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https://git.kernel.org/pub/scm/network/wireless/iwd.git
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89 lines
4.2 KiB
Plaintext
89 lines
4.2 KiB
Plaintext
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IWD
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===
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- IWD will start a scheduled scan to the interface if the hardware supports
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that feature. If the iwd closes or dies so that the kernel netlink socket
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is closed, then the scheduled scan is cancelled automatically if the kernel
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supports this. This is done by giving NL80211_ATTR_SOCKET_OWNER netlink
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attribute when initiating the scheduled scan.
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- IWD contains a network object that will contain a list of BSS that have the
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same SSID and security setting. From user point of view, we will connect to
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a certain SSID instead of connecting directly to a BSS. IWD will then pick
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the best BSS automatically from the BSS list when connecting to a SSID.
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The "best" BSS in this context is the BSS that has the highest signal strength.
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- IWD uses the DBus agent interface to query information from the user.
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The information asked include things like passphrase etc. The user can
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register only one agent to iwd. If the user does not respond in timely
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manner to the query, then the pending user request is cancelled after a
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timeout. The pending user request is also cancelled if user disconnects a
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pending connection attempt.
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- IWD supports the full RSN 4-Way Handshake for PTK generation. Support for
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handling the optional (second) RSN element from the AP is included.
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- IWD supports Pre-authentication from 802.11-2007. If the currently
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connected AP supports pre-authentication and iwd determines that a roam is
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required, then the pre-authentication process is kicked off. This is done
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using the current connection, running 802.1X over 0x88c7 protocol. This results
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in the creation of a new PMK which is cached by both the target and iwd. iwd
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can then roam onto the target AP using the cached PMK.
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- IWD supports Fast Transitions for fast roaming between access points. Only
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FT-over-Air (fastest option) is currently supported by iwd. Whenever iwd
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determines that a roam is required and a suitable target that supports fast
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transitions is available, iwd roams to the target AP using FT automatically.
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- IWD supports Radio Resource Management from 802.11k. In particular iwd
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can request and utilize Neighbor Reports. When iwd determines that a roam
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is required, iwd will try to obtain a Neighbor Report from the currently
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connected AP (using a special Action frame). This enables iwd to optimize
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the list of channels to scan in order to find a suitable target for roaming
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much quicker.
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Wireless monitor
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================
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Netlink monitor interface is created if it does not exist
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The iwmon utility automates netlink monitor creation by by using RTNL
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to find an existing netlink monitor interface, and in case it does not
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exist, create a new one. By default the netlink monitor interface is
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named 'nlmon'. Another name can be given with the '--interface'
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command line option.
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Once iwmon terminates, the netlink monitor interface is removed (in
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case iwmon created it).
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HWSIM
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=====
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The radio id from kernel mac80211_hwsim module is parsed properly in
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hwsim. The radio id is not returned as HWSIM_ATTR_RADIO_ID but instead
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it is returned in error message. If the error code > 0, then that means
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the radio id. If the error code < 0, then that indicates a real error.
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The hwsim uses new HWSIM_ATTR_DESTROY_RADIO_ON_CLOSE flag attribute to
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tell the kernel that when the hwsim process dies, the radios it created
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should be removed. For testing tools it is beneficial if the newly
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created radio could be bound to the lifetime of the netlink socket.
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Alternatively, using the hwsim '-k (--keep)' command line option instructs
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hwsim to not destroy the created radio automatically.
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The hwsim is using HWSIM_CMD_NEW_RADIO to create a new radio. When the
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radio has been created, the kernel will return the used radio id and
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parameters in a HWSIM_CMD_NEW_RADIO multicast event that is sent in
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"config" netlink multicast group. The command HWSIM_CMD_DEL_RADIO is sent
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by kernel when a hwsim radio is deleted. In this case the deleted
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radio id is sent to "config" netlink multicast group.
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hwsim can list radios by sending a HWSIM_CMD_GET_RADIO with the attribute
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HWSIM_ATTR_RADIO_ID containing the desired radio id. If no radio id is
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given on the command line, a dump of all radios is requested from the
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kernel. The attributes returned are identical to those sent to the
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'config' multicast group when creating a radio.
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