diff --git a/lib/thread.c b/lib/thread.c
new file mode 100644
index 0000000..31bbcd7
--- /dev/null
+++ b/lib/thread.c
@@ -0,0 +1,668 @@
+/* Thread management routine
+ * Copyright (C) 1998, 2000 Kunihiro Ishiguro <kunihiro@zebra.org>
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra 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, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra 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 GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.  
+ */
+
+/* #define DEBUG */
+
+#include <zebra.h>
+
+#include "thread.h"
+#include "memory.h"
+#include "log.h"
+
+/* Struct timeval's tv_usec one second value.  */
+#define TIMER_SECOND_MICRO 1000000L
+
+struct timeval
+timeval_adjust (struct timeval a)
+{
+  while (a.tv_usec >= TIMER_SECOND_MICRO)
+    {
+      a.tv_usec -= TIMER_SECOND_MICRO;
+      a.tv_sec++;
+    }
+
+  while (a.tv_usec < 0)
+    {
+      a.tv_usec += TIMER_SECOND_MICRO;
+      a.tv_sec--;
+    }
+
+  if (a.tv_sec < 0)
+    {
+      a.tv_sec = 0;
+      a.tv_usec = 10;
+    }
+
+  if (a.tv_sec > TIMER_SECOND_MICRO)
+    a.tv_sec = TIMER_SECOND_MICRO;    
+
+  return a;
+}
+
+static struct timeval
+timeval_subtract (struct timeval a, struct timeval b)
+{
+  struct timeval ret;
+
+  ret.tv_usec = a.tv_usec - b.tv_usec;
+  ret.tv_sec = a.tv_sec - b.tv_sec;
+
+  return timeval_adjust (ret);
+}
+
+static int
+timeval_cmp (struct timeval a, struct timeval b)
+{
+  return (a.tv_sec == b.tv_sec
+	  ? a.tv_usec - b.tv_usec : a.tv_sec - b.tv_sec);
+}
+
+static unsigned long
+timeval_elapsed (struct timeval a, struct timeval b)
+{
+  return (((a.tv_sec - b.tv_sec) * TIMER_SECOND_MICRO)
+	  + (a.tv_usec - b.tv_usec));
+}
+
+/* List allocation and head/tail print out. */
+static void
+thread_list_debug (struct thread_list *list)
+{
+  printf ("count [%d] head [%p] tail [%p]\n",
+	  list->count, list->head, list->tail);
+}
+
+/* Debug print for thread_master. */
+void
+thread_master_debug (struct thread_master *m)
+{
+  printf ("-----------\n");
+  printf ("readlist  : ");
+  thread_list_debug (&m->read);
+  printf ("writelist : ");
+  thread_list_debug (&m->write);
+  printf ("timerlist : ");
+  thread_list_debug (&m->timer);
+  printf ("eventlist : ");
+  thread_list_debug (&m->event);
+  printf ("unuselist : ");
+  thread_list_debug (&m->unuse);
+  printf ("total alloc: [%ld]\n", m->alloc);
+  printf ("-----------\n");
+}
+
+/* Allocate new thread master.  */
+struct thread_master *
+thread_master_create ()
+{
+  return (struct thread_master *) XCALLOC (MTYPE_THREAD_MASTER,
+					   sizeof (struct thread_master));
+}
+
+/* Add a new thread to the list.  */
+static void
+thread_list_add (struct thread_list *list, struct thread *thread)
+{
+  thread->next = NULL;
+  thread->prev = list->tail;
+  if (list->tail)
+    list->tail->next = thread;
+  else
+    list->head = thread;
+  list->tail = thread;
+  list->count++;
+}
+
+/* Add a new thread just before the point.  */
+static void
+thread_list_add_before (struct thread_list *list, 
+			struct thread *point, 
+			struct thread *thread)
+{
+  thread->next = point;
+  thread->prev = point->prev;
+  if (point->prev)
+    point->prev->next = thread;
+  else
+    list->head = thread;
+  point->prev = thread;
+  list->count++;
+}
+
+/* Delete a thread from the list. */
+static struct thread *
+thread_list_delete (struct thread_list *list, struct thread *thread)
+{
+  if (thread->next)
+    thread->next->prev = thread->prev;
+  else
+    list->tail = thread->prev;
+  if (thread->prev)
+    thread->prev->next = thread->next;
+  else
+    list->head = thread->next;
+  thread->next = thread->prev = NULL;
+  list->count--;
+  return thread;
+}
+
+/* Move thread to unuse list. */
+static void
+thread_add_unuse (struct thread_master *m, struct thread *thread)
+{
+  assert (m != NULL);
+  assert (thread->next == NULL);
