diff options
Diffstat (limited to 'src/cidr.c')
| -rw-r--r-- | src/cidr.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/cidr.c b/src/cidr.c new file mode 100644 index 0000000..d43dabc --- /dev/null +++ b/src/cidr.c @@ -0,0 +1,59 @@ +/* + * (C) 2006-2008 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * 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 + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <stdint.h> +#include <string.h> +#include <netinet/in.h> +#include "cidr.h" + +/* returns the netmask in host byte order */ +uint32_t ipv4_cidr2mask_host(uint8_t cidr) +{ + return 0xFFFFFFFF << (32 - cidr); +} + +/* returns the netmask in network byte order */ +uint32_t ipv4_cidr2mask_net(uint8_t cidr) +{ + return htonl(ipv4_cidr2mask_host(cidr)); +} + +void ipv6_cidr2mask_host(uint8_t cidr, uint32_t *res) +{ + int i, j; + + memset(res, 0, sizeof(uint32_t)*4); + for (i = 0; i < 4 && cidr > 32; i++) { + res[i] = 0xFFFFFFFF; + cidr -= 32; + } + res[i] = 0xFFFFFFFF << (32 - cidr); + for (j = i+1; j < 4; j++) { + res[j] = 0; + } +} + +void ipv6_cidr2mask_net(uint8_t cidr, uint32_t *res) +{ + int i; + + ipv6_cidr2mask_host(cidr, res); + for (i=0; i<4; i++) + res[i] = htonl(res[i]); +} + |