1 /*
2 * Copyright (C) 2023 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 #define LOG_TAG "jniThreadTun"
18
19 #include <arpa/inet.h>
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <inttypes.h>
23 #include <linux/if_arp.h>
24 #include <linux/if_tun.h>
25 #include <linux/ioctl.h>
26 #include <log/log.h>
27 #include <net/if.h>
28 #include <spawn.h>
29 #include <sys/wait.h>
30 #include <string>
31
32 #include <private/android_filesystem_config.h>
33
34 #include "jni.h"
35 #include "nativehelper/JNIHelp.h"
36 #include "nativehelper/scoped_utf_chars.h"
37
38 namespace android {
com_android_server_thread_TunInterfaceController_createTunInterface(JNIEnv * env,jobject clazz,jstring interfaceName,jint mtu)39 static jint com_android_server_thread_TunInterfaceController_createTunInterface(
40 JNIEnv* env, jobject clazz, jstring interfaceName, jint mtu) {
41 ScopedUtfChars ifName(env, interfaceName);
42
43 int fd = open("/dev/net/tun", O_RDWR | O_NONBLOCK | O_CLOEXEC);
44 if (fd == -1) {
45 jniThrowExceptionFmt(env, "java/io/IOException", "open tun device failed (%s)",
46 strerror(errno));
47 return -1;
48 }
49
50 struct ifreq ifr = {
51 .ifr_flags = IFF_TUN | IFF_NO_PI | static_cast<short>(IFF_TUN_EXCL),
52 };
53 strlcpy(ifr.ifr_name, ifName.c_str(), sizeof(ifr.ifr_name));
54
55 if (ioctl(fd, TUNSETIFF, &ifr, sizeof(ifr)) != 0) {
56 jniThrowExceptionFmt(env, "java/io/IOException", "ioctl(TUNSETIFF) failed (%s)",
57 strerror(errno));
58 close(fd);
59 return -1;
60 }
61
62 int inet6 = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_IP);
63 if (inet6 == -1) {
64 jniThrowExceptionFmt(env, "java/io/IOException", "create inet6 socket failed (%s)",
65 strerror(errno));
66 close(fd);
67 return -1;
68 }
69 ifr.ifr_mtu = mtu;
70 if (ioctl(inet6, SIOCSIFMTU, &ifr) != 0) {
71 jniThrowExceptionFmt(env, "java/io/IOException", "ioctl(SIOCSIFMTU) failed (%s)",
72 strerror(errno));
73 close(fd);
74 close(inet6);
75 return -1;
76 }
77
78 close(inet6);
79 return fd;
80 }
81
com_android_server_thread_TunInterfaceController_setInterfaceUp(JNIEnv * env,jobject clazz,jstring interfaceName,jboolean isUp)82 static void com_android_server_thread_TunInterfaceController_setInterfaceUp(
83 JNIEnv* env, jobject clazz, jstring interfaceName, jboolean isUp) {
84 struct ifreq ifr;
85 ScopedUtfChars ifName(env, interfaceName);
86
87 ifr.ifr_flags = isUp ? IFF_UP : 0;
88 strlcpy(ifr.ifr_name, ifName.c_str(), sizeof(ifr.ifr_name));
89
90 int inet6 = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_IP);
91 if (inet6 == -1) {
92 jniThrowExceptionFmt(env, "java/io/IOException", "create inet6 socket failed (%s)",
93 strerror(errno));
94 }
95
96 if (ioctl(inet6, SIOCSIFFLAGS, &ifr) != 0) {
97 jniThrowExceptionFmt(env, "java/io/IOException", "ioctl(SIOCSIFFLAGS) failed (%s)",
98 strerror(errno));
99 }
100
101 close(inet6);
102 }
103
104 /*
105 * JNI registration.
106 */
107
108 static const JNINativeMethod gMethods[] = {
109 /* name, signature, funcPtr */
nativeCreateTunInterface(Ljava/lang/String;I)110 {"nativeCreateTunInterface",
111 "(Ljava/lang/String;I)I",
112 (void*)com_android_server_thread_TunInterfaceController_createTunInterface},
nativeSetInterfaceUp(Ljava/lang/String;Z)113 {"nativeSetInterfaceUp",
114 "(Ljava/lang/String;Z)V",
115 (void*)com_android_server_thread_TunInterfaceController_setInterfaceUp},
116 };
117
register_com_android_server_thread_TunInterfaceController(JNIEnv * env)118 int register_com_android_server_thread_TunInterfaceController(JNIEnv* env) {
119 return jniRegisterNativeMethods(env, "com/android/server/thread/TunInterfaceController",
120 gMethods, NELEM(gMethods));
121 }
122
123 }; // namespace android
124