xref: /linux/net/mptcp/protocol.h (revision d0f482bb06f9447d44d2cae0386a0bd768c3cc16)
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 
116 static inline bool before64(__u64 seq1, __u64 seq2)
117 {
118 	return (__s64)(seq1 - seq2) < 0;
119 }
120 
121 #define after64(seq2, seq1)	before64(seq1, seq2)
122 
123 struct mptcp_options_received {
124 	u64	sndr_key;
125 	u64	rcvr_key;
126 	u64	data_ack;
127 	u64	data_seq;
128 	u32	subflow_seq;
129 	u16	data_len;
130 	__sum16	csum;
131 	u16	mp_capable : 1,
132 		mp_join : 1,
133 		fastclose : 1,
134 		reset : 1,
135 		dss : 1,
136 		add_addr : 1,
137 		rm_addr : 1,
138 		mp_prio : 1,
139 		echo : 1,
140 		csum_reqd : 1,
141 		backup : 1,
142 		deny_join_id0 : 1;
143 	u32	token;
144 	u32	nonce;
145 	u64	thmac;
146 	u8	hmac[MPTCPOPT_HMAC_LEN];
147 	u8	join_id;
148 	u8	use_map:1,
149 		dsn64:1,
150 		data_fin:1,
151 		use_ack:1,
152 		ack64:1,
153 		mpc_map:1,
154 		__unused:2;
155 	struct mptcp_addr_info addr;
156 	struct mptcp_rm_list rm_list;
157 	u64	ahmac;
158 	u8	reset_reason:4;
159 	u8	reset_transient:1;
160 };
161 
162 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
163 {
164 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
165 		     ((nib & 0xF) << 8) | field);
166 }
167 
168 enum mptcp_pm_status {
169 	MPTCP_PM_ADD_ADDR_RECEIVED,
170 	MPTCP_PM_ADD_ADDR_SEND_ACK,
171 	MPTCP_PM_RM_ADDR_RECEIVED,
172 	MPTCP_PM_ESTABLISHED,
173 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
174 	MPTCP_PM_SUBFLOW_ESTABLISHED,
175 };
176 
177 enum mptcp_addr_signal_status {
178 	MPTCP_ADD_ADDR_SIGNAL,
179 	MPTCP_ADD_ADDR_ECHO,
180 	MPTCP_ADD_ADDR_IPV6,
181 	MPTCP_ADD_ADDR_PORT,
182 	MPTCP_RM_ADDR_SIGNAL,
183 };
184 
185 struct mptcp_pm_data {
186 	struct mptcp_addr_info local;
187 	struct mptcp_addr_info remote;
188 	struct list_head anno_list;
189 
190 	spinlock_t	lock;		/*protects the whole PM data */
191 
192 	u8		addr_signal;
193 	bool		server_side;
194 	bool		work_pending;
195 	bool		accept_addr;
196 	bool		accept_subflow;
197 	bool		remote_deny_join_id0;
198 	u8		add_addr_signaled;
199 	u8		add_addr_accepted;
200 	u8		local_addr_used;
201 	u8		subflows;
202 	u8		status;
203 	struct mptcp_rm_list rm_list_tx;
204 	struct mptcp_rm_list rm_list_rx;
205 };
206 
207 struct mptcp_data_frag {
208 	struct list_head list;
209 	u64 data_seq;
210 	u16 data_len;
211 	u16 offset;
212 	u16 overhead;
213 	u16 already_sent;
214 	struct page *page;
215 };
216 
217 /* MPTCP connection sock */
218 struct mptcp_sock {
219 	/* inet_connection_sock must be the first member */
220 	struct inet_connection_sock sk;
221 	u64		local_key;
222 	u64		remote_key;
223 	u64		write_seq;
224 	u64		snd_nxt;
225 	u64		ack_seq;
226 	u64		rcv_wnd_sent;
227 	u64		rcv_data_fin_seq;
228 	int		wmem_reserved;
229 	struct sock	*last_snd;
230 	int		snd_burst;
231 	int		old_wspace;
232 	u64		snd_una;
233 	u64		wnd_end;
234 	unsigned long	timer_ival;
235 	u32		token;
236 	int		rmem_released;
237 	unsigned long	flags;
238 	bool		can_ack;
239 	bool		fully_established;
240 	bool		rcv_data_fin;
241 	bool		snd_data_fin_enable;
242 	bool		rcv_fastclose;
243 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
244 	bool		csum_enabled;
245 	spinlock_t	join_list_lock;
246 	struct work_struct work;
247 	struct sk_buff  *ooo_last_skb;
248 	struct rb_root  out_of_order_queue;
249 	struct sk_buff_head receive_queue;
250 	int		tx_pending_data;
251 	struct list_head conn_list;
252 	struct list_head rtx_queue;
253 	struct mptcp_data_frag *first_pending;
254 	struct list_head join_list;
255 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
256 	struct sock	*first;
257 	struct mptcp_pm_data	pm;
258 	struct {
259 		u32	space;	/* bytes copied in last measurement window */
260 		u32	copied; /* bytes copied in this measurement window */
261 		u64	time;	/* start time of measurement window */
262 		u64	rtt_us; /* last maximum rtt of subflows */
263 	} rcvq_space;
264 
265 	u32 setsockopt_seq;
266 	char		ca_name[TCP_CA_NAME_MAX];
267 };
268 
269 #define mptcp_lock_sock(___sk, cb) do {					\
270 	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
271 	might_sleep();							\
272 	spin_lock_bh(&__sk->sk_lock.slock);				\
273 	if (__sk->sk_lock.owned)					\
274 		__lock_sock(__sk);					\
275 	cb;								\
276 	__sk->sk_lock.owned = 1;					\
277 	spin_unlock(&__sk->sk_lock.slock);				\
278 	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
279 	local_bh_enable();						\
280 } while (0)
281 
282 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
283 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
284 
285 #define mptcp_for_each_subflow(__msk, __subflow)			\
286 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
287 
