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 * $Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp $ 18 */ 19 20 #include "port_before.h" 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 #include "port_after.h" 35 36 /*% 37 * WARNING: Don't even consider trying to compile this on a system where 38 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 39 */ 40 41 static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 42 static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 43 44 /* const char * 45 * inet_ntop(af, src, dst, size) 46 * convert a network format address to presentation format. 47 * return: 48 * pointer to presentation format address (`dst'), or NULL (see errno). 49 * author: 50 * Paul Vixie, 1996. 51 */ 52 const char * 53 inet_ntop(int af, const void * __restrict src, char * __restrict dst, 54 socklen_t size) 55 { 56 switch (af) { 57 case AF_INET: 58 return (inet_ntop4(src, dst, size)); 59 case AF_INET6: 60 return (inet_ntop6(src, dst, size)); 61 default: 62 errno = EAFNOSUPPORT; 63 return (NULL); 64 } 65 /* NOTREACHED */ 66 } 67 68 /* const char * 69 * inet_ntop4(src, dst, size) 70 * format an IPv4 address 71 * return: 72 * `dst' (as a const) 73 * notes: 74 * (1) uses no statics 75 * (2) takes a u_char* not an in_addr as input 76 * author: 77 * Paul Vixie, 1996. 78 */ 79 static const char * 80 inet_ntop4(const u_char *src, char *dst, size_t size) 81 { 82 static const char fmt[] = "%u.%u.%u.%u"; 83 char tmp[sizeof "255.255.255.255"]; 84 int l; 85 86 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 87 if (l <= 0 || (socklen_t)l >= size) { 88 errno = ENOSPC; 89 return (NULL); 90 } 91 strlcpy(dst, tmp, size); 92 return (dst); 93 } 94 95 /* const char * 96 * inet_ntop6(src, dst, size) 97 * convert IPv6 binary address into presentation (printable) format 98 * author: 99 * Paul Vixie, 1996. 100 */ 101 static const char * 102 inet_ntop6(const u_char *src, char *dst, size_t size) 103 { 104 /* 105 * Note that int32_t and int16_t need only be "at least" large enough 106 * to contain a value of the specified size. On some systems, like 107 * Crays, there is no such thing as an integer variable with 16 bits. 108 * Keep this in mind if you think this function should have been coded 109 * to use pointer overlays. All the world's not a VAX. 110 */ 111 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 112 struct { int base, len; } best, cur; 113 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 114 int i; 115 116 /* 117 * Preprocess: 118 * Copy the input (bytewise) array into a wordwise array. 119 * Find the longest run of 0x00's in src[] for :: shorthanding. 120 */ 121 memset(words, '\0', sizeof words); 122 for (i = 0; i < NS_IN6ADDRSZ; i++) 123 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 124 best.base = -1; 125 best.len = 0; 126 cur.base = -1; 127 cur.len = 0; 128 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 129 if (words[i] == 0) { 130 if (cur.base == -1) 131 cur.base = i, cur.len = 1; 132 else 133 cur.len++; 134 } else { 135 if (cur.base != -1) { 136 if (best.base == -1 || cur.len > best.len) 137 best = cur; 138 cur.base = -1; 139 } 140 } 141 } 142 if (cur.base != -1) { 143 if (best.base == -1 || cur.len > best.len) 144 best = cur; 145 } 146 if (best.base != -1 && best.len < 2) 147 best.base = -1; 148 149 /* 150 * Format the result. 151 */ 152 tp = tmp; 153 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 154 /* Are we inside the best run of 0x00's? */ 155 if (best.base != -1 && i >= best.base && 156 i < (best.base + best.len)) { 157 if (i == best.base) 158 *tp++ = ':'; 159 continue; 160 } 161 /* Are we following an initial run of 0x00s or any real hex? */ 162 if (i != 0) 163 *tp++ = ':'; 164 /* Is this address an encapsulated IPv4? */ 165 if (i == 6 && best.base == 0 && (best.len == 6 || 166 (best.len == 7 && words[7] != 0x0001) || 167 (best.len == 5 && words[5] == 0xffff))) { 168 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) { 169 errno = ENOSPC; 170 return (NULL); 171 } 172 tp += strlen(tp); 173 break; 174 } 175 tp += sprintf(tp, "%x", words[i]); 176 } 177 /* Was it a trailing run of 0x00's? */ 178 if (best.base != -1 && (best.base + best.len) == 179 (NS_IN6ADDRSZ / NS_INT16SZ)) 180 *tp++ = ':'; 181 *tp++ = '\0'; 182 183 /* 184 * Check for overflow, copy, and we're done. 185 */ 186 if ((socklen_t)(tp - tmp) > size) { 187 errno = ENOSPC; 188 return (NULL); 189 } 190 strcpy(dst, tmp); 191 return (dst); 192 } 193 194 /* 195 * Weak aliases for applications that use certain private entry points, 196 * and fail to include <arpa/inet.h>. 197 */ 198 #undef inet_ntop 199 __weak_reference(__inet_ntop, inet_ntop); 200