Pull request 2070: 4923 gopacket DHCP vol.4

Merge in DNS/adguard-home from 4923-gopacket-dhcp-vol.4 to master

Updates #4923.

Squashed commit of the following:

commit 4b87258c70ac98b2abb1ac95f7e916e244b3cd08
Merge: 61458864f 9b91a8740
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Nov 16 14:05:34 2023 +0300

    Merge branch 'master' into 4923-gopacket-dhcp-vol.4

commit 61458864f3df7a027e65060a5f0fb516cc7911a7
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Nov 15 18:48:40 2023 +0300

    all: imp code

commit 506a0ab81e76beebb900f86580577563b471e4e2
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 14 15:59:56 2023 +0300

    all: cleanup moving lease

commit 8d218b732662ac4308ed09d28c1bf9f65906d47c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Nov 13 18:13:39 2023 +0300

    all: rm old leases type

internal/dhcpd/config.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/errors"
 )
 
@@ -49,16 +50,16 @@ type ServerConfig struct {
 // DHCPServer - DHCP server interface
 type DHCPServer interface {
 	// ResetLeases resets leases.
-	ResetLeases(leases []*Lease) (err error)
+	ResetLeases(leases []*dhcpsvc.Lease) (err error)
 	// GetLeases returns deep clones of the current leases.
-	GetLeases(flags GetLeasesFlags) (leases []*Lease)
+	GetLeases(flags GetLeasesFlags) (leases []*dhcpsvc.Lease)
 	// AddStaticLease - add a static lease
-	AddStaticLease(l *Lease) (err error)
+	AddStaticLease(l *dhcpsvc.Lease) (err error)
 	// RemoveStaticLease - remove a static lease
-	RemoveStaticLease(l *Lease) (err error)
+	RemoveStaticLease(l *dhcpsvc.Lease) (err error)
 
 	// UpdateStaticLease updates IP, hostname of the lease.
-	UpdateStaticLease(l *Lease) (err error)
+	UpdateStaticLease(l *dhcpsvc.Lease) (err error)
 
 	// FindMACbyIP returns a MAC address by the IP address of its lease, if
 	// there is one.
@@ -81,7 +82,7 @@ type DHCPServer interface {
 	Start() (err error)
 	// Stop - stop server
 	Stop() (err error)
-	getLeasesRef() []*Lease
+	getLeasesRef() []*dhcpsvc.Lease
 }
 
 // V4ServerConf - server configuration

internal/dhcpd/db.go

@@ -5,9 +5,13 @@ package dhcpd
 import (
 	"encoding/json"
 	"fmt"
+	"net"
+	"net/netip"
 	"os"
 	"strings"
+	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/errors"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/google/renameio/v2/maybe"
@@ -28,7 +32,60 @@ type dataLeases struct {
 	Version int `json:"version"`
 
 	// Leases is the list containing stored DHCP leases.
-	Leases []*Lease `json:"leases"`
+	Leases []*dbLease `json:"leases"`
+}
+
+// dbLease is the structure of stored lease.
+type dbLease struct {
+	Expiry   string     `json:"expires"`
+	IP       netip.Addr `json:"ip"`
+	Hostname string     `json:"hostname"`
+	HWAddr   string     `json:"mac"`
+	IsStatic bool       `json:"static"`
+}
+
+// fromLease converts *dhcpsvc.Lease to *dbLease.
+func fromLease(l *dhcpsvc.Lease) (dl *dbLease) {
+	var expiryStr string
+	if !l.IsStatic {
+		// The front-end is waiting for RFC 3999 format of the time value.  It
+		// also shouldn't got an Expiry field for static leases.
+		//
+		// See https://github.com/AdguardTeam/AdGuardHome/issues/2692.
+		expiryStr = l.Expiry.Format(time.RFC3339)
+	}
+
+	return &dbLease{
+		Expiry:   expiryStr,
+		Hostname: l.Hostname,
+		HWAddr:   l.HWAddr.String(),
+		IP:       l.IP,
+		IsStatic: l.IsStatic,
+	}
+}
+
+// toLease converts *dbLease to *dhcpsvc.Lease.
+func (dl *dbLease) toLease() (l *dhcpsvc.Lease, err error) {
+	mac, err := net.ParseMAC(dl.HWAddr)
+	if err != nil {
+		return nil, fmt.Errorf("parsing hardware address: %w", err)
+	}
+
+	expiry := time.Time{}
+	if !dl.IsStatic {
+		expiry, err = time.Parse(time.RFC3339, dl.Expiry)
+		if err != nil {
+			return nil, fmt.Errorf("parsing expiry time: %w", err)
+		}
+	}
+
+	return &dhcpsvc.Lease{
+		Expiry:   expiry,
+		IP:       dl.IP,
+		Hostname: dl.Hostname,
+		HWAddr:   mac,
+		IsStatic: dl.IsStatic,
+	}, nil
 }
 
 // dbLoad loads stored leases.
@@ -49,15 +106,22 @@ func (s *server) dbLoad() (err error) {
 	}
 
 	leases := dl.Leases
-
+	leases4 := []*dhcpsvc.Lease{}
-	leases4 := []*Lease{}
+	leases6 := []*dhcpsvc.Lease{}
-	leases6 := []*Lease{}
 
 	for _, l := range leases {
-		if l.IP.Is4() {
+		var lease *dhcpsvc.Lease
-			leases4 = append(leases4, l)
+		lease, err = l.toLease()
+		if err != nil {
+			log.Info("dhcp: invalid lease: %s", err)
+
+			continue
+		}
+
+		if lease.IP.Is4() {
+			leases4 = append(leases4, lease)
 		} else {
-			leases6 = append(leases6, l)
+			leases6 = append(leases6, lease)
 		}
 	}
 
@@ -73,8 +137,12 @@ func (s *server) dbLoad() (err error) {
 		}
 	}
 
-	log.Info("dhcp: loaded leases v4:%d  v6:%d  total-read:%d from DB",
+	log.Info(
-		len(leases4), len(leases6), len(leases))
+		"dhcp: loaded leases v4:%d  v6:%d  total-read:%d from DB",
+		len(leases4),
+		len(leases6),
+		len(leases),
+	)
 
 	return nil
 }
@@ -83,24 +151,26 @@ func (s *server) dbLoad() (err error) {
 func (s *server) dbStore() (err error) {
 	// Use an empty slice here as opposed to nil so that it doesn't write
 	// "null" into the database file if leases are empty.
-	leases := []*Lease{}
+	leases := []*dbLease{}
 
-	leases4 := s.srv4.getLeasesRef()
+	for _, l := range s.srv4.getLeasesRef() {
-	leases = append(leases, leases4...)
+		leases = append(leases, fromLease(l))
+	}
 
 	if s.srv6 != nil {
-		leases6 := s.srv6.getLeasesRef()
+		for _, l := range s.srv6.getLeasesRef() {
-		leases = append(leases, leases6...)
+			leases = append(leases, fromLease(l))
+		}
 	}
 
 	return writeDB(s.conf.dbFilePath, leases)
 }
 
 // writeDB writes leases to file at path.
-func writeDB(path string, leases []*Lease) (err error) {
+func writeDB(path string, leases []*dbLease) (err error) {
 	defer func() { err = errors.Annotate(err, "writing db: %w") }()
 
-	slices.SortFunc(leases, func(a, b *Lease) (res int) {
+	slices.SortFunc(leases, func(a, b *dbLease) (res int) {
 		return strings.Compare(a.Hostname, b.Hostname)
 	})
 

internal/dhcpd/dhcpd.go

@@ -2,7 +2,6 @@
 package dhcpd
 
 import (
-	"encoding/json"
 	"fmt"
 	"net"
 	"net/netip"
@@ -12,7 +11,6 @@ import (
 	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/timeutil"
-	"golang.org/x/exp/slices"
 )
 
 const (
@@ -29,105 +27,6 @@ const (
 	defaultBackoff     time.Duration = 500 * time.Millisecond
 )
 
