xref: /openbmc/linux/net/mptcp/protocol.h (revision cca20208)
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 #define MPTCP_SUPPORTED_VERSION	1
17 
18 /* MPTCP option bits */
19 #define OPTION_MPTCP_MPC_SYN	BIT(0)
20 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
21 #define OPTION_MPTCP_MPC_ACK	BIT(2)
22 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
23 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
24 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
25 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
26 #define OPTION_MPTCP_RM_ADDR	BIT(7)
27 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
28 #define OPTION_MPTCP_PRIO	BIT(9)
29 #define OPTION_MPTCP_RST	BIT(10)
30 #define OPTION_MPTCP_DSS	BIT(11)
31 #define OPTION_MPTCP_FAIL	BIT(12)
32 
33 #define OPTION_MPTCP_CSUMREQD	BIT(13)
34 
35 #define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
36 				 OPTION_MPTCP_MPC_ACK)
37 #define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
38 				 OPTION_MPTCP_MPJ_ACK)
39 
40 /* MPTCP option subtypes */
41 #define MPTCPOPT_MP_CAPABLE	0
42 #define MPTCPOPT_MP_JOIN	1
43 #define MPTCPOPT_DSS		2
44 #define MPTCPOPT_ADD_ADDR	3
45 #define MPTCPOPT_RM_ADDR	4
46 #define MPTCPOPT_MP_PRIO	5
47 #define MPTCPOPT_MP_FAIL	6
48 #define MPTCPOPT_MP_FASTCLOSE	7
49 #define MPTCPOPT_RST		8
50 
51 /* MPTCP suboption lengths */
52 #define TCPOLEN_MPTCP_MPC_SYN		4
53 #define TCPOLEN_MPTCP_MPC_SYNACK	12
54 #define TCPOLEN_MPTCP_MPC_ACK		20
55 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
56 #define TCPOLEN_MPTCP_MPJ_SYN		12
57 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
58 #define TCPOLEN_MPTCP_MPJ_ACK		24
59 #define TCPOLEN_MPTCP_DSS_BASE		4
60 #define TCPOLEN_MPTCP_DSS_ACK32		4
61 #define TCPOLEN_MPTCP_DSS_ACK64		8
62 #define TCPOLEN_MPTCP_DSS_MAP32		10
63 #define TCPOLEN_MPTCP_DSS_MAP64		14
64 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
65 #define TCPOLEN_MPTCP_ADD_ADDR		16
66 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
67 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
68 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
69 #define TCPOLEN_MPTCP_ADD_ADDR6		28
70 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
71 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
72 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
73 #define TCPOLEN_MPTCP_PORT_LEN		2
74 #define TCPOLEN_MPTCP_PORT_ALIGN	2
75 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
76 #define TCPOLEN_MPTCP_PRIO		3
77 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
78 #define TCPOLEN_MPTCP_FASTCLOSE		12
79 #define TCPOLEN_MPTCP_RST		4
80 #define TCPOLEN_MPTCP_FAIL		12
81 
82 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
83 
84 /* MPTCP MP_JOIN flags */
85 #define MPTCPOPT_BACKUP		BIT(0)
86 #define MPTCPOPT_THMAC_LEN	8
87 
88 /* MPTCP MP_CAPABLE flags */
89 #define MPTCP_VERSION_MASK	(0x0F)
90 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
91 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
92 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
93 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
94 #define MPTCP_CAP_FLAG_MASK	(0x1F)
95 
96 /* MPTCP DSS flags */
97 #define MPTCP_DSS_DATA_FIN	BIT(4)
98 #define MPTCP_DSS_DSN64		BIT(3)
99 #define MPTCP_DSS_HAS_MAP	BIT(2)
100 #define MPTCP_DSS_ACK64		BIT(1)
101 #define MPTCP_DSS_HAS_ACK	BIT(0)
102 #define MPTCP_DSS_FLAG_MASK	(0x1F)
103 
104 /* MPTCP ADD_ADDR flags */
105 #define MPTCP_ADDR_ECHO		BIT(0)
106 
107 /* MPTCP MP_PRIO flags */
108 #define MPTCP_PRIO_BKUP		BIT(0)
109 
110 /* MPTCP TCPRST flags */
111 #define MPTCP_RST_TRANSIENT	BIT(0)
112 
113 /* MPTCP socket atomic flags */
114 #define MPTCP_NOSPACE		1
115 #define MPTCP_WORK_RTX		2
116 #define MPTCP_FALLBACK_DONE	4
117 #define MPTCP_WORK_CLOSE_SUBFLOW 5
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;
262 	u64		remote_key;
263 	u64		write_seq;
264 	u64		bytes_sent;
265 	u64		snd_nxt;
266 	u64		bytes_received;
267 	u64		ack_seq;
268 	atomic64_t	rcv_wnd_sent;
269 	u64		rcv_data_fin_seq;
270 	u64		bytes_retrans;
271 	int		rmem_fwd_alloc;
272 	int		snd_burst;
273 	int		old_wspace;
274 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
275 						 * recovery related fields are under data_lock
276 						 * protection
277 						 */
278 	u64		bytes_acked;
279 	u64		snd_una;
280 	u64		wnd_end;
