Relay (#678)

Co-authored-by: Wade Simmons <wsimmons@slack-corp.com>

udp/conn.go

@@ -9,6 +9,7 @@ const MTU = 9001
 
 type EncReader func(
 	addr *Addr,
+	via interface{},
 	out []byte,
 	packet []byte,
 	header *header.H,

udp/temp.go

@@ -5,10 +5,18 @@ import (
 	"github.com/slackhq/nebula/iputil"
 )
 
-//TODO: The items in this file belong in their own packages but doing that in a single PR is a nightmare
-
 type EncWriter interface {
+	SendVia(via interface{},
+		relay interface{},
+		ad,
+		nb,
+		out []byte,
+		nocopy bool,
+	)
 	SendMessageToVpnIp(t header.MessageType, st header.MessageSubType, vpnIp iputil.VpnIp, p, nb, out []byte)
+	Handshake(vpnIp iputil.VpnIp)
 }
 
+//TODO: The items in this file belong in their own packages but doing that in a single PR is a nightmare
+
 type LightHouseHandlerFunc func(rAddr *Addr, vpnIp iputil.VpnIp, p []byte, w EncWriter)

udp/udp_generic.go

@@ -86,6 +86,6 @@ func (u *Conn) ListenOut(r EncReader, lhf LightHouseHandlerFunc, cache *firewall
 
 		udpAddr.IP = rua.IP
 		udpAddr.Port = uint16(rua.Port)
-		r(udpAddr, plaintext[:0], buffer[:n], h, fwPacket, lhf, nb, q, cache.Get(u.l))
+		r(udpAddr, nil, plaintext[:0], buffer[:n], h, fwPacket, lhf, nb, q, cache.Get(u.l))
 	}
 }

udp/udp_linux.go

@@ -145,7 +145,7 @@ func (u *Conn) ListenOut(r EncReader, lhf LightHouseHandlerFunc, cache *firewall
 		for i := 0; i < n; i++ {
 			udpAddr.IP = names[i][8:24]
 			udpAddr.Port = binary.BigEndian.Uint16(names[i][2:4])
-			r(udpAddr, plaintext[:0], buffers[i][:msgs[i].Len], h, fwPacket, lhf, nb, q, cache.Get(u.l))
+			r(udpAddr, nil, plaintext[:0], buffers[i][:msgs[i].Len], h, fwPacket, lhf, nb, q, cache.Get(u.l))
 		}
 	}
 }

udp/udp_tester.go

@@ -117,7 +117,7 @@ func (u *Conn) ListenOut(r EncReader, lhf LightHouseHandlerFunc, cache *firewall
 		p := <-u.RxPackets
 		ua.Port = p.FromPort
 		copy(ua.IP, p.FromIp.To16())
-		r(ua, plaintext[:0], p.Data, h, fwPacket, lhf, nb, q, cache.Get(u.l))
+		r(ua, nil, plaintext[:0], p.Data, h, fwPacket, lhf, nb, q, cache.Get(u.l))
 	}
 }