utils.network: Also check for UDP protocols in is_port_free

Binding port won't complain when port already opened for UDP packets and
we are trying to bind it for TCP packets. Let's do a combination.

Note I also tried:

    tuple(getattr(socket, _) for _ in dir(socket)
          if _.startswith('SOCK_')

to cover all of the protocols, but all the time they just reported
incorrect combination so let's just stick with the most common ones.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

avocado/utils/network.py

@@ -25,31 +25,41 @@ from .data_structures import Borg
 
 #: Families taken into account in this class
 FAMILIES = (socket.AF_INET, socket.AF_INET6)
+#: Protocols taken into account in this class
+PROTOCOLS = (socket.SOCK_STREAM, socket.SOCK_DGRAM)
 
 
 def is_port_free(port, address):
     """
     Return True if the given port is available for use.
 
-    Currently we only check for TCP connections on IPv4/6
+    Currently we only check for TCP/UDP connections on IPv4/6
 
     :param port: Port number
     :param address: Socket address to bind or connect
     """
     s = None
+    if address == "localhost":
+        protocols = PROTOCOLS
+    else:
+        # sock.connect always connects for UDP
+        protocols = (socket.SOCK_STREAM, )
     try:
         for family in FAMILIES:
-            try:
-                s = socket.socket(family, socket.SOCK_STREAM)
-                if address == "localhost":
-                    s.bind((address, port))
-                else:
-                    s.connect((address, port))
-                    return False
-            except socket.error:
-                if address == "localhost":
-                    return False
-            s.close()
+            for protocol in protocols:
+                try:
+                    s = socket.socket(family, protocol)
+                    if address == "localhost":
+                        s.bind((address, port))
+                    else:
+                        s.connect((address, port))
+                        return False
+                except socket.error as exc:
+                    if exc.errno in (93, 94):   # Unsupported combinations
+                        continue
+                    if address == "localhost":
+                        return False
+                s.close()
         return True
     finally:
         if s is not None:

selftests/unit/test_utils_network.py

@@ -55,23 +55,26 @@ class FreePort(unittest.TestCase):
             else:
                 addrs = ipv6_addrs
             for addr in addrs:
-                try:
-                    sock = socket.socket(family, socket.SOCK_STREAM)
-                    sock.bind((addr, port))
-                    if network.is_port_free(port, "localhost"):
-                        bad.append("%s, %s: reports free" % (family, addr))
-                    else:
-                        good.append("%s, %s" % (family, addr))
-                except Exception as exc:
-                    if getattr(exc, 'errno', None) in (-2, 2, 22, 94):
-                        skip.append("%s, %s: Not supported: %s"
-                                    % (family, addr, exc))
-                    else:
-                        bad.append("%s, %s: Failed to bind: %s"
-                                   % (family, addr, exc))
-                finally:
-                    if sock is not None:
-                        sock.close()
+                for protocol in network.PROTOCOLS:
+                    try:
+                        sock = socket.socket(family, protocol)
+                        sock.bind((addr, port))
+                        if network.is_port_free(port, "localhost"):
+                            bad.append("%s, %s, %s: reports free"
+                                       % (family, protocol, addr))
+                        else:
+                            good.append("%s, %s, %s" % (family, protocol,
+                                                        addr))
+                    except Exception as exc:
+                        if getattr(exc, 'errno', None) in (-2, 2, 22, 94):
+                            skip.append("%s, %s, %s: Not supported: %s"
+                                        % (family, protocol, addr, exc))
+                        else:
+                            bad.append("%s, %s, %s: Failed to bind: %s"
+                                       % (family, protocol, addr, exc))
+                    finally:
+                        if sock is not None:
+                            sock.close()
         self.assertFalse(bad, "Following combinations failed:\n%s\n\n"
                          "Following combinations passed:\n%s\n\n"
                          "Following combinations were skipped:\n%s"