Start re-refactoring the token bucket interface.

Begin by creating a lowest-level triple of the types needed to
implement a token bucket: a configuration, a timestamp, and the raw
bucket itself.

Note that for low-level buckets, the units of the timestamp and the
bucket itself are unspecified: each user can use a different type.

(This patch breaks check-spaces; a later patch will fix it)

src/common/token_bucket.c

@@ -9,8 +9,9 @@
  * Tor uses these token buckets to keep track of bandwidth usage, and
  * sometimes other things too.
  *
- * The time units we use internally are based on "timestamp" units -- see
+ * There are two layers of abstraction here: "raw" token buckets, in which all
- * monotime_coarse_to_stamp() for a rationale.
+ * the pieces are decoupled, and "read-write" token buckets, which combine all
+ * the moving parts into one.
  *
  * Token buckets may become negative.
  **/
@@ -20,6 +21,51 @@
 #include "token_bucket.h"
 #include "util_bug.h"
 
+/**
+ * Set the <b>rate</b> and <b>burst</b> value in a token_bucket_cfg.
+ *
+ * Note that the <b>rate</b> value is in arbitrary units, but those units will
+ * determine the units of token_bucket_raw_dec(), token_bucket_raw_refill, and
+ * so on.
+ */
+void
+token_bucket_cfg_init(token_bucket_cfg_t *cfg,
+                      uint32_t rate,
+                      uint32_t burst)
+{
+  tor_assert_nonfatal(rate > 0);
+  tor_assert_nonfatal(burst > 0);
+  if (burst > TOKEN_BUCKET_MAX_BURST)
+    burst = TOKEN_BUCKET_MAX_BURST;
+
+  cfg->rate = rate;
+  cfg->burst = burst;
+}
+
+/**
+ * Initialize a raw token bucket and its associated timestamp to the "full"
+ * state, according to <b>cfg</b>.
+ */
+void
+token_bucket_raw_reset(token_bucket_raw_t *bucket,
+                       token_bucket_timestamp_t *stamp,
+                       const token_bucket_cfg_t *cfg,
+                       uint32_t now)
+{
+  bucket->bucket = cfg->burst;
+  stamp->last_refilled_at = now;
+}
+
+/**
+ * Adust a preexisting token bucket to respect the new configuration
+ * <b>cfg</b>, by decreasing its current level if needed. */
+void
+token_bucket_raw_adjust(token_bucket_raw_t *bucket,
+                        const token_bucket_cfg_t *cfg)
+{
+  bucket->bucket = MIN(bucket->bucket, cfg->burst);
+}
+
 /** Convert a rate in bytes per second to a rate in bytes per step */
 static uint32_t
 rate_per_sec_to_rate_per_step(uint32_t rate)
@@ -57,18 +103,14 @@ token_bucket_rw_init(token_bucket_rw_t *bucket,
  */
 void
 token_bucket_rw_adjust(token_bucket_rw_t *bucket,
-                    uint32_t rate,
+                       uint32_t rate,
-                    uint32_t burst)
+                       uint32_t burst)
 {
-  tor_assert_nonfatal(rate > 0);
+  token_bucket_cfg_init(&bucket->cfg,
-  tor_assert_nonfatal(burst > 0);
+                        rate_per_sec_to_rate_per_step(rate),
-  if (burst > TOKEN_BUCKET_RW_MAX_BURST)
+                        burst);
-    burst = TOKEN_BUCKET_RW_MAX_BURST;
+  token_bucket_raw_adjust(&bucket->read_bucket, &bucket->cfg);
-
+  token_bucket_raw_adjust(&bucket->write_bucket, &bucket->cfg);
-  bucket->rate = rate_per_sec_to_rate_per_step(rate);
-  bucket->burst = burst;
-  bucket->read_bucket = MIN(bucket->read_bucket, (int32_t)burst);
-  bucket->write_bucket = MIN(bucket->write_bucket, (int32_t)burst);
 }
 
