xref: /linux/net/mptcp/protocol.h (revision 45d8b572fac3aa8b49d53c946b3685eaf78a2824)
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 	unsigned long	timer_ival;
286 	u32		token;
287 	int		rmem_released;
288 	unsigned long	flags;
289 	unsigned long	cb_flags;
290 	bool		recovery;		/* closing subflow write queue reinjected */
291 	bool		can_ack;
292 	bool		fully_established;
293 	bool		rcv_data_fin;
294 	bool		snd_data_fin_enable;
295 	bool		rcv_fastclose;
296 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
297 	bool		csum_enabled;
298 	bool		allow_infinite_fallback;
299 	u8		pending_state; /* A subflow asked to set this sk_state,
300 					* protected by the msk data lock
301 					*/
302 	u8		mpc_endpoint_id;
303 	u8		recvmsg_inq:1,
304 			cork:1,
305 			nodelay:1,
306 			fastopening:1,
307 			in_accept_queue:1,
308 			free_first:1,
309 			rcvspace_init:1;
310 	u32		notsent_lowat;
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 extern struct genl_family mptcp_genl_family;
347 
348 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
349 {
350 	sock_owned_by_me((const struct sock *)msk);
351 }
352 
353 #ifdef CONFIG_DEBUG_NET
354 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
355 #undef tcp_sk
356 #define tcp_sk(ptr) ({								\
357 	typeof(ptr) _ptr = (ptr);						\
358 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
359 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
360 })
361 #define mptcp_sk(ptr) ({						\
362 	typeof(ptr) _ptr = (ptr);					\
363 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
364 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
365 })
366 
367 #else /* !CONFIG_DEBUG_NET */
368 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
369 #endif
370 
371 /* the msk socket don't use the backlog, also account for the bulk
372  * free memory
373  */
374 static inline int __mptcp_rmem(const struct sock *sk)
375 {
376 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
377 }
378 
379 static inline int mptcp_win_from_space(const struct sock *sk, int space)
380 {
381 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
382 }
383 
384 static inline int __mptcp_space(const struct sock *sk)
385 {
386 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
387 }
388 
389 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
390 {
391 	const struct mptcp_sock *msk = mptcp_sk(sk);
392 
393 	return READ_ONCE(msk->first_pending);
394 }
395 
396 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
397 {
398 	struct mptcp_sock *msk = mptcp_sk(sk);
399 	struct mptcp_data_frag *cur;
400 
401 	cur = msk->first_pending;
402 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
403 						     list_next_entry(cur, list);
404 }
405 
406 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
407 {
408 	const struct mptcp_sock *msk = mptcp_sk(sk);
409 
410 	if (!msk->first_pending)
411 		return NULL;
412 
413 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
414 		return NULL;
415 
416 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
417 }
418 
419 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
420 {
421 	struct mptcp_sock *msk = mptcp_sk(sk);
422 
423 	if (msk->snd_una == msk->snd_nxt)
424 		return NULL;
425 
426 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
427 }
428 
429 struct csum_pseudo_header {
430 	__be64 data_seq;
431 	__be32 subflow_seq;
432 	__be16 data_len;
433 	__sum16 csum;
434 };
435 
436 struct mptcp_subflow_request_sock {
437 	struct	tcp_request_sock sk;
438 	u16	mp_capable : 1,
439 		mp_join : 1,
440 		backup : 1,
441 		csum_reqd : 1,
442 		allow_join_id0 : 1;
443 	u8	local_id;
444 	u8	remote_id;
445 	u64	local_key;
446 	u64	idsn;
447 	u32	token;
448 	u32	ssn_offset;
449 	u64	thmac;
450 	u32	local_nonce;
451 	u32	remote_nonce;
452 	struct mptcp_sock	*msk;
453 	struct hlist_nulls_node token_node;
454 };
455 
456 static inline struct mptcp_subflow_request_sock *
457 mptcp_subflow_rsk(const struct request_sock *rsk)
458 {
459 	return (struct mptcp_subflow_request_sock *)rsk;
460 }
461 
462 struct mptcp_delegated_action {
463 	struct napi_struct napi;
464 	struct list_head head;
465 };
466 
467 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
468 
469 #define MPTCP_DELEGATE_SCHEDULED	0
470 #define MPTCP_DELEGATE_SEND		1
471 #define MPTCP_DELEGATE_ACK		2
472 #define MPTCP_DELEGATE_SNDBUF		3
473 
474 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
475 /* MPTCP subflow context */
476 struct mptcp_subflow_context {
477 	struct	list_head node;/* conn_list of subflows */
478 
479 	struct_group(reset,
480 
481 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
