Rewrote the kernel syncer. The old layering was horrible.

The new kernel syncer is cleanly split between generic UNIX module
and OS dependent submodules:

  -  krt.c (the generic part)
  -  krt-iface (low-level functions for interface handling)
  -  krt-scan (low-level functions for routing table scanning)
  -  krt-set (low-level functions for setting of kernel routes)

krt-set and krt-iface are common for all BSD-like Unices, krt-scan is heavily
system dependent (most Unices require /dev/kmem parsing, Linux uses /proc),
Netlink substitues all three modules.

We expect each UNIX port supports kernel routing table scanning, kernel
interface table scanning, kernel route manipulation and possibly also
asynchronous event notifications (new route, interface state change;
not implemented yet) and build the KRT protocol on the top of these
primitive operations.

27 files changed, 546 insertions, 572 deletions

diff --git a/TODO b/TODO
index 8045604d..1544345f 100644
--- a/TODO
+++ b/TODO
@@ -14,6 +14,7 @@ Core
 - static: check validity of route destination?
 
 - device: configuration of interface patterns
+- device: what to do if we need to shut down this protocol?
 
 - adding of route: check whether all bits not covered by masklen are zero
 
diff --git a/doc/bird.conf.example b/doc/bird.conf.example
index 15fd8449..9f5907d4 100644
--- a/doc/bird.conf.example
+++ b/doc/bird.conf.example
@@ -24,6 +24,7 @@ protocol kernel {
 	persist			# Don't remove routes on bird shutdown
 	scan time 10		# Scan kernel tables every 10 seconds
 	route scan time 20	# But routes only every 20 seconds
+#	async off		# Netlink: Disable asynchronous events
 }
 
 protocol static {
diff --git a/sysdep/cf/linux-20.h b/sysdep/cf/linux-20.h
index 807ddcd6..e514218f 100644
--- a/sysdep/cf/linux-20.h
+++ b/sysdep/cf/linux-20.h
@@ -12,6 +12,10 @@
 #undef CONFIG_AUTO_ROUTES
 #define CONFIG_ALL_MULTICAST
 
+#define CONFIG_UNIX_IFACE
+#define CONFIG_UNIX_SET
+#define CONFIG_LINUX_SCAN
+
 /*
 Link: sysdep/linux
 Link: sysdep/unix
diff --git a/sysdep/linux/Modules b/sysdep/linux/Modules
index 03d032d9..4a99916a 100644
--- a/sysdep/linux/Modules
+++ b/sysdep/linux/Modules
@@ -1,5 +1,4 @@
-#ifndef CONFIG_NETLINK
+#ifdef CONFIG_LINUX_SCAN
 krt-scan.c
 krt-scan.h
-krt-scan.Y
 #endif
diff --git a/sysdep/linux/krt-scan.Y b/sysdep/linux/krt-scan.Y
deleted file mode 100644
index 58339895..00000000
--- a/sysdep/linux/krt-scan.Y
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- *	BIRD -- Linux Kernel Syncer Configuration
- *
- *	(c) 1998 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-CF_HDR
-
-#include "lib/krt-scan.h"
-
-CF_DECLS
-
-CF_KEYWORDS(LEARN, ROUTE, SCAN, TIME)
-
-CF_GRAMMAR
-
-CF_ADDTO(kern_proto, kern_proto krt_scan_item ';')
-
-krt_scan_item:
-   LEARN bool {
-      ((struct krt_config *) this_proto)->scanopt.learn = $2;
-   }
- | ROUTE SCAN TIME expr {
-      /* Scan time of 0 means scan on startup only */
-      ((struct krt_config *) this_proto)->scanopt.scan_time = $4;
-   }
- ;
-
-CF_CODE
-
-CF_END
diff --git a/sysdep/linux/krt-scan.c b/sysdep/linux/krt-scan.c
index 1428a7ac..3e5a2401 100644
--- a/sysdep/linux/krt-scan.c
+++ b/sysdep/linux/krt-scan.c
@@ -23,60 +23,34 @@
 #include "lib/unix.h"
 #include "lib/krt.h"
 
-#define SCANOPT struct krt_scan_params *p = &(((struct krt_config *)(x->p.cf))->scanopt)
-#define SCANSTAT struct krt_scan_status *s = &x->scanstat
-
 static int krt_scan_fd = -1;
 
-/* FIXME: Filtering */
-
 struct iface *
-krt_temp_iface(struct krt_proto *x, char *name)
+krt_temp_iface(struct krt_proto *p, char *name)
 {
-  SCANOPT;
-  SCANSTAT;
   struct iface *i;
 
-  WALK_LIST(i, s->temp_ifs)
+  WALK_LIST(i, p->scan.temp_ifs)
     if (!strcmp(i->name, name))
       return i;
-  i = mb_alloc(x->p.pool, sizeof(struct iface));
+  i = mb_alloc(p->p.pool, sizeof(struct iface));
   bzero(i, sizeof(*i));
   strcpy(i->name, name);
-  add_tail(&s->temp_ifs, &i->n);
+  add_tail(&p->scan.temp_ifs, &i->n);
   return i;
 }
 
-static int
-krt_uptodate(rte *k, rte *e)
-{
-  rta *ka = k->attrs, *ea = e->attrs;
-
-  if (ka->dest != ea->dest)
-    return 0;
-  switch (ka->dest)
-    {
-    case RTD_ROUTER:
-      return ipa_equal(ka->gw, ea->gw);
-    case RTD_DEVICE:
-      return !strcmp(ka->iface->name, ea->iface->name);
-    default:
-      return 1;
-    }
-}
-
 static void
-krt_parse_entry(byte *ent, struct krt_proto *x)
+krt_parse_entry(byte *ent, struct krt_proto *p)
 {
-  SCANOPT;
   u32 dest0, gw0, mask0;
   ip_addr dest, gw, mask;
-  unsigned int flags, verdict;
+  unsigned int flags;
   int masklen;
   net *net;
   byte *iface = ent;
   rta a;
-  rte *e, *old;
+  rte *e;
 
   if (sscanf(ent, "%*s\t%x\t%x\t%x\t%*d\t%*d\t%*d\t%x\t", &dest0, &gw0, &flags, &mask0) != 4)
     {
@@ -114,14 +88,8 @@ krt_parse_entry(byte *ent, struct krt_proto *x)
     }
 
   net = net_get(&master_table, 0, dest, masklen);
-  if (net->n.flags)
-    {
-      /* Route to this destination was already seen. Strange, but it happens... */
-      DBG("Already seen.\n");
-      return;
-    }
 
