Fix network.py Intermittent Threaded Usage Failures due to Python Built-In Bug

pythonping/executor.py

@@ -241,6 +241,7 @@ def __init__(self, target, payload_provider, timeout, socket_options=(), seed_id
         self.timeout = timeout
         self.responses = ResponseList(verbose=verbose, output=output)
         self.seed_id = seed_id
+        # note that to make Communicator instances thread safe, the seed ID must be unique per thread
         if self.seed_id is None:
             self.seed_id = os.getpid() & 0xFFFF
 

pythonping/network.py

@@ -5,6 +5,8 @@
 
 class Socket:
     DONT_FRAGMENT = (socket.SOL_IP, 10, 1)           # Option value for raw socket
+    PROTO_LOOKUP = {"icmp": socket.IPPROTO_ICMP, "tcp": socket.IPPROTO_TCP, "udp": socket.IPPROTO_UDP,
+                    "ip": socket.IPPROTO_IP, "raw": socket.IPPROTO_RAW}
 
     def __init__(self, destination, protocol, source=None, options=(), buffer_size=2048):
         """Creates a network socket to exchange messages
@@ -23,14 +25,29 @@ def __init__(self, destination, protocol, source=None, options=(), buffer_size=2
             self.destination = socket.gethostbyname(destination)
         except socket.gaierror as e:
             raise RuntimeError('Cannot resolve address "' + destination + '", try verify your DNS or host file')
-        self.protocol = socket.getprotobyname(protocol)
+
+        self.protocol = Socket.getprotobyname(protocol)
         self.buffer_size = buffer_size
         if source is not None:
             raise NotImplementedError('PythonPing currently does not support specification of source IP')
         self.socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, self.protocol)
         if options:
             self.socket.setsockopt(*options)
 
+    # Implementing a version of socket.getprotobyname for this library since built-in is not thread safe
+    # for python 3.5, 3.6, and 3.7:
+    # https://bugs.python.org/issue30482
+    # This bug was causing failures as it would occasionally return a 0 (incorrect) instead of a 1 (correct)
+    # for the 'icmp' string, causing a OSError for "Protocol not supported" in multi-threaded usage:
+    # https://github.com/alessandromaggio/pythonping/issues/40
+    @staticmethod
+    def getprotobyname(name):
+        try:
+            return Socket.PROTO_LOOKUP[name.lower()]
+        except KeyError:
+            raise KeyError("'" + str(name) + "' is not in the list of supported proto types: "
+                           + str(list(Socket.PROTO_LOOKUP.keys())))
+
     def send(self, packet):
         """Sends a raw packet on the stream