xref: /openbmc/linux/net/mptcp/protocol.h (revision 6da14d74e2bd07bca2cba10878dda5dc0485d59c)
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 
15 #define MPTCP_SUPPORTED_VERSION	1
16 
17 /* MPTCP option bits */
18 #define OPTION_MPTCP_MPC_SYN	BIT(0)
19 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
20 #define OPTION_MPTCP_MPC_ACK	BIT(2)
21 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
22 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
23 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
24 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
25 #define OPTION_MPTCP_RM_ADDR	BIT(7)
26 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
27 #define OPTION_MPTCP_PRIO	BIT(9)
28 #define OPTION_MPTCP_RST	BIT(10)
29 
30 /* MPTCP option subtypes */
31 #define MPTCPOPT_MP_CAPABLE	0
32 #define MPTCPOPT_MP_JOIN	1
33 #define MPTCPOPT_DSS		2
34 #define MPTCPOPT_ADD_ADDR	3
35 #define MPTCPOPT_RM_ADDR	4
36 #define MPTCPOPT_MP_PRIO	5
37 #define MPTCPOPT_MP_FAIL	6
38 #define MPTCPOPT_MP_FASTCLOSE	7
39 #define MPTCPOPT_RST		8
40 
41 /* MPTCP suboption lengths */
42 #define TCPOLEN_MPTCP_MPC_SYN		4
43 #define TCPOLEN_MPTCP_MPC_SYNACK	12
44 #define TCPOLEN_MPTCP_MPC_ACK		20
45 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
46 #define TCPOLEN_MPTCP_MPJ_SYN		12
47 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
48 #define TCPOLEN_MPTCP_MPJ_ACK		24
49 #define TCPOLEN_MPTCP_DSS_BASE		4
50 #define TCPOLEN_MPTCP_DSS_ACK32		4
51 #define TCPOLEN_MPTCP_DSS_ACK64		8
52 #define TCPOLEN_MPTCP_DSS_MAP32		10
53 #define TCPOLEN_MPTCP_DSS_MAP64		14
54 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
55 #define TCPOLEN_MPTCP_ADD_ADDR		16
56 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
57 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
58 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
59 #define TCPOLEN_MPTCP_ADD_ADDR6		28
60 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
61 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
62 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
63 #define TCPOLEN_MPTCP_PORT_LEN		2
64 #define TCPOLEN_MPTCP_PORT_ALIGN	2
65 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
66 #define TCPOLEN_MPTCP_PRIO		3
67 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
68 #define TCPOLEN_MPTCP_FASTCLOSE		12
69 #define TCPOLEN_MPTCP_RST		4
70 
71 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
72 
73 /* MPTCP MP_JOIN flags */
74 #define MPTCPOPT_BACKUP		BIT(0)
75 #define MPTCPOPT_HMAC_LEN	20
76 #define MPTCPOPT_THMAC_LEN	8
77 
78 /* MPTCP MP_CAPABLE flags */
79 #define MPTCP_VERSION_MASK	(0x0F)
80 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
81 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
82 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
83 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
84 #define MPTCP_CAP_FLAG_MASK	(0x1F)
85 
86 /* MPTCP DSS flags */
87 #define MPTCP_DSS_DATA_FIN	BIT(4)
88 #define MPTCP_DSS_DSN64		BIT(3)
89 #define MPTCP_DSS_HAS_MAP	BIT(2)
90 #define MPTCP_DSS_ACK64		BIT(1)
91 #define MPTCP_DSS_HAS_ACK	BIT(0)
92 #define MPTCP_DSS_FLAG_MASK	(0x1F)
93 
94 /* MPTCP ADD_ADDR flags */
95 #define MPTCP_ADDR_ECHO		BIT(0)
96 
97 /* MPTCP MP_PRIO flags */
98 #define MPTCP_PRIO_BKUP		BIT(0)
99 
100 /* MPTCP TCPRST flags */
101 #define MPTCP_RST_TRANSIENT	BIT(0)
102 
103 /* MPTCP socket flags */
104 #define MPTCP_DATA_READY	0
105 #define MPTCP_NOSPACE		1
106 #define MPTCP_WORK_RTX		2
107 #define MPTCP_WORK_EOF		3
108 #define MPTCP_FALLBACK_DONE	4
109 #define MPTCP_WORK_CLOSE_SUBFLOW 5
110 #define MPTCP_PUSH_PENDING	6
111 #define MPTCP_CLEAN_UNA		7
112 #define MPTCP_ERROR_REPORT	8
113 #define MPTCP_RETRANSMIT	9
114 #define MPTCP_WORK_SYNC_SETSOCKOPT 10
115 #define MPTCP_CONNECTED		11
116 
117 static inline bool before64(__u64 seq1, __u64 seq2)
118 {
119 	return (__s64)(seq1 - seq2) < 0;
120 }
121 
122 #define after64(seq2, seq1)	before64(seq1, seq2)
123 
124 struct mptcp_options_received {
125 	u64	sndr_key;
126 	u64	rcvr_key;
127 	u64	data_ack;
128 	u64	data_seq;
129 	u32	subflow_seq;
130 	u16	data_len;
131 	__sum16	csum;
132 	u16	mp_capable : 1,
133 		mp_join : 1,
134 		fastclose : 1,
135 		reset : 1,
136 		dss : 1,
137 		add_addr : 1,
138 		rm_addr : 1,
139 		mp_prio : 1,
140 		echo : 1,
141 		csum_reqd : 1,
142 		backup : 1,
143 		deny_join_id0 : 1;
144 	u32	token;
145 	u32	nonce;
146 	u64	thmac;
147 	u8	hmac[MPTCPOPT_HMAC_LEN];
148 	u8	join_id;
149 	u8	use_map:1,
150 		dsn64:1,
151 		data_fin:1,
152 		use_ack:1,
153 		ack64:1,
154 		mpc_map:1,
155 		__unused:2;
156 	struct mptcp_addr_info addr;
157 	struct mptcp_rm_list rm_list;
158 	u64	ahmac;
