Re: [lwip-users] sendind tcp data and created pbuf's

[Kieran Mansley]

On Wed, 2009-10-14 at 16:28 +0200, Martin Velek wrote:
> Hello,
> 
> I am using an emac driver which can handle only word sized(divisible
> by 4) pbuf's except the last one in a pbuf chain.
> Is possible that netconn_write can cause a multiple pbuf's without
> divisible len?
> 
> E.g.
> netconn_write (..., datalen = 111, ...)
> netconn_write (..., datalen = 111, ...)
> netconn_write (..., datalen = 111, ...)
> 
> will generate a packet in pbuf chain
> 
> pbuf (0) - len = eth + ip + tcp headers
> pbuf (1) - len = 111
> pbuf (2) - len = 111
> ...

Yes, it could do that.  It could also chain the data pbufs onto an
existing segment in the unsent list, but the individual pbufs will
usually be of the length specfied by the netconn_write (unless the write
is larger than a pbuf, in which case it will be split of course).

Kieran