text: /*
   * proxy_node.c: dhcp proxy node processing
   *
   * Copyright (c) 2013 Cisco and/or its affiliates.
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <vlib/vlib.h>
  #include <vnet/pg/pg.h>
  #include <vnet/dhcp/dhcp_proxy.h>
  #include <vnet/dhcp/client.h>
  #include <vnet/fib/ip4_fib.h>
  
  static char *dhcp_proxy_error_strings[] = {
  #define dhcp_proxy_error(n,s) s,
  #include <vnet/dhcp/dhcp4_proxy_error.def>
  #undef dhcp_proxy_error
  };
  
  #define foreach_dhcp_proxy_to_server_input_next \
    _ (DROP, "error-drop")			\
    _ (LOOKUP, "ip4-lookup")			\
    _ (SEND_TO_CLIENT, "dhcp-proxy-to-client")
  
  typedef enum
  {
  #define _(s,n) DHCP_PROXY_TO_SERVER_INPUT_NEXT_##s,
    foreach_dhcp_proxy_to_server_input_next
  #undef _
      DHCP_PROXY_TO_SERVER_INPUT_N_NEXT,
  } dhcp_proxy_to_server_input_next_t;
  
  typedef struct
  {
    /* 0 => to server, 1 => to client */
    int which;
    ip4_address_t trace_ip4_address;
    u32 error;
    u32 sw_if_index;
    u32 original_sw_if_index;
  } dhcp_proxy_trace_t;
  
  #define VPP_DHCP_OPTION82_SUB1_SIZE   6
  #define VPP_DHCP_OPTION82_SUB5_SIZE   6
  #define VPP_DHCP_OPTION82_VSS_SIZE    12
  #define VPP_DHCP_OPTION82_SIZE (VPP_DHCP_OPTION82_SUB1_SIZE + \
                                  VPP_DHCP_OPTION82_SUB5_SIZE + \
                                  VPP_DHCP_OPTION82_VSS_SIZE +3)
  
  static vlib_node_registration_t dhcp_proxy_to_server_node;
  static vlib_node_registration_t dhcp_proxy_to_client_node;
  
  static u8 *
  format_dhcp_proxy_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 *);
    dhcp_proxy_trace_t *t = va_arg (*args, dhcp_proxy_trace_t *);
  
    if (t->which == 0)
      s = format (s, "DHCP proxy: sent to server %U\n",
  		format_ip4_address, &t->trace_ip4_address, t->error);
    else
      s = format (s, "DHCP proxy: broadcast to client from %U\n",
  		format_ip4_address, &t->trace_ip4_address);
  
    if (t->error != (u32) ~ 0)
      s = format (s, "  error: %s\n", dhcp_proxy_error_strings[t->error]);
  
    s = format (s, "  original_sw_if_index: %d, sw_if_index: %d\n",
  	      t->original_sw_if_index, t->sw_if_index);
  
    return s;
  }
  
  static u8 *
  format_dhcp_proxy_header_with_length (u8 * s, va_list * args)
  {
    dhcp_header_t *h = va_arg (*args, dhcp_header_t *);
    u32 max_header_bytes = va_arg (*args, u32);
    u32 header_bytes;
  
    header_bytes = sizeof (h[0]);
    if (max_header_bytes != 0 && header_bytes > max_header_bytes)
      return format (s, "dhcp header truncated");
  
    s = format (s, "DHCP Proxy");
  
    return s;
  }
  
  static uword
  dhcp_proxy_to_server_input (vlib_main_t * vm,
  			    vlib_node_runtime_t * node,
  			    vlib_frame_t * from_frame)
  {
    u32 n_left_from, next_index, *from, *to_next;
    dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
    from = vlib_frame_vector_args (from_frame);
    n_left_from = from_frame->n_vectors;
    u32 pkts_to_server = 0, pkts_to_client = 0, pkts_no_server = 0;
    u32 pkts_no_interface_address = 0;
    u32 pkts_too_big = 0;
    ip4_main_t *im = &ip4_main;
  
    next_index = node->cached_next_index;
  
    while (n_left_from > 0)
      {
        u32 n_left_to_next;
  
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0;
  	  vlib_buffer_t *b0;
  	  udp_header_t *u0;
  	  dhcp_header_t *h0;
  	  ip4_header_t *ip0;
  	  u32 next0;
  	  u32 old0, new0;
  	  ip_csum_t sum0;
  	  u32 error0 = (u32) ~ 0;
  	  u32 sw_if_index = 0;
  	  u32 original_sw_if_index = 0;
  	  u32 fib_index;
  	  dhcp_proxy_t *proxy;
  	  dhcp_server_t *server;
  	  u32 rx_sw_if_index;
  	  dhcp_option_t *o, *end;
  	  u32 len = 0;
  	  u8 is_discover = 0;
  	  int space_left;
  
  	  bi0 = from[0];
  	  from += 1;
  	  n_left_from -= 1;
  
  	  b0 = vlib_get_buffer (vm, bi0);
  
  	  h0 = vlib_buffer_get_current (b0);
  
