MEDIUM: quic: Limit the number of ACK ranges
When building a packet with an ACK frame, we store the largest acknowledged
packet number sent in this frame in the packet (quic_tx_packet struc).
When receiving an ack for such a packet we can purge the tree of acknowledged
packet number ranges from the range sent before this largest acknowledged
packet number.
diff --git a/include/haproxy/xprt_quic.h b/include/haproxy/xprt_quic.h
index d95a072..9035fd9 100644
--- a/include/haproxy/xprt_quic.h
+++ b/include/haproxy/xprt_quic.h
@@ -991,6 +991,17 @@
pktns->flags = 0;
}
+/* Returns the current largest acknowledged packet number if exists, -1 if not */
+static inline int64_t quic_pktns_get_largest_acked_pn(struct quic_pktns *pktns)
+{
+ struct eb64_node *ar = eb64_last(&pktns->rx.arngs.root);
+
+ if (!ar)
+ return -1;
+
+ return eb64_entry(&ar->node, struct quic_arng_node, first)->last;
+}
+
/* Discard <pktns> packet number space attached to <qc> QUIC connection.
* Its loss information are reset. Deduce the outstanding bytes for this
* packet number space from the outstanding bytes for the path of this
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index ddd0b01..1b164c7 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -1559,6 +1559,40 @@
}
}
+/* Remove already sent ranges of acknowledged packet numbers from
+ * <pktns> packet number space tree below <largest_acked_pn> possibly
+ * updating the range which contains <largest_acked_pn>.
+ * Never fails.
+ */
+static void qc_treat_ack_of_ack(struct quic_pktns *pktns,
+ int64_t largest_acked_pn)
+{
+ struct eb64_node *ar, *next_ar;
+ struct quic_arngs *arngs = &pktns->rx.arngs;
+
+ ar = eb64_first(&arngs->root);
+ while (ar) {
+ struct quic_arng_node *ar_node;
+
+ next_ar = eb64_next(ar);
+ ar_node = eb64_entry(&ar->node, struct quic_arng_node, first);
+ if ((int64_t)ar_node->first.key > largest_acked_pn)
+ break;
+
+ if (largest_acked_pn < ar_node->last) {
+ eb64_delete(ar);
+ ar_node->first.key = largest_acked_pn + 1;
+ eb64_insert(&arngs->root, ar);
+ break;
+ }
+
+ eb64_delete(ar);
+ pool_free(pool_head_quic_arng, ar_node);
+ arngs->sz--;
+ ar = next_ar;
+ }
+}
+
/* Send a packet ack event nofication for each newly acked packet of
* <newly_acked_pkts> list and free them.
* Always succeeds.
@@ -1575,6 +1609,12 @@
qc->path->in_flight -= pkt->in_flight_len;
if (pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING)
qc->path->ifae_pkts--;
+ /* If this packet contained an ACK frame, proceed to the
+ * acknowledging of range of acks from the largest acknowledged
+ * packet number which was sent in an ACK frame by this packet.
+ */
+ if (pkt->largest_acked_pn != -1)
+ qc_treat_ack_of_ack(pkt->pktns, pkt->largest_acked_pn);
ev.ack.acked = pkt->in_flight_len;
ev.ack.time_sent = pkt->time_sent;
quic_cc_event(&qc->path->cc, &ev);
@@ -5006,7 +5046,7 @@
struct quic_frame ack_frm = { .type = QUIC_FT_ACK, };
struct quic_frame cc_frm = { . type = QUIC_FT_CONNECTION_CLOSE, };
size_t ack_frm_len, head_len;
- int64_t largest_acked_pn;
+ int64_t rx_largest_acked_pn;
int add_ping_frm;
struct list frm_list = LIST_HEAD_INIT(frm_list);
@@ -5036,9 +5076,9 @@
goto no_room;
end -= QUIC_TLS_TAG_LEN;
- largest_acked_pn = HA_ATOMIC_LOAD(&qel->pktns->rx.largest_acked_pn);
+ rx_largest_acked_pn = HA_ATOMIC_LOAD(&qel->pktns->rx.largest_acked_pn);
/* packet number length */
- *pn_len = quic_packet_number_length(pn, largest_acked_pn);
+ *pn_len = quic_packet_number_length(pn, rx_largest_acked_pn);
/* Build the header */
if ((pkt->type == QUIC_PACKET_TYPE_SHORT &&
!quic_build_packet_short_header(&pos, end, *pn_len, qc, qel->tls_ctx.flags)) ||
@@ -5137,8 +5177,12 @@
if (!quic_packet_number_encode(&pos, end, pn, *pn_len))
goto no_room;
- if (ack_frm_len && !qc_build_frm(&pos, end, &ack_frm, pkt, qc))
- goto no_room;
+ if (ack_frm_len) {
+ if (!qc_build_frm(&pos, end, &ack_frm, pkt, qc))
+ goto no_room;
+
+ pkt->largest_acked_pn = quic_pktns_get_largest_acked_pn(qel->pktns);
+ }
/* Ack-eliciting frames */
if (!LIST_ISEMPTY(&frm_list)) {
@@ -5201,6 +5245,7 @@
pkt->pn_node.key = (uint64_t)-1;
LIST_INIT(&pkt->frms);
pkt->next = NULL;
+ pkt->largest_acked_pn = -1;
pkt->refcnt = 1;
}