1 files changed, 88 insertions, 0 deletions
diff --git a/ip6t_NPTV6_common.h b/ip6t_NPTV6_common.h
new file mode 100644
index 0000000..86b297c
--- /dev/null
+++ b/ip6t_NPTV6_common.h
@@ -0,0 +1,88 @@
+/*
+ * NATv6: IPv6-to-IPv6 Network Prefix Translation as
+ * proposed in RFC 6296.
+ * Based on MAP66 (c) 2010 sven-ola()gmx.de
+ * (c) 2011 mschiffer()universe-factory.net "I'm the one to blame for any problems with this version ;P"
+ */
+
+#ifndef _IP6T_NPTV6_COMMON_H
+#define _IP6T_NPTV6_COMMON_H
+
+#include "ip6t_NPTV6.h"
+#include <net/ipv6.h>
+
+
+#ifndef pr_devel
+#  ifdef DEBUG
+#    define pr_devel(fmt, ...) printk(fmt, ##__VA_ARGS__)
+#  else
+#    define pr_devel(fmt, ...) ({ if (0); })
+#  endif
+#endif
+
+#ifndef NIP6_FMT
+#  define NIP6_FMT "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x"
+#  define NIP6(addr) \
+	ntohs((addr).s6_addr16[0]), \
+	ntohs((addr).s6_addr16[1]), \
+	ntohs((addr).s6_addr16[2]), \
+	ntohs((addr).s6_addr16[3]), \
+	ntohs((addr).s6_addr16[4]), \
+	ntohs((addr).s6_addr16[5]), \
+	ntohs((addr).s6_addr16[6]), \
+	ntohs((addr).s6_addr16[7])
+#endif
+
+
+/* Ones' complement add */
+static inline u_int16_t add16(u_int16_t a, u_int16_t b)
+{
+	a += b;
+	return a + (a < b);
+}
+
+static bool translate_address(struct in6_addr *addr, const struct in6_addr *prefix, u_int16_t plen) {
+	u_int16_t csum = 0;
+	int o = plen / 16, b = plen % 16;
+	int i;
+
+	for (i = 0; i < o; i++) {
+		csum = add16(csum, addr->s6_addr16[i]);
+		csum = add16(csum, ~prefix->s6_addr16[i]);
+
+		addr->s6_addr16[i] = prefix->s6_addr16[i];
+	}
+
+	if (b != 0) {
+		u_int16_t bmask = 0xffff << (16-b);
+		csum = add16(csum, addr->s6_addr16[o] & bmask);
+		csum = add16(csum, ~(prefix->s6_addr16[o] & bmask));
+
+		addr->s6_addr16[o] &= bmask;
+		addr->s6_addr16[o] |= (prefix->s6_addr16[o] & bmask);
+	}
+
+	/* Fix checksum like specified in RFC 6296 */
+	if (plen <= 48) {
+		i = 3;
+	}
+	else {
+		for (i = (plen+15)/16; i < 7; i++) {
+			if (addr->s6_addr16[i] != 0xffff)
+				break;
+		}
+	}
+
+	if (addr->s6_addr16[i] == 0xffff) {
+		return false;
+	}
+
+	addr->s6_addr16[i] = add16(addr->s6_addr16[i], csum);
+	if (addr->s6_addr16[i] == 0xffff) {
+		addr->s6_addr16[i] = 0;
+	}
+
+	return true;
+}
+
+#endif /*_IP6T_NPTV6_COMMON_H*/