-// Lease contains the necessary information about a DHCP lease.  It's used as is
-// in the database, so don't change it until it's absolutely necessary, see
-// [dataVersion].
-//
-// TODO(e.burkov):  Unexport it and use [dhcpsvc.Lease].
-type Lease struct {
-	// Expiry is the expiration time of the lease.
-	Expiry time.Time `json:"expires"`
-
-	// Hostname of the client.
-	Hostname string `json:"hostname"`
-
-	// HWAddr is the physical hardware address (MAC address).
-	HWAddr net.HardwareAddr `json:"mac"`
-
-	// IP is the IP address leased to the client.
-	IP netip.Addr `json:"ip"`
-
-	// IsStatic defines if the lease is static.
-	IsStatic bool `json:"static"`
-}
-
-// Clone returns a deep copy of l.
-func (l *Lease) Clone() (clone *Lease) {
-	if l == nil {
-		return nil
-	}
-
-	return &Lease{
-		Expiry:   l.Expiry,
-		Hostname: l.Hostname,
-		HWAddr:   slices.Clone(l.HWAddr),
-		IP:       l.IP,
-		IsStatic: l.IsStatic,
-	}
-}
-
-// IsBlocklisted returns true if the lease is blocklisted.
-//
-// TODO(a.garipov): Just make it a boolean field.
-func (l *Lease) IsBlocklisted() (ok bool) {
-	if len(l.HWAddr) == 0 {
-		return false
-	}
-
-	for _, b := range l.HWAddr {
-		if b != 0 {
-			return false
-		}
-	}
-
-	return true
-}
-
-// MarshalJSON implements the json.Marshaler interface for Lease.
-func (l Lease) MarshalJSON() ([]byte, error) {
-	var expiryStr string
-	if !l.IsStatic {
-		// The front-end is waiting for RFC 3999 format of the time
-		// value.  It also shouldn't got an Expiry field for static
-		// leases.
-		//
-		// See https://github.com/AdguardTeam/AdGuardHome/issues/2692.
-		expiryStr = l.Expiry.Format(time.RFC3339)
-	}
-
-	type lease Lease
-	return json.Marshal(&struct {
-		HWAddr string `json:"mac"`
-		Expiry string `json:"expires,omitempty"`
-		lease
-	}{
-		HWAddr: l.HWAddr.String(),
-		Expiry: expiryStr,
-		lease:  lease(l),
-	})
-}
-
-// UnmarshalJSON implements the json.Unmarshaler interface for *Lease.
-func (l *Lease) UnmarshalJSON(data []byte) (err error) {
-	type lease Lease
-	aux := struct {
-		*lease
-		HWAddr string `json:"mac"`
-	}{
-		lease: (*lease)(l),
-	}
-	if err = json.Unmarshal(data, &aux); err != nil {
-		return err
-	}
-
-	l.HWAddr, err = net.ParseMAC(aux.HWAddr)
-	if err != nil {
-		return fmt.Errorf("couldn't parse MAC address: %w", err)
-	}
-
-	return nil
-}
-
 // OnLeaseChangedT is a callback for lease changes.
 type OnLeaseChangedT func(flags int)
 
@@ -370,19 +269,7 @@ func (s *server) Stop() (err error) {
 
 // Leases returns the list of active DHCP leases.
 func (s *server) Leases() (leases []*dhcpsvc.Lease) {
-	ls := append(s.srv4.GetLeases(LeasesAll), s.srv6.GetLeases(LeasesAll)...)
+	return append(s.srv4.GetLeases(LeasesAll), s.srv6.GetLeases(LeasesAll)...)
-	leases = make([]*dhcpsvc.Lease, len(ls))
-	for i, l := range ls {
-		leases[i] = &dhcpsvc.Lease{
-			Expiry:   l.Expiry,
-			Hostname: l.Hostname,
-			HWAddr:   l.HWAddr,
-			IP:       l.IP,
-			IsStatic: l.IsStatic,
-		}
-	}
-
-	return leases
 }
 
 // MACByIP returns a MAC address by the IP address of its lease, if there is
@@ -414,6 +301,6 @@ func (s *server) IPByHost(host string) (ip netip.Addr) {
 }
 
 // AddStaticLease - add static v4 lease
-func (s *server) AddStaticLease(l *Lease) error {
+func (s *server) AddStaticLease(l *dhcpsvc.Lease) error {
 	return s.srv4.AddStaticLease(l)
 }

internal/dhcpd/dhcpd_unix_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -44,7 +45,7 @@ func TestDB(t *testing.T) {
 	s.srv6, err = v6Create(V6ServerConf{})
 	require.NoError(t, err)
 
-	leases := []*Lease{{
+	leases := []*dhcpsvc.Lease{{
 		Expiry:   time.Now().Add(time.Hour),
 		Hostname: "static-1.local",
 		HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},

internal/dhcpd/http_unix.go

@@ -93,13 +93,13 @@ func leasesToStatic(leases []*dhcpsvc.Lease) (static []*leaseStatic) {
 }
 
 // toLease converts leaseStatic to Lease or returns error.
-func (l *leaseStatic) toLease() (lease *Lease, err error) {
+func (l *leaseStatic) toLease() (lease *dhcpsvc.Lease, err error) {
 	addr, err := net.ParseMAC(l.HWAddr)
 	if err != nil {
 		return nil, fmt.Errorf("couldn't parse MAC address: %w", err)
 	}
 
-	return &Lease{
+	return &dhcpsvc.Lease{
 		HWAddr:   addr,
 		IP:       l.IP,
 		Hostname: l.Hostname,
@@ -593,7 +593,7 @@ func setOtherDHCPResult(ifaceName string, result *dhcpSearchResult) {
 
 // parseLease parses a lease from r.  If there is no error returns DHCPServer
 // and *Lease. r must be non-nil.
-func (s *server) parseLease(r io.Reader) (srv DHCPServer, lease *Lease, err error) {
+func (s *server) parseLease(r io.Reader) (srv DHCPServer, lease *dhcpsvc.Lease, err error) {
 	l := &leaseStatic{}
 	err = json.NewDecoder(r).Decode(l)
 	if err != nil {

internal/dhcpd/migrate.go

@@ -2,6 +2,7 @@ package dhcpd
 
 import (
 	"encoding/json"
+	"fmt"
 	"net"
 	"net/netip"
 	"os"
@@ -25,9 +26,9 @@ const (
 	dbFilename = "leases.db"
 )
 
-// leaseJSON is the structure of stored lease.
+// leaseJSON is the structure of stored lease in a legacy database.
 //
-// Deprecated:  Use [Lease].
+// Deprecated:  Use [dbLease].
 type leaseJSON struct {
 	HWAddr   []byte `json:"mac"`
 	IP       []byte `json:"ip"`
@@ -35,13 +36,28 @@ type leaseJSON struct {
 	Expiry   int64  `json:"exp"`
 }
 
-func normalizeIP(ip net.IP) net.IP {
+// readOldDB reads the old database from the given path.
-	ip4 := ip.To4()
+func readOldDB(path string) (leases []*leaseJSON, err error) {
-	if ip4 != nil {
+	// #nosec G304 -- Trust this path, since it's taken from the old file name
-		return ip4
+	// relative to the working directory and should generally be considered
+	// safe.
+	file, err := os.Open(path)
+	if errors.Is(err, os.ErrNotExist) {
+		// Nothing to migrate.
+		return nil, nil
+	} else if err != nil {
+		// Don't wrap the error since it's informative enough as is.
+		return nil, err
+	}
+	defer func() { err = errors.WithDeferred(err, file.Close()) }()
+
+	leases = []*leaseJSON{}
+	err = json.NewDecoder(file).Decode(&leases)
+	if err != nil {
+		return nil, fmt.Errorf("decoding old db: %w", err)
 	}
 
-	return ip
+	return leases, nil
 }
 
 // migrateDB migrates stored leases if necessary.
@@ -51,59 +67,50 @@ func migrateDB(conf *ServerConfig) (err error) {
 	oldLeasesPath := filepath.Join(conf.WorkDir, dbFilename)
 	dataDirPath := filepath.Join(conf.DataDir, dataFilename)
 
