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/**
@file ip6_bit.c
@author Li Minh Bui, feh
@funcs bytetohex, ip6_bitstring, bitstring_ip6, ip6_fmt_str
*/
#include "ip.h"
#include "byte.h"
#include "str.h"
#include "fmt.h"
#include "stralloc.h"
#include "ip_bit.h"
#define BITSUBSTITUTION
/***
/fn bytetohex
/brief Convert a number of max 255 to hex.
/param decimal The decimal number.
/param hex The converted hex value.
*/
void bytetohex(unsigned char decimal, char hex[3])
{
char* hexdigits = "0123456789ABCDEF";
int rest, number;
hex[0] = '0';
hex[1] = '0';
hex[2] = '\0';
number = decimal / 16;
rest = decimal % 16;
hex[0] = hexdigits[number];
hex[1] = hexdigits[rest];
}
static char strnum[FMT_ULONG];
/***
/fn ip6_bitstring
/brief This function converts a IPv6 address into its binary representation.
/param out: ip6string The destination address.
/param in: ip6addr The source address.
/param in: prefix The net prefix bits (maximum 128 bits for IPv6).
/return -1: lack of memory; 1: non valid IPv6 address; 0: successful converted.
*/
int ip6_bitstring(stralloc *ip6string, char *ip6addr, unsigned int prefix)
{
char ip6[16];
int bit, octettbitpos, number, shiftedvalue;
int i, slashpos, ip6len;
#ifdef BITSUBSTITUTION
char subvalueforbitone[1];
subvalueforbitone[0] = 96; /* substitution starts from token '_' = 96 */
#endif
ip6len = str_len(ip6addr);
slashpos = byte_chr(ip6addr,ip6len,'/');
if (!stralloc_copyb(ip6string,ip6addr,slashpos)) return -1;
ip6addr[slashpos] = '\0';
if (!ip6_scan(ip6addr,ip6)) return 1;
if (!stralloc_copys(ip6string,"")) return -1;
for (i = 0; i < 16; i++) {
number = (unsigned char) ip6[i];
for (octettbitpos = 7; octettbitpos >= 0; octettbitpos--) {
shiftedvalue = 1 << octettbitpos;
bit = number / shiftedvalue;
number = number - bit * (shiftedvalue);
if (bit) {
#ifdef BITSUBSTITUTION
if (!stralloc_catb(ip6string,subvalueforbitone,1)) return -1;
subvalueforbitone[0]++;
#else
if (!stralloc_cats(ip6string,"1")) return -1;
#endif
} else
if (!stralloc_cats(ip6string,"0")) return -1;
prefix--;
if (prefix == 0) return 0;
}
}
return 1;
}
/***
/fn bitstring_ip6
/brief This function converts a bit string which is produced by ip6_bitstring()
into an IPv6 address. The string may start with a '^'.
/param in: ip6string Source string which need to be converted.
/param out ip6addr 0-terminated IPv6 destination address with net prefix.
/return -1: No memory could allocated,0: Failure,1: Success.
*/
int bitstring_ip6(stralloc *ip6addr ,stralloc *ip6string)
{
int j = 0;
int i = 0;
int len, prefix, shiftedvalue;
int bitpos = 7;
int decimalnumber = 0;
char ip6[16] = {0};
char ip6compact[40] = {0};
if (!stralloc_copys(ip6addr,"")) return -1;
prefix = ip6string->len - 1;
if (prefix <= 0) return 1;
if (prefix <= 1 || prefix > 128) return 1;
if (ip6string->s[0] == '^') j = 1;
for (i = j, j = 0; i <= prefix; i++) {
if (ip6string->s[i] != '0') {
shiftedvalue = 1 << bitpos;
decimalnumber += shiftedvalue;
}
bitpos--;
if (bitpos == -1) { /* Put each converted byte into the array. */
if (j < 16) {
ip6[j] = (unsigned char) decimalnumber;
j++;
bitpos = 7;
decimalnumber = 0;
}
}
}
if (bitpos < 7) { /* Last bit was read,but the number was not converted. */
ip6[j] = (unsigned char) decimalnumber;
j++;
}
len = ip6_fmt(ip6compact,ip6);
if (!len) return 1;
if (!stralloc_copyb(ip6addr,ip6compact,len)) return -1;
if (!stralloc_cats(ip6addr,"/")) return -1;
if (!stralloc_catb(ip6addr,strnum,fmt_ulong(strnum,prefix))) return -1;
if (!stralloc_0(ip6addr)) return -1;
return 0;
}
/***
/fn ip6_fmt_str
/brief This function expands any valid IPv6 address into its full format of 16 bytes.
It returns the number of processed tokens on success.
/param src Source IPv6 address.
/param destination Expanded IPv6 address.
/return -1: No memory could allocated; 1: failure, 0: success
*/
unsigned int ip6_fmt_str(stralloc *dest, char *src)
{
stralloc addr = {0};
char ip6[16];
char hexvalue[3] = {0, 0, 0};
int i;
if (!stralloc_copys(&addr,src)) return -1;
if (!stralloc_0(&addr)) return -1;
if (ip6_scan(addr.s,ip6) == 0) return 1;
if (!stralloc_copys(dest,"")) return -1;
for (i = 0; i < 16; i++) {
bytetohex((unsigned char)ip6[i],hexvalue);
stralloc_catb(dest,hexvalue,2);
if (!((i+1) % 2) && (i+1) < 16)
if (!stralloc_cats(dest,":")) return -1; /*Append ':' after every two bytes.*/
}
return 0;
}
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