Merged from silc_1_0_branch.
[silc.git] / lib / silcutil / silcschedule.c
index ee1063d42917b329bfe4306bcea7cd6b0ee7e3bd..e0f658b08f52807e42fa93107a14f107155bbf59 100644 (file)
@@ -1,16 +1,15 @@
 /*
 
-  silcschedule.c
+  silcschedule.c 
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 1998 - 2001 Pekka Riikonen
+  Copyright (C) 1998 - 2002 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
-  the Free Software Foundation; either version 2 of the License, or
-  (at your option) any later version.
-  
+  the Free Software Foundation; version 2 of the License.
+
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 /* $Id$ */
 
 #include "silcincludes.h"
+#include "silcschedule_i.h"
 
-/* Routine to remove the task. Implemented in silctask.c. */
-int silc_task_remove(SilcTaskQueue queue, SilcTask task);
+/* Forward declarations */
+typedef struct SilcTaskQueueStruct *SilcTaskQueue;
 
-/* System specific routines. Implemented under unix/ and win32/. */
+/* System specific routines. Implemented under unix/, win32/ and such. */
 
-/* System specific select(). */
-int silc_select(int n, fd_set *readfds, fd_set *writefds,
-               fd_set *exceptfds, struct timeval *timeout);
+/* System specific select(). Returns same values as normal select(). */
+int silc_select(SilcScheduleFd fds, SilcUInt32 fds_count, 
+               struct timeval *timeout);
 
-/* Initializes the wakeup of the scheduler. In multi-threaded environment
+/* Initializes the platform specific scheduler.  This for example initializes
+   the wakeup mechanism of the scheduler.  In multi-threaded environment
    the scheduler needs to be wakenup when tasks are added or removed from
-   the task queues. This will initialize the wakeup for the scheduler.
-   Any tasks that needs to be registered must be registered to the `queue'.
-   It is guaranteed that the scheduler will automatically free any
-   registered tasks in this queue. This is system specific routine. */
-void *silc_schedule_wakeup_init(void *queue);
+   the task queues.  Returns context to the platform specific scheduler. */
+void *silc_schedule_internal_init(SilcSchedule schedule, void *context);
 
-/* Uninitializes the system specific wakeup. */
-void silc_schedule_wakeup_uninit(void *context);
+/* Uninitializes the platform specific scheduler context. */
+void silc_schedule_internal_uninit(void *context);
 
 /* Wakes up the scheduler. This is platform specific routine */
-void silc_schedule_wakeup_internal(void *context);
-
-/* Structure holding list of file descriptors, scheduler is supposed to
-   be listenning. The max_fd field is the maximum number of possible file
-   descriptors in the list. This value is set at the initialization
-   of the scheduler and it usually is the maximum number of connections 
-   allowed. */
-typedef struct {
-  int *fd;
-  uint32 last_fd;
-  uint32 max_fd;
-} SilcScheduleFdList;
+void silc_schedule_internal_wakeup(void *context);
+
+/* Register signal */
+void silc_schedule_internal_signal_register(void *context,
+                                            SilcUInt32 signal,
+                                            SilcTaskCallback callback,
+                                            void *callback_context);
+
+/* Unregister signal */
+void silc_schedule_internal_signal_unregister(void *context,
+                                              SilcUInt32 signal,
+                                              SilcTaskCallback callback,
+                                              void *callback_context);
+
+/* Mark signal to be called later. */
+void silc_schedule_internal_signal_call(void *context, SilcUInt32 signal);
+
+/* Call all signals */
+void silc_schedule_internal_signals_call(void *context,
+                                        SilcSchedule schedule);
+
+/* Block registered signals in scheduler. */
+void silc_schedule_internal_signals_block(void *context);
+
+/* Unblock registered signals in schedule. */
+void silc_schedule_internal_signals_unblock(void *context);
+
+/* Internal task management routines. */
+
+static void silc_schedule_dispatch_timeout(SilcSchedule schedule,
+                                          bool dispatch_all);
+static void silc_task_queue_alloc(SilcTaskQueue *queue);
+static void silc_task_queue_free(SilcTaskQueue queue);
+static SilcTask silc_task_find(SilcTaskQueue queue, SilcUInt32 fd);
+static SilcTask silc_task_add(SilcTaskQueue queue, SilcTask newtask, 
+                             SilcTaskPriority priority);
+static SilcTask silc_task_get_first(SilcTaskQueue queue, SilcTask first);
+static SilcTask silc_task_add_timeout(SilcTaskQueue queue, SilcTask newtask,
+                                     SilcTaskPriority priority);
+static int silc_schedule_task_remove(SilcTaskQueue queue, SilcTask task);
+static void silc_task_del_by_context(SilcTaskQueue queue, void *context);
+static void silc_task_del_by_callback(SilcTaskQueue queue,
+                                     SilcTaskCallback callback);
+static void silc_task_del_by_fd(SilcTaskQueue queue, SilcUInt32 fd);
+
+/* Returns the task queue by task type */
+#define SILC_SCHEDULE_GET_QUEUE(type)                          \
+  (type == SILC_TASK_FD ? schedule->fd_queue :                 \
+   type == SILC_TASK_TIMEOUT ? schedule->timeout_queue :       \
+   schedule->generic_queue)
+
+/* Locks. These also blocks signals that we care about and thus guarantee
+   that while we are in scheduler no signals can happen.  This way we can
+   synchronise signals with SILC Scheduler. */
+#define SILC_SCHEDULE_LOCK(schedule)                           \
+do {                                                           \
+  silc_schedule_internal_signals_block(schedule->internal);    \
+  silc_mutex_lock(schedule->lock);                             \
+} while (0)
+#define SILC_SCHEDULE_UNLOCK(schedule)                         \
+do {                                                           \
+  silc_mutex_unlock(schedule->lock);                           \
+  silc_schedule_internal_signals_unblock(schedule->internal);  \
+} while (0)
+
+/* SILC Task object. Represents one task in the scheduler. */
+struct SilcTaskStruct {
+  SilcUInt32 fd;
+  SilcTaskCallback callback;      /* Task callback */
+  void *context;                  /* Task callback context */
+  struct timeval timeout;         /* Set for timeout tasks */
+  unsigned int valid : 1;         /* Set when task is valid */
+  unsigned int priority : 2;      /* Priority of the task */
+  unsigned int type : 5;           /* Type of the task */
+
+  /* Pointers forming doubly linked circular list */
+  struct SilcTaskStruct *next;
+  struct SilcTaskStruct *prev;
+};
+
+/* SILC Task Queue object. The queue holds all the tasks in the scheduler.
+   There are always three task queues in the scheduler. One for non-timeout
+   tasks (fd tasks performing tasks over specified file descriptor), 
+   one for timeout tasks and one for generic tasks. */
+struct SilcTaskQueueStruct {
+  SilcTask task;               /* Pointer to all tasks */
+  struct timeval timeout;      /* Current timeout */
+  SILC_MUTEX_DEFINE(lock);     /* Queue's lock */
+};
 
 /* 
    SILC Scheduler structure.
@@ -87,17 +162,24 @@ typedef struct {
        to those that have specificly registered a non-timeout task. This hook
        is also initialized in silc_schedule_init function.
 
-   SilcScheduleFdList fd_list
+   SilcScheduleFd fd_list
 
        List of file descriptors the scheduler is supposed to be listenning.
        This is updated internally.
 
+   SilcUInt32 max_fd
+   SilcUInt32 last_fd
+
+       Size of the fd_list list. There can be `max_fd' many tasks in
+       the scheduler at once. The `last_fd' is the last valid entry
+       in the fd_list.
+
    struct timeval *timeout;
 
        Pointer to the schedules next timeout. Value of this timeout is
        automatically updated in the silc_schedule function.
 
-   int valid
+   bool valid
 
        Marks validity of the scheduler. This is a boolean value. When this
        is false the scheduler is terminated and the program will end. This
@@ -110,83 +192,71 @@ typedef struct {
        File descriptor sets for select(). These are automatically managed
        by the scheduler and should not be touched otherwise.
 
