xref: /linux/net/mptcp/protocol.h (revision a06c3fad49a50d5d5eb078f93e70f4d3eca5d5a5)
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 #include <net/genetlink.h>
15 #include <net/rstreason.h>
16 
17 #define MPTCP_SUPPORTED_VERSION	1
18 
19 /* MPTCP option bits */
20 #define OPTION_MPTCP_MPC_SYN	BIT(0)
21 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
22 #define OPTION_MPTCP_MPC_ACK	BIT(2)
23 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
24 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
25 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
26 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
27 #define OPTION_MPTCP_RM_ADDR	BIT(7)
28 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
29 #define OPTION_MPTCP_PRIO	BIT(9)
30 #define OPTION_MPTCP_RST	BIT(10)
31 #define OPTION_MPTCP_DSS	BIT(11)
32 #define OPTION_MPTCP_FAIL	BIT(12)
33 
34 #define OPTION_MPTCP_CSUMREQD	BIT(13)
35 
36 #define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
37 				 OPTION_MPTCP_MPC_ACK)
38 #define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
39 				 OPTION_MPTCP_MPJ_ACK)
40 
41 /* MPTCP option subtypes */
42 #define MPTCPOPT_MP_CAPABLE	0
43 #define MPTCPOPT_MP_JOIN	1
44 #define MPTCPOPT_DSS		2
45 #define MPTCPOPT_ADD_ADDR	3
46 #define MPTCPOPT_RM_ADDR	4
47 #define MPTCPOPT_MP_PRIO	5
48 #define MPTCPOPT_MP_FAIL	6
49 #define MPTCPOPT_MP_FASTCLOSE	7
50 #define MPTCPOPT_RST		8
51 
52 /* MPTCP suboption lengths */
53 #define TCPOLEN_MPTCP_MPC_SYN		4
54 #define TCPOLEN_MPTCP_MPC_SYNACK	12
55 #define TCPOLEN_MPTCP_MPC_ACK		20
56 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
57 #define TCPOLEN_MPTCP_MPJ_SYN		12
58 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
59 #define TCPOLEN_MPTCP_MPJ_ACK		24
60 #define TCPOLEN_MPTCP_DSS_BASE		4
61 #define TCPOLEN_MPTCP_DSS_ACK32		4
62 #define TCPOLEN_MPTCP_DSS_ACK64		8
63 #define TCPOLEN_MPTCP_DSS_MAP32		10
64 #define TCPOLEN_MPTCP_DSS_MAP64		14
65 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
66 #define TCPOLEN_MPTCP_ADD_ADDR		16
67 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
68 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
69 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
70 #define TCPOLEN_MPTCP_ADD_ADDR6		28
71 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
72 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
73 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
74 #define TCPOLEN_MPTCP_PORT_LEN		2
75 #define TCPOLEN_MPTCP_PORT_ALIGN	2
76 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
77 #define TCPOLEN_MPTCP_PRIO		3
78 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
79 #define TCPOLEN_MPTCP_FASTCLOSE		12
80 #define TCPOLEN_MPTCP_RST		4
81 #define TCPOLEN_MPTCP_FAIL		12
82 
83 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
84 
85 /* MPTCP MP_JOIN flags */
86 #define MPTCPOPT_BACKUP		BIT(0)
87 #define MPTCPOPT_THMAC_LEN	8
88 
89 /* MPTCP MP_CAPABLE flags */
90 #define MPTCP_VERSION_MASK	(0x0F)
91 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
92 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
93 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
94 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
95 #define MPTCP_CAP_FLAG_MASK	(0x1F)
96 
97 /* MPTCP DSS flags */
98 #define MPTCP_DSS_DATA_FIN	BIT(4)
99 #define MPTCP_DSS_DSN64		BIT(3)
100 #define MPTCP_DSS_HAS_MAP	BIT(2)
101 #define MPTCP_DSS_ACK64		BIT(1)
102 #define MPTCP_DSS_HAS_ACK	BIT(0)
103 #define MPTCP_DSS_FLAG_MASK	(0x1F)
104 
105 /* MPTCP ADD_ADDR flags */
106 #define MPTCP_ADDR_ECHO		BIT(0)
107 
108 /* MPTCP MP_PRIO flags */
109 #define MPTCP_PRIO_BKUP		BIT(0)
110 
111 /* MPTCP TCPRST flags */
112 #define MPTCP_RST_TRANSIENT	BIT(0)
113 
114 /* MPTCP socket atomic flags */
115 #define MPTCP_WORK_RTX		1
116 #define MPTCP_FALLBACK_DONE	2
117 #define MPTCP_WORK_CLOSE_SUBFLOW 3
118 
119 /* MPTCP socket release cb flags */
120 #define MPTCP_PUSH_PENDING	1
121 #define MPTCP_CLEAN_UNA		2
122 #define MPTCP_ERROR_REPORT	3
123 #define MPTCP_RETRANSMIT	4
124 #define MPTCP_FLUSH_JOIN_LIST	5
125 #define MPTCP_SYNC_STATE	6
126 #define MPTCP_SYNC_SNDBUF	7
127 
128 struct mptcp_skb_cb {
129 	u64 map_seq;
130 	u64 end_seq;
131 	u32 offset;
132 	u8  has_rxtstamp:1;
133 };
134 
135 #define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
136 
137 static inline bool before64(__u64 seq1, __u64 seq2)
138 {
139 	return (__s64)(seq1 - seq2) < 0;
140 }
141 
142 #define after64(seq2, seq1)	before64(seq1, seq2)
143 
144 struct mptcp_options_received {
145 	u64	sndr_key;
146 	u64	rcvr_key;
147 	u64	data_ack;
148 	u64	data_seq;
149 	u32	subflow_seq;
150 	u16	data_len;
151 	__sum16	csum;
152 	u16	suboptions;
153 	u32	token;
154 	u32	nonce;
155 	u16	use_map:1,
156 		dsn64:1,
157 		data_fin:1,
158 		use_ack:1,
159 		ack64:1,
160 		mpc_map:1,
161 		reset_reason:4,
162 		reset_transient:1,
163 		echo:1,
