1/* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */ 2 3/* Copyright (c) 1996 by Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 10 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 11 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 12 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 13 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 14 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 15 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 16 * SOFTWARE. 17 */ 18 19#include "includes.h" 20 21#ifndef HAVE_INET_NTOP 22 23#if defined(LIBC_SCCS) && !defined(lint) 24#if 0 25static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $"; 26#else 27static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $"; 28#endif 29#endif /* LIBC_SCCS and not lint */ 30 31#include <sys/param.h> 32#include <sys/types.h> 33#include <sys/socket.h> 34#include "fake-socket.h" 35#include <netinet/in.h> 36#include <arpa/inet.h> 37#ifndef HAVE_CYGWIN 38#include <arpa/nameser.h> 39#endif 40#include <string.h> 41#include <errno.h> 42#include <stdio.h> 43 44#ifndef IN6ADDRSZ 45#define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 46#endif 47 48#ifndef INT16SZ 49#define INT16SZ 2 /* for systems without 16-bit ints */ 50#endif 51 52/* 53 * WARNING: Don't even consider trying to compile this on a system where 54 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 55 */ 56 57static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 58static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 59 60/* char * 61 * inet_ntop(af, src, dst, size) 62 * convert a network format address to presentation format. 63 * return: 64 * pointer to presentation format address (`dst'), or NULL (see errno). 65 * author: 66 * Paul Vixie, 1996. 67 */ 68const char * 69inet_ntop(af, src, dst, size) 70 int af; 71 const void *src; 72 char *dst; 73 size_t size; 74{ 75 switch (af) { 76 case AF_INET: 77 return (inet_ntop4(src, dst, size)); 78 case AF_INET6: 79 return (inet_ntop6(src, dst, size)); 80 default: 81 errno = EAFNOSUPPORT; 82 return (NULL); 83 } 84 /* NOTREACHED */ 85} 86 87/* const char * 88 * inet_ntop4(src, dst, size) 89 * format an IPv4 address, more or less like inet_ntoa() 90 * return: 91 * `dst' (as a const) 92 * notes: 93 * (1) uses no statics 94 * (2) takes a u_char* not an in_addr as input 95 * author: 96 * Paul Vixie, 1996. 97 */ 98static const char * 99inet_ntop4(src, dst, size) 100 const u_char *src; 101 char *dst; 102 size_t size; 103{ 104 static const char fmt[] = "%u.%u.%u.%u"; 105 char tmp[sizeof "255.255.255.255"]; 106 int l; 107 108 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]); 109 if (l <= 0 || l >= size) { 110 errno = ENOSPC; 111 return (NULL); 112 } 113 strlcpy(dst, tmp, size); 114 return (dst); 115} 116 117/* const char * 118 * inet_ntop6(src, dst, size) 119 * convert IPv6 binary address into presentation (printable) format 120 * author: 121 * Paul Vixie, 1996. 122 */ 123static const char * 124inet_ntop6(src, dst, size) 125 const u_char *src; 126 char *dst; 127 size_t size; 128{ 129 /* 130 * Note that int32_t and int16_t need only be "at least" large enough 131 * to contain a value of the specified size. On some systems, like 132 * Crays, there is no such thing as an integer variable with 16 bits. 133 * Keep this in mind if you think this function should have been coded 134 * to use pointer overlays. All the world's not a VAX. 135 */ 136 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"]; 137 char *tp, *ep; 138 struct { int base, len; } best, cur; 139 u_int words[IN6ADDRSZ / INT16SZ]; 140 int i; 141 int advance; 142 143 /* 144 * Preprocess: 145 * Copy the input (bytewise) array into a wordwise array. 146 * Find the longest run of 0x00's in src[] for :: shorthanding. 147 */ 148 memset(words, '\0', sizeof words); 149 for (i = 0; i < IN6ADDRSZ; i++) 150 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 151 best.base = -1; 152 cur.base = -1; 153 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 154 if (words[i] == 0) { 155 if (cur.base == -1) 156 cur.base = i, cur.len = 1; 157 else 158 cur.len++; 159 } else { 160 if (cur.base != -1) { 161 if (best.base == -1 || cur.len > best.len) 162 best = cur; 163 cur.base = -1; 164 } 165 } 166 } 167 if (cur.base != -1) { 168 if (best.base == -1 || cur.len > best.len) 169 best = cur; 170 } 171 if (best.base != -1 && best.len < 2) 172 best.base = -1; 173 174 /* 175 * Format the result. 176 */ 177 tp = tmp; 178 ep = tmp + sizeof(tmp); 179 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) { 180 /* Are we inside the best run of 0x00's? */ 181 if (best.base != -1 && i >= best.base && 182 i < (best.base + best.len)) { 183 if (i == best.base) { 184 if (tp + 1 >= ep) 185 return (NULL); 186 *tp++ = ':'; 187 } 188 continue; 189 } 190 /* Are we following an initial run of 0x00s or any real hex? */ 191 if (i != 0) { 192 if (tp + 1 >= ep) 193 return (NULL); 194 *tp++ = ':'; 195 } 196 /* Is this address an encapsulated IPv4? */ 197 if (i == 6 && best.base == 0 && 198 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 199 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp))) 200 return (NULL); 201 tp += strlen(tp); 202 break; 203 } 204 advance = snprintf(tp, ep - tp, "%x", words[i]); 205 if (advance <= 0 || advance >= ep - tp) 206 return (NULL); 207 tp += advance; 208 } 209 /* Was it a trailing run of 0x00's? */ 210 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) { 211 if (tp + 1 >= ep) 212 return (NULL); 213 *tp++ = ':'; 214 } 215 if (tp + 1 >= ep) 216 return (NULL); 217 *tp++ = '\0'; 218 219 /* 220 * Check for overflow, copy, and we're done. 221 */ 222 if ((size_t)(tp - tmp) > size) { 223 errno = ENOSPC; 224 return (NULL); 225 } 226 strlcpy(dst, tmp, size); 227 return (dst); 228} 229 230#endif /* !HAVE_INET_NTOP */ 231 232#pragma ident "%Z%%M% %I% %E% SMI" 233