SocketCAN is a set of open source CAN drivers and a networking stack, and is included in many Linux distributions.
Many Kvaser CAN interfaces are supported by SocketCAN, including Leaf, USBcan and PCI cards.  Supported hardware information can be found at http://elinux.org/CAN_Bus#SocketCAN_Supported_Controllers
Please note that SocketCAN is not maintained or developed by Kvaser, so we have very little influence over which interfaces will be supported.