1 /* $NetBSD: inet_ntop.c,v 1.4 2014/12/10 04:37:59 christos Exp $ */ 2 3 /* 4 * Copyright (C) 2004, 2005, 2007, 2009 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 1.21 2009/07/17 23:47:41 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 #define NS_INT16SZ 2 37 #define NS_IN6ADDRSZ 16 38 39 /* 40 * WARNING: Don't even consider trying to compile this on a system where 41 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 42 */ 43 44 static const char *inet_ntop4(const unsigned char *src, char *dst, 45 size_t size); 46 47 #ifdef AF_INET6 48 static const char *inet_ntop6(const unsigned char *src, char *dst, 49 size_t size); 50 #endif 51 52 /*! char * 53 * isc_net_ntop(af, src, dst, size) 54 * convert a network format address to presentation format. 55 * \return 56 * pointer to presentation format address (`dst'), or NULL (see errno). 57 * \author 58 * Paul Vixie, 1996. 59 */ 60 const char * 61 isc_net_ntop(int af, const void *src, char *dst, size_t size) 62 { 63 switch (af) { 64 case AF_INET: 65 return (inet_ntop4(src, dst, size)); 66 #ifdef AF_INET6 67 case AF_INET6: 68 return (inet_ntop6(src, dst, size)); 69 #endif 70 default: 71 errno = EAFNOSUPPORT; 72 return (NULL); 73 } 74 /* NOTREACHED */ 75 } 76 77 /*! const char * 78 * inet_ntop4(src, dst, size) 79 * format an IPv4 address 80 * \return 81 * `dst' (as a const) 82 * \note 83 * (1) uses no statics 84 * \note 85 * (2) takes a unsigned char* not an in_addr as input 86 * \author 87 * Paul Vixie, 1996. 88 */ 89 static const char * 90 inet_ntop4(const unsigned char *src, char *dst, size_t size) 91 { 92 static const char *fmt = "%u.%u.%u.%u"; 93 char tmp[sizeof("255.255.255.255")]; 94 95 if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size) 96 { 97 errno = ENOSPC; 98 return (NULL); 99 } 100 strcpy(dst, tmp); 101 102 return (dst); 103 } 104 105 /*! const char * 106 * isc_inet_ntop6(src, dst, size) 107 * convert IPv6 binary address into presentation (printable) format 108 * \author 109 * Paul Vixie, 1996. 110 */ 111 #ifdef AF_INET6 112 static const char * 113 inet_ntop6(const unsigned char *src, char *dst, size_t size) 114 { 115 /* 116 * Note that int32_t and int16_t need only be "at least" large enough 117 * to contain a value of the specified size. On some systems, like 118 * Crays, there is no such thing as an integer variable with 16 bits. 119 * Keep this in mind if you think this function should have been coded 120 * to use pointer overlays. All the world's not a VAX. 121 */ 122 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 123 struct { int base, len; } best, cur; 124 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 125 int i; 126 127 /* 128 * Preprocess: 129 * Copy the input (bytewise) array into a wordwise array. 130 * Find the longest run of 0x00's in src[] for :: shorthanding. 131 */ 132 memset(words, '\0', sizeof(words)); 133 for (i = 0; i < NS_IN6ADDRSZ; i++) 134 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 135 best.base = -1; 136 cur.base = -1; 137 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 138 if (words[i] == 0) { 139 if (cur.base == -1) 140 cur.base = i, cur.len = 1; 141 else 142 cur.len++; 143 } else { 144 if (cur.base != -1) { 145 if (best.base == -1 || cur.len > best.len) 146 best = cur; 147 cur.base = -1; 148 } 149 } 150 } 151 if (cur.base != -1) { 152 if (best.base == -1 || cur.len > best.len) 153 best = cur; 154 } 155 if (best.base != -1 && best.len < 2) 156 best.base = -1; 157 158 /* 159 * Format the result. 160 */ 161 tp = tmp; 162 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 163 /* Are we inside the best run of 0x00's? */ 164 if (best.base != -1 && i >= best.base && 165 i < (best.base + best.len)) { 166 if (i == best.base) 167 *tp++ = ':'; 168 continue; 169 } 170 /* Are we following an initial run of 0x00s or any real hex? */ 171 if (i != 0) 172 *tp++ = ':'; 173 /* Is this address an encapsulated IPv4? */ 174 if (i == 6 && best.base == 0 && (best.len == 6 || 175 (best.len == 7 && words[7] != 0x0001) || 176 (best.len == 5 && words[5] == 0xffff))) { 177 if (!inet_ntop4(src+12, tp, 178 sizeof(tmp) - (tp - tmp))) 179 return (NULL); 180 tp += strlen(tp); 181 break; 182 } 183 tp += sprintf(tp, "%x", words[i]); 184 } 185 /* Was it a trailing run of 0x00's? */ 186 if (best.base != -1 && (best.base + best.len) == 187 (NS_IN6ADDRSZ / NS_INT16SZ)) 188 *tp++ = ':'; 189 *tp++ = '\0'; 190 191 /* 192 * Check for overflow, copy, and we're done. 193 */ 194 if ((size_t)(tp - tmp) > size) { 195 errno = ENOSPC; 196 return (NULL); 197 } 198 strcpy(dst, tmp); 199 return (dst); 200 } 201 #endif /* AF_INET6 */ 202