From: Remi Gacogne <rgacogne-github@coredump.fr>
Date: Thu, 5 Nov 2015 09:47:39 +0000 (+0100)
Subject: Add a 'mustResolve' parameter to newServer()
X-Git-Tag: dnsdist-1.0.0-alpha1~210^2~10^2~1^2~2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a6e02424969145a706434c8b3336135ae7446140;p=pdns

Add a 'mustResolve' parameter to newServer()

The default is to consider any response with a rcode different from
Servfail as valid. Passing true to mustResolve requires a rcode different
from NXDomain, Servfail and Refused.
---

diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index 679b538eb..1ff48e75b 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -66,7 +66,7 @@ std::shared_ptr<DNSRule> makeRule(const luadnsrule_t& var)
 vector<std::function<void(void)>> setupLua(bool client, const std::string& config)
 {
   g_launchWork= new vector<std::function<void(void)>>();
-  typedef std::unordered_map<std::string, boost::variant<std::string, vector<pair<int, std::string> > > > newserver_t;
+  typedef std::unordered_map<std::string, boost::variant<bool, std::string, vector<pair<int, std::string> > > > newserver_t;
 
   g_lua.writeVariable("DNSAction", std::unordered_map<string,int>{
       {"Drop", (int)DNSAction::Action::Drop}, 
@@ -176,6 +176,10 @@ vector<std::function<void(void)>> setupLua(bool client, const std::string& confi
 			  ret->checkType=boost::get<string>(vars["checkType"]);
 			}
 
+			if(vars.count("mustResolve")) {
+			  ret->mustResolve=boost::get<bool>(vars["mustResolve"]);
+			}
+
 			if(g_launchWork) {
 			  g_launchWork->push_back([ret]() {
 			      ret->tid = move(thread(responderThread, ret));
diff --git a/pdns/dnsdist.cc b/pdns/dnsdist.cc
index c35281f9b..abc24eae6 100644
--- a/pdns/dnsdist.cc
+++ b/pdns/dnsdist.cc
@@ -214,8 +214,7 @@ bool operator<(const struct timespec&a, const struct timespec& b)
 }
 
 
-DownstreamState::DownstreamState(const ComboAddress& remote_):
-checkName("a.root-servers.net."), checkType(QType::A)
+DownstreamState::DownstreamState(const ComboAddress& remote_): checkName("a.root-servers.net."), checkType(QType::A), mustResolve(false)
 {
   remote = remote_;
   
@@ -557,7 +556,7 @@ catch(...)
 }
 
 
-bool upCheck(const ComboAddress& remote, const DNSName& checkName, const QType& checkType)
+bool upCheck(const ComboAddress& remote, const DNSName& checkName, const QType& checkType, bool mustResolve)
 try
 {
   vector<uint8_t> packet;
@@ -592,6 +591,8 @@ try
     return false;
   if (responseHeader.rcode == RCode::ServFail)
     return false;
+  if (mustResolve && (responseHeader.rcode == RCode::NXDomain || responseHeader.rcode == RCode::Refused))
+    return false;
 
   // XXX fixme do bunch of checking here etc 
   return true;
@@ -613,7 +614,7 @@ void* maintThread()
 
     for(auto& dss : g_dstates.getCopy()) { // this points to the actual shared_ptrs!
       if(dss->availability==DownstreamState::Availability::Auto) {
-	bool newState=upCheck(dss->remote, dss->checkName, dss->checkType);
+	bool newState=upCheck(dss->remote, dss->checkName, dss->checkType, dss->mustResolve);
 	if(newState != dss->upStatus) {
 	  warnlog("Marking downstream %s as '%s'", dss->getName(), newState ? "up" : "down");
 	}
@@ -1125,7 +1126,7 @@ try
 
   for(auto& dss : g_dstates.getCopy()) { // it is a copy, but the internal shared_ptrs are the real deal
     if(dss->availability==DownstreamState::Availability::Auto) {
-      bool newState=upCheck(dss->remote, dss->checkName, dss->checkType);
+      bool newState=upCheck(dss->remote, dss->checkName, dss->checkType, dss->mustResolve);
       warnlog("Marking downstream %s as '%s'", dss->remote.toStringWithPort(), newState ? "up" : "down");
       dss->upStatus = newState;
     }
diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index 271364bf3..7cbefe71d 100644
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -255,6 +255,7 @@ struct DownstreamState
   StopWatch sw;
   set<string> pools;
   enum class Availability { Up, Down, Auto} availability{Availability::Auto};
+  bool mustResolve;
   bool upStatus{false};
   bool isUp() const
   {