Merge pull request #39620 from svanharmelen/f-cloudstack-instances

Godeps/Godeps.json

@@ -826,6 +826,14 @@
 			"Rev": "71acacd42f85e5e82f70a55327789582a5200a90"
 		},
 		{
+			"ImportPath": "github.com/d2g/dhcp4",
+			"Rev": "a1d1b6c41b1ce8a71a5121a9cee31809c4707d9c"
+		},
+		{
+			"ImportPath": "github.com/d2g/dhcp4client",
+			"Rev": "6e570ed0a266b730a860ba1068090f683b2c213a"
+		},
+		{
 			"ImportPath": "github.com/davecgh/go-spew/spew",
 			"Comment": "v1.1.0-1-g782f496",
 			"Rev": "782f4967f2dc4564575ca782fe2d04090b5faca8"

pkg/cloudprovider/providers/cloudstack/BUILD

@@ -10,12 +10,23 @@ go_library(
     name = "go_default_library",
     srcs = [
         "cloudstack.go",
+        "cloudstack_instances.go",
         "cloudstack_loadbalancer.go",
-    ],
+        "metadata.go",
+        "metadata_other.go",
+    ] + select({
+        "@io_bazel_rules_go//go/platform:linux_amd64": [
+            "metadata_linux.go",
+        ],
+        "//conditions:default": [],
+    }),
     deps = [
         "//pkg/cloudprovider:go_default_library",
         "//pkg/controller:go_default_library",
+        "//vendor/github.com/d2g/dhcp4:go_default_library",
+        "//vendor/github.com/d2g/dhcp4client:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
+        "//vendor/github.com/kardianos/osext:go_default_library",
         "//vendor/github.com/xanzy/go-cloudstack/cloudstack:go_default_library",
         "//vendor/gopkg.in/gcfg.v1:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",

pkg/cloudprovider/providers/cloudstack/cloudstack.go

@@ -20,11 +20,13 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
+	"path/filepath"
 
 	"github.com/golang/glog"
+	"github.com/kardianos/osext"
 	"github.com/xanzy/go-cloudstack/cloudstack"
 	"gopkg.in/gcfg.v1"
-
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	"k8s.io/kubernetes/pkg/controller"
@@ -48,6 +50,7 @@ type CSConfig struct {
 // CSCloud is an implementation of Interface for CloudStack.
 type CSCloud struct {
 	client    *cloudstack.CloudStackClient
+	metadata  *metadata
 	projectID string // If non-"", all resources will be created within this project
 	zone      string
 }
@@ -64,15 +67,14 @@ func init() {
 }
 
 func readConfig(config io.Reader) (*CSConfig, error) {
+	cfg := &CSConfig{}
+
 	if config == nil {
-		err := fmt.Errorf("no cloud provider config given")
-		return nil, err
+		return cfg, nil
 	}
 
-	cfg := &CSConfig{}
 	if err := gcfg.ReadInto(cfg, config); err != nil {
-		glog.Errorf("Couldn't parse config: %v", err)
-		return nil, err
+		return nil, fmt.Errorf("could not parse cloud provider config: %v", err)
 	}
 
 	return cfg, nil
@@ -80,9 +82,42 @@ func readConfig(config io.Reader) (*CSConfig, error) {
 
 // newCSCloud creates a new instance of CSCloud.
 func newCSCloud(cfg *CSConfig) (*CSCloud, error) {
-	client := cloudstack.NewAsyncClient(cfg.Global.APIURL, cfg.Global.APIKey, cfg.Global.SecretKey, !cfg.Global.SSLNoVerify)
+	cs := &CSCloud{
+		projectID: cfg.Global.ProjectID,
+		zone:      cfg.Global.Zone,
+	}
+
+	exe, err := osext.Executable()
+	if err != nil {
+		return nil, fmt.Errorf("cloud not find the service executable: %v", err)
+	}
 
-	return &CSCloud{client, cfg.Global.ProjectID, cfg.Global.Zone}, nil
+	// When running the kubelet service it's fine to not specify a config file (or only a
+	// partial config file) as all needed info can be retrieved anonymously using metadata.
+	if filepath.Base(exe) == "kubelet" || filepath.Base(exe) == "kubelet.exe" {
+		// In CloudStack your metadata is always served by the DHCP server.
+		dhcpServer, err := findDHCPServer()
+		if err == nil {
+			glog.V(4).Infof("Found metadata server: %v", dhcpServer)
+			cs.metadata = &metadata{dhcpServer: dhcpServer, zone: cs.zone}
+		} else {
+			glog.Errorf("Error searching metadata server: %v", err)
+		}
+	}
+
+	if cfg.Global.APIURL != "" && cfg.Global.APIKey != "" && cfg.Global.SecretKey != "" {
+		cs.client = cloudstack.NewAsyncClient(cfg.Global.APIURL, cfg.Global.APIKey, cfg.Global.SecretKey, !cfg.Global.SSLNoVerify)
+	}
+
+	if cs.client == nil {
+		if cs.metadata != nil {
+			glog.V(2).Infof("No API URL, key and secret are provided, so only using metadata!")
+		} else {
+			return nil, errors.New("no cloud provider config given")
+		}
+	}
+
+	return cs, nil
 }
 
 // Initialize passes a Kubernetes clientBuilder interface to the cloud provider
@@ -90,26 +125,54 @@ func (cs *CSCloud) Initialize(clientBuilder controller.ControllerClientBuilder)
 
 // LoadBalancer returns an implementation of LoadBalancer for CloudStack.
 func (cs *CSCloud) LoadBalancer() (cloudprovider.LoadBalancer, bool) {
+	if cs.client == nil {
+		return nil, false
+	}
+
 	return cs, true
 }
 
 // Instances returns an implementation of Instances for CloudStack.
 func (cs *CSCloud) Instances() (cloudprovider.Instances, bool) {
-	return nil, false
+	if cs.metadata != nil {
+		return cs.metadata, true
+	}
+
+	if cs.client == nil {
+		return nil, false
+	}
+
+	return cs, true
 }
 
 // Zones returns an implementation of Zones for CloudStack.
 func (cs *CSCloud) Zones() (cloudprovider.Zones, bool) {
+	if cs.metadata != nil {
+		return cs.metadata, true
+	}
+
+	if cs.client == nil {
+		return nil, false
+	}
+
 	return cs, true
 }
 
 // Clusters returns an implementation of Clusters for CloudStack.
 func (cs *CSCloud) Clusters() (cloudprovider.Clusters, bool) {
+	if cs.client == nil {
+		return nil, false
+	}
+
 	return nil, false
 }
 
 // Routes returns an implementation of Routes for CloudStack.
 func (cs *CSCloud) Routes() (cloudprovider.Routes, bool) {
+	if cs.client == nil {
+		return nil, false
+	}
+
 	return nil, false
 }
 
@@ -130,20 +193,72 @@ func (cs *CSCloud) HasClusterID() bool {
 
 // GetZone returns the Zone containing the region that the program is running in.
 func (cs *CSCloud) GetZone() (cloudprovider.Zone, error) {
+	zone := cloudprovider.Zone{}
+
+	if cs.zone == "" {
+		hostname, err := os.Hostname()
+		if err != nil {
+			return zone, fmt.Errorf("failed to get hostname for retrieving the zone: %v", err)
+		}
+
+		instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(hostname)
+		if err != nil {
+			if count == 0 {
+				return zone, fmt.Errorf("could not find instance for retrieving the zone: %v", err)
+			}
+			return zone, fmt.Errorf("error getting instance for retrieving the zone: %v", err)
+		}
+
+		cs.zone = instance.Zonename
+	}
+
 	glog.V(2).Infof("Current zone is %v", cs.zone)
-	return cloudprovider.Zone{Region: cs.zone}, nil
+	zone.FailureDomain = cs.zone
+	zone.Region = cs.zone
+
+	return zone, nil
 }
 
