+ dhcpv6 server; rewrite dhcpv4 server; changed API

AGHTechDoc.md

@@ -12,6 +12,7 @@ Contents:
 * Updating
 	* Get version command
 	* Update command
+* API: Get global status
 * TLS
 	* API: Get TLS configuration
 	* API: Set TLS configuration
@@ -24,6 +25,7 @@ Contents:
 	* API: Find clients by IP
 * DHCP server
 	* DHCP server in DNS
+	* "Show DHCP interfaces" command
 	* "Show DHCP status" command
 	* "Check DHCP" command
 	* "Enable DHCP" command
@@ -376,6 +378,28 @@ Error response:
 UI shows error message "Auto-update has failed"
 
 
+## API: Get global status
+
+Request:
+
+	GET /control/status
+
+Response:
+
+	200 OK
+
+	{
+	"dns_addresses":["..."],
+	"dns_port":53,
+	"http_port":3000,
+	"language":"en",
+	"protection_enabled":true,
+	"running":true,
+	"dhcp_available":true,
+	"version":"undefined"
+	}
+
+
 ## DHCP server
 
 Enable DHCP server algorithm:
@@ -405,6 +429,28 @@ DHCP leases are used in several ways by DNS module.
 		> PTR 100.1.168.192.in-addr.arpa. = bills-notebook.
 
 
+### "Show DHCP interfaces" command
+
+Request:
+
+	GET /control/dhcp/interfaces
+
+Response:
+
+	200 OK
+
+	{
+		"iface_name":{
+			"name":"iface_name",
+			"mtu":1500,
+			"hardware_address":"...",
+			"ip_addresses":["ipv4 addr","ipv6 addr", ...],
+			"flags":"up|broadcast|multicast"
+		}
+		...
+	}
+
+
 ### "Show DHCP status" command
 
 Request:
@@ -416,16 +462,19 @@ Response:
 	200 OK
 
 	{
-		"config":{
+		"enabled":false,
-			"enabled":false,
+		"interface_name":"...",
-			"interface_name":"...",
+		"v4":{
 			"gateway_ip":"...",
 			"subnet_mask":"...",
-			"range_start":"...",
+			"range_start":"...", // if empty: DHCPv4 won't be enabled
 			"range_end":"...",
 			"lease_duration":60,
-			"icmp_timeout_msec":0
 		},
+		"v6":{
+			"range_start":"...", // if empty: DHCPv6 won't be enabled
+			"lease_duration":60,
+		}
 		"leases":[
 			{"ip":"...","mac":"...","hostname":"...","expires":"..."}
 			...
@@ -484,14 +533,19 @@ Request:
 	POST /control/dhcp/set_config
 
 	{
-		"enabled":true,
+	"enabled":true,
-		"interface_name":"vboxnet0",
+	"interface_name":"vboxnet0",
+	"v4":{
 		"gateway_ip":"192.169.56.1",
 		"subnet_mask":"255.255.255.0",
-		"range_start":"192.169.56.3",
+		"range_start":"192.169.56.100",
-		"range_end":"192.169.56.3",
+		"range_end":"192.169.56.200", // Note: first 3 octects must match "range_start"
 		"lease_duration":60,
-		"icmp_timeout_msec":0
+	},
+	"v6":{
+		"range_start":"...",
+		"lease_duration":60,
+	}
 	}
 
 Response:
@@ -500,6 +554,10 @@ Response:
 
 	OK
 
+For v4, if range_start = "1.2.3.4", the range_end must be "1.2.3.X" where X > 4.
+
+For v6, if range_start = "2001::1", the last IP is "2001:ff".
+
 
 ### Static IP check/set
 

dhcpd/check_other_dhcp.go

@@ -1,23 +1,22 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
 package dhcpd
 
 import (
 	"bytes"
-	"crypto/rand"
-	"encoding/binary"
 	"fmt"
-	"math"
 	"net"
 	"os"
 	"time"
 
 	"github.com/AdguardTeam/golibs/log"
-	"github.com/krolaw/dhcp4"
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/iana"
 	"golang.org/x/net/ipv4"
 )
 
 // CheckIfOtherDHCPServersPresent sends a DHCP request to the specified network interface,
 // and waits for a response for a period defined by defaultDiscoverTime
-// nolint
 func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 	iface, err := net.InterfaceByName(ifaceName)
 	if err != nil {
@@ -25,60 +24,29 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 	}
 
 	// get ipv4 address of an interface
-	ifaceIPNet := getIfaceIPv4(iface)
+	ifaceIPNet := getIfaceIPv4(*iface)
-	if ifaceIPNet == nil {
+	if len(ifaceIPNet) == 0 {
-		return false, fmt.Errorf("Couldn't find IPv4 address of interface %s %+v", ifaceName, iface)
+		return false, fmt.Errorf("couldn't find IPv4 address of interface %s %+v", ifaceName, iface)
 	}
 
-	srcIP := ifaceIPNet.IP
+	srcIP := ifaceIPNet[0]
 	src := net.JoinHostPort(srcIP.String(), "68")
 	dst := "255.255.255.255:67"
 
-	// form a DHCP request packet, try to emulate existing client as much as possible
+	hostname, _ := os.Hostname()
-	xID := make([]byte, 4)
+
-	n, err := rand.Read(xID)
+	req, err := dhcpv4.NewDiscovery(iface.HardwareAddr)
-	if n != 4 && err == nil {
-		err = fmt.Errorf("Generated less than 4 bytes")
-	}
 	if err != nil {
-		return false, wrapErrPrint(err, "Couldn't generate random bytes")
+		return false, fmt.Errorf("dhcpv4.NewDiscovery: %s", err)
 	}
-	hostname, err := os.Hostname()
+	req.Options.Update(dhcpv4.OptClientIdentifier(iface.HardwareAddr))
-	if err != nil {
+	req.Options.Update(dhcpv4.OptHostName(hostname))
-		return false, wrapErrPrint(err, "Couldn't get hostname")
-	}
-	requestList := []byte{
-		byte(dhcp4.OptionSubnetMask),
-		byte(dhcp4.OptionClasslessRouteFormat),
-		byte(dhcp4.OptionRouter),
-		byte(dhcp4.OptionDomainNameServer),
-		byte(dhcp4.OptionDomainName),
-		byte(dhcp4.OptionDomainSearch),
-		252, // private/proxy autodiscovery
-		95,  // LDAP
-		byte(dhcp4.OptionNetBIOSOverTCPIPNameServer),
-		byte(dhcp4.OptionNetBIOSOverTCPIPNodeType),
-	}
-	maxUDPsizeRaw := make([]byte, 2)
-	binary.BigEndian.PutUint16(maxUDPsizeRaw, 1500)
-	leaseTimeRaw := make([]byte, 4)
-	leaseTime := uint32(math.RoundToEven((time.Hour * 24 * 90).Seconds()))
-	binary.BigEndian.PutUint32(leaseTimeRaw, leaseTime)
-	options := []dhcp4.Option{
-		{Code: dhcp4.OptionParameterRequestList, Value: requestList},
-		{Code: dhcp4.OptionMaximumDHCPMessageSize, Value: maxUDPsizeRaw},
-		{Code: dhcp4.OptionClientIdentifier, Value: append([]byte{0x01}, iface.HardwareAddr...)},
-		{Code: dhcp4.OptionIPAddressLeaseTime, Value: leaseTimeRaw},
-		{Code: dhcp4.OptionHostName, Value: []byte(hostname)},
-	}
-	packet := dhcp4.RequestPacket(dhcp4.Discover, iface.HardwareAddr, nil, xID, false, options)
 
 	// resolve 0.0.0.0:68
 	udpAddr, err := net.ResolveUDPAddr("udp4", src)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't resolve UDP address %s", src)
 	}
-	// spew.Dump(udpAddr, err)
 
 	if !udpAddr.IP.To4().Equal(srcIP) {
 		return false, wrapErrPrint(err, "Resolved UDP address is not %s", src)
@@ -102,7 +70,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 
 	// send to 255.255.255.255:67
 	cm := ipv4.ControlMessage{}
-	_, err = c.WriteTo(packet, &cm, dstAddr)
+	_, err = c.WriteTo(req.ToBytes(), &cm, dstAddr)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't send a packet to %s", dst)
 	}
@@ -113,7 +81,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 		// TODO: replicate dhclient's behaviour of retrying several times with progressively bigger timeouts
 		b := make([]byte, 1500)
 		_ = c.SetReadDeadline(time.Now().Add(defaultDiscoverTime))
-		n, _, _, err = c.ReadFrom(b)
+		n, _, _, err := c.ReadFrom(b)
 		if isTimeout(err) {
 			// timed out -- no DHCP servers
 			return false, nil
@@ -121,27 +89,24 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 		if err != nil {
 			return false, wrapErrPrint(err, "Couldn't receive packet")
 		}
-		// spew.Dump(n, fromAddr, err, b)
 
 		log.Tracef("Received packet (%v bytes)", n)
 
-		if n < 240 {
+		response, err := dhcpv4.FromBytes(b[:n])
-			// packet too small for dhcp
+		if err != nil {
+			log.Debug("DHCPv4: dhcpv4.FromBytes: %s", err)
 			continue
 		}
 
-		response := dhcp4.Packet(b[:n])
+		log.Debug("DHCPv4: received message from server: %s", response.Summary())
-		if response.OpCode() != dhcp4.BootReply ||
-			response.HType() != 1 /*Ethernet*/ ||
-			response.HLen() > 16 ||
-			!bytes.Equal(response.CHAddr(), iface.HardwareAddr) ||
-			!bytes.Equal(response.XId(), xID) {
-			continue
-		}
 
-		parsedOptions := response.ParseOptions()
+		if !(response.OpCode == dhcpv4.OpcodeBootReply &&
-		if t := parsedOptions[dhcp4.OptionDHCPMessageType]; len(t) != 1 {
+			response.HWType == iana.HWTypeEthernet &&
-			continue //packet without DHCP message type
+			bytes.Equal(response.ClientHWAddr, iface.HardwareAddr) &&
+			bytes.Equal(response.TransactionID[:], req.TransactionID[:]) &&
+			response.Options.Has(dhcpv4.OptionDHCPMessageType)) {
+			log.Debug("DHCPv4: received message from server doesn't match our request")
+			continue
 		}
 
 		log.Tracef("The packet is from an active DHCP server")

dhcpd/check_other_dhcp_windows.go

@@ -0,0 +1,7 @@
+package dhcpd
+
+import "fmt"
+
+func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
+	return false, fmt.Errorf("not supported")
+}

dhcpd/db.go

@@ -11,7 +11,6 @@ import (
 
 	"github.com/AdguardTeam/golibs/file"
 	"github.com/AdguardTeam/golibs/log"
-	"github.com/krolaw/dhcp4"
 )
 
 const dbFilename = "leases.db"
@@ -31,21 +30,12 @@ func normalizeIP(ip net.IP) net.IP {
 	return ip
 }
 
-// Safe version of dhcp4.IPInRange()
-func ipInRange(start, stop, ip net.IP) bool {
-	if len(start) != len(stop) ||
-		len(start) != len(ip) {
-		return false
-	}
-	return dhcp4.IPInRange(start, stop, ip)
-}
-
 // Load lease table from DB
 func (s *Server) dbLoad() {
-	s.leases = nil
-	s.IPpool = make(map[[4]byte]net.HardwareAddr)
 	dynLeases := []*Lease{}
 	staticLeases := []*Lease{}
+	v6StaticLeases := []*Lease{}
+	v6DynLeases := []*Lease{}
 
 	data, err := ioutil.ReadFile(s.conf.DBFilePath)
 	if err != nil {
@@ -66,10 +56,8 @@ func (s *Server) dbLoad() {
 	for i := range obj {
 		obj[i].IP = normalizeIP(obj[i].IP)
 
-		if obj[i].Expiry != leaseExpireStatic &&
+		if !(len(obj[i].IP) == 4 || len(obj[i].IP) == 16) {
-			!ipInRange(s.leaseStart, s.leaseStop, obj[i].IP) {
+			log.Info("DHCP: invalid IP: %s", obj[i].IP)
-
-			log.Tracef("Skipping a lease with IP %v: not within current IP range", obj[i].IP)
 			continue
 		}
 
@@ -80,20 +68,32 @@ func (s *Server) dbLoad() {
 			Expiry:   time.Unix(obj[i].Expiry, 0),
 		}
 
-		if obj[i].Expiry == leaseExpireStatic {
+		if len(obj[i].IP) == 16 {
-			staticLeases = append(staticLeases, &lease)
+			if obj[i].Expiry == leaseExpireStatic {
+				v6StaticLeases = append(v6StaticLeases, &lease)
+			} else {
+				v6DynLeases = append(v6DynLeases, &lease)
+			}
+
 		} else {
-			dynLeases = append(dynLeases, &lease)
+			if obj[i].Expiry == leaseExpireStatic {
+				staticLeases = append(staticLeases, &lease)
+			} else {
+				dynLeases = append(dynLeases, &lease)
+			}
 		}
 	}
 
-	s.leases = normalizeLeases(staticLeases, dynLeases)
+	leases4 := normalizeLeases(staticLeases, dynLeases)
+	s.srv4.ResetLeases(leases4)
 
-	for _, lease := range s.leases {
+	leases6 := normalizeLeases(v6StaticLeases, v6DynLeases)
-		s.reserveIP(lease.IP, lease.HWAddr)
+	if s.srv6 != nil {
+		s.srv6.ResetLeases(leases6)
 	}
 
-	log.Info("DHCP: loaded %d (%d) leases from DB", len(s.leases), numLeases)
+	log.Info("DHCP: loaded leases v4:%d  v6:%d  total-read:%d from DB",
+		len(leases4), len(leases6), numLeases)
 }
 
 // Skip duplicate leases
@@ -127,19 +127,36 @@ func normalizeLeases(staticLeases, dynLeases []*Lease) []*Lease {
 func (s *Server) dbStore() {
 	var leases []leaseJSON
 
-	for i := range s.leases {
+	leases4 := s.srv4.GetLeasesRef()
-		if s.leases[i].Expiry.Unix() == 0 {
+	for _, l := range leases4 {
+		if l.Expiry.Unix() == 0 {
 			continue
 		}
 		lease := leaseJSON{
-			HWAddr:   s.leases[i].HWAddr,
+			HWAddr:   l.HWAddr,
-			IP:       s.leases[i].IP,
+			IP:       l.IP,
-			Hostname: s.leases[i].Hostname,
+			Hostname: l.Hostname,
-			Expiry:   s.leases[i].Expiry.Unix(),
+			Expiry:   l.Expiry.Unix(),
 		}
 		leases = append(leases, lease)
 	}
 
+	if s.srv6 != nil {
+		leases6 := s.srv6.GetLeasesRef()
+		for _, l := range leases6 {
+			if l.Expiry.Unix() == 0 {
+				continue
+			}
+			lease := leaseJSON{
+				HWAddr:   l.HWAddr,
+				IP:       l.IP,
+				Hostname: l.Hostname,
+				Expiry:   l.Expiry.Unix(),
+			}
+			leases = append(leases, lease)
+		}
+	}
+
 	data, err := json.Marshal(leases)
 	if err != nil {
 		log.Error("json.Marshal: %v", err)

dhcpd/dhcp_http.go

@@ -40,13 +40,70 @@ func convertLeases(inputLeases []Lease, includeExpires bool) []map[string]string
 	return leases
 }
 
+type v4ServerConfJSON struct {
+	GatewayIP     string `json:"gateway_ip"`
+	SubnetMask    string `json:"subnet_mask"`
+	RangeStart    string `json:"range_start"`
+	RangeEnd      string `json:"range_end"`
+	LeaseDuration uint32 `json:"lease_duration"`
+}
+
+func v4ServerConfToJSON(c V4ServerConf) v4ServerConfJSON {
+	return v4ServerConfJSON{
+		GatewayIP:     c.GatewayIP,
+		SubnetMask:    c.SubnetMask,
+		RangeStart:    c.RangeStart,
+		RangeEnd:      c.RangeEnd,
+		LeaseDuration: c.LeaseDuration,
+	}
+}
+
+func v4JSONToServerConf(j v4ServerConfJSON) V4ServerConf {
+	return V4ServerConf{
+		GatewayIP:     j.GatewayIP,
+		SubnetMask:    j.SubnetMask,
+		RangeStart:    j.RangeStart,
+		RangeEnd:      j.RangeEnd,
+		LeaseDuration: j.LeaseDuration,
+	}
+}
+
+type v6ServerConfJSON struct {
+	RangeStart    string `json:"range_start"`
+	LeaseDuration uint32 `json:"lease_duration"`
+}
+
+func v6ServerConfToJSON(c V6ServerConf) v6ServerConfJSON {
+	return v6ServerConfJSON{
+		RangeStart:    c.RangeStart,
+		LeaseDuration: c.LeaseDuration,
+	}
+}
+
+func v6JSONToServerConf(j v6ServerConfJSON) V6ServerConf {
+	return V6ServerConf{
+		RangeStart:    j.RangeStart,
+		LeaseDuration: j.LeaseDuration,
+	}
+}
+
 func (s *Server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
 	leases := convertLeases(s.Leases(LeasesDynamic), true)
 	staticLeases := convertLeases(s.Leases(LeasesStatic), false)
+
+	v4conf := V4ServerConf{}
+	s.srv4.WriteDiskConfig4(&v4conf)
+
+	v6conf := V6ServerConf{}
+	s.srv6.WriteDiskConfig6(&v6conf)
+
 	status := map[string]interface{}{
-		"config":        s.conf,
+		"enabled":        s.conf.Enabled,
-		"leases":        leases,
+		"interface_name": s.conf.InterfaceName,
-		"static_leases": staticLeases,
+		"v4":             v4ServerConfToJSON(v4conf),
+		"v6":             v6ServerConfToJSON(v6conf),
+		"leases":         leases,
+		"static_leases":  staticLeases,
 	}
 
 	w.Header().Set("Content-Type", "application/json")
@@ -64,8 +121,10 @@ type staticLeaseJSON struct {
 }
 
 type dhcpServerConfigJSON struct {
-	ServerConfig `json:",inline"`
+	Enabled       bool             `json:"enabled"`
-	StaticLeases []staticLeaseJSON `json:"static_leases"`
+	InterfaceName string           `json:"interface_name"`
+	V4            v4ServerConfJSON `json:"v4"`
+	V6            v6ServerConfJSON `json:"v6"`
 }
 
 func (s *Server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
@@ -76,22 +135,49 @@ func (s *Server) handleDHCPSetConfig(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	err = s.CheckConfig(newconfig.ServerConfig)
+	v4conf := v4JSONToServerConf(newconfig.V4)
+	v4conf.Enabled = newconfig.Enabled
+	if len(v4conf.RangeStart) == 0 {
+		v4conf.Enabled = false
+	}
+	v4conf.InterfaceName = newconfig.InterfaceName
+
+	c4 := V4ServerConf{}
+	s.srv4.WriteDiskConfig4(&c4)
+	v4conf.notify = c4.notify
+	v4conf.ICMPTimeout = c4.ICMPTimeout
+
+	s4, err := v4Create(v4conf)
 	if err != nil {
-		httpError(r, w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
+		httpError(r, w, http.StatusBadRequest, "Invalid DHCPv4 configuration: %s", err)
 		return
 	}
 
