diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
new file mode 100644
index 00000000..fa6b5b28
--- /dev/null
+++ b/sysdep/unix/io.c
@@ -0,0 +1,739 @@
+/*
+ *	BIRD Internet Routing Daemon -- Unix I/O
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "nest/bird.h"
+#include "lib/lists.h"
+#include "lib/resource.h"
+#include "lib/timer.h"
+#include "lib/socket.h"
+#include "nest/iface.h"
+
+#include "lib/unix.h"
+
+/*
+ *	Timers
+ */
+
+#define NEAR_TIMER_LIMIT 4
+
+#ifdef TIME_T_IS_64BIT
+#define TIME_INFINITY 0x7fffffffffffffff
+#else
+#ifdef TIME_T_IS_SIGNED
+#define TIME_INFINITY 0x7fffffff
+#else
+#define TIME_INFINITY 0xffffffff
+#endif
+#endif
+
+static list near_timers, far_timers;
+static bird_clock_t first_far_timer = TIME_INFINITY;
+
+bird_clock_t now;
+
+static void
+tm_free(resource *r)
+{
+  timer *t = (timer *) r;
+
+  tm_stop(t);
+}
+
+static void
+tm_dump(resource *r)
+{
+  timer *t = (timer *) r;
+
+  debug("(code %p, data %p, ");
+  if (t->expires)
+    debug("expires in %d sec)\n", t->expires - now);
+  else
+    debug("inactive)\n");
+}
+
+static struct resclass tm_class = {
+  "Timer",
+  sizeof(timer),
+  tm_free,
+  tm_dump
+};
+
+timer *
+tm_new(pool *p)
+{
+  timer *t = ralloc(p, &tm_class);
+  t->hook = NULL;
+  t->data = NULL;
+  t->randomize = 0;
+  t->expires = 0;
+  return t;
+}
+
+static inline void
+tm_insert_near(timer *t)
+{
+  node *n = HEAD(near_timers);
+
+  while (n->next && (SKIP_BACK(timer, n, n)->expires < t->expires))
+    n = n->next;
+  insert_node(&t->n, n->prev);
+}
+
+void
+tm_start(timer *t, unsigned after)
+{
+  bird_clock_t when;
+
+  if (t->randomize)
+    after += random() % t->randomize;
+  when = now + after;
+  if (t->expires == when)
+    return;
+  if (t->expires)
+    rem_node(&t->n);
+  t->expires = when;
+  if (after <= NEAR_TIMER_LIMIT)
+    tm_insert_near(t);
+  else
+    {
+      if (!first_far_timer || first_far_timer > when)
+	first_far_timer = when;
+      add_tail(&far_timers, &t->n);
+    }
+}
+
+void
+tm_stop(timer *t)
+{
+  if (t->expires)
+    {
+      rem_node(&t->n);
+      t->expires = 0;
+    }
+}
+
+static void
+tm_dump_them(char *name, list *l)
+{
+  node *n;
+  timer *t;
+
+  debug("%s timers:\n", name);
+  WALK_LIST(n, *l)
+    {
+      t = SKIP_BACK(timer, n, n);
+      debug("%p ", t);
+      tm_dump(&t->r);
+    }
+  debug("\n");
+}
+
+void
+tm_dump_all(void)
+{
+  tm_dump_them("Near", &near_timers);
+  tm_dump_them("Far", &far_timers);
+}
+
+static inline time_t
+tm_first_shot(void)
+{
+  time_t x = first_far_timer;
+
+  if (!EMPTY_LIST(near_timers))
+    {
+      timer *t = SKIP_BACK(timer, n, HEAD(near_timers));
+      if (t->expires < x)
+	x = t->expires;
+    }
+  return x;
+}
+
