xref: /linux/net/mptcp/protocol.h (revision 6490dda55dcabbd5cf408387f932c9343a22c872)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Multipath TCP
3  *
4  * Copyright (c) 2017 - 2019, Intel Corporation.
5  */
6 
7 #ifndef __MPTCP_PROTOCOL_H
8 #define __MPTCP_PROTOCOL_H
9 
10 #include <linux/random.h>
11 #include <net/tcp.h>
12 #include <net/inet_connection_sock.h>
13 #include <uapi/linux/mptcp.h>
14 #include <net/genetlink.h>
15 #include <net/rstreason.h>
16 
17 #define MPTCP_SUPPORTED_VERSION	1
18 
19 /* MPTCP option bits */
20 #define OPTION_MPTCP_MPC_SYN	BIT(0)
21 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
22 #define OPTION_MPTCP_MPC_ACK	BIT(2)
23 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
24 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
25 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
26 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
27 #define OPTION_MPTCP_RM_ADDR	BIT(7)
28 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
29 #define OPTION_MPTCP_PRIO	BIT(9)
30 #define OPTION_MPTCP_RST	BIT(10)
31 #define OPTION_MPTCP_DSS	BIT(11)
32 #define OPTION_MPTCP_FAIL	BIT(12)
33 
34 #define OPTION_MPTCP_CSUMREQD	BIT(13)
35 
36 #define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
37 				 OPTION_MPTCP_MPC_ACK)
38 #define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
39 				 OPTION_MPTCP_MPJ_ACK)
40 
41 /* MPTCP option subtypes */
42 #define MPTCPOPT_MP_CAPABLE	0
43 #define MPTCPOPT_MP_JOIN	1
44 #define MPTCPOPT_DSS		2
45 #define MPTCPOPT_ADD_ADDR	3
46 #define MPTCPOPT_RM_ADDR	4
47 #define MPTCPOPT_MP_PRIO	5
48 #define MPTCPOPT_MP_FAIL	6
49 #define MPTCPOPT_MP_FASTCLOSE	7
50 #define MPTCPOPT_RST		8
51 
52 /* MPTCP suboption lengths */
53 #define TCPOLEN_MPTCP_MPC_SYN		4
54 #define TCPOLEN_MPTCP_MPC_SYNACK	12
55 #define TCPOLEN_MPTCP_MPC_ACK		20
56 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
57 #define TCPOLEN_MPTCP_MPJ_SYN		12
58 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
59 #define TCPOLEN_MPTCP_MPJ_ACK		24
60 #define TCPOLEN_MPTCP_DSS_BASE		4
61 #define TCPOLEN_MPTCP_DSS_ACK32		4
62 #define TCPOLEN_MPTCP_DSS_ACK64		8
63 #define TCPOLEN_MPTCP_DSS_MAP32		10
64 #define TCPOLEN_MPTCP_DSS_MAP64		14
65 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
66 #define TCPOLEN_MPTCP_ADD_ADDR		16
67 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
68 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
69 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
70 #define TCPOLEN_MPTCP_ADD_ADDR6		28
71 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
72 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
73 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
74 #define TCPOLEN_MPTCP_PORT_LEN		2
75 #define TCPOLEN_MPTCP_PORT_ALIGN	2
76 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
77 #define TCPOLEN_MPTCP_PRIO		3
78 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
79 #define TCPOLEN_MPTCP_FASTCLOSE		12
80 #define TCPOLEN_MPTCP_RST		4
81 #define TCPOLEN_MPTCP_FAIL		12
82 
83 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
84 
85 /* MPTCP MP_JOIN flags */
86 #define MPTCPOPT_BACKUP		BIT(0)
87 #define MPTCPOPT_THMAC_LEN	8
88 
89 /* MPTCP MP_CAPABLE flags */
90 #define MPTCP_VERSION_MASK	(0x0F)
91 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
92 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
93 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
94 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
95 #define MPTCP_CAP_FLAG_MASK	(0x1F)
96 
97 /* MPTCP DSS flags */
98 #define MPTCP_DSS_DATA_FIN	BIT(4)
99 #define MPTCP_DSS_DSN64		BIT(3)
100 #define MPTCP_DSS_HAS_MAP	BIT(2)
101 #define MPTCP_DSS_ACK64		BIT(1)
102 #define MPTCP_DSS_HAS_ACK	BIT(0)
103 #define MPTCP_DSS_FLAG_MASK	(0x1F)
104 
105 /* MPTCP ADD_ADDR flags */
106 #define MPTCP_ADDR_ECHO		BIT(0)
107 
108 /* MPTCP MP_PRIO flags */
109 #define MPTCP_PRIO_BKUP		BIT(0)
110 
111 /* MPTCP TCPRST flags */
112 #define MPTCP_RST_TRANSIENT	BIT(0)
113 
114 /* MPTCP socket atomic flags */
115 #define MPTCP_WORK_RTX		1
116 #define MPTCP_FALLBACK_DONE	2
117 #define MPTCP_WORK_CLOSE_SUBFLOW 3
118 
119 /* MPTCP socket release cb flags */
120 #define MPTCP_PUSH_PENDING	1
121 #define MPTCP_CLEAN_UNA		2
122 #define MPTCP_ERROR_REPORT	3
123 #define MPTCP_RETRANSMIT	4
124 #define MPTCP_FLUSH_JOIN_LIST	5
125 #define MPTCP_SYNC_STATE	6
126 #define MPTCP_SYNC_SNDBUF	7
127 
128 struct mptcp_skb_cb {
129 	u64 map_seq;
130 	u64 end_seq;
131 	u32 offset;
132 	u8  has_rxtstamp:1;
133 };
134 
135 #define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
136 
137 static inline bool before64(__u64 seq1, __u64 seq2)
138 {
139 	return (__s64)(seq1 - seq2) < 0;
140 }
141 
142 #define after64(seq2, seq1)	before64(seq1, seq2)
143 
144 struct mptcp_options_received {
145 	u64	sndr_key;
146 	u64	rcvr_key;
147 	u64	data_ack;
148 	u64	data_seq;
149 	u32	subflow_seq;
150 	u16	data_len;
151 	__sum16	csum;
