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 #ifdef HAVE_SYS_SOCKET_H 27 #include <sys/socket.h> 28 #endif 29 #ifdef HAVE_NETINET_IN_H 30 #include <netinet/in.h> 31 #endif 32 #include <string.h> 33 #include <errno.h> 34 #include <stdio.h> 35 36 #ifndef IN6ADDRSZ 37 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */ 38 #endif 39 40 #ifndef INT16SZ 41 #define INT16SZ 2 /* for systems without 16-bit ints */ 42 #endif 43 44 /* 45 * WARNING: Don't even consider trying to compile this on a system where 46 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 47 */ 48 49 static const char *inet_ntop4(const u_char *src, char *dst, size_t size); 50 static const char *inet_ntop6(const u_char *src, char *dst, size_t size); 51 52 /* char * 53 * inet_ntop(af, src, dst, size) 54 * convert a network format address to presentation format. 55 * return: 56 * pointer to presentation format address (`dst'), or NULL (see errno). 57 * author: 58 * Paul Vixie, 1996. 59 */ 60 const char * 61 inet_ntop(int af, const void *src, char *dst, size_t size) 62 { 63 switch (af) { 64 case AF_INET: 65 return (inet_ntop4(src, dst, size)); 66 case AF_INET6: 67 return (inet_ntop6(src, dst, size)); 68 default: 69 #ifdef EAFNOSUPPORT 70 errno = EAFNOSUPPORT; 71 #else 72 errno = ENOSYS; 73 #endif 74 return (NULL); 75 } 76 /* NOTREACHED */ 77 } 78 79 /* const char * 80 * inet_ntop4(src, dst, size) 81 * format an IPv4 address, more or less like inet_ntoa() 82 * return: 83 * `dst' (as a const) 84 * notes: 85 * (1) uses no statics 86 * (2) takes a u_char* not an in_addr as input 87 * author: 88 * Paul Vixie, 1996. 89 */ 90 static const char * 91 inet_ntop4(const u_char *src, char *dst, size_t size) 92 { 93 static const char fmt[] = "%u.%u.%u.%u"; 94 char tmp[sizeof "255.255.255.255"]; 95 int l; 96 97 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]); 98 if (l <= 0 || l >= (int)size) { 99 errno = ENOSPC; 100 return (NULL); 101 } 102 strlcpy(dst, tmp, size); 103 return (dst); 104 } 105 106 /* const char * 107 * inet_ntop6(src, dst, size) 108 * convert IPv6 binary address into presentation (printable) format 109 * author: 110 * Paul Vixie, 1996. 111 */ 112 static const char * 113 inet_ntop6(const u_char *src, char *dst, size_t size) 114 { 115 /* 116 * Note that int32_t and int16_t need only be "at least" large enough 117 * to contain a value of the specified size. On some systems, like 118 * Crays, there is no such thing as an integer variable with 16 bits. 119 * Keep this in mind if you think this function should have been coded 120 * to use pointer overlays. All the world's not a VAX. 121 */ 122 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"]; 123 char *tp, *ep; 124 struct { int base, len; } best, cur; 125 u_int words[IN6ADDRSZ / INT16SZ]; 126 int i; 127 int advance; 128 129 /* 130 * Preprocess: 131 * Copy the input (bytewise) array into a wordwise array. 132 * Find the longest run of 0x00's in src[] for :: shorthanding. 133 */ 134 memset(words, '\0', sizeof words); 135 for (i = 0; i < IN6ADDRSZ; i++) 136 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 137 best.base = -1; 138 best.len = 0; 139 cur.base = -1; 140 cur.len = 0; 141 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) { 142 if (words[i] == 0) { 143 if (cur.base == -1) 144 cur.base = i, cur.len = 1; 145 else 146 cur.len++; 147 } else { 148 if (cur.base != -1) { 149 if (best.base == -1 || cur.len > best.len) 150 best = cur; 151 cur.base = -1; 152 } 153 } 154 } 155 if (cur.base != -1) { 156 if (best.base == -1 || cur.len > best.len) 157 best = cur; 158 } 159 if (best.base != -1 && best.len < 2) 160 best.base = -1; 161 162 /* 163 * Format the result. 164 */ 165 tp = tmp; 166 ep = tmp + sizeof(tmp); 167 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) { 168 /* Are we inside the best run of 0x00's? */ 169 if (best.base != -1 && i >= best.base && 170 i < (best.base + best.len)) { 171 if (i == best.base) { 172 if (tp + 1 >= ep) 173 return (NULL); 174 *tp++ = ':'; 175 } 176 continue; 177 } 178 /* Are we following an initial run of 0x00s or any real hex? */ 179 if (i != 0) { 180 if (tp + 1 >= ep) 181 return (NULL); 182 *tp++ = ':'; 183 } 184 /* Is this address an encapsulated IPv4? */ 185 if (i == 6 && best.base == 0 && 186 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { 187 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp))) 188 return (NULL); 189 tp += strlen(tp); 190 break; 191 } 192 advance = snprintf(tp, ep - tp, "%x", words[i]); 193 if (advance <= 0 || advance >= ep - tp) 194 return (NULL); 195 tp += advance; 196 } 197 /* Was it a trailing run of 0x00's? */ 198 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) { 199 if (tp + 1 >= ep) 200 return (NULL); 201 *tp++ = ':'; 202 } 203 if (tp + 1 >= ep) 204 return (NULL); 205 *tp++ = '\0'; 206 207 /* 208 * Check for overflow, copy, and we're done. 209 */ 210 if ((size_t)(tp - tmp) > size) { 211 errno = ENOSPC; 212 return (NULL); 213 } 214 strlcpy(dst, tmp, size); 215 return (dst); 216 } 217 218 #endif /* !HAVE_INET_NTOP */ 219