Merge commit '0072d11f' into tmp-learn

9 files changed, 889 insertions, 93 deletions

diff --git a/sysdep/unix/Makefile b/sysdep/unix/Makefile
index 51ab98a9..3f1a8b3a 100644
--- a/sysdep/unix/Makefile
+++ b/sysdep/unix/Makefile
@@ -1,4 +1,4 @@
-src := alloc.c io.c krt.c log.c main.c random.c
+src := alloc.c io.c io-loop.c krt.c log.c main.c random.c domain.c
 obj := $(src-o-files)
 $(all-daemon)
 $(cf-local)
diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c
index edad6209..a2384ca8 100644
--- a/sysdep/unix/alloc.c
+++ b/sysdep/unix/alloc.c
@@ -97,7 +97,7 @@ alloc_page(void)
     struct free_page *fp = SKIP_BACK(struct free_page, n, HEAD(fps->pages));
     rem_node(&fp->n);
     if ((--fps->cnt < fps->min) && !shutting_down)
-      ev_schedule(&fps->cleanup);
+      ev_send(&global_work_list, &fps->cleanup);
 
     bzero(fp, page_size);
     return fp;
@@ -124,7 +124,7 @@ free_page(void *ptr)
   add_tail(&fps->pages, &fp->n);
 
   if ((++fps->cnt > fps->max) && !shutting_down)
-    ev_schedule(&fps->cleanup);
+    ev_send(&global_work_list, &fps->cleanup);
 #endif
 }
 