281 	unsigned long	timer_ival;
282 	u32		token;
283 	int		rmem_released;
284 	unsigned long	flags;
285 	unsigned long	cb_flags;
286 	bool		recovery;		/* closing subflow write queue reinjected */
287 	bool		can_ack;
288 	bool		fully_established;
289 	bool		rcv_data_fin;
290 	bool		snd_data_fin_enable;
291 	bool		rcv_fastclose;
292 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
293 	bool		csum_enabled;
294 	bool		allow_infinite_fallback;
295 	u8		pending_state; /* A subflow asked to set this sk_state,
296 					* protected by the msk data lock
297 					*/
298 	u8		mpc_endpoint_id;
299 	u8		recvmsg_inq:1,
300 			cork:1,
301 			nodelay:1,
302 			fastopening:1,
303 			in_accept_queue:1,
304 			free_first:1,
305 			rcvspace_init:1;
306 	struct work_struct work;
307 	struct sk_buff  *ooo_last_skb;
308 	struct rb_root  out_of_order_queue;
309 	struct sk_buff_head receive_queue;
310 	struct list_head conn_list;
311 	struct list_head rtx_queue;
312 	struct mptcp_data_frag *first_pending;
313 	struct list_head join_list;
314 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
315 				 * ONCE annotation, the subflow outside the socket
316 				 * lock as such sock is freed after close().
317 				 */
318 	struct mptcp_pm_data	pm;
319 	struct mptcp_sched_ops	*sched;
320 	struct {
321 		u32	space;	/* bytes copied in last measurement window */
322 		u32	copied; /* bytes copied in this measurement window */
323 		u64	time;	/* start time of measurement window */
324 		u64	rtt_us; /* last maximum rtt of subflows */
325 	} rcvq_space;
326 	u8		scaling_ratio;
327 
328 	u32		subflow_id;
329 	u32		setsockopt_seq;
330 	char		ca_name[TCP_CA_NAME_MAX];
331 };
332 
333 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
334 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
335 
336 #define mptcp_for_each_subflow(__msk, __subflow)			\
337 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
338 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
339 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
340 
341 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
342 {
343 	sock_owned_by_me((const struct sock *)msk);
344 }
345 
346 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
347 
348 /* the msk socket don't use the backlog, also account for the bulk
349  * free memory
350  */
351 static inline int __mptcp_rmem(const struct sock *sk)
352 {
353 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
354 }
355 
356 static inline int mptcp_win_from_space(const struct sock *sk, int space)
357 {
358 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
359 }
360 
361 static inline int __mptcp_space(const struct sock *sk)
362 {
363 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
364 }
365 
366 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
367 {
368 	const struct mptcp_sock *msk = mptcp_sk(sk);
369 
370 	return READ_ONCE(msk->first_pending);
371 }
372 
373 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
374 {
375 	struct mptcp_sock *msk = mptcp_sk(sk);
376 	struct mptcp_data_frag *cur;
377 
378 	cur = msk->first_pending;
379 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
380 						     list_next_entry(cur, list);
381 }
382 
383 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
384 {
385 	const struct mptcp_sock *msk = mptcp_sk(sk);
386 
387 	if (!msk->first_pending)
388 		return NULL;
389 
390 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
391 		return NULL;
392 
393 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
394 }
395 
396 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
397 {
398 	struct mptcp_sock *msk = mptcp_sk(sk);
399 
400 	if (msk->snd_una == READ_ONCE(msk->snd_nxt))
401 		return NULL;
402 
403 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
404 }
405 
406 struct csum_pseudo_header {
407 	__be64 data_seq;
408 	__be32 subflow_seq;
409 	__be16 data_len;
410 	__sum16 csum;
411 };
412 
413 struct mptcp_subflow_request_sock {
414 	struct	tcp_request_sock sk;
415 	u16	mp_capable : 1,
416 		mp_join : 1,
417 		backup : 1,
418 		csum_reqd : 1,
419 		allow_join_id0 : 1;
420 	u8	local_id;
421 	u8	remote_id;
422 	u64	local_key;
423 	u64	idsn;
424 	u32	token;
425 	u32	ssn_offset;
426 	u64	thmac;
427 	u32	local_nonce;
428 	u32	remote_nonce;
429 	struct mptcp_sock	*msk;
430 	struct hlist_nulls_node token_node;
431 };
432 
