dns, dhcp: on-demand udp port registration

Change-Id: I8bf411adc6c5f4caa349d161174b544d2de3ad1d
Signed-off-by: Dave Barach <dave@barachs.net>

3 files changed, 33 insertions, 5 deletions

diff --git a/src/vnet/dhcp/client.c b/src/vnet/dhcp/client.c
index 32333054fa3..1c52b0cbdbb 100644
--- a/src/vnet/dhcp/client.c
+++ b/src/vnet/dhcp/client.c
@@ -907,6 +907,7 @@ dhcp_client_add_del (dhcp_client_add_del_args_t * a)
 
   if (a->is_add)
     {
+      dhcp_maybe_register_udp_ports ();
       pool_get (dcm->clients, c);
       clib_memset (c, 0, sizeof (*c));
       c->state = DHCP_DISCOVER;
diff --git a/src/vnet/dhcp/dhcp4_proxy_node.c b/src/vnet/dhcp/dhcp4_proxy_node.c
index 97ed3b5920a..99e5a739f74 100644
--- a/src/vnet/dhcp/dhcp4_proxy_node.c
+++ b/src/vnet/dhcp/dhcp4_proxy_node.c
@@ -736,14 +736,14 @@ VLIB_REGISTER_NODE (dhcp_proxy_to_client_node, static) = {
 };
 /* *INDENT-ON* */
 
-static clib_error_t *
-dhcp4_proxy_init (vlib_main_t * vm)
+void
+dhcp_maybe_register_udp_ports (void)
 {
   dhcp_proxy_main_t *dm = &dhcp_proxy_main;
-  vlib_node_t *error_drop_node;
+  vlib_main_t *vm = dm->vlib_main;
 
-  error_drop_node = vlib_get_node_by_name (vm, (u8 *) "error-drop");
-  dm->error_drop_node_index = error_drop_node->index;
+  if (dm->udp_ports_registered)
+    return;
 
   udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_client,
 			 dhcp_proxy_to_client_node.index, 1 /* is_ip4 */ );
@@ -751,6 +751,19 @@ dhcp4_proxy_init (vlib_main_t * vm)
   udp_register_dst_port (vm, UDP_DST_PORT_dhcp_to_server,
 			 dhcp_proxy_to_server_node.index, 1 /* is_ip4 */ );
 
+  dm->udp_ports_registered = 1;
+}
+
+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;
 }
 
@@ -777,6 +790,8 @@ dhcp4_proxy_set_server (ip46_address_t * addr,
   if (ip46_address_is_zero (src_addr))
     return VNET_API_ERROR_INVALID_SRC_ADDRESS;
 
+  dhcp_maybe_register_udp_ports ();
+
   rx_fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
 						    rx_table_id,
 						    FIB_SOURCE_DHCP);
diff --git a/src/vnet/dhcp/dhcp_proxy.h b/src/vnet/dhcp/dhcp_proxy.h
index ec43769d643..f8fc2902684 100644
--- a/src/vnet/dhcp/dhcp_proxy.h
+++ b/src/vnet/dhcp/dhcp_proxy.h
@@ -146,11 +146,23 @@ typedef struct
 
   /* hash lookup specific vrf_id -> option 82 vss suboption  */
   u32 *vss_index_by_rx_fib_index[DHCP_N_PROTOS];
+
+  /* udp ports have been registered */
+  int udp_ports_registered;
+
+  /* convenience */
+  vlib_main_t *vlib_main;
+
 } dhcp_proxy_main_t;
 
 extern dhcp_proxy_main_t dhcp_proxy_main;
 
 /**
+ * @brief Register the dhcp client and server ports, if not already done
+ */
+void dhcp_maybe_register_udp_ports (void);
+
+/**
  * @brief Send the details of a proxy session to the API client during a dump
  */
 void dhcp_send_details (fib_protocol_t proto,