TUN-8640: Add ICMP support for datagram V3

Closes TUN-8640

quic/v3/icmp_test.go

@@ -0,0 +1,45 @@
+package v3_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/cloudflare/cloudflared/ingress"
+	"github.com/cloudflare/cloudflared/packet"
+)
+
+type noopICMPRouter struct{}
+
+func (noopICMPRouter) Request(ctx context.Context, pk *packet.ICMP, responder ingress.ICMPResponder) error {
+	return nil
+}
+func (noopICMPRouter) ConvertToTTLExceeded(pk *packet.ICMP, rawPacket packet.RawPacket) *packet.ICMP {
+	return nil
+}
+
+type mockICMPRouter struct {
+	recv chan *packet.ICMP
+}
+
+func newMockICMPRouter() *mockICMPRouter {
+	return &mockICMPRouter{
+		recv: make(chan *packet.ICMP, 1),
+	}
+}
+
+func (m *mockICMPRouter) Request(ctx context.Context, pk *packet.ICMP, responder ingress.ICMPResponder) error {
+	m.recv <- pk
+	return nil
+}
+func (mockICMPRouter) ConvertToTTLExceeded(pk *packet.ICMP, rawPacket packet.RawPacket) *packet.ICMP {
+	return packet.NewICMPTTLExceedPacket(pk.IP, rawPacket, testLocalAddr.AddrPort().Addr())
+}
+
+func assertICMPEqual(t *testing.T, expected *packet.ICMP, actual *packet.ICMP) {
+	if expected.Src != actual.Src {
+		t.Fatalf("Src address not equal: %+v\t%+v", expected, actual)
+	}
+	if expected.Dst != actual.Dst {
+		t.Fatalf("Dst address not equal: %+v\t%+v", expected, actual)
+	}
+}