288 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
289 {
290 	sock_owned_by_me((const struct sock *)msk);
291 }
292 
293 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
294 {
295 	return (struct mptcp_sock *)sk;
296 }
297 
298 static inline int __mptcp_space(const struct sock *sk)
299 {
300 	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released);
301 }
302 
303 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
304 {
305 	const struct mptcp_sock *msk = mptcp_sk(sk);
306 
307 	return READ_ONCE(msk->first_pending);
308 }
309 
310 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
311 {
312 	struct mptcp_sock *msk = mptcp_sk(sk);
313 	struct mptcp_data_frag *cur;
314 
315 	cur = msk->first_pending;
316 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
317 						     list_next_entry(cur, list);
318 }
319 
320 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
321 {
322 	struct mptcp_sock *msk = mptcp_sk(sk);
323 
324 	if (!msk->first_pending)
325 		return NULL;
326 
327 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
328 		return NULL;
329 
330 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
331 }
332 
333 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
334 {
335 	struct mptcp_sock *msk = mptcp_sk(sk);
336 
337 	if (msk->snd_una == READ_ONCE(msk->snd_nxt))
338 		return NULL;
339 
340 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
341 }
342 
343 struct csum_pseudo_header {
344 	__be64 data_seq;
345 	__be32 subflow_seq;
346 	__be16 data_len;
347 	__sum16 csum;
348 };
349 
350 struct mptcp_subflow_request_sock {
351 	struct	tcp_request_sock sk;
352 	u16	mp_capable : 1,
353 		mp_join : 1,
354 		backup : 1,
355 		csum_reqd : 1,
356 		allow_join_id0 : 1;
357 	u8	local_id;
358 	u8	remote_id;
359 	u64	local_key;
360 	u64	idsn;
361 	u32	token;
362 	u32	ssn_offset;
363 	u64	thmac;
364 	u32	local_nonce;
365 	u32	remote_nonce;
366 	struct mptcp_sock	*msk;
367 	struct hlist_nulls_node token_node;
368 };
369 
370 static inline struct mptcp_subflow_request_sock *
371 mptcp_subflow_rsk(const struct request_sock *rsk)
372 {
373 	return (struct mptcp_subflow_request_sock *)rsk;
374 }
375 
376 enum mptcp_data_avail {
377 	MPTCP_SUBFLOW_NODATA,
378 	MPTCP_SUBFLOW_DATA_AVAIL,
379 };
380 
381 struct mptcp_delegated_action {
382 	struct napi_struct napi;
383 	struct list_head head;
384 };
385 
386 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
387 
388 #define MPTCP_DELEGATE_SEND		0
389 
390 /* MPTCP subflow context */
391 struct mptcp_subflow_context {
392 	struct	list_head node;/* conn_list of subflows */
393 	u64	local_key;
394 	u64	remote_key;
395 	u64	idsn;
396 	u64	map_seq;
397 	u32	snd_isn;
398 	u32	token;
399 	u32	rel_write_seq;
400 	u32	map_subflow_seq;
401 	u32	ssn_offset;
402 	u32	map_data_len;
403 	__wsum	map_data_csum;
404 	u32	map_csum_len;
405 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
406 		request_join : 1,   /* send MP_JOIN */
407 		request_bkup : 1,
408 		mp_capable : 1,	    /* remote is MPTCP capable */
409 		mp_join : 1,	    /* remote is JOINing */
410 		fully_established : 1,	    /* path validated */
411 		pm_notified : 1,    /* PM hook called for established status */
412 		conn_finished : 1,
413 		map_valid : 1,
414 		map_csum_reqd : 1,
415 		map_data_fin : 1,
416 		mpc_map : 1,
417 		backup : 1,
418 		send_mp_prio : 1,
419 		rx_eof : 1,
420 		can_ack : 1,        /* only after processing the remote a key */
421 		disposable : 1;	    /* ctx can be free at ulp release time */
422 	enum mptcp_data_avail data_avail;
423 	u32	remote_nonce;
424 	u64	thmac;
425 	u32	local_nonce;
426 	u32	remote_token;
427 	u8	hmac[MPTCPOPT_HMAC_LEN];
428 	u8	local_id;
429 	u8	remote_id;
430 	u8	reset_seen:1;
431 	u8	reset_transient:1;
432 	u8	reset_reason:4;
433 
434 	long	delegated_status;
435 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
436 
437 	u32 setsockopt_seq;
438 
439 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
440 	struct	sock *conn;	    /* parent mptcp_sock */
441 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
442 	void	(*tcp_data_ready)(struct sock *sk);
443 	void	(*tcp_state_change)(struct sock *sk);
444 	void	(*tcp_write_space)(struct sock *sk);
445 	void	(*tcp_error_report)(struct sock *sk);
446 
447 	struct	rcu_head rcu;
448 };
449 
450 static inline struct mptcp_subflow_context *
451 mptcp_subflow_ctx(const struct sock *sk)
452 {
453 	struct inet_connection_sock *icsk = inet_csk(sk);
454 
455 	/* Use RCU on icsk_ulp_data only for sock diag code */
456 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
457 }
458 
459 static inline struct sock *
460 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
461 {
462 	return subflow->tcp_sock;
