Re: [lwip-users] netconn: freeing netbufs after netconn_recv

[Simon Goldschmidt]

Am 31.10.2007 um 21:23 schrieb Ivan Delamer:

> ...
> Now, I have two questions/concerns:
>
> 1) do I have to manually free/delete the netbuf? I read the source  
> code for netconn_recv and I see a buf = memp_malloc(MEMP_NETBUF)   
> but no "free" in the examples.

Yes, look at sockets.c, lwip_recv() implementation for an example.

> 2) for how long is the data in the netbuf valid? netconn_recv sends  
> a API_MSG_RECV so does this mean that the data may be overwritten?  
> or does it stay valid until I free the netbuf (and underlying pbufs)?

Data stays valid until you free the netbuf. API_MSG_RECV updates the  
TCP window so that the remote side can send more data. If you don't  
free the netbuf, you will eventually run out of pbufs/netbufs.

> The way I see it, I should call netbuf_delete() after I'm done  
> processing the data, but I couldn't find any example of this.

As mentioned above, look at sockets.c, lwip_recv() implementation.

> Thanks in advance again,
> Ivan
>
> PS: anybody have an HTTPD server sample? something more complex  
> than the example, I will use a thread pool for processing requests  
> and hopefully implement keep-alive.

The only netconn HTTPD example I know of is in the CVS contrib  
module, apps directory.


Simon