diff options
Diffstat (limited to 'vendor/github.com/vishvananda/netns/netns_linux.go')
-rw-r--r-- | vendor/github.com/vishvananda/netns/netns_linux.go | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/vendor/github.com/vishvananda/netns/netns_linux.go b/vendor/github.com/vishvananda/netns/netns_linux.go new file mode 100644 index 000000000..a267c7105 --- /dev/null +++ b/vendor/github.com/vishvananda/netns/netns_linux.go @@ -0,0 +1,224 @@ +// +build linux + +package netns + +import ( + "fmt" + "io/ioutil" + "os" + "path/filepath" + "runtime" + "strconv" + "strings" + "syscall" +) + +// SYS_SETNS syscall allows changing the namespace of the current process. +var SYS_SETNS = map[string]uintptr{ + "386": 346, + "amd64": 308, + "arm64": 268, + "arm": 375, + "mips": 4344, + "mipsle": 4344, + "ppc64": 350, + "ppc64le": 350, + "s390x": 339, +}[runtime.GOARCH] + +// Deprecated: use syscall pkg instead (go >= 1.5 needed). +const ( + CLONE_NEWUTS = 0x04000000 /* New utsname group? */ + CLONE_NEWIPC = 0x08000000 /* New ipcs */ + CLONE_NEWUSER = 0x10000000 /* New user namespace */ + CLONE_NEWPID = 0x20000000 /* New pid namespace */ + CLONE_NEWNET = 0x40000000 /* New network namespace */ + CLONE_IO = 0x80000000 /* Get io context */ +) + +// Setns sets namespace using syscall. Note that this should be a method +// in syscall but it has not been added. +func Setns(ns NsHandle, nstype int) (err error) { + _, _, e1 := syscall.Syscall(SYS_SETNS, uintptr(ns), uintptr(nstype), 0) + if e1 != 0 { + err = e1 + } + return +} + +// Set sets the current network namespace to the namespace represented +// by NsHandle. +func Set(ns NsHandle) (err error) { + return Setns(ns, CLONE_NEWNET) +} + +// New creates a new network namespace and returns a handle to it. +func New() (ns NsHandle, err error) { + if err := syscall.Unshare(CLONE_NEWNET); err != nil { + return -1, err + } + return Get() +} + +// Get gets a handle to the current threads network namespace. +func Get() (NsHandle, error) { + return GetFromThread(os.Getpid(), syscall.Gettid()) +} + +// GetFromPath gets a handle to a network namespace +// identified by the path +func GetFromPath(path string) (NsHandle, error) { + fd, err := syscall.Open(path, syscall.O_RDONLY, 0) + if err != nil { + return -1, err + } + return NsHandle(fd), nil +} + +// GetFromName gets a handle to a named network namespace such as one +// created by `ip netns add`. +func GetFromName(name string) (NsHandle, error) { + return GetFromPath(fmt.Sprintf("/var/run/netns/%s", name)) +} + +// GetFromPid gets a handle to the network namespace of a given pid. +func GetFromPid(pid int) (NsHandle, error) { + return GetFromPath(fmt.Sprintf("/proc/%d/ns/net", pid)) +} + +// GetFromThread gets a handle to the network namespace of a given pid and tid. +func GetFromThread(pid, tid int) (NsHandle, error) { + return GetFromPath(fmt.Sprintf("/proc/%d/task/%d/ns/net", pid, tid)) +} + +// GetFromDocker gets a handle to the network namespace of a docker container. +// Id is prefixed matched against the running docker containers, so a short +// identifier can be used as long as it isn't ambiguous. +func GetFromDocker(id string) (NsHandle, error) { + pid, err := getPidForContainer(id) + if err != nil { + return -1, err + } + return GetFromPid(pid) +} + +// borrowed from docker/utils/utils.go +func findCgroupMountpoint(cgroupType string) (string, error) { + output, err := ioutil.ReadFile("/proc/mounts") + if err != nil { + return "", err + } + + // /proc/mounts has 6 fields per line, one mount per line, e.g. + // cgroup /sys/fs/cgroup/devices cgroup rw,relatime,devices 0 0 + for _, line := range strings.Split(string(output), "\n") { + parts := strings.Split(line, " ") + if len(parts) == 6 && parts[2] == "cgroup" { + for _, opt := range strings.Split(parts[3], ",") { + if opt == cgroupType { + return parts[1], nil + } + } + } + } + + return "", fmt.Errorf("cgroup mountpoint not found for %s", cgroupType) +} + +// Returns the relative path to the cgroup docker is running in. +// borrowed from docker/utils/utils.go +// modified to get the docker pid instead of using /proc/self +func getThisCgroup(cgroupType string) (string, error) { + dockerpid, err := ioutil.ReadFile("/var/run/docker.pid") + if err != nil { + return "", err + } + result := strings.Split(string(dockerpid), "\n") + if len(result) == 0 || len(result[0]) == 0 { + return "", fmt.Errorf("docker pid not found in /var/run/docker.pid") + } + pid, err := strconv.Atoi(result[0]) + if err != nil { + return "", err + } + output, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/cgroup", pid)) + if err != nil { + return "", err + } + for _, line := range strings.Split(string(output), "\n") { + parts := strings.Split(line, ":") + // any type used by docker should work + if parts[1] == cgroupType { + return parts[2], nil + } + } + return "", fmt.Errorf("cgroup '%s' not found in /proc/%d/cgroup", cgroupType, pid) +} + +// Returns the first pid in a container. +// borrowed from docker/utils/utils.go +// modified to only return the first pid +// modified to glob with id +// modified to search for newer docker containers +func getPidForContainer(id string) (int, error) { + pid := 0 + + // memory is chosen randomly, any cgroup used by docker works + cgroupType := "memory" + + cgroupRoot, err := findCgroupMountpoint(cgroupType) + if err != nil { + return pid, err + } + + cgroupThis, err := getThisCgroup(cgroupType) + if err != nil { + return pid, err + } + + id += "*" + + attempts := []string{ + filepath.Join(cgroupRoot, cgroupThis, id, "tasks"), + // With more recent lxc versions use, cgroup will be in lxc/ + filepath.Join(cgroupRoot, cgroupThis, "lxc", id, "tasks"), + // With more recent docker, cgroup will be in docker/ + filepath.Join(cgroupRoot, cgroupThis, "docker", id, "tasks"), + // Even more recent docker versions under systemd use docker-<id>.scope/ + filepath.Join(cgroupRoot, "system.slice", "docker-"+id+".scope", "tasks"), + // Even more recent docker versions under cgroup/systemd/docker/<id>/ + filepath.Join(cgroupRoot, "..", "systemd", "docker", id, "tasks"), + } + + var filename string + for _, attempt := range attempts { + filenames, _ := filepath.Glob(attempt) + if len(filenames) > 1 { + return pid, fmt.Errorf("Ambiguous id supplied: %v", filenames) + } else if len(filenames) == 1 { + filename = filenames[0] + break + } + } + + if filename == "" { + return pid, fmt.Errorf("Unable to find container: %v", id[:len(id)-1]) + } + + output, err := ioutil.ReadFile(filename) + if err != nil { + return pid, err + } + + result := strings.Split(string(output), "\n") + if len(result) == 0 || len(result[0]) == 0 { + return pid, fmt.Errorf("No pid found for container") + } + + pid, err = strconv.Atoi(result[0]) + if err != nil { + return pid, fmt.Errorf("Invalid pid '%s': %s", result[0], err) + } + + return pid, nil +} |