Re: [lwip-users] Question about udp_recv()

[Jin Won Seo]

Thanks Marty,

I should have mentioned what version of lwip lib I use.

StellarisWare 10363 which is latest version still uses lwip1.3.2, so I don't see the first line "mpcb->recv(....)", but I see the second line inside udp_input() in udp.c.

I need to look over how/when arguments are filled up. pcb->recv() is called inside udp_input(), so I guess whenever incoming UDP datagram takes place, the arguments are filled up in lwip1.3.2.

Thank you for giving me a tip.

Jin

On Fri, Jul 19, 2013 at 4:05 AM, Pomeroy, Marty <address@hidden> wrote:

>> My question I don't see any arguments passed to  callback functions : udp_recv() and TFTPRecv().
>> How are the arguments going to be filled up and by whom??

 

 

Jin

 

After review of the udp.c code, it looks to me that udp_recv is a setup function (not a callback...), and you use it to tell lwIP what function to call with UDP traffic.  Once set up, your TFTPRecv function is called in the udp.c module by one of these two lines (in lwIP 1.4.0):

 

   mpcb->recv(mpcb->recv_arg, mpcb, q, ip_current_src_addr(), src);

...
   pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr(), src);

 

Hope that helps!

 

Marty

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