164 		backup:1,
165 		deny_join_id0:1,
166 		__unused:2;
167 	u8	join_id;
168 	u64	thmac;
169 	u8	hmac[MPTCPOPT_HMAC_LEN];
170 	struct mptcp_addr_info addr;
171 	struct mptcp_rm_list rm_list;
172 	u64	ahmac;
173 	u64	fail_seq;
174 };
175 
176 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
177 {
178 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
179 		     ((nib & 0xF) << 8) | field);
180 }
181 
182 enum mptcp_pm_status {
183 	MPTCP_PM_ADD_ADDR_RECEIVED,
184 	MPTCP_PM_ADD_ADDR_SEND_ACK,
185 	MPTCP_PM_RM_ADDR_RECEIVED,
186 	MPTCP_PM_ESTABLISHED,
187 	MPTCP_PM_SUBFLOW_ESTABLISHED,
188 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
189 	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
190 					 * accounted int id_avail_bitmap
191 					 */
192 };
193 
194 enum mptcp_pm_type {
195 	MPTCP_PM_TYPE_KERNEL = 0,
196 	MPTCP_PM_TYPE_USERSPACE,
197 
198 	__MPTCP_PM_TYPE_NR,
199 	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
200 };
201 
202 /* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */
203 #define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)
204 
205 enum mptcp_addr_signal_status {
206 	MPTCP_ADD_ADDR_SIGNAL,
207 	MPTCP_ADD_ADDR_ECHO,
208 	MPTCP_RM_ADDR_SIGNAL,
209 };
210 
211 /* max value of mptcp_addr_info.id */
212 #define MPTCP_PM_MAX_ADDR_ID		U8_MAX
213 
214 struct mptcp_pm_data {
215 	struct mptcp_addr_info local;
216 	struct mptcp_addr_info remote;
217 	struct list_head anno_list;
218 	struct list_head userspace_pm_local_addr_list;
219 
220 	spinlock_t	lock;		/*protects the whole PM data */
221 
222 	u8		addr_signal;
223 	bool		server_side;
224 	bool		work_pending;
225 	bool		accept_addr;
226 	bool		accept_subflow;
227 	bool		remote_deny_join_id0;
228 	u8		add_addr_signaled;
229 	u8		add_addr_accepted;
230 	u8		local_addr_used;
231 	u8		pm_type;
232 	u8		subflows;
233 	u8		status;
234 	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
235 	struct mptcp_rm_list rm_list_tx;
236 	struct mptcp_rm_list rm_list_rx;
237 };
238 
239 struct mptcp_pm_addr_entry {
240 	struct list_head	list;
241 	struct mptcp_addr_info	addr;
242 	u8			flags;
243 	int			ifindex;
244 	struct socket		*lsk;
245 };
246 
247 struct mptcp_data_frag {
248 	struct list_head list;
249 	u64 data_seq;
250 	u16 data_len;
251 	u16 offset;
252 	u16 overhead;
253 	u16 already_sent;
254 	struct page *page;
255 };
256 
257 /* MPTCP connection sock */
258 struct mptcp_sock {
259 	/* inet_connection_sock must be the first member */
260 	struct inet_connection_sock sk;
261 	u64		local_key;		/* protected by the first subflow socket lock
262 						 * lockless access read
263 						 */
264 	u64		remote_key;		/* same as above */
265 	u64		write_seq;
266 	u64		bytes_sent;
267 	u64		snd_nxt;
268 	u64		bytes_received;
269 	u64		ack_seq;
270 	atomic64_t	rcv_wnd_sent;
271 	u64		rcv_data_fin_seq;
272 	u64		bytes_retrans;
273 	u64		bytes_consumed;
274 	int		rmem_fwd_alloc;
275 	int		snd_burst;
276 	int		old_wspace;
277 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
278 						 * recovery related fields are under data_lock
279 						 * protection
280 						 */
281 	u64		bytes_acked;
282 	u64		snd_una;
283 	u64		wnd_end;
284 	u32		last_data_sent;
285 	u32		last_data_recv;
286 	u32		last_ack_recv;
287 	unsigned long	timer_ival;
288 	u32		token;
289 	int		rmem_released;
290 	unsigned long	flags;
291 	unsigned long	cb_flags;
292 	bool		recovery;		/* closing subflow write queue reinjected */
293 	bool		can_ack;
294 	bool		fully_established;
295 	bool		rcv_data_fin;
296 	bool		snd_data_fin_enable;
297 	bool		rcv_fastclose;
298 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
299 	bool		csum_enabled;
300 	bool		allow_infinite_fallback;
301 	u8		pending_state; /* A subflow asked to set this sk_state,
302 					* protected by the msk data lock
303 					*/
304 	u8		mpc_endpoint_id;
305 	u8		recvmsg_inq:1,
306 			cork:1,
307 			nodelay:1,
308 			fastopening:1,
309 			in_accept_queue:1,
310 			free_first:1,
311 			rcvspace_init:1;
312 	u32		notsent_lowat;
313 	int		keepalive_cnt;
314 	int		keepalive_idle;
315 	int		keepalive_intvl;
316 	struct work_struct work;
317 	struct sk_buff  *ooo_last_skb;
318 	struct rb_root  out_of_order_queue;
319 	struct sk_buff_head receive_queue;
320 	struct list_head conn_list;
321 	struct list_head rtx_queue;
322 	struct mptcp_data_frag *first_pending;
323 	struct list_head join_list;
324 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
325 				 * ONCE annotation, the subflow outside the socket
326 				 * lock as such sock is freed after close().
327 				 */
328 	struct mptcp_pm_data	pm;
329 	struct mptcp_sched_ops	*sched;
330 	struct {
331 		u32	space;	/* bytes copied in last measurement window */
332 		u32	copied; /* bytes copied in this measurement window */
333 		u64	time;	/* start time of measurement window */
334 		u64	rtt_us; /* last maximum rtt of subflows */
