ipam/dhcp: Add broadcast flag

Signed-off-by: Micah Hausler <hausler.m@gmail.com>

plugins/ipam/dhcp/client.go

@@ -1,3 +1,17 @@
+// Copyright 2021 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package main
 
 import (

plugins/ipam/dhcp/daemon.go

@@ -43,6 +43,7 @@ type DHCP struct {
 	leases          map[string]*DHCPLease
 	hostNetnsPrefix string
 	clientTimeout   time.Duration
+	broadcast       bool
 }
 
 func newDHCP(clientTimeout time.Duration) *DHCP {
@@ -66,7 +67,7 @@ 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, d.clientTimeout)
+	l, err := AcquireLease(clientID, hostNetns, args.IfName, d.clientTimeout, d.broadcast)
 	if err != nil {
 		return err
 	}
@@ -161,7 +162,7 @@ func getListener(socketPath string) (net.Listener, error) {
 
 func runDaemon(
 	pidfilePath, hostPrefix, socketPath string,
-	dhcpClientTimeout time.Duration,
+	dhcpClientTimeout time.Duration, broadcast bool,
 ) error {
 	// since other goroutines (on separate threads) will change namespaces,
 	// ensure the RPC server does not get scheduled onto those
@@ -184,6 +185,7 @@ func runDaemon(
 
 	dhcp := newDHCP(dhcpClientTimeout)
 	dhcp.hostNetnsPrefix = hostPrefix
+	dhcp.broadcast = broadcast
 	rpc.Register(dhcp)
 	rpc.HandleHTTP()
 	http.Serve(l, nil)

plugins/ipam/dhcp/lease.go

@@ -57,6 +57,7 @@ type DHCPLease struct {
 	rebindingTime time.Time
 	expireTime    time.Time
 	timeout       time.Duration
+	broadcast     bool
 	stopping      uint32
 	stop          chan struct{}
 	wg            sync.WaitGroup
@@ -67,13 +68,14 @@ type DHCPLease struct {
 // calling DHCPLease.Stop()
 func AcquireLease(
 	clientID, netns, ifName string,
-	timeout time.Duration,
+	timeout time.Duration, broadcast bool,
 ) (*DHCPLease, error) {
 	errCh := make(chan error, 1)
 	l := &DHCPLease{
-		clientID: clientID,
+		clientID:  clientID,
-		stop:     make(chan struct{}),
+		stop:      make(chan struct{}),
-		timeout:  timeout,
+		timeout:   timeout,
+		broadcast: broadcast,
 	}
 
 	log.Printf("%v: acquiring lease", clientID)
@@ -120,7 +122,7 @@ func (l *DHCPLease) Stop() {
 }
 
 func (l *DHCPLease) acquire() error {
-	c, err := newDHCPClient(l.link, l.clientID, l.timeout)
+	c, err := newDHCPClient(l.link, l.clientID, l.timeout, l.broadcast)
 	if err != nil {
 		return err
 	}
@@ -247,7 +249,7 @@ func (l *DHCPLease) downIface() {
 }
 
 func (l *DHCPLease) renew() error {
-	c, err := newDHCPClient(l.link, l.clientID, l.timeout)
+	c, err := newDHCPClient(l.link, l.clientID, l.timeout, l.broadcast)
 	if err != nil {
 		return err
 	}
@@ -278,7 +280,7 @@ func (l *DHCPLease) renew() error {
 func (l *DHCPLease) release() error {
 	log.Printf("%v: releasing lease", l.clientID)
 
-	c, err := newDHCPClient(l.link, l.clientID, l.timeout)
+	c, err := newDHCPClient(l.link, l.clientID, l.timeout, l.broadcast)
 	if err != nil {
 		return err
 	}
@@ -369,6 +371,7 @@ func backoffRetry(f func() (*dhcp4.Packet, error)) (*dhcp4.Packet, error) {
 func newDHCPClient(
 	link netlink.Link, clientID string,
 	timeout time.Duration,
+	broadcast bool,
 ) (*dhcp4client.Client, error) {
 	pktsock, err := dhcp4client.NewPacketSock(link.Attrs().Index)
 	if err != nil {
@@ -378,7 +381,7 @@ func newDHCPClient(
 	return dhcp4client.New(
 		dhcp4client.HardwareAddr(link.Attrs().HardwareAddr),
 		dhcp4client.Timeout(timeout),
-		dhcp4client.Broadcast(false),
+		dhcp4client.Broadcast(broadcast),
 		dhcp4client.Connection(pktsock),
 	)
 }

plugins/ipam/dhcp/main.go

@@ -38,11 +38,13 @@ func main() {
 		var pidfilePath string
 		var hostPrefix string
 		var socketPath string
+		var broadcast bool
 		var timeout time.Duration
 		daemonFlags := flag.NewFlagSet("daemon", flag.ExitOnError)
 		daemonFlags.StringVar(&pidfilePath, "pidfile", "", "optional path to write daemon PID to")
 		daemonFlags.StringVar(&hostPrefix, "hostprefix", "", "optional prefix to host root")
 		daemonFlags.StringVar(&socketPath, "socketpath", "", "optional dhcp server socketpath")
+		daemonFlags.BoolVar(&broadcast, "broadcast", false, "broadcast DHCP leases")
 		daemonFlags.DurationVar(&timeout, "timeout", 10*time.Second, "optional dhcp client timeout duration")
 		daemonFlags.Parse(os.Args[2:])
 
@@ -50,7 +52,7 @@ func main() {
 			socketPath = defaultSocketPath
 		}
 
-		if err := runDaemon(pidfilePath, hostPrefix, socketPath, timeout); err != nil {
+		if err := runDaemon(pidfilePath, hostPrefix, socketPath, timeout, broadcast); err != nil {
 			log.Printf(err.Error())
 			os.Exit(1)
 		}