From ea0207e2c5b784ef7345c1b1a10b78e42774cad6 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Thu, 23 May 2019 16:27:28 +0900
Subject: [PATCH] Add function to cancel expired ACK delay timer
---
doc/programmers-guide.rst | 1 +
examples/client.cc | 1 +
examples/server.cc | 1 +
lib/includes/ngtcp2/ngtcp2.h | 11 +++++++++++
lib/ngtcp2_acktr.c | 6 +++---
lib/ngtcp2_acktr.h | 3 +++
lib/ngtcp2_conn.c | 27 ++++++++++++++++++++++-----
7 files changed, 42 insertions(+), 8 deletions(-)
diff --git a/doc/programmers-guide.rst b/doc/programmers-guide.rst
index 3d504064..8a4bed47 100644
--- a/doc/programmers-guide.rst
+++ b/doc/programmers-guide.rst
@@ -271,6 +271,7 @@ timestamp is equal to or larger than the value returned from
(or `ngtcp2_conn_write_handshake()` if handshake has not completed
yet). If the current timestamp is equal to or larger than the value
returned from `ngtcp2_conn_ack_delay_expiry()`, it has to call
+`ngtcp2_conn_cancel_expired_ack_delay_timer()` and
`ngtcp2_conn_write_pkt()` (or `ngtcp2_conn_write_handshake()` if
handshake has not completed yet). After calling these functions, new
expiry will be set. The application should call
diff --git a/examples/client.cc b/examples/client.cc
index 6041c1a2..7cf29c3c 100644
--- a/examples/client.cc
+++ b/examples/client.cc
@@ -361,6 +361,7 @@ void retransmitcb(struct ev_loop *loop, ev_timer *w, int revents) {
}
if (ngtcp2_conn_ack_delay_expiry(conn) <= now) {
+ ngtcp2_conn_cancel_expired_ack_delay_timer(conn, now);
rv = c->on_write();
if (rv != 0) {
goto fail;
diff --git a/examples/server.cc b/examples/server.cc
index 4556adb1..66099927 100644
--- a/examples/server.cc
+++ b/examples/server.cc
@@ -835,6 +835,7 @@ void retransmitcb(struct ev_loop *loop, ev_timer *w, int revents) {
if (!config.quiet) {
std::cerr << "Delayed ACK timer expired" << std::endl;
}
+ ngtcp2_conn_cancel_expired_ack_delay_timer(conn, now);
rv = h->on_write();
switch (rv) {
case 0:
diff --git a/lib/includes/ngtcp2/ngtcp2.h b/lib/includes/ngtcp2/ngtcp2.h
index 9428fd5f..8b6bb4c9 100644
--- a/lib/includes/ngtcp2/ngtcp2.h
+++ b/lib/includes/ngtcp2/ngtcp2.h
@@ -2030,6 +2030,7 @@ ngtcp2_conn_loss_detection_expiry(ngtcp2_conn *conn);
*
* `ngtcp2_conn_ack_delay_expiry` returns the expiry time point of
* delayed protected ACK. Application should call
+ * ngtcp2_conn_cancel_expired_ack_delay_timer() and
* `ngtcp2_conn_write_pkt` (or `ngtcp2_conn_write_handshake` if
* handshake has not finished yet) when it expires. It returns
* UINT64_MAX if there is no expiry.
@@ -2046,6 +2047,16 @@ NGTCP2_EXTERN ngtcp2_tstamp ngtcp2_conn_ack_delay_expiry(ngtcp2_conn *conn);
*/
NGTCP2_EXTERN ngtcp2_tstamp ngtcp2_conn_get_expiry(ngtcp2_conn *conn);
+/**
+ * @function
+ *
+ * `ngtcp2_conn_cancel_expired_ack_delay_timer` stops expired ACK
+ * delay timer. |ts| is the current time. This function must be
+ * called when ngtcp2_conn_ack_delay_expiry() <= ts.
