xref: /linux/net/mptcp/protocol.h (revision c0ead5552c0fcc15d907651f6d6a8084d32689b3)
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 
14 #define MPTCP_SUPPORTED_VERSION	1
15 
16 /* MPTCP option bits */
17 #define OPTION_MPTCP_MPC_SYN	BIT(0)
18 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
19 #define OPTION_MPTCP_MPC_ACK	BIT(2)
20 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
21 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
22 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
23 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
24 #define OPTION_MPTCP_ADD_ADDR6	BIT(7)
25 #define OPTION_MPTCP_RM_ADDR	BIT(8)
26 
27 /* MPTCP option subtypes */
28 #define MPTCPOPT_MP_CAPABLE	0
29 #define MPTCPOPT_MP_JOIN	1
30 #define MPTCPOPT_DSS		2
31 #define MPTCPOPT_ADD_ADDR	3
32 #define MPTCPOPT_RM_ADDR	4
33 #define MPTCPOPT_MP_PRIO	5
34 #define MPTCPOPT_MP_FAIL	6
35 #define MPTCPOPT_MP_FASTCLOSE	7
36 
37 /* MPTCP suboption lengths */
38 #define TCPOLEN_MPTCP_MPC_SYN		4
39 #define TCPOLEN_MPTCP_MPC_SYNACK	12
40 #define TCPOLEN_MPTCP_MPC_ACK		20
41 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
42 #define TCPOLEN_MPTCP_MPJ_SYN		12
43 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
44 #define TCPOLEN_MPTCP_MPJ_ACK		24
45 #define TCPOLEN_MPTCP_DSS_BASE		4
46 #define TCPOLEN_MPTCP_DSS_ACK32		4
47 #define TCPOLEN_MPTCP_DSS_ACK64		8
48 #define TCPOLEN_MPTCP_DSS_MAP32		10
49 #define TCPOLEN_MPTCP_DSS_MAP64		14
50 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
51 #define TCPOLEN_MPTCP_ADD_ADDR		16
52 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	20
53 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
54 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	12
55 #define TCPOLEN_MPTCP_ADD_ADDR6		28
56 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	32
57 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
58 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	24
59 #define TCPOLEN_MPTCP_PORT_LEN		4
60 #define TCPOLEN_MPTCP_RM_ADDR_BASE	4
61 
62 /* MPTCP MP_JOIN flags */
63 #define MPTCPOPT_BACKUP		BIT(0)
64 #define MPTCPOPT_HMAC_LEN	20
65 #define MPTCPOPT_THMAC_LEN	8
66 
67 /* MPTCP MP_CAPABLE flags */
68 #define MPTCP_VERSION_MASK	(0x0F)
69 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
70 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
71 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
72 #define MPTCP_CAP_FLAG_MASK	(0x3F)
73 
74 /* MPTCP DSS flags */
75 #define MPTCP_DSS_DATA_FIN	BIT(4)
76 #define MPTCP_DSS_DSN64		BIT(3)
77 #define MPTCP_DSS_HAS_MAP	BIT(2)
78 #define MPTCP_DSS_ACK64		BIT(1)
79 #define MPTCP_DSS_HAS_ACK	BIT(0)
80 #define MPTCP_DSS_FLAG_MASK	(0x1F)
81 
82 /* MPTCP ADD_ADDR flags */
83 #define MPTCP_ADDR_ECHO		BIT(0)
84 #define MPTCP_ADDR_IPVERSION_4	4
85 #define MPTCP_ADDR_IPVERSION_6	6
86 
87 /* MPTCP socket flags */
88 #define MPTCP_DATA_READY	0
89 #define MPTCP_NOSPACE		1
90 #define MPTCP_WORK_RTX		2
91 #define MPTCP_WORK_EOF		3
92 #define MPTCP_FALLBACK_DONE	4
93 #define MPTCP_WORK_CLOSE_SUBFLOW 5
94 #define MPTCP_PUSH_PENDING	6
95 #define MPTCP_CLEAN_UNA		7
96 
97 static inline bool before64(__u64 seq1, __u64 seq2)
98 {
99 	return (__s64)(seq1 - seq2) < 0;
100 }
101 
102 #define after64(seq2, seq1)	before64(seq1, seq2)
103 
104 struct mptcp_options_received {
105 	u64	sndr_key;
106 	u64	rcvr_key;
107 	u64	data_ack;
108 	u64	data_seq;
109 	u32	subflow_seq;
110 	u16	data_len;
111 	u16	mp_capable : 1,
112 		mp_join : 1,
113 		dss : 1,
114 		add_addr : 1,
115 		rm_addr : 1,
116 		family : 4,
117 		echo : 1,
118 		backup : 1;
119 	u32	token;
120 	u32	nonce;
121 	u64	thmac;
122 	u8	hmac[20];
123 	u8	join_id;
124 	u8	use_map:1,
125 		dsn64:1,
126 		data_fin:1,
127 		use_ack:1,
128 		ack64:1,
129 		mpc_map:1,
130 		__unused:2;
131 	u8	addr_id;
132 	u8	rm_id;
133 	union {
134 		struct in_addr	addr;
135 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
136 		struct in6_addr	addr6;
137 #endif
138 	};
139 	u64	ahmac;
140 	u16	port;
141 };
142 
143 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
144 {
145 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
146 		     ((nib & 0xF) << 8) | field);
147 }
148 
149 struct mptcp_addr_info {