  	  /*
  	   * udp_local hands us the DHCP header, need udp hdr,
  	   * ip hdr to relay to server
  	   */
  	  vlib_buffer_advance (b0, -(sizeof (*u0)));
  	  u0 = vlib_buffer_get_current (b0);
  
  	  /* This blows. Return traffic has src_port = 67, dst_port = 67 */
  	  if (u0->src_port ==
  	      clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_server))
  	    {
  	      vlib_buffer_advance (b0, sizeof (*u0));
  	      next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_SEND_TO_CLIENT;
  	      error0 = 0;
  	      pkts_to_client++;
  	      goto do_enqueue;
  	    }
  
  	  rx_sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	  fib_index = im->fib_index_by_sw_if_index[rx_sw_if_index];
  	  proxy = dhcp_get_proxy (dpm, fib_index, FIB_PROTOCOL_IP4);
  
  	  if (PREDICT_FALSE (NULL == proxy))
  	    {
  	      error0 = DHCP_PROXY_ERROR_NO_SERVER;
  	      next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
  	      pkts_no_server++;
  	      goto do_trace;
  	    }
  
  	  if (!vlib_buffer_chain_linearize (vm, b0))
  	    {
  	      error0 = DHCP_PROXY_ERROR_PKT_TOO_BIG;
  	      next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
  	      pkts_too_big++;
  	      goto do_trace;
  	    }
  	  space_left = vlib_buffer_space_left_at_end (vm, b0);
  	  /* cant parse chains...
  	   * and we need some space for option 82*/
  	  if ((b0->flags & VLIB_BUFFER_NEXT_PRESENT) != 0 ||
  	      space_left < VPP_DHCP_OPTION82_SIZE)
  	    {
  	      error0 = DHCP_PROXY_ERROR_PKT_TOO_BIG;
  	      next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
  	      pkts_too_big++;
  	      goto do_trace;
  	    }
  
  	  server = &proxy->dhcp_servers[0];
  	  vlib_buffer_advance (b0, -(sizeof (*ip0)));
  	  ip0 = vlib_buffer_get_current (b0);
  
  	  /* disable UDP checksum */
  	  u0->checksum = 0;
  	  sum0 = ip0->checksum;
  	  old0 = ip0->dst_address.as_u32;
  	  new0 = server->dhcp_server.ip4.as_u32;
  	  ip0->dst_address.as_u32 = server->dhcp_server.ip4.as_u32;
  	  sum0 = ip_csum_update (sum0, old0, new0,
  				 ip4_header_t /* structure */ ,
  				 dst_address /* changed member */ );
  	  ip0->checksum = ip_csum_fold (sum0);
  
  	  sum0 = ip0->checksum;
  	  old0 = ip0->src_address.as_u32;
  	  new0 = proxy->dhcp_src_address.ip4.as_u32;
  	  ip0->src_address.as_u32 = new0;
  	  sum0 = ip_csum_update (sum0, old0, new0,
  				 ip4_header_t /* structure */ ,
  				 src_address /* changed member */ );
  	  ip0->checksum = ip_csum_fold (sum0);
  
  	  /* Send to DHCP server via the configured FIB */
  	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = server->server_fib_index;
  
  	  h0->gateway_ip_address = proxy->dhcp_src_address.ip4;
  	  pkts_to_server++;
  
  	  o = h0->options;
  	  end = (void *) vlib_buffer_get_tail (b0);
  
  	  /* TLVs are not performance-friendly... */
  	  while (o->option != DHCP_PACKET_OPTION_END && o < end)
  	    {
  	      if (DHCP_PACKET_OPTION_MSG_TYPE == o->option)
  		{
  		  if (DHCP_PACKET_DISCOVER == o->data[0])
  		    {
  		      is_discover = 1;
  		    }
  		}
  	      o = (dhcp_option_t *) (o->data + o->length);
  	    }
  
  	  if (o->option == DHCP_PACKET_OPTION_END && o <= end)
  	    {
  	      vnet_main_t *vnm = vnet_get_main ();
  	      u16 old_l0, new_l0;
  	      ip4_address_t _ia0, *ia0 = &_ia0;
  	      dhcp_vss_t *vss;
  	      vnet_sw_interface_t *swif;
  
  	      original_sw_if_index = sw_if_index =
  		vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	      swif = vnet_get_sw_interface (vnm, sw_if_index);
  	      if (swif->flags & VNET_SW_INTERFACE_FLAG_UNNUMBERED)
  		sw_if_index = swif->unnumbered_sw_if_index;
  
  	      /*
  	       * Get the first ip4 address on the [client-side]
  	       * RX interface, if not unnumbered. otherwise use
  	       * the loopback interface's ip address.
  	       */
  	      ia0 = ip4_interface_first_address (&ip4_main, sw_if_index, 0);
  
  	      if (ia0 == 0)
  		{
  		  error0 = DHCP_PROXY_ERROR_NO_INTERFACE_ADDRESS;
  		  next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
  		  pkts_no_interface_address++;
  		  goto do_trace;
  		}
  
