xref: /linux/net/mptcp/protocol.h (revision 9112fc0109fc0037ac3b8b633a169e78b4e23ca1)
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 #ifdef CONFIG_DEBUG_NET
352 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
353 #undef tcp_sk
354 #define tcp_sk(ptr) ({								\
355 	typeof(ptr) _ptr = (ptr);						\
356 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
357 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
358 })
359 #define mptcp_sk(ptr) ({						\
360 	typeof(ptr) _ptr = (ptr);					\
361 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
362 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
363 })
364 
365 #else /* !CONFIG_DEBUG_NET */
366 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
367 #endif
368 
369 /* the msk socket don't use the backlog, also account for the bulk
370  * free memory
371  */
372 static inline int __mptcp_rmem(const struct sock *sk)
373 {
374 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
375 }
376 
377 static inline int mptcp_win_from_space(const struct sock *sk, int space)
378 {
379 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
380 }
381 
382 static inline int __mptcp_space(const struct sock *sk)
383 {
384 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
385 }
386 
387 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
388 {
389 	const struct mptcp_sock *msk = mptcp_sk(sk);
390 
391 	return READ_ONCE(msk->first_pending);
392 }
393 
394 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
395 {
396 	struct mptcp_sock *msk = mptcp_sk(sk);
397 	struct mptcp_data_frag *cur;
398 
399 	cur = msk->first_pending;
400 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
401 						     list_next_entry(cur, list);
402 }
403 
404 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
405 {
406 	const struct mptcp_sock *msk = mptcp_sk(sk);
407 
408 	if (!msk->first_pending)
409 		return NULL;
410 
411 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
412 		return NULL;
413 
414 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
415 }
416 
417 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
418 {
419 	struct mptcp_sock *msk = mptcp_sk(sk);
420 
421 	if (msk->snd_una == msk->snd_nxt)
422 		return NULL;
423 
424 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
425 }
426 
427 struct csum_pseudo_header {
428 	__be64 data_seq;
429 	__be32 subflow_seq;
430 	__be16 data_len;
431 	__sum16 csum;
432 };
433 
434 struct mptcp_subflow_request_sock {
435 	struct	tcp_request_sock sk;
436 	u16	mp_capable : 1,
437 		mp_join : 1,
438 		backup : 1,
439 		csum_reqd : 1,
440 		allow_join_id0 : 1;
441 	u8	local_id;
442 	u8	remote_id;
443 	u64	local_key;
444 	u64	idsn;
445 	u32	token;
446 	u32	ssn_offset;
447 	u64	thmac;
448 	u32	local_nonce;
449 	u32	remote_nonce;
450 	struct mptcp_sock	*msk;
451 	struct hlist_nulls_node token_node;
452 };
453 
454 static inline struct mptcp_subflow_request_sock *
455 mptcp_subflow_rsk(const struct request_sock *rsk)
456 {
457 	return (struct mptcp_subflow_request_sock *)rsk;
458 }
459 
460 struct mptcp_delegated_action {
461 	struct napi_struct napi;
462 	struct list_head head;
463 };
464 
465 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
466 
467 #define MPTCP_DELEGATE_SCHEDULED	0
468 #define MPTCP_DELEGATE_SEND		1
469 #define MPTCP_DELEGATE_ACK		2
470 #define MPTCP_DELEGATE_SNDBUF		3
471 
472 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
473 /* MPTCP subflow context */
474 struct mptcp_subflow_context {
475 	struct	list_head node;/* conn_list of subflows */
476 
477 	struct_group(reset,
478 
479 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
480 	u64	local_key;
481 	u64	remote_key;
482 	u64	idsn;
483 	u64	map_seq;
484 	u32	snd_isn;
485 	u32	token;
486 	u32	rel_write_seq;
487 	u32	map_subflow_seq;
488 	u32	ssn_offset;
489 	u32	map_data_len;
490 	__wsum	map_data_csum;
491 	u32	map_csum_len;
492 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
493 		request_join : 1,   /* send MP_JOIN */
494 		request_bkup : 1,
495 		mp_capable : 1,	    /* remote is MPTCP capable */
496 		mp_join : 1,	    /* remote is JOINing */
497 		fully_established : 1,	    /* path validated */
498 		pm_notified : 1,    /* PM hook called for established status */
499 		conn_finished : 1,
500 		map_valid : 1,
501 		map_csum_reqd : 1,
502 		map_data_fin : 1,
503 		mpc_map : 1,
504 		backup : 1,
505 		send_mp_prio : 1,
506 		send_mp_fail : 1,
507 		send_fastclose : 1,
508 		send_infinite_map : 1,
509 		remote_key_valid : 1,        /* received the peer key from */
510 		disposable : 1,	    /* ctx can be free at ulp release time */
511 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
512 		valid_csum_seen : 1,        /* at least one csum validated */
513 		is_mptfo : 1,	    /* subflow is doing TFO */
514 		__unused : 10;
515 	bool	data_avail;
516 	bool	scheduled;
517 	u32	remote_nonce;
518 	u64	thmac;
519 	u32	local_nonce;
520 	u32	remote_token;
521 	union {
522 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
523 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
524 	};
525 	s16	local_id;	    /* if negative not initialized yet */
526 	u8	remote_id;
527 	u8	reset_seen:1;
528 	u8	reset_transient:1;
529 	u8	reset_reason:4;
530 	u8	stale_count;
531 
532 	u32	subflow_id;
533 
534 	long	delegated_status;
535 	unsigned long	fail_tout;
536 
537 	);
538 
539 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
540 
541 	u32	setsockopt_seq;
542 	u32	stale_rcv_tstamp;
543 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
544 				     * protected by the msk socket lock
545 				     */
546 
