Re-Add DHCP discover fallback for ISPs that don't advertise DHCP

Final fix
Add the domain as it is needed (multiple domains on a home net is niche) Only replace the record if a local one was found Use proper slice updating
2021-05-23 19:38:38 -07:00 · 2021-05-23 19:34:59 -07:00 · 2021-05-23 18:54:09 -07:00 · 2021-05-23 18:31:30 -07:00 · 2021-05-23 17:49:15 -07:00 · 2021-03-15 23:50:19 -07:00
14 changed files with 450 additions and 96 deletions
--- a/8
+++ b/8
@ -20,7 +20,7 @@ ifndef DIR
 	@echo variable DIR unset
 	false
 endif
-	go install github.com/gokrazy/tools/cmd/gokr-packer
+	go install github.com/gokrazy/tools/cmd/gokr-packer@latest
 	GOARCH=amd64 gokr-packer \
 		-gokrazy_pkgs=github.com/gokrazy/gokrazy/cmd/ntp,github.com/gokrazy/gokrazy/cmd/randomd \
 		-kernel_package=github.com/rtr7/kernel \
@ -35,8 +35,8 @@ endif

 recover: #test
 	go install \
-		github.com/gokrazy/tools/cmd/gokr-packer \
-		github.com/rtr7/tools/cmd/rtr7-recover
+		github.com/gokrazy/tools/cmd/gokr-packer@lastet \
+		github.com/rtr7/tools/cmd/rtr7-recover@latest
 	GOARCH=amd64 gokr-packer \
 		-gokrazy_pkgs=github.com/gokrazy/gokrazy/cmd/ntp,github.com/gokrazy/gokrazy/cmd/randomd \
 		-kernel_package=github.com/rtr7/kernel \
@ -70,7 +70,7 @@ strace:
 	(cd /tmp && go test -c router7) && ${SUDO} strace -f -o /tmp/st -s 2048 /tmp/router7.test -test.v #-test.race

 update:
-	rtr7-safe-update -build_command='make -C ~/router7 image DIR=$GOKR_DIR'
+	rtr7-safe-update -build_command='make -C ~/go/src/github.com/rtr7/router7 image DIR=$$GOKR_DIR'

 # sudo ip link add link enp0s31f6 name macvtap0 type macvtap
 # sudo ip link set macvtap0 address 52:55:00:d1:55:03 up
--- a/cmd/dhcp4/dhcp4.go
+++ b/cmd/dhcp4/dhcp4.go
@ -17,11 +17,14 @@
 package main

 import (
+	"context"
 	"encoding/json"
+	"errors"
 	"flag"
 	"fmt"
 	"io/ioutil"
 	"net"
+	"net/http"
 	"os"
 	"os/signal"
 	"path"
@ -48,6 +51,45 @@ var (
 	perm         = flag.String("perm", "/perm", "path to replace /perm")
 )

+func healthy() error {
+	req, err := http.NewRequest("GET", "http://localhost:7733/health.json", nil)
+	if err != nil {
+		return err
+	}
+	ctx, canc := context.WithTimeout(context.Background(), 5*time.Second)
+	defer canc()
+	req = req.WithContext(ctx)
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if got, want := resp.StatusCode, http.StatusOK; got != want {
+		b, _ := ioutil.ReadAll(resp.Body)
+		return fmt.Errorf("%v: got HTTP %v (%s), want HTTP status %v",
+			req.URL.String(),
+			resp.Status,
+			string(b),
+			want)
+	}
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	var reply struct {
+		FirstError string `json:"first_error"`
+	}
+	if err := json.Unmarshal(b, &reply); err != nil {
+		return err
+	}
+
+	if reply.FirstError != "" {
+		return errors.New(reply.FirstError)
+	}
+
+	return nil
+}
+
 func logic() error {
 	leasePath := filepath.Join(*stateDir, "wire/lease.json")
 	if err := os.MkdirAll(filepath.Dir(leasePath), 0755); err != nil {
@ -94,6 +136,7 @@ func logic() error {
 		Min:    10 * time.Second,
 		Max:    1 * time.Minute,
 	}
+ObtainOrRenew:
 	for c.ObtainOrRenew() {
 		if err := c.Err(); err != nil {
 			dur := backoff.Duration()
@ -124,15 +167,42 @@ func logic() error {
 		if err := notify.Process(path.Join(path.Dir(os.Args[0]), "/netconfigd"), syscall.SIGUSR1); err != nil {
 			log.Printf("notifying netconfig: %v", err)
 		}
-		select {
-		case <-time.After(time.Until(c.Config().RenewAfter)):
-			// fallthrough and renew the DHCP lease
-		case <-usr2:
-			log.Printf("SIGUSR2 received, sending DHCPRELEASE")
-			if err := c.Release(); err != nil {
-				return err
+
+		unhealthyCycles := 0
+		for {
+			select {
+			case <-time.After(time.Until(c.Config().RenewAfter)):
+				// fallthrough and renew the DHCP lease
+				continue ObtainOrRenew
+
+			case <-time.After(1 * time.Minute):
+				if err := healthy(); err == nil {
+					unhealthyCycles = 0
+					continue // wait another minute
+				} else {
+					unhealthyCycles++
+					log.Printf("router unhealthy (cycle %d of 5): %v", unhealthyCycles, err)
+					if unhealthyCycles < 5 {
+						continue // wait until unhealthy for longer
+					}
+					// fallthrough
+				}
+				// Still not healthy? Drop DHCP lease and start from scratch.
+				log.Printf("unhealthy for 5 cycles, starting over without lease")
+				c.Ack = nil
+
+			case <-usr2:
+				log.Printf("SIGUSR2 received, sending DHCPRELEASE")
+				if err := c.Release(); err != nil {
+					return err
+				}
+				// Ensure dhcp4 does start from scratch next time
+				// by deleting the DHCPACK file:
+				if err := os.Remove(ackFn); err != nil && !os.IsNotExist(err) {
+					return err
+				}
+				os.Exit(125) // quit supervision by gokrazy
 			}
-			os.Exit(125) // quit supervision by gokrazy
 		}
 	}
 	return c.Err() // permanent error
--- a/cmd/dhcp4d/dhcp4d.go
+++ b/cmd/dhcp4d/dhcp4d.go
@ -239,6 +239,8 @@ type srv struct {
 }