433 static inline struct mptcp_subflow_request_sock *
434 mptcp_subflow_rsk(const struct request_sock *rsk)
435 {
436 	return (struct mptcp_subflow_request_sock *)rsk;
437 }
438 
439 enum mptcp_data_avail {
440 	MPTCP_SUBFLOW_NODATA,
441 	MPTCP_SUBFLOW_DATA_AVAIL,
442 };
443 
444 struct mptcp_delegated_action {
445 	struct napi_struct napi;
446 	struct list_head head;
447 };
448 
449 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
450 
451 #define MPTCP_DELEGATE_SCHEDULED	0
452 #define MPTCP_DELEGATE_SEND		1
453 #define MPTCP_DELEGATE_ACK		2
454 #define MPTCP_DELEGATE_SNDBUF		3
455 
456 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
457 /* MPTCP subflow context */
458 struct mptcp_subflow_context {
459 	struct	list_head node;/* conn_list of subflows */
460 
461 	struct_group(reset,
462 
463 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
464 	u64	local_key;
465 	u64	remote_key;
466 	u64	idsn;
467 	u64	map_seq;
468 	u32	snd_isn;
469 	u32	token;
470 	u32	rel_write_seq;
471 	u32	map_subflow_seq;
472 	u32	ssn_offset;
473 	u32	map_data_len;
474 	__wsum	map_data_csum;
475 	u32	map_csum_len;
476 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
477 		request_join : 1,   /* send MP_JOIN */
478 		request_bkup : 1,
479 		mp_capable : 1,	    /* remote is MPTCP capable */
480 		mp_join : 1,	    /* remote is JOINing */
481 		fully_established : 1,	    /* path validated */
482 		pm_notified : 1,    /* PM hook called for established status */
483 		conn_finished : 1,
484 		map_valid : 1,
485 		map_csum_reqd : 1,
486 		map_data_fin : 1,
487 		mpc_map : 1,
488 		backup : 1,
489 		send_mp_prio : 1,
490 		send_mp_fail : 1,
491 		send_fastclose : 1,
492 		send_infinite_map : 1,
493 		remote_key_valid : 1,        /* received the peer key from */
494 		disposable : 1,	    /* ctx can be free at ulp release time */
495 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
496 		local_id_valid : 1, /* local_id is correctly initialized */
497 		valid_csum_seen : 1,        /* at least one csum validated */
498 		is_mptfo : 1,	    /* subflow is doing TFO */
499 		__unused : 9;
500 	enum mptcp_data_avail data_avail;
501 	bool	scheduled;
502 	u32	remote_nonce;
503 	u64	thmac;
504 	u32	local_nonce;
505 	u32	remote_token;
506 	union {
507 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
508 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
509 	};
510 	u8	local_id;
511 	u8	remote_id;
512 	u8	reset_seen:1;
513 	u8	reset_transient:1;
514 	u8	reset_reason:4;
515 	u8	stale_count;
516 
517 	u32	subflow_id;
518 
519 	long	delegated_status;
520 	unsigned long	fail_tout;
521 
522 	);
523 
524 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
525 
526 	u32	setsockopt_seq;
527 	u32	stale_rcv_tstamp;
528 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
529 				     * protected by the msk socket lock
530 				     */
531 
532 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
533 	struct	sock *conn;	    /* parent mptcp_sock */
534 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
535 	void	(*tcp_state_change)(struct sock *sk);
536 	void	(*tcp_error_report)(struct sock *sk);
537 
538 	struct	rcu_head rcu;
539 };
540 
541 static inline struct mptcp_subflow_context *
542 mptcp_subflow_ctx(const struct sock *sk)
543 {
544 	struct inet_connection_sock *icsk = inet_csk(sk);
545 
546 	/* Use RCU on icsk_ulp_data only for sock diag code */
547 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
548 }
549 
550 static inline struct sock *
551 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
552 {
553 	return subflow->tcp_sock;
554 }
555 
556 static inline void
557 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
558 {
559 	memset(&subflow->reset, 0, sizeof(subflow->reset));
560 	subflow->request_mptcp = 1;
561 }
562 
563 static inline u64
564 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
565 {
566 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
567 		      subflow->ssn_offset -
568 		      subflow->map_subflow_seq;
569 }
570 
571 static inline u64
572 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
573 {
574 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
575 }
576 
577 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
578 
579 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
580 {
581 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
582 	struct mptcp_delegated_action *delegated;
