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-rw-r--r--nest/route.h46
-rw-r--r--nest/rt-fib.c339
2 files changed, 349 insertions, 36 deletions
diff --git a/nest/route.h b/nest/route.h
index d21a32c..da0f1cd 100644
--- a/nest/route.h
+++ b/nest/route.h
@@ -17,21 +17,31 @@ struct proto;
/*
* Generic data structure for storing network prefixes. Also used
- * for the master routing table. Currently implemented as a hash
+ * for the master routing table. Currently implemented as a hash
* table.
*
* Available operations:
* - insertion of new entry
* - deletion of entry
* - searching for entry by network prefix
+ * - asynchronous retrieval of fib contents
*/
struct fib_node {
- ip_addr prefix; /* In host order */
+ struct fib_node *next; /* Next in hash chain */
+ struct fib_iterator *readers; /* List of readers of this node */
byte pxlen;
byte flags; /* User-defined */
byte x0, x1; /* User-defined */
- struct fib_node *next; /* Next in hash chain */
+ ip_addr prefix; /* In host order */
+};
+
+struct fib_iterator { /* See lib/slists.h for an explanation */
+ struct fib_iterator *prev, *next; /* Must be synced with struct fib_node! */
+ struct fib_node *node; /* Or NULL if freshly merged */
+ byte efef; /* 0xff to distinguish between iterator and node */
+ byte pad[3];
+ unsigned int hash;
};
struct fib {
@@ -39,17 +49,23 @@ struct fib {
slab *fib_slab; /* Slab holding all fib nodes */
struct fib_node **hash_table; /* Node hash table */
unsigned int hash_size; /* Number of hash table entries (a power of two) */
- unsigned int hash_mask; /* hash_size - 1 */
+ unsigned int hash_order; /* Binary logarithm of hash_size */
+ unsigned int hash_shift; /* 16 - hash_log */
unsigned int entries; /* Number of entries */
unsigned int entries_min, entries_max;/* Entry count limits (else start rehashing) */
void (*init)(struct fib_node *); /* Constructor */
};
-void fib_init(struct fib *, pool *, unsigned node_size, unsigned hash_size, void (*init)(struct fib_node *));
+void fib_init(struct fib *, pool *, unsigned node_size, unsigned hash_order, void (*init)(struct fib_node *));
void *fib_find(struct fib *, ip_addr *, int); /* Find or return NULL if doesn't exist */
void *fib_get(struct fib *, ip_addr *, int); /* Find or create new if nonexistent */
void fib_delete(struct fib *, void *); /* Remove fib entry */
void fib_free(struct fib *); /* Destroy the fib */
+void fib_check(struct fib *); /* Consistency check for debugging */
+
+void fit_init(struct fib_iterator *, struct fib *); /* Internal functions, don't call */
+struct fib_node *fit_get(struct fib *, struct fib_iterator *);
+void fit_put(struct fib_iterator *, struct fib_node *);
#define FIB_WALK(fib, z) do { \
struct fib_node *z, **ff = (fib)->hash_table; \
@@ -59,6 +75,24 @@ void fib_free(struct fib *); /* Destroy the fib */
#define FIB_WALK_END } while (0)
+#define FIB_ITERATE_INIT(it, fib) fit_init(it, fib)
+
+#define FIB_ITERATE_START(fib, it, z) do { \
+ struct fib_node *z = fit_get(fib, it); \
+ unsigned int count = (fib)->hash_size; \
