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Initial Commit
This commit is contained in:
147
pkg/config/config.go
Normal file
147
pkg/config/config.go
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@ -0,0 +1,147 @@
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package config
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import (
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_ "embed"
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"encoding/json"
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"fmt"
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"net"
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"os"
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"path/filepath"
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"strings"
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"git.cryptic.systems/volker.raschek/dyndns-client/pkg/types"
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log "github.com/sirupsen/logrus"
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)
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//go:embed config.json
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var defaultConfig string
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// GetDefaultConfiguration returns a default configuration
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func GetDefaultConfiguration() (*types.Config, error) {
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cnf := new(types.Config)
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jsonDecoder := json.NewDecoder(strings.NewReader(defaultConfig))
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err := jsonDecoder.Decode(cnf)
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if err != nil {
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return nil, fmt.Errorf("failed to decode default config: %w", err)
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}
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defaultInterface, err := getDefaultInterfaceByIP()
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if err != nil {
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return nil, err
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}
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cnf.Ifaces = []string{defaultInterface.Name}
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return cnf, nil
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}
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// Read config from a file
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func Read(cnfFile string) (*types.Config, error) {
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// Load burned in configuration if config not available
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if _, err := os.Stat(cnfFile); os.IsNotExist(err) {
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if err := os.MkdirAll(filepath.Dir(cnfFile), 0755); err != nil {
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return nil, fmt.Errorf("failed to create directory: %w", err)
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}
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cnf, err := GetDefaultConfiguration()
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if err != nil {
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return nil, err
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}
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err = cnf.Validate()
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if err != nil {
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return nil, err
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}
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log.Infof("use embedded configuration")
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return cnf, nil
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}
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f, err := os.Open(cnfFile)
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if err != nil {
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return nil, fmt.Errorf("failed to open file: %w", err)
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}
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defer f.Close()
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cnf := new(types.Config)
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jsonDecoder := json.NewDecoder(f)
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err = jsonDecoder.Decode(cnf)
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if err != nil {
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return nil, fmt.Errorf("failed to decode json: %w", err)
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}
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for _, iface := range cnf.Ifaces {
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if _, err := net.InterfaceByName(iface); err != nil {
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return nil, fmt.Errorf("unknown interface: %v", iface)
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}
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}
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err = cnf.Validate()
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if err != nil {
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return nil, err
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}
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log.Infof("use configuration from file %v", cnfFile)
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return cnf, nil
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}
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// Write config into a file
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func Write(cnf *types.Config, cnfFile string) error {
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if _, err := os.Stat(filepath.Dir(cnfFile)); os.IsNotExist(err) {
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err := os.MkdirAll(filepath.Dir(cnfFile), 0755)
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if err != nil {
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return err
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}
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}
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f, err := os.Create(cnfFile)
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if err != nil {
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return fmt.Errorf("failed to create file %v: %v", cnfFile, err)
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}
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defer f.Close()
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jsonEncoder := json.NewEncoder(f)
