forked from nicocha30/gvisor-ligolo
-
Notifications
You must be signed in to change notification settings - Fork 0
/
targets.go
661 lines (560 loc) · 19 KB
/
targets.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
// Copyright 2020 The gVisor Authors.
//
// 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.
package netfilter
import (
"encoding/binary"
"fmt"
"github.com/ttpreport/gvisor-ligolo/pkg/abi/linux"
"github.com/ttpreport/gvisor-ligolo/pkg/hostarch"
"github.com/ttpreport/gvisor-ligolo/pkg/marshal"
"github.com/ttpreport/gvisor-ligolo/pkg/syserr"
"github.com/ttpreport/gvisor-ligolo/pkg/tcpip"
"github.com/ttpreport/gvisor-ligolo/pkg/tcpip/header"
"github.com/ttpreport/gvisor-ligolo/pkg/tcpip/stack"
)
// ErrorTargetName is used to mark targets as error targets. Error targets
// shouldn't be reached - an error has occurred if we fall through to one.
const ErrorTargetName = "ERROR"
// RedirectTargetName is used to mark targets as redirect targets. Redirect
// targets should be reached for only NAT and Mangle tables. These targets will
// change the destination port and/or IP for packets.
const RedirectTargetName = "REDIRECT"
// SNATTargetName is used to mark targets as SNAT targets. SNAT targets should
// be reached for only NAT table. These targets will change the source port
// and/or IP for packets.
const SNATTargetName = "SNAT"
func init() {
// Standard targets include ACCEPT, DROP, RETURN, and JUMP.
registerTargetMaker(&standardTargetMaker{
NetworkProtocol: header.IPv4ProtocolNumber,
})
registerTargetMaker(&standardTargetMaker{
NetworkProtocol: header.IPv6ProtocolNumber,
})
// Both user chains and actual errors are represented in iptables by
// error targets.
registerTargetMaker(&errorTargetMaker{
NetworkProtocol: header.IPv4ProtocolNumber,
})
registerTargetMaker(&errorTargetMaker{
NetworkProtocol: header.IPv6ProtocolNumber,
})
registerTargetMaker(&redirectTargetMaker{
NetworkProtocol: header.IPv4ProtocolNumber,
})
registerTargetMaker(&nfNATTargetMaker{
NetworkProtocol: header.IPv6ProtocolNumber,
})
registerTargetMaker(&snatTargetMakerV4{
NetworkProtocol: header.IPv4ProtocolNumber,
})
registerTargetMaker(&snatTargetMakerV6{
NetworkProtocol: header.IPv6ProtocolNumber,
})
}
// The stack package provides some basic, useful targets for us. The following
// types wrap them for compatibility with the extension system.
type acceptTarget struct {
stack.AcceptTarget
}
func (at *acceptTarget) id() targetID {
return targetID{
networkProtocol: at.NetworkProtocol,
}
}
type dropTarget struct {
stack.DropTarget
}
func (dt *dropTarget) id() targetID {
return targetID{
networkProtocol: dt.NetworkProtocol,
}
}
type errorTarget struct {
stack.ErrorTarget
}
func (et *errorTarget) id() targetID {
return targetID{
name: ErrorTargetName,
networkProtocol: et.NetworkProtocol,
}
}
type userChainTarget struct {
stack.UserChainTarget
}
func (uc *userChainTarget) id() targetID {
return targetID{
name: ErrorTargetName,
networkProtocol: uc.NetworkProtocol,
}
}
type returnTarget struct {
stack.ReturnTarget
}
func (rt *returnTarget) id() targetID {
return targetID{
networkProtocol: rt.NetworkProtocol,
}
}
type redirectTarget struct {
stack.RedirectTarget
// addr must be (un)marshalled when reading and writing the target to
// userspace, but does not affect behavior.
addr tcpip.Address
}
func (rt *redirectTarget) id() targetID {
return targetID{
name: RedirectTargetName,
networkProtocol: rt.NetworkProtocol,
}
}
type snatTarget struct {
stack.SNATTarget
}
func (st *snatTarget) id() targetID {
return targetID{
name: SNATTargetName,
networkProtocol: st.NetworkProtocol,
}
}
type standardTargetMaker struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (sm *standardTargetMaker) id() targetID {
// Standard targets have the empty string as a name and no revisions.
return targetID{
networkProtocol: sm.NetworkProtocol,
}
}
func (*standardTargetMaker) marshal(target target) []byte {
// Translate verdicts the same way as the iptables tool.
