xref: /openbmc/linux/net/mptcp/protocol.h (revision 04295878beac396dae47ba93141cae0d9386e7ef)
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 
95 static inline bool before64(__u64 seq1, __u64 seq2)
96 {
97 	return (__s64)(seq1 - seq2) < 0;
98 }
99 
100 #define after64(seq2, seq1)	before64(seq1, seq2)
101 
102 struct mptcp_options_received {
103 	u64	sndr_key;
104 	u64	rcvr_key;
105 	u64	data_ack;
106 	u64	data_seq;
107 	u32	subflow_seq;
108 	u16	data_len;
109 	u16	mp_capable : 1,
110 		mp_join : 1,
111 		dss : 1,
112 		add_addr : 1,
113 		rm_addr : 1,
114 		family : 4,
115 		echo : 1,
116 		backup : 1;
117 	u32	token;
118 	u32	nonce;
119 	u64	thmac;
120 	u8	hmac[20];
121 	u8	join_id;
122 	u8	use_map:1,
123 		dsn64:1,
124 		data_fin:1,
125 		use_ack:1,
126 		ack64:1,
127 		mpc_map:1,
128 		__unused:2;
129 	u8	addr_id;
130 	u8	rm_id;
131 	union {
132 		struct in_addr	addr;
133 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
134 		struct in6_addr	addr6;
135 #endif
136 	};
137 	u64	ahmac;
138 	u16	port;
139 };
140 
141 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
142 {
143 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
144 		     ((nib & 0xF) << 8) | field);
145 }
146 
147 struct mptcp_addr_info {
148 	sa_family_t		family;
149 	__be16			port;
150 	u8			id;
151 	u8			flags;
152 	int			ifindex;
153 	union {
154 		struct in_addr addr;
155 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
156 		struct in6_addr addr6;
157 #endif
158 	};
159 };
160 
161 enum mptcp_pm_status {
162 	MPTCP_PM_ADD_ADDR_RECEIVED,
163 	MPTCP_PM_ADD_ADDR_SEND_ACK,
164 	MPTCP_PM_RM_ADDR_RECEIVED,
165 	MPTCP_PM_ESTABLISHED,
166 	MPTCP_PM_SUBFLOW_ESTABLISHED,
167 };
168 
169 enum mptcp_add_addr_status {
170 	MPTCP_ADD_ADDR_SIGNAL,
171 	MPTCP_ADD_ADDR_ECHO,
172 	MPTCP_ADD_ADDR_IPV6,
173 };
174 
175 struct mptcp_pm_data {
176 	struct mptcp_addr_info local;
177 	struct mptcp_addr_info remote;
178 	struct list_head anno_list;
179 
180 	spinlock_t	lock;		/*protects the whole PM data */
181 
182 	u8		add_addr_signal;
183 	bool		rm_addr_signal;
184 	bool		server_side;
185 	bool		work_pending;
186 	bool		accept_addr;
187 	bool		accept_subflow;
188 	u8		add_addr_signaled;
189 	u8		add_addr_accepted;
190 	u8		local_addr_used;
191 	u8		subflows;
192 	u8		add_addr_signal_max;
193 	u8		add_addr_accept_max;
194 	u8		local_addr_max;
195 	u8		subflows_max;
196 	u8		status;
197 	u8		rm_id;
198 };
199 
200 struct mptcp_data_frag {
201 	struct list_head list;
202 	u64 data_seq;
203 	u16 data_len;
204 	u16 offset;
205 	u16 overhead;
206 	u16 already_sent;
207 	struct page *page;
208 };
209 
210 /* MPTCP connection sock */
211 struct mptcp_sock {
212 	/* inet_connection_sock must be the first member */
213 	struct inet_connection_sock sk;
214 	u64		local_key;
215 	u64		remote_key;
216 	u64		write_seq;
217 	u64		snd_nxt;
218 	u64		ack_seq;
219 	u64		rcv_wnd_sent;
220 	u64		rcv_data_fin_seq;
221 	struct sock	*last_snd;
222 	int		snd_burst;
223 	int		old_wspace;
224 	atomic64_t	snd_una;
225 	atomic64_t	wnd_end;
226 	unsigned long	timer_ival;
227 	u32		token;
228 	int		rmem_pending;
229 	unsigned long	flags;
230 	bool		can_ack;
231 	bool		fully_established;
232 	bool		rcv_data_fin;
233 	bool		snd_data_fin_enable;
234 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
235 	spinlock_t	join_list_lock;
236 	struct sock	*ack_hint;
237 	struct work_struct work;
238 	struct sk_buff  *ooo_last_skb;
239 	struct rb_root  out_of_order_queue;
240 	struct list_head conn_list;
241 	struct list_head rtx_queue;
242 	struct mptcp_data_frag *first_pending;
243 	struct list_head join_list;
244 	struct skb_ext	*cached_ext;	/* for the next sendmsg */
245 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
246 	struct sock	*first;
247 	struct mptcp_pm_data	pm;
248 	struct {
249 		u32	space;	/* bytes copied in last measurement window */
250 		u32	copied; /* bytes copied in this measurement window */
251 		u64	time;	/* start time of measurement window */
252 		u64	rtt_us; /* last maximum rtt of subflows */
253 	} rcvq_space;
254 };
255 
256 #define mptcp_for_each_subflow(__msk, __subflow)			\
257 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
258 
259 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
260 {