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jsonEncoder.SetIndent("", " ")
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err = jsonEncoder.Encode(cnf)
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if err != nil {
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return fmt.Errorf("failed to encode json: %w", err)
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}
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return nil
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}
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func getDefaultInterfaceByIP() (*net.Interface, error) {
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, fmt.Errorf("failed to fet network interfaces from kernel: %w", err)
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}
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defaultIP := getOutboundIP()
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for _, iface := range ifaces {
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addrs, err := iface.Addrs()
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if err != nil {
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return nil, fmt.Errorf("failed to list ip addresses for interface %v: %w", iface.Name, err)
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}
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for _, addr := range addrs {
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addrIP := strings.Split(addr.String(), "/")[0]
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if addrIP == defaultIP.String() {
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return &iface, nil
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}
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}
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}
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return nil, fmt.Errorf("no interface found fo ip address %v", defaultIP)
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}
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func getOutboundIP() net.IP {
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conn, err := net.Dial("udp", "8.8.8.8:80")
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if err != nil {
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log.Fatal(err)
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}
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defer conn.Close()
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localAddr := conn.LocalAddr().(*net.UDPAddr)
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return localAddr.IP
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}
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1
pkg/config/config.json
Normal file
1
pkg/config/config.json
Normal file
@ -0,0 +1 @@
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{}
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335
pkg/daemon/daemon.go
Normal file
335
pkg/daemon/daemon.go
Normal file
@ -0,0 +1,335 @@
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package daemon
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import (
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"context"
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"fmt"
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"net"
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"os"
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"os/signal"
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"regexp"
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"strings"
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"sync"
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"syscall"
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"time"
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"git.cryptic.systems/volker.raschek/dyndns-client/pkg/types"
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"git.cryptic.systems/volker.raschek/dyndns-client/pkg/updater"
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"github.com/asaskevich/govalidator"
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log "github.com/sirupsen/logrus"
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"github.com/vishvananda/netlink"
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)
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func Start(cnf *types.Config) {
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addrUpdates := make(chan netlink.AddrUpdate, 1)
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done := make(chan struct{}, 1)
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err := netlink.AddrSubscribeWithOptions(addrUpdates, done, netlink.AddrSubscribeOptions{
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ListExisting: true,
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})
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if err != nil {
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log.Fatalf("failed to subscribe netlink notifications from kernel: %v", err.Error())
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}
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interuptChannel := make(chan os.Signal, 1)
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signal.Notify(interuptChannel, syscall.SIGINT, syscall.SIGTERM)
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ctx := context.Background()
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daemonCtx, cancle := context.WithCancel(ctx)
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defer cancle()
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updaters, err := getUpdaterForEachZone(cnf)
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if err != nil {
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log.Fatalf("%v", err.Error())
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}
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if err := pruneRecords(daemonCtx, updaters, cnf.Zones); err != nil {
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log.Fatalf("%v", err.Error())
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}
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for {
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interfaces, err := netlink.LinkList()
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if err != nil {
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log.Fatal("%v", err.Error())
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}
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select {
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case update := <-addrUpdates:
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interfaceLogger := log.WithFields(log.Fields{
