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Add support for custom TXT records in NSD

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Change-Id: I8e6dc9852ad4d273c71ad6a63a7fbd28a206806d
This commit is contained in:
Christopher Lane
2014-03-17 16:35:45 -07:00
parent 5da9a41811
commit 0f2cc36572
2 changed files with 186 additions and 28 deletions
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188
core/java/android/net/nsd/NsdServiceInfo.java
View File

@@ -18,8 +18,15 @@ package android.net.nsd;
import android.os.Parcelable;
import android.os.Parcel;
import android.util.Log;
import android.util.ArrayMap;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.Map;
/**
* A class representing service information for network service discovery
@@ -27,11 +34,13 @@ import java.net.InetAddress;
*/
public final class NsdServiceInfo implements Parcelable {
private static final String TAG = "NsdServiceInfo";
private String mServiceName;
private String mServiceType;
private DnsSdTxtRecord mTxtRecord;
private final ArrayMap<String, byte[]> mTxtRecord = new ArrayMap<String, byte[]>();
private InetAddress mHost;
@@ -41,10 +50,9 @@ public final class NsdServiceInfo implements Parcelable {
}
/** @hide */
public NsdServiceInfo(String sn, String rt, DnsSdTxtRecord tr) {
public NsdServiceInfo(String sn, String rt) {
mServiceName = sn;
mServiceType = rt;
mTxtRecord = tr;
}
/** Get the service name */
@@ -67,16 +75,6 @@ public final class NsdServiceInfo implements Parcelable {
mServiceType = s;
}
/** @hide */
public DnsSdTxtRecord getTxtRecord() {
return mTxtRecord;
}
/** @hide */
public void setTxtRecord(DnsSdTxtRecord t) {
mTxtRecord = new DnsSdTxtRecord(t);
}
/** Get the host address. The host address is valid for a resolved service. */
public InetAddress getHost() {
return mHost;
@@ -97,14 +95,134 @@ public final class NsdServiceInfo implements Parcelable {
mPort = p;
}
/** @hide */
public void setAttribute(String key, byte[] value) {
// Key must be printable US-ASCII, excluding =.
for (int i = 0; i < key.length(); ++i) {
char character = key.charAt(i);
if (character < 0x20 || character > 0x7E) {
throw new IllegalArgumentException("Key strings must be printable US-ASCII");
} else if (character == 0x3D) {
throw new IllegalArgumentException("Key strings must not include '='");
}
}
// Key length + value length must be < 255.
if (key.length() + (value == null ? 0 : value.length) >= 255) {
throw new IllegalArgumentException("Key length + value length must be < 255 bytes");
}
// Warn if key is > 9 characters, as recommended by RFC 6763 section 6.4.
if (key.length() > 9) {
Log.w(TAG, "Key lengths > 9 are discouraged: " + key);
}
// Check against total TXT record size limits.
// Arbitrary 400 / 1300 byte limits taken from RFC 6763 section 6.2.
int txtRecordSize = getTxtRecordSize();
int futureSize = txtRecordSize + key.length() + (value == null ? 0 : value.length) + 2;
if (futureSize > 1300) {
throw new IllegalArgumentException("Total length of attributes must be < 1300 bytes");
} else if (futureSize > 400) {
Log.w(TAG, "Total length of all attributes exceeds 400 bytes; truncation may occur");
}
mTxtRecord.put(key, value);
}
/**
* Add a service attribute as a key/value pair.
*
* <p> Service attributes are included as DNS-SD TXT record pairs.
*
* <p> The key must be US-ASCII printable characters, excluding the '=' character. Values may
* be UTF-8 strings or null. The total length of key + value must be less than 255 bytes.
*
* <p> Keys should be short, ideally no more than 9 characters, and unique per instance of
* {@link NsdServiceInfo}. Calling {@link #setAttribute} twice with the same key will overwrite
* first value.
*/
public void setAttribute(String key, String value) {
try {
setAttribute(key, value == null ? (byte []) null : value.getBytes("UTF-8"));
} catch (UnsupportedEncodingException e) {
throw new IllegalArgumentException("Value must be UTF-8");
}
}
/** Remove an attribute by key */
public void removeAttribute(String key) {
mTxtRecord.remove(key);
}
/**
* Retrive attributes as a map of String keys to byte[] values.
*
* <p> The returned map is unmodifiable; changes must be made through {@link #setAttribute} and
* {@link #removeAttribute}.
*/
public Map<String, byte[]> getAttributes() {
return Collections.unmodifiableMap(mTxtRecord);
}
private int getTxtRecordSize() {
int txtRecordSize = 0;
for (Map.Entry<String, byte[]> entry : mTxtRecord.entrySet()) {
txtRecordSize += 2; // One for the length byte, one for the = between key and value.
txtRecordSize += entry.getKey().length();
byte[] value = entry.getValue();
txtRecordSize += value == null ? 0 : value.length;
}
return txtRecordSize;
}
/** @hide */
public byte[] getTxtRecord() {
int txtRecordSize = getTxtRecordSize();
if (txtRecordSize == 0) {
return null;
}
byte[] txtRecord = new byte[txtRecordSize];
int ptr = 0;
for (Map.Entry<String, byte[]> entry : mTxtRecord.entrySet()) {
String key = entry.getKey();
byte[] value = entry.getValue();
// One byte to record the length of this key/value pair.
txtRecord[ptr++] = (byte) (key.length() + (value == null ? 0 : value.length) + 1);
// The key, in US-ASCII.
// Note: use the StandardCharsets const here because it doesn't raise exceptions and we
// already know the key is ASCII at this point.
System.arraycopy(key.getBytes(StandardCharsets.US_ASCII), 0, txtRecord, ptr,
key.length());
ptr += key.length();
// US-ASCII '=' character.
txtRecord[ptr++] = (byte)'=';
// The value, as any raw bytes.
if (value != null) {
System.arraycopy(value, 0, txtRecord, ptr, value.length);
ptr += value.length;
}
}
return txtRecord;
}
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("name: ").append(mServiceName).
append("type: ").append(mServiceType).
append("host: ").append(mHost).
append("port: ").append(mPort).
append("txtRecord: ").append(mTxtRecord);
sb.append("name: ").append(mServiceName)
.append(", type: ").append(mServiceType)
.append(", host: ").append(mHost)
.append(", port: ").append(mPort);
byte[] txtRecord = getTxtRecord();
if (txtRecord != null) {
sb.append(", txtRecord: ").append(new String(txtRecord, StandardCharsets.UTF_8));
}
return sb.toString();
}
@@ -117,14 +235,27 @@ public final class NsdServiceInfo implements Parcelable {
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(mServiceName);
dest.writeString(mServiceType);
dest.writeParcelable(mTxtRecord, flags);
if (mHost != null) {
dest.writeByte((byte)1);
dest.writeInt(1);
dest.writeByteArray(mHost.getAddress());
} else {
dest.writeByte((byte)0);
dest.writeInt(0);
}
dest.writeInt(mPort);
// TXT record key/value pairs.
dest.writeInt(mTxtRecord.size());
for (String key : mTxtRecord.keySet()) {
byte[] value = mTxtRecord.get(key);
if (value != null) {
dest.writeInt(1);
dest.writeInt(value.length);
dest.writeByteArray(value);
} else {
dest.writeInt(0);
}
dest.writeString(key);
}
}
/** Implement the Parcelable interface */
@@ -134,15 +265,26 @@ public final class NsdServiceInfo implements Parcelable {
NsdServiceInfo info = new NsdServiceInfo();
info.mServiceName = in.readString();
info.mServiceType = in.readString();
info.mTxtRecord = in.readParcelable(null);
if (in.readByte() == 1) {
if (in.readInt() == 1) {
try {
info.mHost = InetAddress.getByAddress(in.createByteArray());
} catch (java.net.UnknownHostException e) {}
}
info.mPort = in.readInt();
// TXT record key/value pairs.
int recordCount = in.readInt();
for (int i = 0; i < recordCount; ++i) {
byte[] valueArray = null;
if (in.readInt() == 1) {
int valueLength = in.readInt();
valueArray = new byte[valueLength];
in.readByteArray(valueArray);
}
info.mTxtRecord.put(in.readString(), valueArray);
}
return info;
}