-	// #nosec G304 -- Trust this path, since it's taken from the old file name
+	oldLeases, err := readOldDB(oldLeasesPath)
-	// relative to the working directory and should generally be considered
+	if err != nil {
-	// safe.
+		// Don't wrap the error since it's informative enough as is.
-	file, err := os.Open(oldLeasesPath)
+		return err
-	if errors.Is(err, os.ErrNotExist) {
+	} else if oldLeases == nil {
 		// Nothing to migrate.
 		return nil
-	} else if err != nil {
-		// Don't wrap the error since it's informative enough as is.
-		return err
 	}
 
-	ljs := []leaseJSON{}
+	leases := make([]*dbLease, 0, len(oldLeases))
-	err = json.NewDecoder(file).Decode(&ljs)
+	for _, l := range oldLeases {
-	if err != nil {
+		l.IP = normalizeIP(l.IP)
-		// Don't wrap the error since it's informative enough as is.
+		ip, ok := netip.AddrFromSlice(l.IP)
-		return err
-	}
-
-	err = file.Close()
-	if err != nil {
-		// Don't wrap the error since it's informative enough as is.
-		return err
-	}
-
-	leases := []*Lease{}
-
-	for _, lj := range ljs {
-		lj.IP = normalizeIP(lj.IP)
-
-		ip, ok := netip.AddrFromSlice(lj.IP)
 		if !ok {
-			log.Info("dhcp: invalid IP: %s", lj.IP)
+			log.Info("dhcp: invalid IP: %s", l.IP)
 
 			continue
 		}
 
-		lease := &Lease{
+		leases = append(leases, &dbLease{
-			Expiry:   time.Unix(lj.Expiry, 0),
+			Expiry:   time.Unix(l.Expiry, 0).Format(time.RFC3339),
-			Hostname: lj.Hostname,
+			Hostname: l.Hostname,
-			HWAddr:   lj.HWAddr,
+			HWAddr:   net.HardwareAddr(l.HWAddr).String(),
 			IP:       ip,
-			IsStatic: lj.Expiry == leaseExpireStatic,
+			IsStatic: l.Expiry == leaseExpireStatic,
-		}
+		})
-
-		leases = append(leases, lease)
 	}
 
 	err = writeDB(dataDirPath, leases)
 	if err != nil {
-		// Don't wrap the error since it's informative enough as is.
+		// Don't wrap the error since an annotation deferred already.
 		return err
 	}
 
 	return os.Remove(oldLeasesPath)
 }
+
+// normalizeIP converts the given IP address to IPv4 if it's IPv4-mapped IPv6,
+// or leaves it as is otherwise.
+func normalizeIP(ip net.IP) (normalized net.IP) {
+	normalized = ip.To4()
+	if normalized != nil {
+		return normalized
+	}
+
+	return ip
+}

internal/dhcpd/migrate_internal_test.go

@@ -2,7 +2,6 @@ package dhcpd
 
 import (
 	"encoding/json"
-	"net"
 	"net/netip"
 	"os"
 	"path/filepath"
@@ -27,16 +26,16 @@ func TestMigrateDB(t *testing.T) {
 	err := os.WriteFile(oldLeasesPath, []byte(testData), 0o644)
 	require.NoError(t, err)
 
-	wantLeases := []*Lease{{
+	wantLeases := []*dbLease{{
-		Expiry:   time.Time{},
+		Expiry:   time.Unix(1, 0).Format(time.RFC3339),
 		Hostname: "test1",
-		HWAddr:   net.HardwareAddr{0x11, 0x22, 0x33, 0x44, 0x55, 0x66},
+		HWAddr:   "11:22:33:44:55:66",
 		IP:       netip.MustParseAddr("1.2.3.4"),
 		IsStatic: true,
 	}, {
-		Expiry:   time.Unix(1231231231, 0),
+		Expiry:   time.Unix(1231231231, 0).Format(time.RFC3339),
 		Hostname: "test2",
-		HWAddr:   net.HardwareAddr{0x66, 0x55, 0x44, 0x33, 0x22, 0x11},
+		HWAddr:   "66:55:44:33:22:11",
 		IP:       netip.MustParseAddr("4.3.2.1"),
 		IsStatic: false,
 	}}
@@ -62,12 +61,12 @@ func TestMigrateDB(t *testing.T) {
 
 	leases := dl.Leases
 
-	for i, wl := range wantLeases {
+	for i, wantLease := range wantLeases {
-		assert.Equal(t, wl.Hostname, leases[i].Hostname)
+		assert.Equal(t, wantLease.Hostname, leases[i].Hostname)
-		assert.Equal(t, wl.HWAddr, leases[i].HWAddr)
+		assert.Equal(t, wantLease.HWAddr, leases[i].HWAddr)
-		assert.Equal(t, wl.IP, leases[i].IP)
+		assert.Equal(t, wantLease.IP, leases[i].IP)
-		assert.Equal(t, wl.IsStatic, leases[i].IsStatic)
+		assert.Equal(t, wantLease.IsStatic, leases[i].IsStatic)
 
-		require.True(t, wl.Expiry.Equal(leases[i].Expiry))
+		require.Equal(t, wantLease.Expiry, leases[i].Expiry)
 	}
 }

internal/dhcpd/v46_windows.go

@@ -7,6 +7,8 @@ package dhcpd
 import (
 	"net"
 	"net/netip"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 )
 
 type winServer struct{}
@@ -14,12 +16,12 @@ type winServer struct{}
 // type check
 var _ DHCPServer = winServer{}
 
-func (winServer) ResetLeases(_ []*Lease) (err error)              { return nil }
+func (winServer) ResetLeases(_ []*dhcpsvc.Lease) (err error)           { return nil }
-func (winServer) GetLeases(_ GetLeasesFlags) (leases []*Lease)    { return nil }
+func (winServer) GetLeases(_ GetLeasesFlags) (leases []*dhcpsvc.Lease) { return nil }
-func (winServer) getLeasesRef() []*Lease                          { return nil }
+func (winServer) getLeasesRef() []*dhcpsvc.Lease                       { return nil }
-func (winServer) AddStaticLease(_ *Lease) (err error)             { return nil }
+func (winServer) AddStaticLease(_ *dhcpsvc.Lease) (err error)          { return nil }
-func (winServer) RemoveStaticLease(_ *Lease) (err error)          { return nil }
+func (winServer) RemoveStaticLease(_ *dhcpsvc.Lease) (err error)       { return nil }
-func (winServer) UpdateStaticLease(_ *Lease) (err error)          { return nil }
+func (winServer) UpdateStaticLease(_ *dhcpsvc.Lease) (err error)       { return nil }
 func (winServer) FindMACbyIP(_ netip.Addr) (mac net.HardwareAddr)      { return nil }
 func (winServer) WriteDiskConfig4(_ *V4ServerConf)                     {}
 func (winServer) WriteDiskConfig6(_ *V6ServerConf)                     {}

internal/dhcpd/v4_unix.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/errors"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/netutil"
@@ -38,7 +39,7 @@ type v4Server struct {
 	// have intersections with [implicitOpts].
 	explicitOpts dhcpv4.Options
 
-	// leasesLock protects leases, leaseHosts, and leasedOffsets.
+	// leasesLock protects leases, hostsIndex, ipIndex, and leasedOffsets.
 	leasesLock sync.Mutex
 
 	// leasedOffsets contains offsets from conf.ipRange.start that have been
@@ -46,13 +47,13 @@ type v4Server struct {
 	leasedOffsets *bitSet
 
 	// leases contains all dynamic and static leases.
-	leases []*Lease
+	leases []*dhcpsvc.Lease
 
 	// hostsIndex is the set of all hostnames of all known DHCP clients.
-	hostsIndex map[string]*Lease
+	hostsIndex map[string]*dhcpsvc.Lease
 
 	// ipIndex is an index of leases by their IP addresses.
-	ipIndex map[netip.Addr]*Lease
+	ipIndex map[netip.Addr]*dhcpsvc.Lease
 }
 
 func (s *v4Server) enabled() (ok bool) {
@@ -141,7 +142,7 @@ func (s *v4Server) IPByHost(host string) (ip netip.Addr) {
 }
 
 // ResetLeases resets leases.
-func (s *v4Server) ResetLeases(leases []*Lease) (err error) {
+func (s *v4Server) ResetLeases(leases []*dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv4: %w") }()
 
 	if s.conf == nil {
@@ -152,8 +153,8 @@ func (s *v4Server) ResetLeases(leases []*Lease) (err error) {
 	defer s.leasesLock.Unlock()
 
 	s.leasedOffsets = newBitSet()
-	s.hostsIndex = make(map[string]*Lease, len(leases))
+	s.hostsIndex = make(map[string]*dhcpsvc.Lease, len(leases))
-	s.ipIndex = make(map[netip.Addr]*Lease, len(leases))
+	s.ipIndex = make(map[netip.Addr]*dhcpsvc.Lease, len(leases))
 	s.leases = nil
 
 	for _, l := range leases {
@@ -173,14 +174,14 @@ func (s *v4Server) ResetLeases(leases []*Lease) (err error) {
 }
 
 // getLeasesRef returns the actual leases slice.  For internal use only.
-func (s *v4Server) getLeasesRef() []*Lease {
+func (s *v4Server) getLeasesRef() []*dhcpsvc.Lease {
 	return s.leases
 }
 
 // isBlocklisted returns true if this lease holds a blocklisted IP.
 //
 // TODO(a.garipov): Make a method of *Lease?
-func (s *v4Server) isBlocklisted(l *Lease) (ok bool) {
+func (s *v4Server) isBlocklisted(l *dhcpsvc.Lease) (ok bool) {
 	if len(l.HWAddr) == 0 {
 		return false
 	}
@@ -196,11 +197,11 @@ func (s *v4Server) isBlocklisted(l *Lease) (ok bool) {
 
 // GetLeases returns the list of current DHCP leases.  It is safe for concurrent
 // use.
-func (s *v4Server) GetLeases(flags GetLeasesFlags) (leases []*Lease) {
+func (s *v4Server) GetLeases(flags GetLeasesFlags) (leases []*dhcpsvc.Lease) {
 	// The function shouldn't return nil, because zero-length slice behaves
 	// differently in cases like marshalling.  Our front-end also requires
 	// a non-nil value in the response.
-	leases = []*Lease{}
+	leases = []*dhcpsvc.Lease{}
 
 	getDynamic := flags&LeasesDynamic != 0
 	getStatic := flags&LeasesStatic != 0
@@ -248,7 +249,7 @@ func (s *v4Server) FindMACbyIP(ip netip.Addr) (mac net.HardwareAddr) {
 const defaultHwAddrLen = 6
 
 // Add the specified IP to the black list for a time period
-func (s *v4Server) blocklistLease(l *Lease) {
+func (s *v4Server) blocklistLease(l *dhcpsvc.Lease) {
 	l.HWAddr = make(net.HardwareAddr, defaultHwAddrLen)
 	l.Hostname = ""
 	l.Expiry = time.Now().Add(s.conf.leaseTime)
@@ -284,7 +285,7 @@ func (s *v4Server) rmLeaseByIndex(i int) {
 // Return error if a static lease is found
 //
 // TODO(s.chzhen):  Refactor the code.
-func (s *v4Server) rmDynamicLease(lease *Lease) (err error) {
+func (s *v4Server) rmDynamicLease(lease *dhcpsvc.Lease) (err error) {
 	for i, l := range s.leases {
 		isStatic := l.IsStatic
 
@@ -320,7 +321,7 @@ const (
 )
 
 // addLease adds a dynamic or static lease.
-func (s *v4Server) addLease(l *Lease) (err error) {
+func (s *v4Server) addLease(l *dhcpsvc.Lease) (err error) {
 	r := s.conf.ipRange
 	leaseIP := net.IP(l.IP.AsSlice())
 	offset, inOffset := r.offset(leaseIP)
@@ -352,7 +353,7 @@ func (s *v4Server) addLease(l *Lease) (err error) {
 }
 
 // rmLease removes a lease with the same properties.
-func (s *v4Server) rmLease(lease *Lease) (err error) {
+func (s *v4Server) rmLease(lease *dhcpsvc.Lease) (err error) {
 	if len(s.leases) == 0 {
 		return nil
 	}
@@ -378,7 +379,7 @@ const ErrUnconfigured errors.Error = "server is unconfigured"
 
 // AddStaticLease implements the DHCPServer interface for *v4Server.  It is
 // safe for concurrent use.
-func (s *v4Server) AddStaticLease(l *Lease) (err error) {
+func (s *v4Server) AddStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv4: adding static lease: %w") }()
 
 	if s.conf == nil {
@@ -435,7 +436,7 @@ func (s *v4Server) AddStaticLease(l *Lease) (err error) {
 }
 
 // UpdateStaticLease updates IP, hostname of the static lease.
-func (s *v4Server) UpdateStaticLease(l *Lease) (err error) {
+func (s *v4Server) UpdateStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() {
 		if err != nil {
 			err = errors.Annotate(err, "dhcpv4: updating static lease: %w")
@@ -474,7 +475,7 @@ func (s *v4Server) UpdateStaticLease(l *Lease) (err error) {
 }
 
 // validateStaticLease returns an error if the static lease is invalid.
-func (s *v4Server) validateStaticLease(l *Lease) (err error) {
+func (s *v4Server) validateStaticLease(l *dhcpsvc.Lease) (err error) {
 	hostname, err := normalizeHostname(l.Hostname)
 	if err != nil {
 		// Don't wrap the error, because it's informative enough as is.
@@ -511,7 +512,7 @@ func (s *v4Server) validateStaticLease(l *Lease) (err error) {
 
 // updateStaticLease safe removes dynamic lease with the same properties and
 // then adds a static lease l.
-func (s *v4Server) updateStaticLease(l *Lease) (err error) {
+func (s *v4Server) updateStaticLease(l *dhcpsvc.Lease) (err error) {
 	s.leasesLock.Lock()
 	defer s.leasesLock.Unlock()
 
@@ -529,7 +530,7 @@ func (s *v4Server) updateStaticLease(l *Lease) (err error) {
 }
 
 // RemoveStaticLease removes a static lease.  It is safe for concurrent use.
-func (s *v4Server) RemoveStaticLease(l *Lease) (err error) {
+func (s *v4Server) RemoveStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv4: %w") }()
 
 	if s.conf == nil {
@@ -606,7 +607,7 @@ func (s *v4Server) addrAvailable(target net.IP) (avail bool) {
 }
 
 // findLease finds a lease by its MAC-address.
-func (s *v4Server) findLease(mac net.HardwareAddr) (l *Lease) {
+func (s *v4Server) findLease(mac net.HardwareAddr) (l *dhcpsvc.Lease) {
 	for _, l = range s.leases {
 		if bytes.Equal(mac, l.HWAddr) {
 			return l
@@ -646,8 +647,8 @@ func (s *v4Server) findExpiredLease() int {
 
 // reserveLease reserves a lease for a client by its MAC-address.  It returns
 // nil if it couldn't allocate a new lease.
-func (s *v4Server) reserveLease(mac net.HardwareAddr) (l *Lease, err error) {
+func (s *v4Server) reserveLease(mac net.HardwareAddr) (l *dhcpsvc.Lease, err error) {
-	l = &Lease{HWAddr: slices.Clone(mac)}
+	l = &dhcpsvc.Lease{HWAddr: slices.Clone(mac)}
 
 	nextIP := s.nextIP()
 	if nextIP == nil {
@@ -679,7 +680,7 @@ func (s *v4Server) reserveLease(mac net.HardwareAddr) (l *Lease, err error) {
 // commitLease refreshes l's values.  It takes the desired hostname into account
 // when setting it into the lease, but generates a unique one if the provided
 // can't be used.
-func (s *v4Server) commitLease(l *Lease, hostname string) {
+func (s *v4Server) commitLease(l *dhcpsvc.Lease, hostname string) {
 	prev := l.Hostname
 	hostname = s.validHostnameForClient(hostname, l.IP)
 
