[lwip-users] Pbuf chain

[Mike He]

If my understanding is correct, the pbuf that is passed to our recv 
callback is only the first in a chain, where we must traverse the chain 
to obtain the full packet?

I am confused by this line in the documentation:
"The last pbuf of a packet has a ->tot_len field that equals the ->len 
field. It can be found by traversing the list. If the last pbuf of a 
packet has a ->next field other than NULL, more packets are on the queue.

Therefore, looping through a pbuf of a single packet, has an loop end 
condition (tot_len == p->len), NOT (next == NULL)."

Why would there be two conditions? Is ever one true when the other 
isn't? How do the lengths add up if the first condition is true but the 
second isn't?

Does anyone have example code for how to obtain the full packet?


Thanks,
Mike