Commit a0f0e556 authored by Robert Lubos's avatar Robert Lubos Committed by Alberto Escolar
Browse files

net: tcp: Fix FIN with data handling 



In case FIN packet included data bytes, Zephyr would ignore the
data. It wasn't passed to the application, and it wasn't considered
when bumping the ACK counter. This ended out in connection timing out,
instead of being properly terminated.

Fix this, by refactoring FIN processing in TCP_ESTABLISHED state.
Instead of handling FIN/FIN,ACK/FIN,ACK,PSH cases separately, have a
common handler when FIN flag is present, and when ACK flag is present
along with FIN. When FIN is present, take any potentially incoming data
into account.

Signed-off-by: default avatarRobert Lubos <robert.lubos@nordicsemi.no>
parent 2fc42054

subsys/net/ip/tcp.c

+23 −27
Original line number Diff line number Diff line
@@ -2998,30 +2998,9 @@ next_state: 
		break;

	case TCP_ESTABLISHED:

		/* full-close */

		if (th && FL(&fl, ==, (FIN | ACK), th_seq(th) == conn->ack)) {

			if (net_tcp_seq_cmp(th_ack(th), conn->seq) > 0) {

				uint32_t len_acked = th_ack(th) - conn->seq;



				conn_seq(conn, + len_acked);

			}

		if (th && FL(&fl, &, FIN, th_seq(th) == conn->ack)) {

			bool acked = false;



			conn_ack(conn, + 1);

			tcp_out(conn, FIN | ACK);

			conn_seq(conn, + 1);

			next = TCP_LAST_ACK;

			verdict = NET_OK;

			keep_alive_timer_stop(conn);

			tcp_setup_last_ack_timer(conn);

			break;

		} else if (th && FL(&fl, ==, FIN, th_seq(th) == conn->ack)) {

			conn_ack(conn, + 1);

			tcp_out(conn, ACK);

			next = TCP_CLOSE_WAIT;

			verdict = NET_OK;

			keep_alive_timer_stop(conn);

			break;

		} else if (th && FL(&fl, ==, (FIN | ACK | PSH),

				    th_seq(th) == conn->ack)) {

			if (len) {

				verdict = tcp_data_get(conn, pkt, &len);

				if (verdict == NET_OK) {
@@ -3033,11 +3012,28 @@ next_state: 
			}



			conn_ack(conn, + len + 1);

			keep_alive_timer_stop(conn);



			if (FL(&fl, &, ACK)) {

				acked = true;



				if (net_tcp_seq_cmp(th_ack(th), conn->seq) > 0) {

					uint32_t len_acked = th_ack(th) - conn->seq;



					conn_seq(conn, + len_acked);

				}

			}



			if (acked) {

				tcp_out(conn, FIN | ACK);

				conn_seq(conn, + 1);

			next = TCP_LAST_ACK;

			keep_alive_timer_stop(conn);

				tcp_setup_last_ack_timer(conn);

				next = TCP_LAST_ACK;

			} else {

				tcp_out(conn, ACK);

				next = TCP_CLOSE_WAIT;

			}



			break;

		}

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