-   int max_fd
+   void *internal
 
-       Number of maximum file descriptors for select(). This, as well, is
-       managed automatically by the scheduler and should be considered to 
-       be read-only field otherwise.
+       System specific scheduler context.
 
-   void *wakeup
+   SILC_MUTEX_DEFINE(lock)
+  
+       Scheduler lock.
+
+   bool signal_tasks
 
-       System specific wakeup context. On multi-threaded environments the
-       scheduler needs to be wakenup (in the thread) when tasks are added
-       or removed. This is initialized by silc_schedule_wakeup_init.
+       TRUE when tasks has been registered from signals.  Next round in
+       scheduler will call the callbacks when this is TRUE.
 
 */
 struct SilcScheduleStruct {
+  void *app_context;           /* Application specific context */
   SilcTaskQueue fd_queue;
   SilcTaskQueue timeout_queue;
   SilcTaskQueue generic_queue;
-  SilcScheduleFdList fd_list;
+  SilcScheduleFd fd_list;
+  SilcUInt32 max_fd;
+  SilcUInt32 last_fd;
   struct timeval *timeout;
   bool valid;
-  fd_set in;
-  fd_set out;
-  int max_fd;
-  void *wakeup;
+  void *internal;
   SILC_MUTEX_DEFINE(lock);
   bool is_locked;
+  bool signal_tasks;
 };
 
-/* Initializes the scheduler. Sets the non-timeout task queue hook and
-   the timeout task queue hook. This must be called before the scheduler
-   is able to work. This will allocate the queue pointers if they are
-   not allocated. Returns the scheduler context that must be freed by
-   the silc_schedule_uninit function. */
+/* Initializes the scheduler. This returns the scheduler context that
+   is given as arugment usually to all silc_schedule_* functions.
+   The `max_tasks' indicates the number of maximum tasks that the
+   scheduler can handle. The `app_context' is application specific
+   context that is delivered to task callbacks. */
 
-SilcSchedule silc_schedule_init(SilcTaskQueue *fd_queue,
-                               SilcTaskQueue *timeout_queue,
-                               SilcTaskQueue *generic_queue,
-                               int max_fd)
+SilcSchedule silc_schedule_init(int max_tasks, void *app_context)
 {
   SilcSchedule schedule;
-  int i;
 
   SILC_LOG_DEBUG(("Initializing scheduler"));
 
   schedule = silc_calloc(1, sizeof(*schedule));
 
-  /* Register the task queues if they are not registered already. In SILC
-     we have by default three task queues. One task queue for non-timeout
-     tasks which perform different kind of I/O on file descriptors, timeout
-     task queue for timeout tasks, and, generic non-timeout task queue whose
-     tasks apply to all connections. */
-  if (!*fd_queue)
-    silc_task_queue_alloc(schedule, fd_queue, TRUE);
-  if (!*timeout_queue)
-    silc_task_queue_alloc(schedule, timeout_queue, TRUE);
-  if (!*generic_queue)
-    silc_task_queue_alloc(schedule, generic_queue, TRUE);
+  /* Allocate three task queues, one for file descriptor based tasks,
+     one for timeout tasks and one for generic tasks. */
+  silc_task_queue_alloc(&schedule->fd_queue);
+  silc_task_queue_alloc(&schedule->timeout_queue);
+  silc_task_queue_alloc(&schedule->generic_queue);
+
+  if (!max_tasks)
+    max_tasks = 200;
 
   /* Initialize the scheduler */
-  schedule->fd_queue = *fd_queue;
-  schedule->timeout_queue = *timeout_queue;
-  schedule->generic_queue = *generic_queue;
-  schedule->fd_list.fd = silc_calloc(max_fd, sizeof(*schedule->fd_list.fd));
-  schedule->fd_list.last_fd = 0;
-  schedule->fd_list.max_fd = max_fd;
+  schedule->fd_list = silc_calloc(max_tasks, sizeof(*schedule->fd_list));
+  schedule->max_fd = max_tasks;
   schedule->timeout = NULL;
   schedule->valid = TRUE;
-  FD_ZERO(&schedule->in);
-  FD_ZERO(&schedule->out);
-  schedule->max_fd = -1;
-  for (i = 0; i < max_fd; i++)
-    schedule->fd_list.fd[i] = -1;
+  schedule->app_context = app_context;
 
+  /* Allocate scheduler lock */
   silc_mutex_alloc(&schedule->lock);
 
-  /* Initialize the wakeup */
-  schedule->wakeup = silc_schedule_wakeup_init(schedule->fd_queue);
+  /* Initialize the platform specific scheduler. */
+  schedule->internal = silc_schedule_internal_init(schedule, app_context);
 
   return schedule;
 }
@@ -198,42 +268,59 @@ SilcSchedule silc_schedule_init(SilcTaskQueue *fd_queue,
 
 bool silc_schedule_uninit(SilcSchedule schedule)
 {
-
   SILC_LOG_DEBUG(("Uninitializing scheduler"));
 
   if (schedule->valid == TRUE)
     return FALSE;
 
+  /* Dispatch all timeouts before going away */
+  SILC_SCHEDULE_LOCK(schedule);
+  silc_mutex_lock(schedule->timeout_queue->lock);
+  silc_schedule_dispatch_timeout(schedule, TRUE);
+  silc_mutex_unlock(schedule->timeout_queue->lock);
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  /* Deliver signals before going away */
+  if (schedule->signal_tasks) {
+    silc_schedule_internal_signals_call(schedule->internal, schedule);
+    schedule->signal_tasks = FALSE;
+  }
+
   /* Unregister all tasks */
-  if (schedule->fd_queue)
-    silc_task_remove(schedule->fd_queue, SILC_ALL_TASKS);
-  if (schedule->timeout_queue)
-    silc_task_remove(schedule->timeout_queue, SILC_ALL_TASKS);
-  if (schedule->generic_queue)
-    silc_task_remove(schedule->generic_queue, SILC_ALL_TASKS);
+  silc_schedule_task_remove(schedule->fd_queue, SILC_ALL_TASKS);
+  silc_schedule_task_remove(schedule->timeout_queue, SILC_ALL_TASKS);
+  silc_schedule_task_remove(schedule->generic_queue, SILC_ALL_TASKS);
 
   /* Unregister all task queues */
-  if (schedule->fd_queue)
-    silc_task_queue_free(schedule->fd_queue);
-  if (schedule->timeout_queue)
-    silc_task_queue_free(schedule->timeout_queue);
-  if (schedule->generic_queue)
-    silc_task_queue_free(schedule->generic_queue);
-
-  /* Clear the fd list */
-  if (schedule->fd_list.fd) {
-    memset(schedule->fd_list.fd, -1, schedule->fd_list.max_fd);
-    silc_free(schedule->fd_list.fd);
-  }
+  silc_task_queue_free(schedule->fd_queue);
+  silc_task_queue_free(schedule->timeout_queue);
+  silc_task_queue_free(schedule->generic_queue);
+
+  silc_free(schedule->fd_list);
 
-  /* Uninit the wakeup */
-  silc_schedule_wakeup_uninit(schedule->wakeup);
+  /* Uninit the platform specific scheduler. */
+  silc_schedule_internal_uninit(schedule->internal);
 
   silc_mutex_free(schedule->lock);
+  silc_free(schedule);
 
   return TRUE;
 }
 
+/* Enlarge the capabilities of the scheduler to handle tasks to `max_tasks'. */
+
+bool silc_schedule_reinit(SilcSchedule schedule, int max_tasks)
+{
+  SILC_SCHEDULE_LOCK(schedule);
+  if (schedule->max_fd <= max_tasks)
+    return FALSE;
+  schedule->fd_list = silc_realloc(schedule->fd_list, 
+                                  (sizeof(*schedule->fd_list) * max_tasks));
+  schedule->max_fd = max_tasks;
+  SILC_SCHEDULE_UNLOCK(schedule);
+  return TRUE;
+}
+
 /* Stops the schedule even if it is not supposed to be stopped yet. 
    After calling this, one should call silc_schedule_uninit (after the 
    silc_schedule has returned). */
@@ -241,421 +328,304 @@ bool silc_schedule_uninit(SilcSchedule schedule)
 void silc_schedule_stop(SilcSchedule schedule)
 {
   SILC_LOG_DEBUG(("Stopping scheduler"));
-  silc_mutex_lock(schedule->lock);
+  SILC_SCHEDULE_LOCK(schedule);
   schedule->valid = FALSE;
-  silc_mutex_unlock(schedule->lock);
+  SILC_SCHEDULE_UNLOCK(schedule);
 }
 
