token: Fix uint32_t to uint64_t conversion

Unfortunately, the units passed to
monotime_coarse_stamp_units_to_approx_msec() was always 0 due to a type
conversion.

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/common/token_bucket.c

@@ -108,7 +108,7 @@ token_bucket_raw_dec(token_bucket_raw_t *bucket,
 }
 
 /** Convert a rate in bytes per second to a rate in bytes per step */
-static uint32_t
+STATIC uint32_t
 rate_per_sec_to_rate_per_step(uint32_t rate)
 {
   /*
@@ -117,8 +117,9 @@ rate_per_sec_to_rate_per_step(uint32_t rate)
     (rate / 1000) * to_approximate_msec(TICKS_PER_STEP).  But to minimize
     rounding error, we do it this way instead, and divide last.
   */
+  uint64_t units = (uint64_t) rate * TICKS_PER_STEP;
   uint32_t val = (uint32_t)
-    monotime_coarse_stamp_units_to_approx_msec(rate*TICKS_PER_STEP)/1000;
+    monotime_coarse_stamp_units_to_approx_msec(units) / 1000;
   return val ? val : 1;
 }
 

src/common/token_bucket.h

@@ -10,6 +10,7 @@
 #define TOR_TOKEN_BUCKET_H
 
 #include "torint.h"
+#include "testsupport.h"
 
 /** Largest allowable burst value for a token buffer. */
 #define TOKEN_BUCKET_MAX_BURST INT32_MAX
@@ -109,6 +110,8 @@ token_bucket_rw_get_write(const token_bucket_rw_t *bucket)
  * a power of two if you can. */
 #define TICKS_PER_STEP 16
 
+STATIC uint32_t rate_per_sec_to_rate_per_step(uint32_t rate);
+
 #endif
 
 #endif /* TOR_TOKEN_BUCKET_H */