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How to use NDK to get the remote MAC?

brenden lai
Intellectual 380 points
Other Parts Discussed in Thread: SYSBIOS

Hi all ,

Did NDK get remote MAC while remote host issue a udp request ? I try to dump the arp static table while the udp packet proccessing .

I find that there is no arp entry in the table . see code

linux seems to have the function that add a arp entry when it receives a request . Can NDK do that ? Because I need to query the remote mac on arp table or there is any other way to get remote MAC?

Brenden

  • 0
    TI__Expert 4125 points

    Brenden,

    You want to examine the dynamic ARP table, not the static table. There is not a direct function to obtain a MAC address for an IP address, but you can see an example of how to do it in the console example application. See the DumpRouteTable() function in the tools/console/conroute.c source file. You could refactor this function to do what you need.

    Mark

  • 0 in reply to MarkGrosen
    Intellectual 380 points

    Mark , 

            I try use DumpRouteTable() to dig out how to get remote mac ! But fail ! I can not get mac neither remote nor local mac!

            Because of  RtGetLLI return  0 and  LLIGetMacAddr failed ! See below code 2047.empty.c

    if( !(hLLI = RtGetLLI( hRt )) || !LLIGetMacAddr( hLLI, MacAddr, 6 ) )
       llExit(); // can't get hLLI object , so  always there
    else
    {
    llExit();
    System_printf( " %02X:%02X:%02X:%02X:%02X:%02X",
    MacAddr[0], MacAddr[1], MacAddr[2],
    MacAddr[3], MacAddr[4], MacAddr[5] );
    }

    The DumpRouteTable function seems to just can get routing entry not the arp entry !

    Is there any other way to get arp entry?

    Brenden

  • 0 in reply to brenden lai
    TI__Expert 4125 points

    Brenden,

    When I tried using this code, I made the mistake of not defining a critical pre-processor symbol when compiling which led to bad results. Make sure you have -D_INCLUDE_NIMU_CODE defined for the compiler. When I do this, I get (as an example):

    Address Subnet Mask Flags Gateway
    --------------- --------------- ------ -----------------
    0.0.0.0 0.0.0.0 UG xxx.252.160.1
    xxx.252.160.0 255.255.254.0 U C if-1
    xxx.252.161.26 255.255.255.255 U H L local (if-1)
    xxx.252.161.51 255.255.255.255 U H D4:BE:D9:03:11:B3

    Mark

  • 0 in reply to MarkGrosen
    Intellectual 380 points

    Thanks Mark, 

           I'll follow your advice.

    Brenden

  • 0 in reply to MarkGrosen
    Intellectual 380 points

    Hi Mark, 

              I am sure the orignal  NDK already include nimu relate function . I can see nimu relate function symbol in map file (ex:0001410d NIMUPacketServiceCheck) , I can get local mac by call NIMUIoctl() also.But follow your advice I still can't get remote mac by using  LLIGetMacAddr ! It return 0 which means fail!

    Could you see my code is anything wrong ?0447.empty.c2843.empty.cfg

    I am using

    mcusdk version :1_00_00_68 

    CCS version 5.2.0.00069

    ndk version : 2_21_01_38

    sysbios version :6_33_04_39 

    xdctools version :3_23_04_60

    target board : DK_LM3S9d96


    Thank you !

    Brenden

     

  • 0 in reply to brenden lai
    TI__Guru* 96960 points

    Hi Brendan,

    Did you rebuild your app code with the compiler define that Mark mentioned, or did you rebuild the NDK? I believe you need to add this define and rebuild your code.

    Todd

  • 0 in reply to ToddMullanix
    Intellectual 380 points

    Hi Todd , 

             I already add _INCLUDE_NIMU_CODE define , but use LLIGetMacAddr() still fail ! see pic

    Here is my project zip , Can somebody help me to point out what is going on ?http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/355/8032.NDK3.7z

    Brenden

  • 0 in reply to brenden lai
    TI__Guru* 96960 points

    Hi Brenden,

    I've attached a file that I validated with the tcpEcho example in MCUSDK. Can you add this file to your tcpEcho project and rebuild? Note: I add #define _INCLUDE_NIMU_CODE at the top of the arp.c file, so you don't need the compiler option. 

    3323.arp.c

    I call DumpRouteTable() near the top of the tcpWorker. So when you run the linux/windows tcpSendReceive tool, the DumpRouteTable is called.

    Void tcpWorker(UArg arg0, UArg arg1)
    {
    ...

        fdOpenSession(TaskSelf());
        
        DumpRouteTable();

    Here is the output I obtained

    [Cortex_M3_0] Service Status: DHCPC    : Enabled  :          : 000
    [Cortex_M3_0] Service Status: DHCPC    : Enabled  : Running  : 000
    [Cortex_M3_0] Network Added: If-1:146.252.161.13
    [Cortex_M3_0] Service Status: DHCPC    : Enabled  : Running  : 017
    [Cortex_M3_0]  
    [Cortex_M3_0] Address          Subnet Mask      Flags   Gateway
    [Cortex_M3_0] ---------------  ---------------  ------  -----------------
    [Cortex_M3_0] 0.0.0.0          0.0.0.0          UG      146.252.160.1     
    [Cortex_M3_0] 146.252.160.0    255.255.254.0    U   C   if-1
    [Cortex_M3_0] 146.252.161.13   255.255.255.255  U H  L  local (if-1)
    [Cortex_M3_0] 146.252.161.150  255.255.255.255  U H     00:1E:4F:BB:A9:66
    [Cortex_M3_0]  

    Todd

  • 0 in reply to ToddMullanix
    Intellectual 380 points

    Thanks Todd !

    It work!