2 * Copyright (c) 1996, 1998 by Internet Software Consortium.
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
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9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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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
19 * Portions Copyright (c) 1995 by International Business Machines, Inc.
21 * International Business Machines, Inc. (hereinafter called IBM) grants
22 * permission under its copyrights to use, copy, modify, and distribute this
23 * Software with or without fee, provided that the above copyright notice and
24 * all paragraphs of this notice appear in all copies, and that the name of IBM
25 * not be used in connection with the marketing of any product incorporating
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29 * To the extent it has a right to do so, IBM grants an immunity from suit
30 * under its patents, if any, for the use, sale or manufacture of products to
31 * the extent that such products are used for performing Domain Name System
32 * dynamic updates in TCP/IP networks by means of the Software. No immunity is
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42 #include <ldns/config.h>
45 #include <sys/types.h>
46 #include <sys/param.h>
47 #ifdef HAVE_SYS_SOCKET_H
48 #include <sys/socket.h>
51 #ifdef HAVE_NETINET_IN_H
52 #include <netinet/in.h>
54 #ifdef HAVE_ARPA_INET_H
55 #include <arpa/inet.h>
63 #include <ldns/util.h>
65 #define Assert(Cond) if (!(Cond)) abort()
67 static const char Base64[] =
68 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
69 static const char Pad64 = '=';
71 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
72 The following encoding technique is taken from RFC 1521 by Borenstein
73 and Freed. It is reproduced here in a slightly edited form for
76 A 65-character subset of US-ASCII is used, enabling 6 bits to be
77 represented per printable character. (The extra 65th character, "=",
78 is used to signify a special processing function.)
80 The encoding process represents 24-bit groups of input bits as output
81 strings of 4 encoded characters. Proceeding from left to right, a
82 24-bit input group is formed by concatenating 3 8-bit input groups.
83 These 24 bits are then treated as 4 concatenated 6-bit groups, each
84 of which is translated into a single digit in the base64 alphabet.
86 Each 6-bit group is used as an index into an array of 64 printable
87 characters. The character referenced by the index is placed in the
90 Table 1: The Base64 Alphabet
92 Value Encoding Value Encoding Value Encoding Value Encoding
107 14 O 31 f 48 w (pad) =
111 Special processing is performed if fewer than 24 bits are available
112 at the end of the data being encoded. A full encoding quantum is
113 always completed at the end of a quantity. When fewer than 24 input
114 bits are available in an input group, zero bits are added (on the
115 right) to form an integral number of 6-bit groups. Padding at the
116 end of the data is performed using the '=' character.
118 Since all base64 input is an integral number of octets, only the
119 -------------------------------------------------
120 following cases can arise:
122 (1) the final quantum of encoding input is an integral
123 multiple of 24 bits; here, the final unit of encoded
124 output will be an integral multiple of 4 characters
126 (2) the final quantum of encoding input is exactly 8 bits;
127 here, the final unit of encoded output will be two
128 characters followed by two "=" padding characters, or
129 (3) the final quantum of encoding input is exactly 16 bits;
130 here, the final unit of encoded output will be three
131 characters followed by one "=" padding character.
135 ldns_b64_ntop(uint8_t const *src, size_t srclength, char *target, size_t targsize) {
136 size_t datalength = 0;
141 if (srclength == 0) {
150 while (2 < srclength) {
156 output[0] = input[0] >> 2;
157 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
158 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
159 output[3] = input[2] & 0x3f;
160 Assert(output[0] < 64);
161 Assert(output[1] < 64);
162 Assert(output[2] < 64);
163 Assert(output[3] < 64);
165 if (datalength + 4 > targsize) {
168 target[datalength++] = Base64[output[0]];
169 target[datalength++] = Base64[output[1]];
170 target[datalength++] = Base64[output[2]];
171 target[datalength++] = Base64[output[3]];
174 /* Now we worry about padding. */
175 if (0 != srclength) {
176 /* Get what's left. */
177 input[0] = input[1] = input[2] = (uint8_t) '\0';
178 for (i = 0; i < srclength; i++)
181 output[0] = input[0] >> 2;
182 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
183 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
184 Assert(output[0] < 64);
185 Assert(output[1] < 64);
186 Assert(output[2] < 64);
188 if (datalength + 4 > targsize) {
191 target[datalength++] = Base64[output[0]];
192 target[datalength++] = Base64[output[1]];
193 if (srclength == 1) {
194 target[datalength++] = Pad64;
196 target[datalength++] = Base64[output[2]];
198 target[datalength++] = Pad64;
200 if (datalength >= targsize) {
203 target[datalength] = '\0'; /* Returned value doesn't count \0. */
204 return (int) (datalength);
207 #endif /* !HAVE_B64_NTOP */