nsz Git - musl/blob - src/network/inet_ntop.c

   1 #include <sys/socket.h>
   2 #include <netinet/in.h>
   3 #include <arpa/inet.h>
   4 #include <netdb.h>
   5 #include <errno.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8
   9 const char *inet_ntop(int af, const void *restrict a0, char *restrict s, socklen_t l)
  10 {
  11         const unsigned char *a = a0;
  12         int i, j, max, best;
  13         char buf[100];
  14
  15         switch (af) {
  16         case AF_INET:
  17                 if (snprintf(s, l, "%d.%d.%d.%d", a[0],a[1],a[2],a[3]) < l)
  18                         return s;
  19                 break;
  20         case AF_INET6:
  21                 if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\377\377", 12))
  22                         snprintf(buf, sizeof buf,
  23                                 "%x:%x:%x:%x:%x:%x:%x:%x",
  24                                 256*a[0]+a[1],256*a[2]+a[3],
  25                                 256*a[4]+a[5],256*a[6]+a[7],
  26                                 256*a[8]+a[9],256*a[10]+a[11],
  27                                 256*a[12]+a[13],256*a[14]+a[15]);
  28                 else
  29                         snprintf(buf, sizeof buf,
  30                                 "%x:%x:%x:%x:%x:%x:%d.%d.%d.%d",
  31                                 256*a[0]+a[1],256*a[2]+a[3],
  32                                 256*a[4]+a[5],256*a[6]+a[7],
  33                                 256*a[8]+a[9],256*a[10]+a[11],
  34                                 a[12],a[13],a[14],a[15]);
  35                 /* Replace longest /(^0|:)[:0]{2,}/ with "::" */
  36                 for (i=best=0, max=2; buf[i]; i++) {
  37                         if (i && buf[i] != ':') continue;
  38                         j = strspn(buf+i, ":0");
  39                         if (j>max) best=i, max=j;
  40                 }
  41                 if (max>2) {
  42                         buf[best] = buf[best+1] = ':';
  43                         memmove(buf+best+2, buf+best+max, i-best-max+1);
  44                 }
  45                 if (strlen(buf) < l) {
  46                         strcpy(s, buf);
  47                         return s;
  48                 }
  49                 break;
  50         default:
  51                 errno = EAFNOSUPPORT;
  52                 return 0;
  53         }
  54         errno = ENOSPC;
  55         return 0;
  56 }