How could i know which lan port data's come from?

Firstly, I have to say i am totally newbie LOL.
And i made a bridge for all lan ports. How could i know data lan ports datas come from? Thank u guys

What router are you using?

actually, i am not quite sure. could you give me some commands that i go figure out.
ps: it's POL wireless project for a campus. there are a amount of APs in one building, every ap might includes cameras'vlan, teacher's vlan, student's vlan in lan ports.
i tried to ssh in that ap, i found that is totally based on openwrt, but i really don't know much about that, i inputed "ifconfig" to see how many interfaces there are, but i didn't see any about lan but wan and wifi, i think i better make some screenshots for you, I'll do it ASAP.