335 	} rcvq_space;
336 	u8		scaling_ratio;
337 
338 	u32		subflow_id;
339 	u32		setsockopt_seq;
340 	char		ca_name[TCP_CA_NAME_MAX];
341 };
342 
343 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
344 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
345 
346 #define mptcp_for_each_subflow(__msk, __subflow)			\
347 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
348 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
349 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
350 
351 extern struct genl_family mptcp_genl_family;
352 
353 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
354 {
355 	sock_owned_by_me((const struct sock *)msk);
356 }
357 
358 #ifdef CONFIG_DEBUG_NET
359 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
360 #undef tcp_sk
361 #define tcp_sk(ptr) ({								\
362 	typeof(ptr) _ptr = (ptr);						\
363 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
364 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
365 })
366 #define mptcp_sk(ptr) ({						\
367 	typeof(ptr) _ptr = (ptr);					\
368 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
369 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
370 })
371 
372 #else /* !CONFIG_DEBUG_NET */
373 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
374 #endif
375 
376 /* the msk socket don't use the backlog, also account for the bulk
377  * free memory
378  */
379 static inline int __mptcp_rmem(const struct sock *sk)
380 {
381 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
382 }
383 
384 static inline int mptcp_win_from_space(const struct sock *sk, int space)
385 {
386 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
387 }
388 
389 static inline int mptcp_space_from_win(const struct sock *sk, int win)
390 {
391 	return __tcp_space_from_win(mptcp_sk(sk)->scaling_ratio, win);
392 }
393 
394 static inline int __mptcp_space(const struct sock *sk)
395 {
396 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
397 }
398 
399 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
400 {
401 	const struct mptcp_sock *msk = mptcp_sk(sk);
402 
403 	return READ_ONCE(msk->first_pending);
404 }
405 
406 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
407 {
408 	struct mptcp_sock *msk = mptcp_sk(sk);
409 	struct mptcp_data_frag *cur;
410 
411 	cur = msk->first_pending;
412 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
413 						     list_next_entry(cur, list);
414 }
415 
416 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
417 {
418 	const struct mptcp_sock *msk = mptcp_sk(sk);
419 
420 	if (!msk->first_pending)
421 		return NULL;
422 
423 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
424 		return NULL;
425 
426 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
427 }
428 
429 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
430 {
431 	struct mptcp_sock *msk = mptcp_sk(sk);
432 
433 	if (msk->snd_una == msk->snd_nxt)
434 		return NULL;
435 
436 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
437 }
438 
439 struct csum_pseudo_header {
440 	__be64 data_seq;
441 	__be32 subflow_seq;
442 	__be16 data_len;
443 	__sum16 csum;
444 };
445 
446 struct mptcp_subflow_request_sock {
447 	struct	tcp_request_sock sk;
448 	u16	mp_capable : 1,
449 		mp_join : 1,
450 		backup : 1,
451 		request_bkup : 1,
452 		csum_reqd : 1,
453 		allow_join_id0 : 1;
454 	u8	local_id;
455 	u8	remote_id;
456 	u64	local_key;
457 	u64	idsn;
458 	u32	token;
459 	u32	ssn_offset;
460 	u64	thmac;
461 	u32	local_nonce;
462 	u32	remote_nonce;
463 	struct mptcp_sock	*msk;
464 	struct hlist_nulls_node token_node;
465 };
466 
467 static inline struct mptcp_subflow_request_sock *
468 mptcp_subflow_rsk(const struct request_sock *rsk)
469 {
470 	return (struct mptcp_subflow_request_sock *)rsk;
471 }
472 
473 struct mptcp_delegated_action {
474 	struct napi_struct napi;
475 	struct list_head head;
476 };
477 
478 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
479 
480 #define MPTCP_DELEGATE_SCHEDULED	0
481 #define MPTCP_DELEGATE_SEND		1
482 #define MPTCP_DELEGATE_ACK		2
483 #define MPTCP_DELEGATE_SNDBUF		3
484 
485 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
486 /* MPTCP subflow context */
487 struct mptcp_subflow_context {
488 	struct	list_head node;/* conn_list of subflows */
489 
490 	struct_group(reset,
491 
492 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
493 	u64	local_key;
494 	u64	remote_key;
495 	u64	idsn;
496 	u64	map_seq;
497 	u32	snd_isn;
498 	u32	token;
499 	u32	rel_write_seq;
500 	u32	map_subflow_seq;
501 	u32	ssn_offset;
502 	u32	map_data_len;
503 	__wsum	map_data_csum;
504 	u32	map_csum_len;
505 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
506 		request_join : 1,   /* send MP_JOIN */
507 		request_bkup : 1,
508 		mp_capable : 1,	    /* remote is MPTCP capable */
509 		mp_join : 1,	    /* remote is JOINing */
510 		fully_established : 1,	    /* path validated */
