propagate link layer message priority to link layer so it can order retransmissions with that in mind

llarp/iwp/message_buffer.cpp

@@ -10,12 +10,14 @@ namespace llarp
         uint64_t msgid,
         ILinkSession::Message_t msg,
         llarp_time_t now,
-        ILinkSession::CompletionHandler handler)
+        ILinkSession::CompletionHandler handler,
+        uint16_t priority)
         : m_Data{std::move(msg)}
         , m_MsgID{msgid}
         , m_Completed{handler}
         , m_LastFlush{now}
         , m_StartedAt{now}
+        , m_ResendPriority{priority}
     {
       const llarp_buffer_t buf(m_Data);
       CryptoManager::instance()->shorthash(m_Digest, buf);

llarp/iwp/message_buffer.hpp

@@ -40,7 +40,8 @@ namespace llarp
           uint64_t msgid,
           ILinkSession::Message_t data,
           llarp_time_t now,
-          ILinkSession::CompletionHandler handler);
+          ILinkSession::CompletionHandler handler,
+          uint16_t priority);
 
       ILinkSession::Message_t m_Data;
       uint64_t m_MsgID = 0;
@@ -49,6 +50,15 @@ namespace llarp
       llarp_time_t m_LastFlush = 0s;
       ShortHash m_Digest;
       llarp_time_t m_StartedAt = 0s;
+      uint16_t m_ResendPriority;
+
+      bool
+      operator<(const OutboundMessage& msg) const
+      {
+        // yes, the first order is reversed as higher means more important
+        // second part is for queue order
+        return msg.m_ResendPriority < m_ResendPriority or m_MsgID < msg.m_MsgID;
+      }
 
       ILinkSession::Packet_t
       XMIT() const;

llarp/iwp/session.cpp

@@ -5,6 +5,8 @@
 #include <llarp/util/meta/memfn.hpp>
 #include <llarp/router/abstractrouter.hpp>
 
+#include <queue>
+
 namespace llarp
 {
   namespace iwp
@@ -127,7 +129,7 @@ namespace llarp
       {
         LogError("failed to encode LIM for ", m_RemoteAddr);
       }
-      if (!SendMessageBuffer(std::move(data), h))
+      if (not SendMessageBuffer(std::move(data), h))
       {
         LogError("failed to send LIM to ", m_RemoteAddr);
       }
@@ -183,7 +185,7 @@ namespace llarp
 
     bool
     Session::SendMessageBuffer(
-        ILinkSession::Message_t buf, ILinkSession::CompletionHandler completed)
+        ILinkSession::Message_t buf, ILinkSession::CompletionHandler completed, uint16_t priority)
     {
       if (m_TXMsgs.size() >= MaxSendQueueSize)
       {
@@ -194,8 +196,9 @@ namespace llarp
       const auto now = m_Parent->Now();
       const auto msgid = m_TXID++;
       const auto bufsz = buf.size();
-      auto& msg = m_TXMsgs.emplace(msgid, OutboundMessage{msgid, std::move(buf), now, completed})
-                      .first->second;
+      auto& msg =
+          m_TXMsgs.emplace(msgid, OutboundMessage{msgid, std::move(buf), now, completed, priority})
+              .first->second;
       TriggerPump();
       EncryptAndSend(msg.XMIT());
       if (bufsz > FragmentSize)
@@ -253,15 +256,22 @@ namespace llarp
             msg.SendACKS(util::memFn(&Session::EncryptAndSend, this), now);
           }
         }
+        std::priority_queue<
+            OutboundMessage*,
+            std::vector<OutboundMessage*>,
+            ComparePtr<OutboundMessage*>>
+            resend;
         for (auto& [id, msg] : m_TXMsgs)
         {
           if (msg.ShouldFlush(now))
-          {
-            msg.FlushUnAcked(util::memFn(&Session::EncryptAndSend, this), now);
-          }
+            resend.push(&msg);
+        }
+        if (not resend.empty())
+        {
+          for (auto& msg = resend.top(); not resend.empty(); resend.pop())
+            msg->FlushUnAcked(util::memFn(&Session::EncryptAndSend, this), now);
         }
       }
-      assert(shared_from_this().use_count() > 1);
       if (not m_EncryptNext.empty())
       {
         m_Parent->QueueWork(

