EK-TM4C1294XL: How to divert SendBOOTPRequest

Hi Muneto-san,

  Can you please refer to the:

  uip.h and uip.c files in the C:\ti\TivaWare_C_Series-2.2.0.295\third_party\uip-1.0\uip directory 

  dhcpc.c in C:\ti\TivaWare_C_Series-2.2.0.295\third_party\uip-1.0\apps\dhcpc directory

Here you will find how uip_data is declared (in uip.h file) and how it is used in dhcpc.c file. Please also refer to the description in uip.c file. See below. 

/*
* uIP is a small implementation of the IP, UDP and TCP protocols (as
* well as some basic ICMP stuff). The implementation couples the IP,
* UDP, TCP and the application layers very tightly. To keep the size
* of the compiled code down, this code frequently uses the goto
* statement. While it would be possible to break the uip_process()
* function into many smaller functions, this would increase the code
* size because of the overhead of parameter passing and the fact that
* the optimizer would not be as efficient.
*
* The principle is that we have a small buffer, called the uip_buf,
* in which the device driver puts an incoming packet. The TCP/IP
* stack parses the headers in the packet, and calls the
* application. If the remote host has sent data to the application,
* this data is present in the uip_buf and the application read the
* data from there. It is up to the application to put this data into
* a byte stream if needed. The application will not be fed with data
* that is out of sequence.
*
* If the application wishes to send data to the peer, it should put
* its data into the uip_buf. The uip_appdata pointer points to the
* first available byte. The TCP/IP stack will calculate the
* checksums, and fill in the necessary header fields and finally send
* the packet back to the peer.
*/

Snippet of how uip_appdata is declared.

void *uip_appdata; /* The uip_appdata pointer points to
application data. */

Snippet of how uip_appdata is assigned and used in the dhcpc.c file for sending a DISCOVERY packet. 

/*---------------------------------------------------------------------------*/
static void
send_discover(void)
{
u8_t *end;
struct dhcp_msg *m = (struct dhcp_msg *)uip_appdata;

create_msg(m);

end = add_msg_type(&m->options[4], DHCPDISCOVER);
end = add_req_options(end);
end = add_end(end);

uip_send(uip_appdata, end - (u8_t *)uip_appdata);
}

You can also find examples on how uip_appdata is used to send TFTP packets in C:\ti\TivaWare_C_Series-2.2.0.295\third_party\uip-1.0\apps\telnetd\telnetd.c file. 

static void
senddata(void)
{
static char *bufptr, *lineptr;
static int buflen, linelen;

bufptr = uip_appdata;
buflen = 0;
for(s.numsent = 0; s.numsent < TELNETD_CONF_NUMLINES &&
s.lines[s.numsent] != NULL ; ++s.numsent) {
lineptr = s.lines[s.numsent];
linelen = strlen(lineptr);
if(linelen > TELNETD_CONF_LINELEN) {
linelen = TELNETD_CONF_LINELEN;
}
if(buflen + linelen < uip_mss()) {
memcpy(bufptr, lineptr, linelen);
bufptr += linelen;
buflen += linelen;
} else {
break;
}
}
uip_send(uip_appdata, buflen);