511 		pm_notified : 1,    /* PM hook called for established status */
512 		conn_finished : 1,
513 		map_valid : 1,
514 		map_csum_reqd : 1,
515 		map_data_fin : 1,
516 		mpc_map : 1,
517 		backup : 1,
518 		send_mp_prio : 1,
519 		send_mp_fail : 1,
520 		send_fastclose : 1,
521 		send_infinite_map : 1,
522 		remote_key_valid : 1,        /* received the peer key from */
523 		disposable : 1,	    /* ctx can be free at ulp release time */
524 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
525 		valid_csum_seen : 1,        /* at least one csum validated */
526 		is_mptfo : 1,	    /* subflow is doing TFO */
527 		__unused : 10;
528 	bool	data_avail;
529 	bool	scheduled;
530 	u32	remote_nonce;
531 	u64	thmac;
532 	u32	local_nonce;
533 	u32	remote_token;
534 	union {
535 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
536 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
537 	};
538 	s16	local_id;	    /* if negative not initialized yet */
539 	u8	remote_id;
540 	u8	reset_seen:1;
541 	u8	reset_transient:1;
542 	u8	reset_reason:4;
543 	u8	stale_count;
544 
545 	u32	subflow_id;
546 
547 	long	delegated_status;
548 	unsigned long	fail_tout;
549 
550 	);
551 
552 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
553 
554 	u32	setsockopt_seq;
555 	u32	stale_rcv_tstamp;
556 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
557 				     * protected by the msk socket lock
558 				     */
559 
560 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
561 	struct	sock *conn;	    /* parent mptcp_sock */
562 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
563 	void	(*tcp_state_change)(struct sock *sk);
564 	void	(*tcp_error_report)(struct sock *sk);
565 
566 	struct	rcu_head rcu;
567 };
568 
569 static inline struct mptcp_subflow_context *
570 mptcp_subflow_ctx(const struct sock *sk)
571 {
572 	const struct inet_connection_sock *icsk = inet_csk(sk);
573 
574 	/* Use RCU on icsk_ulp_data only for sock diag code */
575 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
576 }
577 
578 static inline struct sock *
579 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
580 {
581 	return subflow->tcp_sock;
582 }
583 
584 static inline void
585 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
586 {
587 	memset(&subflow->reset, 0, sizeof(subflow->reset));
588 	subflow->request_mptcp = 1;
589 	WRITE_ONCE(subflow->local_id, -1);
590 }
591 
592 /* Convert reset reasons in MPTCP to enum sk_rst_reason type */
593 static inline enum sk_rst_reason
594 sk_rst_convert_mptcp_reason(u32 reason)
595 {
596 	switch (reason) {
597 	case MPTCP_RST_EUNSPEC:
598 		return SK_RST_REASON_MPTCP_RST_EUNSPEC;
599 	case MPTCP_RST_EMPTCP:
600 		return SK_RST_REASON_MPTCP_RST_EMPTCP;
601 	case MPTCP_RST_ERESOURCE:
602 		return SK_RST_REASON_MPTCP_RST_ERESOURCE;
603 	case MPTCP_RST_EPROHIBIT:
604 		return SK_RST_REASON_MPTCP_RST_EPROHIBIT;
605 	case MPTCP_RST_EWQ2BIG:
606 		return SK_RST_REASON_MPTCP_RST_EWQ2BIG;
607 	case MPTCP_RST_EBADPERF:
608 		return SK_RST_REASON_MPTCP_RST_EBADPERF;
609 	case MPTCP_RST_EMIDDLEBOX:
610 		return SK_RST_REASON_MPTCP_RST_EMIDDLEBOX;
611 	default:
612 		/* It should not happen, or else errors may occur
613 		 * in MPTCP layer
614 		 */
615 		return SK_RST_REASON_ERROR;
616 	}
617 }
618 
619 static inline void
620 mptcp_send_active_reset_reason(struct sock *sk)
621 {
622 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
623 	enum sk_rst_reason reason;
624 
625 	reason = sk_rst_convert_mptcp_reason(subflow->reset_reason);
626 	tcp_send_active_reset(sk, GFP_ATOMIC, reason);
627 }
628 
629 static inline u64
630 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
631 {
632 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
633 		      subflow->ssn_offset -
634 		      subflow->map_subflow_seq;
635 }
636 
637 static inline u64
638 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
639 {
640 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
641 }
642 
643 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
644 
645 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
646 {
647 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
648 	struct mptcp_delegated_action *delegated;
649 	bool schedule;
650 
651 	/* the caller held the subflow bh socket lock */
652 	lockdep_assert_in_softirq();
653 
654 	/* The implied barrier pairs with tcp_release_cb_override()
655 	 * mptcp_napi_poll(), and ensures the below list check sees list
656 	 * updates done prior to delegated status bits changes
657 	 */
658 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
659 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
660 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
661 			return;
662 
663 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
664 		schedule = list_empty(&delegated->head);
665 		list_add_tail(&subflow->delegated_node, &delegated->head);
