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
|
/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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 android.net.util;
import android.net.util.IpUtils;
import android.test.suitebuilder.annotation.SmallTest;
import java.nio.ByteBuffer;
import junit.framework.TestCase;
public class IpUtilsTest extends TestCase {
private static final int IPV4_HEADER_LENGTH = 20;
private static final int IPV6_HEADER_LENGTH = 40;
private static final int TCP_HEADER_LENGTH = 20;
private static final int UDP_HEADER_LENGTH = 8;
private static final int IP_CHECKSUM_OFFSET = 10;
private static final int TCP_CHECKSUM_OFFSET = 16;
private static final int UDP_CHECKSUM_OFFSET = 6;
private int getUnsignedByte(ByteBuffer buf, int offset) {
return buf.get(offset) & 0xff;
}
private int getChecksum(ByteBuffer buf, int offset) {
return getUnsignedByte(buf, offset) * 256 + getUnsignedByte(buf, offset + 1);
}
private void assertChecksumEquals(int expected, short actual) {
assertEquals(Integer.toHexString(expected), Integer.toHexString(actual & 0xffff));
}
// Generate test packets using Python code like this::
//
// from scapy import all as scapy
//
// def JavaPacketDefinition(bytes):
// out = " ByteBuffer packet = ByteBuffer.wrap(new byte[] {\n "
// for i in xrange(len(bytes)):
// out += "(byte) 0x%02x" % ord(bytes[i])
// if i < len(bytes) - 1:
// if i % 4 == 3:
// out += ",\n "
// else:
// out += ", "
// out += "\n });"
// return out
//
// packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2") /
// scapy.UDP(sport=12345, dport=7) /
// "hello")
// print JavaPacketDefinition(str(packet))
@SmallTest
public void testIpv6TcpChecksum() throws Exception {
// packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80) /
// scapy.TCP(sport=12345, dport=7,
// seq=1692871236, ack=128376451, flags=16,
// window=32768) /
// "hello, world")
ByteBuffer packet = ByteBuffer.wrap(new byte[] {
(byte) 0x68, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x20, (byte) 0x06, (byte) 0x40,
(byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
(byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
(byte) 0x30, (byte) 0x39, (byte) 0x00, (byte) 0x07,
(byte) 0x64, (byte) 0xe7, (byte) 0x2a, (byte) 0x44,
(byte) 0x07, (byte) 0xa6, (byte) 0xde, (byte) 0x83,
(byte) 0x50, (byte) 0x10, (byte) 0x80, (byte) 0x00,
(byte) 0xee, (byte) 0x71, (byte) 0x00, (byte) 0x00,
(byte) 0x68, (byte) 0x65, (byte) 0x6c, (byte) 0x6c,
(byte) 0x6f, (byte) 0x2c, (byte) 0x20, (byte) 0x77,
(byte) 0x6f, (byte) 0x72, (byte) 0x6c, (byte) 0x64
});
// Check that a valid packet has checksum 0.
int transportLen = packet.limit() - IPV6_HEADER_LENGTH;
assertEquals(0, IpUtils.tcpChecksum(packet, 0, IPV6_HEADER_LENGTH, transportLen));
// Check that we can calculate the checksum from scratch.
int sumOffset = IPV6_HEADER_LENGTH + TCP_CHECKSUM_OFFSET;
int sum = getUnsignedByte(packet, sumOffset) * 256 + getUnsignedByte(packet, sumOffset + 1);
assertEquals(0xee71, sum);
packet.put(sumOffset, (byte) 0);
packet.put(sumOffset + 1, (byte) 0);
assertChecksumEquals(sum, IpUtils.tcpChecksum(packet, 0, IPV6_HEADER_LENGTH, transportLen));
// Check that writing the checksum back into the packet results in a valid packet.
packet.putShort(
sumOffset,
IpUtils.tcpChecksum(packet, 0, IPV6_HEADER_LENGTH, transportLen));
assertEquals(0, IpUtils.tcpChecksum(packet, 0, IPV6_HEADER_LENGTH, transportLen));
}
@SmallTest
public void testIpv4UdpChecksum() {
// packet = (scapy.IP(src="192.0.2.1", dst="192.0.2.2", tos=0x40) /
// scapy.UDP(sport=32012, dport=4500) /
// "\xff")
ByteBuffer packet = ByteBuffer.wrap(new byte[] {
(byte) 0x45, (byte) 0x40, (byte) 0x00, (byte) 0x1d,
(byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00,
(byte) 0x40, (byte) 0x11, (byte) 0xf6, (byte) 0x8b,
(byte) 0xc0, (byte) 0x00, (byte) 0x02, (byte) 0x01,
(byte) 0xc0, (byte) 0x00, (byte) 0x02, (byte) 0x02,
(byte) 0x7d, (byte) 0x0c, (byte) 0x11, (byte) 0x94,
(byte) 0x00, (byte) 0x09, (byte) 0xee, (byte) 0x36,
(byte) 0xff
});
// Check that a valid packet has IP checksum 0 and UDP checksum 0xffff (0 is not a valid
// UDP checksum, so the udpChecksum rewrites 0 to 0xffff).
assertEquals(0, IpUtils.ipChecksum(packet, 0));
assertEquals((short) 0xffff, IpUtils.udpChecksum(packet, 0, IPV4_HEADER_LENGTH));
// Check that we can calculate the checksums from scratch.
final int ipSumOffset = IP_CHECKSUM_OFFSET;
final int ipSum = getChecksum(packet, ipSumOffset);
assertEquals(0xf68b, ipSum);
packet.put(ipSumOffset, (byte) 0);
packet.put(ipSumOffset + 1, (byte) 0);
assertChecksumEquals(ipSum, IpUtils.ipChecksum(packet, 0));
final int udpSumOffset = IPV4_HEADER_LENGTH + UDP_CHECKSUM_OFFSET;
final int udpSum = getChecksum(packet, udpSumOffset);
assertEquals(0xee36, udpSum);
packet.put(udpSumOffset, (byte) 0);
packet.put(udpSumOffset + 1, (byte) 0);
assertChecksumEquals(udpSum, IpUtils.udpChecksum(packet, 0, IPV4_HEADER_LENGTH));
// Check that writing the checksums back into the packet results in a valid packet.
packet.putShort(ipSumOffset, IpUtils.ipChecksum(packet, 0));
packet.putShort(udpSumOffset, IpUtils.udpChecksum(packet, 0, IPV4_HEADER_LENGTH));
assertEquals(0, IpUtils.ipChecksum(packet, 0));
assertEquals((short) 0xffff, IpUtils.udpChecksum(packet, 0, IPV4_HEADER_LENGTH));
}
}
|
