xref: /openbmc/linux/net/mptcp/protocol.h (revision aa0dc6a7)
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		snd_una;
234 	u64		wnd_end;
235 	unsigned long	timer_ival;
236 	u32		token;
237 	int		rmem_released;
238 	unsigned long	flags;
239 	bool		can_ack;
240 	bool		fully_established;
241 	bool		rcv_data_fin;
242 	bool		snd_data_fin_enable;
243 	bool		rcv_fastclose;
244 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
245 	bool		csum_enabled;
246 	spinlock_t	join_list_lock;
247 	struct work_struct work;
248 	struct sk_buff  *ooo_last_skb;
249 	struct rb_root  out_of_order_queue;
250 	struct sk_buff_head receive_queue;
251 	int		tx_pending_data;
252 	struct list_head conn_list;
253 	struct list_head rtx_queue;
254 	struct mptcp_data_frag *first_pending;
255 	struct list_head join_list;
256 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
257 	struct sock	*first;
258 	struct mptcp_pm_data	pm;
259 	struct {
260 		u32	space;	/* bytes copied in last measurement window */
261 		u32	copied; /* bytes copied in this measurement window */
262 		u64	time;	/* start time of measurement window */
263 		u64	rtt_us; /* last maximum rtt of subflows */
264 	} rcvq_space;
265 
266 	u32 setsockopt_seq;
267 	char		ca_name[TCP_CA_NAME_MAX];
268 };
269 
270 #define mptcp_lock_sock(___sk, cb) do {					\
271 	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
272 	might_sleep();							\
273 	spin_lock_bh(&__sk->sk_lock.slock);				\
274 	if (__sk->sk_lock.owned)					\
275 		__lock_sock(__sk);					\
276 	cb;								\
277 	__sk->sk_lock.owned = 1;					\
278 	spin_unlock(&__sk->sk_lock.slock);				\
279 	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
280 	local_bh_enable();						\
281 } while (0)
282 
283 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
284 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
285 
286 #define mptcp_for_each_subflow(__msk, __subflow)			\
287 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
288 
289 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
290 {
291 	sock_owned_by_me((const struct sock *)msk);
292 }
293 
294 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
295 {
296 	return (struct mptcp_sock *)sk;
297 }
298 
299 static inline int __mptcp_space(const struct sock *sk)
300 {
301 	return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released);
302 }
303 
304 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
305 {
306 	const struct mptcp_sock *msk = mptcp_sk(sk);
307 
308 	return READ_ONCE(msk->first_pending);
309 }
310 
311 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
312 {
313 	struct mptcp_sock *msk = mptcp_sk(sk);
314 	struct mptcp_data_frag *cur;
315 
316 	cur = msk->first_pending;
317 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
318 						     list_next_entry(cur, list);
319 }
320 
321 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
322 {
323 	struct mptcp_sock *msk = mptcp_sk(sk);
324 
325 	if (!msk->first_pending)
326 		return NULL;
327 
328 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
329 		return NULL;
330 
331 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
332 }
333 
334 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
335 {
336 	struct mptcp_sock *msk = mptcp_sk(sk);
337 
338 	if (msk->snd_una == READ_ONCE(msk->snd_nxt))
339 		return NULL;
340 
341 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
342 }
343 
344 struct csum_pseudo_header {
345 	__be64 data_seq;
346 	__be32 subflow_seq;
347 	__be16 data_len;
348 	__sum16 csum;
349 };
350 
351 struct mptcp_subflow_request_sock {
352 	struct	tcp_request_sock sk;
353 	u16	mp_capable : 1,
354 		mp_join : 1,
355 		backup : 1,
356 		csum_reqd : 1,
357 		allow_join_id0 : 1;
358 	u8	local_id;
359 	u8	remote_id;
360 	u64	local_key;
361 	u64	idsn;
362 	u32	token;
363 	u32	ssn_offset;
364 	u64	thmac;
365 	u32	local_nonce;
366 	u32	remote_nonce;
367 	struct mptcp_sock	*msk;
368 	struct hlist_nulls_node token_node;
369 };
370 
371 static inline struct mptcp_subflow_request_sock *
372 mptcp_subflow_rsk(const struct request_sock *rsk)
373 {
374 	return (struct mptcp_subflow_request_sock *)rsk;
375 }
376 
377 enum mptcp_data_avail {
378 	MPTCP_SUBFLOW_NODATA,
379 	MPTCP_SUBFLOW_DATA_AVAIL,
380 };
381 
382 struct mptcp_delegated_action {
383 	struct napi_struct napi;
384 	struct list_head head;
385 };
386 
387 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
388 
389 #define MPTCP_DELEGATE_SEND		0
390 
391 /* MPTCP subflow context */
392 struct mptcp_subflow_context {
393 	struct	list_head node;/* conn_list of subflows */
394 	u64	local_key;
395 	u64	remote_key;
396 	u64	idsn;
397 	u64	map_seq;
398 	u32	snd_isn;
399 	u32	token;
400 	u32	rel_write_seq;
401 	u32	map_subflow_seq;
402 	u32	ssn_offset;
403 	u32	map_data_len;
404 	__wsum	map_data_csum;
405 	u32	map_csum_len;
406 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
407 		request_join : 1,   /* send MP_JOIN */
408 		request_bkup : 1,
409 		mp_capable : 1,	    /* remote is MPTCP capable */
410 		mp_join : 1,	    /* remote is JOINing */
411 		fully_established : 1,	    /* path validated */
412 		pm_notified : 1,    /* PM hook called for established status */
413 		conn_finished : 1,
414 		map_valid : 1,
