1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2
  3#ifndef _LINUX_RSTREASON_H
  4#define _LINUX_RSTREASON_H
  5#include <net/dropreason-core.h>
  6#include <uapi/linux/mptcp.h>
  7
  8#define DEFINE_RST_REASON(FN, FNe)	\
  9	FN(NOT_SPECIFIED)		\
 10	FN(NO_SOCKET)			\
 11	FN(TCP_INVALID_ACK_SEQUENCE)	\
 12	FN(TCP_RFC7323_PAWS)		\
 13	FN(TCP_TOO_OLD_ACK)		\
 14	FN(TCP_ACK_UNSENT_DATA)		\
 15	FN(TCP_FLAGS)			\
 16	FN(TCP_OLD_ACK)			\
 17	FN(TCP_ABORT_ON_DATA)		\
 18	FN(TCP_TIMEWAIT_SOCKET)		\
 19	FN(INVALID_SYN)			\
 20	FN(TCP_ABORT_ON_CLOSE)		\
 21	FN(TCP_ABORT_ON_LINGER)		\
 22	FN(TCP_ABORT_ON_MEMORY)		\
 23	FN(TCP_STATE)			\
 24	FN(TCP_KEEPALIVE_TIMEOUT)	\
 25	FN(TCP_DISCONNECT_WITH_DATA)	\
 26	FN(MPTCP_RST_EUNSPEC)		\
 27	FN(MPTCP_RST_EMPTCP)		\
 28	FN(MPTCP_RST_ERESOURCE)		\
 29	FN(MPTCP_RST_EPROHIBIT)		\
 30	FN(MPTCP_RST_EWQ2BIG)		\
 31	FN(MPTCP_RST_EBADPERF)		\
 32	FN(MPTCP_RST_EMIDDLEBOX)	\
 33	FN(ERROR)			\
 34	FNe(MAX)
 35
 36/**
 37 * enum sk_rst_reason - the reasons of socket reset
 38 *
 39 * The reasons of sk reset, which are used in DCCP/TCP/MPTCP protocols.
 40 *
 41 * There are three parts in order:
 42 * 1) skb drop reasons: relying on drop reasons for such as passive reset
 43 * 2) independent reset reasons: such as active reset reasons
 44 * 3) reset reasons in MPTCP: only for MPTCP use
 45 */
 46enum sk_rst_reason {
 47	/* Refer to include/net/dropreason-core.h
 48	 * Rely on skb drop reasons because it indicates exactly why RST
 49	 * could happen.
 50	 */
 51	/** @SK_RST_REASON_NOT_SPECIFIED: reset reason is not specified */
 52	SK_RST_REASON_NOT_SPECIFIED,
 53	/** @SK_RST_REASON_NO_SOCKET: no valid socket that can be used */
 54	SK_RST_REASON_NO_SOCKET,
 55	/**
 56	 * @SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE: Not acceptable ACK SEQ
 57	 * field because ack sequence is not in the window between snd_una
 58	 * and snd_nxt
 59	 */
 60	SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE,
 61	/**
 62	 * @SK_RST_REASON_TCP_RFC7323_PAWS: PAWS check, corresponding to
 63	 * LINUX_MIB_PAWSESTABREJECTED, LINUX_MIB_PAWSACTIVEREJECTED
 64	 */
 65	SK_RST_REASON_TCP_RFC7323_PAWS,
 66	/** @SK_RST_REASON_TCP_TOO_OLD_ACK: TCP ACK is too old */
 67	SK_RST_REASON_TCP_TOO_OLD_ACK,
 68	/**
 69	 * @SK_RST_REASON_TCP_ACK_UNSENT_DATA: TCP ACK for data we haven't
 70	 * sent yet
 71	 */
 72	SK_RST_REASON_TCP_ACK_UNSENT_DATA,
 73	/** @SK_RST_REASON_TCP_FLAGS: TCP flags invalid */
 74	SK_RST_REASON_TCP_FLAGS,
 75	/** @SK_RST_REASON_TCP_OLD_ACK: TCP ACK is old, but in window */
 76	SK_RST_REASON_TCP_OLD_ACK,
 77	/**
 78	 * @SK_RST_REASON_TCP_ABORT_ON_DATA: abort on data
 79	 * corresponding to LINUX_MIB_TCPABORTONDATA
 80	 */
 81	SK_RST_REASON_TCP_ABORT_ON_DATA,
 82
 83	/* Here start with the independent reasons */
 84	/** @SK_RST_REASON_TCP_TIMEWAIT_SOCKET: happen on the timewait socket */
 85	SK_RST_REASON_TCP_TIMEWAIT_SOCKET,
 86	/**
 87	 * @SK_RST_REASON_INVALID_SYN: receive bad syn packet
 88	 * RFC 793 says if the state is not CLOSED/LISTEN/SYN-SENT then
 89	 * "fourth, check the SYN bit,...If the SYN is in the window it is
 90	 * an error, send a reset"
 91	 */
 92	SK_RST_REASON_INVALID_SYN,
 93	/**
 94	 * @SK_RST_REASON_TCP_ABORT_ON_CLOSE: abort on close
 95	 * corresponding to LINUX_MIB_TCPABORTONCLOSE
 96	 */
 97	SK_RST_REASON_TCP_ABORT_ON_CLOSE,
 98	/**
 99	 * @SK_RST_REASON_TCP_ABORT_ON_LINGER: abort on linger
100	 * corresponding to LINUX_MIB_TCPABORTONLINGER
101	 */
102	SK_RST_REASON_TCP_ABORT_ON_LINGER,
103	/**
104	 * @SK_RST_REASON_TCP_ABORT_ON_MEMORY: abort on memory
105	 * corresponding to LINUX_MIB_TCPABORTONMEMORY
106	 */
107	SK_RST_REASON_TCP_ABORT_ON_MEMORY,
108	/**
109	 * @SK_RST_REASON_TCP_STATE: abort on tcp state
110	 * Please see RFC 9293 for all possible reset conditions
111	 */
112	SK_RST_REASON_TCP_STATE,
113	/**
114	 * @SK_RST_REASON_TCP_KEEPALIVE_TIMEOUT: time to timeout
115	 * When we have already run out of all the chances, which means
116	 * keepalive timeout, we have to reset the connection
117	 */
118	SK_RST_REASON_TCP_KEEPALIVE_TIMEOUT,
119	/**
120	 * @SK_RST_REASON_TCP_DISCONNECT_WITH_DATA: disconnect when write
121	 * queue is not empty
122	 * It means user has written data into the write queue when doing
123	 * disconnecting, so we have to send an RST.
