mirror of
https://github.com/prometheus/node_exporter.git
synced 2024-12-22 16:36:07 +01:00
480 lines
12 KiB
Go
480 lines
12 KiB
Go
//+build linux
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package wifi
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import (
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"bytes"
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"errors"
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"net"
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"os"
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"time"
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"unicode/utf8"
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"github.com/mdlayher/genetlink"
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"github.com/mdlayher/netlink"
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"github.com/mdlayher/netlink/nlenc"
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"github.com/mdlayher/wifi/internal/nl80211"
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)
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// Errors which may occur when interacting with generic netlink.
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var (
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errInvalidCommand = errors.New("invalid generic netlink response command")
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errInvalidFamilyVersion = errors.New("invalid generic netlink response family version")
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)
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var _ osClient = &client{}
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// A client is the Linux implementation of osClient, which makes use of
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// netlink, generic netlink, and nl80211 to provide access to WiFi device
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// actions and statistics.
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type client struct {
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c *genetlink.Conn
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familyID uint16
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familyVersion uint8
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}
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// newClient dials a generic netlink connection and verifies that nl80211
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// is available for use by this package.
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func newClient() (*client, error) {
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c, err := genetlink.Dial(nil)
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if err != nil {
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return nil, err
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}
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return initClient(c)
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}
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func initClient(c *genetlink.Conn) (*client, error) {
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family, err := c.GetFamily(nl80211.GenlName)
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if err != nil {
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// Ensure the genl socket is closed on error to avoid leaking file
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// descriptors.
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_ = c.Close()
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return nil, err
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}
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return &client{
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c: c,
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familyID: family.ID,
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familyVersion: family.Version,
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}, nil
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}
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// Close closes the client's generic netlink connection.
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func (c *client) Close() error {
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return c.c.Close()
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}
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// Interfaces requests that nl80211 return a list of all WiFi interfaces present
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// on this system.
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func (c *client) Interfaces() ([]*Interface, error) {
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// Ask nl80211 to dump a list of all WiFi interfaces
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req := genetlink.Message{
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Header: genetlink.Header{
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Command: nl80211.CmdGetInterface,
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Version: c.familyVersion,
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},
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}
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flags := netlink.HeaderFlagsRequest | netlink.HeaderFlagsDump
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msgs, err := c.c.Execute(req, c.familyID, flags)
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if err != nil {
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return nil, err
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}
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if err := c.checkMessages(msgs, nl80211.CmdNewInterface); err != nil {
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return nil, err
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}
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return parseInterfaces(msgs)
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}
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// BSS requests that nl80211 return the BSS for the specified Interface.
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func (c *client) BSS(ifi *Interface) (*BSS, error) {
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b, err := netlink.MarshalAttributes(ifi.idAttrs())
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if err != nil {
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return nil, err
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}
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// Ask nl80211 to retrieve BSS information for the interface specified
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// by its attributes
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req := genetlink.Message{
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Header: genetlink.Header{
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Command: nl80211.CmdGetScan,
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Version: c.familyVersion,
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},
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Data: b,
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}
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flags := netlink.HeaderFlagsRequest | netlink.HeaderFlagsDump
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msgs, err := c.c.Execute(req, c.familyID, flags)
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if err != nil {
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return nil, err
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}
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if err := c.checkMessages(msgs, nl80211.CmdNewScanResults); err != nil {
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return nil, err
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}
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return parseBSS(msgs)
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}
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// StationInfo requests that nl80211 return all station info for the specified
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// Interface.
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func (c *client) StationInfo(ifi *Interface) ([]*StationInfo, error) {
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b, err := netlink.MarshalAttributes(ifi.idAttrs())
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if err != nil {
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return nil, err
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}
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// Ask nl80211 to retrieve station info for the interface specified
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// by its attributes
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req := genetlink.Message{
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Header: genetlink.Header{
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// From nl80211.h:
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// * @NL80211_CMD_GET_STATION: Get station attributes for station identified by
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// * %NL80211_ATTR_MAC on the interface identified by %NL80211_ATTR_IFINDEX.