159 	u8	reset_reason:4;
160 	u8	reset_transient:1;
161 };
162 
163 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
164 {
165 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
166 		     ((nib & 0xF) << 8) | field);
167 }
168 
169 enum mptcp_pm_status {
170 	MPTCP_PM_ADD_ADDR_RECEIVED,
171 	MPTCP_PM_ADD_ADDR_SEND_ACK,
172 	MPTCP_PM_RM_ADDR_RECEIVED,
173 	MPTCP_PM_ESTABLISHED,
174 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
175 	MPTCP_PM_SUBFLOW_ESTABLISHED,
176 };
177 
178 enum mptcp_addr_signal_status {
179 	MPTCP_ADD_ADDR_SIGNAL,
180 	MPTCP_ADD_ADDR_ECHO,
181 	MPTCP_ADD_ADDR_IPV6,
182 	MPTCP_ADD_ADDR_PORT,
183 	MPTCP_RM_ADDR_SIGNAL,
184 };
185 
186 struct mptcp_pm_data {
187 	struct mptcp_addr_info local;
188 	struct mptcp_addr_info remote;
189 	struct list_head anno_list;
190 
191 	spinlock_t	lock;		/*protects the whole PM data */
192 
193 	u8		addr_signal;
194 	bool		server_side;
195 	bool		work_pending;
196 	bool		accept_addr;
197 	bool		accept_subflow;
198 	bool		remote_deny_join_id0;
199 	u8		add_addr_signaled;
200 	u8		add_addr_accepted;
201 	u8		local_addr_used;
202 	u8		subflows;
203 	u8		status;
204 	struct mptcp_rm_list rm_list_tx;
205 	struct mptcp_rm_list rm_list_rx;
206 };
207 
208 struct mptcp_data_frag {
209 	struct list_head list;
210 	u64 data_seq;
211 	u16 data_len;
212 	u16 offset;
213 	u16 overhead;
214 	u16 already_sent;
215 	struct page *page;
216 };
217 
218 /* MPTCP connection sock */
219 struct mptcp_sock {
220 	/* inet_connection_sock must be the first member */
221 	struct inet_connection_sock sk;
222 	u64		local_key;
223 	u64		remote_key;
224 	u64		write_seq;
225 	u64		snd_nxt;
226 	u64		ack_seq;
227 	u64		rcv_wnd_sent;
228 	u64		rcv_data_fin_seq;
229 	int		wmem_reserved;
230 	struct sock	*last_snd;
231 	int		snd_burst;
232 	int		old_wspace;
233 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
234 						 * recovery related fields are under data_lock
235 						 * protection
236 						 */
237 	u64		snd_una;
238 	u64		wnd_end;
239 	unsigned long	timer_ival;
240 	u32		token;
241 	int		rmem_released;
242 	unsigned long	flags;
243 	bool		recovery;		/* closing subflow write queue reinjected */
244 	bool		can_ack;
245 	bool		fully_established;
246 	bool		rcv_data_fin;
247 	bool		snd_data_fin_enable;
248 	bool		rcv_fastclose;
249 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
250 	bool		csum_enabled;
251 	spinlock_t	join_list_lock;
252 	struct work_struct work;
253 	struct sk_buff  *ooo_last_skb;
254 	struct rb_root  out_of_order_queue;
255 	struct sk_buff_head receive_queue;
256 	int		tx_pending_data;
257 	struct list_head conn_list;
258 	struct list_head rtx_queue;
259 	struct mptcp_data_frag *first_pending;
260 	struct list_head join_list;
261 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
262 	struct sock	*first;
263 	struct mptcp_pm_data	pm;
264 	struct {
265 		u32	space;	/* bytes copied in last measurement window */
266 		u32	copied; /* bytes copied in this measurement window */
267 		u64	time;	/* start time of measurement window */
268 		u64	rtt_us; /* last maximum rtt of subflows */
269 	} rcvq_space;
270 
271 	u32 setsockopt_seq;
272 	char		ca_name[TCP_CA_NAME_MAX];
273 };
274 
275 #define mptcp_lock_sock(___sk, cb) do {					\
276 	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
277 	might_sleep();							\
278 	spin_lock_bh(&__sk->sk_lock.slock);				\
279 	if (__sk->sk_lock.owned)					\
280 		__lock_sock(__sk);					\
281 	cb;								\
282 	__sk->sk_lock.owned = 1;					\
283 	spin_unlock(&__sk->sk_lock.slock);				\
284 	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
285 	local_bh_enable();						\
286 } while (0)
287 
288 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
289 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
290 
291 #define mptcp_for_each_subflow(__msk, __subflow)			\
292 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
293 
294 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
295 {
296 	sock_owned_by_me((const struct sock *)msk);
297 }
298 
299 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
300 {
301 	return (struct mptcp_sock *)sk;
302 }
303 
304 /* the msk socket don't use the backlog, also account for the bulk
305  * free memory
306  */
307 static inline int __mptcp_rmem(const struct sock *sk)
308 {
309 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
310 }
311 
312 static inline int __mptcp_space(const struct sock *sk)
313 {
314 	return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
315 }
316 
317 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
318 {
319 	const struct mptcp_sock *msk = mptcp_sk(sk);
320 
321 	return READ_ONCE(msk->first_pending);