-/* Sets a file descriptor to be listened by select() in scheduler. One can
-   call this directly if wanted. This can be called multiple times for
-   one file descriptor to set different iomasks. */
+/* Executes nontimeout tasks. It then checks whether any of ther fd tasks
+   was signaled by the silc_select. If some task was not signaled then
+   all generic tasks are executed for that task. The generic tasks are
+   never executed for task that has explicit fd task set. */
+/* This holds the schedule->lock and the queue locks. */
 
-void silc_schedule_set_listen_fd(SilcSchedule schedule, int fd, uint32 iomask)
+static void silc_schedule_dispatch_nontimeout(SilcSchedule schedule)
 {
-  silc_mutex_lock(schedule->lock);
+  SilcTask task;
+  int i;
+  SilcUInt32 fd, last_fd = schedule->last_fd;
 
-  schedule->fd_list.fd[fd] = iomask;
-  
-  if (fd > schedule->fd_list.last_fd)
-    schedule->fd_list.last_fd = fd;
+  for (i = 0; i <= last_fd; i++) {
+    if (schedule->fd_list[i].events == 0)
+      continue;
 
-  silc_mutex_unlock(schedule->lock);
+    fd = schedule->fd_list[i].fd;
+
+    /* First check whether this fd has task in the fd queue */
+    silc_mutex_lock(schedule->fd_queue->lock);
+    task = silc_task_find(schedule->fd_queue, fd);
+
+    /* If the task was found then execute its callbacks. If not then
+       execute all generic tasks for that fd. */
+    if (task) {
+      /* Validity of the task is checked always before and after
+        execution beacuse the task might have been unregistered
+        in the callback function, ie. it is not valid anymore. */
+
+      /* Is the task ready for reading */
+      if (task->valid && schedule->fd_list[i].revents & SILC_TASK_READ) {
+       silc_mutex_unlock(schedule->fd_queue->lock);
+       SILC_SCHEDULE_UNLOCK(schedule);
+       task->callback(schedule, schedule->app_context,
+                      SILC_TASK_READ, task->fd, task->context);
+       SILC_SCHEDULE_LOCK(schedule);
+       silc_mutex_lock(schedule->fd_queue->lock);
+      }
+
+      /* Is the task ready for writing */
+      if (task->valid && schedule->fd_list[i].revents & SILC_TASK_WRITE) {
+       silc_mutex_unlock(schedule->fd_queue->lock);
+       SILC_SCHEDULE_UNLOCK(schedule);
+       task->callback(schedule, schedule->app_context,
+                      SILC_TASK_WRITE, task->fd, task->context);
+       SILC_SCHEDULE_LOCK(schedule);
+       silc_mutex_lock(schedule->fd_queue->lock);
+      }
+
+      if (!task->valid)
+       silc_schedule_task_remove(schedule->fd_queue, task);
+
+      silc_mutex_unlock(schedule->fd_queue->lock);
+    } else {
+      /* Run generic tasks for this fd. */
+
+      silc_mutex_unlock(schedule->fd_queue->lock);
+
+      silc_mutex_lock(schedule->generic_queue->lock);
+      if (!schedule->generic_queue->task) {
+       silc_mutex_unlock(schedule->generic_queue->lock);
+       continue;
+      }
+
+      task = schedule->generic_queue->task;
+      while(1) {
+       /* Validity of the task is checked always before and after
+          execution beacuse the task might have been unregistered
+          in the callback function, ie. it is not valid anymore. */
+
+       /* Is the task ready for reading */                             
+       if (task->valid && schedule->fd_list[i].revents & SILC_TASK_READ) {
+         silc_mutex_unlock(schedule->generic_queue->lock);
+         SILC_SCHEDULE_UNLOCK(schedule);
+         task->callback(schedule, schedule->app_context,
+                        SILC_TASK_READ, fd, task->context);
+         SILC_SCHEDULE_LOCK(schedule);
+         silc_mutex_lock(schedule->generic_queue->lock);
+       }
+
+       /* Is the task ready for writing */                             
+       if (task->valid && schedule->fd_list[i].revents & SILC_TASK_WRITE) {
+         silc_mutex_unlock(schedule->generic_queue->lock);
+         SILC_SCHEDULE_UNLOCK(schedule);
+         task->callback(schedule, schedule->app_context,
+                        SILC_TASK_WRITE, fd, task->context);
+         SILC_SCHEDULE_LOCK(schedule);
+         silc_mutex_lock(schedule->generic_queue->lock);
+       }
+
+       if (!task->valid) {
+         /* Invalid (unregistered) tasks are removed from the
+            task queue. */
+         if (schedule->generic_queue->task == task->next) {
+           silc_schedule_task_remove(schedule->generic_queue, task);
+           silc_mutex_unlock(schedule->generic_queue->lock);
+           break;
+         }
+
+         task = task->next;
+         silc_schedule_task_remove(schedule->generic_queue, task);
+         continue;
+       }
+
+       /* Break if there isn't more tasks in the queue */
+       if (schedule->generic_queue->task == task->next)
+         break;
+
+       task = task->next;
+      }                        
+
+      silc_mutex_unlock(schedule->generic_queue->lock);
+    }
+  }
 }
 
-/* Removes a file descriptor from listen list. */
+/* Executes all tasks whose timeout has expired. The task is removed from
+   the task queue after the callback function has returned. Also, invalid
+   tasks are removed here. We don't have to care about priorities because 
+   tasks are already sorted in their priority order at the registration 
+   phase. */
+/* This holds the schedule->lock and the schedule->timeout_queue->lock */
 
-void silc_schedule_unset_listen_fd(SilcSchedule schedule, int fd)
+static void silc_schedule_dispatch_timeout(SilcSchedule schedule,
+                                          bool dispatch_all)
 {
-  silc_mutex_lock(schedule->lock);
+  SilcTaskQueue queue = schedule->timeout_queue;
+  SilcTask task;
+  struct timeval curtime;
 
-  schedule->fd_list.fd[fd] = -1;
-  
-  if (fd == schedule->fd_list.last_fd) {
-    int i;
+  SILC_LOG_DEBUG(("Running timeout tasks"));
+
+  silc_gettimeofday(&curtime);
+
+  queue = schedule->timeout_queue;
+  if (queue && queue->task) {
+    task = queue->task;
+
+    /* Walk thorugh all tasks in the particular task queue and run all 
+       the expired tasks. */
+    while(1) {
+      /* Execute the task if the timeout has expired */
+      if (dispatch_all ||
+         silc_compare_timeval(&task->timeout, &curtime)) {
+        if (task->valid) {
+         silc_mutex_unlock(queue->lock);
+         SILC_SCHEDULE_UNLOCK(schedule);
+         task->callback(schedule, schedule->app_context,
+                        SILC_TASK_EXPIRE, task->fd, task->context);
+         SILC_SCHEDULE_LOCK(schedule);
+         silc_mutex_lock(queue->lock);
+       }
+
+        /* Break if there isn't more tasks in the queue */
+       if (queue->task == task->next) {
+         silc_schedule_task_remove(queue, task);
+         break;
+        }
+
+        task = task->next;
+
+        /* Remove the task from queue */
+        silc_schedule_task_remove(queue, task->prev);
+      } else {
+        /* The timeout hasn't expired, check for next one */
+
+        /* Break if there isn't more tasks in the queue */
+        if (queue->task == task->next)
+          break;
+
+        task = task->next;
+      }
+    }
+  }
+}
 
