error_t enc28j60SendPacket(NetInterface *interface,
   const NetBuffer *buffer, size_t offset, NetTxAncillary *ancillary)
{
   size_t length;

   //Retrieve the length of the packet
   length = netBufferGetLength(buffer) - offset;

   //Check the frame length
   if(length > 1536)
   {
      //The transmitter can accept another packet
      osSetEvent(&interface->nicTxEvent);
      //Report an error
      return ERROR_INVALID_LENGTH;
   }

   //Make sure the link is up before transmitting the frame
   if(!interface->linkState)
   {
      //The transmitter can accept another packet
      osSetEvent(&interface->nicTxEvent);
      //Drop current packet
      return NO_ERROR;
   }

   //It is recommended to reset the transmit logic before
   //attempting to transmit a packet
   enc28j60SetBit(interface, ENC28J60_REG_ECON1, ECON1_TXRST);
   enc28j60ClearBit(interface, ENC28J60_REG_ECON1, ECON1_TXRST);

   //Interrupt flags should be cleared after the reset is completed
   enc28j60ClearBit(interface, ENC28J60_REG_EIR, EIR_TXIF | EIR_TXERIF);

   //Set transmit buffer location
   enc28j60WriteReg(interface, ENC28J60_REG_ETXSTL, LSB(ENC28J60_TX_BUFFER_START));
   enc28j60WriteReg(interface, ENC28J60_REG_ETXSTH, MSB(ENC28J60_TX_BUFFER_START));

   //Point to start of transmit buffer
   enc28j60WriteReg(interface, ENC28J60_REG_EWRPTL, LSB(ENC28J60_TX_BUFFER_START));
   enc28j60WriteReg(interface, ENC28J60_REG_EWRPTH, MSB(ENC28J60_TX_BUFFER_START));

   //Copy the data to the transmit buffer
   enc28j60WriteBuffer(interface, buffer, offset);

   //ETXND should point to the last byte in the data payload
   enc28j60WriteReg(interface, ENC28J60_REG_ETXNDL, LSB(ENC28J60_TX_BUFFER_START + length));
   enc28j60WriteReg(interface, ENC28J60_REG_ETXNDH, MSB(ENC28J60_TX_BUFFER_START + length));

   //Start transmission
   enc28j60SetBit(interface, ENC28J60_REG_ECON1, ECON1_TXRTS);

   //Successful processing
   return NO_ERROR;
}
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.