1 /* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */ 2 3 /* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */ 4 5 /* Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS 12 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 13 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 14 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 15 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 16 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 17 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 18 * SOFTWARE. 19 */ 20 21 #include "includes.h" 22 23 #ifndef HAVE_INET_NTOP 24 25 #if defined(LIBC_SCCS) && !defined(lint) 26 #if 0 27 static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $"; 28 #else 29 static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $"; 30 #endif 31 #endif /* LIBC_SCCS and not lint */ 32 33 #include <sys/param.h> 34 #include <sys/types.h> 35 #include <sys/socket.h> 36 #include <netinet/in.h> 37 #include <arpa/inet.h> 38 #ifndef HAVE_CYGWIN 39 #include <arpa/nameser.h> 40 #endif 41 #include <string.h> 42 #include <errno.h> 43 #include <stdio.h> 44 45 #ifndef IN6ADDRSZ 46 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 47 #endif 48 49 #ifndef INT16SZ 50 #define INT16SZ 2 /* for systems without 16-bit ints */ 51 #endif 52 53 /* 54 * WARNING: Don't even consider trying to compile this on a system where 55 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 56 */ 57 58 static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 59 static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 60 61 /* char * 62 * inet_ntop(af, src, dst, size) 63 * convert a network format address to presentation format. 64 * return: 65 * pointer to presentation format address (`dst'), or NULL (see errno). 66 * author: 67 * Paul Vixie, 1996. 68 */ 69 const char * 70 inet_ntop(af, src, dst, size) 71 int af; 72 const void *src; 73 char *dst; 74 size_t size; 75 { 76 switch (af) { 77 case AF_INET: 78 return (inet_ntop4(src, dst, size)); 79 case AF_INET6: 80 return (inet_ntop6(src, dst, size)); 81 default: 82 errno = EAFNOSUPPORT; 83 return (NULL); 84 } 85 /* NOTREACHED */ 86 } 87 88 /* const char * 89 * inet_ntop4(src, dst, size) 90 * format an IPv4 address, more or less like inet_ntoa() 91 * return: 92 * `dst' (as a const) 93 * notes: 94 * (1) uses no statics 95 * (2) takes a u_char* not an in_addr as input 96 * author: 97 * Paul Vixie, 1996. 98 */ 99 static const char * 100 inet_ntop4(src, dst, size) 101 const u_char *src; 102 char *dst; 103 size_t size; 104 { 105 static const char fmt[] = "%u.%u.%u.%u"; 106 char tmp[sizeof "255.255.255.255"]; 107 int l; 108 109 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]); 110 if (l <= 0 || l >= size) { 111 errno = ENOSPC; 112 return (NULL); 113 } 114 strlcpy(dst, tmp, size); 115 return (dst); 116 } 117 118 /* const char * 119 * inet_ntop6(src, dst, size) 120 * convert IPv6 binary address into presentation (printable) format 121 * author: 122 * Paul Vixie, 1996. 123 */ 124 static const char * 125 inet_ntop6(src, dst, size) 126 const u_char *src; 127 char *dst; 128 size_t size; 129 { 130 /* 131 * Note that int32_t and int16_t need only be "at least" large enough 132 * to contain a value of the specified size. On some systems, like 133 * Crays, there is no such thing as an integer variable with 16 bits. 134 * Keep this in mind if you think this function should have been coded 135 * to use pointer overlays. All the world's not a VAX. 136 */ 137 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"]; 138 char *tp, *ep; 139 struct { int base, len; } best, cur; 140 u_int words[IN6ADDRSZ / INT16SZ]; 141 int i; 142 int advance; 143 144 /* 145 * Preprocess: 146 * Copy the input (bytewise) array into a wordwise array. 147 * Find the longest run of 0x00's in src[] for :: shorthanding. 148 */ 149 memset(words, '\0', sizeof words); 150 for (i = 0; i < IN6ADDRSZ; i++) 151 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 152 best.base = -1; 153 cur.base = -1; 154 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 155 if (words[i] == 0) { 156 if (cur.base == -1) 157 cur.base = i, cur.len = 1; 158 else 159 cur.len++; 160 } else { 161 if (cur.base != -1) { 162 if (best.base == -1 || cur.len > best.len) 163 best = cur; 164 cur.base = -1; 165 } 166 } 167 } 168 if (cur.base != -1) { 169 if (best.base == -1 || cur.len > best.len) 170 best = cur; 171 } 172 if (best.base != -1 && best.len < 2) 173 best.base = -1; 174 175 /* 176 * Format the result. 177 */ 178 tp = tmp; 179 ep = tmp + sizeof(tmp); 180 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) { 181 /* Are we inside the best run of 0x00's? */ 182 if (best.base != -1 && i >= best.base && 183 i < (best.base + best.len)) { 184 if (i == best.base) { 185 if (tp + 1 >= ep) 186 return (NULL); 187 *tp++ = ':'; 188 } 189 continue; 190 } 191 /* Are we following an initial run of 0x00s or any real hex? */ 192 if (i != 0) { 193 if (tp + 1 >= ep) 194 return (NULL); 195 *tp++ = ':'; 196 } 197 /* Is this address an encapsulated IPv4? */ 198 if (i == 6 && best.base == 0 && 199 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 200 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp))) 201 return (NULL); 202 tp += strlen(tp); 203 break; 204 } 205 advance = snprintf(tp, ep - tp, "%x", words[i]); 206 if (advance <= 0 || advance >= ep - tp) 207 return (NULL); 208 tp += advance; 209 } 210 /* Was it a trailing run of 0x00's? */ 211 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) { 212 if (tp + 1 >= ep) 213 return (NULL); 214 *tp++ = ':'; 215 } 216 if (tp + 1 >= ep) 217 return (NULL); 218 *tp++ = '\0'; 219 220 /* 221 * Check for overflow, copy, and we're done. 222 */ 223 if ((size_t)(tp - tmp) > size) { 224 errno = ENOSPC; 225 return (NULL); 226 } 227 strlcpy(dst, tmp, size); 228 return (dst); 229 } 230 231 #endif /* !HAVE_INET_NTOP */ 232