583 	bool schedule;
584 
585 	/* the caller held the subflow bh socket lock */
586 	lockdep_assert_in_softirq();
587 
588 	/* The implied barrier pairs with tcp_release_cb_override()
589 	 * mptcp_napi_poll(), and ensures the below list check sees list
590 	 * updates done prior to delegated status bits changes
591 	 */
592 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
593 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
594 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
595 			return;
596 
597 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
598 		schedule = list_empty(&delegated->head);
599 		list_add_tail(&subflow->delegated_node, &delegated->head);
600 		sock_hold(mptcp_subflow_tcp_sock(subflow));
601 		if (schedule)
602 			napi_schedule(&delegated->napi);
603 	}
604 }
605 
606 static inline struct mptcp_subflow_context *
607 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
608 {
609 	struct mptcp_subflow_context *ret;
610 
611 	if (list_empty(&delegated->head))
612 		return NULL;
613 
614 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
615 	list_del_init(&ret->delegated_node);
616 	return ret;
617 }
618 
619 int mptcp_is_enabled(const struct net *net);
620 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
621 int mptcp_is_checksum_enabled(const struct net *net);
622 int mptcp_allow_join_id0(const struct net *net);
623 unsigned int mptcp_stale_loss_cnt(const struct net *net);
624 int mptcp_get_pm_type(const struct net *net);
625 const char *mptcp_get_scheduler(const struct net *net);
626 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
627 				       struct mptcp_subflow_context *subflow,
628 				       const struct mptcp_options_received *mp_opt);
629 bool __mptcp_retransmit_pending_data(struct sock *sk);
630 void mptcp_check_and_set_pending(struct sock *sk);
631 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
632 bool mptcp_subflow_data_available(struct sock *sk);
633 void __init mptcp_subflow_init(void);
634 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
635 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
636 		     struct mptcp_subflow_context *subflow);
637 void __mptcp_subflow_send_ack(struct sock *ssk);
638 void mptcp_subflow_reset(struct sock *ssk);
639 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
640 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
641 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
642 bool __mptcp_close(struct sock *sk, long timeout);
643 void mptcp_cancel_work(struct sock *sk);
644 void __mptcp_unaccepted_force_close(struct sock *sk);
645 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
646 void mptcp_set_state(struct sock *sk, int state);
647 
648 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
649 			   const struct mptcp_addr_info *b, bool use_port);
650 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
651 
652 /* called with sk socket lock held */
653 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
654 			    const struct mptcp_addr_info *remote);
655 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
656 				struct socket **new_sock);
657 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
658 			 struct sockaddr_storage *addr,
659 			 unsigned short family);
660 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
661 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
662 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
663 void mptcp_sched_init(void);
664 int mptcp_init_sched(struct mptcp_sock *msk,
665 		     struct mptcp_sched_ops *sched);
666 void mptcp_release_sched(struct mptcp_sock *msk);
667 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
668 				 bool scheduled);
669 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
670 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
671 int mptcp_sched_get_send(struct mptcp_sock *msk);
672 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
673 
674 static inline bool __tcp_can_send(const struct sock *ssk)
675 {
676 	/* only send if our side has not closed yet */
677 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
678 }
679 
680 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
681 {
682 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
683 	if (subflow->request_join && !subflow->fully_established)
684 		return false;
685 
