From 54445d04e4adb3e254033141020be7e55f2465e9 Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 10 Mar 2022 16:44:14 +0100
Subject: [PATCH] MINOR: quic: implement sending confirmation

Implement a new MUX function qcc_notify_send. This function must be
called by the transport layer to confirm the sending of STREAM data to
the MUX.

For the moment, the function has no real purpose. However, it will be
useful to solve limitations on push frame and implement the flow
control.
---
 include/haproxy/mux_quic.h |  1 +
 src/mux_quic.c             | 13 +++++++++++++
 src/xprt_quic.c            | 17 +++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/include/haproxy/mux_quic.h b/include/haproxy/mux_quic.h
index 56bbad5db..a5b105376 100644
--- a/include/haproxy/mux_quic.h
+++ b/include/haproxy/mux_quic.h
@@ -23,6 +23,7 @@ void qcs_notify_send(struct qcs *qcs);
 int qcc_recv(struct qcc *qcc, uint64_t id, uint64_t len, uint64_t offset,
              char fin, char *data, struct qcs **out_qcs);
 int qcc_decode_qcs(struct qcc *qcc, struct qcs *qcs);
+void qcc_streams_sent_done(struct qcs *qcs, uint64_t data, uint64_t offset);
 
 /* Bit shift to get the stream sub ID for internal use which is obtained
  * shifting the stream IDs by this value, knowing that the
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 0f6f6b82b..e12edcc95 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -400,6 +400,19 @@ static int qcs_push_frame(struct qcs *qcs, struct buffer *payload, int fin, uint
 	return -1;
 }
 
+/* This function must be called by the upper layer to inform about the sending
+ * of a STREAM frame for <qcs> instance. The frame is of <data> length and on
+ * <offset>.
+ */
+void qcc_streams_sent_done(struct qcs *qcs, uint64_t data, uint64_t offset)
+{
+	/* check if the STREAM frame has already been notified. It can happen
+	 * for retransmission.
+	 */
+	if (offset + data <= qcs->tx.sent_offset)
+		return;
+}
+
 /* Wrapper for send on transport layer. Send a list of frames <frms> for the
  * connection <qcc>.
  *
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 7f3b02aeb..bfe888f3b 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -4889,6 +4889,10 @@ static inline int qc_build_frms(struct list *outlist, struct list *inlist,
 				/* <cf> STREAM data have been consumed. */
 				LIST_DELETE(&cf->list);
 				LIST_APPEND(outlist, &cf->list);
+
+				qcc_streams_sent_done(cf->stream.qcs,
+				                      cf->stream.len,
+				                      cf->stream.offset.key);
 			}
 			else {
 				struct quic_frame *new_cf;
@@ -4920,7 +4924,20 @@ static inline int qc_build_frms(struct list *outlist, struct list *inlist,
 				cf->stream.len -= dlen;
 				cf->stream.offset.key += dlen;
 				cf->stream.data = (unsigned char *)b_peek(&cf_buf, dlen);
+
+				qcc_streams_sent_done(new_cf->stream.qcs,
+				                      new_cf->stream.len,
+				                      new_cf->stream.offset.key);
 			}
+
+			/* TODO the MUX is notified about the frame sending via
+			 * previous qcc_streams_sent_done call. However, the
+			 * sending can fail later, for example if the sendto
+			 * system call returns an error. As the MUX has been
+			 * notified, the transport layer is responsible to
+			 * bufferize and resent the announced data later.
+			 */
+
 			break;
 
 		default: