Re: [PATCH] net: lwip: handle chained pbufs in transmit path

[Weijie Gao <weijie.gao@mediatek.com>]

On Mon, 2026-07-27 at 16:02 +0800, Weijie Gao wrote:
> LwIP may pass a packet to the netif linkoutput callback as a chain
> of pbufs. In this case, p->len only describes the length of the
> first pbuf, while p->tot_len describes the length of the whole
> packet.
> 
> The current transmit path only sends the first pbuf. This can
> truncate packets whose headers have already been generated for the
> full packet length, resulting in malformed frames on the wire.
> For example, the IP header may record a larger total length than the
> actual Ethernet frame length.
> 
> Assemble chained pbufs into one aligned contiguous buffer before
> passing the packet to the Ethernet driver.
> 
> Fixes: 98ad145db61a (net: lwip: add DHCP support and dhcp commmand)
> Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> ---
>  net/lwip/net-lwip.c | 45 ++++++++++++++++++++++++++++++++-----------
> --
>  1 file changed, 32 insertions(+), 13 deletions(-)
> 

Sorry, I sent this patch by mistake. Please ignore it.