var verdict int32
switch tg := target.(type) {
case *acceptTarget:
verdict = -linux.NF_ACCEPT - 1
case *dropTarget:
verdict = -linux.NF_DROP - 1
case *returnTarget:
verdict = linux.NF_RETURN
case *JumpTarget:
verdict = int32(tg.Offset)
default:
panic(fmt.Errorf("unknown target of type %T", target))
}
// The target's name will be the empty string.
xt := linux.XTStandardTarget{
Target: linux.XTEntryTarget{
TargetSize: linux.SizeOfXTStandardTarget,
},
Verdict: verdict,
}
return marshal.Marshal(&xt)
}
func (*standardTargetMaker) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if len(buf) != linux.SizeOfXTStandardTarget {
nflog("buf has wrong size for standard target %d", len(buf))
return nil, syserr.ErrInvalidArgument
}
var standardTarget linux.XTStandardTarget
standardTarget.UnmarshalUnsafe(buf)
if standardTarget.Verdict < 0 {
// A Verdict < 0 indicates a non-jump verdict.
return translateToStandardTarget(standardTarget.Verdict, filter.NetworkProtocol())
}
// A verdict >= 0 indicates a jump.
return &JumpTarget{
Offset: uint32(standardTarget.Verdict),
NetworkProtocol: filter.NetworkProtocol(),
}, nil
}
type errorTargetMaker struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (em *errorTargetMaker) id() targetID {
// Error targets have no revision.
return targetID{
name: ErrorTargetName,
networkProtocol: em.NetworkProtocol,
}
}
func (*errorTargetMaker) marshal(target target) []byte {
var errorName string
switch tg := target.(type) {
case *errorTarget:
errorName = ErrorTargetName
case *userChainTarget:
errorName = tg.Name
default:
panic(fmt.Sprintf("errorMakerTarget cannot marshal unknown type %T", target))
}
// This is an error target named error
xt := linux.XTErrorTarget{
Target: linux.XTEntryTarget{
TargetSize: linux.SizeOfXTErrorTarget,
},
}
copy(xt.Name[:], errorName)
copy(xt.Target.Name[:], ErrorTargetName)
return marshal.Marshal(&xt)
}
func (*errorTargetMaker) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if len(buf) != linux.SizeOfXTErrorTarget {
nflog("buf has insufficient size for error target %d", len(buf))
return nil, syserr.ErrInvalidArgument
}
var errTgt linux.XTErrorTarget
errTgt.UnmarshalUnsafe(buf)
// Error targets are used in 2 cases:
// * An actual error case. These rules have an error named
// ErrorTargetName. The last entry of the table is usually an error
// case to catch any packets that somehow fall through every rule.
// * To mark the start of a user defined chain. These
// rules have an error with the name of the chain.
switch name := errTgt.Name.String(); name {
case ErrorTargetName:
return &errorTarget{stack.ErrorTarget{
NetworkProtocol: filter.NetworkProtocol(),
}}, nil
default:
// User defined chain.
return &userChainTarget{stack.UserChainTarget{
Name: name,
NetworkProtocol: filter.NetworkProtocol(),
}}, nil
}
}
type redirectTargetMaker struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (rm *redirectTargetMaker) id() targetID {
return targetID{
name: RedirectTargetName,
networkProtocol: rm.NetworkProtocol,
}
}
func (*redirectTargetMaker) marshal(target target) []byte {
rt := target.(*redirectTarget)
// This is a redirect target named redirect
xt := linux.XTRedirectTarget{
Target: linux.XTEntryTarget{
TargetSize: linux.SizeOfXTRedirectTarget,
},
}
copy(xt.Target.Name[:], RedirectTargetName)
xt.NfRange.RangeSize = 1
xt.NfRange.RangeIPV4.Flags |= linux.NF_NAT_RANGE_PROTO_SPECIFIED
xt.NfRange.RangeIPV4.MinPort = htons(rt.Port)
xt.NfRange.RangeIPV4.MaxPort = xt.NfRange.RangeIPV4.MinPort
return marshal.Marshal(&xt)
}
func (*redirectTargetMaker) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if len(buf) < linux.SizeOfXTRedirectTarget {
nflog("redirectTargetMaker: buf has insufficient size for redirect target %d", len(buf))
return nil, syserr.ErrInvalidArgument
}
if p := filter.Protocol; p != header.TCPProtocolNumber && p != header.UDPProtocolNumber {
nflog("redirectTargetMaker: bad proto %d", p)
return nil, syserr.ErrInvalidArgument
}
var rt linux.XTRedirectTarget
rt.UnmarshalUnsafe(buf)
// Copy linux.XTRedirectTarget to stack.RedirectTarget.
target := redirectTarget{RedirectTarget: stack.RedirectTarget{
NetworkProtocol: filter.NetworkProtocol(),
}}
// RangeSize should be 1.
nfRange := rt.NfRange
if nfRange.RangeSize != 1 {
nflog("redirectTargetMaker: bad rangesize %d", nfRange.RangeSize)
return nil, syserr.ErrInvalidArgument
}
// Also check if we need to map ports or IP.
