xref: /linux/net/mptcp/protocol.h (revision 860a9bed265146b10311bcadbbcef59c3af4454d)
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 
16 #include "mptcp_pm_gen.h"
17 
18 #define MPTCP_SUPPORTED_VERSION	1
19 
20 /* MPTCP option bits */
21 #define OPTION_MPTCP_MPC_SYN	BIT(0)
22 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
23 #define OPTION_MPTCP_MPC_ACK	BIT(2)
24 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
25 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
26 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
27 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
28 #define OPTION_MPTCP_RM_ADDR	BIT(7)
29 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
30 #define OPTION_MPTCP_PRIO	BIT(9)
31 #define OPTION_MPTCP_RST	BIT(10)
32 #define OPTION_MPTCP_DSS	BIT(11)
33 #define OPTION_MPTCP_FAIL	BIT(12)
34 
35 #define OPTION_MPTCP_CSUMREQD	BIT(13)
36 
37 #define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
38 				 OPTION_MPTCP_MPC_ACK)
39 #define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
40 				 OPTION_MPTCP_MPJ_ACK)
41 
42 /* MPTCP option subtypes */
43 #define MPTCPOPT_MP_CAPABLE	0
44 #define MPTCPOPT_MP_JOIN	1
45 #define MPTCPOPT_DSS		2
46 #define MPTCPOPT_ADD_ADDR	3
47 #define MPTCPOPT_RM_ADDR	4
48 #define MPTCPOPT_MP_PRIO	5
49 #define MPTCPOPT_MP_FAIL	6
50 #define MPTCPOPT_MP_FASTCLOSE	7
51 #define MPTCPOPT_RST		8
52 
53 /* MPTCP suboption lengths */
54 #define TCPOLEN_MPTCP_MPC_SYN		4
55 #define TCPOLEN_MPTCP_MPC_SYNACK	12
56 #define TCPOLEN_MPTCP_MPC_ACK		20
57 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
58 #define TCPOLEN_MPTCP_MPJ_SYN		12
59 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
60 #define TCPOLEN_MPTCP_MPJ_ACK		24
61 #define TCPOLEN_MPTCP_DSS_BASE		4
62 #define TCPOLEN_MPTCP_DSS_ACK32		4
63 #define TCPOLEN_MPTCP_DSS_ACK64		8
64 #define TCPOLEN_MPTCP_DSS_MAP32		10
65 #define TCPOLEN_MPTCP_DSS_MAP64		14
66 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
67 #define TCPOLEN_MPTCP_ADD_ADDR		16
68 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
69 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
70 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
71 #define TCPOLEN_MPTCP_ADD_ADDR6		28
72 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
73 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
74 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
75 #define TCPOLEN_MPTCP_PORT_LEN		2
76 #define TCPOLEN_MPTCP_PORT_ALIGN	2
77 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
78 #define TCPOLEN_MPTCP_PRIO		3
79 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
80 #define TCPOLEN_MPTCP_FASTCLOSE		12
81 #define TCPOLEN_MPTCP_RST		4
82 #define TCPOLEN_MPTCP_FAIL		12
83 
84 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
85 
86 /* MPTCP MP_JOIN flags */
87 #define MPTCPOPT_BACKUP		BIT(0)
88 #define MPTCPOPT_THMAC_LEN	8
89 
90 /* MPTCP MP_CAPABLE flags */
91 #define MPTCP_VERSION_MASK	(0x0F)
92 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
93 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
94 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
95 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
96 #define MPTCP_CAP_FLAG_MASK	(0x1F)
97 
98 /* MPTCP DSS flags */
99 #define MPTCP_DSS_DATA_FIN	BIT(4)
100 #define MPTCP_DSS_DSN64		BIT(3)
101 #define MPTCP_DSS_HAS_MAP	BIT(2)
102 #define MPTCP_DSS_ACK64		BIT(1)
103 #define MPTCP_DSS_HAS_ACK	BIT(0)
104 #define MPTCP_DSS_FLAG_MASK	(0x1F)
105 
106 /* MPTCP ADD_ADDR flags */
107 #define MPTCP_ADDR_ECHO		BIT(0)
108 
109 /* MPTCP MP_PRIO flags */
110 #define MPTCP_PRIO_BKUP		BIT(0)
111 
112 /* MPTCP TCPRST flags */
113 #define MPTCP_RST_TRANSIENT	BIT(0)
114 
115 /* MPTCP socket atomic flags */
116 #define MPTCP_WORK_RTX		1
117 #define MPTCP_FALLBACK_DONE	2
118 #define MPTCP_WORK_CLOSE_SUBFLOW 3
119 
120 /* MPTCP socket release cb flags */
121 #define MPTCP_PUSH_PENDING	1
122 #define MPTCP_CLEAN_UNA		2
123 #define MPTCP_ERROR_REPORT	3
124 #define MPTCP_RETRANSMIT	4
125 #define MPTCP_FLUSH_JOIN_LIST	5
126 #define MPTCP_SYNC_STATE	6
127 #define MPTCP_SYNC_SNDBUF	7
128 
129 struct mptcp_skb_cb {
130 	u64 map_seq;
131 	u64 end_seq;
132 	u32 offset;
133 	u8  has_rxtstamp:1;
134 };
135 
136 #define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
137 
138 static inline bool before64(__u64 seq1, __u64 seq2)
139 {
140 	return (__s64)(seq1 - seq2) < 0;
141 }
142 
143 #define after64(seq2, seq1)	before64(seq1, seq2)
144 
145 struct mptcp_options_received {
146 	u64	sndr_key;
147 	u64	rcvr_key;
148 	u64	data_ack;
149 	u64	data_seq;
150 	u32	subflow_seq;
151 	u16	data_len;
