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/*
* Copyright 1997 Massachusetts Institute of Technology
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that both the above copyright notice and this
* permission notice appear in all copies, that both the above
* copyright notice and this permission notice appear in all
* supporting documentation, and that the name of M.I.T. not be used
* in advertising or publicity pertaining to distribution of the
* software without specific, written prior permission. M.I.T. makes
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied
* warranty.
*
* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: hostcache.c,v 1.2 1997/10/12 20:25:06 phk Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <net/hostcache.h>
#include <net/route.h>
MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "per-host cache structure");
static struct hctable hctable[AF_MAX];
static int hc_timeout_interval = 120;
static int hc_maxidle = 1800;
static int cmpsa(const struct sockaddr *sa1, const struct sockaddr *sa2);
static void hc_timeout(void *xhct);
static void maybe_bump_hash(struct hctable *hct);
int
hc_init(int af, struct hccallback *hccb, int init_nelem, int primes)
{
struct hctable *hct;
struct hchead *heads;
u_long nelem;
hct = &hctable[af];
nelem = init_nelem;
if (hct->hct_nentries)
return 0;
if (primes) {
heads = phashinit(init_nelem, M_HOSTCACHE, &nelem);
} else {
int i;
MALLOC(heads, struct hchead *, nelem * sizeof *heads,
M_HOSTCACHE, M_WAITOK);
for (i = 0; i < nelem; i++) {
LIST_INIT(&heads[i]);
}
}
hct->hct_heads = heads;
hct->hct_nentries = nelem;
hct->hct_primes = primes;
timeout(hc_timeout, hct, hc_timeout_interval * hz);
return 0;
}
struct hcentry *
hc_get(struct sockaddr *sa)
{
u_long hash;
struct hcentry *hc;
struct hctable *hct;
int s;
hct = &hctable[sa->sa_family];
if (hct->hct_nentries == 0)
return 0;
hash = hct->hct_cb->hccb_hash(sa, hct->hct_nentries);
hc = hct->hct_heads[hash].lh_first;
for (; hc; hc = hc->hc_link.le_next) {
if (cmpsa(hc->hc_host, sa) == 0)
break;
}
if (hc == 0)
return 0;
s = splnet();
if (hc->hc_rt && (hc->hc_rt->rt_flags & RTF_UP) == 0) {
RTFREE(hc->hc_rt);
hc->hc_rt = 0;
}
if (hc->hc_rt == 0) {
hc->hc_rt = rtalloc1(hc->hc_host, 1, 0);
}
hc_ref(hc);
splx(s);
/* XXX move to front of list? */
return hc;
}
void
hc_ref(struct hcentry *hc)
{
int s = splnet();
if (hc->hc_refcnt++ == 0) {
hc->hc_hct->hct_idle--;
hc->hc_hct->hct_active++;
}
splx(s);
}
void
hc_rele(struct hcentry *hc)
{
int s = splnet();
#ifdef DIAGNOSTIC
printf("hc_rele: %p: negative refcnt!\n", (void *)hc);
#endif
hc->hc_refcnt--;
if (hc->hc_refcnt == 0) {
hc->hc_hct->hct_idle++;
hc->hc_hct->hct_active--;
hc->hc_idlesince = mono_time; /* XXX right one? */
}
splx(s);
}
/*
* The user is expected to initialize hc_host with the address and everything
* else to the appropriate form of `0'.
*/
int
hc_insert(struct hcentry *hc)
{
struct hcentry *hc2;
struct hctable *hct;
u_long hash;
int s;
hct = &hctable[hc->hc_host->sa_family];
hash = hct->hct_cb->hccb_hash(hc->hc_host, hct->hct_nentries);
hc2 = hct->hct_heads[hash].lh_first;
for (; hc2; hc2 = hc2->hc_link.le_next) {
if (cmpsa(hc2->hc_host, hc->hc_host) == 0)
break;
}
if (hc2 != 0)
return EEXIST;
hc->hc_hct = hct;
s = splnet();
LIST_INSERT_HEAD(&hct->hct_heads[hash], hc, hc_link);
hct->hct_idle++;
/*
* If the table is now more than 75% full, consider bumping it.
*/
if (100 * (hct->hct_idle + hct->hct_active) > 75 * hct->hct_nentries)
maybe_bump_hash(hct);
splx(s);
return 0;
}
/*
* It's not clear to me how much sense this makes as an external interface,
* since it is expected that the deletion will normally be handled by
* the cache timeout.
*/
int
hc_delete(struct hcentry *hc)
{
struct hctable *hct;
int error, s;
if (hc->hc_refcnt > 0)
return 0;
hct = hc->hc_hct;
error = hct->hct_cb->hccb_delete(hc);
if (error)
return 0;
s = splnet();
LIST_REMOVE(hc, hc_link);
hc->hc_hct->hct_idle--;
splx(s);
FREE(hc, M_HOSTCACHE);
return 0;
}
static void
hc_timeout(void *xhct)
{
struct hcentry *hc;
struct hctable *hct;
int j, s;
time_t start;
hct = xhct;
start = mono_time.tv_sec; /* for simplicity */
if (hct->hct_idle == 0)
return;
for (j = 0; j < hct->hct_nentries; j++) {
for (hc = hct->hct_heads[j].lh_first; hc;
hc = hc->hc_link.le_next) {
if (hc->hc_refcnt > 0)
continue;
if (hc->hc_idlesince.tv_sec + hc_maxidle <= start) {
if (hct->hct_cb->hccb_delete(hc))
continue;
s = splnet();
LIST_REMOVE(hc, hc_link);
hct->hct_idle--;
splx(s);
}
}
}
/*
* Fiddle something here based on tot_idle...
*/
timeout(hc_timeout, xhct, hc_timeout_interval * hz);
}
static int
cmpsa(const struct sockaddr *sa1, const struct sockaddr *sa2)
{
if (sa1->sa_len != sa2->sa_len)
return ((int)sa1->sa_len - sa2->sa_len);
return bcmp(sa1, sa2, sa1->sa_len);
}
static void
maybe_bump_hash(struct hctable *hct)
{
; /* XXX fill me in */
}
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