Provide the new sequence number in responses. New message Local Discovery to be sent instead of Announcement via IPv4 Broadcast and IPv6 Multicast.

Detecting IPv6 link-local addresses as local ones. Fixes.

Commands.go

@@ -8,7 +8,9 @@ package core
 
 import (
 	"bytes"
+	"encoding/hex"
 	"fmt"
+	"log"
 	"time"
 
 	"github.com/PeernetOfficial/core/dht"
@@ -102,7 +104,7 @@ func (peer *PeerInfo) cmdAnouncement(msg *MessageAnnouncement) {
 		peer.announcementStore(msg.InfoStoreFiles)
 	}
 
-	peer.sendResponse(added, hash2Peers, filesEmbed, hashesNotFound)
+	peer.sendResponse(msg.Sequence, added, hash2Peers, filesEmbed, hashesNotFound)
 }
 
 func (peer *PeerInfo) peer2Record(allowLocal, allowIPv4, allowIPv6 bool) (result *PeerRecord) {
@@ -140,7 +142,7 @@ func (peer *PeerInfo) cmdResponse(msg *MessageResponse) {
 		info := nodesDHT.IRLookup(peer.NodeID, hash2Peer.ID.Hash)
 		if info == nil {
 			// Response to FIND_SELF?
-			if bytes.Equal(info.Key, nodeID) && len(hash2Peer.Closest) > 0 {
+			if bytes.Equal(hash2Peer.ID.Hash, nodeID) && len(hash2Peer.Closest) > 0 {
 				peer.cmdResponseFindSelf(msg, hash2Peer.Closest)
 			}
 			continue
@@ -196,6 +198,30 @@ func (peer *PeerInfo) cmdChat(msg *MessageRaw) {
 	fmt.Printf("Chat from '%s': %s\n", msg.connection.Address.String(), string(msg.PacketRaw.Payload))
 }
 
+// cmdLocalDiscovery handles an incoming announcement via local discovery
+func (peer *PeerInfo) cmdLocalDiscovery(msg *MessageAnnouncement) {
+	// only accept local discovery message from private IPs for IPv4
+	// IPv6 DHCP routers typically assign public IPv6s and they can join multicast in the local network.
+	if msg.connection.IsIPv4() && !msg.connection.IsLocal() {
+		log.Printf("cmdLocalDiscovery message received from non-local IP %s peer ID %s\n", msg.connection.Address.String(), hex.EncodeToString(msg.SenderPublicKey.SerializeCompressed()))
+		return
+	}
+
+	var added bool
+	if peer == nil {
+		// The added check is required due to potential race condition; initially the client may receive multiple incoming announcement from the same peer via different connections.
+		if peer, added = PeerlistAdd(msg.SenderPublicKey, msg.connection); !added {
+			return
+		}
+
+		fmt.Printf("Incoming initial local discovery from %s\n", msg.connection.Address.String())
+		//} else {
+		//	fmt.Printf("Incoming secondary local discovery from %s\n", msg.connection.Address.String())
+	}
+
+	peer.sendAnnouncement(true, true, nil, nil, nil)
+}
+
 // pingTime is the time in seconds to send out ping messages
 const pingTime = 10
 

Message Encoding.go

@@ -28,13 +28,14 @@ var UserAgent = "Peernet Core/0.1"
 // Commands between peers
 const (
 	// Peer List Management
-	CommandAnnouncement = 0 // Announcement
-	CommandResponse     = 1 // Response
-	CommandPing         = 2 // Keep-alive message (no payload).
-	CommandPong         = 3 // Response to ping (no payload).
+	CommandAnnouncement   = 0 // Announcement
+	CommandResponse       = 1 // Response
+	CommandPing           = 2 // Keep-alive message (no payload).
+	CommandPong           = 3 // Response to ping (no payload).
+	CommandLocalDiscovery = 4 // Local discovery
 
 	// Blockchain
-	CommandGet = 4 // Request blocks for specified peer.
+	CommandGet = 6 // Request blocks for specified peer.
 