152 	__sum16	csum;
153 	u16	suboptions;
154 	u32	token;
155 	u32	nonce;
156 	u16	use_map:1,
157 		dsn64:1,
158 		data_fin:1,
159 		use_ack:1,
160 		ack64:1,
161 		mpc_map:1,
162 		reset_reason:4,
163 		reset_transient:1,
164 		echo:1,
165 		backup:1,
166 		deny_join_id0:1,
167 		__unused:2;
168 	u8	join_id;
169 	u64	thmac;
170 	u8	hmac[MPTCPOPT_HMAC_LEN];
171 	struct mptcp_addr_info addr;
172 	struct mptcp_rm_list rm_list;
173 	u64	ahmac;
174 	u64	fail_seq;
175 };
176 
177 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
178 {
179 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
180 		     ((nib & 0xF) << 8) | field);
181 }
182 
183 enum mptcp_pm_status {
184 	MPTCP_PM_ADD_ADDR_RECEIVED,
185 	MPTCP_PM_ADD_ADDR_SEND_ACK,
186 	MPTCP_PM_RM_ADDR_RECEIVED,
187 	MPTCP_PM_ESTABLISHED,
188 	MPTCP_PM_SUBFLOW_ESTABLISHED,
189 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
190 	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
191 					 * accounted int id_avail_bitmap
192 					 */
193 };
194 
195 enum mptcp_pm_type {
196 	MPTCP_PM_TYPE_KERNEL = 0,
197 	MPTCP_PM_TYPE_USERSPACE,
198 
199 	__MPTCP_PM_TYPE_NR,
200 	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
201 };
202 
203 /* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */
204 #define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)
205 
206 enum mptcp_addr_signal_status {
207 	MPTCP_ADD_ADDR_SIGNAL,
208 	MPTCP_ADD_ADDR_ECHO,
209 	MPTCP_RM_ADDR_SIGNAL,
210 };
211 
212 /* max value of mptcp_addr_info.id */
213 #define MPTCP_PM_MAX_ADDR_ID		U8_MAX
214 
215 struct mptcp_pm_data {
216 	struct mptcp_addr_info local;
217 	struct mptcp_addr_info remote;
218 	struct list_head anno_list;
219 	struct list_head userspace_pm_local_addr_list;
220 
221 	spinlock_t	lock;		/*protects the whole PM data */
222 
223 	u8		addr_signal;
224 	bool		server_side;
225 	bool		work_pending;
226 	bool		accept_addr;
227 	bool		accept_subflow;
228 	bool		remote_deny_join_id0;
229 	u8		add_addr_signaled;
230 	u8		add_addr_accepted;
231 	u8		local_addr_used;
232 	u8		pm_type;
233 	u8		subflows;
234 	u8		status;
235 	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
236 	struct mptcp_rm_list rm_list_tx;
237 	struct mptcp_rm_list rm_list_rx;
238 };
239 
240 struct mptcp_pm_addr_entry {
241 	struct list_head	list;
242 	struct mptcp_addr_info	addr;
243 	u8			flags;
244 	int			ifindex;
245 	struct socket		*lsk;
246 };
247 
248 struct mptcp_data_frag {
249 	struct list_head list;
250 	u64 data_seq;
251 	u16 data_len;
252 	u16 offset;
253 	u16 overhead;
254 	u16 already_sent;
255 	struct page *page;
256 };
257 
258 /* MPTCP connection sock */
259 struct mptcp_sock {
260 	/* inet_connection_sock must be the first member */
261 	struct inet_connection_sock sk;
262 	u64		local_key;		/* protected by the first subflow socket lock
263 						 * lockless access read
264 						 */
265 	u64		remote_key;		/* same as above */
266 	u64		write_seq;
267 	u64		bytes_sent;
268 	u64		snd_nxt;
269 	u64		bytes_received;
270 	u64		ack_seq;
271 	atomic64_t	rcv_wnd_sent;
272 	u64		rcv_data_fin_seq;
273 	u64		bytes_retrans;
274 	u64		bytes_consumed;
275 	int		rmem_fwd_alloc;
276 	int		snd_burst;
277 	int		old_wspace;
278 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
279 						 * recovery related fields are under data_lock
280 						 * protection
281 						 */
282 	u64		bytes_acked;
283 	u64		snd_una;
284 	u64		wnd_end;
285 	u32		last_data_sent;
286 	u32		last_data_recv;
287 	u32		last_ack_recv;
288 	unsigned long	timer_ival;
289 	u32		token;
290 	int		rmem_released;
291 	unsigned long	flags;
292 	unsigned long	cb_flags;
293 	bool		recovery;		/* closing subflow write queue reinjected */
294 	bool		can_ack;
295 	bool		fully_established;
296 	bool		rcv_data_fin;
297 	bool		snd_data_fin_enable;
298 	bool		rcv_fastclose;
299 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
300 	bool		csum_enabled;
301 	bool		allow_infinite_fallback;
302 	u8		pending_state; /* A subflow asked to set this sk_state,
303 					* protected by the msk data lock
304 					*/
305 	u8		mpc_endpoint_id;
306 	u8		recvmsg_inq:1,
307 			cork:1,
308 			nodelay:1,
309 			fastopening:1,
310 			in_accept_queue:1,
311 			free_first:1,
312 			rcvspace_init:1;
313 	u32		notsent_lowat;
314 	struct work_struct work;
315 	struct sk_buff  *ooo_last_skb;
316 	struct rb_root  out_of_order_queue;
317 	struct sk_buff_head receive_queue;
318 	struct list_head conn_list;
319 	struct list_head rtx_queue;
320 	struct mptcp_data_frag *first_pending;
321 	struct list_head join_list;
322 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