-  a.proto = &x->p;
+  a.proto = &p->p;
   a.source = RTS_INHERIT;
   a.scope = SCOPE_UNIVERSE;
   a.cast = RTC_UNICAST;
@@ -132,7 +100,7 @@ krt_parse_entry(byte *ent, struct krt_proto *x)
 
   if (flags & RTF_GATEWAY)
     {
-      neighbor *ng = neigh_find(&x->p, &gw, 0);
+      neighbor *ng = neigh_find(&p->p, &gw, 0);
       if (ng)
 	a.iface = ng->iface;
       else
@@ -150,7 +118,7 @@ krt_parse_entry(byte *ent, struct krt_proto *x)
     {
       a.dest = RTD_DEVICE;
       a.gw = IPA_NONE;
-      a.iface = krt_temp_iface(x, iface);
+      a.iface = krt_temp_iface(p, iface);
     }
   else
     {
@@ -160,43 +128,15 @@ krt_parse_entry(byte *ent, struct krt_proto *x)
 
   e = rte_get_temp(&a);
   e->net = net;
-  old = net->routes;
-  if (old && !krt_capable(old))
-    old = NULL;
-  if (old)
-    {
-      if (krt_uptodate(e, net->routes))
-	verdict = KRF_SEEN;
-      else
-	verdict = KRF_UPDATE;
-    }
-  else if (p->learn && !net->routes)
-    verdict = KRF_LEARN;
-  else
-    verdict = KRF_DELETE;
-
-  DBG("krt_parse_entry: verdict=%s\n", ((char *[]) { "CREATE", "SEEN", "UPDATE", "DELETE", "LEARN" }) [verdict]);
-
-  net->n.flags = verdict;
-  if (verdict != KRF_SEEN)
-    {
-      /* Get a cached copy of attributes and link the route */
-      a.source = RTS_DUMMY;
-      e->attrs = rta_lookup(&a);
-      e->next = net->routes;
-      net->routes = e;
-    }
-  else
-    rte_free(e);
+  krt_got_route(p, e);
 }
 
-static int
-krt_scan_proc(struct krt_proto *p)
+void
+krt_scan_fire(struct krt_proto *p)
 {
   byte buf[32768];
   int l, seen_hdr;
 
-  DBG("Scanning kernel routing table...\n");
   if (krt_scan_fd < 0)
     {
       krt_scan_fd = open("/proc/net/route", O_RDONLY);
@@ -206,7 +146,7 @@ krt_scan_proc(struct krt_proto *p)
   else if (lseek(krt_scan_fd, 0, SEEK_SET) < 0)
     {
       log(L_ERR "krt seek: %m");
-      return 0;
+      return;
     }
   seen_hdr = 0;
   while ((l = read(krt_scan_fd, buf, sizeof(buf))) > 0)
@@ -215,7 +155,7 @@ krt_scan_proc(struct krt_proto *p)
       if (l & 127)
 	{
 	  log(L_ERR "krt read: misaligned entry: l=%d", l);
-	  return 0;
+	  return;
 	}
       while (l >= 128)
 	{
@@ -228,114 +168,20 @@ krt_scan_proc(struct krt_proto *p)
   if (l < 0)
     {
       log(L_ERR "krt read: %m");
-      return 0;
+      return;
     }
   DBG("KRT scan done, seen %d lines\n", seen_hdr);
-  return 1;
-}
-
-static void
-krt_prune(struct krt_proto *p)
-{
-  struct rtable *t = &master_table;
-  struct fib_node *f;
-
-  DBG("Pruning routes...\n");
-  while (t && t->tos)
-    t = t->sibling;
-  if (!t)
-    return;
-  FIB_WALK(&t->fib, f)
-    {
-      net *n = (net *) f;
-      int verdict = f->flags;
-      rte *new, *old;
-
-      if (verdict != KRF_CREATE && verdict != KRF_SEEN)
-	{
-	  old = n->routes;
-	  n->routes = old->next;
-	}
-      else
-	old = NULL;
-      new = n->routes;
-
-      switch (verdict)
-	{
-	case KRF_CREATE:
-	  if (new)
-	    {
-	      if (new->attrs->source == RTS_INHERIT)
-		{
-		  DBG("krt_prune: removing inherited %I/%d\n", n->n.prefix, n->n.pxlen);
-		  rte_update(n, &p->p, NULL);
-		}
-	      else
-		{
-		  DBG("krt_prune: reinstalling %I/%d\n", n->n.prefix, n->n.pxlen);
-		  krt_add_route(new);
-		}
-	    }
-	  break;
-	case KRF_SEEN:
-	  /* Nothing happens */
-	  break;
-	case KRF_UPDATE:
-	  DBG("krt_prune: updating %I/%d\n", n->n.prefix, n->n.pxlen);
-	  krt_remove_route(old);
-	  krt_add_route(new);
-	  break;
-	case KRF_DELETE:
-	  DBG("krt_prune: deleting %I/%d\n", n->n.prefix, n->n.pxlen);
-	  krt_remove_route(old);
-	  break;
-	case KRF_LEARN:
-	  DBG("krt_prune: learning %I/%d\n", n->n.prefix, n->n.pxlen);
-	  rte_update(n, &p->p, new);
-	  break;
-	default:
-	  bug("krt_prune: invalid route status");
-	}
-
-      if (old)
-	rte_free(old);
-      f->flags = 0;
-    }
-  FIB_WALK_END;
-}
-
-void
-krt_scan_ifaces_done(struct krt_proto *x)
-{
-  SCANOPT;
-  SCANSTAT;
-
-  s->accum_time += ((struct krt_config *) x->p.cf)->ifopt.scan_time;
-  if (p->scan_time && s->accum_time >= p->scan_time)
-    {
-      s->accum_time %= p->scan_time;
-      if (krt_scan_proc(x))
-	krt_prune(x);
-    }
 }
 
