Hello again.
I had a look at the points you mentioned to me:
First of all, I have checked that MSG_DONTWAIT in the flags to the recv
operation, and O_NONBLOCK to the socket options are both set to zero. In
fact, both flag fields are completely zero. So that the socket should be
blocking, am I right?
>Take a look at the lwip_recvfrom() function. Can you check the following
when you call it by adding some extra debugging:
> - that sock->lastdata is NULL.
OK, it is null
> - that buf returned by netconn_recv() is NULL.
It is null too.
>If that is the case, take a look at netconn_recv(). This can return NULL
for all sorts of reasons. Add debugging (e.g. a printf) to each one and
>see which case is failing.
Next, I specify the failing case, which shows the reason for which the
function returns NULL.
struct netbuf *
netconn_recv(struct netconn *conn)
{
...
if (conn == NULL) {
return NULL;
}
if (conn->recvmbox == SYS_MBOX_NULL) {
conn->err = ERR_CONN;
return NULL;
}
if (conn->err != ERR_OK) {
return NULL;
}
if (conn->type == NETCONN_TCP) {
if (conn->pcb.tcp->state == LISTEN) {
conn->err = ERR_CONN;
return NULL;
}
buf = memp_malloc(MEMP_NETBUF);
if (buf == NULL) {
conn->err = ERR_MEM;
return NULL;
}
sys_mbox_fetch(conn->recvmbox, (void **)&p);
if (p != NULL)
{
len = p->tot_len;
conn->recv_avail -= len;
}
else <<<<<<<<<<<<<<<<<<<<<<<<< IT GETS INTO THIS ELSE
len = 0;
printf("\n Entra en el ELSE, Chkp1\n");
/* Register event with callback */
if (conn->callback)
(*conn->callback)(conn, NETCONN_EVT_RCVMINUS, len);
printf("\n Entra en el Callback, Chkp2\n");
/* If we are closed, we indicate that we no longer wish to receive
data by setting conn->recvmbox to SYS_MBOX_NULL. */
if (p == NULL) { <<<<<<<<<<<<<<<<<<<<<<<<< IT GOES INTO THIS IF
(p==NULL)
memp_free(MEMP_NETBUF, buf);
sys_mbox_free(conn->recvmbox);
conn->recvmbox = SYS_MBOX_NULL;
return NULL; <<<<<<<<<<<<<<<<<<<<<<<<< RETURNS NULL
}
....
....
....
return buf;
}
The problem seems to be that it is receiving that null p. I would thank
any advice.
Thank you very much for your help and for using your time for this
purpose.
Best regards,
Borja.
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