323 				 * ONCE annotation, the subflow outside the socket
324 				 * lock as such sock is freed after close().
325 				 */
326 	struct mptcp_pm_data	pm;
327 	struct mptcp_sched_ops	*sched;
328 	struct {
329 		u32	space;	/* bytes copied in last measurement window */
330 		u32	copied; /* bytes copied in this measurement window */
331 		u64	time;	/* start time of measurement window */
332 		u64	rtt_us; /* last maximum rtt of subflows */
333 	} rcvq_space;
334 	u8		scaling_ratio;
335 
336 	u32		subflow_id;
337 	u32		setsockopt_seq;
338 	char		ca_name[TCP_CA_NAME_MAX];
339 };
340 
341 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
342 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
343 
344 #define mptcp_for_each_subflow(__msk, __subflow)			\
345 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
346 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
347 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
348 
349 extern struct genl_family mptcp_genl_family;
350 
351 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
352 {
353 	sock_owned_by_me((const struct sock *)msk);
354 }
355 
356 #ifdef CONFIG_DEBUG_NET
357 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
358 #undef tcp_sk
359 #define tcp_sk(ptr) ({								\
360 	typeof(ptr) _ptr = (ptr);						\
361 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
362 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
363 })
364 #define mptcp_sk(ptr) ({						\
365 	typeof(ptr) _ptr = (ptr);					\
366 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
367 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
368 })
369 
370 #else /* !CONFIG_DEBUG_NET */
371 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
372 #endif
373 
374 /* the msk socket don't use the backlog, also account for the bulk
375  * free memory
376  */
377 static inline int __mptcp_rmem(const struct sock *sk)
378 {
379 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
380 }
381 
382 static inline int mptcp_win_from_space(const struct sock *sk, int space)
383 {
384 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
385 }
386 
387 static inline int __mptcp_space(const struct sock *sk)
388 {
389 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
390 }
391 
392 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
393 {
394 	const struct mptcp_sock *msk = mptcp_sk(sk);
395 
396 	return READ_ONCE(msk->first_pending);
397 }
398 
399 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
400 {
401 	struct mptcp_sock *msk = mptcp_sk(sk);
402 	struct mptcp_data_frag *cur;
403 
404 	cur = msk->first_pending;
405 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
406 						     list_next_entry(cur, list);
407 }
408 
409 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
410 {
411 	const struct mptcp_sock *msk = mptcp_sk(sk);
412 
413 	if (!msk->first_pending)
414 		return NULL;
415 
416 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
417 		return NULL;
418 
419 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
420 }
421 
422 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
423 {
424 	struct mptcp_sock *msk = mptcp_sk(sk);
425 
426 	if (msk->snd_una == msk->snd_nxt)
427 		return NULL;
428 
429 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
430 }
431 
432 struct csum_pseudo_header {
433 	__be64 data_seq;
434 	__be32 subflow_seq;
435 	__be16 data_len;
436 	__sum16 csum;
437 };
438 
439 struct mptcp_subflow_request_sock {
440 	struct	tcp_request_sock sk;
441 	u16	mp_capable : 1,
442 		mp_join : 1,
443 		backup : 1,
444 		csum_reqd : 1,
445 		allow_join_id0 : 1;
446 	u8	local_id;
447 	u8	remote_id;
448 	u64	local_key;
449 	u64	idsn;
450 	u32	token;
451 	u32	ssn_offset;
452 	u64	thmac;
453 	u32	local_nonce;
454 	u32	remote_nonce;
455 	struct mptcp_sock	*msk;
456 	struct hlist_nulls_node token_node;
457 };
458 
459 static inline struct mptcp_subflow_request_sock *
460 mptcp_subflow_rsk(const struct request_sock *rsk)
461 {
462 	return (struct mptcp_subflow_request_sock *)rsk;
463 }
464 
465 struct mptcp_delegated_action {
466 	struct napi_struct napi;
467 	struct list_head head;
468 };
469 
470 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
471 
472 #define MPTCP_DELEGATE_SCHEDULED	0
473 #define MPTCP_DELEGATE_SEND		1
474 #define MPTCP_DELEGATE_ACK		2
475 #define MPTCP_DELEGATE_SNDBUF		3
476 
477 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
478 /* MPTCP subflow context */
479 struct mptcp_subflow_context {
480 	struct	list_head node;/* conn_list of subflows */
481 
482 	struct_group(reset,
483 
484 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
485 	u64	local_key;
486 	u64	remote_key;
