btcd: support feefilter requests.

This only adds support for handling remote peer requests.

btcjson/chainsvrresults.go

@@ -179,6 +179,7 @@ type GetPeerInfoResult struct {
 	StartingHeight int32   `json:"startingheight"`
 	CurrentHeight  int32   `json:"currentheight,omitempty"`
 	BanScore       int32   `json:"banscore"`
+	FeeFilter      int64   `json:"feefilter"`
 	SyncNode       bool    `json:"syncnode"`
 }
 

mempool/mempool.go

@@ -514,6 +514,7 @@ func (mp *TxPool) addTransaction(utxoView *blockchain.UtxoViewpoint, tx *btcutil
 			Added:    time.Now(),
 			Height:   height,
 			Fee:      fee,
+			FeePerKB: fee * 1000 / int64(tx.MsgTx().SerializeSize()),
 		},
 		StartingPriority: mining.CalcPriority(tx.MsgTx(), utxoView, height),
 	}

mining/mining.go

@@ -55,6 +55,9 @@ type TxDesc struct {
 
 	// Fee is the total fee the transaction associated with the entry pays.
 	Fee int64
+
+	// FeePerKB is the fee the transaction pays in Satoshi per 1000 bytes.
+	FeePerKB int64
 }
 
 // TxSource represents a source of transactions to consider for inclusion in
@@ -575,8 +578,7 @@ mempoolLoop:
 			nextBlockHeight)
 
 		// Calculate the fee in Satoshi/kB.
-		txSize := tx.MsgTx().SerializeSize()
-		prioItem.feePerKB = (txDesc.Fee * 1000) / int64(txSize)
+		prioItem.feePerKB = txDesc.FeePerKB
 		prioItem.fee = txDesc.Fee
 
 		// Add the transaction to the priority queue to mark it ready

rpcserver.go

@@ -2229,6 +2229,7 @@ func handleGetPeerInfo(s *rpcServer, cmd interface{}, closeChan <-chan struct{})
 			StartingHeight: statsSnap.StartingHeight,
 			CurrentHeight:  statsSnap.LastBlock,
 			BanScore:       int32(p.banScore.Int()),
+			FeeFilter:      atomic.LoadInt64(&p.feeFilter),
 			SyncNode:       p == syncPeer,
 		}
 		if p.LastPingNonce() != 0 {

rpcserverhelp.go

@@ -391,6 +391,7 @@ var helpDescsEnUS = map[string]string{
 	"getpeerinforesult-startingheight": "The latest block height the peer knew about when the connection was established",
 	"getpeerinforesult-currentheight":  "The current height of the peer",
 	"getpeerinforesult-banscore":       "The ban score",
+	"getpeerinforesult-feefilter":      "The requested minimum fee a transaction must have to be announced to the peer",
 	"getpeerinforesult-syncnode":       "Whether or not the peer is the sync peer",
 
 	// GetPeerInfoCmd help.

server.go

@@ -181,6 +181,9 @@ type server struct {
 // serverPeer extends the peer to maintain state shared by the server and
 // the blockmanager.
 type serverPeer struct {
+	// The following variables must only be used atomically
+	feeFilter int64
+
 	*peer.Peer
 
 	connReq         *connmgr.ConnReq
@@ -782,6 +785,18 @@ func (sp *serverPeer) enforceNodeBloomFlag(cmd string) bool {
 	return true
 }
 
+func (sp *serverPeer) OnFeeFilter(p *peer.Peer, msg *wire.MsgFeeFilter) {
+	// Check that the passed minimum fee is a valid amount.
+	if msg.MinFee < 0 || msg.MinFee > btcutil.MaxSatoshi {
+		peerLog.Debugf("Peer %v sent an invalid feefilter '%v' -- "+
+			"disconnecting", sp, btcutil.Amount(msg.MinFee))
+		sp.Disconnect()
+		return
+	}
+
+	atomic.StoreInt64(&sp.feeFilter, msg.MinFee)
+}
+
 // OnFilterAdd is invoked when a peer receives a filteradd bitcoin
 // message and is used by remote peers to add data to an already loaded bloom
 // filter.  The peer will be disconnected if a filter is not loaded when this
@@ -1316,9 +1331,7 @@ func (s *server) handleRelayInvMsg(state *peerState, msg relayMsg) {
 			if sp.relayTxDisabled() {
 				return
 			}
-			// Don't relay the transaction if there is a bloom
-			// filter loaded and the transaction doesn't match it.
-			if sp.filter.IsLoaded() {
+
 			txD, ok := msg.data.(*mempool.TxDesc)
 			if !ok {
 				peerLog.Warnf("Underlying data for tx" +
@@ -1326,6 +1339,16 @@ func (s *server) handleRelayInvMsg(state *peerState, msg relayMsg) {
 				return
 			}
 
+			// Don't relay the transaction if the transaction fee-per-kb
+			// is less than the peer's feefilter.
+			feeFilter := atomic.LoadInt64(&sp.feeFilter)
+			if feeFilter > 0 && txD.FeePerKB < feeFilter {
+				return
+			}
+
+			// Don't relay the transaction if there is a bloom
+			// filter loaded and the transaction doesn't match it.
+			if sp.filter.IsLoaded() {
 				if !sp.filter.MatchTxAndUpdate(txD.Tx) {
 					return
 				}
@@ -1528,6 +1551,7 @@ func newPeerConfig(sp *serverPeer) *peer.Config {
 			OnGetData:     sp.OnGetData,
 			OnGetBlocks:   sp.OnGetBlocks,
 			OnGetHeaders:  sp.OnGetHeaders,
+			OnFeeFilter:   sp.OnFeeFilter,
 			OnFilterAdd:   sp.OnFilterAdd,
 			OnFilterClear: sp.OnFilterClear,
 			OnFilterLoad:  sp.OnFilterLoad,
@@ -1550,7 +1574,7 @@ func newPeerConfig(sp *serverPeer) *peer.Config {
 		ChainParams:      sp.server.chainParams,
 		Services:         sp.server.services,
 		DisableRelayTx:   cfg.BlocksOnly,
-		ProtocolVersion:  wire.SendHeadersVersion,
+		ProtocolVersion:  wire.FeeFilterVersion,
 	}
 }