diff options
Diffstat (limited to 'vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go')
-rw-r--r-- | vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go | 93 |
1 files changed, 91 insertions, 2 deletions
diff --git a/vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go b/vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go index 31ad5f622..4ce989467 100644 --- a/vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go +++ b/vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go @@ -15,8 +15,10 @@ package ns import ( + "crypto/rand" "fmt" "os" + "path" "runtime" "sync" "syscall" @@ -36,6 +38,82 @@ func getCurrentThreadNetNSPath() string { return fmt.Sprintf("/proc/%d/task/%d/ns/net", os.Getpid(), unix.Gettid()) } +// Creates a new persistent network namespace and returns an object +// representing that namespace, without switching to it +func NewNS() (NetNS, error) { + const nsRunDir = "/var/run/netns" + + b := make([]byte, 16) + _, err := rand.Reader.Read(b) + if err != nil { + return nil, fmt.Errorf("failed to generate random netns name: %v", err) + } + + err = os.MkdirAll(nsRunDir, 0755) + if err != nil { + return nil, err + } + + // create an empty file at the mount point + nsName := fmt.Sprintf("cni-%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:]) + nsPath := path.Join(nsRunDir, nsName) + mountPointFd, err := os.Create(nsPath) + if err != nil { + return nil, err + } + mountPointFd.Close() + + // Ensure the mount point is cleaned up on errors; if the namespace + // was successfully mounted this will have no effect because the file + // is in-use + defer os.RemoveAll(nsPath) + + var wg sync.WaitGroup + wg.Add(1) + + // do namespace work in a dedicated goroutine, so that we can safely + // Lock/Unlock OSThread without upsetting the lock/unlock state of + // the caller of this function + var fd *os.File + go (func() { + defer wg.Done() + runtime.LockOSThread() + + var origNS NetNS + origNS, err = GetNS(getCurrentThreadNetNSPath()) + if err != nil { + return + } + defer origNS.Close() + + // create a new netns on the current thread + err = unix.Unshare(unix.CLONE_NEWNET) + if err != nil { + return + } + defer origNS.Set() + + // bind mount the new netns from the current thread onto the mount point + err = unix.Mount(getCurrentThreadNetNSPath(), nsPath, "none", unix.MS_BIND, "") + if err != nil { + return + } + + fd, err = os.Open(nsPath) + if err != nil { + return + } + })() + wg.Wait() + + if err != nil { + unix.Unmount(nsPath, unix.MNT_DETACH) + return nil, fmt.Errorf("failed to create namespace: %v", err) + } + + return &netNS{file: fd, mounted: true}, nil +} + func (ns *netNS) Close() error { if err := ns.errorIfClosed(); err != nil { return err @@ -46,6 +124,16 @@ func (ns *netNS) Close() error { } ns.closed = true + if ns.mounted { + if err := unix.Unmount(ns.file.Name(), unix.MNT_DETACH); err != nil { + return fmt.Errorf("Failed to unmount namespace %s: %v", ns.file.Name(), err) + } + if err := os.RemoveAll(ns.file.Name()); err != nil { + return fmt.Errorf("Failed to clean up namespace %s: %v", ns.file.Name(), err) + } + ns.mounted = false + } + return nil } @@ -92,8 +180,9 @@ type NetNS interface { } type netNS struct { - file *os.File - closed bool + file *os.File + mounted bool + closed bool } // netNS implements the NetNS interface |