commit 996409c9c4691fbb6cccaba11ceb84c1a5ef7906 Author: David Goulet dgoulet@torproject.org Date: Tue Oct 19 15:07:11 2021 -0400
test: Add unit tests for DNS timeout overload state
Signed-off-by: David Goulet dgoulet@torproject.org --- src/test/test_stats.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+)
diff --git a/src/test/test_stats.c b/src/test/test_stats.c index 081ae22cd5..3b9a192c75 100644 --- a/src/test/test_stats.c +++ b/src/test/test_stats.c @@ -51,6 +51,8 @@ #include "feature/stats/bw_array_st.h" #include "feature/relay/router.h"
+#include "event2/dns.h" + /** Run unit tests for some stats code. */ static void test_stats(void *arg) @@ -865,6 +867,81 @@ test_overload_stats(void *arg) tor_free(stats_str); }
+/** Test the overload stats logic. */ +static void +test_overload_dns_timeout(void *arg) +{ + char *stats_str = NULL; + (void) arg; + + /* Lets simulate a series of timeouts but below our default 1% threshold. */ + + for (int i = 0; i < 1000; i++) { + /* This should trigger 9 timeouts which is just below 1% (10) */ + if (i > 0 && !(i % 100)) { + rep_hist_note_dns_query(0, DNS_ERR_TIMEOUT); + } else { + rep_hist_note_dns_query(0, DNS_ERR_NONE); + } + } + + /* No overload yet. */ + stats_str = rep_hist_get_overload_general_line(); + tt_assert(!stats_str); + + /* Move it 10 minutes in the future and see if we get a general overload. */ + update_approx_time(approx_time() + (10 * 60)); + + /* This query should NOT trigger the general overload because we are below + * our default of 1%. */ + rep_hist_note_dns_query(0, DNS_ERR_NONE); + stats_str = rep_hist_get_overload_general_line(); + tt_assert(!stats_str); + + /* We'll now go above our 1% threshold. */ + for (int i = 0; i < 1000; i++) { + /* This should trigger 10 timeouts which is our threshold of 1% (10) */ + if (!(i % 10)) { + rep_hist_note_dns_query(0, DNS_ERR_TIMEOUT); + } else { + rep_hist_note_dns_query(0, DNS_ERR_NONE); + } + } + + /* Move it 10 minutes in the future and see if we get a general overload. */ + update_approx_time(approx_time() + (10 * 60)); + + /* This query should trigger the general overload because we are above 1%. */ + rep_hist_note_dns_query(0, DNS_ERR_NONE); + stats_str = rep_hist_get_overload_general_line(); + tt_assert(stats_str); + tor_free(stats_str); + + /* Move 72h in the future, we should NOT get an overload anymore. */ + update_approx_time(approx_time() + (72 * 3600)); + + stats_str = rep_hist_get_overload_general_line(); + tt_assert(!stats_str); + + /* This query should NOT trigger the general overload. */ + rep_hist_note_dns_query(0, DNS_ERR_TIMEOUT); + stats_str = rep_hist_get_overload_general_line(); + tt_assert(!stats_str); + + /* Move it 10 minutes in the future and see if we get a general overload. We + * have now 100% of requests timing out. */ + update_approx_time(approx_time() + (10 * 60)); + + /* This query should trigger the general overload with 50% of timeouts. */ + rep_hist_note_dns_query(0, DNS_ERR_NONE); + stats_str = rep_hist_get_overload_general_line(); + tt_assert(stats_str); + tor_free(stats_str); + + done: + tor_free(stats_str); +} + #define ENT(name) \ { #name, test_ ## name , 0, NULL, NULL } #define FORK(name) \ @@ -881,6 +958,7 @@ struct testcase_t stats_tests[] = { FORK(rephist_v3_onions), FORK(load_stats_file), FORK(overload_stats), + FORK(overload_dns_timeout),
END_OF_TESTCASES };