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/* $OpenBSD: rde_prefix.c,v 1.6 2004/01/06 10:51:14 claudio Exp $ */
/*
* Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <errno.h>
#include <stdlib.h>
#include "bgpd.h"
#include "ensure.h"
#include "rde.h"
/*
* Prefix Table functions:
* pt_add: create new prefix and link it into the prefix table
* pt_remove: Checks if there is no bgp prefix linked to the prefix,
* unlinks form the prefix table and frees the pt_entry.
* pt_get: get a prefix/prefixlen entry. While pt_lookup searches for the
* best matching prefix pt_get only finds the prefix/prefixlen
* entry. The speed of pt_get is important for the bgp updates.
* pt_lookup: lookup a IP in the prefix table. Manly for "show ip bgp".
* pt_empty: returns true if there is no bgp prefix linked to the pt_entry.
* pt_init: initialize prefix table.
* pt_alloc: allocate a pt_entry. Internal function.
* pt_free: free a pt_entry. Internal function.
*/
/* internal prototypes */
static struct pt_entry *pt_alloc(void);
static void pt_free(struct pt_entry *);
/*
* currently we are using a hash list to store the prefixes. This may be
* replaced with a red-black trie if necessary.
*/
LIST_HEAD(pt_entryhead, pt_entry);
struct pt_table {
struct pt_entryhead *pt_hashtbl;
u_long pt_hashmask;
};
#define MIN_PREFIX 0
#define MAX_PREFIX 32
/*
* size of the hashtable per prefixlen. The sizes were chosen from a bgp
* dump done on Nov 4. 2003.
*/
u_long pthashsize[MAX_PREFIX + 1 - MIN_PREFIX] = {
/* need to be power of 2 */
1, 1, 1, 1, 1, 1, 1, 1,
16, 8, 8, 16, 32, 64, 256, 256,
4096, 1024, 2048, 8192, 8192, 4096, 8192, 8192,
32768, 1, 1, 1, 1, 1, 1, 1, 1
};
struct pt_table pttable[MAX_PREFIX + 1 - MIN_PREFIX];
#define PT_HASH(p, plen) \
&pttable[plen].pt_hashtbl[((p >> plen) ^ (p >> (plen + 5))) & pttable[plen].pt_hashmask]
/*
* Statistics collector.
* Collected to tune the prefix table. Currently only a few counters were
* added. More to come as soon as we see where we are going.
* TODO: add a function that dumps the stats after a specified period of time.
*/
struct pt_stats {
u_int64_t pt_alloc;
u_int64_t pt_free;
u_int64_t pt_add[MAX_PREFIX + 1 - MIN_PREFIX];
u_int64_t pt_get[MAX_PREFIX + 1 - MIN_PREFIX];
u_int64_t pt_remove[MAX_PREFIX + 1 - MIN_PREFIX];
u_int64_t pt_lookup;
u_int64_t pt_dump;
} ptstats;
/* simple macros to update statistics */
#define PT_STAT(x) (ptstats.x++)
#define PT_STAT2(x, p) (ptstats.x[p]++)
void
pt_init(void)
{
int i;
u_long j;
for (i = MIN_PREFIX; i <= MAX_PREFIX; i++) {
pttable[i].pt_hashtbl = calloc(pthashsize[i],
sizeof(struct pt_entryhead));
if (pttable[i].pt_hashtbl == NULL)
fatal("pt_init");
for (j = 0; j < pthashsize[i]; j++)
LIST_INIT(&pttable[i].pt_hashtbl[j]);
pttable[i].pt_hashmask = pthashsize[i] - 1;
}
}
int
pt_empty(struct pt_entry *pte)
{
ENSURE(pte != NULL);
return LIST_EMPTY(&pte->prefix_h);
}
struct pt_entry *
pt_get(struct in_addr prefix, int prefixlen)
{
struct pt_entryhead *head;
struct pt_entry *p;
u_int32_t p_hbo;
ENSURE(MIN_PREFIX <= prefixlen && prefixlen <= MAX_PREFIX);
PT_STAT2(pt_get, prefixlen);
p_hbo = ntohl(prefix.s_addr);
head = PT_HASH(p_hbo, prefixlen);
ENSURE(head != NULL);
LIST_FOREACH(p, head, pt_l) {
if (prefix.s_addr == p->prefix.s_addr)
return p;
}
return NULL;
}
struct pt_entry *
pt_add(struct in_addr prefix, int prefixlen)
{
struct pt_entryhead *head;
struct pt_entry *p;
u_int32_t p_hbo;
ENSURE(MIN_PREFIX <= prefixlen && prefixlen <= MAX_PREFIX);
ENSURE(pt_get(prefix, prefixlen) == NULL);
PT_STAT2(pt_add, prefixlen);
p_hbo = ntohl(prefix.s_addr);
head = PT_HASH(p_hbo, prefixlen);
ENSURE(head != NULL);
p = pt_alloc();
p->prefix = prefix;
p->prefixlen = prefixlen;
LIST_INIT(&p->prefix_h);
LIST_INSERT_HEAD(head, p, pt_l);
return p;
}
void
pt_remove(struct pt_entry *pte)
{
ENSURE(pt_empty(pte));
PT_STAT2(pt_remove, pte->prefixlen);
LIST_REMOVE(pte, pt_l);
/* XXX we could bzero it for debugging reasons */
pt_free(pte);
}
struct pt_entry *
pt_lookup(struct in_addr prefix)
{
struct pt_entry *p;
int i;
PT_STAT(pt_lookup);
for (i = MAX_PREFIX; i >= MIN_PREFIX; i--) {
p = pt_get(prefix, i);
if (p != NULL)
return p;
}
return NULL;
}
/*
* XXX We need a redblack tree to get an ordered output.
* XXX A nicer upcall interface wouldn't be luxus too.
*/
void
pt_dump(void (*upcall)(struct pt_entry *, void *), void *arg)
{
struct pt_entry *p;
int i;
u_long j;
PT_STAT(pt_dump);
for (i = MAX_PREFIX; i >= MIN_PREFIX; i--) {
for (j = 0; j < pthashsize[i]; j++)
LIST_FOREACH(p, &pttable[i].pt_hashtbl[j], pt_l)
upcall(p, arg);
}
}
/* returns a zeroed pt_entry function may not return on fail */
static struct pt_entry *
pt_alloc(void)
{
struct pt_entry *p;
PT_STAT(pt_alloc);
p = calloc(1, sizeof(*p));
if (p == NULL)
fatal("pt_alloc");
return p;
}
static void
pt_free(struct pt_entry *pte)
{
PT_STAT(pt_free);
free(pte);
}
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