On Thu, Jan 19, 2017 at 03:46:49AM -0800, Simon Ratner wrote: > A related question: how does this map to large ATT_MTU and fragmented > packets at the L2CAP level (assuming no data length extension)? Does each > fragment get its own mbuf, which are then chained together, or does the > entire packet get reassembled into a single mbuf if there is room?
If the host needs to send a large packet, it packs the payload into an mbuf chain. By "packs," I mean each buffer holds as much data as possible with no regard to the maximum L2CAP fragment size. When the host sends an L2CAP fragment, it splits the fragment payload off from the front of the mbuf chain, constructs an ACL data packet, and sends it to the controller. If a buffer at the front of mbuf can be freed, now that data has been removed, the host frees it. If you are interested, the function which handles fragmentation and freeing is mem_split_frag() (util/mem/src/mem.c). Chris
