This reverts commit 1570dd8ad1c6afd2438dcb8b18d9eed794f78baa.
Buffering pcb->local_port is needed because TCP_PCB_REMOVE_ACTIVE()
sets it to 0 via tcp_pcb_remove() (comment: "reset the local port
to prevent the pcb from being 'bound'").
Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>
This introduces the concept of ext (external/extended) arguments per
tcp_pcb (also for listening pcbs) to store more data than just one
"void *arg" per pcb. The "arg" is for use to applications, whereas
the ext_args may be used by frameworks and leave "arg" untouched.
In addition to a void pointer, callbacks are added to help frameworks
migrate arguments from listen pcb to connection pcb and to free args
when the pcb is freed.
Signed-off-by: goldsimon <goldsimon@gmx.de>
This should make it easier to add debugging messages or other hooks
to the point where tcp pcbs are deallocated.
Signed-off-by: goldsimon <goldsimon@gmx.de>
We preserved the TIME_WAIT handling before, but it seems this is not correct: we want to issue
a RST later again if someone wants to talk to this port. With TIME_WAIT, this might not always
the case.
This avoid having a second description for the same stuff that is "bit-rotting" because noone remembers to update this file.
Also remove outdated and misleading zero-copy TX information.
This re-works the persist timer to have the following behavior:
1) Only start persist timer when a buffered segment doesn't fit within
the current window and there is no in-fligh data. Previously, the
persist timer was always started when the window went to zero even
if there was no buffered data (since timer was managed in receive
pathway rather than transmit pathway)
2) Upon first fire of persist timer, fill the remaining window if
non-zero by splitting the unsent segment. If split segment is sent,
persist timer is stopped, RTO timer is now ensuring reliable window
updates
3) If window is already zero when persist timer fires, send 1 byte probe
4) Persist timer and zero window probe should only be active when the
following are true:
* no in-flight data (pcb->unacked == NULL)
* when there is buffered data (pcb->unsent != NULL)
* when pcb->unsent->len > pcb->snd_wnd
- add a better-documented static function tcp_output_segment_busy
- try to reduce the number of checks
- tcp_rexmit_rto: iterate pcb->unacked only once
- no need to check for ref==1 in tcp_rexmit_fast when tcp_rexmit does
- call tcp_rexmit_fast if dupacks >= 3 (not == 3) and use TF_INFR flag to guard the fast-rexmit case (that way, it's triggered again on the next dupack)
Adds partial support for selective acknowledgements (RFC 2018).
This change makes lwIP negotiate SACK support, and include SACK
data in outgoing empty ACK packets. It does not include it
in outgoing packets with data payload.
It also does not add support for handling incoming SACKs.
Signed-off-by: goldsimon <goldsimon@gmx.de>
This commit adds a timeout to the zero-window probing (persist timer)
mechanism. LwIP has not historically had a timeout for the persist
timer, leading to unbounded blocking if connection drops during the
zero-window condition
This commit also adds two units test, one to check the RTO timeout
and a second to check the zero-window probe timeout
