Linux Kernel : IP Identification header generation code in linux kernel source code

问题

Hi I am playing with Linux Kernel Source code, I want to know where the IP Identification Header generated in linux source code kernel, and what function or formula to generate it,

This IP Identification is descripted in this image example format

http://telescript.denayer.wenk.be/~hcr/cn/idoceo/images/ip_header.gif

I already know the other value generated in TCP Stack like TCP Initial Sequence Number,

来源：https://stackoverflow.com/questions/56149288/linux-kernel-ip-identification-header-generation-code-in-linux-kernel-source-c