90e4063fd2
DAD proxy daemon responsible for forwarding NS/NA between tethered iface and upstream iface. Change-Id: I2e58e10e7fa7dba6a6f63ad03b000549f3afc37e
202 lines
6.8 KiB
C++
202 lines
6.8 KiB
C++
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <errno.h>
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#include <error.h>
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#include <jni.h>
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#include <linux/filter.h>
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#include <nativehelper/JNIHelp.h>
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#include <nativehelper/JNIHelpCompat.h>
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#include <nativehelper/ScopedUtfChars.h>
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#include <net/if.h>
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#include <netinet/ether.h>
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#include <netinet/ip6.h>
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#include <netinet/icmp6.h>
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#include <sys/socket.h>
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#include <stdio.h>
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#define LOG_TAG "TetheringUtils"
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#include <android/log.h>
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namespace android {
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static const uint32_t kIPv6NextHeaderOffset = offsetof(ip6_hdr, ip6_nxt);
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static const uint32_t kIPv6PayloadStart = sizeof(ip6_hdr);
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static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type);
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static void android_net_util_setupIcmpFilter(JNIEnv *env, jobject javaFd, uint32_t type) {
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sock_filter filter_code[] = {
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// Check header is ICMPv6.
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BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeaderOffset),
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BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3),
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// Check ICMPv6 type.
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BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset),
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BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, type, 0, 1),
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// Accept or reject.
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BPF_STMT(BPF_RET | BPF_K, 0xffff),
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BPF_STMT(BPF_RET | BPF_K, 0)
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};
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const sock_fprog filter = {
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sizeof(filter_code) / sizeof(filter_code[0]),
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filter_code,
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};
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(SO_ATTACH_FILTER): %s", strerror(errno));
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}
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}
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static void android_net_util_setupNaSocket(JNIEnv *env, jobject clazz, jobject javaFd)
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{
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android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_ADVERT);
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}
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static void android_net_util_setupNsSocket(JNIEnv *env, jobject clazz, jobject javaFd)
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{
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android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_SOLICIT);
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}
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static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd,
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jint ifIndex)
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{
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static const int kLinkLocalHopLimit = 255;
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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// Set an ICMPv6 filter that only passes Router Solicitations.
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struct icmp6_filter rs_only;
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ICMP6_FILTER_SETBLOCKALL(&rs_only);
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ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &rs_only);
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socklen_t len = sizeof(rs_only);
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if (setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &rs_only, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(ICMP6_FILTER): %s", strerror(errno));
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return;
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}
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// Most/all of the rest of these options can be set via Java code, but
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// because we're here on account of setting an icmp6_filter go ahead
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// and do it all natively for now.
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// Set the multicast hoplimit to 255 (link-local only).
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int hops = kLinkLocalHopLimit;
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len = sizeof(hops);
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if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(IPV6_MULTICAST_HOPS): %s", strerror(errno));
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return;
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}
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// Set the unicast hoplimit to 255 (link-local only).
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hops = kLinkLocalHopLimit;
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len = sizeof(hops);
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if (setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hops, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(IPV6_UNICAST_HOPS): %s", strerror(errno));
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return;
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}
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// Explicitly disable multicast loopback.
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int off = 0;
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len = sizeof(off);
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if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(IPV6_MULTICAST_LOOP): %s", strerror(errno));
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return;
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}
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// Specify the IPv6 interface to use for outbound multicast.
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len = sizeof(ifIndex);
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if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &ifIndex, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(IPV6_MULTICAST_IF): %s", strerror(errno));
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return;
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}
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// Additional options to be considered:
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// - IPV6_TCLASS
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// - IPV6_RECVPKTINFO
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// - IPV6_RECVHOPLIMIT
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// Bind to [::].
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const struct sockaddr_in6 sin6 = {
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.sin6_family = AF_INET6,
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.sin6_port = 0,
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.sin6_flowinfo = 0,
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.sin6_addr = IN6ADDR_ANY_INIT,
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.sin6_scope_id = 0,
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};
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auto sa = reinterpret_cast<const struct sockaddr *>(&sin6);
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len = sizeof(sin6);
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if (bind(fd, sa, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"bind(IN6ADDR_ANY): %s", strerror(errno));
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return;
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}
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// Join the all-routers multicast group, ff02::2%index.
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struct ipv6_mreq all_rtrs = {
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.ipv6mr_multiaddr = {{{0xff,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2}}},
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.ipv6mr_interface = ifIndex,
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};
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len = sizeof(all_rtrs);
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if (setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &all_rtrs, len) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(IPV6_JOIN_GROUP): %s", strerror(errno));
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return;
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}
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}
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/*
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* JNI registration.
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*/
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static const JNINativeMethod gMethods[] = {
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/* name, signature, funcPtr */
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{ "setupNaSocket", "(Ljava/io/FileDescriptor;)V",
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(void*) android_net_util_setupNaSocket },
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{ "setupNsSocket", "(Ljava/io/FileDescriptor;)V",
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(void*) android_net_util_setupNsSocket },
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{ "setupRaSocket", "(Ljava/io/FileDescriptor;I)V",
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(void*) android_net_util_setupRaSocket },
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};
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int register_android_net_util_TetheringUtils(JNIEnv* env) {
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return jniRegisterNativeMethods(env,
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"android/net/util/TetheringUtils",
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gMethods, NELEM(gMethods));
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}
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extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
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JNIEnv *env;
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if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
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__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, "ERROR: GetEnv failed");
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return JNI_ERR;
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}
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if (register_android_net_util_TetheringUtils(env) < 0) {
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return JNI_ERR;
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}
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return JNI_VERSION_1_6;
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}
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}; // namespace android
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