xref: /linux/net/mptcp/protocol.h (revision ee975351cf0c2a11cdf97eae58265c126cb32850)
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_NOSPACE		1
117 #define MPTCP_WORK_RTX		2
118 #define MPTCP_FALLBACK_DONE	4
119 #define MPTCP_WORK_CLOSE_SUBFLOW 5
120 
121 /* MPTCP socket release cb flags */
122 #define MPTCP_PUSH_PENDING	1
123 #define MPTCP_CLEAN_UNA		2
124 #define MPTCP_ERROR_REPORT	3
125 #define MPTCP_RETRANSMIT	4
126 #define MPTCP_FLUSH_JOIN_LIST	5
127 #define MPTCP_SYNC_STATE	6
128 #define MPTCP_SYNC_SNDBUF	7
129 
130 struct mptcp_skb_cb {
131 	u64 map_seq;
132 	u64 end_seq;
133 	u32 offset;
134 	u8  has_rxtstamp:1;
135 };
136 
137 #define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
138 
139 static inline bool before64(__u64 seq1, __u64 seq2)
140 {
141 	return (__s64)(seq1 - seq2) < 0;
142 }
143 
144 #define after64(seq2, seq1)	before64(seq1, seq2)
145 
146 struct mptcp_options_received {
147 	u64	sndr_key;
148 	u64	rcvr_key;
149 	u64	data_ack;
150 	u64	data_seq;
151 	u32	subflow_seq;
152 	u16	data_len;
153 	__sum16	csum;
154 	u16	suboptions;
155 	u32	token;
156 	u32	nonce;
157 	u16	use_map:1,
158 		dsn64:1,
159 		data_fin:1,
160 		use_ack:1,
161 		ack64:1,
162 		mpc_map:1,
163 		reset_reason:4,
164 		reset_transient:1,
165 		echo:1,
166 		backup:1,
167 		deny_join_id0:1,
168 		__unused:2;
169 	u8	join_id;
170 	u64	thmac;
171 	u8	hmac[MPTCPOPT_HMAC_LEN];
172 	struct mptcp_addr_info addr;
173 	struct mptcp_rm_list rm_list;
174 	u64	ahmac;
175 	u64	fail_seq;
176 };
177 
178 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
179 {
180 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
181 		     ((nib & 0xF) << 8) | field);
182 }
183 
184 enum mptcp_pm_status {
185 	MPTCP_PM_ADD_ADDR_RECEIVED,
186 	MPTCP_PM_ADD_ADDR_SEND_ACK,
187 	MPTCP_PM_RM_ADDR_RECEIVED,
188 	MPTCP_PM_ESTABLISHED,
189 	MPTCP_PM_SUBFLOW_ESTABLISHED,
190 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
191 	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
192 					 * accounted int id_avail_bitmap
193 					 */
194 };
195 
196 enum mptcp_pm_type {
197 	MPTCP_PM_TYPE_KERNEL = 0,
198 	MPTCP_PM_TYPE_USERSPACE,
199 
200 	__MPTCP_PM_TYPE_NR,
201 	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
202 };
203 
204 /* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */
205 #define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)
206 
207 enum mptcp_addr_signal_status {
208 	MPTCP_ADD_ADDR_SIGNAL,
209 	MPTCP_ADD_ADDR_ECHO,
210 	MPTCP_RM_ADDR_SIGNAL,
211 };
212 
213 /* max value of mptcp_addr_info.id */
214 #define MPTCP_PM_MAX_ADDR_ID		U8_MAX
215 
216 struct mptcp_pm_data {
217 	struct mptcp_addr_info local;
218 	struct mptcp_addr_info remote;
219 	struct list_head anno_list;
220 	struct list_head userspace_pm_local_addr_list;
221 
222 	spinlock_t	lock;		/*protects the whole PM data */