+ unsigned int hpos = (it)->hash; \
+ for(;;) { \
+ again: if (!z) { \
+ if (++hpos >= count) \
+ break; \
+ z = (fib)->hash_table[hpos]; \
+ goto again; \
+ }
+
+#define FIB_ITERATE_END z = z->next; } } while(0)
+
+#define FIB_ITERATE_PUT(it, z) fit_put(it, z)
+
/*
* Master Routing Tables. Generally speaking, each of them is a list
* of FIB (one per TOS) with each entry pointing to a list of route entries
@@ -76,7 +110,7 @@ typedef struct rtable {
} rtable;
typedef struct network {
- struct fib_node n; /* FIB flags,x0 reserved for kernel syncer */
+ struct fib_node n; /* FIB flags reserved for kernel syncer */
struct rte *routes; /* Available routes for this network */
} net;
diff --git a/nest/rt-fib.c b/nest/rt-fib.c
index 3840712..15db74c 100644
--- a/nest/rt-fib.c
+++ b/nest/rt-fib.c
@@ -13,24 +13,30 @@
#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
+#define HASH_DEF_ORDER 10
+#define HASH_HI_MARK *4
+#define HASH_HI_STEP 2
+#define HASH_HI_MAX 16 /* Must be at most 16 */
+#define HASH_LO_MARK /5
+#define HASH_LO_STEP 2
+#define HASH_LO_MIN 10
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->hash_size = 1 << f->hash_order;
+ f->hash_shift = 16 - f->hash_order;
+ if (f->hash_order > HASH_HI_MAX - HASH_HI_STEP)
+ f->entries_max = ~0;
+ else
+ f->entries_max = f->hash_size HASH_HI_MARK;
+ if (f->hash_order < HASH_LO_MIN + HASH_LO_STEP)
f->entries_min = 0;
- DBG("Allocating FIB: %d entries, %d low, %d high\n", f->hash_size, f->entries_min, f->entries_max);
+ else
+ f->entries_min = f->hash_size HASH_LO_MARK;
+ DBG("Allocating FIB hash of order %d: %d entries, %d low, %d high\n",
+ f->hash_order, 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
@@ -42,46 +48,64 @@ fib_ht_free(struct fib_node **h)
static inline unsigned
fib_hash(struct fib *f, ip_addr *a)
{
- return ipa_hash(*a) & f->hash_mask;
+ return ipa_hash(*a) >> f->hash_shift;
}
void
-fib_init(struct fib *f, pool *p, unsigned node_size, unsigned hash_size, void (*init)(struct fib_node *))
+fib_init(struct fib *f, pool *p, unsigned node_size, unsigned hash_order, void (*init)(struct fib_node *))
{
- if (!hash_size)
- hash_size = HASH_DEF_SIZE;
+ if (!hash_order)
+ hash_order = HASH_DEF_ORDER;
f->fib_pool = p;
f->fib_slab = sl_new(p, node_size);
- f->hash_size = hash_size;
+ f->hash_order = hash_order;
fib_ht_alloc(f);
+ bzero(f->hash_table, f->hash_size * sizeof(struct fib_node *));
f->entries = 0;
f->entries_min = 0;
f->init = init;
}
static void
-fib_rehash(struct fib *f, unsigned new)
+fib_rehash(struct fib *f, int step)
{
- unsigned old;
+ unsigned old, new, oldn, newn, ni, nh;
struct fib_node **n, *e, *x, **t, **m, **h;
- old = f->hash_size;
+ old = f->hash_order;
+ oldn = f->hash_size;
+ new = old + step;
m = h = f->hash_table;
- DBG("Re-hashing FIB from %d to %d\n", old, new);
- f->hash_size = new;
+ DBG("Re-hashing FIB from order %d to %d\n", old, new);
+ f->hash_order = new;
fib_ht_alloc(f);
- n = f->hash_table;
+ t = n = f->hash_table;
+ newn = f->hash_size;
+ ni = 0;
