From e8e3deb056f382e3ec3281dd198f221d59d914b5 Mon Sep 17 00:00:00 2001
From: Ziver Koc <ziver@koc.se>
Date: Tue, 9 Aug 2016 17:57:17 +0200
Subject: [PATCH] Added DNS message compression, it does not handle it right
 now

---
 src/zutil/converter/Converter.java           |   6 +-
 src/zutil/net/dns/DNSPacket.java             |   3 +-
 src/zutil/net/dns/DNSPacketQuestion.java     |  21 ++-
 src/zutil/parser/binary/BinaryFieldData.java |  14 ++
 test/zutil/net/dns/DNSPacketTest.java        | 139 +++++++++++++++++++
 5 files changed, 174 insertions(+), 9 deletions(-)

diff --git a/src/zutil/converter/Converter.java b/src/zutil/converter/Converter.java
index 3aaacee..f490f4e 100755
--- a/src/zutil/converter/Converter.java
+++ b/src/zutil/converter/Converter.java
@@ -128,8 +128,9 @@ public class Converter {
 	 * 
 	 * @param 	hex     is the hex value
 	 * @return a byte that corresponds to the hex
+	 * @throws IllegalArgumentException if hex is not a valid hex character
 	 */
-	public static byte hexToByte( char hex ){
+	public static byte hexToByte( char hex ) throws IllegalArgumentException{
 		switch( Character.toLowerCase(hex) ){
 		case '0': return 0x00;
 		case '1': return 0x01;
@@ -147,8 +148,9 @@ public class Converter {
 		case 'd': return 0x0d;
 		case 'e': return 0x0e;
 		case 'f': return 0x0f;
+		default:
+			throw new IllegalArgumentException("'"+hex+"' is an illegal hex character only 0-9 and a-f characters allowed");
 		}
-		return (byte)0;
 	}
 
 	/** 
diff --git a/src/zutil/net/dns/DNSPacket.java b/src/zutil/net/dns/DNSPacket.java
index c8de49d..bcafcdc 100755
--- a/src/zutil/net/dns/DNSPacket.java
+++ b/src/zutil/net/dns/DNSPacket.java
@@ -11,7 +11,8 @@ import java.util.List;
 /**
  * This class is a general wrapper for a whole DNS packet.
  *
- * Created by Ziver on 2016-04-11.
+ * @see <a href="https://tools.ietf.org/html/rfc1035">rfc1035</a>
+ * @author Ziver on 2016-04-11.
  */
 public class DNSPacket {
     private DNSPacketHeader header;
diff --git a/src/zutil/net/dns/DNSPacketQuestion.java b/src/zutil/net/dns/DNSPacketQuestion.java
index 6e35df6..862bf79 100755
--- a/src/zutil/net/dns/DNSPacketQuestion.java
+++ b/src/zutil/net/dns/DNSPacketQuestion.java
@@ -151,13 +151,22 @@ public class DNSPacketQuestion implements BinaryStruct {
         public String read(InputStream in, BinaryFieldData field) throws IOException {
             StringBuilder str = new StringBuilder();
             int c = in.read();
-            while (c > 0){
-                for (int i=0; i<c; ++i){
-                    str.append((char)in.read());
+            // Is this a pointer
+            if ((c & 0b1100_0000) == 0b1100_0000 ){
+                int offset = (c & 0b0011_1111) << 8;
+                offset |= in.read() & 0b1111_1111;
+                str.append(offset);
+            }
+            // Normal Domain String
+            else {
+                while (c > 0) {
+                    for (int i = 0; i < c; ++i) {
+                        str.append((char) in.read());
+                    }
+                    c = in.read();
+                    if (c > 0)
+                        str.append('.');
                 }
-                c = in.read();
-                if (c > 0)
-                    str.append('.');
             }
             return str.toString();
         }
diff --git a/src/zutil/parser/binary/BinaryFieldData.java b/src/zutil/parser/binary/BinaryFieldData.java
index fe38363..dce0693 100755
--- a/src/zutil/parser/binary/BinaryFieldData.java
+++ b/src/zutil/parser/binary/BinaryFieldData.java
@@ -156,4 +156,18 @@ public class BinaryFieldData {
     public BinaryFieldSerializer getSerializer(){
         return serializer;
     }
+
+
+    @Override
+    public String toString(){
+        return field.getDeclaringClass().getSimpleName() + "::" + field.getName() +
+                " (" +
+                (lengthField != null ?