llarp/iwp/session.hpp

@@ -60,7 +60,10 @@ namespace llarp
       Tick(llarp_time_t now) override;
 
       bool
-      SendMessageBuffer(ILinkSession::Message_t msg, CompletionHandler resultHandler) override;
+      SendMessageBuffer(
+          ILinkSession::Message_t msg,
+          CompletionHandler resultHandler,
+          uint16_t priority = 0) override;
 
       void
       Send_LL(const byte_t* buf, size_t sz);

llarp/link/i_link_manager.hpp

@@ -30,7 +30,8 @@ namespace llarp
     SendTo(
         const RouterID& remote,
         const llarp_buffer_t& buf,
-        ILinkSession::CompletionHandler completed) = 0;
+        ILinkSession::CompletionHandler completed,
+        uint16_t priority = 0) = 0;
 
     virtual bool
     HasSessionTo(const RouterID& remote) const = 0;

llarp/link/link_manager.cpp

@@ -19,7 +19,7 @@ namespace llarp
       // TODO: may want to add some memory of session failures for a given
       //      router on a given link and not return that link here for a
       //      duration
-      if (!link->IsCompatable(rc))
+      if (not link->IsCompatable(rc))
         continue;
 
       return link;
@@ -36,7 +36,10 @@ namespace llarp
 
   bool
   LinkManager::SendTo(
-      const RouterID& remote, const llarp_buffer_t& buf, ILinkSession::CompletionHandler completed)
+      const RouterID& remote,
+      const llarp_buffer_t& buf,
+      ILinkSession::CompletionHandler completed,
+      uint16_t priority)
   {
     if (stopping)
       return false;
@@ -51,7 +54,7 @@ namespace llarp
       return false;
     }
 
-    return link->SendTo(remote, buf, completed);
+    return link->SendTo(remote, buf, completed, priority);
   }
 
   bool

llarp/link/link_manager.hpp

@@ -28,7 +28,8 @@ namespace llarp
     SendTo(
         const RouterID& remote,
         const llarp_buffer_t& buf,
-        ILinkSession::CompletionHandler completed) override;
+        ILinkSession::CompletionHandler completed,
+        uint16_t priority) override;
 
     bool
     HasSessionTo(const RouterID& remote) const override;

llarp/link/server.cpp

@@ -440,7 +440,10 @@ namespace llarp
 
   bool
   ILinkLayer::SendTo(
-      const RouterID& remote, const llarp_buffer_t& buf, ILinkSession::CompletionHandler completed)
+      const RouterID& remote,
+      const llarp_buffer_t& buf,
+      ILinkSession::CompletionHandler completed,
+      uint16_t priority)
   {
     std::shared_ptr<ILinkSession> s;
     {
@@ -459,7 +462,7 @@ namespace llarp
     }
     ILinkSession::Message_t pkt(buf.sz);
     std::copy_n(buf.base, buf.sz, pkt.begin());
-    return s && s->SendMessageBuffer(std::move(pkt), completed);
+    return s && s->SendMessageBuffer(std::move(pkt), completed, priority);
   }
 
   bool

llarp/link/server.hpp

@@ -148,7 +148,8 @@ namespace llarp
     SendTo(
         const RouterID& remote,
         const llarp_buffer_t& buf,
-        ILinkSession::CompletionHandler completed);
+        ILinkSession::CompletionHandler completed,
+        uint16_t priority);
 
     virtual bool
     GetOurAddressInfo(AddressInfo& addr) const;

llarp/link/session.hpp

@@ -57,7 +57,7 @@ namespace llarp
 
     /// send a message buffer to the remote endpoint
     virtual bool
-    SendMessageBuffer(Message_t, CompletionHandler handler) = 0;
+    SendMessageBuffer(Message_t, CompletionHandler handler, uint16_t priority) = 0;
 
