Move guard state out of globals per new guard plan

New guard plan summarized here at https://lists.torproject.org/pipermail/tor-dev/2016-July/011234.html

1. Create main guard selection state data structure (instead of using global variables)

• Ideally there should be no global variables, so that in the future we can have multiple parallel guardsets (e.g. prop247)
• Thoughtworks: guard_selection_t

changed milestone to %Tor: 0.3.0.x-final

added actualpoints::6 component::core tor/tor milestone::Tor: 0.3.0.x-final nickm-deferred-20161005 owner::andrea parent::19877 points::3 priority::medium resolution::implemented severity::normal sponsor::U-must status::closed type::task version::tor unspecified labels

Trac:
Parent: N/A to #19877 (moved)

Trac:
Sponsor: SponsorU to SponsorU-must

This is done in my ticket19858 branch now. For now existing calls into entryguards.c just use the default guard context; later on we'll need to figure out which call sites care about using a particular one once we have particular ones.

Trac:
Status: new to needs_review
Actualpoints: N/A to 6

Thanks! Would you like to make a gitlab pull request for this so it's easier for me to review? Or should I?

https://gitlab.com/nickm_tor/tor/merge_requests/9 is the gitlab link

I noted a couple of small revisions on the gitlab link. Should be pretty quick. Thanks!

Trac:
Status: needs_review to needs_revision

Deferring big/risky-feature things (even the ones I really love!) to 0.3.0. Please argue if I'm wrong.

Trac:
Keywords: N/A deleted, nickm-deferred-20161005 added
Milestone: Tor: 0.2.9.x-final to Tor: 0.3.0.x-final

My ticket19858_v2 branch has revisions from gitlab now

Trac:
Status: needs_revision to needs_review

Trac:
Cc: N/A to asn

lgtm

Trac:
Status: needs_review to merge_ready

Merged!

Trac:
Status: merge_ready to closed
Resolution: N/A to implemented

closed

changed time estimate to 24h

added 48h of time spent

mentioned in issue #20410 (moved)

moved to tpo/core/tor#19858 (closed)

mentioned in issue tpo/core/tor#20410 (closed)