Apparently, MS C is #defining "IN" on us, so we can't name a
variable IN.  Delightful!

If somebody's excludenodes settings are keeping their hidden service
connections from working, they should probably get notified about it.

Sebastian Hahn authored 11 years ago and Nick Mathewson committed 11 years ago

clang 3.4 introduced a new by-default warning about unused static
functions, which we triggered heavily for the hashtable and map function
generating macros. We can use __attribute__ ((unused)) (thanks nickm for
the suggestion :-) ) to silence these warnings.

When we have more than two return values, we should really be using
an enum rather than "-2 means this, -1 means that, 0 means this, and
1 or more means a number."

Noted by Nick on #10841.

The latest GeoLite2 database includes a pointer from 2001::/32 to the root
node of the IPv4 address space in the tree.  We need to exclude this whole
address space from geoip6, similar to how we exclude IPv4-mapped IPv6
addresses and the 6to4 mapping subnet.

This completes our conversion to using siphash for our hash functions.

It's increasingly apparent that we want to make sure we initialize our
PRNG nice and early, or else OpenSSL will do it for us.  (OpenSSL
doesn't do _too_ bad a job, but it's nice to do it ourselves.)

We'll also need this for making sure we initialize the siphash key
before we do any hashes.

I've made an exception for cases where I'm sure that users can't
influence the inputs.  This is likely to cause a slowdown somewhere,
but it's safer to siphash everything and *then* look for cases to
optimize.

This patch doesn't actually get us any _benefit_ from siphash yet,
since we don't really randomize the key at any point.

siphash is a hash function designed for producing hard-to-predict
64-bit outputs from short inputs and a 128-bit key.  It's chosen for
security and speed.

See https://131002.net/siphash/ for more information on siphash.

Source: https://github.com/majek/csiphash/

There is no WSAEPERM; we were implying that there was.This fixes a
bug in e0c80315, which hadn't yet
appeared in any released Tor.

Fixes the rest of #10841 after #10881 already removed some hidden service
authority code.