-    for (i = fd; i >= 0; i--)
-      if (schedule->fd_list.fd[i] != -1)
-       break;
+/* Calculates next timeout for select(). This is the timeout value
+   when at earliest some of the timeout tasks expire. If this is in the
+   past, they will be run now. */
+/* This holds the schedule->lock and the schedule->timeout_queue->lock */
 
-    schedule->fd_list.last_fd = i < 0 ? 0 : i;
-  }
+static void silc_schedule_select_timeout(SilcSchedule schedule)
+{
+  SilcTaskQueue queue = schedule->timeout_queue;
+  SilcTask task;
+  struct timeval curtime;
 
-  silc_mutex_unlock(schedule->lock);
-}
+  /* Get the current time */
+  silc_gettimeofday(&curtime);
+  schedule->timeout = NULL;
 
-/* Executes tasks matching the file descriptor set by select(). The task
-   remains on the task queue after execution. Invalid tasks are removed 
-   here from the task queue. This macro is used by silc_schedule function. 
-   We don't have to care about the tasks priority here because the tasks
-   are sorted in their priority order already at the registration phase. */
-/* This must be called holding the schedule->lock and the
-   schedule->fd_queue->lock. */
-
-#define SILC_SCHEDULE_RUN_TASKS                                                   \
-do {                                                                      \
-  queue = schedule->fd_queue;                                             \
-  if (queue && queue->valid == TRUE && queue->task) {                     \
-    task = queue->task;                                                           \
-                                                                          \
-    /* Walk thorugh all tasks in the particular task queue and            \
-       execute the callback functions of those tasks matching the         \
-       fd set by select(). */                                             \
-    while(1) {                                                            \
-      /* Validity of the task is checked always before and after          \
-        execution beacuse the task might have been unregistered           \
-        in the callback function, ie. it is not valid anymore. */         \
-                                                                          \
-      if (task->valid) {                                                  \
-       /* Task ready for reading */                                       \
-       if ((FD_ISSET(task->fd, &schedule->in)) &&                         \
-           (task->iomask & (1L << SILC_TASK_READ))) {                     \
-          silc_mutex_unlock(queue->lock);                                 \
-          silc_mutex_unlock(schedule->lock);                              \
-         task->callback(queue, SILC_TASK_READ, task->context, task->fd);  \
-          silc_mutex_lock(schedule->lock);                                \
-          silc_mutex_lock(queue->lock);                                           \
-          is_run = TRUE;                                                  \
-       }                                                                  \
-      }                                                                           \
-                                                                          \
-      if (task->valid) {                                                  \
-       /* Task ready for writing */                                       \
-       if ((FD_ISSET(task->fd, &schedule->out)) &&                        \
-           (task->iomask & (1L << SILC_TASK_WRITE))) {                    \
-          silc_mutex_unlock(queue->lock);                                 \
-          silc_mutex_unlock(schedule->lock);                              \
-         task->callback(queue, SILC_TASK_WRITE, task->context, task->fd); \
-          silc_mutex_lock(schedule->lock);                                \
-          silc_mutex_lock(queue->lock);                                           \
-          is_run = TRUE;                                                  \
-       }                                                                  \
-      }                                                                           \
-                                                                          \
-      if (!task->valid) {                                                 \
-       /* Invalid (unregistered) tasks are removed from the               \
-          task queue. */                                                  \
-       if (queue->task == task->next) {                                   \
-         silc_task_remove(queue, task);                                   \
-          break;                                                          \
-        }                                                                 \
-                                                                          \
-        task = task->next;                                                \
-        silc_task_remove(queue, task->prev);                              \
-        continue;                                                         \
-      }                                                                           \
-                                                                          \
-      /* Break if there isn't more tasks in the queue */                  \
-      if (queue->task == task->next)                                      \
-        break;                                                            \
-                                                                          \
-      task = task->next;                                                  \
-    }                                                                     \
-  }                                                                       \
-} while(0)
-
-/* Selects tasks to be listened by select(). These are the non-timeout
-   tasks. This checks the scheduler's fd list. This macro is used by 
-   silc_schedule function. */
-/* This must be called holding schedule->lock. */
-
-#define SILC_SCHEDULE_SELECT_TASKS                             \
-do {                                                           \
-  for (i = 0; i <= schedule->fd_list.last_fd; i++) {           \
-    if (schedule->fd_list.fd[i] != -1) {                       \
-                                                               \
-      /* Set the max fd value for select() to listen */                \
-      if (i > schedule->max_fd)                                        \
-       schedule->max_fd = i;                                   \
-                                                               \
-      /* Add tasks for reading */                              \
-      if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_READ)))  \
-       FD_SET(i, &schedule->in);                               \
-                                                               \
-      /* Add tasks for writing */                              \
-      if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_WRITE))) \
-       FD_SET(i, &schedule->out);                              \
-    }                                                          \
-  }                                                            \
-} while(0)
+  /* First task in the task queue has always the smallest timeout. */
+  task = queue->task;
+  while(1) {
+    if (task && task->valid == TRUE) {
+      /* If the timeout is in past, we will run the task and all other
+        timeout tasks from the past. */
+      if (silc_compare_timeval(&task->timeout, &curtime)) {
+       silc_schedule_dispatch_timeout(schedule, FALSE);
+
+       /* The task(s) has expired and doesn't exist on the task queue
+          anymore. We continue with new timeout. */
+       queue = schedule->timeout_queue;
+       task = queue->task;
+       if (task == NULL || task->valid == FALSE)
+         break;
+      }
+
+      /* Calculate the next timeout for select() */
+      queue->timeout.tv_sec = task->timeout.tv_sec - curtime.tv_sec;
+      queue->timeout.tv_usec = task->timeout.tv_usec - curtime.tv_usec;
+      if (queue->timeout.tv_sec < 0)
+       queue->timeout.tv_sec = 0;
+
+      /* We wouldn't want to go under zero, check for it. */
+      if (queue->timeout.tv_usec < 0) {
+       queue->timeout.tv_sec -= 1;
+       if (queue->timeout.tv_sec < 0)
+         queue->timeout.tv_sec = 0;
+       queue->timeout.tv_usec += 1000000L;
+      }
+
+      /* We've got the timeout value */
+      break;
+    } else {
+      /* Task is not valid, remove it and try next one. */
+      silc_schedule_task_remove(queue, task);
+      task = queue->task;
+      if (queue->task == NULL)
+       break;
+    }
+  }
 
