Merge pull request #2931 from TomSweeneyRedHat/dev/tsweeney/venbuildah

Vendor in latest Buildah

27 files changed, 2801 insertions, 335 deletions

diff --git a/vendor/github.com/containers/buildah/add.go b/vendor/github.com/containers/buildah/add.go
index 250d75b24..d42246d53 100644
--- a/vendor/github.com/containers/buildah/add.go
+++ b/vendor/github.com/containers/buildah/add.go
@@ -209,6 +209,10 @@ func DockerIgnoreHelper(lines []string, contextDir string) []DockerIgnore {
 }
 
 func addHelper(excludes []DockerIgnore, extract bool, dest string, destfi os.FileInfo, hostOwner idtools.IDPair, options AddAndCopyOptions, copyFileWithTar, copyWithTar, untarPath func(src, dest string) error, source ...string) error {
+	dirsInDockerignore, err := getDirsInDockerignore(options.ContextDir, excludes)
+	if err != nil {
+		return errors.Wrapf(err, "error checking directories in .dockerignore")
+	}
 	for _, src := range source {
 		if strings.HasPrefix(src, "http://") || strings.HasPrefix(src, "https://") {
 			// We assume that source is a file, and we're copying
@@ -274,10 +278,15 @@ func addHelper(excludes []DockerIgnore, extract bool, dest string, destfi os.Fil
 						if err != nil {
 							return err
 						}
-						if !match {
+						prefix, exist := dirsInDockerignore[exclude.ExcludePath]
+						hasPrefix := false
+						if exist {
+							hasPrefix = filepath.HasPrefix(path, prefix)
+						}
+						if !(match || hasPrefix) {
 							continue
 						}
-						if exclude.IsExcluded {
+						if (hasPrefix && exclude.IsExcluded) || (match && exclude.IsExcluded) {
 							return nil
 						}
 						break
@@ -333,3 +342,35 @@ func addHelper(excludes []DockerIgnore, extract bool, dest string, destfi os.Fil
 	}
 	return nil
 }
+
+func getDirsInDockerignore(srcAbsPath string, excludes []DockerIgnore) (map[string]string, error) {
+	visitedDir := make(map[string]string)
+	if len(excludes) == 0 {
+		return visitedDir, nil
+	}
+	err := filepath.Walk(srcAbsPath, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			for _, exclude := range excludes {
+				match, err := filepath.Match(filepath.Clean(exclude.ExcludePath), filepath.Clean(path))
+				if err != nil {
+					return err
+				}
+				if !match {
+					continue
+				}
+				if _, exist := visitedDir[exclude.ExcludePath]; exist {
+					continue
+				}
+				visitedDir[exclude.ExcludePath] = path
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return visitedDir, err
+	}
+	return visitedDir, nil
+}
diff --git a/vendor/github.com/containers/buildah/buildah.go b/vendor/github.com/containers/buildah/buildah.go
index 9625fff96..8b076630f 100644
--- a/vendor/github.com/containers/buildah/buildah.go
+++ b/vendor/github.com/containers/buildah/buildah.go
@@ -26,7 +26,7 @@ const (
 	Package = "buildah"
 	// Version for the Package.  Bump version in contrib/rpm/buildah.spec
 	// too.
-	Version = "1.7.2"
+	Version = "1.8-dev"
 	// The value we use to identify what type of information, currently a
 	// serialized Builder structure, we are using as per-container state.
 	// This should only be changed when we make incompatible changes to
@@ -284,6 +284,12 @@ type CommonBuildOptions struct {
 	CPUSetMems string
 	// Memory is the upper limit (in bytes) on how much memory running containers can use.
 	Memory int64
+	// DNSSearch is the list of DNS search domains to add to the build container's /etc/resolv.conf
+	DNSSearch []string
+	// DNSServers is the list of DNS servers to add to the build container's /etc/resolv.conf
+	DNSServers []string
+	// DNSOptions is the list of DNS
+	DNSOptions []string
 	// MemorySwap limits the amount of memory and swap together.
 	MemorySwap int64
 	// LabelOpts is the a slice of fields of an SELinux context, given in "field:pair" format, or "disable".
diff --git a/vendor/github.com/containers/buildah/chroot/run.go b/vendor/github.com/containers/buildah/chroot/run.go
index 9bcac1683..ff39c2f24 100644
--- a/vendor/github.com/containers/buildah/chroot/run.go
+++ b/vendor/github.com/containers/buildah/chroot/run.go
@@ -18,7 +18,7 @@ import (
 	"unsafe"
 
 	"github.com/containers/buildah/bind"
-	"github.com/containers/buildah/unshare"
+	"github.com/containers/buildah/pkg/unshare"
 	"github.com/containers/buildah/util"
 	"github.com/containers/storage/pkg/ioutils"
 	"github.com/containers/storage/pkg/mount"
diff --git a/vendor/github.com/containers/buildah/commit.go b/vendor/github.com/containers/buildah/commit.go
index 9ab90196c..5e73be881 100644
--- a/vendor/github.com/containers/buildah/commit.go
+++ b/vendor/github.com/containers/buildah/commit.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"strings"
 	"time"
 
 	"github.com/containers/buildah/pkg/blobcache"
@@ -18,6 +19,7 @@ import (
 	"github.com/containers/image/types"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/stringid"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -110,10 +112,28 @@ type PushOptions struct {
 // Commit writes the contents of the container, along with its updated
 // configuration, to a new image in the specified location, and if we know how,
 // add any additional tags that were specified. Returns the ID of the new image
-// if commit was successful and the image destination was local
+// if commit was successful and the image destination was local.
 func (b *Builder) Commit(ctx context.Context, dest types.ImageReference, options CommitOptions) (string, reference.Canonical, digest.Digest, error) {
 	var imgID string
 
+	// If we weren't given a name, build a destination reference using a
+	// temporary name that we'll remove later.  The correct thing to do
+	// would be to read the manifest and configuration blob, and ask the
+	// manifest for the ID that we'd give the image, but that computation
+	// requires that we know the digests of the layer blobs, which we don't
+	// want to compute here because we'll have to do it again when
+	// cp.Image() instantiates a source image, and we don't want to do the
+	// work twice.
+	nameToRemove := ""
+	if dest == nil {
+		nameToRemove = stringid.GenerateRandomID() + "-tmp"
+		dest2, err := is.Transport.ParseStoreReference(b.store, nameToRemove)
+		if err != nil {
+			return imgID, nil, "", errors.Wrapf(err, "error creating temporary destination reference for image")
+		}
+		dest = dest2
+	}
+
 	systemContext := getSystemContext(b.store, options.SystemContext, options.SignaturePolicyPath)
 
 	blocked, err := isReferenceBlocked(dest, systemContext)
@@ -148,10 +168,13 @@ func (b *Builder) Commit(ctx context.Context, dest types.ImageReference, options
 			}
 		}
 	}
+	// Build an image reference from which we can copy the finished image.
 	src, err := b.makeImageRef(options.PreferredManifestType, options.Parent, exportBaseLayers, options.Squash, options.BlobDirectory, options.Compression, options.HistoryTimestamp, options.OmitTimestamp)
 	if err != nil {
 		return imgID, nil, "", errors.Wrapf(err, "error computing layer digests and building metadata for container %q", b.ContainerID)
 	}
+	// In case we're using caching, decide how to handle compression for a cache.
+	// If we're using blob caching, set it up for the source.
 	var maybeCachedSrc = types.ImageReference(src)
 	var maybeCachedDest = types.ImageReference(dest)
 	if options.BlobDirectory != "" {
@@ -181,6 +204,8 @@ func (b *Builder) Commit(ctx context.Context, dest types.ImageReference, options
 	if manifestBytes, err = cp.Image(ctx, policyContext, maybeCachedDest, maybeCachedSrc, getCopyOptions(b.store, options.ReportWriter, maybeCachedSrc, nil, maybeCachedDest, systemContext, "")); err != nil {
 		return imgID, nil, "", errors.Wrapf(err, "error copying layers and metadata for container %q", b.ContainerID)
 	}
+	// If we've got more names to attach, and we know how to do that for
+	// the transport that we're writing the new image to, add them now.
 	if len(options.AdditionalTags) > 0 {
 		switch dest.Transport().Name() {
 		case is.Transport.Name():
@@ -201,10 +226,25 @@ func (b *Builder) Commit(ctx context.Context, dest types.ImageReference, options
 	if err != nil && err != storage.ErrImageUnknown {
 		return imgID, nil, "", errors.Wrapf(err, "error locating image %q in local storage", transports.ImageName(dest))
 	}
-
 	if err == nil {
 		imgID = img.ID
-
+		prunedNames := make([]string, 0, len(img.Names))
+		for _, name := range img.Names {
+			if !(nameToRemove != "" && strings.Contains(name, nameToRemove)) {
+				prunedNames = append(prunedNames, name)
+			}
+		}
+		if len(prunedNames) < len(img.Names) {
+			if err = b.store.SetNames(imgID, prunedNames); err != nil {
+				return imgID, nil, "", errors.Wrapf(err, "failed to prune temporary name from image %q", imgID)
+			}
+			logrus.Debugf("reassigned names %v to image %q", prunedNames, img.ID)
+			dest2, err := is.Transport.ParseStoreReference(b.store, "@"+imgID)
+			if err != nil {
+				return imgID, nil, "", errors.Wrapf(err, "error creating unnamed destination reference for image")
+			}
+			dest = dest2
+		}
 		if options.IIDFile != "" {
 			if err = ioutil.WriteFile(options.IIDFile, []byte(img.ID), 0644); err != nil {
 				return imgID, nil, "", errors.Wrapf(err, "failed to write image ID to file %q", options.IIDFile)
diff --git a/vendor/github.com/containers/buildah/common.go b/vendor/github.com/containers/buildah/common.go
index 667a1a484..6b4e2ee90 100644
--- a/vendor/github.com/containers/buildah/common.go
+++ b/vendor/github.com/containers/buildah/common.go
@@ -5,7 +5,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/containers/buildah/unshare"
+	"github.com/containers/buildah/pkg/unshare"
 	cp "github.com/containers/image/copy"
 	"github.com/containers/image/types"
 	"github.com/containers/storage"
diff --git a/vendor/github.com/containers/buildah/image.go b/vendor/github.com/containers/buildah/image.go
index b0876fb6d..1cd329c85 100644
--- a/vendor/github.com/containers/buildah/image.go
+++ b/vendor/github.com/containers/buildah/image.go
@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/containers/buildah/docker"
@@ -661,6 +662,13 @@ func (b *Builder) makeImageRef(manifestType, parent string, exporting bool, squa
 	if historyTimestamp != nil {
 		created = historyTimestamp.UTC()
 	}
+	createdBy := b.CreatedBy()
+	if createdBy == "" {
+		createdBy = strings.Join(b.Shell(), " ")
+		if createdBy == "" {
+			createdBy = "/bin/sh"
+		}
+	}
 
 	if omitTimestamp {
 		created = time.Unix(0, 0)
@@ -677,7 +685,7 @@ func (b *Builder) makeImageRef(manifestType, parent string, exporting bool, squa
 		oconfig:               oconfig,
 		dconfig:               dconfig,
 		created:               created,
-		createdBy:             b.CreatedBy(),
+		createdBy:             createdBy,
 		historyComment:        b.HistoryComment(),
 		annotations:           b.Annotations(),
 		preferredManifestType: manifestType,
diff --git a/vendor/github.com/containers/buildah/imagebuildah/build.go b/vendor/github.com/containers/buildah/imagebuildah/build.go
index b1e30ca6a..b692d3bcf 100644
--- a/vendor/github.com/containers/buildah/imagebuildah/build.go
+++ b/vendor/github.com/containers/buildah/imagebuildah/build.go
@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -28,7 +27,6 @@ import (
 	"github.com/containers/image/types"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/archive"
-	"github.com/containers/storage/pkg/stringid"
 	docker "github.com/fsouza/go-dockerclient"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/opencontainers/runtime-spec/specs-go"
@@ -215,7 +213,8 @@ type Executor struct {
 	useCache                       bool
 	removeIntermediateCtrs         bool
 	forceRmIntermediateCtrs        bool
-	imageMap                       map[string]string // Used to map images that we create to handle the AS construct.
+	imageMap                       map[string]string           // Used to map images that we create to handle the AS construct.
+	containerMap                   map[string]*buildah.Builder // Used to map from image names to only-created-for-the-rootfs containers.
 	blobDirectory                  string
 	excludes                       []string
 	unusedArgs                     map[string]struct{}
@@ -496,6 +495,8 @@ func (s *StageExecutor) Copy(excludes []string, copies ...imagebuilder.Copy) err
 			} else if len(copy.From) > 0 {
 				if other, ok := s.executor.stages[copy.From]; ok && other.index < s.index {
 					sources = append(sources, filepath.Join(other.mountPoint, src))
+				} else if builder, ok := s.executor.containerMap[copy.From]; ok {
+					sources = append(sources, filepath.Join(builder.MountPoint, src))
 				} else {
 					return errors.Errorf("the stage %q has not been built", copy.From)
 				}
@@ -654,6 +655,7 @@ func NewExecutor(store storage.Store, options BuildOptions) (*Executor, error) {
 		removeIntermediateCtrs:         options.RemoveIntermediateCtrs,
 		forceRmIntermediateCtrs:        options.ForceRmIntermediateCtrs,
 		imageMap:                       make(map[string]string),
+		containerMap:                   make(map[string]*buildah.Builder),
 		blobDirectory:                  options.BlobDirectory,
 		unusedArgs:                     make(map[string]struct{}),
 	}
@@ -680,18 +682,18 @@ func NewExecutor(store storage.Store, options BuildOptions) (*Executor, error) {
 	return &exec, nil
 }
 
-// Prepare creates a working container based on the specified image, or if one
+// prepare creates a working container based on the specified image, or if one
 // isn't specified, the first argument passed to the first FROM instruction we
 // can find in the stage's parsed tree.
-func (s *StageExecutor) Prepare(ctx context.Context, stage imagebuilder.Stage, from string) error {
+func (s *StageExecutor) prepare(ctx context.Context, stage imagebuilder.Stage, from string, initializeIBConfig, rebase bool) (builder *buildah.Builder, err error) {
 	ib := stage.Builder
 	node := stage.Node
 
 	if from == "" {
 		base, err := ib.From(node)
 		if err != nil {
-			logrus.Debugf("Prepare(node.Children=%#v)", node.Children)
-			return errors.Wrapf(err, "error determining starting point for build")
+			logrus.Debugf("prepare(node.Children=%#v)", node.Children)
+			return nil, errors.Wrapf(err, "error determining starting point for build")
 		}
 		from = base
 	}
@@ -707,9 +709,11 @@ func (s *StageExecutor) Prepare(ctx context.Context, stage imagebuilder.Stage, f
 		}
 	}
 
-	logrus.Debugf("FROM %#v", displayFrom)
-	if !s.executor.quiet {
-		s.executor.log("FROM %s", displayFrom)
+	if initializeIBConfig && rebase {
+		logrus.Debugf("FROM %#v", displayFrom)
+		if !s.executor.quiet {
+			s.executor.log("FROM %s", displayFrom)
+		}
 	}
 
 	builderOptions := buildah.BuilderOptions{
@@ -737,74 +741,79 @@ func (s *StageExecutor) Prepare(ctx context.Context, stage imagebuilder.Stage, f
 	if asImageFound, ok := s.executor.imageMap[from]; ok {
 		builderOptions.FromImage = asImageFound
 	}
-	builder, err := buildah.NewBuilder(ctx, s.executor.store, builderOptions)
-	if err != nil {
-		return errors.Wrapf(err, "error creating build container")
-	}
-
-	volumes := map[string]struct{}{}
-	for _, v := range builder.Volumes() {
-		volumes[v] = struct{}{}
-	}
-	ports := map[docker.Port]struct{}{}
-	for _, p := range builder.Ports() {
-		ports[docker.Port(p)] = struct{}{}
-	}
-	dConfig := docker.Config{
-		Hostname:     builder.Hostname(),
-		Domainname:   builder.Domainname(),
-		User:         builder.User(),
-		Env:          builder.Env(),
-		Cmd:          builder.Cmd(),
-		Image:        from,
-		Volumes:      volumes,
-		WorkingDir:   builder.WorkDir(),
-		Entrypoint:   builder.Entrypoint(),
-		Labels:       builder.Labels(),
-		Shell:        builder.Shell(),
-		StopSignal:   builder.StopSignal(),
-		OnBuild:      builder.OnBuild(),
-		ExposedPorts: ports,
-	}
-	var rootfs *docker.RootFS
-	if builder.Docker.RootFS != nil {
-		rootfs = &docker.RootFS{
-			Type: builder.Docker.RootFS.Type,
-		}
-		for _, id := range builder.Docker.RootFS.DiffIDs {
-			rootfs.Layers = append(rootfs.Layers, id.String())
-		}
-	}
-	dImage := docker.Image{
-		Parent:          builder.FromImage,
-		ContainerConfig: dConfig,
-		Container:       builder.Container,
-		Author:          builder.Maintainer(),
-		Architecture:    builder.Architecture(),
-		RootFS:          rootfs,
-	}
-	dImage.Config = &dImage.ContainerConfig
-	err = ib.FromImage(&dImage, node)
+	builder, err = buildah.NewBuilder(ctx, s.executor.store, builderOptions)
 	if err != nil {
-		if err2 := builder.Delete(); err2 != nil {
-			logrus.Debugf("error deleting container which we failed to update: %v", err2)
+		return nil, errors.Wrapf(err, "error creating build container")
+	}
+
+	if initializeIBConfig {
+		volumes := map[string]struct{}{}
+		for _, v := range builder.Volumes() {
+			volumes[v] = struct{}{}
+		}
+		ports := map[docker.Port]struct{}{}
+		for _, p := range builder.Ports() {
+			ports[docker.Port(p)] = struct{}{}
+		}
+		dConfig := docker.Config{
+			Hostname:     builder.Hostname(),
+			Domainname:   builder.Domainname(),
+			User:         builder.User(),
+			Env:          builder.Env(),
+			Cmd:          builder.Cmd(),
+			Image:        from,
+			Volumes:      volumes,
+			WorkingDir:   builder.WorkDir(),
+			Entrypoint:   builder.Entrypoint(),
+			Labels:       builder.Labels(),
+			Shell:        builder.Shell(),
+			StopSignal:   builder.StopSignal(),
+			OnBuild:      builder.OnBuild(),
+			ExposedPorts: ports,
+		}
+		var rootfs *docker.RootFS
+		if builder.Docker.RootFS != nil {
+			rootfs = &docker.RootFS{
+				Type: builder.Docker.RootFS.Type,
+			}
+			for _, id := range builder.Docker.RootFS.DiffIDs {
+				rootfs.Layers = append(rootfs.Layers, id.String())
+			}
+		}
+		dImage := docker.Image{
+			Parent:          builder.FromImage,
+			ContainerConfig: dConfig,
+			Container:       builder.Container,
+			Author:          builder.Maintainer(),
+			Architecture:    builder.Architecture(),
+			RootFS:          rootfs,
+		}
+		dImage.Config = &dImage.ContainerConfig
+		err = ib.FromImage(&dImage, node)
+		if err != nil {
+			if err2 := builder.Delete(); err2 != nil {
+				logrus.Debugf("error deleting container which we failed to update: %v", err2)
+			}
+			return nil, errors.Wrapf(err, "error updating build context")
 		}
-		return errors.Wrapf(err, "error updating build context")
 	}
 	mountPoint, err := builder.Mount(builder.MountLabel)
 	if err != nil {
 		if err2 := builder.Delete(); err2 != nil {
 			logrus.Debugf("error deleting container which we failed to mount: %v", err2)
 		}
-		return errors.Wrapf(err, "error mounting new container")
+		return nil, errors.Wrapf(err, "error mounting new container")
+	}
+	if rebase {
+		// Make this our "current" working container.
+		s.mountPoint = mountPoint
+		s.builder = builder
+		// Add the top layer of this image to b.topLayers so we can
+		// keep track of them when building with cached images.
+		s.executor.topLayers = append(s.executor.topLayers, builder.TopLayer)
 	}
-	s.mountPoint = mountPoint
-	s.builder = builder
-	// Add the top layer of this image to b.topLayers so we can keep track of them
-	// when building with cached images.
-	s.executor.topLayers = append(s.executor.topLayers, builder.TopLayer)
 	logrus.Debugln("Container ID:", builder.ContainerID)
-	return nil
+	return builder, nil
 }
 
