Re: [lwip-users] Suggestion2

[Oscar F]

Mathias, maybe this code example can be useful.

portTASK_FUNCTION( vBasicTFTPServer, pvParameters ){
       int lSocket;
       struct sockaddr_in sLocalAddr, sDestAddr;
       char reply[]="testing";
       char buffer[1024];
       int nbytes;
       int i;

       lSocket = lwip_socket(AF_INET, SOCK_DGRAM, 0);
       
       memset((char *)&sLocalAddr, 0, sizeof(sLocalAddr));
       memset((char *)&sDestAddr, 0, sizeof(sDestAddr));

       /*Destination*/
       sDestAddr.sin_family = AF_INET;
       sDestAddr.sin_len = sizeof(sDestAddr);
       sDestAddr.sin_addr.s_addr = htonl(INADDR_BROADCAST);
       sDestAddr.sin_port = 1234;
       
       /*Source*/
       sLocalAddr.sin_family = AF_INET;
       sLocalAddr.sin_len = sizeof(sLocalAddr);
       sLocalAddr.sin_addr.s_addr = htonl(INADDR_ANY);
       sLocalAddr.sin_port = 1235;

       lwip_bind(lSocket, (struct sockaddr *)&sLocalAddr, sizeof(sLocalAddr));

            while (1) 
            {
 
                         nbytes=lwip_recv(lSocket, buffer, 
            sizeof(buffer),8);
 
                         if 
            (nbytes>0){
                    
            lwip_sendto(lSocket, buffer, nbytes, 0, (struct sockaddr *)&sDestAddr, sizeof(sDestAddr));
 
                         }

              
            lwip_sendto(lSocket, reply, sizeof(reply), 0, (struct sockaddr *)&sDestAddr, sizeof(sDestAddr));
              
            vTaskDelay( 200 
            );  //some delay!
       
            }
       
            lwip_close(lSocket);
}

In my case this could be:

//Open he socket permanent and bind

while(1)
 {
   
 -  if there is some command received with select API i'll process.  "function to process the command receive"

 - if i've to transmit any command i'll send. For example with a semaphore to wait the interrupt or tick function say me every second pass to send the next command.   "function to process the command to send"

- if i´ve to retransmit any command i´ll send too.  "function to process the command to send again"

-and finally  
            vTaskDelay( 10mseg 
            );  //avoid always enter in this loop 

}

//unbind socket and close here and when i had recived the command END.

Is a good solution?

thanks!!!

Oscar

On Fri, Jul 31, 2009 at 8:15 AM, Oscar F <address@hidden> wrote:

Thanks Mike!, in few days i hope to know what protocol prefer to use the customer, i think that will be SDP, because he said me that i've to send ACK or NACK for every command.

Regards
Oscar

On Fri, Jul 31, 2009 at 8:07 AM, Mike Kleshov <address@hidden> wrote:

2009/7/31 Oscar F <address@hidden>:

> thank you, and another question, ¿with this API, can i receive and send the
> command? TCP or UDP? and what is your advice about to have one socket open
> permanent or one socket  for every commmunication?

The answer to the question 'TCP or UDP' will depend on the
requirements of your application. You know them better than anyone on
this list.
An you know, UDP is basically exchange of datagrams. Those are limited
in size and you have to be prepared that occasionally they will not
reach their destination. TCP allows you to stream data (no limit on
data size) and it gives you reliable transport (retransmissions are
handled automatically) but that comes at a cost: TCP code is much more
complex and you have almost no control of the retransmission algorithm
which can be too slow for some applications.

Regards,
- mike

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