223 
224 	u8		addr_signal;
225 	bool		server_side;
226 	bool		work_pending;
227 	bool		accept_addr;
228 	bool		accept_subflow;
229 	bool		remote_deny_join_id0;
230 	u8		add_addr_signaled;
231 	u8		add_addr_accepted;
232 	u8		local_addr_used;
233 	u8		pm_type;
234 	u8		subflows;
235 	u8		status;
236 	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
237 	struct mptcp_rm_list rm_list_tx;
238 	struct mptcp_rm_list rm_list_rx;
239 };
240 
241 struct mptcp_pm_addr_entry {
242 	struct list_head	list;
243 	struct mptcp_addr_info	addr;
244 	u8			flags;
245 	int			ifindex;
246 	struct socket		*lsk;
247 };
248 
249 struct mptcp_data_frag {
250 	struct list_head list;
251 	u64 data_seq;
252 	u16 data_len;
253 	u16 offset;
254 	u16 overhead;
255 	u16 already_sent;
256 	struct page *page;
257 };
258 
259 /* MPTCP connection sock */
260 struct mptcp_sock {
261 	/* inet_connection_sock must be the first member */
262 	struct inet_connection_sock sk;
263 	u64		local_key;		/* protected by the first subflow socket lock
264 						 * lockless access read
265 						 */
266 	u64		remote_key;		/* same as above */
267 	u64		write_seq;
268 	u64		bytes_sent;
269 	u64		snd_nxt;
270 	u64		bytes_received;
271 	u64		ack_seq;
272 	atomic64_t	rcv_wnd_sent;
273 	u64		rcv_data_fin_seq;
274 	u64		bytes_retrans;
275 	u64		bytes_consumed;
276 	int		rmem_fwd_alloc;
277 	int		snd_burst;
278 	int		old_wspace;
279 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
280 						 * recovery related fields are under data_lock
281 						 * protection
282 						 */
283 	u64		bytes_acked;
284 	u64		snd_una;
285 	u64		wnd_end;
286 	unsigned long	timer_ival;
287 	u32		token;
288 	int		rmem_released;
289 	unsigned long	flags;
290 	unsigned long	cb_flags;
291 	bool		recovery;		/* closing subflow write queue reinjected */
292 	bool		can_ack;
293 	bool		fully_established;
294 	bool		rcv_data_fin;
295 	bool		snd_data_fin_enable;
296 	bool		rcv_fastclose;
297 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
298 	bool		csum_enabled;
299 	bool		allow_infinite_fallback;
300 	u8		pending_state; /* A subflow asked to set this sk_state,
301 					* protected by the msk data lock
302 					*/
303 	u8		mpc_endpoint_id;
304 	u8		recvmsg_inq:1,
305 			cork:1,
306 			nodelay:1,
307 			fastopening:1,
308 			in_accept_queue:1,
309 			free_first:1,
310 			rcvspace_init:1;
311 	struct work_struct work;
312 	struct sk_buff  *ooo_last_skb;
313 	struct rb_root  out_of_order_queue;
314 	struct sk_buff_head receive_queue;
315 	struct list_head conn_list;
316 	struct list_head rtx_queue;
317 	struct mptcp_data_frag *first_pending;
318 	struct list_head join_list;
319 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
320 				 * ONCE annotation, the subflow outside the socket
321 				 * lock as such sock is freed after close().
