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r15882@catbus: nickm | 2007-10-17 15:23:05 -0400

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oprofile was telling me that a fair bit of our time in openssl was spent in base64_decode, so replace base64_decode with an all-at-once fairly optimized implementation.  For decoding keys and digests, it seems 3-3.5x faster than calling out to openssl.  (Yes, I wrote it from scratch.)


svn:r12002
This commit is contained in:
Nick Mathewson 2007-10-17 19:23:56 +00:00
parent e8bd32b347
commit e3113502ad
3 changed files with 135 additions and 6 deletions
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6
ChangeLog
View File

@ -49,6 +49,12 @@ Changes in version 0.2.0.9-alpha - 2007-10-??
- Make base32_decode() accept upper-case letters. Bugfix on
0.2.0.7-alpha.
o Minor bugfixes (performance):
- Base64 decoding was actually showing up on our profile when parsing
the initial descriptor file; switch to an in-process all-at-once
implementation that's about 3.5x times faster than calling out to
OpenSSL.
o Code simplifications and refactoring:
- Remove support for the old bw_accounting file: we've been storing
bandwidth accounting information in the state file since 0.1.2.5-alpha.

120
src/common/crypto.c
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@ -1768,6 +1768,8 @@ smartlist_shuffle(smartlist_t *sl)
int
base64_encode(char *dest, size_t destlen, const char *src, size_t srclen)
{
/* XXXX we might want to rewrite this along the lines of base64_decode, if
* it ever shows up in the profile. */
EVP_ENCODE_CTX ctx;
int len, ret;
@ -1787,18 +1789,48 @@ base64_encode(char *dest, size_t destlen, const char *src, size_t srclen)
return ret;
}
#define X 255
#define SP 64
#define PAD 65
/** Internal table mapping byte values to what they represent in base64.
* Numbers 0..63 are 6-bit integers. SPs are spaces, and should be
* skipped. Xs are invalid and must not appear in base64. PAD indicates
* end-of-string. */
static const uint8_t base64_decode_table[256] = {
X, X, X, X, X, X, X, X, X, SP, SP, SP, X, SP, X, X, /* */
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
SP, X, X, X, X, X, X, X, X, X, X, 62, X, X, X, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, X, X, X, PAD, X, X,
X, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, X, X, X, X, X,
X, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X,
};
/** Base-64 decode <b>srclen</b> bytes of data from <b>src</b>. Write
* the result into <b>dest</b>, if it will fit within <b>destlen</b>
* bytes. Return the number of bytes written on success; -1 if
* destlen is too short, or other failure.
*
* NOTE: destlen should be a little longer than the amount of data it
* will contain, since we check for sufficient space conservatively.
* Here, "a little" is around 64-ish bytes.
* NOTE 1: destlen is checked conservatively, as though srclen contained no
* spaces or padding.
*
* NOTE 2: This implementation does not check for the correct number of
* padding "=" characters at the end of the string, and does not check
* for internal padding characters.
*/
int
base64_decode(char *dest, size_t destlen, const char *src, size_t srclen)
{
#ifdef USE_OPENSSL_BASE64
EVP_ENCODE_CTX ctx;
int len, ret;
/* 64 bytes of input -> *up to* 48 bytes of output.
@ -1815,7 +1847,80 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen)
EVP_DecodeFinal(&ctx, (unsigned char*)dest, &ret);
ret += len;
return ret;
#else
#define ACC32
const char *eos = src+srclen;
uint32_t n=0;
int n_idx=0;
char *dest_orig = dest;
/* Max number of bits == srclen*6.
* Number of bytes required to hold all bits == (srclen*6)/8.
* Yes, we want to round down: anything that hangs over the end of a
* byte is padding. */
if (destlen < (srclen*3)/4)
return -1;
if (destlen > SIZE_T_CEILING)
return -1;
/* Iterate over all the bytes in src. Each one will add 0 or 6 bits to the
* value we're decoding. Accumulate bits in <b>n</b>, and whenever we have
* 24 bits, batch them into 3 bytes and flush those bytes to dest.
*/
for ( ; src < eos; ++src) {
unsigned char c = (unsigned char) *src;
uint8_t v = base64_decode_table[c];
switch (v) {
case X:
/* This character isn't allowed in base64. */
return -1;
case SP:
/* This character is whitespace, and has no effect. */
continue;
case PAD:
/* We've hit an = character: the data is over. */
goto end_of_loop;
default:
/* We have an actual 6-bit value. Append it to the bits in n. */
n = (n<<6) | v;
if ((++n_idx) == 4) {
/* We've accumulated 24 bits in n. Flush them. */
*dest++ = (n>>16);
*dest++ = (n>>8) & 0xff;
*dest++ = (n) & 0xff;
n_idx = 0;
n = 0;
}
}
}
end_of_loop:
/* If we have leftover bits, we need to cope. */
switch (n_idx) {
case 0:
default:
/* No leftover bits. We win. */
break;
case 1:
/* 6 leftover bits. That's invalid; we can't form a byte out of that. */
return -1;
case 2:
/* 12 leftover bits: The last 4 are padding and the first 8 are data. */
*dest++ = n >> 4;
break;
case 3:
/* 18 leftover bits: The last 2 are padding and the first 16 are data. */
*dest++ = n >> 10;
*dest++ = n >> 2;
}
tor_assert((dest-dest_orig) <= (ssize_t)destlen);
return dest-dest_orig;
#endif
}
#undef X
#undef SP
#undef NIL
/** Base-64 encode DIGEST_LINE bytes from <b>digest</b>, remove the trailing =
* and newline characters, and store the nul-terminated result in the first
@ -1836,6 +1941,7 @@ digest_to_base64(char *d64, const char *digest)
int
digest_from_base64(char *digest, const char *d64)
{
#ifdef USE_OPENSSL_BASE64
char buf_in[BASE64_DIGEST_LEN+3];
char buf[256];
if (strlen(d64) != BASE64_DIGEST_LEN)
@ -1846,6 +1952,12 @@ digest_from_base64(char *digest, const char *d64)
return -1;
memcpy(digest, buf, DIGEST_LEN);
return 0;
#else
if (base64_decode(digest, DIGEST_LEN, d64, strlen(d64)) == DIGEST_LEN)
return 0;
else
return -1;
#endif
}
/** Implements base32 encoding as in rfc3548. Limitation: Requires
@ -1878,6 +1990,8 @@ base32_encode(char *dest, size_t destlen, const char *src, size_t srclen)
int
base32_decode(char *dest, size_t destlen, const char *src, size_t srclen)
{
/* XXXX we might want to rewrite this along the lines of base64_decode, if
* it ever shows up in the profile. */
unsigned int nbits, i, j, bit;
char *tmp;
nbits = srclen * 5;