-	err = s.Stop()
+	v6conf := v6JSONToServerConf(newconfig.V6)
-	if err != nil {
+	v6conf.Enabled = newconfig.Enabled
-		log.Error("failed to stop the DHCP server: %s", err)
+	if len(v6conf.RangeStart) == 0 {
+		v6conf.Enabled = false
 	}
-
+	v6conf.InterfaceName = newconfig.InterfaceName
-	err = s.Init(newconfig.ServerConfig)
+	v6conf.notify = s.onNotify
-	if err != nil {
+	s6, err := v6Create(v6conf)
-		httpError(r, w, http.StatusBadRequest, "Invalid DHCP configuration: %s", err)
+	if s6 == nil {
+		httpError(r, w, http.StatusBadRequest, "Invalid DHCPv6 configuration: %s", err)
 		return
 	}
+
+	if newconfig.Enabled && !v4conf.Enabled && !v6conf.Enabled {
+		httpError(r, w, http.StatusBadRequest, "DHCPv4 or DHCPv6 configuration must be complete")
+		return
+	}
+
+	s.Stop()
+
+	s.conf.Enabled = newconfig.Enabled
+	s.conf.InterfaceName = newconfig.InterfaceName
+	s.srv4 = s4
+	s.srv6 = s6
+
 	s.conf.ConfigModified()
 
 	if newconfig.Enabled {
@@ -246,20 +332,45 @@ func (s *Server) handleDHCPAddStaticLease(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	ip, _ := parseIPv4(lj.IP)
+	ip := net.ParseIP(lj.IP)
+	if ip != nil && ip.To4() == nil {
+		mac, err := net.ParseMAC(lj.HWAddr)
+		if err != nil {
+			httpError(r, w, http.StatusBadRequest, "invalid MAC")
+			return
+		}
+
+		lease := Lease{
+			IP:     ip,
+			HWAddr: mac,
+		}
+
+		err = s.srv6.AddStaticLease(lease)
+		if err != nil {
+			httpError(r, w, http.StatusBadRequest, "%s", err)
+			return
+		}
+		return
+	}
+
+	ip, _ = parseIPv4(lj.IP)
 	if ip == nil {
 		httpError(r, w, http.StatusBadRequest, "invalid IP")
 		return
 	}
 
-	mac, _ := net.ParseMAC(lj.HWAddr)
+	mac, err := net.ParseMAC(lj.HWAddr)
+	if err != nil {
+		httpError(r, w, http.StatusBadRequest, "invalid MAC")
+		return
+	}
 
 	lease := Lease{
 		IP:       ip,
 		HWAddr:   mac,
 		Hostname: lj.Hostname,
 	}
-	err = s.AddStaticLease(lease)
+	err = s.srv4.AddStaticLease(lease)
 	if err != nil {
 		httpError(r, w, http.StatusBadRequest, "%s", err)
 		return
@@ -275,7 +386,28 @@ func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	ip, _ := parseIPv4(lj.IP)
+	ip := net.ParseIP(lj.IP)
+	if ip != nil && ip.To4() == nil {
+		mac, err := net.ParseMAC(lj.HWAddr)
+		if err != nil {
+			httpError(r, w, http.StatusBadRequest, "invalid MAC")
+			return
+		}
+
+		lease := Lease{
+			IP:     ip,
+			HWAddr: mac,
+		}
+
+		err = s.srv6.RemoveStaticLease(lease)
+		if err != nil {
+			httpError(r, w, http.StatusBadRequest, "%s", err)
+			return
+		}
+		return
+	}
+
+	ip, _ = parseIPv4(lj.IP)
 	if ip == nil {
 		httpError(r, w, http.StatusBadRequest, "invalid IP")
 		return
@@ -288,7 +420,7 @@ func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Requ
 		HWAddr:   mac,
 		Hostname: lj.Hostname,
 	}
-	err = s.RemoveStaticLease(lease)
+	err = s.srv4.RemoveStaticLease(lease)
 	if err != nil {
 		httpError(r, w, http.StatusBadRequest, "%s", err)
 		return
@@ -296,24 +428,29 @@ func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Requ
 }
 
 func (s *Server) handleReset(w http.ResponseWriter, r *http.Request) {
-	err := s.Stop()
+	s.Stop()
-	if err != nil {
-		log.Error("DHCP: Stop: %s", err)
-	}
 
-	err = os.Remove(s.conf.DBFilePath)
+	err := os.Remove(s.conf.DBFilePath)
 	if err != nil && !os.IsNotExist(err) {
 		log.Error("DHCP: os.Remove: %s: %s", s.conf.DBFilePath, err)
 	}
 
 	oldconf := s.conf
 	s.conf = ServerConfig{}
-	s.conf.LeaseDuration = 86400
-	s.conf.ICMPTimeout = 1000
 	s.conf.WorkDir = oldconf.WorkDir
 	s.conf.HTTPRegister = oldconf.HTTPRegister
 	s.conf.ConfigModified = oldconf.ConfigModified
 	s.conf.DBFilePath = oldconf.DBFilePath
+
+	v4conf := V4ServerConf{}
+	v4conf.ICMPTimeout = 1000
+	v4conf.notify = s.onNotify
+	s.srv4, _ = v4Create(v4conf)
+
+	v6conf := V6ServerConf{}
+	v6conf.notify = s.onNotify
+	s.srv6, _ = v6Create(v6conf)
+
 	s.conf.ConfigModified()
 }
 

dhcpd/dhcpd.go

@@ -1,18 +1,12 @@
 package dhcpd
 
 import (
-	"bytes"
-	"fmt"
 	"net"
 	"net/http"
 	"path/filepath"
-	"strings"
-	"sync"
 	"time"
 
 	"github.com/AdguardTeam/golibs/log"
-	"github.com/krolaw/dhcp4"
-	ping "github.com/sparrc/go-ping"
 )
 
 const defaultDiscoverTime = time.Second * 3
@@ -21,9 +15,8 @@ const leaseExpireStatic = 1
 var webHandlersRegistered = false
 
 // Lease contains the necessary information about a DHCP lease
-// field ordering is important -- yaml fields will mirror ordering from here
 type Lease struct {
-	HWAddr   net.HardwareAddr `json:"mac" yaml:"hwaddr"`
+	HWAddr   net.HardwareAddr `json:"mac"`
 	IP       net.IP           `json:"ip"`
 	Hostname string           `json:"hostname"`
 
@@ -35,29 +28,23 @@ type Lease struct {
 // ServerConfig - DHCP server configuration
 // field ordering is important -- yaml fields will mirror ordering from here
 type ServerConfig struct {
-	Enabled       bool   `json:"enabled" yaml:"enabled"`
+	Enabled       bool   `yaml:"enabled"`
-	InterfaceName string `json:"interface_name" yaml:"interface_name"` // eth0, en0 and so on
+	InterfaceName string `yaml:"interface_name"`
-	GatewayIP     string `json:"gateway_ip" yaml:"gateway_ip"`
-	SubnetMask    string `json:"subnet_mask" yaml:"subnet_mask"`
-	RangeStart    string `json:"range_start" yaml:"range_start"`
-	RangeEnd      string `json:"range_end" yaml:"range_end"`
-	LeaseDuration uint32 `json:"lease_duration" yaml:"lease_duration"` // in seconds
 
-	// IP conflict detector: time (ms) to wait for ICMP reply.
+	Conf4 V4ServerConf `yaml:"dhcpv4"`
-	// 0: disable
+	Conf6 V6ServerConf `yaml:"dhcpv6"`
-	ICMPTimeout uint32 `json:"icmp_timeout_msec" yaml:"icmp_timeout_msec"`
 
-	WorkDir    string `json:"-" yaml:"-"`
+	WorkDir    string `yaml:"-"`
-	DBFilePath string `json:"-" yaml:"-"` // path to DB file
+	DBFilePath string `yaml:"-"` // path to DB file
 
 	// Called when the configuration is changed by HTTP request
-	ConfigModified func() `json:"-" yaml:"-"`
+	ConfigModified func() `yaml:"-"`
 
 	// Register an HTTP handler
-	HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `json:"-" yaml:"-"`
+	HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `yaml:"-"`
 }
 
-type onLeaseChangedT func(flags int)
+type OnLeaseChangedT func(flags int)
 
 // flags for onLeaseChanged()
 const (
@@ -65,87 +52,91 @@ const (
 	LeaseChangedAddedStatic
 	LeaseChangedRemovedStatic
 	LeaseChangedBlacklisted
+
+	LeaseChangedDBStore
 )
 
 // Server - the current state of the DHCP server
 type Server struct {
-	conn *filterConn // listening UDP socket
+	srv4 DHCPServer
-
+	srv6 DHCPServer
-	ipnet *net.IPNet // if interface name changes, this needs to be reset
-
-	cond     *sync.Cond // Synchronize worker thread with main thread
-	mutex    sync.Mutex // Mutex for 'cond'
-	running  bool       // Set if the worker thread is running
-	stopping bool       // Set if the worker thread should be stopped
-
-	// leases
-	leases       []*Lease
-	leasesLock   sync.RWMutex
-	leaseStart   net.IP        // parsed from config RangeStart
-	leaseStop    net.IP        // parsed from config RangeEnd
-	leaseTime    time.Duration // parsed from config LeaseDuration
-	leaseOptions dhcp4.Options // parsed from config GatewayIP and SubnetMask
-
-	// IP address pool -- if entry is in the pool, then it's attached to a lease
-	IPpool map[[4]byte]net.HardwareAddr
 
 	conf ServerConfig
 
 	// Called when the leases DB is modified
-	onLeaseChanged []onLeaseChangedT
+	onLeaseChanged []OnLeaseChangedT
 }
 
-// Print information about the available network interfaces
+type ServerInterface interface {
-func printInterfaces() {
+	Leases(flags int) []Lease
-	ifaces, _ := net.Interfaces()
+	SetOnLeaseChanged(onLeaseChanged OnLeaseChangedT)
-	var buf strings.Builder
-	for i := range ifaces {
-		buf.WriteString(fmt.Sprintf("\"%s\", ", ifaces[i].Name))
-	}
-	log.Info("Available network interfaces: %s", buf.String())
 }
 
 // CheckConfig checks the configuration
 func (s *Server) CheckConfig(config ServerConfig) error {
-	tmpServer := Server{}
+	return nil
-	return tmpServer.setConfig(config)
 }
 
 // Create - create object
 func Create(config ServerConfig) *Server {
 	s := Server{}
-	s.conf = config
+	s.conf.Enabled = config.Enabled
+	s.conf.InterfaceName = config.InterfaceName
+	s.conf.HTTPRegister = config.HTTPRegister
+	s.conf.ConfigModified = config.ConfigModified
 	s.conf.DBFilePath = filepath.Join(config.WorkDir, dbFilename)
-	if s.conf.Enabled {
-		err := s.setConfig(config)
-		if err != nil {
-			log.Error("DHCP: %s", err)
-			return nil
-		}
-	}
 
 	if !webHandlersRegistered && s.conf.HTTPRegister != nil {
 		webHandlersRegistered = true
 		s.registerHandlers()
 	}
 
+	var err4, err6 error
+	v4conf := config.Conf4
+	v4conf.Enabled = s.conf.Enabled
+	if len(v4conf.RangeStart) == 0 {
+		v4conf.Enabled = false
+	}
+	v4conf.InterfaceName = s.conf.InterfaceName
+	v4conf.notify = s.onNotify
+	s.srv4, err4 = v4Create(v4conf)
+
+	v6conf := config.Conf6
+	v6conf.Enabled = s.conf.Enabled
+	if len(v6conf.RangeStart) == 0 {
+		v6conf.Enabled = false
+	}
+	v6conf.InterfaceName = s.conf.InterfaceName
+	v6conf.notify = s.onNotify
+	s.srv6, err6 = v6Create(v6conf)
+
+	if err4 != nil {
+		log.Error("%s", err4)
+		return nil
+	}
+	if err6 != nil {
+		log.Error("%s", err6)
+		return nil
+	}
+
 	// we can't delay database loading until DHCP server is started,
 	//  because we need static leases functionality available beforehand
 	s.dbLoad()
 	return &s
 }
 
-// Init checks the configuration and initializes the server
+// server calls this function after DB is updated
-func (s *Server) Init(config ServerConfig) error {
+func (s *Server) onNotify(flags uint32) {
-	err := s.setConfig(config)
+	if flags == LeaseChangedDBStore {
-	if err != nil {
+		s.dbStore()
-		return err
+		return
 	}
-	return nil
+
+	s.notify(int(flags))
 }
 
 // SetOnLeaseChanged - set callback
-func (s *Server) SetOnLeaseChanged(onLeaseChanged onLeaseChangedT) {
+func (s *Server) SetOnLeaseChanged(onLeaseChanged OnLeaseChangedT) {
 	s.onLeaseChanged = append(s.onLeaseChanged, onLeaseChanged)
 }
 
@@ -160,563 +151,33 @@ func (s *Server) notify(flags int) {
 
 // WriteDiskConfig - write configuration
 func (s *Server) WriteDiskConfig(c *ServerConfig) {
-	*c = s.conf
+	c.Enabled = s.conf.Enabled
-}
+	c.InterfaceName = s.conf.InterfaceName
-
+	s.srv4.WriteDiskConfig4(&c.Conf4)
-func (s *Server) setConfig(config ServerConfig) error {
+	s.srv6.WriteDiskConfig6(&c.Conf6)
-	iface, err := net.InterfaceByName(config.InterfaceName)
-	if err != nil {
-		printInterfaces()
-		return wrapErrPrint(err, "Couldn't find interface by name %s", config.InterfaceName)
-	}
-
-	// get ipv4 address of an interface
-	s.ipnet = getIfaceIPv4(iface)
-	if s.ipnet == nil {
-		return wrapErrPrint(err, "Couldn't find IPv4 address of interface %s %+v", config.InterfaceName, iface)
-	}
-
-	if config.LeaseDuration == 0 {
-		s.leaseTime = time.Hour * 2
-	} else {
-		s.leaseTime = time.Second * time.Duration(config.LeaseDuration)
-	}
-
-	s.leaseStart, err = parseIPv4(config.RangeStart)
-	if err != nil {
-		return wrapErrPrint(err, "Failed to parse range start address %s", config.RangeStart)
-	}
-
-	s.leaseStop, err = parseIPv4(config.RangeEnd)
-	if err != nil {
-		return wrapErrPrint(err, "Failed to parse range end address %s", config.RangeEnd)
-	}
-	if dhcp4.IPRange(s.leaseStart, s.leaseStop) <= 0 {
-		return wrapErrPrint(err, "DHCP: Incorrect range_start/range_end values")
-	}
-
-	subnet, err := parseIPv4(config.SubnetMask)
-	if err != nil || !isValidSubnetMask(subnet) {
-		return wrapErrPrint(err, "Failed to parse subnet mask %s", config.SubnetMask)
-	}
-
-	// if !bytes.Equal(subnet, s.ipnet.Mask) {
-	// 	return wrapErrPrint(err, "specified subnet mask %s does not meatch interface %s subnet mask %s", s.SubnetMask, s.InterfaceName, s.ipnet.Mask)
-	// }
-
-	router, err := parseIPv4(config.GatewayIP)
-	if err != nil {
-		return wrapErrPrint(err, "Failed to parse gateway IP %s", config.GatewayIP)
-	}
-
-	s.leaseOptions = dhcp4.Options{
-		dhcp4.OptionSubnetMask:       subnet,
-		dhcp4.OptionRouter:           router,
-		dhcp4.OptionDomainNameServer: s.ipnet.IP,
-	}
-
-	oldconf := s.conf
-	s.conf = config
-	s.conf.WorkDir = oldconf.WorkDir
-	s.conf.HTTPRegister = oldconf.HTTPRegister
-	s.conf.ConfigModified = oldconf.ConfigModified
-	s.conf.DBFilePath = oldconf.DBFilePath
-	return nil
 }
 
 // Start will listen on port 67 and serve DHCP requests.
 func (s *Server) Start() error {
-	// TODO: don't close if interface and addresses are the same
+	err := s.srv4.Start()
-	if s.conn != nil {
-		_ = s.closeConn()
-	}
-
-	iface, err := net.InterfaceByName(s.conf.InterfaceName)
 	if err != nil {
-		return wrapErrPrint(err, "Couldn't find interface by name %s", s.conf.InterfaceName)
+		log.Error("DHCPv4: start: %s", err)
+		return err
 	}
 
