fmtip6.c revision 3f54fd611f536639ec30dd53c48e5ec1897cc7d9
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2011 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
#if _PACKAGE_ast
#include <ast.h>
#endif
#include <ip6.h>
#if !_PACKAGE_ast
/*
* return a pointer to n bytes from a circular re-use buffer
*/
static char*
fmtbuf(int n)
{
char* b;
static char buf[1024];
static char* p = buf;
if ((&buf[sizeof(buf)] - p) < n)
p = buf;
b = p;
p += n;
return b;
}
#endif
/*
* copy p to s, then convert 0<=n<=999 to text
* next char in s returned
* caller ensures that s can take strlen(p)+3 bytes
*/
static char*
dec(char* s, char* p, int n)
{
while (*s = *p++)
s++;
if (n >= 100)
*s++ = '0' + ((n / 100) % 10);
if (n >= 10)
*s++ = '0' + ((n / 10) % 10);
*s++ = '0' + (n % 10);
return s;
}
/*
* return pointer to normalized ipv6 address addr
* with optional prefix bits if 0 <= bits <= 128
* return value in short-term circular buffer
*/
char*
fmtip6(const unsigned char* addr, int bits)
{
register const unsigned char* a = addr;
register int n = IP6ADDR;
register int i;
register int z;
register int k;
register int m;
unsigned char r[IP6ADDR];
char* b;
char* s;
static const char dig[] = "0123456789ABCDEF";
s = b = fmtbuf(44);
r[m = z = 0] = 0;
if (a[0] == 0x20 && a[1] == 0x02 && (a[2] || a[3] || a[4] || a[5]))
{
z = 6;
s = dec(s, "2002:", a[2]);
s = dec(s, ".", a[3]);
s = dec(s, ".", a[4]);
s = dec(s, ".", a[5]);
}
for (i = z; i < n; i += 2)
{
for (k = i; i < n - 1 && !a[i] && !a[i + 1]; i += 2);
if ((r[k] = i - k) > r[m] || r[k] == r[m] && i >= (n - 1))
m = k;
}
if (!m)
switch (r[m])
{
case 0:
m = -1;
break;
case 14:
if (!a[14] && a[15] <= 15)
break;
/*FALLTHROUGH*/
case 12:
s = dec(s, "::", a[12]);
s = dec(s, ".", a[13]);
s = dec(s, ".", a[14]);
s = dec(s, ".", a[15]);
n = 0;
break;
case 10:
if (a[10] == 0xFF && a[11] == 0xFF)
{
s = dec(s, "::FFFF:", a[12]);
s = dec(s, ".", a[13]);
s = dec(s, ".", a[14]);
s = dec(s, ".", a[15]);
n = 0;
}
break;
}
for (i = z; i < n; i++)
{
if (i == m)
{
*s++ = ':';
*s++ = ':';
if ((i += r[m]) >= n)
{
z = 1;
break;
}
z = 0;
}
else if (i && !(i & 1))
{
if (z)
z = 0;
else
*s++ = '0';
*s++ = ':';
}
if ((k = (a[i] >> 4) & 0xf) || z)
{
z = 1;
*s++ = dig[k];
}
if ((k = a[i] & 0xf) || z)
{
z = 1;
*s++ = dig[k];
}
}
if (!z && *(s - 1) == ':')
*s++ = '0';
if (bits >= 0 && bits <= 128)
s = dec(s, "/", bits);
*s = 0;
return b;
}