td update from node

- reorg and simplify AddBlock
- introduce nodeCache
- TestPeerPromotionByTdOnBlock unskipped and passes
- move switchC/idleC channel creation around: solves deadlock (now respects the contract with section process: either can activate or complete at any one time)

4 files changed, 148 insertions, 139 deletions

diff --git a/blockpool/blockpool.go b/blockpool/blockpool.go
index f442259e0..3ed2e92c7 100644
--- a/blockpool/blockpool.go
+++ b/blockpool/blockpool.go
@@ -169,6 +169,9 @@ type BlockPool struct {
 	// alloc-easy pool of hash slices
 	hashSlicePool chan []common.Hash
 
+	nodeCache     map[common.Hash]*node
+	nodeCacheLock sync.RWMutex
+
 	// waitgroup is used in tests to wait for result-critical routines
 	// as well as in determining idle / syncing status
 	wg      sync.WaitGroup //
@@ -210,6 +213,7 @@ func (self *BlockPool) Start() {
 	self.Config.init()
 
 	self.hashSlicePool = make(chan []common.Hash, 150)
+	self.nodeCache = make(map[common.Hash]*node)
 	self.status = newStatus()
 	self.quit = make(chan bool)
 	self.pool = make(map[common.Hash]*entry)
@@ -615,127 +619,104 @@ LOOP:
 	If the block received is the head block of the current best peer, signal it to the head section process
 */
 func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
-	hash := block.Hash()
-
-	sender, _ := self.peers.getPeer(peerId)
-	if sender == nil {
-		return
-	}
 
 	self.status.lock.Lock()
 	self.status.activePeers[peerId]++
 	self.status.lock.Unlock()
 
-	entry := self.get(hash)
-	blockIsCurrentHead := false
-	sender.lock.RLock()
-	currentBlockHash := sender.currentBlockHash
-	currentBlock := sender.currentBlock
-	currentBlockC := sender.currentBlockC
-	switchC := sender.switchC
-	sender.lock.RUnlock()
-
-	// a peer's current head block is appearing the first time
-	if hash == 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 currentBlock == nil {
-			sender.lock.Lock()
-			sender.setChainInfoFromBlock(block)
-			sender.lock.Unlock()
-
-			self.status.lock.Lock()
-			self.status.values.BlockHashes++
-			self.status.values.Blocks++
-			self.status.values.BlocksInPool++
-			self.status.lock.Unlock()
-			// signal to head section process
-			select {
-			case currentBlockC <- block:
-			case <-switchC:
-			}
-		} else {
-			plog.DebugDetailf("AddBlock: head block %s for peer <%s> (head: %s) already known", hex(hash), peerId, hex(currentBlockHash))
-		}
-	} else {
-
-		plog.DebugDetailf("AddBlock: block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(currentBlockHash))
-
-		/* @zelig !!!
-		   requested 5 hashes from both A & B. A responds sooner then B, process blocks. Close section.
-		   delayed B sends you block ... UNREQUESTED. Blocked
-		     if entry == nil {
-		       plog.DebugDetailf("AddBlock: unrequested block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
-		       sender.addError(ErrUnrequestedBlock, "%x", hash)
-
-		       self.status.lock.Lock()
-		       self.status.badPeers[peerId]++
-		       self.status.lock.Unlock()
-		       return
-		     }
-		*/
-	}
+	hash := block.Hash()
 
-	if entry == nil {
-		// FIXME: here check the cache find or create node -
-		// put peer as blockBy!
+	// check if block is already inserted in the blockchain
+	if self.hasBlock(hash) {
 		return
 	}
 
-	node := entry.node
-	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)
-	}
-
-	// check if block is already inserted in the blockchain
-	if self.hasBlock(hash) {
-		plog.DebugDetailf("AddBlock: block %s from peer <%s> (head: %s) already in the blockchain", hex(hash), peerId, hex(sender.currentBlockHash))
+	sender, _ := self.peers.getPeer(peerId)
+	if sender == nil {
 		return
 	}
+	tdFromCurrentHead, currentBlockHash := sender.setChainInfoFromBlock(block)
 
-	/*
-		@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))
-				sender.addError(ErrInvalidPoW, "%x", hash)
+	entry := self.get(hash)
 
-				self.status.lock.Lock()
-				self.status.badPeers[peerId]++
-				self.status.lock.Unlock()
+	/* @zelig !!!
+	   requested 5 hashes from both A & B. A responds sooner then B, process blocks. Close section.
+	   delayed B sends you block ... UNREQUESTED. Blocked
+	     if entry == nil {
+	       plog.DebugDetailf("AddBlock: unrequested block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
+	       sender.addError(ErrUnrequestedBlock, "%x", hash)
+
+	       self.status.lock.Lock()
+	       self.status.badPeers[peerId]++
+	       self.status.lock.Unlock()
+	       return
+	     }
+	*/
 
