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/*
* BIRD -- OSPF Topological Database
*
* (c) 1999 Martin Mares <mj@ucw.cz>
* (c) 1999 Ondrej Filip <feela@network.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 "ospf.h"
#define HASH_DEF_ORDER 6 /* FIXME: Increase */
#define HASH_HI_MARK *4
#define HASH_HI_STEP 2
#define HASH_HI_MAX 16
#define HASH_LO_MARK /5
#define HASH_LO_STEP 2
#define HASH_LO_MIN 8
static void
ospf_top_ht_alloc(struct top_graph *f)
{
f->hash_size = 1 << f->hash_order;
f->hash_mask = f->hash_size - 1;
if (f->hash_order > HASH_HI_MAX - HASH_HI_STEP)
f->hash_entries_max = ~0;
else
f->hash_entries_max = f->hash_size HASH_HI_MARK;
if (f->hash_order < HASH_LO_MIN + HASH_LO_STEP)
f->hash_entries_min = 0;
else
f->hash_entries_min = f->hash_size HASH_LO_MARK;
DBG("Allocating OSPF hash of order %d: %d hash_entries, %d low, %d high\n",
f->hash_order, f->hash_size, f->hash_entries_min, f->hash_entries_max);
f->hash_table = mb_alloc(f->pool, f->hash_size * sizeof(struct top_hash_entry *));
bzero(f->hash_table, f->hash_size * sizeof(struct top_hash_entry *));
}
static inline void
ospf_top_ht_free(struct top_hash_entry **h)
{
mb_free(h);
}
static inline u32
ospf_top_hash_u32(u32 a)
{
/* Shamelessly stolen from IP address hashing in ipv4.h */
a ^= a >> 16;
a ^= a << 10;
return a;
}
static inline unsigned
ospf_top_hash(struct top_graph *f, u32 lsaid, u32 rtrid, u32 type)
{
return (ospf_top_hash_u32(lsaid) + ospf_top_hash_u32(rtrid) + type) & f->hash_mask;
}
struct top_graph *
ospf_top_new(struct proto_ospf *p)
{
struct top_graph *f;
f = mb_allocz(p->proto.pool, sizeof(struct top_graph));
f->pool = p->proto.pool;
f->hash_slab = sl_new(f->pool, sizeof(struct top_hash_entry));
f->hash_order = HASH_DEF_ORDER;
ospf_top_ht_alloc(f);
f->hash_entries = 0;
f->hash_entries_min = 0;
return f;
}
void
ospf_top_free(struct top_graph *f)
{
rfree(f->hash_slab);
ospf_top_ht_free(f->hash_table);
mb_free(f);
}
static void
ospf_top_rehash(struct top_graph *f, int step)
{
unsigned int oldn, oldh;
struct top_hash_entry **n, **oldt, **newt, *e, *x;
oldn = f->hash_size;
oldt = f->hash_table;
DBG("Re-hashing topology hash from order %d to %d\n", f->hash_order, f->hash_order+step);
f->hash_order += step;
ospf_top_ht_alloc(f);
newt = f->hash_table;
for(oldh=0; oldh < oldn; oldh++)
{
e = oldt[oldh];
while (e)
{
x = e->next;
n = newt + ospf_top_hash(f, e->lsa_id, e->rtr_id, e->lsa_type);
e->next = *n;
*n = e;
e = x;
}
}
ospf_top_ht_free(oldt);
}
struct top_hash_entry *
ospf_hash_find(struct top_graph *f, u32 lsa, u32 rtr, u32 type)
{
struct top_hash_entry *e = f->hash_table[ospf_top_hash(f, lsa, rtr, type)];
while (e && (e->lsa_id != lsa || e->rtr_id != rtr || e->lsa_type != type))
e = e->next;
return e;
}
struct top_hash_entry *
ospf_hash_get(struct top_graph *f, u32 lsa, u32 rtr, u32 type)
{
struct top_hash_entry **ee = f->hash_table + ospf_top_hash(f, lsa, rtr, type);
struct top_hash_entry *e = *ee;
while (e && (e->lsa_id != lsa || e->rtr_id != rtr || e->lsa_type != type))
e = e->next;
if (e)
return e;
e = sl_alloc(f->hash_slab);
e->lsa_id = lsa;
e->rtr_id = rtr;
e->lsa_type = type;
e->vertex = NULL;
if (f->hash_entries++ > f->hash_entries_max)
ospf_top_rehash(f, HASH_HI_STEP);
return e;
}
void
ospf_hash_delete(struct top_graph *f, struct top_hash_entry *e)
{
unsigned int h = ospf_top_hash(f, e->lsa_id, e->rtr_id, e->lsa_type);
struct top_hash_entry **ee = f->hash_table + h;
while (*ee)
{
if (*ee == e)
{
*ee = e->next;
sl_free(f->hash_slab, e);
if (f->hash_entries-- < f->hash_entries_min)
ospf_top_rehash(f, -HASH_LO_STEP);
return;
}
ee = &((*ee)->next);
}
bug("ospf_hash_delete() called for invalid node");
}
void
ospf_top_dump(struct top_graph *f)
{
unsigned int i;
for(i=0; i<f->hash_size; i++)
{
struct top_hash_entry *e = f->hash_table[i];
while (e)
{
debug("%04x %08x %08x %p\n", e->lsa_type, e->lsa_id, e->rtr_id, e->vertex);
e = e->next;
}
}
}
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