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 #include "port_before.h" 21 22 #include <sys/types.h> 23 #include <sys/socket.h> 24 #include <netinet/in.h> 25 #include <arpa/nameser.h> 26 #include <arpa/inet.h> 27 28 #include <errno.h> 29 #include <stdio.h> 30 #include <string.h> 31 #include <stdlib.h> 32 33 #include "port_after.h" 34 35 #ifdef SPRINTF_CHAR 36 # define SPRINTF(x) strlen(sprintf/**/x) 37 #else 38 # define SPRINTF(x) ((size_t)sprintf x) 39 #endif 40 41 static char * 42 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size); 43 static char * 44 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size); 45 46 /*% 47 * char * 48 * inet_cidr_ntop(af, src, bits, dst, size) 49 * convert network address from network to presentation format. 50 * "src"'s size is determined from its "af". 51 * return: 52 * pointer to dst, or NULL if an error occurred (check errno). 53 * note: 54 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network 55 * as called for by inet_net_ntop() but it can be a host address with 56 * an included netmask. 57 * author: 58 * Paul Vixie (ISC), October 1998 59 */ 60 char * 61 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) { 62 switch (af) { 63 case AF_INET: 64 return (inet_cidr_ntop_ipv4(src, bits, dst, size)); 65 case AF_INET6: 66 return (inet_cidr_ntop_ipv6(src, bits, dst, size)); 67 default: 68 errno = EAFNOSUPPORT; 69 return (NULL); 70 } 71 } 72 73 static int 74 decoct(const u_char *src, int bytes, char *dst, size_t size) { 75 char *odst = dst; 76 char *t; 77 int b; 78 79 for (b = 1; b <= bytes; b++) { 80 if (size < sizeof "255.") 81 return (0); 82 t = dst; 83 dst += SPRINTF((dst, "%u", *src++)); 84 if (b != bytes) { 85 *dst++ = '.'; 86 *dst = '\0'; 87 } 88 size -= (size_t)(dst - t); 89 } 90 return (dst - odst); 91 } 92 93 /*% 94 * static char * 95 * inet_cidr_ntop_ipv4(src, bits, dst, size) 96 * convert IPv4 network address from network to presentation format. 97 * "src"'s size is determined from its "af". 98 * return: 99 * pointer to dst, or NULL if an error occurred (check errno). 100 * note: 101 * network byte order assumed. this means 192.5.5.240/28 has 102 * 0b11110000 in its fourth octet. 103 * author: 104 * Paul Vixie (ISC), October 1998 105 */ 106 static char * 107 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) { 108 char *odst = dst; 109 size_t len = 4; 110 size_t b; 111 size_t bytes; 112 113 if ((bits < -1) || (bits > 32)) { 114 errno = EINVAL; 115 return (NULL); 116 } 117 118 /* Find number of significant bytes in address. */ 119 if (bits == -1) 120 len = 4; 121 else 122 for (len = 1, b = 1 ; b < 4U; b++) 123 if (*(src + b)) 124 len = b + 1; 125 126 /* Format whole octets plus nonzero trailing octets. */ 127 bytes = (((bits <= 0) ? 1 : bits) + 7) / 8; 128 if (len > bytes) 129 bytes = len; 130 b = decoct(src, bytes, dst, size); 131 if (b == 0U) 132 goto emsgsize; 133 dst += b; 134 size -= b; 135 136 if (bits != -1) { 137 /* Format CIDR /width. */ 138 if (size < sizeof "/32") 139 goto emsgsize; 140 dst += SPRINTF((dst, "/%u", bits)); 141 } 142 143 return (odst); 144 145 emsgsize: 146 errno = EMSGSIZE; 147 return (NULL); 148 } 149 150 static char * 151 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) { 152 /* 153 * Note that int32_t and int16_t need only be "at least" large enough 154 * to contain a value of the specified size. On some systems, like 155 * Crays, there is no such thing as an integer variable with 16 bits. 156 * Keep this in mind if you think this function should have been coded 157 * to use pointer overlays. All the world's not a VAX. 158 */ 159 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"]; 160 char *tp; 161 struct { int base, len; } best, cur; 162 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 163 int i; 164 165 if ((bits < -1) || (bits > 128)) { 166 errno = EINVAL; 167 return (NULL); 168 } 169 170 /* 171 * Preprocess: 172 * Copy the input (bytewise) array into a wordwise array. 173 * Find the longest run of 0x00's in src[] for :: shorthanding. 174 */ 175 memset(words, '\0', sizeof words); 176 for (i = 0; i < NS_IN6ADDRSZ; i++) 177 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 178 best.base = -1; 179 best.len = 0; 180 cur.base = -1; 181 cur.len = 0; 182 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 183 if (words[i] == 0) { 184 if (cur.base == -1) 185 cur.base = i, cur.len = 1; 186 else 187 cur.len++; 188 } else { 189 if (cur.base != -1) { 190 if (best.base == -1 || cur.len > best.len) 191 best = cur; 192 cur.base = -1; 193 } 194 } 195 } 196 if (cur.base != -1) { 197 if (best.base == -1 || cur.len > best.len) 198 best = cur; 199 } 200 if (best.base != -1 && best.len < 2) 201 best.base = -1; 202 203 /* 204 * Format the result. 205 */ 206 tp = tmp; 207 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 208 /* Are we inside the best run of 0x00's? */ 209 if (best.base != -1 && i >= best.base && 210 i < (best.base + best.len)) { 211 if (i == best.base) 212 *tp++ = ':'; 213 continue; 214 } 215 /* Are we following an initial run of 0x00s or any real hex? */ 216 if (i != 0) 217 *tp++ = ':'; 218 /* Is this address an encapsulated IPv4? */ 219 if (i == 6 && best.base == 0 && (best.len == 6 || 220 (best.len == 7 && words[7] != 0x0001) || 221 (best.len == 5 && words[5] == 0xffff))) { 222 int n; 223 224 if (src[15] || bits == -1 || bits > 120) 225 n = 4; 226 else if (src[14] || bits > 112) 227 n = 3; 228 else 229 n = 2; 230 n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp)); 231 if (n == 0) { 232 errno = EMSGSIZE; 233 return (NULL); 234 } 235 tp += strlen(tp); 236 break; 237 } 238 tp += SPRINTF((tp, "%x", words[i])); 239 } 240 241 /* Was it a trailing run of 0x00's? */ 242 if (best.base != -1 && (best.base + best.len) == 243 (NS_IN6ADDRSZ / NS_INT16SZ)) 244 *tp++ = ':'; 245 *tp = '\0'; 246 247 if (bits != -1) 248 tp += SPRINTF((tp, "/%u", bits)); 249 250 /* 251 * Check for overflow, copy, and we're done. 252 */ 253 if ((size_t)(tp - tmp) > size) { 254 errno = EMSGSIZE; 255 return (NULL); 256 } 257 strcpy(dst, tmp); 258 return (dst); 259 } 260 261 /*! \file */ 262