-// GetZoneByProviderID implements Zones.GetZoneByProviderID
-// This is particularly useful in external cloud providers where the kubelet
-// does not initialize node data.
+// GetZoneByProviderID returns the Zone, found by using the provider ID.
 func (cs *CSCloud) GetZoneByProviderID(providerID string) (cloudprovider.Zone, error) {
-	return cloudprovider.Zone{}, errors.New("GetZoneByProviderID not implemented")
+	zone := cloudprovider.Zone{}
+
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByID(
+		providerID,
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return zone, fmt.Errorf("could not find node by ID: %v", providerID)
+		}
+		return zone, fmt.Errorf("error retrieving zone: %v", err)
+	}
+
+	glog.V(2).Infof("Current zone is %v", cs.zone)
+	zone.FailureDomain = instance.Zonename
+	zone.Region = instance.Zonename
+
+	return zone, nil
 }
 
-// GetZoneByNodeName implements Zones.GetZoneByNodeName
-// This is particularly useful in external cloud providers where the kubelet
-// does not initialize node data.
+// GetZoneByNodeName returns the Zone, found by using the node name.
 func (cs *CSCloud) GetZoneByNodeName(nodeName types.NodeName) (cloudprovider.Zone, error) {
-	return cloudprovider.Zone{}, errors.New("GetZoneByNodeName not imeplemented")
+	zone := cloudprovider.Zone{}
+
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(
+		string(nodeName),
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return zone, fmt.Errorf("could not find node: %v", nodeName)
+		}
+		return zone, fmt.Errorf("error retrieving zone: %v", err)
+	}
+
+	glog.V(2).Infof("Current zone is %v", cs.zone)
+	zone.FailureDomain = instance.Zonename
+	zone.Region = instance.Zonename
+
+	return zone, nil
 }

pkg/cloudprovider/providers/cloudstack/cloudstack_instances.go

+/*
+Copyright 2016 The Kubernetes 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 cloudstack
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/golang/glog"
+	"github.com/xanzy/go-cloudstack/cloudstack"
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/kubernetes/pkg/cloudprovider"
+)
+
+// NodeAddresses returns the addresses of the specified instance.
+func (cs *CSCloud) NodeAddresses(name types.NodeName) ([]v1.NodeAddress, error) {
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(
+		string(name),
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return nil, cloudprovider.InstanceNotFound
+		}
+		return nil, fmt.Errorf("error retrieving node addresses: %v", err)
+	}
+
+	return cs.nodeAddresses(instance)
+}
+
+// NodeAddressesByProviderID returns the addresses of the specified instance.
+func (cs *CSCloud) NodeAddressesByProviderID(providerID string) ([]v1.NodeAddress, error) {
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByID(
+		providerID,
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return nil, cloudprovider.InstanceNotFound
+		}
+		return nil, fmt.Errorf("error retrieving node addresses: %v", err)
+	}
+
+	return cs.nodeAddresses(instance)
+}
+
+func (cs *CSCloud) nodeAddresses(instance *cloudstack.VirtualMachine) ([]v1.NodeAddress, error) {
+	if len(instance.Nic) == 0 {
+		return nil, errors.New("instance does not have an internal IP")
+	}
+
+	addresses := []v1.NodeAddress{
+		{Type: v1.NodeInternalIP, Address: instance.Nic[0].Ipaddress},
+	}
+
+	if instance.Publicip != "" {
+		addresses = append(addresses, v1.NodeAddress{Type: v1.NodeExternalIP, Address: instance.Publicip})
+	} else {
+		// Since there is no sane way to determine the external IP if the host isn't
+		// using static NAT, we will just fire a log message and omit the external IP.
+		glog.V(4).Infof("Could not determine the public IP of host %v (%v)", instance.Name, instance.Id)
+	}
+
+	return addresses, nil
+}
+
+// ExternalID returns the cloud provider ID of the specified instance (deprecated).
+func (cs *CSCloud) ExternalID(name types.NodeName) (string, error) {
+	return cs.InstanceID(name)
+}
+
+// InstanceID returns the cloud provider ID of the specified instance.
+func (cs *CSCloud) InstanceID(name types.NodeName) (string, error) {
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(
+		string(name),
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return "", cloudprovider.InstanceNotFound
+		}
+		return "", fmt.Errorf("error retrieving instance ID: %v", err)
+	}
+
+	return instance.Id, nil
+}
+
+// InstanceType returns the type of the specified instance.
+func (cs *CSCloud) InstanceType(name types.NodeName) (string, error) {
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(
+		string(name),
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return "", cloudprovider.InstanceNotFound
+		}
+		return "", fmt.Errorf("error retrieving instance type: %v", err)
+	}
+
+	return instance.Serviceofferingname, nil
+}
+
+// InstanceTypeByProviderID returns the type of the specified instance.
+func (cs *CSCloud) InstanceTypeByProviderID(providerID string) (string, error) {
+	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByID(
+		providerID,
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return "", cloudprovider.InstanceNotFound
+		}
+		return "", fmt.Errorf("error retrieving instance type: %v", err)
+	}
+
+	return instance.Serviceofferingname, nil
+}
+
+// AddSSHKeyToAllInstances is currently not implemented.
+func (cs *CSCloud) AddSSHKeyToAllInstances(user string, keyData []byte) error {
+	return errors.New("AddSSHKeyToAllInstances not implemented")
+}
+
+// CurrentNodeName returns the name of the node we are currently running on.
+func (cs *CSCloud) CurrentNodeName(hostname string) (types.NodeName, error) {
+	return types.NodeName(hostname), nil
+}
+
+// InstanceExistsByProviderID returns if the instance still exists.
+func (cs *CSCloud) InstanceExistsByProviderID(providerID string) (bool, error) {
+	_, count, err := cs.client.VirtualMachine.GetVirtualMachineByID(
+		providerID,
+		cloudstack.WithProject(cs.projectID),
+	)
+	if err != nil {
+		if count == 0 {
+			return false, nil
+		}
+		return false, fmt.Errorf("error retrieving instance: %v", err)
+	}
+
+	return true, nil
+}

pkg/cloudprovider/providers/cloudstack/cloudstack_test.go

@@ -30,8 +30,8 @@ const testClusterName = "testCluster"
 
 func TestReadConfig(t *testing.T) {
 	_, err := readConfig(nil)
-	if err == nil {
-		t.Errorf("Should fail when no config is provided: %v", err)
+	if err != nil {
+		t.Fatalf("Should not return an error when no config is provided: %v", err)
 	}
 
 	cfg, err := readConfig(strings.NewReader(`
@@ -41,7 +41,6 @@ func TestReadConfig(t *testing.T) {
  secret-key			= a-valid-secret-key
  ssl-no-verify	= true
  project-id			= a-valid-project-id
- zone						= a-valid-zone
  `))
 	if err != nil {
 		t.Fatalf("Should succeed when a valid config is provided: %v", err)
@@ -59,9 +58,6 @@ func TestReadConfig(t *testing.T) {
 	if !cfg.Global.SSLNoVerify {
 		t.Errorf("incorrect ssl-no-verify: %t", cfg.Global.SSLNoVerify)
 	}
-	if cfg.Global.Zone != "a-valid-zone" {
-		t.Errorf("incorrect zone: %s", cfg.Global.Zone)
-	}
 }
 
