * dcm, dhcp_client_t * c, f64 now)
+{
+  /*
+   * State machine "BOUND" state. Send a dhcp request packet to renew
+   * the lease.
+   * Eventually, when the lease expires, forget the dhcp data
+   * and go back to the stone age.
+   */
+
+  /*
+   * We disable the client detect feature when we bind a
+   * DHCP address. Turn it back on again on first renew attempt.
+   * Otherwise, if the DHCP server replies we'll never see it.
+   */
+  if (c->client_detect_feature_enabled == 0)
+    {
+      vnet_feature_enable_disable ("ip4-unicast",
+				   "ip4-dhcp-client-detect",
+				   c->sw_if_index, 1 /* enable */ , 0, 0);
+      c->client_detect_feature_enabled = 1;
+    }
+
+  send_dhcp_pkt (dcm, c, DHCP_PACKET_REQUEST, 0 /* is_broadcast */ );
+
+  c->retry_count++;
+  if (c->retry_count > 10)
+    c->next_transmit = now + 5.0;
+  else
+    c->next_transmit = now + 1.0;
+
+  if (now > c->lease_expires)
+    {
+      /* Remove the default route */
+      if (c->router_address.as_u32)
+	{
+	  fib_prefix_t all_0s = {
+	    .fp_len = 0,
+	    .fp_addr.ip4.as_u32 = 0x0,
+	    .fp_proto = FIB_PROTOCOL_IP4,
+	  };
+	  ip46_address_t nh = {
+	    .ip4 = c->router_address,
+	  };
+
+	  fib_table_entry_path_remove (fib_table_get_index_for_sw_if_index
+				       (FIB_PROTOCOL_IP4, c->sw_if_index),
+				       &all_0s, FIB_SOURCE_DHCP,
+				       DPO_PROTO_IP4, &nh, c->sw_if_index, ~0,
+				       1, FIB_ROUTE_PATH_FLAG_NONE);
+	}
+      /* Remove the interface address */
+      dhcp_client_release_address (dcm, c);
+      c->state = DHCP_DISCOVER;
+      c->next_transmit = now;
+      c->retry_count = 0;
+      /* Wipe out any memory of the address we had... */
+      c->leased_address.as_u32 = 0;
+      c->subnet_mask_width = 0;
+      c->router_address.as_u32 = 0;
+      c->lease_renewal_interval = 0;
+      c->dhcp_server.as_u32 = 0;
+      return 1;
+    }
+  return 0;
+}
+
+static f64
+dhcp_client_sm (f64 now, f64 timeout, uword pool_index)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  dhcp_client_t *c;
+
+  /* deleted, pooched, yadda yadda yadda */
+  if (pool_is_free_index (dcm->clients, pool_index))
+    return timeout;
+
+  c = pool_elt_at_index (dcm->clients, pool_index);
+
+  /* Time for us to do something with this client? */
+  if (now < c->next_transmit)
+    return timeout;
+
+again:
+  switch (c->state)
+    {
+    case DHCP_DISCOVER:	/* send a discover */
+      if (dhcp_discover_state (dcm, c, now))
+	goto again;
+      break;
+
+    case DHCP_REQUEST:		/* send a request */
+      if (dhcp_request_state (dcm, c, now))
+	goto again;
+      break;
+
+    case DHCP_BOUND:		/* bound, renew needed? */
+      if (dhcp_bound_state (dcm, c, now))
+	goto again;
+      break;
+
+    default:
+      clib_warning ("dhcp client %d bogus state %d",
+		    c - dcm->clients, c->state);
+      break;
+    }
+
+  if (c->next_transmit < now + timeout)
+    return c->next_transmit - now;
+
+  return timeout;
+}
+
+static uword
+dhcp_client_process (vlib_main_t * vm,
+		     vlib_node_runtime_t * rt, vlib_frame_t * f)
+{
+  f64 timeout = 100.0;
+  f64 now;
+  uword event_type;
+  uword *event_data = 0;
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  dhcp_client_t *c;
+  int i;
+
+  while (1)