 func newSrv(permDir string) (*srv, error) {
+	mayqtt := MQTT()
+
 	http.Handle("/metrics", promhttp.Handler())
 	if err := updateListeners(); err != nil {
 		return nil, err
@ -304,7 +306,10 @@ func newSrv(permDir string) (*srv, error) {
 			http.Error(w, "missing hostname parameter", http.StatusBadRequest)
 			return
 		}
-		handler.SetHostname(hwaddr, hostname)
+		if err := handler.SetHostname(hwaddr, hostname); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
 		http.Redirect(w, r, "/", http.StatusFound)
 	})

@ -421,6 +426,38 @@ func newSrv(permDir string) (*srv, error) {
 		if err := notify.Process(path.Join(path.Dir(os.Args[0]), "/dnsd"), syscall.SIGUSR1); err != nil {
 			log.Printf("notifying dnsd: %v", err)
 		}
+
+		// Publish the DHCP lease as JSON to MQTT, if configured:
+		leaseVal := struct {
+			Addr         string    `json:"addr"`
+			HardwareAddr string    `json:"hardware_addr"`
+			Expiration   time.Time `json:"expiration"`
+		}{
+			Addr:         latest.Addr.String(),
+			HardwareAddr: latest.HardwareAddr,
+			Expiration:   latest.Expiry.In(time.UTC),
+		}
+		leaseJSON, err := json.Marshal(leaseVal)
+		if err != nil {
+			log.Fatal(err)
+		}
+		// MQTT requires valid UTF-8 and some brokers don’t cope well with
+		// invalid UTF-8: https://github.com/fhmq/hmq/issues/104
+		identifier := strings.ToValidUTF8(latest.Hostname, "")
+		if identifier == "" {
+			identifier = latest.HardwareAddr
+		}
+		select {
+		case mayqtt <- PublishRequest{
+			Topic:    "router7/dhcp4d/lease/" + identifier,
+			Retained: true,
+			Payload:  leaseJSON,
+		}:
+		default:
+			// Channel not ready? skip publishing this lease (best-effort).
+			// This is an easy way of breaking circular dependencies between
+			// MQTT broker and DHCP server, and avoiding deadlocks.
+		}
 	}
 	conn, err := conn.NewUDP4BoundListener(*iface, ":67")
 	if err != nil {
--- a/cmd/dhcp4d/mayqtt.go
+++ b/cmd/dhcp4d/mayqtt.go
@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+type PublishRequest struct {
+	Topic    string
+	Qos      byte
+	Retained bool
+	Payload  interface{}
+}
+
+func publisherLoop(requests <-chan PublishRequest) error {
+	const configFn = "/perm/dhcp4d/mqtt-broker.txt"
+	b, err := ioutil.ReadFile(configFn)
+	if err != nil {
+		// discard requests:
+		for range requests {
+		}
+		return nil
+	}
+	// e.g. tcp://10.0.0.54:1883, which is a static DHCP lease for the dr.lan
+	// Raspberry Pi, which is running an MQTT broker in my network.
+	broker := strings.TrimSpace(string(b))
+	log.Printf("Connecting to MQTT broker %q (configured in %s)", broker, configFn)
+	opts := mqtt.NewClientOptions().AddBroker(broker)
+	opts.SetClientID("dhcp4d")
+	opts.SetConnectRetry(true)
+	mqttClient := mqtt.NewClient(opts)
+	if token := mqttClient.Connect(); token.Wait() && token.Error() != nil {
+		return fmt.Errorf("MQTT connection failed: %v", token.Error())
+	}
+
+	for r := range requests {
+		// discard Token, MQTT publishing is best-effort
+		_ = mqttClient.Publish(r.Topic, r.Qos, r.Retained, r.Payload)
+	}
+	return nil
+}
+
+func MQTT() chan<- PublishRequest {
+	result := make(chan PublishRequest)
+	go func() {
+		if err := publisherLoop(result); err != nil {
+			log.Print(err)
+		}
+	}()
+	return result
+}
--- a/cmd/diagd/diagd.go
+++ b/cmd/diagd/diagd.go
@ -34,12 +34,12 @@ import (

 	"github.com/rtr7/router7/internal/diag"
 	"github.com/rtr7/router7/internal/multilisten"
+
+	_ "net/http/pprof"
 )

 var httpListeners = multilisten.NewPool()

-var perm = flag.String("perm", "/perm", "path to replace /perm")
-
 func updateListeners() error {
 	hosts, err := gokrazy.PrivateInterfaceAddrs()
 	if err != nil {
@ -81,10 +81,20 @@ func firstError(re *diag.EvalResult) string {
 }

 func logic() error {
+	var (
+		ifname = flag.String("interface",
+			"uplink0",
+			"interface name to query")
+		perm = flag.String("perm",
+			"/perm",
+			"path to replace /perm")
+	)
 	const (
-		uplink        = "uplink0" /* enp0s31f6 */
 		ip6allrouters = "ff02::2" // no /etc/hosts on gokrazy
 	)
+	flag.Parse()
+	uplink := *ifname
+	diag.Perm = *perm
 	m := diag.NewMonitor(diag.Link(uplink).
 		Then(diag.DHCPv4().
 			Then(diag.Ping4Gateway().
@ -135,9 +145,6 @@ func logic() error {
 }

 func main() {
-	flag.Parse()
-	diag.Perm = *perm
-
 	if err := logic(); err != nil {
 		log.Fatal(err)
 	}
--- a/cmd/dnsd/dnsd.go
+++ b/cmd/dnsd/dnsd.go
@ -39,20 +39,21 @@ import (
 )

 var (
-	httpListeners = multilisten.NewPool()
-	dnsListeners  = multilisten.NewPool()
+	httpListeners   = multilisten.NewPool()
+	dnsUDPListeners = multilisten.NewPool()
+	dnsTCPListeners = multilisten.NewPool()

 	perm   = flag.String("perm", "/perm", "path to replace /perm")
 	domain = flag.String("domain", "lan", "domain name for your network")
 )

 func updateListeners(mux *miekgdns.ServeMux) error {
-	hosts, err := gokrazy.PrivateInterfaceAddrs()
+	privateAddrs, err := gokrazy.PrivateInterfaceAddrs()
 	if err != nil {
 		return err
 	}

