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 #ifndef IN6ADDRSZ 20 #define IN6ADDRSZ 16 21 #endif 22 23 #ifndef INT16SZ 24 #define INT16SZ 2 25 #endif 26 27 #ifdef SPRINTF_CHAR 28 # define SPRINTF(x) strlen(sprintf/**/x) 29 #else 30 # define SPRINTF(x) ((socklen_t)sprintf x) 31 #endif 32 33 /* 34 * WARNING: Don't even consider trying to compile this on a system where 35 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 36 */ 37 38 static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size); 39 40 #ifdef INET6 41 static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size); 42 #endif 43 44 /* 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 PCSTR 53 WSAAPI 54 inet_ntop( 55 _In_ INT af, 56 _In_ const VOID *src, 57 _Out_writes_(StringBufSize) PSTR dst, 58 _In_ size_t size) 59 { 60 61 switch (af) { 62 case AF_INET: 63 return (inet_ntop4(src, dst, size)); 64 #ifdef INET6 65 case AF_INET6: 66 return (inet_ntop6(src, dst, size)); 67 #endif 68 default: 69 WSASetLastError(WSAEAFNOSUPPORT); 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 */ 86 static const char * 87 inet_ntop4(const u_char *src, char *dst, socklen_t size) 88 { 89 static const char fmt[] = "%u.%u.%u.%u"; 90 char tmp[sizeof "255.255.255.255"]; 91 92 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { 93 WSASetLastError(WSAEINVAL); 94 return (NULL); 95 } 96 strcpy(dst, tmp); 97 return (dst); 98 } 99 100 #ifdef INET6 101 /* const char * 102 * inet_ntop6(src, dst, size) 103 * convert IPv6 binary address into presentation (printable) format 104 * author: 105 * Paul Vixie, 1996. 106 */ 107 static const char * 108 inet_ntop6(const u_char *src, char *dst, socklen_t size) 109 { 110 /* 111 * Note that int32_t and int16_t need only be "at least" large enough 112 * to contain a value of the specified size. On some systems, like 113 * Crays, there is no such thing as an integer variable with 16 bits. 114 * Keep this in mind if you think this function should have been coded 115 * to use pointer overlays. All the world's not a VAX. 116 */ 117 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 118 struct { int base, len; } best, cur; 119 u_int words[IN6ADDRSZ / INT16SZ]; 120 int i; 121 122 /* 123 * Preprocess: 124 * Copy the input (bytewise) array into a wordwise array. 125 * Find the longest run of 0x00's in src[] for :: shorthanding. 126 */ 127 memset(words, '\0', sizeof words); 128 for (i = 0; i < IN6ADDRSZ; i++) 129 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 130 best.base = -1; 131 cur.base = -1; 132 for (i = 0; i < (IN6ADDRSZ / 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 < (IN6ADDRSZ / 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 && 170 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 171 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 172 return (NULL); 173 tp += strlen(tp); 174 break; 175 } 176 tp += SPRINTF((tp, "%x", words[i])); 177 } 178 /* Was it a trailing run of 0x00's? */ 179 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / 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 WSASetLastError(WSAEINVAL); 188 return (NULL); 189 } 190 strcpy(dst, tmp); 191 return (dst); 192 } 193 #endif 194 195