1 files changed, 70 insertions, 0 deletions
diff --git a/src/cidr.c b/src/cidr.c
new file mode 100644
index 0000000..91025b6
--- /dev/null
+++ b/src/cidr.c
@@ -0,0 +1,70 @@
+/*
+ * (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]);
+}
+
+/* I need this function because I initially defined an IPv6 address as
+ * uint32 u[4]. Using char u[16] instead would allow to remove this. */
+void ipv6_addr2addr_host(uint32_t *addr, uint32_t *res)
+{
+	int i;
+
+	memset(res, 0, sizeof(uint32_t)*4);
+	for (i = 0;  i < 4; i++) {
+		res[i] = ntohl(addr[i]);
+	}
+}