diff --git a/lib/ngtcp2_rtb.c b/lib/ngtcp2_rtb.c
index 0f1d97f27d4964e66d00f018771de4084593266d..44792bff9290ba667875422a2e57b249a75049b8 100644
--- a/lib/ngtcp2_rtb.c
+++ b/lib/ngtcp2_rtb.c
@@ -241,6 +241,7 @@ void ngtcp2_rtb_init(ngtcp2_rtb *rtb, ngtcp2_pktns_id pktns_id,
rtb->cc_pkt_num = 0;
rtb->cc_bytes_in_flight = 0;
rtb->persistent_congestion_start_ts = UINT64_MAX;
+ rtb->num_lost_pkts = 0;
}
void ngtcp2_rtb_free(ngtcp2_rtb *rtb) {
@@ -322,6 +323,8 @@ static int rtb_on_pkt_lost(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
ent->flags |= NGTCP2_RTB_FLAG_LOST_RETRANSMITTED;
ent->lost_ts = ts;
+ ++rtb->num_lost_pkts;
+
ngtcp2_ksl_it_next(it);
return 0;
@@ -431,6 +434,8 @@ static int rtb_on_pkt_lost(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
ent->flags |= NGTCP2_RTB_FLAG_LOST_RETRANSMITTED;
ent->lost_ts = ts;
+ ++rtb->num_lost_pkts;
+
ngtcp2_ksl_it_next(it);
return 0;
@@ -720,12 +725,8 @@ ngtcp2_ssize ngtcp2_rtb_recv_ack(ngtcp2_rtb *rtb, const ngtcp2_ack *fr,
static int rtb_pkt_lost(ngtcp2_rtb *rtb, ngtcp2_conn_stat *cstat,
const ngtcp2_rtb_entry *ent, uint64_t loss_delay,
- ngtcp2_tstamp lost_send_time) {
+ ngtcp2_tstamp lost_send_time, uint64_t pkt_thres) {
ngtcp2_tstamp loss_time;
- uint64_t pkt_thres =
- rtb->cc_bytes_in_flight / cstat->max_udp_payload_size / 2;
-
- pkt_thres = ngtcp2_max(pkt_thres, NGTCP2_PKT_THRESHOLD);
if (ent->ts <= lost_send_time ||
rtb->largest_acked_tx_pkt_num >= ent->hd.pkt_num + (int64_t)pkt_thres) {
@@ -768,7 +769,10 @@ int ngtcp2_rtb_detect_lost_pkt(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
ngtcp2_duration loss_window, congestion_period;
ngtcp2_cc *cc = rtb->cc;
int rv;
+ uint64_t pkt_thres =
+ rtb->cc_bytes_in_flight / cstat->max_udp_payload_size / 2;
+ pkt_thres = ngtcp2_max(pkt_thres, NGTCP2_PKT_THRESHOLD);
cstat->loss_time[rtb->pktns_id] = UINT64_MAX;
loss_delay = compute_pkt_loss_delay(cstat);
lost_send_time = ts - loss_delay;
@@ -781,7 +785,7 @@ int ngtcp2_rtb_detect_lost_pkt(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
break;
}
- if (rtb_pkt_lost(rtb, cstat, ent, loss_delay, lost_send_time)) {
+ if (rtb_pkt_lost(rtb, cstat, ent, loss_delay, lost_send_time, pkt_thres)) {
/* All entries from ent are considered to be lost. */
latest_ts = oldest_ts = ent->ts;
last_lost_pkt_num = ent->hd.pkt_num;
@@ -840,12 +844,31 @@ int ngtcp2_rtb_detect_lost_pkt(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
