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 <sys/cdefs.h> 40 #ifndef lint 41 __RCSID("$NetBSD: addrtostr.c,v 1.4 2017/09/08 14:01:12 christos Exp $"); 42 #endif 43 44 #ifdef HAVE_CONFIG_H 45 #include "config.h" 46 #endif 47 48 #include <netdissect-stdinc.h> 49 #include "addrtostr.h" 50 51 #include <stdio.h> 52 #include <string.h> 53 54 /* 55 * 56 */ 57 58 #ifndef IN6ADDRSZ 59 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 60 #endif 61 62 #ifndef INT16SZ 63 #define INT16SZ 2 /* word size */ 64 #endif 65 66 const char * 67 addrtostr (const void *src, char *dst, size_t size) 68 { 69 const u_char *srcaddr = (const u_char *)src; 70 const char digits[] = "0123456789"; 71 int i; 72 const char *orig_dst = dst; 73 74 if (size < INET_ADDRSTRLEN) { 75 errno = ENOSPC; 76 return NULL; 77 } 78 for (i = 0; i < 4; ++i) { 79 int n = *srcaddr++; 80 int non_zerop = 0; 81 82 if (non_zerop || n / 100 > 0) { 83 *dst++ = digits[n / 100]; 84 n %= 100; 85 non_zerop = 1; 86 } 87 if (non_zerop || n / 10 > 0) { 88 *dst++ = digits[n / 10]; 89 n %= 10; 90 non_zerop = 1; 91 } 92 *dst++ = digits[n]; 93 if (i != 3) 94 *dst++ = '.'; 95 } 96 *dst++ = '\0'; 97 return orig_dst; 98 } 99 100 /* 101 * Convert IPv6 binary address into presentation (printable) format. 102 */ 103 const char * 104 addrtostr6 (const void *src, char *dst, size_t size) 105 { 106 /* 107 * Note that int32_t and int16_t need only be "at least" large enough 108 * to contain a value of the specified size. On some systems, like 109 * Crays, there is no such thing as an integer variable with 16 bits. 110 * Keep this in mind if you think this function should have been coded 111 * to use pointer overlays. All the world's not a VAX. 112 */ 113 const u_char *srcaddr = (const u_char *)src; 114 char *dp; 115 size_t space_left, added_space; 116 int snprintfed; 117 struct { 118 int base; 119 int len; 120 } best, cur; 121 uint16_t words [IN6ADDRSZ / INT16SZ]; 122 int i; 123 124 /* Preprocess: 125 * Copy the input (bytewise) array into a wordwise array. 126 * Find the longest run of 0x00's in src[] for :: shorthanding. 127 */ 128 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) 129 words[i] = (srcaddr[2*i] << 8) | srcaddr[2*i + 1]; 130 131 best.len = 0; 132 best.base = -1; 133 cur.len = 0; 134 cur.base = -1; 135 for (i = 0; i < (int)(IN6ADDRSZ / INT16SZ); i++) 136 { 137 if (words[i] == 0) 138 { 139 if (cur.base == -1) 140 cur.base = i, cur.len = 1; 141 else cur.len++; 142 } 143 else if (cur.base != -1) 144 { 145 if (best.base == -1 || cur.len > best.len) 146 best = cur; 147 cur.base = -1; 148 } 149 } 150 if ((cur.base != -1) && (best.base == -1 || cur.len > best.len)) 151 best = cur; 152 if (best.base != -1 && best.len < 2) 153 best.base = -1; 154 155 /* Format the result. 156 */ 157 dp = dst; 158 space_left = size; 159 #define APPEND_CHAR(c) \ 160 { \ 161 if (space_left == 0) { \ 162 errno = ENOSPC; \ 163 return (NULL); \ 164 } \ 165 *dp++ = c; \ 166 space_left--; \ 167 } 168 for (i = 0; i < (int)(IN6ADDRSZ / INT16SZ); i++) 169 { 170 /* Are we inside the best run of 0x00's? 171 */ 172 if (best.base != -1 && i >= best.base && i < (best.base + best.len)) 173 { 174 if (i == best.base) 175 APPEND_CHAR(':'); 176 continue; 177 } 178 179 /* Are we following an initial run of 0x00s or any real hex? 180 */ 181 if (i != 0) 182 APPEND_CHAR(':'); 183 184 /* Is this address an encapsulated IPv4? 185 */ 186 if (i == 6 && best.base == 0 && 187 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) 188 { 189 if (!addrtostr(srcaddr+12, dp, space_left)) 190 { 191 errno = ENOSPC; 192 return (NULL); 193 } 194 added_space = strlen(dp); 195 dp += added_space; 196 space_left -= added_space; 197 break; 198 } 199 snprintfed = snprintf (dp, space_left, "%x", words[i]); 200 if (snprintfed < 0) 201 return (NULL); 202 if ((size_t) snprintfed >= space_left) 203 { 204 errno = ENOSPC; 205 return (NULL); 206 } 207 dp += snprintfed; 208 space_left -= snprintfed; 209 } 210 211 /* Was it a trailing run of 0x00's? 212 */ 213 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 214 APPEND_CHAR(':'); 215 APPEND_CHAR('\0'); 216 217 return (dst); 218 } 219