/* * Copyright 2008, 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. */ #define LOG_TAG "NetUtils" #include "jni.h" #include "JNIHelp.h" #include "NetdClient.h" #include <utils/misc.h> #include <android_runtime/AndroidRuntime.h> #include <utils/Log.h> #include <arpa/inet.h> #include <net/if.h> #include <linux/filter.h> #include <linux/if.h> #include <linux/if_arp.h> #include <linux/if_ether.h> #include <linux/if_packet.h> #include <net/if_ether.h> #include <netinet/icmp6.h> #include <netinet/ip.h> #include <netinet/ip6.h> #include <netinet/udp.h> #include <cutils/properties.h> #include "core_jni_helpers.h" extern "C" { int ifc_enable(const char *ifname); int ifc_disable(const char *ifname); } #define NETUTILS_PKG_NAME "android/net/NetworkUtils" namespace android { static const uint16_t kDhcpClientPort = 68; static void android_net_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd) { uint32_t ip_offset = sizeof(ether_header); uint32_t proto_offset = ip_offset + offsetof(iphdr, protocol); uint32_t flags_offset = ip_offset + offsetof(iphdr, frag_off); uint32_t dport_indirect_offset = ip_offset + offsetof(udphdr, dest); struct sock_filter filter_code[] = { // Check the protocol is UDP. BPF_STMT(BPF_LD | BPF_B | BPF_ABS, proto_offset), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 6), // Check this is not a fragment. BPF_STMT(BPF_LD | BPF_H | BPF_ABS, flags_offset), BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, 0x1fff, 4, 0), // Get the IP header length. BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, ip_offset), // Check the destination port. BPF_STMT(BPF_LD | BPF_H | BPF_IND, dport_indirect_offset), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 0, 1), // Accept or reject. BPF_STMT(BPF_RET | BPF_K, 0xffff), BPF_STMT(BPF_RET | BPF_K, 0) }; struct sock_fprog filter = { sizeof(filter_code) / sizeof(filter_code[0]), filter_code, }; int fd = jniGetFDFromFileDescriptor(env, javaFd); if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { jniThrowExceptionFmt(env, "java/net/SocketException", "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno)); } } static void android_net_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject javaFd, jint hardwareAddressType) { if (hardwareAddressType != ARPHRD_ETHER) { jniThrowExceptionFmt(env, "java/net/SocketException", "attachRaFilter only supports ARPHRD_ETHER"); return; } uint32_t ipv6_offset = sizeof(ether_header); uint32_t ipv6_next_header_offset = ipv6_offset + offsetof(ip6_hdr, ip6_nxt); uint32_t icmp6_offset = ipv6_offset + sizeof(ip6_hdr); uint32_t icmp6_type_offset = icmp6_offset + offsetof(icmp6_hdr, icmp6_type); struct sock_filter filter_code[] = { // Check IPv6 Next Header is ICMPv6. BPF_STMT(BPF_LD | BPF_B | BPF_ABS, ipv6_next_header_offset), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3), // Check ICMPv6 type is Router Advertisement. BPF_STMT(BPF_LD | BPF_B | BPF_ABS, icmp6_type_offset), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_ROUTER_ADVERT, 0, 1), // Accept or reject. BPF_STMT(BPF_RET | BPF_K, 0xffff), BPF_STMT(BPF_RET | BPF_K, 0) }; struct sock_fprog filter = { sizeof(filter_code) / sizeof(filter_code[0]), filter_code, }; int fd = jniGetFDFromFileDescriptor(env, javaFd); if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { jniThrowExceptionFmt(env, "java/net/SocketException", "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno)); } } 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<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; } } static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId) { return (jboolean) !setNetworkForProcess(netId); } static jint android_net_utils_getBoundNetworkForProcess(JNIEnv *env, jobject thiz) { return getNetworkForProcess(); } static jboolean android_net_utils_bindProcessToNetworkForHostResolution(JNIEnv *env, jobject thiz, jint netId) { return (jboolean) !setNetworkForResolv(netId); } static jint android_net_utils_bindSocketToNetwork(JNIEnv *env, jobject thiz, jint socket, jint netId) { return setNetworkForSocket(netId, socket); } static jboolean android_net_utils_protectFromVpn(JNIEnv *env, jobject thiz, jint socket) { return (jboolean) !protectFromVpn(socket); } static jboolean android_net_utils_queryUserAccess(JNIEnv *env, jobject thiz, jint uid, jint netId) { return (jboolean) !queryUserAccess(uid, netId); } // ---------------------------------------------------------------------------- /* * JNI registration. */ static const JNINativeMethod gNetworkUtilMethods[] = { /* name, signature, funcPtr */ { "bindProcessToNetwork", "(I)Z", (void*) android_net_utils_bindProcessToNetwork }, { "getBoundNetworkForProcess", "()I", (void*) android_net_utils_getBoundNetworkForProcess }, { "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution }, { "bindSocketToNetwork", "(II)I", (void*) android_net_utils_bindSocketToNetwork }, { "protectFromVpn", "(I)Z", (void*)android_net_utils_protectFromVpn }, { "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) { return RegisterMethodsOrDie(env, NETUTILS_PKG_NAME, gNetworkUtilMethods, NELEM(gNetworkUtilMethods)); } }; // namespace android