-	c, err := newFilterConn(*iface, ":67") // it has to be bound to 0.0.0.0:67, otherwise it won't see DHCP discover/request packets
+	err = s.srv6.Start()
 	if err != nil {
-		return wrapErrPrint(err, "Couldn't start listening socket on 0.0.0.0:67")
+		log.Error("DHCPv6: start: %s", err)
+		return err
 	}
-	log.Info("DHCP: listening on 0.0.0.0:67")
-
-	s.conn = c
-	s.cond = sync.NewCond(&s.mutex)
-
-	s.running = true
-	go func() {
-		// operate on c instead of c.conn because c.conn can change over time
-		err := dhcp4.Serve(c, s)
-		if err != nil && !s.stopping {
-			log.Printf("dhcp4.Serve() returned with error: %s", err)
-		}
-		_ = c.Close() // in case Serve() exits for other reason than listening socket closure
-		s.running = false
-		s.cond.Signal()
-	}()
 
 	return nil
 }
 
 // Stop closes the listening UDP socket
-func (s *Server) Stop() error {
+func (s *Server) Stop() {
-	if s.conn == nil {
+	s.srv4.Stop()
-		// nothing to do, return silently
+	s.srv6.Stop()
-		return nil
-	}
-
-	s.stopping = true
-
-	err := s.closeConn()
-	if err != nil {
-		return wrapErrPrint(err, "Couldn't close UDP listening socket")
-	}
-
-	// We've just closed the listening socket.
-	// Worker thread should exit right after it tries to read from the socket.
-	s.mutex.Lock()
-	for s.running {
-		s.cond.Wait()
-	}
-	s.mutex.Unlock()
-	return nil
-}
-
-// closeConn will close the connection and set it to zero
-func (s *Server) closeConn() error {
-	if s.conn == nil {
-		return nil
-	}
-	err := s.conn.Close()
-	s.conn = nil
-	return err
-}
-
-// Reserve a lease for the client
-func (s *Server) reserveLease(p dhcp4.Packet) (*Lease, error) {
-	// WARNING: do not remove copy()
-	// the given hwaddr by p.CHAddr() in the packet survives only during ServeDHCP() call
-	// since we need to retain it we need to make our own copy
-	hwaddrCOW := p.CHAddr()
-	hwaddr := make(net.HardwareAddr, len(hwaddrCOW))
-	copy(hwaddr, hwaddrCOW)
-	// not assigned a lease, create new one, find IP from LRU
-	hostname := p.ParseOptions()[dhcp4.OptionHostName]
-	lease := &Lease{HWAddr: hwaddr, Hostname: string(hostname)}
-
-	log.Tracef("Lease not found for %s: creating new one", hwaddr)
-
-	s.leasesLock.Lock()
-	defer s.leasesLock.Unlock()
-
-	ip, err := s.findFreeIP(hwaddr)
-	if err != nil {
-		i := s.findExpiredLease()
-		if i < 0 {
-			return nil, wrapErrPrint(err, "Couldn't find free IP for the lease %s", hwaddr.String())
-		}
-
-		log.Tracef("Assigning IP address %s to %s (lease for %s expired at %s)",
-			s.leases[i].IP, hwaddr, s.leases[i].HWAddr, s.leases[i].Expiry)
-		lease.IP = s.leases[i].IP
-		s.leases[i] = lease
-
-		s.reserveIP(lease.IP, hwaddr)
-		return lease, nil
-	}
-
-	log.Tracef("Assigning to %s IP address %s", hwaddr, ip.String())
-	lease.IP = ip
-	s.leases = append(s.leases, lease)
-	return lease, nil
-}
-
-// Find a lease for the client
-func (s *Server) findLease(p dhcp4.Packet) *Lease {
-	hwaddr := p.CHAddr()
-	for i := range s.leases {
-		if bytes.Equal([]byte(hwaddr), []byte(s.leases[i].HWAddr)) {
-			// log.Tracef("bytes.Equal(%s, %s) returned true", hwaddr, s.leases[i].hwaddr)
-			return s.leases[i]
-		}
-	}
-	return nil
-}
-
-// Find an expired lease and return its index or -1
-func (s *Server) findExpiredLease() int {
-	now := time.Now().Unix()
-	for i, lease := range s.leases {
-		if lease.Expiry.Unix() <= now && lease.Expiry.Unix() != leaseExpireStatic {
-			return i
-		}
-	}
-	return -1
-}
-
-func (s *Server) findFreeIP(hwaddr net.HardwareAddr) (net.IP, error) {
-	// go from start to end, find unreserved IP
-	var foundIP net.IP
-	for i := 0; i < dhcp4.IPRange(s.leaseStart, s.leaseStop); i++ {
-		newIP := dhcp4.IPAdd(s.leaseStart, i)
-		foundHWaddr := s.findReservedHWaddr(newIP)
-		log.Tracef("tried IP %v, got hwaddr %v", newIP, foundHWaddr)
-		if foundHWaddr != nil && len(foundHWaddr) != 0 {
-			// if !bytes.Equal(foundHWaddr, hwaddr) {
-			// 	log.Tracef("SHOULD NOT HAPPEN: hwaddr in IP pool %s is not equal to hwaddr in lease %s", foundHWaddr, hwaddr)
-			// }
-			continue
-		}
-		foundIP = newIP
-		break
-	}
-
-	if foundIP == nil {
-		// TODO: LRU
-		return nil, fmt.Errorf("couldn't find free entry in IP pool")
-	}
-
-	s.reserveIP(foundIP, hwaddr)
-
-	return foundIP, nil
-}
-
-func (s *Server) findReservedHWaddr(ip net.IP) net.HardwareAddr {
-	rawIP := []byte(ip)
-	IP4 := [4]byte{rawIP[0], rawIP[1], rawIP[2], rawIP[3]}
-	return s.IPpool[IP4]
-}
-
-func (s *Server) reserveIP(ip net.IP, hwaddr net.HardwareAddr) {
-	rawIP := []byte(ip)
-	IP4 := [4]byte{rawIP[0], rawIP[1], rawIP[2], rawIP[3]}
-	s.IPpool[IP4] = hwaddr
-}
-
-func (s *Server) unreserveIP(ip net.IP) {
-	rawIP := []byte(ip)
-	IP4 := [4]byte{rawIP[0], rawIP[1], rawIP[2], rawIP[3]}
-	delete(s.IPpool, IP4)
-}
-
-// ServeDHCP handles an incoming DHCP request
-func (s *Server) ServeDHCP(p dhcp4.Packet, msgType dhcp4.MessageType, options dhcp4.Options) dhcp4.Packet {
-	s.printLeases()
-
-	switch msgType {
-	case dhcp4.Discover: // Broadcast Packet From Client - Can I have an IP?
-		return s.handleDiscover(p, options)
-
-	case dhcp4.Request: // Broadcast From Client - I'll take that IP (Also start for renewals)
-		// start/renew a lease -- update lease time
-		// some clients (OSX) just go right ahead and do Request first from previously known IP, if they get NAK, they restart full cycle with Discover then Request
-		return s.handleDHCP4Request(p, options)
-
-	case dhcp4.Decline: // Broadcast From Client - Sorry I can't use that IP
-		return s.handleDecline(p, options)
-
-	case dhcp4.Release: // From Client, I don't need that IP anymore
-		return s.handleRelease(p, options)
-
-	case dhcp4.Inform: // From Client, I have this IP and there's nothing you can do about it
-		return s.handleInform(p, options)
-
-	// from server -- ignore those but enumerate just in case
-	case dhcp4.Offer: // Broadcast From Server - Here's an IP
-		log.Printf("DHCP: received message from %s: Offer", p.CHAddr())
-
-	case dhcp4.ACK: // From Server, Yes you can have that IP
-		log.Printf("DHCP: received message from %s: ACK", p.CHAddr())
-
-	case dhcp4.NAK: // From Server, No you cannot have that IP
-		log.Printf("DHCP: received message from %s: NAK", p.CHAddr())
-
-	default:
-		log.Printf("DHCP: unknown packet %v from %s", msgType, p.CHAddr())
-		return nil
-	}
-	return nil
-}
-
-// Send ICMP to the specified machine
-// Return TRUE if it doesn't reply, which probably means that the IP is available
-func (s *Server) addrAvailable(target net.IP) bool {
-
-	if s.conf.ICMPTimeout == 0 {
-		return true
-	}
-
-	pinger, err := ping.NewPinger(target.String())
-	if err != nil {
-		log.Error("ping.NewPinger(): %v", err)
-		return true
-	}
-
-	pinger.SetPrivileged(true)
-	pinger.Timeout = time.Duration(s.conf.ICMPTimeout) * time.Millisecond
-	pinger.Count = 1
-	reply := false
-	pinger.OnRecv = func(pkt *ping.Packet) {
-		// log.Tracef("Received ICMP Reply from %v", target)
-		reply = true
-	}
-	log.Tracef("Sending ICMP Echo to %v", target)
-	pinger.Run()
-
-	if reply {
-		log.Info("DHCP: IP conflict: %v is already used by another device", target)
-		return false
-	}
-
-	log.Tracef("ICMP procedure is complete: %v", target)
-	return true
-}
-
-// Add the specified IP to the black list for a time period
-func (s *Server) blacklistLease(lease *Lease) {
-	hw := make(net.HardwareAddr, 6)
-	s.leasesLock.Lock()
-	s.reserveIP(lease.IP, hw)
-	lease.HWAddr = hw
-	lease.Hostname = ""
-	lease.Expiry = time.Now().Add(s.leaseTime)
-	s.dbStore()
-	s.leasesLock.Unlock()
-	s.notify(LeaseChangedBlacklisted)
-}
-
-// Return TRUE if DHCP packet is correct
-func isValidPacket(p dhcp4.Packet) bool {
-	hw := p.CHAddr()
-	zeroes := make([]byte, len(hw))
-	if bytes.Equal(hw, zeroes) {
-		log.Tracef("Packet has empty CHAddr")
-		return false
-	}
-	return true
-}
-
-func (s *Server) handleDiscover(p dhcp4.Packet, options dhcp4.Options) dhcp4.Packet {
-	// find a lease, but don't update lease time
-	var lease *Lease
-	var err error
-
-	reqIP := net.IP(options[dhcp4.OptionRequestedIPAddress])
-	hostname := p.ParseOptions()[dhcp4.OptionHostName]
-	log.Tracef("Message from client: Discover.  ReqIP: %s  HW: %s  Hostname: %s",
-		reqIP, p.CHAddr(), hostname)
-
-	if !isValidPacket(p) {
-		return nil
-	}
-
-	lease = s.findLease(p)
-	for lease == nil {
-		lease, err = s.reserveLease(p)
-		if err != nil {
-			log.Error("Couldn't find free lease: %s", err)
-			return nil
-		}
-
-		if !s.addrAvailable(lease.IP) {
-			s.blacklistLease(lease)
-			lease = nil
-			continue
-		}
-
-		break
-	}
-
-	opt := s.leaseOptions.SelectOrderOrAll(options[dhcp4.OptionParameterRequestList])
-	reply := dhcp4.ReplyPacket(p, dhcp4.Offer, s.ipnet.IP, lease.IP, s.leaseTime, opt)
-	log.Tracef("Replying with offer: offered IP %v for %v with options %+v", lease.IP, s.leaseTime, reply.ParseOptions())
-	return reply
-}
-
-func (s *Server) handleDHCP4Request(p dhcp4.Packet, options dhcp4.Options) dhcp4.Packet {
-	var lease *Lease
-
-	reqIP := net.IP(options[dhcp4.OptionRequestedIPAddress])
-	log.Tracef("Message from client: Request.  IP: %s  ReqIP: %s  HW: %s",
-		p.CIAddr(), reqIP, p.CHAddr())
-
-	if !isValidPacket(p) {
-		return nil
-	}
-
-	server := options[dhcp4.OptionServerIdentifier]
-	if server != nil && !net.IP(server).Equal(s.ipnet.IP) {
-		log.Tracef("Request message not for this DHCP server (%v vs %v)", server, s.ipnet.IP)
-		return nil // Message not for this dhcp server
-	}
-
-	if reqIP == nil {
-		reqIP = p.CIAddr()
-
-	} else if reqIP == nil || reqIP.To4() == nil {
-		log.Tracef("Requested IP isn't a valid IPv4: %s", reqIP)
-		return dhcp4.ReplyPacket(p, dhcp4.NAK, s.ipnet.IP, nil, 0, nil)
-	}
-
-	lease = s.findLease(p)
-	if lease == nil {
-		log.Tracef("Lease for %s isn't found", p.CHAddr())
-		return dhcp4.ReplyPacket(p, dhcp4.NAK, s.ipnet.IP, nil, 0, nil)
-	}
-
-	if !lease.IP.Equal(reqIP) {
-		log.Tracef("Lease for %s doesn't match requested/client IP: %s vs %s",
-			lease.HWAddr, lease.IP, reqIP)
-		return dhcp4.ReplyPacket(p, dhcp4.NAK, s.ipnet.IP, nil, 0, nil)
-	}
-
-	if lease.Expiry.Unix() != leaseExpireStatic {
-		lease.Expiry = time.Now().Add(s.leaseTime)
-		s.leasesLock.Lock()
-		s.dbStore()
-		s.leasesLock.Unlock()
-		s.notify(LeaseChangedAdded) // Note: maybe we shouldn't call this function if only expiration time is updated
-	}
-	log.Tracef("Replying with ACK.  IP: %s  HW: %s  Expire: %s",
-		lease.IP, lease.HWAddr, lease.Expiry)
-	opt := s.leaseOptions.SelectOrderOrAll(options[dhcp4.OptionParameterRequestList])
-	return dhcp4.ReplyPacket(p, dhcp4.ACK, s.ipnet.IP, lease.IP, s.leaseTime, opt)
-}
-
-func (s *Server) handleInform(p dhcp4.Packet, options dhcp4.Options) dhcp4.Packet {
-	log.Tracef("Message from client: Inform.  IP: %s  HW: %s",
-		p.CIAddr(), p.CHAddr())
-
-	return nil
-}
-
-func (s *Server) handleRelease(p dhcp4.Packet, options dhcp4.Options) dhcp4.Packet {
-	log.Tracef("Message from client: Release.  IP: %s  HW: %s",
-		p.CIAddr(), p.CHAddr())
-
-	return nil
-}
-
-func (s *Server) handleDecline(p dhcp4.Packet, options dhcp4.Options) dhcp4.Packet {
-	reqIP := net.IP(options[dhcp4.OptionRequestedIPAddress])
-	log.Tracef("Message from client: Decline.  IP: %s  HW: %s",
-		reqIP, p.CHAddr())
-
-	return nil
-}
-
-// AddStaticLease adds a static lease (thread-safe)
-func (s *Server) AddStaticLease(l Lease) error {
-	if len(l.IP) != 4 {
-		return fmt.Errorf("invalid IP")
-	}
-	if len(l.HWAddr) != 6 {
-		return fmt.Errorf("invalid MAC")
-	}
-	l.Expiry = time.Unix(leaseExpireStatic, 0)
-
-	s.leasesLock.Lock()
-
-	if s.findReservedHWaddr(l.IP) != nil {
-		err := s.rmDynamicLeaseWithIP(l.IP)
-		if err != nil {
-			s.leasesLock.Unlock()
-			return err
-		}
-	} else {
-		err := s.rmDynamicLeaseWithMAC(l.HWAddr)
-		if err != nil {
-			s.leasesLock.Unlock()
-			return err
-		}
-	}
-	s.leases = append(s.leases, &l)
-	s.reserveIP(l.IP, l.HWAddr)
-	s.dbStore()
-	s.leasesLock.Unlock()
-	s.notify(LeaseChangedAddedStatic)
-	return nil
-}
-
-// Remove a dynamic lease by IP address
-func (s *Server) rmDynamicLeaseWithIP(ip net.IP) error {
-	var newLeases []*Lease
-	for _, lease := range s.leases {
-		if net.IP.Equal(lease.IP.To4(), ip) {
-			if lease.Expiry.Unix() == leaseExpireStatic {
-				return fmt.Errorf("static lease with the same IP already exists")
-			}
-			continue
-		}
-		newLeases = append(newLeases, lease)
-	}
-	s.leases = newLeases
-	s.unreserveIP(ip)
-	return nil
-}
-
-// Remove a dynamic lease by IP address
-func (s *Server) rmDynamicLeaseWithMAC(mac net.HardwareAddr) error {
-	var newLeases []*Lease
-	for _, lease := range s.leases {
-		if bytes.Equal(lease.HWAddr, mac) {
-			if lease.Expiry.Unix() == leaseExpireStatic {
-				return fmt.Errorf("static lease with the same IP already exists")
-			}
-			s.unreserveIP(lease.IP)
-			continue
-		}
-		newLeases = append(newLeases, lease)
-	}
-	s.leases = newLeases
-	return nil
-}
-
-// Remove a lease
-func (s *Server) rmLease(l Lease) error {
-	var newLeases []*Lease
-	for _, lease := range s.leases {
-		if net.IP.Equal(lease.IP.To4(), l.IP) {
-			if !bytes.Equal(lease.HWAddr, l.HWAddr) ||
-				lease.Hostname != l.Hostname {
-				return fmt.Errorf("Lease not found")
-			}
-			continue
-		}
-		newLeases = append(newLeases, lease)
-	}
-	s.leases = newLeases
-	s.unreserveIP(l.IP)
-	return nil
-}
-
-// RemoveStaticLease removes a static lease (thread-safe)
-func (s *Server) RemoveStaticLease(l Lease) error {
-	if len(l.IP) != 4 {
-		return fmt.Errorf("invalid IP")
-	}
-	if len(l.HWAddr) != 6 {
-		return fmt.Errorf("invalid MAC")
-	}
-
-	s.leasesLock.Lock()
-
-	if s.findReservedHWaddr(l.IP) == nil {
-		s.leasesLock.Unlock()
-		return fmt.Errorf("lease not found")
-	}
-
-	err := s.rmLease(l)
-	if err != nil {
-		s.leasesLock.Unlock()
-		return err
-	}
-	s.dbStore()
-	s.leasesLock.Unlock()
-	s.notify(LeaseChangedRemovedStatic)
-	return nil
 }
 
 // flags for Leases() function
@@ -728,69 +189,23 @@ const (
 
 // Leases returns the list of current DHCP leases (thread-safe)
 func (s *Server) Leases(flags int) []Lease {
-	var result []Lease
+	result := s.srv4.GetLeases(flags)
-	now := time.Now().Unix()
+
-	s.leasesLock.RLock()
+	v6leases := s.srv6.GetLeases(flags)
-	for _, lease := range s.leases {
+	result = append(result, v6leases...)
-		if ((flags&LeasesDynamic) != 0 && lease.Expiry.Unix() > now) ||
-			((flags&LeasesStatic) != 0 && lease.Expiry.Unix() == leaseExpireStatic) {
-			result = append(result, *lease)
-		}
-	}
-	s.leasesLock.RUnlock()
 
 	return result
 }
 
-// Print information about the current leases
-func (s *Server) printLeases() {
-	log.Tracef("Leases:")
-	for i, lease := range s.leases {
-		log.Tracef("Lease #%d: hwaddr %s, ip %s, expiry %s",
-			i, lease.HWAddr, lease.IP, lease.Expiry)
-	}
-}
-
-// FindIPbyMAC finds an IP address by MAC address in the currently active DHCP leases
-func (s *Server) FindIPbyMAC(mac net.HardwareAddr) net.IP {
-	now := time.Now().Unix()
-	s.leasesLock.RLock()
-	defer s.leasesLock.RUnlock()
-	for _, l := range s.leases {
-		if l.Expiry.Unix() > now && bytes.Equal(mac, l.HWAddr) {
-			return l.IP
-		}
-	}
-	return nil
-}
-
 // FindMACbyIP - find a MAC address by IP address in the currently active DHCP leases
 func (s *Server) FindMACbyIP(ip net.IP) net.HardwareAddr {
-	now := time.Now().Unix()
+	if ip.To4() != nil {
-
+		return s.srv4.FindMACbyIP(ip)
-	s.leasesLock.RLock()
-	defer s.leasesLock.RUnlock()
-
-	ip4 := ip.To4()
-	if ip4 == nil {
-		return nil
 	}
-
+	return s.srv6.FindMACbyIP(ip)
-	for _, l := range s.leases {
-		if l.IP.Equal(ip4) {
-			unix := l.Expiry.Unix()
-			if unix > now || unix == leaseExpireStatic {
-				return l.HWAddr
-			}
-		}
-	}
-	return nil
 }
 
-// Reset internal state
+// AddStaticLease - add static v4 lease
-func (s *Server) reset() {
+func (s *Server) AddStaticLease(lease Lease) error {
-	s.leasesLock.Lock()
+	return s.srv4.AddStaticLease(lease)
-	s.leases = nil
-	s.IPpool = make(map[[4]byte]net.HardwareAddr)
-	s.leasesLock.Unlock()
 }

dhcpd/dhcpd_test.go

@@ -1,3 +1,5 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
 package dhcpd
 
 import (
@@ -7,7 +9,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/krolaw/dhcp4"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -17,234 +18,66 @@ func check(t *testing.T, result bool, msg string) {
 	}
 }
 
