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-rw-r--r--libc/inet/resolv.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index c05f18980..ed2e0d2fa 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -3632,6 +3632,263 @@ void res_close(void)
}
#endif
+#ifdef __UCLIBC_HAS_BSD_B64_NTOP_B64_PTON__
+#define Assert(Cond) if (!(Cond)) abort()
+
+static const char Base64[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+static const char Pad64 = '=';
+
+/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
+ The following encoding technique is taken from RFC 1521 by Borenstein
+ and Freed. It is reproduced here in a slightly edited form for
+ convenience.
+
+ A 65-character subset of US-ASCII is used, enabling 6 bits to be
+ represented per printable character. (The extra 65th character, "=",
+ is used to signify a special processing function.)
+
+ The encoding process represents 24-bit groups of input bits as output
+ strings of 4 encoded characters. Proceeding from left to right, a
+ 24-bit input group is formed by concatenating 3 8-bit input groups.
+ These 24 bits are then treated as 4 concatenated 6-bit groups, each
+ of which is translated into a single digit in the base64 alphabet.
+
+ Each 6-bit group is used as an index into an array of 64 printable
+ characters. The character referenced by the index is placed in the
+ output string.
+
+ Table 1: The Base64 Alphabet
+
+ Value Encoding Value Encoding Value Encoding Value Encoding
+ 0 A 17 R 34 i 51 z
+ 1 B 18 S 35 j 52 0
+ 2 C 19 T 36 k 53 1
+ 3 D 20 U 37 l 54 2
+ 4 E 21 V 38 m 55 3
+ 5 F 22 W 39 n 56 4
+ 6 G 23 X 40 o 57 5
+ 7 H 24 Y 41 p 58 6
+ 8 I 25 Z 42 q 59 7
+ 9 J 26 a 43 r 60 8
+ 10 K 27 b 44 s 61 9
+ 11 L 28 c 45 t 62 +
+ 12 M 29 d 46 u 63 /
+ 13 N 30 e 47 v
+ 14 O 31 f 48 w (pad) =
+ 15 P 32 g 49 x
+ 16 Q 33 h 50 y
+
+ Special processing is performed if fewer than 24 bits are available
+ at the end of the data being encoded. A full encoding quantum is
+ always completed at the end of a quantity. When fewer than 24 input
+ bits are available in an input group, zero bits are added (on the
+ right) to form an integral number of 6-bit groups. Padding at the
+ end of the data is performed using the '=' character.
+
+ Since all base64 input is an integral number of octets, only the
+ -------------------------------------------------
+ following cases can arise:
+
+ (1) the final quantum of encoding input is an integral
+ multiple of 24 bits; here, the final unit of encoded
+ output will be an integral multiple of 4 characters
+ with no "=" padding,
+ (2) the final quantum of encoding input is exactly 8 bits;
+ here, the final unit of encoded output will be two
+ characters followed by two "=" padding characters, or
+ (3) the final quantum of encoding input is exactly 16 bits;
+ here, the final unit of encoded output will be three
+ characters followed by one "=" padding character.
+ */
+
+int
+b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) {
+ size_t datalength = 0;
+ u_char input[3];
+ u_char output[4];
+ size_t i;
+
+ while (2 < srclength) {
+ input[0] = *src++;
+ input[1] = *src++;
+ input[2] = *src++;
+ srclength -= 3;
+
+ output[0] = input[0] >> 2;
+ output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
+ output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
+ output[3] = input[2] & 0x3f;
+ Assert(output[0] < 64);
+ Assert(output[1] < 64);
+ Assert(output[2] < 64);
+ Assert(output[3] < 64);
+
+ if (datalength + 4 > targsize)
+ return (-1);
+ target[datalength++] = Base64[output[0]];
+ target[datalength++] = Base64[output[1]];
+ target[datalength++] = Base64[output[2]];
+ target[datalength++] = Base64[output[3]];
+ }
+
+ /* Now we worry about padding. */
+ if (0 != srclength) {
+ /* Get what's left. */
+ input[0] = input[1] = input[2] = '\0';
+ for (i = 0; i < srclength; i++)
+ input[i] = *src++;
+
+ output[0] = input[0] >> 2;
+ output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
+ output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
+ Assert(output[0] < 64);
+ Assert(output[1] < 64);
+ Assert(output[2] < 64);
+
+ if (datalength + 4 > targsize)
+ return (-1);
+ target[datalength++] = Base64[output[0]];
+ target[datalength++] = Base64[output[1]];
+ if (srclength == 1)
+ target[datalength++] = Pad64;
+ else
+ target[datalength++] = Base64[output[2]];
+ target[datalength++] = Pad64;
+ }
+ if (datalength >= targsize)
+ return (-1);
+ target[datalength] = '\0'; /* Returned value doesn't count \0. */
+ return (datalength);
+}
+/* libc_hidden_def (b64_ntop) */
+
+/* skips all whitespace anywhere.