-	dnsListeners.ListenAndServe(hosts, func(host string) multilisten.Listener {
+	dnsUDPListeners.ListenAndServe(privateAddrs, func(host string) multilisten.Listener {
 		return &listenerAdapter{&miekgdns.Server{
 			Addr:    net.JoinHostPort(host, "53"),
 			Net:     "udp",
@ -60,11 +61,19 @@ func updateListeners(mux *miekgdns.ServeMux) error {
 		}}
 	})

-	if net1, err := multilisten.IPv6Net1(*perm); err == nil {
-		hosts = append(hosts, net1)
+	dnsTCPListeners.ListenAndServe(privateAddrs, func(host string) multilisten.Listener {
+		return &listenerAdapter{&miekgdns.Server{
+			Addr:    net.JoinHostPort(host, "53"),
+			Net:     "tcp",
+			Handler: mux,
+		}}
+	})
+
+	if net1, err := multilisten.IPv6Net1("/perm"); err == nil {
+		privateAddrs = append(privateAddrs, net1)
 	}

-	httpListeners.ListenAndServe(hosts, func(host string) multilisten.Listener {
+	httpListeners.ListenAndServe(privateAddrs, func(host string) multilisten.Listener {
 		return &http.Server{Addr: net.JoinHostPort(host, "8053")}
 	})