261 	return (struct mptcp_sock *)sk;
262 }
263 
264 static inline int __mptcp_space(const struct sock *sk)
265 {
266 	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);
267 }
268 
269 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
270 {
271 	const struct mptcp_sock *msk = mptcp_sk(sk);
272 
273 	return READ_ONCE(msk->first_pending);
274 }
275 
276 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
277 {
278 	struct mptcp_sock *msk = mptcp_sk(sk);
279 	struct mptcp_data_frag *cur;
280 
281 	cur = msk->first_pending;
282 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
283 						     list_next_entry(cur, list);
284 }
285 
286 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
287 {
288 	struct mptcp_sock *msk = mptcp_sk(sk);
289 
290 	if (!msk->first_pending)
291 		return NULL;
292 
293 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
294 		return NULL;
295 
296 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
297 }
298 
299 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
300 {
301 	struct mptcp_sock *msk = mptcp_sk(sk);
302 
303 	if (!before64(msk->snd_nxt, atomic64_read(&msk->snd_una)))
304 		return NULL;
305 
306 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
307 }
308 
309 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
310 {
311 	struct mptcp_sock *msk = mptcp_sk(sk);
312 
313 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
314 }
315 
316 struct mptcp_subflow_request_sock {
317 	struct	tcp_request_sock sk;
318 	u16	mp_capable : 1,
319 		mp_join : 1,
320 		backup : 1;
321 	u8	local_id;
322 	u8	remote_id;
323 	u64	local_key;
324 	u64	idsn;
325 	u32	token;
326 	u32	ssn_offset;
327 	u64	thmac;
328 	u32	local_nonce;
329 	u32	remote_nonce;
330 	struct mptcp_sock	*msk;
331 	struct hlist_nulls_node token_node;
332 };
333 
334 static inline struct mptcp_subflow_request_sock *
335 mptcp_subflow_rsk(const struct request_sock *rsk)
336 {
337 	return (struct mptcp_subflow_request_sock *)rsk;
338 }
339 
340 enum mptcp_data_avail {
341 	MPTCP_SUBFLOW_NODATA,
342 	MPTCP_SUBFLOW_DATA_AVAIL,
343 	MPTCP_SUBFLOW_OOO_DATA
344 };
345 
346 /* MPTCP subflow context */
347 struct mptcp_subflow_context {
348 	struct	list_head node;/* conn_list of subflows */
349 	u64	local_key;
350 	u64	remote_key;
351 	u64	idsn;
352 	u64	map_seq;
353 	u32	snd_isn;
354 	u32	token;
355 	u32	rel_write_seq;
356 	u32	map_subflow_seq;
357 	u32	ssn_offset;
358 	u32	map_data_len;
359 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
360 		request_join : 1,   /* send MP_JOIN */
361 		request_bkup : 1,
362 		mp_capable : 1,	    /* remote is MPTCP capable */
363 		mp_join : 1,	    /* remote is JOINing */
364 		fully_established : 1,	    /* path validated */
365 		pm_notified : 1,    /* PM hook called for established status */
366 		conn_finished : 1,
367 		map_valid : 1,
368 		mpc_map : 1,
369 		backup : 1,
370 		rx_eof : 1,
371 		can_ack : 1,        /* only after processing the remote a key */
372 		disposable : 1;	    /* ctx can be free at ulp release time */
373 	enum mptcp_data_avail data_avail;
374 	u32	remote_nonce;
375 	u64	thmac;
376 	u32	local_nonce;
377 	u32	remote_token;
378 	u8	hmac[MPTCPOPT_HMAC_LEN];
379 	u8	local_id;
380 	u8	remote_id;
381 
382 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
383 	struct	sock *conn;	    /* parent mptcp_sock */
384 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
385 	void	(*tcp_data_ready)(struct sock *sk);
386 	void	(*tcp_state_change)(struct sock *sk);
387 	void	(*tcp_write_space)(struct sock *sk);
388 
389 	struct	rcu_head rcu;
390 };
391 
392 static inline struct mptcp_subflow_context *
393 mptcp_subflow_ctx(const struct sock *sk)
394 {
395 	struct inet_connection_sock *icsk = inet_csk(sk);
396 
397 	/* Use RCU on icsk_ulp_data only for sock diag code */
398 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
399 }
400 
401 static inline struct sock *
402 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
403 {
404 	return subflow->tcp_sock;
405 }
406 
407 static inline u64
408 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
409 {
410 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
411 		      subflow->ssn_offset -
412 		      subflow->map_subflow_seq;
413 }
414 
415 static inline u64