15
src/or/test.c
View File

@ -363,7 +363,7 @@ test_crypto(void)
crypto_cipher_env_t *env1, *env2;
crypto_pk_env_t *pk1, *pk2;
char *data1, *data2, *data3, *cp;
int i, j, p, len;
int i, j, p, len, idx;
size_t size;
data1 = tor_malloc(1024);
@ -528,13 +528,21 @@ test_crypto(void)
crypto_free_pk_env(pk2);
/* Base64 tests */
memset(data1, 6, 1024);
for (idx = 0; idx < 10; ++idx) {
i = base64_encode(data2, 1024, data1, idx);
j = base64_decode(data3, 1024, data2, i);
test_eq(j,idx);
test_memeq(data3, data1, idx);
}
strlcpy(data1, "Test string that contains 35 chars.", 1024);
strlcat(data1, " 2nd string that contains 35 chars.", 1024);
i = base64_encode(data2, 1024, data1, 71);
j = base64_decode(data3, 1024, data2, i);
test_streq(data3, data1);
test_eq(j, 71);
test_streq(data3, data1);
test_assert(data2[i] == '\0');
crypto_rand(data1, DIGEST_LEN);
@ -543,7 +551,7 @@ test_crypto(void)
test_eq(BASE64_DIGEST_LEN, strlen(data2));
test_eq(100, data2[BASE64_DIGEST_LEN+2]);
memset(data3, 99, 1024);
digest_from_base64(data3, data2);
test_eq(digest_from_base64(data3, data2), 0);
test_memeq(data1, data3, DIGEST_LEN);
test_eq(99, data3[DIGEST_LEN+1]);
@ -2639,6 +2647,7 @@ test_v3_networkstatus(void)
v3_text = format_networkstatus_vote(sign_skey_3, vote);
test_assert(v3_text);
v3 = networkstatus_parse_vote_from_string(v3_text, NULL, 1);
test_assert(v3);