Redo wire protocol race condition fix.

In commit a76acd4956 we attempted to fix
issues on service nodes that related to spamming service nodes with
traffc, but this caused a regression where clients could not connect
to the network.

However, we also did something idiotic with the protocol handshake.
The handshake logic was modified and caused client connections to
fail. This was due to a change in how we decided what a timed out
session is. We redo the close bug and revert the change to the
protocol handshake.

(cherry picked from commit b0b6e2b198)

llarp/iwp/session.cpp

@@ -144,6 +144,8 @@ namespace llarp
     void
     Session::EncryptAndSend(ILinkSession::Packet_t data)
     {
+      if (m_State == State::Closed)
+        return;
       m_EncryptNext.emplace_back(std::move(data));
       TriggerPump();
       if (!IsEstablished())
@@ -179,12 +181,9 @@ namespace llarp
         return;
       auto close_msg = CreatePacket(Command::eCLOS, 0, 16, 16);
       m_Parent->UnmapAddr(m_RemoteAddr);
-      m_State = State::Closed;
-      if (m_SentClosed.test_and_set())
-        return;
       EncryptAndSend(std::move(close_msg));
-
       LogInfo(m_Parent->PrintableName(), " closing connection to ", m_RemoteAddr);
+      m_State = State::Closed;
     }
 
     bool
@@ -355,7 +354,7 @@ namespace llarp
     bool
     Session::TimedOut(llarp_time_t now) const
     {
-      if (m_State == State::Ready)
+      if (m_State == State::Ready || m_State == State::LinkIntro)
       {
         return now > m_LastRX
             && now - m_LastRX

llarp/iwp/session.hpp

@@ -206,7 +206,6 @@ namespace llarp
 
       std::atomic_flag m_PlaintextEmpty;
       llarp::thread::Queue<CryptoQueue_t> m_PlaintextRecv;
-      std::atomic_flag m_SentClosed;
 
       void
       EncryptWorker(CryptoQueue_t msgs);

llarp/router/router.cpp

@@ -482,8 +482,8 @@ namespace llarp
       LogError("RC is invalid, not saving");
       return false;
     }
-    if (m_isServiceNode)
-      _nodedb->Put(_rc);
+    if (IsServiceNode())
+      _nodedb->Put(rc());
     QueueDiskIO([&]() { HandleSaveRC(); });
     return true;
   }