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/*
* 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
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
# define xt_action_param xt_target_param
# define CHECKENTRY_RET bool
# define CHECKENTRY_RET_SUCCESS true
# define CHECKENTRY_RET_EINVAL false
#else
# define CHECKENTRY_RET int
# define CHECKENTRY_RET_SUCCESS 0
# define CHECKENTRY_RET_EINVAL (-EINVAL)
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,34)
# define icmpv6_send(skb, type, code, info) icmpv6_send(skb, type, code, info, NULL)
#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 fix_word;
int i;
/* Fix checksum like specified in RFC 6296 */
if (plen <= 48) {
fix_word = 3;
}
else {
for (fix_word = 4; fix_word < 7; fix_word++) {
if (addr->s6_addr16[fix_word] != 0xffff)
break;
}
}
if (addr->s6_addr16[fix_word] == 0xffff) {
/* Fail before the address is translated so the ICMP error can be sent */
return false;
}
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 = htons(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);
}
addr->s6_addr16[fix_word] = add16(addr->s6_addr16[fix_word], csum);
if (addr->s6_addr16[fix_word] == 0xffff) {
addr->s6_addr16[fix_word] = 0;
}
return true;
}
#endif /*_IP6T_NPTV6_COMMON_H*/
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