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 <sys/param.h> 23 #include <sys/types.h> 24 #include <sys/socket.h> 25 26 #include <netinet/in.h> 27 #include <arpa/inet.h> 28 #include <arpa/nameser.h> 29 30 #include <errno.h> 31 #include <stdio.h> 32 #include <string.h> 33 34 #ifdef SPRINTF_CHAR 35 # define SPRINTF(x) strlen(sprintf/**/x) 36 #else 37 # define SPRINTF(x) ((size_t)sprintf x) 38 #endif 39 40 /*% 41 * WARNING: Don't even consider trying to compile this on a system where 42 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 43 */ 44 45 static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); 46 static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size)); 47 48 /* char * 49 * inet_ntop(af, src, dst, size) 50 * convert a network format address to presentation format. 51 * return: 52 * pointer to presentation format address (`dst'), or NULL (see errno). 53 * author: 54 * Paul Vixie, 1996. 55 */ 56 const char * 57 inet_ntop(af, src, dst, size) 58 int af; 59 const void *src; 60 char *dst; 61 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(src, dst, size) 88 const u_char *src; 89 char *dst; 90 size_t size; 91 { 92 static const char fmt[] = "%u.%u.%u.%u"; 93 char tmp[sizeof "255.255.255.255"]; 94 95 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) >= size) { 96 errno = ENOSPC; 97 return (NULL); 98 } 99 strcpy(dst, tmp); 100 return (dst); 101 } 102 103 /* const char * 104 * inet_ntop6(src, dst, size) 105 * convert IPv6 binary address into presentation (printable) format 106 * author: 107 * Paul Vixie, 1996. 108 */ 109 static const char * 110 inet_ntop6(src, dst, size) 111 const u_char *src; 112 char *dst; 113 size_t size; 114 { 115 /* 116 * Note that int32_t and int16_t need only be "at least" large enough 117 * to contain a value of the specified size. On some systems, like 118 * Crays, there is no such thing as an integer variable with 16 bits. 119 * Keep this in mind if you think this function should have been coded 120 * to use pointer overlays. All the world's not a VAX. 121 */ 122 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 123 struct { int base, len; } best, cur; 124 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 125 int i; 126 127 /* 128 * Preprocess: 129 * Copy the input (bytewise) array into a wordwise array. 130 * Find the longest run of 0x00's in src[] for :: shorthanding. 131 */ 132 memset(words, '\0', sizeof words); 133 for (i = 0; i < NS_IN6ADDRSZ; i++) 134 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 135 best.base = -1; 136 best.len = 0; 137 cur.base = -1; 138 cur.len = 0; 139 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 140 if (words[i] == 0) { 141 if (cur.base == -1) 142 cur.base = i, cur.len = 1; 143 else 144 cur.len++; 145 } else { 146 if (cur.base != -1) { 147 if (best.base == -1 || cur.len > best.len) 148 best = cur; 149 cur.base = -1; 150 } 151 } 152 } 153 if (cur.base != -1) { 154 if (best.base == -1 || cur.len > best.len) 155 best = cur; 156 } 157 if (best.base != -1 && best.len < 2) 158 best.base = -1; 159 160 /* 161 * Format the result. 162 */ 163 tp = tmp; 164 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 165 /* Are we inside the best run of 0x00's? */ 166 if (best.base != -1 && i >= best.base && 167 i < (best.base + best.len)) { 168 if (i == best.base) 169 *tp++ = ':'; 170 continue; 171 } 172 /* Are we following an initial run of 0x00s or any real hex? */ 173 if (i != 0) 174 *tp++ = ':'; 175 /* Is this address an encapsulated IPv4? */ 176 if (i == 6 && best.base == 0 && (best.len == 6 || 177 (best.len == 7 && words[7] != 0x0001) || 178 (best.len == 5 && words[5] == 0xffff))) { 179 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 180 return (NULL); 181 tp += strlen(tp); 182 break; 183 } 184 tp += SPRINTF((tp, "%x", words[i])); 185 } 186 /* Was it a trailing run of 0x00's? */ 187 if (best.base != -1 && (best.base + best.len) == 188 (NS_IN6ADDRSZ / NS_INT16SZ)) 189 *tp++ = ':'; 190 *tp++ = '\0'; 191 192 /* 193 * Check for overflow, copy, and we're done. 194 */ 195 if ((size_t)(tp - tmp) > size) { 196 errno = ENOSPC; 197 return (NULL); 198 } 199 strcpy(dst, tmp); 200 return (dst); 201 } 202 203