 /**
@@ -76,36 +118,41 @@ token_bucket_rw_adjust(token_bucket_rw_t *bucket,
  */
 void
 token_bucket_rw_reset(token_bucket_rw_t *bucket,
-                   uint32_t now_ts)
+                      uint32_t now_ts)
 {
-  bucket->read_bucket = bucket->burst;
+  token_bucket_raw_reset(&bucket->read_bucket, &bucket->stamp,
-  bucket->write_bucket = bucket->burst;
+                         &bucket->cfg, now_ts);
-  bucket->last_refilled_at_ts = now_ts;
+  token_bucket_raw_reset(&bucket->write_bucket, &bucket->stamp,
+                         &bucket->cfg, now_ts);
 }
 
-/* Helper: see token_bucket_rw_refill */
+/**
-static int
+ * Given an amount of <b>elapsed</b> time units, and a bucket configuration
-refill_single_bucket(int32_t *bucketptr,
+ * <b>cfg</b>, refill the level of <b>bucket</b> accordingly.  Note that the
-                     const uint32_t rate,
+ * units of time in <b>elapsed</b> must correspond to those used to set the
-                     const int32_t burst,
+ * rate in <b>cfg</b>, or the result will be illogical.
-                     const uint32_t elapsed_steps)
+ */
+int
+token_bucket_raw_refill_steps(token_bucket_raw_t *bucket,
+                              const token_bucket_cfg_t *cfg,
+                              const uint32_t elapsed)
 {
-  const int was_empty = (*bucketptr <= 0);
+  const int was_empty = (bucket->bucket <= 0);
   /* The casts here prevent an underflow.
    *
    * Note that even if the bucket value is negative, subtracting it from
    * "burst" will still produce a correct result.  If this result is
-   * ridiculously high, then the "elapsed_steps > gap / rate" check below
+   * ridiculously high, then the "elapsed > gap / rate" check below
    * should catch it. */
-  const size_t gap = ((size_t)burst) - ((size_t)*bucketptr);
+  const size_t gap = ((size_t)cfg->burst) - ((size_t)bucket->bucket);
 
-  if (elapsed_steps > gap / rate) {
+  if (elapsed > gap / cfg->rate) {
-    *bucketptr = burst;
+    bucket->bucket = cfg->burst;
   } else {
-    *bucketptr += rate * elapsed_steps;
+    bucket->bucket += cfg->rate * elapsed;
   }
 
-  return was_empty && *bucketptr > 0;
+  return was_empty && bucket->bucket > 0;
 }
 
 /**
@@ -119,7 +166,7 @@ int
 token_bucket_rw_refill(token_bucket_rw_t *bucket,
                     uint32_t now_ts)
 {
-  const uint32_t elapsed_ticks = (now_ts - bucket->last_refilled_at_ts);
+  const uint32_t elapsed_ticks = (now_ts - bucket->stamp.last_refilled_at);
   if (elapsed_ticks > UINT32_MAX-(300*1000)) {
     /* Either about 48 days have passed since the last refill, or the
      * monotonic clock has somehow moved backwards. (We're looking at you,
@@ -132,31 +179,35 @@ token_bucket_rw_refill(token_bucket_rw_t *bucket,
 
   if (!elapsed_steps) {
     /* Note that if less than one whole step elapsed, we don't advance the
-     * time in last_refilled_at_ts. That's intentional: we want to make sure
+     * time in last_refilled_at. That's intentional: we want to make sure
      * that we add some bytes to it eventually. */
     return 0;
   }
 
   int flags = 0;
-  if (refill_single_bucket(&bucket->read_bucket,
+  if (token_bucket_raw_refill_steps(&bucket->read_bucket,
-                           bucket->rate, bucket->burst, elapsed_steps))
+                                    &bucket->cfg, elapsed_steps))
     flags |= TB_READ;
-  if (refill_single_bucket(&bucket->write_bucket,
+  if (token_bucket_raw_refill_steps(&bucket->write_bucket,
-                           bucket->rate, bucket->burst, elapsed_steps))
+                                    &bucket->cfg, elapsed_steps))
     flags |= TB_WRITE;
 
-  bucket->last_refilled_at_ts = now_ts;
+  bucket->stamp.last_refilled_at = now_ts;
   return flags;
 }
 
-static int
+/**
-decrement_single_bucket(int32_t *bucketptr,
+ * Decrement a provided bucket by <b>n</b> units.  Note that <b>n</b>
-                        ssize_t n)
+ * must be nonnegative.
+ */
+int
+token_bucket_raw_dec(token_bucket_raw_t *bucket,
+                     ssize_t n)
 {
   if (BUG(n < 0))
     return 0;
-  const int becomes_empty = *bucketptr > 0 && n >= *bucketptr;
+  const int becomes_empty = bucket->bucket > 0 && n >= bucket->bucket;
-  *bucketptr -= n;
+  bucket->bucket -= n;
   return becomes_empty;
 }
 
@@ -170,7 +221,7 @@ int
 token_bucket_rw_dec_read(token_bucket_rw_t *bucket,
                       ssize_t n)
 {
-  return decrement_single_bucket(&bucket->read_bucket, n);
+  return token_bucket_raw_dec(&bucket->read_bucket, n);
 }
 
 /**
@@ -183,7 +234,7 @@ int
 token_bucket_rw_dec_write(token_bucket_rw_t *bucket,
                        ssize_t n)
 {
-  return decrement_single_bucket(&bucket->write_bucket, n);
+  return token_bucket_raw_dec(&bucket->write_bucket, n);
 }
 
 /**
@@ -192,9 +243,9 @@ token_bucket_rw_dec_write(token_bucket_rw_t *bucket,
  */
 void
 token_bucket_rw_dec(token_bucket_rw_t *bucket,
-                 ssize_t n_read, ssize_t n_written)
+                    ssize_t n_read, ssize_t n_written)
 {
   token_bucket_rw_dec_read(bucket, n_read);
-  token_bucket_rw_dec_read(bucket, n_written);
+  token_bucket_rw_dec_write(bucket, n_written);
 }
 

src/common/token_bucket.h

@@ -11,15 +11,64 @@
 
 #include "torint.h"
 
-typedef struct token_bucket_rw_t {
+/** Largest allowable burst value for a token buffer. */
+#define TOKEN_BUCKET_MAX_BURST INT32_MAX
+
+/** A generic token buffer configuration: determines the number of tokens
+ * added to the bucket in each time unit (the "rate"), and the maximum number
+ * of tokens in the bucket (the "burst") */
+typedef struct token_bucket_cfg_t {
   uint32_t rate;
   int32_t burst;
-  int32_t read_bucket;
+} token_bucket_cfg_t;
-  int32_t write_bucket;
-  uint32_t last_refilled_at_ts;
-} token_bucket_rw_t;
 
-#define TOKEN_BUCKET_RW_MAX_BURST INT32_MAX
+/** A raw token bucket, decoupled from its configuration and timestamp. */
+typedef struct token_bucket_raw_t {
+  int32_t bucket;
+} token_bucket_raw_t;
+
+/** A timestamp for a token bucket. The units of this timestamp are
+ * unspecified, but must match with the rate set in the token_bucket_cfg_t. */
+typedef struct token_bucket_timestamp_t {
+  uint32_t last_refilled_at;
+} token_bucket_timestamp_t;
+
+void token_bucket_cfg_init(token_bucket_cfg_t *cfg,
+                           uint32_t rate,
+                           uint32_t burst);
+
+void token_bucket_raw_adjust(token_bucket_raw_t *bucket,
+                             const token_bucket_cfg_t *cfg);
+
+void token_bucket_raw_reset(token_bucket_raw_t *bucket,
+                            token_bucket_timestamp_t *stamp,
+                            const token_bucket_cfg_t *cfg,
+                            uint32_t now);
+
+int token_bucket_raw_dec(token_bucket_raw_t *bucket,
+                         ssize_t n);
+
+int token_bucket_raw_refill_steps(token_bucket_raw_t *bucket,
+                                  const token_bucket_cfg_t *cfg,
+                                  const uint32_t elapsed_steps);
+
+static inline size_t token_bucket_raw_get(const token_bucket_raw_t *bucket);
+/** Return the current number of bytes set in a token bucket. */
+static inline size_t
+token_bucket_raw_get(const token_bucket_raw_t *bucket)
+{
+  return bucket->bucket >= 0 ? bucket->bucket : 0;
+}
+
+/** A convenience type containing all the pieces needed for a coupled
+ * read-bucket and write-bucket that have the same rate limit, and which use
+ * "timestamp units" (see compat_time.h) for their time. */
+typedef struct token_bucket_rw_t {
+  token_bucket_cfg_t cfg;
+  token_bucket_raw_t read_bucket;
+  token_bucket_raw_t write_bucket;
+  token_bucket_timestamp_t stamp;
+} token_bucket_rw_t;
 