 // Delete deletes the stage's working container, if we have one.
@@ -816,47 +825,118 @@ func (s *StageExecutor) Delete() (err error) {
 	return err
 }
 
-// resolveNameToImageRef creates a types.ImageReference from b.output
+// resolveNameToImageRef creates a types.ImageReference for the output name in local storage
 func (b *Executor) resolveNameToImageRef(output string) (types.ImageReference, error) {
-	var (
-		imageRef types.ImageReference
-		err      error
-	)
-	if output != "" {
-		imageRef, err = alltransports.ParseImageName(output)
+	imageRef, err := alltransports.ParseImageName(output)
+	if err != nil {
+		candidates, _, _, err := util.ResolveName(output, "", b.systemContext, b.store)
 		if err != nil {
-			candidates, _, _, err := util.ResolveName(output, "", b.systemContext, b.store)
-			if err != nil {
-				return nil, errors.Wrapf(err, "error parsing target image name %q", output)
-			}
-			if len(candidates) == 0 {
-				return nil, errors.Errorf("error parsing target image name %q", output)
-			}
-			imageRef2, err2 := is.Transport.ParseStoreReference(b.store, candidates[0])
-			if err2 != nil {
-				return nil, errors.Wrapf(err, "error parsing target image name %q", output)
-			}
-			return imageRef2, nil
+			return nil, errors.Wrapf(err, "error parsing target image name %q", output)
 		}
-		return imageRef, nil
+		if len(candidates) == 0 {
+			return nil, errors.Errorf("error parsing target image name %q", output)
+		}
+		imageRef2, err2 := is.Transport.ParseStoreReference(b.store, candidates[0])
+		if err2 != nil {
+			return nil, errors.Wrapf(err, "error parsing target image name %q", output)
+		}
+		return imageRef2, nil
+	}
+	return imageRef, nil
+}
+
+// stepRequiresCommit indicates whether or not the step should be followed by
+// committing the in-progress container to create an intermediate image.
+func (*StageExecutor) stepRequiresCommit(step *imagebuilder.Step) bool {
+	switch strings.ToUpper(step.Command) {
+	case "ADD", "COPY", "RUN":
+		return true
+	}
+	return false
+}
+
+// getImageRootfs checks for an image matching the passed-in name in local
+// storage.  If it isn't found, it pulls down a copy.  Then, if we don't have a
+// working container root filesystem based on the image, it creates one.  Then
+// it returns that root filesystem's location.
+func (s *StageExecutor) getImageRootfs(ctx context.Context, stage imagebuilder.Stage, image string) (mountPoint string, err error) {
+	if builder, ok := s.executor.containerMap[image]; ok {
+		return builder.MountPoint, nil
 	}
-	imageRef, err = is.Transport.ParseStoreReference(b.store, "@"+stringid.GenerateRandomID())
+	builder, err := s.prepare(ctx, stage, image, false, false)
 	if err != nil {
-		return nil, errors.Wrapf(err, "error parsing reference for image to be written")
+		return "", err
 	}
-	return imageRef, nil
+	s.executor.containerMap[image] = builder
+	return builder.MountPoint, nil
 }
 
 // Execute runs each of the steps in the stage's parsed tree, in turn.
-func (s *StageExecutor) Execute(ctx context.Context, stage imagebuilder.Stage) (imgID string, ref reference.Canonical, err error) {
+func (s *StageExecutor) Execute(ctx context.Context, stage imagebuilder.Stage, base string) (imgID string, ref reference.Canonical, err error) {
 	ib := stage.Builder
-	node := stage.Node
-	checkForLayers := true
-	children := node.Children
-	commitName := s.output
+	checkForLayers := s.executor.layers && s.executor.useCache
+
+	// If the base image's name corresponds to the result of an earlier
+	// stage, substitute that image's ID for the base image's name here.
+	// If not, then go on assuming that it's just a regular image that's
+	// either in local storage, or one that we have to pull from a
+	// registry.
+	if stageImage, isPreviousStage := s.executor.imageMap[base]; isPreviousStage {
+		base = stageImage
+	}
+
+	// Create the (first) working container for this stage.  Reinitializing
+	// the imagebuilder configuration may alter the list of steps we have,
+	// so take a snapshot of them *after* that.
+	if _, err := s.prepare(ctx, stage, base, true, true); err != nil {
+		return "", nil, err
+	}
+	children := stage.Node.Children
+
+	// A helper function to only log "COMMIT" as an explicit step if it's
+	// the very last step of a (possibly multi-stage) build.
+	logCommit := func(output string, instruction int) {
+		if instruction < len(children)-1 || s.index < s.stages-1 {
+			return
+		}
+		commitMessage := "COMMIT"
+		if output != "" {
+			commitMessage = fmt.Sprintf("%s %s", commitMessage, output)
+		}
+		logrus.Debugf(commitMessage)
+		if !s.executor.quiet {
+			s.executor.log(commitMessage)
+		}
+	}
+	logImageID := func(imgID string) {
+		if s.executor.iidfile == "" {
+			fmt.Fprintf(s.executor.out, "--> %s\n", imgID)
+		}
+	}
+
+	if len(children) == 0 {
+		// There are no steps.
+		if s.builder.FromImageID == "" || s.executor.squash {
+			// We either don't have a base image, or we need to
+			// squash the contents of the base image.  Whichever is
+			// the case, we need to commit() to create a new image.
+			logCommit(s.output, -1)
+			if imgID, ref, err = s.commit(ctx, ib, getCreatedBy(nil), s.output); err != nil {
+				return "", nil, errors.Wrapf(err, "error committing base container")
+			}
+		} else {
+			// We don't need to squash the base image, so just
+			// reuse the base image.
+			logCommit(s.output, -1)
+			if imgID, ref, err = s.copyExistingImage(ctx, s.builder.FromImageID, s.output); err != nil {
+				return "", nil, err
+			}
+		}
+		logImageID(imgID)
+	}
 
-	for i, node := range node.Children {
-		// Resolve any arguments in this instruction so that we don't have to.
+	for i, node := range children {
+		// Resolve any arguments in this instruction.
 		step := ib.Step()
 		if err := step.Resolve(node); err != nil {
 			return "", nil, errors.Wrapf(err, "error resolving step %+v", *node)
@@ -868,7 +948,7 @@ func (s *StageExecutor) Execute(ctx context.Context, stage imagebuilder.Stage) (
 
 		// If this instruction declares an argument, remove it from the
 		// set of arguments that we were passed but which we haven't
-		// seen used by the Dockerfile.
+		// yet seen used by the Dockerfile.
 		if step.Command == "arg" {
 			for _, Arg := range step.Args {
 				list := strings.SplitN(Arg, "=", 2)
@@ -884,12 +964,17 @@ func (s *StageExecutor) Execute(ctx context.Context, stage imagebuilder.Stage) (
 		s.copyFrom = s.executor.contextDir
 		for _, n := range step.Flags {
 			if strings.Contains(n, "--from") && (step.Command == "copy" || step.Command == "add") {
+				var mountPoint string
 				arr := strings.Split(n, "=")
-				stage, ok := s.executor.stages[arr[1]]
+				otherStage, ok := s.executor.stages[arr[1]]
 				if !ok {
-					return "", nil, errors.Errorf("%s --from=%s: no stage found with that name", step.Command, arr[1])
+					if mountPoint, err = s.getImageRootfs(ctx, stage, arr[1]); err != nil {
+						return "", nil, errors.Errorf("%s --from=%s: no stage or image found with that name", step.Command, arr[1])
+					}
+				} else {
+					mountPoint = otherStage.mountPoint
 				}
-				s.copyFrom = stage.mountPoint
+				s.copyFrom = mountPoint
 				break
 			}
 		}
@@ -903,101 +988,159 @@ func (s *StageExecutor) Execute(ctx context.Context, stage imagebuilder.Stage) (
 			noRunsRemaining = !ib.RequiresStart(&parser.Node{Children: children[i+1:]})
 		}
 
-		// If we're doing a single-layer build and not looking to take
-		// shortcuts using the cache, make a note of the instruction,
-		// process it, and then move on to the next instruction.
-		if !s.executor.layers && s.executor.useCache {
+		// If we're doing a single-layer build, just process the
+		// instruction.
+		if !s.executor.layers {
 			err := ib.Run(step, s, noRunsRemaining)
 			if err != nil {
-				return "", nil, errors.Wrapf(err, "error building at step %+v", *step)
+				logrus.Debugf("%v", errors.Wrapf(err, "error building at step %+v", *step))
+				return "", nil, errors.Wrapf(err, "error building at STEP \"%s\"", step.Message)
+			}
+			if i < len(children)-1 {
+				// There are still more instructions to process
+				// for this stage.  Make a note of the
+				// instruction in the history that we'll write
+				// for the image when we eventually commit it.
+				now := time.Now()
+				s.builder.AddPrependedEmptyLayer(&now, getCreatedBy(node), "", "")
+				continue
+			} else {
+				// This is the last instruction for this stage,
+				// so we should commit this container to create
+				// an image.
+				logCommit(s.output, i)
+				imgID, ref, err = s.commit(ctx, ib, getCreatedBy(node), s.output)
+				if err != nil {
+					return "", nil, errors.Wrapf(err, "error committing container for step %+v", *step)
+				}
+				logImageID(imgID)
+				break
 			}
-			continue
-		}
-
-		if i < len(children)-1 {
-			commitName = ""
-		} else {
-			commitName = s.output
 		}
 
-		// TODO: this makes the tests happy, but it shouldn't be
-		// necessary unless this is the final stage.
-		commitName = s.executor.output
-
+		// We're in a multi-layered build.
 		var (
-			cacheID string
-			err     error
+			commitName string
+			cacheID    string
+			err        error
+			rebase     bool
 		)
 
+		// If we have to commit for this instruction, only assign the
+		// stage's configured output name to the last layer.
+		if i == len(children)-1 {
+			commitName = s.output
+		}
+
 		// If we're using the cache, and we've managed to stick with
 		// cached images so far, look for one that matches what we
 		// expect to produce for this instruction.
-		if checkForLayers && s.executor.useCache {
+		// Only check at steps where we commit, so that we don't
+		// abandon the cache at this step just because we can't find an
+		// image with a history entry in it that we wouldn't have
+		// committed.
+		if checkForLayers && (s.stepRequiresCommit(step) || i == len(children)-1) && !(s.executor.squash && i == len(children)-1 && s.index == s.stages-1) {
 			cacheID, err = s.layerExists(ctx, node, children[:i])
 			if err != nil {
 				return "", nil, errors.Wrap(err, "error checking if cached image exists from a previous build")
 			}
-		}
-		if cacheID != "" {
-			fmt.Fprintf(s.executor.out, "--> Using cache %s\n", cacheID)
-		}
-
-		// If a cache is found and we're on the last step, that means
-		// nothing in this phase changed.  Just create a copy of the
-		// existing image and save it with the name that we were going
-		// to assign to the one that we were building, and make sure
-		// that the builder's root fs matches it.
-		if cacheID != "" && i == len(children)-1 {
-			if imgID, ref, err = s.copyExistingImage(ctx, cacheID, commitName); err != nil {
-				return "", nil, err
+			if cacheID != "" {
+				// Note the cache hit.
+				fmt.Fprintf(s.executor.out, "--> Using cache %s\n", cacheID)
+			} else {
+				// We're not going to find any more cache hits.
+				checkForLayers = false
 			}
-			break
 		}
 
-		// If we didn't find a cached step that we could just reuse,
-		// process the instruction and commit the layer.
-		if cacheID == "" || !checkForLayers {
-			checkForLayers = false
-			err := ib.Run(step, s, noRunsRemaining)
-			if err != nil {
-				return "", nil, errors.Wrapf(err, "error building at step %+v", *step)
+		if cacheID != "" {
+			// A suitable cached image was found, so just reuse it.
+			// If we need to name the resulting image because it's
+			// the last step in this stage, add the name to the
+			// image.
+			imgID = cacheID
+			if commitName != "" && (s.stepRequiresCommit(step) || i == len(children)-1) {
+				logCommit(s.output, i)
+				if imgID, ref, err = s.copyExistingImage(ctx, cacheID, commitName); err != nil {
+					return "", nil, err
+				}
+				logImageID(imgID)
 			}
-		}
-
-		// Commit if no cache is found
-		if cacheID == "" {
-			imgID, ref, err = s.Commit(ctx, ib, getCreatedBy(node), commitName)
+			// Update our working container to be based off of the
+			// cached image, in case we need to read content from
+			// its root filesystem.
+			rebase = true
+		} else {
+			// If we didn't find a cached image that we could just reuse,
+			// process the instruction directly.
+			err := ib.Run(step, s, noRunsRemaining)
 			if err != nil {
-				return "", nil, errors.Wrapf(err, "error committing container for step %+v", *step)
+				logrus.Debugf("%v", errors.Wrapf(err, "error building at step %+v", *step))
+				return "", nil, errors.Wrapf(err, "error building at STEP \"%s\"", step.Message)
 			}
-			if i == len(children)-1 {
-				s.executor.log("COMMIT %s", commitName)
+			if s.stepRequiresCommit(step) || i == len(children)-1 {
+				// Either this is the last instruction, or
+				// there are more instructions and we need to
+				// create a layer from this one before
+				// continuing.
+				// TODO: only commit for the last instruction
+				// case if we need to use this stage's image as
+				// a base image later, or if we're the final
+				// stage.
+				logCommit(s.output, i)
+				imgID, ref, err = s.commit(ctx, ib, getCreatedBy(node), commitName)
+				if err != nil {
+					return "", nil, errors.Wrapf(err, "error committing container for step %+v", *step)
+				}
+				logImageID(imgID)
+				// We only need to build a new container rootfs
+				// using this image if we plan on making
+				// further changes to it.  Subsequent stages
+				// that just want to use the rootfs as a source
+				// for COPY or ADD will be content with what we
+				// already have.
+				rebase = i < len(children)-1
+			} else {
+				// There are still more instructions to process
+				// for this stage, and we don't need to commit
+				// here.  Make a note of the instruction in the
+				// history for the next commit.
+				now := time.Now()
+				s.builder.AddPrependedEmptyLayer(&now, getCreatedBy(node), "", "")
 			}
-		} else {
-			// If we did find a cache, reuse the cached image's ID
-			// as the basis for the container for the next step.
-			imgID = cacheID
 		}
 
-		// Prepare for the next step with imgID as the new base image.
-		if i < len(children)-1 {
+		if rebase {
+			// Since we either committed the working container or
+			// are about to replace it with one based on a cached
+			// image, add the current working container's ID to the
+			// list of successful intermediate containers that
+			// we'll clean up later.
 			s.containerIDs = append(s.containerIDs, s.builder.ContainerID)
-			if err := s.Prepare(ctx, stage, imgID); err != nil {
+
+			// Prepare for the next step or subsequent phases by
+			// creating a new working container with the
+			// just-committed or updated cached image as its new
+			// base image.
+			// TODO: only create a new container if we know that
+			// we'll need the updated root filesystem.
+			if _, err := s.prepare(ctx, stage, imgID, false, true); err != nil {
 				return "", nil, errors.Wrap(err, "error preparing container for next step")
 			}
 		}
 	}
 
-	if s.executor.layers { // print out the final imageID if we're using layers flag
-		fmt.Fprintf(s.executor.out, "--> %s\n", imgID)
-	}
-
 	return imgID, ref, nil
 }
 