487 	u64	idsn;
488 	u64	map_seq;
489 	u32	snd_isn;
490 	u32	token;
491 	u32	rel_write_seq;
492 	u32	map_subflow_seq;
493 	u32	ssn_offset;
494 	u32	map_data_len;
495 	__wsum	map_data_csum;
496 	u32	map_csum_len;
497 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
498 		request_join : 1,   /* send MP_JOIN */
499 		request_bkup : 1,
500 		mp_capable : 1,	    /* remote is MPTCP capable */
501 		mp_join : 1,	    /* remote is JOINing */
502 		fully_established : 1,	    /* path validated */
503 		pm_notified : 1,    /* PM hook called for established status */
504 		conn_finished : 1,
505 		map_valid : 1,
506 		map_csum_reqd : 1,
507 		map_data_fin : 1,
508 		mpc_map : 1,
509 		backup : 1,
510 		send_mp_prio : 1,
511 		send_mp_fail : 1,
512 		send_fastclose : 1,
513 		send_infinite_map : 1,
514 		remote_key_valid : 1,        /* received the peer key from */
515 		disposable : 1,	    /* ctx can be free at ulp release time */
516 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
517 		valid_csum_seen : 1,        /* at least one csum validated */
518 		is_mptfo : 1,	    /* subflow is doing TFO */
519 		__unused : 10;
520 	bool	data_avail;
521 	bool	scheduled;
522 	u32	remote_nonce;
523 	u64	thmac;
524 	u32	local_nonce;
525 	u32	remote_token;
526 	union {
527 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
528 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
529 	};
530 	s16	local_id;	    /* if negative not initialized yet */
531 	u8	remote_id;
532 	u8	reset_seen:1;
533 	u8	reset_transient:1;
534 	u8	reset_reason:4;
535 	u8	stale_count;
536 
537 	u32	subflow_id;
538 
539 	long	delegated_status;
540 	unsigned long	fail_tout;
541 
542 	);
543 
544 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
545 
546 	u32	setsockopt_seq;
547 	u32	stale_rcv_tstamp;
548 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
549 				     * protected by the msk socket lock
550 				     */
551 
552 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
553 	struct	sock *conn;	    /* parent mptcp_sock */
554 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
555 	void	(*tcp_state_change)(struct sock *sk);
556 	void	(*tcp_error_report)(struct sock *sk);
557 
558 	struct	rcu_head rcu;
559 };
560 
561 static inline struct mptcp_subflow_context *
562 mptcp_subflow_ctx(const struct sock *sk)
563 {
564 	const struct inet_connection_sock *icsk = inet_csk(sk);
565 
566 	/* Use RCU on icsk_ulp_data only for sock diag code */
567 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
568 }
569 
570 static inline struct sock *
571 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
572 {
573 	return subflow->tcp_sock;
574 }
575 
576 static inline void
577 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
578 {
579 	memset(&subflow->reset, 0, sizeof(subflow->reset));
580 	subflow->request_mptcp = 1;
581 	WRITE_ONCE(subflow->local_id, -1);
582 }
583 
584 static inline u64
585 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
586 {
587 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
588 		      subflow->ssn_offset -
589 		      subflow->map_subflow_seq;
590 }
591 
592 static inline u64
593 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
594 {
595 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
596 }
597 
598 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
599 
600 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
601 {
602 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
603 	struct mptcp_delegated_action *delegated;
604 	bool schedule;
605 
606 	/* the caller held the subflow bh socket lock */
607 	lockdep_assert_in_softirq();
608 
609 	/* The implied barrier pairs with tcp_release_cb_override()
610 	 * mptcp_napi_poll(), and ensures the below list check sees list
611 	 * updates done prior to delegated status bits changes
612 	 */
613 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
614 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
615 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
616 			return;
617 
618 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
619 		schedule = list_empty(&delegated->head);
620 		list_add_tail(&subflow->delegated_node, &delegated->head);
621 		sock_hold(mptcp_subflow_tcp_sock(subflow));
622 		if (schedule)
623 			napi_schedule(&delegated->napi);
624 	}
625 }
626 
627 static inline struct mptcp_subflow_context *
628 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
629 {
630 	struct mptcp_subflow_context *ret;
631 
632 	if (list_empty(&delegated->head))
633 		return NULL;
634 
635 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
636 	list_del_init(&ret->delegated_node);
