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) 21 static 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 42 static const char *inet_ntop4(const unsigned char *src, char *dst, 43 size_t size); 44 45 #ifdef AF_INET6 46 static const char *inet_ntop6(const unsigned char *src, char *dst, 47 size_t size); 48 #endif 49 const char *isc_net_ntop(int af, const void *src, char *dst, size_t size); 50 51 /*! char * 52 * isc_net_ntop(af, src, dst, size) 53 * convert a network format address to presentation format. 54 * \return 55 * pointer to presentation format address (`dst'), or NULL (see errno). 56 * \author 57 * Paul Vixie, 1996. 58 */ 59 const char * 60 isc_net_ntop(int af, const void *src, char *dst, size_t size) 61 { 62 switch (af) { 63 case AF_INET: 64 return (inet_ntop4(src, dst, size)); 65 #ifdef AF_INET6 66 case AF_INET6: 67 return (inet_ntop6(src, dst, size)); 68 #endif 69 default: 70 errno = EAFNOSUPPORT; 71 return (NULL); 72 } 73 /* NOTREACHED */ 74 } 75 76 /*! const char * 77 * inet_ntop4(src, dst, size) 78 * format an IPv4 address 79 * \return 80 * `dst' (as a const) 81 * \note 82 * (1) uses no statics 83 * \note 84 * (2) takes a unsigned char* not an in_addr as input 85 * \author 86 * Paul Vixie, 1996. 87 */ 88 static const char * 89 inet_ntop4(const unsigned char *src, char *dst, size_t size) 90 { 91 static const char *fmt = "%u.%u.%u.%u"; 92 char tmp[sizeof("255.255.255.255")]; 93 int len; 94 95 len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 96 if (len < 0 || (size_t)len >= size) 97 { 98 errno = ENOSPC; 99 return (NULL); 100 } 101 memcpy(dst, tmp, 1 + len); 102 103 return (dst); 104 } 105 106 /*! const char * 107 * isc_inet_ntop6(src, dst, size) 108 * convert IPv6 binary address into presentation (printable) format 109 * \author 110 * Paul Vixie, 1996. 111 */ 112 #ifdef AF_INET6 113 static const char * 114 inet_ntop6(const unsigned char *src, char *dst, size_t size) 115 { 116 /* 117 * Note that int32_t and int16_t need only be "at least" large enough 118 * to contain a value of the specified size. On some systems, like 119 * Crays, there is no such thing as an integer variable with 16 bits. 120 * Keep this in mind if you think this function should have been coded 121 * to use pointer overlays. All the world's not a VAX. 122 */ 123 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 124 struct { int base, len; } best, cur; 125 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 126 int i; 127 128 /* 129 * Preprocess: 130 * Copy the input (bytewise) array into a wordwise array. 131 * Find the longest run of 0x00's in src[] for :: shorthanding. 132 */ 133 memset(words, '\0', sizeof(words)); 134 for (i = 0; i < NS_IN6ADDRSZ; i++) 135 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 136 best.base = -1; 137 cur.base = -1; 138 best.len = cur.len = 0; 139 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 140 if (words[i] == 0) { 141 if (cur.base == -1) 142 cur.base = i, cur.len = 1; 143 else 144 cur.len++; 145 } else { 146 if (cur.base != -1) { 147 if (best.base == -1 || cur.len > best.len) 148 best = cur; 149 cur.base = -1; 150 } 151 } 152 } 153 if (cur.base != -1) { 154 if (best.base == -1 || cur.len > best.len) 155 best = cur; 156 } 157 if (best.base != -1 && best.len < 2) 158 best.base = -1; 159 160 /* 161 * Format the result. 162 */ 163 tp = tmp; 164 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 165 /* Are we inside the best run of 0x00's? */ 166 if (best.base != -1 && i >= best.base && 167 i < (best.base + best.len)) { 168 if (i == best.base) 169 *tp++ = ':'; 170 continue; 171 } 172 /* Are we following an initial run of 0x00s or any real hex? */ 173 if (i != 0) 174 *tp++ = ':'; 175 /* Is this address an encapsulated IPv4? */ 176 if (i == 6 && best.base == 0 && (best.len == 6 || 177 (best.len == 7 && words[7] != 0x0001) || 178 (best.len == 5 && words[5] == 0xffff))) { 179 if (!inet_ntop4(src+12, tp, 180 sizeof(tmp) - (tp - tmp))) 181 return (NULL); 182 tp += strlen(tp); 183 break; 184 } 185 tp += snprintf(tp, sizeof(tmp) - (tp - tmp), "%x", words[i]); 186 } 187 /* Was it a trailing run of 0x00's? */ 188 if (best.base != -1 && (best.base + best.len) == 189 (NS_IN6ADDRSZ / NS_INT16SZ)) 190 *tp++ = ':'; 191 *tp++ = '\0'; 192 193 /* 194 * Check for overflow, copy, and we're done. 195 */ 196 if ((size_t)(tp - tmp) > size) { 197 errno = ENOSPC; 198 return (NULL); 199 } 200 memcpy(dst, tmp, (size_t)(tp - tmp)); 201 return (dst); 202 } 203 #endif /* AF_INET6 */ 204