+  assert (thread->prev == NULL);
+  assert (thread->type == THREAD_UNUSED);
+  thread_list_add (&m->unuse, thread);
+}
+
+/* Free all unused thread. */
+static void
+thread_list_free (struct thread_master *m, struct thread_list *list)
+{
+  struct thread *t;
+  struct thread *next;
+
+  for (t = list->head; t; t = next)
+    {
+      next = t->next;
+      XFREE (MTYPE_THREAD, t);
+      list->count--;
+      m->alloc--;
+    }
+}
+
+/* Stop thread scheduler. */
+void
+thread_master_free (struct thread_master *m)
+{
+  thread_list_free (m, &m->read);
+  thread_list_free (m, &m->write);
+  thread_list_free (m, &m->timer);
+  thread_list_free (m, &m->event);
+  thread_list_free (m, &m->ready);
+  thread_list_free (m, &m->unuse);
+
+  XFREE (MTYPE_THREAD_MASTER, m);
+}
+
+/* Delete top of the list and return it. */
+static struct thread *
+thread_trim_head (struct thread_list *list)
+{
+  if (list->head)
+    return thread_list_delete (list, list->head);
+  return NULL;
+}
+
+/* Thread list is empty or not.  */
+int
+thread_empty (struct thread_list *list)
+{
+  return  list->head ? 0 : 1;
+}
+
+/* Return remain time in second. */
+unsigned long
+thread_timer_remain_second (struct thread *thread)
+{
+  struct timeval timer_now;
+
+  gettimeofday (&timer_now, NULL);
+
+  if (thread->u.sands.tv_sec - timer_now.tv_sec > 0)
+    return thread->u.sands.tv_sec - timer_now.tv_sec;
+  else
+    return 0;
+}
+
+/* Get new thread.  */
+static struct thread *
+thread_get (struct thread_master *m, u_char type,
+	    int (*func) (struct thread *), void *arg)
+{
+  struct thread *thread;
+
+  if (m->unuse.head)
+    thread = thread_trim_head (&m->unuse);
+  else
+    {
+      thread = XCALLOC (MTYPE_THREAD, sizeof (struct thread));
+      m->alloc++;
+    }
+  thread->type = type;
+  thread->master = m;
+  thread->func = func;
+  thread->arg = arg;
+  
+  return thread;
+}
+
+/* Add new read thread. */
+struct thread *
+thread_add_read (struct thread_master *m, 
+		 int (*func) (struct thread *), void *arg, int fd)
+{
+  struct thread *thread;
+
+  assert (m != NULL);
+
+  if (FD_ISSET (fd, &m->readfd))
+    {
+      zlog (NULL, LOG_WARNING, "There is already read fd [%d]", fd);
+      return NULL;
+    }
+
+  thread = thread_get (m, THREAD_READ, func, arg);
+  FD_SET (fd, &m->readfd);
+  thread->u.fd = fd;
+  thread_list_add (&m->read, thread);
+
+  return thread;
+}
+
+/* Add new write thread. */
+struct thread *
+thread_add_write (struct thread_master *m,
+		 int (*func) (struct thread *), void *arg, int fd)
+{
+  struct thread *thread;
+
+  assert (m != NULL);
+
+  if (FD_ISSET (fd, &m->writefd))
+    {
+      zlog (NULL, LOG_WARNING, "There is already write fd [%d]", fd);
+      return NULL;
+    }
+
+  thread = thread_get (m, THREAD_WRITE, func, arg);
+  FD_SET (fd, &m->writefd);
+  thread->u.fd = fd;
+  thread_list_add (&m->write, thread);
+
+  return thread;
+}
+
+/* Add timer event thread. */
+struct thread *
+thread_add_timer (struct thread_master *m,
+		  int (*func) (struct thread *), void *arg, long timer)
+{
+  struct timeval timer_now;
+  struct thread *thread;
+#ifndef TIMER_NO_SORT
+  struct thread *tt;
+#endif /* TIMER_NO_SORT */
+
+  assert (m != NULL);
+
+  thread = thread_get (m, THREAD_TIMER, func, arg);
+
+  /* Do we need jitter here? */
+  gettimeofday (&timer_now, NULL);
+  timer_now.tv_sec += timer;
+  thread->u.sands = timer_now;
+
+  /* Sort by timeval. */
+#ifdef TIMER_NO_SORT
+  thread_list_add (&m->timer, thread);
+#else
+  for (tt = m->timer.head; tt; tt = tt->next)
+    if (timeval_cmp (thread->u.sands, tt->u.sands) <= 0)
+      break;
+
+  if (tt)
+    thread_list_add_before (&m->timer, tt, thread);
+  else
+    thread_list_add (&m->timer, thread);
+#endif /* TIMER_NO_SORT */
+
+  return thread;
+}
+
+/* Add simple event thread. */
+struct thread *
+thread_add_event (struct thread_master *m,
+		  int (*func) (struct thread *), void *arg, int val)