-				return
+	var bnode *node
+	if entry == nil {
+		self.nodeCacheLock.Lock()
+		bnode, _ = self.nodeCache[hash]
+		if bnode == nil {
+			bnode = &node{
+				hash:    currentBlockHash,
+				block:   block,
+				hashBy:  peerId,
+				blockBy: peerId,
+				td:      tdFromCurrentHead,
 			}
-	*/
+			self.nodeCache[hash] = bnode
+		}
+		self.nodeCacheLock.Unlock()
+	} else {
+		bnode = entry.node
+	}
 
-	node.block = block
-	node.blockBy = peerId
+	bnode.lock.Lock()
+	defer bnode.lock.Unlock()
 
-	self.status.lock.Lock()
-	self.status.values.Blocks++
-	self.status.values.BlocksInPool++
-	self.status.lock.Unlock()
+	// check if block already received
+	if bnode.block != nil {
+		plog.DebugDetailf("AddBlock: block %s from peer <%s> (head: %s) already sent by <%s> ", hex(hash), peerId, hex(sender.currentBlockHash), bnode.blockBy)
+		// register peer on node as source
+		if bnode.peers == nil {
+			bnode.peers = make(map[string]bool)
+		}
+		foundBlockCurrentHead, found := bnode.peers[sender.id]
+		if !found || foundBlockCurrentHead {
+			// if found but not FoundBlockCurrentHead, then no update
+			// necessary (||)
+			bnode.peers[sender.id] = (currentBlockHash == hash)
+			// 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
+		}
+		sender.setChainInfoFromNode(bnode)
+	} else {
+		/*
+			@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))
+					sender.addError(ErrInvalidPoW, "%x", hash)
+
+					self.status.lock.Lock()
+					self.status.badPeers[peerId]++
+					self.status.lock.Unlock()
+
+					return
+				}
+		*/
+		bnode.block = block
+		bnode.blockBy = peerId
+		bnode.td = tdFromCurrentHead
+		self.status.lock.Lock()
+		self.status.values.Blocks++
+		self.status.values.BlocksInPool++
+		self.status.lock.Unlock()
+	}
 
 }
 
diff --git a/blockpool/errors_test.go b/blockpool/errors_test.go
index c9bf79a23..0fbf94d7d 100644
--- a/blockpool/errors_test.go
+++ b/blockpool/errors_test.go
@@ -128,7 +128,7 @@ func TestErrInsufficientChainInfo(t *testing.T) {
 }
 
 func TestIncorrectTD(t *testing.T) {
-	t.Skip() // td not tested atm
+	t.Skip("skipping TD check until network is healthy")
 	test.LogInit()
 	_, blockPool, blockPoolTester := newTestBlockPool(t)
 	blockPoolTester.blockChain[0] = nil
diff --git a/blockpool/peers.go b/blockpool/peers.go
index e5d6a16d6..90dc5daef 100644
--- a/blockpool/peers.go
+++ b/blockpool/peers.go
@@ -18,6 +18,7 @@ type peer struct {
 
 	// last known blockchain status
 	td               *big.Int
+	tdAdvertised     bool
 	currentBlockHash common.Hash
 	currentBlock     *types.Block
 	parentHash       common.Hash
@@ -135,21 +136,52 @@ func (self *peer) addError(code int, format string, params ...interface{}) {
 }
 
 // caller must hold peer lock
-func (self *peer) setChainInfo(td *big.Int, c common.Hash) {
-	self.td = td
-	self.currentBlockHash = c
-	self.currentBlock = nil
-	self.parentHash = common.Hash{}
-	self.headSection = nil
+func (self *peer) setChainInfo(td *big.Int, currentBlockHash common.Hash) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	if self.currentBlockHash != currentBlockHash {
+		previousBlockHash := self.currentBlockHash
+		plog.Debugf("addPeer: Update peer <%s> with td %v and current block %s (was %v)", self.id, td, hex(currentBlockHash), hex(previousBlockHash))
+		self.td = td
+		self.currentBlockHash = currentBlockHash
+		self.currentBlock = nil
+		self.parentHash = common.Hash{}
+		self.headSection = nil
+	}
+	self.tdAdvertised = true
 }
 
