1: /*
2: * Copyright (C) 1996-2001 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
9: * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
11: * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
12: * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13: * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14: * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15: * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16: */
17:
18:
19: #include "rsync.h"
20:
21: #define NS_INT16SZ 2
22: #define NS_IN6ADDRSZ 16
23:
24: /*
25: * WARNING: Don't even consider trying to compile this on a system where
26: * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
27: */
28:
29: static const char *inet_ntop4(const unsigned char *src, char *dst,
30: size_t size);
31:
32: #ifdef AF_INET6
33: static const char *inet_ntop6(const unsigned char *src, char *dst,
34: size_t size);
35: #endif
36:
37: /* char *
38: * isc_net_ntop(af, src, dst, size)
39: * convert a network format address to presentation format.
40: * return:
41: * pointer to presentation format address (`dst'), or NULL (see errno).
42: * author:
43: * Paul Vixie, 1996.
44: */
45: const char *
46: inet_ntop(int af, const void *src, char *dst, size_t size)
47: {
48: switch (af) {
49: case AF_INET:
50: return (inet_ntop4(src, dst, size));
51: #ifdef AF_INET6
52: case AF_INET6:
53: return (inet_ntop6(src, dst, size));
54: #endif
55: default:
56: errno = EAFNOSUPPORT;
57: return (NULL);
58: }
59: /* NOTREACHED */
60: }
61:
62: /* const char *
63: * inet_ntop4(src, dst, size)
64: * format an IPv4 address
65: * return:
66: * `dst' (as a const)
67: * notes:
68: * (1) uses no statics
69: * (2) takes a unsigned char* not an in_addr as input
70: * author:
71: * Paul Vixie, 1996.
72: */
73: static const char *
74: inet_ntop4(const unsigned char *src, char *dst, size_t size)
75: {
76: static const char *fmt = "%u.%u.%u.%u";
77: char tmp[sizeof "255.255.255.255"];
78: size_t len;
79:
80: len = snprintf(tmp, sizeof tmp, fmt, src[0], src[1], src[2], src[3]);
81: if (len >= size) {
82: errno = ENOSPC;
83: return (NULL);
84: }
85: memcpy(dst, tmp, len + 1);
86:
87: return (dst);
88: }
89:
90: /* const char *
91: * isc_inet_ntop6(src, dst, size)
92: * convert IPv6 binary address into presentation (printable) format
93: * author:
94: * Paul Vixie, 1996.
95: */
96: #ifdef AF_INET6
97: static const char *
98: inet_ntop6(const unsigned char *src, char *dst, size_t size)
99: {
100: /*
101: * Note that int32_t and int16_t need only be "at least" large enough
102: * to contain a value of the specified size. On some systems, like
103: * Crays, there is no such thing as an integer variable with 16 bits.
104: * Keep this in mind if you think this function should have been coded
105: * to use pointer overlays. All the world's not a VAX.
106: */
107: char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
108: struct { int base, len; } best, cur;
109: unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
110: int i, inc;
111:
112: /*
113: * Preprocess:
114: * Copy the input (bytewise) array into a wordwise array.
115: * Find the longest run of 0x00's in src[] for :: shorthanding.
116: */
117: memset(words, '\0', sizeof words);
118: for (i = 0; i < NS_IN6ADDRSZ; i++)
119: words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
120: best.base = -1;
121: cur.base = -1;
122: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
123: if (words[i] == 0) {
124: if (cur.base == -1)
125: cur.base = i, cur.len = 1;
126: else
127: cur.len++;
128: } else {
129: if (cur.base != -1) {
130: if (best.base == -1 || cur.len > best.len)
131: best = cur;
132: cur.base = -1;
133: }
134: }
135: }
136: if (cur.base != -1) {
137: if (best.base == -1 || cur.len > best.len)
138: best = cur;
139: }
140: if (best.base != -1 && best.len < 2)
141: best.base = -1;
142:
143: /*
144: * Format the result.
145: */
146: tp = tmp;
147: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
148: /* Are we inside the best run of 0x00's? */
149: if (best.base != -1 && i >= best.base &&
150: i < (best.base + best.len)) {
151: if (i == best.base)
152: *tp++ = ':';
153: continue;
154: }
155: /* Are we following an initial run of 0x00s or any real hex? */
156: if (i != 0)
157: *tp++ = ':';
158: /* Is this address an encapsulated IPv4? */
159: if (i == 6 && best.base == 0 &&
160: (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
161: if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
162: return (NULL);
163: tp += strlen(tp);
164: break;
165: }
166: inc = snprintf(tp, 5, "%x", words[i]);
167: assert(inc < 5);
168: tp += inc;
169: }
170: /* Was it a trailing run of 0x00's? */
171: if (best.base != -1 && (best.base + best.len) ==
172: (NS_IN6ADDRSZ / NS_INT16SZ))
173: *tp++ = ':';
174: *tp++ = '\0';
175:
176: /*
177: * Check for overflow, copy, and we're done.
178: */
179: if ((size_t)(tp - tmp) > size) {
180: errno = ENOSPC;
181: return (NULL);
182: }
183: memcpy(dst, tmp, tp - tmp);
184: return (dst);
185: }
186: #endif /* AF_INET6 */
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