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