curl/lib/inet_ntop.c

210 lines
4.8 KiB
C

/*
* Original code by Paul Vixie. "curlified" by Gisle Vanem.
*/
#include "setup.h"
#ifndef HAVE_INET_NTOP
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include <string.h>
#include <errno.h>
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#include "inet_ntop.h"
#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
/* this platform has a inet_ntoa_r() function, but no proto declared anywhere
so we include our own proto to make compilers happy */
#include "inet_ntoa_r.h"
#endif
#define IN6ADDRSZ 16
#define INADDRSZ 4
#define INT16SZ 2
#ifdef WIN32
#define EAFNOSUPPORT WSAEAFNOSUPPORT
#define SET_ERRNO(e) WSASetLastError(errno = (e))
#else
#define SET_ERRNO(e) errno = e
#endif
/*
* Format an IPv4 address, more or less like inet_ntoa().
*
* Returns `dst' (as a const)
* Note:
* - uses no statics
* - takes a u_char* not an in_addr as input
*/
static const char *inet_ntop4 (const u_char *src, char *dst, size_t size)
{
#if defined(HAVE_INET_NTOA_R_2_ARGS)
const char *ptr;
size_t len;
curlassert(size >= 16);
ptr = inet_ntoa_r(*(struct in_addr*)src, dst);
len = strlen(ptr);
memmove(dst, ptr, len);
dst[len] = 0;
return dst;
#elif defined(HAVE_INET_NTOA_R)
return inet_ntoa_r(*(struct in_addr*)src, dst, size);
#else
const char *addr = inet_ntoa(*(struct in_addr*)src);
if (strlen(addr) >= size)
{
SET_ERRNO(ENOSPC);
return (NULL);
}
return strcpy(dst, addr);
#endif
}
#ifdef ENABLE_IPV6
/*
* Convert IPv6 binary address into presentation (printable) format.
*/
static const char *inet_ntop6 (const u_char *src, char *dst, size_t size)
{
/*
* Note that int32_t and int16_t need only be "at least" large enough
* to contain a value of the specified size. On some systems, like
* Crays, there is no such thing as an integer variable with 16 bits.
* Keep this in mind if you think this function should have been coded
* to use pointer overlays. All the world's not a VAX.
*/
char tmp [sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
char *tp;
struct {
long base;
long len;
} best, cur;
u_long words [IN6ADDRSZ / INT16SZ];
int i;
/* Preprocess:
* Copy the input (bytewise) array into a wordwise array.
* Find the longest run of 0x00's in src[] for :: shorthanding.
*/
memset(words, 0, sizeof(words));
for (i = 0; i < IN6ADDRSZ; i++)
words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
best.base = -1;
cur.base = -1;
for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
{
if (words[i] == 0)
{
if (cur.base == -1)
cur.base = i, cur.len = 1;
else
cur.len++;
}
else if (cur.base != -1)
{
if (best.base == -1 || cur.len > best.len)
best = cur;
cur.base = -1;
}
}
if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
best = cur;
if (best.base != -1 && best.len < 2)
best.base = -1;
/* Format the result.
*/
tp = tmp;
for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
{
/* Are we inside the best run of 0x00's?
*/
if (best.base != -1 && i >= best.base && i < (best.base + best.len))
{
if (i == best.base)
*tp++ = ':';
continue;
}
/* Are we following an initial run of 0x00s or any real hex?
*/
if (i != 0)
*tp++ = ':';
/* Is this address an encapsulated IPv4?
*/
if (i == 6 && best.base == 0 &&
(best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
{
if (!inet_ntop4(src+12, tp, sizeof(tmp) - (tp - tmp)))
{
SET_ERRNO(ENOSPC);
return (NULL);
}
tp += strlen(tp);
break;
}
tp += snprintf(tp, 5, "%lx", words[i]);
}
/* Was it a trailing run of 0x00's?
*/
if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
*tp++ = ':';
*tp++ = '\0';
/* Check for overflow, copy, and we're done.
*/
if ((size_t)(tp - tmp) > size)
{
SET_ERRNO(ENOSPC);
return (NULL);
}
return strcpy (dst, tmp);
}
#endif /* ENABLE_IPV6 */
/*
* Convert a network format address to presentation format.
*
* Returns pointer to presentation format address (`dst'),
* Returns NULL on error (see errno).
*/
const char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size)
{
switch (af) {
case AF_INET:
return inet_ntop4((const u_char*)src, buf, size);
#ifdef ENABLE_IPV6
case AF_INET6:
return inet_ntop6((const u_char*)src, buf, size);
#endif
default:
SET_ERRNO(EAFNOSUPPORT);
return NULL;
}
}
#endif /* HAVE_INET_NTOP */