+{
+  struct thread *thread;
+
+  assert (m != NULL);
+
+  thread = thread_get (m, THREAD_EVENT, func, arg);
+  thread->u.val = val;
+  thread_list_add (&m->event, thread);
+
+  return thread;
+}
+
+/* Cancel thread from scheduler. */
+void
+thread_cancel (struct thread *thread)
+{
+  switch (thread->type)
+    {
+    case THREAD_READ:
+      assert (FD_ISSET (thread->u.fd, &thread->master->readfd));
+      FD_CLR (thread->u.fd, &thread->master->readfd);
+      thread_list_delete (&thread->master->read, thread);
+      break;
+    case THREAD_WRITE:
+      assert (FD_ISSET (thread->u.fd, &thread->master->writefd));
+      FD_CLR (thread->u.fd, &thread->master->writefd);
+      thread_list_delete (&thread->master->write, thread);
+      break;
+    case THREAD_TIMER:
+      thread_list_delete (&thread->master->timer, thread);
+      break;
+    case THREAD_EVENT:
+      thread_list_delete (&thread->master->event, thread);
+      break;
+    case THREAD_READY:
+      thread_list_delete (&thread->master->ready, thread);
+      break;
+    default:
+      break;
+    }
+  thread->type = THREAD_UNUSED;
+  thread_add_unuse (thread->master, thread);
+}
+
+/* Delete all events which has argument value arg. */
+void
+thread_cancel_event (struct thread_master *m, void *arg)
+{
+  struct thread *thread;
+
+  thread = m->event.head;
+  while (thread)
+    {
+      struct thread *t;
+
+      t = thread;
+      thread = t->next;
+
+      if (t->arg == arg)
+	{
+	  thread_list_delete (&m->event, t);
+	  t->type = THREAD_UNUSED;
+	  thread_add_unuse (m, t);
+	}
+    }
+}
+
+#ifdef TIMER_NO_SORT
+struct timeval *
+thread_timer_wait (struct thread_master *m, struct timeval *timer_val)
+{
+  struct timeval timer_now;
+  struct timeval timer_min;
+  struct timeval *timer_wait;
+
+  gettimeofday (&timer_now, NULL);
+
+  timer_wait = NULL;
+  for (thread = m->timer.head; thread; thread = thread->next)
+    {
+      if (! timer_wait)
+	timer_wait = &thread->u.sands;
+      else if (timeval_cmp (thread->u.sands, *timer_wait) < 0)
+	timer_wait = &thread->u.sands;
+    }
+
+  if (m->timer.head)
+    {
+      timer_min = *timer_wait;
+      timer_min = timeval_subtract (timer_min, timer_now);
+      if (timer_min.tv_sec < 0)
+	{
+	  timer_min.tv_sec = 0;
+	  timer_min.tv_usec = 10;
+	}
+      timer_wait = &timer_min;
+    }
+  else
+    timer_wait = NULL;
+
+  if (timer_wait)
+    {
+      *timer_val = timer_wait;
+      return timer_val;
+    }
+  return NULL;
+}
+#else /* ! TIMER_NO_SORT */
+struct timeval *
+thread_timer_wait (struct thread_master *m, struct timeval *timer_val)
+{
+  struct timeval timer_now;
+  struct timeval timer_min;
+
+  if (m->timer.head)
+    {
+      gettimeofday (&timer_now, NULL);
+      timer_min = m->timer.head->u.sands;
+      timer_min = timeval_subtract (timer_min, timer_now);
+      if (timer_min.tv_sec < 0)
+	{
+	  timer_min.tv_sec = 0;
+	  timer_min.tv_usec = 10;
+	}
+      *timer_val = timer_min;
+      return timer_val;
+    }
+  return NULL;
+}
+#endif /* TIMER_NO_SORT */
+
+struct thread *
+thread_run (struct thread_master *m, struct thread *thread,
+	    struct thread *fetch)
+{
+  *fetch = *thread;
+  thread->type = THREAD_UNUSED;
+  thread_add_unuse (m, thread);
+  return fetch;
+}
+
+int
+thread_process_fd (struct thread_master *m, struct thread_list *list,
+		   fd_set *fdset, fd_set *mfdset)
+{
+  struct thread *thread;
+  struct thread *next;
+  int ready = 0;
+
+  for (thread = list->head; thread; thread = next)
+    {
+      next = thread->next;
+
+      if (FD_ISSET (THREAD_FD (thread), fdset))
+	{
+	  assert (FD_ISSET (THREAD_FD (thread), mfdset));
+	  FD_CLR(THREAD_FD (thread), mfdset);
+	  thread_list_delete (list, thread);
+	  thread_list_add (&m->ready, thread);
+	  thread->type = THREAD_READY;
+	  ready++;
+	}
+    }
+  return ready;
+}
+
+/* Fetch next ready thread. */