--- a/go.mod
+++ b/go.mod
@ -2,39 +2,36 @@ module github.com/rtr7/router7

 go 1.13

-replace github.com/gokrazy/gokrazy => git.narnian.us/lordwelch/gokrazy v0.0.0-20210109232047-4e1975ff77aa
-
 require (
 	github.com/andreyvit/diff v0.0.0-20170406064948-c7f18ee00883
-	github.com/digineo/go-ping v1.0.1
-	github.com/gokrazy/gokrazy v0.0.0-20210108081039-067330db5542
+	github.com/digineo/go-ping v1.0.0
+	github.com/eclipse/paho.mqtt.golang v1.3.1
+	github.com/gokrazy/gokrazy v0.0.0-20201006151115-caded4667633
+	github.com/gokrazy/internal v0.0.0-20201230135541-e2046189e529 // indirect
 	github.com/google/go-cmp v0.5.4
 	github.com/google/gopacket v1.1.19
 	github.com/google/nftables v0.0.0-20201230142148-715e31cb3c31
 	github.com/google/renameio v1.0.0
 	github.com/insomniacslk/dhcp v0.0.0-20201112113307-4de412bc85d8
 	github.com/jpillora/backoff v1.0.0
-	github.com/kr/text v0.2.0 // indirect
 	github.com/krolaw/dhcp4 v0.0.0-20190909130307-a50d88189771
 	github.com/libdns/cloudflare v0.0.0-20200528144945-97886e7873b1
 	github.com/libdns/libdns v0.1.0
 	github.com/mdlayher/ndp v0.0.0-20200602162440-17ab9e3e5567
+	github.com/mdlayher/netlink v1.2.0 // indirect
 	github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065
 	github.com/miekg/dns v1.1.35
-	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/prometheus/client_golang v1.9.0
 	github.com/rtr7/dhcp4 v0.0.0-20181120124042-778e8c2e24a5
 	github.com/sergi/go-diff v1.1.0 // indirect
-	github.com/u-root/u-root v6.0.0+incompatible // indirect
-	github.com/vishvananda/netlink v1.1.0
-	github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f // indirect
+	github.com/vishvananda/netlink v1.1.1-0.20200221165523-c79a4b7b4066
+	github.com/vishvananda/netns v0.0.0-20201230012202-c4f3ca719c73 // indirect
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
 	golang.org/x/net v0.0.0-20201224014010-6772e930b67b
-	golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208
-	golang.org/x/sys v0.0.0-20210108172913-0df2131ae363
+	golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
+	golang.org/x/sys v0.0.0-20201223074533-0d417f636930
 	golang.org/x/time v0.0.0-20201208040808-7e3f01d25324
 	golang.zx2c4.com/wireguard v0.0.20201118 // indirect
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20200609130330-bd2cb7843e1b
 	google.golang.org/protobuf v1.25.0 // indirect
-	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 )
--- a/go.sum
+++ b/go.sum
@ -1,7 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-git.narnian.us/lordwelch/gokrazy v0.0.0-20210109232047-4e1975ff77aa h1:zJZ5VKVhe6LYdxTy3U7JPpXvFCdxumY40OV07OsTjHk=
-git.narnian.us/lordwelch/gokrazy v0.0.0-20210109232047-4e1975ff77aa/go.mod h1:tUrCiUyBdSLkNIS3w7KZA1nz7lNIS0irf1pBX6J6E44=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
@ -24,6 +22,7 @@ github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a/go.mod h1:DAHtR1m6l
 github.com/aws/aws-lambda-go v1.13.3/go.mod h1:4UKl9IzQMoD+QF79YdCuzCwp8VbmG4VAQwij/eHl5CU=
 github.com/aws/aws-sdk-go v1.27.0/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/aws/aws-sdk-go-v2 v0.18.0/go.mod h1:JWVYvqSMppoMJC0x5wdwiImzgXTI9FuZwxzkQq9wy+g=
+github.com/beevik/ntp v0.2.0 h1:sGsd+kAXzT0bfVfzJfce04g+dSRfrs+tbQW8lweuYgw=
 github.com/beevik/ntp v0.2.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
@ -43,32 +42,33 @@ github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3Ee
 github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/creack/pty v1.1.7 h1:6pwm8kMQKCmgUg0ZHTm5+/YvRK0s3THD/28+T6/kk4A=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/digineo/go-logwrap v0.0.0-20181106161722-a178c58ea3f0 h1:OT/LKmj81wMymnWXaKaKBR9n1vPlu+GC0VVKaZP6kzs=
 github.com/digineo/go-logwrap v0.0.0-20181106161722-a178c58ea3f0/go.mod h1:DmqdumeAKGQNU5E8MN0ruT5ZGx8l/WbAsMbXCXcSEts=
-github.com/digineo/go-ping v1.0.1 h1:Yn9hwM0RY4j4D3gcmLvRJf0d7MrbucfUhnOeVDvcVyk=
-github.com/digineo/go-ping v1.0.1/go.mod h1:uCbFC0VUqGNBNiev44BGSxfOrEAmC73GjpRje1l40Zo=
+github.com/digineo/go-ping v1.0.0 h1:gOuD3YzkIcW/0Y2IAe27bsMKtpfNZdoX1Rnc1RGYOSI=
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@ -82,8 +82,11 @@ github.com/gogo/googleapis v1.1.0/go.mod h1:gf4bu3Q80BeJ6H1S1vYPm8/ELATdvryBaNFG
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@ -109,6 +112,7 @@ github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
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@ -127,6 +131,8 @@ github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51
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@ -166,6 +172,8 @@ github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4/go.mod h1:WGu
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@ -180,11 +188,11 @@ github.com/koneu/natend v0.0.0-20150829182554-ec0926ea948d/go.mod h1:QHb4k4cr1fQ
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@ -194,16 +202,13 @@ github.com/libdns/libdns v0.1.0 h1:0ctCOrVJsVzj53mop1angHp/pE3hmAhP7KiHvR0HD04=
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@ -217,6 +222,8 @@ github.com/mdlayher/netlink v1.0.0/go.mod h1:KxeJAFOFLG6AjpyDkQ/iIhxygIUKD+vcwqc
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@ -248,8 +255,6 @@ github.com/nats-io/nats.go v1.9.1/go.mod h1:ZjDU1L/7fJ09jvUSRVBR2e7+RnLiiIQyqyzE
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@ -306,8 +311,7 @@ github.com/prometheus/procfs v0.1.3/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4O
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@ -345,12 +349,12 @@ github.com/u-root/u-root v7.0.0+incompatible h1:u+KSS04pSxJGI5E7WE4Bs9+Zd75QjFv+
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 github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
 github.com/urfave/cli v1.22.1/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
-github.com/vishvananda/netlink v1.1.0 h1:1iyaYNBLmP6L0220aDnYQpo1QEV4t4hJ+xEEhhJH8j0=
-github.com/vishvananda/netlink v1.1.0/go.mod h1:cTgwzPIzzgDAYoQrMm0EdrjRUBkTqKYppBueQtXaqoE=
+github.com/vishvananda/netlink v1.1.1-0.20200221165523-c79a4b7b4066 h1:IlMBmSoCDZ9UY3OehFgvKSIgMNnU1vbAD4Fl+y2Rbis=
+github.com/vishvananda/netlink v1.1.1-0.20200221165523-c79a4b7b4066/go.mod h1:FSQhuTO7eHT34mPzX+B04SUAjiqLxtXs1et0S6l9k4k=
 github.com/vishvananda/netns v0.0.0-20180720170159-13995c7128cc/go.mod h1:ZjcWmFBXmLKZu9Nxj3WKYEafiSqer2rnvPr0en9UNpI=
 github.com/vishvananda/netns v0.0.0-20191106174202-0a2b9b5464df/go.mod h1:JP3t17pCcGlemwknint6hfoeCVQrEMVwxRLRjXpq+BU=
-github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f h1:p4VB7kIXpOQvVn1ZaTIVp+3vuYAXFe3OJEvjbUYJLaA=
-github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f/go.mod h1:DD4vA1DwXk04H54A1oHXtwZmA0grkVMdPxx/VGLCah0=
+github.com/vishvananda/netns v0.0.0-20201230012202-c4f3ca719c73 h1:JGMFiSX7pNu3l0DRO8sjxgA7ybQNE+HeuKIG23PjsN4=
+github.com/vishvananda/netns v0.0.0-20201230012202-c4f3ca719c73/go.mod h1:DD4vA1DwXk04H54A1oHXtwZmA0grkVMdPxx/VGLCah0=
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 gitlab.com/golang-commonmark/puny v0.0.0-20191124015043-9f83538fa04f h1:Wku8eEdeJqIOFHtrfkYUByc4bCaTeA6fL0UJgfEiFMI=
 gitlab.com/golang-commonmark/puny v0.0.0-20191124015043-9f83538fa04f/go.mod h1:Tiuhl+njh/JIg0uS/sOJVYi0x2HEa5rc1OAaVsb5tAs=
@ -410,11 +414,13 @@ golang.org/x/net v0.0.0-20191003171128-d98b1b443823/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20191007182048-72f939374954/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20191028085509-fe3aa8a45271/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200202094626-16171245cfb2/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200425230154-ff2c4b7c35a0/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200602114024-627f9648deb9/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20201010224723-4f7140c49acb/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.0.0-20201209123823-ac852fbbde11/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20201216054612-986b41b23924 h1:QsnDpLLOKwHBBDa8nDws4DYNc/ryVW2vCpxCs09d4PY=
+golang.org/x/net v0.0.0-20201216054612-986b41b23924/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20201224014010-6772e930b67b h1:iFwSg7t5GZmB/Q5TjiEAsdoLDrdJRC1RiF2WhuV29Qw=
 golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@ -425,9 +431,10 @@ golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a h1:WXEvlFVvvGxCJLG6REjsT03iWnKLEWinaScsxF2Vm2o=
 golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208 h1:qwRHBd0NqMbJxfbotnDhm2ByMI1Shq4Y6oRJo21SGJA=
-golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a h1:DcqTD9SDLc+1P/r1EmRBwnVsrOwW+kk2vWf9n+1sGhs=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@ -436,6 +443,7 @@ golang.org/x/sys v0.0.0-20181026203630-95b1ffbd15a5/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20181107165924-66b7b1311ac8/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20181228144115-9a3f9b0469bb/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190411185658-b44545bcd369/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@ -444,8 +452,6 @@ golang.org/x/sys v0.0.0-20190418153312-f0ce4c0180be/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190606122018-79a91cf218c4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190606203320-7fc4e5ec1444/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190826190057-c7b8b68b1456/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@ -455,10 +461,9 @@ golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191029155521-f43be2a4598c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191220142924-d4481acd189f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200121082415-34d275377bf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200217220822-9197077df867/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200406155108-e3b113bbe6a4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200602100848-8d3cce7afc34/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@ -467,19 +472,22 @@ golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201005065044-765f4ea38db3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201017003518-b09fb700fbb7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201101102859-da207088b7d1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201112073958-5cba982894dd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201117222635-ba5294a509c7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201118182958-a01c418693c7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201214210602-f9fddec55a1e h1:AyodaIpKjppX+cBfTASF2E1US3H2JFBj920Ot3rtDjs=
 golang.org/x/sys v0.0.0-20201214210602-f9fddec55a1e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210108172913-0df2131ae363 h1:wHn06sgWHMO1VsQ8F+KzDJx/JzqfsNLnc+oEi07qD7s=
-golang.org/x/sys v0.0.0-20210108172913-0df2131ae363/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201218084310-7d0127a74742/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201223074533-0d417f636930 h1:vRgIt+nup/B/BwIS0g2oC0haq0iqbV3ZA+u6+0TlNCo=
+golang.org/x/sys v0.0.0-20201223074533-0d417f636930/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@ -539,12 +547,12 @@ google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.25.0 h1:Ejskq+SyPohKW+1uil0JJMtmHCgJPJ/qWTxr8qp+R4c=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
+gopkg.in/DATA-DOG/go-sqlmock.v1 v1.3.0/go.mod h1:OdE7CF6DbADk7lN8LIKRzRJTTZXIjtWgA5THM5lhBAw=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/cheggaaa/pb.v1 v1.0.25/go.mod h1:V/YB90LKu/1FcN3WVnfiiE5oMCibMjukxqG/qStrOgw=
 gopkg.in/cheggaaa/pb.v1 v1.0.27/go.mod h1:V/YB90LKu/1FcN3WVnfiiE5oMCibMjukxqG/qStrOgw=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
--- a/integration/netconfig/netconfig_test.go
+++ b/integration/netconfig/netconfig_test.go
@ -471,3 +471,124 @@ func ipLines(args ...string) ([]string, error) {