666 		sock_hold(mptcp_subflow_tcp_sock(subflow));
667 		if (schedule)
668 			napi_schedule(&delegated->napi);
669 	}
670 }
671 
672 static inline struct mptcp_subflow_context *
673 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
674 {
675 	struct mptcp_subflow_context *ret;
676 
677 	if (list_empty(&delegated->head))
678 		return NULL;
679 
680 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
681 	list_del_init(&ret->delegated_node);
682 	return ret;
683 }
684 
685 int mptcp_is_enabled(const struct net *net);
686 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
687 int mptcp_is_checksum_enabled(const struct net *net);
688 int mptcp_allow_join_id0(const struct net *net);
689 unsigned int mptcp_stale_loss_cnt(const struct net *net);
690 unsigned int mptcp_close_timeout(const struct sock *sk);
691 int mptcp_get_pm_type(const struct net *net);
692 const char *mptcp_get_scheduler(const struct net *net);
693 void mptcp_get_available_schedulers(char *buf, size_t maxlen);
694 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
695 				       struct mptcp_subflow_context *subflow,
696 				       const struct mptcp_options_received *mp_opt);
697 bool __mptcp_retransmit_pending_data(struct sock *sk);
698 void mptcp_check_and_set_pending(struct sock *sk);
699 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
700 bool mptcp_subflow_data_available(struct sock *sk);
701 void __init mptcp_subflow_init(void);
702 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
703 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
704 		     struct mptcp_subflow_context *subflow);
705 void __mptcp_subflow_send_ack(struct sock *ssk);
706 void mptcp_subflow_reset(struct sock *ssk);
707 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
708 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
709 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
710 bool __mptcp_close(struct sock *sk, long timeout);
711 void mptcp_cancel_work(struct sock *sk);
712 void __mptcp_unaccepted_force_close(struct sock *sk);
713 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
714 void mptcp_set_state(struct sock *sk, int state);
715 
716 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
717 			   const struct mptcp_addr_info *b, bool use_port);
718 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
719 
720 /* called with sk socket lock held */
721 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
722 			    const struct mptcp_addr_info *remote);
723 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
724 				struct socket **new_sock);
725 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
726 			 struct sockaddr_storage *addr,
727 			 unsigned short family);
728 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
729 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
730 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
731 void mptcp_sched_init(void);
732 int mptcp_init_sched(struct mptcp_sock *msk,
733 		     struct mptcp_sched_ops *sched);
734 void mptcp_release_sched(struct mptcp_sock *msk);
735 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
736 				 bool scheduled);
737 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
738 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
739 int mptcp_sched_get_send(struct mptcp_sock *msk);
740 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
741 
742 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
743 {
744 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
745 }
746 
747 static inline bool mptcp_epollin_ready(const struct sock *sk)
748 {
749 	/* mptcp doesn't have to deal with small skbs in the receive queue,
750 	 * at it can always coalesce them
751 	 */
752 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
753 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
754 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
755 	       READ_ONCE(tcp_memory_pressure);
756 }
757 
758 int mptcp_set_rcvlowat(struct sock *sk, int val);
759 
760 static inline bool __tcp_can_send(const struct sock *ssk)
761 {
762 	/* only send if our side has not closed yet */
763 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
764 }
765 
766 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
767 {
768 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
769 	if (subflow->request_join && !subflow->fully_established)
770 		return false;
771 
772 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
773 }
774 
775 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
776 
777 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
778 
779 void mptcp_subflow_drop_ctx(struct sock *ssk);
780 
781 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
782 					      struct mptcp_subflow_context *ctx)
783 {
784 	sk->sk_data_ready = sock_def_readable;
785 	sk->sk_state_change = ctx->tcp_state_change;