@@ -709,7 +710,7 @@ func (s *v4Server) commitLease(l *Lease, hostname string) {
 
 // allocateLease allocates a new lease for the MAC address.  If there are no IP
 // addresses left, both l and err are nil.
-func (s *v4Server) allocateLease(mac net.HardwareAddr) (l *Lease, err error) {
+func (s *v4Server) allocateLease(mac net.HardwareAddr) (l *dhcpsvc.Lease, err error) {
 	for {
 		l, err = s.reserveLease(mac)
 		if err != nil {
@@ -728,7 +729,7 @@ func (s *v4Server) allocateLease(mac net.HardwareAddr) (l *Lease, err error) {
 }
 
 // handleDiscover is the handler for the DHCP Discover request.
-func (s *v4Server) handleDiscover(req, resp *dhcpv4.DHCPv4) (l *Lease, err error) {
+func (s *v4Server) handleDiscover(req, resp *dhcpv4.DHCPv4) (l *dhcpsvc.Lease, err error) {
 	mac := req.ClientHWAddr
 
 	defer s.conf.notify(LeaseChangedDBStore)
@@ -787,7 +788,7 @@ func OptionFQDN(fqdn string) (opt dhcpv4.Option) {
 // checkLease checks if the pair of mac and ip is already leased.  The mismatch
 // is true when the existing lease has the same hardware address but differs in
 // its IP address.
-func (s *v4Server) checkLease(mac net.HardwareAddr, ip net.IP) (lease *Lease, mismatch bool) {
+func (s *v4Server) checkLease(mac net.HardwareAddr, ip net.IP) (l *dhcpsvc.Lease, mismatch bool) {
 	s.leasesLock.Lock()
 	defer s.leasesLock.Unlock()
 
@@ -798,7 +799,7 @@ func (s *v4Server) checkLease(mac net.HardwareAddr, ip net.IP) (lease *Lease, mi
 		return nil, false
 	}
 
-	for _, l := range s.leases {
+	for _, l = range s.leases {
 		if !bytes.Equal(l.HWAddr, mac) {
 			continue
 		}
@@ -823,7 +824,7 @@ func (s *v4Server) handleSelecting(
 	req *dhcpv4.DHCPv4,
 	reqIP net.IP,
 	sid net.IP,
-) (l *Lease, needsReply bool) {
+) (l *dhcpsvc.Lease, needsReply bool) {
 	// Client inserts the address of the selected server in server identifier,
 	// ciaddr MUST be zero.
 	mac := req.ClientHWAddr
@@ -857,7 +858,10 @@ func (s *v4Server) handleSelecting(
 }
 
 // handleInitReboot handles the DHCPREQUEST generated during INIT-REBOOT state.
-func (s *v4Server) handleInitReboot(req *dhcpv4.DHCPv4, reqIP net.IP) (l *Lease, needsReply bool) {
+func (s *v4Server) handleInitReboot(
+	req *dhcpv4.DHCPv4,
+	reqIP net.IP,
+) (l *dhcpsvc.Lease, needsReply bool) {
 	mac := req.ClientHWAddr
 
 	ip4 := reqIP.To4()
@@ -899,7 +903,7 @@ func (s *v4Server) handleInitReboot(req *dhcpv4.DHCPv4, reqIP net.IP) (l *Lease,
 
 // handleRenew handles the DHCPREQUEST generated during RENEWING or REBINDING
 // state.
-func (s *v4Server) handleRenew(req *dhcpv4.DHCPv4) (l *Lease, needsReply bool) {
+func (s *v4Server) handleRenew(req *dhcpv4.DHCPv4) (l *dhcpsvc.Lease, needsReply bool) {
 	mac := req.ClientHWAddr
 
 	// ciaddr MUST be filled in with client's IP address.
@@ -926,7 +930,7 @@ func (s *v4Server) handleRenew(req *dhcpv4.DHCPv4) (l *Lease, needsReply bool) {
 
 // handleByRequestType handles the DHCPREQUEST according to the state during
 // which it's generated by client.
-func (s *v4Server) handleByRequestType(req *dhcpv4.DHCPv4) (lease *Lease, needsReply bool) {
+func (s *v4Server) handleByRequestType(req *dhcpv4.DHCPv4) (lease *dhcpsvc.Lease, needsReply bool) {
 	reqIP, sid := req.RequestedIPAddress(), req.ServerIdentifier()
 
 	if sid != nil && !sid.IsUnspecified() {
@@ -950,7 +954,7 @@ func (s *v4Server) handleByRequestType(req *dhcpv4.DHCPv4) (lease *Lease, needsR
 // handleRequest is the handler for a DHCPREQUEST message.
 //
 // See https://datatracker.ietf.org/doc/html/rfc2131#section-4.3.2.
-func (s *v4Server) handleRequest(req, resp *dhcpv4.DHCPv4) (lease *Lease, needsReply bool) {
+func (s *v4Server) handleRequest(req, resp *dhcpv4.DHCPv4) (lease *dhcpsvc.Lease, needsReply bool) {
 	lease, needsReply = s.handleByRequestType(req)
 	if lease == nil {
 		return nil, needsReply
@@ -1043,7 +1047,7 @@ func (s *v4Server) handleDecline(req, resp *dhcpv4.DHCPv4) (err error) {
 }
 
 // findLeaseForIP returns a lease for provided ip and mac.
-func (s *v4Server) findLeaseForIP(ip net.IP, mac net.HardwareAddr) (l *Lease) {
+func (s *v4Server) findLeaseForIP(ip net.IP, mac net.HardwareAddr) (l *dhcpsvc.Lease) {
 	netIP, ok := netip.AddrFromSlice(ip)
 	if !ok {
 		log.Info("dhcpv4: invalid IP: %s", ip)
@@ -1106,7 +1110,11 @@ func (s *v4Server) handleRelease(req, resp *dhcpv4.DHCPv4) (err error) {
 }
 
 // messageHandler describes a DHCPv4 message handler function.
-type messageHandler func(s *v4Server, req, resp *dhcpv4.DHCPv4) (rCode int, l *Lease, err error)
+type messageHandler func(
+	s *v4Server,
+	req *dhcpv4.DHCPv4,
+	resp *dhcpv4.DHCPv4,
+) (rCode int, l *dhcpsvc.Lease, err error)
 
 // messageHandlers is a map of handlers for various messages with message types
 // keys.
@@ -1115,7 +1123,7 @@ var messageHandlers = map[dhcpv4.MessageType]messageHandler{
 		s *v4Server,
 		req *dhcpv4.DHCPv4,
 		resp *dhcpv4.DHCPv4,
-	) (rCode int, l *Lease, err error) {
+	) (rCode int, l *dhcpsvc.Lease, err error) {
 		l, err = s.handleDiscover(req, resp)
 		if err != nil {
 			return 0, nil, fmt.Errorf("handling discover: %s", err)
@@ -1131,7 +1139,7 @@ var messageHandlers = map[dhcpv4.MessageType]messageHandler{
 		s *v4Server,
 		req *dhcpv4.DHCPv4,
 		resp *dhcpv4.DHCPv4,
-	) (rCode int, l *Lease, err error) {
+	) (rCode int, l *dhcpsvc.Lease, err error) {
 		var toReply bool
 		l, toReply = s.handleRequest(req, resp)
 		if l == nil {
@@ -1149,7 +1157,7 @@ var messageHandlers = map[dhcpv4.MessageType]messageHandler{
 		s *v4Server,
 		req *dhcpv4.DHCPv4,
 		resp *dhcpv4.DHCPv4,
-	) (rCode int, l *Lease, err error) {
+	) (rCode int, l *dhcpsvc.Lease, err error) {
 		err = s.handleDecline(req, resp)
 		if err != nil {
 			return 0, nil, fmt.Errorf("handling decline: %s", err)
@@ -1161,7 +1169,7 @@ var messageHandlers = map[dhcpv4.MessageType]messageHandler{
 		s *v4Server,
 		req *dhcpv4.DHCPv4,
 		resp *dhcpv4.DHCPv4,
-	) (rCode int, l *Lease, err error) {
+	) (rCode int, l *dhcpsvc.Lease, err error) {
 		err = s.handleRelease(req, resp)
 		if err != nil {
 			return 0, nil, fmt.Errorf("handling release: %s", err)
@@ -1402,8 +1410,8 @@ func (s *v4Server) Stop() (err error) {
 // Create DHCPv4 server
 func v4Create(conf *V4ServerConf) (srv *v4Server, err error) {
 	s := &v4Server{
-		hostsIndex: map[string]*Lease{},
+		hostsIndex: map[string]*dhcpsvc.Lease{},
-		ipIndex:    map[netip.Addr]*Lease{},
+		ipIndex:    map[netip.Addr]*dhcpsvc.Lease{},
 	}
 
