多线程Python端口扫描器

Question

我在修改一个端口扫描器，想让它使用多线程，但遇到了一些问题。

这是原始代码的基本部分：

for i in range(0, 2000):  

    s = socket(AF_INET, SOCK_STREAM)  
    result = s.connect_ex((TargetIP, i))  

    if(result == 0) :  
        c = "Port %d: OPEN\n" % (i,)  

    s.close()

这个代码大约需要33分钟才能完成。所以我想用多线程来让它运行得快一点。这是我第一次做多线程的项目，所以也不是特别复杂。但是我运行了以下代码大约一个小时，既没有出现错误，也没有任何输出。我是在多线程方面做错了什么吗？

import threading
from socket import *
import time

a = 0
b = 0
c = ""
d = ""

def ScanLow():
    global a
    global c

    for i in range(0, 1000):  
        s = socket(AF_INET, SOCK_STREAM)  
        result = s.connect_ex((TargetIP, i))  

        if(result == 0) :  
            c = "Port %d: OPEN\n" % (i,)  

        s.close()  
        a += 1

def ScanHigh():
    global b
    global d

    for i in range(1001, 2000):  
        s = socket(AF_INET, SOCK_STREAM)  
        result = s.connect_ex((TargetIP, i))  

        if(result == 0) :  
            d = "Port %d: OPEN\n" % (i,)  

        s.close()  
        b += 1

Target = raw_input("Enter Host To Scan:")
TargetIP = gethostbyname(Target)

print "Start Scan On Host ", TargetIP
Start = time.time()

threading.Thread(target = ScanLow).start()
threading.Thread(target = ScanHigh).start()

e = a + b

while e < 2000:
    f = raw_input()

End = time.time() - Start
print c
print d
print End

g = raw_input()

Answer 1

你现在的方法有点尴尬，用来监控线程。使用 join 可以知道线程什么时候完成。其实没有理由不多开几个线程，这样可以更快得到结果：

import threading
import socket
import time

ports = []
def check_port(ip,port):
    s = socket.socket()
    if s.connect_ex((ip,port)) == 0:
        ports.append(port)
    s.close()

target = raw_input('Target? ')
s = time.time()
threads = []
for port in range(2000):
    t = threading.Thread(target=check_port,args=(target,port))
    t.start()
    threads.append(t)
for t in threads:
    t.join()
print ports
print time.time() - s

输出

[80, 135, 445, 1028]
6.92199993134

Answer 2

这是你的代码出问题的地方。

threading.Thread(target = ScanLow).start()
threading.Thread(target = ScanHigh).start()

e = a + b

while e < 2000:
   f = raw_input()

在你启动线程之后，你把值设置为 e。但是之后你从来没有更新过 e，所以循环就一直不会结束。

看起来你是想等两个线程都完成。其实可以用 join() 方法来更好地实现这个功能。

from threading import Thread
threads = []
threads.append(Thread(target = ScanLow))
threads.append(Thread(target = ScanHigh))
for thread in threads:
  thread.start()
//both threads are running
for thread in threads:
  thread.join()
//both threads have stopped

补充： 这和你的问题无关，但这是个有用的建议。你两个扫描函数做的事情完全一样。你可以用一个函数来替代它们，这个函数可以接收扫描范围作为参数，然后用这个函数启动两个线程。

from threading import Thread
def Scan(start, stop):
    global a
    global c

    for i in range(start, stop):  
        s = socket(AF_INET, SOCK_STREAM)  
        result = s.connect_ex((TargetIP, i))  

        if(result == 0) :  
            c = "Port %d: OPEN\n" % (i,)  

        s.close()  
        a += 1

threadCount = 2
totalPorts = 2000
threads = []
for start in xrange(0, totalPorts, totalPorts/threadCount):
    threads.append(Thread(target = Scan, args = (start, totalPorts/threadCount)))

for thread in threads:
  thread.start()
//both threads are running
for thread in threads:
  thread.join()
//both threads have stopped

这样你就可以很方便地调整线程和要扫描的端口数量了。