lokinet/llarp/iwp/linklayer.cpp
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

102 lines
2.6 KiB
C++

#include <iwp/linklayer.hpp>
#include <iwp/session.hpp>
#include <config/key_manager.hpp>
#include <memory>
#include <unordered_set>
namespace llarp
{
namespace iwp
{
LinkLayer::LinkLayer(std::shared_ptr< KeyManager > keyManager,
GetRCFunc getrc, LinkMessageHandler h,
SignBufferFunc sign, SessionEstablishedHandler est,
SessionRenegotiateHandler reneg,
TimeoutHandler timeout, SessionClosedHandler closed,
PumpDoneHandler pumpDone, bool allowInbound)
: ILinkLayer(keyManager, getrc, h, sign, est, reneg, timeout, closed,
pumpDone)
, permitInbound{allowInbound}
{
}
LinkLayer::~LinkLayer() = default;
const char*
LinkLayer::Name() const
{
return "iwp";
}
uint16_t
LinkLayer::Rank() const
{
return 2;
}
void
LinkLayer::QueueWork(std::function< void(void) > func)
{
m_Worker->addJob(func);
}
void
LinkLayer::RecvFrom(const Addr& from, ILinkSession::Packet_t pkt)
{
std::shared_ptr< ILinkSession > session;
auto itr = m_AuthedAddrs.find(from);
bool isNewSession = false;
if(itr == m_AuthedAddrs.end())
{
Lock_t lock(m_PendingMutex);
if(m_Pending.count(from) == 0)
{
if(not permitInbound)
return;
isNewSession = true;
m_Pending.insert({from, std::make_shared< Session >(this, from)});
}
session = m_Pending.find(from)->second;
}
else
{
Lock_t lock(m_AuthedLinksMutex);
auto range = m_AuthedLinks.equal_range(itr->second);
session = range.first->second;
}
if(session)
{
bool success = session->Recv_LL(std::move(pkt));
if(!success and isNewSession)
{
LogWarn(
"Brand new session failed; removing from pending sessions list");
m_Pending.erase(m_Pending.find(from));
}
}
}
bool
LinkLayer::MapAddr(const RouterID& r, ILinkSession* s)
{
if(!ILinkLayer::MapAddr(r, s))
return false;
m_AuthedAddrs.emplace(s->GetRemoteEndpoint(), r);
return true;
}
void
LinkLayer::UnmapAddr(const Addr& a)
{
m_AuthedAddrs.erase(a);
}
std::shared_ptr< ILinkSession >
LinkLayer::NewOutboundSession(const RouterContact& rc,
const AddressInfo& ai)
{
return std::make_shared< Session >(this, rc, ai);
}
} // namespace iwp
} // namespace llarp