1 /* 2 * Copyright (c) 1999 Kungliga Tekniska Högskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the Kungliga Tekniska 20 * Högskolan and its contributors. 21 * 22 * 4. Neither the name of the Institute nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifdef HAVE_CONFIG_H 40 #include <config.h> 41 #endif 42 43 #include "netdissect-stdinc.h" 44 #include "addrtostr.h" 45 46 #include <stdio.h> 47 #include <string.h> 48 49 /* 50 * 51 */ 52 53 #ifndef IN6ADDRSZ 54 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 55 #endif 56 57 #ifndef INT16SZ 58 #define INT16SZ 2 /* word size */ 59 #endif 60 61 const char * 62 addrtostr (const void *src, char *dst, size_t size) 63 { 64 const u_char *srcaddr = (const u_char *)src; 65 const char digits[] = "0123456789"; 66 int i; 67 const char *orig_dst = dst; 68 69 if (size < INET_ADDRSTRLEN) { 70 errno = ENOSPC; 71 return NULL; 72 } 73 for (i = 0; i < 4; ++i) { 74 int n = *srcaddr++; 75 int non_zerop = 0; 76 77 if (non_zerop || n / 100 > 0) { 78 *dst++ = digits[n / 100]; 79 n %= 100; 80 non_zerop = 1; 81 } 82 if (non_zerop || n / 10 > 0) { 83 *dst++ = digits[n / 10]; 84 n %= 10; 85 non_zerop = 1; 86 } 87 *dst++ = digits[n]; 88 if (i != 3) 89 *dst++ = '.'; 90 } 91 *dst++ = '\0'; 92 return orig_dst; 93 } 94 95 /* 96 * Convert IPv6 binary address into presentation (printable) format. 97 */ 98 const char * 99 addrtostr6 (const void *src, char *dst, size_t size) 100 { 101 /* 102 * Note that int32_t and int16_t need only be "at least" large enough 103 * to contain a value of the specified size. On some systems, like 104 * Crays, there is no such thing as an integer variable with 16 bits. 105 * Keep this in mind if you think this function should have been coded 106 * to use pointer overlays. All the world's not a VAX. 107 */ 108 const u_char *srcaddr = (const u_char *)src; 109 char *dp; 110 size_t space_left, added_space; 111 int snprintfed; 112 struct { 113 int base; 114 int len; 115 } best, cur; 116 uint16_t words [IN6ADDRSZ / INT16SZ]; 117 int i; 118 119 /* Preprocess: 120 * Copy the input (bytewise) array into a wordwise array. 121 * Find the longest run of 0x00's in src[] for :: shorthanding. 122 */ 123 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) 124 words[i] = (srcaddr[2*i] << 8) | srcaddr[2*i + 1]; 125 126 best.len = 0; 127 best.base = -1; 128 cur.len = 0; 129 cur.base = -1; 130 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) 131 { 132 if (words[i] == 0) 133 { 134 if (cur.base == -1) 135 cur.base = i, cur.len = 1; 136 else cur.len++; 137 } 138 else if (cur.base != -1) 139 { 140 if (best.base == -1 || cur.len > best.len) 141 best = cur; 142 cur.base = -1; 143 } 144 } 145 if ((cur.base != -1) && (best.base == -1 || cur.len > best.len)) 146 best = cur; 147 if (best.base != -1 && best.len < 2) 148 best.base = -1; 149 150 /* Format the result. 151 */ 152 dp = dst; 153 space_left = size; 154 #define APPEND_CHAR(c) \ 155 { \ 156 if (space_left == 0) { \ 157 errno = ENOSPC; \ 158 return (NULL); \ 159 } \ 160 *dp++ = c; \ 161 space_left--; \ 162 } 163 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) 164 { 165 /* Are we inside the best run of 0x00's? 166 */ 167 if (best.base != -1 && i >= best.base && i < (best.base + best.len)) 168 { 169 if (i == best.base) 170 APPEND_CHAR(':'); 171 continue; 172 } 173 174 /* Are we following an initial run of 0x00s or any real hex? 175 */ 176 if (i != 0) 177 APPEND_CHAR(':'); 178 179 /* Is this address an encapsulated IPv4? 180 */ 181 if (i == 6 && best.base == 0 && 182 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) 183 { 184 if (!addrtostr(srcaddr+12, dp, space_left)) 185 { 186 errno = ENOSPC; 187 return (NULL); 188 } 189 added_space = strlen(dp); 190 dp += added_space; 191 space_left -= added_space; 192 break; 193 } 194 snprintfed = snprintf (dp, space_left, "%x", words[i]); 195 if (snprintfed < 0) 196 return (NULL); 197 if ((size_t) snprintfed >= space_left) 198 { 199 errno = ENOSPC; 200 return (NULL); 201 } 202 dp += snprintfed; 203 space_left -= snprintfed; 204 } 205 206 /* Was it a trailing run of 0x00's? 207 */ 208 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 209 APPEND_CHAR(':'); 210 APPEND_CHAR('\0'); 211 212 return (dst); 213 } 214