1/* 2 * Copyright (C) 1996-2022 Internet Software Consortium. 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM 9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL 10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL 11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING 13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 * 17 * SPDX-License-Identifier: ISC 18 */ 19/* 20 * Original code by Paul Vixie. "curlified" by Gisle Vanem. 21 */ 22 23#include "curl_setup.h" 24 25#ifndef HAVE_INET_NTOP 26 27#ifdef HAVE_SYS_PARAM_H 28#include <sys/param.h> 29#endif 30#ifdef HAVE_NETINET_IN_H 31#include <netinet/in.h> 32#endif 33#ifdef HAVE_ARPA_INET_H 34#include <arpa/inet.h> 35#endif 36 37#include "inet_ntop.h" 38#include "curl_printf.h" 39 40#define IN6ADDRSZ 16 41#define INADDRSZ 4 42#define INT16SZ 2 43 44/* 45 * If ENABLE_IPV6 is disabled, we still want to parse IPv6 addresses, so make 46 * sure we have _some_ value for AF_INET6 without polluting our fake value 47 * everywhere. 48 */ 49#if !defined(ENABLE_IPV6) && !defined(AF_INET6) 50#define AF_INET6 (AF_INET + 1) 51#endif 52 53/* 54 * Format an IPv4 address, more or less like inet_ntop(). 55 * 56 * Returns `dst' (as a const) 57 * Note: 58 * - uses no statics 59 * - takes a unsigned char* not an in_addr as input 60 */ 61static char *inet_ntop4 (const unsigned char *src, char *dst, size_t size) 62{ 63 char tmp[sizeof("255.255.255.255")]; 64 size_t len; 65 66 DEBUGASSERT(size >= 16); 67 68 tmp[0] = '\0'; 69 (void)msnprintf(tmp, sizeof(tmp), "%d.%d.%d.%d", 70 ((int)((unsigned char)src[0])) & 0xff, 71 ((int)((unsigned char)src[1])) & 0xff, 72 ((int)((unsigned char)src[2])) & 0xff, 73 ((int)((unsigned char)src[3])) & 0xff); 74 75 len = strlen(tmp); 76 if(len == 0 || len >= size) { 77 errno = ENOSPC; 78 return (NULL); 79 } 80 strcpy(dst, tmp); 81 return dst; 82} 83 84/* 85 * Convert IPv6 binary address into presentation (printable) format. 86 */ 87static char *inet_ntop6 (const unsigned char *src, char *dst, size_t size) 88{ 89 /* 90 * Note that int32_t and int16_t need only be "at least" large enough 91 * to contain a value of the specified size. On some systems, like 92 * Crays, there is no such thing as an integer variable with 16 bits. 93 * Keep this in mind if you think this function should have been coded 94 * to use pointer overlays. All the world's not a VAX. 95 */ 96 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")]; 97 char *tp; 98 struct { 99 int base; 100 int len; 101 } best, cur; 102 unsigned int words[IN6ADDRSZ / INT16SZ]; 103 int i; 104 105 /* Preprocess: 106 * Copy the input (bytewise) array into a wordwise array. 107 * Find the longest run of 0x00's in src[] for :: shorthanding. 108 */ 109 memset(words, '\0', sizeof(words)); 110 for(i = 0; i < IN6ADDRSZ; i++) 111 words[i/2] |= ((unsigned int)src[i] << ((1 - (i % 2)) << 3)); 112 113 best.base = -1; 114 cur.base = -1; 115 best.len = 0; 116 cur.len = 0; 117 118 for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 119 if(words[i] == 0) { 120 if(cur.base == -1) { 121 cur.base = i; cur.len = 1; 122 } 123 else 124 cur.len++; 125 } 126 else if(cur.base != -1) { 127 if(best.base == -1 || cur.len > best.len) 128 best = cur; 129 cur.base = -1; 130 } 131 } 132 if((cur.base != -1) && (best.base == -1 || cur.len > best.len)) 133 best = cur; 134 if(best.base != -1 && best.len < 2) 135 best.base = -1; 136 /* Format the result. */ 137 tp = tmp; 138 for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 139 /* Are we inside the best run of 0x00's? */ 140 if(best.base != -1 && i >= best.base && i < (best.base + best.len)) { 141 if(i == best.base) 142 *tp++ = ':'; 143 continue; 144 } 145 146 /* Are we following an initial run of 0x00s or any real hex? 147 */ 148 if(i) 149 *tp++ = ':'; 150 151 /* Is this address an encapsulated IPv4? 152 */ 153 if(i == 6 && best.base == 0 && 154 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 155 if(!inet_ntop4(src + 12, tp, sizeof(tmp) - (tp - tmp))) { 156 errno = ENOSPC; 157 return (NULL); 158 } 159 tp += strlen(tp); 160 break; 161 } 162 tp += msnprintf(tp, 5, "%x", words[i]); 163 } 164 165 /* Was it a trailing run of 0x00's? 166 */ 167 if(best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) 168 *tp++ = ':'; 169 *tp++ = '\0'; 170 171 /* Check for overflow, copy, and we're done. 172 */ 173 if((size_t)(tp - tmp) > size) { 174 errno = ENOSPC; 175 return (NULL); 176 } 177 strcpy(dst, tmp); 178 return dst; 179} 180 181/* 182 * Convert a network format address to presentation format. 183 * 184 * Returns pointer to presentation format address (`buf'). 185 * Returns NULL on error and errno set with the specific 186 * error, EAFNOSUPPORT or ENOSPC. 187 * 188 * On Windows we store the error in the thread errno, not 189 * in the winsock error code. This is to avoid losing the 190 * actual last winsock error. So when this function returns 191 * NULL, check errno not SOCKERRNO. 192 */ 193char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size) 194{ 195 switch(af) { 196 case AF_INET: 197 return inet_ntop4((const unsigned char *)src, buf, size); 198 case AF_INET6: 199 return inet_ntop6((const unsigned char *)src, buf, size); 200 default: 201 errno = EAFNOSUPPORT; 202 return NULL; 203 } 204} 205#endif /* HAVE_INET_NTOP */ 206