| 1 | /* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form |
| 2 | |
| 3 | Copyright (C) 2005-2006, 2008-2020 Free Software Foundation, Inc. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation; either version 3, or (at your option) |
| 8 | any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | /* |
| 19 | * Copyright (c) 1996-1999 by Internet Software Consortium. |
| 20 | * |
| 21 | * Permission to use, copy, modify, and distribute this software for any |
| 22 | * purpose with or without fee is hereby granted, provided that the above |
| 23 | * copyright notice and this permission notice appear in all copies. |
| 24 | * |
| 25 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
| 26 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
| 27 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
| 28 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
| 29 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| 30 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
| 31 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
| 32 | * SOFTWARE. |
| 33 | */ |
| 34 | |
| 35 | #include <config.h> |
| 36 | |
| 37 | /* Specification. */ |
| 38 | #include <arpa/inet.h> |
| 39 | |
| 40 | /* Use this to suppress gcc's "...may be used before initialized" warnings. |
| 41 | Beware: The Code argument must not contain commas. */ |
| 42 | #ifndef IF_LINT |
| 43 | # if defined GCC_LINT || defined lint |
| 44 | # define IF_LINT(Code) Code |
| 45 | # else |
| 46 | # define IF_LINT(Code) /* empty */ |
| 47 | # endif |
| 48 | #endif |
| 49 | |
| 50 | #if HAVE_DECL_INET_NTOP |
| 51 | |
| 52 | # undef inet_ntop |
| 53 | |
| 54 | const char * |
| 55 | rpl_inet_ntop (int af, const void *restrict src, |
| 56 | char *restrict dst, socklen_t cnt) |
| 57 | { |
| 58 | return inet_ntop (af, src, dst, cnt); |
| 59 | } |
| 60 | |
| 61 | #else |
| 62 | |
| 63 | # include <stdio.h> |
| 64 | # include <string.h> |
| 65 | # include <errno.h> |
| 66 | |
| 67 | # define NS_IN6ADDRSZ 16 |
| 68 | # define NS_INT16SZ 2 |
| 69 | |
| 70 | /* |
| 71 | * WARNING: Don't even consider trying to compile this on a system where |
| 72 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. |
| 73 | */ |
| 74 | typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1]; |
| 75 | |
| 76 | static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size); |
| 77 | # if HAVE_IPV6 |
| 78 | static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size); |
| 79 | # endif |
| 80 | |
| 81 | |
| 82 | /* char * |
| 83 | * inet_ntop(af, src, dst, size) |
| 84 | * convert a network format address to presentation format. |
| 85 | * return: |
| 86 | * pointer to presentation format address ('dst'), or NULL (see errno). |
| 87 | * author: |
| 88 | * Paul Vixie, 1996. |
| 89 | */ |
| 90 | const char * |
| 91 | inet_ntop (int af, const void *restrict src, |
| 92 | char *restrict dst, socklen_t cnt) |
| 93 | { |
| 94 | switch (af) |
| 95 | { |
| 96 | # if HAVE_IPV4 |
| 97 | case AF_INET: |
| 98 | return (inet_ntop4 (src, dst, cnt)); |
| 99 | # endif |
| 100 | |
| 101 | # if HAVE_IPV6 |
| 102 | case AF_INET6: |
| 103 | return (inet_ntop6 (src, dst, cnt)); |
| 104 | # endif |
| 105 | |
| 106 | default: |
| 107 | errno = EAFNOSUPPORT; |
| 108 | return (NULL); |
| 109 | } |
| 110 | /* NOTREACHED */ |
| 111 | } |
| 112 | |
| 113 | /* const char * |
| 114 | * inet_ntop4(src, dst, size) |
| 115 | * format an IPv4 address |
| 116 | * return: |
| 117 | * 'dst' (as a const) |
| 118 | * notes: |
| 119 | * (1) uses no statics |
| 120 | * (2) takes a u_char* not an in_addr as input |
| 121 | * author: |
| 122 | * Paul Vixie, 1996. |
| 123 | */ |
