Does the code handle case where a sent but not ACKed STREAM has to be repathed to a lower MTU path?

[pjakma]

Hi,

I'm trying to figure out if the code handles the case where a STREAM frame that has been buffered (but not sent) has to be repathed onto a new path, where the new path has an MTU that can not accommodate the STREAM frame as it is.

I'd expect either the STREAM frame itself has to be split up into multiple frames, or the data queued in the frame has to be pushed back up to the stream code for it to handle it. But I can't find this code. I can see how packet-resize splits out frames of a packet, but nothing on how a over-size STREAM might be split.

How should this work?

Thanks, Paul

[pjakma]

From a comment on slack it seems split_buffered/lost should be doing this. But (AFAICT) it can only split out whole frames from packets - it can not further split a frame. So it sounds like lsquic_stream.c or somewhere needs a facility to split a STREAM frame, so that split_* in lsquic_sendctl.c can use that, as needed.