learning.go

package switching

import (
	bh "github.com/kandoo/beehive"
	"github.com/1995parham/flynest/nom"
	"github.com/kandoo/beehive/Godeps/_workspace/src/github.com/golang/glog"
)

type LearningSwitch struct {
	Hub
}

func (h LearningSwitch) Rcv(msg bh.Msg, ctx bh.RcvContext) error {
	in := msg.Data().(nom.PacketIn)
	src := in.Packet.SrcMAC()
	dst := in.Packet.DstMAC()
	glog.V(2).Infof("received packet in from %v to %v", src, dst)
	if dst.IsLLDP() {
		// TODO(soheil): just drop LLDP.
		glog.Infof("dropped LLDP packet to %v", dst)
		return nil
	}

	if dst.IsBroadcast() || dst.IsMulticast() {
		return h.Hub.Rcv(msg, ctx)
	}

	d := ctx.Dict("mac2port")
	srck := src.Key()
	update := false
	if v, err := d.Get(srck); err == nil {
		p := v.(nom.UID)
		if p != in.InPort {
			update = true
			// TODO(soheil): maybe add support for multi ports.
			glog.Infof("%v is moved from port %v to port %v", src, p, in.InPort)
		}
	} else {
		update = true
	}

	if update {
		if err := d.Put(srck, in.InPort); err != nil {
			glog.Fatalf("cannot serialize port: %v", err)
		}
	}

	dstk := dst.Key()
	v, err := d.Get(dstk)
	if err != nil {
		return h.Hub.Rcv(msg, ctx)
	}
	p := v.(nom.UID)

	add := nom.AddFlowEntry{
		Flow: nom.FlowEntry{
			Node: in.Node,
			Match: nom.Match{
				Fields: []nom.Field{
					nom.EthDst{
						Addr: dst,
						Mask: nom.MaskNoneMAC,
					},
				},
			},
			Actions: []nom.Action{
				nom.ActionForward{
					Ports: []nom.UID{p},
				},
			},
		},
	}
	ctx.Reply(msg, add)

	out := nom.PacketOut{
		Node:     in.Node,
		InPort:   in.InPort,
		BufferID: in.BufferID,
		Packet:   in.Packet,
		Actions: []nom.Action{
			nom.ActionForward{
				Ports: []nom.UID{p},
			},
		},
	}
	ctx.Reply(msg, out)
	return nil
}

// RegisterSwitch registers the learning switch application on the given
// hive with the provided options.
func RegisterSwitch(h bh.Hive, opts ...bh.AppOption) {
	app := h.NewApp("Switch", opts...)
	app.Handle(nom.PacketIn{}, LearningSwitch{})
}