Rewrite actual check for sockets to be cross platform

and notify when we fail to open a socket for unknown reasons.

chaos_monkey/network/tools.py

@@ -113,25 +113,30 @@ def check_tcp_ports(ip, ports, timeout=DEFAULT_TIMEOUT, get_banner=False):
             err = sock.connect_ex((ip, port))
             if err == 0:
                 good_ports.append((port, sock))
+                continue
             if err == 10035:  # WSAEWOULDBLOCK is valid, see https://msdn.microsoft.com/en-us/library/windows/desktop/ms740668%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396
                 good_ports.append((port, sock))
+                continue
+            if err == 115:  # EINPROGRESS     115     /* Operation now in progress */
+                good_ports.append((port, sock))
+                continue
+            LOG.warning("Failed to connect to port %s, error code is %d", port, err)
 
         if len(good_ports) != 0:
             time.sleep(timeout)
-            read_sockets, write_sockets, errored_sockets = \
-                select.select(
-                    [s[1] for s in good_ports],
-                    [s[1] for s in good_ports],
-                    [s[1] for s in good_ports],
-                    0)  # no timeout because we've already slept
-            connected_ports_sockets = [x for x in good_ports if x[1] in write_sockets]
+            # this is possibly connected. meaning after timeout wait, we expect to see a connection up
+            # Possible valid errors codes if we chose to check for actually closed are
+            # ECONNREFUSED (111) or WSAECONNREFUSED (10061) or WSAETIMEDOUT(10060)
+            connected_ports_sockets = [s for s in good_ports if
+                                       s[1].getsockopt(socket.SOL_SOCKET, socket.SO_ERROR) == 0]
             LOG.debug(
                 "On host %s discovered the following ports %s" %
                 (str(ip), ",".join([str(x[0]) for x in connected_ports_sockets])))
             banners = []
             if get_banner:
-                # read first X bytes
-                banners = [sock.recv(BANNER_READ) if sock in read_sockets else ""
+                readable_sockets, _, _ = select.select([s[1] for s in connected_ports_sockets], [], [], 0)
+                # read first BANNER_READ bytes
+                banners = [sock.recv(BANNER_READ) if sock in readable_sockets else ""
                            for port, sock in connected_ports_sockets]
                 pass
             # try to cleanup