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Merge "Minor changes to the async DNS query JAVA API" am: c8dfb72891

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am: 5b0b36a6b4

Change-Id: Ib1e317597d33a460e80a4efc63835754c1c1b3c7
This commit is contained in:
Luke Huang
2019-03-08 07:56:33 -08:00
committed by android-build-merger
parent 656fadca4f 5b0b36a6b4
commit 6a047b2645
3 changed files with 81 additions and 69 deletions
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77
core/java/android/net/DnsPacket.java
View File

@@ -28,7 +28,6 @@ import java.text.DecimalFormat;
import java.text.FieldPosition;
import java.util.ArrayList;
import java.util.List;
import java.util.StringJoiner;
/**
* Defines basic data for DNS protocol based on RFC 1035.
@@ -42,7 +41,7 @@ public abstract class DnsPacket {
public final int id;
public final int flags;
public final int rcode;
private final int[] mSectionCount;
private final int[] mRecordCount;
/**
* Create a new DnsHeader from a positioned ByteBuffer.
@@ -52,27 +51,32 @@ public abstract class DnsPacket {
* When this constructor returns, the reading position of the ByteBuffer has been
* advanced to the end of the DNS header record.
* This is meant to chain with other methods reading a DNS response in sequence.
*
*/
DnsHeader(@NonNull ByteBuffer buf) throws BufferUnderflowException {
id = BitUtils.uint16(buf.getShort());
flags = BitUtils.uint16(buf.getShort());
rcode = flags & 0xF;
mSectionCount = new int[NUM_SECTIONS];
mRecordCount = new int[NUM_SECTIONS];
for (int i = 0; i < NUM_SECTIONS; ++i) {
mSectionCount[i] = BitUtils.uint16(buf.getShort());
mRecordCount[i] = BitUtils.uint16(buf.getShort());
}
}
/**
* Get section count by section type.
* Get record count by type.
*/
public int getSectionCount(int sectionType) {
return mSectionCount[sectionType];
public int getRecordCount(int type) {
return mRecordCount[type];
}
}
public class DnsSection {
/**
* It's used both for DNS questions and DNS resource records.
*
* DNS questions (No TTL/RDATA)
* DNS resource records (With TTL/RDATA)
*/
public class DnsRecord {
private static final int MAXNAMESIZE = 255;
private static final int MAXLABELSIZE = 63;
private static final int MAXLABELCOUNT = 128;
@@ -81,57 +85,57 @@ public abstract class DnsPacket {
private final DecimalFormat byteFormat = new DecimalFormat();
private final FieldPosition pos = new FieldPosition(0);
private static final String TAG = "DnsSection";
private static final String TAG = "DnsRecord";
public final String dName;
public final int nsType;
public final int nsClass;
public final long ttl;
private final byte[] mRR;
private final byte[] mRdata;
/**
* Create a new DnsSection from a positioned ByteBuffer.
* Create a new DnsRecord from a positioned ByteBuffer.
*
* The ByteBuffer must be in network byte order (which is the default).
* Reads the passed ByteBuffer from its current position and decodes a DNS section.
* @param ByteBuffer input of record, must be in network byte order
* (which is the default).
* Reads the passed ByteBuffer from its current position and decodes a DNS record.
* When this constructor returns, the reading position of the ByteBuffer has been
* advanced to the end of the DNS header record.
* This is meant to chain with other methods reading a DNS response in sequence.
*
*/
DnsSection(int sectionType, @NonNull ByteBuffer buf)
DnsRecord(int recordType, @NonNull ByteBuffer buf)
throws BufferUnderflowException, ParseException {
dName = parseName(buf, 0 /* Parse depth */);
if (dName.length() > MAXNAMESIZE) {
throw new ParseException("Parse name fail, name size is too long");
throw new ParseException(
"Parse name fail, name size is too long: " + dName.length());
}
nsType = BitUtils.uint16(buf.getShort());
nsClass = BitUtils.uint16(buf.getShort());
if (sectionType != QDSECTION) {
if (recordType != QDSECTION) {
ttl = BitUtils.uint32(buf.getInt());
final int length = BitUtils.uint16(buf.getShort());
mRR = new byte[length];
buf.get(mRR);
mRdata = new byte[length];
buf.get(mRdata);
} else {
ttl = 0;
mRR = null;
mRdata = null;
}
}
/**
* Get a copy of rr.
* Get a copy of rdata.
*/
@Nullable public byte[] getRR() {
return (mRR == null) ? null : mRR.clone();
@Nullable
public byte[] getRR() {
return (mRdata == null) ? null : mRdata.clone();
}
/**
* Convert label from {@code byte[]} to {@code String}
*
* It follows the same converting rule as native layer.
* (See ns_name.c in libc)
*
* Follows the same conversion rules of the native code (ns_name.c in libc)
*/
private String labelToString(@NonNull byte[] label) {
final StringBuffer sb = new StringBuffer();
@@ -139,13 +143,16 @@ public abstract class DnsPacket {
int b = BitUtils.uint8(label[i]);
// Control characters and non-ASCII characters.
if (b <= 0x20 || b >= 0x7f) {
// Append the byte as an escaped decimal number, e.g., "\19" for 0x13.
sb.append('\\');
byteFormat.format(b, sb, pos);
} else if (b == '"' || b == '.' || b == ';' || b == '\\'
|| b == '(' || b == ')' || b == '@' || b == '$') {
// Append the byte as an escaped character, e.g., "\:" for 0x3a.
sb.append('\\');
sb.append((char) b);
} else {
// Append the byte as a character, e.g., "a" for 0x61.
sb.append((char) b);
}
}
@@ -154,7 +161,9 @@ public abstract class DnsPacket {
private String parseName(@NonNull ByteBuffer buf, int depth) throws
BufferUnderflowException, ParseException {
if (depth > MAXLABELCOUNT) throw new ParseException("Parse name fails, too many labels");
if (depth > MAXLABELCOUNT) {
throw new ParseException("Failed to parse name, too many labels");
}
final int len = BitUtils.uint8(buf.get());
final int mask = len & NAME_COMPRESSION;
if (0 == len) {
@@ -194,7 +203,7 @@ public abstract class DnsPacket {
private static final String TAG = DnsPacket.class.getSimpleName();
protected final DnsHeader mHeader;
protected final List<DnsSection>[] mSections;
protected final List<DnsRecord>[] mRecords;
public static class ParseException extends Exception {
public ParseException(String msg) {
@@ -216,18 +225,18 @@ public abstract class DnsPacket {
throw new ParseException("Parse Header fail, bad input data", e);
}
mSections = new ArrayList[NUM_SECTIONS];
mRecords = new ArrayList[NUM_SECTIONS];
for (int i = 0; i < NUM_SECTIONS; ++i) {
final int count = mHeader.getSectionCount(i);
final int count = mHeader.getRecordCount(i);
if (count > 0) {
mSections[i] = new ArrayList(count);
mRecords[i] = new ArrayList(count);
}
for (int j = 0; j < count; ++j) {
try {
mSections[i].add(new DnsSection(i, buffer));
mRecords[i].add(new DnsRecord(i, buffer));
} catch (BufferUnderflowException e) {
throw new ParseException("Parse section fail", e);
throw new ParseException("Parse record fail", e);
}
}
}

