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 $"; 20 #endif /* LIBC_SCCS and not lint */ 21 #include <sys/cdefs.h> 22 __FBSDID("$FreeBSD$"); 23 24 #include "port_before.h" 25 26 #include <sys/param.h> 27 #include <sys/types.h> 28 #include <sys/socket.h> 29 30 #include <netinet/in.h> 31 #include <arpa/inet.h> 32 #include <arpa/nameser.h> 33 34 #include <errno.h> 35 #include <stdio.h> 36 #include <string.h> 37 38 #include "port_after.h" 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(const u_char *src, char *dst, socklen_t size); 46 static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size); 47 48 /* const 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(int af, const void * __restrict src, char * __restrict dst, 58 socklen_t size) 59 { 60 switch (af) { 61 case AF_INET: 62 return (inet_ntop4(src, dst, size)); 63 case AF_INET6: 64 return (inet_ntop6(src, dst, size)); 65 default: 66 errno = EAFNOSUPPORT; 67 return (NULL); 68 } 69 /* NOTREACHED */ 70 } 71 72 /* const char * 73 * inet_ntop4(src, dst, size) 74 * format an IPv4 address 75 * return: 76 * `dst' (as a const) 77 * notes: 78 * (1) uses no statics 79 * (2) takes a u_char* not an in_addr as input 80 * author: 81 * Paul Vixie, 1996. 82 */ 83 static const char * 84 inet_ntop4(const u_char *src, char *dst, socklen_t size) 85 { 86 static const char fmt[] = "%u.%u.%u.%u"; 87 char tmp[sizeof "255.255.255.255"]; 88 int l; 89 90 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 91 if (l <= 0 || (socklen_t) l >= size) { 92 errno = ENOSPC; 93 return (NULL); 94 } 95 strlcpy(dst, tmp, size); 96 return (dst); 97 } 98 99 /* const char * 100 * inet_ntop6(src, dst, size) 101 * convert IPv6 binary address into presentation (printable) format 102 * author: 103 * Paul Vixie, 1996. 104 */ 105 static const char * 106 inet_ntop6(const u_char *src, char *dst, socklen_t size) 107 { 108 /* 109 * Note that int32_t and int16_t need only be "at least" large enough 110 * to contain a value of the specified size. On some systems, like 111 * Crays, there is no such thing as an integer variable with 16 bits. 112 * Keep this in mind if you think this function should have been coded 113 * to use pointer overlays. All the world's not a VAX. 114 */ 115 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 116 struct { int base, len; } best, cur; 117 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 118 int i; 119 120 /* 121 * Preprocess: 122 * Copy the input (bytewise) array into a wordwise array. 123 * Find the longest run of 0x00's in src[] for :: shorthanding. 124 */ 125 memset(words, '\0', sizeof words); 126 for (i = 0; i < NS_IN6ADDRSZ; i++) 127 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 128 best.base = -1; 129 best.len = 0; 130 cur.base = -1; 131 cur.len = 0; 132 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 133 if (words[i] == 0) { 134 if (cur.base == -1) 135 cur.base = i, cur.len = 1; 136 else 137 cur.len++; 138 } else { 139 if (cur.base != -1) { 140 if (best.base == -1 || cur.len > best.len) 141 best = cur; 142 cur.base = -1; 143 } 144 } 145 } 146 if (cur.base != -1) { 147 if (best.base == -1 || cur.len > best.len) 148 best = cur; 149 } 150 if (best.base != -1 && best.len < 2) 151 best.base = -1; 152 153 /* 154 * Format the result. 155 */ 156 tp = tmp; 157 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 158 /* Are we inside the best run of 0x00's? */ 159 if (best.base != -1 && i >= best.base && 160 i < (best.base + best.len)) { 161 if (i == best.base) 162 *tp++ = ':'; 163 continue; 164 } 165 /* Are we following an initial run of 0x00s or any real hex? */ 166 if (i != 0) 167 *tp++ = ':'; 168 /* Is this address an encapsulated IPv4? */ 169 if (i == 6 && best.base == 0 && (best.len == 6 || 170 (best.len == 7 && words[7] != 0x0001) || 171 (best.len == 5 && words[5] == 0xffff))) { 172 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) { 173 errno = ENOSPC; 174 return (NULL); 175 } 176 tp += strlen(tp); 177 break; 178 } 179 tp += sprintf(tp, "%x", words[i]); 180 } 181 /* Was it a trailing run of 0x00's? */ 182 if (best.base != -1 && (best.base + best.len) == 183 (NS_IN6ADDRSZ / NS_INT16SZ)) 184 *tp++ = ':'; 185 *tp++ = '\0'; 186 187 /* 188 * Check for overflow, copy, and we're done. 189 */ 190 if ((socklen_t)(tp - tmp) > size) { 191 errno = ENOSPC; 192 return (NULL); 193 } 194 strcpy(dst, tmp); 195 return (dst); 196 } 197 198 /* 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); 204 205 /*! \file */ 206