Port-sniffer homework

submissions/mazzart/port-sniffer/sniffer.py

@@ -0,0 +1,78 @@
+import argparse
+import socket
+import sys
+
+
+def argument_parser():
+    """Initialize argument parser"""
+
+    script_description = "Sniffer is tool which allows user to easily " \
+                         "search for opened TCP ports on particular host"
+
+    parser = argparse.ArgumentParser(description=script_description)
+    parser.add_argument('--host', type=str, nargs='?', required=True,
+                        help='enter domain name or IP address to search')
+    parser.add_argument('--ports', type=str, nargs='?', default='0-65535',
+                        help='limit the range of ports to scan, '
+                             'use the format: <start_port>-<end_port>')
+
+    return parser
+
+
+def ports_scanner(host: str, ports: str) -> list:
+    """Scans and saves open TCP ports"""
+
+    buffer = []
+    start, end = ports.split('-')
+    start, end = int(start), int(end)
+
+    try:
+        for port in range(start, end+1):
+            with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+                sock.settimeout(0.3)
+                conn = sock.connect_ex((host, port))
+                if conn == 0:
+                    print('.', end='')
+                    buffer.append(port)
+                else:
+                    continue
+
+    except KeyboardInterrupt:
+        print("\nYou printed Ctrl+C")
+        sys.exit(1)
+    except socket.gaierror:
+        print("Hostname could not be resolved")
+        sys.exit(1)
+    except socket.error as error:
+        print(error)
+        sys.exit(1)
+
+    return buffer
+
+
+def show_ports(ports_list: list):
+    """Prints ports info"""
+
+    if ports_list:
+        print()
+        for port in ports_list:
+            print(port, end=',')
+        print(' ports are opened')
+    else:
+        print('There are no open ports')
+
+    sys.exit(0)
+
+
+def main():
+    """Script entry point"""
+
+    args = argument_parser().parse_args()
+    argv = vars(args)
+    host, ports = argv['host'], argv['ports']
+    open_ports = ports_scanner(host, ports)
+    show_ports(open_ports)
+
+
+if __name__ == "__main__":
+    main()