  	      /* Add option 82 */
  	      o->option = 82;	/* option 82 */
  	      o->length = 12;	/* 12 octets to follow */
  	      o->data[0] = 1;	/* suboption 1, circuit ID (=FIB id) */
  	      o->data[1] = 4;	/* length of suboption */
  	      u32 *o_ifid = (u32 *) & o->data[2];
  	      *o_ifid = clib_host_to_net_u32 (original_sw_if_index);
  	      o->data[6] = 5;	/* suboption 5 (client RX intfc address) */
  	      o->data[7] = 4;	/* length 4 */
  	      u32 *o_addr = (u32 *) & o->data[8];
  	      *o_addr = ia0->as_u32;
  	      o->data[12] = DHCP_PACKET_OPTION_END;
  
  	      vss = dhcp_get_vss_info (dpm, fib_index, FIB_PROTOCOL_IP4);
  	      if (vss)
  		{
  		  u32 id_len;	/* length of VPN ID */
  
  		  if (vss->vss_type == VSS_TYPE_VPN_ID)
  		    {
  		      id_len = sizeof (vss->vpn_id);	/* vpn_id is 7 bytes */
  		      memcpy (&o->data[15], vss->vpn_id, id_len);
  		    }
  		  else if (vss->vss_type == VSS_TYPE_ASCII)
  		    {
  		      id_len = vec_len (vss->vpn_ascii_id);
  		      memcpy (&o->data[15], vss->vpn_ascii_id, id_len);
  		    }
  		  else		/* must be VSS_TYPE_DEFAULT, no VPN ID */
  		    id_len = 0;
  
  		  o->data[12] = 151;	/* vss suboption */
  		  o->data[13] = id_len + 1;	/* length: vss_type + id_len */
  		  o->data[14] = vss->vss_type;	/* vss option type */
  		  o->data[15 + id_len] = 152;	/* vss control suboption */
  		  o->data[16 + id_len] = 0;	/* length */
  		  o->data[17 + id_len] = DHCP_PACKET_OPTION_END;	/* "end-of-options" (0xFF) */
  		  /* 5 bytes for suboption headers 151+len, 152+len and 0xFF */
  		  o->length += id_len + 5;
  		}
  
  	      len = o->length + 3;
  	      b0->current_length += len;
  	      /* Fix IP header length and checksum */
  	      old_l0 = ip0->length;
  	      new_l0 = clib_net_to_host_u16 (old_l0);
  	      new_l0 += len;
  	      new_l0 = clib_host_to_net_u16 (new_l0);
  	      ip0->length = new_l0;
  	      sum0 = ip0->checksum;
  	      sum0 = ip_csum_update (sum0, old_l0, new_l0, ip4_header_t,
  				     length /* changed member */ );
  	      ip0->checksum = ip_csum_fold (sum0);
  
  	      /* Fix UDP length */
  	      new_l0 = clib_net_to_host_u16 (u0->length);
  	      new_l0 += len;
  	      u0->length = clib_host_to_net_u16 (new_l0);
  	    }
  	  else
  	    {
  	      vlib_node_increment_counter
  		(vm, dhcp_proxy_to_server_node.index,
  		 DHCP_PROXY_ERROR_OPTION_82_ERROR, 1);
  	    }
  
  	  next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_LOOKUP;
  
  	  /*
  	   * If we have multiple servers configured and this is the
  	   * client's discover message, then send copies to each of
  	   * those servers
  	   */
  	  if (is_discover && vec_len (proxy->dhcp_servers) > 1)
  	    {
  	      u32 ii;
  
  	      for (ii = 1; ii < vec_len (proxy->dhcp_servers); ii++)
  		{
  		  vlib_buffer_t *c0;
  		  u32 ci0;
  
  		  c0 = vlib_buffer_copy (vm, b0);
  		  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (c0);
  		  ci0 = vlib_get_buffer_index (vm, c0);
  		  server = &proxy->dhcp_servers[ii];
  
  		  ip0 = vlib_buffer_get_current (c0);
  
  		  sum0 = ip0->checksum;
  		  old0 = ip0->dst_address.as_u32;
  		  new0 = server->dhcp_server.ip4.as_u32;
  		  ip0->dst_address.as_u32 = server->dhcp_server.ip4.as_u32;
  		  sum0 = ip_csum_update (sum0, old0, new0,
  					 ip4_header_t /* structure */ ,
  					 dst_address /* changed member */ );
  		  ip0->checksum = ip_csum_fold (sum0);
  
  		  to_next[0] = ci0;
  		  to_next += 1;
  		  n_left_to_next -= 1;
  
  		  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
  						   to_next, n_left_to_next,
  						   ci0, next0);
  
