MINOR: quic: support hq-interop

Implement a new app_ops layer for quic interop. This layer uses HTTP/0.9
on top of QUIC. Implementation is minimal, with the intent to be able to
pass interoperability test suite from
https://github.com/marten-seemann/quic-interop-runner.

It is instantiated if the negotiated ALPN is "hq-interop".

Makefile

@@ -594,7 +594,8 @@ endif
 ifneq ($(USE_QUIC),)
 OPTIONS_OBJS += src/quic_sock.o src/proto_quic.o src/xprt_quic.o src/quic_tls.o \
                 src/quic_frame.o src/quic_cc.o src/quic_cc_newreno.o src/mux_quic.o \
-                src/cbuf.o src/qpack-dec.o src/qpack-tbl.o src/h3.o src/qpack-enc.o
+                src/cbuf.o src/qpack-dec.o src/qpack-tbl.o src/h3.o src/qpack-enc.o \
+                src/hq_interop.o
 endif
 
 ifneq ($(USE_LUA),)

include/haproxy/hq_interop.h

@@ -0,0 +1,6 @@
+#ifndef _HAPROXY_HQ_INTEROP_H_
+#define _HAPROXY_HQ_INTEROP_H_
+
+extern const struct qcc_app_ops hq_interop_ops;
+
+#endif /* _HAPROXY_HQ_INTEROP_H_ */

src/hq_interop.c

@@ -0,0 +1,132 @@
+#include <haproxy/hq_interop.h>
+
+#include <import/ist.h>
+#include <haproxy/buf.h>
+#include <haproxy/connection.h>
+#include <haproxy/dynbuf.h>
+#include <haproxy/htx.h>
+#include <haproxy/http.h>
+#include <haproxy/mux_quic-t.h>
+#include <haproxy/stream.h>
+
+static int hq_interop_decode_qcs(struct qcs *qcs, void *ctx)
+{
+	struct buffer *rxbuf = &qcs->rx.buf;
+	struct htx *htx;
+	struct htx_sl *sl;
+	struct conn_stream *cs;
+	struct buffer htx_buf = BUF_NULL;
+	struct ist path;
+	char *ptr;
+
+	b_alloc(&htx_buf);
+	htx = htx_from_buf(&htx_buf);
+
+	/* skip method */
+	ptr = b_orig(rxbuf);
+	while (HTTP_IS_TOKEN(*ptr))
+		++ptr;
+	BUG_ON(!HTTP_IS_SPHT(*ptr));
+	++ptr;
+
+	/* extract path */
+	BUG_ON(HTTP_IS_LWS(*ptr));
+	path.ptr = ptr;
+	while (!HTTP_IS_LWS(*ptr))
+		++ptr;
+	BUG_ON(!HTTP_IS_LWS(*ptr));
+	path.len = ptr - path.ptr;
+
+	sl = htx_add_stline(htx, HTX_BLK_REQ_SL, 0, ist("GET"), path, ist("HTTP/1.0"));
+	sl->flags |= HTX_SL_F_BODYLESS;
+	sl->info.req.meth = find_http_meth("GET", 3);
+
+	htx_add_endof(htx, HTX_BLK_EOH);
+	htx_to_buf(htx, &htx_buf);
+
+	cs = cs_new(qcs->qcc->conn, qcs->qcc->conn->target);
+	cs->ctx = qcs;
+	stream_create_from_cs(cs, &htx_buf);
+
+	b_del(rxbuf, b_data(rxbuf));
+	b_free(&htx_buf);
+
+	return 0;
+}
+
+static struct buffer *mux_get_buf(struct qcs *qcs)
+{
+	if (!b_size(&qcs->tx.buf))
+		b_alloc(&qcs->tx.buf);
+
+	return &qcs->tx.buf;
+}
+
+static size_t hq_interop_snd_buf(struct conn_stream *cs, struct buffer *buf,
+                                 size_t count, int flags)
+{
+	struct qcs *qcs = cs->ctx;
+	struct htx *htx;
+	enum htx_blk_type btype;
+	struct htx_blk *blk;
+	int32_t idx;
+	uint32_t bsize, fsize;
+	struct buffer *res, outbuf;
+	size_t total = 0;
+
+	htx = htx_from_buf(buf);
+	res = mux_get_buf(qcs);
+	outbuf = b_make(b_tail(res), b_contig_space(res), 0, 0);
+
+	while (count && !htx_is_empty(htx) && !(qcs->flags & QC_SF_BLK_MROOM)) {
+		/* Not implemented : QUIC on backend side */
+		idx = htx_get_head(htx);
+		blk = htx_get_blk(htx, idx);
+		btype = htx_get_blk_type(blk);
+		fsize = bsize = htx_get_blksz(blk);
+
+		BUG_ON(btype == HTX_BLK_REQ_SL);
+
+		switch (btype) {
+		case HTX_BLK_DATA:
+			if (fsize > count)
+				fsize = count;
+			b_putblk(&outbuf, htx_get_blk_ptr(htx, blk), fsize);
+			total += fsize;
+			count -= fsize;
+
+			if (fsize == bsize)
+				htx_remove_blk(htx, blk);
+			else
+				htx_cut_data_blk(htx, blk, fsize);
+			break;
+
+		/* only body is transfered on HTTP/0.9 */
+		case HTX_BLK_RES_SL:
+		case HTX_BLK_TLR:
+		case HTX_BLK_EOT:
+		default:
+			htx_remove_blk(htx, blk);
+			total += bsize;
+			count -= bsize;
+			break;
+		}
+	}
+
+	if ((htx->flags & HTX_FL_EOM) && htx_is_empty(htx))
+		qcs->flags |= QC_SF_FIN_STREAM;
+
+	b_add(res, b_data(&outbuf));
+
+	if (total) {
+		if (!(qcs->qcc->wait_event.events & SUB_RETRY_SEND))
+			tasklet_wakeup(qcs->qcc->wait_event.tasklet);
+	}
+
+	return total;
+}
+
+const struct qcc_app_ops hq_interop_ops = {
+	.decode_qcs = hq_interop_decode_qcs,
+	.snd_buf    = hq_interop_snd_buf,
+};

src/xprt_quic.c

@@ -36,6 +36,7 @@
 #include <haproxy/freq_ctr.h>
 #include <haproxy/global.h>
 #include <haproxy/h3.h>
+#include <haproxy/hq_interop.h>
 #include <haproxy/log.h>
 #include <haproxy/mux_quic.h>
 #include <haproxy/pipe.h>
@@ -1670,6 +1671,9 @@ static inline int qc_provide_cdata(struct quic_enc_level *el,
 		if (!qc->qcc->app_ops->init(qc->qcc))
 			goto err;
 	}
+	else if (alpn_len >= 10 && memcmp(alpn, "hq-interop", 10) == 0) {
+		qc->qcc->app_ops = &hq_interop_ops;
+	}
 	else {
 		/* TODO RFC9001 8.1. Protocol Negotiation
 		 * must return no_application_protocol TLS alert