1 /*
2 * Copyright (C) 2012 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
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <sys/types.h>
20 #include <sys/wait.h>
21 #include <errno.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #define LOG_TAG "OemIptablesHook"
26 #include <cutils/log.h>
27 #include "NetdConstants.h"
28
29 extern "C" int system_nosh(const char *command);
30
31
runIptablesCmd(const char * cmd)32 static int runIptablesCmd(const char *cmd) {
33 char *buffer;
34 size_t len = strnlen(cmd, 255);
35 int res;
36
37 if (len == 255) {
38 ALOGE("command too long");
39 return -1;
40 }
41
42 asprintf(&buffer, "%s %s", IPTABLES_PATH, cmd);
43 res = system_nosh(buffer);
44 free(buffer);
45 return res;
46 }
47
oemCleanupHooks()48 static bool oemCleanupHooks() {
49 runIptablesCmd("-F oem_out");
50 runIptablesCmd("-F oem_fwd");
51 runIptablesCmd("-t nat -F oem_nat_pre");
52 return true;
53 }
54
oemInitChains()55 static bool oemInitChains() {
56 int ret = system(OEM_SCRIPT_PATH);
57 if ((-1 == ret) || (0 != WEXITSTATUS(ret))) {
58 ALOGE("%s failed: %s", OEM_SCRIPT_PATH, strerror(errno));
59 oemCleanupHooks();
60 return false;
61 }
62 return true;
63 }
64
65
setupOemIptablesHook()66 void setupOemIptablesHook() {
67 if (0 == access(OEM_SCRIPT_PATH, R_OK | X_OK)) {
68 // The call to oemCleanupHooks() is superfluous when done on bootup,
69 // but is needed for the case where netd has crashed/stopped and is
70 // restarted.
71 if (oemCleanupHooks() && oemInitChains()) {
72 ALOGI("OEM iptable hook installed.");
73 }
74 }
75 }
76