547 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
548 	struct	sock *conn;	    /* parent mptcp_sock */
549 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
550 	void	(*tcp_state_change)(struct sock *sk);
551 	void	(*tcp_error_report)(struct sock *sk);
552 
553 	struct	rcu_head rcu;
554 };
555 
556 static inline struct mptcp_subflow_context *
557 mptcp_subflow_ctx(const struct sock *sk)
558 {
559 	struct inet_connection_sock *icsk = inet_csk(sk);
560 
561 	/* Use RCU on icsk_ulp_data only for sock diag code */
562 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
563 }
564 
565 static inline struct sock *
566 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
567 {
568 	return subflow->tcp_sock;
569 }
570 
571 static inline void
572 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
573 {
574 	memset(&subflow->reset, 0, sizeof(subflow->reset));
575 	subflow->request_mptcp = 1;
576 	WRITE_ONCE(subflow->local_id, -1);
577 }
578 
579 static inline u64
580 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
581 {
582 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
583 		      subflow->ssn_offset -
584 		      subflow->map_subflow_seq;
585 }
586 
587 static inline u64
588 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
589 {
590 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
591 }
592 
593 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
594 
595 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
596 {
597 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
598 	struct mptcp_delegated_action *delegated;
599 	bool schedule;
600 
601 	/* the caller held the subflow bh socket lock */
602 	lockdep_assert_in_softirq();
603 
604 	/* The implied barrier pairs with tcp_release_cb_override()
605 	 * mptcp_napi_poll(), and ensures the below list check sees list
606 	 * updates done prior to delegated status bits changes
607 	 */
608 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
609 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
610 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
611 			return;
612 
613 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
614 		schedule = list_empty(&delegated->head);
615 		list_add_tail(&subflow->delegated_node, &delegated->head);
616 		sock_hold(mptcp_subflow_tcp_sock(subflow));
617 		if (schedule)
618 			napi_schedule(&delegated->napi);
619 	}
620 }
621 
622 static inline struct mptcp_subflow_context *
623 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
624 {
625 	struct mptcp_subflow_context *ret;
626 
627 	if (list_empty(&delegated->head))
628 		return NULL;
629 
630 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
631 	list_del_init(&ret->delegated_node);
632 	return ret;
633 }
634 
635 int mptcp_is_enabled(const struct net *net);
636 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
637 int mptcp_is_checksum_enabled(const struct net *net);
638 int mptcp_allow_join_id0(const struct net *net);
639 unsigned int mptcp_stale_loss_cnt(const struct net *net);
640 unsigned int mptcp_close_timeout(const struct sock *sk);
641 int mptcp_get_pm_type(const struct net *net);
642 const char *mptcp_get_scheduler(const struct net *net);
643 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
644 				       struct mptcp_subflow_context *subflow,
645 				       const struct mptcp_options_received *mp_opt);
646 bool __mptcp_retransmit_pending_data(struct sock *sk);
647 void mptcp_check_and_set_pending(struct sock *sk);
648 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
649 bool mptcp_subflow_data_available(struct sock *sk);
650 void __init mptcp_subflow_init(void);
651 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
652 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
653 		     struct mptcp_subflow_context *subflow);
654 void __mptcp_subflow_send_ack(struct sock *ssk);
655 void mptcp_subflow_reset(struct sock *ssk);
656 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
657 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
658 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
659 bool __mptcp_close(struct sock *sk, long timeout);
660 void mptcp_cancel_work(struct sock *sk);
661 void __mptcp_unaccepted_force_close(struct sock *sk);
662 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
663 void mptcp_set_state(struct sock *sk, int state);
664 
665 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
666 			   const struct mptcp_addr_info *b, bool use_port);
667 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
668 
669 /* called with sk socket lock held */
670 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
671 			    const struct mptcp_addr_info *remote);
672 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
673 				struct socket **new_sock);
674 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
675 			 struct sockaddr_storage *addr,
676 			 unsigned short family);
677 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
678 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
679 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
680 void mptcp_sched_init(void);
681 int mptcp_init_sched(struct mptcp_sock *msk,
682 		     struct mptcp_sched_ops *sched);
683 void mptcp_release_sched(struct mptcp_sock *msk);
684 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
685 				 bool scheduled);
686 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
687 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
688 int mptcp_sched_get_send(struct mptcp_sock *msk);
689 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
690 
691 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
692 {