 void
 krt_scan_preconfig(struct krt_config *c)
 {
-  c->scanopt.scan_time = 60;
-  c->scanopt.learn = 0;
 }
 
 void
 krt_scan_start(struct krt_proto *x)
 {
-  SCANOPT;
-  SCANSTAT;
-
-  /* Force krt scan after first interface scan */
-  s->accum_time = p->scan_time - ((struct krt_config *) x->p.cf)->ifopt.scan_time;
-
-  init_list(&s->temp_ifs);
+  init_list(&x->scan.temp_ifs);
 }
 
 void
diff --git a/sysdep/linux/krt-scan.h b/sysdep/linux/krt-scan.h
index ef1f7290..c5bf5884 100644
--- a/sysdep/linux/krt-scan.h
+++ b/sysdep/linux/krt-scan.h
@@ -1,5 +1,5 @@
 /*
- *	BIRD -- Linux Kernel Route Syncer -- Scanning Parameters
+ *	BIRD -- Linux Kernel Route Syncer -- Scanning
  *
  *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
  *
@@ -10,13 +10,10 @@
 #define _BIRD_KRT_SCAN_H_
 
 struct krt_scan_params {
-  int learn;				/* Should we learn routes from the kernel? */
-  int scan_time;			/* How often should we scan krt, 0=only on startup */
 };
 
 struct krt_scan_status {
   list temp_ifs;			/* Temporary interfaces */
-  int accum_time;			/* Accumulated scanning time */
 };
 
 #endif
diff --git a/sysdep/linux/netlink/Modules b/sysdep/linux/netlink/Modules
index 80338101..c26f7f72 100644
--- a/sysdep/linux/netlink/Modules
+++ b/sysdep/linux/netlink/Modules
@@ -1,3 +1,5 @@
-krt.c
-krt.h
-krt.Y
+krt-iface.h
+krt-set.h
+krt-scan.h
+netlink.c
+netlink.Y
diff --git a/sysdep/linux/netlink/krt-iface.h b/sysdep/linux/netlink/krt-iface.h
new file mode 100644
index 00000000..5dfb934f
--- /dev/null
+++ b/sysdep/linux/netlink/krt-iface.h
@@ -0,0 +1,26 @@
+/*
+ *	BIRD -- Unix Kernel Netlink Interface Syncer -- Dummy Include File
+ *
+ *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_KRT_IFACE_H_
+#define _BIRD_KRT_IFACE_H_
+
+/*
+ *  We don't have split iface/scan/set parts. See krt-scan.h.
+ */
+
+struct krt_if_params {
+};
+
+struct krt_if_status {
+};
+
+static inline void krt_if_preconfig(struct krt_config *c) { };
+static inline void krt_if_start(struct krt_proto *p) { };
+static inline void krt_if_shutdown(struct krt_proto *p) { };
+
+#endif
diff --git a/sysdep/linux/netlink/krt-scan.h b/sysdep/linux/netlink/krt-scan.h
new file mode 100644
index 00000000..cd118de4
--- /dev/null
+++ b/sysdep/linux/netlink/krt-scan.h
@@ -0,0 +1,26 @@
+/*
+ *	BIRD -- Linux Kernel Netlink Route Syncer -- Scanning
+ *
+ *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_KRT_SCAN_H_
+#define _BIRD_KRT_SCAN_H_
+
+/*
+ *  We don't have split iface/scan/set for Netlink. All options
+ *  and run-time parameters are declared here instead of splitting
+ *  to krt-set.h, krt-iface.h and this file.
+ */
+
+struct krt_scan_params {
+  int async;				/* Allow asynchronous events */
+};
+
+struct krt_scan_status {
+  list temp_ifs;			/* Temporary interfaces */
+};
+
+#endif
diff --git a/sysdep/linux/netlink/krt-set.h b/sysdep/linux/netlink/krt-set.h
new file mode 100644
index 00000000..32fdad0a
--- /dev/null
+++ b/sysdep/linux/netlink/krt-set.h
@@ -0,0 +1,26 @@
+/*
+ *	BIRD -- Unix Kernel Netlink Route Syncer -- Dummy Include File
+ *
+ *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_KRT_SET_H_
+#define _BIRD_KRT_SET_H_
+
+/*
+ *  We don't have split iface/scan/set parts. See krt-scan.h.
+ */
+
+struct krt_set_params {
+};
+
+struct krt_set_status {
+};
+
+static inline void krt_set_preconfig(struct krt_config *c) { };
+static inline void krt_set_start(struct krt_proto *p) { };
+static inline void krt_set_shutdown(struct krt_proto *p) { };
+
+#endif
diff --git a/sysdep/linux/netlink/krt.Y b/sysdep/linux/netlink/krt.Y
deleted file mode 100644
index c5726408..00000000
--- a/sysdep/linux/netlink/krt.Y
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- *	BIRD -- Netlink Interface Configuration
- *
- *	(c) 1999 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-CF_HDR
-
-#include "lib/krt.h"
-
-#define KRT_PROTO ((struct krt_config *) this_proto)
-
-CF_DECLS
-
-CF_KEYWORDS(KERNEL, PERSIST, ROUTE, SCAN, TIME, LEARN)
-
-CF_GRAMMAR
-
-/* Kernel protocol */
-
-CF_ADDTO(proto, kern_proto '}')
-
-kern_proto_start: proto_start KERNEL {
-     if (!(this_proto = cf_krt)) cf_error("Kernel protocol already defined");
-     cf_krt = NULL;
-   }
- ;
-
-kern_proto:
-   kern_proto_start '{'
- | kern_proto proto_item ';'
- | kern_proto kern_item ';'
- ;
-
-kern_item:
-   PERSIST bool { KRT_PROTO->persist = $2; }
- | SCAN TIME expr { KRT_PROTO->scan_time = $3; }
- | LEARN bool { KRT_PROTO->learn = $2; }
- | ROUTE SCAN TIME expr { KRT_PROTO->route_scan_time = $4; }
- ;
-
-CF_CODE
-
-CF_END
diff --git a/sysdep/linux/netlink/krt.h b/sysdep/linux/netlink/krt.h
deleted file mode 100644
index 8dd55cc5..00000000
--- a/sysdep/linux/netlink/krt.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- *	BIRD -- Linux Netlink Interface
- *
- *	(c) 1999 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-#ifndef _BIRD_NETLINK_KRT_H_
-#define _BIRD_NETLINK_KRT_H_
-
-extern struct protocol proto_unix_kernel;
-
-struct krt_config {
-  struct proto_config c;
-  int persist;			/* Keep routes when we exit */
-  int scan_time;		/* How often we re-scan interfaces */
-  int route_scan_time;		/* How often we re-scan routes */
-  int learn;			/* Learn routes from other sources */
-};
-
-extern struct proto_config *cf_krt;
-
-struct krt_proto {
-  struct proto p;
-};
-
-void scan_if_init(void);
-
-#endif
diff --git a/sysdep/linux/netlink/netlink.Y b/sysdep/linux/netlink/netlink.Y
new file mode 100644
index 00000000..b5c45f29
--- /dev/null
+++ b/sysdep/linux/netlink/netlink.Y
@@ -0,0 +1,25 @@
+/*
+ *	BIRD -- Linux Netlink Configuration
+ *
+ *	(c) 1999 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+CF_HDR
+
+CF_DECLS
+
+CF_KEYWORDS(ASYNC)
+
+CF_GRAMMAR
+
+CF_ADDTO(kern_proto, kern_proto nl_item ';')
+
+nl_item:
+   ASYNC bool { THIS_KRT->scan.async = $2; }
+ ;
+
+CF_CODE
+
+CF_END
diff --git a/sysdep/linux/netlink/krt.c b/sysdep/linux/netlink/netlink.c
index c399e201..6e6fafd3 100644
--- a/sysdep/linux/netlink/krt.c
+++ b/sysdep/linux/netlink/netlink.c
@@ -15,8 +15,6 @@
 