 // copyExistingImage creates a copy of an image already in the store
 func (s *StageExecutor) copyExistingImage(ctx context.Context, cacheID, output string) (string, reference.Canonical, error) {
-	// Get the destination Image Reference
+	// If we don't need to attach a name to the image, just return the cache ID.
+	if output == "" {
+		return cacheID, nil, nil
+	}
+
+	// Get the destination image reference.
 	dest, err := s.executor.resolveNameToImageRef(output)
 	if err != nil {
 		return "", nil, err
@@ -1026,7 +1169,6 @@ func (s *StageExecutor) copyExistingImage(ctx context.Context, cacheID, output s
 	if err != nil {
 		return "", nil, errors.Wrapf(err, "error locating new copy of image %q (i.e., %q)", cacheID, transports.ImageName(dest))
 	}
-	s.executor.log("COMMIT %s", s.output)
 	var ref reference.Canonical
 	if dref := dest.DockerReference(); dref != nil {
 		if ref, err = reference.WithDigest(dref, manifestDigest); err != nil {
@@ -1094,6 +1236,9 @@ func (b *Executor) getImageHistory(ctx context.Context, imageID string) ([]v1.Hi
 
 // getCreatedBy returns the command the image at node will be created by.
 func getCreatedBy(node *parser.Node) string {
+	if node == nil {
+		return "/bin/sh"
+	}
 	if node.Value == "run" {
 		return "/bin/sh -c " + node.Original[4:]
 	}
@@ -1201,12 +1346,16 @@ func urlContentModified(url string, historyTime *time.Time) (bool, error) {
 	return true, nil
 }
 
-// Commit writes the container's contents to an image, using a passed-in tag as
+// commit writes the container's contents to an image, using a passed-in tag as
 // the name if there is one, generating a unique ID-based one otherwise.
-func (s *StageExecutor) Commit(ctx context.Context, ib *imagebuilder.Builder, createdBy, output string) (string, reference.Canonical, error) {
-	imageRef, err := s.executor.resolveNameToImageRef(output)
-	if err != nil {
-		return "", nil, err
+func (s *StageExecutor) commit(ctx context.Context, ib *imagebuilder.Builder, createdBy, output string) (string, reference.Canonical, error) {
+	var imageRef types.ImageReference
+	if output != "" {
+		imageRef2, err := s.executor.resolveNameToImageRef(output)
+		if err != nil {
+			return "", nil, err
+		}
+		imageRef = imageRef2
 	}
 
 	if ib.Author != "" {
@@ -1274,14 +1423,8 @@ func (s *StageExecutor) Commit(ctx context.Context, ib *imagebuilder.Builder, cr
 	if imageRef != nil {
 		logName := transports.ImageName(imageRef)
 		logrus.Debugf("COMMIT %q", logName)
-		if !s.executor.quiet && !s.executor.layers && s.executor.useCache {
-			s.executor.log("COMMIT %s", logName)
-		}
 	} else {
 		logrus.Debugf("COMMIT")
-		if !s.executor.quiet && !s.executor.layers && s.executor.useCache {
-			s.executor.log("COMMIT")
-		}
 	}
 	writer := s.executor.reportWriter
 	if s.executor.layers || !s.executor.useCache {
@@ -1294,7 +1437,6 @@ func (s *StageExecutor) Commit(ctx context.Context, ib *imagebuilder.Builder, cr
 		ReportWriter:          writer,
 		PreferredManifestType: s.executor.outputFormat,
 		SystemContext:         s.executor.systemContext,
-		IIDFile:               s.executor.iidfile,
 		Squash:                s.executor.squash,
 		BlobDirectory:         s.executor.blobDirectory,
 		Parent:                s.builder.FromImageID,
@@ -1303,13 +1445,12 @@ func (s *StageExecutor) Commit(ctx context.Context, ib *imagebuilder.Builder, cr
 	if err != nil {
 		return "", nil, err
 	}
-	if options.IIDFile == "" && imgID != "" {
-		fmt.Fprintf(s.executor.out, "--> %s\n", imgID)
-	}
 	var ref reference.Canonical
-	if dref := imageRef.DockerReference(); dref != nil {
-		if ref, err = reference.WithDigest(dref, manifestDigest); err != nil {
-			return "", nil, errors.Wrapf(err, "error computing canonical reference for new image %q", imgID)
+	if imageRef != nil {
+		if dref := imageRef.DockerReference(); dref != nil {
+			if ref, err = reference.WithDigest(dref, manifestDigest); err != nil {
+				return "", nil, errors.Wrapf(err, "error computing canonical reference for new image %q", imgID)
+			}
 		}
 	}
 	return imgID, ref, nil
@@ -1321,10 +1462,7 @@ func (b *Executor) Build(ctx context.Context, stages imagebuilder.Stages) (image
 	if len(stages) == 0 {
 		return "", nil, errors.New("error building: no stages to build")
 	}
-	var (
-		stageExecutor *StageExecutor
-		cleanupImages []string
-	)
+	var cleanupImages []string
 	cleanupStages := make(map[int]*StageExecutor)
 
 	cleanup := func() error {
@@ -1339,6 +1477,14 @@ func (b *Executor) Build(ctx context.Context, stages imagebuilder.Stages) (image
 			}
 		}
 		cleanupStages = nil
+		// Clean up any builders that we used to get data from images.
+		for _, builder := range b.containerMap {
+			if err := builder.Delete(); err != nil {
+				logrus.Debugf("Failed to cleanup image containers: %v", err)
+				lastErr = err
+			}
+		}
+		b.containerMap = nil
 		// Clean up any intermediate containers associated with stages,
 		// since we're not keeping them for debugging.
 		if b.removeIntermediateCtrs {
@@ -1382,37 +1528,44 @@ func (b *Executor) Build(ctx context.Context, stages imagebuilder.Stages) (image
 			output = b.output
 		}
 
-		stageExecutor = b.startStage(stage.Name, stage.Position, len(stages), base, output)
-		if err := stageExecutor.Prepare(ctx, stage, base); err != nil {
-			return "", nil, err
-		}
+		stageExecutor := b.startStage(stage.Name, stage.Position, len(stages), base, output)
 
-		// Always remove the intermediate/build containers, even if the build was unsuccessful.
-		// If building with layers, remove all intermediate/build containers if b.forceRmIntermediateCtrs
-		// is true.
+		// If this a single-layer build, or if it's a multi-layered
+		// build and b.forceRmIntermediateCtrs is set, make sure we
+		// remove the intermediate/build containers, regardless of
+		// whether or not the stage's build fails.
 		if b.forceRmIntermediateCtrs || !b.layers {
 			cleanupStages[stage.Position] = stageExecutor
 		}
-		if imageID, ref, err = stageExecutor.Execute(ctx, stage); err != nil {
+
+		// Build this stage.
+		if imageID, ref, err = stageExecutor.Execute(ctx, stage, base); err != nil {
 			lastErr = err
 		}
 		if lastErr != nil {
 			return "", nil, lastErr
 		}
-		if !b.forceRmIntermediateCtrs && b.removeIntermediateCtrs {
+
+		// The stage succeeded, so remove its build container if we're
+		// told to delete successful intermediate/build containers for
+		// multi-layered builds.
+		if b.removeIntermediateCtrs {
 			cleanupStages[stage.Position] = stageExecutor
 		}
 
-		// If this is an intermediate stage, make a note to remove its
-		// image later.
-		if _, err := strconv.Atoi(stage.Name); err != nil {
-			if imageID, ref, err = stageExecutor.Commit(ctx, stages[stageIndex].Builder, "", output); err != nil {
-				return "", nil, err
-			}
+		// If this is an intermediate stage, make a note of the ID, so
+		// that we can look it up later.
+		if stageIndex < len(stages)-1 {
 			b.imageMap[stage.Name] = imageID
-			cleanupImages = append(cleanupImages, imageID)
+			// We're not populating the cache with intermediate
+			// images, so add this one to the list of images that
+			// we'll remove later.
+			if !b.layers {
+				cleanupImages = append(cleanupImages, imageID)
+			}
 		}
 	}
+
 	if len(b.unusedArgs) > 0 {
 		unusedList := make([]string, 0, len(b.unusedArgs))
 		for k := range b.unusedArgs {
@@ -1422,25 +1575,16 @@ func (b *Executor) Build(ctx context.Context, stages imagebuilder.Stages) (image
 		fmt.Fprintf(b.out, "[Warning] one or more build args were not consumed: %v\n", unusedList)
 	}
 
-	// Check if we have a one line Dockerfile (i.e., single phase, no
-	// actual steps) making layers irrelevant, or the user told us to
-	// ignore layers.
-	singleLineDockerfile := (len(stages) < 2 && len(stages[0].Node.Children) < 1)
-	ignoreLayers := singleLineDockerfile || !b.layers && b.useCache
-
-	if ignoreLayers {
-		if imageID, ref, err = stageExecutor.Commit(ctx, stages[len(stages)-1].Builder, "", b.output); err != nil {
-			return "", nil, err
-		}
-		if singleLineDockerfile {
-			b.log("COMMIT %s", ref)
-		}
-	}
-
 	if err := cleanup(); err != nil {
 		return "", nil, err
 	}
 
+	if b.iidfile != "" {
+		if err = ioutil.WriteFile(b.iidfile, []byte(imageID), 0644); err != nil {
+			return imageID, ref, errors.Wrapf(err, "failed to write image ID to file %q", b.iidfile)
+		}
+	}
+
 	return imageID, ref, nil
 }
 
@@ -1516,8 +1660,6 @@ func BuildDockerfiles(ctx context.Context, store storage.Store, options BuildOpt
 		dockerfiles = append(dockerfiles, data)
 	}
 
-	dockerfiles = processCopyFrom(dockerfiles)
-
 	mainNode, err := imagebuilder.ParseDockerfile(dockerfiles[0])
 	if err != nil {
 		return "", nil, errors.Wrapf(err, "error parsing main Dockerfile")
@@ -1548,79 +1690,6 @@ func BuildDockerfiles(ctx context.Context, store storage.Store, options BuildOpt
 	return exec.Build(ctx, stages)
 }
 
-// processCopyFrom goes through the Dockerfiles and handles any 'COPY --from' instances
-// prepending a new FROM statement the Dockerfile that do not already have a corresponding
-// FROM command within them.
-func processCopyFrom(dockerfiles []io.ReadCloser) []io.ReadCloser {
-	var newDockerfiles []io.ReadCloser
-	// fromMap contains the names of the images seen in a FROM
-	// line in the Dockerfiles.  The boolean value just completes the map object.
-	fromMap := make(map[string]bool)
-	// asMap contains the names of the images seen after a "FROM image AS"
-	// line in the Dockefiles.  The boolean value just completes the map object.
-	asMap := make(map[string]bool)
-
-	copyRE := regexp.MustCompile(`\s*COPY\s+--from=`)
-	fromRE := regexp.MustCompile(`\s*FROM\s+`)
-	asRE := regexp.MustCompile(`(?i)\s+as\s+`)
-	for _, dfile := range dockerfiles {
-		if dfileBinary, err := ioutil.ReadAll(dfile); err == nil {
-			dfileString := fmt.Sprintf("%s", dfileBinary)
-			copyFromContent := copyRE.Split(dfileString, -1)
-			// no "COPY --from=", just continue
-			if len(copyFromContent) < 2 {
-				newDockerfiles = append(newDockerfiles, ioutil.NopCloser(strings.NewReader(dfileString)))
-				continue
-			}
-			// Load all image names in our Dockerfiles into a map
-			// for easy reference later.
-			fromContent := fromRE.Split(dfileString, -1)
-			for i := 0; i < len(fromContent); i++ {
-				imageName := strings.Split(fromContent[i], " ")
-				if len(imageName) > 0 {
-					finalImage := strings.Split(imageName[0], "\n")
-					if finalImage[0] != "" {
-						fromMap[strings.TrimSpace(finalImage[0])] = true
-					}
-				}
-			}
-			logrus.Debug("fromMap: ", fromMap)
-
-			// Load all image names associated with an 'as' or 'AS' in
-			// our Dockerfiles into a map for easy reference later.
-			asContent := asRE.Split(dfileString, -1)
-			// Skip the first entry in the array as it's stuff before
-			// the " as " and we don't care.
-			for i := 1; i < len(asContent); i++ {
-				asName := strings.Split(asContent[i], " ")
-				if len(asName) > 0 {
-					finalAsImage := strings.Split(asName[0], "\n")
-					if finalAsImage[0] != "" {
-						asMap[strings.TrimSpace(finalAsImage[0])] = true
-					}
-				}
-			}
-			logrus.Debug("asMap: ", asMap)
-
-			for i := 1; i < len(copyFromContent); i++ {
-				fromArray := strings.Split(copyFromContent[i], " ")
-				// If the image isn't a stage number or already declared,
-				// add a FROM statement for it to the top of our Dockerfile.
-				trimmedFrom := strings.TrimSpace(fromArray[0])
-				_, okFrom := fromMap[trimmedFrom]
-				_, okAs := asMap[trimmedFrom]
-				_, err := strconv.Atoi(trimmedFrom)
-				if !okFrom && !okAs && err != nil {
-					from := "FROM " + trimmedFrom
-					newDockerfiles = append(newDockerfiles, ioutil.NopCloser(strings.NewReader(from)))
-				}
-			}
-			newDockerfiles = append(newDockerfiles, ioutil.NopCloser(strings.NewReader(dfileString)))
-		} // End if dfileBinary, err := ioutil.ReadAll(dfile); err == nil
-	} // End for _, dfile := range dockerfiles {
-	return newDockerfiles
-}
-
 // deleteSuccessfulIntermediateCtrs goes through the container IDs in each
 // stage's containerIDs list and deletes the containers associated with those
 // IDs.
diff --git a/vendor/github.com/containers/buildah/imagebuildah/util.go b/vendor/github.com/containers/buildah/imagebuildah/util.go
index 35dc5438a..f982fcebf 100644
--- a/vendor/github.com/containers/buildah/imagebuildah/util.go
+++ b/vendor/github.com/containers/buildah/imagebuildah/util.go
@@ -105,6 +105,18 @@ func TempDirForURL(dir, prefix, url string) (name string, subdir string, err err
 	return "", "", errors.Errorf("unreachable code reached")
 }
 
+func dedupeStringSlice(slice []string) []string {
+	done := make([]string, 0, len(slice))
+	m := make(map[string]struct{})
+	for _, s := range slice {
+		if _, present := m[s]; !present {
+			m[s] = struct{}{}
+			done = append(done, s)
+		}
+	}
+	return done
+}
+
 // InitReexec is a wrapper for buildah.InitReexec().  It should be called at
 // the start of main(), and if it returns true, main() should return
 // immediately.
diff --git a/vendor/github.com/containers/buildah/info.go b/vendor/github.com/containers/buildah/info.go
index 7c73da87e..32b54f257 100644
--- a/vendor/github.com/containers/buildah/info.go
+++ b/vendor/github.com/containers/buildah/info.go
@@ -11,7 +11,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/containers/buildah/unshare"
+	"github.com/containers/buildah/pkg/unshare"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/system"
 	"github.com/sirupsen/logrus"
diff --git a/vendor/github.com/containers/buildah/pkg/cli/common.go b/vendor/github.com/containers/buildah/pkg/cli/common.go
index da07545c7..6c4d14303 100644
--- a/vendor/github.com/containers/buildah/pkg/cli/common.go
+++ b/vendor/github.com/containers/buildah/pkg/cli/common.go
@@ -86,6 +86,9 @@ type FromAndBudResults struct {
 	CPUSetCPUs   string
 	CPUSetMems   string
 	CPUShares    uint64
+	DNSSearch    []string
+	DNSServers   []string
+	DNSOptions   []string
 	Isolation    string
 	Memory       string
 	MemorySwap   string
@@ -132,9 +135,9 @@ func GetLayerFlags(flags *LayerResults) pflag.FlagSet {
 // GetBudFlags returns common bud flags
 func GetBudFlags(flags *BudResults) pflag.FlagSet {
 	fs := pflag.FlagSet{}
-	fs.StringSliceVar(&flags.Annotation, "annotation", []string{}, "Set metadata for an image (default [])")
+	fs.StringArrayVar(&flags.Annotation, "annotation", []string{}, "Set metadata for an image (default [])")
 	fs.StringVar(&flags.Authfile, "authfile", "", "path of the authentication file. Default is ${XDG_RUNTIME_DIR}/containers/auth.json")
-	fs.StringSliceVar(&flags.BuildArg, "build-arg", []string{}, "`argument=value` to supply to the builder")
+	fs.StringArrayVar(&flags.BuildArg, "build-arg", []string{}, "`argument=value` to supply to the builder")
 	fs.StringVar(&flags.CacheFrom, "cache-from", "", "Images to utilise as potential cache sources. The build process does not currently support caching so this is a NOOP.")
 	fs.StringVar(&flags.CertDir, "cert-dir", "", "use certificates at the specified path to access the registry")
 	fs.BoolVar(&flags.Compress, "compress", false, "This is legacy option, which has no effect on the image")
@@ -144,7 +147,7 @@ func GetBudFlags(flags *BudResults) pflag.FlagSet {
 	fs.StringSliceVarP(&flags.File, "file", "f", []string{}, "`pathname or URL` of a Dockerfile")
 	fs.StringVar(&flags.Format, "format", DefaultFormat(), "`format` of the built image's manifest and metadata. Use BUILDAH_FORMAT environment variable to override.")
 	fs.StringVar(&flags.Iidfile, "iidfile", "", "`file` to write the image ID to")
-	fs.StringSliceVar(&flags.Label, "label", []string{}, "Set metadata for an image (default [])")
+	fs.StringArrayVar(&flags.Label, "label", []string{}, "Set metadata for an image (default [])")
 	fs.BoolVar(&flags.NoCache, "no-cache", false, "Do not use existing cached images for the container build. Build from the start with a new set of cached layers.")
 	fs.StringVar(&flags.Logfile, "logfile", "", "log to `file` instead of stdout/stderr")
 	fs.IntVar(&flags.Loglevel, "loglevel", 0, "adjust logging level (range from -2 to 3)")
@@ -157,7 +160,7 @@ func GetBudFlags(flags *BudResults) pflag.FlagSet {
 	fs.StringSliceVar(&flags.RuntimeFlags, "runtime-flag", []string{}, "add global flags for the container runtime")
 	fs.StringVar(&flags.SignaturePolicy, "signature-policy", "", "`pathname` of signature policy file (not usually used)")
 	fs.BoolVar(&flags.Squash, "squash", false, "Squash newly built layers into a single new layer.")
-	fs.StringSliceVarP(&flags.Tag, "tag", "t", []string{}, "tagged `name` to apply to the built image")
+	fs.StringArrayVarP(&flags.Tag, "tag", "t", []string{}, "tagged `name` to apply to the built image")
 	fs.StringVar(&flags.Target, "target", "", "set the target build stage to build")
 	fs.BoolVar(&flags.TlsVerify, "tls-verify", true, "require HTTPS and verify certificates when accessing the registry")
 	return fs
@@ -176,10 +179,13 @@ func GetFromAndBudFlags(flags *FromAndBudResults, usernsResults *UserNSResults,
 	fs.Uint64VarP(&flags.CPUShares, "cpu-shares", "c", 0, "CPU shares (relative weight)")
 	fs.StringVar(&flags.CPUSetCPUs, "cpuset-cpus", "", "CPUs in which to allow execution (0-3, 0,1)")
 	fs.StringVar(&flags.CPUSetMems, "cpuset-mems", "", "memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA systems.")
+	fs.StringSliceVar(&flags.DNSSearch, "dns-search", []string{}, "Set custom DNS search domains")
+	fs.StringSliceVar(&flags.DNSServers, "dns", []string{}, "Set custom DNS servers")
+	fs.StringSliceVar(&flags.DNSOptions, "dns-option", []string{}, "Set custom DNS options")
 	fs.StringVar(&flags.Isolation, "isolation", DefaultIsolation(), "`type` of process isolation to use. Use BUILDAH_ISOLATION environment variable to override.")
 	fs.StringVarP(&flags.Memory, "memory", "m", "", "memory limit (format: <number>[<unit>], where unit = b, k, m or g)")
 	fs.StringVar(&flags.MemorySwap, "memory-swap", "", "swap limit equal to memory plus swap: '-1' to enable unlimited swap")
-	fs.StringSliceVar(&flags.SecurityOpt, "security-opt", []string{}, "security options (default [])")
+	fs.StringArrayVar(&flags.SecurityOpt, "security-opt", []string{}, "security options (default [])")
 	fs.StringVar(&flags.ShmSize, "shm-size", "65536k", "size of '/dev/shm'. The format is `<number><unit>`.")
 	fs.StringSliceVar(&flags.Ulimit, "ulimit", []string{}, "ulimit options (default [])")
 	fs.StringSliceVarP(&flags.Volume, "volume", "v", []string{}, "bind mount a volume into the container (default [])")
diff --git a/vendor/github.com/containers/buildah/pkg/parse/parse.go b/vendor/github.com/containers/buildah/pkg/parse/parse.go
index 50318315f..c4e3e4264 100644
--- a/vendor/github.com/containers/buildah/pkg/parse/parse.go
+++ b/vendor/github.com/containers/buildah/pkg/parse/parse.go
@@ -6,7 +6,6 @@ package parse
 
