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/* ISC license. */
#include <stdint.h>
#include <skalibs/uint16.h>
#include <skalibs/fmtscan.h>
/* IPv6 scanner
class | 0 1 2 3
st\ev | other hex : .
START | m
00 | X LIMB COLON1 X
COLON1 | p
01 | X X NEW X
NEW | m
02 | END LIMB X X
LIMB | h h
03 | END LIMB COLON V4
COLON | m p
04 | X LIMB NEW X
END = 05
V4 = 06
X = 07
0x10 m mark
0x20 p set doublecolon pos
0x40 h scan hex, next limb
*/
size_t ip6_scan (char const *s, char *ip6)
{
static unsigned char const class[256] = "0000000000000000000000000000000000000000000000301111111111200000011111100000000000000000000000000111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000" ;
static uint8_t const table[5][4] =
{
{ 0x07, 0x13, 0x01, 0x07 },
{ 0x07, 0x07, 0x22, 0x07 },
{ 0x05, 0x13, 0x07, 0x07 },
{ 0x45, 0x03, 0x44, 0x06 },
{ 0x07, 0x13, 0x22, 0x07 }
} ;
size_t i = 0, mark = 0 ;
uint16_t limb[8] = { 0, 0, 0, 0, 0, 0, 0, 0 } ;
uint8_t pos = 8, j = 0, state = 0 ;
for (; state < 0x05 ; i++)
{
uint8_t c = table[state][class[(unsigned char)s[i]] - '0'] ;
state = c & 0x07 ;
if (c & 0x10) mark = i ;
if (c & 0x20) { if (pos < 8) state = 0x07 ; else pos = j ; }
if (c & 0x40)
if (j >= 8 || uint16_xscan(s + mark, limb + j++) != i - mark) state = 0x07 ;
}
switch (state)
{
case 0x05:
if (pos == 8 && j < 8 || (pos < 8 && j > 6)) return 0 ;
i-- ;
break ;
case 0x06:
{
uint32_t ip4 ;
if (pos == 8 && j != 6 || (pos < 8 && j > 4)) return 0 ;
i = ip4_scanu32(s + mark, &ip4) ;
if (!i) return 0 ;
limb[j++] = ip4 >> 16 ;
limb[j++] = ip4 & 0xffff ;
i += mark ;
break ;
}
default : return 0 ;
}
for (state = j ; state > pos ; state--) limb[state - j + 7] = limb[state - 1] ;
for (; state < pos + 8 - j ; state++) limb[state] = 0 ;
for (j = 0 ; j < 8 ; j++) uint16_pack_big(ip6 + (j<<1), limb[j]) ;
return i ;
}
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