152 	u16	suboptions;
153 	u32	token;
154 	u32	nonce;
155 	u16	use_map:1,
156 		dsn64:1,
157 		data_fin:1,
158 		use_ack:1,
159 		ack64:1,
160 		mpc_map:1,
161 		reset_reason:4,
162 		reset_transient:1,
163 		echo:1,
164 		backup:1,
165 		deny_join_id0:1,
166 		__unused:2;
167 	u8	join_id;
168 	u64	thmac;
169 	u8	hmac[MPTCPOPT_HMAC_LEN];
170 	struct mptcp_addr_info addr;
171 	struct mptcp_rm_list rm_list;
172 	u64	ahmac;
173 	u64	fail_seq;
174 };
175 
176 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
177 {
178 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
179 		     ((nib & 0xF) << 8) | field);
180 }
181 
182 enum mptcp_pm_status {
183 	MPTCP_PM_ADD_ADDR_RECEIVED,
184 	MPTCP_PM_ADD_ADDR_SEND_ACK,
185 	MPTCP_PM_RM_ADDR_RECEIVED,
186 	MPTCP_PM_ESTABLISHED,
187 	MPTCP_PM_SUBFLOW_ESTABLISHED,
188 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
189 	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
190 					 * accounted int id_avail_bitmap
191 					 */
192 };
193 
194 enum mptcp_pm_type {
195 	MPTCP_PM_TYPE_KERNEL = 0,
196 	MPTCP_PM_TYPE_USERSPACE,
197 
198 	__MPTCP_PM_TYPE_NR,
199 	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
200 };
201 
202 /* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */
203 #define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)
204 
205 enum mptcp_addr_signal_status {
206 	MPTCP_ADD_ADDR_SIGNAL,
207 	MPTCP_ADD_ADDR_ECHO,
208 	MPTCP_RM_ADDR_SIGNAL,
209 };
210 
211 /* max value of mptcp_addr_info.id */
212 #define MPTCP_PM_MAX_ADDR_ID		U8_MAX
213 
214 struct mptcp_pm_data {
215 	struct mptcp_addr_info local;
216 	struct mptcp_addr_info remote;
217 	struct list_head anno_list;
218 	struct list_head userspace_pm_local_addr_list;
219 
220 	spinlock_t	lock;		/*protects the whole PM data */
221 
222 	u8		addr_signal;
223 	bool		server_side;
224 	bool		work_pending;
225 	bool		accept_addr;
226 	bool		accept_subflow;
227 	bool		remote_deny_join_id0;
228 	u8		add_addr_signaled;
229 	u8		add_addr_accepted;
230 	u8		local_addr_used;
231 	u8		pm_type;
232 	u8		subflows;
233 	u8		status;
234 	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
235 	struct mptcp_rm_list rm_list_tx;
236 	struct mptcp_rm_list rm_list_rx;
237 };
238 
239 struct mptcp_pm_addr_entry {
240 	struct list_head	list;
241 	struct mptcp_addr_info	addr;
242 	u8			flags;
243 	int			ifindex;
244 	struct socket		*lsk;
245 };
246 
247 struct mptcp_data_frag {
248 	struct list_head list;
249 	u64 data_seq;
250 	u16 data_len;
251 	u16 offset;
252 	u16 overhead;
253 	u16 already_sent;
254 	struct page *page;
255 };
256 
257 /* MPTCP connection sock */
258 struct mptcp_sock {
259 	/* inet_connection_sock must be the first member */
260 	struct inet_connection_sock sk;
261 	u64		local_key;		/* protected by the first subflow socket lock
262 						 * lockless access read
263 						 */
264 	u64		remote_key;		/* same as above */
265 	u64		write_seq;
266 	u64		bytes_sent;
267 	u64		snd_nxt;
268 	u64		bytes_received;
269 	u64		ack_seq;
270 	atomic64_t	rcv_wnd_sent;
271 	u64		rcv_data_fin_seq;
272 	u64		bytes_retrans;
273 	u64		bytes_consumed;
274 	int		rmem_fwd_alloc;
275 	int		snd_burst;
276 	int		old_wspace;
277 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
278 						 * recovery related fields are under data_lock
279 						 * protection
280 						 */
281 	u64		bytes_acked;
282 	u64		snd_una;
283 	u64		wnd_end;
284 	u32		last_data_sent;
285 	u32		last_data_recv;
286 	u32		last_ack_recv;
287 	unsigned long	timer_ival;
288 	u32		token;
289 	int		rmem_released;
290 	unsigned long	flags;
291 	unsigned long	cb_flags;
292 	bool		recovery;		/* closing subflow write queue reinjected */
293 	bool		can_ack;
294 	bool		fully_established;
295 	bool		rcv_data_fin;
296 	bool		snd_data_fin_enable;
297 	bool		rcv_fastclose;
298 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
299 	bool		csum_enabled;
300 	bool		allow_infinite_fallback;
301 	u8		pending_state; /* A subflow asked to set this sk_state,
302 					* protected by the msk data lock
303 					*/
304 	u8		mpc_endpoint_id;
305 	u8		recvmsg_inq:1,
306 			cork:1,
307 			nodelay:1,
308 			fastopening:1,
309 			in_accept_queue:1,
310 			free_first:1,
311 			rcvspace_init:1;
312 	u32		notsent_lowat;
313 	int		keepalive_cnt;
314 	int		keepalive_idle;
315 	int		keepalive_intvl;
316 	struct work_struct work;
317 	struct sk_buff  *ooo_last_skb;
318 	struct rb_root  out_of_order_queue;
319 	struct sk_buff_head receive_queue;
320 	struct list_head conn_list;
321 	struct list_head rtx_queue;
322 	struct mptcp_data_frag *first_pending;
323 	struct list_head join_list;
324 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
325 				 * ONCE annotation, the subflow outside the socket
326 				 * lock as such sock is freed after close().
327 				 */
328 	struct mptcp_pm_data	pm;
329 	struct mptcp_sched_ops	*sched;
330 	struct {
331 		u32	space;	/* bytes copied in last measurement window */
