1/* 2 * Copyright (C) 1996-2001 Internet Software Consortium. 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM 9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL 10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL 11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING 13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18#if defined(LIBC_SCCS) && !defined(lint) 19static char rcsid[] = 20 "$Id: inet_ntop.c,v 1.13 2001/11/27 01:56:00 gson Exp $"; 21#endif /* LIBC_SCCS and not lint */ 22 23#include <config.h> 24 25#include <errno.h> 26#include <stdio.h> 27#include <string.h> 28 29#include <isc/net.h> 30 31#include "ntp_sprintf.h" 32 33#define NS_INT16SZ 2 34#define NS_IN6ADDRSZ 16 35 36/* 37 * WARNING: Don't even consider trying to compile this on a system where 38 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 39 */ 40 41static const char *inet_ntop4(const unsigned char *src, char *dst, 42 size_t size); 43 44#ifdef AF_INET6 45static const char *inet_ntop6(const unsigned char *src, char *dst, 46 size_t size); 47#endif 48 49/* char * 50 * isc_net_ntop(af, src, dst, size) 51 * convert a network format address to presentation format. 52 * return: 53 * pointer to presentation format address (`dst'), or NULL (see errno). 54 * author: 55 * Paul Vixie, 1996. 56 */ 57const char * 58isc_net_ntop(int af, const void *src, char *dst, size_t size) 59{ 60 switch (af) { 61 case AF_INET: 62 return (inet_ntop4(src, dst, size)); 63#ifdef AF_INET6 64 case AF_INET6: 65 return (inet_ntop6(src, dst, size)); 66#endif 67 default: 68 errno = EAFNOSUPPORT; 69 return (NULL); 70 } 71 /* NOTREACHED */ 72} 73 74/* const char * 75 * inet_ntop4(src, dst, size) 76 * format an IPv4 address 77 * return: 78 * `dst' (as a const) 79 * notes: 80 * (1) uses no statics 81 * (2) takes a unsigned char* not an in_addr as input 82 * author: 83 * Paul Vixie, 1996. 84 */ 85static const char * 86inet_ntop4(const unsigned char *src, char *dst, size_t size) 87{ 88 static const char *fmt = "%u.%u.%u.%u"; 89 char tmp[sizeof("255.255.255.255")]; 90 91 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) >= size) 92 { 93 errno = ENOSPC; 94 return (NULL); 95 } 96 strcpy(dst, tmp); 97 98 return (dst); 99} 100 101/* const char * 102 * isc_inet_ntop6(src, dst, size) 103 * convert IPv6 binary address into presentation (printable) format 104 * author: 105 * Paul Vixie, 1996. 106 */ 107#ifdef AF_INET6 108static const char * 109inet_ntop6(const unsigned char *src, char *dst, size_t size) 110{ 111 /* 112 * Note that int32_t and int16_t need only be "at least" large enough 113 * to contain a value of the specified size. On some systems, like 114 * Crays, there is no such thing as an integer variable with 16 bits. 115 * Keep this in mind if you think this function should have been coded 116 * to use pointer overlays. All the world's not a VAX. 117 */ 118 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 119 struct { int base, len; } best, cur; 120 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 121 int i; 122 123 /* 124 * Preprocess: 125 * Copy the input (bytewise) array into a wordwise array. 126 * Find the longest run of 0x00's in src[] for :: shorthanding. 127 */ 128 memset(words, '\0', sizeof(words)); 129 for (i = 0; i < NS_IN6ADDRSZ; i++) 130 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 131 best.base = -1; 132 best.len = 0; 133 cur.base = -1; 134 cur.len = 0; 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 && 173 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 174 if (!inet_ntop4(src+12, tp, 175 sizeof(tmp) - (tp - tmp))) 176 return (NULL); 177 tp += strlen(tp); 178 break; 179 } 180 tp += SPRINTF((tp, "%x", words[i])); 181 } 182 /* Was it a trailing run of 0x00's? */ 183 if (best.base != -1 && (best.base + best.len) == 184 (NS_IN6ADDRSZ / NS_INT16SZ)) 185 *tp++ = ':'; 186 *tp++ = '\0'; 187 188 /* 189 * Check for overflow, copy, and we're done. 190 */ 191 if ((size_t)(tp - tmp) > size) { 192 errno = ENOSPC; 193 return (NULL); 194 } 195 strcpy(dst, tmp); 196 return (dst); 197} 198#endif /* AF_INET6 */ 199