How to get mobile number in session?

How to get mobile number in session?

public function register(Request $request, User $user)
{
    $code = rand(10000,99999);
    session(['mobile' => $request->mobile ]);
    $mobile = session('mobile');
    $user = \App\User::create([
        'first_name' => $request->first_name,
        'last_name' => $request->last_name,
        'gender' => $request->gender,
        'mobile' => $request->mobile,
        'code' => $code,
        'address' => $request->address,
        'birth_date' => $request->birth_date,
        'province_id' => $request->province_id,
        'city_id' => $request->city_id,
        'email' => $request->email,
        'password' => bcrypt($request->password)
    ]);

    if($request->hasFile('image')) {
        $image = $request->file('image');
        $filename = $image->getClientOriginalName();
        $image->move(public_path('images/users'), $filename);
        $user->image = $request->file('image')->getClientOriginalName();
    }

    if ($user->save()) {
        try {
            $api = new \Kavenegar\KavenegarApi("Api Key");
            $sender = "10004346";
            $message  = $code;
            $receptor = $user->mobile;
            $result = $api->Send($sender, $receptor, $message);
            if ($result) {
                foreach ($result as $r) {
                    echo "messageid = $r->messageid";
                    echo "message = $r->message";
                    echo "status = $r->status";
                    echo "statustext = $r->statustext";
                    echo "sender = $r->sender";
                    echo "receptor = $r->receptor";
                    echo "date = $r->date";
                    echo "cost = $r->cost";
                }
            }
        } catch (\Kavenegar\Exceptions\ApiException $e) {
            echo $e->errorMessage();
        } catch (\Kavenegar\Exceptions\HttpException $e) {
            echo $e->errorMessage();
        }
    }
    return redirect()->route('code/?mobile'.$mobile);
}

But i get this error:

Route [code/?mobile09123456789] not defined.