482 	u64	local_key;
483 	u64	remote_key;
484 	u64	idsn;
485 	u64	map_seq;
486 	u32	snd_isn;
487 	u32	token;
488 	u32	rel_write_seq;
489 	u32	map_subflow_seq;
490 	u32	ssn_offset;
491 	u32	map_data_len;
492 	__wsum	map_data_csum;
493 	u32	map_csum_len;
494 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
495 		request_join : 1,   /* send MP_JOIN */
496 		request_bkup : 1,
497 		mp_capable : 1,	    /* remote is MPTCP capable */
498 		mp_join : 1,	    /* remote is JOINing */
499 		fully_established : 1,	    /* path validated */
500 		pm_notified : 1,    /* PM hook called for established status */
501 		conn_finished : 1,
502 		map_valid : 1,
503 		map_csum_reqd : 1,
504 		map_data_fin : 1,
505 		mpc_map : 1,
506 		backup : 1,
507 		send_mp_prio : 1,
508 		send_mp_fail : 1,
509 		send_fastclose : 1,
510 		send_infinite_map : 1,
511 		remote_key_valid : 1,        /* received the peer key from */
512 		disposable : 1,	    /* ctx can be free at ulp release time */
513 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
514 		valid_csum_seen : 1,        /* at least one csum validated */
515 		is_mptfo : 1,	    /* subflow is doing TFO */
516 		__unused : 10;
517 	bool	data_avail;
518 	bool	scheduled;
519 	u32	remote_nonce;
520 	u64	thmac;
521 	u32	local_nonce;
522 	u32	remote_token;
523 	union {
524 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
525 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
526 	};
527 	s16	local_id;	    /* if negative not initialized yet */
528 	u8	remote_id;
529 	u8	reset_seen:1;
530 	u8	reset_transient:1;
531 	u8	reset_reason:4;
532 	u8	stale_count;
533 
534 	u32	subflow_id;
535 
536 	long	delegated_status;
537 	unsigned long	fail_tout;
538 
539 	);
540 
541 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
542 
543 	u32	setsockopt_seq;
544 	u32	stale_rcv_tstamp;
545 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
546 				     * protected by the msk socket lock
547 				     */
548 
549 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
550 	struct	sock *conn;	    /* parent mptcp_sock */
551 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
552 	void	(*tcp_state_change)(struct sock *sk);
553 	void	(*tcp_error_report)(struct sock *sk);
554 
555 	struct	rcu_head rcu;
556 };
557 
558 static inline struct mptcp_subflow_context *
559 mptcp_subflow_ctx(const struct sock *sk)
560 {
561 	struct inet_connection_sock *icsk = inet_csk(sk);
562 
563 	/* Use RCU on icsk_ulp_data only for sock diag code */
564 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
565 }
566 
567 static inline struct sock *
568 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
569 {
570 	return subflow->tcp_sock;
571 }
572 
573 static inline void
574 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
575 {
576 	memset(&subflow->reset, 0, sizeof(subflow->reset));
577 	subflow->request_mptcp = 1;
578 	WRITE_ONCE(subflow->local_id, -1);
579 }
580 
581 static inline u64
582 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
583 {
584 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
585 		      subflow->ssn_offset -
586 		      subflow->map_subflow_seq;
587 }
588 
589 static inline u64
590 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
591 {
592 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
593 }
594 
595 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
596 
597 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
598 {
599 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
600 	struct mptcp_delegated_action *delegated;
601 	bool schedule;
602 
603 	/* the caller held the subflow bh socket lock */
604 	lockdep_assert_in_softirq();
605 
606 	/* The implied barrier pairs with tcp_release_cb_override()
607 	 * mptcp_napi_poll(), and ensures the below list check sees list
608 	 * updates done prior to delegated status bits changes
609 	 */
610 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
611 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
612 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
613 			return;
614 
615 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
616 		schedule = list_empty(&delegated->head);
617 		list_add_tail(&subflow->delegated_node, &delegated->head);
618 		sock_hold(mptcp_subflow_tcp_sock(subflow));
619 		if (schedule)
620 			napi_schedule(&delegated->napi);
621 	}
622 }
623 
624 static inline struct mptcp_subflow_context *
625 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
626 {
627 	struct mptcp_subflow_context *ret;
628 
629 	if (list_empty(&delegated->head))
630 		return NULL;
631 
632 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