+    {
+      vlib_process_wait_for_event_or_clock (vm, timeout);
+
+      event_type = vlib_process_get_events (vm, &event_data);
+
+      now = vlib_time_now (vm);
+
+      switch (event_type)
+	{
+	case EVENT_DHCP_CLIENT_WAKEUP:
+	  for (i = 0; i < vec_len (event_data); i++)
+	    timeout = dhcp_client_sm (now, timeout, event_data[i]);
+	  break;
+
+	case ~0:
+          /* *INDENT-OFF* */
+	  pool_foreach (c, dcm->clients,
+          ({
+            timeout = dhcp_client_sm (now, timeout,
+                                      (uword) (c - dcm->clients));
+          }));
+          /* *INDENT-ON* */
+	  if (pool_elts (dcm->clients) == 0)
+	    timeout = 100.0;
+	  break;
+	}
+
+      vec_reset_length (event_data);
+    }
+
+  /* NOTREACHED */
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dhcp_client_process_node,static) = {
+    .function = dhcp_client_process,
+    .type = VLIB_NODE_TYPE_PROCESS,
+    .name = "dhcp-client-process",
+    .process_log2_n_stack_bytes = 16,
+    .n_errors = ARRAY_LEN(dhcp_client_process_stat_strings),
+    .error_strings = dhcp_client_process_stat_strings,
+};
+/* *INDENT-ON* */
+
+static u8 *
+format_dhcp_client_state (u8 * s, va_list * va)
+{
+  dhcp_client_state_t state = va_arg (*va, dhcp_client_state_t);
+  char *str = "BOGUS!";
+
+  switch (state)
+    {
+#define _(a)                                    \
+    case a:                                     \
+      str = #a;                                 \
+        break;
+      foreach_dhcp_client_state;
+#undef _
+    default:
+      break;
+    }
+
+  s = format (s, "%s", str);
+  return s;
+}
+
+static u8 *
+format_dhcp_client (u8 * s, va_list * va)
+{
+  dhcp_client_main_t *dcm = va_arg (*va, dhcp_client_main_t *);
+  dhcp_client_t *c = va_arg (*va, dhcp_client_t *);
+  int verbose = va_arg (*va, int);
+  ip4_address_t *addr;
+
+  s = format (s, "[%d] %U state %U ", c - dcm->clients,
+	      format_vnet_sw_if_index_name, dcm->vnet_main, c->sw_if_index,
+	      format_dhcp_client_state, c->state);
+
+  if (0 != c->dscp)
+    s = format (s, "dscp %d ", c->dscp);
+
+  if (c->leased_address.as_u32)
+    {
+      s = format (s, "addr %U/%d gw %U",
+		  format_ip4_address, &c->leased_address,
+		  c->subnet_mask_width, format_ip4_address,
+		  &c->router_address);
+
+      vec_foreach (addr, c->domain_server_address)
+	s = format (s, " dns %U", format_ip4_address, addr);
+    }
+  else
+    {
+      s = format (s, "no address\n");
+    }
+
+  if (verbose)
+    {
+      s =
+	format (s,
+		"\n lease: lifetime:%d renewal-interval:%d expires:%.2f (now:%.2f)",
+		c->lease_lifetime, c->lease_renewal_interval,
+		c->lease_expires, vlib_time_now (dcm->vlib_main));
+      s =
+	format (s, "\n retry-count:%d, next-xmt:%.2f", c->retry_count,
+		c->next_transmit);
+      s =
+	format (s, "\n adjacencies:[unicast:%d broadcast:%d]", c->ai_ucast,
+		c->ai_bcast);
+    }
+  return s;
+}
+
+static clib_error_t *
+show_dhcp_client_command_fn (vlib_main_t * vm,
+			     unformat_input_t * input,
+			     vlib_cli_command_t * cmd)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  dhcp_client_t *c;
+  int verbose = 0;
+  u32 sw_if_index = ~0;
+  uword *p;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "intfc %U",
