xref: /linux/net/mptcp/protocol.h (revision 7f356166aebb0d956d367dfe55e19d7783277d09)
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	18
53 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
54 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
55 #define TCPOLEN_MPTCP_ADD_ADDR6		28
56 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
57 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
58 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
59 #define TCPOLEN_MPTCP_PORT_LEN		2
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_SUBFLOW_ESTABLISHED,
169 };
170 
171 enum mptcp_add_addr_status {
172 	MPTCP_ADD_ADDR_SIGNAL,
173 	MPTCP_ADD_ADDR_ECHO,
174 	MPTCP_ADD_ADDR_IPV6,
175 };
176 
177 struct mptcp_pm_data {
178 	struct mptcp_addr_info local;
179 	struct mptcp_addr_info remote;
180 	struct list_head anno_list;
181 
182 	spinlock_t	lock;		/*protects the whole PM data */
183 
184 	u8		add_addr_signal;
185 	bool		rm_addr_signal;
186 	bool		server_side;
187 	bool		work_pending;
188 	bool		accept_addr;
189 	bool		accept_subflow;
190 	u8		add_addr_signaled;
191 	u8		add_addr_accepted;
192 	u8		local_addr_used;
193 	u8		subflows;
194 	u8		add_addr_signal_max;
195 	u8		add_addr_accept_max;
196 	u8		local_addr_max;
197 	u8		subflows_max;
198 	u8		status;
199 	u8		rm_id;
200 };
201 
202 struct mptcp_data_frag {
203 	struct list_head list;
204 	u64 data_seq;
205 	u16 data_len;
206 	u16 offset;
207 	u16 overhead;
208 	u16 already_sent;
209 	struct page *page;
210 };
211 
212 /* MPTCP connection sock */
213 struct mptcp_sock {
214 	/* inet_connection_sock must be the first member */
215 	struct inet_connection_sock sk;
216 	u64		local_key;
217 	u64		remote_key;
218 	u64		write_seq;
219 	u64		snd_nxt;
220 	u64		ack_seq;
221 	u64		rcv_wnd_sent;
222 	u64		rcv_data_fin_seq;
223 	int		wmem_reserved;
224 	struct sock	*last_snd;
225 	int		snd_burst;
226 	int		old_wspace;
227 	u64		snd_una;
228 	u64		wnd_end;
229 	unsigned long	timer_ival;
230 	u32		token;
231 	int		rmem_pending;
232 	int		rmem_released;
233 	unsigned long	flags;
234 	bool		can_ack;
235 	bool		fully_established;
236 	bool		rcv_data_fin;
237 	bool		snd_data_fin_enable;
238 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
239 	spinlock_t	join_list_lock;
240 	struct sock	*ack_hint;
241 	struct work_struct work;
242 	struct sk_buff  *ooo_last_skb;
243 	struct rb_root  out_of_order_queue;
244 	struct sk_buff_head receive_queue;
245 	struct sk_buff_head skb_tx_cache;	/* this is wmem accounted */
246 	int		tx_pending_data;
247 	int		size_goal_cache;
248 	struct list_head conn_list;
249 	struct list_head rtx_queue;
250 	struct mptcp_data_frag *first_pending;
251 	struct list_head join_list;
252 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
253 	struct sock	*first;
254 	struct mptcp_pm_data	pm;
255 	struct {
256 		u32	space;	/* bytes copied in last measurement window */
257 		u32	copied; /* bytes copied in this measurement window */
258 		u64	time;	/* start time of measurement window */
259 		u64	rtt_us; /* last maximum rtt of subflows */
260 	} rcvq_space;
261 };
262 
263 #define mptcp_lock_sock(___sk, cb) do {					\
264 	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
265 	might_sleep();							\
266 	spin_lock_bh(&__sk->sk_lock.slock);				\
267 	if (__sk->sk_lock.owned)					\
268 		__lock_sock(__sk);					\
269 	cb;								\
270 	__sk->sk_lock.owned = 1;					\
271 	spin_unlock(&__sk->sk_lock.slock);				\
272 	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
273 	local_bh_enable();						\
274 } while (0)
275 
276 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
277 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
278 
279 #define mptcp_for_each_subflow(__msk, __subflow)			\
280 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
281 
282 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
283 {
284 	return (struct mptcp_sock *)sk;
285 }
286 
287 static inline int __mptcp_space(const struct sock *sk)
288 {
289 	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);
290 }
291 
292 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
293 {
294 	const struct mptcp_sock *msk = mptcp_sk(sk);
295 
296 	return READ_ONCE(msk->first_pending);
297 }
298 
299 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
300 {
301 	struct mptcp_sock *msk = mptcp_sk(sk);
302 	struct mptcp_data_frag *cur;
303 
304 	cur = msk->first_pending;
305 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
306 						     list_next_entry(cur, list);
307 }
308 
309 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
310 {
311 	struct mptcp_sock *msk = mptcp_sk(sk);
312 
313 	if (!msk->first_pending)
314 		return NULL;
315 
316 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
317 		return NULL;
318 
319 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
320 }
321 
322 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
323 {
324 	struct mptcp_sock *msk = mptcp_sk(sk);
325 
326 	if (!before64(msk->snd_nxt, READ_ONCE(msk->snd_una)))
327 		return NULL;
328 
329 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
330 }
331 
332 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
333 {
334 	struct mptcp_sock *msk = mptcp_sk(sk);
335 
336 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
337 }
338 
339 struct mptcp_subflow_request_sock {
340 	struct	tcp_request_sock sk;
341 	u16	mp_capable : 1,
342 		mp_join : 1,
343 		backup : 1;
344 	u8	local_id;
345 	u8	remote_id;
346 	u64	local_key;
347 	u64	idsn;
348 	u32	token;
349 	u32	ssn_offset;
350 	u64	thmac;
351 	u32	local_nonce;
