1/* Copyright (c) 1996 by Internet Software Consortium. 2 * 3 * Permission to use, copy, modify, and distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 8 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 9 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 10 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 11 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 12 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 13 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 14 * SOFTWARE. 15 */ 16 17#if defined(LIBC_SCCS) && !defined(lint) 18static char rcsid[] = "$Id: inet_ntop.c,v 1.1.1.1 2008/10/15 03:28:56 james26_jang Exp $"; 19#endif /* LIBC_SCCS and not lint */ 20 21#include <sys/param.h> 22#include <sys/types.h> 23#include <sys/socket.h> 24#include <netinet/in.h> 25#include <arpa/inet.h> 26#include <arpa/nameser.h> 27#include <string.h> 28#include <errno.h> 29#include <stdio.h> 30 31#include <linux/in6.h> 32#define IN6ADDRSZ sizeof(struct in6_addr) 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 45static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); 46static 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 */ 56const char * 57inet_ntop(af, src, dst, size) 58 int af; 59 const void *src; 60 char *dst; 61 size_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, more or less like inet_ntoa() 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 */ 86static const char * 87inet_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 */ 109static const char * 110inet_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[sizeof(struct in6_addr) / 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 < IN6ADDRSZ; i++) 134 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 135 best.base = -1; 136 cur.base = -1; 137 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 138 if (words[i] == 0) { 139 if (cur.base == -1) 140 cur.base = i, cur.len = 1; 141 else 142 cur.len++; 143 } else { 144 if (cur.base != -1) { 145 if (best.base == -1 || cur.len > best.len) 146 best = cur; 147 cur.base = -1; 148 } 149 } 150 } 151 if (cur.base != -1) { 152 if (best.base == -1 || cur.len > best.len) 153 best = cur; 154 } 155 if (best.base != -1 && best.len < 2) 156 best.base = -1; 157 158 /* 159 * Format the result. 160 */ 161 tp = tmp; 162 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 163 /* Are we inside the best run of 0x00's? */ 164 if (best.base != -1 && i >= best.base && 165 i < (best.base + best.len)) { 166 if (i == best.base) 167 *tp++ = ':'; 168 continue; 169 } 170 /* Are we following an initial run of 0x00s or any real hex? */ 171 if (i != 0) 172 *tp++ = ':'; 173 /* Is this address an encapsulated IPv4? */ 174 if (i == 6 && best.base == 0 && 175 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 176 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 177 return (NULL); 178 tp += strlen(tp); 179 break; 180 } 181 tp += SPRINTF((tp, "%x", words[i])); 182 } 183 /* Was it a trailing run of 0x00's? */ 184 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 185 *tp++ = ':'; 186 *tp++ = '\0'; 187 188 /* 189 * Check for overflow, copy, and we're done. 190 */ 191 if ((size_t)(tp - tmp) > size) { 192 errno = (ENOSPC); 193 return (NULL); 194 } 195 strcpy(dst, tmp); 196 return (dst); 197} 198