 // This allows acceptance testing against an existing CloudStack environment.
@@ -72,7 +68,6 @@ func configFromEnv() (*CSConfig, bool) {
 	cfg.Global.APIKey = os.Getenv("CS_API_KEY")
 	cfg.Global.SecretKey = os.Getenv("CS_SECRET_KEY")
 	cfg.Global.ProjectID = os.Getenv("CS_PROJECT_ID")
-	cfg.Global.Zone = os.Getenv("CS_ZONE")
 
 	// It is save to ignore the error here. If the input cannot be parsed SSLNoVerify
 	// will still be a bool with its zero value (false) which is the expected default.
@@ -120,23 +115,3 @@ func TestLoadBalancer(t *testing.T) {
 		t.Fatalf("GetLoadBalancer(\"noexist\") returned exists")
 	}
 }
-
-func TestZones(t *testing.T) {
-	cs := &CSCloud{
-		zone: "myRegion",
-	}
-
-	z, ok := cs.Zones()
-	if !ok {
-		t.Fatalf("Zones() returned false")
-	}
-
-	zone, err := z.GetZone()
-	if err != nil {
-		t.Fatalf("GetZone() returned error: %s", err)
-	}
-
-	if zone.Region != "myRegion" {
-		t.Fatalf("GetZone() returned wrong region (%s)", zone.Region)
-	}
-}

pkg/cloudprovider/providers/cloudstack/metadata.go

+/*
+Copyright 2016 The Kubernetes 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 cloudstack
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+
+	"github.com/d2g/dhcp4"
+	"github.com/golang/glog"
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/kubernetes/pkg/cloudprovider"
+)
+
+type metadata struct {
+	dhcpServer string
+	zone       string
+}
+
+type metadataType string
+
+const (
+	metadataTypeExternalIP   metadataType = "public-ipv4"
+	metadataTypeInternalIP   metadataType = "local-ipv4"
+	metadataTypeInstanceID   metadataType = "instance-id"
+	metadataTypeInstanceType metadataType = "service-offering"
+	metadataTypeZone         metadataType = "availability-zone"
+)
+
+// NodeAddresses returns the addresses of the specified instance.
+func (m *metadata) NodeAddresses(name types.NodeName) ([]v1.NodeAddress, error) {
+	externalIP, err := m.get(metadataTypeExternalIP)
+	if err != nil {
+		return nil, fmt.Errorf("could not get external IP: %v", err)
+	}
+
+	internalIP, err := m.get(metadataTypeInternalIP)
+	if err != nil {
+		return nil, fmt.Errorf("could not get internal IP: %v", err)
+	}
+
+	return []v1.NodeAddress{
+		{Type: v1.NodeExternalIP, Address: externalIP},
+		{Type: v1.NodeInternalIP, Address: internalIP},
+	}, nil
+}
+
+// NodeAddressesByProviderID returns the addresses of the specified instance.
+func (m *metadata) NodeAddressesByProviderID(providerID string) ([]v1.NodeAddress, error) {
+	return nil, errors.New("NodeAddressesByProviderID not implemented")
+}
+
+// ExternalID returns the cloud provider ID of the specified instance (deprecated).
+func (m *metadata) ExternalID(name types.NodeName) (string, error) {
+	return m.InstanceID(name)
+}
+
+// InstanceID returns the cloud provider ID of the specified instance.
+func (m *metadata) InstanceID(name types.NodeName) (string, error) {
+	instanceID, err := m.get(metadataTypeInstanceID)
+	if err != nil {
+		return "", fmt.Errorf("could not get instance ID: %v", err)
+	}
+
+	zone, err := m.get(metadataTypeZone)
+	if err != nil {
+		return "", fmt.Errorf("could not get zone: %v", err)
+	}
+
+	return "/" + zone + "/" + instanceID, nil
+}
+
+// InstanceType returns the type of the specified instance.
+func (m *metadata) InstanceType(name types.NodeName) (string, error) {
+	instanceType, err := m.get(metadataTypeInstanceType)
+	if err == nil {
+		return "", fmt.Errorf("could not get instance type: %v", err)
+	}
+
+	return instanceType, nil
+}
+
+// InstanceTypeByProviderID returns the type of the specified instance.
+func (m *metadata) InstanceTypeByProviderID(providerID string) (string, error) {
+	return "", errors.New("InstanceTypeByProviderID not implemented")
+}
+
+// AddSSHKeyToAllInstances is currently not implemented.
+func (m *metadata) AddSSHKeyToAllInstances(user string, keyData []byte) error {
+	return errors.New("AddSSHKeyToAllInstances not implemented")
+}
+
+// CurrentNodeName returns the name of the node we are currently running on.
+func (m *metadata) CurrentNodeName(hostname string) (types.NodeName, error) {
+	return types.NodeName(hostname), nil
+}
+
+// InstanceExistsByProviderID returns if the instance still exists.
+func (m *metadata) InstanceExistsByProviderID(providerID string) (bool, error) {
+	return false, errors.New("InstanceExistsByProviderID not implemented")
+}
+
+// GetZone returns the Zone containing the region that the program is running in.
+func (m *metadata) GetZone() (cloudprovider.Zone, error) {
+	zone := cloudprovider.Zone{}
+
+	if m.zone == "" {
+		zoneName, err := m.get(metadataTypeZone)
+		if err != nil {
+			return zone, fmt.Errorf("could not get zone: %v", err)
+		}
+
+		m.zone = zoneName
+	}
+
+	glog.V(2).Infof("Current zone is %v", zone)
+	zone.FailureDomain = m.zone
+	zone.Region = m.zone
+
+	return zone, nil
+}
+
+// GetZoneByProviderID returns the Zone, found by using the provider ID.
+func (m *metadata) GetZoneByProviderID(providerID string) (cloudprovider.Zone, error) {
+	return cloudprovider.Zone{}, errors.New("GetZoneByProviderID not implemented")
+}
+
+// GetZoneByNodeName returns the Zone, found by using the node name.
+func (m *metadata) GetZoneByNodeName(nodeName types.NodeName) (cloudprovider.Zone, error) {
+	return cloudprovider.Zone{}, errors.New("GetZoneByNodeName not implemented")
+}
+
+func (m *metadata) get(mdType metadataType) (string, error) {
+	url := fmt.Sprintf("http://%s/latest/meta-data/%s", m.dhcpServer, mdType)
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", fmt.Errorf("error reading metadata: %v", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("unexpected HTTP status: %d", resp.StatusCode)
+	}
+
+	data, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("error reading response body: %d", resp.StatusCode)
+	}
+
+	return string(data), nil
+}
+
+func findDHCPServer() (string, error) {
+	nics, err := net.Interfaces()
+	if err != nil {
+		return "", fmt.Errorf("could not get interfaces: %v", err)
+	}
+
+	for _, nic := range nics {
+		if nic.Flags&net.FlagUp == 1 && nic.Flags&net.FlagLoopback == 0 && nic.Flags&net.FlagPointToPoint == 0 {
+			addrs, err := nic.Addrs()
+			if err != nil {
+				return "", fmt.Errorf("error reading IP addresses from interface %v: %v", nic.Name, err)
+			}
+
+			if addrs != nil {
+				client, err := newDHCPClient(&nic)
+				if err != nil {
+					return "", fmt.Errorf("error creating new DHCP client: %v", err)
+				}
+
+				discoverPacket, err := client.SendDiscoverPacket()
+				if err != nil {
+					return "", fmt.Errorf("error sending DHCP discover package: %v", err)
+				}
+
+				offerPacket, err := client.GetOffer(&discoverPacket)
+				if err != nil {
+					return "", fmt.Errorf("error recieving DHCP offer package: %v", err)
+				}
+
+				offerPacketOptions := offerPacket.ParseOptions()
+
+				if ipaddr, ok := offerPacketOptions[dhcp4.OptionServerIdentifier]; ok {
+					return net.IP(ipaddr).String(), nil
+				}
+			}
+		}
+	}
+
+	return "", errors.New("no server found")
+}