 	err = conf.Validate()

internal/dhcpd/v4_unix_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/netutil"
 	"github.com/AdguardTeam/golibs/stringutil"
 	"github.com/AdguardTeam/golibs/testutil"
@@ -67,7 +68,7 @@ func TestV4Server_leasing(t *testing.T) {
 	s := defaultSrv(t)
 
 	t.Run("add_static", func(t *testing.T) {
-		err := s.AddStaticLease(&Lease{
+		err := s.AddStaticLease(&dhcpsvc.Lease{
 			Hostname: staticName,
 			HWAddr:   staticMAC,
 			IP:       staticIP,
@@ -76,7 +77,7 @@ func TestV4Server_leasing(t *testing.T) {
 		require.NoError(t, err)
 
 		t.Run("same_name", func(t *testing.T) {
-			err = s.AddStaticLease(&Lease{
+			err = s.AddStaticLease(&dhcpsvc.Lease{
 				Hostname: staticName,
 				HWAddr:   anotherMAC,
 				IP:       anotherIP,
@@ -90,7 +91,7 @@ func TestV4Server_leasing(t *testing.T) {
 				"dynamic leases for " + anotherIP.String() +
 				" (" + staticMAC.String() + "): static lease already exists"
 
-			err = s.AddStaticLease(&Lease{
+			err = s.AddStaticLease(&dhcpsvc.Lease{
 				Hostname: anotherName,
 				HWAddr:   staticMAC,
 				IP:       anotherIP,
@@ -104,7 +105,7 @@ func TestV4Server_leasing(t *testing.T) {
 				"dynamic leases for " + staticIP.String() +
 				" (" + anotherMAC.String() + "): static lease already exists"
 
-			err = s.AddStaticLease(&Lease{
+			err = s.AddStaticLease(&dhcpsvc.Lease{
 				Hostname: anotherName,
 				HWAddr:   anotherMAC,
 				IP:       staticIP,
@@ -208,11 +209,11 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 	require.Empty(t, ls)
 
 	testCases := []struct {
-		lease      *Lease
+		lease      *dhcpsvc.Lease
 		name       string
 		wantErrMsg string
 	}{{
-		lease: &Lease{
+		lease: &dhcpsvc.Lease{
 			Hostname: "success.local",
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 			IP:       netip.MustParseAddr("192.168.10.150"),
@@ -220,7 +221,7 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 		name:       "success",
 		wantErrMsg: "",
 	}, {
-		lease: &Lease{
+		lease: &dhcpsvc.Lease{
 			Hostname: "probably-router.local",
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 			IP:       DefaultGatewayIP,
@@ -229,7 +230,7 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 		wantErrMsg: "dhcpv4: adding static lease: " +
 			`can't assign the gateway IP "192.168.10.1" to the lease`,
 	}, {
-		lease: &Lease{
+		lease: &dhcpsvc.Lease{
 			Hostname: "ip6.local",
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 			IP:       netip.MustParseAddr("ffff::1"),
@@ -238,7 +239,7 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 		wantErrMsg: `dhcpv4: adding static lease: ` +
 			`invalid IP "ffff::1": only IPv4 is supported`,
 	}, {
-		lease: &Lease{
+		lease: &dhcpsvc.Lease{
 			Hostname: "bad-mac.local",
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA},
 			IP:       netip.MustParseAddr("192.168.10.150"),
@@ -247,7 +248,7 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 		wantErrMsg: `dhcpv4: adding static lease: bad mac address "aa:aa": ` +
 			`bad mac address length 2, allowed: [6 8 20]`,
 	}, {
-		lease: &Lease{
+		lease: &dhcpsvc.Lease{
 			Hostname: "bad-lbl-.local",
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 			IP:       netip.MustParseAddr("192.168.10.150"),
@@ -266,7 +267,7 @@ func TestV4Server_AddRemove_static(t *testing.T) {
 				return
 			}
 
-			err = s.RemoveStaticLease(&Lease{
+			err = s.RemoveStaticLease(&dhcpsvc.Lease{
 				IP:     tc.lease.IP,
 				HWAddr: tc.lease.HWAddr,
 			})
@@ -289,7 +290,7 @@ func TestV4_AddReplace(t *testing.T) {
 	s, ok := sIface.(*v4Server)
 	require.True(t, ok)
 
-	dynLeases := []Lease{{
+	dynLeases := []dhcpsvc.Lease{{
 		Hostname: "dynamic-1.local",
 		HWAddr:   net.HardwareAddr{0x11, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 		IP:       netip.MustParseAddr("192.168.10.150"),
@@ -304,7 +305,7 @@ func TestV4_AddReplace(t *testing.T) {
 		require.NoError(t, err)
 	}
 
-	stLeases := []*Lease{{
+	stLeases := []*dhcpsvc.Lease{{
 		Hostname: "static-1.local",
 		HWAddr:   net.HardwareAddr{0x33, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 		IP:       netip.MustParseAddr("192.168.10.150"),
@@ -513,7 +514,7 @@ func TestV4StaticLease_Get(t *testing.T) {
 	s.conf.dnsIPAddrs = []netip.Addr{dnsAddr}
 	s.implicitOpts.Update(dhcpv4.OptDNS(dnsAddr.AsSlice()))
 
-	l := &Lease{
+	l := &dhcpsvc.Lease{
 		Hostname: "static-1.local",
 		HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 		IP:       netip.MustParseAddr("192.168.10.150"),
@@ -779,7 +780,7 @@ func TestV4Server_FindMACbyIP(t *testing.T) {
 	anotherMAC := net.HardwareAddr{0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB}
 
 	s := &v4Server{
-		leases: []*Lease{{
+		leases: []*dhcpsvc.Lease{{
 			Hostname: staticName,
 			HWAddr:   staticMAC,
 			IP:       staticIP,
@@ -791,11 +792,11 @@ func TestV4Server_FindMACbyIP(t *testing.T) {
 			IP:       anotherIP,
 		}},
 	}
-	s.ipIndex = map[netip.Addr]*Lease{
+	s.ipIndex = map[netip.Addr]*dhcpsvc.Lease{
 		staticIP:  s.leases[0],
 		anotherIP: s.leases[1],
 	}
-	s.hostsIndex = map[string]*Lease{
+	s.hostsIndex = map[string]*dhcpsvc.Lease{
 		staticName:  s.leases[0],
 		anotherName: s.leases[1],
 	}
@@ -845,7 +846,7 @@ func TestV4Server_handleDecline(t *testing.T) {
 	s4, ok := s.(*v4Server)
 	require.True(t, ok)
 
-	s4.leases = []*Lease{{
+	s4.leases = []*dhcpsvc.Lease{{
 		Hostname: dynamicName,
 		HWAddr:   dynamicMAC,
 		IP:       dynamicIP,
@@ -887,7 +888,7 @@ func TestV4Server_handleRelease(t *testing.T) {
 	s4, ok := s.(*v4Server)
 	require.True(t, ok)
 
-	s4.leases = []*Lease{{
+	s4.leases = []*dhcpsvc.Lease{{
 		Hostname: dynamicName,
 		HWAddr:   dynamicMAC,
 		IP:       dynamicIP,

internal/dhcpd/v6_unix.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/AdguardTeam/golibs/errors"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/netutil"
@@ -31,7 +32,7 @@ type v6Server struct {
 	sid  dhcpv6.DUID
 	srv  *server6.Server
 
-	leases     []*Lease
+	leases     []*dhcpsvc.Lease
 	leasesLock sync.Mutex
 	ipAddrs    [256]byte
 }
@@ -87,7 +88,7 @@ func (s *v6Server) IPByHost(host string) (ip netip.Addr) {
 }
 