  		  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
  		    {
  		      dhcp_proxy_trace_t *tr;
  
  		      tr = vlib_add_trace (vm, node, c0, sizeof (*tr));
  		      tr->which = 0;	/* to server */
  		      tr->error = error0;
  		      tr->original_sw_if_index = original_sw_if_index;
  		      tr->sw_if_index = sw_if_index;
  		      if (next0 == DHCP_PROXY_TO_SERVER_INPUT_NEXT_LOOKUP)
  			tr->trace_ip4_address.as_u32 =
  			  server->dhcp_server.ip4.as_u32;
  		    }
  
  		  if (PREDICT_FALSE (0 == n_left_to_next))
  		    {
  		      vlib_put_next_frame (vm, node, next_index,
  					   n_left_to_next);
  		      vlib_get_next_frame (vm, node, next_index,
  					   to_next, n_left_to_next);
  		    }
  		}
  	    }
  	do_trace:
  	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
  	    {
  	      dhcp_proxy_trace_t *tr = vlib_add_trace (vm, node,
  						       b0, sizeof (*tr));
  	      tr->which = 0;	/* to server */
  	      tr->error = error0;
  	      tr->original_sw_if_index = original_sw_if_index;
  	      tr->sw_if_index = sw_if_index;
  	      if (next0 == DHCP_PROXY_TO_SERVER_INPUT_NEXT_LOOKUP)
  		tr->trace_ip4_address.as_u32 =
  		  proxy->dhcp_servers[0].dhcp_server.ip4.as_u32;
  	    }
  
  	do_enqueue:
  	  to_next[0] = bi0;
  	  to_next += 1;
  	  n_left_to_next -= 1;
  
  	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
  					   to_next, n_left_to_next,
  					   bi0, next0);
  	}
  
        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
      }
    vlib_node_increment_counter (vm, dhcp_proxy_to_server_node.index,
  			       DHCP_PROXY_ERROR_RELAY_TO_CLIENT,
  			       pkts_to_client);
    vlib_node_increment_counter (vm, dhcp_proxy_to_server_node.index,
  			       DHCP_PROXY_ERROR_RELAY_TO_SERVER,
  			       pkts_to_server);
    vlib_node_increment_counter (vm, dhcp_proxy_to_server_node.index,
  			       DHCP_PROXY_ERROR_NO_SERVER, pkts_no_server);
    vlib_node_increment_counter (vm, dhcp_proxy_to_server_node.index,
  			       DHCP_PROXY_ERROR_NO_INTERFACE_ADDRESS,
  			       pkts_no_interface_address);
    vlib_node_increment_counter (vm, dhcp_proxy_to_server_node.index,
  			       DHCP_PROXY_ERROR_PKT_TOO_BIG, pkts_too_big);
    return from_frame->n_vectors;
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (dhcp_proxy_to_server_node, static) = {
    .function = dhcp_proxy_to_server_input,
    .name = "dhcp-proxy-to-server",
    /* Takes a vector of packets. */
    .vector_size = sizeof (u32),
  
    .n_errors = DHCP_PROXY_N_ERROR,
    .error_strings = dhcp_proxy_error_strings,
  
    .n_next_nodes = DHCP_PROXY_TO_SERVER_INPUT_N_NEXT,
    .next_nodes = {
  #define _(s,n) [DHCP_PROXY_TO_SERVER_INPUT_NEXT_##s] = n,
      foreach_dhcp_proxy_to_server_input_next
  #undef _
    },
  
    .format_buffer = format_dhcp_proxy_header_with_length,
    .format_trace = format_dhcp_proxy_trace,
  #if 0
    .unformat_buffer = unformat_dhcp_proxy_header,
  #endif
  };
  /* *INDENT-ON* */
  
  static uword
  dhcp_proxy_to_client_input (vlib_main_t * vm,
  			    vlib_node_runtime_t * node,
  			    vlib_frame_t * from_frame)
  {
    u32 n_left_from, *from;
    ethernet_main_t *em = vnet_get_ethernet_main ();
    dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
    vnet_main_t *vnm = vnet_get_main ();
    ip4_main_t *im = &ip4_main;
  
    from = vlib_frame_vector_args (from_frame);
    n_left_from = from_frame->n_vectors;
  
    while (n_left_from > 0)
      {
        u32 bi0;
        vlib_buffer_t *b0;
        udp_header_t *u0;
        dhcp_header_t *h0;
        ip4_header_t *ip0 = 0;
        ip4_address_t *ia0 = 0;
        u32 old0, new0;
        ip_csum_t sum0;
        ethernet_interface_t *ei0;
        ethernet_header_t *mac0;
        vnet_hw_interface_t *hi0;
        vlib_frame_t *f0;
        u32 *to_next0;
        u32 sw_if_index = ~0;
        vnet_sw_interface_t *si0;
        u32 error0 = (u32) ~ 0;
        vnet_sw_interface_t *swif;
        u32 fib_index;
        dhcp_proxy_t *proxy;
        dhcp_server_t *server;
        u32 original_sw_if_index = (u32) ~ 0;
        ip4_address_t relay_addr = {
  	.as_u32 = 0,
        };
  
        bi0 = from[0];
        from += 1;
        n_left_from -= 1;
  
        b0 = vlib_get_buffer (vm, bi0);
        h0 = vlib_buffer_get_current (b0);
  
        /*
         * udp_local hands us the DHCP header, need udp hdr,
         * ip hdr to relay to client
         */
        vlib_buffer_advance (b0, -(sizeof (*u0)));
        u0 = vlib_buffer_get_current (b0);
  
        vlib_buffer_advance (b0, -(sizeof (*ip0)));
        ip0 = vlib_buffer_get_current (b0);
  
