Bluetooth: Classic: L2CAP: Make TxWindow size on both sides the same

In retransmission mode and flow control mode, the TxWindow size should
be same on both sides.

When one side is updated, also update the other side.

Signed-off-by: Lyle Zhu <[email protected]>

Author: lylezhu2012

subsys/bluetooth/host/classic/l2cap_br.c

@@ -2838,6 +2838,18 @@ static uint16_t l2cap_br_conf_rsp_opt_ret_fc(struct bt_l2cap_chan *chan, struct
 		br_chan->rx.max_transmit = opt_ret_fc->max_transmit;
 		br_chan->rx.max_window = sys_le16_to_cpu(opt_ret_fc->tx_windows_size);
 		br_chan->rx.mps = sys_le16_to_cpu(opt_ret_fc->mps);
+
+		if ((opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_RET) ||
+		    (opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_FC)) {
+			/*
+			 * Bluetooth Core specification Version 6.0 | Vol 3, Part A, section 5.4.
+			 *
+			 * In Retransmission mode and Flow Control mode this parameter should be
+			 * negotiated to reflect the buffer sizes allocated for the connection on
+			 * both sides.
+			 */
+			br_chan->tx.max_window = br_chan->rx.max_window;
+		}
 	}
 
 	if (!accept) {
@@ -3251,6 +3263,18 @@ static uint16_t l2cap_br_conf_rsp_unaccept_opt_ret_fc(struct bt_l2cap_chan *chan
 		br_chan->rx.max_transmit = opt_ret_fc->max_transmit;
 		br_chan->rx.max_window = opt_ret_fc->tx_windows_size;
 		br_chan->rx.mps = sys_le16_to_cpu(opt_ret_fc->mps);
+
+		if ((opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_RET) ||
+		    (opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_FC)) {
+			/*
+			 * Bluetooth Core specification Version 6.0 | Vol 3, Part A, section 5.4.
+			 *
+			 * In Retransmission mode and Flow Control mode this parameter should be
+			 * negotiated to reflect the buffer sizes allocated for the connection on
+			 * both sides.
+			 */
+			br_chan->tx.max_window = br_chan->rx.max_window;
+		}
 	}
 
 	if (br_chan->rx.mode == BT_L2CAP_BR_LINK_MODE_BASIC) {
@@ -3975,6 +3999,18 @@ static uint16_t l2cap_br_conf_opt_ret_fc(struct bt_l2cap_chan *chan, struct net_
 		br_chan->tx.max_transmit = opt_ret_fc->max_transmit;
 		br_chan->tx.max_window = opt_ret_fc->tx_windows_size;
 		br_chan->tx.mps = sys_le16_to_cpu(opt_ret_fc->mps);
+
+		if ((opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_RET) ||
+		    (opt_ret_fc->mode == BT_L2CAP_BR_LINK_MODE_FC)) {
+			/*
+			 * Bluetooth Core specification Version 6.0 | Vol 3, Part A, section 5.4.
+			 *
+			 * In Retransmission mode and Flow Control mode this parameter should be
+			 * negotiated to reflect the buffer sizes allocated for the connection on
+			 * both sides.
+			 */
+			br_chan->rx.max_window = br_chan->tx.max_window;
+		}
 	}
 
 	if (!accept) {