topic Re: UPD Packets via uIP in LPCXpresso IDE

UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:23 GMT

Content originally posted in LPCWare by DiamondS on Fri Nov 25 01:38:02 MST 2011
Hi,

I have a problem, cant send UDP packets via uIP TCP/IP Stack.
Maybe someone can share a small example of how to do it?
Because on Wireshark i cant see any of packets, when i send UDP.
I use uIP RBD1768 DHCP example. Everything is working.

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:24 GMT

Content originally posted in LPCWare by Ex-Zero on Fri Nov 25 05:17:36 MST 2011
What about sample in #7 of http://knowledgebase.nxp.com/showthread.php?p=10903

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:24 GMT

Content originally posted in LPCWare by Ex-Zero on Sat Nov 26 08:04:37 MST 2011

Quote: DiamondS
I have a problem, cant send UDP packets via uIP TCP/IP Stack.
Maybe someone can share a small example of how to do it?

[INDENT] Transmitting Ethernet frames is very easy :rolleyes:

Just use tapdev_send() to transmit your ethernet frame :eek:

Unfortunately creating a valid ethernet frame isn't as easy :mad:, so I've copied you my 'sample' frame. Just include it in your main and use 'send_UDP_frame()'.

It's assembling an ethernet frame and transmitting a valid 64 byte UDP.

Since this is a valid frame, Wireshark has no problems to show it

[/INDENT]

//Creating a simple ethernet structure and transmit a valid UDP 

//source IP
#define S_IP1         192
#define S_IP2         168
#define S_IP3         178
#define S_IP4         20

//dest IP
#define D_IP1         192
#define D_IP2         168
#define D_IP3         178
#define D_IP4         26

struct ip_eth_addr {
  u8_t addr[4];
};

struct ip_eth_addr s_ip = { {S_IP1, S_IP2, S_IP3, S_IP4}};
struct ip_eth_addr d_ip = { {D_IP1, D_IP2, D_IP3, D_IP4}};

struct uip_eth_addr mymac = { {MYMAC_1, MYMAC_2, MYMAC_3, MYMAC_4, MYMAC_5, MYMAC_6} } ;
char ipstring [20];

#define BUF ((struct uip_eth_hdr *)&uip_buf[0])

void* first_data_byte;

//define ethernet II header
struct eth_header
{
//ether frame
 uint8_t  ether_dest[6];            //destination mac address
 uint8_t  ether_src[6];                //source mac address
 uint16_t ether_type;                //ether type
//ip frame
 uint8_t vhl;//version / IHL
 uint8_t tos;//type of service
 uint16_t len;//len
 uint16_t ipid;
 uint16_t ipoffset;
 uint8_t  ttl;
 uint8_t  proto;
 uint16_t ipchksum;
 uint16_t srcipaddr[2];
 uint16_t destipaddr[2];
//udp
 uint16_t srcport;
 uint16_t destport;
 uint16_t udplen;
 uint16_t udpchksum;
 };

//struct eth_header frame;
#define frame ((struct eth_header*)&uip_buf[0])
unsigned char frame_counter;
unsigned int test_counter;
char test1[] = "TEST";
unsigned int data_len = 64;            //udp data len

void send_UDP_frame(void)
{
 frame_counter++;
 uip_len = sizeof(struct eth_header);    //get struct header len = 42
 memset(frame->ether_dest, 0xff, 6);    //0xff = broadcast
 memcpy(frame->ether_src, &mymac, 6);
 frame->ether_type = HTONS(0x0800);        //IP following
 frame->vhl           = 0x45;                //IP4, 20byte header
 frame->tos           = 0x00;                //
 frame->len        = HTONS(28 + data_len);
 frame->ipid       = HTONS(frame_counter);//
 frame->ipoffset   = HTONS(0);
 frame->ttl        = 0x80;            //time to live
 frame->proto        = 0x11;            //UDP (17)
 frame->ipchksum   = 0;                //reset checksum (will be calculated and inserted later)
 memcpy(frame->srcipaddr, &s_ip,4); //insert source ip
 memcpy(frame->destipaddr,&d_ip,4); //insert dest ip
//calculate IP4 header checksum
 frame->ipchksum=~uip_chksum((uint16_t*)&uip_buf[14],20); //20 byte header checksum
 frame->srcport     = HTONS(1024);    //source port
 frame->destport    = HTONS(1023);    //destination port
 frame->udplen        = HTONS(data_len+8);    //data len + 8 byte udp header
 first_data_byte = &uip_buf[uip_len];    //data section of frame 0x2A = 42
 memcpy(first_data_byte, &test1, 4);//copy string
 memcpy(first_data_byte+0x10, &test_counter, 2);//copy data
 test_counter +=8;                    //change test counter
//transmit buffer
 tapdev_send(uip_buf,uip_len+data_len);
}

