Net 1603

dns/dns.go

@@ -0,0 +1,61 @@
+package dns
+
+import (
+ "errors"
+ "fmt"
+ "net"
+ "strings"
+
+ "github.com/gravitl/netmaker/models"
+ "github.com/miekg/dns"
+)
+
+type dnsRecord struct {
+ Name string
+ // Type of record, 1 for A, 5 for CNAME, 28 for AAAA
+ Type uint16
+ RData string
+}
+
+func newDNSRecord(name string, t uint16, dest string) dnsRecord {
+ return dnsRecord{
+ Name: name,
+ Type: t,
+ RData: dest,
+ }
+}
+
+func buildDNSEntryKey(name string, t uint16) string {
+ return fmt.Sprintf("%s.%d", name, t)
+}
+
+func SyncDNS(dnsEntries []models.DNSEntry) error {
+ if len(dnsEntries) == 0 {
+ return errors.New("no DNS entry")
+ }
+
+ GetDNSResolverInstance().DnsEntriesCacheStore = make(map[string]dns.RR)
+
+ for _, v := range dnsEntries {
+
+ if !strings.HasSuffix(v.Name, v.Network) {
+ continue
+ }
+
+ if v.Address != "" {
+ if ipv4 := net.ParseIP(v.Address).To4(); ipv4 != nil {
+ r := newDNSRecord(v.Name, dns.TypeA, v.Address)
+ GetDNSResolverInstance().RegisterA(r)
+ }
+ }
+
+ if v.Address6 != "" {
+ if ipv4 := net.ParseIP(v.Address6).To4(); ipv4 == nil {
+ r := newDNSRecord(v.Name, dns.TypeAAAA, v.Address6)
+ GetDNSResolverInstance().RegisterAAAA(r)
+ }
+ }
+ }
+
+ return nil
+}

dns/listener.go

@@ -0,0 +1,76 @@
+package dns
+
+import (
+ "context"
+ "sync"
+ "time"
+
+ "github.com/gravitl/netclient/config"
+ "github.com/miekg/dns"
+ "golang.org/x/exp/slog"
+)
+
+var dnsMutex = sync.Mutex{} // used to mutex functions of the DNS
+
+type DNSServer struct {
+ DnsServer *dns.Server
+ AddrStr string
+}
+
+var dnsServer *DNSServer
+
+func init() {
+ dnsServer = &DNSServer{}
+}
+
+// GetInstance
+func GetDNSServerInstance() *DNSServer {
+ return dnsServer
+}
+
+func (dnsServer *DNSServer) Start() {
+ dnsMutex.Lock()
+ defer dnsMutex.Unlock()
+ if dnsServer.DnsServer != nil {
+ return
+ }
+ lIp := config.Netclient().Host.EndpointIP.String() + ":53"
+ if config.Netclient().Host.EndpointIP == nil {
+ lIp = "[" + config.Netclient().Host.EndpointIPv6.String() + "]:53"
+ }
+ if config.Netclient().Host.EndpointIPv6 == nil && config.Netclient().Host.EndpointIP == nil {
+ lIp = ":5353"
+ }
+
+ dns.HandleFunc(".", handleDNSRequest)
+
+ srv := &dns.Server{
+ Net: "udp",
+ Addr: lIp,
+ }
+
+ go func() {
+ err := srv.ListenAndServe()
+ if err != nil {
+ slog.Error("error in starting dns server", "error", lIp, err.Error())
+ }
+ }()
+
+ slog.Info("DNS server listens on: ", "Info", lIp)
+}
+
+func (dnsServer *DNSServer) Stop() {
+ dnsMutex.Lock()
+ defer dnsMutex.Unlock()
+ if dnsServer.DnsServer == nil {
+ return
+ }
+
+ ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+ defer cancel()
+
+ err := dnsServer.DnsServer.ShutdownContext(ctx)
+ if err != nil {
+ slog.Error("could not shutdown DNS server", "error", err.Error())
+ }
+}