686 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
687 }
688 
689 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
690 
691 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
692 
693 void mptcp_subflow_drop_ctx(struct sock *ssk);
694 
695 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
696 					      struct mptcp_subflow_context *ctx)
697 {
698 	sk->sk_data_ready = sock_def_readable;
699 	sk->sk_state_change = ctx->tcp_state_change;
700 	sk->sk_write_space = sk_stream_write_space;
701 	sk->sk_error_report = ctx->tcp_error_report;
702 
703 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
704 }
705 
706 void __init mptcp_proto_init(void);
707 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
708 int __init mptcp_proto_v6_init(void);
709 #endif
710 
711 struct sock *mptcp_sk_clone_init(const struct sock *sk,
712 				 const struct mptcp_options_received *mp_opt,
713 				 struct sock *ssk,
714 				 struct request_sock *req);
715 void mptcp_get_options(const struct sk_buff *skb,
716 		       struct mptcp_options_received *mp_opt);
717 
718 void mptcp_finish_connect(struct sock *sk);
719 void __mptcp_sync_state(struct sock *sk, int state);
720 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
721 
722 static inline void mptcp_stop_tout_timer(struct sock *sk)
723 {
724 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
725 		return;
726 
727 	sk_stop_timer(sk, &sk->sk_timer);
728 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
729 }
730 
731 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
732 {
733 	/* avoid 0 timestamp, as that means no close timeout */
734 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
735 }
736 
737 static inline void mptcp_start_tout_timer(struct sock *sk)
738 {
739 	mptcp_set_close_tout(sk, tcp_jiffies32);
740 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
741 }
742 
743 static inline bool mptcp_is_fully_established(struct sock *sk)
744 {
745 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
746 	       READ_ONCE(mptcp_sk(sk)->fully_established);
747 }
748 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
749 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
750 bool mptcp_finish_join(struct sock *sk);
751 bool mptcp_schedule_work(struct sock *sk);
752 int mptcp_setsockopt(struct sock *sk, int level, int optname,
753 		     sockptr_t optval, unsigned int optlen);
754 int mptcp_getsockopt(struct sock *sk, int level, int optname,
755 		     char __user *optval, int __user *option);
756 
757 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
758 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
759 {
760 	if (use_64bit)
761 		return cur_seq;
762 
763 	return __mptcp_expand_seq(old_seq, cur_seq);
764 }
765 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
766 void __mptcp_data_acked(struct sock *sk);
767 void __mptcp_error_report(struct sock *sk);
768 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
769 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
770 {
771 	return READ_ONCE(msk->snd_data_fin_enable) &&
772 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
773 }
774 
775 static inline void __mptcp_sync_sndbuf(struct sock *sk)
776 {
777 	struct mptcp_subflow_context *subflow;
778 	int ssk_sndbuf, new_sndbuf;
779 
780 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
781 		return;
782 
783 	new_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[0];
784 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
785 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
786 
787 		subflow->cached_sndbuf = ssk_sndbuf;
788 		new_sndbuf += ssk_sndbuf;
789 	}
790 
791 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
792 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
793 }
794 
795 /* The called held both the msk socket and the subflow socket locks,
796  * possibly under BH
797  */
798 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
799 {
800 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
801 
802 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
803 		__mptcp_sync_sndbuf(sk);
804 }
805 
806 /* the caller held only the subflow socket lock, either in process or
807  * BH context. Additionally this can be called under the msk data lock,
808  * so we can't acquire such lock here: let the delegate action acquires
809  * the needed locks in suitable order.