352 	u32	remote_nonce;
353 	struct mptcp_sock	*msk;
354 	struct hlist_nulls_node token_node;
355 };
356 
357 static inline struct mptcp_subflow_request_sock *
358 mptcp_subflow_rsk(const struct request_sock *rsk)
359 {
360 	return (struct mptcp_subflow_request_sock *)rsk;
361 }
362 
363 enum mptcp_data_avail {
364 	MPTCP_SUBFLOW_NODATA,
365 	MPTCP_SUBFLOW_DATA_AVAIL,
366 	MPTCP_SUBFLOW_OOO_DATA
367 };
368 
369 /* MPTCP subflow context */
370 struct mptcp_subflow_context {
371 	struct	list_head node;/* conn_list of subflows */
372 	u64	local_key;
373 	u64	remote_key;
374 	u64	idsn;
375 	u64	map_seq;
376 	u32	snd_isn;
377 	u32	token;
378 	u32	rel_write_seq;
379 	u32	map_subflow_seq;
380 	u32	ssn_offset;
381 	u32	map_data_len;
382 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
383 		request_join : 1,   /* send MP_JOIN */
384 		request_bkup : 1,
385 		mp_capable : 1,	    /* remote is MPTCP capable */
386 		mp_join : 1,	    /* remote is JOINing */
387 		fully_established : 1,	    /* path validated */
388 		pm_notified : 1,    /* PM hook called for established status */
389 		conn_finished : 1,
390 		map_valid : 1,
391 		mpc_map : 1,
392 		backup : 1,
393 		rx_eof : 1,
394 		can_ack : 1,        /* only after processing the remote a key */
395 		disposable : 1;	    /* ctx can be free at ulp release time */
396 	enum mptcp_data_avail data_avail;
397 	u32	remote_nonce;
398 	u64	thmac;
399 	u32	local_nonce;
400 	u32	remote_token;
401 	u8	hmac[MPTCPOPT_HMAC_LEN];
402 	u8	local_id;
403 	u8	remote_id;
404 
405 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
406 	struct	sock *conn;	    /* parent mptcp_sock */
407 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
408 	void	(*tcp_data_ready)(struct sock *sk);
409 	void	(*tcp_state_change)(struct sock *sk);
410 	void	(*tcp_write_space)(struct sock *sk);
411 
412 	struct	rcu_head rcu;
413 };
414 
415 static inline struct mptcp_subflow_context *
416 mptcp_subflow_ctx(const struct sock *sk)
417 {
418 	struct inet_connection_sock *icsk = inet_csk(sk);
419 
420 	/* Use RCU on icsk_ulp_data only for sock diag code */
421 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
422 }
423 
424 static inline struct sock *
425 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
426 {
427 	return subflow->tcp_sock;
428 }
429 
430 static inline u64
431 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
432 {
433 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
434 		      subflow->ssn_offset -
435 		      subflow->map_subflow_seq;
436 }
437 
438 static inline u64
439 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
440 {
441 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
442 }
443 
444 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
445 					     struct mptcp_subflow_context *subflow)
446 {
447 	sock_hold(mptcp_subflow_tcp_sock(subflow));
448 	spin_lock_bh(&msk->join_list_lock);
449 	list_add_tail(&subflow->node, &msk->join_list);
450 	spin_unlock_bh(&msk->join_list_lock);
451 }
452 
453 int mptcp_is_enabled(struct net *net);
454 unsigned int mptcp_get_add_addr_timeout(struct net *net);
455 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
456 				     struct mptcp_options_received *mp_opt);
457 bool mptcp_subflow_data_available(struct sock *sk);
458 void __init mptcp_subflow_init(void);
459 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
460 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
461 		       struct mptcp_subflow_context *subflow);
462 void mptcp_subflow_reset(struct sock *ssk);
463 
464 /* called with sk socket lock held */
465 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
466 			    const struct mptcp_addr_info *remote);
467 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
468 
469 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
470 					      struct mptcp_subflow_context *ctx)
471 {
472 	sk->sk_data_ready = ctx->tcp_data_ready;
473 	sk->sk_state_change = ctx->tcp_state_change;
474 	sk->sk_write_space = ctx->tcp_write_space;
475 
476 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
477 }
478 
479 void __init mptcp_proto_init(void);
480 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
481 int __init mptcp_proto_v6_init(void);
482 #endif
483 
484 struct sock *mptcp_sk_clone(const struct sock *sk,
485 			    const struct mptcp_options_received *mp_opt,
486 			    struct request_sock *req);
487 void mptcp_get_options(const struct sk_buff *skb,
488 		       struct mptcp_options_received *mp_opt);
489 
490 void mptcp_finish_connect(struct sock *sk);
491 static inline bool mptcp_is_fully_established(struct sock *sk)
492 {
493 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
494 	       READ_ONCE(mptcp_sk(sk)->fully_established);
495 }
496 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
497 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
498 bool mptcp_finish_join(struct sock *sk);
499 bool mptcp_schedule_work(struct sock *sk);
500 void __mptcp_wnd_updated(struct sock *sk, struct sock *ssk);
501 void __mptcp_data_acked(struct sock *sk);
502 void mptcp_subflow_eof(struct sock *sk);
503 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
504 void __mptcp_flush_join_list(struct mptcp_sock *msk);
505 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
506 {
507 	return READ_ONCE(msk->snd_data_fin_enable) &&
508 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
509 }
510 
511 void mptcp_destroy_common(struct mptcp_sock *msk);
512 
513 void __init mptcp_token_init(void);
514 static inline void mptcp_token_init_request(struct request_sock *req)