+static void
+tm_shot(void)
+{
+  timer *t;
+  node *n, *m;
+
+  if (first_far_timer <= now)
+    {
+      clock_t limit = now + NEAR_TIMER_LIMIT;
+      first_far_timer = TIME_INFINITY;
+      n = HEAD(far_timers);
+      while (m = n->next)
+	{
+	  t = SKIP_BACK(timer, n, n);
+	  if (t->expires <= limit)
+	    {
+	      rem_node(n);
+	      tm_insert_near(t);
+	    }
+	  else if (t->expires < first_far_timer)
+	    first_far_timer = t->expires;
+	  n = m;
+	}
+    }
+  while ((n = HEAD(near_timers)) -> next)
+    {
+      t = SKIP_BACK(timer, n, n);
+      if (t->expires > now)
+	break;
+      rem_node(n);
+      t->expires = 0;
+      t->hook(t);
+    }
+}
+
+/*
+ *	Sockets
+ */
+
+static list sock_list;
+
+static void
+sk_free(resource *r)
+{
+  sock *s = (sock *) r;
+
+  if (s->fd >= 0)
+    rem_node(&s->n);
+}
+
+static void
+sk_dump(resource *r)
+{
+  sock *s = (sock *) r;
+  static char *sk_type_names[] = { "TCP<", "TCP>", "TCP", "UDP", "UDP/MC", "IP", "IP/MC" };
+
+  debug("(%s, ud=%p, sa=%08x, sp=%d, da=%08x, dp=%d, tos=%d, ttl=%d, if=%s)\n",
+	sk_type_names[s->type],
+	s->data,
+	s->saddr,
+	s->sport,
+	s->daddr,
+	s->dport,
+	s->tos,
+	s->ttl,
+	s->iface ? s->iface->name : "none");
+}
+
+static struct resclass sk_class = {
+  "Socket",
+  sizeof(sock),
+  sk_free,
+  sk_dump
+};
+
+sock *
+sk_new(pool *p)
+{
+  sock *s = ralloc(p, &sk_class);
+  s->pool = p;
+  s->data = NULL;
+  s->saddr = s->daddr = IPA_NONE;
+  s->sport = s->dport = 0;
+  s->tos = s->ttl = -1;
+  s->iface = NULL;
+  s->rbuf = NULL;
+  s->rx_hook = NULL;
+  s->rbsize = 0;
+  s->tbuf = NULL;
+  s->tx_hook = NULL;
+  s->tbsize = 0;
+  s->err_hook = NULL;
+  s->fd = -1;
+  return s;
+}
+
+#define ERR(x) do { err = x; goto bad; } while(0)
+
+static inline void
+set_inaddr(struct in_addr *ia, ip_addr a)
+{
+  a = ipa_hton(a);
+  memcpy(&ia->s_addr, &a, sizeof(a));
+}
+
+static void
+fill_in_sockaddr(struct sockaddr_in *sa, ip_addr a, unsigned port)
+{
+  sa->sin_family = AF_INET;
+  sa->sin_port = htons(port);
+  set_inaddr(&sa->sin_addr, a);
+}
+
+static void
+get_sockaddr(struct sockaddr_in *sa, ip_addr *a, unsigned *port)
+{
+  *port = ntohs(sa->sin_port);
+  memcpy(a, &sa->sin_addr.s_addr, sizeof(*a));
+  *a = ipa_ntoh(*a);
+}
+
+static char *
+sk_setup(sock *s)
+{
+  int fd = s->fd;
+  int one = 1;
+  char *err;
+
+  if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
+    ERR("fcntl(O_NONBLOCK)");
+  if ((s->tos >= 0) && setsockopt(fd, SOL_IP, IP_TOS, &s->tos, sizeof(s->tos)) < 0)
+    ERR("IP_TOS");
+  if (s->ttl >= 0)
+    {
+      if (setsockopt(fd, SOL_IP, IP_TTL, &s->ttl, sizeof(s->ttl)) < 0)
+	ERR("IP_TTL");
+      if (setsockopt(fd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0)
