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kernel/linux-imx6_3.14.28/net/ceph/armor.c 1.9 KB
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  #include <linux/errno.h>
  
  int ceph_armor(char *dst, const char *src, const char *end);
  int ceph_unarmor(char *dst, const char *src, const char *end);
  
  /*
   * base64 encode/decode.
   */
  
  static 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++) = '
  ';
  			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[0] == '
  ') {
  			src++;
  			continue;
  		}
  		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;
  }