podman: add support for specifying MAC

I basically copied and adapted the statements for setting IP.

Closes #1136

Signed-off-by: Jakub Filak <jakub.filak@sap.com>

5 files changed, 107 insertions, 16 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 8e24391b9..4f7fc067e 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -138,6 +138,10 @@ type Container struct {
 	// being checkpointed. If requestedIP is set it will be used instead
 	// of config.StaticIP.
 	requestedIP net.IP
+	// A restored container should have the same MAC address as before
+	// being checkpointed. If requestedMAC is set it will be used instead
+	// of config.StaticMAC.
+	requestedMAC net.HardwareAddr
 
 	// This is true if a container is restored from a checkpoint.
 	restoreFromCheckpoint bool
@@ -296,6 +300,10 @@ type ContainerConfig struct {
 	// This cannot be set unless CreateNetNS is set.
 	// If not set, the container will be dynamically assigned an IP by CNI.
 	StaticIP net.IP `json:"staticIP"`
+	// StaticMAC is a static MAC to request for the container.
+	// This cannot be set unless CreateNetNS is set.
+	// If not set, the container will be dynamically assigned a MAC by CNI.
+	StaticMAC net.HardwareAddr `json:"staticMAC"`
 	// PortMappings are the ports forwarded to the container's network
 	// namespace
 	// These are not used unless CreateNetNS is true
diff --git a/libpod/container_api.go b/libpod/container_api.go
index a6f5b54d5..b8cfe02f6 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -794,6 +794,11 @@ type ContainerCheckpointOptions struct {
 	// important to be able to restore a container multiple
 	// times with '--import --name'.
 	IgnoreStaticIP bool
+	// IgnoreStaticMAC tells the API to ignore the MAC set
+	// during 'podman run' with '--mac-address'. This is especially
+	// important to be able to restore a container multiple
+	// times with '--import --name'.
+	IgnoreStaticMAC bool
 }
 
 // Checkpoint checkpoints a container
diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 471648bc8..26d6771b0 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -794,6 +794,15 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 		c.config.StaticIP = nil
 	}
 
+	// If a container is restored multiple times from an exported checkpoint with
+	// the help of '--import --name', the restore will fail if during 'podman run'
+	// a static container MAC address was set with '--mac-address'. The user
+	// can tell the restore process to ignore the static MAC with
+	// '--ignore-static-mac'
+	if options.IgnoreStaticMAC {
+		c.config.StaticMAC = nil
+	}
+
 	// Read network configuration from checkpoint
 	// Currently only one interface with one IP is supported.
 	networkStatusFile, err := os.Open(filepath.Join(c.bundlePath(), "network.status"))
@@ -803,9 +812,9 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 	// TODO: This implicit restoring with or without IP depending on an
 	//       unrelated restore parameter (--name) does not seem like the
 	//       best solution.
-	if err == nil && options.Name == "" && !options.IgnoreStaticIP {
+	if err == nil && options.Name == "" && (!options.IgnoreStaticIP || !options.IgnoreStaticMAC) {
 		// The file with the network.status does exist. Let's restore the
-		// container with the same IP address as during checkpointing.
+		// container with the same IP address / MAC address as during checkpointing.
 		defer networkStatusFile.Close()
 		var networkStatus []*cnitypes.Result
 		networkJSON, err := ioutil.ReadAll(networkStatusFile)
@@ -815,16 +824,35 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 		if err := json.Unmarshal(networkJSON, &networkStatus); err != nil {
 			return err
 		}
-		// Take the first IP address
-		var IP net.IP
-		if len(networkStatus) > 0 {
-			if len(networkStatus[0].IPs) > 0 {
-				IP = networkStatus[0].IPs[0].Address.IP
+		if !options.IgnoreStaticIP {
+			// Take the first IP address
+			var IP net.IP
+			if len(networkStatus) > 0 {
+				if len(networkStatus[0].IPs) > 0 {
+					IP = networkStatus[0].IPs[0].Address.IP
+				}
+			}
+			if IP != nil {
+				// Tell CNI which IP address we want.
+				c.requestedIP = IP
 			}
 		}
-		if IP != nil {
-			// Tell CNI which IP address we want.
-			c.requestedIP = IP
+		if !options.IgnoreStaticMAC {
+			// Take the first device with a defined sandbox.
+			var MAC net.HardwareAddr
+			for _, n := range networkStatus[0].Interfaces {
+				if n.Sandbox != "" {
+					MAC, err = net.ParseMAC(n.Mac)
+					if err != nil {
+						return errors.Wrapf(err, "failed to parse MAC %v", n.Mac)
+					}
+					break
+				}
+			}
+			if MAC != nil {
+				// Tell CNI which MAC address we want.
+				c.requestedMAC = MAC
+			}
 		}
 	}
 