 void token_bucket_rw_init(token_bucket_rw_t *bucket,
                        uint32_t rate,
@@ -50,8 +99,7 @@ static inline size_t token_bucket_rw_get_read(const token_bucket_rw_t *bucket);
 static inline size_t
 token_bucket_rw_get_read(const token_bucket_rw_t *bucket)
 {
-  const ssize_t b = bucket->read_bucket;
+  return token_bucket_raw_get(&bucket->read_bucket);
-  return b >= 0 ? b : 0;
 }
 
 static inline size_t token_bucket_rw_get_write(
@@ -59,8 +107,7 @@ static inline size_t token_bucket_rw_get_write(
 static inline size_t
 token_bucket_rw_get_write(const token_bucket_rw_t *bucket)
 {
-  const ssize_t b = bucket->write_bucket;
+  return token_bucket_raw_get(&bucket->write_bucket);
-  return b >= 0 ? b : 0;
 }
 
 #ifdef TOKEN_BUCKET_PRIVATE

src/test/test_bwmgt.c

@@ -25,19 +25,19 @@ test_bwmgt_token_buf_init(void *arg)
 
   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
   // Burst is correct
-  tt_uint_op(b.burst, OP_EQ, 64*KB);
+  tt_uint_op(b.cfg.burst, OP_EQ, 64*KB);
   // Rate is correct, within 1 percent.
   {
     uint32_t ticks_per_sec =
       (uint32_t) monotime_msec_to_approx_coarse_stamp_units(1000);
-    uint32_t rate_per_sec = (b.rate * ticks_per_sec / TICKS_PER_STEP);
+    uint32_t rate_per_sec = (b.cfg.rate * ticks_per_sec / TICKS_PER_STEP);
 
     tt_uint_op(rate_per_sec, OP_GT, 16*KB-160);
     tt_uint_op(rate_per_sec, OP_LT, 16*KB+160);
   }
   // Bucket starts out full:
-  tt_uint_op(b.last_refilled_at_ts, OP_EQ, START_TS);
+  tt_uint_op(b.stamp.last_refilled_at, OP_EQ, START_TS);
-  tt_int_op(b.read_bucket, OP_EQ, 64*KB);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 64*KB);
 
  done:
   ;
@@ -51,31 +51,31 @@ test_bwmgt_token_buf_adjust(void *arg)
 
   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
 
-  uint32_t rate_orig = b.rate;
+  uint32_t rate_orig = b.cfg.rate;
   // Increasing burst
   token_bucket_rw_adjust(&b, 16*KB, 128*KB);
-  tt_uint_op(b.rate, OP_EQ, rate_orig);
+  tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
-  tt_uint_op(b.read_bucket, OP_EQ, 64*KB);
+  tt_uint_op(b.read_bucket.bucket, OP_EQ, 64*KB);
-  tt_uint_op(b.burst, OP_EQ, 128*KB);
+  tt_uint_op(b.cfg.burst, OP_EQ, 128*KB);
 
   // Decreasing burst but staying above bucket
   token_bucket_rw_adjust(&b, 16*KB, 96*KB);
-  tt_uint_op(b.rate, OP_EQ, rate_orig);
+  tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
-  tt_uint_op(b.read_bucket, OP_EQ, 64*KB);
+  tt_uint_op(b.read_bucket.bucket, OP_EQ, 64*KB);
-  tt_uint_op(b.burst, OP_EQ, 96*KB);
+  tt_uint_op(b.cfg.burst, OP_EQ, 96*KB);
 