332 		u32	copied; /* bytes copied in this measurement window */
333 		u64	time;	/* start time of measurement window */
334 		u64	rtt_us; /* last maximum rtt of subflows */
335 	} rcvq_space;
336 	u8		scaling_ratio;
337 
338 	u32		subflow_id;
339 	u32		setsockopt_seq;
340 	char		ca_name[TCP_CA_NAME_MAX];
341 };
342 
343 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
344 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
345 
346 #define mptcp_for_each_subflow(__msk, __subflow)			\
347 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
348 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
349 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
350 
351 extern struct genl_family mptcp_genl_family;
352 
353 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
354 {
355 	sock_owned_by_me((const struct sock *)msk);
356 }
357 
358 #ifdef CONFIG_DEBUG_NET
359 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
360 #undef tcp_sk
361 #define tcp_sk(ptr) ({								\
362 	typeof(ptr) _ptr = (ptr);						\
363 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
364 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
365 })
366 #define mptcp_sk(ptr) ({						\
367 	typeof(ptr) _ptr = (ptr);					\
368 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
369 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
370 })
371 
372 #else /* !CONFIG_DEBUG_NET */
373 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
374 #endif
375 
376 /* the msk socket don't use the backlog, also account for the bulk
377  * free memory
378  */
379 static inline int __mptcp_rmem(const struct sock *sk)
380 {
381 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
382 }
383 
384 static inline int mptcp_win_from_space(const struct sock *sk, int space)
385 {
386 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
387 }
388 
389 static inline int mptcp_space_from_win(const struct sock *sk, int win)
390 {
391 	return __tcp_space_from_win(mptcp_sk(sk)->scaling_ratio, win);
392 }
393 
394 static inline int __mptcp_space(const struct sock *sk)
395 {
396 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
397 }
398 
399 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
400 {
401 	const struct mptcp_sock *msk = mptcp_sk(sk);
402 
403 	return READ_ONCE(msk->first_pending);
404 }
405 
406 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
407 {
408 	struct mptcp_sock *msk = mptcp_sk(sk);
409 	struct mptcp_data_frag *cur;
410 
411 	cur = msk->first_pending;
412 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
413 						     list_next_entry(cur, list);
414 }
415 
416 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
417 {
418 	const struct mptcp_sock *msk = mptcp_sk(sk);
419 
420 	if (!msk->first_pending)
421 		return NULL;
422 
423 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
424 		return NULL;
425 
426 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
427 }
428 
429 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
430 {
431 	struct mptcp_sock *msk = mptcp_sk(sk);
432 
433 	if (msk->snd_una == msk->snd_nxt)
434 		return NULL;
435 
436 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
437 }
438 
439 struct csum_pseudo_header {
440 	__be64 data_seq;
441 	__be32 subflow_seq;
442 	__be16 data_len;
443 	__sum16 csum;
444 };
445 
446 struct mptcp_subflow_request_sock {
447 	struct	tcp_request_sock sk;
448 	u16	mp_capable : 1,
449 		mp_join : 1,
450 		backup : 1,
451 		request_bkup : 1,
452 		csum_reqd : 1,
453 		allow_join_id0 : 1;
454 	u8	local_id;
455 	u8	remote_id;
456 	u64	local_key;
457 	u64	idsn;
458 	u32	token;
459 	u32	ssn_offset;
460 	u64	thmac;
461 	u32	local_nonce;
462 	u32	remote_nonce;
463 	struct mptcp_sock	*msk;
464 	struct hlist_nulls_node token_node;
465 };
466 
467 static inline struct mptcp_subflow_request_sock *
468 mptcp_subflow_rsk(const struct request_sock *rsk)
469 {
470 	return (struct mptcp_subflow_request_sock *)rsk;
471 }
472 
473 struct mptcp_delegated_action {
474 	struct napi_struct napi;
475 	struct list_head head;
476 };
477 
478 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
479 
480 #define MPTCP_DELEGATE_SCHEDULED	0
481 #define MPTCP_DELEGATE_SEND		1
482 #define MPTCP_DELEGATE_ACK		2
483 #define MPTCP_DELEGATE_SNDBUF		3
484 
485 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
486 /* MPTCP subflow context */
487 struct mptcp_subflow_context {
488 	struct	list_head node;/* conn_list of subflows */
489 
490 	struct_group(reset,
491 
492 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
493 	u64	local_key;
494 	u64	remote_key;
495 	u64	idsn;
496 	u64	map_seq;
497 	u32	snd_isn;
498 	u32	token;
499 	u32	rel_write_seq;
500 	u32	map_subflow_seq;
501 	u32	ssn_offset;
502 	u32	map_data_len;
503 	__wsum	map_data_csum;
504 	u32	map_csum_len;
505 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
506 		request_join : 1,   /* send MP_JOIN */
507 		request_bkup : 1,
508 		mp_capable : 1,	    /* remote is MPTCP capable */