633 	list_del_init(&ret->delegated_node);
634 	return ret;
635 }
636 
637 int mptcp_is_enabled(const struct net *net);
638 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
639 int mptcp_is_checksum_enabled(const struct net *net);
640 int mptcp_allow_join_id0(const struct net *net);
641 unsigned int mptcp_stale_loss_cnt(const struct net *net);
642 unsigned int mptcp_close_timeout(const struct sock *sk);
643 int mptcp_get_pm_type(const struct net *net);
644 const char *mptcp_get_scheduler(const struct net *net);
645 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
646 				       struct mptcp_subflow_context *subflow,
647 				       const struct mptcp_options_received *mp_opt);
648 bool __mptcp_retransmit_pending_data(struct sock *sk);
649 void mptcp_check_and_set_pending(struct sock *sk);
650 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
651 bool mptcp_subflow_data_available(struct sock *sk);
652 void __init mptcp_subflow_init(void);
653 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
654 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
655 		     struct mptcp_subflow_context *subflow);
656 void __mptcp_subflow_send_ack(struct sock *ssk);
657 void mptcp_subflow_reset(struct sock *ssk);
658 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
659 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
660 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
661 bool __mptcp_close(struct sock *sk, long timeout);
662 void mptcp_cancel_work(struct sock *sk);
663 void __mptcp_unaccepted_force_close(struct sock *sk);
664 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
665 void mptcp_set_state(struct sock *sk, int state);
666 
667 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
668 			   const struct mptcp_addr_info *b, bool use_port);
669 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
670 
671 /* called with sk socket lock held */
672 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
673 			    const struct mptcp_addr_info *remote);
674 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
675 				struct socket **new_sock);
676 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
677 			 struct sockaddr_storage *addr,
678 			 unsigned short family);
679 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
680 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
681 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
682 void mptcp_sched_init(void);
683 int mptcp_init_sched(struct mptcp_sock *msk,
684 		     struct mptcp_sched_ops *sched);
685 void mptcp_release_sched(struct mptcp_sock *msk);
686 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
687 				 bool scheduled);
688 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
689 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
690 int mptcp_sched_get_send(struct mptcp_sock *msk);
691 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
692 
693 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
694 {
695 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
696 }
697 
698 static inline bool mptcp_epollin_ready(const struct sock *sk)
699 {
700 	/* mptcp doesn't have to deal with small skbs in the receive queue,
701 	 * at it can always coalesce them
702 	 */
703 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
704 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
705 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
706 	       READ_ONCE(tcp_memory_pressure);
707 }
708 
709 int mptcp_set_rcvlowat(struct sock *sk, int val);
710 
711 static inline bool __tcp_can_send(const struct sock *ssk)
712 {
713 	/* only send if our side has not closed yet */
714 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
715 }
716 
717 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
718 {
719 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
720 	if (subflow->request_join && !subflow->fully_established)
721 		return false;
722 
723 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
724 }
725 
726 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
727 
728 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
729 
730 void mptcp_subflow_drop_ctx(struct sock *ssk);
731 
732 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
733 					      struct mptcp_subflow_context *ctx)
734 {
735 	sk->sk_data_ready = sock_def_readable;
736 	sk->sk_state_change = ctx->tcp_state_change;
737 	sk->sk_write_space = sk_stream_write_space;
738 	sk->sk_error_report = ctx->tcp_error_report;
739 
740 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
741 }
742 
743 void __init mptcp_proto_init(void);
744 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
