While TCP_OVERSIZE works only when tcp_write() is used with
TCP_WRITE_FLAG_COPY, this new code achieves
similar benefits for the use case that the caller manages their own
send buffers and passes successive chunks of those to tcp_write()
without TCP_WRITE_FLAG_COPY.
In particular, if a buffer is passed to
tcp_write() that is adjacent in memory to the previously passed
buffer, it will be combined into the previous ROM pbuf reference
whenever possible, thus extending that ROM pbuf rather than allocating
a new ROM pbuf.
For the aforementioned use case, the advantages of this code are
twofold:
1) fewer ROM pbufs need to be allocated to send the same data, and,
2) the MAC layer gets outgoing TCP packets with shorter pbuf chains.
Original patch by Ambroz Bizjak <ambrop7@gmail.com>
Edited by David van Moolenbroek <david@minix3.org>
Signed-off-by: goldsimon <goldsimon@gmx.de>
This commit returns LwIP to previous behavior where if the next unsent
segment can't be sent due to the current send window, we start the
persist timer. This is done to engage window probing in the case that
the subsequent window update from the receiver is dropped, thus
preventing connection deadlock
This commit refines the previous logic to only target the following case:
1) Next unsent segment doesn't fit within the send window (not
congestion) and there is some room in the window
2) Unacked queue is empty (otherwise data is inflight and the RTO timer
will take care of any dropped window updates)
See commit d8f090a759 (which removed this
behavior) to reference the old logic. The old logic falsely started the
persit timer when the RTO timer was already running.
This comment is incorrect since commit 7d0dab9d7d
"partly fixed bug #25882: TCP hangs on MSS > pcb->snd_wnd
(by not creating segments bigger than half the window)".
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Let lwip use functions/macros prefixed by lwip_ internally to avoid naming clashes with external #includes.
Remove over-complicated #define handling in def.h
Make functions easier to override in cc.h. The following is sufficient now (no more LWIP_PLATFORM_BYTESWAP):
#define lwip_htons(x) <your_htons>
#define lwip_htonl(x) <your_htonl>
It is possible that the byte sent as a zero window probe is accepted
and acknowledged by the receiver side without the window being opened.
In that case, the stream has effectively advanced by one byte, and
since lwIP did not take this into account on the sender side, the
result was a desynchronization between the sender and the receiver.
That situation could occur even on a lwIP loopback device, after
filling up the receiver side's receive buffer, and resulted in an ACK
storm. This patch corrects the problem by advancing the sender's next
sequence number by one as needed when sending a zero window probe.
This was missed in commit aa0e41c389
("task #12178: hardware checksum capabilities can be configured per netif"),
fix it.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
We used a static 4 instead of MEM_ALIGNMENT earlier, however it broke
things for MEM_ALIGNMENT 1 or 2, fixed using a LWIP_MIN(MEM_ALIGNMENT,
4) statement.
ip_addr_t is used for all generic IP addresses for the API, ip(4/6)_addr_t are only used internally or when initializing netifs or when calling version-related functions
