ClatdController.cpp revision ac7fefcf3d90cf856b0f1664207d056ed1dd4725 
1/*
2 * Copyright (C) 2008 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#include <map>
17#include <string>
18
19#include <unistd.h>
20#include <errno.h>
21#include <sys/types.h>
22#include <sys/wait.h>
23
24#define LOG_TAG "ClatdController"
25#include <cutils/log.h>
26
27#include <resolv_netid.h>
28
29#include "NetdConstants.h"
30#include "ClatdController.h"
31#include "Fwmark.h"
32#include "NetdConstants.h"
33#include "NetworkController.h"
34
35static const char* kClatdPath = "/system/bin/clatd";
36
37ClatdController::ClatdController(NetworkController* controller)
38        : mNetCtrl(controller) {
39}
40
41ClatdController::~ClatdController() {
42}
43
44// Returns the PID of the clatd running on interface |interface|, or 0 if clatd is not running on
45// |interface|.
46pid_t ClatdController::getClatdPid(char* interface) {
47    auto it = mClatdPids.find(interface);
48    return (it == mClatdPids.end() ? 0 : it->second);
49}
50
51int ClatdController::startClatd(char* interface) {
52    pid_t pid = getClatdPid(interface);
53
54    if (pid != 0) {
55        ALOGE("clatd pid=%d already started on %s", pid, interface);
56        errno = EBUSY;
57        return -1;
58    }
59
60    ALOGD("starting clatd on %s", interface);
61
62    std::string progname("clatd-");
63    progname += interface;
64
65    if ((pid = fork()) < 0) {
66        ALOGE("fork failed (%s)", strerror(errno));
67        return -1;
68    }
69
70    if (!pid) {
71        // Pass in the interface, a netid to use for DNS lookups, and a fwmark for outgoing packets.
72        unsigned netId = mNetCtrl->getNetworkForInterface(interface);
73        if (netId == NETID_UNSET) {
74            ALOGE("interface %s not assigned to any netId", interface);
75            errno = ENODEV;
76            return -1;
77        }
78
79        char netIdString[UINT32_STRLEN];
80        snprintf(netIdString, sizeof(netIdString), "%u", netId);
81
82        Fwmark fwmark;
83        fwmark.netId = netId;
84        fwmark.explicitlySelected = true;
85        fwmark.protectedFromVpn = true;
86        fwmark.permission = PERMISSION_SYSTEM;
87
88        char fwmarkString[UINT32_HEX_STRLEN];
89        snprintf(fwmarkString, sizeof(fwmarkString), "0x%x", fwmark.intValue);
90
91        char *args[] = {
92            (char *) progname.c_str(),
93            (char *) "-i",
94            interface,
95            (char *) "-n",
96            netIdString,
97            (char *) "-m",
98            fwmarkString,
99            NULL
100        };
101
102        if (execv(kClatdPath, args)) {
103            ALOGE("execv failed (%s)", strerror(errno));
104            return -1;
105        }
106        ALOGE("Should never get here!");
107        _exit(0);
108    } else {
109        mClatdPids[interface] = pid;
110        ALOGD("clatd started on %s", interface);
111    }
112
113    return 0;
114}
115
116int ClatdController::stopClatd(char* interface) {
117    pid_t pid = getClatdPid(interface);
118
119    if (pid == 0) {
120        ALOGE("clatd already stopped");
121        return -1;
122    }
123
124    ALOGD("Stopping clatd pid=%d on %s", pid, interface);
125
126    kill(pid, SIGTERM);
127    waitpid(pid, NULL, 0);
128    mClatdPids.erase(interface);
129
130    ALOGD("clatd on %s stopped", interface);
131
132    return 0;
133}
134
135bool ClatdController::isClatdStarted(char* interface) {
136    pid_t waitpid_status;
137    pid_t pid = getClatdPid(interface);
138    if (pid == 0) {
139        return false;
140    }
141    waitpid_status = waitpid(pid, NULL, WNOHANG);
142    if (waitpid_status != 0) {
143        mClatdPids.erase(interface);  // child exited, don't call waitpid on it again
144    }
145    return waitpid_status == 0; // 0 while child is running
146}
147