54 lines
1.6 KiB
Go
54 lines
1.6 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package monitor
|
|
|
|
import (
|
|
"fmt"
|
|
"time"
|
|
|
|
"github.com/mdlayher/netlink"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
// nlConn wraps a *netlink.Conn and returns a monitor.Message
|
|
// instead of a netlink.Message. Currently, messages are discarded,
|
|
// but down the line, when messages trigger different logic depending
|
|
// on the type of event, this provides the capability of handling
|
|
// each architecture-specific message in a generic fashion.
|
|
type nlConn struct {
|
|
conn *netlink.Conn
|
|
}
|
|
|
|
func newOSMon() (osMon, error) {
|
|
conn, err := netlink.Dial(unix.NETLINK_ROUTE, &netlink.Config{
|
|
// IPv4 address and route changes. Routes get us most of the
|
|
// events of interest, but we need address as well to cover
|
|
// things like DHCP deciding to give us a new address upon
|
|
// renewal - routing wouldn't change, but all reachability
|
|
// would.
|
|
Groups: unix.RTMGRP_IPV4_IFADDR | unix.RTMGRP_IPV4_ROUTE,
|
|
})
|
|
if err != nil {
|
|
return nil, fmt.Errorf("dialing netlink socket: %v", err)
|
|
}
|
|
return &nlConn{conn}, nil
|
|
}
|
|
|
|
func (c *nlConn) Close() error {
|
|
c.conn.SetDeadline(time.Unix(0, 0)) // abort any Receive in flight
|
|
return c.conn.Close()
|
|
}
|
|
|
|
func (c *nlConn) Receive() (message, error) {
|
|
// currently ignoring the message
|
|
_, err := c.conn.Receive()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// TODO(]|[): this is where the NetLink-specific message would
|
|
// get converted into a "standard" event message and returned.
|
|
return nil, nil
|
|
}
|