[tor-commits] [tor/master] token-bucket: Implement a single counter object
asn at torproject.org
asn at torproject.org
Tue Jun 11 11:07:05 UTC 2019
commit 7cf9d54e6d7a08f169a27f7d76731e61ebe63fb0
Author: David Goulet <dgoulet at torproject.org>
Date: Wed May 29 11:34:07 2019 -0400
token-bucket: Implement a single counter object
Closes #30687.
Signed-off-by: David Goulet <dgoulet at torproject.org>
---
changes/ticket30687 | 3 +
src/lib/evloop/token_bucket.c | 52 +++++++++++++++
src/lib/evloop/token_bucket.h | 29 ++++++++
src/test/include.am | 1 +
src/test/test.c | 1 +
src/test/test.h | 1 +
src/test/test_token_bucket.c | 152 ++++++++++++++++++++++++++++++++++++++++++
7 files changed, 239 insertions(+)
diff --git a/changes/ticket30687 b/changes/ticket30687
new file mode 100644
index 000000000..c3124eb64
--- /dev/null
+++ b/changes/ticket30687
@@ -0,0 +1,3 @@
+ o Minor feature (token bucket):
+ - Implement a generic token bucket that uses a single counter. This will be
+ useful for the anti-DoS onion service work. Closes ticket 30687.
diff --git a/src/lib/evloop/token_bucket.c b/src/lib/evloop/token_bucket.c
index ee6d631e3..ec62d1b01 100644
--- a/src/lib/evloop/token_bucket.c
+++ b/src/lib/evloop/token_bucket.c
@@ -256,3 +256,55 @@ token_bucket_rw_dec(token_bucket_rw_t *bucket,
flags |= TB_WRITE;
return flags;
}
+
+/** Initialize a token bucket in <b>bucket</b>, set up to allow <b>rate</b>
+ * per second, with a maximum burst of <b>burst</b>. The bucket is created
+ * such that <b>now_ts</b> is the current timestamp. The bucket starts out
+ * full. */
+void
+token_bucket_ctr_init(token_bucket_ctr_t *bucket, uint32_t rate,
+ uint32_t burst, uint32_t now_ts)
+{
+ memset(bucket, 0, sizeof(token_bucket_ctr_t));
+ token_bucket_ctr_adjust(bucket, rate, burst);
+ token_bucket_ctr_reset(bucket, now_ts);
+}
+
+/** Change the configured rate and burst of the given token bucket object in
+ * <b>bucket</b>. */
+void
+token_bucket_ctr_adjust(token_bucket_ctr_t *bucket, uint32_t rate,
+ uint32_t burst)
+{
+ token_bucket_cfg_init(&bucket->cfg, rate, burst);
+ token_bucket_raw_adjust(&bucket->counter, &bucket->cfg);
+}
+
+/** Reset <b>bucket</b> to be full, as of timestamp <b>now_ts</b>. */
+void
+token_bucket_ctr_reset(token_bucket_ctr_t *bucket, uint32_t now_ts)
+{
+ token_bucket_raw_reset(&bucket->counter, &bucket->cfg);
+ bucket->last_refilled_at_timestamp = now_ts;
+}
+
+/** Refill <b>bucket</b> as appropriate, given that the current timestamp is
+ * <b>now_ts</b>. */
+void
+token_bucket_ctr_refill(token_bucket_ctr_t *bucket, uint32_t now_ts)
+{
+ const uint32_t elapsed_ticks =
+ (now_ts - bucket->last_refilled_at_timestamp);
+ 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,
+ * Windows.). We accept up to a 5 minute jump backwards as
+ * "unremarkable".
+ */
+ return;
+ }
+
+ token_bucket_raw_refill_steps(&bucket->counter, &bucket->cfg,
+ elapsed_ticks);
+ bucket->last_refilled_at_timestamp = now_ts;
+}
diff --git a/src/lib/evloop/token_bucket.h b/src/lib/evloop/token_bucket.h
index 9398d2baa..35b4246b1 100644
--- a/src/lib/evloop/token_bucket.h
+++ b/src/lib/evloop/token_bucket.h
@@ -103,6 +103,35 @@ token_bucket_rw_get_write(const token_bucket_rw_t *bucket)
return token_bucket_raw_get(&bucket->write_bucket);
}
+/**
+ * A specialized bucket containing a single counter.
