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/*
* **** License ****
* This program is free software; you can redistribute it and/or modify
* it 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.
* #
* A copy of the GNU General Public License is available as
* `/usr/share/common-licenses/GPL' in the Debian GNU/Linux distribution
* or on the World Wide Web at `http://www.gnu.org/copyleft/gpl.html'.
* You can also obtain it by writing to the Free Software Foundation,
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
* This code was originally developed by Vyatta, Inc.
* Portions created by Vyatta are Copyright (C) 2007 Vyatta, Inc.
* All Rights Reserved.
*
* This code validates IPv4 and IPv6 network prefixes using
* the same rules as the iproute utilities. It is a replacement
* for earlier perl code which did not scale well.
*/
#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
/*
* Note: this code requires full four-tuple when specifying IPv4
* address because the iproute utilites uses a non-standard parsing
* (ie not inet_aton, or inet_pton)
* because of legacy choice to parse 10.8 as 10.8.0.0 not 10.0.0.8
*/
static int valid_ipv4(const char *str)
{
int i;
unsigned int a[4], plen;
uint32_t addr; /* host order */
if (sscanf(str, "%u.%u.%u.%u/%u", &a[0], &a[1], &a[2], &a[3], &plen)
!= 5)
goto bad_addr;
addr = 0;
for (i = 0; i < 4; i++) {
if (a[i] > 255)
goto bad_addr;
addr <<= 8;
addr |= a[i];
}
if (plen == 0 || plen > 32) {
fprintf(stderr,
"Invalid prefix len %d for IP\n", plen);
return 0;
}
if (plen < 31) {
uint32_t net_mask = ~0 << (32 - plen);
uint32_t broadcast = (addr & net_mask) | (~0 &~ net_mask);
if ((addr & net_mask) == addr) {
fprintf(stderr,
"Can not assign network address as IP address\n");
return 0;
}
if (addr == broadcast) {
fprintf(stderr,
"Can not assign broadcast address as IP address\n");
return 0;
}
}
return 1;
bad_addr:
fprintf(stderr, "Invalid IPv4 address/prefix\n");
return 0;
}
static int valid_ipv6(char *str)
{
unsigned int prefix_len;
struct in6_addr addr; /* net order */
char *slash, *endp;
slash = strchr(str, '/');
if (!slash) {
fprintf(stderr, "Missing network prefix\n");
return 0;
}
*slash++ = 0;
prefix_len = strtoul(slash, &endp, 10);
if (*slash == '\0' || *endp != '\0')
fprintf(stderr, "Non-digit in prefix length\n");
else if (prefix_len <= 1 || prefix_len > 128)
fprintf(stderr,
"Invalid prefix len %d for IPv6\n", prefix_len);
else if (inet_pton(AF_INET6, str, &addr) <= 0)
fprintf(stderr, "Invalid IPv6 address\n");
else if (IN6_IS_ADDR_LINKLOCAL(&addr))
fprintf(stderr,
"Can not assign an address reserved for IPv6 link local\n");
else if (IN6_IS_ADDR_MULTICAST(&addr))
fprintf(stderr,
"Can not assign an address reserved for IPv6 multicast\n");
else if (IN6_IS_ADDR_UNSPECIFIED(&addr))
fprintf(stderr,
"Can not assign IPv6 reserved for IPv6 unspecified address\n");
else
return 1; /* is valid address and prefix */
return 0; /* Invalid address */
}
static int valid_prefix(char *str)
{
if (strcmp(str, "dhcp") == 0 || strcmp(str, "dhcpv6") == 0)
return 1;
if (strchr(str, ':') == NULL)
return valid_ipv4(str);
else
return valid_ipv6(str);
}
int main(int argc, char **argv)
{
while (--argc) {
if (!valid_prefix(*++argv))
return 1;
}
return 0;
}
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