util_ordering.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Copyright 1993 by OpenVision Technologies, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appears in all copies and
* that both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of OpenVision not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. OpenVision makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, 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.
*/
/*
* $Id: util_ordering.c,v 1.4 1996/10/21 20:17:11 tytso Exp $
*/
/*
* functions to check sequence numbers for replay and sequencing
*/
#include <mechglueP.h>
#include <gssapiP_generic.h>
#define QUEUE_LENGTH 20
typedef struct _queue {
int do_replay;
int do_sequence;
int start;
int length;
gssint_uint64 firstnum;
gssint_uint64 elem[QUEUE_LENGTH];
gssint_uint64 mask;
} queue;
/* rep invariant:
* - the queue is a circular queue. The first element (q->elem[q->start])
* is the oldest. The last element is the newest.
*/
#define QSIZE(q) (sizeof((q)->elem)/sizeof((q)->elem[0]))
#define QELEM(q,i) ((q)->elem[(i)%QSIZE(q)])
static void
queue_insert(queue *q, int after, gssint_uint64 seqnum)
{
/* insert. this is not the fastest way, but it's easy, and it's
optimized for insert at end, which is the common case */
int i;
/* common case: at end, after == q->start+q->length-1 */
/* move all the elements (after,last] up one slot */
for (i=q->start+q->length-1; i>after; i--)
QELEM(q,i+1) = QELEM(q,i);
/* fill in slot after+1 */
QELEM(q,after+1) = seqnum;
/* Either increase the length by one, or move the starting point up
one (deleting the first element, which got bashed above), as
appropriate. */
if (q->length == QSIZE(q)) {
q->start++;
if (q->start == QSIZE(q))
q->start = 0;
} else {
q->length++;
}
}
gss_int32
g_order_init(void **vqueue, gssint_uint64 seqnum,
int do_replay, int do_sequence, int wide_nums)
{
queue *q;
if ((q = (queue *) MALLOC(sizeof(queue))) == NULL)
return(ENOMEM);
q->do_replay = do_replay;
q->do_sequence = do_sequence;
q->mask = wide_nums ? ~(gssint_uint64)0 : 0xffffffffUL;
q->start = 0;
q->length = 1;
q->firstnum = seqnum;
q->elem[q->start] = ((gssint_uint64)0 - 1) & q->mask;
*vqueue = (void *) q;
return(0);
}
gss_int32
g_order_check(void **vqueue, gssint_uint64 seqnum)
{
queue *q;
int i;
gssint_uint64 expected;
q = (queue *) (*vqueue);
if (!q->do_replay && !q->do_sequence)
return(GSS_S_COMPLETE);
/* All checks are done relative to the initial sequence number, to
avoid (or at least put off) the pain of wrapping. */
/* wraparound case */
if (seqnum < q->firstnum) {
/* if 32 bit, put seqnum into 64 bit range */
if (q->mask != ~(gssint_uint64)0) {
seqnum |= 0x100000000ULL;
seqnum -= q->firstnum;
} else {
/*
* 64 bit wraparound, just add the number of
* elements before the wraparound point
* to get the normalized seqnum.
*/
seqnum += (~(gssint_uint64)0) - q->firstnum;
}
} else {
/*
* Normally (as long as seqnum >= firstnum), just subtract
* the firstnum to get the relative 'seqnum'.
*/
seqnum -= q->firstnum;
}
/* rule 1: expected sequence number */
expected = (QELEM(q,q->start+q->length-1)+1) & q->mask;
if (seqnum == expected) {
queue_insert(q, q->start+q->length-1, seqnum);
return(GSS_S_COMPLETE);
}
/* rule 2: > expected sequence number */
if ((seqnum > expected)) {
queue_insert(q, q->start+q->length-1, seqnum);
if (q->do_replay && !q->do_sequence)
return(GSS_S_COMPLETE);
else
return(GSS_S_GAP_TOKEN);
}
/* rule 3: seqnum < seqnum(first) */
if (seqnum < QELEM(q,q->start)) {
if (q->do_replay)
return(GSS_S_OLD_TOKEN);
else
return(GSS_S_UNSEQ_TOKEN);
}
/* rule 4+5: seqnum in [seqnum(first),seqnum(last)] */
else {
if (seqnum == QELEM(q,q->start+q->length-1))
return(GSS_S_DUPLICATE_TOKEN);
for (i=q->start; i<q->start+q->length-1; i++) {
if (seqnum == QELEM(q,i))
return(GSS_S_DUPLICATE_TOKEN);
if ((seqnum > QELEM(q,i)) && (seqnum < QELEM(q,i+1))) {
queue_insert(q, i, seqnum);
if (q->do_replay && !q->do_sequence)
return(GSS_S_COMPLETE);
else
return(GSS_S_UNSEQ_TOKEN);
}
}
}
/* this should never happen */
return(GSS_S_FAILURE);
}
void
g_order_free(void **vqueue)
{
queue *q;
q = (queue *) (*vqueue);
FREE (q, sizeof (queue));
*vqueue = NULL;
}
/*
* These support functions are for the serialization routines
*/
/*ARGSUSED*/
gss_uint32
g_queue_size(void *vqueue, size_t *sizep)
{
*sizep += sizeof(queue);
return 0;
}
gss_uint32
g_queue_externalize(void *vqueue, unsigned char **buf, size_t *lenremain)
{
(void) memcpy(*buf, vqueue, sizeof(queue));
*buf += sizeof(queue);
*lenremain -= sizeof(queue);
return 0;
}
gss_uint32
g_queue_internalize(void **vqueue, unsigned char **buf, size_t *lenremain)
{
void *q;
if ((q = (void *) MALLOC(sizeof(queue))) == 0)
return ENOMEM;
(void) memcpy(q, *buf, sizeof(queue));
*buf += sizeof(queue);
*lenremain -= sizeof(queue);
*vqueue = q;
return 0;
}