Added mbedtls_net_close and use it in ssl_fork_server to correctly

disassociate the client socket from the parent process and the server
socket from the child process.

include/mbedtls/net_sockets.h

@@ -257,6 +257,13 @@ int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len );
 int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len,
                       uint32_t timeout );
 
+/**
+ * \brief          Closes down the connection and free associated data
+ *
+ * \param ctx      The context to close
+ */
+void mbedtls_net_close( mbedtls_net_context *ctx );
+
 /**
  * \brief          Gracefully shutdown the connection and free associated data
  *

library/net_sockets.c

@@ -651,6 +651,19 @@ int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len )
     return( ret );
 }
 
+/*
+ * Close the connection
+ */
+void mbedtls_net_close( mbedtls_net_context *ctx )
+{
+    if( ctx->fd == -1 )
+        return;
+
+    close( ctx->fd );
+
+    ctx->fd = -1;
+}
+
 /*
  * Gracefully close the connection
  */

programs/ssl/ssl_fork_server.c

@@ -254,6 +254,7 @@ int main( void )
         if( pid != 0 )
         {
             mbedtls_printf( " ok\n" );
+            mbedtls_net_close( &client_fd );
 
             if( ( ret = mbedtls_ctr_drbg_reseed( &ctr_drbg,
                                          (const unsigned char *) "parent",
@@ -266,7 +267,7 @@ int main( void )
             continue;
         }
 
-        mbedtls_net_init( &listen_fd );
+        mbedtls_net_close( &listen_fd );
 
         pid = getpid();