}
}
- /* TODO Limit the number of LOST_RETRANSMITTED entries under maximum
- reordering threshold. */
+ ngtcp2_rtb_remove_excessive_lost_pkt(rtb, pkt_thres);
return 0;
}
+void ngtcp2_rtb_remove_excessive_lost_pkt(ngtcp2_rtb *rtb, size_t n) {
+ ngtcp2_ksl_it it = ngtcp2_ksl_end(&rtb->ents);
+ ngtcp2_rtb_entry *ent;
+
+ for (; rtb->num_lost_pkts > n;) {
+ assert(ngtcp2_ksl_it_end(&it));
+ ngtcp2_ksl_it_prev(&it);
+ ent = ngtcp2_ksl_it_get(&it);
+
+ assert(ent->flags & NGTCP2_RTB_FLAG_LOST_RETRANSMITTED);
+
+ ngtcp2_log_info(rtb->log, NGTCP2_LOG_EVENT_RCV,
+ "removing stale lost pkn=%" PRId64, ent->hd.pkt_num);
+
+ --rtb->num_lost_pkts;
+ ngtcp2_ksl_remove(&rtb->ents, &it, &ent->hd.pkt_num);
+ ngtcp2_rtb_entry_del(ent, rtb->mem);
+ }
+}
+
void ngtcp2_rtb_remove_expired_lost_pkt(ngtcp2_rtb *rtb, ngtcp2_duration pto,
ngtcp2_tstamp ts) {
ngtcp2_ksl_it it;
@@ -871,6 +894,7 @@ void ngtcp2_rtb_remove_expired_lost_pkt(ngtcp2_rtb *rtb, ngtcp2_duration pto,
ngtcp2_log_info(rtb->log, NGTCP2_LOG_EVENT_RCV,
"removing stale lost pkn=%" PRId64, ent->hd.pkt_num);
+ --rtb->num_lost_pkts;
ngtcp2_ksl_remove(&rtb->ents, &it, &ent->hd.pkt_num);
ngtcp2_rtb_entry_del(ent, rtb->mem);
@@ -909,6 +933,10 @@ static void rtb_on_pkt_lost2(ngtcp2_rtb *rtb, ngtcp2_frame_chain **pfrc,
}
if (!(ent->flags & NGTCP2_RTB_FLAG_PROBE)) {
+ if (ent->flags & NGTCP2_RTB_FLAG_LOST_RETRANSMITTED) {
+ --rtb->num_lost_pkts;
+ }
+
if (ent->flags & NGTCP2_RTB_FLAG_CRYPTO_TIMEOUT_RETRANSMITTED) {
ngtcp2_log_info(rtb->log, NGTCP2_LOG_EVENT_RCV,
"pkn=%" PRId64 " CRYPTO has already been retransmitted",
diff --git a/lib/ngtcp2_rtb.h b/lib/ngtcp2_rtb.h
index b9f350fa857accb081b62610259bab3aa60b7f04..d74b56f075b7603586d25aaaee2438bdff2523fa 100644
--- a/lib/ngtcp2_rtb.h
+++ b/lib/ngtcp2_rtb.h
@@ -259,6 +259,9 @@ typedef struct {
congestion evaluation is started. It happens roughly after
handshake is confirmed. */
ngtcp2_tstamp persistent_congestion_start_ts;
+ /* num_lost_pkts is the number entries in ents which has
+ NGTCP2_RTB_FLAG_LOST_RETRANSMITTED flag set. */
+ size_t num_lost_pkts;
} ngtcp2_rtb;
/*
@@ -368,4 +371,10 @@ int ngtcp2_rtb_empty(ngtcp2_rtb *rtb);
*/
void ngtcp2_rtb_reset_cc_state(ngtcp2_rtb *rtb, int64_t cc_pkt_num);
+/*
+ * ngtcp2_rtb_remove_expired_lost_pkt ensures that the number of lost
+ * packets at most |n|.
