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.

1 files changed, 17 insertions, 171 deletions

diff --git a/sysdep/linux/krt-scan.c b/sysdep/linux/krt-scan.c
index 1428a7a..3e5a240 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