dns/resolver.go

@@ -0,0 +1,89 @@
+package dns
+
+import (
+ "net"
+ "strings"
+ "sync"
+
+ "github.com/miekg/dns"
+ "golang.org/x/exp/slog"
+)
+
+var dnsMapMutex = sync.Mutex{} // used to mutex functions of the DNS
+
+type DNSResolver struct {
+ //dnsEntriesCacheMap map[string]DNSRecord
+ DnsEntriesCacheStore map[string]dns.RR
+}
+
+var DnsResolver *DNSResolver
+
+func init() {
+ DnsResolver = &DNSResolver{}
+}
+
+// GetInstance
+func GetDNSResolverInstance() *DNSResolver {
+ return DnsResolver
+}
+
+// ServeDNS handles a DNS request
+func handleDNSRequest(w dns.ResponseWriter, r *dns.Msg) {
+ slog.Info("receiving DNS query request", "Info", r.Question[0])
+ reply := &dns.Msg{}
+ reply.SetReply(r)
+ reply.RecursionAvailable = true
+ reply.Rcode = dns.RcodeSuccess
+
+ resp := GetDNSResolverInstance().Lookup(r)
+ if resp != nil {
+ reply.Answer = append(reply.Answer, resp)
+ } else {
+ reply.Rcode = dns.RcodeNameError
+ }
+
+ err := w.WriteMsg(reply)
+ if err != nil {
+ slog.Error("write DNS response message error: ", "error", err.Error())
+ }
+}
+
+func (d *DNSResolver) RegisterA(record dnsRecord) error {
+ dnsMapMutex.Lock()
+ defer dnsMapMutex.Unlock()
+
+ r := new(dns.A)
+ r.Hdr = dns.RR_Header{Name: dns.Fqdn(record.Name), Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 3600}
+ r.A = net.ParseIP(record.RData)
+
+ d.DnsEntriesCacheStore[buildDNSEntryKey(record.Name, record.Type)] = r
+
+ slog.Info("registering A record successfully", "Info", d.DnsEntriesCacheStore[buildDNSEntryKey(record.Name, record.Type)])
+
+ return nil
+}
+
+func (d *DNSResolver) RegisterAAAA(record dnsRecord) error {
+ dnsMapMutex.Lock()
+ defer dnsMapMutex.Unlock()
+
+ r := new(dns.AAAA)
+ r.Hdr = dns.RR_Header{Name: record.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 3600}
+ r.AAAA = net.ParseIP(record.RData)
+
+ d.DnsEntriesCacheStore[buildDNSEntryKey(record.Name, record.Type)] = r
+
+ return nil
+}
+
+func (d *DNSResolver) Lookup(m *dns.Msg) dns.RR {
+ dnsMapMutex.Lock()
+ defer dnsMapMutex.Unlock()
+ q := m.Question[0]
+ r, ok := d.DnsEntriesCacheStore[buildDNSEntryKey(strings.TrimSuffix(q.Name, "."), q.Qtype)]
+ if !ok {
+ return nil
+ }
+
+ return r
+}

functions/daemon.go

@@ -16,6 +16,7 @@ import (
  "github.com/gravitl/netclient/cache"
  "github.com/gravitl/netclient/config"
  "github.com/gravitl/netclient/daemon"
+ "github.com/gravitl/netclient/dns"
  "github.com/gravitl/netclient/firewall"
  "github.com/gravitl/netclient/local"
  "github.com/gravitl/netclient/ncutils"
@@ -71,11 +72,12 @@ func Daemon() {
  logger.Log(0, "failed to intialize firewall: ", err.Error())
  }
  cancel := startGoRoutines(&wg)
-
+ dns.GetDNSServerInstance().Start()
  for {
  select {
  case <-quit:
  slog.Info("shutting down netclient daemon")
+ dns.GetDNSServerInstance().Stop()
  //check if it needs to restore the default gateway
  checkAndRestoreDefaultGateway()
  closeRoutines([]context.CancelFunc{
@@ -319,6 +321,9 @@ func setupMQTT(server *config.Server) error {
  for _, node := range nodes {
  node := node
  setSubscriptions(client, &node)
+ if server.ManageDNS {
+ setDNSSubscriptions(client, &node)
+ }
  }
  setHostSubscription(client, server.Name)
  checkin()
@@ -379,6 +384,9 @@ func setupMQTTSingleton(server *config.Server, publishOnly bool) error {
  for _, node := range nodes {
  node := node
  setSubscriptions(client, &node)
+ if server.ManageDNS {
+ setDNSSubscriptions(client, &node)
+ }
  }
  setHostSubscription(client, server.Name)
  }
@@ -434,6 +442,20 @@ func setSubscriptions(client mqtt.Client, node *config.Node) {
  slog.Info("subscribed to updates for node", "node", node.ID, "network", node.Network)
 }
 
+// setDNSSubscriptions sets MQ client subscriptions for a specific node config
+// should be called for each node belonging to a given server
+func setDNSSubscriptions(client mqtt.Client, node *config.Node) {
+ if token := client.Subscribe(fmt.Sprintf("host/dns/sync/%s", node.Network), 0, mqtt.MessageHandler(DNSSync)); token.WaitTimeout(MQ_TIMEOUT*time.Second) && token.Error() != nil {
+ if token.Error() == nil {
+ slog.Error("unable to subscribe to DNS sync for node ", "node", node.ID, "error", "connection timeout")
+ } else {
+ slog.Error("unable to subscribe to DNS sync for node ", "node", node.ID, "error", token.Error())
+ }
+ return
+ }
+ slog.Info("subscribed to DNS sync for node", "node", node.ID, "network", node.Network)
+}
+
 // should only ever use node client configs
 func decryptMsg(serverName string, msg []byte) ([]byte, error) {
  if len(msg) <= 24 { // make sure message is of appropriate length

functions/mqhandlers.go

@@ -16,6 +16,7 @@ import (
  "github.com/gravitl/netclient/cache"
  "github.com/gravitl/netclient/config"
  "github.com/gravitl/netclient/daemon"
+ "github.com/gravitl/netclient/dns"
  "github.com/gravitl/netclient/firewall"
  "github.com/gravitl/netclient/ncutils"
  "github.com/gravitl/netclient/networking"
@@ -108,6 +109,24 @@ func NodeUpdate(client mqtt.Client, msg mqtt.Message) {
  }
 }
 