 // ResetLeases resets leases.
-func (s *v6Server) ResetLeases(leases []*Lease) (err error) {
+func (s *v6Server) ResetLeases(leases []*dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv6: %w") }()
 
 	s.leasesLock.Lock()
@@ -111,12 +112,14 @@ func (s *v6Server) ResetLeases(leases []*Lease) (err error) {
 
 // GetLeases returns the list of current DHCP leases.  It is safe for concurrent
 // use.
-func (s *v6Server) GetLeases(flags GetLeasesFlags) (leases []*Lease) {
+func (s *v6Server) GetLeases(flags GetLeasesFlags) (leases []*dhcpsvc.Lease) {
 	// The function shouldn't return nil value because zero-length slice
 	// behaves differently in cases like marshalling.  Our front-end also
 	// requires non-nil value in the response.
-	leases = []*Lease{}
+	leases = []*dhcpsvc.Lease{}
 	s.leasesLock.Lock()
+	defer s.leasesLock.Unlock()
+
 	for _, l := range s.leases {
 		if l.IsStatic {
 			if (flags & LeasesStatic) != 0 {
@@ -128,12 +131,12 @@ func (s *v6Server) GetLeases(flags GetLeasesFlags) (leases []*Lease) {
 			}
 		}
 	}
-	s.leasesLock.Unlock()
+
 	return leases
 }
 
 // getLeasesRef returns the actual leases slice.  For internal use only.
-func (s *v6Server) getLeasesRef() []*Lease {
+func (s *v6Server) getLeasesRef() []*dhcpsvc.Lease {
 	return s.leases
 }
 
@@ -174,7 +177,7 @@ func (s *v6Server) leaseRemoveSwapByIndex(i int) {
 
 // Remove a dynamic lease with the same properties
 // Return error if a static lease is found
-func (s *v6Server) rmDynamicLease(lease *Lease) (err error) {
+func (s *v6Server) rmDynamicLease(lease *dhcpsvc.Lease) (err error) {
 	for i := 0; i < len(s.leases); i++ {
 		l := s.leases[i]
 
@@ -204,7 +207,7 @@ func (s *v6Server) rmDynamicLease(lease *Lease) (err error) {
 }
 
 // AddStaticLease adds a static lease.  It is safe for concurrent use.
-func (s *v6Server) AddStaticLease(l *Lease) (err error) {
+func (s *v6Server) AddStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv6: %w") }()
 
 	if !l.IP.Is6() {
@@ -236,7 +239,7 @@ func (s *v6Server) AddStaticLease(l *Lease) (err error) {
 }
 
 // UpdateStaticLease updates IP, hostname of the static lease.
-func (s *v6Server) UpdateStaticLease(l *Lease) (err error) {
+func (s *v6Server) UpdateStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() {
 		if err != nil {
 			err = errors.Annotate(err, "dhcpv6: updating static lease: %w")
@@ -267,7 +270,7 @@ func (s *v6Server) UpdateStaticLease(l *Lease) (err error) {
 }
 
 // RemoveStaticLease removes a static lease.  It is safe for concurrent use.
-func (s *v6Server) RemoveStaticLease(l *Lease) (err error) {
+func (s *v6Server) RemoveStaticLease(l *dhcpsvc.Lease) (err error) {
 	defer func() { err = errors.Annotate(err, "dhcpv6: %w") }()
 
 	if !l.IP.Is6() {
@@ -292,7 +295,7 @@ func (s *v6Server) RemoveStaticLease(l *Lease) (err error) {
 }
 
 // Add a lease
-func (s *v6Server) addLease(l *Lease) {
+func (s *v6Server) addLease(l *dhcpsvc.Lease) {
 	s.leases = append(s.leases, l)
 	ip := l.IP.As16()
 	s.ipAddrs[ip[15]] = 1
@@ -300,7 +303,7 @@ func (s *v6Server) addLease(l *Lease) {
 }
 
 // Remove a lease with the same properties
-func (s *v6Server) rmLease(lease *Lease) (err error) {
+func (s *v6Server) rmLease(lease *dhcpsvc.Lease) (err error) {
 	for i, l := range s.leases {
 		if l.IP == lease.IP {
 			if !bytes.Equal(l.HWAddr, lease.HWAddr) ||
@@ -318,7 +321,7 @@ func (s *v6Server) rmLease(lease *Lease) (err error) {
 }
 
 // Find lease by MAC.
-func (s *v6Server) findLease(mac net.HardwareAddr) (lease *Lease) {
+func (s *v6Server) findLease(mac net.HardwareAddr) (lease *dhcpsvc.Lease) {
 	for i := range s.leases {
 		if bytes.Equal(mac, s.leases[i].HWAddr) {
 			return s.leases[i]
@@ -356,8 +359,8 @@ func (s *v6Server) findFreeIP() net.IP {
 }
 
 // Reserve lease for MAC
-func (s *v6Server) reserveLease(mac net.HardwareAddr) *Lease {
+func (s *v6Server) reserveLease(mac net.HardwareAddr) *dhcpsvc.Lease {
-	l := Lease{
+	l := dhcpsvc.Lease{
 		HWAddr: make([]byte, len(mac)),
 	}
 
@@ -390,7 +393,7 @@ func (s *v6Server) reserveLease(mac net.HardwareAddr) *Lease {
 	return &l
 }
 
-func (s *v6Server) commitDynamicLease(l *Lease) {
+func (s *v6Server) commitDynamicLease(l *dhcpsvc.Lease) {
 	l.Expiry = time.Now().Add(s.conf.leaseTime)
 
 	s.leasesLock.Lock()
@@ -438,7 +441,7 @@ func (s *v6Server) checkSID(msg *dhcpv6.Message) error {
 }
 
 // . IAAddress must be equal to the lease's IP
-func (s *v6Server) checkIA(msg *dhcpv6.Message, lease *Lease) error {
+func (s *v6Server) checkIA(msg *dhcpv6.Message, lease *dhcpsvc.Lease) error {
 	switch msg.Type() {
 	case dhcpv6.MessageTypeRequest,
 		dhcpv6.MessageTypeConfirm,
@@ -464,7 +467,7 @@ func (s *v6Server) checkIA(msg *dhcpv6.Message, lease *Lease) error {
 }
 
 // Store lease in DB (if necessary) and return lease life time
-func (s *v6Server) commitLease(msg *dhcpv6.Message, lease *Lease) time.Duration {
+func (s *v6Server) commitLease(msg *dhcpv6.Message, lease *dhcpsvc.Lease) time.Duration {
 	lifetime := s.conf.leaseTime
 
 	switch msg.Type() {
@@ -506,7 +509,7 @@ func (s *v6Server) process(msg *dhcpv6.Message, req, resp dhcpv6.DHCPv6) bool {
 		return false
 	}
 
-	var lease *Lease
+	var lease *dhcpsvc.Lease
 	func() {
 		s.leasesLock.Lock()
 		defer s.leasesLock.Unlock()

internal/dhcpd/v6_unix_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpsvc"
 	"github.com/insomniacslk/dhcp/dhcpv6"
 	"github.com/insomniacslk/dhcp/iana"
 	"github.com/stretchr/testify/assert"
@@ -28,7 +29,7 @@ func TestV6_AddRemove_static(t *testing.T) {
 	require.Empty(t, s.GetLeases(LeasesStatic))
 
 	// Add static lease.
-	l := &Lease{
+	l := &dhcpsvc.Lease{
 		IP:     netip.MustParseAddr("2001::1"),
 		HWAddr: net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 	}
@@ -47,7 +48,7 @@ func TestV6_AddRemove_static(t *testing.T) {
 	assert.True(t, ls[0].IsStatic)
 
 	// Try to remove non-existent static lease.
-	err = s.RemoveStaticLease(&Lease{
+	err = s.RemoveStaticLease(&dhcpsvc.Lease{
 		IP:     netip.MustParseAddr("2001::2"),
 		HWAddr: l.HWAddr,
 	})
@@ -72,7 +73,7 @@ func TestV6_AddReplace(t *testing.T) {
 	require.True(t, ok)
 