+	ERR("SO_DONTROUTE");
+    }
+#ifdef IP_PMTUDISC
+  if (s->type != SK_TCP_PASSIVE && s->type != SK_TCP_ACTIVE)
+    {
+      int dont = IP_PMTUDISC_DONT;
+      if (setsockopt(fd, SOL_IP, IP_PMTUDISC, &dont, sizeof(dont)) < 0)
+	ERR("IP_PMTUDISC");
+    }
+#endif
+  /* FIXME: Set send/receive buffers? */
+  /* FIXME: Set keepalive for TCP connections? */
+  err = NULL;
+bad:
+  return err;
+}
+
+static void
+sk_alloc_bufs(sock *s)
+{
+  if (!s->rbuf && s->rbsize)
+    s->rbuf = mb_alloc(s->pool, s->rbsize);
+  s->rpos = s->rbuf;
+  if (!s->tbuf && s->tbsize)
+    s->tbuf = mb_alloc(s->pool, s->tbsize);
+  s->tpos = s->ttx = s->tbuf;
+}
+
+void
+sk_tcp_connected(sock *s)
+{
+  s->rx_hook(s, 0);
+  s->type = SK_TCP;
+  sk_alloc_bufs(s);
+}
+
+int
+sk_open(sock *s)
+{
+  int fd, e;
+  struct sockaddr_in sa;
+  int zero = 0;
+  int one = 1;
+  int type = s->type;
+  int has_src = ipa_nonzero(s->saddr) || s->sport;
+  int has_dest = ipa_nonzero(s->daddr);
+  char *err;
+
+  switch (type)
+    {
+    case SK_TCP_ACTIVE:
+    case SK_TCP_PASSIVE:
+      fd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+      break;
+    case SK_UDP:
+    case SK_UDP_MC:
+      fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+      break;
+    case SK_IP:
+    case SK_IP_MC:
+      fd = socket(PF_INET, SOCK_RAW, s->dport);
+      break;
+    default:
+      die("sk_open() called for invalid sock type %d", s->type);
+    }
+  if (fd < 0)
+    die("sk_open: socket: %m");
+  s->fd = fd;
+
+  if (err = sk_setup(s))
+    goto bad;
+  switch (type)
+    {
+    case SK_UDP:
+    case SK_IP:
+      if (s->iface)			/* It's a broadcast socket */
+	if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one)) < 0)
+	  ERR("SO_BROADCAST");
+      break;
+    case SK_UDP_MC:
+    case SK_IP_MC:
+      {
+#ifdef HAVE_IP_MREQN
+	struct ip_mreqn mreq;
+	mreq.imr_ifindex = s->iface->index;
+	if (has_src)
+	  set_inaddr(&mreq.imr_address, s->saddr);
+	else
+	  set_inaddr(&mreq.imr_address, s->iface->ifa->ip);
+#else
+	struct ip_mreq mreq;
+	if (has_src)
+	  set_inaddr(&mreq.imr_interface, s->saddr);
+	else
+	  set_inaddr(&mreq.imr_interface, s->iface->ifa->ip);
+#endif
+	set_inaddr(&mreq.imr_multiaddr, s->daddr);
+	if (has_dest)
+	  {
+	    if (
+#ifdef IP_DEFAULT_MULTICAST_TTL
+		s->ttl != IP_DEFAULT_MULTICAST_TTL &&
+#endif
+		setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &s->ttl, sizeof(s->ttl)) < 0)
+	      ERR("IP_MULTICAST_TTL");
+	    if (
+#ifdef IP_DEFAULT_MULTICAST_LOOP
+		IP_DEFAULT_MULTICAST_LOOP &&
+#endif
+		setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &zero, sizeof(zero)) < 0)
+	      ERR("IP_MULTICAST_LOOP");
+	    if (setsockopt(fd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) < 0)
