From bd97075e073ea10bc3d22f710a0ccdaaff2080a8 Mon Sep 17 00:00:00 2001
From: stasatdaglabs <39559713+stasatdaglabs@users.noreply.github.com>
Date: Thu, 24 Dec 2020 16:53:26 +0200
Subject: [PATCH] Remove the limit to the returned headers from
 buildMsgBlockHeaders (#1281)

* Remove the limit to the returned header hashes from buildMsgBlockHeaders.

* Build msgBlockHeaders in batches rather than all at once.
---
 .../blockrelay/handle_request_headers.go      | 48 +++++++------------
 .../blockrelay/handle_request_headers_test.go | 15 ------
 2 files changed, 16 insertions(+), 47 deletions(-)
 delete mode 100644 app/protocol/flows/blockrelay/handle_request_headers_test.go

diff --git a/app/protocol/flows/blockrelay/handle_request_headers.go b/app/protocol/flows/blockrelay/handle_request_headers.go
index 6600461d8..a512369b3 100644
--- a/app/protocol/flows/blockrelay/handle_request_headers.go
+++ b/app/protocol/flows/blockrelay/handle_request_headers.go
@@ -10,7 +10,6 @@ import (
 )
 
 const ibdBatchSize = router.DefaultMaxMessages
-const maxHeaders = appmessage.MaxInvPerMsg
 
 // RequestIBDBlocksContext is the interface for the context needed for the HandleRequestHeaders flow.
 type RequestIBDBlocksContext interface {
@@ -39,26 +38,35 @@ func (flow *handleRequestBlocksFlow) start() error {
 			return err
 		}
 
-		msgHeaders, err := flow.buildMsgBlockHeaders(lowHash, highHash)
+		blockHashes, err := flow.Domain().Consensus().GetHashesBetween(lowHash, highHash)
 		if err != nil {
 			return err
 		}
 
-		for offset := 0; offset < len(msgHeaders); offset += ibdBatchSize {
+		for offset := 0; offset < len(blockHashes); offset += ibdBatchSize {
 			end := offset + ibdBatchSize
-			if end > len(msgHeaders) {
-				end = len(msgHeaders)
+			if end > len(blockHashes) {
+				end = len(blockHashes)
 			}
 
-			blocksToSend := msgHeaders[offset:end]
-			err = flow.sendHeaders(blocksToSend)
+			blocksHashesToSend := blockHashes[offset:end]
+
+			msgBlockHeadersToSend := make([]*appmessage.MsgBlockHeader, len(blocksHashesToSend))
+			for i, blockHash := range blocksHashesToSend {
+				header, err := flow.Domain().Consensus().GetBlockHeader(blockHash)
+				if err != nil {
+					return err
+				}
+				msgBlockHeadersToSend[i] = appmessage.DomainBlockHeaderToBlockHeader(header)
+			}
+			err = flow.sendHeaders(msgBlockHeadersToSend)
 			if err != nil {
 				return nil
 			}
 
 			// Exit the loop and don't wait for the GetNextIBDBlocks message if the last batch was
 			// less than ibdBatchSize.
-			if len(blocksToSend) < ibdBatchSize {
+			if len(blocksHashesToSend) < ibdBatchSize {
 				break
 			}
 
@@ -91,30 +99,6 @@ func receiveRequestHeaders(incomingRoute *router.Route) (lowHash *externalapi.Do
 	return msgRequestIBDBlocks.LowHash, msgRequestIBDBlocks.HighHash, nil
 }
 
-func (flow *handleRequestBlocksFlow) buildMsgBlockHeaders(lowHash *externalapi.DomainHash,
-	highHash *externalapi.DomainHash) ([]*appmessage.MsgBlockHeader, error) {
-
-	blockHashes, err := flow.Domain().Consensus().GetHashesBetween(lowHash, highHash)
-	if err != nil {
-		return nil, err
-	}
-
-	if len(blockHashes) > maxHeaders {
-		blockHashes = blockHashes[:maxHeaders]
-	}
-
-	msgBlockHeaders := make([]*appmessage.MsgBlockHeader, len(blockHashes))
-	for i, blockHash := range blockHashes {
-		header, err := flow.Domain().Consensus().GetBlockHeader(blockHash)
-		if err != nil {
-			return nil, err
-		}
-		msgBlockHeaders[i] = appmessage.DomainBlockHeaderToBlockHeader(header)
-	}
-
-	return msgBlockHeaders, nil
-}
-
 func (flow *handleRequestBlocksFlow) sendHeaders(headers []*appmessage.MsgBlockHeader) error {
 	for _, msgBlockHeader := range headers {
 		err := flow.outgoingRoute.Enqueue(msgBlockHeader)
diff --git a/app/protocol/flows/blockrelay/handle_request_headers_test.go b/app/protocol/flows/blockrelay/handle_request_headers_test.go
deleted file mode 100644
index 704cad76b..000000000
--- a/app/protocol/flows/blockrelay/handle_request_headers_test.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package blockrelay
-
-import (
-	"github.com/kaspanet/kaspad/domain/consensus/utils/testutils"
-	"github.com/kaspanet/kaspad/domain/dagconfig"
-	"testing"
-)
-
-func TestMaxHeaders(t *testing.T) {
-	testutils.ForAllNets(t, false, func(t *testing.T, params *dagconfig.Params) {
-		if params.FinalityDepth() > maxHeaders {
-			t.Errorf("FinalityDepth() in %s should be lower or equal to appmessage.MaxInvPerMsg", params.Name)
-		}
-	})
-}