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 const char * 53 inet_ntop(int af, const void *src, char *dst, socklen_t size) 54 { 55 56 switch (af) { 57 case AF_INET: 58 return (inet_ntop4(src, dst, size)); 59 #ifdef INET6 60 case AF_INET6: 61 return (inet_ntop6(src, dst, size)); 62 #endif 63 default: 64 WSASetLastError(WSAEAFNOSUPPORT); 65 return (NULL); 66 } 67 /* NOTREACHED */ 68 } 69 70 /* const char * 71 * inet_ntop4(src, dst, size) 72 * format an IPv4 address, more or less like inet_ntoa() 73 * return: 74 * `dst' (as a const) 75 * notes: 76 * (1) uses no statics 77 * (2) takes a u_char* not an in_addr as input 78 * author: 79 * Paul Vixie, 1996. 80 */ 81 static const char * 82 inet_ntop4(const u_char *src, char *dst, socklen_t size) 83 { 84 static const char fmt[] = "%u.%u.%u.%u"; 85 char tmp[sizeof "255.255.255.255"]; 86 87 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { 88 WSASetLastError(WSAEINVAL); 89 return (NULL); 90 } 91 strcpy(dst, tmp); 92 return (dst); 93 } 94 95 #ifdef INET6 96 /* const char * 97 * inet_ntop6(src, dst, size) 98 * convert IPv6 binary address into presentation (printable) format 99 * author: 100 * Paul Vixie, 1996. 101 */ 102 static const char * 103 inet_ntop6(const u_char *src, char *dst, socklen_t size) 104 { 105 /* 106 * Note that int32_t and int16_t need only be "at least" large enough 107 * to contain a value of the specified size. On some systems, like 108 * Crays, there is no such thing as an integer variable with 16 bits. 109 * Keep this in mind if you think this function should have been coded 110 * to use pointer overlays. All the world's not a VAX. 111 */ 112 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 113 struct { int base, len; } best, cur; 114 u_int words[IN6ADDRSZ / INT16SZ]; 115 int i; 116 117 /* 118 * Preprocess: 119 * Copy the input (bytewise) array into a wordwise array. 120 * Find the longest run of 0x00's in src[] for :: shorthanding. 121 */ 122 memset(words, '\0', sizeof words); 123 for (i = 0; i < IN6ADDRSZ; i++) 124 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 125 best.base = -1; 126 cur.base = -1; 127 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 128 if (words[i] == 0) { 129 if (cur.base == -1) 130 cur.base = i, cur.len = 1; 131 else 132 cur.len++; 133 } else { 134 if (cur.base != -1) { 135 if (best.base == -1 || cur.len > best.len) 136 best = cur; 137 cur.base = -1; 138 } 139 } 140 } 141 if (cur.base != -1) { 142 if (best.base == -1 || cur.len > best.len) 143 best = cur; 144 } 145 if (best.base != -1 && best.len < 2) 146 best.base = -1; 147 148 /* 149 * Format the result. 150 */ 151 tp = tmp; 152 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 153 /* Are we inside the best run of 0x00's? */ 154 if (best.base != -1 && i >= best.base && 155 i < (best.base + best.len)) { 156 if (i == best.base) 157 *tp++ = ':'; 158 continue; 159 } 160 /* Are we following an initial run of 0x00s or any real hex? */ 161 if (i != 0) 162 *tp++ = ':'; 163 /* Is this address an encapsulated IPv4? */ 164 if (i == 6 && best.base == 0 && 165 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 166 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 167 return (NULL); 168 tp += strlen(tp); 169 break; 170 } 171 tp += SPRINTF((tp, "%x", words[i])); 172 } 173 /* Was it a trailing run of 0x00's? */ 174 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 175 *tp++ = ':'; 176 *tp++ = '\0'; 177 178 /* 179 * Check for overflow, copy, and we're done. 180 */ 181 if ((socklen_t)(tp - tmp) > size) { 182 WSASetLastError(WSAEINVAL); 183 return (NULL); 184 } 185 strcpy(dst, tmp); 186 return (dst); 187 } 188 #endif 189 190