1 /* 2 * Copyright 2010, 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 #include "AsynchronousSocketCloseMonitor.h" 18 #include "JNIHelp.h" 19 #include "JniException.h" 20 #include "JniConstants.h" 21 #include "NetFd.h" 22 #include "NetworkUtilities.h" 23 #include "ScopedUtfChars.h" 24 #include "ScopedPrimitiveArray.h" 25 26 #include "jni.h" 27 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <linux/rtnetlink.h> 31 #include <net/if.h> 32 #include <linux/if_ether.h> 33 #include <linux/if_packet.h> 34 #include <arpa/inet.h> 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <poll.h> 38 #include <netinet/ip.h> 39 #include <linux/udp.h> 40 41 union sockunion { 42 sockaddr sa; 43 sockaddr_ll sll; 44 }; 45 46 /* 47 * Creates a socket suitable for raw socket operations. The socket is 48 * bound to the interface specified by the supplied name. The socket 49 * value is placed into the supplied FileDescriptor instance. 50 * 51 * TODO(chesnutt): consider breaking this into pieces: create a 52 * variety of constructors for different socket types, then a generic 53 * setBlocking() method followed by polymorphic bind(). 54 */ 55 static void RawSocket_create(JNIEnv* env, jclass, jobject fileDescriptor, 56 jshort protocolType, jstring interfaceName) 57 { 58 59 ScopedUtfChars ifname(env, interfaceName); 60 if (ifname.c_str() == NULL) { 61 return; 62 } 63 64 sockunion su; 65 memset(&su, 0, sizeof(su)); 66 su.sll.sll_family = PF_PACKET; 67 su.sll.sll_protocol = htons(protocolType); 68 su.sll.sll_ifindex = if_nametoindex(ifname.c_str()); 69 int sock = socket(PF_PACKET, SOCK_DGRAM, htons(protocolType)); 70 71 if (sock == -1) { 72 ALOGE("Can't create socket %s", strerror(errno)); 73 jniThrowSocketException(env, errno); 74 return; 75 } 76 77 jniSetFileDescriptorOfFD(env, fileDescriptor, sock); 78 if (!setBlocking(sock, false)) { 79 ALOGE("Can't set non-blocking mode on socket %s", strerror(errno)); 80 jniThrowSocketException(env, errno); 81 return; 82 } 83 84 int err = bind(sock, &su.sa, sizeof(su)); 85 if (err != 0) { 86 ALOGE("Socket bind error %s", strerror(errno)); 87 jniThrowSocketException(env, errno); 88 return; 89 } 90 } 91 92 /* 93 * Writes the L3 (IP) packet to the raw socket supplied in the 94 * FileDescriptor instance. 95 * 96 * Assumes that the caller has validated the offset & byteCount values. 97 */ 98 static int RawSocket_sendPacket(JNIEnv* env, jclass, jobject fileDescriptor, 99 jstring interfaceName, jshort protocolType, jbyteArray destMac, 100 jbyteArray packet, jint offset, jint byteCount) 101 { 102 NetFd fd(env, fileDescriptor); 103 104 if (fd.isClosed()) { 105 return 0; 106 } 107 108 ScopedUtfChars ifname(env, interfaceName); 109 if (ifname.c_str() == NULL) { 110 return 0; 111 } 112 113 ScopedByteArrayRO byteArray(env, packet); 114 if (byteArray.get() == NULL) { 115 return 0; 116 } 117 118 ScopedByteArrayRO mac(env, destMac); 119 if (mac.get() == NULL) { 120 return 0; 121 } 122 123 sockunion su; 124 memset(&su, 0, sizeof(su)); 125 su.sll.sll_hatype = htons(1); // ARPHRD_ETHER 126 su.sll.sll_halen = mac.size(); 127 memcpy(&su.sll.sll_addr, mac.get(), mac.size()); 128 su.sll.sll_family = AF_PACKET; 129 su.sll.sll_protocol = htons(protocolType); 130 su.sll.sll_ifindex = if_nametoindex(ifname.c_str()); 131 132 int err; 133 { 134 int intFd = fd.get(); 135 AsynchronousSocketCloseMonitor monitor(intFd); 136 err = NET_FAILURE_RETRY(fd, sendto(intFd, byteArray.get() + offset, 137 byteCount, 0, &su.sa, sizeof(su))); 138 } 139 140 return err; 141 } 142 143 /* 144 * Reads a network packet into the user-supplied buffer. Return the 145 * length of the packet, or a 0 if there was a timeout or an 146 * unacceptable packet was acquired. 147 * 148 * Assumes that the caller has validated the offset & byteCount values. 149 */ 150 static jint RawSocket_recvPacket(JNIEnv* env, jclass, jobject fileDescriptor, 151 jbyteArray packet, jint offset, jint byteCount, jint port, 152 jint timeout_millis) 153 { 154 NetFd fd(env, fileDescriptor); 155 if (fd.isClosed()) { 156 return 0; 157 } 158 159 ScopedByteArrayRW body(env, packet); 160 jbyte* packetData = body.get(); 161 if (packetData == NULL) { 162 return 0; 163 } 164 165 packetData += offset; 166 167 pollfd fds[1]; 168 fds[0].fd = fd.get(); 169 fds[0].events = POLLIN; 170 int retval = poll(fds, 1, timeout_millis); 171 if (retval <= 0) { 172 return 0; 173 } 174 175 unsigned int size = 0; 176 { 177 int packetSize = byteCount; 178 int intFd = fd.get(); 179 AsynchronousSocketCloseMonitor monitor(intFd); 180 size = NET_FAILURE_RETRY(fd, read(intFd, packetData, packetSize)); 181 } 182 183 if (env->ExceptionOccurred()) { 184 return 0; 185 } 186 187 if (port != -1) { 188 // quick check for UDP type & UDP port 189 // the packet is an IP header, UDP header, and UDP payload 190 if ((size < (sizeof(struct iphdr) + sizeof(struct udphdr)))) { 191 return 0; // runt packet 192 } 193 194 u_int8_t ip_proto = ((iphdr *) packetData)->protocol; 195 if (ip_proto != IPPROTO_UDP) { 196 return 0; // something other than UDP 197 } 198 199 __be16 destPort = htons((reinterpret_cast<udphdr*>(packetData + sizeof(iphdr)))->dest); 200 if (destPort != port) { 201 return 0; // something other than requested port 202 } 203 } 204 205 return size; 206 } 207 208 static JNINativeMethod gRawMethods[] = { 209 NATIVE_METHOD(RawSocket, create, "(Ljava/io/FileDescriptor;SLjava/lang/String;)V"), 210 NATIVE_METHOD(RawSocket, sendPacket, "(Ljava/io/FileDescriptor;Ljava/lang/String;S[B[BII)I"), 211 NATIVE_METHOD(RawSocket, recvPacket, "(Ljava/io/FileDescriptor;[BIIII)I"), 212 }; 213 214 void register_libcore_net_RawSocket(JNIEnv* env) { 215 jniRegisterNativeMethods(env, "libcore/net/RawSocket", gRawMethods, NELEM(gRawMethods)); 216 } 217