786 	sk->sk_write_space = sk_stream_write_space;
787 	sk->sk_error_report = ctx->tcp_error_report;
788 
789 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
790 }
791 
792 void __init mptcp_proto_init(void);
793 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
794 int __init mptcp_proto_v6_init(void);
795 #endif
796 
797 struct sock *mptcp_sk_clone_init(const struct sock *sk,
798 				 const struct mptcp_options_received *mp_opt,
799 				 struct sock *ssk,
800 				 struct request_sock *req);
801 void mptcp_get_options(const struct sk_buff *skb,
802 		       struct mptcp_options_received *mp_opt);
803 
804 void mptcp_finish_connect(struct sock *sk);
805 void __mptcp_sync_state(struct sock *sk, int state);
806 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
807 
808 static inline void mptcp_stop_tout_timer(struct sock *sk)
809 {
810 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
811 		return;
812 
813 	sk_stop_timer(sk, &sk->sk_timer);
814 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
815 }
816 
817 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
818 {
819 	/* avoid 0 timestamp, as that means no close timeout */
820 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
821 }
822 
823 static inline void mptcp_start_tout_timer(struct sock *sk)
824 {
825 	mptcp_set_close_tout(sk, tcp_jiffies32);
826 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
827 }
828 
829 static inline bool mptcp_is_fully_established(struct sock *sk)
830 {
831 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
832 	       READ_ONCE(mptcp_sk(sk)->fully_established);
833 }
834 
835 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
836 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
837 bool mptcp_finish_join(struct sock *sk);
838 bool mptcp_schedule_work(struct sock *sk);
839 int mptcp_setsockopt(struct sock *sk, int level, int optname,
840 		     sockptr_t optval, unsigned int optlen);
841 int mptcp_getsockopt(struct sock *sk, int level, int optname,
842 		     char __user *optval, int __user *option);
843 
844 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
845 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
846 {
847 	if (use_64bit)
848 		return cur_seq;
849 
850 	return __mptcp_expand_seq(old_seq, cur_seq);
851 }
852 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
853 void __mptcp_data_acked(struct sock *sk);
854 void __mptcp_error_report(struct sock *sk);
855 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
856 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
857 {
858 	return READ_ONCE(msk->snd_data_fin_enable) &&
859 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
860 }
861 
862 static inline u32 mptcp_notsent_lowat(const struct sock *sk)
863 {
864 	struct net *net = sock_net(sk);
865 	u32 val;
866 
867 	val = READ_ONCE(mptcp_sk(sk)->notsent_lowat);
868 	return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
869 }
870 
871 static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake)
872 {
873 	const struct mptcp_sock *msk = mptcp_sk(sk);
874 	u32 notsent_bytes;
875 
876 	notsent_bytes = READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt);
877 	return (notsent_bytes << wake) < mptcp_notsent_lowat(sk);
878 }
879 
880 static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake)
881 {
882 	return mptcp_stream_memory_free(sk, wake) &&
883 	       __sk_stream_is_writeable(sk, wake);
884 }
885 
886 static inline void mptcp_write_space(struct sock *sk)
887 {
888 	/* pairs with memory barrier in mptcp_poll */
889 	smp_mb();
890 	if (mptcp_stream_memory_free(sk, 1))
891 		sk_stream_write_space(sk);
892 }
893 
894 static inline void __mptcp_sync_sndbuf(struct sock *sk)
895 {
896 	struct mptcp_subflow_context *subflow;
897 	int ssk_sndbuf, new_sndbuf;
898 
899 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
900 		return;
901 
902 	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
903 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
904 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
905 
906 		subflow->cached_sndbuf = ssk_sndbuf;
907 		new_sndbuf += ssk_sndbuf;
908 	}
909 
910 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
911 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
912 	mptcp_write_space(sk);
913 }
914 
915 /* The called held both the msk socket and the subflow socket locks,
916  * possibly under BH
917  */
918 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
919 {
920 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
921 
922 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
923 		__mptcp_sync_sndbuf(sk);
924 }
925 
926 /* the caller held only the subflow socket lock, either in process or
927  * BH context. Additionally this can be called under the msk data lock,
928  * so we can't acquire such lock here: let the delegate action acquires
929  * the needed locks in suitable order.
