/*
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* Copyright 2008, 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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#define LOG_TAG "NetUtils"
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#include <vector>
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#include <arpa/inet.h>
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#include <linux/filter.h>
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#include <linux/if_arp.h>
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#include <linux/tcp.h>
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#include <net/if.h>
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#include <netinet/ether.h>
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#include <netinet/icmp6.h>
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#include <netinet/ip.h>
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#include <netinet/ip6.h>
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#include <netinet/udp.h>
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#include <android_runtime/AndroidRuntime.h>
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#include <cutils/properties.h>
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#include <utils/misc.h>
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#include <utils/Log.h>
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#include <nativehelper/JNIHelp.h>
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#include <nativehelper/ScopedLocalRef.h>
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#include "NetdClient.h"
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#include "core_jni_helpers.h"
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#include "jni.h"
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extern "C" {
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int ifc_enable(const char *ifname);
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int ifc_disable(const char *ifname);
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}
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#define NETUTILS_PKG_NAME "android/net/NetworkUtils"
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namespace android {
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constexpr int MAXPACKETSIZE = 8 * 1024;
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// FrameworkListener limits the size of commands to 4096 bytes.
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constexpr int MAXCMDSIZE = 4096;
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static void throwErrnoException(JNIEnv* env, const char* functionName, int error) {
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ScopedLocalRef<jstring> detailMessage(env, env->NewStringUTF(functionName));
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if (detailMessage.get() == NULL) {
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// Not really much we can do here. We're probably dead in the water,
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// but let's try to stumble on...
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env->ExceptionClear();
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}
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static jclass errnoExceptionClass =
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MakeGlobalRefOrDie(env, FindClassOrDie(env, "android/system/ErrnoException"));
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static jmethodID errnoExceptionCtor =
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GetMethodIDOrDie(env, errnoExceptionClass,
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"<init>", "(Ljava/lang/String;I)V");
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jobject exception = env->NewObject(errnoExceptionClass,
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errnoExceptionCtor,
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detailMessage.get(),
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error);
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env->Throw(reinterpret_cast<jthrowable>(exception));
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}
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static void android_net_utils_attachDropAllBPFFilter(JNIEnv *env, jobject clazz, jobject javaFd)
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{
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struct sock_filter filter_code[] = {
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// Reject all.
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BPF_STMT(BPF_RET | BPF_K, 0)
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};
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struct 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_utils_detachBPFFilter(JNIEnv *env, jobject clazz, jobject javaFd)
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{
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int dummy = 0;
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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if (setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, &dummy, sizeof(dummy)) != 0) {
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jniThrowExceptionFmt(env, "java/net/SocketException",
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"setsockopt(SO_DETACH_FILTER): %s", strerror(errno));
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}
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}
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static void android_net_utils_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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//
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// TODO: Consider moving these out to Java.
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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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static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId)
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{
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return (jboolean) !setNetworkForProcess(netId);
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}
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static jint android_net_utils_getBoundNetworkForProcess(JNIEnv *env, jobject thiz)
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{
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return getNetworkForProcess();
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}
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static jboolean android_net_utils_bindProcessToNetworkForHostResolution(JNIEnv *env, jobject thiz,
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jint netId)
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{
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return (jboolean) !setNetworkForResolv(netId);
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}
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static jint android_net_utils_bindSocketToNetwork(JNIEnv *env, jobject thiz, jint socket,
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jint netId)
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{
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return setNetworkForSocket(netId, socket);
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}
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static jboolean android_net_utils_protectFromVpn(JNIEnv *env, jobject thiz, jint socket)
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{
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return (jboolean) !protectFromVpn(socket);
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}
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static jboolean android_net_utils_queryUserAccess(JNIEnv *env, jobject thiz, jint uid, jint netId)
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{
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return (jboolean) !queryUserAccess(uid, netId);
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}
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static bool checkLenAndCopy(JNIEnv* env, const jbyteArray& addr, int len, void* dst)
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{
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if (env->GetArrayLength(addr) != len) {
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return false;
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}
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env->GetByteArrayRegion(addr, 0, len, reinterpret_cast<jbyte*>(dst));
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return true;
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}
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static jobject android_net_utils_resNetworkQuery(JNIEnv *env, jobject thiz, jint netId,
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jstring dname, jint ns_class, jint ns_type, jint flags) {
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const jsize javaCharsCount = env->GetStringLength(dname);
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const jsize byteCountUTF8 = env->GetStringUTFLength(dname);
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// Only allow dname which could be simply formatted to UTF8.
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// In native layer, res_mkquery would re-format the input char array to packet.