415 		map_csum_reqd : 1,
416 		map_data_fin : 1,
417 		mpc_map : 1,
418 		backup : 1,
419 		send_mp_prio : 1,
420 		rx_eof : 1,
421 		can_ack : 1,        /* only after processing the remote a key */
422 		disposable : 1;	    /* ctx can be free at ulp release time */
423 	enum mptcp_data_avail data_avail;
424 	u32	remote_nonce;
425 	u64	thmac;
426 	u32	local_nonce;
427 	u32	remote_token;
428 	u8	hmac[MPTCPOPT_HMAC_LEN];
429 	u8	local_id;
430 	u8	remote_id;
431 	u8	reset_seen:1;
432 	u8	reset_transient:1;
433 	u8	reset_reason:4;
434 
435 	long	delegated_status;
436 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
437 
438 	u32 setsockopt_seq;
439 
440 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
441 	struct	sock *conn;	    /* parent mptcp_sock */
442 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
443 	void	(*tcp_data_ready)(struct sock *sk);
444 	void	(*tcp_state_change)(struct sock *sk);
445 	void	(*tcp_write_space)(struct sock *sk);
446 	void	(*tcp_error_report)(struct sock *sk);
447 
448 	struct	rcu_head rcu;
449 };
450 
451 static inline struct mptcp_subflow_context *
452 mptcp_subflow_ctx(const struct sock *sk)
453 {
454 	struct inet_connection_sock *icsk = inet_csk(sk);
455 
456 	/* Use RCU on icsk_ulp_data only for sock diag code */
457 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
458 }
459 
460 static inline struct sock *
461 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
462 {
463 	return subflow->tcp_sock;
464 }
465 
466 static inline u64
467 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
468 {
469 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
470 		      subflow->ssn_offset -
471 		      subflow->map_subflow_seq;
472 }
473 
474 static inline u64
475 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
476 {
477 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
478 }
479 
480 static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
481 					     struct mptcp_subflow_context *subflow)
482 {
483 	sock_hold(mptcp_subflow_tcp_sock(subflow));
484 	spin_lock_bh(&msk->join_list_lock);
485 	list_add_tail(&subflow->node, &msk->join_list);
486 	spin_unlock_bh(&msk->join_list_lock);
487 }
488 
489 void mptcp_subflow_process_delegated(struct sock *ssk);
490 
491 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow)
492 {
493 	struct mptcp_delegated_action *delegated;
494 	bool schedule;
495 
496 	/* The implied barrier pairs with mptcp_subflow_delegated_done(), and
497 	 * ensures the below list check sees list updates done prior to status
498 	 * bit changes
499 	 */
500 	if (!test_and_set_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
501 		/* still on delegated list from previous scheduling */
502 		if (!list_empty(&subflow->delegated_node))
503 			return;
504 
505 		/* the caller held the subflow bh socket lock */
506 		lockdep_assert_in_softirq();
507 
508 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
509 		schedule = list_empty(&delegated->head);
510 		list_add_tail(&subflow->delegated_node, &delegated->head);
511 		sock_hold(mptcp_subflow_tcp_sock(subflow));
512 		if (schedule)
513 			napi_schedule(&delegated->napi);
514 	}
515 }
516 
517 static inline struct mptcp_subflow_context *
518 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
519 {
520 	struct mptcp_subflow_context *ret;
521 
522 	if (list_empty(&delegated->head))
523 		return NULL;
524 
525 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
526 	list_del_init(&ret->delegated_node);
527 	return ret;
528 }
529 
530 static inline bool mptcp_subflow_has_delegated_action(const struct mptcp_subflow_context *subflow)
531 {
532 	return test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
533 }
534 
535 static inline void mptcp_subflow_delegated_done(struct mptcp_subflow_context *subflow)
536 {
537 	/* pairs with mptcp_subflow_delegate, ensures delegate_node is updated before
538 	 * touching the status bit
539 	 */
540 	smp_wmb();
541 	clear_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
542 }
543 
544 int mptcp_is_enabled(struct net *net);
545 unsigned int mptcp_get_add_addr_timeout(struct net *net);
546 int mptcp_is_checksum_enabled(struct net *net);
547 int mptcp_allow_join_id0(struct net *net);
548 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
549 				     struct mptcp_options_received *mp_opt);
550 bool mptcp_subflow_data_available(struct sock *sk);
551 void __init mptcp_subflow_init(void);
552 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
553 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
554 		     struct mptcp_subflow_context *subflow);
555 void mptcp_subflow_reset(struct sock *ssk);
556 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
557 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);
558 
559 /* called with sk socket lock held */
560 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
561 			    const struct mptcp_addr_info *remote,
562 			    u8 flags, int ifindex);
563 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
564 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
565 			 struct sockaddr_storage *addr,
566 			 unsigned short family);
567 
568 static inline bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