+ */
+
+typedef struct token_bucket_ctr_t {
+ token_bucket_cfg_t cfg;
+ token_bucket_raw_t counter;
+ uint32_t last_refilled_at_timestamp;
+} token_bucket_ctr_t;
+
+void token_bucket_ctr_init(token_bucket_ctr_t *bucket, uint32_t rate,
+ uint32_t burst, uint32_t now_ts);
+void token_bucket_ctr_adjust(token_bucket_ctr_t *bucket, uint32_t rate,
+ uint32_t burst);
+void token_bucket_ctr_reset(token_bucket_ctr_t *bucket, uint32_t now_ts);
+void token_bucket_ctr_refill(token_bucket_ctr_t *bucket, uint32_t now_ts);
+
+static inline bool
+token_bucket_ctr_dec(token_bucket_ctr_t *bucket, ssize_t n)
+{
+ return token_bucket_raw_dec(&bucket->counter, n);
+}
+
+static inline size_t
+token_bucket_ctr_get(const token_bucket_ctr_t *bucket)
+{
+ return token_bucket_raw_get(&bucket->counter);
+}
+
#ifdef TOKEN_BUCKET_PRIVATE
/* To avoid making the rates too small, we consider units of "steps",
diff --git a/src/test/include.am b/src/test/include.am
index 85f9c9f88..624bca66d 100644
--- a/src/test/include.am
+++ b/src/test/include.am
@@ -193,6 +193,7 @@ src_test_test_SOURCES += \
src/test/test_status.c \
src/test/test_storagedir.c \
src/test/test_threads.c \
+ src/test/test_token_bucket.c \
src/test/test_tortls.c \
src/test/test_util.c \
src/test/test_util_format.c \
diff --git a/src/test/test.c b/src/test/test.c
index cac98dd83..cc0853170 100644
--- a/src/test/test.c
+++ b/src/test/test.c
@@ -916,6 +916,7 @@ struct testgroup_t testgroups[] = {
{ "socks/", socks_tests },
{ "status/" , status_tests },
{ "storagedir/", storagedir_tests },
+ { "token_bucket/", token_bucket_tests },
{ "tortls/", tortls_tests },
#ifndef ENABLE_NSS
{ "tortls/openssl/", tortls_openssl_tests },
diff --git a/src/test/test.h b/src/test/test.h
index 167fd090a..85e8b07ff 100644
--- a/src/test/test.h
+++ b/src/test/test.h
@@ -272,6 +272,7 @@ extern struct testcase_t sr_tests[];
extern struct testcase_t status_tests[];
extern struct testcase_t storagedir_tests[];
extern struct testcase_t thread_tests[];
+extern struct testcase_t token_bucket_tests[];
extern struct testcase_t tortls_openssl_tests[];
extern struct testcase_t tortls_tests[];
extern struct testcase_t util_format_tests[];
diff --git a/src/test/test_token_bucket.c b/src/test/test_token_bucket.c
new file mode 100644
index 000000000..d3ce59138
--- /dev/null
+++ b/src/test/test_token_bucket.c
@@ -0,0 +1,152 @@
+/* Copyright (c) 2018-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file test_bwmgt.c
+ * \brief tests for bandwidth management / token bucket functions
+ */
+
+#define TOKEN_BUCKET_PRIVATE
+
+#include "core/or/or.h"
+#include "test/test.h"
+
+#include "lib/evloop/token_bucket.h"
+
+// an imaginary time, in timestamp units. Chosen so it will roll over.
+static const uint32_t START_TS = UINT32_MAX - 1000;
+static const uint32_t RATE = 10;
+static const uint32_t BURST = 50;
+
+static void
+test_token_bucket_ctr_init(void *arg)
+{
+ (void) arg;
+ token_bucket_ctr_t tb;
+
+ token_bucket_ctr_init(&tb, RATE, BURST, START_TS);
+ tt_uint_op(tb.cfg.rate, OP_EQ, RATE);
+ tt_uint_op(tb.cfg.burst, OP_EQ, BURST);
+ tt_uint_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS);
+ tt_int_op(tb.counter.bucket, OP_EQ, BURST);
+
+ done:
+ ;
+}
+
+static void
+test_token_bucket_ctr_adjust(void *arg)
+{
+ (void) arg;
+ token_bucket_ctr_t tb;
+
+ token_bucket_ctr_init(&tb, RATE, BURST, START_TS);
+
+ /* Increase burst. */
+ token_bucket_ctr_adjust(&tb, RATE, BURST * 2);