322 }
323 
324 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
325 {
326 	struct mptcp_sock *msk = mptcp_sk(sk);
327 	struct mptcp_data_frag *cur;
328 
329 	cur = msk->first_pending;
330 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
331 						     list_next_entry(cur, list);
332 }
333 
334 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
335 {
336 	struct mptcp_sock *msk = mptcp_sk(sk);
337 
338 	if (!msk->first_pending)
339 		return NULL;
340 
341 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
342 		return NULL;
343 
344 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
345 }
346 
347 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
348 {
349 	struct mptcp_sock *msk = mptcp_sk(sk);
350 
351 	if (msk->snd_una == READ_ONCE(msk->snd_nxt))
352 		return NULL;
353 
354 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
355 }
356 
357 struct csum_pseudo_header {
358 	__be64 data_seq;
359 	__be32 subflow_seq;
360 	__be16 data_len;
361 	__sum16 csum;
362 };
363 
364 struct mptcp_subflow_request_sock {
365 	struct	tcp_request_sock sk;
366 	u16	mp_capable : 1,
367 		mp_join : 1,
368 		backup : 1,
369 		csum_reqd : 1,
370 		allow_join_id0 : 1;
371 	u8	local_id;
372 	u8	remote_id;
373 	u64	local_key;
374 	u64	idsn;
375 	u32	token;
376 	u32	ssn_offset;
377 	u64	thmac;
378 	u32	local_nonce;
379 	u32	remote_nonce;
380 	struct mptcp_sock	*msk;
381 	struct hlist_nulls_node token_node;
382 };
383 
384 static inline struct mptcp_subflow_request_sock *
385 mptcp_subflow_rsk(const struct request_sock *rsk)
386 {
387 	return (struct mptcp_subflow_request_sock *)rsk;
388 }
389 
390 enum mptcp_data_avail {
391 	MPTCP_SUBFLOW_NODATA,
392 	MPTCP_SUBFLOW_DATA_AVAIL,
393 };
394 
395 struct mptcp_delegated_action {
396 	struct napi_struct napi;
397 	struct list_head head;
398 };
399 
400 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
401 
402 #define MPTCP_DELEGATE_SEND		0
403 
404 /* MPTCP subflow context */
405 struct mptcp_subflow_context {
406 	struct	list_head node;/* conn_list of subflows */
407 	u64	local_key;
408 	u64	remote_key;
409 	u64	idsn;
410 	u64	map_seq;
411 	u32	snd_isn;
412 	u32	token;
413 	u32	rel_write_seq;
414 	u32	map_subflow_seq;
415 	u32	ssn_offset;
416 	u32	map_data_len;
417 	__wsum	map_data_csum;
418 	u32	map_csum_len;
419 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
420 		request_join : 1,   /* send MP_JOIN */
421 		request_bkup : 1,
422 		mp_capable : 1,	    /* remote is MPTCP capable */
423 		mp_join : 1,	    /* remote is JOINing */
424 		fully_established : 1,	    /* path validated */
425 		pm_notified : 1,    /* PM hook called for established status */
426 		conn_finished : 1,
427 		map_valid : 1,
428 		map_csum_reqd : 1,
429 		map_data_fin : 1,
430 		mpc_map : 1,
431 		backup : 1,
432 		send_mp_prio : 1,
433 		rx_eof : 1,
434 		can_ack : 1,        /* only after processing the remote a key */
435 		disposable : 1;	    /* ctx can be free at ulp release time */
436 	enum mptcp_data_avail data_avail;
437 	u32	remote_nonce;
438 	u64	thmac;
439 	u32	local_nonce;
440 	u32	remote_token;
441 	u8	hmac[MPTCPOPT_HMAC_LEN];
442 	u8	local_id;
443 	u8	remote_id;
444 	u8	reset_seen:1;
445 	u8	reset_transient:1;
446 	u8	reset_reason:4;
447 	u8	stale_count;
448 
449 	long	delegated_status;
450 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
451 
452 	u32	setsockopt_seq;
453 	u32	stale_rcv_tstamp;
454 
455 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
456 	struct	sock *conn;	    /* parent mptcp_sock */
457 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
458 	void	(*tcp_data_ready)(struct sock *sk);
459 	void	(*tcp_state_change)(struct sock *sk);
460 	void	(*tcp_write_space)(struct sock *sk);
461 	void	(*tcp_error_report)(struct sock *sk);
462 
463 	struct	rcu_head rcu;
464 };
465 
466 static inline struct mptcp_subflow_context *
467 mptcp_subflow_ctx(const struct sock *sk)
468 {
469 	struct inet_connection_sock *icsk = inet_csk(sk);
470 
471 	/* Use RCU on icsk_ulp_data only for sock diag code */
472 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
473 }
474 
475 static inline struct sock *
476 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
477 {
478 	return subflow->tcp_sock;
479 }
480 
481 static inline u64
482 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
483 {
484 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
485 		      subflow->ssn_offset -
486 		      subflow->map_subflow_seq;
487 }
488 
489 static inline u64
490 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
491 {
492 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
493 }
494 
