SRV records fixes (#1332)

* fix a log print log level

* correctly match SRV record service and protocol...

* tests for new dns question functions

llarp/dns/question.cpp

@@ -2,6 +2,7 @@
 
 #include <util/logging/logger.hpp>
 #include <util/printer.hpp>
+#include <util/str.hpp>
 
 namespace llarp
 {
@@ -59,6 +60,31 @@ namespace llarp
       return IsName(other + ".");
     }
 
+    bool
+    Question::IsLocalhost() const
+    {
+      return (qname == "localhost.loki." or llarp::ends_with(qname, ".localhost.loki."));
+    }
+
+    std::string
+    Question::Subdomains() const
+    {
+      if (qname.size() < 2)
+        return "";
+
+      size_t pos;
+
+      pos = qname.rfind('.', qname.size() - 2);
+      if (pos == std::string::npos or pos == 0)
+        return "";
+
+      pos = qname.rfind('.', pos - 1);
+      if (pos == std::string::npos or pos == 0)
+        return "";
+
+      return qname.substr(0, pos);
+    }
+
     std::string
     Question::Name() const
     {

llarp/dns/question.hpp

@@ -40,6 +40,14 @@ namespace llarp
       bool
       IsName(const std::string& other) const;
 
+      /// is the name [something.]localhost.loki. ?
+      bool
+      IsLocalhost() const;
+
+      /// get subdomain(s), if any, from qname
+      std::string
+      Subdomains() const;
+
       /// return qname with no trailing .
       std::string
       Name() const;

llarp/handlers/tun.cpp

@@ -245,7 +245,7 @@ namespace llarp
     static bool
     is_localhost_loki(const dns::Message& msg)
     {
-      return msg.questions[0].IsName("localhost.loki");
+      return msg.questions[0].IsLocalhost();
     }
 
     template <>
@@ -324,17 +324,7 @@ namespace llarp
                 return;
 
               const auto& introset = ctx->GetCurrentIntroSet();
-              std::vector<llarp::dns::SRVData> records;
-              size_t numRecords = introset.SRVs.size();
-              if (numRecords > 0)
-              {
-                records.reserve(numRecords);
-                for (const auto& record : introset.SRVs)
-                {
-                  records.push_back(std::move(llarp::dns::SRVData::fromTuple(record)));
-                }
-              }
-              msg->AddSRVReply(records);
+              msg->AddSRVReply(introset.GetMatchingSRVRecords(addr.subdomain));
               reply(*msg);
             },
             2s);
@@ -511,20 +501,20 @@ namespace llarp
         reply(msg);
         return true;
       }
-      // TODO: SRV Record
       else if (msg.questions[0].qtype == dns::qTypeSRV)
       {
         llarp::service::Address addr;
 
         if (is_localhost_loki(msg))
         {
-          msg.AddNXReply();
+          msg.AddSRVReply(introSet().GetMatchingSRVRecords(msg.questions[0].Subdomains()));
           reply(msg);
           return true;
         }
         else if (addr.FromString(qname, ".loki"))
         {
-          llarp::LogWarn("SRV request for: ", qname);
+          llarp::LogDebug("SRV request for: ", qname);
+
           return ReplyToLokiSRVWhenReady(addr, std::make_shared<dns::Message>(msg));
         }
       }

llarp/service/endpoint.hpp

@@ -459,7 +459,6 @@ namespace llarp
       std::shared_ptr<IAuthPolicy> m_AuthPolicy;
       std::unordered_map<Address, AuthInfo, Address::Hash> m_RemoteAuthInfos;
 
-     private:
       void
       FlushRecvData();
 

llarp/service/intro_set.cpp

@@ -282,6 +282,22 @@ namespace llarp
       return GetNewestIntroExpiration() < now;
     }
 
+    std::vector<llarp::dns::SRVData>
+    IntroSet::GetMatchingSRVRecords(std::string_view service_proto) const
+    {
+      std::vector<llarp::dns::SRVData> records;
+
+      for (const auto& tuple : SRVs)
+      {
+        if (std::get<0>(tuple) == service_proto)
+        {
+          records.push_back(llarp::dns::SRVData::fromTuple(tuple));
+        }
+      }
+
+      return records;
+    }
+
     bool
     IntroSet::Verify(llarp_time_t now) const
     {

llarp/service/intro_set.hpp

@@ -58,6 +58,9 @@ namespace llarp
       bool
       IsExpired(llarp_time_t now) const;
 
+      std::vector<llarp::dns::SRVData>
+      GetMatchingSRVRecords(std::string_view service_proto) const;
+
       bool
       BEncode(llarp_buffer_t* buf) const;
 

test/dns/test_llarp_dns_dns.cpp

@@ -48,6 +48,64 @@ TEST_F(DNSLibTest, TestHasTLD)
   ASSERT_FALSE(question.HasTLD(tld));
 };
 
+TEST_F(DNSLibTest, TestIsLocalhost)
+{
+  llarp::dns::Question question;
+
+  question.qname = "localhost.loki.";
+  ASSERT_TRUE(question.IsLocalhost());
+  question.qname = "foo.localhost.loki.";
+  ASSERT_TRUE(question.IsLocalhost());
+  question.qname = "foo.bar.localhost.loki.";
+  ASSERT_TRUE(question.IsLocalhost());
+
+  question.qname = "something.loki.";
+  ASSERT_FALSE(question.IsLocalhost());
+  question.qname = "localhost.something.loki.";
+  ASSERT_FALSE(question.IsLocalhost());
+  question.qname = "notlocalhost.loki.";
+  ASSERT_FALSE(question.IsLocalhost());
+};
+
+TEST_F(DNSLibTest, TestGetSubdomains)
+{
+  llarp::dns::Question question;
+  std::string expected;
+
+  question.qname = "localhost.loki.";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = "foo.localhost.loki.";
+  expected = "foo";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = "foo.bar.localhost.loki.";
+  expected = "foo.bar";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  // not legal, but test it anyway
+  question.qname = ".localhost.loki.";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = ".loki.";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = "loki.";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = ".";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+
+  question.qname = "";
+  expected = "";
+  ASSERT_EQ(question.Subdomains(), expected);
+};
+
 TEST_F(DNSLibTest, TestPTR)
 {
   llarp::huint128_t ip = {0};