pkg/cloudprovider/providers/cloudstack/metadata_linux.go

+// +build linux
+
+/*
+Copyright 2016 The Kubernetes 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 cloudstack
+
+import (
+	"net"
+	"time"
+
+	"github.com/d2g/dhcp4client"
+)
+
+func newDHCPClient(nic *net.Interface) (*dhcp4client.Client, error) {
+	pktsock, err := dhcp4client.NewPacketSock(nic.Index)
+	if err != nil {
+		return nil, err
+	}
+
+	return dhcp4client.New(
+		dhcp4client.HardwareAddr(nic.HardwareAddr),
+		dhcp4client.Timeout(2*time.Second),
+		dhcp4client.Broadcast(false),
+		dhcp4client.Connection(pktsock),
+	)
+}

pkg/cloudprovider/providers/cloudstack/metadata_other.go

+// +build !linux
+
+/*
+Copyright 2016 The Kubernetes 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 cloudstack
+
+import (
+	"net"
+	"time"
+
+	"github.com/d2g/dhcp4client"
+)
+
+func newDHCPClient(nic *net.Interface) (*dhcp4client.Client, error) {
+	inetsock, err := dhcp4client.NewInetSock()
+	if err != nil {
+		return nil, err
+	}
+
+	return dhcp4client.New(
+		dhcp4client.HardwareAddr(nic.HardwareAddr),
+		dhcp4client.Timeout(2*time.Second),
+		dhcp4client.Broadcast(false),
+		dhcp4client.Connection(inetsock),
+	)
+}

vendor/BUILD

@@ -119,6 +119,8 @@ filegroup(
         "//vendor/github.com/coreos/pkg/timeutil:all-srcs",
         "//vendor/github.com/coreos/rkt/api/v1alpha:all-srcs",
         "//vendor/github.com/cpuguy83/go-md2man/md2man:all-srcs",
+        "//vendor/github.com/d2g/dhcp4:all-srcs",
+        "//vendor/github.com/d2g/dhcp4client:all-srcs",
         "//vendor/github.com/davecgh/go-spew/spew:all-srcs",
         "//vendor/github.com/daviddengcn/go-colortext:all-srcs",
         "//vendor/github.com/dgrijalva/jwt-go:all-srcs",

vendor/github.com/d2g/dhcp4/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "constants.go",
+        "helpers.go",
+        "option.go",
+        "packet.go",
+    ],
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

vendor/github.com/d2g/dhcp4/LICENSE

+Copyright (c) 2013 Skagerrak Software Limited. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Skagerrak Software Limited nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\ No newline at end of file

vendor/github.com/d2g/dhcp4/README.md

+# DHCP4 - A DHCP library written in Go.
+
+Warning: This library is still being developed.  Function calls will change.
+
+I've removed Server Functionality, for me this project supports the underlying DHCP format not the implementation.

vendor/github.com/d2g/dhcp4/constants.go

+package dhcp4
+
+// OpCodes
+const (
+	BootRequest OpCode = 1 // From Client
+	BootReply   OpCode = 2 // From Server
+)
+
+// DHCP Message Type 53
+const (
+	Discover MessageType = 1 // Broadcast Packet From Client - Can I have an IP?
+	Offer    MessageType = 2 // Broadcast From Server - Here's an IP
+	Request  MessageType = 3 // Broadcast From Client - I'll take that IP (Also start for renewals)
+	Decline  MessageType = 4 // Broadcast From Client - Sorry I can't use that IP
+	ACK      MessageType = 5 // From Server, Yes you can have that IP
+	NAK      MessageType = 6 // From Server, No you cannot have that IP
+	Release  MessageType = 7 // From Client, I don't need that IP anymore
+	Inform   MessageType = 8 // From Client, I have this IP and there's nothing you can do about it
+)
+
+// DHCP Options
+const (
+	End                          OptionCode = 255
+	Pad                          OptionCode = 0
+	OptionSubnetMask             OptionCode = 1
+	OptionTimeOffset             OptionCode = 2
+	OptionRouter                 OptionCode = 3
+	OptionTimeServer             OptionCode = 4
+	OptionNameServer             OptionCode = 5
+	OptionDomainNameServer       OptionCode = 6
+	OptionLogServer              OptionCode = 7
+	OptionCookieServer           OptionCode = 8
+	OptionLPRServer              OptionCode = 9
+	OptionImpressServer          OptionCode = 10
+	OptionResourceLocationServer OptionCode = 11
+	OptionHostName               OptionCode = 12
+	OptionBootFileSize           OptionCode = 13
+	OptionMeritDumpFile          OptionCode = 14
+	OptionDomainName             OptionCode = 15
+	OptionSwapServer             OptionCode = 16
+	OptionRootPath               OptionCode = 17
+	OptionExtensionsPath         OptionCode = 18
+
+	// IP Layer Parameters per Host
+	OptionIPForwardingEnableDisable          OptionCode = 19
+	OptionNonLocalSourceRoutingEnableDisable OptionCode = 20
+	OptionPolicyFilter                       OptionCode = 21
+	OptionMaximumDatagramReassemblySize      OptionCode = 22
+	OptionDefaultIPTimeToLive                OptionCode = 23
+	OptionPathMTUAgingTimeout                OptionCode = 24
+	OptionPathMTUPlateauTable                OptionCode = 25
+
+	// IP Layer Parameters per Interface
+	OptionInterfaceMTU              OptionCode = 26
+	OptionAllSubnetsAreLocal        OptionCode = 27
+	OptionBroadcastAddress          OptionCode = 28
+	OptionPerformMaskDiscovery      OptionCode = 29
+	OptionMaskSupplier              OptionCode = 30
+	OptionPerformRouterDiscovery    OptionCode = 31
+	OptionRouterSolicitationAddress OptionCode = 32
+	OptionStaticRoute               OptionCode = 33
+
+	// Link Layer Parameters per Interface
+	OptionTrailerEncapsulation  OptionCode = 34
+	OptionARPCacheTimeout       OptionCode = 35
+	OptionEthernetEncapsulation OptionCode = 36
+
+	// TCP Parameters
+	OptionTCPDefaultTTL        OptionCode = 37
+	OptionTCPKeepaliveInterval OptionCode = 38
+	OptionTCPKeepaliveGarbage  OptionCode = 39
+
+	// Application and Service Parameters
+	OptionNetworkInformationServiceDomain            OptionCode = 40
+	OptionNetworkInformationServers                  OptionCode = 41
+	OptionNetworkTimeProtocolServers                 OptionCode = 42
+	OptionVendorSpecificInformation                  OptionCode = 43
+	OptionNetBIOSOverTCPIPNameServer                 OptionCode = 44
+	OptionNetBIOSOverTCPIPDatagramDistributionServer OptionCode = 45
+	OptionNetBIOSOverTCPIPNodeType                   OptionCode = 46
+	OptionNetBIOSOverTCPIPScope                      OptionCode = 47
+	OptionXWindowSystemFontServer                    OptionCode = 48
+	OptionXWindowSystemDisplayManager                OptionCode = 49
+	OptionNetworkInformationServicePlusDomain        OptionCode = 64
+	OptionNetworkInformationServicePlusServers       OptionCode = 65
+	OptionMobileIPHomeAgent                          OptionCode = 68
+	OptionSimpleMailTransportProtocol                OptionCode = 69
+	OptionPostOfficeProtocolServer                   OptionCode = 70
+	OptionNetworkNewsTransportProtocol               OptionCode = 71
+	OptionDefaultWorldWideWebServer                  OptionCode = 72
+	OptionDefaultFingerServer                        OptionCode = 73
+	OptionDefaultInternetRelayChatServer             OptionCode = 74
+	OptionStreetTalkServer                           OptionCode = 75
+	OptionStreetTalkDirectoryAssistance              OptionCode = 76
+
+	// DHCP Extensions
+	OptionRequestedIPAddress     OptionCode = 50
+	OptionIPAddressLeaseTime     OptionCode = 51
+	OptionOverload               OptionCode = 52
+	OptionDHCPMessageType        OptionCode = 53
+	OptionServerIdentifier       OptionCode = 54
+	OptionParameterRequestList   OptionCode = 55
+	OptionMessage                OptionCode = 56
+	OptionMaximumDHCPMessageSize OptionCode = 57
+	OptionRenewalTimeValue       OptionCode = 58
+	OptionRebindingTimeValue     OptionCode = 59
+	OptionVendorClassIdentifier  OptionCode = 60
+	OptionClientIdentifier       OptionCode = 61
+
+	OptionTFTPServerName OptionCode = 66
+	OptionBootFileName   OptionCode = 67
+
+	OptionUserClass OptionCode = 77
+
+	OptionClientArchitecture OptionCode = 93
+
+	OptionTZPOSIXString    OptionCode = 100
+	OptionTZDatabaseString OptionCode = 101
+
+	OptionClasslessRouteFormat OptionCode = 121
+)