322 				 */
323 	struct mptcp_pm_data	pm;
324 	struct mptcp_sched_ops	*sched;
325 	struct {
326 		u32	space;	/* bytes copied in last measurement window */
327 		u32	copied; /* bytes copied in this measurement window */
328 		u64	time;	/* start time of measurement window */
329 		u64	rtt_us; /* last maximum rtt of subflows */
330 	} rcvq_space;
331 	u8		scaling_ratio;
332 
333 	u32		subflow_id;
334 	u32		setsockopt_seq;
335 	char		ca_name[TCP_CA_NAME_MAX];
336 };
337 
338 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
339 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
340 
341 #define mptcp_for_each_subflow(__msk, __subflow)			\
342 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
343 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
344 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
345 
346 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
347 {
348 	sock_owned_by_me((const struct sock *)msk);
349 }
350 
351 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
352 
353 /* the msk socket don't use the backlog, also account for the bulk
354  * free memory
355  */
356 static inline int __mptcp_rmem(const struct sock *sk)
357 {
358 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
359 }
360 
361 static inline int mptcp_win_from_space(const struct sock *sk, int space)
362 {
363 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
364 }
365 
366 static inline int __mptcp_space(const struct sock *sk)
367 {
368 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
369 }
370 
371 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
372 {
373 	const struct mptcp_sock *msk = mptcp_sk(sk);
374 
375 	return READ_ONCE(msk->first_pending);
376 }
377 
378 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
379 {
380 	struct mptcp_sock *msk = mptcp_sk(sk);
381 	struct mptcp_data_frag *cur;
382 
383 	cur = msk->first_pending;
384 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
385 						     list_next_entry(cur, list);
386 }
387 
388 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
389 {
390 	const struct mptcp_sock *msk = mptcp_sk(sk);
391 
392 	if (!msk->first_pending)
393 		return NULL;
394 
395 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
396 		return NULL;
397 
398 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
399 }
400 
401 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
402 {
403 	struct mptcp_sock *msk = mptcp_sk(sk);
404 
405 	if (msk->snd_una == msk->snd_nxt)
406 		return NULL;
407 
408 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
409 }
410 
411 struct csum_pseudo_header {
412 	__be64 data_seq;
413 	__be32 subflow_seq;
414 	__be16 data_len;
415 	__sum16 csum;
416 };
417 
418 struct mptcp_subflow_request_sock {
419 	struct	tcp_request_sock sk;
420 	u16	mp_capable : 1,
421 		mp_join : 1,
422 		backup : 1,
423 		csum_reqd : 1,
424 		allow_join_id0 : 1;
425 	u8	local_id;
426 	u8	remote_id;
427 	u64	local_key;
428 	u64	idsn;
429 	u32	token;
430 	u32	ssn_offset;
431 	u64	thmac;
432 	u32	local_nonce;
433 	u32	remote_nonce;
434 	struct mptcp_sock	*msk;
435 	struct hlist_nulls_node token_node;
436 };
437 
438 static inline struct mptcp_subflow_request_sock *
439 mptcp_subflow_rsk(const struct request_sock *rsk)
440 {
441 	return (struct mptcp_subflow_request_sock *)rsk;
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 	bool	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 unsigned int mptcp_close_timeout(const struct sock *sk);
625 int mptcp_get_pm_type(const struct net *net);
626 const char *mptcp_get_scheduler(const struct net *net);
627 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
628 				       struct mptcp_subflow_context *subflow,
629 				       const struct mptcp_options_received *mp_opt);
630 bool __mptcp_retransmit_pending_data(struct sock *sk);
631 void mptcp_check_and_set_pending(struct sock *sk);
632 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
633 bool mptcp_subflow_data_available(struct sock *sk);
634 void __init mptcp_subflow_init(void);
635 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
636 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
637 		     struct mptcp_subflow_context *subflow);
638 void __mptcp_subflow_send_ack(struct sock *ssk);
639 void mptcp_subflow_reset(struct sock *ssk);
640 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
641 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
642 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
643 bool __mptcp_close(struct sock *sk, long timeout);
644 void mptcp_cancel_work(struct sock *sk);
645 void __mptcp_unaccepted_force_close(struct sock *sk);
646 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
647 void mptcp_set_state(struct sock *sk, int state);
648 
649 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
650 			   const struct mptcp_addr_info *b, bool use_port);
651 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
652 
653 /* called with sk socket lock held */
654 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
655 			    const struct mptcp_addr_info *remote);
656 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
657 				struct socket **new_sock);
658 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
659 			 struct sockaddr_storage *addr,
660 			 unsigned short family);
661 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
662 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
663 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
664 void mptcp_sched_init(void);
665 int mptcp_init_sched(struct mptcp_sock *msk,
666 		     struct mptcp_sched_ops *sched);
667 void mptcp_release_sched(struct mptcp_sock *msk);
