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/*
* Copyright (C) 2019 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 com.android.networkstack.netlink;
import android.util.Log;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.android.internal.annotations.VisibleForTesting;
import java.nio.BufferOverflowException;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.util.Objects;
/**
* Class for tcp_info.
*
* Corresponds to {@code struct tcp_info} from bionic/libc/kernel/uapi/linux/tcp.h
*/
public class TcpInfo {
public enum Field {
STATE(Byte.BYTES),
CASTATE(Byte.BYTES),
RETRANSMITS(Byte.BYTES),
PROBES(Byte.BYTES),
BACKOFF(Byte.BYTES),
OPTIONS(Byte.BYTES),
WSCALE(Byte.BYTES),
DELIVERY_RATE_APP_LIMITED(Byte.BYTES),
RTO(Integer.BYTES),
ATO(Integer.BYTES),
SND_MSS(Integer.BYTES),
RCV_MSS(Integer.BYTES),
UNACKED(Integer.BYTES),
SACKED(Integer.BYTES),
LOST(Integer.BYTES),
RETRANS(Integer.BYTES),
FACKETS(Integer.BYTES),
LAST_DATA_SENT(Integer.BYTES),
LAST_ACK_SENT(Integer.BYTES),
LAST_DATA_RECV(Integer.BYTES),
LAST_ACK_RECV(Integer.BYTES),
PMTU(Integer.BYTES),
RCV_SSTHRESH(Integer.BYTES),
RTT(Integer.BYTES),
RTTVAR(Integer.BYTES),
SND_SSTHRESH(Integer.BYTES),
SND_CWND(Integer.BYTES),
ADVMSS(Integer.BYTES),
REORDERING(Integer.BYTES),
RCV_RTT(Integer.BYTES),
RCV_SPACE(Integer.BYTES),
TOTAL_RETRANS(Integer.BYTES),
PACING_RATE(Long.BYTES),
MAX_PACING_RATE(Long.BYTES),
BYTES_ACKED(Long.BYTES),
BYTES_RECEIVED(Long.BYTES),
SEGS_OUT(Integer.BYTES),
SEGS_IN(Integer.BYTES),
NOTSENT_BYTES(Integer.BYTES),
MIN_RTT(Integer.BYTES),
DATA_SEGS_IN(Integer.BYTES),
DATA_SEGS_OUT(Integer.BYTES),
DELIVERY_RATE(Long.BYTES),
BUSY_TIME(Long.BYTES),
RWND_LIMITED(Long.BYTES),
SNDBUF_LIMITED(Long.BYTES);
public final int size;
Field(int s) {
size = s;
}
}
private static final String TAG = "TcpInfo";
@VisibleForTesting
static final int LOST_OFFSET = getFieldOffset(Field.LOST);
@VisibleForTesting
static final int RETRANSMITS_OFFSET = getFieldOffset(Field.RETRANSMITS);
@VisibleForTesting
static final int SEGS_IN_OFFSET = getFieldOffset(Field.SEGS_IN);
@VisibleForTesting
static final int SEGS_OUT_OFFSET = getFieldOffset(Field.SEGS_OUT);
final int mSegsIn;
final int mSegsOut;
final int mLost;
final int mRetransmits;
private static int getFieldOffset(@NonNull final Field needle) {
int offset = 0;
for (final Field field : Field.values()) {
if (field == needle) return offset;
offset += field.size;
}
throw new IllegalArgumentException("Unknown field");
}
private TcpInfo(@NonNull ByteBuffer bytes, int infolen) {
// SEGS_IN is the last required field in the buffer, so if the buffer is long enough for
// SEGS_IN it's long enough for everything
if (SEGS_IN_OFFSET + Field.SEGS_IN.size > infolen) {
throw new IllegalArgumentException("Length " + infolen + " is less than required.");
}
final int start = bytes.position();
mSegsIn = bytes.getInt(start + SEGS_IN_OFFSET);
mSegsOut = bytes.getInt(start + SEGS_OUT_OFFSET);
mLost = bytes.getInt(start + LOST_OFFSET);
mRetransmits = bytes.get(start + RETRANSMITS_OFFSET);
// tcp_info structure grows over time as new fields are added. Jump to the end of the
// structure, as unknown fields might remain at the end of the structure if the tcp_info
// struct was expanded.
bytes.position(Math.min(infolen + start, bytes.limit()));
}
@VisibleForTesting
TcpInfo(int retransmits, int lost, int segsOut, int segsIn) {
mRetransmits = retransmits;
mLost = lost;
mSegsOut = segsOut;
mSegsIn = segsIn;
}
/** Parse a TcpInfo from a giving ByteBuffer with a specific length. */
@Nullable
public static TcpInfo parse(@NonNull ByteBuffer bytes, int infolen) {
try {
return new TcpInfo(bytes, infolen);
} catch (BufferUnderflowException | BufferOverflowException | IllegalArgumentException
| IndexOutOfBoundsException e) {
Log.e(TAG, "parsing error.", e);
return null;
}
}
private static String decodeWscale(byte num) {
return String.valueOf((num >> 4) & 0x0f) + ":" + String.valueOf(num & 0x0f);
}
/**
* Returns a string representing a given tcp state.
* Map to enum in bionic/libc/include/netinet/tcp.h
*/
@VisibleForTesting
static String getTcpStateName(int state) {
switch (state) {
case 1: return "TCP_ESTABLISHED";
case 2: return "TCP_SYN_SENT";
case 3: return "TCP_SYN_RECV";
case 4: return "TCP_FIN_WAIT1";
case 5: return "TCP_FIN_WAIT2";
case 6: return "TCP_TIME_WAIT";
case 7: return "TCP_CLOSE";
case 8: return "TCP_CLOSE_WAIT";
case 9: return "TCP_LAST_ACK";
case 10: return "TCP_LISTEN";
case 11: return "TCP_CLOSING";
default: return "UNKNOWN:" + Integer.toString(state);
}
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof TcpInfo)) return false;
TcpInfo other = (TcpInfo) obj;
return mSegsIn == other.mSegsIn && mSegsOut == other.mSegsOut
&& mRetransmits == other.mRetransmits && mLost == other.mLost;
}
@Override
public int hashCode() {
return Objects.hash(mLost, mRetransmits, mSegsIn, mSegsOut);
}
@Override
public String toString() {
return "TcpInfo{lost=" + mLost + ", retransmit=" + mRetransmits + ", received=" + mSegsIn
+ ", sent=" + mSegsOut + "}";
}
}
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