inet_pton.c raw

   1  #include <sys/socket.h>
   2  #include <arpa/inet.h>
   3  #include <ctype.h>
   4  #include <errno.h>
   5  #include <string.h>
   6  
   7  static 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  
  15  int 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