+                    "LengthField: " + lengthField +", LengthMultiplier: "+lengthMultiplier :
+                    length+" bits") +
+                (serializer != null ?
+                    ", Serializer: " + serializer.getClass().getName() : "") +
+                ")";
+
+    }
 }
\ No newline at end of file
diff --git a/test/zutil/net/dns/DNSPacketTest.java b/test/zutil/net/dns/DNSPacketTest.java
index 6a0f3bc..32ea129 100755
--- a/test/zutil/net/dns/DNSPacketTest.java
+++ b/test/zutil/net/dns/DNSPacketTest.java
@@ -173,4 +173,143 @@ public class DNSPacketTest {
         assertEquals("IPv4", new String(new char[]{0x99, 0x6d, 0x07, 0x5a}), answer.data);
     }
 
+
+    @Test
+    public void rawQuery() throws IOException {
+/*
+Source: http://serverfault.com/questions/173187/what-does-a-dns-request-look-like
+The DNS part starts with 24 1a:
+0000  00 00 00 00 00 00 00 00  00 00 00 00 08 00 45 00   ........ ......E.
+0010  00 3c 51 e3 40 00 40 11  ea cb 7f 00 00 01 7f 00   .<Q.@.@. ........
+0020  00 01 ec ed 00 35 00 28  fe 3b 24 1a 01 00 00 01   .....5.( .;$.....
+0030  00 00 00 00 00 00 03 77  77 77 06 67 6f 6f 67 6c   .......w ww.googl
+0040  65 03 63 6f 6d 00 00 01  00 01                     e.com... ..
+
+Domain Name System (query)
+    [Response In: 1852]
+    Transaction ID: 0x241a
+    Flags: 0x0100 (Standard query)
+        0... .... .... .... = Response: Message is a query
+        .000 0... .... .... = Opcode: Standard query (0)
+        .... ..0. .... .... = Truncated: Message is not truncated
+        .... ...1 .... .... = Recursion desired: Do query recursively
+        .... .... .0.. .... = Z: reserved (0)
+        .... .... ...0 .... = Non-authenticated data OK: Non-authenticated data is unacceptable
+    Questions: 1
+    Answer RRs: 0
+    Authority RRs: 0
+    Additional RRs: 0
+    Queries
+        www.google.com: type A, class IN
+            Name: www.google.com
+            Type: A (Host address)
+            Class: IN (0x0001)
+ */
+// TODO
+    }
+
+    @Test
+    public void rawMultiAnswer() throws IOException {
+/*
+Source: http://serverfault.com/questions/173187/what-does-a-dns-request-look-like
+the repsonse, again starting at 24 1a:
+0000  00 00 00 00 00 00 00 00  00 00 00 00 08 00 45 00   ........ ......E.
+0010  00 7a 00 00 40 00 40 11  3c 71 7f 00 00 01 7f 00   .z..@.@. <q......
+0020  00 01 00 35 ec ed 00 66  fe 79 24 1a 81 80 00 01   ...5...f .y$.....
+0030  00 03 00 00 00 00 03 77  77 77 06 67 6f 6f 67 6c   .......w ww.googl
+0040  65 03 63 6f 6d 00 00 01  00 01 c0 0c 00 05 00 01   e.com... ........
+0050  00 05 28 39 00 12 03 77  77 77 01 6c 06 67 6f 6f   ..(9...w ww.l.goo
+0060  67 6c 65 03 63 6f 6d 00  c0 2c 00 01 00 01 00 00   gle.com. .,......
+0070  00 e3 00 04 42 f9 59 63  c0 2c 00 01 00 01 00 00   ....B.Yc .,......
