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
29extern "C" int system_nosh(const char *command);
30
31
32static 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
48static 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
55static 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
66void 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