668 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
669 				 bool scheduled);
670 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
671 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
672 int mptcp_sched_get_send(struct mptcp_sock *msk);
673 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
674 
675 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
676 {
677 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
678 }
679 
680 static inline bool mptcp_epollin_ready(const struct sock *sk)
681 {
682 	/* mptcp doesn't have to deal with small skbs in the receive queue,
683 	 * at it can always coalesce them
684 	 */
685 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
686 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
687 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
688 	       READ_ONCE(tcp_memory_pressure);
689 }
690 
691 int mptcp_set_rcvlowat(struct sock *sk, int val);
692 
693 static inline bool __tcp_can_send(const struct sock *ssk)
694 {
695 	/* only send if our side has not closed yet */
696 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
697 }
698 
699 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
700 {
701 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
702 	if (subflow->request_join && !subflow->fully_established)
703 		return false;
704 
705 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
706 }
707 
708 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
709 
710 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
711 
712 void mptcp_subflow_drop_ctx(struct sock *ssk);
713 
714 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
715 					      struct mptcp_subflow_context *ctx)
716 {
717 	sk->sk_data_ready = sock_def_readable;
718 	sk->sk_state_change = ctx->tcp_state_change;
719 	sk->sk_write_space = sk_stream_write_space;
720 	sk->sk_error_report = ctx->tcp_error_report;
721 
722 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
723 }
724 
725 void __init mptcp_proto_init(void);
726 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
727 int __init mptcp_proto_v6_init(void);
728 #endif
729 
730 struct sock *mptcp_sk_clone_init(const struct sock *sk,
731 				 const struct mptcp_options_received *mp_opt,
732 				 struct sock *ssk,
733 				 struct request_sock *req);
734 void mptcp_get_options(const struct sk_buff *skb,
735 		       struct mptcp_options_received *mp_opt);
736 
737 void mptcp_finish_connect(struct sock *sk);
738 void __mptcp_sync_state(struct sock *sk, int state);
739 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
740 
741 static inline void mptcp_stop_tout_timer(struct sock *sk)
742 {
743 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
744 		return;
745 
746 	sk_stop_timer(sk, &sk->sk_timer);
747 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
748 }
749 
750 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
751 {
752 	/* avoid 0 timestamp, as that means no close timeout */
753 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
754 }
755 
756 static inline void mptcp_start_tout_timer(struct sock *sk)
757 {
758 	mptcp_set_close_tout(sk, tcp_jiffies32);
759 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
760 }
761 
762 static inline bool mptcp_is_fully_established(struct sock *sk)
763 {
764 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
765 	       READ_ONCE(mptcp_sk(sk)->fully_established);
766 }
767 
768 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
769 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
770 bool mptcp_finish_join(struct sock *sk);
771 bool mptcp_schedule_work(struct sock *sk);
772 int mptcp_setsockopt(struct sock *sk, int level, int optname,
773 		     sockptr_t optval, unsigned int optlen);
774 int mptcp_getsockopt(struct sock *sk, int level, int optname,
775 		     char __user *optval, int __user *option);
776 
777 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
778 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
779 {
780 	if (use_64bit)
781 		return cur_seq;
782 
783 	return __mptcp_expand_seq(old_seq, cur_seq);
784 }
785 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
786 void __mptcp_data_acked(struct sock *sk);
787 void __mptcp_error_report(struct sock *sk);
788 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
789 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
790 {
791 	return READ_ONCE(msk->snd_data_fin_enable) &&
792 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
793 }
794 
795 static inline void __mptcp_sync_sndbuf(struct sock *sk)
796 {
797 	struct mptcp_subflow_context *subflow;
798 	int ssk_sndbuf, new_sndbuf;
799 
800 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
801 		return;
802 
803 	new_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[0];
804 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
805 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
806 
807 		subflow->cached_sndbuf = ssk_sndbuf;
808 		new_sndbuf += ssk_sndbuf;
809 	}
810 
811 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
812 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
813 }
814 
815 /* The called held both the msk socket and the subflow socket locks,
816  * possibly under BH
817  */
818 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
819 {
820 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
821 
822 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
823 		__mptcp_sync_sndbuf(sk);
824 }
825 
826 /* the caller held only the subflow socket lock, either in process or
827  * BH context. Additionally this can be called under the msk data lock,
828  * so we can't acquire such lock here: let the delegate action acquires
829  * the needed locks in suitable order.
