+ DHCP: On-disk database for lease table

2019-03-05 17:15:38 +03:00
parent a2e9d69452
commit 67014c40f7
3 changed files with 146 additions and 0 deletions
--- a/dhcpd/db.go
+++ b/dhcpd/db.go
@@ -0,0 +1,98 @@
+// On-disk database for lease table
+
+package dhcpd
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net"
+	"os"
+	"time"
+
+	"github.com/AdguardTeam/golibs/file"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/krolaw/dhcp4"
+)
+
+const dbFilename = "leases.db"
+
+type leaseJSON struct {
+	HWAddr   []byte `json:"mac"`
+	IP       []byte `json:"ip"`
+	Hostname string `json:"host"`
+	Expiry   int64  `json:"exp"`
+}
+
+// Load lease table from DB
+func (s *Server) dbLoad() {
+	data, err := ioutil.ReadFile(dbFilename)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			log.Error("DHCP: can't read file %s: %v", dbFilename, err)
+		}
+		return
+	}
+
+	obj := []leaseJSON{}
+	err = json.Unmarshal(data, &obj)
+	if err != nil {
+		log.Error("DHCP: invalid DB: %v", err)
+		return
+	}
+
+	s.leases = nil
+	s.IPpool = make(map[[4]byte]net.HardwareAddr)
+
+	numLeases := len(obj)
+	for i := range obj {
+
+		if !dhcp4.IPInRange(s.leaseStart, s.leaseStop, obj[i].IP) {
+			log.Tracef("Skipping a lease with IP %s: not within current IP range", obj[i].IP)
+			continue
+		}
+
+		lease := Lease{
+			HWAddr:   obj[i].HWAddr,
+			IP:       obj[i].IP,
+			Hostname: obj[i].Hostname,
+			Expiry:   time.Unix(obj[i].Expiry, 0),
+		}
+
+		s.leases = append(s.leases, &lease)
+
+		s.reserveIP(lease.IP, lease.HWAddr)
+	}
+	log.Info("DHCP: loaded %d leases from DB", numLeases)
+}
+
+// Store lease table in DB
+func (s *Server) dbStore() {
+	var leases []leaseJSON
+
+	for i := range s.leases {
+		if s.leases[i].Expiry.Unix() == 0 {
+			continue
+		}
+		lease := leaseJSON{
+			HWAddr:   s.leases[i].HWAddr,
+			IP:       s.leases[i].IP,
+			Hostname: s.leases[i].Hostname,
+			Expiry:   s.leases[i].Expiry.Unix(),
+		}
+		leases = append(leases, lease)
+	}
+
+	data, err := json.Marshal(leases)
+	if err != nil {
+		log.Error("json.Marshal: %v", err)
+		return
+	}
+
+	err = file.SafeWrite(dbFilename, data)
+	if err != nil {
+		log.Error("DHCP: can't store lease table on disk: %v  filename: %s",
+			err, dbFilename)
+		return
+	}
+	log.Info("DHCP: stored %d leases in DB", len(leases))
+}