introduce peers registry on nodes

- TestPeerPromotionByTdOnBlock renamed and skipped for now test should pass iff
  if TD is updated based on an agreement
- senders register in AddBlock, flag records if they are coming from newblock
  message (and therefore advertise their TD with the block) or block message
  (TODO: latter are stored on the cache and updated by checkTD call;
  protocol should also call AddBlock on newblock messages by non-best peers)
- remove TD update from optional TD field in addBlock: this is no longer part of
  the eth protocol spec -> TODO: reflect in wiki
- only initialise peer map if at least two

blockpool/blockpool.go

@@ -132,6 +132,7 @@ type node struct {
 	block   *types.Block
 	hashBy  string
 	blockBy string
+	peers   map[string]bool
 	td      *big.Int
 }
 
@@ -396,6 +397,7 @@ func (self *BlockPool) AddBlockHashes(next func() (common.Hash, bool), peerId st
 		if entry := self.get(bestpeer.currentBlockHash); entry == nil {
 			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) head section starting from [%s] ", peerId, hex(bestpeer.currentBlockHash), hex(bestpeer.parentHash))
 			// if head block is not yet in the pool, create entry and start node list for section
+
 			node := &node{
 				hash:    bestpeer.currentBlockHash,
 				block:   bestpeer.currentBlock,
@@ -622,10 +624,14 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 	self.status.lock.Unlock()
 
 	entry := self.get(hash)
-
-	// a peer's current head block is appearing the first time
+	blockIsCurrentHead := false
 	sender.lock.Lock()
+	// a peer's current head block is appearing the first time
 	if hash == sender.currentBlockHash {
+		// this happens when block came in a newblock message but
+		// also if sent in a blockmsg (for instance, if we requested, only if we
+		// dont apply on blockrequests the restriction of flood control)
+		blockIsCurrentHead = true
 		if sender.currentBlock == nil {
 			plog.Debugf("AddBlock: add head block %s for peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
 			sender.setChainInfoFromBlock(block)
@@ -643,29 +649,10 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 			plog.DebugDetailf("AddBlock: head block %s for peer <%s> (head: %s) already known", hex(hash), peerId, hex(sender.currentBlockHash))
 			// signal to head section process
 		}
-		// self.wg.Add(1)
-		// go func() {
-		// 	timeout := time.After(1 * time.Second)
-		// select {
-		// 	case sender.currentBlockC <- block:
-		// 	case <-timeout:
-		// 	}
-		// 	self.wg.Done()
-		// }()
-
 	} else {
 
 		plog.DebugDetailf("AddBlock: block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
 
-		// update peer chain info if more recent than what we registered
-		if block.Td != nil && block.Td.Cmp(sender.td) > 0 {
-			sender.td = block.Td
-			sender.currentBlockHash = block.Hash()
-			sender.parentHash = block.ParentHash()
-			sender.currentBlock = block
-			sender.headSection = nil
-		}
-
 		/* @zelig !!!
 		   requested 5 hashes from both A & B. A responds sooner then B, process blocks. Close section.
 		   delayed B sends you block ... UNREQUESTED. Blocked
@@ -683,6 +670,8 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 	sender.lock.Unlock()
 
 	if entry == nil {
+		// FIXME: here check the cache find or create node -
+		// put peer as blockBy!
 		return
 	}
 
@@ -690,10 +679,22 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 	node.lock.Lock()
 	defer node.lock.Unlock()
 
+	// register peer on node as source
+	if node.peers == nil {
+		node.peers = make(map[string]bool)
+	}
+	FoundBlockCurrentHead, found := node.peers[sender.id]
+	if !found || FoundBlockCurrentHead {
+		// if found but not FoundBlockCurrentHead, then no update
+		// necessary (||)
+		node.peers[sender.id] = blockIsCurrentHead
+		// for those that are false, TD will update their head
+		// for those that are true, TD is checked !
+		// this is checked at the time of TD calculation in checkTD
+	}
 	// check if block already received
 	if node.block != nil {
 		plog.DebugDetailf("AddBlock: block %s from peer <%s> (head: %s) already sent by <%s> ", hex(hash), peerId, hex(sender.currentBlockHash), node.blockBy)
-		return
 	}
 
 	// check if block is already inserted in the blockchain
@@ -704,6 +705,8 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 
 	/*
 		@zelig needs discussing
+		Viktor: pow check can be delayed in a go routine and therefore cache
+		creation is not blocking
 			// validate block for PoW
 			if !self.verifyPoW(block) {
 				plog.Warnf("AddBlock: invalid PoW on block %s from peer  <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
@@ -718,8 +721,7 @@ func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
 	*/
 
 	node.block = block
-	node.blockBy = peerId
-	node.td = block.Td // optional field
+	// node.blockBy = peerId
 
 	self.status.lock.Lock()
 	self.status.values.Blocks++

blockpool/peers_test.go

@@ -144,7 +144,8 @@ func TestAddPeer(t *testing.T) {
 	blockPool.Stop()
 }
 
-func TestPeerPromotionByOptionalTdOnBlock(t *testing.T) {
+func TestPeerPromotionByTdOnBlock(t *testing.T) {
+	t.Skip()
 	test.LogInit()
 	_, blockPool, blockPoolTester := newTestBlockPool(t)
 	blockPoolTester.blockChain[0] = nil
@@ -168,13 +169,8 @@ func TestPeerPromotionByOptionalTdOnBlock(t *testing.T) {
 	best = peer2.AddPeer()
 	peer2.serveBlocks(3, 4)
 	peer2.serveBlockHashes(4, 3, 2, 1)
-	hashes := blockPoolTester.hashPool.IndexesToHashes([]int{2, 3})
-	peer1.waitBlocksRequests(3)
-	blockPool.AddBlock(&types.Block{
-		HeaderHash:       common.Hash(hashes[1]),
-		ParentHeaderHash: common.Hash(hashes[0]),
-		Td:               common.Big3,
-	}, "peer1")
+	// hashes := blockPoolTester.hashPool.IndexesToHashes([]int{2, 3})
+	peer1.serveBlocks(2, 3)
 
 	blockPool.RemovePeer("peer2")
 	if blockPool.peers.best.id != "peer1" {