-/* Executes all tasks whose timeout has expired. The task is removed from
-   the task queue after the callback function has returned. Also, invalid
-   tasks are removed here. The current time must be get before calling this
-   macro. This macro is used by silc_schedule function. We don't have to
-   care about priorities because tasks are already sorted in their priority
-   order at the registration phase. */
-/* This must be called with holding the schedule->lock and the
-   schedule->timeout_queue->lock */
-
-#define SILC_SCHEDULE_RUN_TIMEOUT_TASKS                                        \
-do {                                                                   \
-  queue = schedule->timeout_queue;                                     \
-  if (queue && queue->valid == TRUE && queue->task) {                  \
-    task = queue->task;                                                        \
-                                                                       \
-    /* Walk thorugh all tasks in the particular task queue             \
-       and run all the expired tasks. */                               \
-    while(1) {                                                         \
-      /* Execute the task if the timeout has expired */                        \
-      if (silc_task_timeout_compare(&task->timeout, &curtime)) {       \
-                                                                       \
-        /* Task ready for reading */                                   \
-        if (task->valid) {                                             \
-          if ((task->iomask & (1L << SILC_TASK_READ))) {               \
-            silc_mutex_unlock(queue->lock);                            \
-            silc_mutex_unlock(schedule->lock);                         \
-           task->callback(queue, SILC_TASK_READ,                       \
-                          task->context, task->fd);                    \
-            silc_mutex_lock(schedule->lock);                           \
-            silc_mutex_lock(queue->lock);                              \
-          }                                                            \
-       }                                                               \
-                                                                       \
-        /* Task ready for writing */                                   \
-        if (task->valid) {                                             \
-          if ((task->iomask & (1L << SILC_TASK_WRITE))) {              \
-            silc_mutex_unlock(queue->lock);                            \
-            silc_mutex_unlock(schedule->lock);                         \
-           task->callback(queue, SILC_TASK_WRITE,                      \
-                          task->context, task->fd);                    \
-            silc_mutex_lock(schedule->lock);                           \
-            silc_mutex_lock(queue->lock);                              \
-          }                                                            \
-        }                                                              \
-                                                                       \
-        /* Break if there isn't more tasks in the queue */             \
-       if (queue->task == task->next) {                                \
-         /* Remove the task from queue */                              \
-         silc_task_remove(queue, task);                                \
-         break;                                                        \
-        }                                                              \
-                                                                       \
-        task = task->next;                                             \
-                                                                       \
-        /* Remove the task from queue */                               \
-        silc_task_remove(queue, task->prev);                           \
-      } else {                                                         \
-        /* The timeout hasn't expired, check for next one */           \
-                                                                       \
-        /* Break if there isn't more tasks in the queue */             \
-        if (queue->task == task->next)                                 \
-          break;                                                       \
-                                                                       \
-        task = task->next;                                             \
-      }                                                                        \
-    }                                                                  \
-  }                                                                    \
-} while(0)
+  /* Save the timeout */
+  if (task) {
+    schedule->timeout = &queue->timeout;
+    SILC_LOG_DEBUG(("timeout: sec=%d, usec=%d", schedule->timeout->tv_sec,
+                   schedule->timeout->tv_usec));
+  }
+}
 
-/* Calculates next timeout for select(). This is the timeout value
-   when at earliest some of the timeout tasks expire. If this is in the
-   past, they will be run now. This macro is used by the silc_schedule
-   function. */
-/* This must be called with holding the schedule->lock and the
-   schedule->timeout_queue->lock */
-
-#define SILC_SCHEDULE_SELECT_TIMEOUT                                       \
-do {                                                                       \
-  if (schedule->timeout_queue && schedule->timeout_queue->valid == TRUE) {  \
-    queue = schedule->timeout_queue;                                       \
-    task = NULL;                                                           \
-                                                                           \
-    /* Get the current time */                                             \
-    silc_gettimeofday(&curtime);                                           \
-    schedule->timeout = NULL;                                              \
-                                                                           \
-    /* First task in the task queue has always the smallest timeout. */            \
-    task = queue->task;                                                            \
-    while(1) {                                                             \
-      if (task && task->valid == TRUE) {                                   \
-                                                                           \
-       /* If the timeout is in past, we will run the task and all other    \
-          timeout tasks from the past. */                                  \
-       if (silc_task_timeout_compare(&task->timeout, &curtime)) {          \
-         SILC_SCHEDULE_RUN_TIMEOUT_TASKS;                                  \
-                                                                           \
-         /* The task(s) has expired and doesn't exist on the task queue    \
-            anymore. We continue with new timeout. */                      \
-          queue = schedule->timeout_queue;                                 \
-          task = queue->task;                                              \
-          if (task == NULL || task->valid == FALSE)                        \
-            break;                                                         \
-         goto cont;                                                        \
-        } else {                                                           \
- cont:                                                                     \
-          /* Calculate the next timeout for select() */                            \
-          queue->timeout.tv_sec = task->timeout.tv_sec - curtime.tv_sec;    \
-          queue->timeout.tv_usec = task->timeout.tv_usec - curtime.tv_usec; \
-         if (queue->timeout.tv_sec < 0)                                    \
-            queue->timeout.tv_sec = 0;                                     \
-                                                                           \
-          /* We wouldn't want to go under zero, check for it. */           \
-          if (queue->timeout.tv_usec < 0) {                                \
-            queue->timeout.tv_sec -= 1;                                            \
-           if (queue->timeout.tv_sec < 0)                                  \
-              queue->timeout.tv_sec = 0;                                   \
-            queue->timeout.tv_usec += 1000000L;                                    \
-          }                                                                \
-        }                                                                  \
-        /* We've got the timeout value */                                  \
-       break;                                                              \
-      }        else {                                                              \
-        /* Task is not valid, remove it and try next one. */               \
-       silc_task_remove(queue, task);                                      \
-        task = queue->task;                                                \
-        if (queue->task == NULL)                                           \
-          break;                                                           \
-      }                                                                            \
-    }                                                                      \
-    /* Save the timeout */                                                 \
-    if (task)                                                              \
-      schedule->timeout = &queue->timeout;                                 \
-  }                                                                        \
-} while(0)
-
-/* Execute generic tasks. These are executed only and only if for the
-   specific fd there wasn't other non-timeout tasks. This checks the earlier
-   set fd list, thus the generic tasks apply to all specified fd's. All the
-   generic tasks are executed at once. */
-/* This must be called holding the schedule->lock and the
-   schedule->generic_queue->lock. */
-
-#define SILC_SCHEDULE_RUN_GENERIC_TASKS                                             \
-do {                                                                        \
-  if (is_run == FALSE) {                                                    \
-    SILC_LOG_DEBUG(("Running generic tasks"));                              \
-    for (i = 0; i <= schedule->fd_list.last_fd; i++)                        \
-      if (schedule->fd_list.fd[i] != -1) {                                  \
-                                                                            \
-       /* Check whether this fd is select()ed. */                           \
-       if ((FD_ISSET(i, &schedule->in)) || (FD_ISSET(i, &schedule->out))) { \
-                                                                            \
-         /* It was selected. Now find the tasks from task queue and execute \
-            all generic tasks. */                                           \
-         if (schedule->generic_queue && schedule->generic_queue->valid) {   \
-           queue = schedule->generic_queue;                                 \
-                                                                            \
-           if (!queue->task)                                                \
-             break;                                                         \
-                                                                            \
-           task = queue->task;                                              \
-                                                                            \
-           while(1) {                                                       \
-             /* Validity of the task is checked always before and after     \
-                execution beacuse the task might have been unregistered     \
-                in the callback function, ie. it is not valid anymore. */   \
-                                                                            \
-             if (task->valid && schedule->fd_list.fd[i] != -1) {            \
-               /* Task ready for reading */                                 \
-               if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_READ))) {    \
-                  silc_mutex_unlock(queue->lock);                           \
-                  silc_mutex_unlock(schedule->lock);                        \
-                 task->callback(queue, SILC_TASK_READ,                      \
-                                task->context, i);                          \
-                  silc_mutex_lock(schedule->lock);                          \
-                  silc_mutex_lock(queue->lock);                                     \
-               }                                                            \
-             }                                                              \
-                                                                            \
-             if (task->valid && schedule->fd_list.fd[i] != -1) {            \
-               /* Task ready for writing */                                 \
-               if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_WRITE))) {   \
-                  silc_mutex_unlock(queue->lock);                           \
-                  silc_mutex_unlock(schedule->lock);                        \
-                 task->callback(queue, SILC_TASK_WRITE,                     \
-                                task->context, i);                          \
-                  silc_mutex_lock(schedule->lock);                          \
-                  silc_mutex_lock(queue->lock);                                     \
-               }                                                            \
-             }                                                              \
-                                                                            \
-             if (!task->valid) {                                            \
-               /* Invalid (unregistered) tasks are removed from the         \
-                  task queue. */                                            \
-               if (queue->task == task->next) {                             \
-                 silc_task_remove(queue, task);                             \
-                 break;                                                     \
-               }                                                            \
-                                                                            \
-               task = task->next;                                           \
-               silc_task_remove(queue, task->prev);                         \
-               continue;                                                    \
-             }                                                              \
-                                                                            \
-             /* Break if there isn't more tasks in the queue */             \
-             if (queue->task == task->next)                                 \
-               break;                                                       \
-                                                                            \
-             task = task->next;                                             \
-           }                                                                \
-         }                                                                  \
-       }                                                                    \
-      }                                                                             \
-  }                                                                         \
-} while(0)
+/* Runs the scheduler once and then returns. */
 
 bool silc_schedule_one(SilcSchedule schedule, int timeout_usecs)
 {
   struct timeval timeout;
-  int is_run, i;
-  SilcTask task;
-  SilcTaskQueue queue;
-  struct timeval curtime;
   int ret;
 