vendor/github.com/d2g/dhcp4/helpers.go

+package dhcp4
+
+import (
+	"encoding/binary"
+	"net"
+	"time"
+)
+
+// IPRange returns how many ips in the ip range from start to stop (inclusive)
+func IPRange(start, stop net.IP) int {
+	//return int(Uint([]byte(stop))-Uint([]byte(start))) + 1
+	return int(binary.BigEndian.Uint32(stop.To4())) - int(binary.BigEndian.Uint32(start.To4())) + 1
+}
+
+// IPAdd returns a copy of start + add.
+// IPAdd(net.IP{192,168,1,1},30) returns net.IP{192.168.1.31}
+func IPAdd(start net.IP, add int) net.IP { // IPv4 only
+	start = start.To4()
+	//v := Uvarint([]byte(start))
+	result := make(net.IP, 4)
+	binary.BigEndian.PutUint32(result, binary.BigEndian.Uint32(start)+uint32(add))
+	//PutUint([]byte(result), v+uint64(add))
+	return result
+}
+
+// IPLess returns where IP a is less than IP b.
+func IPLess(a, b net.IP) bool {
+	b = b.To4()
+	for i, ai := range a.To4() {
+		if ai != b[i] {
+			return ai < b[i]
+		}
+	}
+	return false
+}
+
+// IPInRange returns true if ip is between (inclusive) start and stop.
+func IPInRange(start, stop, ip net.IP) bool {
+	return !(IPLess(ip, start) || IPLess(stop, ip))
+}
+
+// OptionsLeaseTime - converts a time.Duration to a 4 byte slice, compatible
+// with OptionIPAddressLeaseTime.
+func OptionsLeaseTime(d time.Duration) []byte {
+	leaseBytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(leaseBytes, uint32(d/time.Second))
+	//PutUvarint(leaseBytes, uint64(d/time.Second))
+	return leaseBytes
+}
+
+// JoinIPs returns a byte slice of IP addresses, one immediately after the other
+// This may be useful for creating multiple IP options such as OptionRouter.
+func JoinIPs(ips []net.IP) (b []byte) {
+	for _, v := range ips {
+		b = append(b, v.To4()...)
+	}
+	return
+}

vendor/github.com/d2g/dhcp4/option.go

+package dhcp4
+
+type OptionCode byte
+
+type Option struct {
+	Code  OptionCode
+	Value []byte
+}
+
+// Map of DHCP options
+type Options map[OptionCode][]byte
+
+// SelectOrderOrAll has same functionality as SelectOrder, except if the order
+// param is nil, whereby all options are added (in arbitrary order).
+func (o Options) SelectOrderOrAll(order []byte) []Option {
+	if order == nil {
+		opts := make([]Option, 0, len(o))
+		for i, v := range o {
+			opts = append(opts, Option{Code: i, Value: v})
+		}
+		return opts
+	}
+	return o.SelectOrder(order)
+}
+
+// SelectOrder returns a slice of options ordered and selected by a byte array
+// usually defined by OptionParameterRequestList.  This result is expected to be
+// used in ReplyPacket()'s []Option parameter.
+func (o Options) SelectOrder(order []byte) []Option {
+	opts := make([]Option, 0, len(order))
+	for _, v := range order {
+		if data, ok := o[OptionCode(v)]; ok {
+			opts = append(opts, Option{Code: OptionCode(v), Value: data})
+		}
+	}
+	return opts
+}
+
+type OpCode byte
+type MessageType byte // Option 53