509 		mp_join : 1,	    /* remote is JOINing */
510 		fully_established : 1,	    /* path validated */
511 		pm_notified : 1,    /* PM hook called for established status */
512 		conn_finished : 1,
513 		map_valid : 1,
514 		map_csum_reqd : 1,
515 		map_data_fin : 1,
516 		mpc_map : 1,
517 		backup : 1,
518 		send_mp_prio : 1,
519 		send_mp_fail : 1,
520 		send_fastclose : 1,
521 		send_infinite_map : 1,
522 		remote_key_valid : 1,        /* received the peer key from */
523 		disposable : 1,	    /* ctx can be free at ulp release time */
524 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
525 		valid_csum_seen : 1,        /* at least one csum validated */
526 		is_mptfo : 1,	    /* subflow is doing TFO */
527 		close_event_done : 1,       /* has done the post-closed part */
528 		__unused : 9;
529 	bool	data_avail;
530 	bool	scheduled;
531 	u32	remote_nonce;
532 	u64	thmac;
533 	u32	local_nonce;
534 	u32	remote_token;
535 	union {
536 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
537 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
538 	};
539 	s16	local_id;	    /* if negative not initialized yet */
540 	u8	remote_id;
541 	u8	reset_seen:1;
542 	u8	reset_transient:1;
543 	u8	reset_reason:4;
544 	u8	stale_count;
545 
546 	u32	subflow_id;
547 
548 	long	delegated_status;
549 	unsigned long	fail_tout;
550 
551 	);
552 
553 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
554 
555 	u32	setsockopt_seq;
556 	u32	stale_rcv_tstamp;
557 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
558 				     * protected by the msk socket lock
559 				     */
560 
561 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
562 	struct	sock *conn;	    /* parent mptcp_sock */
563 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
564 	void	(*tcp_state_change)(struct sock *sk);
565 	void	(*tcp_error_report)(struct sock *sk);
566 
567 	struct	rcu_head rcu;
568 };
569 
570 static inline struct mptcp_subflow_context *
571 mptcp_subflow_ctx(const struct sock *sk)
572 {
573 	const struct inet_connection_sock *icsk = inet_csk(sk);
574 
575 	/* Use RCU on icsk_ulp_data only for sock diag code */
576 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
577 }
578 
579 static inline struct sock *
580 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
581 {
582 	return subflow->tcp_sock;
583 }
584 
585 static inline void
586 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
587 {
588 	memset(&subflow->reset, 0, sizeof(subflow->reset));
589 	subflow->request_mptcp = 1;
590 	WRITE_ONCE(subflow->local_id, -1);
591 }
592 
593 /* Convert reset reasons in MPTCP to enum sk_rst_reason type */
594 static inline enum sk_rst_reason
595 sk_rst_convert_mptcp_reason(u32 reason)
596 {
597 	switch (reason) {
598 	case MPTCP_RST_EUNSPEC:
599 		return SK_RST_REASON_MPTCP_RST_EUNSPEC;
600 	case MPTCP_RST_EMPTCP:
601 		return SK_RST_REASON_MPTCP_RST_EMPTCP;
602 	case MPTCP_RST_ERESOURCE:
603 		return SK_RST_REASON_MPTCP_RST_ERESOURCE;
604 	case MPTCP_RST_EPROHIBIT:
605 		return SK_RST_REASON_MPTCP_RST_EPROHIBIT;
606 	case MPTCP_RST_EWQ2BIG:
607 		return SK_RST_REASON_MPTCP_RST_EWQ2BIG;
608 	case MPTCP_RST_EBADPERF:
609 		return SK_RST_REASON_MPTCP_RST_EBADPERF;
610 	case MPTCP_RST_EMIDDLEBOX:
611 		return SK_RST_REASON_MPTCP_RST_EMIDDLEBOX;
612 	default:
613 		/* It should not happen, or else errors may occur
614 		 * in MPTCP layer
615 		 */
616 		return SK_RST_REASON_ERROR;
617 	}
618 }
619 
620 static inline void
621 mptcp_send_active_reset_reason(struct sock *sk)
622 {
623 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
624 	enum sk_rst_reason reason;
625 
626 	reason = sk_rst_convert_mptcp_reason(subflow->reset_reason);
627 	tcp_send_active_reset(sk, GFP_ATOMIC, reason);
628 }
629 
630 static inline u64
631 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
632 {
633 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
634 		      subflow->ssn_offset -
635 		      subflow->map_subflow_seq;
636 }
637 
638 static inline u64
639 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
640 {
641 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
642 }
643 
644 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
645 
646 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
647 {
648 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
649 	struct mptcp_delegated_action *delegated;
650 	bool schedule;
651 
652 	/* the caller held the subflow bh socket lock */
653 	lockdep_assert_in_softirq();
654 
655 	/* The implied barrier pairs with tcp_release_cb_override()
656 	 * mptcp_napi_poll(), and ensures the below list check sees list
657 	 * updates done prior to delegated status bits changes
658 	 */
659 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
660 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
661 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
662 			return;
663 
664 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
