Fix kernel version check for TCP_FASTOPEN support

[BeardOverflow]

Identify the Bug

https://github.com/etr/libhttpserver/issues/346

Description of the Change

TCP_FASTOPEN should be enabled based on the Linux kernel version. The current implementation is incorrectly evaluating some kernel versions and is failing to correctly handle minor version lower than 7 for major versions greater than 3.

For example, kernel versions 6.1 and 6.6 were incorrectly excluded, even though they do support TCP_FASTOPEN, just because its minor version is lower than 7.

Alternate Designs

None.

Possible Drawbacks

None.

Verification Process

I have used GitHub search engine and git blame command line.

The first commit introducing this kernel version check was authored 10 years ago: https://github.com/etr/libhttpserver/commit/a73055165b18d6818cf5e178a155ad5343868f08 The first commit suggests Kernel 3.6 to support TCP_FASTOPEN, but a newer commit change it to 3.7: https://github.com/etr/libhttpserver/commit/8786b2f4c910a69cec0095e4a8bc732cce919d50

No more related commits.

Release Notes

• Fixed kernel version check for TCP_FASTOPEN support