416 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
417 {
418 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
419 }
420 
421 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
422 					     struct mptcp_subflow_context *subflow)
423 {
424 	sock_hold(mptcp_subflow_tcp_sock(subflow));
425 	spin_lock_bh(&msk->join_list_lock);
426 	list_add_tail(&subflow->node, &msk->join_list);
427 	spin_unlock_bh(&msk->join_list_lock);
428 }
429 
430 int mptcp_is_enabled(struct net *net);
431 unsigned int mptcp_get_add_addr_timeout(struct net *net);
432 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
433 				     struct mptcp_options_received *mp_opt);
434 bool mptcp_subflow_data_available(struct sock *sk);
435 void __init mptcp_subflow_init(void);
436 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
437 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
438 		       struct mptcp_subflow_context *subflow);
439 void mptcp_subflow_reset(struct sock *ssk);
440 
441 /* called with sk socket lock held */
442 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
443 			    const struct mptcp_addr_info *remote);
444 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
445 
446 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
447 					      struct mptcp_subflow_context *ctx)
448 {
449 	sk->sk_data_ready = ctx->tcp_data_ready;
450 	sk->sk_state_change = ctx->tcp_state_change;
451 	sk->sk_write_space = ctx->tcp_write_space;
452 
453 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
454 }
455 
456 void __init mptcp_proto_init(void);
457 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
458 int __init mptcp_proto_v6_init(void);
459 #endif
460 
461 struct sock *mptcp_sk_clone(const struct sock *sk,
462 			    const struct mptcp_options_received *mp_opt,
463 			    struct request_sock *req);
464 void mptcp_get_options(const struct sk_buff *skb,
465 		       struct mptcp_options_received *mp_opt);
466 
467 void mptcp_finish_connect(struct sock *sk);
468 static inline bool mptcp_is_fully_established(struct sock *sk)
469 {
470 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
471 	       READ_ONCE(mptcp_sk(sk)->fully_established);
472 }
473 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
474 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
475 bool mptcp_finish_join(struct sock *sk);
476 bool mptcp_schedule_work(struct sock *sk);
477 void mptcp_data_acked(struct sock *sk);
478 void mptcp_subflow_eof(struct sock *sk);
479 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
480 void __mptcp_flush_join_list(struct mptcp_sock *msk);
481 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
482 {
483 	return READ_ONCE(msk->snd_data_fin_enable) &&
484 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
485 }
486 
487 void mptcp_destroy_common(struct mptcp_sock *msk);
488 
489 void __init mptcp_token_init(void);
490 static inline void mptcp_token_init_request(struct request_sock *req)
491 {
492 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
493 }
494 
495 int mptcp_token_new_request(struct request_sock *req);
496 void mptcp_token_destroy_request(struct request_sock *req);
497 int mptcp_token_new_connect(struct sock *sk);
498 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
499 			struct mptcp_sock *msk);
500 bool mptcp_token_exists(u32 token);
501 struct mptcp_sock *mptcp_token_get_sock(u32 token);
502 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
503 					 long *s_num);
504 void mptcp_token_destroy(struct mptcp_sock *msk);
505 
506 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
507 
508 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
509 
510 void __init mptcp_pm_init(void);
511 void mptcp_pm_data_init(struct mptcp_sock *msk);
512 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
513 void mptcp_pm_fully_established(struct mptcp_sock *msk);
514 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
515 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
516 void mptcp_pm_subflow_established(struct mptcp_sock *msk,
517 				  struct mptcp_subflow_context *subflow);
518 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
519 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
520 				const struct mptcp_addr_info *addr);
