1/* From openssh 4.3p2 compat/inet_ntop.c */ 2/* Copyright (c) 1996 by 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 DISCLAIMS 9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 15 * SOFTWARE. 16 */ 17 18/* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */ 19 20#include <config.h> 21 22#ifndef HAVE_INET_NTOP 23 24#include <sys/param.h> 25#include <sys/types.h> 26#include <sys/socket.h> 27#include <netinet/in.h> 28#include <string.h> 29#include <errno.h> 30#include <stdio.h> 31 32#ifndef IN6ADDRSZ 33#define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 34#endif 35 36#ifndef INT16SZ 37#define INT16SZ 2 /* for systems without 16-bit ints */ 38#endif 39 40/* 41 * WARNING: Don't even consider trying to compile this on a system where 42 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 43 */ 44 45static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 46static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 47 48/* char * 49 * inet_ntop(af, src, dst, size) 50 * convert a network format address to presentation format. 51 * return: 52 * pointer to presentation format address (`dst'), or NULL (see errno). 53 * author: 54 * Paul Vixie, 1996. 55 */ 56const char * 57inet_ntop(int af, const void *src, char *dst, size_t size) 58{ 59 switch (af) { 60 case AF_INET: 61 return (inet_ntop4(src, dst, size)); 62 case AF_INET6: 63 return (inet_ntop6(src, dst, size)); 64 default: 65 errno = EAFNOSUPPORT; 66 return (NULL); 67 } 68 /* NOTREACHED */ 69} 70 71/* const char * 72 * inet_ntop4(src, dst, size) 73 * format an IPv4 address, more or less like inet_ntoa() 74 * return: 75 * `dst' (as a const) 76 * notes: 77 * (1) uses no statics 78 * (2) takes a u_char* not an in_addr as input 79 * author: 80 * Paul Vixie, 1996. 81 */ 82static const char * 83inet_ntop4(const u_char *src, char *dst, size_t size) 84{ 85 static const char fmt[] = "%u.%u.%u.%u"; 86 char tmp[sizeof "255.255.255.255"]; 87 int l; 88 89 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]); 90 if (l <= 0 || l >= (int)size) { 91 errno = ENOSPC; 92 return (NULL); 93 } 94 strlcpy(dst, tmp, size); 95 return (dst); 96} 97 98/* const char * 99 * inet_ntop6(src, dst, size) 100 * convert IPv6 binary address into presentation (printable) format 101 * author: 102 * Paul Vixie, 1996. 103 */ 104static const char * 105inet_ntop6(const u_char *src, char *dst, size_t size) 106{ 107 /* 108 * Note that int32_t and int16_t need only be "at least" large enough 109 * to contain a value of the specified size. On some systems, like 110 * Crays, there is no such thing as an integer variable with 16 bits. 111 * Keep this in mind if you think this function should have been coded 112 * to use pointer overlays. All the world's not a VAX. 113 */ 114 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"]; 115 char *tp, *ep; 116 struct { int base, len; } best, cur; 117 u_int words[IN6ADDRSZ / INT16SZ]; 118 int i; 119 int advance; 120 121 /* 122 * Preprocess: 123 * Copy the input (bytewise) array into a wordwise array. 124 * Find the longest run of 0x00's in src[] for :: shorthanding. 125 */ 126 memset(words, '\0', sizeof words); 127 for (i = 0; i < IN6ADDRSZ; i++) 128 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 129 best.base = -1; 130 cur.base = -1; 131 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 132 if (words[i] == 0) { 133 if (cur.base == -1) 134 cur.base = i, cur.len = 1; 135 else 136 cur.len++; 137 } else { 138 if (cur.base != -1) { 139 if (best.base == -1 || cur.len > best.len) 140 best = cur; 141 cur.base = -1; 142 } 143 } 144 } 145 if (cur.base != -1) { 146 if (best.base == -1 || cur.len > best.len) 147 best = cur; 148 } 149 if (best.base != -1 && best.len < 2) 150 best.base = -1; 151 152 /* 153 * Format the result. 154 */ 155 tp = tmp; 156 ep = tmp + sizeof(tmp); 157 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) { 158 /* Are we inside the best run of 0x00's? */ 159 if (best.base != -1 && i >= best.base && 160 i < (best.base + best.len)) { 161 if (i == best.base) { 162 if (tp + 1 >= ep) 163 return (NULL); 164 *tp++ = ':'; 165 } 166 continue; 167 } 168 /* Are we following an initial run of 0x00s or any real hex? */ 169 if (i != 0) { 170 if (tp + 1 >= ep) 171 return (NULL); 172 *tp++ = ':'; 173 } 174 /* Is this address an encapsulated IPv4? */ 175 if (i == 6 && best.base == 0 && 176 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 177 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp))) 178 return (NULL); 179 tp += strlen(tp); 180 break; 181 } 182 advance = snprintf(tp, ep - tp, "%x", words[i]); 183 if (advance <= 0 || advance >= ep - tp) 184 return (NULL); 185 tp += advance; 186 } 187 /* Was it a trailing run of 0x00's? */ 188 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) { 189 if (tp + 1 >= ep) 190 return (NULL); 191 *tp++ = ':'; 192 } 193 if (tp + 1 >= ep) 194 return (NULL); 195 *tp++ = '\0'; 196 197 /* 198 * Check for overflow, copy, and we're done. 199 */ 200 if ((size_t)(tp - tmp) > size) { 201 errno = ENOSPC; 202 return (NULL); 203 } 204 strlcpy(dst, tmp, size); 205 return (dst); 206} 207 208#endif /* !HAVE_INET_NTOP */ 209