150 	sa_family_t		family;
151 	__be16			port;
152 	u8			id;
153 	u8			flags;
154 	int			ifindex;
155 	union {
156 		struct in_addr addr;
157 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
158 		struct in6_addr addr6;
159 #endif
160 	};
161 };
162 
163 enum mptcp_pm_status {
164 	MPTCP_PM_ADD_ADDR_RECEIVED,
165 	MPTCP_PM_ADD_ADDR_SEND_ACK,
166 	MPTCP_PM_RM_ADDR_RECEIVED,
167 	MPTCP_PM_ESTABLISHED,
168 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
169 	MPTCP_PM_SUBFLOW_ESTABLISHED,
170 };
171 
172 enum mptcp_addr_signal_status {
173 	MPTCP_ADD_ADDR_SIGNAL,
174 	MPTCP_ADD_ADDR_ECHO,
175 	MPTCP_ADD_ADDR_IPV6,
176 	MPTCP_ADD_ADDR_PORT,
177 	MPTCP_RM_ADDR_SIGNAL,
178 };
179 
180 struct mptcp_pm_data {
181 	struct mptcp_addr_info local;
182 	struct mptcp_addr_info remote;
183 	struct list_head anno_list;
184 
185 	spinlock_t	lock;		/*protects the whole PM data */
186 
187 	u8		addr_signal;
188 	bool		server_side;
189 	bool		work_pending;
190 	bool		accept_addr;
191 	bool		accept_subflow;
192 	u8		add_addr_signaled;
193 	u8		add_addr_accepted;
194 	u8		local_addr_used;
195 	u8		subflows;
196 	u8		add_addr_signal_max;
197 	u8		add_addr_accept_max;
198 	u8		local_addr_max;
199 	u8		subflows_max;
200 	u8		status;
201 	u8		rm_id;
202 };
203 
204 struct mptcp_data_frag {
205 	struct list_head list;
206 	u64 data_seq;
207 	u16 data_len;
208 	u16 offset;
209 	u16 overhead;
210 	u16 already_sent;
211 	struct page *page;
212 };
213 
214 /* MPTCP connection sock */
215 struct mptcp_sock {
216 	/* inet_connection_sock must be the first member */
217 	struct inet_connection_sock sk;
218 	u64		local_key;
219 	u64		remote_key;
220 	u64		write_seq;
221 	u64		snd_nxt;
222 	u64		ack_seq;
223 	u64		rcv_wnd_sent;
224 	u64		rcv_data_fin_seq;
225 	int		wmem_reserved;
226 	struct sock	*last_snd;
227 	int		snd_burst;
228 	int		old_wspace;
229 	u64		snd_una;
230 	u64		wnd_end;
231 	unsigned long	timer_ival;
232 	u32		token;
233 	int		rmem_pending;
234 	int		rmem_released;
235 	unsigned long	flags;
236 	bool		can_ack;
237 	bool		fully_established;
238 	bool		rcv_data_fin;
239 	bool		snd_data_fin_enable;
240 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
241 	spinlock_t	join_list_lock;
242 	struct sock	*ack_hint;
243 	struct work_struct work;
244 	struct sk_buff  *ooo_last_skb;
245 	struct rb_root  out_of_order_queue;
246 	struct sk_buff_head receive_queue;
247 	struct sk_buff_head skb_tx_cache;	/* this is wmem accounted */
248 	int		tx_pending_data;
249 	int		size_goal_cache;
250 	struct list_head conn_list;
251 	struct list_head rtx_queue;
252 	struct mptcp_data_frag *first_pending;
253 	struct list_head join_list;
254 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
255 	struct sock	*first;
256 	struct mptcp_pm_data	pm;
257 	struct {
258 		u32	space;	/* bytes copied in last measurement window */
259 		u32	copied; /* bytes copied in this measurement window */
260 		u64	time;	/* start time of measurement window */
261 		u64	rtt_us; /* last maximum rtt of subflows */
262 	} rcvq_space;
263 };
264 
265 #define mptcp_lock_sock(___sk, cb) do {					\
266 	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
267 	might_sleep();							\
268 	spin_lock_bh(&__sk->sk_lock.slock);				\
269 	if (__sk->sk_lock.owned)					\
270 		__lock_sock(__sk);					\
271 	cb;								\
272 	__sk->sk_lock.owned = 1;					\
273 	spin_unlock(&__sk->sk_lock.slock);				\
274 	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
275 	local_bh_enable();						\
276 } while (0)
277 
278 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
279 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
280 
281 #define mptcp_for_each_subflow(__msk, __subflow)			\
282 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
283 
284 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
285 {
286 	return (struct mptcp_sock *)sk;
287 }
288 
289 static inline int __mptcp_space(const struct sock *sk)
290 {
291 	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);
292 }
293 
294 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
295 {
296 	const struct mptcp_sock *msk = mptcp_sk(sk);
297 
298 	return READ_ONCE(msk->first_pending);
299 }
300 
301 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