 #define LOCAL_DEBUG
 
-#undef ASYNC_NETLINK			/* Define if async notifications should be used (debug) */
-
 #include "nest/bird.h"
 #include "nest/route.h"
 #include "nest/protocol.h"
@@ -46,13 +44,11 @@
 #define MSG_TRUNC 0x20
 #endif
 
-struct proto_config *cf_krt;
-
 /*
  *	Synchronous Netlink interface
  */
 
-static int nl_sync_fd;			/* Unix socket for synchronous netlink actions */
+static int nl_sync_fd = -1;		/* Unix socket for synchronous netlink actions */
 static u32 nl_sync_seq;			/* Sequence number of last request sent */
 
 static byte *nl_rx_buffer;		/* Receive buffer */
@@ -62,6 +58,19 @@ static struct nlmsghdr *nl_last_hdr;	/* Recently received packet */
 static unsigned int nl_last_size;
 
 static void
+nl_open(void)
+{
+  if (nl_sync_fd < 0)
+    {
+      nl_sync_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+      if (nl_sync_fd < 0)
+	die("Unable to open rtnetlink socket: %m");
+      nl_sync_seq = now;
+      nl_rx_buffer = xmalloc(nl_rx_size);
+    }
+}
+
+static void
 nl_send(void *rq, int size)
 {
   struct nlmsghdr *nh = rq;
@@ -327,8 +336,8 @@ nl_parse_addr(struct nlmsghdr *h)
   if_update(&f);
 }
 
-static void
-nl_scan_ifaces(void)
+void
+krt_if_scan(struct krt_proto *p)
 {
   struct nlmsghdr *h;
 
@@ -352,46 +361,48 @@ nl_scan_ifaces(void)
 }
 
 /*
- *	Asynchronous Netlink interface
+ *	Routes
  */
 
-static sock *nl_async_sk;		/* BIRD socket for asynchronous notifications */
+int
+krt_capable(rte *e)
+{
+  return 1;	/* FIXME */
+}
 
-static int
-nl_async_hook(sock *sk, int size)
+void
+krt_set_notify(struct proto *p, net *n, rte *new, rte *old)
+{
+  /* FIXME */
+}
+
+void
+krt_scan_fire(struct krt_proto *p)
 {
-  DBG("nl_async_hook\n");
-  return 0;
 }
 
 /*
- *	Protocol core
+ *	Asynchronous Netlink interface
  */
 
-static void
-krt_preconfig(struct protocol *x, struct config *c)
-{
-  struct krt_config *z = proto_config_new(&proto_unix_kernel, sizeof(struct krt_config));
-
-  cf_krt = &z->c;
-  z->c.preference = DEF_PREF_UKR;
-}
+static sock *nl_async_sk;		/* BIRD socket for asynchronous notifications */
 
-static struct proto *
-krt_init(struct proto_config *c)
+static int
+nl_async_hook(sock *sk, int size)
 {
-  struct krt_proto *p = proto_new(c, sizeof(struct krt_proto));
-
-  return &p->p;
+  DBG("nl_async_hook\n");
+  return 0;
 }
 
 static void
-nl_open_async(struct proto *p)
+nl_open_async(struct krt_proto *p)
 {
   sock *sk;
   struct sockaddr_nl sa;
 
-  sk = nl_async_sk = sk_new(p->pool);
+  DBG("KRT: Opening async netlink socket\n");
+
+  sk = nl_async_sk = sk_new(p->p.pool);
   sk->type = SK_MAGIC;
   sk->rx_hook = nl_async_hook;
   sk->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
@@ -405,43 +416,25 @@ nl_open_async(struct proto *p)
     die("Unable to bind secondary rtnetlink socket: %m");
 }
 
-static int
-krt_start(struct proto *p)
-{
-#ifdef ASYNC_NETLINK
-  nl_open_async(p);
-#endif
-
-  /* FIXME: Filter kernel routing table etc. */
+/*
+ *	Interface to the UNIX krt module
+ */
 
-  return PS_UP;
+void
+krt_scan_preconfig(struct krt_config *x)
+{
+  x->scan.async = 1;
 }
 
