1/* 2 * Copyright (C) 2004, 2005, 2007, 2009 Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (C) 1996-2001 Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15 * PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18/*! \file */ 19 20#if defined(LIBC_SCCS) && !defined(lint) 21static char rcsid[] = 22 "$Id: inet_ntop.c,v 1.21 2009/07/17 23:47:41 tbox Exp $"; 23#endif /* LIBC_SCCS and not lint */ 24 25#include <config.h> 26 27#include <errno.h> 28#include <stdio.h> 29#include <string.h> 30 31#include <isc/net.h> 32#include <isc/print.h> 33 34#define NS_INT16SZ 2 35#define NS_IN6ADDRSZ 16 36 37/* 38 * WARNING: Don't even consider trying to compile this on a system where 39 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 40 */ 41 42static const char *inet_ntop4(const unsigned char *src, char *dst, 43 size_t size); 44 45#ifdef AF_INET6 46static const char *inet_ntop6(const unsigned char *src, char *dst, 47 size_t size); 48#endif 49 50/*! char * 51 * isc_net_ntop(af, src, dst, size) 52 * convert a network format address to presentation format. 53 * \return 54 * pointer to presentation format address (`dst'), or NULL (see errno). 55 * \author 56 * Paul Vixie, 1996. 57 */ 58const char * 59isc_net_ntop(int af, const void *src, char *dst, size_t size) 60{ 61 switch (af) { 62 case AF_INET: 63 return (inet_ntop4(src, dst, size)); 64#ifdef AF_INET6 65 case AF_INET6: 66 return (inet_ntop6(src, dst, size)); 67#endif 68 default: 69 errno = EAFNOSUPPORT; 70 return (NULL); 71 } 72 /* NOTREACHED */ 73} 74 75/*! const char * 76 * inet_ntop4(src, dst, size) 77 * format an IPv4 address 78 * \return 79 * `dst' (as a const) 80 * \note 81 * (1) uses no statics 82 * \note 83 * (2) takes a unsigned char* not an in_addr as input 84 * \author 85 * Paul Vixie, 1996. 86 */ 87static const char * 88inet_ntop4(const unsigned char *src, char *dst, size_t size) 89{ 90 static const char *fmt = "%u.%u.%u.%u"; 91 char tmp[sizeof("255.255.255.255")]; 92 93 if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size) 94 { 95 errno = ENOSPC; 96 return (NULL); 97 } 98 strcpy(dst, tmp); 99 100 return (dst); 101} 102 103/*! const char * 104 * isc_inet_ntop6(src, dst, size) 105 * convert IPv6 binary address into presentation (printable) format 106 * \author 107 * Paul Vixie, 1996. 108 */ 109#ifdef AF_INET6 110static const char * 111inet_ntop6(const unsigned char *src, char *dst, size_t size) 112{ 113 /* 114 * Note that int32_t and int16_t need only be "at least" large enough 115 * to contain a value of the specified size. On some systems, like 116 * Crays, there is no such thing as an integer variable with 16 bits. 117 * Keep this in mind if you think this function should have been coded 118 * to use pointer overlays. All the world's not a VAX. 119 */ 120 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 121 struct { int base, len; } best, cur; 122 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 123 int i; 124 125 /* 126 * Preprocess: 127 * Copy the input (bytewise) array into a wordwise array. 128 * Find the longest run of 0x00's in src[] for :: shorthanding. 129 */ 130 memset(words, '\0', sizeof(words)); 131 for (i = 0; i < NS_IN6ADDRSZ; i++) 132 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 133 best.base = -1; 134 cur.base = -1; 135 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 136 if (words[i] == 0) { 137 if (cur.base == -1) 138 cur.base = i, cur.len = 1; 139 else 140 cur.len++; 141 } else { 142 if (cur.base != -1) { 143 if (best.base == -1 || cur.len > best.len) 144 best = cur; 145 cur.base = -1; 146 } 147 } 148 } 149 if (cur.base != -1) { 150 if (best.base == -1 || cur.len > best.len) 151 best = cur; 152 } 153 if (best.base != -1 && best.len < 2) 154 best.base = -1; 155 156 /* 157 * Format the result. 158 */ 159 tp = tmp; 160 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 161 /* Are we inside the best run of 0x00's? */ 162 if (best.base != -1 && i >= best.base && 163 i < (best.base + best.len)) { 164 if (i == best.base) 165 *tp++ = ':'; 166 continue; 167 } 168 /* Are we following an initial run of 0x00s or any real hex? */ 169 if (i != 0) 170 *tp++ = ':'; 171 /* Is this address an encapsulated IPv4? */ 172 if (i == 6 && best.base == 0 && (best.len == 6 || 173 (best.len == 7 && words[7] != 0x0001) || 174 (best.len == 5 && words[5] == 0xffff))) { 175 if (!inet_ntop4(src+12, tp, 176 sizeof(tmp) - (tp - tmp))) 177 return (NULL); 178 tp += strlen(tp); 179 break; 180 } 181 tp += sprintf(tp, "%x", words[i]); 182 } 183 /* Was it a trailing run of 0x00's? */ 184 if (best.base != -1 && (best.base + best.len) == 185 (NS_IN6ADDRSZ / NS_INT16SZ)) 186 *tp++ = ':'; 187 *tp++ = '\0'; 188 189 /* 190 * Check for overflow, copy, and we're done. 191 */ 192 if ((size_t)(tp - tmp) > size) { 193 errno = ENOSPC; 194 return (NULL); 195 } 196 strcpy(dst, tmp); 197 return (dst); 198} 199#endif /* AF_INET6 */ 200