1/* 2 * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (C) 1996-2001, 2003 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 lwinetntop.c 19 */ 20#if defined(LIBC_SCCS) && !defined(lint) 21static char rcsid[] = 22 "$Id: lwinetntop.c,v 1.18 2007/06/19 23:47:22 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 <lwres/net.h> 32#include "print_p.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 * lwres_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 * 59lwres_net_ntop(int af, const void *src, char *dst, size_t size) { 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 static const char fmt[] = "%u.%u.%u.%u"; 88 char tmp[sizeof("255.255.255.255")]; 89 size_t len; 90 91 len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 92 if (len >= size) { 93 errno = ENOSPC; 94 return (NULL); 95 } 96 strcpy(dst, tmp); 97 98 return (dst); 99} 100 101/*! const char * 102 * 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 * Note that int32_t and int16_t need only be "at least" large enough 112 * to contain a value of the specified size. On some systems, like 113 * Crays, there is no such thing as an integer variable with 16 bits. 114 * Keep this in mind if you think this function should have been coded 115 * to use pointer overlays. All the world's not a VAX. 116 */ 117 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp; 118 struct { int base, len; } best, cur; 119 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; 120 int i; 121 122 /* 123 * Preprocess: 124 * Copy the input (bytewise) array into a wordwise array. 125 * Find the longest run of 0x00's in src[] for :: shorthanding. 126 */ 127 memset(words, '\0', sizeof(words)); 128 for (i = 0; i < NS_IN6ADDRSZ; i++) 129 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 130 best.base = -1; 131 best.len = 0; 132 cur.base = -1; 133 cur.len = 0; 134 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 135 if (words[i] == 0) { 136 if (cur.base == -1) 137 cur.base = i, cur.len = 1; 138 else 139 cur.len++; 140 } else { 141 if (cur.base != -1) { 142 if (best.base == -1 || cur.len > best.len) 143 best = cur; 144 cur.base = -1; 145 } 146 } 147 } 148 if (cur.base != -1) { 149 if (best.base == -1 || cur.len > best.len) 150 best = cur; 151 } 152 if (best.base != -1 && best.len < 2) 153 best.base = -1; 154 155 /* 156 * Format the result. 157 */ 158 tp = tmp; 159 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 160 /* Are we inside the best run of 0x00's? */ 161 if (best.base != -1 && i >= best.base && 162 i < (best.base + best.len)) { 163 if (i == best.base) 164 *tp++ = ':'; 165 continue; 166 } 167 /* Are we following an initial run of 0x00s or any real hex? */ 168 if (i != 0) 169 *tp++ = ':'; 170 /* Is this address an encapsulated IPv4? */ 171 if (i == 6 && best.base == 0 && 172 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 173 if (!inet_ntop4(src+12, tp, 174 sizeof(tmp) - (tp - tmp))) 175 return (NULL); 176 tp += strlen(tp); 177 break; 178 } 179 tp += sprintf(tp, "%x", words[i]); /* XXX */ 180 } 181 /* Was it a trailing run of 0x00's? */ 182 if (best.base != -1 && (best.base + best.len) == 183 (NS_IN6ADDRSZ / NS_INT16SZ)) 184 *tp++ = ':'; 185 *tp++ = '\0'; 186 187 /* 188 * Check for overflow, copy, and we're done. 189 */ 190 if ((size_t)(tp - tmp) > size) { 191 errno = ENOSPC; 192 return (NULL); 193 } 194 strcpy(dst, tmp); 195 return (dst); 196} 197#endif /* AF_INET6 */ 198