1 /* 2 * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* Copyright (c) 1996 by Internet Software Consortium. 7 * 8 * Permission to use, copy, modify, and distribute this software for any 9 * purpose with or without fee is hereby granted, provided that the above 10 * copyright notice and this permission notice appear in all copies. 11 * 12 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 13 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 14 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 15 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 16 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 17 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 18 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 19 * SOFTWARE. 20 */ 21 #pragma ident "%Z%%M% %I% %E% SMI" 22 23 #include <stdlib.h> 24 #include <ctype.h> 25 #include <string.h> 26 #include <strings.h> 27 #include <netdb.h> 28 #include <stdio.h> 29 #include <arpa/inet.h> 30 #include <netinet/in.h> 31 #include <sys/socket.h> 32 #include <errno.h> 33 34 static const char *inet_ntop4(const u_char *, char *, socklen_t); 35 static const char *inet_ntop6(const u_char *, char *, socklen_t); 36 37 /* char * 38 * inet_ntop(af, src, dst, size) 39 * convert a network format address to presentation format. 40 * return: 41 * pointer to presentation format address (`dst'), or NULL (see errno). 42 */ 43 const char * 44 inet_ntop(int af, const void *src, char *dst, socklen_t size) 45 { 46 switch (af) { 47 case AF_INET: 48 return (inet_ntop4(src, dst, size)); 49 case AF_INET6: 50 return (inet_ntop6(src, dst, size)); 51 default: 52 errno = EAFNOSUPPORT; 53 return (NULL); 54 } 55 /* NOTREACHED */ 56 } 57 58 /* const char * 59 * inet_ntop4(src, dst, size) 60 * format an IPv4 address, more or less like inet_ntoa() 61 * return: 62 * `dst' (as a const) 63 * notes: 64 * (1) uses no statics 65 * (2) takes a u_char* not an in_addr as input 66 */ 67 68 #ifdef SPRINTF_CHAR 69 # define SPRINTF(x) strlen(sprintf/**/x) 70 #else 71 # define SPRINTF(x) ((size_t)sprintf x) 72 #endif 73 74 static const char * 75 inet_ntop4(const u_char *src, char *dst, socklen_t size) 76 { 77 static const char fmt[] = "%u.%u.%u.%u"; 78 char tmp[sizeof "255.255.255.255"]; 79 80 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { 81 errno = ENOSPC; 82 return (NULL); 83 } 84 strcpy(dst, tmp); 85 return (dst); 86 } 87 88 /* const char * 89 * inet_ntop6(src, dst, size) 90 * convert IPv6 binary address into presentation (printable) format 91 */ 92 #define INADDRSZ 4 93 #define IN6ADDRSZ 16 94 #define INT16SZ 2 95 static const char * 96 inet_ntop6(const u_char *src, char *dst, socklen_t size) 97 { 98 /* 99 * Note that int32_t and int16_t need only be "at least" large enough 100 * to contain a value of the specified size. On some systems, like 101 * Crays, there is no such thing as an integer variable with 16 bits. 102 * Keep this in mind if you think this function should have been coded 103 * to use pointer overlays. All the world's not a VAX. 104 */ 105 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 106 struct { int base, len; } best, cur; 107 u_int words[IN6ADDRSZ / INT16SZ]; 108 int i; 109 110 /* 111 * Preprocess: 112 * Copy the input (bytewise) array into a wordwise array. 113 * Find the longest run of 0x00's in src[] for :: shorthanding. 114 */ 115 memset(words, '\0', sizeof words); 116 for (i = 0; i < IN6ADDRSZ; i++) 117 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 118 best.base = -1; 119 cur.base = -1; 120 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 121 if (words[i] == 0) { 122 if (cur.base == -1) 123 cur.base = i, cur.len = 1; 124 else 125 cur.len++; 126 } else { 127 if (cur.base != -1) { 128 if (best.base == -1 || cur.len > best.len) 129 best = cur; 130 cur.base = -1; 131 } 132 } 133 } 134 if (cur.base != -1) { 135 if (best.base == -1 || cur.len > best.len) 136 best = cur; 137 } 138 if (best.base != -1 && best.len < 2) 139 best.base = -1; 140 141 /* 142 * Format the result. 143 */ 144 tp = tmp; 145 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 146 /* Are we inside the best run of 0x00's? */ 147 if (best.base != -1 && i >= best.base && 148 i < (best.base + best.len)) { 149 if (i == best.base) 150 *tp++ = ':'; 151 continue; 152 } 153 /* Are we following an initial run of 0x00s or any real hex? */ 154 if (i != 0) 155 *tp++ = ':'; 156 /* Is this address an encapsulated IPv4? */ 157 if (i == 6 && best.base == 0 && 158 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 159 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 160 return (NULL); 161 tp += strlen(tp); 162 break; 163 } 164 tp += SPRINTF((tp, "%x", words[i])); 165 } 166 /* Was it a trailing run of 0x00's? */ 167 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 168 *tp++ = ':'; 169 *tp++ = '\0'; 170 171 /* 172 * Check for overflow, copy, and we're done. 173 */ 174 if ((int)(tp - tmp) > size) { 175 errno = ENOSPC; 176 return (NULL); 177 } 178 strcpy(dst, tmp); 179 return (dst); 180 } 181 182