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"ip": update.LinkAddress.IP.String(),
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})
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// search interface by index
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iface, err := searchInterfaceByIndex(update.LinkIndex, interfaces)
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if err != nil {
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log.Errorf("%v", err.Error())
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continue
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}
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interfaceLogger = interfaceLogger.WithField("device", iface.Attrs().Name)
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var recordType string
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switch {
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case govalidator.IsIPv4(strings.TrimRight(update.LinkAddress.IP.String(), "/")):
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recordType = "A"
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case govalidator.IsIPv6(strings.TrimRight(update.LinkAddress.IP.String(), "/")):
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recordType = "AAAA"
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default:
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interfaceLogger.Error("failed to detect record type")
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continue
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}
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interfaceLogger = interfaceLogger.WithField("rr", recordType)
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interfaceLogger.Debug("receive kernel notification for interface")
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// filter out not configured interfaces
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if !matchInterfaces(iface.Attrs().Name, cnf.Ifaces) {
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interfaceLogger.Warn("interface is not part of the allowed interface list")
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continue
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}
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// filter out notification for a bad interface ip address, for example link-local-addresses
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if update.LinkAddress.IP.IsLoopback() || strings.HasPrefix(update.LinkAddress.IP.String(), "fe80") {
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interfaceLogger.Warn("interface is a loopback device or part of a loopback network")
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continue
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}
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// decide if trigger a add or delete event
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if update.NewAddr {
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err = addIPRecords(daemonCtx, interfaceLogger, updaters, cnf.Zones, recordType, update.LinkAddress.IP)
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if err != nil {
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interfaceLogger.Error(err.Error())
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}
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} else {
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err = removeIPRecords(daemonCtx, interfaceLogger, updaters, cnf.Zones, recordType, update.LinkAddress.IP)
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if err != nil {
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interfaceLogger.Error(err.Error())
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}
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}
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case killSignal := <-interuptChannel:
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log.Debugf("got signal: %v", killSignal)
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log.Debugf("daemon was killed by: %v", killSignal)
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return
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}
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}
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}
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func getUpdaterForEachZone(config *types.Config) (map[string]updater.Updater, error) {
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updaterCollection := make(map[string]updater.Updater)
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for zoneName, zone := range config.Zones {
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nsUpdater, err := updater.NewNSUpdate(zone.DNSServer, config.TSIGKeys[zone.TSIGKeyName])
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if err != nil {
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return nil, err
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}
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updaterCollection[zoneName] = nsUpdater
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}
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return updaterCollection, nil
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}
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func matchInterfaces(iface string, ifaces []string) bool {
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for _, i := range ifaces {
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if i == iface {
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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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func searchInterfaceByIndex(index int, interfaces []netlink.Link) (netlink.Link, error) {
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for _, iface := range interfaces {
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if iface.Attrs().Index == index {
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return iface, nil
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}
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}
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return nil, fmt.Errorf("can not find interface by index %v", index)
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}
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func addIPRecords(ctx context.Context, logEntry *log.Entry, updaters map[string]updater.Updater, zones map[string]*types.Zone, recordType string, ip net.IP) error {
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var (
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errorChannel = make(chan error, len(zones))
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wg = new(sync.WaitGroup)
