From 663416b4ef2fafcffa61c04aa09056853d9674f7 Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 1 Aug 2024 11:35:04 +0200
Subject: [PATCH] MINOR: quic: dump quic_conn debug string for logs

Define a new xprt_ops callback named dump_info. This can be used to
extend MUX debug string with infos from the lower layer.

Implement dump_info for QUIC stack. For now, only minimal info are
reported : bytes in flight and size of the sending window. This should
allow to detect if the congestion controller is fine. These info are
reported via QUIC MUX debug string sample.
---
 include/haproxy/connection-t.h | 1 +
 include/haproxy/quic_trace.h   | 6 ++++++
 src/mux_quic.c                 | 3 +++
 src/quic_trace.c               | 8 ++++++++
 src/xprt_quic.c                | 7 +++++++
 5 files changed, 25 insertions(+)

diff --git a/include/haproxy/connection-t.h b/include/haproxy/connection-t.h
index 7119c0c20d..228f2078c4 100644
--- a/include/haproxy/connection-t.h
+++ b/include/haproxy/connection-t.h
@@ -404,6 +404,7 @@ struct xprt_ops {
 	int (*add_xprt)(struct connection *conn, void *xprt_ctx, void *toadd_ctx, const struct xprt_ops *toadd_ops, void **oldxprt_ctx, const struct xprt_ops **oldxprt_ops); /* Add a new XPRT as the new xprt, and return the old one */
 	struct ssl_sock_ctx *(*get_ssl_sock_ctx)(struct connection *); /* retrieve the ssl_sock_ctx in use, or NULL if none */
 	int (*show_fd)(struct buffer *, const struct connection *, const void *ctx); /* append some data about xprt for "show fd"; returns non-zero if suspicious */
+	void (*dump_info)(struct buffer *, const struct connection *);
 };
 
 /* mux_ops describes the mux operations, which are to be performed at the
diff --git a/include/haproxy/quic_trace.h b/include/haproxy/quic_trace.h
index 19fe864307..ddfd3cc958 100644
--- a/include/haproxy/quic_trace.h
+++ b/include/haproxy/quic_trace.h
@@ -23,6 +23,10 @@
 
 #include <haproxy/quic_trace-t.h>
 
+#include <haproxy/buf-t.h>
+
+struct quic_conn;
+
 #define TRACE_SOURCE    &trace_quic
 
 /* Initializes a enc_debug_info struct (only for debug purpose) */
@@ -37,4 +41,6 @@ static inline void enc_debug_info_init(struct enc_debug_info *edi,
 	edi->pn = pn;
 }
 
+void quic_dump_qc_info(struct buffer *msg, const struct quic_conn *qc);
+
 #endif /* _HAPROXY_QUIC_TRACE_H */
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 4ea46bd15c..ddaea06228 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -3226,6 +3226,9 @@ static int qmux_sctl(struct stconn *sc, enum mux_sctl_type mux_sctl, void *outpu
 		if (dbg_ctx->arg.debug_flags & MUX_SCTL_DBG_STR_L_CONN)
 			chunk_appendf(buf, " conn.flg=%#08x", qcc->conn->flags);
 
+		if (dbg_ctx->arg.debug_flags & MUX_SCTL_DBG_STR_L_XPRT)
+			qcc->conn->xprt->dump_info(buf, qcc->conn);
+
 		dbg_ctx->ret.buf = *buf;
 		return ret;
 
diff --git a/src/quic_trace.c b/src/quic_trace.c
index bd7a886107..ce683f6571 100644
--- a/src/quic_trace.c
+++ b/src/quic_trace.c
@@ -12,6 +12,8 @@
 
 #include <inttypes.h>
 
+#include <haproxy/api-t.h>
+#include <haproxy/chunk.h>
 #include <haproxy/quic_conn.h>
 #include <haproxy/quic_tls.h>
 #include <haproxy/quic_trace.h>
@@ -631,3 +633,9 @@ static void quic_trace(enum trace_level level, uint64_t mask, const struct trace
 	}
 
 }
+
+void quic_dump_qc_info(struct buffer *msg, const struct quic_conn *qc)
+{
+	chunk_appendf(msg, " qc.wnd=%llu/%llu", (ullong)qc->path->in_flight,
+	                                        (ullong)qc->path->cwnd);
+}
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 558d1a5975..d6d1a16708 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -11,6 +11,7 @@
  */
 
 #include <haproxy/api.h>
+#include <haproxy/buf.h>
 #include <haproxy/connection.h>
 #include <haproxy/quic_conn.h>
 #include <haproxy/ssl_sock.h>
@@ -161,6 +162,11 @@ static struct ssl_sock_ctx *qc_get_ssl_sock_ctx(struct connection *conn)
 	return conn->handle.qc->xprt_ctx;
 }
 
+static void qc_xprt_dump_info(struct buffer *msg, const struct connection *conn)
+{
+	quic_dump_qc_info(msg, conn->handle.qc);
+}
+
 /* transport-layer operations for QUIC connections. */
 static struct xprt_ops ssl_quic = {
 	.close    = quic_close,
@@ -172,6 +178,7 @@ static struct xprt_ops ssl_quic = {
 	.destroy_bind_conf = ssl_sock_destroy_bind_conf,
 	.get_alpn = ssl_sock_get_alpn,
 	.get_ssl_sock_ctx = qc_get_ssl_sock_ctx,
+	.dump_info = qc_xprt_dump_info,
 	.name     = "QUIC",
 };