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mac80211-next: rtnetlink wifi simulation device
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This device takes over an existing network device and produces a
new one that appears like a wireless connection, returning enough canned
responses to nl80211 to satisfy a standard connection manager. If
necessary, it can also be set up one step removed from an existing
network device, such as through a vlan/80211Q or macvlan connection to
not disrupt the existing network interface.

To use it to wrap a bare ethernet connection:

ip link add link eth0 name wlan0 type virt_wifi

You may have to rename or otherwise hide the eth0 from your connection
manager, as the original network link will become unusuable and only
the wireless wrapper will be functional. This can also be combined with
vlan or macvlan links on top of eth0 to share the network between
distinct links, but that requires support outside the machine for
accepting vlan-tagged packets or packets from multiple MAC addresses.

This is being used for Google's Remote Android Virtual Device project,
which runs Android devices in virtual machines. The standard network
interfaces provided inside the virtual machines are all ethernet.
However, Android is not interested in ethernet devices and would rather
connect to a wireless interface. This patch allows the virtual machine
guest to treat one of its network connections as wireless rather than
ethernet, satisfying Android's network connection requirements.

We believe this is a generally useful driver for simulating wireless
network connections in other environments where a wireless connection is
desired by some userspace process but is not available.

This is distinct from other testing efforts such as mac80211_hwsim by
being a cfg80211 device instead of mac80211 device, allowing straight
pass-through on the data plane instead of forcing packaging of ethernet
data into mac80211 frames.

Signed-off-by: A. Cody Schuffelen <[email protected]>
Acked-by: Alistair Strachan <[email protected]>
Acked-by: Greg Hartman <[email protected]>
Acked-by: Tristan Muntsinger <[email protected]>
[make it a tristate]
Signed-off-by: Johannes Berg <[email protected]>
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Databean authored and jmberg-intel committed Dec 5, 2018
1 parent cc1068e commit c7cdba3
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7 changes: 7 additions & 0 deletions drivers/net/wireless/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -114,4 +114,11 @@ config USB_NET_RNDIS_WLAN

If you choose to build a module, it'll be called rndis_wlan.

config VIRT_WIFI
tristate "Wifi wrapper for ethernet drivers"
depends on CFG80211
---help---
This option adds support for ethernet connections to appear as if they
are wifi connections through a special rtnetlink device.

endif # WLAN
2 changes: 2 additions & 0 deletions drivers/net/wireless/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -27,3 +27,5 @@ obj-$(CONFIG_PCMCIA_WL3501) += wl3501_cs.o
obj-$(CONFIG_USB_NET_RNDIS_WLAN) += rndis_wlan.o

obj-$(CONFIG_MAC80211_HWSIM) += mac80211_hwsim.o

obj-$(CONFIG_VIRT_WIFI) += virt_wifi.o
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