665 		schedule = list_empty(&delegated->head);
666 		list_add_tail(&subflow->delegated_node, &delegated->head);
667 		sock_hold(mptcp_subflow_tcp_sock(subflow));
668 		if (schedule)
669 			napi_schedule(&delegated->napi);
670 	}
671 }
672 
673 static inline struct mptcp_subflow_context *
674 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
675 {
676 	struct mptcp_subflow_context *ret;
677 
678 	if (list_empty(&delegated->head))
679 		return NULL;
680 
681 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
682 	list_del_init(&ret->delegated_node);
683 	return ret;
684 }
685 
686 int mptcp_is_enabled(const struct net *net);
687 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
688 int mptcp_is_checksum_enabled(const struct net *net);
689 int mptcp_allow_join_id0(const struct net *net);
690 unsigned int mptcp_stale_loss_cnt(const struct net *net);
691 unsigned int mptcp_close_timeout(const struct sock *sk);
692 int mptcp_get_pm_type(const struct net *net);
693 const char *mptcp_get_scheduler(const struct net *net);
694 void mptcp_get_available_schedulers(char *buf, size_t maxlen);
695 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
696 				       struct mptcp_subflow_context *subflow,
697 				       const struct mptcp_options_received *mp_opt);
698 bool __mptcp_retransmit_pending_data(struct sock *sk);
699 void mptcp_check_and_set_pending(struct sock *sk);
700 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
701 bool mptcp_subflow_data_available(struct sock *sk);
702 void __init mptcp_subflow_init(void);
703 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
704 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
705 		     struct mptcp_subflow_context *subflow);
706 void __mptcp_subflow_send_ack(struct sock *ssk);
707 void mptcp_subflow_reset(struct sock *ssk);
708 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
709 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
710 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
711 bool __mptcp_close(struct sock *sk, long timeout);
712 void mptcp_cancel_work(struct sock *sk);
713 void __mptcp_unaccepted_force_close(struct sock *sk);
714 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
715 void mptcp_set_state(struct sock *sk, int state);
716 
717 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
718 			   const struct mptcp_addr_info *b, bool use_port);
719 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
720 
721 /* called with sk socket lock held */
722 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
723 			    const struct mptcp_addr_info *remote);
724 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
725 				struct socket **new_sock);
726 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
727 			 struct sockaddr_storage *addr,
728 			 unsigned short family);
729 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
730 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
731 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
732 void mptcp_sched_init(void);
733 int mptcp_init_sched(struct mptcp_sock *msk,
734 		     struct mptcp_sched_ops *sched);
735 void mptcp_release_sched(struct mptcp_sock *msk);
736 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
737 				 bool scheduled);
738 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
739 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
740 int mptcp_sched_get_send(struct mptcp_sock *msk);
741 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
742 
743 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
744 {
745 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
746 }
747 
748 static inline bool mptcp_epollin_ready(const struct sock *sk)
749 {
750 	/* mptcp doesn't have to deal with small skbs in the receive queue,
751 	 * at it can always coalesce them
752 	 */
753 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
754 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
755 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
756 	       READ_ONCE(tcp_memory_pressure);
757 }
758 
759 int mptcp_set_rcvlowat(struct sock *sk, int val);
760 
761 static inline bool __tcp_can_send(const struct sock *ssk)
762 {
763 	/* only send if our side has not closed yet */
764 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
765 }
766 
767 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
768 {
769 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
770 	if (subflow->request_join && !subflow->fully_established)
771 		return false;
772 
773 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
774 }
775 
776 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
777 
778 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
779 
780 void mptcp_subflow_drop_ctx(struct sock *ssk);
781 
782 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
783 					      struct mptcp_subflow_context *ctx)
784 {
785 	sk->sk_data_ready = sock_def_readable;
