From 1bfcc61a92c252c65c405451542f4ff7191020e9 Mon Sep 17 00:00:00 2001
From: nathan <nathan@dorkbox.com>
Date: Thu, 11 Jan 2018 14:59:33 +0100
Subject: [PATCH] Fixed issues with ensuring appropriate hostName's are FQDN
 (absolute)

---
 src/dorkbox/network/dns/DnsQuestion.java      | 46 ++++++++-----------
 .../network/dns/constants/DnsRecordType.java  | 36 +++++++++++++++
 2 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/src/dorkbox/network/dns/DnsQuestion.java b/src/dorkbox/network/dns/DnsQuestion.java
index 87fd67cc..95899426 100644
--- a/src/dorkbox/network/dns/DnsQuestion.java
+++ b/src/dorkbox/network/dns/DnsQuestion.java
@@ -54,29 +54,31 @@ class DnsQuestion extends DnsMessage implements AddressedEnvelope<DnsQuestion, I
     }
 
 
-
     private static
     DnsQuestion newQuestion(final String inetHost, final int type, final boolean isRecursionDesired, boolean isResolveQuestion) {
 
-        // Convert to ASCII which will also check that the length is not too big.
+        // Convert to ASCII which will also check that the length is not too big. Throws null pointer if null.
         // See:
         //   - https://github.com/netty/netty/issues/4937
         //   - https://github.com/netty/netty/issues/4935
-        String hostname = hostname(checkNotNull(inetHost, "hostname"));
+        String hostName = hostNameAsciiFix(checkNotNull(inetHost, "hostname"));
 
-        if (hostname == null) {
+        hostName = hostName.toLowerCase(Locale.US);
+
+
+        // NOTE: have to make sure that the hostname is a FQDN name
+        hostName = DnsRecordType.ensureFQDN(type, hostName);
+
+        Name name;
+        try {
+            name = Name.fromString(hostName);
+        } catch (Exception e) {
+            // Name.fromString may throw a TextParseException if it fails to parse
             return null;
         }
 
-        hostname = hostname.toLowerCase(Locale.US);
-
-        if (type == DnsRecordType.A || type == DnsRecordType.AAAA) {
-            // resolving a hostname -> ip address, the hostname MUST end in a dot
-            hostname = appendTrailingDot(hostname);
-        }
-
         try {
-            DnsRecord questionRecord = DnsRecord.newRecord(Name.fromString(hostname), type, DnsClass.IN);
+            DnsRecord questionRecord = DnsRecord.newRecord(name, type, DnsClass.IN);
             DnsQuestion question = new DnsQuestion(isResolveQuestion);
             question.getHeader()
                     .setOpcode(DnsOpCode.QUERY);
@@ -92,23 +94,23 @@ class DnsQuestion extends DnsMessage implements AddressedEnvelope<DnsQuestion, I
 
             return question;
         } catch (Exception e) {
-            // Name.fromString may throw a TextParseException if it fails to parse
+            e.printStackTrace();
         }
 
         return null;
     }
 
     public static
-    String hostname(String inetHost) {
+    String hostNameAsciiFix(String inetHost) {
         try {
-            String hostname = java.net.IDN.toASCII(inetHost);
+            String hostName = java.net.IDN.toASCII(inetHost);
 
             // Check for http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6894622
-            if (StringUtil.endsWith(inetHost, '.') && !StringUtil.endsWith(hostname, '.')) {
-                return hostname + '.';
+            if (StringUtil.endsWith(inetHost, '.') && !StringUtil.endsWith(hostName, '.')) {
+                return hostName + '.';
             }
 
-            return hostname;
+            return hostName;
         } catch (Exception e) {
             // java.net.IDN.toASCII(...) may throw an IllegalArgumentException if it fails to parse the hostname
         }
@@ -116,14 +118,6 @@ class DnsQuestion extends DnsMessage implements AddressedEnvelope<DnsQuestion, I
         return null;
     }
 
-    private static
-    String appendTrailingDot(String hostname) {
-        if (!StringUtil.endsWith(hostname, '.')) {
-            return hostname + '.';
-        }
-        return hostname;
-    }
-
     public
     void init(int id, InetSocketAddress recipient) {
         getHeader().setID(id);
diff --git a/src/dorkbox/network/dns/constants/DnsRecordType.java b/src/dorkbox/network/dns/constants/DnsRecordType.java
index db6382e2..058e7ca8 100644
--- a/src/dorkbox/network/dns/constants/DnsRecordType.java
+++ b/src/dorkbox/network/dns/constants/DnsRecordType.java
@@ -8,6 +8,7 @@ import dorkbox.network.dns.Mnemonic;
 import dorkbox.network.dns.exceptions.InvalidTypeException;
 import dorkbox.network.dns.records.DnsRecord;
 import dorkbox.network.dns.records.DnsTypeProtoAssignment;
+import io.netty.util.internal.StringUtil;
 
 /**
  * Constants and functions relating to DNS Types
@@ -562,4 +563,39 @@ class DnsRecordType {
                 return true;
         }
     }
+
+    private static final String ptrSuffix = ".in-addr.arpa";
+    public static
+    String ensureFQDN(int type, String hostName) {
+        // list of RecordTypes from: https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/ResourceRecordTypes.html
+        switch (type) {
+            case PTR:
+                if (!hostName.endsWith(ptrSuffix)) {
+                    // PTR absolutely MUST end in '.in-addr.arpa' in order for the DNS server to understand it.
+                    // in this case, hostname is an ip address
+                    return hostName + ptrSuffix;
+                }
+
+            case A:
+            case AAAA:
+            case CAA:
+            case CNAME:
+            case MX:
+            case NAPTR:
+            case NS:
+            case SOA:
+            case SPF:
+            case SRV:
+            case TXT:
+                // resolving a hostname -> ip address, the hostname MUST end in a dot
+                if (!StringUtil.endsWith(hostName, '.')) {
+                    return hostName + '.';
+                } else {
+                    return hostName;
+                }
+
+            default:
+                return hostName;
+        }
+    }
 }