From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Mon, 22 Jun 2026 12:36:16 +0000 (+0200)
Subject: BUG/MINOR: hq-interop: support response buffer wrapping
X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;p=thirdparty%2Fhaproxy.git

BUG/MINOR: hq-interop: support response buffer wrapping

When using QUIC on the backend side, transcoding of a large HTTP
response may cause the rxbuf to wrap. This patch introduces buffer
wrapping support for the HTTP/0.9 transcoder. This is similar to what is
already implemented in HTTP/3 layer.

This should be backported up to 3.3.
---

diff --git a/src/hq_interop.c b/src/hq_interop.c
index f1b366e50..3868cb2c4 100644
--- a/src/hq_interop.c
+++ b/src/hq_interop.c
@@ -116,9 +116,10 @@ static ssize_t hq_interop_rcv_buf_res(struct qcs *qcs, struct buffer *b, int fin
 	struct htx_sl *sl;
 	struct buffer *htx_buf;
 	const unsigned int flags = HTX_SL_F_VER_11|HTX_SL_F_XFER_LEN;
-	size_t to_copy = b_data(b);
+	size_t to_copy = b_contig_data(b, 0);
 	size_t htx_sent = 0;
 	uint32_t htx_space;
+	char *head;
 
 	htx_buf = qcc_get_stream_rxbuf(qcs);
 	BUG_ON(!htx_buf);
@@ -144,8 +145,8 @@ static ssize_t hq_interop_rcv_buf_res(struct qcs *qcs, struct buffer *b, int fin
 		}
 	}
 	else {
-		BUG_ON(b_head(b) + to_copy > b_wrap(b)); /* TODO */
-
+		head = b_head(b);
+ retry:
 		htx_space = htx_free_data_space(htx);
 		if (!htx_space) {
 			qcs->flags |= QC_SF_DEM_FULL;
@@ -157,6 +158,19 @@ static ssize_t hq_interop_rcv_buf_res(struct qcs *qcs, struct buffer *b, int fin
 			fin = 0;
 		}
 
+		if (b_head(b) + to_copy > b_wrap(b)) {
+			size_t contig = b_wrap(b) - head;
+			htx_sent = htx_add_data(htx, ist2(b_head(b), contig));
+			if (htx_sent < contig) {
+				qcs->flags |= QC_SF_DEM_FULL;
+				goto out;
+			}
+
+			to_copy -= contig;
+			head = b_orig(b);
+			goto retry;
+		}
+
 		htx_sent = htx_add_data(htx, ist2(b_head(b), to_copy));
 		if (htx_sent < to_copy) {
 			qcs->flags |= QC_SF_DEM_FULL;
@@ -175,9 +189,6 @@ static ssize_t hq_interop_rcv_buf_res(struct qcs *qcs, struct buffer *b, int fin
 /* Returns the amount of decoded bytes from <b> or a negative error code. */
 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));
-
 	return !(qcs->qcc->flags & QC_CF_IS_BACK) ?
 	  hq_interop_rcv_buf_req(qcs, b, fin) :
 	  hq_interop_rcv_buf_res(qcs, b, fin);