+0080  00 e3 00 04 42 f9 59 68                            ....B.Yh
+
+Domain Name System (response)
+    [Request In: 1851]
+    [Time: 0.000125000 seconds]
+    Transaction ID: 0x241a
+    Flags: 0x8180 (Standard query response, No error)
+        1... .... .... .... = Response: Message is a response
+        .000 0... .... .... = Opcode: Standard query (0)
+        .... .0.. .... .... = Authoritative: Server is not an authority for domain
+        .... ..0. .... .... = Truncated: Message is not truncated
+        .... ...1 .... .... = Recursion desired: Do query recursively
+        .... .... 1... .... = Recursion available: Server can do recursive queries
+        .... .... .0.. .... = Z: reserved (0)
+        .... .... ..0. .... = Answer authenticated: Answer/authority portion was not authenticated by the server
+        .... .... .... 0000 = Reply code: No error (0)
+    Questions: 1
+    Answer RRs: 3
+    Authority RRs: 0
+    Additional RRs: 0
+    Queries
+        www.google.com: type A, class IN
+            Name: www.google.com
+            Type: A (Host address)
+            Class: IN (0x0001)
+    Answers
+        www.google.com: type CNAME, class IN, cname www.l.google.com
+            Name: www.google.com
+            Type: CNAME (Canonical name for an alias)
+            Class: IN (0x0001)
+            Time to live: 3 days, 21 hours, 52 minutes, 57 seconds
+            Data length: 18
+            Primary name: www.l.google.com
+        www.l.google.com: type A, class IN, addr 66.249.89.99
+            Name: www.l.google.com
+            Type: A (Host address)
+            Class: IN (0x0001)
+            Time to live: 3 minutes, 47 seconds
+            Data length: 4
+            Addr: 66.249.89.99
+        www.l.google.com: type A, class IN, addr 66.249.89.104
+            Name: www.l.google.com
+            Type: A (Host address)
+            Class: IN (0x0001)
+            Time to live: 3 minutes, 47 seconds
+            Data length: 4
+            Addr: 66.249.89.104
+         */
+        byte[] input = Converter.hexToByte((
+                    "24 1a 81 80 00 01 00 03 00 00 00 00" + // Header
+                    "03 77  77 77 06 67 6f 6f 67 6c 65 03 63 6f 6d 00  0001  0001" + // Question
+                    "c00c  0005  0001  00052839  0012  03 77 77 77  01 6c  06 67 6f 6f 67 6c 65  03 63 6f 6d 00" + // Answer1
+                    "c02c  0001  0001  000000e3  0004  42 f9 59 63" + // Answer2
+                    "c02c  0001  0001  000000e3  0004  42 f9 59 68"   // Answer3
+                ).replace(" ", ""));
+        ByteArrayInputStream buffer = new ByteArrayInputStream(input);
+        BinaryStructInputStream in = new BinaryStructInputStream(buffer);
+        DNSPacket packet = DNSPacket.read(in);
+
+        assertEquals("id", 0x241a, packet.getHeader().id);
+        assertTrue("flagQueryResponse", packet.getHeader().flagQueryResponse);
+        assertEquals("No Of Question records", 1, packet.getHeader().countQuestion);
+        assertEquals("No Of Answer records", 3, packet.getHeader().countAnswerRecord);
+        assertEquals("No Of NameServer records", 0, packet.getHeader().countNameServer);
+        assertEquals("No Of Additional records", 0, packet.getHeader().countAdditionalRecord);
+
+        // Query
+        DNSPacketQuestion question = packet.getQuestions().get(0);
+        assertEquals("qNAME", "www.google.com", question.qName);
+        assertEquals("qType", DNSPacketQuestion.QTYPE_A, question.qType);
+        assertEquals("qClass", DNSPacketQuestion.QCLASS_IN, question.qClass);
+
+        // Answer
+        DNSPacketResource answer = packet.getAnswerRecords().get(0);
+        assertEquals("NAME", "12", answer.name);
+        assertEquals("TYPE", TYPE_CNAME, answer.type);
+        assertEquals("CLASS", CLASS_IN, answer.clazz);
+        assertEquals("TTL", 337977, answer.ttl);
+
+        answer = packet.getAnswerRecords().get(1);
+        assertEquals("NAME", "44", answer.name);
+        assertEquals("TYPE", TYPE_A, answer.type);
+        assertEquals("CLASS", CLASS_IN, answer.clazz);
+        assertEquals("TTL", 227, answer.ttl);
+
+        answer = packet.getAnswerRecords().get(2);
+        assertEquals("NAME", "44", answer.name);
+        assertEquals("TYPE", TYPE_A, answer.type);
+        assertEquals("CLASS", CLASS_IN, answer.clazz);
+        assertEquals("TTL", 227, answer.ttl);
+    }
 }