Merge bitcoin/bitcoin#29569: Rename CalculateHeadersWork to CalculateClaimedHeadersWork

eb7cc9f Rename CalculateHeadersWork to CalculateClaimedHeadersWork (Greg Sanders)

Pull request description:

  And clean up some comments. Confusion about what this is doing seems to be a running theme:

  bitcoin/bitcoin#29549 (comment)

  bitcoin/bitcoin#27278 (comment)

ACKs for top commit:
  achow101:
    ACK eb7cc9f
  pablomartin4btc:
    ACK eb7cc9f
  0xB10C:
    ACK eb7cc9f
  dergoegge:
    ACK eb7cc9f
  BrandonOdiwuor:
    ACK eb7cc9f

Tree-SHA512: 6ccbc5e417155516487bb220753d189b5341dec05366db88a3fa5b1932eace21fbfaf23408c639bb54b36169a8d0a7536a1ee5e63b4ce5a3b70f2ff8407b6e07

Author: achow101

src/net_processing.cpp

@@ -2690,8 +2690,8 @@ bool PeerManagerImpl::IsContinuationOfLowWorkHeadersSync(Peer& peer, CNode& pfro
 
 bool PeerManagerImpl::TryLowWorkHeadersSync(Peer& peer, CNode& pfrom, const CBlockIndex* chain_start_header, std::vector<CBlockHeader>& headers)
 {
-    // Calculate the total work on this chain.
-    arith_uint256 total_work = chain_start_header->nChainWork + CalculateHeadersWork(headers);
+    // Calculate the claimed total work on this chain.
+    arith_uint256 total_work = chain_start_header->nChainWork + CalculateClaimedHeadersWork(headers);
 
     // Our dynamic anti-DoS threshold (minimum work required on a headers chain
     // before we'll store it)
@@ -4424,7 +4424,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
                 MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), *peer);
             }
             return;
-        } else if (prev_block->nChainWork + CalculateHeadersWork({cmpctblock.header}) < GetAntiDoSWorkThreshold()) {
+        } else if (prev_block->nChainWork + CalculateClaimedHeadersWork({cmpctblock.header}) < GetAntiDoSWorkThreshold()) {
             // If we get a low-work header in a compact block, we can ignore it.
             LogPrint(BCLog::NET, "Ignoring low-work compact block from peer %d\n", pfrom.GetId());
             return;
@@ -4744,8 +4744,8 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             // cs_main in ProcessNewBlock is fine.
             mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true));
 
-            // Check work on this block against our anti-dos thresholds.
-            if (prev_block && prev_block->nChainWork + CalculateHeadersWork({pblock->GetBlockHeader()}) >= GetAntiDoSWorkThreshold()) {
+            // Check claimed work on this block against our anti-dos thresholds.
+            if (prev_block && prev_block->nChainWork + CalculateClaimedHeadersWork({pblock->GetBlockHeader()}) >= GetAntiDoSWorkThreshold()) {
                 min_pow_checked = true;
             }
         }

src/test/fuzz/headerssync.cpp

@@ -108,7 +108,7 @@ FUZZ_TARGET(headers_sync_state, .init = initialize_headers_sync_state_fuzz)
 
                     // If we get to redownloading, the presynced headers need
                     // to have the min amount of work on them.
-                    assert(CalculateHeadersWork(all_headers) >= min_work);
+                    assert(CalculateClaimedHeadersWork(all_headers) >= min_work);
                 }
             }
 

src/validation.cpp

@@ -3895,7 +3895,7 @@ bool IsBlockMutated(const CBlock& block, bool check_witness_root)
     return false;
 }
 
-arith_uint256 CalculateHeadersWork(const std::vector<CBlockHeader>& headers)
+arith_uint256 CalculateClaimedHeadersWork(const std::vector<CBlockHeader>& headers)
 {
     arith_uint256 total_work{0};
     for (const CBlockHeader& header : headers) {

src/validation.h

@@ -382,8 +382,8 @@ bool HasValidProofOfWork(const std::vector<CBlockHeader>& headers, const Consens
 /** Check if a block has been mutated (with respect to its merkle root and witness commitments). */
 bool IsBlockMutated(const CBlock& block, bool check_witness_root);
 
-/** Return the sum of the work on a given set of headers */
-arith_uint256 CalculateHeadersWork(const std::vector<CBlockHeader>& headers);
+/** Return the sum of the claimed work on a given set of headers. No verification of PoW is done. */
+arith_uint256 CalculateClaimedHeadersWork(const std::vector<CBlockHeader>& headers);
 
 enum class VerifyDBResult {
     SUCCESS,