Linksys WRT3200ACM, no port mirroring?

I need to check the traffic between my iPhone and satellite receiver and had planned to hook up my MacBook to one of the lan ports and use port mirroring, but I can’t find any setting for this in the switch/VLAN menu. Is this just an omission in LEDE or is it a hw limitation of this otherwise excellent router?

I have a TP-Link Archer C7 and a Netgear WNDR4300 that both have this capability, all running the same version LEDE.

how about, you use tcpdump on the router?

Yeah, that might work, but I can also use my old Netgear router temporarily and use Wireshark on the Mac. I was just surprised that it was not available on the Linksys and would like to know the reason. Apparently the switch is different, no idea if the Marvell switch in the Linksys lacks this functionality.