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209 lines
4.9 KiB
209 lines
4.9 KiB
package peer
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import (
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"errors"
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"sync"
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"sync/atomic"
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. "github.com/tendermint/tendermint/binary"
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. "github.com/tendermint/tendermint/common"
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"github.com/tendermint/tendermint/merkle"
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)
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/*
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A client is half of a p2p system.
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It can reach out to the network and establish connections with other peers.
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A client doesn't listen for incoming connections -- that's done by the server.
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All communication amongst peers are multiplexed by "channels".
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(Not the same as Go "channels")
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To send a message, encapsulate it into a "Packet" and send it to each peer.
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You can find all connected and active peers by iterating over ".Peers()".
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".Broadcast()" is provided for convenience, but by iterating over
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the peers manually the caller can decide which subset receives a message.
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Incoming messages are received by calling ".Receive()".
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*/
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type Client struct {
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addrBook *AddrBook
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targetNumPeers int
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makePeerFn func(*Connection) *Peer
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self *Peer
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pktRecvQueues map[String]chan *InboundPacket
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peersMtx sync.Mutex
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peers merkle.Tree // addr -> *Peer
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quit chan struct{}
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stopped uint32
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}
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var (
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ErrClientStopped = errors.New("Client already stopped")
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ErrClientDuplicatePeer = errors.New("Duplicate peer")
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)
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// "makePeerFn" is a factory method for generating new peers from new *Connections.
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// "makePeerFn(nil)" must return a prototypical peer that represents the self "peer".
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func NewClient(makePeerFn func(*Connection) *Peer) *Client {
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self := makePeerFn(nil)
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if self == nil {
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Panicf("makePeerFn(nil) must return a prototypical peer for self")
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}
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pktRecvQueues := make(map[String]chan *InboundPacket)
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for chName, _ := range self.channels {
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pktRecvQueues[chName] = make(chan *InboundPacket)
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}
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c := &Client{
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addrBook: nil, // TODO
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targetNumPeers: 0, // TODO
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makePeerFn: makePeerFn,
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self: self,
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pktRecvQueues: pktRecvQueues,
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peers: merkle.NewIAVLTree(nil),
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quit: make(chan struct{}),
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stopped: 0,
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}
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// automatically start
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c.start()
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return c
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}
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func (c *Client) start() {
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// Handle PEX messages
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// TODO: hmm
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// go peerExchangeHandler(c)
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}
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func (c *Client) Stop() {
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log.Infof("Stopping client")
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// lock
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c.peersMtx.Lock()
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if atomic.CompareAndSwapUint32(&c.stopped, 0, 1) {
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close(c.quit)
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// stop each peer.
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for peerValue := range c.peers.Values() {
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peer := peerValue.(*Peer)
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peer.stop()
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}
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// empty tree.
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c.peers = merkle.NewIAVLTree(nil)
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}
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c.peersMtx.Unlock()
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// unlock
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}
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func (c *Client) AddPeerWithConnection(conn *Connection, outgoing bool) (*Peer, error) {
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if atomic.LoadUint32(&c.stopped) == 1 {
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return nil, ErrClientStopped
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}
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log.Infof("Adding peer with connection: %v, outgoing: %v", conn, outgoing)
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peer := c.makePeerFn(conn)
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peer.outgoing = outgoing
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err := c.addPeer(peer)
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if err != nil {
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return nil, err
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}
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go peer.start(c.pktRecvQueues, c.StopPeerForError)
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return peer, nil
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}
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func (c *Client) Broadcast(pkt Packet) (numSuccess, numFailure int) {
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if atomic.LoadUint32(&c.stopped) == 1 {
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return
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}
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log.Tracef("Broadcast on [%v] len: %v", pkt.Channel, len(pkt.Bytes))
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for v := range c.peers.Values() {
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peer := v.(*Peer)
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success := peer.TryQueue(pkt)
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log.Tracef("Broadcast for peer %v success: %v", peer, success)
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if success {
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numSuccess += 1
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} else {
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numFailure += 1
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}
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}
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return
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}
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/*
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Receive blocks on a channel until a message is found.
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*/
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func (c *Client) Receive(chName String) *InboundPacket {
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if atomic.LoadUint32(&c.stopped) == 1 {
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return nil
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}
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log.Tracef("Receive on [%v]", chName)
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q := c.pktRecvQueues[chName]
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if q == nil {
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Panicf("Expected pktRecvQueues[%f], found none", chName)
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}
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select {
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case <-c.quit:
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return nil
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case inPacket := <-q:
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return inPacket
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}
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}
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func (c *Client) Peers() merkle.Tree {
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// lock & defer
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c.peersMtx.Lock()
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defer c.peersMtx.Unlock()
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return c.peers.Copy()
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// unlock deferred
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}
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// Disconnect from a peer due to external error.
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// TODO: make record depending on reason.
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func (c *Client) StopPeerForError(peer *Peer, reason interface{}) {
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log.Infof("%v errored: %v", peer, reason)
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c.StopPeer(peer, false)
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}
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// Disconnect from a peer.
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// If graceful is true, last message sent is a disconnect message.
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// TODO: handle graceful disconnects.
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func (c *Client) StopPeer(peer *Peer, graceful bool) {
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// lock
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c.peersMtx.Lock()
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peerValue, _ := c.peers.Remove(peer.RemoteAddress())
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c.peersMtx.Unlock()
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// unlock
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peer_ := peerValue.(*Peer)
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if peer_ != nil {
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peer_.stop()
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}
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}
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func (c *Client) addPeer(peer *Peer) error {
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addr := peer.RemoteAddress()
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// lock & defer
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c.peersMtx.Lock()
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defer c.peersMtx.Unlock()
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if c.stopped == 1 {
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return ErrClientStopped
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}
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if !c.peers.Has(addr) {
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log.Tracef("Actually putting addr: %v, peer: %v", addr, peer)
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c.peers.Put(addr, peer)
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return nil
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} else {
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// ignore duplicate peer for addr.
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log.Infof("Ignoring duplicate peer for addr %v", addr)
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return ErrClientDuplicatePeer
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}
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// unlock deferred
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}
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