515 {
516 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
517 }
518 
519 int mptcp_token_new_request(struct request_sock *req);
520 void mptcp_token_destroy_request(struct request_sock *req);
521 int mptcp_token_new_connect(struct sock *sk);
522 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
523 			struct mptcp_sock *msk);
524 bool mptcp_token_exists(u32 token);
525 struct mptcp_sock *mptcp_token_get_sock(u32 token);
526 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
527 					 long *s_num);
528 void mptcp_token_destroy(struct mptcp_sock *msk);
529 
530 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
531 
532 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
533 
534 void __init mptcp_pm_init(void);
535 void mptcp_pm_data_init(struct mptcp_sock *msk);
536 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
537 void mptcp_pm_fully_established(struct mptcp_sock *msk);
538 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
539 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
540 void mptcp_pm_subflow_established(struct mptcp_sock *msk,
541 				  struct mptcp_subflow_context *subflow);
542 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
543 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
544 				const struct mptcp_addr_info *addr);
545 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
546 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
547 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
548 struct mptcp_pm_add_entry *
549 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
550 		       struct mptcp_addr_info *addr);
551 
552 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
553 			   const struct mptcp_addr_info *addr,
554 			   bool echo);
555 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
556 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id);
557 
558 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
559 {
560 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
561 }
562 
563 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
564 {
565 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
566 }
567 
568 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
569 {
570 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
571 }
572 
573 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
574 {
575 	return READ_ONCE(msk->pm.rm_addr_signal);
576 }
577 
578 static inline unsigned int mptcp_add_addr_len(int family, bool echo)
579 {
580 	if (family == AF_INET)
581 		return echo ? TCPOLEN_MPTCP_ADD_ADDR_BASE
582 			    : TCPOLEN_MPTCP_ADD_ADDR;
583 	return echo ? TCPOLEN_MPTCP_ADD_ADDR6_BASE : TCPOLEN_MPTCP_ADD_ADDR6;
584 }
585 
586 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
587 			      struct mptcp_addr_info *saddr, bool *echo);
588 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
589 			     u8 *rm_id);
590 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
591 
592 void __init mptcp_pm_nl_init(void);
593 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
594 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
595 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
596 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
597 void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk);
598 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk);
599 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id);
600 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
601 
602 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
603 {
604 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
605 }
606 
607 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
608 
609 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
610 {
611 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
612 }
613 
614 static inline bool mptcp_check_fallback(const struct sock *sk)
615 {
616 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
617 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
618 
619 	return __mptcp_check_fallback(msk);
620 }
621 
622 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
623 {
624 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
625 		pr_debug("TCP fallback already done (msk=%p)", msk);
626 		return;
627 	}
628 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
629 }
630 
631 static inline void mptcp_do_fallback(struct sock *sk)
632 {
633 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
634 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
635 
636 	__mptcp_do_fallback(msk);
637 }
638 
639 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
640 
641 static inline bool subflow_simultaneous_connect(struct sock *sk)
642 {
643 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
644 	struct sock *parent = subflow->conn;
645 
646 	return sk->sk_state == TCP_ESTABLISHED &&
647 	       !mptcp_sk(parent)->pm.server_side &&
648 	       !subflow->conn_finished;
649 }
650 
651 #ifdef CONFIG_SYN_COOKIES
652 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
653 				       struct sk_buff *skb);
654 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
655 					struct sk_buff *skb);
656 void __init mptcp_join_cookie_init(void);
657 #else
658 static inline void
659 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
660 				  struct sk_buff *skb) {}
661 static inline bool
662 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
663 				   struct sk_buff *skb)
664 {
665 	return false;
666 }
667 
668 static inline void mptcp_join_cookie_init(void) {}
669 #endif
670 
671 #endif /* __MPTCP_PROTOCOL_H */
672