Remi NGUYEN VAN | f38a564 | 2019-04-05 04:44:45 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2019, The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #define LOG_TAG "NetworkStackUtils-JNI" |
| 18 | |
| 19 | #include <errno.h> |
| 20 | #include <jni.h> |
| 21 | #include <linux/filter.h> |
| 22 | #include <linux/if_arp.h> |
| 23 | #include <net/if.h> |
| 24 | #include <netinet/ether.h> |
| 25 | #include <netinet/icmp6.h> |
| 26 | #include <netinet/ip.h> |
| 27 | #include <netinet/ip6.h> |
| 28 | #include <netinet/udp.h> |
| 29 | #include <stdlib.h> |
| 30 | |
| 31 | #include <string> |
| 32 | |
| 33 | #include <nativehelper/JNIHelp.h> |
Lorenzo Colitti | eb2269e | 2019-05-01 11:54:33 +0900 | [diff] [blame] | 34 | #include <android/log.h> |
Remi NGUYEN VAN | f38a564 | 2019-04-05 04:44:45 -0700 | [diff] [blame] | 35 | |
| 36 | namespace android { |
| 37 | constexpr const char NETWORKSTACKUTILS_PKG_NAME[] = "android/net/util/NetworkStackUtils"; |
| 38 | |
| 39 | static const uint32_t kEtherTypeOffset = offsetof(ether_header, ether_type); |
| 40 | static const uint32_t kEtherHeaderLen = sizeof(ether_header); |
| 41 | static const uint32_t kIPv4Protocol = kEtherHeaderLen + offsetof(iphdr, protocol); |
| 42 | static const uint32_t kIPv4FlagsOffset = kEtherHeaderLen + offsetof(iphdr, frag_off); |
| 43 | static const uint32_t kIPv6NextHeader = kEtherHeaderLen + offsetof(ip6_hdr, ip6_nxt); |
| 44 | static const uint32_t kIPv6PayloadStart = kEtherHeaderLen + sizeof(ip6_hdr); |
| 45 | static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type); |
| 46 | static const uint32_t kUDPSrcPortIndirectOffset = kEtherHeaderLen + offsetof(udphdr, source); |
| 47 | static const uint32_t kUDPDstPortIndirectOffset = kEtherHeaderLen + offsetof(udphdr, dest); |
| 48 | static const uint16_t kDhcpClientPort = 68; |
| 49 | |
| 50 | static bool checkLenAndCopy(JNIEnv* env, const jbyteArray& addr, int len, void* dst) { |
| 51 | if (env->GetArrayLength(addr) != len) { |
| 52 | return false; |
| 53 | } |
| 54 | env->GetByteArrayRegion(addr, 0, len, reinterpret_cast<jbyte*>(dst)); |
| 55 | return true; |
| 56 | } |
| 57 | |
| 58 | static void network_stack_utils_addArpEntry(JNIEnv *env, jobject thiz, jbyteArray ethAddr, |
| 59 | jbyteArray ipv4Addr, jstring ifname, jobject javaFd) { |
| 60 | arpreq req = {}; |
| 61 | sockaddr_in& netAddrStruct = *reinterpret_cast<sockaddr_in*>(&req.arp_pa); |
| 62 | sockaddr& ethAddrStruct = req.arp_ha; |
| 63 | |
| 64 | ethAddrStruct.sa_family = ARPHRD_ETHER; |
| 65 | if (!checkLenAndCopy(env, ethAddr, ETH_ALEN, ethAddrStruct.sa_data)) { |
| 66 | jniThrowException(env, "java/io/IOException", "Invalid ethAddr length"); |
| 67 | return; |
| 68 | } |
| 69 | |
| 70 | netAddrStruct.sin_family = AF_INET; |
| 71 | if (!checkLenAndCopy(env, ipv4Addr, sizeof(in_addr), &netAddrStruct.sin_addr)) { |
| 72 | jniThrowException(env, "java/io/IOException", "Invalid ipv4Addr length"); |
| 73 | return; |
| 74 | } |
| 75 | |
| 76 | int ifLen = env->GetStringLength(ifname); |
| 77 | // IFNAMSIZ includes the terminating NULL character |
| 78 | if (ifLen >= IFNAMSIZ) { |
| 79 | jniThrowException(env, "java/io/IOException", "ifname too long"); |
| 80 | return; |
| 81 | } |
| 82 | env->GetStringUTFRegion(ifname, 0, ifLen, req.arp_dev); |
| 83 | |
| 84 | req.arp_flags = ATF_COM; // Completed entry (ha valid) |
| 85 | int fd = jniGetFDFromFileDescriptor(env, javaFd); |
| 86 | if (fd < 0) { |
| 87 | jniThrowExceptionFmt(env, "java/io/IOException", "Invalid file descriptor"); |
| 88 | return; |
| 89 | } |
| 90 | // See also: man 7 arp |
| 91 | if (ioctl(fd, SIOCSARP, &req)) { |
| 92 | jniThrowExceptionFmt(env, "java/io/IOException", "ioctl error: %s", strerror(errno)); |
| 93 | return; |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | static void network_stack_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd) { |