// For now, redirect target only supports destination port change.
// Port range and IP range are not supported yet.
if nfRange.RangeIPV4.Flags != linux.NF_NAT_RANGE_PROTO_SPECIFIED {
nflog("redirectTargetMaker: invalid range flags %d", nfRange.RangeIPV4.Flags)
return nil, syserr.ErrInvalidArgument
}
if nfRange.RangeIPV4.MinPort != nfRange.RangeIPV4.MaxPort {
nflog("redirectTargetMaker: MinPort != MaxPort (%d, %d)", nfRange.RangeIPV4.MinPort, nfRange.RangeIPV4.MaxPort)
return nil, syserr.ErrInvalidArgument
}
if nfRange.RangeIPV4.MinIP != nfRange.RangeIPV4.MaxIP {
nflog("redirectTargetMaker: MinIP != MaxIP (%d, %d)", nfRange.RangeIPV4.MinPort, nfRange.RangeIPV4.MaxPort)
return nil, syserr.ErrInvalidArgument
}
target.addr = tcpip.AddrFrom4(nfRange.RangeIPV4.MinIP)
target.Port = ntohs(nfRange.RangeIPV4.MinPort)
return &target, nil
}
// +marshal
type nfNATTarget struct {
Target linux.XTEntryTarget
Range linux.NFNATRange
}
const nfNATMarshalledSize = linux.SizeOfXTEntryTarget + linux.SizeOfNFNATRange
type nfNATTargetMaker struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (rm *nfNATTargetMaker) id() targetID {
return targetID{
name: RedirectTargetName,
networkProtocol: rm.NetworkProtocol,
}
}
func (*nfNATTargetMaker) marshal(target target) []byte {
rt := target.(*redirectTarget)
nt := nfNATTarget{
Target: linux.XTEntryTarget{
TargetSize: nfNATMarshalledSize,
},
Range: linux.NFNATRange{
Flags: linux.NF_NAT_RANGE_PROTO_SPECIFIED,
},
}
copy(nt.Target.Name[:], RedirectTargetName)
copy(nt.Range.MinAddr[:], rt.addr.AsSlice())
copy(nt.Range.MaxAddr[:], rt.addr.AsSlice())
nt.Range.MinProto = htons(rt.Port)
nt.Range.MaxProto = nt.Range.MinProto
return marshal.Marshal(&nt)
}
func (*nfNATTargetMaker) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if size := nfNATMarshalledSize; len(buf) < size {
nflog("nfNATTargetMaker: buf has insufficient size (%d) for nfNAT target (%d)", len(buf), size)
return nil, syserr.ErrInvalidArgument
}
if p := filter.Protocol; p != header.TCPProtocolNumber && p != header.UDPProtocolNumber {
nflog("nfNATTargetMaker: bad proto %d", p)
return nil, syserr.ErrInvalidArgument
}
var natRange linux.NFNATRange
natRange.UnmarshalUnsafe(buf[linux.SizeOfXTEntryTarget:])
// We don't support port or address ranges.
if natRange.MinAddr != natRange.MaxAddr {
nflog("nfNATTargetMaker: MinAddr and MaxAddr are different")
return nil, syserr.ErrInvalidArgument
}
if natRange.MinProto != natRange.MaxProto {
nflog("nfNATTargetMaker: MinProto and MaxProto are different")
return nil, syserr.ErrInvalidArgument
}
// For now, redirect target only supports destination change.
if natRange.Flags != linux.NF_NAT_RANGE_PROTO_SPECIFIED {
nflog("nfNATTargetMaker: invalid range flags %d", natRange.Flags)
return nil, syserr.ErrInvalidArgument
}
target := redirectTarget{
RedirectTarget: stack.RedirectTarget{
NetworkProtocol: filter.NetworkProtocol(),
Port: ntohs(natRange.MinProto),
},
addr: tcpip.AddrFrom16(natRange.MinAddr),
}
return &target, nil
}
type snatTargetMakerV4 struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (st *snatTargetMakerV4) id() targetID {
return targetID{
name: SNATTargetName,
networkProtocol: st.NetworkProtocol,
}
}
func (*snatTargetMakerV4) marshal(target target) []byte {
st := target.(*snatTarget)
// This is a snat target named snat.
