p2p: Add PeerManager method to count the amount of inbound/outbounds fanout peers

src/net_processing.cpp

@@ -503,6 +503,7 @@ public:
     std::vector<TxOrphanage::OrphanTxBase> GetOrphanTransactions() override EXCLUSIVE_LOCKS_REQUIRED(!m_tx_download_mutex);
     PeerManagerInfo GetInfo() const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
     void SendPings() override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
+    std::pair<size_t, size_t> GetFanoutPeersCount() override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
     void RelayTransaction(const uint256& txid, const uint256& wtxid) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
     void SetBestBlock(int height, std::chrono::seconds time) override
     {
@@ -2114,6 +2115,26 @@ void PeerManagerImpl::SendPings()
     for(auto& it : m_peer_map) it.second->m_ping_queued = true;
 }
 
+std::pair<size_t, size_t> PeerManagerImpl::GetFanoutPeersCount()
+{
+
+    size_t inbounds_fanout_tx_relay = 0, outbounds_fanout_tx_relay = 0;
+
+    if (m_txreconciliation) {
+        LOCK(m_peer_mutex);
+        for(const auto& [peer_id, peer] : m_peer_map) {
+            if (const auto tx_relay = peer->GetTxRelay()) {
+                const bool peer_relays_txs = WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs);
+                if (peer_relays_txs && !m_txreconciliation->IsPeerRegistered(peer_id)) {
+                    peer->m_is_inbound ? ++inbounds_fanout_tx_relay : ++outbounds_fanout_tx_relay;
+                }
+            }
+        }
+    }
+
+    return std::pair(inbounds_fanout_tx_relay, outbounds_fanout_tx_relay);
+}
+
 void PeerManagerImpl::RelayTransaction(const uint256& txid, const uint256& wtxid)
 {
     LOCK(m_peer_mutex);

src/net_processing.h

@@ -108,6 +108,9 @@ public:
     /** Relay transaction to all peers. */
     virtual void RelayTransaction(const uint256& txid, const uint256& wtxid) = 0;
 
+    /** Get the amount of inbounds (first) and outbounds fanout peers (second). */
+    virtual std::pair<size_t, size_t> GetFanoutPeersCount() = 0;
+
     /** Send ping message to all peers */
     virtual void SendPings() = 0;