You can set the filters to only allow certain messages to be received. Or you can let them all in.
I've not done CAN for vehicles, but devloped my own network. CAN messages can have an 11 bit or 29 bit identifier. I've only done 11 bit.
The filter hardware is such that you can have either
2 x 32 bit filters
4 x 16 bit filters
8 x 8 bit filters
I've done 8 x 8 filters. The 8 bit filters only look at the first 8 bits of the identifier.
Each filter has 2 registers you have to program, a mask register (MR or CANIDMR) and an acceptance register (AR or CANIDAR).
Mask Register = set bit to 1 if you don't care
Acceptance Register = match to bit you
So if you want to receive a message 10101010 (first 8 bits of ID)
You can set the Mask = 00000000
And the AR = 10101010
If you want to receive a group of messages 1010XXXX (x = dont care)
MR = 00001111
AR = 10100000