2 * Copyright (c) 1996, 1998 by Internet Software Consortium.
4 * Permission to use, copy, modify, and distribute this software for any
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9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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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>
44 #include <ldns/ldns.h>
46 #include <sys/types.h>
47 #include <sys/param.h>
48 #ifdef HAVE_SYS_SOCKET_H
49 #include <sys/socket.h>
52 #ifdef HAVE_NETINET_IN_H
53 #include <netinet/in.h>
55 #ifdef HAVE_ARPA_INET_H
56 #include <arpa/inet.h>
64 #define Assert(Cond) if (!(Cond)) abort()
66 static const char Base64[] =
67 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
68 static const char Pad64 = '=';
70 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
71 The following encoding technique is taken from RFC 1521 by Borenstein
72 and Freed. It is reproduced here in a slightly edited form for
75 A 65-character subset of US-ASCII is used, enabling 6 bits to be
76 represented per printable character. (The extra 65th character, "=",
77 is used to signify a special processing function.)
79 The encoding process represents 24-bit groups of input bits as output
80 strings of 4 encoded characters. Proceeding from left to right, a
81 24-bit input group is formed by concatenating 3 8-bit input groups.
82 These 24 bits are then treated as 4 concatenated 6-bit groups, each
83 of which is translated into a single digit in the base64 alphabet.
85 Each 6-bit group is used as an index into an array of 64 printable
86 characters. The character referenced by the index is placed in the
89 Table 1: The Base64 Alphabet
91 Value Encoding Value Encoding Value Encoding Value Encoding
106 14 O 31 f 48 w (pad) =
110 Special processing is performed if fewer than 24 bits are available
111 at the end of the data being encoded. A full encoding quantum is
112 always completed at the end of a quantity. When fewer than 24 input
113 bits are available in an input group, zero bits are added (on the
114 right) to form an integral number of 6-bit groups. Padding at the
115 end of the data is performed using the '=' character.
117 Since all base64 input is an integral number of octets, only the
118 -------------------------------------------------
119 following cases can arise:
121 (1) the final quantum of encoding input is an integral
122 multiple of 24 bits; here, the final unit of encoded
123 output will be an integral multiple of 4 characters
125 (2) the final quantum of encoding input is exactly 8 bits;
126 here, the final unit of encoded output will be two
127 characters followed by two "=" padding characters, or
128 (3) the final quantum of encoding input is exactly 16 bits;
129 here, the final unit of encoded output will be three
130 characters followed by one "=" padding character.
134 ldns_b64_ntop(uint8_t const *src, size_t srclength, char *target, size_t targsize) {
135 size_t datalength = 0;
140 if (srclength == 0) {
149 while (2 < srclength) {
155 output[0] = input[0] >> 2;
156 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
157 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
158 output[3] = input[2] & 0x3f;
159 Assert(output[0] < 64);
160 Assert(output[1] < 64);
161 Assert(output[2] < 64);
162 Assert(output[3] < 64);
164 if (datalength + 4 > targsize) {
167 target[datalength++] = Base64[output[0]];
168 target[datalength++] = Base64[output[1]];
169 target[datalength++] = Base64[output[2]];
170 target[datalength++] = Base64[output[3]];
173 /* Now we worry about padding. */
174 if (0 != srclength) {
175 /* Get what's left. */
176 input[0] = input[1] = input[2] = (uint8_t) '\0';
177 for (i = 0; i < srclength; i++)
180 output[0] = input[0] >> 2;
181 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
182 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
183 Assert(output[0] < 64);
184 Assert(output[1] < 64);
185 Assert(output[2] < 64);
187 if (datalength + 4 > targsize) {
190 target[datalength++] = Base64[output[0]];
191 target[datalength++] = Base64[output[1]];
192 if (srclength == 1) {
193 target[datalength++] = Pad64;
195 target[datalength++] = Base64[output[2]];
197 target[datalength++] = Pad64;
199 if (datalength >= targsize) {
202 target[datalength] = '\0'; /* Returned value doesn't count \0. */
203 return (int) (datalength);