vendor/github.com/d2g/dhcp4/packet.go

+package dhcp4
+
+import (
+	"net"
+	"time"
+)
+
+// A DHCP packet
+type Packet []byte
+
+func (p Packet) OpCode() OpCode { return OpCode(p[0]) }
+func (p Packet) HType() byte    { return p[1] }
+func (p Packet) HLen() byte     { return p[2] }
+func (p Packet) Hops() byte     { return p[3] }
+func (p Packet) XId() []byte    { return p[4:8] }
+func (p Packet) Secs() []byte   { return p[8:10] } // Never Used?
+func (p Packet) Flags() []byte  { return p[10:12] }
+func (p Packet) CIAddr() net.IP { return net.IP(p[12:16]) }
+func (p Packet) YIAddr() net.IP { return net.IP(p[16:20]) }
+func (p Packet) SIAddr() net.IP { return net.IP(p[20:24]) }
+func (p Packet) GIAddr() net.IP { return net.IP(p[24:28]) }
+func (p Packet) CHAddr() net.HardwareAddr {
+	hLen := p.HLen()
+	if hLen > 16 { // Prevent chaddr exceeding p boundary
+		hLen = 16
+	}
+	return net.HardwareAddr(p[28 : 28+hLen]) // max endPos 44
+}
+
+// 192 bytes of zeros BOOTP legacy
+func (p Packet) Cookie() []byte { return p[236:240] }
+func (p Packet) Options() []byte {
+	if len(p) > 240 {
+		return p[240:]
+	}
+	return nil
+}
+
+func (p Packet) Broadcast() bool { return p.Flags()[0] > 127 }
+
+func (p Packet) SetBroadcast(broadcast bool) {
+	if p.Broadcast() != broadcast {
+		p.Flags()[0] ^= 128
+	}
+}
+
+func (p Packet) SetOpCode(c OpCode) { p[0] = byte(c) }
+func (p Packet) SetCHAddr(a net.HardwareAddr) {
+	copy(p[28:44], a)
+	p[2] = byte(len(a))
+}
+func (p Packet) SetHType(hType byte)     { p[1] = hType }
+func (p Packet) SetCookie(cookie []byte) { copy(p.Cookie(), cookie) }
+func (p Packet) SetHops(hops byte)       { p[3] = hops }
+func (p Packet) SetXId(xId []byte)       { copy(p.XId(), xId) }
+func (p Packet) SetSecs(secs []byte)     { copy(p.Secs(), secs) }
+func (p Packet) SetFlags(flags []byte)   { copy(p.Flags(), flags) }
+func (p Packet) SetCIAddr(ip net.IP)     { copy(p.CIAddr(), ip.To4()) }
+func (p Packet) SetYIAddr(ip net.IP)     { copy(p.YIAddr(), ip.To4()) }
+func (p Packet) SetSIAddr(ip net.IP)     { copy(p.SIAddr(), ip.To4()) }
+func (p Packet) SetGIAddr(ip net.IP)     { copy(p.GIAddr(), ip.To4()) }
+
+// Parses the packet's options into an Options map
+func (p Packet) ParseOptions() Options {
+	opts := p.Options()
+	options := make(Options, 10)
+	for len(opts) >= 2 && OptionCode(opts[0]) != End {
+		if OptionCode(opts[0]) == Pad {
+			opts = opts[1:]
+			continue
+		}
+		size := int(opts[1])
+		if len(opts) < 2+size {
+			break
+		}
+		options[OptionCode(opts[0])] = opts[2 : 2+size]
+		opts = opts[2+size:]
+	}
+	return options
+}
+
+func NewPacket(opCode OpCode) Packet {
+	p := make(Packet, 241)
+	p.SetOpCode(opCode)
+	p.SetHType(1) // Ethernet
+	p.SetCookie([]byte{99, 130, 83, 99})
+	p[240] = byte(End)
+	return p
+}
+
+// Appends a DHCP option to the end of a packet
+func (p *Packet) AddOption(o OptionCode, value []byte) {
+	*p = append((*p)[:len(*p)-1], []byte{byte(o), byte(len(value))}...) // Strip off End, Add OptionCode and Length
+	*p = append(*p, value...)                                           // Add Option Value
+	*p = append(*p, byte(End))                                          // Add on new End
+}
+
+// Removes all options from packet.
+func (p *Packet) StripOptions() {
+	*p = append((*p)[:240], byte(End))
+}
+
+// Creates a request packet that a Client would send to a server.
+func RequestPacket(mt MessageType, chAddr net.HardwareAddr, cIAddr net.IP, xId []byte, broadcast bool, options []Option) Packet {
+	p := NewPacket(BootRequest)
+	p.SetCHAddr(chAddr)
+	p.SetXId(xId)
+	if cIAddr != nil {
+		p.SetCIAddr(cIAddr)
+	}
+	p.SetBroadcast(broadcast)
+	p.AddOption(OptionDHCPMessageType, []byte{byte(mt)})
+	for _, o := range options {
+		p.AddOption(o.Code, o.Value)
+	}
+	p.PadToMinSize()
+	return p
+}
+
+// ReplyPacket creates a reply packet that a Server would send to a client.
+// It uses the req Packet param to copy across common/necessary fields to
+// associate the reply the request.
+func ReplyPacket(req Packet, mt MessageType, serverId, yIAddr net.IP, leaseDuration time.Duration, options []Option) Packet {
+	p := NewPacket(BootReply)
+	p.SetXId(req.XId())
+	p.SetFlags(req.Flags())
+	p.SetYIAddr(yIAddr)
+	p.SetGIAddr(req.GIAddr())
+	p.SetCHAddr(req.CHAddr())
+	p.AddOption(OptionDHCPMessageType, []byte{byte(mt)})
+	p.AddOption(OptionServerIdentifier, []byte(serverId))
+	if leaseDuration > 0 {
+		p.AddOption(OptionIPAddressLeaseTime, OptionsLeaseTime(leaseDuration))
+	}
+	for _, o := range options {
+		p.AddOption(o.Code, o.Value)
+	}
+	p.PadToMinSize()
+	return p
+}
+
+// PadToMinSize pads a packet so that when sent over UDP, the entire packet,
+// is 300 bytes (BOOTP min), to be compatible with really old devices.
+var padder [272]byte
+
+func (p *Packet) PadToMinSize() {
+	if n := len(*p); n < 272 {
+		*p = append(*p, padder[:272-n]...)
+	}
+}

vendor/github.com/d2g/dhcp4client/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "client.go",
+        "generatexid.go",
+        "inetsock.go",
+    ] + select({
+        "@io_bazel_rules_go//go/platform:linux_amd64": [
+            "pktsock_linux.go",
+        ],
+        "//conditions:default": [],
+    }),
+    visibility = ["//visibility:public"],
+    deps = [
+        "//vendor/github.com/d2g/dhcp4:go_default_library",
+    ] + select({
+        "@io_bazel_rules_go//go/platform:linux_amd64": [
+            "//vendor/golang.org/x/sys/unix:go_default_library",
+        ],
+        "//conditions:default": [],
+    }),
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

vendor/github.com/d2g/dhcp4client/README.md

+dhcp4client [![GoDoc](https://godoc.org/github.com/d2g/dhcp4client?status.svg)](http://godoc.org/github.com/d2g/dhcp4client) [![Coverage Status](https://coveralls.io/repos/d2g/dhcp4client/badge.svg?branch=HEAD)](https://coveralls.io/r/d2g/dhcp4client?branch=HEAD) [![Codeship Status for d2g/dhcp4client](https://codeship.com/projects/d75d9860-b364-0132-bc79-7e1d8cf367b9/status?branch=master)](https://codeship.com/projects/70187)
+===========
+
+DHCP Client
+
+
+###### Thanks to:
+@eyakubovich For AF_PACKET support.