 	return strings.Split(strings.TrimSpace(outstr), "\n"), nil
 }
+
+func TestDHCPv4OldAddressDeconfigured(t *testing.T) {
+	if os.Getenv("HELPER_PROCESS") == "1" {
+		tmp, err := ioutil.TempDir("", "router7")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer os.RemoveAll(tmp)
+
+		for _, golden := range []struct {
+			filename, content string
+		}{
+			{"dhcp4/wire/lease.json", goldenDhcp4},
+			{"interfaces.json", goldenInterfaces},
+		} {
+			if err := os.MkdirAll(filepath.Join(tmp, filepath.Dir(golden.filename)), 0755); err != nil {
+				t.Fatal(err)
+			}
+			if err := ioutil.WriteFile(filepath.Join(tmp, golden.filename), []byte(golden.content), 0600); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		if err := os.MkdirAll(filepath.Join(tmp, "root", "etc"), 0755); err != nil {
+			t.Fatal(err)
+		}
+
+		if err := os.MkdirAll(filepath.Join(tmp, "root", "tmp"), 0755); err != nil {
+			t.Fatal(err)
+		}
+
+		if err := netconfig.Apply(tmp, filepath.Join(tmp, "root")); err != nil {
+			t.Fatalf("netconfig.Apply: %v", err)
+		}
+
+		const anotherDhcp4 = `
+{
+  "valid_until":"2018-05-18T23:46:04.429895261+02:00",
+  "client_ip":"85.195.199.99",
+  "subnet_mask":"255.255.255.128",
+  "router":"85.195.199.1",
+  "dns":[
+    "77.109.128.2",
+    "213.144.129.20"
+  ]
+}
+`
+		if err := ioutil.WriteFile(filepath.Join(tmp, "dhcp4/wire/lease.json"), []byte(anotherDhcp4), 0600); err != nil {
+			t.Fatal(err)
+		}
+
+		if err := netconfig.Apply(tmp, filepath.Join(tmp, "root")); err != nil {
+			t.Fatalf("netconfig.Apply: %v", err)
+		}
+
+		return
+	}
+	const ns = "ns5" // name of the network namespace to use for this test
+
+	add := exec.Command("ip", "netns", "add", ns)
+	add.Stderr = os.Stderr
+	if err := add.Run(); err != nil {
+		t.Fatalf("%v: %v", add.Args, err)
+	}
+	defer exec.Command("ip", "netns", "delete", ns).Run()
+
+	nsSetup := []*exec.Cmd{
+		exec.Command("ip", "-netns", ns, "link", "add", "dummy0", "type", "dummy"),
+		exec.Command("ip", "-netns", ns, "link", "add", "lan0", "type", "dummy"),
+		exec.Command("ip", "-netns", ns, "link", "set", "dummy0", "address", "02:73:53:00:ca:fe"),
+		exec.Command("ip", "-netns", ns, "link", "set", "lan0", "address", "02:73:53:00:b0:0c"),
+	}
+
+	for _, cmd := range nsSetup {
+		if err := cmd.Run(); err != nil {
+			t.Fatalf("%v: %v", cmd.Args, err)
+		}
+	}
+
+	cmd := exec.Command("ip", "netns", "exec", ns, os.Args[0], "-test.run=^TestDHCPv4OldAddressDeconfigured$")
+	cmd.Env = append(os.Environ(), "HELPER_PROCESS=1")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Run("VerifyAddresses", func(t *testing.T) {
+		show := exec.Command("ip", "-netns", ns, "address", "show", "dev", "uplink0")
+		show.Stderr = os.Stderr
+		addrs, err := show.Output()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		oldAddrRe := regexp.MustCompile(`(?m)^\s*inet 85.195.207.62/25 brd 85.195.207.127 scope global uplink0$`)
+		if oldAddrRe.MatchString(string(addrs)) {
+			t.Fatalf("regexp %s unexpectedly still matches %s", oldAddrRe, string(addrs))
+		}
+
+		addrRe := regexp.MustCompile(`(?m)^\s*inet 85.195.199.99/25 brd 85.195.199.127 scope global uplink0$`)
+		if !addrRe.MatchString(string(addrs)) {
+			t.Fatalf("regexp %s does not match %s", addrRe, string(addrs))
+		}
+
+		wantRoutes := []string{
+			"default via 85.195.199.1 proto dhcp src 85.195.199.99 ",
+			"85.195.199.0/25 proto kernel scope link src 85.195.199.99 ",
+			"85.195.199.1 proto dhcp scope link src 85.195.199.99",
+		}
+
+		routes, err := ipLines("-netns", ns, "route", "show", "dev", "uplink0")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if diff := cmp.Diff(wantRoutes, routes); diff != "" {
+			t.Fatalf("routes: diff (-want +got):\n%s", diff)
+		}
+	})
+}
--- a/internal/dhcp4/dhcp4.go
+++ b/internal/dhcp4/dhcp4.go
@ -44,6 +44,7 @@ type Client struct {