-// Tests performed:
+func testNotify(flags uint32) {
-// . Handle Discover message (lease reserve)
-// . Handle Request message (lease commit)
-// . Static leases
-func TestDHCP(t *testing.T) {
-	var s = Server{}
-	s.conf.DBFilePath = dbFilename
-	defer func() { _ = os.Remove(dbFilename) }()
-	var p, p2 dhcp4.Packet
-	var hw net.HardwareAddr
-	var lease *Lease
-	var opt dhcp4.Options
-
-	s.reset()
-	s.leaseStart = []byte{1, 1, 1, 1}
-	s.leaseStop = []byte{1, 1, 1, 2}
-	s.leaseTime = 5 * time.Second
-	s.leaseOptions = dhcp4.Options{}
-	s.ipnet = &net.IPNet{
-		IP:   []byte{1, 2, 3, 4},
-		Mask: []byte{0xff, 0xff, 0xff, 0xff},
-	}
-
-	p = make(dhcp4.Packet, 241)
-
-	// Discover and reserve an IP
-	hw = []byte{3, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	p.SetCIAddr([]byte{0, 0, 0, 0})
-	opt = make(dhcp4.Options, 10)
-	p2 = s.handleDiscover(p, opt)
-	opt = p2.ParseOptions()
-	check(t, bytes.Equal(opt[dhcp4.OptionDHCPMessageType], []byte{byte(dhcp4.Offer)}), "dhcp4.Offer")
-	check(t, bytes.Equal(p2.YIAddr(), []byte{1, 1, 1, 1}), "p2.YIAddr")
-	check(t, bytes.Equal(p2.CHAddr(), hw), "p2.CHAddr")
-	check(t, bytes.Equal(opt[dhcp4.OptionIPAddressLeaseTime], dhcp4.OptionsLeaseTime(5*time.Second)), "OptionIPAddressLeaseTime")
-	check(t, bytes.Equal(opt[dhcp4.OptionServerIdentifier], s.ipnet.IP), "OptionServerIdentifier")
-
-	lease = s.findLease(p)
-	check(t, bytes.Equal(lease.HWAddr, hw), "lease.HWAddr")
-	check(t, bytes.Equal(lease.IP, []byte{1, 1, 1, 1}), "lease.IP")
-
-	// Reserve an IP - the next IP from the range
-	hw = []byte{2, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	lease, _ = s.reserveLease(p)
-	check(t, bytes.Equal(lease.HWAddr, hw), "lease.HWAddr")
-	check(t, bytes.Equal(lease.IP, []byte{1, 1, 1, 2}), "lease.IP")
-
-	// Reserve an IP - we have no more available IPs,
-	//  so the first expired (or, in our case, not yet committed) lease is returned
-	hw = []byte{1, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	lease, _ = s.reserveLease(p)
-	check(t, bytes.Equal(lease.HWAddr, hw), "lease.HWAddr")
-	check(t, bytes.Equal(lease.IP, []byte{1, 1, 1, 1}), "lease.IP")
-
-	// Decline request for a lease which doesn't match our internal state
-	hw = []byte{1, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	p.SetCIAddr([]byte{0, 0, 0, 0})
-	opt = make(dhcp4.Options, 10)
-	// ask a different IP
-	opt[dhcp4.OptionRequestedIPAddress] = []byte{1, 1, 1, 2}
-	p2 = s.handleDHCP4Request(p, opt)
-	opt = p2.ParseOptions()
-	check(t, bytes.Equal(opt[dhcp4.OptionDHCPMessageType], []byte{byte(dhcp4.NAK)}), "dhcp4.NAK")
-
-	// Commit the previously reserved lease
-	hw = []byte{1, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	p.SetCIAddr([]byte{0, 0, 0, 0})
-	opt = make(dhcp4.Options, 10)
-	opt[dhcp4.OptionRequestedIPAddress] = []byte{1, 1, 1, 1}
-	p2 = s.handleDHCP4Request(p, opt)
-	opt = p2.ParseOptions()
-	check(t, bytes.Equal(opt[dhcp4.OptionDHCPMessageType], []byte{byte(dhcp4.ACK)}), "dhcp4.ACK")
-	check(t, bytes.Equal(p2.YIAddr(), []byte{1, 1, 1, 1}), "p2.YIAddr")
-	check(t, bytes.Equal(p2.CHAddr(), hw), "p2.CHAddr")
-	check(t, bytes.Equal(opt[dhcp4.OptionIPAddressLeaseTime], dhcp4.OptionsLeaseTime(5*time.Second)), "OptionIPAddressLeaseTime")
-	check(t, bytes.Equal(opt[dhcp4.OptionServerIdentifier], s.ipnet.IP), "OptionServerIdentifier")
-
-	check(t, bytes.Equal(s.FindIPbyMAC(hw), []byte{1, 1, 1, 1}), "FindIPbyMAC")
-
-	// Commit the previously reserved lease #2
-	hw = []byte{2, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	p.SetCIAddr([]byte{0, 0, 0, 0})
-	opt = make(dhcp4.Options, 10)
-	opt[dhcp4.OptionRequestedIPAddress] = []byte{1, 1, 1, 2}
-	p2 = s.handleDHCP4Request(p, opt)
-	check(t, bytes.Equal(p2.YIAddr(), []byte{1, 1, 1, 2}), "p2.YIAddr")
-
-	// Reserve an IP - we have no more available IPs
-	hw = []byte{3, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	lease, _ = s.reserveLease(p)
-	check(t, lease == nil, "lease == nil")
-
-	s.reset()
-	testStaticLeases(t, &s)
-	testStaticLeaseReplaceByMAC(t, &s)
-
-	s.reset()
-	misc(t, &s)
-}
-
-func testStaticLeases(t *testing.T, s *Server) {
-	var err error
-	var l Lease
-	l.IP = []byte{1, 1, 1, 1}
-
-	l.HWAddr = []byte{1, 2, 3, 4, 5, 6}
-	s.leases = append(s.leases, &l)
-
-	// replace dynamic lease with a static (same IP)
-	l.HWAddr = []byte{2, 2, 3, 4, 5, 6}
-	err = s.AddStaticLease(l)
-	check(t, err == nil, "AddStaticLease")
-
-	ll := s.Leases(LeasesAll)
-	assert.True(t, len(ll) == 1)
-	assert.True(t, bytes.Equal(ll[0].IP, []byte{1, 1, 1, 1}))
-	assert.True(t, bytes.Equal(ll[0].HWAddr, []byte{2, 2, 3, 4, 5, 6}))
-	assert.True(t, ll[0].Expiry.Unix() == leaseExpireStatic)
-
-	err = s.RemoveStaticLease(l)
-	assert.True(t, err == nil)
-
-	ll = s.Leases(LeasesAll)
-	assert.True(t, len(ll) == 0)
-}
-
-func testStaticLeaseReplaceByMAC(t *testing.T, s *Server) {
-	var err error
-	var l Lease
-	l.HWAddr = []byte{1, 2, 3, 4, 5, 6}
-
-	l.IP = []byte{1, 1, 1, 1}
-	l.Expiry = time.Now().Add(time.Hour)
-	s.leases = append(s.leases, &l)
-
-	// replace dynamic lease with a static (same MAC)
-	l.IP = []byte{2, 1, 1, 1}
-	err = s.AddStaticLease(l)
-	assert.True(t, err == nil)
-
-	ll := s.Leases(LeasesAll)
-	assert.True(t, len(ll) == 1)
-	assert.True(t, bytes.Equal(ll[0].IP, []byte{2, 1, 1, 1}))
-	assert.True(t, bytes.Equal(ll[0].HWAddr, []byte{1, 2, 3, 4, 5, 6}))
-}
-
-// Small tests that don't require a static server's state
-func misc(t *testing.T, s *Server) {
-	var p, p2 dhcp4.Packet
-	var hw net.HardwareAddr
-	var opt dhcp4.Options
-
-	p = make(dhcp4.Packet, 241)
-
-	// Try to commit a lease for an IP without prior Discover-Offer packets
-	hw = []byte{2, 2, 3, 4, 5, 6}
-	p.SetCHAddr(hw)
-	p.SetCIAddr([]byte{0, 0, 0, 0})
-	opt = make(dhcp4.Options, 10)
-	opt[dhcp4.OptionRequestedIPAddress] = []byte{1, 1, 1, 1}
-	p2 = s.handleDHCP4Request(p, opt)
-	opt = p2.ParseOptions()
-	check(t, bytes.Equal(opt[dhcp4.OptionDHCPMessageType], []byte{byte(dhcp4.NAK)}), "dhcp4.NAK")
 }
 
 // Leases database store/load
 func TestDB(t *testing.T) {
-	var s = Server{}
+	var err error
+	s := Server{}
 	s.conf.DBFilePath = dbFilename
-	var p dhcp4.Packet
-	var hw1, hw2 net.HardwareAddr
-	var lease *Lease
 
-	s.reset()
+	conf := V4ServerConf{
-	s.leaseStart = []byte{1, 1, 1, 1}
+		Enabled:    true,
-	s.leaseStop = []byte{1, 1, 1, 2}
+		RangeStart: "192.168.10.100",
-	s.leaseTime = 5 * time.Second
+		RangeEnd:   "192.168.10.200",
-	s.leaseOptions = dhcp4.Options{}
+		GatewayIP:  "192.168.10.1",
-	s.ipnet = &net.IPNet{
+		SubnetMask: "255.255.255.0",
-		IP:   []byte{1, 2, 3, 4},
+		notify:     testNotify,
-		Mask: []byte{0xff, 0xff, 0xff, 0xff},
 	}
+	s.srv4, err = v4Create(conf)
+	assert.True(t, err == nil)
 
-	p = make(dhcp4.Packet, 241)
+	s.srv6, err = v6Create(V6ServerConf{})
+	assert.True(t, err == nil)
 
-	hw1 = []byte{1, 2, 3, 4, 5, 6}
+	l := Lease{}
-	p.SetCHAddr(hw1)
+	l.IP = net.ParseIP("192.168.10.100").To4()
-	lease, _ = s.reserveLease(p)
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
-	lease.Expiry = time.Unix(4000000001, 0)
+	exp1 := time.Now().Add(time.Hour)
+	l.Expiry = exp1
+	s.srv4.(*v4Server).addLease(&l)
 
-	hw2 = []byte{2, 2, 3, 4, 5, 6}
+	l2 := Lease{}
-	p.SetCHAddr(hw2)
+	l2.IP = net.ParseIP("192.168.10.101").To4()
-	lease, _ = s.reserveLease(p)
+	l2.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:bb")
-	lease.Expiry = time.Unix(4000000002, 0)
+	s.srv4.AddStaticLease(l2)
 
 	_ = os.Remove("leases.db")
 	s.dbStore()
-	s.reset()
+	s.srv4.ResetLeases(nil)
 
 	s.dbLoad()
-	check(t, bytes.Equal(s.leases[0].HWAddr, hw1), "leases[0].HWAddr")
-	check(t, bytes.Equal(s.leases[0].IP, []byte{1, 1, 1, 1}), "leases[0].IP")
-	check(t, s.leases[0].Expiry.Unix() == 4000000001, "leases[0].Expiry")
 
-	check(t, bytes.Equal(s.leases[1].HWAddr, hw2), "leases[1].HWAddr")
+	ll := s.srv4.GetLeases(LeasesAll)
-	check(t, bytes.Equal(s.leases[1].IP, []byte{1, 1, 1, 2}), "leases[1].IP")
+
-	check(t, s.leases[1].Expiry.Unix() == 4000000002, "leases[1].Expiry")
+	assert.Equal(t, "aa:aa:aa:aa:aa:bb", ll[0].HWAddr.String())
+	assert.Equal(t, "192.168.10.101", ll[0].IP.String())
+	assert.Equal(t, int64(leaseExpireStatic), ll[0].Expiry.Unix())
+
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ll[1].HWAddr.String())
+	assert.Equal(t, "192.168.10.100", ll[1].IP.String())
+	assert.Equal(t, exp1.Unix(), ll[1].Expiry.Unix())
 
 	_ = os.Remove("leases.db")
 }
 
 func TestIsValidSubnetMask(t *testing.T) {
-	if !isValidSubnetMask([]byte{255, 255, 255, 0}) {
+	assert.True(t, isValidSubnetMask([]byte{255, 255, 255, 0}))
-		t.Fatalf("isValidSubnetMask([]byte{255,255,255,0})")
+	assert.True(t, isValidSubnetMask([]byte{255, 255, 254, 0}))
-	}
+	assert.True(t, isValidSubnetMask([]byte{255, 255, 252, 0}))
-	if isValidSubnetMask([]byte{255, 255, 253, 0}) {
+	assert.True(t, !isValidSubnetMask([]byte{255, 255, 253, 0}))
-		t.Fatalf("isValidSubnetMask([]byte{255,255,253,0})")
+	assert.True(t, !isValidSubnetMask([]byte{255, 255, 255, 1}))
-	}
-	if isValidSubnetMask([]byte{0, 255, 255, 255}) {
-		t.Fatalf("isValidSubnetMask([]byte{255,255,253,0})")
-	}
 }
 
 func TestNormalizeLeases(t *testing.T) {

dhcpd/filter_conn.go

@@ -1,63 +0,0 @@
-package dhcpd
-
-import (
-	"net"
-
-	"github.com/joomcode/errorx"
-	"golang.org/x/net/ipv4"
-)
-
-// filterConn listens to 0.0.0.0:67, but accepts packets only from specific interface
-// This is necessary for DHCP daemon to work, since binding to IP address doesn't
-// us access to see Discover/Request packets from clients.
-//
-// TODO: on windows, controlmessage does not work, try to find out another way
-// https://github.com/golang/net/blob/master/ipv4/payload.go#L13
-type filterConn struct {
-	iface net.Interface
-	conn  *ipv4.PacketConn
-}
-
-func newFilterConn(iface net.Interface, address string) (*filterConn, error) {
-	c, err := net.ListenPacket("udp4", address)
-	if err != nil {
-		return nil, errorx.Decorate(err, "Couldn't listen to %s on UDP4", address)
-	}
-
-	p := ipv4.NewPacketConn(c)
-	err = p.SetControlMessage(ipv4.FlagInterface, true)
-	if err != nil {
-		c.Close()
-		return nil, errorx.Decorate(err, "Couldn't set control message FlagInterface on connection")
-	}
-
-	return &filterConn{iface: iface, conn: p}, nil
-}
-
-func (f *filterConn) ReadFrom(b []byte) (int, net.Addr, error) {
-	for { // read until we find a suitable packet
-		n, cm, addr, err := f.conn.ReadFrom(b)
-		if err != nil {
-			return 0, addr, errorx.Decorate(err, "Error when reading from socket")
-		}
-		if cm == nil {
-			// no controlmessage was passed, so pass the packet to the caller
-			return n, addr, nil
-		}
-		if cm.IfIndex == f.iface.Index {
-			return n, addr, nil
-		}
-		// packet doesn't match criteria, drop it
-	}
-}
-
-func (f *filterConn) WriteTo(b []byte, addr net.Addr) (int, error) {
-	cm := ipv4.ControlMessage{
-		IfIndex: f.iface.Index,
-	}
-	return f.conn.WriteTo(b, &cm, addr)
-}
-
-func (f *filterConn) Close() error {
-	return f.conn.Close()
-}

dhcpd/helpers.go

@@ -17,32 +17,24 @@ func isTimeout(err error) bool {
 	return operr.Timeout()
 }
 
-// return first IPv4 address of an interface, if there is any
+// Get IPv4 address list
-func getIfaceIPv4(iface *net.Interface) *net.IPNet {
+func getIfaceIPv4(iface net.Interface) []net.IP {
-	ifaceAddrs, err := iface.Addrs()
+	addrs, err := iface.Addrs()
 	if err != nil {
-		panic(err)
+		return nil
 	}
 
-	for _, addr := range ifaceAddrs {
+	var res []net.IP
-		ipnet, ok := addr.(*net.IPNet)
+	for _, a := range addrs {
+		ipnet, ok := a.(*net.IPNet)
 		if !ok {
-			// not an IPNet, should not happen
-			log.Fatalf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet", addr)
-		}
-
-		if ipnet.IP.To4() == nil {
-			log.Tracef("Got IP that is not IPv4: %v", ipnet.IP)
 			continue
 		}
-
+		if ipnet.IP.To4() != nil {
-		log.Tracef("Got IP that is IPv4: %v", ipnet.IP)
+			res = append(res, ipnet.IP.To4())
-		return &net.IPNet{
-			IP:   ipnet.IP.To4(),
-			Mask: ipnet.Mask,
 		}
 	}
-	return nil
+	return res
 }
 
 func wrapErrPrint(err error, message string, args ...interface{}) error {

dhcpd/network_utils_test.go

@@ -1,3 +1,5 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
 package dhcpd
 
 import (

dhcpd/server.go

@@ -0,0 +1,81 @@
+package dhcpd
+
+import (
+	"net"
+	"time"
+)
+
+// DHCPServer - DHCP server interface
+type DHCPServer interface {
+	// ResetLeases - reset leases
+	ResetLeases(leases []*Lease)
+	// GetLeases - get leases
+	GetLeases(flags int) []Lease
+	// GetLeasesRef - get reference to leases array
+	GetLeasesRef() []*Lease
+	// AddStaticLease - add a static lease
+	AddStaticLease(lease Lease) error
+	// RemoveStaticLease - remove a static lease
+	RemoveStaticLease(l Lease) error
+	// FindMACbyIP - find a MAC address by IP address in the currently active DHCP leases
+	FindMACbyIP(ip net.IP) net.HardwareAddr
+
+	// WriteDiskConfig4 - copy disk configuration
+	WriteDiskConfig4(c *V4ServerConf)
+	// WriteDiskConfig6 - copy disk configuration
+	WriteDiskConfig6(c *V6ServerConf)
+
+	// Start - start server
+	Start() error
+	// Stop - stop server
+	Stop()
+}
+
+// V4ServerConf - server configuration
+type V4ServerConf struct {
+	Enabled       bool   `yaml:"-"`
+	InterfaceName string `yaml:"-"`
+
+	GatewayIP  string `yaml:"gateway_ip"`
+	SubnetMask string `yaml:"subnet_mask"`
+
+	// The first & the last IP address for dynamic leases
+	// Bytes [0..2] of the last allowed IP address must match the first IP
+	RangeStart string `yaml:"range_start"`
+	RangeEnd   string `yaml:"range_end"`
+
+	LeaseDuration uint32 `yaml:"lease_duration"` // in seconds
+
+	// IP conflict detector: time (ms) to wait for ICMP reply
+	// 0: disable
+	ICMPTimeout uint32 `yaml:"icmp_timeout_msec"`
+
+	ipStart    net.IP        // starting IP address for dynamic leases
+	ipEnd      net.IP        // ending IP address for dynamic leases
+	leaseTime  time.Duration // the time during which a dynamic lease is considered valid
+	dnsIPAddrs []net.IP      // IPv4 addresses to return to DHCP clients as DNS server addresses
+	routerIP   net.IP        // value for Option Router
+	subnetMask net.IPMask    // value for Option SubnetMask
+
+	// Server calls this function when leases data changes
+	notify func(uint32)
+}
+
+// V6ServerConf - server configuration
+type V6ServerConf struct {
+	Enabled       bool   `yaml:"-"`
+	InterfaceName string `yaml:"-"`
+
+	// The first IP address for dynamic leases
+	// The last allowed IP address ends with 0xff byte
+	RangeStart string `yaml:"range_start"`
+
+	LeaseDuration uint32 `yaml:"lease_duration"` // in seconds
+
+	ipStart    net.IP        // starting IP address for dynamic leases
+	leaseTime  time.Duration // the time during which a dynamic lease is considered valid
+	dnsIPAddrs []net.IP      // IPv6 addresses to return to DHCP clients as DNS server addresses
+
+	// Server calls this function when leases data changes
+	notify func(uint32)
+}