786 	sk->sk_state_change = ctx->tcp_state_change;
787 	sk->sk_write_space = sk_stream_write_space;
788 	sk->sk_error_report = ctx->tcp_error_report;
789 
790 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
791 }
792 
793 void __init mptcp_proto_init(void);
794 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
795 int __init mptcp_proto_v6_init(void);
796 #endif
797 
798 struct sock *mptcp_sk_clone_init(const struct sock *sk,
799 				 const struct mptcp_options_received *mp_opt,
800 				 struct sock *ssk,
801 				 struct request_sock *req);
802 void mptcp_get_options(const struct sk_buff *skb,
803 		       struct mptcp_options_received *mp_opt);
804 
805 void mptcp_finish_connect(struct sock *sk);
806 void __mptcp_sync_state(struct sock *sk, int state);
807 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
808 
809 static inline void mptcp_stop_tout_timer(struct sock *sk)
810 {
811 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
812 		return;
813 
814 	sk_stop_timer(sk, &sk->sk_timer);
815 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
816 }
817 
818 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
819 {
820 	/* avoid 0 timestamp, as that means no close timeout */
821 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
822 }
823 
824 static inline void mptcp_start_tout_timer(struct sock *sk)
825 {
826 	mptcp_set_close_tout(sk, tcp_jiffies32);
827 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
828 }
829 
830 static inline bool mptcp_is_fully_established(struct sock *sk)
831 {
832 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
833 	       READ_ONCE(mptcp_sk(sk)->fully_established);
834 }
835 
836 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
837 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
838 bool mptcp_finish_join(struct sock *sk);
839 bool mptcp_schedule_work(struct sock *sk);
840 int mptcp_setsockopt(struct sock *sk, int level, int optname,
841 		     sockptr_t optval, unsigned int optlen);
842 int mptcp_getsockopt(struct sock *sk, int level, int optname,
843 		     char __user *optval, int __user *option);
844 
845 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
846 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
847 {
848 	if (use_64bit)
849 		return cur_seq;
850 
851 	return __mptcp_expand_seq(old_seq, cur_seq);
852 }
853 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
854 void __mptcp_data_acked(struct sock *sk);
855 void __mptcp_error_report(struct sock *sk);
856 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
857 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
858 {
859 	return READ_ONCE(msk->snd_data_fin_enable) &&
860 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
861 }
862 
863 static inline u32 mptcp_notsent_lowat(const struct sock *sk)
864 {
865 	struct net *net = sock_net(sk);
866 	u32 val;
867 
868 	val = READ_ONCE(mptcp_sk(sk)->notsent_lowat);
869 	return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
870 }
871 
872 static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake)
873 {
874 	const struct mptcp_sock *msk = mptcp_sk(sk);
875 	u32 notsent_bytes;
876 
877 	notsent_bytes = READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt);
878 	return (notsent_bytes << wake) < mptcp_notsent_lowat(sk);
879 }
880 
881 static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake)
882 {
883 	return mptcp_stream_memory_free(sk, wake) &&
884 	       __sk_stream_is_writeable(sk, wake);
885 }
886 
887 static inline void mptcp_write_space(struct sock *sk)
888 {
889 	/* pairs with memory barrier in mptcp_poll */
890 	smp_mb();
891 	if (mptcp_stream_memory_free(sk, 1))
892 		sk_stream_write_space(sk);
893 }
894 
895 static inline void __mptcp_sync_sndbuf(struct sock *sk)
896 {
897 	struct mptcp_subflow_context *subflow;
898 	int ssk_sndbuf, new_sndbuf;
899 
900 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
901 		return;
902 
903 	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
904 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
905 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
906 
907 		subflow->cached_sndbuf = ssk_sndbuf;
908 		new_sndbuf += ssk_sndbuf;
909 	}
910 
911 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
912 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
913 	mptcp_write_space(sk);
914 }
915 
916 /* The called held both the msk socket and the subflow socket locks,
917  * possibly under BH
918  */
919 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
920 {
921 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
922 
923 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
924 		__mptcp_sync_sndbuf(sk);
925 }
926 
927 /* the caller held only the subflow socket lock, either in process or
928  * BH context. Additionally this can be called under the msk data lock,
929  * so we can't acquire such lock here: let the delegate action acquires
930  * the needed locks in suitable order.