463 }
464 
465 static inline u64
466 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
467 {
468 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
469 		      subflow->ssn_offset -
470 		      subflow->map_subflow_seq;
471 }
472 
473 static inline u64
474 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
475 {
476 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
477 }
478 
479 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
480 					     struct mptcp_subflow_context *subflow)
481 {
482 	sock_hold(mptcp_subflow_tcp_sock(subflow));
483 	spin_lock_bh(&msk->join_list_lock);
484 	list_add_tail(&subflow->node, &msk->join_list);
485 	spin_unlock_bh(&msk->join_list_lock);
486 }
487 
488 void mptcp_subflow_process_delegated(struct sock *ssk);
489 
490 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow)
491 {
492 	struct mptcp_delegated_action *delegated;
493 	bool schedule;
494 
495 	/* The implied barrier pairs with mptcp_subflow_delegated_done(), and
496 	 * ensures the below list check sees list updates done prior to status
497 	 * bit changes
498 	 */
499 	if (!test_and_set_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
500 		/* still on delegated list from previous scheduling */
501 		if (!list_empty(&subflow->delegated_node))
502 			return;
503 
504 		/* the caller held the subflow bh socket lock */
505 		lockdep_assert_in_softirq();
506 
507 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
508 		schedule = list_empty(&delegated->head);
509 		list_add_tail(&subflow->delegated_node, &delegated->head);
510 		sock_hold(mptcp_subflow_tcp_sock(subflow));
511 		if (schedule)
512 			napi_schedule(&delegated->napi);
513 	}
514 }
515 
516 static inline struct mptcp_subflow_context *
517 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
518 {
519 	struct mptcp_subflow_context *ret;
520 
521 	if (list_empty(&delegated->head))
522 		return NULL;
523 
524 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
525 	list_del_init(&ret->delegated_node);
526 	return ret;
527 }
528 
529 static inline bool mptcp_subflow_has_delegated_action(const struct mptcp_subflow_context *subflow)
530 {
531 	return test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
532 }
533 
534 static inline void mptcp_subflow_delegated_done(struct mptcp_subflow_context *subflow)
535 {
536 	/* pairs with mptcp_subflow_delegate, ensures delegate_node is updated before
537 	 * touching the status bit
538 	 */
539 	smp_wmb();
540 	clear_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
541 }
542 
543 int mptcp_is_enabled(struct net *net);
544 unsigned int mptcp_get_add_addr_timeout(struct net *net);
545 int mptcp_is_checksum_enabled(struct net *net);
546 int mptcp_allow_join_id0(struct net *net);
547 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
548 				     struct mptcp_options_received *mp_opt);
549 bool mptcp_subflow_data_available(struct sock *sk);
550 void __init mptcp_subflow_init(void);
551 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
552 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
553 		     struct mptcp_subflow_context *subflow);
554 void mptcp_subflow_reset(struct sock *ssk);
555 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
556 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);
557 
558 /* called with sk socket lock held */
559 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
560 			    const struct mptcp_addr_info *remote,
561 			    u8 flags, int ifindex);
562 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
563 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
564 			 struct sockaddr_storage *addr,
565 			 unsigned short family);
566 
567 static inline bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
568 {
569 	struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
570 
571 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
572 	if (subflow->request_join && !subflow->fully_established)
573 		return false;
574 
575 	/* only send if our side has not closed yet */
576 	return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
577 }
578 
579 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
580 					      struct mptcp_subflow_context *ctx)
581 {
582 	sk->sk_data_ready = ctx->tcp_data_ready;
583 	sk->sk_state_change = ctx->tcp_state_change;
584 	sk->sk_write_space = ctx->tcp_write_space;
585 	sk->sk_error_report = ctx->tcp_error_report;
586 
587 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
588 }
589 
590 void __init mptcp_proto_init(void);
591 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
592 int __init mptcp_proto_v6_init(void);
593 #endif
594 
595 struct sock *mptcp_sk_clone(const struct sock *sk,
