MINOR: quic: Add correct ack delay values to ACK frames

A ->time_received new member is added to quic_rx_packet to store the time the
packet are received. ->largest_time_received is added the the packet number
space structure to store this timestamp for the packet with a new largest
packet number to be acknowledged. QUIC_FL_PKTNS_NEW_LARGEST_PN new flag is
added to mark a packet number space as having to acknowledged a packet wih a
new largest packet number. In this case, the packet number space ack delay
must be recalculated.
Add quic_compute_ack_delay_us() function to compute the ack delay from the value
of the time a packet was received. Used only when a packet with a new largest
packet number.

diff --git a/include/haproxy/xprt_quic-t.h b/include/haproxy/xprt_quic-t.h
index 504294f1210d92af04b931b90fb9de0db541785e..4db01fc99797c3e213ccf3996d6faef5e59d893b 100644 (file)
--- a/include/haproxy/xprt_quic-t.h
+++ b/include/haproxy/xprt_quic-t.h
@@ -395,6 +395,10 @@ struct quic_arngs {
 #define QUIC_FL_PKTNS_ACK_REQUIRED  (1UL << 1)
 /* Flag the packet number space as needing probing */
 #define QUIC_FL_PKTNS_PROBE_NEEDED  (1UL << 2)
+/* Flag the packet number space as having received a packet with a new largest
+ * packet number, to be acknowledege
+ */
+#define QUIC_FL_PKTNS_NEW_LARGEST_PN (1UL << 3)
 
 /* The maximum number of dgrams which may be sent upon PTO expirations. */
 #define QUIC_MAX_NB_PTO_DGRAMS         2
@@ -416,6 +420,8 @@ struct quic_pktns {
                unsigned int pto_probe;
                /* In flight bytes for this packet number space. */
                size_t in_flight;
+               /* The acknowledgement delay of the packet with the largest packet number */
+               uint64_t ack_delay;
        } tx;
        struct {
                /* Largest packet number */
@@ -424,6 +430,8 @@ struct quic_pktns {
                int64_t largest_acked_pn;
                struct quic_arngs arngs;
                unsigned int nb_aepkts_since_last_ack;
+               /* The time the packet with the largest packet number was received */
+               uint64_t largest_time_received;
        } rx;
        unsigned int flags;
 };
@@ -483,6 +491,7 @@ struct quic_rx_packet {
        /* Source address of this packet. */
        struct sockaddr_storage saddr;
        unsigned int flags;
+       unsigned int time_received;
 };
 
 /* QUIC datagram handler */

diff --git a/include/haproxy/xprt_quic.h b/include/haproxy/xprt_quic.h
index 6457fa4b1e91224e7bf9fdc9b022c716e0fa3b04..2c98ed602878c97b18b31290c6f6f616f57a7ab0 100644 (file)
--- a/include/haproxy/xprt_quic.h
+++ b/include/haproxy/xprt_quic.h
@@ -477,6 +477,15 @@ static inline unsigned int quic_ack_delay_ms(struct quic_ack *ack_frm,
        return (ack_frm->ack_delay << conn->tx.params.ack_delay_exponent) / 1000;
 }
 
+/* Returns the <ack_delay> field value in microsecond to be set in an ACK frame
+ * depending on the time the packet with a new largest packet number was received.
+ */
+static inline uint64_t quic_compute_ack_delay_us(unsigned int time_received,
+                                                 struct quic_conn *conn)
+{
+       return ((now_ms - time_received) * 1000) >> conn->tx.params.ack_delay_exponent;
+}
+
 /* Initialize <dst> transport parameters with default values (when absent)
  * from <quic_dflt_trasports_params>.
  * Never fails.
@@ -981,6 +990,7 @@ static inline void quic_pktns_init(struct quic_pktns *pktns)
        pktns->tx.time_of_last_eliciting = 0;
        pktns->tx.loss_time = TICK_ETERNITY;
        pktns->tx.in_flight = 0;
+       pktns->tx.ack_delay = 0;
 
        pktns->rx.largest_pn = -1;
        pktns->rx.largest_acked_pn = -1;
@@ -988,6 +998,7 @@ static inline void quic_pktns_init(struct quic_pktns *pktns)
        pktns->rx.arngs.sz = 0;
        pktns->rx.arngs.enc_sz = 0;
        pktns->rx.nb_aepkts_since_last_ack = 0;
+       pktns->rx.largest_time_received = 0;
 