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:25 GMT

Content originally posted in LPCWare by DiamondS on Mon Nov 28 07:46:18 MST 2011
Your example is working.
But i wondering, what for are these functions: uip_udp_conn, uip_udp_remove, uip_udp_bind uip_udp_send.
There is also similar structure as eth_header - uip_udpip_hdr.

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:25 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 09:04:48 MST 2012
Zero, do you have a simple example for receiving UDP as well?
I have been trying to just use the tapdev_read(recbuff);
But I seem to get hard faults.
Any help here would be appreciated

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:26 GMT

Content originally posted in LPCWare by Ex-Zero on Sun Mar 18 10:48:32 MST 2012
Reading with:

//receive packet and put in uip_buf 
uip_len = tapdev_read(uip_buf);
if(uip_len > 0)        // received packet 
{
 if(BUF->type == HTONS(UIP_ETHTYPE_IP))    // IP packet 
 {
  if(frame->proto == 0x11)        //UDP (17) ?
  {
   memcpy(&test,&uip_buf[42 + 0x10], 2); //copy value from data behind header (42 bytes)
   printf("Test: %5d\n",test);   //printf via semihosting
  }                                //end UDP
 }                                //end IP
}                                //end received packet

is no problem here

Did you use Wireshark to check your transmitted packet?

Did you check MAC address, source ip, destination ip, source port and destination port?

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:26 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 11:21:17 MST 2012
Thanks, that seems to get the packets. But it looks like I am getting all network packets with that. And my hard fault seems to be caused by using printf to view the packets..

I have the dest ip and source ip correct and I can see packets when sending with the lpcxpresso on wire shark.

I am guessing that I have to filter the incoming packets some how by the IP header in the packet?

Here is the receive code so far (with the printf problem)

uip_reclength = tapdev_read(recbuff);
            if(uip_reclength > 0)
            {
                printf(recbuff);
            }

I am using the newlib with semihosting.

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:27 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 11:25:55 MST 2012
One more question, I see that the emac address is defined in lpc17xx_emac.h
Does this set the mac address of the lpc to anything that I want or does each lpc have its own unique address that I need to find?

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:27 GMT

Content originally posted in LPCWare by Ex-Zero on Sun Mar 18 11:36:25 MST 2012

Quote: Dave3891
Thanks, that seems to get the packets. But it looks like I am getting all network packets with that.

I've added an UDP check below :)

Quote: Dave3891
And my hard fault seems to be caused by using printf to view the packets..

Printing 1538 bytes could be a problem :rolleyes:

You should copy desired bytes to your values as added below :)

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:28 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 11:46:49 MST 2012
Thanks!

How large should my receive buffer be?
The header is 42 bytes and 64 for data, so will a 128 byte receive buffer be more then enough?

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:29 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 12:05:03 MST 2012
I still seem to get a hard fault for some reason.
I am using redlib semihosting and with just a simple message

if(timer_expired(&periodic_timer))
        {
            send_UDP_frame();
            printf("test data sent  \n");
              timer_reset(&periodic_timer);

          }

It still gives a hard fault, but it will run for about 20 sends then fault...

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:29 GMT

Content originally posted in LPCWare by Ex-Zero on Sun Mar 18 12:29:57 MST 2012

Quote: Dave3891
How large should my receive buffer be?
The header is 42 bytes and 64 for data, so will a 128 byte receive buffer be more then enough?

