Limit number of concurrent p2p UDP sockets.

This guards against a resource exhaustion in the
UNIX sockets space.

Bug: chromium:826957
Change-Id: I0b55ff033812b1778793f0d27398012c557b8e3a
Reviewed-on: https://chromium-review.googlesource.com/995433
Reviewed-by: Jochen Eisinger <[email protected]>
Reviewed-by: Tommi <[email protected]>
Commit-Queue: Harald Alvestrand <[email protected]>
Cr-Commit-Position: refs/heads/master@{#550145}
5 files changed