RepoMirrors
/
netns
mirror of https://github.com/vishvananda/netns
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Initial commit of netns package

This commit is contained in:
Vishvananda Ishaya 2014-08-31 13:47:35 -07:00
commit b801b0b909
8 changed files with 570 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

192
LICENSE Normal file
View File

@ -0,0 +1,192 @@
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
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
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
modifications, and in Source or Object form, provided that You
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
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
include a readable copy of the attribution notices contained
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
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
Copyright 2014 Vishvananda Ishaya.
Copyright 2014 Docker, Inc.
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.

49
README.md Normal file
View File

@ -0,0 +1,49 @@
# netns - network namespaces in go #
The netns package provides an ultra-simple interface for handling
network namespaces in go. Changing namespaces requires elevated
privileges, so in most cases this code needs to be run as root.
## Local Build and Test ##
You can use go get command:
go get github.com/vishvananda/netns
Testing (requires root):
sudo -E go test github.com/vishvananda/netns
## Example ##
```go
package main
import (
"net"
"runtime"
"github.com/vishvananada/netns"
)
func main() {
// Lock the OS Thread so we don't accidentally switch namespaces
runtime.LockOSThread()
defer runtime.UnlockOSThread()
// Save the current network namespace
origns, _ := netns.Get()
defer origns.Close()
// Create a new network namespace
newns, _ := netns.New()
defer newns.Close()
// Do something with tne network namespace
ifaces, _ := net.Interfaces()
fmt.Printf("Interfaces: %v\n", ifaces)
// Switch back to the original namespace
netns.Set(origns)
}
```

242
netns_linux.go Normal file
View File

@ -0,0 +1,242 @@
// Package netns allows ultra-simple network namespace handling. NsHandles
// can be retrieved and set. Note that the current namespace is thread
// local so actions that set and reset namespaces should use LockOSThread
// to make sure the namespace doesn't change due to a goroutine switch.
// It is best to close NsHandles when you are done with them. This can be
// accomplished via a `defer ns.Close()` on the handle. Changing namespaces
// requires elevated privileges, so in most cases this code needs to be run
// as root.
package netns
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
)
const (
// These constants belong in the syscall library but have not been
// added yet.
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
}
// NsHandle is a handle to a network namespace. It can be cast directly
// to an int and used as a file descriptor.
type NsHandle int
// Equal determines if two network handles refer to the same network
// namespace. This is done by comparing the device and inode that the
// file descripors point to.
func (ns NsHandle) Equal(other NsHandle) bool {
var s1, s2 syscall.Stat_t
if err := syscall.Fstat(int(ns), &s1); err != nil {
return false
}
if err := syscall.Fstat(int(other), &s2); err != nil {
return false
}
return (s1.Dev == s2.Dev) && (s1.Ino == s2.Ino)
}
// String shows the file descriptor number and its dev and inode.
func (ns NsHandle) String() string {
var s syscall.Stat_t
if err := syscall.Fstat(int(ns), &s); err != nil {
return fmt.Sprintf("NS(%d: unknown)", ns)
}
return fmt.Sprintf("NS(%d: %d, %d)", ns, s.Dev, s.Ino)
}
// IsOpen returns true if Close() has not been called.
func (ns NsHandle) IsOpen() bool {
return ns != -1
}
// Close closes the NsHandle and resets its file descriptor to -1.
// It is not safe to use an NsHandle after Close() is called.
func (ns *NsHandle) Close() error {
if err := syscall.Close(int(*ns)); err != nil {
return err
}
(*ns) = -1
return nil
}
// 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 GetFromPid(os.Getpid())
}
// GetFromName gets a handle to a named network namespace such as one
// created by `ip netns add`.
func GetFromName(name string) (NsHandle, error) {
fd, err := syscall.Open(fmt.Sprintf("/var/run/netns/%s", name), syscall.O_RDONLY, 0)
if err != nil {
return -1, err
}
return NsHandle(fd), nil
}
// GetFromName gets a handle to the network namespace of a given pid.
func GetFromPid(pid int) (NsHandle, error) {
fd, err := syscall.Open(fmt.Sprintf("/proc/%d/ns/net", pid), syscall.O_RDONLY, 0)
if err != nil {
return -1, err
}
return NsHandle(fd), nil
}
// GetFromName 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])
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
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 += "*"
filename := filepath.Join(cgroupRoot, cgroupThis, id, "tasks")
filenames, _ := filepath.Glob(filename)
if len(filenames) > 1 {
return pid, fmt.Errorf("Ambiguous id supplied: %v", filenames)
} else if len(filenames) == 1 {
filename = filenames[0]
}
if _, err := os.Stat(filename); os.IsNotExist(err) {
// With more recent lxc versions use, cgroup will be in lxc/
filename = filepath.Join(cgroupRoot, cgroupThis, "lxc", id, "tasks")
filenames, _ = filepath.Glob(filename)
if len(filenames) > 1 {
return pid, fmt.Errorf("Ambiguous id supplied: %v", filenames)
} else if len(filenames) == 1 {
filename = filenames[0]
} else {
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
}

5
netns_linux_386.go Normal file
View File

@ -0,0 +1,5 @@
package netns
const (
SYS_SETNS = 346
)

5
netns_linux_amd.go Normal file
View File

@ -0,0 +1,5 @@
package netns
const (
SYS_SETNS = 308
)

5
netns_linux_arm.go Normal file
View File

@ -0,0 +1,5 @@
package netns
const (
SYS_SETNS = 374
)

37
netns_test.go Normal file
View File

@ -0,0 +1,37 @@
package netns
import (
"runtime"
"testing"
)
func TestGetNewSetDelete(t *testing.T) {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
origns, err := Get()
if err != nil {
t.Fatal(err)
}
newns, err := New()
if err != nil {
t.Fatal(err)
}
if origns.Equal(newns) {
t.Fatal("New ns failed")
}
if err := Set(origns); err != nil {
t.Fatal(err)
}
newns.Close()
if newns.IsOpen() {
t.Fatal("newns still open after close", newns)
}
ns, err := Get()
if err != nil {
t.Fatal(err)
}
if !ns.Equal(origns) {
t.Fatal("Reset ns failed", origns, newns, ns)
}
}

35
netns_unspecified.go Normal file
View File

@ -0,0 +1,35 @@
// +build !linux
package netns
import (
"errors"
)
var (
ErrNotImplemented = errors.New("not implemented")
)
func Set(ns Namespace) (err error) {
return ErrNotImplemented
}
func New() (ns Namespace, err error) {
return -1, ErrNotImplemented
}
func Get() (Namespace, error) {
return -1, ErrNotImplemented
}
func GetFromName(name string) (Namespace, error) {
return -1, ErrNotImplemented
}
func GetFromPid(pid int) (Namespace, error) {
return -1, ErrNotImplemented
}
func GetFromDocker(id string) (Namespace, error) {
return -1, ErrNotImplemented
}