   SILC_LOG_DEBUG(("In scheduler loop"));
 
   if (!schedule->is_locked)
-    silc_mutex_lock(schedule->lock);
+    SILC_SCHEDULE_LOCK(schedule);
+
+  /* Deliver signals if any has been set to be called */
+  if (schedule->signal_tasks) {
+    SILC_SCHEDULE_UNLOCK(schedule);
+    silc_schedule_internal_signals_call(schedule->internal, schedule);
+    schedule->signal_tasks = FALSE;
+    SILC_SCHEDULE_LOCK(schedule);
+  }
 
   /* If the task queues aren't initialized or we aren't valid anymore
      we will return */
   if ((!schedule->fd_queue && !schedule->timeout_queue 
        && !schedule->generic_queue) || schedule->valid == FALSE) {
     SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
+    if (!schedule->is_locked)
+      SILC_SCHEDULE_UNLOCK(schedule);
     return FALSE;
   }
 
-  /* Clear everything */
-  FD_ZERO(&schedule->in);
-  FD_ZERO(&schedule->out);
-  schedule->max_fd = -1;
-  is_run = FALSE;
-
   /* Calculate next timeout for silc_select(). This is the timeout value
      when at earliest some of the timeout tasks expire. */
   silc_mutex_lock(schedule->timeout_queue->lock);
-  SILC_SCHEDULE_SELECT_TIMEOUT;
+  silc_schedule_select_timeout(schedule);
   silc_mutex_unlock(schedule->timeout_queue->lock);
 
-  /* Add the file descriptors to the fd sets. These are the non-timeout
-     tasks. The silc_select() listens to these file descriptors. */
-  SILC_SCHEDULE_SELECT_TASKS;
-
-  if (schedule->max_fd == -1 && !schedule->timeout)
-    return FALSE;
-
-  if (schedule->timeout) {
-    SILC_LOG_DEBUG(("timeout: sec=%d, usec=%d", schedule->timeout->tv_sec,
-                   schedule->timeout->tv_usec));
-  }
-
   if (timeout_usecs >= 0) {
     timeout.tv_sec = 0;
     timeout.tv_usec = timeout_usecs;
     schedule->timeout = &timeout;
   }
 
-  silc_mutex_unlock(schedule->lock);
+  SILC_SCHEDULE_UNLOCK(schedule);
 
   /* This is the main select(). The program blocks here until some
      of the selected file descriptors change status or the selected
      timeout expires. */
   SILC_LOG_DEBUG(("Select"));
-  ret = silc_select(schedule->max_fd + 1, &schedule->in,
-                   &schedule->out, 0, schedule->timeout);
+  ret = silc_select(schedule->fd_list, schedule->last_fd + 1, 
+                   schedule->timeout);
 
-  silc_mutex_lock(schedule->lock);
+  SILC_SCHEDULE_LOCK(schedule);
 
   switch (ret) {
   case -1:
@@ -666,27 +636,19 @@ bool silc_schedule_one(SilcSchedule schedule, int timeout_usecs)
     break;
   case 0:
     /* Timeout */
-    SILC_LOG_DEBUG(("Running timeout tasks"));
     silc_mutex_lock(schedule->timeout_queue->lock);
-    silc_gettimeofday(&curtime);
-    SILC_SCHEDULE_RUN_TIMEOUT_TASKS;
+    silc_schedule_dispatch_timeout(schedule, FALSE);
     silc_mutex_unlock(schedule->timeout_queue->lock);
     break;
   default:
     /* There is some data available now */
     SILC_LOG_DEBUG(("Running non-timeout tasks"));
-    silc_mutex_lock(schedule->fd_queue->lock);
-    SILC_SCHEDULE_RUN_TASKS;
-    silc_mutex_unlock(schedule->fd_queue->lock);
-
-    silc_mutex_lock(schedule->generic_queue->lock);
-    SILC_SCHEDULE_RUN_GENERIC_TASKS;
-    silc_mutex_unlock(schedule->generic_queue->lock);
+    silc_schedule_dispatch_nontimeout(schedule);
     break;
   }
 
   if (!schedule->is_locked)
-    silc_mutex_unlock(schedule->lock);
+    SILC_SCHEDULE_UNLOCK(schedule);
 
   return TRUE;
 }
@@ -704,14 +666,14 @@ void silc_schedule(SilcSchedule schedule)
     return;
   }
 
-  silc_mutex_lock(schedule->lock);
+  SILC_SCHEDULE_LOCK(schedule);
   schedule->is_locked = TRUE;
 
   /* Start the scheduler loop */
   while (silc_schedule_one(schedule, -1)) 
     ;
 
