Merge pull request #2440 from geky/nsapi-lwip-reuseaddr

[nsapi] Add support for NSAPI_REUSEADDR to the lwip interface

Author: 0xc0170

features/net/FEATURE_IPV4/lwip-interface/lwip_stack.c

@@ -28,6 +28,7 @@
 #include "lwip/dhcp.h"
 #include "lwip/tcpip.h"
 #include "lwip/tcp.h"
+#include "lwip/ip.h"
 
 
 /* Static arena of sockets */
@@ -415,6 +416,18 @@ static int lwip_setsockopt(nsapi_stack_t *stack, nsapi_socket_t handle, int leve
             s->conn->pcb.tcp->keep_intvl = *(int*)optval;
             return 0;
 
+        case NSAPI_REUSEADDR:
+            if (optlen != sizeof(int)) {
+                return NSAPI_ERROR_UNSUPPORTED;
+            }
+
+            if (*(int *)optval) {
+                s->conn->pcb.tcp->so_options |= SOF_REUSEADDR;
+            } else {
+                s->conn->pcb.tcp->so_options &= ~SOF_REUSEADDR;
+            }
+            return 0;
+
         default:
             return NSAPI_ERROR_UNSUPPORTED;
     }

features/net/FEATURE_IPV4/lwip-interface/lwipopts.h

@@ -67,6 +67,8 @@
 #define LWIP_DHCP                   1
 #define LWIP_DNS                    1
 
+#define SO_REUSE                    1
+
 // Support Multicast
 #include "stdlib.h"
 #define LWIP_IGMP                   1