-static int
-krt_shutdown(struct proto *p)
+void
+krt_scan_start(struct krt_proto *p)
 {
-  /* FIXME: Remove all our routes from the kernel */
-
-  return PS_DOWN;
+  nl_open();
+  if (KRT_CF->scan.async)
+    nl_open_async(p);
 }
 
 void
-scan_if_init(void)
+krt_scan_shutdown(struct krt_proto *p)
 {
-  nl_sync_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
-  if (nl_sync_fd < 0)
-    die("Unable to open rtnetlink socket: %m");
-  nl_sync_seq = now;
-  nl_rx_buffer = xmalloc(nl_rx_size);
-  /* FIXME: Should we fetch our local address and compare it with addresses of all incoming messages? */
-
-  nl_scan_ifaces();
 }
-
-struct protocol proto_unix_kernel = {
-  name:		"Kernel",
-  preconfig:	krt_preconfig,
-  init:		krt_init,
-  start:	krt_start,
-  shutdown:	krt_shutdown
-};
diff --git a/sysdep/unix/Modules b/sysdep/unix/Modules
index e2ff0f85..bb0385d5 100644
--- a/sysdep/unix/Modules
+++ b/sysdep/unix/Modules
@@ -4,14 +4,16 @@ timer.h
 io.c
 unix.h
 
-#ifndef CONFIG_NETLINK
-sync-if.c
-sync-rt.c
-krt.Y
+krt.c
 krt.h
+krt.Y
+
+#ifdef CONFIG_UNIX_IFACE
+krt-iface.c
+krt-iface.h
+#endif
+
+#ifdef CONFIG_UNIX_SET
 krt-set.c
 krt-set.h
-krt-set.Y
-krt-iface.h
-krt-iface.Y
 #endif
diff --git a/sysdep/unix/krt-iface.Y b/sysdep/unix/krt-iface.Y
deleted file mode 100644
index c74eb02b..00000000
--- a/sysdep/unix/krt-iface.Y
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- *	BIRD -- UNIX Interface Syncer Configuration
- *
- *	(c) 1998 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-CF_HDR
-
-#include "lib/krt-scan.h"
-
-CF_DECLS
-
-CF_KEYWORDS(LEARN, ROUTE, SCAN, TIME)
-
-CF_GRAMMAR
-
-CF_ADDTO(kern_proto, kern_proto krt_if_item ';')
-
-krt_if_item:
-   SCAN TIME expr {
-      /* Scan time of 0 means scan on startup only */
-      ((struct krt_config *) this_proto)->ifopt.scan_time = $3;
-   }
- ;
-
-CF_CODE
-
-CF_END
diff --git a/sysdep/unix/sync-if.c b/sysdep/unix/krt-iface.c
index 3dfa4f01..3b665a44 100644
--- a/sysdep/unix/sync-if.c
+++ b/sysdep/unix/krt-iface.c
@@ -24,9 +24,7 @@
 
 #include "unix.h"
 
-int if_scan_sock;
-
-static timer *if_scan_timer;
+int if_scan_sock = -1;
 
 static void
 scan_ifs(struct ifreq *r, int cnt)
@@ -132,15 +130,13 @@ scan_ifs(struct ifreq *r, int cnt)
   if_end_update();
 }
 
-static void
-scan_if(timer *t)
+void
+krt_if_scan(struct krt_proto *p)
 {
   struct ifconf ic;
   static int last_ifbuf_size = 4*sizeof(struct ifreq);
   int res;
-  struct krt_proto *p = t->data;
 
-  DBG("It's interface scan time...\n");
   for(;;)
     {
       if (last_ifbuf_size)
@@ -173,40 +169,26 @@ scan_if(timer *t)
       DBG("Increased ifconf buffer size to %d\n", last_ifbuf_size);
 #endif
     }
-  krt_scan_ifaces_done(p);
-}
-
-void
-krt_if_start(struct krt_proto *p)
-{
-  struct krt_config *c = (struct krt_config *) p->p.cf;
-
-  if_scan_timer = tm_new(p->p.pool);
-  if_scan_timer->hook = scan_if;
-  if_scan_timer->data = p;
-  if_scan_timer->recurrent = c->ifopt.scan_time;
-  scan_if(if_scan_timer);
-  tm_start(if_scan_timer, c->ifopt.scan_time);
 }
 
 void
 krt_if_preconfig(struct krt_config *c)
 {
-  c->ifopt.scan_time = 60;
 }
 
 void
-krt_if_shutdown(struct krt_proto *p)
+krt_if_start(struct krt_proto *p)
 {
-  tm_stop(if_scan_timer);
-  /* FIXME: What should we do with interfaces? */
+  if (if_scan_sock < 0)
+    {
+      if_scan_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+      DBG("Using socket %d for interface and route scanning\n", if_scan_sock);
+      if (if_scan_sock < 0)
+	die("Cannot create scanning socket: %m");
+    }
 }
 
 void
-scan_if_init(void)
+krt_if_shutdown(struct krt_proto *p)
 {
-  if_scan_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
-  DBG("Using socket %d for interface and route scanning\n", if_scan_sock);
-  if (if_scan_sock < 0)
-    die("Cannot create scanning socket: %m");
 }
diff --git a/sysdep/unix/krt-iface.h b/sysdep/unix/krt-iface.h
index 87c88515..b27e86dc 100644
--- a/sysdep/unix/krt-iface.h
+++ b/sysdep/unix/krt-iface.h
@@ -1,5 +1,5 @@
 /*
- *	BIRD -- Unix Kernel Interface Syncer -- Setting Parameters
+ *	BIRD -- Unix Kernel Interface Syncer
  *
  *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
  *
@@ -10,10 +10,11 @@
 #define _BIRD_KRT_IFACE_H_
 
 struct krt_if_params {
-  int scan_time;
 };
 
 struct krt_if_status {
 };
 
