DHCP Multiple Servers (VPP-602, VPP-605)

Multiple DHCP (4 and/or 6) servers can be added and removed through multiple calls to the 'set dhcp server' API.
All 4/6/ discover/solicit messages will then be replicated to all servers in the list. The expectation is that the servers/system is configured in such a way that this is viable.
If VSS information is providied for the clinet VRF which also has multiple servers configured, then the same VSS information is sent to each server. Likewise the source address of packets sent to from VPP to each server is the same.

Change-Id: I3287cb084c84b3f612b78bc69cfcb5b9c1f8934d
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 118 insertions, 33 deletions

diff --git a/src/vnet/dhcp/dhcp4_proxy_node.c b/src/vnet/dhcp/dhcp4_proxy_node.c
index 88a99249684..1c84881a520 100644
--- a/src/vnet/dhcp/dhcp4_proxy_node.c
+++ b/src/vnet/dhcp/dhcp4_proxy_node.c
@@ -135,18 +135,17 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
           u32 original_sw_if_index = 0;
           u8  *end = NULL;
           u32 fib_index;
-          dhcp_server_t * server;
+          dhcp_proxy_t *proxy;
+          dhcp_server_t *server;
           u32 rx_sw_if_index;
           dhcp_option_t *o;
           u32 len = 0;
           vlib_buffer_free_list_t *fl;
+          u8 is_discover = 0;
 
 	  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);
 
@@ -172,16 +171,17 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
           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))
+          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;
             }
-          
+
+          server = &proxy->dhcp_servers[0];
           vlib_buffer_advance (b0, -(sizeof(*ip0)));
           ip0 = vlib_buffer_get_current (b0);
 
@@ -198,7 +198,7 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
 
           sum0 = ip0->checksum;
           old0 = ip0->src_address.as_u32;
-          new0 = server->dhcp_src_address.ip4.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 */, 
@@ -209,7 +209,7 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
           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;
+          h0->gateway_ip_address.as_u32 = proxy->dhcp_src_address.ip4.as_u32;
           pkts_to_server++;
 
           o = (dhcp_option_t *) h0->options;
@@ -220,7 +220,16 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
           end = b0->data + b0->current_data + b0->current_length;
           /* TLVs are not performance-friendly... */
           while  (o->option != 0xFF /* end of options */ && (u8 *)o < end) 
+            {
+              if (DHCP_PACKET_OPTION_MSG_TYPE == o->option)
+                {
+                  if (DHCP_PACKET_DISCOVER == o->data[0])
+                    {
+                      is_discover = 1;
+                    }
+                }
               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
@@ -340,6 +349,65 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
           
           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);
+                  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)) 
             {
@@ -350,10 +418,15 @@ dhcp_proxy_to_server_input (vlib_main_t * vm,
                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;
+                 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);
@@ -437,7 +510,8 @@ dhcp_proxy_to_client_input (vlib_main_t * vm,
       u32 error0 = (u32)~0;
       vnet_sw_interface_t *swif;
       u32 fib_index;
-      dhcp_server_t * server;
+      dhcp_proxy_t *proxy;
+      dhcp_server_t *server;
       u32 original_sw_if_index = (u32) ~0;
       ip4_address_t relay_addr = {
           .as_u32 = 0,
@@ -547,20 +621,26 @@ dhcp_proxy_to_client_input (vlib_main_t * vm,
         }
 
       fib_index = im->fib_index_by_sw_if_index [sw_if_index];
-      server = dhcp_get_server(dpm, fib_index, FIB_PROTOCOL_IP4);
+      proxy = dhcp_get_proxy(dpm, fib_index, FIB_PROTOCOL_IP4);
 
-      if (PREDICT_FALSE (NULL == server))
+      if (PREDICT_FALSE (NULL == proxy))
         {
           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;
+      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);
@@ -709,9 +789,8 @@ dhcp4_proxy_set_server (ip46_address_t *addr,
 
   if (is_del)
     {
-      rc = dhcp_proxy_server_del (FIB_PROTOCOL_IP4, rx_fib_index);
-
-      if (0 == rc)
+      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,
@@ -809,29 +888,35 @@ VLIB_CLI_COMMAND (dhcp_proxy_set_command, static) = {
 static u8 *
 format_dhcp4_proxy_server (u8 * s, va_list * args)
 {
-  dhcp_server_t * server = va_arg (*args, dhcp_server_t *);
+  dhcp_proxy_t *proxy = va_arg (*args, dhcp_proxy_t *);
   ip4_fib_t * rx_fib, * server_fib;
+  dhcp_server_t *server;
 
-  if (server == 0)
+  if (proxy == 0)
     {
-      s = format (s, "%=16s%=16s%=14s%=14s", "Server", "Src Address", 
-                  "Server FIB", "RX FIB");
+        s = format (s, "%=14s%=16s%s", "RX FIB", "Src Address", 
+                    "Servers FIB,Address");
       return s;
     }
 
-  server_fib = ip4_fib_get(server->server_fib_index);
-  rx_fib = ip4_fib_get(server->rx_fib_index);
+  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);
 
-  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);
+  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_server_t *server,
+dhcp4_proxy_show_walk (dhcp_proxy_t *server,
                        void *ctx)
 {
     vlib_main_t * vm = ctx;