Diff: features/netsocket/UDPSocket.cpp

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/features/netsocket/UDPSocket.cpp	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,154 @@
+/* Socket
+ * Copyright (c) 2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "UDPSocket.h"
+#include "Timer.h"
+#include "mbed_assert.h"
+
+UDPSocket::UDPSocket()
+    : _pending(0), _read_sem(0), _write_sem(0),
+      _read_in_progress(false), _write_in_progress(false)
+{
+}
+
+UDPSocket::~UDPSocket()
+{
+    close();
+}
+
+nsapi_protocol_t UDPSocket::get_proto()
+{
+    return NSAPI_UDP;
+}
+
+int UDPSocket::sendto(const char *host, uint16_t port, const void *data, unsigned size)
+{
+    SocketAddress address;
+    int err = _stack->gethostbyname(host, &address);
+    if (err) {
+        return NSAPI_ERROR_DNS_FAILURE;
+    }
+
+    address.set_port(port);
+
+    // sendto is thread safe
+    return sendto(address, data, size);
+}
+
+int UDPSocket::sendto(const SocketAddress &address, const void *data, unsigned size)
+{
+    _lock.lock();
+    int ret;
+
+    // If this assert is hit then there are two threads
+    // performing a send at the same time which is undefined
+    // behavior
+    MBED_ASSERT(!_write_in_progress);
+    _write_in_progress = true;
+
+    while (true) {
+        if (!_socket) {
+            ret = NSAPI_ERROR_NO_SOCKET;
+            break;
+        }
+
+        _pending = 0;
+        int sent = _stack->socket_sendto(_socket, address, data, size);
+        if ((0 == _timeout) || (NSAPI_ERROR_WOULD_BLOCK != sent)) {
+            ret = sent;
+            break;
+        } else {
+            int32_t count;
+
+            // Release lock before blocking so other threads
+            // accessing this object aren't blocked
+            _lock.unlock();
+            count = _write_sem.wait(_timeout);
+            _lock.lock();
+
+            if (count < 1) {
+                // Semaphore wait timed out so break out and return
+                ret = NSAPI_ERROR_WOULD_BLOCK;
+                break;
+            }
+        }
+    }
+
+    _write_in_progress = false;
+    _lock.unlock();
+    return ret;
+}
+
+int UDPSocket::recvfrom(SocketAddress *address, void *buffer, unsigned size)
+{
+    _lock.lock();
+    int ret;
+
+    // If this assert is hit then there are two threads
+    // performing a recv at the same time which is undefined
+    // behavior
+    MBED_ASSERT(!_read_in_progress);
+    _read_in_progress = true;
+
+    while (true) {
+        if (!_socket) {
+            ret = NSAPI_ERROR_NO_SOCKET;
+            break;
+        }
+
+        _pending = 0;
+        int recv = _stack->socket_recvfrom(_socket, address, buffer, size);
+        if ((0 == _timeout) || (NSAPI_ERROR_WOULD_BLOCK != recv)) {
+            ret = recv;
+            break;
+        } else {
+            int32_t count;
+
+            // Release lock before blocking so other threads
+            // accessing this object aren't blocked
+            _lock.unlock();
+            count = _read_sem.wait(_timeout);
+            _lock.lock();
+
+            if (count < 1) {
+                // Semaphore wait timed out so break out and return
+                ret = NSAPI_ERROR_WOULD_BLOCK;
+                break;
+            }
+        }
+    }
+
+    _read_in_progress = false;
+    _lock.unlock();
+    return ret;
+}
+
+void UDPSocket::event()
+{
+    int32_t wcount = _write_sem.wait(0);
+    if (wcount <= 1) {
+        _write_sem.release();
+    }
+    int32_t rcount = _read_sem.wait(0);
+    if (rcount <= 1) {
+        _read_sem.release();
+    }
+
+    _pending += 1;
+    if (_callback && _pending == 1) {
+        _callback();
+    }
+}