fix regression of invalid update the rexmit_seq in buffer mode
rexmit_seq should not be used instead of sndseq in fast retransmission,
sndseq of retransmission in the packet does not need to be re-updated
Signed-off-by: chao.an <anchao@xiaomi.com>
Retransmit only one the earliest not acknowledged segment
(according to RFC 6298 (5.4)). The issue is the same as it was
in tcp_send_unbuffered.c and tcp_sendfile.c.
Signed-off-by: chao.an <anchao@xiaomi.com>
tcp_sendfile() reads data directly from a file and does not use NET_TCP_WRITE_BUFFERS data flow
even if CONFIG_NET_TCP_WRITE_BUFFERS option is enabled.
Despite this, tcp_sendfile relied on NET_TCP_WRITE_BUFFERS specific flow control variables that
were idle during sendfile operation. Thus it was a total inconsistency.
E.g. because of the issue, TCP socket used by sendfile() operation never issued
FIN packet on close() command, and the TCP connection hung up.
As a result of the fix, simultaneously enabled CONFIG_NET_TCP_WRITE_BUFFERS and
CONFIG_NET_SENDFILE options can coexist.
* Fixes the case where the window was small but not zero.
* tcp_recvfrom: Remove tcp_ackhandler. Instead, simply schedule TX for
a possible window update and make tcp_appsend decide.
* Replace rcv_wnd (the last advertized window size value) with
rcv_adv. (the window edge sequence number advertized to the peer)
rcv_wnd was complicated to deal with because its base (rcvseq) is
also moving.
* tcp_appsend: Send a window update even if there are no other reasons
to send an ack.
Namely, send an update if it increases the window by
* 2 * mss
* or the half of the max possible window size
Squashed commit of the following:
net/tmp: Rename the unacked field of the tcp connection structure to tx_unacked. Too confusing with the implementation of delayed RX ACKs.
net/tcp: Initial implementation of TCP delayed ACKs.
net/tcp: Add delayed ACK configuration selection. Rename tcp_ack() to tcp_synack(). It may or may not send a ACK. It will always send SYN or SYN/ACK.