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Command: nl80211.CmdGetStation,
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Version: c.familyVersion,
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},
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Data: b,
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}
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flags := netlink.HeaderFlagsRequest | netlink.HeaderFlagsDump
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msgs, err := c.c.Execute(req, c.familyID, flags)
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if err != nil {
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return nil, err
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}
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if len(msgs) == 0 {
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return nil, os.ErrNotExist
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}
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stations := make([]*StationInfo, len(msgs))
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for i := range msgs {
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if err := c.checkMessages(msgs, nl80211.CmdNewStation); err != nil {
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return nil, err
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}
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if stations[i], err = parseStationInfo(msgs[i].Data); err != nil {
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return nil, err
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}
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}
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return stations, nil
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}
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// checkMessages verifies that response messages from generic netlink contain
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// the command and family version we expect.
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func (c *client) checkMessages(msgs []genetlink.Message, command uint8) error {
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for _, m := range msgs {
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if m.Header.Command != command {
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return errInvalidCommand
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}
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if m.Header.Version != c.familyVersion {
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return errInvalidFamilyVersion
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}
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}
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return nil
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}
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// parseInterfaces parses zero or more Interfaces from nl80211 interface
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// messages.
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func parseInterfaces(msgs []genetlink.Message) ([]*Interface, error) {
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ifis := make([]*Interface, 0, len(msgs))
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for _, m := range msgs {
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attrs, err := netlink.UnmarshalAttributes(m.Data)
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if err != nil {
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return nil, err
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}
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var ifi Interface
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if err := (&ifi).parseAttributes(attrs); err != nil {
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return nil, err
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}
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ifis = append(ifis, &ifi)
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}
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return ifis, nil
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}
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// idAttrs returns the netlink attributes required from an Interface to retrieve
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// more data about it.
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func (ifi *Interface) idAttrs() []netlink.Attribute {
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return []netlink.Attribute{
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{
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Type: nl80211.AttrIfindex,
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Data: nlenc.Uint32Bytes(uint32(ifi.Index)),
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},
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{
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Type: nl80211.AttrMac,
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Data: ifi.HardwareAddr,
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},
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}
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}
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// parseAttributes parses netlink attributes into an Interface's fields.
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func (ifi *Interface) parseAttributes(attrs []netlink.Attribute) error {
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for _, a := range attrs {
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switch a.Type {
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case nl80211.AttrIfindex:
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ifi.Index = int(nlenc.Uint32(a.Data))
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case nl80211.AttrIfname:
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ifi.Name = nlenc.String(a.Data)
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case nl80211.AttrMac:
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ifi.HardwareAddr = net.HardwareAddr(a.Data)
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case nl80211.AttrWiphy:
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ifi.PHY = int(nlenc.Uint32(a.Data))
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case nl80211.AttrIftype:
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// NOTE: InterfaceType copies the ordering of nl80211's interface type
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// constants. This may not be the case on other operating systems.
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ifi.Type = InterfaceType(nlenc.Uint32(a.Data))
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case nl80211.AttrWdev:
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ifi.Device = int(nlenc.Uint64(a.Data))
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case nl80211.AttrWiphyFreq:
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ifi.Frequency = int(nlenc.Uint32(a.Data))
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}
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}
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return nil
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}
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// parseBSS parses a single BSS with a status attribute from nl80211 BSS messages.