930  */
931 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
932 {
933 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
934 
935 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
936 		return;
937 
938 	local_bh_disable();
939 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
940 	local_bh_enable();
941 }
942 
943 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
944 
945 #define MPTCP_TOKEN_MAX_RETRIES	4
946 
947 void __init mptcp_token_init(void);
948 static inline void mptcp_token_init_request(struct request_sock *req)
949 {
950 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
951 }
952 
953 int mptcp_token_new_request(struct request_sock *req);
954 void mptcp_token_destroy_request(struct request_sock *req);
955 int mptcp_token_new_connect(struct sock *ssk);
956 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
957 			struct mptcp_sock *msk);
958 bool mptcp_token_exists(u32 token);
959 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
960 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
961 					 long *s_num);
962 void mptcp_token_destroy(struct mptcp_sock *msk);
963 
964 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
965 
966 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
967 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
968 
969 void __init mptcp_pm_init(void);
970 void mptcp_pm_data_init(struct mptcp_sock *msk);
971 void mptcp_pm_data_reset(struct mptcp_sock *msk);
972 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
973 			struct mptcp_addr_info *addr);
974 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
975 			 bool require_family,
976 			 struct mptcp_pm_addr_entry *entry);
977 bool mptcp_pm_addr_families_match(const struct sock *sk,
978 				  const struct mptcp_addr_info *loc,
979 				  const struct mptcp_addr_info *rem);
980 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
981 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
982 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
983 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
984 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
985 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
986 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
987 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
988 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
989 				 const struct mptcp_subflow_context *subflow);
990 void mptcp_pm_add_addr_received(const struct sock *ssk,
991 				const struct mptcp_addr_info *addr);
992 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
993 			      const struct mptcp_addr_info *addr);
994 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
995 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
996 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
997 			       const struct mptcp_rm_list *rm_list);
998 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
999 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
1000 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
1001 				 struct mptcp_addr_info *addr,
1002 				 struct mptcp_addr_info *rem,
1003 				 u8 bkup);
1004 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
1005 			      const struct mptcp_addr_info *addr);
1006 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
1007 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
1008 struct mptcp_pm_add_entry *
1009 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
1010 		       const struct mptcp_addr_info *addr, bool check_id);
1011 struct mptcp_pm_add_entry *
1012 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
1013 				const struct mptcp_addr_info *addr);
1014 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1015 					 unsigned int id,
1016 					 u8 *flags, int *ifindex);
1017 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
1018 					    u8 *flags, int *ifindex);
1019 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1020 						   unsigned int id,
1021 						   u8 *flags, int *ifindex);
1022 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1023 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
1024 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1025 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
1026 			   const struct mptcp_addr_info *addr,
1027 			   bool echo);
1028 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
1029 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
1030 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
1031 
1032 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
1033 
1034 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
1035 		 const struct sock *ssk, gfp_t gfp);
1036 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
1037 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
1038 void mptcp_event_pm_listener(const struct sock *ssk,
1039 			     enum mptcp_event_type event);
1040 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
1041 
1042 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
1043 				     const struct mptcp_options_received *mp_opt);
1044 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
1045 					      struct request_sock *req);
1046 int mptcp_nl_fill_addr(struct sk_buff *skb,
1047 		       struct mptcp_pm_addr_entry *entry);
1048 
1049 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
1050 {
1051 	return READ_ONCE(msk->pm.addr_signal) &
1052 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
1053 }
1054 
1055 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
1056 {
1057 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
1058 }
1059 
1060 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
1061 {
1062 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
1063 }
1064 
1065 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
1066 {
1067 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
1068 }
1069 
1070 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1071 {
1072 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1073 }
1074 
1075 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1076 {
1077 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1078 }
1079 
1080 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1081 {
