random.snode

llarp/dns/message.cpp

@@ -189,6 +189,30 @@ namespace llarp
       }
     }
 
+    void
+    Message::AddCNAMEReply(std::string name, uint32_t ttl)
+    {
+      if(questions.size())
+      {
+        hdr_fields |= (1 << 15);
+        const auto& question = questions[0];
+        answers.emplace_back();
+        auto& rec       = answers.back();
+        rec.rr_name     = question.qname;
+        rec.rr_type     = 5;
+        rec.rr_class    = 1;
+        rec.ttl         = ttl;
+        byte_t tmp[512] = {0};
+        auto buf        = llarp::StackBuffer< decltype(tmp) >(tmp);
+        if(EncodeName(&buf, name))
+        {
+          buf.sz = buf.cur - buf.base;
+          rec.rData.resize(buf.sz);
+          memcpy(rec.rData.data(), buf.base, buf.sz);
+        }
+      }
+    }
+
     void
     Message::AddMXReply(std::string name, uint16_t priority)
     {

llarp/dns/message.hpp

@@ -56,6 +56,9 @@ namespace llarp
       void
       AddMXReply(std::string name, uint16_t priority);
 
+      void
+      AddCNAMEReply(std::string name, uint32_t ttl);
+
       void
       AddINReply(llarp::huint32_t addr);
 

llarp/handlers/tun.cpp

@@ -200,8 +200,15 @@ namespace llarp
       {
         // forward dns
         llarp::service::Address addr;
-
+        if(qname == "random.snode" || qname == "random.snode.")
-        if(addr.FromString(qname, ".loki"))
+        {
+          RouterID random;
+          if(Router()->GetRandomGoodRouter(random))
+            msg.AddCNAMEReply(random.ToString(), 1);
+          else
+            msg.AddNXReply();
+        }
+        else if(addr.FromString(qname, ".loki"))
         {
           if(HasAddress(addr.data()))
           {
@@ -274,6 +281,9 @@ namespace llarp
         // always hook mx records
         if(msg.questions[0].qtype == 15)
           return true;
+        if(msg.questions[0].qname == "random.snode"
+           || msg.questions[0].qname == "random.snode.")
+          return true;
         // always hook .loki
         if(addr.FromString(msg.questions[0].qname, ".loki"))
           return true;

llarp/router.cpp

@@ -10,6 +10,7 @@
 #include <router.hpp>
 #include <rpc.hpp>
 #include <str.hpp>
+#include <crypto.hpp>
 
 #include <fstream>
 #include <cstdlib>
@@ -233,6 +234,19 @@ namespace llarp
         std::max(until, m_PersistingSessions[remote]);
   }
 
+  bool
+  Router::GetRandomGoodRouter(RouterID &router)
+  {
+    auto sz = nodedb->entries.size();
+    if(sz == 0)
+      return false;
+    auto itr = nodedb->entries.begin();
+    if(sz > 1)
+      std::advance(itr, randint() % sz);
+    router = itr->first;
+    return true;
+  }
+
   constexpr size_t MaxPendingSendQueueSize = 8;
 
   bool

llarp/router.hpp

@@ -199,6 +199,9 @@ namespace llarp
     bool
     InitOutboundLink();
 
+    bool
+    GetRandomGoodRouter(RouterID &r);
+
     /// initialize us as a service node
     /// return true on success
     bool

llarp/rpc.cpp

@@ -179,7 +179,7 @@ namespace llarp
 
     struct Handler : public ::abyss::httpd::IRPCHandler
     {
-        llarp::Router* router;
+      llarp::Router* router;
       Handler(::abyss::httpd::ConnImpl* conn, llarp::Router* r)
           : ::abyss::httpd::IRPCHandler(conn), router(r)
       {
@@ -273,7 +273,7 @@ namespace llarp
 
     struct ServerImpl
     {
-        llarp::Router* router;
+      llarp::Router* router;
       ReqHandlerImpl _handler;
 
       ServerImpl(llarp::Router* r) : router(r), _handler(r, 2000)