302 {
303 	struct mptcp_sock *msk = mptcp_sk(sk);
304 	struct mptcp_data_frag *cur;
305 
306 	cur = msk->first_pending;
307 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
308 						     list_next_entry(cur, list);
309 }
310 
311 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
312 {
313 	struct mptcp_sock *msk = mptcp_sk(sk);
314 
315 	if (!msk->first_pending)
316 		return NULL;
317 
318 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
319 		return NULL;
320 
321 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
322 }
323 
324 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
325 {
326 	struct mptcp_sock *msk = mptcp_sk(sk);
327 
328 	if (!before64(msk->snd_nxt, READ_ONCE(msk->snd_una)))
329 		return NULL;
330 
331 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
332 }
333 
334 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
335 {
336 	struct mptcp_sock *msk = mptcp_sk(sk);
337 
338 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
339 }
340 
341 struct mptcp_subflow_request_sock {
342 	struct	tcp_request_sock sk;
343 	u16	mp_capable : 1,
344 		mp_join : 1,
345 		backup : 1;
346 	u8	local_id;
347 	u8	remote_id;
348 	u64	local_key;
349 	u64	idsn;
350 	u32	token;
351 	u32	ssn_offset;
352 	u64	thmac;
353 	u32	local_nonce;
354 	u32	remote_nonce;
355 	struct mptcp_sock	*msk;
356 	struct hlist_nulls_node token_node;
357 };
358 
359 static inline struct mptcp_subflow_request_sock *
360 mptcp_subflow_rsk(const struct request_sock *rsk)
361 {
362 	return (struct mptcp_subflow_request_sock *)rsk;
363 }
364 
365 enum mptcp_data_avail {
366 	MPTCP_SUBFLOW_NODATA,
367 	MPTCP_SUBFLOW_DATA_AVAIL,
368 	MPTCP_SUBFLOW_OOO_DATA
369 };
370 
371 /* MPTCP subflow context */
372 struct mptcp_subflow_context {
373 	struct	list_head node;/* conn_list of subflows */
374 	u64	local_key;
375 	u64	remote_key;
376 	u64	idsn;
377 	u64	map_seq;
378 	u32	snd_isn;
379 	u32	token;
380 	u32	rel_write_seq;
381 	u32	map_subflow_seq;
382 	u32	ssn_offset;
383 	u32	map_data_len;
384 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
385 		request_join : 1,   /* send MP_JOIN */
386 		request_bkup : 1,
387 		mp_capable : 1,	    /* remote is MPTCP capable */
388 		mp_join : 1,	    /* remote is JOINing */
389 		fully_established : 1,	    /* path validated */
390 		pm_notified : 1,    /* PM hook called for established status */
391 		conn_finished : 1,
392 		map_valid : 1,
393 		mpc_map : 1,
394 		backup : 1,
395 		rx_eof : 1,
396 		can_ack : 1,        /* only after processing the remote a key */
397 		disposable : 1;	    /* ctx can be free at ulp release time */
398 	enum mptcp_data_avail data_avail;
399 	u32	remote_nonce;
400 	u64	thmac;
401 	u32	local_nonce;
402 	u32	remote_token;
403 	u8	hmac[MPTCPOPT_HMAC_LEN];
404 	u8	local_id;
405 	u8	remote_id;
406 
407 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
408 	struct	sock *conn;	    /* parent mptcp_sock */
409 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
410 	void	(*tcp_data_ready)(struct sock *sk);
411 	void	(*tcp_state_change)(struct sock *sk);
412 	void	(*tcp_write_space)(struct sock *sk);
413 
414 	struct	rcu_head rcu;
415 };
416 
417 static inline struct mptcp_subflow_context *
418 mptcp_subflow_ctx(const struct sock *sk)
419 {
420 	struct inet_connection_sock *icsk = inet_csk(sk);
421 
422 	/* Use RCU on icsk_ulp_data only for sock diag code */
423 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
424 }
425 
426 static inline struct sock *
427 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
428 {
429 	return subflow->tcp_sock;
430 }
431 
432 static inline u64
433 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
434 {
435 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
436 		      subflow->ssn_offset -
437 		      subflow->map_subflow_seq;
438 }
439 
440 static inline u64
441 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
442 {
443 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
444 }
445 
446 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
447 					     struct mptcp_subflow_context *subflow)
448 {
449 	sock_hold(mptcp_subflow_tcp_sock(subflow));
450 	spin_lock_bh(&msk->join_list_lock);
451 	list_add_tail(&subflow->node, &msk->join_list);
