This mainly saves spam in test logs, but may save some packets here and
there, if nodes are randomly selected twice for GET_NODES and onion
routing packets.
This fixes an error reported by cppcheck about overflowing the callback
array. The locking logic probably was broken, so I replaced it with
something simpler and more robust.
The idea here is to have a `Network` object that contains functions for
network operations and an optional userdata object that can manage those
network operations. This allows e.g. a fuzzer to replace the network
functions with no-ops or fuzzer inputs, reducing the need for `#ifdef`s.
As a side-effect, DHT now always accepts LAN discovery packets, even
when LAN discovery is disabled. When LAN discovery is disabled, those
packets are ignored.
This aligns the autotools build with the cmake build, which doesn't have
a config.h file. It also removes the ambiguity of config.h and
other/bootstrap_daemon/src/config.h.
This forces all the loop bodies to be executed at least once, which is
harmless since it just means one more tox event loop iteration. This
reduces the jitter we see in coverage measurements, which is partially
caused by loops sometimes being entered and sometimes not (because their
condition happens to randomly already be true).
Reduced by, e.g.:
* `file_transfer_test`: 33% of the `clock_gettime` calls.
* `tox_many_test`: 53% of the `clock_gettime` calls.
Other tests will see similar improvements. Real world applications will
be closer to 40-50% improvement, since tox_many_test has 100 nodes, while
file_transfer_test has 2 nodes.
It turns out, `unix_time` is also monotonic, and is used as such, so I've
renamed the new functions to `mono_time_*`.
2018-07-08:
```
00:01 <@irungentoo> the idea used to be that the unix_time() function
could go backward in time but I think I might have started using it like
if it could not after I changed it so that it would never go back in time
```
Rules:
1. Constants are uppercase names: THE_CONSTANT.
2. SUE[1] types start with an uppercase letter and have at least one
lowercase letter in it: The_Type, THE_Type.
3. Function types end in "_cb": tox_friend_connection_cb.
4. Variable and function names are all lowercase: the_function.
This makes it easier for humans reading the code to determine what an
identifier means. I'm not convinced by the enum type name change, but I
don't know a better rule. Currently, a lot of enum types are spelled like
constants, which is confusing.
[1] struct/union/enum
Tests are not actually ran on appveyor for now, since they all fault for
some reason. For now, we just build them. Also, some tests are disabled
on msvc entirely, because they don't even compile. We'll need to look
into those, later. They are disabled using `MSVC_DONT_BUILD`.
