Commit edefba66 authored by Jason Xing's avatar Jason Xing Committed by David S. Miller
Browse files

tcp: rstreason: introduce SK_RST_REASON_TCP_STATE for active reset 



Introducing a new type TCP_STATE to handle some reset conditions
appearing in RFC 793 due to its socket state. Actually, we can look
into RFC 9293 which has no discrepancy about this part.

Signed-off-by: default avatarJason Xing <kernelxing@tencent.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8407994f

include/net/rstreason.h

+6 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
	FN(TCP_ABORT_ON_CLOSE)		\

	FN(TCP_ABORT_ON_LINGER)		\

	FN(TCP_ABORT_ON_MEMORY)		\

	FN(TCP_STATE)			\

	FN(MPTCP_RST_EUNSPEC)		\

	FN(MPTCP_RST_EMPTCP)		\

	FN(MPTCP_RST_ERESOURCE)		\
@@ -102,6 +103,11 @@ enum sk_rst_reason { 
	 * corresponding to LINUX_MIB_TCPABORTONMEMORY

	 */

	SK_RST_REASON_TCP_ABORT_ON_MEMORY,

	/**

	 * @SK_RST_REASON_TCP_STATE: abort on tcp state

	 * Please see RFC 9293 for all possible reset conditions

	 */

	SK_RST_REASON_TCP_STATE,



	/* Copy from include/uapi/linux/mptcp.h.

	 * These reset fields will not be changed since they adhere to

net/ipv4/tcp.c

+6 −4
Original line number Diff line number Diff line
@@ -3025,9 +3025,11 @@ int tcp_disconnect(struct sock *sk, int flags) 
		inet_csk_listen_stop(sk);

	} else if (unlikely(tp->repair)) {

		WRITE_ONCE(sk->sk_err, ECONNABORTED);

	} else if (tcp_need_reset(old_state) ||

		   (tp->snd_nxt != tp->write_seq &&

		    (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {

	} else if (tcp_need_reset(old_state)) {

		tcp_send_active_reset(sk, gfp_any(), SK_RST_REASON_TCP_STATE);

		WRITE_ONCE(sk->sk_err, ECONNRESET);

	} else if (tp->snd_nxt != tp->write_seq &&

		   (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {

		/* The last check adjusts for discrepancy of Linux wrt. RFC

		 * states

		 */
@@ -4649,7 +4651,7 @@ int tcp_abort(struct sock *sk, int err) 
	if (!sock_flag(sk, SOCK_DEAD)) {

		if (tcp_need_reset(sk->sk_state))

			tcp_send_active_reset(sk, GFP_ATOMIC,

					      SK_RST_REASON_NOT_SPECIFIED);

					      SK_RST_REASON_TCP_STATE);

		tcp_done_with_error(sk, err);

	}

net/ipv4/tcp_timer.c

+1 −1
Original line number Diff line number Diff line
@@ -779,7 +779,7 @@ static void tcp_keepalive_timer (struct timer_list *t) 
				goto out;

			}

		}

		tcp_send_active_reset(sk, GFP_ATOMIC, SK_RST_REASON_NOT_SPECIFIED);

		tcp_send_active_reset(sk, GFP_ATOMIC, SK_RST_REASON_TCP_STATE);

		goto death;

	}