Monday, January 24, 2011

First practical joke with gncci - clamping the MSS

Today I thought that a great hack might be to try out per-host MSS clamping in userland.

Sounds like a fun idea, but ideas are not much without the execution - so this diff adds the hook for the setsockopt() - and, as a side effect the o.setsockopt() into the Lua-land. (The latter was actually what I wanted, but it was silly not to add the whole hook).

The result - it does wonders with PMTUD-blackholed websites, the world becomes wonderful again. All of this even without needing root to tweak the MTU on the physical interface.

Look, ma, no hands!

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