1 /*- 2 * SPDX-License-Identifier: ISC 3 * 4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (c) 1998,1999 by Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #if defined(LIBC_SCCS) && !defined(lint) 21 static const char rcsid[] = "$Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp $"; 22 #endif 23 #include <sys/cdefs.h> 24 __FBSDID("$FreeBSD$"); 25 26 #include "port_before.h" 27 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <netinet/in.h> 31 #include <arpa/nameser.h> 32 #include <arpa/inet.h> 33 34 #include <errno.h> 35 #include <stdio.h> 36 #include <string.h> 37 #include <stdlib.h> 38 39 #include "port_after.h" 40 41 #ifdef SPRINTF_CHAR 42 # define SPRINTF(x) strlen(sprintf/**/x) 43 #else 44 # define SPRINTF(x) ((size_t)sprintf x) 45 #endif 46 47 static char * 48 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size); 49 static char * 50 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size); 51 52 /*% 53 * char * 54 * inet_cidr_ntop(af, src, bits, dst, size) 55 * convert network address from network to presentation format. 56 * "src"'s size is determined from its "af". 57 * return: 58 * pointer to dst, or NULL if an error occurred (check errno). 59 * note: 60 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network 61 * as called for by inet_net_ntop() but it can be a host address with 62 * an included netmask. 63 * author: 64 * Paul Vixie (ISC), October 1998 65 */ 66 char * 67 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) { 68 switch (af) { 69 case AF_INET: 70 return (inet_cidr_ntop_ipv4(src, bits, dst, size)); 71 case AF_INET6: 72 return (inet_cidr_ntop_ipv6(src, bits, dst, size)); 73 default: 74 errno = EAFNOSUPPORT; 75 return (NULL); 76 } 77 } 78 79 static int 80 decoct(const u_char *src, int bytes, char *dst, size_t size) { 81 char *odst = dst; 82 char *t; 83 int b; 84 85 for (b = 1; b <= bytes; b++) { 86 if (size < sizeof "255.") 87 return (0); 88 t = dst; 89 dst += SPRINTF((dst, "%u", *src++)); 90 if (b != bytes) { 91 *dst++ = '.'; 92 *dst = '\0'; 93 } 94 size -= (size_t)(dst - t); 95 } 96 return (dst - odst); 97 } 98 99 /*% 100 * static char * 101 * inet_cidr_ntop_ipv4(src, bits, dst, size) 102 * convert IPv4 network address from network to presentation format. 103 * "src"'s size is determined from its "af". 104 * return: 105 * pointer to dst, or NULL if an error occurred (check errno). 106 * note: 107 * network byte order assumed. this means 192.5.5.240/28 has 108 * 0b11110000 in its fourth octet. 109 * author: 110 * Paul Vixie (ISC), October 1998 111 */ 112 static char * 113 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) { 114 char *odst = dst; 115 size_t len = 4; 116 size_t b; 117 size_t bytes; 118 119 if ((bits < -1) || (bits > 32)) { 120 errno = EINVAL; 121 return (NULL); 122 } 123 124 /* Find number of significant bytes in address. */ 125 if (bits == -1) 126 len = 4; 127 else 128 for (len = 1, b = 1 ; b < 4U; b++) 129 if (*(src + b)) 130 len = b + 1; 131 132 /* Format whole octets plus nonzero trailing octets. */ 133 bytes = (((bits <= 0) ? 1 : bits) + 7) / 8; 134 if (len > bytes) 135 bytes = len; 136 b = decoct(src, bytes, dst, size); 137 if (b == 0U) 138 goto emsgsize; 139 dst += b; 140 size -= b; 141 142 if (bits != -1) { 143 /* Format CIDR /width. */ 144 if (size < sizeof "/32") 145 goto emsgsize; 146 dst += SPRINTF((dst, "/%u", bits)); 147 } 148 149 return (odst); 150 151 emsgsize: 152 errno = EMSGSIZE; 153 return (NULL); 154 } 155 156 static char * 157 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) { 158 /* 159 * Note that int32_t and int16_t need only be "at least" large enough 160 * to contain a value of the specified size. On some systems, like 161 * Crays, there is no such thing as an integer variable with 16 bits. 162 * Keep this in mind if you think this function should have been coded 163 * to use pointer overlays. All the world's not a VAX. 164 */ 165 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"]; 166 char *tp; 167 struct { int base, len; } best, cur; 168 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 169 int i; 170 171 if ((bits < -1) || (bits > 128)) { 172 errno = EINVAL; 173 return (NULL); 174 } 175 176 /* 177 * Preprocess: 178 * Copy the input (bytewise) array into a wordwise array. 179 * Find the longest run of 0x00's in src[] for :: shorthanding. 180 */ 181 memset(words, '\0', sizeof words); 182 for (i = 0; i < NS_IN6ADDRSZ; i++) 183 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 184 best.base = -1; 185 best.len = 0; 186 cur.base = -1; 187 cur.len = 0; 188 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 189 if (words[i] == 0) { 190 if (cur.base == -1) 191 cur.base = i, cur.len = 1; 192 else 193 cur.len++; 194 } else { 195 if (cur.base != -1) { 196 if (best.base == -1 || cur.len > best.len) 197 best = cur; 198 cur.base = -1; 199 } 200 } 201 } 202 if (cur.base != -1) { 203 if (best.base == -1 || cur.len > best.len) 204 best = cur; 205 } 206 if (best.base != -1 && best.len < 2) 207 best.base = -1; 208 209 /* 210 * Format the result. 211 */ 212 tp = tmp; 213 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 214 /* Are we inside the best run of 0x00's? */ 215 if (best.base != -1 && i >= best.base && 216 i < (best.base + best.len)) { 217 if (i == best.base) 218 *tp++ = ':'; 219 continue; 220 } 221 /* Are we following an initial run of 0x00s or any real hex? */ 222 if (i != 0) 223 *tp++ = ':'; 224 /* Is this address an encapsulated IPv4? */ 225 if (i == 6 && best.base == 0 && (best.len == 6 || 226 (best.len == 7 && words[7] != 0x0001) || 227 (best.len == 5 && words[5] == 0xffff))) { 228 int n; 229 230 if (src[15] || bits == -1 || bits > 120) 231 n = 4; 232 else if (src[14] || bits > 112) 233 n = 3; 234 else 235 n = 2; 236 n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp)); 237 if (n == 0) { 238 errno = EMSGSIZE; 239 return (NULL); 240 } 241 tp += strlen(tp); 242 break; 243 } 244 tp += SPRINTF((tp, "%x", words[i])); 245 } 246 247 /* Was it a trailing run of 0x00's? */ 248 if (best.base != -1 && (best.base + best.len) == 249 (NS_IN6ADDRSZ / NS_INT16SZ)) 250 *tp++ = ':'; 251 *tp = '\0'; 252 253 if (bits != -1) 254 tp += SPRINTF((tp, "/%u", bits)); 255 256 /* 257 * Check for overflow, copy, and we're done. 258 */ 259 if ((size_t)(tp - tmp) > size) { 260 errno = EMSGSIZE; 261 return (NULL); 262 } 263 strcpy(dst, tmp); 264 return (dst); 265 } 266 267 /*! \file */ 268