Method Tun

integration/harness.go:392–433

(node state.NodeId)

}

func (i *InMemoryNetwork) Tun(node state.NodeId) tun.Device {
	i.Lock()
	defer i.Unlock()
	const (
		ipv4Size = 20
	)
	bt := tuntest.NewChannelTUN()

	numId := slices.IndexFunc(i.cfg.Central.Routers, func(cfg state.RouterCfg) bool {
		return cfg.Id == node
	})

	i.virtTun[numId] = bt
	go func() {
		i.WaitForReady()
		for {
			select {
			case <-i.cfg.Context.Done():
				return
			case pkt := <-bt.Inbound:
				// wireguard doesn't actually verify checksum for ip
				ip := pkt[0:ipv4Size]
				if pkt[0]>>4 != 4 {
					panic("unexpected packet, not ipv4")
				}
				var src, dst netip.Addr
				err := src.UnmarshalBinary(ip[12:16])
				if err != nil {
					panic(err)
				}
				err = dst.UnmarshalBinary(ip[16:20])
				if err != nil {
					panic(err)
				}
				if !i.virtualRouteTable(node, src, dst, pkt[ipv4Size:], pkt) {
					panic(fmt.Sprintf("unhandled packet src: %v, dst: %v", src, dst))
				}
			}
		}
	}()
	return bt.TUN()
}

func (i *InMemoryNetwork) Send(node state.NodeId, src, dst string, pkt []byte, ttl byte) {
	const (