        /* Consumed by dhcp client code? */
        if (dhcp_client_for_us (bi0, b0, ip0, u0, h0))
  	continue;
  
        if (1 /* dpm->insert_option_82 */ )
  	{
  	  /* linearize needed to "unclone" and scan options */
  	  int rv = vlib_buffer_chain_linearize (vm, b0);
  	  if ((b0->flags & VLIB_BUFFER_NEXT_PRESENT) != 0 || !rv)
  	    {
  	      error0 = DHCP_PROXY_ERROR_PKT_TOO_BIG;
  	      goto drop_packet;
  	    }
  
  	  dhcp_option_t *o = h0->options, *end =
  	    (void *) vlib_buffer_get_tail (b0);
  
  	  /* Parse through TLVs looking for option 82.
  	     The circuit-ID is the FIB number we need
  	     to track down the client-facing interface */
  
  	  while (o->option != DHCP_PACKET_OPTION_END && o < end)
  	    {
  	      if (o->option == 82)
  		{
  		  u32 vss_exist = 0;
  		  u32 vss_ctrl = 0;
  		  dhcp_option_t *sub = (dhcp_option_t *) & o->data[0];
  		  dhcp_option_t *subend =
  		    (dhcp_option_t *) (o->data + o->length);
  		  while (sub->option != DHCP_PACKET_OPTION_END
  			 && sub < subend)
  		    {
  		      /* If this is one of ours, it will have
  		         total length 12, circuit-id suboption type,
  		         and the sw_if_index */
  		      if (sub->option == 1 && sub->length == 4)
  			{
  			  sw_if_index = ((sub->data[0] << 24) |
  					 (sub->data[1] << 16) |
  					 (sub->data[2] << 8) |
  					 (sub->data[3]));
  			}
  		      else if (sub->option == 5 && sub->length == 4)
  			{
  			  relay_addr.as_u8[0] = sub->data[0];
  			  relay_addr.as_u8[1] = sub->data[1];
  			  relay_addr.as_u8[2] = sub->data[2];
  			  relay_addr.as_u8[3] = sub->data[3];
  			}
  		      else if (sub->option == 151 &&
  			       sub->length == 7 && sub->data[0] == 1)
  			vss_exist = 1;
  		      else if (sub->option == 152 && sub->length == 0)
  			vss_ctrl = 1;
  		      sub = (dhcp_option_t *) (sub->data + sub->length);
  		    }
  		  if (vss_ctrl && vss_exist)
  		    vlib_node_increment_counter
  		      (vm, dhcp_proxy_to_client_node.index,
  		       DHCP_PROXY_ERROR_OPTION_82_VSS_NOT_PROCESSED, 1);
  
  		}
  	      o = (dhcp_option_t *) (o->data + o->length);
  	    }
  	}
  
        if (sw_if_index == (u32) ~ 0)
  	{
  	  error0 = DHCP_PROXY_ERROR_NO_OPTION_82;
  
  	drop_packet:
  	  vlib_node_increment_counter (vm, dhcp_proxy_to_client_node.index,
  				       error0, 1);
  	  f0 = vlib_get_frame_to_node (vm, dpm->error_drop_node_index);
  	  to_next0 = vlib_frame_vector_args (f0);
  	  to_next0[0] = bi0;
  	  f0->n_vectors = 1;
  	  vlib_put_frame_to_node (vm, dpm->error_drop_node_index, f0);
  	  goto do_trace;
  	}
  
        if (relay_addr.as_u32 == 0)
  	{
  	  error0 = DHCP_PROXY_ERROR_BAD_OPTION_82_ADDR;
  	  goto drop_packet;
  	}
  
        if (sw_if_index >= vec_len (im->fib_index_by_sw_if_index))
  	{
  	  error0 = DHCP_PROXY_ERROR_BAD_OPTION_82_ITF;
  	  goto drop_packet;
  	}
  
        fib_index = im->fib_index_by_sw_if_index[sw_if_index];
        proxy = dhcp_get_proxy (dpm, fib_index, FIB_PROTOCOL_IP4);
  
        if (PREDICT_FALSE (NULL == proxy))
  	{
  	  error0 = DHCP_PROXY_ERROR_NO_SERVER;
  	  goto drop_packet;
  	}
  
        vec_foreach (server, proxy->dhcp_servers)
        {
  	if (ip0->src_address.as_u32 == server->dhcp_server.ip4.as_u32)
  	  {
  	    goto server_found;
  	  }
        }
  
        error0 = DHCP_PROXY_ERROR_BAD_SVR_FIB_OR_ADDRESS;
        goto drop_packet;
  
      server_found:
        vnet_buffer (b0)->sw_if_index[VLIB_TX] = sw_if_index;
  
        swif = vnet_get_sw_interface (vnm, sw_if_index);
        original_sw_if_index = sw_if_index;
        if (swif->flags & VNET_SW_INTERFACE_FLAG_UNNUMBERED)
  	sw_if_index = swif->unnumbered_sw_if_index;
  
        ia0 = ip4_interface_first_address (&ip4_main, sw_if_index, 0);
        if (ia0 == 0)
  	{
  	  error0 = DHCP_PROXY_ERROR_NO_INTERFACE_ADDRESS;
  	  goto drop_packet;
  	}
  