vendor/github.com/d2g/dhcp4client/client.go

+package dhcp4client
+
+import (
+	"bytes"
+	"net"
+	"time"
+
+	"github.com/d2g/dhcp4"
+)
+
+const (
+	MaxDHCPLen = 576
+)
+
+type Client struct {
+	hardwareAddr  net.HardwareAddr //The HardwareAddr to send in the request.
+	ignoreServers []net.IP         //List of Servers to Ignore requests from.
+	timeout       time.Duration    //Time before we timeout.
+	broadcast     bool             //Set the Bcast flag in BOOTP Flags
+	connection    connection       //The Connection Method to use
+	generateXID   func([]byte)     //Function Used to Generate a XID
+}
+
+//Abstracts the type of underlying socket used
+type connection interface {
+	Close() error
+	Write(packet []byte) error
+	ReadFrom() ([]byte, net.IP, error)
+	SetReadTimeout(t time.Duration) error
+}
+
+func New(options ...func(*Client) error) (*Client, error) {
+	c := Client{
+		timeout:     time.Second * 10,
+		broadcast:   true,
+		generateXID: CryptoGenerateXID,
+	}
+
+	err := c.SetOption(options...)
+	if err != nil {
+		return nil, err
+	}
+
+	//if connection hasn't been set as an option create the default.
+	if c.connection == nil {
+		conn, err := NewInetSock()
+		if err != nil {
+			return nil, err
+		}
+		c.connection = conn
+	}
+
+	return &c, nil
+}
+
+func (c *Client) SetOption(options ...func(*Client) error) error {
+	for _, opt := range options {
+		if err := opt(c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func Timeout(t time.Duration) func(*Client) error {
+	return func(c *Client) error {
+		c.timeout = t
+		return nil
+	}
+}
+
+func IgnoreServers(s []net.IP) func(*Client) error {
+	return func(c *Client) error {
+		c.ignoreServers = s
+		return nil
+	}
+}
+
+func HardwareAddr(h net.HardwareAddr) func(*Client) error {
+	return func(c *Client) error {
+		c.hardwareAddr = h
+		return nil
+	}
+}
+
+func Broadcast(b bool) func(*Client) error {
+	return func(c *Client) error {
+		c.broadcast = b
+		return nil
+	}
+}
+
+func Connection(conn connection) func(*Client) error {
+	return func(c *Client) error {
+		c.connection = conn
+		return nil
+	}
+}
+
+func GenerateXID(g func([]byte)) func(*Client) error {
+	return func(c *Client) error {
+		c.generateXID = g
+		return nil
+	}
+}
+
+//Close Connections
+func (c *Client) Close() error {
+	if c.connection != nil {
+		return c.connection.Close()
+	}
+	return nil
+}
+
+//Send the Discovery Packet to the Broadcast Channel
+func (c *Client) SendDiscoverPacket() (dhcp4.Packet, error) {
+	discoveryPacket := c.DiscoverPacket()
+	discoveryPacket.PadToMinSize()
+
+	return discoveryPacket, c.SendPacket(discoveryPacket)
+}
+
+//Retreive Offer...
+//Wait for the offer for a specific Discovery Packet.
+func (c *Client) GetOffer(discoverPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	for {
+		c.connection.SetReadTimeout(c.timeout)
+		readBuffer, source, err := c.connection.ReadFrom()
+		if err != nil {
+			return dhcp4.Packet{}, err
+		}
+
+		offerPacket := dhcp4.Packet(readBuffer)
+		offerPacketOptions := offerPacket.ParseOptions()
+
+		// Ignore Servers in my Ignore list
+		for _, ignoreServer := range c.ignoreServers {
+			if source.Equal(ignoreServer) {
+				continue
+			}
+
+			if offerPacket.SIAddr().Equal(ignoreServer) {
+				continue
+			}
+		}
+
+		if len(offerPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || dhcp4.MessageType(offerPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.Offer || !bytes.Equal(discoverPacket.XId(), offerPacket.XId()) {
+			continue
+		}
+
+		return offerPacket, nil
+	}
+
+}
+
+//Send Request Based On the offer Received.
+func (c *Client) SendRequest(offerPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	requestPacket := c.RequestPacket(offerPacket)
+	requestPacket.PadToMinSize()
+
+	return requestPacket, c.SendPacket(requestPacket)
+}
+
+//Retreive Acknowledgement
+//Wait for the offer for a specific Request Packet.
+func (c *Client) GetAcknowledgement(requestPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	for {
+		c.connection.SetReadTimeout(c.timeout)
+		readBuffer, source, err := c.connection.ReadFrom()
+		if err != nil {
+			return dhcp4.Packet{}, err
+		}
+
+		acknowledgementPacket := dhcp4.Packet(readBuffer)
+		acknowledgementPacketOptions := acknowledgementPacket.ParseOptions()
+
+		// Ignore Servers in my Ignore list
+		for _, ignoreServer := range c.ignoreServers {
+			if source.Equal(ignoreServer) {
+				continue
+			}
+
+			if acknowledgementPacket.SIAddr().Equal(ignoreServer) {
+				continue
+			}
+		}
+
+		if !bytes.Equal(requestPacket.XId(), acknowledgementPacket.XId()) || len(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || (dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK && dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.NAK) {
+			continue
+		}
+
+		return acknowledgementPacket, nil
+	}
+}
+
+//Send Decline to the received acknowledgement.
+func (c *Client) SendDecline(acknowledgementPacket *dhcp4.Packet) (dhcp4.Packet, error) {
+	declinePacket := c.DeclinePacket(acknowledgementPacket)
+	declinePacket.PadToMinSize()
+
+	return declinePacket, c.SendPacket(declinePacket)
+}
+
+//Send a DHCP Packet.
+func (c *Client) SendPacket(packet dhcp4.Packet) error {
+	return c.connection.Write(packet)
+}
+
+//Create Discover Packet
+func (c *Client) DiscoverPacket() dhcp4.Packet {
+	messageid := make([]byte, 4)
+	c.generateXID(messageid)
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(c.hardwareAddr)
+	packet.SetXId(messageid)
+	packet.SetBroadcast(c.broadcast)
+
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Discover)})
+	//packet.PadToMinSize()
+	return packet
+}
+
+//Create Request Packet
+func (c *Client) RequestPacket(offerPacket *dhcp4.Packet) dhcp4.Packet {
+	offerOptions := offerPacket.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(c.hardwareAddr)
+
+	packet.SetXId(offerPacket.XId())
+	packet.SetCIAddr(offerPacket.CIAddr())
+	packet.SetSIAddr(offerPacket.SIAddr())
+
+	packet.SetBroadcast(c.broadcast)
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Request)})
+	packet.AddOption(dhcp4.OptionRequestedIPAddress, (offerPacket.YIAddr()).To4())
+	packet.AddOption(dhcp4.OptionServerIdentifier, offerOptions[dhcp4.OptionServerIdentifier])
+
+	return packet
+}
+
+//Create Request Packet For a Renew
+func (c *Client) RenewalRequestPacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
+	messageid := make([]byte, 4)
+	c.generateXID(messageid)
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(acknowledgement.CHAddr())
+
+	packet.SetXId(messageid)
+	packet.SetCIAddr(acknowledgement.YIAddr())
+	packet.SetSIAddr(acknowledgement.SIAddr())
+
+	packet.SetBroadcast(c.broadcast)
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Request)})
+	packet.AddOption(dhcp4.OptionRequestedIPAddress, (acknowledgement.YIAddr()).To4())
+	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])
+
+	return packet
+}
+
+//Create Release Packet For a Release
+func (c *Client) ReleasePacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
+	messageid := make([]byte, 4)
+	c.generateXID(messageid)
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(acknowledgement.CHAddr())
+
+	packet.SetXId(messageid)
+	packet.SetCIAddr(acknowledgement.YIAddr())
+
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Release)})
+	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])
+
+	return packet
+}
+
+//Create Decline Packet
+func (c *Client) DeclinePacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
+	messageid := make([]byte, 4)
+	c.generateXID(messageid)
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+
+	packet := dhcp4.NewPacket(dhcp4.BootRequest)
+	packet.SetCHAddr(acknowledgement.CHAddr())
+	packet.SetXId(messageid)
+
+	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Decline)})
+	packet.AddOption(dhcp4.OptionRequestedIPAddress, (acknowledgement.YIAddr()).To4())
+	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])
+
+	return packet
+}
+
+
+//Lets do a Full DHCP Request.
+func (c *Client) Request() (bool, dhcp4.Packet, error) {
+	discoveryPacket, err := c.SendDiscoverPacket()
+	if err != nil {
+		return false, discoveryPacket, err
+	}
+
+	offerPacket, err := c.GetOffer(&discoveryPacket)
+	if err != nil {
+		return false, offerPacket, err
+	}
+
+	requestPacket, err := c.SendRequest(&offerPacket)
+	if err != nil {
+		return false, requestPacket, err
+	}
+
+	acknowledgement, err := c.GetAcknowledgement(&requestPacket)
+	if err != nil {
+		return false, acknowledgement, err
+	}
+
+	acknowledgementOptions := acknowledgement.ParseOptions()
+	if dhcp4.MessageType(acknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
+		return false, acknowledgement, nil
+	}
+
+	return true, acknowledgement, nil
+}
+
+//Renew a lease backed on the Acknowledgement Packet.
+//Returns Sucessfull, The AcknoledgementPacket, Any Errors
+func (c *Client) Renew(acknowledgement dhcp4.Packet) (bool, dhcp4.Packet, error) {
+	renewRequest := c.RenewalRequestPacket(&acknowledgement)
+	renewRequest.PadToMinSize()
+
+	err := c.SendPacket(renewRequest)
+	if err != nil {
+		return false, renewRequest, err
+	}
+
+	newAcknowledgement, err := c.GetAcknowledgement(&renewRequest)
+	if err != nil {
+		return false, newAcknowledgement, err
+	}
+
+	newAcknowledgementOptions := newAcknowledgement.ParseOptions()
+	if dhcp4.MessageType(newAcknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
+		return false, newAcknowledgement, nil
+	}
+
+	return true, newAcknowledgement, nil
+}
+
+//Release a lease backed on the Acknowledgement Packet.
+//Returns Any Errors
+func (c *Client) Release(acknowledgement dhcp4.Packet) error {
+	release := c.ReleasePacket(&acknowledgement)
+	release.PadToMinSize()
+
+	return c.SendPacket(release)
+}

vendor/github.com/d2g/dhcp4client/generatexid.go

+package dhcp4client
+
+import (
+	cryptorand "crypto/rand"
+	mathrand "math/rand"
+)
+
+func CryptoGenerateXID(b []byte) {
+	if _, err := cryptorand.Read(b); err != nil {
+		panic(err)
+	}
+}
+
+func MathGenerateXID(b []byte) {
+	if _, err := mathrand.Read(b); err != nil {
+		panic(err)
+	}
+}

vendor/github.com/d2g/dhcp4client/inetsock.go

+package dhcp4client
+
+import (
+	"net"
+	"time"
+)
+
+type inetSock struct {
+	*net.UDPConn
+
+	laddr net.UDPAddr
+	raddr net.UDPAddr
+}
+
+func NewInetSock(options ...func(*inetSock) error) (*inetSock, error) {
+	c := &inetSock{
+		laddr: net.UDPAddr{IP: net.IPv4(0, 0, 0, 0), Port: 68},
+		raddr: net.UDPAddr{IP: net.IPv4bcast, Port: 67},
+	}
+
+	err := c.setOption(options...)
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.ListenUDP("udp4", &c.laddr)
+	if err != nil {
+		return nil, err
+	}
+
+	c.UDPConn = conn
+	return c, err
+}
+
+func (c *inetSock) setOption(options ...func(*inetSock) error) error {
+	for _, opt := range options {
+		if err := opt(c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func SetLocalAddr(l net.UDPAddr) func(*inetSock) error {
+	return func(c *inetSock) error {
+		c.laddr = l
+		return nil
+	}
+}
+
+func SetRemoteAddr(r net.UDPAddr) func(*inetSock) error {
+	return func(c *inetSock) error {
+		c.raddr = r
+		return nil
+	}
+}
+
+func (c *inetSock) Write(packet []byte) error {
+	_, err := c.WriteToUDP(packet, &c.raddr)
+	return err
+}
+
+func (c *inetSock) ReadFrom() ([]byte, net.IP, error) {
+	readBuffer := make([]byte, MaxDHCPLen)
+	n, source, err := c.ReadFromUDP(readBuffer)
+	if source != nil {
+		return readBuffer[:n], source.IP, err
+	} else {
+		return readBuffer[:n], net.IP{}, err
+	}
+}
+
+func (c *inetSock) SetReadTimeout(t time.Duration) error {
+	return c.SetReadDeadline(time.Now().Add(t))
+}

vendor/github.com/d2g/dhcp4client/pktsock_linux.go

+package dhcp4client
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"net"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	minIPHdrLen = 20
+	maxIPHdrLen = 60
+	udpHdrLen   = 8
+	ip4Ver      = 0x40
+	ttl         = 16
+	srcPort     = 68
+	dstPort     = 67
+)
+
+var (
+	bcastMAC = []byte{255, 255, 255, 255, 255, 255}
+)
+
+// abstracts AF_PACKET
+type packetSock struct {
+	fd      int
+	ifindex int
+}
+
+func NewPacketSock(ifindex int) (*packetSock, error) {
+	fd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_DGRAM, int(swap16(unix.ETH_P_IP)))
+	if err != nil {
+		return nil, err
+	}
+
+	addr := unix.SockaddrLinklayer{
+		Ifindex:  ifindex,
+		Protocol: swap16(unix.ETH_P_IP),
+	}
+
+	if err = unix.Bind(fd, &addr); err != nil {
+		return nil, err
+	}
+
+	return &packetSock{
+		fd:      fd,
+		ifindex: ifindex,
+	}, nil
+}
+
+func (pc *packetSock) Close() error {
+	return unix.Close(pc.fd)
+}
+
+func (pc *packetSock) Write(packet []byte) error {
+	lladdr := unix.SockaddrLinklayer{
+		Ifindex:  pc.ifindex,
+		Protocol: swap16(unix.ETH_P_IP),
+		Halen:    uint8(len(bcastMAC)),
+	}
+	copy(lladdr.Addr[:], bcastMAC)
+
+	pkt := make([]byte, minIPHdrLen+udpHdrLen+len(packet))
+
+	fillIPHdr(pkt[0:minIPHdrLen], udpHdrLen+uint16(len(packet)))
+	fillUDPHdr(pkt[minIPHdrLen:minIPHdrLen+udpHdrLen], uint16(len(packet)))
+
+	// payload
+	copy(pkt[minIPHdrLen+udpHdrLen:len(pkt)], packet)
+
+	return unix.Sendto(pc.fd, pkt, 0, &lladdr)
+}
+
+func (pc *packetSock) ReadFrom() ([]byte, net.IP, error) {
+	pkt := make([]byte, maxIPHdrLen+udpHdrLen+MaxDHCPLen)
+	n, _, err := unix.Recvfrom(pc.fd, pkt, 0)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// IP hdr len
+	ihl := int(pkt[0]&0x0F) * 4
+	// Source IP address
+	src := net.IP(pkt[12:16])
+
+	return pkt[ihl+udpHdrLen : n], src, nil
+}
+
+func (pc *packetSock) SetReadTimeout(t time.Duration) error {
+
+	tv := unix.NsecToTimeval(t.Nanoseconds())
+	return unix.SetsockoptTimeval(pc.fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &tv)
+}
+
+// compute's 1's complement checksum
+func chksum(p []byte, csum []byte) {
+	cklen := len(p)
+	s := uint32(0)
+	for i := 0; i < (cklen - 1); i += 2 {
+		s += uint32(p[i+1])<<8 | uint32(p[i])
+	}
+	if cklen&1 == 1 {
+		s += uint32(p[cklen-1])
+	}
+	s = (s >> 16) + (s & 0xffff)
+	s = s + (s >> 16)
+	s = ^s
+
+	csum[0] = uint8(s & 0xff)
+	csum[1] = uint8(s >> 8)
+}
+
+func fillIPHdr(hdr []byte, payloadLen uint16) {
+	// version + IHL
+	hdr[0] = ip4Ver | (minIPHdrLen / 4)
+	// total length
+	binary.BigEndian.PutUint16(hdr[2:4], uint16(len(hdr))+payloadLen)
+	// identification
+	if _, err := rand.Read(hdr[4:5]); err != nil {
+		panic(err)
+	}
+	// TTL
+	hdr[8] = 16
+	// Protocol
+	hdr[9] = unix.IPPROTO_UDP
+	// dst IP
+	copy(hdr[16:20], net.IPv4bcast.To4())
+	// compute IP hdr checksum
+	chksum(hdr[0:len(hdr)], hdr[10:12])
+}
+
+func fillUDPHdr(hdr []byte, payloadLen uint16) {
+	// src port
+	binary.BigEndian.PutUint16(hdr[0:2], srcPort)
+	// dest port
+	binary.BigEndian.PutUint16(hdr[2:4], dstPort)
+	// length
+	binary.BigEndian.PutUint16(hdr[4:6], udpHdrLen+payloadLen)
+}
+
+func swap16(x uint16) uint16 {
+	var b [2]byte
+	binary.BigEndian.PutUint16(b[:], x)
+	return binary.LittleEndian.Uint16(b[:])
+}