637 	return ret;
638 }
639 
640 int mptcp_is_enabled(const struct net *net);
641 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
642 int mptcp_is_checksum_enabled(const struct net *net);
643 int mptcp_allow_join_id0(const struct net *net);
644 unsigned int mptcp_stale_loss_cnt(const struct net *net);
645 unsigned int mptcp_close_timeout(const struct sock *sk);
646 int mptcp_get_pm_type(const struct net *net);
647 const char *mptcp_get_scheduler(const struct net *net);
648 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
649 				       struct mptcp_subflow_context *subflow,
650 				       const struct mptcp_options_received *mp_opt);
651 bool __mptcp_retransmit_pending_data(struct sock *sk);
652 void mptcp_check_and_set_pending(struct sock *sk);
653 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
654 bool mptcp_subflow_data_available(struct sock *sk);
655 void __init mptcp_subflow_init(void);
656 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
657 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
658 		     struct mptcp_subflow_context *subflow);
659 void __mptcp_subflow_send_ack(struct sock *ssk);
660 void mptcp_subflow_reset(struct sock *ssk);
661 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
662 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
663 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
664 bool __mptcp_close(struct sock *sk, long timeout);
665 void mptcp_cancel_work(struct sock *sk);
666 void __mptcp_unaccepted_force_close(struct sock *sk);
667 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
668 void mptcp_set_state(struct sock *sk, int state);
669 
670 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
671 			   const struct mptcp_addr_info *b, bool use_port);
672 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
673 
674 /* called with sk socket lock held */
675 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
676 			    const struct mptcp_addr_info *remote);
677 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
678 				struct socket **new_sock);
679 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
680 			 struct sockaddr_storage *addr,
681 			 unsigned short family);
682 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
683 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
684 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
685 void mptcp_sched_init(void);
686 int mptcp_init_sched(struct mptcp_sock *msk,
687 		     struct mptcp_sched_ops *sched);
688 void mptcp_release_sched(struct mptcp_sock *msk);
689 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
690 				 bool scheduled);
691 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
692 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
693 int mptcp_sched_get_send(struct mptcp_sock *msk);
694 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
695 
696 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
697 {
698 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
699 }
700 
701 static inline bool mptcp_epollin_ready(const struct sock *sk)
702 {
703 	/* mptcp doesn't have to deal with small skbs in the receive queue,
704 	 * at it can always coalesce them
705 	 */
706 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
707 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
708 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
709 	       READ_ONCE(tcp_memory_pressure);
710 }
711 
712 int mptcp_set_rcvlowat(struct sock *sk, int val);
713 
714 static inline bool __tcp_can_send(const struct sock *ssk)
715 {
716 	/* only send if our side has not closed yet */
717 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
718 }
719 
720 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
721 {
722 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
723 	if (subflow->request_join && !subflow->fully_established)
724 		return false;
725 
726 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
727 }
728 
729 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
730 
731 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
732 
733 void mptcp_subflow_drop_ctx(struct sock *ssk);
734 
735 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
736 					      struct mptcp_subflow_context *ctx)
737 {
738 	sk->sk_data_ready = sock_def_readable;
739 	sk->sk_state_change = ctx->tcp_state_change;
740 	sk->sk_write_space = sk_stream_write_space;
741 	sk->sk_error_report = ctx->tcp_error_report;
742 
743 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
744 }
745 
746 void __init mptcp_proto_init(void);
747 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
