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/*
* Copyright (C) 2018 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.
*/
package android.net.netlink;
import static android.net.netlink.NetlinkConstants.SOCK_DIAG_BY_FAMILY;
import static android.net.netlink.NetlinkSocket.DEFAULT_RECV_BUFSIZE;
import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
import static android.os.Process.INVALID_UID;
import static android.system.OsConstants.AF_INET;
import static android.system.OsConstants.AF_INET6;
import static android.system.OsConstants.IPPROTO_UDP;
import static android.system.OsConstants.NETLINK_INET_DIAG;
import android.annotation.Nullable;
import android.net.util.SocketUtils;
import android.system.ErrnoException;
import android.util.Log;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetSocketAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* A NetlinkMessage subclass for netlink inet_diag messages.
*
* see also: <linux_src>/include/uapi/linux/inet_diag.h
*
* @hide
*/
public class InetDiagMessage extends NetlinkMessage {
public static final String TAG = "InetDiagMessage";
private static final int TIMEOUT_MS = 500;
public static byte[] InetDiagReqV2(int protocol, InetSocketAddress local,
InetSocketAddress remote, int family, short flags) {
return InetDiagReqV2(protocol, local, remote, family, flags, 0 /* pad */,
0 /* idiagExt */, StructInetDiagReqV2.INET_DIAG_REQ_V2_ALL_STATES);
}
/**
* Construct an inet_diag_req_v2 message. This method will throw {@code NullPointerException}
* if local and remote are not both null or both non-null.
*
* @param protocol the request protocol type. This should be set to one of IPPROTO_TCP,
* IPPROTO_UDP, or IPPROTO_UDPLITE.
* @param local local socket address of the target socket. This will be packed into a
* {@Code StructInetDiagSockId}. Request to diagnose for all sockets if both of
* local or remote address is null.
* @param remote remote socket address of the target socket. This will be packed into a
* {@Code StructInetDiagSockId}. Request to diagnose for all sockets if both of
* local or remote address is null.
* @param family the ip family of the request message. This should be set to either AF_INET or
* AF_INET6 for IPv4 or IPv6 sockets respectively.
* @param flags message flags. See <linux_src>/include/uapi/linux/netlink.h.
* @param pad for raw socket protocol specification.
* @param idiagExt a set of flags defining what kind of extended information to report.
* @param state a bit mask that defines a filter of socket states.
*
* @return bytes array representation of the message
**/
public static byte[] InetDiagReqV2(int protocol, @Nullable InetSocketAddress local,
@Nullable InetSocketAddress remote, int family, short flags, int pad, int idiagExt,
int state) throws NullPointerException {
final byte[] bytes = new byte[StructNlMsgHdr.STRUCT_SIZE + StructInetDiagReqV2.STRUCT_SIZE];
final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
byteBuffer.order(ByteOrder.nativeOrder());
final StructNlMsgHdr nlMsgHdr = new StructNlMsgHdr();
nlMsgHdr.nlmsg_len = bytes.length;
nlMsgHdr.nlmsg_type = SOCK_DIAG_BY_FAMILY;
nlMsgHdr.nlmsg_flags = flags;
nlMsgHdr.pack(byteBuffer);
final StructInetDiagReqV2 inetDiagReqV2 =
new StructInetDiagReqV2(protocol, local, remote, family, pad, idiagExt, state);
inetDiagReqV2.pack(byteBuffer);
return bytes;
}
public StructInetDiagMsg mStructInetDiagMsg;
private InetDiagMessage(StructNlMsgHdr header) {
super(header);
mStructInetDiagMsg = new StructInetDiagMsg();
}
