253 lines
7.0 KiB
Go
253 lines
7.0 KiB
Go
package router
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import (
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"fmt"
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"log"
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"net"
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"time"
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)
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type LocalPeer struct {
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*Peer
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router *Router
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actionChan chan<- LocalPeerAction
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}
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type LocalPeerAction func()
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func NewLocalPeer(name PeerName, nickName string, router *Router) *LocalPeer {
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return &LocalPeer{Peer: NewPeer(name, nickName, 0, 0), router: router}
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}
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func (peer *LocalPeer) Start() {
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actionChan := make(chan LocalPeerAction, ChannelSize)
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peer.actionChan = actionChan
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go peer.actorLoop(actionChan)
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}
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func (peer *LocalPeer) Forward(dstPeer *Peer, df bool, frame []byte, dec *EthernetDecoder) error {
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return peer.Relay(peer.Peer, dstPeer, df, frame, dec)
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}
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func (peer *LocalPeer) Broadcast(df bool, frame []byte, dec *EthernetDecoder) {
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peer.RelayBroadcast(peer.Peer, df, frame, dec)
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}
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func (peer *LocalPeer) Relay(srcPeer, dstPeer *Peer, df bool, frame []byte, dec *EthernetDecoder) error {
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relayPeerName, found := peer.router.Routes.Unicast(dstPeer.Name)
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if !found {
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// Not necessarily an error as there could be a race with the
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// dst disappearing whilst the frame is in flight
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log.Println("Received packet for unknown destination:", dstPeer.FullName())
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return nil
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}
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conn, found := peer.ConnectionTo(relayPeerName)
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if !found {
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// Again, could just be a race, not necessarily an error
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log.Println("Unable to find connection to relay peer", relayPeerName)
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return nil
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}
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return conn.(*LocalConnection).Forward(df, &ForwardedFrame{
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srcPeer: srcPeer,
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dstPeer: dstPeer,
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frame: frame},
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dec)
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}
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func (peer *LocalPeer) RelayBroadcast(srcPeer *Peer, df bool, frame []byte, dec *EthernetDecoder) {
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nextHops := peer.router.Routes.Broadcast(srcPeer.Name)
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if len(nextHops) == 0 {
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return
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}
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for _, conn := range peer.ConnectionsTo(nextHops) {
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err := conn.(*LocalConnection).Forward(df, &ForwardedFrame{
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srcPeer: srcPeer,
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dstPeer: conn.Remote(),
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frame: frame},
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dec)
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if err != nil {
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if ftbe, ok := err.(FrameTooBigError); ok {
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log.Printf("dropping too big DF broadcast frame (%v -> %v): PMTU= %v\n", dec.ip.DstIP, dec.ip.SrcIP, ftbe.EPMTU)
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} else {
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log.Println(err)
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}
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}
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}
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}
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func (peer *LocalPeer) ConnectionsTo(names []PeerName) []Connection {
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conns := make([]Connection, 0, len(names))
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peer.RLock()
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defer peer.RUnlock()
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for _, name := range names {
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conn, found := peer.connections[name]
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// Again, !found could just be due to a race.
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if found {
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conns = append(conns, conn)
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}
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}
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return conns
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}
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func (peer *LocalPeer) CreateConnection(peerAddr string, acceptNewPeer bool) error {
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if err := peer.checkConnectionLimit(); err != nil {
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return err
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}
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// We're dialing the remote so that means connections will come from random ports
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addrStr := peer.router.NormalisePeerAddr(peerAddr)
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tcpAddr, tcpErr := net.ResolveTCPAddr("tcp4", addrStr)
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udpAddr, udpErr := net.ResolveUDPAddr("udp4", addrStr)
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if tcpErr != nil || udpErr != nil {
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// they really should have the same value, but just in case...
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if tcpErr == nil {
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return udpErr
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}
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return tcpErr
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}
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tcpConn, err := net.DialTCP("tcp4", nil, tcpAddr)
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if err != nil {
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return err
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}
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connRemote := NewRemoteConnection(peer.Peer, nil, tcpConn.RemoteAddr().String(), true, false)
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connLocal := NewLocalConnection(connRemote, tcpConn, udpAddr, peer.router)
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connLocal.Start(acceptNewPeer)
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return nil
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}
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// ACTOR client API
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const (
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PAddConnection = iota
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PConnectionEstablished
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PDeleteConnection
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)
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// Sync.
