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From: Iulia Tanasescu <iulia.tanasescu@nxp.com>
To: linux-bluetooth@vger.kernel.org
Cc: claudia.rosu@nxp.com,
	mihai-octavian.urzica@nxp.com,
	silviu.barbulescu@nxp.com,
	vlad.pruteanu@nxp.com,
	andrei.istodorescu@nxp.com,
	luiz.dentz@gmail.com,
	Iulia Tanasescu <iulia.tanasescu@nxp.com>
Subject: [PATCH 1/1] Bluetooth: ISO: Avoid creating child socket if PA sync is terminating
Date: Wed, 29 Nov 2023 18:28:42 +0200
Message-Id: <20231129162842.3596-2-iulia.tanasescu@nxp.com>
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When a PA sync socket is closed, the associated hcon is also unlinked
and cleaned up. If there are no other hcons marked with the
HCI_CONN_PA_SYNC flag, HCI_OP_LE_PA_TERM_SYNC is sent to controller.

Between the time of the command and the moment PA sync is terminated
in controller, residual BIGInfo reports might continue to come.
This causes a new PA sync hcon to be added, and a new socket to be
notified to user space.

This commit fixs this by adding a flag on a Broadcast listening
socket to mark when the PA sync child has been closed.

This flag is checked when BIGInfo reports are indicated in
iso_connect_ind, to avoid recreating a hcon and socket if
residual reports arrive before PA sync is terminated.

Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
---
 net/bluetooth/iso.c | 51 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index e49f00e8a6a6..04f6572d35f1 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -54,6 +54,7 @@ static void iso_sock_kill(struct sock *sk);
 enum {
 	BT_SK_BIG_SYNC,
 	BT_SK_PA_SYNC,
+	BT_SK_PA_SYNC_TERM,
 };
 
 struct iso_pinfo {
@@ -82,6 +83,11 @@ static bool iso_match_sid(struct sock *sk, void *data);
 static bool iso_match_sync_handle(struct sock *sk, void *data);
 static void iso_sock_disconn(struct sock *sk);
 
+typedef bool (*iso_sock_match_t)(struct sock *sk, void *data);
+
+static struct sock *iso_get_sock_listen(bdaddr_t *src, bdaddr_t *dst,
+					iso_sock_match_t match, void *data);
+
 /* ---- ISO timers ---- */
 #define ISO_CONN_TIMEOUT	(HZ * 40)
 #define ISO_DISCONN_TIMEOUT	(HZ * 2)
@@ -190,10 +196,21 @@ static void iso_chan_del(struct sock *sk, int err)
 	sock_set_flag(sk, SOCK_ZAPPED);
 }
 
+static bool iso_match_conn_sync_handle(struct sock *sk, void *data)
+{
+	struct hci_conn *hcon = data;
+
+	if (test_bit(BT_SK_PA_SYNC, &iso_pi(sk)->flags))
+		return false;
+
+	return hcon->sync_handle == iso_pi(sk)->sync_handle;
+}
+
 static void iso_conn_del(struct hci_conn *hcon, int err)
 {
 	struct iso_conn *conn = hcon->iso_data;
 	struct sock *sk;
+	struct sock *parent;
 
 	if (!conn)
 		return;
@@ -209,6 +226,25 @@ static void iso_conn_del(struct hci_conn *hcon, int err)
 
 	if (sk) {
 		lock_sock(sk);
+
+		/* While a PA sync hcon is in the process of closing,
+		 * mark parent socket with a flag, so that any residual
+		 * BIGInfo adv reports that arrive before PA sync is
+		 * terminated are not processed anymore.
+		 */
+		if (test_bit(BT_SK_PA_SYNC, &iso_pi(sk)->flags)) {
+			parent = iso_get_sock_listen(&hcon->src,
+						     &hcon->dst,
+						     iso_match_conn_sync_handle,
+						     hcon);
+
+			if (parent) {
+				set_bit(BT_SK_PA_SYNC_TERM,
+					&iso_pi(parent)->flags);
+				sock_put(parent);
+			}
+		}
+
 		iso_sock_clear_timer(sk);
 		iso_chan_del(sk, err);
 		release_sock(sk);
@@ -545,8 +581,6 @@ static struct sock *__iso_get_sock_listen_by_sid(bdaddr_t *ba, bdaddr_t *bc,
 	return NULL;
 }
 
-typedef bool (*iso_sock_match_t)(struct sock *sk, void *data);
-
 /* Find socket listening:
  * source bdaddr (Unicast)
  * destination bdaddr (Broadcast only)
@@ -1888,9 +1922,20 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 		/* Try to get PA sync listening socket, if it exists */
 		sk = iso_get_sock_listen(&hdev->bdaddr, bdaddr,
 						iso_match_pa_sync_flag, NULL);
-		if (!sk)
+
+		if (!sk) {
 			sk = iso_get_sock_listen(&hdev->bdaddr, bdaddr,
 						 iso_match_sync_handle, ev2);
+
+			/* If PA Sync is in process of terminating,
+			 * do not handle any more BIGInfo adv reports.
+			 */
+
+			if (sk && test_bit(BT_SK_PA_SYNC_TERM,
+					   &iso_pi(sk)->flags))
+				return lm;
+		}
+
 		if (sk) {
 			int err;
 
-- 
2.39.2