+ */
+NGTCP2_EXTERN void ngtcp2_conn_cancel_expired_ack_delay_timer(ngtcp2_conn *conn,
+ ngtcp2_tstamp ts);
+
/**
* @function
*
diff --git a/lib/ngtcp2_acktr.c b/lib/ngtcp2_acktr.c
index e7403db6..494e4cd6 100644
--- a/lib/ngtcp2_acktr.c
+++ b/lib/ngtcp2_acktr.c
@@ -316,15 +316,15 @@ void ngtcp2_acktr_recv_ack(ngtcp2_acktr *acktr, const ngtcp2_ack *fr) {
void ngtcp2_acktr_commit_ack(ngtcp2_acktr *acktr) {
acktr->flags &= (uint16_t) ~(NGTCP2_ACKTR_FLAG_ACTIVE_ACK |
- NGTCP2_ACKTR_FLAG_IMMEDIATE_ACK);
+ NGTCP2_ACKTR_FLAG_IMMEDIATE_ACK |
+ NGTCP2_ACKTR_FLAG_CANCEL_TIMER);
acktr->first_unacked_ts = UINT64_MAX;
acktr->rx_npkt = 0;
}
int ngtcp2_acktr_require_active_ack(ngtcp2_acktr *acktr, uint64_t max_ack_delay,
ngtcp2_tstamp ts) {
- return (acktr->flags & NGTCP2_ACKTR_FLAG_ACTIVE_ACK) &&
- acktr->first_unacked_ts <= ts - max_ack_delay;
+ return acktr->first_unacked_ts <= ts - max_ack_delay;
}
void ngtcp2_acktr_immediate_ack(ngtcp2_acktr *acktr) {
diff --git a/lib/ngtcp2_acktr.h b/lib/ngtcp2_acktr.h
index 35e00d76..19864203 100644
--- a/lib/ngtcp2_acktr.h
+++ b/lib/ngtcp2_acktr.h
@@ -108,6 +108,9 @@ typedef enum {
acknowledgement for ACK which acknowledges the last handshake
packet from client (which contains TLSv1.3 Finished message). */
NGTCP2_ACKTR_FLAG_ACK_FINISHED_ACK = 0x80,
+ /* NGTCP2_ACKTR_FLAG_CANCEL_TIMER is set when ACK delay timer is
+ expired and canceled. */
+ NGTCP2_ACKTR_FLAG_CANCEL_TIMER = 0x0100,
} ngtcp2_acktr_flag;
/*
diff --git a/lib/ngtcp2_conn.c b/lib/ngtcp2_conn.c
index cafd051d..ba886462 100644
--- a/lib/ngtcp2_conn.c
+++ b/lib/ngtcp2_conn.c
@@ -1754,8 +1754,7 @@ static ssize_t conn_write_handshake_ack_pkt(ngtcp2_conn *conn, uint8_t *dest,
* Initial and Handshake packet.
*/
static ssize_t conn_write_handshake_ack_pkts(ngtcp2_conn *conn, uint8_t *dest,
- size_t destlen,
- ngtcp2_tstamp ts) {
+ size_t destlen, ngtcp2_tstamp ts) {
ssize_t res = 0, nwrite = 0;
int require_padding;
@@ -7511,15 +7510,18 @@ ngtcp2_tstamp ngtcp2_conn_ack_delay_expiry(ngtcp2_conn *conn) {
ngtcp2_acktr *acktr = &conn->pktns.acktr;
ngtcp2_tstamp ts = UINT64_MAX, t;
- if (in_acktr->first_unacked_ts != UINT64_MAX) {
+ if (!(in_acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) &&
+ in_acktr->first_unacked_ts != UINT64_MAX) {
t = in_acktr->first_unacked_ts + NGTCP2_HS_ACK_DELAY;
ts = ngtcp2_min(ts, t);
}
- if (hs_acktr->first_unacked_ts != UINT64_MAX) {
+ if (!(hs_acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) &&
+ hs_acktr->first_unacked_ts != UINT64_MAX) {
t = hs_acktr->first_unacked_ts + NGTCP2_HS_ACK_DELAY;
ts = ngtcp2_min(ts, t);
}
- if (acktr->first_unacked_ts != UINT64_MAX) {
+ if (!(acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) &&
+ acktr->first_unacked_ts != UINT64_MAX) {
t = acktr->first_unacked_ts + conn_compute_ack_delay(conn);
ts = ngtcp2_min(ts, t);
}
@@ -7532,6 +7534,21 @@ ngtcp2_tstamp ngtcp2_conn_get_expiry(ngtcp2_conn *conn) {
return ngtcp2_min(t1, t2);
}
+static void acktr_cancel_expired_ack_delay_timer(ngtcp2_acktr *acktr,
+ ngtcp2_tstamp ts) {
+ if (!(acktr->flags & NGTCP2_ACKTR_FLAG_CANCEL_TIMER) &&
+ acktr->first_unacked_ts <= ts) {
+ acktr->flags |= NGTCP2_ACKTR_FLAG_CANCEL_TIMER;
+ }
+}
+
+void ngtcp2_conn_cancel_expired_ack_delay_timer(ngtcp2_conn *conn,
+ ngtcp2_tstamp ts) {
+ acktr_cancel_expired_ack_delay_timer(&conn->in_pktns.acktr, ts);
+ acktr_cancel_expired_ack_delay_timer(&conn->hs_pktns.acktr, ts);
+ acktr_cancel_expired_ack_delay_timer(&conn->pktns.acktr, ts);
+}
+
/*
* settings_copy_from_transport_params translates
* ngtcp2_transport_params to ngtcp2_settings.
--
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