we want to be able to have multiple locally bound dns sockets in lokinet so
i restructured most of the dns subsystem in order to make this easier.
specifically, we have a new structure to dns subsystem:
* dns::QueryJob_Base
base type for holding a dns query and response with virtual methods
in charge of sending a reply to whoever requested.
* dns::PacketSource_Base
base type for reading and writing dns messages to and from wherever they came from
* dns::Resolver_Base
base type for filtering and handling of dns messages asynchronously.
* dns::Server
contextualized per endpoint dns object, responsible for all dns related isms.
this change hides all impelementation details of all of the dns components.
adds some more helper functions for parsing dns and dealing with OwnedBuffer.
overall dns becomes less of a pain with this new structure. probably.
- removes all the llarp_ev_* functions, replacing with methods/classes/functions in the llarp
namespace.
- banish ev/ev.h to the void
- Passes various things by const lvalue ref, especially shared_ptr's that don't need to be copied
(to avoid an atomic refcount increment/decrement).
- Add a llarp::UDPHandle abstract class for UDP handling
- Removes the UDP tick handler; code that needs tick can just do a separate handler on the event
loop outside the UDP socket.
- Adds an "OwnedBuffer" which owns its own memory but is implicitly convertible to a llarp_buffer_t.
This is mostly needed to take over ownership of buffers from uvw without copying them as,
currently, uvw does its own allocation (pending some open upstream issues/PRs).
- Logic:
- add `make_caller`/`call_forever`/`call_every` utility functions to abstract Call wrapping and
dependent timed tasks.
- Add inLogicThread() so that code can tell its inside the logic thread (typically for
debugging assertions).
- get rid of janky integer returns and dealing with cancellations on call_later: the other methods
added here and the event loop code remove the need for them.
- Event loop:
- redo everything with uvw instead of libuv
- rename EventLoopWakeup::Wakeup to EventLoopWakeup::Trigger to better reflect what it does.
- add EventLoopRepeater for repeated events, and replace the code that reschedules itself every
time it is called with a repeater.
- Split up `EventLoop::run()` into a non-virtual base method and abstract `run_loop()` methods;
the base method does a couple extra setup/teardown things that don't need to be in the derived class.
- udp_listen is replaced with ev->udp(...) which returns a new UDPHandle object rather that
needing gross C-style-but-not-actually-C-compatible structs.
- Remove unused register_poll_fd_(un)readable
- Use shared_ptr for EventLoopWakeup rather than returning a raw pointer; uvw lets us not have to
worry about having the event loop class maintain ownership of it.
- Add factory EventLoop::create() function to create a default (uvw-based) event loop (previously
this was one of the llarp_ev_blahblah unnamespaced functions).
- ev_libuv: this is mostly rewritten; all of the glue code/structs, in particular, are gone as
they are no longer needed with uvw.
- DNS:
- Rename DnsHandler to DnsInterceptor to better describe what it does (this is the code that
intercepts all DNS to the tun IP range for Android).
- endpoint:
- remove unused "isolated network" code
- remove distinct (but actually always the same) variables for router/endpoint logic objects
- llarp_buffer_t
- make constructors type-safe against being called with points to non-size-1 values
- tun packet reading:
- read all available packets off the device/file descriptor; previously we were reading one packet
at a time then returning to the event loop to poll again.
- ReadNextPacket() now returns a 0-size packet if the read would block (so that we can implement
the previous point).
- ReadNextPacket() now throws on I/O error
- Miscellaneous code cleanups/simplifications
