linux/fs/ceph/armor.c

100 lines
1.8 KiB
C

#include <linux/errno.h>
/*
* base64 encode/decode.
*/
const char *pem_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static int encode_bits(int c)
{
return pem_key[c];
}
static int decode_bits(char c)
{
if (c >= 'A' && c <= 'Z')
return c - 'A';
if (c >= 'a' && c <= 'z')
return c - 'a' + 26;
if (c >= '0' && c <= '9')
return c - '0' + 52;
if (c == '+')
return 62;
if (c == '/')
return 63;
if (c == '=')
return 0; /* just non-negative, please */
return -EINVAL;
}
int ceph_armor(char *dst, const char *src, const char *end)
{
int olen = 0;
int line = 0;
while (src < end) {
unsigned char a, b, c;
a = *src++;
*dst++ = encode_bits(a >> 2);
if (src < end) {
b = *src++;
*dst++ = encode_bits(((a & 3) << 4) | (b >> 4));
if (src < end) {
c = *src++;
*dst++ = encode_bits(((b & 15) << 2) |
(c >> 6));
*dst++ = encode_bits(c & 63);
} else {
*dst++ = encode_bits((b & 15) << 2);
*dst++ = '=';
}
} else {
*dst++ = encode_bits(((a & 3) << 4));
*dst++ = '=';
*dst++ = '=';
}
olen += 4;
line += 4;
if (line == 64) {
line = 0;
*(dst++) = '\n';
olen++;
}
}
return olen;
}
int ceph_unarmor(char *dst, const char *src, const char *end)
{
int olen = 0;
while (src < end) {
int a, b, c, d;
if (src < end && src[0] == '\n')
src++;
if (src + 4 > end)
return -EINVAL;
a = decode_bits(src[0]);
b = decode_bits(src[1]);
c = decode_bits(src[2]);
d = decode_bits(src[3]);
if (a < 0 || b < 0 || c < 0 || d < 0)
return -EINVAL;
*dst++ = (a << 2) | (b >> 4);
if (src[2] == '=')
return olen + 1;
*dst++ = ((b & 15) << 4) | (c >> 2);
if (src[3] == '=')
return olen + 2;
*dst++ = ((c & 3) << 6) | d;
olen += 3;
src += 4;
}
return olen;
}