521 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
522 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
523 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
524 struct mptcp_pm_add_entry *
525 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
526 		       struct mptcp_addr_info *addr);
527 
528 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
529 			   const struct mptcp_addr_info *addr,
530 			   bool echo);
531 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
532 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id);
533 
534 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
535 {
536 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
537 }
538 
539 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
540 {
541 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
542 }
543 
544 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
545 {
546 	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
547 }
548 
549 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
550 {
551 	return READ_ONCE(msk->pm.rm_addr_signal);
552 }
553 
554 static inline unsigned int mptcp_add_addr_len(int family, bool echo)
555 {
556 	if (family == AF_INET)
557 		return echo ? TCPOLEN_MPTCP_ADD_ADDR_BASE
558 			    : TCPOLEN_MPTCP_ADD_ADDR;
559 	return echo ? TCPOLEN_MPTCP_ADD_ADDR6_BASE : TCPOLEN_MPTCP_ADD_ADDR6;
560 }
561 
562 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
563 			      struct mptcp_addr_info *saddr, bool *echo);
564 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
565 			     u8 *rm_id);
566 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
567 
568 void __init mptcp_pm_nl_init(void);
569 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
570 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
571 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
572 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
573 void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk);
574 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk);
575 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id);
576 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
577 
578 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
579 {
580 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
581 }
582 
583 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
584 
585 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
586 {
587 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
588 }
589 
590 static inline bool mptcp_check_fallback(const struct sock *sk)
591 {
592 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
593 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
594 
595 	return __mptcp_check_fallback(msk);
596 }
597 
598 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
599 {
600 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
601 		pr_debug("TCP fallback already done (msk=%p)", msk);
602 		return;
603 	}
604 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
605 }
606 
607 static inline void mptcp_do_fallback(struct sock *sk)
608 {
609 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
610 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
611 
612 	__mptcp_do_fallback(msk);
613 }
614 
615 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
616 
617 static inline bool subflow_simultaneous_connect(struct sock *sk)
618 {
619 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
620 	struct sock *parent = subflow->conn;
621 
622 	return sk->sk_state == TCP_ESTABLISHED &&
623 	       !mptcp_sk(parent)->pm.server_side &&
624 	       !subflow->conn_finished;
625 }
626 
627 #ifdef CONFIG_SYN_COOKIES
628 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
629 				       struct sk_buff *skb);
630 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
631 					struct sk_buff *skb);
632 void __init mptcp_join_cookie_init(void);
633 #else
634 static inline void
635 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
636 				  struct sk_buff *skb) {}
637 static inline bool
638 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
639 				   struct sk_buff *skb)
640 {
641 	return false;
642 }
643 
644 static inline void mptcp_join_cookie_init(void) {}
645 #endif
646 
647 #endif /* __MPTCP_PROTOCOL_H */
648