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 Robotics / RCX / legOS / 2803
2802  |  2804
Subject: 
Re: lnp addressing messages
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Tue, 27 Aug 2002 11:56:03 GMT
Viewed: 
2045 times
  
nanobapt wrote:

and how to configure address of computer ?


Martin Cornelius wrote a nice little piece on this and related isues. it can be
found at:
http://news.lugnet.com/robotics/rcx/legos/?n=788
in particular look for the sentence:
. Can the host set its source address? If so, how?
and all shall be revealed :)


taken from luis villas legOS howto i initialize lnp on the PC with:

if(lnp_init(0,0,0,0,0)){
        perror("lnp_init\n");
        exit(1);
}else{
        fprintf(stderr,"init Ok\n");
}

thus if you want to change the address of the PC you will have to change the
third parameter to the lnp_init function call.
f.eks:
if(lnp_init(0,0,1,0,0)){
        perror("lnp_init\n");
        exit(1);
}else{
        fprintf(stderr,"init Ok\n");
}

would set the address of the PC to 0x10.

from left to right the parameters to lnp_init are:
-----------------------------------------
// parameters:
// tcp_hostname:
//      host running lnpd to connect - ascii or dotted quad
//      0 means: default to localhost
// tcp_port:
//  portnumber to connect to
//  0 means: default to 7776
// lnp_address:
//  LNP hostaddress to use
//  0 means: default to 0x80
// lnp_mask:
//  LNP hostmask to use
//  0 means: default to 0xF0
// flags:
//      bitwise or of:
//  LNP_DISCARD_WHILE_TX :
//              discard all packets received while waiting for tx result
//
// returns:
//      INIT_OK                 ok, connected to lnp-daemon
//      INIT_BAD_PARAM  bad parameters
//      INIT_ERROR      network error, errno is set
-----------------------------------


oki, guess that was it :)

kenneth



nanobapt
----- Original Message -----
From: kenneth johansen <kennethj@stud.cs.uit.no>
To: nanobapt <nanobapt@nordnet.fr>; <lugnet.robotics.rcx.legos@lugnet.com>
Sent: Monday, August 26, 2002 3:27 AM
Subject: Re: lnp addressing messages

I have some problem to understand the lnp addressing message. How to set
addresse of computer. How to send a message etc ...

hmmmm..okay.......ill give it a shot.
the line below:
result = lnp_addressing_write(data,len ,DEST_ADDR,MY_PORT_1);

will send a message pointed to by data, consisting of len bytes of data to
the DEST_ADDR destination using my MY_PORT_1
port. in your case below you are sending a message to port 2 on host 0. • host
0 is the default address for the PC.
DEST_ADDR is 1 byte consisting of DEST_HOST and DEST_PORT, each 4 bits. • dont
know if you are aware of this, but you must
also start a lnp daemon on the PC before any messages can be received. • Once
the daemon is up and running and you have created a program
on the PC that has a handler that listens on port 2 it should be able to
receive messages.

hope this helps, if you need a better walkthrough let me know and ill c • what
i can do. mind you, i only know how to do this in linux  :)


kenneth
kennethj@stud.cs.uit.no

I have an example (lnpd example but i don't understand this :

#define DEST_ADDR ( DEST_HOST << 4 | DEST_PORT )
result = lnp_addressing_write(data,len ,DEST_ADDR,MY_PORT_1);

here is the complete program :

//
// kleines Testprogram für linux lnp
//

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>

#include "liblnp.h"

#define MY_PORT_1  7
#define MY_PORT_2  8

#define DEST_HOST 0
#define DEST_PORT 2
#define DEST_ADDR ( DEST_HOST << 4 | DEST_PORT )
#define LEN 253

void addr_handler_1(const unsigned char* data,unsigned char length, • unsigned
char src)
{
   char pbuf[100];

   sprintf(pbuf,">> Source:%2X Length:%u PacketNo:%u
<<\n",(unsigned)src,(unsigned)length,(unsigned)data[0]);

   write(STDERR_FILENO,pbuf,strlen(pbuf));
}

void addr_handler_2(const unsigned char* data,unsigned char length, • unsigned
char src)
{
   char pbuf[100];

   sprintf(pbuf,">> Source:%2X Length:%u PacketNo:%u
<<\n",(unsigned)src,(unsigned)length,(unsigned)data[0]);

   write(STDERR_FILENO,pbuf,strlen(pbuf));
}

void int_handler(const unsigned char* data,unsigned char length)
{
   char pbuf[100];

   sprintf(pbuf,">> Integrity Length:%u PacketNo:%u
<<\n",(unsigned)length,(unsigned)data[0]);

   write(STDERR_FILENO,pbuf,strlen(pbuf));
}

int main(int argc, char *argv[])
{
   char data[253];
   int i;
   lnp_tx_result result;
   unsigned char len;
   int count = 0;

   for (i=0;i<sizeof(data);i++) data[i] = i;

   if ( lnp_init(0,0,0,0,0) )
   {
    perror("lnp_init");
    exit(1);
   }

   else fprintf(stderr,"init OK\n");

   lnp_addressing_set_handler (MY_PORT_1, addr_handler_1);
   lnp_addressing_set_handler (MY_PORT_2, addr_handler_2);
   lnp_integrity_set_handler (int_handler);

   while (1)
   {
    file://sleep(1000);
    file://continue;
    len = LEN; file://random() % 252 + 1;
result = lnp_addressing_write(data,len ,DEST_ADDR,MY_PORT_1);
switch (result)
{
        case TX_SUCCESS:
         printf("Tansmitted %d : %d\n",len,count++);
      break;
     case TX_FAILURE:
      printf("Collision\n");
         break;
        default:
         perror("Transmit error");
         exit(1);
       }
}

   return 0;
}


thanks


nanobapt




Message is in Reply To:
  Re: lnp addressing messages
 
(...) hmmmm..okay.......ill give it a shot. the line below: result = lnp_addressing_write(data,len ,DEST_ADDR,MY_PORT_1); will send a message pointed to by data, consisting of len bytes of data to the DEST_ADDR destination using my MY_PORT_1 port. (...) (22 years ago, 26-Aug-02, to lugnet.robotics.rcx.legos)

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