static int inet_pton4(const char *src, u_char *dst);
static int inet_pton6(const char *src, u_char *dst);
/* int
* inet_pton(af, src, dst)
* convert from presentation format (which usually means ASCII printable)
* to network format (which is usually some kind of binary format).
* return:
* 1 if the address was valid for the specified address family
* 0 if the address wasn't valid (`dst' is untouched in this case)
* -1 if some other error occurred (`dst' is untouched in this case, too)
* author:
* Paul Vixie, 1996.
*/
int
inet_pton(int af, const char *src, void *dst)
{
switch (af) {
case AF_INET:
return (inet_pton4(src, dst));
case AF_INET6:
return (inet_pton6(src, dst));
default:
errno = EAFNOSUPPORT;
return (-1);
}
/* NOTREACHED */
}
/* int
* inet_pton4(src, dst)
* like inet_aton() but without all the hexadecimal and shorthand.
* return:
* 1 if `src' is a valid dotted quad, else 0.
* notice:
* does not touch `dst' unless it's returning 1.
* author:
* Paul Vixie, 1996.
*/
static int
inet_pton4(const char *src, u_char *dst)
{
static const char digits[] = "0123456789";
int saw_digit, octets, ch;
u_char tmp[INADDRSZ], *tp;
saw_digit = 0;
octets = 0;
*(tp = tmp) = 0;
while ((ch = *src++) != '\0') {
const char *pch;
if ((pch = strchr(digits, ch)) != NULL) {
u_int new = *tp * 10 + (pch - digits);//**可以通过指针直接获取某一项的值
if (new > 255)
return (0);
if (! saw_digit) {
if (++octets > 4)
return (0);
saw_digit = 1;
}
*tp = new;
} else if (ch == '.' && saw_digit) {
if (octets == 4)
return (0);
*++tp = 0;
saw_digit = 0;
} else
return (0);
}
if (octets < 4)
return (0);
memcpy(dst, tmp, INADDRSZ);
return (1);
}
/* int
* inet_pton6(src, dst)
* convert presentation level address to network order binary form.
* return:
* 1 if `src' is a valid [RFC1884 2.2] address, else 0.
* notice:
* (1) does not touch `dst' unless it's returning 1.
* (2) :: in a full address is silently ignored.
* credit:
* inspired by Mark Andrews.
* author:
* Paul Vixie, 1996.
*/
static int
inet_pton6(const char *src, u_char *dst)
{
static const char xdigits_l[] = "0123456789abcdef",
xdigits_u[] = "0123456789ABCDEF";
u_char tmp[IN6ADDRSZ], *tp, *endp, *colonp;
const char *xdigits, *curtok;
int ch, saw_xdigit, count_xdigit;
u_int val;
memset((tp = tmp), '\0', IN6ADDRSZ);
endp = tp + IN6ADDRSZ;
colonp = NULL;
/* Leading :: requires some special handling. */
if (*src == ':')
if (*++src != ':')
return (0);
curtok = src;
saw_xdigit = count_xdigit = 0;
val = 0;
while ((ch = *src++) != '\0') {
const char *pch;
if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
pch = strchr((xdigits = xdigits_u), ch);
if (pch != NULL) {
if (count_xdigit >= 4)
return (0);
val <<= 4;
val |= (pch - xdigits);
if (val > 0xffff)
return (0);
saw_xdigit = 1;
count_xdigit++;
continue;
}
if (ch == ':') {
curtok = src;
if (!saw_xdigit) {
if (colonp)
return (0);
colonp = tp;
continue;
} else if (*src == '\0') {
return (0);
}
if (tp + INT16SZ > endp)
return (0);
*tp++ = (u_char) (val >> 8) & 0xff;
*tp++ = (u_char) val & 0xff;
saw_xdigit = 0;
count_xdigit = 0;
val = 0;
continue;
}
if (ch == '.' && ((tp + INADDRSZ) <= endp) &&
inet_pton4(curtok, tp) > 0) {
tp += INADDRSZ;
saw_xdigit = 0;
count_xdigit = 0;
break; /* '\0' was seen by inet_pton4(). */
}
return (0);
}
if (saw_xdigit) {
if (tp + INT16SZ > endp)
return (0);
*tp++ = (u_char) (val >> 8) & 0xff;
*tp++ = (u_char) val & 0xff;
}
if (colonp != NULL) {
/*
* Since some memmove()'s erroneously fail to handle
* overlapping regions, we'll do the shift by hand.
*/
const int n = tp - colonp;
int i;
for (i = 1; i <= n; i++) {
endp[- i] = colonp[n - i];
colonp[n - i] = 0;
}
tp = endp;
}
if (tp != endp)
return (0);
memcpy(dst, tmp, IN6ADDRSZ);
return (1);
}
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