+extern int if_scan_sock;
+
 #endif
diff --git a/sysdep/unix/krt-set.Y b/sysdep/unix/krt-set.Y
deleted file mode 100644
index 551ee16d..00000000
--- a/sysdep/unix/krt-set.Y
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- *	BIRD -- UNIX Kernel Syncer Configuration
- *
- *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-CF_HDR
-
-#include "lib/krt-scan.h"
-
-CF_DECLS
-
-CF_KEYWORDS(PERSIST)
-
-CF_GRAMMAR
-
-CF_ADDTO(kern_proto, kern_proto krt_set_item ';')
-
-krt_set_item:
-   PERSIST bool {
-      ((struct krt_config *) this_proto)->setopt.persist = $2;
-   }
- ;
-
-CF_CODE
-
-CF_END
diff --git a/sysdep/unix/krt-set.c b/sysdep/unix/krt-set.c
index e77015b3..dae01f46 100644
--- a/sysdep/unix/krt-set.c
+++ b/sysdep/unix/krt-set.c
@@ -84,7 +84,7 @@ krt_ioctl(int ioc, rte *e, char *name)
     log(L_ERR "%s(%I/%d): %m", name, net->n.prefix, net->n.pxlen);
 }
 
-void
+static void
 krt_remove_route(rte *old)
 {
   net *net = old->net;
@@ -98,7 +98,7 @@ krt_remove_route(rte *old)
   krt_ioctl(SIOCDELRT, old, "SIOCDELRT");
 }
 
-void
+static void
 krt_add_route(rte *new)
 {
   net *net = new->net;
@@ -126,7 +126,6 @@ krt_set_start(struct krt_proto *x)
 {
   if (if_scan_sock < 0)
     bug("krt set: missing socket");
-  x->p.rt_notify = krt_set_notify;
 }
 
 void
@@ -137,25 +136,4 @@ krt_set_preconfig(struct krt_config *c)
 void
 krt_set_shutdown(struct krt_proto *x)
 {
-  struct rtable *t = &master_table;
-
-  if (((struct krt_config *) x->p.cf)->setopt.persist)
-    return;
-  DBG("Flushing kernel routes...\n");
-  while (t && t->tos)
-    t = t->sibling;
-  if (!t)
-    return;
-  FIB_WALK(&t->fib, f)
-    {
-      net *n = (net *) f;
-      rte *e = n->routes;
-      if (e)
-	{
-	  rta *a = e->attrs;
-	  if (a->source != RTS_DEVICE && a->source != RTS_INHERIT)
-	    krt_remove_route(e);
-	}
-    }
-  FIB_WALK_END;
 } 
diff --git a/sysdep/unix/krt-set.h b/sysdep/unix/krt-set.h
index ec96e652..cfa5fb76 100644
--- a/sysdep/unix/krt-set.h
+++ b/sysdep/unix/krt-set.h
@@ -1,5 +1,5 @@
 /*
- *	BIRD -- Unix Kernel Route Syncer -- Setting Parameters
+ *	BIRD -- Unix Kernel Route Syncer -- Setting
  *
  *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
  *
@@ -10,15 +10,9 @@
 #define _BIRD_KRT_SET_H_
 
 struct krt_set_params {
-  int persist;
 };
 
 struct krt_set_status {
 };
 
-void krt_remove_route(rte *old);
-void krt_add_route(rte *new);
-int krt_capable(rte *e);
-void krt_set_notify(struct proto *x, net *net, rte *new, rte *old);
-
 #endif
diff --git a/sysdep/unix/krt.Y b/sysdep/unix/krt.Y
index 7711f3ba..661e5052 100644
--- a/sysdep/unix/krt.Y
+++ b/sysdep/unix/krt.Y
@@ -10,9 +10,11 @@ CF_HDR
 
 #include "lib/krt.h"
 
+#define THIS_KRT ((struct krt_config *) this_proto)
+
 CF_DECLS
 
-CF_KEYWORDS(KERNEL)
+CF_KEYWORDS(KERNEL, PERSIST, SCAN, TIME, ROUTE, LEARN)
 
 CF_GRAMMAR
 
@@ -28,6 +30,17 @@ kern_proto_start: proto_start KERNEL {
 
 CF_ADDTO(kern_proto, kern_proto_start '{')
 CF_ADDTO(kern_proto, kern_proto proto_item ';')
+CF_ADDTO(kern_proto, kern_proto kern_item ';')
+
+kern_item:
+   PERSIST bool { THIS_KRT->persist = $2; }
+ | SCAN TIME expr {
+      /* Scan time of 0 means scan on startup only */
+      THIS_KRT->scan_time = $3;
+   }
+ | ROUTE SCAN TIME expr { THIS_KRT->route_scan_time = $4; }
+ | LEARN bool { THIS_KRT->learn = $2; }
+ ;
 
