These commnds are mesh version of PMKSA_GET/ADD commands. So the usage
and security risk is similar to them. Refer to
commit 3459381dd260e15e7bf768a75cb0b799cc1db33a ('External persistent
storage for PMKSA cache entries') also.
The MESH_PMKSA_GET command requires peer MAC address or "any" as an
argument and outputs appropriate stored PMKSA cache. And the
MESH_PMKSA_ADD command receives an output of MESH_PMKSA_GET and re-store
the PMKSA cache into wpa_supplicant. By using re-stored PMKSA cache,
wpa_supplicant can skip commit message creation which can use
significant CPU resources.
The output of the MESH_PMKSA_GET command uses the following format:
<BSSID> <PMKID> <PMK> <expiration in seconds>