Bug 1652655 - P1: Sort HTTPSSVC records, r=dragana,necko-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D85121

netwerk/dns/HTTPSSVC.h

@@ -82,6 +82,9 @@ struct SVCB {
            mSvcDomainName == aOther.mSvcDomainName &&
            mSvcFieldValue == aOther.mSvcFieldValue;
   }
+  bool operator<(const SVCB& aOther) const {
+    return mSvcFieldPriority < aOther.mSvcFieldPriority;
+  }
   uint16_t mSvcFieldPriority = 0;
   nsCString mSvcDomainName;
   CopyableTArray<SvcFieldValue> mSvcFieldValue;

netwerk/dns/TRR.cpp

@@ -1197,6 +1197,16 @@ nsresult TRR::DohDecode(nsCString& aHost) {
     LOG(("TRR: No entries were stored!\n"));
     return NS_ERROR_FAILURE;
   }
+
+  // https://tools.ietf.org/html/draft-ietf-dnsop-svcb-httpssvc-03#page-14
+  // If one or more SVCB records of ServiceForm SvcRecordType are returned for
+  // HOST, clients should select the highest-priority option with acceptable
+  // parameters.
+  if (mResult.is<TypeRecordHTTPSSVC>()) {
+    auto& results = mResult.as<TypeRecordHTTPSSVC>();
+    results.Sort();
+  }
+
   return NS_OK;
 }