diff --git a/sysdep/unix/domain.c b/sysdep/unix/domain.c
new file mode 100644
index 00000000..0a5858a6
--- /dev/null
+++ b/sysdep/unix/domain.c
@@ -0,0 +1,116 @@
+/*
+ *	BIRD Locking
+ *
+ *	(c) 2020 Maria Matejka <mq@jmq.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#undef LOCAL_DEBUG
+
+#undef DEBUG_LOCKING
+
+#include "lib/birdlib.h"
+#include "lib/locking.h"
+#include "lib/resource.h"
+#include "lib/timer.h"
+
+#include "conf/conf.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdatomic.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ *	Locking subsystem
+ */
+
+_Thread_local struct lock_order locking_stack = {};
+_Thread_local struct domain_generic **last_locked = NULL;
+
+#define ASSERT_NO_LOCK	ASSERT_DIE(last_locked == NULL)
+
+struct domain_generic {
+  pthread_mutex_t mutex;
+  uint order;
+  struct domain_generic **prev;
+  struct lock_order *locked_by;
+  const char *name;
+};
+
+#define DOMAIN_INIT(_name, _order) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _name, .order = _order }
+
+static struct domain_generic the_bird_domain_gen = DOMAIN_INIT("The BIRD", OFFSETOF(struct lock_order, the_bird));
+
+DOMAIN(the_bird) the_bird_domain = { .the_bird = &the_bird_domain_gen };
+
+struct domain_generic *
+domain_new(const char *name, uint order)
+{
+  ASSERT_DIE(order < sizeof(struct lock_order));
+  struct domain_generic *dg = xmalloc(sizeof(struct domain_generic));
+  *dg = (struct domain_generic) DOMAIN_INIT(name, order);
+  return dg;
+}
+
+void
+domain_free(struct domain_generic *dg)
+{
+  pthread_mutex_destroy(&dg->mutex);
+  xfree(dg);
+}
+
+uint dg_order(struct domain_generic *dg)
+{
+  return dg->order;
+}
+
+void do_lock(struct domain_generic *dg, struct domain_generic **lsp)
+{
+  if ((char *) lsp - (char *) &locking_stack != dg->order)
+    bug("Trying to lock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack);
+
+  if (lsp <= last_locked)
+    bug("Trying to lock in a bad order");
+  if (*lsp)
+    bug("Inconsistent locking stack state on lock");
+
+  btime lock_begin = current_time();
+  pthread_mutex_lock(&dg->mutex);
+  btime duration = current_time() - lock_begin;
+  if (config && (duration > config->watchdog_warning))
+    log(L_WARN "Locking of %s took %d ms", dg->name, (int) (duration TO_MS));
+
+  if (dg->prev || dg->locked_by)
+    bug("Previous unlock not finished correctly");
+  dg->prev = last_locked;
+  *lsp = dg;
+  last_locked = lsp;
+  dg->locked_by = &locking_stack;
+}
+
+void do_unlock(struct domain_generic *dg, struct domain_generic **lsp)
+{
+  if ((char *) lsp - (char *) &locking_stack != dg->order)
+    bug("Trying to unlock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack);
+
+  if (dg->locked_by != &locking_stack)
+    bug("Inconsistent domain state on unlock");
+  if ((last_locked != lsp) || (*lsp != dg))
+    bug("Inconsistent locking stack state on unlock");
+  dg->locked_by = NULL;
+  last_locked = dg->prev;
+  *lsp = NULL;
+  dg->prev = NULL;
+  pthread_mutex_unlock(&dg->mutex);
+}
diff --git a/sysdep/unix/io-loop.c b/sysdep/unix/io-loop.c
new file mode 100644
index 00000000..3e3fc31a
--- /dev/null
+++ b/sysdep/unix/io-loop.c
@@ -0,0 +1,578 @@
+/*
+ *	BIRD -- I/O and event loop
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <pthread.h>
+#include <time.h>
+#include <sys/time.h>
+
+#include "nest/bird.h"
+
+#include "lib/buffer.h"
+#include "lib/lists.h"
+#include "lib/resource.h"
+#include "lib/event.h"
+#include "lib/timer.h"
+#include "lib/socket.h"
+
+#include "lib/io-loop.h"
+#include "sysdep/unix/io-loop.h"
+#include "conf/conf.h"
+
+#define THREAD_STACK_SIZE	65536	/* To be lowered in near future */
+
+/*
+ *	Current thread context
+ */
+
+_Thread_local struct birdloop *birdloop_current;
+static _Thread_local struct birdloop *birdloop_wakeup_masked;
+static _Thread_local uint birdloop_wakeup_masked_count;
+
+event_list *
+birdloop_event_list(struct birdloop *loop)
+{
+  return &loop->event_list;
+}
+
+struct timeloop *
+birdloop_time_loop(struct birdloop *loop)
+{
+  return &loop->time;
+}
+
+_Bool
+birdloop_inside(struct birdloop *loop)
+{
+  for (struct birdloop *c = birdloop_current; c; c = c->prev_loop)
+    if (loop == c)
+      return 1;
+
+  return 0;
+}
+
+/*
+ *	Wakeup code for birdloop
+ */
+
+static void
+pipe_new(int *pfds)
+{
+  int rv = pipe(pfds);
+  if (rv < 0)
+    die("pipe: %m");
+
+  if (fcntl(pfds[0], F_SETFL, O_NONBLOCK) < 0)
+    die("fcntl(O_NONBLOCK): %m");
+
+  if (fcntl(pfds[1], F_SETFL, O_NONBLOCK) < 0)
+    die("fcntl(O_NONBLOCK): %m");
+}
+
+void
+pipe_drain(int fd)
+{
+  char buf[64];
+  int rv;
+  
+ try:
+  rv = read(fd, buf, 64);
+  if (rv < 0)
+  {
+    if (errno == EINTR)
+      goto try;
+    if (errno == EAGAIN)
+      return;
+    die("wakeup read: %m");
+  }
+  if (rv == 64)
+    goto try;
+}
+
+void
+pipe_kick(int fd)
+{
+  u64 v = 1;
+  int rv;
+
+ try:
+  rv = write(fd, &v, sizeof(u64));
+  if (rv < 0)
+  {
+    if (errno == EINTR)
+      goto try;
+    if (errno == EAGAIN)
+      return;
+    die("wakeup write: %m");
+  }
+}
+
+static inline void
+wakeup_init(struct birdloop *loop)
+{
+  pipe_new(loop->wakeup_fds);
+}
+
+static inline void
+wakeup_drain(struct birdloop *loop)
+{
