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