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