Add new (unused) limits for cluster size/count

diff --git a/src/init.cpp b/src/init.cpp
index dadd56d2..73222961 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -641,6 +641,8 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
     argsman.AddArg("-limitdescendantcount=<n>", strprintf("Do not accept transactions if any ancestor would have <n> or more in-mempool descendants (default: %u)", DEFAULT_DESCENDANT_LIMIT), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-limitdescendantsize=<n>", strprintf("Do not accept transactions if any ancestor would have more than <n> kilobytes of in-mempool descendants (default: %u).", DEFAULT_DESCENDANT_SIZE_LIMIT_KVB), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-test=<option>", "Pass a test-only option. Options include : " + Join(TEST_OPTIONS_DOC, ", ") + ".", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
+    argsman.AddArg("-limitclustercount=<n>", strprintf("Do not accept transactions into mempool which are directly or indirectly connected to <n> or more other unconfirmed transactions (default: %u, maximum: %u)", DEFAULT_CLUSTER_LIMIT, MAX_CLUSTER_COUNT_LIMIT), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
+    argsman.AddArg("-limitclustersize=<n>", strprintf("Do not accept transactions whose virtual size with all in-mempool connected transactions exceeds <n> kilobytes (default: %u)", DEFAULT_CLUSTER_SIZE_LIMIT_KVB), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-capturemessages", "Capture all P2P messages to disk", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-mocktime=<n>", "Replace actual time with " + UNIX_EPOCH_TIME + " (default: 0)", ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-maxsigcachesize=<n>", strprintf("Limit sum of signature cache and script execution cache sizes to <n> MiB (default: %u)", DEFAULT_VALIDATION_CACHE_BYTES >> 20), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
diff --git a/src/kernel/mempool_limits.h b/src/kernel/mempool_limits.h
index 8d4495c3..cbca1790 100644
--- a/src/kernel/mempool_limits.h
+++ b/src/kernel/mempool_limits.h
@@ -16,6 +16,10 @@ namespace kernel {
  * Most of the time, this struct should be referenced as CTxMemPool::Limits.
  */
 struct MemPoolLimits {
+    //! The maximum number of transactions in a cluster
+    unsigned cluster_count{DEFAULT_CLUSTER_LIMIT};
+    //! The maximum allowed size in virtual bytes of a cluster.
+    int64_t cluster_size_vbytes{DEFAULT_CLUSTER_SIZE_LIMIT_KVB * 1'000};
     //! The maximum allowed number of transactions in a package including the entry and its ancestors.
     int64_t ancestor_count{DEFAULT_ANCESTOR_LIMIT};
     //! The maximum allowed size in virtual bytes of an entry and its ancestors within a package.
@@ -31,7 +35,7 @@ struct MemPoolLimits {
     static constexpr MemPoolLimits NoLimits()
     {
         int64_t no_limit{std::numeric_limits<int64_t>::max()};
-        return {no_limit, no_limit, no_limit, no_limit};
+        return {std::numeric_limits<unsigned>::max(), no_limit, no_limit, no_limit, no_limit, no_limit};
     }
 };
 } // namespace kernel
diff --git a/src/node/mempool_args.cpp b/src/node/mempool_args.cpp
index abbe97d9..93b897d5 100644
--- a/src/node/mempool_args.cpp
+++ b/src/node/mempool_args.cpp
@@ -15,6 +15,7 @@
 #include <policy/feerate.h>
 #include <policy/policy.h>
 #include <tinyformat.h>
+#include <txgraph.h>
 #include <util/moneystr.h>
 #include <util/translation.h>
 
@@ -31,6 +32,10 @@ static constexpr int MAX_32BIT_MEMPOOL_MB{500};
 namespace {
 void ApplyArgsManOptions(const ArgsManager& argsman, MemPoolLimits& mempool_limits)
 {
+    mempool_limits.cluster_count = argsman.GetIntArg("-limitclustercount", mempool_limits.cluster_count);
+
+    if (auto vkb = argsman.GetIntArg("-limitclustersize")) mempool_limits.cluster_size_vbytes = *vkb * 1'000;
+
     mempool_limits.ancestor_count = argsman.GetIntArg("-limitancestorcount", mempool_limits.ancestor_count);
 
     if (auto vkb = argsman.GetIntArg("-limitancestorsize")) mempool_limits.ancestor_size_vbytes = *vkb * 1'000;
@@ -106,5 +111,9 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& argsman, const CChainP
 
     ApplyArgsManOptions(argsman, mempool_opts.limits);
 
+    if (mempool_opts.limits.cluster_count > MAX_CLUSTER_COUNT_LIMIT) {
+        return util::Error{Untranslated(strprintf("limitclustercount must be less than or equal to %d", MAX_CLUSTER_COUNT_LIMIT))};
+    }
+
     return {};
 }
diff --git a/src/policy/policy.h b/src/policy/policy.h
index 0e4314ea..2a15f29c 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -65,6 +65,10 @@ static constexpr unsigned int MAX_STANDARD_SCRIPTSIG_SIZE{1650};
 static constexpr unsigned int DUST_RELAY_TX_FEE{3000};
 /** Default for -minrelaytxfee, minimum relay fee for transactions */
 static constexpr unsigned int DEFAULT_MIN_RELAY_TX_FEE{100};
+/** Maximum number of transactions per cluster (default) */
+static constexpr unsigned int DEFAULT_CLUSTER_LIMIT{64};
+/** Maximum size of cluster in virtual kilobytes */
+static constexpr unsigned int DEFAULT_CLUSTER_SIZE_LIMIT_KVB{101};
 /** Default for -limitancestorcount, max number of in-mempool ancestors */
 static constexpr unsigned int DEFAULT_ANCESTOR_LIMIT{25};
 /** Default for -limitancestorsize, maximum kilobytes of tx + all in-mempool ancestors */