     /// start the connection
     virtual void

llarp/router/outbound_message_handler.cpp

@@ -30,25 +30,28 @@ namespace llarp
       DoCallback(callback, SendStatus::InvalidRouter);
       return true;
     }
-    const uint16_t priority = msg.Priority();
+    MessageQueueEntry ent;
+    ent.router = remote;
+    ent.inform = std::move(callback);
+    ent.pathid = msg.pathid;
+    ent.priority = msg.Priority();
+
     std::array<byte_t, MAX_LINK_MSG_SIZE> linkmsg_buffer;
-    llarp_buffer_t buf(linkmsg_buffer);
+    llarp_buffer_t buf{linkmsg_buffer};
 
     if (!EncodeBuffer(msg, buf))
     {
       return false;
     }
 
-    Message message;
-    message.first.resize(buf.sz);
-    message.second = callback;
+    ent.message.resize(buf.sz);
 
-    std::copy_n(buf.base, buf.sz, message.first.data());
+    std::copy_n(buf.base, buf.sz, ent.message.data());
 
     // if we have a session to the destination, queue the message and return
     if (_router->linkManager().HasSessionTo(remote))
     {
-      QueueOutboundMessage(remote, std::move(message), msg.pathid, priority);
+      QueueOutboundMessage(std::move(ent));
       return true;
     }
 
@@ -58,16 +61,11 @@ namespace llarp
     // in progress.
     bool shouldCreateSession = false;
     {
-      util::Lock l(_mutex);
+      util::Lock l{_mutex};
 
       // create queue for <remote> if it doesn't exist, and get iterator
       auto [queue_itr, is_new] = pendingSessionMessageQueues.emplace(remote, MessageQueue());
-
-      MessageQueueEntry entry;
-      entry.priority = priority;
-      entry.message = message;
-      entry.router = remote;
-      queue_itr->second.push(std::move(entry));
+      queue_itr->second.push(std::move(ent));
 
       shouldCreateSession = is_new;
     }
@@ -86,7 +84,7 @@ namespace llarp
     m_Killer.TryAccess([this]() {
       recentlyRemovedPaths.Decay();
       ProcessOutboundQueue();
-      if (/*bool more = */ SendRoundRobin())
+      if (SendRoundRobin())
         _router->TriggerPump();
     });
   }
@@ -190,52 +188,48 @@ namespace llarp
   }
 
   bool
-  OutboundMessageHandler::Send(const RouterID& remote, const Message& msg)
+  OutboundMessageHandler::Send(const MessageQueueEntry& ent)
   {
-    const llarp_buffer_t buf(msg.first);
-    auto callback = msg.second;
+    const llarp_buffer_t buf{ent.message};
     m_queueStats.sent++;
-    return _router->linkManager().SendTo(remote, buf, [=](ILinkSession::DeliveryStatus status) {
-      if (status == ILinkSession::DeliveryStatus::eDeliverySuccess)
-        DoCallback(callback, SendStatus::Success);
-      else
-      {
-        DoCallback(callback, SendStatus::Congestion);
-      }
-    });
+    SendStatusHandler callback = ent.inform;
+    return _router->linkManager().SendTo(
+        ent.router,
+        buf,
+        [this, callback](ILinkSession::DeliveryStatus status) {
+          if (status == ILinkSession::DeliveryStatus::eDeliverySuccess)
+            DoCallback(callback, SendStatus::Success);
+          else
+          {
+            DoCallback(callback, SendStatus::Congestion);
+          }
+        },
+        ent.priority);
   }
 
   bool
-  OutboundMessageHandler::SendIfSession(const RouterID& remote, const Message& msg)
+  OutboundMessageHandler::SendIfSession(const MessageQueueEntry& ent)
   {
-    if (_router->linkManager().HasSessionTo(remote))
+    if (_router->linkManager().HasSessionTo(ent.router))
     {
-      return Send(remote, msg);
+      return Send(ent);
     }
     return false;
   }
 