495 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
496 					     struct mptcp_subflow_context *subflow)
497 {
498 	sock_hold(mptcp_subflow_tcp_sock(subflow));
499 	spin_lock_bh(&msk->join_list_lock);
500 	list_add_tail(&subflow->node, &msk->join_list);
501 	spin_unlock_bh(&msk->join_list_lock);
502 }
503 
504 void mptcp_subflow_process_delegated(struct sock *ssk);
505 
506 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow)
507 {
508 	struct mptcp_delegated_action *delegated;
509 	bool schedule;
510 
511 	/* The implied barrier pairs with mptcp_subflow_delegated_done(), and
512 	 * ensures the below list check sees list updates done prior to status
513 	 * bit changes
514 	 */
515 	if (!test_and_set_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
516 		/* still on delegated list from previous scheduling */
517 		if (!list_empty(&subflow->delegated_node))
518 			return;
519 
520 		/* the caller held the subflow bh socket lock */
521 		lockdep_assert_in_softirq();
522 
523 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
524 		schedule = list_empty(&delegated->head);
525 		list_add_tail(&subflow->delegated_node, &delegated->head);
526 		sock_hold(mptcp_subflow_tcp_sock(subflow));
527 		if (schedule)
528 			napi_schedule(&delegated->napi);
529 	}
530 }
531 
532 static inline struct mptcp_subflow_context *
533 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
534 {
535 	struct mptcp_subflow_context *ret;
536 
537 	if (list_empty(&delegated->head))
538 		return NULL;
539 
540 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
541 	list_del_init(&ret->delegated_node);
542 	return ret;
543 }
544 
545 static inline bool mptcp_subflow_has_delegated_action(const struct mptcp_subflow_context *subflow)
546 {
547 	return test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
548 }
549 
550 static inline void mptcp_subflow_delegated_done(struct mptcp_subflow_context *subflow)
551 {
552 	/* pairs with mptcp_subflow_delegate, ensures delegate_node is updated before
553 	 * touching the status bit
554 	 */
555 	smp_wmb();
556 	clear_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
557 }
558 
559 int mptcp_is_enabled(const struct net *net);
560 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
561 int mptcp_is_checksum_enabled(const struct net *net);
562 int mptcp_allow_join_id0(const struct net *net);
563 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
564 				     struct mptcp_options_received *mp_opt);
565 bool __mptcp_retransmit_pending_data(struct sock *sk);
566 bool mptcp_subflow_data_available(struct sock *sk);
567 void __init mptcp_subflow_init(void);
568 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
569 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
570 		     struct mptcp_subflow_context *subflow);
571 void mptcp_subflow_reset(struct sock *ssk);
572 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
573 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);
574 
575 /* called with sk socket lock held */
576 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
577 			    const struct mptcp_addr_info *remote,
578 			    u8 flags, int ifindex);
579 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
580 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
581 			 struct sockaddr_storage *addr,
582 			 unsigned short family);
583 
584 static inline bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
585 {
586 	struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
587 
588 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
589 	if (subflow->request_join && !subflow->fully_established)
590 		return false;
591 
592 	/* only send if our side has not closed yet */
593 	return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
594 }
595 
596 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
597 					      struct mptcp_subflow_context *ctx)
598 {
599 	sk->sk_data_ready = ctx->tcp_data_ready;
600 	sk->sk_state_change = ctx->tcp_state_change;
601 	sk->sk_write_space = ctx->tcp_write_space;
602 	sk->sk_error_report = ctx->tcp_error_report;
603 
604 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
605 }
606 
607 void __init mptcp_proto_init(void);
608 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
609 int __init mptcp_proto_v6_init(void);
610 #endif
611 
612 struct sock *mptcp_sk_clone(const struct sock *sk,
613 			    const struct mptcp_options_received *mp_opt,
614 			    struct request_sock *req);
615 void mptcp_get_options(const struct sock *sk,
616 		       const struct sk_buff *skb,
617 		       struct mptcp_options_received *mp_opt);
618 
619 void mptcp_finish_connect(struct sock *sk);
620 void __mptcp_set_connected(struct sock *sk);