693 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
694 }
695 
696 static inline bool mptcp_epollin_ready(const struct sock *sk)
697 {
698 	/* mptcp doesn't have to deal with small skbs in the receive queue,
699 	 * at it can always coalesce them
700 	 */
701 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
702 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
703 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
704 	       READ_ONCE(tcp_memory_pressure);
705 }
706 
707 int mptcp_set_rcvlowat(struct sock *sk, int val);
708 
709 static inline bool __tcp_can_send(const struct sock *ssk)
710 {
711 	/* only send if our side has not closed yet */
712 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
713 }
714 
715 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
716 {
717 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
718 	if (subflow->request_join && !subflow->fully_established)
719 		return false;
720 
721 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
722 }
723 
724 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
725 
726 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
727 
728 void mptcp_subflow_drop_ctx(struct sock *ssk);
729 
730 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
731 					      struct mptcp_subflow_context *ctx)
732 {
733 	sk->sk_data_ready = sock_def_readable;
734 	sk->sk_state_change = ctx->tcp_state_change;
735 	sk->sk_write_space = sk_stream_write_space;
736 	sk->sk_error_report = ctx->tcp_error_report;
737 
738 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
739 }
740 
741 void __init mptcp_proto_init(void);
742 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
743 int __init mptcp_proto_v6_init(void);
744 #endif
745 
746 struct sock *mptcp_sk_clone_init(const struct sock *sk,
747 				 const struct mptcp_options_received *mp_opt,
748 				 struct sock *ssk,
749 				 struct request_sock *req);
750 void mptcp_get_options(const struct sk_buff *skb,
751 		       struct mptcp_options_received *mp_opt);
752 
753 void mptcp_finish_connect(struct sock *sk);
754 void __mptcp_sync_state(struct sock *sk, int state);
755 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
756 
757 static inline void mptcp_stop_tout_timer(struct sock *sk)
758 {
759 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
760 		return;
761 
762 	sk_stop_timer(sk, &sk->sk_timer);
763 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
764 }
765 
766 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
767 {
768 	/* avoid 0 timestamp, as that means no close timeout */
769 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
770 }
771 
772 static inline void mptcp_start_tout_timer(struct sock *sk)
773 {
774 	mptcp_set_close_tout(sk, tcp_jiffies32);
775 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
776 }
777 
778 static inline bool mptcp_is_fully_established(struct sock *sk)
779 {
780 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
781 	       READ_ONCE(mptcp_sk(sk)->fully_established);
782 }
783 
784 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
785 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
786 bool mptcp_finish_join(struct sock *sk);
787 bool mptcp_schedule_work(struct sock *sk);
788 int mptcp_setsockopt(struct sock *sk, int level, int optname,
789 		     sockptr_t optval, unsigned int optlen);
790 int mptcp_getsockopt(struct sock *sk, int level, int optname,
791 		     char __user *optval, int __user *option);
792 
793 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
794 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
795 {
796 	if (use_64bit)
797 		return cur_seq;
798 
799 	return __mptcp_expand_seq(old_seq, cur_seq);
800 }
801 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
802 void __mptcp_data_acked(struct sock *sk);
803 void __mptcp_error_report(struct sock *sk);
804 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
805 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
806 {
807 	return READ_ONCE(msk->snd_data_fin_enable) &&
808 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
809 }
810 
811 static inline void mptcp_write_space(struct sock *sk)
812 {
813 	if (sk_stream_is_writeable(sk)) {
814 		/* pairs with memory barrier in mptcp_poll */
815 		smp_mb();
816 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
817 			sk_stream_write_space(sk);
818 	}
819 }
820 
821 static inline void __mptcp_sync_sndbuf(struct sock *sk)
822 {
823 	struct mptcp_subflow_context *subflow;
824 	int ssk_sndbuf, new_sndbuf;
825 
826 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
827 		return;
828 
829 	new_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[0];
830 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
831 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
832 
833 		subflow->cached_sndbuf = ssk_sndbuf;
834 		new_sndbuf += ssk_sndbuf;
835 	}
836 
837 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
838 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
839 	mptcp_write_space(sk);
840 }
841 
842 /* The called held both the msk socket and the subflow socket locks,
843  * possibly under BH
844  */
845 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
846 {
847 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
848 
849 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
850 		__mptcp_sync_sndbuf(sk);
851 }
852 
853 /* the caller held only the subflow socket lock, either in process or
854  * BH context. Additionally this can be called under the msk data lock,
855  * so we can't acquire such lock here: let the delegate action acquires
856  * the needed locks in suitable order.
