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/*
* BIRD Internet Routing Daemon -- Network prefix storage
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
* (c) 2022 Maria Matejka <mq@jmq.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _BIRD_LIB_FIB_H_
#define _BIRD_LIB_FIB_H_
/*
* BIRD FIBs are generic data structure for storing network prefixes.
* Also used 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;
struct fib_node {
struct fib_node *next; /* Next in hash chain */
struct fib_iterator *readers; /* List of readers of this node */
net_addr addr[0];
};
struct fib_iterator { /* See lib/slists.h for an explanation */
struct fib_iterator *prev, *next; /* Must be synced with struct fib_node! */
byte efef; /* 0xff to distinguish between iterator and node */
byte pad[3];
struct fib_node *node; /* Or NULL if freshly merged */
uint hash;
};
typedef void (*fib_init_fn)(struct fib *, void *);
struct fib {
pool *fib_pool; /* Pool holding all our data */
slab *fib_slab; /* Slab holding all fib nodes */
struct fib_node **hash_table; /* Node hash table */
uint hash_size; /* Number of hash table entries (a power of two) */
uint hash_order; /* Binary logarithm of hash_size */
uint hash_shift; /* 32 - hash_order */
uint addr_type; /* Type of address data stored in fib (NET_*) */
uint node_size; /* FIB node size, 0 for nonuniform */
uint node_offset; /* Offset of fib_node struct inside of user data */
uint entries; /* Number of entries */
uint entries_min, entries_max; /* Entry count limits (else start rehashing) */
fib_init_fn init; /* Constructor */
};
static inline void * fib_node_to_user(struct fib *f, struct fib_node *e)
{ return e ? (void *) ((char *) e - f->node_offset) : NULL; }
static inline struct fib_node * fib_user_to_node(struct fib *f, void *e)
{ return e ? (void *) ((char *) e + f->node_offset) : NULL; }
void fib_init(struct fib *f, pool *p, uint addr_type, uint node_size, uint node_offset, uint hash_order, fib_init_fn init);
void *fib_find(struct fib *, const net_addr *); /* Find or return NULL if doesn't exist */
void *fib_get_chain(struct fib *f, const net_addr *a); /* Find first node in linked list from hash table */
void *fib_get(struct fib *, const net_addr *); /* Find or create new if nonexistent */
void *fib_route(struct fib *, const net_addr *); /* Longest-match routing lookup */
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 *);
void fit_put_next(struct fib *f, struct fib_iterator *i, struct fib_node *n, uint hpos);
void fit_put_end(struct fib_iterator *i);
void fit_copy(struct fib *f, struct fib_iterator *dst, struct fib_iterator *src);
#define FIB_WALK(fib, type, z) do { \
struct fib_node *fn_, **ff_ = (fib)->hash_table; \
uint count_ = (fib)->hash_size; \
type *z; \
while (count_--) \
for (fn_ = *ff_++; z = fib_node_to_user(fib, fn_); fn_=fn_->next)
#define FIB_WALK_END } while (0)
#define FIB_ITERATE_INIT(it, fib) fit_init(it, fib)
#define FIB_ITERATE_START(fib, it, type, z) do { \
struct fib_node *fn_ = fit_get(fib, it); \
uint count_ = (fib)->hash_size; \
uint hpos_ = (it)->hash; \
type *z; \
for(;;) { \
if (!fn_) \
{ \
if (++hpos_ >= count_) \
break; \
fn_ = (fib)->hash_table[hpos_]; \
continue; \
} \
z = fib_node_to_user(fib, fn_);
#define FIB_ITERATE_END fn_ = fn_->next; } } while(0)
#define FIB_ITERATE_PUT(it) fit_put(it, fn_)
#define FIB_ITERATE_PUT_NEXT(it, fib) fit_put_next(fib, it, fn_, hpos_)
#define FIB_ITERATE_PUT_END(it) fit_put_end(it)
#define FIB_ITERATE_UNLINK(it, fib) fit_get(fib, it)
#define FIB_ITERATE_COPY(dst, src, fib) fit_copy(fib, dst, src)
#endif
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