Add initial relay code

relay/server/peer.go

@@ -0,0 +1,113 @@
+package server
+
+import (
+	"fmt"
+	"net"
+	"sync"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type Participant struct {
+	ChannelID        uint16
+	ChannelIDForeign uint16
+	ConnForeign      net.Conn
+	Peer             *Peer
+}
+
+type Peer struct {
+	Log  *log.Entry
+	id   string
+	conn net.Conn
+
+	pendingParticipantByChannelID map[uint16]*Participant
+	participantByID               map[uint16]*Participant // used for package transfer
+	participantByPeerID           map[string]*Participant // used for channel linking
+
+	lastId     uint16
+	lastIdLock sync.Mutex
+}
+
+func NewPeer(id string, conn net.Conn) *Peer {
+	return &Peer{
+		Log:                           log.WithField("peer_id", id),
+		id:                            id,
+		conn:                          conn,
+		pendingParticipantByChannelID: make(map[uint16]*Participant),
+		participantByID:               make(map[uint16]*Participant),
+		participantByPeerID:           make(map[string]*Participant),
+	}
+}
+func (p *Peer) BindChannel(remotePeerId string) uint16 {
+	ch, ok := p.participantByPeerID[remotePeerId]
+	if ok {
+		return ch.ChannelID
+	}
+
+	channelID := p.newChannelID()
+	channel := &Participant{
+		ChannelID: channelID,
+	}
+	p.pendingParticipantByChannelID[channelID] = channel
+	p.participantByPeerID[remotePeerId] = channel
+	return channelID
+}
+
+func (p *Peer) UnBindChannel(remotePeerId string) {
+	pa, ok := p.participantByPeerID[remotePeerId]
+	if !ok {
+		return
+	}
+
+	p.Log.Debugf("unbind channel with '%s': %d", remotePeerId, pa.ChannelID)
+	p.pendingParticipantByChannelID[pa.ChannelID] = pa
+	delete(p.participantByID, pa.ChannelID)
+}
+
+func (p *Peer) AddParticipant(peer *Peer, remoteChannelID uint16) (uint16, bool) {
+	participant, ok := p.participantByPeerID[peer.ID()]
+	if !ok {
+		return 0, false
+	}
+	participant.ChannelIDForeign = remoteChannelID
+	participant.ConnForeign = peer.conn
+	participant.Peer = peer
+
+	delete(p.pendingParticipantByChannelID, participant.ChannelID)
+	p.participantByID[participant.ChannelID] = participant
+	return participant.ChannelID, true
+}
+
+func (p *Peer) DeleteParticipants() {
+	for _, participant := range p.participantByID {
+		participant.Peer.UnBindChannel(p.id)
+	}
+}
+
+func (p *Peer) ConnByChannelID(dstID uint16) (uint16, net.Conn, error) {
+	ch, ok := p.participantByID[dstID]
+	if !ok {
+		return 0, nil, fmt.Errorf("destination channel not found")
+	}
+
+	return ch.ChannelIDForeign, ch.ConnForeign, nil
+}
+
+func (p *Peer) ID() string {
+	return p.id
+}
+
+func (p *Peer) newChannelID() uint16 {
+	p.lastIdLock.Lock()
+	defer p.lastIdLock.Unlock()
+	for {
+		p.lastId++
+		if _, ok := p.pendingParticipantByChannelID[p.lastId]; ok {
+			continue
+		}
+		if _, ok := p.participantByID[p.lastId]; ok {
+			continue
+		}
+		return p.lastId
+	}
+}