Add support for special hostname <broadcast> (#592)

Author: jpbede

tests/test_dns.py

@@ -217,6 +217,10 @@ def test_getaddrinfo_22(self):
         self._test_getaddrinfo(payload, 80)
         self._test_getaddrinfo(payload, 80, type=socket.SOCK_STREAM)
 
+    def test_getaddrinfo_broadcast(self):
+        self._test_getaddrinfo('<broadcast>', 80)
+        self._test_getaddrinfo('<broadcast>', 80, type=socket.SOCK_STREAM)
+
     ######
 
     def test_getnameinfo_1(self):

tests/test_udp.py

@@ -378,6 +378,22 @@ def test_udp_sendto_dns(self):
         s_transport.close()
         self.loop.run_until_complete(asyncio.sleep(0.01))
 
+    def test_udp_sendto_broadcast(self):
+        coro = self.loop.create_datagram_endpoint(
+            asyncio.DatagramProtocol,
+            local_addr=('127.0.0.1', 0),
+            family=socket.AF_INET)
+
+        s_transport, server = self.loop.run_until_complete(coro)
+
+        try:
+            s_transport.sendto(b'aaaa', ('<broadcast>', 80))
+        except ValueError as exc:
+            raise AssertionError('sendto raises {}.'.format(exc))
+
+        s_transport.close()
+        self.loop.run_until_complete(asyncio.sleep(0.01))
+
     def test_send_after_close(self):
         coro = self.loop.create_datagram_endpoint(
             asyncio.DatagramProtocol,

uvloop/handles/udp.pyx

@@ -208,6 +208,10 @@ cdef class UDPTransport(UVBaseTransport):
         if addr is None:
             saddr = NULL
         else:
+            # resolve special hostname <broadcast> to the broadcast address before use
+            if self._family == uv.AF_INET and addr[0] == '<broadcast>':
+                addr = (b'255.255.255.255', addr[1])
+
             try:
                 __convert_pyaddr_to_sockaddr(self._family, addr,
                                              <system.sockaddr*>&saddr_st)