[PATCH BlueZ v1 08/10] a2dp: Fix refusing the AVDTP connection of a new link

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

When the remote reconnects before the disconnection of the previous
link is processed, the A2DP channel of that link is still registered
and an incoming AVDTP connection on the new link is taken as a
transport channel of its session, and refused.

Process the disconnection of the signalling channel of the existing
session first if it is pending, so the connection is handled as a new
signalling channel.

Assisted-by: Claude:claude-opus-5-5
---
 profiles/audio/a2dp.c  |  7 +++++++
 profiles/audio/avdtp.c | 24 ++++++++++++++++++++++++
 profiles/audio/avdtp.h |  1 +
 3 files changed, 32 insertions(+)

diff --git a/profiles/audio/a2dp.c b/profiles/audio/a2dp.c
index cb1b3a9804e7..3b29ec204d00 100644
--- a/profiles/audio/a2dp.c
+++ b/profiles/audio/a2dp.c
@@ -2796,6 +2796,13 @@ static void confirm_cb(GIOChannel *io, gpointer data)
 		goto drop;
 
 	chan = queue_find(server->channels, match_by_device, device);
+
+	/* The channel of a previous link, if its disconnection was not
+	 * processed yet: this is not a transport channel of it.
+	 */
+	if (chan && chan->session && avdtp_check_disconnected(chan->session))
+		chan = queue_find(server->channels, match_by_device, device);
+
 	if (chan) {
 		struct a2dp_setup *setup;
 
diff --git a/profiles/audio/avdtp.c b/profiles/audio/avdtp.c
index 56d27b973a17..30f80a0c2fd1 100644
--- a/profiles/audio/avdtp.c
+++ b/profiles/audio/avdtp.c
@@ -18,6 +18,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <errno.h>
+#include <poll.h>
 #include <unistd.h>
 #include <assert.h>
 
@@ -1168,6 +1169,29 @@ static void connection_lost(struct avdtp *session, int err)
 	avdtp_unref(session);
 }
 
+/* Process a disconnection of the signalling channel not dispatched yet,
+ * returning whether it is disconnected.
+ */
+bool avdtp_check_disconnected(struct avdtp *session)
+{
+	struct pollfd pfd;
+
+	if (!session->io)
+		return false;
+
+	pfd.fd = g_io_channel_unix_get_fd(session->io);
+	pfd.events = 0;
+	pfd.revents = 0;
+
+	if (poll(&pfd, 1, 0) <= 0 ||
+			!(pfd.revents & (POLLHUP | POLLERR | POLLNVAL)))
+		return false;
+
+	connection_lost(session, ECONNRESET);
+
+	return true;
+}
+
 static bool disconnect_timeout(gpointer user_data)
 {
 	struct avdtp *session = user_data;
diff --git a/profiles/audio/avdtp.h b/profiles/audio/avdtp.h
index 10c8f496b44e..ab5059b055ec 100644
--- a/profiles/audio/avdtp.h
+++ b/profiles/audio/avdtp.h
@@ -205,6 +205,7 @@ typedef void (*avdtp_discover_cb_t) (struct avdtp *session, GSList *seps,
 					struct avdtp_error *err, void *user_data);
 
 void avdtp_unref(struct avdtp *session);
+bool avdtp_check_disconnected(struct avdtp *session);
 struct avdtp *avdtp_ref(struct avdtp *session);
 
 struct avdtp_service_capability *avdtp_service_cap_new(uint8_t category,
-- 
2.56.0