N3IWF UE ping DN failed

Q/A
1

I use free5gc n3iwf to link to our core, and use free5gc ue simulator TestNon3GPPUE in non3gpp_test.go, now the ue registration and pdu session establishment is passed, I will do icmp ping to remote DN.
Bu the ping is failed, I see that in TestNon3GPPUE, create gre tunnel 0 interface, and allocate the UE ip to it, and I follow the same method, but looks like invalid.
The ping gtp(icmp) not send out, since I have not capture the ping echo request, I do not know why. I chenged the non3gpp_test.go like this:

// Set GRE interface up
	if err := netlink.LinkSetUp(linkGRE); err != nil {
		t.Fatal(err)
	}
	// Add route
	upRoute := &netlink.Route{
		LinkIndex: linkGRE.Attrs().Index,
		Dst: &net.IPNet{
			IP:   net.IPv4zero,
			Mask: net.IPv4Mask(0, 0, 0, 0),
		},
	}
	t.Logf("#### upRoute: %+v", upRoute)
	if err := netlink.RouteAdd(upRoute); err != nil {
		t.Fatal(err)
	}
	defer func() {
		_ = netlink.LinkSetDown(linkGRE)
		_ = netlink.LinkDel(linkGRE)
	}()
	// Ping remote, remote ip mask is configured in UPF???
	pinger, err := ping.NewPinger("172.20.231.101")
	if err != nil {
		t.Fatal(err)
	}
2

How about provide some pcap file capture from your UE, N3IWF, and UPF?

3

Hi，
please look at the pcap file captured in UEns and host, looks like that the icmp echo reqeust is not received in n3iwf Nwuup: I added some log in below function, but nothing printed out: ReadFrom retur nnothing. UEns.pcap (7.3 KB) default_ns.pcap (447.8 KB) upf.pcap (36.8 KB)
func listenAndServe(rawSocket *ipv4.RawConn) {
defer func() {
err := rawSocket.Close()
if err != nil {
nwuupLog.Errorf(“Error closing raw socket: %+v”, err)
}
}()

          buffer := make([]byte, 65535)

          for {
                         ipHeader, ipPayload, _, err := rawSocket.ReadFrom(buffer)  //here read nothing from gre tunnel interface
                         nwuupLog.Tracef("Read %d bytes", len(ipPayload))
                         if err != nil {
                                       nwuupLog.Errorf("Error read from raw socket: %+v", err)
                                       return
                         }

                         forwardData := make([]byte, len(ipPayload[4:]))
                         copy(forwardData, ipPayload[4:])

                         go forward(ipHeader.Src.String(), forwardData)
          }

}

6

Why the icmp packet on UEns didn’t encapsulate into gtp packet?

4

here is my configuration in UEns and host, ip address and ip link and route:
please help to look at what is my problem:
ip_address_ip_link_route_in_UEns_host.txt (9.0 KB)

5

Any update for this question? Looking forward to your reply

7

another question: I see you use the gtp golang pkg to send the message, WriteToGTP, but not incude the gtp extension header, I want to contains the gtp extension header in gtpu message, since I want to contain the QFI in extension header, How can I change the code? can I change the golang gtp pkg?