diff options
| -rw-r--r-- | src/include/gnunet_common.h | 7 | ||||
| -rw-r--r-- | src/include/gnunet_crypto_lib.h | 16 | ||||
| -rw-r--r-- | src/util/crypto_random.c | 44 | ||||
| -rw-r--r-- | src/util/test_crypto_random.c | 3 |
4 files changed, 65 insertions, 5 deletions
diff --git a/src/include/gnunet_common.h b/src/include/gnunet_common.h index 707108289..4dab71f7f 100644 --- a/src/include/gnunet_common.h +++ b/src/include/gnunet_common.h @@ -256,7 +256,12 @@ struct GNUNET_ShortHashCode /** - * A UUID, a 128 bit random value. + * A UUID, a 128 bit "random" value. We OFTEN use + * timeflakes (see: https://github.com/anthonynsimon/timeflake), + * where only 80 bits are random and the rest encodes + * a timestamp to improve database access. + * + * See #GNUNET_CRYPTO_random_timeflake(). */ struct GNUNET_Uuid { diff --git a/src/include/gnunet_crypto_lib.h b/src/include/gnunet_crypto_lib.h index 5521dad3c..d01457b4a 100644 --- a/src/include/gnunet_crypto_lib.h +++ b/src/include/gnunet_crypto_lib.h @@ -475,6 +475,22 @@ GNUNET_CRYPTO_random_block (enum GNUNET_CRYPTO_Quality mode, void *buffer, size_t length); + +/** + * @ingroup crypto + * Fill UUID with a timeflake pseudo-random value. Note that + * timeflakes use only 80 bits of randomness and 48 bits + * to encode a timestamp in milliseconds. So what we return + * here is not a completely random number. + * + * @param mode desired quality of the random number + * @param uuid the value to fill + */ +void +GNUNET_CRYPTO_random_timeflake (enum GNUNET_CRYPTO_Quality mode, + struct GNUNET_Uuid *uuid); + + /** * @ingroup crypto * Produce a random value. diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c index ffcabd0df..0c5d6fe7e 100644 --- a/src/util/crypto_random.c +++ b/src/util/crypto_random.c @@ -26,6 +26,7 @@ */ #include "platform.h" #include "gnunet_crypto_lib.h" +#include "gnunet_time_lib.h" #include <gcrypt.h> #define LOG(kind, ...) GNUNET_log_from (kind, "util-crypto-random", __VA_ARGS__) @@ -80,7 +81,7 @@ glibc_weak_rand32 () * @return number between 0 and 1. */ static double -get_weak_random () +get_weak_random (void) { return((double) random () / RAND_MAX); } @@ -176,7 +177,8 @@ GNUNET_CRYPTO_random_block (enum GNUNET_CRYPTO_Quality mode, * @return a random value in the interval [0,i[. */ uint32_t -GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i) +GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, + uint32_t i) { #ifdef gcry_fast_random_poll static unsigned int invokeCount; @@ -235,7 +237,8 @@ GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i) * @return the permutation array (allocated from heap) */ unsigned int * -GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n) +GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, + unsigned int n) { unsigned int *ret; unsigned int i; @@ -265,7 +268,8 @@ GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n) * @return random 64-bit number */ uint64_t -GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) +GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, + uint64_t max) { uint64_t ret; uint64_t ul; @@ -308,6 +312,38 @@ GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max) /** + * @ingroup crypto + * Fill UUID with a timeflake pseudo-random value. Note that + * timeflakes use only 80 bits of randomness and 48 bits + * to encode a timestamp in milliseconds. So what we return + * here is not a completely random number. + * + * @param mode desired quality of the random number + * @param uuid the value to fill + */ +void +GNUNET_CRYPTO_random_timeflake (enum GNUNET_CRYPTO_Quality mode, + struct GNUNET_Uuid *uuid) +{ + struct GNUNET_TIME_Absolute now; + uint64_t ms; + uint64_t be; + char *base; + + GNUNET_CRYPTO_random_block (mode, + uuid, + sizeof (struct GNUNET_Uuid)); + now = GNUNET_TIME_absolute_get (); + ms = now.abs_value_us / GNUNET_TIME_UNIT_MILLISECONDS.rel_value_us; + be = GNUNET_htonll (ms); + base = (char *) &be; + memcpy (uuid, + base + 2, + sizeof (be) - 2); +} + + +/** * Allocation wrapper for libgcrypt, used to avoid bad locking * strategy of libgcrypt implementation. */ diff --git a/src/util/test_crypto_random.c b/src/util/test_crypto_random.c index 5e159d949..b9cbbdf76 100644 --- a/src/util/test_crypto_random.c +++ b/src/util/test_crypto_random.c @@ -33,6 +33,7 @@ test (enum GNUNET_CRYPTO_Quality mode) unsigned int *b2; int i; unsigned long long n; + struct GNUNET_Uuid tf; for (i = 0; i < 1024; i++) GNUNET_break (1024 > (buf[i] = GNUNET_CRYPTO_random_u32 (mode, 1024))); @@ -53,6 +54,8 @@ test (enum GNUNET_CRYPTO_Quality mode) for (n = 10; n < 1024LL * 1024LL * 1024LL; n *= 10) GNUNET_break (n > GNUNET_CRYPTO_random_u64 (mode, n)); + GNUNET_CRYPTO_random_timeflake (mode, + &tf); return 0; } |