+	      ERR("IP_MULTICAST_IF");
+	}
+      if (has_src && setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
+	ERR("IP_ADD_MEMBERSHIP");
+      break;
+      }
+    }
+  if (has_src)
+    {
+      int port;
+
+      if (type == SK_IP || type == SK_IP_MC)
+	port = 0;
+      else
+	{
+	  port = s->sport;
+	  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
+	    ERR("SO_REUSEADDR");
+	}
+      fill_in_sockaddr(&sa, s->saddr, port);
+      if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
+	ERR("bind");
+    }
+  fill_in_sockaddr(&sa, s->daddr, s->dport);
+  switch (type)
+    {
+    case SK_TCP_ACTIVE:
+      if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) >= 0)
+	sk_tcp_connected(s);
+      else if (errno != EINTR && errno != EAGAIN)
+	ERR("connect");
+      break;
+    case SK_TCP_PASSIVE:
+      if (listen(fd, 8))
+	ERR("listen");
+      break;
+    }
+
+  sk_alloc_bufs(s);
+  add_tail(&sock_list, &s->n);
+  return 0;
+
+bad:
+  log(L_ERR "sk_open: %s: %m", err);
+  close(fd);
+  s->fd = -1;
+  return -1;
+}
+
+static int
+sk_maybe_write(sock *s)
+{
+  int e;
+
+  switch (s->type)
+    {
+    case SK_TCP:
+      while (s->ttx != s->tpos)
+	{
+	  e = write(s->fd, s->ttx, s->tpos - s->ttx);
+	  if (e < 0)
+	    {
+	      if (errno != EINTR && errno != EAGAIN)
+		{
+		  log(L_ERR "write: %m");
+		  s->err_hook(s, errno);
+		  return -1;
+		}
+	      return 0;
+	    }
+	  s->ttx += e;
+	}
+      s->ttx = s->tpos = s->tbuf;
+      return 1;
+    case SK_UDP:
+    case SK_UDP_MC:
+    case SK_IP:
+    case SK_IP_MC:
+      {
+	struct sockaddr_in sa;
+
+	if (s->tbuf == s->tpos)
+	  return 1;
+	fill_in_sockaddr(&sa, s->faddr, s->fport);
+	e = sendto(s->fd, s->tbuf, s->tpos - s->tbuf, 0, (struct sockaddr *) &sa, sizeof(sa));
+	if (e < 0)
+	  {
+	    if (errno != EINTR && errno != EAGAIN)
+	      {
+		log(L_ERR "sendto: %m");
+		s->err_hook(s, errno);
+		return -1;
+	      }
+	    return 0;
+	  }
+	s->tpos = s->tbuf;
+	return 1;
+      }
+    default:
+      die("sk_maybe_write: unknown socket type %d", s->type);
+    }
+}
+
+int
+sk_send(sock *s, unsigned len)
+{
+  s->faddr = s->daddr;
+  s->fport = s->dport;
+  s->ttx = s->tbuf;
+  s->tpos = s->tbuf + len;
+  return sk_maybe_write(s);
+}
+
+int
+sk_send_to(sock *s, unsigned len, ip_addr addr, unsigned port)
+{
+  s->faddr = addr;
+  s->fport = port;
+  s->ttx = s->tbuf;
+  s->tpos = s->tbuf + len;
+  return sk_maybe_write(s);
+}
+
+static int
+sk_read(sock *s)
+{
+  switch (s->type)
+    {
+    case SK_TCP_ACTIVE:
+      {
+	struct sockaddr_in sa;
+	fill_in_sockaddr(&sa, s->daddr, s->dport);
+	if (connect(s->fd, (struct sockaddr *) &sa, sizeof(sa)) >= 0)
+	  sk_tcp_connected(s);