745 int __init mptcp_proto_v6_init(void);
746 #endif
747 
748 struct sock *mptcp_sk_clone_init(const struct sock *sk,
749 				 const struct mptcp_options_received *mp_opt,
750 				 struct sock *ssk,
751 				 struct request_sock *req);
752 void mptcp_get_options(const struct sk_buff *skb,
753 		       struct mptcp_options_received *mp_opt);
754 
755 void mptcp_finish_connect(struct sock *sk);
756 void __mptcp_sync_state(struct sock *sk, int state);
757 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
758 
759 static inline void mptcp_stop_tout_timer(struct sock *sk)
760 {
761 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
762 		return;
763 
764 	sk_stop_timer(sk, &sk->sk_timer);
765 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
766 }
767 
768 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
769 {
770 	/* avoid 0 timestamp, as that means no close timeout */
771 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
772 }
773 
774 static inline void mptcp_start_tout_timer(struct sock *sk)
775 {
776 	mptcp_set_close_tout(sk, tcp_jiffies32);
777 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
778 }
779 
780 static inline bool mptcp_is_fully_established(struct sock *sk)
781 {
782 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
783 	       READ_ONCE(mptcp_sk(sk)->fully_established);
784 }
785 
786 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
787 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
788 bool mptcp_finish_join(struct sock *sk);
789 bool mptcp_schedule_work(struct sock *sk);
790 int mptcp_setsockopt(struct sock *sk, int level, int optname,
791 		     sockptr_t optval, unsigned int optlen);
792 int mptcp_getsockopt(struct sock *sk, int level, int optname,
793 		     char __user *optval, int __user *option);
794 
795 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
796 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
797 {
798 	if (use_64bit)
799 		return cur_seq;
800 
801 	return __mptcp_expand_seq(old_seq, cur_seq);
802 }
803 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
804 void __mptcp_data_acked(struct sock *sk);
805 void __mptcp_error_report(struct sock *sk);
806 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
807 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
808 {
809 	return READ_ONCE(msk->snd_data_fin_enable) &&
810 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
811 }
812 
813 static inline u32 mptcp_notsent_lowat(const struct sock *sk)
814 {
815 	struct net *net = sock_net(sk);
816 	u32 val;
817 
818 	val = READ_ONCE(mptcp_sk(sk)->notsent_lowat);
819 	return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
820 }
821 
822 static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake)
823 {
824 	const struct mptcp_sock *msk = mptcp_sk(sk);
825 	u32 notsent_bytes;
826 
827 	notsent_bytes = READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt);
828 	return (notsent_bytes << wake) < mptcp_notsent_lowat(sk);
829 }
830 
831 static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake)
832 {
833 	return mptcp_stream_memory_free(sk, wake) &&
834 	       __sk_stream_is_writeable(sk, wake);
835 }
836 
837 static inline void mptcp_write_space(struct sock *sk)
838 {
839 	/* pairs with memory barrier in mptcp_poll */
840 	smp_mb();
841 	if (mptcp_stream_memory_free(sk, 1))
842 		sk_stream_write_space(sk);
843 }
844 
845 static inline void __mptcp_sync_sndbuf(struct sock *sk)
846 {
847 	struct mptcp_subflow_context *subflow;
848 	int ssk_sndbuf, new_sndbuf;
849 
850 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
851 		return;
852 
853 	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
854 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
855 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
856 
857 		subflow->cached_sndbuf = ssk_sndbuf;
858 		new_sndbuf += ssk_sndbuf;
859 	}
860 
861 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
862 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
863 	mptcp_write_space(sk);
864 }
865 
866 /* The called held both the msk socket and the subflow socket locks,
867  * possibly under BH
868  */
869 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
870 {
871 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
872 
873 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
874 		__mptcp_sync_sndbuf(sk);
875 }
876 
877 /* the caller held only the subflow socket lock, either in process or
878  * BH context. Additionally this can be called under the msk data lock,
879  * so we can't acquire such lock here: let the delegate action acquires
880  * the needed locks in suitable order.