931  */
932 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
933 {
934 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
935 
936 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
937 		return;
938 
939 	local_bh_disable();
940 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
941 	local_bh_enable();
942 }
943 
944 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
945 
946 #define MPTCP_TOKEN_MAX_RETRIES	4
947 
948 void __init mptcp_token_init(void);
949 static inline void mptcp_token_init_request(struct request_sock *req)
950 {
951 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
952 }
953 
954 int mptcp_token_new_request(struct request_sock *req);
955 void mptcp_token_destroy_request(struct request_sock *req);
956 int mptcp_token_new_connect(struct sock *ssk);
957 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
958 			struct mptcp_sock *msk);
959 bool mptcp_token_exists(u32 token);
960 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
961 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
962 					 long *s_num);
963 void mptcp_token_destroy(struct mptcp_sock *msk);
964 
965 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
966 
967 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
968 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
969 
970 void __init mptcp_pm_init(void);
971 void mptcp_pm_data_init(struct mptcp_sock *msk);
972 void mptcp_pm_data_reset(struct mptcp_sock *msk);
973 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
974 			struct mptcp_addr_info *addr);
975 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
976 			 bool require_family,
977 			 struct mptcp_pm_addr_entry *entry);
978 bool mptcp_pm_addr_families_match(const struct sock *sk,
979 				  const struct mptcp_addr_info *loc,
980 				  const struct mptcp_addr_info *rem);
981 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
982 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
983 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
984 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
985 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
986 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
987 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
988 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
989 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
990 				 const struct mptcp_subflow_context *subflow);
991 void mptcp_pm_add_addr_received(const struct sock *ssk,
992 				const struct mptcp_addr_info *addr);
993 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
994 			      const struct mptcp_addr_info *addr);
995 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
996 bool mptcp_pm_nl_is_init_remote_addr(struct mptcp_sock *msk,
997 				     const struct mptcp_addr_info *remote);
998 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
999 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
1000 			       const struct mptcp_rm_list *rm_list);
1001 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
1002 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
1003 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
1004 				 struct mptcp_addr_info *addr,
1005 				 struct mptcp_addr_info *rem,
1006 				 u8 bkup);
1007 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
1008 			      const struct mptcp_addr_info *addr);
1009 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
1010 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
1011 struct mptcp_pm_add_entry *
1012 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
1013 		       const struct mptcp_addr_info *addr, bool check_id);
1014 struct mptcp_pm_add_entry *
1015 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
1016 				const struct mptcp_addr_info *addr);
1017 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1018 					 unsigned int id,
1019 					 u8 *flags, int *ifindex);
1020 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
1021 					    u8 *flags, int *ifindex);
1022 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1023 						   unsigned int id,
1024 						   u8 *flags, int *ifindex);
1025 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1026 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
1027 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1028 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
1029 			   const struct mptcp_addr_info *addr,
1030 			   bool echo);
1031 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
1032 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
1033 
1034 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
1035 
1036 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
1037 		 const struct sock *ssk, gfp_t gfp);
1038 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
1039 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
1040 void mptcp_event_pm_listener(const struct sock *ssk,
1041 			     enum mptcp_event_type event);
1042 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
1043 
1044 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
1045 				     const struct mptcp_options_received *mp_opt);
1046 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
1047 					      struct request_sock *req);
1048 int mptcp_nl_fill_addr(struct sk_buff *skb,
1049 		       struct mptcp_pm_addr_entry *entry);
1050 
1051 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
1052 {
1053 	return READ_ONCE(msk->pm.addr_signal) &
1054 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
1055 }
1056 
1057 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
1058 {
1059 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
1060 }
1061 
1062 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
1063 {
1064 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
1065 }
1066 
1067 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
1068 {
1069 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
1070 }
1071 
1072 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1073 {
1074 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1075 }
1076 
1077 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1078 {
1079 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1080 }
