From 0f2cc36572dfb92542e4e910124b725b79dae96c Mon Sep 17 00:00:00 2001 From: Christopher Lane Date: Mon, 17 Mar 2014 16:35:45 -0700 Subject: [PATCH] Add support for custom TXT records in NSD Change-Id: I8e6dc9852ad4d273c71ad6a63a7fbd28a206806d --- core/java/android/net/nsd/NsdServiceInfo.java | 188 +++++++++++++++--- .../java/com/android/server/NsdService.java | 26 ++- 2 files changed, 186 insertions(+), 28 deletions(-) diff --git a/core/java/android/net/nsd/NsdServiceInfo.java b/core/java/android/net/nsd/NsdServiceInfo.java index 205a21d95b..6fdb0d0f84 100644 --- a/core/java/android/net/nsd/NsdServiceInfo.java +++ b/core/java/android/net/nsd/NsdServiceInfo.java @@ -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 mTxtRecord = new ArrayMap(); 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. + * + *

Service attributes are included as DNS-SD TXT record pairs. + * + *

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. + * + *

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. + * + *

The returned map is unmodifiable; changes must be made through {@link #setAttribute} and + * {@link #removeAttribute}. + */ + public Map getAttributes() { + return Collections.unmodifiableMap(mTxtRecord); + } + + private int getTxtRecordSize() { + int txtRecordSize = 0; + for (Map.Entry 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 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; } diff --git a/services/core/java/com/android/server/NsdService.java b/services/core/java/com/android/server/NsdService.java index 93799550dc..8df93f1283 100644 --- a/services/core/java/com/android/server/NsdService.java +++ b/services/core/java/com/android/server/NsdService.java @@ -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 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;