To make sure that a server learns if its IP has changed, the server
sometimes launches authority.z descriptor fetches from
update_router_descriptor_downloads. That's nice, but we're moving
towards a situation where update_router_descriptor_downloads doesn't
always get called. So this patch breaks the authority.z
check-and-fetch into a new function.
This function also renames last_routerdesc_download to a more
appropriate last_descriptor_download, and adds a new
update_all_descriptor_downloads() function.
(For now, this is unnecessary, since servers don't actually use
microdescriptors. But that could change, or bridges could start
using microdescriptors, and then we'll be glad this is refactored
nicely.)
To turn this on, set UseMicrodescriptors to "1" (or "auto" if you
want it on-if-you're-a-client). It should go auto-by-default once
0.2.3.1-alpha is released.
Because of our node logic, directory caches will never use
microdescriptors when they have the right routerinfo available.
See bug 2850 for rationale: it appears that on some busy exits, the OS
decides that every single port is now unusable because they have been
all used too recently.
Previously we ensured that it would get called periodically by doing
it from inside the code that added microdescriptors. That won't work
though: it would interfere with our code that tried to read microdescs
from disk initially. Instead, we should consider rebuilding the cache
periodically, and on startup.
Previously on 0.2.2, we'd never clean the cache. Now that we can
clean it, we want to add a condition to rebuild it: that should happen
whenever we have dropped enough microdescriptors that we could save a
lot of space.
No changes file, since 0.2.3 doesn't need one and 0.2.2 already has some
changes files for the backport of the microdesc_clean_cahce() function.
n_supported[i] has a random value prior to initialization, so a node
that doesn't have routerinfo available can have a random priority.
Patch contributed by wanoskarnet from #tor. Thanks!
Otherwise I need to figure out what it does and how to make it do it
every time I want to use it. It did that unixy thing where running
it with no arguments printed nothing and returned.