1081 
1082 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1083 {
1084 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1085 
1086 	if (family == AF_INET6)
1087 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1088 	if (!echo)
1089 		len += MPTCPOPT_THMAC_LEN;
1090 	/* account for 2 trailing 'nop' options */
1091 	if (port)
1092 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1093 
1094 	return len;
1095 }
1096 
1097 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1098 {
1099 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1100 		return -EINVAL;
1101 
1102 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1103 }
1104 
1105 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1106 			      unsigned int opt_size, unsigned int remaining,
1107 			      struct mptcp_addr_info *addr, bool *echo,
1108 			      bool *drop_other_suboptions);
1109 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1110 			     struct mptcp_rm_list *rm_list);
1111 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1112 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1113 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1114 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
1115 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1116 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1117 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
1118 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1119 			  struct netlink_callback *cb);
1120 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
1121 				 struct netlink_callback *cb);
1122 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info);
1123 int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info);
1124 int mptcp_userspace_pm_get_addr(struct sk_buff *skb,
1125 				struct genl_info *info);
1126 
1127 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1128 {
1129 	int local_id = READ_ONCE(subflow->local_id);
1130 
1131 	if (local_id < 0)
1132 		return 0;
1133 	return local_id;
1134 }
1135 
1136 void __init mptcp_pm_nl_init(void);
1137 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1138 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1139 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1140 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1141 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1142 
1143 /* called under PM lock */
1144 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1145 {
1146 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1147 		WRITE_ONCE(msk->pm.accept_subflow, true);
1148 }
1149 
1150 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1151 {
1152 	spin_lock_bh(&msk->pm.lock);
1153 	__mptcp_pm_close_subflow(msk);
1154 	spin_unlock_bh(&msk->pm.lock);
1155 }
1156 
1157 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1158 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1159 
1160 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1161 {
1162 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1163 }
1164 
1165 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1166 
1167 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1168 {
1169 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1170 }
1171 
1172 static inline bool mptcp_check_fallback(const struct sock *sk)
1173 {
1174 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1175 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1176 
1177 	return __mptcp_check_fallback(msk);
1178 }
1179 
1180 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1181 {
1182 	if (__mptcp_check_fallback(msk)) {
1183 		pr_debug("TCP fallback already done (msk=%p)\n", msk);
1184 		return;
1185 	}
1186 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1187 }
1188 
1189 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1190 {
1191 	struct sock *ssk = READ_ONCE(msk->first);
1192 
1193 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1194 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1195 			TCPF_SYN_RECV | TCPF_LISTEN));
1196 }
1197 
1198 static inline void mptcp_do_fallback(struct sock *ssk)
1199 {
1200 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1201 	struct sock *sk = subflow->conn;
1202 	struct mptcp_sock *msk;
1203 
1204 	msk = mptcp_sk(sk);
1205 	__mptcp_do_fallback(msk);
1206 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1207 		gfp_t saved_allocation = ssk->sk_allocation;
1208 
1209 		/* we are in a atomic (BH) scope, override ssk default for data
1210 		 * fin allocation
1211 		 */
1212 		ssk->sk_allocation = GFP_ATOMIC;
1213 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1214 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1215 		ssk->sk_allocation = saved_allocation;
1216 	}
1217 }
1218 
1219 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)\n", __func__, a)
1220 
1221 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1222 {
1223 	struct mptcp_ext *mpext;
1224 
1225 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1226 	if (mpext && mpext->infinite_map)
1227 		return true;
1228 
1229 	return false;
1230 }
1231 
1232 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1233 {
1234 	return (subflow->request_mptcp || subflow->request_join);
1235 }
1236 
1237 static inline bool subflow_simultaneous_connect(struct sock *sk)
1238 {
1239 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1240 
1241 	return (1 << sk->sk_state) &
1242 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1243 	       is_active_ssk(subflow) &&
1244 	       !subflow->conn_finished;
1245 }
1246 
1247 #ifdef CONFIG_SYN_COOKIES
1248 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1249 				       struct sk_buff *skb);
1250 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1251 					struct sk_buff *skb);
1252 void __init mptcp_join_cookie_init(void);
1253 #else
1254 static inline void
1255 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1256 				  struct sk_buff *skb) {}
1257 static inline bool
1258 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1259 				   struct sk_buff *skb)
1260 {
1261 	return false;
1262 }
1263 
1264 static inline void mptcp_join_cookie_init(void) {}
1265 #endif
1266 
1267 #endif /* __MPTCP_PROTOCOL_H */
1268