Adding BGP update sender

protocols/bgp/server/update_sender.go

+package server
+
+import (
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/bio-routing/bio-rd/net"
+	"github.com/bio-routing/bio-rd/protocols/bgp/packet"
+	"github.com/bio-routing/bio-rd/rt"
+)
+
+type UpdateSender struct {
+	fsm *FSM
+}
+
+func newUpdateSender(fsm *FSM) *UpdateSender {
+	return &UpdateSender{
+		fsm: fsm,
+	}
+}
+
+func (u *UpdateSender) AddPath(route *rt.Route) {
+	log.Warningf("BGP Update Sender: AddPath not implemented")
+
+	update := &packet.BGPUpdate{
+		PathAttributes: &packet.PathAttribute{
+			TypeCode: packet.OriginAttr,
+			Value:    uint8(packet.IGP),
+			Next: &packet.PathAttribute{
+				TypeCode: packet.ASPathAttr,
+				Value: packet.ASPath{
+					{
+						Type: 2,
+						ASNs: []uint32{15169, 3329},
+					},
+				},
+				Next: &packet.PathAttribute{
+					TypeCode: packet.NextHopAttr,
+					Value:    [4]byte{100, 110, 120, 130},
+				},
+			},
+		},
+		NLRI: &packet.NLRI{
+			IP:     route.Prefix().Addr(),
+			Pfxlen: route.Pfxlen(),
+		},
+	}
+
+	updateBytes, err := update.SerializeUpdate()
+	if err != nil {
+		log.Errorf("Unable to serialize BGP Update: %v", err)
+		return
+	}
+	fmt.Printf("Sending Update: %v\n", updateBytes)
+	u.fsm.con.Write(updateBytes)
+}
+
+func (u *UpdateSender) ReplaceRoute(*rt.Route) {
+	log.Warningf("BGP Update Sender: ReplaceRoute not implemented")
+}
+
+func (u *UpdateSender) RemovePath(*rt.Route) {
+	log.Warningf("BGP Update Sender: RemovePath not implemented")
+}
+
+func (u *UpdateSender) RemoveRoute(*net.Prefix) {
+	log.Warningf("BGP Update Sender: RemoveRoute not implemented")
+}