extmod/modlwip: Fix close and clean up of UDP and raw sockets.

The correct callback-deregister functions must be called dependent on the
socket type, otherwise resources may not be freed correctly.

Signed-off-by: Damien George <damien@micropython.org>

extmod/modlwip.c

@@ -1502,16 +1502,16 @@ STATIC mp_uint_t lwip_socket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_
             return 0;
         }
 
-        // Deregister callback (pcb.tcp is set to NULL below so must deregister now)
-        tcp_arg(socket->pcb.tcp, NULL);
-        tcp_err(socket->pcb.tcp, NULL);
-        tcp_recv(socket->pcb.tcp, NULL);
-
         // Free any incoming buffers or connections that are stored
         lwip_socket_free_incoming(socket);
 
         switch (socket->type) {
             case MOD_NETWORK_SOCK_STREAM: {
+                // Deregister callback (pcb.tcp is set to NULL below so must deregister now)
+                tcp_arg(socket->pcb.tcp, NULL);
+                tcp_err(socket->pcb.tcp, NULL);
+                tcp_recv(socket->pcb.tcp, NULL);
+
                 if (socket->pcb.tcp->state != LISTEN) {
                     // Schedule a callback to abort the connection if it's not cleanly closed after
                     // the given timeout.  The callback must be set before calling tcp_close since
@@ -1525,10 +1525,12 @@ STATIC mp_uint_t lwip_socket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_
                 break;
             }
             case MOD_NETWORK_SOCK_DGRAM:
+                udp_recv(socket->pcb.udp, NULL, NULL);
                 udp_remove(socket->pcb.udp);
                 break;
             #if MICROPY_PY_LWIP_SOCK_RAW
             case MOD_NETWORK_SOCK_RAW:
+                raw_recv(socket->pcb.raw, NULL, NULL);
                 raw_remove(socket->pcb.raw);
                 break;
             #endif

tests/multi_net/udp_data.py

@@ -0,0 +1,35 @@
+# Simple test of a UDP server and client transferring data
+
+import socket
+
+NUM_NEW_SOCKETS = 4
+NUM_TRANSFERS = 4
+PORT = 8000
+
+# Server
+def instance0():
+    multitest.globals(IP=multitest.get_network_ip())
+    multitest.next()
+    for i in range(NUM_NEW_SOCKETS):
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.bind(socket.getaddrinfo("0.0.0.0", PORT)[0][-1])
+        multitest.broadcast("server ready")
+        for j in range(NUM_TRANSFERS):
+            data, addr = s.recvfrom(1000)
+            print(data)
+            s.sendto(b"server to client %d %d" % (i, j), addr)
+        s.close()
+
+
+# Client
+def instance1():
+    multitest.next()
+    ai = socket.getaddrinfo(IP, PORT)[0][-1]
+    for i in range(NUM_NEW_SOCKETS):
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        multitest.wait("server ready")
+        for j in range(NUM_TRANSFERS):
+            s.sendto(b"client to server %d %d" % (i, j), ai)
+            data, addr = s.recvfrom(1000)
+            print(data)
+        s.close()