810  */
811 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
812 {
813 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
814 
815 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
816 		return;
817 
818 	local_bh_disable();
819 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
820 	local_bh_enable();
821 }
822 
823 static inline void mptcp_write_space(struct sock *sk)
824 {
825 	if (sk_stream_is_writeable(sk)) {
826 		/* pairs with memory barrier in mptcp_poll */
827 		smp_mb();
828 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
829 			sk_stream_write_space(sk);
830 	}
831 }
832 
833 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
834 
835 #define MPTCP_TOKEN_MAX_RETRIES	4
836 
837 void __init mptcp_token_init(void);
838 static inline void mptcp_token_init_request(struct request_sock *req)
839 {
840 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
841 }
842 
843 int mptcp_token_new_request(struct request_sock *req);
844 void mptcp_token_destroy_request(struct request_sock *req);
845 int mptcp_token_new_connect(struct sock *ssk);
846 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
847 			struct mptcp_sock *msk);
848 bool mptcp_token_exists(u32 token);
849 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
850 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
851 					 long *s_num);
852 void mptcp_token_destroy(struct mptcp_sock *msk);
853 
854 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
855 
856 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
857 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
858 
859 void __init mptcp_pm_init(void);
860 void mptcp_pm_data_init(struct mptcp_sock *msk);
861 void mptcp_pm_data_reset(struct mptcp_sock *msk);
862 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
863 			struct mptcp_addr_info *addr);
864 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
865 			 bool require_family,
866 			 struct mptcp_pm_addr_entry *entry);
867 bool mptcp_pm_addr_families_match(const struct sock *sk,
868 				  const struct mptcp_addr_info *loc,
869 				  const struct mptcp_addr_info *rem);
870 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
871 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
872 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
873 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
874 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
875 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
876 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
877 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
878 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk,
879 				 const struct mptcp_subflow_context *subflow);
880 void mptcp_pm_add_addr_received(const struct sock *ssk,
881 				const struct mptcp_addr_info *addr);
882 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
883 			      const struct mptcp_addr_info *addr);
884 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
885 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
886 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
887 			       const struct mptcp_rm_list *rm_list);
888 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
889 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
890 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
891 				 struct mptcp_addr_info *addr,
892 				 struct mptcp_addr_info *rem,
893 				 u8 bkup);
894 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
895 			      const struct mptcp_addr_info *addr);
896 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
897 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
898 struct mptcp_pm_add_entry *
899 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
900 		       const struct mptcp_addr_info *addr, bool check_id);
901 struct mptcp_pm_add_entry *
902 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
903 				const struct mptcp_addr_info *addr);
904 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
905 					 unsigned int id,
906 					 u8 *flags, int *ifindex);
907 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
908 					    u8 *flags, int *ifindex);
909 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
910 						   unsigned int id,
911 						   u8 *flags, int *ifindex);
912 int mptcp_pm_set_flags(struct net *net, struct nlattr *token,
913 		       struct mptcp_pm_addr_entry *loc,
914 		       struct mptcp_pm_addr_entry *rem, u8 bkup);
915 int mptcp_pm_nl_set_flags(struct net *net, struct mptcp_pm_addr_entry *addr, u8 bkup);
916 int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
917 				 struct mptcp_pm_addr_entry *loc,
918 				 struct mptcp_pm_addr_entry *rem, u8 bkup);
919 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
920 			   const struct mptcp_addr_info *addr,
921 			   bool echo);
922 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
923 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
924 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
925 void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
926 					struct list_head *rm_list);
927 
928 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
929 int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info);
930 int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info);
931 int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info);
932 int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info);
933 
934 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
935 		 const struct sock *ssk, gfp_t gfp);
936 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
937 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
938 void mptcp_event_pm_listener(const struct sock *ssk,
939 			     enum mptcp_event_type event);
940 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
941 
942 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
943 				     const struct mptcp_options_received *mp_opt);
944 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
945 					      struct request_sock *req);