+
while (old--)
{
x = *h++;
while (e = x)
{
x = e->next;
- t = n + fib_hash(f, &e->prefix);
- e->next = *t;
+ nh = fib_hash(f, &e->prefix);
+ while (nh > ni)
+ {
+ *t = NULL;
+ ni++;
+ t = ++n;
+ }
*t = e;
+ t = &e->next;
}
}
+ while (ni < newn)
+ {
+ *t = NULL;
+ ni++;
+ t = ++n;
+ }
fib_ht_free(m);
}
@@ -98,8 +122,9 @@ fib_find(struct fib *f, ip_addr *a, int len)
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;
+ unsigned int h = ipa_hash(*a);
+ struct fib_node **ee = f->hash_table + (h >> f->hash_shift);
+ struct fib_node *g, *e = *ee;
while (e && (e->pxlen != len || !ipa_equal(*a, e->prefix)))
e = e->next;
@@ -112,28 +137,80 @@ fib_get(struct fib *f, ip_addr *a, int len)
e = sl_alloc(f->fib_slab);
e->prefix = *a;
e->pxlen = len;
+ while ((g = *ee) && ipa_hash(g->prefix) < h)
+ ee = &g->next;
e->next = *ee;
*ee = e;
+ e->readers = NULL;
f->init(e);
if (f->entries++ > f->entries_max)
- fib_rehash(f, f->hash_size HASH_HI_RESIZE);
+ fib_rehash(f, HASH_HI_STEP);
return e;
}
+static inline void
+fib_merge_readers(struct fib_iterator *i, struct fib_node *to)
+{
+ if (to)
+ {
+ struct fib_iterator *j = to->readers;
+ if (!j)
+ {
+ /* Fast path */
+ to->readers = i;
+ i->prev = (struct fib_iterator *) to;
+ fixup:
+ while (i && i->node)
+ {
+ i->node = NULL;
+ i = i->next;
+ }
+ return;
+ }
+ /* Really merging */
+ while (j->next)
+ j = j->next;
+ j->next = i;
+ i->prev = j;
+ goto fixup;
+ }
+ else /* No more nodes */
+ while (i)
+ {
+ i->prev = NULL;
+ i = i->next;
+ }
+}
+
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);
+ unsigned int h = fib_hash(f, &e->prefix);
+ struct fib_node **ee = f->hash_table + h;
+ struct fib_iterator *it;
while (*ee)
{
if (*ee == e)
{
*ee = e->next;
+ if (it = e->readers)
+ {
+ struct fib_node *l = e->next;
+ while (!l)
+ {
+ h++;
+ if (h >= f->hash_size)
+ break;
+ else
+ l = f->hash_table[h];
+ }
+ fib_merge_readers(it, l);
+ }
sl_free(f->fib_slab, e);
if (f->entries-- < f->entries_min)
- fib_rehash(f, f->hash_size HASH_LO_RESIZE);
+ fib_rehash(f, -HASH_LO_STEP);
return;
}
ee = &((*ee)->next);
@@ -147,3 +224,205 @@ fib_free(struct fib *f)
fib_ht_free(f->hash_table);
rfree(f->fib_slab);
}
+
+void
+fit_init(struct fib_iterator *i, struct fib *f)
+{
+ unsigned h;
+ struct fib_node *n;
+
+ i->efef = 0xff;
+ for(h=0; h<f->hash_size; h++)
+ if (n = f->hash_table[h])
+ {
+ i->prev = (struct fib_iterator *) n;
+ if (i->next = n->readers)
+ i->next->prev = i;
+ n->readers = i;
+ i->node = n;
+ return;
+ }
+ /* The fib is empty, nothing to do */
+ i->prev = i->next = NULL;
+ i->node = NULL;
+}
+
+struct fib_node *
+fit_get(struct fib *f, struct fib_iterator *i)
+{
+ struct fib_node *n;
+ struct fib_iterator *j, *k;
+
+ if (!i->prev)
+ {
+ /* We are at the end */
+ i->hash = f->hash_size;
+ return NULL;
+ }
+ if (!(n = i->node))
+ {
+ /* No node info available, we are a victim of merging. Try harder. */
+ j = i;
+ while (j->efef == 0xff)
+ j = j->prev;
+ n = (struct fib_node *) j;
+ }
+ j = i->prev;
+ if (k = i->next)
+ k->prev = j;