+		    unformat_vnet_sw_interface, dcm->vnet_main, &sw_if_index))
+	;
+      else if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	break;
+    }
+
+  if (sw_if_index != ~0)
+    {
+      p = hash_get (dcm->client_by_sw_if_index, sw_if_index);
+      if (p == 0)
+	return clib_error_return (0, "dhcp client not configured");
+      c = pool_elt_at_index (dcm->clients, p[0]);
+      vlib_cli_output (vm, "%U", format_dhcp_client, dcm, c, verbose);
+      return 0;
+    }
+
+  /* *INDENT-OFF* */
+  pool_foreach (c, dcm->clients,
+  ({
+    vlib_cli_output (vm, "%U",
+                     format_dhcp_client, dcm,
+                     c, verbose);
+  }));
+  /* *INDENT-ON* */
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_dhcp_client_command, static) = {
+  .path = "show dhcp client",
+  .short_help = "show dhcp client [intfc <intfc>][verbose]",
+  .function = show_dhcp_client_command_fn,
+};
+/* *INDENT-ON* */
+
+
+int
+dhcp_client_add_del (dhcp_client_add_del_args_t * a)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  vlib_main_t *vm = dcm->vlib_main;
+  dhcp_client_t *c;
+  uword *p;
+  fib_prefix_t all_0s = {
+    .fp_len = 0,
+    .fp_addr.ip4.as_u32 = 0x0,
+    .fp_proto = FIB_PROTOCOL_IP4,
+  };
+
+  p = hash_get (dcm->client_by_sw_if_index, a->sw_if_index);
+
+  if ((p && a->is_add) || (!p && a->is_add == 0))
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  if (a->is_add)
+    {
+      dhcp_maybe_register_udp_ports (DHCP_PORT_REG_CLIENT);
+      pool_get (dcm->clients, c);
+      clib_memset (c, 0, sizeof (*c));
+      c->state = DHCP_DISCOVER;
+      c->sw_if_index = a->sw_if_index;
+      c->client_index = a->client_index;
+      c->pid = a->pid;
+      c->event_callback = a->event_callback;
+      c->option_55_data = a->option_55_data;
+      c->hostname = a->hostname;
+      c->client_identifier = a->client_identifier;
+      c->set_broadcast_flag = a->set_broadcast_flag;
+      c->dscp = a->dscp;
+      c->ai_ucast = ADJ_INDEX_INVALID;
+      c->ai_bcast = adj_nbr_add_or_lock (FIB_PROTOCOL_IP4,
+					 VNET_LINK_IP4,
+					 &ADJ_BCAST_ADDR, c->sw_if_index);
+
+      do
+	{
+	  c->transaction_id = random_u32 (&dcm->seed);
+	}
+      while (c->transaction_id == 0);
+
+      hash_set (dcm->client_by_sw_if_index, a->sw_if_index, c - dcm->clients);
+
+      /*
+       * In order to accept any OFFER, whether broadcasted or unicasted, we
+       * need to configure the dhcp-client-detect feature as an input feature
+       * so the DHCP OFFER is sent to the ip4-local node. Without this a
+       * broadcasted OFFER hits the 255.255.255.255/32 address and a unicast
+       * hits 0.0.0.0/0 both of which default to drop and the latter may forward
+       * of box - not what we want. Nor to we want to change these route for
+       * all interfaces in this table
+       */
+      vnet_feature_enable_disable ("ip4-unicast",
+				   "ip4-dhcp-client-detect",
+				   c->sw_if_index, 1 /* enable */ , 0, 0);
+      c->client_detect_feature_enabled = 1;
+
+      vlib_process_signal_event (vm, dhcp_client_process_node.index,
+				 EVENT_DHCP_CLIENT_WAKEUP, c - dcm->clients);
+    }
+  else
+    {
+      c = pool_elt_at_index (dcm->clients, p[0]);
+
