Re: [lwip-users] Using tcp_write() outside tcp_recv callback

[address@hidden]

Am 08.04.2020 um 00:08 schrieb Jamie:
> Just following up on this, as I haven't had time to continue working on it
> until today. To provide more context, I'll provide some code snippets and
> commentary around the code. I don't imagine I'm too far off getting it
> working, as I've not changed too much of the echo example source.

I'm not sure what you're getting at. This looks a lot different to the
excho example to me...

Regards,
Simon

>
> *My init function:*
> init_PCB = tcp_new();
>
> if (init_PCB != NULL) {
>
>     err_t err;
>
>     err = tcp_bind(init_PCB, IP_ADDR_ANY, 9999);
>
>     if (err == ERR_OK) {
>
>         init_PCB = tcp_listen(init_PCB);
>
>         tcp_accept(init_PCB, tcp_accept_callback);
>
>     } else {
>
>         memp_free(MEMP_TCP_PCB, init_PCB);
>
>     }
>
> }
>
> My accept callback: (void *arg, struct tcp_pcb *tempPCB, err_t err)
> err_t ret_err;
>
> struct tcp_package *tcpPackage;
>
> global_PCB = tempPCB;
>
> tcp_nagle_disable(global_PCB);
>
> LWIP_UNUSED_ARG(arg);
> LWIP_UNUSED_ARG(err);
>
> tcp_setprio(global_PCB, TCP_PRIO_MIN);
>
> tcpPackage = (struct tcp_package *)mem_malloc(sizeof(struct tcp_package));
>
> if (tcpPackage != NULL) {
>
>     tcpPackage->state = TCP_STATE_ACCEPTED;
>     tcpPackage->pcb = global_PCB;
>     tcpPackage->retries = 0;
>     tcpPackage->p = NULL;
>
>     tcp_arg(global_PCB, tcpPackage);
>     tcp_recv(global_PCB, tcp_recv_callback);
>     tcp_err(global_PCB, tcp_err_callback);
>
>     ret_err = ERR_OK;
>
> } else {
>
>     ret_err = ERR_MEM;
>
> }
>
> I'll leave the tcp_recv_callback function for the time being, as I'm
> focusing on TX at the moment, and the RX side seems to work without issue.
>
> In terms of sending data, I have an interrupt callback function, where some
> data is processed (not shown below for simplicity). I package an unsigned
> char buffer with data from two other buffers, separated by a ';' character.
> Code shown below:
>
> unsigned char bufferMain[32];
> char buffer1[10];
> char buffer2[10];
>
> //Some processing of data; buffer1 and buffer2 are populated
>
> snprintf(bufferMain, sizeof(bufferMain), "%s%s%s", buffer1, ";", buffer2);
>
> //Register the sent callback
> tcp_sent(global_PCB, tcp_sent_callback);
>
> err_t err;
> err = tcp_write(global_PCB, bufferMain, sizeof(bufferMain), 1);
> err = tcp_output(global_PCB);
>
> As mentioned in my original post, I have trace points throughout the code,
> including the 'err' return values for tcp_write() and tcp_output() above.
> When I run the code, I get 2-3 ERR_OK values from tcp_write, and data is
> received by the remote CPU, but err then becomes -1, and (through another
> trace point) I determine the error to be:
>
> "tcp_write : could not allocate memory for pbuf copy size 32"
>
> Here is my tcp_sent_callback: (void *arg, struct tcp_pcb *tpcb, u16_t len)
> struct tcp_package *tcpPackage;
>
> struct pbuf *ptr;
>
> LWIP_UNUSED_ARGE(len);
>
> tcpPackage = (struct tcp_package *)arg;
>
> ptr = tcpPackage->p;
>
> tcpPackage->retries = 0;
>
> if (tcpPackage->p != NULL) {
>
>     tcp_sent(tpcb, tcp_sent_callback);
>
>     //I don't use the tcp_send function, so don't currently use this
> functionality
>     //In theory I shouldn't need this functionality, as each tcp_write() is
> for a single pbuf
>     //tcp_send)tpcb, tcpPackage);
>
> } else {
>
>     if (tcpPackage->state == TCP_STATE_CLOSING) {
>
>         tcpClose(tpcb, tcpPackage);
>
>     }
>
>     uint8_t freePBUF;
>
>     do {
>
>         freePBUF = pbuf_free(ptr);
>
>     } while (freePBUF == 0);
>
> }
>
> return ERR_OK;
>
> Is there anything obvious that I'm missing or have done incorrectly in the
> above? In my mind, I've registered the sent callback, so after tcp_write()
> and tcp_output(), the do-while pbuf_free() should deallocate memory, but it
> looks like that may not be the case, given the "could not allocate memory
> for pbuf copy size" error.
>
> Any guidance would be greatly appreciated!
>
>
>
> --
> Sent from: http://lwip.100.n7.nabble.com/lwip-users-f3.html
>
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