Indentation should be done with spaces, not with TABs, in the net subsystem
There are still a lot of old files in the QEMU networking code base that use TABs for indentation instead of using spaces in these files here:
hw/net/ne2000.c hw/net/mcf_fec.c hw/net/pcnet.c hw/net/can/ctu_can_fd_frame.h hw/net/can/ctu_can_fd_regs.h hw/net/e1000_regs.h hw/net/pcnet.h net/tap-linux.h
The TABs should be replaced with spaces, to make sure that we have a consistent coding style with an indentation of 4 spaces everywhere.