830  */
831 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
832 {
833 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
834 
835 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
836 		return;
837 
838 	local_bh_disable();
839 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
840 	local_bh_enable();
841 }
842 
843 static inline void mptcp_write_space(struct sock *sk)
844 {
845 	if (sk_stream_is_writeable(sk)) {
846 		/* pairs with memory barrier in mptcp_poll */
847 		smp_mb();
848 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
849 			sk_stream_write_space(sk);
850 	}
851 }
852 
853 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
854 
855 #define MPTCP_TOKEN_MAX_RETRIES	4
856 
857 void __init mptcp_token_init(void);
858 static inline void mptcp_token_init_request(struct request_sock *req)
859 {
860 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
861 }
862 
863 int mptcp_token_new_request(struct request_sock *req);
864 void mptcp_token_destroy_request(struct request_sock *req);
865 int mptcp_token_new_connect(struct sock *ssk);
866 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
867 			struct mptcp_sock *msk);
868 bool mptcp_token_exists(u32 token);
869 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
870 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
871 					 long *s_num);
872 void mptcp_token_destroy(struct mptcp_sock *msk);
873 
874 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
875 
876 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
877 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
878 
879 void __init mptcp_pm_init(void);
880 void mptcp_pm_data_init(struct mptcp_sock *msk);
881 void mptcp_pm_data_reset(struct mptcp_sock *msk);
882 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
883 			struct mptcp_addr_info *addr);
884 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
885 			 bool require_family,
886 			 struct mptcp_pm_addr_entry *entry);
887 bool mptcp_pm_addr_families_match(const struct sock *sk,
888 				  const struct mptcp_addr_info *loc,
889 				  const struct mptcp_addr_info *rem);
890 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
891 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
892 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
893 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
894 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
895 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
896 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
897 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
898 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
899 				 const struct mptcp_subflow_context *subflow);
900 void mptcp_pm_add_addr_received(const struct sock *ssk,
901 				const struct mptcp_addr_info *addr);
902 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
903 			      const struct mptcp_addr_info *addr);
904 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
905 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
906 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
907 			       const struct mptcp_rm_list *rm_list);
908 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
909 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
910 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
911 				 struct mptcp_addr_info *addr,
912 				 struct mptcp_addr_info *rem,
913 				 u8 bkup);
914 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
915 			      const struct mptcp_addr_info *addr);
916 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
917 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
918 struct mptcp_pm_add_entry *
919 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
920 		       const struct mptcp_addr_info *addr, bool check_id);
921 struct mptcp_pm_add_entry *
922 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
923 				const struct mptcp_addr_info *addr);
924 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
925 					 unsigned int id,
926 					 u8 *flags, int *ifindex);
927 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
928 					    u8 *flags, int *ifindex);
929 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
930 						   unsigned int id,
931 						   u8 *flags, int *ifindex);
932 int mptcp_pm_set_flags(struct net *net, struct nlattr *token,
933 		       struct mptcp_pm_addr_entry *loc,
934 		       struct mptcp_pm_addr_entry *rem, u8 bkup);
935 int mptcp_pm_nl_set_flags(struct net *net, struct mptcp_pm_addr_entry *addr, u8 bkup);
936 int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
937 				 struct mptcp_pm_addr_entry *loc,
938 				 struct mptcp_pm_addr_entry *rem, u8 bkup);
939 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
940 			   const struct mptcp_addr_info *addr,
941 			   bool echo);
942 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
943 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
944 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
945 void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
946 					struct list_head *rm_list);
947 
948 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
949 
950 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
951 		 const struct sock *ssk, gfp_t gfp);
952 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
953 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
954 void mptcp_event_pm_listener(const struct sock *ssk,
955 			     enum mptcp_event_type event);
956 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
957 
958 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
959 				     const struct mptcp_options_received *mp_opt);
960 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
961 					      struct request_sock *req);
962 
963 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
964 {
965 	return READ_ONCE(msk->pm.addr_signal) &
966 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
967 }
968 
969 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
970 {