+  pipe_drain(loop->wakeup_fds[0]);
+}
+
+static inline void
+wakeup_do_kick(struct birdloop *loop)
+{
+  pipe_kick(loop->wakeup_fds[1]);
+}
+
+static inline void
+birdloop_do_ping(struct birdloop *loop)
+{
+  if (atomic_fetch_add_explicit(&loop->ping_sent, 1, memory_order_acq_rel))
+    return;
+
+  if (loop == birdloop_wakeup_masked)
+    birdloop_wakeup_masked_count++;
+  else
+    wakeup_do_kick(loop);
+}
+
+void
+birdloop_ping(struct birdloop *loop)
+{
+  if (birdloop_inside(loop) && !loop->ping_pending)
+    loop->ping_pending++;
+  else
+    birdloop_do_ping(loop);
+}
+
+
+/*
+ *	Sockets
+ */
+
+static void
+sockets_init(struct birdloop *loop)
+{
+  init_list(&loop->sock_list);
+  loop->sock_num = 0;
+
+  BUFFER_INIT(loop->poll_sk, loop->pool, 4);
+  BUFFER_INIT(loop->poll_fd, loop->pool, 4);
+  loop->poll_changed = 1;	/* add wakeup fd */
+}
+
+static void
+sockets_add(struct birdloop *loop, sock *s)
+{
+  add_tail(&loop->sock_list, &s->n);
+  loop->sock_num++;
+
+  s->index = -1;
+  loop->poll_changed = 1;
+
+  birdloop_ping(loop);
+}
+
+void
+sk_start(sock *s)
+{
+  ASSERT_DIE(birdloop_current != &main_birdloop);
+  sockets_add(birdloop_current, s);
+}
+
+static void
+sockets_remove(struct birdloop *loop, sock *s)
+{
+  rem_node(&s->n);
+  loop->sock_num--;
+
+  if (s->index >= 0)
+  {
+    loop->poll_sk.data[s->index] = NULL;
+    s->index = -1;
+    loop->poll_changed = 1;
+    loop->close_scheduled = 1;
+    birdloop_ping(loop);
+  }
+  else
+    close(s->fd);
+}
+
+void
+sk_stop(sock *s)
+{
+  sockets_remove(birdloop_current, s);
+}
+
+static inline uint sk_want_events(sock *s)
+{ return (s->rx_hook ? POLLIN : 0) | ((s->ttx != s->tpos) ? POLLOUT : 0); }
+
+/*
+FIXME: this should be called from sock code
+
+static void
+sockets_update(struct birdloop *loop, sock *s)
+{
+  if (s->index >= 0)
+    loop->poll_fd.data[s->index].events = sk_want_events(s);
+}
+*/
+
+static void
+sockets_prepare(struct birdloop *loop)
+{
+  BUFFER_SET(loop->poll_sk, loop->sock_num + 1);
+  BUFFER_SET(loop->poll_fd, loop->sock_num + 1);
+
+  struct pollfd *pfd = loop->poll_fd.data;
+  sock **psk = loop->poll_sk.data;
+  uint i = 0;
+  node *n;
+
+  WALK_LIST(n, loop->sock_list)
+  {
+    sock *s = SKIP_BACK(sock, n, n);
+
+    ASSERT(i < loop->sock_num);
+
+    s->index = i;
+    *psk = s;
+    pfd->fd = s->fd;
+    pfd->events = sk_want_events(s);
+    pfd->revents = 0;
+
+    pfd++;
+    psk++;
+    i++;
+  }
+
+  ASSERT(i == loop->sock_num);
+
+  /* Add internal wakeup fd */
+  *psk = NULL;
+  pfd->fd = loop->wakeup_fds[0];
+  pfd->events = POLLIN;
+  pfd->revents = 0;
+
+  loop->poll_changed = 0;
+}
+
+static void
+sockets_close_fds(struct birdloop *loop)
+{
+  struct pollfd *pfd = loop->poll_fd.data;
+  sock **psk = loop->poll_sk.data;
+  int poll_num = loop->poll_fd.used - 1;
+
+  int i;
+  for (i = 0; i < poll_num; i++)
+    if (psk[i] == NULL)
+      close(pfd[i].fd);
+
+  loop->close_scheduled = 0;
+}
+
+int sk_read(sock *s, int revents);
+int sk_write(sock *s);
+
+static void
+sockets_fire(struct birdloop *loop)
+{
+  struct pollfd *pfd = loop->poll_fd.data;
+  sock **psk = loop->poll_sk.data;
+  int poll_num = loop->poll_fd.used - 1;
+
+  times_update();
+
+  /* Last fd is internal wakeup fd */
+  if (pfd[poll_num].revents & POLLIN)
+    wakeup_drain(loop);
+
+  int i;
+  for (i = 0; i < poll_num; pfd++, psk++, i++)
+  {
+    int e = 1;
+
+    if (! pfd->revents)
+      continue;
+
+    if (pfd->revents & POLLNVAL)
+      die("poll: invalid fd %d", pfd->fd);
+
+    if (pfd->revents & POLLIN)
+      while (e && *psk && (*psk)->rx_hook)
+	e = sk_read(*psk, pfd->revents);
+
+    e = 1;
+    if (pfd->revents & POLLOUT)
+    {
+      loop->poll_changed = 1;
+      while (e && *psk)
+	e = sk_write(*psk);
+    }
+  }
+}
+
+
+/*
+ *	Birdloop
+ */
+
+struct birdloop main_birdloop;
+
+static void birdloop_enter_locked(struct birdloop *loop);
+
+void
+birdloop_init(void)
+{
+  wakeup_init(&main_birdloop);
+
+  main_birdloop.time.domain = the_bird_domain.the_bird;
+  main_birdloop.time.loop = &main_birdloop;
+
+  times_update();
+  timers_init(&main_birdloop.time, &root_pool);
+
+  birdloop_enter_locked(&main_birdloop);
+}
+
+static void *birdloop_main(void *arg);
+
+struct birdloop *
+birdloop_new(pool *pp, uint order, const char *name)
+{
+  struct domain_generic *dg = domain_new(name, order);
+
+  pool *p = rp_new(pp, name);
+  struct birdloop *loop = mb_allocz(p, sizeof(struct birdloop));
+  loop->pool = p;
+
+  loop->time.domain = dg;
+  loop->time.loop = loop;
+
+  birdloop_enter(loop);
+
+  wakeup_init(loop);
+  ev_init_list(&loop->event_list, loop, name);
+  timers_init(&loop->time, p);
+  sockets_init(loop);
+
+  int e = 0;
+
+  if (e = pthread_attr_init(&loop->thread_attr))
+    die("pthread_attr_init() failed: %M", e);
+
+  if (e = pthread_attr_setstacksize(&loop->thread_attr, THREAD_STACK_SIZE))
+    die("pthread_attr_setstacksize(%u) failed: %M", THREAD_STACK_SIZE, e);
+
+  if (e = pthread_attr_setdetachstate(&loop->thread_attr, PTHREAD_CREATE_DETACHED))
+    die("pthread_attr_setdetachstate(PTHREAD_CREATE_DETACHED) failed: %M", e);
+
+  if (e = pthread_create(&loop->thread_id, &loop->thread_attr, birdloop_main, loop))
+    die("pthread_create() failed: %M", e);
