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net/tcp: Reset the conn when receiving a ACK in the SYN_SENT state. 

According to RFC793, Section 3.4, Page 33. In the SYN_SENT state, if receive a ACK without the SYN, we should reset the connection and retransmit the SYN.

Signed-off-by: liqinhui <liqinhui@xiaomi.com>
This commit is contained in:
liqinhui 2024-09-11 20:50:27 +08:00 committed by Xiang Xiao
parent 243148241a
commit 4c85805be0
1 changed files with 21 additions and 0 deletions
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21
net/tcp/tcp_input.c
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@ -1174,6 +1174,27 @@ found:
seq = tcp_getsequence(tcp->seqno);
rcvseq = tcp_getsequence(conn->rcvseq);
/* According to RFC793, Section 3.4, Page 33.
* In the SYN_SENT state, if receive a ACK without SYN,
* we should reset the connection and retransmit the SYN.
*/
if (((conn->tcpstateflags & TCP_STATE_MASK) == TCP_SYN_SENT) &&
((tcp->flags & TCP_SYN) == 0 && (tcp->flags & TCP_ACK) != 0))
{
/* Send the RST to close the half-open connection. */
tcp_reset(dev, conn);
/* Retransmit the SYN as soon as possible in order to establish
* the tcp connection.
*/
tcp_update_retrantimer(conn, 1);
return;
}
if (seq != rcvseq)
{
/* Trim the head of the segment */