From 1821ff1a0ef8c697b0f303dff755949ec6ee5cf0 Mon Sep 17 00:00:00 2001
From: anthdm <anthony@academiclabs.co>
Date: Sun, 28 Jan 2018 14:59:32 +0100
Subject: [PATCH] handle address list message.

---
 pkg/network/payload/addr.go | 16 +++++++++++++++-
 pkg/network/peer.go         |  3 ++-
 pkg/network/server.go       | 26 +++++++++++++++++++++++---
 pkg/network/tcp.go          | 26 ++++++++++++++------------
 4 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/pkg/network/payload/addr.go b/pkg/network/payload/addr.go
index 08ecd61fa..9711a0ece 100644
--- a/pkg/network/payload/addr.go
+++ b/pkg/network/payload/addr.go
@@ -3,16 +3,30 @@ package payload
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 )
 
-// Endpoint host + port of a node.
+// Endpoint host + port of a node, compatible with net.Addr.
 type Endpoint struct {
 	IP   [16]byte // TODO: make a uint128 type
 	Port uint16
 }
 
+// Network implements the net.Addr interface.
+func (e Endpoint) Network() string { return "tcp" }
+
+// String implements the net.Addr interface.
+func (e Endpoint) String() string {
+	b := make([]uint8, 4)
+	for i := 0; i < 4; i++ {
+		b[i] = byte(e.IP[len(e.IP)-4+i])
+	}
+	return fmt.Sprintf("%d.%d.%d.%d:%d", b[0], b[1], b[2], b[3], e.Port)
+}
+
 // AddrWithTime payload
 type AddrWithTime struct {
+	// Timestamp the node connected to the network.
 	Timestamp uint32
 	Services  uint64
 	Addr      Endpoint
diff --git a/pkg/network/peer.go b/pkg/network/peer.go
index 68adb4b00..d0c54dcb1 100644
--- a/pkg/network/peer.go
+++ b/pkg/network/peer.go
@@ -7,7 +7,8 @@ import (
 
 // Peer represents a remote node, backed by TCP transport.
 type Peer struct {
-	// underlaying TCP connection
+	id uint32
+	// underlying TCP connection
 	conn net.Conn
 	// channel to coordinate message writes back to the connection.
 	send chan *Message
diff --git a/pkg/network/server.go b/pkg/network/server.go
index c9e3adaae..9f5d615c7 100644
--- a/pkg/network/server.go
+++ b/pkg/network/server.go
@@ -7,6 +7,7 @@ import (
 	"net"
 	"os"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/anthdm/neo-go/pkg/network/payload"
@@ -23,7 +24,7 @@ const (
 
 var (
 	// rpcLogger used for debugging RPC messages between nodes.
-	rpcLogger = log.New(os.Stdout, "RPC :: ", 0)
+	rpcLogger = log.New(os.Stdout, "", 0)
 )
 
 type messageTuple struct {
@@ -35,6 +36,8 @@ type messageTuple struct {
 type Server struct {
 	logger *log.Logger
 
+	mtx sync.RWMutex
+
 	// id of the server
 	id uint32
 
@@ -171,7 +174,7 @@ func (s *Server) loop() {
 // TODO: unregister peers on error.
 // processMessage processes the received message from a remote node.
 func (s *Server) processMessage(msg *Message, peer *Peer) error {
-	rpcLogger.Printf("IN :: %s :: %+v", msg.commandType(), msg.Payload)
+	rpcLogger.Printf("[NODE %d] :: IN :: %s :: %+v", peer.id, msg.commandType(), msg.Payload)
 
 	switch msg.commandType() {
 	case cmdVersion:
@@ -216,6 +219,7 @@ func (s *Server) handleVersionCmd(v *payload.Version, peer *Peer) error {
 	// we respond with a verack, we successfully received peer's version
 	// at this point.
 	peer.verack = true
+	peer.id = v.Nonce
 	verackMsg := newMessage(s.net, cmdVerack, nil)
 	peer.send <- verackMsg
 
@@ -224,13 +228,29 @@ func (s *Server) handleVersionCmd(v *payload.Version, peer *Peer) error {
 	return nil
 }
 
+// When the remote node reveals its known peers we try to connect to all of them.
 func (s *Server) handleAddrCmd(addrList *payload.AddressList, peer *Peer) error {
 	for _, addr := range addrList.Addrs {
-		fmt.Println(addr)
+		if !s.addrAlreadyConnected(addr.Addr) {
+			go connectToRemoteNode(s, addr.Addr.String())
+		}
 	}
 	return nil
 }
 
+func (s *Server) addrAlreadyConnected(addr net.Addr) bool {
+	// TODO: check for race conditions
+	//s.mtx.RLock()
+	//defer s.mtx.RUnlock()
+
+	for peer := range s.peers {
+		if peer.conn.RemoteAddr().String() == addr.String() {
+			return true
+		}
+	}
+	return false
+}
+
 // After receiving the "getaddr" the server needs to respond with an "addr" message.
 // providing information about the other nodes in the network.
 // e.g. this server's connected peers.
diff --git a/pkg/network/tcp.go b/pkg/network/tcp.go
index 408be9b06..06249d132 100644
--- a/pkg/network/tcp.go
+++ b/pkg/network/tcp.go
@@ -2,7 +2,6 @@ package network
 
 import (
 	"io"
-	"log"
 	"net"
 )
 
@@ -21,19 +20,22 @@ func listenTCP(s *Server, port string) error {
 	}
 }
 
+func connectToRemoteNode(s *Server, address string) {
+	conn, err := net.Dial("tcp", address)
+	if err != nil {
+		s.logger.Printf("failed to connects to remote node %s", address)
+		if conn != nil {
+			conn.Close()
+		}
+		return
+	}
+	s.logger.Printf("connected to %s", conn.RemoteAddr())
+	go handleConnection(s, conn, false)
+}
+
 func connectToSeeds(s *Server, addrs []string) {
 	for _, addr := range addrs {
-		go func(addr string) {
-			conn, err := net.Dial("tcp", addr)
-			if err != nil {
-				log.Printf("failed to connect to remote node %s: %s", addr, err)
-				if conn != nil {
-					conn.Close()
-				}
-				return
-			}
-			go handleConnection(s, conn, false)
-		}(addr)
+		go connectToRemoteNode(s, addr)
 	}
 }