 import (
 	"fmt"
-	"github.com/spf13/cobra"
 	"net"
 	"os"
 	"path/filepath"
@@ -21,6 +20,7 @@ import (
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
 	"golang.org/x/crypto/ssh/terminal"
 	"golang.org/x/sys/unix"
 )
@@ -71,6 +71,11 @@ func CommonBuildOptions(c *cobra.Command) (*buildah.CommonBuildOptions, error) {
 			}
 		}
 	}
+
+	dnsServers, _ := c.Flags().GetStringSlice("dns")
+	dnsSearch, _ := c.Flags().GetStringSlice("dns-search")
+	dnsOptions, _ := c.Flags().GetStringSlice("dns-option")
+
 	if _, err := units.FromHumanSize(c.Flag("shm-size").Value.String()); err != nil {
 		return nil, errors.Wrapf(err, "invalid --shm-size")
 	}
@@ -90,13 +95,16 @@ func CommonBuildOptions(c *cobra.Command) (*buildah.CommonBuildOptions, error) {
 		CPUSetCPUs:   c.Flag("cpuset-cpus").Value.String(),
 		CPUSetMems:   c.Flag("cpuset-mems").Value.String(),
 		CPUShares:    cpuShares,
+		DNSSearch:    dnsSearch,
+		DNSServers:   dnsServers,
+		DNSOptions:   dnsOptions,
 		Memory:       memoryLimit,
 		MemorySwap:   memorySwap,
 		ShmSize:      c.Flag("shm-size").Value.String(),
 		Ulimit:       append(defaultLimits, ulimit...),
 		Volumes:      volumes,
 	}
-	securityOpts, _ := c.Flags().GetStringSlice("security-opt")
+	securityOpts, _ := c.Flags().GetStringArray("security-opt")
 	if err := parseSecurityOpts(securityOpts, commonOpts); err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/containers/buildah/unshare/unshare.c b/vendor/github.com/containers/buildah/pkg/unshare/unshare.c
index 8eefae41b..67a3e0e4d 100644
--- a/vendor/github.com/containers/buildah/unshare/unshare.c
+++ b/vendor/github.com/containers/buildah/pkg/unshare/unshare.c
@@ -39,7 +39,7 @@
 static const char *_max_user_namespaces = "/proc/sys/user/max_user_namespaces";
 static const char *_unprivileged_user_namespaces = "/proc/sys/kernel/unprivileged_userns_clone";
 
-static int _buildah_unshare_parse_envint(const char *envname) {
+static int _containers_unshare_parse_envint(const char *envname) {
 	char *p, *q;
 	long l;
 
@@ -138,7 +138,7 @@ static char **parse_proc_stringlist(const char *list) {
 	return ret;
 }
 
-static int buildah_reexec(void) {
+static int containers_reexec(void) {
 	char **argv, *exename;
 	int fd, mmfd, n_read, n_written;
 	struct stat st;
@@ -196,12 +196,12 @@ static int buildah_reexec(void) {
 	return 0;
 }
 
-void _buildah_unshare(void)
+void _containers_unshare(void)
 {
 	int flags, pidfd, continuefd, n, pgrp, sid, ctty;
 	char buf[2048];
 
-	flags = _buildah_unshare_parse_envint("_Buildah-unshare");
+	flags = _containers_unshare_parse_envint("_Containers-unshare");
 	if (flags == -1) {
 		return;
 	}
@@ -213,7 +213,7 @@ void _buildah_unshare(void)
 			_exit(1);
 		}
 	}
-	pidfd = _buildah_unshare_parse_envint("_Buildah-pid-pipe");
+	pidfd = _containers_unshare_parse_envint("_Containers-pid-pipe");
 	if (pidfd != -1) {
 		snprintf(buf, sizeof(buf), "%llu", (unsigned long long) getpid());
 		size_t size = write(pidfd, buf, strlen(buf));
@@ -223,7 +223,7 @@ void _buildah_unshare(void)
 		}
 		close(pidfd);
 	}
-	continuefd = _buildah_unshare_parse_envint("_Buildah-continue-pipe");
+	continuefd = _containers_unshare_parse_envint("_Containers-continue-pipe");
 	if (continuefd != -1) {
 		n = read(continuefd, buf, sizeof(buf));
 		if (n > 0) {
@@ -232,21 +232,21 @@ void _buildah_unshare(void)
 		}
 		close(continuefd);
 	}
-	sid = _buildah_unshare_parse_envint("_Buildah-setsid");
+	sid = _containers_unshare_parse_envint("_Containers-setsid");
 	if (sid == 1) {
 		if (setsid() == -1) {
 			fprintf(stderr, "Error during setsid: %m\n");
 			_exit(1);
 		}
 	}
-	pgrp = _buildah_unshare_parse_envint("_Buildah-setpgrp");
+	pgrp = _containers_unshare_parse_envint("_Containers-setpgrp");
 	if (pgrp == 1) {
 		if (setpgrp() == -1) {
 			fprintf(stderr, "Error during setpgrp: %m\n");
 			_exit(1);
 		}
 	}
-	ctty = _buildah_unshare_parse_envint("_Buildah-ctty");
+	ctty = _containers_unshare_parse_envint("_Containers-ctty");
 	if (ctty != -1) {
 		if (ioctl(ctty, TIOCSCTTY, 0) == -1) {
 			fprintf(stderr, "Error while setting controlling terminal to %d: %m\n", ctty);
@@ -269,7 +269,7 @@ void _buildah_unshare(void)
 			_exit(1);
 		}
 	}
-	if (buildah_reexec() != 0) {
+	if (containers_reexec() != 0) {
 		_exit(1);
 	}
 	return;
diff --git a/vendor/github.com/containers/buildah/unshare/unshare.go b/vendor/github.com/containers/buildah/pkg/unshare/unshare.go
index 77aee282f..5b2e7d7d1 100644
--- a/vendor/github.com/containers/buildah/unshare/unshare.go
+++ b/vendor/github.com/containers/buildah/pkg/unshare/unshare.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"os/user"
 	"runtime"
 	"strconv"
 	"strings"
@@ -18,6 +19,8 @@ import (
 	"github.com/containers/storage/pkg/reexec"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/syndtr/gocapability/capability"
 )
 
 // Cmd wraps an exec.Cmd created by the reexec package in unshare(), and
@@ -54,7 +57,7 @@ func (c *Cmd) Start() error {
 	if c.Env == nil {
 		c.Env = os.Environ()
 	}
-	c.Env = append(c.Env, fmt.Sprintf("_Buildah-unshare=%d", c.UnshareFlags))
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-unshare=%d", c.UnshareFlags))
 
 	// Please the libpod "rootless" package to find the expected env variables.
 	if os.Geteuid() != 0 {
@@ -67,7 +70,7 @@ func (c *Cmd) Start() error {
 	if err != nil {
 		return errors.Wrapf(err, "error creating pid pipe")
 	}
-	c.Env = append(c.Env, fmt.Sprintf("_Buildah-pid-pipe=%d", len(c.ExtraFiles)+3))
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-pid-pipe=%d", len(c.ExtraFiles)+3))
 	c.ExtraFiles = append(c.ExtraFiles, pidWrite)
 
 	// Create the pipe for letting the child know to proceed.
@@ -77,18 +80,18 @@ func (c *Cmd) Start() error {
 		pidWrite.Close()
 		return errors.Wrapf(err, "error creating pid pipe")
 	}
-	c.Env = append(c.Env, fmt.Sprintf("_Buildah-continue-pipe=%d", len(c.ExtraFiles)+3))
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-continue-pipe=%d", len(c.ExtraFiles)+3))
 	c.ExtraFiles = append(c.ExtraFiles, continueRead)
 
 	// Pass along other instructions.
 	if c.Setsid {
-		c.Env = append(c.Env, "_Buildah-setsid=1")
+		c.Env = append(c.Env, "_Containers-setsid=1")
 	}
 	if c.Setpgrp {
-		c.Env = append(c.Env, "_Buildah-setpgrp=1")
+		c.Env = append(c.Env, "_Containers-setpgrp=1")
 	}
 	if c.Ctty != nil {
-		c.Env = append(c.Env, fmt.Sprintf("_Buildah-ctty=%d", len(c.ExtraFiles)+3))
+		c.Env = append(c.Env, fmt.Sprintf("_Containers-ctty=%d", len(c.ExtraFiles)+3))
 		c.ExtraFiles = append(c.ExtraFiles, c.Ctty)
 	}
 
@@ -306,3 +309,140 @@ func GetRootlessUID() int {
 func RootlessEnv() []string {
 	return append(os.Environ(), UsernsEnvName+"=done")
 }
+
+type Runnable interface {
+	Run() error
+}
+
+func bailOnError(err error, format string, a ...interface{}) {
+	if err != nil {
+		if format != "" {
+			logrus.Errorf("%s: %v", fmt.Sprintf(format, a...), err)
+		} else {
+			logrus.Errorf("%v", err)
+		}
+		os.Exit(1)
+	}
+}
+
+// MaybeReexecUsingUserNamespace re-exec the process in a new namespace
+func MaybeReexecUsingUserNamespace(evenForRoot bool) {
+	// If we've already been through this once, no need to try again.
+	if os.Geteuid() == 0 && IsRootless() {
+		return
+	}
+
+	var uidNum, gidNum uint64
+	// Figure out who we are.
+	me, err := user.Current()
+	if !os.IsNotExist(err) {
+		bailOnError(err, "error determining current user")
+		uidNum, err = strconv.ParseUint(me.Uid, 10, 32)
+		bailOnError(err, "error parsing current UID %s", me.Uid)
+		gidNum, err = strconv.ParseUint(me.Gid, 10, 32)
+		bailOnError(err, "error parsing current GID %s", me.Gid)
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	// ID mappings to use to reexec ourselves.
+	var uidmap, gidmap []specs.LinuxIDMapping
+	if uidNum != 0 || evenForRoot {
+		// Read the set of ID mappings that we're allowed to use.  Each
+		// range in /etc/subuid and /etc/subgid file is a starting host
+		// ID and a range size.
+		uidmap, gidmap, err = util.GetSubIDMappings(me.Username, me.Username)
+		bailOnError(err, "error reading allowed ID mappings")
+		if len(uidmap) == 0 {
+			logrus.Warnf("Found no UID ranges set aside for user %q in /etc/subuid.", me.Username)
+		}
+		if len(gidmap) == 0 {
+			logrus.Warnf("Found no GID ranges set aside for user %q in /etc/subgid.", me.Username)
+		}
+		// Map our UID and GID, then the subuid and subgid ranges,
+		// consecutively, starting at 0, to get the mappings to use for
+		// a copy of ourselves.
+		uidmap = append([]specs.LinuxIDMapping{{HostID: uint32(uidNum), ContainerID: 0, Size: 1}}, uidmap...)
+		gidmap = append([]specs.LinuxIDMapping{{HostID: uint32(gidNum), ContainerID: 0, Size: 1}}, gidmap...)
+		var rangeStart uint32
+		for i := range uidmap {
+			uidmap[i].ContainerID = rangeStart
+			rangeStart += uidmap[i].Size
+		}
+		rangeStart = 0
+		for i := range gidmap {
+			gidmap[i].ContainerID = rangeStart
+			rangeStart += gidmap[i].Size
+		}
+	} else {
+		// If we have CAP_SYS_ADMIN, then we don't need to create a new namespace in order to be able
+		// to use unshare(), so don't bother creating a new user namespace at this point.
+		capabilities, err := capability.NewPid(0)
+		bailOnError(err, "error reading the current capabilities sets")
+		if capabilities.Get(capability.EFFECTIVE, capability.CAP_SYS_ADMIN) {
+			return
+		}
+		// Read the set of ID mappings that we're currently using.
+		uidmap, gidmap, err = util.GetHostIDMappings("")
+		bailOnError(err, "error reading current ID mappings")
+		// Just reuse them.
+		for i := range uidmap {
+			uidmap[i].HostID = uidmap[i].ContainerID
+		}
+		for i := range gidmap {
+			gidmap[i].HostID = gidmap[i].ContainerID
+		}
+	}
+
+	// Unlike most uses of reexec or unshare, we're using a name that
+	// _won't_ be recognized as a registered reexec handler, since we
+	// _want_ to fall through reexec.Init() to the normal main().
+	cmd := Command(append([]string{fmt.Sprintf("%s-in-a-user-namespace", os.Args[0])}, os.Args[1:]...)...)
+
+	// If, somehow, we don't become UID 0 in our child, indicate that the child shouldn't try again.
+	err = os.Setenv(UsernsEnvName, "1")
+	bailOnError(err, "error setting %s=1 in environment", UsernsEnvName)
+
+	// Reuse our stdio.
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	// Set up a new user namespace with the ID mapping.
+	cmd.UnshareFlags = syscall.CLONE_NEWUSER | syscall.CLONE_NEWNS
+	cmd.UseNewuidmap = uidNum != 0
+	cmd.UidMappings = uidmap
+	cmd.UseNewgidmap = uidNum != 0
+	cmd.GidMappings = gidmap
+	cmd.GidMappingsEnableSetgroups = true
+
+	// Finish up.
+	logrus.Debugf("running %+v with environment %+v, UID map %+v, and GID map %+v", cmd.Cmd.Args, os.Environ(), cmd.UidMappings, cmd.GidMappings)
+	ExecRunnable(cmd)
+}
+
+// ExecRunnable runs the specified unshare command, captures its exit status,
+// and exits with the same status.
+func ExecRunnable(cmd Runnable) {
+	if err := cmd.Run(); err != nil {
+		if exitError, ok := errors.Cause(err).(*exec.ExitError); ok {
+			if exitError.ProcessState.Exited() {
+				if waitStatus, ok := exitError.ProcessState.Sys().(syscall.WaitStatus); ok {
+					if waitStatus.Exited() {
+						logrus.Errorf("%v", exitError)
+						os.Exit(waitStatus.ExitStatus())
+					}
+					if waitStatus.Signaled() {
+						logrus.Errorf("%v", exitError)
+						os.Exit(int(waitStatus.Signal()) + 128)
+					}
+				}
+			}
+		}
+		logrus.Errorf("%v", err)
+		logrus.Errorf("(unable to determine exit status)")
+		os.Exit(1)
+	}
+	os.Exit(0)
+}
diff --git a/vendor/github.com/containers/buildah/unshare/unshare_cgo.go b/vendor/github.com/containers/buildah/pkg/unshare/unshare_cgo.go
index 26a0b2c20..b3f8099f6 100644
--- a/vendor/github.com/containers/buildah/unshare/unshare_cgo.go
+++ b/vendor/github.com/containers/buildah/pkg/unshare/unshare_cgo.go
@@ -3,8 +3,8 @@
 package unshare
 
 // #cgo CFLAGS: -Wall
-// extern void _buildah_unshare(void);
+// extern void _containers_unshare(void);
 // void __attribute__((constructor)) init(void) {
-//   _buildah_unshare();
+//   _containers_unshare();
 // }
 import "C"
diff --git a/vendor/github.com/containers/buildah/unshare/unshare_gccgo.go b/vendor/github.com/containers/buildah/pkg/unshare/unshare_gccgo.go
index c4811782a..2f95da7d8 100644
--- a/vendor/github.com/containers/buildah/unshare/unshare_gccgo.go
+++ b/vendor/github.com/containers/buildah/pkg/unshare/unshare_gccgo.go
@@ -3,9 +3,9 @@
 package unshare
 