-// caller must hold peer lock
-func (self *peer) setChainInfoFromBlock(block *types.Block) {
-	// use the optional TD to update peer td, this helps second best peer selection
+func (self *peer) setChainInfoFromBlock(block *types.Block) (td *big.Int, currentBlockHash common.Hash) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	hash := block.Hash()
+	// 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)
+	currentBlockHash = self.currentBlockHash
+	if currentBlockHash == hash && self.currentBlock == nil {
+		// signal to head section process
+		plog.DebugDetailf("AddBlock: head block %s for peer <%s> (head: %s) received\n", hex(hash), self.id, hex(currentBlockHash))
+		select {
+		case self.currentBlockC <- block:
+		case <-self.switchC:
+		}
+		return self.td, currentBlockHash
+	} else {
+		plog.DebugDetailf("AddBlock: head block %s for peer <%s> (head: %s) already known", hex(hash), self.id, hex(currentBlockHash))
+		return nil, currentBlockHash
+	}
+}
+
+// this will use the TD given by the first peer to update peer td, this helps second best peer selection
+// :FIXME: node
+func (self *peer) setChainInfoFromNode(n *node) {
 	// in case best peer is lost
-	if block.Td != nil && block.Td.Cmp(self.td) > 0 {
-		plog.DebugDetailf("setChainInfoFromBlock: update <%s> - head: %v->%v - TD: %v->%v", self.id, hex(self.currentBlockHash), hex(block.Hash()), self.td, block.Td)
-		self.td = block.Td
+	block := n.block
+	hash := block.Hash()
+	if n.td != nil && n.td.Cmp(self.td) > 0 {
+		plog.DebugDetailf("AddBlock: update peer <%s> - head: %v->%v - TD: %v->%v", self.id, hex(self.currentBlockHash), hex(hash), self.td, n.td)
+		self.td = n.td
 		self.currentBlockHash = block.Hash()
 		self.parentHash = block.ParentHash()
 		self.currentBlock = block
@@ -218,17 +250,11 @@ func (self *peers) addPeer(
 	if found {
 		// when called on an already connected peer, it means a newBlockMsg is received
 		// peer head info is updated
-		p.lock.Lock()
-		if p.currentBlockHash != currentBlockHash {
-			previousBlockHash = p.currentBlockHash
-			plog.Debugf("addPeer: Update peer <%s> with td %v and current block %s (was %v)", id, td, hex(currentBlockHash), hex(previousBlockHash))
-			p.setChainInfo(td, currentBlockHash)
-
-			self.status.lock.Lock()
-			self.status.values.NewBlocks++
-			self.status.lock.Unlock()
-		}
-		p.lock.Unlock()
+		p.setChainInfo(td, currentBlockHash)
+		// FIXME: only count the same block once
+		self.status.lock.Lock()
+		self.status.values.NewBlocks++
+		self.status.lock.Unlock()
 	} else {
 		p = self.newPeer(td, currentBlockHash, id, requestBlockHashes, requestBlocks, peerError)
 
@@ -333,8 +359,8 @@ func (self *BlockPool) switchPeer(oldp, newp *peer) {
 		close(oldp.switchC)
 	}
 	if newp != nil {
-		newp.idleC = make(chan bool)
-		newp.switchC = make(chan bool)
+		// newp.idleC = make(chan bool)
+		// newp.switchC = make(chan bool)
 		// if new best peer has no head section yet, create it and run it
 		// otherwise head section is an element of peer.sections
 		if newp.headSection == nil {
@@ -354,6 +380,9 @@ func (self *BlockPool) switchPeer(oldp, newp *peer) {
 				}
 			}()
 
+		} else {
+			newp.idleC = make(chan bool)
+			newp.switchC = make(chan bool)
 		}
 
 		var connected = make(map[common.Hash]*section)
@@ -528,10 +557,12 @@ func (self *peer) getBlockHashes() bool {
 // main loop for head section process
 func (self *peer) run() {
 
-	self.lock.RLock()
+	self.lock.Lock()
+	self.switchC = make(chan bool)
+	self.idleC = make(chan bool)
 	switchC := self.switchC
 	plog.Debugf("HeadSection: <%s> section process for head %s started", self.id, hex(self.currentBlockHash))
-	self.lock.RUnlock()
+	self.lock.Unlock()
 
 	self.blockHashesRequestTimer = nil
 
diff --git a/blockpool/peers_test.go b/blockpool/peers_test.go
index e32bb6fc8..e5788e379 100644
--- a/blockpool/peers_test.go
+++ b/blockpool/peers_test.go
@@ -145,7 +145,6 @@ func TestAddPeer(t *testing.T) {
 }
 
 func TestPeerPromotionByTdOnBlock(t *testing.T) {
-	t.Skip()
 	test.LogInit()
 	_, blockPool, blockPoolTester := newTestBlockPool(t)
 	blockPoolTester.blockChain[0] = nil
@@ -155,28 +154,26 @@ func TestPeerPromotionByTdOnBlock(t *testing.T) {
 	peer2 := blockPoolTester.newPeer("peer2", 4, 4)
 
 	blockPool.Start()
-	blockPoolTester.tds = make(map[int]int)
-	blockPoolTester.tds[3] = 3
 
-	// pool
 	peer0.AddPeer()
 	peer0.serveBlocks(1, 2)
 	best := peer1.AddPeer()
 	// this tests that peer1 is not promoted over peer0 yet
 	if best {
 		t.Errorf("peer1 (TD=1) should not be set as best")
+		return
 	}
 	best = peer2.AddPeer()
 	peer2.serveBlocks(3, 4)
 	peer2.serveBlockHashes(4, 3, 2, 1)
-	// hashes := blockPoolTester.hashPool.IndexesToHashes([]int{2, 3})
-	peer1.serveBlocks(2, 3)
+	peer1.sendBlocks(3, 4)
 
 	blockPool.RemovePeer("peer2")
 	if blockPool.peers.best.id != "peer1" {
 		t.Errorf("peer1 (TD=3) should be set as best")
+		return
 	}
-	peer1.serveBlocks(0, 1, 2)
+	peer1.serveBlocks(0, 1, 2, 3)
 
 	blockPool.Wait(waitTimeout)
 	blockPool.Stop()