Annotation of src/lib/libc/inet/inet_ntop.c, Revision 1.3.6.1
1.3.6.1 ! wrstuden 1: /* $NetBSD: inet_ntop.c,v 1.3.4.2 2007/05/17 21:25:14 jdc Exp $ */
1.1 christos 2:
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:
1.2 christos 20: #include <sys/cdefs.h>
1.1 christos 21: #if defined(LIBC_SCCS) && !defined(lint)
1.2 christos 22: #if 0
1.3.6.1 ! wrstuden 23: static const char rcsid[] = "Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp";
1.2 christos 24: #else
1.3.6.1 ! wrstuden 25: __RCSID("$NetBSD: inet_ntop.c,v 1.3.4.2 2007/05/17 21:25:14 jdc Exp $");
1.2 christos 26: #endif
1.1 christos 27: #endif /* LIBC_SCCS and not lint */
28:
29: #include "port_before.h"
30:
1.2 christos 31: #include "namespace.h"
1.1 christos 32: #include <sys/param.h>
33: #include <sys/types.h>
34: #include <sys/socket.h>
35:
36: #include <netinet/in.h>
37: #include <arpa/inet.h>
38: #include <arpa/nameser.h>
39:
1.2 christos 40: #include <assert.h>
1.1 christos 41: #include <errno.h>
42: #include <stdio.h>
1.2 christos 43: #include <stdlib.h>
1.1 christos 44: #include <string.h>
45:
46: #include "port_after.h"
47:
1.2 christos 48: #ifdef __weak_alias
49: __weak_alias(inet_ntop,_inet_ntop)
1.1 christos 50: #endif
51:
1.3.6.1 ! wrstuden 52: /*%
1.1 christos 53: * WARNING: Don't even consider trying to compile this on a system where
54: * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
55: */
56:
1.2 christos 57: static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
58: static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
1.1 christos 59:
60: /* char *
61: * inet_ntop(af, src, dst, size)
62: * convert a network format address to presentation format.
63: * return:
64: * pointer to presentation format address (`dst'), or NULL (see errno).
65: * author:
66: * Paul Vixie, 1996.
67: */
68: const char *
69: inet_ntop(af, src, dst, size)
70: int af;
71: const void *src;
72: char *dst;
1.2 christos 73: socklen_t size;
1.1 christos 74: {
1.2 christos 75:
76: _DIAGASSERT(src != NULL);
77: _DIAGASSERT(dst != NULL);
78:
1.1 christos 79: switch (af) {
80: case AF_INET:
81: return (inet_ntop4(src, dst, size));
82: case AF_INET6:
83: return (inet_ntop6(src, dst, size));
84: default:
85: errno = EAFNOSUPPORT;
86: return (NULL);
87: }
88: /* NOTREACHED */
89: }
90:
91: /* const char *
92: * inet_ntop4(src, dst, size)
1.2 christos 93: * format an IPv4 address, more or less like inet_ntoa()
1.1 christos 94: * return:
95: * `dst' (as a const)
96: * notes:
97: * (1) uses no statics
98: * (2) takes a u_char* not an in_addr as input
99: * author:
100: * Paul Vixie, 1996.
101: */
102: static const char *
103: inet_ntop4(src, dst, size)
104: const u_char *src;
105: char *dst;
1.2 christos 106: socklen_t size;
1.1 christos 107: {
108: char tmp[sizeof "255.255.255.255"];
1.2 christos 109: int l;
110:
111: _DIAGASSERT(src != NULL);
112: _DIAGASSERT(dst != NULL);
1.1 christos 113:
1.2 christos 114: l = snprintf(tmp, sizeof(tmp), "%u.%u.%u.%u",
115: src[0], src[1], src[2], src[3]);
116: if (l <= 0 || (socklen_t) l >= size) {
1.1 christos 117: errno = ENOSPC;
118: return (NULL);
119: }
1.2 christos 120: strlcpy(dst, tmp, size);
1.1 christos 121: return (dst);
122: }
123:
124: /* const char *
125: * inet_ntop6(src, dst, size)
126: * convert IPv6 binary address into presentation (printable) format
127: * author:
128: * Paul Vixie, 1996.