+
+  birdloop_leave(loop);
+
+  return loop;
+}
+
+static void
+birdloop_do_stop(struct birdloop *loop, void (*stopped)(void *data), void *data)
+{
+  loop->stopped = stopped;
+  loop->stop_data = data;
+  wakeup_do_kick(loop);
+}
+
+void
+birdloop_stop(struct birdloop *loop, void (*stopped)(void *data), void *data)
+{
+  DG_LOCK(loop->time.domain);
+  birdloop_do_stop(loop, stopped, data);
+  DG_UNLOCK(loop->time.domain);
+}
+
+void
+birdloop_stop_self(struct birdloop *loop, void (*stopped)(void *data), void *data)
+{
+  ASSERT_DIE(loop == birdloop_current);
+  ASSERT_DIE(DG_IS_LOCKED(loop->time.domain));
+
+  birdloop_do_stop(loop, stopped, data);
+}
+
+void
+birdloop_free(struct birdloop *loop)
+{
+  ASSERT_DIE(loop->links == 0);
+  ASSERT_DIE(pthread_equal(pthread_self(), loop->thread_id));
+
+  rcu_birdloop_stop(&loop->rcu);
+  pthread_attr_destroy(&loop->thread_attr);
+
+  domain_free(loop->time.domain);
+  rfree(loop->pool);
+}
+
+static void
+birdloop_enter_locked(struct birdloop *loop)
+{
+  ASSERT_DIE(DG_IS_LOCKED(loop->time.domain));
+  ASSERT_DIE(!birdloop_inside(loop));
+
+  /* Store the old context */
+  loop->prev_loop = birdloop_current;
+
+  /* Put the new context */
+  birdloop_current = loop;
+}
+
+void
+birdloop_enter(struct birdloop *loop)
+{
+  DG_LOCK(loop->time.domain);
+  return birdloop_enter_locked(loop);
+}
+
+static void
+birdloop_leave_locked(struct birdloop *loop)
+{
+  /* Check the current context */
+  ASSERT_DIE(birdloop_current == loop);
+
+  /* Send pending pings */
+  if (loop->ping_pending)
+  {
+    loop->ping_pending = 0;
+    birdloop_do_ping(loop);
+  }
+
+  /* Restore the old context */
+  birdloop_current = loop->prev_loop;
+}
+
+void
+birdloop_leave(struct birdloop *loop)
+{
+  birdloop_leave_locked(loop);
+  DG_UNLOCK(loop->time.domain);
+}
+
+void
+birdloop_mask_wakeups(struct birdloop *loop)
+{
+  ASSERT_DIE(birdloop_wakeup_masked == NULL);
+  birdloop_wakeup_masked = loop;
+}
+
+void
+birdloop_unmask_wakeups(struct birdloop *loop)
+{
+  ASSERT_DIE(birdloop_wakeup_masked == loop);
+  birdloop_wakeup_masked = NULL;
+  if (birdloop_wakeup_masked_count)
+    wakeup_do_kick(loop);
+
+  birdloop_wakeup_masked_count = 0;
+}
+
+void
+birdloop_link(struct birdloop *loop)
+{
+  ASSERT_DIE(birdloop_inside(loop));
+  loop->links++;
+}
+
+void
+birdloop_unlink(struct birdloop *loop)
+{
+  ASSERT_DIE(birdloop_inside(loop));
+  loop->links--;
+}
+
+static void *
+birdloop_main(void *arg)
+{
+  struct birdloop *loop = arg;
+  timer *t;
+  int rv, timeout;
+
+  rcu_birdloop_start(&loop->rcu);
+
+  btime loop_begin = current_time();
+
+  tmp_init(loop->pool);
+
+  birdloop_enter(loop);
+  while (1)
+  {
+    timers_fire(&loop->time, 0);
+    if (ev_run_list(&loop->event_list))
+      timeout = 0;
+    else if (t = timers_first(&loop->time))
+      timeout = (tm_remains(t) TO_MS) + 1;
+    else
+      timeout = -1;
+
+    if (loop->poll_changed)
+      sockets_prepare(loop);
+
+    btime duration = current_time() - loop_begin;
+    if (duration > config->watchdog_warning)
+      log(L_WARN "I/O loop cycle took %d ms", (int) (duration TO_MS));
+
+    birdloop_leave(loop);
+
+  try:
+    rv = poll(loop->poll_fd.data, loop->poll_fd.used, timeout);
+    if (rv < 0)
+    {
+      if (errno == EINTR || errno == EAGAIN)
+	goto try;
+      die("poll: %m");
+    }
+
+    birdloop_enter(loop);
+
+    if (loop->close_scheduled)
+      sockets_close_fds(loop);
+
+    if (loop->stopped)
+      break;
+
+    loop_begin = current_time();
+
+    if (rv)
+      sockets_fire(loop);
+
+    atomic_exchange_explicit(&loop->ping_sent, 0, memory_order_acq_rel);
+  }
+
+  /* Flush remaining events */
+  ASSERT_DIE(!ev_run_list(&loop->event_list));
+
+  /* No timers allowed */
+  ASSERT_DIE(timers_count(&loop->time) == 0);
+  ASSERT_DIE(EMPTY_LIST(loop->sock_list));
+  ASSERT_DIE(loop->sock_num == 0);
+
+  birdloop_leave(loop);
+  loop->stopped(loop->stop_data);
+
+  return NULL;
+}
+
+void
+birdloop_yield(void)
+{
+  usleep(100);
+}
diff --git a/sysdep/unix/io-loop.h b/sysdep/unix/io-loop.h
new file mode 100644
index 00000000..31c40459
--- /dev/null
+++ b/sysdep/unix/io-loop.h
@@ -0,0 +1,43 @@
+/*
+ *	BIRD -- I/O and event loop
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_SYSDEP_UNIX_IO_LOOP_H_
+#define _BIRD_SYSDEP_UNIX_IO_LOOP_H_
+
+#include "lib/rcu.h"
+
+struct birdloop
+{
+  pool *pool;
+
+  struct timeloop time;
+  event_list event_list;
+  list sock_list;
+  uint sock_num;
+
+  BUFFER(sock *) poll_sk;
+  BUFFER(struct pollfd) poll_fd;
+  u8 poll_changed;
+  u8 close_scheduled;
+
+  uint ping_pending;
+  _Atomic u32 ping_sent;
+  int wakeup_fds[2];
+
+  pthread_t thread_id;
+  pthread_attr_t thread_attr;
+
+  struct rcu_birdloop rcu;
+
+  uint links;
+
+  void (*stopped)(void *data);
+  void *stop_data;
+
+  struct birdloop *prev_loop;
+};
+
+#endif
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 8a116789..23baffb2 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -36,12 +36,14 @@
 #include "lib/resource.h"
 #include "lib/socket.h"
 #include "lib/event.h"
+#include "lib/locking.h"
 #include "lib/timer.h"
 #include "lib/string.h"
 #include "nest/iface.h"
 #include "conf/conf.h"
 