 CF_CODE
 
diff --git a/sysdep/unix/krt.c b/sysdep/unix/krt.c
new file mode 100644
index 00000000..d44a57d8
--- /dev/null
+++ b/sysdep/unix/krt.c
@@ -0,0 +1,291 @@
+/*
+ *	BIRD -- UNIX Kernel Synchronization
+ *
+ *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define LOCAL_DEBUG
+
+#include "nest/bird.h"
+#include "nest/iface.h"
+#include "nest/route.h"
+#include "nest/protocol.h"
+#include "lib/timer.h"
+
+#include "unix.h"
+#include "krt.h"
+
+struct proto_config *cf_krt;
+
+/*
+ *	Routes
+ */
+
+static void
+krt_flush_routes(struct krt_proto *p)
+{
+  struct rtable *t = &master_table;
+
+  DBG("Flushing kernel routes...\n");
+  while (t && t->tos)
+    t = t->sibling;
+  if (!t)
+    return;
+  FIB_WALK(&t->fib, f)
+    {
+      net *n = (net *) f;
+      rte *e = n->routes;
+      if (e)
+	{
+	  rta *a = e->attrs;
+	  if (a->source != RTS_DEVICE && a->source != RTS_INHERIT)
+	    krt_set_notify(&p->p, e->net, e, NULL);
+	}
+    }
+  FIB_WALK_END;
+}
+
+/* FIXME: Inbound/outbound route filtering? */
+/* FIXME: Synchronization of multiple routing tables? */
+
+static int
+krt_uptodate(rte *k, rte *e)
+{
+  rta *ka = k->attrs, *ea = e->attrs;
+
+  if (ka->dest != ea->dest)
+    return 0;
+  switch (ka->dest)
+    {
+    case RTD_ROUTER:
+      return ipa_equal(ka->gw, ea->gw);
+    case RTD_DEVICE:
+      return !strcmp(ka->iface->name, ea->iface->name);
+    default:
+      return 1;
+    }
+}
+
+/*
+ *  This gets called back when the low-level scanning code discovers a route.
+ *  We expect that the route is a temporary rte and its attributes are uncached.
+ */
+
+void
+krt_got_route(struct krt_proto *p, rte *e)
+{
+  rte *old;
+  net *net = e->net;
+  int verdict;
+
+  if (net->n.flags)
+    {
+      /* Route to this destination was already seen. Strange, but it happens... */
+      DBG("Already seen.\n");
+      return;
+    }
+
+  old = net->routes;
+  if (old && !krt_capable(old))
+    old = NULL;
+  if (old)
+    {
+      if (krt_uptodate(e, net->routes))
+	verdict = KRF_SEEN;
+      else
+	verdict = KRF_UPDATE;
+    }
+  else if (KRT_CF->learn && !net->routes)
+    verdict = KRF_LEARN;
+  else
+    verdict = KRF_DELETE;
+
+  DBG("krt_parse_entry: verdict=%s\n", ((char *[]) { "CREATE", "SEEN", "UPDATE", "DELETE", "LEARN" }) [verdict]);
+
+  net->n.flags = verdict;
+  if (verdict != KRF_SEEN)
+    {
+      /* Get a cached copy of attributes and link the route */
+      rta *a = e->attrs;
+      a->source = RTS_DUMMY;
+      e->attrs = rta_lookup(a);
+      e->next = net->routes;
+      net->routes = e;
+    }
+  else
+    rte_free(e);
+}
+
+static void
+krt_prune(struct krt_proto *p)
+{
+  struct proto *pp = &p->p;
+  struct rtable *t = &master_table;
+  struct fib_node *f;
+
+  DBG("Pruning routes...\n");
+  while (t && t->tos)
+    t = t->sibling;
+  if (!t)
+    return;
+  FIB_WALK(&t->fib, f)
+    {
+      net *n = (net *) f;
+      int verdict = f->flags;
+      rte *new, *old;
+
+      if (verdict != KRF_CREATE && verdict != KRF_SEEN)
+	{
+	  old = n->routes;
+	  n->routes = old->next;
+	}
+      else
+	old = NULL;
+      new = n->routes;
+
+      switch (verdict)
+	{
+	case KRF_CREATE:
+	  if (new)
+	    {
+	      if (new->attrs->source == RTS_INHERIT)
+		{
+		  DBG("krt_prune: removing inherited %I/%d\n", n->n.prefix, n->n.pxlen);
+		  rte_update(n, pp, NULL);
+		}
+	      else
+		{
+		  DBG("krt_prune: reinstalling %I/%d\n", n->n.prefix, n->n.pxlen);
+		  krt_set_notify(pp, n, new, NULL);
+		}
+	    }
+	  break;
+	case KRF_SEEN:
+	  /* Nothing happens */
+	  break;
+	case KRF_UPDATE:
+	  DBG("krt_prune: updating %I/%d\n", n->n.prefix, n->n.pxlen);
+	  krt_set_notify(pp, n, new, old);
+	  break;
+	case KRF_DELETE:
+	  DBG("krt_prune: deleting %I/%d\n", n->n.prefix, n->n.pxlen);
+	  krt_set_notify(pp, n, NULL, old);
+	  break;
+	case KRF_LEARN:
+	  DBG("krt_prune: learning %I/%d\n", n->n.prefix, n->n.pxlen);
+	  rte_update(n, pp, new);
+	  break;
+	default:
+	  bug("krt_prune: invalid route status");
+	}
+
+      if (old)
+	rte_free(old);
+      f->flags = 0;
+    }
+  FIB_WALK_END;
+}
+
+/*
+ *	Periodic scanning
+ */
+
+static timer *krt_scan_timer;
+
+static void
+krt_scan(timer *t)
+{
+  struct krt_proto *p = t->data;
+
+  DBG("KRT: It's scan time...\n");
+  krt_if_scan(p);
+
+  p->accum_time += KRT_CF->scan_time;
+  if (KRT_CF->route_scan_time && p->accum_time >= KRT_CF->route_scan_time)
+    {
+      p->accum_time %= KRT_CF->route_scan_time;
+      DBG("Scanning kernel routing table...\n");
+      krt_scan_fire(p);
+      krt_prune(p);
+    }
+}
+
+/*
+ *	Protocol glue
+ */
+
+static int
+krt_start(struct proto *P)
+{
+  struct krt_proto *p = (struct krt_proto *) P;
+
+  p->accum_time = 0;
+
+  krt_if_start(p);
+  krt_scan_start(p);
+  krt_set_start(p);
+
+  /* Start periodic interface scanning */
+  krt_scan_timer = tm_new(P->pool);
+  krt_scan_timer->hook = krt_scan;
+  krt_scan_timer->data = p;
+  krt_scan_timer->recurrent = KRT_CF->scan_time;
+  krt_scan(krt_scan_timer);
+  tm_start(krt_scan_timer, KRT_CF->scan_time);
+
+  return PS_UP;
+}
+
+int
+krt_shutdown(struct proto *P)
+{
+  struct krt_proto *p = (struct krt_proto *) P;
+
+  if (!KRT_CF->persist)
+    krt_flush_routes(p);
+
+  krt_set_shutdown(p);
+  krt_scan_shutdown(p);
+
+  /* Stop periodic interface scans */
+  tm_stop(krt_scan_timer);
+  krt_if_shutdown(p);
+  /* FIXME: What should we do with interfaces? */
+
+  return PS_DOWN;
+}
+
+static void
+krt_preconfig(struct protocol *x, struct config *c)
+{
+  struct krt_config *z = proto_config_new(&proto_unix_kernel, sizeof(struct krt_config));
+
+  cf_krt = &z->c;
+  z->c.preference = DEF_PREF_UKR;
+  z->scan_time = z->route_scan_time = 60;
+  z->learn = z->persist = 0;
+
+  krt_scan_preconfig(z);
+  krt_set_preconfig(z);
+  krt_if_preconfig(z);
+}
+
+static struct proto *
+krt_init(struct proto_config *c)
+{
+  struct krt_proto *p = proto_new(c, sizeof(struct krt_proto));
+
+  p->p.rt_notify = krt_set_notify;
+  return &p->p;
+}
+
+struct protocol proto_unix_kernel = {
+  name:		"Kernel",
+  priority:	90,
+  preconfig:	krt_preconfig,
+  init:		krt_init,
+  start:	krt_start,
+  shutdown:	krt_shutdown,
+};
diff --git a/sysdep/unix/krt.h b/sysdep/unix/krt.h
index cebf3354..1c59799f 100644
--- a/sysdep/unix/krt.h
+++ b/sysdep/unix/krt.h
@@ -1,7 +1,7 @@
 /*
- *	BIRD -- Unix Kernel Route Syncer
+ *	BIRD -- UNIX Kernel Route Syncer
  *
- *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
  *
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
@@ -9,6 +9,9 @@
 #ifndef _BIRD_KRT_H_
 #define _BIRD_KRT_H_
 
