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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 static const char Base64[] =
66 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
67 static const char Pad64 = '=';
69 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
70 The following encoding technique is taken from RFC 1521 by Borenstein
71 and Freed. It is reproduced here in a slightly edited form for
74 A 65-character subset of US-ASCII is used, enabling 6 bits to be
75 represented per printable character. (The extra 65th character, "=",
76 is used to signify a special processing function.)
78 The encoding process represents 24-bit groups of input bits as output
79 strings of 4 encoded characters. Proceeding from left to right, a
80 24-bit input group is formed by concatenating 3 8-bit input groups.
81 These 24 bits are then treated as 4 concatenated 6-bit groups, each
82 of which is translated into a single digit in the base64 alphabet.
84 Each 6-bit group is used as an index into an array of 64 printable
85 characters. The character referenced by the index is placed in the
88 Table 1: The Base64 Alphabet
90 Value Encoding Value Encoding Value Encoding Value Encoding
105 14 O 31 f 48 w (pad) =
109 Special processing is performed if fewer than 24 bits are available
110 at the end of the data being encoded. A full encoding quantum is
111 always completed at the end of a quantity. When fewer than 24 input
112 bits are available in an input group, zero bits are added (on the
113 right) to form an integral number of 6-bit groups. Padding at the
114 end of the data is performed using the '=' character.
116 Since all base64 input is an integral number of octets, only the
117 -------------------------------------------------
118 following cases can arise:
120 (1) the final quantum of encoding input is an integral
121 multiple of 24 bits; here, the final unit of encoded
122 output will be an integral multiple of 4 characters
124 (2) the final quantum of encoding input is exactly 8 bits;
125 here, the final unit of encoded output will be two
126 characters followed by two "=" padding characters, or
127 (3) the final quantum of encoding input is exactly 16 bits;
128 here, the final unit of encoded output will be three
129 characters followed by one "=" padding character.
132 /* skips all whitespace anywhere.
133 converts characters, four at a time, starting at (or after)
134 src from base - 64 numbers into three 8 bit bytes in the target area.
135 it returns the number of data bytes stored at the target, or -1 on error.
139 ldns_b64_pton(char const *src, uint8_t *target, size_t targsize)
141 int tarindex, state, ch;
147 if (strlen(src) == 0) {
151 while ((ch = *src++) != '\0') {
152 if (isspace((unsigned char)ch)) /* Skip whitespace anywhere. */
158 pos = strchr(Base64, ch);
160 /* A non-base64 character. */
167 if ((size_t)tarindex >= targsize)
169 target[tarindex] = (pos - Base64) << 2;
175 if ((size_t)tarindex + 1 >= targsize)
177 target[tarindex] |= (pos - Base64) >> 4;
178 target[tarindex+1] = ((pos - Base64) & 0x0f)
186 if ((size_t)tarindex + 1 >= targsize)
188 target[tarindex] |= (pos - Base64) >> 2;
189 target[tarindex+1] = ((pos - Base64) & 0x03)
197 if ((size_t)tarindex >= targsize)
199 target[tarindex] |= (pos - Base64);
210 * We are done decoding Base-64 chars. Let's see if we ended
211 * on a byte boundary, and/or with erroneous trailing characters.
214 if (ch == Pad64) { /* We got a pad char. */
215 ch = *src++; /* Skip it, get next. */
217 case 0: /* Invalid = in first position */
218 case 1: /* Invalid = in second position */
221 case 2: /* Valid, means one byte of info */
222 /* Skip any number of spaces. */
223 for ((void)NULL; ch != '\0'; ch = *src++)
224 if (!isspace((unsigned char)ch))
226 /* Make sure there is another trailing = sign. */
229 ch = *src++; /* Skip the = */
230 /* Fall through to "single trailing =" case. */
233 case 3: /* Valid, means two bytes of info */
235 * We know this char is an =. Is there anything but
236 * whitespace after it?
238 for ((void)NULL; ch != '\0'; ch = *src++)
239 if (!isspace((unsigned char)ch))
243 * Now make sure for cases 2 and 3 that the "extra"
244 * bits that slopped past the last full byte were
245 * zeros. If we don't check them, they become a
246 * subliminal channel.
248 if (target && target[tarindex] != 0)
253 * We ended by seeing the end of the string. Make sure we
254 * have no partial bytes lying around.
263 #endif /* !HAVE_B64_PTON */