-  silc_mutex_unlock(schedule->lock);
+  SILC_SCHEDULE_UNLOCK(schedule);
 }
 
 /* Wakes up the scheduler. This is used only in multi-threaded
@@ -725,8 +687,640 @@ void silc_schedule_wakeup(SilcSchedule schedule)
 {
 #ifdef SILC_THREADS
   SILC_LOG_DEBUG(("Wakeup scheduler"));
-  silc_mutex_lock(schedule->lock);
-  silc_schedule_wakeup_internal(schedule->wakeup);
-  silc_mutex_unlock(schedule->lock);
+  SILC_SCHEDULE_LOCK(schedule);
+  silc_schedule_internal_wakeup(schedule->internal);
+  SILC_SCHEDULE_UNLOCK(schedule);
 #endif
 }
+
+/* Returns the application specific context that was saved into the
+   scheduler in silc_schedule_init function.  The context is also
+   returned to application in task callback functions, but this function
+   may be used to get it as well if needed. */
+
+void *silc_schedule_get_context(SilcSchedule schedule)
+{
+  return schedule->app_context;
+}
+
+/* Add new task to the scheduler */
+
+SilcTask silc_schedule_task_add(SilcSchedule schedule, SilcUInt32 fd,
+                               SilcTaskCallback callback, void *context, 
+                               long seconds, long useconds, 
+                               SilcTaskType type, 
+                               SilcTaskPriority priority)
+{
+  SilcTask newtask;
+  SilcTaskQueue queue;
+  int timeout = FALSE;
+
+  if (!schedule->valid)
+    return NULL;
+
+  SILC_LOG_DEBUG(("Registering new task, fd=%d type=%d priority=%d", fd, 
+                 type, priority));
+
+  queue = SILC_SCHEDULE_GET_QUEUE(type);
+    
+  /* If the task is generic task, we check whether this task has already
+     been registered. Generic tasks are registered only once and after that
+     the same task applies to all file descriptors to be registered. */
+  if (type == SILC_TASK_GENERIC) {
+    silc_mutex_lock(queue->lock);
+
+    if (queue->task) {
+      SilcTask task = queue->task;
+      while(1) {
+       if ((task->callback == callback) && (task->context == context)) {
+         SILC_LOG_DEBUG(("Found matching generic task, using the match"));
+         
+         silc_mutex_unlock(queue->lock);
+
+         /* Add the fd to be listened, the task found now applies to this
+            fd as well. */
+         silc_schedule_set_listen_fd(schedule, fd, SILC_TASK_READ, FALSE);
+         return task;
+       }
+       
+       if (queue->task == task->next)
+         break;
+       
+       task = task->next;
+      }
+    }
+
+    silc_mutex_unlock(queue->lock);
+  }
+
+  newtask = silc_calloc(1, sizeof(*newtask));
+  newtask->fd = fd;
+  newtask->context = context;
+  newtask->callback = callback;
+  newtask->valid = TRUE;
+  newtask->priority = priority;
+  newtask->type = type;
+  newtask->next = newtask;
+  newtask->prev = newtask;
+
+  /* Create timeout if marked to be timeout task */
+  if (((seconds + useconds) > 0) && (type == SILC_TASK_TIMEOUT)) {
+    silc_gettimeofday(&newtask->timeout);
+    newtask->timeout.tv_sec += seconds + (useconds / 1000000L);
+    newtask->timeout.tv_usec += (useconds % 1000000L);
+    if (newtask->timeout.tv_usec > 999999L) {
+      newtask->timeout.tv_sec += 1;
+      newtask->timeout.tv_usec -= 1000000L;
+    }
+    timeout = TRUE;
+  }
+
+  /* If the task is non-timeout task we have to tell the scheduler that we
+     would like to have these tasks scheduled at some odd distant future. */
+  if (type != SILC_TASK_TIMEOUT)
+    silc_schedule_set_listen_fd(schedule, fd, SILC_TASK_READ, FALSE);
+
+  silc_mutex_lock(queue->lock);
+
+  /* Is this first task of the queue? */
+  if (queue->task == NULL) {
+    queue->task = newtask;
+    silc_mutex_unlock(queue->lock);
+    return newtask;
+  }
+
+  if (timeout)
+    newtask = silc_task_add_timeout(queue, newtask, priority);
+  else
+    newtask = silc_task_add(queue, newtask, priority);
+
+  silc_mutex_unlock(queue->lock);
+
+  return newtask;
+}
+
+/* Removes a task from the scheduler */
+
+void silc_schedule_task_del(SilcSchedule schedule, SilcTask task)
+{
+  SilcTaskQueue queue = SILC_SCHEDULE_GET_QUEUE(task->type);
+
+  /* Unregister all tasks */
+  if (task == SILC_ALL_TASKS) {
+    SilcTask next;
+    SILC_LOG_DEBUG(("Unregistering all tasks at once"));
+
+    silc_mutex_lock(queue->lock);
+
+    if (!queue->task) {
+      silc_mutex_unlock(queue->lock);
+      return;
+    }
+
+    next = queue->task;
+    
+    while(1) {
+      if (next->valid)
+       next->valid = FALSE;
+      if (queue->task == next->next)
+       break;
+      next = next->next;
+    }
+
+    silc_mutex_unlock(queue->lock);
+    return;
+  }
+
+  SILC_LOG_DEBUG(("Unregistering task"));
+
+  silc_mutex_lock(queue->lock);
+
+  /* Unregister the specific task */
+  if (task->valid)
+    task->valid = FALSE;
+
+  silc_mutex_unlock(queue->lock);
+}
+
+/* Remove task by fd */
+
+void silc_schedule_task_del_by_fd(SilcSchedule schedule, SilcUInt32 fd)
+{
+  SILC_LOG_DEBUG(("Unregister task by fd %d", fd));
+
+  silc_task_del_by_fd(schedule->timeout_queue, fd);
+  silc_task_del_by_fd(schedule->fd_queue, fd);
+}
+
+/* Remove task by task callback. */
+
+void silc_schedule_task_del_by_callback(SilcSchedule schedule,
+                                       SilcTaskCallback callback)
+{
+  SILC_LOG_DEBUG(("Unregister task by callback"));
+
+  silc_task_del_by_callback(schedule->timeout_queue, callback);
+  silc_task_del_by_callback(schedule->fd_queue, callback);
+  silc_task_del_by_callback(schedule->generic_queue, callback);
+}
+
+/* Remove task by context. */
+
+void silc_schedule_task_del_by_context(SilcSchedule schedule, void *context)
+{
+  SILC_LOG_DEBUG(("Unregister task by context"));
+
+  silc_task_del_by_context(schedule->timeout_queue, context);
+  silc_task_del_by_context(schedule->fd_queue, context);
+  silc_task_del_by_context(schedule->generic_queue, context);
+}
+
+/* Sets a file descriptor to be listened by select() in scheduler. One can
+   call this directly if wanted. This can be called multiple times for
+   one file descriptor to set different iomasks. */
+
+void silc_schedule_set_listen_fd(SilcSchedule schedule, SilcUInt32 fd,
+                                SilcTaskEvent mask, bool send_events)
+{
+  int i;
+  bool found = FALSE;
+
+  if (!schedule->valid)
+    return;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  for (i = 0; i < schedule->max_fd; i++)
+    if (schedule->fd_list[i].fd == fd) {
+      schedule->fd_list[i].fd = fd;
+      schedule->fd_list[i].events = mask;
+      if (i > schedule->last_fd)
+       schedule->last_fd = i;
+      found = TRUE;
+      if (send_events) {
+       schedule->fd_list[i].revents = mask;
+       silc_schedule_dispatch_nontimeout(schedule);
+      }
+      break;
+    }
+
+  if (!found)
+    for (i = 0; i < schedule->max_fd; i++)
+      if (schedule->fd_list[i].events == 0) {
+       schedule->fd_list[i].fd = fd;
+       schedule->fd_list[i].events = mask;
+       if (i > schedule->last_fd)
+         schedule->last_fd = i;
+       if (send_events) {
+         schedule->fd_list[i].revents = mask;
+         silc_schedule_dispatch_nontimeout(schedule);
+       }
+       break;
+      }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Removes a file descriptor from listen list. */
+
+void silc_schedule_unset_listen_fd(SilcSchedule schedule, SilcUInt32 fd)
+{
+  int i;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  SILC_LOG_DEBUG(("Unset listen fd %d", fd));
+
+  for (i = 0; i < schedule->max_fd; i++)
+    if (schedule->fd_list[i].fd == fd) {
+      schedule->fd_list[i].fd = 0;
+      schedule->fd_list[i].events = 0;
+      if (schedule->last_fd == i)
+       schedule->last_fd = schedule->max_fd - 1;
+      break;
+    }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Register a new signal */
+
+void silc_schedule_signal_register(SilcSchedule schedule, SilcUInt32 signal,
+                                  SilcTaskCallback callback, void *context)
+{
+  silc_schedule_internal_signal_register(schedule->internal, signal,
+                                        callback, context);
+}
+
+/* Unregister a new signal */
+
+void silc_schedule_signal_unregister(SilcSchedule schedule, SilcUInt32 signal,
+                                    SilcTaskCallback callback, void *context)
+{
+  silc_schedule_internal_signal_unregister(schedule->internal, signal,
+                                          callback, context);
+}
+
+/* Call signal indicated by `signal'. */
+
+void silc_schedule_signal_call(SilcSchedule schedule, SilcUInt32 signal)
+{
+  /* Mark that signals needs to be delivered later. */
+  silc_schedule_internal_signal_call(schedule->internal, signal);
