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.

8 files changed, 161 insertions, 139 deletions

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
-};