AdGuardHome/internal/dhcpd/migrate.go

107 lines
2.1 KiB
Go

package dhcpd
import (
"encoding/json"
"net"
"net/netip"
"os"
"path/filepath"
"time"
"github.com/AdguardTeam/golibs/errors"
"github.com/AdguardTeam/golibs/log"
)
const (
// leaseExpireStatic is used to define the Expiry field for static
// leases.
//
// Deprecated: Remove it when migration of DHCP leases will be not needed.
leaseExpireStatic = 1
// dbFilename contains saved leases.
//
// Deprecated: Use dataFilename.
dbFilename = "leases.db"
)
// leaseJSON is the structure of stored lease.
//
// Deprecated: Use [Lease].
type leaseJSON struct {
HWAddr []byte `json:"mac"`
IP []byte `json:"ip"`
Hostname string `json:"host"`
Expiry int64 `json:"exp"`
}
func normalizeIP(ip net.IP) net.IP {
ip4 := ip.To4()
if ip4 != nil {
return ip4
}
return ip
}
// migrateDB migrates stored leases if necessary.
func migrateDB(conf *ServerConfig) (err error) {
defer func() { err = errors.Annotate(err, "migrating db: %w") }()
oldLeasesPath := filepath.Join(conf.WorkDir, dbFilename)
dataDirPath := filepath.Join(conf.DataDir, dataFilename)
file, err := os.Open(oldLeasesPath)
if errors.Is(err, os.ErrNotExist) {
// 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{}
err = json.NewDecoder(file).Decode(&ljs)
if err != nil {
// Don't wrap the error since it's informative enough as is.
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)
continue
}
lease := &Lease{
Expiry: time.Unix(lj.Expiry, 0),
Hostname: lj.Hostname,
HWAddr: lj.HWAddr,
IP: ip,
IsStatic: lj.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.
return err
}
return os.Remove(oldLeasesPath)
}