+  schedule->signal_tasks = TRUE;
+}
+
+/* Allocates a newtask task queue into the scheduler */
+
+static void silc_task_queue_alloc(SilcTaskQueue *queue)
+{
+  *queue = silc_calloc(1, sizeof(**queue));
+  silc_mutex_alloc(&(*queue)->lock);
+}
+
+/* Free's a task queue. */
+
+static void silc_task_queue_free(SilcTaskQueue queue)
+{
+  silc_mutex_free(queue->lock);
+  memset(queue, 'F', sizeof(*queue));
+  silc_free(queue);
+}
+
+/* Return task by its fd. */
+
+static SilcTask silc_task_find(SilcTaskQueue queue, SilcUInt32 fd)
+{
+  SilcTask next;
+
+  if (!queue->task)
+    return NULL;
+
+  next = queue->task;
+
+  while (1) {
+    if (next->fd == fd)
+      return next;
+    if (queue->task == next->next)
+      return NULL;
+    next = next->next;
+  }
+
+  return NULL;
+}
+
+/* Adds a non-timeout task into the task queue. This function is used
+   by silc_task_register function. Returns a pointer to the registered 
+   task. */
+
+static SilcTask silc_task_add(SilcTaskQueue queue, SilcTask newtask, 
+                             SilcTaskPriority priority)
+{
+  SilcTask task, next, prev;
+
+  /* Take the first task in the queue */
+  task = queue->task;
+
+  switch(priority) {
+  case SILC_TASK_PRI_LOW:
+    /* Lowest priority. The task is added at the end of the list. */
+    prev = task->prev;
+    newtask->prev = prev;
+    newtask->next = task;
+    prev->next = newtask;
+    task->prev = newtask;
+    break;
+  case SILC_TASK_PRI_NORMAL:
+    /* Normal priority. The task is added before lower priority tasks
+       but after tasks with higher priority. */
+    prev = task->prev;
+    while(prev != task) {
+      if (prev->priority > SILC_TASK_PRI_LOW)
+       break;
+      prev = prev->prev;
+    }
+    if (prev == task) {
+      /* There are only lower priorities in the list, we will
+        sit before them and become the first task in the queue. */
+      prev = task->prev;
+      newtask->prev = prev;
+      newtask->next = task;
+      task->prev = newtask;
+      prev->next = newtask;
+
+      /* We are now the first task in queue */
+      queue->task = newtask;
+    } else {
+      /* Found a spot from the list, add the task to the list. */
+      next = prev->next;
+      newtask->prev = prev;
+      newtask->next = next;
+      prev->next = newtask;
+      next->prev = newtask;
+    }
+    break;
+  default:
+    silc_free(newtask);
+    return NULL;
+  }
+
+  return newtask;
+}
+
+/* Return the timeout task with smallest timeout. */
+
+static SilcTask silc_task_get_first(SilcTaskQueue queue, SilcTask first)
+{
+  SilcTask prev, task;
+
+  prev = first->prev;
+
+  if (first == prev)
+    return first;
+
+  task = first;
+  while (1) {
+    if (first == prev)
+      break;
+
+    if (silc_compare_timeval(&prev->timeout, &task->timeout))
+      task = prev;
+
+    prev = prev->prev;
+  }
+
+  return task;
+}
+
+/* Adds a timeout task into the task queue. This function is used by
+   silc_task_register function. Returns a pointer to the registered 
+   task. Timeout tasks are sorted by their timeout value in ascending
+   order. The priority matters if there are more than one task with
+   same timeout. */
+
+static SilcTask silc_task_add_timeout(SilcTaskQueue queue, SilcTask newtask,
+                                     SilcTaskPriority priority)
+{
+  SilcTask task, prev, next;
+
+  /* Take the first task in the queue */
+  task = queue->task;
+
+  /* Take last task from the list */
+  prev = task->prev;
+    
+  switch(priority) {
+  case SILC_TASK_PRI_LOW:
+    /* Lowest priority. The task is added at the end of the list. */
+    while(prev != task) {
+
+      /* If we have longer timeout than with the task head of us
+        we have found our spot. */
+      if (silc_compare_timeval(&prev->timeout, &newtask->timeout))
+       break;
+
+      /* If we are equal size of timeout we will be after it. */
+      if (!silc_compare_timeval(&newtask->timeout, &prev->timeout))
+       break;
+
+      /* We have shorter timeout, compare to next one. */
+      prev = prev->prev;
+    }
+    /* Found a spot from the list, add the task to the list. */
+    next = prev->next;
+    newtask->prev = prev;
+    newtask->next = next;
+    prev->next = newtask;
+    next->prev = newtask;
+    
+    if (prev == task) {
+      /* Check if we are going to be the first task in the queue */
+      if (silc_compare_timeval(&prev->timeout, &newtask->timeout))
+       break;
+      if (!silc_compare_timeval(&newtask->timeout, &prev->timeout))
+       break;
+
+      /* We are now the first task in queue */
+      queue->task = newtask;
+    }
+    break;
+  case SILC_TASK_PRI_NORMAL:
+    /* Normal priority. The task is added before lower priority tasks
+       but after tasks with higher priority. */
+    while(prev != task) {
+
+      /* If we have longer timeout than with the task head of us
+        we have found our spot. */
+      if (silc_compare_timeval(&prev->timeout, &newtask->timeout))
+       break;
+
+      /* If we are equal size of timeout, priority kicks in place. */
+      if (!silc_compare_timeval(&newtask->timeout, &prev->timeout))
+       if (prev->priority >= SILC_TASK_PRI_NORMAL)
+         break;
+
+      /* We have shorter timeout or higher priority, compare to next one. */
+      prev = prev->prev;
+    }
+    /* Found a spot from the list, add the task to the list. */
+    next = prev->next;
+    newtask->prev = prev;
+    newtask->next = next;
+    prev->next = newtask;
+    next->prev = newtask;
+    
+    if (prev == task) {
+      /* Check if we are going to be the first task in the queue */
+      if (silc_compare_timeval(&prev->timeout, &newtask->timeout))
+       break;
+      if (!silc_compare_timeval(&newtask->timeout, &prev->timeout))
+       if (prev->priority >= SILC_TASK_PRI_NORMAL)
+         break;
+
+      /* We are now the first task in queue */
+      queue->task = newtask;
+    }
+    break;
+  default:
+    silc_free(newtask);
+    return NULL;
+  }
+
+  return newtask;
+}
+
+/* Removes (unregisters) a task from particular task queue. This function
+   is used internally by scheduler. This must be called holding the 
+   queue->lock. */
+
+static int silc_schedule_task_remove(SilcTaskQueue queue, SilcTask task)
+{
+  SilcTask first, old, next;
+
+  if (!queue || !task)
+    return FALSE;
+
+  if (!queue->task) {
+    return FALSE;
+  }
+
+  first = queue->task;
+
+  /* Unregister all tasks in queue */
+  if (task == SILC_ALL_TASKS) {
+    SILC_LOG_DEBUG(("Removing all tasks at once"));
+    next = first;
+
+    while(1) {
+      old = next->next;
+      silc_free(next);
+      if (old == first)
+       break;
+      next = old;
+    }
+
+    queue->task = NULL;
+    return TRUE;
+  }
+
+  SILC_LOG_DEBUG(("Removing task"));
+
+  /* Unregister the task */
+  old = first;
+  while(1) {
+    if (old == task) {
+      SilcTask prev, next;
+
+      prev = old->prev;
+      next = old->next;
+      prev->next = next;
+      next->prev = prev;
+
+      if (prev == old && next == old)
+       queue->task = NULL;
+      if (queue->task == old)
+       queue->task = silc_task_get_first(queue, next);
+      
+      silc_free(old);
+      return TRUE;
+    }
+    old = old->prev;
+
+    if (old == first) {
+      return FALSE;
+    }
+  }
+}
+
+static void silc_task_del_by_fd(SilcTaskQueue queue, SilcUInt32 fd)
+{
+  SilcTask next;
+
+  silc_mutex_lock(queue->lock);
+
+  if (!queue->task) {
+    silc_mutex_unlock(queue->lock);
+    return;
+  }
+
+  next = queue->task;
+
+  while(1) {
+    if (next->fd == fd)
+      next->valid = FALSE;
+    if (queue->task == next->next)
+      break;
+    next = next->next;
+  }
+
+  silc_mutex_unlock(queue->lock);
+}
+
+static void silc_task_del_by_callback(SilcTaskQueue queue,
+                                     SilcTaskCallback callback)
+{
+  SilcTask next;
+
+  silc_mutex_lock(queue->lock);
+
+  if (!queue->task) {
+    silc_mutex_unlock(queue->lock);
+    return;
+  }
+
+  next = queue->task;
+
+  while(1) {
+    if (next->callback == callback)
+      next->valid = FALSE;
+    if (queue->task == next->next)
+      break;
+    next = next->next;
+  }
+
+  silc_mutex_unlock(queue->lock);
+}
+
+static void silc_task_del_by_context(SilcTaskQueue queue, void *context)
+{
+  SilcTask next;
+
+  silc_mutex_lock(queue->lock);
+
+  if (!queue->task) {
+    silc_mutex_unlock(queue->lock);
+    return;
+  }
+
+  next = queue->task;
+
+  while(1) {
+    if (next->context == context)
+      next->valid = FALSE;
+    if (queue->task == next->next)
+      break;
+    next = next->next;
+  }
+
+  silc_mutex_unlock(queue->lock);
+}