1 /* $NetBSD: inet_ntop.c,v 1.2 2010/12/04 23:08:33 christos Exp $ */ 2 3 /* 4 * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (C) 1996-2001 Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and/or distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 13 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 17 * PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 /*! \file */ 21 22 #if defined(LIBC_SCCS) && !defined(lint) 23 static char rcsid[] = 24 "Id: inet_ntop.c,v 1.19 2007/06/19 23:47:17 tbox Exp"; 25 #endif /* LIBC_SCCS and not lint */ 26 27 #include <config.h> 28 29 #include <errno.h> 30 #include <stdio.h> 31 #include <string.h> 32 33 #include <isc/net.h> 34 #include <isc/print.h> 35 36 #include "ntp_sprintf.h" /* NTP local change, helps SunOS 4 */ 37 38 #define NS_INT16SZ 2 39 #define NS_IN6ADDRSZ 16 40 41 /* 42 * WARNING: Don't even consider trying to compile this on a system where 43 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 44 */ 45 46 #ifdef notdef 47 static const char *inet_ntop4(const unsigned char *src, char *dst, 48 size_t size); 49 50 #ifdef AF_INET6 51 static const char *inet_ntop6(const unsigned char *src, char *dst, 52 size_t size); 53 #endif 54 #endif 55 56 #ifdef notdef 57 /*! char * 58 * isc_net_ntop(af, src, dst, size) 59 * convert a network format address to presentation format. 60 * \return 61 * pointer to presentation format address (`dst'), or NULL (see errno). 62 * \author 63 * Paul Vixie, 1996. 64 */ 65 const char * 66 isc_net_ntop(int af, const void *src, char *dst, size_t size) 67 { 68 switch (af) { 69 case AF_INET: 70 return (inet_ntop4(src, dst, size)); 71 #ifdef AF_INET6 72 case AF_INET6: 73 return (inet_ntop6(src, dst, size)); 74 #endif 75 default: 76 errno = EAFNOSUPPORT; 77 return (NULL); 78 } 79 /* NOTREACHED */ 80 } 81 82 /*! const char * 83 * inet_ntop4(src, dst, size) 84 * format an IPv4 address 85 * \return 86 * `dst' (as a const) 87 * \note 88 * (1) uses no statics 89 * \note 90 * (2) takes a unsigned char* not an in_addr as input 91 * \author 92 * Paul Vixie, 1996. 93 */ 94 static const char * 95 inet_ntop4(const unsigned char *src, char *dst, size_t size) 96 { 97 static const char *fmt = "%u.%u.%u.%u"; 98 char tmp[sizeof("255.255.255.255")]; 99 100 /* NTP local change to use SNPRINTF() macro for SunOS4 compat */ 101 if (SNPRINTF((tmp, sizeof(tmp), fmt, src[0], src[1], src[2], 102 src[3])) >= size) 103 { 104 errno = ENOSPC; 105 return (NULL); 106 } 107 strcpy(dst, tmp); 108 109 return (dst); 110 } 111 112 /*! const char * 113 * isc_inet_ntop6(src, dst, size) 114 * convert IPv6 binary address into presentation (printable) format 115 * \author 116 * Paul Vixie, 1996. 117 */ 118 #ifdef AF_INET6 119 static const char * 120 inet_ntop6(const unsigned char *src, char *dst, size_t size) 121 { 122 /* 123 * Note that int32_t and int16_t need only be "at least" large enough 124 * to contain a value of the specified size. On some systems, like 125 * Crays, there is no such thing as an integer variable with 16 bits. 126 * Keep this in mind if you think this function should have been coded 127 * to use pointer overlays. All the world's not a VAX. 128 */ 129 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 130 struct { int base, len; } best, cur; 131 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 132 int i; 133 134 /* 135 * Preprocess: 136 * Copy the input (bytewise) array into a wordwise array. 137 * Find the longest run of 0x00's in src[] for :: shorthanding. 138 */ 139 memset(words, '\0', sizeof(words)); 140 for (i = 0; i < NS_IN6ADDRSZ; i++) 141 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 142 best.base = -1; 143 cur.base = -1; 144 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 145 if (words[i] == 0) { 146 if (cur.base == -1) 147 cur.base = i, cur.len = 1; 148 else 149 cur.len++; 150 } else { 151 if (cur.base != -1) { 152 if (best.base == -1 || cur.len > best.len) 153 best = cur; 154 cur.base = -1; 155 } 156 } 157 } 158 if (cur.base != -1) { 159 if (best.base == -1 || cur.len > best.len) 160 best = cur; 161 } 162 if (best.base != -1 && best.len < 2) 163 best.base = -1; 164 165 /* 166 * Format the result. 167 */ 168 tp = tmp; 169 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 170 /* Are we inside the best run of 0x00's? */ 171 if (best.base != -1 && i >= best.base && 172 i < (best.base + best.len)) { 173 if (i == best.base) 174 *tp++ = ':'; 175 continue; 176 } 177 /* Are we following an initial run of 0x00s or any real hex? */ 178 if (i != 0) 179 *tp++ = ':'; 180 /* Is this address an encapsulated IPv4? */ 181 if (i == 6 && best.base == 0 && 182 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 183 if (!inet_ntop4(src+12, tp, 184 sizeof(tmp) - (tp - tmp))) 185 return (NULL); 186 tp += strlen(tp); 187 break; 188 } 189 tp += SPRINTF((tp, "%x", words[i])); /* NTP local change */ 190 } 191 /* Was it a trailing run of 0x00's? */ 192 if (best.base != -1 && (best.base + best.len) == 193 (NS_IN6ADDRSZ / NS_INT16SZ)) 194 *tp++ = ':'; 195 *tp++ = '\0'; 196 197 /* 198 * Check for overflow, copy, and we're done. 199 */ 200 if ((size_t)(tp - tmp) > size) { 201 errno = ENOSPC; 202 return (NULL); 203 } 204 strcpy(dst, tmp); 205 return (dst); 206 } 207 #endif /* AF_INET6 */ 208 #endif 209