   // Decreasing burst below bucket,
   token_bucket_rw_adjust(&b, 16*KB, 48*KB);
-  tt_uint_op(b.rate, OP_EQ, rate_orig);
+  tt_uint_op(b.cfg.rate, OP_EQ, rate_orig);
-  tt_uint_op(b.read_bucket, OP_EQ, 48*KB);
+  tt_uint_op(b.read_bucket.bucket, OP_EQ, 48*KB);
-  tt_uint_op(b.burst, OP_EQ, 48*KB);
+  tt_uint_op(b.cfg.burst, OP_EQ, 48*KB);
 
   // Changing rate.
   token_bucket_rw_adjust(&b, 32*KB, 48*KB);
-  tt_uint_op(b.rate, OP_GE, rate_orig*2 - 10);
+  tt_uint_op(b.cfg.rate, OP_GE, rate_orig*2 - 10);
-  tt_uint_op(b.rate, OP_LE, rate_orig*2 + 10);
+  tt_uint_op(b.cfg.rate, OP_LE, rate_orig*2 + 10);
-  tt_uint_op(b.read_bucket, OP_EQ, 48*KB);
+  tt_uint_op(b.read_bucket.bucket, OP_EQ, 48*KB);
-  tt_uint_op(b.burst, OP_EQ, 48*KB);
+  tt_uint_op(b.cfg.burst, OP_EQ, 48*KB);
 
  done:
   ;
@@ -90,29 +90,29 @@ test_bwmgt_token_buf_dec(void *arg)
 
   // full-to-not-full.
   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, KB));
-  tt_int_op(b.read_bucket, OP_EQ, 63*KB);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 63*KB);
 
   // Full to almost-not-full
   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, 63*KB - 1));
-  tt_int_op(b.read_bucket, OP_EQ, 1);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 1);
 
   // almost-not-full to empty.
   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 1));
-  tt_int_op(b.read_bucket, OP_EQ, 0);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 0);
 
   // reset bucket, try full-to-empty
   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 64*KB));
-  tt_int_op(b.read_bucket, OP_EQ, 0);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 0);
 
   // reset bucket, try underflow.
   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
   tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, 64*KB + 1));
-  tt_int_op(b.read_bucket, OP_EQ, -1);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, -1);
 
   // A second underflow does not make the bucket empty.
   tt_int_op(0, OP_EQ, token_bucket_rw_dec_read(&b, 1000));
-  tt_int_op(b.read_bucket, OP_EQ, -1001);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, -1001);
 
  done:
   ;
@@ -125,68 +125,67 @@ test_bwmgt_token_buf_refill(void *arg)
   token_bucket_rw_t b;
   const uint32_t SEC =
     (uint32_t)monotime_msec_to_approx_coarse_stamp_units(1000);
-  printf("%d\n", (int)SEC);
   token_bucket_rw_init(&b, 16*KB, 64*KB, START_TS);
 
   /* Make the buffer much emptier, then let one second elapse. */
   token_bucket_rw_dec_read(&b, 48*KB);
-  tt_int_op(b.read_bucket, OP_EQ, 16*KB);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, 16*KB);
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC));
-  tt_int_op(b.read_bucket, OP_GT, 32*KB - 300);
+  tt_int_op(b.read_bucket.bucket, OP_GT, 32*KB - 300);
-  tt_int_op(b.read_bucket, OP_LT, 32*KB + 300);
+  tt_int_op(b.read_bucket.bucket, OP_LT, 32*KB + 300);
 
   /* Another half second. */
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2));
-  tt_int_op(b.read_bucket, OP_GT, 40*KB - 400);
+  tt_int_op(b.read_bucket.bucket, OP_GT, 40*KB - 400);
-  tt_int_op(b.read_bucket, OP_LT, 40*KB + 400);
+  tt_int_op(b.read_bucket.bucket, OP_LT, 40*KB + 400);
-  tt_uint_op(b.last_refilled_at_ts, OP_EQ, START_TS + SEC*3/2);
+  tt_uint_op(b.stamp.last_refilled_at, OP_EQ, START_TS + SEC*3/2);
 
