Bluetooth: Request L2CAP fixed channel list if available

If the extended features mask indicates support for fixed channels,
request the list of available fixed channels. This also enables the
fixed channel features bit so remote implementations can request
information about it. Currently only the signal channel will be
listed.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/l2cap.h

@@ -185,6 +185,7 @@ struct l2cap_info_rsp {
 /* info type */
 #define L2CAP_IT_CL_MTU     0x0001
 #define L2CAP_IT_FEAT_MASK  0x0002
+#define L2CAP_IT_FIXED_CHAN 0x0003
 
 /* info result */
 #define L2CAP_IR_SUCCESS    0x0000

net/bluetooth/l2cap.c

@@ -50,9 +50,10 @@
 #include <net/bluetooth/hci_core.h>
 #include <net/bluetooth/l2cap.h>
 
-#define VERSION "2.12"
+#define VERSION "2.13"
 
-static u32 l2cap_feat_mask = 0x0000;
+static u32 l2cap_feat_mask = 0x0080;
+static u8 l2cap_fixed_chan[8] = { 0x02, };
 
 static const struct proto_ops l2cap_sock_ops;
 
@@ -456,9 +457,8 @@ static void l2cap_info_timeout(unsigned long arg)
 {
 	struct l2cap_conn *conn = (void *) arg;
 
-	conn->info_ident = 0;
-
 	conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
+	conn->info_ident = 0;
 
 	l2cap_conn_start(conn);
 }
@@ -1793,10 +1793,10 @@ static inline int l2cap_command_rej(struct l2cap_conn *conn, struct l2cap_cmd_hd
 
 	if ((conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) &&
 					cmd->ident == conn->info_ident) {
-		conn->info_ident = 0;
 		del_timer(&conn->info_timer);
 
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
+		conn->info_ident = 0;
 
 		l2cap_conn_start(conn);
 	}
@@ -2165,6 +2165,14 @@ static inline int l2cap_information_req(struct l2cap_conn *conn, struct l2cap_cm
 		put_unaligned(cpu_to_le32(l2cap_feat_mask), (__le32 *) rsp->data);
 		l2cap_send_cmd(conn, cmd->ident,
 					L2CAP_INFO_RSP, sizeof(buf), buf);
+	} else if (type == L2CAP_IT_FIXED_CHAN) {
+		u8 buf[12];
+		struct l2cap_info_rsp *rsp = (struct l2cap_info_rsp *) buf;
+		rsp->type   = cpu_to_le16(L2CAP_IT_FIXED_CHAN);
+		rsp->result = cpu_to_le16(L2CAP_IR_SUCCESS);
+		memcpy(buf + 4, l2cap_fixed_chan, 8);
+		l2cap_send_cmd(conn, cmd->ident,
+					L2CAP_INFO_RSP, sizeof(buf), buf);
 	} else {
 		struct l2cap_info_rsp rsp;
 		rsp.type   = cpu_to_le16(type);
@@ -2186,14 +2194,28 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn, struct l2cap_cm
 
 	BT_DBG("type 0x%4.4x result 0x%2.2x", type, result);
 
-	conn->info_ident = 0;
-
 	del_timer(&conn->info_timer);
 
 	if (type == L2CAP_IT_FEAT_MASK) {
 		conn->feat_mask = get_unaligned_le32(rsp->data);
 
+		if (conn->feat_mask & 0x0080) {
+			struct l2cap_info_req req;
+			req.type = cpu_to_le16(L2CAP_IT_FIXED_CHAN);
+
+			conn->info_ident = l2cap_get_ident(conn);
+
+			l2cap_send_cmd(conn, conn->info_ident,
+					L2CAP_INFO_REQ, sizeof(req), &req);
+		} else {
+			conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
+			conn->info_ident = 0;
+
+			l2cap_conn_start(conn);
+		}
+	} else if (type == L2CAP_IT_FIXED_CHAN) {
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
+		conn->info_ident = 0;
 
 		l2cap_conn_start(conn);
 	}