Merge GH #373 RDRAND/RDSEED logic changes

The Intel RNG may fail if heavily contended, so retry as needed.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/build-data/buildh.in b/src/build-data/buildh.in
index a1d8890db..6412fdcdf 100644
--- a/src/build-data/buildh.in
+++ b/src/build-data/buildh.in
@@ -167,6 +167,22 @@ softare-based entropy polling is still used.
 */
 #define BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG 0.0
 
+/*
+How often should the RdRand/RdSeed RNGs be polled
+
+Each poll generates 32 bit entropy
+*/
+#define BOTAN_ENTROPY_INTEL_RNG_POLLS 32
+
+// According to Intel RdRand is guaranteed to generate a random number within 10 retries on a working CPU
+#define BOTAN_ENTROPY_RDRAND_RETRIES 10
+
+/*
+* RdSeed is not guaranteed to generate a random number within a specific number of retries
+* Define the number of retries here
+*/
+#define BOTAN_ENTROPY_RDSEED_RETRIES 20
+
 // The output of a PRNG we are trusting to be strong
 #define BOTAN_ENTROPY_ESTIMATE_STRONG_RNG 7.0