+struct krt_config;
+struct krt_proto;
+
 #include "lib/krt-scan.h"
 #include "lib/krt-set.h"
 #include "lib/krt-iface.h"
@@ -21,32 +24,42 @@
 #define KRF_DELETE 3			/* Should be deleted */
 #define KRF_LEARN 4			/* We should learn this route */
 
-/* sync-rt.c */
+/* krt.c */
 
 extern struct protocol proto_unix_kernel;
 
 struct krt_config {
   struct proto_config c;
-  struct krt_set_params setopt;
-  struct krt_scan_params scanopt;
-  struct krt_if_params ifopt;
+  struct krt_set_params set;
+  struct krt_scan_params scan;
+  struct krt_if_params iface;
+  int persist;			/* Keep routes when we exit */
+  int scan_time;		/* How often we re-scan interfaces */
+  int route_scan_time;		/* How often we re-scan routes */
+  int learn;			/* Learn routes from other sources */
 };
 
 struct krt_proto {
   struct proto p;
-  struct krt_set_status setstat;
-  struct krt_scan_status scanstat;
-  struct krt_if_status ifstat;
+  struct krt_set_status set;
+  struct krt_scan_status scan;
+  struct krt_if_status iface;
+  int accum_time;	        /* Accumulated route scanning time */
 };
 
 extern struct proto_config *cf_krt;
 
+#define KRT_CF ((struct krt_config *)p->p.cf)
+
+void krt_got_route(struct krt_proto *p, struct rte *e);
+
 /* krt-scan.c */
 
 void krt_scan_preconfig(struct krt_config *);
 void krt_scan_start(struct krt_proto *);
 void krt_scan_shutdown(struct krt_proto *);
-void krt_scan_ifaces_done(struct krt_proto *);
+
+void krt_scan_fire(struct krt_proto *);
 
 /* krt-set.c */
 
@@ -54,15 +67,15 @@ void krt_set_preconfig(struct krt_config *);
 void krt_set_start(struct krt_proto *);
 void krt_set_shutdown(struct krt_proto *);
 
-/* sync-if.c */
-
-extern int if_scan_sock;
-extern int if_scan_period;
+int krt_capable(rte *e);
+void krt_set_notify(struct proto *x, net *net, rte *new, rte *old);
 
-void scan_if_init(void);
+/* krt-iface.c */
 
 void krt_if_preconfig(struct krt_config *);
 void krt_if_start(struct krt_proto *);
 void krt_if_shutdown(struct krt_proto *);
 
+void krt_if_scan(struct krt_proto *);
+
 #endif
diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c
index 71bb712a..e5e9934c 100644
--- a/sysdep/unix/main.c
+++ b/sysdep/unix/main.c
@@ -204,8 +204,6 @@ main(int argc, char **argv)
 
   signal_init();
 
-  scan_if_init();
-
   protos_start();
 
   ev_run_list(&global_event_list);
diff --git a/sysdep/unix/sync-rt.c b/sysdep/unix/sync-rt.c
deleted file mode 100644
index 99ef92a0..00000000
--- a/sysdep/unix/sync-rt.c
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- *	BIRD -- Unix Routing Table Scanning and Syncing
- *
- *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
- *
- *	Can be freely distributed and used under the terms of the GNU GPL.
- */
-
-#include <string.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <sys/ioctl.h>
-#include <errno.h>
-
-#define LOCAL_DEBUG
-
-#include "nest/bird.h"
-#include "nest/iface.h"
-#include "nest/route.h"
-#include "nest/protocol.h"
-#include "lib/timer.h"
-
-#include "unix.h"
-#include "krt.h"
-
-struct proto_config *cf_krt;
-
-static int
-krt_start(struct proto *p)
-{
-  struct krt_proto *k = (struct krt_proto *) p;
-
-  krt_scan_start(k);
-  krt_set_start(k);
-  krt_if_start(k);
-  return PS_UP;
-}
-
-int
-krt_shutdown(struct proto *p)
-{
-  struct krt_proto *k = (struct krt_proto *) p;
-
-  krt_scan_shutdown(k);
-  krt_if_shutdown(k);
-  krt_set_shutdown(k);
-  return PS_DOWN;
-}
-
-static void
-krt_preconfig(struct protocol *x, struct config *c)
-{
-  struct krt_config *z = proto_config_new(&proto_unix_kernel, sizeof(struct krt_config));
-
-  cf_krt = &z->c;
-  z->c.preference = DEF_PREF_UKR;
-  krt_scan_preconfig(z);
-  krt_set_preconfig(z);
-  krt_if_preconfig(z);
-}
-
-static struct proto *
-krt_init(struct proto_config *c)
-{
-  struct krt_proto *p = proto_new(c, sizeof(struct krt_proto));
-
-  return &p->p;
-}
-
-struct protocol proto_unix_kernel = {
-  name:		"Kernel",
-  preconfig:	krt_preconfig,
-  init:		krt_init,
-  start:	krt_start,
-  shutdown:	krt_shutdown,
-};