+ tt_uint_op(tb.cfg.rate, OP_EQ, RATE);
+ tt_uint_op(tb.counter.bucket, OP_EQ, BURST);
+ tt_uint_op(tb.cfg.burst, OP_EQ, BURST * 2);
+
+ /* Decrease burst but still above bucket value. */
+ token_bucket_ctr_adjust(&tb, RATE, BURST + 10);
+ tt_uint_op(tb.cfg.rate, OP_EQ, RATE);
+ tt_uint_op(tb.counter.bucket, OP_EQ, BURST);
+ tt_uint_op(tb.cfg.burst, OP_EQ, BURST + 10);
+
+ /* Decrease burst below bucket value. */
+ token_bucket_ctr_adjust(&tb, RATE, BURST - 1);
+ tt_uint_op(tb.cfg.rate, OP_EQ, RATE);
+ tt_uint_op(tb.counter.bucket, OP_EQ, BURST - 1);
+ tt_uint_op(tb.cfg.burst, OP_EQ, BURST - 1);
+
+ /* Change rate. */
+ token_bucket_ctr_adjust(&tb, RATE * 2, BURST);
+ tt_uint_op(tb.cfg.rate, OP_EQ, RATE * 2);
+ tt_uint_op(tb.counter.bucket, OP_EQ, BURST - 1);
+ tt_uint_op(tb.cfg.burst, OP_EQ, BURST);
+
+ done:
+ ;
+}
+
+static void
+test_token_bucket_ctr_dec(void *arg)
+{
+ (void) arg;
+ token_bucket_ctr_t tb;
+
+ token_bucket_ctr_init(&tb, RATE, BURST, START_TS);
+
+ /* Simple decrement by one. */
+ tt_uint_op(0, OP_EQ, token_bucket_ctr_dec(&tb, 1));
+ tt_uint_op(tb.counter.bucket, OP_EQ, BURST - 1);
+
+ /* Down to 0. Becomes empty. */
+ tt_uint_op(true, OP_EQ, token_bucket_ctr_dec(&tb, BURST - 1));
+ tt_uint_op(tb.counter.bucket, OP_EQ, 0);
+
+ /* Reset and try to underflow. */
+ token_bucket_ctr_init(&tb, RATE, BURST, START_TS);
+ tt_uint_op(true, OP_EQ, token_bucket_ctr_dec(&tb, BURST + 1));
+ tt_int_op(tb.counter.bucket, OP_EQ, -1);
+
+ /* Keep underflowing shouldn't flag the bucket as empty. */
+ tt_uint_op(false, OP_EQ, token_bucket_ctr_dec(&tb, BURST));
+ tt_int_op(tb.counter.bucket, OP_EQ, (int32_t) ((BURST + 1) * -1));
+
+ done:
+ ;
+}
+
+static void
+test_token_bucket_ctr_refill(void *arg)
+{
+ (void) arg;
+ token_bucket_ctr_t tb;
+
+ token_bucket_ctr_init(&tb, RATE, BURST, START_TS);
+
+ /* Reduce of half the bucket and let a single second go before refill. */
+ token_bucket_ctr_dec(&tb, BURST / 2);
+ tt_int_op(tb.counter.bucket, OP_EQ, BURST / 2);
+ token_bucket_ctr_refill(&tb, START_TS + 1);
+ tt_int_op(tb.counter.bucket, OP_EQ, (BURST / 2) + RATE);
+ tt_int_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS + 1);
+
+ /* No time change, nothing should move. */
+ token_bucket_ctr_refill(&tb, START_TS + 1);
+ tt_int_op(tb.counter.bucket, OP_EQ, (BURST / 2) + RATE);
+ tt_int_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS + 1);
+
+ /* Add 99 seconds, bucket should be back to a full BURST. */
+ token_bucket_ctr_refill(&tb, START_TS + 99);
+ tt_int_op(tb.counter.bucket, OP_EQ, BURST);
+ tt_int_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS + 99);
+
+ /* Empty bucket at once. */
+ token_bucket_ctr_dec(&tb, BURST);
+ tt_int_op(tb.counter.bucket, OP_EQ, 0);
+ /* On second passes. */
+ token_bucket_ctr_refill(&tb, START_TS + 100);
+ tt_int_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS + 100);
+ tt_int_op(tb.counter.bucket, OP_EQ, RATE);
+ /* A second second passes. */
+ token_bucket_ctr_refill(&tb, START_TS + 101);
+ tt_int_op(tb.last_refilled_at_timestamp, OP_EQ, START_TS + 101);
+ tt_int_op(tb.counter.bucket, OP_EQ, RATE * 2);
+
+ done:
+ ;
+}
+
+#define TOKEN_BUCKET(name) \
+ { #name, test_token_bucket_ ## name , 0, NULL, NULL }
+
+struct testcase_t token_bucket_tests[] = {
+ TOKEN_BUCKET(ctr_init),
+ TOKEN_BUCKET(ctr_adjust),
+ TOKEN_BUCKET(ctr_dec),
+ TOKEN_BUCKET(ctr_refill),
+ END_OF_TESTCASES
+};
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