857  */
858 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
859 {
860 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
861 
862 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
863 		return;
864 
865 	local_bh_disable();
866 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
867 	local_bh_enable();
868 }
869 
870 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
871 
872 #define MPTCP_TOKEN_MAX_RETRIES	4
873 
874 void __init mptcp_token_init(void);
875 static inline void mptcp_token_init_request(struct request_sock *req)
876 {
877 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
878 }
879 
880 int mptcp_token_new_request(struct request_sock *req);
881 void mptcp_token_destroy_request(struct request_sock *req);
882 int mptcp_token_new_connect(struct sock *ssk);
883 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
884 			struct mptcp_sock *msk);
885 bool mptcp_token_exists(u32 token);
886 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
887 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
888 					 long *s_num);
889 void mptcp_token_destroy(struct mptcp_sock *msk);
890 
891 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
892 
893 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
894 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
895 
896 void __init mptcp_pm_init(void);
897 void mptcp_pm_data_init(struct mptcp_sock *msk);
898 void mptcp_pm_data_reset(struct mptcp_sock *msk);
899 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
900 			struct mptcp_addr_info *addr);
901 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
902 			 bool require_family,
903 			 struct mptcp_pm_addr_entry *entry);
904 bool mptcp_pm_addr_families_match(const struct sock *sk,
905 				  const struct mptcp_addr_info *loc,
906 				  const struct mptcp_addr_info *rem);
907 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
908 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
909 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
910 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
911 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
912 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
913 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
914 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
915 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
916 				 const struct mptcp_subflow_context *subflow);
917 void mptcp_pm_add_addr_received(const struct sock *ssk,
918 				const struct mptcp_addr_info *addr);
919 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
920 			      const struct mptcp_addr_info *addr);
921 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
922 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
923 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
924 			       const struct mptcp_rm_list *rm_list);
925 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
926 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
927 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
928 				 struct mptcp_addr_info *addr,
929 				 struct mptcp_addr_info *rem,
930 				 u8 bkup);
931 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
932 			      const struct mptcp_addr_info *addr);
933 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
934 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
935 struct mptcp_pm_add_entry *
936 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
937 		       const struct mptcp_addr_info *addr, bool check_id);
938 struct mptcp_pm_add_entry *
939 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
940 				const struct mptcp_addr_info *addr);
941 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
942 					 unsigned int id,
943 					 u8 *flags, int *ifindex);
944 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
945 					    u8 *flags, int *ifindex);
946 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
947 						   unsigned int id,
948 						   u8 *flags, int *ifindex);
949 int mptcp_pm_set_flags(struct net *net, struct nlattr *token,
950 		       struct mptcp_pm_addr_entry *loc,
951 		       struct mptcp_pm_addr_entry *rem, u8 bkup);
952 int mptcp_pm_nl_set_flags(struct net *net, struct mptcp_pm_addr_entry *addr, u8 bkup);
953 int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
954 				 struct mptcp_pm_addr_entry *loc,
955 				 struct mptcp_pm_addr_entry *rem, u8 bkup);
956 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
957 			   const struct mptcp_addr_info *addr,
958 			   bool echo);
959 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
960 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
961 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
962 void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
963 					struct list_head *rm_list);
964 
965 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
966 
967 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
968 		 const struct sock *ssk, gfp_t gfp);
969 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
970 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
971 void mptcp_event_pm_listener(const struct sock *ssk,
972 			     enum mptcp_event_type event);
973 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
974 
975 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
976 				     const struct mptcp_options_received *mp_opt);
977 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
978 					      struct request_sock *req);
979 
980 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
981 {
982 	return READ_ONCE(msk->pm.addr_signal) &
983 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
984 }
985 
986 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
987 {
988 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
989 }
990 
991 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
992 {
993 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
994 }
995 
996 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
