mirror of https://github.com/k3s-io/k3s
65 lines
1.3 KiB
Go
65 lines
1.3 KiB
Go
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package arping
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import (
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"errors"
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"fmt"
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"net"
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)
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func findIPInNetworkFromIface(dstIP net.IP, iface net.Interface) (net.IP, error) {
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addrs, err := iface.Addrs()
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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 addrs {
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if ipnet, ok := a.(*net.IPNet); ok {
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if ipnet.Contains(dstIP) {
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return ipnet.IP, nil
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}
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}
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}
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return nil, fmt.Errorf("iface: '%s' can't reach ip: '%s'", iface.Name, dstIP)
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}
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func findUsableInterfaceForNetwork(dstIP net.IP) (*net.Interface, error) {
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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isDown := func(iface net.Interface) bool {
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return iface.Flags&1 == 0
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}
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hasAddressInNetwork := func(iface net.Interface) bool {
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if _, err := findIPInNetworkFromIface(dstIP, iface); err != nil {
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return false
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}
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return true
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}
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verboseLog.Println("search usable interface")
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logIfaceResult := func(msg string, iface net.Interface) {
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verboseLog.Printf("%10s: %6s %18s %s", msg, iface.Name, iface.HardwareAddr, iface.Flags)
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}
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for _, iface := range ifaces {
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if isDown(iface) {
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logIfaceResult("DOWN", iface)
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continue
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}
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if !hasAddressInNetwork(iface) {
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logIfaceResult("OTHER NET", iface)
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continue
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}
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logIfaceResult("USABLE", iface)
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return &iface, nil
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}
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return nil, errors.New("no usable interface found")
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}
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