-
Notifications
You must be signed in to change notification settings - Fork 18.6k
/
namespace_linux.go
681 lines (595 loc) · 16.8 KB
/
namespace_linux.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
package osl
import (
"errors"
"fmt"
"net"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"syscall"
"time"
"github.com/docker/docker/internal/unshare"
"github.com/docker/docker/libnetwork/ns"
"github.com/docker/docker/libnetwork/osl/kernel"
"github.com/docker/docker/libnetwork/types"
"github.com/sirupsen/logrus"
"github.com/vishvananda/netlink"
"github.com/vishvananda/netns"
"golang.org/x/sys/unix"
)
const defaultPrefix = "/var/run/docker"
func init() {
// Lock main() to the initial thread to exclude the goroutines spawned
// by func (*networkNamespace) InvokeFunc() or func setIPv6() below from
// being scheduled onto that thread. Changes to the network namespace of
// the initial thread alter /proc/self/ns/net, which would break any
// code which (incorrectly) assumes that that file is the network
// namespace for the thread it is currently executing on.
runtime.LockOSThread()
}
var (
once sync.Once
garbagePathMap = make(map[string]bool)
gpmLock sync.Mutex
gpmWg sync.WaitGroup
gpmCleanupPeriod = 60 * time.Second
gpmChan = make(chan chan struct{})
prefix = defaultPrefix
)
// The networkNamespace type is the linux implementation of the Sandbox
// interface. It represents a linux network namespace, and moves an interface
// into it when called on method AddInterface or sets the gateway etc.
type networkNamespace struct {
path string
iFaces []*nwIface
gw net.IP
gwv6 net.IP
staticRoutes []*types.StaticRoute
neighbors []*neigh
nextIfIndex map[string]int
isDefault bool
nlHandle *netlink.Handle
loV6Enabled bool
sync.Mutex
}
// SetBasePath sets the base url prefix for the ns path
func SetBasePath(path string) {
prefix = path
}
func basePath() string {
return filepath.Join(prefix, "netns")
}
func createBasePath() {
err := os.MkdirAll(basePath(), 0755)
if err != nil {
panic("Could not create net namespace path directory")
}
// Start the garbage collection go routine
go removeUnusedPaths()
}
func removeUnusedPaths() {
gpmLock.Lock()
period := gpmCleanupPeriod
gpmLock.Unlock()
ticker := time.NewTicker(period)
for {
var (
gc chan struct{}
gcOk bool
)
select {
case <-ticker.C:
case gc, gcOk = <-gpmChan:
}
gpmLock.Lock()
pathList := make([]string, 0, len(garbagePathMap))
for path := range garbagePathMap {
pathList = append(pathList, path)
}
garbagePathMap = make(map[string]bool)
gpmWg.Add(1)
gpmLock.Unlock()
for _, path := range pathList {
os.Remove(path)
}
gpmWg.Done()
if gcOk {
close(gc)
}
}
}
func addToGarbagePaths(path string) {
gpmLock.Lock()
garbagePathMap[path] = true
gpmLock.Unlock()
}
func removeFromGarbagePaths(path string) {
gpmLock.Lock()
delete(garbagePathMap, path)
gpmLock.Unlock()
}
// GC triggers garbage collection of namespace path right away
// and waits for it.
func GC() {
gpmLock.Lock()
if len(garbagePathMap) == 0 {
// No need for GC if map is empty
gpmLock.Unlock()
return
}
gpmLock.Unlock()
// if content exists in the garbage paths
// we can trigger GC to run, providing a
// channel to be notified on completion
waitGC := make(chan struct{})
gpmChan <- waitGC
// wait for GC completion
<-waitGC
}
// GenerateKey generates a sandbox key based on the passed
// container id.