 // #cgo CFLAGS: -Wall -Wextra
-// extern void _buildah_unshare(void);
+// extern void _containers_unshare(void);
 // void __attribute__((constructor)) init(void) {
-//   _buildah_unshare();
+//   _containers_unshare();
 // }
 import "C"
 
diff --git a/vendor/github.com/containers/buildah/unshare/unshare_unsupported.go b/vendor/github.com/containers/buildah/pkg/unshare/unshare_unsupported.go
index 3336fdad9..d8d5f6f7a 100644
--- a/vendor/github.com/containers/buildah/unshare/unshare_unsupported.go
+++ b/vendor/github.com/containers/buildah/pkg/unshare/unshare_unsupported.go
@@ -25,3 +25,7 @@ func GetRootlessUID() int {
 func RootlessEnv() []string {
 	return append(os.Environ(), UsernsEnvName+"=")
 }
+
+// MaybeReexecUsingUserNamespace re-exec the process in a new namespace
+func MaybeReexecUsingUserNamespace(evenForRoot bool) {
+}
diff --git a/vendor/github.com/containers/buildah/run.go b/vendor/github.com/containers/buildah/run.go
index cd6568b66..5d28644d7 100644
--- a/vendor/github.com/containers/buildah/run.go
+++ b/vendor/github.com/containers/buildah/run.go
@@ -22,13 +22,15 @@ import (
 	"github.com/containers/buildah/bind"
 	"github.com/containers/buildah/chroot"
 	"github.com/containers/buildah/pkg/secrets"
-	"github.com/containers/buildah/unshare"
+	"github.com/containers/buildah/pkg/unshare"
 	"github.com/containers/buildah/util"
 	"github.com/containers/storage/pkg/idtools"
 	"github.com/containers/storage/pkg/ioutils"
 	"github.com/containers/storage/pkg/reexec"
 	"github.com/containers/storage/pkg/stringid"
 	units "github.com/docker/go-units"
+	"github.com/docker/libnetwork/resolvconf"
+	"github.com/docker/libnetwork/types"
 	digest "github.com/opencontainers/go-digest"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/runtime-tools/generate"
@@ -593,13 +595,51 @@ func runSetupVolumeMounts(mountLabel string, volumeMounts []string, optionMounts
 }
 
 // addNetworkConfig copies files from host and sets them up to bind mount into container
-func (b *Builder) addNetworkConfig(rdir, hostPath string, chownOpts *idtools.IDPair) (string, error) {
-	copyFileWithTar := b.copyFileWithTar(chownOpts, nil)
+func (b *Builder) addNetworkConfig(rdir, hostPath string, chownOpts *idtools.IDPair, dnsServers, dnsSearch, dnsOptions []string) (string, error) {
+	stat, err := os.Stat(hostPath)
+	if err != nil {
+		return "", errors.Wrapf(err, "error statting %q for container %q", hostPath, b.ContainerID)
+	}
+	contents, err := ioutil.ReadFile(hostPath)
+	if err != nil {
+		return "", errors.Wrapf(err, "unable to read %s", hostPath)
+	}
+
+	search := resolvconf.GetSearchDomains(contents)
+	nameservers := resolvconf.GetNameservers(contents, types.IP)
+	options := resolvconf.GetOptions(contents)
+
+	if len(dnsSearch) > 0 {
+		search = dnsSearch
+	}
+	if len(dnsServers) != 0 {
+		dns, err := getDNSIP(dnsServers)
+		if err != nil {
+			return "", errors.Wrapf(err, "error getting dns servers")
+		}
+		nameservers = []string{}
+		for _, server := range dns {
+			nameservers = append(nameservers, server.String())
+		}
+	}
+
+	if len(dnsOptions) != 0 {
+		options = dnsOptions
+	}
 
 	cfile := filepath.Join(rdir, filepath.Base(hostPath))
+	if _, err = resolvconf.Build(cfile, nameservers, search, options); err != nil {
+		return "", errors.Wrapf(err, "error building resolv.conf for container %s", b.ContainerID)
+	}
 
-	if err := copyFileWithTar(hostPath, cfile); err != nil {
-		return "", errors.Wrapf(err, "error copying %q for container %q", cfile, b.ContainerID)
+	uid := int(stat.Sys().(*syscall.Stat_t).Uid)
+	gid := int(stat.Sys().(*syscall.Stat_t).Gid)
+	if chownOpts != nil {
+		uid = chownOpts.UID
+		gid = chownOpts.GID
+	}
+	if err = os.Chown(cfile, uid, gid); err != nil {
+		return "", errors.Wrapf(err, "error chowning file %q for container %q", cfile, b.ContainerID)
 	}
 
 	if err := label.Relabel(cfile, b.MountLabel, false); err != nil {
@@ -609,6 +649,17 @@ func (b *Builder) addNetworkConfig(rdir, hostPath string, chownOpts *idtools.IDP
 	return cfile, nil
 }
 
+func getDNSIP(dnsServers []string) (dns []net.IP, err error) {
+	for _, i := range dnsServers {
+		result := net.ParseIP(i)
+		if result == nil {
+			return dns, errors.Errorf("invalid IP address %s", i)
+		}
+		dns = append(dns, result)
+	}
+	return dns, nil
+}
+
 // generateHosts creates a containers hosts file
 func (b *Builder) generateHosts(rdir, hostname string, addHosts []string, chownOpts *idtools.IDPair) (string, error) {
 	hostPath := "/etc/hosts"
@@ -1113,7 +1164,7 @@ func (b *Builder) Run(command []string, options RunOptions) error {
 	}
 
