Re: [lwip-users] help request; need to get a grip of lwIP

[Bill Auerbach]

Mauro,

If you're using a static IP address, you need to call netif_set_up yourself
once you've set the static IP in the netif.  If you're using DHCP or AutoIP
these both call netif_set_up and so it will happen automatically once an IP
address is established by these methods.

Bill

>-----Original Message-----
>From: address@hidden
>[mailto:address@hidden On
>Behalf Of address@hidden
>Sent: Wednesday, November 16, 2011 4:35 PM
>To: Mailing list for lwIP users
>Subject: Re: [lwip-users] help request; need to get a grip of lwIP
>
>Real sorry.
>I sent the message before it was finished.
>Continuation follows below.
>
>Regards
>Mauro
>
>----- Messaggio originale -----
>> Hi,
>> I'm struggling with my first lwIP port.
>> I need to implement a few services, mostly based on TCP.
>>
>> One of the first things I need to do is to create a socket to allow
>> remote to connect, when this happens I should start sending some
>> logging messages over the socket.
>> If none is connected messages are silently discarded.
>>
>> My real problem is to get to the first stage of the connection.
>>
>> For some tests I used apps/tcpecho_raw as template.
>>
>> My main program calls (no prior lwIP code) the function IP_start(0).
>>
>> ---------------------------------------------------------------
>> struct netif netif;
>>
>> /* static port number; workaround for lwIP slipif deficencies */
>> int slipif_port = -1;
>>
>> static void ip_init(void *param)
>> {
>> IP4_ADDR(&gw, 192, 168, 0, 1);
>> IP4_ADDR(&ipaddr, 192, 168, 0, 2);
>> IP4_ADDR(&netmask, 255, 255, 255, 0);
>>
>> netif_add(&netif, &ipaddr, &netmask, &gw, NULL, slipif_init,
>> tcpip_input);
>> nmea_init();
>> }
>>
>> error_t IP_start(u8_t port)
>> {
>> if (slipif_port != -1)
>> {
>> main_debug_printf("IP_start: already initialized!\r\n");
>> return FAILURE;
>> }
>> slipif_port = port;
>>
>> tcpip_init(ip_init, NULL);
>> return SUCCESS;
>> }
>> ---------------------------------------------------------------
>> nmea_init() is the function that initializes my application
>> ---------------------------------------------------------------
>---------------------------------------------------------------
>void nmea_init(void)
>{
>   LWIP_DEBUGF(N_DEBUG, ("nmea_init: start\r\n"));
>   nmea_pcb = tcp_new();
>   if (nmea_pcb != NULL)
>   {
>      err_t err;
>
>      err = tcp_bind(nmea_pcb, IP_ADDR_ANY, 1000);
>      if (err == ERR_OK)
>      {
>         LWIP_DEBUGF(N_DEBUG, ("nmea_init: bound\r\n"));
>
>         nmea_pcb = tcp_listen(nmea_pcb);
>         tcp_accept(nmea_pcb, nmea_accept);
>         LWIP_DEBUGF(N_DEBUG, ("nmea_init: waiting for
>connection\r\n"));
>      }
>      else
>      {
>         LWIP_DEBUGF(N_DEBUG, ("nmea_init: unable to bind\r\n"));
>      }
>   }
>   else
>   {
>      LWIP_DEBUGF(N_DEBUG, ("nmea_init: unable to allocate pcb\r\n"));
>   }
>}
>---------------------------------------------------------------
>The function nmea_accept() is never called.
>I traced the error down to lwip/core/ipv4/ip.c where the test:
>---------------------------------------------------------------
>      /* interface is up and configured? */
>      if ((netif_is_up(netif)) && (!ip_addr_isany(&(netif->ip_addr)))) {
>        /* unicast to this interface address? */
>        if (ip_addr_cmp(&current_iphdr_dest, &(netif->ip_addr)) ||
>            /* or broadcast on this interface network address? */
>            ip_addr_isbroadcast(&current_iphdr_dest, netif)) {
>          LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface
>%c%c\n",
>              netif->name[0], netif->name[1]));
>          /* break out of for loop */
>          break;
>        }
>---------------------------------------------------------------
>fails because netif_is_up(netif) returns FALSE.
>
>Struct netif appears to contain the right values, but I'm obviously
>missing some needed initialization.
>
>Can someone point me to some complete initialization fitting my cases?
>I will try debugging through the code and I believe I can find out which
>function does the required initialization, but it's far from being an
>efficient process.
>
>I really need to get a grip on the various programming interfaces lwIP
>has, possibly mixing them in a sensible way.
>
>I will need to implement several semi-unrelated services all insisting
>on the same SLIP connection; some of them are best suited for the RAW
>interface while some other would prefer a connection; is it possible to
>mix (on different applications, of course)?
>
>TiA
>Mauro
>
>
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