How large is your Maximum Frame Register (MAXF - 0x5000 0014)?

User manual:

Quote:

This field resets to the value 0x0600, which represents a maximum receive frame of 1536 octets.

So I would strongly recommend to use a buffer with at least 1536 bytes :rolleyes:

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:30 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 18:25:31 MST 2012
Another question on the receive part of this.
Should I set the RxFilterCtrl to use the AcceptPerfectEn filter so that I don't see all the traffic on the network and only get packets sent for the LPC?

And should I just poll the RxStatus register to see if there is new data available or is there a interrupt for new data received?
If I am polling, will the data over write if I don't get it in time?

Thank you for all the help with this UDP / Ethernet stuff!

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:30 GMT

Content originally posted in LPCWare by Dave3891 on Sun Mar 18 19:36:39 MST 2012

Quote:
Should I set the RxFilterCtrl to use the AcceptPerfectEn filter so that I don't see all the traffic on the network and only get packets sent for the LPC?

Well I figured this part out. I edited the lpc17xx_emac.c and changed the LPC_EMAC->RxFilterCtrl line and the LPC_EMAC->Control line so only the packets with the right address will get passed to the chip.
That part seems to work well now.

Now I just need to search about using interrupts when new rx data is present...

Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:31 GMT

Content originally posted in LPCWare by Ex-Zero on Mon Mar 19 04:20:22 MST 2012
Reading EMAC RxD Interrupt is working fine here

volatile uint16_t flag_EMAC_rxd;        //EMAC read flag

//EMAC interrupt
void ENET_IRQHandler(void)
{
 uint32_t status;
 status =  LPC_EMAC->IntStatus;            //read EMAC interrupt
 if(status & INT_RX_DONE)                //RxD interrupt
 {
  flag_EMAC_rxd =1;                        //set receive flag
  LPC_EMAC->IntClear  = INT_RX_DONE;    //reset interrupt
 }                                        //end RxD interrupt
}

Changed init:

...
//enable EMAC RxD interrupt
    LPC_EMAC->IntEnable = INT_RX_DONE;
//reset EMAC interrupts
    LPC_EMAC->IntClear  = 0xFFFF;
//enable EMAC Interrupt
    NVIC_EnableIRQ(ENET_IRQn);
...

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:31 GMT

Content originally posted in LPCWare by Dave3891 on Tue Mar 20 20:37:16 MST 2012
I am still having a bit of problems sending a packet from the LPC.
I am using netshark and it seems to show a valid packet being sent on the network, but I am not able to receive it on my PC.
I am running UDP test tool to view the packets, but nothing shows up.

I have also made a python script on my linux machine to test sending a UDP packet to the PC and when I do this UDP test tool sees the packet from the linux machine, but still not the LPC and they are both using the same port to send on.

I am guessing that something is making the packet not valid some how...

Any idea's or have you seen this problem before?

Thanks
Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:32 GMT

Content originally posted in LPCWare by Dave3891 on Tue Mar 20 20:52:19 MST 2012
I have also tried a receive script in python on the linux box, and it does not see the packets from the LPC either, but it will see packets from UDP test tool on the windows machine...

I am attaching my main.c

Thanks
Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:33 GMT

Content originally posted in LPCWare by Ex-Zero on Wed Mar 21 03:41:56 MST 2012
Try

frame->len        = HTONS(28 + data_len);

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:33 GMT

Content originally posted in LPCWare by Dave3891 on Wed Mar 21 05:47:46 MST 2012
Works great now! Thanks

Will using 28 always work or is it a temporary fix?

Thanks again
Dave

Re: UPD Packets via uIP

lpcware — Thu, 16 Jun 2016 01:29:34 GMT

Content originally posted in LPCWare by Ex-Zero on Wed Mar 21 06:28:20 MST 2012

Quote: Dave3891
Will using 28 always work or is it a temporary fix?

I've just decided that this will work always :rolleyes: I like this 28 :)

Back to business: 28 is the correct value. Wireshark and other LPC don't care about wrong len values and therefore don't complain :)