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
|
// 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 testbench
import (
"encoding/binary"
"fmt"
"net"
"testing"
"time"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/hostarch"
)
// Sniffer can sniff raw packets on the wire.
type Sniffer struct {
fd int
}
func htons(x uint16) uint16 {
buf := [2]byte{}
binary.BigEndian.PutUint16(buf[:], x)
return hostarch.ByteOrder.Uint16(buf[:])
}
// NewSniffer creates a Sniffer connected to *device.
func (n *DUTTestNet) NewSniffer(t *testing.T) (Sniffer, error) {
t.Helper()
ifInfo, err := net.InterfaceByName(n.LocalDevName)
if err != nil {
return Sniffer{}, err
}
var haddr [8]byte
copy(haddr[:], ifInfo.HardwareAddr)
sa := unix.SockaddrLinklayer{
Protocol: htons(unix.ETH_P_ALL),
Ifindex: ifInfo.Index,
}
snifferFd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL)))
if err != nil {
return Sniffer{}, err
}
if err := unix.Bind(snifferFd, &sa); err != nil {
return Sniffer{}, err
}
if err := unix.SetsockoptInt(snifferFd, unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, 1); err != nil {
t.Fatalf("can't set sockopt SO_RCVBUFFORCE to 1: %s", err)
}
if err := unix.SetsockoptInt(snifferFd, unix.SOL_SOCKET, unix.SO_RCVBUF, 1e7); err != nil {
t.Fatalf("can't setsockopt SO_RCVBUF to 10M: %s", err)
}
return Sniffer{
fd: snifferFd,
}, nil
}
// maxReadSize should be large enough for the maximum frame size in bytes. If a
// packet too large for the buffer arrives, the test will get a fatal error.
const maxReadSize int = 65536
// Recv tries to read one frame until the timeout is up. If the timeout given
// is 0, then no read attempt will be made.
func (s *Sniffer) Recv(t *testing.T, timeout time.Duration) []byte {
t.Helper()
deadline := time.Now().Add(timeout)
for {
timeout = time.Until(deadline)
if timeout <= 0 {
return nil
}
usec := timeout.Microseconds()
if usec == 0 {
// Timeout is less than a microsecond; set usec to 1 to avoid
// blocking indefinitely.
usec = 1
}
const microsInOne = 1e6
tv := unix.Timeval{
Sec: usec / microsInOne,
Usec: usec % microsInOne,
}
if err := unix.SetsockoptTimeval(s.fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &tv); err != nil {
t.Fatalf("can't setsockopt SO_RCVTIMEO: %s", err)
}
buf := make([]byte, maxReadSize)
nread, _, err := unix.Recvfrom(s.fd, buf, unix.MSG_TRUNC)
if err == unix.EINTR || err == unix.EAGAIN {
// There was a timeout.
continue
}
if err != nil {
t.Fatalf("can't read: %s", err)
}
if nread > maxReadSize {
t.Fatalf("received a truncated frame of %d bytes, want at most %d bytes", nread, maxReadSize)
}
return buf[:nread]
}
}
// Drain drains the Sniffer's socket receive buffer by receiving until there's
// nothing else to receive.
func (s *Sniffer) Drain(t *testing.T) {
t.Helper()
flags, err := unix.FcntlInt(uintptr(s.fd), unix.F_GETFL, 0)
if err != nil {
t.Fatalf("failed to get sniffer socket fd flags: %s", err)
}
nonBlockingFlags := flags | unix.O_NONBLOCK
if _, err := unix.FcntlInt(uintptr(s.fd), unix.F_SETFL, nonBlockingFlags); err != nil {
t.Fatalf("failed to make sniffer socket non-blocking with flags %b: %s", nonBlockingFlags, err)
}
for {
buf := make([]byte, maxReadSize)
_, _, err := unix.Recvfrom(s.fd, buf, unix.MSG_TRUNC)
if err == unix.EINTR || err == unix.EAGAIN || err == unix.EWOULDBLOCK {
break
}
}
if _, err := unix.FcntlInt(uintptr(s.fd), unix.F_SETFL, flags); err != nil {
t.Fatalf("failed to restore sniffer socket fd flags to %b: %s", flags, err)
}
}
// close the socket that Sniffer is using.
func (s *Sniffer) close() error {
if err := unix.Close(s.fd); err != nil {
return fmt.Errorf("can't close sniffer socket: %w", err)
}
s.fd = -1
return nil
}
// Injector can inject raw frames.
type Injector struct {
fd int
}
// NewInjector creates a new injector on *device.
func (n *DUTTestNet) NewInjector(t *testing.T) (Injector, error) {
t.Helper()
ifInfo, err := net.InterfaceByName(n.LocalDevName)
if err != nil {
return Injector{}, err
}
var haddr [8]byte
copy(haddr[:], ifInfo.HardwareAddr)
sa := unix.SockaddrLinklayer{
Protocol: htons(unix.ETH_P_IP),
Ifindex: ifInfo.Index,
Halen: uint8(len(ifInfo.HardwareAddr)),
Addr: haddr,
}
injectFd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL)))
if err != nil {
return Injector{}, err
}
if err := unix.Bind(injectFd, &sa); err != nil {
return Injector{}, err
}
return Injector{
fd: injectFd,
}, nil
}
// Send a raw frame.
func (i *Injector) Send(t *testing.T, b []byte) {
t.Helper()
n, err := unix.Write(i.fd, b)
if err != nil {
t.Fatalf("can't write bytes of len %d: %s", len(b), err)
}
if n != len(b) {
t.Fatalf("got %d bytes written, want %d", n, len(b))
}
}
// close the underlying socket.
func (i *Injector) close() error {
if err := unix.Close(i.fd); err != nil {
return fmt.Errorf("can't close sniffer socket: %w", err)
}
i.fd = -1
return nil
}
|
