Only accept numeric address in getnameinfo (#2003)

* Only accept numeric address in getnameinfo

* Simplify getnameinfo implementation

* Add some test cases

* Don't check host name

Author: slozier

src/core/IronPython.Modules/_socket.cs

@@ -1151,7 +1151,8 @@ public static object getnameinfo(CodeContext/*!*/ context, [NotNone] PythonTuple
 
             string host = Converter.ConvertToString(socketAddr[0]);
             if (host == null) throw PythonOps.TypeError("argument 1 must be string");
-            int port = 0;
+
+            int port;
             try {
                 port = (int)socketAddr[1]!;
             } catch (InvalidCastException) {
@@ -1167,60 +1168,45 @@ public static object getnameinfo(CodeContext/*!*/ context, [NotNone] PythonTuple
                 }
             }
 
-            string resultHost;
-            string resultPort;
-
             // Host
-            IList<IPAddress> addrs;
-            try {
-                addrs = HostToAddresses(context, host, AddressFamily.InterNetwork);
-            } catch (IndexOutOfRangeException) {
+            if (!IPAddress.TryParse(host, out IPAddress? addr)) {
                 throw MakeGaiException(context, EAI_NODATA);
             }
 
-            if (addrs.Count > 1) {
-                // ignore non-IPV4 addresses
-                List<IPAddress> newAddrs = new List<IPAddress>(addrs.Count);
-                foreach (IPAddress addr in addrs) {
-                    if (addr.AddressFamily == AddressFamily.InterNetwork) {
-                        newAddrs.Add(addr);
+            string resultHost;
+            if ((flags & NI_NUMERICHOST) != 0) {
+                resultHost = addr.ToString();
+            } else {
+                string hostName;
+                if (addr.Equals(IPAddress.Any) || addr.Equals(IPAddress.IPv6Any)) {
+                    hostName = Dns.GetHostName();
+                } else {
+                    try {
+                        hostName = Dns.GetHostEntry(addr).HostName;
+                    } catch (SocketException ex) {
+                        throw MakeGaiException(context, ex);
                     }
                 }
-                if (newAddrs.Count > 1) {
-                    throw PythonExceptions.CreateThrowable(error, "sockaddr resolved to multiple addresses");
-                }
-                addrs = newAddrs;
-            }
 
-            if (addrs.Count < 1) {
-                throw MakeGaiException(context, EAI_NODATA);
-            }
-
-            IPHostEntry hostEntry;
-            try {
-                hostEntry = Dns.GetHostEntry(addrs[0]);
-            } catch (SocketException ex) {
-                throw MakeGaiException(context, ex);
-            }
-            if ((flags & (int)NI_NUMERICHOST) != 0) {
-                resultHost = addrs[0].ToString();
-            } else if ((flags & (int)NI_NOFQDN) != 0) {
-                resultHost = RemoveLocalDomain(hostEntry.HostName);
-            } else {
-                resultHost = hostEntry.HostName;
+                if ((flags & NI_NOFQDN) != 0) {
+                    resultHost = RemoveLocalDomain(hostName);
+                } else {
+                    resultHost = hostName;
+                }
             }
 
             // Port
-            if ((flags & (int)NI_NUMERICSERV) == 0) {
+            string resultPort;
+            if ((flags & NI_NUMERICSERV) == 0) {
                 //call the servbyport to translate port if not just use the port.ToString as the result
                 try {
                     resultPort = getservbyport(context, port);
                 } catch {
                     resultPort = port.ToString();
                 }
-                flags = flags | (int)NI_NUMERICSERV;
-            } else
+            } else {
                 resultPort = port.ToString();
+            }
 
             return PythonTuple.MakeTuple(resultHost, resultPort);
         }
@@ -2032,7 +2018,7 @@ private static IPAddress[] HostToAddresses(CodeContext/*!*/ context, string host
                     if (addrs.Count > 0) return addrs.ToArray();
                 }
                 throw MakeGaiException(context, EAI_NODATA);
-            } catch  (SocketException ex) {
+            } catch (SocketException ex) {
                 throw MakeGaiException(context, ex);
             }
         }

src/core/IronPython/Runtime/Operations/StringOps.cs

@@ -623,6 +623,7 @@ public static bool isalpha([NotNone] this string self) {
             return true;
         }
 
+        // new in Python 3.7
         public static bool isascii([NotNone] this string self) {
             foreach (char c in self) {
                 if (c > 0x7f) return false;

tests/suite/modules/network_related/test__socket.py

@@ -352,12 +352,29 @@ def test_getnameinfo(self):
         host, service = _socket.getnameinfo( ("127.0.0.1", 80), 0)
         self.assertEqual(service, "http")
         #IP gives a TypeError
-        #self.assertRaises(SystemError, _socket.getnameinfo, ("127.0.0.1"), 8)
-        #self.assertRaises(SystemError, _socket.getnameinfo, (321), 8)
+        self.assertRaises(TypeError, _socket.getnameinfo, ("127.0.0.1"), 8)
+        self.assertRaises(TypeError, _socket.getnameinfo, (321), 8)
         self.assertRaises(TypeError, _socket.getnameinfo, ("127.0.0.1"), '0')
         self.assertRaises(TypeError, _socket.getnameinfo, ("127.0.0.1", 80, 0, 0, 0), 8)
         self.assertRaises(_socket.gaierror, _socket.getnameinfo, ('no such host will ever exist', 80), 8)
 
+        # try some IPv6 cases
+        ports = {
+            80: "http",
+            443: "https",
+        }
+
+        addresses = ["::1", "::", "::0"]
+        address_num = {"::0": "::"}
+
+        for address in addresses:
+            for port, port_name in ports.items():
+                res = _socket.getnameinfo((address, port), 0)
+                # don't check the host name, unreliable across platforms
+                self.assertEqual(res[1], port_name)
+                res = _socket.getnameinfo((address, port), _socket.NI_NUMERICHOST | _socket.NI_NUMERICSERV)
+                self.assertEqual(res, (address_num.get(address, address), str(port)))
+
     def test_gethostbyaddr(self):
         '''Tests _socket.gethostbyaddr'''
         _socket.gethostbyaddr("localhost")

tests/suite/test_socket_stdlib.py

@@ -41,10 +41,6 @@ def load_tests(loader, standard_tests, pattern):
             failing_tests += [
                test.test_socket.NonBlockingTCPTests('testRecv'), # TODO: figure out
             ]
-        if not is_mono:
-            failing_tests += [
-                test.test_socket.GeneralModuleTests('test_getnameinfo'), # https://github.com/IronLanguages/ironpython3/issues/1222
-            ]
         if is_linux:
             failing_tests += [
                 test.test_socket.GeneralModuleTests('test_idna'), # TODO: figure out