 #include "sysdep/unix/unix.h"
+#include "sysdep/unix/io-loop.h"
 #include CONFIG_INCLUDE_SYSIO_H
 
 /* Maximum number of calls of tx handler for one socket in one
@@ -122,55 +124,50 @@ rf_fileno(struct rfile *f)
 
 btime boot_time;
 
+
 void
-times_init(struct timeloop *loop)
+times_update(void)
 {
   struct timespec ts;
   int rv;
 
+  btime old_time = current_time();
+  btime old_real_time = current_real_time();
+
   rv = clock_gettime(CLOCK_MONOTONIC, &ts);
   if (rv < 0)
     die("Monotonic clock is missing");
 
   if ((ts.tv_sec < 0) || (((u64) ts.tv_sec) > ((u64) 1 << 40)))
     log(L_WARN "Monotonic clock is crazy");
-
-  loop->last_time = ts.tv_sec S + ts.tv_nsec NS;
-  loop->real_time = 0;
-}
-
-void
-times_update(struct timeloop *loop)
-{
-  struct timespec ts;
-  int rv;
-
-  rv = clock_gettime(CLOCK_MONOTONIC, &ts);
-  if (rv < 0)
-    die("clock_gettime: %m");
-
+  
   btime new_time = ts.tv_sec S + ts.tv_nsec NS;
 
-  if (new_time < loop->last_time)
+  if (new_time < old_time)
     log(L_ERR "Monotonic clock is broken");
 
-  loop->last_time = new_time;
-  loop->real_time = 0;
-}
-
-void
-times_update_real_time(struct timeloop *loop)
-{
-  struct timespec ts;
-  int rv;
-
   rv = clock_gettime(CLOCK_REALTIME, &ts);
   if (rv < 0)
     die("clock_gettime: %m");
 
-  loop->real_time = ts.tv_sec S + ts.tv_nsec NS;
-}
+  btime new_real_time = ts.tv_sec S + ts.tv_nsec NS;
 
+  if (!atomic_compare_exchange_strong_explicit(
+      &last_time,
+      &old_time,
+      new_time,
+      memory_order_acq_rel,
+      memory_order_relaxed))
+    DBG("Time update collision: last_time");
+
+  if (!atomic_compare_exchange_strong_explicit(
+      &real_time,
+      &old_real_time,
+      new_real_time,
+      memory_order_acq_rel,
+      memory_order_relaxed))
+    DBG("Time update collision: real_time");
+}
 