 	// File Discovery
 
@@ -762,11 +763,11 @@ func (peer *PeerInfo) sendAnnouncement(sendUA, findSelf bool, findPeer []KeyHash
 }
 
 // sendResponse sends the response message
-func (peer *PeerInfo) sendResponse(sendUA bool, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte) (err error) {
+func (peer *PeerInfo) sendResponse(sequence uint32, sendUA bool, hash2Peers []Hash2Peer, filesEmbed []EmbeddedFileData, hashesNotFound [][]byte) (err error) {
 	packets, err := msgEncodeResponse(sendUA, hash2Peers, filesEmbed, hashesNotFound)
 
 	for _, packet := range packets {
-		peer.send(&PacketRaw{Command: CommandResponse, Payload: packet})
+		peer.send(&PacketRaw{Command: CommandResponse, Payload: packet, Sequence: sequence})
 	}
 
 	return err

Network Detection.go

@@ -249,13 +249,16 @@ func networkChangeIPRemove(iface net.Interface, address net.Addr) {
 	}
 }
 
-// IsIPLocal reports whether ip is a private (local) address. [forked function]
+// IsIPLocal reports whether ip is a private (local) address.
 // The identification of private, or local, unicast addresses uses address type
-// indentification as defined in RFC 1918 for ip4 and RFC 4193 for ip6 with the exception of ip4 directed broadcast addresses.
+// indentification as defined in RFC 1918 for ip4 and RFC 4193 (fc00::/7) for ip6 with the exception of ip4 directed broadcast addresses.
 // Unassigned, reserved, multicast and limited-broadcast addresses are not handled and will return false.
+// IPv6 link-local addresses (fe80::/10) are included in this check.
 func IsIPLocal(ip net.IP) bool {
 	if ip4 := ip.To4(); ip4 != nil {
 		return ip4[0] == 10 || (ip4[0] == 172 && ip4[1]&0xf0 == 16) || (ip4[0] == 192 && ip4[1] == 168)
 	}
-	return len(ip) == net.IPv6len && ip[0]&0xfe == 0xfc
+	return len(ip) == net.IPv6len &&
+		(ip[0]&0xfe == 0xfc || // fc00::/7
+			(ip[0] == 0xfe && ip[1]&0xC0 == 0x80)) // fe80::/10
 }

Network IPv4 Broadcast.go

@@ -95,7 +95,7 @@ func (network *Network) BroadcastIPv4Send() (err error) {
 		return err
 	}
 
-	raw, err := PacketEncrypt(peerPrivateKey, ipv4BroadcastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandAnnouncement, Payload: packets[0]})
+	raw, err := PacketEncrypt(peerPrivateKey, ipv4BroadcastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandLocalDiscovery, Payload: packets[0]})
 	if err != nil {
 		return err
 	}

Network IPv6 Multicast.go

@@ -141,7 +141,7 @@ func (network *Network) MulticastIPv6Send() (err error) {
 		return err
 	}
 
-	raw, err := PacketEncrypt(peerPrivateKey, ipv6MulticastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandAnnouncement, Payload: packets[0]})
+	raw, err := PacketEncrypt(peerPrivateKey, ipv6MulticastPublicKey, &PacketRaw{Protocol: ProtocolVersion, Command: CommandLocalDiscovery, Payload: packets[0]})
 	if err != nil {
 		return err
 	}

Network.go

@@ -166,6 +166,11 @@ func packetWorker(packets <-chan networkWire) {
 				peer.cmdResponse(response)
 			}
 
+		case CommandLocalDiscovery: // Local discovery, sent via IPv4 broadcast and IPv6 multicast
+			if announce, _ := msgDecodeAnnouncement(raw); announce != nil {
+				peer.cmdLocalDiscovery(announce)
+			}
+
 		case CommandPing: // Ping
 			peer.cmdPing(raw)
 

Peer ID.go

@@ -49,7 +49,7 @@ func initPeerID() {
 	nodeID = publicKey2NodeID(peerPublicKey)
 
 	// save the newly generated private key into the config
-	config.PrivateKey = hex.EncodeToString(peerPublicKey.SerializeCompressed())
+	config.PrivateKey = hex.EncodeToString(peerPrivateKey.Serialize())
 
 	saveConfig()
 }