452 	spin_unlock_bh(&msk->join_list_lock);
453 }
454 
455 int mptcp_is_enabled(struct net *net);
456 unsigned int mptcp_get_add_addr_timeout(struct net *net);
457 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
458 				     struct mptcp_options_received *mp_opt);
459 bool mptcp_subflow_data_available(struct sock *sk);
460 void __init mptcp_subflow_init(void);
461 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
462 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
463 		       struct mptcp_subflow_context *subflow);
464 void mptcp_subflow_reset(struct sock *ssk);
465 
466 /* called with sk socket lock held */
467 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
468 			    const struct mptcp_addr_info *remote);
469 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
470 
471 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
472 					      struct mptcp_subflow_context *ctx)
473 {
474 	sk->sk_data_ready = ctx->tcp_data_ready;
475 	sk->sk_state_change = ctx->tcp_state_change;
476 	sk->sk_write_space = ctx->tcp_write_space;
477 
478 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
479 }
480 
481 void __init mptcp_proto_init(void);
482 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
483 int __init mptcp_proto_v6_init(void);
484 #endif
485 
486 struct sock *mptcp_sk_clone(const struct sock *sk,
487 			    const struct mptcp_options_received *mp_opt,
488 			    struct request_sock *req);
489 void mptcp_get_options(const struct sk_buff *skb,
490 		       struct mptcp_options_received *mp_opt);
491 
492 void mptcp_finish_connect(struct sock *sk);
493 static inline bool mptcp_is_fully_established(struct sock *sk)
494 {
495 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
496 	       READ_ONCE(mptcp_sk(sk)->fully_established);
497 }
498 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
499 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
500 bool mptcp_finish_join(struct sock *sk);
501 bool mptcp_schedule_work(struct sock *sk);
502 void __mptcp_wnd_updated(struct sock *sk, struct sock *ssk);
503 void __mptcp_data_acked(struct sock *sk);
504 void mptcp_subflow_eof(struct sock *sk);
505 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
506 void __mptcp_flush_join_list(struct mptcp_sock *msk);
507 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
508 {
509 	return READ_ONCE(msk->snd_data_fin_enable) &&
510 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
511 }
512 
513 void mptcp_destroy_common(struct mptcp_sock *msk);
514 
515 void __init mptcp_token_init(void);
516 static inline void mptcp_token_init_request(struct request_sock *req)
517 {
518 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
519 }
520 
521 int mptcp_token_new_request(struct request_sock *req);
522 void mptcp_token_destroy_request(struct request_sock *req);
523 int mptcp_token_new_connect(struct sock *sk);
524 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
525 			struct mptcp_sock *msk);
526 bool mptcp_token_exists(u32 token);
527 struct mptcp_sock *mptcp_token_get_sock(u32 token);
528 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
529 					 long *s_num);
530 void mptcp_token_destroy(struct mptcp_sock *msk);
531 
532 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
533 
534 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
535 
536 void __init mptcp_pm_init(void);
537 void mptcp_pm_data_init(struct mptcp_sock *msk);
538 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
539 void mptcp_pm_fully_established(struct mptcp_sock *msk);
540 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
541 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
542 void mptcp_pm_subflow_established(struct mptcp_sock *msk,
543 				  struct mptcp_subflow_context *subflow);
544 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
545 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
546 				const struct mptcp_addr_info *addr);
547 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
548 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
549 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
550 struct mptcp_pm_add_entry *
551 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
