network: allow slirp4netns mode also for root containers

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

docs/podman-create.1.md

@@ -426,7 +426,8 @@ Set the Network mode for the container
                 'container:<name|id>': reuse another container's network stack
                 'host': use the podman host network stack.  Note: the host mode gives the container full access to local system services such as D-bus and is therefore considered insecure.
                 '<network-name>|<network-id>': connect to a user-defined network
-                'ns:<path>' path to a network namespace to join
+                'ns:<path>': path to a network namespace to join
+                'slirp4netns': use slirp4netns to create a user network stack.  This is the default for rootless containers
 
 **--network-alias**=[]
 

docs/podman-run.1.md

@@ -408,7 +408,8 @@ Set the Network mode for the container:
 - `container:<name|id>`: reuse another container's network stack
 - `host`: use the podman host network stack. Note: the host mode gives the container full access to local system services such as D-bus and is therefore considered insecure.
 - `<network-name>|<network-id>`: connect to a user-defined network
-- `ns:<path>` path to a network namespace to join
+- `ns:<path>`: path to a network namespace to join
+- `slirp4netns`: use slirp4netns to create a user network stack.  This is the default for rootless containers
 
 **--network-alias**=[]
 

libpod/container.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/containernetworking/cni/pkg/types"
 	cnitypes "github.com/containernetworking/cni/pkg/types/current"
+	"github.com/containers/libpod/pkg/namespaces"
 	"github.com/containers/storage"
 	"github.com/cri-o/ocicni/pkg/ocicni"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
@@ -296,6 +297,8 @@ type ContainerConfig struct {
 	HostAdd []string `json:"hostsAdd,omitempty"`
 	// Network names (CNI) to add container to. Empty to use default network.
 	Networks []string `json:"networks,omitempty"`
+	// Network mode specified for the default network.
+	NetMode namespaces.NetworkMode `json:"networkMode,omitempty"`
 
 	// Image Config
 

libpod/container_easyjson.go

@@ -8,6 +8,7 @@ import (
 	json "encoding/json"
 	types "github.com/containernetworking/cni/pkg/types"
 	current "github.com/containernetworking/cni/pkg/types/current"
+	namespaces "github.com/containers/libpod/pkg/namespaces"
 	storage "github.com/containers/storage"
 	idtools "github.com/containers/storage/pkg/idtools"
 	ocicni "github.com/cri-o/ocicni/pkg/ocicni"
@@ -1550,6 +1551,8 @@ func easyjson1dbef17bDecodeGithubComContainersLibpodLibpod2(in *jlexer.Lexer, ou
 				}
 				in.Delim(']')
 			}
+		case "networkMode":
+			out.NetMode = namespaces.NetworkMode(in.String())
 		case "userVolumes":
 			if in.IsNull() {
 				in.Skip()
@@ -2177,6 +2180,16 @@ func easyjson1dbef17bEncodeGithubComContainersLibpodLibpod2(out *jwriter.Writer,
 			out.RawByte(']')
 		}
 	}
+	if in.NetMode != "" {
+		const prefix string = ",\"networkMode\":"
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
+		out.String(string(in.NetMode))
+	}
 	if len(in.UserVolumes) != 0 {
 		const prefix string = ",\"userVolumes\":"
 		if first {

libpod/container_internal.go

@@ -586,7 +586,7 @@ func (c *Container) completeNetworkSetup() error {
 	if err := c.syncContainer(); err != nil {
 		return err
 	}
-	if rootless.IsRootless() {
+	if c.config.NetMode == "slirp4netns" {
 		return c.runtime.setupRootlessNetNS(c)
 	}
 	return c.runtime.setupNetNS(c)

libpod/oci.go

@@ -329,7 +329,7 @@ func (r *OCIRuntime) createOCIContainer(ctr *Container, cgroupParent string, res
 		cmd.ExtraFiles = append(cmd.ExtraFiles, ports...)
 	}
 
-	if rootless.IsRootless() {
+	if ctr.config.NetMode.IsSlirp4netns() {
 		ctr.rootlessSlirpSyncR, ctr.rootlessSlirpSyncW, err = os.Pipe()
 		if err != nil {
 			return errors.Wrapf(err, "failed to create rootless network sync pipe")

libpod/options.go

@@ -7,6 +7,7 @@ import (
 	"regexp"
 	"syscall"
 
+	"github.com/containers/libpod/pkg/namespaces"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/idtools"
 	"github.com/cri-o/ocicni/pkg/ocicni"
@@ -817,7 +818,7 @@ func WithDependencyCtrs(ctrs []*Container) CtrCreateOption {
 // namespace with a minimal configuration.
 // An optional array of port mappings can be provided.
 // Conflicts with WithNetNSFrom().
-func WithNetNS(portMappings []ocicni.PortMapping, postConfigureNetNS bool, networks []string) CtrCreateOption {
+func WithNetNS(portMappings []ocicni.PortMapping, postConfigureNetNS bool, netmode string, networks []string) CtrCreateOption {
 	return func(ctr *Container) error {
 		if ctr.valid {
 			return ErrCtrFinalized
@@ -831,6 +832,7 @@ func WithNetNS(portMappings []ocicni.PortMapping, postConfigureNetNS bool, netwo
 		ctr.config.CreateNetNS = true
 		ctr.config.PortMappings = portMappings
 		ctr.config.Networks = networks
+		ctr.config.NetMode = namespaces.NetworkMode(netmode)
 
 		return nil
 	}

libpod/runtime_pod_infra_linux.go

@@ -50,7 +50,11 @@ func (r *Runtime) makeInfraContainer(ctx context.Context, p *Pod, imgName, imgID
 
 	// Since user namespace sharing is not implemented, we only need to check if it's rootless
 	networks := make([]string, 0)
-	options = append(options, WithNetNS(p.config.InfraContainer.PortBindings, isRootless, networks))
+	netmode := "bridge"
+	if isRootless {
+		netmode = "slirp4netns"
+	}
+	options = append(options, WithNetNS(p.config.InfraContainer.PortBindings, isRootless, netmode, networks))
 
 	return r.newContainer(ctx, g.Config, options...)
 }

pkg/spec/createconfig.go

@@ -391,11 +391,11 @@ func (c *CreateConfig) GetContainerCreateOptions(runtime *libpod.Runtime) ([]lib
 		options = append(options, libpod.WithNetNSFrom(connectedCtr))
 	} else if !c.NetMode.IsHost() && !c.NetMode.IsNone() {
 		isRootless := rootless.IsRootless()
-		postConfigureNetNS := isRootless || (len(c.IDMappings.UIDMap) > 0 || len(c.IDMappings.GIDMap) > 0) && !c.UsernsMode.IsHost()
+		postConfigureNetNS := c.NetMode.IsSlirp4netns() || (len(c.IDMappings.UIDMap) > 0 || len(c.IDMappings.GIDMap) > 0) && !c.UsernsMode.IsHost()
 		if isRootless && len(portBindings) > 0 {
 			return nil, errors.New("port bindings are not yet supported by rootless containers")
 		}
-		options = append(options, libpod.WithNetNS(portBindings, postConfigureNetNS, networks))
+		options = append(options, libpod.WithNetNS(portBindings, postConfigureNetNS, string(c.NetMode), networks))
 	}
 
 	if c.PidMode.IsContainer() {