748 int __init mptcp_proto_v6_init(void);
749 #endif
750 
751 struct sock *mptcp_sk_clone_init(const struct sock *sk,
752 				 const struct mptcp_options_received *mp_opt,
753 				 struct sock *ssk,
754 				 struct request_sock *req);
755 void mptcp_get_options(const struct sk_buff *skb,
756 		       struct mptcp_options_received *mp_opt);
757 
758 void mptcp_finish_connect(struct sock *sk);
759 void __mptcp_sync_state(struct sock *sk, int state);
760 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
761 
762 static inline void mptcp_stop_tout_timer(struct sock *sk)
763 {
764 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
765 		return;
766 
767 	sk_stop_timer(sk, &sk->sk_timer);
768 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
769 }
770 
771 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
772 {
773 	/* avoid 0 timestamp, as that means no close timeout */
774 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
775 }
776 
777 static inline void mptcp_start_tout_timer(struct sock *sk)
778 {
779 	mptcp_set_close_tout(sk, tcp_jiffies32);
780 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
781 }
782 
783 static inline bool mptcp_is_fully_established(struct sock *sk)
784 {
785 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
786 	       READ_ONCE(mptcp_sk(sk)->fully_established);
787 }
788 
789 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
790 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
791 bool mptcp_finish_join(struct sock *sk);
792 bool mptcp_schedule_work(struct sock *sk);
793 int mptcp_setsockopt(struct sock *sk, int level, int optname,
794 		     sockptr_t optval, unsigned int optlen);
795 int mptcp_getsockopt(struct sock *sk, int level, int optname,
796 		     char __user *optval, int __user *option);
797 
798 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
799 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
800 {
801 	if (use_64bit)
802 		return cur_seq;
803 
804 	return __mptcp_expand_seq(old_seq, cur_seq);
805 }
806 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
807 void __mptcp_data_acked(struct sock *sk);
808 void __mptcp_error_report(struct sock *sk);
809 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
810 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
811 {
812 	return READ_ONCE(msk->snd_data_fin_enable) &&
813 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
814 }
815 
816 static inline u32 mptcp_notsent_lowat(const struct sock *sk)
817 {
818 	struct net *net = sock_net(sk);
819 	u32 val;
820 
821 	val = READ_ONCE(mptcp_sk(sk)->notsent_lowat);
822 	return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
823 }
824 
825 static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake)
826 {
827 	const struct mptcp_sock *msk = mptcp_sk(sk);
828 	u32 notsent_bytes;
829 
830 	notsent_bytes = READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt);
831 	return (notsent_bytes << wake) < mptcp_notsent_lowat(sk);
832 }
833 
834 static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake)
835 {
836 	return mptcp_stream_memory_free(sk, wake) &&
837 	       __sk_stream_is_writeable(sk, wake);
838 }
839 
840 static inline void mptcp_write_space(struct sock *sk)
841 {
842 	/* pairs with memory barrier in mptcp_poll */
843 	smp_mb();
844 	if (mptcp_stream_memory_free(sk, 1))
845 		sk_stream_write_space(sk);
846 }
847 
848 static inline void __mptcp_sync_sndbuf(struct sock *sk)
849 {
850 	struct mptcp_subflow_context *subflow;
851 	int ssk_sndbuf, new_sndbuf;
852 
853 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
854 		return;
855 
856 	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
857 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
858 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
859 
860 		subflow->cached_sndbuf = ssk_sndbuf;
861 		new_sndbuf += ssk_sndbuf;
862 	}
863 
864 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
865 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
866 	mptcp_write_space(sk);
867 }
868 
869 /* The called held both the msk socket and the subflow socket locks,
870  * possibly under BH
871  */
872 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
873 {
874 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
875 
876 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
877 		__mptcp_sync_sndbuf(sk);
878 }
879 
880 /* the caller held only the subflow socket lock, either in process or
881  * BH context. Additionally this can be called under the msk data lock,
882  * so we can't acquire such lock here: let the delegate action acquires
883  * the needed locks in suitable order.