        pktns->flags = 0;
 }

diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index ffdbe771a7e65933ec7c99a9a29ffaf9133d77b8..66c3555a4891901d586aa708b0b93cb1e9e72aeb 100644 (file)
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -3621,6 +3621,7 @@ int qc_treat_rx_pkts(struct quic_enc_level *cur_el, struct quic_enc_level *next_
 {
        struct eb64_node *node;
        int64_t largest_pn = -1;
+       unsigned int largest_pn_time_received = 0;
        struct quic_conn *qc = ctx->qc;
        struct quic_enc_level *qel = cur_el;
 
@@ -3657,8 +3658,10 @@ int qc_treat_rx_pkts(struct quic_enc_level *cur_el, struct quic_enc_level *next_
                                        qel->pktns->rx.nb_aepkts_since_last_ack++;
                                        qc_idle_timer_rearm(qc, 1);
                                }
-                               if (pkt->pn > largest_pn)
+                               if (pkt->pn > largest_pn) {
                                        largest_pn = pkt->pn;
+                                       largest_pn_time_received = pkt->time_received;
+                               }
                                /* Update the list of ranges to acknowledge. */
                                if (!quic_update_ack_ranges_list(&qel->pktns->rx.arngs, &ar))
                                        TRACE_DEVEL("Could not update ack range list",
@@ -3671,9 +3674,14 @@ int qc_treat_rx_pkts(struct quic_enc_level *cur_el, struct quic_enc_level *next_
        }
        HA_RWLOCK_WRUNLOCK(QUIC_LOCK, &qel->rx.pkts_rwlock);
 
-       /* Update the largest packet number. */
-       if (largest_pn != -1 && largest_pn > qel->pktns->rx.largest_pn)
+       if (largest_pn != -1 && largest_pn > qel->pktns->rx.largest_pn) {
+               /* Update the largest packet number. */
                qel->pktns->rx.largest_pn = largest_pn;
+               /* Update the largest acknowledged packet timestamps */
+               qel->pktns->rx.largest_time_received = largest_pn_time_received;
+               qel->pktns->flags |= QUIC_FL_PKTNS_NEW_LARGEST_PN;
+       }
+
        if (!qc_treat_rx_crypto_frms(qel, ctx))
                goto err;
 
@@ -5787,9 +5795,15 @@ static int qc_do_build_pkt(unsigned char *pos, const unsigned char *end,
        /* Build an ACK frame if required. */
        ack_frm_len = 0;
        if ((qel->pktns->flags & QUIC_FL_PKTNS_ACK_REQUIRED) && !qel->pktns->tx.pto_probe) {
+           struct quic_arngs *arngs = &qel->pktns->rx.arngs;
            BUG_ON(eb_is_empty(&qel->pktns->rx.arngs.root));
-               ack_frm.tx_ack.ack_delay = 0;
-               ack_frm.tx_ack.arngs = &qel->pktns->rx.arngs;
+               ack_frm.tx_ack.arngs = arngs;
+               if (qel->pktns->flags & QUIC_FL_PKTNS_NEW_LARGEST_PN) {
+                       qel->pktns->tx.ack_delay =
+                               quic_compute_ack_delay_us(qel->pktns->rx.largest_time_received, qc);
+                       qel->pktns->flags &= ~QUIC_FL_PKTNS_NEW_LARGEST_PN;
+               }
+               ack_frm.tx_ack.ack_delay = qel->pktns->tx.ack_delay;
                /* XXX BE CAREFUL XXX : here we reserved at least one byte for the
                 * smallest frame (PING) and <*pn_len> more for the packet number. Note
                 * that from here, we do not know if we will have to send a PING frame.
@@ -6201,6 +6215,7 @@ struct task *quic_lstnr_dghdlr(struct task *t, void *ctx, unsigned int state)
                        if (!pkt)
                                goto err;
 
+                       pkt->time_received = now_ms;
                        quic_rx_packet_refinc(pkt);
                        qc_lstnr_pkt_rcv(pos, end, pkt, first_pkt, dgram);
                        first_pkt = 0;