13
core/java/android/net/DnsResolver.java
View File

@@ -43,6 +43,9 @@ import java.util.function.Consumer;
/**
* Dns resolver class for asynchronous dns querying
*
* Note that if a client sends a query with more than 1 record in the question section but
* the remote dns server does not support this, it may not respond at all, leading to a timeout.
*
*/
public final class DnsResolver {
private static final String TAG = "DnsResolver";
@@ -226,19 +229,19 @@ public final class DnsResolver {
if (mHeader.rcode != 0) {
throw new ParseException("Response error, rcode:" + mHeader.rcode);
}
if (mHeader.getSectionCount(ANSECTION) == 0) {
if (mHeader.getRecordCount(ANSECTION) == 0) {
throw new ParseException("No available answer");
}
if (mHeader.getSectionCount(QDSECTION) == 0) {
if (mHeader.getRecordCount(QDSECTION) == 0) {
throw new ParseException("No question found");
}
// Assume only one question per answer packet. (RFC1035)
mQueryType = mSections[QDSECTION].get(0).nsType;
// Expect only one question in question section.
mQueryType = mRecords[QDSECTION].get(0).nsType;
}
public @NonNull List<InetAddress> getAddresses() {
final List<InetAddress> results = new ArrayList<InetAddress>();
for (final DnsSection ansSec : mSections[ANSECTION]) {
for (final DnsRecord ansSec : mRecords[ANSECTION]) {
// Only support A and AAAA, also ignore answers if query type != answer type.
int nsType = ansSec.nsType;
if (nsType != mQueryType || (nsType != TYPE_A && nsType != TYPE_AAAA)) {