+struct thread *
+thread_fetch (struct thread_master *m, struct thread *fetch)
+{
+  int num;
+  int ready;
+  struct thread *thread;
+  fd_set readfd;
+  fd_set writefd;
+  fd_set exceptfd;
+  struct timeval timer_now;
+  struct timeval timer_val;
+  struct timeval *timer_wait;
+  struct timeval timer_nowait;
+
+  timer_nowait.tv_sec = 0;
+  timer_nowait.tv_usec = 0;
+
+  while (1)
+    {
+      /* Normal event is the highest priority.  */
+      if ((thread = thread_trim_head (&m->event)) != NULL)
+	return thread_run (m, thread, fetch);
+
+      /* Execute timer.  */
+      gettimeofday (&timer_now, NULL);
+
+      for (thread = m->timer.head; thread; thread = thread->next)
+	if (timeval_cmp (timer_now, thread->u.sands) >= 0)
+	  {
+	    thread_list_delete (&m->timer, thread);
+	    return thread_run (m, thread, fetch);
+	  }
+
+      /* If there are any ready threads, process top of them.  */
+      if ((thread = thread_trim_head (&m->ready)) != NULL)
+	return thread_run (m, thread, fetch);
+
+      /* Structure copy.  */
+      readfd = m->readfd;
+      writefd = m->writefd;
+      exceptfd = m->exceptfd;
+
+      /* Calculate select wait timer. */
+      timer_wait = thread_timer_wait (m, &timer_val);
+
+      num = select (FD_SETSIZE, &readfd, &writefd, &exceptfd, timer_wait);
+
+      if (num == 0)
+	continue;
+
+      if (num < 0)
+	{
+	  if (errno == EINTR)
+	    continue;
+
+	  zlog_warn ("select() error: %s", strerror (errno));
+	  return NULL;
+	}
+
+      /* Normal priority read thead. */
+      ready = thread_process_fd (m, &m->read, &readfd, &m->readfd);
+
+      /* Write thead. */
+      ready = thread_process_fd (m, &m->write, &writefd, &m->writefd);
+
+      if ((thread = thread_trim_head (&m->ready)) != NULL)
+	return thread_run (m, thread, fetch);
+    }
+}
+
+static unsigned long
+thread_consumed_time (RUSAGE_T *now, RUSAGE_T *start)
+{
+  unsigned long thread_time;
+
+#ifdef HAVE_RUSAGE
+  /* This is 'user + sys' time.  */
+  thread_time = timeval_elapsed (now->ru_utime, start->ru_utime);
+  thread_time += timeval_elapsed (now->ru_stime, start->ru_stime);
+#else
+  /* When rusage is not available, simple elapsed time is used.  */
+  thread_time = timeval_elapsed (*now, *start);
+#endif /* HAVE_RUSAGE */
+
+  return thread_time;
+}
+
+/* We should aim to yield after THREAD_YIELD_TIME_SLOT
+   milliseconds.  */
+int
+thread_should_yield (struct thread *thread)
+{
+  RUSAGE_T ru;
+
+  GETRUSAGE (&ru);
+
+  if (thread_consumed_time (&ru, &thread->ru) > THREAD_YIELD_TIME_SLOT)
+    return 1;
+  else
+    return 0;
+}
+
+/* We check thread consumed time. If the system has getrusage, we'll
+   use that to get indepth stats on the performance of the thread.  If
+   not - we'll use gettimeofday for some guestimation.  */
+void
+thread_call (struct thread *thread)
+{
+  unsigned long thread_time;
+  RUSAGE_T ru;
+
+  GETRUSAGE (&thread->ru);
+
+  (*thread->func) (thread);
+
+  GETRUSAGE (&ru);
+
+  thread_time = thread_consumed_time (&ru, &thread->ru);
+
+#ifdef THREAD_CONSUMED_TIME_CHECK
+  if (thread_time > 200000L)
+    {
+      /*
+       * We have a CPU Hog on our hands.
+       * Whinge about it now, so we're aware this is yet another task
+       * to fix.
+       */
+      zlog_err ("CPU HOG task %lx ran for %ldms",
+                /* FIXME: report the name of the function somehow */
+		(unsigned long) thread->func,
+		thread_time / 1000L);
+    }
+#endif /* THREAD_CONSUMED_TIME_CHECK */
+}
+
+/* Execute thread */
+struct thread *
+thread_execute (struct thread_master *m,
+                int (*func)(struct thread *), 
+                void *arg,
+                int val)
+{
+  struct thread dummy; 
+
+  memset (&dummy, 0, sizeof (struct thread));
+
+  dummy.type = THREAD_EVENT;
+  dummy.master = NULL;
+  dummy.func = func;
+  dummy.arg = arg;
+  dummy.u.val = val;
+  thread_call (&dummy);
+
+  return NULL;
+}