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
|
// 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 tundev implements the /dev/net/tun device.
package tundev
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs"
"gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/tcpip/link/tun"
"gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
const (
netTunDevMajor = 10
netTunDevMinor = 200
)
// tunDevice implements vfs.Device for /dev/net/tun.
//
// +stateify savable
type tunDevice struct{}
// Open implements vfs.Device.Open.
func (tunDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
fd := &tunFD{}
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
UseDentryMetadata: true,
}); err != nil {
return nil, err
}
return &fd.vfsfd, nil
}
// tunFD implements vfs.FileDescriptionImpl for /dev/net/tun.
//
// +stateify savable
type tunFD struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
vfs.DentryMetadataFileDescriptionImpl
vfs.NoLockFD
device tun.Device
}
// Ioctl implements vfs.FileDescriptionImpl.Ioctl.
func (fd *tunFD) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) {
request := args[1].Uint()
data := args[2].Pointer()
t := kernel.TaskFromContext(ctx)
if t == nil {
panic("Ioctl should be called from a task context")
}
switch request {
case linux.TUNSETIFF:
if !t.HasCapability(linux.CAP_NET_ADMIN) {
return 0, syserror.EPERM
}
stack, ok := t.NetworkContext().(*netstack.Stack)
if !ok {
return 0, linuxerr.EINVAL
}
var req linux.IFReq
if _, err := req.CopyIn(t, data); err != nil {
return 0, err
}
// Validate flags.
flags, err := netstack.LinuxToTUNFlags(hostarch.ByteOrder.Uint16(req.Data[:]))
if err != nil {
return 0, err
}
return 0, fd.device.SetIff(stack.Stack, req.Name(), flags)
case linux.TUNGETIFF:
var req linux.IFReq
copy(req.IFName[:], fd.device.Name())
hostarch.ByteOrder.PutUint16(req.Data[:], netstack.TUNFlagsToLinux(fd.device.Flags()))
_, err := req.CopyOut(t, data)
return 0, err
default:
return 0, syserror.ENOTTY
}
}
// Release implements vfs.FileDescriptionImpl.Release.
func (fd *tunFD) Release(ctx context.Context) {
fd.device.Release(ctx)
}
// PRead implements vfs.FileDescriptionImpl.PRead.
func (fd *tunFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
return fd.Read(ctx, dst, opts)
}
// Read implements vfs.FileDescriptionImpl.Read.
func (fd *tunFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
data, err := fd.device.Read()
if err != nil {
return 0, err
}
n, err := dst.CopyOut(ctx, data)
if n > 0 && n < len(data) {
// Not an error for partial copying. Packet truncated.
err = nil
}
return int64(n), err
}
// PWrite implements vfs.FileDescriptionImpl.PWrite.
func (fd *tunFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
return fd.Write(ctx, src, opts)
}
// Write implements vfs.FileDescriptionImpl.Write.
func (fd *tunFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
data := make([]byte, src.NumBytes())
if _, err := src.CopyIn(ctx, data); err != nil {
return 0, err
}
return fd.device.Write(data)
}
// Readiness implements watier.Waitable.Readiness.
func (fd *tunFD) Readiness(mask waiter.EventMask) waiter.EventMask {
return fd.device.Readiness(mask)
}
// EventRegister implements watier.Waitable.EventRegister.
func (fd *tunFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
fd.device.EventRegister(e, mask)
}
// EventUnregister implements watier.Waitable.EventUnregister.
func (fd *tunFD) EventUnregister(e *waiter.Entry) {
fd.device.EventUnregister(e)
}
// IsNetTunSupported returns whether /dev/net/tun device is supported for s.
func IsNetTunSupported(s inet.Stack) bool {
_, ok := s.(*netstack.Stack)
return ok
}
// Register registers all devices implemented by this package in vfsObj.
func Register(vfsObj *vfs.VirtualFilesystem) error {
return vfsObj.RegisterDevice(vfs.CharDevice, netTunDevMajor, netTunDevMinor, tunDevice{}, &vfs.RegisterDeviceOptions{})
}
// CreateDevtmpfsFiles creates device special files in dev representing all
// devices implemented by this package.
func CreateDevtmpfsFiles(ctx context.Context, dev *devtmpfs.Accessor) error {
return dev.CreateDeviceFile(ctx, "net/tun", vfs.CharDevice, netTunDevMajor, netTunDevMinor, 0666 /* mode */)
}
|