+// DNSSync -- mqtt message handler for host/dns/sync/<network id> topic
+func DNSSync(client mqtt.Client, msg mqtt.Message) {
+
+ var dnsEntries []models.DNSEntry
+ err := json.Unmarshal([]byte(msg.Payload()), &dnsEntries)
+ if err != nil {
+ slog.Error("error unmarshalling DNS data", "error", err)
+ return
+ }
+
+ if len(dnsEntries) > 0 {
+ err = dns.SyncDNS(dnsEntries)
+ if err != nil {
+ slog.Error("synchronize DNS error ", "error", err.Error())
+ }
+ }
+}
+
 // HostPeerUpdate - mq handler for host peer update peers/host/<HOSTID>/<SERVERNAME>
 func HostPeerUpdate(client mqtt.Client, msg mqtt.Message) {
  var peerUpdate models.HostPeerUpdate

go.mod

@@ -14,13 +14,14 @@ require (
  github.com/google/nftables v0.1.0
  github.com/google/uuid v1.6.0
  github.com/gorilla/websocket v1.5.3
- github.com/gravitl/netmaker v0.24.3-0.20240704124720-780da3b69617
+ github.com/gravitl/netmaker v0.25.1-0.20240913151227-6d03431e469b
  github.com/gravitl/tcping v0.1.2-0.20230801110928-546055ebde06
  github.com/gravitl/txeh v0.0.0-20230509181318-3778c58bd69f
  github.com/guumaster/hostctl v1.1.4
  github.com/hashicorp/go-version v1.7.0
  github.com/kr/pretty v0.3.1
  github.com/matryer/is v1.4.1
+ github.com/miekg/dns v1.1.62
  github.com/minio/selfupdate v0.6.0
  github.com/sasha-s/go-deadlock v0.3.5
  github.com/spf13/cobra v1.8.1
@@ -37,6 +38,7 @@ require (
  golang.zx2c4.com/wireguard/windows v0.5.3
  gopkg.in/yaml.v3 v3.0.1
  gortc.io/stun v1.23.0
+
 )
 
 require (
@@ -74,26 +76,27 @@ require (
  github.com/petermattis/goid v0.0.0-20240813172612-4fcff4a6cae7 // indirect
  github.com/pkg/errors v0.9.1 // indirect
  github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
- github.com/posthog/posthog-go v0.0.0-20211028072449-93c17c49e2b0 // indirect
+ github.com/posthog/posthog-go v1.2.21 // indirect
  github.com/rivo/uniseg v0.4.6 // indirect
  github.com/rogpeppe/go-internal v1.9.0 // indirect
  github.com/rqlite/gorqlite v0.0.0-20240122221808-a8a425b1a6aa // indirect
  github.com/sagikazarmark/locafero v0.4.0 // indirect
  github.com/sagikazarmark/slog-shim v0.1.0 // indirect
+ github.com/seancfoley/bintree v1.3.1 // indirect
+ github.com/seancfoley/ipaddress-go v1.7.0 // indirect
  github.com/sourcegraph/conc v0.3.0 // indirect
  github.com/spf13/afero v1.11.0 // indirect
  github.com/spf13/cast v1.6.0 // indirect
  github.com/spf13/pflag v1.0.5 // indirect
  github.com/subosito/gotenv v1.6.0 // indirect
  github.com/txn2/txeh v1.5.5 // indirect
  github.com/vishvananda/netns v0.0.4 // indirect
- github.com/xtgo/uuid v0.0.0-20140804021211-a0b114877d4c // indirect
  go.uber.org/atomic v1.9.0 // indirect
  go.uber.org/multierr v1.9.0 // indirect
- golang.org/x/mod v0.17.0 // indirect
+ golang.org/x/mod v0.18.0 // indirect
  golang.org/x/sync v0.8.0 // indirect
  golang.org/x/text v0.18.0 // indirect
- golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
+ golang.org/x/tools v0.22.0 // indirect
  golang.zx2c4.com/wintun v0.0.0-20211104114900-415007cec224 // indirect
  gopkg.in/ini.v1 v1.67.0 // indirect
  gopkg.in/yaml.v2 v2.4.0 // indirect