From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Wed, 29 Oct 2025 14:49:57 +0000 (+0100)
Subject: feat(protozero): Add a more generic function to extract Trace and Span ID from EDNS... 
X-Git-Tag: rec-5.4.0-alpha1~120^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=18b7258b5fda903f87acbf3a5747778d7bf22f1a;p=thirdparty%2Fpdns.git

feat(protozero): Add a more generic function to extract Trace and Span ID from EDNS option
---

diff --git a/pdns/protozero-trace.cc b/pdns/protozero-trace.cc
index 87639aecc8..e86f6da5e0 100644
--- a/pdns/protozero-trace.cc
+++ b/pdns/protozero-trace.cc
@@ -22,6 +22,7 @@
 
 #include "protozero-trace.hh"
 #include "base64.hh"
+#include "ednsoptions.hh"
 #include "misc.hh"
 #include <string>
 #include <variant>
@@ -557,25 +558,44 @@ void extractOTraceIDs(const EDNSOptionViewMap& map, pdns::trace::InitialSpanInfo
   // traceid gets set from edns options (if available and well-formed), otherwise random
   // parent_span_id gets set from edns options (if available and well-formed, otherwise it remains cleared (no parent))
   // span_id gets inited randomly
-  bool traceidset = false;
+  auto traceidset = extractOTraceIDs(map, EDNSOptionCode::OTTRACEIDS, span.trace_id, span.parent_span_id);
 
-  if (const auto& option = map.find(EDNSOptionCode::OTTRACEIDS); option != map.end()) {
+  if (!traceidset) {
+    span.trace_id.makeRandom();
+  }
+  // Empty parent span id indicated the client did not set one, thats fine
+  span.span_id.makeRandom();
+}
+
+/**
+ * @brief Extract the Trace and Span IDs from
+ *
+ * @param map an EDNSOptionViewMap where a TraceID option might be
+ * @param eoc the EDNS option code where the TraceID might be, OTTRACEIDS by default
+ * @param traceID will be set to the TraceID in the EDNS option, untouched otherwise
+ * @param spanID will be set to the SpanID in the EDNS options, untouched otherwise
+ * @return true if a traceid was found in the EDNS options
+ */
+bool extractOTraceIDs(const EDNSOptionViewMap& map, const EDNSOptionCode::EDNSOptionCodeEnum& eoc, pdns::trace::TraceID& traceID, pdns::trace::SpanID& spanID)
+{
+  EDNSOptionCode::EDNSOptionCodeEnum realEOC = eoc;
+  if (realEOC == 0) {
+    realEOC = EDNSOptionCode::OTTRACEIDS;
+  }
+  bool traceidset = false;
+  if (const auto& option = map.find(realEOC); option != map.end()) {
     const auto& value = option->second.values.at(0);
     const EDNSOTTraceRecordView data{reinterpret_cast<const uint8_t*>(value.content), value.size}; // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
     // 1 byte version, then tracid then optional spanid
     uint8_t version{};
     if (data.getVersion(version) && version == 0) {
-      if (data.getTraceID(span.trace_id)) {
+      if (data.getTraceID(traceID)) {
         traceidset = true;
       }
-      (void)data.getSpanID(span.parent_span_id);
+      (void)data.getSpanID(spanID);
     }
   }
-  if (!traceidset) {
-    span.trace_id.makeRandom();
-  }
-  // Empty parent span id indicated the client did not set one, thats fine
-  span.span_id.makeRandom();
+  return traceidset;
 }
 
 std::string SpanID::toLogString() const
diff --git a/pdns/protozero-trace.hh b/pdns/protozero-trace.hh
index d739c26a82..23039fa7bb 100644
--- a/pdns/protozero-trace.hh
+++ b/pdns/protozero-trace.hh
@@ -819,5 +819,6 @@ private:
 };
 
 void extractOTraceIDs(const EDNSOptionViewMap& map, pdns::trace::InitialSpanInfo& span);
+bool extractOTraceIDs(const EDNSOptionViewMap& map, const EDNSOptionCode::EDNSOptionCodeEnum& eoc, pdns::trace::TraceID& traceID, pdns::trace::SpanID& spanID);
 
 } // namespace pdns::trace