596 			    const struct mptcp_options_received *mp_opt,
597 			    struct request_sock *req);
598 void mptcp_get_options(const struct sock *sk,
599 		       const struct sk_buff *skb,
600 		       struct mptcp_options_received *mp_opt);
601 
602 void mptcp_finish_connect(struct sock *sk);
603 static inline bool mptcp_is_fully_established(struct sock *sk)
604 {
605 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
606 	       READ_ONCE(mptcp_sk(sk)->fully_established);
607 }
608 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
609 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
610 bool mptcp_finish_join(struct sock *sk);
611 bool mptcp_schedule_work(struct sock *sk);
612 int mptcp_setsockopt(struct sock *sk, int level, int optname,
613 		     sockptr_t optval, unsigned int optlen);
614 int mptcp_getsockopt(struct sock *sk, int level, int optname,
615 		     char __user *optval, int __user *option);
616 
617 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
618 void __mptcp_data_acked(struct sock *sk);
619 void __mptcp_error_report(struct sock *sk);
620 void mptcp_subflow_eof(struct sock *sk);
621 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
622 void __mptcp_flush_join_list(struct mptcp_sock *msk);
623 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
624 {
625 	return READ_ONCE(msk->snd_data_fin_enable) &&
626 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
627 }
628 
629 static inline bool mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
630 {
631 	if ((sk->sk_userlocks & SOCK_SNDBUF_LOCK) || ssk->sk_sndbuf <= READ_ONCE(sk->sk_sndbuf))
632 		return false;
633 
634 	WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
635 	return true;
636 }
637 
638 static inline void mptcp_write_space(struct sock *sk)
639 {
640 	if (sk_stream_is_writeable(sk)) {
641 		/* pairs with memory barrier in mptcp_poll */
642 		smp_mb();
643 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
644 			sk_stream_write_space(sk);
645 	}
646 }
647 
648 void mptcp_destroy_common(struct mptcp_sock *msk);
649 
650 #define MPTCP_TOKEN_MAX_RETRIES	4
651 
652 void __init mptcp_token_init(void);
653 static inline void mptcp_token_init_request(struct request_sock *req)
654 {
655 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
656 }
657 
658 int mptcp_token_new_request(struct request_sock *req);
659 void mptcp_token_destroy_request(struct request_sock *req);
660 int mptcp_token_new_connect(struct sock *sk);
661 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
662 			struct mptcp_sock *msk);
663 bool mptcp_token_exists(u32 token);
664 struct mptcp_sock *mptcp_token_get_sock(u32 token);
665 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
666 					 long *s_num);
667 void mptcp_token_destroy(struct mptcp_sock *msk);
668 
669 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
670 
671 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
672 
673 void __init mptcp_pm_init(void);
674 void mptcp_pm_data_init(struct mptcp_sock *msk);
675 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
676 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk, gfp_t gfp);
677 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
678 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
679 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
680 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
681 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
682 				const struct mptcp_addr_info *addr);
683 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
684 			      struct mptcp_addr_info *addr);
685 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
686 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
687 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
688 			       const struct mptcp_rm_list *rm_list);
689 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
690 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
691 				 struct mptcp_addr_info *addr,
692 				 u8 bkup);
693 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
694 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
695 struct mptcp_pm_add_entry *
696 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
697 		       struct mptcp_addr_info *addr, bool check_id);
698 struct mptcp_pm_add_entry *
699 mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
700 				struct mptcp_addr_info *addr);
701 
702 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
703 			   const struct mptcp_addr_info *addr,
704 			   bool echo);
705 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
706 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
707 
708 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
709 		 const struct sock *ssk, gfp_t gfp);