public static InetDiagMessage parse(StructNlMsgHdr header, ByteBuffer byteBuffer) {
final InetDiagMessage msg = new InetDiagMessage(header);
msg.mStructInetDiagMsg = StructInetDiagMsg.parse(byteBuffer);
return msg;
}
private static int lookupUidByFamily(int protocol, InetSocketAddress local,
InetSocketAddress remote, int family, short flags,
FileDescriptor fd)
throws ErrnoException, InterruptedIOException {
byte[] msg = InetDiagReqV2(protocol, local, remote, family, flags);
NetlinkSocket.sendMessage(fd, msg, 0, msg.length, TIMEOUT_MS);
ByteBuffer response = NetlinkSocket.recvMessage(fd, DEFAULT_RECV_BUFSIZE, TIMEOUT_MS);
final NetlinkMessage nlMsg = NetlinkMessage.parse(response);
final StructNlMsgHdr hdr = nlMsg.getHeader();
if (hdr.nlmsg_type == NetlinkConstants.NLMSG_DONE) {
return INVALID_UID;
}
if (nlMsg instanceof InetDiagMessage) {
return ((InetDiagMessage) nlMsg).mStructInetDiagMsg.idiag_uid;
}
return INVALID_UID;
}
private static final int FAMILY[] = {AF_INET6, AF_INET};
private static int lookupUid(int protocol, InetSocketAddress local,
InetSocketAddress remote, FileDescriptor fd)
throws ErrnoException, InterruptedIOException {
int uid;
for (int family : FAMILY) {
/**
* For exact match lookup, swap local and remote for UDP lookups due to kernel
* bug which will not be fixed. See aosp/755889 and
* https://www.mail-archive.com/netdev@vger.kernel.org/msg248638.html
*/
if (protocol == IPPROTO_UDP) {
uid = lookupUidByFamily(protocol, remote, local, family, NLM_F_REQUEST, fd);
} else {
uid = lookupUidByFamily(protocol, local, remote, family, NLM_F_REQUEST, fd);
}
if (uid != INVALID_UID) {
return uid;
}
}
/**
* For UDP it's possible for a socket to send packets to arbitrary destinations, even if the
* socket is not connected (and even if the socket is connected to a different destination).
* If we want this API to work for such packets, then on miss we need to do a second lookup
* with only the local address and port filled in.
* Always use flags == NLM_F_REQUEST | NLM_F_DUMP for wildcard.
*/
if (protocol == IPPROTO_UDP) {
try {
InetSocketAddress wildcard = new InetSocketAddress(
Inet6Address.getByName("::"), 0);
uid = lookupUidByFamily(protocol, local, wildcard, AF_INET6,
(short) (NLM_F_REQUEST | NLM_F_DUMP), fd);
if (uid != INVALID_UID) {
return uid;
}
wildcard = new InetSocketAddress(Inet4Address.getByName("0.0.0.0"), 0);
uid = lookupUidByFamily(protocol, local, wildcard, AF_INET,
(short) (NLM_F_REQUEST | NLM_F_DUMP), fd);
if (uid != INVALID_UID) {
return uid;
}
} catch (UnknownHostException e) {
Log.e(TAG, e.toString());
}
}
return INVALID_UID;
}
/**
* Use an inet_diag socket to look up the UID associated with the input local and remote
* address/port and protocol of a connection.
*/
public static int getConnectionOwnerUid(int protocol, InetSocketAddress local,
InetSocketAddress remote) {
int uid = INVALID_UID;
FileDescriptor fd = null;
try {
fd = NetlinkSocket.forProto(NETLINK_INET_DIAG);
NetlinkSocket.connectToKernel(fd);
uid = lookupUid(protocol, local, remote, fd);
} catch (ErrnoException | SocketException | IllegalArgumentException
| InterruptedIOException e) {
Log.e(TAG, e.toString());
} finally {
if (fd != null) {
try {
SocketUtils.closeSocket(fd);
} catch (IOException e) {
Log.e(TAG, e.toString());
}
}
}
return uid;
}
@Override
public String toString() {
return "InetDiagMessage{ "
+ "nlmsghdr{" + (mHeader == null ? "" : mHeader.toString()) + "}, "
+ "inet_diag_msg{"
+ (mStructInetDiagMsg == null ? "" : mStructInetDiagMsg.toString()) + "} "
+ "}";
}
}
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