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func parseBSS(msgs []genetlink.Message) (*BSS, error) {
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for _, m := range msgs {
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attrs, err := netlink.UnmarshalAttributes(m.Data)
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if err != nil {
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return nil, err
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}
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for _, a := range attrs {
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if a.Type != nl80211.AttrBss {
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continue
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}
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nattrs, err := netlink.UnmarshalAttributes(a.Data)
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if err != nil {
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return nil, err
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}
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// The BSS which is associated with an interface will have a status
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// attribute
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if !attrsContain(nattrs, nl80211.BssStatus) {
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continue
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}
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var bss BSS
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if err := (&bss).parseAttributes(nattrs); err != nil {
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return nil, err
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}
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return &bss, nil
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}
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}
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return nil, os.ErrNotExist
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}
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// parseAttributes parses netlink attributes into a BSS's fields.
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func (b *BSS) parseAttributes(attrs []netlink.Attribute) error {
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for _, a := range attrs {
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switch a.Type {
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case nl80211.BssBssid:
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b.BSSID = net.HardwareAddr(a.Data)
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case nl80211.BssFrequency:
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b.Frequency = int(nlenc.Uint32(a.Data))
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case nl80211.BssBeaconInterval:
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// Raw value is in "Time Units (TU)". See:
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// https://en.wikipedia.org/wiki/Beacon_frame
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b.BeaconInterval = time.Duration(nlenc.Uint16(a.Data)) * 1024 * time.Microsecond
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case nl80211.BssSeenMsAgo:
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// * @NL80211_BSS_SEEN_MS_AGO: age of this BSS entry in ms
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b.LastSeen = time.Duration(nlenc.Uint32(a.Data)) * time.Millisecond
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case nl80211.BssStatus:
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// NOTE: BSSStatus copies the ordering of nl80211's BSS status
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// constants. This may not be the case on other operating systems.
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b.Status = BSSStatus(nlenc.Uint32(a.Data))
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case nl80211.BssInformationElements:
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ies, err := parseIEs(a.Data)
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if err != nil {
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return err
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}
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// TODO(mdlayher): return more IEs if they end up being generally useful
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for _, ie := range ies {
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switch ie.ID {
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case ieSSID:
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b.SSID = decodeSSID(ie.Data)
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}
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}
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}
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}
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return nil
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}
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// parseStationInfo parses StationInfo attributes from a byte slice of
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// netlink attributes.
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func parseStationInfo(b []byte) (*StationInfo, error) {
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attrs, err := netlink.UnmarshalAttributes(b)
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if err != nil {
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return nil, err
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}
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var info StationInfo
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for _, a := range attrs {
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switch a.Type {
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case nl80211.AttrMac:
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info.HardwareAddr = net.HardwareAddr(a.Data)
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case nl80211.AttrStaInfo:
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nattrs, err := netlink.UnmarshalAttributes(a.Data)
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if err != nil {
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return nil, err
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}
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if err := (&info).parseAttributes(nattrs); err != nil {
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return nil, err
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}
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// nl80211.AttrStaInfo is last attibute we are interested in
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return &info, nil
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default:
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// The other attributes that are returned here appear
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// nl80211.AttrIfindex, nl80211.AttrGeneration
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// No need to parse them for now.
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continue
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}
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}
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// No station info found
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return nil, os.ErrNotExist
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}
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// parseAttributes parses netlink attributes into a StationInfo's fields.
