What is the name of the Linux kernel's wireless MAC layer subsystem? It is mac80211.
mac80211 is the kernel's shared framework for SoftMAC, or half-MAC, wireless hardware. In a SoftMAC design, the device or firmware handles timing-critical radio work, while the host kernel performs much of the 802.11 protocol processing. The framework supplies common support for tasks such as frame handling, management operations, transmission queues, power saving, rate control, and monitor mode.
The name refers to the IEEE 802.11 wireless LAN family and its medium-access-control layer. mac80211 is not a particular Wi-Fi chipset driver; drivers such as ath9k use the framework rather than reimplementing the entire wireless stack.
The distractors are neighboring pieces of Linux wireless infrastructure. cfg80211 provides the configuration API, while nl80211 is the netlink interface used for kernel–userspace communication. iwlwifi is a driver for Intel wireless hardware. Those components interact with mac80211, but none is the kernel's general SoftMAC MAC-layer framework.