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/*
* $Source$
* $Author$
*
* Copyright 1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* For copying and distribution information, please see the file
* <krb5/copyright.h>.
*
* Replay lookaside cache for the KDC, to avoid extra work.
*
*/
#if !defined(lint) && !defined(SABER)
static char rcsid_replay_c[] =
"$Id$";
#endif /* !lint & !SABER */
#include <krb5/krb5.h>
#include <krb5/ext-proto.h>
#include <krb5/libos-proto.h>
#include <krb5/kdb.h>
#include "kdc_util.h"
typedef struct _krb5_kdc_replay_ent {
struct _krb5_kdc_replay_ent *next;
int num_hits;
krb5_int32 timein;
krb5_data *req_packet;
krb5_data *reply_packet;
} krb5_kdc_replay_ent;
static krb5_kdc_replay_ent root_ptr = {0};
static int hits = 0;
static int calls = 0;
static int max_hits_per_entry = 0;
static int num_entries = 0;
#ifndef max
#define max(a,b) (((a) > (b)) ? (a) : (b))
#endif
#define STALE_TIME 2*60 /* two minutes */
#define STALE(ptr) (abs((ptr)->timein - timenow) >= STALE_TIME)
#define MATCH(ptr) (((ptr)->req_packet->length == inpkt->length) && \
!memcmp((ptr)->req_packet->data, inpkt->data, inpkt->length))
/* XXX
Todo: quench the size of the queue...
*/
/* return TRUE if outpkt is filled in with a packet to reply with,
FALSE if the caller should do the work */
krb5_boolean
kdc_check_lookaside(inpkt, outpkt)
register krb5_data *inpkt;
register krb5_data **outpkt;
{
krb5_int32 timenow;
register krb5_kdc_replay_ent *eptr, *last, *hold;
if (krb5_timeofday(&timenow))
return FALSE;
calls++;
/* search for a replay entry in the queue, possibly removing
stale entries while we're here */
if (root_ptr.next) {
for (last = &root_ptr, eptr = root_ptr.next;
eptr;
eptr = eptr->next) {
if (MATCH(eptr)) {
eptr->num_hits++;
hits++;
if (krb5_copy_data(eptr->reply_packet, outpkt))
return FALSE;
else
return TRUE;
/* return here, don't bother flushing even if it is stale.
if we just matched, we may get another retransmit... */
}
if (STALE(eptr)) {
/* flush it and collect stats */
max_hits_per_entry = max(max_hits_per_entry, eptr->num_hits);
krb5_free_data(eptr->req_packet);
krb5_free_data(eptr->reply_packet);
hold = eptr;
last->next = eptr->next;
eptr = last;
xfree(hold);
} else {
/* this isn't it, just move along */
last = eptr;
}
}
}
return FALSE;
}
/* insert a request & reply into the lookaside queue. assumes it's not
already there, and can fail softly due to other weird errors. */
void
kdc_insert_lookaside(inpkt, outpkt)
register krb5_data *inpkt;
register krb5_data *outpkt;
{
register krb5_kdc_replay_ent *eptr;
krb5_int32 timenow;
if (krb5_timeofday(&timenow))
return;
/* this is a new entry */
eptr = (krb5_kdc_replay_ent *)calloc(1, sizeof(*eptr));
if (!eptr)
return;
eptr->timein = timenow;
if (krb5_copy_data(inpkt, &eptr->req_packet)) {
xfree(eptr);
return;
}
if (krb5_copy_data(outpkt, &eptr->reply_packet)) {
krb5_free_data(eptr->req_packet);
xfree(eptr);
return;
}
eptr->next = root_ptr.next;
root_ptr.next = eptr;
num_entries++;
return;
}
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