Merge #12603: [docs] PeerLogicValidation interface

b7cd08b71 Add documentation to PeerLogicValidation interface and related functions (James O'Beirne)

Pull request description:

  Adds docs for PeerLogicValidation's public interface and two related functions.

Tree-SHA512: b4c2f47e9baa9396d2b6faf3792e46b371c50cd91b9ac890f263f4d14eb24a71e7b40ceb4cbb41e254f5008eff357f417b842618e7ebece9039802ab2a5dd728

src/net_processing.cpp

@@ -544,6 +544,12 @@ void UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) EXCLUSIVE_LOCKS
     }
 }
 
+/**
+ * When a peer sends us a valid block, instruct it to announce blocks to us
+ * using CMPCTBLOCK if possible by adding its nodeid to the end of
+ * lNodesAnnouncingHeaderAndIDs, and keeping that list under a certain size by
+ * removing the first element if necessary.
+ */
 void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid, CConnman* connman)
 {
     AssertLockHeld(cs_main);
@@ -1109,6 +1115,10 @@ PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn, CScheduler &schedu
     scheduler.scheduleEvery(std::bind(&PeerLogicValidation::CheckForStaleTipAndEvictPeers, this, consensusParams), EXTRA_PEER_CHECK_INTERVAL * 1000);
 }
 
+/**
+ * Evict orphan txn pool entries (EraseOrphanTx) based on a newly connected
+ * block. Also save the time of the last tip update.
+ */
 void PeerLogicValidation::BlockConnected(const std::shared_ptr<const CBlock>& pblock, const CBlockIndex* pindex, const std::vector<CTransactionRef>& vtxConflicted) {
     LOCK2(cs_main, g_cs_orphans);
 
@@ -1139,7 +1149,7 @@ void PeerLogicValidation::BlockConnected(const std::shared_ptr<const CBlock>& pb
         }
     }
 
-    // Erase orphan transactions include or precluded by this block
+    // Erase orphan transactions included or precluded by this block
     if (vOrphanErase.size()) {
         int nErased = 0;
         for (uint256 &orphanHash : vOrphanErase) {
@@ -1162,6 +1172,10 @@ static std::shared_ptr<const CBlock> most_recent_block GUARDED_BY(cs_most_recent
 static std::shared_ptr<const CBlockHeaderAndShortTxIDs> most_recent_compact_block GUARDED_BY(cs_most_recent_block);
 static uint256 most_recent_block_hash GUARDED_BY(cs_most_recent_block);
 
+/**
+ * Maintain state about the best-seen block and fast-announce a compact block
+ * to compatible peers.
+ */
 void PeerLogicValidation::NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& pblock) {
     std::shared_ptr<const CBlockHeaderAndShortTxIDs> pcmpctblock = std::make_shared<const CBlockHeaderAndShortTxIDs> (*pblock);
     const CNetMsgMaker msgMaker(PROTOCOL_VERSION);
@@ -1202,6 +1216,10 @@ void PeerLogicValidation::NewPoWValidBlock(const CBlockIndex *pindex, const std:
     });
 }
 
+/**
+ * Update our best height and announce any block hashes which weren't previously
+ * in chainActive to our peers.
+ */
 void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) {
     const int nNewHeight = pindexNew->nHeight;
     connman->SetBestHeight(nNewHeight);
@@ -1235,6 +1253,10 @@ void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CB
     nTimeBestReceived = GetTime();
 }
 
+/**
+ * Handle invalid block rejection and consequent peer banning, maintain which
+ * peers announce compact blocks.
+ */
 void PeerLogicValidation::BlockChecked(const CBlock& block, const CValidationState& state) {
     LOCK(cs_main);
 

src/net_processing.h

@@ -28,13 +28,26 @@ private:
 public:
     explicit PeerLogicValidation(CConnman* connmanIn, CScheduler &scheduler, bool enable_bip61);
 
+    /**
+     * Overridden from CValidationInterface.
+     */
     void BlockConnected(const std::shared_ptr<const CBlock>& pblock, const CBlockIndex* pindexConnected, const std::vector<CTransactionRef>& vtxConflicted) override;
+    /**
+     * Overridden from CValidationInterface.
+     */
     void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) override;
+    /**
+     * Overridden from CValidationInterface.
+     */
     void BlockChecked(const CBlock& block, const CValidationState& state) override;
+    /**
+     * Overridden from CValidationInterface.
+     */
     void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& pblock) override;
 
-
+    /** Initialize a peer by adding it to mapNodeState and pushing a message requesting its version */
     void InitializeNode(CNode* pnode) override;
+    /** Handle removal of a peer by updating various state and removing it from mapNodeState */
     void FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTime) override;
     /** Process protocol messages received from a given node */
     bool ProcessMessages(CNode* pfrom, std::atomic<bool>& interrupt, bool &fRetDidWork) override;
@@ -47,8 +60,11 @@ public:
     */
     bool SendMessages(CNode* pto, std::atomic<bool>& interrupt) override;
 
+    /** Consider evicting an outbound peer based on the amount of time they've been behind our tip */
     void ConsiderEviction(CNode *pto, int64_t time_in_seconds);
+    /** Evict extra outbound peers. If we think our tip may be stale, connect to an extra outbound */
     void CheckForStaleTipAndEvictPeers(const Consensus::Params &consensusParams);
+    /** If we have extra outbound peers, try to disconnect the one with the oldest block announcement */
     void EvictExtraOutboundPeers(int64_t time_in_seconds) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 private: