1#include <sys/socket.h> 2#include <arpa/inet.h> 3#include <errno.h> 4#include <stdio.h> 5#include <string.h> 6 7const char *inet_ntop(int af, const void *restrict a0, char *restrict s, socklen_t l) 8{ 9 const unsigned char *a = a0; 10 int i, j, max, best; 11 char buf[100]; 12 13 switch (af) { 14 case AF_INET: 15 if (snprintf(s, l, "%d.%d.%d.%d", a[0],a[1],a[2],a[3]) < l) 16 return s; 17 break; 18 case AF_INET6: 19 if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\377\377", 12)) 20 snprintf(buf, sizeof buf, 21 "%x:%x:%x:%x:%x:%x:%x:%x", 22 256*a[0]+a[1],256*a[2]+a[3], 23 256*a[4]+a[5],256*a[6]+a[7], 24 256*a[8]+a[9],256*a[10]+a[11], 25 256*a[12]+a[13],256*a[14]+a[15]); 26 else 27 snprintf(buf, sizeof buf, 28 "%x:%x:%x:%x:%x:%x:%d.%d.%d.%d", 29 256*a[0]+a[1],256*a[2]+a[3], 30 256*a[4]+a[5],256*a[6]+a[7], 31 256*a[8]+a[9],256*a[10]+a[11], 32 a[12],a[13],a[14],a[15]); 33 /* Replace longest /(^0|:)[:0]{2,}/ with "::" */ 34 for (i=best=0, max=2; buf[i]; i++) { 35 if (i && buf[i] != ':') continue; 36 j = strspn(buf+i, ":0"); 37 if (j>max) best=i, max=j; 38 } 39 if (max>2) { 40 buf[best] = buf[best+1] = ':'; 41 memmove(buf+best+2, buf+best+max, i-best-max+1); 42 } 43 if (strlen(buf) < l) { 44 strcpy(s, buf); 45 return s; 46 } 47 break; 48 default: 49 errno = EAFNOSUPPORT; 50 return 0; 51 } 52 errno = ENOSPC; 53 return 0; 54} 55