 	err          error
 	once         sync.Once
+	onceErr      error
 	connection   net.PacketConn
 	hardwareAddr net.HardwareAddr
 	hostname     string
@ -86,7 +87,6 @@ var errNAK = errors.New("received DHCPNAK")

 // ObtainOrRenew returns false when encountering a permanent error.
 func (c *Client) ObtainOrRenew() bool {
-	var onceErr error
 	c.once.Do(func() {
 		if c.timeNow == nil {
 			c.timeNow = time.Now
@ -96,13 +96,13 @@ func (c *Client) ObtainOrRenew() bool {
 				LinuxSockDGRAM: true,
 			})
 			if err != nil {
-				onceErr = err
+				c.onceErr = err
 				return
 			}
 			c.connection = conn
 		}
 		if c.connection == nil && c.Interface == nil {
-			onceErr = fmt.Errorf("c.Interface is nil")
+			c.onceErr = fmt.Errorf("c.Interface is nil")
 			return
 		}
 		if c.hardwareAddr == nil && c.HWAddr != nil {
@ -117,14 +117,14 @@ func (c *Client) ObtainOrRenew() bool {
 		if c.hostname == "" {
 			var utsname unix.Utsname
 			if err := unix.Uname(&utsname); err != nil {
-				onceErr = err
+				c.onceErr = err
 				return
 			}
 			c.hostname = string(utsname.Nodename[:bytes.IndexByte(utsname.Nodename[:], 0)])
 		}
 	})
-	if onceErr != nil {
-		c.err = onceErr
+	if c.onceErr != nil {
+		c.err = c.onceErr
 		return false // permanent error
 	}
 	c.err = nil // clear previous error
@ -141,7 +141,7 @@ func (c *Client) ObtainOrRenew() bool {
 			c.timeoutCount++
 			if c.timeoutCount > 3 {
 				c.timeoutCount = 0
-				c.Ack = nil // start over at DHCPDISCOVER
+				c.Ack = nil // start over at DHCPDISCOVER it has failed 3 times
 			}
 			return true // temporary error
 		}
@ -167,6 +167,7 @@ func (c *Client) ObtainOrRenew() bool {
 		}
 	}
 	c.cfg.RenewAfter = c.timeNow().Add(lease.RenewalTime)
+	c.timeoutCount = 0
 	return true
 }

--- a/internal/dhcp4d/dhcp4d.go
+++ b/internal/dhcp4d/dhcp4d.go
@ -104,13 +104,17 @@ func NewHandler(dir string, iface *net.Interface, ifaceName string, conn net.Pac
 	copy(start, serverIP)
 	start[len(start)-1]++
 	return &Handler{
-		rawConn:     conn,
-		iface:       iface,
-		leasesHW:    make(map[string]int),
-		leasesIP:    make(map[int]*Lease),
-		serverIP:    serverIP,
-		start:       start,
-		leaseRange:  230,
+		rawConn:    conn,
+		iface:      iface,
+		leasesHW:   make(map[string]int),
+		leasesIP:   make(map[int]*Lease),
+		serverIP:   serverIP,
+		start:      start,
+		leaseRange: 230,
+		// Apple recommends a DHCP lease time of 1 hour in
+		// https://support.apple.com/de-ch/HT202068,
+		// so if 20 minutes ever causes any trouble,
+		// we should try increasing it to 1 hour.
 		LeasePeriod: 20 * time.Minute,
 		options:     options,
 		timeNow:     time.Now,
@ -142,14 +146,18 @@ func (h *Handler) callLeasesLocked(lease *Lease) {
 	h.Leases(leases, lease)
 }