+	else if (errno != EINTR && errno != EAGAIN)
+	  {
+	    log(L_ERR "connect: %m");
+	    s->err_hook(s, errno);
+	  }
+	return 0;
+      }
+    case SK_TCP_PASSIVE:
+      {
+	struct sockaddr_in sa;
+	int al = sizeof(sa);
+	int fd = accept(s->fd, (struct sockaddr *) &sa, &al);
+	if (fd >= 0)
+	  {
+	    sock *t = sk_new(s->pool);
+	    char *err;
+	    t->type = SK_TCP;
+	    t->fd = fd;
+	    add_tail(&sock_list, &t->n);
+	    s->rx_hook(t, 0);
+	    if (err = sk_setup(t))
+	      {
+		log(L_ERR "Incoming connection: %s: %m", err);
+		s->err_hook(s, errno);
+		return 0;
+	      }
+	    sk_alloc_bufs(t);
+	    return 1;
+	  }
+	else if (errno != EINTR && errno != EAGAIN)
+	  {
+	    log(L_ERR "accept: %m");
+	    s->err_hook(s, errno);
+	  }
+	return 0;
+      }
+    case SK_TCP:
+      {
+	int c = read(s->fd, s->rpos, s->rbuf + s->rbsize - s->rpos);
+
+	if (c < 0)
+	  {
+	    if (errno != EINTR && errno != EAGAIN)
+	      {
+		log(L_ERR "read: %m");
+		s->err_hook(s, errno);
+	      }
+	  }
+	else if (!c)
+	  s->err_hook(s, 0);
+	else
+	  {
+	    s->rpos += c;
+	    if (s->rx_hook(s, s->rpos - s->rbuf))
+	      s->rpos = s->rbuf;
+	    return 1;
+	  }
+	return 0;
+      }
+    default:
+      {
+	struct sockaddr_in sa;
+	int al = sizeof(sa);
+	int e = recvfrom(s->fd, s->rbuf, s->rbsize, 0, (struct sockaddr *) &sa, &al);
+
+	if (e < 0)
+	  {
+	    if (errno != EINTR && errno != EAGAIN)
+	      {
+		log(L_ERR "recvfrom: %m");
+		s->err_hook(s, errno);
+	      }
+	    return 0;
+	  }
+	s->rpos = s->rbuf + e;
+	get_sockaddr(&sa, &s->faddr, &s->fport);
+	s->rx_hook(s, e);
+	return 1;
+      }
+    }
+}
+
+static void
+sk_write(sock *s)
+{
+  while (s->ttx != s->tbuf && sk_maybe_write(s) > 0)
+    s->tx_hook(s);
+}
+
+void
+sk_dump_all(void)
+{
+  node *n;
+  sock *s;
+
+  debug("Open sockets:\n");
+  WALK_LIST(n, sock_list)
+    {
+      s = SKIP_BACK(sock, n, n);
+      debug("%p ", s);
+      sk_dump(&s->r);
+    }
+  debug("\n");
+}
+
+#undef ERR
+
+/*
+ *	Main I/O Loop
+ */
+
+void
+io_init(void)
+{
+  init_list(&near_timers);
+  init_list(&far_timers);
+  init_list(&sock_list);
+  now = time(NULL);
+}
+
+void
+io_loop(void)
+{
+  fd_set rd, wr;
+  struct timeval timo;
+  time_t tout;
+  int hi;
+  sock *s;
+  node *n;
+
+  /* FIXME: Use poll() if available */
+
+  FD_ZERO(&rd);
+  FD_ZERO(&wr);
+  for(;;)
+    {
+      now = time(NULL);
+      tout = tm_first_shot();
+      if (tout <= now)
+	{
+	  tm_shot();
+	  continue;
+	}
+      else
+	timo.tv_sec = tout - now;
+
+      hi = 0;
+      WALK_LIST(n, sock_list)
+	{
+	  s = SKIP_BACK(sock, n, n);
+	  if (s->rx_hook)
+	    {
+	      FD_SET(s->fd, &rd);
+	      if (s->fd > hi)
+		hi = s->fd;
+	    }
+	  if (s->tx_hook && s->ttx != s->tpos)
