#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#define MAX_V4_ADDR_LEN 16
#define MAX_V6_ADDR_LEN 64
static const char *hexchars = "0123456789abcdef";
const char * inet_ntop6(const struct in6_addr *addr, char *dst, socklen_t size);
const char * inet_ntop4(const struct in_addr *addr, char *dst, socklen_t size);
const char *
inet_ntop(int af, const void *addr, char *buf, socklen_t len)
{
if (af == AF_INET6) return inet_ntop6(addr, buf, len);
if (af == AF_INET) return inet_ntop4(addr, buf, len);
errno = EAFNOSUPPORT;
return NULL;
}
const char *
inet_ntop6(const struct in6_addr *addr, char *dst, socklen_t size)
{
char hexa[8][5], tmp[MAX_V6_ADDR_LEN];
int zr[8];
socklen_t len;
int32_t i, j, k, skip;
uint8_t x8, hx8;
uint16_t x16;
struct in_addr a4;
if (addr == NULL)
{
errno = EAFNOSUPPORT;
return NULL;
}
if (dst == NULL)
{
errno = ENOSPC;
return NULL;
}
memset(tmp, 0, MAX_V6_ADDR_LEN);
i = IN6_IS_ADDR_V4MAPPED(addr);
j = IN6_IS_ADDR_V4COMPAT(addr);
if ((i != 0) || (j != 0))
{
const char *prefix;
socklen_t prefix_len;
if (i != 0) {
prefix = "::ffff:";
prefix_len = 7;
} else {
prefix = "::";
prefix_len = 2;
}
a4.s_addr = addr->__u6_addr.__u6_addr32[3];
inet_ntop4(&a4, tmp, sizeof(tmp));
len = strlen(tmp) + 1;
if (prefix_len + len > size)
{
errno = ENOSPC;
return NULL;
}
memcpy(dst, prefix, prefix_len);
memcpy(dst + prefix_len, tmp, len);
return dst;
}
k = 0;
for (i = 0; i < 16; i += 2)
{
j = 0;
skip = 1;
memset(hexa[k], 0, 5);
x8 = addr->__u6_addr.__u6_addr8[i];
hx8 = x8 >> 4;
if (hx8 != 0)
{
skip = 0;
hexa[k][j++] = hexchars[hx8];
}
hx8 = x8 & 0x0f;
if ((skip == 0) || ((skip == 1) && (hx8 != 0)))
{
skip = 0;
hexa[k][j++] = hexchars[hx8];
}
x8 = addr->__u6_addr.__u6_addr8[i + 1];
hx8 = x8 >> 4;
if ((skip == 0) || ((skip == 1) && (hx8 != 0)))
{
hexa[k][j++] = hexchars[hx8];
}
hx8 = x8 & 0x0f;
hexa[k][j++] = hexchars[hx8];
k++;
}
j = 0;
for (i = 7; i >= 0; i--)
{
zr[i] = j;
x16 = addr->__u6_addr.__u6_addr16[i];
if (x16 == 0) j++;
else j = 0;
zr[i] = j;
}
k = -1;
j = 0;
for(i = 0; i < 8; i++)
{
if (zr[i] > j)
{
k = i;
j = zr[i];
}
}
for(i = 0; i < 8; i++)
{
if (i != k) zr[i] = 0;
}
len = 0;
for (i = 0; i < 8; i++)
{
if (zr[i] != 0)
{
if (i == 0) tmp[len++] = ':';
tmp[len++] = ':';
i += (zr[i] - 1);
continue;
}
for (j = 0; hexa[i][j] != '\0'; j++) tmp[len++] = hexa[i][j];
if (i != 7) tmp[len++] = ':';
}
len++;
if (len > size)
{
errno = ENOSPC;
return NULL;
}
memcpy(dst, tmp, len);
return dst;
}
const char *
inet_ntop4(const struct in_addr *addr, char *dst, socklen_t size)
{
char tmp[MAX_V4_ADDR_LEN], *p;
const u_int8_t *ap = (u_int8_t *)&addr->s_addr;
int i, ql, len;
if (addr == NULL)
{
errno = EAFNOSUPPORT;
return NULL;
}
if (dst == NULL)
{
errno = ENOSPC;
return NULL;
}
memset(tmp, 0, MAX_V4_ADDR_LEN);
len = 4;
p = tmp;
for (i = 0; i < 4; i++, ap++)
{
snprintf(p, 4, "%d", *ap);
ql = strlen(p);
len += ql;
p += ql;
if (i < 3) *p++ = '.';
}
if (len > size)
{
errno = ENOSPC;
return NULL;
}
memcpy(dst, tmp, len);
return dst;
}