• Linus Lüssing's avatar
    cfg80211/mac80211: add mesh_param "mesh_nolearn" to skip path discovery · e3718a61
    Linus Lüssing authored
    Currently, before being able to forward a packet between two 802.11s
    nodes, both a PLINK handshake is performed upon receiving a beacon and
    then later a PREQ/PREP exchange for path discovery is performed on
    demand upon receiving a data frame to forward.
    
    When running a mesh protocol on top of an 802.11s interface, like
    batman-adv, we do not need the multi-hop mesh routing capabilities of
    802.11s and usually set mesh_fwding=0. However, even with mesh_fwding=0
    the PREQ/PREP path discovery is still performed on demand. Even though
    in this scenario the next hop PREQ/PREP will determine is always the
    direct 11s neighbor node.
    
    The new mesh_nolearn parameter allows to skip the PREQ/PREP exchange in
    this scenario, leading to a reduced delay, reduced packet buffering and
    simplifies HWMP in general.
    
    mesh_nolearn is still rather conservative in that if the packet destination
    is not a direct 11s neighbor, it will fall back to PREQ/PREP path
    discovery.
    
    For normal, multi-hop 802.11s mesh routing it is usually not advisable
    to enable mesh_nolearn as a transmission to a direct but distant neighbor
    might be worse than reaching that same node via a more robust /
    higher throughput etc. multi-hop path.
    
    Cc: Sven Eckelmann <sven@narfation.org>
    Cc: Simon Wunderlich <sw@simonwunderlich.de>
    Signed-off-by: default avatarLinus Lüssing <ll@simonwunderlich.de>
    Link: https://lore.kernel.org/r/20200617073034.26149-1-linus.luessing@c0d3.blue
    [fix nl80211 policy to range 0/1 only]
    Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
    e3718a61
debugfs_netdev.c 23.9 KB