946 
947 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
948 {
949 	return READ_ONCE(msk->pm.addr_signal) &
950 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
951 }
952 
953 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
954 {
955 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
956 }
957 
958 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
959 {
960 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
961 }
962 
963 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
964 {
965 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
966 }
967 
968 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
969 {
970 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
971 }
972 
973 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
974 {
975 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
976 }
977 
978 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
979 {
980 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
981 
982 	if (family == AF_INET6)
983 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
984 	if (!echo)
985 		len += MPTCPOPT_THMAC_LEN;
986 	/* account for 2 trailing 'nop' options */
987 	if (port)
988 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
989 
990 	return len;
991 }
992 
993 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
994 {
995 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
996 		return -EINVAL;
997 
998 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
999 }
1000 
1001 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1002 			      unsigned int opt_size, unsigned int remaining,
1003 			      struct mptcp_addr_info *addr, bool *echo,
1004 			      bool *drop_other_suboptions);
1005 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1006 			     struct mptcp_rm_list *rm_list);
1007 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1008 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1009 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1010 
1011 void __init mptcp_pm_nl_init(void);
1012 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1013 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1014 				     const struct mptcp_rm_list *rm_list);
1015 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1016 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1017 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1018 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1019 
1020 /* called under PM lock */
1021 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1022 {
1023 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1024 		WRITE_ONCE(msk->pm.accept_subflow, true);
1025 }
1026 
1027 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1028 {
1029 	spin_lock_bh(&msk->pm.lock);
1030 	__mptcp_pm_close_subflow(msk);
1031 	spin_unlock_bh(&msk->pm.lock);
1032 }
1033 
1034 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1035 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1036 
1037 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1038 {
1039 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1040 }
1041 
1042 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1043 
1044 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1045 {
1046 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1047 }
1048 
1049 static inline bool mptcp_check_fallback(const struct sock *sk)
1050 {
1051 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1052 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1053 
1054 	return __mptcp_check_fallback(msk);
1055 }
1056 
1057 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1058 {
1059 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
1060 		pr_debug("TCP fallback already done (msk=%p)", msk);
1061 		return;
1062 	}
1063 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1064 }
1065 
1066 static inline void mptcp_do_fallback(struct sock *ssk)
1067 {
1068 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1069 	struct sock *sk = subflow->conn;
1070 	struct mptcp_sock *msk;
1071 
1072 	msk = mptcp_sk(sk);
1073 	__mptcp_do_fallback(msk);
1074 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1075 		gfp_t saved_allocation = ssk->sk_allocation;
1076 
1077 		/* we are in a atomic (BH) scope, override ssk default for data
1078 		 * fin allocation
1079 		 */
1080 		ssk->sk_allocation = GFP_ATOMIC;
1081 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1082 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1083 		ssk->sk_allocation = saved_allocation;
1084 	}
1085 }
1086 
1087 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1088 
1089 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1090 {
1091 	struct mptcp_ext *mpext;
1092 
1093 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1094 	if (mpext && mpext->infinite_map)
1095 		return true;
1096 
1097 	return false;
1098 }
1099 
1100 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1101 {
1102 	return (subflow->request_mptcp || subflow->request_join);
1103 }
1104 
1105 static inline bool subflow_simultaneous_connect(struct sock *sk)
1106 {
1107 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1108 
1109 	return (1 << sk->sk_state) &
1110 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1111 	       is_active_ssk(subflow) &&
1112 	       !subflow->conn_finished;
1113 }
1114 
1115 #ifdef CONFIG_SYN_COOKIES
1116 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1117 				       struct sk_buff *skb);
1118 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1119 					struct sk_buff *skb);
1120 void __init mptcp_join_cookie_init(void);
1121 #else
1122 static inline void
1123 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1124 				  struct sk_buff *skb) {}
1125 static inline bool
1126 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1127 				   struct sk_buff *skb)
1128 {
1129 	return false;
1130 }
1131 
1132 static inline void mptcp_join_cookie_init(void) {}
1133 #endif
1134 
1135 #endif /* __MPTCP_PROTOCOL_H */
1136