+ converts characters, four at a time, starting at (or after)
+ src from base - 64 numbers into three 8 bit bytes in the target area.
+ it returns the number of data bytes stored at the target, or -1 on error.
+ */
+
+int
+b64_pton (char const *src, u_char *target, size_t targsize)
+{
+ int tarindex, state, ch;
+ char *pos;
+
+ state = 0;
+ tarindex = 0;
+
+ while ((ch = *src++) != '\0') {
+ if (isspace(ch)) /* Skip whitespace anywhere. */
+ continue;
+
+ if (ch == Pad64)
+ break;
+
+ pos = strchr(Base64, ch);
+ if (pos == 0) /* A non-base64 character. */
+ return (-1);
+
+ switch (state) {
+ case 0:
+ if (target) {
+ if ((size_t)tarindex >= targsize)
+ return (-1);
+ target[tarindex] = (pos - Base64) << 2;
+ }
+ state = 1;
+ break;
+ case 1:
+ if (target) {
+ if ((size_t)tarindex + 1 >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64) >> 4;
+ target[tarindex+1] = ((pos - Base64) & 0x0f)
+ << 4 ;
+ }
+ tarindex++;
+ state = 2;
+ break;
+ case 2:
+ if (target) {
+ if ((size_t)tarindex + 1 >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64) >> 2;
+ target[tarindex+1] = ((pos - Base64) & 0x03)
+ << 6;
+ }
+ tarindex++;
+ state = 3;
+ break;
+ case 3:
+ if (target) {
+ if ((size_t)tarindex >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64);
+ }
+ tarindex++;
+ state = 0;
+ break;
+ default:
+ abort();
+ }
+ }
+
+ /*
+ * We are done decoding Base-64 chars. Let's see if we ended
+ * on a byte boundary, and/or with erroneous trailing characters.
+ */
+
+ if (ch == Pad64) { /* We got a pad char. */
+ ch = *src++; /* Skip it, get next. */
+ switch (state) {
+ case 0: /* Invalid = in first position */
+ case 1: /* Invalid = in second position */
+ return (-1);
+
+ case 2: /* Valid, means one byte of info */
+ /* Skip any number of spaces. */
+ for ((void)NULL; ch != '\0'; ch = *src++)
+ if (!isspace(ch))
+ break;
+ /* Make sure there is another trailing = sign. */
+ if (ch != Pad64)
+ return (-1);
+ ch = *src++; /* Skip the = */
+ /* Fall through to "single trailing =" case. */
+ /* FALLTHROUGH */
+
+ case 3: /* Valid, means two bytes of info */
+ /*
+ * We know this char is an =. Is there anything but
+ * whitespace after it?
+ */
+ for ((void)NULL; ch != '\0'; ch = *src++)
+ if (!isspace(ch))
+ return (-1);
+
+ /*
+ * Now make sure for cases 2 and 3 that the "extra"
+ * bits that slopped past the last full byte were
+ * zeros. If we don't check them, they become a
+ * subliminal channel.
+ */
+ if (target && target[tarindex] != 0)
+ return (-1);
+ }
+ } else {
+ /*
+ * We ended by seeing the end of the string. Make sure we
+ * have no partial bytes lying around.
+ */
+ if (state != 0)
+ return (-1);
+ }
+
+ return (tarindex);
+}
+#endif
+
/* This needs to be after the use of _res in res_init, above. */
#undef _res
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 22:35:51 +0000