Function makeUDP4PacketBuffer

wgengine/netstack/netstack_test.go:1377–1413

(src, dst netip.AddrPort)

}

func makeUDP4PacketBuffer(src, dst netip.AddrPort) *stack.PacketBuffer {
	if !src.Addr().Is4() || !dst.Addr().Is4() {
		panic("src and dst must be IPv4")
	}

	data := []byte("hello world\n")

	packetLen := header.IPv4MinimumSize + header.UDPMinimumSize
	pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
		ReserveHeaderBytes: packetLen,
		Payload:            buffer.MakeWithData(data),
	})

	// Initialize the UDP header.
	udp := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
	pkt.TransportProtocolNumber = header.UDPProtocolNumber

	length := uint16(pkt.Size())
	udp.Encode(&header.UDPFields{
		SrcPort: src.Port(),
		DstPort: dst.Port(),
		Length:  length,
	})

	// Add IP header
	ipHdr := header.IPv4(pkt.NetworkHeader().Push(header.IPv4MinimumSize))
	pkt.NetworkProtocolNumber = header.IPv4ProtocolNumber
	ipHdr.Encode(&header.IPv4Fields{
		TotalLength: uint16(packetLen),
		Protocol:    uint8(header.UDPProtocolNumber),
		SrcAddr:     tcpip.AddrFrom4(src.Addr().As4()),
		DstAddr:     tcpip.AddrFrom4(dst.Addr().As4()),
		Checksum:    0,
	})

	return pkt
}

func makeUDP6PacketBuffer(src, dst netip.AddrPort) *stack.PacketBuffer {
	if !src.Addr().Is6() || !dst.Addr().Is6() {