Bluetooth: bnep: Handle BNEP connection setup request

With this patch kernel will be able to handle setup request. This is
needed if we would like to handle control mesages with extension
headers. User space will be only resposible for reading setup data and
checking if scenario is conformance to specification (dst and src device
bnep role). In case of new user space, setup data must be leaved(peek
msg) on queue. New bnep session will be responsible for handling this
data.

Signed-off-by: Grzegorz Kolodziejczyk <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

net/bluetooth/bnep/bnep.h

···
 #define BNEPGETCONNINFO	_IOR('B', 211, int)
 #define BNEPGETSUPPFEAT	_IOR('B', 212, int)
 
+#define BNEP_SETUP_RESPONSE	0
+#define BNEP_SETUP_RSP_SENT	10
+
 struct bnep_connadd_req {
 	int   sock;		/* Connected socket */
 	__u32 flags;

net/bluetooth/bnep/core.c

···
 		break;
 
 	case BNEP_SETUP_CONN_REQ:
-		err = bnep_send_rsp(s, BNEP_SETUP_CONN_RSP, BNEP_CONN_NOT_ALLOWED);
+		/* Successful response should be sent only once */
+		if (test_bit(BNEP_SETUP_RESPONSE, &s->flags) &&
+		    !test_and_set_bit(BNEP_SETUP_RSP_SENT, &s->flags))
+			err = bnep_send_rsp(s, BNEP_SETUP_CONN_RSP,
+					    BNEP_SUCCESS);
+		else
+			err = bnep_send_rsp(s, BNEP_SETUP_CONN_RSP,
+					    BNEP_CONN_NOT_ALLOWED);
 		break;
 
 	default: {
···
 
 int bnep_add_connection(struct bnep_connadd_req *req, struct socket *sock)
 {
-	u32 valid_flags = 0;
+	u32 valid_flags = BIT(BNEP_SETUP_RESPONSE);
 	struct net_device *dev;
 	struct bnep_session *s, *ss;
 	u8 dst[ETH_ALEN], src[ETH_ALEN];
···
 	s->sock  = sock;
 	s->role  = req->role;
 	s->state = BT_CONNECTED;
+	s->flags = req->flags;
 
 	s->msg.msg_flags = MSG_NOSIGNAL;
 
···
 
 static void __bnep_copy_ci(struct bnep_conninfo *ci, struct bnep_session *s)
 {
-	u32 valid_flags = 0;
+	u32 valid_flags = BIT(BNEP_SETUP_RESPONSE);
 
 	memset(ci, 0, sizeof(*ci));
 	memcpy(ci->dst, s->eh.h_source, ETH_ALEN);

net/bluetooth/bnep/sock.c

···
 	struct bnep_conninfo ci;
 	struct socket *nsock;
 	void __user *argp = (void __user *)arg;
-	__u32 supp_feat = 0;
+	__u32 supp_feat = BIT(BNEP_SETUP_RESPONSE);
 	int err;
 
 	BT_DBG("cmd %x arg %lx", cmd, arg);