Controller Area Network (CAN) is a slow (up to 1Mbit/s) serial
communications protocol which was developed by Bosch in
1991, mainly for automotive, but now widely used in marine
(NMEA2000), industrial, and medical applications.
More information on the CAN network protocol family PF_CAN
is contained in <Documentation/networking/can.txt>.

If you want CAN support you should say Y here and also to the
specific driver for your controller(s) below.

source code:

net/can/