On Thursday 26 Jan 2012, Victor Goldenshtein wrote: > This patch set (with nl/cfg/mac80211 patch series) adds support for DFS > (Dynamic Frequency Selection) according 802.11h. > > > Main idea > =================== > > DFS master algorithm is implemented in the hostapd, while nl/cfg/mac80211 > will pipe relevant commands/events to the driver/hostapd. As I understand it hostapd is not involved in mesh (802.11s) networks, so how does this integrate there? As I understand it 802.11s is entirely done in the kernel. David > > Based on the assumption that the device/driver supports radar interference > detection i.e., it is capable to generate radar_detected event by using > different pattern detection techniques: > > > 1. Pattern detection in the HW: the device generates 'radar_detected' > event. 2. Pattern detection in the driver: the driver receives radar > pulses from the device and generates 'radar detected' event. > > > Main DFS procedures > =================== > > 1. Hostapd gets driver's dfs capabilities. > > 2. If 80211h is enabled in the hostapd.conf and the driver supports one of > the above radar detection techniques, hostapd may use DFS channels. > > 3. Hostapd selects an operational channel (default from hostapd.conf), if > selected channel is a DFS channel, hostapd sends start_radar_detection > command to the device/driver which starts monitoring for radar > interference while hostapd sets a timer for a CAC (Channel Availability > Check) time, which is 60 seconds. > > 4. As CAC timer expires and no radar has been detected, hostapd may > continue with the init flow, otherwise if interference is detected hostapd > selects another channel (random selection) and repeats the CAC on the new > channel (in case the new channel is also a DFS channel), while the > original channel is added to a "black list" for a period of > ''No-Occupancy'' time (time that the channel can't be used/selected). > > 5. While using the channel the device/driver continuously monitors for > potential radar interference. If interference is detected hostapd notified > with 'radar detected' event, which selects a new channel and triggers a > channel switch procedure, if the new channel is also a DFS channel, > hostapd performs the CAC test, once it's successfully passed hostapd > instructs the driver to initiate the transmission on the channel. > > > Victor Goldenshtein (7): > hostapd: implement dfs drv ops functions > hostapd: add channel switch ability > hostapd: add dfs events > hostapd: add dfs support into interface init flow > nl80211: add support to enable TX on oper-channel > nl80211: add channel switch command/event > nl80211: add start radar detection command/event > > hostapd/config_file.c | 10 +++ > src/ap/ap_config.h | 4 + > src/ap/ap_drv_ops.c | 34 +++++++++ > src/ap/ap_drv_ops.h | 4 + > src/ap/beacon.c | 16 ++++ > src/ap/drv_callbacks.c | 40 +++++++++++ > src/ap/hostapd.c | 158 > ++++++++++++++++++++++++++++++++++++++++-- src/ap/hostapd.h | > 10 +++ > src/ap/hw_features.c | 48 ++++++++++--- > src/ap/hw_features.h | 10 +++ > src/ap/ieee802_11.c | 116 +++++++++++++++++++++++++++++++ > src/ap/ieee802_11.h | 4 + > src/drivers/driver.h | 87 +++++++++++++++++++++++- > src/drivers/driver_common.c | 2 + > src/drivers/driver_nl80211.c | 125 +++++++++++++++++++++++++++++++++ > src/utils/eloop.c | 4 + > src/utils/eloop.h | 7 ++ > 17 files changed, 662 insertions(+), 17 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
