Question

我正在解析一个大文本文件以获得正确的TCP连接，我需要做的一件事就是检查服务器和主机IP地址（有30个不同的主机）是否已经相互发送了一个SYN数据包。

主持人名单：

HostList1 =   ['150.100.12.130','150.100.12.131','150.100.12.132','150.100.12.133','150.100.12.134','150.100.12.135','150.100.12.136','150.100.12.137','150.100.12.138','150.100.12.139']

来自文本的示例行（有数千行）：

2.000724 IP (tos 0x0, ttl  63, id 0, offset 0, flags [none], proto: TCP (6), length: 40, bad cksum 0 (->4280)!) 150.100.12.134.49153 > 150.100.0.2.57300: S, cksum 0x0000 (incorrect (-> 0xd6bb), 0:0(0) win 65535
2.000724 IP (tos 0x0, ttl  64, id 17, offset 0, flags [none], proto: TCP (6), length: 40, bad cksum 0 (->416f)!) 150.100.0.2.57300 > 150.100.12.134.49153: S, cksum 0x0000 (incorrect (-> 0xd6aa), 0:0(0) ack 1 win 65535

我当前的代码，服务器地址是150.100.0.2：

with open("serverLanTraceWithErrors.txt" , "r") as ParseFile1:
   for line in ParseFile1:
     if 'TCP' in line:               #Check if TCP proto is in the line
      Split1 = line.split(",")       #Split each line by a comma for future splits                                       
      Split2 = Split1[7].split(">")  #Split1[7] contains the two IP addresses, host and server and the direction of the packet
      Split3 = Split1[1].split(" ")  #Split3[3] will show the # hops 

      for item in HostList1:
          if 'S' in line:            #check if SYN flag is in the line

            if item in Split2[1] and '150.100.0.2' in Split2[2] and '63' in Split3[3]:
               print("SYN packet from host computer: %s to server completed with right # of hops %s" %(item, Split3[3]))

            elif item in Split2[2] and  '150.100.0.2' in Split2[1] and '64' in Split3[3] and 'ack' in Split1[9]:
               print("SYN packet from server to host computer: %s completed with right # of hops %s" %(item, Split3[3])) 

            elif: item hasn't been found sending or receving SYN flag...
               print("SYN pack from wherever to wherever not completed...")

理想情况下，应该有两种情况，即在服务器和主机之间找到SYN标志。主机到服务器和服务器回主机。我的问题是我无法找到使最后一个elif语句工作的方法，我需要一种方式来说，如果两个顶级语句中只有一个发生了它发生的IP地址。因为对于主机150.100.12.139，它只发送一个数据包到主机，主机永远不会回复一个，我的代码能够指出它。我对python的了解非常有限，所以我一直坐在这里难倒了一会儿。

Answer 1

你说＆＃34; 理想情况下，应该有两种情况，即在服务器和主机之间找到SYN标志＆＃34;所以我猜测最后一个elif条件是检查上述条件之一是否有效。我建议使用elif而不是上一次else语句，如下所示。

for item in HostList1:
          if 'S' in line:            #check if SYN flag is in the line

            if item in Split2[1] and '150.100.0.2' in Split2[2] and '63' in Split3[3]:
               print("SYN packet from host computer: %s to server completed with right # of hops %s" %(item, Split3[3]))

            elif item in Split2[2] and  '150.100.0.2' in Split2[1] and '64' in Split3[3] and 'ack' in Split1[9]:
               print("SYN packet from server to host computer: %s completed with right # of hops %s" %(item, Split3[3])) 

            else:  ## item hasn't been found sending or receving SYN flag...
               print("SYN pack from wherever to wherever not completed...")

让我知道它是否对你有帮助。

编辑1：在查看评论后，我建议你以下

            if item in Split2[1] and '150.100.0.2' in Split2[2] and '63' in Split3[3]:
               print("SYN packet from host computer: %s to server completed with right # of hops %s" %(item, Split3[3]))

            elif item in Split2[2] and  '150.100.0.2' in Split2[1] and '64' in Split3[3] and 'ack' in Split1[9]:
               print("SYN packet from server to host computer: %s completed with right # of hops %s" %(item, Split3[3])) 

            elif item not in Split2[1] or item in Split2[2] :  ## item hasn't been found sending or receving SYN flag...
               print("SYN pack from wherever to wherever not completed...")

如果是文本解析的语句困境

1 个答案: