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/*
* 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\n", 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\n", 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 DEBUGGING
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->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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