 /**
  * DOC: Sockets
@@ -804,18 +801,16 @@ sk_free(resource *r)
     sk_ssh_free(s);
 #endif
 
-  if (s->fd < 0)
+  if ((s->fd < 0) || (s->flags & SKF_THREAD))
     return;
 
-  /* FIXME: we should call sk_stop() for SKF_THREAD sockets */
-  if (!(s->flags & SKF_THREAD))
-  {
-    if (s == current_sock)
-      current_sock = sk_next(s);
-    if (s == stored_sock)
-      stored_sock = sk_next(s);
+  if (s == current_sock)
+    current_sock = sk_next(s);
+  if (s == stored_sock)
+    stored_sock = sk_next(s);
+
+  if (enlisted(&s->n))
     rem_node(&s->n);
-  }
 
   if (s->type != SK_SSH && s->type != SK_SSH_ACTIVE)
     close(s->fd);
@@ -1108,7 +1103,11 @@ sk_passive_connected(sock *s, int type)
     return 1;
   }
 
-  sk_insert(t);
+  if (s->flags & SKF_PASSIVE_THREAD)
+    t->flags |= SKF_THREAD;
+  else
+    sk_insert(t);
+
   sk_alloc_bufs(t);
   s->rx_hook(t, 0);
   return 1;
@@ -1516,6 +1515,36 @@ sk_open_unix(sock *s, char *name)
   return 0;
 }
 
+static void
+sk_reloop_hook(void *_vs)
+{
+  sock *s = _vs;
+  if (birdloop_inside(&main_birdloop))
+  {
+    s->flags &= ~SKF_THREAD;
+    sk_insert(s);
+  }
+  else
+  {
+    s->flags |= SKF_THREAD;
+    sk_start(s);
+  }
+}
+
+void
+sk_reloop(sock *s, struct birdloop *loop)
+{
+  if (enlisted(&s->n))
+    rem_node(&s->n);
+
+  s->reloop = (event) {
+    .hook = sk_reloop_hook,
+    .data = s,
+  };
+
+  ev_send_loop(loop, &s->reloop);
+}
+
 
 #define CMSG_RX_SPACE MAX(CMSG4_SPACE_PKTINFO+CMSG4_SPACE_TTL, \
 			  CMSG6_SPACE_PKTINFO+CMSG6_SPACE_TTL)
@@ -2037,34 +2066,21 @@ struct event_log_entry
 static struct event_log_entry event_log[EVENT_LOG_LENGTH];
 static struct event_log_entry *event_open;
 static int event_log_pos, event_log_num, watchdog_active;
-static btime last_time;
+static btime last_io_time;
 static btime loop_time;
 
 static void
 io_update_time(void)
 {
-  struct timespec ts;
-  int rv;
-
-  /*
-   * This is third time-tracking procedure (after update_times() above and
-   * times_update() in BFD), dedicated to internal event log and latency
-   * tracking. Hopefully, we consolidate these sometimes.
-   */
-
-  rv = clock_gettime(CLOCK_MONOTONIC, &ts);
-  if (rv < 0)
-    die("clock_gettime: %m");
-
-  last_time = ts.tv_sec S + ts.tv_nsec NS;
+  last_io_time = current_time();
 
   if (event_open)
   {
-    event_open->duration = last_time - event_open->timestamp;
+    event_open->duration = last_io_time - event_open->timestamp;
 
     if (event_open->duration > config->latency_limit)
-      log(L_WARN "Event 0x%p 0x%p took %d ms",
-	  event_open->hook, event_open->data, (int) (event_open->duration TO_MS));
+      log(L_WARN "Event 0x%p 0x%p took %u.%03u ms",
+	  event_open->hook, event_open->data, (uint) (event_open->duration TO_MS), (uint) (event_open->duration % 1000));
 
     event_open = NULL;
   }
@@ -2089,7 +2105,7 @@ io_log_event(void *hook, void *data)
 
   en->hook = hook;
   en->data = data;
-  en->timestamp = last_time;
+  en->timestamp = last_io_time;
   en->duration = 0;
 
   event_log_num++;
@@ -2117,14 +2133,14 @@ io_log_dump(void)
     struct event_log_entry *en = event_log + (event_log_pos + i) % EVENT_LOG_LENGTH;
     if (en->hook)
       log(L_DEBUG "  Event 0x%p 0x%p at %8d for %d ms", en->hook, en->data,
-	  (int) ((last_time - en->timestamp) TO_MS), (int) (en->duration TO_MS));
+	  (int) ((last_io_time - en->timestamp) TO_MS), (int) (en->duration TO_MS));
   }
 }
 
 void
 watchdog_sigalrm(int sig UNUSED)
 {
-  /* Update last_time and duration, but skip latency check */
+  /* Update last_io_time and duration, but skip latency check */
   config->latency_limit = 0xffffffff;
   io_update_time();
 
@@ -2137,7 +2153,7 @@ watchdog_start1(void)
 {
   io_update_time();
 