881  */
882 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
883 {
884 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
885 
886 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
887 		return;
888 
889 	local_bh_disable();
890 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
891 	local_bh_enable();
892 }
893 
894 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
895 
896 #define MPTCP_TOKEN_MAX_RETRIES	4
897 
898 void __init mptcp_token_init(void);
899 static inline void mptcp_token_init_request(struct request_sock *req)
900 {
901 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
902 }
903 
904 int mptcp_token_new_request(struct request_sock *req);
905 void mptcp_token_destroy_request(struct request_sock *req);
906 int mptcp_token_new_connect(struct sock *ssk);
907 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
908 			struct mptcp_sock *msk);
909 bool mptcp_token_exists(u32 token);
910 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
911 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
912 					 long *s_num);
913 void mptcp_token_destroy(struct mptcp_sock *msk);
914 
915 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
916 
917 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
918 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
919 
920 void __init mptcp_pm_init(void);
921 void mptcp_pm_data_init(struct mptcp_sock *msk);
922 void mptcp_pm_data_reset(struct mptcp_sock *msk);
923 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
924 			struct mptcp_addr_info *addr);
925 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
926 			 bool require_family,
927 			 struct mptcp_pm_addr_entry *entry);
928 bool mptcp_pm_addr_families_match(const struct sock *sk,
929 				  const struct mptcp_addr_info *loc,
930 				  const struct mptcp_addr_info *rem);
931 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
932 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
933 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
934 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
935 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
936 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
937 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
938 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
939 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
940 				 const struct mptcp_subflow_context *subflow);
941 void mptcp_pm_add_addr_received(const struct sock *ssk,
942 				const struct mptcp_addr_info *addr);
943 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
944 			      const struct mptcp_addr_info *addr);
945 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
946 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
947 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
948 			       const struct mptcp_rm_list *rm_list);
949 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
950 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
951 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
952 				 struct mptcp_addr_info *addr,
953 				 struct mptcp_addr_info *rem,
954 				 u8 bkup);
955 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
956 			      const struct mptcp_addr_info *addr);
957 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
958 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
959 struct mptcp_pm_add_entry *
960 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
961 		       const struct mptcp_addr_info *addr, bool check_id);
962 struct mptcp_pm_add_entry *
963 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
964 				const struct mptcp_addr_info *addr);
965 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
966 					 unsigned int id,
967 					 u8 *flags, int *ifindex);
968 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
969 					    u8 *flags, int *ifindex);
970 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
971 						   unsigned int id,
972 						   u8 *flags, int *ifindex);
973 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
974 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
975 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
976 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
977 			   const struct mptcp_addr_info *addr,
978 			   bool echo);
979 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
980 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
981 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
982 
983 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
984 
985 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
986 		 const struct sock *ssk, gfp_t gfp);
987 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
988 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
989 void mptcp_event_pm_listener(const struct sock *ssk,
990 			     enum mptcp_event_type event);
991 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
992 
993 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
994 				     const struct mptcp_options_received *mp_opt);
995 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
996 					      struct request_sock *req);
997 int mptcp_nl_fill_addr(struct sk_buff *skb,
998 		       struct mptcp_pm_addr_entry *entry);
999 
1000 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
1001 {
1002 	return READ_ONCE(msk->pm.addr_signal) &
1003 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
1004 }
1005 
1006 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
1007 {
1008 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
1009 }
1010 
1011 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
1012 {
1013 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
1014 }
1015 
1016 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
1017 {
1018 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
1019 }
1020 
1021 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1022 {
1023 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1024 }
1025 
1026 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1027 {
1028 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1029 }
1030 