569 {
570 	struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
571 
572 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
573 	if (subflow->request_join && !subflow->fully_established)
574 		return false;
575 
576 	/* only send if our side has not closed yet */
577 	return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
578 }
579 
580 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
581 					      struct mptcp_subflow_context *ctx)
582 {
583 	sk->sk_data_ready = ctx->tcp_data_ready;
584 	sk->sk_state_change = ctx->tcp_state_change;
585 	sk->sk_write_space = ctx->tcp_write_space;
586 	sk->sk_error_report = ctx->tcp_error_report;
587 
588 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
589 }
590 
591 void __init mptcp_proto_init(void);
592 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
593 int __init mptcp_proto_v6_init(void);
594 #endif
595 
596 struct sock *mptcp_sk_clone(const struct sock *sk,
597 			    const struct mptcp_options_received *mp_opt,
598 			    struct request_sock *req);
599 void mptcp_get_options(const struct sock *sk,
600 		       const struct sk_buff *skb,
601 		       struct mptcp_options_received *mp_opt);
602 
603 void mptcp_finish_connect(struct sock *sk);
604 void __mptcp_set_connected(struct sock *sk);
605 static inline bool mptcp_is_fully_established(struct sock *sk)
606 {
607 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
608 	       READ_ONCE(mptcp_sk(sk)->fully_established);
609 }
610 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
611 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
612 bool mptcp_finish_join(struct sock *sk);
613 bool mptcp_schedule_work(struct sock *sk);
614 int mptcp_setsockopt(struct sock *sk, int level, int optname,
615 		     sockptr_t optval, unsigned int optlen);
616 int mptcp_getsockopt(struct sock *sk, int level, int optname,
617 		     char __user *optval, int __user *option);
618 
619 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
620 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
621 {
622 	if (use_64bit)
623 		return cur_seq;
624 
625 	return __mptcp_expand_seq(old_seq, cur_seq);
626 }
627 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
628 void __mptcp_data_acked(struct sock *sk);
629 void __mptcp_error_report(struct sock *sk);
630 void mptcp_subflow_eof(struct sock *sk);
631 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
632 void __mptcp_flush_join_list(struct mptcp_sock *msk);
633 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
634 {
635 	return READ_ONCE(msk->snd_data_fin_enable) &&
636 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
637 }
638 
639 static inline bool mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
640 {
641 	if ((sk->sk_userlocks & SOCK_SNDBUF_LOCK) || ssk->sk_sndbuf <= READ_ONCE(sk->sk_sndbuf))
642 		return false;
643 
644 	WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
645 	return true;
646 }
647 
648 static inline void mptcp_write_space(struct sock *sk)
649 {
650 	if (sk_stream_is_writeable(sk)) {
651 		/* pairs with memory barrier in mptcp_poll */
652 		smp_mb();
653 		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
654 			sk_stream_write_space(sk);
655 	}
656 }
657 
658 void mptcp_destroy_common(struct mptcp_sock *msk);
659 
660 #define MPTCP_TOKEN_MAX_RETRIES	4
661 
662 void __init mptcp_token_init(void);
663 static inline void mptcp_token_init_request(struct request_sock *req)
664 {
665 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
666 }
667 
668 int mptcp_token_new_request(struct request_sock *req);
669 void mptcp_token_destroy_request(struct request_sock *req);
670 int mptcp_token_new_connect(struct sock *sk);
671 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
672 			struct mptcp_sock *msk);
673 bool mptcp_token_exists(u32 token);
674 struct mptcp_sock *mptcp_token_get_sock(u32 token);
675 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
676 					 long *s_num);
677 void mptcp_token_destroy(struct mptcp_sock *msk);
678 
679 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
680 
681 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
682 
683 void __init mptcp_pm_init(void);
684 void mptcp_pm_data_init(struct mptcp_sock *msk);
685 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
686 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk, gfp_t gfp);
687 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
688 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
689 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
690 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
691 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
692 				const struct mptcp_addr_info *addr);
693 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
694 			      struct mptcp_addr_info *addr);
695 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
696 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
697 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
698 			       const struct mptcp_rm_list *rm_list);
699 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
700 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
701 				 struct mptcp_addr_info *addr,
702 				 u8 bkup);