129: */
130: static const char *
131: inet_ntop6(src, dst, size)
132: const u_char *src;
133: char *dst;
1.2 christos 134: socklen_t size;
1.1 christos 135: {
136: /*
137: * Note that int32_t and int16_t need only be "at least" large enough
138: * to contain a value of the specified size. On some systems, like
139: * Crays, there is no such thing as an integer variable with 16 bits.
140: * Keep this in mind if you think this function should have been coded
141: * to use pointer overlays. All the world's not a VAX.
142: */
1.2 christos 143: char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
144: char *tp, *ep;
1.1 christos 145: struct { int base, len; } best, cur;
146: u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
147: int i;
1.2 christos 148: int advance;
149:
150: _DIAGASSERT(src != NULL);
151: _DIAGASSERT(dst != NULL);
1.1 christos 152:
153: /*
154: * Preprocess:
155: * Copy the input (bytewise) array into a wordwise array.
156: * Find the longest run of 0x00's in src[] for :: shorthanding.
157: */
158: memset(words, '\0', sizeof words);
159: for (i = 0; i < NS_IN6ADDRSZ; i++)
160: words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
161: best.base = -1;
1.3.6.1 ! wrstuden 162: best.len = 0;
1.1 christos 163: cur.base = -1;
1.3.6.1 ! wrstuden 164: cur.len = 0;
1.1 christos 165: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
166: if (words[i] == 0) {
167: if (cur.base == -1)
168: cur.base = i, cur.len = 1;
169: else
170: cur.len++;
171: } else {
172: if (cur.base != -1) {
173: if (best.base == -1 || cur.len > best.len)
174: best = cur;
175: cur.base = -1;
176: }
177: }
178: }
179: if (cur.base != -1) {
180: if (best.base == -1 || cur.len > best.len)
181: best = cur;
182: }
183: if (best.base != -1 && best.len < 2)
184: best.base = -1;
185:
186: /*
187: * Format the result.
188: */
189: tp = tmp;
1.2 christos 190: ep = tmp + sizeof(tmp);
1.1 christos 191: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
192: /* Are we inside the best run of 0x00's? */
193: if (best.base != -1 && i >= best.base &&
194: i < (best.base + best.len)) {
195: if (i == best.base)
196: *tp++ = ':';
197: continue;
198: }
199: /* Are we following an initial run of 0x00s or any real hex? */
1.2 christos 200: if (i != 0) {
201: if (tp + 1 >= ep)
202: return (NULL);
1.1 christos 203: *tp++ = ':';
1.2 christos 204: }
1.1 christos 205: /* Is this address an encapsulated IPv4? */
1.2 christos 206: if (i == 6 && best.base == 0 &&
207: (best.len == 6 ||
1.1 christos 208: (best.len == 7 && words[7] != 0x0001) ||
209: (best.len == 5 && words[5] == 0xffff))) {
1.2 christos 210: if (!inet_ntop4(src+12, tp, (socklen_t)(ep - tp)))
1.1 christos 211: return (NULL);
212: tp += strlen(tp);
213: break;
214: }
1.2 christos 215: advance = snprintf(tp, (size_t)(ep - tp), "%x", words[i]);
216: if (advance <= 0 || advance >= ep - tp)
217: return (NULL);
218: tp += advance;
1.1 christos 219: }
220: /* Was it a trailing run of 0x00's? */
221: if (best.base != -1 && (best.base + best.len) ==
1.2 christos 222: (NS_IN6ADDRSZ / NS_INT16SZ)) {
223: if (tp + 1 >= ep)
224: return (NULL);
1.1 christos 225: *tp++ = ':';
1.2 christos 226: }
227: if (tp + 1 >= ep)
228: return (NULL);
1.1 christos 229: *tp++ = '\0';
230:
231: /*
232: * Check for overflow, copy, and we're done.
233: */
234: if ((size_t)(tp - tmp) > size) {
235: errno = ENOSPC;
236: return (NULL);
237: }
1.2 christos 238: strlcpy(dst, tmp, size);
1.1 christos 239: return (dst);
240: }
1.3.6.1 ! wrstuden 241:
! 242: /*! \file */
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