func GenerateKey(containerID string) string {
maxLen := 12
// Read sandbox key from host for overlay
if strings.HasPrefix(containerID, "-") {
var (
index int
indexStr string
tmpkey string
)
dir, err := os.ReadDir(basePath())
if err != nil {
return ""
}
for _, v := range dir {
id := v.Name()
if strings.HasSuffix(id, containerID[:maxLen-1]) {
indexStr = strings.TrimSuffix(id, containerID[:maxLen-1])
tmpindex, err := strconv.Atoi(indexStr)
if err != nil {
return ""
}
if tmpindex > index {
index = tmpindex
tmpkey = id
}
}
}
containerID = tmpkey
if containerID == "" {
return ""
}
}
if len(containerID) < maxLen {
maxLen = len(containerID)
}
return basePath() + "/" + containerID[:maxLen]
}
// NewSandbox provides a new sandbox instance created in an os specific way
// provided a key which uniquely identifies the sandbox
func NewSandbox(key string, osCreate, isRestore bool) (Sandbox, error) {
if !isRestore {
err := createNetworkNamespace(key, osCreate)
if err != nil {
return nil, err
}
} else {
once.Do(createBasePath)
}
n := &networkNamespace{path: key, isDefault: !osCreate, nextIfIndex: make(map[string]int)}
sboxNs, err := netns.GetFromPath(n.path)
if err != nil {
return nil, fmt.Errorf("failed get network namespace %q: %v", n.path, err)
}
defer sboxNs.Close()
n.nlHandle, err = netlink.NewHandleAt(sboxNs, syscall.NETLINK_ROUTE)
if err != nil {
return nil, fmt.Errorf("failed to create a netlink handle: %v", err)
}
err = n.nlHandle.SetSocketTimeout(ns.NetlinkSocketsTimeout)
if err != nil {
logrus.Warnf("Failed to set the timeout on the sandbox netlink handle sockets: %v", err)
}
// In live-restore mode, IPV6 entries are getting cleaned up due to below code
// We should retain IPV6 configurations in live-restore mode when Docker Daemon
// comes back. It should work as it is on other cases
// As starting point, disable IPv6 on all interfaces
if !isRestore && !n.isDefault {
err = setIPv6(n.path, "all", false)
if err != nil {
logrus.Warnf("Failed to disable IPv6 on all interfaces on network namespace %q: %v", n.path, err)
}
}
if err = n.loopbackUp(); err != nil {
n.nlHandle.Close()
return nil, err
}
return n, nil
}
func (n *networkNamespace) InterfaceOptions() IfaceOptionSetter {
return n
}
func (n *networkNamespace) NeighborOptions() NeighborOptionSetter {
return n
}
func mountNetworkNamespace(basePath string, lnPath string) error {
return syscall.Mount(basePath, lnPath, "bind", syscall.MS_BIND, "")
}
// GetSandboxForExternalKey returns sandbox object for the supplied path
func GetSandboxForExternalKey(basePath string, key string) (Sandbox, error) {
if err := createNamespaceFile(key); err != nil {
return nil, err
}
if err := mountNetworkNamespace(basePath, key); err != nil {
return nil, err
}
n := &networkNamespace{path: key, nextIfIndex: make(map[string]int)}
sboxNs, err := netns.GetFromPath(n.path)
if err != nil {
return nil, fmt.Errorf("failed get network namespace %q: %v", n.path, err)
}
defer sboxNs.Close()
n.nlHandle, err = netlink.NewHandleAt(sboxNs, syscall.NETLINK_ROUTE)
if err != nil {
return nil, fmt.Errorf("failed to create a netlink handle: %v", err)
}
err = n.nlHandle.SetSocketTimeout(ns.NetlinkSocketsTimeout)
if err != nil {
logrus.Warnf("Failed to set the timeout on the sandbox netlink handle sockets: %v", err)
}
// As starting point, disable IPv6 on all interfaces
err = setIPv6(n.path, "all", false)
if err != nil {
logrus.Warnf("Failed to disable IPv6 on all interfaces on network namespace %q: %v", n.path, err)
}
if err = n.loopbackUp(); err != nil {
n.nlHandle.Close()
return nil, err
}
return n, nil
}
func createNetworkNamespace(path string, osCreate bool) error {
if err := createNamespaceFile(path); err != nil {
return err
}
do := func() error {
return mountNetworkNamespace(fmt.Sprintf("/proc/self/task/%d/ns/net", unix.Gettid()), path)
}
if osCreate {
return unshare.Go(unix.CLONE_NEWNET, do, nil)
}
return do()
}
func unmountNamespaceFile(path string) {
if _, err := os.Stat(path); err == nil {
if err := syscall.Unmount(path, syscall.MNT_DETACH); err != nil && !errors.Is(err, unix.EINVAL) {
logrus.WithError(err).Error("Error unmounting namespace file")
}
}
}
func createNamespaceFile(path string) (err error) {
var f *os.File
once.Do(createBasePath)
// Remove it from garbage collection list if present
removeFromGarbagePaths(path)
// If the path is there unmount it first
unmountNamespaceFile(path)
// wait for garbage collection to complete if it is in progress
// before trying to create the file.