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)
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hostname, err := os.Hostname()
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if err != nil {
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return fmt.Errorf("failed to get host name from kernel: %w", err)
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}
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hostname = strings.ToLower(hostname)
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if !verifyHostname(hostname) {
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return fmt.Errorf("host name not valid: %w", err)
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}
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for zoneName := range zones {
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wg.Add(1)
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go func(ctx context.Context, zoneName string, hostname string, recordType string, ip net.IP, wg *sync.WaitGroup) {
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zoneLogger := logEntry.WithFields(log.Fields{
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"zone": zoneName,
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"hostname": hostname,
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})
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defer wg.Done()
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pruneRecordCtx, cancle := context.WithTimeout(ctx, time.Second*15)
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defer cancle()
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fqdn := fmt.Sprintf("%v.%v", hostname, zoneName)
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err := updaters[zoneName].AddRecord(pruneRecordCtx, fqdn, 60, recordType, ip.String())
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if err != nil {
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errorChannel <- fmt.Errorf("failed to remove record type %v for %v: %v", recordType, fqdn, err.Error())
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return
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}
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zoneLogger.Info("dns-record successfully updated")
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}(ctx, zoneName, hostname, recordType, ip, wg)
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}
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wg.Wait()
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close(errorChannel)
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for err := range errorChannel {
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if err != nil {
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return err
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}
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}
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return nil
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}
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func pruneRecords(ctx context.Context, updaters map[string]updater.Updater, zones map[string]*types.Zone) error {
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var (
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errorChannel = make(chan error, len(zones))
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wg = new(sync.WaitGroup)
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)
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hostname, err := os.Hostname()
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if err != nil {
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return fmt.Errorf("failed to get host name from kernel: %w", err)
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}
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hostname = strings.ToLower(hostname)
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if !verifyHostname(hostname) {
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return fmt.Errorf("host name not valid: %w", err)
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}
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for zoneName := range zones {
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wg.Add(1)
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go func(zoneName string, hostname string, errorChannel chan<- error, wg *sync.WaitGroup) {
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defer wg.Done()
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pruneRecordCtx, cancle := context.WithTimeout(ctx, time.Second*15)
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defer cancle()
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fqdn := fmt.Sprintf("%v.%v", hostname, zoneName)
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err := updaters[zoneName].PruneRecords(pruneRecordCtx, fqdn)
|
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if err != nil {
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errorChannel <- fmt.Errorf("failed to prune %v: %v", fqdn, err)
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return
|
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}
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}(zoneName, hostname, errorChannel, wg)
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}
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|
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wg.Wait()
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close(errorChannel)
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|
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for err := range errorChannel {
|
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if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
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|
||||
return nil
|
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}
|
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|
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func removeIPRecords(ctx context.Context, logEntry *log.Entry, updaters map[string]updater.Updater, zones map[string]*types.Zone, recordType string, ip net.IP) error {
|
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|
||||
var (
|
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errorChannel = make(chan error, len(zones))
|
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wg = new(sync.WaitGroup)
|
||||
)
|
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|
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hostname, err := os.Hostname()
|
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if err != nil {
|
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return fmt.Errorf("failed to get host name from kernel: %w", err)
|
||||
}
|
