From 62aa008abd627c6862310daf65ffd337a920bdbb Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Fri, 15 May 1998 07:54:32 +0000
Subject: Parts of routing table code. Data structure declarations should be
 complete now.

---
 nest/rt-fib.c | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 nest/rt-fib.c

(limited to 'nest/rt-fib.c')

diff --git a/nest/rt-fib.c b/nest/rt-fib.c
new file mode 100644
index 0000000..d7350ae
--- /dev/null
+++ b/nest/rt-fib.c
@@ -0,0 +1,150 @@
+/*
+ *	BIRD -- Forwarding Information Base -- Data Structures
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define LOCAL_DEBUG
+
+#include <string.h>
+
+#include "nest/bird.h"
+#include "nest/route.h"
+
+#define HASH_DEF_SIZE 1024
+#define HASH_HI_MARK *16
+#define HASH_LO_MARK *0
+#define HASH_LO_MIN 128
+#define HASH_HI_RESIZE *16
+#define HASH_LO_RESIZE *0
+
+static void
+fib_ht_alloc(struct fib *f)
+{
+  f->hash_mask = f->hash_size - 1;
+  f->entries_max = f->hash_size HASH_HI_MARK;
+  f->entries_min = f->hash_size HASH_LO_MARK;
+  if (f->entries_min < HASH_LO_MIN)
+    f->entries_min = 0;
+  DBG("Allocating FIB: %d entries, %d low, %d high", f->hash_size, f->entries_min, f->entries_max);
+  f->hash_table = mb_alloc(f->fib_pool, f->hash_size * sizeof(struct fib_node *));
+  bzero(f->hash_table, f->hash_size * sizeof(struct fib_node *));
+}
+
+static inline void
+fib_ht_free(struct fib_node **h)
+{
+  mb_free(h);
+}
+
+static inline unsigned
+fib_hash(struct fib *f, ip_addr *a)
+{
+  return ipa_hash(*a) & f->hash_mask;
+}
+
+void
+fib_init(struct fib *f, pool *p, unsigned node_size, unsigned hash_size, void (*init)(struct fib_node *))
+{
+  if (!hash_size)
+    hash_size = HASH_DEF_SIZE;
+  f->fib_pool = p;
+  f->fib_slab = sl_new(p, node_size);
+  f->hash_size = hash_size;
+  fib_ht_alloc(f);
+  f->entries = 0;
+  f->entries_min = 0;
+  f->init = init;
+}
+
+static void
+fib_rehash(struct fib *f, unsigned new)
+{
+  unsigned old;
+  struct fib_node **n, *e, *x, **t, **m, **h;
+
+  old = f->hash_size;
+  m = h = f->hash_table;
+  DBG("Re-hashing FIB from %d to %d", old, new);
+  f->hash_size = new;
+  fib_ht_alloc(f);
+  n = f->hash_table;
+  while (old--)
+    {
+      x = *h++;
+      while (e = x)
+	{
+	  x = e->next;
+	  t = n + fib_hash(f, &e->prefix);
+	  e->next = *t;
+	  *t = e;
+	}
+    }
+  fib_ht_free(m);
+}
+
+void *
+fib_find(struct fib *f, ip_addr *a, int len)
+{
+  struct fib_node *e = f->hash_table[fib_hash(f, a)];
+
+  while (e && (e->pxlen != len || !ipa_equal(*a, e->prefix)))
+    e = e->next;
+  return e;
+}
+
+void *
+fib_get(struct fib *f, ip_addr *a, int len)
+{
+  struct fib_node **ee = f->hash_table + fib_hash(f, a);
+  struct fib_node *e = *ee;
+
+  while (e && (e->pxlen != len || !ipa_equal(*a, e->prefix)))
+    e = e->next;
+  if (e)
+    return e;
+#ifdef DEBUG
+  if (len < 0 || len > BITS_PER_IP_ADDRESS || !ip_is_prefix(*a,len))
+    die("fib_get() called for invalid address");
+#endif
+  e = sl_alloc(f->fib_slab);
+  e->prefix = *a;
+  e->pxlen = len;
+  e->flags = 0;
+  e->next = *ee;
+  *ee = e;
+  f->init(e);
+  if (f->entries++ > f->entries_max)
+    fib_rehash(f, f->hash_size HASH_HI_RESIZE);
+  return e;
+}
+
+void
+fib_delete(struct fib *f, void *E)
+{
+  struct fib_node *e = E;
+  struct fib_node **ee = f->hash_table + fib_hash(f, &e->prefix);
+
+  while (*ee)
+    {
+      if (*ee == e)
+	{
+	  *ee = e->next;
+	  sl_free(f->fib_slab, e);
+	  if (f->entries-- < f->entries_min)
+	    fib_rehash(f, f->hash_size HASH_LO_RESIZE);
+	  return;
+	}
+      ee = &((*ee)->next);
+    }
+  die("fib_delete() called for invalid node");
+}
+
+void
+fib_free(struct fib *f)
+{
+  fib_ht_free(f->hash_table);
+  rfree(f->fib_slab);
+}
-- 
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