+ j->next = k;
+ i->hash = fib_hash(f, &n->prefix);
+ return n;
+}
+
+void
+fit_put(struct fib_iterator *i, struct fib_node *n)
+{
+ struct fib_iterator *j;
+
+ i->node = n;
+ if (j = n->readers)
+ j->prev = i;
+ i->next = j;
+ n->readers = i;
+ i->prev = (struct fib_iterator *) n;
+}
+
+#ifdef DEBUGGING
+
+void
+fib_check(struct fib *f)
+{
+ unsigned int i, ec, lo, nulls;
+
+ ec = 0;
+ for(i=0; i<f->hash_size; i++)
+ {
+ struct fib_node *n;
+ lo = 0;
+ for(n=f->hash_table[i]; n; n=n->next)
+ {
+ struct fib_iterator *j, *j0;
+ unsigned int h0 = ipa_hash(n->prefix);
+ if (h0 < lo)
+ die("fib_check: discord in hash chains");
+ lo = h0;
+ if ((h0 >> f->hash_shift) != i)
+ die("fib_check: mishashed %x->%x (order %d)", h0, i, f->hash_order);
+ j0 = (struct fib_iterator *) n;
+ nulls = 0;
+ for(j=n->readers; j; j=j->next)
+ {
+ if (j->prev != j0)
+ die("fib_check: iterator->prev mismatch");
+ j0 = j;
+ if (!j->node)
+ nulls++;
+ else if (nulls)
+ die("fib_check: iterator nullified");
+ else if (j->node != n)
+ die("fib_check: iterator->node mismatch");
+ }
+ ec++;
+ }
+ }
+ if (ec != f->entries)
+ die("fib_check: invalid entry count (%d != %d)", ec, f->entries);
+}
+
+#endif
+
+#ifdef TEST
+
+#include "lib/resource.h"
+
+struct fib f;
+
+void dump(char *m)
+{
+ unsigned int i;
+
+ debug("%s ... order=%d, size=%d, entries=%d\n", m, f.hash_order, f.hash_size, f.hash_size);
+ for(i=0; i<f.hash_size; i++)
+ {
+ struct fib_node *n;
+ struct fib_iterator *j;
+ for(n=f.hash_table[i]; n; n=n->next)
+ {
+ debug("%04x %04x %p %I/%2d", i, ipa_hash(n->prefix), n, n->prefix, n->pxlen);
+ for(j=n->readers; j; j=j->next)
+ debug(" %p[%p]", j, j->node);
+ debug("\n");
+ }
+ }
+ fib_check(&f);
+ debug("-----\n");
+}
+
+void init(struct fib_node *n)
+{
+}
+
+int main(void)
+{
+ struct fib_node *n;
+ struct fib_iterator i, j;
+ ip_addr a;
+ int c;
+
+ log_init_debug(NULL);
+ resource_init();
+ fib_init(&f, &root_pool, sizeof(struct fib_node), 4, init);
+ dump("init");
+
+ a = ipa_from_u32(0x01020304); n = fib_get(&f, &a, 32);
+ a = ipa_from_u32(0x02030405); n = fib_get(&f, &a, 32);
+ a = ipa_from_u32(0x03040506); n = fib_get(&f, &a, 32);
+ a = ipa_from_u32(0x00000000); n = fib_get(&f, &a, 32);
+ a = ipa_from_u32(0x00000c01); n = fib_get(&f, &a, 32);
+ a = ipa_from_u32(0xffffffff); n = fib_get(&f, &a, 32);
+ dump("fill");
+
+ fit_init(&i, &f);
+ dump("iter init");
+
+ fib_rehash(&f, 1);
+ dump("rehash up");
+
+ fib_rehash(&f, -1);
+ dump("rehash down");
+
+next:
+ c = 0;
+ FIB_ITERATE_START(&f, &i, z)
+ {
+ if (c)
+ {
+ FIB_ITERATE_PUT(&i, z);
+ dump("iter");
+ goto next;
+ }
+ c = 1;
+ debug("got %p\n", z);
+ }
+ FIB_ITERATE_END;
+ dump("iter end");
+
+ fit_init(&i, &f);
+ fit_init(&j, &f);
+ dump("iter init 2");
+
+ n = fit_get(&f, &i);
+ dump("iter step 2");
+
+ fit_put(&i, n->next);
+ dump("iter step 3");
+
+ a = ipa_from_u32(0xffffffff); n = fib_get(&f, &a, 32);
+ fib_delete(&f, n);
+ dump("iter step 3");
+
+ return 0;
+}
+
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 10:26:44 +0100