1082 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1083 
1084 	if (family == AF_INET6)
1085 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1086 	if (!echo)
1087 		len += MPTCPOPT_THMAC_LEN;
1088 	/* account for 2 trailing 'nop' options */
1089 	if (port)
1090 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1091 
1092 	return len;
1093 }
1094 
1095 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1096 {
1097 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1098 		return -EINVAL;
1099 
1100 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1101 }
1102 
1103 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1104 			      unsigned int opt_size, unsigned int remaining,
1105 			      struct mptcp_addr_info *addr, bool *echo,
1106 			      bool *drop_other_suboptions);
1107 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1108 			     struct mptcp_rm_list *rm_list);
1109 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1110 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1111 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1112 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
1113 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1114 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1115 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
1116 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1117 			  struct netlink_callback *cb);
1118 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
1119 				 struct netlink_callback *cb);
1120 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info);
1121 int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info);
1122 int mptcp_userspace_pm_get_addr(struct sk_buff *skb,
1123 				struct genl_info *info);
1124 
1125 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1126 {
1127 	int local_id = READ_ONCE(subflow->local_id);
1128 
1129 	if (local_id < 0)
1130 		return 0;
1131 	return local_id;
1132 }
1133 
1134 void __init mptcp_pm_nl_init(void);
1135 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1136 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1137 				     const struct mptcp_rm_list *rm_list);
1138 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1139 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1140 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1141 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1142 
1143 /* called under PM lock */
1144 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1145 {
1146 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1147 		WRITE_ONCE(msk->pm.accept_subflow, true);
1148 }
1149 
1150 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1151 {
1152 	spin_lock_bh(&msk->pm.lock);
1153 	__mptcp_pm_close_subflow(msk);
1154 	spin_unlock_bh(&msk->pm.lock);
1155 }
1156 
1157 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1158 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1159 
1160 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1161 {
1162 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1163 }
1164 
1165 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1166 
1167 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1168 {
1169 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1170 }
1171 
1172 static inline bool mptcp_check_fallback(const struct sock *sk)
1173 {
1174 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1175 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1176 
1177 	return __mptcp_check_fallback(msk);
1178 }
1179 
1180 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1181 {
1182 	if (__mptcp_check_fallback(msk)) {
1183 		pr_debug("TCP fallback already done (msk=%p)", msk);
1184 		return;
1185 	}
1186 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1187 }
1188 
1189 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1190 {
1191 	struct sock *ssk = READ_ONCE(msk->first);
1192 
1193 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1194 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1195 			TCPF_SYN_RECV | TCPF_LISTEN));
1196 }
1197 
1198 static inline void mptcp_do_fallback(struct sock *ssk)
1199 {
1200 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1201 	struct sock *sk = subflow->conn;
1202 	struct mptcp_sock *msk;
1203 
1204 	msk = mptcp_sk(sk);
1205 	__mptcp_do_fallback(msk);
1206 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1207 		gfp_t saved_allocation = ssk->sk_allocation;
1208 
1209 		/* we are in a atomic (BH) scope, override ssk default for data
1210 		 * fin allocation
1211 		 */
1212 		ssk->sk_allocation = GFP_ATOMIC;
1213 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1214 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1215 		ssk->sk_allocation = saved_allocation;
1216 	}
1217 }
1218 
1219 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1220 
1221 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1222 {
1223 	struct mptcp_ext *mpext;
1224 
1225 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1226 	if (mpext && mpext->infinite_map)
1227 		return true;
1228 
1229 	return false;
1230 }
1231 
1232 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1233 {
1234 	return (subflow->request_mptcp || subflow->request_join);
1235 }
1236 
1237 static inline bool subflow_simultaneous_connect(struct sock *sk)
1238 {
1239 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1240 
1241 	return (1 << sk->sk_state) &
1242 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1243 	       is_active_ssk(subflow) &&
1244 	       !subflow->conn_finished;
1245 }
1246 
1247 #ifdef CONFIG_SYN_COOKIES
1248 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1249 				       struct sk_buff *skb);
1250 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1251 					struct sk_buff *skb);
1252 void __init mptcp_join_cookie_init(void);
1253 #else
1254 static inline void
1255 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1256 				  struct sk_buff *skb) {}
1257 static inline bool
1258 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1259 				   struct sk_buff *skb)
1260 {
1261 	return false;
1262 }
1263 
1264 static inline void mptcp_join_cookie_init(void) {}
1265 #endif
1266 
1267 #endif /* __MPTCP_PROTOCOL_H */
1268