110 lines
2.2 KiB
Go
110 lines
2.2 KiB
Go
// On-disk database for lease table
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package dhcpd
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import (
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"encoding/json"
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"io/ioutil"
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"net"
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"os"
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"time"
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"github.com/AdguardTeam/golibs/file"
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"github.com/AdguardTeam/golibs/log"
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"github.com/krolaw/dhcp4"
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)
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const dbFilename = "leases.db"
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type leaseJSON struct {
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HWAddr []byte `json:"mac"`
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IP []byte `json:"ip"`
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Hostname string `json:"host"`
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Expiry int64 `json:"exp"`
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}
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// Safe version of dhcp4.IPInRange()
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func ipInRange(start, stop, ip net.IP) bool {
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if len(start) != len(stop) ||
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len(start) != len(ip) {
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return false
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}
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return dhcp4.IPInRange(start, stop, ip)
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}
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// Load lease table from DB
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func (s *Server) dbLoad() {
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s.leases = nil
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s.IPpool = make(map[[4]byte]net.HardwareAddr)
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data, err := ioutil.ReadFile(dbFilename)
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if err != nil {
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if !os.IsNotExist(err) {
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log.Error("DHCP: can't read file %s: %v", dbFilename, err)
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}
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return
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}
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obj := []leaseJSON{}
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err = json.Unmarshal(data, &obj)
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if err != nil {
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log.Error("DHCP: invalid DB: %v", err)
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return
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}
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numLeases := len(obj)
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for i := range obj {
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if obj[i].Expiry != leaseExpireStatic &&
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!ipInRange(s.leaseStart, s.leaseStop, obj[i].IP) {
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log.Tracef("Skipping a lease with IP %s: not within current IP range", obj[i].IP)
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continue
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}
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lease := Lease{
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HWAddr: obj[i].HWAddr,
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IP: obj[i].IP,
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Hostname: obj[i].Hostname,
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Expiry: time.Unix(obj[i].Expiry, 0),
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}
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s.leases = append(s.leases, &lease)
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s.reserveIP(lease.IP, lease.HWAddr)
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}
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log.Info("DHCP: loaded %d leases from DB", numLeases)
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}
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// Store lease table in DB
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func (s *Server) dbStore() {
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var leases []leaseJSON
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for i := range s.leases {
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if s.leases[i].Expiry.Unix() == 0 {
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continue
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}
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lease := leaseJSON{
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HWAddr: s.leases[i].HWAddr,
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IP: s.leases[i].IP,
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Hostname: s.leases[i].Hostname,
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Expiry: s.leases[i].Expiry.Unix(),
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}
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leases = append(leases, lease)
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}
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data, err := json.Marshal(leases)
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if err != nil {
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log.Error("json.Marshal: %v", err)
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return
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}
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err = file.SafeWrite(dbFilename, data)
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if err != nil {
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log.Error("DHCP: can't store lease table on disk: %v filename: %s",
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err, dbFilename)
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return
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}
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log.Info("DHCP: stored %d leases in DB", len(leases))
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}
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