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/* Copyright (C) 2007-2022 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*
* CIDR utility functions
*/
#include "suricata-common.h"
#include "util-cidr.h"
#include "util-debug.h"
#include "util-unittest.h"
/** \brief Turn 32 bit mask into CIDR
*
* \retval cidr The cidr value or -1 if the netmask can't be expressed as cidr
*/
int CIDRFromMask(uint32_t netmask)
{
netmask = ntohl(netmask);
if (netmask == 0) {
return 0;
}
int p = 0;
bool seen_1 = false;
while (netmask > 0) {
if (netmask & 1) {
seen_1 = true;
p++;
} else {
if (seen_1) {
return -1;
}
}
netmask >>= 1;
}
return p;
}
uint32_t CIDRGet(int cidr)
{
if (cidr <= 0 || cidr > 32)
return 0;
uint32_t netmask = htonl(0xFFFFFFFF << (32UL - (uint32_t)cidr));
SCLogDebug("CIDR %d -> netmask %08X", cidr, netmask);
return netmask;
}
/**
* \brief Creates a cidr ipv6 netblock, based on the cidr netblock value.
*
* For example if we send a cidr of 7 as argument, an ipv6 address
* mask of the value FE:00:00:00:00:00:00:00 is created and updated
* in the argument struct in6_addr *in6.
*
* \todo I think for the final section: while (cidr > 0), we can simply
* replace it with a
* if (cidr > 0) {
* in6->s6_addr[i] = -1 << (8 - cidr);
*
* \param cidr The value of the cidr.
* \param in6 Pointer to an ipv6 address structure(struct in6_addr) which will
* hold the cidr netblock result.
*/
void CIDRGetIPv6(int cidr, struct in6_addr *in6)
{
int i = 0;
memset(in6, 0, sizeof(struct in6_addr));
while (cidr > 8) {
in6->s6_addr[i] = 0xff;
cidr -= 8;
i++;
}
while (cidr > 0) {
in6->s6_addr[i] |= 0x80;
if (--cidr > 0)
in6->s6_addr[i] = in6->s6_addr[i] >> 1;
}
}
#ifdef UNITTESTS
static int CIDRFromMaskTest01(void)
{
struct in_addr in;
int v = inet_pton(AF_INET, "255.255.255.0", &in);
FAIL_IF(v <= 0);
FAIL_IF_NOT(24 == CIDRFromMask(in.s_addr));
PASS;
}
static int CIDRFromMaskTest02(void)
{
struct in_addr in;
int v = inet_pton(AF_INET, "255.255.0.42", &in);
FAIL_IF(v <= 0);
FAIL_IF_NOT(-1 == CIDRFromMask(in.s_addr));
PASS;
}
static int CIDRFromMaskTest03(void)
{
struct in_addr in;
int v = inet_pton(AF_INET, "0.0.0.0", &in);
FAIL_IF(v <= 0);
FAIL_IF_NOT(0 == CIDRFromMask(in.s_addr));
PASS;
}
static int CIDRFromMaskTest04(void)
{
struct in_addr in;
int v = inet_pton(AF_INET, "255.255.255.255", &in);
FAIL_IF(v <= 0);
FAIL_IF_NOT(32 == CIDRFromMask(in.s_addr));
PASS;
}
#endif /* UNITTESTS */
void UtilCIDRTests(void)
{
#ifdef UNITTESTS
UtRegisterTest("CIDRFromMaskTest01", CIDRFromMaskTest01);
UtRegisterTest("CIDRFromMaskTest02", CIDRFromMaskTest02);
UtRegisterTest("CIDRFromMaskTest03", CIDRFromMaskTest03);
UtRegisterTest("CIDRFromMaskTest04", CIDRFromMaskTest04);
#endif /* UNITTESTS */
}
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