+	    {
+	      FD_SET(s->fd, &wr);
+	      if (s->fd > hi)
+		hi = s->fd;
+	    }
+	}
+
+      hi = select(hi+1, &rd, &wr, NULL, &timo);
+      if (hi < 0)
+	{
+	  if (errno == EINTR || errno == EAGAIN)
+	    continue;
+	  die("select: %m");
+	}
+      if (hi)
+	{
+	  WALK_LIST(n, sock_list)
+	    {
+	      s = SKIP_BACK(sock, n, n);
+	      if (FD_ISSET(s->fd, &rd))
+		{
+		  FD_CLR(s->fd, &rd);
+		  while (sk_read(s))
+		    ;
+		}
+	      if (FD_ISSET(s->fd, &wr))
+		{
+		  FD_CLR(s->fd, &wr);
+		  sk_write(s);
+		}
+	    }
+	}
+    }
+}
diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c
index 076a872c..b6b783b2 100644
--- a/sysdep/unix/main.c
+++ b/sysdep/unix/main.c
@@ -7,11 +7,72 @@
  */
 
 #include <stdio.h>
+#include <sys/signal.h>
 
 #include "nest/bird.h"
 #include "lib/lists.h"
 #include "lib/resource.h"
+#include "lib/socket.h"
 #include "nest/route.h"
+#include "nest/protocol.h"
+
+#include "unix.h"
+
+/*
+ *	Debugging
+ */
+
+static void
+handle_sigusr(int sig)
+{
+  debug("SIGUSR1: Debugging dump...\n\n");
+
+  sk_dump_all();
+  tm_dump_all();
+  rta_dump_all();
+  rt_dump_all();
+
+  debug("\n");
+}
+
+static void
+signal_init(void)
+{
+  static struct sigaction sa;
+
+  sa.sa_handler = handle_sigusr;
+  sa.sa_flags = SA_RESTART;
+  if (sigaction(SIGUSR1, &sa, NULL) < 0)
+    die("sigaction: %m");
+  signal(SIGPIPE, SIG_IGN);
+}
+
+/*
+ *	Hic Est main()
+ */
+
+void erro(sock *s, int e)
+{
+  debug("errrr e=%d\n", e);
+  rfree(s);
+}
+
+void bla(sock *s)
+{
+  puts("W");
+  strcpy(s->tbuf, "RAM!\r\n");
+  sk_send(s, 6);
+}
+
+int xxx(sock *s, int h)
+{
+  puts("R");
+  do {
+    strcpy(s->tbuf, "Hello, world!\r\n");
+  }
+  while (sk_send(s, 15) > 0);
+  return 1;
+}
 
 int
 main(void)
@@ -20,8 +81,32 @@ main(void)
 
   log_init_debug(NULL);
   resource_init();
+  io_init();
   rt_init();
-  proto_init();
+  protos_init();
+  signal_init();
 
-  return 0;
+  {
+    sock *s = sk_new(&root_pool);
+
+    if (!s)
+      die("no socket");
+    s->type = SK_UDP_MC;
+    s->sport = 7899;
+    s->saddr = _MI(0x3ea80015);
+    s->daddr = _MI(0xe0000001);
+    s->dport = 7890;
+    s->rx_hook = xxx;
+    s->tx_hook = bla;
+    s->err_hook = erro;
+    s->rbsize = 1024;
+    s->tbsize = 1024;
+    s->ttl = 1;
+    if (sk_open(s))
+      die("open failed");
+    bla(s);
+  }
+
+  io_loop();
+  die("I/O loop died");
 }
diff --git a/sysdep/unix/unix.h b/sysdep/unix/unix.h
new file mode 100644
index 00000000..2f98fcf6
--- /dev/null
+++ b/sysdep/unix/unix.h
@@ -0,0 +1,17 @@
+/*
+ *	BIRD -- Declarations Common to Unix Port
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_UNIX_H_
+#define _BIRD_UNIX_H_
+
+/* io.c */
+
+void io_init(void);
+void io_loop(void);
+
+#endif