+      if (c->router_address.as_u32)
+	{
+	  ip46_address_t nh = {
+	    .ip4 = c->router_address,
+	  };
+
+	  fib_table_entry_path_remove (fib_table_get_index_for_sw_if_index
+				       (FIB_PROTOCOL_IP4, c->sw_if_index),
+				       &all_0s, FIB_SOURCE_DHCP,
+				       DPO_PROTO_IP4, &nh, c->sw_if_index, ~0,
+				       1, FIB_ROUTE_PATH_FLAG_NONE);
+	}
+      dhcp_client_release_address (dcm, c);
+
+      adj_unlock (c->ai_ucast);
+      adj_unlock (c->ai_bcast);
+
+      vec_free (c->domain_server_address);
+      vec_free (c->option_55_data);
+      vec_free (c->hostname);
+      vec_free (c->client_identifier);
+      hash_unset (dcm->client_by_sw_if_index, c->sw_if_index);
+      pool_put (dcm->clients, c);
+    }
+  return 0;
+}
+
+int
+dhcp_client_config (u32 is_add,
+		    u32 client_index,
+		    vlib_main_t * vm,
+		    u32 sw_if_index,
+		    u8 * hostname,
+		    u8 * client_id,
+		    dhcp_event_cb_t event_callback,
+		    u8 set_broadcast_flag, ip_dscp_t dscp, u32 pid)
+{
+  dhcp_client_add_del_args_t _a, *a = &_a;
+  int rv;
+
+  clib_memset (a, 0, sizeof (*a));
+  a->is_add = is_add;
+  a->sw_if_index = sw_if_index;
+  a->client_index = client_index;
+  a->pid = pid;
+  a->event_callback = event_callback;
+  a->set_broadcast_flag = set_broadcast_flag;
+  a->dscp = dscp;
+  vec_validate (a->hostname, strlen ((char *) hostname) - 1);
+  strncpy ((char *) a->hostname, (char *) hostname, vec_len (a->hostname));
+  vec_validate (a->client_identifier, strlen ((char *) client_id) - 1);
+  strncpy ((char *) a->client_identifier, (char *) client_id,
+	   vec_len (a->client_identifier));
+
+  /*
+   * Option 55 request list. These data precisely match
+   * the Ubuntu dhcp client. YMMV.
+   */
+
+  /* Subnet Mask */
+  vec_add1 (a->option_55_data, 1);
+  /* Broadcast address */
+  vec_add1 (a->option_55_data, 28);
+  /* time offset */
+  vec_add1 (a->option_55_data, 2);
+  /* Router */
+  vec_add1 (a->option_55_data, 3);
+  /* Domain Name */
+  vec_add1 (a->option_55_data, 15);
+  /* DNS */
+  vec_add1 (a->option_55_data, 6);
+  /* Domain search */
+  vec_add1 (a->option_55_data, 119);
+  /* Host name */
+  vec_add1 (a->option_55_data, 12);
+  /* NetBIOS name server */
+  vec_add1 (a->option_55_data, 44);
+  /* NetBIOS Scope */
+  vec_add1 (a->option_55_data, 47);
+  /* MTU */
+  vec_add1 (a->option_55_data, 26);
+  /* Classless static route */
+  vec_add1 (a->option_55_data, 121);
+  /* NTP servers */
+  vec_add1 (a->option_55_data, 42);
+
+  rv = dhcp_client_add_del (a);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+
+    case VNET_API_ERROR_INVALID_VALUE:
+
+      vec_free (a->hostname);
+      vec_free (a->client_identifier);
+      vec_free (a->option_55_data);
+
+      if (is_add)
+	clib_warning ("dhcp client already enabled on intf_idx %d",
+		      sw_if_index);
+      else
+	clib_warning ("dhcp client not enabled on on intf_idx %d",
+		      sw_if_index);
+      break;
+
+    default:
+      clib_warning ("dhcp_client_add_del returned %d", rv);
+    }
+
+  return rv;
+}
+
+void
+dhcp_client_walk (dhcp_client_walk_cb_t cb, void *ctx)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  dhcp_client_t *c;
+
+  /* *INDENT-OFF* */
+  pool_foreach (c, dcm->clients,
+  ({
