1 /*
2  * Copyright 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  * NatControllerTest.cpp - unit tests for NatController.cpp
17  */
18 
19 #include <string>
20 #include <vector>
21 
22 #include <fcntl.h>
23 #include <unistd.h>
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 
27 #include <gtest/gtest.h>
28 
29 #include <android-base/stringprintf.h>
30 #include <android-base/strings.h>
31 
32 #include "NatController.h"
33 #include "IptablesBaseTest.h"
34 
35 using android::base::StringPrintf;
36 
37 class NatControllerTest : public IptablesBaseTest {
38 public:
NatControllerTest()39     NatControllerTest() {
40         NatController::execFunction = fake_android_fork_exec;
41         NatController::iptablesRestoreFunction = fakeExecIptablesRestore;
42     }
43 
44 protected:
45     NatController mNatCtrl;
46 
setDefaults()47     int setDefaults() {
48         return mNatCtrl.setDefaults();
49     }
50 
51     const ExpectedIptablesCommands FLUSH_COMMANDS = {
52         { V4,   "*filter\n"
53                 ":natctrl_FORWARD -\n"
54                 "-A natctrl_FORWARD -j DROP\n"
55                 "COMMIT\n"
56                 "*nat\n"
57                 ":natctrl_nat_POSTROUTING -\n"
58                 "COMMIT\n" },
59         { V6,   "*filter\n"
60                 ":natctrl_FORWARD -\n"
61                 "COMMIT\n"
62                 "*raw\n"
63                 ":natctrl_raw_PREROUTING -\n"
64                 "COMMIT\n" },
65     };
66 
67     const ExpectedIptablesCommands SETUP_COMMANDS = {
68         { V4,   "*filter\n"
69                 ":natctrl_FORWARD -\n"
70                 "-A natctrl_FORWARD -j DROP\n"
71                 "COMMIT\n"
72                 "*nat\n"
73                 ":natctrl_nat_POSTROUTING -\n"
74                 "COMMIT\n" },
75         { V6,   "*filter\n"
76                 ":natctrl_FORWARD -\n"
77                 "COMMIT\n"
78                 "*raw\n"
79                 ":natctrl_raw_PREROUTING -\n"
80                 "COMMIT\n" },
81         { V4,   "*mangle\n"
82                 "-A natctrl_mangle_FORWARD -p tcp --tcp-flags SYN SYN "
83                     "-j TCPMSS --clamp-mss-to-pmtu\n"
84                 "COMMIT\n" },
85         { V4V6, "*filter\n"
86                 ":natctrl_tether_counters -\n"
87                 "COMMIT\n" },
88     };
89 
90     const ExpectedIptablesCommands TWIDDLE_COMMANDS = {
91         { V4, "-D natctrl_FORWARD -j DROP" },
92         { V4, "-A natctrl_FORWARD -j DROP" },
93     };
94 
firstNatCommands(const char * extIf)95     ExpectedIptablesCommands firstNatCommands(const char *extIf) {
96         return {
97             { V4, StringPrintf("-t nat -A natctrl_nat_POSTROUTING -o %s -j MASQUERADE", extIf) },
98             { V6, "-A natctrl_FORWARD -g natctrl_tether_counters" },
99         };
100     }
101 
startNatCommands(const char * intIf,const char * extIf)102     ExpectedIptablesCommands startNatCommands(const char *intIf, const char *extIf) {
103         return {
104             { V4,   StringPrintf("-A natctrl_FORWARD -i %s -o %s -m state --state"
105                                  " ESTABLISHED,RELATED -g natctrl_tether_counters", extIf, intIf) },
106             { V4,   StringPrintf("-A natctrl_FORWARD -i %s -o %s -m state --state INVALID -j DROP",
107                                  intIf, extIf) },
108             { V4,   StringPrintf("-A natctrl_FORWARD -i %s -o %s -g natctrl_tether_counters",
109                                  intIf, extIf) },
110             { V6,   StringPrintf("-t raw -A natctrl_raw_PREROUTING -i %s -m rpfilter --invert"
111                                  " ! -s fe80::/64 -j DROP", intIf) },
112             { V4V6, StringPrintf("-A natctrl_tether_counters -i %s -o %s -j RETURN",
113                                  intIf, extIf) },
114             { V4V6, StringPrintf("-A natctrl_tether_counters -i %s -o %s -j RETURN",
115                                  extIf, intIf) },
116         };
117     }
118 
stopNatCommands(const char * intIf,const char * extIf)119     ExpectedIptablesCommands stopNatCommands(const char *intIf, const char *extIf) {
120         return {
121             { V4, StringPrintf("-D natctrl_FORWARD -i %s -o %s -m state --state"
122                                " ESTABLISHED,RELATED -g natctrl_tether_counters", extIf, intIf) },
123             { V4, StringPrintf("-D natctrl_FORWARD -i %s -o %s -m state --state INVALID -j DROP",
124                                intIf, extIf) },
125             { V4, StringPrintf("-D natctrl_FORWARD -i %s -o %s -g natctrl_tether_counters",
126                                intIf, extIf) },
127             { V6, StringPrintf("-t raw -D natctrl_raw_PREROUTING -i %s -m rpfilter --invert"
128                                " ! -s fe80::/64 -j DROP", intIf) },
129         };
130     }
131 };
132 
TEST_F(NatControllerTest,TestSetupIptablesHooks)133 TEST_F(NatControllerTest, TestSetupIptablesHooks) {
134     mNatCtrl.setupIptablesHooks();
135     expectIptablesRestoreCommands(SETUP_COMMANDS);
136 }
137 
TEST_F(NatControllerTest,TestSetDefaults)138 TEST_F(NatControllerTest, TestSetDefaults) {
139     setDefaults();
140     expectIptablesRestoreCommands(FLUSH_COMMANDS);
141 }
142 
TEST_F(NatControllerTest,TestAddAndRemoveNat)143 TEST_F(NatControllerTest, TestAddAndRemoveNat) {
144 
145     std::vector<ExpectedIptablesCommands> startFirstNat = {
146         firstNatCommands("rmnet0"),
147         startNatCommands("wlan0", "rmnet0"),
148         TWIDDLE_COMMANDS,
149     };
150     mNatCtrl.enableNat("wlan0", "rmnet0");
151     expectIptablesCommands(startFirstNat);
152 
153     std::vector<ExpectedIptablesCommands> startOtherNat = {
154          startNatCommands("usb0", "rmnet0"),
155          TWIDDLE_COMMANDS,
156     };
157     mNatCtrl.enableNat("usb0", "rmnet0");
158     expectIptablesCommands(startOtherNat);
159 
160     ExpectedIptablesCommands stopOtherNat = stopNatCommands("wlan0", "rmnet0");
161     mNatCtrl.disableNat("wlan0", "rmnet0");
162     expectIptablesCommands(stopOtherNat);
163 
164     ExpectedIptablesCommands stopLastNat = stopNatCommands("usb0", "rmnet0");
165     mNatCtrl.disableNat("usb0", "rmnet0");
166     expectIptablesCommands(stopLastNat);
167     expectIptablesRestoreCommands(FLUSH_COMMANDS);
168 }
169