        if (relay_addr.as_u32 != ia0->as_u32)
  	{
  	  error0 = DHCP_PROXY_ERROR_BAD_YIADDR;
  	  goto drop_packet;
  	}
  
        u0->checksum = 0;
        u0->dst_port = clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_client);
        sum0 = ip0->checksum;
        old0 = ip0->dst_address.as_u32;
        new0 = 0xFFFFFFFF;
        ip0->dst_address.as_u32 = new0;
        sum0 = ip_csum_update (sum0, old0, new0, ip4_header_t /* structure */ ,
  			     dst_address /* offset of changed member */ );
        ip0->checksum = ip_csum_fold (sum0);
  
        sum0 = ip0->checksum;
        old0 = ip0->src_address.as_u32;
        new0 = ia0->as_u32;
        ip0->src_address.as_u32 = new0;
        sum0 = ip_csum_update (sum0, old0, new0, ip4_header_t /* structure */ ,
  			     src_address /* offset of changed member */ );
        ip0->checksum = ip_csum_fold (sum0);
  
        vlib_buffer_advance (b0, -(sizeof (ethernet_header_t)));
        si0 = vnet_get_sw_interface (vnm, original_sw_if_index);
        if (si0->type == VNET_SW_INTERFACE_TYPE_SUB)
  	vlib_buffer_advance (b0, -4 /* space for VLAN tag */ );
  
        mac0 = vlib_buffer_get_current (b0);
  
        hi0 = vnet_get_sup_hw_interface (vnm, original_sw_if_index);
        ei0 = pool_elt_at_index (em->interfaces, hi0->hw_instance);
        clib_memcpy (mac0->src_address, ei0->address, sizeof (ei0->address));
        clib_memset (mac0->dst_address, 0xff, sizeof (mac0->dst_address));
        mac0->type = (si0->type == VNET_SW_INTERFACE_TYPE_SUB) ?
  	clib_net_to_host_u16 (0x8100) : clib_net_to_host_u16 (0x0800);
  
        if (si0->type == VNET_SW_INTERFACE_TYPE_SUB)
  	{
  	  u32 *vlan_tag = (u32 *) (mac0 + 1);
  	  u32 tmp;
  	  tmp = (si0->sub.id << 16) | 0x0800;
  	  *vlan_tag = clib_host_to_net_u32 (tmp);
  	}
  
        /* $$$ This needs to be rewritten, for sure */
        f0 = vlib_get_frame_to_node (vm, hi0->output_node_index);
        to_next0 = vlib_frame_vector_args (f0);
        to_next0[0] = bi0;
        f0->n_vectors = 1;
        vlib_put_frame_to_node (vm, hi0->output_node_index, f0);
  
      do_trace:
        if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
  	{
  	  dhcp_proxy_trace_t *tr = vlib_add_trace (vm, node,
  						   b0, sizeof (*tr));
  	  tr->which = 1;	/* to client */
  	  tr->trace_ip4_address.as_u32 = ia0 ? ia0->as_u32 : 0;
  	  tr->error = error0;
  	  tr->original_sw_if_index = original_sw_if_index;
  	  tr->sw_if_index = sw_if_index;
  	}
      }
  
    return from_frame->n_vectors;
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (dhcp_proxy_to_client_node, static) = {
    .function = dhcp_proxy_to_client_input,
    .name = "dhcp-proxy-to-client",
    /* Takes a vector of packets. */
    .vector_size = sizeof (u32),
  
    .n_errors = DHCP_PROXY_N_ERROR,
    .error_strings = dhcp_proxy_error_strings,
    .format_buffer = format_dhcp_proxy_header_with_length,
    .format_trace = format_dhcp_proxy_trace,
  #if 0
    .unformat_buffer = unformat_dhcp_proxy_header,
  #endif
  };
  /* *INDENT-ON* */
  
  void
  dhcp_maybe_register_udp_ports (dhcp_port_reg_flags_t ports)
  {
    dhcp_proxy_main_t *dm = &dhcp_proxy_main;
    vlib_main_t *vm = dm->vlib_main;
    int port_regs_diff = dm->udp_ports_registered ^ ports;
  
    if (!port_regs_diff)
      return;
  
    if ((port_regs_diff & DHCP_PORT_REG_CLIENT) & ports)
      udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_client,
  			   dhcp_proxy_to_client_node.index, 1 /* is_ip4 */ );
  
    if ((port_regs_diff & DHCP_PORT_REG_SERVER) & ports)
      udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_server,
  			   dhcp_proxy_to_server_node.index, 1 /* is_ip4 */ );
  
    dm->udp_ports_registered |= ports;
  }
  
  static clib_error_t *
  dhcp4_proxy_init (vlib_main_t * vm)
  {
    dhcp_proxy_main_t *dm = &dhcp_proxy_main;
    vlib_node_t *error_drop_node;
  
    error_drop_node = vlib_get_node_by_name (vm, (u8 *) "error-drop");
    dm->error_drop_node_index = error_drop_node->index;
    dm->vlib_main = vm;
  
    return 0;
  }
  
  
  VLIB_INIT_FUNCTION (dhcp4_proxy_init);
  
