Ethernet to serial converter using TM4C129EXL

Question

I need help regarding the lwip stack with tiva c, I am building UDP to serial converter, the function is working correctly, but I have some concerns:

1. When I receive the UDP packet buffer, I directly echoed it back if UART is busy sending the previous UDP, is this correct because I am not sure what is the type of the allocated buffer?
2. When UART is not sending, I put the data on array and send it to the UART function, is there any other efficient way to perform this ? i.e using ring buffer or any other techniques?

the code for udp callback function for receiving packets:

void Udp_Receive(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port) {

uint8_t *pui8Data;
uint32_t ui32Idx;

//
// If packet more than 128 bytes drop it
//
if((p->len) > 128)
  {
    pbuf_free(p);
    return;
  }

//
// check UART and if it is sending just echo the UDP
//
if(uart_status == 1 )
{
       //
       // Send the echoed message.
       //
       udp_sendto(pcb, p, addr, 1234);
       pbuf_free(p);
}
else
{
    //
    // Received Packet information and send it to serial
    //
    udp_length = (p->len);
    pui8Data = p->payload;
    udp_to_serial_counter++;
    //
    // clear the payload array to receive new one.
    //
    for(ui32Idx = 0; ui32Idx < udp_length ; ui32Idx++)
       {
        udp_payload[ui32Idx] = 0;
        }
    //
    // fill the payload from buf into the array
    //
    for(ui32Idx = 0; ui32Idx < udp_length ; ui32Idx++)
       {
        udp_payload[ui32Idx] = pui8Data[ui32Idx];
       }

    pbuf_free(p);
     //
     // Allocate a new pbuf for sending the response.
     //
     p = pbuf_alloc(PBUF_TRANSPORT,udp_length, PBUF_RAM);
     if(p == NULL)
     {
         return;
     }
     //
     // Copy the the received  packet payload into  the udp_payload
     //
     p->payload = udp_payload ;
     p->len = udp_length ;
     //
     // Send the echoed message.
     //
     udp_sendto(pcb, p, addr, 1234);
     pbuf_free(p);
     set_uart_send_status();

}

The uart send function is :

UARTSend( uint8_t *pui8Buffer, uint32_t ui32Count) { // Loop while there are more characters to send. while(ui32Count--) {

     while(!(ROM_UARTSpaceAvail(UART6_BASE)));

     ROM_UARTCharPutNonBlocking(UART6_BASE, *pui8Buffer++);  

   }
          while((ROM_UARTBusy(UART6_BASE)));

}