884  */
885 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
886 {
887 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
888 
889 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
890 		return;
891 
892 	local_bh_disable();
893 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
894 	local_bh_enable();
895 }
896 
897 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
898 
899 #define MPTCP_TOKEN_MAX_RETRIES	4
900 
901 void __init mptcp_token_init(void);
902 static inline void mptcp_token_init_request(struct request_sock *req)
903 {
904 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
905 }
906 
907 int mptcp_token_new_request(struct request_sock *req);
908 void mptcp_token_destroy_request(struct request_sock *req);
909 int mptcp_token_new_connect(struct sock *ssk);
910 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
911 			struct mptcp_sock *msk);
912 bool mptcp_token_exists(u32 token);
913 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
914 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
915 					 long *s_num);
916 void mptcp_token_destroy(struct mptcp_sock *msk);
917 
918 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
919 
920 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
921 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
922 
923 void __init mptcp_pm_init(void);
924 void mptcp_pm_data_init(struct mptcp_sock *msk);
925 void mptcp_pm_data_reset(struct mptcp_sock *msk);
926 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
927 			struct mptcp_addr_info *addr);
928 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
929 			 bool require_family,
930 			 struct mptcp_pm_addr_entry *entry);
931 bool mptcp_pm_addr_families_match(const struct sock *sk,
932 				  const struct mptcp_addr_info *loc,
933 				  const struct mptcp_addr_info *rem);
934 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
935 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
936 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
937 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
938 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
939 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
940 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
941 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
942 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
943 				 const struct mptcp_subflow_context *subflow);
944 void mptcp_pm_add_addr_received(const struct sock *ssk,
945 				const struct mptcp_addr_info *addr);
946 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
947 			      const struct mptcp_addr_info *addr);
948 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
949 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
950 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
951 			       const struct mptcp_rm_list *rm_list);
952 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
953 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
954 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
955 				 struct mptcp_addr_info *addr,
956 				 struct mptcp_addr_info *rem,
957 				 u8 bkup);
958 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
959 			      const struct mptcp_addr_info *addr);
960 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
961 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
962 struct mptcp_pm_add_entry *
963 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
964 		       const struct mptcp_addr_info *addr, bool check_id);
965 struct mptcp_pm_add_entry *
966 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
967 				const struct mptcp_addr_info *addr);
968 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
969 					 unsigned int id,
970 					 u8 *flags, int *ifindex);
971 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
972 					    u8 *flags, int *ifindex);
973 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
974 						   unsigned int id,
975 						   u8 *flags, int *ifindex);
976 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
977 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
978 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
979 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
980 			   const struct mptcp_addr_info *addr,
981 			   bool echo);
982 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
983 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
984 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
985 
986 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
987 
988 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
989 		 const struct sock *ssk, gfp_t gfp);
990 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
991 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
992 void mptcp_event_pm_listener(const struct sock *ssk,
993 			     enum mptcp_event_type event);
994 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
995 
996 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
997 				     const struct mptcp_options_received *mp_opt);
998 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
999 					      struct request_sock *req);
1000 int mptcp_nl_fill_addr(struct sk_buff *skb,
1001 		       struct mptcp_pm_addr_entry *entry);
1002 
1003 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
1004 {
1005 	return READ_ONCE(msk->pm.addr_signal) &
1006 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
1007 }
1008 
1009 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
1010 {
1011 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
1012 }
1013 
1014 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
1015 {
1016 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
1017 }
1018 
1019 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
1020 {
1021 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
1022 }
1023 
1024 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1025 {
1026 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1027 }
1028 
1029 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1030 {
1031 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1032 }
1033 