  int
  dhcp4_proxy_set_server (ip46_address_t * addr,
  			ip46_address_t * src_addr,
  			u32 rx_table_id, u32 server_table_id, int is_del)
  {
    u32 rx_fib_index = 0;
    int rc = 0;
  
    const fib_prefix_t all_1s = {
      .fp_len = 32,
      .fp_addr.ip4.as_u32 = 0xffffffff,
      .fp_proto = FIB_PROTOCOL_IP4,
    };
  
    if (ip46_address_is_zero (addr))
      return VNET_API_ERROR_INVALID_DST_ADDRESS;
  
    if (ip46_address_is_zero (src_addr))
      return VNET_API_ERROR_INVALID_SRC_ADDRESS;
  
    dhcp_maybe_register_udp_ports (DHCP_PORT_REG_CLIENT | DHCP_PORT_REG_SERVER);
  
    rx_fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
  						    rx_table_id,
  						    FIB_SOURCE_DHCP);
  
    if (is_del)
      {
        if (dhcp_proxy_server_del (FIB_PROTOCOL_IP4, rx_fib_index,
  				 addr, server_table_id))
  	{
  	  fib_table_entry_special_remove (rx_fib_index,
  					  &all_1s, FIB_SOURCE_DHCP);
  	  fib_table_unlock (rx_fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_DHCP);
  	}
      }
    else
      {
        if (dhcp_proxy_server_add (FIB_PROTOCOL_IP4,
  				 addr, src_addr,
  				 rx_fib_index, server_table_id))
  	{
  	  fib_table_entry_special_add (rx_fib_index,
  				       &all_1s,
  				       FIB_SOURCE_DHCP, FIB_ENTRY_FLAG_LOCAL);
  	  fib_table_lock (rx_fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_DHCP);
  	}
      }
    fib_table_unlock (rx_fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_DHCP);
  
    return (rc);
  }
  
  static clib_error_t *
  dhcp4_proxy_set_command_fn (vlib_main_t * vm,
  			    unformat_input_t * input,
  			    vlib_cli_command_t * cmd)
  {
    ip46_address_t server_addr, src_addr;
    u32 server_table_id = 0, rx_table_id = 0;
    int is_del = 0;
    int set_src = 0, set_server = 0;
  
    clib_memset (&server_addr, 0, sizeof (server_addr));
    clib_memset (&src_addr, 0, sizeof (src_addr));
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
        if (unformat (input, "server %U",
  		    unformat_ip4_address, &server_addr.ip4))
  	set_server = 1;
        else if (unformat (input, "server-fib-id %d", &server_table_id))
  	;
        else if (unformat (input, "rx-fib-id %d", &rx_table_id))
  	;
        else if (unformat (input, "src-address %U",
  			 unformat_ip4_address, &src_addr.ip4))
  	set_src = 1;
        else if (unformat (input, "delete") || unformat (input, "del"))
  	is_del = 1;
        else
  	break;
      }
  
    if (is_del || (set_server && set_src))
      {
        int rv;
  
        rv = dhcp4_proxy_set_server (&server_addr, &src_addr, rx_table_id,
  				   server_table_id, is_del);
        switch (rv)
  	{
  	case 0:
  	  return 0;
  
  	case VNET_API_ERROR_INVALID_DST_ADDRESS:
  	  return clib_error_return (0, "Invalid server address");
  
  	case VNET_API_ERROR_INVALID_SRC_ADDRESS:
  	  return clib_error_return (0, "Invalid src address");
  
  	case VNET_API_ERROR_NO_SUCH_ENTRY:
  	  return clib_error_return
  	    (0, "Fib id %d: no per-fib DHCP server configured", rx_table_id);
  
  	default:
  	  return clib_error_return (0, "BUG: rv %d", rv);
  	}
      }
    else
      return clib_error_return (0, "parse error`%U'",
  			      format_unformat_error, input);
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (dhcp_proxy_set_command, static) = {
    .path = "set dhcp proxy",
    .short_help = "set dhcp proxy [del] server <ip-addr> src-address <ip-addr> [server-fib-id <n>] [rx-fib-id <n>]",
    .function = dhcp4_proxy_set_command_fn,
  };
  /* *INDENT-ON* */
  
  static u8 *
  format_dhcp4_proxy_server (u8 * s, va_list * args)
  {
    dhcp_proxy_t *proxy = va_arg (*args, dhcp_proxy_t *);
    ip4_fib_t *rx_fib, *server_fib;
    dhcp_server_t *server;
  
    if (proxy == 0)
      {
        s = format (s, "%=14s%=16s%s", "RX FIB", "Src Address",
  		  "Servers FIB,Address");
        return s;
      }
  
    rx_fib = ip4_fib_get (proxy->rx_fib_index);
  
    s = format (s, "%=14u%=16U",
  	      rx_fib->table_id,
  	      format_ip46_address, &proxy->dhcp_src_address, IP46_TYPE_ANY);
  
    vec_foreach (server, proxy->dhcp_servers)
    {
      server_fib = ip4_fib_get (server->server_fib_index);
      s = format (s, "%u,%U  ",
  		server_fib->table_id,
  		format_ip46_address, &server->dhcp_server, IP46_TYPE_ANY);
    }
    return s;
  }
  
