Re: [lwip-users] Raw lwIP server write issue

[Valery Ushakov]

Amit Ashara  wrote:

> Do you mean that instead of using pcb I should have another tcp_pcb e,g,
> newpcb that is assigned from the pcb in the call back.
> 
> struct tcp_pcb *newpcb;
> 
> static err_t echo_accept(void *arg, struct tcp_pcb *pcb, err_t err)
> 
> {
>   LWIP_UNUSED_ARG(arg);
>   LWIP_UNUSED_ARG(err);
> 
>   newpcb = pcb;

Exactly.


> On Thu, Nov 5, 2015 at 11:28 AM, Valery Ushakov  wrote:
> 
>> Amit Ashara  wrote:
>>
>> > When a connection is established between the server and the client,
>> > I can use the tcp_write on the client side to send data in my
>> > application code.  However the same on the server side is not
>> > possible.  The pcb that has been used for the server only contains
>> > the server's address and server's port but not the client's address
>> > and client's port.  In the receive call back on the server side, I
>> > can send the data to the client but not outside of the call back.
>>
>> You are using wrong pcb.  On the server you start with a listening
>> pcb.  When your accept callback is called, it's passed a *new* pcb,
>> that represents the established connection.  You should use that pcb
>> for tcp_write.  Writing from receive callback works because in the
>> receive callback the pcb argument is that connection pcb, not the
>> original listening pcb.
>>
>> -uwe

-uwe


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Re: [lwip-users] Raw lwIP server write issue

[Amit Ashara]

Thanks Uwe.

On Fri, Nov 6, 2015 at 5:17 PM, Valery Ushakov  wrote:

> Amit Ashara  wrote:
>
> > Do you mean that instead of using pcb I should have another tcp_pcb e,g,
> > newpcb that is assigned from the pcb in the call back.
> >
> > struct tcp_pcb *newpcb;
> >
> > static err_t echo_accept(void *arg, struct tcp_pcb *pcb, err_t err)
> >
> > {
> >   LWIP_UNUSED_ARG(arg);
> >   LWIP_UNUSED_ARG(err);
> >
> >   newpcb = pcb;
>
> Exactly.
>
>
> > On Thu, Nov 5, 2015 at 11:28 AM, Valery Ushakov 
> wrote:
> >
> >> Amit Ashara  wrote:
> >>
> >> > When a connection is established between the server and the client,
> >> > I can use the tcp_write on the client side to send data in my
> >> > application code.  However the same on the server side is not
> >> > possible.  The pcb that has been used for the server only contains
> >> > the server's address and server's port but not the client's address
> >> > and client's port.  In the receive call back on the server side, I
> >> > can send the data to the client but not outside of the call back.
> >>
> >> You are using wrong pcb.  On the server you start with a listening
> >> pcb.  When your accept callback is called, it's passed a *new* pcb,
> >> that represents the established connection.  You should use that pcb
> >> for tcp_write.  Writing from receive callback works because in the
> >> receive callback the pcb argument is that connection pcb, not the
> >> original listening pcb.
> >>
> >> -uwe
>
> -uwe
>
>
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Re: [lwip-users] Raw lwIP server write issue

[Valery Ushakov]

Amit Ashara  wrote:

> When a connection is established between the server and the client,
> I can use the tcp_write on the client side to send data in my
> application code.  However the same on the server side is not
> possible.  The pcb that has been used for the server only contains
> the server's address and server's port but not the client's address
> and client's port.  In the receive call back on the server side, I
> can send the data to the client but not outside of the call back.

You are using wrong pcb.  On the server you start with a listening
pcb.  When your accept callback is called, it's passed a *new* pcb,
that represents the established connection.  You should use that pcb
for tcp_write.  Writing from receive callback works because in the
receive callback the pcb argument is that connection pcb, not the
original listening pcb.

-uwe


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Re: [lwip-users] Raw lwIP server write issue

[Amit Ashara]

Hello Uwe,

I have the call back for accept set as follows.

In the main application, I call echo_accept.

server_tpcb = tcp_new();
ui32Err = tcp_bind(server_tpcb, (ip_addr_t
*)_ui32IPAddress, NODE_TCP_SERVER_PORT);
UARTprintf("\n%d",ui32Err);
server_tpcb = tcp_listen(server_tpcb);
tcp_accept(server_tpcb, echo_accept);

which is as follows.

static err_t echo_accept(void *arg, struct tcp_pcb *pcb, err_t err)

{
  LWIP_UNUSED_ARG(arg);
  LWIP_UNUSED_ARG(err);

  tcp_setprio(pcb, TCP_PRIO_MIN);
  tcp_arg(pcb, NULL);
  tcp_recv(pcb, echo_recv);
  tcp_err(pcb, echo_err);
  tcp_poll(pcb, NULL, 0);
  return ERR_OK;
}

Do you mean that instead of using pcb I should have another tcp_pcb e,g,
newpcb that is assigned from the pcb in the call back.

struct tcp_pcb *newpcb;

static err_t echo_accept(void *arg, struct tcp_pcb *pcb, err_t err)

{
  LWIP_UNUSED_ARG(arg);
  LWIP_UNUSED_ARG(err);

  newpcb = pcb;

  tcp_setprio(pcb, TCP_PRIO_MIN);
  tcp_arg(pcb, NULL);
  tcp_recv(pcb, echo_recv);
  tcp_err(pcb, echo_err);
  tcp_poll(pcb, NULL, 0);
  return ERR_OK;
}

Regards
Amit

On Thu, Nov 5, 2015 at 11:28 AM, Valery Ushakov  wrote:

> Amit Ashara  wrote:
>
> > When a connection is established between the server and the client,
> > I can use the tcp_write on the client side to send data in my
> > application code.  However the same on the server side is not
> > possible.  The pcb that has been used for the server only contains
> > the server's address and server's port but not the client's address
> > and client's port.  In the receive call back on the server side, I
> > can send the data to the client but not outside of the call back.
>
> You are using wrong pcb.  On the server you start with a listening
> pcb.  When your accept callback is called, it's passed a *new* pcb,
> that represents the established connection.  You should use that pcb
> for tcp_write.  Writing from receive callback works because in the
> receive callback the pcb argument is that connection pcb, not the
> original listening pcb.
>
> -uwe
>
>
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