Re: [lwip-users] What is pbuf's payload?

[Chen]

Sorry, but I am answering my own question again...

1) tcpip_input posts the message TCPIP_MSG_INPUT with pbuf, along with
its payload
2) tcpip_thread picks up the message and calls ethernet_input because
NETIF_FLAG_ETHARP was set in low_level_init during
ethernetif_init
3) ethernet_input looks at pbuf's payload, which
starts with Ethernet header, and based on the type, it calls
ip_input or others

I'd like to catch an UDP packet without parcing it
all the way. If anyone has any pointer, please suggest, thanks


> Date: Thu, 02 Aug 2012 16:53:57
> -0400
> From: Chen <address@hidden>
> To: address@hidden
> Subject: [lwip-users] What is pbuf's payload?
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset="us-ascii";
> Format="flowed"
>
> Hi there,
>
> I am trying to understand pbuf's payload referenced in 
> tcpip_input(struct pbuf *p, struct netif *inp)
>
> pbuf's payload is defined as void *, what are the possible structures
> it can be under tcpip_input()?
>
> since tcpip_input deals with udp and tcp only, is it just the actual
> data from udp and tcp packets?
>
> thanks for any pointer
>
> Chen