 	if !contains(volumes, "/etc/resolv.conf") {
-		resolvFile, err := b.addNetworkConfig(path, "/etc/resolv.conf", rootIDPair)
+		resolvFile, err := b.addNetworkConfig(path, "/etc/resolv.conf", rootIDPair, b.CommonBuildOpts.DNSServers, b.CommonBuildOpts.DNSSearch, b.CommonBuildOpts.DNSOptions)
 		if err != nil {
 			return err
 		}
diff --git a/vendor/github.com/containers/buildah/vendor.conf b/vendor/github.com/containers/buildah/vendor.conf
index 327de39b2..a77130acb 100644
--- a/vendor/github.com/containers/buildah/vendor.conf
+++ b/vendor/github.com/containers/buildah/vendor.conf
@@ -8,7 +8,7 @@ github.com/vbauerster/mpb v3.3.4
 github.com/mattn/go-isatty v0.0.4
 github.com/VividCortex/ewma v1.1.1
 github.com/boltdb/bolt v1.3.1
-github.com/containers/storage v1.12.1
+github.com/containers/storage v1.12.2
 github.com/docker/distribution 5f6282db7d65e6d72ad7c2cc66310724a57be716
 github.com/docker/docker 54dddadc7d5d89fe0be88f76979f6f6ab0dede83
 github.com/docker/docker-credential-helpers v0.6.1
@@ -65,3 +65,4 @@ github.com/klauspost/cpuid v1.2.0
 github.com/onsi/gomega v1.4.3
 github.com/spf13/cobra v0.0.3
 github.com/spf13/pflag v1.0.3
+github.com/ishidawataru/sctp 07191f837fedd2f13d1ec7b5f885f0f3ec54b1cb
diff --git a/vendor/github.com/docker/libnetwork/resolvconf/README.md b/vendor/github.com/docker/libnetwork/resolvconf/README.md
new file mode 100644
index 000000000..cdda554ba
--- /dev/null
+++ b/vendor/github.com/docker/libnetwork/resolvconf/README.md
@@ -0,0 +1 @@
+Package resolvconf provides utility code to query and update DNS configuration in /etc/resolv.conf
diff --git a/vendor/github.com/docker/libnetwork/resolvconf/dns/resolvconf.go b/vendor/github.com/docker/libnetwork/resolvconf/dns/resolvconf.go
new file mode 100644
index 000000000..e348bc57f
--- /dev/null
+++ b/vendor/github.com/docker/libnetwork/resolvconf/dns/resolvconf.go
@@ -0,0 +1,26 @@
+package dns
+
+import (
+	"regexp"
+)
+
+// IPLocalhost is a regex pattern for IPv4 or IPv6 loopback range.
+const IPLocalhost = `((127\.([0-9]{1,3}\.){2}[0-9]{1,3})|(::1)$)`
+
+// IPv4Localhost is a regex pattern for IPv4 localhost address range.
+const IPv4Localhost = `(127\.([0-9]{1,3}\.){2}[0-9]{1,3})`
+
+var localhostIPRegexp = regexp.MustCompile(IPLocalhost)
+var localhostIPv4Regexp = regexp.MustCompile(IPv4Localhost)
+
+// IsLocalhost returns true if ip matches the localhost IP regular expression.
+// Used for determining if nameserver settings are being passed which are
+// localhost addresses
+func IsLocalhost(ip string) bool {
+	return localhostIPRegexp.MatchString(ip)
+}
+
+// IsIPv4Localhost returns true if ip matches the IPv4 localhost regular expression.
+func IsIPv4Localhost(ip string) bool {
+	return localhostIPv4Regexp.MatchString(ip)
+}
diff --git a/vendor/github.com/docker/libnetwork/resolvconf/resolvconf.go b/vendor/github.com/docker/libnetwork/resolvconf/resolvconf.go
new file mode 100644
index 000000000..23caf7f12
--- /dev/null
+++ b/vendor/github.com/docker/libnetwork/resolvconf/resolvconf.go
@@ -0,0 +1,251 @@
+// Package resolvconf provides utility code to query and update DNS configuration in /etc/resolv.conf
+package resolvconf
+
+import (
+	"bytes"
+	"io/ioutil"
+	"regexp"
+	"strings"
+	"sync"
+
+	"github.com/docker/docker/pkg/ioutils"
+	"github.com/docker/libnetwork/resolvconf/dns"
+	"github.com/docker/libnetwork/types"
+	"github.com/sirupsen/logrus"
+)
+
+const (
+	// DefaultResolvConf points to the default file used for dns configuration on a linux machine
+	DefaultResolvConf = "/etc/resolv.conf"
+)
+
+var (
+	// Note: the default IPv4 & IPv6 resolvers are set to Google's Public DNS
+	defaultIPv4Dns = []string{"nameserver 8.8.8.8", "nameserver 8.8.4.4"}
+	defaultIPv6Dns = []string{"nameserver 2001:4860:4860::8888", "nameserver 2001:4860:4860::8844"}
+	ipv4NumBlock   = `(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)`
+	ipv4Address    = `(` + ipv4NumBlock + `\.){3}` + ipv4NumBlock
+	// This is not an IPv6 address verifier as it will accept a super-set of IPv6, and also
+	// will *not match* IPv4-Embedded IPv6 Addresses (RFC6052), but that and other variants
+	// -- e.g. other link-local types -- either won't work in containers or are unnecessary.
+	// For readability and sufficiency for Docker purposes this seemed more reasonable than a
+	// 1000+ character regexp with exact and complete IPv6 validation
+	ipv6Address = `([0-9A-Fa-f]{0,4}:){2,7}([0-9A-Fa-f]{0,4})(%\w+)?`
+
+	localhostNSRegexp = regexp.MustCompile(`(?m)^nameserver\s+` + dns.IPLocalhost + `\s*\n*`)
+	nsIPv6Regexp      = regexp.MustCompile(`(?m)^nameserver\s+` + ipv6Address + `\s*\n*`)
+	nsRegexp          = regexp.MustCompile(`^\s*nameserver\s*((` + ipv4Address + `)|(` + ipv6Address + `))\s*$`)
+	nsIPv6Regexpmatch = regexp.MustCompile(`^\s*nameserver\s*((` + ipv6Address + `))\s*$`)
+	nsIPv4Regexpmatch = regexp.MustCompile(`^\s*nameserver\s*((` + ipv4Address + `))\s*$`)
+	searchRegexp      = regexp.MustCompile(`^\s*search\s*(([^\s]+\s*)*)$`)
+	optionsRegexp     = regexp.MustCompile(`^\s*options\s*(([^\s]+\s*)*)$`)
+)
+
+var lastModified struct {
+	sync.Mutex
+	sha256   string
+	contents []byte
+}
+
+// File contains the resolv.conf content and its hash
+type File struct {
+	Content []byte
+	Hash    string
+}
+
+// Get returns the contents of /etc/resolv.conf and its hash
+func Get() (*File, error) {
+	return GetSpecific(DefaultResolvConf)
+}
+
+// GetSpecific returns the contents of the user specified resolv.conf file and its hash
+func GetSpecific(path string) (*File, error) {
+	resolv, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	hash, err := ioutils.HashData(bytes.NewReader(resolv))
+	if err != nil {
+		return nil, err
+	}
+	return &File{Content: resolv, Hash: hash}, nil
+}
+
+// GetIfChanged retrieves the host /etc/resolv.conf file, checks against the last hash
+// and, if modified since last check, returns the bytes and new hash.
+// This feature is used by the resolv.conf updater for containers
+func GetIfChanged() (*File, error) {
+	lastModified.Lock()
+	defer lastModified.Unlock()
+
+	resolv, err := ioutil.ReadFile("/etc/resolv.conf")
+	if err != nil {
+		return nil, err
+	}
+	newHash, err := ioutils.HashData(bytes.NewReader(resolv))
+	if err != nil {
+		return nil, err
+	}
+	if lastModified.sha256 != newHash {
+		lastModified.sha256 = newHash
+		lastModified.contents = resolv
+		return &File{Content: resolv, Hash: newHash}, nil
+	}
+	// nothing changed, so return no data
+	return nil, nil
+}
+
+// GetLastModified retrieves the last used contents and hash of the host resolv.conf.
+// Used by containers updating on restart
+func GetLastModified() *File {
+	lastModified.Lock()
+	defer lastModified.Unlock()
+
+	return &File{Content: lastModified.contents, Hash: lastModified.sha256}
+}
+
+// FilterResolvDNS cleans up the config in resolvConf.  It has two main jobs:
+// 1. It looks for localhost (127.*|::1) entries in the provided
+//    resolv.conf, removing local nameserver entries, and, if the resulting
+//    cleaned config has no defined nameservers left, adds default DNS entries
+// 2. Given the caller provides the enable/disable state of IPv6, the filter
+//    code will remove all IPv6 nameservers if it is not enabled for containers
+//
+func FilterResolvDNS(resolvConf []byte, ipv6Enabled bool) (*File, error) {
+	cleanedResolvConf := localhostNSRegexp.ReplaceAll(resolvConf, []byte{})
+	// if IPv6 is not enabled, also clean out any IPv6 address nameserver
+	if !ipv6Enabled {
+		cleanedResolvConf = nsIPv6Regexp.ReplaceAll(cleanedResolvConf, []byte{})
+	}
+	// if the resulting resolvConf has no more nameservers defined, add appropriate
+	// default DNS servers for IPv4 and (optionally) IPv6
+	if len(GetNameservers(cleanedResolvConf, types.IP)) == 0 {
+		logrus.Infof("No non-localhost DNS nameservers are left in resolv.conf. Using default external servers: %v", defaultIPv4Dns)
+		dns := defaultIPv4Dns
+		if ipv6Enabled {
+			logrus.Infof("IPv6 enabled; Adding default IPv6 external servers: %v", defaultIPv6Dns)
+			dns = append(dns, defaultIPv6Dns...)
+		}
+		cleanedResolvConf = append(cleanedResolvConf, []byte("\n"+strings.Join(dns, "\n"))...)
+	}
+	hash, err := ioutils.HashData(bytes.NewReader(cleanedResolvConf))
+	if err != nil {
+		return nil, err
+	}
+	return &File{Content: cleanedResolvConf, Hash: hash}, nil
+}
+
+// getLines parses input into lines and strips away comments.
+func getLines(input []byte, commentMarker []byte) [][]byte {
+	lines := bytes.Split(input, []byte("\n"))
+	var output [][]byte
+	for _, currentLine := range lines {
+		var commentIndex = bytes.Index(currentLine, commentMarker)
+		if commentIndex == -1 {
+			output = append(output, currentLine)
+		} else {
+			output = append(output, currentLine[:commentIndex])
+		}
+	}
+	return output
+}
+
+// GetNameservers returns nameservers (if any) listed in /etc/resolv.conf
+func GetNameservers(resolvConf []byte, kind int) []string {
+	nameservers := []string{}
+	for _, line := range getLines(resolvConf, []byte("#")) {
+		var ns [][]byte
+		if kind == types.IP {
+			ns = nsRegexp.FindSubmatch(line)
+		} else if kind == types.IPv4 {
+			ns = nsIPv4Regexpmatch.FindSubmatch(line)
+		} else if kind == types.IPv6 {
+			ns = nsIPv6Regexpmatch.FindSubmatch(line)
+		}
+		if len(ns) > 0 {
+			nameservers = append(nameservers, string(ns[1]))
+		}
+	}
+	return nameservers
+}
+
+// GetNameserversAsCIDR returns nameservers (if any) listed in
+// /etc/resolv.conf as CIDR blocks (e.g., "1.2.3.4/32")
+// This function's output is intended for net.ParseCIDR
+func GetNameserversAsCIDR(resolvConf []byte) []string {
+	nameservers := []string{}
+	for _, nameserver := range GetNameservers(resolvConf, types.IP) {
+		var address string
+		// If IPv6, strip zone if present
+		if strings.Contains(nameserver, ":") {
+			address = strings.Split(nameserver, "%")[0] + "/128"
+		} else {
+			address = nameserver + "/32"
+		}
+		nameservers = append(nameservers, address)
+	}
+	return nameservers
+}
+
+// GetSearchDomains returns search domains (if any) listed in /etc/resolv.conf
+// If more than one search line is encountered, only the contents of the last
+// one is returned.
+func GetSearchDomains(resolvConf []byte) []string {
+	domains := []string{}
+	for _, line := range getLines(resolvConf, []byte("#")) {
+		match := searchRegexp.FindSubmatch(line)
+		if match == nil {
+			continue
+		}
+		domains = strings.Fields(string(match[1]))
+	}
+	return domains
+}
+
+// GetOptions returns options (if any) listed in /etc/resolv.conf
+// If more than one options line is encountered, only the contents of the last
+// one is returned.
+func GetOptions(resolvConf []byte) []string {
+	options := []string{}
+	for _, line := range getLines(resolvConf, []byte("#")) {
+		match := optionsRegexp.FindSubmatch(line)
+		if match == nil {
+			continue
+		}
+		options = strings.Fields(string(match[1]))
+	}
+	return options
+}
+
+// Build writes a configuration file to path containing a "nameserver" entry
+// for every element in dns, a "search" entry for every element in
+// dnsSearch, and an "options" entry for every element in dnsOptions.
+func Build(path string, dns, dnsSearch, dnsOptions []string) (*File, error) {
+	content := bytes.NewBuffer(nil)
+	if len(dnsSearch) > 0 {
+		if searchString := strings.Join(dnsSearch, " "); strings.Trim(searchString, " ") != "." {
+			if _, err := content.WriteString("search " + searchString + "\n"); err != nil {
+				return nil, err
+			}
+		}
+	}
+	for _, dns := range dns {
+		if _, err := content.WriteString("nameserver " + dns + "\n"); err != nil {
+			return nil, err
+		}
+	}
+	if len(dnsOptions) > 0 {
+		if optsString := strings.Join(dnsOptions, " "); strings.Trim(optsString, " ") != "" {
+			if _, err := content.WriteString("options " + optsString + "\n"); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	hash, err := ioutils.HashData(bytes.NewReader(content.Bytes()))
+	if err != nil {
+		return nil, err
+	}
+
+	return &File{Content: content.Bytes(), Hash: hash}, ioutil.WriteFile(path, content.Bytes(), 0644)
+}
diff --git a/vendor/github.com/docker/libnetwork/types/types.go b/vendor/github.com/docker/libnetwork/types/types.go
new file mode 100644
index 000000000..b102ba4c3
--- /dev/null
+++ b/vendor/github.com/docker/libnetwork/types/types.go
@@ -0,0 +1,653 @@
+// Package types contains types that are common across libnetwork project
+package types
+
+import (
+	"bytes"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+
+	"github.com/ishidawataru/sctp"
+)
+
+// constants for the IP address type
+const (
+	IP = iota // IPv4 and IPv6
+	IPv4
+	IPv6
+)
+
+// EncryptionKey is the libnetwork representation of the key distributed by the lead
+// manager.
+type EncryptionKey struct {
+	Subsystem   string
+	Algorithm   int32
+	Key         []byte
+	LamportTime uint64
+}
+
+// UUID represents a globally unique ID of various resources like network and endpoint
+type UUID string
+
+// QosPolicy represents a quality of service policy on an endpoint
+type QosPolicy struct {
+	MaxEgressBandwidth uint64
+}
+
+// TransportPort represents a local Layer 4 endpoint
+type TransportPort struct {
+	Proto Protocol
+	Port  uint16
+}
+
+// Equal checks if this instance of Transportport is equal to the passed one
+func (t *TransportPort) Equal(o *TransportPort) bool {
+	if t == o {
+		return true
+	}
+
+	if o == nil {
+		return false
+	}
+
+	if t.Proto != o.Proto || t.Port != o.Port {
+		return false
+	}
+
+	return true
+}
+
+// GetCopy returns a copy of this TransportPort structure instance
+func (t *TransportPort) GetCopy() TransportPort {
+	return TransportPort{Proto: t.Proto, Port: t.Port}
+}
+
+// String returns the TransportPort structure in string form
+func (t *TransportPort) String() string {
+	return fmt.Sprintf("%s/%d", t.Proto.String(), t.Port)
+}
+
+// FromString reads the TransportPort structure from string
+func (t *TransportPort) FromString(s string) error {
+	ps := strings.Split(s, "/")
+	if len(ps) == 2 {
+		t.Proto = ParseProtocol(ps[0])
+		if p, err := strconv.ParseUint(ps[1], 10, 16); err == nil {
+			t.Port = uint16(p)
+			return nil
+		}
+	}
+	return BadRequestErrorf("invalid format for transport port: %s", s)
+}
+
+// PortBinding represents a port binding between the container and the host
+type PortBinding struct {
+	Proto       Protocol
+	IP          net.IP
+	Port        uint16
+	HostIP      net.IP
+	HostPort    uint16
+	HostPortEnd uint16
+}
+
+// HostAddr returns the host side transport address
+func (p PortBinding) HostAddr() (net.Addr, error) {
+	switch p.Proto {
+	case UDP:
+		return &net.UDPAddr{IP: p.HostIP, Port: int(p.HostPort)}, nil
+	case TCP:
+		return &net.TCPAddr{IP: p.HostIP, Port: int(p.HostPort)}, nil
+	case SCTP:
+		return &sctp.SCTPAddr{IP: []net.IP{p.HostIP}, Port: int(p.HostPort)}, nil
+	default:
+		return nil, ErrInvalidProtocolBinding(p.Proto.String())
+	}
+}
+
+// ContainerAddr returns the container side transport address
+func (p PortBinding) ContainerAddr() (net.Addr, error) {
+	switch p.Proto {
+	case UDP:
+		return &net.UDPAddr{IP: p.IP, Port: int(p.Port)}, nil
+	case TCP:
+		return &net.TCPAddr{IP: p.IP, Port: int(p.Port)}, nil
+	case SCTP:
+		return &sctp.SCTPAddr{IP: []net.IP{p.IP}, Port: int(p.Port)}, nil
+	default:
+		return nil, ErrInvalidProtocolBinding(p.Proto.String())
+	}
+}
+
+// GetCopy returns a copy of this PortBinding structure instance
+func (p *PortBinding) GetCopy() PortBinding {
+	return PortBinding{
+		Proto:       p.Proto,
+		IP:          GetIPCopy(p.IP),
+		Port:        p.Port,
+		HostIP:      GetIPCopy(p.HostIP),
+		HostPort:    p.HostPort,
+		HostPortEnd: p.HostPortEnd,
+	}
+}
+
+// String returns the PortBinding structure in string form
+func (p *PortBinding) String() string {
+	ret := fmt.Sprintf("%s/", p.Proto)
+	if p.IP != nil {
+		ret += p.IP.String()
+	}
+	ret = fmt.Sprintf("%s:%d/", ret, p.Port)
+	if p.HostIP != nil {
+		ret += p.HostIP.String()
+	}
+	ret = fmt.Sprintf("%s:%d", ret, p.HostPort)
+	return ret
+}
+
+// FromString reads the PortBinding structure from string s.
+// String s is a triple of "protocol/containerIP:port/hostIP:port"
+// containerIP and hostIP can be in dotted decimal ("192.0.2.1") or IPv6 ("2001:db8::68") form.
+// Zoned addresses ("169.254.0.23%eth0" or "fe80::1ff:fe23:4567:890a%eth0") are not supported.
+// If string s is incorrectly formatted or the IP addresses or ports cannot be parsed, FromString
+// returns an error.
+func (p *PortBinding) FromString(s string) error {
+	ps := strings.Split(s, "/")
+	if len(ps) != 3 {
+		return BadRequestErrorf("invalid format for port binding: %s", s)
+	}
+
+	p.Proto = ParseProtocol(ps[0])
+
+	var err error
+	if p.IP, p.Port, err = parseIPPort(ps[1]); err != nil {
+		return BadRequestErrorf("failed to parse Container IP/Port in port binding: %s", err.Error())
+	}
+
+	if p.HostIP, p.HostPort, err = parseIPPort(ps[2]); err != nil {
+		return BadRequestErrorf("failed to parse Host IP/Port in port binding: %s", err.Error())
+	}
+
+	return nil
+}
+
+func parseIPPort(s string) (net.IP, uint16, error) {
+	hoststr, portstr, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	ip := net.ParseIP(hoststr)
+	if ip == nil {
+		return nil, 0, BadRequestErrorf("invalid ip: %s", hoststr)
+	}
+
+	port, err := strconv.ParseUint(portstr, 10, 16)
+	if err != nil {
+		return nil, 0, BadRequestErrorf("invalid port: %s", portstr)
+	}
+
+	return ip, uint16(port), nil
+}
+
+// Equal checks if this instance of PortBinding is equal to the passed one
+func (p *PortBinding) Equal(o *PortBinding) bool {
+	if p == o {
+		return true
+	}
+
