Implemented scanning of network interfaces. Mostly very ugly code due to

terrible kernel interface (SIOGIFCONF and friends).

3 files changed, 199 insertions, 2 deletions

diff --git a/nest/Makefile b/nest/Makefile
index 0a9d5fe..aaa0c2a 100644
--- a/nest/Makefile
+++ b/nest/Makefile
@@ -1,4 +1,4 @@
 THISDIR=nest
-OBJS=rt-table.o rt-fib.o rt-attr.o proto.o
+OBJS=rt-table.o rt-fib.o rt-attr.o proto.o iface.o
 
 include ../Rules
diff --git a/nest/iface.c b/nest/iface.c
new file mode 100644
index 0000000..79a7b7d
--- /dev/null
+++ b/nest/iface.c
@@ -0,0 +1,177 @@
+/*
+ *	BIRD -- Management of Interfaces
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include "nest/bird.h"
+#include "nest/iface.h"
+#include "lib/resource.h"
+
+list iface_list;
+
+static pool *if_pool;
+
+void
+if_dump(struct iface *i)
+{
+  struct ifa *a;
+
+  debug("IF%d: %s", i->index, i->name);
+  if (i->flags & IF_ADMIN_DOWN)
+    debug(" ADMIN-DOWN");
+  if (i->flags & IF_UP)
+    debug(" UP");
+  if (i->flags & IF_MULTIACCESS)
+    debug(" MA");
+  if (i->flags & IF_UNNUMBERED)
+    debug(" UNNUM");
+  if (i->flags & IF_BROADCAST)
+    debug(" BC");
+  if (i->flags & IF_MULTICAST)
+    debug(" MC");
+  if (i->flags & IF_TUNNEL)
+    debug(" TUNL");
+  if (i->flags & IF_LOOPBACK)
+    debug(" LOOP");
+  if (i->flags & IF_IGNORE)
+    debug(" IGN");
+  debug(" MTU=%d\n", i->mtu);
+  for(a=i->ifa; a; a=a->next)
+    debug("\t%08x, net %08x/%-2d bc %08x -> %08x\n", _I(a->ip), _I(a->prefix), a->pxlen, _I(a->brd), _I(a->opposite));
+}
+
+void
+if_dump_all(void)
+{
+  struct iface *i;
+
+  debug("Known network interfaces:\n\n");
+  WALK_LIST(i, iface_list)
+    if_dump(i);
+  debug("\n");
+}
+
+struct if_with_a {
+  struct iface i;
+  struct ifa a[0];
+};
+
+static struct iface *
+if_copy(struct iface *j)
+{
+  int len;
+  struct if_with_a *w;
+  struct iface *i;
+  struct ifa *a, **b, *c;
+
+  len = 0;
+  for(a=j->ifa; a; a=a->next)
+    len++;
+  w = mb_alloc(if_pool, sizeof(struct if_with_a) + len*sizeof(struct ifa));
+  i = &w->i;
+  c = w->a;
+  memcpy(i, j, sizeof(struct iface));
+  b = &i->ifa;
+  a = j->ifa;
+  while (a)
+    {
+      *b = c;
+      memcpy(c, a, sizeof(struct ifa));
+      b = &c->next;
+      a = a->next;
+      c++;
+    }
+  *b = NULL;
+  return i;
+}
+
+static inline void
+if_free(struct iface *i)
+{
+  mb_free(i);
+}
+
+static unsigned
+if_changed(struct iface *i, struct iface *j)
+{
+  unsigned f = 0;
+  struct ifa *x, *y;
+
+  x = i->ifa;
+  y = j->ifa;
+  while (x && y)
+    {
+      x = x->next;
+      y = y->next;
+    }
+  if (x || y)
+    f |= IF_CHANGE_ADDR;
+  if (i->mtu != j->mtu)
+    f |= IF_CHANGE_MTU;
+  if (i->flags != j->flags)
+    {
+      f |= IF_CHANGE_FLAGS;
+      if ((i->flags ^ j->flags) & IF_UP)
+	if (i->flags & IF_UP)
+	  f |= IF_CHANGE_DOWN;
+	else
+	  f |= IF_CHANGE_UP;
+    }
+  return f;
+}
+
+static void
+if_notify_change(unsigned c, struct iface *old, struct iface *new)
+{
+  debug("Interface change notification (%x) for %s\n", c, new->name);
+}
+
+void
+if_update(struct iface *new)
+{
+  struct iface *i;
+
+  WALK_LIST(i, iface_list)
+    if (!strcmp(new->name, i->name))
+      {
+	unsigned c = if_changed(i, new);
+	if (c)
+	  {
+	    struct iface *j = if_copy(new);
+	    if_notify_change(c, i, j);
+	    insert_node(&j->n, &i->n);
+	    rem_node(&i->n);
+	    if_free(i);
+	  }
+	return;
+      }
+  i = if_copy(new);
+  add_tail(&iface_list, &i->n);
+  if_notify_change(IF_CHANGE_UP | IF_CHANGE_FLAGS | IF_CHANGE_MTU | IF_CHANGE_ADDR, NULL, i);
+}
+
+void
+if_end_update(void)
+{
+  struct iface *i, j;
+
+  WALK_LIST(i, iface_list)
+    if (i->flags & IF_UPDATED)
+      i->flags &= ~IF_UPDATED;
+    else
+      {
+	memcpy(&j, i, sizeof(struct iface));
+	i->flags = (i->flags & ~IF_UP) | IF_ADMIN_DOWN;
+	if_notify_change(IF_CHANGE_DOWN | IF_CHANGE_FLAGS, &j, i);
+      }
+}
+
+void
+if_init(void)
+{
+  if_pool = rp_new(&root_pool, "Interfaces");
+  init_list(&iface_list);
+}
diff --git a/nest/iface.h b/nest/iface.h
index 454c050..4df9873 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -11,9 +11,11 @@
 
 #include "lib/lists.h"
 
+extern list iface_list;
+
 struct iface {
   node n;
-  char *name;
+  char name[16];
   unsigned flags;
   unsigned mtu;
   struct ifa *ifa;			/* First address is primary */
@@ -26,6 +28,10 @@ struct iface {
 #define IF_BROADCAST 8
 #define IF_MULTICAST 16
 #define IF_TUNNEL 32
+#define IF_ADMIN_DOWN 64
+#define IF_LOOPBACK 128
+#define IF_IGNORE 256
+#define IF_UPDATED 0x1000		/* Touched in last scan */
 
 /* Interface address */
 
@@ -39,4 +45,18 @@ struct ifa {
   struct neighbor *neigh;		/* List of neighbors on this interface */
 };
 
+/* Interface change events */
+
+#define IF_CHANGE_UP 1
+#define IF_CHANGE_DOWN 2
+#define IF_CHANGE_FLAGS 4
+#define IF_CHANGE_MTU 8
+#define IF_CHANGE_ADDR 16
+
+void if_init(void);
+void if_dump(struct iface *);
+void if_dump_all(void);
+void if_update(struct iface *);
+void if_end_update(void);
+
 #endif