[fuzz] TxOrphanage::SanityCheck accounting

src/test/fuzz/txdownloadman.cpp

@@ -285,6 +285,7 @@ static void CheckInvariants(const node::TxDownloadManagerImpl& txdownload_impl,
 
     // Orphanage usage should never exceed what is allowed
     Assert(orphanage.Size() <= max_orphan_count);
+    txdownload_impl.m_orphanage.SanityCheck();
 
     // We should never have more than the maximum in-flight requests out for a peer.
     for (NodeId peer = 0; peer < NUM_PEERS; ++peer) {
@@ -437,8 +438,8 @@ FUZZ_TARGET(txdownloadman_impl, .init = initialize)
         auto time_skip = fuzzed_data_provider.PickValueInArray(TIME_SKIPS);
         if (fuzzed_data_provider.ConsumeBool()) time_skip *= -1;
         time += time_skip;
-        CheckInvariants(txdownload_impl, max_orphan_count);
     }
+    CheckInvariants(txdownload_impl, max_orphan_count);
     // Disconnect everybody, check that all data structures are empty.
     for (NodeId nodeid = 0; nodeid < NUM_PEERS; ++nodeid) {
         txdownload_impl.DisconnectedPeer(nodeid);

src/test/fuzz/txorphan.cpp

@@ -204,6 +204,7 @@ FUZZ_TARGET(txorphan, .init = initialize_orphanage)
                 });
 
         }
+
         // Set tx as potential parent to be used for future GetChildren() calls.
         if (!ptx_potential_parent || fuzzed_data_provider.ConsumeBool()) {
             ptx_potential_parent = tx;
@@ -213,4 +214,5 @@ FUZZ_TARGET(txorphan, .init = initialize_orphanage)
         const bool get_tx_nonnull{orphanage.GetTx(tx->GetWitnessHash()) != nullptr};
         Assert(have_tx == get_tx_nonnull);
     }
+    orphanage.SanityCheck();
 }

src/txorphanage.cpp

@@ -321,3 +321,43 @@ std::vector<TxOrphanage::OrphanTxBase> TxOrphanage::GetOrphanTransactions() cons
     }
     return ret;
 }
+
+void TxOrphanage::SanityCheck() const
+{
+    // Check that cached m_total_announcements is correct
+    unsigned int counted_total_announcements{0};
+    // Check that m_total_orphan_usage is correct
+    unsigned int counted_total_usage{0};
+
+    // Check that cached PeerOrphanInfo::m_total_size is correct
+    std::map<NodeId, unsigned int> counted_size_per_peer;
+
+    for (const auto& [wtxid, orphan] : m_orphans) {
+        counted_total_announcements += orphan.announcers.size();
+        counted_total_usage += orphan.GetUsage();
+
+        Assume(!orphan.announcers.empty());
+        for (const auto& peer : orphan.announcers) {
+            auto& count_peer_entry = counted_size_per_peer.try_emplace(peer).first->second;
+            count_peer_entry += orphan.GetUsage();
+        }
+    }
+
+    Assume(m_total_announcements >= m_orphans.size());
+    Assume(counted_total_announcements == m_total_announcements);
+    Assume(counted_total_usage == m_total_orphan_usage);
+
+    // There must be an entry in m_peer_orphanage_info for each peer
+    // However, there may be m_peer_orphanage_info entries corresponding to peers for whom we
+    // previously had orphans but no longer do.
+    Assume(counted_size_per_peer.size() <= m_peer_orphanage_info.size());
+
+    for (const auto& [peerid, info] : m_peer_orphanage_info) {
+        auto it_counted = counted_size_per_peer.find(peerid);
+        if (it_counted == counted_size_per_peer.end()) {
+            Assume(info.m_total_usage == 0);
+        } else {
+            Assume(it_counted->second == info.m_total_usage);
+        }
+    }
+}

src/txorphanage.h

@@ -105,6 +105,10 @@ public:
         return peer_it == m_peer_orphanage_info.end() ? 0 : peer_it->second.m_total_usage;
     }
 
+    /** Check consistency between PeerOrphanInfo and m_orphans. Recalculate counters and ensure they
+     * match what is cached. */
+    void SanityCheck() const;
+
 protected:
     struct OrphanTx : public OrphanTxBase {
         size_t list_pos;