add address check functions

.gitignore

@@ -1,5 +1,6 @@
 # Byte-compiled / optimized / DLL files
 __pycache__/
+.idea/
 *.py[cod]
 *$py.class
 

lightsocks/utils/addr_check.py

@@ -0,0 +1,49 @@
+# coding:utf-8
+"""
+Check the availability of IP and port.
+Author: kerbalwzy@gmail.com
+Date: 2019-07-08
+"""
+
+import socket
+
+
+def _host_addresses() -> set:
+    """
+    Get the all addresses of the host, just include IPV4
+    :return: address
+    """
+    address = socket.getaddrinfo(socket.gethostname(), None)
+    address = [item[4][0] for item in address if ':' not in item[4][0]]
+    address.extend(["127.0.0.1", "0.0.0.0"])
+    return set(address)
+
+
+def ip_validate(ip: str) -> bool:
+    """
+    The ip is require be one of the host addresses
+    :param ip: string, the ip need to be check
+    :return: boolean value
+    """
+    return ip in _host_addresses()
+
+
+def _port_is_free(port: int) -> bool:
+    """
+    Try connect a local port. If success meanings the port is using.
+    :param port: int, the port need be check.
+    :return: boolean value.
+    """
+    with socket.socket() as s:
+        s.settimeout(0.5)
+        # s.connect_ex return 0 means port is open and using
+        return s.connect_ex(('localhost', port)) != 0
+
+
+def port_validate(port: int) -> bool:
+    """
+    The port is required in range 1024 to 65535, and spare.
+    :param port: int, the port need be check
+    :return: boolean value
+    """
+    return 1023 < port < 65536 and _port_is_free(port)

lightsocks/utils/net.py

@@ -1,4 +1,3 @@
 from collections import namedtuple
 
-
-Address = namedtuple('Address', 'ip port')
+Address = namedtuple('Address', 'ip port')

lightsocks/utils/test_addr_check.py

@@ -0,0 +1,22 @@
+# coding:utf-8
+"""
+Check the availability of IP and port.
+Author: kerbalwzy@gmail.com
+Date: 2019-07-08
+Note: 单元测试运行会把 "函数注解" 识别为语法错误，如果你要运行，请先在代码中删除函数注解
+"""
+
+import unittest
+from lightsocks.utils.addr_check import ip_validate, port_validate
+
+
+class UtilsAddrCheckTest(unittest.TestCase):
+    def test_ip_validate(self):
+        self.assertTrue(ip_validate("127.0.0.1"))
+        self.assertTrue(ip_validate("0.0.0.0"))
+        self.assertFalse(ip_validate("abc"))
+        self.assertFalse(ip_validate("127.0.0.256"))
+
+    def test_port_validate(self):
+        self.assertFalse(port_validate(22))
+        self.assertFalse(port_validate(1023))