Re: [lwip-users] lwip on freertos

[Jesper Vestergaard]

address@hidden wrote:
> > On Tue, 2009-06-09 at 17:12 +0200, Jesper Vestergaard wrote:
> >     
> > > I have found the problem. ip_output_if generates a header for the packet
> > > but there's not enough room for it and  pbuf_header(p, IP_HLEN)) fails.
> > > To be more precise it is the if ((u8_t *)p->payload < (u8_t *)p +
> > > SIZEOF_STRUCT_PBUF) check in pbuf_header which fails.
> > >
> > > What can i do to fix this problem?
> > >
> > >       
> > That is a very strange problem, the pbuf should have been allocated with
> > enough space to contain the IP header.
> >
> > Unfortunately, this code has changed a lot recently (since 1.3.0) so
> > it's hard to diagnose using the current CVS head, or even establish if
> > the problem still exists.
> >
> > To investigate, look for where the pbuf is allocated (should be in
> > tcp_enqueue() I think), and see what value is given for the first
> > argument "pbuf_layer layer".  It is this that should control the
> > additional space allocated for lower layer headers.
> >
> > Kieran
> >
> >
> >
> > _______________________________________________
> > lwip-users mailing list
> > address@hidden
> > http://lists.nongnu.org/mailman/listinfo/lwip-users
> >
> >     
>
> Thanks
>
> I will look into the allocation in tcp_enqueue() and also get the CVS
> version for comparison.
>
>
>
> _______________________________________________
> lwip-users mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/lwip-users
>
>
>   
I finally figured out the probem. The ethernetif driver i am using is 
designed for an earlier version of lwip and it seems that lwip changed 
the argument order in etharp_output() in version 1.3.0 so instead of 
putting the header in the pbuffer, lwip tried to put it in ipaddr. So it 
was a quick fix after i figured it out.


Now i have run into a problem with a mailbox in lwip or a queue in 
FreeRTOS. 

I have a printf in netcom accept just after the creation of the newconn 
pointer and after the sys_arch_mbox_fetch and they prints:
"newconn 0x2af6"
and
"mbox fetch: 0x10013540 conn: 0x2af6 recmbox: 0xf01f0046" 

In accept_function i have a printf just before the data is added to the 
mailbox and looks like this:
"mailbox: 0x10013540 conn 0x10002600 recvmbox: 0x100136b0" 

Why isn't the data properly sent through the mailbox or queue? 

Here's the code from lwip: 

/** 
* Accept a new connection on a TCP listening netconn. 
* 
* @param conn the TCP listen netconn 
* @return the newly accepted netconn or NULL on timeout 
*/ 
struct netconn * 
netconn_accept(struct netconn *conn) 
{ 
struct netconn *newconn; 

printf("newconn %p\n", newconn); 

LWIP_ERROR("netconn_accept: invalid conn", (conn != NULL), return NULL;); 
LWIP_ERROR("netconn_accept: invalid acceptmbox", (conn->acceptmbox != 
SYS_MBOX_NULL), return NULL;); 

#if LWIP_SO_RCVTIMEO 
if (sys_arch_mbox_fetch(conn->acceptmbox, (void *)&newconn, 
conn->recv_timeout) == SYS_ARCH_TIMEOUT) { 
newconn = NULL; 
} else 
#else 

sys_arch_mbox_fetch(conn->acceptmbox, (void *)&newconn, 0); 
printf("mbox fetch: %p\ conn: %p recmbox: %p\n",conn->acceptmbox, 
newconn, newconn->recvmbox); 
#endif /* LWIP_SO_RCVTIMEO*/ 
{ 
/* Register event with callback */ 
API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0); 

#if TCP_LISTEN_BACKLOG 
if (newconn != NULL) { 
/* Let the stack know that we have accepted the connection. */ 
struct api_msg msg; 
msg.function = do_recv; 
msg.msg.conn = conn; 
TCPIP_APIMSG(&msg); 
} 
#endif /* TCP_LISTEN_BACKLOG */ 
} 
return newconn; 
} 


