WIP

examples/datagram/README.md

+# Datagram protocols with libp2p
+
+This libp2p example is a form of readme-driven development for packet switching.
+I'm using it to test out interfaces and conventions, and also to produce working code.
+
+For now it's going to be the simplest possible echo server/client.
+
+## Additions
+
+package p2phost
+type MsgHandler func(peer.ID, protocol.ID, []byte)
+type Host interface {
+  MsgMux() *msmux.MultigramMuxer
+  SetMsgHandler(protocol.ID, inet.MsgHandler)
+  SetMsgHandlerMatch(protocol.ID, func(string) bool, MsgHandler)
+  RemoveMsgHandler(protocol.ID)
+  WriteMsg(context.Context, peer.ID, ...protocol.ID, []byte)
+}
+
+package p2pswarm
+type MsgHandler func(peer.ID, []byte)
+func (s *Swarm) AddPacketTransport(p2ptransport.PacketTransport) {}
+func (s *Swarm) SetMsgHandler(MsgHandler) {}
+func (s *Swarm) MsgHandler() MsgHandler {}
+
+package p2piconn
+type PacketConn interface {}
+
+package p2pnet
+
+package p2pstream
+func NoOpMsgHandler(msg []byte, peeridOrConn) {}
+
+package p2ptransport
+
+package udptransport
+
+package manet
+
+## TODO
+
+- [ ] go-multiaddr-net datagram support
+- [ ] go-libp2p-transport datagram support
+- [ ] go-udp-transport
+- [ ] go-peerstream datagram support
+- [ ] go-libp2p-swarm datagram support
+- [ ] go-multigram
+- [ ] go-shs vs. go-dtls vs. go-cryptoauth
+- [ ] label-based switch
+- [ ] overlay routing interfaces
+
+
+## PR
+
+This PR adds APIs for message-based communication

examples/datagram/main.go

+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	swarm "github.com/libp2p/go-libp2p-swarm"
+	udpt "github.com/libp2p/go-udp-transport"
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+func fatal(i interface{}) {
+	fmt.Println(i)
+	os.Exit(1)
+}
+
+// XXX unrewritten broken because jbenet/go-stream-muxer is out of date
+// TODO move to libp2p org: go-stream-muxer go-smux-multistream go-smux-spdystream go-smux-yamux
+// TODO multigram will live in BasicHost, for now it's only swarm
+
+func main() {
+	laddr, err := ma.NewMultiaddr("/ip4/0.0.0.0/udp/4737")
+	if err != nil {
+		fatal(err)
+	}
+
+	s := swarm.NewBlankSwarm(context.Background(), "Qmbob", nil, nil)
+	s.AddPacketTransport(udpt.NewUDPTransport())
+
+	// Add an address to start listening on
+	err = s.AddListenAddr(laddr)
+	if err != nil {
+		fatal(err)
+	}
+
+	// Conn as argument, for WriteMsg()?
+	s.SetMsgHandler(func(msg []byte, peerid string) {
+		fmt.Printf("got message from %s: %s\n", peerid, string(msg))
+
+		_, err = s.WriteMsg(msg, peerid)
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
+	})
+
+	s.WriteMsg("hey bob", "Qmbob")
+
+	// Wait forever
+	<-make(chan bool)
+}