-func (h *Handler) SetHostname(hwaddr, hostname string) {
+func (h *Handler) SetHostname(hwaddr, hostname string) error {
 	h.leasesMu.Lock()
 	defer h.leasesMu.Unlock()
 	leaseNum := h.leasesHW[hwaddr]
 	lease := h.leasesIP[leaseNum]
+	if lease.HardwareAddr != hwaddr || lease.Expired(h.timeNow()) {
+		return fmt.Errorf("hwaddr %v does not have a valid lease", hwaddr)
+	}
 	lease.Hostname = hostname
 	lease.HostnameOverride = hostname
 	h.callLeasesLocked(lease)
+	return nil
 }

 func (h *Handler) findLease() int {
--- a/internal/diag/ping.go
+++ b/internal/diag/ping.go
@ -73,6 +73,7 @@ func (d *ping4gw) Evaluate() (string, error) {
 	if err != nil {
 		return "", err
 	}
+	defer p.Close()
 	rtt, err := p.Ping(addr, timeout)
 	if err != nil {
 		return "", err
@ -115,6 +116,7 @@ func (d *ping4) Evaluate() (string, error) {
 	if err != nil {
 		return "", err
 	}
+	defer p.Close()
 	rtt, err := p.Ping(addr, timeout)
 	if err != nil {
 		return "", err
@ -177,6 +179,7 @@ func (d *ping6gw) Evaluate() (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("ping.New(::): %v", err)
 	}
+	defer p.Close()
 	rtt, err := p.Ping(addr, timeout)
 	if err != nil {
 		return "", fmt.Errorf("ping6(%v, %v): %v", addr, timeout, err)
@ -251,6 +254,7 @@ func (d *ping6) Evaluate() (string, error) {
 	if err != nil {
 		return "", err
 	}
+	defer p.Close()
 	ctx, canc := context.WithTimeout(context.Background(), timeout)
 	defer canc()
 	if strings.HasPrefix(addr.String(), "ff02::") {
@ -274,6 +278,11 @@ func (d *ping6) Evaluate() (string, error) {
 			if localAddr[reply.Address.String()] {
 				continue
 			}
+			go func() {
+				for range replies {
+					// drain channel
+				}
+			}()
 			return formatRTT(reply.Duration) + " from " + reply.Address.String(), nil
 		}
 		return "", fmt.Errorf("no responses to %s within %v", addr, timeout)
--- a/internal/dns/dns.go
+++ b/internal/dns/dns.go
@ -227,10 +227,10 @@ func (s *Server) hostByIP(n string) (string, bool) {
 	return r, ok
 }

-func (s *Server) subname(hostname, host string) (IP, bool) {
+func (s *Server) subname(domain, host string) (IP, bool) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	r, ok := s.subnames[lcHostname(strings.ToLower(hostname))][lcHostname(strings.ToLower(host))]
+	r, ok := s.subnames[lcHostname(strings.ToLower(domain))][lcHostname(strings.ToLower(host))]
 	return r, ok
 }

@ -544,11 +544,26 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
 			}
 			continue // fall back to next-slower upstream
 		}
+		if len(in.Answer) > 1 {
+			if in.Answer[0].Header().Rrtype == dns.TypeCNAME {
+				for i, rr := range in.Answer {
+					if rr != nil && rr.Header() != nil && rr.Header().Rrtype == dns.TypeA {
+						newRR, err := s.resolveSubname(string(s.domain), dns.Question{strings.ToLower(rr.Header().Name), dns.TypeA, dns.ClassINET})
+						if err == nil && newRR != nil {
+							in.Answer[i] = newRR
+						}
+					}
+				}
+			}
+		}
 		w.WriteMsg(in)
 		if idx > 0 {
 			// re-order this upstream to the front of s.upstream.
 			s.upstreamMu.Lock()
-			s.upstream = append(append([]string{u}, s.upstream[:idx]...), s.upstream[idx+1:]...)
+			// if the upstreams were reordered in the meantime leave them alone
+			if s.upstream[idx] == u {
+				s.upstream = append(append([]string{u}, s.upstream[:idx]...), s.upstream[idx+1:]...)
+			}
 			s.upstreamMu.Unlock()
 		}
 		return
@ -584,13 +599,13 @@ func (s *Server) promInc(label string, r *dns.Msg) {
 	s.prom.upstream.WithLabelValues(label).Inc()
 }

-func (s *Server) subnameHandler(hostname lcHostname) func(w dns.ResponseWriter, r *dns.Msg) {
+func (s *Server) subnameHandler(domain lcHostname) func(w dns.ResponseWriter, r *dns.Msg) {
 	return func(w dns.ResponseWriter, r *dns.Msg) {
 		if len(r.Question) != 1 { // TODO: answer all questions we can answer
 			s.promInc("local", r)
 			return
 		}
-		rr, err := s.resolveSubname(string(hostname), r.Question[0])
+		rr, err := s.resolveSubname(string(domain), r.Question[0])

 		if err != nil {
 			s.promInc("local", r)
--- a/internal/netconfig/netconfig.go
+++ b/internal/netconfig/netconfig.go
@ -75,7 +75,8 @@ func applyDhcp4(dir string) error {
 		return err
 	}

-	link, err := netlink.LinkByName("uplink0")
+	const linkName = "uplink0"
+	link, err := netlink.LinkByName(linkName)
 	if err != nil {
 		return err
 	}
@ -89,7 +90,8 @@ func applyDhcp4(dir string) error {
 		return err
 	}