  static int
  dhcp4_proxy_show_walk (dhcp_proxy_t * server, void *ctx)
  {
    vlib_main_t *vm = ctx;
  
    vlib_cli_output (vm, "%U", format_dhcp4_proxy_server, server);
  
    return (1);
  }
  
  static clib_error_t *
  dhcp4_proxy_show_command_fn (vlib_main_t * vm,
  			     unformat_input_t * input,
  			     vlib_cli_command_t * cmd)
  {
    vlib_cli_output (vm, "%U", format_dhcp4_proxy_server,
  		   NULL /* header line */ );
  
    dhcp_proxy_walk (FIB_PROTOCOL_IP4, dhcp4_proxy_show_walk, vm);
  
    return (NULL);
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (dhcp_proxy_show_command, static) = {
    .path = "show dhcp proxy",
    .short_help = "Display dhcp proxy server info",
    .function = dhcp4_proxy_show_command_fn,
  };
  /* *INDENT-ON* */
  
  static clib_error_t *
  dhcp_option_82_vss_fn (vlib_main_t * vm,
  		       unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    u8 is_del = 0, vss_type = VSS_TYPE_DEFAULT;
    u32 oui = 0, fib_id = 0, tbl_id = ~0;
    u8 *vpn_ascii_id = 0;
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
        if (unformat (input, "table %d", &tbl_id))
  	;
        else if (unformat (input, "oui %d", &oui))
  	vss_type = VSS_TYPE_VPN_ID;
        else if (unformat (input, "vpn-id %d", &fib_id))
  	vss_type = VSS_TYPE_VPN_ID;
        else if (unformat (input, "vpn-ascii-id %s", &vpn_ascii_id))
  	vss_type = VSS_TYPE_ASCII;
        else if (unformat (input, "delete") || unformat (input, "del"))
  	is_del = 1;
        else
  	break;
      }
  
    if (tbl_id == ~0)
      return clib_error_return (0, "no table ID specified.");
  
    int rv = dhcp_proxy_set_vss (FIB_PROTOCOL_IP4, tbl_id, vss_type,
  			       vpn_ascii_id, oui, fib_id, is_del);
    switch (rv)
      {
      case 0:
        return 0;
      case VNET_API_ERROR_NO_SUCH_ENTRY:
        return clib_error_return (0,
  				"option 82 vss for table %d not found in in pool.",
  				tbl_id);
      default:
        return clib_error_return (0, "BUG: rv %d", rv);
  
      }
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (dhcp_proxy_vss_command,static) = {
    .path = "set dhcp option-82 vss",
    .short_help = "set dhcp option-82 vss [del] table <table id> [oui <n> vpn-id <n> | vpn-ascii-id <text>]",
    .function = dhcp_option_82_vss_fn,
  };
  /* *INDENT-ON* */
  
  static clib_error_t *
  dhcp_vss_show_command_fn (vlib_main_t * vm,
  			  unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    dhcp_vss_walk (FIB_PROTOCOL_IP4, dhcp_vss_show_walk, vm);
  
    return (NULL);
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (dhcp_proxy_vss_show_command, static) = {
    .path = "show dhcp vss",
    .short_help = "show dhcp VSS",
    .function = dhcp_vss_show_command_fn,
  };
  /* *INDENT-ON* */
  
  static clib_error_t *
  dhcp_option_82_address_show_command_fn (vlib_main_t * vm,
  					unformat_input_t * input,
  					vlib_cli_command_t * cmd)
  {
    vnet_main_t *vnm = vnet_get_main ();
    u32 sw_if_index0 = 0, sw_if_index;
    vnet_sw_interface_t *swif;
    ip4_address_t *ia0;
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
  
        if (unformat (input, "%U",
  		    unformat_vnet_sw_interface, vnm, &sw_if_index0))
  	{
  	  swif = vnet_get_sw_interface (vnm, sw_if_index0);
  	  sw_if_index = (swif->flags & VNET_SW_INTERFACE_FLAG_UNNUMBERED) ?
  	    swif->unnumbered_sw_if_index : sw_if_index0;
  	  ia0 = ip4_interface_first_address (&ip4_main, sw_if_index, 0);
  	  if (ia0)
  	    {
  	      vlib_cli_output (vm, "%=20s%=20s", "interface",
  			       "source IP address");
  
  	      vlib_cli_output (vm, "%=20U%=20U",
  			       format_vnet_sw_if_index_name,
  			       vnm, sw_if_index0, format_ip4_address, ia0);
  	    }
  	  else
  	    vlib_cli_output (vm, "%=34s %=20U",
  			     "No IPv4 address configured on",
  			     format_vnet_sw_if_index_name, vnm, sw_if_index);
  	}
        else
  	break;
      }
  
    return 0;
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (dhcp_proxy_address_show_command,static) = {
    .path = "show dhcp option-82-address interface",
    .short_help = "show dhcp option-82-address interface <interface>",
    .function = dhcp_option_82_address_show_command_fn,
  };
  /* *INDENT-ON* */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  