+    if (!cb(c, ctx))
+      break;
+  }));
+  /* *INDENT-ON* */
+
+}
+
+static clib_error_t *
+dhcp_client_set_command_fn (vlib_main_t * vm,
+			    unformat_input_t * input,
+			    vlib_cli_command_t * cmd)
+{
+
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+  u32 sw_if_index;
+  u8 *hostname = 0;
+  u8 sw_if_index_set = 0;
+  u8 set_broadcast_flag = 1;
+  int is_add = 1;
+  dhcp_client_add_del_args_t _a, *a = &_a;
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "intfc %U",
+		    unformat_vnet_sw_interface, dcm->vnet_main, &sw_if_index))
+	sw_if_index_set = 1;
+      else if (unformat (input, "hostname %v", &hostname))
+	;
+      else if (unformat (input, "del"))
+	is_add = 0;
+      else if (unformat (input, "broadcast", &set_broadcast_flag))
+	is_add = 0;
+      else
+	break;
+    }
+
+  if (sw_if_index_set == 0)
+    return clib_error_return (0, "interface not specified");
+
+  clib_memset (a, 0, sizeof (*a));
+  a->is_add = is_add;
+  a->sw_if_index = sw_if_index;
+  a->hostname = hostname;
+  a->client_identifier = format (0, "vpe 1.0%c", 0);
+  a->set_broadcast_flag = set_broadcast_flag;
+
+  /*
+   * Option 55 request list. These data precisely match
+   * the Ubuntu dhcp client. YMMV.
+   */
+
+  /* Subnet Mask */
+  vec_add1 (a->option_55_data, 1);
+  /* Broadcast address */
+  vec_add1 (a->option_55_data, 28);
+  /* time offset */
+  vec_add1 (a->option_55_data, 2);
+  /* Router */
+  vec_add1 (a->option_55_data, 3);
+  /* Domain Name */
+  vec_add1 (a->option_55_data, 15);
+  /* DNS */
+  vec_add1 (a->option_55_data, 6);
+  /* Domain search */
+  vec_add1 (a->option_55_data, 119);
+  /* Host name */
+  vec_add1 (a->option_55_data, 12);
+  /* NetBIOS name server */
+  vec_add1 (a->option_55_data, 44);
+  /* NetBIOS Scope */
+  vec_add1 (a->option_55_data, 47);
+  /* MTU */
+  vec_add1 (a->option_55_data, 26);
+  /* Classless static route */
+  vec_add1 (a->option_55_data, 121);
+  /* NTP servers */
+  vec_add1 (a->option_55_data, 42);
+
+  rv = dhcp_client_add_del (a);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+
+    case VNET_API_ERROR_INVALID_VALUE:
+
+      vec_free (a->hostname);
+      vec_free (a->client_identifier);
+      vec_free (a->option_55_data);
+      if (is_add)
+	return clib_error_return (0, "dhcp client already enabled on %U",
+				  format_vnet_sw_if_index_name,
+				  dcm->vnet_main, sw_if_index);
+      else
+	return clib_error_return (0, "dhcp client not enabled on %U",
+				  format_vnet_sw_if_index_name,
+				  dcm->vnet_main, sw_if_index);
+      break;
+
+    default:
+      vlib_cli_output (vm, "dhcp_client_add_del returned %d", rv);
+    }
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (dhcp_client_set_command, static) = {
+  .path = "set dhcp client",
+  .short_help = "set dhcp client [del] intfc <interface> [hostname <name>]",
+  .function = dhcp_client_set_command_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+dhcp_client_init (vlib_main_t * vm)
+{
+  dhcp_client_main_t *dcm = &dhcp_client_main;
+
+  dcm->vlib_main = vm;
+  dcm->vnet_main = vnet_get_main ();
+  dcm->seed = (u32) clib_cpu_time_now ();
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (dhcp_client_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */