text: /*
   * 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>
  
  vlib_log_class_t dhcp_logger;
  
  dhcp_client_main_t dhcp_client_main;
  static vlib_node_registration_t dhcp_client_process_node;
  
  #define DHCP_DBG(...)                           \
      vlib_log_debug (dhcp_logger, __VA_ARGS__)
  
  #define DHCP_INFO(...)                          \
      vlib_log_notice (dhcp_logger, __VA_ARGS__)
  
  #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 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 installed %d", c - dcm->clients,
  	      format_vnet_sw_if_index_name, dcm->vnet_main, c->sw_if_index,
  	      format_dhcp_client_state, c->state, c->addresses_installed);
  
    if (0 != c->dscp)
      s = format (s, " dscp %d", c->dscp);
  
    if (c->installed.leased_address.as_u32)
      {
        s = format (s, " addr %U/%d gw %U server %U",
  		  format_ip4_address, &c->installed.leased_address,
  		  c->installed.subnet_mask_width,
  		  format_ip4_address, &c->installed.router_address,
  		  format_ip4_address, &c->installed.dhcp_server);
  
        vec_foreach (addr, c->domain_server_address)
  	s = format (s, " dns %U", format_ip4_address, addr);
      }
    else
      {
        s = format (s, " no address");
      }
  
    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 broadcast adjacency:%d", c->ai_bcast);
      }
    return s;
  }
  
  static void
  dhcp_client_acquire_address (dhcp_client_main_t * dcm, dhcp_client_t * c)
  {
    /*
     * Install any/all info gleaned from dhcp, right here
     */
    if (!c->addresses_installed)
      {
        ip4_add_del_interface_address (dcm->vlib_main, c->sw_if_index,
  				     (void *) &c->learned.leased_address,
  				     c->learned.subnet_mask_width,
  				     0 /*is_del */ );
        if (c->learned.router_address.as_u32)
  	{
  	  fib_prefix_t all_0s = {
  	    .fp_len = 0,
  	    .fp_proto = FIB_PROTOCOL_IP4,
  	  };
  	  ip46_address_t nh = {
  	    .ip4 = c->learned.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* */
  	}
      }
    clib_memcpy (&c->installed, &c->learned, sizeof (c->installed));
    c->addresses_installed = 1;
  }
  
  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.
     */
    if (c->addresses_installed)
      {
        ip4_add_del_interface_address (dcm->vlib_main, c->sw_if_index,
  				     (void *) &c->installed.leased_address,
  				     c->installed.subnet_mask_width,
  				     1 /*is_del */ );
  
        /* Remove the default route */
        if (c->installed.router_address.as_u32)
  	{
  	  fib_prefix_t all_0s = {
  	    .fp_len = 0,
  	    .fp_proto = FIB_PROTOCOL_IP4,
  	  };
  	  ip46_address_t nh = {
  	    .ip4 = c->installed.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);
  	}
      }
    clib_memset (&c->installed, 0, sizeof (c->installed));
    c->addresses_installed = 0;
  }
  
  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 (u32 * cindex)
  {
    dhcp_client_main_t *dcm = &dhcp_client_main;
    dhcp_client_t *c;
  
    c = pool_elt_at_index (dcm->clients, *cindex);
  
    /* 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;
  
    /* add the address to the interface if they've changed since the last time */
    if (0 != clib_memcmp (&c->installed, &c->learned, sizeof (c->learned)))
      {
        dhcp_client_release_address (dcm, c);
        dhcp_client_acquire_address (dcm, c);
      }
  
    /*
     * Call the user's event callback to report DHCP information
     */
    if (c->event_callback)
      c->event_callback (c->client_index, c);
  
    DHCP_INFO ("update: %U", format_dhcp_client, dcm, c, 1 /* verbose */ );
  }
  
  static void
  dhcp_client_reset (dhcp_client_main_t * dcm, dhcp_client_t * c)
  {
    if (c->client_detect_feature_enabled == 1)
      {
        vnet_feature_enable_disable ("ip4-unicast",
  				   "ip4-dhcp-client-detect",
  				   c->sw_if_index, 0, 0, 0);
        c->client_detect_feature_enabled = 0;
      }
  
    dhcp_client_release_address (dcm, c);
    clib_memset (&c->learned, 0, sizeof (c->installed));
    c->state = DHCP_DISCOVER;
    c->next_transmit = vlib_time_now (dcm->vlib_main);
    c->retry_count = 0;
    c->lease_renewal_interval = 0;
    vec_free (c->domain_server_address);
  }
  
  /*
   * 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 = vlib_get_main ();
    dhcp_client_t *c;
    uword *p;
    f64 now = vlib_time_now (vm);
    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->learned.leased_address.as_u32 = dhcp->your_ip_address.as_u32;
  
    c->learned.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->learned.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->learned.subnet_mask_width = count_set_bits (subnet_mask);
  	  }
  	  break;
  	case 3:		/* router address */
  	  {
  	    u32 router_address = o->data_as_u32[0];
  	    c->learned.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...
  	     Wipe out any memory of the address we had... */
  	  dhcp_client_reset (dcm, c);
  	  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) */
        {
  	/* Send the index over to the main thread, where it can retrieve
  	 * the original client */
  	u32 cindex = c - dcm->clients;
  	vl_api_force_rpc_call_main_thread (dhcp_client_addr_callback,
  					   (u8 *) & cindex, sizeof (u32));
        }
  
