inet_ntop.c
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上传日期:2007-10-30
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- /* Id: inet_ntop.c,v 1.4 2001/04/17 07:53:47 lukem Exp */
- /* $NetBSD: inet_ntop.c,v 1.9 2000/01/22 22:19:16 mycroft Exp $ */
- /* Copyright (c) 1996 by Internet Software Consortium.
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
- * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
- * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
- * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
- * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
- * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
- * SOFTWARE.
- */
- #include <net-snmp/net-snmp-config.h>
- #ifndef HAVE_INET_NTOP
- #if HAVE_ARPA_NAMESER_H
- #include <arpa/nameser.h>
- #endif
- /*
- * Net-SNMP Win32 additions
- */
- #if defined(HAVE_WINSOCK_H) || defined(cygwin)
- #include <winsock2.h>
- #include <ws2tcpip.h>
- #include <errno.h>
- #include <stdio.h>
- #endif
- #ifndef EAFNOSUPPORT
- #define EAFNOSUPPORT WSAEAFNOSUPPORT
- #endif
- /*
- * End of Net-SNMP Win32 additions
- */
- #ifndef IN6ADDRSZ
- #define IN6ADDRSZ 16
- #endif
- #ifndef INT16SZ
- #define INT16SZ 2
- #endif
- #ifdef SPRINTF_CHAR
- # define SPRINTF(x) strlen(sprintf/**/x)
- #else
- # define SPRINTF(x) ((size_t)sprintf x)
- #endif
- /*
- * WARNING: Don't even consider trying to compile this on a system where
- * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
- */
- static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
- #ifdef INET6
- static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
- #endif /* INET6 */
- /* char *
- * inet_ntop(af, src, dst, size)
- * convert a network format address to presentation format.
- * return:
- * pointer to presentation format address (`dst'), or NULL (see errno).
- * author:
- * Paul Vixie, 1996.
- */
- const char *
- inet_ntop(af, src, dst, size)
- int af;
- const void *src;
- char *dst;
- size_t size;
- {
- switch (af) {
- case AF_INET:
- return (inet_ntop4(src, dst, size));
- #ifdef INET6
- case AF_INET6:
- return (inet_ntop6(src, dst, size));
- #endif
- default:
- errno = EAFNOSUPPORT;
- return (NULL);
- }
- /* NOTREACHED */
- }
- /* const char *
- * inet_ntop4(src, dst, size)
- * format an IPv4 address, more or less like inet_ntoa()
- * return:
- * `dst' (as a const)
- * notes:
- * (1) uses no statics
- * (2) takes a u_char* not an in_addr as input
- * author:
- * Paul Vixie, 1996.
- */
- static const char *
- inet_ntop4(src, dst, size)
- const u_char *src;
- char *dst;
- size_t size;
- {
- static const char fmt[] = "%u.%u.%u.%u";
- char tmp[sizeof "255.255.255.255"];
- if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
- errno = ENOSPC;
- return (NULL);
- }
- strcpy(dst, tmp);
- return (dst);
- }
- #ifdef INET6
- /* const char *
- * inet_ntop6(src, dst, size)
- * convert IPv6 binary address into presentation (printable) format
- * author:
- * Paul Vixie, 1996.
- */
- static const char *
- inet_ntop6(src, dst, size)
- 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"], *tp;
- struct { int base, len; } best, cur;
- u_int 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, ' ', 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) {
- if (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)))
- return (NULL);
- tp += strlen(tp);
- break;
- }
- tp += SPRINTF((tp, "%x", words[i]));
- }
- /* Was it a trailing run of 0x00's? */
- if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
- *tp++ = ':';
- *tp++ = ' ';
- /*
- * Check for overflow, copy, and we're done.
- */
- if ((size_t)(tp - tmp) > size) {
- errno = ENOSPC;
- return (NULL);
- }
- strcpy(dst, tmp);
- return (dst);
- }
- #endif
- #endif /* HAVE_INET_NTOP */