| 98 | static sock_filter filter_code[] = { |
| 99 | // Check the protocol is UDP. |
| 100 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv4Protocol), |
| 101 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 6), |
| 102 | |
| 103 | // Check this is not a fragment. |
| 104 | BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kIPv4FlagsOffset), |
| 105 | BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, IP_OFFMASK, 4, 0), |
| 106 | |
| 107 | // Get the IP header length. |
| 108 | BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, kEtherHeaderLen), |
| 109 | |
| 110 | // Check the destination port. |
| 111 | BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPDstPortIndirectOffset), |
| 112 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 0, 1), |
| 113 | |
| 114 | // Accept or reject. |
| 115 | BPF_STMT(BPF_RET | BPF_K, 0xffff), |
| 116 | BPF_STMT(BPF_RET | BPF_K, 0) |
| 117 | }; |
| 118 | static const sock_fprog filter = { |
| 119 | sizeof(filter_code) / sizeof(filter_code[0]), |
| 120 | filter_code, |
| 121 | }; |
| 122 | |
| 123 | int fd = jniGetFDFromFileDescriptor(env, javaFd); |
| 124 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { |
| 125 | jniThrowExceptionFmt(env, "java/net/SocketException", |
| 126 | "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno)); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | static void network_stack_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject javaFd, |
| 131 | jint hardwareAddressType) { |
| 132 | if (hardwareAddressType != ARPHRD_ETHER) { |
| 133 | jniThrowExceptionFmt(env, "java/net/SocketException", |
| 134 | "attachRaFilter only supports ARPHRD_ETHER"); |
| 135 | return; |
| 136 | } |
| 137 | |
| 138 | static sock_filter filter_code[] = { |
| 139 | // Check IPv6 Next Header is ICMPv6. |
| 140 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeader), |
| 141 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3), |
| 142 | |
| 143 | // Check ICMPv6 type is Router Advertisement. |
| 144 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset), |
| 145 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_ROUTER_ADVERT, 0, 1), |
| 146 | |
| 147 | // Accept or reject. |
| 148 | BPF_STMT(BPF_RET | BPF_K, 0xffff), |
| 149 | BPF_STMT(BPF_RET | BPF_K, 0) |
| 150 | }; |
| 151 | static const sock_fprog filter = { |
| 152 | sizeof(filter_code) / sizeof(filter_code[0]), |
| 153 | filter_code, |
| 154 | }; |
| 155 | |
| 156 | int fd = jniGetFDFromFileDescriptor(env, javaFd); |
| 157 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { |
| 158 | jniThrowExceptionFmt(env, "java/net/SocketException", |
| 159 | "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno)); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | // TODO: Move all this filter code into libnetutils. |
| 164 | static void network_stack_utils_attachControlPacketFilter( |
| 165 | JNIEnv *env, jobject clazz, jobject javaFd, jint hardwareAddressType) { |
| 166 | if (hardwareAddressType != ARPHRD_ETHER) { |
| 167 | jniThrowExceptionFmt(env, "java/net/SocketException", |
| 168 | "attachControlPacketFilter only supports ARPHRD_ETHER"); |
| 169 | return; |
| 170 | } |
| 171 | |
| 172 | // Capture all: |
| 173 | // - ARPs |
| 174 | // - DHCPv4 packets |
| 175 | // - Router Advertisements & Solicitations |
| 176 | // - Neighbor Advertisements & Solicitations |
| 177 | // |
| 178 | // tcpdump: |
| 179 | // arp or |
| 180 | // '(ip and udp port 68)' or |
| 181 | // '(icmp6 and ip6[40] >= 133 and ip6[40] <= 136)' |
| 182 | static sock_filter filter_code[] = { |
| 183 | // Load the link layer next payload field. |
| 184 | BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kEtherTypeOffset), |
| 185 | |
| 186 | // Accept all ARP. |
