CODEWITHSUNDEEP
linuxtcplinux-kernel
sntc06
sntc06

Reputation: 23

Bypass TCP three way handshaking?

Is it possible to make a system call or write a kernel module to craft a tcp connection right into ESTABLISHED state without going over the three way handshaking process, assuming the correct SYN-seq and ack number are provided dynamically?

Upvotes: 2

Views: 2249

Answers (1)

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136505

You may like to have a look at TCP fast open, which modern Linux kernels implement:

TCP Fast Open (TFO) is an extension to speed up the opening of successive Transmission Control Protocol (TCP) connections between two endpoints. It works by using a TFO cookie (a TCP option) in the initial SYN packet to authenticate a previously connected client. If successful, it may start sending data to the client before the receipt of the final ACK packet of the three way handshake is received, skipping a round trip and lowering the latency in the start of transmission of data.

Upvotes: 5

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