From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 7 Jun 2021 14:12:18 +0000 (+0200)
Subject: dnsdist: Implement 'tcpOnly' backends
X-Git-Tag: dnsdist-1.7.0-alpha1~45^2~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6e90096c29b6a5bd087c53f81542a4b5429fe99d;p=thirdparty%2Fpdns.git

dnsdist: Implement 'tcpOnly' backends
---

diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index fddb268427..989d6bab28 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -499,6 +499,10 @@ static void setupLuaConfig(LuaContext& luaCtx, bool client, bool configCheck)
         }
       }
 
+      if (vars.count("tcpOnly")) {
+        ret->d_tcpOnly = boost::get<bool>(vars.at("tcpOnly"));
+      }
+
       if (vars.count("tls")) {
         TLSContextParameters tlsParams;
         std::string ciphers;
diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index 2d394ca5de..85fa96ea2e 100644
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -739,6 +739,7 @@ struct DownstreamState
   bool ipBindAddrNoPort{true};
   bool reconnectOnUp{false};
   bool d_tcpCheck{false};
+  bool d_tcpOnly{false};
 
   bool isUp() const
   {
@@ -814,12 +815,12 @@ struct DownstreamState
 
   bool doHealthcheckOverTCP() const
   {
-    return d_tcpCheck || d_tlsCtx != nullptr;
+    return d_tcpOnly || d_tcpCheck || d_tlsCtx != nullptr;
   }
 
   bool isTCPOnly() const
   {
-    return d_tlsCtx != nullptr;
+    return d_tcpOnly || d_tlsCtx != nullptr;
   }
 
 private:
diff --git a/pdns/dnsdistdist/docs/reference/config.rst b/pdns/dnsdistdist/docs/reference/config.rst
index 29913fa6d6..cccf46a17f 100644
--- a/pdns/dnsdistdist/docs/reference/config.rst
+++ b/pdns/dnsdistdist/docs/reference/config.rst
@@ -488,6 +488,9 @@ Servers
   .. versionchanged:: 1.6.0
     Added ``maxInFlight`` to server_table.
 
+  .. versionchanged:: 1.7.0
+    Added ``tcpOnly`` to server_table.
+
   Add a new backend server. Call this function with either a string::
 
     newServer(
@@ -533,7 +536,8 @@ Servers
       rise=NUM,              -- Require NUM consecutive successful checks before declaring the backend up, default: 1
       useProxyProtocol=BOOL, -- Add a proxy protocol header to the query, passing along the client's IP address and port along with the original destination address and port. Default is disabled.
       reconnectOnUp=BOOL,    -- Close and reopen the sockets when a server transits from Down to Up. This helps when an interface is missing when dnsdist is started. Default is disabled.
-      maxInFlight            -- Maximum number of in-flight queries. The default is 0, which disables out-of-order processing. It should only be enabled if the backend does support out-of-order processing. As of 1.6.0, out-of-order processing needs to be enabled on the frontend as well, via :func:`addLocal` and/or :func:`addTLSLocal`. Note that out-of-order is always enabled on DoH frontends.
+      maxInFlight=NUM,       -- Maximum number of in-flight queries. The default is 0, which disables out-of-order processing. It should only be enabled if the backend does support out-of-order processing. As of 1.6.0, out-of-order processing needs to be enabled on the frontend as well, via :func:`addLocal` and/or :func:`addTLSLocal`. Note that out-of-order is always enabled on DoH frontends.
+      tcpOnly=BOOL           -- Always forward queries to that backend over TCP, never over UDP. Defaut is false.
     })
 
   :param str server_string: A simple IP:PORT string.