| 187 | // TODO: Figure out how to better filter ARPs on noisy networks. |
| 188 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_ARP, 16, 0), |
| 189 | |
| 190 | // If IPv4: |
| 191 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_IP, 0, 9), |
| 192 | |
| 193 | // Check the protocol is UDP. |
| 194 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv4Protocol), |
| 195 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 14), |
| 196 | |
| 197 | // Check this is not a fragment. |
| 198 | BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kIPv4FlagsOffset), |
| 199 | BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, IP_OFFMASK, 12, 0), |
| 200 | |
| 201 | // Get the IP header length. |
| 202 | BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, kEtherHeaderLen), |
| 203 | |
| 204 | // Check the source port. |
| 205 | BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPSrcPortIndirectOffset), |
| 206 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 8, 0), |
| 207 | |
| 208 | // Check the destination port. |
| 209 | BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPDstPortIndirectOffset), |
| 210 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 6, 7), |
| 211 | |
| 212 | // IPv6 ... |
| 213 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_IPV6, 0, 6), |
| 214 | // ... check IPv6 Next Header is ICMPv6 (ignore fragments), ... |
| 215 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeader), |
| 216 | BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 4), |
| 217 | // ... and check the ICMPv6 type is one of RS/RA/NS/NA. |
| 218 | BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset), |
| 219 | BPF_JUMP(BPF_JMP | BPF_JGE | BPF_K, ND_ROUTER_SOLICIT, 0, 2), |
| 220 | BPF_JUMP(BPF_JMP | BPF_JGT | BPF_K, ND_NEIGHBOR_ADVERT, 1, 0), |
| 221 | |
| 222 | // Accept or reject. |
| 223 | BPF_STMT(BPF_RET | BPF_K, 0xffff), |
| 224 | BPF_STMT(BPF_RET | BPF_K, 0) |
| 225 | }; |
| 226 | static const sock_fprog filter = { |
| 227 | sizeof(filter_code) / sizeof(filter_code[0]), |
| 228 | filter_code, |
| 229 | }; |
| 230 | |
| 231 | int fd = jniGetFDFromFileDescriptor(env, javaFd); |
| 232 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) { |
| 233 | jniThrowExceptionFmt(env, "java/net/SocketException", |
| 234 | "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno)); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * JNI registration. |
| 240 | */ |
| 241 | static const JNINativeMethod gNetworkStackUtilsMethods[] = { |
| 242 | /* name, signature, funcPtr */ |
| 243 | { "addArpEntry", "([B[BLjava/lang/String;Ljava/io/FileDescriptor;)V", (void*) network_stack_utils_addArpEntry }, |
| 244 | { "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) network_stack_utils_attachDhcpFilter }, |
| 245 | { "attachRaFilter", "(Ljava/io/FileDescriptor;I)V", (void*) network_stack_utils_attachRaFilter }, |
| 246 | { "attachControlPacketFilter", "(Ljava/io/FileDescriptor;I)V", (void*) network_stack_utils_attachControlPacketFilter }, |
| 247 | }; |
| 248 | |
| 249 | extern "C" jint JNI_OnLoad(JavaVM* vm, void*) { |
| 250 | JNIEnv *env; |
| 251 | if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) { |
Lorenzo Colitti | eb2269e | 2019-05-01 11:54:33 +0900 | [diff] [blame] | 252 | __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, "ERROR: GetEnv failed"); |
Remi NGUYEN VAN | f38a564 | 2019-04-05 04:44:45 -0700 | [diff] [blame] | 253 | return JNI_ERR; |
| 254 | } |
| 255 | |
| 256 | if (jniRegisterNativeMethods(env, NETWORKSTACKUTILS_PKG_NAME, |
| 257 | gNetworkStackUtilsMethods, NELEM(gNetworkStackUtilsMethods)) < 0) { |
| 258 | return JNI_ERR; |
| 259 | } |
| 260 | |
| 261 | return JNI_VERSION_1_6; |
| 262 | |
| 263 | } |
Lorenzo Colitti | eb2269e | 2019-05-01 11:54:33 +0900 | [diff] [blame] | 264 | }; // namespace android |