1 /* $NetBSD: inet_ntop.c,v 1.1.1.1 2009/04/12 15:33:35 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (c) 1996-1999 by Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and 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 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #if defined(LIBC_SCCS) && !defined(lint) 21 static const char rcsid[] = "Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp"; 22 #endif /* LIBC_SCCS and not lint */ 23 24 #include "port_before.h" 25 26 #include <sys/param.h> 27 #include <sys/types.h> 28 #include <sys/socket.h> 29 30 #include <netinet/in.h> 31 #include <arpa/inet.h> 32 #include <arpa/nameser.h> 33 34 #include <errno.h> 35 #include <stdio.h> 36 #include <string.h> 37 38 #include "port_after.h" 39 40 #ifdef SPRINTF_CHAR 41 # define SPRINTF(x) strlen(sprintf/**/x) 42 #else 43 # define SPRINTF(x) ((size_t)sprintf x) 44 #endif 45 46 /*% 47 * WARNING: Don't even consider trying to compile this on a system where 48 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 49 */ 50 51 static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); 52 static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size)); 53 54 /* char * 55 * inet_ntop(af, src, dst, size) 56 * convert a network format address to presentation format. 57 * return: 58 * pointer to presentation format address (`dst'), or NULL (see errno). 59 * author: 60 * Paul Vixie, 1996. 61 */ 62 const char * 63 inet_ntop(af, src, dst, size) 64 int af; 65 const void *src; 66 char *dst; 67 size_t size; 68 { 69 switch (af) { 70 case AF_INET: 71 return (inet_ntop4(src, dst, size)); 72 case AF_INET6: 73 return (inet_ntop6(src, dst, size)); 74 default: 75 errno = EAFNOSUPPORT; 76 return (NULL); 77 } 78 /* NOTREACHED */ 79 } 80 81 /* const char * 82 * inet_ntop4(src, dst, size) 83 * format an IPv4 address 84 * return: 85 * `dst' (as a const) 86 * notes: 87 * (1) uses no statics 88 * (2) takes a u_char* not an in_addr as input 89 * author: 90 * Paul Vixie, 1996. 91 */ 92 static const char * 93 inet_ntop4(src, dst, size) 94 const u_char *src; 95 char *dst; 96 size_t size; 97 { 98 static const char fmt[] = "%u.%u.%u.%u"; 99 char tmp[sizeof "255.255.255.255"]; 100 101 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) >= size) { 102 errno = ENOSPC; 103 return (NULL); 104 } 105 strcpy(dst, tmp); 106 return (dst); 107 } 108 109 /* const char * 110 * inet_ntop6(src, dst, size) 111 * convert IPv6 binary address into presentation (printable) format 112 * author: 113 * Paul Vixie, 1996. 114 */ 115 static const char * 116 inet_ntop6(src, dst, size) 117 const u_char *src; 118 char *dst; 119 size_t size; 120 { 121 /* 122 * Note that int32_t and int16_t need only be "at least" large enough 123 * to contain a value of the specified size. On some systems, like 124 * Crays, there is no such thing as an integer variable with 16 bits. 125 * Keep this in mind if you think this function should have been coded 126 * to use pointer overlays. All the world's not a VAX. 127 */ 128 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 129 struct { int base, len; } best, cur; 130 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 131 int i; 132 133 /* 134 * Preprocess: 135 * Copy the input (bytewise) array into a wordwise array. 136 * Find the longest run of 0x00's in src[] for :: shorthanding. 137 */ 138 memset(words, '\0', sizeof words); 139 for (i = 0; i < NS_IN6ADDRSZ; i++) 140 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 141 best.base = -1; 142 best.len = 0; 143 cur.base = -1; 144 cur.len = 0; 145 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 146 if (words[i] == 0) { 147 if (cur.base == -1) 148 cur.base = i, cur.len = 1; 149 else 150 cur.len++; 151 } else { 152 if (cur.base != -1) { 153 if (best.base == -1 || cur.len > best.len) 154 best = cur; 155 cur.base = -1; 156 } 157 } 158 } 159 if (cur.base != -1) { 160 if (best.base == -1 || cur.len > best.len) 161 best = cur; 162 } 163 if (best.base != -1 && best.len < 2) 164 best.base = -1; 165 166 /* 167 * Format the result. 168 */ 169 tp = tmp; 170 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 171 /* Are we inside the best run of 0x00's? */ 172 if (best.base != -1 && i >= best.base && 173 i < (best.base + best.len)) { 174 if (i == best.base) 175 *tp++ = ':'; 176 continue; 177 } 178 /* Are we following an initial run of 0x00s or any real hex? */ 179 if (i != 0) 180 *tp++ = ':'; 181 /* Is this address an encapsulated IPv4? */ 182 if (i == 6 && best.base == 0 && (best.len == 6 || 183 (best.len == 7 && words[7] != 0x0001) || 184 (best.len == 5 && words[5] == 0xffff))) { 185 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 186 return (NULL); 187 tp += strlen(tp); 188 break; 189 } 190 tp += SPRINTF((tp, "%x", words[i])); 191 } 192 /* Was it a trailing run of 0x00's? */ 193 if (best.base != -1 && (best.base + best.len) == 194 (NS_IN6ADDRSZ / NS_INT16SZ)) 195 *tp++ = ':'; 196 *tp++ = '\0'; 197 198 /* 199 * Check for overflow, copy, and we're done. 200 */ 201 if ((size_t)(tp - tmp) > size) { 202 errno = ENOSPC; 203 return (NULL); 204 } 205 strcpy(dst, tmp); 206 return (dst); 207 } 208 209 /*! \file */ 210