1 /* from NetBSD: inet_ntop.c,v 1.9 2000/01/22 22:19:16 mycroft Exp */ 2 3 /* Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS 10 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 11 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 12 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 13 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 14 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 15 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 16 * SOFTWARE. 17 */ 18 19 #include <stdio.h> 20 21 #ifndef IN6ADDRSZ 22 #define IN6ADDRSZ 16 23 #endif 24 25 #ifndef INT16SZ 26 #define INT16SZ 2 27 #endif 28 29 #ifdef SPRINTF_CHAR 30 # define SPRINTF(x) strlen(sprintf/**/x) 31 #else 32 # define SPRINTF(x) ((size_t)sprintf x) 33 #endif 34 35 /* 36 * WARNING: Don't even consider trying to compile this on a system where 37 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 38 */ 39 40 static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 41 42 #ifdef INET6 43 static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 44 #endif 45 46 /* char * 47 * inet_ntop(af, src, dst, size) 48 * convert a network format address to presentation format. 49 * return: 50 * pointer to presentation format address (`dst'), or NULL (see errno). 51 * author: 52 * Paul Vixie, 1996. 53 */ 54 55 PCSTR 56 WSAAPI 57 inet_ntop(INT Family, PVOID pAddr, PSTR pStringBuf, size_t StringBufSize) 58 { 59 60 switch (Family) { 61 case AF_INET: 62 return (inet_ntop4(pAddr, pStringBuf, StringBufSize)); 63 #ifdef INET6 64 case AF_INET6: 65 return (inet_ntop6(pAddr, pStringBuf, StringBufSize)); 66 #endif 67 default: 68 WSASetLastError(WSAEAFNOSUPPORT); 69 return (NULL); 70 } 71 /* NOTREACHED */ 72 } 73 74 /* const char * 75 * inet_ntop4(src, dst, size) 76 * format an IPv4 address, more or less like inet_ntoa() 77 * return: 78 * `dst' (as a const) 79 * notes: 80 * (1) uses no statics 81 * (2) takes a u_char* not an in_addr as input 82 * author: 83 * Paul Vixie, 1996. 84 */ 85 static const char * 86 inet_ntop4(const u_char *src, char *dst, size_t size) 87 { 88 static const char fmt[] = "%u.%u.%u.%u"; 89 char tmp[sizeof "255.255.255.255"]; 90 91 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { 92 WSASetLastError(WSAEINVAL); 93 return (NULL); 94 } 95 strcpy(dst, tmp); 96 return (dst); 97 } 98 99 #ifdef INET6 100 /* const char * 101 * inet_ntop6(src, dst, size) 102 * convert IPv6 binary address into presentation (printable) format 103 * author: 104 * Paul Vixie, 1996. 105 */ 106 static const char * 107 inet_ntop6(const u_char *src, char *dst, size_t size) 108 { 109 /* 110 * Note that int32_t and int16_t need only be "at least" large enough 111 * to contain a value of the specified size. On some systems, like 112 * Crays, there is no such thing as an integer variable with 16 bits. 113 * Keep this in mind if you think this function should have been coded 114 * to use pointer overlays. All the world's not a VAX. 115 */ 116 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 117 struct { int base, len; } best, cur; 118 u_int words[IN6ADDRSZ / INT16SZ]; 119 int i; 120 121 /* 122 * Preprocess: 123 * Copy the input (bytewise) array into a wordwise array. 124 * Find the longest run of 0x00's in src[] for :: shorthanding. 125 */ 126 memset(words, '\0', sizeof words); 127 for (i = 0; i < IN6ADDRSZ; i++) 128 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 129 best.base = -1; 130 cur.base = -1; 131 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 132 if (words[i] == 0) { 133 if (cur.base == -1) 134 cur.base = i, cur.len = 1; 135 else 136 cur.len++; 137 } else { 138 if (cur.base != -1) { 139 if (best.base == -1 || cur.len > best.len) 140 best = cur; 141 cur.base = -1; 142 } 143 } 144 } 145 if (cur.base != -1) { 146 if (best.base == -1 || cur.len > best.len) 147 best = cur; 148 } 149 if (best.base != -1 && best.len < 2) 150 best.base = -1; 151 152 /* 153 * Format the result. 154 */ 155 tp = tmp; 156 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 157 /* Are we inside the best run of 0x00's? */ 158 if (best.base != -1 && i >= best.base && 159 i < (best.base + best.len)) { 160 if (i == best.base) 161 *tp++ = ':'; 162 continue; 163 } 164 /* Are we following an initial run of 0x00s or any real hex? */ 165 if (i != 0) 166 *tp++ = ':'; 167 /* Is this address an encapsulated IPv4? */ 168 if (i == 6 && best.base == 0 && 169 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 170 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 171 return (NULL); 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) == (IN6ADDRSZ / INT16SZ)) 179 *tp++ = ':'; 180 *tp++ = '\0'; 181 182 /* 183 * Check for overflow, copy, and we're done. 184 */ 185 if ((size_t)(tp - tmp) > size) { 186 WSASetLastError(WSAEINVAL); 187 return (NULL); 188 } 189 strcpy(dst, tmp); 190 return (dst); 191 } 192 #endif 193 194