3 files changed, 21 insertions, 12 deletions

diff --git a/src/vnet/dhcp/client.c b/src/vnet/dhcp/client.c
index 1c52b0cbdbb..aac3ad3eab6 100644
--- a/src/vnet/dhcp/client.c
+++ b/src/vnet/dhcp/client.c
@@ -907,7 +907,7 @@ dhcp_client_add_del (dhcp_client_add_del_args_t * a)
 
   if (a->is_add)
     {
-      dhcp_maybe_register_udp_ports ();
+      dhcp_maybe_register_udp_ports (DHCP_PORT_REG_CLIENT);
       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 d0def3f740d..8a517080eae 100644
--- a/src/vnet/dhcp/dhcp4_proxy_node.c
+++ b/src/vnet/dhcp/dhcp4_proxy_node.c
@@ -746,21 +746,24 @@ VLIB_REGISTER_NODE (dhcp_proxy_to_client_node, static) = {
 /* *INDENT-ON* */
 
 void
-dhcp_maybe_register_udp_ports (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 (dm->udp_ports_registered)
+  if (!port_regs_diff)
     return;
 
-  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_CLIENT) & ports)
+    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 */ );
+  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 = 1;
+  dm->udp_ports_registered |= ports;
 }
 
 static clib_error_t *
@@ -799,7 +802,7 @@ 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 ();
+  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,
diff --git a/src/vnet/dhcp/dhcp_proxy.h b/src/vnet/dhcp/dhcp_proxy.h
index f8fc2902684..261dd6e1ea0 100644
--- a/src/vnet/dhcp/dhcp_proxy.h
+++ b/src/vnet/dhcp/dhcp_proxy.h
@@ -44,6 +44,12 @@ typedef enum
   DHCPV6_PROXY_N_ERROR,
 } dhcpv6_proxy_error_t;
 
+/* flags to indicate which DHCP ports should be or have been registered */
+typedef enum
+{
+  DHCP_PORT_REG_CLIENT = 0x1,
+  DHCP_PORT_REG_SERVER = 0x2,
+} dhcp_port_reg_flags_t;
 
 /**
  * @brief The Virtual Sub-net Selection information for a given RX FIB
@@ -147,7 +153,7 @@ 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 */
+  /* flags to indicate which udp ports have been registered */
   int udp_ports_registered;
 
   /* convenience */
@@ -158,9 +164,9 @@ typedef struct
 extern dhcp_proxy_main_t dhcp_proxy_main;
 
 /**
- * @brief Register the dhcp client and server ports, if not already done
+ * @brief Register the dhcp client and/or server ports, if not already done
  */
-void dhcp_maybe_register_udp_ports (void);
+void dhcp_maybe_register_udp_ports (dhcp_port_reg_flags_t ports);
 
 /**
  * @brief Send the details of a proxy session to the API client during a dump