971 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
972 }
973 
974 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
975 {
976 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
977 }
978 
979 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
980 {
981 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
982 }
983 
984 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
985 {
986 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
987 }
988 
989 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
990 {
991 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
992 }
993 
994 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
995 {
996 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
997 
998 	if (family == AF_INET6)
999 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1000 	if (!echo)
1001 		len += MPTCPOPT_THMAC_LEN;
1002 	/* account for 2 trailing 'nop' options */
1003 	if (port)
1004 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1005 
1006 	return len;
1007 }
1008 
1009 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1010 {
1011 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1012 		return -EINVAL;
1013 
1014 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1015 }
1016 
1017 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1018 			      unsigned int opt_size, unsigned int remaining,
1019 			      struct mptcp_addr_info *addr, bool *echo,
1020 			      bool *drop_other_suboptions);
1021 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1022 			     struct mptcp_rm_list *rm_list);
1023 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1024 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1025 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1026 
1027 void __init mptcp_pm_nl_init(void);
1028 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1029 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1030 				     const struct mptcp_rm_list *rm_list);
1031 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1032 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1033 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1034 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1035 
1036 /* called under PM lock */
1037 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1038 {
1039 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1040 		WRITE_ONCE(msk->pm.accept_subflow, true);
1041 }
1042 
1043 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1044 {
1045 	spin_lock_bh(&msk->pm.lock);
1046 	__mptcp_pm_close_subflow(msk);
1047 	spin_unlock_bh(&msk->pm.lock);
1048 }
1049 
1050 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1051 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1052 
1053 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1054 {
1055 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1056 }
1057 
1058 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1059 
1060 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1061 {
1062 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1063 }
1064 
1065 static inline bool mptcp_check_fallback(const struct sock *sk)
1066 {
1067 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1068 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1069 
1070 	return __mptcp_check_fallback(msk);
1071 }
1072 
1073 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1074 {
1075 	if (__mptcp_check_fallback(msk)) {
1076 		pr_debug("TCP fallback already done (msk=%p)", msk);
1077 		return;
1078 	}
1079 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1080 }
1081 
1082 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1083 {
1084 	struct sock *ssk = READ_ONCE(msk->first);
1085 
1086 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1087 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1088 			TCPF_SYN_RECV | TCPF_LISTEN));
1089 }
1090 
1091 static inline void mptcp_do_fallback(struct sock *ssk)
1092 {
1093 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1094 	struct sock *sk = subflow->conn;
1095 	struct mptcp_sock *msk;
1096 
1097 	msk = mptcp_sk(sk);
1098 	__mptcp_do_fallback(msk);
1099 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1100 		gfp_t saved_allocation = ssk->sk_allocation;
1101 
1102 		/* we are in a atomic (BH) scope, override ssk default for data
1103 		 * fin allocation
1104 		 */
1105 		ssk->sk_allocation = GFP_ATOMIC;
1106 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1107 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1108 		ssk->sk_allocation = saved_allocation;
1109 	}
1110 }
1111 
1112 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1113 
1114 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1115 {
1116 	struct mptcp_ext *mpext;
1117 
1118 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1119 	if (mpext && mpext->infinite_map)
1120 		return true;
1121 
1122 	return false;
1123 }
1124 
1125 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1126 {
1127 	return (subflow->request_mptcp || subflow->request_join);
1128 }
1129 
1130 static inline bool subflow_simultaneous_connect(struct sock *sk)
1131 {
1132 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1133 
1134 	return (1 << sk->sk_state) &
1135 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1136 	       is_active_ssk(subflow) &&
1137 	       !subflow->conn_finished;
1138 }
1139 
1140 #ifdef CONFIG_SYN_COOKIES
1141 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1142 				       struct sk_buff *skb);
1143 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1144 					struct sk_buff *skb);
1145 void __init mptcp_join_cookie_init(void);
1146 #else
1147 static inline void
1148 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1149 				  struct sk_buff *skb) {}
1150 static inline bool
1151 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1152 				   struct sk_buff *skb)
1153 {
1154 	return false;
1155 }
1156 
1157 static inline void mptcp_join_cookie_init(void) {}
1158 #endif
1159 
1160 #endif /* __MPTCP_PROTOCOL_H */
1161