621 static inline bool mptcp_is_fully_established(struct sock *sk)
622 {
623 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
624 	       READ_ONCE(mptcp_sk(sk)->fully_established);
625 }
626 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
627 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
628 bool mptcp_finish_join(struct sock *sk);
629 bool mptcp_schedule_work(struct sock *sk);
630 int mptcp_setsockopt(struct sock *sk, int level, int optname,
631 		     sockptr_t optval, unsigned int optlen);
632 int mptcp_getsockopt(struct sock *sk, int level, int optname,
633 		     char __user *optval, int __user *option);
634 
635 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
636 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
637 {
638 	if (use_64bit)
639 		return cur_seq;
640 
641 	return __mptcp_expand_seq(old_seq, cur_seq);
642 }
643 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
644 void __mptcp_data_acked(struct sock *sk);
645 void __mptcp_error_report(struct sock *sk);
646 void mptcp_subflow_eof(struct sock *sk);
647 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
648 void __mptcp_flush_join_list(struct mptcp_sock *msk);
649 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
650 {
651 	return READ_ONCE(msk->snd_data_fin_enable) &&
652 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
653 }
654 
655 static inline bool mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
656 {
657 	if ((sk->sk_userlocks & SOCK_SNDBUF_LOCK) || ssk->sk_sndbuf <= READ_ONCE(sk->sk_sndbuf))
658 		return false;
659 
660 	WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
661 	return true;
662 }
663 
664 static inline void mptcp_write_space(struct sock *sk)
665 {
666 	if (sk_stream_is_writeable(sk)) {
667 		/* pairs with memory barrier in mptcp_poll */
668 		smp_mb();
669 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
670 			sk_stream_write_space(sk);
671 	}
672 }
673 
674 void mptcp_destroy_common(struct mptcp_sock *msk);
675 
676 #define MPTCP_TOKEN_MAX_RETRIES	4
677 
678 void __init mptcp_token_init(void);
679 static inline void mptcp_token_init_request(struct request_sock *req)
680 {
681 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
682 }
683 
684 int mptcp_token_new_request(struct request_sock *req);
685 void mptcp_token_destroy_request(struct request_sock *req);
686 int mptcp_token_new_connect(struct sock *sk);
687 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
688 			struct mptcp_sock *msk);
689 bool mptcp_token_exists(u32 token);
690 struct mptcp_sock *mptcp_token_get_sock(u32 token);
691 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
692 					 long *s_num);
693 void mptcp_token_destroy(struct mptcp_sock *msk);
694 
695 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
696 
697 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
698 
699 void __init mptcp_pm_init(void);
700 void mptcp_pm_data_init(struct mptcp_sock *msk);
701 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
702 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
703 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk, gfp_t gfp);
704 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
705 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
706 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
707 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
708 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
709 				const struct mptcp_addr_info *addr);
710 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
711 			      struct mptcp_addr_info *addr);
712 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
713 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
714 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
715 			       const struct mptcp_rm_list *rm_list);
716 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
717 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
718 				 struct mptcp_addr_info *addr,
719 				 u8 bkup);
720 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
721 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
722 struct mptcp_pm_add_entry *
723 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
724 		       struct mptcp_addr_info *addr, bool check_id);
725 struct mptcp_pm_add_entry *
726 mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
727 				struct mptcp_addr_info *addr);
728 
729 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
730 			   const struct mptcp_addr_info *addr,
731 			   bool echo);
732 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
733 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
734 