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func (peer *LocalPeer) AddConnection(conn *LocalConnection) {
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resultChan := make(chan interface{})
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peer.actionChan <- func() {
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peer.handleAddConnection(conn)
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resultChan <- nil
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}
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<-resultChan
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}
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// Async.
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func (peer *LocalPeer) ConnectionEstablished(conn *LocalConnection) {
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peer.actionChan <- func() {
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peer.handleConnectionEstablished(conn)
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}
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}
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// Sync.
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func (peer *LocalPeer) DeleteConnection(conn *LocalConnection) {
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resultChan := make(chan interface{})
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peer.actionChan <- func() {
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peer.handleDeleteConnection(conn)
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resultChan <- nil
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}
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<-resultChan
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}
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// ACTOR server
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func (peer *LocalPeer) actorLoop(actionChan <-chan LocalPeerAction) {
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gossipTimer := time.Tick(GossipInterval)
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for {
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select {
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case action := <-actionChan:
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action()
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case <-gossipTimer:
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peer.router.SendAllGossip()
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}
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}
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}
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func (peer *LocalPeer) handleAddConnection(conn Connection) {
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if peer.Peer != conn.Local() {
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log.Fatal("Attempt made to add connection to peer where peer is not the source of connection")
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}
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if conn.Remote() == nil {
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log.Fatal("Attempt made to add connection to peer with unknown remote peer")
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}
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toName := conn.Remote().Name
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dupErr := fmt.Errorf("Multiple connections to %s added to %s", conn.Remote().FullName(), peer.FullName())
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// deliberately non symmetrical
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if dupConn, found := peer.connections[toName]; found {
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if dupConn == conn {
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return
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}
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switch conn.BreakTie(dupConn) {
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case TieBreakWon:
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dupConn.Shutdown(dupErr)
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peer.handleDeleteConnection(dupConn)
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case TieBreakLost:
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conn.Shutdown(dupErr)
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return
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case TieBreakTied:
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// oh good grief. Sod it, just kill both of them.
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conn.Shutdown(dupErr)
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dupConn.Shutdown(dupErr)
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peer.handleDeleteConnection(dupConn)
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return
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}
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}
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if err := peer.checkConnectionLimit(); err != nil {
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conn.Shutdown(err)
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return
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}
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_, isConnectedPeer := peer.router.Routes.Unicast(toName)
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peer.addConnection(conn)
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if isConnectedPeer {
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conn.Log("connection added")
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} else {
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conn.Log("connection added (new peer)")
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peer.router.SendAllGossipDown(conn)
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}
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peer.broadcastPeerUpdate(conn.Remote())
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}
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func (peer *LocalPeer) handleConnectionEstablished(conn Connection) {
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if peer.Peer != conn.Local() {
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log.Fatal("Peer informed of active connection where peer is not the source of connection")
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}
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if dupConn, found := peer.connections[conn.Remote().Name]; !found || conn != dupConn {
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conn.Shutdown(fmt.Errorf("Cannot set unknown connection active"))
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return
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}
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peer.connectionEstablished(conn)
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conn.Log("connection fully established")
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peer.broadcastPeerUpdate()
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}
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func (peer *LocalPeer) handleDeleteConnection(conn Connection) {
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if peer.Peer != conn.Local() {
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log.Fatal("Attempt made to delete connection from peer where peer is not the source of connection")
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}
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if conn.Remote() == nil {
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log.Fatal("Attempt made to delete connection to peer with unknown remote peer")
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}
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toName := conn.Remote().Name
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if connFound, found := peer.connections[toName]; !found || connFound != conn {
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return
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}
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peer.deleteConnection(conn)
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conn.Log("connection deleted")
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// Must do garbage collection first to ensure we don't send out an
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// update with unreachable peers (can cause looping)
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peer.router.Peers.GarbageCollect()
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peer.broadcastPeerUpdate()
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}
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func (peer *LocalPeer) broadcastPeerUpdate(peers ...*Peer) {
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peer.router.Routes.Recalculate()
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peer.router.TopologyGossip.GossipBroadcast(NewTopologyGossipData(peer.router.Peers, append(peers, peer.Peer)...))
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}
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func (peer *LocalPeer) checkConnectionLimit() error {
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if 0 != peer.router.ConnLimit && peer.ConnectionCount() >= peer.router.ConnLimit {
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return fmt.Errorf("Connection limit reached (%v)", peer.router.ConnLimit)
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}
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return nil
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}
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