 	// Add dynamic leases.
-	dynLeases := []*Lease{{
+	dynLeases := []*dhcpsvc.Lease{{
 		IP:     netip.MustParseAddr("2001::1"),
 		HWAddr: net.HardwareAddr{0x11, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 	}, {
@@ -84,7 +85,7 @@ func TestV6_AddReplace(t *testing.T) {
 		s.addLease(l)
 	}
 
-	stLeases := []*Lease{{
+	stLeases := []*dhcpsvc.Lease{{
 		IP:     netip.MustParseAddr("2001::1"),
 		HWAddr: net.HardwareAddr{0x33, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 	}, {
@@ -126,7 +127,7 @@ func TestV6GetLease(t *testing.T) {
 		LinkLayerAddr: net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 	}
 
-	l := &Lease{
+	l := &dhcpsvc.Lease{
 		IP:     netip.MustParseAddr("2001::1"),
 		HWAddr: net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 	}
@@ -324,7 +325,7 @@ func TestV6_FindMACbyIP(t *testing.T) {
 	anotherMAC := net.HardwareAddr{0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB}
 
 	s := &v6Server{
-		leases: []*Lease{{
+		leases: []*dhcpsvc.Lease{{
 			Hostname: staticName,
 			HWAddr:   staticMAC,
 			IP:       staticIP,
@@ -337,7 +338,7 @@ func TestV6_FindMACbyIP(t *testing.T) {
 		}},
 	}
 
-	s.leases = []*Lease{{
+	s.leases = []*dhcpsvc.Lease{{
 		Hostname: staticName,
 		HWAddr:   staticMAC,
 		IP:       staticIP,

internal/dhcpsvc/config.go

@@ -43,7 +43,7 @@ func (conf *Config) Validate() (err error) {
 	case !conf.Enabled:
 		return nil
 	case conf.ICMPTimeout < 0:
-		return fmt.Errorf("icmp timeout %s must be non-negative", conf.ICMPTimeout)
+		return newMustErr("icmp timeout", "be non-negative", conf.ICMPTimeout)
 	}
 
 	err = netutil.ValidateDomainName(conf.LocalDomainName)
@@ -68,9 +68,9 @@ func (conf *Config) Validate() (err error) {
 	return nil
 }
 
-// mustBeErr returns an error that indicates that valName must be as must
+// newMustErr returns an error that indicates that valName must be as must
 // describes.
-func mustBeErr(valName, must string, val fmt.Stringer) (err error) {
+func newMustErr(valName, must string, val fmt.Stringer) (err error) {
 	return fmt.Errorf("%s %s must %s", valName, val, must)
 }
 

internal/dhcpsvc/dhcpsvc.go

@@ -10,13 +10,13 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/next/agh"
+	"golang.org/x/exp/slices"
 )
 
 // Lease is a DHCP lease.
 //
-// TODO(e.burkov):  Consider it to [agh], since it also may be needed in
+// TODO(e.burkov):  Consider moving it to [agh], since it also may be needed in
-// [websvc].  Also think of implementing iterating methods with appropriate
+// [websvc].
-// signatures.
 type Lease struct {
 	// IP is the IP address leased to the client.
 	IP netip.Addr
@@ -34,6 +34,21 @@ type Lease struct {
 	IsStatic bool
 }
 
+// Clone returns a deep copy of l.
+func (l *Lease) Clone() (clone *Lease) {
+	if l == nil {
+		return nil
+	}
+
+	return &Lease{
+		Expiry:   l.Expiry,
+		Hostname: l.Hostname,
+		HWAddr:   slices.Clone(l.HWAddr),
+		IP:       l.IP,
+		IsStatic: l.IsStatic,
+	}
+}
+
 type Interface interface {
 	agh.ServiceWithConfig[*Config]
 
@@ -57,6 +72,9 @@ type Interface interface {
 	IPByHost(host string) (ip netip.Addr)
 
 	// Leases returns all the active DHCP leases.
+	//
+	// TODO(e.burkov):  Consider implementing iterating methods with appropriate
+	// signatures instead of cloning the whole list.
 	Leases() (ls []*Lease)
 
 	// AddLease adds a new DHCP lease.  It returns an error if the lease is
@@ -91,6 +109,9 @@ func (Empty) Shutdown(_ context.Context) (err error) { return nil }
 // Config implements the [ServiceWithConfig] interface for Empty.
 func (Empty) Config() (conf *Config) { return nil }
 
+// type check
+var _ Interface = Empty{}
+
 // Enabled implements the [Interface] interface for Empty.
 func (Empty) Enabled() (ok bool) { return false }
 
@@ -103,9 +124,6 @@ func (Empty) MACByIP(_ netip.Addr) (mac net.HardwareAddr) { return nil }
 // IPByHost implements the [Interface] interface for Empty.
 func (Empty) IPByHost(_ string) (ip netip.Addr) { return netip.Addr{} }
 
-// type check
-var _ Interface = Empty{}
-
 // Leases implements the [Interface] interface for Empty.
 func (Empty) Leases() (leases []*Lease) { return nil }
 

internal/dhcpsvc/server.go

@@ -25,6 +25,9 @@ type DHCPServer struct {
 	// interfaces6 is the set of IPv6 interfaces sorted by interface name.
 	interfaces6 []*iface6
 
+	// leases is the set of active DHCP leases.
+	leases []*Lease
+
 	// icmpTimeout is the timeout for checking another DHCP server's presence.
 	icmpTimeout time.Duration
 }
@@ -75,3 +78,23 @@ func New(conf *Config) (srv *DHCPServer, err error) {
 		icmpTimeout: conf.ICMPTimeout,
 	}, nil
 }
+
+// type check
+//
+// TODO(e.burkov):  Uncomment when the [Interface] interface is implemented.
+// var _ Interface = (*DHCPServer)(nil)
+
+// Enabled implements the [Interface] interface for *DHCPServer.
+func (srv *DHCPServer) Enabled() (ok bool) {
+	return srv.enabled.Load()
+}
+
+// Leases implements the [Interface] interface for *DHCPServer.
+func (srv *DHCPServer) Leases() (leases []*Lease) {
+	leases = make([]*Lease, 0, len(srv.leases))
+	for _, lease := range srv.leases {
+		leases = append(leases, lease.Clone())
+	}
+
+	return leases
+}

internal/dhcpsvc/v4.go

@@ -45,15 +45,15 @@ func (conf *IPv4Config) validate() (err error) {
 	case !conf.Enabled:
 		return nil
 	case !conf.GatewayIP.Is4():
-		return mustBeErr("gateway ip", "be a valid ipv4", conf.GatewayIP)
+		return newMustErr("gateway ip", "be a valid ipv4", conf.GatewayIP)
 	case !conf.SubnetMask.Is4():
-		return mustBeErr("subnet mask", "be a valid ipv4 cidr mask", conf.SubnetMask)
+		return newMustErr("subnet mask", "be a valid ipv4 cidr mask", conf.SubnetMask)
 	case !conf.RangeStart.Is4():
-		return mustBeErr("range start", "be a valid ipv4", conf.RangeStart)
+		return newMustErr("range start", "be a valid ipv4", conf.RangeStart)
 	case !conf.RangeEnd.Is4():
-		return mustBeErr("range end", "be a valid ipv4", conf.RangeEnd)
+		return newMustErr("range end", "be a valid ipv4", conf.RangeEnd)
 	case conf.LeaseDuration <= 0:
-		return mustBeErr("lease duration", "be less than %d", conf.LeaseDuration)
+		return newMustErr("lease duration", "be less than %d", conf.LeaseDuration)
 	default:
 		return nil
 	}

internal/home/clients_internal_test.go

@@ -314,7 +314,7 @@ func TestClientsAddExisting(t *testing.T) {
 
 		clients.dhcp = dhcpServer
 
-		err = dhcpServer.AddStaticLease(&dhcpd.Lease{
+		err = dhcpServer.AddStaticLease(&dhcpsvc.Lease{
 			HWAddr:   net.HardwareAddr{0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA},
 			IP:       ip,
 			Hostname: "testhost",