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func (info *StationInfo) parseAttributes(attrs []netlink.Attribute) error {
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for _, a := range attrs {
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switch a.Type {
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case nl80211.StaInfoConnectedTime:
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// Though nl80211 does not specify, this value appears to be in seconds:
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// * @NL80211_STA_INFO_CONNECTED_TIME: time since the station is last connected
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info.Connected = time.Duration(nlenc.Uint32(a.Data)) * time.Second
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case nl80211.StaInfoInactiveTime:
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// * @NL80211_STA_INFO_INACTIVE_TIME: time since last activity (u32, msecs)
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info.Inactive = time.Duration(nlenc.Uint32(a.Data)) * time.Millisecond
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case nl80211.StaInfoRxBytes64:
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info.ReceivedBytes = int(nlenc.Uint64(a.Data))
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case nl80211.StaInfoTxBytes64:
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info.TransmittedBytes = int(nlenc.Uint64(a.Data))
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case nl80211.StaInfoSignal:
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// * @NL80211_STA_INFO_SIGNAL: signal strength of last received PPDU (u8, dBm)
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// Should just be cast to int8, see code here: https://git.kernel.org/pub/scm/linux/kernel/git/jberg/iw.git/tree/station.c#n378
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info.Signal = int(int8(a.Data[0]))
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case nl80211.StaInfoRxPackets:
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info.ReceivedPackets = int(nlenc.Uint32(a.Data))
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case nl80211.StaInfoTxPackets:
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info.TransmittedPackets = int(nlenc.Uint32(a.Data))
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case nl80211.StaInfoTxRetries:
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info.TransmitRetries = int(nlenc.Uint32(a.Data))
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case nl80211.StaInfoTxFailed:
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info.TransmitFailed = int(nlenc.Uint32(a.Data))
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case nl80211.StaInfoBeaconLoss:
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info.BeaconLoss = int(nlenc.Uint32(a.Data))
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case nl80211.StaInfoRxBitrate, nl80211.StaInfoTxBitrate:
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rate, err := parseRateInfo(a.Data)
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if err != nil {
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return err
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}
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// TODO(mdlayher): return more statistics if they end up being
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// generally useful
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switch a.Type {
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case nl80211.StaInfoRxBitrate:
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info.ReceiveBitrate = rate.Bitrate
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case nl80211.StaInfoTxBitrate:
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info.TransmitBitrate = rate.Bitrate
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}
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}
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// Only use 32-bit counters if the 64-bit counters are not present.
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// If the 64-bit counters appear later in the slice, they will overwrite
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// these values.
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if info.ReceivedBytes == 0 && a.Type == nl80211.StaInfoRxBytes {
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info.ReceivedBytes = int(nlenc.Uint32(a.Data))
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}
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if info.TransmittedBytes == 0 && a.Type == nl80211.StaInfoTxBytes {
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info.TransmittedBytes = int(nlenc.Uint32(a.Data))
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}
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}
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return nil
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}
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// rateInfo provides statistics about the receive or transmit rate of
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// an interface.
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type rateInfo struct {
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// Bitrate in bits per second.
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Bitrate int
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}
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// parseRateInfo parses a rateInfo from netlink attributes.
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func parseRateInfo(b []byte) (*rateInfo, error) {
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attrs, err := netlink.UnmarshalAttributes(b)
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if err != nil {
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return nil, err
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}
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var info rateInfo
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for _, a := range attrs {
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switch a.Type {
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case nl80211.RateInfoBitrate32:
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info.Bitrate = int(nlenc.Uint32(a.Data))
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}
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// Only use 16-bit counters if the 32-bit counters are not present.
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// If the 32-bit counters appear later in the slice, they will overwrite
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// these values.
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if info.Bitrate == 0 && a.Type == nl80211.RateInfoBitrate {
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info.Bitrate = int(nlenc.Uint16(a.Data))
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}
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}
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// Scale bitrate to bits/second as base unit instead of 100kbits/second.
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// * @NL80211_RATE_INFO_BITRATE: total bitrate (u16, 100kbit/s)
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info.Bitrate *= 100 * 1000
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return &info, nil
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}
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// attrsContain checks if a slice of netlink attributes contains an attribute
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// with the specified type.
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func attrsContain(attrs []netlink.Attribute, typ uint16) bool {
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for _, a := range attrs {
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if a.Type == typ {
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return true
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}
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}
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return false
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}
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// decodeSSID safely parses a byte slice into UTF-8 runes, and returns the
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// resulting string from the runes.
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func decodeSSID(b []byte) string {
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buf := bytes.NewBuffer(nil)
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for len(b) > 0 {
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r, size := utf8.DecodeRune(b)
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b = b[size:]
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buf.WriteRune(r)
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}
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return buf.String()
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}
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