xt := linux.XTSNATTarget{
Target: linux.XTEntryTarget{
TargetSize: linux.SizeOfXTSNATTarget,
},
}
copy(xt.Target.Name[:], SNATTargetName)
xt.NfRange.RangeSize = 1
xt.NfRange.RangeIPV4.Flags |= linux.NF_NAT_RANGE_MAP_IPS | linux.NF_NAT_RANGE_PROTO_SPECIFIED
xt.NfRange.RangeIPV4.MinPort = htons(st.Port)
xt.NfRange.RangeIPV4.MaxPort = xt.NfRange.RangeIPV4.MinPort
copy(xt.NfRange.RangeIPV4.MinIP[:], st.Addr.AsSlice())
copy(xt.NfRange.RangeIPV4.MaxIP[:], st.Addr.AsSlice())
return marshal.Marshal(&xt)
}
func (*snatTargetMakerV4) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if len(buf) < linux.SizeOfXTSNATTarget {
nflog("snatTargetMakerV4: buf has insufficient size for snat target %d", len(buf))
return nil, syserr.ErrInvalidArgument
}
if p := filter.Protocol; p != header.TCPProtocolNumber && p != header.UDPProtocolNumber {
nflog("snatTargetMakerV4: bad proto %d", p)
return nil, syserr.ErrInvalidArgument
}
var st linux.XTSNATTarget
st.UnmarshalUnsafe(buf)
// Copy linux.XTSNATTarget to stack.SNATTarget.
target := snatTarget{SNATTarget: stack.SNATTarget{
NetworkProtocol: filter.NetworkProtocol(),
}}
// RangeSize should be 1.
nfRange := st.NfRange
if nfRange.RangeSize != 1 {
nflog("snatTargetMakerV4: bad rangesize %d", nfRange.RangeSize)
return nil, syserr.ErrInvalidArgument
}
// TODO(gvisor.dev/issue/5772): If the rule doesn't specify the source port,
// choose one automatically.
if nfRange.RangeIPV4.MinPort == 0 {
nflog("snatTargetMakerV4: snat target needs to specify a non-zero port")
return nil, syserr.ErrInvalidArgument
}
if nfRange.RangeIPV4.MinPort != nfRange.RangeIPV4.MaxPort {
nflog("snatTargetMakerV4: MinPort != MaxPort (%d, %d)", nfRange.RangeIPV4.MinPort, nfRange.RangeIPV4.MaxPort)
return nil, syserr.ErrInvalidArgument
}
if nfRange.RangeIPV4.MinIP != nfRange.RangeIPV4.MaxIP {
nflog("snatTargetMakerV4: MinIP != MaxIP (%d, %d)", nfRange.RangeIPV4.MinPort, nfRange.RangeIPV4.MaxPort)
return nil, syserr.ErrInvalidArgument
}
target.Addr = tcpip.AddrFrom4(nfRange.RangeIPV4.MinIP)
target.Port = ntohs(nfRange.RangeIPV4.MinPort)
return &target, nil
}
type snatTargetMakerV6 struct {
NetworkProtocol tcpip.NetworkProtocolNumber
}
func (st *snatTargetMakerV6) id() targetID {
return targetID{
name: SNATTargetName,
networkProtocol: st.NetworkProtocol,
revision: 1,
}
}
func (*snatTargetMakerV6) marshal(target target) []byte {
st := target.(*snatTarget)
nt := nfNATTarget{
Target: linux.XTEntryTarget{
TargetSize: nfNATMarshalledSize,
},
Range: linux.NFNATRange{
Flags: linux.NF_NAT_RANGE_MAP_IPS | linux.NF_NAT_RANGE_PROTO_SPECIFIED,
},
}
copy(nt.Target.Name[:], SNATTargetName)
copy(nt.Range.MinAddr[:], st.Addr.AsSlice())
copy(nt.Range.MaxAddr[:], st.Addr.AsSlice())
nt.Range.MinProto = htons(st.Port)
nt.Range.MaxProto = nt.Range.MinProto
return marshal.Marshal(&nt)
}
func (*snatTargetMakerV6) unmarshal(buf []byte, filter stack.IPHeaderFilter) (target, *syserr.Error) {
if size := nfNATMarshalledSize; len(buf) < size {
nflog("snatTargetMakerV6: buf has insufficient size (%d) for SNAT V6 target (%d)", len(buf), size)
return nil, syserr.ErrInvalidArgument
}
if p := filter.Protocol; p != header.TCPProtocolNumber && p != header.UDPProtocolNumber {
nflog("snatTargetMakerV6: bad proto %d", p)
return nil, syserr.ErrInvalidArgument
}
var natRange linux.NFNATRange
natRange.UnmarshalUnsafe(buf[linux.SizeOfXTEntryTarget:])
// TODO(gvisor.dev/issue/5697): Support port or address ranges.
