[mbed::net] Not shutting down the socket, before closing it, is not robust in lwIP

Author: emilmont

libraries/net/lwip/Socket/Socket.cpp

@@ -69,10 +69,12 @@ int Socket::wait_writable(TimeInterval& timeout) {
     return select(&timeout._time, false, true);
 }
 
-int Socket::close() {
+int Socket::close(bool shutdown) {
     if (_sock_fd < 0)
         return -1;
 
+    if (shutdown)
+        lwip_shutdown(_sock_fd, SHUT_RDWR);
     lwip_close(_sock_fd);
     _sock_fd = -1;
 

libraries/net/lwip/Socket/Socket.h

@@ -65,9 +65,10 @@ class Socket {
         */
     int get_option(int level, int optname, void *optval, socklen_t *optlen);
 
-    /** Close the socket file descriptor
+    /** Close the socket
+        \param shutdown   free the left-over data in message queues
      */
-    int close();
+    int close(bool shutdown=true);
 
     ~Socket();
 

libraries/tests/net/echo/tcp_client_loop/main.cpp

@@ -0,0 +1,34 @@
+#include "mbed.h"
+#include "EthernetInterface.h"
+
+const char* ECHO_SERVER_ADDRESS = "10.2.200.57";
+const int ECHO_PORT = 7;
+
+int main() {
+    EthernetInterface eth;
+    eth.init(); //Use DHCP
+    eth.connect();
+    printf("IP Address is %s\n", eth.getIPAddress());
+    
+    TCPSocketConnection socket;
+    
+    while (true) {
+        while (socket.connect(ECHO_SERVER_ADDRESS, ECHO_PORT) < 0) {
+            printf("Unable to connect to (%s) on port (%d)\n", ECHO_SERVER_ADDRESS, ECHO_PORT);
+            wait(1);
+        }
+        
+        char hello[] = "Hello World\n";
+        socket.send_all(hello, sizeof(hello) - 1);
+        
+        char buf[256];
+        int n = socket.receive(buf, 256);
+        buf[n] = '\0';
+        printf("%s", buf);
+        
+        socket.close();
+        wait(1);
+    }
+    
+    eth.disconnect();
+}

workspace_tools/host_tests/tcpecho_server_loop.py

@@ -0,0 +1,24 @@
+# Be sure that the tools directory is in the search path
+import sys
+from os.path import join, abspath, dirname
+ROOT = abspath(join(dirname(__file__), "..", ".."))
+sys.path.append(ROOT)
+
+from workspace_tools.private_settings import LOCALHOST
+from SocketServer import BaseRequestHandler, TCPServer
+
+
+class TCP_EchoHandler(BaseRequestHandler):
+    def handle(self):
+        print "\nHandle connection from:", self.client_address
+        while True:
+            data = self.request.recv(1024)
+            if not data: break
+            self.request.sendall(data)
+        self.request.close()
+        print "socket closed"
+
+if __name__ == '__main__':
+    server = TCPServer((LOCALHOST, 7), TCP_EchoHandler)
+    print "listening for connections on:", (LOCALHOST, 7)
+    server.serve_forever()

workspace_tools/tests.py

@@ -500,6 +500,12 @@
         "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, ETH_LIBRARY],
         "supported": CORTEX_ARM_SUPPORT,
     },
+    {
+        "id": "NET_13", "description": "NET: TCP client echo loop",
+        "source_dir": join(TEST_DIR, "net", "echo", "tcp_client_loop"),
+        "dependencies": [MBED_LIBRARIES, RTOS_LIBRARIES, ETH_LIBRARY],
+        "supported": CORTEX_ARM_SUPPORT,
+    },
 
     # Vodafone tests
     {