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 #include <config.h> 40 41 #include "netdissect-stdinc.h" 42 #include "addrtostr.h" 43 44 #include <stdio.h> 45 #include <string.h> 46 47 /* 48 * 49 */ 50 51 #ifndef IN6ADDRSZ 52 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 53 #endif 54 55 #ifndef INT16SZ 56 #define INT16SZ 2 /* word size */ 57 #endif 58 59 const char * 60 addrtostr (const void *src, char *dst, size_t size) 61 { 62 const u_char *srcaddr = (const u_char *)src; 63 const char digits[] = "0123456789"; 64 int i; 65 const char *orig_dst = dst; 66 67 if (size < INET_ADDRSTRLEN) { 68 errno = ENOSPC; 69 return NULL; 70 } 71 for (i = 0; i < 4; ++i) { 72 int n = *srcaddr++; 73 int non_zerop = 0; 74 75 if (non_zerop || n / 100 > 0) { 76 *dst++ = digits[n / 100]; 77 n %= 100; 78 non_zerop = 1; 79 } 80 if (non_zerop || n / 10 > 0) { 81 *dst++ = digits[n / 10]; 82 n %= 10; 83 non_zerop = 1; 84 } 85 *dst++ = digits[n]; 86 if (i != 3) 87 *dst++ = '.'; 88 } 89 *dst++ = '\0'; 90 return orig_dst; 91 } 92 93 /* 94 * Convert IPv6 binary address into presentation (printable) format. 95 */ 96 const char * 97 addrtostr6 (const void *src, char *dst, size_t size) 98 { 99 /* 100 * Note that int32_t and int16_t need only be "at least" large enough 101 * to contain a value of the specified size. On some systems, like 102 * Crays, there is no such thing as an integer variable with 16 bits. 103 * Keep this in mind if you think this function should have been coded 104 * to use pointer overlays. All the world's not a VAX. 105 */ 106 const u_char *srcaddr = (const u_char *)src; 107 char *dp; 108 size_t space_left, added_space; 109 int snprintfed; 110 struct { 111 int base; 112 int len; 113 } best, cur; 114 uint16_t words [IN6ADDRSZ / INT16SZ]; 115 int i; 116 117 /* Preprocess: 118 * Copy the input (bytewise) array into a wordwise array. 119 * Find the longest run of 0x00's in src[] for :: shorthanding. 120 */ 121 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) 122 words[i] = (srcaddr[2*i] << 8) | srcaddr[2*i + 1]; 123 124 best.len = 0; 125 best.base = -1; 126 cur.len = 0; 127 cur.base = -1; 128 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 129 if (words[i] == 0) { 130 if (cur.base == -1) 131 cur.base = i, cur.len = 1; 132 else cur.len++; 133 } else if (cur.base != -1) { 134 if (best.base == -1 || cur.len > best.len) 135 best = cur; 136 cur.base = -1; 137 } 138 } 139 if ((cur.base != -1) && (best.base == -1 || cur.len > best.len)) 140 best = cur; 141 if (best.base != -1 && best.len < 2) 142 best.base = -1; 143 144 /* Format the result. 145 */ 146 dp = dst; 147 space_left = size; 148 #define APPEND_CHAR(c) \ 149 { \ 150 if (space_left == 0) { \ 151 errno = ENOSPC; \ 152 return (NULL); \ 153 } \ 154 *dp++ = c; \ 155 space_left--; \ 156 } 157 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 158 /* Are we inside the best run of 0x00's? 159 */ 160 if (best.base != -1 && i >= best.base && i < (best.base + best.len)) { 161 if (i == best.base) 162 APPEND_CHAR(':'); 163 continue; 164 } 165 166 /* Are we following an initial run of 0x00s or any real hex? 167 */ 168 if (i != 0) 169 APPEND_CHAR(':'); 170 171 /* Is this address an encapsulated IPv4? 172 */ 173 if (i == 6 && best.base == 0 && 174 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) 175 { 176 if (!addrtostr(srcaddr+12, dp, space_left)) { 177 errno = ENOSPC; 178 return (NULL); 179 } 180 added_space = strlen(dp); 181 dp += added_space; 182 space_left -= added_space; 183 break; 184 } 185 snprintfed = snprintf (dp, space_left, "%x", words[i]); 186 if (snprintfed < 0) 187 return (NULL); 188 if ((size_t) snprintfed >= space_left) { 189 errno = ENOSPC; 190 return (NULL); 191 } 192 dp += snprintfed; 193 space_left -= snprintfed; 194 } 195 196 /* Was it a trailing run of 0x00's? 197 */ 198 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 199 APPEND_CHAR(':'); 200 APPEND_CHAR('\0'); 201 202 return (dst); 203 } 204