-	addr, err := netlink.ParseAddr(fmt.Sprintf("%s/%d", got.ClientIP, subnetSize))
+	gotAddr := fmt.Sprintf("%s/%d", got.ClientIP, subnetSize)
+	addr, err := netlink.ParseAddr(gotAddr)
 	if err != nil {
 		return err
 	}
@ -99,8 +101,24 @@ func applyDhcp4(dir string) error {
 		return fmt.Errorf("netlink.NewHandle: %v", err)
 	}
 	defer h.Delete()
+	log.Printf("replacing address %v on %v", addr, linkName)
 	if err := h.AddrReplace(link, addr); err != nil {
-		return fmt.Errorf("AddrReplace(%v): %v", addr, err)
+		return fmt.Errorf("AddrReplace(%v, %v): %v", linkName, addr, err)
+	}
+
+	addrs, err := h.AddrList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return fmt.Errorf("AddrList(%v): %v", linkName, err)
+	}
+	for _, addr := range addrs {
+		ipnet := addr.IPNet.String() // e.g. "85.195.199.99/25"
+		if ipnet == gotAddr {
+			continue
+		}
+		log.Printf("de-configuring old IP address %s from %v", ipnet, linkName)
+		if err := h.AddrDel(link, &addr); err != nil {
+			return fmt.Errorf("AddrDel(%v, %v): %v", linkName, addr, err)
+		}
 	}

 	// from include/uapi/linux/rtnetlink.h
Author	SHA1	Message	Date
lordwelch	b801bf699f	Re-Add DHCP discover fallback for ISPs that don't advertise DHCP	2021-05-23 19:38:38 -07:00
lordwelch	e34b880a55	Final fix Add the domain as it is needed (multiple domains on a home net is niche) Only replace the record if a local one was found Use proper slice updating	2021-05-23 19:34:59 -07:00
lordwelch	ac0ef71d9f	Fix null check	2021-05-23 18:54:09 -07:00
lordwelch	9533787aac	Fix err check go mod tidy	2021-05-23 18:31:30 -07:00
lordwelch	29eaa11052	Update parameters for clarity Hijack the final A record in a CNAME chain if it is in our records	2021-05-23 17:49:15 -07:00
lordwelch	9ee285e139	fix build	2021-03-15 23:50:19 -07:00
lordwelch	ef50f7c2e4	Merge remote-tracking branch 'origin/master'	2021-03-15 22:44:39 -07:00
lordwelch	a592bbc76a	Revert "Fallback to DHCPDISCOVER after 4 failed timeouts" This reverts commit `68105841c6`.	2021-03-15 22:34:17 -07:00
Michael Stapelberg	3834acfa2b	dhcp4d: ensure MQTT topic names are valid UTF-8 https://twitter.com/zekjur/status/1347295676909158400	2021-01-07 22:52:58 +01:00
Michael Stapelberg	c30bf38438	bump dependencies	2020-12-31 22:13:25 +01:00
Michael Stapelberg	5f25043b94	dhcp4d: only publish to MQTT when channel is ready to prevent deadlocks	2020-12-31 16:42:12 +01:00
Michael Stapelberg	c3c531931c	retry MQTT connections, even if initial connection attempt fails	2020-12-31 16:42:01 +01:00
Michael Stapelberg	32b0dc7d59	Makefile: Go 1.16’s go install wants the @latest suffix	2020-12-19 13:52:03 +01:00
Michael Stapelberg	04f2be01d9	dhcp4d: optionally publish DHCP leases to MQTT Enable using: mkdir -p /perm/dhcp4d echo 'tcp://10.0.0.54:1883' > /perm/dhcp4d/mqtt-broker.txt	2020-12-19 13:34:46 +01:00
Michael Stapelberg	e5ea79aef8	update go.{mod,sum} with Go 1.16beta1	2020-12-18 10:10:17 +01:00
Robert Obryk	f8d1b4c8f2	internal/dhcp4: make persistent errors actally persistent (#62 ) Previously, a permanent error would not be persisted for future invocations of ObtainOrRenew. In practice, the daemon immediately exited, so this made no difference.	2020-11-23 09:35:00 +01:00
Robert Obryk	8de4eb7ba1	internal/dns: prevent upstreams from being lost during reordering (#63 ) If upstreams were reordered between start of an upstream request and its conclusion, the move-to-front operation would likely incorrectly reorder upstreams: duplicate one and remove another. Instead, we abandon the move-to-front operation if that was about to happen.	2020-11-23 09:34:04 +01:00
Robert Obryk	0507d93b3d	dhcp4d: ensure that SetHostname operates on the correct lease (#64 ) Previously SetHostname could operate on an expired lease, or even on a lease for a different hwaddr, if the lease for the correct hwaddr expired and the same lease ID was given away to someone else. That's though mostly a theoretical concern, given the actual usage of SetHostname and the time scales involved.	2020-11-23 09:32:42 +01:00
Michael Stapelberg	7f135438b8	dhcp4d: mention apple-suggested lease time of 1 hour	2020-11-01 19:24:24 +01:00
Michael Stapelberg	a8fce3cbbc	diag: drain ping reply channel to avoid goroutine leak	2020-09-14 22:10:09 +02:00
Michael Stapelberg	99c4046ebf	diagd: import net/http/pprof	2020-09-14 22:10:07 +02:00
Michael Stapelberg	efbe826a4e	diagd: -interface flag for easier testing	2020-09-14 22:10:07 +02:00
Michael Stapelberg	416c1a58f6	diag: plug socket leak by adding missing Close()	2020-09-14 22:10:07 +02:00
Michael Stapelberg	f8d79d0ecc	dhcp4: close healthiness checking connection	2020-09-14 12:54:14 +02:00
Michael Stapelberg	fddfe80222	dhcp4: start from scratch after 5 minutes of continued unhealthiness fixes #58	2020-09-14 09:06:05 +02:00
Michael Stapelberg	876f8e320f	netconfig: de-configure old DHCPv4 addresses from uplink0 It is generally not a good idea to have multiple IP addresses on the same interface unless managing their relative priorities via metrics etc. During an outage, I noticed that with multiple IP addresses, Linux was using the old obsolete one to send out packets, which does not work with the ISP. With this change, we still hold on to IP addresses for as long as possible, but no longer. fixes issue #57	2020-09-12 19:58:47 +02:00
Michael Stapelberg	93fe6457b3	dnsd: serve DNS on tcp/53 as well (DNS must work over TCP) fixes #59	2020-09-12 19:21:58 +02:00