   bool
-  OutboundMessageHandler::QueueOutboundMessage(
-      const RouterID& remote, Message&& msg, const PathID_t& pathid, uint16_t priority)
+  OutboundMessageHandler::QueueOutboundMessage(MessageQueueEntry entry)
   {
-    MessageQueueEntry entry;
-    entry.message = std::move(msg);
-
     // copy callback in case we need to call it, so we can std::move(entry)
-    auto callback_copy = entry.message.second;
-    entry.router = remote;
-    entry.pathid = pathid;
-    entry.priority = priority;
+    auto callback = entry.inform;
     if (outboundQueue.tryPushBack(std::move(entry)) != llarp::thread::QueueReturn::Success)
     {
       m_queueStats.dropped++;
-      DoCallback(callback_copy, SendStatus::Congestion);
+      DoCallback(callback, SendStatus::Congestion);
     }
     else
     {
       m_queueStats.queued++;
-
       uint32_t queueSize = outboundQueue.size();
       m_queueStats.queueWatermark = std::max(queueSize, m_queueStats.queueWatermark);
     }
@@ -272,7 +266,7 @@ namespace llarp
       }
       else
       {
-        DoCallback(entry.message.second, SendStatus::Congestion);
+        DoCallback(entry.inform, SendStatus::Congestion);
         m_queueStats.dropped++;
       }
     }
@@ -288,7 +282,7 @@ namespace llarp
     while (not routing_mq.empty())
     {
       const MessageQueueEntry& entry = routing_mq.top();
-      Send(entry.router, entry.message);
+      Send(entry);
       routing_mq.pop();
     }
 
@@ -331,7 +325,7 @@ namespace llarp
       {
         const MessageQueueEntry& entry = message_queue.top();
 
-        Send(entry.router, entry.message);
+        Send(entry);
         message_queue.pop();
 
         consecutive_empty = 0;
@@ -380,11 +374,11 @@ namespace llarp
 
       if (status == SendStatus::Success)
       {
-        Send(entry.router, entry.message);
+        Send(entry);
       }
       else
       {
-        DoCallback(entry.message.second, status);
+        DoCallback(entry.inform, status);
       }
       movedMessages.pop();
     }

llarp/router/outbound_message_handler.hpp

@@ -74,15 +74,14 @@ namespace llarp
     Init(AbstractRouter* router);
 
    private:
-    using Message = std::pair<std::vector<byte_t>, SendStatusHandler>;
-
     /* A message that has been queued for sending, but not yet
      * processed into an individual path's message queue.
      */
     struct MessageQueueEntry
     {
       uint16_t priority;
-      Message message;
+      std::vector<byte_t> message;
+      SendStatusHandler inform;
       PathID_t pathid;
       RouterID router;
 
@@ -131,14 +130,14 @@ namespace llarp
      * returns the result of the call to LinkManager::SendTo()
      */
     bool
-    Send(const RouterID& remote, const Message& msg);
+    Send(const MessageQueueEntry& ent);
 
     /* Sends the message along to the link layer if we have a session to the remote
      *
      * returns the result of the Send() call, or false if no session.
      */
     bool
-    SendIfSession(const RouterID& remote, const Message& msg);
+    SendIfSession(const MessageQueueEntry& ent);
 
     /* queues a message to the shared outbound message queue.
      *
@@ -149,8 +148,7 @@ namespace llarp
      * are placed in their paths' respective individual queues.
      */
     bool
-    QueueOutboundMessage(
-        const RouterID& remote, Message&& msg, const PathID_t& pathid, uint16_t priority = 0);
+    QueueOutboundMessage(MessageQueueEntry entry);
 
     /* Processes messages on the shared message queue into their paths' respective
      * individual queues.

llarp/router/rc_gossiper.cpp

@@ -116,7 +116,7 @@ namespace llarp
       m_router->NotifyRouterEvent<tooling::RCGossipSentEvent>(m_router->pubkey(), rc);
 
       // send message
-      peerSession->SendMessageBuffer(std::move(msg), nullptr);
+      peerSession->SendMessageBuffer(std::move(msg), nullptr, gossip.Priority());
     });
     return true;
   }