| 124 | static const char * |
| 125 | inet_ntop4 (const unsigned char *src, char *dst, socklen_t size) |
| 126 | { |
| 127 | char tmp[sizeof "255.255.255.255"]; |
| 128 | int len; |
| 129 | |
| 130 | len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]); |
| 131 | if (len < 0) |
| 132 | return NULL; |
| 133 | |
| 134 | if (len > size) |
| 135 | { |
| 136 | errno = ENOSPC; |
| 137 | return NULL; |
| 138 | } |
| 139 | |
| 140 | return strcpy (dst, tmp); |
| 141 | } |
| 142 | |
| 143 | # if HAVE_IPV6 |
| 144 | |
| 145 | /* const char * |
| 146 | * inet_ntop6(src, dst, size) |
| 147 | * convert IPv6 binary address into presentation (printable) format |
| 148 | * author: |
| 149 | * Paul Vixie, 1996. |
| 150 | */ |
| 151 | static const char * |
| 152 | inet_ntop6 (const unsigned char *src, char *dst, socklen_t size) |
| 153 | { |
| 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"], *tp; |
| 162 | struct |
| 163 | { |
| 164 | int base, len; |
| 165 | } best, cur; |
| 166 | unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; |
| 167 | int i; |
| 168 | |
| 169 | /* |
| 170 | * Preprocess: |
| 171 | * Copy the input (bytewise) array into a wordwise array. |
| 172 | * Find the longest run of 0x00's in src[] for :: shorthanding. |
| 173 | */ |
| 174 | memset (words, '\0', sizeof words); |
| 175 | for (i = 0; i < NS_IN6ADDRSZ; i += 2) |
| 176 | words[i / 2] = (src[i] << 8) | src[i + 1]; |
| 177 | best.base = -1; |
| 178 | cur.base = -1; |
| 179 | IF_LINT(best.len = 0); |
| 180 | IF_LINT(cur.len = 0); |
| 181 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) |
| 182 | { |
| 183 | if (words[i] == 0) |
| 184 | { |
| 185 | if (cur.base == -1) |
| 186 | cur.base = i, cur.len = 1; |
| 187 | else |
| 188 | cur.len++; |
| 189 | } |
| 190 | else |
| 191 | { |
| 192 | if (cur.base != -1) |
| 193 | { |
| 194 | if (best.base == -1 || cur.len > best.len) |
| 195 | best = cur; |
| 196 | cur.base = -1; |
| 197 | } |
| 198 | } |
| 199 | } |
| 200 | if (cur.base != -1) |
| 201 | { |
| 202 | if (best.base == -1 || cur.len > best.len) |
| 203 | best = cur; |
| 204 | } |
| 205 | if (best.base != -1 && best.len < 2) |
| 206 | best.base = -1; |
| 207 | |
| 208 | /* |
| 209 | * Format the result. |
| 210 | */ |
| 211 | tp = tmp; |
| 212 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) |
| 213 | { |
| 214 | /* Are we inside the best run of 0x00's? */ |
| 215 | if (best.base != -1 && i >= best.base && i < (best.base + best.len)) |
| 216 | { |
| 217 | if (i == best.base) |
| 218 | *tp++ = ':'; |
| 219 | continue; |
| 220 | } |
| 221 | /* Are we following an initial run of 0x00s or any real hex? */ |
| 222 | if (i != 0) |
| 223 | *tp++ = ':'; |
| 224 | /* Is this address an encapsulated IPv4? */ |
| 225 | if (i == 6 && best.base == 0 && |
| 226 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) |
| 227 | { |
| 228 | if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp))) |
| 229 | return (NULL); |
| 230 | tp += strlen (tp); |
| 231 | break; |
| 232 | } |
| 233 | { |
| 234 | int len = sprintf (tp, "%x", words[i]); |
| 235 | if (len < 0) |
| 236 | return NULL; |
| 237 | tp += len; |
| 238 | } |
| 239 | } |
| 240 | /* Was it a trailing run of 0x00's? */ |
| 241 | if (best.base != -1 && (best.base + best.len) == |
| 242 | (NS_IN6ADDRSZ / NS_INT16SZ)) |
| 243 | *tp++ = ':'; |
| 244 | *tp++ = '\0'; |
| 245 | |
| 246 | /* |
| 247 | * Check for overflow, copy, and we're done. |
| 248 | */ |
| 249 | if ((socklen_t) (tp - tmp) > size) |
| 250 | { |
| 251 | errno = ENOSPC; |
| 252 | return NULL; |
| 253 | } |
| 254 | |
| 255 | return strcpy (dst, tmp); |
| 256 | } |
| 257 | |
| 258 | # endif |
| 259 | |
| 260 | #endif |