Support TXT record splitting

Habbie · Apr 15, 2018 · 8f8ae55 · 8f8ae55
1 parent ec773d4
commit 8f8ae55
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Showing 3 changed files with 20 additions and 5 deletions.
diff --git a/tdns/contents.cc b/tdns/contents.cc
@@ -40,6 +40,8 @@ void loadZones(DNSNode& zones)
   newzone->add({"ent", "was", "here"})->addRRs(TXTGen::make("plenum"));
   newzone->add({"some.embedded.dots"})->addRRs(TXTGen::make("what do the dots look like?"));
 
+  newzone->add({"split"})->addRRs(TXTGen::make("hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello world hello"));
+  newzone->add({"split"})->addRRs(TXTGen::make({{"this is the first part"},{"this is the second part"}}));
 
   const char zero[]="name-does-not-stop-here\x0-it-goes-on";
   std::string zstring(zero, sizeof(zero)-1);

diff --git a/tdns/record-types.cc b/tdns/record-types.cc
@@ -53,9 +53,14 @@ void MXGen::toMessage(DNSMessageWriter& dmw)
 
 void TXTGen::toMessage(DNSMessageWriter& dmw) 
 {
-  // XXX should autosplit
-  dmw.putUInt8(d_txt.length());
-  dmw.putBlob(d_txt);
+  for(auto segment: d_txts) {
+    while(segment.length() > 0) {
+      const auto fragment = segment.substr(0, 254);
+      dmw.putUInt8(fragment.length());
+      dmw.putBlob(fragment);
+      segment.erase(0, fragment.length());
+    }
+  }
 }
 
 void ClockTXTGen::toMessage(DNSMessageWriter& dmw) 

diff --git a/tdns/record-types.hh b/tdns/record-types.hh
@@ -90,14 +90,22 @@ struct MXGen : RRGen
 
 struct TXTGen : RRGen
 {
-  TXTGen(const std::string& txt) : d_txt(txt) {}
+  TXTGen(const std::vector<std::string>& txts) : d_txts(txts) {}
+  TXTGen(const std::string& txt) : d_txts({txt}) {}
+
+  static std::unique_ptr<RRGen> make(const std::vector<std::string>& txts)
+  {
+    return std::make_unique<TXTGen>(txts);
+  }
+
   static std::unique_ptr<RRGen> make(const std::string& txt)
   {
     return std::make_unique<TXTGen>(txt);
   }
+
   void toMessage(DNSMessageWriter& dpw) override;
   DNSType getType() const override { return DNSType::TXT; }
-  std::string d_txt;
+  std::vector<std::string> d_txts;
 };
 
 struct ClockTXTGen : RRGen