+ */
+void ngtcp2_rtb_remove_excessive_lost_pkt(ngtcp2_rtb *rtb, size_t n);
+
#endif /* NGTCP2_RTB_H */
diff --git a/tests/main.c b/tests/main.c
index 3ac72fc1c92a86ce46adf71c233bc6ac949b00b1..1336eb82ce0c38bbea5f0804b1ca0298e05dae5d 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -169,6 +169,8 @@ int main() {
!CU_add_test(pSuite, "rtb_lost_pkt_ts", test_ngtcp2_rtb_lost_pkt_ts) ||
!CU_add_test(pSuite, "rtb_remove_expired_lost_pkt",
test_ngtcp2_rtb_remove_expired_lost_pkt) ||
+ !CU_add_test(pSuite, "rtb_remove_excessive_lost_pkt",
+ test_ngtcp2_rtb_remove_excessive_lost_pkt) ||
!CU_add_test(pSuite, "idtr_open", test_ngtcp2_idtr_open) ||
!CU_add_test(pSuite, "ringbuf_push_front",
test_ngtcp2_ringbuf_push_front) ||
diff --git a/tests/ngtcp2_rtb_test.c b/tests/ngtcp2_rtb_test.c
index 3e303da36d37ec19f287b46af316bef9ebf8ab97..3f6c4f132d86128018c9d0769d28bcdd2a80181a 100644
--- a/tests/ngtcp2_rtb_test.c
+++ b/tests/ngtcp2_rtb_test.c
@@ -367,3 +367,45 @@ void test_ngtcp2_rtb_remove_expired_lost_pkt(void) {
ngtcp2_cc_reno_cc_free(&cc, mem);
ngtcp2_strm_free(&crypto);
}
+
+void test_ngtcp2_rtb_remove_excessive_lost_pkt(void) {
+ ngtcp2_rtb rtb;
+ const ngtcp2_pktns_id pktns_id = NGTCP2_PKTNS_ID_APP;
+ ngtcp2_strm crypto;
+ ngtcp2_log log;
+ const ngtcp2_mem *mem = ngtcp2_mem_default();
+ ngtcp2_cc cc;
+ ngtcp2_rst rst;
+ ngtcp2_conn_stat cstat;
+ ngtcp2_ksl_it it;
+ ngtcp2_rtb_entry *ent;
+ size_t i;
+
+ ngtcp2_strm_init(&crypto, 0, NGTCP2_STRM_FLAG_NONE, 0, 0, NULL, mem);
+ ngtcp2_log_init(&log, NULL, NULL, 0, NULL);
+
+ conn_stat_init(&cstat);
+ ngtcp2_rst_init(&rst);
+ ngtcp2_cc_reno_cc_init(&cc, &log, mem);
+ ngtcp2_rtb_init(&rtb, pktns_id, &crypto, &rst, &cc, &log, NULL, mem);
+
+ add_rtb_entry_range(&rtb, 0, 7, &cstat, mem);
+
+ it = ngtcp2_ksl_end(&rtb.ents);
+
+ for (i = 0; i < 5; ++i) {
+ ngtcp2_ksl_it_prev(&it);
+ ent = ngtcp2_ksl_it_get(&it);
+ ent->flags |= NGTCP2_RTB_FLAG_LOST_RETRANSMITTED;
+ ent->lost_ts = 16777217;
+ ++rtb.num_lost_pkts;
+ }
+
+ ngtcp2_rtb_remove_excessive_lost_pkt(&rtb, 2);
+
+ CU_ASSERT(4 == ngtcp2_ksl_len(&rtb.ents));
+
+ ngtcp2_rtb_free(&rtb);
+ ngtcp2_cc_reno_cc_free(&cc, mem);
+ ngtcp2_strm_free(&crypto);
+}
diff --git a/tests/ngtcp2_rtb_test.h b/tests/ngtcp2_rtb_test.h
index c9bf2f9671973f3fbd34939a9922809896756ac1..f880e1eb786cbf748c27c570725ef3e5951fe55e 100644
--- a/tests/ngtcp2_rtb_test.h
+++ b/tests/ngtcp2_rtb_test.h
@@ -33,5 +33,6 @@ void test_ngtcp2_rtb_add(void);
void test_ngtcp2_rtb_recv_ack(void);
void test_ngtcp2_rtb_lost_pkt_ts(void);
void test_ngtcp2_rtb_remove_expired_lost_pkt(void);
+void test_ngtcp2_rtb_remove_excessive_lost_pkt(void);
#endif /* NGTCP2_RTB_TEST_H */