p2p, dex: rework connection management (#183)

* p2p, dex: rework connection management
* dex: refresh our node record periodically
* dex: don't send new record event if no new record

1 files changed, 26 insertions, 120 deletions

diff --git a/p2p/server.go b/p2p/server.go
index 36b1721a5..58b76a708 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -182,8 +182,6 @@ type Server struct {
 	removedirect  chan *enode.Node
 	addtrusted    chan *enode.Node
 	removetrusted chan *enode.Node
-	addgroup      chan *dialGroup
-	removegroup   chan *dialGroup
 	posthandshake chan *conn
 	addpeer       chan *conn
 	delpeer       chan peerDrop
@@ -206,7 +204,6 @@ const (
 	dynDialedConn connFlag = 1 << iota
 	staticDialedConn
 	directDialedConn
-	groupDialedConn
 	inboundConn
 	trustedConn
 )
@@ -260,9 +257,6 @@ func (f connFlag) String() string {
 	if f&directDialedConn != 0 {
 		s += "-directdial"
 	}
-	if f&groupDialedConn != 0 {
-		s += "-groupdial"
-	}
 	if f&inboundConn != 0 {
 		s += "-inbound"
 	}
@@ -357,26 +351,6 @@ func (srv *Server) RemoveDirectPeer(node *enode.Node) {
 	}
 }
 
-func (srv *Server) AddGroup(name string, nodes []*enode.Node, num uint64) {
-	m := map[enode.ID]*enode.Node{}
-	for _, node := range nodes {
-		m[node.ID()] = node
-	}
-	g := &dialGroup{name: name, nodes: m, num: num}
-	select {
-	case srv.addgroup <- g:
-	case <-srv.quit:
-	}
-}
-
-func (srv *Server) RemoveGroup(name string) {
-	g := &dialGroup{name: name}
-	select {
-	case srv.removegroup <- g:
-	case <-srv.quit:
-	}
-}
-
 // AddTrustedPeer adds the given node to a reserved whitelist which allows the
 // node to always connect, even if the slot are full.
 func (srv *Server) AddTrustedPeer(node *enode.Node) {
@@ -524,8 +498,6 @@ func (srv *Server) Start() (err error) {
 	srv.removestatic = make(chan *enode.Node)
 	srv.adddirect = make(chan *enode.Node)
 	srv.removedirect = make(chan *enode.Node)
-	srv.addgroup = make(chan *dialGroup)
-	srv.removegroup = make(chan *dialGroup)
 	srv.addtrusted = make(chan *enode.Node)
 	srv.removetrusted = make(chan *enode.Node)
 	srv.peerOp = make(chan peerOpFunc)
@@ -689,8 +661,6 @@ type dialer interface {
 	removeStatic(*enode.Node)
 	addDirect(*enode.Node)
 	removeDirect(*enode.Node)
-	addGroup(*dialGroup)
-	removeGroup(*dialGroup)
 }
 
 func (srv *Server) run(dialstate dialer) {
@@ -699,15 +669,12 @@ func (srv *Server) run(dialstate dialer) {
 	defer srv.nodedb.Close()
 
 	var (
-		peers         = make(map[enode.ID]*Peer)
-		inboundCount  = 0
-		trusted       = make(map[enode.ID]bool, len(srv.TrustedNodes))
-		peerflags     = make(map[enode.ID]connFlag)
-		groupRefCount = make(map[enode.ID]int32)
-		groups        = make(map[string]*dialGroup)
-		taskdone      = make(chan task, maxActiveDialTasks)
-		runningTasks  []task
-		queuedTasks   []task // tasks that can't run yet
+		peers        = make(map[enode.ID]*Peer)
+		inboundCount = 0
+		trusted      = make(map[enode.ID]bool, len(srv.TrustedNodes))
+		taskdone     = make(chan task, maxActiveDialTasks)
+		runningTasks []task
+		queuedTasks  []task // tasks that can't run yet
 	)
 	// Put trusted nodes into a map to speed up checks.
 	// Trusted peers are loaded on startup or added via AddTrustedPeer RPC.
@@ -745,60 +712,6 @@ func (srv *Server) run(dialstate dialer) {
 		}
 	}
 
