Re: [lwip-users] tcp_write() problem from outside callbacks functions

[Yann Suisini]

the facts say that you're probably right . (the tcp state in the calback just
before tcp_write is ESTABLISHED , and in the main loop is LISTEN) . But I
really don't know where is the trouble . All is passed by reference with the
same tcp_pcb (tcpweb).

I put the other interesting part of the code here : 
(in the receive callback , just in order to test i send data on a '+'
trigger)

Here the connection initialization part: 
        
        tcpweb = tcp_new();
        if (tcpweb == NULL) debug_printf("Creation error\r\n");
        if (tcp_bind(tcpweb, IP_ADDR_ANY, 80) != ERR_OK) debug_printf("Bind
Error\r\n");
        tcpweb_listen = tcp_listen(tcpweb);
        if (tcpweb_listen == NULL)
        {
                tcp_abort(tcpweb);
                tcpweb = NULL;
        }       
        else
        {
                tcpweb = tcpweb_listen;
                tcp_accept(tcpweb, http_accept_callback);
        }

and the callback functions :

err_t http_recv_callback(void *arg, struct tcp_pcb *tpcb, struct pbuf *p,
err_t err)
{
        char* rq;

        if (p != NULL)
        {
                rq = p->payload;

                if (rq[0] == '+')
                {
                        u32_t  bytestosend;
                        u32_t* newarg;

                        bytestosend = sizeof(webpage);

                        newarg = (u32_t*) mem_malloc(sizeof(u32_t));
                        *newarg = bytestosend;  

                        debug_printf("tcp state:%d\r\n",tpcb->state);
                        if (tcp_write(tpcb, webpage, sizeof(webpage), 0) != 
ERR_OK)
                        {
                                mem_free(newarg);
                                tcp_close(tpcb);                
                        }
                        else
                        {
                                tcp_arg(tpcb, newarg);
                                mem_free(newarg);
                        }


                }

                tcp_recved(tpcb, p->len);
                pbuf_free(p);           
        }

err_t http_poll_callback(void *arg, struct tcp_pcb *tpcb)
{
        if (arg != NULL)
        {
                u32_t bytestosend = *((u32_t*) arg);

                if (bytestosend == 0)
                {
                        mem_free(arg);
                        tcp_arg(tpcb, NULL);
                        tcp_close(tpcb);
                        debug_printf("Closing connection");
                }
        }

        return ERR_OK;
}

err_t http_send_callback(void *arg, struct tcp_pcb *tpcb, u16_t len)
{
        u32_t bytestosend;

        if (arg != NULL)
        {
                bytestosend = *((u32_t*) arg);

                if ((bytestosend - len) >= 0)
                        bytestosend -= len;
                else
                        bytestosend = 0;

                *((u32_t*) arg) = bytestosend;
        }
        return ERR_OK;
}

err_t http_accept_callback(void *arg, struct tcp_pcb *newpcb, err_t err)
{
        tcp_arg(newpcb, NULL);
        tcp_recv(newpcb, http_recv_callback);
        tcp_sent(newpcb, http_send_callback);
        tcp_poll(newpcb, http_poll_callback, 1);

        return ERR_OK;
}
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