TAP -> TUN, handle multiple peers behind one NAT

client/main.go

@@ -16,6 +16,7 @@ import (
 	"github.com/songgao/water"
 )
 
+// TODO: parse some sort of config+key file
 const (
 	SERVER_IP  = "172.20.12.47"
 	IFACE_NAME = "baalvpn"
@@ -69,13 +70,14 @@ func register() {
 	}
 	pubKey := privKey.PublicKey()
 
+	// TODO: this probably should be repeated until we get RESP_REGISTER
 	send(shared.BuildPkt(shared.REQ_REGISTER, pubKey.Bytes()))
 }
 
 func receivePackets() {
+	buffer := make([]byte, 50000)
 	for {
-		buffer := make([]byte, 50000)
-		n, addr, err := conn.ReadFromUDP(buffer)
+		n, addr, err := conn.ReadFromUDP(buffer[:])
 		if err != nil {
 			log.Println(err)
 			continue
@@ -88,7 +90,9 @@ func receivePackets() {
 			continue
 		}
 
-		go handleIncomingPkt(buffer[:n])
+		req := make([]byte, n)
+		copy(req, buffer[:n])
+		go handleIncomingPkt(req)
 	}
 }
 
@@ -195,6 +199,7 @@ func getOrEstablishSessionKey(ip string) []byte {
 	}
 
 	// TODO: this definitely shouldnt block the main thread
+	// TODO: this should try like 10 times tops since server doesnt respond at all if it doesnt have the pubkey
 	for {
 		// request pubkey every 50ms
 		time.Sleep(50 * time.Millisecond)
@@ -233,7 +238,7 @@ func getOrEstablishSessionKey(ip string) []byte {
 }
 
 func setupInterface() {
-	config := water.Config{DeviceType: water.TAP}
+	config := water.Config{DeviceType: water.TUN}
 	config.Name = IFACE_NAME
 
 	var err error
@@ -261,16 +266,14 @@ func relayPackets() {
 		}
 		pkt = pkt[:n]
 
-		etherType := binary.BigEndian.Uint16(pkt[12:14])
-		payload := pkt[14:]
-
-		if etherType != 0x86dd { // IPv6
+		version := pkt[0] >> 4
+		if version != 6 {
 			continue
 		}
 
-		destIP := net.IP(payload[24:40]).String()
+		destIP := net.IP(pkt[24:40]).String()
 
-		if payload[24] == 0xff { // multicast
+		if pkt[24] == 0xff { // multicast
 			encryptedPkt, err := EncryptSym(multicastKey, pkt)
 			if err != nil {
 				panic(err)