-	// remember and maintain the connection flags locally
-	setConnFlags := func(id enode.ID, f connFlag, val bool) {
-		if p, ok := peers[id]; ok {
-			p.rw.set(f, val)
-		}
-		if val {
-			peerflags[id] |= f
-		} else {
-			peerflags[id] &= ^f
-		}
-		if peerflags[id] == 0 {
-			delete(peerflags, id)
-		}
-	}
-
-	// Put trusted nodes into a map to speed up checks.
-	// Trusted peers are loaded on startup or added via AddTrustedPeer RPC.
-	for _, n := range srv.TrustedNodes {
-		setConnFlags(n.ID(), trustedConn, true)
-	}
-
-	canDisconnect := func(p *Peer) bool {
-		f, ok := peerflags[p.ID()]
-		if ok && f != 0 {
-			return false
-		}
-		return !p.rw.is(dynDialedConn | inboundConn)
-	}
-
-	removeGroup := func(g *dialGroup) {
-		if gg, ok := groups[g.name]; ok {
-			for id := range gg.nodes {
-				groupRefCount[id]--
-				if groupRefCount[id] == 0 {
-					setConnFlags(id, groupDialedConn, false)
-					delete(groupRefCount, id)
-				}
-			}
-		}
-	}
-
-	addGroup := func(g *dialGroup) {
-		if _, ok := groups[g.name]; ok {
-			removeGroup(groups[g.name])
-		}
-		for id := range g.nodes {
-			groupRefCount[id]++
-			if groupRefCount[id] > 0 {
-				setConnFlags(id, groupDialedConn, true)
-			}
-		}
-		groups[g.name] = g
-	}
-
 running:
 	for {
 		scheduleTasks()
@@ -812,16 +725,14 @@ running:
 			// ephemeral static peer list. Add it to the dialer,
 			// it will keep the node connected.
 			srv.log.Trace("Adding static node", "node", n)
-			setConnFlags(n.ID(), staticDialedConn, true)
 			dialstate.addStatic(n)
 		case n := <-srv.removestatic:
 			// This channel is used by RemovePeer to send a
 			// disconnect request to a peer and begin the
 			// stop keeping the node connected.
 			srv.log.Trace("Removing static node", "node", n)
-			setConnFlags(n.ID(), staticDialedConn, false)
 			dialstate.removeStatic(n)
-			if p, ok := peers[n.ID()]; ok && canDisconnect(p) {
+			if p, ok := peers[n.ID()]; ok {
 				p.Disconnect(DiscRequested)
 			}
 		case n := <-srv.adddirect:
@@ -829,42 +740,36 @@ running:
 			// ephemeral direct peer list. Add it to the dialer,
 			// it will keep the node connected.
 			srv.log.Trace("Adding direct node", "node", n)
-			setConnFlags(n.ID(), directDialedConn, true)
-			if p, ok := peers[n.ID()]; ok {
-				p.rw.set(directDialedConn, true)
-			}
 			dialstate.addDirect(n)
 		case n := <-srv.removedirect:
 			// This channel is used by RemoveDirectPeer to send a
 			// disconnect request to a peer and begin the
 			// stop keeping the node connected.
 			srv.log.Trace("Removing direct node", "node", n)
-			setConnFlags(n.ID(), directDialedConn, false)
+			dialstate.removeDirect(n)
 			if p, ok := peers[n.ID()]; ok {
-				p.rw.set(directDialedConn, false)
-				if !p.rw.is(trustedConn | groupDialedConn) {
-					p.Disconnect(DiscRequested)
-				}
+				p.Disconnect(DiscRequested)
 			}
-			dialstate.removeDirect(n)
-		case g := <-srv.addgroup:
-			srv.log.Trace("Adding group", "group", g)
-			addGroup(g)
-			dialstate.addGroup(g)
-		case g := <-srv.removegroup:
-			srv.log.Trace("Removing group", "group", g)
-			removeGroup(g)
-			dialstate.removeGroup(g)
 		case n := <-srv.addtrusted:
 			// This channel is used by AddTrustedPeer to add an enode
 			// to the trusted node set.
 			srv.log.Trace("Adding trusted node", "node", n)
-			setConnFlags(n.ID(), trustedConn, true)
+			trusted[n.ID()] = true
+			// Mark any already-connected peer as trusted
+			if p, ok := peers[n.ID()]; ok {
+				p.rw.set(trustedConn, true)
+			}
 		case n := <-srv.removetrusted:
 			// This channel is used by RemoveTrustedPeer to remove an enode
 			// from the trusted node set.
 			srv.log.Trace("Removing trusted node", "node", n)
-			setConnFlags(n.ID(), trustedConn, false)
+			if _, ok := trusted[n.ID()]; ok {
+				delete(trusted, n.ID())
+			}
+			// Unmark any already-connected peer as trusted
+			if p, ok := peers[n.ID()]; ok {
+				p.rw.set(trustedConn, false)
+			}
 		case op := <-srv.peerOp:
 			// This channel is used by Peers and PeerCount.
 			op(peers)
@@ -879,8 +784,9 @@ running:
 		case c := <-srv.posthandshake:
 			// A connection has passed the encryption handshake so
 			// the remote identity is known (but hasn't been verified yet).
-			if f, ok := peerflags[c.node.ID()]; ok {
-				c.flags |= f
+			if trusted[c.node.ID()] {
+				// Ensure that the trusted flag is set before checking against MaxPeers.
+				c.flags |= trustedConn
 			}
 			// TODO: track in-progress inbound node IDs (pre-Peer) to avoid dialing them.
 			select {
@@ -962,9 +868,9 @@ func (srv *Server) protoHandshakeChecks(peers map[enode.ID]*Peer, inboundCount i
 
 func (srv *Server) encHandshakeChecks(peers map[enode.ID]*Peer, inboundCount int, c *conn) error {
 	switch {
-	case !c.is(trustedConn|staticDialedConn|directDialedConn|groupDialedConn) && len(peers) >= srv.MaxPeers:
+	case !c.is(trustedConn|staticDialedConn|directDialedConn) && len(peers) >= srv.MaxPeers:
 		return DiscTooManyPeers
-	case !c.is(trustedConn|directDialedConn|groupDialedConn) && c.is(inboundConn) && inboundCount >= srv.maxInboundConns():
+	case !c.is(trustedConn|directDialedConn) && c.is(inboundConn) && inboundCount >= srv.maxInboundConns():
 		return DiscTooManyPeers
 	case peers[c.node.ID()] != nil:
 		return DiscAlreadyConnected