From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 27 Feb 2025 10:33:21 +0000 (+0100)
Subject: MINOR: h3/hq-interop: restore function for standalone FIN receive
X-Git-Tag: v3.2-dev7~13
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=861b11334cd4013e89506601482962a726a07e28;p=thirdparty%2Fhaproxy.git

MINOR: h3/hq-interop: restore function for standalone FIN receive

Previously, a function qcs_http_handle_standalone_fin() was implemented
to handle a received standalone FIN, bypassing app_ops layer decoding.
However, this was removed as app_ops layer interaction is necessary. For
example, HTTP/3 checks that FIN is never sent on the control uni stream.

This patch reintroduces qcs_http_handle_standalone_fin(), albeit in a
slightly diminished version. Most importantly, it is now the
responsibility of the app_ops layer itself to use it, to avoid the
shortcoming described above.

The main objective of this patch is to be able to support standalone FIN
in HTTP/0.9 layer. This is easily done via the reintroduction of
qcs_http_handle_standalone_fin() usage. This will be useful to perform
testing, as standalone FIN is a corner case which can easily be broken.
---

diff --git a/include/haproxy/qmux_http.h b/include/haproxy/qmux_http.h
index 4a7711401..218bd012c 100644
--- a/include/haproxy/qmux_http.h
+++ b/include/haproxy/qmux_http.h
@@ -8,6 +8,9 @@
 
 size_t qcs_http_rcv_buf(struct qcs *qcs, struct buffer *buf, size_t count,
                         char *fin);
+
+int qcs_http_handle_standalone_fin(struct qcs *qcs);
+
 size_t qcs_http_snd_buf(struct qcs *qcs, struct buffer *buf, size_t count,
                         char *fin);
 
diff --git a/src/h3.c b/src/h3.c
index 20023403e..1f16caf13 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1322,21 +1322,8 @@ static ssize_t h3_rcv_buf(struct qcs *qcs, struct buffer *b, int fin)
 	}
 
 	if (!b_data(b) && fin && quic_stream_is_bidi(qcs->id)) {
-		struct buffer *appbuf;
-		struct htx *htx;
-		int eom;
-
 		TRACE_PROTO("received FIN without data", H3_EV_RX_FRAME, qcs->qcc->conn, qcs);
-		if (!(appbuf = qcc_get_stream_rxbuf(qcs))) {
-			TRACE_ERROR("data buffer alloc failure", H3_EV_RX_FRAME, qcs->qcc->conn, qcs);
-			qcc_set_error(qcs->qcc, H3_ERR_INTERNAL_ERROR, 1);
-			goto err;
-		}
-
-		htx = htx_from_buf(appbuf);
-		eom = htx_set_eom(htx);
-		htx_to_buf(htx, appbuf);
-		if (!eom) {
+		if (qcs_http_handle_standalone_fin(qcs)) {
 			TRACE_ERROR("cannot set EOM", H3_EV_RX_FRAME, qcs->qcc->conn, qcs);
 			qcc_set_error(qcs->qcc, H3_ERR_INTERNAL_ERROR, 1);
 			goto err;
diff --git a/src/hq_interop.c b/src/hq_interop.c
index 55cccf134..b31f855c2 100644
--- a/src/hq_interop.c
+++ b/src/hq_interop.c
@@ -23,6 +23,12 @@ static ssize_t hq_interop_rcv_buf(struct qcs *qcs, struct buffer *b, int fin)
 	/* hq-interop parser does not support buffer wrapping. */
 	BUG_ON(b_data(b) != b_contig_data(b, 0));
 
+	if (!b_data(b) && fin && quic_stream_is_bidi(qcs->id)) {
+		if (qcs_http_handle_standalone_fin(qcs))
+			return -1;
+		return 0;
+	}
+
 	/* skip method */
 	while (data && HTTP_IS_TOKEN(*ptr)) {
 		ptr++;
diff --git a/src/qmux_http.c b/src/qmux_http.c
index 092eb15da..b4e85ef22 100644
--- a/src/qmux_http.c
+++ b/src/qmux_http.c
@@ -62,6 +62,27 @@ size_t qcs_http_rcv_buf(struct qcs *qcs, struct buffer *buf, size_t count,
 	return ret;
 }
 
+int qcs_http_handle_standalone_fin(struct qcs *qcs)
+{
+	struct buffer *appbuf;
+	struct htx *htx;
+	int eom;
+
+	if (!(appbuf = qcc_get_stream_rxbuf(qcs)))
+		goto err;
+
+	htx = htx_from_buf(appbuf);
+	eom = htx_set_eom(htx);
+	htx_to_buf(htx, appbuf);
+	if (!eom)
+		goto err;
+
+	return 0;
+
+ err:
+	return -1;
+}
+
 /* QUIC MUX snd_buf operation using HTX data. HTX data will be transferred from
  * <buf> to <qcs> stream buffer. Input buffer is expected to be of length
  * <count>. <fin> will be set to signal the last data to send for this stream.