dhcpd/standalone/main.go

@@ -1,115 +0,0 @@
-package main
-
-import (
-	"net"
-	"os"
-	"os/signal"
-	"syscall"
-	"time"
-
-	"github.com/AdguardTeam/AdGuardHome/dhcpd"
-	"github.com/AdguardTeam/golibs/log"
-	"github.com/krolaw/dhcp4"
-)
-
-func main() {
-	if len(os.Args) < 2 {
-		log.Printf("Usage: %s <interface name>", os.Args[0])
-		os.Exit(64)
-	}
-
-	ifaceName := os.Args[1]
-	present, err := dhcpd.CheckIfOtherDHCPServersPresent(ifaceName)
-	if err != nil {
-		panic(err)
-	}
-	log.Printf("Found DHCP server? %v", present)
-	if present {
-		log.Printf("Will not start DHCP server because there's already running one on the network")
-		os.Exit(1)
-	}
-
-	iface, err := net.InterfaceByName(ifaceName)
-	if err != nil {
-		panic(err)
-	}
-
-	// get ipv4 address of an interface
-	ifaceIPNet := getIfaceIPv4(iface)
-	if ifaceIPNet == nil {
-		panic(err)
-	}
-
-	// append 10 to server's IP address as start
-	start := dhcp4.IPAdd(ifaceIPNet.IP, 10)
-	// lease range is 100 IP's, but TODO: don't go beyond end of subnet mask
-	stop := dhcp4.IPAdd(start, 100)
-
-	server := dhcpd.Server{}
-	config := dhcpd.ServerConfig{
-		InterfaceName: ifaceName,
-		RangeStart:    start.String(),
-		RangeEnd:      stop.String(),
-		SubnetMask:    "255.255.255.0",
-		GatewayIP:     "192.168.7.1",
-	}
-	log.Printf("Starting DHCP server")
-	err = server.Init(config)
-	if err != nil {
-		panic(err)
-	}
-	err = server.Start()
-	if err != nil {
-		panic(err)
-	}
-
-	time.Sleep(time.Second)
-	log.Printf("Stopping DHCP server")
-	err = server.Stop()
-	if err != nil {
-		panic(err)
-	}
-	log.Printf("Starting DHCP server")
-	err = server.Start()
-	if err != nil {
-		panic(err)
-	}
-	log.Printf("Starting DHCP server while it's already running")
-	err = server.Start()
-	if err != nil {
-		panic(err)
-	}
-	log.Printf("Now serving DHCP")
-	signalChannel := make(chan os.Signal, 1)
-	signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM)
-	<-signalChannel
-
-}
-
-// return first IPv4 address of an interface, if there is any
-func getIfaceIPv4(iface *net.Interface) *net.IPNet {
-	ifaceAddrs, err := iface.Addrs()
-	if err != nil {
-		panic(err)
-	}
-
-	for _, addr := range ifaceAddrs {
-		ipnet, ok := addr.(*net.IPNet)
-		if !ok {
-			// not an IPNet, should not happen
-			log.Fatalf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet", addr)
-		}
-
-		if ipnet.IP.To4() == nil {
-			log.Printf("Got IP that is not IPv4: %v", ipnet.IP)
-			continue
-		}
-
-		log.Printf("Got IP that is IPv4: %v", ipnet.IP)
-		return &net.IPNet{
-			IP:   ipnet.IP.To4(),
-			Mask: ipnet.Mask,
-		}
-	}
-	return nil
-}

dhcpd/v4.go

@@ -0,0 +1,623 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package dhcpd
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/dhcpv4/server4"
+	"github.com/sparrc/go-ping"
+)
+
+// v4Server - DHCPv4 server
+type v4Server struct {
+	srv        *server4.Server
+	leasesLock sync.Mutex
+	leases     []*Lease
+	ipAddrs    [256]byte
+
+	conf V4ServerConf
+}
+
+// WriteDiskConfig4 - write configuration
+func (s *v4Server) WriteDiskConfig4(c *V4ServerConf) {
+	*c = s.conf
+}
+
+// WriteDiskConfig6 - write configuration
+func (s *v4Server) WriteDiskConfig6(c *V6ServerConf) {
+}
+
+// Return TRUE if IP address is within range [start..stop]
+func ip4InRange(start net.IP, stop net.IP, ip net.IP) bool {
+	if len(start) != 4 || len(stop) != 4 {
+		return false
+	}
+	from := binary.BigEndian.Uint32(start)
+	to := binary.BigEndian.Uint32(stop)
+	check := binary.BigEndian.Uint32(ip)
+	return from <= check && check <= to
+}
+
+// ResetLeases - reset leases
+func (s *v4Server) ResetLeases(leases []*Lease) {
+	s.leases = nil
+
+	for _, l := range leases {
+
+		if l.Expiry.Unix() != leaseExpireStatic &&
+			!ip4InRange(s.conf.ipStart, s.conf.ipEnd, l.IP) {
+
+			log.Debug("DHCPv4: skipping a lease with IP %v: not within current IP range", l.IP)
+			continue
+		}
+
+		s.addLease(l)
+	}
+}
+
+// GetLeasesRef - get leases
+func (s *v4Server) GetLeasesRef() []*Lease {
+	return s.leases
+}
+
+// Return TRUE if this lease holds a blacklisted IP
+func (s *v4Server) blacklisted(l *Lease) bool {
+	return l.HWAddr.String() == "00:00:00:00:00:00"
+}
+
+// GetLeases returns the list of current DHCP leases (thread-safe)
+func (s *v4Server) GetLeases(flags int) []Lease {
+	var result []Lease
+	now := time.Now().Unix()
+
+	s.leasesLock.Lock()
+	for _, lease := range s.leases {
+		if ((flags&LeasesDynamic) != 0 && lease.Expiry.Unix() > now && !s.blacklisted(lease)) ||
+			((flags&LeasesStatic) != 0 && lease.Expiry.Unix() == leaseExpireStatic) {
+			result = append(result, *lease)
+		}
+	}
+	s.leasesLock.Unlock()
+
+	return result
+}
+
+// FindMACbyIP - find a MAC address by IP address in the currently active DHCP leases
+func (s *v4Server) FindMACbyIP(ip net.IP) net.HardwareAddr {
+	now := time.Now().Unix()
+
+	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
+	ip4 := ip.To4()
+	if ip4 == nil {
+		return nil
+	}
+
+	for _, l := range s.leases {
+		if l.IP.Equal(ip4) {
+			unix := l.Expiry.Unix()
+			if unix > now || unix == leaseExpireStatic {
+				return l.HWAddr
+			}
+		}
+	}
+	return nil
+}
+
+// Add the specified IP to the black list for a time period
+func (s *v4Server) blacklistLease(lease *Lease) {
+	hw := make(net.HardwareAddr, 6)
+	lease.HWAddr = hw
+	lease.Hostname = ""
+	lease.Expiry = time.Now().Add(s.conf.leaseTime)
+}
+
+// Remove (swap) lease by index
+func (s *v4Server) leaseRemoveSwapByIndex(i int) {
+	s.ipAddrs[s.leases[i].IP[3]] = 0
+	log.Debug("DHCPv4: removed lease %s", s.leases[i].HWAddr)
+
+	n := len(s.leases)
+	if i != n-1 {
+		s.leases[i] = s.leases[n-1] // swap with the last element
+	}
+	s.leases = s.leases[:n-1]
+}
+
+// Remove a dynamic lease with the same properties
+// Return error if a static lease is found
+func (s *v4Server) rmDynamicLease(lease Lease) error {
+	for i := 0; i < len(s.leases); i++ {
+		l := s.leases[i]
+
+		if bytes.Equal(l.HWAddr, lease.HWAddr) {
+
+			if l.Expiry.Unix() == leaseExpireStatic {
+				return fmt.Errorf("static lease already exists")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+			l = s.leases[i]
+		}
+
+		if net.IP.Equal(l.IP, lease.IP) {
+
+			if l.Expiry.Unix() == leaseExpireStatic {
+				return fmt.Errorf("static lease already exists")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+		}
+	}
+	return nil
+}
+
+// Add a lease
+func (s *v4Server) addLease(l *Lease) {
+	s.leases = append(s.leases, l)
+	s.ipAddrs[l.IP[3]] = 1
+	log.Debug("DHCPv4: added lease %s <-> %s", l.IP, l.HWAddr)
+}
+
+// Remove a lease with the same properties
+func (s *v4Server) rmLease(lease Lease) error {
+	for i, l := range s.leases {
+		if net.IP.Equal(l.IP, lease.IP) {
+
+			if !bytes.Equal(l.HWAddr, lease.HWAddr) ||
+				l.Hostname != lease.Hostname {
+
+				return fmt.Errorf("Lease not found")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+			return nil
+		}
+	}
+	return fmt.Errorf("lease not found")
+}
+
+// AddStaticLease adds a static lease (thread-safe)
+func (s *v4Server) AddStaticLease(lease Lease) error {
+	if len(lease.IP) != 4 {
+		return fmt.Errorf("invalid IP")
+	}
+	if len(lease.HWAddr) != 6 {
+		return fmt.Errorf("invalid MAC")
+	}
+	lease.Expiry = time.Unix(leaseExpireStatic, 0)
+
+	s.leasesLock.Lock()
+	err := s.rmDynamicLease(lease)
+	if err != nil {
+		s.leasesLock.Unlock()
+		return err
+	}
+	s.addLease(&lease)
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+
+	s.conf.notify(LeaseChangedAddedStatic)
+	return nil
+}
+
+// RemoveStaticLease removes a static lease (thread-safe)
+func (s *v4Server) RemoveStaticLease(l Lease) error {
+	if len(l.IP) != 4 {
+		return fmt.Errorf("invalid IP")
+	}
+	if len(l.HWAddr) != 6 {
+		return fmt.Errorf("invalid MAC")
+	}
+
+	s.leasesLock.Lock()
+	err := s.rmLease(l)
+	if err != nil {
+		s.leasesLock.Unlock()
+		return err
+	}
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+
+	s.conf.notify(LeaseChangedRemovedStatic)
+	return nil
+}
+
+// Send ICMP to the specified machine
+// Return TRUE if it doesn't reply, which probably means that the IP is available
+func (s *v4Server) addrAvailable(target net.IP) bool {
+
+	if s.conf.ICMPTimeout == 0 {
+		return true
+	}
+
+	pinger, err := ping.NewPinger(target.String())
+	if err != nil {
+		log.Error("ping.NewPinger(): %v", err)
+		return true
+	}
+
+	pinger.SetPrivileged(true)
+	pinger.Timeout = time.Duration(s.conf.ICMPTimeout) * time.Millisecond
+	pinger.Count = 1
+	reply := false
+	pinger.OnRecv = func(pkt *ping.Packet) {
+		reply = true
+	}
+	log.Debug("DHCPv4: Sending ICMP Echo to %v", target)
+	pinger.Run()
+
+	if reply {
+		log.Info("DHCPv4: IP conflict: %v is already used by another device", target)
+		return false
+	}
+
+	log.Debug("DHCPv4: ICMP procedure is complete: %v", target)
+	return true
+}
+
+// Find lease by MAC
+func (s *v4Server) findLease(mac net.HardwareAddr) *Lease {
+	for i := range s.leases {
+		if bytes.Equal(mac, s.leases[i].HWAddr) {
+			return s.leases[i]
+		}
+	}
+	return nil
+}
+
+// Get next free IP
+func (s *v4Server) findFreeIP() net.IP {
+	for i := s.conf.ipStart[3]; ; i++ {
+		if s.ipAddrs[i] == 0 {
+			ip := make([]byte, 4)
+			copy(ip, s.conf.ipStart)
+			ip[3] = i
+			return ip
+		}
+		if i == s.conf.ipEnd[3] {
+			break
+		}
+	}
+	return nil
+}
+
+// Find an expired lease and return its index or -1
+func (s *v4Server) findExpiredLease() int {
+	now := time.Now().Unix()
+	for i, lease := range s.leases {
+		if lease.Expiry.Unix() != leaseExpireStatic &&
+			lease.Expiry.Unix() <= now {
+			return i
+		}
+	}
+	return -1
+}
+
+// Reserve lease for MAC
+func (s *v4Server) reserveLease(mac net.HardwareAddr) *Lease {
+	l := Lease{}
+	l.HWAddr = make([]byte, 6)
+	copy(l.HWAddr, mac)
+
+	l.IP = s.findFreeIP()
+	if l.IP == nil {
+		i := s.findExpiredLease()
+		if i < 0 {
+			return nil
+		}
+		copy(s.leases[i].HWAddr, mac)
+		return s.leases[i]
+	}
+
+	s.addLease(&l)
+	return &l
+}
+
+func (s *v4Server) commitLease(l *Lease) {
+	l.Expiry = time.Now().Add(s.conf.leaseTime)
+
+	s.leasesLock.Lock()
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+
+	s.conf.notify(LeaseChangedAdded)
+}
+
+// Process Discover request and return lease
+func (s *v4Server) processDiscover(req *dhcpv4.DHCPv4, resp *dhcpv4.DHCPv4) *Lease {
+	mac := req.ClientHWAddr
+
+	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
+	lease := s.findLease(mac)
+	if lease == nil {
+		toStore := false
+		for lease == nil {
+			lease = s.reserveLease(mac)
+			if lease == nil {
+				log.Debug("DHCPv4: No more IP addresses")
+				if toStore {
+					s.conf.notify(LeaseChangedDBStore)
+				}
+				return nil
+			}
+
+			toStore = true
+
+			if !s.addrAvailable(lease.IP) {
+				s.blacklistLease(lease)
+				lease = nil
+				continue
+			}
+			break
+		}
+
+		s.conf.notify(LeaseChangedDBStore)
+
+		// s.conf.notify(LeaseChangedBlacklisted)
+
+	} else {
+		reqIP := req.Options.Get(dhcpv4.OptionRequestedIPAddress)
+		if len(reqIP) != 0 &&
+			!bytes.Equal(reqIP, lease.IP) {
+			log.Debug("DHCPv4: different RequestedIP: %v != %v", reqIP, lease.IP)
+		}
+	}
+
+	hostname := req.Options.Get(dhcpv4.OptionHostName)
+	lease.Hostname = string(hostname)
+
+	resp.UpdateOption(dhcpv4.OptMessageType(dhcpv4.MessageTypeOffer))
+	return lease
+}
+
+// Process Request request and return lease
+// Return false if we don't need to reply
+func (s *v4Server) processRequest(req *dhcpv4.DHCPv4, resp *dhcpv4.DHCPv4) (*Lease, bool) {
+	var lease *Lease
+	mac := req.ClientHWAddr
+	hostname := req.Options.Get(dhcpv4.OptionHostName)
+	reqIP := req.Options.Get(dhcpv4.OptionRequestedIPAddress)
+	if reqIP == nil {
+		reqIP = req.ClientIPAddr
+	}
+
+	sid := req.Options.Get(dhcpv4.OptionServerIdentifier)
+	if len(sid) != 0 &&
+		!bytes.Equal(sid, s.conf.dnsIPAddrs[0]) {
+		log.Debug("DHCPv4: Bad OptionServerIdentifier in Request message for %s", mac)
+		return nil, false
+	}
+
+	if len(reqIP) != 4 {
+		log.Debug("DHCPv4: Bad OptionRequestedIPAddress in Request message for %s", mac)
+		return nil, false
+	}
+
+	s.leasesLock.Lock()
+	for _, l := range s.leases {
+		if bytes.Equal(l.HWAddr, mac) {
+			if !bytes.Equal(l.IP, reqIP) {
+				s.leasesLock.Unlock()
+				log.Debug("DHCPv4: Mismatched OptionRequestedIPAddress in Request message for %s", mac)
+				return nil, true
+			}
+
+			if !bytes.Equal([]byte(l.Hostname), hostname) {
+				s.leasesLock.Unlock()
+				log.Debug("DHCPv4: Mismatched OptionHostName in Request message for %s", mac)
+				return nil, true
+			}
+
+			lease = l
+			break
+		}
+	}
+	s.leasesLock.Unlock()
+
+	if lease == nil {
+		log.Debug("DHCPv4: No lease for %s", mac)
+		return nil, true
+	}
+
+	if lease.Expiry.Unix() != leaseExpireStatic {
+		s.commitLease(lease)
+	}
+
+	resp.UpdateOption(dhcpv4.OptMessageType(dhcpv4.MessageTypeAck))
+	return lease, true
+}
+
+// Find a lease associated with MAC and prepare response
+// Return 1: OK
+// Return 0: error; reply with Nak
+// Return -1: error; don't reply
+func (s *v4Server) process(req *dhcpv4.DHCPv4, resp *dhcpv4.DHCPv4) int {
+
+	var lease *Lease
+
+	resp.UpdateOption(dhcpv4.OptServerIdentifier(s.conf.dnsIPAddrs[0]))
+
+	switch req.MessageType() {
+
+	case dhcpv4.MessageTypeDiscover:
+		lease = s.processDiscover(req, resp)
+		if lease == nil {
+			return 0
+		}
+
+	case dhcpv4.MessageTypeRequest:
+		var toReply bool
+		lease, toReply = s.processRequest(req, resp)
+		if lease == nil {
+			if toReply {
+				return 0
+			}
+			return -1 // drop packet
+		}
+	}
+
+	resp.YourIPAddr = make([]byte, 4)
+	copy(resp.YourIPAddr, lease.IP)
+
+	resp.UpdateOption(dhcpv4.OptIPAddressLeaseTime(s.conf.leaseTime))
+	resp.UpdateOption(dhcpv4.OptRouter(s.conf.routerIP))
+	resp.UpdateOption(dhcpv4.OptSubnetMask(s.conf.subnetMask))
+	resp.UpdateOption(dhcpv4.OptDNS(s.conf.dnsIPAddrs...))
+	return 1
+}
+
+// client(0.0.0.0:68) -> (Request:ClientMAC,Type=Discover,ClientID,ReqIP,HostName) -> server(255.255.255.255:67)
+// client(255.255.255.255:68) <- (Reply:YourIP,ClientMAC,Type=Offer,ServerID,SubnetMask,LeaseTime) <- server(<IP>:67)
+// client(0.0.0.0:68) -> (Request:ClientMAC,Type=Request,ClientID,ReqIP||ClientIP,HostName,ServerID,ParamReqList) -> server(255.255.255.255:67)
+// client(255.255.255.255:68) <- (Reply:YourIP,ClientMAC,Type=ACK,ServerID,SubnetMask,LeaseTime) <- server(<IP>:67)
+func (s *v4Server) packetHandler(conn net.PacketConn, peer net.Addr, req *dhcpv4.DHCPv4) {
+	log.Debug("DHCPv4: received message: %s", req.Summary())
+
+	switch req.MessageType() {
+	case dhcpv4.MessageTypeDiscover,
+		dhcpv4.MessageTypeRequest:
+		//
+
+	default:
+		log.Debug("DHCPv4: unsupported message type %d", req.MessageType())
+		return
+	}
+
+	resp, err := dhcpv4.NewReplyFromRequest(req)
+	if err != nil {
+		log.Debug("DHCPv4: dhcpv4.New: %s", err)
+		return
+	}
+
+	if len(req.ClientHWAddr) != 6 {
+		log.Debug("DHCPv4: Invalid ClientHWAddr")
+		return
+	}
+
+	r := s.process(req, resp)
+	if r < 0 {
+		return
+	} else if r == 0 {
+		resp.Options.Update(dhcpv4.OptMessageType(dhcpv4.MessageTypeNak))
+	}
+
+	log.Debug("DHCPv4: sending: %s", resp.Summary())
+
+	_, err = conn.WriteTo(resp.ToBytes(), peer)
+	if err != nil {
+		log.Error("DHCPv4: conn.Write to %s failed: %s", peer, err)
+		return
+	}
+}
+
+// Start - start server
+func (s *v4Server) Start() error {
+	if !s.conf.Enabled {
+		return nil
+	}
+
+	iface, err := net.InterfaceByName(s.conf.InterfaceName)
+	if err != nil {
+		return fmt.Errorf("DHCPv4: Couldn't find interface by name %s: %s", s.conf.InterfaceName, err)
+	}
+
+	log.Debug("DHCPv4: starting...")
+	s.conf.dnsIPAddrs = getIfaceIPv4(*iface)
+	if len(s.conf.dnsIPAddrs) == 0 {
+		log.Debug("DHCPv4: no IPv6 address for interface %s", iface.Name)
+		return nil
+	}
+
+	laddr := &net.UDPAddr{
+		IP:   net.ParseIP("0.0.0.0"),
+		Port: dhcpv4.ServerPort,
+	}
+	s.srv, err = server4.NewServer(iface.Name, laddr, s.packetHandler, server4.WithDebugLogger())
+	if err != nil {
+		return err
+	}
+
+	log.Info("DHCPv4: listening")
+
+	go func() {
+		err = s.srv.Serve()
+		log.Debug("DHCPv4: srv.Serve: %s", err)
+	}()
+	return nil
+}
+
+// Stop - stop server
+func (s *v4Server) Stop() {
+	if s.srv == nil {
+		return
+	}
+
+	log.Debug("DHCPv4: stopping")
+	err := s.srv.Close()
+	if err != nil {
+		log.Error("DHCPv4: srv.Close: %s", err)
+	}
+	// now s.srv.Serve() will return
+	s.srv = nil
+}
+
+// Create DHCPv4 server
+func v4Create(conf V4ServerConf) (DHCPServer, error) {
+	s := &v4Server{}
+	s.conf = conf
+
+	if !conf.Enabled {
+		return s, nil
+	}
+
+	var err error
+	s.conf.routerIP, err = parseIPv4(s.conf.GatewayIP)
+	if err != nil {
+		return s, fmt.Errorf("DHCPv4: %s", err)
+	}
+
+	subnet, err := parseIPv4(s.conf.SubnetMask)
+	if err != nil || !isValidSubnetMask(subnet) {
+		return s, fmt.Errorf("DHCPv4: invalid subnet mask: %s", s.conf.SubnetMask)
+	}
+	s.conf.subnetMask = make([]byte, 4)
+	copy(s.conf.subnetMask, subnet)
+
+	s.conf.ipStart, err = parseIPv4(conf.RangeStart)
+	if s.conf.ipStart == nil {
+		return s, fmt.Errorf("DHCPv4: %s", err)
+	}
+	if s.conf.ipStart[0] == 0 {
+		return s, fmt.Errorf("DHCPv4: invalid range start IP")
+	}
+
+	s.conf.ipEnd, err = parseIPv4(conf.RangeEnd)
+	if s.conf.ipEnd == nil {
+		return s, fmt.Errorf("DHCPv4: %s", err)
+	}
+	if !net.IP.Equal(s.conf.ipStart[:3], s.conf.ipEnd[:3]) ||
+		s.conf.ipStart[3] > s.conf.ipEnd[3] {
+		return s, fmt.Errorf("DHCPv4: range end IP should match range start IP")
+	}
+
+	if conf.LeaseDuration == 0 {
+		s.conf.leaseTime = time.Hour * 24
+		s.conf.LeaseDuration = uint32(s.conf.leaseTime.Seconds())
+	} else {
+		s.conf.leaseTime = time.Second * time.Duration(conf.LeaseDuration)
+	}
+
+	return s, nil
+}

dhcpd/v46_windows.go

@@ -0,0 +1,47 @@
+package dhcpd
+
+// 'u-root/u-root' package, a dependency of 'insomniacslk/dhcp' package, doesn't build on Windows
+
+import "net"
+
+type winServer struct {
+}
+
+func (s *winServer) ResetLeases(leases []*Lease) {
+}
+func (s *winServer) GetLeases(flags int) []Lease {
+	return nil
+}
+func (s *winServer) GetLeasesRef() []*Lease {
+	return nil
+}
+func (s *winServer) AddStaticLease(lease Lease) error {
+	return nil
+}
+func (s *winServer) RemoveStaticLease(l Lease) error {
+	return nil
+}
+func (s *winServer) FindMACbyIP(ip net.IP) net.HardwareAddr {
+	return nil
+}
+
+func (s *winServer) WriteDiskConfig4(c *V4ServerConf) {
+}
+func (s *winServer) WriteDiskConfig6(c *V6ServerConf) {
+}
+
+func (s *winServer) Start() error {
+	return nil
+}
+func (s *winServer) Stop() {
+}
+func (s *winServer) Reset() {
+}
+
+func v4Create(conf V4ServerConf) (DHCPServer, error) {
+	return &winServer{}, nil
+}
+
+func v6Create(conf V6ServerConf) (DHCPServer, error) {
+	return &winServer{}, nil
+}

dhcpd/v4_test.go

@@ -0,0 +1,232 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package dhcpd
+
+import (
+	"net"
+	"testing"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/stretchr/testify/assert"
+)
+
+func notify4(flags uint32) {
+}
+
+func TestV4StaticLeaseAddRemove(t *testing.T) {
+	conf := V4ServerConf{
+		Enabled:    true,
+		RangeStart: "192.168.10.100",
+		RangeEnd:   "192.168.10.200",
+		GatewayIP:  "192.168.10.1",
+		SubnetMask: "255.255.255.0",
+		notify:     notify4,
+	}
+	s, err := v4Create(conf)
+	assert.True(t, err == nil)
+
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 0, len(ls))
+
+	// add static lease
+	l := Lease{}
+	l.IP = net.ParseIP("192.168.10.150").To4()
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// try to add the same static lease - fail
+	assert.True(t, s.AddStaticLease(l) != nil)
+
+	// check
+	ls = s.GetLeases(LeasesStatic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "192.168.10.150", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+	assert.True(t, ls[0].Expiry.Unix() == leaseExpireStatic)
+
+	// try to remove static lease - fail
+	l.IP = net.ParseIP("192.168.10.110").To4()
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.RemoveStaticLease(l) != nil)
+
+	// remove static lease
+	l.IP = net.ParseIP("192.168.10.150").To4()
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.RemoveStaticLease(l) == nil)
+
+	// check
+	ls = s.GetLeases(LeasesStatic)
+	assert.Equal(t, 0, len(ls))
+}
+
+func TestV4StaticLeaseAddReplaceDynamic(t *testing.T) {
+	conf := V4ServerConf{
+		Enabled:    true,
+		RangeStart: "192.168.10.100",
+		RangeEnd:   "192.168.10.200",
+		GatewayIP:  "192.168.10.1",
+		SubnetMask: "255.255.255.0",
+		notify:     notify4,
+	}
+	sIface, err := v4Create(conf)
+	s := sIface.(*v4Server)
+	assert.True(t, err == nil)
+
+	// add dynamic lease
+	ld := Lease{}
+	ld.IP = net.ParseIP("192.168.10.150").To4()
+	ld.HWAddr, _ = net.ParseMAC("11:aa:aa:aa:aa:aa")
+	s.addLease(&ld)
+
+	// add dynamic lease
+	{
+		ld := Lease{}
+		ld.IP = net.ParseIP("192.168.10.151").To4()
+		ld.HWAddr, _ = net.ParseMAC("22:aa:aa:aa:aa:aa")
+		s.addLease(&ld)
+	}
+
+	// add static lease with the same IP
+	l := Lease{}
+	l.IP = net.ParseIP("192.168.10.150").To4()
+	l.HWAddr, _ = net.ParseMAC("33:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// add static lease with the same MAC
+	l = Lease{}
+	l.IP = net.ParseIP("192.168.10.152").To4()
+	l.HWAddr, _ = net.ParseMAC("22:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// check
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 2, len(ls))
+
+	assert.Equal(t, "192.168.10.150", ls[0].IP.String())
+	assert.Equal(t, "33:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+	assert.True(t, ls[0].Expiry.Unix() == leaseExpireStatic)
+
+	assert.Equal(t, "192.168.10.152", ls[1].IP.String())
+	assert.Equal(t, "22:aa:aa:aa:aa:aa", ls[1].HWAddr.String())
+	assert.True(t, ls[1].Expiry.Unix() == leaseExpireStatic)
+}
+
+func TestV4StaticLeaseGet(t *testing.T) {
+	conf := V4ServerConf{
+		Enabled:    true,
+		RangeStart: "192.168.10.100",
+		RangeEnd:   "192.168.10.200",
+		GatewayIP:  "192.168.10.1",
+		SubnetMask: "255.255.255.0",
+		notify:     notify4,
+	}
+	sIface, err := v4Create(conf)
+	s := sIface.(*v4Server)
+	assert.True(t, err == nil)
+	s.conf.dnsIPAddrs = []net.IP{net.ParseIP("192.168.10.1").To4()}
+
+	l := Lease{}
+	l.IP = net.ParseIP("192.168.10.150").To4()
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// "Discover"
+	mac, _ := net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	req, _ := dhcpv4.NewDiscovery(mac)
+	resp, _ := dhcpv4.NewReplyFromRequest(req)
+	assert.Equal(t, 1, s.process(req, resp))
+
+	// check "Offer"
+	assert.Equal(t, dhcpv4.MessageTypeOffer, resp.MessageType())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", resp.ClientHWAddr.String())
+	assert.Equal(t, "192.168.10.150", resp.YourIPAddr.String())
+	assert.Equal(t, "192.168.10.1", resp.Router()[0].String())
+	assert.Equal(t, "192.168.10.1", resp.ServerIdentifier().String())
+	assert.Equal(t, "255.255.255.0", net.IP(resp.SubnetMask()).String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
+
+	// "Request"
+	req, _ = dhcpv4.NewRequestFromOffer(resp)
+	resp, _ = dhcpv4.NewReplyFromRequest(req)
+	assert.Equal(t, 1, s.process(req, resp))
+
+	// check "Ack"
+	assert.Equal(t, dhcpv4.MessageTypeAck, resp.MessageType())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", resp.ClientHWAddr.String())
+	assert.Equal(t, "192.168.10.150", resp.YourIPAddr.String())
+	assert.Equal(t, "192.168.10.1", resp.Router()[0].String())
+	assert.Equal(t, "192.168.10.1", resp.ServerIdentifier().String())
+	assert.Equal(t, "255.255.255.0", net.IP(resp.SubnetMask()).String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
+
+	dnsAddrs := resp.DNS()
+	assert.Equal(t, 1, len(dnsAddrs))
+	assert.Equal(t, "192.168.10.1", dnsAddrs[0].String())
+
+	// check lease
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "192.168.10.150", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+}
+
+func TestV4DynamicLeaseGet(t *testing.T) {
+	conf := V4ServerConf{
+		Enabled:    true,
+		RangeStart: "192.168.10.100",
+		RangeEnd:   "192.168.10.200",
+		GatewayIP:  "192.168.10.1",
+		SubnetMask: "255.255.255.0",
+		notify:     notify4,
+	}
+	sIface, err := v4Create(conf)
+	s := sIface.(*v4Server)
+	assert.True(t, err == nil)
+	s.conf.dnsIPAddrs = []net.IP{net.ParseIP("192.168.10.1").To4()}
+
+	// "Discover"
+	mac, _ := net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	req, _ := dhcpv4.NewDiscovery(mac)
+	resp, _ := dhcpv4.NewReplyFromRequest(req)
+	assert.Equal(t, 1, s.process(req, resp))
+
+	// check "Offer"
+	assert.Equal(t, dhcpv4.MessageTypeOffer, resp.MessageType())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", resp.ClientHWAddr.String())
+	assert.Equal(t, "192.168.10.100", resp.YourIPAddr.String())
+	assert.Equal(t, "192.168.10.1", resp.Router()[0].String())
+	assert.Equal(t, "192.168.10.1", resp.ServerIdentifier().String())
+	assert.Equal(t, "255.255.255.0", net.IP(resp.SubnetMask()).String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
+
+	// "Request"
+	req, _ = dhcpv4.NewRequestFromOffer(resp)
+	resp, _ = dhcpv4.NewReplyFromRequest(req)
+	assert.Equal(t, 1, s.process(req, resp))
+
+	// check "Ack"
+	assert.Equal(t, dhcpv4.MessageTypeAck, resp.MessageType())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", resp.ClientHWAddr.String())
+	assert.Equal(t, "192.168.10.100", resp.YourIPAddr.String())
+	assert.Equal(t, "192.168.10.1", resp.Router()[0].String())
+	assert.Equal(t, "192.168.10.1", resp.ServerIdentifier().String())
+	assert.Equal(t, "255.255.255.0", net.IP(resp.SubnetMask()).String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), resp.IPAddressLeaseTime(-1).Seconds())
+
+	dnsAddrs := resp.DNS()
+	assert.Equal(t, 1, len(dnsAddrs))
+	assert.Equal(t, "192.168.10.1", dnsAddrs[0].String())
+
+	// check lease
+	ls := s.GetLeases(LeasesDynamic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "192.168.10.100", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+
+	start := net.ParseIP("192.168.10.100").To4()
+	stop := net.ParseIP("192.168.10.200").To4()
+	assert.True(t, !ip4InRange(start, stop, net.ParseIP("192.168.10.99").To4()))
+	assert.True(t, !ip4InRange(start, stop, net.ParseIP("192.168.11.100").To4()))
+	assert.True(t, !ip4InRange(start, stop, net.ParseIP("192.168.11.201").To4()))
+	assert.True(t, ip4InRange(start, stop, net.ParseIP("192.168.10.100").To4()))
+}

