This is the "server-side" part of the new friend finding system,
allowing DHT nodes to store small amounts of data and permit searching
for it. A forwarding (proxying) mechanism allows this to be used by TCP
clients, and deals with non-transitivity in the network.
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.
It was kind of thread-safe, maybe, but there was a data race that makes
tsan unhappy. We now do interface detection once per Tox instance
instead of once per process.
Use of `strcpy` in these particular cases was safe, but it's hard to
tell and also useless. `strcpy` would effectively need to do another
`strlen` which we already did.
Also removed sprintf, which was also safe in this case but it's easier to
be "obviously safe", especially for static analysers.
atoi doesn't check if the conversion from string to int succeeded
which doesn't allow us to do proper error handling.
We also now make sure that the port argument is a valid port
in addition to being properly converted
Don't know why codes with macro dosen't work.
As it's only a few expensive, just code it without macro for now.
\#if (MIN_LOGGER_LEVEL == LOG_TRACE) || (MIN_LOGGER_LEVEL == LOG_DEBUG)
fprintf(stderr, "[%s] %s:%d(%s) %s\n", strlevel, file, line, func, message);
\#endif
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