-  loop_time = last_time;
+  loop_time = last_io_time;
 }
 
 static inline void
@@ -2145,7 +2161,7 @@ watchdog_start(void)
 {
   io_update_time();
 
-  loop_time = last_time;
+  loop_time = last_io_time;
   event_log_num = 0;
 
   if (config->watchdog_timeout)
@@ -2166,10 +2182,10 @@ watchdog_stop(void)
     watchdog_active = 0;
   }
 
-  btime duration = last_time - loop_time;
+  btime duration = last_io_time - loop_time;
   if (duration > config->watchdog_warning)
-    log(L_WARN "I/O loop cycle took %d ms for %d events",
-	(int) (duration TO_MS), event_log_num);
+    log(L_WARN "I/O loop cycle took %u.%03u ms for %d events",
+	(uint) (duration TO_MS), (uint) (duration % 1000), event_log_num);
 }
 
 
@@ -2181,8 +2197,9 @@ void
 io_init(void)
 {
   init_list(&sock_list);
-  init_list(&global_event_list);
-  init_list(&global_work_list);
+  ev_init_list(&global_event_list, &main_birdloop, "Global event list");
+  ev_init_list(&global_work_list, &main_birdloop, "Global work list");
+  ev_init_list(&main_birdloop.event_list, &main_birdloop, "Global fast event list");
   krt_io_init();
   // XXX init_times();
   // XXX update_times();
@@ -2196,6 +2213,8 @@ static int short_loops = 0;
 #define SHORT_LOOP_MAX 10
 #define WORK_EVENTS_MAX 10
 
+void pipe_drain(int fd);
+
 void
 io_loop(void)
 {
@@ -2210,22 +2229,28 @@ io_loop(void)
   watchdog_start1();
   for(;;)
     {
-      times_update(&main_timeloop);
+      times_update();
       events = ev_run_list(&global_event_list);
       events = ev_run_list_limited(&global_work_list, WORK_EVENTS_MAX) || events;
-      timers_fire(&main_timeloop);
+      events = ev_run_list(&main_birdloop.event_list) || events;
+      timers_fire(&main_birdloop.time, 1);
       io_close_event();
 
       // FIXME
       poll_tout = (events ? 0 : 3000); /* Time in milliseconds */
-      if (t = timers_first(&main_timeloop))
+      if (t = timers_first(&main_birdloop.time))
       {
-	times_update(&main_timeloop);
+	times_update();
 	timeout = (tm_remains(t) TO_MS) + 1;
 	poll_tout = MIN(poll_tout, timeout);
       }
 
-      nfds = 0;
+      /* A hack to reload main io_loop() when something has changed asynchronously. */
+      pfd[0].fd = main_birdloop.wakeup_fds[0];
+      pfd[0].events = POLLIN;
+
+      nfds = 1;
+
       WALK_LIST(n, sock_list)
 	{
 	  pfd[nfds] = (struct pollfd) { .fd = -1 }; /* everything other set to 0 by this */
@@ -2284,7 +2309,9 @@ io_loop(void)
 
       /* And finally enter poll() to find active sockets */
       watchdog_stop();
+      birdloop_leave(&main_birdloop);
       pout = poll(pfd, nfds, poll_tout);
+      birdloop_enter(&main_birdloop);
       watchdog_start();
 
       if (pout < 0)
@@ -2295,7 +2322,15 @@ io_loop(void)
 	}
       if (pout)
 	{
-	  times_update(&main_timeloop);
+	  if (pfd[0].revents & POLLIN)
+	  {
+	    /* IO loop reload requested */
+	    pipe_drain(main_birdloop.wakeup_fds[0]);
+	    atomic_exchange_explicit(&main_birdloop.ping_sent, 0, memory_order_acq_rel);
+	    continue;
+	  }
+
+	  times_update();
 
 	  /* guaranteed to be non-empty */
 	  current_sock = SKIP_BACK(sock, n, HEAD(sock_list));
diff --git a/sysdep/unix/krt.c b/sysdep/unix/krt.c
index 93d19614..dd2c63c4 100644
--- a/sysdep/unix/krt.c
+++ b/sysdep/unix/krt.c
@@ -681,9 +681,9 @@ krt_scan_timer_kick(struct krt_proto *p)
  */
 
 static int
-krt_preexport(struct channel *c, rte *e)
+krt_preexport(struct channel *C, rte *e)
 {
-  if (e->src->proto == c->proto)
+  if (e->src->proto == C->proto)
     return -1;
 
   if (!krt_capable(e))
diff --git a/sysdep/unix/log.c b/sysdep/unix/log.c
index 4e9df069..185231e8 100644
--- a/sysdep/unix/log.c
+++ b/sysdep/unix/log.c
@@ -15,6 +15,7 @@
  * user's manual.
  */
 
+#include <stdatomic.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -35,8 +36,10 @@ static FILE *dbgf;
 static list *current_log_list;
 static char *current_syslog_name; /* NULL -> syslog closed */
 
