Commit 5cb2cb3c authored by Jason Xing's avatar Jason Xing Committed by Paolo Abeni
Browse files

net: introduce rstreason to detect why the RST is sent 



Add a new standalone file for the easy future extension to support
both active reset and passive reset in the TCP/DCCP/MPTCP protocols.

This patch only does the preparations for reset reason mechanism,
nothing else changes.

The reset reasons are divided into three parts:
1) reuse drop reasons for passive reset in TCP
2) our own independent reasons which aren't relying on other reasons at all
3) reuse MP_TCPRST option for MPTCP

The benefits of a standalone reset reason are listed here:
1) it can cover more than one case, such as reset reasons in MPTCP,
active reset reasons.
2) people can easily/fastly understand and maintain this mechanism.
3) we get unified format of output with prefix stripped.
4) more new reset reasons are on the way
...

I will implement the basic codes of active/passive reset reason in
those three protocols, which are not complete for this moment. For
passive reset part in TCP, I only introduce the NO_SOCKET common case
which could be set as an example.

After this series applied, it will have the ability to open a new
gate to let other people contribute more reasons into it :)

Signed-off-by: default avatarJason Xing <kernelxing@tencent.com>
Acked-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 15fd021b

include/net/rstreason.h

0 → 100644
+106 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-or-later */



#ifndef _LINUX_RSTREASON_H

#define _LINUX_RSTREASON_H

#include <net/dropreason-core.h>

#include <uapi/linux/mptcp.h>



#define DEFINE_RST_REASON(FN, FNe)	\

	FN(NOT_SPECIFIED)		\

	FN(NO_SOCKET)			\

	FN(MPTCP_RST_EUNSPEC)		\

	FN(MPTCP_RST_EMPTCP)		\

	FN(MPTCP_RST_ERESOURCE)		\

	FN(MPTCP_RST_EPROHIBIT)		\

	FN(MPTCP_RST_EWQ2BIG)		\

	FN(MPTCP_RST_EBADPERF)		\

	FN(MPTCP_RST_EMIDDLEBOX)	\

	FN(ERROR)			\

	FNe(MAX)



/**

 * enum sk_rst_reason - the reasons of socket reset

 *

 * The reasons of sk reset, which are used in DCCP/TCP/MPTCP protocols.

 *

 * There are three parts in order:

 * 1) skb drop reasons: relying on drop reasons for such as passive reset

 * 2) independent reset reasons: such as active reset reasons

 * 3) reset reasons in MPTCP: only for MPTCP use

 */

enum sk_rst_reason {

	/* Refer to include/net/dropreason-core.h

	 * Rely on skb drop reasons because it indicates exactly why RST

	 * could happen.

	 */

	/** @SK_RST_REASON_NOT_SPECIFIED: reset reason is not specified */

	SK_RST_REASON_NOT_SPECIFIED,

	/** @SK_RST_REASON_NO_SOCKET: no valid socket that can be used */

	SK_RST_REASON_NO_SOCKET,



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

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

	 * RFC 8684. So do not touch them. I'm going to list each definition

	 * of them respectively.

	 */

	/**

	 * @SK_RST_REASON_MPTCP_RST_EUNSPEC: Unspecified error.

	 * This is the default error; it implies that the subflow is no

	 * longer available. The presence of this option shows that the

	 * RST was generated by an MPTCP-aware device.

	 */

	SK_RST_REASON_MPTCP_RST_EUNSPEC,

	/**

	 * @SK_RST_REASON_MPTCP_RST_EMPTCP: MPTCP-specific error.

	 * An error has been detected in the processing of MPTCP options.

	 * This is the usual reason code to return in the cases where a RST

	 * is being sent to close a subflow because of an invalid response.

	 */

	SK_RST_REASON_MPTCP_RST_EMPTCP,

	/**

	 * @SK_RST_REASON_MPTCP_RST_ERESOURCE: Lack of resources.

	 * This code indicates that the sending host does not have enough

	 * resources to support the terminated subflow.

	 */

	SK_RST_REASON_MPTCP_RST_ERESOURCE,

	/**

	 * @SK_RST_REASON_MPTCP_RST_EPROHIBIT: Administratively prohibited.

	 * This code indicates that the requested subflow is prohibited by

	 * the policies of the sending host.

	 */

	SK_RST_REASON_MPTCP_RST_EPROHIBIT,

	/**

	 * @SK_RST_REASON_MPTCP_RST_EWQ2BIG: Too much outstanding data.

	 * This code indicates that there is an excessive amount of data

	 * that needs to be transmitted over the terminated subflow while

	 * having already been acknowledged over one or more other subflows.

	 * This may occur if a path has been unavailable for a short period

	 * and it is more efficient to reset and start again than it is to

	 * retransmit the queued data.

	 */

	SK_RST_REASON_MPTCP_RST_EWQ2BIG,

	/**

	 * @SK_RST_REASON_MPTCP_RST_EBADPERF: Unacceptable performance.

	 * This code indicates that the performance of this subflow was

	 * too low compared to the other subflows of this Multipath TCP

	 * connection.

	 */

	SK_RST_REASON_MPTCP_RST_EBADPERF,

	/**

	 * @SK_RST_REASON_MPTCP_RST_EMIDDLEBOX: Middlebox interference.

	 * Middlebox interference has been detected over this subflow,

	 * making MPTCP signaling invalid. For example, this may be sent

	 * if the checksum does not validate.

	 */

	SK_RST_REASON_MPTCP_RST_EMIDDLEBOX,



	/** @SK_RST_REASON_ERROR: unexpected error happens */

	SK_RST_REASON_ERROR,



	/**

	 * @SK_RST_REASON_MAX: Maximum of socket reset reasons.

	 * It shouldn't be used as a real 'reason'.

	 */

	SK_RST_REASON_MAX,

};

#endif