From 50f193174940187f23e9b68881a796582e0758a0 Mon Sep 17 00:00:00 2001
From: "Alan T. DeKok" <aland@freeradius.org>
Date: Tue, 14 May 2024 19:59:04 -0400
Subject: [PATCH] add framework for RADIUS client bio write blocked / resume
 callbacks

---
 src/lib/bio/packet.h               | 15 +++++--
 src/protocols/radius/client.c      | 66 +++++++++++++++++++++++++++++-
 src/protocols/radius/client.h      |  2 +
 src/protocols/radius/client_priv.h |  1 -
 4 files changed, 77 insertions(+), 7 deletions(-)

diff --git a/src/lib/bio/packet.h b/src/lib/bio/packet.h
index a5a0cb39e5..3809d3aa59 100644
--- a/src/lib/bio/packet.h
+++ b/src/lib/bio/packet.h
@@ -68,17 +68,24 @@ typedef int (*fr_bio_packet_release_t)(fr_bio_packet_t *bio, fr_packet_t *packet
 
 typedef void (*fr_bio_packet_signal_t)(fr_bio_packet_t *bio);
 
+typedef struct {
+	fr_bio_packet_signal_t	read_blocked;
+	fr_bio_packet_signal_t	write_blocked;
+
+	fr_bio_packet_signal_t	read_resume;
+	fr_bio_packet_signal_t	write_resume;
+} fr_bio_packet_cb_funcs_t;
+
 struct fr_bio_packet_s {
 	void			*uctx;		//!< user ctx, caller can manually set it.
 
 	fr_bio_packet_read_t	read;		//!< read from the underlying bio
 	fr_bio_packet_write_t	write;		//!< write to the underlying bio
 
-	fr_bio_packet_signal_t	read_blocked;
-	fr_bio_packet_signal_t	write_blocked;
+	fr_bio_packet_cb_funcs_t cb;
 
-	fr_bio_packet_signal_t	read_resume;
-	fr_bio_packet_signal_t	write_resume;
+	bool			write_blocked;
+	bool			read_blocked;
 
 	fr_bio_t		*bio;		//!< underlying bio for IO
 };
diff --git a/src/protocols/radius/client.c b/src/protocols/radius/client.c
index 5194b90645..adc2b29dd3 100644
--- a/src/protocols/radius/client.c
+++ b/src/protocols/radius/client.c
@@ -146,7 +146,7 @@ int fr_radius_client_fd_bio_write(fr_radius_client_fd_bio_t *my, void *request_c
 		all_ids_used:
 			my->all_ids_used = true;
 
-			if (my->common.write_blocked) my->common.write_blocked(&my->common);
+			if (my->common.cb.write_blocked) my->common.cb.write_blocked(&my->common);
 
 			fr_strerror_const("All IDs are in use");
 			return fr_bio_error(GENERIC);
@@ -313,7 +313,7 @@ static void radius_client_retry_release(fr_bio_t *bio, fr_bio_retry_entry_t *ret
 	if (my->all_ids_used) {
 		my->all_ids_used = false;
 
-		if (!my->write_blocked && my->common.write_resume) my->common.write_resume(&my->common);
+		if (!my->common.write_blocked && my->common.cb.write_resume) my->common.cb.write_resume(&my->common);
 	}
 }
 
@@ -501,3 +501,65 @@ int fr_radius_client_bio_connect(fr_bio_packet_t *bio)
 	my->info.connected = (rcode == 0);
 	return rcode;
 }
+
+/*
+ *	Debounce functions to get to the right callback.
+ */
+static void fr_bio_write_blocked(fr_bio_t *bio)
+{
+	fr_radius_client_fd_bio_t *my = bio->uctx;
+
+	my->common.write_blocked = true;
+
+	my->common.cb.write_blocked(&my->common);
+}
+
+static void fr_bio_write_resume(fr_bio_t *bio)
+{
+	fr_radius_client_fd_bio_t *my = bio->uctx;
+
+	/*
+	 *	IO is unblocked, but we don't have any free IDs.  So we can't yet resume writes.
+	 */
+	if (my->all_ids_used) return;
+
+	my->common.write_blocked = false;
+
+	my->common.cb.write_resume(&my->common);
+}
+
+static void fr_bio_read_blocked(fr_bio_t *bio)
+{
+	fr_radius_client_fd_bio_t *my = bio->uctx;
+
+	my->common.read_blocked = true;
+
+	my->common.cb.read_blocked(&my->common);
+}
+
+static void fr_bio_read_resume(fr_bio_t *bio)
+{
+	fr_radius_client_fd_bio_t *my = bio->uctx;
+
+	my->common.read_blocked = false;
+
+	my->common.cb.read_resume(&my->common);
+}
+
+int fr_radius_client_bio_cb_set(fr_bio_packet_t *bio, fr_bio_packet_cb_funcs_t const *cb)
+{
+	fr_radius_client_fd_bio_t *my = talloc_get_type_abort(bio, fr_radius_client_fd_bio_t);
+	fr_bio_cb_funcs_t bio_cb = {};
+
+#undef SET
+#define SET(_x) if (cb->_x) bio_cb._x = fr_bio_ ## _x
+
+	SET(write_blocked);
+	SET(read_blocked);
+	SET(write_resume);
+	SET(read_resume);
+
+	(void) fr_bio_cb_set(my->fd, &bio_cb);
+
+	return 0;
+}
diff --git a/src/protocols/radius/client.h b/src/protocols/radius/client.h
index 6d7579705d..cafde75784 100644
--- a/src/protocols/radius/client.h
+++ b/src/protocols/radius/client.h
@@ -62,3 +62,5 @@ fr_radius_client_bio_info_t const *fr_radius_client_bio_info(fr_bio_packet_t *bi
 size_t		fr_radius_client_bio_outstanding(fr_bio_packet_t *bio) CC_HINT(nonnull);
 
 int		fr_radius_client_bio_force_id(fr_bio_packet_t *bio, int code, int id);
+
+int		fr_radius_client_bio_cb_set(fr_bio_packet_t *bio, fr_bio_packet_cb_funcs_t const *cb);
diff --git a/src/protocols/radius/client_priv.h b/src/protocols/radius/client_priv.h
index a0ae5d2a7c..c2e6580f95 100644
--- a/src/protocols/radius/client_priv.h
+++ b/src/protocols/radius/client_priv.h
@@ -46,7 +46,6 @@ typedef struct {
 	fr_bio_t		*fd;
 
 	bool			all_ids_used;		//!< ALL IDs are used.
-	bool			write_blocked;
 
 	fr_radius_client_bio_info_t info;
 
-- 
2.47.3