dhcpd/v6.go

@@ -0,0 +1,638 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package dhcpd
+
+import (
+	"bytes"
+	"fmt"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/insomniacslk/dhcp/dhcpv6"
+	"github.com/insomniacslk/dhcp/dhcpv6/server6"
+	"github.com/insomniacslk/dhcp/iana"
+)
+
+const valueIAID = "ADGH" // value for IANA.ID
+
+// v6Server - DHCPv6 server
+type v6Server struct {
+	srv        *server6.Server
+	leasesLock sync.Mutex
+	leases     []*Lease
+	ipAddrs    [256]byte
+	sid        dhcpv6.Duid
+
+	conf V6ServerConf
+}
+
+// WriteDiskConfig4 - write configuration
+func (s *v6Server) WriteDiskConfig4(c *V4ServerConf) {
+}
+
+// WriteDiskConfig6 - write configuration
+func (s *v6Server) WriteDiskConfig6(c *V6ServerConf) {
+	*c = s.conf
+}
+
+// Return TRUE if IP address is within range [start..0xff]
+// nolint(staticcheck)
+func ip6InRange(start net.IP, ip net.IP) bool {
+	if len(start) != 16 {
+		return false
+	}
+	if !bytes.Equal(start[:15], ip[:15]) {
+		return false
+	}
+	return start[15] <= ip[15]
+}
+
+// ResetLeases - reset leases
+func (s *v6Server) ResetLeases(ll []*Lease) {
+	s.leases = nil
+	for _, l := range ll {
+
+		if l.Expiry.Unix() != leaseExpireStatic &&
+			!ip6InRange(s.conf.ipStart, l.IP) {
+
+			log.Debug("DHCPv6: skipping a lease with IP %v: not within current IP range", l.IP)
+			continue
+		}
+
+		s.addLease(l)
+	}
+}
+
+// GetLeases - get current leases
+func (s *v6Server) GetLeases(flags int) []Lease {
+	var result []Lease
+	s.leasesLock.Lock()
+	for _, lease := range s.leases {
+
+		if lease.Expiry.Unix() == leaseExpireStatic {
+			if (flags & LeasesStatic) != 0 {
+				result = append(result, *lease)
+			}
+
+		} else {
+			if (flags & LeasesDynamic) != 0 {
+				result = append(result, *lease)
+			}
+		}
+	}
+	s.leasesLock.Unlock()
+	return result
+}
+
+// GetLeasesRef - get leases
+func (s *v6Server) GetLeasesRef() []*Lease {
+	return s.leases
+}
+
+// FindMACbyIP - find a MAC address by IP address in the currently active DHCP leases
+func (s *v6Server) FindMACbyIP(ip net.IP) net.HardwareAddr {
+	now := time.Now().Unix()
+
+	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
+	for _, l := range s.leases {
+		if l.IP.Equal(ip) {
+			unix := l.Expiry.Unix()
+			if unix > now || unix == leaseExpireStatic {
+				return l.HWAddr
+			}
+		}
+	}
+	return nil
+}
+
+// Remove (swap) lease by index
+func (s *v6Server) leaseRemoveSwapByIndex(i int) {
+	s.ipAddrs[s.leases[i].IP[15]] = 0
+	log.Debug("DHCPv6: removed lease %s", s.leases[i].HWAddr)
+
+	n := len(s.leases)
+	if i != n-1 {
+		s.leases[i] = s.leases[n-1] // swap with the last element
+	}
+	s.leases = s.leases[:n-1]
+}
+
+// Remove a dynamic lease with the same properties
+// Return error if a static lease is found
+func (s *v6Server) rmDynamicLease(lease Lease) error {
+	for i := 0; i < len(s.leases); i++ {
+		l := s.leases[i]
+
+		if bytes.Equal(l.HWAddr, lease.HWAddr) {
+
+			if l.Expiry.Unix() == leaseExpireStatic {
+				return fmt.Errorf("static lease already exists")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+			l = s.leases[i]
+		}
+
+		if net.IP.Equal(l.IP, lease.IP) {
+
+			if l.Expiry.Unix() == leaseExpireStatic {
+				return fmt.Errorf("static lease already exists")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+		}
+	}
+	return nil
+}
+
+// AddStaticLease - add a static lease
+func (s *v6Server) AddStaticLease(l Lease) error {
+	if len(l.IP) != 16 {
+		return fmt.Errorf("invalid IP")
+	}
+	if len(l.HWAddr) != 6 {
+		return fmt.Errorf("invalid MAC")
+	}
+
+	l.Expiry = time.Unix(leaseExpireStatic, 0)
+
+	s.leasesLock.Lock()
+	err := s.rmDynamicLease(l)
+	if err != nil {
+		s.leasesLock.Unlock()
+		return err
+	}
+	s.addLease(&l)
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+
+	s.conf.notify(LeaseChangedAddedStatic)
+	return nil
+}
+
+// RemoveStaticLease - remove a static lease
+func (s *v6Server) RemoveStaticLease(l Lease) error {
+	if len(l.IP) != 16 {
+		return fmt.Errorf("invalid IP")
+	}
+	if len(l.HWAddr) != 6 {
+		return fmt.Errorf("invalid MAC")
+	}
+
+	s.leasesLock.Lock()
+	err := s.rmLease(l)
+	if err != nil {
+		s.leasesLock.Unlock()
+		return err
+	}
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+	s.conf.notify(LeaseChangedRemovedStatic)
+	return nil
+}
+
+// Add a lease
+func (s *v6Server) addLease(l *Lease) {
+	s.leases = append(s.leases, l)
+	s.ipAddrs[l.IP[15]] = 1
+	log.Debug("DHCPv6: added lease %s <-> %s", l.IP, l.HWAddr)
+}
+
+// Remove a lease with the same properties
+func (s *v6Server) rmLease(lease Lease) error {
+	for i, l := range s.leases {
+		if net.IP.Equal(l.IP, lease.IP) {
+
+			if !bytes.Equal(l.HWAddr, lease.HWAddr) ||
+				l.Hostname != lease.Hostname {
+
+				return fmt.Errorf("Lease not found")
+			}
+
+			s.leaseRemoveSwapByIndex(i)
+			return nil
+		}
+	}
+	return fmt.Errorf("lease not found")
+}
+
+// Find lease by MAC
+func (s *v6Server) findLease(mac net.HardwareAddr) *Lease {
+	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
+	for i := range s.leases {
+		if bytes.Equal(mac, s.leases[i].HWAddr) {
+			return s.leases[i]
+		}
+	}
+	return nil
+}
+
+// Find an expired lease and return its index or -1
+func (s *v6Server) findExpiredLease() int {
+	now := time.Now().Unix()
+	for i, lease := range s.leases {
+		if lease.Expiry.Unix() != leaseExpireStatic &&
+			lease.Expiry.Unix() <= now {
+			return i
+		}
+	}
+	return -1
+}
+
+// Get next free IP
+func (s *v6Server) findFreeIP() net.IP {
+	for i := s.conf.ipStart[15]; ; i++ {
+		if s.ipAddrs[i] == 0 {
+			ip := make([]byte, 16)
+			copy(ip, s.conf.ipStart)
+			ip[15] = i
+			return ip
+		}
+		if i == 0xff {
+			break
+		}
+	}
+	return nil
+}
+
+// Reserve lease for MAC
+func (s *v6Server) reserveLease(mac net.HardwareAddr) *Lease {
+	l := Lease{}
+	l.HWAddr = make([]byte, 6)
+	copy(l.HWAddr, mac)
+
+	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
+	copy(l.IP, s.conf.ipStart)
+	l.IP = s.findFreeIP()
+	if l.IP == nil {
+		i := s.findExpiredLease()
+		if i < 0 {
+			return nil
+		}
+		copy(s.leases[i].HWAddr, mac)
+		return s.leases[i]
+	}
+
+	s.addLease(&l)
+	return &l
+}
+
+func (s *v6Server) commitDynamicLease(l *Lease) {
+	l.Expiry = time.Now().Add(s.conf.leaseTime)
+
+	s.leasesLock.Lock()
+	s.conf.notify(LeaseChangedDBStore)
+	s.leasesLock.Unlock()
+	s.conf.notify(LeaseChangedAdded)
+}
+
+// Check Client ID
+func (s *v6Server) checkCID(msg *dhcpv6.Message) error {
+	if msg.Options.ClientID() == nil {
+		return fmt.Errorf("DHCPv6: no ClientID option in request")
+	}
+	return nil
+}
+
+// Check ServerID policy
+func (s *v6Server) checkSID(msg *dhcpv6.Message) error {
+	sid := msg.Options.ServerID()
+
+	switch msg.Type() {
+	case dhcpv6.MessageTypeSolicit,
+		dhcpv6.MessageTypeConfirm,
+		dhcpv6.MessageTypeRebind:
+
+		if sid != nil {
+			return fmt.Errorf("DHCPv6: drop packet: ServerID option in message %s", msg.Type().String())
+		}
+
+	case dhcpv6.MessageTypeRequest,
+		dhcpv6.MessageTypeRenew,
+		dhcpv6.MessageTypeRelease,
+		dhcpv6.MessageTypeDecline:
+
+		if sid == nil {
+			return fmt.Errorf("DHCPv6: drop packet: no ServerID option in message %s", msg.Type().String())
+		}
+		if !sid.Equal(s.sid) {
+			return fmt.Errorf("DHCPv6: drop packet: mismatched ServerID option in message %s: %s",
+				msg.Type().String(), sid.String())
+		}
+	}
+
+	return nil
+}
+
+// . IAAddress must be equal to the lease's IP
+func (s *v6Server) checkIA(msg *dhcpv6.Message, lease *Lease) error {
+	switch msg.Type() {
+	case dhcpv6.MessageTypeRequest,
+		dhcpv6.MessageTypeConfirm,
+		dhcpv6.MessageTypeRenew,
+		dhcpv6.MessageTypeRebind:
+
+		oia := msg.Options.OneIANA()
+		if oia == nil {
+			return fmt.Errorf("no IANA option in %s", msg.Type().String())
+		}
+
+		oiaAddr := oia.Options.OneAddress()
+		if oiaAddr == nil {
+			return fmt.Errorf("no IANA.Addr option in %s", msg.Type().String())
+		}
+
+		if !oiaAddr.IPv6Addr.Equal(lease.IP) {
+			return fmt.Errorf("invalid IANA.Addr option in %s", msg.Type().String())
+		}
+	}
+	return nil
+}
+
+// Store lease in DB (if necessary) and return lease life time
+func (s *v6Server) commitLease(msg *dhcpv6.Message, lease *Lease) time.Duration {
+	lifetime := s.conf.leaseTime
+
+	switch msg.Type() {
+	case dhcpv6.MessageTypeSolicit:
+		//
+
+	case dhcpv6.MessageTypeConfirm:
+		lifetime = lease.Expiry.Sub(time.Now())
+
+	case dhcpv6.MessageTypeRequest,
+		dhcpv6.MessageTypeRenew,
+		dhcpv6.MessageTypeRebind:
+
+		if lease.Expiry.Unix() != leaseExpireStatic {
+			s.commitDynamicLease(lease)
+		}
+	}
+	return lifetime
+}
+
+// Find a lease associated with MAC and prepare response
+func (s *v6Server) process(msg *dhcpv6.Message, req dhcpv6.DHCPv6, resp dhcpv6.DHCPv6) bool {
+	switch msg.Type() {
+	case dhcpv6.MessageTypeSolicit,
+		dhcpv6.MessageTypeRequest,
+		dhcpv6.MessageTypeConfirm,
+		dhcpv6.MessageTypeRenew,
+		dhcpv6.MessageTypeRebind:
+		// continue
+
+	default:
+		return false
+	}
+
+	mac, err := dhcpv6.ExtractMAC(req)
+	if err != nil {
+		log.Debug("DHCPv6: dhcpv6.ExtractMAC: %s", err)
+		return false
+	}
+
+	lease := s.findLease(mac)
+	if lease == nil {
+		log.Debug("DHCPv6: no lease for: %s", mac)
+
+		switch msg.Type() {
+
+		case dhcpv6.MessageTypeSolicit:
+			lease = s.reserveLease(mac)
+			if lease == nil {
+				return false
+			}
+
+		default:
+			return false
+		}
+	}
+
+	err = s.checkIA(msg, lease)
+	if err != nil {
+		log.Debug("DHCPv6: %s", err)
+		return false
+	}
+
+	lifetime := s.commitLease(msg, lease)
+
+	oia := &dhcpv6.OptIANA{
+		T1: lifetime / 2,
+		T2: time.Duration(float32(lifetime) / 1.5),
+	}
+	roia := msg.Options.OneIANA()
+	if roia != nil {
+		copy(oia.IaId[:], roia.IaId[:])
+	} else {
+		copy(oia.IaId[:], []byte(valueIAID))
+	}
+	oiaAddr := &dhcpv6.OptIAAddress{
+		IPv6Addr:          lease.IP,
+		PreferredLifetime: lifetime,
+		ValidLifetime:     lifetime,
+	}
+	oia.Options = dhcpv6.IdentityOptions{
+		Options: []dhcpv6.Option{oiaAddr},
+	}
+	resp.AddOption(oia)
+
+	if msg.IsOptionRequested(dhcpv6.OptionDNSRecursiveNameServer) {
+		resp.UpdateOption(dhcpv6.OptDNS(s.conf.dnsIPAddrs...))
+	}
+
+	fqdn := msg.GetOneOption(dhcpv6.OptionFQDN)
+	if fqdn != nil {
+		resp.AddOption(fqdn)
+	}
+
+	resp.AddOption(&dhcpv6.OptStatusCode{
+		StatusCode:    iana.StatusSuccess,
+		StatusMessage: "success",
+	})
+	return true
+}
+
+// 1.
+// fe80::* (client) --(Solicit + ClientID+IANA())-> ff02::1:2
+// server -(Advertise + ClientID+ServerID+IANA(IAAddress)> fe80::*
+// fe80::* --(Request + ClientID+ServerID+IANA(IAAddress))-> ff02::1:2
+// server -(Reply + ClientID+ServerID+IANA(IAAddress)+DNS)> fe80::*
+//
+// 2.
+// fe80::* --(Confirm|Renew|Rebind + ClientID+IANA(IAAddress))-> ff02::1:2
+// server -(Reply + ClientID+ServerID+IANA(IAAddress)+DNS)> fe80::*
+//
+// 3.
+// fe80::* --(Release + ClientID+ServerID+IANA(IAAddress))-> ff02::1:2
+func (s *v6Server) packetHandler(conn net.PacketConn, peer net.Addr, req dhcpv6.DHCPv6) {
+	msg, err := req.GetInnerMessage()
+	if err != nil {
+		log.Error("DHCPv6: %s", err)
+		return
+	}
+
+	log.Debug("DHCPv6: received: %s", req.Summary())
+
+	err = s.checkCID(msg)
+	if err != nil {
+		log.Debug("%s", err)
+		return
+	}
+
+	err = s.checkSID(msg)
+	if err != nil {
+		log.Debug("%s", err)
+		return
+	}
+
+	var resp dhcpv6.DHCPv6
+
+	switch msg.Type() {
+	case dhcpv6.MessageTypeSolicit:
+		if msg.GetOneOption(dhcpv6.OptionRapidCommit) == nil {
+			resp, err = dhcpv6.NewAdvertiseFromSolicit(msg)
+			break
+		}
+		fallthrough
+
+	case dhcpv6.MessageTypeRequest,
+		dhcpv6.MessageTypeConfirm,
+		dhcpv6.MessageTypeRenew,
+		dhcpv6.MessageTypeRebind,
+		dhcpv6.MessageTypeRelease,
+		dhcpv6.MessageTypeInformationRequest:
+		resp, err = dhcpv6.NewReplyFromMessage(msg)
+
+	default:
+		log.Error("DHCPv6: message type %d not supported", msg.Type())
+		return
+	}
+
+	if err != nil {
+		log.Error("DHCPv6: %s", err)
+		return
+	}
+
+	resp.AddOption(dhcpv6.OptServerID(s.sid))
+
+	_ = s.process(msg, req, resp)
+
+	log.Debug("DHCPv6: sending: %s", resp.Summary())
+
+	_, err = conn.WriteTo(resp.ToBytes(), peer)
+	if err != nil {
+		log.Error("DHCPv6: conn.Write to %s failed: %s", peer, err)
+		return
+	}
+}
+
+// Get IPv6 address list
+func getIfaceIPv6(iface net.Interface) []net.IP {
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return nil
+	}
+
+	var res []net.IP
+	for _, a := range addrs {
+		ipnet, ok := a.(*net.IPNet)
+		if !ok {
+			continue
+		}
+		if ipnet.IP.To4() == nil {
+			res = append(res, ipnet.IP)
+		}
+	}
+	return res
+}
+
+// Start - start server
+func (s *v6Server) Start() error {
+	if !s.conf.Enabled {
+		return nil
+	}
+
+	iface, err := net.InterfaceByName(s.conf.InterfaceName)
+	if err != nil {
+		return wrapErrPrint(err, "Couldn't find interface by name %s", s.conf.InterfaceName)
+	}
+
+	log.Debug("DHCPv6: starting...")
+	s.conf.dnsIPAddrs = getIfaceIPv6(*iface)
+	if len(s.conf.dnsIPAddrs) == 0 {
+		log.Debug("DHCPv6: no IPv6 address for interface %s", iface.Name)
+		return nil
+	}
+
+	if len(iface.HardwareAddr) != 6 {
+		return fmt.Errorf("DHCPv6: invalid MAC %s", iface.HardwareAddr)
+	}
+	s.sid = dhcpv6.Duid{
+		Type:          dhcpv6.DUID_LLT,
+		HwType:        iana.HWTypeEthernet,
+		LinkLayerAddr: iface.HardwareAddr,
+		Time:          dhcpv6.GetTime(),
+	}
+
+	laddr := &net.UDPAddr{
+		IP:   net.ParseIP("::"),
+		Port: dhcpv6.DefaultServerPort,
+	}
+	s.srv, err = server6.NewServer(iface.Name, laddr, s.packetHandler, server6.WithDebugLogger())
+	if err != nil {
+		return err
+	}
+
+	go func() {
+		err = s.srv.Serve()
+		log.Debug("DHCPv6: srv.Serve: %s", err)
+	}()
+	return nil
+}
+
+// Stop - stop server
+func (s *v6Server) Stop() {
+	if s.srv == nil {
+		return
+	}
+
+	log.Debug("DHCPv6: stopping")
+	err := s.srv.Close()
+	if err != nil {
+		log.Error("DHCPv6: srv.Close: %s", err)
+	}
+	// now server.Serve() will return
+	s.srv = nil
+}
+
+// Create DHCPv6 server
+func v6Create(conf V6ServerConf) (DHCPServer, error) {
+	s := &v6Server{}
+	s.conf = conf
+
+	if !conf.Enabled {
+		return s, nil
+	}
+
+	s.conf.ipStart = net.ParseIP(conf.RangeStart)
+	if s.conf.ipStart == nil {
+		return s, fmt.Errorf("DHCPv6: invalid range-start IP: %s", conf.RangeStart)
+	}
+
+	if conf.LeaseDuration == 0 {
+		s.conf.leaseTime = time.Hour * 24
+		s.conf.LeaseDuration = uint32(s.conf.leaseTime.Seconds())
+	} else {
+		s.conf.leaseTime = time.Second * time.Duration(conf.LeaseDuration)
+	}
+
+	return s, nil
+}

