1 /* 2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (c) 1996-1999 by Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and 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 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static const char rcsid[] = "$Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp $"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include "port_before.h" 23 24 #include <sys/param.h> 25 #include <sys/types.h> 26 #include <sys/socket.h> 27 28 #include <netinet/in.h> 29 #include "arpa/inet.h" 30 #include <arpa/nameser.h> 31 32 #include <errno.h> 33 #include <stdio.h> 34 #include <string.h> 35 36 #include "port_after.h" 37 38 #ifdef SPRINTF_CHAR 39 # define SPRINTF(x) strlen(sprintf/**/x) 40 #else 41 # define SPRINTF(x) ((size_t)sprintf x) 42 #endif 43 44 /*% 45 * WARNING: Don't even consider trying to compile this on a system where 46 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 47 */ 48 49 static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); 50 static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size)); 51 52 /* char * 53 * inet_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 inet_ntop(int af, const void *src, char *dst, socklen_t size) 62 { 63 switch (af) { 64 case AF_INET: 65 return (inet_ntop4(src, dst, size)); 66 case AF_INET6: 67 return (inet_ntop6(src, dst, size)); 68 default: 69 errno = EAFNOSUPPORT; 70 return (NULL); 71 } 72 /* NOTREACHED */ 73 } 74 75 /* const char * 76 * inet_ntop4(src, dst, size) 77 * format an IPv4 address 78 * return: 79 * `dst' (as a const) 80 * notes: 81 * (1) uses no statics 82 * (2) takes a u_char* not an in_addr as input 83 * author: 84 * Paul Vixie, 1996. 85 */ 86 static const char * 87 inet_ntop4(const u_char *src, char *dst, size_t size) 88 { 89 static const char fmt[] = "%u.%u.%u.%u"; 90 char tmp[sizeof "255.255.255.255"]; 91 92 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) >= size) { 93 errno = ENOSPC; 94 return (NULL); 95 } 96 strcpy(dst, tmp); 97 return (dst); 98 } 99 100 /* const char * 101 * inet_ntop6(src, dst, size) 102 * convert IPv6 binary address into presentation (printable) format 103 * author: 104 * Paul Vixie, 1996. 105 */ 106 static const char * 107 inet_ntop6(const u_char *src, char *dst, size_t size) 108 { 109 /* 110 * Note that int32_t and int16_t need only be "at least" large enough 111 * to contain a value of the specified size. On some systems, like 112 * Crays, there is no such thing as an integer variable with 16 bits. 113 * Keep this in mind if you think this function should have been coded 114 * to use pointer overlays. All the world's not a VAX. 115 */ 116 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 117 struct { int base, len; } best, cur; 118 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 119 int i; 120 121 /* 122 * Preprocess: 123 * Copy the input (bytewise) array into a wordwise array. 124 * Find the longest run of 0x00's in src[] for :: shorthanding. 125 */ 126 memset(words, '\0', sizeof words); 127 for (i = 0; i < NS_IN6ADDRSZ; i++) 128 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 129 best.base = -1; 130 best.len = 0; 131 cur.base = -1; 132 cur.len = 0; 133 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 134 if (words[i] == 0) { 135 if (cur.base == -1) 136 cur.base = i, cur.len = 1; 137 else 138 cur.len++; 139 } else { 140 if (cur.base != -1) { 141 if (best.base == -1 || cur.len > best.len) 142 best = cur; 143 cur.base = -1; 144 } 145 } 146 } 147 if (cur.base != -1) { 148 if (best.base == -1 || cur.len > best.len) 149 best = cur; 150 } 151 if (best.base != -1 && best.len < 2) 152 best.base = -1; 153 154 /* 155 * Format the result. 156 */ 157 tp = tmp; 158 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 159 /* Are we inside the best run of 0x00's? */ 160 if (best.base != -1 && i >= best.base && 161 i < (best.base + best.len)) { 162 if (i == best.base) 163 *tp++ = ':'; 164 continue; 165 } 166 /* Are we following an initial run of 0x00s or any real hex? */ 167 if (i != 0) 168 *tp++ = ':'; 169 /* Is this address an encapsulated IPv4? */ 170 if (i == 6 && best.base == 0 && (best.len == 6 || 171 (best.len == 7 && words[7] != 0x0001) || 172 (best.len == 5 && words[5] == 0xffff))) { 173 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 174 return (NULL); 175 tp += strlen(tp); 176 break; 177 } 178 tp += SPRINTF((tp, "%x", words[i])); 179 } 180 /* Was it a trailing run of 0x00's? */ 181 if (best.base != -1 && (best.base + best.len) == 182 (NS_IN6ADDRSZ / NS_INT16SZ)) 183 *tp++ = ':'; 184 *tp++ = '\0'; 185 186 /* 187 * Check for overflow, copy, and we're done. 188 */ 189 if ((size_t)(tp - tmp) > size) { 190 errno = ENOSPC; 191 return (NULL); 192 } 193 strcpy(dst, tmp); 194 return (dst); 195 } 196 197 #ifdef _LIBC 198 /* 199 * Weak aliases for applications that use certain private entry points, 200 * and fail to include <arpa/inet.h>. 201 */ 202 #undef inet_ntop 203 __weak_reference(__inet_ntop, inet_ntop); 204 #endif 205 /*! \file */ 206