#!/usr/bin/env python3
import socket
import argparse

def scan(host, port, banner, timeout):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(timeout)
    try:
        err = s.connect_ex((host, port))
        if err == 111:
            return "closed", b""
        if err != 0:
            return "filtered", b""
        try:
            s.sendall(banner)
        except:
            print("Error sending")
        try:
            data = s.recv(1024)
        except:
            data = b"error receiving"
        return "open", data
    finally:
        s.close()

def main():
    p = argparse.ArgumentParser()
    p.add_argument("host")
    p.add_argument("-P", "--ports", default="22,80,443")
    p.add_argument("-b", "--banner", default="GET / ")
    p.add_argument("-t", "--timeout", type=float, default=1.0)
    a = p.parse_args()

    ports = [int(x) for x in a.ports.split(",") if x.strip()]
    banner = a.banner.encode()

    for port in ports:
        state, data = scan(a.host, port, banner, a.timeout)
        if state == "open":
            print(f"{port} open       {data.decode('utf-8', 'replace').strip()}")
        else:
            print(f"{port} {state}")

if __name__ == "__main__":
    main()