From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Tue, 14 Mar 2017 14:31:01 +0000 (+0100)
Subject: document SyncRes::doCacheCheck in the dot file
X-Git-Tag: rec-4.1.0-alpha1~174^2~18
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=30e9bd9323e32f3bffdde02f71e6ffd2300723f0;p=pdns

document SyncRes::doCacheCheck in the dot file
---

diff --git a/pdns/recursordist/contrib/syncres.dot b/pdns/recursordist/contrib/syncres.dot
index e209a7f82..4ff5d547d 100644
--- a/pdns/recursordist/contrib/syncres.dot
+++ b/pdns/recursordist/contrib/syncres.dot
@@ -62,6 +62,32 @@ digraph {
     doResolve_doResolveAt -> doResolve_return_res [label="res >= 0"];
   }
 
+  subgraph cluster_doCacheCheck {
+    label="SyncRes::doCacheCheck(const DNSName &qname, const QType &qtype, vector<DNSRecord>&ret, unsigned int depth, int &res)";
+
+    doCacheCheck_return_false [label="return false", color=green];
+    "Did we have a positive or negative answer?" -> doCacheCheck_return_true [label=yes];
+    "Did we have a positive or negative answer?" -> doCacheCheck_return_false [label=no];
+    doCacheCheck_return_true [label="return true", color=green];
+
+    "Allocate return qname, qtype and qttl vars (RVARS) as qname, qtype" -> "Is the last label of qname negatively cached by root and is root-nx-trust enabled?";
+
+    "Is the last label of qname negatively cached by root and is root-nx-trust enabled?" -> "Set res to NXDOMAIN, set RVARS to to this label|SOA" [label=yes];
+    "Is the last label of qname negatively cached by root and is root-nx-trust enabled?" -> "Do we have a negative entry from an auth?" [label=no];
+    "Do we have a negative entry from an auth?" -> "Set RCODE (NOERROR or NXDOMAIN), set RVARS to (smaller) qname|SOA" [label=yes];
+    "Set RCODE (NOERROR or NXDOMAIN), set RVARS to (smaller) qname|SOA" -> "Add DNSSEC proof from cache";
+    "Set res to NXDOMAIN, set RVARS to to this label|SOA" -> "Do we have a positive for RVARS from an auth?";
+
+    "Do we have a negative entry from an auth?" -> "Do we have a positive for RVARS from an auth?" [label=no];
+
+    "Do we have a positive for RVARS from an auth?" -> "Did we have a positive or negative answer?" [label=no];
+    "Add DNSSEC proof from cache" -> "Do we have a positive for RVARS from an auth?";
+
+    "Do we have a positive for RVARS from an auth?" -> "Add positive answers to ret if not expired" [label=yes];
+    "Add positive answers to ret if not expired" -> "Add DNSSEC data to ret";
+    "Add DNSSEC data to ret" -> "Did we have a positive or negative answer?";
+  }
+
   subgraph cluster_getBestNSFromCache {
     label="SyncRes::getBestNSFromCache(const DNSName &qname, const QType& qtype, vector<DNSRecord>& bestns, bool* flawedNSSet, unsigned int depth, set<GetBestNSAnswer>& beenthere)\nFills the bestns vector with the 'closest' nameservers for qname\nflawedNSSet will be true if the NSSet has no glue.\nbeenthere contains the list of nameservers already visited during this recursion.";
 
diff --git a/pdns/syncres.cc b/pdns/syncres.cc
index fd6368094..e8ba86c10 100644
--- a/pdns/syncres.cc
+++ b/pdns/syncres.cc
@@ -796,6 +796,7 @@ bool SyncRes::doCacheCheck(const DNSName &qname, const QType &qtype, vector<DNSR
     prefix.append(depth, ' ');
   }
 
+  // sqname and sqtype are used contain 'higher' names if we have them (e.g. powerdns.com|SOA when we find a negative entry for doesnotexists.powerdns.com|A)
   DNSName sqname(qname);
   QType sqt(qtype);
   uint32_t sttl=0;