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std::vector<char> queryname(byteCountUTF8 + 1, 0);
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env->GetStringUTFRegion(dname, 0, javaCharsCount, queryname.data());
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int fd = resNetworkQuery(netId, queryname.data(), ns_class, ns_type, flags);
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if (fd < 0) {
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throwErrnoException(env, "resNetworkQuery", -fd);
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return nullptr;
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}
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return jniCreateFileDescriptor(env, fd);
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}
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static jobject android_net_utils_resNetworkSend(JNIEnv *env, jobject thiz, jint netId,
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jbyteArray msg, jint msgLen, jint flags) {
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uint8_t data[MAXCMDSIZE];
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checkLenAndCopy(env, msg, msgLen, data);
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int fd = resNetworkSend(netId, data, msgLen, flags);
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if (fd < 0) {
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throwErrnoException(env, "resNetworkSend", -fd);
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return nullptr;
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}
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return jniCreateFileDescriptor(env, fd);
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}
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static jobject android_net_utils_resNetworkResult(JNIEnv *env, jobject thiz, jobject javaFd) {
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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int rcode;
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std::vector<uint8_t> buf(MAXPACKETSIZE, 0);
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int res = resNetworkResult(fd, &rcode, buf.data(), MAXPACKETSIZE);
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jniSetFileDescriptorOfFD(env, javaFd, -1);
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if (res < 0) {
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throwErrnoException(env, "resNetworkResult", -res);
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return nullptr;
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}
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jbyteArray answer = env->NewByteArray(res);
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if (answer == nullptr) {
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throwErrnoException(env, "resNetworkResult", ENOMEM);
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return nullptr;
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} else {
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env->SetByteArrayRegion(answer, 0, res,
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reinterpret_cast<jbyte*>(buf.data()));
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}
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jclass class_DnsResponse = env->FindClass("android/net/DnsResolver$DnsResponse");
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jmethodID ctor = env->GetMethodID(class_DnsResponse, "<init>", "([BI)V");
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return env->NewObject(class_DnsResponse, ctor, answer, rcode);
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}
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static void android_net_utils_resNetworkCancel(JNIEnv *env, jobject thiz, jobject javaFd) {
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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resNetworkCancel(fd);
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jniSetFileDescriptorOfFD(env, javaFd, -1);
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}
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static jobject android_net_utils_getDnsNetwork(JNIEnv *env, jobject thiz) {
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unsigned dnsNetId = 0;
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if (int res = getNetworkForDns(&dnsNetId) < 0) {
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throwErrnoException(env, "getDnsNetId", -res);
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return nullptr;
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}
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bool privateDnsBypass = dnsNetId & NETID_USE_LOCAL_NAMESERVERS;
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static jclass class_Network = MakeGlobalRefOrDie(
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env, FindClassOrDie(env, "android/net/Network"));
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static jmethodID ctor = env->GetMethodID(class_Network, "<init>", "(IZ)V");
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return env->NewObject(
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class_Network, ctor, dnsNetId & ~NETID_USE_LOCAL_NAMESERVERS, privateDnsBypass);
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}
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static jobject android_net_utils_getTcpRepairWindow(JNIEnv *env, jobject thiz, jobject javaFd) {
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if (javaFd == NULL) {
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jniThrowNullPointerException(env, NULL);
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return NULL;
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}
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int fd = jniGetFDFromFileDescriptor(env, javaFd);
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struct tcp_repair_window trw = {};
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socklen_t size = sizeof(trw);
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// Obtain the parameters of the TCP repair window.
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int rc = getsockopt(fd, IPPROTO_TCP, TCP_REPAIR_WINDOW, &trw, &size);
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if (rc == -1) {
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throwErrnoException(env, "getsockopt : TCP_REPAIR_WINDOW", errno);
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return NULL;
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}
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struct tcp_info tcpinfo = {};
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socklen_t tcpinfo_size = sizeof(tcp_info);
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// Obtain the window scale from the tcp info structure. This contains a scale factor that
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// should be applied to the window size.
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rc = getsockopt(fd, IPPROTO_TCP, TCP_INFO, &tcpinfo, &tcpinfo_size);
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if (rc == -1) {
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throwErrnoException(env, "getsockopt : TCP_INFO", errno);
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return NULL;
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}
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jclass class_TcpRepairWindow = env->FindClass("android/net/TcpRepairWindow");
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jmethodID ctor = env->GetMethodID(class_TcpRepairWindow, "<init>", "(IIIIII)V");
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return env->NewObject(class_TcpRepairWindow, ctor, trw.snd_wl1, trw.snd_wnd, trw.max_window,
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trw.rcv_wnd, trw.rcv_wup, tcpinfo.tcpi_rcv_wscale);
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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 gNetworkUtilMethods[] = {
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/* name, signature, funcPtr */
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{ "bindProcessToNetwork", "(I)Z", (void*) android_net_utils_bindProcessToNetwork },
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{ "getBoundNetworkForProcess", "()I", (void*) android_net_utils_getBoundNetworkForProcess },
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{ "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },
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{ "bindSocketToNetwork", "(II)I", (void*) android_net_utils_bindSocketToNetwork },
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{ "protectFromVpn", "(I)Z", (void*)android_net_utils_protectFromVpn },
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{ "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess },
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{ "attachDropAllBPFFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDropAllBPFFilter },
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{ "detachBPFFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_detachBPFFilter },
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{ "getTcpRepairWindow", "(Ljava/io/FileDescriptor;)Landroid/net/TcpRepairWindow;", (void*) android_net_utils_getTcpRepairWindow },
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{ "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_setupRaSocket },
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{ "resNetworkSend", "(I[BII)Ljava/io/FileDescriptor;", (void*) android_net_utils_resNetworkSend },
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{ "resNetworkQuery", "(ILjava/lang/String;III)Ljava/io/FileDescriptor;", (void*) android_net_utils_resNetworkQuery },
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{ "resNetworkResult", "(Ljava/io/FileDescriptor;)Landroid/net/DnsResolver$DnsResponse;", (void*) android_net_utils_resNetworkResult },
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{ "resNetworkCancel", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_resNetworkCancel },
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{ "getDnsNetwork", "()Landroid/net/Network;", (void*) android_net_utils_getDnsNetwork },
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};
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int register_android_net_NetworkUtils(JNIEnv* env)
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{
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return RegisterMethodsOrDie(env, NETUTILS_PKG_NAME, gNetworkUtilMethods,
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NELEM(gNetworkUtilMethods));
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}
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}; // namespace android
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