1031 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1032 {
1033 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1034 
1035 	if (family == AF_INET6)
1036 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1037 	if (!echo)
1038 		len += MPTCPOPT_THMAC_LEN;
1039 	/* account for 2 trailing 'nop' options */
1040 	if (port)
1041 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1042 
1043 	return len;
1044 }
1045 
1046 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1047 {
1048 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1049 		return -EINVAL;
1050 
1051 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1052 }
1053 
1054 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1055 			      unsigned int opt_size, unsigned int remaining,
1056 			      struct mptcp_addr_info *addr, bool *echo,
1057 			      bool *drop_other_suboptions);
1058 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1059 			     struct mptcp_rm_list *rm_list);
1060 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1061 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1062 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1063 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
1064 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1065 			  struct netlink_callback *cb);
1066 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
1067 				 struct netlink_callback *cb);
1068 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info);
1069 int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info);
1070 int mptcp_userspace_pm_get_addr(struct sk_buff *skb,
1071 				struct genl_info *info);
1072 
1073 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1074 {
1075 	int local_id = READ_ONCE(subflow->local_id);
1076 
1077 	if (local_id < 0)
1078 		return 0;
1079 	return local_id;
1080 }
1081 
1082 void __init mptcp_pm_nl_init(void);
1083 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1084 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1085 				     const struct mptcp_rm_list *rm_list);
1086 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1087 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1088 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1089 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1090 
1091 /* called under PM lock */
1092 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1093 {
1094 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1095 		WRITE_ONCE(msk->pm.accept_subflow, true);
1096 }
1097 
1098 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1099 {
1100 	spin_lock_bh(&msk->pm.lock);
1101 	__mptcp_pm_close_subflow(msk);
1102 	spin_unlock_bh(&msk->pm.lock);
1103 }
1104 
1105 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1106 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1107 
1108 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1109 {
1110 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1111 }
1112 
1113 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1114 
1115 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1116 {
1117 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1118 }
1119 
1120 static inline bool mptcp_check_fallback(const struct sock *sk)
1121 {
1122 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1123 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1124 
1125 	return __mptcp_check_fallback(msk);
1126 }
1127 
1128 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1129 {
1130 	if (__mptcp_check_fallback(msk)) {
1131 		pr_debug("TCP fallback already done (msk=%p)", msk);
1132 		return;
1133 	}
1134 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1135 }
1136 
1137 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1138 {
1139 	struct sock *ssk = READ_ONCE(msk->first);
1140 
1141 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1142 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1143 			TCPF_SYN_RECV | TCPF_LISTEN));
1144 }
1145 
1146 static inline void mptcp_do_fallback(struct sock *ssk)
1147 {
1148 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1149 	struct sock *sk = subflow->conn;
1150 	struct mptcp_sock *msk;
1151 
1152 	msk = mptcp_sk(sk);
1153 	__mptcp_do_fallback(msk);
1154 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1155 		gfp_t saved_allocation = ssk->sk_allocation;
1156 
1157 		/* we are in a atomic (BH) scope, override ssk default for data
1158 		 * fin allocation
1159 		 */
1160 		ssk->sk_allocation = GFP_ATOMIC;
1161 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1162 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1163 		ssk->sk_allocation = saved_allocation;
1164 	}
1165 }
1166 
1167 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1168 
1169 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1170 {
1171 	struct mptcp_ext *mpext;
1172 
1173 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1174 	if (mpext && mpext->infinite_map)
1175 		return true;
1176 
1177 	return false;
1178 }
1179 
1180 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1181 {
1182 	return (subflow->request_mptcp || subflow->request_join);
1183 }
1184 
1185 static inline bool subflow_simultaneous_connect(struct sock *sk)
1186 {
1187 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1188 
1189 	return (1 << sk->sk_state) &
1190 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1191 	       is_active_ssk(subflow) &&
1192 	       !subflow->conn_finished;
1193 }
1194 
1195 #ifdef CONFIG_SYN_COOKIES
1196 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1197 				       struct sk_buff *skb);
1198 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1199 					struct sk_buff *skb);
1200 void __init mptcp_join_cookie_init(void);
1201 #else
1202 static inline void
1203 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1204 				  struct sk_buff *skb) {}
1205 static inline bool
1206 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1207 				   struct sk_buff *skb)
1208 {
1209 	return false;
1210 }
1211 
1212 static inline void mptcp_join_cookie_init(void) {}
1213 #endif
1214 
1215 #endif /* __MPTCP_PROTOCOL_H */
1216