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tcp_input: if tcp->req > recvreq, send ack only when state is TCP_ESTABLISHED

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The Bluetooth network on N62 does not retransmit packet, so no packet
retransmition if we drop one, we will drop packet when tcp_close_eventhandler
is register and invoke by tcp_input. then we will always early return and
never stop, the peer will only close the connection if we send reset packet.

precondition:
close -> register tcp_close_eventhandler;

tcp_input -> tcp_callback(TCP_NEWDATA) -> devif_conn_event -> tcp_close_eventhandler
-> flags &= ~TCP_NEWDATA -> NOT entry tcp_data_event -> conn->recvreq NOT increase

old flow:
tcp_input -> tcp->seqno greater than conn->rcvseq -> tcp_send(TCP_ACK)

with this patch:
tcp_input -> tcp->seqno greater than conn->rcvseq -> !TCP_ESTABLISHED
-> case TCP_FIN_WAIT_1 -> dev->d_len greater than 0 -> tcp_reset

Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
This commit is contained in:
zhanghongyu 2023-08-31 19:31:31 +08:00 committed by Petro Karashchenko
parent 5fedb1e6de
commit 3c4897310b
1 changed files with 5 additions and 2 deletions
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7
net/tcp/tcp_input.c
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@ -1185,8 +1185,11 @@ found:
tcp_input_ofosegs(dev, conn, iplen);
#endif
tcp_send(dev, conn, TCP_ACK, tcpiplen);
return;
if ((conn->tcpstateflags & TCP_STATE_MASK) <= TCP_ESTABLISHED)
{
tcp_send(dev, conn, TCP_ACK, tcpiplen);
return;
}
}
}
}