| /* |
| * 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 <linux/filter.h> |
| #include <nativehelper/JNIHelp.h> |
| #include <nativehelper/ScopedUtfChars.h> |
| #include <netjniutils/netjniutils.h> |
| #include <net/if.h> |
| #include <netinet/ether.h> |
| #include <netinet/ip6.h> |
| #include <netinet/icmp6.h> |
| #include <sys/socket.h> |
| #include <stdio.h> |
| |
| namespace android { |
| |
| static const uint32_t kIPv6NextHeaderOffset = offsetof(ip6_hdr, ip6_nxt); |
| static const uint32_t kIPv6PayloadStart = sizeof(ip6_hdr); |
| static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type); |
| |
| static void throwSocketException(JNIEnv *env, const char* msg, int error) { |
| jniThrowExceptionFmt(env, "java/net/SocketException", "%s: %s", msg, strerror(error)); |
| } |
| |
| static void android_net_util_setupIcmpFilter(JNIEnv *env, jobject javaFd, uint32_t type) { |
| sock_filter filter_code[] = { |
| // Check header is ICMPv6. |
| BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeaderOffset), |
| BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3), |
| |
| // Check ICMPv6 type. |
| BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset), |
| BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, type, 0, 1), |
| |
| // Accept or reject. |
| BPF_STMT(BPF_RET | BPF_K, 0xffff), |
| BPF_STMT(BPF_RET | BPF_K, 0) |
| }; |
| |
| const sock_fprog filter = { |
| sizeof(filter_code) / sizeof(filter_code[0]), |
| filter_code, |
| }; |
| |
| int fd = netjniutils::GetNativeFileDescriptor(env, javaFd); |
| if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { |
| throwSocketException(env, "setsockopt(SO_ATTACH_FILTER)", errno); |
| } |
| } |
| |
| static void android_net_util_setupNaSocket(JNIEnv *env, jobject clazz, jobject javaFd) |
| { |
| android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_ADVERT); |
| } |
| |
| static void android_net_util_setupNsSocket(JNIEnv *env, jobject clazz, jobject javaFd) |
| { |
| android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_SOLICIT); |
| } |
| |
| static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd, |
| jint ifIndex) |
| { |
| static const int kLinkLocalHopLimit = 255; |
| |
| int fd = netjniutils::GetNativeFileDescriptor(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) { |
| throwSocketException(env, "setsockopt(ICMP6_FILTER)", 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) { |
| throwSocketException(env, "setsockopt(IPV6_MULTICAST_HOPS)", 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) { |
| throwSocketException(env, "setsockopt(IPV6_UNICAST_HOPS)", errno); |
| return; |
| } |
| |
| // Explicitly disable multicast loopback. |
| int off = 0; |
| len = sizeof(off); |
| if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, len) != 0) { |
| throwSocketException(env, "setsockopt(IPV6_MULTICAST_LOOP)", 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) { |
| throwSocketException(env, "setsockopt(IPV6_MULTICAST_IF)", 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) { |
| throwSocketException(env, "bind(IN6ADDR_ANY)", 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) { |
| throwSocketException(env, "setsockopt(IPV6_JOIN_GROUP)", errno); |
| return; |
| } |
| } |
| |
| /* |
| * JNI registration. |
| */ |
| static const JNINativeMethod gMethods[] = { |
| /* name, signature, funcPtr */ |
| { "setupNaSocket", "(Ljava/io/FileDescriptor;)V", |
| (void*) android_net_util_setupNaSocket }, |
| { "setupNsSocket", "(Ljava/io/FileDescriptor;)V", |
| (void*) android_net_util_setupNsSocket }, |
| { "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)); |
| } |
| |
| }; // namespace android |