dhcpd/v6_test.go

@@ -0,0 +1,225 @@
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package dhcpd
+
+import (
+	"net"
+	"testing"
+
+	"github.com/insomniacslk/dhcp/dhcpv6"
+	"github.com/insomniacslk/dhcp/iana"
+	"github.com/stretchr/testify/assert"
+)
+
+func notify6(flags uint32) {
+}
+
+func TestV6StaticLeaseAddRemove(t *testing.T) {
+	conf := V6ServerConf{
+		Enabled:    true,
+		RangeStart: "2001::1",
+		notify:     notify6,
+	}
+	s, err := v6Create(conf)
+	assert.True(t, err == nil)
+
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 0, len(ls))
+
+	// add static lease
+	l := Lease{}
+	l.IP = net.ParseIP("2001::1")
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// try to add static lease - fail
+	assert.True(t, s.AddStaticLease(l) != nil)
+
+	// check
+	ls = s.GetLeases(LeasesStatic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "2001::1", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+	assert.True(t, ls[0].Expiry.Unix() == leaseExpireStatic)
+
+	// try to remove static lease - fail
+	l.IP = net.ParseIP("2001::2")
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.RemoveStaticLease(l) != nil)
+
+	// remove static lease
+	l.IP = net.ParseIP("2001::1")
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.RemoveStaticLease(l) == nil)
+
+	// check
+	ls = s.GetLeases(LeasesStatic)
+	assert.Equal(t, 0, len(ls))
+}
+
+func TestV6StaticLeaseAddReplaceDynamic(t *testing.T) {
+	conf := V6ServerConf{
+		Enabled:    true,
+		RangeStart: "2001::1",
+		notify:     notify6,
+	}
+	sIface, err := v6Create(conf)
+	s := sIface.(*v6Server)
+	assert.True(t, err == nil)
+
+	// add dynamic lease
+	ld := Lease{}
+	ld.IP = net.ParseIP("2001::1")
+	ld.HWAddr, _ = net.ParseMAC("11:aa:aa:aa:aa:aa")
+	s.addLease(&ld)
+
+	// add dynamic lease
+	{
+		ld := Lease{}
+		ld.IP = net.ParseIP("2001::2")
+		ld.HWAddr, _ = net.ParseMAC("22:aa:aa:aa:aa:aa")
+		s.addLease(&ld)
+	}
+
+	// add static lease with the same IP
+	l := Lease{}
+	l.IP = net.ParseIP("2001::1")
+	l.HWAddr, _ = net.ParseMAC("33:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// add static lease with the same MAC
+	l = Lease{}
+	l.IP = net.ParseIP("2001::3")
+	l.HWAddr, _ = net.ParseMAC("22:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// check
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 2, len(ls))
+
+	assert.Equal(t, "2001::1", ls[0].IP.String())
+	assert.Equal(t, "33:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+	assert.True(t, ls[0].Expiry.Unix() == leaseExpireStatic)
+
+	assert.Equal(t, "2001::3", ls[1].IP.String())
+	assert.Equal(t, "22:aa:aa:aa:aa:aa", ls[1].HWAddr.String())
+	assert.True(t, ls[1].Expiry.Unix() == leaseExpireStatic)
+}
+
+func TestV6GetLease(t *testing.T) {
+	conf := V6ServerConf{
+		Enabled:    true,
+		RangeStart: "2001::1",
+		notify:     notify6,
+	}
+	sIface, err := v6Create(conf)
+	s := sIface.(*v6Server)
+	assert.True(t, err == nil)
+	s.conf.dnsIPAddrs = []net.IP{net.ParseIP("2000::1")}
+	s.sid = dhcpv6.Duid{
+		Type:   dhcpv6.DUID_LLT,
+		HwType: iana.HWTypeEthernet,
+	}
+	s.sid.LinkLayerAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+
+	l := Lease{}
+	l.IP = net.ParseIP("2001::1")
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	assert.True(t, s.AddStaticLease(l) == nil)
+
+	// "Solicit"
+	mac, _ := net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	req, _ := dhcpv6.NewSolicit(mac)
+	msg, _ := req.GetInnerMessage()
+	resp, _ := dhcpv6.NewAdvertiseFromSolicit(msg)
+	assert.True(t, s.process(msg, req, resp))
+	resp.AddOption(dhcpv6.OptServerID(s.sid))
+
+	// check "Advertise"
+	assert.Equal(t, dhcpv6.MessageTypeAdvertise, resp.Type())
+	oia := resp.Options.OneIANA()
+	oiaAddr := oia.Options.OneAddress()
+	assert.Equal(t, "2001::1", oiaAddr.IPv6Addr.String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), oiaAddr.ValidLifetime.Seconds())
+
+	// "Request"
+	req, _ = dhcpv6.NewRequestFromAdvertise(resp)
+	msg, _ = req.GetInnerMessage()
+	resp, _ = dhcpv6.NewReplyFromMessage(msg)
+	assert.True(t, s.process(msg, req, resp))
+
+	// check "Reply"
+	assert.Equal(t, dhcpv6.MessageTypeReply, resp.Type())
+	oia = resp.Options.OneIANA()
+	oiaAddr = oia.Options.OneAddress()
+	assert.Equal(t, "2001::1", oiaAddr.IPv6Addr.String())
+	assert.Equal(t, s.conf.leaseTime.Seconds(), oiaAddr.ValidLifetime.Seconds())
+
+	dnsAddrs := resp.Options.DNS()
+	assert.Equal(t, 1, len(dnsAddrs))
+	assert.Equal(t, "2000::1", dnsAddrs[0].String())
+
+	// check lease
+	ls := s.GetLeases(LeasesStatic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "2001::1", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+}
+
+func TestV6GetDynamicLease(t *testing.T) {
+	conf := V6ServerConf{
+		Enabled:    true,
+		RangeStart: "2001::2",
+		notify:     notify6,
+	}
+	sIface, err := v6Create(conf)
+	s := sIface.(*v6Server)
+	assert.True(t, err == nil)
+	s.conf.dnsIPAddrs = []net.IP{net.ParseIP("2000::1")}
+	s.sid = dhcpv6.Duid{
+		Type:   dhcpv6.DUID_LLT,
+		HwType: iana.HWTypeEthernet,
+	}
+	s.sid.LinkLayerAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+
+	// "Solicit"
+	mac, _ := net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	req, _ := dhcpv6.NewSolicit(mac)
+	msg, _ := req.GetInnerMessage()
+	resp, _ := dhcpv6.NewAdvertiseFromSolicit(msg)
+	assert.True(t, s.process(msg, req, resp))
+	resp.AddOption(dhcpv6.OptServerID(s.sid))
+
+	// check "Advertise"
+	assert.Equal(t, dhcpv6.MessageTypeAdvertise, resp.Type())
+	oia := resp.Options.OneIANA()
+	oiaAddr := oia.Options.OneAddress()
+	assert.Equal(t, "2001::2", oiaAddr.IPv6Addr.String())
+
+	// "Request"
+	req, _ = dhcpv6.NewRequestFromAdvertise(resp)
+	msg, _ = req.GetInnerMessage()
+	resp, _ = dhcpv6.NewReplyFromMessage(msg)
+	assert.True(t, s.process(msg, req, resp))
+
+	// check "Reply"
+	assert.Equal(t, dhcpv6.MessageTypeReply, resp.Type())
+	oia = resp.Options.OneIANA()
+	oiaAddr = oia.Options.OneAddress()
+	assert.Equal(t, "2001::2", oiaAddr.IPv6Addr.String())
+
+	dnsAddrs := resp.Options.DNS()
+	assert.Equal(t, 1, len(dnsAddrs))
+	assert.Equal(t, "2000::1", dnsAddrs[0].String())
+
+	// check lease
+	ls := s.GetLeases(LeasesDynamic)
+	assert.Equal(t, 1, len(ls))
+	assert.Equal(t, "2001::2", ls[0].IP.String())
+	assert.Equal(t, "aa:aa:aa:aa:aa:aa", ls[0].HWAddr.String())
+
+	assert.True(t, !ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2001::1")))
+	assert.True(t, !ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2002::2")))
+	assert.True(t, ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2001::2")))
+	assert.True(t, ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2001::3")))
+}

dnsforward/dnsforward.go

@@ -44,10 +44,10 @@ var webRegistered bool
 //
 // The zero Server is empty and ready for use.
 type Server struct {
-	dnsProxy   *proxy.Proxy         // DNS proxy instance
+	dnsProxy   *proxy.Proxy          // DNS proxy instance
-	dnsFilter  *dnsfilter.Dnsfilter // DNS filter instance
+	dnsFilter  *dnsfilter.Dnsfilter  // DNS filter instance
-	dhcpServer *dhcpd.Server        // DHCP server instance (optional)
+	dhcpServer dhcpd.ServerInterface // DHCP server instance (optional)
-	queryLog   querylog.QueryLog    // Query log instance
+	queryLog   querylog.QueryLog     // Query log instance
 	stats      stats.Stats
 	access     *accessCtx
 
@@ -72,7 +72,7 @@ type DNSCreateParams struct {
 	DNSFilter  *dnsfilter.Dnsfilter
 	Stats      stats.Stats
 	QueryLog   querylog.QueryLog
-	DHCPServer *dhcpd.Server
+	DHCPServer dhcpd.ServerInterface
 }
 
 // NewServer creates a new instance of the dnsforward.Server

dnsforward/dnsforward_test.go

@@ -1018,9 +1018,22 @@ func TestMatchDNSName(t *testing.T) {
 	assert.True(t, !matchDNSName(dnsNames, "*.host2"))
 }
 
+type testDHCP struct {
+}
+
+func (d *testDHCP) Leases(flags int) []dhcpd.Lease {
+	l := dhcpd.Lease{}
+	l.IP = net.ParseIP("127.0.0.1").To4()
+	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
+	l.Hostname = "localhost"
+	return []dhcpd.Lease{l}
+}
+func (d *testDHCP) SetOnLeaseChanged(onLeaseChanged dhcpd.OnLeaseChangedT) {
+	return
+}
+
 func TestPTRResponse(t *testing.T) {
-	dhcp := &dhcpd.Server{}
+	dhcp := &testDHCP{}
-	dhcp.IPpool = make(map[[4]byte]net.HardwareAddr)
 
 	c := dnsfilter.Config{}
 	f := dnsfilter.New(&c, nil)
@@ -1033,12 +1046,6 @@ func TestPTRResponse(t *testing.T) {
 	assert.True(t, err == nil)
 	assert.Nil(t, s.Start())
 
-	l := dhcpd.Lease{}
-	l.IP = net.ParseIP("127.0.0.1").To4()
-	l.HWAddr, _ = net.ParseMAC("aa:aa:aa:aa:aa:aa")
-	l.Hostname = "localhost"
-	dhcp.AddStaticLease(l)
-
 	addr := s.dnsProxy.Addr(proxy.ProtoUDP)
 	req := createTestMessage("1.0.0.127.in-addr.arpa.")
 	req.Question[0].Qtype = dns.TypePTR

go.mod

@@ -9,13 +9,17 @@ require (
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/fsnotify/fsnotify v1.4.7
 	github.com/gobuffalo/packr v1.30.1
+	github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 // indirect
+	github.com/insomniacslk/dhcp v0.0.0-20200420235442-ed3125c2efe7
 	github.com/joomcode/errorx v1.0.1
 	github.com/kardianos/service v1.1.0
-	github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414
+	github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 // indirect
+	github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065 // indirect
 	github.com/miekg/dns v1.1.29
 	github.com/pkg/errors v0.9.1
 	github.com/sparrc/go-ping v0.0.0-20190613174326-4e5b6552494c
 	github.com/stretchr/testify v1.5.1
+	github.com/u-root/u-root v6.0.0+incompatible // indirect
 	go.etcd.io/bbolt v1.3.4
 	golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8
 	golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e

go.sum

@@ -49,9 +49,18 @@ github.com/gobuffalo/packr v1.30.1 h1:hu1fuVR3fXEZR7rXNW3h8rqSML8EVAf6KNm0NKO/wK
 github.com/gobuffalo/packr v1.30.1/go.mod h1:ljMyFO2EcrnzsHsN99cvbq055Y9OhRrIaviy289eRuk=
 github.com/gobuffalo/packr/v2 v2.5.1 h1:TFOeY2VoGamPjQLiNDT3mn//ytzk236VMO2j7iHxJR4=
 github.com/gobuffalo/packr/v2 v2.5.1/go.mod h1:8f9c96ITobJlPzI44jj+4tHnEKNt0xXWSVlXRN9X1Iw=
+github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
+github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
+github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
+github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 h1:/jC7qQFrv8CrSJVmaolDVOxTfS9kc36uB6H40kdbQq8=
+github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
 github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
+github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
+github.com/insomniacslk/dhcp v0.0.0-20200420235442-ed3125c2efe7 h1:iaCm+9nZdYb8XCSU2TfIb0qYTcAlIv2XzyKR2d2xZ38=
+github.com/insomniacslk/dhcp v0.0.0-20200420235442-ed3125c2efe7/go.mod h1:CfMdguCK66I5DAUJgGKyNz8aB6vO5dZzkm9Xep6WGvw=
+github.com/jessevdk/go-flags v1.4.0 h1:4IU2WS7AumrZ/40jfhf4QVDMsQwqA7VEHozFRrGARJA=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/joho/godotenv v1.3.0 h1:Zjp+RcGpHhGlrMbJzXTrZZPrWj+1vfm90La1wgB6Bhc=
 github.com/joho/godotenv v1.3.0/go.mod h1:7hK45KPybAkOC6peb+G5yklZfMxEjkZhHbwpqxOKXbg=
@@ -69,9 +78,12 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414 h1:6wnYc2S/lVM7BvR32BM74ph7bPgqMztWopMYKgVyEho=
-github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414/go.mod h1:0AqAH3ZogsCrvrtUpvc6EtVKbc3w6xwZhkvGLuqyi3o=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
+github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 h1:lez6TS6aAau+8wXUP3G9I3TGlmPFEq2CTxBaRqY6AGE=
+github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7/go.mod h1:U6ZQobyTjI/tJyq2HG+i/dfSoFUt8/aZCM+GKtmFk/Y=
+github.com/mdlayher/raw v0.0.0-20190606142536-fef19f00fc18/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
+github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065 h1:aFkJ6lx4FPip+S+Uw4aTegFMct9shDvP+79PsSxpm3w=
+github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
 github.com/miekg/dns v1.1.29 h1:xHBEhR+t5RzcFJjBLJlax2daXOrTYtr9z4WdKEfWFzg=
 github.com/miekg/dns v1.1.29/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
@@ -104,11 +116,14 @@ github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/u-root/u-root v6.0.0+incompatible h1:YqPGmRoRyYmeg17KIWFRSyVq6LX5T6GSzawyA6wG6EE=
+github.com/u-root/u-root v6.0.0+incompatible/go.mod h1:RYkpo8pTHrNjW08opNd/U6p/RJE7K0D8fXO0d47+3YY=
 github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
 go.etcd.io/bbolt v1.3.4 h1:hi1bXHMVrlQh6WwxAy+qZCV/SYIlqo+Ushwdpa4tAKg=
@@ -123,6 +138,9 @@ golang.org/x/crypto v0.0.0-20200403201458-baeed622b8d8/go.mod h1:LzIPMQfyMNhhGPh
 golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190419010253-1f3472d942ba/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859 h1:R/3boaszxrf1GEUWTVDzSKVwLmSJpwZ1yqXm8j0v2QI=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e h1:3G+cUijn7XD+S4eJFddp53Pv7+slrESplyjG25HgL+k=
@@ -134,8 +152,10 @@ golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190204203706-41f3e6584952/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 v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190418153312-f0ce4c0180be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190515120540-06a5c4944438/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190606122018-79a91cf218c4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

home/clients.go

@@ -86,6 +86,7 @@ type clientsContainer struct {
 }
 
 // Init initializes clients container
+// dhcpServer: optional
 // Note: this function must be called only once
 func (clients *clientsContainer) Init(objects []clientObject, dhcpServer *dhcpd.Server, autoHosts *util.AutoHosts) {
 	if clients.list != nil {
@@ -106,7 +107,9 @@ func (clients *clientsContainer) Init(objects []clientObject, dhcpServer *dhcpd.
 
 	if !clients.testing {
 		clients.addFromDHCP()
-		clients.dhcpServer.SetOnLeaseChanged(clients.onDHCPLeaseChanged)
+		if clients.dhcpServer != nil {
+			clients.dhcpServer.SetOnLeaseChanged(clients.onDHCPLeaseChanged)
+		}
 		clients.autoHosts.SetOnChanged(clients.onHostsChanged)
 	}
 }

home/config.go

@@ -127,10 +127,6 @@ var config = configuration{
 		PortHTTPS:      443,
 		PortDNSOverTLS: 853, // needs to be passed through to dnsproxy
 	},
-	DHCP: dhcpd.ServerConfig{
-		LeaseDuration: 86400,
-		ICMPTimeout:   1000,
-	},
 	logSettings: logSettings{
 		LogCompress:   false,
 		LogLocalTime:  false,
@@ -156,6 +152,10 @@ func initConfig() {
 	config.DNS.DnsfilterConf.ParentalCacheSize = 1 * 1024 * 1024
 	config.DNS.DnsfilterConf.CacheTime = 30
 	config.Filters = defaultFilters()
+
+	config.DHCP.Conf4.LeaseDuration = 86400
+	config.DHCP.Conf4.ICMPTimeout = 1000
+	config.DHCP.Conf6.LeaseDuration = 86400
 }
 
 // getConfigFilename returns path to the current config file

home/control.go

@@ -56,6 +56,7 @@ func handleStatus(w http.ResponseWriter, r *http.Request) {
 
 		"protection_enabled": c.ProtectionEnabled,
 	}
+	data["dhcp_available"] = (Context.dhcpServer != nil)
 
 	jsonVal, err := json.Marshal(data)
 	if err != nil {

home/dhcp.go

@@ -1,36 +0,0 @@
-package home
-
-import (
-	"github.com/joomcode/errorx"
-)
-
-func startDHCPServer() error {
-	if !config.DHCP.Enabled {
-		// not enabled, don't do anything
-		return nil
-	}
-
-	err := Context.dhcpServer.Init(config.DHCP)
-	if err != nil {
-		return errorx.Decorate(err, "Couldn't init DHCP server")
-	}
-
-	err = Context.dhcpServer.Start()
-	if err != nil {
-		return errorx.Decorate(err, "Couldn't start DHCP server")
-	}
-	return nil
-}
-
-func stopDHCPServer() error {
-	if !config.DHCP.Enabled {
-		return nil
-	}
-
-	err := Context.dhcpServer.Stop()
-	if err != nil {
-		return errorx.Decorate(err, "Couldn't stop DHCP server")
-	}
-
-	return nil
-}

home/home.go

@@ -219,10 +219,8 @@ func run(args options) {
 	config.DHCP.WorkDir = Context.workDir
 	config.DHCP.HTTPRegister = httpRegister
 	config.DHCP.ConfigModified = onConfigModified
-	Context.dhcpServer = dhcpd.Create(config.DHCP)
+	if runtime.GOOS != "windows" {
-	if Context.dhcpServer == nil {
+		Context.dhcpServer = dhcpd.Create(config.DHCP)
-		log.Error("Failed to initialize DHCP server, exiting")
-		os.Exit(1)
 	}
 	Context.autoHosts.Init("")
 
@@ -317,9 +315,8 @@ func run(args options) {
 			}
 		}()
 
-		err = startDHCPServer()
+		if Context.dhcpServer != nil {
-		if err != nil {
+			_ = Context.dhcpServer.Start()
-			log.Fatal(err)
 		}
 	}
 
@@ -505,9 +502,9 @@ func cleanup() {
 	if err != nil {
 		log.Error("Couldn't stop DNS server: %s", err)
 	}
-	err = stopDHCPServer()
+
-	if err != nil {
+	if Context.dhcpServer != nil {
-		log.Error("Couldn't stop DHCP server: %s", err)
+		Context.dhcpServer.Stop()
 	}
 
 	Context.autoHosts.Close()

openapi/openapi.yaml

@@ -348,8 +348,6 @@ paths:
                     application/json:
                         schema:
                             $ref: "#/components/schemas/DhcpConfig"
-                description: DHCP configuration JSON
-                required: true
             responses:
                 "200":
                     description: OK
@@ -965,6 +963,8 @@ components:
                     maximum: 65535
                 protection_enabled:
                     type: boolean
+                dhcp_available:
+                    type: boolean
                 querylog_enabled:
                     type: boolean
                 running:
@@ -999,6 +999,8 @@ components:
                         - tls://1.0.0.1
                 protection_enabled:
                     type: boolean
+                dhcp_available:
+                    type: boolean
                 ratelimit:
                     type: integer
                 blocking_mode:
@@ -1259,17 +1261,18 @@ components:
                     description: Time period to keep data (1 | 7 | 30 | 90)
         DhcpConfig:
             type: object
-            description: Built-in DHCP server configuration
-            required:
-                - enabled
-                - gateway_ip
-                - subnet_mask
-                - range_start
-                - range_end
-                - lease_duration
             properties:
                 enabled:
                     type: boolean
+                interface_name:
+                    type: string
+                v4:
+                    $ref: "#/components/schemas/DhcpConfigV4"
+                v6:
+                    $ref: "#/components/schemas/DhcpConfigV6"
+        DhcpConfigV4:
+            type: object
+            properties:
                 gateway_ip:
                     type: string
                     example: 192.168.1.1
@@ -1283,8 +1286,14 @@ components:
                     type: string
                     example: 192.168.10.50
                 lease_duration:
+                    type: integer
+        DhcpConfigV6:
+            type: object
+            properties:
+                range_start:
                     type: string
-                    example: 12h
+                lease_duration:
+                    type: integer
         DhcpLease:
             type: object
             description: DHCP lease information
@@ -1305,8 +1314,7 @@ components:
                     example: dell
                 expires:
                     type: string
-                    format: date-time
+                    example: "2017-07-21T17:32:28Z"
-                    example: 2017-07-21T17:32:28Z
         DhcpStaticLease:
             type: object
             description: DHCP static lease information
@@ -1332,8 +1340,14 @@ components:
                 - config
                 - leases
             properties:
-                config:
+                enabled:
-                    $ref: "#/components/schemas/DhcpConfig"
+                    type: boolean
+                interface_name:
+                    type: string
+                v4:
+                    $ref: "#/components/schemas/DhcpConfigV4"
+                v6:
+                    $ref: "#/components/schemas/DhcpConfigV6"
                 leases:
                     type: array
                     items: