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
35 static const char* kClatdPath = "/system/bin/clatd";
36
ClatdController(NetworkController * controller)37 ClatdController::ClatdController(NetworkController* controller)
38 : mNetCtrl(controller) {
39 }
40
~ClatdController()41 ClatdController::~ClatdController() {
42 }
43
44 // Returns the PID of the clatd running on interface |interface|, or 0 if clatd is not running on
45 // |interface|.
getClatdPid(char * interface)46 pid_t ClatdController::getClatdPid(char* interface) {
47 auto it = mClatdPids.find(interface);
48 return (it == mClatdPids.end() ? 0 : it->second);
49 }
50
startClatd(char * interface)51 int 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 // Pass in the interface, a netid to use for DNS lookups, and a fwmark for outgoing packets.
61 unsigned netId = mNetCtrl->getNetworkForInterface(interface);
62 if (netId == NETID_UNSET) {
63 ALOGE("interface %s not assigned to any netId", interface);
64 errno = ENODEV;
65 return -1;
66 }
67
68 char netIdString[UINT32_STRLEN];
69 snprintf(netIdString, sizeof(netIdString), "%u", netId);
70
71 Fwmark fwmark;
72 fwmark.netId = netId;
73 fwmark.explicitlySelected = true;
74 fwmark.protectedFromVpn = true;
75 fwmark.permission = PERMISSION_SYSTEM;
76
77 char fwmarkString[UINT32_HEX_STRLEN];
78 snprintf(fwmarkString, sizeof(fwmarkString), "0x%x", fwmark.intValue);
79
80 ALOGD("starting clatd on %s", interface);
81
82 std::string progname("clatd-");
83 progname += interface;
84
85 if ((pid = fork()) < 0) {
86 ALOGE("fork failed (%s)", strerror(errno));
87 return -1;
88 }
89
90 if (!pid) {
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 _exit(1);
105 }
106 ALOGE("Should never get here!");
107 _exit(1);
108 } else {
109 mClatdPids[interface] = pid;
110 ALOGD("clatd started on %s", interface);
111 }
112
113 return 0;
114 }
115
stopClatd(char * interface)116 int 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
isClatdStarted(char * interface)135 bool 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