On Tue, 2007-05-22 at 15:47 +0200, Goldschmidt Simon wrote: > > > That would make ICMP dependent of the link layer! > > > > No more so than TCP, UDP, etc. It would (if there wasn't > > enough space in the pbuf it already had) simply allocate a > > pbuf using the PBUF_IP pbuf_layer flag, and so it would have > > enough space reserved for the IP and link headers. > > But how does the ICMP code know how much space to reserve fo the > link layer?
Look at the start of pbuf_alloc(). It increases the required length depending on what pbuf_layer is. It uses the port-defined constants PBUF_TRANSPORT_HLEN, PBUF_IP_HLEN and PBUF_LINK_HLEN to know how much it needs to reserve for the headers of each layer. Kieran _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