gpmWg.Wait()
if f, err = os.Create(path); err == nil {
f.Close()
}
return err
}
func (n *networkNamespace) loopbackUp() error {
iface, err := n.nlHandle.LinkByName("lo")
if err != nil {
return err
}
return n.nlHandle.LinkSetUp(iface)
}
func (n *networkNamespace) GetLoopbackIfaceName() string {
return "lo"
}
func (n *networkNamespace) AddAliasIP(ifName string, ip *net.IPNet) error {
iface, err := n.nlHandle.LinkByName(ifName)
if err != nil {
return err
}
return n.nlHandle.AddrAdd(iface, &netlink.Addr{IPNet: ip})
}
func (n *networkNamespace) RemoveAliasIP(ifName string, ip *net.IPNet) error {
iface, err := n.nlHandle.LinkByName(ifName)
if err != nil {
return err
}
return n.nlHandle.AddrDel(iface, &netlink.Addr{IPNet: ip})
}
func (n *networkNamespace) DisableARPForVIP(srcName string) (Err error) {
dstName := ""
for _, i := range n.Interfaces() {
if i.SrcName() == srcName {
dstName = i.DstName()
break
}
}
if dstName == "" {
return fmt.Errorf("failed to find interface %s in sandbox", srcName)
}
err := n.InvokeFunc(func() {
path := filepath.Join("/proc/sys/net/ipv4/conf", dstName, "arp_ignore")
if err := os.WriteFile(path, []byte{'1', '\n'}, 0644); err != nil {
Err = fmt.Errorf("Failed to set %s to 1: %v", path, err)
return
}
path = filepath.Join("/proc/sys/net/ipv4/conf", dstName, "arp_announce")
if err := os.WriteFile(path, []byte{'2', '\n'}, 0644); err != nil {
Err = fmt.Errorf("Failed to set %s to 2: %v", path, err)
return
}
})
if err != nil {
return err
}
return
}
func (n *networkNamespace) InvokeFunc(f func()) error {
path := n.nsPath()
newNS, err := netns.GetFromPath(path)
if err != nil {
return fmt.Errorf("failed get network namespace %q: %w", path, err)
}
defer newNS.Close()
done := make(chan error, 1)
go func() {
runtime.LockOSThread()
// InvokeFunc() could have been called from a goroutine with
// tampered thread state, e.g. from another InvokeFunc()
// callback. The outer goroutine's thread state cannot be
// trusted.
origNS, err := netns.Get()
if err != nil {
runtime.UnlockOSThread()
done <- fmt.Errorf("failed to get original network namespace: %w", err)
return
}
defer origNS.Close()
if err := netns.Set(newNS); err != nil {
runtime.UnlockOSThread()
done <- err
return
}
defer func() {
close(done)
if err := netns.Set(origNS); err != nil {
logrus.WithError(err).Warn("failed to restore thread's network namespace")
// Recover from the error by leaving this goroutine locked to
// the thread. The runtime will terminate the thread and replace
// it with a clean one when this goroutine returns.
} else {
runtime.UnlockOSThread()
}
}()
f()
}()
return <-done
}
func (n *networkNamespace) nsPath() string {
n.Lock()
defer n.Unlock()
return n.path
}
func (n *networkNamespace) Info() Info {
return n
}
func (n *networkNamespace) Key() string {
return n.path
}
func (n *networkNamespace) Destroy() error {
if n.nlHandle != nil {
n.nlHandle.Close()
}
// Assuming no running process is executing in this network namespace,
// unmounting is sufficient to destroy it.
if err := syscall.Unmount(n.path, syscall.MNT_DETACH); err != nil {
return err
}
// Stash it into the garbage collection list
addToGarbagePaths(n.path)
return nil
}
// Restore restore the network namespace
func (n *networkNamespace) Restore(ifsopt map[string][]IfaceOption, routes []*types.StaticRoute, gw net.IP, gw6 net.IP) error {
// restore interfaces
for name, opts := range ifsopt {
if !strings.Contains(name, "+") {
return fmt.Errorf("wrong iface name in restore osl sandbox interface: %s", name)
}
seps := strings.Split(name, "+")
srcName := seps[0]
dstPrefix := seps[1]
i := &nwIface{srcName: srcName, dstName: dstPrefix, ns: n}
i.processInterfaceOptions(opts...)