735 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
736 		 const struct sock *ssk, gfp_t gfp);
737 void mptcp_event_addr_announced(const struct mptcp_sock *msk, const struct mptcp_addr_info *info);
738 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
739 
740 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
741 {
742 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
743 }
744 
745 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
746 {
747 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
748 }
749 
750 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
751 {
752 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
753 }
754 
755 static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
756 {
757 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
758 }
759 
760 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
761 {
762 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
763 }
764 
765 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
766 {
767 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
768 
769 	if (family == AF_INET6)
770 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
771 	if (!echo)
772 		len += MPTCPOPT_THMAC_LEN;
773 	/* account for 2 trailing 'nop' options */
774 	if (port)
775 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
776 
777 	return len;
778 }
779 
780 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
781 {
782 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
783 		return -EINVAL;
784 
785 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
786 }
787 
788 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
789 			      struct mptcp_addr_info *saddr, bool *echo, bool *port);
790 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
791 			     struct mptcp_rm_list *rm_list);
792 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
793 
794 void __init mptcp_pm_nl_init(void);
795 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
796 void mptcp_pm_nl_work(struct mptcp_sock *msk);
797 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
798 				     const struct mptcp_rm_list *rm_list);
799 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
800 unsigned int mptcp_pm_get_add_addr_signal_max(struct mptcp_sock *msk);
801 unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk);
802 unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk);
803 unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk);
804 
805 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
806 void mptcp_sockopt_sync_all(struct mptcp_sock *msk);
807 
808 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
809 {
810 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
811 }
812 
813 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
814 
815 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
816 {
817 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
818 }
819 
820 static inline bool mptcp_check_fallback(const struct sock *sk)
821 {
822 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
823 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
824 
825 	return __mptcp_check_fallback(msk);
826 }
827 
828 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
829 {
830 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
831 		pr_debug("TCP fallback already done (msk=%p)", msk);
832 		return;
833 	}
834 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
835 }
836 
837 static inline void mptcp_do_fallback(struct sock *sk)
838 {
839 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
840 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
841 
842 	__mptcp_do_fallback(msk);
843 }
844 
845 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
846 
847 static inline bool subflow_simultaneous_connect(struct sock *sk)
848 {
849 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
850 	struct sock *parent = subflow->conn;
851 
852 	return sk->sk_state == TCP_ESTABLISHED &&
853 	       !mptcp_sk(parent)->pm.server_side &&
854 	       !subflow->conn_finished;
855 }
856 
857 #ifdef CONFIG_SYN_COOKIES
858 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
859 				       struct sk_buff *skb);
860 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
861 					struct sk_buff *skb);
862 void __init mptcp_join_cookie_init(void);
863 #else
864 static inline void
865 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
866 				  struct sk_buff *skb) {}
867 static inline bool
868 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
869 				   struct sk_buff *skb)
870 {
871 	return false;
872 }
873 
874 static inline void mptcp_join_cookie_init(void) {}
875 #endif
876 
877 #endif /* __MPTCP_PROTOCOL_H */
878