997 {
998 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
999 }
1000 
1001 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1002 {
1003 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1004 }
1005 
1006 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1007 {
1008 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1009 }
1010 
1011 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1012 {
1013 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1014 
1015 	if (family == AF_INET6)
1016 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1017 	if (!echo)
1018 		len += MPTCPOPT_THMAC_LEN;
1019 	/* account for 2 trailing 'nop' options */
1020 	if (port)
1021 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1022 
1023 	return len;
1024 }
1025 
1026 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1027 {
1028 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1029 		return -EINVAL;
1030 
1031 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1032 }
1033 
1034 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1035 			      unsigned int opt_size, unsigned int remaining,
1036 			      struct mptcp_addr_info *addr, bool *echo,
1037 			      bool *drop_other_suboptions);
1038 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1039 			     struct mptcp_rm_list *rm_list);
1040 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1041 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1042 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1043 
1044 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1045 {
1046 	int local_id = READ_ONCE(subflow->local_id);
1047 
1048 	if (local_id < 0)
1049 		return 0;
1050 	return local_id;
1051 }
1052 
1053 void __init mptcp_pm_nl_init(void);
1054 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1055 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1056 				     const struct mptcp_rm_list *rm_list);
1057 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1058 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1059 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1060 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1061 
1062 /* called under PM lock */
1063 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1064 {
1065 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1066 		WRITE_ONCE(msk->pm.accept_subflow, true);
1067 }
1068 
1069 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1070 {
1071 	spin_lock_bh(&msk->pm.lock);
1072 	__mptcp_pm_close_subflow(msk);
1073 	spin_unlock_bh(&msk->pm.lock);
1074 }
1075 
1076 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1077 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1078 
1079 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1080 {
1081 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1082 }
1083 
1084 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1085 
1086 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1087 {
1088 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1089 }
1090 
1091 static inline bool mptcp_check_fallback(const struct sock *sk)
1092 {
1093 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1094 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1095 
1096 	return __mptcp_check_fallback(msk);
1097 }
1098 
1099 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1100 {
1101 	if (__mptcp_check_fallback(msk)) {
1102 		pr_debug("TCP fallback already done (msk=%p)", msk);
1103 		return;
1104 	}
1105 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1106 }
1107 
1108 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1109 {
1110 	struct sock *ssk = READ_ONCE(msk->first);
1111 
1112 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1113 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1114 			TCPF_SYN_RECV | TCPF_LISTEN));
1115 }
1116 
1117 static inline void mptcp_do_fallback(struct sock *ssk)
1118 {
1119 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1120 	struct sock *sk = subflow->conn;
1121 	struct mptcp_sock *msk;
1122 
1123 	msk = mptcp_sk(sk);
1124 	__mptcp_do_fallback(msk);
1125 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1126 		gfp_t saved_allocation = ssk->sk_allocation;
1127 
1128 		/* we are in a atomic (BH) scope, override ssk default for data
1129 		 * fin allocation
1130 		 */
1131 		ssk->sk_allocation = GFP_ATOMIC;
1132 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1133 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1134 		ssk->sk_allocation = saved_allocation;
1135 	}
1136 }
1137 
1138 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1139 
1140 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1141 {
1142 	struct mptcp_ext *mpext;
1143 
1144 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1145 	if (mpext && mpext->infinite_map)
1146 		return true;
1147 
1148 	return false;
1149 }
1150 
1151 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1152 {
1153 	return (subflow->request_mptcp || subflow->request_join);
1154 }
1155 
1156 static inline bool subflow_simultaneous_connect(struct sock *sk)
1157 {
1158 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1159 
1160 	return (1 << sk->sk_state) &
1161 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1162 	       is_active_ssk(subflow) &&
1163 	       !subflow->conn_finished;
1164 }
1165 
1166 #ifdef CONFIG_SYN_COOKIES
1167 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1168 				       struct sk_buff *skb);
1169 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1170 					struct sk_buff *skb);
1171 void __init mptcp_join_cookie_init(void);
1172 #else
1173 static inline void
1174 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1175 				  struct sk_buff *skb) {}
1176 static inline bool
1177 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1178 				   struct sk_buff *skb)
1179 {
1180 	return false;
1181 }
1182 
1183 static inline void mptcp_join_cookie_init(void) {}
1184 #endif
1185 
1186 #endif /* __MPTCP_PROTOCOL_H */
1187