1 /*- 2 * SPDX-License-Identifier: ISC 3 * 4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (c) 1996,1999 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_net_ntop.c,v 1.5 2006/06/20 02:50:14 marka Exp $"; 22 #endif 23 #include "port_before.h" 24 25 #include <sys/types.h> 26 #include <sys/socket.h> 27 #include <netinet/in.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 * inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, 44 size_t size); 45 static char * inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, 46 size_t size); 47 48 /*% 49 * char * 50 * inet_net_ntop(af, src, bits, dst, size) 51 * convert network number from network to presentation format. 52 * generates CIDR style result always. 53 * return: 54 * pointer to dst, or NULL if an error occurred (check errno). 55 * author: 56 * Paul Vixie (ISC), July 1996 57 */ 58 char * 59 inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size) 60 { 61 switch (af) { 62 case AF_INET: 63 return (inet_net_ntop_ipv4(src, bits, dst, size)); 64 case AF_INET6: 65 return (inet_net_ntop_ipv6(src, bits, dst, size)); 66 default: 67 errno = EAFNOSUPPORT; 68 return (NULL); 69 } 70 } 71 72 /*% 73 * static char * 74 * inet_net_ntop_ipv4(src, bits, dst, size) 75 * convert IPv4 network number from network to presentation format. 76 * generates CIDR style result always. 77 * return: 78 * pointer to dst, or NULL if an error occurred (check errno). 79 * note: 80 * network byte order assumed. this means 192.5.5.240/28 has 81 * 0b11110000 in its fourth octet. 82 * author: 83 * Paul Vixie (ISC), July 1996 84 */ 85 static char * 86 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) 87 { 88 char *odst = dst; 89 char *t; 90 u_int m; 91 int b; 92 93 if (bits < 0 || bits > 32) { 94 errno = EINVAL; 95 return (NULL); 96 } 97 98 if (bits == 0) { 99 if (size < sizeof "0") 100 goto emsgsize; 101 *dst++ = '0'; 102 size--; 103 *dst = '\0'; 104 } 105 106 /* Format whole octets. */ 107 for (b = bits / 8; b > 0; b--) { 108 if (size <= sizeof "255.") 109 goto emsgsize; 110 t = dst; 111 dst += SPRINTF((dst, "%u", *src++)); 112 if (b > 1) { 113 *dst++ = '.'; 114 *dst = '\0'; 115 } 116 size -= (size_t)(dst - t); 117 } 118 119 /* Format partial octet. */ 120 b = bits % 8; 121 if (b > 0) { 122 if (size <= sizeof ".255") 123 goto emsgsize; 124 t = dst; 125 if (dst != odst) 126 *dst++ = '.'; 127 m = ((1 << b) - 1) << (8 - b); 128 dst += SPRINTF((dst, "%u", *src & m)); 129 size -= (size_t)(dst - t); 130 } 131 132 /* Format CIDR /width. */ 133 if (size <= sizeof "/32") 134 goto emsgsize; 135 dst += SPRINTF((dst, "/%u", bits)); 136 return (odst); 137 138 emsgsize: 139 errno = EMSGSIZE; 140 return (NULL); 141 } 142 143 /*% 144 * static char * 145 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size) 146 * convert IPv6 network number from network to presentation format. 147 * generates CIDR style result always. Picks the shortest representation 148 * unless the IP is really IPv4. 149 * always prints specified number of bits (bits). 150 * return: 151 * pointer to dst, or NULL if an error occurred (check errno). 152 * note: 153 * network byte order assumed. this means 192.5.5.240/28 has 154 * 0b11110000 in its fourth octet. 155 * author: 156 * Vadim Kogan (UCB), June 2001 157 * Original version (IPv4) by Paul Vixie (ISC), July 1996 158 */ 159 160 static char * 161 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) { 162 u_int m; 163 int b; 164 int p; 165 int zero_s, zero_l, tmp_zero_s, tmp_zero_l; 166 int i; 167 int is_ipv4 = 0; 168 unsigned char inbuf[16]; 169 char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")]; 170 char *cp; 171 int words; 172 u_char *s; 173 174 if (bits < 0 || bits > 128) { 175 errno = EINVAL; 176 return (NULL); 177 } 178 179 cp = outbuf; 180 181 if (bits == 0) { 182 *cp++ = ':'; 183 *cp++ = ':'; 184 *cp = '\0'; 185 } else { 186 /* Copy src to private buffer. Zero host part. */ 187 p = (bits + 7) / 8; 188 memcpy(inbuf, src, p); 189 memset(inbuf + p, 0, 16 - p); 190 b = bits % 8; 191 if (b != 0) { 192 m = ~0 << (8 - b); 193 inbuf[p-1] &= m; 194 } 195 196 s = inbuf; 197 198 /* how many words need to be displayed in output */ 199 words = (bits + 15) / 16; 200 if (words == 1) 201 words = 2; 202 203 /* Find the longest substring of zero's */ 204 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0; 205 for (i = 0; i < (words * 2); i += 2) { 206 if ((s[i] | s[i+1]) == 0) { 207 if (tmp_zero_l == 0) 208 tmp_zero_s = i / 2; 209 tmp_zero_l++; 210 } else { 211 if (tmp_zero_l && zero_l < tmp_zero_l) { 212 zero_s = tmp_zero_s; 213 zero_l = tmp_zero_l; 214 tmp_zero_l = 0; 215 } 216 } 217 } 218 219 if (tmp_zero_l && zero_l < tmp_zero_l) { 220 zero_s = tmp_zero_s; 221 zero_l = tmp_zero_l; 222 } 223 224 if (zero_l != words && zero_s == 0 && ((zero_l == 6) || 225 ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) || 226 ((zero_l == 7 && s[14] != 0 && s[15] != 1))))) 227 is_ipv4 = 1; 228 229 /* Format whole words. */ 230 for (p = 0; p < words; p++) { 231 if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) { 232 /* Time to skip some zeros */ 233 if (p == zero_s) 234 *cp++ = ':'; 235 if (p == words - 1) 236 *cp++ = ':'; 237 s++; 238 s++; 239 continue; 240 } 241 242 if (is_ipv4 && p > 5 ) { 243 *cp++ = (p == 6) ? ':' : '.'; 244 cp += SPRINTF((cp, "%u", *s++)); 245 /* we can potentially drop the last octet */ 246 if (p != 7 || bits > 120) { 247 *cp++ = '.'; 248 cp += SPRINTF((cp, "%u", *s++)); 249 } 250 } else { 251 if (cp != outbuf) 252 *cp++ = ':'; 253 cp += SPRINTF((cp, "%x", *s * 256 + s[1])); 254 s += 2; 255 } 256 } 257 } 258 /* Format CIDR /width. */ 259 sprintf(cp, "/%u", bits); 260 if (strlen(outbuf) + 1 > size) 261 goto emsgsize; 262 strcpy(dst, outbuf); 263 264 return (dst); 265 266 emsgsize: 267 errno = EMSGSIZE; 268 return (NULL); 269 } 270 271 /* 272 * Weak aliases for applications that use certain private entry points, 273 * and fail to include <arpa/inet.h>. 274 */ 275 #undef inet_net_ntop 276 __weak_reference(__inet_net_ntop, inet_net_ntop); 277 278 /*! \file */ 279