lokinet/llarp/router/outbound_message_handler.hpp
Jason Rhinelander b4440094b0 De-abseil, part 2: mutex, locks, (most) time
- util::Mutex is now a std::shared_timed_mutex, which is capable of
  exclusive and shared locks.

- util::Lock is still present as a std::lock_guard<util::Mutex>.

- the locking annotations are preserved, but updated to the latest
  supported by clang rather than using abseil's older/deprecated ones.

- ACQUIRE_LOCK macro is gone since we don't pass mutexes by pointer into
  locks anymore (WTF abseil).

- ReleasableLock is gone.  Instead there are now some llarp::util helper
  methods to obtain unique and/or shared locks:
    - `auto lock = util::unique_lock(mutex);` gets an RAII-but-also
      unlockable object (std::unique_lock<T>, with T inferred from
      `mutex`).
    - `auto lock = util::shared_lock(mutex);` gets an RAII shared (i.e.
      "reader") lock of the mutex.
    - `auto lock = util::unique_locks(mutex1, mutex2, mutex3);` can be
      used to atomically lock multiple mutexes at once (returning a
      tuple of the locks).
  This are templated on the mutex which makes them a bit more flexible
  than using a concrete type: they can be used for any type of lockable
  mutex, not only util::Mutex.  (Some of the code here uses them for
  getting locks around a std::mutex).  Until C++17, using the RAII types
  is painfully verbose:

  ```C++
  // pre-C++17 - needing to figure out the mutex type here is annoying:
  std::unique_lock<util::Mutex> lock(mutex);
  // pre-C++17 and even more verbose (but at least the type isn't needed):
  std::unique_lock<decltype(mutex)> lock(mutex);
  // our compromise:
  auto lock = util::unique_lock(mutex);
  // C++17:
  std::unique_lock lock(mutex);
  ```

  All of these functions will also warn (under gcc or clang) if you
  discard the return value.  You can also do fancy things like
  `auto l = util::unique_lock(mutex, std::adopt_lock)` (which lets a
  lock take over an already-locked mutex).

- metrics code is gone, which also removes a big pile of code that was
  only used by metrics:
  - llarp::util::Scheduler
  - llarp:🧵:TimerQueue
  - llarp::util::Stopwatch
2020-02-21 23:22:47 -04:00

156 lines
3.6 KiB
C++

#ifndef LLARP_ROUTER_OUTBOUND_MESSAGE_HANDLER_HPP
#define LLARP_ROUTER_OUTBOUND_MESSAGE_HANDLER_HPP
#include <router/i_outbound_message_handler.hpp>
#include <util/thread/logic.hpp>
#include <util/thread/queue.hpp>
#include <util/thread/threading.hpp>
#include <path/path_types.hpp>
#include <router_id.hpp>
#include <list>
#include <unordered_map>
#include <utility>
struct llarp_buffer_t;
namespace llarp
{
struct ILinkManager;
class Logic;
enum class SessionResult;
struct OutboundMessageHandler final : public IOutboundMessageHandler
{
public:
~OutboundMessageHandler() override = default;
OutboundMessageHandler(size_t maxQueueSize = MAX_OUTBOUND_QUEUE_SIZE);
bool
QueueMessage(const RouterID &remote, const ILinkMessage *msg,
SendStatusHandler callback) override EXCLUDES(_mutex);
void
Tick() override;
void
QueueRemoveEmptyPath(const PathID_t &pathid) override;
util::StatusObject
ExtractStatus() const override;
void
Init(ILinkManager *linkManager, std::shared_ptr< Logic > logic);
private:
using Message = std::pair< std::vector< byte_t >, SendStatusHandler >;
struct MessageQueueEntry
{
uint16_t priority;
Message message;
PathID_t pathid;
RouterID router;
bool
operator<(const MessageQueueEntry &other) const
{
return other.priority < priority;
}
};
struct MessageQueueStats
{
uint64_t queued = 0;
uint64_t dropped = 0;
uint64_t sent = 0;
uint32_t queueWatermark = 0;
uint32_t perTickMax = 0;
uint32_t numTicks = 0;
};
using MessageQueue = std::priority_queue< MessageQueueEntry >;
void
OnSessionEstablished(const RouterID &router);
void
OnConnectTimeout(const RouterID &router);
void
OnRouterNotFound(const RouterID &router);
void
OnInvalidRouter(const RouterID &router);
void
OnNoLink(const RouterID &router);
void
OnSessionResult(const RouterID &router, const SessionResult result);
void
DoCallback(SendStatusHandler callback, SendStatus status);
void
QueueSessionCreation(const RouterID &remote);
bool
EncodeBuffer(const ILinkMessage *msg, llarp_buffer_t &buf);
bool
Send(const RouterID &remote, const Message &msg);
bool
SendIfSession(const RouterID &remote, const Message &msg);
bool
QueueOutboundMessage(const RouterID &remote, Message &&msg,
const PathID_t &pathid, uint16_t priority = 0);
void
ProcessOutboundQueue();
void
RemoveEmptyPathQueues();
void
SendRoundRobin();
void
FinalizeSessionRequest(const RouterID &router, SendStatus status)
EXCLUDES(_mutex);
llarp::thread::Queue< MessageQueueEntry > outboundQueue;
llarp::thread::Queue< PathID_t > removedPaths;
bool removedSomePaths;
mutable util::Mutex _mutex; // protects pendingSessionMessageQueues
std::unordered_map< RouterID, MessageQueue, RouterID::Hash >
pendingSessionMessageQueues GUARDED_BY(_mutex);
std::unordered_map< PathID_t, MessageQueue, PathID_t::Hash >
outboundMessageQueues;
std::queue< PathID_t > roundRobinOrder;
ILinkManager *_linkManager;
std::shared_ptr< Logic > _logic;
util::ContentionKiller m_Killer;
// paths cannot have pathid "0", so it can be used as the "pathid"
// for non-traffic (control) messages, so they can be prioritized.
static const PathID_t zeroID;
MessageQueueStats m_queueStats;
};
} // namespace llarp
#endif // LLARP_ROUTER_OUTBOUND_MESSAGE_HANDLER_HPP