Merge pull request #792 from EmilyShepherd/check-dhcp

Update Allocate method to reuse lease if present

plugins/ipam/dhcp/daemon.go

@@ -80,12 +80,20 @@ func (d *DHCP) Allocate(args *skel.CmdArgs, result *current.Result) error {
 	}
 
 	clientID := generateClientID(args.ContainerID, conf.Name, args.IfName)
-	hostNetns := d.hostNetnsPrefix + args.Netns
-	l, err := AcquireLease(clientID, hostNetns, args.IfName,
-		optsRequesting, optsProviding,
-		d.clientTimeout, d.clientResendMax, d.broadcast)
-	if err != nil {
-		return err
+
+	// If we already have an active lease for this clientID, do not create
+	// another one
+	l := d.getLease(clientID)
+	if l != nil {
+		l.Check()
+	} else {
+		hostNetns := d.hostNetnsPrefix + args.Netns
+		l, err = AcquireLease(clientID, hostNetns, args.IfName,
+			optsRequesting, optsProviding,
+			d.clientTimeout, d.clientResendMax, d.broadcast)
+		if err != nil {
+			return err
+		}
 	}
 
 	ipn, err := l.IPNet()

plugins/ipam/dhcp/lease.go

@@ -67,6 +67,7 @@ type DHCPLease struct {
 	broadcast     bool
 	stopping      uint32
 	stop          chan struct{}
+	check         chan struct{}
 	wg            sync.WaitGroup
 	// list of requesting and providing options and if they are necessary / their value
 	optsRequesting map[dhcp4.OptionCode]bool
@@ -150,6 +151,7 @@ func AcquireLease(
 	l := &DHCPLease{
 		clientID:       clientID,
 		stop:           make(chan struct{}),
+		check:          make(chan struct{}),
 		timeout:        timeout,
 		resendMax:      resendMax,
 		broadcast:      broadcast,
@@ -200,6 +202,10 @@ func (l *DHCPLease) Stop() {
 	l.wg.Wait()
 }
 
+func (l *DHCPLease) Check() {
+	l.check <- struct{}{}
+}
+
 func (l *DHCPLease) getOptionsWithClientId() dhcp4.Options {
 	opts := make(dhcp4.Options)
 	opts[dhcp4.OptionClientIdentifier] = []byte(l.clientID)
@@ -334,6 +340,9 @@ func (l *DHCPLease) maintain() {
 		select {
 		case <-time.After(sleepDur):
 
+		case <-l.check:
+			log.Printf("%v: Checking lease", l.clientID)
+
 		case <-l.stop:
 			if err := l.release(); err != nil {
 				log.Printf("%v: failed to release DHCP lease: %v", l.clientID, err)