/** 
* Accept callback function for TCP netconns. 
* Allocates a new netconn and posts that to conn->acceptmbox. 
* 
* @see tcp.h (struct tcp_pcb_listen.accept) for parameters and return value 
*/ 
static err_t 
accept_function(void *arg, struct tcp_pcb *newpcb, err_t err) 
{ 
struct netconn *newconn; 
struct netconn *conn; 

#if API_MSG_DEBUG 
#if TCP_DEBUG 
tcp_debug_print_state(newpcb->state); 
#endif /* TCP_DEBUG */ 
#endif /* API_MSG_DEBUG */ 
conn = (struct netconn *)arg; 

LWIP_ERROR("accept_function: invalid conn->acceptmbox", 
conn->acceptmbox != SYS_MBOX_NULL, return ERR_VAL;); 

/* We have to set the callback here even though 
* the new socket is unknown. conn->socket is marked as -1. */ 
newconn = netconn_alloc(conn->type, conn->callback); 
if (newconn == NULL) { 
return ERR_MEM; 
} 
newconn->pcb.tcp = newpcb; 
setup_tcp(newconn); 
newconn->err = err; 
/* Register event with callback */ 
API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0); 

printf("mailbox: %p conn %p recvmbox: %p\n", conn->acceptmbox, newconn, 
newconn->recvmbox); 
if (sys_mbox_trypost(conn->acceptmbox, newconn) != ERR_OK) { 
/* When returning != ERR_OK, the connection is aborted in tcp_process(), 
so do nothing here! */ 
newconn->pcb.tcp = NULL; 
netconn_free(newconn); 
return ERR_MEM; 
} 
return ERR_OK; 
} 


/* 
Blocks the thread until a message arrives in the mailbox, but does 
not block the thread longer than "timeout" milliseconds (similar to 
the sys_arch_sem_wait() function). The "msg" argument is a result 
parameter that is set by the function (i.e., by doing "*msg = 
ptr"). The "msg" parameter maybe NULL to indicate that the message 
should be dropped. 

The return values are the same as for the sys_arch_sem_wait() function: 
Number of milliseconds spent waiting or SYS_ARCH_TIMEOUT if there was a 
timeout. 

Note that a function with a similar name, sys_mbox_fetch(), is 
implemented by lwIP.  
*/ 
u32_t sys_arch_mbox_fetch(sys_mbox_t mbox, void **msg, u32_t timeout) 
{ 
void *dummyptr; 
portTickType StartTime, EndTime, Elapsed; 

StartTime = xTaskGetTickCount(); 

if( msg == NULL ) 
{ 
msg = &dummyptr; 
} 

if( timeout != 0 ) 
{ 
if(pdTRUE == xQueueReceive( mbox, &(*msg), timeout ) ) 
{  

EndTime = xTaskGetTickCount(); 
Elapsed = EndTime - StartTime; 
if( Elapsed == 0 ) 
{ 
Elapsed = 1; 
} 
return ( Elapsed ); 
} 
else // timed out blocking for message 
{ 
*msg = NULL; 
return SYS_ARCH_TIMEOUT; 
} 
} 
else // block forever for a message. 
{ 
while( pdTRUE != xQueueReceive( mbox, &(*msg), portMAX_DELAY ) ) // time 
is arbitrary 
{ 
; 
} 
EndTime = xTaskGetTickCount(); 
Elapsed = EndTime - StartTime; 
if( Elapsed == 0 ) 
{ 
Elapsed = 1; 
} 
return ( Elapsed ); // return time blocked TBD test  
} 
} 

/*-----------------------------------------------------------------------------------*/ 
// Try immediately posting the "msg" to the mailbox. 
err_t 
sys_mbox_trypost(sys_mbox_t mbox, void *data) 
{  
if ( xQueueSend( mbox, &data, ( portTickType ) 1 ) == pdPASS ) 
{ 
return ERR_OK; 
} 
else 
{ 
return ERR_MEM; 
} 
}


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