710 void mptcp_event_addr_announced(const struct mptcp_sock *msk, const struct mptcp_addr_info *info);
711 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
712 
713 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
714 {
715 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
716 }
717 
718 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
719 {
720 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
721 }
722 
723 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
724 {
725 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
726 }
727 
728 static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
729 {
730 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
731 }
732 
733 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
734 {
735 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
736 }
737 
738 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
739 {
740 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
741 
742 	if (family == AF_INET6)
743 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
744 	if (!echo)
745 		len += MPTCPOPT_THMAC_LEN;
746 	/* account for 2 trailing 'nop' options */
747 	if (port)
748 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
749 
750 	return len;
751 }
752 
753 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
754 {
755 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
756 		return -EINVAL;
757 
758 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
759 }
760 
761 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
762 			      struct mptcp_addr_info *saddr, bool *echo, bool *port);
763 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
764 			     struct mptcp_rm_list *rm_list);
765 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
766 
767 void __init mptcp_pm_nl_init(void);
768 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
769 void mptcp_pm_nl_work(struct mptcp_sock *msk);
770 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
771 				     const struct mptcp_rm_list *rm_list);
772 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
773 unsigned int mptcp_pm_get_add_addr_signal_max(struct mptcp_sock *msk);
774 unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk);
775 unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk);
776 unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk);
777 
778 int mptcp_setsockopt(struct sock *sk, int level, int optname,
779 		     sockptr_t optval, unsigned int optlen);
780 
781 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
782 void mptcp_sockopt_sync_all(struct mptcp_sock *msk);
783 
784 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
785 {
786 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
787 }
788 
789 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
790 
791 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
792 {
793 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
794 }
795 
796 static inline bool mptcp_check_fallback(const struct sock *sk)
797 {
798 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
799 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
800 
801 	return __mptcp_check_fallback(msk);
802 }
803 
804 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
805 {
806 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
807 		pr_debug("TCP fallback already done (msk=%p)", msk);
808 		return;
809 	}
810 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
811 }
812 
813 static inline void mptcp_do_fallback(struct sock *sk)
814 {
815 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
816 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
817 
818 	__mptcp_do_fallback(msk);
819 }
820 
821 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
822 
823 static inline bool subflow_simultaneous_connect(struct sock *sk)
824 {
825 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
826 	struct sock *parent = subflow->conn;
827 
828 	return sk->sk_state == TCP_ESTABLISHED &&
829 	       !mptcp_sk(parent)->pm.server_side &&
830 	       !subflow->conn_finished;
831 }
832 
833 #ifdef CONFIG_SYN_COOKIES
834 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
835 				       struct sk_buff *skb);
836 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
837 					struct sk_buff *skb);
838 void __init mptcp_join_cookie_init(void);
839 #else
840 static inline void
841 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
842 				  struct sk_buff *skb) {}
843 static inline bool
844 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
845 				   struct sk_buff *skb)
846 {
847 	return false;
848 }
849 
850 static inline void mptcp_join_cookie_init(void) {}
851 #endif
852 
853 #endif /* __MPTCP_PROTOCOL_H */
854