用python写的一个多线程的端口扫描

#!/usr/bin/env pythonimport socketimport sysimport threadingimport timeNORMAL = 0ERROR = 1TIMEOUT = 5def ping(ip , port , timeout=TIMEOUT):try:cs=socket.socket(socket.AF_INET,socket.SOCK_STREAM)cs.settimeout(float(timeout))address=(str(ip),int(port))status = cs.connect_ex((address))if status == NORMAL :print "%d is NORMAL" %portexcept Exception ,e:print ERRORprint "error:%s" %ereturn ERRORcs.close()return NORMAL class Scan(threading.Thread):    def __init__(self , ip , timeout):        threading.Thread.__init__(self)self.ip = ipself.timeout = timeout    def run(self):        global p_begin , p_end , mutex        threadname = threading.currentThread().getName()        while 1:            mutex.acquire()            p_begin += 1            if p_begin >  p_end:    mutex.release()    break            mutex.release()    ping(self.ip , p_begin , self.timeout) if __name__ == '__main__':    if len(sys.argv) < 4:print 'format:urlbegin portbegin portend timeout'    urlbegin = str(sys.argv[1])    portbegin = int(sys.argv[2])    portend = int(sys.argv[3])    timeout = float(sys.argv[4])    global p_begin , p_end, mutex    threads = []    num = 10    p_begin = portbegin     p_end = portend    mutex = threading.Lock()    for x in xrange(0 , num):        t_scan = Scan(urlbegin , timeout)t_scan.setDaemon(True)        threads.append(t_scan)    for t in threads:        t.start()    for t in threads:        t.join()