        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;
      }
  
    /* return 1 so the call disposes of this packet */
    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;
  
    DHCP_INFO ("send: type:%U bcast:%d %U",
  	     format_dhcp_packet_type, type,
  	     is_broadcast, format_dhcp_client, dcm, c, 1 /* verbose */ );
  
    /* 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;
    b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
  
    if (is_broadcast)
      {
        node_index = ip4_rewrite_node.index;
        vnet_buffer (b)->ip.adj_index[VLIB_TX] = c->ai_bcast;
      }
    else
      node_index = dcm->ip4_lookup_node_index;
  
    /* 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->learned.leased_address.as_u32;
        ip->dst_address.as_u32 = c->learned.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->learned.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->learned.dhcp_server.as_u32)
      {
        o->option = 54;
        o->length = 4;
        clib_memcpy (o->data, &c->learned.dhcp_server.as_u32, 4);
        o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
      }
  
    /* send option 50, requested IP address */
    if (c->learned.leased_address.as_u32)
      {
        o->option = 50;
        o->length = 4;
        clib_memcpy (o->data, &c->learned.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) + 1;
        /* Set type to zero, apparently some dhcp servers care */
        o->data[0] = 0;
        clib_memcpy (o->data + 1, 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.
     */
    /*
     * 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
     */
    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.
     */
    DHCP_INFO ("enter request: %U", format_dhcp_client, dcm, c,
  	     1 /*verbose */ );
  
    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)
  {
    /*
     * 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;
      }
  
    /*
     * 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.
     */
    if (now > c->lease_expires)
      {
        DHCP_INFO ("lease expired: %U", format_dhcp_client, dcm, c,
  		 1 /*verbose */ );
  
        /* reset all data for the client. do not send any more messages
         * since the objects to do so have been lost */
        dhcp_client_reset (dcm, c);
        return 1;
      }
  
    DHCP_INFO ("enter bound: %U", format_dhcp_client, dcm, c, 1 /* verbose */ );
    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;
  
    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 c->next_transmit;
  
    DHCP_INFO ("sm active session %d", c - dcm->clients);
  
  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;
      }
  
    return c->next_transmit;
  }
  
  static uword
  dhcp_client_process (vlib_main_t * vm,
  		     vlib_node_runtime_t * rt, vlib_frame_t * f)
  {
    f64 timeout = 1000.0;
    f64 next_expire_time, this_next_expire_time;
    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++)
  	    (void) dhcp_client_sm (now, timeout, event_data[i]);
  	  /* FALLTHROUGH */
  
  	case ~0:
  	  if (pool_elts (dcm->clients))
  	    {
                /* *INDENT-OFF* */
                next_expire_time = 1e70;
                pool_foreach (c, dcm->clients,
                ({
                  this_next_expire_time = dhcp_client_sm
                    (now, timeout, (uword) (c - dcm->clients));
                  next_expire_time = this_next_expire_time < next_expire_time ?
                    this_next_expire_time : next_expire_time;
                }));
                if (next_expire_time > now)
                  timeout = next_expire_time - now;
                else
                  {
                    clib_warning ("BUG");
                    timeout = 1.13;
                  }
                /* *INDENT-ON* */
  	    }
  	  else
  	    timeout = 1000.0;
  	  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 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;
  
    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_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);
  
        vlib_process_signal_event (vm, dhcp_client_process_node.index,
  				 EVENT_DHCP_CLIENT_WAKEUP, c - dcm->clients);
  
        DHCP_INFO ("create: %U", format_dhcp_client, dcm, c, 1 /* verbose */ );
      }
    else
      {
        c = pool_elt_at_index (dcm->clients, p[0]);
  
        dhcp_client_reset (dcm, c);
  
        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)
  	DHCP_INFO ("dhcp client already enabled on intf_idx %d", sw_if_index);
        else
  	DHCP_INFO ("not enabled on on intf_idx %d", sw_if_index);
        break;
  
      default:
        DHCP_INFO ("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, "vpp 1.1%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;
    vlib_node_t *ip4_lookup_node;
  
    ip4_lookup_node = vlib_get_node_by_name (vm, (u8 *) "ip4-lookup");
  
    /* Should never happen... */
    if (ip4_lookup_node == 0)
      return clib_error_return (0, "ip4-lookup node not found");
  
    dcm->ip4_lookup_node_index = ip4_lookup_node->index;
    dcm->vlib_main = vm;
    dcm->vnet_main = vnet_get_main ();
    dcm->seed = (u32) clib_cpu_time_now ();
  
    dhcp_logger = vlib_log_register_class ("dhcp", "client");
    DHCP_INFO ("plugin initialized");
  
    return 0;
  }
  
  VLIB_INIT_FUNCTION (dhcp_client_init);
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  