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/**
@page vsa Vendor-Specific Action Frames

Vendor-specific action frames can be transmitted if the interface is configured in Raw mode.
Vendor-specific action frames are transmitted the same way that data frames are transmitted.
A packet with an 802.11 header is constructed, and the frame control field of the 802.11
header must be set to indicate that the packet is a management frame and an action frame.
This packet is sent to the host driver via the raw socket. The TX control header can be
used to specify parameters such as MCS and transmit power.

To send a vendor-specific action frame with the sample application, run

<tt>dsrc_tx -v</tt>

Vendor-specific action frames are received via netlink sockets and not via the raw socket
used by data packets. To receive vendor-specific action frames, the application must open
a generic netlink socket and register to receive vendor-specific action frames from the
appropriate interface by issuing a NL80211_CMD_REGISTER_FRAME message. The
NL80211_ATTR_FRAME_MATCH attribute is set to 127 to indicate vendor-specific actions.
After the netlink socket is registered to receive vendor-specific action frames,
these frames will be delivered to the application via the netlink socket
in a NL80211_CMD_FRAME message. In this message, the entire frame, including the 802.11
header, is in the NL80211_ATTR_FRAME attribute. The NL80211_ATTR_WIPHY_FREQ contains the
frequency on which the frame was received. The NL80211_ATTR_RX_SIGNAL_DBM attribute contains
the received signal strength in mBm units.

To receive vendor-specific action frames with the sample application, run

<tt>dsrc_config -c rx_vsa</tt>
*/