Any ISP-provided gateway will be closed source. Cisco products are closed source. Netgear products are closed source. TP-Link products are closed source.

Any ISP-provided gateway will be closed source. Cisco products are closed source. Netgear products are closed source. TP-Link products are closed source. Aruba products are closed source. To my knowledge, the only viable open-source project is that one Linksys router/AP combo, and that doesn't necessarily fit the features someone might be looking for. While it's nice to think everything could be open source, in the hardware/firmware world it's just not common.