@@ -1314,7 +1342,7 @@ func (c *Container) copyOwnerAndPerms(source, dest string) error {
 // Teardown CNI config on refresh
 func (c *Container) refreshCNI() error {
 	// Let's try and delete any lingering network config...
-	podNetwork := c.runtime.getPodNetwork(c.ID(), c.config.Name, "", c.config.Networks, c.config.PortMappings, c.config.StaticIP)
+	podNetwork := c.runtime.getPodNetwork(c.ID(), c.config.Name, "", c.config.Networks, c.config.PortMappings, c.config.StaticIP, c.config.StaticMAC)
 	return c.runtime.netPlugin.TearDownPod(podNetwork)
 }
 
diff --git a/libpod/networking_linux.go b/libpod/networking_linux.go
index 8172e3fb2..cba7b636a 100644
--- a/libpod/networking_linux.go
+++ b/libpod/networking_linux.go
@@ -28,7 +28,7 @@ import (
 )
 
 // Get an OCICNI network config
-func (r *Runtime) getPodNetwork(id, name, nsPath string, networks []string, ports []ocicni.PortMapping, staticIP net.IP) ocicni.PodNetwork {
+func (r *Runtime) getPodNetwork(id, name, nsPath string, networks []string, ports []ocicni.PortMapping, staticIP net.IP, staticMAC net.HardwareAddr) ocicni.PodNetwork {
 	defaultNetwork := r.netPlugin.GetDefaultNetworkName()
 	network := ocicni.PodNetwork{
 		Name:      name,
@@ -40,10 +40,17 @@ func (r *Runtime) getPodNetwork(id, name, nsPath string, networks []string, port
 		},
 	}
 
-	if staticIP != nil {
+	if staticIP != nil || staticMAC != nil {
 		network.Networks = []ocicni.NetAttachment{{Name: defaultNetwork}}
+		var rt ocicni.RuntimeConfig = ocicni.RuntimeConfig{PortMappings: ports}
+		if staticIP != nil {
+			rt.IP = staticIP.String()
+		}
+		if staticMAC != nil {
+			rt.MAC = staticMAC.String()
+		}
 		network.RuntimeConfig = map[string]ocicni.RuntimeConfig{
-			defaultNetwork: {IP: staticIP.String(), PortMappings: ports},
+			defaultNetwork: rt,
 		}
 	} else {
 		network.Networks = make([]ocicni.NetAttachment, len(networks))
@@ -66,7 +73,16 @@ func (r *Runtime) configureNetNS(ctr *Container, ctrNS ns.NetNS) ([]*cnitypes.Re
 		requestedIP = ctr.config.StaticIP
 	}
 
-	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP)
+	var requestedMAC net.HardwareAddr
+	if ctr.requestedMAC != nil {
+		requestedMAC = ctr.requestedMAC
+		// cancel request for a specific MAC in case the container is reused later
+		ctr.requestedMAC = nil
+	} else {
+		requestedMAC = ctr.config.StaticMAC
+	}
+
+	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP, requestedMAC)
 
 	results, err := r.netPlugin.SetUpPod(podNetwork)
 	if err != nil {
@@ -447,7 +463,16 @@ func (r *Runtime) teardownNetNS(ctr *Container) error {
 			requestedIP = ctr.config.StaticIP
 		}
 
-		podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP)
+		var requestedMAC net.HardwareAddr
+		if ctr.requestedMAC != nil {
+			requestedMAC = ctr.requestedMAC
+			// cancel request for a specific MAC in case the container is reused later
+			ctr.requestedMAC = nil
+		} else {
+			requestedMAC = ctr.config.StaticMAC
+		}
+
+		podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP, requestedMAC)
 
 		if err := r.netPlugin.TearDownPod(podNetwork); err != nil {
 			return errors.Wrapf(err, "error tearing down CNI namespace configuration for container %s", ctr.ID())
diff --git a/libpod/options.go b/libpod/options.go
index 66e8ef93c..00b5626b4 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -1052,6 +1052,31 @@ func WithStaticIP(ip net.IP) CtrCreateOption {
 	}
 }
 
+// WithStaticMAC indicates that the container should request a static MAC from
+// the CNI plugins.
+// It cannot be set unless WithNetNS has already been passed.
+// Further, it cannot be set if additional CNI networks to join have been
+// specified.
+func WithStaticMAC(mac net.HardwareAddr) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return define.ErrCtrFinalized
+		}
+
+		if !ctr.config.CreateNetNS {
+			return errors.Wrapf(define.ErrInvalidArg, "cannot set a static MAC if the container is not creating a network namespace")
+		}
+
+		if len(ctr.config.Networks) != 0 {
+			return errors.Wrapf(define.ErrInvalidArg, "cannot set a static MAC if joining additional CNI networks")
+		}
+
+		ctr.config.StaticMAC = mac
+
+		return nil
+	}
+}
+
 // WithLogDriver sets the log driver for the container
 func WithLogDriver(driver string) CtrCreateOption {
 	return func(ctr *Container) error {