+	if o == nil {
+		return false
+	}
+
+	if p.Proto != o.Proto || p.Port != o.Port ||
+		p.HostPort != o.HostPort || p.HostPortEnd != o.HostPortEnd {
+		return false
+	}
+
+	if p.IP != nil {
+		if !p.IP.Equal(o.IP) {
+			return false
+		}
+	} else {
+		if o.IP != nil {
+			return false
+		}
+	}
+
+	if p.HostIP != nil {
+		if !p.HostIP.Equal(o.HostIP) {
+			return false
+		}
+	} else {
+		if o.HostIP != nil {
+			return false
+		}
+	}
+
+	return true
+}
+
+// ErrInvalidProtocolBinding is returned when the port binding protocol is not valid.
+type ErrInvalidProtocolBinding string
+
+func (ipb ErrInvalidProtocolBinding) Error() string {
+	return fmt.Sprintf("invalid transport protocol: %s", string(ipb))
+}
+
+const (
+	// ICMP is for the ICMP ip protocol
+	ICMP = 1
+	// TCP is for the TCP ip protocol
+	TCP = 6
+	// UDP is for the UDP ip protocol
+	UDP = 17
+	// SCTP is for the SCTP ip protocol
+	SCTP = 132
+)
+
+// Protocol represents an IP protocol number
+type Protocol uint8
+
+func (p Protocol) String() string {
+	switch p {
+	case ICMP:
+		return "icmp"
+	case TCP:
+		return "tcp"
+	case UDP:
+		return "udp"
+	case SCTP:
+		return "sctp"
+	default:
+		return fmt.Sprintf("%d", p)
+	}
+}
+
+// ParseProtocol returns the respective Protocol type for the passed string
+func ParseProtocol(s string) Protocol {
+	switch strings.ToLower(s) {
+	case "icmp":
+		return ICMP
+	case "udp":
+		return UDP
+	case "tcp":
+		return TCP
+	case "sctp":
+		return SCTP
+	default:
+		return 0
+	}
+}
+
+// GetMacCopy returns a copy of the passed MAC address
+func GetMacCopy(from net.HardwareAddr) net.HardwareAddr {
+	if from == nil {
+		return nil
+	}
+	to := make(net.HardwareAddr, len(from))
+	copy(to, from)
+	return to
+}
+
+// GetIPCopy returns a copy of the passed IP address
+func GetIPCopy(from net.IP) net.IP {
+	if from == nil {
+		return nil
+	}
+	to := make(net.IP, len(from))
+	copy(to, from)
+	return to
+}
+
+// GetIPNetCopy returns a copy of the passed IP Network
+func GetIPNetCopy(from *net.IPNet) *net.IPNet {
+	if from == nil {
+		return nil
+	}
+	bm := make(net.IPMask, len(from.Mask))
+	copy(bm, from.Mask)
+	return &net.IPNet{IP: GetIPCopy(from.IP), Mask: bm}
+}
+
+// GetIPNetCanonical returns the canonical form for the passed network
+func GetIPNetCanonical(nw *net.IPNet) *net.IPNet {
+	if nw == nil {
+		return nil
+	}
+	c := GetIPNetCopy(nw)
+	c.IP = c.IP.Mask(nw.Mask)
+	return c
+}
+
+// CompareIPNet returns equal if the two IP Networks are equal
+func CompareIPNet(a, b *net.IPNet) bool {
+	if a == b {
+		return true
+	}
+	if a == nil || b == nil {
+		return false
+	}
+	return a.IP.Equal(b.IP) && bytes.Equal(a.Mask, b.Mask)
+}
+
+// GetMinimalIP returns the address in its shortest form
+// If ip contains an IPv4-mapped IPv6 address, the 4-octet form of the IPv4 address will be returned.
+// Otherwise ip is returned unchanged.
+func GetMinimalIP(ip net.IP) net.IP {
+	if ip != nil && ip.To4() != nil {
+		return ip.To4()
+	}
+	return ip
+}
+
+// GetMinimalIPNet returns a copy of the passed IP Network with congruent ip and mask notation
+func GetMinimalIPNet(nw *net.IPNet) *net.IPNet {
+	if nw == nil {
+		return nil
+	}
+	if len(nw.IP) == 16 && nw.IP.To4() != nil {
+		m := nw.Mask
+		if len(m) == 16 {
+			m = m[12:16]
+		}
+		return &net.IPNet{IP: nw.IP.To4(), Mask: m}
+	}
+	return nw
+}
+
+// IsIPNetValid returns true if the ipnet is a valid network/mask
+// combination. Otherwise returns false.
+func IsIPNetValid(nw *net.IPNet) bool {
+	return nw.String() != "0.0.0.0/0"
+}
+
+var v4inV6MaskPrefix = []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
+
+// compareIPMask checks if the passed ip and mask are semantically compatible.
+// It returns the byte indexes for the address and mask so that caller can
+// do bitwise operations without modifying address representation.
+func compareIPMask(ip net.IP, mask net.IPMask) (is int, ms int, err error) {
+	// Find the effective starting of address and mask
+	if len(ip) == net.IPv6len && ip.To4() != nil {
+		is = 12
+	}
+	if len(ip[is:]) == net.IPv4len && len(mask) == net.IPv6len && bytes.Equal(mask[:12], v4inV6MaskPrefix) {
+		ms = 12
+	}
+	// Check if address and mask are semantically compatible
+	if len(ip[is:]) != len(mask[ms:]) {
+		err = fmt.Errorf("ip and mask are not compatible: (%#v, %#v)", ip, mask)
+	}
+	return
+}
+
+// GetHostPartIP returns the host portion of the ip address identified by the mask.
+// IP address representation is not modified. If address and mask are not compatible
+// an error is returned.
+func GetHostPartIP(ip net.IP, mask net.IPMask) (net.IP, error) {
+	// Find the effective starting of address and mask
+	is, ms, err := compareIPMask(ip, mask)
+	if err != nil {
+		return nil, fmt.Errorf("cannot compute host portion ip address because %s", err)
+	}
+
+	// Compute host portion
+	out := GetIPCopy(ip)
+	for i := 0; i < len(mask[ms:]); i++ {
+		out[is+i] &= ^mask[ms+i]
+	}
+
+	return out, nil
+}
+
+// GetBroadcastIP returns the broadcast ip address for the passed network (ip and mask).
+// IP address representation is not modified. If address and mask are not compatible
+// an error is returned.
+func GetBroadcastIP(ip net.IP, mask net.IPMask) (net.IP, error) {
+	// Find the effective starting of address and mask
+	is, ms, err := compareIPMask(ip, mask)
+	if err != nil {
+		return nil, fmt.Errorf("cannot compute broadcast ip address because %s", err)
+	}
+
+	// Compute broadcast address
+	out := GetIPCopy(ip)
+	for i := 0; i < len(mask[ms:]); i++ {
+		out[is+i] |= ^mask[ms+i]
+	}
+
+	return out, nil
+}
+
+// ParseCIDR returns the *net.IPNet represented by the passed CIDR notation
+func ParseCIDR(cidr string) (n *net.IPNet, e error) {
+	var i net.IP
+	if i, n, e = net.ParseCIDR(cidr); e == nil {
+		n.IP = i
+	}
+	return
+}
+
+const (
+	// NEXTHOP indicates a StaticRoute with an IP next hop.
+	NEXTHOP = iota
+
+	// CONNECTED indicates a StaticRoute with an interface for directly connected peers.
+	CONNECTED
+)
+
+// StaticRoute is a statically-provisioned IP route.
+type StaticRoute struct {
+	Destination *net.IPNet
+
+	RouteType int // NEXT_HOP or CONNECTED
+
+	// NextHop will be resolved by the kernel (i.e. as a loose hop).
+	NextHop net.IP
+}
+
+// GetCopy returns a copy of this StaticRoute structure
+func (r *StaticRoute) GetCopy() *StaticRoute {
+	d := GetIPNetCopy(r.Destination)
+	nh := GetIPCopy(r.NextHop)
+	return &StaticRoute{Destination: d,
+		RouteType: r.RouteType,
+		NextHop:   nh,
+	}
+}
+
+// InterfaceStatistics represents the interface's statistics
+type InterfaceStatistics struct {
+	RxBytes   uint64
+	RxPackets uint64
+	RxErrors  uint64
+	RxDropped uint64
+	TxBytes   uint64
+	TxPackets uint64
+	TxErrors  uint64
+	TxDropped uint64
+}
+
+func (is *InterfaceStatistics) String() string {
+	return fmt.Sprintf("\nRxBytes: %d, RxPackets: %d, RxErrors: %d, RxDropped: %d, TxBytes: %d, TxPackets: %d, TxErrors: %d, TxDropped: %d",
+		is.RxBytes, is.RxPackets, is.RxErrors, is.RxDropped, is.TxBytes, is.TxPackets, is.TxErrors, is.TxDropped)
+}
+
+/******************************
+ * Well-known Error Interfaces
+ ******************************/
+
+// MaskableError is an interface for errors which can be ignored by caller
+type MaskableError interface {
+	// Maskable makes implementer into MaskableError type
+	Maskable()
+}
+
+// RetryError is an interface for errors which might get resolved through retry
+type RetryError interface {
+	// Retry makes implementer into RetryError type
+	Retry()
+}
+
+// BadRequestError is an interface for errors originated by a bad request
+type BadRequestError interface {
+	// BadRequest makes implementer into BadRequestError type
+	BadRequest()
+}
+
+// NotFoundError is an interface for errors raised because a needed resource is not available
+type NotFoundError interface {
+	// NotFound makes implementer into NotFoundError type
+	NotFound()
+}
+
+// ForbiddenError is an interface for errors which denote a valid request that cannot be honored
+type ForbiddenError interface {
+	// Forbidden makes implementer into ForbiddenError type
+	Forbidden()
+}
+
+// NoServiceError is an interface for errors returned when the required service is not available
+type NoServiceError interface {
+	// NoService makes implementer into NoServiceError type
+	NoService()
+}
+
+// TimeoutError is an interface for errors raised because of timeout
+type TimeoutError interface {
+	// Timeout makes implementer into TimeoutError type
+	Timeout()
+}
+
+// NotImplementedError is an interface for errors raised because of requested functionality is not yet implemented
+type NotImplementedError interface {
+	// NotImplemented makes implementer into NotImplementedError type
+	NotImplemented()
+}
+
+// InternalError is an interface for errors raised because of an internal error
+type InternalError interface {
+	// Internal makes implementer into InternalError type
+	Internal()
+}
+
+/******************************
+ * Well-known Error Formatters
+ ******************************/
+
+// BadRequestErrorf creates an instance of BadRequestError
+func BadRequestErrorf(format string, params ...interface{}) error {
+	return badRequest(fmt.Sprintf(format, params...))
+}
+
+// NotFoundErrorf creates an instance of NotFoundError
+func NotFoundErrorf(format string, params ...interface{}) error {
+	return notFound(fmt.Sprintf(format, params...))
+}
+
+// ForbiddenErrorf creates an instance of ForbiddenError
+func ForbiddenErrorf(format string, params ...interface{}) error {
+	return forbidden(fmt.Sprintf(format, params...))
+}
+
+// NoServiceErrorf creates an instance of NoServiceError
+func NoServiceErrorf(format string, params ...interface{}) error {
+	return noService(fmt.Sprintf(format, params...))
+}
+
+// NotImplementedErrorf creates an instance of NotImplementedError
+func NotImplementedErrorf(format string, params ...interface{}) error {
+	return notImpl(fmt.Sprintf(format, params...))
+}
+
+// TimeoutErrorf creates an instance of TimeoutError
+func TimeoutErrorf(format string, params ...interface{}) error {
+	return timeout(fmt.Sprintf(format, params...))
+}
+
+// InternalErrorf creates an instance of InternalError
+func InternalErrorf(format string, params ...interface{}) error {
+	return internal(fmt.Sprintf(format, params...))
+}
+
+// InternalMaskableErrorf creates an instance of InternalError and MaskableError
+func InternalMaskableErrorf(format string, params ...interface{}) error {
+	return maskInternal(fmt.Sprintf(format, params...))
+}
+
+// RetryErrorf creates an instance of RetryError
+func RetryErrorf(format string, params ...interface{}) error {
+	return retry(fmt.Sprintf(format, params...))
+}
+
+/***********************
+ * Internal Error Types
+ ***********************/
+type badRequest string
+
+func (br badRequest) Error() string {
+	return string(br)
+}
+func (br badRequest) BadRequest() {}
+
+type maskBadRequest string
+
+type notFound string
+
+func (nf notFound) Error() string {
+	return string(nf)
+}
+func (nf notFound) NotFound() {}
+
+type forbidden string
+
+func (frb forbidden) Error() string {
+	return string(frb)
+}
+func (frb forbidden) Forbidden() {}
+
+type noService string
+
+func (ns noService) Error() string {
+	return string(ns)
+}
+func (ns noService) NoService() {}
+
+type maskNoService string
+
+type timeout string
+
+func (to timeout) Error() string {
+	return string(to)
+}
+func (to timeout) Timeout() {}
+
+type notImpl string
+
+func (ni notImpl) Error() string {
+	return string(ni)
+}
+func (ni notImpl) NotImplemented() {}
+
+type internal string
+
+func (nt internal) Error() string {
+	return string(nt)
+}
+func (nt internal) Internal() {}
+
+type maskInternal string
+
+func (mnt maskInternal) Error() string {
+	return string(mnt)
+}
+func (mnt maskInternal) Internal() {}
+func (mnt maskInternal) Maskable() {}
+
+type retry string
+
+func (r retry) Error() string {
+	return string(r)
+}
+func (r retry) Retry() {}
diff --git a/vendor/github.com/ishidawataru/sctp/LICENSE b/vendor/github.com/ishidawataru/sctp/LICENSE
new file mode 100644
index 000000000..8dada3eda
--- /dev/null
+++ b/vendor/github.com/ishidawataru/sctp/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
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+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
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+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
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+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
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+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright {yyyy} {name of copyright owner}
+
+   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.
diff --git a/vendor/github.com/ishidawataru/sctp/README.md b/vendor/github.com/ishidawataru/sctp/README.md
new file mode 100644
index 000000000..574ececa8
--- /dev/null
+++ b/vendor/github.com/ishidawataru/sctp/README.md
@@ -0,0 +1,18 @@
+Stream Control Transmission Protocol (SCTP)
+----
+
+[![Build Status](https://travis-ci.org/ishidawataru/sctp.svg?branch=master)](https://travis-ci.org/ishidawataru/sctp/builds)
+
+Examples
+----
+
+See `example/sctp.go`
+
+```go
+$ cd example
+$ go build
+$ # run example SCTP server
+$ ./example -server -port 1000 -ip 10.10.0.1,10.20.0.1
+$ # run example SCTP client
+$ ./example -port 1000 -ip 10.10.0.1,10.20.0.1
+```
diff --git a/vendor/github.com/ishidawataru/sctp/sctp.go b/vendor/github.com/ishidawataru/sctp/sctp.go
new file mode 100644
index 000000000..cac1a889c
--- /dev/null
+++ b/vendor/github.com/ishidawataru/sctp/sctp.go
@@ -0,0 +1,656 @@
+package sctp
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+const (
+	SOL_SCTP = 132
+
+	SCTP_BINDX_ADD_ADDR = 0x01
+	SCTP_BINDX_REM_ADDR = 0x02
+
+	MSG_NOTIFICATION = 0x8000
+)
+
+const (
+	SCTP_RTOINFO = iota
+	SCTP_ASSOCINFO
+	SCTP_INITMSG
+	SCTP_NODELAY
+	SCTP_AUTOCLOSE
+	SCTP_SET_PEER_PRIMARY_ADDR
+	SCTP_PRIMARY_ADDR
+	SCTP_ADAPTATION_LAYER
+	SCTP_DISABLE_FRAGMENTS
+	SCTP_PEER_ADDR_PARAMS
+	SCTP_DEFAULT_SENT_PARAM
+	SCTP_EVENTS
+	SCTP_I_WANT_MAPPED_V4_ADDR
+	SCTP_MAXSEG
+	SCTP_STATUS
+	SCTP_GET_PEER_ADDR_INFO
+	SCTP_DELAYED_ACK_TIME
+	SCTP_DELAYED_ACK  = SCTP_DELAYED_ACK_TIME
+	SCTP_DELAYED_SACK = SCTP_DELAYED_ACK_TIME
+
+	SCTP_SOCKOPT_BINDX_ADD = 100
+	SCTP_SOCKOPT_BINDX_REM = 101
+	SCTP_SOCKOPT_PEELOFF   = 102
+	SCTP_GET_PEER_ADDRS    = 108
+	SCTP_GET_LOCAL_ADDRS   = 109
+	SCTP_SOCKOPT_CONNECTX  = 110
+	SCTP_SOCKOPT_CONNECTX3 = 111
+)
+
+const (
+	SCTP_EVENT_DATA_IO = 1 << iota
+	SCTP_EVENT_ASSOCIATION
+	SCTP_EVENT_ADDRESS
+	SCTP_EVENT_SEND_FAILURE
+	SCTP_EVENT_PEER_ERROR
+	SCTP_EVENT_SHUTDOWN
+	SCTP_EVENT_PARTIAL_DELIVERY
+	SCTP_EVENT_ADAPTATION_LAYER
+	SCTP_EVENT_AUTHENTICATION
+	SCTP_EVENT_SENDER_DRY
+
+	SCTP_EVENT_ALL = SCTP_EVENT_DATA_IO | SCTP_EVENT_ASSOCIATION | SCTP_EVENT_ADDRESS | SCTP_EVENT_SEND_FAILURE | SCTP_EVENT_PEER_ERROR | SCTP_EVENT_SHUTDOWN | SCTP_EVENT_PARTIAL_DELIVERY | SCTP_EVENT_ADAPTATION_LAYER | SCTP_EVENT_AUTHENTICATION | SCTP_EVENT_SENDER_DRY
+)
+
+type SCTPNotificationType int
+
+const (
+	SCTP_SN_TYPE_BASE = SCTPNotificationType(iota + (1 << 15))
+	SCTP_ASSOC_CHANGE
+	SCTP_PEER_ADDR_CHANGE
+	SCTP_SEND_FAILED
+	SCTP_REMOTE_ERROR
+	SCTP_SHUTDOWN_EVENT
+	SCTP_PARTIAL_DELIVERY_EVENT
+	SCTP_ADAPTATION_INDICATION
+	SCTP_AUTHENTICATION_INDICATION
+	SCTP_SENDER_DRY_EVENT
+)
+
+type NotificationHandler func([]byte) error
+
+type EventSubscribe struct {
+	DataIO          uint8
+	Association     uint8
+	Address         uint8
+	SendFailure     uint8
+	PeerError       uint8
+	Shutdown        uint8
+	PartialDelivery uint8
+	AdaptationLayer uint8
+	Authentication  uint8
+	SenderDry       uint8
+}
+
+const (
+	SCTP_CMSG_INIT = iota
+	SCTP_CMSG_SNDRCV
+	SCTP_CMSG_SNDINFO
+	SCTP_CMSG_RCVINFO
+	SCTP_CMSG_NXTINFO
+)
+
+const (
+	SCTP_UNORDERED = 1 << iota
+	SCTP_ADDR_OVER
+	SCTP_ABORT
+	SCTP_SACK_IMMEDIATELY
+	SCTP_EOF
+)
+
+const (
+	SCTP_MAX_STREAM = 0xffff
+)
+
+type InitMsg struct {
+	NumOstreams    uint16
+	MaxInstreams   uint16
+	MaxAttempts    uint16
+	MaxInitTimeout uint16
+}
+
+type SndRcvInfo struct {
+	Stream  uint16
+	SSN     uint16
+	Flags   uint16
+	_       uint16
+	PPID    uint32
+	Context uint32
+	TTL     uint32
+	TSN     uint32
+	CumTSN  uint32
+	AssocID int32
+}
+
+type SndInfo struct {
+	SID     uint16
+	Flags   uint16
+	PPID    uint32
+	Context uint32
+	AssocID int32
+}
+
+type GetAddrsOld struct {
+	AssocID int32
+	AddrNum int32
+	Addrs   uintptr
+}
+
+type NotificationHeader struct {
+	Type   uint16
+	Flags  uint16
+	Length uint32
+}
+
+type SCTPState uint16
+
+const (
+	SCTP_COMM_UP = SCTPState(iota)
+	SCTP_COMM_LOST
+	SCTP_RESTART
+	SCTP_SHUTDOWN_COMP
+	SCTP_CANT_STR_ASSOC
+)
+
+var nativeEndian binary.ByteOrder
+var sndRcvInfoSize uintptr
+
+func init() {
+	i := uint16(1)
+	if *(*byte)(unsafe.Pointer(&i)) == 0 {
+		nativeEndian = binary.BigEndian
+	} else {
+		nativeEndian = binary.LittleEndian
+	}
+	info := SndRcvInfo{}
+	sndRcvInfoSize = unsafe.Sizeof(info)
+}
+
+func toBuf(v interface{}) []byte {
+	var buf bytes.Buffer
+	binary.Write(&buf, nativeEndian, v)
+	return buf.Bytes()
+}
+
+func htons(h uint16) uint16 {
+	if nativeEndian == binary.LittleEndian {
+		return (h << 8 & 0xff00) | (h >> 8 & 0xff)
+	}
+	return h
+}
+
+var ntohs = htons
+
+func setNumOstreams(fd, num int) error {
+	param := InitMsg{
+		NumOstreams: uint16(num),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := setsockopt(fd, SCTP_INITMSG, uintptr(unsafe.Pointer(&param)), uintptr(optlen))
+	return err
+}
+
+type SCTPAddr struct {
+	IP   []net.IP
+	Port int
+}
+
