From 1a1cb0e914491ac64743e311c9ca1681eb453750 Mon Sep 17 00:00:00 2001 From: Erik Kline Date: Tue, 24 May 2016 20:12:08 +0900 Subject: [PATCH] Basic IPv6 Router Advertisement daemon Bug: 9580643 Change-Id: Iebd4d1f694699ffd4daf7d71e9b9d8f49e9b632f --- core/java/android/net/NetworkUtils.java | 9 ++- core/jni/android_net_NetUtils.cpp | 94 +++++++++++++++++++++++++ 2 files changed, 102 insertions(+), 1 deletion(-) diff --git a/core/java/android/net/NetworkUtils.java b/core/java/android/net/NetworkUtils.java index 141af3d495..35e3065b07 100644 --- a/core/java/android/net/NetworkUtils.java +++ b/core/java/android/net/NetworkUtils.java @@ -45,12 +45,19 @@ public class NetworkUtils { public native static void attachDhcpFilter(FileDescriptor fd) throws SocketException; /** - * Attaches a socket filter that accepts ICMP6 router advertisement packets to the given socket. + * Attaches a socket filter that accepts ICMPv6 router advertisements to the given socket. * @param fd the socket's {@link FileDescriptor}. * @param packetType the hardware address type, one of ARPHRD_*. */ public native static void attachRaFilter(FileDescriptor fd, int packetType) throws SocketException; + /** + * Configures a socket for receiving ICMPv6 router solicitations and sending advertisements. + * @param fd the socket's {@link FileDescriptor}. + * @param ifIndex the interface index. + */ + public native static void setupRaSocket(FileDescriptor fd, int ifIndex) throws SocketException; + /** * Binds the current process to the network designated by {@code netId}. All sockets created * in the future (and not explicitly bound via a bound {@link SocketFactory} (see diff --git a/core/jni/android_net_NetUtils.cpp b/core/jni/android_net_NetUtils.cpp index 23647871df..679e882999 100644 --- a/core/jni/android_net_NetUtils.cpp +++ b/core/jni/android_net_NetUtils.cpp @@ -125,6 +125,99 @@ static void android_net_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject } } +static void android_net_utils_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. + // + // TODO: Consider moving these out to Java. + + // 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(&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; + } +} + static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId) { return (jboolean) !setNetworkForProcess(netId); @@ -173,6 +266,7 @@ static const JNINativeMethod gNetworkUtilMethods[] = { { "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess }, { "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDhcpFilter }, { "attachRaFilter", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_attachRaFilter }, + { "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_setupRaSocket }, }; int register_android_net_NetworkUtils(JNIEnv* env)