最有效的方式来操作TCP头ISN号 [英] Most efficient way to manipulate ISN numbers in TCP headers
问题描述
我目前正在写一个程序，将能够创造稳定的TCP连接，并有超过ISN号码完全控制。我用C写，我在那里我认识非常有限已经达到极限了点，我想知道是否有这样做的更好的方法。
I am currently trying to write a program that will be able to create stable a TCP connection and have complete control over the ISN numbers. I've been writing in C and I am at a point where my very limited knowledge has reached its limits and I was wondering if there's a better way of doing it.
我试过手动构建头，采用原始套接字没有内核的干扰，这是一个挑战发送和接收数据包。
What I tried was building the headers manually, using raw sockets to send and recieve the packets without the kernel interfering, which is a challenge.
因此，无论语言，有什么事你看是操纵ISN的最有效和最简单的方法是什么？
So regardless of language, what do you reckon is the most efficient and easiest way of manipulating the ISN?
推荐答案
那么，ISN是随机的方式prevent ISN perediction攻击generatred（的 http://www.thegeekstuff.com/2012/01/tcp-sequence-number-attacks/ ）。
Well, ISN is generatred in a random way to prevent ISN perediction attack (http://www.thegeekstuff.com/2012/01/tcp-sequence-number-attacks/).
Linux的网络协议栈，使用功能 tcp_v4_init_sequence 来生成ISN（的 http://lxr.free-electrons.com/source/net/ipv4/tcp_ipv4.c#L101 ），这个函数调用 secure_tcp_sequence_number 函数（ HTTP： //lxr.free-electrons.com/source/net/core/secure_seq.c#L106 ）来完成这项工作。看看此功能，并尝试克隆它，以便在与用户空间的code使用它。
The Linux Network stack, use the function tcp_v4_init_sequence to generate the ISN (http://lxr.free-electrons.com/source/net/ipv4/tcp_ipv4.c#L101), this function call secure_tcp_sequence_number function (http://lxr.free-electrons.com/source/net/core/secure_seq.c#L106) to do the job. Take a look at this function and try to clone it so can use it with your code from userspace.
如果你有足够的时间，你可以看看 RFC 6528的部分3 （ http://www.rfc-editor.org/rfc/rfc6528.txt ），它描述了如何生成ISN的算法
If you have enough time you can look at section 3 of the RFC 6528 (http://www.rfc-editor.org/rfc/rfc6528.txt), it describe an algorithm on how to generate ISN:
ISN = M + F(localip, localport, remoteip, remoteport, secretkey)
和努力实现它，如果你想：）
And try to implement it, if you want :)
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