Consolidate DHCP v4 and V6 implementation. No functional change intended

The DHCP proxy and VSS information maintained by VPP is the same for v4 and v6, so we can manage this state using the same code.
Packet handling is cleary different, so this is kept separate.

Change-Id: I10f10cc1f7f19debcd4c4b099c6de64e56bb0c69
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 983 insertions, 0 deletions

diff --git a/src/vnet/dhcp/dhcp4_proxy_node.c b/src/vnet/dhcp/dhcp4_proxy_node.c
new file mode 100644
index 00000000000..88a99249684
--- /dev/null
+++ b/src/vnet/dhcp/dhcp4_proxy_node.c
@@ -0,0 +1,983 @@
+/*
+ * 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;
+          u8  *end = NULL;
+          u32 fib_index;
+          dhcp_server_t * server;
+          u32 rx_sw_if_index;
+          dhcp_option_t *o;
+          u32 len = 0;
+          vlib_buffer_free_list_t *fl;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 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];
+          server = dhcp_get_server(dpm, fib_index, FIB_PROTOCOL_IP4);
+          
+          if (PREDICT_FALSE (NULL == server))
+            {
+              error0 = DHCP_PROXY_ERROR_NO_SERVER;
+              next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
+              pkts_no_server++;
+              goto do_trace;
+            }
+          
+          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 = server->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.as_u32 = server->dhcp_src_address.ip4.as_u32;
+          pkts_to_server++;
+
+          o = (dhcp_option_t *) h0->options;
+              
+          fib_index = im->fib_index_by_sw_if_index 
+              [vnet_buffer(b0)->sw_if_index[VLIB_RX]];
+
+          end = b0->data + b0->current_data + b0->current_length;
+          /* TLVs are not performance-friendly... */
+          while  (o->option != 0xFF /* end of options */ && (u8 *)o < end) 
+              o = (dhcp_option_t *) (((uword) o) + (o->length + 2));
+
+          fl = vlib_buffer_get_free_list (vm, b0->free_list_index);
+          // start write at (option*)o, some packets have padding
+          if (((u8 *)o - (u8 *)b0->data + VPP_DHCP_OPTION82_SIZE) > fl->n_data_bytes)
+          {
+              next0 = DHCP_PROXY_TO_SERVER_INPUT_NEXT_DROP;
+              pkts_too_big++;
+              goto do_trace;
+          }
+
+          if ((o->option == 0xFF)  && ((u8 *)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;
+              sw_if_index = 0;
+              original_sw_if_index = 0;
+                  
+              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 */
+              o->data[2] = (original_sw_if_index >> 24) & 0xFF;
+              o->data[3] = (original_sw_if_index >> 16) & 0xFF;
+              o->data[4] = (original_sw_if_index >> 8)  & 0xFF;
+              o->data[5] = (original_sw_if_index >> 0)  & 0xFF;
+              o->data[6] = 5; /* suboption 5 (client RX intfc address) */
+              o->data[7] = 4; /* length 4 */
+              o->data[8] = ia0->as_u8[0];
+              o->data[9] = ia0->as_u8[1];
+              o->data[10] = ia0->as_u8[2];
+              o->data[11] = ia0->as_u8[3];
+              o->data[12] = 0xFF;
+
+              vss = dhcp_get_vss_info (dpm, fib_index, FIB_PROTOCOL_IP4);
+              if (NULL != vss)
+              {
+                  u32 opt82_fib_id=0, opt82_oui=0;
+
+                  opt82_oui =  vss->oui;
+                  opt82_fib_id =  vss->fib_id;
+
+                  o->data[12] = 151; /* vss suboption */
+                  if (255 == opt82_fib_id) {
+                      o->data[13] = 1;   /* length */
+                      o->data[14] = 255;   /* vss option type */
+                      o->data[15] = 152; /* vss control suboption */
+                      o->data[16] = 0;   /* length */
+                      /* and a new "end-of-options" option (0xff) */
+                      o->data[17] = 0xFF;
+                      o->length += 5;
+                  } else {
+                      o->data[13] = 8;   /* length */
+                      o->data[14] = 1;   /* vss option type */
+                      o->data[15] = (opt82_oui >> 16) & 0xff;
+                      o->data[16] = (opt82_oui >> 8) & 0xff;
+                      o->data[17] = (opt82_oui ) & 0xff;
+                      o->data[18] = (opt82_fib_id >> 24) & 0xff;
+                      o->data[19] = (opt82_fib_id >> 16) & 0xff;
+                      o->data[20] = (opt82_fib_id >> 8) & 0xff;
+                      o->data[21] = (opt82_fib_id) & 0xff;
+                      o->data[22] = 152; /* vss control suboption */
+                      o->data[23] = 0;   /* length */
+                          
+                      /* and a new "end-of-options" option (0xff) */
+                      o->data[24] = 0xFF;
+                      o->length += 12;
+                  }
+              }
+
+              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;
+
+        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 = server->dhcp_server.ip4.as_u32;
+            }
+
+        do_enqueue:
+	  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;
+}
+
+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
+};
+
+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 = ethernet_get_main (vm);
+  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_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 */)
+        {
+          dhcp_option_t *o = (dhcp_option_t *) h0->options;
+          dhcp_option_t *sub;
+              
+          /* 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 != 0xFF /* end of options */ &&
+                 (u8 *) o < (b0->data + b0->current_data + b0->current_length))
+            {
+              if (o->option == 82)
+                {
+                    u32 vss_exist = 0;
+                    u32 vss_ctrl = 0;
+                    sub = (dhcp_option_t *) &o->data[0];
+                    while (sub->option != 0xFF /* end of options */ &&
+                           (u8 *) sub < (u8 *)(o + o->length)) {
+                        /* 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 *) 
+                          (((uword) sub) + (sub->length + 2));
+                    }
+                    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 *) (((uword) o) + (o->length + 2));
+            }
+        }
+
+      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];
+      server = dhcp_get_server(dpm, fib_index, FIB_PROTOCOL_IP4);
+
+      if (PREDICT_FALSE (NULL == server))
+        {
+          error0 = DHCP_PROXY_ERROR_NO_SERVER;
+          goto drop_packet;
+        }
+      
+      if (ip0->src_address.as_u32 != server->dhcp_server.ip4.as_u32)
+        {             
+          error0 = DHCP_PROXY_ERROR_BAD_SVR_FIB_OR_ADDRESS;
+          goto drop_packet;
+        }
+
+      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));
+      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;
+}
+
+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
+};
+
+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;
+
+  udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_client, 
+                         dhcp_proxy_to_client_node.index, 1 /* is_ip4 */);
+
+  udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_server, 
+                         dhcp_proxy_to_server_node.index, 1 /* is_ip4 */);
+
+  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;
+
+  rx_fib_index = fib_table_find_or_create_and_lock(FIB_PROTOCOL_IP4,
+                                                   rx_table_id);
+
+  if (is_del)
+    {
+      rc = dhcp_proxy_server_del (FIB_PROTOCOL_IP4, rx_fib_index);
+
+      if (0 == rc)
+      {
+          fib_table_entry_special_remove(rx_fib_index,
+                                         &all_1s,
+                                         FIB_SOURCE_DHCP);
+          fib_table_unlock (rx_fib_index, FIB_PROTOCOL_IP4);
+      }
+    }
+  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,
+                                      ADJ_INDEX_INVALID);
+          fib_table_lock (rx_fib_index, FIB_PROTOCOL_IP4);
+      }
+  }
+  fib_table_unlock (rx_fib_index, FIB_PROTOCOL_IP4);
+
+  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;
+
+  memset(&server_addr, 0, sizeof(server_addr));
+  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);
+}
+
+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,
+};
+
+static u8 *
+format_dhcp4_proxy_server (u8 * s, va_list * args)
+{
+  dhcp_server_t * server = va_arg (*args, dhcp_server_t *);
+  ip4_fib_t * rx_fib, * server_fib;
+
+  if (server == 0)
+    {
+      s = format (s, "%=16s%=16s%=14s%=14s", "Server", "Src Address", 
+                  "Server FIB", "RX FIB");
+      return s;
+    }
+
+  server_fib = ip4_fib_get(server->server_fib_index);
+  rx_fib = ip4_fib_get(server->rx_fib_index);
+
+  s = format (s, "%=16U%=16U%=14u%=14u",
+              format_ip46_address, &server->dhcp_server, IP46_TYPE_ANY,
+              format_ip46_address, &server->dhcp_src_address, IP46_TYPE_ANY,
+              server_fib->table_id,
+              rx_fib->table_id);
+  return s;
+}
+
+static int
+dhcp4_proxy_show_walk (dhcp_server_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);
+}
+
+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,
+};
+
+static clib_error_t *
+dhcp_option_82_vss_fn (vlib_main_t * vm,
+                        unformat_input_t * input,
+                        vlib_cli_command_t * cmd)
+{
+  int is_del = 0, got_new_vpn_id=0;
+  u32 oui=0, fib_id=0, tbl_id=~0;
+
+  while (unformat_check_input(input) != UNFORMAT_END_OF_INPUT) 
+    {
+
+      if (unformat(input, "delete") || unformat(input, "del"))
+          is_del = 1;    
+      else if (unformat (input, "oui %d", &oui))
+          got_new_vpn_id = 1;
+      else if (unformat (input, "vpn-id %d", &fib_id))
+          got_new_vpn_id = 1;
+      else if (unformat (input, "table %d", &tbl_id))
+          got_new_vpn_id = 1;
+      else
+          break;
+  }
+  if (tbl_id == ~0)
+      return clib_error_return (0, "no table ID specified.");
+  
+  if (is_del || got_new_vpn_id)
+    {
+      int rv;
+      rv = dhcp_proxy_set_vss(FIB_PROTOCOL_IP4, tbl_id, oui, fib_id, is_del);
+      switch (rv)
+        {
+        case 0:
+            return 0;
+            
+        case VNET_API_ERROR_NO_SUCH_FIB:
+            return clib_error_return (0, "option 82 vss(oui:%d, vpn-id:%d) not found in table %d",
+                                      oui, fib_id, tbl_id);
+            
+        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);
+        }
+    }
+  else
+      return clib_error_return (0, "parse error`%U'",
+                                format_unformat_error, input);
+}
+
+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 <oui> vpn-id <vpn-id>",
+  .function = dhcp_option_82_vss_fn,
+};
+
+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);
+}
+
+VLIB_CLI_COMMAND (dhcp_proxy_vss_show_command, static) = {
+  .path = "show dhcp vss",
+  .short_help = "show dhcp VSS",
+  .function = dhcp_vss_show_command_fn,
+};
+
+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;
+}
+
+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,
+};