UDP packets via TSE

Hi, I am working on a project that requires me to send data packets from DE2-115 to a PC. since I need a transfer rate in access of 500 Mbps, i decided to do it using Ethernet using Triple Speed Ethernet IP from altera. But I am facing some problem with the packet fabrication.

what i did

The hardware side of it is very similar to the "using triple-speed ethernet on de2-115 boards" (ftp://ftp.altera.com/up/pub/altera_material/12.0/tutorials/de2-115/using_triple_speed_ethernet.pdf) tutorial. I used TSE and DMA to send data from ethernet. it works fine. I think...

On the software side, I used the tse_tutorial.v provided with the tutorial but changed it arround to make the following changes:

Firstly, I made the following struct to help make ethernet, ip and udp headers

struct etheader {
 unsigned char      preamble;
 unsigned char      MACdestination;
 unsigned char      MACsource;
 unsigned char         proto;
};
struct ipheader {
 unsigned char      iph_type;
 unsigned char      iph_dscp;
 unsigned short int iph_len;
 unsigned short int iph_ident;
 unsigned char      iph_flag;
 unsigned char      iph_offset;
 unsigned char      iph_ttl;
 unsigned char      iph_protocol;
 unsigned short int iph_chksum;
 unsigned char        iph_sourceip;
 unsigned char      iph_destip;
};
// UDP header's structure
struct udpheader {
 unsigned short int    port;
 unsigned short int  udph_len;
 unsigned short int udph_chksum;
};
struct crc32body {
 unsigned int crc_chksum;
 unsigned char end;
};

Then I made the following function to compute the ipchecksum and crc32:

unsigned int crc32c(unsigned char *message, unsigned int last) {
   int i, j;
   unsigned int byte, crc, mask;
   static unsigned int table;
   /* Set up the table, if necessary. */
   if (table == 0) {
      for (byte = 0; byte <= 255; byte++) {
         crc = byte;
         for (j = 7; j >= 0; j--) {    // Do eight times.
            mask = -(crc & 1);
            crc = (crc >> 1) ^ (0xEDB88320 & mask);
         }
         table = crc;
      }
   }
   /* Through with table setup, now calculate the CRC. */
   i = 0;
   crc = 0xFFFFFFFF;
   while ((byte = message) != 0) {
      crc = (crc >> 8) ^ table;
      i = i + 1;
   }
   return ~crc;
}
unsigned short csum(unsigned short *buf, int nwords, int mwords)
{       //
        unsigned short *sht_buf = (buf  + mwords );
        unsigned long sum;
        for(sum=0; nwords>0; nwords--)
                sum += *sht_buf++;
        sum  = (sum >> 16) + (sum &0xffff);
        sum += (sum >> 16);
        return (unsigned short)(~sum);
}
unsigned short int htons(unsigned short int x)
{# if BYTE_ORDER == LITTLE_ENDIAN
        u_char *s = (u_char *) &x;
        return (unsigned short int)(s << 8 | s);# else
        return x;# endif
}

the codes are correct to my understanding.

after initializing the TSE core, I started with the making to the transmission frame:

// frame buffer
unsigned char rx_frame
// size of frame
unsigned frame Tx_UDPpayloadlength = 180
unsigned int total_size = sizeof(struct etheader)+Tx_UDPpayloadlength+
                  sizeof(struct ipheader)+sizeof(struct udpheader) + 0x0004;
// structure the frame
unsigned char MAC_des = {0x78,0x84,0x3c,0xcf,0xf4,0x25};// laptop
unsigned char MAC_src = {0x01,0x60,0x6E,0x11,0x02,0x0F};
unsigned char IP_des = {192,168,0,2};
unsigned char IP_src = {192,168,0,44};
struct etheader *eth = (struct etheader * ) tx_frame;
struct ipheader *ip = (struct ipheader *) (tx_frame  + sizeof(struct etheader) );
struct udpheader *udp = (struct udpheader *) (tx_frame + sizeof(struct etheader)+ sizeof(struct ipheader));
struct crc32body *crc_32b = (struct crc32body *) (tx_frame + sizeof(struct etheader)+
                  sizeof(struct ipheader)+sizeof(struct udpheader) + Tx_UDPpayloadlength);
// Fabricate the ethernet header or we can use the
int lp=0;
       for (lp=0; lp < 2; lp++)    // Ethernet preamble
           eth->preamble = 0x00;
       for (lp=0; lp < 6; lp++)    // Ethernet preamble
       {
          eth->MACsource = MAC_src;
           eth->MACdestination = MAC_des;
           if (lp < 4)
           {
                  ip->iph_sourceip = IP_src;
                  ip->iph_destip = IP_des;
            }
        }
       eth->proto=0x08;
       eth->proto=0x00;
      // Fabricate the IP and UDP header
        ip->iph_type = 0x45;
        ip->iph_dscp = 0x00;
        ip->iph_len = Tx_UDPpayloadlength + sizeof(struct ipheader) + sizeof(struct udpheader);
        ip->iph_ident = 0x0000;
        ip->iph_offset = 0x00;
        ip->iph_flag = 0x00;
        ip->iph_ttl = 0x80;   // time to live
        ip->iph_protocol = 0x11; // UDP = 17
        udp->port=htons(1024);//0x04; udp->port=0x00;
        udp->port=htons(1024);//=0x04; udp->port=0x00;
        //udp->port=htons(1024);
        udp->udph_len=htons(sizeof(struct udpheader)+Tx_UDPpayloadlength);
        udp->udph_chksum=0x0000;
        ip->iph_chksum=csum((unsigned short *)tx_frame, sizeof(struct ipheader) + sizeof(struct udpheader), sizeof(struct etheader) );
        crc_32b->crc_chksum =crc32c(tx_frame, total_size-0x0005);
        crc_32b->end = '\0';

this in should make a frame that send date from 192.168.0.44:1024 to 129.168.0.2:1024. I used tcpdump to validate my packets. This is what I get:

<time> IP truncated-ip - 53035 bytes missing! 192.168.0.44.1024 > 192.168.0.2.1024: UDP, length 180

commands for sending packet:

        alt_avalon_sgdma_construct_mem_to_stream_desc( &tx_descriptor, &tx_descriptor_end, tx_frame, total_size, 0, 1, 1, 0 );
      // Set up non-blocking transfer of sgdma transmit descriptor
        alt_avalon_sgdma_do_async_transfer( sgdma_tx_dev, &tx_descriptor );

TSE settings:

--- Quote Start ---

Select the following options: Enable MAC 10/100 half duplex support, Include statistics counters,Align packet headers to 32-bit boundary, and Include MDIO module (MDC/MDIO),

--- Quote End ---

Maybe someone has experience with this to know where I am going wrong!