Switch over to new btcwire Read/WriteMessageN.

This commit adds byte counters to each peer using the new btcwire
ReadMessageN and WriteMessageN functions to obtain the number of bytes
read and written, respectively.  It also returns those byte counters via
the PeerInfo struct which is used to populate the RPC getpeerinfo reply.

Closes #83.

peer.go

@@ -137,6 +137,8 @@ type peer struct {
 	timeConnected      time.Time
 	lastSend           time.Time
 	lastRecv           time.Time
+	bytesRead          uint64
+	bytesWritten       uint64
 	inbound            bool
 	connected          int32
 	disconnect         int32 // only to be used atomically
@@ -951,11 +953,13 @@ func (p *peer) handlePongMsg(msg *btcwire.MsgPong) {
 }
 
 // readMessage reads the next bitcoin message from the peer with logging.
-func (p *peer) readMessage() (msg btcwire.Message, buf []byte, err error) {
+func (p *peer) readMessage() (btcwire.Message, []byte, error) {
-	msg, buf, err = btcwire.ReadMessage(p.conn, p.protocolVersion, p.btcnet)
+	n, msg, buf, err := btcwire.ReadMessageN(p.conn, p.protocolVersion, p.btcnet)
 	if err != nil {
-		return
+		p.bytesRead += uint64(n)
+		return nil, nil, err
 	}
+	p.bytesRead += uint64(n)
 
 	// Use closures to log expensive operations so they are only run when
 	// the logging level requires it.
@@ -975,7 +979,7 @@ func (p *peer) readMessage() (msg btcwire.Message, buf []byte, err error) {
 		return spew.Sdump(buf)
 	}))
 
-	return
+	return msg, buf, nil
 }
 
 // writeMessage sends a bitcoin Message to the peer with logging.
@@ -1019,12 +1023,14 @@ func (p *peer) writeMessage(msg btcwire.Message) {
 	}))
 
 	// Write the message to the peer.
-	err := btcwire.WriteMessage(p.conn, msg, p.protocolVersion, p.btcnet)
+	n, err := btcwire.WriteMessageN(p.conn, msg, p.protocolVersion, p.btcnet)
 	if err != nil {
+		p.bytesWritten += uint64(n)
 		p.Disconnect()
 		p.logError("Can't send message: %v", err)
 		return
 	}
+	p.bytesWritten += uint64(n)
 }
 
 // isAllowedByRegression returns whether or not the passed error is allowed by

server.go

@@ -264,8 +264,8 @@ type PeerInfo struct {
 	Services       string `json:"services"`
 	LastSend       int64  `json:"lastsend"`
 	LastRecv       int64  `json:"lastrecv"`
-	BytesSent      int    `json:"bytessent"`
+	BytesSent      uint64 `json:"bytessent"`
-	BytesRecv      int    `json:"bytesrecv"`
+	BytesRecv      uint64 `json:"bytesrecv"`
 	PingTime       int64  `json:"pingtime"`
 	PingWait       int64  `json:"pingwait,omitempty"`
 	ConnTime       int64  `json:"conntime"`
@@ -328,8 +328,8 @@ func (s *server) handleQuery(querymsg interface{}, state *peerState) {
 				Services:       fmt.Sprintf("%08d", p.services),
 				LastSend:       p.lastSend.Unix(),
 				LastRecv:       p.lastRecv.Unix(),
-				BytesSent:      0, // TODO(oga) we need this from wire.
+				BytesSent:      p.bytesWritten,
-				BytesRecv:      0, // TODO(oga) we need this from wire.
+				BytesRecv:      p.bytesRead,
 				ConnTime:       p.timeConnected.Unix(),
 				Version:        p.protocolVersion,
 				SubVer:         p.userAgent,