+func (a *SCTPAddr) ToRawSockAddrBuf() []byte {
+	buf := []byte{}
+	p := htons(uint16(a.Port))
+	for _, ip := range a.IP {
+		if ip.To4() != nil {
+			s := syscall.RawSockaddrInet4{
+				Family: syscall.AF_INET,
+				Port:   p,
+			}
+			copy(s.Addr[:], ip.To4())
+			buf = append(buf, toBuf(s)...)
+		} else {
+			s := syscall.RawSockaddrInet6{
+				Family: syscall.AF_INET6,
+				Port:   p,
+			}
+			copy(s.Addr[:], ip)
+			buf = append(buf, toBuf(s)...)
+		}
+	}
+	return buf
+}
+
+func (a *SCTPAddr) String() string {
+	var b bytes.Buffer
+
+	for n, i := range a.IP {
+		if a.IP[n].To4() != nil {
+			b.WriteString(i.String())
+		} else if a.IP[n].To16() != nil {
+			b.WriteRune('[')
+			b.WriteString(i.String())
+			b.WriteRune(']')
+		}
+		if n < len(a.IP)-1 {
+			b.WriteRune('/')
+		}
+	}
+	b.WriteRune(':')
+	b.WriteString(strconv.Itoa(a.Port))
+	return b.String()
+}
+
+func (a *SCTPAddr) Network() string { return "sctp" }
+
+func ResolveSCTPAddr(network, addrs string) (*SCTPAddr, error) {
+	tcpnet := ""
+	switch network {
+	case "", "sctp":
+	case "sctp4":
+		tcpnet = "tcp4"
+	case "sctp6":
+		tcpnet = "tcp6"
+	default:
+		return nil, fmt.Errorf("invalid net: %s", network)
+	}
+	elems := strings.Split(addrs, "/")
+	if len(elems) == 0 {
+		return nil, fmt.Errorf("invalid input: %s", addrs)
+	}
+	ipaddrs := make([]net.IP, 0, len(elems))
+	for _, e := range elems[:len(elems)-1] {
+		tcpa, err := net.ResolveTCPAddr(tcpnet, e+":")
+		if err != nil {
+			return nil, err
+		}
+		ipaddrs = append(ipaddrs, tcpa.IP)
+	}
+	tcpa, err := net.ResolveTCPAddr(tcpnet, elems[len(elems)-1])
+	if err != nil {
+		return nil, err
+	}
+	if tcpa.IP != nil {
+		ipaddrs = append(ipaddrs, tcpa.IP)
+	} else {
+		ipaddrs = nil
+	}
+	return &SCTPAddr{
+		IP:   ipaddrs,
+		Port: tcpa.Port,
+	}, nil
+}
+
+func SCTPConnect(fd int, addr *SCTPAddr) (int, error) {
+	buf := addr.ToRawSockAddrBuf()
+	param := GetAddrsOld{
+		AddrNum: int32(len(buf)),
+		Addrs:   uintptr(uintptr(unsafe.Pointer(&buf[0]))),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := getsockopt(fd, SCTP_SOCKOPT_CONNECTX3, uintptr(unsafe.Pointer(&param)), uintptr(unsafe.Pointer(&optlen)))
+	if err == nil {
+		return int(param.AssocID), nil
+	} else if err != syscall.ENOPROTOOPT {
+		return 0, err
+	}
+	r0, _, err := setsockopt(fd, SCTP_SOCKOPT_CONNECTX, uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)))
+	return int(r0), err
+}
+
+func SCTPBind(fd int, addr *SCTPAddr, flags int) error {
+	var option uintptr
+	switch flags {
+	case SCTP_BINDX_ADD_ADDR:
+		option = SCTP_SOCKOPT_BINDX_ADD
+	case SCTP_BINDX_REM_ADDR:
+		option = SCTP_SOCKOPT_BINDX_REM
+	default:
+		return syscall.EINVAL
+	}
+
+	buf := addr.ToRawSockAddrBuf()
+	_, _, err := setsockopt(fd, option, uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)))
+	return err
+}
+
+type SCTPConn struct {
+	_fd                 int32
+	notificationHandler NotificationHandler
+}
+
+func (c *SCTPConn) fd() int {
+	return int(atomic.LoadInt32(&c._fd))
+}
+
+func NewSCTPConn(fd int, handler NotificationHandler) *SCTPConn {
+	conn := &SCTPConn{
+		_fd:                 int32(fd),
+		notificationHandler: handler,
+	}
+	return conn
+}
+
+func (c *SCTPConn) Write(b []byte) (int, error) {
+	return c.SCTPWrite(b, nil)
+}
+
+func (c *SCTPConn) Read(b []byte) (int, error) {
+	n, _, err := c.SCTPRead(b)
+	if n < 0 {
+		n = 0
+	}
+	return n, err
+}
+
+func (c *SCTPConn) SetInitMsg(numOstreams, maxInstreams, maxAttempts, maxInitTimeout int) error {
+	param := InitMsg{
+		NumOstreams:    uint16(numOstreams),
+		MaxInstreams:   uint16(maxInstreams),
+		MaxAttempts:    uint16(maxAttempts),
+		MaxInitTimeout: uint16(maxInitTimeout),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := setsockopt(c.fd(), SCTP_INITMSG, uintptr(unsafe.Pointer(&param)), uintptr(optlen))
+	return err
+}
+
+func (c *SCTPConn) SubscribeEvents(flags int) error {
+	var d, a, ad, sf, p, sh, pa, ada, au, se uint8
+	if flags&SCTP_EVENT_DATA_IO > 0 {
+		d = 1
+	}
+	if flags&SCTP_EVENT_ASSOCIATION > 0 {
+		a = 1
+	}
+	if flags&SCTP_EVENT_ADDRESS > 0 {
+		ad = 1
+	}
+	if flags&SCTP_EVENT_SEND_FAILURE > 0 {
+		sf = 1
+	}
+	if flags&SCTP_EVENT_PEER_ERROR > 0 {
+		p = 1
+	}
+	if flags&SCTP_EVENT_SHUTDOWN > 0 {
+		sh = 1
+	}
+	if flags&SCTP_EVENT_PARTIAL_DELIVERY > 0 {
+		pa = 1
+	}
+	if flags&SCTP_EVENT_ADAPTATION_LAYER > 0 {
+		ada = 1
+	}
+	if flags&SCTP_EVENT_AUTHENTICATION > 0 {
+		au = 1
+	}
+	if flags&SCTP_EVENT_SENDER_DRY > 0 {
+		se = 1
+	}
+	param := EventSubscribe{
+		DataIO:          d,
+		Association:     a,
+		Address:         ad,
+		SendFailure:     sf,
+		PeerError:       p,
+		Shutdown:        sh,
+		PartialDelivery: pa,
+		AdaptationLayer: ada,
+		Authentication:  au,
+		SenderDry:       se,
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := setsockopt(c.fd(), SCTP_EVENTS, uintptr(unsafe.Pointer(&param)), uintptr(optlen))
+	return err
+}
+
+func (c *SCTPConn) SubscribedEvents() (int, error) {
+	param := EventSubscribe{}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := getsockopt(c.fd(), SCTP_EVENTS, uintptr(unsafe.Pointer(&param)), uintptr(unsafe.Pointer(&optlen)))
+	if err != nil {
+		return 0, err
+	}
+	var flags int
+	if param.DataIO > 0 {
+		flags |= SCTP_EVENT_DATA_IO
+	}
+	if param.Association > 0 {
+		flags |= SCTP_EVENT_ASSOCIATION
+	}
+	if param.Address > 0 {
+		flags |= SCTP_EVENT_ADDRESS
+	}
+	if param.SendFailure > 0 {
+		flags |= SCTP_EVENT_SEND_FAILURE
+	}
+	if param.PeerError > 0 {
+		flags |= SCTP_EVENT_PEER_ERROR
+	}
+	if param.Shutdown > 0 {
+		flags |= SCTP_EVENT_SHUTDOWN
+	}
+	if param.PartialDelivery > 0 {
+		flags |= SCTP_EVENT_PARTIAL_DELIVERY
+	}
+	if param.AdaptationLayer > 0 {
+		flags |= SCTP_EVENT_ADAPTATION_LAYER
+	}
+	if param.Authentication > 0 {
+		flags |= SCTP_EVENT_AUTHENTICATION
+	}
+	if param.SenderDry > 0 {
+		flags |= SCTP_EVENT_SENDER_DRY
+	}
+	return flags, nil
+}
+
+func (c *SCTPConn) SetDefaultSentParam(info *SndRcvInfo) error {
+	optlen := unsafe.Sizeof(*info)
+	_, _, err := setsockopt(c.fd(), SCTP_DEFAULT_SENT_PARAM, uintptr(unsafe.Pointer(info)), uintptr(optlen))
+	return err
+}
+
+func (c *SCTPConn) GetDefaultSentParam() (*SndRcvInfo, error) {
+	info := &SndRcvInfo{}
+	optlen := unsafe.Sizeof(*info)
+	_, _, err := getsockopt(c.fd(), SCTP_DEFAULT_SENT_PARAM, uintptr(unsafe.Pointer(info)), uintptr(unsafe.Pointer(&optlen)))
+	return info, err
+}
+
+func resolveFromRawAddr(ptr unsafe.Pointer, n int) (*SCTPAddr, error) {
+	addr := &SCTPAddr{
+		IP: make([]net.IP, n),
+	}
+
+	switch family := (*(*syscall.RawSockaddrAny)(ptr)).Addr.Family; family {
+	case syscall.AF_INET:
+		addr.Port = int(ntohs(uint16((*(*syscall.RawSockaddrInet4)(ptr)).Port)))
+		tmp := syscall.RawSockaddrInet4{}
+		size := unsafe.Sizeof(tmp)
+		for i := 0; i < n; i++ {
+			a := *(*syscall.RawSockaddrInet4)(unsafe.Pointer(
+				uintptr(ptr) + size*uintptr(i)))
+			addr.IP[i] = a.Addr[:]
+		}
+	case syscall.AF_INET6:
+		addr.Port = int(ntohs(uint16((*(*syscall.RawSockaddrInet4)(ptr)).Port)))
+		tmp := syscall.RawSockaddrInet6{}
+		size := unsafe.Sizeof(tmp)
+		for i := 0; i < n; i++ {
+			a := *(*syscall.RawSockaddrInet6)(unsafe.Pointer(
+				uintptr(ptr) + size*uintptr(i)))
+			addr.IP[i] = a.Addr[:]
+		}
+	default:
+		return nil, fmt.Errorf("unknown address family: %d", family)
+	}
+	return addr, nil
+}
+
+func sctpGetAddrs(fd, id, optname int) (*SCTPAddr, error) {
+
+	type getaddrs struct {
+		assocId int32
+		addrNum uint32
+		addrs   [4096]byte
+	}
+	param := getaddrs{
+		assocId: int32(id),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := getsockopt(fd, uintptr(optname), uintptr(unsafe.Pointer(&param)), uintptr(unsafe.Pointer(&optlen)))
+	if err != nil {
+		return nil, err
+	}
+	return resolveFromRawAddr(unsafe.Pointer(&param.addrs), int(param.addrNum))
+}
+
+func (c *SCTPConn) SCTPGetPrimaryPeerAddr() (*SCTPAddr, error) {
+
+	type sctpGetSetPrim struct {
+		assocId int32
+		addrs   [128]byte
+	}
+	param := sctpGetSetPrim{
+		assocId: int32(0),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := getsockopt(c.fd(), SCTP_PRIMARY_ADDR, uintptr(unsafe.Pointer(&param)), uintptr(unsafe.Pointer(&optlen)))
+	if err != nil {
+		return nil, err
+	}
+	return resolveFromRawAddr(unsafe.Pointer(&param.addrs), 1)
+}
+
+func (c *SCTPConn) SCTPLocalAddr(id int) (*SCTPAddr, error) {
+	return sctpGetAddrs(c.fd(), id, SCTP_GET_LOCAL_ADDRS)
+}
+
+func (c *SCTPConn) SCTPRemoteAddr(id int) (*SCTPAddr, error) {
+	return sctpGetAddrs(c.fd(), id, SCTP_GET_PEER_ADDRS)
+}
+
+func (c *SCTPConn) LocalAddr() net.Addr {
+	addr, err := sctpGetAddrs(c.fd(), 0, SCTP_GET_LOCAL_ADDRS)
+	if err != nil {
+		return nil
+	}
+	return addr
+}
+
+func (c *SCTPConn) RemoteAddr() net.Addr {
+	addr, err := sctpGetAddrs(c.fd(), 0, SCTP_GET_PEER_ADDRS)
+	if err != nil {
+		return nil
+	}
+	return addr
+}
+
+func (c *SCTPConn) PeelOff(id int) (*SCTPConn, error) {
+	type peeloffArg struct {
+		assocId int32
+		sd      int
+	}
+	param := peeloffArg{
+		assocId: int32(id),
+	}
+	optlen := unsafe.Sizeof(param)
+	_, _, err := getsockopt(c.fd(), SCTP_SOCKOPT_PEELOFF, uintptr(unsafe.Pointer(&param)), uintptr(unsafe.Pointer(&optlen)))
+	if err != nil {
+		return nil, err
+	}
+	return &SCTPConn{_fd: int32(param.sd)}, nil
+}
+
+func (c *SCTPConn) SetDeadline(t time.Time) error {
+	return syscall.EOPNOTSUPP
+}
+
+func (c *SCTPConn) SetReadDeadline(t time.Time) error {
+	return syscall.EOPNOTSUPP
+}
+
+func (c *SCTPConn) SetWriteDeadline(t time.Time) error {
+	return syscall.EOPNOTSUPP
+}
+
+type SCTPListener struct {
+	fd int
+	m  sync.Mutex
+}
+
+func (ln *SCTPListener) Addr() net.Addr {
+	laddr, err := sctpGetAddrs(ln.fd, 0, SCTP_GET_LOCAL_ADDRS)
+	if err != nil {
+		return nil
+	}
+	return laddr
+}
+
+type SCTPSndRcvInfoWrappedConn struct {
+	conn *SCTPConn
+}
+
+func NewSCTPSndRcvInfoWrappedConn(conn *SCTPConn) *SCTPSndRcvInfoWrappedConn {
+	conn.SubscribeEvents(SCTP_EVENT_DATA_IO)
+	return &SCTPSndRcvInfoWrappedConn{conn}
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) Write(b []byte) (int, error) {
+	if len(b) < int(sndRcvInfoSize) {
+		return 0, syscall.EINVAL
+	}
+	info := (*SndRcvInfo)(unsafe.Pointer(&b[0]))
+	n, err := c.conn.SCTPWrite(b[sndRcvInfoSize:], info)
+	return n + int(sndRcvInfoSize), err
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) Read(b []byte) (int, error) {
+	if len(b) < int(sndRcvInfoSize) {
+		return 0, syscall.EINVAL
+	}
+	n, info, err := c.conn.SCTPRead(b[sndRcvInfoSize:])
+	if err != nil {
+		return n, err
+	}
+	copy(b, toBuf(info))
+	return n + int(sndRcvInfoSize), err
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) Close() error {
+	return c.conn.Close()
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) LocalAddr() net.Addr {
+	return c.conn.LocalAddr()
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) RemoteAddr() net.Addr {
+	return c.conn.RemoteAddr()
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) SetDeadline(t time.Time) error {
+	return c.conn.SetDeadline(t)
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) SetReadDeadline(t time.Time) error {
+	return c.conn.SetReadDeadline(t)
+}
+
+func (c *SCTPSndRcvInfoWrappedConn) SetWriteDeadline(t time.Time) error {
+	return c.conn.SetWriteDeadline(t)
+}
diff --git a/vendor/github.com/ishidawataru/sctp/sctp_linux.go b/vendor/github.com/ishidawataru/sctp/sctp_linux.go
new file mode 100644
index 000000000..f93ab8622
--- /dev/null
+++ b/vendor/github.com/ishidawataru/sctp/sctp_linux.go
@@ -0,0 +1,227 @@
+// +build linux,!386
+
+package sctp
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"sync/atomic"
+	"syscall"
+	"unsafe"
+)
+
+func setsockopt(fd int, optname, optval, optlen uintptr) (uintptr, uintptr, error) {
+	// FIXME: syscall.SYS_SETSOCKOPT is undefined on 386
+	r0, r1, errno := syscall.Syscall6(syscall.SYS_SETSOCKOPT,
+		uintptr(fd),
+		SOL_SCTP,
+		optname,
+		optval,
+		optlen,
+		0)
+	if errno != 0 {
+		return r0, r1, errno
+	}
+	return r0, r1, nil
+}
+
+func getsockopt(fd int, optname, optval, optlen uintptr) (uintptr, uintptr, error) {
+	// FIXME: syscall.SYS_GETSOCKOPT is undefined on 386
+	r0, r1, errno := syscall.Syscall6(syscall.SYS_GETSOCKOPT,
+		uintptr(fd),
+		SOL_SCTP,
+		optname,
+		optval,
+		optlen,
+		0)
+	if errno != 0 {
+		return r0, r1, errno
+	}
+	return r0, r1, nil
+}
+
+func (c *SCTPConn) SCTPWrite(b []byte, info *SndRcvInfo) (int, error) {
+	var cbuf []byte
+	if info != nil {
+		cmsgBuf := toBuf(info)
+		hdr := &syscall.Cmsghdr{
+			Level: syscall.IPPROTO_SCTP,
+			Type:  SCTP_CMSG_SNDRCV,
+		}
+
+		// bitwidth of hdr.Len is platform-specific,
+		// so we use hdr.SetLen() rather than directly setting hdr.Len
+		hdr.SetLen(syscall.CmsgSpace(len(cmsgBuf)))
+		cbuf = append(toBuf(hdr), cmsgBuf...)
+	}
+	return syscall.SendmsgN(c.fd(), b, cbuf, nil, 0)
+}
+
+func parseSndRcvInfo(b []byte) (*SndRcvInfo, error) {
+	msgs, err := syscall.ParseSocketControlMessage(b)
+	if err != nil {
+		return nil, err
+	}
+	for _, m := range msgs {
+		if m.Header.Level == syscall.IPPROTO_SCTP {
+			switch m.Header.Type {
+			case SCTP_CMSG_SNDRCV:
+				return (*SndRcvInfo)(unsafe.Pointer(&m.Data[0])), nil
+			}
+		}
+	}
+	return nil, nil
+}
+
+func (c *SCTPConn) SCTPRead(b []byte) (int, *SndRcvInfo, error) {
+	oob := make([]byte, 254)
+	for {
+		n, oobn, recvflags, _, err := syscall.Recvmsg(c.fd(), b, oob, 0)
+		if err != nil {
+			return n, nil, err
+		}
+
+		if n == 0 && oobn == 0 {
+			return 0, nil, io.EOF
+		}
+
+		if recvflags&MSG_NOTIFICATION > 0 && c.notificationHandler != nil {
+			if err := c.notificationHandler(b[:n]); err != nil {
+				return 0, nil, err
+			}
+		} else {
+			var info *SndRcvInfo
+			if oobn > 0 {
+				info, err = parseSndRcvInfo(oob[:oobn])
+			}
+			return n, info, err
+		}
+	}
+}
+
+func (c *SCTPConn) Close() error {
+	if c != nil {
+		fd := atomic.SwapInt32(&c._fd, -1)
+		if fd > 0 {
+			info := &SndRcvInfo{
+				Flags: SCTP_EOF,
+			}
+			c.SCTPWrite(nil, info)
+			syscall.Shutdown(int(fd), syscall.SHUT_RDWR)
+			return syscall.Close(int(fd))
+		}
+	}
+	return syscall.EBADF
+}
+
+func ListenSCTP(net string, laddr *SCTPAddr) (*SCTPListener, error) {
+	af := syscall.AF_INET
+	switch net {
+	case "sctp":
+		hasv6 := func(addr *SCTPAddr) bool {
+			if addr == nil {
+				return false
+			}
+			for _, ip := range addr.IP {
+				if ip.To4() == nil {
+					return true
+				}
+			}
+			return false
+		}
+		if hasv6(laddr) {
+			af = syscall.AF_INET6
+		}
+	case "sctp4":
+	case "sctp6":
+		af = syscall.AF_INET6
+	default:
+		return nil, fmt.Errorf("invalid net: %s", net)
+	}
+
+	sock, err := syscall.Socket(
+		af,
+		syscall.SOCK_STREAM,
+		syscall.IPPROTO_SCTP,
+	)
+	if err != nil {
+		return nil, err
+	}
+	err = setNumOstreams(sock, SCTP_MAX_STREAM)
+	if err != nil {
+		return nil, err
+	}
+	if laddr != nil && len(laddr.IP) != 0 {
+		err := SCTPBind(sock, laddr, SCTP_BINDX_ADD_ADDR)
+		if err != nil {
+			return nil, err
+		}
+	}
+	err = syscall.Listen(sock, syscall.SOMAXCONN)
+	if err != nil {
+		return nil, err
+	}
+	return &SCTPListener{
+		fd: sock,
+	}, nil
+}
+
+func (ln *SCTPListener) Accept() (net.Conn, error) {
+	fd, _, err := syscall.Accept4(ln.fd, 0)
+	return NewSCTPConn(fd, nil), err
+}
+
+func (ln *SCTPListener) Close() error {
+	syscall.Shutdown(ln.fd, syscall.SHUT_RDWR)
+	return syscall.Close(ln.fd)
+}
+
+func DialSCTP(net string, laddr, raddr *SCTPAddr) (*SCTPConn, error) {
+	af := syscall.AF_INET
+	switch net {
+	case "sctp":
+		hasv6 := func(addr *SCTPAddr) bool {
+			if addr == nil {
+				return false
+			}
+			for _, ip := range addr.IP {
+				if ip.To4() == nil {
+					return true
+				}
+			}
+			return false
+		}
+		if hasv6(laddr) || hasv6(raddr) {
+			af = syscall.AF_INET6
+		}
+	case "sctp4":
+	case "sctp6":
+		af = syscall.AF_INET6
+	default:
+		return nil, fmt.Errorf("invalid net: %s", net)
+	}
+	sock, err := syscall.Socket(
+		af,
+		syscall.SOCK_STREAM,
+		syscall.IPPROTO_SCTP,
+	)
+	if err != nil {
+		return nil, err
+	}
+	err = setNumOstreams(sock, SCTP_MAX_STREAM)
+	if err != nil {
+		return nil, err
+	}
+	if laddr != nil {
+		err := SCTPBind(sock, laddr, SCTP_BINDX_ADD_ADDR)
+		if err != nil {
+			return nil, err
+		}
+	}
+	_, err = SCTPConnect(sock, raddr)
+	if err != nil {
+		return nil, err
+	}
+	return NewSCTPConn(sock, nil), nil
+}
diff --git a/vendor/github.com/ishidawataru/sctp/sctp_unsupported.go b/vendor/github.com/ishidawataru/sctp/sctp_unsupported.go
new file mode 100644
index 000000000..adcbf78b4
--- /dev/null
+++ b/vendor/github.com/ishidawataru/sctp/sctp_unsupported.go
@@ -0,0 +1,47 @@
+// +build !linux linux,386
+
+package sctp
+
+import (
+	"errors"
+	"net"
+	"runtime"
+)
+
+var ErrUnsupported = errors.New("SCTP is unsupported on " + runtime.GOOS + "/" + runtime.GOARCH)
+
+func setsockopt(fd int, optname, optval, optlen uintptr) (uintptr, uintptr, error) {
+	return 0, 0, ErrUnsupported
+}
+
+func getsockopt(fd int, optname, optval, optlen uintptr) (uintptr, uintptr, error) {
+	return 0, 0, ErrUnsupported
+}
+
+func (c *SCTPConn) SCTPWrite(b []byte, info *SndRcvInfo) (int, error) {
+	return 0, ErrUnsupported
+}
+
+func (c *SCTPConn) SCTPRead(b []byte) (int, *SndRcvInfo, error) {
+	return 0, nil, ErrUnsupported
+}
+
+func (c *SCTPConn) Close() error {
+	return ErrUnsupported
+}
+
+func ListenSCTP(net string, laddr *SCTPAddr) (*SCTPListener, error) {
+	return nil, ErrUnsupported
+}
+
+func (ln *SCTPListener) Accept() (net.Conn, error) {
+	return nil, ErrUnsupported
+}
+
+func (ln *SCTPListener) Close() error {
+	return ErrUnsupported
+}
+
+func DialSCTP(net string, laddr, raddr *SCTPAddr) (*SCTPConn, error) {
+	return nil, ErrUnsupported
+}