if natRange.MinAddr != natRange.MaxAddr {
nflog("snatTargetMakerV6: MinAddr and MaxAddr are different")
return nil, syserr.ErrInvalidArgument
}
if natRange.MinProto != natRange.MaxProto {
nflog("snatTargetMakerV6: MinProto and MaxProto are different")
return nil, syserr.ErrInvalidArgument
}
// TODO(gvisor.dev/issue/5698): Support other NF_NAT_RANGE flags.
if natRange.Flags != linux.NF_NAT_RANGE_MAP_IPS|linux.NF_NAT_RANGE_PROTO_SPECIFIED {
nflog("snatTargetMakerV6: invalid range flags %d", natRange.Flags)
return nil, syserr.ErrInvalidArgument
}
target := snatTarget{
SNATTarget: stack.SNATTarget{
NetworkProtocol: filter.NetworkProtocol(),
Addr: tcpip.AddrFrom16(natRange.MinAddr),
Port: ntohs(natRange.MinProto),
},
}
return &target, nil
}
// translateToStandardTarget translates from the value in a
// linux.XTStandardTarget to an stack.Verdict.
func translateToStandardTarget(val int32, netProto tcpip.NetworkProtocolNumber) (target, *syserr.Error) {
switch val {
case -linux.NF_ACCEPT - 1:
return &acceptTarget{stack.AcceptTarget{
NetworkProtocol: netProto,
}}, nil
case -linux.NF_DROP - 1:
return &dropTarget{stack.DropTarget{
NetworkProtocol: netProto,
}}, nil
case -linux.NF_QUEUE - 1:
nflog("unsupported iptables verdict QUEUE")
return nil, syserr.ErrInvalidArgument
case linux.NF_RETURN:
return &returnTarget{stack.ReturnTarget{
NetworkProtocol: netProto,
}}, nil
default:
nflog("unknown iptables verdict %d", val)
return nil, syserr.ErrInvalidArgument
}
}
// parseTarget parses a target from optVal. optVal should contain only the
// target.
func parseTarget(filter stack.IPHeaderFilter, optVal []byte, ipv6 bool) (stack.Target, *syserr.Error) {
nflog("set entries: parsing target of size %d", len(optVal))
if len(optVal) < linux.SizeOfXTEntryTarget {
nflog("optVal has insufficient size for entry target %d", len(optVal))
return nil, syserr.ErrInvalidArgument
}
var target linux.XTEntryTarget
// Do not advance optVal as targetMake.unmarshal() may unmarshal
// XTEntryTarget again but with some added fields.
target.UnmarshalUnsafe(optVal)
return unmarshalTarget(target, filter, optVal)
}
// JumpTarget implements stack.Target.
type JumpTarget struct {
// Offset is the byte offset of the rule to jump to. It is used for
// marshaling and unmarshaling.
Offset uint32
// RuleNum is the rule to jump to.
RuleNum int
// NetworkProtocol is the network protocol the target is used with.
NetworkProtocol tcpip.NetworkProtocolNumber
}
// ID implements Target.ID.
func (jt *JumpTarget) id() targetID {
return targetID{
networkProtocol: jt.NetworkProtocol,
}
}
// Action implements stack.Target.Action.
func (jt *JumpTarget) Action(stack.PacketBufferPtr, stack.Hook, *stack.Route, stack.AddressableEndpoint) (stack.RuleVerdict, int) {
return stack.RuleJump, jt.RuleNum
}
func ntohs(port uint16) uint16 {
buf := make([]byte, 2)
binary.BigEndian.PutUint16(buf, port)
return hostarch.ByteOrder.Uint16(buf)
}
func htons(port uint16) uint16 {
buf := make([]byte, 2)
hostarch.ByteOrder.PutUint16(buf, port)
return binary.BigEndian.Uint16(buf)
}