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+/* 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