1034 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1035 {
1036 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1037 
1038 	if (family == AF_INET6)
1039 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1040 	if (!echo)
1041 		len += MPTCPOPT_THMAC_LEN;
1042 	/* account for 2 trailing 'nop' options */
1043 	if (port)
1044 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1045 
1046 	return len;
1047 }
1048 
1049 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1050 {
1051 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1052 		return -EINVAL;
1053 
1054 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1055 }
1056 
1057 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1058 			      unsigned int opt_size, unsigned int remaining,
1059 			      struct mptcp_addr_info *addr, bool *echo,
1060 			      bool *drop_other_suboptions);
1061 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1062 			     struct mptcp_rm_list *rm_list);
1063 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1064 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1065 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1066 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
1067 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1068 			  struct netlink_callback *cb);
1069 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
1070 				 struct netlink_callback *cb);
1071 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info);
1072 int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info);
1073 int mptcp_userspace_pm_get_addr(struct sk_buff *skb,
1074 				struct genl_info *info);
1075 
1076 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1077 {
1078 	int local_id = READ_ONCE(subflow->local_id);
1079 
1080 	if (local_id < 0)
1081 		return 0;
1082 	return local_id;
1083 }
1084 
1085 void __init mptcp_pm_nl_init(void);
1086 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1087 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1088 				     const struct mptcp_rm_list *rm_list);
1089 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1090 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1091 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1092 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1093 
1094 /* called under PM lock */
1095 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1096 {
1097 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1098 		WRITE_ONCE(msk->pm.accept_subflow, true);
1099 }
1100 
1101 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1102 {
1103 	spin_lock_bh(&msk->pm.lock);
1104 	__mptcp_pm_close_subflow(msk);
1105 	spin_unlock_bh(&msk->pm.lock);
1106 }
1107 
1108 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1109 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1110 
1111 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1112 {
1113 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1114 }
1115 
1116 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1117 
1118 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1119 {
1120 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1121 }
1122 
1123 static inline bool mptcp_check_fallback(const struct sock *sk)
1124 {
1125 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1126 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1127 
1128 	return __mptcp_check_fallback(msk);
1129 }
1130 
1131 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1132 {
1133 	if (__mptcp_check_fallback(msk)) {
1134 		pr_debug("TCP fallback already done (msk=%p)", msk);
1135 		return;
1136 	}
1137 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1138 }
1139 
1140 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1141 {
1142 	struct sock *ssk = READ_ONCE(msk->first);
1143 
1144 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1145 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1146 			TCPF_SYN_RECV | TCPF_LISTEN));
1147 }
1148 
1149 static inline void mptcp_do_fallback(struct sock *ssk)
1150 {
1151 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1152 	struct sock *sk = subflow->conn;
1153 	struct mptcp_sock *msk;
1154 
1155 	msk = mptcp_sk(sk);
1156 	__mptcp_do_fallback(msk);
1157 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1158 		gfp_t saved_allocation = ssk->sk_allocation;
1159 
1160 		/* we are in a atomic (BH) scope, override ssk default for data
1161 		 * fin allocation
1162 		 */
1163 		ssk->sk_allocation = GFP_ATOMIC;
1164 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1165 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1166 		ssk->sk_allocation = saved_allocation;
1167 	}
1168 }
1169 
1170 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1171 
1172 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1173 {
1174 	struct mptcp_ext *mpext;
1175 
1176 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1177 	if (mpext && mpext->infinite_map)
1178 		return true;
1179 
1180 	return false;
1181 }
1182 
1183 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1184 {
1185 	return (subflow->request_mptcp || subflow->request_join);
1186 }
1187 
1188 static inline bool subflow_simultaneous_connect(struct sock *sk)
1189 {
1190 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1191 
1192 	return (1 << sk->sk_state) &
1193 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1194 	       is_active_ssk(subflow) &&
1195 	       !subflow->conn_finished;
1196 }
1197 
1198 #ifdef CONFIG_SYN_COOKIES
1199 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1200 				       struct sk_buff *skb);
1201 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1202 					struct sk_buff *skb);
1203 void __init mptcp_join_cookie_init(void);
1204 #else
1205 static inline void
1206 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1207 				  struct sk_buff *skb) {}
1208 static inline bool
1209 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1210 				   struct sk_buff *skb)
1211 {
1212 	return false;
1213 }
1214 
1215 static inline void mptcp_join_cookie_init(void) {}
1216 #endif
1217 
1218 #endif /* __MPTCP_PROTOCOL_H */
1219