timers: Use signed for id, add UNUSED_ID

Author: fwsGonzo

api/kernel/timers.hpp

@@ -7,9 +7,9 @@
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -28,28 +28,30 @@
 class Timers
 {
 public:
-  using id_t       = uint32_t;
+  using id_t       = int32_t;
   using duration_t = std::chrono::microseconds;
   using handler_t  = delegate<void(id_t)>;
-  
+
+  static constexpr id_t UNUSED_ID = -1;
+
   /// create a one-shot timer that triggers @when from now
   /// returns a timer id
   static id_t oneshot(duration_t when, const handler_t&);
   /// create a periodic timer that begins @when and repeats every @period
   static id_t periodic(duration_t when, duration_t period, const handler_t&);
   // un-schedule timer, and free it
   static void stop(id_t);
-  
+
   /// returns the number of current, active timers
   static size_t active();
-  
+
   /// initialization
   typedef delegate<void(duration_t)> start_func_t;
   typedef delegate<void()> stop_func_t;
   static void init(const start_func_t&, const stop_func_t&);
   /// signal from the underlying hardware that it is calibrated and ready to go
   static void ready();
-  
+
   /// handler that processes timer interrupts
   static void timers_handler();
 };

api/net/tcp/connection.hpp

@@ -887,7 +887,7 @@ class Connection : public std::enable_shared_from_this<Connection> {
   /*
     When retransmission times out.
   */
-  void rtx_timeout(uint32_t);
+  void rtx_timeout(int);
 
 
   /** Start the timewait timeout for 2*MSL */
@@ -900,7 +900,7 @@ class Connection : public std::enable_shared_from_this<Connection> {
   void timewait_restart();
 
   /** When timewait timer times out */
-  void timewait_timeout(uint32_t);
+  void timewait_timeout(int);
 
   /*
     Tell the host (TCP) to delete this connection.

src/net/tcp/connection.cpp

@@ -737,7 +737,7 @@ void Connection::rtx_clear() {
        MUST be re-initialized to 3 seconds when data transmission
        begins (i.e., after the three-way handshake completes).
 */
-void Connection::rtx_timeout(uint32_t) {
+void Connection::rtx_timeout(Timers::id_t) {
   rtx_timer.active = false;
   debug("<TCP::Connection::RTX@timeout> %s Timed out (%f). FS: %u\n",
     to_string().c_str(), flight_size());
@@ -833,7 +833,7 @@ void Connection::timewait_restart() {
   timewait_start();
 }
 
-void Connection::timewait_timeout(uint32_t) {
+void Connection::timewait_timeout(Timers::id_t) {
   debug("<Connection> TimeWait timed out, closing.\n");
   timewait_timer.active = false;