if i.master != "" {
i.dstMaster = n.findDst(i.master, true)
if i.dstMaster == "" {
return fmt.Errorf("could not find an appropriate master %q for %q",
i.master, i.srcName)
}
}
if n.isDefault {
i.dstName = i.srcName
} else {
links, err := n.nlHandle.LinkList()
if err != nil {
return fmt.Errorf("failed to retrieve list of links in network namespace %q during restore", n.path)
}
// due to the docker network connect/disconnect, so the dstName should
// restore from the namespace
for _, link := range links {
addrs, err := n.nlHandle.AddrList(link, netlink.FAMILY_V4)
if err != nil {
return err
}
ifaceName := link.Attrs().Name
if strings.HasPrefix(ifaceName, "vxlan") {
if i.dstName == "vxlan" {
i.dstName = ifaceName
break
}
}
// find the interface name by ip
if i.address != nil {
for _, addr := range addrs {
if addr.IPNet.String() == i.address.String() {
i.dstName = ifaceName
break
}
continue
}
if i.dstName == ifaceName {
break
}
}
// This is to find the interface name of the pair in overlay sandbox
if strings.HasPrefix(ifaceName, "veth") {
if i.master != "" && i.dstName == "veth" {
i.dstName = ifaceName
}
}
}
var index int
indexStr := strings.TrimPrefix(i.dstName, dstPrefix)
if indexStr != "" {
index, err = strconv.Atoi(indexStr)
if err != nil {
return err
}
}
index++
n.Lock()
if index > n.nextIfIndex[dstPrefix] {
n.nextIfIndex[dstPrefix] = index
}
n.iFaces = append(n.iFaces, i)
n.Unlock()
}
}
// restore routes
for _, r := range routes {
n.Lock()
n.staticRoutes = append(n.staticRoutes, r)
n.Unlock()
}
// restore gateway
if len(gw) > 0 {
n.Lock()
n.gw = gw
n.Unlock()
}
if len(gw6) > 0 {
n.Lock()
n.gwv6 = gw6
n.Unlock()
}
return nil
}
// Checks whether IPv6 needs to be enabled/disabled on the loopback interface
func (n *networkNamespace) checkLoV6() {
var (
enable = false
action = "disable"
)
n.Lock()
for _, iface := range n.iFaces {
if iface.AddressIPv6() != nil {
enable = true
action = "enable"
break
}
}
n.Unlock()
if n.loV6Enabled == enable {
return
}
if err := setIPv6(n.path, "lo", enable); err != nil {
logrus.Warnf("Failed to %s IPv6 on loopback interface on network namespace %q: %v", action, n.path, err)
}
n.loV6Enabled = enable
}
func setIPv6(nspath, iface string, enable bool) error {
origNS, err := netns.Get()
if err != nil {
return fmt.Errorf("failed to get current network namespace: %w", err)
}
defer origNS.Close()
namespace, err := netns.GetFromPath(nspath)
if err != nil {
return fmt.Errorf("failed get network namespace %q: %w", nspath, err)
}
defer namespace.Close()
errCh := make(chan error, 1)
go func() {
defer close(errCh)
runtime.LockOSThread()
if err = netns.Set(namespace); err != nil {
errCh <- fmt.Errorf("setting into container netns %q failed: %w", nspath, err)
return
}
defer func() {
if err := netns.Set(origNS); err != nil {
logrus.WithError(err).Error("libnetwork: restoring thread network namespace failed")
// The error is only fatal for the current thread. Keep this
// goroutine locked to the thread to make the runtime replace it
// with a clean thread once this goroutine returns.
} else {
runtime.UnlockOSThread()
}
}()
var (
action = "disable"
value = byte('1')
path = fmt.Sprintf("/proc/sys/net/ipv6/conf/%s/disable_ipv6", iface)
)
if enable {
action = "enable"
value = '0'
}
if _, err := os.Stat(path); err != nil {
if os.IsNotExist(err) {
logrus.WithError(err).Warn("Cannot configure IPv6 forwarding on container interface. Has IPv6 been disabled in this node's kernel?")
return
}
errCh <- err
return
}
if err = os.WriteFile(path, []byte{value, '\n'}, 0o644); err != nil {
errCh <- fmt.Errorf("failed to %s IPv6 forwarding for container's interface %s: %w", action, iface, err)
return
}
}()
return <-errCh
}
// ApplyOSTweaks applies linux configs on the sandbox
func (n *networkNamespace) ApplyOSTweaks(types []SandboxType) {
for _, t := range types {
switch t {
case SandboxTypeLoadBalancer, SandboxTypeIngress:
kernel.ApplyOSTweaks(map[string]*kernel.OSValue{
// disables any special handling on port reuse of existing IPVS connection table entries
// more info: https://github.com/torvalds/linux/blame/v5.15/Documentation/networking/ipvs-sysctl.rst#L32
"net.ipv4.vs.conn_reuse_mode": {Value: "0", CheckFn: nil},
// expires connection from the IPVS connection table when the backend is not available
// more info: https://github.com/torvalds/linux/blame/v5.15/Documentation/networking/ipvs-sysctl.rst#L133
"net.ipv4.vs.expire_nodest_conn": {Value: "1", CheckFn: nil},
// expires persistent connections to destination servers with weights set to 0
// more info: https://github.com/torvalds/linux/blame/v5.15/Documentation/networking/ipvs-sysctl.rst#L151
"net.ipv4.vs.expire_quiescent_template": {Value: "1", CheckFn: nil},
})
}
}
}