124	 */
125	SK_RST_REASON_TCP_DISCONNECT_WITH_DATA,
126
127	/* Copy from include/uapi/linux/mptcp.h.
128	 * These reset fields will not be changed since they adhere to
129	 * RFC 8684. So do not touch them. I'm going to list each definition
130	 * of them respectively.
131	 */
132	/**
133	 * @SK_RST_REASON_MPTCP_RST_EUNSPEC: Unspecified error.
134	 * This is the default error; it implies that the subflow is no
135	 * longer available. The presence of this option shows that the
136	 * RST was generated by an MPTCP-aware device.
137	 */
138	SK_RST_REASON_MPTCP_RST_EUNSPEC,
139	/**
140	 * @SK_RST_REASON_MPTCP_RST_EMPTCP: MPTCP-specific error.
141	 * An error has been detected in the processing of MPTCP options.
142	 * This is the usual reason code to return in the cases where a RST
143	 * is being sent to close a subflow because of an invalid response.
144	 */
145	SK_RST_REASON_MPTCP_RST_EMPTCP,
146	/**
147	 * @SK_RST_REASON_MPTCP_RST_ERESOURCE: Lack of resources.
148	 * This code indicates that the sending host does not have enough
149	 * resources to support the terminated subflow.
150	 */
151	SK_RST_REASON_MPTCP_RST_ERESOURCE,
152	/**
153	 * @SK_RST_REASON_MPTCP_RST_EPROHIBIT: Administratively prohibited.
154	 * This code indicates that the requested subflow is prohibited by
155	 * the policies of the sending host.
156	 */
157	SK_RST_REASON_MPTCP_RST_EPROHIBIT,
158	/**
159	 * @SK_RST_REASON_MPTCP_RST_EWQ2BIG: Too much outstanding data.
160	 * This code indicates that there is an excessive amount of data
161	 * that needs to be transmitted over the terminated subflow while
162	 * having already been acknowledged over one or more other subflows.
163	 * This may occur if a path has been unavailable for a short period
164	 * and it is more efficient to reset and start again than it is to
165	 * retransmit the queued data.
166	 */
167	SK_RST_REASON_MPTCP_RST_EWQ2BIG,
168	/**
169	 * @SK_RST_REASON_MPTCP_RST_EBADPERF: Unacceptable performance.
170	 * This code indicates that the performance of this subflow was
171	 * too low compared to the other subflows of this Multipath TCP
172	 * connection.
173	 */
174	SK_RST_REASON_MPTCP_RST_EBADPERF,
175	/**
176	 * @SK_RST_REASON_MPTCP_RST_EMIDDLEBOX: Middlebox interference.
177	 * Middlebox interference has been detected over this subflow,
178	 * making MPTCP signaling invalid. For example, this may be sent
179	 * if the checksum does not validate.
180	 */
181	SK_RST_REASON_MPTCP_RST_EMIDDLEBOX,
182
183	/** @SK_RST_REASON_ERROR: unexpected error happens */
184	SK_RST_REASON_ERROR,
185
186	/**
187	 * @SK_RST_REASON_MAX: Maximum of socket reset reasons.
188	 * It shouldn't be used as a real 'reason'.
189	 */
190	SK_RST_REASON_MAX,
191};
192
193/* Convert skb drop reasons to enum sk_rst_reason type */
194static inline enum sk_rst_reason
195sk_rst_convert_drop_reason(enum skb_drop_reason reason)
196{
197	switch (reason) {
198	case SKB_DROP_REASON_NOT_SPECIFIED:
199		return SK_RST_REASON_NOT_SPECIFIED;
200	case SKB_DROP_REASON_NO_SOCKET:
201		return SK_RST_REASON_NO_SOCKET;
202	case SKB_DROP_REASON_TCP_INVALID_ACK_SEQUENCE:
203		return SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE;
204	case SKB_DROP_REASON_TCP_RFC7323_PAWS:
205		return SK_RST_REASON_TCP_RFC7323_PAWS;
206	case SKB_DROP_REASON_TCP_TOO_OLD_ACK:
207		return SK_RST_REASON_TCP_TOO_OLD_ACK;
208	case SKB_DROP_REASON_TCP_ACK_UNSENT_DATA:
209		return SK_RST_REASON_TCP_ACK_UNSENT_DATA;
210	case SKB_DROP_REASON_TCP_FLAGS:
211		return SK_RST_REASON_TCP_FLAGS;
212	case SKB_DROP_REASON_TCP_OLD_ACK:
213		return SK_RST_REASON_TCP_OLD_ACK;
214	case SKB_DROP_REASON_TCP_ABORT_ON_DATA:
215		return SK_RST_REASON_TCP_ABORT_ON_DATA;
216	default:
217		/* If we don't have our own corresponding reason */
218		return SK_RST_REASON_NOT_SPECIFIED;
219	}
220}
221#endif