   /* No time: nothing happens. */
   {
-    const uint32_t bucket_orig = b.read_bucket;
+    const uint32_t bucket_orig = b.read_bucket.bucket;
     tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2));
-    tt_int_op(b.read_bucket, OP_EQ, bucket_orig);
+    tt_int_op(b.read_bucket.bucket, OP_EQ, bucket_orig);
   }
 
   /* Another 30 seconds: fill the bucket. */
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*30));
-  tt_int_op(b.read_bucket, OP_EQ, b.burst);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
-  tt_uint_op(b.last_refilled_at_ts, OP_EQ, START_TS + SEC*3/2 + SEC*30);
+  tt_uint_op(b.stamp.last_refilled_at, OP_EQ, START_TS + SEC*3/2 + SEC*30);
 
   /* Another 30 seconds: nothing happens. */
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*60));
-  tt_int_op(b.read_bucket, OP_EQ, b.burst);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
-  tt_uint_op(b.last_refilled_at_ts, OP_EQ, START_TS + SEC*3/2 + SEC*60);
+  tt_uint_op(b.stamp.last_refilled_at, OP_EQ, START_TS + SEC*3/2 + SEC*60);
 
   /* Empty the bucket, let two seconds pass, and make sure that a refill is
    * noticed. */
-  tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, b.burst));
+  tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, b.cfg.burst));
-  tt_int_op(0, OP_EQ, b.read_bucket);
+  tt_int_op(0, OP_EQ, b.read_bucket.bucket);
   tt_int_op(1, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*61));
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*3/2 + SEC*62));
-  tt_int_op(b.read_bucket, OP_GT, 32*KB-400);
+  tt_int_op(b.read_bucket.bucket, OP_GT, 32*KB-400);
-  tt_int_op(b.read_bucket, OP_LT, 32*KB+400);
+  tt_int_op(b.read_bucket.bucket, OP_LT, 32*KB+400);
 
   /* Underflow the bucket, make sure we detect when it has tokens again. */
-  tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, b.read_bucket+16*KB));
+  tt_int_op(1, OP_EQ, token_bucket_rw_dec_read(&b, b.read_bucket.bucket+16*KB));
-  tt_int_op(-16*KB, OP_EQ, b.read_bucket);
+  tt_int_op(-16*KB, OP_EQ, b.read_bucket.bucket);
   // half a second passes...
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*64));
-  tt_int_op(b.read_bucket, OP_GT, -8*KB-300);
+  tt_int_op(b.read_bucket.bucket, OP_GT, -8*KB-300);
-  tt_int_op(b.read_bucket, OP_LT, -8*KB+300);
+  tt_int_op(b.read_bucket.bucket, OP_LT, -8*KB+300);
   // a second passes
   tt_int_op(1, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*65));
-  tt_int_op(b.read_bucket, OP_GT, 8*KB-400);
+  tt_int_op(b.read_bucket.bucket, OP_GT, 8*KB-400);
-  tt_int_op(b.read_bucket, OP_LT, 8*KB+400);
+  tt_int_op(b.read_bucket.bucket, OP_LT, 8*KB+400);
 
   // We step a second backwards, and nothing happens.
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, START_TS + SEC*64));
-  tt_int_op(b.read_bucket, OP_GT, 8*KB-400);
+  tt_int_op(b.read_bucket.bucket, OP_GT, 8*KB-400);
-  tt_int_op(b.read_bucket, OP_LT, 8*KB+400);
+  tt_int_op(b.read_bucket.bucket, OP_LT, 8*KB+400);
 
   // A ridiculous amount of time passes.
   tt_int_op(0, OP_EQ, token_bucket_rw_refill(&b, INT32_MAX));
-  tt_int_op(b.read_bucket, OP_EQ, b.burst);
+  tt_int_op(b.read_bucket.bucket, OP_EQ, b.cfg.burst);
 
  done:
   ;