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232b928974
Part of making all netlink monitoring code optional. Updates #17311 (how I got started down this path) Updates #12614 Change-Id: Ic80d8a7a44dc261c4b8678b3c2241c3b3778370d Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build linux && !android
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package linkspeed
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import (
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"github.com/mdlayher/genetlink"
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"github.com/mdlayher/netlink"
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"github.com/tailscale/wireguard-go/tun"
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"golang.org/x/sys/unix"
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"tailscale.com/net/tstun"
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)
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func init() {
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tstun.HookSetLinkAttrs.Set(setLinkAttrs)
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}
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// setLinkSpeed sets the advertised link speed of the TUN interface.
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func setLinkSpeed(iface tun.Device, mbps int) error {
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name, err := iface.Name()
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if err != nil {
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return err
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}
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conn, err := genetlink.Dial(&netlink.Config{Strict: true})
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if err != nil {
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return err
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}
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defer conn.Close()
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f, err := conn.GetFamily(unix.ETHTOOL_GENL_NAME)
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if err != nil {
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return err
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}
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ae := netlink.NewAttributeEncoder()
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ae.Nested(unix.ETHTOOL_A_LINKMODES_HEADER, func(nae *netlink.AttributeEncoder) error {
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nae.String(unix.ETHTOOL_A_HEADER_DEV_NAME, name)
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return nil
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})
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ae.Uint32(unix.ETHTOOL_A_LINKMODES_SPEED, uint32(mbps))
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b, err := ae.Encode()
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if err != nil {
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return err
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}
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_, err = conn.Execute(
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genetlink.Message{
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Header: genetlink.Header{
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Command: unix.ETHTOOL_MSG_LINKMODES_SET,
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Version: unix.ETHTOOL_GENL_VERSION,
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},
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Data: b,
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},
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f.ID,
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netlink.Request|netlink.Acknowledge,
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)
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return err
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}
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// setLinkAttrs sets up link attributes that can be queried by external tools.
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// Its failure is non-fatal to interface bringup.
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func setLinkAttrs(iface tun.Device) error {
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// By default the link speed is 10Mbps, which is easily exceeded and causes monitoring tools to complain (#3933).
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return setLinkSpeed(iface, unix.SPEED_UNKNOWN)
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}
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