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/*
* comparisons
* Copyright (C) 2000 Henry Spencer.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/lgpl.txt>.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
* License for more details.
*
* RCSID $Id: sameaddr.c,v 1.1 2004/03/15 20:35:26 as Exp $
*/
#include "internal.h"
#include "freeswan.h"
static int samenbits(const ip_address *a, const ip_address *b, int n);
/*
- addrcmp - compare two addresses
* Caution, the order of the tests is subtle: doing type test before
* size test can yield cases where a<b, b<c, but a>c.
*/
int /* like memcmp */
addrcmp(a, b)
const ip_address *a;
const ip_address *b;
{
int at = addrtypeof(a);
int bt = addrtypeof(b);
const unsigned char *ap;
const unsigned char *bp;
size_t as = addrbytesptr(a, &ap);
size_t bs = addrbytesptr(b, &bp);
size_t n = (as < bs) ? as : bs; /* min(as, bs) */
int c = memcmp(ap, bp, n);
if (c != 0) /* bytes differ */
return (c < 0) ? -1 : 1;
if (as != bs) /* comparison incomplete: lexical order */
return (as < bs) ? -1 : 1;
if (at != bt) /* bytes same but not same type: break tie */
return (at < bt) ? -1 : 1;
return 0;
}
/*
- sameaddr - are two addresses the same?
*/
int
sameaddr(a, b)
const ip_address *a;
const ip_address *b;
{
return (addrcmp(a, b) == 0) ? 1 : 0;
}
/*
- samesubnet - are two subnets the same?
*/
int
samesubnet(a, b)
const ip_subnet *a;
const ip_subnet *b;
{
if (!sameaddr(&a->addr, &b->addr)) /* also does type check */
return 0;
if (a->maskbits != b->maskbits)
return 0;
return 1;
}
/*
- subnetishost - is a subnet in fact a single host?
*/
int
subnetishost(a)
const ip_subnet *a;
{
return (a->maskbits == addrlenof(&a->addr)*8) ? 1 : 0;
}
/*
- samesaid - are two SA IDs the same?
*/
int
samesaid(a, b)
const ip_said *a;
const ip_said *b;
{
if (a->spi != b->spi) /* test first, most likely to be different */
return 0;
if (!sameaddr(&a->dst, &b->dst))
return 0;
if (a->proto != b->proto)
return 0;
return 1;
}
/*
- sameaddrtype - do two addresses have the same type?
*/
int
sameaddrtype(a, b)
const ip_address *a;
const ip_address *b;
{
return (addrtypeof(a) == addrtypeof(b)) ? 1 : 0;
}
/*
- samesubnettype - do two subnets have the same type?
*/
int
samesubnettype(a, b)
const ip_subnet *a;
const ip_subnet *b;
{
return (subnettypeof(a) == subnettypeof(b)) ? 1 : 0;
}
/*
- addrinsubnet - is this address in this subnet?
*/
int
addrinsubnet(a, s)
const ip_address *a;
const ip_subnet *s;
{
if (addrtypeof(a) != subnettypeof(s))
return 0;
if (!samenbits(a, &s->addr, s->maskbits))
return 0;
return 1;
}
/*
- subnetinsubnet - is one subnet within another?
*/
int
subnetinsubnet(a, b)
const ip_subnet *a;
const ip_subnet *b;
{
if (subnettypeof(a) != subnettypeof(b))
return 0;
if (a->maskbits < b->maskbits) /* a is bigger than b */
return 0;
if (!samenbits(&a->addr, &b->addr, b->maskbits))
return 0;
return 1;
}
/*
- samenbits - do two addresses have the same first n bits?
*/
static int
samenbits(a, b, nbits)
const ip_address *a;
const ip_address *b;
int nbits;
{
const unsigned char *ap;
const unsigned char *bp;
size_t n;
int m;
if (addrtypeof(a) != addrtypeof(b))
return 0; /* arbitrary */
n = addrbytesptr(a, &ap);
if (n == 0)
return 0; /* arbitrary */
(void) addrbytesptr(b, &bp);
if (nbits > n*8)
return 0; /* "can't happen" */
for (; nbits >= 8 && *ap == *bp; nbits -= 8, ap++, bp++)
continue;
if (nbits >= 8)
return 0;
if (nbits > 0) { /* partial byte */
m = ~(0xff >> nbits);
if ((*ap & m) != (*bp & m))
return 0;
}
return 1;
}
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