703 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
704 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
705 struct mptcp_pm_add_entry *
706 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
707 		       struct mptcp_addr_info *addr, bool check_id);
708 struct mptcp_pm_add_entry *
709 mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
710 				struct mptcp_addr_info *addr);
711 
712 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
713 			   const struct mptcp_addr_info *addr,
714 			   bool echo);
715 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
716 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
717 
718 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
719 		 const struct sock *ssk, gfp_t gfp);
720 void mptcp_event_addr_announced(const struct mptcp_sock *msk, const struct mptcp_addr_info *info);
721 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
722 
723 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
724 {
725 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
726 }
727 
728 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
729 {
730 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
731 }
732 
733 static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
734 {
735 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
736 }
737 
738 static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
739 {
740 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
741 }
742 
743 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
744 {
745 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
746 }
747 
748 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
749 {
750 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
751 
752 	if (family == AF_INET6)
753 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
754 	if (!echo)
755 		len += MPTCPOPT_THMAC_LEN;
756 	/* account for 2 trailing 'nop' options */
757 	if (port)
758 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
759 
760 	return len;
761 }
762 
763 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
764 {
765 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
766 		return -EINVAL;
767 
768 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
769 }
770 
771 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
772 			      struct mptcp_addr_info *saddr, bool *echo, bool *port);
773 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
774 			     struct mptcp_rm_list *rm_list);
775 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
776 
777 void __init mptcp_pm_nl_init(void);
778 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
779 void mptcp_pm_nl_work(struct mptcp_sock *msk);
780 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
781 				     const struct mptcp_rm_list *rm_list);
782 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
783 unsigned int mptcp_pm_get_add_addr_signal_max(struct mptcp_sock *msk);
784 unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk);
785 unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk);
786 unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk);
787 
788 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
789 void mptcp_sockopt_sync_all(struct mptcp_sock *msk);
790 
791 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
792 {
793 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
794 }
795 
796 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
797 
798 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
799 {
800 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
801 }
802 
803 static inline bool mptcp_check_fallback(const struct sock *sk)
804 {
805 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
806 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
807 
808 	return __mptcp_check_fallback(msk);
809 }
810 
811 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
812 {
813 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
814 		pr_debug("TCP fallback already done (msk=%p)", msk);
815 		return;
816 	}
817 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
818 }
819 
820 static inline void mptcp_do_fallback(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 	__mptcp_do_fallback(msk);
826 }
827 
828 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
829 
830 static inline bool subflow_simultaneous_connect(struct sock *sk)
831 {
832 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
833 	struct sock *parent = subflow->conn;
834 
835 	return sk->sk_state == TCP_ESTABLISHED &&
836 	       !mptcp_sk(parent)->pm.server_side &&
837 	       !subflow->conn_finished;
838 }
839 
840 #ifdef CONFIG_SYN_COOKIES
841 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
842 				       struct sk_buff *skb);
843 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
844 					struct sk_buff *skb);
845 void __init mptcp_join_cookie_init(void);
846 #else
847 static inline void
848 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
849 				  struct sk_buff *skb) {}
850 static inline bool
851 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
852 				   struct sk_buff *skb)
853 {
854 	return false;
855 }
856 
857 static inline void mptcp_join_cookie_init(void) {}
858 #endif
859 
860 #endif /* __MPTCP_PROTOCOL_H */
861