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