2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1998,1999 by Internet Software Consortium.
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.
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.
17 * $Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp $
20 #include "port_before.h"
22 #include <sys/types.h>
23 #include <sys/socket.h>
24 #include <netinet/in.h>
25 #include <arpa/nameser.h>
26 #include <arpa/inet.h>
33 #include "port_after.h"
36 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
38 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
42 * inet_cidr_ntop(af, src, bits, dst, size)
43 * convert network address from network to presentation format.
44 * "src"'s size is determined from its "af".
46 * pointer to dst, or NULL if an error occurred (check errno).
48 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network
49 * as called for by inet_net_ntop() but it can be a host address with
50 * an included netmask.
52 * Paul Vixie (ISC), October 1998
55 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
58 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
60 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
68 decoct(const u_char *src, int bytes, char *dst, size_t size) {
73 for (b = 1; b <= bytes; b++) {
74 if (size < sizeof "255.")
77 dst += sprintf(dst, "%u", *src++);
82 size -= (size_t)(dst - t);
89 * inet_cidr_ntop_ipv4(src, bits, dst, size)
90 * convert IPv4 network address from network to presentation format.
91 * "src"'s size is determined from its "af".
93 * pointer to dst, or NULL if an error occurred (check errno).
95 * network byte order assumed. this means 192.5.5.240/28 has
96 * 0b11110000 in its fourth octet.
98 * Paul Vixie (ISC), October 1998
101 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
107 if ((bits < -1) || (bits > 32)) {
112 /* Find number of significant bytes in address. */
116 for (len = 1, b = 1 ; b < 4U; b++)
120 /* Format whole octets plus nonzero trailing octets. */
121 bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
124 b = decoct(src, bytes, dst, size);
131 /* Format CIDR /width. */
132 if (size < sizeof "/32")
134 dst += sprintf(dst, "/%u", bits);
145 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
147 * Note that int32_t and int16_t need only be "at least" large enough
148 * to contain a value of the specified size. On some systems, like
149 * Crays, there is no such thing as an integer variable with 16 bits.
150 * Keep this in mind if you think this function should have been coded
151 * to use pointer overlays. All the world's not a VAX.
153 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
155 struct { int base, len; } best, cur;
156 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
159 if ((bits < -1) || (bits > 128)) {
166 * Copy the input (bytewise) array into a wordwise array.
167 * Find the longest run of 0x00's in src[] for :: shorthanding.
169 memset(words, '\0', sizeof words);
170 for (i = 0; i < NS_IN6ADDRSZ; i++)
171 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
176 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
179 cur.base = i, cur.len = 1;
183 if (cur.base != -1) {
184 if (best.base == -1 || cur.len > best.len)
190 if (cur.base != -1) {
191 if (best.base == -1 || cur.len > best.len)
194 if (best.base != -1 && best.len < 2)
201 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
202 /* Are we inside the best run of 0x00's? */
203 if (best.base != -1 && i >= best.base &&
204 i < (best.base + best.len)) {
209 /* Are we following an initial run of 0x00s or any real hex? */
212 /* Is this address an encapsulated IPv4? */
213 if (i == 6 && best.base == 0 && (best.len == 6 ||
214 (best.len == 7 && words[7] != 0x0001) ||
215 (best.len == 5 && words[5] == 0xffff))) {
218 if (src[15] || bits == -1 || bits > 120)
220 else if (src[14] || bits > 112)
224 n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
232 tp += sprintf(tp, "%x", words[i]);
235 /* Was it a trailing run of 0x00's? */
236 if (best.base != -1 && (best.base + best.len) ==
237 (NS_IN6ADDRSZ / NS_INT16SZ))
242 tp += sprintf(tp, "/%u", bits);
245 * Check for overflow, copy, and we're done.
247 if ((size_t)(tp - tmp) > size) {