552 		       struct mptcp_addr_info *addr);
553 
554 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
555 			   const struct mptcp_addr_info *addr,
556 			   bool echo, bool port);
557 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
558 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id);
559 
560 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
561 {
562 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
563 }
564 
565 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
566 {
567 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
568 }
569 
570 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
571 {
572 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
573 }
574 
575 static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
576 {
577 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
578 }
579 
580 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
581 {
582 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
583 }
584 
585 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
586 {
587 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
588 
589 	if (family == AF_INET6)
590 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
591 	if (!echo)
592 		len += MPTCPOPT_THMAC_LEN;
593 	if (port)
594 		len += TCPOLEN_MPTCP_PORT_LEN;
595 
596 	return len;
597 }
598 
599 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
600 			      struct mptcp_addr_info *saddr, bool *echo, bool *port);
601 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
602 			     u8 *rm_id);
603 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
604 
605 void __init mptcp_pm_nl_init(void);
606 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
607 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
608 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
609 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
610 void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk);
611 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk);
612 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id);
613 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
614 
615 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
616 {
617 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
618 }
619 
620 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
621 
622 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
623 {
624 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
625 }
626 
627 static inline bool mptcp_check_fallback(const struct sock *sk)
628 {
629 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
630 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
631 
632 	return __mptcp_check_fallback(msk);
633 }
634 
635 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
636 {
637 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
638 		pr_debug("TCP fallback already done (msk=%p)", msk);
639 		return;
640 	}
641 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
642 }
643 
644 static inline void mptcp_do_fallback(struct sock *sk)
645 {
646 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
647 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
648 
649 	__mptcp_do_fallback(msk);
650 }
651 
652 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
653 
654 static inline bool subflow_simultaneous_connect(struct sock *sk)
655 {
656 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
657 	struct sock *parent = subflow->conn;
658 
659 	return sk->sk_state == TCP_ESTABLISHED &&
660 	       !mptcp_sk(parent)->pm.server_side &&
661 	       !subflow->conn_finished;
662 }
663 
664 #ifdef CONFIG_SYN_COOKIES
665 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
666 				       struct sk_buff *skb);
667 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
668 					struct sk_buff *skb);
669 void __init mptcp_join_cookie_init(void);
670 #else
671 static inline void
672 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
673 				  struct sk_buff *skb) {}
674 static inline bool
675 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
676 				   struct sk_buff *skb)
677 {
678 	return false;
679 }
680 
681 static inline void mptcp_join_cookie_init(void) {}
682 #endif
683 
684 #endif /* __MPTCP_PROTOCOL_H */
685