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hostname = strings.ToLower(hostname)
|
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|
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if !verifyHostname(hostname) {
|
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return fmt.Errorf("host name not valid: %w", err)
|
||||
}
|
||||
|
||||
for zoneName := range zones {
|
||||
wg.Add(1)
|
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|
||||
go func(ctx context.Context, zoneName string, hostname string, recordType string, wg *sync.WaitGroup) {
|
||||
defer wg.Done()
|
||||
|
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zoneLogger := logEntry.WithFields(log.Fields{
|
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"zone": zoneName,
|
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"hostname": hostname,
|
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})
|
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|
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pruneRecordCtx, cancle := context.WithTimeout(ctx, time.Second*15)
|
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defer cancle()
|
||||
|
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fqdn := fmt.Sprintf("%v.%v", hostname, zoneName)
|
||||
|
||||
err := updaters[zoneName].DeleteRecord(pruneRecordCtx, fqdn, recordType)
|
||||
if err != nil {
|
||||
errorChannel <- fmt.Errorf("failed to remove record type %v for %v: %v", recordType, fqdn, err.Error())
|
||||
return
|
||||
}
|
||||
|
||||
zoneLogger.Info("dns-record successfully removed")
|
||||
|
||||
}(ctx, zoneName, hostname, recordType, wg)
|
||||
}
|
||||
|
||||
wg.Wait()
|
||||
close(errorChannel)
|
||||
|
||||
for err := range errorChannel {
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// verifyHostname returns a boolean if the hostname id valid. The hostname does
|
||||
// not contains any dot or local, localhost, localdomain.
|
||||
func verifyHostname(hostname string) bool {
|
||||
|
||||
if !validHostname.MatchString(hostname) {
|
||||
return false
|
||||
}
|
||||
|
||||
hostnames := []string{
|
||||
"local",
|
||||
"localhost",
|
||||
"localdomain",
|
||||
"orbisos",
|
||||
}
|
||||
|
||||
for i := range hostnames {
|
||||
if hostnames[i] == hostname {
|
||||
return false
|
||||
}
|
||||
}
|
||||
|
||||
return true
|
||||
}
|
||||
|
||||
var (
|
||||
validHostname = regexp.MustCompile(`^[a-zA-Z0-9]+([\-][a-zA-Z0-9]+)*$`)
|
||||
)
|
||||
42
pkg/types/config.go
Normal file
42
pkg/types/config.go
Normal file
@ -0,0 +1,42 @@
|
||||
package types
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
|
||||
"github.com/asaskevich/govalidator"
|
||||
)
|
||||
|
||||
type Config struct {
|
||||
Ifaces []string `json:"interfaces"`
|
||||
Zones map[string]*Zone `json:"zones"`
|
||||
TSIGKeys map[string]*TSIGKey `json:"tsig-keys"`
|
||||
}
|
||||
|
||||
func (c *Config) Validate() error {
|
||||
if len(c.Zones) <= 0 {
|
||||
return fmt.Errorf("no dns zones configured")
|
||||
}
|
||||
|
||||
if len(c.Ifaces) <= 0 {
|
||||
return fmt.Errorf("no interfaces configured")
|
||||
}
|
||||
|
||||
ZONE_LOOP:
|
||||
for _, zone := range c.Zones {
|
||||
if !govalidator.IsIP(zone.DNSServer) && !govalidator.IsDNSName(zone.DNSServer) {
|
||||
return fmt.Errorf("invalid dns server %v", zone.DNSServer)
|
||||
}
|
||||
|
||||
if !govalidator.IsDNSName(zone.Name) {
|
||||
return fmt.Errorf("invalid dns zone name %v", zone.Name)
|
||||
}
|
||||
|
||||
for _, tsigkey := range c.TSIGKeys {
|
||||
if tsigkey.Name == zone.TSIGKeyName {
|
||||
continue ZONE_LOOP
|
||||
}
|
||||
}
|
||||
return fmt.Errorf("no matching tsigkey found for zone %v", zone.Name)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
7
pkg/types/tsigkey.go
Normal file
7
pkg/types/tsigkey.go
Normal file
@ -0,0 +1,7 @@
|
||||
package types
|
||||
|
||||
type TSIGKey struct {
|
||||
Algorithm string `json:"algorithm"`
|
||||
Name string `json:"name"`
|
||||
Secret string `json:"secret"`
|
||||
}
|
||||
7
pkg/types/zone.go
Normal file
7
pkg/types/zone.go
Normal file
@ -0,0 +1,7 @@
|
||||
package types
|
||||
|
||||
type Zone struct {
|
||||
DNSServer string `json:"dns-server"`
|
||||
Name string `json:"name"`
|
||||
TSIGKeyName string `json:"tsig-key"`
|
||||
}
|
||||
72
pkg/updater/updater.go
Normal file
72
pkg/updater/updater.go
Normal file
@ -0,0 +1,72 @@
|
||||
package updater
|
||||
|
||||
import (
|
||||
"bufio"
|
||||
"bytes"
|
||||
"context"
|
||||
"fmt"
|
||||
"os/exec"
|
||||
"strings"
|
||||
|
||||
"git.cryptic.systems/volker.raschek/dyndns-client/pkg/types"
|
||||
)
|
||||
|
||||
type Updater interface {
|
||||
AddRecord(ctx context.Context, name string, ttl uint, recordType string, data string) error
|
||||
DeleteRecord(ctx context.Context, name string, recordType string) error
|
||||
PruneRecords(ctx context.Context, name string) error
|
||||
}
|
||||
|
||||
type NSUpdate struct {
|
||||
server string
|
||||
tsigKey *types.TSIGKey
|
||||
}
|
||||
|
||||
func (u *NSUpdate) AddRecord(ctx context.Context, name string, ttl uint, recordType string, data string) error {
|
||||
nsUpdateCmd := ""
|
||||
switch recordType {
|
||||
case "A", "AAAA":
|
||||
nsUpdateCmd = fmt.Sprintf("update add %v %v IN %v %v", name, ttl, recordType, data)
|
||||
case "TXT":
|
||||
nsUpdateCmd = fmt.Sprintf("update add %v %v IN %v \"%v\"", name, ttl, recordType, data)
|
||||
default:
|
||||
return fmt.Errorf("RecordType %v not supported", recordType)
|
||||
}
|
||||
|
||||
return u.execute(ctx, nsUpdateCmd)
|
||||
}
|
||||
|
||||
func (u *NSUpdate) DeleteRecord(ctx context.Context, name string, recordType string) error {
|
||||
nsUpdateCmd := fmt.Sprintf("update delete %v IN %v", name, recordType)
|
||||
return u.execute(ctx, nsUpdateCmd)
|
||||
}
|
||||
|
||||
func (u *NSUpdate) execute(ctx context.Context, nsUpdateCmd string) error {
|
||||
body := fmt.Sprintf("server %v\n%v\nsend\nquit", u.server, nsUpdateCmd)
|
||||
|
||||
errBuffer := new(bytes.Buffer)
|
||||
|
||||
cmd := exec.CommandContext(ctx, "nsupdate", "-y", fmt.Sprintf("%v:%v:%v", u.tsigKey.Algorithm, u.tsigKey.Name, u.tsigKey.Secret))
|
||||
// cmd.Stdout = os.Stdout
|
||||
cmd.Stderr = bufio.NewWriter(errBuffer)
|
||||
cmd.Stdin = strings.NewReader(body)
|
||||
|
||||
err := cmd.Run()
|
||||
if err != nil {
|
||||
return fmt.Errorf("nsupdate error %w: %v", err, errBuffer.String())
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (u *NSUpdate) PruneRecords(ctx context.Context, name string) error {
|
||||
nsUpdateCmd := fmt.Sprintf("update delete %v", name)
|
||||
return u.execute(ctx, nsUpdateCmd)
|
||||
}
|
||||
|
||||
func NewNSUpdate(server string, tsigKey *types.TSIGKey) (Updater, error) {
|
||||
return &NSUpdate{
|
||||
server: server,
|
||||
tsigKey: tsigKey,
|
||||
}, nil
|
||||
}
|
||||
Reference in New Issue
Block a user