1#include <sys/socket.h>
2#include <arpa/inet.h>
3#include <ctype.h>
4#include <errno.h>
5#include <string.h>
6
7#if __GNUC__ < 4
8#define restrict
9#endif
10
11static int hexval(unsigned c)
12{
13	if (c-'0'<10) return c-'0';
14	c |= 32;
15	if (c-'a'<6) return c-'a'+10;
16	return -1;
17}
18
19int inet_pton(int af, const char *restrict s, void *restrict a0)
20{
21	uint16_t ip[8];
22	unsigned char *a = a0;
23	int i, j, v, d, brk=-1, need_v4=0;
24
25	if (af==AF_INET) {
26		for (i=0; i<4; i++) {
27			for (v=j=0; j<3 && isdigit(s[j]); j++)
28				v = 10*v + s[j]-'0';
29			if (j==0 || (j>1 && s[0]=='0') || v>255) return 0;
30			a[i] = v;
31			if (s[j]==0 && i==3) return 1;
32			if (s[j]!='.') return 0;
33			s += j+1;
34		}
35		return 0;
36	} else if (af!=AF_INET6) {
37		errno = EAFNOSUPPORT;
38		return -1;
39	}
40
41	if (*s==':' && *++s!=':') return 0;
42
43	for (i=0; ; i++) {
44		if (s[0]==':' && brk<0) {
45			brk=i;
46			ip[i&7]=0;
47			if (!*++s) break;
48			if (i==7) return 0;
49			continue;
50		}
51		for (v=j=0; j<4 && (d=hexval(s[j]))>=0; j++)
52			v=16*v+d;
53		if (j==0) return 0;
54		ip[i&7] = v;
55		if (!s[j] && (brk>=0 || i==7)) break;
56		if (i==7) return 0;
57		if (s[j]!=':') {
58			if (s[j]!='.' || (i<6 && brk<0)) return 0;
59			need_v4=1;
60			i++;
61			break;
62		}
63		s += j+1;
64	}
65	if (brk>=0) {
66		memmove(ip+brk+7-i, ip+brk, 2*(i+1-brk));
67		for (j=0; j<7-i; j++) ip[brk+j] = 0;
68	}
69	for (j=0; j<8; j++) {
70		*a++ = ip[j]>>8;
71		*a++ = ip[j];
72	}
73	if (need_v4 && inet_pton(AF_INET, (void *)s, a-4) <= 0) return 0;
74	return 1;
75}
76