+static _Atomic uint max_thread_id = ATOMIC_VAR_INIT(1);
+static _Thread_local uint this_thread_id;
 
-#ifdef USE_PTHREADS
+#define THIS_THREAD_ID  (this_thread_id ?: (this_thread_id = atomic_fetch_add_explicit(&max_thread_id, 1, memory_order_acq_rel)))
 
 #include <pthread.h>
 
@@ -48,15 +51,6 @@ static pthread_t main_thread;
 void main_thread_init(void) { main_thread = pthread_self(); }
 static int main_thread_self(void) { return pthread_equal(pthread_self(), main_thread); }
 
-#else
-
-static inline void log_lock(void) {  }
-static inline void log_unlock(void) {  }
-void main_thread_init(void) { }
-static int main_thread_self(void) { return 1; }
-
-#endif
-
 
 #ifdef HAVE_SYSLOG_H
 #include <sys/syslog.h>
@@ -189,7 +183,7 @@ log_commit(int class, buffer *buf)
 		l->pos += msg_len;
 	      }
 
-	      fprintf(l->fh, "%s <%s> ", tbuf, class_names[class]);
+	      fprintf(l->fh, "%s [%04x] <%s> ", tbuf, THIS_THREAD_ID, class_names[class]);
 	    }
 	  fputs(buf->start, l->fh);
 	  fputc('\n', l->fh);
@@ -299,6 +293,8 @@ die(const char *msg, ...)
   exit(1);
 }
 
+static struct timespec dbg_time_start;
+
 /**
  * debug - write to debug output
  * @msg: a printf-like message
@@ -311,12 +307,33 @@ debug(const char *msg, ...)
 {
 #define MAX_DEBUG_BUFSIZE 16384
   va_list args;
-  char buf[MAX_DEBUG_BUFSIZE];
+  char buf[MAX_DEBUG_BUFSIZE], *pos = buf;
+  int max = MAX_DEBUG_BUFSIZE;
 
   va_start(args, msg);
   if (dbgf)
     {
-      if (bvsnprintf(buf, MAX_DEBUG_BUFSIZE, msg, args) < 0)
+      struct timespec dbg_time;
+      clock_gettime(CLOCK_MONOTONIC, &dbg_time);
+      uint nsec;
+      uint sec;
+
+      if (dbg_time.tv_nsec > dbg_time_start.tv_nsec)
+      {
+	nsec = dbg_time.tv_nsec - dbg_time_start.tv_nsec;
+	sec = dbg_time.tv_sec - dbg_time_start.tv_sec;
+      }
+      else
+      {
+	nsec = 1000000000 + dbg_time.tv_nsec - dbg_time_start.tv_nsec;
+	sec = dbg_time.tv_sec - dbg_time_start.tv_sec - 1;
+      }
+
+      int n = bsnprintf(pos, max, "%u.%09u: [%04x] ", sec, nsec, THIS_THREAD_ID);
+      pos += n;
+      max -= n;
+
+      if (bvsnprintf(pos, max, msg, args) < 0)
 	bug("Extremely long debug output, split it.");
 
       fputs(buf, dbgf);
@@ -422,6 +439,8 @@ done:
 void
 log_init_debug(char *f)
 {
+  clock_gettime(CLOCK_MONOTONIC, &dbg_time_start);
+
   if (dbgf && dbgf != stderr)
     fclose(dbgf);
   if (!f)
diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c
index fd4934d9..bf9f2be0 100644
--- a/sysdep/unix/main.c
+++ b/sysdep/unix/main.c
@@ -28,6 +28,7 @@
 #include "lib/resource.h"
 #include "lib/socket.h"
 #include "lib/event.h"
+#include "lib/locking.h"
 #include "lib/timer.h"
 #include "lib/string.h"
 #include "nest/rt.h"
@@ -116,7 +117,7 @@ add_num_const(char *name, int val, const char *file, const uint line)
   struct f_val *v = cfg_alloc(sizeof(struct f_val));
   *v = (struct f_val) { .type = T_INT, .val.i = val };
   struct symbol *sym = cf_get_symbol(name);
-  if (sym->class && (sym->scope == conf_this_scope))
+  if (sym->class && cf_symbol_is_local(sym))
     cf_error("Error reading value for %s from %s:%d: already defined", name, file, line);
 
   cf_define_symbol(sym, SYM_CONSTANT | T_INT, val, v);
@@ -873,13 +874,16 @@ main(int argc, char **argv)
     dmalloc_debug(0x2f03d00);
 #endif
 
+  times_update();
   parse_args(argc, argv);
   log_switch(1, NULL, NULL);
 
+  the_bird_lock();
+
   random_init();
   net_init();
   resource_init();
-  timer_init();
+  birdloop_init();
   olock_init();
   rt_init();
   io_init();
@@ -927,6 +931,7 @@ main(int argc, char **argv)
       dup2(0, 2);
     }
 
+
   main_thread_init();
 
   write_pid_file();