26
services/core/java/com/android/server/NsdService.java
View File

@@ -38,10 +38,13 @@ import android.util.SparseArray;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import com.android.internal.app.IBatteryStats;
@@ -443,14 +446,14 @@ public class NsdService extends INsdManager.Stub {
case NativeResponseCode.SERVICE_FOUND:
/* NNN uniqueId serviceName regType domain */
if (DBG) Slog.d(TAG, "SERVICE_FOUND Raw: " + raw);
servInfo = new NsdServiceInfo(cooked[2], cooked[3], null);
servInfo = new NsdServiceInfo(cooked[2], cooked[3]);
clientInfo.mChannel.sendMessage(NsdManager.SERVICE_FOUND, 0,
clientId, servInfo);
break;
case NativeResponseCode.SERVICE_LOST:
/* NNN uniqueId serviceName regType domain */
if (DBG) Slog.d(TAG, "SERVICE_LOST Raw: " + raw);
servInfo = new NsdServiceInfo(cooked[2], cooked[3], null);
servInfo = new NsdServiceInfo(cooked[2], cooked[3]);
clientInfo.mChannel.sendMessage(NsdManager.SERVICE_LOST, 0,
clientId, servInfo);
break;
@@ -463,7 +466,7 @@ public class NsdService extends INsdManager.Stub {
case NativeResponseCode.SERVICE_REGISTERED:
/* NNN regId serviceName regType */
if (DBG) Slog.d(TAG, "SERVICE_REGISTERED Raw: " + raw);
servInfo = new NsdServiceInfo(cooked[2], null, null);
servInfo = new NsdServiceInfo(cooked[2], null);
clientInfo.mChannel.sendMessage(NsdManager.REGISTER_SERVICE_SUCCEEDED,
id, clientId, servInfo);
break;
@@ -679,9 +682,22 @@ public class NsdService extends INsdManager.Stub {
private boolean registerService(int regId, NsdServiceInfo service) {
if (DBG) Slog.d(TAG, "registerService: " + regId + " " + service);
try {
//Add txtlen and txtdata
mNativeConnector.execute("mdnssd", "register", regId, service.getServiceName(),
Command cmd = new Command("mdnssd", "register", regId, service.getServiceName(),
service.getServiceType(), service.getPort());
// Add TXT records as additional arguments.
Map<String, byte[]> txtRecords = service.getAttributes();
for (String key : txtRecords.keySet()) {
try {
// TODO: Send encoded TXT record as bytes once NDC/netd supports binary data.
cmd.appendArg(String.format(Locale.US, "%s=%s", key,
new String(txtRecords.get(key), "UTF_8")));
} catch (UnsupportedEncodingException e) {
Slog.e(TAG, "Failed to encode txtRecord " + e);
}
}
mNativeConnector.execute(cmd);
} catch(NativeDaemonConnectorException e) {
Slog.e(TAG, "Failed to execute registerService " + e);
return false;